Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ and Analysis Bob Michaels with...
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Transcript of Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ and Analysis Bob Michaels with...
![Page 1: Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ and Analysis Bob Michaels with Reminder about Nov 2006 Results Specification of new.](https://reader035.fdocuments.us/reader035/viewer/2022062511/5514dfab55034693478b56ca/html5/thumbnails/1.jpg)
Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ
Integrating Compton DAQ
and Analysis
Bob Michaels with
• Reminder about Nov 2006 Results
• Specification of new FADC
• Data Analysis with FADC
Gregg Franklin Alexandre Camsonne Sirish Nanda
![Page 2: Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ and Analysis Bob Michaels with Reminder about Nov 2006 Results Specification of new.](https://reader035.fdocuments.us/reader035/viewer/2022062511/5514dfab55034693478b56ca/html5/thumbnails/2.jpg)
Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ
FADC
fanout
to counting DAQ
detector PMT
(Neg. HV)
amplifier
amplifier
~ 20 m
~ 120 m
~ 30 m
1st floor cnt room
2nd floor cnt room
Compton photons
Nov 2006 Compton Integration DAQ
• FADC Data integrated over helicity pulse (30 msec)
• FADC samples also available.
• BCM, Compton laser status, & EPICS data available.
Inside Hall A
![Page 3: Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ and Analysis Bob Michaels with Reminder about Nov 2006 Results Specification of new.](https://reader035.fdocuments.us/reader035/viewer/2022062511/5514dfab55034693478b56ca/html5/thumbnails/3.jpg)
Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ
Time (ea. bin 5 nsec)
Vo
ltag
e
(fu
ll sc
ale
~2
V)
FADC Samples that look like signal
![Page 4: Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ and Analysis Bob Michaels with Reminder about Nov 2006 Results Specification of new.](https://reader035.fdocuments.us/reader035/viewer/2022062511/5514dfab55034693478b56ca/html5/thumbnails/4.jpg)
Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ
Time (ea. bin 5 nsec)
Vo
ltag
e
(fu
ll sc
ale
~2
V)
FADC Samples that look like background
~ 50 nsec
![Page 5: Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ and Analysis Bob Michaels with Reminder about Nov 2006 Results Specification of new.](https://reader035.fdocuments.us/reader035/viewer/2022062511/5514dfab55034693478b56ca/html5/thumbnails/5.jpg)
Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ
Integral over the width of individual pulsesIt’s what the counting DAQ does, too.
Clear Compton events seen.
LED calibrates energy scale.
Brehmstrahlung background (1/E)
![Page 6: Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ and Analysis Bob Michaels with Reminder about Nov 2006 Results Specification of new.](https://reader035.fdocuments.us/reader035/viewer/2022062511/5514dfab55034693478b56ca/html5/thumbnails/6.jpg)
Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ
To obtain a digital integral with zero deadtime:
use so-called “Accumulator” = sum of samples
subject to cut conditions :
• Cut conditions are optional
• Sample above a certain threshold.
• Sample below another threshold.
over 30 msec helicity window
( can be turned off )
( eliminates noise )
( eliminates background )
Full-sampling mode used to evaluate systematic errors.
![Page 7: Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ and Analysis Bob Michaels with Reminder about Nov 2006 Results Specification of new.](https://reader035.fdocuments.us/reader035/viewer/2022062511/5514dfab55034693478b56ca/html5/thumbnails/7.jpg)
Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ
Setting up Accumulator (Nov ’06 data)
Problems:
1. The high cut didn’t work so we made big pulses “clip” at zero.
2. We did not know the pedestal of accumulator (understood later).
FADC sample (ADC units)
![Page 8: Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ and Analysis Bob Michaels with Reminder about Nov 2006 Results Specification of new.](https://reader035.fdocuments.us/reader035/viewer/2022062511/5514dfab55034693478b56ca/html5/thumbnails/8.jpg)
Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ
Asymmtries from AccumulatorDay 1 : IHWP out Day 2 : IHWP in
and different thresholds !
FLI
P
lase
r po
l.La
ser
of
f.
![Page 9: Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ and Analysis Bob Michaels with Reminder about Nov 2006 Results Specification of new.](https://reader035.fdocuments.us/reader035/viewer/2022062511/5514dfab55034693478b56ca/html5/thumbnails/9.jpg)
Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ
Summary of Nov `06 Experience• Saw Compton events, good signal-to-background
• Too much electronic noise
• Accumulators worked well, but ...
Need shorter cable runs.
Want no amplifiers
Get more gain with 12-stage PMT ?
Asymmetries made no sense until we realized …
Pedestal subtraction wrong and threshold dependent.
Need more info. to subtract pedestals.
![Page 10: Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ and Analysis Bob Michaels with Reminder about Nov 2006 Results Specification of new.](https://reader035.fdocuments.us/reader035/viewer/2022062511/5514dfab55034693478b56ca/html5/thumbnails/10.jpg)
Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ
Specification of new FADC with fancier accumulators
by Bob Michaels and Gregg Franklin
http://www.jlab.org/~rom/fadcspec.pdf
• Spec has been sent to two vendors: SISGmbH and CAEN.
• Expect boards from each vendor in ~August.
• Old SISGmbH boards can be updated (new firmware)
• Boards have other uses in Hall A.
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Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ
Resolution 12 bits
Sampling Rate 250 MHz (or 200)
Range
Buffer
Accumulator
Custom FADC based on SIS3320 / CAEN1720.
V5 bipolar
61025.8 Samples
See next slides
( 33 msec )
CAEN SIS
![Page 12: Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ and Analysis Bob Michaels with Reminder about Nov 2006 Results Specification of new.](https://reader035.fdocuments.us/reader035/viewer/2022062511/5514dfab55034693478b56ca/html5/thumbnails/12.jpg)
Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ
Vol
tage
Time
Zero Volts
Typical Big Pulse(background)
Typical Small Pulse(Compton event)
Low Threshold
High Threshold
How Thresholds Work
![Page 13: Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ and Analysis Bob Michaels with Reminder about Nov 2006 Results Specification of new.](https://reader035.fdocuments.us/reader035/viewer/2022062511/5514dfab55034693478b56ca/html5/thumbnails/13.jpg)
Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ
Accumulator Feature
• Samples added between Tstart and Tstop
• Subject to cut conditions (optional).
• Number of samples available N
Ex #1 Data above a threshold, or data between a low & high threshold.
Ex #2 Data “N” pulses before & after a threshold (more linear response).
sample
See the spec for details.
Necessary for pedestal subtraction
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Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ
)( APCV
APCV Voltage ; Conversion ; Pedestal ; ADC value
i
isamples ANPS )(
dataallthreshhigh
AA .
.
;11
1threshhighphysics ABwhereBSS
Example : How to Analyze Data
FADC measurements
Integrated Signal ( C cancels in Asy. )
Deadtime Correction ( high threshold ``robs’’ signal )
Physical Signal
to use in Asymmetry.
B = background empirical correction
missing in Nov ‘06
thanks, Gregg !
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Bob MichaelsParity Collab. Mtg. May 17, `07 Integrating Compton DAQ
Conclusions – Integrating Compton DAQ
• ``Data Analysis on a Chip” looks promising, may have
widespread applications
• FADC with new accumulators ready this summer. ~ August
• but yet to be proven.