Higher-Order-Mode damping and microwave absorption at 2K
A special ceramic material for microwave absorption at low temperature has been developed at CEBAF to manufacture the 676 Higher-Order-Mode (HOM) loads for the machine. The accelerator includes 338 5-cell niobium cavities, resonating in the fundamental TM{sub 010}{pi} mode at 1497 MHs, in two antiparallel linacs (160 cavities each) and an injector (18 cavities). Higher-Order-Mode (HOM) power generation in the machine is expected to be in the tens of milliwatts per cavity at the nominal beam current of 200 {mu}A. This amount of power constitutes a small fraction of the power dissipated by the superconducting cavities at the operating gradient of 5 MV/m (typically less than 5 W per cavity) and the HOM power is more efficiently absorbed at the bat temperature of 2K than at room temperature. The HOM extraction is done via two S-band waveguides located orthogonally to each other at one end of the cavities and a load is placed at the end of each waveguide. This HOM damping scheme is characteristic of CEBAF alone: the low operating temperature and the vacuum in common with the superconducting cavities prevent the use of standard absorbers. Totally new materials and a novel absorber shape were developed for this application. 9 refs.
- Research Organization:
- Southeastern Universities Research Association, Inc., Newport News, VA (United States). Continuous Electron Beam Accelerator Facility
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 10160568
- Report Number(s):
- DOE/ER/40150-188; CEBAF-PR-92-010; CONF-920315-41; ON: DE92016960
- Resource Relation:
- Other Information: PBD: Mar 1992
- Country of Publication:
- United States
- Language:
- English
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