1 CPTA Center for Prospective Technologies & Aparatus ©2009 – Photonique SA (DMC) APD-Pixel Photo-Diodes for Frontier Detector Systems - GSI Darmstadt.

©2009 – Photonique SA (DMC) APD-Pixel Photo-Diodes for Frontier Detector Systems - GSI Darmstadt - Feb. 20091

CPTACenter for Prospective Technologies & Aparatus

Review of Solidstate Photomultiplier

Developments by CPTA & Photonique SA

Victor Golovin – Center for Prospective Technologies & Apparatus (CPTA)

&

David McNally - Photonique SA



Overview

• n+ p p+ - Visible light applications

• p+ p n+ - UV / Blue light applications

• Outlook



n+ p p+ Structure for Visible Light Applications

Trench Architecture Low optical cross talk High fill / geometric factor Low excess noise Uniform Electric field

10µm Photo from (*):

(*) O. Mineev et al. – Scintillator counters with multi-pixel avalanche photodiode readout for the ND280 detector of the T2K experiment; NIM A 577 (07)



Threshold in photo-electrons equivalent

Optical Cross-Talk

Trench architecture significantly reduces optical cross talk and allows for improved tuning of readout threshold

• No Trench: Crosstalk: 20% … 30%Optical excitation of neighboring cells reduces effectiveness of applied readout threshold

• With Trench: Crosstalk: 1% … 3%Small changes in readout threshold allow for wide range of S/N tuning

Dark

cou

nt ra

te [k

Hz]

(*) Y. Musienko – Advances in multipixel Geiger-mode avalanche photodiodes (silicon photomultipliers); to be published in NIM A (08)

Graph from (*):



Visible Light Sensor Line-Up (2008)

Sensor Area Micro-cell size Micro-cell count Geometric Factor

1mm2 43µm 556 ~60%

4.4mm2 50µm 1764 >70%

9.0mm2 33µm 8100 >60%



Performance Evolution 2005 - 2008

• Improved n+ p junction

• Optimized doping concentrations

• Optimized n+ layer thickness

• Improved trench geometry

• Improved quenching resistor impl.

Evolution of Spectral Sensitivity

05

1015202530354045

350 400 450 500 550 600 650 700 750 800 850Wavelength [nm]

PDE

[%]

2005 - 100V2007 - 20V

L(Y)SO

2005: Vb = ~100V; Vov = Vbias – Vb up to 4V (i.e. 4% of Vb )2007: Vb = ~ 17V; Vov = up to 8V (i.e. 45% of Vb )

2009: Vb = ~ 28V; Vov = >10V Gain ~ 1.4 x 106

(*) 2005: SSPM_040901GV_TO18; 2007: SSPM_0701BG_TO18

Reference (*):Y11



Quenching Resistor

Affects: Cell Recovery Time & After pulsing

Can tune micro-cell quenching resistor value betwee

0.7M and 100M

Fast recovery ~70ns Slower recovery ~10µsec

Modest afterpulsing: Low afterpulsing

<10% in 100ns gate ~1-3% in 100ns gate

Note: Micro-cell capacitance ~100fF



PDE at 515nm vs. Bias Voltage

05

101520253035

35 37 39 41 43 45Bias Voltage

PD

E(5

15 n

m) [

%]

T= 22 CT=-28 C

Gain vs. Bias Voltage

0

0.5

1

1.5

2

35 37 39 41 43 45

Bias Voltage

Gai

n*10

6

T= 22 CT=-28 C

Temperature Stability of Signal Amplitude (I)

AmplitudeSignal = NPhotons x PDE(T) x Gain(T)

(*): SSPM_050701GR

(*) (*)

T = - 28Co | T = + 22Co

Wide Vop range results in reduced slope in the PDE vs. Bias and Gain vs. Bias curves.



Temperature Stability of Signal Amplitude (II)

Amplitude – Temperaturecorrelation is < 1% / Co for bulk of operating range.

( 2009 < 0.5 % / Co )

A wide Vop range over Vb reduces temperature dependence of signal

amplitude

Temperature dependence of Signal Amplituded as function of applied bias voltage

00.20.40.60.8

11.21.4

17 18 19 20 21 22Bias voltage [V]

1/A

dA/d

T [%

]

(*) SSPM_0701BG

(*)



Stability

Accelerated Aging Test

Measurement from (*)

(*) O. Mineev et al. – Scintillator counters with multi-pixel avalanche photodiode readout for the ND280 detector of the T2K experiment; NIM A 577 (07)

30 days at80Co

Uncertainty of data points: ±2 p.e.

260 days at 18 ~ 27Co

Long-term stability test shows no performance degradation over time



Reliability

From sales between 2004 and 2008:

Failure rate of sold SSPMs is < 0.05%

Causes for failure:

• Mechanical: signal pins damaged

• Abuse – wrong bias (circuit)



p+ p n+ (UV/Blue): Evolution 2005 - 2007

• Significantly improved implementation of this structure

• Still fighting against dark counts: 3 ~ 5 MHz / mm2

• Working on wavelength shifter enhanced devices for deep UV applications

Spectral Sensitivity of p+ p n+ Architecture

0

5

10

15

20

25

30

300 400 500 600 700 800

Wavelength [nm]P

DE

[%]

2005: 1mm2

2007: 4.4mm2

T-coeff. of gain < 1% / Co

Excess noise factor < 1.1Rise time < 700ps

(*) 2005: SSPM_050901B 2007: SSPM_0611B1MM

(*)



OutlookSSPM support electronics:

• Amplifiers / Power supplies / Threshold discriminators / Coincidence logic Modular design Available turn-key or under license

SSPMs - Core sensor developments:• Improved sensor packages• n+ p p+ (Visible)

→ Higher cell density with peak PDE 40% → Higher gain→ Noise / Dark-count rate reduction Target ~100kHz / mm2 @ 22Co

• p+ p n+ (UV / Blue) PDE Target ~40% at L(Y)SO peak Sensitivity down to 150nm Reduce dark count rate



Thank you for your attention

Photonique SAch du Grand-Puits 381217 MeyrinSwitzerland

Web: www.photonique.chEmail: [email protected]: +41 22 777 7357 Fax: +41 22 782 3718Skype: photonique_sa





Geometric or Fill Factor

Architecture exhibits sensitivity in all areas not occupied by trench

2006: Micro cell size: 43µm; Fill Factor ~60%2008: Micro cell size: 33µm; Fill Factor >60%

Trench width 4µm

Picture from (*):

(*) Peter Križan, University of Ljublijana & J. Stefan Institute – Presentation at LIGHT07 – Ringberg Castle - Germany

Step size in X/Y: 1µm

Beam spot at SSPM surface: 1σ ≈ 5µm

Low intensity laser beam<<1 photon per DAQ cycle

TDC10ns gate

Select if exactly1 micro-cell fired

SSPM



Sensitivity Enhancement for Blue/UV Light

• Wavelength shifter applied to sensor surface boosts blue sensitivity.

• Technique can be tuned to respective target spectral range

Blue Sensitivity Enhancement

05

10152025303540

350 450 550 650 750Wavelength [nm]

PDE

[%]

StandardBlue- enhanced

L(Y)SO

Work ongoing for:

• Deep UV spectral range / Selective spectral sensitivity• Fast wavelength shifters

(*)

(*) Standard: SSPM_0701BG Enhanced available on ASS_0604BE 4-element linear array



UV-Blue Sensitive Architecture

Reverse doping structure Favours electron propagation towards p+ p junction

First implemented in 2005



Applications - PET (I)

LYSO: 2 x 2 x 10 mm

Source:22Na 511keV

1mm2 visible light SSPM (1) 9mm2 SSPM with W.L.S. (2)

dE/E (FWHM) 18 % 13.5 %Timing resolution (FWHM) 1.0 ns 1.3 ns

(*) Y. Musienko et al. – Study of multi-pixel Geiger-mode avalanche photodiodes as a read-out for PET; NIM A 571 (07) (1): SSPM_0701BG (2): SSPM_0604BE

Mea

sure

men

ts f

rom

(*):



Applications: Radiation Detectors

Scintillation Tiles with MRS-APD readout (START) (*)

(*) All pictures & graphs from: K. Voloshin et al.: Scintillation counter with MRS APD light readout; NIM A 539 (2005)

Cost effective & scalable technique

Working on calorimetric solutions



Applications - PET (II)

LYSO 3 x 3 x 10mm

dE/E (FWHM) 19 % 15 %Timing resolution (FWHM) < 1.0 ns 2.5 ns

2 x 2 element core matrix(3.3mm sensor pitch) of 4.4mm2 visible light SSPMs

with W.L.S.no W.L.S.

Crystal: 4 x 4 x 20mm LYSOSource: Cs137 (662keV)Fibre: Kurray Y11

SSPM Coupling dE/E (FWHM)

• 1x1mm fibre single 16.7%• 1x1mm fibre-double 14.1%

(*) Photo & Measurement taken from talk: Y. Musienko: EuroMedim 2006 - Marseille

From

(*)

1 CPTA Center for Prospective Technologies & Aparatus ©2009 – Photonique SA (DMC) APD-Pixel Photo-Diodes for Frontier Detector Systems - GSI Darmstadt.

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