W.Skulski Phobos Workshop April /2003 Digital Pulse Processor DDC-8 (Universal Trigger Module) for...
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Transcript of W.Skulski Phobos Workshop April /2003 Digital Pulse Processor DDC-8 (Universal Trigger Module) for...
W.Skulski Phobos Workshop April/2003
Digital Pulse Processor DDC-8
(Universal Trigger Module)
for PHOBOS.
Wojtek Skulski
University of Rochester
W.Skulski Phobos Workshop April/2003
Outline
•Trigger application in PHOBOS.•Description of the Universal Trigger Module DDC-8.•Two configurations:
1. Standalone module without DAQ readout.
2. VME front-end with DAQ readout.
•Response to scintillator pulses.
•Programming tools:
•FPGA programming tools.
•Embedded microprocessor tools.
•PC GUI programming environment.
W.Skulski Phobos Workshop April/2003
Vertex and centrality definition in real time
• Analog signals: Paddles, Cerenkov, ZDC.• Logic signals from conventional NIM. • 1st level processing: DDC.• 2nd level processing: XLM, optional.• Accept/reject event within about 1 sec.
Online trigger
Vertex definition from TACs.T0 OR t, Paddle t,ZDC t.
PHOBOS @ RHIC
Centrality from paddle and ZDC.
W.Skulski Phobos Workshop April/2003
Possible configurations
•Standalone Universal Trigger Module DDC-8.• 8 flash ADC channels + 41 logic I/O.
• Standalone data acquisition and histogramming.• Counting House interfaces: USB and JTAG.• Tunnel interface: RS-232.• Real-time decision: fast. • DAQ readout: no.
•The combo system UTM+XLM.• 8, 16, 24, or 32 flash ADC channels + many logic I/Os.• Real-time decision: slower due to “additional layer”. • DAQ readout: yes.• More complicated programming.
W.Skulski Phobos Workshop April/2003
Signal 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 Phobos Workshop April/2003
Single channel 12-bit prototype, development and testing
• Input channel for waveform capture, up to 65 Msamples/s.
• Output reconstruction channel for development and diagnostic.
• The channel design to be used for the 12-bit multichannel board.
Signal OUT
JTAG connector
USBprocessor connector
FPGA
Signal IN
ADC 65 MHz * 12 bits
Fast reconstruction DAC 65 MHz * 12 bits
Variablegain amp
W.Skulski Phobos Workshop April/2003
Analogsection
Digitalsection
Correlationprocessor
User-defined17 I/O lines
OR
parallelinterface
Compositeinternaltrigger
Channel 1
Analogsection
Digitalsection
Channel 2
...Analogsection
Digitalsection
Channel 8
Optional external trigger (one of the 16 NIM in lines)
Internal triggersfrom channels 1…8
16*NIM in 8*NIM out
Analogsection
Digitalsection
Channel OUT
17*TTL in/out
W.Skulski Phobos Workshop April/2003
8 chanXLM-72
900 MFLOPs4 MB
40,000 gates
DAQ8 chan
8 chan
32 flash ADCs
32*NIM out
8 chan
64*NIM in
On-board monitoring
1.2 million gatesin the FPGAs
On-the-fly datapreprocessing
Four independent parallel interfaces, 100+ MB/s.
VME
Flash ADC front end
W.Skulski Phobos Workshop April/2003
# of analog input channels 8.# of analog output channels 1.# of logic inputs NIM 16. # of logic outputs NIM 8.# of in/out lines TTL 16+1.
Fast interfaces USB, parallel.Slow interfaces RS-232, SPI, I2C.Waveform memory 12 sec.On-board microprocessor 8 bits, 10 MIPS.Histogramming memory 0.5 MB.Packaging NIM, standalone.
Intermediate scale: SuperBall+DwarfBall.Medium scale: PHOBOS trigger.Small scale: table-top DPP systems, student research projects, DPP algorithm development.
DDC-8 features
W.Skulski Phobos Workshop April/2003
Response to scintillation pulses
•DDC-8 firmware is under development.
•Results obtained with DDC-1, 48 MHz @ 12 bits.
•Very fast plastic BC-404: tpulse < tsampling.
•NaI(Tl): tpulse > tsampling.
•CsI(Tl): particle identification.
•Phoswich: two-component FAST-SLOW pulses.
W.Skulski Phobos Workshop April/2003
ADC trace Sample value
Sample number20.0 30.0 40.0 50.0 60.0
1400.0
1600.0
1800.0
2.0E+3
2200.0
Samples
Signal from a Bicron BC-404 detectordigitized with the 1-channel prototype at 48 Msamples/s * 12 bits
Reliable digitization thanks to the antialiasing filter.
Excellent response to a very fast pulse
1 sample = 20.8 ns 1 sample = 0.2 ns
Tek screen for reference
Response to scintillator pulses: fast plastic scintillatorA typical pulse in PHOBOS environment
W.Skulski Phobos Workshop April/2003
CsI(Tl) crystal
cosmic ray
phototube
teflon
Bicron BC-404FAST
SLOWADC trace Sample value
Sample number0.0 50.0 100.0 150.0 200.0
1700.0
1800.0
1900.0
2.0E+3
2100.0
SLOW
FAST
Samples
Signal from a phoswich detectordigitized with the DDC-1 48 Msamples/s at 12 bits
FAST clearly separated from SLOW
1 sample = 20.8 ns
W.Skulski Phobos Workshop April/2003
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
Compton back-scatter
33 keV, Ba X-ray
77 keV, Pb X-ray
0.884 keV/bin
NaI 2" by 2"
662 keV, 137Cs
Energy 1
Signals from a Bicron 2”x2” NaI(Tl) detectordigitized with the 1-channel prototype at 48 Msamples/s * 12 bits
137Cs
Medium-fast scintillator pulses: NaI(Tl)
ADC waveformSample value
Sample number, 20.8 ns/sample400.0 420.0 440.0 460.0 480.0
1.0E+3
1500.0
2.0E+3
Samples NaI(Tl) 2" by 2"
W.Skulski Phobos Workshop April/2003
-ray
1 cm3 CsI(Tl) + phototube 1-channel prototype at 48 Msamples/s * 12 bits
Note pulse shape dependence on type of radiation.
-particle
Response to scintillator pulses: CsI(Tl)
ADC trace Sample value
Sample number50.0 100.0 150.0 200.0
1900.0
1950.0
2.0E+3
2050.0
2100.0
gamma-ray
Samples
ADC trace Sample value
Sample number50.0 100.0 150.0 200.0
2.0E+3
2050.0
2100.0
alpha-particle
Samples
W.Skulski Phobos Workshop April/2003
raditional slow-tail representation
1 cm3 CsI(Tl) + phototube
1-channel prototype
at 48 Msamples/s * 12 bits
natTh radioactive source
PID = TAIL / TOTAL
Note energy-independent PID
Particle ID from CsI(Tl)
W.Skulski Phobos Workshop April/2003
Neutron Calorimeter SuperBall.16 m3 organic liquid scintillator.
• Online pulse shape analysis with DDC.
• Charged particle ID with CsI(Tl)/plastic.
• Neutron capture counting and timing.
• 1st level processing: DDC.
• 2nd level processing: XLM.
Research application: SuperBall + DwarfBall
4 charged particle detector DwarfBall/DwarfWall.Plastic+CsI(Tl) phoswich detectors.
W.Skulski Phobos Workshop April/2003
Vertex and centrality definition in real time
• Analog signals: Paddles, Cerenkov, ZDC.• Logic signals from conventional NIM. • 1st level processing: DDC.• 2nd level processing: XLM, optional.• Accept/reject event within about 1 sec.
Online trigger
Vertex definition from TACs.T0 OR t, Paddle t,ZDC t.
PHOBOS @ RHIC
Centrality from paddle and ZDC.
W.Skulski Phobos Workshop April/2003
Signal from a pocket NIM pulserdigitized with the DDC-8 at 40 Msamples/s * 10 bits
Excellent response to a very fast pulse seen with the “spy channel”
tpulse < tsampling.
Digitization made possible
by the Nyquist filter
ffilter = 1/4 fsampling
Latency = 300ns.
Input pulse
t0+300ns
How fast can we digitize the pulse?
W.Skulski Phobos Workshop April/2003
Time budget
•ADC pipeline latency: 9*12.5ns = 112.5 ns.
•FPGA input: 25 ns.
•Nyquist filter: 100 ns.
•Tunnel -> CH propagation: 100 ns.
•Left-right time diff: 100 ns.
•TAC response: 300 ns.
•TOTAL = 0.74 s.
•Note: TAC output very likely can be made faster.
W.Skulski Phobos Workshop April/2003
Software and firmware development tools
•Entry-level software development.• All development tools are free.
• FPGA: XILINX WebPack ISE.• Embedded micro: Keil C compiler, code restricted to 4kB.• PC GUI: Shareware edition of BlackBox Component Builder.
•Expert-level software development.• All tools discounted for universities.• FPGA.
•VHDL tools: XILINX ISE, full version.•Graphical tools: MatLab and XILINX System Generator.
• Embedded micro: Keil C compiler, full version.• PC GUI: Full edition of BlackBox Component Builder.
W.Skulski Phobos Workshop April/2003
Obstacles and showstoppers
•Obstacles.• Firmware & software development takes time.
• Need an expert at the Phobos end.• Only one board exists, two more being assembled, all are already booked.• The 1st board has not been fully tested yet.
•Showstoppers?• Does Phobos need this tool?• Can Phobos designate an expert?• Recent deep cut in funding cannot be ignored.
W.Skulski Phobos Workshop April/2003
Summary
•The technology is under control.•Glitches, if any, will be resolved.
•One DDC-8 assembled, works OK, but not yet fully tested.
•Two more boards being assembled.
•Firmware & software development will take time.
•A possible showstopper: recent cut in funding.
•Does Phobos need this device?•My personal belief: if there is need, the expert will step forward.
•The situation looks good, but not hopeless.