CSNSM

SPACIROCSpatial Photomultiplier Array Counting and

Integrating ReadOut Chip

S. Ahmad, P. Barrillon, S. Blin, S. Dagoret, F. Dulucq, C. de La Taille

IN2P3-OMEGA LAL Orsay, FranceY. Kawasaki - RIKEN,JapanI. Hirokazu – JAXA, Japan

TWEPP 2012, Oxford 2

Main application: JEM-EUSOJEM-EUSO :

Extremely High Energy Cosmic Ray (EECR) observer onboard of International Space Station

Observing Extensive Air Shower created by the EECRsTotal irradiation dose: 60 krad/5yearsLaunch in 2016

EUSO-BALLOON : Project CNES + IRAP (Toulouse), APC and LAL

supported by the whole JEM-EUSO collaboration 1 PDM with electronics and mechanics as close as

possible to the one of JEM-EUSO SPACIROC : Mapmt readout

Goals: Launch in 2014 Technological demonstrator (PDM + software) Study of the background Detection of an atmospheric shower

Sylvie BLIN

TWEPP 2012, Oxford 3

Front End ASIC requirements

• 64 channels photon counting– Single photon counting 100% trigger efficiency: 1/3 pe (~50 fC when MaPMT

gain=106)– Double pulse resolution : ~10 ns

• => 3 different designs are embedded• Charges to Time (Q-to-T) converters (based on KI02 ASIC –

JAXA/RIKEN)– 8 channels: each for 8-pixel sum preamplifier signals– Pixels charge measurement: 2pC – 200pC

• Data acquisition & Readout to be done within 2.5 µs (GTU)– Readout Clock : 40MHz

• Radiation Hardness By Design : TMR (Triple Module Redundancy) • Power budget : <1 mW/channel

Sylvie BLIN

TWEPP 2012, Oxford 4

Global architecture

Sylvie BLIN

TWEPP 2012, Oxford 5

Photon Counting - Architecture

3 designs: Trig_PA: output directly from preamplifier → lowest dissipation

Trig_FSU : unipolar fast shaper → baseline

Trig_VFS : new optimised fast triggering shaper → fastest design

Multiplexed Trigger to Digital part

2 x 10-bit DAC for threshold

Turn off all blocks.

Sylvie BLIN

TWEPP 2012, Oxford

Q to T: Architecture

Time Over Threshold technique based on a block designed by JAXA/RIKEN (called KI) 8 channels: Each channel input is the sum of 8 consecutive

preamplifier outputs 10-bit DACs for threshold

6Sylvie BLIN

TWEPP 2012, Oxford

Digital Architecture

8 identical digital module for Photon Counting=> 8 clocking counters

1 digital module for Q to T converters=> 8 enable 40MHz counters

9 serial links for data readout + TransmitOn signal

7

Photon Counting Q to T conversion

Sylvie BLIN

TWEPP 2012, Oxford 88

SPACIROC1

– Technology: AMS 0.35µm SiGe

– Submitted in March 2010

– Delivered: Mid-July

– Test: September

– Dimensions : 4.6mm x 4.1mm (19 mm²)

– Power supply: 0-3V

– Naked Die: 1700 chips

– Packaging : CQFP240 (proto)

CQFP160 (Euso-balloon production):

- 100 asics (yield: 85%)

4.1mm4.

6mm

Sylvie BLIN

TWEPP 2012, Oxford

SPACIROC1: Trigger efficiency measurements

9

Photon Counting:

Trig FSU (Baseline)• Gain = 1mV/fC

• Min input = 30 fC• Dispersion: 2.5 DAC unit

Trig_PA• Gain = 0.32mV/fC• Min input = 30 fC

• Dispersion: 1.8 DAC unit

Trig_VFS• Gain = 1.3mV/fC • Min input = 60 fC

• Dispersion: 17.7 DAC unit

Trig_PA : 64 Channel Scurves

Trig_FSU : 64 Channel Scurves

Trig_VFS : 64 Channel Scurves

Sylvie BLIN

TWEPP 2012, Oxford

SPACIROC1: Charge measurements

10

Charge to Time converter

• 8-pixel-sum: Input test: 1.6 – 160 pC

• Simulation: charge up to 250pC

• Measurements: saturation starts at 40pC

ASIC Digital System:• Startbit, Data, TransmissionOn, Parity

Bit• Data output Vhi-Vlo: 1.5V - 0V

KI 8-Pixel-Sum Measurements

KI 8-Pixel-Sum Simulations

Sylvie BLIN

100

65

250pC

160pC

TWEPP 2012, Oxford 11Sylvie BLIN

SPACIROC1 + MAPMT measurements

Photoelectron spectrum

Test setup:

HVPS: K=1000V & Cockroft WaltonMAPMT: Hamamatsu R11265-M64MAPMT Gain: 1.106 (1p.e=0.16pC)

DC LED : λ=378nm

Photon Counting pile up: 25pe/GTU/pixelQ to T range:6.4 -198 pC

Photo Counting and Q to T counter data for input range of 1-180 p.e/GTU/pixel

TWEPP 2012, Oxford

SPACIROC1: Measurement summary

12

• Good behaviour for first prototype

• Good baseline for Photon Counting

• Slow Control cells & Digital modules

working as expected

• Will be used for EUSO-Balloon

(CQFP160)

SPACIROC1 bugs Power consumption:

Due to design bugs, unused component can’t be turned off.

Double pulse separation: 10ns is never reached (due to the power dissipation)

Q to T converter: 8-pixel-sum

Linearity zone is 75% smaller than simulations

Integrated signal swing is 0.7V instead of 1.5V

Consumption

mW/ch

Min input charge (fC)

Double pulse

separationTrig_pa 1.08 30 30

Trig_fsu 1.07 30 36

Trig_vfs 0.96 60 20

Sylvie BLIN

TWEPP 2012, Oxford 13

SPACIROC2– Technology: AMS 0.35µm SiGe– Submitted in November 2011– Delivered in February 2012– Dimensions : 4.6mm x 4.6mm (21 mm2)– Power supply: 0-3V– Packaging: CQFP208 (proto)

Modifications: Trig_pa: add buffer Trig vfs: add turn off switch

improve the discriminator Q to T converter: integrated capacitor values changed

add a reset

Sylvie BLIN

TWEPP 2012, Oxford 14

Average Threshold = 67.8 DAC (1.119V); RMS = 0.8 DAC (~1.3mV)

SPACIROC2: FSU Measurements: 64 channels

FSU50fC

FSUpedestals

Average Threshold = 92.3 DAC (1.06V); RMS = 2.3 DAC (~3.8mV)

Large gap between the pedestals and 1/3 pe → we can easily trig on 1/3 pe

Nice uniformity between channels (rms: 2.3DAC)

Sylvie BLIN

TWEPP 2012, Oxford 15

Average Threshold = 963.7 DAC (2.497V); RMS = 0.8 DAC (~1.3mV)

SPACIROC2: PA Measurements: 64 channels

PA50fC

PApedestals

Average Threshold = 954.6 DAC ( 2.483V); RMS = 1 DAC (~1.65mV)

50fC trigger requirement matched for all channels

(nice separation from pedestals)

Nice uniformity between channels ( rms: 1DAC)

Sylvie BLIN

TWEPP 2012, Oxford 16

Average Threshold =81.44DAC (1.042V); RMS = 0.67 DAC (~1.1mV)

SPACIROC2: VFS Measurements: 64 channels

VFS50fC

VFSpedestals

Average Threshold = 112.25 DAC (1.093V); RMS = 3.48 DAC (~5.7mV)

50fC trigger requirement matched for all channels

(nice separation from pedestals)

Nice uniformity between channels ( rms: 3.5DAC)

Sylvie BLIN

TWEPP 2012, Oxford 17

SPACIROC2: FSU Measurement – Ch32

Gain = 1.23 mV/fCMin Input = 20fC (<<1/3pe)

5sNoise = 7fC

Sylvie BLIN

TWEPP 2012, Oxford 18

SPACIROC2: PA Measurement – Ch32

Gain = 0.563 mV/fCMin Input = 38fC (<<1/3pe)

5sNoise = 7.5fC

Sylvie BLIN

TWEPP 2012, Oxford 19

SPACIROC2: VFS Measurement – Ch32

Gain = 1.18mV/fCMin Input = 20fC (<<1/3pe)

5sNoise = 8fC

Sylvie BLIN

TWEPP 2012, Oxford 20

Double pulse separation

DAC value: 100Injection=1pe * 2

Double pulse separation=26ns

DAC value: 950Injection=1pe * 2

Double pulse separation=28.5ns

DAC value: 120Injection=1pe * 2

Double pulse separation=20ns

FSU: 26 ns

PA : 28ns

VFS: 20ns

Sylvie BLIN

TWEPP 2012, Oxford 21

Q to T(8-Pixel-Sum) - Linearity

Discri input

Discri output

Poor linearity

Not a problem for our application

Only used to detect high signal

=> turn off the mapmt HV

Sylvie BLIN

TWEPP 2012, Oxford

Measurement summary

22

SPACIROC1 ConsumptionmW/ch

Min input charge (fC)

64 channel dispersionDAC unit

Double pulse separation

(ns)Trig_pa 1.08 30 1.8 30

Trig_fsu 1.07 30 2.5 36

Trig_vfs 0.96 60 17.7 20

SPACIROC2 ConsumptionmW/ch

Min input charge (fC)

64 channel dispersionDAC unit

Double pulse separation

Trig_pa 0.74 38 1 28

Trig_fsu 0.87 20 2.3 27

Trig_vfs 0.88 20 3.5 20

Almost everything has been improved

Sylvie BLIN

TWEPP 2012, Oxford

Conclusion

23

The best trigger design will be chosen by the collaboration

Spaciroc1 : demonstrator

Spaciroc2 : JEM-EUSO

Eliminate all power consumption problems

Improve double pulse separation

All trigger designs can be used

Sylvie BLIN

TWEPP 2012, Oxford 24Sylvie BLIN

TWEPP 2012, Oxford 25

SPACIROC1: Mapmt measurements

Test setup:HVPS: K=1000V & Cockroft WaltonMAPMT: Hamamatsu R11265-M64MAPMT Gain: 1.106 (1p.e=0.16pC)

DC LED : λ=378nm

Photon Counting

KI

Photon Counting pileup:30p.eKI range:6.4 -198 pC

Sylvie BLIN

TWEPP 2012, Oxford 26

Photon Counting – Simulations• Triggers for 80 fC input charge (1/2 pe for PMT gain =106)

Trig_FSUVth=1.2vΔt<10ns

Trig_PAVth=2.35v

Δt<5ns

Trig_VFSVth=1.2vΔt<5ns

Sylvie BLIN

TWEPP 2012, Oxford

Digital part waveform

• GTU : 99% duty cycle synchronised to Readout clock falling edge• Each DataOut serial link: 66-bit data (StartBit + Counters Data +

ParityBit)• TransmitOn signal active during data transmission on DataOut links

27Sylvie BLIN

TWEPP 2012, Oxford 28

Photon Counting – Simulations• Triggers for 160 fC input charge (1 pe for PMT gain =106)

Trig_FSUVth=1.2vΔt<10ns

Trig_PAVth=2.35vΔt<15ns

Trig_VFSVth=1.2vΔt<5ns

Sylvie BLIN

TWEPP 2012, Oxford 29

KI 8-Pixel-Sum – Simulations

2.4pC11pC52pC240pC

• Input : 2.4pC – 240pC

Sylvie BLIN

TWEPP 2012, Oxford 30

Q to T (8-Pixel-Sum) - Architecture

Dt=25.15ns

Dt=48.3ns

Dt=59.8ns

Dt=72.59ns

Ddata_ki=1

Ddata_ki=2

Ddata_ki=3

Ddata_ki=4

Discri input

Discri output201ns, 287ns,397ns,

509ns,608ns

Sylvie BLIN