vacuum
MOPC17
Operation of the LHC during the 2023 proton run
87
In 2023 the LHC restarted after the yearly winter shutdown with a new machine configuration optimized for intensities of up to 1.8e+11 protons per bunch. In the first two months of the 2023 run the bunch intensities were pushed up to 1.6e+11 protons per bunch until a severe vacuum degradation, caused by a damaged RF bridge, occurred close to the ATLAS experiment. Following repair, the decision was taken to stop the intensity increase. After a period of smooth operation, a leak developed between the cold mass and insulation vacuum of a low-beta quadrupole, leading to an abrupt stop of the LHC. Thanks to a rapid intervention, the leak could be repaired without warning up large parts of the machine, and the LHC was ready for beam again early September. Special runs at very large beta* were completed in the remaining time before switching to Lead ion operation. The performance achievements and limitations as well as the issues that were encountered over the year will be discussed in this paper.
Paper: MOPC17
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPC17
About: Received: 12 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPC77
Eddy current shielding of the magnetic field ripple in the EIC electron storage ring vacuum chambers
246
The EIC electron storage ring has very tight tolerances for the amplitude of electron beam position and size oscillations at the interaction point. The oscillations at the proton betatron frequency and its harmonics are the most dangerous because they could lead to unacceptable proton emittance growth from the oscillating beam-beam kick from the electrons. To estimate the amplitude of these oscillations coming from the magnet power supply current ripple we need to accurately account for the eddy current shielding by the copper vacuum chamber with 4-mm thick wall. At the frequencies of interest, the skin depth is a small fraction of the wall thickness, so the commonly used single-pole expressions for eddy current shielding transfer function do not apply. In this paper we present new (to the best of our knowledge) analytical formulas that adequately describe the shielding for this frequency range and chamber geometry and discuss the implications for the power supply ripple specifications at high frequency.
Paper: MOPC77
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPC77
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
MOPG30
Status update of the SASE3 variable polarization project at the European XFEL
364
The SASE3 Variable Polarization project is intended to offer polarization control of the X-ray FEL pulses at the European XFEL. The project was completed in early 2022. During the winter shutdown 2021-2022, all four APPLE-X helical undulators were placed in the tunnel and first lasing was achieved in April 2022. Unfortunately, further use of the helical afterburner proved impossible, as the encoders used to position the magnetic structures of the undulator were damaged by radiation. To carry out repairs, all undulators were removed from the tunnel in the summer 2022, and investigations were carried out to determine the cause of the radiation damage. This article presents measures taken to minimize further radiation damage in order to ensure the continued operation of the helical afterburner.
Paper: MOPG30
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPG30
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPR78
PHOtocathode Epitaxy and Beam Experiments laboratory at Cornell: current status and future work
630
High-efficiency alkali antimonide photocathodes degrade with little oxidation, making them hard to characterize and test outside their growth chamber. In this proceeding, we report on the design and performance of the PHOtocathode Epitaxy and Beam Experiments (PHOEBE) laboratory at Cornell University, where the growth, characterization, and testing of alkali photocathodes in vacuum has been successfully integrated. The growth of photocathodes is characterized in-situ by measuring the QE and by looking at the photocathode’s reflection high energy electron diffraction (RHEED) pattern. Once the desired photocathode is obtained, it is moved to a storage chamber to collect spectral response data, after which it is moved to the cryogenic emittancediagnostic beamline via a vacuum suitcase. A rapid cathode exchange system in the diagnostic beam can efficiently transfer alkali-antimonide photocathodes to beamline operation with little QE loss. Using this beamline, the mean transverse energy of the photocathode can be measured at various photoexcitation wavelengths in the visible spectrum and sample temperatures within 20 - 300 K.
Paper: MOPR78
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPR78
About: Received: 16 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
MOPR81
An overview of spin-polarized photocathode research at Cornell University
642
The development of a robust spin-polarized electron source capable of sustaining mA scale average beam currents in a photoinjector is critical for many future accelerator facilities such as the International Linear Collider (ILC). In this proceeding we overview the several efforts being carried out at Cornell towards this end, including: high current (>1 mA) gun tests of robust activation recipes of GaAs at the HERACLES beamline, the development and demonstration of GaN as a robust spin polarized source and Density Functional Theory (DFT) ab initio studies of alkali-antimonide photocathodes as potential spin polarized electron sources.
Paper: MOPR81
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPR81
About: Received: 20 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
MOPR82
Chemical robustness enhancement of negative electron affinity photocathodes through cesium-iodide deposition
646
Photocathodes at Negative Electron Affinity (NEA), like GaAs and GaN, allow for efficient production of spin-polarized electrons. When activated to NEA with cesium and an oxidant, they are characterized by an extreme sensitivity to chemical poisoning, resulting in a short operational lifetime. In this work, we demonstrate that deposition of a cesium iodide (CsI) layer can be used to enhance the dark lifetime of both GaN and GaAs photocathodes activated with cesium. The mechanism behind this improvement is investigated using X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscopy (AFM) techniques.
Paper: MOPR82
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPR82
About: Received: 17 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
MOPR83
Design and construction of the photocathode vacuum suitcase for CARIE test facility
650
This poster will discuss the design of the photocathode vacuum suitcase that we currently design and construct for the Cathodes And Radiofrequency Interactions in Extremes (CARIE) test stand. The CARIE test stand is built to test behavior of the high quantum efficiency photocathodes at strong fields. The semiconductor photocathodes must be grown and delivered to the photoinjector under ultra-high-vacuum (UHV) conditions in order to maintain their properties. This is typically done using portable UHV vacuum systems called vacuum suitcases. We will discuss the vacuum and photocathode handling design of the CARIE vacuum suitcase and the status of the suitcase construction and testing.
Paper: MOPR83
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPR83
About: Received: 15 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
MOPR84
Unusual electron emission characteristics of CeB6 cathodes
652
Thermionic electron guns that use borides of lanthanum or cerium as the electron emission surface are widely adopted for electron microscopes due to their high brightness. CeB6 cathodes are known for their high environmental durability and can be used up to a vacuum pressure of 1e-6 Pa. At MHI-MS, our company, we also adopt CeB6 cathodes in the C-band compact accelerating structure units we manufacture, and we have shipped dozens of units so far. As for the cathode assembly, we purchase Vogel-type cathodes and incorporate them into the thermionic electron guns. Before shipping, we bake the entire accelerating structure, including the electron gun, and confirm the electron emission characteristics. Recently, some of the procured cathodes have exhibited abnormal behavior, such as a decrease in electron emission as the vacuum pressure of the electron gun decreases. Analysis of the CeB6 crystal shows no significant differences between the normal and abnormal batches, and the cause is still unknown.
Paper: MOPR84
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPR84
About: Received: 13 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
MOPS15
Symplectic modeling of ALS-U bending dipoles using 3D magnetic field data
733
The Advanced Light Source Upgrade (ALS-U) is a 2 GeV high-brightness, nine-bend achromat storage ring, designed to reduce the natural emittance relative to the existing ALS by a factor of 20 for improved x-ray coherent flux and brightness. The upgrade includes the installation of an accumulator ring of the same energy as, and slightly smaller circumference than, the storage ring. The bending dipoles provide special challenges for accurate symplectic modeling, such as the combination of large sagitta and magnet narrow vertical aperture (in the accumulator ring) and overlapping fringe fields (in the main ring). We describe a procedure for the calculation of symplectic maps for the ALS-U dipoles using robust surface-fitting methods based on 3D finite-element field data, including a discussion of vector potential gauge choice and model-dependent effects on the lattice chromaticity.
Paper: MOPS15
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS15
About: Received: 14 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
MOPS21
Update on the beam-induced heating and thermal analysis for the EIC vacuum chamber components
755
One of the challenges of designing the Electron-Ion Collider (EIC) is to mitigate beam-induced heating due to the intense electron and hadron beams. Heating of the Electron Storage Ring (ESR) vacuum chamber components is mainly due to beam-induced resistive wall loss and synchrotron radiation. For the Hadron Storage Ring (HSR) components, heating is mainly due to resistive wall loss because of the large radial offset, electron cloud formation, and heat conduction from room temperature to cryo-components. In this paper, we provide an update on the beam-induced heating and thermal analysis for some EIC vacuum chamber components including the RF-fingers module of HSR cryogenic interconnect assembly. In addition, we provide simulation update for the HSR snake BPM, and abort kicker along with the change in ESR vacuum chamber profile. Similar analysis for other HSR and ESR components are available in Ref.~\cite{sangroulalocalized_NAPAC22, sangroula2023beam}. Our approach for thermal analysis involves calculating resistive wall losses using CST, evaluating heat loss due to synchrotron radiation and electron cloud formation and incorporating these losses into ANSYS for finding the temperature distribution.
Paper: MOPS21
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS21
About: Received: 16 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
MOPS22
Resistive wall heating and thermal analysis of the EIC HSR beam screen
759
The Electron-Ion Collider (EIC) utilizes the existing Relativistic Heavy Ion Collider (RHIC) rings as a Hadron Storage Ring (HSR) with some modifications. However, this presents significant challenges, primarily due to beam-induced Resistive Wall (RW) heating resulting from a larger radial offset and shorter EIC bunches (up to 10 times shorter than RHIC). Additionally, the formation of an electron cloud further complicates matters. To address these issues and operate the HSR effectively, this paper focuses on the RW heating and thermal analysis of the EIC HSR beam screen. Our approach involves the insertion of a copper-coated stainless steel beam screen with cooling channels and longitudinal slots. We conducted a detailed thermal analysis, assessing piecewise RW losses around the beam screen's profile due to an offset beam, employing the 3D commercial code CST. These losses, along with realistic boundary conditions, were then integrated into another code, ANSYS, to determine the thermal distribution.
Paper: MOPS22
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS22
About: Received: 18 May 2024 — Revised: 20 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
MOPS34
Incoherent and coherent tune shifts in Elettra 2.0
790
Elettra 2.0, will be a 4th generation synchrotron radiation source that will replace Elettra, the 3rd generation light source that has been in operation since 1993 at Trieste. In this paper, the effects of the quadrupolar wake fields are investigated, and the transverse mode coupling threshold is presented. Also, the incoherent tune shift for multi-bunch operation is examined considering the rhomboidal vacuum chamber of Elettra 2.0.
Paper: MOPS34
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-MOPS34
About: Received: 13 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
TUAN3
Understanding of the LHC warm vacuum module heating
947
During the third run of the Large Hadron Collider in 2023, which had the highest intensity bunch population compared to previous runs, increased losses attributed to pressure spikes within a warm vacuum sector triggered a beam dump. Subsequent inspections revealed localised annealing and plasticisation of the tension spring in the sliding contact radio-frequency finger module, alongside traces of vapour deposition on the various module components with the stainless-steel spring material. A comprehensive analysis involving vacuum and beam impedance studies was conducted to investigate the triggering mechanisms behind the radio-frequency finger module failure. The findings indicate localised beam-induced heating, which could lead to the annealing of the spring with a consequent cascade of effects. Additionally, investigations of potential mitigation measures were performed.
Paper: TUAN3
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUAN3
About: Received: 14 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
TUBN1
Multicell dielectric disk accelerating structure high power experiment results
963
A Dielectric Disk Accelerator (DDA) is a metallic accelerating structure loaded with dielectric disks to increase its shunt impedance. These structures use short RF pulses of 9 ns to achieve accelerating gradients of more than 100 MV/m. Single cell and multicell clamped structures have been designed and high power tested at the Argonne Wakefield Accelerator. During testing, the single cell clamped DDA structure achieved an accelerating gradient of 102 MV/m with no visible damage in the RF volume region. The minimal damage that was seen outside the RF volume was likely due to RF leakage from uneven clamping during assembly. Based on the success of that experiment, a clamped multicell DDA structure has been designed and tested at high power. Simulation results for this new structure show a 108 MV/m accelerating gradient with 400 MW of input power with high shunt impedance and group velocity. Engineering designs were improved from the single cell structure for a more consistent clamping over the entire structure. Up to this point in the high power experiments, the results show a peak input power of 222 MW correlating to an accelerating gradient of 80 MV/m. Testing of this structure will continue January 2024.
Paper: TUBN1
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUBN1
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUCN1
Vertical beam halo characterisation at the ESRF EBS for operation with reduced in vacuum undulator gap
973
The vertical beam halo is the main limitation for very low gap operation of in-vacuum undulators at the ESRF EBS. The vertical halo is due to Touschek electrons with large energy deviation crossing some betatron resonances. The crossing of the resonances can transfer horizontal momentum to vertical momentum. The beam halo has been characterized and measured and different low halo optics have been studied and tested to allow the operation of the machine with lower in-vacuum undulator gaps.
Paper: TUCN1
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUCN1
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
TUPC36
Initial operational experience of an LHC injection kicker magnet upgraded for HL-LHC
1080
The intensity of the HL-LHC beam will be twice that of LHC. Hence, an upgrade of the LHC injection kickers (MKIs) is necessary for HL-LHC to avoid excessive beam induced heating of the MKIs. In addition, any newly installed MKI magnet would limit HL-LHC operation for a few hundred hours due to dynamic vacuum activity. Extensive studies have been carried out to identify solutions to address these problems and they have been implemented in an upgraded LHC injection kicker magnet (MKI Cool): the MKI Cool was installed in the LHC during the 2022-23 Year End Technical Stop. Magnet heating has been reduced by redistributing a significant portion of the beam induced power deposition from the ferrite yoke to a ferrite loaded RF Damper, which is not at pulsed high voltage, and by water cooling of the damper. Furthermore, a surface coating, to mitigate dynamic vacuum activity, has been applied. This paper discusses the upgrades, presents results from the initial operational experience, and compares the predicted and ‘measured’ beam induced power deposition.
Paper: TUPC36
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPC36
About: Received: 12 May 2024 — Revised: 18 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
TUPC67
Progress in the design of the future circular collider FCC-ee interaction region
1156
In this paper we discuss the latest developments for the FCC-ee interaction region layout, which represents one of the key ingredients to establish the feasibility of the FCC-ee. The collider has to achieve extremely high luminosities over a wide range of center-of-mass energies with two or four interaction points. The complex final focus hosted in the detector region has to be carefully designed, and the impact of beam losses and of any type of synchrotron radiation generated in the interaction region, including beamstrahlung, have to be evaluated in detail with simulations. We give an overview of the progress of the whole machine-detector-interface-related studies, among which are the updated mechanical model of the interaction region, the plans for a novel R&D activity of a IR mockup which is just starting, the collimation scheme and evaluation of beam induced backgrounds in the detectors, evaluation of radiation dose in the experimental area, and MDI integration with the detector.
Paper: TUPC67
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPC67
About: Received: 14 May 2024 — Revised: 20 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPC72
Improvements of the SPS slow extraction electrostatic septum
1176
The impact of high-flux protons on the inherent beam loss in the slow extraction from SPS towards the North Area has been recently discussed and potential improvements have been proposed. These solutions are mainly aiming to reduce the high component activation and related reduction of lifetime, as well as observed non straightness in the anode body. Recent studies have allowed to demonstrate feasibility of replacing the currently installed stainless steel tank, flanges, and anode body by lowZ materials. The design iteration and material choice has led to the fabrication of a reduced length prototype, demonstrating mechanical, electrical, as well as the vacuum related performance. The mass reduction of the anode body has been optimized using numerical simulation, considering mechanical and thermal constraints. The paper presents the development of the vacuum vessel, including numerical analysis. The results from the design and prototype tank fabrication will be compared to the existing system. Furthermore, the optimization of the anode body and potential fabrication based on additive manufacturing including 3d optical straightness metrology will be discussed.
Paper: TUPC72
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPC72
About: Received: 15 May 2024 — Revised: 28 May 2024 — Accepted: 29 May 2024 — Issue date: 01 Jul 2024
TUPC73
Beam loss studies for the P42 beamline at the CERN SPS north area
1180
The P42 beamline transports 400 GeV protons from the CERN SPS between the T4 and T10 targets. A secondary particle beam is produced at the T10 target and transported along the K12 beamline to the experimental cavern ECN3, presently housing the NA62 experiment. In the context of the Physics Beyond Colliders (PBC) study, an increase of the beam intensity in P42 has been considered to provide protons to a future high-intensity fixed-target experiment in ECN3. For both its present usage and especially for the intensity upgrade, it is important to reduce beam losses to a minimum to decrease environmental radiation levels and protect equipment. In this study, simulations of P42 with the Monte Carlo software BDSIM, are used to demonstrate that beam losses in P42 are primarily driven by particle-matter interactions in material intercepted by the beam. The distribution of the simulated losses is compared to doses measured along the beamline in radioprotection surveys and beam loss monitors. Future mitigation strategies to reduce beam losses are then discussed and evaluated.
Paper: TUPC73
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPC73
About: Received: 14 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPC75
HL-LHC series collimators: key technical requirements, crucial production challenges and risk mitigation plan
1188
In view of High Luminosity (HL) - Large Hadron Collider (LHC) project, an upgraded collimation system has been developed to accommodate a rise of ten times of the integrated luminosity compared to the LHC. A new series of collimators will be produced and installed in the machine during the Long Shutdown 3 (LS3) to take place during 2026-2028. The updated design incorporates cutting-edge technologies to meet the demanding operating requirements. Multiple production activities are recognized as critical to ensure the quality of the collimators. Comprehensive qualification checks of the production procedures are planned, and functional tests will be conducted to validate the performance of each unit produced.
Paper: TUPC75
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPC75
About: Received: 14 May 2024 — Revised: 24 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
TUPG01
Dismantle, assembly and installation plans for the ALBA II upgrade
1217
The 3.0 GeV ALBA Synchrotron Light Source, in operation with users since 2012, is looking forward an upgrade aimed at enhancing the brightness and coherence fraction of the delivered X-ray beam. The Storage Ring (SR) will be completely renewed but we plan on keeping the same orbit length and the position of the ID source points. The energy of the electrons will be preserved and the same injector will be used. Major part of the Insertion Devices and Front Ends will be kept; new ones will feed additional long Beamlines (230m-275m), included on the project. The “dark period” is foreseen for 2030-2031. This paper presents the strategic plans being developed to test and assemble the new SR components, the dismantling of the present SR and the seamless installation of the upgraded SR. Emphasizing a cost-effective and time-efficient approach, we have started the planning by focusing on optimizing spaces and equipment movements necessary for the upgrade process.
Paper: TUPG01
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG01
About: Received: 10 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
TUPG06
Particle accumulator ring restart and readiness for Advanced Photon Source upgrade commissioning
1228
At the Argonne (ANL) Advanced Photon Source (APS), a 425-MeV Particle Accumulator Ring (PAR) is used to stack 1-nC electron pulses from the linac and inject a single bunch into the booster at a 1-Hz repetition rate. All the APS injectors, including PAR, were shut down in April 2023 at the start of the APS Upgrade Dark Time. In this paper, we report on PAR re-start activities starting in Oct. 2023. The PAR vacuum pressure was unexpectedly high when first powering the fundamental and harmonic radiofrequency (rf) systems, as well as when first injecting the beam, which initially limited both the beam charge and rf gap voltage. These limits were overcome through many weeks of systematic rf and vacuum conditioning. Additional restart activities include commissioning two new kicker chambers with a special low-impedance, eddy-current-suppressing coating, commissioning of the digital low level rf system, and tests with the Injection Extraction Timing and Synchronization (IETS) system. We demonstrated initial APS-U commissioning performance goals: a stable, 5-nC injected bunch charge with a bunch length short enough for injection into the booster.
Paper: TUPG06
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG06
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPG38
Design and construction progress of ALS-U
1313
The ALS-U project to upgrade the Advanced Light Source to a multi bend achromat lattice received CD-3 approval in 2022 marking the start of the construction phase for the Storage Ring. Construction of the accumulator under a prior CD-3A authorization is already well advanced. ALS-U promises to deliver diffraction limited performance in the soft x-ray range by lowering the horizontal emittance to about 70 pm rad resulting in two orders of magnitude brightness increase for soft x-rays compared to the current ALS. The design utilizes a nine bend achromat lattice, with reverse bending magnets and on-axis swap-out injection utilizing an accumulator ring. It is optimized to produce intense beams of soft x-rays, which offer spectroscopic contrast, nanometer-scale resolution, and broad temporal sensitivity. This paper presents the final design, prototype results as well as construction progress.
Paper: TUPG38
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG38
About: Received: 21 May 2024 — Revised: 21 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
TUPG56
Status of undulators for the APS upgrade
1376
The Advanced Photon Source Upgrade (APS-U) project has developed and installed a multi-bend achromat (MBA) lattice operating at 6.0 GeV beam energy to replace the existing APS storage ring lattice that operated at 7.0 GeV. A major part of the project is to install 60 hybrid permanent magnet undulator (HPMU) insertion devices (IDs) that include 12 revolver undulators, each with two magnetic structures (for a total of 72 magnetic structures); and one electromagnetic undulator for intermediate energy x-rays (IEX). These IDs will outfit 35 sectors. We have developed new HPMU designs for five different period lengths used in 46 magnetic structures, and we will reuse 26 existing magnetic structures with four additional period lengths. Eight new superconducting undulators (SCUs) have been designed and built with two short period lengths and three different overall lengths [1-3]. The SCUs will be installed in both inline and canted configurations after beam commissioning is completed and the user runs start. Demanding field requirements for the undulators were expected to be challenging for the undulator tuning, especially given the tight schedule. All undulators underwent rigorous tuning and control system tests before they were installed in the new storage ring. We will provide a status and schedule update including presenting measurement results of the IDs.
Paper: TUPG56
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG56
About: Received: 14 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
TUPG57
Design of an X-undulator
1379
The Advanced Photon Source Upgrade (APS-U) will deliver a new storage ring based on a Multi-Bend Achromat (MBA) lattice featuring swap-out on-axis injection, enabling the use of small diameter insertion device vacuum chambers. To leverage this advantage, we designed an X-undulator similar to the APPLE-X undulator but with a fixed gap and additional simpler magnet arrays for force compensation. The X-undulator is a pure permanent-magnet-based polarization variable undulator with a 30 mm period length and an 8.5 mm diameter bore in the beam center. The gaps between neighboring undulator magnetic arrays are 3 mm. Variation of the radiation wavelength and polarization is achieved using the longitudinal motion of the undulator magnetic arrays. This contribution covers the magnetic and mechanical design, as well as the optimization of this X-undulator.
Paper: TUPG57
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG57
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPG64
Integrated Hall probe and stretched wire measurement system for an in-vacuum undulator
1398
Taiwan Photon Source (TPS) is a 3 GeV synchrotron light source at the National Synchrotron Radiation Research Center (NSRRC) in Taiwan. Several in-vacuum undulators are expected to be installed before the end of 2024. Before installation in the storage ring, an in-vacuum undulator's magnetic field has been measured at operational gaps. In order to assess the performance of the in-vacuum undulator, we integrated two measurement methods in the vacuum chamber: one is the SAFALI (Self Aligned Field Analyzer with Laser Instrumentation) system to measure the magnetic field, and the other is the stretched wire system to measure the magnetic field integral. In this work, we designed a stretched wire measurement system integrated with the SAFALI system inside the vacuum chamber. This measurement system was applied to the in-vacuum undulator with a period of 22mm and a magnetic length of 2 m.
Paper: TUPG64
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPG64
About: Received: 08 May 2024 — Revised: 19 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
TUPR02
Advancements in X-band technology at the TEX facility at INFN-LNF
1421
In anticipation of the Eupraxia@SPARC_LAB project at the INFN Frascati National Laboratories, an intensive testing and validation activity for the X-band RF system has commenced at the TEX test facility. The Eupraxia@SPARC_LAB project entails the development of a Free-Electron Laser (FEL) radiation source with a 1 GeV Linac based on plasma acceleration and an X-band radiofrequency (RF) booster. The booster is composed of 16 high-gradient accelerating structures working at 11.994GHz. All radiofrequency components comprising the basic module of the booster, from the power source to the structure, must undergo testing at nominal parameters and power levels to verify their reliability. For this reason, since 2021, several experimental runs have been conducted to test various components in X-band technology at the TEX facility. This paper presents the results obtained thus far from the different experimental runs, and it also outlines the future upgrade of the facility, which will enhance testing capabilities and the future prospects of the facility itself.
Paper: TUPR02
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR02
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPR04
Preserving restoring and conditioning the RF cavities of the storage ring for the Advanced Photon Source upgrade
1425
The Advanced Photons Source (APS) storage ring (SR) underwent an upgrade to the multi-bend achromat (MBA) lattice recently. As part of the upgrade, four out of the sixteen Radio Frequency (RF) cavities were removed from the storage ring. The remaining twelve cavities were left in place during the entire upgrade process and restored to full operating power to support beam commissioning once the installation activities were completed. This paper provides details on the planning and preparations made to preserve the cavity integrity during the installation period, challenges faced while restoring the cavities and how the cavity power coupler beta values were determined.
Paper: TUPR04
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR04
About: Received: 15 May 2024 — Revised: 24 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
TUPR21
Influence of deposition parameters on the microstructure and vacuum properties of NEG-coated vacuum chamber
1460
The non-evaporable getter (NEG) coatings provide conductance-free evenly distributed pumping, low thermal outgassing rates, second electron yield, and photon-and electron-stimulated desorption. NEG coatings are crucial for achieving ultrahigh vacuum in fourth-generation diffraction storage ring vacuum systems. TiZrV thin films were deposited onto elongated CuCrZr pipes for this investigation. The influence of various deposition parameters on the microstructure and vacuum properties of NEG coatings was investigated. The microstructure, surface topography, roughness, and phase composition were evaluated using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Atomic Force Microscope (AFM), and X-ray Diffraction (XRD), respectively. Furthermore, the activation performance of the TiZrV films was investigated in relation to deposition parameters.
Paper: TUPR21
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR21
About: Received: 14 May 2024 — Revised: 17 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
TUPR28
LANSCE 805 MHz klystron reliability analysis
1486
Los Alamos Neutron Science Center (LANSCE) relies on 44 klystron modulator systems to feed the accelerating cavities and produce proton beam of 800 MeV. This paper focuses on the new VA-862A1 86kV 1.25 MW klystron units and aims to compare their performance with previously purchased units. Service hours for each klystron unit was used as the primary metric in the analysis and records from various sources cross-corroborated to confirm recorded information. Factors such as prior repair/rebuilds, factory acceptance tests and runtime notes were carefully inspected to provide a comprehensive view of the klystron performance during analysis. Klystron units currently being used in the LINAC were surveyed along with failed units and analysis performed to predict the next failure. The frequency and cause of failure was also compared with historical performance and failure data and results utilized for LANSCE SCCL performance optimization.
Paper: TUPR28
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR28
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
TUPR52
Injection magnet system for Korea-4GSR facility
1540
A 4th generation storage ring based light source is being developed in Korea since 2021. It features <100 pm rad emittance, about 800 m circumference, 4 GeV e-beam energy, full energy booster injection, and more than 40 beamlines which includes more than 24 insertion device (ID) beamlines. For extraction/injection to the booster and storage ring, it needs 4 septums, and 6 kickers. Particularly, for SR injection needs an eddy current septum with 1 mm septum thickness for 10 mrad bending, and a thick septum with 5 degree direct current driven septum. In this report, the design of the injection magnets (kickers, septums) for Korea-4GSR will be discussed.
Paper: TUPR52
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR52
About: Received: 16 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPR57
Stress-strain state analysis of the first-grade titanium foil of the accelerator output window in a static state
1560
The stress-strain state of the titanium foils of the accelerator output windows at various thicknesses was studied with the choice of first-grade titanium foil as a brand. The latter is more affordable and accessible compared to a second-grade titanium foil. The deformation diagram, density, Young's modulus, and Poisson's ratio of the first-grade titanium were selected as initial data. Atmospheric pressure was used as an external pressure, and the pressure from the vacuum side was taken as zero. The latter is acceptable in simulations of ultrahigh vacuum assemblies since it does not affect the overall picture of the stress-strain state. In addition to studying the central nodes of the metal foil, the sealing nodes were also considered as an object of research, with the study of stress intensity, meridional and circumferential stresses, and maximum displacements of the center. Based on the results, a function was obtained that allows us to accurately calculate the displacements of the center of the first-grade titanium foil depending on its thickness. The analysis of the received data was carried out.
Paper: TUPR57
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR57
About: Received: 03 May 2024 — Revised: 20 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPR59
The mechanical behavior of the EIC beam screen during a magnet quench
1568
As part of the Electron-Ion Collide (EIC) upgrade at Brookhaven National Laboratory (BNL), the development of new beam screens for the vacuum system is underway. The mechanical design of the beam screens received support from CERN, particularly in addressing the mechanical response during a magnet quench, i.e. a resistive transitions in the superconducting magnets. Maintaining an overall elastic behavior in this component is crucial for the efficient functioning of the collider. The mechanical behavior of the EIC beam screen during a quench was initially analyzed using analytical methods and subsequently validated through a Multiphysics FEM model developed for the High-Luminosity LHC (HL-LHC) beam screen. The FEM model underwent an initial verification against analytical formulations in its simpler 2D magnetic-based version. Following this, thermal and mechanical physics were fully coupled with the magnetic model in a 3D framework. Various features, including partial weld penetration, pumping holes, and guiding rings, were then taken into consideration. Additionally, the plastic behavior of the beam screen materials was considered too. The assessment included an analysis of the maximum deformation and stress experienced by the EIC beam screen during a magnet quench, resulting in an overall elastic response for the proposed design.
Paper: TUPR59
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR59
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPR61
Modification of TPS arc-cell vacuum system for installation of EPU66
1572
Modification of an arc-cell vacuum system (length 14 m) for the cell SR18 in the TPS storage ring is described, which includes (a) replacement of a new bending chamber (B1) with an increased vertical aperture from 9 to 18 mm to prevent the B1 chamber from being exposed to synchronous radiation from the upstream elliptically polarized undulator (EPU), and (b) incensement of three pairs of flanges to separate the old arc-cell vacuum system into four subsystems (S3, B1, S4, B2). In this paper, we will report the manufacturing processes, measurement data and vacuum tests of these vacuum chambers.
Paper: TUPR61
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR61
About: Received: 15 May 2024 — Revised: 17 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
TUPR62
Investigation of reduced baking time on dynamic pressure in a Taiwan photon source front end system
1575
The Taiwan photon source (TPS), a synchrotron accelerator at the National Synchrotron Radiation Research Center in Taiwan, is a third-generation accelerator operating at 3 GeV that was designed to create a high energy photon source. The TPS front-end (FE) systems are located between the storage ring and beamline, which was designed to protect the safety of users as well as control experimental requirements. As the FE vacuum pressure influences the storage ring and beamline vacuum pressures, the FE vacuum systems must maintain a low dynamic pressure. Therefore, at the beginning of FE system construction, each FE vacuum system is baked at 200°C for 24 hours. Next, when the FE systems need to be upgraded or maintained lead to vacuum interventions, it must also be baked for 24 hours to recover a low dynamic pressure. However, the 24 hour baking process requires manpower support on-site owing to facility safety in the TPS tunnel. The maintenance of the FE systems takes two duty days. Therefore, reducing baking time is necessary in the TPS facility. The beam cleaning efficiency after reduced baking time has been described in this paper.
Paper: TUPR62
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR62
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
TUPR64
Setup of Goubau Line system for impedance-measurement of vacuum components at the NSRRC
1578
A setup of in-house made Goubau (G-) Line system for measuring the broadband impedance of vacuum components has been developed at the NSRRC for improving the beam-stability of the Taiwan Photon Source (TPS). A thin copper wire of 0.287 mm in diameter with polyimide-coating ~0.02 mm in thickness connects two horn-shape aluminum launchers face-to-face at a distance ~1.2 m far in between via two impedance-matching copper tapers welded on both ends of the wire that transports the surface waves through the vacuum duct under test (DUT) allocated at the middle of wire. Measurement of time domain reflection (TDR) for the G-Line has verified the systematic performance of matching the impedance of 50 ohms. A vector network analyzer measures the transmission parameters of S21 of the DUT from the G-Line that the longitudinal impedance of DUT can be obtained. Various DUTs of vacuum components e.g. flanges without gasket were measured for inspecting the G-Line performance, besides, the special designed aluminum gaskets with rf-shielding property sealed flanges were also inspected that must feature with ultra-low impedance. The detail design and the test results of the G-Line will be described.
Paper: TUPR64
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR64
About: Received: 15 May 2024 — Revised: 16 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
TUPR70
Advanced charge selector for stripped heavy ion beams
1582
A new charge selector is currently under development at FRIB to intercept unwanted charge states of higher-power 17 - 20 MeV/u stripped heavy ion beams. The charge selector is located in the first bending segment of the FRIB linac, where high dispersion separates charge states to allow for their selection. The design concept is based on rotating graphite cylinders that act as an intermediate heat transfer medium, efficiently absorbing beam power and radiating it to a water-cooled heat exchanger. The power in the beam spot of up to 5 kW and the rms spot width as small as 0.7 mm present significant design challenges. Beyond thermal stress, the proposed design addresses the effects of radiation damage and implantation of the intercepted ions. The challenges of the engineering design associated with high temperatures, thermal expansion, rotation and linear actuation feedthrough into vacuum, as well as radiation shielding and remote handling, will be discussed. A comprehensive exploration of these challenges aims to contribute to the broader field of beam interception technology.
Paper: TUPR70
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR70
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
TUPR74
Magnetic measurement bench for a pulsed non-linear kicker based on vibrating wire
1586
Transparent off-axis injection in a storage ring by means of a non-linear kicker requires tight field tolerances at the limit of modern technique. To characterize the field profile of the non-linear kicker under development for the ALBA-II storage ring, a dedicated measurement bench based on a variant of the vibrating wire technique was developed. The small size and limited weight of the kicker magnet under study allows for some unusual solution which substantially simplify the set-up. Field mapping is obtained by scanning the magnet aperture, while keeping the wire steady, simplifying considerably the wire tensioning system. The wire is suspended vertically in a pendulum configuration eliminating the wire sagging problem and resulting in an inherently stable wire tension. Furthermore we investigate the possibility to characterize time dependent phenomena, such as the effect of eddy currents induced in the titanium coating of the magnet vacuum chamber, by using using an etherodyne approach where the magnet and the wire are excited by a continuous wave signal with period close to the characteristic kicker pulse period and differing in frequency by the wire resonance frequency
Paper: TUPR74
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR74
About: Received: 13 May 2024 — Revised: 20 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPR86
Exploring high gradient limit with cryogenic experiments at FREIA laboratory
1618
Field emission (FE) and vacuum arcs limit the maximum achievable accelerating field of both normal and superconducting cavities. The performance of accelerating cavities can be improved after a long conditioning process. Understanding this process and the formation of vacuum arcs is important for all technologies where vacuum arcs cause device failure. The understanding could be more complete with novel diagnostic tools and tests in variable environments. The cryogenic HV system in FREIA laboratory is used to study different aspects of conditioning using DC pulses at a wide range of temperatures, down to 4K. We are currently measuring FE currents during conditioning for Cu, Nb and Ti electrodes in function of temperature and breakdown rate. We are also developing a new characterization method, evaluating the surface resistivity of the electrodes during conditioning. Changes in the surface resistivity could indicate the formation of dislocations below the surface, which has been speculated to be a very important process behind conditioning. We will present the results of conditioning with the FE measurements and the surface resistivity measurements.
Paper: TUPR86
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPR86
About: Received: 15 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
TUPS13
SIS18 Operation with U²⁸⁺
1661
In SIS18 U²⁸⁺ is used to reach highest heavy ion beam intensities for FAIR-operation. The medium charge state avoids losses during stripping processes and shifts the space charge limit to higher number of particles. Nevertheless, these ions are subjected to ionization loss in collisions with residual gas particles. Via ion impact induced gas desorption a feedback between vacuum quality and beam emerges, yielding in a beam intensity limitation. The installation of a charge exchange collimator is one of the several upgrade measures which have been performed to shift this limit. They are equipped with a current measurement system to detect charge exchanged ions, which is routinely used during machine experiments. In this proceeding we present different beam based measurements showing dynamic vacuum effects. The non-linear dependence of the extraction intensity on the number of injected particles, ramp rate, and brake-time for vacuum relaxation will be shown. Stored heavy ion beams were used for charge exchange current measurements. They allow conclusions on the vacuum conditions and are presented as well.
Paper: TUPS13
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS13
About: Received: 08 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPS19
Development of high-power electron gun and collector for the new antiproton decelerator electron cooler
1680
The electron cooler of the Antiproton Decelerator (AD) at CERN was initially developed for the Initial Cooling Experiment in 1979. It was subsequently adapted for use at LEAR and is currently employed in the AD. However, certain components of the cooler are now more than 40 years old and lack spare parts. To ensure the reliable operation of the AD, a new electron cooler is under development. This presentation focuses on the development of the new electron gun and collector that will provide the 2.4 A / 27 keV electron beam. The process involves choosing the gun/collector design, informed by electron-beam simulations, which aim to achieve the lowest transverse temperature of the electron beam within the cooling section and the highest collection efficiency of the collector. Subsequently, the gun and collector undergo meticulous testing and characterization on a dedicated test bench. The design undergoes iterative refinement to address issues related to high voltage sparks, vacuum pressure, and electron losses. Distinguishing features of the new cooler that make it more reliable compared to its predecessor will also be discussed.
Paper: TUPS19
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS19
About: Received: 13 May 2024 — Revised: 24 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
TUPS34
Superconducting magnet string test for the SIS100 accelerator of FAIR
1718
The SIS100 accelerator, currently under construction in Darmstadt (Germany), consists of six arc and straight sections. Each of the six cryogenic arc sections comprises fourteen regularly repeating optical cells (lattice). Each standard cell includes two dipole magnets and two quadrupole units integrated in a quadrupole doublet module. The SIS100 String Test technically represents one standard cell of the arc section of the SIS100, terminated by and End Cap and a Bypass Line as a representation of the end of the arc section. The purpose of the SIS100 String Test is to validate all technical systems such as cryogenics, vacuum, interlock and quench detection and investigate their collective behavior. A wide spectrum of tests will be performed during cool down, powering at operational conditions and warm up. Additionally, the experience gained during the SIS100 String Test will be crucial for the installation, commissioning and operation of the SIS100. The planning, installation process and first experimental results of the String Test will be presented.
Paper: TUPS34
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS34
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
TUPS43
Optimization of a welding procedure for making critical aluminum welds on the LBNF absorber core block
1754
The LBNF Absorber consists of thirteen 6061-T6 aluminum core blocks. The core blocks are water cooled with de-ionized (DI) water which becomes radioactive during beam operations. The cooling water flows through gun-drilled channels in the core blocks. A weld quality optimization was performed to produce National Aeronautical Standard (NAS) 1514 Class I [1] quality welds on the aluminum core blocks. This was not successful in all cases. An existing Gas Tungsten Arc Welding (GTAW) Welding Procedure Specification (WPS) was fine tuned to minimize, in most cases, and eliminate detectable tungsten inclusions in the welds. All the weld coupons, how-ever passed welding inspection as per the piping code: ASME B31.3 Normal Fluid Service [2]. Tungsten electrode diameter, type, and manufacturer were varied. Some of the samples were pre-heated and others were not. It was observed that larger diameter electrodes, 5/32 in., with pre-heated joints resulted in welds with the least number of tungsten inclusions. It is hypothesized that thinner electrodes breakdown easily and get lodged into the weld pool during the welding process. This breakdown is further enhanced by the large temperature differential be-tween the un-preheated sample and the hot electrode.
Paper: TUPS43
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-TUPS43
About: Received: 30 Apr 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
WEPC31
Towards Elettra 2.0 - R&I preparation activities
2033
The “Dark Period” (DP), that is the final shutdown for the Elettra Storage Ring (SR) with its ancillary equipment and most of its beamlines, is scheduled to start on July 2nd, 2025. During the DP we will remove the complete SR lattice structure with annexed cabling, piping, and supports; the Service Area, where most of the equipment to operate the SR is installed, will be completely renovated; the majority of the photon beamlines will be removed, moved, updated or “brand-new” installed, causing the reconfiguration of a large part of the outer wall of the SR tunnel. Several activities are running in order to reduce the Removal and Installation (R&I) workload – already quite significant – during the DP. These activities are mostly related to the beamlines in the Experimental Hall and some shielding wall reconfiguration. The paper summarizes the most relevant activities done in preparation to the DP, with focus also on the logistics aspects related to the installation of a new machine while removing the old one (Elettra) being very closed to another operating one (FERMI).
Paper: WEPC31
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPC31
About: Received: 07 May 2024 — Revised: 17 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
WEPC50
GaAs cathode activation with Cs-CsO-Sb thin film
2076
GaAs cathodes are unique devices which generate a spin-polarized electron beam by the photoelectric effect when illuminated with a circularly polarized laser. Thin-film Negative Electron Affinity (NEA) surfaces have an essential role in spin polarized beam production, but they have limited lifetimes. In this study, we activate GaAs as an NEA cathode by evaporating Cs, Cs-O, and Sb metal on its cleaned surface. Here we present the latest experimental results of quantum efficiency measurements taken after evaporative deposition of multi-alkali thin-film surfaces.
Paper: WEPC50
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPC50
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPC55
A laser heated thermionic cathode
2090
There is increasing interest in developing accelerator technologies for space missions, particularly for fundamental science. In order to meet these mission needs, key accelerator technologies must be redesigned to be able to function more reliably and efficiently in a remote and harsh environment. In this work we focus on a modest electron injector system, specifically the traditional thermionic cathode. Typically such cathodes are resistively heated by a power supply that is floated at the cathode accelerating negative high voltage. This can increase engineering complexity and add a significant load to the accelerating voltage supply. We pursue laser heating a thermionic cathode in order to remove the heater power supply from the injector system, allowing for reduced engineering complexity and power requirements for the injector. To date we have shown that a simple tantalum disk cathode can be heated by a laser with similar emission performance to the same disk resistively heated.
Paper: WEPC55
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPC55
About: Received: 15 May 2024 — Revised: 17 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPC62
Development of new method of NEA Activation with Cs-Sb-O
2109
Negative Electron Affinity (NEA) activated GaAs photocathodes are the only one capable of generating spin-polarized electron beam larger than 90%. However, the NEA layer currently made from mainstream cesium (Cs) and oxygen (O) is chemically unstable, the NEA-GaAs photocathode has a rapid QE degradation over time or electron beam. As a result, it requires an operating vacuum pressure of 1e-9 Pa and has a short lifetime. Recently, a new NEA layer using heterojunctions with semiconductor thin film of alkali metals and antimony or tellurium has been proposed. The latest research shows that the NEA activation method using Cs-Sb-O is made by co-evaporation of Cs, O2 and Sb. However, the co-evaporation method has high demands on equipment. Therefore, in this work, we attempted to fabricate a Cs-Sb-O NEA layer using a separation evaporation method. Specifically, we attempted four recipes and successfully fabricated the NEA layer by Cs-Sb-O. We also evaluated the dependence of QE on Sb thickness and found that it is easy to form a NEA layer with 0.2 nm of Sb.
Paper: WEPC62
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPC62
About: Received: 09 May 2024 — Revised: 23 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
WEPC64
Towards operating low mean transverse energy (MTE) alkali antimonide photocathodes at Argonne Cathode Test-stand (ACT)
2116
The performance and scientific reach of advanced electron accelerator applications, such as particle colliders, x-ray free electron lasers, and ultrafast electron diffraction, are determined by beam brightness. The beam brightness is constrained by the quality of photocathodes and is associated with low Mean Transverse Energy (MTE) of photoemitted electrons. To meet the requirements for applications demanding a bright electron beam, photocathodes must exhibit ultrasmooth physical and chemical roughness, a long operational lifetime, and robustness under high applied electric fields and laser fluences. In this work, we present the development of an experimental setup for the growth and in-situ characterization of high-quality, low-MTE alkali antimonide photocathodes. Additionally, we describe the modifications made to the Argonne Cathode Test-stand (ACT) at the Argonne Wakefield Accelerator (AWA) Facility, necessary for studying the performance of alkali antimonide photocathodes under real photoinjector conditions.
Paper: WEPC64
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPC64
About: Received: 15 May 2024 — Revised: 24 May 2024 — Accepted: 24 May 2024 — Issue date: 01 Jul 2024
WEPC73
Preparation, transport, and operation of high quantum efficiency semiconductor Cs₂-Te photocathode for SHINE
2140
According to the high repetition rate, high brightness and other operating characteristics of SHINE, the photocathode with high quantum efficiency, low emittance, and long operating lifetime is required to produce high-quality electron beam. After solving the problems of ultra-high vacuum acquisition, photocathode plug in vacuum transmission, and photocathode preparation process, the Cs-Te photocathode prepared on SHINE's photocathode preparation device based on Te intermittent and Cs continuous deposition method has a quantum efficiency greater than 10% under 265 nm light irradiation, and the quantum efficiency remains almost unchanged in the photocathode preparation device, photocathode suitcase, photocathode load lock system, and electron gun.
Paper: WEPC73
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPC73
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPG03
The RF BPM pickup and feedthrough testing results in the lab and SR for APS-U
2176
The BPM feedthroughs were manufactured and tested at the vendor and the APS lab. All feedthroughs were sorted in groups of four according to their capacitance. Four feedthroughs with close capacitance were welded to the housing in an assembly. The assemblies were measured in the APS lab to confirm their electrical performance acceptable and their x/y offsets were calculated according to VNA data. After the BPM assemblies were installed in the SR, they were measured again to verify their connections. The x/y offsets including the cables were compared with the previous data and will be used as the reference in beam commissioning. The testing results at the vendor, APS lab and APS-U SR were analyzed.
Paper: WEPG03
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG03
About: Received: 15 May 2024 — Revised: 18 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
WEPG39
Ionization profile monitors for the IOTA proton beam
2299
We present the design details and outline the construction progress of the Ionization Profile Monitors (IPMs). Two IPMs, designed for transverse beam size measurements of 70 MeV/c protons, are slated for installation—one horizontal and one vertical—in the IOTA ring. These IPMs are fast (1.8 microsecond, one turn), accurate (to better than 10%) and non-destructive diagnostics. They will play a pivotal role in facilitating comprehensive beam studies, particularly in investigating the dynamics of space-charge dominated proton beams in IOTA.
Paper: WEPG39
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG39
About: Received: 11 May 2024 — Revised: 20 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPG61
Electromagnetic bench testing of ALS upgrade beam monitor buttons and assemblies
2365
The ALS Upgrade Project (ALS-U) consists in the replacement of the existing ALS storage ring and the addition of a new accumulator ring in order to decrease the horizontal beam emittance to about 70 pm·rad, resulting in an increase of two orders of magnitude in the soft X-Ray brightness. The vacuum chambers of two new rings, and of the transfer lines connecting them, will include 327 new beam position monitors (BPM). The design of these BPM is now largely completed and relies on the procurement of about 1,500 BPM buttons (including spares and prototypes) from commercial suppliers and their installation on the BPM chamber enclosures. Our design includes more than a dozen different BPM designs and almost as many different buttons. All the buttons, as well as the assembled BPM, have to undergo vacuum and RF testing to characterize them and detect defective units before their installation. In this paper, we describe our electromagnetic testing plan and report on the results covering the entire button production for the accumulator ring and the prototypes for the storage ring, as well as the electromagnetic measurement for the assembled ALS-U Accumulator Ring (AR) BPMs.
Paper: WEPG61
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG61
About: Received: 16 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
WEPG66
Effects of delta ray electrons on measurement uncertainties of harp system
2378
A harp system, which is a multi-wire beam profile monitoring (MWPM) system, is planned upstream of the spallation target to make in situ calibration of beam current density configuration on the target along with beam imaging from luminescent coating on the beam entrance window at the Second Target Station (STS) of the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). This beam interception-based beam diagnostics system on the target will be used to ensure that the maximum beam loads on the target are within the design range during neutron production. Current design of the harp consists of three layers of measurement wires each of which is sandwiched between voltage biasing wire planes. The signal obtained from each measurement wire layer is disturbed by secondary electrons (SE) and delta rays produced by beam-matter interactions in neighboring wires and ionization of residual gases in accelerator vacuum. While the backgrounds from SE can be suppressed by voltage biasing, the delta-ray electrons with kinetic energies above keV ranges overcome the electric potential bias. In this paper, we study the effects of delta-rays on the measurement uncertainties of MWPM using the particle transport simulation code FLUKA. Furthermore, the cases where the harp system is installed in the proximity of a large delta ray sources such as proton beam window or in the core vessel filled with sub-atmospheric gas have been studied.
Paper: WEPG66
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG66
About: Received: 15 May 2024 — Revised: 19 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
WEPG86
Gas jet dosimeter measurements at DCF for medical accelerator applications
2418
Achieving non-invasive in-vivo dosimetry is a critical objective in the field of ion beam therapy. The comprehensive real-time characterization of the ion beam is highly desirable to ensure the safety of patients, treatment precision, and the efficiency of the treatment facility. However, current methods have limitations in terms of the information they provide and can be invasive to the beam. This contribution focuses on the development of a non-invasive, gas jet-based in-vivo dosimeter for use in treatment facilities. This technique relies on a non-disruptive interaction of a low-density supersonic gas jet curtain with the primary treatment beam. An existing gas jet monitor-based ionization profile monitor was modified and coupled with the accelerator beamline at the Dalton Cumbrian Facility (DCF), UK (United Kingdom). The aim of the test was to conduct proof-of-concept measurements for the profile and dosimetry of beams having characteristics similar to the medical treatment facilities. Measurements were carried out for proton and carbon beams of varied sizes, energies, and currents. The results obtained from these measurements demonstrated the feasibility of such a dosimeter and are instrumental for its improvement. This contribution introduces the design of the adapted gas jet dosimeter, discusses the findings from the measurements, highlights the dosimetry challenges addressed and outlines the scope of improvement for an online non-invasive gas jet in-vivo dosimeter.
Paper: WEPG86
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPG86
About: Received: 09 May 2024 — Revised: 17 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
WEPR33
Innovative bulge test setup to characterize thin beam vacuum windows
2560
As part of the International Muon Collider study, a beam vacuum window is being developed at CERN. It is required for the final cooling, where the charged particles travel from the vacuum chamber to the absorber; here, the beam loses momentum to cross a second window entering in a RF cavity that increases the longitudinal momentum. The best absorber for the final cooling is hydrogen. As the absorber should be installed inside a high field focusing solenoid, the hydrogen density should be as high as possible, ideally liquid or high pressure gas, to have a reasonable solenoid length. To evaluate the performance of the window, it is necessary to study the tightness at cryogenic temperatures, resistance to burst, high temperature and beam-induced damage. The main objective of the proposed work is to design and validate a versatile bulge test setup for the mechanical characterization of thin windows at different pressures and temperatures to cover all operating conditions, from 77 K to 293.15 K and ideally above. Due to the low thicknesses, a non-contact measuring technique based on a confocal chromatic sensor is proposed.
Paper: WEPR33
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPR33
About: Received: 14 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
WEPS09
Niobium-tin as a transformative technology for low-beta linacs
2709
Niobium-tin has been identified as the most promising next-generation superconducting material for accelerator cavities. This is due to the higher critical temperature (Tc = 18 K) of Nb3Sn compared to niobium (TC = 9.2 K), which leads to greatly reduced RF losses in the cavity during 4.5 K operation. This allows two important changes during cavity and cryomodule design. First, the higher Tc leads to negligible BCS losses when operated at 4.5 K, which allows for a higher frequency to be used, translating to significantly smaller cavities and cryomodules. Second, the reduced dissipated power lowers the required cryogenic cooling capacity, meaning that cavities can feasibly be operated on 5-10 W cryocoolers instead of a centralized helium refrigeration plant. These plants and distribution systems are costly and complex, requiring skilled technicians for operation and maintenance. These fundamental changes present an opportunity for a paradigm shift in how low-beta linacs are designed and operated. Fabrication challenges and first coated cavity test results are discussed.
Paper: WEPS09
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS09
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
WEPS14
Progress on high power FPC development for EIC
2727
The Electron-Ion Collider (EIC) requires 34, 500 kW continuous-wave (cw), 591 MHz Fundamental Power Couplers (FPCs) to compensate the Electron Storage Ring’s (ESR) 10 MW of synchrotron radiation and other beam driven losses. This paper will describe the FPC design and fabrication status, particularly the technical challenges associated with 500 kW cw operation and the innovative design addressing this. Of important note, the RF window based on 99.5% purity alumina window was designed to be wide operating bandwidth, which makes it applicable to FPCs for the EIC’s RF systems outside of the ESR with frequencies ranging from 197 MHz-591 MHz. This results in significant savings by eliminating the need to design multiple different RF windows for the different RF systems. This paper will describe the design and prototype progress of the High Power FPC for EIC.
Paper: WEPS14
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS14
About: Received: 09 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPS17
Low RF loss DC conductive ceramic for RF windows
2733
Charging of RF windows has historically been problematic, frequently resulting in damage to the window severe enough that the window needs to be replaced. Many attempts have been made to prevent charging and therefore improve window lifetime, the most successful and common of which is coating the window with titanium nitride (TiN). Surface coatings such as TiN rely on the secondary electron yield of the coating material being lower than that of the ceramic window material, reducing the number of electrons emitted from a variety of mechanisms. An alternative approach is to introduce a small amount of DC conductivity to the ceramic itself, turning the traditionally insulating window into a mildly conductive one. This allows any charge on the surface of the window to drain rather than build until a discharge happens. A magnesium titanate ceramic has been developed with a small DC conductivity and used to make RF windows. Several window assemblies have been produced and tested, including 1.3 GHz waveguide and 650 MHz coaxial designs. The results of the conductive ceramic window test program will be presented.
Paper: WEPS17
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS17
About: Received: 16 May 2024 — Revised: 20 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPS19
ESS installation progresses
2736
The ESS Linac on-going installation and technical commissioning are progressing towards the first operation at 870 MeV on the beam dump in fall 2024. Four out of five DTL tanks were commissioned with beam in the normal conducting section (NCL) and a pilot installation of 1 spoke and 1 elliptical cryomodule was conducted in the superconducting (SCL) part of the ESS tunnel in spring 2023. Regarding the latter, the goal was both to demonstrate the installation sequence as well as the completion of the cryogenic distribution system (CDS) commissioning. A total of 13 spoke and 14 elliptical cryomodules (9MB + 5HB) are being installed. Overall, 30 elliptical cryomodules will be necessary to allow the 5 MW potential power after the target commissioning. The CM test plan along with the installation of the necessary RF power stations up to the 2 MW stage for the first project phase is advancing well.
This contribution will report on the deliveries from the In-kind partners, SRF activities at the ESS test stands including the resolution of non-conformities and focus on the installation and technical commissioning of the linac components.
Paper: WEPS19
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS19
About: Received: 20 May 2024 — Revised: 21 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
WEPS21
Coupler HV bias studies on ESS elliptical cavities
2743
We study the effects of high voltage DC bias on the fundamental power couplers of the ESS elliptical SRF cavities. These tests were carried out at the TS2 facility, where cryomodule acceptance and characterization tests are carried out. We present the observed effects of positive and negative bias field on multipacting in the RF couplers, as well as the implications for operation in the ESS linac.
Paper: WEPS21
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS21
About: Received: 17 May 2024 — Revised: 18 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
WEPS41
Design, construction and operation of a surface-treatment platform for SHINE superconducting cavities
2785
The SHINE project requires more than six hundred 1.3GHz cavities and sixteen 3.9GHz cavities for the superconducting accelerator. These cavities are from both domestic and foreign companies. The cavities fabricated in domestic companies requires correspond-ing capacity of surface-treatment. For the R&D of surface-treatment technology and mass production of SRF cavities, we have been constructing a new surface-treatment platform near Shanghai for SHINE project. In this paper, we report the design, construction, commissioning and operation of this platform.
Paper: WEPS41
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS41
About: Received: 15 May 2024 — Revised: 16 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
WEPS67
Status of coil-dominated discrete-cosine-theta quadrupole prototype for high rigidity isotope beams
2854
Iron-dominated superconducting magnets are one of the most popular and used design choices for superconducting magnetic quadrupoles for accelerator systems. While the iron yoke and pole tips are economic and effective in shaping the field, the large amount of iron also leads to certain drawbacks, namely, unwanted harmonics from the sextupole correctors nested inside of quadrupole iron pole tips. Additional problems include the nonlinear field profile present in the high-field regime caused by the presence of steel, the cryogenic design challenges of the iron yoke being part of the cold mass, and the mechanical challenges of mounting the sextupole and octupole, which will generate significant forces for apertures of the size being proposed. The Facility for Rare Isotope Beams is developing a coil dominated quadrupole as a future upgrade, and the presented work discusses the advantages of using an iron-free quadrupole, along with the methods and choices of the design and the current status of prototype fabrication. The methods and work presented will include the model results and the aspects of the model that have been verified up to the current status of prototype fabrication.
Paper: WEPS67
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-WEPS67
About: Received: 15 May 2024 — Revised: 22 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THAN1
Design, realization and high power RF test of the new brazed free C band photo-gun
2929
RF photo-gun are the electron beam sources of FELs or Compton facilities. They are key components and, presently, the RF technology mostly used for these devices is the S band (3 GHz) with typical cathode peak fields of 80-120 MV/m and repetition rates lower than 100-120 Hz. An innovative C-Band (5.712 GHz) RF gun aiming at reaching cathode peak field larger than 160 MV/m, with repetition rates exceeding the 400 Hz, has been designed, realized and high power tested in the context of the European I.FAST and INFN Commission V projects. It is a 2.5 cell standing wave cavity with a four-port mode launcher, designed to operate with short RF pulses (300 ns). Its realization is based on the new brazed-free technology developed and successfully tested at INFN. In the paper, after a short overview of the design and RF gun capabilities, we illustrate the realization procedure and the results of the high power RF tests that have been done at the high power C band test facility at PSI (Switzerland).
Paper: THAN1
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THAN1
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THBN3
Lifetime of non-evaporable getter thin films over repeated activation
2960
Non-evaporable getter (NEG) coatings are used in accelerator beamlines to create an area of distributed pumping, allowing less external pumps to be installed, and smaller diameter tubes to be used. Both giving way to greater space for magnet arrays to better control the beam within, allowing more efficient accelerators to be produced. To work, NEG coatings must be activated by heating to a set temperature for 24 hours. This temperature depends on the properties of the NEG coating, and requirements of the system. The coating is then able to pump residual gasses out of the vacuum system, until it becomes saturated and will once again need activating. Over its a lifetime, a NEG coating will be activated and saturated numerous times, each time reducing the available sites for molecules to diffuse to during activation. Thus, eventually, the NEG coating will lose its capability, and will no longer be able to reach the same pumping capacity from the same activation regime. This study investigates the limits of NEG lifetimes, looking at the effect of multiple activations on the same coating. Samples of diameter 35 mm and length 50 cm were characterized by CO and H2 injections, from which the sticking probabilities and NEG coating capacity could be obtained. The samples were activated numerous times to see any degradation of the NEG coating. The results will be presented and discussed at IPAC 2024.
Paper: THBN3
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THBN3
About: Received: 15 May 2024 — Revised: 18 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
THPC46
Comparison of simulation and measurement of an in-vacuum undulator coupling impedance at NSLS-II
3098
The impedance of in-vacuum undulators (IVU) is a significant part of the total broadband impedance determining collective effects of beam dynamics in synchrotrons. It is computationally difficult to simulate the full few-meter-long 3D structure, which includes bellows, flanges, and taper transitions with a variable gap. So, the impedance is usually calculated separately for a simplified geometry of every component and the resistive-wall impedance is calculated using analytical formulas. The ECHO3D code based on a low-dispersive numerical technique provides an opportunity to compute the wakefield induced by a very short bunch in the full 3D model of the NSLS-II IVU. Here, we discuss the numerical simulations in comparison with beam-based measurements.
Paper: THPC46
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPC46
About: Received: 10 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
THPC47
Beam based measurements of titanium coated ceramic chambers at NSLS-II
3101
We summarize recent experimental studies of the impedance and beam-induced heating of titanium-coated ceramic vacuum chambers used in the NSLS-II injection kickers. We installed a spare chamber (SN003) in test section C01, demonstrating that beam-induced power is effectively dissipated in the titanium coating. Equipped with 12 temperature detectors, we measured temperatures and beam currents during operational fill patterns. The results, highlighting the heating of chamber, will be thoroughly presented.
Paper: THPC47
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPC47
About: Received: 07 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
THPC48
Impedance calculation for the hadron storage ring in the Electron-Ion Collider with ECHO3D
3104
ECHO3D has been used for calculating the geometric impedance for several beamline vacuum components in the hadron storage ring (HSR) of the EIC (Electron-Ion Collider) in the past few years. In this paper, we present the geometric impedances calculated from ECHO3D for the beam screen with pump slots, the polarimeter and the bellow with pump ports in the HSR. We also discuss some findings while cross-checking these results with what calculated from GdfidL and CST.
Paper: THPC48
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPC48
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPC58
Narrowband impedance studies in the HEPS storage ring
3144
The High Energy Photon Source (HEPS) is a fourth-generation synchrotron radiation facility with design beam emittance of less than 60 pm. Impedance modelling is an important subject due to the adopted small beam pipe as well as the tight requirements from beam collective effects. Narrowband impedances can be generated by the discontinuity of the vacuum chamber or the finite conductivity of the beam pipe. The coupled bunch instabilities caused by the narrowband impedances could restrict the beam current or perturb the synchrotron radiations. In this paper, the narrowband impedances in the HEPS storage ring are investigated element by element.
Paper: THPC58
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPC58
About: Received: 14 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
THPC61
Estimation of impedances and corresponding instabilities in Korea-4th generation storage ring
3155
Due to the small vacuum apertures, impedance serves as a significant cause of beam instabilities in the 4th generation storage ring. These instabilities are directly affected by the bunch charge, thereby placing a limit on the maximum achievable beam current within the storage ring. The Korea-4th generation storage ring (Korea-4GSR) is currently under construction with the aim of reaching a maximum beam current of 400 mA. To meet this goal, we've conducted estimations and optimizations of the current storage ring’s impedance. In this presentation, we show the impedance of Korea-4GSR and the corresponding instabilities.
Paper: THPC61
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPC61
About: Received: 19 May 2024 — Revised: 22 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPG17
Prototype control system for the Low Energy Branch ion beamline
3285
At the tandem ion accelerator laboratory of the Jožef Stefan Institute (JSI) in Ljubljana, Slovenia we are developing a control system for the Low Energy Branch (LEB) ion beamline. This activity is ongoing simultaneously with the hardware construction of the ion beamline branch dedicated to the research with low-energy ion beams with energies up to 30 keV. The LEB instrumentation is categorized into: a) Ion sources, b) Ion beam transport optics, and c) Accessories, including specialized detector systems and devices, used to prepare and maintain optimal experimental conditions. Therefore, key functionalities of the control system include the control of devices like vacuum pumps, power supplies, etc., data acquisition from sensors and detector systems, and ensuring reliable autonomous operation for high-precision physics experiments [1]. The control system will be implemented within the Experimental Physics and Industrial Control System (EPICS) environment [2], providing us with the tools required to develop a comprehensive and scalable control system. In this work, we present a block scheme, a device list, the prototype control system architecture of a minimal control system prototype currently operational in our laboratory.
Paper: THPG17
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG17
About: Received: 15 May 2024 — Revised: 19 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPG29
A multi-variable approach to mid-ranging control for unified operation of fast and slow correctors in fast orbit feedback system
3314
Advanced Photon Source Upgrade (APS-U) Fast Orbit Feedback (FOFB) system uses 160 fast and 160 slow corrector magnets to stabilize orbit measured at 560 Beam Position Monitors (BPM). We plan to operate both fast and slow correctors in a unified feedback algorithm at 22 kHz correction rate. Mid-ranging control is a proven approach for feedback systems with two manipulated inputs each exerting distinct dynamic effects to regulate a single output. This method resets the fast input to its chosen DC setpoint and proves beneficial when cost of fast input is more than the slower one. Unified operation of fast and slow correctors is a fitting application to mid-ranging concept which is well founded for two input one output systems. In this work, based on the cross-directional nature of the FOFB system we developed a multi-variable approach to mid-ranging control. It can be applied to FOFB with multiple fast and slow correctors, and multiple BPMs. Performance of proposed scheme is tested in simulations with APS-U FOFB prototype model in MATLAB. The feedback loop with fast and slow correctors is stable with mid-ranging algorithm, and the fast corrector drives effectively tracked setpoints.
Paper: THPG29
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPG29
About: Received: 16 May 2024 — Revised: 21 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPR05
The LOEWE-3 RFQ project
3485
The IAP (Institute for Applied Physics) of the Goethe University Frankfurt has a long experience in the development of 4-Rod RFQs. In the course of a project funded by the HessenAgentur as part of LOEWE funding line 3, the basic design of the 4-rod RFQs is now to be further developed. The aim is to investigate whether an improvement in Q-Value and vacuum can be achieved through new production and construction methods, as well as through fundamental adjustments to the basic geometric structure of the 4-Rod RFQ design. The project is divided into two phases. In the first phase, a simulation model is created in which all necessary changes that affect the RF characteristics of the RFQ are analysed. Based on these results, a demonstrator will then be built on which the innovations can be tested and any improvements examined. This article presents the basic ideas behind the project and the current planning status. This paper shows the basic ideas of the project as well as the current state of planning.
Paper: THPR05
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR05
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
THPR07
Preparation for the conditioning of the MYRRHA CH-Cavities at IAP
3491
The Institute for Applied Physics (IAP) installed a permanent test setup for up to \SI{60}{\kilo\watt} of RF power in cw mode for conditioning. The goal is to establish a time efficient test procedure for the future MYRRHA CH-cavities. Three test stands were designed to accommodate up to three cavities simultaneously. All stations are curently tested via the \SI{175}{\mega\hertz} MAX RFQ prototype at IAP with the new test setup. Vacuum, Low-level-, and high-power measurements have been successfully performed.
Paper: THPR07
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR07
About: Received: 15 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
THPR10
RF conditioning of an IH-DTL cavity made using additive manufacturing
3501
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. We present the most recent results of vacuum, low level RF, as well as RF conditioning of the cavity.
Paper: THPR10
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR10
About: Received: 14 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
THPR13
Conditioning of rod-style RFQ in support of LANSCE front-end upgrade
3508
The Los Alamos Neutron Science Center (LANSCE) front-end injection scheme requires an upgrade to a Radio-Frequency Quadrupole (RFQ) in order to replace the obsolete Cockroft-Waltons used in present operation. A test stand using a rod-style RFQ is under development in support of this upgrade, and conditioning of the RFQ to the expected peak and average power levels was completed to ensure its feasibility. The RFQ conditioning also revealed thermal issues with the RF power coupler and issues in managing the power reflected from the RFQ. These issues and their mitigation will be discussed in light of the capability of the test stand, and future plans will also be discussed.
Paper: THPR13
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR13
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
THPR16
Design of a spin rotator for the ISIS Super-MuSR beamline
3520
The spin rotators (SR) are DC electromagnetic devices that produce a homogeneous magnetic field to rotate the spin of the muons in flight, which is counterbalanced by a matched perpendicular electric field to avoid the bending of the muon beam trajectory. Two identical SR will be used in the new Super-MuSR beamline to rotate the muon spin by up to 34º per device relative to the beam direction, enabling higher transverse field muon measurements and other experiments not currently possible in the present ISIS MuSR beamline. The fundamental electromagnetic (EM) design of the SR is presented in this paper, both for the magnet and the high voltage vessel. The optimization of the electric and magnetic fields shape and strength is presented including fundamental hand calculations, 2D/3D models and particle tracking simulations. The high voltage feedthroughs and the electrode insulating supports were thoroughly designed to reduce the breakdown probability. A sensitivity study was also developed to estimate the manufacturing tolerances, but it is not presented in this paper.
Paper: THPR16
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR16
About: Received: 30 Apr 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
THPR17
Dimensional and thermal design of the electrostatic chopper for the new ISIS MEBT
3524
The electrostatic chopper for the new ISIS MEBT is a fast deflecting device to create gaps in the beam coming out of the RFQ, which will improve the trapping efficiency when injecting the beam into the ISIS synchrotron. The electromagnetic design of the chopper was initially developed to define its functional specifications, shape and dimensions, and it was presented elsewhere. A dimensional sensitivity study was developed to estimate the maximum acceptable thermal loads due to the beam loss (used later in the thermal model) and to ensure that the electric field shape and strength were still valid. Dimensional tolerances were defined based on the sensitivity study. Thermal calculations and models were required to ensure that the electrodes were properly cooled for the expected beam loss in the diverse working and failure situations, and to ensure that the hot beam dump inside the chopper was not indirectly overheating the electrodes. The mechanical design and manufacturing were carried out according to the results from the previous analyses, and the details are presented elsewhere.
Paper: THPR17
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR17
About: Received: 30 Apr 2024 — Revised: 16 May 2024 — Accepted: 16 May 2024 — Issue date: 01 Jul 2024
THPR18
Mechanical design of a QWR cavity for the new ISIS MEBT
3528
The Quarter Wave Resonator (QWR) is a longitudinal bunching cavity for the MEBT section of the Pre-injector Upgrade project at ISIS. Four cavities are required with at least one functional spare. The production of a full scale prototype is discussed here. Three main manufacturing challenges were encountered as follows: the tight manufacturing tolerances of the stainless steel tank, most noticeably the 80 µm tolerance along the length of the 370 mm bore; the 50 µm ± 10 µm copper plating layer on the inside of the complex geometry cavity; and the brazing of the copper lid to a long (280 mm) stem with the use of a jig, to achieve a tight precision in the length inside the cavity. Trials for all these have been conducted before being accurately assembled with a CMM, with lessons learnt and the final solutions presented.
Paper: THPR18
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR18
About: Received: 02 May 2024 — Revised: 17 May 2024 — Accepted: 17 May 2024 — Issue date: 01 Jul 2024
THPR19
Practical design and manufacturing of the new ISIS MEBT chopper
3532
The electrostatic chopper for the new ISIS MEBT is a fast deflecting device which will create gaps in the beam coming out of the RFQ, which will improve the trapping efficiency when injecting the beam into the ISIS synchrotron. The fundamental design (including electromagnetic and thermal calculations, and sensitivity studies) are presented elsewhere. The practical aspects of the mechanical design and the assembly of the prototype chopper are presented here. This includes how challenges were resolved, such as insufficient transmission from the fiber thermocouples through the feedthroughs, ease of life design features, such as the use of o-ring screws, tests performed to feed into the analytical design and the promising progress made to date.
Paper: THPR19
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR19
About: Received: 13 May 2024 — Revised: 17 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
THPR23
Towards mitigation of challenges in development of high power ISOL targets
3542
Worldwide Isotope Separation On-Line (ISOL) facilities face growing demand for producing and extracting high-purity exotic radioactive ion beams to serve nuclear physics, astrophysics and medical applications. In this technique, a particle beam interacts with a suitable target material to produce the desired isotopes through a combination of mechanisms like spallation, fragmentation and fission. TRIUMF has the world's highest-power ISOL facility—ISAC, handling 50 kW of proton beam power. The formidable challenge is to suitably handle the power deposited within the target material and maintain it at 2000°C to optimize the diffusion and effusion of the radioactive products. The intricacy of this design requires precise knowledge of the thermal properties of the target material. Typically, a blend of metallic carbide and graphite, these targets exhibit varying porosity and morphology and have effective thermal properties differing from individual constituent elements. To investigate these properties, a combined numerical-experimental approach is employed. This contribution discusses the optimization of target material sample size using numerical tools and outlines the exploration of thermal properties using an experimental apparatus, the Chamber for Heating Investigations (CHI), developed at TRIUMF.
Paper: THPR23
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR23
About: Received: 15 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPR29
High fidelity numerical modelling and condition monitoring applied to septum magnets at CERN
3556
The CERN Accelerator Beam Transfer group has recently launched a study to investigate the life cycles of pulsed septum magnets. The development is aiming to enhance the prediction of anomalies, leading to reduced life cycles of these beam transfer equipment. For this reason, the standard vacuum operated, direct drive septa magnet has been chosen to investigate critical design features. In the initial project phase, a so called High-Fidelity (HF) numerical simulation has been carried out, providing insight on critical components, like brazed joints, reducing the fatigue life. In parallel a dedicated test setup with state-of-the-art instrumentation has been developed, allowing to confirm the predicted system response. The novel approach for the beam transfer equipment will allow to review presently established design criteria. In a further iteration, the project is now aiming to demonstrate an anomaly detection and their prediction based on novel machine learning techniques. This paper presents the initial phase of developing the HF model, as well as the results of the instrumented magnet tests which will be compared to results from the numerical simulations.
Paper: THPR29
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR29
About: Received: 14 May 2024 — Revised: 17 May 2024 — Accepted: 18 May 2024 — Issue date: 01 Jul 2024
THPR64
Design of cyclotron-based in-vacuum material irradiation beamline at TINT
3671
A new cyclotron facility has been constructed at Thailand Institute of Nuclear Technology to provide proton beams with energy of 15-30 MeV for radioisotope production and material analysis. Due to requirements of particle induced X-ray emission (PIXE) and particle induced gamma-ray emission (PIGE) techniques that need a low-energy and low-intensity proton beam in range of 2-15 MeV and picoamperes as well as high detection sensitivity, the additional setup including an energy degrader, a collimator, a 30-degree separator magnet, and a slit, is employed for an in-vacuum irradiation beamline. In this work, we study the proton beam trajectory and beamline elements. The energy degrader made of aluminum has shown promising results in decreasing the beam energy while the energy spread of a secondary beam is significantly reduced by the following 30-degree separator magnet. Furthermore, the combination of the collimator and the slit lessens the beam current to proper values. To measure the proton beam current downstream, a copper Faraday cup will be used.
Paper: THPR64
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPR64
About: Received: 12 May 2024 — Revised: 16 May 2024 — Accepted: 16 May 2024 — Issue date: 01 Jul 2024
THPS01
STAR High-Energy Linac status: complete installation acceptance tests
3718
The installation of the STAR High-Energy Linac, the energy upgrade of the Southern European Thomson Back-Scattering Source for Applied Research (STAR) project at the University of Calabria, was conducted by INFN by the end of 2023. This paper presents the testing procedures aimed at confirming the consistency, completeness, and quality of the STAR accelerator upgrade installation (electron beam energy boost from 65 MeV up to 150 MeV). We illustrate the installation and testing of the electrical, hydraulic and related automation and auxiliary systems. We will discuss the high-power commissioning of the two C-band RF power stations and testing of the low-level C-band RF system and control system configuration based on EPICS. Finally, we will describe the layout and testing of the vacuum system, the characterization and commissioning of the magnets with related power supplies and the assessment of the installed diagnostics devices. The linac commissioning as well as electron beam measurements are planned for Summer 2024, due to pending radioprotection authorizations.
Paper: THPS01
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS01
About: Received: 15 May 2024 — Revised: 20 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024
THPS17
New insertion devices for BRIGHT beamlines at the Australian Synchrotron
3765
In 2016 the Australian Synchrotron embarked on the BRIGHT program to build four new insertion device beamlines: Biological Small Angle X-ray Scattering (BioSAX), High Performance Macromolecular Crystallography, Advanced Diffraction and Scattering and Nanoprobe beamlines. To maximize the flux for these very demanding beamlines, cryogenic and short period devices have been selected. In particular a 1.6 m long 16 mm period superconducting undulator, a 3 m long 18 mm period cryogenic undulator (CPMU), 3 m long 17 mm in-vacuum undulator and a 2 m long 48 mm period superconducting wiggler. This report will discuss some of the design considerations and overall parameters of the new insertion devices.
Paper: THPS17
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS17
About: Received: 16 May 2024 — Revised: 21 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
THPS22
Design study of a compact superconducting undulator based on laser-structured HTS tapes
3781
Undulators are X-ray sources which are widely used in synchrotron storage rings or in future light sources such as free-electron lasers. Due to sustainability and energy efficiency the development envisages small-scale high-field and compact undulators with short period lengths (<10 mm) and narrow magnetic gaps (<4 mm). Therefore, high-temperature superconducting (HTS) tapes, which can provide both large critical current densities and high critical magnetic fields, are widely used and investigated at KIT. A new concept of superconducting undulators (SCUs) was introduced and further developed by laser-scribing a meander pattern into the superconducting layer to achieve quasi-sinusoidal current path through the tape. In this contribution, we present our results from the design study in respect of the cooling concept for a compact SCU. The foreseen cooling is based on the one hand on calculations of the different heat loads through synchrotron radiation, impedance, and current supplies and on the other hand on the design of the liner including the tapering.
Paper: THPS22
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS22
About: Received: 15 May 2024 — Revised: 21 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
THPS25
Improving the uniformity of magnetron sputtering titanium film for nonlinear injection kicker
3791
The design and manufacturing of the Nonlinear Injection Kicker is one of the upgrade project for the Taiwan Photon Source (TPS). In accordance with the requirements of the developed ceramic vacuum chamber, it is necessary to apply a uniform titanium coating on the inner surface of the ceramic substrate to reduce the impedance and image current observed by the stored electron beam. Therefore, titanium films must be sputtered onto a 30 cm × 6 cm ceramic substrate, and these films must exhibit excellent uniformity. Based on our tests of sputtering titanium films on ceramic substrate, the uniformity of the titanium film can be controlled within 5%. The adhesion between the ceramic substrate and the titanium films meets the highest level of ASTM-D3359 5B standard, with an adhesive strength reaching 40 MPa. This paper describes the detailed manufacturing processes and testing results.
Paper: THPS25
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS25
About: Received: 05 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
THPS27
Development of a cryogen free MgB2 high temperature superconducting undulator
3797
RadiaBeam is designing and manufacturing a 15-mm period, 1.15 T field superconducting undulator. Realizing these parameters require a small gap, on the order of 5 mm. This small gap imparts a thermal management challenge due to heating from resistive walls, wakefields, upstream dipoles, and particle losses which is challenging to overcome with NbTi or NbSn3 wires without the use of liquid helium. Further, to reduce operating costs and reliance on liquid helium infrastructure, this undulator is designed to run off cryocoolers. In order to provide sufficient thermal overhead for cryocooling capacities, we will utilize Magnesium Diboride (MgB2), a metallic superconductor with a transition temperature at around 39 K. Thermo-mechanical engineering design studies and production plans of our prototype will be presented.
Paper: THPS27
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS27
About: Received: 14 May 2024 — Revised: 21 May 2024 — Accepted: 21 May 2024 — Issue date: 01 Jul 2024
THPS35
A novel pulse compressor with dielectric assistance
3813
A compact pulse compressor with dielectric assistance structure is proposed and simulated. The novel pulse compressor adopts a spherical resonant cavity design with dual-mode polarization mode. A dielectric sphere added at the centre of the spherical cavity can reduce the volume and weight of the pulse compressor and improve the unloaded quality factor of the cavity. A C-band compact storage cavity model is designed and simulated on ANSYS HFSS working on 5.712 GHz. The dielectric permittivity of the dielectric sphere is 9, and the dielectric tangent loss is 0.00001. The simulation of the dielectric-assist resonant cavity with an inner diameter of 34 mm indicates an unloaded quality factor about 72000.
Paper: THPS35
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS35
About: Received: 14 May 2024 — Revised: 20 May 2024 — Accepted: 20 May 2024 — Issue date: 01 Jul 2024
THPS40
Thermal-fluid analysis and operation of a low power water-cooled tilted beam dump at Facility for Rare Isotope Beams
3823
The Facility for Rare Isotope Beams is a high power heavy ion accelerator completed in April 2022. The FRIB accelerator was commissioned with acceleration of heavy ions to energies above 200 MeV/nucleon (MeV/u) that collide onto a rotating single-disk graphite target. The remaining beam is absorbed by a water-cooled static beam dump that is oriented at a 6 degrees angle with respect to the beam. The beam dump consists of the beam stopper made of machined Aluminum 2219 block, and 3D-printed inlet and outlet parts made of Aluminum 6061 that delivers the cooling water from utilities to the beam stopper and its return. This low power beam dump is designed for up to 10 kW beam power. This paper presents a discussion on the thermal-fluid behavior of the beam dump for various beam species and beam power.
Paper: THPS40
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS40
About: Received: 13 May 2024 — Revised: 19 May 2024 — Accepted: 19 May 2024 — Issue date: 01 Jul 2024
THPS44
Diffusion bonding of tungsten-vanadium-zirconium using vacuum hot pressing for the development of a low decay heat cladding solution for tungsten spallation targets
3837
Tantalum has been used as cladding material for water-cooled solid tungsten targets at many leading spallation neutron production facilities thanks to its high neutron yield, manageable radiation damage behavior, and excellent corrosion/erosion resistance in radiation environments. However, from a safety hazard perspective, thermal neutron capture of tantalum in spallation environments causes a high specific decay heat in the target volume, which often becomes a limiting factor in increasing the beam power on the target. In this paper, we studied vacuum hot pressing (VHP) parameters to diffusion bond zirconium to tungsten to explore the feasibility of using zirconium alloys as an alternative cladding material to tantalum. Zirconium alloys have long been used as cladding material for early generation solid spallation targets, and nuclear fuel rods. In spallation environments zirconium has significantly lower decay heat with shorter decay time compared to tantalum. The hot isostatic pressing (HIP) of zirconium and tungsten is known to produce limited bonding quality due to the formation of the brittle ZrW2 intermetallic layer. To overcome this problem, placing a vanadium interlayer between tungsten and zirconium has been proposed by exploring parameter space in binary alloy phase diagrams. Under the VHP conditions, 860 ◦C at 70 MPa for 4 hours, Zr-V and V-W showed good diffusion bonding, which demonstrates the feasibility of a single step HIP process to make the zirconium alloy clad tungsten spallation volumes.
Paper: THPS44
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS44
About: Received: 15 May 2024 — Revised: 19 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
THPS62
Perspectives and recent achievements on additive manufacturing technologies for accelerators
3890
This paper reports the exploratory studies on advanced accelerator technologies performed within the I.FAST (Innovation Fostering in Accelerator Science and Technology) EU project, and in particular the key results of the additive manufacturing Task 10.2 – “Additive Manufacturing – applications and potential developments” and Task 10.3 – “Repair of damaged accelerator components by AM technologies”. This includes results of two surveys targeted to the accelerator community: a) on current additive manufacturing applications in accelerators and expected new developments, b) on current additive manufacturing repair technologies for accelerator and list of possible applications. The paper is outlining potential additive manufacturing applications in accelerators and overall strategies applicable to accelerator components repairs benefiting from additive manufacturing technology.
Paper: THPS62
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS62
About: Received: 18 May 2024 — Revised: 22 May 2024 — Accepted: 22 May 2024 — Issue date: 01 Jul 2024
THPS63
Relationship between anisotropy and cross rolling process for high purity niobium sheets
3893
The standard fabrication method for superconducting cavities is to press high RRR niobium sheets to form half cells, which are then joined by EBW (electron beam welding) to form cavities. If the anisotropy of the niobium sheet is too large, gaps will form when the half-cells are joined, so a sheet with low anisotropy is required. To reduce the anisotropy of the sheet, it is essential to apply cross-rolling during fabrication. In this experiment, three types of sheets were produced with different reduction rates during TSCR (Two Sep Cross Rolling). Then, the average anisotropy coefficient r ̅ and planar anisotropy Δr, the evaluation criteria of anisotropy, were compared to find a relationship between anisotropy and cross rolling condition. As a result, it was found that the Δr value was the smallest and the in-plane anisotropy was the smallest when the reduction ratio before and after cross rolling was the same. In addition, half cells of superconducting cavities were press formed using three types of niobium sheets, and the roundness of the equatorial part was measured. There was no difference among the three types.
Paper: THPS63
DOI: reference for this paper: 10.18429/JACoW-IPAC2024-THPS63
About: Received: 14 May 2024 — Revised: 23 May 2024 — Accepted: 23 May 2024 — Issue date: 01 Jul 2024