The bellows at low beta and beam stabilities
The Tevatron dipoles and quadrupoles are at superconducting temperature while the low-beta insertion is at room temperature. In order to limit the heat flowing into the low temperature region, the low-beta insertion is joined to the ring through a special bellows. The beam-pipe radius is 3.7 cm corresponding to a cutoff frequency of 3.10 GHz for the monopole mode and 2.38 GHz for the dipole mode. There are approximately 32 such bellows. Each bellows has a narrow gap of about 6 mm at the beam pipe and opens up into a {approximately} 7 cm wide cavity at larger radius. The bellows ripples start at a radius of about 12 cm. We therefore expect the bellows to contribute sharp resonances below cutoff at frequency below 1 GHz. In this article, we are going to compute the longitudinal and transverse impedances and to check whether they can drive any collective instabilities of the beam bunches. 4 figs., 3 tabs.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- DOE/ER
- DOE Contract Number:
- AC02-76CH03000
- OSTI ID:
- 7166508
- Report Number(s):
- FNAL-TM-1639; ON: DE90007233; TRN: 90-007111
- Country of Publication:
- United States
- Language:
- English
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