Production PMT Testing and Work on Site with Prototype Tank University of California, Los Angles Department of Physics and Astronomy Chris Jillings November, 2000

 Production PMT testing 1.Requirements 2.Light source 3.Electronics and DAQ  Prototype tank (Sept 2000)  Low gain or high gain Talk Outline

 Production PMT test system in push-button operation  Detailed understanding of energy calibration of individual tanks in engineering array  Using this to understand energy cal of showers  Regular contributions to site In One Year…

 48 PMTs in one day  Measure 1.Linearity 2.Gain / Dark rate vs voltage 3.Pulse shape 4.Afterpulsing Production PMT Testing

The Lab in the STRB

Schematic

Overview

 Need 1% stability for linearity  Timing on 25 ns scale  Wide range of brightness Light Source Blue LED

 TTL logic to control two LEDs in each source  Analog line to control brightness  Counter/timer to trigger source  PCI 6025E from Nat. Inst.  Small amount of custom TTL circuitry Light Source Our current triggering circuit will work

High Voltage  Standard system (CAEN SY403)  HV supply on the base  Needs 5V for power  Analog level to control HV

 Disc. for noise rate  Two ADC’s per PMT 1.Auger has 15 bits dynamic range 2.Commercial ADC has 10 to 12  Multiplexing for PMT signal digitization CAMAC/NIM System

 Either 1.Digital scope with GPIB 2.PCI card with 100 MHz digitizer  Both require multiplexing Pulse Shape

 Automated analysis 1.Yes/no/maybe? 2.Linearity curve 3.Gain/Dark Rate vs HV 4.Pulse shapes  Archive plots and complete data tables using HTML interface  Root macros to read data Analysis and Archiving

On-Site Work Clear sky High elevation Plateau Fluorescence detector September 2000

On-Site Progress

On-Site Goals  Test over-wintered tank  Number of pe per muon  Learn electronics/DAQ  Requirements for PMT tests  Contribute to site

Prototype Tank

Muons in Tank PMT 1PMT 2 PMT 3 10 mV per division 100 ns per division

Muons in Tank Gain = 10 6

Average Muon Pulse 12 m atten length

 Low Gain (10 5 ) 1.Amplify last dynode for small signals 2.Use anode for large signals  High Gain (10 6 ) 1.Anode for small signals 2.Deep dynode for large signals Gain???

Back at UCLA…  Tap dynode 8 of 12 of ETL PMT  The signals look beautiful Deep Dynode Tap

Linearity Still Not There

 Run at about 2  10 5 gain  PMT test stand designed  PMT test stand to be built  Contribution to site  Energy calibration Conclusions