1. Prototype activities update
W. Baldini on behalf of the Ferrara IFR Group
XXVII SuperB Workshop and Kick off Meeting Isola d’Elba May 28 - June

2. Prototype activities in Ferrara
After the Fermilab beam test the prototype has been shipped back and is now installed and running in Ferrara
The configuration is the same as at Fermilab:
Same Pizza Box configuration (CP1)
Distances among PB are the same
No Iron
We are following the plan showed in Frascati in April:
Taking cosmic data overnight with different working conditions (Vbias , thresolds ..)
Improvements, debugging and other measurements during the day
Pizza Boxes

3. Plans for cosmic data taking (from frascati meeting)
At the very beginning triggering with the upper and lower-most layers, mainly for debugging purposes
As soon as we reach a stable condition, switch to an external scintillator trigger and measure:
Efficiency and time resolution for different SiPM bias voltages (to understand a strange behaviour of some the testbeam)
Number of p.e./mip for the different combinations of scintillator-fibers-SiPM (at the testbeam not enough time…)
Test the special module with MPPC (not tested at the Dic. testbeam)
Comparison with testbeam data
Done
Done
Ongoing
Ongoing

4. Cosmic Data Taking schedule
Date
Filename
Start
Stop
N evts
Run # Comments
May 11
FEEConfig_base
Baseline conf. (G=14,17)
May 12
FEEConfig_High_Gain
High Gain (15,18)
May 13
FEEConfig_High_Gain_2
High Gain (16,19)
May 14
FEEConfig_AllV_32.75V
All 32.75V
May 15
FEEConfig_AllV_33.00V
All 33.00V
May 16
FEEConfig_AllV_33.25V
All 33.25V
May 17
FEEConfig_AllV_33.50V
All 33.50V
May 18
FEEConfig_AllV_33.75V
All 33.75V
May 19
FEEConfig_AllV_34.00V
All 34.00V
May 20
May 21
May 22
May 23
Pulser – th scan
Random trigger
May 24
May 25
May 26
Due to problems with the high temperature (up to 32 C) some runs have to be
repeated see Gigi’s Talk on Tuesday

5. Light Yield measurement
Measure how many p.e. we have for different options:
Scint. 1 or 2 cm thickness
WLS fibers 1.0 mm vs 1.2 mm in diameter
SiPM 1.2x3.2 mm2 (4020) vs 1.4x3.8 mm2 (4380)
The method is very simple:
measurement of the gain (2pe – 1pe) on the Dark count spectra
In the same conditions (Vbias,T) measure the average signal on cosmics, triggering on the other SiPM of the same scintillator, with a high threshold (5-6 pe).
Npe= Average-signal/G

6. Light Yield Measurement: the method
1 pe
2 pe
Gain
Dark count (low Thr)
Cosmic Signal (High Thr on other SiPM)
signal
pedestal
Npe = (sig. – ped)/Gain

7. Light Yield Measurement: preliminary results
Fiber length L=3.25m
Fiber length L=0.75m
Pizza box #1 (scint=2cm, fib=1.0mm, SiPM=4020 )
This are very preliminary results, high temperature
(up to 32 °C, no air conditioning yet…)

8. Light Yield Measurement: next steps
Measure the light yield for other configurations:
PB #5 : fibers 1.2mm in diameter and SiPM 1.4x3.8mm2
PB with 1cm scintillator and Kuraray 1.0 and 1.2mm fibers
Measure precisely the temperature dependence of Gain (and Dark Count rate) in order to make corrections on Vbias settings
Test MPPC module (PB #7) and compare with SiPM

9. Preparation for the next testbeam
Exploit the previous experience to optimize the next data taking:
Cerenkov cables: prepare 75W  50W adapters
larger S3,S4 scintillator
Faster S1-S2 scintillator (or use the TOF)
…. Other??
Cerenkov gas: check if the bottle is still full
Understand how to reduce SiPM temperature on site
Start shipping procedure…

10. Next main activities
Testbeam in July-August (Ju;y installation, July 20 – Aug 3 data taking
Testbeam data analysis and comparison with MC simulations
Radiation damage test (LNL or ENEA) :
monitoring of current, Dark Count rate, Gain vs dose
direct comparison unshielded/shielded devices
comparison SiPM and MPPC
Design of SiPM Mass Characterization setup
TDR: collect all data and start writing