bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulations of the suitability of a DC electron photogun and S-band accelerating structure as input to an X-band linac
Authors: Williams S D , Rassool R P , Sheehy S L , Taylor G N , Volpi M , Auchettl R , Dowd R T 
Published: January 2023

Abstract
Work has been underway for some time to design a compact electron beamline utilising X-band linear accelerating structures in the new Melbourne X-band Laboratory for Accelerators and Beams (X-LAB). The original design utilised an S-band RF photogun as an input to a pair of high gradient X-band linear accelerating structures, but we have been motivated to investigate an alternative starting section to allow for initial testing. This will utilise a DC photogun and S-band accelerating structure similar to those used at the Australian Synchrotron. Simulation results incorporating space charge of a beamline composed of a DC photogun, S-band accelerating structures, and two high gradient X-band structures will be presented. These simulation results will be optimised for minimum emittance at the end of the beamline.
Achievement of 200,000 hours of operation at KEK 7-GeV electron 4-GeV positron injector linac
Authors: Furukawa K , Akemoto M , Arakawa D , Arakida Y , Bando Y , Ego H , Enomoto Y , Higo T , Honma H , Iida N , Kakihara K , Kamitani T , Katagiri H , Kawamura M , Matsumoto S , Matsumoto T , Matsushita H , Mikawa K , Miura T , Miyahara F , Nakajima H , Natsui T , Ogawa Y , Ohsawa S , Okayasu Y , Oogoe T , Rehman M A , Satake I , Satoh M , Seimiya Y , Shidara T , Shirakawa A , Someya H , Suwada T , Tanaka M , Wang D , Yano Y , Yokoyama K , Yoshida M , Yoshimoto T , Zhang R , Zhou X 
Published: January 2023

Abstract
KEK electron positron injector LINAC initiated the injection operation into Photon Factory (PF) light source in 1982. Since then for 39 years, it has served for multiple projects, namely, TRISTAN, PF-AR, KEKB, and SuperKEKB. Its total operation time has accumulated 200 thousand hours on May 7, 2020. We are extremely proud of the achievement following continuous efforts by our seniors. The construction of the injector LINAC started in 1978, and it was commissioned for PF with 2.5 GeV electron in 1982. In parallel, the positron generator linac was constructed for the TRISTAN collider project. The slow positron facility was also commissioned in 1992. After the KEKB asymmetric-energy collider project was commissioned in 1998 with direct energy injections, the techniques such as two-bunch acceleration and simultaneous injection were developed. As the soft structure design of the LINAC was too weak against the great east Japan earthquake, it took three years to recover. Then the construction and commissioning for the SuperKEKB project went on, and the simultaneous top-up injection into four storage rings contributes to the both elementary particle physics and photon science.
Cooling challenges in a NEG-coated vacuum chamber of a light source
Authors: Motlagh S Talebi , Danaeifard A , Rahighi J , Saeidi F , Zamani F 
Published: January 2023

Abstract
In a Light Source, unused synchrotron radiation is being distributed along the walls of the chambers. Due to the small conductance of the chambers, vacuum pumping will be based on the distributed concept, and then non-evaporable getter (NEG) coating is extensively used. The vacuum chambers are made of copper alloys tube, and cooling circuits are welded to the chamber to remove the heat load from the radiation generated. Filler metal creates a brazed joint between the water-cooling pipe and the vacuum chamber body. The thermal conductivity of the fillers is less than the vacuum chamber body. On the other hand, the velocity of the water in the cooling pipe is a critical parameter in thermal calculations that must be taken into account. So, in this paper, we study and investigate the effects of the filler metal and the cooling water velocity on cooling the NEG-coated chambers.
Sensitivity of EEHG simulations to dynamic beam parameters
Authors: Samoilenko D , Hillert W , Pannek F , Ackermann S , Ferrari E , Mirian N , Niknejadi P , Paraskaki G , Schaper L , Curbis F , Pop M , Werin S 
Published: January 2023

Abstract
Currently, the Free electron laser user facility FLASH at DESY is undergoing a significant upgrade involving the complete transformation of one of its beamlines to allow external seeding. With the Echo-Enabled Harmonic Generation (EEHG) seeding method, we aim for the generation of fully coherent XUV and soft X-ray pulses at wavelengths down to 4 nm. The generated FEL radiation is sensitive to various electron beam properties, e.g., its energy profile imprinted either deliberately or by collective effects such as Coherent Synchrotron Radiation (CSR). In dedicated particle tracking simulations, one usually makes certain assumptions concerning the beam properties and the collective effects to simplify implementation and analysis. Here, we estimate the influence of some of the common assumptions made in EEHG simulations on the properties of the output FEL radiation, using the example of FLASH and its proposed seeding beamline. We conclude that the inherent properties of the FLASH1 beam, namely the negatively chirped energy profile, has dominant effect on the spectral intensity profile of the radiators output compare to that of the CSR induced chirp.
Emittance feedback for the Diamond-II storage ring using resonant excitation
Authors: Preston Shaun , Olsson Teresia , Singh Beni 
Published: January 2023

Abstract
In the Diamond Light Source storage ring, the vertical emittance is kept at 8 pm rad during operation to maintain the source brightness for the users. This is achieved by a feedback which modifies the skew quadrupole strengths, but has disadvantages such as the introduction of betatron coupling and vertical dispersion. For the proposed Diamond-II upgrade, the storage ring will have a much smaller horizontal emittance, meaning a significantly larger coupling would be required to reach the target vertical emittance, negatively affecting the off-axis injection process. To solve this problem, a feedback using the transverse multibunch feedback striplines to drive the beam at a synchrotron sideband is planned. By driving the beam resonantly in this way, the emittance can be increased without modification of the optics. This paper describes simulations of the effects of linear and non-linear optics on the excitation as well as the impact of the machine impedance for the Diamond-II storage ring.
Reconstruction and beam-transport study of the cERL dump line for high-power IR-FEL operation
Authors: Nakamura N , Tanimoto Y , Higashi N , Harada K , Shimada M , Uchiyama T , Nogami T , Ueda A , Nagahashi S , Obina T , Takai R , Sagehashi H , Nigorikawa K , Tanaka O , Kato R , Sakai H 
Published: January 2023

Abstract
Infrared (IR) SASE-FEL emission was successfully generated for macro pulses of about 1 μs with the maximum repetition rate of 5 Hz at the cERL. In the future, high-power FEL operation will be planned to increase electron bunches drastically with energy recovery. Therefore, the dump line was redesigned and reconstructed to increase the momentum acceptance and to improve the magnet system for avoiding serious beam loss in the high power FEL operation. Furthermore, the first beam-transport study was performed by transporting the beam directly from the injector to the beam dump through the reconstructed dump line. In this paper, we present the reconstructed dump line and the beam-transport study. The new dump line can be a model for dump lines of high-power ERL-FELs.
Photocathode performance characterisation of ultra-thin MgO films on polycrystalline copper
Authors: Benjamin C , Churn H M , Rehaag T J , Jones L B , Bell G R , Noakes T C Q 
Published: January 2023

Abstract
The performance expected from the next generation of electron accelerators is driving research into photocathode technology as this fundamentally limits the achievable beam quality. The performance characteristics of a photocathode are most notably: normalised emittance, brightness and energy spread. Ultra–thin oxide films on metal substrates have been shown to lower the work function (WF) of the surface, enhancing commonly utilised metal photocathodes, potentially improving lifetime and performance characteristics.
We present the characterisation of two MgO/Cu photocathodes grown at Daresbury. The surface properties such as: surface roughness, elemental composition and WF, have been studied using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). The photoemissive properties have been characterised with quantum efficiency (QE) measurements at 266 nm. Additionally, we measure the Transverse Energy Distribution Curves (TEDC) for these photocathodes under illumination at various wavelengths using ASTeC’s Transverse Energy Spread Spectrometer (TESS) and extract the Mean Transverse Energy (MTE).
Material normal energy distribution for field emission analyses from monocrystalline surfaces
Authors: Mann J I , Li Y , Nangoi J K , Arias T , Rosenzweig J B 
Published: January 2023

Abstract
Electron field emission is a complicated phenomenon which is sensitive not only to the particular material under illumination but also to the specific crystalline orientation of the surface. Summarizing the ability for a crystal to emit in a particular direction would be of great use when searching for good field emitters. In this paper we propose a material normal energy distribution which describes the ability of the bound electrons to tunnel under an intense electric field. This framework breaks a computationally expensive 3-D system down to a source distribution representation applicable for more efficient 1-D models. We use the Fowler-Nordheim framework to study the yield and MTE (mean transverse energy) from sources including gold, copper, and tungsten in both monocrystalline and polycrystalline forms. We find an increase in effective work function for field emission in the (111) direction for gold and copper associated with the Bragg plane intersections of the Fermi surface.
Towards high-repetition rate petawatt laser experiments with cryogenic jets using a mechanical chopper system
Authors: Rehwald M , Assenbaum S , Bernert C , Curry C B , Gauthier M , Glenzer S H , Göde S , Schoenwaelder C , Schramm U , Treffert F , Zeil K 
Published: January 2023

Abstract
Laser-plasma based ion accelerators require suitable high-repetition rate target systems that enable systematic studies at controlled plasma conditions and application-relevant particle flux. Self-refreshing, micrometer-sized cryogenic jets have proven to be an ideal target platform. Yet, operation of such systems in the harsh environmental conditions of high power laser induced plasma experiments have turned out to be challenging. Here we report on recent experiments deploying a cryogenic hydrogen jet as a source of pure proton beams generated with the PW-class ultrashort pulse laser DRACO. Damage to the jet target system during application of full energy laser shots was prevented by implementation of a mechanical chopper system interrupting the direct line of sight between the laser plasma interaction zone and the jet source.
Proposal for a compact neutron generator based on a negative deuterium ion beam
Authors: Jimbo Kouichi , Shirai Toshiyuki , Leung Ka-Ngo , Bibber Karl van 
Published: January 2023

Abstract
Interest in high intensity generators of neutrons for basic and applied science has been growing, and thus the demand for an economical neutron generator has been growing. A major driver for the development of high intensity neutron generators are studies of neutron disturbance in integrated circuits, for which a compact generator that can be easily accommodated in an ordinary size lab would be highly desirable. We have investigated possible designs for neutron generators based on the D-D fusion reaction, which produce direction dependent mono-energetic neutrons with carry-off energy larger than 2.45 MeV. Specifically, we find a negative deuterium ion beam most attractive for this application, and plan to construct such a system with a negative deuterium ion beam of 200 keV energy and 100 mA current as a prototype of this concept.
Study of transverse resonance island buckets at CESR
Authors: Wang S T , Khachatryan V 
Published: January 2023

Abstract
A 6-GeV lattice with the horizontal tune near a 3rd-order resonance line at 3νx
=2 is designed for studying the transverse resonance island buckets (TRIBs) at the Cornell Electron Storage Ring (CESR). The distribution of 76 sextupoles powered individually is optimized to maximize the dynamic aperture and achieve the desired amplitude-dependent tune shift αxx
and the resonant driving term h
30000, which are necessary conditions to form stable island buckets. The particle tracking simulations are developed to check and confirm the formation of TRIBs at different tunes with clearing kicks in this TRIBs lattice. Finally, the lattice is loaded in CESR and the TRIBs are successfully observed when the horizontal fractional tune is adjusted to 0.665, close to the 3rd-order resonance line. Bunch-by-bunch feedback is also explored to clear the particles in the main bucket and the island buckets, respectively.
Fast orbit response matrix measurement via sine-wave excitation of correctors at Sirius
Authors: Velloso M M S , de Sá F H , Alves M B 
Published: January 2023

Abstract
Sirius is the new 4th generation storage ring based synchrotron light source built and operated by the Brazilian Synchrotron Light Laboratory (LNLS). In this work, we report on the implementation at Sirius of a fast method for orbit response matrix (ORM) measurement which is based on sine-wave parallel excitation of orbit corrector magnets’ strength. This “AC method” has reduced the ORM measurement time from ∼ 25 minutes to 2.5–3 minutes and displayed increased precision if compared to the standard serial measurement procedure. When used as input to the Linear Optics from Closed Orbits (LOCO) correction algorithm, the AC ORM yielded similar optics corrections with less aggressive quadrupoles strength changes.
Beamline design and optimisation for high intensity muon beams at PSI
Authors: Valetov Eremey 
Published: January 2023

Abstract
The High Intensity Muon Beams (HIMB) project at the Paul Scherrer Institute (PSI) will provide muon intensities of the order of 1010 muons/s for particle physics and material science experiments, two orders of magnitude higher than the state of the art, which is currently available also at PSI. In particle transport simulations for the HIMB, we use G4beamline with measured + cross-sections and with variance reduction. We also use the codes COSY INFINITY, TRANSPORT, and TURTLE for some studies. We perform asynchronous Bayesian optimisation of the beamlines on a computing cluster using G4beamline and the optimisation package DeepHyper. We performed numerous studies for the design of the HIMB, and we produced various results, including the muon transmission, beam phase space, polarisation, and momentum spectrum.
Measurements of radiation fields from a ceramic break
Authors: Shobuda Yoshihiro , Toyama Takeshi , Yoshimoto Masahiro , Hatakeyama Shuichiro 
Published: January 2023

Abstract
Ceramic breaks are used in synchrotrons for many purposes. For example, they are inserted between the Multi-Wire Profile Monitor (MWPM) on the injection line at the Rapid Cycling Synchrotron (RCS) in J-PARC to completely prevent the wall currents accompanying beams from affecting the MWPM. On the other hand, from the viewpoint of suppressing beam impedances and the radiation fields from the ceramic breaks, it would be preferable that the inner surface of the ceramic break is coated with Titanium Nitride (TiN), or covered over capacitors. In this report, we measure the radiation fields from the ceramic break with and without capacitors as well as the beam profile and investigate the effect of the ceramic breaks on the measurements.
Strong-strong simulations of coherent beam-beam effects in the EIC
Authors: Qiang J , Hao Y , Luo Y , Montag C , Xu D , Willeke F 
Published: January 2023

Abstract
The high luminosity electron ion collider (EIC) will provide great opportunities in nuclear physics study and is under active design. The coherent effects due to the beam-beam interaction of two colliding beams can cause beam size blow-up and degrade the luminosity in the EIC. In this paper, we report on the study of coherent beam-beam effects in the EIC design using self-consistent strong-strong simulations. These simulations show the coherent dipole and quadrupole mode instabilities in the tune working point scan and bunch intensity scan.
The report of machine studies related to the vertical beam size blow-up in SuperKEKB LER
Authors: Terui S , Ishibashi T , Ohmi K , Funakoshi Y , Fukuma H , Ueki R , Ohnishi Y , Tobiyama M , Nakamura T 
Published: January 2023

Abstract
In the low energy ring (LER) for positrons in the SuperKEKB, a vertical beam size blow-up was observed when the bunch current was approximately 1 mA. If a beam size blow-up occurs, the design luminosity cannot be achieved. Therefore, beam size blow-ups must be pre-vented. According to calculations, the bunch current threshold of the transverse mode coupling instability (TMCI) is 2 mA or more, and the observed value is 50% or smaller. Ordinary TMCI cannot explain this vertical beam size blow-up. This paper shows that the cause of the vertical beam size blow-up can be determined by analyzing factors such as beam oscillation. The study results showed that the vertical beam size blow-up in the LER was caused by a -1 mode instability.
A beam position monitor for electron bunch detection in the presence of a more intense proton bunch for the AWAKE Experiment
Authors: Pakuza Collette , Burrows Philip , Corsini Roberto , Farabolini Wilfrid , Korysko Pierre , Krupa Michal , Lefevre Thibaut , Mazzoni Stefano , Senes Eugenio , Wendt Manfred 
Published: January 2023

Abstract
The Advanced Proton Driven Plasma Wakefield Experiment (AWAKE) at CERN uses 6 cm long proton bunches extracted from the Super Proton Synchrotron (SPS) at 400 GeV beam energy to drive high gradient plasma wakefields for the acceleration of electron bunches to 2 GeV within a 10 m length. Knowledge and control of the position of both copropagating beams is crucial for the operation of the experiment. Whilst the current electron beam position monitoring system at AWAKE can be used in the absence of the proton beam, the proton bunch signal dominates when both particle bunches are present simultaneously. A new technique based on the generation of Cherenkov diffraction radiation (ChDR) in a dielectric material placed in close proximity to the particle beam has been designed to exploit the large bunch length difference of the particle beams at AWAKE, 200 ps for protons versus a few ps for electrons, such that the electron signal dominates. Hence, this technique would allow for the position measurement of a short electron bunch in the presence of a more intense but longer proton bunch. The design considerations, numerical analysis and plans for tests at the CERN Linear Electron Accelerator for Research (CLEAR) facility are presented.
Dispersion-free steering beam based alignment at SwissFEL
Authors: Ferrari Eugenio , Calvi Marco , Ganter Romain , Kittel Christoph , Prat Eduard , Reiche Sven , Schietinger Thomas 
Published: January 2023

Abstract
Micron-level alignment of the undulator line is required for successful operation of linear accelerator based high gain free electron lasers to produce powerful radiation at X-rays’ wavelengths. Such precision in the straightness of the trajectory allows for an optimal transverse superposition between the electrons and the photon beam. This is extremely challenging and can only be achieved via beam-based techniques. In this paper we will report on the dispersion-free steering approach implemented at SwissFEL, that helped achieving improved performance for both the hard and soft X-ray beamlines.
Commissioning and first results of an x-band LLRF system for TEX test facility at LNF-INFN
Authors: Piersanti L , Alesini D , Bellaveglia M , Bini S , Buonomo B , Cardelli F , Di Giulio C , Di Pasquale E , Diomede M , Faillace L , Falone A , Franzini G , Gallo A , Giannetti G , Liedl A , Moriggi D , Pioli S , Quaglia S , Sabbatini L , Scampati M , Scarselletta G , Stella A , Tocci S , Zelinotti L 
Published: January 2023

Abstract
In the framework of LATINO project (Laboratory in Advanced Technologies for INnOvation) funded by Lazio regional government, the commissioning of the TEst stand for X-band (TEX) facility has started in 2021 at Frascati National Laboratories of INFN. Born as a collaboration with CERN to test high gradient accelerating structures, during 2022 TEX aims at feeding the first EuPRAXIA@SPARC_LAB X-band structure prototype. During 2021 the commissioning has been successfully carried out up to 48 MW. The power unit is driven by an X-band low level RF system, that employs a commercial S-band (2.856 GHz) Libera digital LLRF (manufactured by Instrumentation Technologies), with an up/down conversion stage and a reference generation and distribution system able to produce coherent frequencies for the American S-band and European X-band (11.994 GHz), both designed and realized at LNF. The performance of the system, with a particular focus on amplitude and phase resolution, together with klystron and driver amplifier jitter measurements, will be reviewed in this paper. Moreover, considerations on its suitability and main limitations in view of EuPRAXIA@SPARC_LAB project will be discussed.
Reconstruction of transverse phase space from transverse feedback data for real time extraction of vital LHC machine parameters
Authors: Kotzian G , Söderén M , Solvang P S , Valuch D , Stopjakova V 
Published: January 2023

Abstract
The LHC transverse feedback system (ADT) provides bunch by bunch, turn by turn, normalized and digitized beam position signals from four pick-ups per plane and for each beam. Together with already existing powerful computer-based observation systems, this data can be used to reconstruct in real-time the transverse phase space coordinates of the centre-of-charges, for each individual bunch. Such information is extremely valuable for machine operation, or transverse instability diagnostics.
This paper aims on discussing and evaluating methods of combining four position signals for such analysis in the presence of noise and with active transverse feedback. Comparisons are made based on the extraction of vital parameters like the fractional tune or transverse activity. Analytical and numerical results are further benchmarked against real beam data.