R&D ERL: 5 Cell 704 MHz SRF Cavity

Burrill, A.

关键词: ACCELERATORS;    BEAM DUMPS;    BNL;    BRIGHTNESS;    CEBAF ACCELERATOR;    DESIGN;    ELECTRONS;    ENERGY RECOVERY;    ENERGY SYSTEMS;    LINEAR ACCELERATORS;    RF SYSTEMS;    RESONANCE;    SPECIFICATIONS;    SUPERCONDUCTING CAVITY RESONATORS;    TESTING relativistic;   

DOI  :  10.2172/1013453
RP-ID  :  BNL--90930-2010-IR
PID  :  OSTI ID: 1013453
Others  :  R&D Project: KBCH139
Others  :  Other: KB0202011
Others  :  TRN: US1102650

学科分类：核物理和高能物理

美国|英语

来源: SciTech Connect

【 摘 要 】

One of the key components for the superconducting RF Energy Recovery Linac, (ERL) under development in the Collider Accelerator Department at Brookhaven National Laboratory, is the Linac cavity and cryomodule. The cavity is a 5 cell accelerating cavity designed to operate at 703.75 MHz, and to accelerate 2 MeV electrons from the photoinjector up to 15-20 MeV, allow them to make a single pass around the ERL loop and then decelerate them back down to 2 MeV prior to sending them to the beam dump. This cavity was designed by Rama Calaga and Ilan Ben-Zvi at BNL and fabricated by Advanced Energy Systems in Medford, NY. The cavity was then delivered to Thomas Jefferson Laboratory in VA for chemical processing, testing and assembly of the hermetic string assembly suitable for shipment back to BNL. Once at BNL it was built into a complete cryomodule, installed in the ERL test facility and commissioned. This paper will review the key components of the cavity and cryomodule and discuss the present status of the cryomodule commissioning. The BNL 5 cell accelerating cavity has been designed for use in our high average current Energy Recovery Linac, a proof of principle machine to demonstrate key components necessary for the future upgrades to RHIC as well as applications for future ampere class high current, high brightness ERL programs. The cavity has been tested at greater than 20 MV/m with a Q{sub 0} of 1e{sup 10}, meeting the design specifications for use at full energy in the ERL. This paper will review the cavity design and specifications as well as the RF measurements that have been made both in the VTA at Jefferson Lab as well as during the commissioning in the ERL test cave at BNL. Finally the future plan for cavity testing and measurements prior to its use in ERL operations will be reviewed. The general physics parameters for the cavity can be found in table 1, and the reader is referred to Rama Calaga's Thesis for a much more detailed review of the cavity geometry and design. There are several different parameters that make this cavity design very unique. The first is the 17 cm diameter cavity iris and 24 cm diameter beampipe. The geometry, along with the cavity design, results in a cavity with no trapped higher order modes, and a BBU threshold is > 2 amperes. Another feature of the geometry of this particular cavity is the fact that the lowest mechanical resonance is at {approx}200 Hz, thus making it much less susceptible to microphonics.