Background Sensors and Monitoring
PEP-II Liaison Training
31 March 1999
Why do we need the background
Background Tuning: we need to
measure backgrounds after injection and use the
monitoring devices to tune backgrounds to acceptable level
before bringing BaBar fully online.
Background Monitoring: we need to
measure backgrounds on various time scales to determine if we
are, e.g., too high at this minute for useful data; too high on
average this day/week/month to sustain this dose rate to the
SVT, EMC, DCH.
Background experiments: we need
independent monitors available during dedicated background
running when sensitive sections of BaBar may be off.
The background sensors for BaBar
- PIN Diodes
- Stanford, SLAC
- 12 PIN diodes
- continuously read out via analog abort modules
- continuously read out via SVTRAD abort modules
- raw currents (damage, dose rates, temps) sampled at
fast and slow (7.5Hz) rates (via EPICS)
- monitor each interlock channel for time to trip
- David Kirkby et al.
- 12 Layer-1 half detector modules
- leakage currents monitored via CAEN supplies when
detector is biased (during data taking only) via
CAENnet interface to EPICS
- 12x14 Layer-1 AToM chips
- per strip occupancies accumulated in ROM's and
available in real time, via TCP/IP into EPICS
- parameters sensitive to accumulated radiation
damage extracted from each threshold-scan
calibration and archived in conditions database
- occupancies in depleted mode?
- Aaron Roodman, et al.
- long term radiation dose monitoring at electronics via
RADFET's (into EPICS)
- 4 PIN diodes (probably with small CsI button to increase
sensitivity) ganged together with output via analog abort
module to MCC
- current drawn by each power supply monitored via CAEN/EPICS
(will regang power supply cables to increase
maximum current draw to 80uAmps); need to determine a
"tuning" voltage where current is sensitive enough to bkg
so currents can be used during beam tuning
- DCH occupancy
- @safe HV => for tuning, requires some change
to e.g., runnable state definition
- @full HV => for monitoring during data running
- Bob Wilson, Guy Wormser, Georges Vasileiadis, et al.
- single discriminated PMT's per DFB ==> 2 per sector
- rate from one PMT will go into FVC and sent via SAM to MCC
- rate from one PMT per sector into gated scaler via EPICS
- power supply current draw for 16 PMT groups via CAEN/EPICS
- Adrian McKemey et al.
- long term radiation dose monitoring via RADFET's (EPICS)
- ganged diode dark currents via CAEN/EPICS
- 8 quadrants in barrel
- 2 halves in endcap
- 4 PIN diodes with small CsI button to increase
sensitivity ganged together via RADMON-like module;
output via analog abort module to MCC
- Henry Band, Jim Johnson, Pigi Paolucci
- current draw via CAEN/EPICS (but temp effects probably
- 2 1m**2 RPC's (back/forward) with 2 FEcards each going to
4 scaler channels; monitor with 2s integration time via EPICS
There is a
table of signals showing which tasks they address (Bkg tuning,
monitoring or for experiments).
There is a
table of signals showing whether they are hardwired analog
signals or via EPICS variables, along with readiness state.
There is a
table of EPICS signal names. Most detectors are still working on
the final epics code and names.
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This page is maintained by Terry Geld
Last modified: Tue Apr 13 14:06:03 PDT 1999