E949 Range Stack Monitoring System Testing

• The first system integrations tests took place in 1-216 on November 22-27, 2000. Two reference PMT's were in the temperature control box, each viewing one fiber bundle and one YAlO source. One fiber from each bundle also illuminated an RS PMT in a separate black box. The temperature of the LED driver box, the voltage of the LED driver source and the HV of the Ref PMT's were all monitored in a scanning ADC. The output of the two reference PMT's and the two RS PMT's were monitored in an LRS2248 ADC.
  • Some distributions : the pedestal width is quite narrow, The YAlO's are providing ~800 p.e., The LED is providing ~2000 p.e. to the Ref PMT's and ~750 p.e. to the RS PMT's.
  • Stability over time for LED and YAlO. The jump of RS1 at 50 hours was traced to a light leak in the RS box, which was taped over.
  • Stability over time for temperature and voltages.
  • Normalizing to the Ref PMT is not so good, due to instabilities in the YAlO.
  • Stability vs. temperature: 0-10 hours LED = 10 C, Ref = 25 C; 11-20 hours LED = 25 C, Ref = 25C; 21-28 hours LED = 25 C, Ref = 10 C.
    • LED on Ref and RS and YAlO on Ref .
    • temperature and voltages .
    • LED on RS and Ref (with normalization) .
  • Stability for the last 4.5 days (Comments on plots from Tadashi) :
    • LED on Ref and RS and YAlO on Ref .
    • temperature and voltages .
    • Pedestals for Ref and RS PMTs .

  Only one thermocuple was available, so the temperature of the Ref PMT and RS PMT boxes were not monitored. The voltage outputs of the temperature control boxes are not connected (Tadashi will enquire about an after-the-fact upgrade.), this means that we do need thermocoupels in each box. Conclusions:

  • The light outputs to the reference and RS PMTs are about as expected.
  • The 16-bit scanning ADC (JOR1616) and temperature box were both stable at ~0.1 C.
  • The YAlO light output showed large variations compared to all other parts of the system.
  • The HV is anti-correlated witht he YAlO output, but not the LED output
  • The LED output on RS2 was more stable than on the Reference PMTs,
  • The LED and YAlO output on Ref1 and the LED output on Ref2 all declined by ~1-2% over 3 days, but the YAlO output on Ref2 did not. The driver voltage increase by 10mV over this time.
  • The LED driver voltage has an anti-correlation with temperature; which is the same direction as the driver circuit itself.
  The next set of tests will include all 12 Reference PMTs; a new reference PMT HV distribution and monitoring system; additional thermocouples; the full RS/BV/BVL which is hopefully light-tight.

• The next set of tests took place at the E949 detector from January 18, 2001 - Feb. xx, 2001. One spare bundle was connected to the boxes on top of the magnet and a dark box with one RS PMT. (The EC Xe cables were used between the apparatus on top of the magnet and the DAQ system, which was the same system as used in the earlier tests but moved to the counting house).
  • First 40 hours
    • This test has started out somewhat more promising. It appears that we can see 1% gain changes in the RS PMT.
    • RS PMT and Ref PMT
    • Stability of inputs
  • First week.
    • LED, YAlO and pedestal peaks
    • RS PMT and Ref PMT
    • Stability of inputs
    • Counting house temperature

• The next work during Feb 20-27, 2001, included tests of 12/15 reference PMTs with the test LED and fiber bundle, and tests of the full driver circuit/LED/bundle for all 8 RS and 4 BVs with one the test Ref PMT (from January tests). The trigger circuit setup has begun.
  • Final data from first two weeks of January test
    • LED, YAlO and pedestal peaks
    • RS PMT and Ref PMT
    • Stability of inputs
    Feb. tests
    • Test of each LED circuit with test Ref PMT
    • Test of each Ref PMT with test LED

• The next set of tests will occur during March, 2001 and will include the full configuration, with RS HV on.

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