Transcript ppt

ISOC/SVAC
Instrument Analysis Meeting, May 26, 2006
New SVAC Ntuple Variables
Anders W. Borgland
Science
Verification,
Analysis and
Calibrations
/
ISOC
Anders W. Borgland
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ISOC/SVAC
Instrument Analysis Meeting, May 26, 2006
New SVAC Ntuple Variables
• Three new groups of variables:
– Context information
– Calibrated ACD quantities
– Error flags
• Updated SVAC Ntuple description:
Anders W. Borgland
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ISOC/SVAC
Instrument Analysis Meeting, May 26, 2006
ACD MIPs
• Calibrated ACD quantities:
– AcdMipsPha[0-603][2]: Calibrated PHA values
– AcdMips[0-603][2]: Calibrated PHA in MIPs
• I also added a few (I hope) helpful variables .....
• Max:
– AcdMipsMax: Maximum calibrated PHA in MIPs
– AcdMipsMaxTileID: Tile ID of maximum calibrated PHA
– AcdMipsMaxPmt: PMT of maximum calibrated PHA
• Sum:
– AcdMipsSum:
– Sum of PHA in MIPs for the whole ACD.
– Average over the two PMTs of each tile
Anders W. Borgland
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ISOC/SVAC
Instrument Analysis Meeting, May 26, 2006
ACD MIPs
Anders W. Borgland
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ISOC/SVAC
Instrument Analysis Meeting, May 26, 2006
Error Flags
TKR FIFO Full
Anders W. Borgland
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ISOC/SVAC
Instrument Analysis Meeting, May 26, 2006
Context Information
• Nearly 40 new variables
• Main categories:
– Extended counters (GEM scalers)
– Time information
............
Anders W. Borgland
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ISOC/SVAC
Instrument Analysis Meeting, May 26, 2006
Thou Shall Learn To Love ULong64_t
• Remember a long time ago?
– We looked at the GEM counters.
• Problem:
– They roll over real fast.
• How to keep track of the rollovers?
– Warren came up with EvtTick using a lot of clever tricks
• With Flight Software:
– JJ does all the work for us!
• Time in system clock ticks (nominally 50 ns):
– Elapsed time
– Live time
• Counters:
– Sequence number ('Event ID')
– Discarded events
– Dead Zone events
– Prescaled events
Anders W. Borgland
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ISOC/SVAC
Instrument Analysis Meeting, May 26, 2006
Extended Counters
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All the extended counters are unsigned 64 bits.
They are NOT reset at the beginning of a run!
Use them to calculate the difference between any two events!
Livetime between any two events i,j:
–
[Livetime(Event-j) – Livetime(Event-i)] / [ElapsedTime(Event-j) - ElapsedTime(Event-i)]
• Known bugs:
– Livetime counter is not always correct:
– Assumed GEM livetime counter was 24 bits and not 25
– Fixed as of Monday in Flight Software
– Affects all the runs taken until Monday!
» And no, will not be fixed by any reprocessing ....
– Synchronization of local copy of the counters in the two EPUs:
– Not always working
– Rollovers may not be taken properly into account
• See Useful things to know about the data quality for further details
and development about these problems.
Anders W. Borgland
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ISOC/SVAC
Instrument Analysis Meeting, May 26, 2006
Time Tones
• We receive a time tone from the GPS every second: 1-PPS
• Can be used to make an event time stamp!
• For every event:
– Information about the current and previous time tone
– Can correct for drift in the system clock i.e. The Tiem Tone is our
absolute time!
• Example:
– Event time stamp in seconds:
Number of seconds since Epoch start 01.01.2001 of last 1-PPS
TimeStamp = ContextLsfTimeTimeToneCurrentSeconds
+ [ ContextLsfTimeTimeTicks / (ContextLsfTimeTimeToneCurrentGemTimeTicks - ContextLsfTimeTimeTonePreviousGemTimeTicks)]
Number of system clock ticks between last two 1-PPS
Number of system clock ticks (50 ns) since last time tone
for this event
Anders W. Borgland
All the ContextLsf....
are SVAC ntuple variables!
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ISOC/SVAC
Instrument Analysis Meeting, May 26, 2006
Time Tones
• Lots of new variables!
• Will take time to learn what they mean and how to use them!
Anders W. Borgland
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ISOC/SVAC
Instrument Analysis Meeting, May 26, 2006
Summary
• All these new variables are available!
– For new data!
– For reprocessed data
• They should make your life a lot easier!
The SVAC ntuple is there for you!
Anders W. Borgland
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