PMT Evaluation and Testing
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PMT Evaluation and Testing • Evaluation • Characterization • Production testing (won’t include water/pressure tests here, or radioactivity)
description
PMT Evaluation and Testing. Evaluation Characterization Production testing. (won’t include water/pressure tests here, or radioactivity). Goals--Evaluation. We want to p ick a PMT that: . Optimizes #identified photons/$ Has timing `good enough’ to do experiment Has low failure rate - PowerPoint PPT Presentation
Transcript of PMT Evaluation and Testing
PMT Evaluation and Testing
• Evaluation• Characterization• Production testing
(won’t include water/pressure tests here, or radioactivity)
Goals--EvaluationWe want to pick a PMT that:
1. Optimizes #identified photons/$2. Has timing `good enough’ to do experiment3. Has low failure rate4. Has good overall stability
Goals--Evaluation1. Optimizes #identified photons/$
#identified depends on:• Overall coverage (inc. reflectors/wavelength shifters)• QE (including magnetic field effects)• Ability to resolve multiple hits via Q or T• Noise rate
Goals--Evaluation1. Optimizes #identified photons/$
R5912-02R1408
Resolution with charge better on left
Goals--Evaluation1. Optimizes #identified photons/$
R5912-02 R1408
Resolution with time better on right
Goals--Evaluation1. Optimize #identified photons/$
Extra collection vs. stability
Goals--Evaluation1. Optimizes #identified photons/$
50,000 PMTsDt = 180 nsRpmt = 1000 Hz Effects of PMT
noise rates on trigger
Goals--Evaluation
2. Has timing `good enough’ to do experiment
Evaluation PlanS4 requested 10x4types of PMTs for evaluation in Year 1Then 50 of selected type in Year 2Project naturally divides into two classes (not counting pressure or radioactivity tests):
R&D: concentrators/reflectors
wavelength shifter magnetic compensation bases
Strict evaluation: Relative Q.E. Charge spectrum Timing Noise Stability
Evaluation Plan
Plenty of places to do testing:
DavisBrookhavenWisconsinPennDrexel…(nearly every institution here)
We should reproduce critical measurements at more than one place…but not at every place.
We also need simulation input (How many pe do we need?)
Evaluation Plan
As of S4:• PMTs arrive at Penn, bases added• Small number of simple measurements made, shipped to other institutions
Brookhaven for magnetic field/temperature tests Davis for magnetic field tests and wavelength-shifter tests Drexel for single-pe charge tests and concentrator
development Penn for single-pe charge and timing studies, and q.e. Wisconsin for gain stability, q.e., charge and timing, water
tests …
Evaluation Plan
As of S4:• Need database of results on critical numbers/plots
Noise rates Gain vs. HV Q.E. Timing and charge spectra Magnetic compensation effects
• Decision on PMT in Year 1 (is this wise?) Critical to have simulation input in context of
physics goals and priorities
Goals--CharacterizationWant model inputs from PMT measurements---Most important for low E program• angular and wavelength dependence of response• Detailed timing and charge spectra at 1 pe and above• Long term stability and behavior• Gain vs. HV (compare to manufacturer)• Noise variations• Studies on full optical modules (in water)• Develop production testing plan
Characterization PlanWant one (or two) institutions to do bulk of measurements
• Database of PMT data• Translation into simulation model inputs• Apparatus and plan for production testing
Production Testing
• Reject non-working PMTs• Reject PMTs outside of spec • Gain matching
Testing 100 PMTs/day ~ 5 years…
Depending on timing, testing in-situ may be most sensible approach
Conclusions
• Evaluation of PMTs relatively simple, but will involve several institutions focusing on different areas
• Should divide activities by resources and interest
• Characterization plan will be defined by physics needs and what we learn during evaluation
• Production testing is a bigger challenge and needs some thought
