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Diamond – Tungsten Calorimeter. LCAL-group : K. Afanasiev, V. Drugakov, E. Kouznetsova, W. Lohmann, A. Stahl. Workshop on Forward Calorimetry and Luminosity Measurement In the TESLA Detector 13-14 November 2002, DESY-Zeuthen. Location. Requirements.
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Diamond – Tungsten Calorimeter LCAL-group : K. Afanasiev, V. Drugakov, E. Kouznetsova, W. Lohmann, A. Stahl Workshop on Forward Calorimetry and Luminosity Measurement In the TESLA Detector 13-14 November 2002, DESY-Zeuthen
Location • Requirements • Detection and measurement of electrons and photons at small angles • Fast beam diagnostic • Improvement of the energy flow measurement in forward/backward direction • Shielding of the inner part of the detector
Beam-beam Background GUINEAPIG + BRAHMS ( for √s = 500 GeV ) : • Per bunchcrossing : • ~15000 e± hits • ~20 TeV of deposited energy • (R,f)-distribution of the deposited energy: High radiation resistivity is required Two options for calorimeter technology : • Heavy scintillator • Diamond-tungsten sandwich
CVD DIAMOND properties • Comparison to silicon :
CVD DIAMOND properties • Radiation hardness : www.desy.de/~ghodbane
Tungsten absorber • + Diamond sensor RM ~ 1 cm • Sandwich LCAL geometry • Z - Segmentation : Tungsten 3.5 mm Layer = Diamond 0.5 mm • (R,f) - Segmentation :
Sandwich LCAL background • Average energy deposited in “bad” cells: ~ 7 GeV • Dose expected for “bad” cells : ~10 MGy/year • 250 GeV e- + BG :
sensor PA/discr ADC reconstruction • Sandwich LCAL recognition • Algorithm : • “Suspected” cells : ECELL > 3 sBG • reasonable z-location • Requirement of longitudinal chain of such cells • Choice of a proper ADC :
Sandwich LCAL recognition • Efficiency vs radius :
Sandwich LCAL recognition • Energy resolution vs radius :
Sandwich LCAL recognition • Polar angle resolution vs radius :
Sandwich LCAL Recognition • Calibration : • Averaged energy resolution :
Sandwich LCAL Recognition • Averaged angular resolution :
CONCLUSIONS • Diamond/W LCAL following steps : • Real sensor test : to see mip-signal : ~1.5 fC VV50-3 • sandwich diamond-tungsten calorimeters seems to be a promising technology • high energetic e±, g can be detected with reasonable efficiency even near the beam pipe • energy and angular resolution for diamond-tungsten are good