sbs hadron and electron calorimeters mark jones 1 texpoint fonts used in emf. read the texpoint...
TRANSCRIPT
slide1
SBS Hadron and Electron Calorimeters
Mark Jones
slide2
SBS Hadron and Electron Calorimeters
Mark Jones
•Overview of GEn, GMn setup
•Overview of GEp setup
•The SBS hadron calorimeter (HCalo)•Design of HCalo•Neutron and proton detection efficiency, energy and position
resolution
•BigCal for GEp (not part of this technical review)
slide3
Experiment Setup for GEn and GMnUse standard BigBite double layer calorimeter
• Electron PID (combined with gas Cherenkov). • Electron energies in range from 1.2 to 3.5 GeV. High threshold for trigger.
Hadron calorimeter based on successful design used in COMPASS. • Proton and Neutron momentum from 2.6 to 10.5 GeV/c
•Need good position (angular) resolution to separate (quasi-) elastic from inelastic background.
slide4
Experiment Setup for GEp Reconfigure BigCal for electron detection.
• Electron momentum range from 3.3 to 3.9 GeV/c• Use 20cm thick Al wall to reduce flux of low energy background.• High threshold to reduce single arm trigger rate.• Position resolution needed in track reconstruction ( L. Pentchev’s talk)
Use same Hadron calorimeter• Proton momentum range from 3.5 to 8.6 GeV/c• High threshold to reduce the single arm trigger rate• Position resolution needed in track reconstruction
slide5
Module of Hadron Calorimeter•As starting point, use COMPASS design of JINR group.
Iron and scintillator sandwich
slide6
Module of Hadron Calorimeter Carnegie Mellon and JINR will design and build calorimeter.
• Optimize length for the experiment’s energy range• Improve timing resolution.
o COMPASS Dt = 1.5ns o Expect to reach Dt = 0.4ns
slide7
Hadron Calorimeter (Hcalo)
• Each block has frontal area 15x15 cm2
•Arrange 11x22 blocks
•Area = 5.5 m2
•Total weight is 36 tons (w/o frame)
slide8
COMPASS HCalo Performance
Position resolutionIn range of 2-10 GeV/cDE/E = 20-30%
Energy resolution
slide9
GEANT study of HCalo Performance
Response of neutrons and protons nearly identical Good energy resolution
slide10
GEANT study of HCalo Performance
Response of neutrons and protons nearly identical Good energy resolution
• High thresholds reduce backgrounds• GMn: Near identical p/n efficiency reduces systematics
slide11
GEANT study of HCalo Performance
Response of neutrons and protons nearly identical Good position resolution
• GMn, GEn, GEp: Cut on Qnq to separate (quasi-)elastic events• GEp : Need for track reconstruction, reduce pseudo-tracks
slide12
BigCal for GEp experimentUsed in Hall C Gep3 experiment
slide13
BigCal performance in Hall C GEp3Comparison of energy resolution from GEANT simulation to data for different electron energies and thicknesses of Al plate
Agreement between GEANT and data is excellent
slide14
BigCal performance in Hall C GEp3xcal is measured BigCal horizontal coordinatexHMS is predicted position from beam energy & proton momentum
DxHMS = 0.9 cm
Dxcal = 0.55 cm
xdiff = xcal -xHMS
¢ x2cal = ¢ x2di®¡ ¢ x2HMS
slide15
BigCal for GEp
Reassemble 20 x 76 block array. 1520 blocks
Block size is 4x4x40 and 3.8x3.8x45 cm3
Covers area of 0.80 x 3.04 = 2.4 m2
76
20
slide16
BigCal electronics
76
20
Make groups of 4x2 blocks Use NIM “summing” modules
(special built for and used in Hall C experiment) which have:
• 8 analog inputs• 8 analog outputs (amplify 5x)• 6 “sum of 8” analog outputs
slide17
BigCal electronics
Each red block is 4x2 grouping into NIM “summing” module.
Need 5x38 = 190 modules (available)
38
5
slide18
BigCal electronics
For trigger form “group of 32” by summing analog output of 4 of “group of 8”. (Use available Lecroy NIM FI/FO)
Blue box represents one “group of 32”
38
5
slide19
BigCal electronics
For trigger form “group of 32” by summing analog output of 4 of “group of 8”. (Use available Lecroy NIM FI/FO)
Blue box represents one “group of 32” Turquoise box is next “group of 32” in
vertical which overlaps by 2 rows. 38
5
slide20
BigCal electronics
For trigger form “group of 32” by summing analog output of 4 of “group of 8”. (Use available Lecroy NIM FI/FO)
Blue box represents one “group of 32” Turquoise box is next “group of 32” in
vertical which overlaps by 2 rows. Dark green is next group
38
5
slide21
BigCal electronics
For trigger form “group of 32” by summing analog output of 4 of “group of 8”. (Use available Lecroy NIM FI/FO)
Most “groups of 8” are in 4 “groups of 32”
38
5
slide22
BigCal electronics
Each dot is the center of “group of 32”
Have 4x37 = 148 “group of 32” which will be used in trigger.
Trigger discussed in O. Hansen’s talk.37
4
slide23
Conclusions Hadron Calorimeter
• Used in all three form factor experiments.• Based on the proven COMPASS design.
• Energy resolution allows high thresholds to eliminate background and lower trigger rates
• Position resolution allows for good angular resolutiono Needed in all FF experiments to separate (quasi-)elastic from inelastico Needed in GEp to help in tracking with large low-energy background rates
• Neutron and proton response above 2.5 GeV/c nearly identical Electron Calorimeter
• GEn and GMn use standard BigBite calorimeter• GEp uses a reconfigured BigCal calorimeter• High threshold reduces trigger rate• Position resolution needed for tracking and separating (quasi-) elastic from inelastic.
slide24
Backup Slides
slide25
GEANT study of HCalo Performance
•Response of neutrons and protons nearly identical
F.
F. Benmokhtar
Protons
Neutrons 2.5 GeV/c3.2 GeV/c4.0 GeV/c5.4 GeV/c6.2 GeV/c7.3 GeV/c8.1 GeV/c9.4 GeV/c10.5 GeV/c
slide26
GEANT study of HCalo Performance
•Response of neutrons and protons nearly identical•Good energy resolution
• High thresholds reduce backgrounds• GMn: Near identical p/n efficiency reduces systematics
F. Benmokhtar
slide27
GEANT study of HCalo Performance
•Response of neutrons and protons nearly identical•Good position resolution
• GMn, GEn, GEp: Cut on Qnq to separate quasi-elastic events• GEp : Need for track reconstruction, reduce pseudo-tracks
F.
F. Benmokhtar
slide28
COMPASS HCalo Performance
Muons
Pions
Extensive tests of calorimeter performance were done at CERN for pions, electrons and muons at 2-100 GeV
Calibrated energy spectra for 10 GeV beam
slide29
COMPASS Hcalo
slide30
GEp experiment
slide31
GEp experiment: Radiation Damage
slide32
GEp experiment: Radiation Damage
slide33
GEn experiment
slide34
GMn experiment
slide35
GMn experiment
slide36
Geant study of HCalo Performance
•Response of neutrons and protons nearly identical•Good position resolution
• GMn, GEn, GEp: Cut on Qnq to separate quasi-elastic events• GEp : Need for track reconstruction, reduce pseudo-tracks
•Good energy resolution• High thresholds reduce backgrounds• GMn: Near identical p/n efficiency reduces systematics