lcg meeting, may 14th 2003 v. daniel elvira1 g4 (oscar_1_4_0) validation of cms hcal v. daniel...
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LCG Meeting, May 14th 2003
V. Daniel Elvira 1
G4 (OSCAR_1_4_0) Validation of CMS HCal
V. Daniel Elvira
Fermilab
LCG Meeting, May 14th 2003
V. Daniel Elvira 2
General Description
• Simulate HCal test beam 2002 setup using OSCAR_1_4_0, physics list 1.8
•Includes beam line (trigger scint. tiles, wire chambers), ECal box, HB, HO, aluminium slab (representing magnet), iron (muon) layer
• Mimic the data analysis, including calibration from electrons (ECal) and pions (HB): study resolution, response (linearity), transverse shower profiles
•Compare with data measurements for G4 validation
LCG Meeting, May 14th 2003
V. Daniel Elvira 3
ECal 7x7 Crystal Matrix (movable)
2 HCal HB Modules
HO Panels
Aluminum Slab
HCal 2002 Test Beam
beam
Moving table
Small scale experiment to demonstrate that HCal works: 49 ECal crystals, 144 HB channels, 16 HO channels.
Over 100 Million
Events!
-: 225 GeV
e-: 20,30,50,100 GeV
-: 20,30,50,100,
300 GeV
LCG Meeting, May 14th 2003
V. Daniel Elvira 4
Based on 1-5,000 events onto the ()=(6,2) tower of the HB and crystal 25 of the ECal matrix
TB02 Simulation (OSCAR/G4 )
Crystal 25
LCG Meeting, May 14th 2003
V. Daniel Elvira 5
Angle view of the full TB02 detector
10 GeV electron
HB
ECalHO
Beam Line
HO
HB
ECal
Beam Line
TB02 Simulation (OSCAR/G4 )
100 GeV pion
LCG Meeting, May 14th 2003
V. Daniel Elvira 6
Ecorr= 122*EHB
5x5+1.05*EECal3x3
EHBscint EHB
scint+ 0.1* EHBscint MeV * Rand
EHBtower EHB
tower+ 262 MeV * RandLong. Non-uniformity
Electronic Noise
Calibration factors (already there in previous presentation)
EECaltower EECal
tower+ match* Rand (To match the measured electron resolution-much worse than M.C.)
•Add more energy points at 10, 25, 200, 250, 300 GeV (in addition to 20, 30, 50, 100, 150 GeV)• 5 times more statistics 10-30 GeV
Improved M.C. Simulation
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/E=30.9% (similar to the fit to ¾ of second peak by Jordan)
Data analysis: sources systematic errors:• muon (pion decay) & electrons (from scrapping?) backgrounds• calibration
Data Analysis
LCG Meeting, May 14th 2003
V. Daniel Elvira 8
From J.Damgov
Electron background
Muon background Background
subtracted muon peak
It should be possible to estimate background subtraction error by defining a band limited by an “aggressive” (bckgnd rejection) and a “conservative cut” (signal efficiency)
The resolution comes down from 31% to 26.7% !
Pion Signal
TB02: E/E and e/
LCG Meeting, May 14th 2003
V. Daniel Elvira 9
Pion peak
Muon background
Background subtracted pion peak
E/E = 20.3%
TB02: E/E and e/
50 GeV pions
Pions showering in the crystals
Data energy resolution for 50 GeV pions (almost negligible background close to the pion peak)
LCG Meeting, May 14th 2003
V. Daniel Elvira 10
TB02: E/E and e/
The agreement is excellent in all the energy range
Shape difference: e/h (e.m. & nuclear x-sec), leakage……?
Data systematic error analysis in progress
Validate GEANT4 physics models
Resolution Linearity
LCG Meeting, May 14th 2003
V. Daniel Elvira 11
Transverse Shower Profile
Future: remove ECal, add integrated profiles, longitud. profile studies, HO fraction & compare with OSCAR CMS & CMSIM (Salavat), and TB data (Jordan)
G4/OSCAR TB02
crystals
HB towers
Fill ( D, E )
With D: distance of crystal/tower to the pion direction E: energy deposition
LCG Meeting, May 14th 2003
V. Daniel Elvira 12
•TB02 OSCAR_1_4_0 fully functional. Validation studies in progress, for week data uncertainties are essential.
•Need to port the simulation to OSCAR_2, hopefully for next CMS week in June
fighting technical problems related to translation to XML, among other things
•Document on TB02 M.C. simulation by July
Summary & Plans
LCG Meeting, May 14th 2003
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Data & MC Electron Resolution
2.6% at 100 GeV for 3x3 tower matrix
2.8% at 100 GeV for 3x3 tower matrix
EECaltower EECal
tower+ 115 MeV * Rand
Electronic noise
M.C resol much lower than measurement
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V. Daniel Elvira 14
• EECaltower EECal
tower+ 115 MeV * Rand (noise)• 2.3%/ sqrt(Eele) (photo-statistics)• 0.3% (longitudinal non-uniformity)• 0.4% (calibration)
Other Contributions
No significant change
EECaltower EECal
tower+ match* Rand (To match the measured electron resolution)
•Temperature Resp=2%/oC
(crystals) 0.5%/oC (tubes)• Longitudinal crystal uniformity• Radiation damage
Causes (?):
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