timing
MOCD1
X-band high gradient accelerating structure for VIGAS project at Tsinghua university
14
A light source project named Very Compact Inverse Compton Gamma-ray Source (VIGAS) is under development at Tsinghua University. VIGAS aims to generate monochromatic high-energy gamma rays by colliding a 350 MeV electron beam with a 400-nm laser. To produce a high-energy electron beam in a compact accelerator with a length shorter than 12 meters, the system consists of an S-band high-brightness injector and six X-band high-gradient accelerating structures. The X-band structure’s frequency is 11.424 GHz, and it adopts a constant gradient traveling wave approach; thus, the iris from the first cell to the end cell is tapered. The total cell number is 72, so we named it XT72. In the last two years, we conducted the design, fabrication, and tuning of the first prototype of XT72. Recently, we finished the high-power test, and the result demonstrates that it has the ability to work at an 80 MV/m gradient. In this paper, we present the latest update on this structure.
Paper: MOCD1
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOCD1
About: Received: 05 May 2024 — Revised: 20 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
MOCN1
Performance of a longitudinal bunch by bunch feedback in a system with a passive harmonic cavity
21
While designed to be inherently stable, the accelerator upgrade SLS 2.0 will have a longitudinal multi-bunch feedback system, to be used as a diagnostics device and as a fallback against unexpected problems. Modelling the performance of the system is complicated by the presence of a passive harmonic cavity introduced for longer bunch lengths and correspondingly higher stability thresholds, which has the following effects: the voltage of the harmonic cavity varies with the beam current leading to a variation of the synchronous frequency, specially pronounced in the initial injection at very low currents. Even at full current, the presence of the ion clearing gap provokes transients in the main and harmonic system leading to a transient variation of the synchronous frequency over the bunch train. Another effect of the RF transients is a variation in the synchronous phase over the bunch train, which leads to cross talk effects, the open loop gain starts to vary with the order of the coupled bunch oscillation. The feedback filter needs to take account of all these effects for a satisfactory performance.
Paper: MOCN1
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOCN1
About: Received: 13 May 2024 — Revised: 21 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPC02
ZDC effective cross section for Gold-Gold Collisions During RHIC'S Run 16
32
The 2016 Relativistic Heavy Ion Collider (RHIC) Au-Au run took place from January 25 to June 27, 2016. Four so-called vernier scans were performed at 100 GeV per beam, with γ=107.396 at flattop at one of the interaction points, IP6. During this type of procedure, one beam is swept across the other, first horizontally and then vertically, recording the interaction rate as a function of the beam to beam separation. From that data, the effective cross section of the Zero Degree Calorimeter (ZDC) can be derived. This paper discusses the results of the scans, as well as the systematic uncertainties of the derived effective cross section.
Paper: MOPC02
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPC02
About: Received: 14 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
MOPC07
RHIC Au-Au operation at 100 GeV in Run 23
48
The Relativistic Heavy Ion Collider (RHIC) Run 23 program consisted of collisions of 100 GeV gold beams at two collision points for the first time since 2016; the sPHENIX collaboration used the beam to commission their new detector systems while STAR took physics data. Completion of sPHENIX construction pushed the start of the run to May, forcing the collider complex to operate over the summer months and incurring lower than normal availability due to heat and power dip related problems. Issues with dynamic pressure rise during acceleration through transition resulted in a slower ramp up of intensity compared to prior years. Finally, a failure of a warm-to-cold current lead interface in the valve box for the Main Magnet power supply forced the run to end. This paper will discuss the progress made by each experiment and the failure mode, repair and mitigation efforts in preparation for Run 24.
Paper: MOPC07
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPC07
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPC11
Correlating start-of-ramp losses with beam observables at blat-bottom in the LHC
63
Power limitations are expected at injection energy for the main Radio Frequency (RF) system due to the doubled bunch intensity in the High Luminosity (HL-) Large Hadron Collider (LHC) era. One way to overcome these power limitations is to reduce the capture voltage. The smaller RF bucket, however, leads to increased beam losses at the start of the ramp. In practice, these beam losses, which contain both capture and flat-bottom losses, can trigger beam dumps if any of the Beam Loss Monitor (BLM) thresholds are reached. In this contribution, the correlation between start-of-ramp beam loss and beam observables before the ramp is investigated by analysing Beam Current Transformer (BCT) measurements from physics fills. Estimates of how the maximum ratio to BLM dump threshold scales with longitudinal losses are also made. The aim is to make predictions for operation at higher bunch intensities on the basis of these correlations in view of the intensity ramp up for the HL-LHC era.
Paper: MOPC11
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPC11
About: Received: 14 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
MOPC12
LHC optics commissioning in 2023 and 2024
67
The LHC machine configuration was changed in 2023 compared to previous years, requiring a new set of optics configurations to be measured and corrected. A telescopic optics was deployed in energy the ramp for the first time, which gave rise to a beta-beating of up to 25%. This was corrected using a global correction approach which reduced the beta-beat down to 10%. A change in the phase advance at injection was also applied to mitigate the negative effect of the main octupoles used to stabilize the beam. These measurements and corrections, coupled with the results from the 2024 commissioning, will be presented in this paper
Paper: MOPC12
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPC12
About: Received: 10 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPC39
Initial results from 35 keV H+ beam at the LANL RFQ test stand
149
The Los Alamos Neutron Science Center (LASNCE) is over 50 years old. Currently, Cockroft-Waltons are being used to accelerate H+ and H- beams to 750 keV. The LANSCE Modernization Project (LAMP) is proposing to replace the font-end of LANSCE with a Radio-Frequency Quadrupole (RFQ). A RFQ Test Stand is being commissioned at LANL for technical demonstration of simultaneous dual-beam species acceleration through a RFQ under the timing constraints required by the LANSCE users facilities. We will describe the status and present initial results of the 35keV H+ line on the RFQ Test Stand.
Paper: MOPC39
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPC39
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
MOPC44
Transfer learning for field emission mitigation in CEBAF SRF cavities
160
The Continuous Electron Beam Accelerator Facility (CEBAF) operates hundreds of superconducting radio frequency (SRF) cavities in its two linear accelerators (linacs). Field emission (FE) is an ongoing operational challenge in higher gradient SRF cavities. FE generates high levels of neutron and gamma radiation leading to damaged accelerator hardware and a radiation hazard environment. During machine development periods, we performed invasive gradient scans to record data capturing the relationship between cavity gradients and radiation levels measured throughout the linacs. However, the field emission environment at CEBAF varies considerably over time as the configuration of the radio-frequency (RF) gradients changes or due to the strengthening of existing field emitters or the abrupt appearance of new field emitters. To mitigate FE and lower the radiation levels, an artificial intelligence/machine learning (AI/ML) approach with transfer learning is needed. In this work, we mainly focus on leveraging the RF trip data gathered during CEBAF normal operation. We develop a transfer learning based surrogate model for radiation detector readings given RF cavity gradients to track the CEBAF’s changing configuration and environment. Then, we could use the developed model as an optimization process for redistributing the RF gradients within a linac to mitigate field emission.
Paper: MOPC44
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPC44
About: Received: 14 May 2024 — Revised: 11 Jun 2024 — Accepted: 11 Jun 2024 — Issue date: 01 Jul 2024
MOPC61
Studies of space-charge compensation of positive ions by creating time-dependent secondary electrons in low-energy beam transport line
201
The space-charge neutralization of an ion beam by created electrons when the beam ionizes the gas is investigated using a three-dimensional electrostatic particle-in-cell code. Different kinds of injected gases are considered, and their space-charge compensation transient times are compared. The created secondary electrons by the beam collision with neutral gas along the beam trajectories are loaded in the simulation by a Monte Carlo generator, and their space charge contribution is added to the primary beam space charge densities. The injection and accumulation of secondaries are time-dependent and this process is continued until total space charge densities reach a steady state. In this study, a 2.4-meter LEBT line with two solenoid magnets is considered. Usually, the proton beam energy is 25 keV and the current level is around 10-15 mA. Additionally, beam extraction studies are conducted, and the extracted beam is used in both IBSIMU and Tracewin codes for LEBT lines to validate the results.
Paper: MOPC61
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPC61
About: Received: 13 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
MOPG05
Low-alpha operation of the IOTA storage ring
296
Operation with ultra-low momentum-compaction factor (alpha) is a desirable capability for many storage rings and synchrotron radiation sources. For example, low-alpha lattices are commonly used to produce picosecond bunches for the generation of coherent THz radiation and are the basis of a number of conceptual designs for EUV generation via steady-state microbunching (SSMB). Achieving ultra-low alpha requires not only a high-level of stability in the linear optics but also flexible control of higher-order compaction terms. Operation with lower momentum-compaction lattices has recently been investigated at the IOTA storage ring at Fermilab. Experimental results from some initial feasibility studies will be discussed in the context of ensuring an improved understanding of the IOTA optics for future research programs.
Paper: MOPG05
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPG05
About: Received: 24 May 2024 — Revised: 28 May 2024 — Accepted: 28 May 2024 — Issue date: 01 Jul 2024
MOPG07
Dispersion orbit detection by orbit harmonic analysis and potential applications
304
Electron storage rings in synchrotron light sources are typically composed of 𝑁 identical sectors that repeat over the ring. Transverse plane betatron frequencies are not an integer harmonic of the beam revolution frequency to avoid that accelerator imperfection effects are turn-by-turn amplified causing beam losses. Consequently, orbit variations induced by ring parameters not affecting beam energy, do not show periodicity equal to 𝑁, while variations affecting energy do generate dispersion orbits with 𝑁 periodicity. In the relativistic case, the beam energy in a ring is set by its closed orbit length (defined by the RF frequency) jointly with the field in bend magnets. Ring thermal expansion/compression causes energy variations and periodic dispersion orbits. In the frequency domain, the real-time amplitude of these orbits can be determined from their 𝑁 spectral line magnitude and phase. This info can be used in orbit feedbacks to adjust the RF to remove orbit dispersion components avoiding conflict with the corrector magnet action. Initial measurements performed at the Advanced Light Source in Berkeley to validate the technique are presented. Additional application possibilities are also discussed.
Paper: MOPG07
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPG07
About: Received: 14 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
MOPG09
A faster algorithm to compute lowest order longitudinal and transverse resistive wall wake for non-ultrarelativistic case
312
With the development of the steady state micro bunching (SSMB) storage ring, its parameters reveal that the ultra relativistic assumption which is wildly used is not valid for the electron beam bunch train, which has length in the 100 nm range, spacing of 1 μm and energy in hundreds MeV range. The strength of the interaction between such bunches and the potential instability may need careful evaluation. At the same time, the effect of the space charge inside a single bunch due to space charge effect also needs to be considered. In this article, we reorganized the lowest-order longitudinal wakefield under non-ultra relativistic conditions, and the lowest-order transverse wakefield. We present the modified theoretical results and analysis. Then based on the result we have derived, we give a algorithm which is thousands time faster than direct calculation. It lays foundation in future research.
Paper: MOPG09
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPG09
About: Received: 14 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
MOPG14
The CXFEL project at Arizona State University
331
The CXFEL is designed to produce attosecond-femtosecond pulses of soft X-rays in the range 300-2500 eV using nanobunched electron beams and a very high power laser undulator. The project includes 5 X-ray endstations with applications in biology, quantum materials, and AMO science. The CXFEL Project overall includes both the CXFEL and the nonlasing hard X-ray CXLS that is described elsewhere in these proceedings. The CXFEL has recently completed a 3-year design phase and received NSF funding in March 2023 for construction over the next 5 years. Both CXFEL and CXLS instruments use recently developed X-band distributed-coupling, room-temperature, standing-wave linacs and photoinjectors operating at 1 kHz repetition rates and 9300 MHz RF frequency. They rely on recently developed Yb-based lasers operating at high peak and average power to produce fs pulses of 1030 nm light at 1 kHz repetition rate with pulse energy up to 400 mJ. We present the design and initial construction activities of the large collaborative effort to develop the fully coherent CXFEL.
Paper: MOPG14
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPG14
About: Received: 23 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPR26
Test of a metamaterial structure for structure-based wakefield acceleration
515
Metamaterial accelerators driven by nanosecond-long RF pulses show promise to mitigate RF breakdown. Recent high-power tests at the Argonne Wakefield Accelerator (AWA) with an X-band metamaterial structure have demonstrated to achieve a gradient of 190 MV/m, while we also observed a new acceleration regime, the breakdown-insensitive acceleration regime (BIAR), where the RF breakdown may not interrupt acceleration of a main beam. Statistical analysis between different breakdown types reveals that the characteristics of the BIAR breakdown are beneficial to high-gradient acceleration at short pulse lengths.
Paper: MOPR26
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPR26
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPR29
High gradient C-band cryogenic copper silver structures
519
C-band accelerators have been of particular interest in recent years due to their ability to provide high gradients and transport high charge beams for applications such as colliders and medical technologies. New Advancements in high gradient technologies that can suppress the breakdown rate in a particular structure by using distributed coupling, cryogenic cooling, and copper alloys. Previous work has shown each of these separately to significantly improve the maximum gradient. In this work, for the first time, we will combine all three methods in an ultra-high gradient structure and benchmark the difference between Cu and CuAg. The exact same structures were previously tested at room temperature and showed gradients in excess of 200 MeV/m and a 20% improvement in the CuAg version over its pure Cu counterpart [1]. These structures are now tested at 77K simultaneously. They were found to perform similarly due to the presence of significant beam loading. Taking beam loading into account, a maximum achievable gradient of 200 MeV/m achieved for a 1 µs pulse at an input power of 5 MW into each cavity with a breakdown rate of 1e-1 breakdown/pulse/m.
Paper: MOPR29
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPR29
About: Received: 15 May 2024 — Revised: 22 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
MOPR39
Investigation of plasma stability of the prototype plasma lens for positron matching
538
The quest for novel technologies in the ever-evolving landscape of scientific exploration has led to the investigation of plasma lensing as a potential solution for optical matching devices for all kinds of positron sources. This research becomes increasingly significant as the need for higher data output demands innovative concepts to increase positron yield and therefore luminosity. Instabilities were observed during the first test trials. This poster presents the results of high-temporal resolution imaging to analyse the discharge instabilities. Furthermore, the results show not expected but interesting insights and challenges. Overcoming these challenges is pivotal for a future application of plasma lenses as an integral part of high-performance positron sources.
Paper: MOPR39
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPR39
About: Received: 15 May 2024 — Revised: 11 Jun 2024 — Accepted: 11 Jun 2024 — Issue date: 01 Jul 2024
MOPR43
Experimental characterization of the timing-jitter effects on a beam-driven plasma wakefield accelerator
553
Plasma wakefield acceleration is nowadays very attractive in terms of accelerating gradient, able to overcome conventional accelerators by orders of magnitude. However, this poses very demanding requirements on the accelerator stability to avoid large instabilities on the final beam energy. In this study we analyze the correlation between the driver-witness distance jitter (due to the RF timing jitter) and the witness energy gain in a plasma wakefield accelerator stage. Experimental measurements are reported by using an electro-optical sampling diagnostics with which we correlate the distance between the driver and witness beams prior to the plasma accelerator stage. The results show a clear correlation due to such a distance jitter highlighting the contribution coming from the RF compression.
Paper: MOPR43
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPR43
About: Received: 14 May 2024 — Revised: 20 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPR66
Progress on the capillary plasma discharge source at UCLA
587
At UCLA, a plasma source using capillary discharge has been developed and studied for its potential use in plasma wakefield experiments at MITHRA and AWA facilities. This compact, 8-cm long source, has the ability to create plasmas covering a wide range of densities, making it suitable for various experiments involving plasma wakefield acceleration (PWFA). With a 3-mm aperture, it can transmit high-aspect ratio beams, and its adjustable density feature allows for a detailed exploration of the shift from linear to nonlinear PWFA stages. In this paper, we will delve into the construction and evaluation of this capillary discharge plasma source, as well as the utilization of an interferometric diagnostic system for measuring plasma density.
Paper: MOPR66
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPR66
About: Received: 17 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
MOPR68
Development of liquid lithium target in crucible for laser ion source
595
A liquid lithium target system is being developed for laser ion sources. Existing laser ion sources are operated at the repetition rate of the order of 1 Hz. The limitation stems from the use of solid laser targets because of the craters created and the need to provide a fresh surface by either repositioning the laser beam or the target. In addition, an enormously large surface area is needed for long-term operation. This limits the total yield of lithium ions and the application of laser ion sources. To dramatically increase the repetition rate, we propose the use of a liquid lithium target in a crucible because a liquid surface shape is recovered by itself after laser irradiation. The establishment of a liquid target system is an important objective for the development of the intense lithium beam driver for a clean compact source of a directional neutron beam. In the conference, the concept and design of experimental apparatus for the development will be presented.
Paper: MOPR68
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPR68
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
MOPR71
An ultimate single-ion source using a Coulomb crystal in a Paul trap
606
An ion cloud confined in a Paul trap eventually reaches a Coulomb crystalline state when strongly cooled toward absolute zero. The normalized emittance of the Coulomb crystal can be in the sub-femtometer range. The trap is thus usable as a unique ion source for nano-beam production, though the available beam intensity is limited. This new concept was first discussed nearly 20 years ago* and later experimentally demonstrated by several research groups (**, ***). In this paper, we report on the result of a recent experiment where an attempt was made to extract Ca+ or N2+ ions one by one from a compact linear Paul trap. In addition to the regular extraction scheme based on a string Coulomb crystal, the possibility of using a multi-shell crystalline structure is explored in detail.
Paper: MOPR71
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPR71
About: Received: 15 May 2024 — Revised: 18 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
MOPR86
Empirical modeling of the photocurrent time-dependence in co-deposition activation procedures for GaAs photocathodes
656
GaAs-based photocathodes can provide electron beams with high spin-polarization. In order to be used in a photo-gun for high-current applications such as energy-recovery linacs and colliders, the quantum efficiency as well as the lifetime of the photocathode needs to be as high as possible. Both parameters depend on the quality of the thin layer that is applied to the photocathode surface during the so-called activation process in order to create negative electron-affinity conditions for optimal photoemission. Hence, it is of great interest to optimize and standardize this procedure in order to provide the best possible photocathode performance for accelerator applications. For an automatization of the activation process it is necessary to model the photocurrent as a function of time during the process. To this end, activations of bulk-GaAs using Cs and O, conducted at the Photo-CATCH test stand, were analyzed using an empirical model function. This contribution presents the results of the analysis and its implications regarding the influence of the activation process on the performance of the activated photocathode.
Paper: MOPR86
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPR86
About: Received: 15 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
MOPR89
Framework for a multiphysics model of optical field emission from extended nanostructures
664
Laser-field emission, or optical field emission, is a process that can produce electron beams with high charge density and high brightness with ultrafast response times. Using an extended nanostructure, such as a nanoblade, permits plasmonic field enhancement up to 80 V/nm with an incident ultrafast laser of wavelength 800 nm. Stronger ionizing fields lead to higher current densities, so understanding how this field is attained will aid in further increasing brightness. In this paper we lay the framework to study the nanoblade system thermomechanically and plasmonically. We show that, in the moving frame following the laser driver, a steady state is reached, allowing us to reduce the computational complexity of the multiphysics calculation. We derive Maxwell's equations and the current dynamical equation for the steady state in such a moving frame. We also derive the eigenproblem for finding plasmonic modes in the structure with a nonlinear dielectric. The planned calculations to come will allow us to predict peak attainable fields and optimal experimental parameters. We leave off with a discussion of directions for numerical implementation.
Paper: MOPR89
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPR89
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
MOPR91
Particle motion in spatio-spectrally iso-diffracting ultrabroadband pulsed beams
672
An analytical form is derived using the Faddeeva function to represent terahertz-frequency pulses generated by optical rectification of ultrashort laser pulses. Spectra of these pulses can be described by a Gaussian fall-off at high frequencies and a power-law as DC is approached. A set of pulsed beams based on this form is also derived for the special case of propagation-invariant spatio-temporal coupling (iso-diffracting). Motion of charged particles in these pulsed beams is considered analytically and numerically and energy gain is computed and compared with ponderomotive force laws. Particle motion in more complex pulsed-beam fields is also considered.
Paper: MOPR91
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPR91
About: Received: 15 May 2024 — Revised: 22 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPR92
Evaluation of ultrafast THz near-fields for electron streaking
675
THz-frequency accelerating structures could provide the accelerating gradients needed for compact next generation particle accelerators. One of the most promising THz generation techniques for accelerator applications is optical rectification in lithium niobate using the tilted pulse front method. However, accelerator applications are limited by losses during transport and coupling of THz radiation to the acceleration structure. Applying the near-field of the lithium niobate source directly to the electron bunch removes losses due to transport and coupling, yielding a simplified and efficient system. Using electro-optic sampling we have reconstructed the full temporal 3D THz near-field close to the lithium niobate emission face and shown that it can be controlled by manipulating the generation setup. Analysis of the results of this measurement shows an estimated peak field strength of 86 MV/m. A future THz near-field electron streaking experiment is currently planned as a first test of manipulating an electron bunch with the THz near field. Analysis for this planned experiment has yielded an estimated THz near-field kick strength of 23 keV.
Paper: MOPR92
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPR92
About: Received: 15 May 2024 — Revised: 28 May 2024 — Accepted: 28 May 2024 — Issue date: 01 Jul 2024
MOPS07
Classification of potentials for self consistent symplectic space charge
702
A general theory of symplectic tracking under the influence of space charge force is not yet available, even if some specific solution was proposed [1, 2]. In this paper we will first review how the pull-back of the Lie transform can be used to self-transport the beam distribution and its associated electromagnetic potential under the effect of the space-charge. We will then classify the functions suitable for an iterative algorithm with the Lie transform. Those functions will be used to describe the electromagnetic potential of the space charge.
Paper: MOPS07
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS07
About: Received: 14 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
MOPS08
Advancing non-linear space charge simulations: neural networks and analytical approaches
705
This study explores various neural network approaches for simulating beam dynamics, with a particular focus on non-linear space charge effects. We introduce a convolutional encoder-decoder architecture that incorporates skip connections to predict transversal electric fields. The model demonstrates robust performance, achieving a root mean squared error (RMSE) of $0.5\%$ within just a few minutes of training. Furthermore, this paper explores the feasibility of replacing traditional ellipsoidal methods with Gaussian envelope models for improved non-linear space-charge calculations. Our findings indicate that these advancements could provide a more efficient alternative to numerical space-charge methods in beam dynamics simulations.
Paper: MOPS08
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS08
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPS09
Benchmark of AT vs MADX-PTC with exact integrators
709
Recently exact Hamiltonian integrators have been added for drift, multipoles and dipoles in Accelerator Toolbox. This paper reports the tracking simulations benchmarks performed to compare with the results provided by MADX-PTC for four lattices: FODO, DBA, H7BA and FCC-HFD@Z. Tracking times are also reported for completeness. The agreement in 4D is complete while small discrepancies persist for 6D tracking. Fringe fields models were not included in the comparison and are known to be different for the two codes.
Paper: MOPS09
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS09
About: Received: 10 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPS10
Koopman operator method for nonlinear dynamics analysis using symplectic neural networks
713
Data driven methods have proved to be a useful tool for analyzing Hamiltonian systems. The symplectic condition is a strong constraint on Hamiltonian systems and it is therefore useful to implement this constraint into neural networks to ensure the accuracy of long term predictions about the system. One such method is the use of SympNets*, linear, activation, and gradient layers that guarantee the symplectic condition is met without the use of symplectic integration or extra gradient calculations. Data driven methods are also useful for calculating Koopman operators which aim to simplify nonlinear dynamical systems into linear ones. By using SympNets, one can ensure that the transformation described by the Koopman operator is symplectic, reversible, and more easily trained.
Paper: MOPS10
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS10
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPS11
Dynamics study of the crab crossing at the electron ion collider using square matrix and iterative methods
717
Crab crossings are designed to increase the luminosity of accelerators by ensuring beam interactions are closer to a head on collision. One will be implemented at the Electron Ion Collider (EIC) at Brookhaven National Laboratory. It is then important to examine how the crab cavity will affect beam dynamics at the EIC. Methods such as Frequency Map Analysis (FMA) have been shown to be helpful in examining the phase space of accelerators in order to find properties such as resonances and the dynamic aperture. An alternative to such methods is an iterative method based on square matrix method that has been shown to reveal similar properties as FMA while reducing the computational power needed*,**. This method has been applied to the crab crossing scheme in order to find and explain effects of the higher order mode of crab cavities on the particle dynamics of the EIC.
Paper: MOPS11
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS11
About: Received: 15 May 2024 — Revised: 22 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPS18
Expansions of the integrability program for novel accelerators
744
The physical realization of integrable Hamiltonian dynamics provides promising avenues for investigations of new particle accelerators, best demonstrated by the Integrable Optics Test Accelerator (IOTA) at Fermilab. The core concept of IOTA centers around the results of the Danilov-Nagaitsev paper, where taking the paraxial approximation of the Hamiltonian for a charged particle can lead to a completely integrable system for a charged particle in the transverse plane. However, certain generalizations of that paper fail to provide similar results. We provide insights into some reasons for failure, as well as discuss a set-up for establishing a 6D integrable Hamiltonian system, in order to include the possibility of acceleration.
Paper: MOPS18
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS18
About: Received: 13 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
MOPS26
Macro-particle simulations of longitudinal peak-detected Schottky signals
767
The peak-detected Schottky system is a powerful diagnostic tool for observing the longitudinal beam parameters. According to the theoretical model, the peak value of the signal from a wide-band pick-up contains information on particle distribution as a function of the synchrotron frequency. Due to intrinsic assumptions needed for modelling the acquisition set-up and uncertainties in beam parameters, a one-to-one comparison of predictions and measurements remains a challenge. We obtained, for the first time, the peak-detected Schottky spectra in macro-particle simulations for a simplified experimental set-up. Following refinement of the theoretical model, a direct comparison was performed under controlled conditions. Agreement with the numerical results was improved by introducing an additional form factor describing the probability of a particle being present in the observation window. Modifications due to collective effects are briefly discussed as well.
Paper: MOPS26
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS26
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
MOPS30
High-performance magnet simulation software
778
We present a high-performance solver for the magnetostatic equations. The solver can simulate nonlinear and anisotropic magnetic materials on a highly variable grid, enabling efficient resolution of fine features even in very large systems. It is built on the Tpetra parallel sparse linear algebra package, allowing it to handle problems with billions of degrees of freedom and employ hardware acceleration with Nvidia graphics processing units. Integration into the VSim electromagnetics software allows users to design magnetic systems using existing graphical interface features. Example simulations of nonlinear magnets, with application to particle accelerator magnet design, will be shown.
Paper: MOPS30
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS30
About: Received: 22 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPS33
Single-bunch instabilities and their mitigation in Diamond-II
786
Diamond-II is a future 4-th generation synchrotron light source with a significantly narrower vacuum chamber compared to the existing Diamond storage ring. The strength of wake fields will increase, and, consequently, the risk of single-bunch instabilities also rises. We consider chromaticity adjustment and a passive harmonic cavity as mitigation measures, including for cases with impedance strength larger than the design value. This work presents single-bunch thresholds obtained in particle tracking simulations for the latest lattice and impedance database, including the case of non-equal bunch lengthening in realistic filling patterns due to beam loading in the RF cavities. The impedance database includes accurate computations of asymmetric vessels causing non-zero monopole and quadrupole components of the wake. Resulting emittance dilution due to impedance is found to be tolerable.
Paper: MOPS33
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS33
About: Received: 15 May 2024 — Revised: 16 May 2024 — Accepted: 16 May 2024 — Issue date: 01 Jul 2024
MOPS37
Development of numerical tools for intra-beam scattering modelling
802
Intra-beam Scattering (IBS) is one of the main mechanisms of emittance blowup and performance deterioration in the Large Hadron Collider (LHC) accelerator complex. It is particularly relevant since the recent upgrades across the injector complex to reach the high brightness beams of the High Luminosity LHC (HL-LHC) era have been implemented. Several studies have focused on developing an accurate formalism to describe IBS, and the integration of IBS in codes such as, e.g. MAD-X, is widely used in the accelerator physics community. This study presents the latest developments of a Python package for IBS simulations, recently developed at CERN, meant for integration with the Xsuite ecosystem. The new capabilities of the Python code are detailed and a thorough benchmark against existing codes is presented, for various machines of the CERN accelerator complex in different configurations.
Paper: MOPS37
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS37
About: Received: 08 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
MOPS41
A novel coherent synchrotron radiation simulation method using cavity Green's functions
814
The mitigation of collective beam effects, in particular Coherent Synchrotron Radiation (CSR), is crucial for the development of particle accelerators with higher beam brightness. Among the strategies proposed in the literature, the use of appropriate shielding walls to curb CSR is an attractive strategy with many associated open problems. In particular, simulation methods that account for shielding effects usually employ image charges and assume free space potentials, making them only applicable for simple wall layouts. In this work, we will outline a novel simulation technique that makes use of cavity Green's functions to capture the field modes admitted by the shielding walls. In addition to better resolving the radiated fields, the proposed method will be robust to singularities that are typically encountered in the image charge approach. We will discuss the computational implications of using cavity Green's functions and discuss strategies to scale the method to complex geometries and large particle counts. The method will eventually be validated using results from a planned shielding study at the Argonne Wakefield Accelerator using a dipole chamber with variable gap size.
Paper: MOPS41
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS41
About: Received: 15 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
MOPS47
Unifying coherent synchrotron radiation wakefield and classical radiation reaction
825
We develop an alternative theory of coherent synchrotron radiation (CSR) wakefield using the transverse field solution of Maxwell equations in angular domain. This approach allows us to retain only the radiative interaction between particles and cure the frequently encountered divergence in retarded potentials. We analyze the classical radiation reaction force and mass renormalization induced by the CSR self-field. Futhermore, we illustrate our theory by explicitly calculating the steady-state CSR wakefield of a wiggler.
Paper: MOPS47
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS47
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
MOPS59
Fast-ramping alpha magnet for interleaved operation at ANL APS
856
RadiaBeam is designing and manufacturing a fast-ramping alpha magnet is developed for interleaved operation at the Argonne Advanced Photon Source (APS). This interleaving operation requires the alpha magnet to stably complete a 5 s long cycle with a 100 ms ramp-up, 1000 ms nominal field output and a 100 ms ramp-down. A laminated yoke is used to minimize eddy currents, ensure fast field response times and reduce core-loss during operation. The magnetic and mechanical design demonstrating the performance of this 2.75 T/m maximum field gradient alpha magnet within a 10 cm x 14 cm good field region will be presented along with the current fabrication status.
Paper: MOPS59
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS59
About: Received: 15 May 2024 — Revised: 28 May 2024 — Accepted: 28 May 2024 — Issue date: 01 Jul 2024
MOPS61
Change of Hamiltonian during longitudinal separatrix crossing
860
Near-adiabatic capture into an RF bucket with rising voltage has been used since 1946 or earlier. But until the present work, there is no analytic and deterministic description of the process capable of predicting the final phase space distribution (for arbitrary voltage ramps). Recently, we have developed formulae for trajectories that cross the instantaneous separatrix, and the corresponding change of Hamiltonian. Previous attempts at this calculation were unsatisfactory: either plagued by singularities, or limited to probabilistic results for linear variation of the confining potential. Previously*, we presented formulae for the changes in Hamiltonian (due to modulation and bunching) before and after separatrix crossing; and those contributions to emittance growth are equally or more important. Together, the three results provide a complete, analytic description of near-adiabatic capture into an RF bucket.
Paper: MOPS61
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS61
About: Received: 03 May 2024 — Revised: 23 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
MOPS65
Enhancing CERN-SPS slow extraction efficiency: meta Bayesian optimisation in crystal shadowing
870
The Super Proton Synchrotron at CERN serves the fixed-target experiments of the North Area, providing protons and ions via slow extraction, and employs the crystal shadowing technique to significantly minimize losses. Over the past three operational years, the use of a crystal, positioned upstream of the electrostatic septum to shadow its blade, has allowed to achieve a 25% reduction in losses. Additionally, a novel non-local shadowing technique, utilizing a different crystal location, has successfully halved these losses. While using a single crystal in this location resulted in a temporary 50% reduction in slow extraction losses at nominal intensity, this effect was not sustainable beyond a few hours. This limitation is primarily attributed to the magnetic non-reproducibility and hysteresis inherent to the SPS main dipoles and quadrupoles. In this paper, we introduce the application of the Rank-Weighted Gaussian Process Ensemble to the setup of shadowing. We demonstrate its superior efficiency and effectiveness in comparison to traditional Bayesian optimization and other numerical methods, particularly in managing the complex dynamics of local and non-local shadowing.
Paper: MOPS65
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS65
About: Received: 08 May 2024 — Revised: 22 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPS66
First operational experience with data-driven hysteresis compensation for the main dipole magnets of the CERN SPS
874
Magnetic hysteresis, eddy currents, and manufacturing imperfections pose significant challenges for beam operation in multi-cycling synchrotrons. Addressing the dynamic dependency of magnetic fields on cycling history is a current limitation for control room tools using existing models. This paper outlines recent advancements to solve this, presenting the outcome of operational tests utilizing data-driven approaches and an overview of the next steps. Notably, artificial neural networks, including long short-term memory networks, transformers and other time series analysis architectures, are employed to model static and dynamic effects in the main dipole magnets of the CERN SPS. These networks capture hysteresis and eddy current decays based on measured magnetic field and data from the real-time magnetic measurement system of the SPS main dipoles. Cycle-by-cycle feed-forward corrections are implemented through the CERN accelerator controls infrastructure, which propagate corrections of magnetic fields to corresponding adjustments in the current of the power converters feeding the magnets.
Paper: MOPS66
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS66
About: Received: 14 May 2024 — Revised: 18 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
MOPS67
Experimental verification of integrability in a Danilov-Nagaitsev lattice using machine learning
878
In non-linear optics, achieving integrability can enhance the dynamic aperture in storage rings. We analyze turn-by-turn phase-space data from our Danilov-Nagaitsev lattice implementation at Fermilab's Integrable Optics Test Accelerator using machine learning. AI Poincaré estimates conserved quantities from experimental data without prior knowledge of the invariant structure, showing qualitative agreement with theoretical predictions. Additionally, one of the two learned invariants exhibits comparable or better conservation compared to known theoretical expressions.
Paper: MOPS67
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS67
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPS69
Harnessing machine learning for the optimal design of ILC e-driven positron source
886
The International Linear Collider (ILC) is a next-generation electron-positron collider designed to operate at center-of-mass energies ranging from 250 GeV to 1 TeV, providing opportunities for exploring physics beyond the Standard Model. A critical component of the ILC is the E-driven positron source, which requires sophisticated technology to produce large quantities of positrons. Traditional accelerator design methods involve sequential optimization, which is inefficient and challenging for achieving global optimization. This study introduced the use of the Tree-structured Parzen Estimator (TPE) algorithm, a black-box optimization method, to improve the design efficiency of the ILC E-driven positron source. By implementing the TPE algorithm using Optuna, we optimized up to 8 parameters, achieving a positron capture efficiency of 1.42, significantly higher than the 1.20 efficiency obtained through manual optimization. This substantial improvement is expected to meet the safety standards for target destruction. The optimization process was also expedited, reducing the time from about a week to approximately half a day. These results demonstrate the potential of machine learning techniques in accelerator design, offering a more comprehensive global optimization by exploring a broader parameter space and avoiding local minima.
Paper: MOPS69
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS69
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPS72
Solving the Orszag-Tang vortex magnetohydrodynamics problem with physics-constrained convolutional neural networks
897
The 2D Orszag-Tang vortex magnetohydrodynamics (MHD) problem is studied through the use of physics-constrained convolutional neural networks (PCNNs). The density and the magnetic field are forecasted, and we also predict magnetic field given the velocity field of the fluid. We examined the incorporation of various physics constraints into the PCNNs: absence of magnetic monopoles, non-negativity of density and use of only relevant variables. Translation equivariance was present from the convolutional architecture. The use of a residual architecture and data augmentation was found to increase performance greatly. The most accurate models were incorporated into the simulation, with reasonably accurate results. For the prediction task, the PCNNs were evaluated against a physics-informed neural network (PINN), which had the ideal MHD induction equation as a soft constraint. The use of PCNNs for MHD has the potential to produce physically consistent real-time simulations to serve as virtual diagnostics in cases where inferences must be made with limited observables.
Paper: MOPS72
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS72
About: Received: 13 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
MOPS73
Utilizing neural networks to speed up coherent synchrotron radiation computations
901
Coherent synchrotron radiation has a significant impact on electron storage rings and bunch compressors, inducing energy spread and emittance growth in a bunch. While the physics of the phenomenon is well-understood, numerical calculations are computationally expensive, severally limiting their usage. Here, we explore utilizing neural networks (NNs) to model the 3D wakefields of electrons in circular orbit in the steady state condition. We demonstrate that NNs can achieve a significant speed-up, while also accurately reproducing the 3D wakefields. NN models were developed for both Gaussian and general bunch distributions. These models can potentially aid in the design and optimization of accelerator apparatuses by enabling rapid searches through parameter space.
Paper: MOPS73
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS73
About: Received: 13 May 2024 — Revised: 19 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
MOPS74
Accelerator system parameter estimation using variational autoencoded latent regression
905
A particle accelerator is a time-varying complex system whose various components are regularly perturbed by external disturbances. The tuning of the accelerator can be a time-consuming process involving manual adjustment of multiple components, such as RF cavities, to minimize beam loss due to time-varying drifts. The high dimensionality of the system (~100 amplitude and phase RF settings in the LANSCE accelerator) makes it difficult to achieve optimal operation. The time-varying drifts and the dimensionality make system parameter estimation a challenging optimization problem. In this work, we propose a variational autoencoded latent regression (VAELR) model for robust estimation of system parameters using 2D unique projections of a charged particle beam's 6D phase space. In VAELR, VAE projects the phase space projections into a lower-dimensional latent space, and a dense neural network maps the latent space onto the space of system parameters. The trained network can predict system parameters for unseen phase space projections. Furthermore, VAELR can generate new projections by randomly sampling the latent space of VAE and also estimate the corresponding system parameters.
Paper: MOPS74
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS74
About: Received: 14 May 2024 — Revised: 21 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPS75
Towards latent space evolution of spatiotemporal dynamics of six-dimensional phase space of charged particle beams
909
Addressing the charged particle beam diagnostics in accelerators poses a formidable challenge, demanding high-fidelity simulations in limited computational time. Machine learning (ML) based surrogate models have emerged as a promising tool for non-invasive charged particle beam diagnostics. Trained ML models can make predictions much faster than computationally expensive physics simulations. In this work, we have proposed a temporally structured variational autoencoder model to autoregressively forecast the spatiotemporal dynamics of the 15 unique 2D projections of 6D phase space of charged particle beam as it travels through the LANSCE linear accelerator. In the model, VAE embeds the phase space projections into a lower dimensional latent space. A long-short-term memory network then learns the temporal correlations in the latent space. The trained network can evolve the phase space projections across further modules provided the first few modules as inputs. The model predicts all the projections across different modules with low mean squared error and high structural similarity index.
Paper: MOPS75
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS75
About: Received: 14 May 2024 — Revised: 23 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
MOPS79
Modeling and optimization of the FACET-II injector with machine learning algorithms
913
Linear particle accelerators are elaborate machines that demand a thorough comprehension of their beam physics interactions to enhance performance. Traditionally, physics simulations model the physics interactions inside a machine but they are computationally intensive. A novel solution to the long runtimes of physics simulations is replacing the intensive computations with a machine learning model that predicts the results instead of simulating them. Simple neural networks take milliseconds to compute the results. The ability to make physics predictions in almost real time opens a world of online models that can predict diagnostics which typically are destructive to the beam when measured. This research entailed the incorporation of an innovative simulation infrastructure for the SLAC FACET-II group, aimed at optimizing existing physics simulations through advanced algorithms. The new infrastructure saves the simulation data at each step in optimization and then improves the input parameters to achieve a more desired result. The data generated by the simulation was then used to create a machine learning model to predict the parameters generated in the simulation. The machine learning model was a simple feedforward neural network and showed success in accurately predicting parameters such as beam emittance and bunch length from varied inputs.
Paper: MOPS79
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS79
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUBD3
Analyzing sudden beam loss in the SuperKEKB/Belle-II experiment with RFSoC technology
959
In the SuperKEKB/Belle-II experiment, a multitude of elementary particle reactions is initiated through the collision of 4 GeV positrons with 7 GeV electrons, paving the way for the exploration of new physics. The experiment includes plans for the substantial enhancement of luminosity in the future, aiming to achieve an integrated luminosity approximately 100 times the current level. However, the realization of this goal is impeded by a recurrent occurrence of a phenomenon known as "Sudden Beam Loss," which entails the abrupt disappearance of the beam within tens of microseconds. The cause and location of these occurrences have not yet been identified. To provide the tools to diagnose and debug these sudden beam loss events, a new Bunch Oscillation Recorder (BOR) has been developed to analyze this phenomenon, utilizing the Radio Frequency System on Chip (RFSoC) from AMD/Xilinx. The beam position of each individual bunch is measured and recorded by the BOR just prior to the onset of sudden beam loss. We will present how the signal from the button beam position monitor of the beam pipe is processed by RFSoC, along with the results obtained from observing the actual SuperKEKB beam using RFSoC.
Paper: TUBD3
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUBD3
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
TUCN3
Results from CXLS commissioning
981
The Compact X-ray Light Source (CXLS) is a compact source of femtosecond pulses of x-rays that is now commissioning in the hard x-ray energy range 4-20 keV. It collides the beams from recently developed X-band distributed-coupling, room-temperature, standing-wave linacs and photoinjectors operating at 1 kHz repetition rates and 9300 MHz RF frequency, and recently developed Yb-based lasers operating at high peak and average power to produce fs pulses of 1030 nm light at 1 kHz repetition rate with pulse energy up to 200 mJ. These instruments are designed to drive a user program in time-resolved x-ray studies such as SAXS/WAXS, XES and XAS, femtosecond crystallography as well as imaging. The different technical systems also act as prototypes for the more advanced CXFEL discussed elsewhere in these proceedings. We present the performance of the CXLS technical components and initial x-ray results.
Paper: TUCN3
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUCN3
About: Received: 20 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPC04
ATF2-3 hardware upgrade and new experimental results to maximize luminosity potential of linear colliders
996
The ATF2-3 beamline is the only facility in the world for testing the Final Focus Beamline of linear colliders and is essential for the ILC and the CLIC projects. A vertical electron beam size of 41 nm (within 10% of the target), a closed-loop intra-bunch feedback of latency 133 ns, and direct stabilization of the beam position at the Interaction Point to 41 nm (limited by IP BPM resolution) have all been achieved at ATF2. These results fulfilled the two main ATF2 design goals, but were obtained with reduced aberration optics and a bunch population of approximately 10% of the nominal value of 10^10 electrons. Recent studies indicate that the beam degradation with the beam intensity is due to the effects of wakefields. To overcome this intensity limitation, hardware upgrades including new vacuum chambers, magnets, IP-Beam Size Monitor laser, cavity BPMs, wakefield mitigation station, as well as a comprehensive R&D program to maximize the luminosity potential are being pursued in the framework of the ILC Technology Network. This new R&D program focuses on the study of wakefield mitigation techniques, correction of higher-order aberrations, tuning strategies, including AI techniques, as well as beam instrumentation issues, such as the BPMs, advanced Cherenkov Diffractive Radiation monitors, and fast feedback systems, among others. This paper summarizes the hardware upgrades, the R&D program and the results of the Fall 2023-Winter 2024 experimental campaign performed in ATF2-3.
Paper: TUPC04
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPC04
About: Received: 15 May 2024 — Revised: 29 May 2024 — Accepted: 29 May 2024 — Issue date: 01 Jul 2024
TUPC06
Dynamic aperture of the RCS during bunch merges
1003
The Rapid Cycling Synchrotron (RCS) of the Electron Ion Collider (EIC) will be used to accelerate polarized electrons from 400 MeV to a top energy of 5, 10, or 18 GeV before injecting into the Electron Storage Ring. At 1 GeV, the RCS will perform a merge of two bunches into one, adding longitudinal dynamics that effects the dynamic aperture, depending on the merge parameters. In this paper, results for different merge models will be compared, as well as finding the relationship between the merge parameters of the RCS and its dynamic aperture.
Paper: TUPC06
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPC06
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPC10
RF system upgrade for 1.3 MW operation of J-PARC main ring
1017
The J-PARC Main Ring accelerates proton beam from 3 GeV to 30 GeV and delivers it to T2K neutrino experiment with fast extraction and hadron experiments with slow extraction. In the last two years the beam power to the neutrino experiment was increased from 500 kW to 750 kW. The T2K detector is scheduled to be replaced by the new Hyper-K detector; the latter will be able to accept a 1.3 MW proton beam by 2028. To achieve 1.3 MW beam power, J-PARC plans to upgrade the Main Ring by increasing intensity and repetition rate. The Main Ring uses low frequency, high bandwidth RF cavities with Magnetic Alloy cores, powered by two 600 kW tetrode tubes. Under the upgrade plan, the number of RF cavities will be increased to secure the RF voltage and longitudinal acceptance. The anode power supply will be upgraded to provide enough current for both gap voltage and beam loading compensation. The upgraded LLRF system will be optimized to control fundamental and 2nd harmonic RF voltages, suppress coupled bunch instabilities and compensate beam loading effects. Current operational status as well as details of the upgrade plan and related simulation results will be discussed in this paper.
Paper: TUPC10
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPC10
About: Received: 20 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
TUPC12
Study on beam injection and ramping efficiency for Korea-4GSR booster synchrotron
1025
The Korea fourth-generation storage ring (Korea-4GSR) project was launched in 2021 to generate high-brightness photon beams as a diffraction-limited light source. The 200 MeV beam is injected into the booster synchrotron. The beam parameters and transmission efficiency fluctuate with initial beam conditions such as beam Twiss parameters and centroid offsets during the injection and energy ramping process. Therefore, the study on the initial conditions of the incident beam to the booster synchrotron needs to be carried out to gain high beam quality and efficiency. This paper presents the energy ramping results of the beams injected into the booster synchrotron with various initial beam conditions.
Paper: TUPC12
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPC12
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
TUPC14
Application and comparative analysis of the APES_CBI module in BEPC-II experimental results
1033
In this paper, we delve into the application and comparative analysis of the Accelerator Physics Emulation System Cavity-Beam Interaction (APES_CBI) module within the BEPC-II (Beijing Electron-Positron Collider) experiments. We developed the APES_CBI module as an advanced time-domain solver, specifically designed to analyze RLC circuits driven by beam and generator currents and to simulate the dynamic responses and synchrotron oscillations of charged particles within the cavity. We begin by discussing our method for solving RLC parallel circuits, followed by an explanation of the logical architecture of our program. In the second part, we detailed our simulation results, starting with the BEPC-II electron ring. By comparing these results with experimental data, we validate the reliability of our simulations, showcasing our module's ability. Additionally, we extend our simulations to the CEPC Higgs mode on-axis injection conditions and studied the transient phase response to the sudden change of beam pattern.
Paper: TUPC14
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPC14
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPC15
Energy dependence of PS main unit harmonics
1036
CERN Proton Synchrotron (PS) is featured with 100 C-shaped combined-function Main Units (MUs) magnets with a complicated pole shape. The operation and the modelling of the PS-MUs has been historically carried out with empirical beam-based studies. However, it would be interesting to understand whether, starting from a proper magnetic model and using the predicted harmonics as input to optics simulations, it is possible to accurately predict the beam dynamics behavior in the PS, and assess the model accuracy with respect to beam-based measurements. To evaluate the magnetic model quality and its predictions, bare-machine configurations at different energies were prepared, where only the Main Coil is powered and the additional circuits are off. In this paper, a comparison of tunes and chromaticity measurements with the predicted optics is reported, showing the saturation of the quadrupolar and sextupolar components at high energy, which affect these quantities.
Paper: TUPC15
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPC15
About: Received: 13 May 2024 — Revised: 23 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
TUPC37
Development of a fast pulsed magnet system for the MYRRHA collaboration
1084
In the framework of the MYRRHA programme, a large-scale Accelerator Driven System (ADS) being implemented by SCK CEN in Belgium, a fast pulsed magnet system is being designed and specified at CERN. A complete design study has been performed to develop the specifications and drawings for a kicker magnet, as well as the associated pulse generator to deflect the 100 MeV proton beam. This paper outlines the numerical simulations that have been set up to evaluate the performance of the kicker magnet featuring a 5 μs rise time with a variable flat top of 10 μs to 500 μs and a 250 Hz repetition rate. The design study concluded on a water-cooled lumped inductance magnet with two half coils each of 2 turns featuring a magnet aperture of 90 mm x 57 mm. The outside vacuum magnet design requires a coated ceramic vacuum chamber to pass the fast kicker field of 17.3 mT. The associated pulse generator has been designed to deliver pulses of 2 kV and 200 A matching the kicker rise time and is outlined together with the cable choice.
Paper: TUPC37
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPC37
About: Received: 08 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
TUPC38
SPS injection kicker system: 2023 operational experience and upgrade proposals for high-luminosity LHC
1088
The SPS injection kicker system comprises twelve MKP-S (small aperture) modules and four MKP-L (large aperture) modules. An upgraded MKP-L magnet was installed in the SPS, during December 2022, in view of the higher beam intensity needed in the future for High-Luminosity-LHC. The upgrades have significantly reduced the beam coupling impedance and consequent beam induced heating. The improved performance is due to a new beam screen, consisting of silver fingers painted on an alumina chamber, inserted in each magnet’s aperture. Additionally, a surface coating on the chamber's inner surface reduces its secondary electron yield and hence dynamic vacuum activity. The effectiveness of these upgrades was demonstrated during the 2023 operation. This paper provides an in-depth exploration of the initial year of operational experience with the upgraded MKP-L, giving a comparative analysis of dynamic vacuum and beam induced heating with the MKP-S modules. An alternative approach for upgrading the MKP-S modules, to reduce their temperature, is also proposed.
Paper: TUPC38
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPC38
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
TUPC47
SoC based time-resolved scaler DAQ and amplifier-discriminator upgrade for laser spectroscopy
1115
The BEam COoler and LAser spectroscopy (BECOLA) is a collinear laser spectroscopy facility at the Facility for Rare Isotope Beams (FRIB) at Michigan State University. Time resolved laser spectroscopy experiments are performed here to study the nuclear structure of radioactive isotopes. The current data acquisition (DAQ) system being used is based on AMD Spartan 6 field programmable gate array (FPGA) and has a time resolution of 8 ns. There was a need to upgrade existing hardware to meet the requirements for higher time resolution of fast ion detectors. A new DAQ system with AMD Zynq System on Chip (SoC) FPGA based time-resolved scaler was designed, developed and fabricated. It achieves a time resolution of 2 ns. The current amplifier-discriminator has an output pulse resolution of 10 ns. To address this constraint and fully leverage the 2 ns time resolution provided by the new SoC FPGA, a new AD with an output pulse resolution of 1 ns was designed. A brief overview of the upgraded DAQ system will be discussed in this paper, including its features, improvements and future updates.
Paper: TUPC47
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPC47
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPC61
Applications of horizontal field damping wiggler in the diffraction limited storage ring
1136
In this study, we present a lattice design for the dif-fraction limited storage ring (DLSR), achieving an ultra-low natural emittance of 25.6 pm·rad (N-IBS). To address the significant intra-beam scattering (IBS) effect resulting from the ultra-low emittance and long damping times, Horizontal Field Damping Wigglers (HFDWs) have been adopted. These components de-crease damping times and beam horizontal emittance while generating vertical emittance, thereby achieving a "round beam" in the 864mDLSR. Using theoretical analysis and accelerator toolbox simulations, the op-timal peak field, period length, and overall length of the HFDWs for the 864mDLSR have been determined. In addition, the linear optical corrections were per-formed on both the front and rear units of the HFDWs using six quadrupoles.
Paper: TUPC61
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPC61
About: Received: 14 May 2024 — Revised: 16 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
TUPG01
Dismantle, assembly and installation plans for the ALBA II upgrade
1217
The 3.0 GeV ALBA Synchrotron Light Source, in operation with users since 2012, is looking forward an upgrade aimed at enhancing the brightness and coherence fraction of the delivered X-ray beam. The Storage Ring (SR) will be completely renewed but we plan on keeping the same orbit length and the position of the ID source points. The energy of the electrons will be preserved and the same injector will be used. Major part of the Insertion Devices and Front Ends will be kept; new ones will feed additional long Beamlines (230m-275m), included on the project. The “dark period” is foreseen for 2030-2031. This paper presents the strategic plans being developed to test and assemble the new SR components, the dismantling of the present SR and the seamless installation of the upgraded SR. Emphasizing a cost-effective and time-efficient approach, we have started the planning by focusing on optimizing spaces and equipment movements necessary for the upgrade process.
Paper: TUPG01
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG01
About: Received: 10 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
TUPG06
Particle accumulator ring restart and readiness for Advanced Photon Source upgrade commissioning
1228
At the Argonne (ANL) Advanced Photon Source (APS), a 425-MeV Particle Accumulator Ring (PAR) is used to stack 1-nC electron pulses from the linac and inject a single bunch into the booster at a 1-Hz repetition rate. All the APS injectors, including PAR, were shut down in April 2023 at the start of the APS Upgrade Dark Time. In this paper, we report on PAR re-start activities starting in Oct. 2023. The PAR vacuum pressure was unexpectedly high when first powering the fundamental and harmonic radiofrequency (rf) systems, as well as when first injecting the beam, which initially limited both the beam charge and rf gap voltage. These limits were overcome through many weeks of systematic rf and vacuum conditioning. Additional restart activities include commissioning two new kicker chambers with a special low-impedance, eddy-current-suppressing coating, commissioning of the digital low level rf system, and tests with the Injection Extraction Timing and Synchronization (IETS) system. We demonstrated initial APS-U commissioning performance goals: a stable, 5-nC injected bunch charge with a bunch length short enough for injection into the booster.
Paper: TUPG06
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG06
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPG07
APS upgrade booster commissioning
1232
After a long shutdown, the Advanced Photon Source (APS) booster synchrotron was recently re-commissioned for the APS Upgrade (APS-U) project. The APS-U requirements for the booster are more demanding than the old APS: much higher bunch charge, reduced beam emittance, and improved charge stability of better than 5% shot to shot. The booster accelerates electron bunches of 1-12 nC from 425 MeV to 6 GeV at a 1 Hz rep rate. While the booster ring hardware was largely kept the same, it is now run on a separate RF source, which allows for frequency manipulation during the booster ramp. Photon diagnostics have recently been upgraded for reduced thermal drift. This paper will report on the booster re-commissioning process, including checkout of various systems, tests of the new RF source, and tuning for improved performance. It will also detail plans for further improvements, in particular for achieving even higher bunch charge.
Paper: TUPG07
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG07
About: Received: 15 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
TUPG14
Beam centroid studies at the Canadian Light Source
1243
The Canadian Light Source (CLS) storage ring RF frequency varies on timescales of seconds to days. Over approximately 20 years it has drifted from its design value. We outline and discuss our efforts to identify, disentangle and mitigate the potential sources of variations in the RF frequency on various timescales. These sources include the building temperature regulation, the orbit correction algorithm and the dipole power supply. Further, orbit correction generates an undesirable amount of beam noise through the dispersion correction. We have ongoing efforts to understand and improve orbit correction and remove the noise it propagates into the RF frequency.
Paper: TUPG14
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG14
About: Received: 14 May 2024 — Revised: 21 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
TUPG25
Operation and developments at the ESRF-EBS light source
1270
The European Synchrotron Radiation Facility - Extremely Brilliant Source (ESRF-EBS) is a facility upgrade allowing its scientific users to take advantage of the first high-energy 4th generation storage ring light source. In December 2018, after 30 years of operation, the beam stopped for a 12-month shutdown to dismantle the old storage ring and to install the new X-ray source. On 25th August 2020, the user program restarted with beam parameters very close to nominal values. Since then beam is back for the users at full operation performance and with an excellent reliability. This paper reports on the present operation performance of the source, highlighting the ongoing and planned developments and the sustainability efforts.
Paper: TUPG25
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG25
About: Received: 10 May 2024 — Revised: 20 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPG26
Emittance blow-up with a magnetic shaker at different chromaticities
1274
The ESRF-EBS storage ring is operated with constant vertical emittance at 10 pm. The emittance blow-up is obtained with a magnetic shaker exciting the beam with a noise in a range of frequencies including the betatron tunes. The amplitude of the shaker is tuned by a feedback depending on the measured emittance. The coherent oscillations given to the beam by the shaker at each turn become incoherent thanks to the chromaticity and the amplitude detuning. Simulations and measurements have been performed to assess the efficiency of the emittance blow-up as a function of the chromaticities.
Paper: TUPG26
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG26
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPG27
Parallel beam-based alignment for the EBS storage ring
1278
The parallel beam based alignment technique developped at SLAC is applied for the EBS storage ring. The results are compared with the standard beam based alignment technique used for operation.
Paper: TUPG27
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG27
About: Received: 10 May 2024 — Revised: 16 May 2024 — Accepted: 16 May 2024 — Issue date: 01 Jul 2024
TUPG29
Present status and future project of Synchrotron Light Sources at KEK
1286
Two synchrotron radiation sources, the 2.5 GeV Photon Factory Storage Ring (PF ring) and the 6.5 GeV Photon Factory Advanced Ring (PF-AR), have been in stable operation at the High Energy Accelerator Research Organization (KEK) for over 40 years. This paper first describes the current operational status and recent developments at PF. Next, a new concept of hybrid light source (PF-HLS) combining the advantages of a superconducting linac and a low-emittance storage ring is described. In the preliminary design, the energy range is from 2.5 GeV to 5.0 GeV, and the storage ring will be constructed in a green field with a circumference of 750 m. The design baseline for superconducting linac uses the International Linear Collider (ILC) specifications.
Paper: TUPG29
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG29
About: Received: 15 May 2024 — Revised: 16 May 2024 — Accepted: 16 May 2024 — Issue date: 01 Jul 2024
TUPG35
ALS-U accumulator ring raft and dipole installation
1302
The ALS-U project is an upgrade to the Advanced Light Source (ALS) at the Lawrence Berkeley National Laboratory that aims to deliver diffraction-limited x-ray beams with an increased beam brightness of two orders of magnitude for soft x-rays compared to the current ALS facility. A nine-bend achromat lattice Storage Ring (SR) and a three-bend achromat Accumulator Ring (AR) will be installed in the facility in two phases. The AR is currently being installed in the ALS facility during its regularly planned shutdowns while the SR upgrade will follow during a 12 months shutdown. AR rafts and dipoles are being installed with ground based tooling and overhead crane lifting methods. This paper focuses on the AR installation. In particular we will describe the engineering design, prototyping and testing of the customized ground based installation tooling, which led to a successful installation of the first AR production rafts and dipoles in the ALS tunnel.
Paper: TUPG35
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG35
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
TUPG37
Status of the Advanced Light Source
1309
The LBNL Advanced Light Source, a pioneering third-generation soft x-ray synchrotron radiation source operating at 1.89 GeV with a 2~nm beam emittance, stands as one of the earliest facilities in its class, continually evolving to maintain its status at the forefront of soft x-ray sources. This paper reviews the most significant advancements in the accelerator's hardware and software infrastructures and presents the machine operational statistics over the last 15 years.
Paper: TUPG37
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG37
About: Received: 12 May 2024 — Revised: 19 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
TUPG54
Comparison of BBA methods for commissioning of fourth generation light sources
1369
Beam based alignment (BBA) plays an important role in the commissioning of the fourth generation light source but it takes a lot of time with several hundreds of BPMs. To speed up BBA, a method using AC excitation, called fast BBA, has been proposed and is tested in several 3rd generation light sources. We have recently also proposed and tested a new BBA based on the neural network machine learning. In this paper, we will compare these new BBAs with conventional BBA in term of error, speed and some other aspects such as the betatron coupling.
Paper: TUPG54
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG54
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPG56
Status of undulators for the APS upgrade
1376
The Advanced Photon Source Upgrade (APS-U) project has developed and installed a multi-bend achromat (MBA) lattice operating at 6.0 GeV beam energy to replace the existing APS storage ring lattice that operated at 7.0 GeV. A major part of the project is to install 60 hybrid permanent magnet undulator (HPMU) insertion devices (IDs) that include 12 revolver undulators, each with two magnetic structures (for a total of 72 magnetic structures); and one electromagnetic undulator for intermediate energy x-rays (IEX). These IDs will outfit 35 sectors. We have developed new HPMU designs for five different period lengths used in 46 magnetic structures, and we will reuse 26 existing magnetic structures with four additional period lengths. Eight new superconducting undulators (SCUs) have been designed and built with two short period lengths and three different overall lengths [1-3]. The SCUs will be installed in both inline and canted configurations after beam commissioning is completed and the user runs start. Demanding field requirements for the undulators were expected to be challenging for the undulator tuning, especially given the tight schedule. All undulators underwent rigorous tuning and control system tests before they were installed in the new storage ring. We will provide a status and schedule update including presenting measurement results of the IDs.
Paper: TUPG56
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG56
About: Received: 14 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
TUPR01
RF power station stabilization techniques and measurements at LNF-INFN
1417
In the framework of EuPRAXIA@SPARC_LAB project, we are studying possible solutions to upgrade and measure the amplitude and phase stability of the RF accelerating fields generated by a klystron. These studies concern the C- and X- band klystrons installed in the LNF infrastructures. In particular, we will present our work on a fast phase feedback around the C-band power station (50 MW klystron and solid state modulator) installed at SPARC_LAB. We are trying to push the timing jitter below the standard limit of such systems (few tens of fs RMS). A second topic is the study of the jitter of the X-band power station (50 MW klystron and solid state modulator) installed in the TEX facility. Precise measurements on amplitude and phase of this system will be reported at different positions both upstream (LLRF and pre-amp) and downstream (waveguides and prototype structure) the klystron.
Paper: TUPR01
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR01
About: Received: 09 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
TUPR04
Preserving restoring and conditioning the RF cavities of the storage ring for the Advanced Photon Source upgrade
1425
The Advanced Photons Source (APS) storage ring (SR) underwent an upgrade to the multi-bend achromat (MBA) lattice recently. As part of the upgrade, four out of the sixteen Radio Frequency (RF) cavities were removed from the storage ring. The remaining twelve cavities were left in place during the entire upgrade process and restored to full operating power to support beam commissioning once the installation activities were completed. This paper provides details on the planning and preparations made to preserve the cavity integrity during the installation period, challenges faced while restoring the cavities and how the cavity power coupler beta values were determined.
Paper: TUPR04
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR04
About: Received: 15 May 2024 — Revised: 24 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
TUPR07
Development of a spill-structure manipulation cavity and first experiment with beam in SIS18
1432
For several years, significant effort has been spent at GSI to improve the time structure of the spill during slow extraction in SIS18. This led to the requirement to extend the possibilities to experimentally improve the micro-spill structure by partially or fully capturing the beam with an RF of more than 40 MHz. Therefore, a so-called spill-structure manipulation cavity was designed, realized and optimized which allows the mentioned experiments. In this contribution, the design of the cavity and the challenges of its realization are described, and measurement results concerning the first experimental operation in the SIS18 synchrotron are presented.
Paper: TUPR07
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR07
About: Received: 14 May 2024 — Revised: 22 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPR19
Design of an X-band parallel-coupled accelerating structure for future linacs
1454
As compared to conventional travelling-wave (TW) structures, parallel-coupled accelerating structures eliminate the requirement for the coupling between cells, providing greater flexibility in optimizing the shape of cells. Each cell is independently fed by a periodic feeding network for this structure. In this case, it has a significantly short filling time which allows for ultrashort pulse length, thereby increasing the achievable gradient. In this paper, a design of an X-band parallel-coupled TW structure is presented in detail.
Paper: TUPR19
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR19
About: Received: 14 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPR22
New design techniques on matching couplers for travelling wave accelerating structures
1464
Numerical optimizations on couplers of the traveling wave accelerating structures usually require lots of calculation resources. This paper proposes a new technique for matching couplers to an accelerating structure in a more efficient way. It combines conventional Kroll method with improved Kyhl method, thereby simplifying the tuning and simulation process. We will present the detailed design of a constant-gradient C-band accelerating structure based on this new method.
Paper: TUPR22
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR22
About: Received: 14 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPR28
LANSCE 805 MHz klystron reliability analysis
1486
Los Alamos Neutron Science Center (LANSCE) relies on 44 klystron modulator systems to feed the accelerating cavities and produce proton beam of 800 MeV. This paper focuses on the new VA-862A1 86kV 1.25 MW klystron units and aims to compare their performance with previously purchased units. Service hours for each klystron unit was used as the primary metric in the analysis and records from various sources cross-corroborated to confirm recorded information. Factors such as prior repair/rebuilds, factory acceptance tests and runtime notes were carefully inspected to provide a comprehensive view of the klystron performance during analysis. Klystron units currently being used in the LINAC were surveyed along with failed units and analysis performed to predict the next failure. The frequency and cause of failure was also compared with historical performance and failure data and results utilized for LANSCE SCCL performance optimization.
Paper: TUPR28
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR28
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
TUPR43
Extended Jiles-Atherton hysteresis model to accurately predict fields in a Rapid Cycling Synchrotron dipole magnet
1510
Particle accelerators use high field quality magnets to steer and focus beams. Normal conducting magnets commonly use soft iron for the yoke, which is subject to hysteresis effects. It is common practice to use an initialization procedure to accomplish a defined state of the magnet for which its hysteresis behavior must be known. In this article, a variation of the scalar Jiles-Atherton model with an improved physical basis called the Extended Jiles-Atherton (EJA) model is employed to predict the B-H trajectories in a Rapid Cycling Synchrotron (RCS) magnet. Simulations are conducted using COMSOL Multiphysics using the external material feature to integrate EJA model with the Finite Element Method (FEM). Results from the experimental studies conducted on a magnet prototype are also presented. Finally, potential improvements in the model and extension to the case of a two-dimensional anisotropic material are discussed.
Paper: TUPR43
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR43
About: Received: 14 May 2024 — Revised: 18 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
TUPR54
Transient finite-element simulations of fast-ramping muon-collider magnets
1548
Conceptual studies for a muon collider identify fast-ramping magnets as a major design challenge. Rise rates of more than 1 T/ms are attainable with normal-conducting magnets, incorporating iron yokes to make sure that stored magnetic energies and inductances stay below reasonable thresholds. Moreover, for energy efficiency, the magnets need to exchange energy with capacitors, such that the electric grid only needs to compensate for the losses. The design of such magnet systems is based on two- and three-dimensional finite element models of the magnets coupled to circuit models of the power-electronics equipment. The occurring phenomena necessitate nonlinear and transient simulation schemes. This contribution presents the analysis of a two-dimensional, nonlinear and time transient analysis of a bending magnet, energized by a symmetrical current pulse of a few ms.The magnet yoke is represented by a homogenized material refraining from the spatial discretization of the individual laminates, but nevertheless representing the true eddy-current and hysteresis losses.
Paper: TUPR54
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR54
About: Received: 15 May 2024 — Revised: 17 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
TUPR59
The mechanical behavior of the EIC beam screen during a magnet quench
1568
As part of the Electron-Ion Collide (EIC) upgrade at Brookhaven National Laboratory (BNL), the development of new beam screens for the vacuum system is underway. The mechanical design of the beam screens received support from CERN, particularly in addressing the mechanical response during a magnet quench, i.e. a resistive transitions in the superconducting magnets. Maintaining an overall elastic behavior in this component is crucial for the efficient functioning of the collider. The mechanical behavior of the EIC beam screen during a quench was initially analyzed using analytical methods and subsequently validated through a Multiphysics FEM model developed for the High-Luminosity LHC (HL-LHC) beam screen. The FEM model underwent an initial verification against analytical formulations in its simpler 2D magnetic-based version. Following this, thermal and mechanical physics were fully coupled with the magnetic model in a 3D framework. Various features, including partial weld penetration, pumping holes, and guiding rings, were then taken into consideration. Additionally, the plastic behavior of the beam screen materials was considered too. The assessment included an analysis of the maximum deformation and stress experienced by the EIC beam screen during a magnet quench, resulting in an overall elastic response for the proposed design.
Paper: TUPR59
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR59
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPR62
Investigation of reduced baking time on dynamic pressure in a Taiwan photon source front end system
1575
The Taiwan photon source (TPS), a synchrotron accelerator at the National Synchrotron Radiation Research Center in Taiwan, is a third-generation accelerator operating at 3 GeV that was designed to create a high energy photon source. The TPS front-end (FE) systems are located between the storage ring and beamline, which was designed to protect the safety of users as well as control experimental requirements. As the FE vacuum pressure influences the storage ring and beamline vacuum pressures, the FE vacuum systems must maintain a low dynamic pressure. Therefore, at the beginning of FE system construction, each FE vacuum system is baked at 200°C for 24 hours. Next, when the FE systems need to be upgraded or maintained lead to vacuum interventions, it must also be baked for 24 hours to recover a low dynamic pressure. However, the 24 hour baking process requires manpower support on-site owing to facility safety in the TPS tunnel. The maintenance of the FE systems takes two duty days. Therefore, reducing baking time is necessary in the TPS facility. The beam cleaning efficiency after reduced baking time has been described in this paper.
Paper: TUPR62
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR62
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
TUPR64
Setup of Goubau Line system for impedance-measurement of vacuum components at the NSRRC
1578
A setup of in-house made Goubau (G-) Line system for measuring the broadband impedance of vacuum components has been developed at the NSRRC for improving the beam-stability of the Taiwan Photon Source (TPS). A thin copper wire of 0.287 mm in diameter with polyimide-coating ~0.02 mm in thickness connects two horn-shape aluminum launchers face-to-face at a distance ~1.2 m far in between via two impedance-matching copper tapers welded on both ends of the wire that transports the surface waves through the vacuum duct under test (DUT) allocated at the middle of wire. Measurement of time domain reflection (TDR) for the G-Line has verified the systematic performance of matching the impedance of 50 ohms. A vector network analyzer measures the transmission parameters of S21 of the DUT from the G-Line that the longitudinal impedance of DUT can be obtained. Various DUTs of vacuum components e.g. flanges without gasket were measured for inspecting the G-Line performance, besides, the special designed aluminum gaskets with rf-shielding property sealed flanges were also inspected that must feature with ultra-low impedance. The detail design and the test results of the G-Line will be described.
Paper: TUPR64
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR64
About: Received: 15 May 2024 — Revised: 16 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
TUPR77
Development of a flux-concentrator-based 2-Tesla solenoid as a round lens for ultrafast microscopy
1597
Ultrafast Microscopy using MeV beam has made significant progress in the past 5 years. However, in order to push to atomic level resolution, other than the requirements of beam source, there are also high demands in high strength focusing elements. In comparison of commercial 100s KeV level electron microscopes, an MeV imaging beamline requires Tesla level lenses, preferably round solenoid lens. Tesla class DC solenoids are prohibitively bulky and heavy, and superconducting solenoids are not cost effective. We have developed a novel miniature flux concentrator based solenoid lens system for MeV UED/UEM applications. It can reach 2-Tesla with 1e-5 level stability (depending on the pulsed current source). Here we will present detailed development process and experimental results.
Paper: TUPR77
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR77
About: Received: 06 May 2024 — Revised: 16 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
TUPS02
Impact of beam screen eddy currents on transition crossing in the EIC HSR
1626
The Electron Ion Collider (EIC) hadron storage ring (HSR) requires a beam screen made of 75 μm copper layer on top of a 1 mm thick 316LN stainless steel sheet. The eddy currents produced by the dynamic fields at the beam screens of the transition jump quadrupoles will increase the field response delay. The field response curve depends on the thickness and Residual Resistivity Ratio (RRR) value of the copper layer. Manufacturing variances of thickness and RRR in the beam screens of the gamma transition quadrupole will result in different field response delays. This paper summarizes the effects from the beam screens on transition crossing. From the varying delays, the beta-wave and eta-wave may exceed typical RHIC values. The effectiveness of the jump will be estimated using simulations of the existing RHIC lattice.
Paper: TUPS02
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS02
About: Received: 15 May 2024 — Revised: 19 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPS07
Schedule management for large scale projects: the example of HL-LHC at CERN
1641
The High Luminosity Large Hadron Collider (HL-LHC) project seeks to significantly enhance the performance of the LHC to deliver ten times more data to the LHC Experiments. The project relies on cutting-edge systems and technologies deployed in the new facilities constructed to the HL-LHC requisites and replacing large existing equipment and systems in the LHC tunnel. The project complexity lies in the production and installation of innovative systems with strong interdependencies. A methodological schedule management approach is essential to ensure timely equipment delivery, anticipate potential risks and implement mitigation actions. This paper describes the schedule management aspects of the HL-LHC project, providing a robust framework adaptable to any large-scale project. It encompasses the management of the baseline changes, the monitoring of milestones, the planning and coordination of the new facilities installation, and the integration of the HL-LHC installations within the regular LHC maintenance program. Emphasizing the significance of key performance indicators (KPIs), the paper highlights the critical role of metrics as indicators of schedule robustness.
Paper: TUPS07
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS07
About: Received: 14 May 2024 — Revised: 18 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
TUPS09
Magnetic field modelling and symplectic integration of magnetic fields on curved reference frames for improved synchrotron design: first steps
1649
Compact synchrotrons, such as those proposed for cancer therapy, use short and highly bent dipoles. Large curvature drives non-linear effects in both body and fringe fields, which may be critical to control to obtain the desired dynamic aperture. Similarly to current practice, for straight magnet, our long-term goal is to aim at finding a parametrization of the field map that requires few terms to capture the relevant long term dynamical effects. This parametrization will then be used to optimize the performance of the synchrotron by long-term tracking simulations and, at the same time, drive the development of the magnet design by providing measurable quantities that can be computed from field maps. This paper presents the first steps towards the goal of representing the field with a few key parameters.
Paper: TUPS09
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS09
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
TUPS13
SIS18 Operation with U²⁸⁺
1661
In SIS18 U²⁸⁺ is used to reach highest heavy ion beam intensities for FAIR-operation. The medium charge state avoids losses during stripping processes and shifts the space charge limit to higher number of particles. Nevertheless, these ions are subjected to ionization loss in collisions with residual gas particles. Via ion impact induced gas desorption a feedback between vacuum quality and beam emerges, yielding in a beam intensity limitation. The installation of a charge exchange collimator is one of the several upgrade measures which have been performed to shift this limit. They are equipped with a current measurement system to detect charge exchanged ions, which is routinely used during machine experiments. In this proceeding we present different beam based measurements showing dynamic vacuum effects. The non-linear dependence of the extraction intensity on the number of injected particles, ramp rate, and brake-time for vacuum relaxation will be shown. Stored heavy ion beams were used for charge exchange current measurements. They allow conclusions on the vacuum conditions and are presented as well.
Paper: TUPS13
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS13
About: Received: 08 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPS14
Tracking error analysis on the power supply currents of J-PARC main ring main magnets
1665
The bending, quadrupole, and sextupole power supplies in the J-PARC Main Ring (MR) have been upgraded ramping up the average beam power for fast extraction (FX) operation for the neutrino oscillation experiment and slow extraction (SX) operation for the experiments in the hadron facility. The repetition cycles have been shortened from 2.48 sec. to 1.36 sec. for the FX operation and will be soon shortened from 5.2 to 4.24 sec. for the SX operation. The current ripples in the power supply generate the electric current errors of the main magnets. A tracking error can also generate the electric current deviation for the main magnets. A rather large tracking error has been observed after the power supply upgrade. An equivalent circuit analysis for the output load has been conducted to examine the cause. The impact on the beam optics for the longitudinal and transverse beam motions will be discussed. A manipulation of the power supply to improve the tracking errors is tried in the equivalent circuit analysis.
Paper: TUPS14
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS14
About: Received: 16 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
TUPS29
Slow extraction of a dual-isotope beam from SIS18
1698
Recently, the heavy ion synchrotron SIS18 at GSI was for the first time operated with a dual-isotope beam, made up of 12C3+ and 4He+. Such a beam can be used to improve carbon radiotherapy by providing online information on dose deposition, where the helium ions serve as a probe beam traversing the patient while depositing a negligible dose. For this, the accelerator has to deliver a slowly extracted beam with a fixed fraction of helium over the spill. The difference in mass-to-charge ratio of 4He compared to 12C is small enough to permit simultaneous acceleration and to make the two isotopes practically indistinguishable for the accelerator instrumentation. Yet, it may cause a temporal shift between the two components in the spill owing to the sensitivity of slow extraction to tiny tune variations. We investigated different extraction methods, and examined the time-wise stability of the dual-isotope beam with a beam monitoring setup installed in the GSI biophysics experiment room. A constant helium fraction was obtained using transverse knock-out extraction with adjusted chromaticity.
Paper: TUPS29
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS29
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPS32
Intensity reach of the barrier-bucket multi-turn transfer for fixed-target proton beam from PS to SPS
1710
Fixed target beams are extracted in five turns from the Proton Synchrotron (PS) at CERN to fill almost half the circumference of the Super Proton Synchrotron (SPS) with each transfer. To avoid beam loss during the risetime of the extraction kickers a longitudinal gap is generated with an RF barrier-bucket scheme. However, the synchronization of the gap with the PS extraction and SPS injection kickers requires the RF system to operate without any beam feedback during the transverse splitting process at the flat-top. Low RF voltage is moreover required during the process to keep a small momentum spread. Both conditions are unfavorable for longitudinal stability and a campaign of beam measurements has been performed to explore potential intensity limitations. Up to 3.3e+13 protons have been accelerated and remained longitudinally stable at high energy. Longitudinal coupled-bunch instabilities occurring at the intermediate plateau below transition energy are moreover cured by a dipole-mode feedback system initially developed for LHC-type beams. The contribution summarizes the results of the beam tests, probing the limits of the fixed-target proton beam production.
Paper: TUPS32
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS32
About: Received: 01 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
TUPS37
Shower simulations for the CERN proton synchrotron internal dump and possible shielding options
1730
During the Long Shutdown 2, the two internal dumps were replaced and successfully integrated into the CERN Proton Synchrotron operation to withstand the intense and bright beams for the High-Luminosity LHC. They function as safety devices, designed to swiftly intersect the beam’s trajectory and effectively stop the beam over multiple turns. A significant challenge arises from their limited energy absorption capacity. Previous studies indicate that at the maximum PS beam energy of 26 GeV, only about 7% of the energy is absorbed by the dumps upon their insertion. This study, employing a combination of the FLUKA and SixTrack simulation code chain, evaluates the absorbed dose in downstream elements in view of the projected increase of beam intensities, according to the LHC injector upgrade parameters, and explores the feasibility and potential benefits of implementing shielding as a mitigation measure.
Paper: TUPS37
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS37
About: Received: 15 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
TUPS38
Energy deposition in the new SPS's scrapers
1734
The successful injection of proton beams into the Large Hadron Collider (LHC) depends on an efficient scraping mechanism in the Super Proton Synchrotron (SPS). The beams accelerated in the SPS contain a significant non-Gaussian tail population. If not removed, this transverse tail population can cause high losses in the transfer lines and in the LHC injection elements. Subsequently, the Beam Loss Monitor (BLM) system may trigger a beam dump reducing the machine availability. As beam intensities increase to meet the parameters set by the LHC Injector Upgrade (LIU), the efficiency of the scraping operation becomes increasingly crucial. To fully cope with higher beam intensities in the framework of the High-Luminosity LHC (HL-LHC) project, an upgrade of the scraper system, consisting of two movable graphite blades, is being developed and scheduled for installation in January 2025. This article presents the results of a comprehensive simulation study that employs the FLUKA code coupled with SixTrack to assess energy deposition in the scrapers.
Paper: TUPS38
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS38
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPS39
Benchmarking power deposition from fast losses of heavy-ion beams at the onset of LHC Run 3
1738
In 2023, the LHC started its Run 3 operation with 208Pb82+ beams at 6.8 ZTeV, with a substantially higher number of bunches compared to past runs. Several new hardware systems were used operationally for the first time with high-intensity beams, including bent crystal collimators in the betatron cleaning insertion. Crystal-assisted collimation reduces the leakage of secondary ion fragments to the downstream dispersion suppressors, therefore decreasing the risk of quenching superconducting magnets. Nevertheless, one of the limitations encountered during the 2023 run were events with fast beam losses impacting the collimation system, which triggered multiple premature beam aborts on Beam Loss Monitors (BLMs). In this contribution, we present energy deposition simulations for these events, performed with the FLUKA tool, aiming to quantify the quench margin for the fast loss regime (~30 ms). To assess the predictive ability of the model, benchmarks against 2023 measurements are presented. The studies provide an important input for fine-tuning BLM thresholds in future heavy-ion runs, therefore increasing the tolerance to beam losses and hence the LHC availability.
Paper: TUPS39
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS39
About: Received: 15 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
TUPS47
Measurements of hysteretic effects and eddy currents on a FeCo magnet for the design of a novel ion gantry
1766
Hadron therapy uses scanning magnets to precisely deliver therapeutic beams, minimizing the damage to healthy tissues and reducing side effects. A collaboration between CNAO, CERN, INFN and MedAustron is developing an innovative gantry design with superconducting magnets and a downstream scanning system. The project features two compact scanning dipoles, each with a central field of 1 T – about three times higher than current magnets used in clinical practice. The heightened magnetic field, together with the large rate of varying currents required for operation during treatments, prompts an investigation into non-linearities, necessitating a careful study of their impact on the performances of the system. This contribution provides insights into the dynamic behavior of a prototype scanning magnet with a FeCo yoke, with measurements of saturation, hysteretic effects, and eddy currents performed at Frascati National Laboratories, elucidating the feasibility of the proposed model. Additionally, in view of clinical implementation, the study explores methods of fast degaussing.
Paper: TUPS47
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS47
About: Received: 15 May 2024 — Revised: 17 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
TUPS54
Bayesian optimization for beam centroid correction at ISAC
1786
Beam tuning in a post-accelerator facility such as TRIUMF’s ISAC involves a considerable amount of overhead and often leads to tunes which diverge from the theoretical optimum for the system, introducing undesirable effects such as aberrations or chromatic couplings. Bayesian Optimization for Ion Steering (BOIS) has been developed and tested to perform centroid corrective steering, after the transverse optics have been set to theory, in a method which is fully online and easy to deploy. Naïve multi-objective adaptations, scaleBOIS and boundBOIS have been introduced to perform corrective transverse steering with minimal transverse fields . Tests in the low-energy electrostatic transport beamlines at ISAC I performed comparably to human operators. This work holds promise for enhancing the efficiency and reliability of beam delivery via autonomous tuning methods, supporting TRIUMF's scientific mission.
Paper: TUPS54
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS54
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPS56
Machine learning-based extraction of longitudinal beam parameters in the LHC
1794
Accurate knowledge of beam parameters is essential for optimizing the performance of particle accelerators like the Large Hadron Collider (LHC). An initial machine-learning (ML) model for the reconstruction of the longitudinal distribution has been extended to extract the main parameters of multiple bunches at LHC injection. The extended model utilizes an encoder-decoder architecture to analyze sets of longitudinal profile measurements. Its development was partially driven by the need of a real-time beam energy error estimate, which was not directly available in the past. The derived beam parameters moreover include injection phase error, bunch length and intensity in the LHC, as well as the RF voltages at extraction from the Super Proton Synchrotron (SPS) and at capture in the LHC. In this paper, we compare the results of the ML model with conventional measurements of bunch length and energy error, from the beam quality monitor (BQM) and the orbit acquisition system, respectively. These benchmarks demonstrate the potential of applying the ML model for operational exploitation in LHC.
Paper: TUPS56
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS56
About: Received: 10 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
TUPS57
Machine learning enabled model predictive control of the FRIB RFQ
1798
Efficient control of frequency detuning for the radio-frequency quadrupole (RFQ) at the Facility for Rare Isotope Beams (FRIB) is still challenging. The transport delay and the complicated heat transfer process in the cooling water control system convolute the control problem. In this work, a long-short term memory (LSTM)-based Koopman model is proposed to deal with this time-delayed control problem. By learning the time-delayed correlations hidden in the historical data, this model can predict the behavior of RFQ frequency detuning with given control actions. With this model, a model predictive control (MPC) strategy is developed to pursue better control performance.
Paper: TUPS57
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS57
About: Received: 13 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
TUPS59
Data-driven model predictive control for automated optimization of injection into the SIS18 synchrotron
1800
In accelerator labs like GSI/FAIR, automating complex systems is key for maximizing physics experiment time. This study explores the application of a data-driven model predictive control (MPC) to refine the multi-turn injection (MTI) process into the SIS18 synchrotron, departing from conventional numerical optimization methods. MPC is distinguished by its reduced number of optimization steps and superior ability to control performance criteria, effectively addressing issues like delayed outcomes and safety concerns, including septum protection. The study focuses on a highly sample-efficient MPC approach based on Gaussian processes, which lies at the intersection of model-based reinforcement learning and control theory. This approach merges the strengths of both fields, offering a unified and optimized solution and yielding a safe and fast state-based optimization approach beyond classical reinforcement learning and Bayesian optimization. Our study lays the groundwork for enabling safe online training for the SS18 MTI issue, showing great potential for applying data-driven control in similar scenarios.
Paper: TUPS59
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS59
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPS61
Preliminary results on the reinforcement learning-based control of the microbunching instability
1808
Reinforcement Learning (RL) has demonstrated its effectiveness in solving control problems in particle accelerators. A challenging application is the control of the microbunching instability (MBI) in synchrotron light sources. Here the interaction of an electron bunch with its emitted coherent synchrotron radiation leads to complex non-linear dynamics and pronounced fluctuations. Addressing the control of intricate dynamics necessitates meeting stringent microsecond-level real-time constraints. To achieve this, RL algorithms must be deployed on a high-performance electronics platform. The KINGFISHER system, utilizing the AMD-Xilinx Versal family of heterogeneous computing devices, has been specifically designed at KIT to tackle these demanding conditions. The system implements an experience accumulator architecture to perform online learning purely through interaction with the accelerator while still satisfying strong real-time constraints. The preliminary results of this innovative control paradigm at the Karlsruhe Research Accelerator (KARA) will be presented. Notably, this represents the first experimental attempt to control the MBI with RL using online training only.
Paper: TUPS61
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS61
About: Received: 14 May 2024 — Revised: 29 May 2024 — Accepted: 29 May 2024 — Issue date: 01 Jul 2024
TUPS62
The reinforcement learning for autonomous accelerators collaboration
1812
Reinforcement Learning (RL) is a unique learning paradigm that is particularly well-suited to tackle complex control tasks, can deal with delayed consequences, and can learn from experience without an explicit model of the dynamics of the problem. These properties make RL methods extremely promising for applications in particle accelerators, where the dynamically evolving conditions of both the particle beam and the accelerator systems must be constantly considered. While the time to work on RL is now particularly favorable thanks to the availability of high-level programming libraries and resources, its implementation in particle accelerators is not trivial and requires further consideration. In this context, the Reinforcement Learning for Autonomous Accelerators (RL4AA) international collaboration was established to consolidate existing knowledge, share experiences and ideas, and collaborate on accelerator-specific solutions that leverage recent advances in RL. Here we report on two collaboration workshops, RL4AA'23 and RL4AA'24, which took place in February 2023 at the Karlsruhe Institute of Technology and in February 2024 at the Paris-Lodron Universität Salzburg.
Paper: TUPS62
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS62
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPS63
Overview of machine learning based beam size control during user operation at the Advanced Light Source
1816
The Advanced Light Source (ALS) storage ring employs various feedback and feedforward systems to stabilize the circulating electron beam thus ensuring delivery of steady synchrotron radiation to the users. In particular, active correction is essential to compensate for the significant perturbations to the transverse beam size induced by user-controlled tuning of the insertion devices, which occurs continuously during normal operation. Past work at the ALS already offered a proof-of-principle demonstration that Machine Learning (ML) methods could be used successfully for this purpose. Recent work has led to the development of a more robust ML-algorithm capable of continuous retraining and its routine deployment into day-to-day machine operation. In this contribution we focus on technical aspects of gathering the training data and model analysis based on archived data from 2 years of user operation as well as on the model implementation including the interface of an EPICS Input/Output Controller (IOC) into a Phoebus Panel, enabling operator-level supervision of the Beam Size Control (BSC) tool during regular user operation.
Paper: TUPS63
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS63
About: Received: 17 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
TUPS64
Estimation and control of accelerator beams by latent space tuning of generative models
1820
In this work we explore the estimation and control of a particle accelerator simulation of the 800 MeV linac at Los Alamos National Lab. We use a convolution neural network model with a low dimensional latent space to predict the phase space projections of the beam and beam loss, which are mapped from accelerator settings. In deploying the model, we assume phase space predictions cannot be measured but beam loss can, and we apply a feedback using the error in beam loss prediction to tune the latent space. With beam loss and phase space predictions well correlated, we apply constrained optimization techniques, simultaneous with phase space prediction, to control the beam phase space while keeping beam loss from reaching unsafe levels.
Paper: TUPS64
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS64
About: Received: 15 May 2024 — Revised: 22 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPS65
Radiographic source prediction for linear induction accelerators using machine learning
1824
The penetrating radiography provided by the Dual Axis Radiographic Hydrodynamic Test (DARHT) facility is a key capability in executing a core mission of the Los Alamos National Laboratory (LANL). Historical data from the two DARHT Linear Induction Accelerators (LIAs), built as hdf5 data structures for over a decade of operations, are being used to train machine learning models to assist in beam tuning. Adaptive machine learning (AML) techniques that incorporate physics-based models are being designed to use noninvasive diagnostic measurements to address the challenge of predicting the radiographic spot size, which depends on the time variation in accelerator performance and the density evolution of the conversion target. Pinhole collimator images recorded by a gamma ray camera (GRC) provide a direct measurement of the radiograph imaging quality but are not always available. A framework is being developed to feed results of these invasive measurements back into the accelerator models to provide virtual diagnostic measurements when these measurements are not available.
Paper: TUPS65
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS65
About: Received: 14 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPS68
SRF cavity fault prediction using deep learning at Jefferson Lab
1831
In this study, we present a deep learning-based pipeline for predicting superconducting radio-frequency (SRF) cavity faults in the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab. We leverage pre-fault RF signals from C100-type cavities and employ deep learning to predict faults in advance of their onset. We train a binary classifier model to distinguish between stable and impending fault signals, where each cryomodule has a uniquely trained model. Test results show accuracies exceeding 99% in each of the six models for distinguishing between normal signals and pre-fault signals from a class of more slowly developing fault types, such as microphonics-induced faults. We describe results from a proof-of-principle demonstration on a realistic, imbalanced data set and report performance metrics. Encouraging results suggest that future SRF systems could leverage this framework and implement measures to mitigate the onset in more slowly developing fault types.
Paper: TUPS68
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS68
About: Received: 02 May 2024 — Revised: 18 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
TUPS70
The Data Platform: an independent system for management of heterogeneous, time-series data to enable data science applications
1839
The Data Platform is a fully independent system for management and retrieval of heterogeneous, time-series data required for machine learning and general data science applications deployed at large particle accelerator facilities. It is an independent subsystem within the larger Machine Learning Data Platform (MLDP) which provides full-stack support for such facilities and applications [1]. The Data Platform maintains the heterogeneous data archive along with all associated metadata and post-acquisition user annotations. It also facilitates all interactions between data scientists and the data archive, thus it directly supports all back-end data science use cases. Accelerator facilities include thousands of data sources sampled at high frequencies, so ingestion performance is a key requirement and the current challenge. We describe the operation, architecture, performance, and development status of the Data Platform.
Paper: TUPS70
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS70
About: Received: 15 May 2024 — Revised: 16 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
TUPS71
A data science and machine learning platform supporting large particle accelerator control and diagnostics applications
1843
Osprey DCS is developing the Machine Learning Data Platform (MLDP) supporting data science applications specific to large particle accelerator facilities and other large experimental physics facilities. It represents a “data-science ready” host platform providing integrated support for advanced data science applications used for diagnosis, modeling, control, and optimization of these facilities. There are three primary functions of the platform: 1) high-speed data acquisition, 2) archiving and management of time-correlated, heterogeneous data, and 3) comprehensive access and interaction with archived data. The objective is to provide full-stack support, from low-level hardware acquisition to broad data accessibility within a portable, standardized platform offering a data-centric interface for accelerator physicists and data scientists. Osprey DCS has developed a working prototype MLDP* and is now pursuing full-scale development. We present an overview of the MLDP including use cases, architecture, and deployment, along with the current development status. The MLDP is deployable at any facility, however, the low-level acquisition component is EPICS based.
Paper: TUPS71
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS71
About: Received: 01 May 2024 — Revised: 17 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
TUPS76
Machine learning for data analysis and control of an MeV ultrafast electron diffraction system and a photocathode laser and gun system: updates
1858
An MeV ultrafast electron diffraction (MUED) in-strument system is a unique characterization technique used to study ultrafast processes in a variety of mate-rials by a pump-probe method. Combining this tech-nology with rapid data science and artificial intelli-gence/machine learning (AI/ML) technologies in con-junction with high-performance computing can create a turnkey, automated instrument. AI-based system controls can also provide real-time electron beam optimization or provide virtual diagnostics of the beamline operational parameters. Deep learning can be applied to the MUED diffraction patterns to recover valuable information on subtle lattice variations Such a data-science-enabled MUED facility will open this technique to a wider user base with a wider variation of experience, providing an automated or semi-automated state-of-the-art instrument, with a beamline scientist orchestrating the overall data collection pro-cess. Updates on research and development efforts pri-marily in the realm of initial studies of network con-nection between the ALCF and the Accelerator Test Facility (ATF) at Brookhaven National Laboratory are presented.
Paper: TUPS76
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS76
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPS85
Recent progress in laser wire-based H⁻ beam diagnostics at the SNS linac
1873
Laser wire has been used for nonintrusive profile and emittance measurements of operational hydrogen ion (H-) beam at the SNS linac. In this talk, we will describe the following recent developments in the laser wire system. 1) An upgraded light source and laser transport line which enables novel measurement capabilities including longitudinal profile measurement and high-energy proton beam extraction over potentially an entire macropulse. 2) A dual-detector emittance measurement scheme that boosted the dynamic range by an order of magnitude. 3) Design and implementation laser-wire-based nonintrusive longitudinal phase space measurement system.
Paper: TUPS85
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS85
About: Received: 17 May 2024 — Revised: 20 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPS87
Time-resolved evaluation of the transient responses of crystal optics to instantaneous heat deposition for wavefront integrity
1876
Our focus centers on numerical investigation into the transient response of optics when subjected to instantaneous heat deposition. The heat load deposited onto crystal optics, coupled with the emission of strain waves, has the potential to induce crystal deformation and vibrations. These phenomena carry detrimental consequences for optic performance, particularly in terms of wavefront preservation—an essential criterion for coherent XFEL beams. Our research involves an evaluation of optical performance in terms of the Strehl ratio at delay time. Ultimately, we aim to provide recommendations for establishing upper bounds on pulse energy and repetition rates during XFEL operation. These guidelines will play a pivotal role in optimizing XFEL performance while safeguarding wavefront integrity, thus advancing the capabilities of coherent X-ray beams in scientific and technological applications.
Paper: TUPS87
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS87
About: Received: 18 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
WEAN1
First dual isotope beam production for simultaneous heavy ion radiotherapy and radiography
1893
In the context of research on simultaneous heavy ion radiotherapy and radiography, a mixed carbon/helium ion beam has been successfully established and investigated at GSI for the first time to serve fundamental experiments on this new mode of image guidance. A beam with an adjustable ratio of 12C3+/4He+ was provided by the 14.5 GHz Caprice ECR ion source for subsequent acceleration in the linear accelerator UNILAC and the synchrotron SIS18. Despite the mass difference between the 4He+ and 12C3+ ions, both could be slowly extracted simultaneously at 225 MeV/u using the transverse knock-out extraction scheme. The ion beam has been finally characterized in the biophysics cave in terms of beam composition (particularly inter- and intra-spill He fraction), depth-dose-profiles, beam size, position and other parameters, all related to combined ion beam treatment and online monitoring. Utilizing high-speed particle radiography techniques, a fast extracted mixed ion beam has also been characterized in the plasma physics cave under conditions favorable to FLASH therapy.
Paper: WEAN1
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEAN1
About: Received: 15 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
WEAN2
Particle accelerator spin-transparent storage rings for beyond state-of-the-art science
1897
We will describe spin-transparent storage rings that exhibit spin-coherence times of several hours and store a large number of particles and their use in novel applications. For example, these rings can be used to directly measure the electric dipole moment of the electron, relevant to CP violation and matter-antimatter asymmetry in the universe, and to search for dark energy and ultra-light dark matter*. These rings can also serve as a compelling platform for quantum computing. In this presentation, we will describe how spin-transparent rings can be used in conjunction with ion traps to enhance scalability and increase quantum coherence times of ion quantum computing.
Paper: WEAN2
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEAN2
About: Received: 13 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
WEYD1
Status and outlook on slow extraction operation at J-PARC main ring
1905
The Main Ring (MR) at J-PARC (Japan Proton Accelerator Research Complex) is a proton synchrotron that accelerates protons from 3 GeV to 30 GeV. One of the two MR's extraction modes is slow extraction using third-order resonance toward the Hadron Experimental Facility, where various particle and nuclear physics experiments are conducted. There are two major points in the slow extraction: beam loss reduction and flat spill structure of the extracted beam. In the beam operation of 2021, we achieved a beam power of 65 kW with a high extraction efficiency of 99.5% and a spill duty factor of 60%, but requirements for further improvements from physics experiments have never stopped. From 2021 to 2022, various devices in the MR were upgraded. The primary purpose of this upgrade was to increase the beam power by shortening the acceleration time and increasing the repetition rate. To achieve this goal, we rebuilt most parts of the main magnet power supplies. The new power supplies are also expected to be significantly improved in the current ripple. Thus the time structure of the slow extracted beam is also expected to be greatly improved. In addition, plans are underway for further reduction of the beam loss through the use of beam diffusers and bent silicon crystals and for improvement of the spill structure by feedback algorithms reconstruction. This talk presents the status of the MR and the prospects of the slow extraction after the MR upgrade.
Paper: WEYD1
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEYD1
About: Received: 20 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
WEBN3
Availability and luminosity in the Future Circular Electron-Positron Collider (FCC-ee)
1915
The Future Circular Electron-Positron Collider (FCC-ee) is CERN's leading proposal for the next generation of energy-frontier particle accelerators. To reach integrated luminosity goals, it aims to be operational for minimum 80 % of the scheduled 185 physics days each year. For comparison, the Large Hadron Collider (LHC) achieved 77 % in 2016-2018. There are additional challenges in the FCC-ee due to its size, complexity and ambitious technical objectives. Availability is therefore a significant risk to physics deliverables. This paper presents the framework used to analyse availability and luminosity in the FCC-ee. To showcase its capabilities, first, a top-level system deconstruction reveals several key relationships for the Radio Frequency (RF) system. Second, two proposed technologies are simulated to overcome constraints in the Z, W operation cycle. Of these, pre-polarised bunch injection (PPBI) shows tremendous advantage for shielding integrated luminosity from a challenging availability environment.
Paper: WEBN3
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEBN3
About: Received: 14 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
WECD1
FCC-ee large-scale project installation planning: challenges & proposals
1934
CERN is contemplating further advancements in the energy frontier through the Future Circular Collider (FCC) study, envisioning a 90.7 km underground accelerator with multiple energy stages over time. Following the European Strategy for Particle Physics recommendation in 2020, CERN initiated a feasibility study to scrutinize all aspects of the FCC project. A crucial component of this study involves developing a timeline from project approval to the beam operation of FCC-ee, the first collider with electron and positron. Since the last planning iteration in 2018, modifications in the machine layout and shaft configuration necessitated a re-evaluation of the planning. This paper focuses on the updated planning for FCC-ee, spanning from civil engineering completion to beam operation. It compiles pertinent elements, including the civil engineering release date, layout data, and human resources regulations and limitations. These elements were analyzed systematically to derive a sector sequence. Employing a bottom-up approach in conjunction with resource constraints, an overarching plan for the FCC-ee machine until the start of operations was formulated.
Paper: WECD1
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WECD1
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPC13
Status of the RUEDI UK national facility design
1979
RUEDI (Relativistic Ultrafast Electron Diffraction & Imaging) is a proposed facility which will deliver single-shot, time-resolved, imaging with MeV electrons, and ultrafast electron diffraction down to 10 fs timescales. RUEDI is being designed to enable the following science themes: dynamics of chemical change; materials in extreme conditions; quantum materials; energy generation, storage, and conversion; and in vivo biosciences. RUEDI is proposed to be built at STFC’s Daresbury Laboratory in the UK.
Paper: WEPC13
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPC13
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPC16
The FORTRESS Beamline at Tsinghua University
1990
High-brightness photoinjectors generate low emittance, ultrashort electron beams that are capable of tracking dynamical states of matter with atomic-scale spatio-temporal resolutions via ultrafast electron scattering, as well as providing precisely-shaped electron beams for advanced acceleration research and large-scale facilities such as free-electron laser and inverse Compton scattering. In this paper, we report on the status of the newly constructed FORTRESS (Facility Of Relativistic Time-Resolved Electron Source and Scattering) beamline at Tsinghua University, which will be dedicated for studies of advanced electron sources and photocathodes, new electron beam manipulation and characterization methods, and ultrafast electron scattering applications. The layout, beam dynamics simulation, initial beam measurement results, as well as main hardware components will be discussed in detail.
Paper: WEPC16
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPC16
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
WEPC20
Experimentally verified reduction of local reflection of traveling-wave accelerating structure by output coupler undercoupling
2003
Hefei Advanced Light Facility (HALF) injector comprises 40 S-band 3-meter traveling wave accelerating structures, capable of delivering electrons of full energy 2.2 GeV into the storage ring. To mitigate the emission degradation caused by dipole and quadrupole fields in the coupler cavity, the coupler design incorporates a racetrack and a short-circuit waveguide to eliminate this impact. This article presents an introduction to design of the traveling wave structure and the results of cold and high-power testing. We performed tuning and preliminary measurements on accelerating structure, resulting in meeting the single-cell phase deviation and accumulated phase deviation requirements of the project objectives while maintaining good measurement consistency.
Paper: WEPC20
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPC20
About: Received: 05 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
WEPC43
An upgrade for the CeC cathode deposition system: co-deposition of K₂CsSb and CsTe/GaAs for CeC use
2060
Properties such as high quantum efficiency (QE), low thermal emittance, and longevity are crucial features for the rapidly developing electron accelorators. Compared to the traditional sequential deposition, the co-evaporation method is reported to yield better surface roughness, film crystallinity, and high quantum efficiency for photocath-ode materials. Here we present the effort in upgrading the coherent electron cooling (CeC) photocathode deposition system to adapt the co-evaporation growth method, the development of the co-evaporation recipe, and the prepa-ration of K-Cs-Sb photocathode using the developed system. QE of about 6.3% at wavelength 532 nm was obtained for co-deposited K2CsSb photocathode, where stoichiometry was determined by the deposition rate of each element. The system upgrade also enables the prepa-ration of GaAs photocathodes activating with Cs-Te. In our study, both CsTe and CsTe/CsO activated GaAs are prepared using the “yo-yo” method. QE of about 3.6% and 5% at wavelength 532 nm are obtained respectively. Lifetime measurements are performed and results are reported.
Paper: WEPC43
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPC43
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPC54
Fabrication of semiconductor photocathodes at ACERT
2086
Photocathodes play key roles in supplying electron beams for diverse research facilities. Among them, semiconductor photocathodes stand out for their high quantum efficiency (QE). Typically, a high QE, long operation time, low thermal emittance and fast response time are desired for the accelerator community. However, the performance of semiconductor photocathodes is extremely sensitive to growth conditions. In this presentation, I will delve into recent advancements in semiconductor photocathodes fabrication at Applied Cathode Enhancement and Robustness Technologies (ACERT) of Los Alamos National Laboratory (LANL). These updates allow us to fine tune growth parameters and fabricate photocathodes with high QE and low emittance at high gradient to meet the requirements of photocathodes for Cathodes and Radiofrequency Interactions in Extremes (CARIE) project at LANL. Specifically, I will highlight our progress in developing a control system that enables to accurately control growth parameters. Furthermore, I will show our preliminary results focusing on the fabrication of CsSb and CsTe photocathodes using both sequential and co-deposition methods.
Paper: WEPC54
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPC54
About: Received: 15 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
WEPC61
Concepts for more flexible UED/UEM operation
2105
Ultrafast electron diffraction and microscopy (UED/UEM) has advanced beyond proof-of-concept stage into the realm of instrumentation. To date, most UED/UEMs have been constructed around high-gradient RF-driven electron guns designed as X-FEL beam sources. A UED/UEM system driven by a CW beam, either normal- or superconducting, offers several potential performance benefits over high-gradient pulsed beam sources. These include the ability to operate at much higher average repetition rates, and the ability to extend measurement times beyond O(1 μs). If a quarterwave-type beam source is used, there is an additional possibility to vary the time between probe pulses by other than an RF period. In this paper we present the basis for this claim, discuss implications for detectors, and consider also utilization of probe electron beams at different beam energies.
Paper: WEPC61
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPC61
About: Received: 08 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
WEPC62
Development of new method of NEA Activation with Cs-Sb-O
2109
Negative Electron Affinity (NEA) activated GaAs photocathodes are the only one capable of generating spin-polarized electron beam larger than 90%. However, the NEA layer currently made from mainstream cesium (Cs) and oxygen (O) is chemically unstable, the NEA-GaAs photocathode has a rapid QE degradation over time or electron beam. As a result, it requires an operating vacuum pressure of 1e-9 Pa and has a short lifetime. Recently, a new NEA layer using heterojunctions with semiconductor thin film of alkali metals and antimony or tellurium has been proposed. The latest research shows that the NEA activation method using Cs-Sb-O is made by co-evaporation of Cs, O2 and Sb. However, the co-evaporation method has high demands on equipment. Therefore, in this work, we attempted to fabricate a Cs-Sb-O NEA layer using a separation evaporation method. Specifically, we attempted four recipes and successfully fabricated the NEA layer by Cs-Sb-O. We also evaluated the dependence of QE on Sb thickness and found that it is easy to form a NEA layer with 0.2 nm of Sb.
Paper: WEPC62
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPC62
About: Received: 09 May 2024 — Revised: 23 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
WEPC79
The design of a 2.3-cell X-band photocathode RF electron gun
2151
Recent advancements in electron beam compression methods have enabled the production of ultrashort electron beams at the sub-femtosecond scale, significantly expanding their applications. However, the temporal resolution of these beams is primarily limited by the flight time jitter, especially during their generation in photocathode RF electron guns. In this paper, to mitigate the impact of microwave phase jitter on the flight time jitter inside the electron gun, we designed a 2.3-cell X-band electron gun, which enables the electron beams to acquire maximum output energy and minimum in-gun flight time at the same injection phase. Moreover, the tolerance of the cavity's machining errors is assessed and the RF input coupler of this cavity has been designed. Our simulation results indicate that this design provides a solid foundation for further improving the temporal resolution of the electron beam.
Paper: WEPC79
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPC79
About: Received: 13 May 2024 — Revised: 19 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPC81
Shanghai laser electron gamma source beamline in Shanghai synchrotron radiation facility
2159
Quasi-monochromatic gamma-ray beams are produced in the laser Compton slant-scattering at the Shanghai Laser Electron Gamma Source (SLEGS) of the Shanghai Synchrotron Radiation Facility(SSRF) [1,2]. The laser Compton slant-scattering was pioneered to produce X rays as early as in 1996 [3] and has more recently been used to produced gamma rays in the MeV region at UVSOR [4]. The slant-scattering makes the usage of energy-tunable gamma-ray beams compatible with that of the synchrotron radiation in synchrotron radiation facilities operated at a fixed electron beam energy worldwide. The SLEGS is designed to produce gamma rays in the energy range of 0.66 – 21.7 MeV with a flux of 1e+5 - 1e+7 photons/s [2]. We have conducted test runs of the slant-scattering in the commissioning of the beamline to confirm the designed energy tunability and flux [5]. After a more careful measurement and data processing of the γ ray energy spectra in 2023, the newest experiment results of the quality of gamma-ray beams in flux and bandwidth is obtained and will be present in this report. The gamma-ray flux is in a range of 1e+4 - 3e+5 cps in 60° - 120° and the energy-resolution is in the range of 6 - 18%.
Paper: WEPC81
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPC81
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPG01
Beam position monitoring system and beam commissioning at APS-U storage ring
2170
Advanced Photon Source Upgrade (APS-U) storage ring, currently in installation and testing, is set for beam commissioning in early 2024. In the APS-U storage ring, there are 560 Beam Position Monitor (BPM) pickups, each equipped with high resolution electronics. This paper presents outcomes from pre-beam testing and beam commissioning of the APS-U BPM system. We discuss tailored features for advanced beam measurements, testing methodologies, challenges, and successful integration into the storage ring. Our findings demonstrate the robustness of the BPM system, emphasizing its crucial role in achieving the first beam and optimizing the APS-U storage ring's performance.
Paper: WEPG01
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG01
About: Received: 15 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
WEPG03
The RF BPM pickup and feedthrough testing results in the lab and SR for APS-U
2176
The BPM feedthroughs were manufactured and tested at the vendor and the APS lab. All feedthroughs were sorted in groups of four according to their capacitance. Four feedthroughs with close capacitance were welded to the housing in an assembly. The assemblies were measured in the APS lab to confirm their electrical performance acceptable and their x/y offsets were calculated according to VNA data. After the BPM assemblies were installed in the SR, they were measured again to verify their connections. The x/y offsets including the cables were compared with the previous data and will be used as the reference in beam commissioning. The testing results at the vendor, APS lab and APS-U SR were analyzed.
Paper: WEPG03
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG03
About: Received: 15 May 2024 — Revised: 18 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
WEPG16
Magnetron diagnostics with a novel optical fibre-Cherenkov detector
2218
Development of an optical fiber-based beam loss monitor (OBLM) is in progress at the Cockcroft Institute (CI), UK. The novel sensor utilizes the Cherenkov radiation (CR) emitted in optical fibers by relativistic particle showers generated in beam loss or breakdown events. Breakdowns are a problem for high-power magnetrons, such as those in medical accelerator facilities, as damage to the magnetron cathode reduces the device efficiency and lifetime. These events can be detected by emitted CR channeled along the fibers to photomultiplier detectors, and a time-of-flight method can be used to calculate the breakdown location from the CR arrival time. This has previously been demonstrated with the OBLM system on RF cavities (at CLARA, Daresbury Laboratory, and CTF3, CERN); and allows for rapid and reliable breakdown detection which is important for damage mitigation. This contribution presents proof-of-concept measurements from OBLM studies into magnetrons at Teledyne e2v, Chelmsford. It also discusses design adjustments made to improve the detector sensitivity and how the performance can be enhanced using the sensor (or similar).
Paper: WEPG16
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG16
About: Received: 14 May 2024 — Revised: 20 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
WEPG27
Real-time processing of longitudinal Schottky signals in CERN’s antiproton chain
2252
A low-latency, real-time diagnostic system for the analysis of longitudinal Schottky signals in CERN’s antiproton chain has been developed. The system, installed in CERN’s Antiproton Decelerator (AD), processes the combined output of two low-noise, wideband AC beam transformers. It uses a GPU and the NVIDIA CUDA Toolkit, exploiting the directly sampled data and hardware features provided by the low-level radio-frequency (LLRF) VMEBus Switched Serial (VXS) system and its companion ObsBox server, to implement the FFT-based multi-harmonic spectral analysis needed to set up and monitor the stochastic and electron cooling processes. Longitudinal beam properties, such as mean momentum and momentum spread, are also derived to evaluate and log the machine performance. This paper describes the implementation of the system and its integration within the CERN control system, achieved using the Front-End Software Architecture (FESA) framework and a graphics co-processor directly installed in the Front-End computer (FEC), running a real-time operating system environment. Preliminary results of its usage in the Extra Low ENergy Antiproton (ELENA) ring and next steps to process bunched beam spectra are also presented.
Paper: WEPG27
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG27
About: Received: 02 May 2024 — Revised: 18 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
WEPG29
Impedance and thermal studies of the CERN SPS wire scanners and mitigation of wire heating
2260
All wires of the four CERN SPS rotational wirescanners broke when increasing the beam intensity towards the target for the LHC Injector Upgrade in 2023. Impedance and thermal studies were immediately launched, with simulations and measurements indicating that beam induced heating from resonant modes on the thin wire could be sufficient to cause these breakages. Mitigation measures to displace electromagnetic losses away from the wire were proposed and implemented. This allowed a much higher beam intensity to be reached, close to the LIU target. Simulations now predict that the modified wirescanners can sustain the LIU beam parameters.
Paper: WEPG29
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG29
About: Received: 13 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
WEPG34
Time-interleaved-sampling for high bandwidth BPM signals
2280
BPM signal processing uses digital or analog down-conversion to report phase and magnitude at a single frequency, however the digitized BPM signal may contain many more harmonics and a larger bandwidth of information which may be useful. An FPGA implementation is described which captures the full bandwidth BPM signal with minimal processing and resources. This approach can be scaled to captures as many beam harmonics as needed, limited only by the bandwidth of the ADC used. The periodic nature of the BPM signal is utilized to use time-interleaved sampling to effectively multiply the sampling rate of the ADC.
Paper: WEPG34
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG34
About: Received: 16 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
WEPG40
Wire scanner assessment of transverse beam size in the Fermilab side-coupled linac
2303
The Fermilab Side-Coupled Linac contains seven 805 MHz modules accelerating H- beam from 116 MeV to 400 MeV. Each module contains at least one wire scanner, yielding beam intensity at positions along a transverse direction. These wire scanners each contain three wires, mounted at different angles: "X", "Y", and 45° between "X" and "Y" to analyze coupling. Recently, a significant amount of transverse X-Y coupling was identified within wire scanner data from the Side-Coupled Linac, which has been present in data from the past decade. This realization has prompted an investigation into the wire scanner's utility as a diagnostic tool in the Fermilab Linac. This work presents efforts to better characterize the wire scanners' limitations and the phenomenon occurring in the Side-Coupled Linac.
Paper: WEPG40
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG40
About: Received: 15 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
WEPG41
Fermilab Booster beam emittances from quadrupole modes measured by BPMs
2307
The measurement of beam emittances by extracting the quadrupole mode signal from a 4 plate BPM was published at least 40 years ago. Unfortunately, in practice, this method suffers from poor signal to noise ratio and requires a lot of tuning to extract out the emittances. In this paper, an improved method where multiple BPMs are used together with better mathematical analysis is described. The BPM derived emittances are then compared with those measured by the Ion Profile Monitor (IPM). Surprisingly, the BPM measured emittances behave very well and are more realistic than those measured by the IPM.
Paper: WEPG41
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG41
About: Received: 13 May 2024 — Revised: 21 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPG51
Resonant spin depolarization at the test facility KARA: overview of recent efforts
2335
The Karlsruhe research accelerator KARA offers a setup to measure the beam energy with resonant spin depolarization. The depolarization is excited by the stripline kickers of the bunch-by-bunch feedback system and the resonant frequency is measured via change in Touschek lifetime. Energy measurements with resonant spin depolarization are implemented as a standard routine in the control system and are used regularly to measure both the beam energy and the momentum compaction factor for different energies and optics regimes. Long-time experience with the setup, short polarization time, and variation options of beam energy in combination with much available beam time qualify KARA as a test facility for systematic studies. Such studies are of particular interest for future colliders designed for precision studies like FCC-ee, as resonant spin depolarization is known for its high accuracy. This contribution presents the resonant spin depolarization setup at KARA and selected results of recent measurement campaigns.
Paper: WEPG51
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG51
About: Received: 15 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
WEPG55
Longitudinal phase space density tomography constrained by the Vlasov-Fokker-Planck equation
2350
Understanding the evolution of complex systems with numerous interacting particles requires advanced analytical tools capable of capturing the intricate dynamics of the phase space. This study introduces a novel approach to longitudinal phase space density tomography in an electron storage ring, leveraging constraints imposed by the Vlasov-Fokker-Planck equation. The Vlasov-Fokker-Planck equation provides a comprehensive description of the evolution of density functions in phase space, accounting for both deterministic and stochastic processes. Measurements of the turn-by-turn bunch profile offer a time-dependent projection of the phase space. Observing the bunch profile evolution of charged particles in regimes characterized by a rich phase space dynamics presents a challenging inverse problem for reconstructing the phase space densities. In this work, we present a tomographic framework for reconstructing the longitudinal phase space density of an electron bunch at the Karlsruhe Research Accelerator (KARA). This framework utilizes simulated data and applies the Vlasov-Fokker-Planck equation to drive the reconstruction process.
Paper: WEPG55
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG55
About: Received: 13 May 2024 — Revised: 18 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
WEPG59
Implementing bunch-by-bunch diagnostics at the KARA booster synchrotron
2361
In the upcoming compact STorage ring for Accelerator Research and Technology (cSTART), LPA-like electron bunches are only stored for about 100 ms, in which the equilibrium emittance will not be reached. Therefore, to measure parameters such as bunch profiles, arrival times and bunch current losses, bunch-resolved diagnostics are needed. The booster synchrotron of the KARA accelerator accepts pre-accelerated bunches from a racetrack microtron and accelerates them further over a 500 ms long energy ramp. As the KARA booster synchrotron has a similar circumference and injection energy as the cSTART storage ring, new bunch-by-bunch diagnostics developed there can be transferred to the cSTART project with minimal effort. Currently the diagnostic system of the booster is not designed for bunch-by-bunch diagnostics, thus after using the booster as a testbed for cSTART, such a system could be used permanently. At the booster synchrotron we use the picosecond sampling system KAPTURE-II to read-out a button beam position monitor and an avalanche photo diode at the synchrotron light port and compare the results with a commercial bunch-by-bunch system.
Paper: WEPG59
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG59
About: Received: 15 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
WEPG64
The study of single bunch instability at the Taiwan Photon Source
2371
Single-bunch instability is studied at the Taiwan Photon Source both with and without bunch-by-bunch feedback (BBF). The instability thresholds are investigated at various chromaticities by increasing the bunch current until the instability occurs. BBF and chromaticity can increase the maximum stored bunch current and allow the tune to cross the unstable region. As the bunch current increase, the tune around the betatron frequency decreases and the tune around the synchrotron sideband increases. High radiation doses are detected by beam loss monitors when the bunch current exceeds 2 mA, near the unstable region, originating from synchrotron light scattered by the photon absorber. As the single bunch becomes unstable, electron beam loss occurs after the first band magnet of the straight section with the smallest vertical aperture.
Paper: WEPG64
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG64
About: Received: 13 May 2024 — Revised: 16 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
WEPG65
MENT-Flow: maximum-entropy phase space tomography using normalizing flows
2375
Generative models can be trained to reproduce low-dimensional projections of high-dimensional phase space distributions. Normalizing flows are generative models that parameterize invertible transformations, allowing exact probability density evaluation and sampling. Consequently, flows are unbiased entropy estimators and could be used to solve the high-dimensional maximum-entropy tomography (MENT) problem. In this work, we evaluate a flow-based MENT solver (MENT-Flow) against exact maximum-entropy solutions and Minerbo's iterative MENT algorithm in two dimensions.
Paper: WEPG65
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG65
About: Received: 15 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
WEPG68
Sub-femtosecond resolution electro-optical arrival-time measurement of relativistic electron bunches in a free-electron laser
2386
SwissFEL is a normal conducting linear accelerator driving two separate free-electron laser (FEL) lines – one for soft and one for hard x-rays. We report jitter and correlation measurements of two electro-optical Bunch Arrival-Time Monitors (BAMs), which use directly the pulses from a mode-locked laser oscillator. The arrival-time is encoded in the amplitude of one single reference laser pulse in a fiber coupled Mach-Zehnder modulator driven by a fast RF-transient from a button pick-up. Using the modulation slope and the laser amplitude jitter, we demonstrate <1 femtosecond resolution at 200 pC bunch charges for the BAM with a 16 mm pick-up beam pipe diameter and <10 fs at 10 pC for the BAM with 8 mm pick-up beam pipe diameter. We also report a jitter correlation measurement of two independent BAMs over 1 min at 100 Hz machine repetition rate as well as a similar correlation measurement of one single BAM station with 8 mm pick-up beam pipe diameter and having two identical high resolution channels. The measured correlations are as low as 1.3 fs rms resulting in sub-femtosecond resolution of the optical detection scheme.
Paper: WEPG68
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG68
About: Received: 15 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
WEPG72
Fast laser focal position correction using deployed models
2393
Ultrafast high repetition-rate laser systems are essential to modern scientific and industrial applications. Variations in critical figures of merit, such as focal position, can significantly impact efficacy for applications involving laser plasma interactions, such as electron beam acceleration and radiation generation. We present a diagnostic and correction scheme for controlling and determining laser focal position by utilizing fast wavefront sensor measurements from multiple positions to train a focal position predictor. We present the deployment and testing of this scheme at the BELLA Center at Lawrence Berkeley National Laboratory. Online optical adjustments are made to a telescopic lens to provide the desired correction on millisecond timescales. A framework for generating a low-level hardware description of ML-based correction algorithms on FPGA hardware is coupled directly to the beamline using the AMD Xilinx Vitis AI toolchain in conjunction with deployment scripts.
Paper: WEPG72
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG72
About: Received: 16 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
WEPG82
Real-time measurements of the RF-path of an electro-optical bunch arrival-time monitor with integrated planar pickup structure with low-charge electron beams at ELBE
2407
Ultra-low-charge operation of free-electron lasers down to 1 pC or even lower, requires adequate diagnostics for both, the users and the operators. For the electro-optical bunch-arrival time monitor (BAM) a fundamental design update is necessary to yield single-digit fs precision with such low charges. In 2023 a vacuum sealed demonstrator for a novel pickup structure with integrated combination network on a printed circuit board (PCB) was built for operation at the free-electron laser ELBE at HZDR. Together with a new low-pi-voltage ultra-wideband traveling wave electro-optical modulator, this concept reaches an estimated theoretical jitter charge product of 9 fs pC. Proof-of-concept measurements with the pickup demonstrator were carried out at ELBE.
Paper: WEPG82
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG82
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
WEPG86
Gas jet dosimeter measurements at DCF for medical accelerator applications
2418
Achieving non-invasive in-vivo dosimetry is a critical objective in the field of ion beam therapy. The comprehensive real-time characterization of the ion beam is highly desirable to ensure the safety of patients, treatment precision, and the efficiency of the treatment facility. However, current methods have limitations in terms of the information they provide and can be invasive to the beam. This contribution focuses on the development of a non-invasive, gas jet-based in-vivo dosimeter for use in treatment facilities. This technique relies on a non-disruptive interaction of a low-density supersonic gas jet curtain with the primary treatment beam. An existing gas jet monitor-based ionization profile monitor was modified and coupled with the accelerator beamline at the Dalton Cumbrian Facility (DCF), UK (United Kingdom). The aim of the test was to conduct proof-of-concept measurements for the profile and dosimetry of beams having characteristics similar to the medical treatment facilities. Measurements were carried out for proton and carbon beams of varied sizes, energies, and currents. The results obtained from these measurements demonstrated the feasibility of such a dosimeter and are instrumental for its improvement. This contribution introduces the design of the adapted gas jet dosimeter, discusses the findings from the measurements, highlights the dosimetry challenges addressed and outlines the scope of improvement for an online non-invasive gas jet in-vivo dosimeter.
Paper: WEPG86
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG86
About: Received: 09 May 2024 — Revised: 17 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
WEPR12
First comparison studies in dynamic aperture for nested magnets and baseline lattice in the FCC-ee
2485
A significant project such as the FCC-ee (with 91.17 km circumference) entails numerous challenges to ensure the stability and performance of the machine. In the pursuit of contributing to the improvement of energy consumption during its operation, the exploration of Nested Magnets (NMs) as a means to reduce synchrotron radiation has been undertaken. This paper presents first studies on the Dynamic Aperture (DA) and the Momentum Acceptance (MA) of this novel design to guide the next developments.
Paper: WEPR12
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPR12
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
WEPR20
Probing FCC-ee energy calibration through resonant depolarization at KARA
2516
The FCC-ee collider physics program requires a precise determination of the center-of-mass energy. The average energies of the two colliding beams can be measured by resonant depolarization (RDP) of polarized electron and positron bunches. The depolarization is achieved by an electromagnetic device, e.g., a strip line, excited at a sweeping frequency. Once the excitation frequency is equal to the spin precession frequency, which is directly proportional to the beam energy, the polarization is lost or reduced. At KARA the resonant frequency is routinely measured via the change of the Touschek lifetime. We report on an RDP beam measurement campaign at the Karlsruhe Research Accelerator (KARA), exploring how this technique could be applied at the FCC-ee. In particular, we examine the sensitivity of the inferred value of beam energy to various parameters, such as the depolarize scan speed, the scan direction, and the beam operation energy.
Paper: WEPR20
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPR20
About: Received: 14 May 2024 — Revised: 18 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
WEPR38
Conceptual design of the HTS split coil test facility for the Muon Collider cooling section
2575
The cooling section of the Muon Collider requires a number of solenoidal coils of various diameters (0.05-2 m) and fields (2-60 T). An unusual feature of the cooling section is that the RF cavities operates under the large magnetic fields and field gradients generated by the focusing elements. Here we present the design of a test facility based on split coils, wound with HTS, to study the performance of RF cavities under magnetic field. The main characteristics are: 330 mm free room temperature bore, uniform 7 T field along 300 mm on axis, coils energized with parallel or antiparallel field: this last configuration provides a gradient field of about 40 T/m. The use of HTS in form of REBCO tape enables magnet operation at 20 K and cooling via solid conduction by cryocoolers. This facility will be a first prototype of the cooling cell magnets that are being designed in cryogen-free layout at 20 K for energy saving and will allow to anticipate system integration concepts. The conceptual design of the facility is almost frozen and the engineering design is well under way. If we get financial support by 2025 we can commission the facility in 2027.
Paper: WEPR38
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPR38
About: Received: 20 May 2024 — Revised: 24 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
WEPR44
Understanding of the new horizontal instability at the PS Booster after LIU
2594
Following the LHC Injectors Upgrade (LIU) project at CERN, the Proton Synchrotron Booster (PSB) has been upgraded to operate with a new injection kinetic energy of 160 MeV and an extraction energy of 2 GeV. To understand the performance of the accelerator in this new energy range, a series of measurements have been conducted, especially devoted to the beam stability to ensure the optimal operation of the machine. A horizontal instability, firstly observed in 2021 at about 1.6 GeV (between the old and the new extraction energy of the Proton Synchrotron Booster), has undergone in-depth investigation in measurements. Despite the identification of a mitigation strategy to cure the horizontal instability, efforts have also been focused to understand its source. The results have once again drawn the attention to the termination of the extraction kicker. As happened in 2018, a dedicated MD performed at the end of 2023 run with matched kicker termination confirmed the impact of the extraction kicker in this instability.
Paper: WEPR44
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPR44
About: Received: 10 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPR52
Bmad-Julia: a Julia environment for accelerator simulations including machine learning
2612
Bmad-Julia is a new, open-source software project for modern accelerator simulations with an emphasis on Machine Learning. As compared to existing accelerator codes, reverse differentiability, e.g. for the optimization of neural networks, will be embedded. Multiple standalone Julia packages are being developed that provide fundamental tools and methods commonly needed in accelerator simulations, it is envisaged that Bmad-Julia will be able to serve as the basis for developing new programs to meet the ever changing simulation requirements of high energy machines. By avoiding the necessity of "reinventing the wheel", programs that make use of Bmad-Julia packages can be developed in less time and with fewer bugs than programs developed from scratch. Included will be a package for accelerator lattice instantiation and bookkeeping, a package for handling physical and atomic constants, and a package for truncated Power Series Algebra (TPSA) with routines for manipulations and analysis including map inversion, partial map inversion, normal form decomposition, Poisson bracket, etc. Ultimately, all features of today’s versatile Bmad toolkit will be transferred, including polarized beams, radiation effects, beam scattering, symplectic tracking, and long-term dynamics. Discussed is the present state of the project as well as plans for the future.
Paper: WEPR52
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPR52
About: Received: 15 May 2024 — Revised: 16 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
WEPR55
Modelling intra-beam scattering in the LHC for longitudinal beam loss studies
2619
In the Large Hadron Collider (LHC), intra-beam scattering (IBS) is one of the main drivers of longitudinal emittance growth during the long injection plateau. With the halo of the longitudinal bunch distribution being close to the separatrix, IBS consequently drives beam losses by pushing particles outside the RF bucket at the flat-bottom. As IBS and beam losses impose a requirement on the minimum RF bucket size, this mechanism has an important impact on the RF power requirements for the High Luminosity (HL-) LHC. In this contribution, the effect of IBS is introduced in the Beam Longitudinal Dynamics (BLonD) tracking code. This numerical model is then benchmarked against analytical estimates, as well as against beam measurements performed in the LHC. The impact of IBS-driven losses on the RF power requirements is discussed through the correlation between the time spent at flat-bottom and the average bunch length, which translates into start-of-ramp losses.
Paper: WEPR55
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPR55
About: Received: 02 May 2024 — Revised: 19 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
WEPR58
Status of the time-dependent FEL code Genesis 1.3
2631
Version 4 of the widely used time-dependent FEL code Genesis 1.3 has been released. The C++ code keeps the entire bunch in memory and thus allows for self-consistent effects such as wakefields or long-range space charge fields. With sufficiently allocated distributed memory, Genesis 1.3 can represent each individual electron. This solves the problem of the shot noise statistics at any arbitrary frequency in the simplest way and allows for sorting and redistribution of particles among the computer cores for advanced FEL applications such as the Echo-Enabled Harmonic Generation schemes. This presentation reports on the new physics added to the code as well as features which simplify the setup of the simulations as well and the ability to link user-made libraries to adapt to the specific needs of each user.
Paper: WEPR58
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPR58
About: Received: 15 May 2024 — Revised: 22 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPR61
Measurements of the time-structure of the current to a single injection kicker module and simulation of its effect on the transverse beam dynamics in SIS100
2642
Distortions in the SIS100 injection kicker’s pulse time-form gives rise to beam emittance increase in the horizontal plane. Particle tracking simulations of the primary beam were carried out to try to predict the emittance at the end of the injection process for the modes of operation for antiproton (p̅) and Radioactive Ion Beam (RIB) production. The RIB cycle’s beam grew to just beyond the acceptance of the slow extraction separatrix at 27 Tm. During p̅ mode with the longitudinal RF cavities set to bunch the beam at the 5th harmonic of the beam revolution frequency instead of the originally planned 10th harmonic, the beam emittance increase was considerably reduced, resulting in -at most- negligible beam loss at the halo collimator.
Paper: WEPR61
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPR61
About: Received: 15 May 2024 — Revised: 18 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPR75
Simulation studies for the confinement of antiprotons for the AEgIS experiment
2684
The AEgIS (Antimatter Experiment on Gravity, Interferometry and Spectroscopy) project, based at CERN's Antiproton Decelerator (AD) facility, has undergone significant enhancements, capitalizing on the increased quantity of colder antiprotons made available by the new Extra Low Energy Antiproton Ring (ELENA) decelerator. These improvements aim to create a horizontal beam and enable a direct investigation into the impact of gravity on antihydrogen atoms. This exploration seeks to probe the Weak Equivalence Principle for antimatter. In AEgIS a series of circular ring electrodes and an axial magnetic field of 1T are utilized for the trapping of antiprotons. This contribution describes the design and optimization of the electrodes to generate a parabolic potential well to effectively trap the antiprotons. The behavior of the trapped antiprotons is reproduced by simulating a spherical source under different bias voltage settings applied to the electrodes. The general layout of the AEgIS trap is shown, alongside suitable electrode configurations, and results from electrostatic particle-in-cell code simulations carried out to optimize the confinement time of the antiprotons.
Paper: WEPR75
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPR75
About: Received: 09 May 2024 — Revised: 19 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
WEPS03
Hybrid plasma generator for high intensity fast pulsed ion sources
2694
The main challenge in the development of high intensity ion sources is, besides the space charge limited extraction, the available plasma density. Conventional plasma generators use e.g. arc discharge plasmas or RF generated plasmas. Preliminary tests are carried out on both types of plasma generators and plasma parameters are determined to create a basis for evaluation. A concept is being developed that combines the advantages of both types. This hybrid plasma generator will also be investigated in terms of plasma parameters in order to test a possible application for high intensity ion sources. Further the proposed plasma generator has the property that due to a permanently available low-density RF plasma a faster build-up of the highly dense arc discharge plasma may be achieved. The properties of the concept with regard to a fast plasma build-up time are being investigated in order to test a possible application for the fast pulsing of high intensity ion sources.
Paper: WEPS03
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS03
About: Received: 15 May 2024 — Revised: 19 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
WEPS04
A faster initial cesium transfer for the LANSCE H⁻ ion source
2698
The LANSCE H- Ion Source utilizes a cesium coated converter to induce H- surface conversion. To achieve an optimal cesium coating, a heated cesium reservoir and transfer tube vaporizes cesium onto the converter surface. An initial coating of cesium is done via an initial cesium transfer. During this process, the cesium heater is brought to a high initial temperature (250°C) and is slowly lowered to the operational temperature (~190°C) over six hours, followed by a static conditioning for another 18 hours to get the cesium converter coating optimal for H- surface conversion. Any reduction in the 24-hour cesium transfer process would allow more for experimental time for LANSCE experiments. Thus, there is high value in seeking to reduce the initial Cs transfer time. The LANSCE H- Ion Source Laser Diagnostic Stand was recently utilized to take cesium density measurements inside the H- Ion Source as a function of cesium reservoir temperature. A comparison of the measured cesium densities to the theoretical cesium vapor pressure values will be presented. Also, results using the measured cesium densities to calculate and run a faster cesium transfer process will be discussed.
Paper: WEPS04
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS04
About: Received: 15 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
WEPS17
Low RF loss DC conductive ceramic for RF windows
2733
Charging of RF windows has historically been problematic, frequently resulting in damage to the window severe enough that the window needs to be replaced. Many attempts have been made to prevent charging and therefore improve window lifetime, the most successful and common of which is coating the window with titanium nitride (TiN). Surface coatings such as TiN rely on the secondary electron yield of the coating material being lower than that of the ceramic window material, reducing the number of electrons emitted from a variety of mechanisms. An alternative approach is to introduce a small amount of DC conductivity to the ceramic itself, turning the traditionally insulating window into a mildly conductive one. This allows any charge on the surface of the window to drain rather than build until a discharge happens. A magnesium titanate ceramic has been developed with a small DC conductivity and used to make RF windows. Several window assemblies have been produced and tested, including 1.3 GHz waveguide and 650 MHz coaxial designs. The results of the conductive ceramic window test program will be presented.
Paper: WEPS17
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS17
About: Received: 16 May 2024 — Revised: 20 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPS37
REBCO sample testing at high power X-band
2772
SRF materials such as niobium have been extremely useful for accelerator technology but require low temperatures operation < 9 K. The development of high temperature superconductors (HTS) is promising due to their to their high critical temperature 89.5 K. This work intends to determine the high-power RF performance of such materials at X-band (11.424 GHz). Two kinds of REBCO coatings (thin film deposition and soldered tapes) on a copper substrate were tested. Testing was done in a hemispherical TE mode cavity due to its ability to maximize the magnetic field on the sample and minimize the electric field. We will report conductivity vs temperature at low and high power. We determine the quench field in the REBCO sample and explain the evidence which shows that the quenching is most likely due to reaching the critical current and not due to average applied heat load for powers up to 1.6 kW.
Paper: WEPS37
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS37
About: Received: 14 May 2024 — Revised: 19 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
WEPS38
Upgraded multiprobe sample inserts for thin film SRF cavity developments
2775
Optimisation of thin film (TF) coating parameters for producing SRF cavities requires rapid testing of superconducting properties. A dedicated multiprobe facility built at Daresbury Lab, based on a liquid He free cryocooler, allows such measurements to be performed. The facility has vacuum tubular inserts where the sample probe is loaded and cooled with He gas. The experimental inserts were either newly built or upgraded: (1) A DC resistance experiment allows measurements of critical temperature (Tc) and residual resistance ratio (RRR) on non-conductive substrates (e.g. sapphire). A newly designed insert allows better temperature control and easier sample change. (2) A new insert for magnetic field measurements of Tc on both conductive and non-conductive substrates. (3) An existing insert for planar magnetic field penetration experiments was significantly redesigned. It operates at lower temperatures (> 5.5 K), parallel magnetic fields < 600 mT, increased sensitivity, and enables measurements of field of first flux penetration (Bfp) and Tc on various substrates: copper and sapphire, the latter of which was impossible to measure with an older design.
Paper: WEPS38
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS38
About: Received: 15 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
WEPS40
T-Mapping diagnostic system for vertical test of SHINE superconducting cavity
2782
T-mapping diagnostic system is an indirect method to detect the internal surface of superconducting cavity during vertical testing. When superconducting cavity is powered, T-Mapping can detect the thermal instability and thermal collapse caused by defects. The goal of the project is to develop temperature detection devices that are highly accurate and easy to install. The development of the equipment plays a supporting role in the production of superconducting cavity, and can intuitive feedback the defects in the machining assembly, which is conducive to the improvement of the processing technology.
Paper: WEPS40
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS40
About: Received: 14 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
WEPS50
Progress on the autonomous event detection system for the laser particulate counter
2810
Field emission is one of the most important issues that limits the performance of the superconducting radio fre-quency (SRF) systems and leads to SRF cavity trips at the Continuous Electron Beam Accelerator Facility at Jeffer-son Lab. Studies have confirmed that particulates are the dominant source of field emitters and the particulates can be transported into a cavity from other parts of the accel-erator. To monitor the transportation of the particulates, a prototype of a novel, non-invasive laser particulate coun-ter (LPC) has been developed and tested. Experiments have been done to validate the capability of the LPC. We are developing autonomous event detection system to continuously monitor the readout from the LPC and to recognize real events generated by particulates from noises using machine learning model. In this report, we will present how the data are prepared and how the model is trained. We will also discuss the performance of the model.
Paper: WEPS50
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS50
About: Received: 13 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
WEPS61
Mapping the stray magnetic field at the Relativistic Heavy Ion Collider tunnel
2836
A new Rapid Cycling Synchrotron (RCS) [1] is designed to accelerate the electron bunches from 400 MeV up to 18 GeV for the Electron Ion Collider (EIC) [2] being built at Brookhaven National Laboratory (BNL). One of the two Relativistic Heavy Ion Collider (RHIC) rings will serve as the Hadron Storage Ring (HSR) of the EIC. Beam physics simulations for the RCS demonstrate that the electron beam is sensitive to the outside magnetic field in the tunnel. Significant magnetic fields are expected due to the HSR and the Electron Storage Ring (ESR) being at full energy during the RCS operation. The earth magnetic field at the location of the RCS center was measured throughout the circumference of 3870 m tunnel without RHIC operation. In addition, the fringe magnetic field from RHIC magnets at several locations during RHIC operation was measured and compared with simulation at different ramping currents. A robotic technology is being developed to automatically measure the stray magnetic field at any location during the RHIC (or future EIC) operation.
Paper: WEPS61
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS61
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
WEPS67
Status of coil-dominated discrete-cosine-theta quadrupole prototype for high rigidity isotope beams
2854
Iron-dominated superconducting magnets are one of the most popular and used design choices for superconducting magnetic quadrupoles for accelerator systems. While the iron yoke and pole tips are economic and effective in shaping the field, the large amount of iron also leads to certain drawbacks, namely, unwanted harmonics from the sextupole correctors nested inside of quadrupole iron pole tips. Additional problems include the nonlinear field profile present in the high-field regime caused by the presence of steel, the cryogenic design challenges of the iron yoke being part of the cold mass, and the mechanical challenges of mounting the sextupole and octupole, which will generate significant forces for apertures of the size being proposed. The Facility for Rare Isotope Beams is developing a coil dominated quadrupole as a future upgrade, and the presented work discusses the advantages of using an iron-free quadrupole, along with the methods and choices of the design and the current status of prototype fabrication. The methods and work presented will include the model results and the aspects of the model that have been verified up to the current status of prototype fabrication.
Paper: WEPS67
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS67
About: Received: 15 May 2024 — Revised: 22 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPS73
Time decay effect of the superconducting final focus quadrupole fields on SuperKEKB beam operation
2868
SuperKEKB is the particle collider of electrons at 7 GeV and positrons at 4 GeV, and it is the cutting-edge collider in the luminosity frontier using the “Nano-beam scheme”. The beam colliding operation of SuperKEKB started from 2018 May, and the peak luminosity reached at 4.678×1e-34 1/cm² 1/s with quite expert beam operation. In beam operation, the vertical tune of the positron beam was measured to decline exponentially with time just after exciting the final focus quadrupole magnets. To identify the source of the tune change, we performed the magnetic field measurements of the prototype final focus quadrupole magnets, and the exponential field change with time after exciting the magnets was measured and the measured field decay rates were found to be of equal size of the measured tune change during beam operation. Because the field change is due to the magnetization decay in the superconductor, NbTi, filament, we modified the excitation pattern of the magnets and canceled the field decay. We will report the measured beam tune changes, the prototype field measurement results and the condition of beam operation with the modified excitation patterns of the quadrupole magnets.
Paper: WEPS73
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS73
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
WEPS83
Passively stable pulsed optical timing distribution at 1030-nm wavelength using hollow core optical fibers
2903
New generation X-ray free electron lasers require reliable and precise synchronization of pulsed laser sources across various locations. This demands stable timing distribution to preserve ultra-low timing jitter, ultrashort pulse duration, and high peak power*. Fiber optic delivery, compared to free-space optics, offers advantages in flexibility, laser safety, ease of deployment and superior output beam quality. However, standard fibers with silica glass core face challenges like high dispersion, nonlinear pulse shaping and environmental sensitivity, causing excess timing jitter. Emerging anti-resonant hollow core fibers that guide light though a central hole have significantly lower environmental sensitivity, high nonlinearity threshold and low dispersion, while achieving attenuation similar to glass-core fibers**. This makes them an improved medium for low-noise transmission of fs pulses with high peak powers. Here, we experimentally demonstrate passively stable timing distribution of femtosecond pulses at 1030-nm center wavelength using sealed hollow core fibers with-out vacuum components. We have achieved a timing precision of 0.3 fs RMS from 1 Hz to 1 MHz and < 250 fs peak-to-peak for 12 hours with a hollow core fiber length of 72 m without requiring any transmission delay stabilization.
Paper: WEPS83
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS83
About: Received: 14 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
WEPS84
CERN accelerates sustainability
2906
CERN is pursuing several initiatives to reduce its impact on the environment through an integrated approach to address all the objectives set by the relevant United Nations (UN) Sustainable Development Goals (SDG). In particular CERN is committed to respect the net-zero paradigm for future machines and has established a Sustainable Accelerators Panel to harmonize the approach to sustainability of the various studies for future accelerators. In this paper we will describe the efforts taken in managing responsibly our technical installations and the process we are setting up to perform the lifecycle assessment of the different future projects to better understand the main drivers of CO2 emissions in order to minimize them by design.
Paper: WEPS84
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS84
About: Received: 15 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
THAD1
Beam storage monitor to achieve 3-D spiral injection in muon g-2/EDM experiment at J-PARC
2922
Anomalous magnetic moment (g-2) of a muon has been precisely measured by the BNL and FNAL experiments, and there is a discrepancy from the Standard Model prediction. A new measurement of muon g-2 is planned at J-PARC based on a different strategy. In the J-PARC experiment, a low emittance 300 MeV muon beam is injected into a compact storage orbit by newly developed 3-D spiral injection scheme*. Injected muons follow a vertical betatron oscillation around the storage orbit. A reduction of betatron oscillation amplitude is a key to achieve the physics goal of this experiment. This paper presents a new beam profile monitor which measures vertical distribution of stored muons to realize the 3-D spiral injection and to minimize vertical oscillation amplitude. There is a stringent requirement on the effective material budget in order to suppress multiple scattering of muon beam which passes through this monitor for hundred times on every cyclotron period. To achieve this, the monitor utilizes thin scintillating fibers of 0.2 mm diameter are placed with an interval of 10 mm. Reconstruction procedure of vertical beam motion from measured hit distribution will also be discussed.
Paper: THAD1
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THAD1
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
THAD3
Spatio-temporal measurements of stripper foil temperatures at 1.7 MW H⁻ beam power at the SNS
2925
We propose and demonstrate a time-resolved, two-dimensional temperature monitoring technique for nanocrystalline diamond stripper foils exposed to high-intensity hydrogen ion (H-) beams at the Spallation Neutron Source (SNS) accumulator ring which is independent of foil emissivity. The technique utilizes a two-color imaging pyrometer in the shortwave infrared (SWIR) spectral band to measure thermal radiation from stripper foils located 40 meters away from the measurement site. This work presents a unique optical design, optical calibration of the system using a high-temperature blackbody source, preliminary temperature measurement results from two stripper foils (new and used) under various H‒ production beam conditions with average powers up to 1.7 MW and energy of 1.0 GeV. This technique can be utilized to understand the thermal behavior of charge strippers under high-intensity particle beams, providing crucial feedback to operations to control foil temperature and ensure foil lifetime.
Paper: THAD3
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THAD3
About: Received: 15 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
THBN3
Lifetime of non-evaporable getter thin films over repeated activation
2960
Non-evaporable getter (NEG) coatings are used in accelerator beamlines to create an area of distributed pumping, allowing less external pumps to be installed, and smaller diameter tubes to be used. Both giving way to greater space for magnet arrays to better control the beam within, allowing more efficient accelerators to be produced. To work, NEG coatings must be activated by heating to a set temperature for 24 hours. This temperature depends on the properties of the NEG coating, and requirements of the system. The coating is then able to pump residual gasses out of the vacuum system, until it becomes saturated and will once again need activating. Over its a lifetime, a NEG coating will be activated and saturated numerous times, each time reducing the available sites for molecules to diffuse to during activation. Thus, eventually, the NEG coating will lose its capability, and will no longer be able to reach the same pumping capacity from the same activation regime. This study investigates the limits of NEG lifetimes, looking at the effect of multiple activations on the same coating. Samples of diameter 35 mm and length 50 cm were characterized by CO and H2 injections, from which the sticking probabilities and NEG coating capacity could be obtained. The samples were activated numerous times to see any degradation of the NEG coating. The results will be presented and discussed at IPAC 2024.
Paper: THBN3
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THBN3
About: Received: 15 May 2024 — Revised: 18 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
THPC09
Pulsed correctors for the beam vertical stability during injection in CESR
2982
Beam motion during injections could be a serious problem to x-ray users and jeopardize their experiments. In the Cornell Electron Storage Ring (CESR) the particles are injected with pulsed elements such as pulsed bumpers and septum which could cause transient motion of the stored beam. By analyzing the turn-by-turn position data of the stored beam acquired during injection, we identify the source of beam motion in different time scales. A new corrector coil is then designed to compensate the beam motion with 0.15 msec duration at a 60 Hz repetition rate in the vertical plane. In addition to the new corrector we also use one of the existing magnet coils to correct 60 Hz kicks and DC offsets. Although, during the last summer down the 60 Hz source was identified and suppressed by an order of magnitude, this corrector is still in use to minimize the injection transient. The waveforms, used to drive the correctors, are extracted based on the beam turn-by-turn coordinates and orbit kick analyses using the 110 CESR Beam Position Monitors data. In this paper we discuss the requirements and parameters of the new corrector, as well as the correction technique, which is proven to be effective.
Paper: THPC09
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPC09
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
THPC23
Machine-assisted discovery of integrable symplectic mappings
3027
Integrable systems possess a hidden symmetry associated with the existence of conserved quantities known as integrals of motion. These systems play an important role in understanding general dynamics in accelerators and have potential for future designs. This work will cover two automated methods for finding integrable symplectic maps of the plane. The first algorithm is based on the observation that the evolution of an integrable system in phase space is confined to a lower-dimensional submanifold of a specific type. The second algorithm relies on an analysis of dynamical variables. Both methods rediscover some of the famous McMillan-Suris integrable mappings and ultra-discrete Painlev\'e equations. Over 100 new integrable families are presented and analyzed, some of which are isolated in the space of parameters, while others are families with one parameter (or the ratio of parameters) being either continuous or discrete. In addition, the newly discovered maps are related to a general 2D symplectic map through the use of discrete perturbation theory. A method is proposed for constructing smooth near-integrable dynamical systems based on mappings with polygon invariants.
Paper: THPC23
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPC23
About: Received: 15 May 2024 — Revised: 19 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
THPC24
Optics corrections and performance improvements in the Bessy II Booster
3031
The BESSY II Booster has been reliably delivering beam to the storage ring for several decades. As part of an effort to better understand and control beam dynamics in the Booster, new instrumentation, including Libera Spark ERXR beam position processors, has recently been installed and commissioned. These instrumentation upgrades have enabled measurements and corrections of optics parameters throughout the acceleration ramp which were not previously possible, leading to understanding and mitigation of mechanisms for beam loss and instabilities. Here we describe the beam position measurement system, corrections to the tune and chromaticity, and the resulting improvements to the top-up operation of BESSY II.
Paper: THPC24
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPC24
About: Received: 13 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
THPC28
Design of the H- beamline for the LANL RFQ test stand
3043
The Los Alamos Neutron Science Center (LANSCE) accelerator produces high intensity H+ and H- beams for multiple experiments in fundamental and national security science. The proposed LANSCE Modernization Project (LAMP) is evaluating necessary upgrades to enable continuous LANSCE operations in years to come. LAMP seeks to upgrade the H+ and H- 750 kV Cockcroft-Walton (CW) generators with a dual-beam, 3-MeV Radiofrequency Quadrupole (RFQ). For technology maturation and know-how associated with this concept, an RFQ test stand with LAMP-like layout is being set-up to demonstrate dual-beam operation in an RFQ with all beam patterns required by experiments. The RFQ test stand will have 35-keV H+ and H- beamlines that simultaneously inject into a 750 keV RFQ. Assembly and initial characterization of the H+ beam is under way. The H- beamline has stringent requirements and will also demonstrate systems like a beam chopper and a low frequency buncher to produce required beam patterns. We describe the design of the H- beamline based on accelerator codes Warp and Impact.
Paper: THPC28
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPC28
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
THPC47
Beam based measurements of titanium coated ceramic chambers at NSLS-II
3101
We summarize recent experimental studies of the impedance and beam-induced heating of titanium-coated ceramic vacuum chambers used in the NSLS-II injection kickers. We installed a spare chamber (SN003) in test section C01, demonstrating that beam-induced power is effectively dissipated in the titanium coating. Equipped with 12 temperature detectors, we measured temperatures and beam currents during operational fill patterns. The results, highlighting the heating of chamber, will be thoroughly presented.
Paper: THPC47
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPC47
About: Received: 07 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
THPC55
Beam-cavity interaction in the CERN PS 80 MHz RF systems
3132
The 40 MHz and 80 MHz Radio Frequency (RF) systems in the CERN Proton Synchrotron (PS) are required to perform non-adiabatic bunch shortening before beam ejection. This manipulation allows to fit the bunches into the short RF buckets of the 200 MHz Super Proton Synchrotron (SPS). Although the impedance of the cavities is strongly reduced by feedback, the detailed understanding of the beam-cavity interaction is essential to evaluate their impact on the beam. This contribution focuses on the impedance characterization of the 80 MHz RF systems to describe how the RF amplification chain behaves as a function of beam current changes. Complementary measurement techniques, both beam and RF-based, were adopted. The results of the different measurements show good agreement. The aim is to study and predict possible beam quality degradation at beam intensities required by the High Luminosity LHC (HL-LHC), as well as to propose future consolidation to the high-frequency RF systems in the PS.
Paper: THPC55
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPC55
About: Received: 03 May 2024 — Revised: 22 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPC56
Simulation of beam loading compensation with RF-Track
3136
The beam loading effect results in a gradient reduction of the accelerating structures due to the excitation of the fundamental mode when the beam travels through the cavity. A recent implementation of this process in the tracking code RF-Track allows the simulation of realistic scenarios, thus revealing the impact of this phenomenon in start-to-end accelerator designs. In this paper, we present the latest update of the beam loading module which allows the simulation of the compensation of this effect and we explore the potential of the developed tool in heavy-loaded scenarios.
Paper: THPC56
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPC56
About: Received: 14 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
THPC62
Impedance computation for large accelerator structures using a domain decomposition method
3159
The beam coupling impedance is a key design parameter for all accelerator structures. Recently, we have introduced a novel simulation approach for impedance calculations in 3D-geometry. Unlike conventional methods, this approach is based on the solution of Maxwell’s equations in the frequency domain using a high-order finite element technique. The main challenge for all impedance simulations, however, is the huge amount of computational resources that is required for the numerical discretization of electromagnetically large accelerator structures. In this contribution, we introduce a specialized domain decomposition technique for impedance simulations. The technique allows to handle large accelerator structures by decomposing the computational domain into subdomains that interact by means of suitably chosen boundary conditions. We describe a class of such boundary conditions that accurately take into account the modal wave contributions traveling through domain interfaces in the presence of a particle beam. An application of the method considered in the paper is the full impedance characterization of a large in-vacuum undulator for the PETRA IV synchrotron source.
Paper: THPC62
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPC62
About: Received: 14 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPC63
Emittance growth studies due to Crab Cavity induced amplitude noise in the SPS
3163
In the context of the HL-LHC upgrade, RF Crab Cavities (CCs) are one of the key components. Due to the increased intensity, the collider will operate with a large crossing angle scheme and these CCs will be used to counteract the geometrical reduction factor coming from the crossing angle. Amplitude and phase noise injected from the Low-Level RF, are known to induce transverse bunch emittance growth. This contribution presents the latest measurements of emittance growth induced by amplitude noise. The measurement was performed thanks to the SPS Beam Synchrotron Radiation Telescope (BSRT), that has been used to characterize the evolution of the transverse distributions. The measured emittance growth was found to be dependent on the amplitude detuning induced by the SPS octupoles, although no dependence was predicted by the available theories and models. In this paper, the measurement results will be presented and discussed.
Paper: THPC63
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPC63
About: Received: 06 May 2024 — Revised: 18 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
THPC80
Bunch-by-bunch simulations of beam-beam driven particle losses in the LHC
3225
Recent experimental measurements in the Large Hadron Collider (LHC) have shown a clear correlation between beam-beam resonance driving terms and beam losses, with a characteristic bunch-by-bunch signature. This observation creates interesting conditions to study diffusive processes. Over the past few decades, early chaos indicators, frequency map analysis and dynamic aperture studies have been commonly used to study particle stability in circular machines. However, the underlying mechanisms driving particles to large amplitudes in the presence of high order resonances is still an open question. Leveraging on years of development on particle tracking tools, this paper presents full-fledged 6-dimensional bunch-by-bunch beam loss simulations in the LHC. The computed loss rates are shown to be in agreement with experimental observations from LHC Run 3.
Paper: THPC80
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPC80
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
THPC81
Study of the beam-beam interaction in an electron-positron collider with large Piwinski angle and crabbed waist
3229
To achieve very high luminosity, the next generation circular colliders adopt the crab waist collision scheme with a large Piwinski angle. In this scheme, beams collide with high current, low emittances, and small beta functions at the interaction point (IP). However, several effects arising from these extreme parameters, especially the coherent X-Z instability, will significantly impact the collider's performance, necessitating dynamic processing of longitudinal motion in a three-dimensional self-consistent treatment. The transverse vibration becomes coupled with the longitudinal motion, as well as the increase in horizontal beam size alters the interaction between beams and corresponding beam-induced effects. These instabilities limit the stable high luminosity area for the selected working point of the original design. Therefore, it is necessary to optimize the safe area of the working point by readjusting the parameters of the IP.In this paper, based on the Super Tau-Charm Facility (STCF) project in China, the instability caused by beam interactions is studied through numerical simulation. The relationship between the parameters at the IP and the stable selection area of the working point is systematically explored. The regularities found from simulations can assist future high luminosity electron-positron colliders in selecting the corresponding parameters. Additionally, some methods, such as adding adjustable devices to achieve stable high luminosity, are also proposed.
Paper: THPC81
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPC81
About: Received: 12 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
THPG01
A Kick-and-Cancel injection scheme for Diamond-II
3240
The Diamond-II storage ring upgrade will provide users with 1-2 orders of magnitude brightness increase over the existing Diamond facility, for which a quasi-transparent top-up injection scheme will be a key performance requirement [1]. The ring was originally designed to use a single-bunch aperture sharing injection scheme [2], in which short stripline kickers are used to kick the injected bunch into the storage ring's dynamic aperture but remaining weak enough to avoid kicking the stored bunch outside the acceptance. A modification to this scheme which implements a kick-and-cancel method [3] shows promise for the stored bunch. The kicker power supplies are thus required to provide a double-pulse with few-microsecond pulse spacing. This new method is expected to significantly improve the transparency and reduce the recovery time for the targeted bunch, along with minimizing transverse wakefield effects and any interactions with the transverse multibunch feedback.
Paper: THPG01
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG01
About: Received: 09 May 2024 — Revised: 18 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
THPG07
TPS booster power supply performance experiment and monitoring program
3261
The TPS is a latest generation high-brightness synchro-tron light source scheduled to be commissioned in 2014. Its booster is designed to ramp electron beams from 150 MeV to 3 GeV at a frequency of 3 Hz. There are 54 dipole magnets, powered by one power supply unit, and 84 quadrupole magnets, powered by 4 power supply units according to their respective functions. During routine user time, a top-up injection occurs every 4 minutes. At this time, the stability of the booster's power supply units greatly affects the smoothness of the injection process. This paper will discuss how variations in the booster power output waveform affect injection and the monitor-ing program developed for this purpose.
Paper: THPG07
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG07
About: Received: 09 May 2024 — Revised: 21 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPG15
Design and commissioning of a high-level control system for a medical isochronous cyclotron
3278
MEDICYC (MEDical CYClotron) is an isochronous cyclotron dedicated to radiotherapy which was built and commissioned in Nice, France, in 1990 by a local team aided by experts from CERN. The cyclotron accelerates H- to a maximum energy of 65 MeV and uses stripping to extract a proton beam. Its primary purpose is treating ocular melanoma by protontherapy but a significant research activity is also present on beam-lines dedicated for this purpose. An extensive refurbishment program of the cyclotron has been started to cope with the end-of-life and/or the obsolescence of several sub-systems. In this context, a new high-level cyclotron control system has been developed and implemented in 2021-2023. The primary responsibility of the system is the high-level coordination of the H- source, the RF system and the beam-line and cyclotron magnets to produce and deliver a beam with a given set of characteristics. A secondary responsibility is the collection, visualization and analysis of sub-system and beam data for monitoring and pre-emptive fault detection. In this contribution, the control system software architecture is presented and the infrastructure on which the systems are deployed is laid out.
Paper: THPG15
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG15
About: Received: 15 May 2024 — Revised: 19 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPG16
Investigation for the applicability of a Hall probe measurement in B-field control for synchrotron duty cycle optimization
3281
MedAustron is a state-of-the-art synchrotron-based accelerator complex that provides irradiation with proton and carbon ion beams. The implemented DCCT feedback based control of the current provides good results for magnets of the accelerator in terms of precision and accuracy. However, since the B-Field of the main ring dipoles is not directly controlled, parasitic, time consuming effects cannot be compensated. Hence, the implementation of a B-Field control system offers a major improvement opportunity for the operation. This contribution presents the measurement chain of the proposed solution which is centered around a Hall probe located in the so-called B-train magnet. This approach requires an assessment of the applicability of local Hall probe measurements for this purpose, including the development of a model for relating the respective local measurement to the integral field. Ultimately, the Hall probe has shown characteristics of high accuracy and a measurement uncertainty that is below the overall field error target of 2 units. The model was tested under laboratory conditions and an accurate estimation of the integral field has been observed in the scope of simulations.
Paper: THPG16
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG16
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
THPG19
ALS-U accelerator motion design and realization
3292
Transitioning from the aging ALS Geo MACRO motor controller, this paper details the meticulous selection process for a new, cost-effective standard to fulfill the diverse motion requirements of the upcoming ALS-U project. Targeting primarily simple stepper motors with varying current demands, the chosen solution seamlessly integrates into the existing ALS-U EPICS environment while preserving the established ALS motion architecture and EPICS IOC support. Notably, the solution maintains independence from Delta-Tau technology while comprehensively accommodating the project's required range of servo/stepper motor types and offering dedicated support for critical subsystems like Beam Scraper and Cold Finger motion. This document delves into the exhaustive selection process, from comprehensively summarizing the current architecture and ALS-U requirements to meticulously analyzing the results of a year-long evaluation of diverse vendor offerings.
Paper: THPG19
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG19
About: Received: 15 May 2024 — Revised: 19 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPG23
Novel clock and trigger solutions with ultra-high precision delay to support time-resolved experiments at TPS
3305
The TPS (Taiwan Photon Source) is a third generation 3 GeV synchrotron light source. Some beamlines use synchrotron pulses in conjunction with laser pulses for pump-probe experiments, which is a time-resolved experiment method for capturing the temporal evolution of the pumped process. Periodic X-ray pulses are provided by the synchrotron light source as detecting light (Probe), and laser pulses can be used as a pump to excite a target, which changes a certain property when excited. Pump-probe experiments re-quire a synchronized laser system to alter the delay time between X-ray pulses and laser pulses. It has been built a laser synchronizer and timing support system. One direct digital synthesizer (DDS) with fine delay adjustment can change the laser pump pulse relative to the X-ray pulse. The clock fanout buffer with output dividers provides the synchronized clocks required by the laser oscillator and laser source. An SBC (single-board computer) is employed as a control interface The software architecture is created using the EPICS framework, which is compatible with the TPS control system, and a GUI with the ability to adjust the time delay is created. The efforts will be described in this report.
Paper: THPG23
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG23
About: Received: 14 May 2024 — Revised: 16 May 2024 — Accepted: 16 May 2024 — Issue date: 01 Jul 2024
THPG24
Real-time data acquisition with CompactPCI serial platform at PSI
3308
Data acquisition (DAQ) is an ubiquitous feature in modern particle accelerator measurement and control systems. At the Paul Scherrer Institut (PSI), a next generation of electronic devices is being designed to meet the demands of upcoming renewal of facilities. The new developments utilize the CompactPCI Serial (CPCI-S.0) platform, and will cover a diverse set of applications, including Low Level Radio Frequency (LLRF), Longitudinal Beam Loss Monitoring (LBLM), and Filling Pattern Monitoring (FPM) systems. Careful design considerations and selection of an optimal architecture are crucial to fulfill a variety of DAQ requirements such as maximum frequency of acquisition, size of the data and different modes of triggering. In this contribution, we focus on the real-time DAQ implementations utilizing a multiprocessor system on chip (MPSoC) technology. We review the IP components developed in-house at PSI that provide the DAQ functionality. We demonstrate, that by reusing the IP components development, prototyping and testing of applications requiring the DAQ are accelerated.
Paper: THPG24
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG24
About: Received: 14 May 2024 — Revised: 18 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
THPG29
A multi-variable approach to mid-ranging control for unified operation of fast and slow correctors in fast orbit feedback system
3314
Advanced Photon Source Upgrade (APS-U) Fast Orbit Feedback (FOFB) system uses 160 fast and 160 slow corrector magnets to stabilize orbit measured at 560 Beam Position Monitors (BPM). We plan to operate both fast and slow correctors in a unified feedback algorithm at 22 kHz correction rate. Mid-ranging control is a proven approach for feedback systems with two manipulated inputs each exerting distinct dynamic effects to regulate a single output. This method resets the fast input to its chosen DC setpoint and proves beneficial when cost of fast input is more than the slower one. Unified operation of fast and slow correctors is a fitting application to mid-ranging concept which is well founded for two input one output systems. In this work, based on the cross-directional nature of the FOFB system we developed a multi-variable approach to mid-ranging control. It can be applied to FOFB with multiple fast and slow correctors, and multiple BPMs. Performance of proposed scheme is tested in simulations with APS-U FOFB prototype model in MATLAB. The feedback loop with fast and slow correctors is stable with mid-ranging algorithm, and the fast corrector drives effectively tracked setpoints.
Paper: THPG29
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG29
About: Received: 16 May 2024 — Revised: 21 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPG30
Improvement of the LHC orbit feedback testing framework
3318
During the Long Shutdown 2 (LS2 2019-2021) of the LHC, the orbit feedback correction software (OFB) of the LHC was redesigned to satisfy new requirements for LHC Run 3 (2022-2025) and to clean up legacy functionalities. The OFB is an essential component of LHC high intensity operation since the orbit must be stabilized to a fraction of the beam size during the entire LHC machine cycle. Redesigning such an essential and complex system during shutdowns requires thorough testing of the system functionality. The existing OFB testing system has been reviewed and improved based on the experience of LHC Run 2. An automatic, continuous integration tool has been put in place to validate future software developments before putting them in production. The solution for the OFB testing will be presented in this contribution.
Paper: THPG30
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG30
About: Received: 12 May 2024 — Revised: 20 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
THPG36
Continuous position estimation for the full remote alignment system of the High Luminosity LHC upgrade
3337
The Full Remote Alignment System (FRAS) is an alignment system remotely controlled and monitored that comprises almost one thousand permanent sensors distributed along the 200 meters of equipment that will be installed in the frame of the High Luminosity LHC (HL-LHC) project on either side of the ATLAS and CMS detectors. The sensors, along with their electronics and a system of motorized actuators, will be used to adjust the relative positions of the components remotely, in real time, with no human intervention needed in the irradiated environment of the tunnel. In this contribution we describe the design and the implementation of the position estimation algorithm which is a core-component of the FRAS. This algorithm will process the data provided by all the sensors to determine exact positions and orientations of the associated components in real-time. The position estimation module is designed as a reusable C++ library and builds on the existing CERN LGC, a modular least-square software. It will be fully integrated into the FRAS software stack and is entirely file-less during operation. In this paper we will demonstrate its performance in a realistic case study and showcase its ability to provide position updates on a much higher frequency than the required 1 Hz.
Paper: THPG36
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG36
About: Received: 15 May 2024 — Revised: 17 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
THPG38
Reducing background/noise in stretched wire alignment technique measurements
3345
The stretched-wire alignment technique is one method of magnet alignment for linear induction accelerators. The applications of the Stretched-Wire Alignment Technique (SWAT) have been implemented for aligning magnets/solenoids on the Scorpius linear induction accelerator which will be sited at the Nevada National Security Site and the Flash X-Ray (FXR) linear induction accelerator at Lawrence Livermore National Laboratory’s Contained Firing Facility. This article describes both systematic (repeatable) and random sources of background/noise as well as practical ways to either eliminate or mitigate them to acceptable levels. Systematic sources include reflections from wire ends, rapid sag due to ohmic heating of the wire, magnetic materials, and shot rate. Random sources include air currents, vibration of nearby equipment, mechanical stability of test equipment, and the instruments used to measure the wire motion. Mitigations include curve fitting and adaptive noise signal cancellation, and mechanical damping. Finite Element Analysis (FEA) was used to interpret results.
Paper: THPG38
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG38
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
THPG40
Time-of-flight beam loss monitor for the Advanced Photon Source Upgrade booster-to-storage-ring transport line
3348
We present initial results from the booster-to-storage-ring beam-loss monitor (BTSBLM) employing time-of-fight analysis to localize and minimize losses along the BTS line. The BTSBLM utilizes a pair of high-purity, fused silica fiber optic cables running in parallel along the 65-m BTS transport line. Photomultipliers located at both upstream and downsteam ends of each fiber monitor Cherenkov radiation generated by lost electrons. The downstream detectors receive temporally-compressed, higher-intensity, spatially-inverted signals, while the upstream waveforms are temporally expanded with lower intensity allowing finer time resolution; both upstream and downstream effects owing to the refractive index in the fiber glass. Each radiation-hard optical fiber is composed of 600, 660, and 710-micron-diameter core, cladding, and buffer and is similar to those used in the newly commissioned LCLS-II superconducting linac BLM system. Realtime waveforms are recorded on a fast oscilloscope and available for diagnostic observation through EPICS waveform records. Remote controlled high-voltage power supplies provide gain adjustment. Data from booster and storage-ring commissioning are presented.
Paper: THPG40
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG40
About: Received: 16 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
THPG45
The onine radiation monitoring system for Hefei Advanced Light Facility
3366
An advanced online monitoring system with dual systems is being developing for Hefei Advanced Light Facility (HALF). One is based on the C language, which integrates data acquisition, storage and interface display. The other is based on EPICS system, which developed Input/Output Controller (IOC) and Operator Interface (OPI) for data acquisition and display. The two systems are based on Ethernet TCP / IP protocol for data communication, but they are independent. The on-line radiation monitoring system of Hefei Advanced Light Source (ORMSH) have the function of neutron and gamma dose monitoring and alarming. The ORMSH contains 160 monitors for workplace monitoring and environmental monitoring. Each monitor combines data collection, storage, automatic upload. two alarm methods will be adopted for dose interlocking in ORMSH: instantaneous dose rate alarming and cumulative dose alarming. This paper describes in detail the implementation of the system infrastructure and functions.
Paper: THPG45
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG45
About: Received: 15 May 2024 — Revised: 19 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPG56
The high-level software of the beam position limits detector system for the Advanced Photon Source upgrade storage ring
3390
A new Machine Protection System (MPS) and the Beam Position Limits Detector (BPLD) system are being developed for APS Upgrade (APS-U) accelerator storage ring. The MPS/BPLD system consists of one main MPS and 20 local MPS/BPLD controllers distributed around the ring, each local controller is located on every odd double sector. Each LMPS handles one double sector. Each double sector can be equipped up to seven Libera BPM electronics units. Each Libera unit processes up to four BPMs at Turn-by-Turn (TbT) rate. The Beam Position Limits Detector (BPLD) provides two types of protections: BPLD-ID and BPLD-BM for insertion device (ID) front-end (FE) and bending magnet (BM) incident radiation protection respectively. We select bumps using orbit feedback in a machine simulation to test the position limits of the system consistent with accelerator physics requirements for stable beam. This paper introduces the high level software implementation of APS-U BPLD-ID and BPLD-BM validation.
Paper: THPG56
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG56
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPG60
Development of a second-generation system for the reliable distribution of machine protection parameters
3401
The Safe Machine Parameter (SMP) system is an electronic hardware-based system which has been an integral part of the LHC’s machine protection strategy since it started operation. Its primary objective is to provide several parameters and interlock signals to critical machine protection users across the LHC and SPS accelerators, whilst prioritizing high reliability and availability. After almost two decades of operation, there is a need to upgrade the SMP hardware electronics. In the High Luminosity LHC era the requirements of connected systems have changed, leading to new system functions and operational requirements which must be integrated into the new design. This paper details the electronic design considerations of developing the second-generation SMP. The general distribution of parameters relies on the CERN WhiteRabbit timing network renovation, for which dedicated high-precision clock components were selected and tested on a prototype board. Details of the hardware design and validation are discussed, along with the comprehensive upgrades aimed at delivering an SMP system with expanded monitoring and diagnostic features.
Paper: THPG60
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG60
About: Received: 14 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPG61
An approachable beam loss monitor configuration and operation tool for FRIB
3405
The folded Linear Accelerator (linac) at the Facility for Rare Isotope Beams (FRIB) presents many challenges to effectively utilizing beam loss monitors (BLMs) for machine protection. Dozens of ion chambers and neutron detectors are installed at various locations in the linac tunnel to monitor radiation from beam losses. Each device must be configured with thresholds to meet machine protection requirements for an array of beam destinations, ion species, beam energies, beam power, and response times. This presents an extremely large configuration space with numerous use-cases and beam modes to account for. We present a largely automated tool to effectively manage BLM thresholds that requires minimal input from operators.
Paper: THPG61
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG61
About: Received: 15 May 2024 — Revised: 18 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
THPG62
FRIB target thermal image processing for accurate temperature mapping
3409
The FRIB carbon disc target receives the primary beam at high power and produces rare isotope fragments. To avoid damaging the carbon disc target, it is rotated at 500 RPM and cooled. If these thermal management mechanisms fail, local temperatures on the target can increase to the point of material sublimation and structural failure. A thermal imaging camera was temperature calibrated and installed for the purpose of monitoring the target temperature map in real time. Various image processing strategies were deployed to improve the accuracy and usefulness of the resulting image. Processing stages include conversion from intensity to temperature, median filtering to remove dead pixels, and flat field correction to compensate for vignetting and edge effects.
Paper: THPG62
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG62
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
THPG63
FPGA design of FRIB chopper monitor system
3413
In FRIB we use chopper in the low energy beam line for beam power controls. As appropriate functioning of chopper is critical for both beam operation and machine protection, an FPGA-based chopper monitoring system was developed to monitor its operation for fixed duty cycle operation and has been in use to support operation. The chopper monitor shuts off beam promptly at detection of a deviation of duty cycle outside tolerance. For future higher beam power operation, automatic beam power ramp modes will be required where beam duty factor is dynamically ramped up following a predetermined sequence. Recently FPGA prototype is developed to enhance the chopper monitor to accommodate one of such dynamic modes, cold start beam mode. It is a design challenge to integrate all the beam modes in one FPGA while synchronizing with external timing system pulse generator and recording the process data and failure information. Detailed FPGA design for this enhancement of chopper monitor will be discussed in this paper, followed by the test result of integrated system of chopper monitor, global timing system pulse generator, high voltage switch of chopper control and EPICS control software.
Paper: THPG63
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG63
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPG64
Integration of LHC-type beam loss monitors into the machine protection system for the SIS100 synchrotron at FAIR
3417
The SIS100 heavy ion synchrotron is the central machine of the FAIR (Facility for Antiprotons and Ions Research) project at GSI. It presents complex challenges due to its features handling high-intensity ion beams from protons up to uranium. It demands sensitive beam diagnostics with robust Machine Protection Systems (MPS). Due to anticipated extreme conditions, one safety subsystem includes LHC-type Beam-Loss Monitors (BLMs). These BLMs play a critical role in beam diagnostics and machine safety, strengthening protection measures by enhancing monitoring capabilities for severe beam losses and triggering safe beam dump requests. These BLMs are gas chamber detectors which aim to prevent beam-induced quenching superconducting magnets and protect other machine components from damage. This document outlines a conceptual study of a Machine Protection System, integrating 168 LHC-type BLMs to safeguard the SIS100 synchrotron. The integration involves upgrading the readout electronic chain and adopting FPGA-based logic firmware to handle intricate rate counting requirements over specified time windows. Additionally, hardware sanity checks are carried out to prevent non-conformities and ensure reliability alongside beam loss rate counting. Overall, the focus on beam loss monitoring for the SIS100 within the FAIR project underscores the necessity for sophisticated diagnostic tools and protective measures to ensure the safe and efficient operation of this state-of-the-art synchrotron.
Paper: THPG64
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG64
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
THPG66
Machine protection system for TEX facility
3424
In the context of LATINO (Laboratory in Advanced Technologies for INnOvation) and Rome Technopole Projects founded by Regione Lazio and NextGenerationEu, and directly involved in the EuPRAXIA@SPARC_Lab flagship project, a testing facility for X-band (TEX) has been established at the Frascati National Laboratories of INFN. TEX is dedicated to the examination of radiofrequency X/C-band, aiming to develop and test the technologies and systems of a particle accelerator operating under such conditions. Given the complex nature of such a system and the advancement of technology to the forefront of the state of the art, it is imperative to have an advanced Machine Protection System (MPS) characterized by high reliability, availability, and safety, in accordance with IEC-61508 standards. Currently in development is a prototype MPS designed to autonomously initiate procedures to control operations and avert anomalies. An EPICS supervisor oversees the management of all devices and monitoring connected subsystems. Additionally, a real-time interlock system, based on distributed FPGA, is employed to swiftly respond to vacuum and RF systems during the next RF pulse.
Paper: THPG66
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG66
About: Received: 15 May 2024 — Revised: 22 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPG67
Modernization of DARHT axis-I debris blocker
3428
The Dual-Axis Radiographic Hydrodynamic Test Facility (DARHT) uses a spinning wheel debris blocker as a crucial machine protection system to prevent target debris from the electron to X-ray conversion process from traveling upstream and damaging the accelerator. The spinning wheel in use on DARHT Axis-I consists of two spinning disks normal to the beamline, each with an open slit that crosses the beamline at frequencies of 50 Hz and 40 Hz, creating an opening at a beat frequency of 8 Hz allowing the electron beam to pass through and shut behind it. In this poster, we present steps taken to improve the reliability and performance of the spinning wheel, which include replacing legacy and custom diagnostic components with off-the-shelf hardware. We also present the challenges and solutions in testing and deploying these upgrades without disrupting operation of the accelerator.
Paper: THPG67
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG67
About: Received: 15 May 2024 — Revised: 10 Jun 2024 — Accepted: 10 Jun 2024 — Issue date: 01 Jul 2024
THPG76
Improved beam loss accounting with fast data acquisition (DAQ) chassis
3446
Identifying the source of beam loss events in the CEBAF accelerator can be a challenging task. Determining whether an RF cavity with an unannounced gradient or phase transient is the culprit would be a valuable tool for operations staff in addressing recurring beam loss incidents. A prototype offline system was developed in the fall of 2022, utilizing a dispersive beam position monitor (BPM) and the existing switched electrode electronics BPM hardware. A commercial off-the-shelf data acquisition (DAQ) system was employed to capture BPM wire signals at a sample rate of 20 kS/s. The system was triggered by the fast shutdown signal, which disables the beam at the injector. Analysis of beam position and energy variation before a beam loss event was used to determine if the beam loss event was associated with an energy transient. The prototype system, implemented using National Instruments hardware and LabVIEW software, relied on a software trigger. Manual post-processing was required to ascertain whether the fault was due to an un-tripped cavity with a gradient or phase transient. This work presents a production-quality system that utilizes the same data acquisition hardware developed and installed in CEBAF to monitor the time domain RF control signals in the legacy analog RF systems. As the new system employs a hardware trigger, developing tools to automatically identify faults linked to energy transients unrelated to cavity faults will be straightforward.
Paper: THPG76
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG76
About: Received: 14 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
THPG81
HPSim simulation of the highly bunched WNR beam at LANSCE
3457
The linac at the Los Alamos Neutron Science Center (LANSCE) provides beam to five user facilities with various beam energy and timing patterns. While the other four facilities have the same 201.25-MHz micro-bunch structure created by a pre-buncher and main-buncher pair, the Weapon Neutron Research (WNR) requires significantly higher charge per micro-bunch. This is achieved via adding a low frequency buncher at 16.77 MHz to the Low Energy Beam Transport. Such highly bunched micro-bunches create several challenges in operation and remain a critical capability to maintain for the LANSCE Modernization Project. We will demonstrate the HPSim simulation of the WNR beam through the LANSCE linac as a tool to address these issues in the future.
Paper: THPG81
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG81
About: Received: 14 May 2024 — Revised: 20 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
THPG84
3D visualization and analysis of neutron scattering data in the control room
3465
Neutron scattering experiments have undergone significant technological development through large area detectors with concurrent enhancements in neutron transport and electronic functionality. Data collected for neutron events include detector pixel location in 3D, time and associated metadata, such as sample orientation and environmental conditions. Working with single-crystal diffraction data we are developing both interactive and automated 3D analysis of neutron data by leveraging NVIDIA’s Omniverse technology. We have implemented machine learning techniques to automatically identify Bragg peaks and separate them from diffuse backgrounds and analyze the crystalline lattice parameters for further analysis. A novel CNN architecture has been developed to identify anomalous background from detector instrumentation for dynamical cleaning of measurements. Our approach allows scientists to visualize and analyze data in real-time from a conventional browser, which promises to improve experimental operations and enable new science. We have deployed a cloud based server, leveraging Sirepo technology, to make these capabilities available to beamline users in the control room.
Paper: THPG84
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG84
About: Received: 15 May 2024 — Revised: 04 Jun 2024 — Accepted: 04 Jun 2024 — Issue date: 01 Jul 2024
THPR06
Update on automated RF-conditioning utilizing machine learning
3488
The conditioning of room temperature cavities is an exhausting process. To prevent damage to the cavity and auxiliary equipment, this potentially long process needs constant supervision or extensive safety precautions. Additionally, the unpredictability of every new conditioning makes the development of effective classical algorithms difficult. To reduce the workload for everyone involved and to increase the efficiency of the conditioning process, it was decided to develop a machine learning algorithm with the goal of fully automated conditioning in mind. To reach this goal, it is planned to train the model on the data of already conducted conditionings of room temperature cavities, a virtual cavity and several more conditionings to be conducted soon. In this paper, the status of development, problems and challenges as well as the planned future progression shall be summarized.
Paper: THPR06
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR06
About: Received: 13 May 2024 — Revised: 17 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
THPR16
Design of a spin rotator for the ISIS Super-MuSR beamline
3520
The spin rotators (SR) are DC electromagnetic devices that produce a homogeneous magnetic field to rotate the spin of the muons in flight, which is counterbalanced by a matched perpendicular electric field to avoid the bending of the muon beam trajectory. Two identical SR will be used in the new Super-MuSR beamline to rotate the muon spin by up to 34º per device relative to the beam direction, enabling higher transverse field muon measurements and other experiments not currently possible in the present ISIS MuSR beamline. The fundamental electromagnetic (EM) design of the SR is presented in this paper, both for the magnet and the high voltage vessel. The optimization of the electric and magnetic fields shape and strength is presented including fundamental hand calculations, 2D/3D models and particle tracking simulations. The high voltage feedthroughs and the electrode insulating supports were thoroughly designed to reduce the breakdown probability. A sensitivity study was also developed to estimate the manufacturing tolerances, but it is not presented in this paper.
Paper: THPR16
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR16
About: Received: 30 Apr 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
THPR24
Operation status of FRIB wedge systems and plan for power ramp up
3545
At the Facility for Rare Isotope Beams (FRIB) Advanced Rare Isotope Separator (ARIS), wedges are critical devices to achieve rare isotope beam production. Different ions experience a different amount of slowing down by the wedges, which leads to a spatial separation of ion species and enables separation/purification of the secondary isotope beam. As of December 2023, wedge systems have successfully supported FRIB commissioning for over 4,000 hours. Nearly 60 unique wedges were utilized which were implemented during 15 wedge maintenance periods. Material selection, unique wedge designs for beam tuning, secondary wedge design, and diagnostic wedge design developments will be discussed in this paper. The current wedge devices will support primary beam operations to a power level of 65 kW, as evaluated by analysis. Development is underway to achieve a higher power wedge system, capable of 400 kW with full remote handling capacity. Further development plans include a variable wedge system to reduce maintenance time and increase ARIS tuning flexibility.
Paper: THPR24
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR24
About: Received: 08 May 2024 — Revised: 18 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
THPR25
Design automation of pre-separator wedges for FRIB advanced rare isotope separator
3549
At the Facility for Rare Isotope Beams (FRIB) unique pre-separator wedges are required for each experiment. As the number of experiments and wedges needed increases every year, reduction in design time and increase in accuracy is critical (FY23 utilized 40 unique wedges, FY24 approx. 60 are planned, and eventually 100 annually). Design automation is achieved by DriveWorksXpress, which reduced design/drafting time by 60%. A form was created with parameters (inputs) listed for each component of the wedge assembly (e.g., wedge height, wedge on axis thickness, wedge angle, etc.). The dimensions and file properties of each component are then able to reference the input values for each parameter from the form and automatically adjust the model and assembly accordingly. Automation on drawing drafting is achieved at the same time. The reduction in design time resulted in completing the design task more efficiently. A reduction in design error and human error was also observed, reducing manufacturing down time and effort required during the release process. These benefits have streamlined the mechanical design process for the pre-separator wedges.
Paper: THPR25
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR25
About: Received: 09 May 2024 — Revised: 23 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
THPR29
High fidelity numerical modelling and condition monitoring applied to septum magnets at CERN
3556
The CERN Accelerator Beam Transfer group has recently launched a study to investigate the life cycles of pulsed septum magnets. The development is aiming to enhance the prediction of anomalies, leading to reduced life cycles of these beam transfer equipment. For this reason, the standard vacuum operated, direct drive septa magnet has been chosen to investigate critical design features. In the initial project phase, a so called High-Fidelity (HF) numerical simulation has been carried out, providing insight on critical components, like brazed joints, reducing the fatigue life. In parallel a dedicated test setup with state-of-the-art instrumentation has been developed, allowing to confirm the predicted system response. The novel approach for the beam transfer equipment will allow to review presently established design criteria. In a further iteration, the project is now aiming to demonstrate an anomaly detection and their prediction based on novel machine learning techniques. This paper presents the initial phase of developing the HF model, as well as the results of the instrumented magnet tests which will be compared to results from the numerical simulations.
Paper: THPR29
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR29
About: Received: 14 May 2024 — Revised: 17 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
THPR34
First implementation of RF-KO slow extraction at COSY
3568
Radio Frequency Knock Out (RF-KO) resonant slow extraction is commissioned at the Cooler Synchrotron (COSY) Jülich for the first time to extract the stored beam and deliver spills with constant particle rates to the experiments. Therefore, transverse RF excitation generated with a software-defined radio is applied to control the extraction rate. A built-in feedback system adjusts the excitation amplitude to maintain the desired extraction rate. To suppress fluctuations of the particle rate on timescales of milliseconds and below, an optimization algorithm is used to tune the RF excitation signals. The method was used extensively during the final run of COSY in 2023, reliably delivering stable beams to various users.
Paper: THPR34
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR34
About: Received: 13 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
THPR36
Automated anomaly detection on European XFEL klystrons
3575
High-power multi-beam klystrons represent a key component to amplify RF to generate the accelerating field of the superconducting radio frequency (SRF) cavities at European XFEL. Exchanging these high-power components takes time and effort, thus it is necessary to minimize maintenance and downtime and at the same time maximize the device's operation. In an attempt to explore the behavior of klystrons using machine learning, we completed a series of experiments on our klystrons to determine various operational modes and conduct feature extraction and dimensionality reduction to extract the most valuable information about a normal operation. To analyze recorded data we used state-of-the-art data-driven learning techniques and recognized the most promising components that might help us better understand klystron operational states and identify early on possible faults or anomalies.
Paper: THPR36
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR36
About: Received: 16 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
THPR37
Towards unlocking insights from logbooks using AI
3579
Electronic logbooks contain valuable information about activities and events concerning their associated particle accelerator facilities. However, the highly technical nature of logbook entries can hinder their usability and automation. As natural language processing (NLP) continues advancing, it offers opportunities to address various challenges that logbooks present. This work explores jointly testing a tailored Retrieval Augmented Generation (RAG) model for enhancing the usability of particle accelerator logbooks at institutes like DESY, BESSY, Fermilab, BNL, SLAC, LBNL, and CERN. The RAG model uses a corpus built on logbook contributions and aims to unlock insights from these logbooks by leveraging retrieval over facility datasets, including discussion about potential multimodal sources. Our goals are to increase the FAIR-ness (findability, accessibility, interoperability, and reusability) of logbooks by exploiting their information content to streamline everyday use, enable macro-analysis for root cause analysis, and facilitate problem-solving automation.
Paper: THPR37
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR37
About: Received: 16 May 2024 — Revised: 16 May 2024 — Accepted: 16 May 2024 — Issue date: 01 Jul 2024
THPR39
Review of known extraction kickers
3587
The following paper embarks on an in-depth exploration of extraction kickers employed at some of the most renowned particle physics and neutron science facilities worldwide. Specifically, we delve into the extraction kickers utilized at the Spallation Neutron Source, Fermi National Accelerator Laboratory, Los Alamos Neutron Science Center, and delve into the novel inductive adder structures. These facilities represent the forefront of scientific research, housing state-of-the-art technologies and extraction kicker systems that play a fundamental role in advancing our understanding of particle physics, neutron science, and related domains. Throughout the paper, we will investigate the design principles, operational intricacies, and technological innovations associated with these extraction kickers. By analyzing existing research and scholarly works, we aim to provide a comprehensive overview of the unique challenges and advancements encountered at each facility.
Paper: THPR39
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR39
About: Received: 10 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
THPR41
Investigating pulsed slow extraction schemes at the MedAustron synchrotron
3595
The temporal characteristics of ultra-high dose rate beams delivered for FLASH research are often dictated by machine constraints, making it challenging to compare the outcomes across studies performed at different facilities. To broaden the opportunities for systematic, non-clinical FLASH research, this study explores methods to deliver beams with customizable time structures from a medical synchrotron. The studies are being performed at the center for ion beam therapy and research MedAustron and aim at extracting ultra-high dose rate proton beams in a series of pulses with adjustable dose per pulse, pulse length and pulse separation down to sub-ms levels. This contribution describes the implementation of the extraction methods explored for this application, phase displacement and radio frequency knockout extraction, and presents first measurement results. The measurement setup employs a silicon carbide detector in conjunction with a 20 MHz bandwidth amplifier, enabling intensity measurements with a resolution exceeding the synchrotron revolution period.
Paper: THPR41
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR41
About: Received: 15 May 2024 — Revised: 22 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPR42
A double multi-turn injection scheme for mixed ¹²C⁶⁺ and ⁴He²⁺ beams
3599
With a very low relative charge-to-mass ratio offset of approximately 0.065%, helium (⁴He²⁺) and carbon ions (¹²C⁶⁺) are interesting candidates for being simultaneously accelerated in hadron therapy accelerators. At the same energy per nucleon, helium ions exhibit a stopping range approximately three times greater than that of carbon ions. They can therefore be exploited for online range verification in a detector downstream of the patient during carbon ion therapy. The synchrotron-based MedAustron Ion Therapy Center provides the opportunity to study the feasibility of such a mixed beam-based in-vivo range verification system due to the availability of 120-402.8 MeV/u carbon beams and the ongoing commissioning of 39.8-402.8 MeV/u helium beams. One possibility for creating this mixed beam is accelerating ⁴He²⁺ and ¹²C⁶⁺ sequentially through the LINAC and subsequently “mixing” the ion species at injection energy in the synchrotron with a double injection scheme. This contribution introduces this newly proposed injection scheme, outlines challenges and presents first feasibility estimates obtained through measurements and particle tracking simulations.
Paper: THPR42
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR42
About: Received: 13 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
THPR46
FLASH proton therapy facility design with permanent magnet
3613
We present a design of the proton FLASH radiation therapy facility using the Brag peak to be built at Stony Brook University Hospital at the Radiation Oncology Department. It includes an injector using a commercially available injector cyclotron (10-30 MeV), fixed field alternating (FFA) gradient beam lines, permanent magnet Fixed Field Alternating Gradient non-scaling variable transverse field fast-cycling synchrotron accelerator with unprecedented kinetic energy range between 10-250 MeV, and a permanent magnet delivery system the FFA gantry. This facility removes limitations of the present proton cancer therapy facilities allowing FLASH radiation to be performed with 40 Gy/s in 100 ms. This allows treatment with the FLASH therapy without magnet adjustments for any proton kinetic energy between 70-250 MeV. The proposal is based on already experimentally proven FFA concept at the Energy Recovery linac 'CBETA' built and commissioned at Cornell University.
Paper: THPR46
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR46
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
THPR52
Medical irradiation studies at KIT accelerators
3635
Radiation therapy is an important oncological treatment method in which the tumor is irradiated with ionizing radiation. In recent years, the study of the beneficial effects of short intense radiation pulses (FLASH effect) or spatially fractionated radiation (MicroBeam/MiniBeam) have become an important research field. Systematic studies of this type often require research accelerators that are capable of generating the desired short intense pulses and, in general, possess a large and flexible parameter space for investigating a wide variety of irradiation methods. The KIT accelerators give access to complementary high-energy and time-resolved radiation sources. While the linac-based electron accelerator FLUTE (Ferninfrarot Linac- und Testexperiment) can generate ultrashort electron bunches, the electron storage ring KARA (Karlsruhe Research Accelerator) provides a source of pulsed X-rays. In this contribution, first dose measurements at FLUTE and KARA, as well as simulations using the Monte Carlo simulation program FLUKA are presented.
Paper: THPR52
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR52
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPR63
Thermal diffusivity and acoustic properties of Nb thin films studied by time-domain thermoreflectance
3667
The thermal diffusion and acoustic properties of Nb impacts the thermal management of devices incorporating Nb thin films such as superconducting radiofrequency (SRF) cavities and superconducting high-speed electronic devices. The diffusion and acoustic properties of 200-800 nm thick Nb films deposited on Cu substrates were investigated using time-domain thermoreflectance (TDTR). The films were examined by X-ray diffraction, scanning electron microscopy, and atomic force microscopy. The grain size and thermal diffusivity increase with film thickness. The thermal diffusivity increased from 0.100± 0.002 cm2s-1 to 0.237± 0.002 cm2s-1 with the increase in film thickness from 200 nm (grain size 20±6 nm) to 800 nm (grain size 65±16 nm). Damped periodic photoacoustic signals are detected due to laser heating generated stress in the Nb film, which results in an acoustic pulse bouncing from the Nb/Cu and the Nb/vacuum interfaces. The period of the acoustic oscillation gives a longitudinal sound velocity of 3637.3 ms-1 inside the Nb films, which is in good agreement with the values reported in the literature.
Paper: THPR63
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR63
About: Received: 07 May 2024 — Revised: 17 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
THPR83
Electrical fire safety assessment of the synchrotron accelerator experimental station in NSRRC
3704
The synchrotron facility and experimental station in the National Synchrotron Radiation Research Center (NSRRC) uses many electrical appliances, the improper use of which can cause fires, resulting in property damage and personal injury. Therefore, the usage of these electri-cal appliances must be assessed. This study conducted a comprehensive inspection and evaluation of the electrical appliances used in NSRRC, including extension cords and electrical connections; this was done to not only reduce the risk of fire but also emphasize the importance of electrical safety habits. We connected an extension cord reel in the NSRRC to a pump or a dehumidifier and used a thermal imaging cam-era to measure the temperature of the cord and these two appliances. We tested the extension cord reel when it was coiled up in the reel and straightened to determine which electrical appliances or extension cord states were prone to high temperatures and fires. The results showed that the extension cord was 18–20°C hotter when it was coiled than when it was straight. Therefore, we recommend that at least two-thirds of the length of the extension cord should be extended out of the reel when it is used.
Paper: THPR83
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR83
About: Received: 05 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
THPR84
Development of a quality test platform for solid-state power amplifiers in NSRRC
3707
To rule out Solid-State Power Amplifier (SSPA) modules with defects due to handmade and reduce time cost of maintenance for deployed modules, it is essential to establish a comprehensive testing platform that includes a complete quality control system. In this study, we developed a platform with function of manipulating driving power and shutting down when failures are detected.
Paper: THPR84
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR84
About: Received: 14 May 2024 — Revised: 16 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
THPS04
Design and testing of high stability power supply for high energy photon source
3729
The High Energy Photon Source (HEPS) is the fourth-generation synchrotron photon source. Compared with the third-generation synchrotron photon source, the brightness is 100-1000 times higher, and the electron emittance of the storage ring is low to the diffraction limit of light. Through physical calculations, it is required that the stability of the storage ring quadrupole magnet power supply be better than 10ppm, and the accuracy of output current be better than 80ppm. This high demand for technical parameter poses a challenge to the development of high precision and stability power supplies. The main circuit topology of the power supply adopts a phase shifted full bridge soft switching scheme, which avoids interference caused by switching noise and improves power stability and efficiency. The high-precision digital power supply controller based on FPGA improves the sampling speed and control accuracy of the power supply, and the constant temperature control circuit ensures that the output current of the power supply meets the requirements of HEPS for power supply performance. In the batch testing section, a testing facility was built to test the stability, accuracy, repeatability, voltage ripple, and other parameter of high precision and stability power supplies. After a year and a half of testing, the performance tests of 1066 power supplies, including linear accelerators power supplies, booster power supplies, storage rings power supplies, dipole and quadrupole combined power supplies, dipole and quadrupole power supplies, were completed. The results all met and exceeded the design specifications. The HEPS high precision and stability power supply meets the design requirements in terms of current stability, accuracy, repeatability, voltage ripple, and other aspects. The batch test results show that the power supply performance using the full bridge phase shifting soft switching technology combined with high-precision digital controller scheme is excellent, and the power supply consistency is good, providing a guarantee for the successful operation of HEPS in the future.
Paper: THPS04
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS04
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPS06
Real-time digital controller design based on SoC FPGA for general usage in J-PARC MR magnet power supplies
3735
Nowadays, the real-time control is more and more popular in the particle accelerator field because it is a powerful tool for stable operation and beam loss suppression in the particle accelerator. However, in the Japan Proton Accelerator Research Complex (J-PARC) Main Ring (MR), real-time control has not been widely used in magnet power supplies yet. Magnet power supplies are very easily affected by disturbances from external factors, such as environmental temperature, device aging, power grid voltage and current fluctuations, and so on. Therefore, it is worth developing a real-time digital controller with general functions for the magnet power supplies to observe and suppress these disturbances. In this paper, we propose the design of a general-purpose intelligence controller for the magnet power supply realized by a System-on-Chip (SoC) Field Programmable Gate Array (FPGA). This digital controller can also be used as a high-resolution data acquisition system, a pattern generator, and a high-precision current control system for magnet power supplies.
Paper: THPS06
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS06
About: Received: 12 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
THPS09
Development of linear power operational amplifier for TPS correction magnet power supply
3742
This paper investigates the design and implementation of a TPS correction magnet power supply using a combination of a linear power operational amplifier (PA05) and a pre-regulator voltage controller. The PA05 linear power operational amplifier features bipolar output, high internal power dissipation, and wide bandwidth. Utilizing a DCCT sensor as a current feedback element integrated with the pre-regulator voltage controller, a closed-loop current modulation circuit is formed, providing the variable voltage required by the linear power operational amplifier. We have successfully developed a prototype of a linear power operational amplifier power supply with a pre-regulator voltage controller for TPS correction magnets through these measures. Design validation is achieved through control loops, resulting in fast and stable output current performance. The output current ripple is maintained below 100 μA, and the rise time during the step response is 75 μs. During the frequency response test using a 0.1 V interference signal, the gain margin remained within -3 dB at an 11.2 kHz bandwidth, and the phase margin was within -45 ° over a range of 5.1 kHz. The long-term stability of the output current is maintained at ten ppm. Finally, a hardware prototype circuit is assembled in the power laboratory with input voltage ranging from ±24 V, an output current of ±20 A, and a maximum rated power of 240 W.
Paper: THPS09
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS09
About: Received: 05 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
THPS11
Cold plate upgrade at the SNS
3748
The Spallation Neutron Source (SNS) employed over 200 cold plates in its Injection Kicker and quadrupole power supplies for semiconductor cooling. Each cold plate consisted of an aluminum base with interconnected copper tubes that were brazed together. Unfortunately, the durability of these plates was compromised over time due to corrosion of the copper tubes by de-ionized water. This corrosion led to the formation of small pinhole leaks, which became increasingly problematic in recent years, causing more frequent leaks and subsequent operational downtime for the SNS system. To tackle this issue, a novel solution was pursued involving the incorporation of stainless-steel tubes in the redesign. Two types of cold plates underwent rigorous simulations and extensive testing. One of the redesigned cold plates demonstrated competitive performance and was identified as a feasible replacement option. Consequently, a comprehensive initiative was executed to replace all cold plates.
Paper: THPS11
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS11
About: Received: 30 Apr 2024 — Revised: 16 May 2024 — Accepted: 16 May 2024 — Issue date: 01 Jul 2024
THPS14
Measurement of ozone concentration at the BL-02A beamline hutch in the Taiwan photon source for ensuring personnel safety
3758
The Taiwan Photon Source (TPS) BL-02A beamline at the National Synchrotron Radiation Research Center is a curved magnet beamline designed for white light mi-crotomography experiments, wherein biological samples are irradiated with high-energy white light for structural analysis. Experimenters frequently complain of odors when entering the end-station Hutch to change samples, which may be attributed to high concentrations of ozone. Ozone is a toxic gas that is produced when white light radiation reacts with oxygen in the air. Therefore, analyz-ing the ozone concentration distribution within the Hutch is necessary to evaluate safe windows of time for personnel to enter and the type of personal protective equipment that should be used. The TPS operates at a stored energy and current of 3.0 GeV and 500 mA, respectively, with ventilation air condi-tioning turned off in the beamline Hutch. We measured ozone concentrations in regions of white light exposure at the front end (15 cm) and rear end (13.5 cm) of the Hutch, with the light source turned on for 300 s and off for 300 s. We placed the detector at different distances above, below, and to the right of the beam center. Our results demonstrated that more ozone was produced when white light was exposed for a longer duration. At any given distance, the highest amount of ozone was generat-ed above the beam center, followed by to the right side and below the beam center. These findings can serve as a reference for evaluating the health and safety of research-ers exposed to ozone in their work environments.
Paper: THPS14
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS14
About: Received: 05 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
THPS21
Strain measurements of the Apple-X SABINA undulator with fiber Bragg grating
3777
The SABINA project will add a user facility to SPARC_LAB at INFN in Frascati (Rome). For the THz line, an electron beam is transported to the APPLE-X undulators to produce photon pulses in the ps range, with energy of tens of µJ, with linear or elliptical polarization. Each undulator has four magnetic arrays that can be moved radially simultaneously to set the operating gap. Two arrays can also move longitudinally for phase displacement. A structural analysis of this unique mechanical structure has been performed by the production company (KYMA S.p.a) to ensure good field quality and beam trajectory. To support those, a set of tests has been performed with FBG acting as strain sensors in Frascati. An FBG is a phase grating inscribed in the core of a single-mode fiber, whose Bragg-diffracted light propagates back along the fiber. Any deformation of the grating affects its pitch, which changes the diffracted Bragg wavelength thus giving information about the occurred deformation. Application of the technique at the state-of-the-art level allows to perform strain measurements with 1 µStrain resolution. Such analysis and results will be presented in this contribution.
Paper: THPS21
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS21
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
THPS23
Design and fabrication of the automation system in TLS BL07A end station
3785
The end station for TLS beamline 07A (BL07A) primarily serves industrial applications, catering to various sample inspection requirements within the industry in multiple modes. In the past, manual switching of modes for different experiments was time-consuming, requiring the re-installment a lot components and taking long time to readjust the gas proportion for different samples. To enhance the efficiency of the BL07A experimental station, an automated design has been implemented, utilizing multiple self-made motorized platforms. Another crucial aspect for improved experimental efficiency is the use of a combination of vacuum pumps, flow meters, and electromagnetic valves for gas replacement system, significantly reducing the time needed for this process. The automated system is currently operational, reducing the operation time for experimental equipment switching from several hours to two minutes. The execution time for the gas replacement process has also been drastically reduced from 100 minutes to 5 minutes.
Paper: THPS23
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS23
About: Received: 10 May 2024 — Revised: 16 May 2024 — Accepted: 16 May 2024 — Issue date: 01 Jul 2024
THPS29
Simulation study of nanosecond pulse power based on gyromagnetic nonlinear transmission line
3800
On-axis injection mode is planned to use in the Southern Advanced Photon Source (SAPS), which requires high quality to injection pulsed power supply. Gyromagnetic nonlinear transmission line (GNLTL) is introduced as a pulse compressor to meet the needs for pulse width. In this paper, 3-D finite element model is established based on Landau-Lifshitz-Gilbert equation and Maxwell’s equations. The influence of geometrical sizes and bias magnetic field to output pulse is analyzed for better design of NLTL. A prototype was built with nanosecond pulse width and sub-nanosecond rise time to verify the simulation.
Paper: THPS29
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS29
About: Received: 15 May 2024 — Revised: 18 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
THPS30
Design and characterization of adjustable-length pulse generator for beam kicker system
3803
The contemporary advancement in particle accelerator technology necessitates precise control over beam manipulation for various experimental and industrial applications. One pivotal aspect of this control resides in the generation and modulation of high-voltage pulse to manipulate the trajectory and behavior of particle beams within the accelerator systems. This extensive study delves into the design, development, and characterization of an adjustable-length pulse generator specifically tailored for a beam extraction kicker system, which is employed to navigate the beam out of the photon storage ring. The primary aim of this research is to engineer a versatile and reliable pulse-length modulation mechanism for a high-voltage pulse generation, which is capable of producing adjustable pulses with ultra-fine precision to meet the demanding requirements of beam manipulation within the accelerator setup. The system's design encompasses a meticulous integration of electronic components, waveform shaping modules, and control mechanisms to achieve the desired output.
Paper: THPS30
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS30
About: Received: 15 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
THPS31
A 50 kV pulse generator for fast kickers
3806
Brookhaven National Laboratory has recently been selected as the site for the Electron-Ion Collider (EIC). The EIC will consist of two intersecting accelerators, one producing an intense beam of electrons, the other a high-energy beam of protons or heavier atomic nuclei, which are steered into head-on collisions. One of the sections of the EIC beamline will require a hadron injection fast kicker system. RadiaBeam is developing GaN-based pulser with ±50 kV voltage amplitude, <4 ns rise and fall times, 40 ns pulse width. In this paper, we discuss the development progress.
Paper: THPS31
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS31
About: Received: 16 May 2024 — Revised: 21 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPS32
Ultrafast high-voltage kicker system hardware for ion clearing gaps
3809
Ionization scattering of electron beams with residual gas molecules causes ion trapping in electron rings, both in a collider and electron cooling system. These trapped ions may cause emittance growth, tune shift, halo formation, and coherent coupled bunch instabilities. In order to clear the ions and prevent them from accumulating turn after turn, the gaps in a temporal structure of the beam are typically used. Typically, the gap in the bunch train has a length of a few percent of the ring circumference. In those regions, the extraction electrodes with high pulsed voltages are introduced. In this paper, we present the design consideration and initial test results of the high-voltage pulsed kicker hardware that includes vacuum device and pulsed voltage driver, capable of achieving over 3 kV of deflecting voltage amplitude, rise and fall times of less than 10 ns, 100 ns flat-top duration at 1.4 MHz repetition rate.
Paper: THPS32
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS32
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPS35
A novel pulse compressor with dielectric assistance
3813
A compact pulse compressor with dielectric assistance structure is proposed and simulated. The novel pulse compressor adopts a spherical resonant cavity design with dual-mode polarization mode. A dielectric sphere added at the centre of the spherical cavity can reduce the volume and weight of the pulse compressor and improve the unloaded quality factor of the cavity. A C-band compact storage cavity model is designed and simulated on ANSYS HFSS working on 5.712 GHz. The dielectric permittivity of the dielectric sphere is 9, and the dielectric tangent loss is 0.00001. The simulation of the dielectric-assist resonant cavity with an inner diameter of 34 mm indicates an unloaded quality factor about 72000.
Paper: THPS35
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS35
About: Received: 14 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
THPS42
Pressure spike in the LBNF absorber core’s gun drilled cooling channel from an accident beam pulse
3830
The LBNF Absorber consists of thirteen 6061-T6 aluminum core blocks. The core blocks are water cooled with de-ionized (DI) water which becomes radioactive during beam operations. The cooling water flows through gun-drilled channels in the core blocks. The cooling water is supplied by the LBNF Absorber Radioactive Water (RAW) cooling system which is designed as per ASME B31.3 Normal Fluid Service [1]. An uninhibited beam accident pulse striking the water channels was identified as a credible accident scenario. In this study, it is assumed that the beam pulse hits the Absorber directly without interacting with any of the other upstream beamline components. The beam parameters used for the LBNF beam are 120 GeV, 2.4 MW with a 1.2 s cycle time. The accident pulse lasts for 10 µs. The maximum energy is deposited in the 3rd aluminum core block. For the sake of simplicity, it is assumed that the accident pulse strikes the 1 in. ID water channel directly. The analysis here simulates the pressure rise in the water during and after the beam pulse and its effects on the aluminum piping components that deliver water to the core blocks. The weld strengths as determined by the Load and Resistance Factor Design (LRDF) and the Allowable Strength Design (ASD) are compared to the forces generated in the weld owing to the pressure spike. A transient structural analysis was used to determine the equivalent membrane, peak, and bending stresses and they were compared to allowable limits.
Paper: THPS42
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS42
About: Received: 30 Apr 2024 — Revised: 17 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
THPS43
Comparative study of decay heat calculations with FLUKA and MCNP/CINDER2008
3833
In designing a high-power tungsten target, decay heat driven temperature rise in the spallation volume is a safety concern during maintenance and in loss of coolant accidents. As tungsten hydrates and becomes volatile in steam at above 800 ◦C, it is important to keep the target temperature below this threshold when active cooling is unavailable. Decay heat in a target is calculated with particle transport simulation codes combined with transmutation codes. The calculated decay heat usually differs depending on the nuclear cross sections and the decay particle transport models built in the code architecture. In this paper, we calculated decay heat of a water-cooled tungsten target using popular particle transport codes, FLUKA and MCNP6® paired with CINDER2008 and compared the results. The target-moderator-reflector (TMR) system is modeled with a water-cooled solid tungsten target, water premoderators, liquid hydrogen cold moderators and beryllium reflectors. Water-cooled stainless-steel shielding is modeled around the TMR system. The tungsten volume is clad with a thin layer of erosion/corrosion resistant material. This study provides information about the uncertainty range in decay heat prediction of high-power spallation targets for hazard analysis.
Paper: THPS43
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS43
About: Received: 15 May 2024 — Revised: 18 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
THPS45
Proton beam power limits for stationary water-cooled tungsten target with different cladding materials
3841
The proton beam power limit for a solid-tungsten spallation target is largely determined by beam induced thermomechanical structural loads and decay heat power deposition, while its lifetime is limited by radiation damage and fatigue life of the target materials. In this paper, we studied the power limits of a stationary water-cooled solid tungsten target concept. Tantalum clad tungsten was considered as a reference case. Being a low activation material, zircaloy 2 cladding option was studied and its decay heat driven power limit was compared with the reference case. Zirconium alloys have proven operations records in spallation target and nuclear fission environments, supported by materials data obtained from post irradiation examinations. Recent study also demonstrated feasibility of diffusion bonding zirconium to tungsten using vanadium foil inter layer. Particle transport simulations code FLUKA was used to calculate energy deposition and decay heat power deposition in the target, based on the beam parameters technically feasible at the Second Target Station of the Spallation Neutron Source at Oak Ridge National Laboratory. The energy deposition data were used for flow, thermal, and structural analyses to determine the beam intensity limit on the target concept studied. The decay heat deposition data were used to calculate the transient temperature evolution in the tungsten volumes in a loss of coolant accident (LOCA) scenario to determine its beam power limit. For a 1.3 GeV proton beam, the power limit on a stationary target was 400 kW for a tantalum clad target model and 800 kW for a zircaloy 2 clad target model.
Paper: THPS45
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS45
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
THPS48
3D integration methodologies of the accelerators at CERN
3845
The 3D design of large accelerators like the Large Hadron Collider (LHC) requires coordination among equipment, services, and infrastructures. As numerous systems are designed, procured, and installed, 3D integration studies are important steps at any stages of a project, starting from the conceptual phase with space reservations, envelopes and interfaces, followed by the technical design phase managing the detailed and simplified 3D models, and finishing by the installation phase with follow-up of discrepancies. While the first phases serve to validate the accelerator configuration and design, the installation phase is followed by a reverse engineering process to verify the ‘as-built’ configuration, representing the final actual setup of the accelerator. At CERN, the 3D integration office for the accelerators assumes responsibility for collecting, aggregating, centralizing, and checking the 3D models provided by CERN design offices such as equipment owners, electrical, civil engineering, metallic structure, transport, handling, cooling, and ventilation services. This office manages 3D space, avoiding mechanical interferences before and during the installation phase. This paper describes the CAD, PDM and PLM methodologies used for 3D integration of the accelerators at CERN, highlighting their critical aspects and specificities.
Paper: THPS48
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS48
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
THPS52
PLAN analytics for enhanced understanding of RUN3 and LS3 activities at CERN
3857
Designed as an internal tool at CERN, PLAN has a pivotal role in the centralization and macroscopic aggregation of technical intervention and enhancement activities planned within the accelerator complex. As part of a broader strategy to enhance tool utilization and extract valuable insights, a substantial endeavor during RUN3 aimed to develop and disseminate analytics derived from tool-generated data. These analytics are seamlessly accessible via a FLASK application, crafted primarily using Python and the Bokeh library, JavaScript, HTML, and CSS. Hosted internally at CERN through OpenShift, it is containerized through Docker, and subject to continuous integration via GitLab. These analytics serve versatile purposes, encompassing the quantification of activities, identification of resource constraints across departments and groups, and the provision of insights into various facilities, projects, and more. Moreover, they play an instrumental role in identifying bottlenecks and critical milestones in planning timelines. These analytics are designed to furnish management and other stakeholders with essential insights, ultimately contributing to wide-ranging improvements across CERN.
Paper: THPS52
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS52
About: Received: 14 May 2024 — Revised: 19 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPS53
Numerical analysis on a modified air conditioning system of the experimental hall at TPS
3861
It has been seven years since the Taiwan Photon Source (TPS) started to serve users in 2016. Sixteen beamlines had been installed in the first and second phases of TPS beamline project. The third phase project was also launched in 2021. Considering the experimental hall is more compact and power saving issue, our research aimed to analyze a modified air conditioning system with better cooling efficiency through Computational Fluid Dynamic (CFD) simulation. One twelfth of the TPS experimental hall and two beamlines are modeled.
Paper: THPS53
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS53
About: Received: 14 May 2024 — Revised: 16 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
THPS58
Permanent magnet resiliency in CEBAF’s radiation environment: LDRD grant status and plans
3875
As the FFA@CEBAF energy upgrade study progresses, it is important to investigate the impact of radiation exposure on the permanent magnet materials to be used in the upgraded fixed field alternating gradient (FFA) arcs. To address this, Jefferson Lab has awarded a Laboratory Directed Research and Development (LDRD) grant to study the resiliency of several permanent magnet materials placed in a radiation environment similar to that in which they are expected to operate. Samples of NdFeB and SmCo are to be placed alongside appropriate dosimetry in a variety of radiation environments in the beam enclosure and experimental halls at CEBAF. The magnet degradation will be measured, and extrapolated to the higher energies expected during operations after the energy upgrade. This document will describe the current status of the LDRD study, as well as describe the upcoming plans. It will also direct the readers to other proceedings which further detail the work thus far.
Paper: THPS58
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS58
About: Received: 10 May 2024 — Revised: 16 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
THPS59
Design and instrumentation for permanent magnet samples exposed to a radiation environment
3879
This work is part of a larger program to study the effects of radiation on permanent magnets in an accelerator environment. In order to be sure that the permanent magnet samples are accurately placed, measured, and catalogued we have developed a system of sample racks, holders and measuring apparatuses. We have combined these holders and measurement racks with electronics to allow a single computer to catalogue the position and intensity of the magnet measurements. We outline the design of the apparatus, the collection software, and the methodology we will use to collect the data.
Paper: THPS59
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS59
About: Received: 14 May 2024 — Revised: 17 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
THPS61
Qualification of components for installation in LHC kicker magnets
3886
LHC injection kickers (MKI) are pulsed at high voltage to achieve magnetic field pulses with fast rise time. The MKIs contain a beam screen to help shield their ferrite yoke from beam induced heating. However, additional means of mitigating beam induced heating, for the high luminosity LHC (HL-LHC) era, are required. To achieve this, the MKIs are sequentially being upgraded to low impedance versions (MKI Cool) with several critical components including (a) a 3-m long alumina tube, installed in the magnet aperture, used to hold screen conductors that help shield the magnet yokes from beam induced heating; and (b) an RF damper which moves beam induced power from the ferrite yoke to a ferrite cylinder which is part of the damper. This paper discusses the measurements carried out to qualify these components for installation in an MKI Cool. In addition, for the alumina tube, the interpretation of the measurement data is discussed together with the optimisation of the angular orientation of the tube in the magnet aperture.
Paper: THPS61
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS61
About: Received: 14 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
THPS62
Perspectives and recent achievements on additive manufacturing technologies for accelerators
3890
This paper reports the exploratory studies on advanced accelerator technologies performed within the I.FAST (Innovation Fostering in Accelerator Science and Technology) EU project, and in particular the key results of the additive manufacturing Task 10.2 – “Additive Manufacturing – applications and potential developments” and Task 10.3 – “Repair of damaged accelerator components by AM technologies”. This includes results of two surveys targeted to the accelerator community: a) on current additive manufacturing applications in accelerators and expected new developments, b) on current additive manufacturing repair technologies for accelerator and list of possible applications. The paper is outlining potential additive manufacturing applications in accelerators and overall strategies applicable to accelerator components repairs benefiting from additive manufacturing technology.
Paper: THPS62
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS62
About: Received: 18 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
THPS70
3D printed beam correctors
3908
Starting from 2018 we have designed and created 3D printed beam correctors using two different types of FDM materials, Ultem and ASA. The design was defined based on the ergonomics of the existing machine parts, avoiding radial and longitudinal mechanical interference, and the magnetic performances to be produced. The size and configuration of the resulting windings influenced the choice of the most suitable FDM material for the purpose. In total we present 3 different prototype models which, in addition to demonstrating the ability to produce the design performances, are currently used on the SPARC-Lab Experiment in our INFN National Laboratories in Frascati.
Paper: THPS70
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS70
About: Received: 14 May 2024 — Revised: 18 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
FRYD3
Particle colliders: options for the US and internationally
3944
In the US high energy planning process more than 30 colliders were considered. This talk gives an overview of these colliders and emphasized the strength of the various approaches.
Paper: FRYD3
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-FRYD3
About: Received: 14 May 2024 — Revised: 16 May 2024 — Accepted: 16 May 2024 — Issue date: 01 Jul 2024