A Non-invasive Technique for Configuring Low Level RF Feedback Loops in PEP-II

Conference · Wed Jun 22 04:00:00 EDT 2005

OSTI ID:890303

Teytelman, D

The RF system of the PEP-II collider uses two fast feedback loops around each klystron and set of cavities. These loops reduce the impedance of the fundamental mode of the accelerating cavities seen by the beam, and are necessary to reduce the growth rates of longitudinal modes within the RF system bandwidth. Operation of the accelerator at high beam currents is very sensitive to the configuration of the low-level RF feedback loops. There are 7 loop control parameters that strongly influence the stability of the feedback loops and the achieved level of longitudinal impedance reduction. Diagnostic techniques for the analysis of the RF feedback via closed-loop system transfer function measurements will be presented. The model is fit to the measured closed-loop transfer function data and the extracted parameters are then used to calculate optimal tuning and corrections to the loop control elements in the physical channel. These techniques allow fine-tuning of RF feedback with stored beam as well as diagnosis of misconfigured or malfunctioning elements of the system. Results from PEP-II operation will be presented to illustrate the techniques and their applications.

• Research Organization: Stanford Linear Accelerator Center (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 890303
• Report Number(s): SLAC-PUB-11252
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATORS
Accelerators
INST
BEAM CURRENTS
CAVITIES
CONFIGURATION
CONTROL ELEMENTS
DIAGNOSIS
DIAGNOSTIC TECHNIQUES
FEEDBACK
IMPEDANCE
KLYSTRONS
RF SYSTEMS
STABILITY
TRANSFER FUNCTIONS
TUNING