bluuebunny/crossref_metadata_2025_split huggingface dataset:
New controls for White Circuits power supplies for the booster synchrotron of Taiwan light source
Authors: Liao C Y , Wu C Y , Cheng Y S , Chen J , Lee D , Hu K H , Hsu K T 
Published: January 2024

Abstract
The controls of the White Circuits for the booster synchrotron of Taiwan Light Source (TLS) were developed in the late 1990s. That design is based on various analog circuitry to detect 10 Hz magnet amplitude and phase. The existing implementation consists of analog regulation for amplitude control and digital regulation for the relative phase between magnet families. Recently, modernized White Circuits controls were implemented to prevent component obsolescence in the existing system. The upgraded system adopts digital regulation for both amplitude and phase loops. Improve performance and easy maintenance are the goals of this upgrade.
Development of a new control interface for the electron gun pulser of TLS Linac
Authors: Liao J K , Lee D , Cheng Y S , Wu C Y , Hu K H , Hsu K T 
Published: January 2024

Abstract
The electron gun control system, which serves as the TLS LINAC’s power source, has been in operation for more than two decades. Since some components of a previously designed circuit have aged and been discontinued, the control system will become unreliable and irreparable. A new control interface of electron gun pulser has been developed to improve the operational stability and future maintenance of the electron gun control system. To achieve remote control, an SBC (single-board computer) equipped with a high-precision AD/DA expansion board was used as a control interface. The signal processing circuit module generates the bias and b-plus voltages that are output to the electron gun and also provides instant feedback voltage readings. For easier maintenance, the new electron gun pulser control modules have been assembled into a single box. Furthermore, this software architecture of control interface has been based on the EPICS framework and integrated with an existing TLS control system. The efforts of rejuvenating electron gun pulser control system are described in this paper.
Stability analysis of double-harmonic cavity system in heavy beam loading with its feedback loops by a mathematical method based on Pedersen model
Authors: Shen Y B , Gu Q , Jiang Z G , Gu D , Zhu Z H 
Published: January 2024

Abstract
With the high beam current in storage ring, it is necessary to consider the instability problem caused by the heavy beam loading effect. It has been demonstrated that direct RF feedback (DRFB), autolevel control loop (ALC) and phase-lock loop (PLL) in the main cavity can lessen the impact of the beam effect. This paper regarded the beam, main cavity, harmonic cavity and feedback loops as double harmonic cavity system, and extended the transfer functions in the Pedersen model to this system. Some quantitative evaluations of simulation results have been got and conclusions have been drawn. In the case of a passive harmonic cavity, the optimization strategy of the controller parameters in the pre-detuning, ALC and PLL, as well as the gain and phase shift of DRFB were discussed. Meanwhile, it also involved the impact of the harmonic cavity feedback loop on the system stability at the optimum stretching condition when an active harmonic cavity was present. The research results can be used as guidelines for beam operation with beam current increasing in the future.
Test stand for conditioning high power tetrodes at TRIUMF
Authors: Avreline N V , Zvyagintsev V , Gregoire D , Piletskiy K 
Published: January 2024

Abstract
A major part of the 520 MeV Cyclotron’s RF system is the high-power RF amplifier. The amplifier is based on eight 4CW250,000B tetrodes. A new high-power tetrode or a high-power tetrode that underwent refurbishing could trip the RF system through inner sparks. The likelihood of those sparks should be reduced prior to applying nominal power to the new and refurbished tetrodes. This could be achieved by RF conditioning of these tetrodes on a test stand. The test stand represents a 150 kW RF amplifier loaded by a dummy load. The amplifier is built using common grid schematics. The test stand’s output stage incorporates the 4CW250,000B tetrode that is under test. This paper describes the mechanical and electrical designs of the test stand, procedures of testing and conditioning for 4CW250,000B tetrodes, and the results of test stand’s commissioning.
Bimodal design of 500MHz and 1.5GHz normal conducting RF cavity for advanced synchrotron radiation facilities
Authors: Su Dinghui , Tan Janhao , Fang Wangcheng , Wang Cheng 
Published: January 2024

Abstract
The advanced storage ring light source needs to realize ultra-low emissivity beam operation, and improving the Touschek lifetime puts forward higher requirements for the performance of RF cavity. In this paper, a novel bimodal normal conducting RF cavity is proposed. In one cavity, two power sources will be connected at the same time to realize the simultaneous operation of the two frequencies. The TM010 mode with the frequency of 500 MHz is used for acceleration, and the TM020 mode with the frequency of 1.5 GHz is used as the third harmonic to improve the height of the RF bucket and achieve the purpose of lengthening the beam bunch. Two couplers are designed to adapt to the working characteristics of bimodal RF cavity.
Magnetic Alloy Core Loaded 2nd harmonic cavity design and testing for CSNS-II RCS
Authors: Wu Bin , Li Xiao , Nie Xiao Jun , Zhang Chun lin , Liu Yang , Long Wei , Li Xiang , Wu Jian 
Published: January 2024

Abstract
In this report, we present our recent progress in the design and high-power testing of the 2nd harmonic cavity for the China Spallation Neutron Source upgrade project. To achieve optimal performance, high-performance magnetic alloy (MA) cores with dimensions of Φ850mm × Φ316mm × 25mm were meticulously developed and fabricated to serve as the load material for the radio-frequency (RF) cavity. Through rigorous testing, we were able to achieve a remarkable cavity accelerating gradient of over 40 kV/m under 15% duty cycle. To ensure optimal cooling efficiency, we conducted a comprehensive fluid dynamics simulation analysis and verified our results through experiments. Finally, to assess the long-term stability and performance of the cavity, we conducted a series of extended operation tests. These experiments successfully confirmed the high-performance capabilities and exceptional stability of the 2nd harmonic cavity.
Improved waveforms for Barrier-Bucket systems
Authors: Breitkreutz B , Stassen R 
Published: January 2024

Abstract
Barrier-Bucket (BB) systems provide a method to apply a short gap to a coasting beam. This is utilized for different applications, like ion cleaning, or to compensate the medium energy loss caused by internal experiments. BB-cavities are broadband cavities, and the applied signal is commonly a short sine burst, followed by a flat section at zero voltage. Since the transfer function of the BB-system is usually neither flat nor linear, it is common to predistort the signal to obtain the desired shape at the rf gap. Nevertheless, the resulting waveform still has a ripple in the flat section. This is due to the lowpass characteristic of the amplifier and the sharp edges at the ends of the sine, which lead to an infinite number of harmonics. This paper provides better suited BB-waveforms, which are designed with a finite number of harmonics from the beginning. It is shown that a much better flatness can be achieved than for a conventional BB-waveform, without sacrificing any performance. These advanced waveforms are currently used at the hadron synchrotron COSY at Forschungszentrum Jülich, leading to improved BB-bunch shapes, in particular for electron-cooled beams.
Electrodeposition of copper on niobium for cryocooler application
Authors: Prudnikava A. , Tamashevich Y. , Kugeler O. , Knobloch J. 
Published: January 2024

Abstract
The electrodeposition of copper onto niobium using commercial acidic and alkaline electrolytes was tested. The continuous dense polycrystalline copper films were successfully obtained in aqueous alkaline-type bath containing copper sulphate, sodium hydroxide and sodium gluconate. The effect of benzotriazole and sodium lauryl sulphate additives on the morphology and crystal structure of the deposited copper was investigated by optical and scanning electron microscopy, and X-ray diffraction. No copper oxides were found in the grown films. Copper films had moderate adhesion properties that would be insufficient for cryocooler application. We are currently exploring different compositions of electrolyte baths for obtaining the coatings on niobium with improved adhesion.
Status and upgrades of radio frequency system at Taiwan Photon Source
Authors: Chang M H , Lo C H , Yu T C , Liu Z K , Chung F T , Chang F Y , Chang S W , Chen L J , Li Y T , Yeh M S , Wang Ch , Lin M C 
Published: January 2024

Abstract
In order to meet the upcoming RF power requirements of TPS, a five-year upgrade project to construct a new RF station was completed in early 2022. This new RF station mainly consists of an SRF module, a 300-kW SSPA, an analog LLRF control system, RF transmission components, and accessary cooling systems. Test results of the SRF module and 300-kW SSPA met the expected performances. Also presented are the operation statistics of the two original RF stations and the ongoing upgrades. Meantime between RF failures during TPS user time reached 600 hours in 2022, while the construction and tests on DLLRF control system, power combination of klystron and SSPA, and 2-cell 1.5-GHz SRF module have all progressed well.
Conceptual design of multipole injection kicker magnets for the ILSF storage ring
Authors: Azami Z , Saeidi F , Tafrihi A , Ahmadi E , Noori K 
Published: January 2024

Abstract
The standard injection scheme of the Iranian Light Source Facility(ILSF) is composed of 2 septum and 4 kicker magnets installed in a 7-meter-long straight section. Further tuning of the 4 kicker devices to reduce perturbations has proven to be almost impossible since it requires having 4 identical magnets, electronics and Ti-coated ceramic chambers. Different from pulsed dipole kicker magnets used in a conventional local-bump injection, a single nonlinear or multipole kicker provides a nonlinear distribution of magnetic fields, which has a maximum value off the axis where the injected beam arrives and a zero or near-zero value at the center where the stored beam passes by. So, here the designs of different multipole kickers, including sextupole, octupole and a nonlinear kicker, have been investigated and compared.
Development of a New Electromagnetic Extraction Channel from the AGOR Cyclotron
Authors: Kremers H R , Jones B N , Smit H A J , Gerbershagen A , Brandenburg S 
Published: January 2024

Abstract
The extraction system of the superconducting AGOR cyclotron consists of an electrostatic deflector and three electromagnetic channels. As the electrostatic deflector has only a moderate field strength (<100 kV/cm), the first electromagnetic channel (EMC1) has to generate a rather strong dipole component resulting in current densities up to 169 A/mm2 in water-cooled copper coils. In the original design the coils consist of sections of hollow conductors, parallel to the beam path, vacuum-brazed to machined “bridges” over the beam aperture. Altogether there are over 200 brazed joints made in three subsequent cycles in the three coils (dipole, quadrupole and first harmonic corrector). In 25 years of operation two channels of this type have been “consumed”. The channels developed water leaks due to erosion of the copper by the high speed cooling water flow in the “bridge” regions that ultimately could not be repaired anymore. To remedy this problem the channel has been redesigned using bent conductors. A production technique for small radius bends and a new joining method to avoid vacuum brazing have been developed. The coil support taking up the 10 kN/m Lorentz forces on the windings are now made from isolating material instead of anodized aluminium to prevent grounding errors. The new channel (EMC1-U) has been in operation now for two years without any failure. A detailed comparison of the old and new design will be presented.
High-Power Modular GaN Based Power Supply for MedAustron Scanning Magnets
Authors: Margreiter T , Gadner T , Incurvati M , Teixeira R A , Cesaris I De , Pelletier S 
Published: January 2024

Abstract
MedAustron is a synchrotron-based ion therapy center in Wiener Neustadt, Austria, constantly working towards the performance improvement of cancer treatment. A major improvement opportunity comes from the scanning magnets system – a crucial element of dose delivery system at MedAustron - that is influenced by the bandwidth and power density of the magnet power supplies. Therefore, a novel highly modular power converter, based on the latest gallium nitride technology is being developed to tackle the aforementioned requirements. One sub-module of this power supply is based on two H-bridges that are operated in hard parallel and are integrated into a standardized euro-crate form factor with target output power specifications of 720 kW. This design also includes a 4th-order output Bessel filter to meet the ripple requirements for clinical operation. Furthermore, those sub-modules offer the possibility of being connected, cascaded or interleaved, in order to meet different output power requirements, providing a high modularity aspect. The status of this development in terms of requirements, global topology, and control structure is presented.
Measurement of the Photoelectron Yield from the Synchrotron Radiation for the NEG-coated Tubes
Authors: Hsiung G Y , Cheng C M , Valizadeh R 
Published: January 2024

Abstract
NEG-coated chambers have been adopted as the beam ducts for large particle accelerators and synchrotron light sources for the sake of the lower yields of the photon stimulated desorption (PSD) and the photoelectrons (PE) from the NEG films in addition to their pumping performance. Measurement of the photoelectron yield (PEY) was performed at the BL19B (PSD) beamline of the 1.5 GeV Taiwan Light Source (TLS) which simultaneously measures the PSD-yield. An aluminium cathode was inserted in the tubes and a positive bias of voltage for extraction of the photoelectrons applied. The PEY was obtained by dividing the photoelectron current by the photon flux of the synchrotron radiation. Measurements of the PEY include various types of NEG-coated stainless steel tubes and the bare tubes of titanium and aluminium alloys for the comparison. The experimental system and the results will be described in this presentation.
RF Characterisation of Laser Treated Copper Surfaces for the Mitigation of Electron Cloud in Accelerators
Authors: Krkotić P , Calatroni S , Himmerlich M , Neupert H , Perez-Fontenla A T , Wackerow S , Abdolvand A 
Published: January 2024

Abstract
In accelerator beam chambers and RF waveguides, electron cloud and multipacting can be mitigated effectively by reducing the secondary electron yield (SEY). In recent years, it has been established that laser-engineered surface structuring is a very efficient method to create a copper surface with a SEY maximum close to or even below unity. Different laser pulse durations, from nanoseconds to picoseconds, can be used to change surface morphology. Conversely, the characteristics that minimise the SEY, such as the moderately deep grooves and the redeposited nanoparticles, might have unfavourable consequences, including increased RF surface resistance. In this study, we describe the techniques used to measure the surface resistance of laser-treated copper samples using an enhanced dielectric resonator with 12 cm diameter sample sizes operating in the GHz range. The quantification basis lies in a non-contact measurement of the high-frequency losses, focusing on understanding the variation of surface resistance levels depending on the specifics of the treatment and possible post-treatment cleaning procedures.
Elettra 2.0: The Vacuum System Design for a New Generation Storage Ring
Authors: Novinec L. , Loda G. , Scrimali G. , Cudin I. , Rumiz L. 
Published: January 2024

Abstract
Next-generation synchrotron facilities currently under development and construction are promising and delivering great advances in terms of machine design and research physics. At the same time, they are pushing the limits of technological solutions for various subsystems: to achieve the desired ultra-low electron beam emittance required in the next generation machines, the magnetic lattice has to adopt a compact design with reduced magnet apertures and other constraints like high heat load from synchrotron radiation, dynamic pressure inside vacuum chambers and chamber wall impedance are presenting unique challenges for the vacuum and engineering teams. At Elettra-Sincrotrone Trieste (Italy), the Elettra 2.0 project aims to develop a new-generation storage ring. Taking into consideration the above-mentioned constraints, we decided to adopt a new design of a vacuum chamber, while utilizing novel pumping solutions to overcome hugely reduced conductance compared to the current machine. Large sputter ion pumps (SIP) will be in the majority replaced by distributed non-evaporable getter (NEG) coatings and small NEG cartridges and SIP pumps. For the synchrotron radiation handling, due to the tight space constraints imposed by the compact lattice, the photon absorption will be managed jointly with discrete and distributed solutions: photon absorbers have been carefully studied for combining compact form and high power density loads, while key sections of the new storage ring will be water-cooled. Throughout the whole development phase, we were using Monte-Carlo simulation codes like SynRad and MolFlow+ as effective tools supporting the design of new vacuum chambers and photon absorbers. The current state of development for the Elettra 2.0 vacuum system, the challenges we faced and the solutions we adopted are presented here.
Ultra-fast generator for impact ionization triggering
Authors: del Barrio Montañés A. A. , Senaj V. , Kramer T. , Dutheil Y. , Sack M. 
Published: January 2024

Abstract
In recent years, it has been discovered that thyristors triggered in impact ionization mode find their dI/dt capability boosted by up to three orders of magnitude. This innovative triggering requires applying an important overvoltage on the anode-cathode of the thyristor with a slew rate > 1 kV/ns. Compact pulse generators based on commercial off the shelf components (COTS) would allow the spread of this technology into numerous applications, including fast kicker generators for particle accelerators.
Our approach for such a compact pulse generator begins with a HV SiC MOS with an ultra-fast super-boosting gate driver. Super boosting in the gate of a 1.7 kV rated SiC MOS allows to reduce its rise time by a factor of ≈ 30 (datasheet tr = 20 ns vs. measured tr < 680 ps), resulting in an output voltage slew rate > 1 kV/ns and an amplitude > 1 kV.
Next, additional boosting is obtained by a Marx generator with D2PAK thyristors, reaching an output voltage slew rate > 16 kV/ns. Finally, creating sufficient current necessary for the triggering of a big thyristor presents a new challenge. In this paper, we present an upgraded board design with a higher current output capacity.
Additively manufactured tantalum cathode for FEBIAD type ion sources: production, geometric measurements, and high temperature test
Authors: Girotto A , Ballan M , Rebesan P , Dima R , Monetti A , Bodini I , Paderno D , Villa V , Pepato A , Manzolaro M 
Published: January 2024

Abstract
The Laser Powder Bed Fusion (LPBF) is an Additive Manufacturing (AM) technology suitable to produce almost free-form metallic components. At Legnaro National Laboratories (LNL) of the Italian National Institute for Nuclear Physics (INFN), the LPBF process was recently used to produce parts of the Forced Electron Beam Induced Arc Discharge (FEBIAD) ion source for the SPES Isotope Separation On-Line (ISOL) facility. In this work are presented the feasibility assessment and production steps of tantalum cathodes produced via AM; in addition, the results concerning both the dimensional-geometrical measurements and the preliminary high-temperature test are reported.
Design and Test of C-band Linac Prototypes for Electron FLASH Radiotherapy
Authors: Giuliano L. , Bosco F. , Carillo M. , Ficcadenti L. , Magi M. , Mostacci A. , Palumbo l L. , Migliorati M. , Faillace L. , Alesini D. , Faillace L. , Gallo A. , Iovine P. , Spataro B. , Felici G. , Di Francesco M. 
Published: January 2024

Abstract
Flash Therapy is a revolution in cancer cure since it spares healthy tissue from the damage of ionization radiations without decreasing its effectiveness in tumor control. To allow the implementation of the FLASH therapy concept into actual clinical use and treat deep tumors, Very High Electron Energy (VHEE) should be achieved in a range of 50-150 MeV. In the framework of the VHEE project carried out at Sapienza University, in collaboration with INFN, we investigate the main issues in designing a compact C band (5.712 GHz) electron linacs for FLASH Radiotherapy. In this paper, we describe the design strategy, the electromagnetic properties, and the first prototypes of the RF structures to be tested at Sapienza University.
Comparison of measurements and simulation results of dose for the flash radiation therapy beamline at PITZ
Authors: Amirkhanyan Z. , Aftab N. , Adhikari G. , Boonpornprasert P. , Georgiev G. , Grebinyk A. , Gross M. , Hoffmann A. , Krasilnikov M. , Kuhl T. , Li X. K. , Oppelt A. , Philipp S. , Riemer F. , Richard C. , Vashchenko G. , Stephan F. , Khachatryan V. 
Published: January 2024

Abstract
The high-brightness electron beam at the Photo Injector Test facility at DESY in Zeuthen (PITZ) is now also used for FLASHlab@PITZ: an R.&D platform for studying radiation biology and the FLASH effect in radiation therapy. The available parameter space of the electron beam with a momentum of 22 MeV/c allows bunch charges from 1 pC up to 5 nC, bunch durations of 0.160 ps and bunch train lengths up to 1 ms. The number of bunches in the single train can currently be varied between 1 and 1000 bunches, with an upgrade to 4500 foreseen in 2023. Radiation biology studies require accurate dose predic-tion, therefore Monte Carlo simulations based on the FLUKA code were performed. According to estimations, dose delivery of 0.002 Gy (low charge case 1 pC) and 10 Gy (high charge case 5 nC) is possible, if the beam is confined to a circular area with a radius of 5 mm with a lead collimator. For the Monte Carlo simulations, the experimental setup was accurately modelled, including the exit window, lead collimator, etc. Dose measurements were used to compare simulations with experiments. Dose profiles were experimentally measured with Gafchromic films and then compared with Monte Carlo simulations. The first experiments at FLASHlab@PITZ in 2023 have demonstrated flexible dose options for studying the FLASH effect and radiation biology studies.
Barycentric decomposition for quantum instruments
Authors: Pellonpää Juha-Pekka , Haapasalo Erkka , Uola Roope 
Published: January 2024

Abstract
We present a barycentric decomposition for quantum instruments whose output space is finite-dimensional and input space is separable. As a special case, we obtain a barycentric decomposition for channels between such spaces and for normalized positive-operator-valued measures in separable Hilbert spaces. This extends the known results by Ali and Chiribella et al on decompositions of quantum measurements, and formalizes the fact that every instrument between finite-dimensional Hilbert spaces can be represented using only finite-outcome instruments.