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Choppers to optimise the repetition rate multiplication technique on a direct geometry neutron chopper spectrometer

Vickery, A. and Deen, Pascale LU (2014) In Review of Scientific Instruments 85(11).
Abstract
In recent years the use of repetition rate multiplication (RRM) on direct geometry neutron spectrometers has been established and is the common mode of operation on a growing number of instruments. However, the chopper configurations are not ideally optimised for RRM with a resultant 100 fold flux difference across a broad wavelength band. This paper presents chopper configurations that will produce a relative constant (RC) energy resolution and a relative variable (RV) energy resolution for optimised use of RRM. The RC configuration provides an almost uniform Delta E/E for all incident wavelengths and enables an efficient use of time as the entire dynamic range is probed with equivalent statistics, ideal for single shot measurements of... (More)
In recent years the use of repetition rate multiplication (RRM) on direct geometry neutron spectrometers has been established and is the common mode of operation on a growing number of instruments. However, the chopper configurations are not ideally optimised for RRM with a resultant 100 fold flux difference across a broad wavelength band. This paper presents chopper configurations that will produce a relative constant (RC) energy resolution and a relative variable (RV) energy resolution for optimised use of RRM. The RC configuration provides an almost uniform Delta E/E for all incident wavelengths and enables an efficient use of time as the entire dynamic range is probed with equivalent statistics, ideal for single shot measurements of transient phenomena. The RV energy configuration provides an almost uniform opening time at the sample for all incident wavelengths with three orders of magnitude in time resolution probed for a single European Spallation Source (ESS) period, which is ideal to probe complex relaxational behaviour. These two chopper configurations have been simulated for the Versatile Optimal Resolution direct geometry spectrometer, VOR, that will be built at ESS. (c) 2014 AIP Publishing LLC. (Less)
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organization
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type
Contribution to journal
publication status
published
subject
in
Review of Scientific Instruments
volume
85
issue
11
publisher
American Institute of Physics
external identifiers
  • wos:000345646000294
  • scopus:84922454013
ISSN
1089-7623
DOI
10.1063/1.4900958
language
English
LU publication?
yes
id
63cb9df8-1577-4ab6-ad6d-c4417421aaea (old id 4979640)
date added to LUP
2015-01-27 13:13:40
date last changed
2017-01-01 05:25:25
@article{63cb9df8-1577-4ab6-ad6d-c4417421aaea,
  abstract     = {In recent years the use of repetition rate multiplication (RRM) on direct geometry neutron spectrometers has been established and is the common mode of operation on a growing number of instruments. However, the chopper configurations are not ideally optimised for RRM with a resultant 100 fold flux difference across a broad wavelength band. This paper presents chopper configurations that will produce a relative constant (RC) energy resolution and a relative variable (RV) energy resolution for optimised use of RRM. The RC configuration provides an almost uniform Delta E/E for all incident wavelengths and enables an efficient use of time as the entire dynamic range is probed with equivalent statistics, ideal for single shot measurements of transient phenomena. The RV energy configuration provides an almost uniform opening time at the sample for all incident wavelengths with three orders of magnitude in time resolution probed for a single European Spallation Source (ESS) period, which is ideal to probe complex relaxational behaviour. These two chopper configurations have been simulated for the Versatile Optimal Resolution direct geometry spectrometer, VOR, that will be built at ESS. (c) 2014 AIP Publishing LLC.},
  articleno    = {115103},
  author       = {Vickery, A. and Deen, Pascale},
  issn         = {1089-7623},
  language     = {eng},
  number       = {11},
  publisher    = {American Institute of Physics},
  series       = {Review of Scientific Instruments},
  title        = {Choppers to optimise the repetition rate multiplication technique on a direct geometry neutron chopper spectrometer},
  url          = {http://dx.doi.org/10.1063/1.4900958},
  volume       = {85},
  year         = {2014},
}