especially concerning optimization of identification power, energy resolution, efficiency, optimal readout device for the barrel part of CALIFA, a calorimeter to be used by i.e. in an energy interval between the Deep Inelastic/Incomplete Fusion region where EMRIC (CsI) operated and the Quark-gluon plasma region where ALICE/PHOS (PWO) wil l operate (particle physics CsI calorimeters – BaBar and BELLE (30.3 tons of CsI)). for Reactions with Relativistic Radioactive Beams Bo Jakobsson, LU: R3B Collaboration meeting, GSI, April What we learnt about CsI(Tl) as calorimeter detectors-- EXL

*) The producer should deliver polished crystals with monotonously decreasing LO. The proposal by CMS (PWO det.) to paint some parts of side areas black is not possible with CsI. It can be replaced by black scotch but even better is to lap the side areas up to the ”inflection point” This is done in    20 – 30 min / detector by the users    no loss i LO Energy resolution (large scale production)* - The light output (LO) non-uniformity (doping concentration) must be corrected in any finger-type CsI(Tl) detector!

10x30x100/130 mm 3 two-truncated pyramide (USC) type 20x20x110 mm 3 δE/E, 0.5 – 0.9% δE/E, 0.4 – 0.7 % LO (a.u.) TSL test with 179 MeV protons show small differences in the energy resolution between,

The error in the determination of a2 gives some finite contribution to the resolution TSL test with 179 MeV protons shows that response function must be controlled

Gamma source data + GEANT4 simulated response in USC type detectors APDs are superior. PD and PMT readout is acceptable for ideal one-detector exposure but much worse when signal addition is needed? What we learnt about gamma resolution is up to now based on....

GEANT4 simulations of detector response [D. Di Julio, J. Cederkäll] 2. TSL proton data is now compared to simulations. First observation -When adding signals the resolution is destroyed and even new peaks appear in the spectra. This is interpreted as a result of using one unique response function. Individual response functions are needed. Tuning of GEANT4? Even more important – simulation of gamma response. 500 keV gammas hitting the central detector of the 3x5 CALIFA array

What we learnt and what is still missing – readout PDs are excellent for proton and light charged fragments but not (yet) acceptable for gammas because of too high threshold and noise level which makes signal adding particularly bad. Some new results for the PANDA APD S on CALIFA detector and ALICE/PHOS PA are  Temperature (°C) We propose for the TUD gamma test: - to operate at a temperature close to 0 ºC (~ +2 ºC) -to use extra stable power supply e.g. from providing ΔV= 0.1 V for ΔT = ±5 ºC -to consider having extra thermal isolation between detector boxes (aerogel?) Can the large dynamic range be handled with two readout channels – APD + PD ??

M2J MATA CO32 CAEN Vl729 for temp. and HV control CAEN V1724 Flash ADCs focal plane radiator magnet coincidence experiment 1 m electrons photons focal plane radiator magnet coincidence experiment 64 ch Mesytec CSPA What we need now is the – gamma test at NEPTUN hopefully in September!

What is still missing – forward cap decision LU optional forward detectors Gamma source measurements with tentative? CALIFA forward cap CsI geometry,PANDA APD readout ALICE preamplifiers and T +V stabilization Compare to barrel detector performance!

The test run at The Svedberg Lab. was really successful thanks to, Vladimir Avdeichikov, Pavel Golubev, Douglas di Julio, Joakim Cederkäll et al., LU Håkan Johansson, Thomas Nilsson et al. Chalmers Martin Gascon et al,, USC Olof Tengblad et al.,CSIC And thank you Uppsala University for providing free beamtime!