Omar Tibolla ISAPP Belgirate Italy 30 June 9

Omar Tibolla. ISAPP. Belgirate (Italy) 30 June - 9 July 2005 Gamma-ray Large Area Space Telescope -France -Germany -Italy -Japan -Sweden -USA Energy Range 10 ke. V-300 Ge. V. GLAST : - An imaging gamma-ray telescope (LAT) - A second instrument for the study of Gamma Ray Bursts (GBM).

Omar Tibolla. ISAPP. Belgirate (Italy) 30 June - 9 July 2005 The main instrument of GLAST is the Large Area Telescope (LAT): a pair conversion telescope: Anticoincidence Shield (ACD) made of plastic scintillator (Bicron-408) sensitive to charged particles; ACD is segmented to avoid self veto from Calorimeter backsplash and also for micrometeorites. ACD contains 16 towers and each tower is divided in two parts: TRACKER -the TRACKER (TKR): 18 layers in each tower -Tungsten converters (1. 08 χ0 : 78% prob) -2 orthogonal SSD planes of silicon microstrip sensors for detecting the electromagnetic shower -a CALORIMETER (CAL) of Cs. I crystals dopped by Tl; so the energy deposited by the EM shower is converted in light signal. CAL is characterized by fast decaying fluorescent light (~ns) and a long decaying afterglow (~ms). ANTICOINCIDENCE SHIELD CALORIMETER

Omar Tibolla. ISAPP. Belgirate (Italy) 30 June - 9 July 2005 LAT Specifications and Performance Compared with EGRET Quantity EGRET LAT (Minimim Spec. ) Energy Range 20 Me. V - 30 Ge. V 20 Me. V - 300 Ge. V Peak Effective Area (after background rejection) 1500 cm² > 8000 cm² Field of View 0. 5 sr > 2 sr Angular Resolution 5. 8° (100 Me. V) < 3. 5° (100 Me. V) < 0. 15° (>10 Ge. V) Energy Resolution 10% < 10% Deadtime per Event 100 ms < 100 μs Source Location Determination 15' < 0. 5' Point Source Sensitivity ~ 10 -7 cm-2 s-1 < 6 x 10 -9 cm-2 s-1

Omar Tibolla. ISAPP. Belgirate (Italy) 30 June - 9 July 2005 The Glast Burst Monitor (GBM) will include two sets of detectors: -12 sodium iodide (Na. I) scintillators -2 cylindrical bismuth germanate (BGO) scintillators The Na. I detectors are sensitive in the lower end of the energy range, from a few ke. V to about 1 Me. V and provide burst triggers and locations. The BGO detectors cover the energy range ~150 ke. V to ~ 30 Me. V, providing a good overlap with the Na. I at the lower end and with the LAT at the higher end. Schematic layout of the 12 Na. I and two BGO detectors on the GLAST spacecraft

Omar Tibolla. ISAPP. Belgirate (Italy) 30 June - 9 July 2005 GBM Specifications and Performance Compared with BATSE Quantity BATSE Energy Range 25 ke. V - 10 Me. V < 10 ke. V - > 25 Me. V Field of View 4π sr all sky not occulted by the Earth Energy Resolution < 10% Deadtime per Event GBM (Minimum Spec. ) < 15 μs Burst Sensitivity 0. 2 cm-2 s-1 < 0. 5 cm-2 s-1 GRB Alert Location ~ 25° < 15° GRB Final Location 1. 7° < 1. 5°

Omar Tibolla. ISAPP. Belgirate (Italy) 30 June - 9 July 2005 GAMMA-RAY BURSTS PULSARS Scientific purposes EXTRAGALACTIC BACKGROUND LIGHT And other extremely important features are the COMPLEMENTARITY WITH GROUND-BASED GAMMARAY TELESCOPES and that study the Universe COSMIC RAYS AND NEWGLAST PARTICLEwill PHYSICS INTERSTELLAR EMISSION REGIONS OF EM SPECTRUM. in UNEXPLORED UNIDENTIFIED EGRET SOURCES SOLAR FLARES AGN/BLAZARS

Omar Tibolla. ISAPP. Belgirate (Italy) 30 June - 9 July 2005 Background rejection with Classification Trees using R. -Signal file (ag-v 3 r 3 p 7 -merituple-prune 20031218 -fulltup. root) 722594 γ (power law, isotropic 4 ) -27 BKG files (ntuple_prune*. root) 5551326 events : p, e- , e + , albedo γ A day of “real” data (part of Data Challenge 1). Before bkg rejection with R CT was made in a single step: 0 signal I tried to do it in 2 steps: 1 bkg 1º: separate g from charged particles. 2º: separate with the same method signal g and albedo g 0 charged particle 1 γ 2 γ sign 3 γ albedo

Omar Tibolla. ISAPP. Belgirate (Italy) 30 June - 9 July 2005 Conclusions -Big improvements using matrix of costs, expecially in high energy bins. -Problems with second steps.

Omar Tibolla. ISAPP. Belgirate (Italy) 30 June - 9 July 2005 Conclusions (2)