MOPOMS —  Poster Session - Matsaman   (13-Jun-22   14:00—16:00)

Paper	Title	Page
MOPOMS001	Progress on Development of AXSIS: A Femtosecond THz-Driven MeV Accelerator and keV X-Ray Source	621
	N.H. Matlis, M. Fakhari, F.X. Kärtner, T. Kroh, M. Pergament, T. Rohwer, M. Vahdani, D. Zhang CFEL, Hamburg, Germany R. Bazrafshan, F.X. Kärtner, T. Rohwer Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany R. Bazrafshan, M. Vahdani University of Hamburg, Hamburg, Germany M. Fakhari, D. Zhang DESY, Hamburg, Germany F.X. Kärtner, T. Kroh The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany
	Funding: This work was supported by KA908-12/1 of the Deutsche Forschungsgemeinschaft and by the ERC under the European Union’s Seventh Framework Program (FP7/2007-2013) through Synergy Grant AXSIS (609920). We report on the design and progress in implementing a THz-driven relativistic electron accelerator and associated X-ray source, the AXSIS Facility at DESY. We have developed a full layout of the machine based on a THz gun followed by a multi-cycle dielectric loaded metal waveguide THz linear accelerator to generate 20 MeV level, 10 fs electron bunches. The required THz pulse energies are on the mJ-level for the gun and multi-10-mJ-level for the THz linac. Customized laser technologies have been developed allowing for the generation of these pulses up to 1 kHz repetition rate. The generated electron bunches are then focused into a counter propagating optical pulse ’optical undulator’ to generate X-rays in the 6-7 keV range. We will discuss the overall layout of the machine, status of its implementation and technical challenges in the different components as well as diagnostics of this new type of accelerator and X-ray source.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS001
About •	Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 21 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS003	Single-Sided Pumped Compact Terahertz Driven Booster Accelerator	625
SUSPMF026	use link to see paper's listing under its alternate paper code
	T. Kroh, R. Bazrafshan, F.X. Kärtner, N.H. Matlis Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany M. Fakhari, M. Pergament, T. Rohwer, M. Vahdani, D. Zhang CFEL, Hamburg, Germany F.X. Kärtner The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany K. Kawase JAEA, Kizugawa, Japan
	Funding: European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013) through the Synergy Grant ’Frontiers in Attosecond X-ray Science: Imaging and Spectroscopy’ (609920). Scaling the RF-accelerator concept to terahertz (THz) frequencies brings several compelling advantages, including compactness, intrinsic timing between the photoemission and driving field sources, and high field gradients associated with the short THz wavelength and high breakdown threshold. Recent demonstrations of such THz powered accelerators relied on two counter-propagating single-cycle THz pulses. However, to achieve high energy gains in the acceleration process high energy THz pulses are needed which in turn require complex optical setups. Here, we present on the development of a matchbox sized multi-layered accelerator designed to boost the 50 keV output of a DC electron gun to energies of ~400 keV that only requires a single THz pulse to be powered. An integrated tunable mirror inside the structure interferes the front of the driving THz pulse with its rear part such that the field in the interaction region is optimized for efficient acceleration. This reduces the complexity of the required optical setup. Such a compact booster accelerator is very promising as electron source in ultrafast electron diffraction experiments and as booster stage prior to THz based LINACs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS003
About •	Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 20 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS004	Optimizing Activation Recipe with Cs, Te, O for GaAs-Based Photocathodes	628
	J. Bae, M.B. Andorf, I.V. Bazarov, A. Galdi, J.M. Maxson Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA L. Cultrera BNL, Upton, New York, USA
	Funding: Department of Energy (DOE) DE-SC0021039. GaAs-based photocathodes are the most popular electron sources for producing highly spin-polarized electron beams in accelerator physics and condensed matter physics. Spin-polarized photoemission requires activation to achieve Negative Electron Affinity (NEA). Conventional NEA surfaces such as CS-O/NF3 are extremely vacuum sensitive, and this results in rapid QE degradation. In this work, we activated GaAs with various recipes using Cs, Te, and oxygen. We demonstrate NEA activation on GaAs surfaces. Among Cs-Te activated samples, the oxidized sample showed the highest QE and longest lifetime at 780 nm.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS004
About •	Received ※ 04 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS005	Start-to-End Simulations of a THz-Driven ICS Source	631
	M. Fakhari, Y.-K. Kan DESY, Hamburg, Germany F.X. Kärtner The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany F.X. Kärtner Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany N.H. Matlis, M. Vahdanipresenter CFEL, Hamburg, Germany M. Vahdanipresenter University of Hamburg, Hamburg, Germany
	We present start-to-end simulations for a fully THz-driven table-top X-ray source. A dielectric-loaded metallic cavity operating at its Higher Order Mode accelerates 1 PC photo emitted electron bunch up to 430 keV kinetic energy. The output beam of the gun is injected into a dielectric-loaded waveguide where phase velocity of the traveling wave is adjusted in such a way that electrons see an accelerating field all the way along the tube resulting to an 18.5-MeV output beam which is then transported to an inverse Compton scattering (ICS) stage. The injection phase of the electrons can be tuned to introduce a negative energy chirp to the electron bunch leading to a ballistic bunch compression after the linac. In addition, a set of permanent magnet quadrupoles is designed to focus the beam at the ICS interaction point where the electron beam scatters off a 250-mJ, 0.5ps, 1-µm laser beam and generates an X-ray beam with 2.6x107 photons per shot containing photon energies 2keV< Eph <8keV in a beam with 50 mrad half opening angle. The required terahertz waves to power the gun and linac are 550-ps pulses at 300 GHz containing 5 mJ and 23 mJ energies respectively with 1 kHz repetition rate.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS005
About •	Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 25 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS007	Optimized Dielectric Loaded Waveguide Terahertz LINACs	634
SUSPMF028	use link to see paper's listing under its alternate paper code
	M. Vahdani University of Hamburg, Hamburg, Germany M. Fakhari DESY, Hamburg, Germany F.X. Kärtner The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany F.X. Kärtner Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany M. Vahdani CFEL, Hamburg, Germany
	Dielectric loaded waveguides (DLW) powered by multicycle terahertz (THz) pulses have shown promising performance as compact linear accelerators due to higher breakdown fields at THz frequencies compared to conventional RF components. By changing the dielectric dimensions one can control phase and group velocities of the THz pulse inside the DLW. Since optimum waveguide dimensions are dependent on initial electron energy, THz pulse energy, and etc., it is worthwhile to determine optimum values for different conditions to maximize final kinetic energy. In this work, we present a combined analytical/numerical guide to determine the optimum DLW parameters for single on-axis electron acceleration. We also introduce normalized graphic representations to visualize optimum designs for different initial electron and THz pulse energies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS007
About •	Received ※ 09 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 21 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS008	Diagnosis of Transverse Emittance in Laser-Driven Ion Beam	637
SUSPMF029	use link to see paper's listing under its alternate paper code
	T. Miyatake, I. Takemoto, Y. Watanabe Kyushu University, Interdisciplinary Graduate School of Engineering Sciences, Kasuga-Shi, Japan T.-H. Dinh, M. Kando, S. Kojima, K. Kondo, K. Kondo, M. Nishikino, M. Nishiuchi, H. Sakaki National Institutes for Quantum Science and Technology, Kyoto, Japan
	Funding: This work was supported by JST-MIRAI R&D Program No. JPMJMI17A1. This work was supported by JSPS KAKENHI Grant Number JP21J22132. Ion beam produced in laser-driven ion acceleration by ultra-intense lasers has characteristics of high peak cur-rent and low emittance. These characteristics become an advantage to operate the request for the beam applica-tion. Therefore, we study how to control the parameters with the laser-plasma interaction. Here, we used 2D Particle-in-Cell code to simulate the laser-driven ion acceleration and investigated the results in terms of transverse emittance, beam current, and brightness. The laser spot size and target thickness were changed in the simulation. And, these qualitative results show that interaction target thickness is a major factor in controlling beam characteristics.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS008
About •	Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 18 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS010	Beam Dynamics and Drive Beam Losses Within a Planar Dielectric Wakefield Accelerator	641
SUSPMF030	use link to see paper's listing under its alternate paper code
	T.J. Overton, Y.M. Saveliev Cockcroft Institute, Warrington, Cheshire, United Kingdom T.H. Pacey, Y.M. Saveliev STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom G.X. Xia UMAN, Manchester, United Kingdom
	Funding: Science and Technology Funding Council (STFC) Student Grant Beam-driven dielectric wakefield accelerators (DWA) have the potential to provide accelerating gradients in the GV/m range. The transverse dynamics in such devices need to be understood to avoid instabilities over long transport distances and facilitate beam matching to specific applications (e.g. FELs). This presentation details simulation studies of the magnitude of beam-breakup instability (BBU) in planar dielectric lined waveguides (DLWs). These are for DWA drive beams, with high charge and momentum that can be produced at current facilities. Using a series of perpendicular DLW segments has been proposed to control instabilities over larger distances. Using self-developed software, the beam dynamics of a drive beam within a DLW are simulated and the magnitude of beam losses along a DLW of varying lengths calculated and beam quality preservation investigated. Methods to reduce transverse instabilities have been explored, and the impact of these on the length of a possible DWA acceleration stage are investigated. An acceleration stage with m-scale length, consisting of multiple alternating planar DLWs, is suggested and preservation of beam quality along this distance is shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS010
About •	Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 17 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS012	Simulation Studies of Drive Beam Instability in a Dielectric Wakefield Accelerator	645
	W.H. Tan, P. Piot Northern Illinois University, DeKalb, Illinois, USA A. Huebl, R. Jambunathan, R. Lehé, A. Myers, T. Rheaume, J.-L. Vay, W. Zhang LBNL, Berkeley, USA P. Piot ANL, Lemont, Illinois, USA
	Funding: This work is supported by the US DOE award DE-SC0018656 with NIU and DE-AC02-06CH11357 with ANL. This work used resources from NERSC, supported by DOE contract DE-AC02-05CH11231. This research used WarpX, which is supported by the US DOE Exascale Computing Project. Primary WarpX contributors are with LBNL, LLNL, CEA-LIDYL, SLAC, DESY, CERN, and Modern Electron. Beam-driven collinear wakefield acceleration using structure wakefield accelerators promises a high gradient acceleration within a smaller physical footprint. Sustainable extraction of energy from the drive beam relies on precise understanding of its long term dynamics and the possible onset or mitigation of the beam instability. The advance of computational power and tools makes it possible to model the full physics of beam-driven wakefield acceleration. Here we report on the long-term beam dynamics studies of a drive beam considering the example of a dielectric waveguide using high fidelity particle-in-cell simulations performed with WarpX.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS012
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS013	Toward Emittance Measurements at 11.7 GHz Short-Pulse High-Gradient RF Gun	649
	S.V. Kuzikov, C.-J. Jing, E.W. Knight Euclid TechLabs, Solon, Ohio, USA G. Chen, C.-J. Jing, P. Piot, E.E. Wisniewski ANL, Lemont, Illinois, USA C.-J. Jing Euclid Beamlabs, Bolingbrook, USA P. Piot Fermilab, Batavia, Illinois, USA P. Piot, W.H. Tanpresenter Northern Illinois University, DeKalb, Illinois, USA
	Funding: This project is supported with DoE SBIR Phase II Grant #DE-SC0018709. A short pulse high gradient RF gun has been recently tested at Argonne Wakefield Accelerator (AWA) facility. The carried-out test showed that the 1,5-cell gun was able to inject 3 MeV, up to 100 pC bunches at room tem-perature being fed by 9 ns up to 300 MW 11.7 GHz puls-es. The cathode field was as high as about 400 MV/m. So high field is aimed to mitigate repealing Coulomb forces substantially. In accordance with simulations the emit-tance could be as low as less than 0.2 mcm. To obtain so low emittance in the experiment, the gun is assumed to be equipped with a downstream linac to be fed from the same power extractor as the gun itself. Here we report design of the RF power distribution system splitting RF power among the gun and the linac, results of low-power tests, and emittance measurement plans for upcoming new experiment at AWA.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS013
About •	Received ※ 01 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 01 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS014	Commissioning of a High-Gradient X-Band RF Gun Powered by Short RF Pulses from a Wakefield Accelerator	652
SUSPMF040	use link to see paper's listing under its alternate paper code
	W.H. Tan, X. Lu, P. Piot Northern Illinois University, DeKalb, Illinois, USA S.P. Antipov, C.-J. Jing, E.W. Knight, S.V. Kuzikov Euclid TechLabs, Solon, Ohio, USA D.S. Doran, G. Ha, C.-J. Jing, W. Liu, X. Lu, P. Piot, P. Piot, J.G. Power, J. Shao, C. Whiteford, E.E. Wisniewski ANL, Lemont, Illinois, USA
	Funding: This work is supported by the U.S. DOE, under award No. DE-SC0018656 to NIU, DOE SBIR grant No DE-SC0018709 at Euclid Techlabs LLC, and contract No. DE-AC02-06CH11357 with ANL. A high-gradient X-band (11.7-GHz) photoinjector developed by Euclid Techlabs, was recently commissioned at the Argonne Wakefield Accelerator (AWA). The system comprises a 1+1/2-cell RF gun powered by short RF pulses generated as a train of high-charge bunches from the AWA accelerator passes through a slow-wave power extraction and transfer structure. The RF photoinjector was reliably operating with electric fields in excess of 300 MV/m on the photocathode surface free of breakdown and with an insignificant dark-current level. We report on the RF-gun setup, commissioning, and the associated beam generation via photoemission.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS014
About •	Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 19 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS015	Temporal and Spatial Characterization of Ultrafast Terahertz Near-Fields for Particle Acceleration	656
SUSPMF031	use link to see paper's listing under its alternate paper code
	A.E. Gabriel, M.C. Hoffmann, E.A. Nanni, M.A.K. Othman SLAC, Menlo Park, California, USA
	Funding: This work was supported by Department of Energy contract DE-AC02-76SF00515. We have measured the THz near-field in order to inform the design of improved THz-frequency accelerating structures. THz-frequency accelerating structures could provide the accelerating gradients needed for next generation particle accelerators with compact, GV/m-scale devices. One of the most promising THz generation techniques for accelerator applications is optical rectification in lithium niobate using the tilted pulse front method. However, accelerator applications are limited by significant losses during transport of THz radiation from the generating nonlinear crystal to the acceleration structure. In addition, the spectral properties of high-field THz sources make it difficult to couple THz radiation into accelerating structures. A better understanding of the THz near-field source properties is necessary for the optimization of THz transport and coupling. We have developed a technique for detailed measurement of the THz near-fields and used it to reconstruct the full temporal 3D THz near-field close to the LN emission face. Analysis of the results from this measurement will inform designs of novel structures for use in THz particle acceleration.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS015
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS016	Application of Nanostructures and Metamaterials in Accelerator Physics	659
	J. Resta-López ICMUV, Paterna, Spain Ö. Apsimon, C. Bonțoiu, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom A. Bonatto Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil B. Galante CERN, Meyrin, Switzerland C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom G.X. Xia UMAN, Manchester, United Kingdom
	Funding: This work is supported by the Generalitat Valenciana under Grant agreement No. CIDEGENT/2019/058. Carbon-based nanostructures and metamaterials offer extraordinary mechanical and opto-electrical properties, which make them suitable for applications in diverse fields, including, for example, bioscience, energy technology and quantum computing. In the latest years, important R&D efforts have been made to investigate the potential use of graphene and carbon-nanotube (CNT) based structures to manipulate and accelerate particle beams. In the same way, the special interaction of graphene and CNTs with charged particles and electromagnetic radiation might open interesting possibilities for the design of compact coherent radiation sources, and novel beam diagnostics techniques as well. This paper gives an overview of novel concepts based on nanostructures and metamaterials with potential application in the field of accelerator physics. Several examples are shown and future prospects discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS016
About •	Received ※ 08 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 13 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS017	Beam Transport Simulations Through Final Focus High Energy Transport Lines with Implemented Gabor Lenses	663
	A. Sherjan, M. Droba, O. Meusel, S. Reimann, K.I. Thoma IAP, Frankfurt am Main, Germany S. Reimann GSI, Darmstadt, Germany
	First investigations on Gabor Lens GL2000 at Goethe University have shown that it is possible to confine a 2m long stable Electron Plasma Column and to apply it as a hadron beam focusing device. With this knowledge theoretical implementations of GLs in final focus and transfer lines have started. The focusing with GLs is a weak but smooth focusing in radial direction. The GL is a suitable and inexpensive choice in addition to the existing focusing elements eg. magnetic quadrupoles. The device helps to improve beam quality and minimize losses over long distances. The investigation of relativistic hadron beams in GeV range using the example of the proposed NA61/SHINE VLE-beamline at CERN is carried out and will be presented. Thin-matrix simulations with a generated distribution as well as field map simulations with generated and realistic distributions (Geant4) at 1 - 6 GeV/c have been analysed and compared. In addition, the H4-beamline at North Area (CERN) is proposed to implement GLs for experimental tests.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS017
About •	Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 14 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS018	Tungsten Electron Emitter (TE²) with Direct Heated Cathode by Plasma Stream	667
	K.I. Thoma, M. Droba, T. Dönges, O. Meusel, H. Podlech, K. Schulte-Urlichs IAP, Frankfurt am Main, Germany K. Schulte-Urlichs, K.I. Thoma GSI, Darmstadt, Germany
	At Goethe-University, a novel concept of heating metallic cathodes is currently under investigation. In the scope of the ARIES collaboration WP16, an RF-modulated electron gun was developed and manufactured for application in electron lenses for space charge compensation. The goal of this project is to increase the intensity of primary beams, especially in low energy booster synchrotrons like the SIS18 and SIS100 at GSI/FAIR or the SPS at CERN. The gun was designed to produce electron currents of 10 A at extraction voltages of 30 kV. The tungsten electron emitter (TE²) and the grid electrode were designed and manufactured to be integrated in the extractor of the original volume type ion source. Significant effort was put into a robust and flexible design with highly reliable key components. The cathode is heated by a plasma stream generated in the plasma chamber of the source. Different heating options of the cathode are currently being studied. This contribution presents the working principles of the electron gun and first measurements results of cathode heating.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS018
About •	Received ※ 18 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 26 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS019	The New SPARC_LAB RF Photo-Injector	671
	D. Alesini, M.P. Anania, M. Bellaveglia, A. Biagioni, F. Cardelli, G. Costa, M. Del Franco, G. Di Pirro, L. Faillace, M. Ferrario, G. Franzini, A. Gallo, A. Giribono, L. Piersanti, L. Sabbatini, A. Stella, A. Vannozzi INFN/LNF, Frascati, Italy A. Battisti, E. Chiadroni, G. Di Raddo, A. Liedl, V.L. Lollo, L. Pellegrino, R. Pompili, S. Romeo, V. Shpakov, C. Vaccarezza, F. Villa LNF-INFN, Frascati, Italy M. Carillo, E. Chiadroni Sapienza University of Rome, Rome, Italy A. Cianchi, M. Galletti Università di Roma II Tor Vergata, Roma, Italy
	A new RF photo-injector has been designed, realized and successfully installed at the SPARC_LAB facility (INFN-LNF, Frascati, Rome). It is based on a 1.6 cell RF gun fabricated with the new brazing free technology recently developed at the National Laboratories of Frascati. The electromagnetic design has been optimized to have a full compensation of the dipole and quadrupole field components introduced by the coupling hole with an improvement of the effective pumping speed with two added pumping ports. The gun is overcoupled (\beta=2) to reduce the filling time and to allow the operation with short RF pulses. The overall injector integrates a new solenoid with a remote control of the transverse position and a variable skew quadrupole for the compensation of residual quadrupole field components. It also allows an on axis laser injection system with the last mirror in air, and the possibility of a future integration of an X/C band cavity linearizer. In the paper we report the main characteristics of the electromagnetic and mechanical design and the low and high power test results that shows the extremely good perfomances of the new device.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS019
About •	Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 26 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS020	Dark Current Studies for a High Gradient SW C-Band RF Gun	675
	F. Cardelli, D. Alesinipresenter, L. Faillace, A. Giribono, A. Vannozzi INFN/LNF, Frascati, Italy G. Di Raddo LNF-INFN, Frascati, Italy T.G. Lucas PSI, Villigen PSI, Switzerland
	It is now well-established that for the generation of very high brightness beams, required for fourth generation light sources, it is highly advantageous to use injectors based on Radiofrequency photo-guns with very high peak electric fields on the cathode (>120 MV/m). This very high surface electric field leads to the generation of undesirable electrons due to the field emission effect. The emitted electrons can be captured and propagate along the Linac forming a dark current beam, leading to background radiation that can damage the instrumentation and radioactivate components. Consequently, it is important that the emission of these electrons, and their subsequent transportation, is carefully evaluated. Recently, in the framework of the I-FAST project, a high gradient, standing wave, C-band (5712 MHz) RF photogun has been designed and will be realized soon. In this paper, the results of dark current studies and simulations are illustrated. The transport efficiency and the spectrum of the dark current have been evaluated by Particle-In-Cell simulations for different cathode peak field values considering also the effect of the focusing solenoid on the dark current beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS020
About •	Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 30 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS021	The New C Band Gun for the Next Generation RF Photo-Injectors	679
	D. Alesini, M. Ferrario, A. Giribono, A. Gizzi, L. Piersanti, A. Vannozzi INFN/LNF, Frascati, Italy F. Cardelli, G. Di Raddo, L. Faillace, S. Lauciani, A. Liedl, L. Pellegrino, C. Vaccarezza LNF-INFN, Frascati, Italy G. Castorina AVO-ADAM, Meyrin, Switzerland M. Croia ENEA Casaccia, Roma, Italy L. Ficcadenti INFN-Roma, Roma, Italy G. Pedrocchi SBAI, Roma, Italy
	Funding: European Union’s Horizon 2020 Research and Innovation programme under GA No 101004730 and INFN Commission V. RF photo-injectors are widely used in modern facilities, especially in FEL, as very low-emittance and high-brightness electron sources. Presently, the RF technology mostly used for RF guns is the S band (3 GHz) with typical cathode peak fields of 80-120 MV/m and repetition rates lower than 120 Hz. There are solid reasons to believe that the frequency step-up from S band to C band (6 GHz) can provide a strong improvement of the beam quality due to the potential higher achievable cathode field (>160 MV/m) and higher repetition rate (that can reach the kHz level). In the contest of the European I.FAST project, a new C band gun has been designed and will be realized and tested. It is a 2.5 cell standing wave cavity with a four port mode launcher, designed to operate with short RF pulses (<300 ns) and cathode peak field larger than 160 MV/m. In the paper we present the electromagnetic and thermo-mechanical design and the results of the prototyping activity and rf measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS021
About •	Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS022	Studies of a Ka-Band High Power Klystron Amplifier at INFN-LNF	683
	M. Behtouei, L. Faillace, A. Mostacci, B. Spataro LNF-INFN, Frascati, Italy F. Bosco, M. Carillopresenter, M. Migliorati, A. Mostacci, L. Palumbo Sapienza University of Rome, Rome, Italy F. Di Paolo, S. Fantauzzi, A. Leggieri, F. Marrese, L. Valletti Università degli Studi di Roma "Tor Vergata", Roma, Italy G. Torrisi INFN/LNS, Catania, Italy
	In the framework of the Compact Light XLS project, a Ka-band linearizer with electric field ranging from 100 to 150 MV/m is requested. In order to feed this structure, a proper Ka-band high power klystron amplifier with a high efficiency is needed. This paper reports a possible solution for a klystron amplifier operating on the TM010 mode at 36 GHz, the third harmonic of the 12 GHz linac frequency, with an efficiency of 44% and 10.6 MW radiofrequency output power. We discuss also here the high-power DC gun with the related magnetic focusing system, the RF beam dynamics and finally the multiphysics analysis of a high- power microwave window for a Ka-band klystron providing 16MW of peak power.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS022
About •	Received ※ 18 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 10 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS023	Start-to-End Beam-Dynamics Simulations of a Compact C-Band Electron Beam Source for High Spectral Brilliance Applications	687
	L. Faillace, M. Behtouei, B. Spataro, C. Vaccarezza LNF-INFN, Frascati, Italy R.B. Agustsson, I.I. Gadjev, S.V. Kutsaev, A.Y. Murokh RadiaBeam, Santa Monica, California, USA F. Bosco, M. Carillopresenter, L. Giuliano, M. Migliorati, A. Mostacci, L. Palumbo Sapienza University of Rome, Rome, Italy D.L. Bruhwiler RadiaSoft LLC, Boulder, Colorado, USA O. Camacho, A. Fukasawa, N. Majernik, J.B. Rosenzweig, O. Williams UCLA, Los Angeles, USA A. Giribono INFN/LNF, Frascati, Italy S.G. Tantawi SLAC, Menlo Park, California, USA
	Funding: This work is partially supported by DARPA under the Contract No. HR001120C0072, by DOE Contract DE-SC0009914, DOE Contract DE-SC0020409, and by the National Science Foundation Grant No. PHY-1549132. Proposals for new linear accelerator-based facilities are flourishing world-wide with the aim of high spectral brilliance radiation sources. Most of these accelerators are based on electron beams, with a variety of applications in industry, research and medicine such as colliders, free-electron lasers, wake-field accelerators, coherent THz and inverse Compton scattering X/’ sources as well as high-resolution diagnostics tools in biomedical science. In order to obtain high-quality electron beams in a small footprint, we present the optimization design of a C-band linear accelerator machine. Driven by a novel compact C-band hybrid photoinjector, it will yield ultra-short electron bunches of few 100’s pC directly from injection with ultra-low emittance, fraction of mm-mrad, and a few hundred fs length simultaneously, therefore satisfying full 6D emittance compensation. The normal-conducting linacs are based on a novel high-efficiency design with gradients up to 50 MV/m. The beam maximum energy can be easily adjusted in the mid-GeV’s range. In this paper, we discuss the start-to-end beam-dynamics simulations in details.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS023
About •	Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS025	Photocathode Performance Characterisation of Ultra-Thin MgO Films on Polycrystalline Copper	691
SUSPMF039	use link to see paper's listing under its alternate paper code
	C. Benjamin, H.M. Churn, L.B. Jones, T.C.Q. Noakes STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom G.R. Bell, C. Benjamin, T.J. Rehaag University of Warwick, Coventry, United Kingdom H.M. Churn, L.B. Jones, T.C.Q. Noakes Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Department of Physics, The University of Warwick, Coventry, United Kingdom STFC ASTeC, Daresbury, Warrington, United Kingdom WA4 4AD 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)***. *D.H. Dowell, et al, Nucl. Instr. and Meth A (2010), doi:10.1016/j.nima.2010.03.104 **V. Chang, et al, Phys. Rev. B (2018), doi.org/10.1103/PhysRevB.97.155436 ***Proc. FEL ’13, TUPPS033, 290-293
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS025
About •	Received ※ 19 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 21 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS027	Synthesis of First Caesium Telluride Photocathode at ASTeC Using Sequential and Co-Deposition Method	695
	R. Valizadeh, A.N. Hannah STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom V.R. Dhanak The University of Liverpool, Liverpool, United Kingdom S. Lederer DESY, Hamburg, Germany
	Caesium Telluride (Cs2Te) photocathodes, are the elec-tron source of choice, by many global accelerators such as European XFEL, FLASH and AWA. It offers high quantum efficiency and reasonable operational lifetime with lower vacuum requirements than multi-alkali photocathodes. In this paper, we report on the first synthesised CsxTe photocathodes at ASTeC, using both sequential and co-deposition of Te and Cs on Mo substrate. Te deposition is carried out using ion beam deposition whilst the Cs is deposited using a SAES getter alkali. The ion beam deposition of Te provides a high degree of control to give a dense, smooth layer with a reproducible film thickness. The chemical state with respect to film composition of the deposited CsxTe is determined with in-situ XPS anal-yses. The films exhibit a quantum efficiency between 7.5 to 9 % at 266 nm wavelength.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS027
About •	Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 06 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS028	Stability and Lifetime Studies of Carbon Nanotubes for Electron Cooling in ELENA	699
	B. Galante, G. Tranquille CERN, Meyrin, Switzerland J. Resta-López, C.P. Welschpresenter Cockcroft Institute, Warrington, Cheshire, United Kingdom J. Resta-López, C.P. Welschpresenter The University of Liverpool, Liverpool, United Kingdom J. Resta-López ICMUV, Paterna, Spain
	Funding: Work supported by EU Horizon 2020 research and innovation programme under the Marie Sk’odowska-Curie grant agreement No 721559. Electron cooling is a fundamental process to guarantee beam quality in low energy antimatter facilities. In ELENA, the electron cooler reduces the emittance blow-up of the antiproton beam so that a focused and bright beam can be delivered to the experiments at the unprecedentedly low energy of 100 keV. To achieve a cold beam at this low energy, the electron gun must emit a monoenergetic and relatively intense electron beam. An optimization of the electron gun involving a cold cathode is studied to investigate the feasibility of using carbon nanotubes (CNTs) as cold electron field emitters. CNTs are considered among the most promising field emitting materials. However, stability data for emission over hundreds of hours, as well as lifetime and conditioning process studies to ensure optimal performance, are still incomplete or missing, especially if the aim is to use them in operation. This contribution reports experiments that characterize these properties and assess whether CNTs are suitable to be used as cold electron field emitters for many hundreds of hours.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS028
About •	Received ※ 20 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 22 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS029	HPC Modeling of a High-Gradient C-Band Linac for Hard X-Ray Free-Electron Lasers	703
	T.B. Bolin, S. Biedron UNM-ECE, Albuquerque, USA S. Sosa ODU, Norfolk, Virginia, USA
	The production of soft to hard x-rays (up to 25 keV) at XFEL (x-ray free-electron laser) facilities has enabled new developments in a broad range of disciplines. Great potential exists for new scientific discovery at higher energies (42+ keV) such as envisioned at MaRIE (Matter-Radiation Interactions in Extremes) at Los Alamos National Laboratory. These instruments can require a large amount of real estate, which quickly escalates costs: The driver of the FEL is typically an electron beam linear accelerator (LINAC) and the need for higher beam energies capable of generating these X-rays can dictate that the linac becomes longer. State of art accelerating technology is required to reduce the linac length by reducing the size of the cavities, providing for compact, high-frequency, high acceleration gradients. Here, we describe using the Argonne Leadership Computing Facility (ALCF) to facilitate our investigations into design concepts for future XFEL high-gradient LINAC’s in the C-band (~4-8 GHz). We investigate two different traveling wave (TW) geometries optimized for high-gradient operation as modeled at the ALCF using VSim software.* * https://www.txcorp.com
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS029
About •	Received ※ 03 July 2022 — Accepted ※ 04 July 2022 — Issue date ※ 08 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS032	Compact-Two-Octave-Spanning Perpendicular Kicker of MeV Electrons Based on a Cubic Magnet Dipole Array	706
	T. Rohwer, R. Bazrafshan, F.X. Kärtner, N.H. Matlis Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany R. Bazrafshan University of Hamburg, Hamburg, Germany F.X. Kärtner The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany F.X. Kärtner CFEL, Hamburg, Germany P. Vagin DESY, Hamburg, Germany
	Funding: This work has been supported by the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013) through the Synergy Grant AXSIS (609920). New compact particle acceleration structures, including but not limited to plasma, THz and direct laser driven accelerators, have in common that they cover a wide energy range of potential final energies and often show a large energy spread. Moreover, they may initially have a rather large emittance. To analyze the energy range of a single shot and/or to deflect the beam to safely dump the electrons away from an end-station requires an electron kicker covering a large energy range. Here, we present a magnetic dipole structure based on a 2D Halbach array. For the current experimental test accelerator in AXSIS, an electron beam in the energy range from 4 to 20 MeV is deflected by 90 degree and energetically dispersed. In direct contrast to a simple magnetic dipole, an array of cubic magnet blocks with tailored magnetization directions allows a focusing of the beam for both longitudinal and transverse directions at 90 degree bend. A generic algorithm optimizes the magnetic field array to the predefined deflection angle and divergence. The modular array structure, in combination with the algorithm enables a simple exchange of magnets to adapt for different beam parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS032
About •	Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 14 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS033	Emittance Measurements of Nanoblade-Enhanced High Field Cathode	709
	G.E. Lawler, N. Majernik, J.I. Mann, N.E. Montanez, J.B. Rosenzweig UCLA, Los Angeles, California, USA V.S. Yu RadiaBeam, Santa Monica, California, USA
	Funding: This work was supported by the Center for Bright Beams, National Science Foundation Grant No. PHY-1549132. High brightness cathodes are increasingly a focus for accelerator applications ranging from free electron lasers to ultrafast electron diffraction. There is further an increasing interest in fabrication and control of cathode surface to better control the emission characteristics and improve beam brightness. One method which we can consider is based on well-known silicon nanofabrication techniques which we use to create patterned cathode surfaces. The sharp edges produced lead to field emission increases and high brightness emission. We have demonstrated that a beam can be successfully extracted with a low emittance and we have reconstructed a portion of the energy spectrum. Due to the simplicity of extended geometries in nanofabrication our beam uniquely possesses a high aspect ratio in its transverse cross section. We can begin to consider modifications for emittance exchange beamlines and having shown the patterning principle is sound we can consider additional patterns such as hollow beams. Future work will continue to characterize the produced beam and the addition of fabrication steps to remove one of the blades in the double blade geometry in order to more accurately characterize the emission.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS033
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 10 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS034	Material Normal Energy Distribution for Field Emission Analyses From Monocrystalline Surfaces	713
	J.I. Mann, Y. Li, J.B. Rosenzweig UCLA, Los Angeles, California, USA T. Arias, J.K. Nangoi Cornell University, Ithaca, New York, USA
	Funding: National Science Foundation Grant No. PHY-1549132 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS034
About •	Received ※ 20 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 06 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS036	Simulations of Laser Field Emission from Nanostructures with Image Charge Trapping and Band Structure Transitions	717
	B. Wang, G.E. Lawler, J.I. Mannpresenter, J.B. Rosenzweig UCLA, Los Angeles, California, USA T. Arias, J.K. Nangoi Cornell University, Ithaca, New York, USA S.S. Karkare Arizona State University, Tempe, USA
	Funding: National Science Foundation Grant No. PHY-1549132 Laser-induced field emission from nanostructures as a means to create high brightness electron beams has been a continually growing topic of study. Experiments using nanoblade emitters have achieved peak fields upwards of 40 GV/m, begging further investigation in this extreme regime. A recent paper has provided analytical reductions of the common semi-infinite Jellium system for pulsed incident lasers. We utilize these results as well as similar previous results to further understand the physics underlying electron rescattering-type emissions. We progress in numerically evaluating the analytical solution to attempt to more efficiently generate spectra for this system. Additionally, we use the full 1-D time-dependent Schrödinger equation with a Hartree potential and a dispersion-relation transition from material to vacuum to study the same system. We determine what importance the inclusion of the material band structure may have on emissions using this computationally challenging approach.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS036
About •	Received ※ 08 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 27 June 2022 — Issue date ※ 01 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS039	Study of Material Choice in Beam Dumps for Energetic Electron Beams	721
	D. Zhu, R.T. Dowd, Y.E. Tanpresenter AS - ANSTO, Clayton, Australia
	Lead is typically used as the initial target in a design for beam dumps for high energy electron beams (>20 MeV). Electron beams with energies above 20 MeV are usually built within concrete bunkers and therefore the design of any beam dump would just be a lead block (very cost effective) as close to the electron source as possible, after a vacuum flange of some sort. In a study of a hypothetical 100 MeV electron beam inside a concrete bunker with an extremely low dose rate constraint outside the bunker, the thickness of lead required would have been too restrictive for a compact design. In this study we investigate the potential benefits of designs that incorpo-rate low Z materials like graphite as the primary target material in vacuum followed by progressively higher Z materials up to lead. The results show the more diffuse elastic scattering from the primary target reduces the back scattered photons and reduces the overall neutron genera-tion. The effect was a more compact design for the beam dump to meet the same dose rate constraint.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS039
About •	Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 19 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS040	Radiation Shielding Design for the X-Band Laboratory for Radio-Frequency Test Facility - X-Lab - at the University of Melbourne	724
	M. Volpi, R.P. Rassool, S.L. Sheehy, G. Taylor, S.D. Williams The University of Melbourne, Melbourne, Victoria, Australia D. Banon-Caballero IFIC, Valencia, Spain M. Boronat, N. Catalán Lasheras CERN, Meyrin, Switzerland R.T. Dowd AS - ANSTO, Clayton, Australia S.L. Sheehy ANSTO, Kirrawee DC New South Wales, Australia
	Here we report radiation dose estimates calculated for the X-band Laboratory for Accelerators and Beams (X-LAB) under construction at the University of Melbourne (UoM). The lab will host a CERN X-band test stand containing two 12 GHz 6 MW klystron amplifiers. By power combination through hybrid couplers and the use of pulse compressors, up to 50 MW of peak power can be sent to any of to either of the two test slots at pulse repetition rates up to 400 Hz. The test stand is dedicated to RF conditioning and testing CLIC’s high gradient accelerating structures beyond 100 MV/m. This paper also gives a brief overview of the general principles of radiation protection legislation; explains radiological quantities and units, including some basic facts about radioactivity and the biological effects of radiation; and gives an overview of the classification of radiological areas at X-LAB, radiation fields at high-energy accelerators, and the radiation monitoring system used at X-LAB. The bunker design to achieve a dose rate less than annual dose limit of 1 mSv is also shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS040
About •	Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 15 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS041	Concrete Shielding Activation for Proton Therapy Systems Using BDSIM and FISPACT-II	728
SUSPMF096	use link to see paper's listing under its alternate paper code
	E. Ramoisiaux, E. Gnacadja, C. Hernalsteens, N. Pauly, R. Tesse, M. Vanwelde ULB, Bruxelles, Belgium C. Hernalsteens CERN, Meyrin, Switzerland F. Stichelbaut IBA, Louvain-la-Neuve, Belgium
	Proton therapy systems are used worldwide for patient treatment and fundamental research. The generation of secondary particles when the beam interacts with the beamline elements is a well-known issue. In particular, the energy degrader is the dominant source of secondary radiation. This poses new challenges for the concrete shielding of compact systems and beamline elements activation computation. We use a novel methodology to seamlessly simulate all the processes relevant to the activation evaluation. A realistic model of the system is developed using Beam Delivery Simulation (BDSIM), a Geant4-based particle tracking code that allows a single model to simulate primary and secondary particle tracking and all particle-matter interactions. The secondary particle fluxes extracted from the simulations are provided as input to FISPACT-II to compute the activation by solving the rate equations. This approach is applied to the Ion Beam Applications (IBA) Proteus®ONE (P1) system and the shielding of the proton therapy research centre of Charleroi, Belgium. Proton loss distributions are used to model the production of secondary neutrals inside the accelerator structure. Two models for the distribution of proton losses are compared for the computation of the clearance index at specific locations of the design. Results show that the variation in the accelerator loss models can be characterised as a systematic error.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS041
About •	Received ※ 19 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 22 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS042	Comparison Between Run 2 TID Measurements and FLUKA Simulations in the CERN LHC Tunnel of the Atlas Insertion Region	732
	D. Prelipcean, K. Biłko, F. Cerutti, A. Ciccotelli, D. Di Francesca, R. García Alía, B. Humannpresenter, G. Lerner, D. Ricci, M. Sabaté-Gilarte CERN, Meyrin, Switzerland B. Humannpresenter TU Vienna, Wien, Austria
	In this paper we present a systematic benchmark between the simulated and the measured data for the radiation monitors useful for Radiation to Electronics (R2E) studies at the Large Hadron Collider (LHC) at CERN. For this purpose, the radiation levels in the main LHC tunnel on the right side of the Interaction Point 1 (ATLAS detector) are simulated using the FLUKA Monte Carlo code and compared against Total Ionising Dose (TID) measurements performed with the Beam Loss Monitoring (BLM) system, and 180 m of Distributed Optical Fibre Radiation Sensor (DOFRS). Considering the complexity and the scale of the simulations as well as the variety of the LHC operational parameters, we find a generally good agreement between measured and simulated radiation levels, typically within a factor of 2 or better.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS042
About •	Received ※ 08 June 2022 — Revised ※ 23 June 2022 — Accepted ※ 26 June 2022 — Issue date ※ 09 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS043	Automated Analysis of the Prompt Radiation Levels in the CERN Accelerator Complex	736
	K. Biłko, R. García Alía, J.B. Potoinepresenter CERN, Meyrin, Switzerland
	The CERN injector complex is essential in providing high-energy beams to various experiments and to the world’s largest accelerator, the Large Hadron Collider (LHC). Beam losses linked to its operation result in a mixed radiation field which, through both cumulative and single-event effects poses a threat to the electronic equipment exposed in the tunnel. Therefore, detailed knowledge of the radiation distribution and evolution is necessary in order to implement adequate Radiation to Electronics mitigation and prevention measures, resulting in an improvement of the accelerator efficiency and availability. In this study, we present the automated analysis scheme put in place to efficiently process and visualise the radiation data produced by various radiation monitors, distributed at the four largest CERN accelerators, namely the Proton Synchrotron Booster, Proton Synchrotron, Super Proton Synchrotron, and the LHC, where a proton beam is accelerated gradually from 160 MeV up to 7 TeV.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS043
About •	Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 30 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS044	Implications and Mitigation of Radiation Effects on the CERN SPS Operation during 2021	740
	Y.Q. Aguiar, A. Apollonio, K. Biłko, M. Brucoli, M. Cecchetto, S. Danzeca, R. García Alía, T. Ladzinski, G. Lerner, J.B. Potoinepresenter, A. Zimmaro CERN, Meyrin, Switzerland
	During the Long Shutdown 2 (LS2, 2019-2020), the CERN accelerator complex has undergone major upgrades, mainly in preparation for the High-Luminosity (HL) LHC era, the ultimate capacity for its physics production. Therefore, several novel equipment and systems were designed and deployed throughout the accelerator complex. To comply with the radiation level specifications and avoid machine downtime due to radiation effects, the electronics systems exposed to radiation need to follow Radiation Hardness Assurance (RHA) methodologies developed and validated by the Radiation to Electronics (R2E) project at CERN. However, the establishment of such procedures is not yet fully implemented in the LHC injector chain, and some R2E failures were detected in the SPS during the 2021 operation. This work is devoted to describing and analysing the R2E failures and their impact on operation, in the context of the related radiation levels and equipment sensitivity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS044
About •	Received ※ 07 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 26 June 2022 — Issue date ※ 08 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS045	Vacuum Control System Upgrade for ALPI Accelerator	744
	G. Savarese, L. Antoniazzi, D. Bortolato, A. Conte, F. Gelainpresenter, D. Marcato, C.R. Roncolato INFN/LNL, Legnaro (PD), Italy
	The vacuum system of ALPI accelerator includes about 40 pumping groups based on turbomolecular pumps. The instrumentation of the accelerators complex is mainly the one installed in 90s, with consequent maintenance issues. The control and supervision systems were developed in the same period by an external company, which produced custom solutions for the HW and SW parts. Control devices are based on custom PLCs, while the supervision system is based on C and C#. The communication between the field and the supervisor is composed of multiple levels: RS-232 standard is used to transfer control parameter from the field devices up to custom multiplexers; RS-485 transmission is used from the multiplexers to two PC servers covering different sections of the installation; while Ethernet, is used to connect the servers and the operation console. Obsolescence and rigidity of the system, deficit of spare parts and impossibility of reparation or modification without external support, required a complete renovation of the vacuum system and relative controls in the next years. This paper describes the adopted strategy and the implementation status.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS045
About •	Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 30 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS046	Reliability Analysis of the HL-LHC Energy Extraction System	747
	M.R. Blaszkiewicz, A. Apollonio, T. Cartier-Michaud, B.I. Panev, M. Pojer, D. Wollmannpresenter CERN, Meyrin, Switzerland
	The energy extraction systems for the protection of the new HL-LHC superconducting magnet circuits are based on vacuum breakers. This technology allows to significantly reduce the switch opening time and increases the overall system reliability with reduced maintenance needs. This paper presents the results of detailed reliability studies performed on these new energy extraction systems. The study quantifies the risk of a failure which prevents correct protection of a magnet circuit and identifies the most critical components of the system. For this, the model considers factors such as block or component level failure probabilities, different maintenance strategies and repair procedures. The reliability simulations have been performed with AvailSim4, a novel Monte Carlo code for availability and reliability simulations. The results are compared with the system reliability requirements and provides insights into the most critical components.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS046
About •	Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 07 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS047	Control and Functional Safety Systems Design for Real-Time Conditioning of RF Structures at TEX	751
	S. Pioli, R. Gargana, D. Moriggipresenter LNF-INFN, Frascati, Italy F. Cardelli, P. Ciuffetti, C. Di Giulio INFN/LNF, Frascati, Italy
	We report the status of the development of an High Power RF Laboratory in X-Band called TEX (TEst-stand for X-Band). TEX is part of the LATINO (Laboratory in Advanced Technologies for INnOvation) initiative that is ongoing at the Frascati National Laboratories (LNF) of the Italian Institute for Nuclear Physics (INFN) that covers many different areas focused on particle accelerator technologies. TEX is a RF test facility based on solid-state K400 modulator from ScandiNova with a 50MW class X-band (11.994 GHz) klystron tube model VKX8311A operating at 50 Hz. This RF source will operate as resource for test and research programs such as the RF breakdown on RF waveguide components as well as high power testing of accelerating structures for future high gradient linear accelerator such as EuPRAXIA and CLIC. In this context we will present the whole EPICS control system design focusing on archiving, user interfaces and custom development made as part of the functional safety to deliver real-time RF breakdown detection integrated with the timing system of the facility.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS047
About •	Received ※ 16 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 27 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS048	Fast Trigger System for Beam Abort System in SuperKEKB	754
	H. Ikeda, T. Mimashi, S. Nakamura, T. Oki, S. Sasaki KEK, Ibaraki, Japan
	In order to protect the hardware components of the de-tector and accelerator from sudden beam loss of high beam currents, the fast beam abort system is developed in the SuperKEKB. The previous abort system was not fast enough for sudden beam loss that caused QCS quench, and it gave a damage to the collimator and the Belle-II detector. A fast abort system is required to pre-venting such damage. The abort system consists of sev-eral sensors that generate interlock signal (the loss moni-tor, dose in the Bell-II detector, and the magnet failure etc.), optical cable system to transfer the interlock signal to central control room (CCR), the abort trigger signal generation system and the abort kicker. To reduce total time, we reduce transmission time from local control room to CCR by changing signal cable route. Since the interlock signal produced by magnet power supply was slow, we modified the magnet power supply. For more quick generation of abort trigger signal, we increased number of the abort gap. By these improvements, an average abort time is reduced from 31µsec to 25µsec. This improvement looks small, but it brought preventing the serious radiation damage to many hardware compo-nents. Detail of the system and result is presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS048
About •	Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 10 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS050	Rigorous Approach for Calculation of Radiation of a Charged Particle Bunch Exiting an Open-Ended Dielectrically Loaded Waveguide	757
	S.N. Galyamin Saint Petersburg State University, Saint Petersburg, Russia S. Baturinpresenter ITMO University, Saint Petersburg, Russia
	Funding: Work supported by Russian Science Foundation (Grant No. 18-72-10137). Beam-driven radiation sources based on open-ended waveguide structures with dielectric filling are of essential interest due to their attractive possibilities to generate high-power narrow-band Cherenkov radiation*. An important problem here is to effectively extract the radiation from the waveguide to the open space. Therefore, further development of this scheme requires rigorous mathematical approach describing the interaction of both charged particle bunch and produced radiation with the open end of a waveguide. In this report, we present the corresponding analytical approach based on our recent paper** where diffraction of a waveguide mode at the open end of a dielectrically loaded waveguide has been rigorously investigated. * D. Wang et al., Rev. Sci. Instruments, Vol. 89, 093301 (2018). ** S.N. Galyamin et al., IEEE Trans. Microwave Theory Techn., Vol. 69, 2429-2438 (2021).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS050
About •	Received ※ 09 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 03 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)
MOPOMS052	6 MeV Novel Hybrid (Standing Wave - Traveling Wave) Photo-Cathode Electron Gun for a THz Superradiant FEL	760
	A. Nause, L. Feigin, A. Friedman, A. Weinberg Ariel University, Ariel, Israel A. Fukasawa, J.B. Rosenzweig UCLA, Los Angeles, California, USA B. Spataro LNF-INFN, Frascati, Italy
	A novel 6 MeV hybrid photo injector was designed and commissioned at Ariel University in Israel as an on-going collaboration with UCLA. This unique, new generation design provides a radically simpler approach to RF feeding of a gun/buncher system, leading to a much shorter beam via velocity bunching owed to an attached traveling wave section of the photo-injector. This design results in better performance in beam parameters, providing a high quality electron beam, with energy of 6 MeV, emittance of less than 3 ’m, and a 150 fs pulse duration at up to 1 nC per pulse. The Hybrid gun is driven by a SLAC XK5 Klystron as the high power RF source, and third harmonic of a fs level IR Laser amplifier (266 nm) to extract electrons from the Cathode. The unique e-gun will produce a bunched electron pulse to drive a THz FEL, which will operate at the super-radiance regime, and therefore requires extraordinary beam properties. It will also be used for MeV UED experiments in a separate line using a dogleg section. Here we describe the gun and presents experimental results from the gun and its sub-systems, including energy and charge measurements, compared with the design simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS052
About •	Received ※ 11 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 18 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)