How to Collect Beam-Gas Data for FNC
The Forward Neutron Calorimeter needs beam-gas data for
calibration purposes.
These events should be taken with stable proton beam at 920 GeV and
preferably without electron beam.
To collect the data, do the following:
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Switch on FNC HV: On A3-Top or B15-Left PC select
"Forward Systems HV" window, click on FNC icon, select "LUMI"
in "HERA status" drop-down list and then click on "ON" near "Full HV".
Wait until FNC HV Status reached "HV full" state (green).
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In SSP "Readout and Data Logging" panel: include in readout
only "Central Trigger" and "Subsystem 101" branches, in subsystem 101
enable only FNC subbranch. Disable "Level 3" option.
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In SSP "Trigger" panel: choose "Test and Calibration".
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In SSP: set all Trigger panels (General,Trigger1-4,L2) to "$00000000".
Then enable subtriggers s120 and s123.
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Confirm all changes and start the run.
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On CTrig Mac: open "Subtrigger rates and prescales" window and
set a prescale for subtrigger s120 so that the s120 rate after prescale
(L2 input) is approximately equal to 100 Hz. (divide s120 raw rate
by 100 to obtain needed prescale factor).
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Switch to "Permanent Data Logging", confirm all changes and start new run.
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Stop the run after 20 minutes or after 100K events have been collected.
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Write down run number to the H1Logbook.
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Switch FNC HV to Standby: on FNC HV panel select "INJECTION" in "HERA status"
drop-down list and then click on "ON" near "Standby HV".
-
Restore SSP parameters back to standard.
Last modified: 15.01.2007 by Vitaliy Dodonov