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W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Wojtek Skulski
SkuTek Instrumentation
and
University of Rochester
Digital Signal Processing Electronics
for Nuclear Physics Applications
Small Business Innovation ResearchDepartment Of Energy Grant DE-FG02-03ER83778
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Outline
• Outline of grant work.
• Accomplishments.
• Hardware, firmware, software.
• Good resolution, low noise.
• Research and student projects @ UofR.
• Plans.
• Acknowledgements.
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Outline of the work
• The company: 75% of the grant work
• Development of waveform digitizers:• Single-channel, 12-bit DDC-1.
• Eight-channel, 10-bit DDC-8.
• Firmware and software.
• University of Rochester: 25% of the grant work.
• Data link between DDC-8 and universal logic XLM.
• University of Rochester: education and research projects.
• Performed in addition to this grant, extremely valuable.
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Single-channel, 12-bit DDC-1
Signal OUT
JTAG connector
USBprocessor connector
FPGA
Signal IN
ADC 65 MHz * 12 bits
Fast reconstruction DAC 65 MHz * 12 bits
Variablegain amp
Designed and built by WS.Used in several student projects during last 2 years.
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Diagnostic OUT40 MHz * 10 bits
JTAG connector
microprocessor
FPGA
ADC 40 MHz * 10 bits(8 channels)
16 bidirectional TTL lines + 1 in(fast parallel interface to XLM)
Analogsignal IN8 channelswithdigital offsetand gain control
RS-232
Logic connectors NIM 16 lines IN, 8 lines OUT
USB
RAM500 kB
ECL clock IN(optional)
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Gain=1, noise below 1 LSB
Intrinsic noise of the DDC-8 board
2 mV/ADC count
Time step (25 ns/step)220.0 240.0 260.0 280.0 300.0
516.0
517.0
518.0
519.0
520.0
pulse ADC gain = 1
ADC waveform 0
0.24 mV/ADC count
Time step (25 ns/step)340.0 360.0 380.0 400.0 420.0
530.0
535.0
540.0
545.0
550.0
555.0
560.0
pulse ADC gain = 8
ADC waveform 0
Gain=8, noise ~3 LSB (peak-peak)
Intrinsic noise is excellent
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Short filter, pulser resolution 0.37 keV
DDC-8 + research pulser Ortec 448
Dynamic range of 18 bits obtained with 5µs running sums
120
100
80
60
40
20
0
Cou
nts
17.98x103 17.9617.9417.9217.9017.8817.86
Measured pulser amplitude (nat. units)
ADC channel 2, maximum gain, 90% amplitude step
0.5µs trapezoidal filter
Solid line: gap 0.5 µsSdev = 5.02943 Mean = 17901.9Resolution = 0.028 %
Pulser leading edge = 20ns
40
30
20
10
0
Cou
nts
179.05x103 179.00178.95178.90178.85178.80178.75
Measured pulser amplitude (nat. units)
ADC channel 2, maximum gain, 90% amplitude step
5µs trapezoidal filter
Pulser leading edge = 20ns
Solid line: gap 0.5 µsSdev = 20.8234 Mean = 178899Resolution = 0.012 %
Long filter, pulser resolution 0.16 keV
Pulser peak = 179,000 ==> 18 bits
Maximum gain Maximum gain
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
DDC-8 + 1-inch NaI(Tl)
Threshold = 5keV
Trapezoidal filter with 5µs running sumsCounts
Energy (keV)0.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0 800.0
0.0
200.0
400.0
600.0
800.0
Compton back-scatter
33 keV, Ba X-ray662 keV
137 Cs Small NaI(Tl)Energy
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004Diagnostic channel
JTAG
Link connector to XLM-80Signal IN
8 channels
etc...
NIMconnector
NIM-level signals16*IN, 8*OUT
DDC-8 + XLM link board
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004 VME connectors
Linkdaughtercard
XLM-80motherboard
XLM-80 + DDC-8 link board (J.Toke, UofR)
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Digital link DDC-8 <=> XLM
Sustained transfer rate = 75 Mbytes/sec
Digital link: data transfer and handshake signals DDC-8 <=> XLM
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Documentwindow
Both software development and DAQ in the same environment
DDC-x software development and DAQ system
DAQwindows
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Education and R&D projects at Physics and Astronomy
• S.Zuberi, Digital Signal Processing of Scintillator Pulses in Nuclear PhysicsTechniques, Senior Thesis, Department of Physics and Astronomy, University ofRochester. Presented at Spring APS meeting, April 2003, Philadelphia, PA.
•Awarded the Stoddard prize for the best Senior Thesis in the Department.
• D.Miner, W.Skulski, F.Wolfs, Detection and Analysis of Stopping Muons Using aCompact Digital Pulse Processor, Summer Research Experience for Undergraduates,Department of Physics and Astronomy, University of Rochester 2003 (unpublished).
• P.Bharadwaj, Digital and analog signal processing techniques for low-backgroundmeasurements, graduate research started this Summer.
• P.Bharadwaj, W.Skulski, F.Wolfs, Developing an efficient triggering system forPHOBOS at RHIC, ongoing.
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Τraditional slow-tail representation
1 cm3 CsI(Tl) + phototube Single-channel digitizer DDC-1 at 48 Msamples/s * 12 bits natTh radioactive source
PID = TAIL / TOTAL
Note energy-independent PID
Particle ID from CsI(Tl)Senior Thesis by Saba Zuberi
Best Senior Thesis 2003Dept. of Physics and Astronomy
University of Rochester
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Energy spectrumCounts
Filtered energy (arb. units)0.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0 800.0 900.0 1.0E+3
0.0
50.0
100.0
150.0
200.0
250.0
Energy 1
662 keV, 137Cs
NaI 2" by 2"
0.884 keV/bin
77 keV, Pb X-ray
33 keV, Ba X-ray
Compton back-scatter
Signals from a Bicron 2”x2” NaI(Tl) detectordigitized with DDC-1 at 48 Msamples/s * 12 bits
137Cs
Response to scintillator pulses: NaI(Tl)Senior Thesis by S.Zuberi
Best Senior Thesis 2003, Dept. of Physics and Astronomy, University of Rochester
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Detection and Analysis of Stopping Muons#
BC-400 5” x 6”& phototube
Experiment controland data display
Digitizer board
#Daniel MinerUniversity of RochesterSummer 2003 REU
•Example of pulse processing & analysis•Table-top experiment•Several observables from one signal
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
ADC waveform ADC value
Time steps, 20.8 ns/step0.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0 800.0
1750.0
1800.0
1850.0
1900.0
1950.0
2.0E+3
2050.0
2100.0
2150.0Transient 3183
Signals from a BC-400 5”x6” scintillator
Stopping muon
Detection and Analysis of Stopping MuonsDaniel Miner, University of Rochester, Summer 2003 REU
Muon decay
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Measured muon lifetime in very good agreement with published valueAfter 4% capture correction agree to within 0.35%
Time between the leading and trailing pulsesDaniel Miner, University of Rochester, Summer 2003 REU
0
0.2
0.4
0.6
0.8
1
1.2
0 2 4 6 8 10
Delta T (microseconds)
Nor
mal
ized
Cou
nt
Normalized Fit Delta T
Normalized Experimental Delta T
Measured <τ>: 2.12 + 0.04 µsAccepted <τ>: 2.19703 + 0.00004 µs
In matter
In vacuum
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Vertex and centrality definition in real time
• Analog signals: Paddles, T0, ZDC.
• Logic signals from conventional NIM. • Signal processing: on-board FPGA.
• Accept/reject event within about 1 µsec.
Online trigger for PHOBOS with DDC-8Under development
Vertex definition from TACs.T0 OR ∆t, Paddle ∆t,ZDC ∆t.
PHOBOS @ RHIC
Centrality from paddle and ZDC.
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Plans
• New board is under development.• RIA, RHIC, low-background underground measurements.
• Design objectives.• High reliability.• Remote operation and diagnostics.• Low cost per channel.• High level of integration (many channels per board).• On-board DSP.• Integration with existing infrastructure (VME).
• Status: schematic almost finished.• Prototype will be assembled this Fall.
W.Skulski GRETINA Electronics Workshop, Argonne, 24-25 July 2004
Acknowledgements
• SkuTek Instrumentation.• Joanna Klima, WS (Principal Investigator).
• University of Rochester.• Jan Toke: digital link.• Frank Wolfs: support for DDC-8 development.
• Graduate students.• Palash Bharadwaj.
• Undergraduate students.• Suzanne Levine, Daniel Miner, Len Zheleznyak, Saba Zuberi.
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