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Title: The nonlinear light output of NaI(Tl) detectors in the Modular Total Absorption Spectrometer

New detector array, the Modular Total Absorption Spectrometer (MTAS),was commissioned at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Lab(ORNL).Total absorption gamma spectra measured with MTAS are expected to improve beta-feeding patterns and beta strength functions in fission products.MTAS is constructed out of hexagonal NaI(Tl) detectors with a unique central module surrounded by 18 identical crystals assembled in three rings. The total NaI(Tl) mass of MTAS is over1000 kg.The response of the central and other 18 MTAS modules to -radiation was simulated using the GEANT4 tool kit modified to analyze the nonlinear light output of NaI(Tl).A detailed description oftheGEANT4modifications madeisdiscussed.SimulatedenergyresolutionofMTAS modules is found to agree well with the measurements for single transitions of 662keV (137Cs) with 8.2% full width half maximum (FWHM),835keV (54Mn) with FWHM of 7.5% FWHM, and 1115keV (65Zn) with FWHM of 6.5%.Simulations of single and multiple -rays from 60Co are also discussed.
 [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [5] ;  [5]
  1. Louisiana State Univ., Baton Rouge, LA (United States)
  2. Univ. of Warsaw (Poland)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Warsaw (Poland); Oak Ridge Associated Univ., Oak Ridge, TN (United States)
  5. Univ. of Tennessee, Knoxville, TN (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725; FG02-96ER40978
Accepted Manuscript
Journal Name:
Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment
Additional Journal Information:
Journal Volume: 788; Journal ID: ISSN 0168-9002
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Holifield Radioactive Ion Beam Facility (HRIBF)
Sponsoring Org:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
Country of Publication:
United States
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; Beta decay; Total; absorption spectrometry; NaI(Tl); Simulation; MTAS
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1247389