1. WBS 2.5 HF PMT SYSTEM Y. Onel University of Iowa US CMS DOE/NSF Review May8-10, 2001

2. Outline HF PMT Specifications Previous Experimental Data on Photodetectors by HF Group Tasks of the Test System: Procedures for measurements Quality Assurance HF PMT Test Station Preliminary HF-PMT Candidate Tests/Specs Experimental Data Manpower and expert team to install the test system Vendors Milestones Conclusions

3. HF-PMT Specifications Summary Window MaterialBorosilicate glass Effective photocathode dia22 - 28 mm, head-on >15 % 400-500 nm Photocathode lifetime> 200 mC Anode current vs position< +/- 20 % with 3 mm spot scan Gain10 4 to 10 5, 10 5 at < 0.75 x VKA(max) Single pe resolutionrms/mean of single pe peak 50 % or better Pulse linearity+/- 2 % for 1-3000 photoelectrons Anode pulse rise-time< 5 ns Transit time< 25 ns preferred Transit time spread< 2 ns preferred Pulse width< 15 ns FWHM Gain (1/2)-lifetime> 1500 C Average current IK< 1 nA ( g = 104 ) Average current IA< 10 mA ( g = 104 ) Anode dark current< 2 nA ( g = 104 ) Stability< +/- 3 % within any 48 hr. period Envelopeopaque and –HV conductive coating

4. Previous Experimental Data on Photodetectors by HF Group R6427

5. PMT Measurements (*= vendor measurements in PR) 1.*quantum efficency 2.*dark current 3.*gain at 5x10 5 V 4.*pulse-height resolution at 5 x 10 4 V (100 pe) 5.Gain vs. high-voltage 6.Linearity and pulse-rate dependence (4:1 method) 7.Rise-time and transit-time 8.Current vs. photocathode spot position (xy scan) 9.Anode sensitivity vs. wavelength (dye laser) Light source: laser diode, 2 ns rise and fall, 100 MHz dye laser

7. Doses at PMTs (10 Years)

8. Energy spectra of gammas and neutrons in the locations of PMTs, fiber bundles and electronics (FLUKA) GammasNeutrons

9. PMT Window Radiation Damage

10. FLUKA Calculations Recent radiation background simulations show improvement in the design of the shielding around the PMT region by a factor of ~two. The new results are: All neutrons2.54x10 12 Neutrons (E>100KeV)1.63x10 12 Neutrons (E>20MeV)5.12X10 11 Ch. Hadrons2.26x10 10 Muons4.65x10 9 Photons1.53x10 12 Dose7 krad

11. Tasks of the PMT Test System: HF PMT Quality Control and Test System will address the following items: label and catalogue each PMT at delivery and storage; mechanical assembly with HV power supply and base; installation in Test Boxes : individually or in groups;

12. Procedures for measurements The following sequence of measurements will be performed for each PMT or each PMT batch: 1 - PMT's installed in Test-Box are let to stabilize at standard HV; [each tube] 2 - Check of normal operating conditions [each tube] 3 - Noise and dark current measurements vs. HV; [each tube] 4 - Gain vs. HV [laser]; [each tube] 5 - Single photoelectron level; [each tube] 6 - Linearity for 1- 3000 p.e.; [each tube] 7 - Rate dependence for 0.1 - 40 MHz [LED]; [each tube] 8 - Photocathode uniformity; [for each batch] 9 - Quantum efficiency (300-600 nm) [dye laser]; [for each batch] 10 - Pulse shape measurements at nominal HV. [for each batch] According to specifications of the PMT (manufacturer's data sheet and preliminary measurements on a test sample) and requirements of HF application (Nphe/GeV, dynamic range, etc.) the test setup working conditions will be adjusted in a range of light yield and sensitivity appropriate for the standard test procedure. Three light sources will be used for the specific measurements: - laser - LED - Rad. sources + radiator

13. Measurements will be performed at stable (controlled) temperature using defined procedures for each PMT or each PMT batch. Light sources will be installed (Tungsten Lamp, Laser, Dye Laser, Laser Diodes) for the specific measurements The data for each PMT will be stored in appropriate archive files on disk and copied to permanent storage media. For each PMT an entry will be printed and logged to a general PMT directory and test logbooks. The PMT's conforming to acceptance criteria, will be sorted in classes and stored. Those not conforming will be returned to the manufacturer. All measurement procedures will be automated and computer-controlled, to minimize individual biases and interventions; daily test shifts will be supervised by an expert, who will also review the archived data of the day and certify their validity. The fully automated PMT Test station will contain (x-y scanners, neutral density filter wheels [computer controlled], optical bench, DAQ [LabView] and interface systems.)

14. Quality Assurance At the manufacturer testing/preselection as they arrive beam/calibration tests during the installation period PMT can be replaced

15. Tests required of the vendor on each tube 1.Measure and report the quantum efficiency of the tube at 420nm. 2. Determine the voltage at which a current gain of 5x10 4 is reached. Measure the dark current at a current gain of 5x10 4.

16. Additional tests The vendor shall determine the pulse height resolution at a gain of 5x10 4 using the following method or some other method agreed on between us and vendor. The PMT pulse height resolution shall deviate less then 50% from the ideal resolution (defined as sigma/mean equal to 1/sqrt(t) where Npe is the average number of photoelectrons produced by the photocathode for a given light pulse intensity) at a current gain of 5x10 4. The vendor and University shall agree on an appropriate test to determine that this resolution specification is met.

17. HF PMT Test Station CAMAC ADC PC scs i GATEPULSAR LASER DIODE VARIABLE ND FILTER 0-3mm 635 nm CW base PMT Nano- ammeter IEEE 488 Scope Calib Power Meter ND Filter sync trig sync trig W/ double 4:1 option x-y stage gate D8D8 A

18. Preliminary HF-PMT Candidate Tests/Specs Measurements 1.Anode Dark Current 2.Leading Edge Rise Time 3.Pulse Width 4.Transit Time 5.Transit Time – Spread 6.Current Gain 7.Linearity

19. Pulse Setup

20. Gain-QE Setup

21. Neutral Density Filter Setup

22. Photodetector Linearity Measurements

23. Scope View

24. Transit Time, Rise Time, Pulse Width

25. Gain & Dark Current Gain Dark Current

26. Manpower and expert team to install the test system UI U. Akgun (DAQ, Pulse Setup) A. Ayan (DAQ, Pulse Setup) P. Bruecken (Dye Laser System, Pulse Setup) M. Miller (LED System, Optical Installation, Electronics) Y. Onel (Project Manager, Procurement, Specs) I. Schmidt (Mechanical Installations, Electronics, Gain Setup) Post-doc (TBN) (Test Facility Manager) ISU W. Anderson (DAQ, Specs) Fairfield U D. Winn (Gain Setup, Specs) International Team I. Dumanoglu Turkey (DAQ) E. Gulmez Turkey (Electronics, Trigger)

27. Vendors Hamamatsu Corp Burle Industries Electron Tube Int (EMI) Photonis (phillips) ADIT

28. Milestones Draft RFPMarch.15.01 Evaluate samplesMay.15.01 PMT test station readyAugust.15.01 Final contract signed September.15.01 Delivery 1 st batch 100 PMTSNovember.1.01 Delivery last batchJanuary.1.03 *Assuming delivery of 200-300 PMT’s after 3 months of receiving order. Then delivery 200-300 PMT’s per month as last batch delivered by January 1, 2003. *We budget total of 1 hour to unpack, test, label, repack, and enter, merge publish & archive data 2700 PMT. The selection database will be maintained for each PMT together with the base and front end electronics.

29. HF Radiation Environment Recent radiation background simulations show improvement in the design of the shielding around the PMT region by a factor of ~two. There is no issue with the radiation dose or neutron flux where the PMTs are located. All neturons2.54x10 12 Neutrons (E>100KeV) 1.63x10 12 Neutrons (E>20 MeV) 5.12x10 11 Ch. Hadrons2.26x10 10 Muons4.65x10 9 Photons1.53x10 12 Dose7 krad

30. Other Issues Scintillation of the PMT window is only a concern if the dose rate is >0.03 rad/sec. For HF, the estimate is 0.00002 rad/sec (factor of 1000 less). Ambient He partial pressure in air (0.53 Pa) will not be a problem with borosilicate window. Partial pressure will change 10 times in 10 years but will remain below the danger level by a factor of ~50000. Nitrogen gas will be circulated inside the ROBox against He leak from cryogenics and temperature fluctuations (+/- 2 degrees should not be a problem).

31. PMT Manufactures Contacted and Candidates HammamatsuR7525 Electron TubeD843WSBD844WSB PhotonisXP2960XP3182 Burleno response ADITno response Melzno response

32. HF PMT Quantum Eff. >15 % 400-500 nm QP Fiber 54 Mrad Dose

33. Tube Base Prototype completed end of January –Cockroft-Walton multiplier style base –Series resonant sine-wave converter invented by Claudio Rivetta and implemented by Sten Hansen (Fermilab) Very low noise Low power consumption –Last dynode voltage sags 0.5 V from 0 to 200 microamps – factor of 20 headroom for the hottest tubes at eta = 5 –Iowa State and Texas Tech Universities responsible for specifications and testing

34. Tube Base Prototype

35. Tube Base Schematic

36. Specifications - Reprise Window materialborosilicate glass Effective photocathode dia.22 - 28 mm, head-on >15% 400-500 nm Gain10 4 to 10 5, 10 5 at < 0.75 x V KA (max) Anode current vs. position< +/- 20 % with 3 mm spot scan Single pe resolutionrms/mean of single pe peak 50% or better Pulse linearity+/- 2% for 1-3000 photoelectrons ( g = 4x10 4 ) Anode pulse rise-time< 5 ns Anode pulse width< 15 ns FWHM Transit time< 25 ns preferred Transit time spread< 2 ns preferred Gain recovery after 2000 pe pulse within 10% of nominal ( g = 10 4 ) in 25 nsec Average current I K < 1 nA ( g = 10 4 ) Average current I A < 10  A ( g = 10 4 ) Anode dark current< 2 nA ( g = 10 4 ) Photocathode lifetime> 200 mC Gain (1/2)-lifetime> 1500 C Stability< +/- 3% within any 48 hr. period Envelopeopaque and –HV conductive coating

37. Procurement/Testing Strategy Hamamatsu, for example, will deliver 200 PMTs/month. We need ~14.3 months. PMTs will be supplied with gain of 3x10 5 with gain measurements at 1300, 1500 and 1650 V by Hamamatsu. The cost estimate is 690 K$ based on 110 Yen/$. Sole source or bidding? There are several PMTs that would do the job. We should be able to test at the same rate as production, i.e. 10 PMTs/day, on average. The PMT responsibilities are with Iowa, ISU and Fairfield.

38. Lifetime - II 2300 C (~25%) 807 C (~12%) 192 C (~3%) 183 C 175 C 157 C 84 C 12 C These estimates are based on 0.25 pe/GeV and gain of 1x10 5 for one calendar year. Assuming that the acceptable PMT criterion is 50% performance of its original, we would replace 36 PMTs the second year (Ring 1 EM), 72 in the fourth year (Ring 2 EM and Ring 1 HAD), etc. It is probably a good idea to secure these PMTs ahead of time with the rest of the PMTs (Appox. 150). There does not seem to be a drastic problem with PMT aging based on what we know now. The gain loss may be recoverable by voltage increase.

39. PMT Measurements 1.*Quantum Efficency 2.*Dark Current ** 3.* Gain ** 4.*pulse height resolution 5.Gain vs. High Voltage ** 6.Linearity and pulse-rate dependance ** 7.Rise-time ** 8.Transit-time ** 9.Transit time spread ** 10.Pulse width ** 11.Current vs. Photocathode spot position 12.Anode sensitivity vs wave length * Vendor measurements ** Iowa measurements on the candidate tubes

40. Conclusions We had PRR at CERN in Feburary We have evaluated the performance of the candidate PMTs RFP is drafted and we expect to sign the final contract in early September We have designed the PMT test station and built a small prototype version to evaluate the candidate PMTs. Computer controlled x-y scanner and neutral density fibers are built and presently under test Major components of the final PMT station and related electronics are purchased and the system will be ready by mid-August Design of CW bases are in progress at FNAL The PMT readout project is on time and budget