1. SiPM calibration
Tagir Aushev (ITEP)

2. Proposal There 18 000 SiPM’s must be calibrated
SiPM’s properties vary from one to another
some SiPM’s can be bad
to optimize total efficiency, all SiPM are preferable to have similar gain/efficiency/etc. and to reject the bad one
Some tests are already done in both, ITEP and U of Tabuk
using small number of SiPM’s calibrated simultaneously
New device will calibrate a large amount of SiPM’s
reduces the total calibration time to reasonable level (1-2 months)
The proposal is to develop such a device with combined efforts of ITEP and U of Tabuk groups, who have some experience in it

3. Testing SiPMs at the U Tabuk
done for Large Angle Beamstrahlung Monitor(LABM) by R. Ayad, C. Boulahouche, J. Madani
to detect synchrotron radiation at large angle (beamstrahlung) to study beam-beam effect
Later SiPMs from Advansid(Italy) to be used
to save size in the optical Box and for robustness
Optical Box: First we use PMs

4. SiPM tests at U of Tabuk Lab DAQ Dark Pulses and baseline change
With temperature
Channel by Channel Threshold Finding

5. Plans & schedule
First step is to develop the principal scheme of the device
3 person x month
Build a low channel prototype
4 person x month
Develop DAQ system to collect, store and manage data
Write a software to automatically analyze data from SiPM’s
The building of the prototype can start now
there is an available funding of about $25k
We (ITEP & U of Tabuk) submit soon application for Grants in SA
the decision will be made around June, 2013
The man power for the calibration will be provided by U of Tabuk

6. Backup

7. SiPM operation ΔHV = 1.4 V ~ 70 V 1 – 1.5 V HV = HVbreak down + ΔHV
HVbreak down strongly depends on temperature: ~ 57mV/°C;
all important for us SiPM characteristics (gain, efficiency, xtalk, noise) depends only on ΔHV – independently of temperature!
choose working point:
efficiency < saturation
noise (at 0.5 p.e.) < 1 MHz
xtalk < 20%
to have maximum efficiency but staying in the linear region (robustness against temperature changes)
SiPM noise 8 p.e. threshold)
< 1kHz << neutron bg rate
To stay at the operation point it is sufficient to adjust HV to keep gain constant at chosen value
ΔHV = 1.4 V

8. SiPM data base & distributions
For 200 SiPMs available at ITEP we measured main characteristics and put them to SiPM db
No big spread! Do we need calibration for the rest SiPMs?