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2 Introduction   MiniCal test-beam studies started at the beginning of March (till March 6 we only had 17 APD’s, then 33 APD’s)   A few days were.

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Presentation on theme: "2 Introduction   MiniCal test-beam studies started at the beginning of March (till March 6 we only had 17 APD’s, then 33 APD’s)   A few days were."— Presentation transcript:

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2 2 Introduction   MiniCal test-beam studies started at the beginning of March (till March 6 we only had 17 APD’s, then 33 APD’s)   A few days were necessary to get the system running  Adjust light output of LED fibers  Remove grounding problems (still see 50 Hz pickup)  Place fan inside black box to stabilize temperature   First data taking with Miland’s preamps (Cvach)   After a week started data taking with Gilitzki preamp  Calibration of 12 cassettes (3 tiles/APD, each center tile)  Long term stability studies with LED  Measure beam energies (1-6 GeV) for 3tile/APD, or  Vary APD gain 

3 The MiniCal Structure 97% of 6 GeV shower contained in 12 layers e + -beam   Fe-scintillator sandwich  12 (13) sci layers of 9 tiles each held in cassettes (~1.15X 0 or 0.12  per layer) 3 tiles/pixel (APD)  3 tiles/pixel (APD) (each center (each center tile/pixel) tile/pixel) 33 APD’s  33 APD’s 3/3/3/3/(1)  3/3/3/3/(1) tiles/cell tiles/cell 2 cm steel 0.5 cm active 0.1 cm Ø WLS fibers

4 4 Calibration Setup e+e+e+e+ 1-6 GeV x x x x x x x x x  Move cassettes out of Fe absorber out of Fe absorber  Steer beam at of each tile center of each tile center

5 5 MIP Calibration of APD   Use 3 GeV e + beam on single tile, no Fe absorber in front MIP MPV Gauss Landau   MIP MPV =Peak–pedestal   Fit with 1 Gaussian for pedestal, 1 Gaussian for MIP peak position & a Landau tail for sampling fluctuations   Pedestal determination may be uncertain by ±1 ADC channel  cause uncertainty in  linearity  and  /E #ADC

6 6 MIP Calibration of APDs   Obtain similar spectra with SiPM and APD   For comparison with SiPM & PM calibrations we also perform measurements with central tile of 13 layers read out individually  since we only have 33 APD’s we can only read out 4 sides and one corner Not readout 3 tiles/APD 1 tile/APD APD

7 7 Energy Sums for APD Readout   Sum up energies of 93 tiles (in MIP MPV s) for beam energies of 1-6 GeV 1 GeV 2 GeV 4 GeV 3 GeV 6 GeV 5 GeV #MIP MPV  Distributions look similar look similar as those for as those for PM readout PM readout

8 8 Energy Sums for APD Readout   Sum up energies of 93 tiles (in MIP MPV s) for beam energies of 1-6 GeV 1 GeV 2 GeV 4 GeV 3 GeV 6 GeV 5 GeV #MIP MPV Recent data

9 9 Energy Sums for PM Readout   5% systematic uncertainty Energy Sum 1 GeV2 GeV 4 GeV3 GeV 6 GeV5 GeV N MIP

10 10 Temperature Monitoring   Daily changes vary C and C open box   Anytime, box is opened T jumps occur  wait for >30 min before starting with measurements

11 11 LED Monitoring of APD’s 1 GeV 2 GeV 3 GeV 4 GeV 5GeV 6GeV   T variations in MiniCal are <1.4 0 C over 24h period   APD’s seem to be stable within ~1% over 1-2 h period

12 12 Linearity of Photo Detector Response   Very good agreement between PM, SiPM & MC   APD slope is somewhat larger (why ?)   Sum of energy deposited in all tiles calibrated in #MIP MPV  Systematic errors   2% homogeneity of Segment-calibration   2% reproducibility of calibration   ~2% beam energy spread

13 13 EM Energy Resolution   Fit re with 1GeV beam probably related to magnet hysteresis   Energy resolution   Have no sensitivity to small noise term   Limited sensitivity to constant term   Very good agreement between PM & SiPM   Simulation needs to include more effects: beam energy spread, material thickness fluctuations,

14 14 EM Energy Resolution   Use 1 GeV point in the fit  obtain similar results as with excluding point   APD results have no problems with 1 GeV point

15 15 EM Energy Resolution

16 16 EM Energy Resolution

17 17 LED Monitoring   Recent monitoring of LED between start of calibration and data taking   Temperature varied by C in ~5 h   Observe slight shift between 1 st calibration run and two energy runs   Need to apply temperature correction calibration 1 GeV 6 GeV


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