1. DAQ Subsystem Christopher Crawford University of Kentucky Robert Grzywacz University of Tennessee April 18 2012 DoE, Germantown MD

2. Data Collection WBS Elements 1.10 Data collection systems $426k + 25% a)1.10.01 Detector Readout Electronics $349k + 23% b)1.10.02 Slow Control $ 4k + 20% c)1.10.03 HV System $ 73k + 36% * Covered by DOE Project funds Detector DAQ in its Faraday Cage (WBS 1.10)

3. WPS 1.10.01 Detector Readout Electronics $349k + 25% Read out waveform (energy + timing) of each pixel2 x 128 ch. offline pulse shape analysis for improved resolution and PID Form e-p coincidences 50 – 750 keV prompt electron 30 keV proton (HV) delayed by 12 – 40 μs TOF Nearest neighbour coincidences for background rejection Energy and Timing Resolution 2 keV energy resolution of electron 12 bit ADC – must sum energy in adjacent pixels and opposite detector 10 ns TOF resolution of proton; 100 ps systematic 100 MHz – detection of initial proton direction in backscattered events HV Optical Isolation 30 kV potential between detectors and ground Scope:

4. Detector Schematic

5. PIXIE-16 Waveform Digitizers trigger logic

6. PIXIE-16 Waveform Digitizers Filter ADC FPGA

7. Trigger and Readout Event / Data rate < 5000/s decay rate in active volume; 600/s protons in upper detector Coincident electron in adjacent pixel (7/127), either top or bottom detector Accidentals from decay products <1% for 40 us coincidence window PIXIE-16 waveform digitizer: 100 MHz sample rate, 12 bit ADC 14 pixels * 1 us * 100 MS/s * 12 bit * 5000 /s = 11 MB/s; 12 TB / 2 weeks Trigger scheme Trigger levels: 1) DIGITIZER threshold, 2) FPGA readout, 3) CPU storage Trigger separately on protons / electrons, form coincidences in software Energy sum trigger for adjacent pixels – detection of lower-threshold events Read out 6 neighboring pixels around trigger Local trigger decisions based on hit information from other modules: main FGPA hits PXI bus trigger lines digitizer FPGA fiber optics readout rear I/O module

8. WPS 1.10.01 Detector Readout Electronics $349k + 25% Design/procure/test prototype systemMar 2012-Apr 2013 Design and construct optical isolation rear I/O module convert existing CAT5 cable to fiber optic FIPPI FPGA firmware upgrades – engineers at XIA Overlapping event readout Low-threshold trigger Main FPGA (trigger) firmware upgrades – XIA Multichannel readout (lookup table) Energy summing trigger Procure remaining channels assemble and test complete systemApr 2013-Jan 2014 Work:

9. WBS 1.10.02 Slow Control $4k + 20% Scope: Record operating conditions of detector - temperatures, pressures, beamline current Control movement of shutters; start/stop DAQ Work: Based on the NPDGamma slow control system - procure computer, and I/O cards - modify software developed for Nab data - test system before delivery to ORNL Schedule: Oct 2013 – May 2014

10. WBS 1.10.03 HV System $73k + 36% Scope: Faraday cage for digitizers, preamp power supplies HV supply and isolation transformer for power Umbilical cord with signals, power, and cooling Work: Design support structure and shielding SNS HV safety review Build cables, testing Schedule: Jan 2014 – May 2015 * This system will be based on similar systems used in aSPECT and aCORN experiments