Time Resolving Characteristics of HPK and FBK Silicon ... › event › 759 › contributions › ... · Materials (MIDEM 2008), Fiesa - Slovenia, 17-19 September 2008 pp.11-22. ISBN

Time Resolving Characteristics of HPK and FBK Silicon Photomultipliers for TOF and PET

ApplicationsG. Ambrosi, P. Azzarello, R. Battiston, G. Di Loren zo*, M. Ionica, and G.U. Pignatel*

INFN – Sez. Perugia – via Pascoli 1, 06123 Perugia*DIEI – Dip. Ingegneria Elettronica e dell’Informazio ne, via G.Duranti 93, 06125 Perugia

AbstractIn Time-of-flight measurements, or Positron Emission Tomography experiments where two gamma rays are emitted in coincidence, the time resolution of the photodetector is of primary importance.

SiPMs are very promising devices for these applications, since their intrinsic response time can be very short, even less than 1 ns. However the actual timing resolution of SiPM is affected by the area

(capacitance) of the device, by the type of electronics used to pre-amplify the signal, by the Dark count rate which is detected as pure noise, and other second order effects like cross-talk and after dark

pulsing.In this work we report the characteristics of different samples of HPK

(Hamamatsu Photonics) and FBK (Fondazione Bruno Kessler) SiPM,

with the pixel size ranging from 40 to 100 micron. In particular, we have

investigated their time response when stimulated with O(100) ps pulsed

laser with wavelength in the range 400-800 nm. SiPM performances are

also compared with that of fast PIN diodes characterized with the same

set-up.

Spectral measurement

Pedestal

2 pixel

1 pixel

References

Cou

nts

Vbias

� VI labview: multichannel automatic acquisition to determine

dark count rate and breakdown voltage of devices.

� VI Labview realized for direct data acquisition from

oscilloscope.

� 407nm and 783nm pulsed laser head as Low Light

Level (LLL) sources for spectral characterization.

� Comparative characterization obtained with SiPMs

placed at three different distances from light source.

� Noise spectrum obtained by acquiring the SiPM

dark signal to identify the one pixel dark count rate

and the measurement system noise.

Background

Linearity

Spectrum

Multi peak

gaussian fit

�The oscilloscope is an Agilent infiniium 54831D with delta

time measure (two channel measure).

�The signal source is a PICOQUANT pulsed laser diode driver

PDL 800-B with heads of 407nm and 783nm.

� the trigger signal is the laser driver sinchronization output.

�Time resolution values obtained like standard deviation of the

gaussian fit.

�Counts-voltage characteristic obtained with program-

mable leading edge discriminator, as an alternative method

to identify the breakdown voltage and choose the optimum

operating overvoltage.

�Example of result of acquisition: dark count rate

characteristics for different overvoltages

discriminator threshold

� Example of single photon spectrum obtained

with a HPK 1mmx1mm 400 pixels@40um SiPM.

� Preamp is an PHOTONIQUE 0604 with gain

18dB@9V.

� Obtained values also fitted with iperbolic

function to verify the correct trend with

distance.

Cou

nts

� Single photon spectra elaborated to

determine the mean value of detected

photons, the testing sistem linearity and the

excess noise factor (ENF).

� Example of FBK irst 1mmx1mm 400pixels@40um single photon spectrum at three

different distances from source.

σσσσ=98ps σσσσ=97ps

� Hamamatsu

HPK 1mmx1mm

� FBK irst 1mmx1mm � FBK irst PIN Diode

(783nm laser)

� The tested SiPMs exhibit energy and time resolution suitable for PET and Fiber particle tracking applications.

� SiPM time resolution is in the range 40-120ps

� Photon resolution is also very good: SiPM are capable to resolve from 1 to a few photons.

� As far as the noise characterization is concerned, we have found that the Counts-Voltage characteristic is a very

effective method to identify the breakdown voltage and to monitoring the dark count rate.

σσσσ=1.328ns

Conclusions�jp.hamamatsu.com

�www.fbk.eu

�G.U.Pignatel “Silicon Photomultiplier: a novel type of photo-detector with single Photon detection capability”

on behalf of the INFN-DASIPM collaboration, 44th International Conference on Microelectronics, Devices and

Materials (MIDEM 2008), Fiesa - Slovenia, 17-19 September 2008 pp.11-22. ISBN 978-961-91023-7-4

�Claudio Piemonte “A new Silicon Photomultiplier structure for blue light detection”, NIM-A 568 (2006) 224