UTA GEM DHCAL Simulation
Jae Yu*
UTA DoE Site VisitNov. 13, 2003
(*On behalf of the UTA team; A. Brandt, K. De, S. Habib, V. Kaushik, J. Li, M. Sosebee, A. White)
•Introduction•GEM Geometry Implementation•Single Pion Study for GEM performances
•GEM Analog Mode•GEM Digital Mode
•Single Pion EFA Studies•Summary
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
2
Introduction• LC physics topics require excellent jet energy and
angular resolutions• Energy flow algorithm is one of the solutions• Large number of readout channel will drive up the cost
for analogue style energy measurement Digital HCAL• Tracking calorimeter with high gain sensitive gap
– GEM is one such detector technology • Simulation effort to understand detector progressed
along with prototype development– Thanks to the support from LCRD and ADR
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
3
UTA GEM Simulation • LC Physics Events: Pandora – Phythia • Use Mokka as the primary tool
– Kept the same detector dimensions as TESLA TDR– Replaced the HCAL scintillation counters with GEM
(18mm SS + 6.5mm GEM, 1cmx1cm cells) • Single Pions used for performance & EFA
studies– 5 – 100 GeV single pions– Analyzed them using ROOT
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
4
TESLA TDR Geometry
Ecal – Electromagnetic Calorimeter Material: W/G10/Si/G10 plates (in yellow)•1mm W absorber plates•0.5 mm thick Si, embeded 2 G10 plates of 0.8 mm each
Hcal – Hadronic CalorimeterMaterial:•18 mm of Fe •6.5 mm of Polystyrene scintillator (in green)
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
5
UTA Double GEM Geometry
3.4 mm ArCO2
GEM3.1 mm
Simple GEMDetailed GEM
0.
00
51
.
0
Cu
Kapton
ArCO2
G10
0.
00
5
6.5mm
Detailed GEM75GeV <E>=0.80 0.007MeV <E>=0.81 0.008MeV
Simple GEM75GeV
25.2sec/event for Simple GEM v/s 43.7 sec/event for Detailed GEM
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
6
Energy Deposit for 10 GeV Pions (GEM)
fEM>=0.85
Remaining Total
fHC>=0.85
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
7
GEM-Digital: Elive vs # of hits for π-
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
8
GEM Cell Occupancies
~85% single hit
~15% >1 hit
~74% single hit
~26% >1 hit
Number of cells with higher number of hits increase w/ E
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
9
N vs Layer
Energy Deposit/Ncells vs Layers for 50 GeV Pions
E vs Layer
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
10
Extraction of of dE/dN
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
11
EM-HAD Relative Weighting Factor • To compensate the response differences
between ECAL and GEM HCAL responses a procedure to normalize them had to be introduced– ELive=EEM+ W gEHAD (g:GEM Intrinsic gain)
– Obtained the relative weight W using two Gaussian fits to EM only v/s HAD only events
– Perform linear fit to Mean values as a function of incident pion energy
– Extract ratio of the slopes Weight factor W– E = C* ELive
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
12
GEM – Relative Weights
Analog
Digital
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
13
GEM-Digital: Live Energy 50 GeV π-
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
14
GEM – Normalized Response
Analog: 2.4%
Digital:2.6%
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
15
Converted energy: 50 GeV π-
Analog
DigitalFits are Landau + Gaussian
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
16
Resolutions
Digital GEM
Analog GEM
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
17
EF Technique
C 2
C 3
C 5
C 7
C 4
C 6
C 1
ij CENormal Calorimetric Method:
p2p3 p5
p7
Energy Flow Method:
nCpE ij
Only susceptible part to Shower statistical fluctuation
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
18
• Charged particle energy subtraction based on track-cluster association is important to EFA
• The algorithm must work well with single particle case• Pions E π- = 7.5 GeV chosen for study• Studied the energy distribution of pions in jet events
• Find the centroid of the shower ( HCAL ) using– Energy weighted method– Hits weighted method– Density weighted method
• Match the extrapolated centroid with TPC last layer hit to get Δ and Δφ distribution
Energy Flow Studies Using π-
TeVsjetsttee 0.1 @ 6
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
19
• Energy Weighted Method
• Hit Weighted Method
• Density Weighted Method
Calorimeter Centroid Determination
n
n
jij
i
1
n
n
jij
i
1
401:
:
1:
i
ilayerinhitsofNumbern
nj
n
jij
n
jijij
i
E
E
1
1
n
jij
n
jijij
i
E
E
1
1
401:
:
1:
i
ilayerinhitsofNumbern
nj
n
ijj iji Rd
,1
1
n
jij
n
jijij
i
d
d
1
1
401:
:
1:
i
ilayerinhitsofNumbern
nj
n
jij
n
jijij
i
d
d
1
1
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
20
Event Displays
E=50 GeV
6 jets
Single
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
21
Neutral particles
Number of charged and Neutral particles
Charged: e, , K
<N>~12 <N>~6
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
22
R of all the particles relative to quark
R flattens out after 0.3
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
23
E weighted vs Numerical Mean)
E = 50 GeV1cm x 1 cm cells
E weighted
<>=-3.1x10-5
=1.1x10-2
Numerical Mean
<>=-1.2x10-3
=2.5x10-2
Analog seems to be better than digital but not by significant factor
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
24
- 7.5 GeV π-
Energy Weighted
Hit Density Weighted
Bug???
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
25
Summary• Made a marked progress thanks to the LCRD and ADR
support• Completed single GEM DHCAL performance studies
– Initial study documented in Habib’s MS thesis– More detailed and refined study being completed by Kaushik– Analog resolution seems to be worse compared to other detector
technology due to large fluctuation in initial ionization electrons– Digital, however, performance is comparable to other analog
technologies• Released our Pandora – Phythia ASCII and other analysis
packages to LC software group per their request
Nov. 13, 2003 Status of DHCAL Simulation, J. Yu
26
• EFA studies in progress– Study track – cluster association and energy subtraction using
single pion Three methods being investigated– Study typical distance between charged particles within the jet– Determine necessary resolving power for realistic situation
• Prepare for larger scale prototype, cosmic ray stack and TB simulation
• Development of analysis software• Continued and increased support is critical to make the next
quantum jump