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Ludewig, H.

Paper Title Page
TH5RFP017 Grad-Level Radiation Damage of SiO2 Detectors 3479
 
  • N. Simos, G. Atoian, H. Ludewig, J.G. O'Conor, S.N. White
    BNL, Upton, Long Island, New York
  • N.V. Mokhov
    Fermilab, Batavia
  
 

Funding: Work performed under the auspices of the US Department of Energy


SiO2 quartz fibers of the LHC ATLAS 0-degree calorimeter (ZDC) anticipated to experience integrated doses of a few Grad at their closest position were exposed to 200 MeV protons and neutrons at the BNL Linac. Specifically, 1mm- and 2mm- diameter quartz (GE 124) rods were exposed to direct 200 MeV protons during the first phase of exposure leading to peak integrated dose of ~28 Grad. Exposure to a primarily neutron flux of 1mm-diameter SiO2 fibers was also achieved with a special neutron source arrangement. In a post-irradiation analysis the quartz fiber transmittance was evaluated as a function of the absorbed dose. Dramatic degradation of the transmittance property was observed with increased radiation damage. In addition, detailed evaluation of the fibers under the microscope revealed interesting micro-structural damage features and irradiation-induced defects. This paper presents the results of the irradiation damage study.

  
TH5RFP018 Effects of High Proton Fluences on CZT Detectors 3482
 
  • N. Simos, A. Aronson, A.E. Bolotnikov, G.S. Camarda, C. Copeland, R. James, H. Ludewig
    BNL, Upton, Long Island, New York
  
 

The effects of high fluences of energetic charged particles on CdZnTe detectors have been studied and are reported in this paper. Specifically, 200 MeV protons of the Brookhaven National Laboratory LINAC were used to bombard a set of CdZnTe detector crystals to fluences as high as 2.6x1016 protons/cm2. Following exposure a set of past-irradiation analyses were conducted to quantify the effects. These include (a) gamma-ray spectra analysis using a high-purity germanium detector in an effort to assess both the peak position shifting as a function of fluence and the spectral content, (a) resistivity and leakage current measurements, and (c) manifestation of radiation damage in the crystal microstructure. In addition, and based on the irradiation parameters used, a numerical prediction model was formulated aiming to benchmark the observed isotopes.