Journal Article

PUBDB-2025-03653

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Multiphysics Analysis of Cryogenically Cooled Photocathode in a CW SRF Injector cavity

Bazyl, D. (Corresponding author)DESY* ; Floettmann, K.DESY* ; Vogel, E.DESY* ; Zagorodnov, I.DESY*

2025
American Physical Society College Park, MD

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Please use a persistent id in citations: doi:10.1103/9jyv-hfxy  doi:10.3204/PUBDB-2025-03653

Report No.: arXiv:2508.11764

Abstract: The paper evaluates the thermal regime of a cryogenically cooled copper photocathode integrated into a continuous-wave superconducting radio-frequency injector cavity with direct thermal contact. Such a photoinjector layout is being developed at DESY and has recently demonstrated a record high 50 MV/m axial electric field in radio-frequency tests, marking an important milestone. To address the thermal effect of the picosecond excitation laser, we first develop a two-temperature model to describe the temperature of the emitting surface at cryogenic temperatures and solve it numerically. Subsequently, we present a one-temperature model of the bulk photocathode coupled with an electromagnetic model of the injector cavity. For the current injector design, we predict a negligible impact of the laser on the intrinsic quality factor of the cavity, identifying instead the cryogenic stability of the copper cathode as the primary operational limit. To overcome cooling challenges, we propose an improved configuration of the cathode plug. For the proposed geometry, the multiphysics analysis confirms stable performance at a nominal 2 W laser power, sufficient for 100 pC beams at 1 MHz under optimistic quantum efficiency assumptions. Operation at higher laser loads will benefit from further dedicated cryogenic analysis.

Note: preprint:643478

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Contributing Institute(s):

1. Supraleitende Beschleuniger Technologie (MSL)

Research Program(s):

1. 621 - Accelerator Research and Development (POF4-621) (POF4-621)
2. 6G13 - Accelerator of European XFEL (POF4-6G13) (POF4-6G13)

Experiment(s):

1. Facility (machine) XFEL

Appears in the scientific report 2025

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DOAJ Seal ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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Linked articles:

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Preprint Bazyl, D. (Corresponding author)DESY* ; Floettmann, K.DESY* ; Vogel, E.DESY* ; Zagorodnov, I.DESY*
Multiphysics Analysis of Cryogenically Cooled Photocathode in a CW SRF Injector cavity
[10.3204/PUBDB-2026-00225]     Files  Fulltext by arXiv.org BibTeX | EndNote: XML, Text | RIS

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