Документ взят из кэша поисковой машины. Адрес оригинального документа : http://zebu.uoregon.edu/~uochep/talks/talks02/Frey-wsi.pdf Дата изменения: Thu Jan 23 21:57:02 2003 Дата индексирования: Tue Oct 2 10:50:28 2012 Кодировка: Поисковые слова: m 5

First Lo ok at W/Si Dynamic Range Requirement
Ray Frey, U. of Oregon

· Want to measure MIPs (400 keV/mm in Si) and dense EM showers due to 250 (500) GeV Bhabha e± · EM showers in W are dense: W only: Rm = X0(21.2MeV/Ec) = 9.1 mm · But is mo dified significantly by sampling layers: W/Si: Rm 9.1mm [1+ (Sigap)/(zW )] · for SD, zW = 2.5 mm; can trade off Rm E 1. EGS setup

2. Results

3. Conclusions
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EGS Setup

· Use the G. Lindstrom recommendations for Ecut in thin sampling layers. (Go o d accuracy with finite CPU time.)

· Reduced Ecut, Pcut in thin regions near the Si · Step size small (0.3%) everywhere
~6 X 0.5 mm 0.4 mm 0.5 mm >3X

W bulk

W thin 100 keV 100 keV

Si 100 keV 20 keV

W thin 100 keV 500 keV

W bulk 500 keV 1000 keV

e

Ecut = 500 keV Pcut = 500 keV

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· Fraction of total EDEP in 1cmв 1cm : (Ee = 100 GeV)

1. Broad shower max in depth 6.5 ± 1 X0 2. Fraction of energy in central 1cmв 1cm is indep endent of Ee Results not sensitive to these

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· EDEP fraction in center pixel as function of pixel size (mm):

need big pixel size reduction to change dynamic range requirement significantly

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· For this config. and 1cmв1 cm Si: 250 GeV Bhabha / MIP = (340MeV)/(0.16MeV) = 2.1 в 103 decrease in pixel area by 100 gives only 2-3 bits reduction result scales for max. energy 500 GeV · Current thinking is 3 linear 12-bit ranges (driven by resolution) See M. Breidenbach talk

· Now have co de to mo del full ECal stack interesting to compare with GEANT4 and GISMO

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