arXiv - PHYS - Accelerator Physics最新文献

{"title":"Quantitative description and correction of longitudinal drifts in the Fermilab linac","authors":"R. SharankovaFermi National Accelerator Laboratory, A. ShemyakinFermi National Accelerator Laboratory, S. RegoFermi National Accelerator LaboratoryEcole Polytechnique Palaiseau, France","doi":"arxiv-2407.17456","DOIUrl":"https://doi.org/arxiv-2407.17456","url":null,"abstract":"The Fermi National Accelerator Laboratory (Fermilab) Linac accepts 750 keV H-\u0000ions from the front end and accelerates them to 400 MeV for injection into the\u0000Booster rapid cycling synchrotron. Day-to-day drifts in the beam longitudinal\u0000trajectory during regular operation are of the order of several degrees. They\u0000are believed to cause additional losses in both the Linac and the Booster and\u0000are addressed by empirically adjusting cavity phases of front end and Linac RF\u0000cavities. This work explores a scheme for expressing these drifts in terms of\u0000phase shifts in the low-energy part of the Linac. Such a description allows for\u0000a simplified visual representation of the drifts, suggests a clear algorithm\u0000for their compensation, and provides a tool for estimating efficiency of such\u0000compensation.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"63 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141771407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Beam Stacking Experiment at a Fixed Field Alternating Gradient Accelerator","authors":"T. UesugiInstitute for Integrated Radiation and Nuclear Science, Kyoto University, Y. IshiInstitute for Integrated Radiation and Nuclear Science, Kyoto University, Y. KuriyamaInstitute for Integrated Radiation and Nuclear Science, Kyoto University, Y. MoriInstitute for Integrated Radiation and Nuclear Science, Kyoto University, C. JollySTFC ISIS Department, D. J. KelliherSTFC ISIS Department, J. -B. LagrangeSTFC ISIS Department, A. P. LetchfordSTFC ISIS Department, S. MachidaSTFC ISIS Department, D. W. Poshuma de BoerSTFC ISIS Department, C. T. RogersSTFC ISIS Department, E. YamakawaSTFC ISIS Department, M. Topp-MugglestoneJohn Adams Institute, University of Oxford","doi":"arxiv-2407.13962","DOIUrl":"https://doi.org/arxiv-2407.13962","url":null,"abstract":"A key challenge in particle accelerators is to achieve high peak intensity.\u0000Space charge is particularly strong at lower energy such as during injection\u0000and typically limits achievable peak intensity. The beam stacking technique can\u0000overcome this limitation by accumulating a beam at high energy where space\u0000charge is weaker. In beam stacking, a bunch of particles is injected and\u0000accelerated to high energy. This bunch continues to circulate, while a second\u0000and subsequent bunches are accelerated to merge into the first. It also allows\u0000the user cycle and acceleration cycles to be separated which is often valuable.\u0000Beam stacking is not possible in a time varying magnetic field, but a fixed\u0000field machine such as an Fixed Field Alternating Gradient Accelerator (FFA)\u0000does not sweep the magnetic field. In this paper, we describe experimental\u0000demonstration of beam stacking of two beams at KURNS FFA in Kyoto University.\u0000The momentum spread and intensity of the beam was analysed by study of the\u0000Schottky signal, demonstrating stacking with only a slight increase of momentum\u0000spread of the combined beams. The intensity of the first beam was, however,\u0000significantly reduced. RF knock-out is the suspected source of the beam loss.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"64 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interim report for the International Muon Collider Collaboration (IMCC)","authors":"C. Accettura, S. Adrian, R. Agarwal, C. Ahdida, C. Aimé, A. Aksoy, G. L. Alberghi, S. Alden, N. Amapane, D. Amorim, P. Andreetto, F. Anulli, R. Appleby, A. Apresyan, P. Asadi, M. Attia Mahmoud, B. Auchmann, J. Back, A. Badea, K. J. Bae, E. J. Bahng, L. Balconi, F. Balli, L. Bandiera, C. Barbagallo, R. Barlow, C. Bartoli, N. Bartosik, E. Barzi, F. Batsch, M. Bauce, M. Begel, J. S. Berg, A. Bersani, A. Bertarelli, F. Bertinelli, A. Bertolin, P. Bhat, C. Bianchi, M. Bianco, W. Bishop, K. Black, F. Boattini, A. Bogacz, M. Bonesini, B. Bordini, P. Borges de Sousa, S. Bottaro, L. Bottura, S. Boyd, M. Breschi, F. Broggi, M. Brunoldi, X. Buffat, L. Buonincontri, P. N. Burrows, G. C. Burt, D. Buttazzo, B. Caiffi, S. Calatroni, M. Calviani, S. Calzaferri, D. Calzolari, C. Cantone, R. Capdevilla, C. Carli, C. Carrelli, F. Casaburo, M. Casarsa, L. Castelli, M. G. Catanesi, L. Cavallucci, G. Cavoto, F. G. Celiberto, L. Celona, A. Cemmi, S. Ceravolo, A. Cerri, F. Cerutti, G. Cesarini, C. Cesarotti, A. Chancé, N. Charitonidis, M. Chiesa, P. Chiggiato, V. L. Ciccarella, P. Cioli Puviani, A. Colaleo, F. Colao, F. Collamati, M. Costa, N. Craig, D. Curtin, L. D'Angelo, G. Da Molin, H. Damerau, S. Dasu, J. de Blas, S. De Curtis, H. De Gersem, T. Del Moro, J. -P. Delahaye, D. Denisov, H. Denizli, R. Dermisek, P. Desiré Valdor, C. Desponds, L. Di Luzio, E. Di Meco, K. F. Di Petrillo, I. Di Sarcina, E. Diociaiuti, T. Dorigo, K. Dreimanis, T. du Pree, T. Edgecock, S. Fabbri, M. Fabbrichesi, S. Farinon, G. Ferrand, J. A. Ferreira Somoza, M. Fieg, F. Filthaut, P. Fox, R. Franceschini, R. Franqueira Ximenes, M. Gallinaro, M. Garcia-Sciveres, L. Garcia-Tabares, R. Gargiulo, C. Garion, M. V. Garzelli, M. Gast, C. E. Gerber, L. Giambastiani, A. Gianelle, E. Gianfelice-Wendt, S. Gibson, S. Gilardoni, D. A. Giove, V. Giovinco, C. Giraldin, A. Glioti, A. Gorzawski, M. Greco, C. Grojean, A. Grudiev, E. Gschwendtner, E. Gueli, N. Guilhaudin, C. Han, T. Han, J. M. Hauptman, M. Herndon, A. D. Hillier, M. Hillman, T. R. Holmes, S. Homiller, S. Jana, S. Jindariani, S. Johannesson, B. Johnson, O. R. Jones, P. -B. Jurj, Y. Kahn, R. Kamath, A. Kario, I. Karpov, D. Kelliher, W. Kilian, R. Kitano, F. Kling, A. Kolehmainen, K. C. Kong, J. Kosse, G. Krintiras, K. Krizka, N. Kumar, E. Kvikne, R. Kyle, E. Laface, K. Lane, A. Latina, A. Lechner, J. Lee, L. Lee, S. W. Lee, T. Lefevre, E. Leonardi, G. Lerner, P. Li, Q. Li, T. Li, W. Li, R. Li Voti, M. Lindroos, R. Lipton, D. Liu, M. Liu, Z. Liu, A. Lombardi, S. Lomte, K. Long, L. Longo, J. Lorenzo, R. Losito, I. Low, X. Lu, D. Lucchesi, T. Luo, A. Lupato, E. Métral, K. Mękała, Y. Ma, J. M. Mańczak, S. Machida, T. Madlener, L. Magaletti, M. Maggi, H. Mainaud Durand, F. Maltoni, M. Mandurrino, C. Marchand, F. Mariani, S. Marin, S. Mariotto, S. Martin-Haugh, M. R. Masullo, G. S. Mauro, A. Mazzolari, B. Mele, F. Meloni, X. Meng, M. Mentink, R. Miceli, N. Milas, A. Mohammadi, D. Moll, A. Montella, M. Morandin, M. Morrone, T. Mulder, R. Musenich, M. Nardecchia, F. Nardi, D. Neuffer, D. Newbold, D. Novelli, M. Olvegård, Y. Onel, D. Orestano, J. Osborne, S. Otten, Y. M. Oviedo Torres, D. Paesani, S. Pagan Griso, D. Pagani, K. Pal, M. Palmer, A. Pampaloni, P. Panci, P. Pani, Y. Papaphilippou, R. Paparella, P. Paradisi, A. Passeri, N. Pastrone, A. Pellecchia, F. Piccinini, H. Piekarz, T. Pieloni, J. Plouin, A. Portone, K. Potamianos, J. Potdevin, S. Prestemon, T. Puig, J. Qiang, L. Quettier, T. R. Rabemananjara, E. Radicioni, R. Radogna, I. C. Rago, A. Ratkus, E. Resseguie, J. Reuter, P. L. Ribani, C. Riccardi, S. Ricciardi, T. Robens, Y. Robert, C. Roger, J. Rojo, M. Romagnoni, K. Ronald, B. Rosser, C. Rossi, L. Rossi, L. Rozanov, M. Ruhdorfer, R. Ruiz, F. S. Queiroz, S. Saini, F. Sala, C. Salierno, T. Salmi, P. Salvini, E. Salvioni, N. Sammut, C. Santini, A. Saputi, I. Sarra, G. Scarantino, H. Schneider-Muntau, D. Schulte, J. Scifo, T. Sen, C. Senatore, A. Senol, D. Sertore, L. Sestini, R. C. Silva Rêgo, F. M. Simone, K. Skoufaris, G. Sorbello, M. Sorbi, S. Sorti, L. Soubirou, D. Spataro, A. Stamerra, S. Stapnes, G. Stark, M. Statera, B. M. Stechauner, S. Su, W. Su, X. Sun, A. Sytov, J. Tang, J. Tang, R. Taylor, H. Ten Kate, P. Testoni, L. S. Thiele, R. Tomas Garcia, M. Topp- Mugglestone, T. Torims, R. Torre, L. T. Tortora, S. Trifinopoulos, S. -A. Udongwo, I. Vai, R. U. Valente, U. van Rienen, R. van Weelderen, M. Vanwelde, G. Velev, R. Venditti, A. Vendrasco, A. Verna, A. Verweij, P. Verwilligen, Y. Villamzar, L. Vittorio, P. Vitulo, I. Vojskovic, D. Wang, L. -T. Wang, X. Wang, M. Wendt, M. Widorski, M. Wozniak, Y. Wu, A. Wulzer, K. Xie, Y. Yang, Y. C. Yap, K. Yonehara, H. D. Yoo, Z. You, M. Zanetti, A. Zaza, L. Zhang, R. Zhu, A. Zlobin, D. Zuliani, J. F. Zurita","doi":"arxiv-2407.12450","DOIUrl":"https://doi.org/arxiv-2407.12450","url":null,"abstract":"The International Muon Collider Collaboration (IMCC) [1] was established in\u00002020 following the recommendations of the European Strategy for Particle\u0000Physics (ESPP) and the implementation of the European Strategy for Particle\u0000Physics-Accelerator R&D Roadmap by the Laboratory Directors Group [2],\u0000hereinafter referred to as the the European LDG roadmap. The Muon Collider\u0000Study (MuC) covers the accelerator complex, detectors and physics for a future\u0000muon collider. In 2023, European Commission support was obtained for a design\u0000study of a muon collider (MuCol) [3]. This project started on 1st March 2023,\u0000with work-packages aligned with the overall muon collider studies. In\u0000preparation of and during the 2021-22 U.S. Snowmass process, the muon collider\u0000project parameters, technical studies and physics performance studies were\u0000performed and presented in great detail. Recently, the P5 panel [4] in the U.S.\u0000recommended a muon collider R&D, proposed to join the IMCC and envisages that\u0000the U.S. should prepare to host a muon collider, calling this their \"muon\u0000shot\". In the past, the U.S. Muon Accelerator Programme (MAP) [5] has been\u0000instrumental in studies of concepts and technologies for a muon collider.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"50 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Further improvement of medium temperature heat treated SRF cavities for high gradients","authors":"L. Steder, C. Bate, K. Kasprzak, D. Reschke, L. Trelle, H. Weise, M. Wiencek","doi":"arxiv-2407.12570","DOIUrl":"https://doi.org/arxiv-2407.12570","url":null,"abstract":"The application of heat treatments on 1.3 GHz TESLA type cavities in\u0000ultra-high vacuum at 250{deg}C to 350{deg}C is called medium temperature or\u0000mid-T heat treatment. In various laboratories such treatments on\u0000superconducting radio frequency (SRF) cavities result reproducible in three\u0000main characteristic features for the quality factor $Q_0$ in dependency of the\u0000accelerating electric field strength $E_{acc}$. First, comparing mid-T heat\u0000treatment with a baseline treatment, a significant increase of $Q_0$ up to\u0000$5cdot10^{10}$ at 2K can be observed. Second, with increasing accelerating\u0000gradient $E_{acc}$ the $Q_0$ increases up to a maximum around 16 to 20 MV/m.\u0000This effect is known as anti-Q-slope. The third observation for a mid-T heat\u0000treatment compared to a baseline treatment is an often reduced maximum gradient\u0000$E_{acc}$. The appearance of a high-field-Q-slope (HFQS) was reported after mid-T heat\u0000treatments of 3 hours at 350{deg}C or of 20 hours at 300{deg}C at DESY. Using\u0000the heating temperature and the heating time taken from the temperature profile\u0000of the furnace effective oxygen diffusion lengths $l$ were calculated. In the\u0000follow-up study presented here, a set of three single-cell cavities with\u0000diffusion lengths $l$ above 1700 nm, showing HFQS, were treated with an\u0000additional so-called low-T bake of 24-48 hours at 120{deg}C to 130{deg}C. The\u0000subsequent reproducible Q(E) -performances results indicate that the low-T bake\u0000procedure cures the HFQS like for cavities treated with the EuXFEL recipe of EP\u0000and following low-T treatments. As presented in the following, Q values of more\u0000than $3cdot10^{10}$ at 16 MV/m and accelerating gradients of 32 to 40 MV/m are\u0000achieved.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"64 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A structural analysis of ordered Cs$_{3}$Sb films grown on single crystal graphene and silicon carbide substrates","authors":"C. Pennington, M. Gaowei, E. M. Echeverria, K. Evans-Lutterodt, A. Galdi, T. Juffmann, S. Karkare, J. Maxson, S. J. van der Molen, P. Saha, J. Smedley, W. G. Stam, R. M. Tromp","doi":"arxiv-2407.12224","DOIUrl":"https://doi.org/arxiv-2407.12224","url":null,"abstract":"Alkali antimonides are well established as high efficiency, low intrinsic\u0000emittance photocathodes for accelerators and photon detectors. However,\u0000conventionally grown alkali antimonide films are polycrystalline with surface\u0000disorder and roughness that can limit achievable beam brightness. Ordering the\u0000crystalline structure of alkali antimonides has the potential to deliver higher\u0000brightness electron beams by reducing surface disorder and enabling the\u0000engineering of material properties at the level of atomic layers. In this\u0000report, we demonstrate the growth of ordered Cs$_{3}$Sb films on single crystal\u0000substrates 3C-SiC and graphene-coated 4H-SiC using pulsed laser deposition and\u0000conventional thermal evaporation growth techniques. The crystalline structures\u0000of the Cs$_{3}$Sb films were examined using reflection high energy electron\u0000diffraction (RHEED) and X-ray diffraction (XRD) diagnostics, while film\u0000thickness and roughness estimates were made using x-ray reflectivity (XRR).\u0000With these tools, we observed ordered domains in less than 10 nm thick films\u0000with quantum efficiencies greater than one percent at 530 nm. Moreover, we\u0000identify structural features such as Laue oscillations indicative of highly\u0000ordered films. We found that Cs$_{3}$Sb films grew with flat, fiber-textured\u0000surfaces on 3C-SiC and with multiple ordered domains and sub-nanometer surface\u0000roughness on graphene-coated 4H-SiC under our growth conditions. We identify\u0000the crystallographic orientations of Cs$_{3}$Sb grown on graphene-coated 4H-SiC\u0000substrates and discuss the significance of examining the crystal structure of\u0000these films for growing epitaxial heterostructures in future experiments.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Conditional Guided Generative Diffusion for Particle Accelerator Beam Diagnostics","authors":"Alexander Scheinker","doi":"arxiv-2407.10693","DOIUrl":"https://doi.org/arxiv-2407.10693","url":null,"abstract":"Advanced accelerator-based light sources such as free electron lasers (FEL)\u0000accelerate highly relativistic electron beams to generate incredibly short (10s\u0000of femtoseconds) coherent flashes of light for dynamic imaging, whose\u0000brightness exceeds that of traditional synchrotron-based light sources by\u0000orders of magnitude. FEL operation requires precise control of the shape and\u0000energy of the extremely short electron bunches whose characteristics directly\u0000translate into the properties of the produced light. Control of short intense\u0000beams is difficult due to beam characteristics drifting with time and complex\u0000collective effects such as space charge and coherent synchrotron radiation.\u0000Detailed diagnostics of beam properties are therefore essential for precise\u0000beam control. Such measurements typically rely on a destructive approach based\u0000on a combination of a transverse deflecting resonant cavity followed by a\u0000dipole magnet in order to measure a beam's 2D time vs energy longitudinal\u0000phase-space distribution. In this paper, we develop a non-invasive virtual\u0000diagnostic of an electron beam's longitudinal phase space at megapixel\u0000resolution (1024 x 1024) based on a generative conditional diffusion model. We\u0000demonstrate the model's generative ability on experimental data from the\u0000European X-ray FEL.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141717740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of solenoid lens field on electron beam emittance","authors":"Kazuaki Togawa","doi":"arxiv-2407.09081","DOIUrl":"https://doi.org/arxiv-2407.09081","url":null,"abstract":"In an injector system of an X-ray free electron laser (XFEL), solenoid lenses\u0000are typically used to confine low-emittance electron beams to low-energy region\u0000below a few MeV. Because non-thermionic emittance at such a low-energy region\u0000is easily deteriorated by nonlinear electromagnetic fields, it is important to\u0000determine the properties of a solenoid lens on electron beam emittance in the\u0000design of XFEL injectors. We derived an approximate solution to emittance\u0000growth due to lens aberration by a paraxial approximation. It was found that\u0000the derivative of the longitudinal magnetic field strongly affects beam\u0000emittance, and its growth is proportional to the fourth power of the beam\u0000radius. Various properties of the beam can be analyzed as long as the\u0000longitudinal magnetic field distribution is prepared using a simulation or\u0000measurement. In this study, a theoretical procedure to obtain the emittance\u0000growth in the solenoid lens is introduced and the design considerations of the\u0000solenoid lens of the SACLA injector are described.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"2012 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141717741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Commissioning of a compact multibend achromat lattice: A new 3 GeV synchrotron radiation facility","authors":"Shuhei Obara, Kota Ueshima, Takao Asaka, Yuji Hosaka, Koichi Kan, Nobuyuki Nishimori, Toshitaka Aoki, Hiroyuki Asano, Koichi Haga, Yuto Iba, Akira Ihara, Katsumasa Ito, Taiki Iwashita, Masaya Kadowaki, Rento Kanahama, Hajime Kobayashi, Hideki Kobayashi, Hideo Nishihara, Masaaki Nishikawa, Haruhiko Oikawa, Ryota Saida, Keisuke Sakuraba, Kento Sugimoto, Masahiro Suzuki, Kouki Takahashi, Shunya Takahashi, Tatsuki Tanaka, Tsubasa Tsuchiyama, Risa Yoshioka, Tsuyoshi Aoki, Hideki Dewa, Takahiro Fujita, Morihiro Kawase, Akio Kiyomich, Takashi Hamano, Mitsuhiro Masaki, Takemasa Masuda, Shinichi Matsubara, Kensuke Okada, Choji Saji, Tsutomu Taniuchi, Yukiko Taniuchi, Yosuke Ueda, Hiroshi Yamaguchi, Kenichi Yanagida, Kenji Fukami, Naoyasu Hosoda, Miho Ishii, Toshiro Itoga, Eito Iwai, Tamotsu Magome, Masaya Oishi, Takashi Ohshima, Chikara Kondo, Tatsuyuki Sakurai, Masazumi Shoji, Takashi Sugimoto, Shiro Takano, Kazuhiro Tamura, Takahiro Watanabe, Takato Tomai, Noriyoshi Azumi, Takahiro Inagaki, Hirokazu Maesaka, Sunao Takahashi, Takashi Tanaka, Shinobu Inoue, Hirosuke Kumazawa, Kazuki Moriya, Kohei Sakai, Toshio Seno, Hiroshi Sumitomo, Ryoichi Takesako, Shinichiro Tanaka, Ryo Yamamoto, Kazutoshi Yokomachi, Masamichi Yoshioka, Toru Hara, Sakuo Matsui, Toshihiko Hiraiwa, Hitoshi Tanaka, Hiroyasu Ego","doi":"arxiv-2407.08925","DOIUrl":"https://doi.org/arxiv-2407.08925","url":null,"abstract":"NanoTerasu, a new 3 GeV synchrotron light source in Japan, began user\u0000operation in April 2024. It provides high-brilliance soft to tender X-rays and\u0000covers a wide spectral range from ultraviolet to tender X-rays. Its compact\u0000storage ring with a circumference of 349 m is based on a four-bend achromat\u0000lattice to provide two straight sections in each cell for insertion devices\u0000with a natural horizontal emittance of 1.14 nm rad, which is small enough for\u0000soft X-rays users. The NanoTerasu accelerator incorporates several innovative\u0000technologies, including a full-energy injector C-band linear accelerator with a\u0000length of 110 m, an in-vacuum off-axis injection system, a four-bend achromat\u0000with B-Q combined bending magnets, and a TM020 mode accelerating cavity with\u0000built-in higher-order-mode dampers in the storage ring. This paper presents the\u0000accelerator machine commissioning over a half-year period and our\u0000model-consistent ring optics correction. The first user operation with a stored\u0000beam current of 160 mA is also reported. We summarize the storage ring\u0000parameters obtained from the commissioning. This is helpful for estimating the\u0000effective optical properties of synchrotron radiation at NanoTerasu.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141717742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Instantaneous and Retarded Interactions in Coherent Radiation","authors":"Zhuoyuan Liu, Xiujie Deng, Tong Li, Lixin Yan","doi":"arxiv-2407.08579","DOIUrl":"https://doi.org/arxiv-2407.08579","url":null,"abstract":"In coherent radiation of an ensemble of electrons, radiation field from\u0000electrons resonantly drives the other electrons inside to produce stimulated\u0000emission. The radiation reaction force on the electrons accounting for this\u0000stimulated radiation loss is classically described by the Lienard-Wiechert\u0000potential. Despite its being the foundation of beam physics for decades, we\u0000show that using the \"acceleration field'' in Lienard-Wiechert potential to\u0000describe radiative interactions leads to divergences due to its implicit\u0000dependence on instantaneous interactions. Here, we propose an alternative\u0000theory for electromagnetic radiation by decomposing the interactions into\u0000instantaneous part and retarded part. It is shown that only the retarded part\u0000contributes to the irreversible radiation loss and the instantaneous part\u0000describes the space charge related effects. We further apply this theory to\u0000study the coherent synchrotron radiation wake, which hopefully will reshape our\u0000understanding of coherent radiation and collective interactions.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141613842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correlation of srf performance to oxygen diffusion length of medium temperature heat treated cavities","authors":"C. Bate, K. Kasprzak, D. Reschke, L. Steder, L. Trelle, H. Weise, M. Wiencek, J. Wolff","doi":"arxiv-2407.07779","DOIUrl":"https://doi.org/arxiv-2407.07779","url":null,"abstract":"This comprehensive study, being part of the European XFEL R&D effort,\u0000elucidates the influence of medium temperature (mid-T) heat treatments between\u0000250{deg}C and 350{deg}C on the performance of 1.3~GHz superconducting\u0000radiofrequency (SRF) niobium cavities. Utilizing a refurbished niobium retort\u0000furnace equipped with an inter-vacuum chamber and cryopumps at DESY, we have\u0000embarked on an investigation to enhance the state-of-the-art SRF cavity\u0000technology. Our research reveals that mid-T heat treatments significantly boost\u0000the quality factor ($Q_0$) of the cavities, achieving values between\u0000$2cdot10^{10}$ to $5cdot10^{10}$ at field strengths around 16~MV/m, while the\u0000maximum field strengths are limited to 25-35~MV/m and enhanced sensitivity to\u0000trapped magnetic flux is observed. Moreover, we delve into the effects of\u0000surface impurity concentration changes, particularly the diffusion of oxygen\u0000content, and its impact on performance enhancements. By categorizing treatments\u0000based on calculated diffusion lengths using the whole temperature profile, we\u0000recognize patterns that suggest an optimal diffusion length conducive to\u0000optimizing cavity performance. SIMS results from samples confirm the calculated\u0000oxygen diffusion lengths in most instances. Deviations are primarily attributed\u0000to grain boundaries in fine-grain materials, necessitating repeated\u0000measurements on single-crystal materials to further investigate this\u0000phenomenon. Investigations into cooling rates and the resulting spatial\u0000temperature gradients across the cavities ranging from 0.04 to 0.2~K/mm reveal\u0000no significant correlation with performance following a mid-T heat treatment.\u0000However, the increased sensitivity to trapped magnetic flux leads to new\u0000challenges in the quest for next-generation accelerator technologies since the\u0000requirement for magnetic hygiene gets stricter.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141587310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}