linac
MOYD1
LCLS-II commissioning results
13
LCLS-2 should be completed in 2022, producing first light from its new SC linac. The status of beam commissioning and the performance of the new SC CW linac should be shown in detail. Performance should be compared with the design values and an outlook to further steps should be shown.
Paper: MOYD1
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOYD1
About: Received: 03 May 2023 — Revised: 05 Jun 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
MOYD2
LIPAc (linear IFMIF prototype accelerator) beam commissioning & future plans
15
The Linear IFMIF Prototype Accelerator (LIPAc) has been constructed in Rokkasho, Japan to demonstrate the validity of the low energy section of an IFMIF deuteron accelerator up to 9 MeV with a beam current of 125 mA in continuous wave (CW) under the joint collaboration between EU and Japan. The short-pulse 125-mA deuteron beam acceleration to 5 MeV was successfully demonstrated in 2019. Now LIPAc is under commissioning toward the CW beam acceleration. The effort to realize the high-current CW beam, e.g. the commissioning of the ion source at high-current, CW and the conditioning of the RFQ cavity at CW, and the result of the beam commissioning campaign will be presented.
Paper: MOYD2
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOYD2
About: Received: 03 May 2023 — Revised: 13 Jun 2023 — Accepted: 12 Jun 2023 — Issue date: 26 Sep 2023
MOOD1
Time-drift aware RF optimization with machine learning techniques
38
The Fermilab Linac delivers 400 MeV H- beam to the rest of the accelerator chain. We are exploring several machine learning (ML) techniques for automated RF tuning, with an emphasis on time-evolving modeling that can account for parameter drift. Providing stable intensity, energy, and emittance is key since it directly affects downstream machines. To operate high current beam, accelerators must minimize uncontrolled particle loss; this ca be accomplished by minimizing beam longitudinal emittance via RF parameter optimization. However, RF tuning is required daily since the resonance frequency of the accelerating cavities is affected by ambient temperature and humidity variations and thus drifts with time. In addition, the energy and phase space distribution of particles emerging from the ion source are subject to fluctuations. Such drift is not unique to Fermilab, but rather affects most laboratories. Our methods include several variations of RF system modeling based on diagnostics data from beam position monitors (transverse positions and longitudinal phase). We will present the status of each approach and future plans.
Paper: MOOD1
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOOD1
About: Received: 12 May 2023 — Revised: 22 May 2023 — Accepted: 22 May 2023 — Issue date: 26 Sep 2023
MOOG1
X-band activities at INFN-LNF
42
The Eupraxia@SPARC_LAB project, foreseen a 1GeV Linac based on a X-band booster composed by 16 accelerating structures working at the nominal gradient of 60MV/m. In this framework, an intense activity has started in the last years in order to prove the reliability and functionality of the X-band technology at very high peak power. The main step of this activity has been the implementation of a X-band test station TEX, based on an RF power source capable to deliver 50MW RF pulses that are used for accelerating structures and RF components conditioning and testing. This test facility has been successfully commissioned and entered into operation at the end of 2022. Together with the source commissioning different RF components in X-band, necessary for the Eupraxia Linac, have been developed and will be tested soon at the nominal peak power in the TEX facility. In this article the status and operation of the TEX facility is reported together with a report on the main activities on the X-band technology performed at INFN-LNF.
Paper: MOOG1
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOOG1
About: Received: 03 May 2023 — Revised: 19 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
MOPA004
Double achromat solution with a dedicated collimation system for the MEBT-3 section of MYRRHA
63
MINERVA (MYRRHA phase 1) aims at demonstrating the requirements related to the reliability and the fault tolerances of the MYRRHA accelerator-driven system (ADS) by the realization of a superconducting linac for 100 MeV/4 mA proton beams. The design and the performance of the Medium Energy Beam Transfer section (referred to as MEBT-3) of the accelerator are critical for reaching the goals of MINERVA. The purpose of the MEBT-3 is to fast-switch between a 17 MeV beam coming from one injector to another to ensure a continuous injection of 17 MeV proton beam in the main superconducting linac, in case one of the injectors would fail. The design goals of the MEBT-3 are to reach maximal beam transmission, accurate beam definition for matching the linac and a double achromaticity after the last switching dipole. For the protection of the main linac, a dedicated collimation system consisting of multiple slits was designed and incorporated into the MEBT-3 section. The expected performance of the MEBT-3 has been studied extensively by beam dynamics simulations in order to reach the desired specifications. The non-accelerating MEBT-3 section includes multiple transverse and longitudinal beam focusing elements, such as magnetic quadrupoles and room temperature re-bunchers. The latest beam dynamics studies for achieving the MEBT-3 design goals will be presented.
Paper: MOPA004
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPA004
About: Received: 02 May 2023 — Revised: 05 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPA018
High order mode analysis in energy recovery linac based on an energy budget model
77
Energy Recovery linear accelerator (ERL) light source facilities based on superconducting radiofrequency (SRF) are deemed of the most resplendent techniques in the future of accelerator physics. Running in a continuous waves mode with a high repetition rate for a long timescale, we discuss High order modes (HOMs) analysis in a two-pass two-way ERL scheme where acceleration and deceleration of electron bunches are supported by a standing wave structure of the RF cavity. The analysis reported in this paper is based on differential equations that describe the beam dynamics (BD) to overcome the limitations imposed by high currents and insure energy recuperation over millions of interactions.
Paper: MOPA018
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPA018
About: Received: 03 May 2023 — Revised: 07 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
MOPA023
Magnetic design of the commutational magnet and quadrupoles for PERLE accelerator
85
PERLE (Powerful Energy Recovery LINAC for Experiment) is a high-power Energy Recovery LINAC (ERL) facility with 20 mA beam current and beam energy from 250 MeV to 500 MeV featuring three passes through two cryomodules. It is a hub for validation of the ERL technology development towards future energy and intensity frontier machines. Design challenges of PERLE and its beam parameters make it a testbed to validate multi-turn high current ERL operation for the LHeC. It will be the first ERL for some pioneering experiment of the eN interaction with radioactive nuclei. In this work, design and optimization of the commutational magnet (B-com) used to spread/combine the three beams and one series of the quadrupole magnet is discussed. It gives the design parameters including: yoke geometry, pole profile, and material, and calculation of the excitation current needed to drive the magnet, the coil parameters and the number of turns. The B-com magnet is optimized for a 30° bending angle with magnetic field of 0.88 T along the magnet length and a harmonic content of 0.036%. The quadrupole magnet is designed for a gradient field of 34.15 T/m and experiences saturation above this value. Further studies to avoid saturation and achieve the maximum gradient of 44.1 T/m required by the beam dynamics is undergoing.
Paper: MOPA023
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPA023
About: Received: 28 Mar 2023 — Revised: 10 May 2023 — Accepted: 20 Jun 2023 — Issue date: 26 Sep 2023
MOPA025
First coaxial HOM coupler prototypes and RF measurements on a copper cavity for the PERLE project
89
The PERLE (Powerful Energy Recovery Linac for Experiments) project relies on superconducting RF (SRF) cavities to reach its goals. The installation of coaxial couplers on the cutoff tubes of SRF cavities is foreseen for damping cavity’s Higher Order Modes (HOMs). The prototyping and fabrication of 3D-printed HOM couplers for the PERLE cavity have recently started in collaboration with JLab and CERN. This paper provides an overview of the design of the fabricated HOM couplers and the first RF measurements of the cavity’s HOMs performed at warm on an 801.58 MHz 2-cell copper cavity to validate coupler design performances. Measured cavity data is also compared to eigenmode simulations to confirm simulated results and see to what extent any reduction in damping can be predicted.
Paper: MOPA025
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPA025
About: Received: 10 May 2023 — Revised: 12 May 2023 — Accepted: 22 Jun 2023 — Issue date: 26 Sep 2023
MOPA112
Damping ring and transfer lines of FCC-𝑒+𝑒− injector complex
308
The Future Circular Collider project is built around two main pillars: the construction of 100 km lepton collider running at increasing energies from the Z-pole to the t-tbar threshold (FCC-ee) followed by a hadron collider in the same tunnel (FCC-hh) to explore unprecedented energy frontier. The realization of FCC-ee relies on a very challenging injector complex that should provide the highest ever realized source of positrons, which will serve the first phase of the collider operations (Z-pole). In this contribution the relevant aspects related to the damping of the high-emittance beam coming from the positron source and the transport of the damped beam within the different LINAC of the injector complex are presented and discussed.
Paper: MOPA112
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPA112
About: Received: 03 May 2023 — Revised: 06 Jun 2023 — Accepted: 06 Jun 2023 — Issue date: 26 Sep 2023
MOPA151
Complex bend prototype beamline design and commissioning
408
Modern synchrotron light sources are competing intensively to increase X-ray brightness and, eventually, approach the diffraction limit, which sets the final goal of lattice emittance. Recently, we propose a new optics solution aimed at reaching low emittance, using a lattice element “Complex Bend”. The Complex Bend is a sequence of dipole poles interleaved with strong alternate focusing so as to maintain the beta-function and dispersion oscillating at low values. By integrating this element in NSLS-IIU upgrade, the designed lattice emittance is around 30 pm-rad. To prove the feasibility of this new design, we have planned the key element prototype test, in the beam line with 200 MeV beam energy. We designed and fabricated the prototype complex bend, with gradient at 140 T/m. It is installed and commissioned at NSLS-II linac beamline. In this paper, we’ll report the test beamline design and beam commissioning progress
Paper: MOPA151
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPA151
About: Received: 03 May 2023 — Revised: 08 Jun 2023 — Accepted: 08 Jun 2023 — Issue date: 26 Sep 2023
MOPA161
Adaptable gun pulser suitable for single bunch and programmed multibunch top-up and fill of storage ring light source
430
Diamond Light Source has been operating in top-up mode for users since late 2008. To date, Diamond’s electron gun has operated in single-bunch mode for multiple-shot top-up of user beam, and multibunch mode for storage ring fill. The uneven bunch-to-bunch charge of the multibunch train is visible in the storage ring and so the fast multibunch fill must be followed by a slower single bunch correction before beam can be given to users. A new pulser has been developed that will generate a flat, fast-rising 500 MHz train of electron bunches from the gun that will enable a uniform fill of the storage ring without single bunch correction. Arbitrary bunch-by-bunch shaping of the train can be used for multibunch fill and top-up of any required fill pattern, thus exploiting the greater charge available in multibunch mode to reduce the number of top-up shots and consequent disturbance to users. Pulser development and results are presented, together with a report of progress towards multibunch top-up.
Paper: MOPA161
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPA161
About: Received: 03 May 2023 — Revised: 10 May 2023 — Accepted: 22 Jun 2023 — Issue date: 26 Sep 2023
MOPA188
Design of a 250 linac injector for the Southern Advanced Photon Source
496
The Southern Advanced Photon Source (SAPS) is a 4th generation storage ring based light source under design started several years ago, which is planned to be constructed at Guangdong province at China. The equilibrium emittance of the storage ring will be below 100 pm.rad and the beam energy is determined to be 3.5 GeV. During the past two years, the nominal current of the storage ring was increased from 200 to 500 mA, so the injector system has to provide more bunch charge. Besides, the injection beam energy for the booster was increased from 150 to 250 MeV, which means two more accelerating cavities have to been added. In this paper, the update of the linac injector is presented, which consists of a thermionic electron gun, a bunching system, a 200 MeV linac. The beam transfer line from linac to booster is also presented
Paper: MOPA188
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPA188
About: Received: 31 Mar 2023 — Revised: 11 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
MOPL016
Advancements in injection efficiency modelling for the Low Energy Ion Ring (LEIR) at CERN
539
The performance of the Low Energy Ion Ring (LEIR) at CERN is mainly determined by the number of charges extracted from the machine and transferred to the downstream chain of accelerators. While the required target of 9e10 charges has now been surpassed, a series of studies have been undertaken to further push the intensity reach of LEIR. In this work, we quantify the effect of the stray fields generated by the adjoining Proton Synchrotron (PS), which were recently partially shielded, and the effect of the stripper foil in the Linac supplying LEIR with its ions, Linac 3. The impact of the stray field was measured by observing the variation in injection trajectory, while that of the stripper foil was determined from the evolution of the Schottky energy profile in LEIR. Models have been developed to extrapolate the impact of these effects to the injection efficiency of LEIR, and consequently to the extracted beam intensity.
Paper: MOPL016
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL016
About: Received: 24 Apr 2023 — Revised: 08 Jun 2023 — Accepted: 08 Jun 2023 — Issue date: 26 Sep 2023
MOPL051
CEPC damping ring design in TDR stage
654
A damping ring system which includes a small 1.1 GeV ring and two transport lines is introduced in CEPC linac in order to reduce the transverse emittance of positron beam at the end of linac and hence reduce the beam loss in the booster. The repetition rate of Linac is 100 Hz and one-bunch-per-pulse is considered. The double-bunch scheme of Linac is only considered for the high luminosity mode at Z pole. The positron beam is generated by 4 GeV electron beam hitting tungsten target and then is captured by an AMD flux concentrator. Each positron bunch is injected into damping ring every 10 ms and two bunches are stored in the ring so that the storage time for each bunch is 20 ms. The bunch number in the damping ring can be increased to 4 with an upgrade and hence the storage time for each bunch can be increased to 40 ms. The reversed bending magnet scheme is adopted for TDR in order to reduce the emittance significantly. The normalized emittance of positron beam is expected to be reduced from 2500 mm.mrad to 166 mm.mrad (or 97 mm.mrad) in the damping ring.
Paper: MOPL051
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL051
About: Received: 28 Apr 2023 — Revised: 10 May 2023 — Accepted: 20 Jun 2023 — Issue date: 26 Sep 2023
MOPL086
On positron beam dynamics an initial part of a large aperture FCC-ee capture linac
760
The application of HTS coils as a matching device and a large-aperture L-band linac make it possible to transport a substantial part of positrons generated in a positron production target through a capture linac. It raises a question of how to manage their large phase space to provide bunches matched to the damping ring acceptance. This paper presents the beam dynamics studies of the FCC-ee positron linac consisting of an adiabatic matching device (AMD) with theoretical field distribution combined with constant solenoidal field along $\frac{9}{10}\pi$ large aperture L-band accelerating sections. AMD field drop rate, as well as the RF field phase and accelerating section length, were varied to find features of a bunch formation. It was shown that 5D normalized beam brightness is a useful parameter to optimize the initial part of the capture linac. A higher beam brightness can be obtained for the higher AMD field drop rate. Starting from some accelerating section length, two peak structure appears in the normalized brightness dependence on the RF field phase. The peaks correspond to the acceleration of the head or the tail of the initial positron longitudinal distribution. The last one provides a higher positron yield.
Paper: MOPL086
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL086
About: Received: 03 May 2023 — Revised: 12 May 2023 — Accepted: 23 Jun 2023 — Issue date: 26 Sep 2023
MOPL094
Benchmarking the FCC-ee positron source simulation tools using the SuperKEKB results
772
For the Future Circular Collider (FCC-ee), particular attention is drowned to the crucial role of the positron source. Two positron production schemes are considered for the FCC-ee: conventional and crystal-based (hybrid), implying the use of channeling radiation in the oriented crystals. To design and optimize the positron production and capture by considering the positron injector parameters, including the electron drive beam and the final system acceptance, a start-to-end simulation toolkit should be developed. This paper will present the first results of benchmarking the FCC-ee positron source simulation tools using the SuperKEKB positron source currently in operation. The model starts with the production of positrons and target studies in Geant4. Then, a new tracking code RF-Track is used for capturing and tracking the generated positrons through the capture section composed of the matching device and several accelerating structures embedded in the solenoid field to accelerate the positrons until ~120 MeV. Afterward, the positrons are further accelerated to the energy of the Damping Ring (1.1 GeV).
Paper: MOPL094
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL094
About: Received: 04 May 2023 — Revised: 22 May 2023 — Accepted: 22 May 2023 — Issue date: 26 Sep 2023
MOPL095
Update on the FCC-ee positron source design studies
776
The studies and R&D on the high-intensity positron source for the FCC-ee have been initiated for a while. The positrons are produced by a 6 GeV electron drive-beam incident on a target-converter at 200 Hz. The drive beam comes in 2 bunches spaced by 25 ns with a maximum charge of ~5 nC per bunch. Two scenarios using conventional and hybrid targets are being studied for positron production. According to the FCC CDR, the Flux Concentrator is used as the matching device for the capture system, followed by several accelerating structures embedded in the solenoidal field. Then, the positrons are further accelerated to be injected into the damping ring. Recently, the feasibility study on using a SC solenoid for the positron capture has been started, and the design based on the HTS technology is under investigation. In addition, the large aperture 2 GHz RF structures, which have been specially designed for the FCC-ee positron capture system, are used with the goal of demonstrating accepted positron yield values well beyond the values obtained with state-of-the-art positron sources. The purpose of this paper is to review the current status of the FCC-ee positron source design, highlighting the recent research into the positron production, capture system, primary acceleration, and injection into the damping ring.
Paper: MOPL095
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL095
About: Received: 05 May 2023 — Revised: 05 Jun 2023 — Accepted: 05 Jun 2023 — Issue date: 26 Sep 2023
MOPL096
Use of a superconducting solenoid as a matching device for the compact linear collider positron source
780
A matching device with a strong magnetic field is used to capture positrons in the positron source of future e+e- colliders such as the Compact LInear Collider (CLIC) and the Future Circular Collider (FCC-ee). Compared to conventional matching devices such as flux concentrators, superconducting (SC) solenoids can have a much higher peak field, improving the capture efficiency and the positron yield. In this paper, we tested an analytic SC solenoid field and simulated the matching device for the CLIC positron source. Furthermore, we optimised the coil parameters for maximum positron yield. The results from a study of the latest high temperature superconductor based solenoid designed by PSI for the FCC-ee positron source is also presented.
Paper: MOPL096
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL096
About: Received: 02 May 2023 — Revised: 12 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
MOPL098
Helen: Traveling wave SRF Linear Collider Higgs factory
788
Travelling wave (TW) SRF accelerating structures offer several advantages over the traditional standing wave structures: substantially lower Hpk/Eacc and lower Epk/Eacc, ratios of peak magnetic field and peak electric field to the accelerating gradient, respectively, together with substantially higher R/Q. In this paper we discuss how a linear collider Higgs factory HELEN can be built using TW-based SRF linacs. We cover a plan to address technological challenges and describe potential ways to upgrade the collider luminosity and energy.
Paper: MOPL098
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL098
About: Received: 03 May 2023 — Revised: 09 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPL101
Design, testing, and validating the CLIC module pre-alignment and alignment systems
800
In order to produce a high luminosity at the interaction point, the Compact Linear Collider (CLIC) accelerators must preserve low emittance beams along both the main 22km linacs. A key factor in preserving a low emittance beam is the mechanical alignment and stability of the accelerator components. The CLIC accelerators are divided into `Two Beam Modules’ (TBMs) which integrate a section of the power-delivering Drive Beam and the accelerating Main Beam. The Main Beam is accelerated within Acceleration Structures that require prealignment to within 14 µm of the Metrological Reference Network (MRN). To prevent a greater than 1% luminosity loss, the vertical jitter of the accelerator components must be kept below 1.4µm RMS when the TBMs are exposed to the ground noise within the tunnel, and other sources of vibration. A design of the TBMs is presented which includes active alignment, passive prealignment, and sufficient mechanical stability to meet the specification. Finite Element Analyses (FEA) are used to demonstrate the suitability of this design. The results of the testing of prototype SAS prealignment and active TBM positioning systems are discussed and shown to meet the CLIC alignment requirements. Opportunities for future testing and areas for further optimisation are identified and discussed.
Paper: MOPL101
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL101
About: Received: 06 Apr 2023 — Revised: 23 May 2023 — Accepted: 23 May 2023 — Issue date: 26 Sep 2023
MOPL108
Study of a bunch train total energy spread in a Linac using SLED
810
A SLED (SLac Energy Doubler) RF pulse compressor is a passive RF component which increases the peak RF power level at the cost of reducing the pulse length. The Canadian Light Source (CLS) plans to replace the current 250 MeV Linac with a new one in mid-2024 by RI Research Instruments GmbH. The new Linac has a similar energy and two of its three 5.3 m TW constant-gradient accelerating structures are connecting to a SLED. Since a SLED output is not flat, this introduces additional energy variation along a bunch train, increasing the total energy spread. In addition, the energy spread acceptance of the CLS booster ring is below 0.5% FWHM, and it is critical to minimize the SLED non-flatness output effect by different methods. This paper will study the SLED effect on a multi-bunch train energy variation and consider the transient beam loading effect. Finally, we will show that by selecting proper RF phase switching and beam injection timing, and by alternating energy gain slope between the SLED-ed and non-SLED-ed Linac cavities can achieve the required energy spread.
Paper: MOPL108
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL108
About: Received: 02 May 2023 — Revised: 22 May 2023 — Accepted: 22 May 2023 — Issue date: 26 Sep 2023
MOPL111
An iterative algorithm to estimate the energy spectrum of an electron beam from PDD curves
814
Electron beam central-axis percentage depth dose (PDD) curves in water phantom are routinely employed to evaluate the electron beam energy at the phantom surface, in particular the mean and most probable energies from the values of R50 (half-value range) and Rp (practical range). However, these two quantities are not enough to evaluate important details of the energy distribution, such as the FWHM (Full Width Half Maximum) and the possible presence of a low-energy tail. This paper presents a numerical method that allows estimating the shape of the energy spectrum from a PDD curve. The algorithm uses a database consisting of a set of depth dose curves for monochromatic beams computed by FLUKA in the range 0.1-6.0 MeV by steps of 0.1 MeV and, using an adaptive iterative Monte Carlo process, reconstructs the incident energy spectrum by minimizing the distance between the measured PDD and the computed one. Applications of a MATLAB code based on this algorithm to simulated and real measurements of electron beams done at APAM lab (ENEA Frascati) are presented. This approach represents a strong simplification with respect to energy analysis based on the use of a magnetic spectrometer.
Paper: MOPL111
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL111
About: Received: 03 May 2023 — Revised: 07 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
MOPL120
Beam injection issues at SuperKEKB
832
A high-charge, low-emittance injection beam is essential for SuperKEKB. For its both rings, HER and LER, the injection efficiencies and detector backgrounds have not been good enough up to the recent run. There are many reasons for the issues. For example, serious emittance growths are observed through the beam transport lines between the injector linac and both rings. It is considered that some parts of them are due to coherent synchrotron radiation as the observed horizontal emittance blowups depend on the bunch charge. Especially for the HER injection, physical aperture around the injection point and ring dynamic aperture also contribute, as both are narrower than the design. In this paper, we discuss the injection issues up to 2022 operation and outlook for the future to maximum collision currents.
Paper: MOPL120
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL120
About: Received: 03 May 2023 — Revised: 08 Jun 2023 — Accepted: 08 Jun 2023 — Issue date: 26 Sep 2023
MOPL125
750 MHz IH-DTL for a proton therpy linac
844
750 MHz IH-DTL with the capability to accelerate protons from 3 to 10 MeV was proposed for the compact therpy linac that now under development in IMP. Four drift tube sections were housed in a single vacuum chamber and coupled with three large drift tubes which housing focusing triplet lens inside. In each drift tube section, there were 9 to 10 drift tubes, supported by the separated ridges. This cavity will be powered by a 1 MW klystron at 0.1% duty cycle, the kp factor is about 1.7 at the operation power level. The tank is now under construction and expected to be ready for beam commissioning in the middle of 2023. The overall cavity design and the status of the power cavity are presented in this paper.
Paper: MOPL125
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL125
About: Received: 02 May 2023 — Revised: 08 Jun 2023 — Accepted: 08 Jun 2023 — Issue date: 26 Sep 2023
MOPL127
Status and overview of the activities on ESS DTLs
851
The Drift Tube Linac (DTL) for the ESS Linac will accelerate H+ beams of up to 62.5 mA peak current from 3.62 to 90 MeV. The structure consists of five cavities. The first cavity (DTL1, 21 MeV) has been commissioned with beam in summer 2022. DTL2, 3 and 4 are installed in the tunnel since the end of 2022, ready for the conditioning and commissioning starting in 2023. DTL5 is under assembly and will be transported to the tunnel after the completion of beam commissioning up to 74 MeV. The paper wants to give an overview of the activities already done and ongoing on the five DTLs: from assembly to tuning, from conditioning to beam commissioning.
Paper: MOPL127
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL127
About: Received: 02 May 2023 — Revised: 09 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPL131
The Frascati DAFNE LINAC modulator upgrade
862
The Frascati linear accelerator was used as electron and positron source for the DAFNE collider and the Beam Test Facility (BTF) where the fixed target experiments as PADME or irradiation test for space components are ongoing. Builded in 1996 an upgrade of the L-C traditional resonant charging system is started in 2018 and today 3 of the 4 RF power stations modulator are upgraded from the 3-phase variable phase control (SCR) based on a full-wave bridge diode assembly to a new 2 constant-current capacitor charging power supplies. This paper will discuss the design of the upgrade and the performances of the systems in operation
Paper: MOPL131
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL131
About: Received: 03 May 2023 — Revised: 06 Jun 2023 — Accepted: 06 Jun 2023 — Issue date: 26 Sep 2023
MOPL139
High Power Radiofrequency Operation of the Radiofrequency Quadrupoles in the Spallation Neutron Source
869
The Spallation Neutron Source (SNS) recently took delivery of a third Radiofrequency Quadrupole (RFQ03) that will ultimately be installed on the front-end (FE) of the SNS Linac. The first RFQ (RFQ01) operated in the SNS FE for more than a decade before being replaced with the second RFQ (RFQ02). RFQ01 was relocated to the Beam Test Facility (BTF) where it operated for five more years. The RFQ02 was initially installed in the BTF for high power testing and used with H- beam for BTF operation. It replaced RFQ01 in the SNS FE in 2017 and has been operating for beam production since then. There are some differences between the three RFQs. RFQ01 has a square cross-section with pi-mode stabilizing loops (PISLs) with the structure being fabricated using two layers of materials, GlidCop outside and OFHC inside. RFQ02 and RFQ03 has an octagonal cross-section with end-wall stabilizer rods and was fabricated using OFHC only. RFQ01 suffered some field flatness distortion incidents that resulted in degradation in beam transmission efficiency and required RF tuning. RFQ02 has performed well but had a melted RF seal in the high energy end wall, that was ultimately mitigated by a redesign of the end flange seals. The SNS decided to order RFQ03 that has a design that followed that of RFQ02 closely, but end-wall contacts were modified to prevent RF seal failure. This report presents the testing, installation, high power RF operation, and design improvements of the RFQ03.
Paper: MOPL139
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL139
About: Received: 01 May 2023 — Revised: 08 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
MOPL140
Design and fabrication of the waveguide Iris couplers for the Spallation Neutron Source drift tube linac
873
The Spallation Neutron Source (SNS) employs six cavities in the Drift Tube Linac (DTL) section to accelerate the H- ion beam to 87MeV. Each cavity is energized by a 2.5MW peak power klystron at 402.5MHz using rapid tapered waveguide iris couplers. All six original iris couplers have been in operation without replacement for over two decades. The increased RF power demands of the Proton Power Upgrade (PPU) project and operational problems, including arcing, temperature excursions, and vacuum bursts, have prompted the development of new iris coupler spares. The original iris couplers were made of GlidCop material, which is known to be mechanically strong and thermally stable, but is porous, expensive, and difficult to use in fabrication. To overcome these problems, the new spare couplers use Oxygen-Free Copper (OFC) and stainless steel (SS). This paper will discuss the mechanical, thermal and RF design, as well as challenges in the final coupler fabrication.
Paper: MOPL140
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL140
About: Received: 19 Apr 2023 — Revised: 08 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
MOPL144
Steering to a wakefield reduced trajectory using RF kick data in the SLAC linac
880
Wakefields kick the electron bunch to a non-linear tilt causing emittance growth. Any additional correlation like an energy chirp (energy vs z dependence) will filament the disturbance further causing a nearly unrecoverable bigger emittance. For C3 (Cool Copper Collider) the emittance preservation numbers seems to be about 1000 times more stringent than achieved. It is actually "only" about 30 times trickier (square root of 1000) which is still a big number. During two-bunch setups for LCLS (Linac Coherent Light Source) it was observed that the same transverse beam offset reduced the wakefield kick and at the same time the RF kick from the most probably misaligned accelerating structure. To turn this around an RF kick can be easily measured with RF on and off, or a phase scan using a single bunch. The plan is to test this at FACET-II where the emittance growth is quite high due to a high charge. Experimental results where RF kicks are locally minimized and therefore give a better starting value for emittance tuning will be presented in a later paper.
Paper: MOPL144
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL144
About: Received: 02 May 2023 — Revised: 11 May 2023 — Accepted: 23 Jun 2023 — Issue date: 26 Sep 2023
MOPL180
Proton and electron RLA optics design
958
We describe optics designs of the key components of proton and electron Recirculating Linear Accelerators (RLAs). They are presented in the context of a high-power hadron accelerator being considered at ORNL and a CEBAF electron energy doubling study, FFA@CEBAF, being developed at Jefferson Lab. Both concepts rely on the Fixed-Field Alternating gradient (FFA) arc optics designs where multiple beam passes are transported by a single beam line.
Paper: MOPL180
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL180
About: Received: 13 May 2023 — Revised: 16 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
MOPL182
CEBAF 22 GeV FFA energy upgrade
962
Extending the energy reach of CEBAF by increasing the number of recirculations, while using the existing linacs is explored. This energy upgrade is based on the multi-pass acceleration of electrons in a single non-scaling Fixed Field Alternating Gradient (FFA) beam line, using Halbach-style permanent magnets. Encouraged by the recent successful demonstration of CBETA, a proposal was formulated to nearly double the energy of CEBAF from 12 to 22~GeV by replacing the highest energy arcs with FFA transport. The new FFA arcs would support simultaneous transport of an additional 6 passes spanning roughly a factor of two in energy. One of the challenges of the multi-pass (11) linac optics is to assure uniform focusing over a wide range of energies. Here, we propose a triplet lattice that provides a stable periodic solution covering an energy ratio of 1:33. The current CEBAF injection at 123 MeV, makes optical matching in the first linac impossible due to the extremely high energy ratio (1:175). Replacement of the current injector with a 650 MeV recirculating injector will alleviate this issue. Orbital and optical matching from the FFA arcs to the linacs is implemented as a compact non-adiabatic insert. The design presented here is anticipated to deliver a 22 GeV beam with normalized emittance of 76 mm·mrad and a relative energy spread of 1×10^{-3}. Further recirculation beyond 22 GeV is limited by the large (974 MeV per electron) energy loss due to synchrotron radiation.
Paper: MOPL182
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL182
About: Received: 03 May 2023 — Revised: 08 May 2023 — Accepted: 12 May 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
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
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
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
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
TUODA3
New techniques for the LNL superconductive linac ALPI beam dynamics simulations and commissioning
1307
The superconductive quarter wave cavities hadron Linac ALPI is the final acceleration stage at the Legnaro National Laboratories. It can accelerate heavy ions from carbon to uranium up to 10 MeV/u for nuclear and applied physics experiments. It is also planned to use it for re-acceleration of the radioactive ion beams for the SPES (Selective Production of Exotic Species) project. The linac was designed in 90’ with the available techniques and it was one of the peak technologies of this kind in Europe at those times. However, the improvements on the cavity fields increased the real-estate gain and the energy output, at the price of lattice periodicity and non-linear RF defocusing. This fact turned out to be troublesome for the operations and delayed the nominal transmission achievement. In this paper we will present the innovative results obtained with swarm intelligence algorithms, in simulations and commissioning. In particular, the increment of the longitudinal acceptance for RIB (Radioactive Ion Beams) acceleration, managing 84 independent cavity phases, and beam orbit correction without the beam first order measurements will be discussed.
Paper: TUODA3
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUODA3
About: Received: 03 May 2023 — Revised: 20 Jun 2023 — Accepted: 20 Jun 2023 — Issue date: 26 Sep 2023
TUODC2
Fabrication, conditioning, installation and commissioning with the beam of the first High Gradient (HG) module for the FERMI linac upgrade
1347
FERMI is the seeded Free Electron Laser (FEL) user facility at Elettra laboratory in Trieste, operating in the VUV to soft X-rays spectral range. In order to extend the FEL spectral range to shorter wavelengths, an upgrade plan for increasing the Linac energy from 1.5 GeV to 2.0 GeV is actually going on. After the successful testing of the short prototype of the new high gradient (HG) S-band accelerating structure up to an accelerating gradient of 40 MV/m, two full-length 3.0 m HG structures have been built and installed at the FERMI linac. In this paper, we report the low power measurement, conditioning results, and commissioning with the beam of the first HG module.
Paper: TUODC2
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUODC2
About: Received: 28 Apr 2023 — Revised: 05 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
TUPA006
Activities at INFN LASA on ESS Medium Beta Cavities
1362
To complete the Italian In-Kind contribution to the ESS SRF Linac, we are working on the qualification of the last eight missing cavities. To achieve this, we are proceeding with reprocessing of not yet qualified cavities and, as a mitigation, we are constructing at the vendor four more cavities. In this paper, we report on the actual status of both of these activities with the most recent results.
Paper: TUPA006
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA006
About: Received: 03 May 2023 — Revised: 07 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
TUPA120
Fabrication progress of the prototype spoke cavity for the JAEA-ADS linac
1588
The Japan Atomic Energy Agency (JAEA) has been proposing an accelerator-driven system (ADS) as a future nuclear system to efficiently reduce high-level radioactive waste generated in nuclear power plants. As a first step toward the full-scale design of the CW proton linac for the JAEA-ADS, we are now prototyping a low-beta (around 0.2) single-spoke cavity. The actual cavity fabrication started in 2020. Most of the cavity parts were shaped in fiscal year 2020 by press-forming and machining. In 2021, we started welding the shaped cavity parts together. By preliminarily investigating the optimum welding conditions using mock-up test pieces, each cavity part was joined with a smooth welding bead. So far, we have fabricated the body section and the beam port section of the cavity. By measuring the resonant frequency of the temporarily assembled cavity, we have confirmed that there is no significant problem with the cavity fabrication. In this paper, fabrication progress of the prototype spoke cavity is presented.
Paper: TUPA120
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA120
About: Received: 02 May 2023 — Revised: 10 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
TUPA121
Design and optimization of a proton source extraction system for the JAEA-ADS linac
1591
The Japan Atomic Energy Agency (JAEA) is designing a 30 MW continuous wave (cw) superconducting proton linear accelerator (linac) for the Accelerator Driven Subcritical System (ADS) proposal. The JAEA-ADS linac's source must provide a proton beam over 20 mA with an energy of 35 keV and a normalized rms emittance of less than 0.1 π mm mrad. As the extraction system determines the beam properties and quality, systematic optimizations in the geometry and input values of the extraction system design were conducted using the AXCEL-INP 2-D simulation program to satisfy the goal requirements. This work describes the extraction system design and reports the beam dynamics results of the first study for the proton source of the JAEA-ADS linac.
Paper: TUPA121
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA121
About: Received: 27 Apr 2023 — Revised: 09 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
TUPA170
Thermal and deformation analysis of a 750 MHz IH-DTL prototype for medical applications
1695
This article presents an IH-DTL prototype, capable of accelerating carbon ion beams from 5 MeV/u to 5.5 MeV/u, for manufacturing and assembling validation in a hadrontherapy linac injector. A multi-physics study is made in CST Studio concerning steady-state thermal, stress and deformation analysis. Convenient water-cooling circuits close to drift tubes are simulated to evaluate field errors and frequency detuning as they can affect directly to beam dynamics.
Paper: TUPA170
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA170
About: Received: 03 May 2023 — Revised: 09 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
TUPA171
H11(0) end cells for a 750 MHz IH structure
1699
This article presents a study on the H11(0) end cell of an IH-DTL prototype for accelerating carbon ion beams from 5 to 5.5 MeV/u, which is designed for a hadron therapy linac injector. The voltage across the first and last gap in a drift tube linac tends to drop from a typical uniform voltage distribution along the inner cells. In the case of an IH cavity, the power cost to supply the necessary RF energy in this region is affected by the dimensions of the end cell and gap, as well as the girder undercut. The end cells were modeled in CST Microwave Studio for an appropriate power loss optimization of the most relevant dimensions. The same model also introduced dipole correction based on slanted faces, and transverse fields were analyzed.
Paper: TUPA171
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA171
About: Received: 03 May 2023 — Revised: 11 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
TUPA172
SARAF beam commissioning results: injector, MEBT
1703
IAEC/SNRC (Israel) is constructing an accelerator facility, SARAF, for neutron production. It is based on a linac accelerating 5 mA CW deuteron and proton beam up to 40 MeV. As a first phase, IAEC constructed and operated a linac (SARAF Phase I), from which remains an ECR ion source, a Low-Energy Beam Transport (LEBT) line and a 4-rod RFQ. Since 2015, IAEC and CEA (France) are collaborating in the second phase, consisting in manufacturing of the linac. The injector control-system has been recently updated and the Medium Energy Beam Transport (MEBT) line has been installed and integrated to the infrastructure. It has been fully commissioned during the first semester of 2023 for proton and deuteron beams. This paper presents the results of the integration, tests and commissioning of the injector and MEBT.
Paper: TUPA172
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA172
About: Received: 02 May 2023 — Revised: 06 Jun 2023 — Accepted: 06 Jun 2023 — Issue date: 26 Sep 2023
TUPA175
Injector and synchrotron commissioning of helium ion beams at the MedAustron Ion Therapy Center
1713
MedAustron is a synchrotron-based ion cancer therapy facility located in Austria. Patients are treated with proton and carbon ion beams in an energy range of 62-252 MeV and 120-402 MeV/u, respectively. The facility features three clinical irradiation rooms, among which horizontal and vertical beam lines as well as a proton gantry are available for treatment. A fourth irradiation room is dedicated to non-clinical research. In 2021, a development project started, which aims at commissioning helium ion ($\mathrm{^{4}He^{2+}}$) beam up to the non-clinical irradiation room. A first major milestone was reached by completing the commissioning of helium in the ECR ion source branch, the LEBT and the LINAC section, where the beam is accelerated up to 7 MeV/u. In this work we discuss the challenges and main results achieved during the injector commissioning (i.e. emittance, intensity and transmission efficiency). Furthermore, recent outcomes from the injection of $\mathrm{^{4}He^{2+}}$ beam into the synchrotron as well as acceleration and extraction results are presented.
Paper: TUPA175
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA175
About: Received: 02 May 2023 — Revised: 10 May 2023 — Accepted: 22 Jun 2023 — Issue date: 26 Sep 2023
TUPA176
Alvarez drift tube linac for medical applications in the framework of HITRIplus project
1717
A first beam dynamics and RF design of an Alvarez-type drift tube linac (DTL) has been defined in the framework of the EU project, HITRIplus. Its main application is to be exploited as a carbon (12C4+) and helium (4He2+) ion injector into a compact synchrotron for patient treatment. As a second implementation, helium particle acceleration with a higher duty cycle of 10% enables the possibility for radioisotope production. The 352.2 MHz structure efficiently accelerates two ion species, for A/q=3 and 2, in the energy range of 1÷5 MeV/u and for a beam current of ~0.5 mA. The design extends to a full length of ~7 meters. Permanent magnet quadrupoles are utilized all along the DTL for focusing both ion beams. This paper presents a first-phase analysis towards a realistic DTL design capable of providing full beam transmission and minimum overall emittance increase for two ion beams.
Paper: TUPA176
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA176
About: Received: 08 May 2023 — Revised: 08 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
TUPA177
Comparison of 352 MHz LINAC structures for injection into an ion therapy accelerator
1721
In the frame of ongoing initiatives for the design of a new generation of synchrotron-based accelerators for cancer therapy with ion beams, an analysis of linac designs has been started, to address a critical element with strong impact on performance and cost of the accelerator. The goal is to identify alternatives at lower cost and similar or possibly smaller footprint than the standard 217 MHz injector presently used in all carbon therapy facilities in Europe. As an additional feature, a new linac design can be tailored to produce radioisotopes for treatment and diagnostics in parallel with operation as synchrotron injector. In this paper is analysed the attractive option of moving to 352 MHz frequency, to profit of reliable mechanical designs already developed for protons and of the cost savings that can be obtained using as RF power sources klystrons with a much lower cost per Watt than tubes or solid-state units. The paper will present a Quasi-Alvarez Drift Tube Linac (DTL) version of an injector linac for carbon ions at q/m=1/3 and compare it with recently developed DTL and IH designs. The option of a separated-IH type linac will be also discussed, together with a standard IH design at 352 MHz. Finally, a DTL design at 352 MHz for injection of fully stripped helium ions into the synchrotron will be presented.
Paper: TUPA177
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA177
About: Received: 09 May 2023 — Revised: 09 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
TUPA178
Status of the ESS normal conducting linac including beam commissioning to DTL4
1725
The European Spallation Source (ESS) aims to build and commission a 2 MW proton linac ready for neutron production in 2025. Commissioning of the normal conducting section of the linac is underway and previous papers have reported the performance of the microwave-discharge ion source, Radio Frequency Quadrupole (RFQ) and first Drift Tube Linac (DTL) tank. This paper describes the recent assembly, installation, testing and commissioning of an additional threee DTL tanks as well as developments of supporting systems such as RF feedback, control system tools and operating procedures.
Paper: TUPA178
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA178
About: Received: 03 May 2023 — Revised: 08 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
TUPA180
Accelerator and beam physics challenges in support of FRIB experiments
1729
The Facility for Rare Isotope Beams (FRIB), a major nuclear physics facility for research with fast, stopped, and reaccelerated rare isotope beams, started operation in May 2022. Since then, five nuclear physics experiments have been successfully accomplished. The experiments with rare isotope beams typically last within 1-2 weeks. Each experiment requires a different primary beam and its energy. It is critical to shortening the accelerator and fragment separator setup time to meet the requirements of the FRIB Users community. Currently, the primary focus in the linac is to reduce the accelerator setup time and ramp up beam power. Many physics applications, including Machine Learning, have been developed and used to set up the accelerator and beamlines. The simultaneous acceleration of multiple charge states of heavy ion beams is routinely used to minimize the beam power deposition on the charge selector slits after the stripper. The challenges in the fragment separator are related to the highly non-linear beam physics due to the large emittance and momentum spread of the isotope beams. Since the iron-dominated SC magnets operate near saturation, the optimization process includes field distributions at different excitation currents. This paper discusses the theoretical and experimental procedures to improve the linac and fragment separator performance.
Paper: TUPA180
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA180
About: Received: 28 Apr 2023 — Revised: 12 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
TUPA181
Linear accelerator for a next generation rare isotope facility
1733
We propose a linear accelerator concept for a Next Generation Nuclear Physics Accelerator Facility - a versatile User Facility with a wide variety and high availability of its instruments and beam time. The concept is based on the simultaneous acceleration of light and heavy ion primary beams. It improves the utilization of the superconducting driver-accelerator capabilities and allows for the simultaneous and complementary rare isotope production in two different targets, namely a thin target for fragmentation of accelerated heavy ion beams, and a thick spallation target for an isotope separation on-line (ISOL) system driven by light ion beams. This approach supports the multi-user operation of the facility, and enables other research driven by light ion beams. The concept is presented as an upgrade of the Facility for Rare Isotope Beams (FRIB, MSU) with a 60-MV compact room-temperature continuous-wave light ion injector. The funneling of the light and heavy ion beams as well as their distribution to production targets is discussed.
Paper: TUPA181
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA181
About: Received: 27 Apr 2023 — Revised: 08 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
TUPA186
Advanced basic layout of the Helmholtz LInear Accelerator for cw heavy ion beams at GSI
1747
The design and construction of continuous wave (cw) superconducting (sc) high intensity linacs is a crucial goal of worldwide accelerator technology development. The standalone sc cw heavy ion HElmholtz LInear ACcelerator (HELIAC) is a common project of GSI Helmholtz Centre for Heavy Ion Research and Helmholtz Institute Mainz (HIM) under key support of Goethe University Frankfurt (IAP). In 2017 the first section of the linac has been successfully commissioned and extensively tested with heavy ion beam at GSI, featuring the capability of 216.816 MHz multi-gap Crossbar H-mode (CH) DTL-structures. At present, the first fully equipped cryomodule of the HELIAC is under construction. Six further superconducting CH cavities are being procured. The HELIAC beam dynamics concept foresees a total of twelve CH-cavities in order to accelerate ions with a mass-to-charge ratio of 6 up to a smoothly variable energy in the range 3.5 - 7.5 MeV/u. In this paper, an advanced compact and less complex layout is presented, where the same number of accelerating cavities can be accommodated in three instead of four cryomodules, thus also reducing the number of solenoids and rebunchers, required for beam focusing. In addition, the integration and linking of the HELIAC to the GSI accelerator facility will be outlined.
Paper: TUPA186
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA186
About: Received: 25 Apr 2023 — Revised: 10 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
TUPA189
Operation of copper cavities at cryogenic temperatures
1754
This work is focused on the anomalous skin effect in copper and how it affects the efficiency of copper-cavities in the temperature range 40-50 K. The quality factor Q of three coaxial cavities was measured over the temperature range from 10 K to room temperature in the experiment. The three coaxial cavities have the same structure, but different lengths, which correspond to resonant frequencies: around 100 MHz, 220 MHz and 340 MHz. Furthermore, the effects of copper-plating and additional baking in the vacuum oven on the quality factor Q are studied in the experiment. A “geometric model” based on a spherical Fermi - surface and using the equivalent skin layer model is presented in the paper to calculate the surface resistance which is relevant for the RF power losses in the cavity walls. Finally, Cavity cooling process about the pulsed heat transport from the surface into the bulk copper is simulated. The motivation is to check the feasibility of an efficient, pulsed, ion linac, operated at cryogenic temperatures.
Paper: TUPA189
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA189
About: Received: 02 May 2023 — Revised: 23 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
TUPA190
The double drift harmonic buncher (DDHB) and acceptance investigations at linac and cyclotron injections
1758
Particle accelerators demand high particle transmission and reduced longitudinal emittance; hence, effective bunching systems are requested. The concept based on an efficient, compact design called “Double Drift Harmonic Buncher - DDHB” fulfills these two requirements for a c.w. or pulsed beam injection into an RFQ, a DTL, or a cyclotron. The proposal is associated with two buncher cavities separated by a drift space and an additional drift at the end of the system for a longitudinal beam focus at the entrance of the next accelerator unit, whose candidates can be one of those mentioned above. The investigations are focused on exploring accurate acceptance rates. To obtain successful and understandable outputs from the DDHB concept, a new multi-particle tracking beam dynamics code called “Bunch Creation from a DC beam - BCDC” has been developed for detailed investigations of space charge effects. It allows to calculate the transformation of intense dc beams into particle bunches in detail with a selectable degree of space charge compensation at every location. This paper presents the results from various investigations with and without space charge effects.
Paper: TUPA190
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA190
About: Received: 03 May 2023 — Revised: 04 Jun 2023 — Accepted: 21 Jun 2023 — Issue date: 26 Sep 2023
TUPA192
Strategies for SPIRAL2 linac heavy-ion beam tuning
1762
Heavy ions have been accelerated for the first time by SPIRAL2 in 2022. A fast method to tune the linac cavities has been used (< 1 hour by now, < 10’ in the future) to obtain a 7 MeV/A 18O6+ beam (50 microA CW). Then an automatic Q/M beam change procedure has been successfully used to directly produce a 18O7+ beam. The goal was to demonstrate the possibility to tune a beam even if its intensity is too low (<10 microA) to be seen by phasemeters (BPM) along the linac. The linac transmission was ~ 100% for both beams and, as expected, the measured output energy was the same. The same oxygen reference beam tuning has been also used to obtain 80 microA of 40Ar14+ at 7 MeV/A. Again, the same method has been used to tune the linac cavities at the RFQ output energy beam (0.73 MeV/A, no acceleration). These different methods and the one used to tune the linac output energy are presented.
Paper: TUPA192
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA192
About: Received: 03 May 2023 — Revised: 06 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
TUPA193
NEWGAIN project at GANIL-SPIRAL2 : design of the new heavy ion injector for the superconducting linac
1765
A new project, NEWGAIN (NEW GAnil Injector), is under development at GANIL, and aims to build a second injector for heavier beams with A/q up to 7, as an extension of the SPIRAL2 accelerator. With this upgrade, SPIRAL2 will provide high intensity beams, from proton to uranium, thus increasing GANIL international competitiveness both in fundamental science and associated applications. This paper presents the layout and describes the main technical components of the new injector, based on 2 ECR ion sources (one of them existing), two LEBT, one RFQ and a MEBT section to transport the beam into the present MEBT connected to the LINAC.
Paper: TUPA193
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA193
About: Received: 03 May 2023 — Revised: 10 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
TUPA194
RF-acceleration studies for the HBS-linac applying alternating phase focusing concepts
1768
The recent layout of the Jülich High Brilliance Neutron Source (HBS) driver linac is based on short crossbar H-mode (CH) cavities operated at a fixed synchronous phase. In the last decades the computing power for the development of linacs, available to physicists and engineers, has been increased drastically. This also enabled the accelerator community to finally carry out the required R&D to generate further the idea of drift tube linacs with alternating phase focusing (APF) beam dynamics, originally proposed in the 1950s. This focusing method uses the electric fields in between the drift tubes (i.e., gaps) to provide subsequent transverse and longitudinal focusing to the beam along multiple gaps. The beam focusing properties within each gap are adjusted individually by means of the synchronous phase. As a result of the alternating phase focusing method, these linacs can operate completely without internal magnetic lenses. The R&D-program for the high brilliance neutron source HBS offered the opportunity to investigate the APF concept further in order to open this advanced concept for high duty-factor, high intensity hadron beam acceleration. Besides, a prototype APF-interdigital H-mode (IH)-cavity has been designed and is going to be build and tested in the next future.
Paper: TUPA194
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPA194
About: Received: 27 Apr 2023 — Revised: 12 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
TUPL022
Recommissioning of the FLASH injector and linac
1816
FLASH, the <strong>F</strong>ree electron <strong>LAS</strong>er in <strong>H</strong>amburg is currently undergoing a substantial refurbishment and upgrade project (FLASH2020+). A major stage was the 9 month shutdown in 2021/22. During this shutdown key components of the injector/linac where inserted, moved, rebuild or upgraded to enable the efficient and reliable preparation of electron bunches for HGHG and EEHG seeding in the FLASH1 beamline and simultaneous SASE operation in the FLASH2 beamline. In particular we have, added a new injector laser system, installed a laser heater system, moved the 1st bunch compression chicane downstream to generate space for the laser heater, replaced two old acceleration modules with modern high-gradient modules (thereby gained an additional 100 MeV of energy), replaced the 2nd bunch compression chicane with a more fancy movable one that enables variable longitudinal dispersion while allowing the compensation of bunch tilts, and saves space for an additional matching section section at the entrance to the main linac. Here we describe the more general aspects of the re-commissioning of the machine with beam which started early October 2022.
Paper: TUPL022
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL022
About: Received: 02 May 2023 — Revised: 08 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
TUPL048
FERMI status and perspectives
1860
We present an overview of the FERMI seeded free electron laser (FEL) facility located at the Elettra laboratory in Trieste, Italy. FERMI, in operation with both FEL lines FEL-1 and FEL-2 since 2012, covers the spectral range between 100 nm and 4 nm with light characterized by variable polarization, narrow spectral width, stable intensity and central wavelength. A series of infrastructure upgrades have been proposed in recent years to keep the facility in a world-leading position. The upgrade includes profound modifications of the linac and the two FERMI FELs with the ambition to extend the performance of the FEL and the control of the light produced to include the K edges of N and O and the L edges of transition metals. Recently, new accelerating section allowed an increase of the beam energy of about 100 MeV and the configuration of the first FEL-1 has been revamped. The FEL has been changed into an echo-enabled harmonic-generating FEL, and commissioning of this new FEL is underway.
Paper: TUPL048
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL048
About: Received: 03 May 2023 — Revised: 26 Jun 2023 — Accepted: 26 Jun 2023 — Issue date: 26 Sep 2023
TUPL055
Properties of superradiant spontaneous THz undulator radiation by an RF compressed electron beam
1877
Velocity bunching, sometimes called rectilinear rf bunch compression, is a common technique to generate femtosecond MeV electron bunches from a photoinjector system. Such ultrashort beam can be used to generate coherent THz radiations, in particular, coherent undulator radiation (CUR). However, beam properties such as beamsize, transverse emittance, bunch length and energy spread after bunch compression have significant effects on angular and spectral distributions of CUR. In this study, we perform space charge tracking of electron beam in the NSRRC photoinjector when its booster linac being operated near zero crossing phase in rf bunch compression and the resultant electron distribution of the output beam is then used for calculation of incoherent and coherent undulator radiation from a 10-cm period planar undulator by an algorithm based on Lienard-Wiechart potential. We also compared the radiation properties for cases of multiple bunch and single bunch operation with the same total charge.
Paper: TUPL055
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL055
About: Received: 02 May 2023 — Revised: 09 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
TUPL056
Simulation study of a planar dielectric-lined waveguide structure for manipulation of femtosecond high brightness electron beam in longitudinal phase space
1881
In many advanced accelerator facilities such as e+e--linear colliders and high gain free electron lasers, magnetic bunch compressors are often used for enhancement of beam brightness. However, the energy chirp (correlated energy spread) introduced into the beam by the chirper linac remained after bunch compression is undesirable in some applications. In this report, we present our study of a planar dielectric-lined waveguide (DLW) structure that can be used to remove the remaining energy chirp after bunch compression. As revealed from ELEGANT simulation of the high brightness driver linac system, a residual energy chirp of about 42 keV/ m is left after bunch compression. We successfully used a 1-m long corrugated pipe dechirper to remove the residual energy chirp in ELEGANT simulation. However, fabrication of this 1-m long corrugated pipe structure is not an easy task. In order to save space, we consider to use planar DLW structures to remove residual energy chirp after bunch compression instead. Wake potential due to this DLW dechirper has been calculated by CST code. An optimized geometry will be presented in this report. Wake potential as calculated form CST code is de-convoluted to obtain a wake function. The effect of the dechirper on beam distribution can be studied by particle tracking using this wake function in ELEGANT. We expect the performance of the DLW dechirper will be equivalent to the 1-m long corrugated pipe dechirper but with a much more compact size.
Paper: TUPL056
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL056
About: Received: 02 May 2023 — Revised: 11 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
TUPL059
Study of an ERL-based X-ray FEL
1893
An energy-recovery-linac (ERL)-based X-ray free-electron laser (FEL) is proposed considering its three main advantages: i) shortening the linac by recirculating the electron beam by high-gradient SRF cavities, ii) saving the klystron power and reducing the beam dump power through the energy recovery in the SRFs, iii) producing a high average photon brightness with high average beam current. Such a concept has the capability of optimized high-brightness CW X-ray FEL performance at different energies with simultaneous multipole sources. In this paper, we will present the preliminary results on the optics design, parameter optimization, beam dynamics study and identification of potential R&D aspects.
Paper: TUPL059
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL059
About: Received: 01 May 2023 — Revised: 08 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
TUPL100
HPC modelling of a high-gradient C-Band LINAC for applications including hard X-Ray FREE-Electron Lasers
1958
The production of soft to hard x-rays (up to 25 keV) at XFEL (x-ray free-electron laser) facilities has enabled new developments in a host of disciplines. However, there is great potential for new scientific discovery at even higher energies (42+ keV), such as those provided by MaRIE (Matter-Radiation Interactions in Extremes) at Los Alamos National Laboratory. These instruments can require a large amount of real estate, which quickly escalates costs: The driver of the FEL is typically an electron beam linear accelerator (LINAC) and the need for higher electron beam energies capable of generating higher energy X-rays can dictate that the LINAC becomes longer. State of art accelerating technology is required to reduce the LINAC length by reducing the size of the cavities, which in turn provides for a high gradient of acceleration. Compact accelerating structures are also high-frequency (S, C, and X-bands). Here, we describe using the Argonne Leadership Computing Facility (ALCF) ), located at Argonne National Laboratory to facilitate our investigations into design concepts for future XFEL high-gradient LINAC's in the C-band (~4-8 GHz). We investigate a Disk Loaded Wave Guide (DLWG) and an elliptical traveling wave (TW) structure modeled for operation at f =5.712 GHz at the ALCF using VSim software. We used an existing account under the ALCF LIGHTCONTROL project.
Paper: TUPL100
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL100
About: Received: 07 May 2023 — Revised: 12 Jun 2023 — Accepted: 12 Jun 2023 — Issue date: 26 Sep 2023
TUPL101
Preliminary design on the accelerator of an infrared free electron laser oscillator
1961
We are building a new infrared Free Electron Laser (FEL) facility in China that will produce infrared laser covering the spectral range from 2.5 um to 200 um. It is made up of two oscillators generating middle infrared and far infrared laser respectively, which are driven by a single RF linear accelerator (linac) with a tunable beam energy from 12 MeV to 60 MeV. According to the requirement of the FEL physics, the linac is designed with an rms energy spread of less than 0.5%, a transverse rms emittance of less than 40 mm-mrad and a micro bunch length of 4-10 ps with a charge of 1 nC inside. In this manuscript, we present the preliminary design of the accelerator, from the electron gun through the transport line's terminus.
Paper: TUPL101
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL101
About: Received: 02 May 2023 — Revised: 16 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
TUPL108
Design of a new S-band 250 MeV electron linac with RF SLED compression for the CLS
1981
RI Research Instruments (RI) in partnership with The Canadian Light Source (CLS) have designed a new 250 MeV electron linac to inject into the 0.25-2.9 GeV booster synchrotron. The RF frequency is 3000.24 MHz, the sixth harmonic of the 500.04 MHz booster and storage ring RF cavity frequency, and the main accelerating sections consists of three 5 m constant gradient accelerating structures. The 3 GHz bunching sections and the first accelerating structure are fed by a 40 MW klystron, while structures two and three are fed by a single 40 MW klystron with a SLED RF compression scheme. The electron source consists of a 90 keV thermionic cathode with a 500 MHz modulated grid and a 500 MHz sub-harmonic pre-buncher to synchronise with the booster ring cavity frequency. A single-bunch mode can be delivered, as well as a multi-bunch with up to 140 ns bunch trains of up to 5.6 nC of charge per shot, both at a 1 Hz repetition rate to match the booster ramp cycle. The project is scheduled to bring the linac into operation for top-up injection into the CLS storage ring by mid-2024. This paper will present the design with a special focus on the implementation of a SLED to deliver a recovery mode of operation using only a single klystron.
Paper: TUPL108
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL108
About: Received: 03 May 2023 — Revised: 05 Jun 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
TUPL109
Simulation study towards a new injector LINAC for the SOLARIS synchrotron facility
1985
SOLARIS injector LINAC is designed to efficiently fill the electron storage ring. The injection currently takes place at 540 MeV, two times per day. After the accumulation of electron current, the energy is ramped up inside the ring to 1.5 GeV via two active RF cavities. Top-up injection would be of extreme benefits for user operation, therefore here we present a simulation study for the design of a new injector that would make this possible in the future. The major constraint for the simulation campaigns has been the space available in the existing LINAC tunnel. The idea is to replace the current machine (or modifying it) without infrastructural interventions in terms of tunnel expansion. Performed studies demonstrate that the best solution is provided by a Hybrid S-band/C-band LINAC. Simulations have been performed using different codes and results are shown here. Finally, a new machine working at 1.5 GeV would also pave the way to further diagnostic and/or experimental beamlines for particles and radiation solely based on the LINAC. In particular, one of the main goals is to achieve bunch compression below the picosecond level and low-emittance beams for a future short-pulse facility or a Free Electron Laser.
Paper: TUPL109
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL109
About: Received: 31 Mar 2023 — Revised: 05 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
TUPL111
Start-to-end simulation of the full energy linac injector for the Southern Advanced Photon Source
1992
Southern Advanced Photon Source (SAPS) is a 3.5 GeV diffraction limited storage ring, being planned to be built near the site of the China Spallation Neutron Source (CSNS). Full energy Linac injector reserves the possibility of using the Linac for free electron laser application in a future upgrade. In this paper, the start-to-end simulation of the full energy Linac working on the ring injection mode are given.
Paper: TUPL111
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL111
About: Received: 03 May 2023 — Revised: 06 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
TUPL123
Flexi-Gun research and development project at BESSY II
2013
A research project was initiated at HZB to develop a new E-Gun control system for the Linac Gun to realize the advanced demands from the BESSY II injection scheme. The Flexi-Gun system will allow significantly higher flexibility in both pulse load and pulse timing structure. The purpose built gun test stand is equipped with a diagnostic beamline. Developed and manufactured in-house, the potential for knowledge transfer has led to a collaboration with ALBA for start-to-end particle tracking simulations. This article presents the motivation and potential of the Flexi-Gun, the development of the driver board and control, and the first measurements of the beam parameters. With the "Flexi-Gun" project, the upgraded Linac E-Gun becomes the optimal injector for BESSY II.
Paper: TUPL123
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL123
About: Received: 28 Apr 2023 — Revised: 12 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
TUPL125
Physical design of a 10 MeV electron linac for industrial application and material irradiation effect research
2020
A 35MeV/2 mA S-band electron linear accelerator used to interact with solid targets to generate neutrons, gamma rays, and X-rays has been proposed to provide a scientific research platform for nuclear energy development, material development, biomedicine, deep space exploration besides other industrial applications. The accelerator has a three-stage accelerating structure, after the first-stage of structure, the beam energy can reach 10MeV, and then completes 270° vertical bend and 45° horizontal bend, respectively, for industrial applications and material irradiation effect research. This paper presents the first-stage acceleration of the linac and its bend branch, including a pre-buncher, an acceleration structure (provides beam energy 10MeV and average current 2mA), 270° and 45° bend magnets, with beam loss rate less than 15%. A detailed physical design and dynamics simulation results are presented and discussed.
Paper: TUPL125
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL125
About: Received: 02 Apr 2023 — Revised: 11 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
TUPL126
Beam commissioning of the HEPS Linac
2023
The High Energy Photon Source (HEPS) is a synchrotron radiation source of ultrahigh brightness being built in China. Its accelerator complex is composed of a 6-GeV storage ring, a full energy booster, a 500-MeV Linac, and three transfer lines. The Linac is an S-band normal conducting electron linear accelerator with available bunch charge from 0.5 nC up to about 10 nC. The Linac installation was completed in July 2022 and high-power RF conditioning was finished in September 2022. Physics quantity based high-level applications have been developed for the HEPS Linac using our own platform Pyapas. The beam commissioning of the Linac is scheduled from December 2022 to March 2023. Detailed beam commissioning experiences and results of the HEPS Linac will be presented in this paper.
Paper: TUPL126
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL126
About: Received: 02 May 2023 — Revised: 16 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
TUPL129
Delivery status of the magnet system for the STAR high energy linac
2030
The Southern European Thomson back-scattering source for Applied Research (STAR) project, based on a collaboration among University of Calabria (UniCal), CNISM, INFN and Sincrotrone Trieste, has the goal to install and test at UniCal a short linear accelerator for high brightness electron beams that will drive a unique advanced X-ray Thomson source. In 2021 INFN was committed to install, test and commission an upgrade of the STAR Linac (STAR High Energy Linac) aiming to increase the X-ray beams energy from 30 keV up to 140 KeV. The new layout foreseen an increase of the electron beam energy from 65 MeV up to 150 MeV by the installation of two additional C-band acceleration cavities and an additional transfer-line where the high energy beam could be delivered to a second interaction point with the laser. The whole machine layout foreseen 43 warm electromagnets (solenoids, dipoles, quadrupoles and steerers) powered by 59 DC power supplies that will cover a wide power range from 90W up to 15 kW. In this paper, an overview of the magnet system is given together with the performed tests, the deliveries status and the future steps needed to finalize the complete machine installation.
Paper: TUPL129
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL129
About: Received: 03 May 2023 — Revised: 10 May 2023 — Accepted: 22 Jun 2023 — Issue date: 26 Sep 2023
TUPL130
Electron beam analysis and sensitivity studies for the EuPRAXIA@SPARC_LAB RF injector
2034
The interest in plasma-based accelerators as drivers of user facilities is growing worldwide thanks to their compactness and reduced costs. The EuPRAXIA@SPARC_LAB collaboration is preparing a technical design report for a multi-GeV plasma-based accelerator with outstanding electron beam quality to pilot an X-ray FEL, the most demanding in terms of beam brightness. The beam dynamics has been studied aiming to a reliable operation of the RF injector to generate a so-called comb-beam with 500 MeV energy suitable as driver of the Beam-driven Plasma Wakefield Accelerator. A case of interest is the generation of a trailing bunch with 1 GeV energy, less than 1 mm-mrad transverse emittance and up to 2 kA peak current at the undulator entrance. The comb-beam is generated through the velocity bunching technique, an RF compression tool that enables high brightness beams within relatively compact machine. Since it is based on a rotation of the beam phase space inside the external RF fields, it could be particularly sensitive to amplitude and phase jitters in the RF injector. The electron beam dynamics and the machine sensitivity to the possible jitters are presented in terms of effect on the beam quality so to provide the basis for the alignment procedure and jitter tolerances. Numerical studies have been consolidated with experimental results obtained at SPARC_LAB, a test facility currently oriented to plasma acceleration physics where the velocity bunching scheme is routinely applied.
Paper: TUPL130
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL130
About: Received: 11 May 2023 — Revised: 06 Jun 2023 — Accepted: 06 Jun 2023 — Issue date: 26 Sep 2023
TUPL135
Beam Dynamics Optimization of an Electron Linac Using the Multi-Objective Genetic Algorithm
2049
A beam dynamics optimization study of an electron injector linear accelerator including an RF photoinjector gun was performed using MOGA (Multi-Objective Genetic Algorithm). To meet the requirements of electron beam characteristics at the linac end, the optimization goal was to minimize transverse beam emittance and energy spread. The transverse and longitudinal beam sizes were constrained to find Pareto fronts effectively. Parameters to be optimized were the input phases of the RF gun cavity and accelerator column cavity as well as the strength and position of the focusing solenoids. In addition to finding physical optimization parameters, we also investigated hyper-parameters in optimization simulations such as population, offsprings, generations, etc. This paper presents the optimization results of the linac design.
Paper: TUPL135
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL135
About: Received: 01 May 2023 — Revised: 20 Jun 2023 — Accepted: 20 Jun 2023 — Issue date: 26 Sep 2023
TUPL141
Distributed coupling linac for efficient acceleration of high charge electron bunches
2064
Future colliders will require injector linacs to accelerate large electron bunches over a wide range of energies. For example the Electron Ion Collider requires a pre-injector linac from 4 MeV up to 400 MeV over 35 m [1]. Currently this linac is being designed with 3 m long traveling wave structures, which provide a gradient of 16 MV/m. We propose the use of a 1 m distributed coupling design as a potential alternative and future upgrade path to this design. Distributed coupling allows power to be fed into each cavity directly via a waveguide manifold, avoiding on-axis coupling [2]. A distributed coupling structure at S-band was designed to optimize for shunt impedance and large aperture size. This design provides greater efficiency, thereby lowering the number of klystrons required to power the full linac. In addition, particle tracking analysis shows that this linac maintains lower emittance as bunch charge increases to 14 nC and wakefields become more prevalent. We present the design of this distributed coupling structure, as well as cold test data and plans for higher power tests to verify on the structure’s real world performance.
Paper: TUPL141
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL141
About: Received: 02 May 2023 — Revised: 09 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
TUPL143
Jitter tolerance for the FEBE beamline on CLARA
2071
CLARA at STFC Daresbury Laboratory is a test facility for FEL research and novel accelerator technologies, providing high-quality electron bunches with charges up to 250 pC. Phase two of CLARA, which will bring the accelerator to its design energy (250 MeV) and repetition rate (100 Hz), is expected to begin commissioning in 2024. To maximise exploitation of the upgraded accelerator, a dedicated Full Energy Beam Exploitation (FEBE) beamline is currently being installed, featuring two large chambers where a high-power laser and advanced diagnostics will be available for user experiments that include investigation of novel plasma acceleration methods. Many experiments planned for CLARA-FEBE will require a high level of shot-to-shot beam stability, placing particular importance on the bunch time of arrival (tens of femtoseconds) and peak current (several kiloamperes). Accurate modelling of beam jitter will therefore be critical for the purposes of planning user experiments, and for future work to mitigate the dominant jitter sources in the machine. In this contribution, we investigate the jitter tolerance of CLARA-FEBE using start-to-end simulations of the accelerator complex.
Paper: TUPL143
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL143
About: Received: 03 May 2023 — Revised: 09 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
TUPL153
Beam dynamics optimization of a modular and versatile linear accelerator-based system exploiting C-Band technology for VHEE FLASH Applications
2097
In the framework of a collaboration between Sapienza University of Rome, the Italian Institute for Nuclear Research (INFN) and the Curie Institute, the proposal of a new facility dedicated to the Very High Electron Energy (VHEE) FLASH irradiation is in progress. The aim is to exploit the promising VHEE regime for the translation of electron FLASH radiotherapy into clinical practice in order to treat deep tumors. For the translation to clinical practice, the electron energy should be varied in the 60-160 MeV range. The needed electron peak current is the order of 200 mA, that is 200 nC per 1 $\mu$s pulse. The irradiation system also requires compactness for the installation inside a hospital or treatment facility. In order to satisfy both requirements, i.e. high energy and compact system, we propose a radio-frequency (RF) linear accelerator-based electron-beam source working in C-band at 5.712 GHz. In particular, we present the beam dynamics of the optimized high-gradient C-band linear accelerating system for the transport of high beam current beams for FLASH applications.
Paper: TUPL153
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL153
About: Received: 01 May 2023 — Revised: 24 May 2023 — Accepted: 22 Jun 2023 — Issue date: 26 Sep 2023
TUPL154
Planning, installation and testing of the RF system for the upgrade of the Star facility
2101
In 2021, the Italian Institute for Nuclear Physics (INFN) was awarded the project for installing, testing and commissioning the energy upgrade of the Southern European Thomson back-scattering source for Applied Research (STAR) which is currently installed at the University of Calabria (UniCal). The STAR high-energy Linac, STAR-HEL, consists in a layout comprising RF accelerating structures (linacs), with relative magnetic optics components, in order to boost the electron beam energy from 65 MeV up to 150 MeV. In this paper, we discuss the status of the planning, installation and testing of the RF system (accelerating structures, power, network and LLRF) based on C-band (i.e. 5712 MHz RF frequency) technology. For this purpose, two C-band linacs are installed and are independently powered by two RF power stations, located aside the present S-band RF power station, which will deliver 42 MW (nominal) peak power RF pulses of 1us width and up to 100 Hz repetition rate. Operation in C-band permits acceleration with higher gradients, resulting in a more compact linac footprint.
Paper: TUPL154
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL154
About: Received: 02 May 2023 — Revised: 18 May 2023 — Accepted: 22 Jun 2023 — Issue date: 26 Sep 2023
TUPL155
High power test results of diode E-Gun based 4-6 MeV Accelerator Beam Centerline (ABC)
2104
Varex Imaging High Energy Sources Group has developed, built, and tested a Diode Electron Gun (DEG) based 6 MeV Accelerator Beam Centerline ABC-6-S-X-D, which showed excellent performance results, and has been entered into a serial production. The ABC is very similar in performance to its Varian-produced counterpart and may be used as its drop-in replacement in the existing installed Varex linac system base, which exceeds 1000 units. While we intend to utilize a Triode Electron Gun (TEG) based ABC in all new products, this DEG based design can also be used in linac systems for security screening, non-destructive testing, and medical applications. This paper presents high power test results of the developed ABC-6-S-X-D.
Paper: TUPL155
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL155
About: Received: 26 Apr 2023 — Revised: 28 Jun 2023 — Accepted: 28 Jun 2023 — Issue date: 26 Sep 2023
TUPL156
High voltage e-gun for LINAC
2106
A typical commercially available thermionic triode e-gun operates in 10-15 kV range. Certain linac accelerating structures may benefit from higher voltage injection. Based on commercially available low voltage e-guns Varex Imaging High Energy Sources Group has developed an e-gun that could be operated in extended range of voltages of 10-40 kV, provides high adjustability of injecting beam parameters. The new e-gun can be utilized with both triode and diode options
Paper: TUPL156
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL156
About: Received: 26 Apr 2023 — Revised: 28 Jun 2023 — Accepted: 28 Jun 2023 — Issue date: 26 Sep 2023
TUPL162
Brixsino high-flux dual X-ray and THz radiation source based on energy recovery linacs
2123
We present the conceptual design of a compact light source named BriXSinO. BriXSinO was born as a demonstrator of the Marix project, but contains also a dual high flux radiation source Inverse Compton Source (ICS) of X-ray and a Free-Electron Laser Oscillator of THz spectral range radiation conceived for medica applications and general applied research. The accelerator is a push-pull CW-SC Energy Recovery Linac (ERL) based on the technology of superconducting cavities and allows to sustain MW-class beam power with al-most just one hundred kW active power dissipation/consumption. ICS line produces 33 keV monochromatic X-Rays via Compton scattering of the electron beam with a laser system in Fabry-Pérot cavity at a repetition rate of 100 MHz. The THz FEL oscillator is based on an undulator imbedded in optical cavity and generates THz wavelengths from 15 to 50 micron. The possibility of generating in the FEL cavity also synchronized X radiation is also shown.
Paper: TUPL162
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL162
About: Received: 03 May 2023 — Revised: 22 May 2023 — Accepted: 22 May 2023 — Issue date: 26 Sep 2023
TUPL169
Studies on a triple-turn energy-recovery mode at the S-DALINAC
2143
The electron accelerator S-DALINAC at TU Darmstadt was successfully operated in single and double-turn energy-recovery mode. The latter was realized using a shared beam-transport where two beams are superimposed in the first recirculation beamline. Due to its current design, the S-DALINAC can be upgraded with reasonable effort to be operated in triple-turn energy-recovery mode with shared beam-transport. Here, two beams are superimposed in both, the first and the second recirculation beamline. This mode is particularly challenging due to a reduced number of degrees of freedom compared to an individual beam-transport. Therefore, the triple-turn energy-recovery mode requires precise determination of the accelerator setup obtained from beam-dynamics simulations prior to beam-tuning. The results of the necessary beam-dynamics simulations for this mode are presented.
Paper: TUPL169
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL169
About: Received: 03 May 2023 — Revised: 23 May 2023 — Accepted: 23 May 2023 — Issue date: 26 Sep 2023
TUPL170
Modeling of standing wave RF cavities for tracking through multi-pass energy recovery linac
2147
Short bunches, high current and multiple linac pass are all characteristics of Energy Recovery Linacs (ERLs), which may result in collective effects. They in turn, may affect the beam, degrading its quality, or even yield to instabilities causing a beam loss. To study and mitigate these effects one needs a numerical simulation code, that can take into account both the collective effects, as well as, particular ERL features, such as a multi-turn design that does not reach a steady state or the multiple passages of the beam through Radio-Frequency (RF) cavities at different energies. CODAL [1], a code developed by SOLEIL in collaboration with IJCLab, enables such studies. It is a 6 dimensional (6D) tracking code applying 'kicks' based on the integration of the local Hamiltonian for each element of the lattice. It is also capable of simulating space charge, wakefields and coherent synchrotron radiation. However, to correctly take into account the ERL dynamics, an upgrade had to be made to include the effect of a standing wave RF cavity in 6D. In this paper, we will concentrate on the implementation and benchmarking (with DESY’s tracking code ASTRA [2]) of both the longitudinal and the transverse models (by J.B. Rosenzweig and L. Serafini [3]), which we use to carry out tracking of fully analytical 6D RF cavity.
Paper: TUPL170
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL170
About: Received: 03 May 2023 — Revised: 06 Jun 2023 — Accepted: 06 Jun 2023 — Issue date: 26 Sep 2023
TUPL171
Lattice design of 250 MeV version of Perle
2151
The PERLE (Powerful Energy Recovery LINAC for Experiment) collaboration is developing a high power energy recuperation linac facility with three acceleration (up to 500 MeV) and three deceleration passes through two cryo-modules at an injection current of 20 mA. Here we present the lattice design of the first stage of this machine with one cryo-module that would demonstrate the six-passes operation with a maximal energy of 250 MeV at a high current. This lattice has a simpler design with less elements therefore it requires lower initial expenses and shorter construction and commissioning times. All the magnets and the cryo-module are chosen to be compatible with both stages to minimise the costs of upgrade to a final one.
Paper: TUPL171
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPL171
About: Received: 03 May 2023 — Revised: 07 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
TUPM002
Commissioning status of the RAON superconducting accelerator
2192
The Rare isotope Accelerator Complex for ON-line experiments (RAON) has been proposed as a multi-purpose accelerator facility for providing beams of exotic rare isotopes of various energies. It can deliver ions from hydrogen (proton) to uranium. Protons and uranium ions are accelerated up to 600 MeV and 200 MeV/u respectively. It can provide various rare isotope beams which are produced by isotope separator on-line system. The RAON injector was successfully commissioned in 2022 to study the beam parameters from the main technical systems, such as the ECR ion source and RFQ, and to find the optimized LEBT and MEBT setpoints and matching conditions. In addition, the low-energy superconducting linac (SCL3) is under commissioning. In this paper, we present the current beam commissioning status of the RAON injector and superconducting accelerator.
Paper: TUPM002
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPM002
About: Received: 03 May 2023 — Revised: 11 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
TUPM007
High-gradient accelerating structures for proton radiography booster linac
2205
Increasing energy of proton beam at the Los Alamos Neutron Science Center (LANSCE) from 800 MeV to 3 GeV will improve radiography resolution ten-fold. This energy boost can be achieved with a compact cost-effective linac based on normal conducting high-gradient (HG) RF accelerating structures. Such an unusual booster is feasible for proton radiography (pRad), which operates with short beam pulses at very low duty. The pRad booster starts with a short L-band section to capture and compress the 800-MeV proton beam from the existing linac. The main HG linac is based on S- and C-band cavities. An L-band de-buncher at the booster end reduces the beam energy spread at 3 GeV three times below that at the exit of the existing 800-MeV linac. We continue developing proton HG standing-wave structures with distributed RF coupling for the booster. Results of measurements for a two-cell test cavity at the LANL C-band RF Test Stand and a comparison with conventional traveling-wave structures are presented.
Paper: TUPM007
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPM007
About: Received: 02 May 2023 — Revised: 05 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
TUPM008
Electromagnetic and beam dynamics modeling of the LANSCE coupled-cavity linac with CST studio
2209
The 800-MeV proton linac at the Los Alamos Neutron Science Center (LANSCE) includes a drift-tube linac, which brings the beam to 100 MeV, followed by a coupled-cavity linac (CCL) consisting of 44 modules. Each CCL module contains multiple tanks, and it is fed by a single 805-MHz klystron. CCL tanks are multi-cell blocks of identical re-entrant side-coupled cavities, which are followed by drifts with magnetic quadrupole doublets. Bridge couplers – special cavities displaced from the beam axis – electromagnetically couple CCL tanks over such drifts. We have developed 3D CST models of CCL tanks. The RF fields in the tanks are calculated with MicroWave Studio, and magnetic fields of quadrupole doublets are found with ElectroMagnetic Studio. Beam dynamics is modeled with Particle Studio for bunch trains with realistic beam distributions using the CST calculated fields to determine the output beam parameters. Beam dynamics results are compared with other multi-particle codes and provide data for training physics-based surrogate models.
Paper: TUPM008
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPM008
About: Received: 01 May 2023 — Revised: 05 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
TUPM015
Comparison of design and production RF settings at SNS normal temperature linac
2219
The beam optics in the SNS normal conducting linac is analyzed for the 1.4 MW beam-on-target operation settings. The first section is a room temperature copper linac which include Medium Energy Beam Transport (MEBT) section with four re-bunching radio-frequency (RF) cavities, Drift Tube Linac (DTL), and Coupled Cavity Linac (CCL). The Radio Frequency (RF) cavities in this section accelerate H- beam to 185.5 MeV. For production runs the parameters of RF cavities in this section are chosen by using combination of models and empirical tuning providing low beam loss and low rate of discharge events inside the cavities. For some cavities the set parameters are significantly different form the design values. The paper discusses accuracy of these settings and discrepancies between design and real-life high-power production settings in the warm linac section of SNS.
Paper: TUPM015
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPM015
About: Received: 01 May 2023 — Revised: 05 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
TUPM048
The development of aggregation diagrams for high-level planning at the ESS
2305
Accelerator facilities are among the most complex projects, integrating advanced engineering systems and components. At the ESS, the need to visualise the intricate integration activities has led to the development of Aggregation Diagrams (ADs). The diagrams follow the facility breakdown structure with sections and system diagrams showing their integration of the devices with enabling and interfacing systems such as the vacuum, cooling, power suppliers and control systems. Commissioning diagrams have also been developed and are used to visualise the main steps and events in the commissioning of the accelerator. The main advantage of using ADs is to help in the activities planning, provide easy access to high-level plans and develop a standard tool that could be used among the different work packages. In this paper, we present the workflow on the development of ADs giving some examples of their use in the activities planning at the ESS.
Paper: TUPM048
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPM048
About: Received: 03 May 2023 — Revised: 08 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
TUPM058
Measurement and analysis of the intensity-dependent effects on the CSNS medium energy beam transport line
2323
The China Spallation Neutron Source (CSNS) has been operated with 100kW beam power on target since 2020. The Linac consists of an H- ion source, a low-energy beam transport line (LEBT), a 3 MeV Radio Frequency Quadrupole (RFQ), a Medium Energy Beam Transport line (MEBT) and a Drift Tube Linear (DTL) accelerator to boost the beam energy to 80 MeV with a beam intensity of 10 mA. A power upgrade project (CSNS-II) has been approved in 2021 to increase the beam power to 500 kW, for which the Linac energy will reach 300 MeV and the beam intensity is expected to be 50 mA. Now we are gradually increasing the beam intensity of the CSNS Linac to fully explorer its capability and furtherly deepen our understanding of the properties of high intensity beam. In this study, we show the beam measurement results given by the wire scanners and the emittance monitor at various current intensities, and the numerical modeling and fitting methods to obtain the evolution of the beam envelope and emittance along the CSNS MEBT.
Paper: TUPM058
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPM058
About: Received: 29 Mar 2023 — Revised: 10 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
TUPM066
Reliability analysis of SNS SRF linac and perspective for future high-power proton SRF linacs
2349
Future proton superconducting RF (SRF) linacs used as accelerator driven systems (ADS) must achieve high reliability and availability to meet the challenging parameters for applications in medical treatment, nuclear waste reduction, and nuclear power generation. What SRF innovations and advanced concepts are needed? To answer this question, a case study of the past, current, and possible future downtime sources is carried out for the Spallation Neutron Source (SNS) SRF linac systems. SNS is an accelerator-driven neutron source facility routinely operated at a 1.4 MW beam power with a 99% availability in its SRF systems and is currently undergoing an upgrade to a new level capable of a 2.8 MW beam power. The preliminary outcome of this study is to be presented. We will discuss its implications to the needed development of the next generation SRF systems and related systems towards 10-20 MW proton SRF linacs required for future ADS facilities.
Paper: TUPM066
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPM066
About: Received: 26 Apr 2023 — Revised: 12 May 2023 — Accepted: 23 Jun 2023 — Issue date: 26 Sep 2023
TUPM092
The new proton beam delivery line of the TOP-IMPLART accelerator
2423
A new proton beam-delivery line for the TOP-IMPLART linac is under assembly and testing at the ENEA Frascati Research Center. TOP-IMPLART is an RF pulsed linear accelerator developed for medical applications, consisting of a 425 MHz, 7 MeV injector, followed by eight accelerating SCDTL modules operating at 3 GHz, driven by two 10 MW peak power klystrons. Proton beam can be accelerated at 63 MeV or 71 MeV (other energy values can be achieved by suitable degraders) in 3µs pulses with a typical repetition rate of 25 Hz. Following the experience gathered in multi-year irradiation campaigns based on the use of a passive spreading in air of the beam, the new line employs a magnetic scanning system and has been designed to accommodate the requirements of different targets, for multipurpose applications ranging from radiobiology experiments, test of innovative dosimeters, up to qualification of components in the field of aerospace. The paper describes the setup, the monitors of the parameters of interest (dose, fluence, flux) integrated in the line, the control system and the first characterization measurements of the main elements.
Paper: TUPM092
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPM092
About: Received: 01 May 2023 — Revised: 11 May 2023 — Accepted: 12 May 2023 — Issue date: 26 Sep 2023
TUPM112
Benchmarking HPSim with the LANSCE Linac
2480
HPSim, the GPU-powered multi-particle simulation code developed for LANSCE, can provide critical 6-D beam distributions in near real-time to LANSCE user facilities. We will present the benchmarking results for HPSim to the LANSCE linac and our effort to provide a real-time distribution to the Isotope Production Facility.
Paper: TUPM112
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-TUPM112
About: Received: 02 May 2023 — Revised: 23 Jun 2023 — Accepted: 23 Jun 2023 — Issue date: 26 Sep 2023
WEODA1
Challenging students into developing accelerator-based innovations to protect the environment
2575
The I.FAST CBI is an immersive challenge-based innovation program funded by the H2020 I.FAST project. The 10-day face-to-face challenge brings together students of different disciplines from all over Europe to work together on innovative projects using accelerator technology applied to environmental challenges. We report on the first edition of the I.FAST CBI, the proposed projects and feedback from the students.
Paper: WEODA1
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEODA1
About: Received: 07 May 2023 — Revised: 20 Jun 2023 — Accepted: 20 Jun 2023 — Issue date: 26 Sep 2023
WEYG1
The IFMIF-DONES facility: a fusion-oriented 5 MW superconducting CW linear accelerator
2599
IFMIF-DONES (International Fusion Materials Irradiation Facility, DEMO-Oriented Neutron Early Source) – a powerful neutron irradiation facility for irradiation of materials to be used in fusion reactors – is planned as part of the European roadmap to fusion electricity. Its main goal will be to characterize and qualify materials under a neutron field similar to the one faced in a fusion reactor, developing a material database for the future fusion nuclear reactors. The facility is based on an intense neutron source produced by a high current deuteron beam impinging on a liquid lithium curtain, aiming to generate by stripping reactions neutrons with an energy spectrum and flux similar to those expected to be seen by the first wall of a fusion reactor. The IFMIF-DONES facility has accomplished the preliminary design phase and currently in its detailed design phase. The next phase will be the preparation for the construction of the facility. This contribution presents the status of IFMIF-DONES design developed in the framework of the EUROfusion work programme, integrating the lesson learnt from the IFMIF/EVEDA Project (International Fusion Materials Irradiation Facility/ Engineering Validation and Engineering Design Activities - Broader Approach (BA) Agreement signed between EURATOM and Japanese Government), through a common program which includes the different commonalties and interfaces of the two projects. An overview of the present design status of the facility will be provided putting emphasis on the design status of the high current superconducting LINAC, responsible for delivering the 5 MW D+ beam at 40 MeV with very high inherent availability, focusing on the main challenges and the related R&D programme. The prospects for the construction and the commissioning of the facility in Granada (Spain) will be also reviewed.
Paper: WEYG1
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEYG1
About: Received: 04 May 2023 — Revised: 30 Jun 2023 — Accepted: 30 Jun 2023 — Issue date: 26 Sep 2023
WEOGB1
Status and plan of the European Spallation Source proton linac beam commissioning
2613
The European Spallation Source is a spallation neutron source driven by a superconducting proton linac and currently under construction in Lund, Sweden. The proton linac of a 5 MW design power, with a 62.5 mA peak current, 2.86 ms pulse length, and 14 Hz repetition rate, is undergoing staged beam commissioning towards the initial user operation planned in 2026 at a reduced power of 2 MW. In 2022, beam was accelerated up to 21 MeV with the first tank of a drift-tube linac (DTL), consisting of five tanks. Following the commissioning step this year (2023) up to the fourth DTL tank and 74 MeV, low power beam commissioning through superconducting structures is planned for the next year (2024), up to 570 MeV and against a beam dump. The last beam commissioning step prior to the initial user operation, when the beam is sent to the spallation target, is planned for 2026. This paper provides a summary of the past beam commissioning activities and presents the current strategy for the upcoming beam commissioning steps, including machine configuration at each step.
Paper: WEOGB1
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEOGB1
About: Received: 10 May 2023 — Revised: 10 May 2023 — Accepted: 21 Jun 2023 — Issue date: 26 Sep 2023
WEOGB3
Implementation status of MYRRHA phase 1 (MINERVA)
2617
The MYRRHA design for an accelerator driven system (ADS) is based on a 4mA, 600 MeV CW superconducting proton linac. The first stage towards its realization is called MINERVA and was approved in 2018 to be constructed by SCK CEN in Belgium. This consist of a 4mA 100MeV superconducting linac as well as two independent target stations, one for radio-isotope research and production of radio-isotopes for medical purposes, the other one for fusion materials research. This contribution presents the main design choices and current status of the overall project parts (civil engineering, particle accelerator and target facilities).
Paper: WEOGB3
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEOGB3
About: Received: 26 Apr 2023 — Revised: 06 Jun 2023 — Accepted: 06 Jun 2023 — Issue date: 26 Sep 2023
WEPA002
Suppression of microbunching instability based on optimized velocity bunching in linac-driven FELs
2646
The microbunching instability (MBI) driven by beam collective effects can cause significant electron beam quality degradation in advanced x-ray free electron lasers. Typically, multiple stage magnetic bunch compressors used to generate high peak current electron beam will dramatically amplify the microbunching instability. In this paper, by redesigning the solenoid elaborately and adopting a dual-mode buncher cavity with the third harmonic mode used to correct the RF curvature, it is potential for the electron beam to be further compressed in VB process. Therefore, a VB plus one bunch compressor could be a promising alternative scheme to achieve moderate peak current beam for high-repetition-rate X-ray FELs to suppress the additional MBI gain due to multi-stage magnetic bunch compressors.
Paper: WEPA002
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPA002
About: Received: 03 May 2023 — Revised: 06 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
WEPA030
Current Status of the Beam Dynamics Simulations for the HBS Drift Tube Linac
2721
As various experimental reactors in Europe are already or will be decommissioned over the next years, new neutron sources will be necessary to meet the demand for neutrons in research and development. The High Brilliance Neutron Source is an accelerator driven neutron source planned at the Forschungszentrum Jülich. The accelerator will accelerate a proton beam up to an end energy of 70 MeV, using normal conducting CH-type cavities. Because of the high beam current of 100 mA, the beam dynamics concept requires special care. In this paper, the current status of the beam dynamics for the drift tube linac is dicsussed.
Paper: WEPA030
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPA030
About: Received: 03 May 2023 — Revised: 10 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
WEPA034
Characterization of high dynamic range beam emittance
2724
Measurement of hadron beam emittances with very high dynamic range, one part-per-million and above, become available recently. This level of dynamic range is required for studying the origin and evolution of the halo in high intensity hadron linacs. There are no established or commonly known metrics to describe such distributions. Using data from the emittance measurements of 2.5Mev H- beam at the SNS Beam Test Facility we demonstrate that most common emittance metrics the RMS emittance and the Halo parameter H are totally insensitive to low level features of the distribution. We also suggest a new metric, which is unambiguously computable, invariant of linear simplectic transformations, and capturing features important for low loss beam transport.
Paper: WEPA034
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPA034
About: Received: 04 May 2023 — Revised: 06 Jun 2023 — Accepted: 06 Jun 2023 — Issue date: 26 Sep 2023
WEPA051
Microbunching gain evaluation of bunch stretcher designs
2774
The planned Electron Ion Collider (EIC) has an Energy Recovery Linac (ERL) which provides Strong Hadron Cooling (SHC) in order to control the beam quality of the hadrons. This requires that the electron beam delivered to the cooling section be minimally perturbed by the preceding bunch stretcher necessary in the 100 GeV configuration. This paper evaluates different stretcher designs for the SHC ERL, based on current design requirements.
Paper: WEPA051
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPA051
About: Received: 03 May 2023 — Revised: 22 May 2023 — Accepted: 22 May 2023 — Issue date: 26 Sep 2023
WEPA078
Symplectic neural surrogate models for beam dynamics
2825
The self-consistent nonlinear dynamics of a relativistic charged particle beam interacting with its complete self-fields is a fundamental problem underpinning many of the accelerator design issues in high brightness beam applications, as well as the development of advanced accelerators. A novel self-consistent code is developed based on a Lagrangian method for the calculation of the particles’ radiation near-fields using wavefront/wavelet meshes via the Green’s function of the Maxwell equations. These fields are then interpolated onto a moving mesh for dynamic update of the beam. This method allows radiation co-propagation and self-consistent interaction with the beam in 2D/3D simulations at greatly reduced numerical errors. Multiple levels of parallelisms are inherent in this method and implemented in our code CoSyR [1] to enable at-scale simulations of nonlinear beam dynamics on modern computing platforms using MPI, multi-threading, and GPUs. Our simulations reveal the slice emittance growth in a bend and the interplay between the longitudinal and transverse dynamics that occurs in a complex manner not captured in the 1D longitudinal static-state coherent synchrotron radiation model. Finally, we show that surrogate models with symplectic neural networks can be trained from simulations with significant time-savings for the modeling of nonlinear beam dynamics effects.
Paper: WEPA078
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPA078
About: Received: 10 May 2023 — Revised: 23 May 2023 — Accepted: 23 May 2023 — Issue date: 26 Sep 2023
WEPA085
Hellweg improvements for 3D traveling wave linac design with beam loading
2834
The industrial, medical and homeland security markets for low-to-moderate energy electron linacs are growing rapidly, often requiring beam currents that strongly load the accelerating fields. The two-beam accelerator (TBA) is one concept for the structure wakefield acceleration approach to an electron-positron collider. Transient beam loading effects are a significant challenge for the drive beam in a TBA structure, where energy droop in high-charge bunch trains must be understood and compensated. The Hellweg code accurately models steady state beam loading for traveling wave RF structures with a fast reduced model. The Hellweg equations of motion have recently been generalized to include arbitrary charge-to-mass ratio and to use momentum as the dynamical variable. These and other recent developments are discussed, including a new browser-based GUI. Proposed future developments include support of standing wave RF structures and transient beam loading effects.
Paper: WEPA085
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPA085
About: Received: 03 May 2023 — Revised: 11 May 2023 — Accepted: 23 Jun 2023 — Issue date: 26 Sep 2023
WEPA111
A low energy linac solution for 3D scanning applications
2912
Due to a recent interest in scanning thinner containers such as cars or aviation unit load devices (ULDs), lower energy linac solutions are required in order to obtain sufficient image contrast. In this work, we present the complete design of a C-band, bi-periodic, 2 MeV electron linac to fulfil this need. Multi-objective optimisation techniques are employed to optimise the RF cavities for maximum shunt impedance and to optimise the cell lengths/amplitudes of the bunching cavities to achieve a 90% capture efficiency. A full thermal analysis of the system, including the X-ray target, has been performed to explore the thermal management of the system, including a CFD analysis to estimate the effectiveness of typical thermal approximations made during the design process. Finally, a novel RF system for connecting and firing multiple linacs sequentially to generate quasi-3D images is described.
Paper: WEPA111
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPA111
About: Received: 01 May 2023 — Revised: 10 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
WEPA118
Upgrades of S-band Accelerating Structures and Pulse Compressors in the Electron and Positron Injector Linac of KEK
2932
New S-band disk-loaded TM01-2pi/3-travelling-wave structures and pulse compressors have been developed for upgrades of the injector linac for SuperKEKB and Photon-factory storage rings in KEK. The structures 2-m long have ingenious disk irises with oval fillets reducing discharge in high-power operation and modulations in radius suppressing beam break-up instabilities arising from HEM11 wakefields. The pulse compressors are of compact spherical-cavity-type resonating at the degenerate TE112 dipole modes with a high Q-value of 98,000 and yield a peak power gain of 6.2. The structures generate an acceleration gradient of 25.9 MV/m in power operation of 40 MW by using the pulse compressor and stably accelerate a two-bunch beam with a bunch charge of 4 nC.
Paper: WEPA118
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPA118
About: Received: 02 May 2023 — Revised: 10 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
WEPL035
Beam dynamics in the NEWGAIN project at GANIL-SPIRAL2
3192
The NEWGAIN (NEW GAnil INjector) project aims at supplying higher mass-to-charge ratio ions (from A/Q=3 to 7) with an energy of 590 keV/A to the present SC-Linac of SPIRAL2. It comprises a new SC source, a dogleg LEBT, an 88 MHz RFQ, and a MEBT, optimized for a current of up to 350 uA of uranium. Additionally, an extension of the present LEBT is considered to merge into the new one. This paper presents the last layout and beam dynamics results for these new lines, including the mass resolution, chopping, admittance slit and tuning scheme as the Design Study Phase ends.
Paper: WEPL035
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPL035
About: Received: 03 May 2023 — Revised: 11 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
WEPL055
Beam study on low dispersion CEBAF arcs
3240
The Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab employs recirculating linac SRF technology to generate a high polarization 12 GeV electron beam for nuclear physics users. New opportunities to study multipass energy recovery have also emerged with the proposal of a 5-pass energy recovery demonstration, ER@CEBAF. New beam optics with minimized beta functions have been developed and tested to avoid collective beam instabilities for multi-pass beams and meet the beam requirements of the nuclear physics community. To enable energy recovery for a common arc beam transport of five passes, achromatic and isochronous arc optics conditions were satisfied by re-designing the transverse optics of CEBAF. This paper focuses on beam studies conducted to study the newly-designed, low-dispersion, lowest energy arcs for CEBAF operations and ER@CEBAF.
Paper: WEPL055
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPL055
About: Received: 03 May 2023 — Revised: 22 Jun 2023 — Accepted: 22 Jun 2023 — Issue date: 26 Sep 2023
WEPL056
Re-design of CEBAF optics for ER@CEBAF
3244
ER@CEBAF is an effort to demonstrate multi-GeV multi-pass energy recovery with a low beam current in CEBAF. The race-track-shaped CEBAF geometry allows its linacs to accommodate multiple energy beams simultaneously. However, five energy recovery passes complicate the beamline optics design process. Individual recirculating arcs each transport one beam energy, and are shared between accelerating/decelerating beams. Present CEBAF optics needs to be redesigned to accommodate this additional multi-pass ER scheme. Isochronous arcs are retuned to match with the solutions obtained from optimized 10-pass beamline. In this paper, we discuss the optics redesign process with the existing beamline for ER@CEBAF.
Paper: WEPL056
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPL056
About: Received: 03 May 2023 — Revised: 06 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
WEPL072
Progress on the New Booster for SOLEIL II
3267
The SOLEIL II storage ring project will require an injected beam with small transverse and longitudinal sizes. To meet this requirement, a new multi-bend 14BA Higher-Order Achromat lattice has been de-signed to reduce the booster emittance from the pre-sent 140 nm.rad to 5 nm.rad @ 2.75 GeV. In this paper we report the progress in the booster beam dynamics studies, considering the linac energy increase from 110 to 150 MeV, and all errors coming from injection mag-nets, injected beam parameters, booster magnets and RF system, whereas the resistive wall study is reported elsewhere. The progress in designing the magnets, the vacuum system, the ramped power supplies, and the diagnostics is presented.
Paper: WEPL072
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPL072
About: Received: 26 Apr 2023 — Revised: 09 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
WEPL073
The MAX-IV linac with variable bunch compressors
3272
Recent studies have shown that accelerating $+19^{\circ}$ off-crest in all RF cavities in the MAX-IV linac reduces voltage-induced timing jitter from the klystrons. The current bunch compressors in the linac have fixed first-order longitudinal dispersion, and the RF phase is varied to control the amount of compression. Variable bunch compressor designs have been considered at MAX-IV in recent years, these would allow us to regain control over compression while the accelerating phase is fixed to reduce timing jitter. Particle tracking studies have been performed on the MAX-IV linac with the addition of arc-like variable bunch compressors.
Paper: WEPL073
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPL073
About: Received: 01 May 2023 — Revised: 05 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
WEPL183
Advances in a perturbation theory for the microbunching instability in free-electron laser injectors
3546
The microbunching instability is one of the most significant effects, which can lead to a severe degradation of the beam quality in the linac section of free-electron lasers. Direct analytical treatment of the microbunching instability is however challenging. In particular when multiple bunch compression stages are considered, an exact closed-form expression for the charge density of the electron bunch typically cannot be derived. As a remedy, perturbative methods might be considered. Here, the instability is investigated by analyzing the propagation of small perturbations to an otherwise stable phase-space density. One such approach is based on the expansion of the collective Perron-Frobenius operator of the collective system into a Frechet-Taylor series. Applying the expanded Perron-Frobenius operator to a slightly perturbed phase-space density allows to derive closed-form expressions for the propagated perturbation term, potentially to arbitrary order. In this contribution new advances in a perturbation theory based on the Frechet-Taylor expansion of collective Perron-Frobenius operators are presented.
Paper: WEPL183
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPL183
About: Received: 02 May 2023 — Revised: 11 May 2023 — Accepted: 20 Jun 2023 — Issue date: 26 Sep 2023
WEPL190
Advanced studies for the dynamics of high brightness electron beams with the code MILES
3574
High brightness electron beams enable a wide spectrum of applications ranging from short wavelength radiation sources to high gradient wakefield acceleration. The rich dynamics that are intrinsic in charged particles accelerated in complex systems require a careful description in the analysis and design of a given machine, particularly regarding its stability. Numerous computer codes are in use by the accelerator community for such purposes. In particular, MILES is a simple tracking code we have developed that allows fast evaluations of collective effects in RF linacs. In this paper we extend the simple models previously developed to describe specific, diverse applications that can benefit from the fast simulation tools developed in MILES. Examples of this kind include particle driven acceleration schemes in a plasma where driver and witness beams propagate in the ``comb" pulse-train configuration. Specifically, we investigate the self-induced fields excited within both the rf-linac stage and the capillary. Further, we discuss additional advanced topics such as wakefield effects in planar FEL undulators and the emission of coherent synchrotron radiation in a magnetic chicane.
Paper: WEPL190
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPL190
About: Received: 31 Mar 2023 — Revised: 08 Jun 2023 — Accepted: 08 Jun 2023 — Issue date: 26 Sep 2023
WEPM012
ESS spoke RF power station (400kwp@352mhz) soak testing: issues and mitigations
3593
The European Spallation Source (ESS) will accelerate a beam of protons with a beam pulse width 2.86ms long and pulse repetition frequency 14Hz. The acceleration will be provided by 155 cavities, out of which 97% of the cavities are superconducting. The first section of the ESS superconducting linac is the Spoke linac. The spoke linac increases the beam energy from 90MeV to 216MeV using the 26 superconducting Spoke cavities, resonant at 352MHz, situated in 13 cryomodules. The spoke cavities are powered by Spoke RF Power Stations (RFPS). The maximum power requirement for the spoke RFPS is 400kWp@352MHz. Outputs of two tetrode TH595A based amplifiers are combined to achieve 400kW output. The RFPS are delivered by Elettra as a part of Italian in-kind contribution towards the construction of ESS. The detailed design of RFPS is done by ESS and Elettra. At present, 27 RFPS are delivered to ESS. Out of these, 20 RFPSs are installed and commissioned at ESS gallery. Out of these, four RFPSs are under soak testing at 400kWp and four RFPSs are under soak testing at 300kWp. The present paper discusses test results, issues faced during soak testing and their possible mitigations.
Paper: WEPM012
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPM012
About: Received: 03 May 2023 — Revised: 12 Jun 2023 — Accepted: 12 Jun 2023 — Issue date: 26 Sep 2023
WEPM035
Installation and integrated testing of magnets for the ESS linac
3635
The European Spallation Source (ESS) linear accelerator is designed to accelerate a 62.5 mA, 2.86 ms, 14 Hz proton beam up to 2 GeV for delivery to a rotating tungsten (W) target. The beam transfer sections between linac cryomodules and approaching the target contain over 200 quadrupole, dipole and corrector magnets for beam envelope and trajectory control. In addition, a raster magnet system comprised of dual-plane dipoles is used to reduce beam density on the target. All magnets have been provided to ESS by in-kind collaborators, universities and research institutes across Europe. Following the delivery of these magnets and their respective power converters to ESS, this proceeding presents the status of the installation together with the methodology and first obtained results from integrated testing phase.
Paper: WEPM035
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPM035
About: Received: 01 May 2023 — Revised: 06 Jun 2023 — Accepted: 06 Jun 2023 — Issue date: 26 Sep 2023
THODB2
Overview and status of ESS RF systems
3932
The proton linac, for the European Spallation Source (ESS) currently in construction, will be powered by 155 high power RF systems. The RF systems will ultimately deliver in excess of 130 MW peak power, 5 MW of average power to a mixture of normal and superconducting accelerating structures at 352.21 and 704.42 MHz. ESS is a long pulse machine and will operate at 14 Hz with beam pulses of 2.86 ms. This paper will introduce the scope, system design and key technologies of the RF systems being deployed along the linac. We will present the installation and test status as well as initial experience from the operation of the first RF systems used for conditioning and first commissioning runs with beam. The RF systems have been designed to be as energy efficient as practical and we will present the results of a selection of the efficiency measures undertaken at ESS.
Paper: THODB2
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THODB2
About: Received: 08 May 2023 — Revised: 10 May 2023 — Accepted: 21 Jun 2023 — Issue date: 26 Sep 2023
THPA031
New digital low-level rf controls based on the red pitaya STEMlab for the tls linac system
4014
The Linac system at Taiwan Light Source (TLS) has been in operation for almost a quarter of a century and requires upgrades to improve its reliability. To achieve this, some components of the control system have been replaced with new digital low-level RF control units that use emerging technologies. A new unit is based on the open-source hardware platform which is named “Red Pitaya STEMlab” and offers a compact size and low power consumption. The unit features DAC blocks for downloading arbitrary waveforms with external trigger play and ADC blocks for waveform acquisition, enabling the development of real-time diagnostic toolkits. The new low-level RF control interface has been fully integrated into the existing EPICS software framework for system integration. The new digital low-level RF control system supports I/Q data with online amplitude and phase settings, and a waveform digitizer for inspecting low-level RF signals from the klystron modulator. Specific graphical applications have been designed and integrated into the existing operation interfaces. The system has been successfully achieved during routine operations. This paper describes the details of these efforts.
Paper: THPA031
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPA031
About: Received: 02 May 2023 — Revised: 09 May 2023 — Accepted: 20 Jun 2023 — Issue date: 26 Sep 2023
THPA048
Challenges for personnel safety systems during commissioning of ESS normal conducting linac
4063
The normal conducting part of the European Spallation Source (ESS) linear accelerator (Linac) entered the phase of staged beam commissioning in 2021. To allow carrying out commissioning activities and operating the normal conducting Linac (NCL), safe conditions for personnel must be assured, for which the Personnel Safety Systems (PSS) at ESS play a substantial role. The Personnel Safety System 1 (PSS1) is the PSS for NCL, and its purpose is to restrict access to NCL area and to ensure that personnel are protected from being harmed by exposure to ionizing radiation in the NCL, generated by the proton beam and high power radio frequency (RF) systems. It is being realized in three phases, which follows commissioning plan of the NCL: beam up to and including radio-frequency quadrupole (RFQ), beam up to and including drift tube Linac (DTL) 1, and beam up to and including drift tube Linac (DTL) 4. PSS1 is a first PSS where Personnel Access Station (PAS) and Material Access Station (MAS) have been used to access the area, and interfaces with the RF systems realized to allow RF systems testing. It faced many challenges during the first two phases, and preparation for the third one, which will be described in this paper.
Paper: THPA048
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPA048
About: Received: 01 May 2023 — Revised: 08 May 2023 — Accepted: 23 Jun 2023 — Issue date: 26 Sep 2023
THPA060
Development of a Tool for Cavity Failure Compensation in Superconducting Linacs: Progress and Comparative Study
4097
Reliability in high power hadron accelerators is a major issue, particularly for Accelerator Driven Systems (ADS). For example, the Japan Atomic Energy Agency (JAEA) ADS maximum frequency of beam trips longer than 5 min was set to 42 per year. A significant number of breakdowns are caused by the failure of accelerating cavities or by their associated systems. Hence, we studied how these can be effectively reduced. To this end, we developed the numerical tool LightWin that aims to determine the compensation settings for any superconducting (SC) linac automatically and systematically [1]. This tool has been successfully used for the MYRRHA SC linac. In this work, we applied LightWin to compensate for several failure scenarios involving the last section of the JAEA linac and compared the associated retuned settings and beam performance to those found in a previous study [2] with TraceWin.
Paper: THPA060
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPA060
About: Received: 01 May 2023 — Revised: 05 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
THPA069
Phase reference line synchronization for LCLS-I and LCLS-II at SLAC
4125
With LCLS-II commissioning started and transfer-to-operations being scheduled, users will have more choices to use different scales of X-Ray FEL. LCLS-I instrument hutches and the beam diagnostic systems at SLAC have the requirements to use the same facilities to detect the X-Rays or electron beams from both LCLS-I and LCLS-II accelerators. Synchronization of the phase reference systems between the two machines is the prerequisite to achieve this goal. The LINAC Locking System at SLAC replaces the LCLS-I stand-alone 476 MHz master oscillator with one derived from the LCLS-II 1300 MHz phase reference signal. The phase initiation is realized with the timing alignment of the LCLS-I LINAC event generator (EVG) to the LCLS-II timing pattern generator (TPG) using a common subharmonic frequency. The new low noise 476 MHz phase reference is to be distributed to LCLS-I LINAC master oscillator and the instrument hutches via RF-over-Fiber system over a 1km distance in an uncontrolled environment. This paper will discuss the system design architecture and the test results gathered during the system's commissioning.
Paper: THPA069
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPA069
About: Received: 31 Mar 2023 — Revised: 05 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
THPA091
Expansion of the µTCA based direct sampling LLRF at MedAustron for hadron synchrotron applications
4168
The MedAustron Ion Therapy Centre is a synchrotron-based particle therapy facility, which delivers proton and carbon beams for clinical treatments. Currently, the facility treats 40 patients per day and is improving its systems and workflows to further increase this number. Although MedAustron is a young and modern center, the life-cycle of certain crucial control electronics is near end-of-life and needs to be addressed. This paper covers the expansion of the direct sampling µTCA based LLRF system presented in posters at Linac2022* and IBIC2022**. These extensions are particle beam-based regulation loops, which allow regulation of the heavy ion beams in the synchrotron. At the moment a phase regulation loop, to align cavity phases to beam phases, and a radial position regulation loop, to keep the beam orbit centered in the beam pipe are realized. Both of these additions rely on the already implemented real time configurable NCOs, the cavity regulation and the position measurement already presented in the posters mentioned above. The regulation can act on the base frequency of the NCO or the requested cavity phase to attain the requested setpoint.
Paper: THPA091
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPA091
About: Received: 03 May 2023 — Revised: 22 May 2023 — Accepted: 22 May 2023 — Issue date: 26 Sep 2023
THPA100
An advanced digital feedback control system design for the muon linear accelerator
4194
A unique muon linear accelerator (linac) for the muon g-2/EDM experiment at J-PARC is under development. Digital feedback (DFB) design employed in a low-level radio frequency (LLRF) control system is crucial to fulfilling the required RF amplitude and phase specifications in the RF cavities for a stable and continuous acceleration of the whole bunched particles. To this end, a micro telecommunications computing architecture.4 (MicroTCA.4)-based compact and in-house DFB design, using Vadatech commercial off-the-shelf (COTS) RF system-on-chip (RFSoC) advanced mezzanine card (AMC), is aimed for the muon linac. This feedback control system will employ a direct sampling method that reduces the project cost by requiring less hardware employment for ultra-high frequency (UHF) and L-band accelerating structures. The present status and first results of the project will be reported in this paper.
Paper: THPA100
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPA100
About: Received: 02 May 2023 — Revised: 05 Jun 2023 — Accepted: 20 Jun 2023 — Issue date: 26 Sep 2023
THPA101
Design study of 972-MHz RF and clock generator board at J-PARC linac
4198
In the J-PARC linac, the low-level RF (LLRF) with the digital feedback (DFB) and the digital feedforwaed (DFF) of the cPCI system had been adopted to satisfy the requirement of amplitude and phase stabilities. It has been operated without a serious problem so far. However, more than 15 years have passed since the construction of the J-PARC linac and the life of the apparatuses used since the time of construction is approaching. Some apparatuses are now discontinued and cannot be purchased, and others have problems such as software development environments that only use on older OSs. Therefore, we are starting to develop the next generation LLRF system. Currently, the 324-MHz LLRF stations, approximately half of all systems, are replaced by new DFB and DFF system based on MTCA.4. As a next step, we will develop new 972-MHz DFB and DFF system. The analog boards cannot be shared with the 324-MHz DFB and DFF system due to the different frequencies. The digital board will be re-examined to reduce the latency. In this paper, we would like to introduce the plan to replace the DFB and DFF systems at J-PARC Linac and show the design study of the RF and clock generator board.
Paper: THPA101
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPA101
About: Received: 11 May 2023 — Revised: 22 May 2023 — Accepted: 22 May 2023 — Issue date: 26 Sep 2023
THPA105
The Frascati DAFNE LINAC low level radio frequency status
4209
The Frascati linear accelerator was built in 1996 to be the electron and positron source and the front end of the DAFNE injector, is now also being used to support the DAFNE accelerator complex and the Beam Test Facility (BTF). The Frascati linear accelerator system consists of four S-band high-power klystron and modulator systems, fifteen accelerating structures, and four SLAC-type energy doubler cavity sleds all running at 2,856-MHz frequency. The Low Level RF distribution and status was upgraded starting from 2017. The original design of the TITAN BETA Low Level Radio Frequency system for the FRASCATI linac was briefly described and the upgrades applied in last years are discussed.
Paper: THPA105
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPA105
About: Received: 03 May 2023 — Revised: 12 Jun 2023 — Accepted: 12 Jun 2023 — Issue date: 26 Sep 2023
THPA125
Development progress of high-level applications for the HEPS
4259
The High Energy Photon Source (HEPS) is a 6 GeV, 1.3 km, 4th generation storage ring light source being built in Beijing, China. The HEPS storage ring is designed with an ultralow emittance of a few tens of pm rad. The development of high-level applications (HLAs) for HEPS started in early 2021. A new framework named PYthon-based Accelerator Physics Application Set (Pyapas) was developed for building HLAs. Based on Pyapas, the application development for Linac was completed in June 2022. And then the joint test with hardware system was performed, all the applications worked well in the Linac control room. Beam commissioning for the Linac began in March 9 of this year, and all the HLAs for the Linac are functioning well. The application development for the three transfer lines and the booster are essentially complete, with all the applications passing testing with virtual accelerator. Development of the HLAs for the storage ring began in November 2022. This paper will present a detailed progress on the development progress of HLAs for HEPS.
Paper: THPA125
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPA125
About: Received: 28 Apr 2023 — Revised: 09 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
THPL002
Development and commissioning of a new materials irradiation station at ATLAS
4416
A new dedicated materials irradiation beamline and target station was developed and recently commissioned at the ATLAS facility at Argonne National Laboratory. The new ATLAS Materials Irradiation Station (AMIS) is located just downstream of the first linac section (PII) and designed to receive heavy-ion beams with energies of 0.5 - 1.5 MeV/u. The main activity at AMIS is the irradiation of samples for radiation damage studies of nuclear materials. The facility will provide a unique accessible platform for accelerated testing of nuclear fuels and materials that support the testing and deployment of new materials for advanced reactors in a short period of time, which otherwise can take years of testing in conventional reactors. Although the focus of the AMIS line is to irradiate and investigate materials for nuclear energy applications, other research and applications are welcome. In particular, more beam time will be available following the completion of the ongoing ATLAS multi-user upgrade which will allow simultaneous beam sharing between different experimental stations. The development and commissioning results of the AMIS beamline will be presented and discussed.
Paper: THPL002
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPL002
About: Received: 04 May 2023 — Revised: 08 Jun 2023 — Accepted: 08 Jun 2023 — Issue date: 26 Sep 2023
THPL022
Virtual diagnostics for longitudinal phase space imaging
4471
For any linear accelerator, a thorough understanding of the Longitudinal Phase Space (LPS) of the beam is a great advantage. At the synchrotron light source MAX IV the two storage rings are injected with electrons using a 3 GeV linear accelerator, which also serves to provide beam for a short pulse facility (SPF). A newly commissioned Transverse Deflecting Cavity (TDC) is used to reconstruct the full LPS in a separate branch in the SPF after the second bunch compressor. This diagnostic performs a destructive measurement to extract the LPS and can not be used simultaneously with the beamline in the other branch in the SPF. In this paper we present a new virtual diagnostics which utilizes machine learning methods to extract the LPS information from other, non-destructive signals in the MAX IV linac. This involves simulations of the linac including the TDC response, as well as the collection of real data from the new TDC, for use in training artificial neural networks to predict the full LPS.
Paper: THPL022
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPL022
About: Received: 03 May 2023 — Revised: 05 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
THPL087
Emittance tuning bumps for the main linac of CLIC 380 GeV
4649
The high luminosity specifications for future linear colliders, such as the Compact Linear Collider (CLIC) require extremely small vertical beam emittance at the interaction point. This relies on minimizing the emittance growth in the collider sub-systems. One major source of emittance growth is the Main Linac, mainly caused by misaligned quadrupoles and accelerating structures. The current budget for the normalized emittance growth is 5 nm due to the static misalignments and another 5 nm due to the dynamic imperfections. The budget for the static imperfections is achieved through the use of beam-based alignment, such as one-to-one correction, dispersion-free steering, and the realignment of accelerating structures. This paper explores the use of additional emittance tuning bumps to further decrease the emittance growth, thereby increasing the luminosity.
Paper: THPL087
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPL087
About: Received: 03 May 2023 — Revised: 16 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
THPL091
Commissioning of ESS normal-conducting linac instrumentation and implications for future hadron linacs
4665
To support commissioning and early operation of the ESS normal-conducting linac, a variety of beam instrumentation systems have been deployed. These include beam chopping systems, Faraday cups, beam current monitors, and beam position and phase monitors as well as specialised systems such at wire scanners, emittance measurement units and neutron beam loss monitors. Commissioning has proceeded in three campaigns: proton beam through the Radio-Frequency Quadrupole to 3.6 MeV in 2021, through the first Drift Tube Linac (DTL) tank to 21 MeV in 2022 and through the first four DTL tanks to 74 MeV in 2023. In preparation for each campaign, the diagnostics team verified the measurement and protection functions of this instrumentation suite without beam. These functions were then verified with a low duty factor beam before finally declaring the systems operational. Throughout these verification activities and the succeeding commissioning stages, a rich data set was archived and analyzed. This paper describes the early experience with the ESS NCL instrumentation and, with a focus on lessons for future facilities, summarizes the data analysis techniques and results.
Paper: THPL091
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPL091
About: Received: 03 May 2023 — Revised: 09 May 2023 — Accepted: 23 Jun 2023 — Issue date: 26 Sep 2023
THPL094
Beam loss monitoring with fixed and translating scintillation detectors along the Fermilab drift-tube linac
4673
The Fermilab Linac is a roughly 145 meter linear accelerator that accelerates H- beam from 750 keV to 400 MeV and provides beam for the Booster and the rest of the accelerator chain. The first section of the Linac is a Drift-Tube Linac (DTL), which in its current state, suffers from a lack of instrumentation along its length. As a result, operational staff do not have access to the diagnostic information needed to tune the critical components of this accelerator, such as the quadrupole magnets within the drift tubes. This work presents an effort to utilize both fixed and translating scintillation detectors to investigate beam loss along the first two tanks of the Drift-Tube Linac.
Paper: THPL094
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPL094
About: Received: 03 May 2023 — Revised: 22 May 2023 — Accepted: 22 May 2023 — Issue date: 26 Sep 2023
THPL095
Measurement of beam energy in the Fermilab's Linac taken at the transfer line
4676
Linac is the first machine in the accelerator chain at Fermilab where H$^{-}$ ions are accelerated from 35 keV to 401.5\,MeV and then injected into a synchronton known as Booster where they are stripped of their electrons to become protons. One of the tools used during tuning of the Linac extraction energy is two beam pickups known as Griffin Detectors. Our goal is to control the output energy using machine learning techniques to increase the reliability and quality of the beam delivered from Linac. The first step is to understand the data from the diagnostics to develop reliable and accurate energy measurement, and control methods before implementing machine learning techniques. Two methods of energy measurement were studied, and their results are compared. The first method was the time of flight measurement using Beam Position Monitors that provide beam phase measurement. The second method used the relation between beam transverse positions and dispersion values to calculate momentum variation. The results of these two measurement methods are found to be consistent.
Paper: THPL095
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPL095
About: Received: 12 May 2023 — Revised: 06 Jun 2023 — Accepted: 06 Jun 2023 — Issue date: 26 Sep 2023
THPL117
Beam profile measurement using the highly-oriented pyrolytic graphite
4743
The mitigation of heat loading is one of the important issues for beam instrumentation to measure the high-power proton beam. Recently, the highly-oriented pyrolytic graphite (HOPG) material was used for the target probe of the bunch-shape monitor at the front-end in the Japan Proton Accelerator Research Complex (J-PARC). Since the thermal conductivity of the HOPG is high, it is suitable to measure the beam profile under the condition of high heat loading. As an application of the HOPG, for example, the thin HOPG may be used as a substitutive material of the target wire for the transverse profile monitor such as the wire scanner monitor. The possibility of the HOPG target for the beam profile monitor is discussed from some results of the test experiment using the 3-MeV negative hydrogen ion beam at the test stand.
Paper: THPL117
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPL117
About: Received: 28 Mar 2023 — Revised: 11 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
THPL132
Improving the phase stability of the 201.25 MHz BPPM reference for the LANSCE 805 MHz LINAC
4779
The Los Alamos Neutron Science Center (LANSCE) employs the use of BPPMs (Beam Position and Phase Monitors) to track the position and phase of beam throughout the site. In the past, BPPMs in the 805MHz CCL (Coupled Cavity Linac) section of the site used a 201.25MHz reference over facility network fiber, using RF media converters. This fiber reference distribution gave rise to give a large diurnal phase & temperature dependency causing a large error in beam phase measurement. A system was devised to use the site’s temperature controlled 805MHz reference divided by 4 as a 201.25MHz reference, with the n*90˚ phase uncertainty eliminated though measurement of phase between 805MHz divided by 4 and fiber 201.25MHz alongside a switched hybrid coupler network. Deployment of 7 phase reference units in 2022 allowed for greatly reduced error in beam phase measurement.
Paper: THPL132
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPL132
About: Received: 02 May 2023 — Revised: 09 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
THPL136
Longitudinal Electron Beam Characterisation at the MAX IV Linac
4787
The MAX IV 3 GeV linac delivers electron beams to two synchrotron rings and to a dedicated undulator system for X-ray beam delivery in the Short Pulse Facility (SPF). In addition, there are plans to use the linac as an injector for a future Soft X-ray Laser (SXL). For both SPF and SXL operations, longitudinal beam characterisation with a high temporal resolution is essential. For this purpose, a transverse deflecting cavity (TDC) system has been developed and installed in a dedicated electron accelerator line located downstream of the 3 GeV linac. This accelerator line consists of two consecutive 3 m long transverse S-band RF structures, followed by a variable vertical deflector dipole magnet used as an energy spectrometer. This conference contribution presents the beam dynamics calculations for the beam transport along the TDC line, and in particular the optics configurations for slice emittance measurements. The operation of an analysis algorithm for use in the control room is presented. The aim is to provide 1 fs temporal measurement resolution to access the bunch duration of highly compressed bunches and slice parameters for sub-10-fs bunches.
Paper: THPL136
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPL136
About: Received: 03 May 2023 — Revised: 05 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
THPL172
Bead-pull analysis of HOM in X-band linearizer linac on CLARA, with update on HOM measurement system
4859
The X-band lineariser linac planned to be installed on CLARA will be aligned using beam induced higher order modes (HOMs). Higher order modes in the cavity were studied using a bead-pull measurement technique. A software application was developed in LabVIEW to control the 3D motorised bead position scanning setup and VNA for S-parameter measurements. Propagation of HOM frequencies in the linac were verified, identifying the most suitable HOMs to use. Progress in development of HOM signal processing hardware system with dynamic control is also discussed in the paper.
Paper: THPL172
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPL172
About: Received: 02 May 2023 — Revised: 24 May 2023 — Accepted: 24 May 2023 — Issue date: 26 Sep 2023
THPL174
Qualitative measurements of bunch length at CLARA using coherent transition radiation
4863
Bunch length is an important metric for user experiments at the Compact Linear Accelerator for Research and Applications (CLARA). A prototype Bunch Compression Monitor (BCM) based on Coherent Transition Ration (CTR) was recently installed and commissioned to support recent user experiments. The intensity of CTR is measured using a pyroelectric detector. A noise cancellation scheme based on a second detector offset from the focus of the CTR was used to reduce the noise caused by the broadband nature of pyroelectric detectors. Qualitative measurements of the bunch length as a function of RF phase are presented, along with an overview of the system design. Plans for an improved system are also presented.
Paper: THPL174
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPL174
About: Received: 03 May 2023 — Revised: 24 May 2023 — Accepted: 24 May 2023 — Issue date: 26 Sep 2023
THPM020
Pure copper and stainless steel additive manufacturing of an IH-type linac structure
4931
Additive manufacturing ("AM") has become a powerful tool for rapid prototyping and manufacturing of complex geometries. A 433 MHz IH-DTL cavity has been constructed to act as a proof of concept for direct additive manufacturing of linac components. In this case, the internal drift tube structure has been produced from 1.4404 stainless steel, as well as pure copper using AM. The Prototype cavity, as well as stainless steel AM parts have been copper plated. We present results from low level rf measurements of the cavity with and without copper plating, as well as the status of preparations for high power rf tests with a 30 kW pulsed power amplifier.
Paper: THPM020
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPM020
About: Received: 01 May 2023 — Revised: 12 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
THPM035
First high quality DTL cavity additively manufactured from pure copper
4967
Recently presented RF cavity prototypes printed entirely from pure copper illustrate the potential of additive manufacturing (AM), and particularly laser powder bed fusion (L-PBF), for accelerator technology. Thereby, the design freedom of L-PBF is only limited by overhanging geometries, which have to be printed with supporting structures to ensure sufficient accuracy. However, subsequent removal of these support structures is a major challenge for cm-sized GHz cavities. Therefore, our approach is to design self-supporting geometries. In this contribution we present a DTL cavity geometry as used in e.g. proton therapy linac systems that can be fabricated by L-PBF without support structures. A 5-cell prototype was manufactured from high-purity copper using L-PBF. It is shown that the developed geometry allows a print accuracy sufficient to reach the defined resonance frequency. A chemical, as well as dynamic electrochemical finishing process, was applied to optimize the prototypes surface quality. Thus, the CST simulated figures of merit (e.g., $Q_0$, ${Z_{eff}}$) were obtained for the first time with a printed cavity.
Paper: THPM035
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPM035
About: Received: 19 May 2023 — Revised: 06 Jun 2023 — Accepted: 06 Jun 2023 — Issue date: 26 Sep 2023
THPM057
Preparations for beam commissioning of the carbon RFQ at CERN
5020
Linear accelerators for medical applications present the possibility to reduce costs compared to cyclotrons or synchrotrons while offering higher beam stability and flexibility. In the framework of NIMMS, the Next Ion Medical Machine Study, the design of a linear accelerator for carbon ion therapy has been completed at CERN. The pre-injector is composed of a fully stripped ${}^{12}\mathrm{C}^{6+}$ carbon ion source and a 750$\,$MHz Radio Frequency Quadrupole (RFQ) accelerating the beam to 5$\,$MeV/u. The Carbon RFQ is based on a compact, successfully commissioned 750$\,$MHz RFQ presently operating for the commercial proton therapy Linac facility LIGHT. The RFQ is divided in two independent RF cavities of 2$\,$m length. The first RFQ cavity, accelerating the ions to 2.5$\,$MeV/u, is currently being built by CIEMAT and its delivery to CERN is planned for 2023. It will be commissioned initially with a proton and then a helium beam. Beam characterization is crucial to validate the transmission to the next sections of the Linac. In this paper, we describe the diagnostic test bench and highlight the necessary measurements for the acceptance of the second RFQ cavity.
Paper: THPM057
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPM057
About: Received: 02 May 2023 — Revised: 06 Jun 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
THPM059
Development of reliable VHEE/FLASH passive dosimetry methods and procedures at CLEAR
5028
The electron beam at CERN Linear Accelerator for Research (CLEAR) has been intensively used to study the potential use of Very High Energy Electrons (VHEE) for radiotherapy, including the so-called FLASH regime. An important part of these studies revolves around the development of reliable dosimetry methods, given that generally accepted standards are partly lacking for electron beams in the 100 MeV range and even more so in the ultra-high dose rates (UHDR) conditions needed for FLASH. Passive dosimetry methods, such as radiochromic films and alanine pellets are presumed to be energy- and dose-rate independent and constitute an indispensable tool for VHEE studies. Furthermore, the development and testing of new modalities for active UHDR dosimetry relies heavily on them for validation and cross-calibration. In this context, efforts have been made to establish reliable and systematic approaches for passive dosimetry at CLEAR. This paper describes studies related to the processing of radiochromic films, the energy dependence of the dose measurements and comparisons with alanine pellets and other media.
Paper: THPM059
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPM059
About: Received: 03 May 2023 — Revised: 08 Jun 2023 — Accepted: 08 Jun 2023 — Issue date: 26 Sep 2023
THPM070
Design and test of C-band linac prototypes for electron flash radiotherapy
5056
The Flash Therapy is a revolution in the cancer cure, since it spares healthy tissue from the damage of the ionization radiations without decreasing its effectiveness in the tumor control. To allow the implementation of the FLASH therapy concept into actual clinical use and treat deep tumors, Very High Electron Energy (VHEE) should be achieved in range of 50-150 MeV. In the framework of VHEE project carried out at Sapienza University, in collaboration with INFN, we investigate the main issues in the design of a compact C band (5.712 GHz) electron linac for FLASH Radiotherapy. In this paper we describe the design strategy, the electromagnetic properties and the first prototype of the RF structure to be tested at Sapienza University.
Paper: THPM070
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPM070
About: Received: 10 Mar 2023 — Revised: 11 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
THPM087
SAFEST: a compact C-band linear accelerator for VHEE-FLASH radiotherapy
5079
FLASH Radiotherapy is a revolutionary new technique in the cancer cure. Several pre-clinical studies have demonstrated that treatment with electron radiation delivered with mean dose rates above 100Gy/s, an ultra-high instantaneous dose rate > 106Gy/s, and total irradiation time < 100ms, significantly decreases the toxicity in the healthy tissue while keeping the same efficacy in cancer treatment. Although recent studies shed some light on the biological mechanisms and on the effects of FLASH electron beams on tissues and organs of small animals, more research investigation is necessary before the FLASH technique can be translated into clinical applications. Researchers also aim to explore the radio-therapeutic effects of high-dose beams delivered at Very High Electron Energy (VHEE), in the range 50-250 MeV, suitable for treating deep-seated tumors. We describe the project SAFEST, carried out at La Sapienza University in collaboration with INFN for the realization of a compact C-band electron linac VHEE at the energy of 60-150 MeV, able to deliver the high current up to 200mA and the very high dose rates required by the FLASH regime, and suitable for a hospital environment.
Paper: THPM087
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPM087
About: Received: 05 May 2023 — Revised: 06 Jun 2023 — Accepted: 06 Jun 2023 — Issue date: 26 Sep 2023
THPM090
Innovations in the Next Generation Medical Accelerators for Therapy with Ion Beams
5083
Modern hadron-therapy accelerators have to provide high intensity beams for innovative dose-delivery modalities such as FLASH, pencil beams for 3D scanning, as well as multiple ions with radio-biological complementarity. They need to be compact, cheap and have a reduced energy footprint. At the same time, they need to be reliable, safe and simple to operate. Cyclotrons and compact synchrotrons are nowadays the standard for proton therapy. For heavier ions such as carbon, synchrotrons remain the most viable option, while alternative solutions based on linacs, FFAs or cyclotrons are being proposed. In this context, the European project HITRIplus studies the feasibility of an innovative super-conducting magnets synchrotron for carbon ions, with state-of-the-art multi-turn injection from a specially designed linac and advanced extraction modalities. A compact synchrotron optimized for helium ions, making use of proven normal-conducting technology, is also being designed.
Paper: THPM090
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPM090
About: Received: 09 May 2023 — Revised: 10 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
THPM098
Design, fabrication and verification of a 3MeV S-band medical linear accelerator
5111
ZAP-X is an innovative radiosurgery platform that is self-shielded, using gyroscopic motion to allow precision neurosurgical treatment. It requires a compact linac with lower than typical energy for medical applications. A 3 MeV S-band linac is designed and fabricated for this purpose. Thorough, clinical style testing was performed to verify the performance. The characteristics of photon beam, which is generated by the linac, are compared with the design goal, as well as Monte Carlo simulations.
Paper: THPM098
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPM098
About: Received: 21 Apr 2023 — Revised: 05 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
THPM105
Quantitative availability modelling for the MYRRHA accelerator driven system
5114
The availability of modern accelerators has become a key performance indicator. This is especially the case for accelerator-driven-systems (ADS), such as MYRRHA, which need to deliver beam with very few interruptions longer than a few seconds over a period of several months. Quantification of such beam interruptions at other accelerators such as LINAC4 at CERN and SNS at ORNL show that their fault count would need to be reduced by more than two orders of magnitude to comply with ADS requirements. Redundancy of systems is one viable strategy to achieve this. For MYRRHA, the use of redundant low-energy injectors, modular-redundant RF power amplifiers and serial-redundant RF cavities is presently proposed. The resulting gain in the accelerator availability using these redundant systems has been quantified by simulating the operation of the MYRRHA accelerator with AvailSim4, an availability-modelling tool developed at CERN. The study results highlight the importance to focus on optimizing system design and repair strategies to maximize the effectiveness of such redundancy schemes as well as the value of powerful availability simulation tools.
Paper: THPM105
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPM105
About: Received: 03 May 2023 — Revised: 07 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
THPM109
An objective approach to determining the steel penetration capabilities of X-ray cargo inspection systems
5124
The ANSI* steel penetration test is an important measure of the image performance capability of a cargo inspection system. Currently, the method for determining the arrow's visibility is completely subjective, as what one may deem 'visible', another may claim as not. An objective method is to calculate the contrast-to-noise ratio (CNR) between the steel plate and the arrow. A series of penetration scans were taken with the thickness of the steel plate ranging from 290-335 mm, and it was found that CNR decreases with increasing steel thickness. There is a point at which the CNR begins to level off - namely the 'limit of determination'. This is where the arrow can be objectively deemed as being no longer visible and, in this experiment, it was found to be at a CNR of around 0.23-0.25. Under-sampling the image data was also tested, and it was found that it did not have a detrimental effect on the CNR, and therefore the image performance. Once tested on more data sets, a definite value of the 'limit of determination' can be found. In future, this method has the capability of replacing the current method as an objective approach to determining the visibility of the arrow, and therefore measuring image performance using the steel penetration test.
Paper: THPM109
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPM109
About: Received: 24 Apr 2023 — Revised: 06 Jun 2023 — Accepted: 06 Jun 2023 — Issue date: 26 Sep 2023
THPM123
EUV-FEL light source for future lithography
5149
In EUV lithography, high volume manufacturing already started using a laser-produced plasma (LPP) source of 250-W power at 13.5 nm. However, development of a high-power EUV light source is still very important to overcome the stochastic effects for a higher throughput and higher numerical aperture (NA) in future. The required EUV power for the 3-nm node and beyond at the maximum throughput of future scanners is estimated to be more than 1 kW. We have designed and studied an EUV-FEL light source based on ERL for future lithography [1,2]. This light source offers many advantages such as high EUV power (> 10 kW), upgradability to a Beyond EUV (BEUV) FEL for finer patterning, polarization controllability for high-NA lithography, low electricity consumption and cost per scanner, as compared to the LPP source. Excellent high-power performance of the EUV-FEL light source was newly demonstrated by a start-to-end simulation with new optimization and more accurate calculation and conceptual schemes of upgrade to a BEUV-FEL, polarization control of the FEL light and an optical beamline to the scanners were proposed. Proof of concept (PoC) of the EUV-FEL light source using an IR-FEL constructed in the Compact ERL (cERL) at KEK is also in progress. In this presentation, we will present the EUV-FEL light source for future lithography including the PoC using the cERL IR-FEL.
Paper: THPM123
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPM123
About: Received: 30 Apr 2023 — Revised: 08 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
THPM125
High efficiency, 1 MW, 1 MeV accelerator for environmental applications
5157
We present design of a normal conducting, high efficiency linac that would provide a CW beam of 1 MW electrons at 1 MeV energy for various environmental applications. When a flowing sheet of wastewater is exposed to such a beam, various radiation-induced reactants are generated that lead to water purification by decomposing the chemical and biological pollutants therein. Such a linac could treat about 20 million gallons of wastewater per day with an ample dose of 1 kGy. Our linac comprises of three optimized accelerating rf cavities operating at 476 MHz. A compact rf distribution manifold splits the rf power from a 1-MW klystron in the appropriate ratio and phase for each accelerating cavity. The beam capture efficiency is 82% and the rf-to-beam efficiency is 94.5%. The total length of our accelerator is 2 m, which includes the 30 keV gun, the buncher cavity, and the accelerating cavities. In this paper, we present the corresponding beam dynamics, the implementation of rf couplers and feeding manifold, and the steady-state thermal analysis.
Paper: THPM125
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPM125
About: Received: 04 May 2023 — Revised: 10 May 2023 — Accepted: 23 Jun 2023 — Issue date: 26 Sep 2023
THPM127
Electron beam qualification at ENEA Frascati particle accelerators laboratory
5161
The APAM Laboratory of the ENEA Frascati Research Centre hosts two electron beam S-Band standing wave linacs. The older one, named REX, produces a 5 MeV, 150 mA electron beam with maximum PRF of 20 Hz. The second one, named TECHEA, was recently commissioned within a Research and Development program focused on breast radiotherapy applications: it produces a 3 MeV, 130 mA electron beam with maximum PRF of 100 Hz. Both plants can produce either electrons or X-rays through a conversion target with photon energies peaked at 2.5 and 1 MeV, respectively. In this contribution we report qualification activities on the electron beam properties in air (flux, uniformity and energy spectrum) at different target from source distances and at different extraction energies to assess the applicability of these facilities for multiple applications, such as sterilization, conservation of cultural heritage artifacts, material degradation, space components testing.
Paper: THPM127
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-THPM127
About: Received: 28 Apr 2023 — Revised: 09 May 2023 — Accepted: 19 Jun 2023 — Issue date: 26 Sep 2023
FRXD3
Commissioning and operation of the SPIRAL2 SC linac
5187
The SPIRAL2 linac is now successfully commissioned; H+, 4He2+, D+ have been accelerated up to nominal parameters and 18O6+,7+ and 40Ar14+ beams have been also accelerated up to 7 MeV/A.The main steps with 5 mA H+, D+ beams and with 0.8 mA 18O6+ are described. The general results of the commissioning of the RF, cryogenic and diagnostics systems, as well as the preliminary results of the first experiments on NFS are presented. In addition of an improvement of the matching to the linac, the tuning procedures of the 3 Medium Energy Beam Transport (MEBT) rebunchers and 26 linac SC cavities were progressively improved to reach the nominal parameters in operation, starting from the classical “signature matching method”. The different cavity tuning methods developed to take into account our particular situation (very low energy and large phase extension) are described. The tools developed for an efficient linac tuning in operation, e.g. beam energy and intensity changes, choice of the optics to obtain the requested beam parameters on target… are also discussed.
Paper: FRXD3
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-FRXD3
About: Received: 03 May 2023 — Revised: 04 May 2023 — Accepted: 11 May 2023 — Issue date: 26 Sep 2023
FRXG1
Prospects for future facilities based on energy recovery linacs
5193
Superconducting Energy Recovery Linacs (ERLs) promise a step change in the capabilities, and sustainability, of accelerator based facilities. This was highlighted in the 2022 ECFA/CERN European Strategy for Particle Physics Accelerator R&D Roadmap. Potential beneficiary fields include high energy particle physics, free-electron laser light sources for physical and life sciences and industry, and inverse Compton based gamma sources for nuclear science and industry. This talk will explore contemporary theoretical and experimental progress in ERLs, discuss the ongoing technical challenges, and present the community roadmaps toward deployment of ERLs in facilities globally.
Paper: FRXG1
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-FRXG1
About: Received: 03 May 2023 — Revised: 22 May 2023 — Accepted: 24 May 2023 — Issue date: 26 Sep 2023
FRYG1
European collaboration for the realization of ESS
5199
The European Spallation Source (ESS) linear accelerator, one the largest scientific equipment under realisation in Europe, is now in the beam commissioning stage. The project is implemented thanks to the collaboration of several European countries, mostly following the scheme of the in-kind contribution, with the involvement of scientists from many European laboratories and Universities in all phases, from design to beam commissioning. The most recent achievements are described in detail. The in-kind contributions are vast and differentiated, including delivery of normal conductive and superconducting accelerating structures, ion sources, magnets, power converters, RF systems, controls, diagnostics as well as the participation to design, installation, and commissioning of the linac. Results of this collaborative effort will be shown in details.
Paper: FRYG1
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-FRYG1
About: Received: 03 May 2023 — Revised: 11 May 2023 — Accepted: 15 Jun 2023 — Issue date: 26 Sep 2023
FRYG2
Accelerator driven system – a solution to multiple problems of society
5205
One of the greatest challenges for nuclear energy is how to properly manage the highly radioactive waste generated during irradiation in nuclear reactors. Accelerator Driven Systems (ADSs) is one methods of addressing the transmutation of such high level nuclear waste. ADS or accelerator driven transmutation of waste (ATW) consists of a high power proton accelerator, a heavy metal spallation target that produces neutrons when bombarded by the high power beam, and a sub-critical core that is neutronically coupled to the spallation target. This talk presents the world overview of nuclear energy that has proven to assist in dee-carbonization of energy sectors since the mid-1970s as well as the approaches to ADS being explored around the globe
Paper: FRYG2
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-FRYG2
About: Received: 12 May 2023 — Revised: 08 Jun 2023 — Accepted: 08 Jun 2023 — Issue date: 26 Sep 2023