skip to main content

Title: Vertical Instability at IPNS RCS.

The rapid cycling synchrotron (RCS) of the intense pulsed neutron source (IPNS) at ANL accelerates > 3.0 times 10{sup 12} protons from 50 MeV to 450 MeV with 30-Hz repetition frequency. During the acceleration cycle, the rf frequency varies from 2.21 MHz to 5.14 MHz. Presently, the beam current is limited by a vertical instability. By analyzing turn-by-turn beam position monitor (BPM) data, large- amplitude mode 0 and mode 1 vertical beam centroid oscillations were observed in the later part of the acceleration cycle. The oscillations start in the tail of the bunch, build up, and remain localized in the tail half of the bunch. This vertical instability was compared with a head-tail instability that was intentionally induced in the RCS by adjusting the trim sextupoles. It appears that our vertical instability is not a classical head-tail instability [1]. More data analysis and experiments were performed to characterize the instability.
Authors:
; ; ; ; ; ; ; ;  [1]
  1. (APS)
Publication Date:
OSTI Identifier:
972595
Report Number(s):
ANL/ASD/CP-59578
TRN: US1001640
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Conference
Resource Relation:
Conference: Particle Accelerator Conference (PAC07); Jun. 25, 2007 - Jun. 29, 2007; Albuquerque, NM
Publisher:
Proc., pp. 2022-2024
Research Org:
Argonne National Laboratory (ANL)
Sponsoring Org:
SC
Country of Publication:
United States
Language:
ENGLISH
Subject:
43 PARTICLE ACCELERATORS; ACCELERATION; ACCELERATORS; AMPLITUDES; ANL; BEAM CURRENTS; BEAM POSITION; DATA ANALYSIS; INSTABILITY; MONITORS; NEUTRON SOURCES; OSCILLATIONS; PROTONS; SYNCHROTRONS