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

2. 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

3. 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

4. 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

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

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

7. 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

8. Labview interface: overview
6/13

9. 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

10. 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

11. 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 events
Event rate up to 6 kHz
9/13

12. 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

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

14. 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

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

16. Thank you for your attention

17. backup

18. 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

19. 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

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

21. 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

22. SMD SiPM adapter board (dimensions in mm) Connector
Holes for mechanical support
SiPM (Hamamatsu S P)
15/20

23. 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

24. 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 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

25. 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