Objectives of the Shashlyk Calorimeter

• π/e discrimination
• energy, position and time measurement

TPR Layout of a Shashlyk module

Number of layers	378
Scintillator layer thickness	1.5 mm
Lead layer thickness	0.275 mm
Effective Moliere radius	59.8 mm
Radiation depth	20 X0
Lateral dimensions	110 x 110 mm2
Energy resolution	4.% / sqrt(E)
Time resolution	100 ps / sqrt(E)

Results of simulations

Piotr Hawranek performed simulations of the calorimeter electron/pion separation (Panda meeting Dec'06). He used the so-called old code. Simulation comprised:

• π^- and e^- beams of 1 and 5 GeV/c momentum
• setup with modules of various lateral dimensions

Detector response and cuts imposed in order to select electrons of 5 GeV/c momentum in the 110 x 110 mm² modules are shown as an example of the procedure.

Results of the simulations are summarised in the table below.

• 5 GeV/c

Module size	e- identified	π- identified as e-
30 x 30 mm2	84.6%	0.2%
55 x 55 mm2	93.3%	0.4%
110 x 110 mm2	97.4%	0.8%

• 1 GeV/c

Module size	e- identified	π- identified as e-
55 x 55 mm2	96.2%	4.7%
110 x 110 mm2	98.1%	8.7%

It should be stressed here, that the analysis procedure was rather rough. Certainly, application of a more sophisticated tools (e.g. Bayes theorem) could improve the results. The trend, however, is clear already from the presented numbers.

-- AleksandraWronska - 26 Apr 2006