1. Characteristics of S12045(X) photon sensors for GlueX
Barrel Calorimeter for GlueX
Silicon Photomultiplier Photodetectors
Characteristics
Operation
Summary

2. BCAL: GlueX Barrel Calorimeter
BCAL design modeled after KLOE EMC
48 modules (phi sectors)
Readout unit
SiPMs
Light guides
12 mm
Module: 191 layers
Pb/Sc/Glue 37/49/14%
Immune to magnetic fields!

3. BCAL Photodetectors Hamamatsu S12045(X) MPPC array:
Silicon Photomultiplier (SiPM)
Arrays of 16 3x3mm2 cells, pixels 50x50 mm2
Gain ~106, dark rate ~15MHz/array at 250C
Insensitivity to magnetic fields!
Operation ~ Vbr+1V ~ 75 V
Sensitivity to radiation
Properties unaffected except for dark rate, which increases proportionally to radiation dose.
Lifetime of SiPM in Hall D estimated ~ 9 years at T=5oC
12 mm
Qiang NIM A698 (2013) 234
Experience
T2K experiment deployed 53, x1.3mm2 S C sensors
Hall D is the first large-scale application of SiPM arrays
Barbosa NIM A695 (2012) 100

4. S12045(X) Hamamatsu MPPC array
Array of 16 cells
3600 pixels/cell
Back side can be cooled
16 Pins, one for each cell
4 bias supplied, one per row
12.7 mm
GlueX: 1 bias
1 summed output

5. Lightfoot et al., J. Inst., Oct. 2008
Gain vs Temperature
Lightfoot et al., J. Inst., Oct. 2008
T = -196 oC
T = 25 oC
Vbr as temp. decreases

6. Photodetectors for GlueX
The GlueX experiment requires a total of 4000 arrays
All sensors have been delivered and tested.
30% were tested at Jefferson Lab
70% were tested at the Universidad Técnica Federico Santa María (USM), Valparaíso, Chile
Four units failed our specifications
Good consistency between test results
University of Regina
10 units tested using realistic BCAL fiber spectrum
Jefferson Lab Tests
Measurements performed at 15oC
Response measured for each of the 16 cells
Five different light input levels
USM Tests
Measurements performed at 5, 7 and 20oC
Response measured for each of the 16 cells
Two different light input levels
Voltage scan performed for each measurement

7. Determination of SiPM characteristics
ADC (counts)
pedestal
1 pixel
2 pixels
3 pixels
4 pixels
5 pixels
Spectra for each cell in the array is used to determine gain, cross talk and dark rate
at three different temperatures 5, 7 and 200C
Photon Detection Efficiency
(PDE)
is determined using a calibrated light source

8. Cross talk and afterpulsing ~ 28%
Parameters at 15oC
<Gain> =
7.5 x 105
<PDE> = 23%
<Dark Rate> =
10 MHz/array
Cross talk and afterpulsing ~ 28%

9. Gain dependence on operating voltage

10. Summary of sensors for GlueX BCAL
Testing status
4000 S12045(X) Hamamatsu MPPC arrays have been purchased and tested for use on the GlueX barrel calorimeter
The performance of each of the 16 cells in the arrays has been tested at a variety of temperatures, bias voltages and light intensity settings.
All sensors exceeded our specifications
Next steps
Sensors are being incorporated into readout modules that will be mounted on the barrel calorimeter
Preparations are being made to deal with the operational challenges of these detectors (narrow voltage operating range and sensitivity to temperature).