a design study for a cobra upgrade to - Institut für Kern- und ...

More documents

Recommendations

Info

54 5 Scintillator upgrade event ID track ID particle Ei Edep x process step 6 1 gamma 500.00 0.00 31.83 compt 10 6 1 gamma 202.62 0.00 31.55 compt 10 6 1 gamma 131.54 0.00 15.92 compt 10 6 1 gamma 130.54 0.00 0.00 trans 10 6 4 e- 0.991 0.99 15.92 eIoni 10 6 3 e- 71.09 71.09 31.55 eIoni 10 6 2 e- 297.38 152.73 31.93 eBrem 10 6 2 e- 108.59 108.59 31.90 eIoni 10 6 5 gamma 36.06 1.56 25.24 phot 10 6 6 e- 34.49 34.49 25.24 eIoni 10 Table 5.1: Detailed output from simulation ”ScintBlock” of one 500 keV photon in NaI, whereas y and z values of interaction points are missing in this list. other) on a scintillator block with 1 m lateral length and 21 different width, ranging from 1 mm to 1 m was examined. Thereby photons with 10 different energies from 200 to 2000 keV were initialised. Due to the arguments from chapter 4.1.3—“Scintillating materials” only NaI, CsI, BGO and CWO crystal were considered. For every data file, the total amount of interacting photons and the fullenergy events were counted. RESULTS In table 5.2 the peak and total absorption efficiency for scintillators of different width for different photon energies, which was obtained with this simulation, is listed. The peak absorption efficiency is the efficiency for absorbing the full energy of the incident photon and the total absorption efficiency is the total efficiency of the initial photon for interacting with the scintillator material. This was mapped for incident 1200 keV photons, as can be seen in figure 5.1. The total and peak efficiencies of the four scintillators are shown in A—“FIRST APPENDIX” in figure B.1 - B.7. NaI has the smallest density of these scintillators and correspondingly the smallest absorption efficiency. CWO has higher density but a smaller effective atomic number Zeff than BGO. This leads to different total and peak efficiencies for BGO and CWO. The efficiencies depend on the density and atomic number of the absorber material and the energy of the initial photon.
5.1 Monte Carlo studies for the upgrade design 55 Figure 5.1: Ratio of 1200 keV photons, depositing full energy in the scintillator to total simulated photons, after various width of NaI, CsI, BGO and CWO 5.1.2 Price research For a price estimation of the scintillator upgrade, quotations from Scionix [45] and SaintGobain [36] were solicited from EKM, the German distributor for Scionix and GCTechnology Messgeräte Vertriebs GmbH, the German distributor for SaintGobain. The prices are listed in table 5.3. The analysis, discussed in the previous section, investigated the absorption efficiencies for different scintillators. An efficiency for absorbing the full energy of 90 % of the incident photons requires 23.2 cm of NaI:Tl, 18.6 cm of CsI:Tl, 9.0 cm of BGO and 9.2 cm of CWO. Due to the high cost for such big scintillator crystals, smaller detection efficiencies are inevitable. In addition to the costs of the scintillation detectors itself, it is necessary to acquire new shielding material. The provided space in the Faraday
Page 1 and 2:
A DESIGN STUDY FOR A COBRA UPGRADE
Page 3:
I hereby declare that I have create
Page 6 and 7:
vi Abstract
Page 8 and 9:
viii Überblick
Page 10 and 11:
x Contents 4.1.2 Scintillation proc
Page 12 and 13:
xii Contents
Page 14 and 15:
2 1 Introduction The CdZnTe detecto
Page 16 and 17: 4 2 Neutrino physics mass scales no
Page 18 and 19: 6 2 Neutrino physics Ground states
Page 20 and 21: 8 2 Neutrino physics mi: 〈mνe〉
Page 22 and 23: 10 2 Neutrino physics
Page 24 and 25: 12 3 The COBRA experiment CdZnTe (C
Page 26 and 27: 14 3 The COBRA experiment 1420:480:
Page 28 and 29: 16 3 The COBRA experiment Figure 3.
Page 30 and 31: 18 3 The COBRA experiment They are
Page 32 and 33: 20 3 The COBRA experiment Therefore
Page 34 and 35: 22 4 Scintillation detectors search
Page 36 and 37: 24 4 Scintillation detectors Figure
Page 38 and 39: 26 4 Scintillation detectors spectr
Page 40 and 41: 28 4 Scintillation detectors SCINTI
Page 42 and 43: 30 4 Scintillation detectors emissi
Page 44 and 45: 32 4 Scintillation detectors activa
Page 46 and 47: 34 4 Scintillation detectors descri
Page 50 and 51: 38 4 Scintillation detectors group
Page 56 and 57: 44 4 Scintillation detectors AVALAN
Page 60 and 61: 48 4 Scintillation detectors gap. T
Page 62 and 63: 50 4 Scintillation detectors photoc
Page 64 and 65: 52 5 Scintillator upgrade ergy phys
Page 68 and 69: 56 5 Scintillator upgrade Ephoton (
Page 70 and 71: 58 5 Scintillator upgrade back side
Page 72 and 73: 60 5 Scintillator upgrade three dif
Page 74 and 75: 62 5 Scintillator upgrade vice. The
Page 76 and 77: 64 5 Scintillator upgrade lecting e
Page 78 and 79: 66 5 Scintillator upgrade Figure 5.
Page 84 and 85: 72 5 Scintillator upgrade In 3.1 %
Page 86 and 87: 74 5 Scintillator upgrade were repo
Page 90 and 91: 78 5 Scintillator upgrade crystal p
Page 92 and 93: 80 5 Scintillator upgrade and gamma
Page 94 and 95: 82 5 Scintillator upgrade Backgroun
Page 96 and 97: 84 5 Scintillator upgrade source of
Page 98 and 99: 86 6 Summary and future work dimens
Page 100 and 101: 88 A FIRST APPENDIX Scintillator De
Page 102 and 103: 90 A FIRST APPENDIX A.2 Reports abo
Page 104 and 105: 92 A FIRST APPENDIX trons than a st
Page 106 and 107: 94 B SECOND APPENDIX Figure B.1: Am
Page 108 and 109: 96 B SECOND APPENDIX Figure B.5: Am
Page 110 and 111: 98 B SECOND APPENDIX B.2 Geant4 Gea
Page 112 and 113: 100 B SECOND APPENDIX Cube, scint64
Page 114 and 115: 102 B SECOND APPENDIX
Page 116 and 117:
104 Bibliography [13] H. V. Klapdor
Page 118 and 119:
106 Bibliography [43] T. Y. Kim et
Page 120:
Typeset September 29, 2010
show all

a design study for a cobra upgrade to - Institut für Kern- und ...

Create successful ePaper yourself

Delete template?

Save as template?