CERN Accelerating science

Article
Title	Beam-Profile Instrumentation for a Beam-Halo Measurement : Overall Description, Operation, and Beam Data
Author(s)	Gilpatrick, J D ; Barr, D ; Day, L ; Kerstiens, D ; Stettler, M ; Valdiviez, R
Affiliation	(LANL, Los Alamos National Laboratory, Los Alamos, NM, USA HC, Honeywell Corporation, USA GAC, General Atomics Corporation, San Diego, CA, USA)
Publication	2001
In:	5th European Workshop on Diagnostics and Beam Instrumentation, Grenoble, France, 13 - 15 May 2001, pp.76
Subject category	Accelerators and Storage Rings
Abstract	The halo experiment presently being conducted at the Low Energy Demonstration Accelerator (LEDA) at Los Alamos National Laboratory (LANL) has specific instruments that acquire horizontally and vertically projected particle-density beam distributions out to greater than 105:1 dynamic range. We measure the core of the distributions using traditional wire scanners, and the tails of the distribution using water-cooled graphite scraping devices. The wire scanner and halo scrapers are mounted on the same moving frame whose location is controlled with stepper motors. A sequence within the Experimental Physics and Industrial Control System (EPICS) software communicates with a National Instrument LabVIEW virtual instrument to control the movement and location of the scanner/scraper assembly. Secondary electrons from the wire scanner 33 μm carbon wire and protons impinging on the scraper are both detected with a lossy-integrator electronic circuit. Algorithms implemented within EPICS and in Research Systems Interactive Data Language (IDL) subroutines analyse and plot the acquired distributions. This paper describes the beam profile instrument, describes our experience with its operation, compares acquired profile data with simulations, and discusses various beam profile phenomenon specific to the halo experiment.