Author: Grau, A.W.
Paper Title Page
TUPAB267 Investigation of Beam Impedance and Heat Load in a High Temperature Superconducting Undulator 2089
 
  • D. Astapovych, H. De Gersem, E. Gjonaj
    TEMF, TU Darmstadt, Darmstadt, Germany
  • T.A. Arndt, E. Bründermann, N. Glamann, A.W. Grau, B. Krasch, A.-S. Müller, R. Nast, D. Saez de Jauregui, A. Will
    KIT, Karlsruhe, Germany
  
  The use of high tem­per­a­ture su­per­con­duct­ing (HTS) ma­te­ri­als can en­hance the per­for­mance of su­per­con­duct­ing un­du­la­tors (SCU), which can later be im­ple­mented in free elec­tron laser fa­cil­i­ties, syn­chro­tron stor­age rings and light sources. In par­tic­u­lar, the short pe­riod < 10 mm un­du­la­tors with nar­row mag­netic gap < 4 mm are rel­e­vant. One of the promis­ing ap­proaches con­sid­ers a 10 cm me­an­der-struc­tured HTS tapes stacked one above the other. Then, the HTS tape is wound on the SCU. The idea of this joint­less un­du­la­tor has been pro­posed by, and is being fur­ther de­vel­oped at KIT. Since min­i­miz­ing the dif­fer­ent sources of heat load is a crit­i­cal issue for all SCUs, a de­tailed analy­sis of the im­ped­ance and heat load is re­quired to meet the cryo­genic sys­tem de­sign. The dom­i­nant heat source is an­tic­i­pated to be the re­sis­tive sur­face loss, which is one of the sub­jects of this study. Con­sid­er­ing the com­plex­ity of the HTS tape, the im­ped­ance model in­cludes the geo­met­ri­cal struc­ture of the HTS tapes as well as the anom­alous skin ef­fect. The re­sults of the nu­mer­i­cal in­ves­ti­ga­tion per­formed by the help of the CST PS solver will be pre­sented and dis­cussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB267  
About • paper received ※ 18 May 2021       paper accepted ※ 26 July 2021       issue date ※ 12 August 2021  
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TUPAB270 Thermal Transition Design and Beam Heat-load Estimation for the COLDDIAG Refurbishment 2097
 
  • H.J. Cha, N. Glamann, A.W. Grau, A.-S. Müller, D. Saez de Jauregui
    KIT, Eggenstein-Leopoldshafen, Germany
  
  Funding: This work is supported by the BMBF project 05H18VKRB1 HIRING (Federal Ministry of Education and Research).
The COLD­DIAG (cold vac­uum cham­ber for beam heat load di­ag­nos­tics) de­vel­oped at Karl­sruhe In­sti­tute of Tech­nol­ogy has been mod­i­fied for more stud­ies at cryo­genic tem­per­a­tures dif­fer­ent from the pre­vi­ous op­er­a­tions at 4 K in a cold bore and at 50 K in a ther­mal shield. The key com­po­nents in this cam­paign are two ther­mal tran­si­tions con­nect­ing both ends of the bore at 50 K with the shield at the same or higher tem­per­a­ture. In this paper, we pre­sent de­sign ef­forts for the com­pact tran­si­tions, al­lowed heat in­takes to the cool­ing power mar­gin and me­chan­i­cal ro­bust­ness in the cryo­genic en­vi­ron­ment. A man­u­fac­ture scheme for the tran­si­tion and its pe­riph­eral is also given. In ad­di­tion, the beam heat loads in the re­fur­bished COLD­DIAG are es­ti­mated in terms of the ac­cel­er­a­tor beam pa­ra­me­ters. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB270  
About • paper received ※ 12 May 2021       paper accepted ※ 02 June 2021       issue date ※ 12 August 2021  
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WEPAB135 Progress of the Development of a Superconducting Undulator as a THz Source for FELs 2933
 
  • J. Gethmann, S. Casalbuoni, N. Glamann, A.W. Grau, A.-S. Müller, D. Saez de Jauregui
    KIT, Eggenstein-Leopoldshafen, Germany
  • D. Astapovych, H. De Gersem, E. Gjonaj
    TEMF, TU Darmstadt, Darmstadt, Germany
  • S. Casalbuoni
    EuXFEL, Schenefeld, Germany
  
  Funding: This work is supported by the BMBF project 05K19VK2 SCUXFEL (Federal Ministry of Education and Research) and by the DFG-funded Doctoral School KSETA: Science and Technology.
To pro­duce ra­di­a­tion in the THz fre­quency range at X-ray Free Elec­tron Lasers, un­du­la­tors with large pe­riod length, high fields, and large gaps are re­quired. These de­mands can be ful­filled by su­per­con­duct­ing un­du­la­tors. In this con­tri­bu­tion, the ac­tual re­quire­ments on the main pa­ra­me­ters of such a su­per­con­duct­ing un­du­la­tor will be dis­cussed and the progress of the de­sign will be dis­cussed. In ad­di­tion, beam im­ped­ance and heat load re­sults ob­tained an­a­lyt­i­cally as well as by large-scale wake­field sim­u­la­tions will be pre­sented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB135  
About • paper received ※ 19 May 2021       paper accepted ※ 02 July 2021       issue date ※ 31 August 2021  
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THPAB048 Design and Fabrication Concepts of a Compact Undulator with Laser-Structured 2G-HTS Tapes 3851
 
  • A. Will, T.A. Arndt, E. Bründermann, N. Glamann, A.W. Grau, B. Krasch, A.-S. Müller, R. Nast, D. Saez de Jauregui
    KIT, Eggenstein-Leopoldshafen, Germany
  • D. Astapovych, H. De Gersem, E. Gjonaj
    TEMF, TU Darmstadt, Darmstadt, Germany
  
  To pro­duce small-scale high-field un­du­la­tors for table-top free elec­tron lasers (FELs), com­pact de­signs have been pro­posed using high tem­per­a­ture su­per­con­duct­ing (HTS) tapes, which show both large crit­i­cal cur­rent den­si­ties and high crit­i­cal mag­netic fields with a total tape thick­ness of about 50 μm and a width of up to 12 mm. In­stead of wind­ing coils, a me­an­der struc­ture can be laser-scribed di­rectly into the su­per­con­duc­tor layer, guid­ing the cur­rent path on a quasi-si­nu­soidal tra­jec­tory. Stack­ing pairs of such scribed tapes al­lows the gen­er­a­tion of the de­sired si­nu­soidal mag­netic fields above the tape plane, along the tape axis. Two prac­ti­cally fea­si­ble de­signs are pre­sented, which are cur­rently under con­struc­tion at KIT: A coil con­cept wound from a sin­gle struc­tured tape with a length of 15 m, which is a pro­gres­sion of a de­sign that has been pre­sented al­ready in the past, as well as a novel stacked and sol­dered de­sign, made from 25 cm long struc­tured tapes, sol­dered in a zig-zag-pat­tern. In this con­tri­bu­tion the de­signs are briefly re­capped and the ex­per­i­men­tal progress is pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB048  
About • paper received ※ 19 May 2021       paper accepted ※ 12 July 2021       issue date ※ 15 August 2021  
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THPAB126 Operational Experience and Characterization of a Superconducting Transverse Gradient Undulator for Compact Laser Wakefield Accelerator-Driven FEL 4009
 
  • K. Damminsek, A. Bernhard, J. Gethmann, A.W. Grau, A.-S. Müller, Y. Nie, M.S. Ning, S.C. Richter, R. Rossmanith
    KIT, Karlsruhe, Germany
  
  A 40-pe­riod su­per­con­duct­ing trans­verse gra­di­ent un­du­la­tor (TGU) has been de­signed and fab­ri­cated at Karl­sruhe In­sti­tute of Tech­nol­ogy (KIT). Com­bin­ing a TGU with a Laser Wake­field Ac­cel­er­a­tor (LWFA) is a po­ten­tial key for re­al­iz­ing an ex­tremely com­pact Free Elec­tron Laser (FEL) ra­di­a­tion source. The TGU scheme is a vi­able op­tion to com­pen­sate the chal­leng­ing prop­er­ties of the LWFA elec­tron beam in terms of beam di­ver­gence and en­ergy spread. In this con­tri­bu­tion, we re­port on the op­er­a­tional ex­pe­ri­ence of this TGU in­side its own cryo­stat and show the cur­rent sta­tus of the TGU and the fur­ther plan for ex­per­i­ments. This work is sup­ported by the BMBF pro­ject 05K19VKA Plas­maFEL (Fed­eral Min­istry of Ed­u­ca­tion and Re­search).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB126  
About • paper received ※ 19 May 2021       paper accepted ※ 25 August 2021       issue date ※ 02 September 2021  
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