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COMET Comments --- Readout for the COMET e Tracker

COMET Comments --- Readout for the COMET e Tracker. With special THANKS to my sponsors of this talk Satoshi Mihara Manobu Tanaka Masaharu Aoki. Ed Hungerford University of Houston (for the COMET Collaboration). Introduction to COMET.

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COMET Comments --- Readout for the COMET e Tracker

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  1. COMET Comments --- Readout for the COMET e Tracker With special THANKS to my sponsors of this talk Satoshi Mihara Manobu Tanaka Masaharu Aoki Ed Hungerford University of Houston (for the COMET Collaboration) Ed Hungerford

  2. IntroductiontoCOMET • COMET (Phase I) is a search for coherent, neutrino-less conversion of muons to electron (μ-e conversion) at a single event sensitivity of 0.5x10-16 • The experiment offers a powerful probe for new physics beyond the Standard Model. • COMET will be undertaken at J-PARC. Phase I (COMET) uses a slow-extracted, bunched 8 GeV proton beam from the J-PARC main ring. • A proposal was submit to J-PARC Dec. 2007, and a Conceptual Design Report submitted June 2009. COMET now has Stage-1 approval from the J-PARC PAC (July 2009), and is completing R&D for the TDR. Ed Hungerford

  3. Design Considerations for COMET (and generally all high precision measurements of zero) • Electron Resolution Minimal Detector Material – Thin, Low Z Vacuum Environment REDUNDENT measurements of the electron track • Rates Up to 500 kHZ single rates Large channel count R/O timing (~1 ns) and analog information • Dynamic Range Protons 30-40 times Eloss for MIP Pileup and saturation Maintain MIP track efficiency • Low-Power, Low-foot print electronics Heat Signal Transmission through the vacuum walls Noise • Robust measurements • REDUNDANCY (Redundancy, Redundancy, Redundancy) Ambiguous hits, dead channels, accidentals Reconstruction of ghost tracks Ed Hungerford for the COMET collaboration

  4. μ→eγ and μ-e Conversion μ→eγ : Accidental background is given by (rate)2. To push sensitivity the detector resolutions and timing must be improved. However, (in particular photon detection) it would be hard to do better than MEG. The ultimate sensitivity of MEG is about 10-14 (with a run of 108/sec). μe conversion : Improvement of a muon beam is possible, both in purity (no pions) and in intensity (muon collider R&D). Higher beam intensity can be used with present timing technology because no coincidence is required. Ed Hungerford

  5. COMET at J-PARC Pulsed Proton Beam p Source B(m + Al)  e + Al <10-16 electron Transport  target  Transport 5 m Detection • Modification of MECO/MELC • Requires slow extracted, pulsed beam ~8 GeV • Mu2e at FNAL is another MECO resurrection Ed Hungerford

  6. Target and Detector Solenoids a muon stopping target, curved solenoid,tracking chambers, and a calorimeter/trigger and cosmic-ray shields. Ed Hungerford

  7. Comparison to MECO Proton Target - tungsten (MECO) - graphite (J-PARC) Muon Transport - Magnetic fields and solenoids are different. - Efficiency of the muon transport is equivalent Spectrometer - 1011 stopping muons/sec -Straight Solenoid (MECO) >500 kHz/wire - Curved (COMET) ~1kHz /wire Planer Tracker MECO Ed Hungerford

  8. COMET Tracker and Calorimeter Background Total Tracker Rates/plane 600 kHz Ed Hungerford

  9. Muon-to-Electron (μ-e) Conversion Lepton Flavor Violation U H M E P nucleus m - μ Decay in Orbit (DIO) μ- → e-νν Lepton Flavor Changes by one unit Coherent Conversion μ- + A → e-+ A Nuclear Capture μ- + A →ν+ [N +(A-1)] Ed Hungerford

  10. Background Rejection (~107 s) (preliminary) • 6/9/1010 • Ed Hungerford • 10

  11. Tracking Array 5 Planes – 4 Arrays per plane Each plane arranged in an x,x’,y,y’ geometry of arrays Each array composed of 13 straw units of 16, 5mm diameter straws Mounted double-array Unit • 16 straws/unit • 208 straws/array • 832 straws/plane • 4160 straws/detector 1.2 m Ed Hungerford

  12. Manifold Ed Hungerford

  13. Flex Ribbon Cable through Manifold to FEB Fused HV 15 ns LRC Filter/channel Ed Hungerford

  14. Readout Architecture • On-Detector amplification and digitizing – events passed by optical fiber in serial to an external DAQ (Parallel transfer is also possible) • Electronics based on CMOS to conserve space and power (<65 Mw/ch) – radiation damage is not a problem • Mounted on the detector frame • A (MECO) system has been previously prototyped and demonstrated • COMET Data rates are reasonable

  15. COMET Tracker FE Organization Assuming: 60-125MHz clock and 10-20 clock ticks for an event (160 ns) (10-20+ 11) x 4x5x1.5 words for an event and 16 bits for a word 1k/s event rate The total data rate is ~10-15 Mb/s with zero suppression Ed Hungerford

  16. An Example The MECO Readout Architecture Separated PA And Digitizer From Anode Wire Sequencer Plane ID for readout To External DAQ Ed Hungerford

  17. MECO Prototype • FEATURES • The number of data transfer lines is 24 (16 data + 6 control) • A system clock is regenerated by the local buss sequencer • A trigger input is associated with readout units • A trigger reset counter determines the data time stamp • A system reset to return to standard operating conditions • A slow control buss for control and monitoring • Low voltage power of +3.3V(300A) and -3.3V (100A) • Total Power < 1.8 kW (PA and Digitizer only) • 6/9/1010 • 05-30-09 • Ed Hungerford • Ed Hungerford for the COMET collaboration • 17 • 17

  18. Drift Simulation Trajectory Trajectory Position Along Y (cm) Wire Wire Gas – 80 %CF4/20% C6H10 Velocity - 8.5 cm/μs Drift Time - 45 ns Ed Hungerford

  19. Measurements and Simulations Simulated Anode signal Simulated Charge 15 ns Filter Ed Hungerford

  20. The MECO Prototyped System • The Digitizing Board layout is completed, tested, and the digitizing ASIC designed. Digitizing Boards Connected by flex cable FEB Board Mother Board with FPGA Memory and PCI controller A front-end board was developed to test the ASD-4 and a driver board is used to adapt the LVDS output to our lab CAMAC TDC. Ed Hungerford Elefant Chips (2 x 8 channels)

  21. 32 Channel MECO Prototype Ed Hungerford

  22. Specifications for COMETASIC preamp Ed Hungerford

  23. ASIC Digitizer • Digitizer ASIC Design •  based on the ELEFANT ASIC used in BABAR (8 channels/ASIC) • Work in collaboration with design engineers at LBL • Rescale ASIC to 0.25 m technology and 3.2 V interfaces • Solves identified problems with the ELEFANT design • Change clock frequency (20-60 Mhz) • Change from waveform sampling to time-slice integration • Increase ADC bits to 10 • ~5 s Latency, self or external trigger • Power Consumption 65 mW/channel (Total Power 1,650 W) Design (LBL Engineer) $518K; Fabrication (2prototypes) 2 x $45k; Preproduction samples $50k; Production and packaging $231k, Testing $42k => $931k + 37% contingency Several more modern Waveform (ADC Sampling) ASICS designs are Possible for COMET -- e.g. Belle, PSI designs, ATLAS, etc Ed Hungerford

  24. Benefits: reduce noise, simplify the system design, better technology, lower power consumption, lower system cost. Prediction of the production cost is ~$8-15 per channel. RAM event buffer MUX and Output FIFO Local Bus 8ADC Latency buffer Clock 8TDC Logic control Trigger Time stamp Digital chip Redesign

  25. MECO Digitizer chip specs Ed Hungerford

  26. Elefant II ASIC Time and amplitude samples stored together in a latency pipeline Ed Hungerford

  27. A More Modern Design CDC – Belle Central Drift Chamber Ed Hungerford

  28. Other ExamplesReadout of ATLAS TRT • Based on two ASICs: front-end + digitization • ASDBLR • Front-end, 8-ch • Separate preamps • Track detection • TR photon detection • Ternary outputs • DTMROC • Digitization, 16-ch • TDC + FIFO + Serialization • Each beam bunch has one slice in FIFO • Control and thresholds to ASDBLR • Power consumption: 40 mW/ch

  29. Each ROC has a FPGA to control the readout sequence from the Elefant II chips. Data are stored on the board temporarily in the dual-port RAM. Configurations, like the number of channels connected to this board, readout mode (sparse mode, zero-suppression mode, etc.), are configured through the I2C bus. To FE Board CONN. CONN. CONN. CONN. CONN. CONN. High Speed Serial Bus I2C Dual Port RAM FPGA Virtex-II pro CPLD PROM Clock Trigger Reset Distribution V3.3 REG Transmitter I2C V2.5 REG Pwr Conn. RJ-45 RJ-45 RJ-11 ROC Board Design Ed Hungerford

  30. Fast Control Signal • Reset, Trigger, and Reference clock are provided by DAQ system (Trigger and Fast Control Fan-out ). • These are transmitted as differential signals (LVDS). • Reference clock is 10MHz with reasonable jitter. On the module controller or ROC, this clock frequency will be divided by PLL to the sampling frequency (40-60MHz) with much smaller jitter (~200ps) to satisfy ADC requirement. • Event numbers are embedded in the trigger signal (real time trigger signal followed with the number) . • The Control module feeds the fast control signal to each ROC Box through 4 pairs low skew differential, shielded cable. No matter how far the ROC is from the module controller, all these Fast Control lines must have the same length to reduce the time skew. This will also ensure the timing accuracy for the whole system. Ed Hungerford

  31. Data Transfer • Data transfer from ROC to the module controller uses shielded twisted pair cable (low skew <150ps /10m). • From the module controller, data passes feedthrough to the Event Builder of DAQ: differential copper wire or optic fiber. • Differential copper wire: • Easy to install from the vacuum wall. • Can be 100Mb/s (CAT-5e) or 200Mb/s (CAT-6). Up to 100m • Full bandwidth is not used due to protocols (handshaking). • Cheaper. • Optic fiber: • Penetrations through the vacuum wall? Hermetic feed through exits. No engineering experience. • Fast. Can be ~Gb/s. ~km long. • Radiation hardness of the transceiver should be considered. • Costs more. Ed Hungerford

  32. 31 28 27 25 24 23 22 20 19 12 11 0 Squencer Header 0000 Sequencer ID Event ID ROC Header 0010 ROC ID Event ID FE Header 0100 FE ID Event ID Channel Header 0110 Channel ID Event ID 0111 Data 0 Data 1 Data 0111 Data ... Data ... Data 0111 Data n-2 Data n-1 Data 1110 Channel Trailer Channel ID DWord Length Event ID Repeat Channels 1100 FE ID Event ID FE Trailer 1 1101 FE ID DWord Length FE Trailer 2 Repeat FEs 1010 ROC ID Event ID ROC Trailer 1 1011 ROC ID DWord Length ROC Trailer 1 Repeat ROCs 1000 Sequencer ID Event ID Sequencer Trailer 1 DWord Length 1001 Sequencer ID Sequencer Trailer 2 Data Package to the Event Builder Ed Hungerford

  33. 2nd Coordinate Readout Possible Methods of 2nd Coordinate Measurements in Wire Detectors1) Induction on the cathode a) Strips (pads) b) Delay lines parallel to the anode wires 2) Anode readout a) Charge division on a resistive anode (NIM A479(02)591) or Cathode b) Signal timing between the straw ends c) Signal rise time Tracking with multiple hits in the detector planes can produce ghost trajectories. A 2nd readout might reduce ambiguities.

  34. Charge Division Readout (IEEE 42(95)1430) L/L ~0.6% Signal Division

  35. Charge Division Issues Charge division might provide a 2nd coordinate readout with resolution on the order of L/L  1%; BUT1) The resolution deteriorates with background rate 2) Reducing the integration gate, implementing base line restoration reduces the collected charge (resolution)3) Maintaining calibration requires special data runs and pulser inputs (automated)4) Careful design of all electronics to reduce noise and termination of lines (frequency dependence) 5) Precision wire resistance and analog preamp 6) Shaping amp is a compromise between noise reduction (very sensitive) and rate handling5) Both ADC and TDC readout7) Charge integration within a time gate

  36. Delay Line Readout NIM A479(02)591 DL = 6.5mm 1.7 m long drift-cell

  37. Straw Delay Line ~1m straw delay line is presently under construction Strip width is 1mm spaced by 1mm Expected time delay for 1m is 45 ns one-way. Differential readout to remove common mode propagation

  38. Delay Line Issues Delay Line Timing might provide a 2nd coordinate readout with resolution on the order of L ~ 5 mm. The time sum equals propagation delay + drift time, better signal stability, and anode wire hit ID’ed. BUT1) Requires additional material2) More difficult to construct3) More electronics to build and install in a limited space4) Capacitive and inductive coupling between channels5) Careful electronic design 6) Calibration

  39. Summary COMET is a Phase I search for coherent, neutrino-less conversion of muons to electron (μ-e conversion) at a single event sensitivity of 10-16 The experiment offers a powerful probe for new physics beyond the Standard Model. The experiment will be undertaken at the J-PARC NP Hall using a slowly-extracted, bunched proton beam from the J-PARC main ring. The Experiment is developing a TDR and refining design details. The experiment has completed a CDR and has Stage-1 approval of the J-PARC PAC. The electronic readout of the tracker (and calorimeter) is challenging, requiring new ASIC development that have low power, excellent timing, reasonable resolution, and rate handling, and are robust. The system design requires on detector digitization, storage, buffering, and latency. The event builder must reconstruct events from asynchronous buffer reads We need expert engineering experience with the technical designs Ed Hungerford

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