Four Channels Data Acquisition System for Silicon Photomultipliers

Mateusz Baszczyk, Piotr Dorosz, Sebastian Głąb,Wojciech Kucewicz, Łukasz Mik, Maria Sapor

Department of Electronics,AGH – University of Science and Technology,Al. Mickiewicza 30, 30-059 Krakow, Polande-mail kucewicz@agh.edu.plsglab@agh.edu.pl

Agenda

• Fluorescence;• Silicon Photomultiplier description;• Description of previous measurement system;• Four channel data acquisition system;• Results;• Summary;• Future work.

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Why do we measure fluorescence light intensity?

• Dye-labelled cells can be count by fluorescence light intensity measurement;

• At low concentrations the fluorescence intensity is generally proportional to the concentrations of fluorophore.

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Fluorescein and Bio-Tek filters spectra

fluorescein resorufin

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Optical block

Blue LED

S500LLB4G-H+

485/20nm optical filter

1.5 ml cuvette with fluorescein solution

530/25nm optical filter

5mm diameter optical channel

5mm diameter optical collimator

and fiber cable with 940um core

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Silicon Photomultiplier

The idea appears in the late 90-ties:•„Photon Detection with High Gain Avalanche Photodiode Arrays” S. Vasile, P. Gothoskar, R. Farrell, D. Sdrulla•„Silicon avalanche photodiodes on the base of metal-resistor-semiconductor (MRS) structures” V. Saveliev, V. Golovin 6

Structure

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Current - Voltage Characteristic

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Photodiode Operation Mode

1 photon generates 1 electron-hole pair9

Avalanche Operation Mode

1 photon generates 10-200 electron-hole pairs10

Geiger Operation Mode

1 photon generates 105 - 106 electron-hole pairs11

Typical SiPM Parameters

sensL s1020 Hamamatsu S10362-11-025C

Spectral Range (λ) 400-1100 nm 320-900 nm

Peak Spectral Response (λ) 490 nm 440 nm

Breakdown Voltage (Vbr) 28.6 V ---

Operating Voltage (V) 30.6 V 70.82 V

Microcell Gain 106 2.75 · 105

SPM Pixel Active Area Φ 1 mm Φ 1 mm

Number of Pixels 400 1600

Dark Rate (MHz) 0.42 0.3

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Previous Measurement System For Fluorescence

Picosecond 2600C

generator

Cuvette holderwith

specimen

GPAamplifier

QDC device

PC with Labview

application

excitationfilter

emissionfilter

Agilent33250

generator

trigger signal gate pulses

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First Measurement System For Fluorescence

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Acquisition System

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Acquisition System

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Front-end ASIC

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Front-end ASIC

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Front-end ASIC

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Linearity – high gain

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Linearity – low gain

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Measurement results

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Measurement results

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Measurement results

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Measurement results

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Measurement results

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Measurement results

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Light Intensity

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Light Intensity

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Light Intensity

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Without Coincidence

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Coincidence

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Results of fluorescence light measurements

976.6 [pg/ml]61.05 [pg/ml]

y = -572500 x² + 223.6 x + 6458000 – fluoresceiny = -373800 x² + 170.3 x + 14030000 – resorufin

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Influence of Temperature and Bias

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Dark Current Rate

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Influence of Temperature and Bias

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Conclusions

• We have designed, built and optimized readout system for detection of single photons;

• We have tested readout circuit with light and confirmed that it is linear;

• We can distinguish a dozen or so photons and eliminate thermal generation from measurement data;

• System with silicon photomultiplier has a good sensitivity and can be used to measure fluorescence light intensity for fluorescein concentration from 1ug/ml to about 60pg/ml and resorufin at the level of 1ng/ml up to 1ug/ml.

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Future work

• Stabilization system compensating temperature influence on SiPM gain by varying supply voltage;

• Measurements of fluorescent dyes in microbioreactors.

scanning probe

micro-bioreactor

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Thank you for your attention

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