MOPM
-
Monday Poster Session: MOPM
08 May 2023, 16:30 -
18:30
MOPM001
Four-rows APPLE-Knot undulator on HEPS
976
The High Energy Photon Source (HEPS) is a 4th generation synchrotron radiation source being built in China. An APPLE-Knot undulator with a new configuration is designed for the XCMD beamline of the HEPS. It is the first time to apply four-row APPLE-Knot undulator in storage ring based light sources. The main differences between the novel design and the conventional design of the APPLE-Knot undulators are discussed. Furthermore, the influences of the APPLE-Knot undulator on storage ring optics, as well as the dynamic effects during the process of gap variation at different polarization modes, are investigated and will be introduced in this paper.
Paper: MOPM001
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM001
About: Received: 04 May 2023 — Revised: 05 Jun 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
MOPM002
Progress of physics studies and commissioning preparations for the High Energy Photon Source
980
The High Energy Photon Source (HEPS) is a 34-pm, 1360-m storage ring light source being built in the suburb of Beijing, China. The construction of HEPS started in mid-2019. Later, to deal with challenges emerging from the technical and engineering designs, the HEPS accelerator physics design was modified and had been finalized in 2020. Afterwards, studies on related physics issues were updated and have been basically finished. Besides, preparing studies for commissioning of the HEPS Linac, booster and storage ring were started almost at the same time, and are still underway. The commissioning of the Linac has been launched since early of 2023. In this paper, we will briefly introduce the updated studies on related physics issues and present the results of the Linac commissioning.
Paper: MOPM002
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM002
About: Received: 25 Apr 2023 — Revised: 07 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
Girder and support system for the Iranian Light Source Facility
Iranian light source facility (ILSF) is a 4th generation synchrotron with a nominal horizontal emittance of 270 pm.rad. Storage ring magnet-girder support stability is essential for beam stability. The support system of storage ring girders is essential to achieve the accuracy of adjustment and vibration stability. After studying different girder support systems and considering the stability requirements of the ILSF machine, the wedge and screw support system was selected for vibration analysis. In the vibration analysis, the wedge system was better than the screw one. The wedge system improves the magnet-girder stability, which caused an acceptable increase in the vibration frequency modes in the modal analysis.
MOPM007
Application of three families of sextupoles at the KARA ring of Karlsruhe Institute of Technology
984
A third family of sextupole magnets was recently in-corporated at the KIT storage ring KARA (Karlsruhe Research Accelerator). Computer studies of beam dy-namics were performed with an objective to estimate benefits of operation with three sextupole families and possibility of new configuration of ring lattice to con-trol slope and curvature of momentum compaction factor as function of energy offset of particles in a bunch. Adjustment of high order terms of alpha would allow to shorten bunch further down. Simulations of KARA ring model have been bench-marked on exist-ing experiments at Metrology Light Source (MLS) in Berlin (Germany) and SOLEIL (France).
Paper: MOPM007
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM007
About: Received: 21 Apr 2023 — Revised: 11 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
MOPM009
Status of the ALS-U accumulator ring installation
988
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. The project has recently received federal approval to start construction for the new storage ring. The accumulator ring (AR) has received early funding and is currently being installed in the ALS facility during its regularly planned shutdowns. This paper describes the status of the accumulator ring installation.
Paper: MOPM009
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM009
About: Received: 05 May 2023 — Revised: 08 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
MOPM010
First results of automated startup and commissioning procedures at the Advanced Light Source
991
Rapid commissioning and automated start up procedures are crucial for many upcoming 4th generation storage ring light sources as their downtime demands are very challenging given their increased operational complexity. Detailed commissioning simulations as a tool of error analysis are not only used to guide the design process of new machines but also a prerequisite to implement an automated commissioning and start up procedure for the final machine. The current ALS can be used effectively to test the developed automated commissioning procedures for the ALS Upgrade because the lattice is very similar to the ALS-U Accumulator Ring, of which detailed commission simulations have been carried out. In this study we present first results including first turn beam threading and turn by turn beam based alignment procedures.
Paper: MOPM010
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM010
About: Received: 07 May 2023 — Revised: 07 Jun 2023 — Accepted: 21 Jun 2023 — Issue date: 26 Sep 2023
MOPM011
First results of the multipole injection kicker in the MAX IV 1.5 GeV ring
994
A Multipole Injection Kicker (MIK) has been successfully designed, constructed, installed and commissioned with beam in the MAX IV 1.5 GeV ring. This device allowed reaching injection efficiencies as high as those obtained with the previously used conventional dipole injection kicker scheme, while at the same time providing an order of magnitude reduction in the perturbations to the stored beam resulting from the injection process. In addition, the device has had a major positive impact in allowing effective top-up injection under the strong optics perturbations generated by long-period elliptically polarizing undulators. In this paper we describe the first operations with the device and detail the process of optimisation and commissioning.
Paper: MOPM011
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM011
About: Received: 03 May 2023 — Revised: 08 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
MOPM012
A report on a lower emittance lattice at MAX IV 3 GeV storage ring
998
At MAXIV Laboratory we are continuing the efforts to reduce the emittance of 330 pm.rad of the larger storage ring (SR) operating at an energy of 3GeV. This paper details the techniques used to improve the characterization of the optics, and to optimize the injection into the SR with an emphasis on the difficulties encountered during the process and the strategies adopted to overcome them.
Paper: MOPM012
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM012
About: Received: 03 May 2023 — Revised: 08 Jun 2023 — Accepted: 08 Jun 2023 — Issue date: 26 Sep 2023
MOPM013
Design and integration on the test station for PSM of a 300 kW transmitter
1002
A test station for the THALES 300kW transmitter PSM has been successfully constructed in NSRRC. Integrating the modules of power supply, control interface, interlock protection, and accessories into a single rack simplifies the examination procedure and makes signal observation easier. The layout and hardware realization of this test station, as well as important considerations and proper examination procedure in place to ensure safe and accurate operation are all presented in this article.
Paper: MOPM013
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM013
About: Received: 02 May 2023 — Revised: 08 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
MOPM014
Reducing floor vibration of TPS experimental hall caused by air handling units
1005
The Taiwan Photon Source (TPS) experimental facility has experienced vibration interference at approximately 16.8 Hz during experiments at the end station of the TPS 23A beamline, which was traced back to the air handling units (AHUs) located on the second floor of the outer ring area of TPS. The vibration of the AHUs not only affects the TPS beamline 23A end station but also all experimental areas. In this paper, we present two methods to reduce the floor vibration of the experimental hall caused by the AHUs. Firstly, we adjusted the operating frequency of each AHU fan to avoid resonance and reduce the vibration of the nearby experimental area floor, which can be reduced by up to 40%. Secondly, we installed additional air isolation mounts outside the AHU to further reduce the impact of the fans on floor vibrations, which resulted in a reduction of vibration transmission by about 30%. Our findings provide useful information for those dealing with vibration interference caused by AHUs and can help improve the experimental accuracy and efficiency in similar facilities.
Paper: MOPM014
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM014
About: Received: 02 May 2023 — Revised: 08 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
MOPM015
Beam-based alignment of beam position monitors at SLS 2.0
1008
Large initial beam position monitor (BPM) offsets have to be reduced by one order of magnitude by means of beam-based calibration (alignment) (BBA) in order to match the element-to-element magnet alignment error. At SLS 2.0 the BBA will be performed with respect to adjacent auxiliary quadrupole magnets, which are also employed for optics and tune correction. Different static and dynamic techniques can be applied to determine the offsets. The error of the individual measurements needs to be at the micrometer level to guarantee the necessary reproducibility of position and angle at the beamline source points on medium- and long-term time scales.
Paper: MOPM015
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM015
About: Received: 04 May 2023 — Revised: 06 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
MOPM016
Machine impedance calculation and impedance optimization of vacuum components in SLS 2.0
1011
For a reliable determination of the single bunch stability threshold, the broadband impedance budget needs to be analyzed for all resistive and inductive contributions. The completely new design of the arc vacuum chamber of SLS 2.0 with respect to SLS - now with a reduced beam pipe diameter, and coated with layers of copper and NEG - requires special focus on the resistive wall impedance. Higher Order Modes (HOMs) of vacuum components were also investigated. Since they stay trapped in specific positions of the ring, they can be the source of power heating and related mechanical stress, as well as the cause of Coupled Bunch Instabilities (CBI). The impact of the HOM impedance spectrum can become very important, notably if the device responsible of the resonance recurs several times in the ring or if it is located at positions with high beta values. We show some examples of HOM analysis and their related optimization, which were adopted for cavities appearing also in valves, bellows and diagnostic components.
Paper: MOPM016
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM016
About: Received: 02 May 2023 — Revised: 08 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
MOPM017
Overview of the collective effects in SLS 2.0
1015
The Swiss Light Source (SLS) will shut down in October 2023, entering the dark time period for installation of the upgraded SLS 2.0 synchrotron. The commissioning of the new electron storage ring is planned for early 2025. The upgraded storage ring features a lattice based on modern 7-bend achromats with lower momentum compaction factor, NEG coated vacuum pipes of smaller aperture and an increased beam-energy from 2.4 GeV to 2.7 GeV. To guarantee full performance, a careful analysis of the effects induced by the machine broadband and geometrical impedances and ions is mandatory. In addition to the potential well distortion due to the wake fields, the analysis must also include the transient beam-loading effects on the bunch lengthening of the passive superconducting harmonic cavity. We provide an overview of the collective effects studied for SLS 2.0, including single bunch instabilities from the broadband impedance budget, coupled bunch analysis and ion effects. For each kind of such instabilities, the main threshold curves are presented, as well as the related safety margins of operation and the tracking procedures followed.
Paper: MOPM017
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM017
About: Received: 02 May 2023 — Revised: 09 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM018
SLS 2.0 machine protection
1019
The beam abort system for the current Swiss Light Source (SLS) is based on inverting the RF phase to decelerate the stored beam. The losses are localised at longitudinal positions where the dispersive orbit encounters the machine aperture. For the SLS, these losses mainly occur at the septum and in the arcs. For the SLS 2.0* with its multi-bend-achromat lattice and thus much lower dispersion in the arcs, tracking simulations show that these losses are localised at superconducting super bends and in-vacuum insertion devices. Due to this unfortunate loss distribution and the fragile vacuum chamber combined with the small beam size and stored beam energy of 1 kJ, a more controlled beam abort is desired. In case of an RF failure, the beam abort system must dump the beam safely before the critical dispersive orbit is reached. A fast beam dump controller with dedicated inputs for fast systems such as the low-level RF and fast feedback systems is foreseen for triggering the required emergency beam dump. The majority of the well over 6000 machine interlock signals will be monitored by the slow, programmable-logic-controller-based machine interlock system (MIS). For the MIS the sheer amount of signals poses a challenge.
Paper: MOPM018
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM018
About: Received: 02 May 2023 — Revised: 08 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM020
SLS 2.0 storage ring components overview before installation
1023
The Swiss Light Source SLS will have a 15 months long shutdown starting in October 2023 in order to install the new storage ring SLS 2.0. While the procurement of large series of components like magnets, power supplies, RF, vacuum chambers, … has started, the design of more specific components like the thin septum, undulators or collimators, is close to completion. The main difficulties and challenges of SLS 2.0 are common to other diffraction limited storage rings: cross talk issues due to the very short distances between magnets and especially with permanent magnets, heat dissipation issues in the small aperture vacuum chambers due to synchrotron radiation and RF heating and in general beam instabilities issues due to wakefields perturbations. Components have been designed to withstand these constrains and this paper will give an overview of the key components design and first tests before installation.
Paper: MOPM020
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM020
About: Received: 01 May 2023 — Revised: 05 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
MOPM021
Feasibility of round beams in SLS 2.0
1027
Sharing of emittances between transverse planes has potential benefits in storage ring light sources. The larger vertical emittance significantly increases the Touschek lifetime, while the smaller horizontal emittance helps to mitigate the loss in brightness at high photon energies due to the larger vertical beam size and divergence. A fully coupled beam is considered as an optional operation mode for the SLS 2.0, should a longer beam lifetime be required. In this paper, we investigate the feasibility of having round beams in SLS 2.0 by operating on the linear difference resonance. We analyze the impact on the linear- and nonlinear performance of the machine, in particular the impact on Touschek lifetime when all apertures are included.
Paper: MOPM021
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM021
About: Received: 02 May 2023 — Revised: 06 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM022
TRIBs simulations for SLS 2.0
1031
The concept of Transverse Resonance Island Buckets (TRIBs) has recently gained attention in the storage ring light source community, and has found usage to, e.g., serve timing users and can enable fast polarity switching of the light in undulators. This contribution introduces two options for creating TRIBs in SLS 2.0 using either 3Qx or 4Qx resonances. Options for control of the islands using sextupoles and octupoles in SLS 2.0 are evaluated. The optics and equilibrium emittance within the islands are calculated and checked using tracking simulations. Furthermore, the diffusion of particles from the islands due to radiative effects and Touschek scattering is discussed.
Paper: MOPM022
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM022
About: Received: 02 May 2023 — Revised: 06 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
Linear Canonical Transform Library for Fast Coherent X-Ray Wavefront Propagation
X-ray beamlines—essential components of all synchrotron light sources—transport emitted radiation from the stored electron beam to an experimental station. One may describe the linear optics of the beamline via an ABCD matrix computed using a ray-tracing code. Furthermore, one may then include diffraction effects and arbitrary wavefront structure by using that same information in a Linear Canonical Transform (LCT) applied to the initial wavefront [1]. We describe our implementation of a Python-based LCT library for 2D synchrotron radiation wavefronts. We have thus far implemented the separable case and are implementing algorithms for the non-separable case. Our code base also includes rectangular apertures. We have tested our work against corresponding wavefront computations using the Synchrotron Radiation Workshop (SRW) code [2]. We present benchmark comparisons of LCT vs. SRW for both undulator and bending magnet sources of radiation. Finally, we describe our plans for extending this work to partially coherent radiation.
MOPM024
Slow orbit feedback correction using extra-windings at the SAGA-LS
1035
The periodic orbit change caused by the temperature fluctuation of the cooling water at the SAGA-LS storage ring was suppressed by the slow orbit feedback correction system using newly equipped extra-windings on 8 steering magnets. In recent years, the amplitude growth of temperature fluctuation of the cooling water caused maximally 40 micrometer periodic orbit change at the SAGA-LS storage ring, which affected some synchrotron radiation experiments. We equipped new extra-windings on 8 steering magnets to compensate the periodic orbit change, since the existing steering magnets for global orbit correction did not provide sufficient resolution for this small orbit change. By applying the slow orbit feedback correction system using the extra-windings, the periodic orbit change was suppressed satisfactorily. In this conference, we will also discuss about the mechanism by which the temperature fluctuation of the cooling water causes the orbit change at the SAGA-LS storage ring.
Paper: MOPM024
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM024
About: Received: 03 May 2023 — Revised: 08 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
MOPM025
Design of the pseudo single bunch mode in SPEAR3
1038
With the growing interests and new experimental development in time-resolved studies at Stanford Synchrotron Radiation Light Source (SSRL), we are motivated to develop the Pseudo Single Bunch (PSB) operational mode to address the requirements from time-resolved and regular user experiments simultaneously. In this paper, we will present the physics design for this new mode. Beam line simulations for performance evaluation of the user experiments are also reported.
Paper: MOPM025
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM025
About: Received: 02 May 2023 — Revised: 07 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
MOPM027
Seven years statistical analysis of the Siam photon source operation
1042
The Siam Photon Source, a synchrotron light source in Thailand, has undergone multiple improvements in recent years, including the installation of up to four insertion devices in the storage ring. The machine has operated at maximum capacity for a significant period of time. This study presents a statistical analysis of the machine's operation over the past seven years, including the number of beam service hours, machine downtimes, and repair times. The paper also discusses critical incidents that occurred during this period, such as faults with a booster ring bending magnet power supply, superconducting magnet cool-down problems, and issues with a cryogenic plant's liquefaction process. Furthermore, this report highlights major upgrades and improvements made over the past seven years to enhance beam quality.
Paper: MOPM027
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM027
About: Received: 28 Apr 2023 — Revised: 06 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM028
Upgrades of beam diagnostics for linac of Siam Photon Source
1046
Siam Photon Source (SPS) is an existing synchrotron light source in Thailand, which has been operated and provided synchrotron radiation for user beam service for more than 20 years. The SPS accelerator system con-sists of a 40-MeV linac, a 1.2-GeV booster synchrotron and a storage ring with double bend achromat (DBA) lattice. The linac is one of the most critical parts of the SPS machine in which its performance affects beam injection and hence to the beam service. Beam diagnostics of the SPS linac has been upgraded in order to allow better beam monitoring and become a crucial part for linac optimization to achieve higher machine performance. In this paper, upgrades of beam diagnostics of the SPS linac will be discussed.
Paper: MOPM028
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM028
About: Received: 02 May 2023 — Revised: 19 May 2023 — Accepted: 19 May 2023 — Issue date: 26 Sep 2023
MOPM030
SOLEIL machine status: operation and upgrade project
1050
The synchrotron SOLEIL is both a 2.75 GeV third-generation synchrotron light source and a research laboratory at the forefront of experimental techniques dedicated to matter analysis down to the atomic scale, as well as a service platform open to all scientific and industrial communities. We present the performance of the accelerators delivering extremely stable photon beams to 29 beamlines. The beam delivery schedule and the operation have been affected by the energy crisis. Shortages of cryogenic fluids and electronic components, coupled with a high inflation, are impacting the operation budget and the related projects. The update on the construction of the new low-energy footprint cooling station is presented. Finally, new developments and testing of prototype equipment related to the upgrade of the injector complex and the main storage ring are discussed.
Paper: MOPM030
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM030
About: Received: 06 May 2023 — Revised: 12 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
MOPM031
TDR baseline lattice for SOLEIL II upgrade project
1054
Previous TDR studies for the SOLEIL II Upgrade project have converged towards a lattice alternating 7BA and 4BA HOA type cells providing a low natural horizontal emittance value in the 80 pm.rad range at an energy of 2.75 GeV. This lattice adapts to the current tunnel geometry as well as to preserve as much as possible the present beamline positions. The new TDR lattice is an evolution including perfect straight sections alignment, better relative magnet positioning and more space for accommodating photon absorbers, BPMs and other mandatory diagnostics. The SOLEIL upgrade TDR lattice is then composed of 20 HOA cells with a two-fold symmetry, and provides 20 straight sections having five different lengths of 3.0, 3.6, 4.2, 8.0, and 9 m. This last long straight accommodates a triplet of quadrupoles to set the two low vertical beta functions and an additional canting for the two long beamlines. This paper reports the linear and the non-linear beam dynamic optimizations as well as future directions for performance improvement.
Paper: MOPM031
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM031
About: Received: 09 May 2023 — Revised: 11 May 2023 — Accepted: 23 Jun 2023 — Issue date: 26 Sep 2023
MOPM032
SPEED: Worldwide first EEHG implementation at a storage ring
1057
At DELTA, a 1.5-GeV synchrotron radiation source at TU Dortmund University, ultrashort radiation pulses are generated using CHG (coherent harmonic generation), where the interaction with laser pulses in an undulator (modulator) causes a periodic electron energy modulation within a 50-fs slice of a 2000-times longer electron bunch. A dispersive chicane creates a density modulation giving rise to the coherent emission of ultrashort pulses at harmonics of the seed pulse in a second undulator (radiator) exceeding the incoherent background from the whole bunch. In summer 2022, the electromagnetic insertion device U250, which included both undulators and the chicane, was reconfigured to demonstrate EEHG (echo-enabled harmonic generation, originally proposed for linac-based free-electron lasers) at a storage ring and to reach higher harmonics. The U250 coils were rewired to create two modulators for a twofold laser-electron interaction, two chicanes to manipulate the electron density, and the radiator, each comprising only a few undulator periods. The two seeds are a frequency-doubled Ti:sapphire laser pulse at 400 nm and its residual at 800 nm wavelength. EEHG pulses are detected using an in-vacuum grating spectrometer. In addition, the coherent emission of THz radiation is monitored. The paper presents first results of this project termed SPEED (Short-Pulse Emission via Echo at DELTA) which, to our knowledge, is the worldwide first attempt to perform EEHG at a storage ring.
Paper: MOPM032
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM032
About: Received: 03 May 2023 — Revised: 22 May 2023 — Accepted: 22 May 2023 — Issue date: 26 Sep 2023
MOPM033
Observation of coherent Terahertz bursts during low-energy operation of DELTA
1061
The electron storage ring DELTA which is operated by TU Dortmund University can be run at a reduced beam energy down to 500 MeV instead of 1.5 GeV. If a single bunch at low energy is stored, the bunch charge threshold for the emission of THz bursts is exceeded. Using a fast Schottky-barrier detector, coherent synchrotron radiation bursts of THz radiation were detected. Turn-by-turn data of the THz bursting behavior as function of the bunch charge and bursting spectrographs are presented.
Paper: MOPM033
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM033
About: Received: 03 May 2023 — Revised: 22 May 2023 — Accepted: 22 May 2023 — Issue date: 26 Sep 2023
MOPM034
Shunt impedance calculations for an in-vacuum undulator at Petra IV
1064
A new in-vacuum undulator (IVU) with varying gap width is being developed for the new X-Ray source, PETRA IV at DESY. Its electromagnetic properties need to be investigated. These include, especially, the losses in the flexible taper transitions between the beam pipes and in the magnet array, as well as the impact of the IVU's impedance on beam stability. To assess the impedance of the structure, we employ numerical simulations. The challenges lie in the large size of the IVU, the wide frequency range due to the short bunch length, the highly resonant response of the system, and in the complex geometry of the structure. In a first step, wakefield simulations are carried out using CST Studio Suite. Subsequently, the shunt impedances are calculated by eigenmode simulations with the CST Studio Suite and a specialized in-house frequency domain impedance solver.
Paper: MOPM034
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM034
About: Received: 03 May 2023 — Revised: 05 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM036
Lifetime without Compromise
1068
Diffraction-limited light sources have garnered significant interest -- yet the smaller equilibrium size of their electron bunches also reduces the beam-lifetime. One remedy is to vertically excite the electron beam, for instance using a Multi Bunch Feedback (MBF) system. Previous work has demonstrated that this approach can safely increase the vertical emittance, thus beam-lifetime. However, not all operational vertical emittances are created equal. Driving the beam at frequencies near resonances can generate large coherent beam-centroid motion that results in an enlarged apparent photon-source. In this work, we present a methodology, justified with theoretical reasoning and simulation, that finds the optimal combination of frequency and kick strength that satisfies both the operational requirements and the beamline interests. The methodology is then demonstrated for the Diamond-II lattice, including short-range wake effects.
Paper: MOPM036
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM036
About: Received: 24 Apr 2023 — Revised: 11 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
MOPM037
Investigations into operating Pulse Picking by Resonant Excitation (PPRE) in the vertical plane
1071
As preparation for the upcoming Diamond-II upgrade, provisions for timing-users (those who predominantly care about the timing characteristics of the synchrotron radiation) are being investigated. Although ‘Hybrid bunch’ modes are currently employed at Diamond, such operation presents challenges for Diamond-II that merit investigating alternative approaches. PPRE, one such approach, involves resonantly exciting a targeted electron bunch using a Transverse Multi Bunch Feedback system (TMBF). We report on the efficacy of the TMBF for driving one (or few) bunches, focusing on studying the charge-dependent effects and the achieved vertical emittance, and also by considering the effect of long range impedance between bunches. Furthermore, to test experimentally the use of PPRE, we present our first results from a representative beamline. The work is also discussed in context of the proposed operational requirements for Diamond-II.
Paper: MOPM037
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM037
About: Received: 02 May 2023 — Revised: 11 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
MOPM038
Progress on the storage ring physics design of Hefei Advanced Light Facility (HALF)
1075
The Hefei Advanced Light Facility (HALF) is a soft X-ray and VUV diffraction-limited storage ring to be built in the Hefei city of China. This paper reports the recent progress on the physics design of the HALF storage ring, including lattice modification and optimization, error and insertion device effects, collective effects, injection scheme and collimation.
Paper: MOPM038
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM038
About: Received: 03 May 2023 — Revised: 16 Jun 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
MOPM039
On-resonance round beam experiment in the HLS-II storage ring
1079
The strong intra beam scattering effect and the increase in horizontal emittance become common issues for next-generation ultra-low emittance storage rings. The round beam can be an effective method to solve these problems. Moreover, the produced round synchrotron radiation is suitable for optical matching. The on-resonance tune is an easier method to achieve round beam. In this paper, simulation and experimental results are introduced based on the nominal lattice of the HLS-II storage ring.
Paper: MOPM039
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM039
About: Received: 01 Apr 2023 — Revised: 06 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
MOPM040
Beam transfer line of Wuhan Advanced Light Source
1082
Wuhan Advanced Light Source (WALS) is a fourth generation diffraction limit synchrotron radiation facility, which is composed of a full energy 1.5 GeV LINAC, a 1.5 GeV Storage Ring and 10 beamlines for its phase I project. The LINAC is 6 meters lower than the storage ring, which is connected by a 46 meters beam transfer line. The beam transfer line includes three parts, one ver-tical line between two horizontal lines. Four achromat sections are used, the first three are 30 degrees with exact same settings and the last one is matched with the storage ring injection septum and non-linear kicker. In this paper, the optic and error correction results are described in brief, especially the dispersion correction. Since there are horizontal and vertical dispersions at the same time, the correction process must correct both of them at the same time.
Paper: MOPM040
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM040
About: Received: 28 Apr 2023 — Revised: 06 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
Vacuum system for Wuhan Advanced Light Source storage ring
The main accelerator of WALS (Wuhan Advanced Light Source) is a 1.5 GeV, 180 m storage ring with emittance 222.8 pm.rad, which reaches soft X-Ray diffraction limit. To achieve such low emittance, the magnet system is designed very compact with very small aperture. And this results in a narrow transition structure and a low flow conductivity vacuum chamber. In consideration of the beam lifetime, the vacuum system requires the average static and dynamic pressures to be better than 5×10-10 Torr and 1×10-9 Torr, respectively. And the distributed pumping and proper absorption of synchrotron radiation load are required. In this paper, oxygen-free high-conductivity copper (OFHC) is used as the main material of storage ring vacuum chamber. And the radiation load in the storage ring was solved by providing water along the illuminate of synchrotron radiation surface and area. The Non-evaporation getter (NEG) coating provides a distributed pumping which can acquired by vacuum magnetron sputtering plating, significantly reduce the cost and complexity of storage ring vacuum system construction.
MOPM043
Microwave instability threshold from coherent wiggler radiation impedance in storage rings
1085
Numerical simulations of the beam dynamics with the Coherent Wiggle Radiation (CWR) impedance for the preliminary EIC back-up ring cooler parameters and positive and negative momentum compaction are discussed in detail. We show the microwave instability threshold dependence on low-frequency CWR impedance in free space and for parallel plates. The numerically simulated results performed by the Vlasov-Fokker Planck solver and the ELEGANT code have been compared with a new analytical approach to cross-check the microwave instability threshold.
Paper: MOPM043
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM043
About: Received: 03 May 2023 — Revised: 03 Jun 2023 — Accepted: 22 Jun 2023 — Issue date: 26 Sep 2023
MOPM044
Study on magnets sorting for the HEPS booster
1088
The High Energy Photon Source (HEPS) is a 1360.4-m, 6-GeV, ultralow-emittance light source, being built in the suburb of Beijing, China. The HEPS booster contains 128 dipoles,148 quadrupoles and 68 sextupoles, which are divided into several groups. The magnets in one group are connected in series, and powered by a single power supply. To minimize the impact on beam dynamics, magnets sorting needs to be done. The RMS values of closed-orbit distortion and beta-beating were used as the merit functions of dipole sorting and quadrupole sorting, respectively, and the sextupoles were grouped with the integral field differences between magnets. This paper will present the sorting process and the results of beam dynamics after sorting.
Paper: MOPM044
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM044
About: Received: 27 Apr 2023 — Revised: 07 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM045
Development of single mode cavity at 1.5 GHz for the third harmonic RF-system in PETRA IV
1091
The PETRA IV storage ring currently under development at DESY will require a third harmonic 1.5 GHz RF-system to prevent negative effects on both, lifetime and emittance, caused by Touschek effect and Intrabeam scattering. These cavities lengthen the bunches and thereby reduce their charge density. For this 3rd harmonic system, a one-cell single-mode cavity with a simple mechanical and electrical structure is under design that should also reduce Higher Order Modes (HOMs) to a quality factor less than 100. Therefore, the well-known approach of the Choke Mode Cavity was chosen, that use a radial line damper to attenuate the HOMs and a radial choke that traps the acceleration mode. The general behaviour of the choke mode structure was simulated, discussed and optimized for the requirements of a one-cell cavity with high effective shunt impedance, high-quality factor and simple manufacturing.
Paper: MOPM045
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM045
About: Received: 28 Apr 2023 — Revised: 16 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
MOPM046
Ion effects studies for Diamond-II with a simplified model
1095
Ion instabilities are a major concern in diffraction-limited storage rings. ELEGANT offers a `strong-strong' model for ion simulations that describes both the beam and ions using multi-particles. To balance accuracy and computing resources, a simplified model using ILMATRIX and one IONEFFECTS element per turn is employed to study the ion effects of the Diamond-II storage ring. After benchmarking, it was found that the simplified model overestimates the ion instability compared with element-by-element tracking by a small amount. A preliminary vacuum conditioning process has been studied, and ion instabilities have been analysed at different stages for various filling patterns. This paper outlines the simulation settings and presents preliminary results, including the filling patterns to be used at each stage of vacuum conditioning. The ion instability for hybrid filling patterns at the expected operational vacuum condition is also studied.
Paper: MOPM046
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM046
About: Received: 02 May 2023 — Revised: 07 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
MOPM047
RF feedback simulation for Diamond-II using ELEGANT
1099
The Diamond-II storage ring will utilise normal conducting main cavities and a passive superconducting harmonic cavity in its RF system. To evaluate the effects of bunch lengthening and lifetime gain from the harmonic cavity for different filling patterns, transient beam loading effects need to be studied. When simulating these effects with ELEGANT, RF feedback for the main cavities must be defined using sets of infinite impulse response (IIR) filters. This paper describes the method used to convert proportional-integral (PI) feedback parameters representative of the RF feedback implemented at Diamond into equivalent ELEGANT settings and presents simulation results demonstrating the effectiveness of the RF feedback. Transient beam loading effects for the standard and hybrid filling pattern are also studied.
Paper: MOPM047
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM047
About: Received: 02 May 2023 — Revised: 08 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
MOPM049
Studies on beam instabilities in the storage ring of SAPS
1103
The South Advanced Photon Source (SAPS) is a newly proposed storage ring (SR) based photon source project operating at the beam energy of 3.5GeV. To achieve X-ray diffraction-limited in the SR with high density bunch, larger coupling impedance brought by more compact beam pipe structure is inevitable, which makes the beam collective effects be one of the major challenges to the physical design. By impedance modelling and beam dynamics simulations, the longitudinal and transverse beam instabilities in SR have been studied.
Paper: MOPM049
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM049
About: Received: 03 May 2023 — Revised: 12 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
MOPM050
Study on transverse multi-bunch instability in Elettra 2.0
1106
One of the main characteristics of the future light sources like Elettra 2.0 is the small vacuum chamber cross section. In fact, the resistive-wall (RW) impedance due to the small vacuum chambers cross section enhances transverse coupled-bunch instabilities. In this study, the effect of the RW in the multi-bunch case is investigated versus chromaticity. The threshold currents in the presence of broad-band and RW impedances are estimated for the Elettra 2.0 storage ring at different values of chromaticity using macroparticle tracking and frequency domain semi-analytical calculations. In particular, it is found that, above a certain chromaticity, the threshold current is determined by the radial head-tail modes. In view of mitigating these instabilities, the effectiveness of the transverse bunch-by-bunch feedback system as well as bunch-lengthening harmonic cavities is also useful.
Paper: MOPM050
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM050
About: Received: 02 May 2023 — Revised: 11 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
MOPM051
Broad band impedance effects on Elettra 2.0
1110
Due to the reduced diameters of the vacuum chambers and of the other equipment, the performance of the next generation light sources can be greatly affected resulting in a reduction of the intensity in both single and multi-bunch operations. This is particularly important for Elettra 2.0 since there are plans to incorporate bunch compression schemes for providing very short photon pulses. In this study, the resistive wall and single bunch instabilities are investigated by tracking in order to define their thresholds.
Paper: MOPM051
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM051
About: Received: 23 Apr 2023 — Revised: 11 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
MOPM052
Elettra 2.0 - the girder support design
1113
Elettra will be upgraded between 2025 and 2026 and the storage ring lattice will be totally different to enhance the emittance and improve the coherence of the machine. The storage ring design requires a stiff support system to reduce the impact of vibrations on the electron orbits, a high thermal stability as well as low static deformations. The magnets support system must be easy to transport, align and must be cost effective. In order to achieve these requirements, the magnets supports of each synchrotron cell are granite blocks long from 0.8 to 1.57 m and the girder alignment system consists of 3 main adjustment feet and 2 stiffeners. An optimization study was conducted de-fining the most effective location of the feet. Each magnet can be aligned on the girder by means of 3 levelling wedges that can be moved both manually and automatically by means of motorized actuators. A FEA calculation was carried out to optimize the design in order to achieve a target stiffness and an experimental test was performed on a prototype girder in order to verify the numerical results.
Paper: MOPM052
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM052
About: Received: 10 May 2023 — Revised: 08 Jun 2023 — Accepted: 08 Jun 2023 — Issue date: 26 Sep 2023
MOPM053
Bending magnet photon absorber design and calculations for Elettra 2.0 storage ring
1117
To harness the major advances that have been done in the field of synchrotron light research, Elettra synchrotron radiation facility is being updated. Presently in its design phase, the Elettra 2.0 project will allow new and better research to be performed at the facility. In the upgrade of the storage ring, the new 6BA lattice brings challenges in terms of available space and radiated power. This paper presents the bending magnet photon absorber designed to cope with the new requirements. The absorber concept created for ESRF-EBS has been revised and re-engineered to make it suitable for the specific features of Elettra’s sources. To reduce the high-power densities induced by the short source-absorber distance, the one-jawed, toothed profile was obtained via a robust optimization, considering possible misalignments or beam miss-steering. Novelty of the approach is the absorber insertion in the vacuum chamber from the inside of the ring. Finally, presented are the thermo-mechanical and computational fluid dynamics simulations (ANSYS) performed to validate the design, comprehensive of a *monte-carlo*, *ray-traced* simulation to evaluate photon reflections (SYNRAD) and their effects.
Paper: MOPM053
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM053
About: Received: 03 May 2023 — Revised: 08 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
MOPM058
Status and progress of the RF system for high energy photon source
1121
High Energy Photon Source (HEPS), a 6 GeV diffraction-limited synchrotron light source, is currently under construction in Beijing. The double-frequency RF system is being developed to deliver 6 MV of RF voltage and 850 kW of beam power with an active third harmonic system. The prototypes of the higher-order-mode damped 166.6 MHz quarter-wave superconducting cavities, as well as the 499.8 MHz harmonic superconducting cavities, have been manufactured and vertical tested, while the cryomodules for these cavities are being developed. All six normal-conducting 5-cell cavities were high-power tested and three of them have been installed in the booster tunnel for initial beam commissioning. Following the success of the prototype 166.6 MHz 260 kW and 499.8 MHz 150 kW solid-state power amplifiers, the series production of the amplifiers is underway. The new low-level RF control system based on Xilinx FPGA is in the prototyping phase and the first lab test results fulfill the HEPS requirements. This paper presents the status and progress of the RF system for HEPS.
Paper: MOPM058
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM058
About: Received: 27 Apr 2023 — Revised: 08 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
MOPM059
Magnetic measurement of the magnets with trim coils in the HEPS storage ring
1125
The High Energy Photon Source (HEPS) is a 34-pm, 1360-m storage ring light source being built in the suburb of Beijing, China. In the HEPS storage ring, a proportion of quadrupoles and sextupoles are equipped with trim coils for horizontal and vertical orbit correction. For these magnets, the main field and corrector fields may have non-ignorable impact on each other. We have carried out detailed measurements and subsequent data analysis of these magnets. It is observed that changing the corrector currents in the presence of constant main current, can lead to a relative deviation of the main field of 0.1 percent level. In this paper, we will report the measurement procedure and main results.
Paper: MOPM059
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM059
About: Received: 02 May 2023 — Revised: 19 Jun 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
MOPM060
Study of the ramping process for Korea-4GSR
1128
The Korea fourth generation storage ring (Korea-4GSR) is a 4GeV, low emittance light source to be built in Ochang, Korea. The booster ring, which consists of 26 FODO standard cells and 2 dispersion-free cells, ramps the beam energy up from 200 MeV to 4 GeV as part of the injector. The circumference and repetition rate of the booster ring is 772.9 m and 2 Hz, respectively. In this paper, the injection scheme, energy ramping curve, eddy current effect, beam parameters changing curve, and RF voltage during the energy ramping in the booster ring will be presented in detail.
Paper: MOPM060
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM060
About: Received: 28 Apr 2023 — Revised: 05 Jun 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
MOPM061
Sextupole injection at TPS
1131
The feasibility of performing sextupole injection at TPS (Taiwan Photon Source) storage ring has been demonstrated in November 2021 with 300 mA stored electron beam. In order to carry out the experiment, a sextupole and its associated pulser were fabricated according to the specifications required. The sextupole was installed during a short break in September 2021 by making use of a ceramic unit located between kicker-3 and kicker-4 at the injection straight section. Moderate adjustment of the beam injection trajectory at the BTS (booster-to-storage ring) transfer line is needed so as to avoid beam scraping off at the injection septum. A brief description of the preparation work is given and the experimental results are summarized in this report.
Paper: MOPM061
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM061
About: Received: 25 Mar 2023 — Revised: 08 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
MOPM065
Generalized longitudinal strong focusing in a storage ring for coherent EUV radiation
1134
A laser-driven storage ring is proposed to generate steady-state, nanometer-long electron bunches. A ring of this type can produce coherent EUV radiation with greatly enhanced power and photon flux, benefiting a wide range of scientific and industrial communities, including condensed matter physics and computer chip fabrication. The underlying mechanism is called generalized longitudinal strong focusing (GLSF), which invokes precise transverse-longitudinal coupling dynamics and lowers the required laser power significantly by exploiting the ultrasmall vertical beam emittance. A practical instance indicates that kW-level coherent EUV radiation is attainable in a GLSF ring with a modulation laser power as low as 1 MW, allowing for continuous-wave operation of up-to-date optical cavities.
Paper: MOPM065
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM065
About: Received: 03 May 2023 — Revised: 25 May 2023 — Accepted: 25 May 2023 — Issue date: 26 Sep 2023
MOPM067
Commissioning of the RF system for the ThomX storage ring
1137
The RF system of the ThomX storage ring consists in a 500 MHz single cell copper cavity of the ELETTRA type, powered with a 50 kW CW solid state amplifier, and its associated Low-Level RF feedback and control loops. The low operating energy of 50 MeV makes the impedances of the cavity higher order modes (HOMs) particularly critical for the beam stability. Their parasitic effects on the beam can be cured by HOM frequency shifting techniques, based on a fine temperature tuning and a dedicated adjustable plunger. A cavity temperature stability of ± 0.1 °C within a range from 30 up to 70 °C is achieved by a precise control of its water-cooling temperature. On the other hand, the tuning of the cavity fundamental mode is achieved by changing its axial length by means of a mechanical tuner. This report describes the setup of the facility and the results of the commissioning.
Paper: MOPM067
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM067
About: Received: 31 Mar 2023 — Revised: 08 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM069
Commissioning of the ThomX Storage Ring
1141
We will report on the ongoing ThomX ring commissioning, its status, its main challenges, our results and our planning. ThomX is a compact Compton-based X-ray source under commissioning at IJCLab in Orsay (France). This facility is composed of a 50-70 MeV linac, a transfer line and a storage ring whose closed orbit is 18 m long. Compton scattering between the 50 MeV electron bunch of 1 nC and the 30 mJ laser pulses stacked in a Fabry-Perot cavity results in the production of X-rays with energy ranging between 45 keV and 90 keV. We aim at a total flux of about 10^13 X-rays per second. The injector commissioning started in the spring of 2021. The ongoing storage ring commissioning faces many challenges due to the ring’s low energy, its compactness, its non-linear beam dynamics, the time-limited beam storage and the need to achieve a very accurate and stable geometry of the collision region between the laser pulses and the electron bunch. The commissioning and operational experience is of great importance for the future Compton sources.
Paper: MOPM069
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM069
About: Received: 08 May 2023 — Revised: 22 May 2023 — Accepted: 22 May 2023 — Issue date: 26 Sep 2023
MOPM071
Slow extraction with octupoles at CERN proton synchrotron to improve extraction efficiency
1144
The extraction inefficiency of the slow extraction process induces radioactivity in the area surrounding the electrostatic septum. Studies at the CERN Proton Synchrotron (PS) are investigating beam loss reduction techniques to improve the efficiency of the beams provided to the experiments of the East Area. Powering octupoles distorts the transverse phase-space of the extracted beam which can be exploited to maximize the number of particles in the field region of the septum with respect to the number lost on the septum. The effect of octupoles on the separatrices near the third-order resonance is simulated with MADX-PTC tools to observe phase space folding and to predict the multipole parameters needed to minimize beam loss. Experimental studies are performed to confirm the validity of the simulation models and to quantify the net benefit of using octupoles to improve the extraction efficiency.
Paper: MOPM071
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM071
About: Received: 04 May 2023 — Revised: 07 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
MOPM072
Dynamics of off-axis injection near the coupling resonance at PETRA IV
1148
The PETRA IV project will have a storage ring with an ultra-low natural emittance of 20 pm rad [1]. For an off-axis injection scheme with working points at the difference resonance it is important to assure the vertical excursion arising due to transversal coupling such, that injection efficiency is not compromised. In this contribution we present simulations results of an off-axis injection near the coupling resonance, which provides equal equilibrium emittances. Advantages and disadvantages of such a scheme are discussed.
Paper: MOPM072
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM072
About: Received: 08 May 2023 — Revised: 09 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
MOPM073
Study of aperture sharing injection scheme for Diamond-II
1152
The Diamond-II storage ring has been designed to increase photon brightness by up to two orders of magnitude compared to the existing Diamond facility. A single-bunch aperture sharing injection scheme using short stripline kickers applied with high-voltage nano-second pulsers was proposed to provide both high injection efficiency and high photon beam stability in top-up mode [1]. The quasi-transparent injection process has been optimised and studied using Accelerator Toolbox. The results of these study will be presented.
Paper: MOPM073
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM073
About: Received: 28 Apr 2023 — Revised: 10 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM075
Beam-based characterization of a non-linear injection kicker at BESSY II
1156
Top-up operation at BESSY II is performed with average injection efficiencies of 98 %. However, the four-kicker bump and the septum, that form the present injection system, both contribute to a distortion of the stored beam with an amplitude of about two millimeters for several thousand turns after injection. A non-linear injection kicker (NLK) could be used to reduce the distortion due to the kicker bump by a factor of approximately 30 - a necessary condition for transparent injection. Studies with an NLK and optimized sextupole settings have shown that it is also possible to achieve injection efficiencies of up to 97 %. The NLK was characterized beam-based with regards to the application of the NLK for BESSY II user operation, a possible injection method for BESSY III and to get a better understanding of the limiting effects of the injection efficiency. Additionally, measurements and simulations were compared.
Paper: MOPM075
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM075
About: Received: 03 May 2023 — Revised: 07 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM078
Longitudinal injection for SAPS based on a double-frequency RF system
1159
In the fourth-generation storage ring light sources, the dynamic acceptance is usually small related to the extremely strong nonlinearity inherent in the multi-bend achromat design, making it difficult to implement traditional off-axis local-bump injection. It was found that a double-frequency rf system can be used for longitudinal injection with the help of rf gymnastics. However, such schemes require tuning the RF parameters during injection, which would challenge the RF hardware system and cause the bunch length shrinking of the circulated bunch. In this paper, we find that with proper parameters optimization, a double-frequency RF system with static parameters can be used for longitudinal injection. A detailed design of this scheme for the application in the Southern Advanced Photon Source (SAPS) is presented.
Paper: MOPM078
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM078
About: Received: 24 Apr 2023 — Revised: 10 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
MOPM081
Degrader beamline design at the CEBAF injector for machine acceptance studies
1162
A degrader device is being built at the CEBAF injector to degrade the electron beam phase space for machine acceptance studies. The electron beam is degraded through multiple scattering in a thin target before further transport in the injector beamline for injection into CEBAF. The degraded electron beam will approximate phase space distributions expected from a bremsstrahlung-based polarized positron source as in the PEPPo method. The effort is in broader support of the Ce+BAF positron capability that is currently under study. Two options for the degrader device are considered, and simulation results are presented.
Paper: MOPM081
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM081
About: Received: 02 May 2023 — Revised: 14 Jun 2023 — Accepted: 22 May 2023 — Issue date: 26 Sep 2023
MOPM082
Preliminary electron injector design for a steady-state microbunching light source
1166
The Steady-State Microbunching (SSMB) mechanism, which combines the benefits of high repetition rate of a storage ring and coherent radiation, has the potential to produce high average power short wavelength light. In order to generate kilowatt level radiation, the electron injector should have the ability to provide a 1 A average current, 100 ns long DC beam, with the requirements of small emittance (<1~mm$\cdot$ mrad), and very small energy spread (<$5\times 10^{-4}$) for the SSMB storage ring. This paper presents an overview of the physical design of the electron gun, linac, and stretching ring components of the injector, as well as the beam loading compensation methods employed in the electron gun and linear accelerator.
Paper: MOPM082
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM082
About: Received: 03 May 2023 — Revised: 24 May 2023 — Accepted: 24 May 2023 — Issue date: 26 Sep 2023
MOPM083
Beam injection with an anti-septum into the HALF storage ring
1170
Compared to the conventional injection scheme, the three-kicker bump injection scheme with an anti-septum has two advantages. One is less requirement of dynamic aperture thanks to the thin blade of the anti-septum, the other is less installation space requirement of the injec-tion system. Both are beneficial to the beam injection for the fourth generation light sources. In this study, the application of this injection scheme to the HALF storage ring is presented. The layout and parameters of the injec-tion system are designed and the injection process is simulated. The results of the injection efficiency and the effect on the stored beam during beam injection is shown in this paper.
Paper: MOPM083
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM083
About: Received: 03 May 2023 — Revised: 11 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
MOPM085
Beam injection using a nonlinear kicker for the HLS-II storage ring
1173
The single nonlinear kicker (NLK) injection has been adopted by several synchrotron radiation light source facil- ities or their upgrades. The injected beam receives a kick from an NLK and goes into the acceptance of the storage ring while the stored beam passes through the center of the NLK where the magnetic field is almost zero. Compared with the local-bump injection, NLK injection requires less space for kickers and causes less oscillation amplitude for the stored beam during injection. Currently, a conventional local bump injection including four pulsed dipole kicker magnets is adopted in the HLS-II storage ring. In this paper, we propose an NLK injection scheme by only replacing one kicker with a pulsed NLK for HLS-II. The simulation result is also presented.
Paper: MOPM085
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM085
About: Received: 03 Apr 2023 — Revised: 11 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
MOPM086
Studies on beam injection system for Wuhan Advanced Light Source storage ring
1176
Wuhan Advanced Light Source (WALS) is the low-energy 4th generation advanced light source, which is proposed by Wuhan, China. WALS includes a 1.5 GeV full-energy LINAC injector, a 180 m circumference, 1.5 GeV low-emittance storage ring, and a series of start-of-the-art beam lines. The standard 7BA magnetic focusing structure is adopted for the storage ring to lower the beam natural emittance and the lattice has been well- designed and optimized by multiple-objective genetic algorithm to maximize the dynamic aperture and energy acceptance. The dynamic aperture of the storage ring at injection can reach up to 8 mm in the horizontal plane, which makes the off-axis beam injection method possible. An off-axis beam injection scheme based on the pulsed nonlinear magnet is to be employed for the storage ring. Detailed studies about the beam injection scheme, including the beam optical design, nonlinear magnet design and optimization, have been performed and multi-particle simulations have also been carried out to study the beam injection procedure, which will be presented in this paper.
Paper: MOPM086
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM086
About: Received: 27 Apr 2023 — Revised: 09 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
MOPM087
Permanent helical undulators with strong fields
1180
Undulators containing magnetized rare-earth helices can provide a significantly higher oscillatory electron velocity than the widely used planar Halbach undulators. Using Wire Electrical Discharge Machining (WEDM) and combining planar tool with rotary work piece motion, it is possible to manufacture NdFeB helices with a period of 1 mm or less with high accuracy. In this work, we describe the results of manufacturing, theoretical and experimental studying prototypes of micro-undulators in the form of one or two longitudinally magnetized helices. Also shown are more efficient hybrid systems of two longitudinally oppositely magnetized and two steel pre-non-magnetized helices with a field on the axis of the order of 1 T. Such micro-undulators can significantly increase the efficiency of X-ray Free Electron Lasers and Inverse Free Electron Lasers.
Paper: MOPM087
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM087
About: Received: 10 May 2023 — Revised: 11 May 2023 — Accepted: 22 Jun 2023 — Issue date: 26 Sep 2023
MOPM088
Study of insertion devices effects in SIRIUS
1184
SIRIUS is the 4th generation synchrotron light source built and operated by the Brazilian Synchrotron Light Laboratory (LNLS). SIRIUS is currently operating with six beamlines and eight others are at different stages of deployment. In this work we report on the development of simulation tools to analyze the impact of insertion devices (IDs) on SIRIUS beam orbit, optics and dynamic aperture (DA), aiming at defining their specifications for external suppliers and verifying the feasibility of installing existing IDs. In particular, we analyze the fields of two IDS used in the previous LNLS synchrotron light source (UVX), now decommissioned: one planar 2T hybrid wiggler and one EPU of the type Apple-II. These IDs were installed in SIRIUS in 2022 and are now temporarily serving as light sources for the commissioning of PAINEIRA and SABIÁ beamlines. Furthermore, we also analyze the effects of two new IDs that will be used as titular light sources for CARNAÚBA, CATERETÊ, EMA, and PAINEIRA beamlines. One is an In-Vaccum Undulator (IVU) and the other is a Vertically Polarizing Undulator (VPU). An undulator built In-house will be used as a temporary light source for the SAPUCAIA beamline commissioning and its effects on SIRIUS beam parameters are also reported.
Paper: MOPM088
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM088
About: Received: 03 May 2023 — Revised: 22 May 2023 — Accepted: 22 Jun 2023 — Issue date: 26 Sep 2023
MOPM091
Magnetic Measurement of Tapered Gap U50 Undulator
1188
The Tapered undulator provides interesting possibilities for keeping the undulator in resonance with the electron beam along the length of the undulator. The U50-II [1,2] undulator at Laser and Insertion Device Application Laboratory of DAVV, India is a 1000mm length, 50mm period length undulator. The four heavy-duty precise lead screw attached to the mechanical girder allows its gap to be tapered. In this paper, we report the field integral, phase error measurement of the tapered U50-II PPM undulator by Hall probe method and compare its accuracy by stretched wire result [3].
Paper: MOPM091
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM091
About: Received: 09 Apr 2023 — Revised: 05 Jul 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
MOPM093
Quasi-periodic Apple-knot undulator for Diamond Light Source
1192
The user community of the Angle-Resolved Photoemission Spectroscopy (ARPES) beamline in Diamond Light Source (DLS) is strongly interested to use the lower photon energies down to 10 eV compared to the current 18 eV in both Diamond and the future 3.5 GeV machine Diamond-II. The high level of the heat load on the first optic as well as the undesired higher harmonics contamination are two major challenges for the beamline operation. The Quasi-Periodic APPLE-KNOT (QP-AK) undulator is a potential candidate to resolve these two issues. This paper presents the magnetic design and reports the overall performance of the undulator in terms of flux, polarisation degree and partial power. The linear and non-linear beam dynamics effects of the undulator are investigated by the kick-map approach. Active shims will be used to suppress the dynamic multipoles of the device, as used with the current APPLE-II device. The beam dynamics studies show the minimal impact on beam lifetime and injection efficiency and residual beta-beat in Diamond and its upgrade.
Paper: MOPM093
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM093
About: Received: 24 Apr 2023 — Revised: 05 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM095
An in-vacuum measurement system for CPMUs at Diamond Light Source
1196
An in-vacuum Hall probe measurement bench was designed, built, and used to measure four Cryogenic Permanent Magnet Undulators (CPMUs) at 77 K at Diamond Light Source. The devices were tuned to correct the phase error at cold temperatures based on the measurements from the in-vacuum bench. The in-vacuum bench consists of a stretched wire system supplied by Danfysik and the in-house Hall probe bench. The Hall probe bench has gone through two iterations: the first was prone to deforming with temperature changes; the second was made thicker following design changes to the magnet holders and girders of the CPMUs which allowed more space for the bench inside the vacuum vessel. The design and commissioning of the bench will be presented, along with some measurements of the CPMUs at room temperature and at 77 K. Details such as height compensation, temperature compensation, and triggering of the Hall probe measurements will be covered.
Paper: MOPM095
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM095
About: Received: 02 May 2023 — Revised: 09 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM096
CPMU development at diamond light source
1200
Over the last three years (2020-2022) Diamond Light Source has installed four in-house designed, built, and measured Cryogenic Permanent Magnet Undulators (CPMUs). All four are 2 m long with a 17.6 mm period and have a minimum operating gap of 4 mm. These have replaced existing 2 m long in-vacuum pure permanent magnet (PPM) devices to improve the flux to several of Diamond’s MX (Macromolecular Crystallography) beamlines by a factor of 2-4. In this paper we present the mechanical and cryogenic design considerations, and the shimming procedures and tools developed to produce these devices. The performance of the CPMUs compared to their PPM counterparts will also be reviewed.
Paper: MOPM096
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM096
About: Received: 31 Mar 2023 — Revised: 12 Jun 2023 — Accepted: 12 Jun 2023 — Issue date: 26 Sep 2023
MOPM097
Insertion device developments for Elettra 2.0
1204
The layout of Elettra 2.0 preserves the useful length of the long straight sections so that all the existing insertion devices (IDs) could in principle be maintained in the upgraded machine. However, new high-performance beamlines are planned that will take advantage of the much lower electron beam emittance. Therefore new undulators are being designed and constructed for these beamlines. Space is also available in some of the short straight sections, and we’re developing compact undulators and wigglers to make optimal use of them. In this contribution the parameters and characteristics of the new IDs will be presented.
Paper: MOPM097
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM097
About: Received: 27 Apr 2023 — Revised: 05 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM099
Effect of SCU long range errors on the FEL performance
1207
The FEL performance strongly correlates with the undulator field quality. The definition of mechanical tolerances for the undulator magnets allows us to achieve the wished field quality. These mechanical tolerances should be defined both on short and long-range errors. With long-range errors, we address problems like deformations of the yoke caused by the support structures or unwanted tapering, which can arise in the positioning procedure of the parallel undulator coils. In this contribution, we quantify the effect and set tolerances of a few types of long-range errors on the FEL radiation generated specifically from superconducting undulator coils.
Paper: MOPM099
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM099
About: Received: 02 May 2023 — Revised: 05 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM100
Magnetic field errors and possible correction schemes in SCUs
1211
One of the design challenges of Superconducting undulators (SCUs) is the fulfilment of tight mechanical tolerances. Simulations show that to guarantee high quality of the emitted radiation local mechanical errors must be below a few tens of micrometres. Such requirements are at the limit of the most precise machines and techniques for mechanical manufacturing. In addition, once the SCU is assembled with the support structure, mechanical deformations can affect the device in the long range. In this contribution, we describe the possible long and short-range errors that can arise in the SCU and we present various schemes based on shimming coils to correct the short-range errors.
Paper: MOPM100
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM100
About: Received: 02 May 2023 — Revised: 05 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM101
Status update on SUNADAE2 magnetic field test facility at European XFEL
1215
The implementation and further improvements of superconducting undulators is part of the European XFEL facility development program. Within this program, a magnetic field test facility is being developed. Named SUNDAE2 (Superconducting UNDulAtor Experiment 2), it aims to perform in-vacuum magnetic field measurements of superconducting undulators (SCUs) with three techniques: Hall probe, moving wire, and pulsed wire. This contribution presents the updates and status of SUNDAE2.
Paper: MOPM101
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM101
About: Received: 31 Mar 2023 — Revised: 28 May 2023 — Accepted: 22 Jun 2023 — Issue date: 26 Sep 2023
MOPM103
Undulators for BESSY III
1219
HZB is in the process of developing a concept for a successor to the BESSY II synchrotron facility. The new facility will build on the strengths developed in Berlin over the last twenty years in delivering flexibly polarised soft X-Rays to dozens of beamlines. The successor facility BESSY III is planned to operate at 2.5GeV, in comparison to the 1.7GeV operation of BESSY II. This makes it easier to achieve the goal of delivering 1keV photons to beamlines on the first harmonic of our APPLE II Insertion Devices. It also makes it easier to achieve the aspiration of delivering tender X-Rays up to 10keV more routinely to users utilising in-vacuum APPLE II devices*, Cryogenic Permanent Magnet Undulators (CPMUs) or Cryogenic APPLE devices[2]. However, it also presents challenges in delivering the low energy photons below 10 eV, as period lengths of the relevant undulators must be increased, which in turn increases on-axis power. APPLE-KNOT designs will be pursued to overcome this issue. The undulator group will also be planning Double Period Undulators[3] to offer beamlines broad spectrum coverage from 50eV to 10keV on the 1st and 3rd harmonics. This paper outlines the first choices of undulators to be available to the successor facility BESSY III.
Paper: MOPM103
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM103
About: Received: 03 May 2023 — Revised: 11 May 2023 — Accepted: 22 Jun 2023 — Issue date: 26 Sep 2023
MOPM105
UNDUMAG - WAVE recent developments
1223
The codes UNDUMAG and WAVE have been developed at HZB/BESSY. They are used intensively to design undulators, and to understand their magnetic and synchrotron radiation properties, as well as their impact on the storage ring. Recent extensions will be presented. A more intuitive input file to define undulator geometry has been developed, as well as a Python based GUI that allows the set-up of common undulator types. This GUI also allows the visualization of results. The magnetization of permanent magnet blocks can now be defined in terms of polynomial coefficients to simulate and study magnet inhomogeneities. WAVE has also been interfaced to UNDUMAG to calculate the real magnetic field of insertion devices. A second undulator mode has also been developed that calculates undulator synchrotron radiation by summing the radiation field amplitudes of a single period with appropriate phase advance and depth of field effect corrections. Field and phase errors can be included in this mode, which has seen a speed performance increase of an order of magnitude.
Paper: MOPM105
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM105
About: Received: 03 May 2023 — Revised: 25 May 2023 — Accepted: 25 May 2023 — Issue date: 26 Sep 2023
Techniques for fabrication of crystalline undulators as an innovative intense source of 𝛾-rays
High-intensity, monochromatic X and 𝛾-rays are a powerful tool for applied science in all fields. Free-Electrons Lasers can generate soft X-rays. A magnetic undulator's shortest possible oscillation period is ~1 cm, which restricts the photon energy to hundreds of keV at GeV-range electron energies. Inverse Compton Scattering, which needs powerful lasers, may provide hard X-rays and 𝛾-rays. An interesting alternative is crystalline undulators (CU), i.e., a periodically bent crystal in which channeled charged particles follow the bending of the crystalline planes, thus generating e.m. radiation in analogy with standard magnetic undulators. The oscillation period can be lowered to sub-millimetric size, resulting in tens of MeV in photon energy using GeV electron beams[1]. A CU has the great advantage of being a passive and highly sustainable element, requiring neither magnets nor intense lasers. Different techniques for producing CU, by taking advantage of modern technologies, will be illustrated. The grooving method[2], low-pressure chemical vapor deposition[3], ion implantation, and pulsed laser melting can provide a periodic deformation field that leads to a periodic bending of the crystal structure. References: [1] Novel Light Sources Beyond Free Electron Lasers, A.Korol; A.V. Solov’yov, Springer Cham, (2022) [2] R. Camattari et al., Phys. Rev. Accel. Beams 22 (2019) 044701 [3] L. Lanzoni et al., International Journal of Engineering Science 46 (2008) 917
MOPM108
A THz superconducting undulator for flute - Design parameters and layout
1226
The far-infrared linac and test experiment (FLUTE) serves as an accelerator test facility for a variety of accelerator physics studies. FLUTE is foreseen to provide coherent radiation in ultra-short, very intense light pulses in the terahertz (THz) and far-infrared spectral range. A superconducting undulator in the accelerator structure after bunch compression offers the possibility to generate high-energy, pulsed radiation between 4 THz and 12 THz corresponding to photon energies between 16.5 meV and 50 meV. This energy range, for instance, is of high interest for interaction and reaction studies of liquids, especially in water, and thus for materials and medical research. In this contribution we describe the specific design parameters and the general layout of the THz superconducting undulator to reach the envisioned scientific goals.
Paper: MOPM108
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM108
About: Received: 05 May 2023 — Revised: 08 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
MOPM109
Development of an elliptically polarizing X-type undulator for fourth generation light sources
1230
The Advanced Light Source (ALS) at the Lawrence Berkeley National Laboratory (LBL) is going through an upgrade (ALS-U), where the ALS triple-bend achromat is replaced by a nine-bend achromat storage ring (SR) with on-axis injection using beam swapping from a triple-bend achromat accumulator ring (AR). The small beam size at the straight sections of the ALS-U has opened the possibility to use small-diameter circular vacuum chambers for insertion devices. An elliptically polarizing X-type undulator with a small circular vacuum chamber and symmetric placement of the magnet rows around the vacuum chambers is being developed at LBL. This type of undulator is suitable for the ALS-U and other fourth generation light sources. Salient features of the X-type undulator include the mechanical construction with compact crossed roller bearings and fully hydraulic motion control system. These are described together with a status report of the progress of the prototyping work.
Paper: MOPM109
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM109
About: Received: 03 May 2023 — Revised: 05 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM110
Progress and challenges of the compact APPLE X undulator prototype at MAX IV
1233
The potential future Soft X-ray (SXL) FEL beamline at the linear accelerator at MAX IV will require a series of undulators with distinct properties: It must be cost-effective and compact. Furthermore, it needs to have a small and round magnetic gap and provide elliptically polarized light under full polarization control. This undulator of a compact APPLE X type is currently being prototyped in the Insertion Device group at the MAX IV Laboratory. In this paper, we present the technical requirements of both, the mechanical and magnetic challenges that follow with the compactness and complexity of the device. Thereafter, we outline the assembly procedure of the undulator and present the methods we intent to use for magnetic measurements to evaluate the prototype's performance.
Paper: MOPM110
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM110
About: Received: 02 May 2023 — Revised: 08 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM111
Pulsed wire magnetic field measurements for an in-vacuum undulator
1236
An in-vacuum undulator is important for synchrotron radiation. An in-vacuum undulator with a permanent-magnet is used by the Taiwan Photon Source (TPS) in the National Synchrotron Radiation Research Center (NSRRC). Before installation in the storage ring, the magnetic field of the undulator is measured at the oper-ational gaps. The magnetic-field for an in-vacuum un-dulator is measured using a Hall-probe and a stretched-wire measurement system. This study uses a pulsed wire magnetic field measurement system for an in-vacuum undulator. A reference magnet with a known magnetic field is used to determine the magnetic field profile for an in-vacuum undulator and it is demonstrat-ed that the oil dampers crucial to eliminating dispersion waves for the pulsed wire measurement. The results are used to compare the magnetic field measurements that use a pulsed wire with those that use a Hall probe.
Paper: MOPM111
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM111
About: Received: 27 Apr 2023 — Revised: 07 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPM112
Strongly tapered helical undulator system for FAST-GREENS installation
1240
RadiaBeam, in collaboration with UCLA and Fermilab, is developing a strongly tapered helical undulator system for the Tapering Enhanced Stimulated Superradiant Amplification experiment at 515 nm (TESSA-515). The experiment will be carried out at the FAST facility at Fermilab as a Gamma-Ray high Efficiency ENhanced Source (FAST-GREENS). The undulator system was designed by UCLA, engineered by RadiaBeam, and will be installed on the beamline at Fermilab. The design is based on a permanent magnet Halbach scheme of four 1-meter long undulator sections; two of which have been completed and installed. The undulator period is fixed at 32 mm and the magnetic field amplitude can be tapered by tuning the gap along the interaction. Each magnet can be individually adjusted by 1 mm, offering up to 25% magnetic field tunability with a minimum gap of 5.58 mm. This paper discusses the design and engineering of the undulator system and the stage 0 installation status.
Paper: MOPM112
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM112
About: Received: 08 May 2023 — Revised: 10 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
MOPM113
First test results of a short period superconducting helical undulator
1243
Superconducting undulators provide a possible means of broadening the range of wavelengths that can be covered by an XFEL facility by generating larger magnetic fields at shorter periods than can be achieved using permanent magnet undulators. As part of ongoing prototyping work at STFC to develop a superconducting helical undulator with 13 mm period and 5 mm magnetic gap, a test cryostat has been designed and built to investigate the performance of 325 mm long prototype magnets. The test cryostat is used to cool prototypes to 4.2 K and to power them to a full operational current of 250 A. Cryogenic Hall sensors measure the field in the magnet bore during testing. Techniques to measure the field profile and the integrated field components inside the small, closed magnet bore have also been developed. These measurements are crucial for understanding the magnetic performance of the prototype magnets and identifying and implementing suitable corrections to the field integrals. We present here the first cooling and magnetic field measurement results of the prototype undulators.
Paper: MOPM113
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM113
About: Received: 26 Apr 2023 — Revised: 23 May 2023 — Accepted: 23 May 2023 — Issue date: 26 Sep 2023
MOPM115
Preliminary design of insertion devices at Hefei Advanced Light Facility
1247
Hefei Advance Light Facility (HALF) is a 2.2 GeV diffraction-limited storage ring, which is developed by National Synchrotron Radiation Laboratory in China. It has 20 long straight sections and 20 middle straight sections. All the experimental stations in the first stage will employ undulator as the light source. In this paper, we introduce the preliminary design of insertion devices of HALF, which includes 11 undulators and 2 wigglers. The undulator design is carefully optimized based on the current undulator technology and experiment user demands. The photon flux of these undulators can cover the photon energy from 5 eV to 10 keV with the flux greater than $10^{14}$ phs/s/0.1\% B.W. It can reach an ultra-high brilliance at the soft X-ray wavelength region. Most of the insertion devices are the elliptically polarized undulators and the in-vacuum undulators, therefore the light source of HALF will be charactered by a flexible tunability on polarization state and a broad range of photon energy from VUV to X-ray wavelength region.
Paper: MOPM115
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM115
About: Received: 28 Apr 2023 — Revised: 11 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
MOPM116
Theoretical studies on polarization control of segmental undulator system
1250
Polarization control of undulator radiation attracts a great attention due to its application prospects in material and biology. Various undulators have been developed to obtain radiation of specific polarization states. In the electron storage ring light source, different methods have been proposed to realize a specific polarization switching. However, there is still a strong demanding to improving the switching speed and/or increasing the available polarization state in a single beam line. This paper gives systematic analysis of simple schemes to obtain the polarization switching by using the segmentation of the undulators with the phase shifter placed between each adjacent undulators. Through switching the polarization state of each undulator and the phase shifts, the polarization state can be fast switched between different polarization states in a same undulator line. The theoretical analysis for the radiation characteristics under different undulator configurations are demonstrated to reveal the basic principle of this simple method.
Paper: MOPM116
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM116
About: Received: 03 May 2023 — Revised: 11 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
Burst mode compact optical cavity for Inverse Compton scattering sources
Inverse Compton Scattering is a promising technique to deliver compact, high brightness and high rate sources of photons ranging from few keVs to several MeVs. Current projects either focus on producing high rates of photons thanks to high-power (up to 300kW) enhancement optical cavities and electron storage rings or on providing low bandwidth photon sources based on room-temperature linacs. Burst mode operated optical enhancement cavities coupled to pulsed RF muti-bunch linac systems have the potential to provide high quality and high rate at the same time. To this end we concentrate on realizing innovative systems operated at GHz frequencies with repetition rates of several hundreds of hertz corresponding to linac RF-pulsing capabilities. Recent experimental advances, made within a collaboration between Amplitude and IJCLab, in the realization of a compact enhancement cavity seeded by a GHz laser and operated in burst mode are described. Performance will be reported along with prospects for improvements.
High Finesse Fabry-Perot Cavity for ThomX ICS as an X-ray Source
Inverse Compton scattering (ICS) is a method used for X-ray production that has been possible in recent years due to the rapid development of ultra-fast, short, and stable oscillators. In addition, the research and development of high Finesse Fabry-Perot Cavities to store high average power inside it. ThomX is a new generation of compact X-ray source which implements the ICS method. It will produce higher flux and better quality X-rays than the traditional sources such as X-ray tubes and be cheaper and more compact than synchrotrons. ThomX is currently being commissioned in IJCLab ( Laboratory de physique des 2 infinitis – Irene Joliot Curie ) at the Orsay campus. It is composed of a linear accelerator that can accelerate the electron bunch up to 50 MeV, an electron ring to store it over multiple revolutions at 16.66 MHz, and a Fabry Perot cavity to maintain the photon pulse at 33.33 MHz. The first electron beam produced was in October of 2021, and then it had a full round in the storage ring in 2022. It is expected to produce x-rays in mid-2023 when its Optical cavity has power stored in it. It is a high Finesse Fabry-Perot cavity that can store up to 1 MW. Such cavities face many problems, from high power stability to heating up of their reflecting mirrors. Here, we will describe the optical cavity commissioning of ThomX and the challenges faced throughout the preparation for the production of X-rays.
MOPM123
Cavity mirror development for optical enhancement cavity of steady-state microbunching light source
1254
Optical enhancement cavity (OEC) provides the high intensity and high stability modulation laser field in steady-state microbunching (SSMB) light source. An SSMB extreme ultraviolet (EUV) light source targeted for lithography application is currently being developed at Tsinghua University, which demands for megawatt scale intra-cavity power for OEC. Cavity mirrors are the key components of the OEC to realize its designed parameters. Here we report the development progress of the cavity mirrors.
Paper: MOPM123
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM123
About: Received: 02 May 2023 — Revised: 06 Jun 2023 — Accepted: 06 Jun 2023 — Issue date: 26 Sep 2023
MOPM125
Study on a self-resonating optical cavity for high-brightness Laser-Compton Scattering X-ray sources
1257
Laser Compton Scattering (LCS) is a technique to produce quasi-monochromatic X-rays and gamma rays by colliding a laser with a high-energy electron beam produced by an accelerator. Although LCS light sources are expected to produce photons of the same quality in a small (6m x 8m) device as those from large synchrotron radiation facilities , the low number of scattered photons is an issue for practical use. To solve this problem, we have developed an optical cavity to generate colliding lasers with high repetition rate and high peak power. However, the operation of an optical cavity in an accelerator environment with high noise limits the stored optical power by maintaining resonance through resonator length control. Therefore, we have devised and are developing a self-resonating optical cavity in which the resonance is maintained spontaneously by connecting the optical storage resonator and the laser oscillator in a closed loop. In this talk, I will report on the current status of self-resonating optical cavity and its temperature dependence.
Paper: MOPM125
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM125
About: Received: 24 Apr 2023 — Revised: 05 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
MOPM126
Tunable monochromatic gamma ray source design using Inverse Compton Scattering at Daresbury Laboratory
1260
Inverse Compton Scattering (ICS) is an ideal source of tunable monochromatic gamma rays. These gammas have uses for Nuclear Resonance Fluorescence, and production of novel medical radioisotopes. The gamma energy can be tuned by changing the electron energy. An ICS source can be made quasi-monochromatic by using low energy spread electron and laser beams, and using a collimator. Currently ICS gammas are only available from large synchrotron driven electron sources. These sources suffer from a smaller flux in the desired bandwidth than ERLs or linacs. A new planned gamma source is under consideration as part of the proposed UK-XFEL project, this would involve part of the XFEL linac being enabled for an energy recovery mode. A demonstrator experiment to support the UK-XFEL project is being discussed for the upgraded CLARA facility at Daresbury Laboratory. The experiment will scatter Ti:Sapphire laser pulses at 800 nm off 250 MeV electrons. The gammas will be collimated. This experiment will characterise the source to determine the bandwidth and flux of the source. The maximum energy of the gamma photons in this experiment is 1.48 MeV and the bandwidth of the collimated source is 3.2%. In this work I will present simulations of the planned experiment, showing the scattered gamma energy, bandwidth and tunability of the source.
Paper: MOPM126
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM126
About: Received: 02 May 2023 — Revised: 07 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
MOPM127
Photon diagnostics for the high-gain THz FEL at PITZ
1263
Research and development of an accelerator-based THz source prototype for pump-probe experiments at the European XFEL are ongoing at the Photo Injector Test Facility at DESY in Zeuthen (PITZ). Proof-of-principle experiments have been performed to generate a high-gain THz Free-electron Laser (FEL) based on the Self-Amplified Spontaneous Emission scheme. The FEL radiation pulses with a central wavelength of about \SI{100}{\micro\metre} (\SI{3}{\tera\hertz}) and single pulse energy of several tens~\SI{}{\micro\metre} can be generated. In this paper, we present and discuss the photon diagnostic setup for the THz FEL together with examples of diagnostic results, including pulse energy and an FEL gain curve. The upgraded photon diagnostic setup, capable of measuring pulse energy, transverse distribution, and spectral distribution, is expected to be operational in the spring of 2023.
Paper: MOPM127
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM127
About: Received: 26 Apr 2023 — Revised: 05 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
Evaluation of photon energy and bandwidth jitter of SASE-FEL beam using hard X-ray spectrometer at European XFEL
The European X-ray Free Electron Laser (EuXFEL) is a user facility delivering soft and hard X-ray FEL radiation. It provides X-rays with high brilliance and intensities in the photon energy range of 0.5 keV to 25 keV. 2700 pulses at 10 Hz with femtosecond up to 4.5 MHz pulse repetition rate. The FEL radiation which is created by the Self Amplified Spontaneous Emission (SASE) process, whose stochastic nature gives rise to shot-to-shot fluctuations of the pulse energy and spectrum. In order to cover these variations, the HIgh REsolution hard X-ray single-shot (HIREX) spectrometer has been installed in the Hard X-ray beamlines SASE1 and SASE2. The HIREX spectrometer is an online device, based on a bent diamond and Silicon crystal as a dispersive element and a MHz-repetition rate GOTTHARD strip detector. The SASE2 HIREX spectrometer is identical to the HIREX spectrometer installed at SASE1 with the difference that it does not provide gratings that can be used as a beam splitter. Thus, the spectrometer crystal has to be placed in the direct beam to collect energy spectra. In this contribution, we will present the measurement results of central photon energy and bandwidth jitter of the SASE-FEL beam at different photon energies. Further, we will also focus on the automation of the HIREX spectrometer for instrument beamlines with a single push button.
Thermal Load Analysis and Benchmark Study for Beamline of Low Emittance Storage Ring
The Korea-4GSR with low emittance of 60 pm-rad provides the photon beam that is 100 times brighter and 100 times more coherent than PLS-II. Despite these powerful advantages, the new source imposes high power density on beamline optics. In particular, the first mirror M1 receiving broadband white beam will be directly affected. To check this, we calculated the power density by introducing a new ray-tracing algorithm. And this result is converted to temperature through Ansys steady-state thermal. The consistency of this calculation was evaluated as the measured value of M1 being monitored in PLS-II BL8A. This paper shows the results of the above.
MOPM130
Calibration of the 2-phase bubble tracking model for liquid mercury target simulation with machine learning surrogate models
1267
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is one of the most powerful accelerator-driven neutron sources in the world. The intense protons strike on SNS’s mercury target to provide bright neutron beams, which also leads to severe fluid-structure interactions inside the target. Prediction of resultant loading on the target is difficult particularly when helium gas is injected into mercury to reduce the loading and mitigate the pitting damage on vessel walls. A 2-phase material model that incorporates the Rayleigh-Plesset (R-P) model is expected to address this multi-physics problem. However, several uncertain parameters in the R-P model require intensive simulations to determine their optimal values. With the help of machine learning and the measured target strain, we have studied the major uncertain parameters in this R-P model and developed a framework to identify optimal parameters that significantly reduce the discrepancy between simulations and experimental strains. The preliminary results show the possibility of using this mercury/helium mixture and surrogate models to predict a better match of target strain response when the helium gas is injected.
Paper: MOPM130
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM130
About: Received: 10 May 2023 — Revised: 19 Jun 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
MOPM132
Recent progress of Shanghai laser electron gamma source (SLEGS) beamline in SSRF
1271
Shanghai Laser Electron Gamma Source (SLEGS) beamline, based on laser Compton scattering (LCS), as one of beamlines of Shanghai Synchrotron Radiation Facility (SSRF) in phase II project, has been construct-ed and started test commissioning from July 2021. The results of the commissioning already show a steady experimental proof that SLEGS can produce gamma rays with adjustable maximum energy by consecutive-ly changing the interaction angle between laser beam and electron bunches. In this paper, the recent progress of SLEGS is given. The newly measured gamma-ray’s spectra and flux are presented. The resolution of the gamma-rays is im-proved with the application of external collimator. A gamma spot monitor is setup to measure the spatial distribution of LCS gamma ray. A 4π flat-efficiency 3He neutron detector (FED) array and the neutron time-of-fight (TOF) spectrometer are also designed and installed. Some preliminary results of these devices is introduced.
Paper: MOPM132
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM132
About: Received: 02 May 2023 — Revised: 10 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
Gamma-ray-induced positron annihilation spectroscopy at UVSOR-III BL1U
We are developing gamma-ray-induced positron annihilation spectroscopy (GiPAS) using ultra-short pulsed gamma rays at the UVSOR synchrotron facility in Japan. The gamma rays with the pulse width of picosecond range are generated by 90-degree inverse Compton scattering between a 750 MeV electron beam and an 800 nm laser. As the energy of the gamma rays is 6.6 MeV, gamma-ray irradiation produces positrons by pair production inside the material. Generated positrons localize on atomic-scale defects in solid crystals, such as vacancies, dislocations, and vacancy clusters. Positronium, the bound state of an electron-positron pair, localizes in vacant space caused by the free volume in polymers. Therefore, positrons are excellent probes of the nanostructure of these materials. Furthermore, the circularly polarized gamma rays generated by a circularly polarized laser can produce spin polarized positrons. The spin polarized positrons provide additional information about the electron spins around defects. GiPAS is currently available for users in UVSOR-III. In this conference, we will present a generation method of the ultra-short pulsed gamma-rays and details of GiPAS*.
MOPM135
Compression of relativistic electron bunch train
1274
We presented a novel concept of longitudinal bunch train compression capable of manipulating relativistic electron beam in range of hundreds of meters. It has potential to compress electron beam with high ratio, and raise its power to ultrahigh level within compressed duration of nanoseconds. Electron’s spiral motion in uniform magnetic field is utilized to fold the hundreds of meters long trajectories into a compact setting. Helix angle of bunches’ spiral track are adjusted by a local time-varying magnetic field. Spiral pitch of each bunch gets gradually increased from the leading edge toward trailing edge of the train. After the spiral procedure, interval between bunches is redefined and the compression is realized. The method is explored both analytically and numerically. Compared to microbunching or chicane modulation, this method could compress bunches at distinct larger scales, opening up new possibilities for generation of beam with ultra-large power storage.
Paper: MOPM135
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM135
About: Received: 26 Apr 2023 — Revised: 06 Jun 2023 — Accepted: 06 Jun 2023 — Issue date: 26 Sep 2023
MOPM136
Design of an S-band buncher for KeV UED
1277
High power input often leads to frequency deviation that cannot meet the high-precision frequency control requirements of keV Ultrafast Electron Diffraction (UED) compression cavities. In this paper, we propose new solu-tions for reducing heat generation and frequency devia-tion based on modifications to the cavity design and power input method, building upon the design of the orig-inal elliptical cavity. These solutions have been verified through simulation calculations. In pulsed input mode, the cavity temperature rise is within 2℃, and in continu-ous wave mode, the new cavity design can withstand temperature rises of up to 20℃, both of which meet the requirements of practical engineering.
Paper: MOPM136
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM136
About: Received: 03 May 2023 — Revised: 20 Jun 2023 — Accepted: 20 Jun 2023 — Issue date: 26 Sep 2023
MOPM137
Development of an X-band RF gun with four-feed coupler
1280
With the high accelerating gradient, radiofrequency (rf) gun has a significant feature of suppressing the growth of transverse emittance caused by space charge. Field emission cathodes were first used in vacuum electronic devices, which do not require the high electron beam intensity, but the cathode size and integrality. A new X-band (11.424 GHz) rf electron gun has been proposed with the highlight of four-feed coupler, which can eliminate the quadrupole field component observed and analyzed from the imagine experiment, which have affected the resolution of the imaging system to some content.
Paper: MOPM137
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM137
About: Received: 14 May 2023 — Revised: 17 May 2023 — Accepted: 23 Jun 2023 — Issue date: 26 Sep 2023
MOPM138
Assembly, alignment and tuning of the XiPAF DTL
1284
A 7 MeV Alvarez-type drift tube linac (DTL) had been designed and machined in the past few years for Xi'an 200 MeV proton application facility (XiPAF). This paper presents the assembly, alignment, error analysis and tuning results of the DTL. After all these tasks were completed at Tsinghua University, the DTL cavity had been transported to Xi'an for repetition measurement and test. It has been aligned on the beamline for RF conditioning and beam commissioning.
Paper: MOPM138
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM138
About: Received: 05 May 2023 — Revised: 23 Jun 2023 — Accepted: 23 Jun 2023 — Issue date: 26 Sep 2023
MOPM140
X-band electron linear accelerator design for intraoperative radiotherapy
1288
In intraoperative radiation therapy (IORT), accelerators typically consist of two or more tubes to achieve adjusta-ble electron energy. To simplify the accelerator structure and meet the demand for convenient adjustment of elec-tron energy, we propose an X-band electron linear accel-erator for IORT, composed of 102 cavities. This accelera-tor can adjust the output electron energy over a large range solely by varying the input power, providing elec-trons with energy exceeding 13MeV at maximum and approximately 5.5MeV at minimum, which satisfies the requirements of electron IORT. We also measured the field distribution and S-parameters at low power, and the ener-gy spectrum distribution also was measured at different input powers. This accelerator design provides a feasible and simple solution for IORT-specific accelerators.
Paper: MOPM140
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPM140
About: Received: 30 Apr 2023 — Revised: 07 May 2023 — Accepted: 23 Jun 2023 — Issue date: 26 Sep 2023