Impedances of the shielded bellows in the SSC and the effects on beam stability
Abstract
The 1.08 km of bellows in Design A of the SSC (Superconducting Super Collider) will contribute to single-bunch instabilities: i.e., in transverse mode-coupling, bellow contribution Z bar (perpendicular) = 68 mega ohm/m, and allowance for stability Z bar (perpendicular) 120 mega ohm/m; in transverse microwave (for borad band at 13 GHz), bellow contribution Z (perpendicular) = 174 mega ohm/m, and allowance for stability Z (perpendicular) 1287 mega ohm/m; in longitudinal microwave, bellow contribution Z (parallel)/n = 2.3 ohms and allowance for stability Z (parallel)/n 4.7 ohms. In the above, it is assumed that an average single-bunch current I = 7.7 microA, RMS energy spread sigma sub E = 1.5x10 to the -4 power at injection energy of 1 TeV, RMS bunch length sigma sub iota = 7 cm, average betaron function beta bar = 150 m, and frequency slip actor eta = 1.3 x 10 to the -4th power. In order to support a stable bunch beam of the designed intensity, the bellow corrugations must be shielded. The shielding itself also must have low impedances.
- Publication:
-
Unknown
- Pub Date:
- July 1985
- Bibcode:
- 1985isbs.book.....N
- Keywords:
-
- Beams (Radiation);
- Bellows;
- Particle Accelerators;
- Particle Collisions;
- Shielding;
- Stability;
- Superconducting Super Collider;
- Superconductivity;
- Betatrons;
- Bunching;
- Impedance;
- Microwaves;
- Root-Mean-Square Errors;
- Nuclear and High-Energy Physics