skip to main content

Title: Electron proton two-stream instability at the PSR.

A strong, fast, transverse instability has long been observed at the Los Alamos Proton Storage Ring (PSR) where it is a limiting factor on peak intensity. Most of the available evidence, based on measurements of the unstable proton beam motion, is consistent with an electron-proton two-stream instability. The need for higher beam intensity at PSR [1] and for future high-intensity, proton drivers has motivated a multi-lab collaboration (LANL, ANL, FNAL, LBNL, BNL, ORNL, and PPPL) to coordinate research on the causes, dynamics and cures for this instability. Important characteristics of the electron cloud were recently measured with retarding field electron analyzers and various collection electrodes. Suppression of the electron cloud formation by TiN coatings has confirmed the importance of secondary emission processes in its generation. New tests of potential controls included dual harmonic rf, damping by higher order multipoles, damping by X,Y coupling and the use of inductive inserts to compensate longitudinal space charge forces. With these controls and higher rf voltage the PSR has accumulated stable beam intensity up to 9.7 {micro}C/pulse (6 x 10{sup 13} protons), which is a 60% increase over the previous maximum.
Authors:
; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
OSTI Identifier:
793052
Report Number(s):
ANL/ASD/CP-106950
TRN: US0200900
DOE Contract Number:
W-31-109-ENG-38
Resource Type:
Conference
Resource Relation:
Conference: 2001 Particle Accelerator Conference (PAC 2001), Chicago, IL (US), 06/18/2001--06/22/2001; Other Information: PBD: 19 Feb 2002
Research Org:
Argonne National Lab., IL (US)
Sponsoring Org:
US Department of Energy (US)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ACCELERATORS; ELECTRONS; INSTABILITY; PROTON BEAMS; PROTONS; SECONDARY EMISSION; SPACE CHARGE; STORAGE RINGS; TWO-STREAM INSTABILITY