Silicon Photomultiplier Performance

PDE measurements of Sensl 1mm devices (E. Smith)

The following numbers are taken from the first two rows of Zisis talk at the collaboration meeting (p 5, 1x1 mm² SiPM parameters)

Design	Pixels	DR @ 4V	Fill Factor	Dark Current	Peak PDE @ 4V
		(MHz)	(%)	(μA)	(%)
C20	620	2.9	17	-2	8.5
A20L	920	5.9	34	-3	17.0

From Carl's talk (p 37, QE and PDE), you can determine the ratio of the PDE@4V to PDE@1.2V, which was the chosen operating point for Carl's measurements. The ratio is approximately 2. Therefore, the expected PDE@1.2V for the C20 is about 8.5/2 = 4.2. Carl measured it to be 4.4 ± 0.5.

Conclusion: At the operating point of about 1.2 V above breakdown, the PDE for the C20 (1mm2, 17% fill factor) SiPM is about 4.5%. So far, our experience tells us that the practical operating point for these devices is about 1V over voltage. As the voltage above the breakdown increases further signal to noise decreases and even pulse shape become distorted.

If we use the A20L instead of the C20, the PDE will double, but so will the dark rate. We believe that the estimated 110  MHz rate for the 4x4 array is for the 1V over voltage, thereby consistent with a PDE of 4.5%.

Comments are welcome. In particular, it would be useful for Richard to remind us the conditions that were used for his measurements of the PDE for the 1x1 and 2x2 mm² SiPMs.

PDE measurements of Photonique SiPM devices (R. Jones)

The following numbers are taken from the report gluex-doc-760. They are consistent with the data sheets for these devices available on the photonique web site. The SSPM_050701GR_TO18 SiPM (first row in the table) is the 1 mm² device. It has a slightly higher peak PDE at 600 nm than the newer 4.4 mm² device (second row in the table) but, but the latter does not drop off as fast at shorter wavelengths and so is more efficient in the green-blue region.

Device	Pixels	DR @ 1.5V	Peak PDE	PDE(500nm)
		(MHz)	@ 1.5V (%)	@ 1.5V (%)
SSPM_050701GR_TO18	556	9.8	30	18
SSPM_0606BG4MM_PCB	1700	8.9	27	24