Development of a SiPM readout circuit and a trigger system for microfluidic scintillation detectors Mikhail asiatici 03/07/2014

Overview Project context (short overview) So far In progress LabVIEW interface for oscilloscope and XY table PMT measurements Amplifiers simulation and PCB design PCB manufacturing In progress PCB test Next steps SiPM measurements

Project context - Target system Microfluidic scintillator detector Multiple photodetectors to allow reconstruction of particle tracks with high resolution (60 μm channel pitch) Very low light level (1.65 photoelectrons per MIP, in average) A. Mapelli et al. - Scintillation particle detection based on microfluidics 1/13

project context – sipm vs pmt A. Mapelli et al. - Scintillation particle detection based on microfluidics N. Otte - Silicon Photomultipliers a new device for frontier detectors in HEP, astroparticle physics, nuclear medical and industrial applications 2/13

Project context – Trigger system Sensor photosensitive area Photodetectors Scintillating fibers 3/13

Project context – xy table Stepper motors controller 2 x motorized linear stages in XY configuration 4/13

System overview XY table SiPM A SiPM B PicoScope 6403C C PC LabVIEW Under test USB PMT D ext Trigger(s)/signal(s) 5/13

Labview interface: overview 6/13

Labview interface: features (1) Each channel can be independently Set as signal source, trigger, temperature or disabled Connected to any pulse source (PMT, SiPM, …) Trigger modes Self trigger (on any signal channel) Single external trigger A function generator can emulate a periodic/random trigger Coincidence trigger with programmable coincidence window Online pulse integral calculation and histogram generation Several post-processing options available 7/13

Labview interface: features (2) Waveforms circular buffer Online monitoring of the capture Temperature acquisition Temperature sensor with voltage output XY table interfacement Automatic scan of an array of points Simplified definition of matrices of points Import/export from/to XML file Manual control of the XY table 8/13

Labview interface: features (3) File logging Events in ROOT format Settings and scan points in XML format Automatically created together with the ROOT file Can be read back in LabVIEW to load scan points and/or capture settings Performances Successful capture of up to 37 000 000 events Event rate up to 6 kHz 9/13

Labview interface: pmt acquisitions Tests performed so far: Scintillating tile and coincidence trigger (no NIM module required) Thick liquid scintillator (Davy) Higher event rates (up to 1 kHz instead of 10 Hz) Higher number of events in single acquisition (up to 37 million) Variable integration time 50 ns, single pulse 10 us, multiple pulses (UV LED excitation) 10/13

Pcb: overview Low voltage power supply (4.75 V – 6 V) Optionally -5 V SiPM (SMD package) PicoScope MCX SMD connector LV LV Amplifiers Step-up switching converter Coax cable HV LEMO connector 11/13

PCB: current situation PCB delivered on July 2 Power supply: working 69.8 V to 75.0 V from 5 V source (USB) 12/13

Next steps PCB testing SiPM measures Amplifiers (microScint and INFN) Darkness Microchannels … 13/13

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Amplifiers simulations For SiPM: equivalent model by F. Corsi et al.1 Parameters from one of the devices presented in the paper (SiPM IRST), with Q = e*M ≈ 200 fC (M ≈ 1.25 x 106 for the devices received) Amplifier 1: transconductance amplifier + voltage amplifier (single stage from C. Piemonte et al.)2 with wide-band voltage-feedback op amp (ADA4817) ≈ 10 mV/pe single stage ≈ 100 mV/pe double stage (but slower) Tsettle5% ≈ 50 – 150 ns (trade gain for speed) Very low noise (EIN = 4.4 nV/sqrt(Hz)) 1 F. Corsi et al. – Modelling a silicon photomultiplier (SiPM) as a signal source for optimum front-end design 2 C. Piemonte et al. – Development of an automatic procedure for the characterization of silicon photomultipliers 11/20

Amplifiers simulations Amplifier 2: transconductance amplifier + non-inverting amplifier with wide band current-feedback op amp (AD8000) from F. Giordano et al. ≈ 10 mV/pe single stage ≈ 80 mV/pe double stage Tsettle5% ≈ 40 – 60 ns (fast) Higher noise (EIN = 520 nV/sqrt(Hz)) F. Giordano et al. – Tests on FBK SiPM sensor for a CTA-INFN Progetto PREMIALE demonstrator (presentation) 12/20

Amplifiers performances summary Gain in the order of 10s mV/pe, time constants in the order of 10s-100s ns Amplifier 1 less noisy Amplifier 2 faster 13/20

Amplifiers pcb requirements The PCB is meant as a test board from which possibly derive a definitive configuration, so it is important to ensure the maximum possible flexibility For both the configurations, the signal can be extracted after single or double stage For all of the 4 signal sources, the output can be exctracted before/after a decoupling capacitor Capacitor performs on-board AC coupling, but might results in signal reflections Optional dual supply +/- 5 V as an additional way to produce a signal with no DC component (but maybe decoupling capacitor is enough) All the feedback resistors are potentiometers, to allow gain tuning There is always a certain degree of gain-bandwidth tradeoff Avoid saturation for events with a higher number of photoelectrons Bypassable on-board linear voltage regulator Compare noise with on-board/external voltage regulation 14/20

SMD SiPM adapter board (dimensions in mm) Connector Holes for mechanical support SiPM (Hamamatsu S12571-050P) 15/20

Amplifiers board Jumpers for on-board/external voltage regulation choice SiPM connectors: LEMO Output connectors: LEMO Jumpers for single/dual voltage supply choice Power supply (HV, LV, optional -5 V, GND) 16/20

Power supply board Step-up switching voltage regulator, to avoid the need of an high- voltage supply just for SiPM biasing Output voltage tuning Integrated DAC with serial interface Digital pins available for a possible future integration with e.g. a microcontroller Potentiometer (here not shown) Input voltage range: 4.75 V – 6 V Output voltage range: 64 V – 69 V @ 2 mA Vop of the available SiPM: 66.6 V ± 1.3 V Recommended Vop range: 2.1 V Bypassable additional LC filter at the output to reduce ripple (not shown) Same architecture used for SiPM biasing in the Schwarzschild- Couder CTA Telescope K. Meagher (Georgia Tech) – SiPM Electronics for the Schwarzschild-Couder Telescope (presentation) 17/20

Power supply board LV in (4.75 V – 6 V) Digital interface pins Jumpers to choose DAC/potentiometer for output voltage regulation HV out (64 V – 69 V) 18/20