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Title: Testing of HOM coupler designs on a single cell niobium cavity

Conference ·
OSTI ID:839999

Coaxial higher order mode (HOM) couplers were developed initially for HERA cavities and subsequently for TESLA cavities. They were adopted later for SNS and Jlab upgrade cavities. The principle of operation is the rejection of the fundamental mode by the tunable filter and the transmission of the HOMs. It has been recognized recently that for continuous wave or high duty factor applications of the TESLA coupler the output pick-up probe must stay superconducting in order to avoid its heating by the fundamental mode residual magnetic field leading to deterioration of the cavity quality factor. In addition, the thermal conduction of existing rf feedthrough designs is only marginally sufficient to keep even the niobium probe tip superconducting in cw operation. We have equipped a single-cell niobium cavity with the modified HOM couplers and tested the new designs by measuring Q vs Eacc behavior at 2 K for different feedthroughs and probe tip materials.

Research Organization:
Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Sponsoring Organization:
USDOE; USDOE Office of Energy Research (ER) (US)
DOE Contract Number:
AC05-84ER40150
OSTI ID:
839999
Report Number(s):
JLAB-ACC-05-344; DOE/ER/40150-3361; TRN: US0501763
Resource Relation:
Conference: PAC 2005, Knoxville, TN (US), 05/16/2005--05/20/2005; Other Information: PBD: 1 May 2005
Country of Publication:
United States
Language:
English