Transcript ppt
LAT Instrument Analysis Meeting – July 14, 2006 GLAST LAT Project GLAST Large Area Telescope: Gamma-ray Large Area Space Telescope TKR Trending @ NRL Hiro Tajima (SLAC) TKR [email protected] 650-926-3035 Hiro Tajima, TKR Trending @ NRL 1 GLAST LAT Project LAT Instrument Analysis Meeting – July 14, 2006 From Previous Efficiency Trending • • Some layers (Bay 3 Y6, Bay 5 X14, Bay 5 Y12, Bay 6 Y3, Bay 7 Y16, Bay 8 X11, Bay 8 X7) showed non-negligible efficiency drop. – No apparent cause (dead, disconnected or hot strips, noise flare). Add more runs between 77005000 and 77006000. – Lower minimum duration limit to 500 seconds. Hiro Tajima, TKR Trending @ NRL 2 LAT Instrument Analysis Meeting – July 14, 2006 GLAST LAT Project When efficiency drop started? • Efficiency drop started between run# 77005444 (5/29) and 77005454 (6/1). – Common cause? – Vibe Z axis performed on 5/31. • Michael Kuss found no issue with TKR tower internal alignment. – No change in TKR related register values Bay 3 Y6 Bay 5 X14 Bay 5 Y12 Bay 6 Y3 Bay 7 Y16 Bay 8 X11 Bay 8 X7 Hiro Tajima, TKR Trending @ NRL 3 LAT Instrument Analysis Meeting – July 14, 2006 GLAST LAT Project More Efficiency Loss • More layers with similar efficiency loss – Total 39 layers were affected. – Some layers fully recovered. – Some layers recovered half way. – Some layers no receovery. Hiro Tajima, TKR Trending @ NRL 4 LAT Instrument Analysis Meeting – July 14, 2006 GLAST LAT Project TKR Muon Peak Trending • Charge scale: muon peak normalized to expected MIP peak. – Requires 4 hours of muon data. • Mean value of muon peak has been drifting since last TOT calibration performed on 4/19. • Spread of muon peak is also increasing. • Requested new TOT calibration. 1.18 0.12 mean 1.16 RMS FMA FM2 FM14 FM15 FMB FM1 FM12 FM13 FM5 FM3 FM7 FM9 FM6 FM4 FM10 FM11 Charge scale mean 1.14 1.12 1.1 1.08 1.06 Charge scale RMS 0.1 FMA FM2 FM14 FM15 FMB FM1 FM12 FM13 FM5 FM3 FM7 FM9 FM6 FM4 FM10 FM11 0.08 0.06 0.04 0.02 1.04 1.02 0 60114 60418 60426 Timestamp 60508 60628 Hiro Tajima, TKR Trending @ NRL 60114 60418 60426 Timestamp 5 60508 60628