4次元飛跡検出器の開発

2020.6.15
宇宙史研究センター
構成員会議

Development of 4D Tracking Detector

LGAD: low-gain avalanche detector
原、中村(KEK)、海野（KEK）、和田(D2)、大鳴(卒業)、植田(M1)2015年度から開発を始めた
科研費B、新学術応募、日米科学協力

Tracking at the LHC-ATLAS
HL-LHC
μ=200

Run1: 2012 1x1033 cm-2s-1 (μ=6)

R=3cm, 5~12cm

Run2: 2017 2.5x1034 cm-2s-1 (μ=66)

HL-LHC: 2027～ 7.5x1034 cm-2s-1 (μ=200)

Run1

Run2/Run3

HL-LHC

Pixel size

50x400 um(B-Layer, L1,L2)(5<R<12cm)

50x250 um (IBL)
50x400 um (B,L1-L3)(3cm, 5<R<12cm)

50x50 um
5 layers(4<R<28cm)

ASIC

FE-I3 (250nm)

FE-I4 (130nm)

ITKpix (65nm)• ピクセルサイズの微細化で対処する• ASICのプロセス細分化で対応できた☛ 空間以外の情報？
2/21

Radiation at hadron colliders
Run1: 2012 1x1033 cm-2s-1 (μ=3)

Run2: 2017 2.5x1034 cm-2s-1 (μ=66)

Radiation environment

HL-LHC: 2027～ 7.5x1034 cm-2s-1 (μ=200)ℒ=300 /fb ⇒ 4000 /fb

300 um thick/74um pitch sensorでの電荷収集量>2x 1016 neq/cm2

電荷収集量の低下：キャリアのトラップ

K. Hara et al, HSTD12厚いセンサー(物質量、トラップのため増えない）▷ 電極間を短くする▷ 電圧を上げる▷ アンプのノイズを下げる
HL-LHCでは▷ ３つとも採用
さらには☛ ゲインのあるセンサー？
3/21

LGADlowgain avalanche detector
A thin highly-doped p-layer provides an internal gain

R&D with HPK since 2015.

Rise time: 0.5 ns
Gain: 10-50~50um

Best performance is at
low gain (10-) ⇒LGAD
Time walk: 1/riseTAPDMPPCLarger gain
⇒wider pulse⇒larger shot noise⇒sensitive to low E γ

LGADThicker active sensor will not improve pulse
amplitude, degrading the rise time

時間分解能を決める主な要素

jitter: noise, 1/riseT“large gain in short time”

4/21

LGAD@HL-LHC ATLAS HGTD
HGTD: high granularity timing detector

HSTD TDR
Heavy flavor tagging
vs Light-jet rejection

前方領域 (2.4<|η|<4.0)のカロリメータ直前
カロリメータでのエネルギー測定

HSTD TDR
Lepton isolation
efficiency

×位置分解能でvtx除外×時間分解
能でvtx除外~1.8mm/vtx

R<0.25/21

LGAD@HL-LHC ATLAS
sensor

ALTIROC ASIC (65nm)

15x15=225 array

Voltage-sensitive amp.
(fixed threshold)
Hit flag
TOT: Time over threshold(40ps/9bit)
TOA: Time of arrival(20ps/7bit)

パッドサイズ：1.3mm□(occupancy~10%)

Testbeam result
45→36psw/o w/ amp. Corr.

6/21

4-D Tracker
ATLAS HGTD: pad-type LGADs
TOF ⇒ Vertex Point

Future Circular Hadron Collider (FCC)
Add time information to each hit Reconstruct tracks using proper time differences
 Help reduce wrong hit combinations and effective
in reducing the track reconstruction CPU⇒ innovation in tracking
Fine segmentation/good timing are both required= 4-D Tracker
7/21

FCC (future circular collider)
100 TeV hadron collider (FCC-hh)
2019 Technical Design Report
LHC ⇒ HL-LHC (2027- 10年間) ⇒8/21

M. Saito (ICEPP) presented atLGAD workshop, Dec 8, 2018
@U. Tsukuba

Tracking at FCC
No time info
μ：200→500
Nsi：４→5

4 pixel layers in default
5 pixel layers in alternative layout

HL-LHC
μ=200

σt=50ps✓ Time information helps reduce degradation for larger μ

9/21

LGAD time resolution

FNAL testbeam2017 TB S. Wada

120 GeV p

3GHz wideband
InGaP HBT

5G/s FADC

10/21

1st segmented
HPK LGADLGAD gain (uniformity)
on n++

80 um pitch
Collimated IR laser
Analog signal r/o withAlibava system

2017 K. Onaru
off n++

This segmentation
is not uniform andnot appropriate for
4D tracker
OK for HGTD
11/21

Boosting LGAD development
2018 LGAD workshop @ Tsukuba (Tokyo)

2019-2022 科研費(原）「高時間分解能を併せもつ高位置分解能4次元半導体検出器の実現」
2019-2020 新学術(中村）「医療機器 TOF-PET に用いる半導体検出器の開発」
2018,19,20 日米科学協力（中村）✓ 細分化された一様性のあるLGAD
2018： TRENCH (S. Wada)
2019： AC-LGAD (K. Onaru)✓ β線を用いた時間分解能測定

5GHz (12bit) FADC

簡便に時間性能評価が可能
Fast amp. (A. Apresyan FNAL/日米）

Onaru, Ueda
12/21

LGAD segmentation by Trenches
TCAD simulation
Parameters tuned toreproduce response of anexisting segmented LGAD

Vertex2019, S. Wada et al.

5um deep, 1um wide

Breakdown characteristics
better for trench

50um pixel

MPPC trenches (HPK hp)

HPK has good experiences of trenches for MPPCs (X-talk suppression)⇒ HV range is different (VMPPC<~60V)

13/21

LGAD segmentation in AC-LGAD
TCAD simulation

HSTD12, K. Onaru et al.
breakdown

P+-HVSignals are read out via AC coupled electrodes
Segmentation of readout electrodes is independent
to the uniform multiplication layer
Concerns: resistivity (doping) of n++ layer
too low ⇒ good gain but signals spread out
too high⇒ good isolation but low gain/signal pile-up

14/21

LGAD segmentation in AC-LGAD
n++: 1/100

conventional

HSTD12, K. Onaru et al.
TCAD simulation

E=105 V/cm
0n++: too highSignal spread tothe neighbors

10n++: optimum
Small spread

Depth (um)

0n++: too low
Signal may pile-up

10

Depth (um)

Uniform gain should be achievable

15/21

Stable LGAD operation
Key point:
Lower operation voltage⇒ Widen the gain region
0n++deeper p+ implantation

10
Secondary Ion Mass Spectrometry@Versailles University (FJPPL)

p+originalmodified

Wider high E-filed region(sufficient gain at lower voltage)

16/21

RD50
Radiation induced change of theeffective doping concentration

Rad-hard LGAD
S. Wada et .al. (HSTD11)

Non-irrad

1x1015 n/cm2“Donor creation” (high Z)“Acceptor removable” (low Z)

M.Moll Vertex2019

BiOi (donor)
BiCi (acceptor)

17/21

LGAD development for bio-science
2019-2020 新学術(中村）「医療機器 TOF-PET に用いる半導体検出器の開発」
TOF-PET

Compton technic

Transparentelectrodes

High speed photo-sensor(medicine, bio-)

511keVavalancheDiscussions with山谷(放医研）
高橋（ICEPP)

Active (50um)
inactive100~250um

SOI project
Scintillator bars (~5x5mm□)
TOF: ~1cm, realized with MPPCs
Improve position resolution with LGAD …
Silicon is not heavy for gamma conversion…

HL-LHC project

LGAD project
18/21

Summary
Finely segmented LGADs as the 4-D detector- Breakthrough device in future high intensity HEP experiments- Unique photo sensor
New (first) HPK AC-LGAD samples have been fabricated
Uniformity (timing, position) to be evaluated
In addition Improve radiation hardness
Development of multi-channel readout amplifiers (w/ FNAL)
Development of ASIC … RD53

19/21