Transcript ppt
Gamma-ray Large Area Space Telescope PDU Voltage Noise Dependence (Very Preliminary) Claudia Cecchi Stefano Germani Monica Pepe INFN Perugia Instrument Analysis Meeting April 21, 2006 GLAST LAT Project IA Meeting, April 21, 2006 Data Files We used data from the following runs: 27V-supply • 077002818 36-sec cosmic with 5 KHz fixed f external trigger • 077002819 36-sec cosmic with 6.5 KHz fixed f external trigger • 077002820 36-sec cosmic with 1 KHz random f external trigger • 077002821 36-sec cosmic with 3KHz random f external trigger • 077002822 36-sec cosmic with 5KHz random f external trigger • 077002823 36-sec cosmic with 5KHz random f external trigger 29V-supply • 077002837 36-sec cosmic with 5 KHz random f external trigger • 077002838 36-sec cosmic with 10 KHz random f external trigger We used SVAC and Merit variables !!! C. Cecchi - S. Germani – M. Pepe 2 GLAST LAT Project IA Meeting, April 21, 2006 Event Selection (Tracker Study) We want to select only noisy events therefore we ask for: • External Trigger Only – GemConditionsWord == 128 • No reconstructed Tracks – TkrNumTracks == 0 • No Energy in the Cal – CalEnergyRaw == 0 • No ACD Hits – AcdTileCount == 0 && AcdRibbonCOunt == 0 Then we compute the fraction of noisy events which have Hit Strips: Tower Occupancy: TkrTotalHits[tower] >0 Layer Occupancy: TkrTotalHits[tower][layer][view] >0 C. Cecchi - S. Germani – M. Pepe 3 GLAST LAT Project IA Meeting, April 21, 2006 Noisy Events /EventSelected 27V Supply 12 13 14 15 8 9 10 11 4 5 6 7 0 1 2 3 C. Cecchi - S. Germani – M. Pepe 4 GLAST LAT Project IA Meeting, April 21, 2006 Noisy Events /EventSelected 29V Supply 12 13 14 15 8 9 10 11 4 5 6 7 0 1 2 3 C. Cecchi - S. Germani – M. Pepe 5 Noisy Events /EventSelected GLAST LAT Project 27V – 29V Comparison IA Meeting, April 21, 2006 12 13 14 15 8 9 10 11 4 5 6 7 0 1 2 3 C. Cecchi - S. Germani – M. Pepe 6 GLAST LAT Project IA Meeting, April 21, 2006 Noisy Events /EventSelected 27V–29V Comparison (Zoom) C. Cecchi - S. Germani – M. Pepe 7 GLAST LAT Project IA Meeting, April 21, 2006 Noisy Events /EventSelected Layer Structure Tower 1 (Typical) C. Cecchi - S. Germani – M. Pepe 8 GLAST LAT Project IA Meeting, April 21, 2006 Noisy Events /EventSelected Layer Structure Tower 4 One Layer with High Occupancy (Not All Runs) C. Cecchi - S. Germani – M. Pepe 9 GLAST LAT Project IA Meeting, April 21, 2006 Noisy Events /EventSelected Layer Structure Tower 5 One Layer with High Occupancy C. Cecchi - S. Germani – M. Pepe 10 GLAST LAT Project IA Meeting, April 21, 2006 Noisy Events /EventSelected Layer Structure Tower 13 Two Layers with High Occupancy C. Cecchi - S. Germani – M. Pepe 11 GLAST LAT Project IA Meeting, April 21, 2006 Conclusions • Tracker – No Noise dependence from PDU Voltage (Up to Now) – We need to understand better • The Layers structures • The differences among different runs and run configurations – We may need some improvements to the Event Selection – We could change noise definition counting the number of hit strips in noisy events • CAL noise analysis – To Be Done C. Cecchi - S. Germani – M. Pepe 12