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HSTD-8, Academia Sinica, Taipei Taiwan, 8th December, 2011

Development of High Performance Avalanche Photodiodes and Dedicated Analog Systems for HXI/SGD Detectors

onboard the Astro-H mission

T.Saito, M.Yoshino, H.Mizoma, T.Nakamori, J.Kataoka (Waseda U.), M.Ohno, K.Goto, Y.Hanabata, H.Takahashi, Y.Fukazawa (Hiroshima U.), M.Sasano, S.Torii,

H.Uchiyama, K.Nakazawa, K.Makishima (U.Tokyo), S.Watanabe, M.Kokubun, T.Takahashi, K. Mori (ISAS/JAXA), H.Tajima (Nagoya U.) and Astro-H HXI/SGD team


Outline

2

1. Introduction2. Development of APD3. Development of analog systems

4. Summary

-CSA for Astro-H-Analog amplifier-Whole system performance

BGO

APDCSA

ADC

Analog amplifierDigital filter


Astro-H Instruments

Astro-H is the 6th satellite of Japanese X-ray observatory series

HXI/SGD detectors employ BGO active shields

3

to be launched in 2014 with the H-IIA rocket wide band observation : 0.3 – 600 keV(four instruments)

we are developing readout sensor (APD) and dedicated analog system for BGO active shields.


BGO Active Shield

4

BGOAPD

reduce backgrounds by anti-coincidence technique

The main detector is surrounded by BGO scintillatorsAvalanche Photodiodes (APD) readout

generating active veto signals to reject cosmic-ray particles and gamma-ray backgrounds

BGO

HXI

Main camera

depth

depth

Electric field

Gain

photon

HSTD-8, Academia Sinica, Taipei Taiwan, 8th December, 2011 5

BGO

APDCSA

ADC



－ Thermal test (silicone or epoxy resin for APD window)－ Radiation tolerance test (60Co, the total dose : 10krad)－ pre-FM APD acceptance test (evaluate 20 pre-FM APD)

APD for Astro-H

6

Development of pre-Flight Model (pre-FM) APD

Screening test EM shield

－ Window material : silicone resin－ Active area : 10 x 10 mm2

－ Capacitance : ～ 400 pF (gain : 50, inc. dedicated cables)－ Dark current : < 0.4 nA (gain : 50 @ － 15 deg)

Flight Model APD screening test ( ～ Apr, 2012)


Elapsed time [hour]

Tem

pera

ture

[deg

]

1h dwell

1h dwell

20 deg/h

1 cycle (10h)

Thermal test

7

silicone or epoxy resin for APD window severe temperature environment just after the launch

thermal cycle test

silicone

epoxy

The number of the CycleRela

tive

light

inte

nsity

[%]

14% Down

50% Down

APD and BGO come unglued? couple each APD with BGO using a space grade silicone adhesive

We selected the silicone resin for the APD window

Comparison of pulse heights


Radiation tolerance test

8

-1 -0.8

-0.6

-0.4

-0.2

0 0.2 0.4 0.6 0.8 1 次の級

05

10152025303540

The

num

ber o

f APD

Difference between Vb [V]

Difference between Vb before and after irradiation

Breakdown voltage Vb did not substantially decrease

60Co irradiation (total dose : 10 krad, ～ 1krad/year)

Although Id increase 6 times, test pulse width increase only 3 keV!

Breakdown voltage Vb decrease? Deteriorate Id and noise performance?

Total dose [krad]

Dark current[nA]

Test pulse width[keV] (FWHM)

0 0.3 10.6

10 1.9 13.2

Performance before and after irradiation

Because capacitive noise is dominant @ －15deg

Test pulse width evaluated by BGO (1x1x1 cm3) + pre-FM APD


-20 -15 -10385

390

395

400

405 pre-FM1pre-FM2pre-FM3pre-FM4pre-FM5pre-FM6pre-FM7pre-FM8pre-FM9pre-FM10pre-FM11pre-FM12pre-FM13pre-FM14pre-FM15pre-FM16pre-FM17pre-FM18pre-FM19pre-FM20-20 -15 -10

0.10

0.35

0.60

0.85

1.10

-20 -15 -100.1

0.3

0.5

0.7

Different changes

pre-FM APD acceptance test

9

Establish how to screen FM APD dark current Id and operation voltage Vr at gain 50 evaluate 20 pre-FM APDs at three temperatures around – 15 degree

Temperature [deg]

Dar

k c

urre

nt I d [

nA]

Temperature [deg]

Ope

ratio

n vo

ltage

Vr (

gain

: 50

) [V]

Bad (>0.4 nA)

high Vr

We will do FM APD screening test in a similar way


APD Dark current

10

Constitution of APD dark current Id

Id = Ids + M * Idb Ids : surface current Idb : bulk current

Leakage path of surface current

Bulk currentpn

π

nTemperature

Curr

ent

Id

Ids

M * Idb

source

① Ratio between Ids and Idb is possibly different② At in-orbit temperature Idb is dominant because of avalanche gain③ If APD has higher Idb, this APD show different Id changes


BGO

APDCSA

ADC



CSA for Astro-H

12

APD capacitance including cables is ～ 400 pF. Capacitive noise is dominant @ － 15deg.

DIP type hybrid IC

CAN type hybrid ICCSA-Hybrid IC evaluation circuit

Charge sensitive amplifier (CSA) specialized for Astro-H

(FM type)

Astro-H CSA need good noise performance


Performance of CSA

13

shaper

Test pulse

CSA

Detector capacitance0 ～ 1000

pF

APD + cablescapacitance

2000 eV

9.8 eV/pF

400 pF (APD + cables) testpulse width : 6 keV (FWHM, Si 60keV)

8x8x4 cm3 BGO testpulse width : 21.7 keV (FWHM)

Noise performance

Convert into active shield performance

Detector capacitance [pF]

Test

puls

e w

idth

[eV

(FW

HM

, Si 6

0keV

)]

Evaluation of CSA assuming APD capacitance ～ 400 pF

good capacitive gradient : 9.8 eV/pF


BGO

APDCSA

ADC


single-stage differential and integrating circuit


Analog amplifierOptimize the best “integrating time constants”

Test

puls

e w

idth

[keV

(FW

HM

, BG

O 6

62ke

V)]

Integration time constant [us]

\ coun

t

ADC channel [ch]

Testpulse137Cs

“the expended time of output veto signal to the main detector” < 5ms

peaking time adjusted by differential filter (τ > 1.3 ms)

Without differential filter

employ integrating time constants 1.0 – 1.2 ms


BGO

APDCSA

ADC

Digital filterAnalog amplifier


0.9 1 1.1 1.2 1.319

22

25

28

1.0us

1.1us

1.2us

1.0us

1.1us

1.2us

CP4417(1us)

ORTEC570(1us)

Whole system performance

17

Performance of active shield system circuit

digital filter : Ohno, M. et al. (2011) HSTD-8

Test

puls

e w

idth

[keV

(FW

HM

, BG

O 6

62ke

V)]

Integrating time constant [us]

Filled marker using analog & digital filter

better than ready-made analog shaper (ORTEC570 & CP4417)

Ready-made shaper

using integrating time constants 1.0 – 1.2 ms

better

1.0 ms (only analog)1.1 ms (only analog)1.2 ms (only analog)1.0 ms (analog & digital)1.1 ms (analog & digital)1.2 ms (analog & digital)CP4417(1.0 ms)ORTEC570(1.0 ms)

Analog & digital filter


Summary

18

APD Thermal test employ silicone resin for APD window Radiation tolerance test passed (60Co 10 krad) pre-FM APD acceptance test establish how to screen FM APD

CSA good capacitive gradient : 9.8 eV/pF 400 pF (APD + cables) testpulth width : 6 keV (FWHM, Si 60keV)

Analog amplifier employ integrating time constants 1.0 – 1.2 ms

Whole system performance achieve a good noise performance (better than ready-made analog shaper)

Future works large pulse response test (proton, Fe), end-to-end test


Backup slides


: time constant

22222 42352 indbnoise . CMkTRIFMIq sds

Analog noise

20

total noise of analog circuit

Capacitive noiseDark current noise : surface currentdsI : bulk currentdbI

: gain of APDM : capacitance of APDinC


-20 -15 -10 -5 0 5 10 15 20 251E-01

1E+00

1E+01

1E+02

pFM4

pFM16

pFM17

pFM19

pFM20

Dark current(-20 ～ +25 deg)

21

-20 -15 -10 -5 0 5 10 15 20 251E-01

1E+00

1E+01

1E+02pFM1

pFM2

pFM3

pFM4

pFM5

pFM6

pFM7

pFM8

pFM9

pFM10

pFM11

pFM12

pFM13

pFM14

pFM15

pFM16

pFM17

pFM18

pFM19

pFM20

Dar

k c

urre

nt [n

A]

Temperature [deg]


CSA Performance inc. Ref.

22

shaper

Test pulse

CSA

Detector capacitance0 ～ 1000

pF

APD + cablescapacitance

2000 eV

9.8 eV/pF

400 pF (APD + cables) testpulse width : 6 keV (FWHM, Si 60keV)

8x8x4 cm3 BGO testpulse width : 21.7 keV (FWHM)

Noise performance

Convert into active shield performance

Detector capacitance [pF]

Test

puls

e w

idth

[eV

(FW

HM

, Si 6

0keV

)]

Evaluation of CSA assuming APD capacitance ～ 400 pF

－ : Astro-H CSA－ : Reference


APMU analog BBM board

Analog amp. board

APMU analog BBM board


時定数 [us] R1[kΩ] R2[kΩ] R3[kΩ] C1[pF] Gain(R2 / R1) offset[V]

1.0 5.1 10 2 100 1.96 0.9

1.1 5.6 11 2 100 1.96 0.9

1.2 5.1 10 2 120 1.96 0.9

1.32 5.6 11 2 120 1.96 0.9

1.5 5.1 10 2 150 1.96 0.9

1.6 5.6 11 2 150 1.96 0.9

1.8 5.1 10 2 180 1.96 0.9

1.98 5.6 11 2 180 1.96 0.9

R1

R2

R3

C1

VR3k.

R3offset 5

19

5V

Parameter

No using differential filter


0.5 1 1.5 270

80

90

100

110

120

130

140

884,analog

typeB,analog

884, 調整ボード

typeB, 調整ボード


Te

stp

uls

e w

idth

(3

×F

WH

M)[

ke

V]

25

＊ testpulse width (3xFWHM, BGO 662keV)

typeB

8×8×4

Without differential filter


twin-T filter

26

twin-T filter for the better analog filter performance equivalent nine-stage integrating circuit

twin-T filter must use a differential filter for peaking time < 5ms

C

noise performance is shown in the next slide

C R4R3R4

5

C21


0.9 1 1.1 1.2 1.319

21

23

25

271.0us1.1us1.2ustwin-T filter1.0us1.1us1.2ustwin-T filterCP4417(1us)ORTEC570(1us)

Performance inc. twin-T

27

Performance of active shield system circuit

digital filter : Ohno, M. et al. HSTD-8

Test

puls

e w

idth

[keV

(FW

HM

, BG

O 6

62ke

V)]


Filled marker using digital filter

better than commercial analog shaper(ORTEC570 & CP4417)

Commercial shaper

Twin-T

using integrating time constants 1.0 – 1.2 ms

better


APD window

28

APDWindow

+ BGO

APD & BGO adhered by DC93-500

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