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The BRAN luminosity detectors for the LHC

Matis, H. S.; Placidi, M.; Ratti, A.; Turner, W. C.; Bravin, E. and Miyamoto, R. LU (2017) In Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 848. p.114-126
Abstract

This paper describes the several phases which led, from the conceptual design, prototyping, construction and tests with beam, to the installation and operation of the BRAN (Beam RAte of Neutrals) relative luminosity monitors for the LHC. The detectors have been operating since 2009 to contribute, optimize and maintain the accelerator performance in the two high luminosity interaction regions (IR), the IR1 (ATLAS) and the IR5 (CMS). The devices are gas ionization chambers installed inside a neutral particle absorber 140 m away from the Interaction Points in IR1 and IR5 and monitor the energy deposited by electromagnetic showers produced by high-energy neutral particles from the collisions. The detectors have the capability to resolve the... (More)

This paper describes the several phases which led, from the conceptual design, prototyping, construction and tests with beam, to the installation and operation of the BRAN (Beam RAte of Neutrals) relative luminosity monitors for the LHC. The detectors have been operating since 2009 to contribute, optimize and maintain the accelerator performance in the two high luminosity interaction regions (IR), the IR1 (ATLAS) and the IR5 (CMS). The devices are gas ionization chambers installed inside a neutral particle absorber 140 m away from the Interaction Points in IR1 and IR5 and monitor the energy deposited by electromagnetic showers produced by high-energy neutral particles from the collisions. The detectors have the capability to resolve the bunch-by-bunch luminosity at the 40 MHz bunch rate, as well as to survive the extreme level of radiation during the nominal LHC operation. The devices have operated since the early commissioning phase of the accelerator over a broad range of luminosities reaching 1.4×1034 cm−2 s−1 with a peak pileup of 45 events per bunch crossing. Even though the nominal design luminosity of the LHC has been exceeded, the BRAN is operating well. After describing how the BRAN can be used to monitor the luminosity of the collider, we discuss the technical choices that led to its construction and the different tests performed prior to the installation in two IRs of the LHC. Performance simulations are presented together with operational results obtained during p-p operations, including runs at 40 MHz bunch rate, Pb-Pb operations and p-Pb operations.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Fast Ionization Chamber, Gas Detector, Ionization Chamber, LHC, Luminosity Detector
in
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
volume
848
pages
13 pages
publisher
Elsevier
external identifiers
  • scopus:85008400472
ISSN
0168-9002
DOI
10.1016/j.nima.2016.12.019
language
English
LU publication?
yes
id
d4d9b2ec-296a-4eb6-9811-4be5f64ac37d
date added to LUP
2017-03-09 12:58:54
date last changed
2018-01-07 11:54:46
@article{d4d9b2ec-296a-4eb6-9811-4be5f64ac37d,
  abstract     = {<p>This paper describes the several phases which led, from the conceptual design, prototyping, construction and tests with beam, to the installation and operation of the BRAN (Beam RAte of Neutrals) relative luminosity monitors for the LHC. The detectors have been operating since 2009 to contribute, optimize and maintain the accelerator performance in the two high luminosity interaction regions (IR), the IR1 (ATLAS) and the IR5 (CMS). The devices are gas ionization chambers installed inside a neutral particle absorber 140 m away from the Interaction Points in IR1 and IR5 and monitor the energy deposited by electromagnetic showers produced by high-energy neutral particles from the collisions. The detectors have the capability to resolve the bunch-by-bunch luminosity at the 40 MHz bunch rate, as well as to survive the extreme level of radiation during the nominal LHC operation. The devices have operated since the early commissioning phase of the accelerator over a broad range of luminosities reaching 1.4×10<sup>34</sup> cm<sup>−2</sup> s<sup>−1</sup> with a peak pileup of 45 events per bunch crossing. Even though the nominal design luminosity of the LHC has been exceeded, the BRAN is operating well. After describing how the BRAN can be used to monitor the luminosity of the collider, we discuss the technical choices that led to its construction and the different tests performed prior to the installation in two IRs of the LHC. Performance simulations are presented together with operational results obtained during p-p operations, including runs at 40 MHz bunch rate, Pb-Pb operations and p-Pb operations.</p>},
  author       = {Matis, H. S. and Placidi, M. and Ratti, A. and Turner, W. C. and Bravin, E. and Miyamoto, R.},
  issn         = {0168-9002},
  keyword      = {Fast Ionization Chamber,Gas Detector,Ionization Chamber,LHC,Luminosity Detector},
  language     = {eng},
  month        = {03},
  pages        = {114--126},
  publisher    = {Elsevier},
  series       = {Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
  title        = {The BRAN luminosity detectors for the LHC},
  url          = {http://dx.doi.org/10.1016/j.nima.2016.12.019},
  volume       = {848},
  year         = {2017},
}