PMT Evaluation and Testing

1. PMT Evaluation and Testing • Evaluation • Characterization • Production testing (won’t include water/pressure tests here, or radioactivity)

2. Goals--Evaluation We want to pick a PMT that: Optimizes #identified photons/$ Has timing `good enough’ to do experiment Has low failure rate Has good overall stability

3. Goals--Evaluation 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

4. Goals--Evaluation Optimizes #identified photons/$ R1408 R5912-02 Resolution with charge better on left

5. Goals--Evaluation Optimizes #identified photons/$ R5912-02 R1408 Resolution with time better on right

6. Goals--Evaluation Optimize #identified photons/$ Extra collection vs. stability

7. Goals--Evaluation Optimizes #identified photons/$ 50,000 PMTs Dt = 180 ns Rpmt = 1000 Hz Effects of PMT noise rates on trigger

8. Goals--Evaluation 2. Has timing `good enough’ to do experiment

9. Evaluation Plan S4 requested 10x4types of PMTs for evaluation in Year 1 Then 50 of selected type in Year 2 Project 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

10. Evaluation Plan Plenty of places to do testing: Davis Brookhaven Wisconsin Penn Drexel …(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?)

11. 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 • …

12. 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

13. Goals--Characterization Want 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

14. Characterization Plan Want one (or two) institutions to do bulk of measurements • Database of PMT data • Translation into simulation model inputs • Apparatus and plan for production testing

15. 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

16. 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