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Hadron Calorimeter

Hadron Calorimeter. Hadron Calorimeter HCAL- J. G. Franklin, Carnegie Mellon University. GEp Electron Calorimeter BigCal. 10/13/2011. Hadron Calorimeter. Match acceptance of SBS magnet/ polarimeter Run with high threshold while maintaining high trigger efficiency

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Hadron Calorimeter

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  1. Hadron Calorimeter Hadron Calorimeter HCAL-J G. Franklin, Carnegie Mellon University GEp Electron Calorimeter BigCal 10/13/2011

  2. Hadron Calorimeter • Match acceptance of SBS magnet/polarimeter • Run with high threshold • while maintaining high trigger efficiency • Linear energy response • 0.5 ns time resolution • 5 mrad angular resolution Requirements for the SBS experiments:

  3. COMPASS HCAL1 Module Design • 40 iron/scintillator layers (~ 5 ¸nucl) • 2.0 cm iron plates • 0.5 cm scintillator plates • 14.2 cm x 14.6 cm • 120 cm long wave-shifter readout along 1 side • 6 photo-electrons for min-ionizing thru one scintillator PMT

  4. HCAL-J Design HCAL-J based on COMPASS HCAL1 Each module: 15 cm x 15 cm Layered scintillator and iron 24 Modules (360cm) Replicate with small design modifications 12 Modules (180 cm) Existing HCAL1 in COMPASS 288 modules for JLab HCAL

  5. JINR (DUBNA) produced 9 HCAL modules of COMPASS design Funded by CMU Integral WLS/ Light guide Acrylic with Coumarin-7 impregnated surface 5 mm thick 40 layers 20 mm iron / 5 mm scintillator Novel light guide for 1 in PMTS Steel casing Hole in downstream light guide HCAL-C Module shown on its side (WLS and side cover removed)

  6. COMPASS Light Guide /WLS

  7. Geant4 Energy Resolution Studies ¼ signal thresh. ½ signal thresh.

  8. Geant4 Spatial Resolution Results JLab kinematics Agreement with COMPASS data Achieves required angular resolution with HCAL positioned 17 m from target: 5 cm / 17 m !3 mrad resolution

  9. Geant4 Timing Simulations • Waveshifter decay time • 8 ns ! 3.5 ns • PMT rise time • 10 ns ! 2.5 ns • Maximize Npe • 0.5 !1.0 cm scint. FWHM = 1.12 ns ¾ = 0.48 ns FWHM = 2.1 ns ¾ = 0.9 ns Trigger Time (ns) Trigger Time (ns) Simulation using faster waveshifter dye and PMTs Meets SBS requirements To be confirmed with prototype HCAL module Simulation using COMPASS parameters Agrees with published COMPASS HCAL performance

  10. Use commercial WLS with fast decay time Need light guides

  11. Possible Fast WLS Solutions EJ-299-27 WLS Decay time 1.5 ns Or BC-484 WLS Decay time 3 ns EJ-299-27 BC-484 Can’t be excited with “typical” PPO / POPOP scintillator WLS scintillator PPO/POPOP Scintillator emission not matched to WLS absorption

  12. Possible Solutions for Scintillator • BC-420 $ 1,140k • Alternative PPO scintillator< $ 100k • JINR Production • FNAL Extrusion + CMU Machining • Issues • Short attenuation length at short wavelength • Delays in initiating production of PPO-only samples at JINR • 15 cm too wide for FNAL extrusion • Two problems solved with design change • Design with WLS down center of each module • 7.5 cm scintillator on each side • Double # iron plates (increases cost by 20%)

  13. GEANT4 Optical Monte Carlo Light Pipe Design Studies (VaheMamyan) For offset WLS For centered WLS Design 1 For centered WLS Design 2 Results for simulated light transmission Assumed 90% reflective

  14. Light Guide Production • Found company (ICOMold) that can injection mold large pieces with optical-quality surface • $10k tooling for mold • $12.59/piece cost • For 300 pieces: $10k + $ 3.8k = $ 13.8k

  15. Recent Developments • Vincenzo Bellini group (INFN/Catania) has joined (with funding) • New WLS quote from Saint Gobain • Pending • Sample WLS delivery from Saint Gobain • Sample scintillator from JINR (delivery unclear) • Sample scintillators from FNAL, PPO concentration from 0.5% to 3%, (November) • Sample molded object from ICOMold for reflectivity tests

  16. Cost estimate ~300 modules

  17. HCAL-J Project Timeline • FY12 Prototype Module Testing • Cosmic ray uniformity tests • Background measurements • Test scintillator and waveguides options • Design Finalization • Jan 2013Order scintillator • Order WLS, Light Pipes • Start end-plate and box construction • Order Iron • April 2013 Start scintillator chop and mill • Module assembly 9 to 12 months • April 2014 Complete modules

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