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

LCG Meeting, May 14th 2003

V. Daniel Elvira 7

/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

V. Daniel Elvira 13

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

LCG Meeting, May 14th 2003

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 (?):