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Results from the PMT test bench in BCN (10-Oct-03). J.Garra, R.Graciani, E.Graugés, X.Xirgu. 8 stage PMT. CFD base: The output of 1 channel studied to perform a premilinary analysis on: Signal Shape Gain Number of photo-electrons. CFD active base. Signal Shape.
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Results from the PMT test bench in BCN (10-Oct-03) J.Garra, R.Graciani, E.Graugés, X.Xirgu
8 stage PMT • CFD base: • The output of 1 channel studied to perform a premilinary analysis on: • Signal Shape • Gain • Number of photo-electrons
Signal Shape • Some oscillations in the signal shape are supposed to be caused by some connection(?) problem.
Gain vs Photo-Statistics • Possible saturation effects might be observed starting around 50 phe and above
Gain • Our desired HV working point should be ~ 600 Volts obtaining an approximate gain of 30k to 50k
8 stage PMT • BCN base: • A preliminary study has been performed with a LED source (no fibre) • Gain and Photo-statistics have been looked at from the output of a 1 channel (#64) • Now the setup is ready to get measurements for all the channels at once. • Fatal accident ended up with the 8-stage PMT becoming unusable anymore
The oscillations present in the first attempt (CFD) could be partially removed (with the BCN base) by when the setup has been re-done very carefully and assuring a common grounding for the (ADC/Black Box/Active Base) system. • Still to be tried if that also cured the oscillation observed using the CFD base
12 stage PMT • This PMT has already incorporated the active base by Hamamatsu together with the (PMT/Base) system encapsulation • Scans of 50x50 measurements each have been performed for different angles to ensure the geometrical consistency of the setup (PMT plane parallel to the fiber scaning plane): 0,90,180 and 360 deg. scans • Also scans with different light intensities have been taken to test the uniformity in the linear response of each channel.
2D Scans • Different angles • Different light I
To do list • Let the new team get more experienced • Complete a final version of the fine scans (Motor lost steps, etc…). • Understand any the level of saturation of the signal • Single photo-electron measurement using a 2-stage amplifier board (work in progress)