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Title: The bellows at low beta and beam stabilities

Abstract

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.

Authors:
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
DOE/ER
OSTI Identifier:
7166508
Report Number(s):
FNAL-TM-1639
ON: DE90007233; TRN: 90-007111
DOE Contract Number:  
AC02-76CH03000
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; BELLOWS; ELECTRIC IMPEDANCE; BEAM BUNCHING; BEAM TRANSPORT; FERMILAB TEVATRON; INSTABILITY; ACCELERATORS; BEAM DYNAMICS; CYCLIC ACCELERATORS; IMPEDANCE; MECHANICAL STRUCTURES; SYNCHROTRONS; 430303* - Particle Accelerators- Experimental Facilities & Equipment

Citation Formats

Ng, King-Yuen. The bellows at low beta and beam stabilities. United States: N. p., 1989. Web. doi:10.2172/7166508.
Ng, King-Yuen. The bellows at low beta and beam stabilities. United States. https://doi.org/10.2172/7166508
Ng, King-Yuen. 1989. "The bellows at low beta and beam stabilities". United States. https://doi.org/10.2172/7166508. https://www.osti.gov/servlets/purl/7166508.
@article{osti_7166508,
title = {The bellows at low beta and beam stabilities},
author = {Ng, King-Yuen},
abstractNote = {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.},
doi = {10.2172/7166508},
url = {https://www.osti.gov/biblio/7166508}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Nov 01 00:00:00 EST 1989},
month = {Wed Nov 01 00:00:00 EST 1989}
}