Contribution to a conference proceedings/Contribution to a book

PUBDB-2025-02063

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Activities on Medium Grain Niobium at DESY

Reschke, D. (Corresponding author)DESY* ; Arnold, S.DESY* ; Bate, C.Extern*DESY* ; Ermakov, A.DESY* ; Ermakova, E.DESY* ; Goedecke, J. J.DESY* ; Iversen, J.DESY* ; Kasprzak, K.DESY* ; Muhs, A.DESY* ; Klinke, D.DESY* ; Steder, L.DESY* ; Thie, J.-H.DESY* ; Trelle, L.DESY* ; Wiencek, M.DESY*

2025
JACoW Publishing, Geneva, Switzerland
ISBN: 978-3-95450-256-1

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Please use a persistent id in citations: doi:10.18429/JACoW-SRF2025-THP32

Abstract: Within the ITN (ILC Technology Network) activity led by KEK, the so-called ”Medium Grain Niobium” is investigated with respect to its possible application for a large-scale SRF cavity production for the International Linear Collider ILC. In the framework of the KEK-DESY collaboration, the niobium material for two 1.3 GHz single-cell cavities was supplied by KEK. After fabrication and initial surface treatment by electropolishing in industry, the cavities have been tested successfully at DESY with gradients above 40 MV/m after an additional Low-T heat treatment. Subsequently, a heat treatment at medium temperatures around 350° C (Mid-T heat treatment) in the DESY furnace was applied. The vertical cryogenic test showed the typical performance after Mid-T heat treatment for both cavities. The Q-value increased up to (20 - 25) MV/m and achieved up to 3.5 · 10¹⁰. The maximum gradients were limited at 28 MV/m and 30 MV/m by breakdown, respectively. In addition, the effect of Ultra High Vacuum (UHV) heat treatments on state-of-the art fine grain niobium at temperatures between 800° C and 1100° C has been studied on samples with respect to grain growth, mechanical and thermal properties.

Note: Published by JACoW Publishing under the terms of the Creative Commons Attribution 4.0 license. Any further distribution of this work must maintain attribution to the author(s), the published article's title, publisher, and DOI.

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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)

Experiment(s):

1. Superconductivity Radio Frequency Research and Development

Appears in the scientific report 2025

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