SBS Hadron and Electron Calorimeters

Mark Jones

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

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 separated (quasi-) elastic from

inelastic background.

Experiment Setup for Gep Reconfigure BigCal for electron detection.

• Electron energies range from 3.1 to 4.0 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 8.8 GeV/c• High threshold to reduce the single arm trigger rate• Position resolution needed in track reconstruction

Module of Hadron Calorimeter•As starting point, use COMPASS design of JINR group.

Iron and scintillator sandwich

Module of Hadron CalorimeterAs starting point, use COMPASS design of JINR group.

•Optimizing design for experiment’s energy range.Carnegie Mellon and JINR will design and build calorimeter.

Hadron Calorimeter (Hcalo)

• Each block has frontal area 15x15cm

•Arrange 11x22 blocks

•Area = 5 m2

•Total weight is 36 tons.

COMPASS HCalo Performance

Muons

Pions

Extensive tests of calorimeter performance were done at CERN

Calibrated energy spectra for 10 GeV beam

COMPASS HCalo Performance

Position resolutionIn range of 2-10 GeV/cE/E = 20-30%

Energy resolution

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

GEANT study of HCalo Performance

•Response of neutrons and protons nearly identical•Good position resolution

•GMn, GEn, GEp: Cut on nq to separate (quasi-)elastic events•GEp : Need for track reconstruction, reduce pseudo-tracks

BigCal for GEp experiment

• Reassemble 20 x 76 block array. 1520 blocks

•Block size is 4x4x40 and 3.8x3.8x45 cm3

• Covers area of 3.04 x 0.80 = 2.4 m2

• Actual shape of configuration will match curved shape expected for elastic events.

BigCal for GEp experiment

• 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

• Each red block is 4x2 grouping into NIM “summing” module. •Need 5x38 = 190 modules (available)

BigCal for GEp experiment

• 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”

BigCal for GEp experiment• 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.

BigCal for GEp experiment• 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

BigCal for GEp experiment• 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”

BigCal for GEp experiment

• 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.

Conclusions Hadron Calorimeter

• Used in all three from 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 resolution

oNeeded in all FF experiments to separate (quasi-)elastic from inelasticoNeeded in GEp to help in tracking with large low-energy background rates

•Neutron and proton response above 2.5 GeV/c nearly identicalElectron 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.

Backup Slides

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

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

GEANT study of HCalo Performance

•Response of neutrons and protons nearly identical•Good position resolution

•GMn, GEn, GEp: Cut on nq to separate quasi-elastic events•GEp : Need for track reconstruction, reduce pseudo-tracks

F.

F. Benmokhtar

COMPASS Hcalo

GEp experiment

GEn experiment

GMn experiment

GMn experiment

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