Report/Contribution to a conference proceedings

PUBDB-2016-02947

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Hydro Forming of TESLA Cavities at DESY

Singer, W. (Corresponding author)DESY* ; Kaiser, H. ; Singer, X.DESY* ; Gonin, I. ; Zhelezov, I. ; Khabibullin, T. ; Kneisel, P. ; Saito, K.

2000
DESY Hamburg

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Please use a persistent id in citations: doi:10.3204/PUBDB-2016-02947

Report No.: DESY-M-00-04ZC; JLAB-ACC-00-20

Abstract: Since several years the development of seamless niobium cavity fabrication by hydro forming is being pursued at DESY. This technique offers the possibility of lower cost of fabrication and perhaps better rfperformance of the cavities because of the elimination of electron-beam welds, which in the standard fabrication technique have sometimes lead to inferior cavity performance due to defects. Several single cell 1300 MHz cavities have been formed from high purity seamless niobium tubes, which are under computer control expanded with internal pressure while simultaneously being swaged axially. The seamless tubes have been made by either back extrusion and flow forming or by spinning or deep drawing. Standard surface treatment techniques such as high temperature post purification, buffered chemical polishing(BCP), electropolishing (EP) and high pressure ultra pure water rinsing (HPR) have been applied to these cavities. The cavities exhibited high Q - values of 2 x 10$^10$ at 2K and residual resistances as low as 3 n$\Omega$ after the removal of a surface layer of app. 100 $\mu$m by BCP. Surprisingly, even at high gradients up to the maximum measured values of E$_{acc}$ $\approx$ 33 MV/m the Q-value did not decrease in the absence of field emission as often observed. After electropolishing of additional 100 $\mu$m one of the cavities reached an accelerating gradient of E$_{acc}$ $\geq$ 42 MV/m.

Keyword(s): talk: Vienna 2000/06/26 ; RF system: superconductivity ; RF system: fabrication ; niobium ; RF system: surface ; RF system: impedance ; electric field: upper limit ; electron positron: linear collider ; linear collider: proposed ; DESY TESLA Linac

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Contributing Institute(s):

1. M-Bereich (M(-2012))

Research Program(s):

1. No facility / HGF program None (POF1-890) (POF1-890)

Experiment(s):

1. No specific instrument

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Linked articles:

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Proceedings/Report Decking, W. (Corresponding author)DESY*
Contributions to the 7th European Particle Accelerator Conference EPAC 2000
2000The 7th European Particle Accelerator Conference EPAC 2000, EPAC 2000, ViennaVienna, Austria, 26 Jun 2000 - 30 Jun 20002000-06-262000-06-30 Hamburg : DESY (2000)2000     Fulltext BibTeX | EndNote: XML, Text | RIS

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