Kyoto's Ｘ線衛星搭載用SOIPIX検出器
京都大学理学部物理第二教室

宇宙線研究室鶴 剛 (tsuru@cr.scphys.kyoto-u.ac.jp)
論文・国際会議 （黄色は査読論文）
Ryu et al.
Ryu et al.
Tsuru et al.
Ryu et al.
Nakashima et al.
Nakashima et al.
Ryu et al.
Takeda et al.
Tsuru et al.
Nakashima et al.

IEEE NSS 2010, Conf. Record
IEEE TNS 58, 2528 (2011)
IEEE NSS 2011
IEEE NSS 2011, Conf. Record
IEEE NSS 2011, Conf. Record
Physics Procedia 37, 1373 (2012)
IEEE TNS 60, 465 (2013)
IEEE TNS 60, 586 (2013)
SPIE Astro2012
NIM A, Accepted (2013)

XRPIX1-CZ -FI
XRPIX1-CZ-FI
Review
Event-Driven Readout system
XRPIX-ADC1
XRPIX1-FZ-FIXRPIX1b-CZ-FI, Inter-pixel cross-talk
Event-Driven Readout with XRPIX1b-CZ-FI
Review
XRPIX2

20130424_DM_SOIPIX_v2

1

Ｘ線天文をやっています。

2

市川さんと同じ教室で，身内さんがいらした研究室です．
Ｘ線衛星とＸ線CCDカメラを開発して，そいつらを使って(頂いて)，日々宇宙を観測して(頂いて)います．

Astro-E2 「すざく」1706kg
M-V-6 2005/7/10

Astro-H 2600kg
H2A 2015

3

ASTRO-H衛星(2015)搭載用
Ｘ線CCD素子「DAMICと同じ事をや

200μm 完全空乏 0.84g / 1CCDれ」と言われれば「出量産116個実績 (すばる HSC)来ます」が答えです．

6e- (rms) → 3e-実績

しかし，そんな24μm□→15μm□ 実績のは後追いだ！

62mm

115mm
ASTRO-H, the SXI team

cold-end of the TEC is directly connected to the substrateof the CCD, which is mechanically supported by 3 Torlon(polyamide-imide plastic) posts attached to the heat sink. The
heat is transferred through a heat pipe to a radiator panel on thesatellite surface, and is radiated away to space. The radiatorand the heat pipe are designed to cool the base below −40 ◦Cunder the nominal TEC operating conditions. Figure 5 is aphotograph of the inside of base with the frame-store covershield removed. Since the TEC is placed under the CCD, andthe heat pipe is running under the base plate, these are not seenin figure 5.

Suzaku「すざく」 XIS

4生CCD画像

2.5. Radiation Shield

非Ｘ線BGD

On-Board Data ProcessingsSum
pulse h

反同時計数を掛ける SOIPIX

Ｘ線電子
DMも同じ
Spread wit

イメージ上の形状のみで判断している

Spread exc

processing unit) and MPU (main processing unit). Two sets ofAE/TCE are installed in each of two boxes, respectively, called
AE/TCE01 and AE/TCE23. Similarly, 4 PPUs are housedin pairs, and are designated PPU01 and PPU23, respectively.
AE/TCE01 and PPU01 jointly take care of XIS 0 and XIS 1,while AE/TCE23 and PPU23 are for XIS 2 and XIS 3. One
unit of MPU is connected to all the AE/TCEs and PPUs.
The AE/TCE provides the CCD clock signals, controls theCCD temperature, and processes the video signals from theCCD to create the digital data. The clock signals are generated
in the AE with a step of 1/48 pixel cycle (∼ 0.5 µs) according
a micro-code program, which is uploaded from the ground.
The pixel rate is fixed at 24.4 µs pixel−1 . Therefore one line,high

3.1. XIS Electronics
検出感度をリミット
The XIS control and processing electronics consist ofAE/TCE (analog electronics/TEC control electronics) and DE
2桁下げたい@DE is20keV(digital electronics). The
further divided into PPU (pixelcharge split pattern

3.



超巨大BHの探査・研究

can also supply reverse current to the TEC, to warm up theCCD chip in orbit. The CCD temperature may be raised a few
tens of ◦C above that of the base. In practice, the requirement toavoid excessive mechanical stresses due to differential therma
expansion of the copper heat sink relative to the alumina CCD
substrate imposes an upper limit on CCD temperature in thismode. For example, with the heat sink at a typical operating
temperature of −35 ◦C, we have adopted a maximum allow
able CCD temperature of about + 15 ◦C. The CCD temperature
upper limit is higher at higher heat sink temperatures.
The PPU extracts a charge pattern characteristic of X-rays
called an event, after applying various corrections to the digita
data supplied by the AE/TCE. Extracted event data are sent tothe MPU. Details of the event extraction process are describedin subsection 3.3. The PPU first stores the data from its
AE/TCE in a memory called the pixel RAM. In this process
copied and dummy pixels1 are inserted in order to avoid agap in the event data at segment boundaries, to ensure prope
event extraction at segment boundaries and to enable identica
processing of all segments of the data. The raw data from
AE/TCE may include a pulse height (PH) offset from the true
zero level due to dark current, small light leakage through theOBF, and/or an electric offset. Since the offsets depend on
the CCD position and time, offset corrections are also position
and time dependent. To reduce the computing power and timerequired for such corrections, the offsets are divided into twoparts, dark-level and light-leak. The dark-level is the average
output from a pixel with no irradiation of X-rays or charged

PH

Note that this method remove most of the non-X
but some of them still remain in the

宇宙最初期に誕生するFig. 5. The CCD and heat sink assembly installed in the base. Thecover shield is removed in this picture.

low

The performance of any CCD gradually degrades due toradiation damage in orbit. For satellites in low-Earth orbit likeSuzaku, most of the damage is due to large fluxes of charged
particles in the South Atlantic Anomaly (SAA). The radiation damage increases the dark current and the charge transfer
inefficiency (CTI). The XIS sensor body provides radiation
shielding around the CCD. We found from the ASCA SIS
experiment that radiation shielding of > 10 g cm−2 equivalent
Al thickness is required. The proton flux density at 2 MeV on
the CCD chip through 10gcm−2 of shielding is estimated to be∼ 2 × 103 protons cm−2 MeV−1 d−1 in the Suzaku orbit (sameas the ASCA orbit) at solar minimum.

SOIPIX = Silicon On Insulator PIXel sensor
検出部とICの２重シリコン活性層

大きな自由度
用途に最適なデバイス• 厚い検出部＝高い比抵抗 高速IC=低い比抵抗 共存できる．
• バンプ構造(~100μm)なし．余計な質量無し，微細ピクセル，低ノイズ• ADC，DAC，カウンタ等の機能の内蔵
従来：センサー＋読み出しPCB

チップに内蔵• 次世代LSIの有力技術で，民生品半導体工場で製造→高信頼性，低コスト将来の検出器の形

5年2回のMulti Project Wafer (MPW) ラン / PI=新井@KEK
京都大KEK

産総研

大阪大

東北大理研

静岡大

JAXA
北大

Fermi Lab.

LBNL

U. of Hawaii
INP Krakow
U. Heidelberg
Louvain-la-Neuve Univ.
IHEP/IMECAS/SARI China

筑波大

日本の独走状態
・素核 (崩壊点)
・宇宙 (X, FIR)
・物質 (XFEL, PF)・生命 (イメージング
質量分析)

量子イメージングの革新
幅広いサイエンスの革新

6

7“XRPIX” = Kyoto’s Ｘ線衛星用 SOIPIX

ヒットトリガ・ピクセル座標出力できる 宇宙線
X-ray(高エネX-ray

厚い空乏層>300μm粒子)

V_backElectron

各ピクセルに閾値→トリガ出力
アナログ読み出し
サイズ
Energy Band
Spectroscopy
Timing
Function
Non X-ray BGD

Hole

P+CMOS
Readout

CMOS
Readout

CMOS
Readout

V_sig

BPW

scintillator

CMOS
Readout

Time

機上FPGA

撮像領域> 25x25mm2, ピクセルサイズ30-60μm□
0.3-40keV 完全空乏裏面照射型 (>300μm)
Fano limit : 要求<10e- (5σ閾値 0.18keV)→ ゴール1e<1μsec
ヒットトリガ，ヒットピクセル座標出力(軌道上) 5e-5 c/s/keV/10x10mm2 at 20keV (1/100 of CCD)

同じ物 or 簡略化した素子でDM実験可能

2010

2011

1.0 mm

1.0 mmXRPIX1XRPIX1b

XRPIX Series
201282013

4.0 mm

4.5 mmXRPIX2XRPIX2b6.0 mm

6.0 mm

2.4 mm

2.4 mmX-ray imaging area



2.4mm

他のSOIPIX
16.9 x 10.7mm2 w/12μm□

XRPIX
ΔΣ-type
ADC

2.4mm

2.4 mm

A-R-Tec PROPRIETARY/CONFIDENTIAL

59Depletion Depth [um]

XRPIX1-FZ (7kΩcm): Depletion Depth350

FZ : 250μm @ VBB=30V300
250200

CZ : 150μm @ VBB=100V

150
100

+ : Experimental results– : Expected value

50
001020304050Back Bias [V]

6070

80

90

100110• VBB = 30Vで，250μm空乏層を達成済み．
Nakashima, Physics Procedia 37, 1373 (2012)

イベント駆動読み出し

Ｘ線スペクトル

問題なく読み出せている

Cu Kα (8.0 keV)

10Mo Kα (17.4 keV)

1800

ヒット !

1500
Transactions on Nuclear Science- Copy for Review

読み出しクロックCu Count

5 of 62001600
1400

TAKEDA et al.: DESIGN AND EVALUATION OF A SOI PIXEL SENSOR FOR X-RAY TRIGGER-DRIVEN READOUTSCLKADDR[0]ADDR[31]

CA [31 - 0]

2μsec

CA[26]

RA [31 - 0]RA[7]Fig. 12.
9).

Raw X-ray trigger signals recorded by the oscilloscope (c.f., Fig.

Counts

ヒット座標
出力45Column

Row

VTH : 10 mV
40Takedaet al., IEEE TNS 60,586 (2013)
Exposure: 5 sec
8 keV

Trigger Assert Probability

TRIG_OUT

1000
1000

Calibrationh1
Entries0Mean0RMS0800 eV
FWHM

656 eV
FWHM

1200100
Mo Kβ(19.6 keV)

1800
0.9600500

0.8400

Mo Count

FPGA→アドレス

50.7200

00.6 00.50.4080
40120160
Pulse Hight (ch = 244 µV)
4060

80

100

120

140
160
PH [ADU]

VBack = 100 V

0.3
Gain
6.5 µV/e- : 最新CCD並み
-10 ℃
0.2
-30 ℃(rms)
読み出しノイズ 64e
-50 ℃
0.1
閾値
1.2keVee(5σ)
0400
450
500
550
600
650Input Voltage (mV)

最大の改善項目

Fig. 14. Dependence of the trigger output on the input signal at a fixed
threshold voltage of 500 mV. The trigger assert probability is calculated fromal.,10000
2013,A Accepted
the fraction ofNakashima
trigger-on eventset
after
tests atNIM
the corresponding
input

11

秘策(?)あり...
初段のゲインを上げて相対的にノイズを減らす
各ピクセルにチャージアンプ
C=1fF → 160μV/e
ゲイン 25倍2.5e (rms)閾値 (50 eVee) << 300 eVee
間もなく試作品が出来ます．
”イベント駆動 True-CDS”
1e (rms) 閾値 18eVee
2重シリコン活性層を利用
他のデバイスは不可能で，SOIだからこそ実現できる構造
静岡大学電子工学研究所
川人教授との共同研究

Charge Amp
Reset
SWSensor
NodeFeedback
Capacitance

特許関係で詳細は言えません．

まとめ• Ｘ線天文衛星用のSOIPIXを開発しています．
• 反同時計数が出来る，低閾値シリコン撮像分
光器です．

• ほぼ同じ形で，低バックグラウンド暗黒物質直接探査に使えます．

• DAMICを超える事ができます．
必ず良いのを作ります．
是非一緒にやらせてください．

12

Dark Current (e/msec/30.6μm□pixel)
Dark Current (e/ms/pixel)

XRPIX1/1b-FZ-n(2010/12)-FI (7kΩcm) : Dark (Leak) Current 13
106510Black：VBB=30V
Blue ：20V
Red ：10V

FZ (2012)
VBB=20V

104
103

FZ (2010)

102
10

1/100

110-1
10-2
10-3

expectation FZ(2012)
VBB=30V

3e-2
PchNeXT44e-3-50-40-30-20-10010 20
Temperature (degree C)
From 20110516_OKImeeting_SOI_Dark_v5