1. GLAST LAT Project LAT Instrument Analysis Meeting– Aug 29, 2005 Hiro Tajima, TKR Updates at SLAC 1 GLAST Large Area Telescope: TKR Updates at SLAC Hiro Tajima (SLAC) Johann Cohen-Tanugi (SLAC) TKR htajima@slac.stanford.edu 650-926-3035 Gamma-ray Large Area Space Telescope

2. GLAST LAT Project LAT Instrument Analysis Meeting– Aug 29, 2005 Hiro Tajima, TKR Updates at SLAC 2 OUTLINE End-toEnd TOT Calibrations –Summary of TOT calibration sequence. –Charge scale distribution for 8-tower data –Comparison between MC and data. TOT distribution Angle dependence of TOT peak Efficiency trending.

3. GLAST LAT Project LAT Instrument Analysis Meeting– Aug 29, 2005 Hiro Tajima, TKR Updates at SLAC 3 End-to-End TOT Calibration Summary TACK timing. –done. GTFE charge injection scale. –done. GTFE Threshold. –done. TOT gain parameter. –Correct thresholds were not used due to a bug in the TKR script Fixed before 8-tower tests. – Column and row number were swapped due to a bug in LATTE tower mapping. Fixed before 8-tower tests. TKR recon. –Wrong scale was used for “charge per MIP” parameter.

4. GLAST LAT Project LAT Instrument Analysis Meeting– Aug 29, 2005 Hiro Tajima, TKR Updates at SLAC 4 Charge Scale after TOT Calibrations Definition of charge scale. –Plot ratio 4.92/peak. (4.92 fC is expected for MIP) (should be 1.0 if calibration is correctly applied.) Before charge scale calibration 6-tower data (after charge scale calibration) Wrong “fC per MIP” parameter 8-tower data (after fixes) Tower row and column Numbers swapped for TOT gain parameter Johann

5. GLAST LAT Project LAT Instrument Analysis Meeting– Aug 29, 2005 Hiro Tajima, TKR Updates at SLAC 5 Data/MC Comparison: TOT Distribution Fit parameters for data and MC are very similar –Gaussian convolved Landau distribution function –Peak at 4.91 : 4.92 fC –Landau width at 0.375 : 0.344 –Gaussian sigma at 0.69 : 0.69 TOT charge (fC) MC Data TOT charge (fC) Johann

6. GLAST LAT Project LAT Instrument Analysis Meeting– Aug 29, 2005 Hiro Tajima, TKR Updates at SLAC 6 Angle Dependence of TOT Peak Incident angle dependence of TOT peak. MC before angle correction: 10% effect MC after angle correction: <1% effect cos  TOT peak (fC) MC cos  8-tower data after angle correction: ~1% residual effect DATA Johann

7. GLAST LAT Project LAT Instrument Analysis Meeting– Aug 29, 2005 Hiro Tajima, TKR Updates at SLAC 7 Tower Efficiency Trending Trend tower efficiency during I&T phase –All I&T data sets are analyzed by the latest TkrRecon. –FMB and FM1 shows consistent (but tiny) downward trend. 0.06% inefficiency corresponds to ONE strip. Johann

8. GLAST LAT Project LAT Instrument Analysis Meeting– Aug 29, 2005 Hiro Tajima, TKR Updates at SLAC 8 Conclusions Calibration procedure for TOT/threshold/charge scale is demonstrated end-to-end. –Improvement can be made for angle dependence of TOT peak in data. –TOT distributions in data and MC are very similar. Started tower efficiency trending. –No major drop of efficiency observed. –Tiny and consistent downward trend in FMB and FM1. Plan to trend more parameters. –# of bad channels, thresholds, TOT parameters…