Advanced

Aperture and lifetime measurements with moveable scrapers at MAX II

Wallén, Erik LU (2003) In Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment 508(3). p.487-495
Abstract
A set of measurement with moveable aperture restrictions, also called scrapers, has been carried out at MAX II (Nucl. Instr. and Meth. A 343 (1994) 644), the 1.5GeV electron storage ring at MAX-lab, Lund, Sweden. The measurements with scrapers in MAX 11 have shown to give a number of useful results, such as the vertical and horizontal acceptance, which are 7.4 x 10(-6) and 9.6 x 10-6 m, respectively, the lifetime limitations due to scattering on residual gas in the vacuum system, the Touschek effect and the quantum effect. The vertical acceptance of MAX 11 corresponds to a total vertical aperture of 10.04 mm and a total horizontal aperture of 22.4 mm at the position of the scraper, i.e. in the straight sections. The lifetime in MAX II at... (More)
A set of measurement with moveable aperture restrictions, also called scrapers, has been carried out at MAX II (Nucl. Instr. and Meth. A 343 (1994) 644), the 1.5GeV electron storage ring at MAX-lab, Lund, Sweden. The measurements with scrapers in MAX 11 have shown to give a number of useful results, such as the vertical and horizontal acceptance, which are 7.4 x 10(-6) and 9.6 x 10-6 m, respectively, the lifetime limitations due to scattering on residual gas in the vacuum system, the Touschek effect and the quantum effect. The vertical acceptance of MAX 11 corresponds to a total vertical aperture of 10.04 mm and a total horizontal aperture of 22.4 mm at the position of the scraper, i.e. in the straight sections. The lifetime in MAX II at the measurement with 180mA of stored beam at full energy, 1.5GeV, was 23.8h. The 23.8h of lifetime is the total lifetime which is determined by the following lifetime limiting effects: Touschek effect 37 h, quantum effect >>100 h, elastic scattering on the residual gas 134 h, and inelastic scattering on the residual gas 132 h. It has shown possible to inject into and ramp the MAX II storage ring with a total vertical aperture in the straight sections as small as 9.34 mm. The measurements have shown that it is possible to install an insertion device in MAX II with a 10mm aperture without decreasing the beam lifetime, provided that the insertion devices do not deteriorate the vacuum situation. The gas mixture of the residual gas in the MAX II storage ring at operation has been measured and the absolute gas pressure is given by the results from the scraper measurements. In MAX II, as in most accelerators, the residual gas is dominated by hydrogen. The residual gas pressure in MAX II with 180 mA of stored beam at 1.5 GeV was 5.24 x 10(-9) Torr and it consists of 96.5% H-2, 1.1% H2O, 1.8% CO, and 0.6% CO2. (C) 2003 Elsevier B.V. All rights reserved. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Touschek effect, aperture, acceptance, scattering, accelerator vacuum, beam lifetime
in
Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment
volume
508
issue
3
pages
487 - 495
publisher
Elsevier
external identifiers
  • wos:000184660500030
  • scopus:0041743941
ISSN
0167-5087
DOI
10.1016/S0168-9002(03)01650-4
language
English
LU publication?
yes
id
d96fa4df-edfe-4099-b3e2-260543c6cdfb (old id 303792)
date added to LUP
2007-09-23 14:27:18
date last changed
2018-01-07 09:34:20
@article{d96fa4df-edfe-4099-b3e2-260543c6cdfb,
  abstract     = {A set of measurement with moveable aperture restrictions, also called scrapers, has been carried out at MAX II (Nucl. Instr. and Meth. A 343 (1994) 644), the 1.5GeV electron storage ring at MAX-lab, Lund, Sweden. The measurements with scrapers in MAX 11 have shown to give a number of useful results, such as the vertical and horizontal acceptance, which are 7.4 x 10(-6) and 9.6 x 10-6 m, respectively, the lifetime limitations due to scattering on residual gas in the vacuum system, the Touschek effect and the quantum effect. The vertical acceptance of MAX 11 corresponds to a total vertical aperture of 10.04 mm and a total horizontal aperture of 22.4 mm at the position of the scraper, i.e. in the straight sections. The lifetime in MAX II at the measurement with 180mA of stored beam at full energy, 1.5GeV, was 23.8h. The 23.8h of lifetime is the total lifetime which is determined by the following lifetime limiting effects: Touschek effect 37 h, quantum effect >>100 h, elastic scattering on the residual gas 134 h, and inelastic scattering on the residual gas 132 h. It has shown possible to inject into and ramp the MAX II storage ring with a total vertical aperture in the straight sections as small as 9.34 mm. The measurements have shown that it is possible to install an insertion device in MAX II with a 10mm aperture without decreasing the beam lifetime, provided that the insertion devices do not deteriorate the vacuum situation. The gas mixture of the residual gas in the MAX II storage ring at operation has been measured and the absolute gas pressure is given by the results from the scraper measurements. In MAX II, as in most accelerators, the residual gas is dominated by hydrogen. The residual gas pressure in MAX II with 180 mA of stored beam at 1.5 GeV was 5.24 x 10(-9) Torr and it consists of 96.5% H-2, 1.1% H2O, 1.8% CO, and 0.6% CO2. (C) 2003 Elsevier B.V. All rights reserved.},
  author       = {Wallén, Erik},
  issn         = {0167-5087},
  keyword      = {Touschek effect,aperture,acceptance,scattering,accelerator vacuum,beam lifetime},
  language     = {eng},
  number       = {3},
  pages        = {487--495},
  publisher    = {Elsevier},
  series       = {Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment},
  title        = {Aperture and lifetime measurements with moveable scrapers at MAX II},
  url          = {http://dx.doi.org/10.1016/S0168-9002(03)01650-4},
  volume       = {508},
  year         = {2003},
}