Digital Signal Processing Electronics for Nuclear Physics Applications

Transcription

1 Digital Signal Processing Electronics for Nuclear Physics Applications Small Business Innovation Research Department Of Energy Grant DE-FG02-03ER83778 Wojtek Skulski SkuTek Instrumentation and University of Rochester

2 Outline Outline of grant work. Accomplishments. Hardware, firmware, software. Good resolution, low noise. Research and student UofR. Plans. Acknowledgements.

3 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.

4 Single-channel, 12-bit DDC-1 Designed and built by WS. Used in several student projects during last 2 years. JTAG connector ADC 65 MHz * 12 bits FPGA Variable gain amp USB processor connector Signal IN Signal OUT Fast reconstruction DAC 65 MHz * 12 bits

5 RAM 500 kb JTAG connector ADC 40 MHz * 10 bits (8 channels) micro processor RS-232 USB Analog signal IN 8 channels with digital offset and gain control FPGA ECL clock IN (optional) Diagnostic OUT 40 MHz * 10 bits Logic connectors NIM 16 lines IN, 8 lines OUT 16 bidirectional TTL lines + 1 in (fast parallel interface to XLM)

6 Intrinsic noise of the DDC-8 board Intrinsic noise is excellent Gain=1, noise below 1 LSB Gain=8, noise ~3 LSB (peak-peak) 2 mv/adc count ADC waveform mv/adc count ADC waveform pulse ADC gain = pulse ADC gain = Time step (25 ns/step) Time step (25 ns/step)

7 DDC-8 + research pulser Ortec 448 Dynamic range of 18 bits obtained with 5µs running sums Short filter, pulser resolution 0.37 kev Long filter, pulser resolution 0.16 kev ADC channel 2, maximum gain, 90% amplitude step Maximum gain 0.5µs trapezoidal filter 30 ADC channel 2, maximum gain, 90% amplitude step Maximum gain 5µs trapezoidal filter Counts Solid line: gap 0.5 µs Sdev = Mean = Resolution = % Counts 20 Solid line: gap 0.5 µs Sdev = Mean = Resolution = % Pulser leading edge = 20ns 20 Pulser leading edge = 20ns Measured pulser amplitude (nat. units) 17.98x Measured pulser amplitude (nat. units) x10 3 Pulser peak = 179,000 ==> 18 bits

8 DDC inch NaI(Tl) Threshold = 5keV Trapezoidal filter with 5µs running sums Counts kev, Ba X-ray Compton back-scatter 137 Cs Small NaI(Tl) Energy 662 kev Energy (kev)

9 DDC-8 + XLM link board NIM-level signals 16*IN, 8*OUT NIM connector JTAG etc... Signal IN 8 channels Link connector to XLM-80 Diagnostic channel

10 XLM-80 + DDC-8 link board (J.Toke, UofR) XLM-80 mother board Link daughter card VME connectors

11 Digital link DDC-8 <=> XLM Sustained transfer rate = 75 Mbytes/sec Digital link: data transfer and handshake signals DDC-8 <=> XLM

12 DDC-x software development and DAQ system DAQ windows Both software development and DAQ in the same environment Document window

13 Education and R&D projects at Physics and Astronomy S.Zuberi, Digital Signal Processing of Scintillator Pulses in Nuclear Physics Techniques, Senior Thesis, Department of Physics and Astronomy, University of Rochester. 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 a Compact 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-background measurements, graduate research started this Summer. P.Bharadwaj, W.Skulski, F.Wolfs, Developing an efficient triggering system for PHOBOS at RHIC, ongoing.

14 Particle ID from CsI(Tl) Senior Thesis by Saba Zuberi Best Senior Thesis 2003 Dept. of Physics and Astronomy University of Rochester Τraditional slow-tail representation 1 cm 3 CsI(Tl) + phototube Single-channel digitizer DDC-1 at 48 Msamples/s * 12 bits nat Th radioactive source PID = TAIL / TOTAL Note energy-independent PID

15 Response to scintillator pulses: NaI(Tl) Senior Thesis by S.Zuberi Best Senior Thesis 2003, Dept. of Physics and Astronomy, University of Rochester Signals from a Bicron 2 x2 NaI(Tl) detector digitized with DDC-1 at 48 Msamples/s * 12 bits Counts Energy spectrum Energy kev, Ba X-ray 137 Cs 662 kev, 137Cs NaI 2" by 2" kev, Pb X-ray Compton back-scatter kev/bin E+3 Filtered energy (arb. units)

16 Detection and Analysis of Stopping Muons # Experiment control and data display # Daniel Miner University of Rochester Summer 2003 REU BC x 6 & phototube Digitizer board Example of pulse processing & analysis Table-top experiment Several observables from one signal

17 Detection and Analysis of Stopping Muons Daniel Miner, University of Rochester, Summer 2003 REU Signals from a BC x6 scintillator ADC value ADC waveform Transient E Muon decay Stopping muon Time steps, 20.8 ns/step

18 Time between the leading and trailing pulses Daniel Miner, University of Rochester, Summer 2003 REU Measured muon lifetime in very good agreement with published value After 4% capture correction agree to within 0.35% 1.2 Normalized Fit Delta T 1 Normalized Experimental Delta T N ormalized Count Measured <τ>: µs Accepted <τ>: µs In matter In vacuum Delta T (microseconds)

19 Online trigger for PHOBOS with DDC-8 Under development RHIC Analog signals: Paddles, T0, ZDC. Logic signals from conventional NIM. Signal processing: on-board FPGA. Accept/reject event within about 1 µsec. Centrality from paddle and ZDC. Vertex definition from TACs. T0 OR t, Paddle t, ZDC t. Vertex and centrality definition in real time

20 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.

21 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.