1 Methods of PSD energy calibration

2 Dependence of energy resolution on many factors Constant term is essential only for energy measurement of single particle. It is not important in case of measurement of total energy from many particles with the same energy:

3 PSD calibration Sep 2011 PSD calibration was done with 158 GeV protons in parallel with physics run. Calibration with muons was not possible. Calibration parameters for each section of module have been obtained by solving the linear system of 10 equations. Rather complicated method, consists of a few stages, needs good alignment of beam spot with the center of module. MC ~ 6.5% Mean valuesEnergy resolution all modules clusters 2011 PSD calibration parameter set is in SVN and SHINE

4 Matrix method of energy calibration with protons A j 1-10 – amplitudes of the signals in sections 1-10 for event j C 1-10 – calibration parameters for sections 1–10 (to be found) Ten sequential events are used to find 10 unknown calibration parameters in 10 sections of one PSD module Calibration was done with GeV, each module was scanned

5 CLUSTER 1: hit module – small module 6 Deposited energy GeV Resolution 7.6% CLUSTER 2: hit module – large module 25 Deposited energy GeV Resolution 7.1% Deposited energy in clusters reconstructed with final calibration parameters Module 6 Module 25 MC expected resolution ~6.5% Beam spots Cluster 2 Cluster

6 Signal spectra in small module 8 Pedestal spectra Signal spectra in large module 20 Pedestal spectra PSD calibration was done with 100 GeV muons and muon beam trigger MAPD voltages have been increased comparing with HV used in Electronics noise was significantly reduced. Straightforward method – the calibration parameter is the ratio of muon energy deposition in the module section ( ~ 5 MeV) to ADC value. PSD calibration June 2012

7 Calibration results (June 2012) 158 GeV proton energy reconstruction with all modules and with clusters 2 Mean values Energy resolution MC ~ 6.5% 2012 PSD calibration parameter set is in SVN and SHINE

Test of one PSD section reveals peak in energy spectrum from cosmic muons Approach in calibration with cosmic muons Trigger was done by outer counters. Can self-ltrigger mode work in PSD? Identification of muon in presence of noise?

Approaches in pile-up detection by PSD (how many PSD channels must have extended length of 8  s) Two types of pile-ups: 1.Pile-up of ions in beam Might be detected by a few PSD modules near the beam axis. Only a few (4) extended channels are needed. 2. Pile-up of interactions in target. Must be detected by full PSD (44 modules). Adder unit has 8 sections with 8 inputs each. One can suggest to analyze each group of 8 modules. Six extended channels (8  s) are needed. 9