progress report of the glast acd beam test at cern (backsplash study) simulation and analysis...
DESCRIPTION
Nomenclature of ACD tile numbering There were 8 ACD tiles in the Beam Test. Here, the leftmost tile seen from Calorimeter is called “1 st ” and the rightmost one is called “8th”. Calorimeter ACD tiles Beam “1 st ” tile “8 th ” tileTRANSCRIPT
Progress report of the GLAST ACD Beam Test at CERN (Backsplash study) simulation and analysis
Tsunefumi Mizuno, Hirofumi Mizushima (Hiroshima Univ.) and
Tuneyoshi Kamae (SLAC)October 1st, 2002
•Detector Geometry/ACD tile numbering: pp.2-3•350GeVProton Calibration and simulation: pp.4-6•Real Data for 200GeV/50GeV e-:pp.7-11•Comparison between data and simulation: pp.12-15•Effect of the gap: pp.16-18•Summary: p.19
Detector Geometry
Veto Scint20cm x 20cm x 1 cmwith a hole (1cm diameter)
Trigger Scint1cm x 1cm x 1cm
Absorber (Pb)20cm x 20cm x 1 cmwith a hole (1cm diameter)
ACD54cm x 24cm x 1cm
Calorimeter Absorber20cm x 20cmthickness and material is adjustable
Calorimeter Gap20cm x 20cmthickness and material is adjustable
45cm
•Note: So far, we have been using G4 simulation program developed before the Beam Test. Detector Geometry (shown above) is not the same as, but similar to, that of experiment.
47cm
1cm
53cmBeam
Nomenclature of ACD tile numbering
• There were 8 ACD tiles in the Beam Test. Here, the leftmost tile seen from Calorimeter is called “1st” and the rightmost one is called “8th”.
Calorimeter
ACD tiles
Beam
“1st” tile“8th” tile
Proton (350GeV) Calibration (1)
“1st” tile (run09)Peak~1220Pedestal~149
“2nd” tile (run07)Peak~690Pedestal~147
“3rd” tile (run06)Peak~1180Pedestal~146
“4th” tile (run05)Peak~1150Pedestal~144
Proton (350GeV) Calibration (2)
“5th” tile (run04)Peak~1090Pedestal~164
“6th” tile (run03)Peak~1630Pedestal~153
“7th” tile (run02)Peak~730Pedestal~158
“8th” tile (run01)Peak~1250Pedestal~141
Energy deposition of 350 GeV Proton
• We assume that the peak position for 350 GeV proton corresponds to 1.7 MeV.
G4 Simulation with 350 GeV Proton
Real data for 200 GeV e- (1)• data: run45 (2inch Pb without gap)• background: run11
“1st” tile
“2nd” tile
“3rd” tile
“4th” tile
data
background
Real data for 200 GeV e- (2)
“5th” tile
“6th” tile
“7th” tile
data
background
• data: run45 (2inch Pb without gap)• background: run11
•Note: In this report, we just subtract background run histogram (blue) from backsplash run one (black).
Real data for 200 GeV e- (3)
Calorimeter
ACD tiles
Beam
“1st” tile“8th” tile
•backsplash level differs by a factor of ~2 between tiles
• data: run45 (2inch Pb without gap)• background: run11
Real data for 50 GeV e- (1)• data: run47 (2inch Pb without gap)• background: run11
“1st” tile
“2nd” tile
“3rd” tile
“4th” tile
data
background
Real data for 50 GeV e- (2)
“5th” tile
“6th” tile
“7th” tile
data
background
• data: run47 (2inch Pb without gap)• background: run11
•Note: In this report, we just subtract background run (blue histogram) from backsplash run (black histogram).
Comparison between data and simulation: 200 GeV e- (1)
“1st” tile
simulationdata
“2nd” tile
“3rd” tile
“4th” tile
•Note1: Statistical errors for simulation are similar to those of real data, but we do not show them for clarity.•Note2: In blue histograms (simulation), we do not take scintillator response into account.
Comparison between data and simulaiton: 200 GeV e- (2)
“5th” tile
simulationdata
“6th” tile
“7th” tile
•Simulation well predicts backsplash data for 200 GeV e-.
Comparison between data and simulation: 50 GeV e- (1)
“1st” tile
simulationdata
“2nd” tile
“3rd” tile
“4th” tile
•Note1: Statistical errors for simulation are similar to those of real data, but we do not show them for clarity.•Note2: In blue histograms (simulation), we do not take scintillator response into account.
Comparison between data and simulaiton: 200 GeV e- (2)
“5th” tilesimulationdata
“6th” tile
“7th” tile
•Simulation well predicts backsplash data for 50 GeV e-. To solve remaining difference, we may need to improve background subtraction and take response of scintillators into account.
Effect of the gap (1)
•Calorimeter without gap•(1inch Pb)x4
ACD tiles
Beam(50GeV/200GeV e-)
•Calorimeter with gap •(1inch Pb and air gap)x4
ACD tiles
Beam (50GeV/200GeV e-)
•Calorimeter with gap was used for some data and this might affect the backsplash as illustrated below. To estimate this effect, we run simulation.
Excess in backsplash
Effect of the gap (2): 200GeV e-
“1st” tile
“4th” tile
“7th” tilewith gap
without gap
•Gap might affect the backsplash of the “1st” (outermost) tile by a factor of 2 for 200GeV e-. The effect could be negligible for the inner tiles.
Effect of the gap (3): 50GeV e-
“1st” tile
“4th” tile
“7th” tilewith gap
without gap
•Gap might affect the backsplash of the “1st” (outermost) tile by a factor of 1-2 for 50GeV e-. The effect could be negligible for the inner tiles.
Summary•We analyzed 50GeV and 200GeV e- data (2inch Pb without gap) and compared them with simulation predictions.•The simulation reproduces the data well.•The effect of the gap of calorimeter might be up to by a factor of 2 for the outermost tile, but could be negligible for inner ones.
•We will update simulator geometry.•We may need to improve background subtraction and take scintillator response into account.•We will analyze/simulate data with calorimeter gap.