THOPA —  Oral Poster session   (01-Sep-22   15:00—16:00)
Paper Title Page
A Ground Experimental Approach Toward Understanding Mysterious Astrophysical Fast Radio Bursts  
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  • Y. Sumitomo, T. Asai, D. Kobayashi, S. Kumagai, K. Kusaka, Y. Onishi, T. Seki, R. Yanagi
    Nihon University, Tokyo, Japan
  • Y. Hayakawa, T. Sakai
    LEBRA, Funabashi, Japan
  • S. Kisaka
    HU ADSE, Hiroshima, Japan
  • H. Koguchi
    AIST, Tsukuba, Japan
  Funding: Nihon University CST Project Research Grant (2021 Apr. ~), Japan Society for the Promotion of Science (JSPS), Grant-in-Aid for Scientific Research (KAKENHI), Grant Number JP19K12631
The Fast Radio Bursts are astrophysical events that get much more attentions increasing year by year, due to their mysterious properties of signals. The major properties of signals include a class of the brightest astrophysical events, short durations of emissions, and larger dispersion measures than the known short duration events. Interestingly, the large values of dispersion measures suggest the existence of abundant plasma around the parent bodies of emissions. To have a better understanding of basic mechanism of the Fast Radio Burst emissions, we initiated a ground-based research project at our 100 MeV electron LINAC facility, in combination with the high-beta plasma generation knowledge matured also at Nihon University, that mimics plasma fields in space. In this presentation, we overview our project and report on the status of the experiment for the induced enhanced emissions from integrated iterative interactions with plasma fields.
slides icon Slides THPOJO22 [0.678 MB]  
DOI • reference for this paper ※  
About • Received ※ 22 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 23 September 2022
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Methods for VHEE/FLASH Radiotherapy Studies and High Dose Rate Dosimetry at the CLEAR User Facility  
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  • P. Korysko
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
  • J.J. Bateman, C.S. Robertson
    JAI, Oxford, United Kingdom
  • R. Corsinipresenter, L.A. Dyks, W. Farabolini, V. Rieker
    CERN, Meyrin, Switzerland
  The interest for Very High Energy Electron (VHEE) radiotherapy (RT) for cancer treatment recently bloomed, given the present availability of high-gradient accelerator technology for compact, cost effective electron linacs in the 100-200 MeV energy range. Particularly promising is the so called FLASH high dose rate regime, in which cancer cells are damaged while healthy tissue is largely spared. VHEE beams are especially adapted for FLASH RT, given their penetration depth and the high beam current, needed to treat large deep seated tumors. In the CERN Linear Accelerator for Research (CLEAR) facility, a series of unique studies have been initiated on VHEE and FLASH RT issues, in collaboration with several multidisciplinary user groups. In this paper we briefly outline the activities and its main recent results, e.g. on localized dose deposition by beam focusing, and on chemical and biological test to clarify damage mechanisms. We then describe in details the dedicated systems and the techniques adopted - and in large part locally developed by the CLEAR team - in order to satisfy the user requirements, with particular attention to the crucial aspect of high dose rate dosimetry.  
slides icon Slides THPOPA06 [1.183 MB]  
DOI • reference for this paper ※  
About • Received ※ 24 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 16 October 2022
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Medium Temperature Treatments of Superconducting Radio Frequency Cavities at DESY  
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  • L. Steder, C. Bate, H. Remde, D. Reschke, J. Schaffran, L. Trelle, H. Weise, M. Wiencek
    DESY, Hamburg, Germany
  • M. Wenskat
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  Over the last years several different approaches to increase the performance of superconducting radio frequency (SRF) cavities by heat treatments have been developed and tested. At DESY, the R&D aims for cavities with enlarged quality factors while maintaining high accelerating gradients, since an envisaged upgrade of the European XFEL requires both. For this purpose, medium temperature (mid-T) treatments around 300 °C seem to be very promising. Lately, the furnace infrastructure at DESY was refurbished and now a niobium-retort furnace capable of carrying 1.3 GHz nine-cell cavities can be used for R&D studies. Vertical test results of single-cell cavities treated in this furnace at medium temperatures are presented and compared to four cavities treated similarly in a furnace at the company Zanon Research & Innovation Srl (Zanon). All mentioned cavities show enlarged quality factors but at the same time reduced gradients compared to their reference measurements before the mid-T treatment. The DESY treatments were accompanied by small niobium samples for surface analyses, which are also presented. Furthermore, the influence of post-treatment high pressure water rinsings is studied.  
slides icon Slides THPOGE22 [1.277 MB]  
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About • Received ※ 20 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 27 August 2022 — Issue date ※ 15 September 2022
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Vertical Electro-Polishing of 704 MHz Resonators Using Ninja Cathode: Gradients Over 40 MV/m Achieved on ESS Single-Cell Cavity  
THPOGE23   use link to access more material from this paper's primary paper code  
  • F. Éozénou, M. Baudrier, E. Cenni, E. Fayette, L. Maurice, C. Servouin
    CEA-DRF-IRFU, France
  • H. Hayano, H. Ito, S. Kato, T. Kubo, H. Monjushiro, T. Saeki
    KEK, Ibaraki, Japan
  • Y.I. Ida, K. Nii, T.Y. Yamaguchi
    MGH, Hyogo-ken, Japan
  • G. Jullien
    CEA-IRFU, Gif-sur-Yvette, France
  CEA, KEK and Marui Galvanizing Company have been collaborating to apply the Vertical Electropolishing (VEP) process of elliptical SRF cavities to a 704MHz single-cell ESS-type cavity, using a rotating so called and patented "Ninja" cathode. First presented results* were promising with a gradient of 27MV/m achieved, without any heat treatment applied. The performance has been pushed further since. The cavity has undergone a heat treatment at 650°C during 10h, followed by a final VEP sequence and a baking at 120°C during 48h hours. The achieved gradient at 2K was 44MV/m (power limitation), and the quality factor Q0 exceeding 5·1010 up to 10 MV/m. The superiority of VEP compared to standard "BCP" chemical treatment is demonstrated and we intend now to scale the process to 5-Cell β=0.86 ESS cavity. We also intend to push further the performance by applying "2-step baking" (75°C and 120°C) proposed by FNAL, which was successfully applied at CEA Saclay on 1300MHz single-cell resonators with gradients above 50MV/m achieved after VEP bulk treatment.
* TUPCAV001, SRF 2021
slides icon Slides THPOGE23 [0.868 MB]  
poster icon Poster THPOGE23 [0.918 MB]  
DOI • reference for this paper ※  
About • Received ※ 24 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 09 September 2022 — Issue date ※ 16 September 2022
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Machine Learning Assisted Cavity Quench Identification at the European XFEL  
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  • J. Branlard, A. Eichler, J.H.K. Timm, N. Walker
    DESY, Hamburg, Germany
  A server-based quench detection system is used since the beginning of operation at the European XFEL (2017) to stop driving superconducting cavities if they experience a quench. While this approach effectively detects quenches, it also generates false positives, tripping the accelerating stations when failures other than quenches occur. Using the post-mortem data snapshots generated for every trip, an additional signal (referred to as residual) is systematically computed based on the standard cavity model. Following an initial training on a set of such residuals derived from quench as well as non-quench events, two independent machine learning engines analyze routinely the trip snapshots and their residuals to identify if a trip was indeed triggered by a quench or has another root cause. The outcome of the analysis is automatically appended to the data snapshots and distributed to a team of experts. This constitutes a fully deployed example of machine-learning-assisted failure classification to identify quenches, supporting experts in their daily routine of monitoring and documenting the accelerator uptime and availability.  
slides icon Slides THPOPA26 [0.695 MB]  
poster icon Poster THPOPA26 [0.975 MB]  
DOI • reference for this paper ※  
About • Received ※ 19 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 01 September 2022
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HSMDIS Performance on the ESS Ion Source  
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  • L. Neri, G. Castro, L. Celona, S. Gammino, O. Leonardi, A. Miraglia
    INFN/LNS, Catania, Italy
  • C. Baltador, L. Bellan, M. Comunian, F. Grespan
    INFN/LNL, Legnaro (PD), Italy
  • B. Jones, E. Laface, R. Miyamoto, A.G. Sosa
    ESS, Lund, Sweden
  The ESS ion source, developed at INFN-LNS and installed at the ESS facility, is fully working and in operation for the linac beam commissioning. The commissioning of the source was done in Catania and in Lund showing high reproducibility related to the beam diagnostic parameters that can be measured with the subset of equipment currently available in Lund. The analysis of the data collected during the commissioning in Catania discloses the possibility to use a new source configuration named High Stability Microwave Discharge Ion Source (HSMDIS), able to improve beam stability and lower the beam emittance. This paper shows the capability to increase the beam current intensity, with preserving beam stability, by changing only the microwave power. Linearity was tested from 10 to 120 mA to be able to provide the lower values needed for the different phases of the accelerator commissioning and higher values for future accelerator development. The source stability is evaluated through intra-pulse stability and pulse-to-pulse stability.
L. Neri, L. Celona "High stability microwave discharge ion sources" Sci Rep 12, 3064 (2022).
slides icon Slides THPORI19 [37.408 MB]  
DOI • reference for this paper ※  
About • Received ※ 24 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 16 September 2022
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