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Title: Detector for measuring the π+ → e+v branching fraction

The PIENU experiment at TRIUMF is aimed at a measurement of the branching ratio Re/u = Γ((π+ → e+ve) + (π+ → e+veγ))/Γ((π+ → μ+vμ) + (π+ → μ+vμγ)) with precision < 0.1%. Incident pions, delivered at the rate of 60 kHz with momentum 75 MeV/c, were degraded and stopped in a plastic scintillator target. Pions and their decay product positrons were detected with plastic scintillators and tracked with multiwire proportional chambers and silicon strip detectors. The energies of the positrons were measured in a spectrometer consisting of a large NaI(Tℓ) crystal surrounded by an array of pure CsI crystals. This paper provides a description of the PIENU experimental apparatus and its performance in pursuit of Re/u
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [5] ;  [4] ;  [6] ;  [6] ;  [7] ;  [8] ;  [2] ;  [2] ;  [9] ;  [6] ;  [9] ;  [4] ;  [6] ;  [2] ;  [6] more »;  [6] ;  [6] ;  [4] ;  [8] ;  [6] ;  [2] ;  [2] « less
  1. Universidad Nacional Autonoma de Mexico (Mexico). Inst. de Ciencias Nucleares
  2. Osaka Univ. (Japan). Graduate School of Science
  3. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
  4. Univ. of British Columbia, Vancouver, BC (Canada). Dept. of Physics and Astronomy
  5. Arizona State Univ., Tempe, AZ (United States)
  6. TRIUMF, Vancouver, BC (Canada)
  7. Univ. of Northern British Columbia, Prince George, BC (Canada)
  8. National Lab. for High Energy Physics (KEK), Tsukuba (Japan)
  9. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
OSTI Identifier:
1210167
Report Number(s):
BNL--108201-2015-JA
Journal ID: ISSN 0168-9002; R&D Project: PO-022; KA2201020; TRN: US1600721
Grant/Contract Number:
18540274; 21340059; 24224006
Type:
Accepted Manuscript
Journal Name:
Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment
Additional Journal Information:
Journal Volume: 791; Journal Issue: C; Journal ID: ISSN 0168-9002
Publisher:
Elsevier
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS CSI; scintillation detectors; pion decay