Transcript QIE Boards - Indico

Validation and Analyzing of
Front End Readout Electronics
(QIE boards) Data
Irina Shreyber, ITEP
RDMS Workshop 12 March 2009
Outline
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Short “introduction”
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QIE Data we have in the Data Base
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Checked results, missed results, updated results
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Summary
QIE Boards
• The CMS experiment is designed to run with a beam crossing
time of 25ns or at 40 MHz. The front-end electronics must
digitize analog signals from Hybrid Photodiodes (HPDs) or
Photomultiplier Tubes (PMTs) at the rate of 40 MHz.
• The data from each detector subsystem will be synchronized
with all other channels to take out any transmission timing
effects due to differing lengths of scintillating fibers and time of
flight.
QIE Cards
The front-end readout cards must condition the analog signal,
digitize it and send the result off board at 40 Mhz.
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Cards make extensive use of ASICs. The analog to digital converter
is a QIE ASIC (QIE8): Q (charge) I (integration) and E (encode)
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Multi-range technique: the input current is simultaneously
integrated on all ranges, lowest range what is not in full scale is
selected.
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The selected voltage is then put through an on-chip Flash ADC
(FADC) (non-linear). The outputs are a 5 bit mantissa representing
the voltage and a two-bit code indicating the range.
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Photograph of CMS HCAL Front End Module
2008:Liniarized ADC
Liniarization:https://twiki.cern.ch/twiki/pub/CMS/ChargeInjector/01239297.pdf
Correlations between
Slope and Intercept
Correlations between
Slopes for different
ranges
What do we have in the DB: slopes and
offsets for different QIEs
Unknown
channels
QIEs Info/DB
•Cross-checked our knowledge about QIE response: Use
data which was taken in 2005 at FNAL
• Performed check shows a very good agreement with DB
data, so we basically can say that besides of unknown 10%
our DB is correct
DB and Run
Slopes
Comparison
Missed info about QIEs
Channels for which information is missed (by subdetectors):
HB: 372 out of 2592
HE: 55 out of 2592
HO: 296 out of 2160
HF: full
Information we can restore:
HB: 156 channels out of 372 (for 72 we don’t have any info)
HE: all 55 – information is complete!!!
HO: ~50% of the missed info can be restored
Summary
• Check the information about QIE Data for HCAL
• Found that information is incomplete in DB
•Restore most of the information: Restored ALL info for HE
• Updated information in DB for QIEs boards which were
exchanged
• More info:
https://twiki.cern.ch/twiki/bin/view/CMS/ChargeInjector