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teamc2024

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Team C - PMT (drafting)

Group members:

  • Mohan Karthik, Tata Inst., IN
  • Nguyen Gia Minh, Fulbright Univ., HCM
  • Ta Van Minh, HUS-VNU, HN
  • Hoang Pham Thanh Dat, HUS-VNU, HCM

Mentor: Dr. Son Cao

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

  • Voltage apply (tested) ~ 14V (range 11.5V to 15.5V)
  • Gain driving (<1V)/ tested 0.9V
  • Peak wavelength sensitivity is around 400nm

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

Details of measurements

  1. PMT/MPPC characteristics, focusing on the noise/ rising time and falling time
    • PMT at different level (but what is the level of single photon)? Can we identify it?
    • For MPPC, noise rate at different threshold (.5PE, 1.5PE, 2.5PE) with different operation voltage 56V, 57V, 58V
      • Due to some electric RF noise, we may want to operate at higher voltage to get more gain, allowing us to set up higher threshold to remove the electric RF noise
    • Rising time and falling time measurement: it's better with LED, to reduce the effect of the electric noise
    • Sensitivity: lower down the light intensity
    • Dynamic range: increasing the light intensity and measure the intensity
  2. Spectra measurement of the white LED
    1. Observe with diffraction grating with high intensity/ take photo with camera (eg. smartphone)
    2. Measure with different LED setting with three setup of optical filter
      1. No filter
      2. FGL400nm
      3. FGL455nm
      4. FGL570nm
  3. Cosmic ray measurement
  • 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?

Important notes

  • 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

Allocated hardwares

Reference

teamc2024.txt · Last modified: 2024/03/05 02:38 by nuicise