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Forward end-cap challenges. Gamma rays Doppler shifted to high energy High-density, high resolution needed Crucial kinematics domain for simultaneous detection of protons Reactions Add-back@300MeV -> 60% “efficiency” (p,2p) 36% “correct” How to distinguish?? ∆E Si + E CsI
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Forward end-cap challenges • Gamma rays Doppler shifted to high energy • High-density, high resolution needed • Crucial kinematics domain for simultaneous detection of protons • Reactions • Add-back@300MeV-> 60% “efficiency”(p,2p) 36% “correct” • How to distinguish?? • ∆ESi + ECsI • ∆ESi + ∆E1 + E2 • ∆ESi + ∆E1 + ∆E2 GEANT4 simulation (Lund Univ) for 180 MeV protons in CALIFA CsI crystal Total loss =52.1 % CALIFA meeting
Ep= 200MeV 30mm LYSO DE = 67.5±1.8 MeV 200±7MeV (sE/E=3.5%) Ep= 200MeV 20 mm LaBr DE = 31 ± 1 MeV 200±10MeV (sE/E=5%) Phoswich: p- Energy resolution E DE1+s (DE1) DE2+ s (DE2) • Protons: Using two DE-detectors one can determine the full proton energy with a resolution of <5%. • Gammas: Second detector placed to solve the ambiguity on the signal E =f(D E1 )+ g(D E2)
Phoswich prototype – gamma response Conventional electronics Sampled (1 Gs/s) anode pulse FWHM 2.4%@ 662 keV CALIFA meeting
Phoswich prototype – proton response Pulse integral [a.u.] 180+155 MeV protons Pulse height[a.u.] Sampled (1 Gs/s) anode pulse decay time= 16(LaBr)/28(LaCl) ns CALIFA meeting
Tracing protons… 100 – 190 MeV 190 MeV 190 – 400 MeV 100 MeV 0-100 MeV IWM2009 – Nov. 5 2009
