1. W.Skulski Phobos Workshop April /2003 Digital Pulse Processor DDC-8 (Universal Trigger Module) for PHOBOS. Wojtek Skulski University of Rochester

2. 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.

3. 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.

4. 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.

5. W.Skulski Phobos Workshop April /2003 Signal OUT 40 MHz * 10 bits JTAG connector micro processor FPGA ADC 40 MHz * 10 bits (8 channels) 16 bidirectional TTL lines + 1 in (fast parallel interface to XLM) Analog signal IN 8 channels with digital offset and gain control RS-232 Logic connectors NIM 16 lines IN, 8 lines OUT USB RAM 500 kB ECL clock IN (optional)

6. 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 USB processor connector FPGA Signal IN ADC 65 MHz * 12 bits Fast reconstruction DAC 65 MHz * 12 bits Variable gain amp

7. W.Skulski Phobos Workshop April /2003 ASC Nyquist filter ADC Sample rate processor Waveform memory Event rate processor Signal from preamplifier Clock Gain and offset control Optional external trigger analog digital Legend: ASC = Analog Signal Conditioning ADC = Analog to Digital Converter Trigger Pulse height and shape Individual trigger

8. W.Skulski Phobos Workshop April /2003 Analog section Digital section Correlation processor User-defined 17 I/O lines OR parallel interface Composite internal trigger Channel 1 Analog section Digital section Channel 2... Analog section Digital section Channel 8 Optional external trigger (one of the 16 NIM in lines) Internal triggers from channels 1…8 16*NIM in8*NIM out Analog section Digital section Channel OUT 17*TTL in/out

9. W.Skulski Phobos Workshop April /2003 8 chan XLM-72 900 MFLOPs 4 MB 40,000 gates DAQ 8 chan 32 flash ADCs 32*NIM out 8 chan 64*NIM in On-board monitoring 1.2 million gates in the FPGAs On-the-fly data preprocessing Four independent parallel interfaces, 100+ MB/s. VME Flash ADC front end

10. 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, I 2 C. 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

11. 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: t pulse < t sampling. NaI(Tl): t pulse > t sampling. CsI(Tl): particle identification. Phoswich: two-component FAST-SLOW pulses.

12. W.Skulski Phobos Workshop April /2003 Signal from a Bicron BC-404 detector digitized 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 ns1 sample = 0.2 ns Tek screen for reference Response to scintillator pulses: fast plastic scintillator A typical pulse in PHOBOS environment

13. W.Skulski Phobos Workshop April /2003 CsI(Tl) crystal cosmic ray phototube teflon Bicron BC-404 FAST SLOW Signal from a phoswich detector digitized with the DDC-1 48 Msamples/s at 12 bits FAST clearly separated from SLOW 1 sample = 20.8 ns

14. W.Skulski Phobos Workshop April /2003 Signals from a Bicron 2”x2” NaI(Tl) detector digitized with the 1-channel prototype at 48 Msamples/s * 12 bits 137 Cs Medium-fast scintillator pulses: NaI(Tl)

15. W.Skulski Phobos Workshop April /2003  -ray 1 cm 3 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)

16. W.Skulski Phobos Workshop April /2003  raditional slow-tail representation 1 cm 3 CsI(Tl) + phototube 1-channel prototype at 48 Msamples/s * 12 bits nat Th radioactive source PID = TAIL / TOTAL Note energy-independent PID Particle ID from CsI(Tl)

17. W.Skulski Phobos Workshop April /2003 Neutron Calorimeter SuperBall. 16 m 3 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.

18. 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.

19. W.Skulski Phobos Workshop April /2003 Signal from a pocket NIM pulser digitized with the DDC-8 at 40 Msamples/s * 10 bits Excellent response to a very fast pulse seen with the “spy channel” t pulse < t sampling. Digitization made possible by the Nyquist filter f filter = 1/4 f sampling Latency = 300ns. Input pulse t 0 +300ns How fast can we digitize the pulse?

20. 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.

21. 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.

22. 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 1 st 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.

23. 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.