Novel Geometries for the LHC Crab Cavity

Conference · Fri May 01 04:00:00 EDT 2009

OSTI ID:982427

Hall, B. ^[1]; Burt, G. ^[1]; Smith, J. D.A. ^[1]; Rimmer, R. ^[2]; Wang, H. ^[2]; Delayen, J. ^[2]; Calaga, R. ^[3]

---

1. Lancaster Univ. (United Kingdom)
2. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
3. Brookhaven National Lab. (BNL), Upton, NY (United States)

In 2017 the LHC is envisioned to increase its luminosity via an upgrade. This upgrade is likely to require a large crossing angle hence a crab cavity is required to align the bunches prior to collision. There are two possible schemes for crab cavity implementation, global and local. In a global crab cavity the crab cavity is far from the IP and the bunch rotates back and forward as it traverses around the accelerator in a closed orbit. For this scheme a two-cell elliptical squashed cavity at 800 MHz is preferred. To avoid any potential beam instabilities all the parasitic modes of the cavities must be damped strongly, however crab cavities have lower order and same order modes in addition to the usual higher order modes and hence a novel damping scheme must be used to provide sufficient damping of these modes. In the local scheme two crab cavities are placed at each side of the IP two start and stop rotation of the bunches. This would require crab cavities much smaller transversely than in the global scheme but the frequency cannot be increased any higher due to the long bunch length of the LHC beam. This will require a novel compact crab cavity design. A superconducting version of a two rod coaxial deflecting cavity as a suitable design is proposed in this paper.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC05-06OR23177
• OSTI ID: 982427
• Report Number(s): JLAB--ACC-09-955; DOE/OR/23177--3686
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATORS
CAVITIES
DAMPING
DESIGN
IMPLEMENTATION
LUMINOSITY
ROTATION