Team C - PMT (to-be-updated)

Group members:

Mentor: Dr. Son Cao

Metal-package PMT module: H6780-1 / backup H10721-110 (newly purchased, using for O-BLM and for other research)

Side note:

One PMT seems more noise than the other
Some issues when powering both PMTs at the sametime? For operating one PMT, with voltage apply of 14.4V, gain control of 0.9, the returned current is 0.03A if using one PMT, and 0.06A if using two PMT

Three main objectives

PMT noise rate, raising, falling; PMT vs. siPM (quantum/detection efficiency, electric gain, linearity, dynamic range)
- Try to make light tightening as much as possible and measure the noise rate (without LED) at different thresholds.
- Use a pulsed optical LED with an optical fiber beam splitter to check the quantum/detection efficiency of PMT vs MPPC. For this you need to lowing down the light intensity as much as possible
- For dynamic range: try to gradually increase the light intensity and check when the signal starts saturated. Be caution to not increase the light amount rapidly
A concept of fast spectrometer: Get spectra of a white light source with optical filter and PMT
- Use white light LED and pulsing it at different voltage/
- Measurement (average acquisition) the signal amplitude with different optical filters (400nm, 455nm and 570nm)
  - Better to use fiber splitter with one signal is used to control the light source stability
Cosmic ray muons measurement (rate, light yield) with plastic scintillator cubes
- Estimate the rate of cosmic ray muon in the cube
- From that estimate the threshold needed for the rate of coincidence
- Check the spread of scintillation light induced by the mostly cosmic-ray muons

Using scintillator cube/ (1) one cube (2) two cube, one to read with PMTs, one to read with MPPC; for MPPC, one can use wavelength shifting fiber
How many photons are collected by MPPC/WLS and how many collected by PMT?

PMT voltage supply <15V and for gain control <1V
MPPC voltage supply <60V
- Some RF noise is induced by this voltage supply. If you are using PMT only, do not turn o this supply.
Light tightening is supper important for PMT (than for MPPC).
Be gentle when dealing with optical fibers
There is some electronic noise induced by other equipment/source in the room
- Estimate the rate
- Check the amplitude signal
- Some methods
  - Put higher threshold, also meaning that you will ignore events with low signal
  - Use light source from LED, you know when the light will come
  - Use coincidence technique when measuring with muons

Oscilloscope Siglent SDS1104X-E
Metal package PMT, model H6780-01
A box with SiPM https://www.hamamatsu.com/content/dam/hamamatsu-photonics/sites/documents/99_SALES_LIBRARY/ssd/s13360_series_kapd1052e.pdf. Students can solder a new one
DC power supplies for PMT and SiPM
Analog Discovery 2
Optical fiber beam splitter Thorlabs TT200R5F1A
Scintillator cube
White LED
Optical filters Thorlabs FGL400, FGL455, FGL570