1,004
edits
Changes
Jump to navigation
Jump to search
Line 32:
Line 32: − + + +
→Bench Test Setup
= Bench Test Setup =
= Bench Test Setup =
A fast light source operating in an environment with little background is necessary for the tests described here. The challenge is in preventing light leaks in this chamber despite the need for access ports, patching wires through walls and installing sensor and temperature control modules that must interface with the outside.
A fast light source operating in an environment with little background is necessary for the tests described here. The challenge is in preventing light leaks in this chamber despite the need for access ports, cable feed-through, and a temperature control module that requires heat exchange with the outside.
A [[dark chamber]] was constructed to create this controlled environment. Please refer to the [[dark chamber | more detailed page]] on its construction, test and calibration.
A [[dark chamber]] was constructed to create this controlled environment. Please refer to the [[dark chamber | more detailed page]] on its construction, test and calibration.
Additionally a reference sensor is necessary to calibrate the light flux. A UV/Blue/Green-sensitive [[Hybrid Photodiode]] (HPD) from DEP was used for this purpose. It has a detection efficiency of 5-15% in the wavelength range of our light sources and a factor of 2700 gain at the recommended HV of 12 kV. Unfortunately this low gain and its high capacitance (~200 pF) results in statistical charge fluctuations of several photo-electrons, preventing discrete photon counting. However, devices of this type, owing to their simple acceleration gap, have a very predictable gain, consistent from from one unit to the next. Its gain factor was used as an assumption for all subsequent calculations.
= SiPM Measurements =
= SiPM Measurements =