SiPM Research & Development

Teacher: Mark Kirzeder

Student: Emily Lohr

Advisors: Dr. Randi Ruchti

Mr. Barry Bambaugh

Silicon Photo Multiplier A new generation of detection system.

An alternative to traditional PMTs.

What is a SiPM?

SiPMs vs. PMTs Small Low voltage Relatively low cost Recoverability Signal consistency Unaffected by B field Single photon

counting ability Fast response time

Relatively Large High voltage Expensive Non-recoverable Inconsistent signals Affected by B fields Not as precise Slower response time

SiPM Signals

Individual photon counting ability Active area Inactive area

SiPM Drawbacks

Optical cross talk A signal from one pixel generates a signal

in an adjacent pixel High rates of noise

Objectives Quantify SiPM performance with respect

to Manufacturer: Sensl vs. Hamamatsu Number of pixels (active area) Size: 1mm (square) vs. 3mm (square) Bias Voltage Temperature

Determine best configuration for SiPM operation

Experimental Set Up

Experimental Devices

Hamamatsu device with

electronics for controlling bias

voltage

Sensl device with electronics for cooling and controlling bias voltage

Experimental Devices Sensl – Major Focus

1mm x 1mm square 35 micron x 35 micron square pixels

3mm x 3mm square 35 micron x 35 micron square pixels

Hamamatsu – Minor Focus 1mm x 1mm square

25 micron x 25 micron (1600 total pixels) 50 micron x 50 micron (400 total pixels)

Experimental Set Up SiPM Location Light Splitter

For future use when operating 2 SiPMs simultaneously

LED Red Pulsed at 50 kcps

Noise Study - Methods

SiPM turned on in the box without the LED

A counter was used to determine number of events that were above a given threshold

Temperatures were tested from +25 oC to -30 oC

Bias voltages were tested from 29.5V 31.5V

Noise & Temp Study – Sensl Results

Red = 29.5V, Orange = 30.0V, Yellow = 30.5V, Green = 31.0V, and Purple = 31.5V

Noise & Bias Study – Sensl Results

Red = +25C, Orange = +20C, Yellow = +10C, Green = 0C, L. Blue = -20C, D. Blue = -25C, and Purple = -30C

Noise & Bias Study – Hamamatsu Results

Red = Ham Electronics, Yellow = 30ns gate, Green = 100ns Gate and Blue = 100ns Gate

Conclusions 3mm Sensl Device

Noise was minimized at -20 oC A bias of 30.0 V allows for greatest

reduction of noise at -20 oC 1mm Sensl Device

Noise continued to decrease slightly at -25 oC and -30 oC, although it seems to plateau

A bias of 29.5 V allows for greatest reduction of noise at -30 oC

Signal Quality Study - Methods LED was used as the trigger Signals were read into a QVT from the

SiPM Data was then analyzed using a program

developed by Barry Bambaugh according to a Poisson Distribution Identified number of events Calculated the mean number of photons,

peak separation, and number of peaks.

Signal Quality Study - Methods

A desirable signal is one that has Large average number of photons Large peak separation Large number of peaks Low amount of noise

Signal Quality Study – Results:Average Number of Photons

Red = +25C, Orange = +20C, Yellow = +10C, Green = 0C, L. Blue = -10C, D. Blue = -20C, L. Purple = -25C, and D. Purple = -30C

Signal Quality Study – Results:Average Number of Photons

Red = 29.5V, Orange = 30.0V, Yellow = 30.5V, Green = 31.0V, and Blue = 31.5V

Conclusions 3mm Sensl Device

Little difference in photon detection (+/- 0.2) efficiency at all temperatures at 30.0V

Peak separation increases with increased bias

1mm Sensl Device Most photons detected at -10 oC Peak separation increases with increased

bias

Future Work

Exact operational conditions will depend on the application of the SiPM Noise can be reduce drastically with temp Efficiency can be increased with bias

Bias does affect noise

Operate two SiPMs simultaneously to verify that the LED is unchanged

Experiment with the Hamamatsu devices more thoroughly