Investigation of the front end electronics for the proton radius - PowerPoint PPT Presentation

Investigation of the front end electronics for the proton radius experiments Alexander Inglessi • PNPI Gatchina TPC Collaboration Meeting • 10 March 2020 • TU Mainz

TPC prototype Active target: gas target + ionization chamber 4 64 8 60 63 Recoil 3 7 59 2 62 56 12 6 58 11 55 1 61 10 5 54 57 9 53 52 16 51 Projectile 15 14 50 13 49 65 17 45 18 46 Z 19 66 47 V 20 21 41 48 22 25 37 42 29 33 23 43 26 38 24 44 34 30 3mm 200mm 27 39 Cathode 31 35 Anode Grid 28 40 32 36

Front-end prototype

SIS3316 VME digitizers ● 16 channels per module ● 25 MHz (40 ns bin), up to 250 MHz ● 14 bit, 5 V (2 V) range ● Int./ext. trigger ● MAW energy/threshold

Individual signal analysis 14000 "signal_b20a75.txt" u 1:2 "signal_b20a75.txt" u 1:6 13800 "signal_b20a75.txt" u 1:7 ● Signal smoothing "signal_b20.txt" u 1:5 13600 13400 13200 ● Peak search 13000 12800 12600 ● Obtaining time 12400 12200 12000 parameters by slope 11800 0 100 200 300 400 500 600 700 800 900 1000 differentiation 12250 "signal_b20a75.txt" u 1:2 "signal_b20a75.txt" u 1:6 "signal_b20a75.txt" u 1:7 "signal_b20.txt" u 1:5 12200 ● Pedestal correction 12150 12100 ● Peak raw signal 12050 integration → energy 12000 11950 400 450 500 550 600 650

Recoil track search ● Initial algorithm 4 64 60 8 implementation 63 3 7 59 2 62 ● Tested in beam 56 12 6 58 11 55 1 61 10 5 54 experiments with 57 9 53 52 16 51 15 14 50 13 different detector 49 65 17 45 18 46 orientation 19 66 47 20 21 41 48 22 25 37 42 29 33 23 43 26 38 24 44 30 34 27 39 31 35 40 28 32 36

Test station at GSI Signal generator MBS, Nyx (CAEN DT5800D) Amplifier

Generated amplifier input signals α -signals. τ GA = 0.5 m s α -signals. τ GA = 0.5 m s I, channel I, channel 1400 6000 1200 5000 Θ = 73.2 deg 1000 Θ = 4.3 deg 4000 800 3000 600 2000 400 1000 200 0 0 0 1 2 3 4 5 6 0 1 2 3 4 5 6 t, m s t, m s 14000 14000 13560 13560 13120 13120 Voltage, ch. Voltage, ch. 12680 12680 12240 12240 11800 11800 19 21 24 26 29 31 19 21 24 26 29 31 t, us t, us

Amplifier shaping time: 1.4 and 0.4 μs 4.3° recoil 73.2° recoil 2e+04 15000 1.4 us shaping 1.4 us shaping 0.4 us shaping 0.4 us shaping 1e+04 14360 1e+04 13720 Voltage, ch. Voltage, ch. 1e+04 13080 1e+04 12440 1e+04 11800 19 21 24 26 29 31 19 21 24 26 29 31 t, us t, us

Results: energy vs. V in (short signal) 88 2.0 E1, AU E2, AU Ehw, AU 70 1.6 Fit to 'E1, AU' Fit to 'Ehw, AU' 53 1.2 35 0.8 Std. dev., AU Energies, AU E1_sigma, AU 18 0.4 E2_sigma, AU Ehw_sigma, AU 0 0.0 0 4 8 13 17 21 0 4 8 13 17 21 Vin, mV Vin, mV 1 AU ≈ 27 keV

Results: integral vs. signal width 2e+04 1.4 us shaping 0.4 us shaping 1e+04 86.1 1e+04 Voltage, ch. 1e+04 85.3 1e+04 1e+04 19 21 24 26 29 31 84.5 t, us ● Energy must be E1 83.7 corrected E (IKAR) E (simple) E (IKAR, left ped. cor.) ● Individual channel 82.9 calibration required 82.1 0 15 29 44 59 73 Theta, ° 1 AU ≈ 27 keV

Results: FADC trigger thresholds 0.4 μs shaping 1.4 μs shaping 1.4 μs, 60PT, 60GT 0.4 μs, 60PT, 60GT 0.1° recoil, "2mv" threshold 0.1° recoil, "2mv" threshold 1.2 1.2 1 1 0.8 0.8 0.1° Count % Count % 0.6 0.6 recoil 0.4 0.4 ~60 keV 0.2 0.2 0 0 0 0.2 0.4 0.6 0.8 1 1.2 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 mV mV 1.4 μs, 60PT, 60GT 0.4 μs, 60PT, 60GT tuning in progress 12.5° recoil, "2mv" threshold 12.5° recoil, "2mv" threshold 1.2 1.2 1 1 0.8 0.8 Count % Count % 0.6 0.6 12.5° 0.4 0.4 0.2 0.2 recoil 0 0 0 0.2 0.4 0.6 0.8 1 1.2 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 mV mV

Shaping time optimization ● time vs. energy resolution ● full integration vs. beam influence minimization ● smaller shaping for beam anode?

Fast FADC readout ● 5 FADCs with 1 Gbit/s Ethernet ● 10 Gbit/s PC link ● ~480 MB/s throughput achieved ● 20x faster than current setup SIS3316 10G Switch Test by SIS GmbH

Conclusions ● High time and energy resolution requirements ● Energy must be corrected ● Thresholds may be lowered ● Time resolution studies with generator are in progress ● Algorithm optimization needed for smaller shaping time (noise filters, possibly higher sampling rate?) ● Goal: final front-end electronics recommendation this year

Thank you!

CAEN DT5800D Digital Detector Emulator ● 2 analog outputs ● 16 bit D/A converter ● 125 Msamples/s ● Constant/ Poisson rate ● 4096 points to store waveforms ● White noise, 1/f noise emulation ● Random Walk (baseline drift) ● Interference generation ● USB, Windows control app

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