SiPMs

Useful resources:

XAMS SiPMs

Data sheet

XAMS readout board design shown below.

Circuit design of signal filter boards used in XAMS lab.

Sensor troubleshooting

How to connect the sensor

The SiPM has a cathode and an anode as can be seen in the schematic drawing below, the drawing also shows how the SiPM is oriented as a diode. A SiPM needs to be reversed biased, which means the voltage at the cathode is higher than at the anode. This way there is no current flowing until the electric field is so high the SiPM brakes down, the brake down voltages of the used SiPMs is also shown below. Sensor 1804 was already marked as defect, but we still used it to test our electronics just to be sure it worked without breaking a new sensor. This sensor first gave signals which made it seem like it was still working, but after switching around electronics we were not able to get a signal. We therefore decided to check all the used sensors if they are broken.

Schematic drawing of the S13370-3050CN SiPM

Serial No. Vop at M=2.55e6 [V] Id at Vop [μA] 1804 56.58 0.46 1805 56.69 0.47 1822 56.51 0.50

Wanting to check if a sensor is working correct we asked Martin van Beuzekom for the R & D lab to help us and helped us with a method to determine if a sensor is broken. First we wanted to check if the anode and cathode were indeed oriented as was depicted on the schematics. To check this we need to characterize the voltage vs. current. The characteristic graph of how this would look like could be found below. So what we do to check, is connect the SiPM with what we think is the cathode to the positive of the voltage source and the anode to the negative. We then apply a very low (around 0.1 [V]) voltage on the SiPM and increase it in steps of 0.1 [V]. If the diode is broken the current will increase linearly, and when the voltage applied is negative it will be again linear. This implies the diode is just an open connection and thus broken. If when the positive voltage is applied we see an exponential growth in the current we know it is connected in forward biasing mode. We then flip the current and we then expect the current to increase only in the region of the breakdown voltage.
So sensor 1804 gave the linear characteristic, confirming to us it is broken and cannot be used to check our electronics.

Voltage vs. Current characteristic for a diode

Cable impedances and noise

Tekst

Notes

RAW notes Martin on SiPMs and impedances