CEBAF NEW DIGITAL LLRF SYSTEM EXTENDED FUNCTIONALITY

Conference · Mon Jun 18 04:00:00 EDT 2007

OSTI ID:908791

Allison, T; Davis, K; Dong, H; Hovater, C; King, L; Musson, J; Plawski, T

The new digital LLRF system for the CEBAF 12GeV accelerator will perform a variety of tasks, beyond field control [1]. In this paper we present the superconducting cavity resonance control system designed to minimize RF power during gradient ramp and to minimize RF power during steady state operation. Based on the calculated detuning angle, which represents the difference between reference and cavity resonance frequency, the cavity length will be adjusted with a mechanical tuner. The tuner has two mechanical driving devices, a stepper motor and a piezo-tuner, to yield a combination of coarse and fine control. Although LLRF piezo processing speed can achieve 10 kHz bandwidth, only 10 Hz speed is needed for 12 GeV upgrade. There will be a number of additional functions within the LLRF system; heater controls to maintain cryomodule's heat load balance, ceramic window temperature monitoring, waveguide vacuum interlocks, ARC detector interlock and quench detection. The additional functions will be divided between the digital board, incorporating an Altera FPGA and an embedded EPICS IOC. This paper will also address hardware evolution and test results performed with different SC cavities.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA
• Sponsoring Organization: USDOE - Office of Energy Research (ER)
• DOE Contract Number: AC05-06OR23177
• OSTI ID: 908791
• Report Number(s): JLAB-ACE-07-658; DOE/OR/23177-0063
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATORS
CAVITIES
CERAMICS
CONTROL SYSTEMS
DETECTION
HEATERS
INTERLOCKS
PROCESSING
RESONANCE
TEMPERATURE MONITORING
WAVEGUIDES
WINDOWS