1. The Effect of Temperature on the Dark Rate of the Silicon Photomultiplier By Jie Zhao Mentor: Dr. Richard Jones

2. What is a Photon Particle of Light Electromagnetic radiation Very small packet of energy –Trillions of Photons in a simple lamp Low intensity light – light that consists of very few photons

3. What is a SiPM Silicon Photomultiplier Solid-state photon detector Detects low intensity photons at around the visible wavelength Uses tiny pieces of individual semiconductors to detect photons

4. The Uses of the SiPM Replacement for the photomultiplier tube (PMT) –Less bulky –Not sensitive to magnetic fields –More detection efficiency Is being actively researched for use in High Energy Particle Physics experiments

5. The Workings of an SiPM Works like mousetrap – only takes a small amount of energy for it to let go –Reverse biased up to breakdown voltage Leaves the SiPM at a metastable state

6. The Workings of an SiPM Any source of energy (such as a photon) would trigger an avalanche At first, a capacitor would be supplying the voltage –After the capacitor runs out of power – a power source would provide the rest of the power through a resister, lowering the voltage After firing, the power source would recharge the capacitor and reset the SiPM for the next firing

7. Dark Rate? The firings of the SiPM are not always caused by light Dark  Rate –The rate at which there are false firings (usually due to thermal energy) of the SiPM, when light is not present

8. Would the SiPM be able to detect single photons? Problem and Hypothesis

9. What is the optimal operating temperature of the SiPM to reduce the dark rate? –Does the SiPM need to cooled during its operation in the actual particle physics experiment? The dark rate of the SiPM will be lower when operating at lower temperatures

10. Review of Literature Collins, Graham. “Making Cold Antimatter.” Scientific American. June 2005. Vergano, Dan. “Tiny neutrinos accelerate a physics debate.” USA Today. Nov. 2001. “What Happened to the Antimatter? Fermilab’s DZero Experiment Finds Clues in Quick-Change Meson” Fermilab Public Affairs. Mar. 22, 2006. B. Aubert et al. “Direct CP Asymmetry in B0 → K+π- Decays”. Cornell University Library. Jul. 20, 2004. Senderovich, Igor and Jones R.T. “Suitability of Silicon Photomultiplier Devices for Readout of a Scintillating Fiber Tagger Hodoscope.” GlueX Technical Note series.. (8 April, 2008). Lolos, George. “Brief Update on SiPM-Array Progress.”. (20 July, 2007). Senderovich, Igor and Jones R.T. “Update on the Suitability of Silicon Photomultiplier Devices for Readout of a Scintillating Fiber Tagger Hodoscope.”. (30 July, 2007).

11. Materials A darkened enclosed box A SiPM array Temperature controller (heat sink) Oscilloscope Light Filters Data Collection Software 3 Power Supplies LED Signal Generator

12. Materials Image from: http://zeus.phys.uconn.edu/wiki/

13. Procedure (Setup) Set up the equipment –Attach the right filter –Close the box to eliminate all possible ambient light –Set the right temperature and allow the heat sink to calibrate

14. Procedure (Setup) Image from: http://zeus.phys.uconn.edu/wiki/

15. Procedure (Data Collection) Set up the data collection mechanism –Turn on and calibrate Oscilloscope –Connect it to the Zeus server –Set Zeus up to collect data at one sample per second Wait a couple of hours for data to collect

16. Procedure (Data Collection) Image from: http://zeus.phys.uconn.edu/wiki/

17. Procedure (Analysis) Load up the data to the Zeus Server Take specific areas of the data set Fit it into a curve Analyze the curve for peaks and noise levels Record Data

18. Procedure (Analysis) Image from: http://zeus.phys.uconn.edu/wiki/

19. Results (Detect Single Photons) The integral was taken of the energy for every peak Each measurement was then divided by the average energy per pixel on the SiPM A histogram was made of the data

20. Results

21. Results (Dark Rate) Take the integral of the data when there is no pulse Find the average dark rate of the SiPM at the selected temperature

22. Results (Dark Rate)

23. Discussion (Detect Single Photons) Image from: http://zeus.phys.uconn.edu/wiki/

24. Discussion (Detect Single Photons) Problem – Can we see individual photons? The data strongly suggests that single photons can be reliably detected by the SiPM

25. Discussion (Dark Rate) Image from: http://zeus.phys.uconn.edu/wiki/

26. Discussion (Dark Rate) The dark rate of the SiPM will be lower when operating at lower temperatures The data supports the hypothesis that lower temperatures entail lower dark rates

27. Conclusion The SiPM seems to be a viable alternative to the Photomultiplier tube in High Energy Physics Experiments If the change is made, physicists must monitor the temperatures of the SiPM as it is a large factor in determining its dark rate