Report on the BBC for Run 3

1
Report on the BBC for Run 3

• Interlock System Low Voltage Stuff
• High Voltage Stuff
• Threshold Scan
• Timing Adjustment
• Online Monitoring
• 0th Version Calibration Constants
• 0th Version LUT for the BBLL1

2
Interlock System Low Voltage Stuff

• The Interlock system of the BBC HV had been
  checked
• at the beginning of December.
• When we checked the interlock by temperature, we
  used a (spare)
• potable thermo-couple because it is easy to
  control temperature.
• Once the temperature (thermo-couple) grow up to
  60?C,
• the HV could be disabled.
• Once the air-flow
• (flow-switch) is stopped by
• opening/closing the switch,
• the HV could be disabled.
• All sensors are working.
• Now, NIM bin is powered
• by FEM rack.

3
HV Stuff

• Kohara-kun and I calculated how much HV we
  should apply to
• the BBC, independently. Those are calculated
  from MIPs in run
• 2 and gain curves by the laser data taken in
  the end of Nov.
• http//www.hepl.hiroshima-u.ac.jp/hadron/phx/cons
  tr/kohara/bbc3/BbcConfTableRUN3_05Jan2003.htm
• http//www.hepl.hiroshima-u.ac.jp/hadron/phx/bnl/
  pmt/opv/opv_run3/opv_run3.htm
• Kohara-kun will give a talk about that today.
• The new GUI to control the BBC HV is
• available. It is a Perl/Tk macro and issues
• some hvclient commands
• http//www.phenix.bnl.gov/phenix/WWW/run/03/HV/ind
  ex.html
• (medm system is still available)
• Usage of the GUI is same with medm system.
• Additional features are also implemented.
• All enable/disable button.
• Expert mode to change the HV value manually.
• Load HV values from a file and set all 0
• Write measured/demand value(voltage,current
  etc.).

4
Threshold Scan

• We believed that a conv. factor of digital value
  to threshold is 4.
• But we did not know it was correct. We need to
  confirm it.
• Threshold scan was performed at 1st and 2nd
  access time.
• The method is following
• Input an known change by the external C.I.
• Change the threshold value and measure the cut
  point.
• Conversion factor is estimated as 2.17 and 2.25
• at Test Stand and IR.
• Those are in
• reasonably agreement.

5
Time In (Timing Adjustment)

• Tomoaki could see the PHENIX first collision.
• Center of Timing range is figured out by TP.

6
Online Monitoring

• Tsuchimoto-kun prepared and
• maintain the BBC Online Monitor.
• Checking list is following
• Is overflow shifted?
• Is hit rate correct?
• Are collisions within our
• dynamic range?
• (Gain does not change?)
• All variables are checked
• in PMT by PMT.
• Documentation is available
• http//www.phenix.bnl.gov/WWW/run/03/online_monito
  ring/
• subsystems/bbc/index.html

7
0th Calibration Constants

• 0th version calibration constants are calculated
  by first
• collisions data (100k) taken with ZDC trigger.
  
• Pedestal ADC TDC fact. are determined by
  Qext, Qint and TP.
• Overflow values are calculated by
  Tsuchimoto-kun.
• Slewing factor is calculated by the calibrator.
• Slewing constant is a problem Calculation is
  failed in a few channel.
• It is too low gain. Need to increase HV value.
• Timing resolution is currently 75ps.

8
0th LUT for BBLL1

• Tomoaki and I made 0th version LUT for the
  BBLL1, independently.
• That is based on the constant calculated in
  previous page.
• Global offset is not adjusted yet. (It is
  included in Tomoakis version)
• There are utilities to calculate LUT. I wrote a
  simple documentation.
• https//www.hepl.hiroshima-u.ac.jp/hyperarchive
  /phx-hiro/02/1177.html