µ-e転換事象の発見に向けて
MuSICとCOMET実験
大阪大学 大学院理学研究科 佐藤 朗
基研研究会2017@京大2017/08/04

内容µ-e転換事象探索実現に向けてMuSIC@RCNPCOMET実験@J-PARC
まとめ

Akira SATO

MuSIC and COMET for μ-e conversion searches2μ-e Conversion Search
- in
What
is
Muon
to
Electron
Conversion?
Whenaμstoppedinamaterial,...
What is Muon to Electron Conversion?

1s state in a muonic atom

1s state in a muonic atom

Neutrino-less muon
Neutrino-lessmuon
Beyondthe SM
nuclearcaptureµ + (A, Z) → e + (A, Z)

nucleusnucleusnucleus −nucleus−µForbidden by the SM, because
Event
Signature: changed to μ-flavor to e-flavor.
the lepton
flavor isµmuon decay in orbit−
Fates of the μ- within
theeSMµ− →ννmuon decay in orbit

nuclear muon capture
−

−

µ
→
e
νν
µ + (A, Z) → ν + (A, Z − 1)−

nuclear muon capture−µµ + (A, Z) → ν µ + (A, Z − 1)
Akira SATO

nuclear capture−

μ-eµ− + (A, Z) → e +− (A, Z) conversion−aEventsingle signaturemono-energetic
Event Signature : :electron
100 MeVa singleofmono-energetic
electron of 105MeV (for Al)
aBackgrounds:
single mono-energetic
inphysics
the SM+ νMeVmasseselectronof backgrounds
100
(1)
μ-e
can inbeorbitoccur(DIO)
via ν-mixing, but
Backgrounds:
ex. conversion
muon decay
expected rate is well below the experimentally(2)accessible
beam-related
backgrounds(1)physics
backgrounds
range.
Rate ~O(10-54)
ex. muonradiative
pion capture,
ex.
decay
inμ-e
orbitconversion(DIO)
Discovery
of
the
is
muon
decay
in
flight,(2) abeam-related
backgrounds
clear
evidenceof new physics(3) cosmic rays, false tracking

beyondthe pionSM. capture,ex.
radiative
muon decay in flight,
in the SM + new physics(3) Acosmic
rays, false tracking
wide variety of proposed extensions to the
SM predict observable μ-e conversion rate.

MuSIC and COMET for μ-e conversion searches3Possible Contributions to cLFVMany models predict a sizable cLFV BR.
~χ 0
i
-

µ

~
lj

N

~
lj

q

-

-

e

µ

q

q

Supersymmetry

-

-

µ

W

e

-

e

q

-

µ

q
Compositenessq

Akira SATO

q

-

-

µ

e
γ,Z,Z’-

e
Leptoquarkst

Two Higgs Doublets

d

d

-

e

t
t

LQ
q

H

Heavy neutrinos

-

µ

-

e

q

q
Anomalous Coupling

MuSIC and COMET for μ-e conversionMuSIC
searches4How to search the μ-e conversion
protons
π production
targetlow energy
μ-μ stopping
targetsignal eE=105MeV

Inject proton beam to a pion production
target to generate a huge amount of muons.
Stop the muons in a stopping target.
Al target for COMET and Mu2e
Muonic atoms are produced
μ lifetime in Al ~ 864ns• 40% μ : decay in the 1s orbit (DIO)• 60% μ : captured to the nulear
Look for the signal electron with E=105MeV.

detector

Akira SATO

Key points:(1) Very intense muon beam
(2) Background suppression
MuSIC and COMET for μ-e conversion searches

5Current limits (90% CL)
BR(μ-Au→e-Au) < 7x10-13 (SINDRUM-II@PSI)
BR(μ-Ti→e-Ti) < 4.3x10-12 (SINDRUM-II@PSI)
BR(μ-Ti→e-Ti) < 4.6x10-12 (TRIUMF)
Precision of coming measurements (90% CL)
BR(μ-C→e-C) < 2.3x10-13 (DeeMe@J-PARC-MLF)• 2016~BR(μ-Al→e-Al) < 7x10-15 (COMET Phase-I@J-PARC-HardonH)• 2019~BR(μ-Al→e-Al) < 6x10-17 (COMET Phase-II@J-PARC-HadronH)• 2021~BR(μ-Al→e-Al) < 6x10-17 (Mu2e@FNAL)• 2021~

10000倍の感度向上

Current Upper Limits and Coming Precisions

1017個のµ-が必要→1年間の実験を仮定すると1010µ-/秒の強度

Akira SATO

MuSIC and COMET for μ-e conversion searches6

: パルスビーム: DC ビーム

世界のミューオン施設
0.2MW
ISIS EM, RIKEN-RAL~6x105µ /s

TRIUMF

J-PARC, MUSE

PSI

1.3MW
~5x108µ /s

0.8MW~4x106µ /s

1MW~3x108µ /s

阪大RCNP, MuSIC 0.0008MW
千倍以上の高効率~7x108µ /s

表 1: 世界の DC ミューオンビーム施設の加速器とミューオンビーム強度

Laboratory/
Beam line
RCNP
MuSIC
PSI
µE4
TRIUMF
M20A
1

Country

Proton beam power

Time structureJapan

784 W(392 MeV, 2 µA )1[1]DC

Switzerland

1.3 MW(590 MeV, 2.2 mA) [3]DC

Canada70 kW(500 MeV, 140µA) [5]DCµ+ yieldper proton beam power [µ/sec/W]

Available µ+ intensity[µ/sec]5 [µ/s/W]
5 [2]
8.5 x 108.5×10

6.7 x6.7×101088[µ/s]

2 2
3.3 x 103.3×10[4]

4.3 x4.3×10
1088

1 1
5.0 x 105.0×10[5]

3.5 x3.5×10
1066

An upgrade program of the RCNP cyclotron facility is in progress to increase 400 MeV proton beam intensity to more than 5 µA.[1]大強度ミューオン源MuSIC

ミューオン生成方式のポイント
従来のミューオン施設
MUSE
proton beam
-1000kWtargetgraphite
t20mm
φ70mm

陽子ビーム

捕獲用電磁石新パイオン捕獲システム 数千倍の生成効率
MuSIC
proton beam
-0.4kWtargetgraphite
t200mm
φ40mm

陽子ビーム
ミューオン
大口径
輸送ソレノイド

厚い標的
スーパーオメガ立体角:400mSr

陽子ビーム

下流施設へ

Akira SATO

捕獲ソレノイド
3.5Tのソレノイド磁場でミューオン

パイオン・ミューオンをビームダンプへ

捕獲

厚い標的&大立体角で捕獲&高効率輸送系
9
MuSIC

世界初のパイオン捕獲システム : MuSIC
大阪大学核物理研究センター(RCNP)

2009年度に完成し、性能試験完了。
Akira SATO

MuSIC

10

MuSIC計画の概要
MuSICとは核物理研究センターリングサイクロトロンからの392MeV陽子ビームを使って、世界最高強度のDCミューオンビーム源を建設し、ミューオン科学を展開する。
目標強度は毎秒108-9μ＠392MeV,1μA陽子ビーム。

大強度ミューオン源の技術的ポイント

世界初の大立体角超伝導パイオン捕獲システムの実現•

従来のミューオン施設に比べて数千倍のミューオン生成効率
ECOミューオン源

世界初の大口径超伝導ソレノイド輸送チャンネル

建設フェイズの第一段階で確認すべき重要事項
ミューオン生成効率の確認（完了）

高放射線環境下でのシステム稼働確認（完了）RCNPにおけるミューオン科学展開（進行中）

新ミューオンラインの建設（2013年度完了）

ユーザーへのDCミューオンビーム供給(2015年度~)
阪大理

佐藤朗：MuSIC

2011/08/09

11

MuSIC@阪大RCNP
Ring Cyclotron

Research Center of Nuclear Physics (RCNP),
Osaka University, Japan

AVF CyclotronWest Experimental HallMuSIC
RCNPの２つのサイクロトロン加速器により最終的に陽子ビームは、運動エネルギー
392MeV,まで加速される。ビーム電流3μAまで可能。
5μA まで増強する計画あり。
MuSICは、一番大きな実験室（西実験室）に設置されている。

Akira SATO

MuSIC

12

MuSIC全体のレイアウト案

Particle physics

Nuclear physics,
material science,chemical ...

Muon storage
ring
Accelerator
R&D
Pion andmuon
transportsolenoid

Build in 2009JFY

Muon beam

Pion capturesolenoid

Proton beam

Superconducting magnets
R&D
Akira SATO

MuSIC

13

MuSIC: パイオン捕獲部

Akira SATO

MuSIC

14

Proton Beam Monitoring on the Target
Graphite Target
phosphor

phosphor

20cm
4cm
Upstream

Downstream

CCD

CCD

Target at the center of the capture solenoid.

3

S. Cook, et. al., Phys. Rev. Acc. and Beam 20, 030101 (2017)

Muon yield @ the solenoid exit
Muon life（Stopping target: Cu）

Muonic X-rays（Stopping target: Mg）
PHYS. REV. ACCEL. BEAMS 20, 030101 (2017)

S. COOK et al.

VI. ANALYSIS METHOD

atom of copper [31], τs ¼ 163.5 % 1.0 ns, were fixed in thefit. The value of T was also fixed to 60 % 5 ns determined
A. Analysis of muon lifetimeby fitting the background noise in a region where no signal
The distributions of t are shown in Fig. 3 for each of theis expected, i.e. high t. The time distribution for an example
five S2 channels for an example data sample (see [30]data sample, with a degrader thickness of 5 mm, is shownfor other samples). Also shown is a fit, NðtÞ, to the data
for each of the five S2 channels in Fig. 3. The fit to thegiven bydata with the function in Eq. (7) is also shown. The fits to""!
!
the data are reasonable with some distributions havingttvalues of χ 2 per degree of freedom of about one as is theNðtÞ ¼ N f exp −þ N s exp −τfτscase for the first channel shown here. Channels 4 and 5 give"!
consistently poor values, worse than channels from 1 to 3,t−ϕþ N b1 sin 2π
þ N b2 ;ð7Þ
and so are excluded from further analysis.
T
The functions for the free decays of positive muons andwhere t is the time in nanoseconds. The four components
decays of negative muons in a muonic atom of copper withcorrespond to the free decay of positive muons, f, the decay
parameters extracted in the fit to the data are then integratedof negative muons in the stopping target, s, a sinusoidal
in order to determine the number of muons in each sample.
background b1, and a flat background b2. The muon
As a cross-check of the method, simulated distributions
decays rates are parametrized with a scale factor N andwere fit with the function in Eq. (7) and the number ofa lifetime τ. The sinusoidal background term, which comes
muons extracted. These values agreed with simply counting
Measured
muon
yield
at
the
exit
of theof 36°
transportsolenoidfrom beam particles (mostly electrons) directly hitting thethe number
real muonsin the simulation.
counters, has a period T and a phase relative to the trigger
The dead time of the DAQ system, due to it being busy,
time, ϕ. It is due to the minor bunching of the protons in
was calculated for each runningmeasurement
configuration from theacceleration, with the rf frequency of the RCNP cyclotron.
number of potential and good triggers. The potential+
The flat backgroundis due topositivetermmuon[µcombinatorial/sec for back400W]± 1.1)scintillator
x 108
triggers were those with a signal(4.2in the upstream
ground of beam particles which fake a signal. Knownand no corresponding signal downstream within the 50 ns
values of negative
the lifetimes, τmuon% 0.0022[9]
veto window. A good trigger (3.6
was defined
as a xpotentialf ¼ 2196.9811[µ-/sec
forns400W]± 0.4)
107
trigger without the system being busy. The dead time varied
and, for a copper stopping target, the lifetime of a muonic

The μ production efficiency shows good
agreements with the design value.
459_D1

600
500

Akira SATO

400

Entriesχ 2 / ndf
Ncu
τ cu
Nf
τf
Nsin
φ
T

459_D295809
1314 / 1239
115.3 ± 9.8
162.5 ± 1.9
155 ± 1.6
2197 ± 0.0
8.864 ± 0.278
56.68 ± 0.71
59.36 ± 0.00

900
800
700

459_D3

Entriesχ 2 / ndf
Ncu
τ cu
Nf
τf
Nsin
φ
T

1498141780 / 1239
369.3 ± 13.4
162.5 ± 0.3
254 ± 2.02197 ± 0.0
14.91 ± 0.35
4.355 ± 0.555
59.37 ± 0.00

250

200

Entriesχ 2 / ndf
Ncu
τ cu
Nf
τf
Nsin
φ
T

33560
1596 / 1239
110.1 ± 7.3
162.5 ± 1.6
81.16 ± 1.06
2197 ± 0.0
3.651 ± 0.156
11.32 ± 1.02
59.37 ± 0.00

MuSIC - Status and Prospects -、2012/09

16

17

MuSIC Pion Capture followed by ...

MuSIC successfully demonstrated a muon intensity =108μ/s is available with a 431W proton beam. It
correspond to ~ 106µ+/s/W and ~ 105µ-/s/W, over a factorof 1000 higher than other muon facilities.
For COMET (elementary particle physics)

combine with 56kW proton beam at J-PARC can make>109µ-/s for µ-e conversion experiments. The COMET
collaboration is building another pion capture system for
COMET at J-PARC hadron hall.

Akira SATO

MuSIC

18

COMET SC magnets for 1010µ-/s beam

• A 90-deg. muon transport solenoid

has been constructed in 2015.
• A 5.5 Tesla pion capture solenoid will
be delivered to J-PARC in 2019.

Akira SATO

MuSIC

19

MuSIC Pion Capture followed by ...

MuSIC demonstrated a muon intensity = 108μ/s isavailable with a 431W proton beam. It correspond to ~106µ+/s/W and ~ 105µ-/s/W, over a factor of 1000 higher
than other muon facilities.
For COMET (elementary particle physics)

combine with 56kW proton beam at J-PARC can make>109µ-/s for µ-e conversion experiments. We are building
another pion capture system for COMET at J-PARC
hadron hall.

For RCNP

The directer decided to start muon program at RCNPMuSIC by extending MuSIC with a muon beamline, which
consists of normal-conducting magnets.

Akira SATO

MuSIC

20

Examples of DC Muon Science at MuSIC
+

±
-

•

-

search for μ→eee (muon LFV) 108-9μ+/sec

DC continuous beam is critical
Materials Science :Needs a long SC
solenoid channel.

μSR (a μSR apparatus is needed) 105-6μ /sec, polarized

Nuclear Physics :nuclear muon capture (NMC)•-

Stage-2

Particle Physics :104-5μ-/sec

nuclear matrix element study for 0ν ββ decaypion capture and scattering
Chemistry :chemistry on pion/muon atoms
104-5μ-/sec
Non-destructive element analysis

A beam line can beconsist of Q,Dmagnets.
Stage-1
MuSIC-M1 beamline has
been constructed!

archaeology, asteroid explorer (Hayabusa-2) 104-5μ-/sec

Accelerator / Instruments R&D(for PRISM/neutrino factory/muon collider) :

•
•
•
•

Akira SATO

Superconducting solenoid magnets
FFAG, RFcooling methods

muon acceleration, deceleration, and phase rotation
MuSIC

21

MuSIC全体のレイアウト案

Particle physics

Muon storage
ring

Nuclear physics,
material science,chemical ...

Build in 2013JFY

Accelerator
R&D
Pion andmuon
transportsolenoid

Build in 2009JFY

Muon beam

Pion capturesolenoid

Proton beam

Superconducting magnets
R&D
Akira SATO

MuSIC

22

A New DC muon beam line: RCNP-MuSIC
Pion capture system
SC solenoids
Muon intensity = 108μ/s
many backgrounds
large beam size, Δp/p

DC muon beam line
NC Q,D magnets

105μ/sProton beam 392MeV, 1μA
from the ring cyclotron
Akira SATO

MuSIC

24

The DC muon beam line in Japan
RCNP-MuSIC-M1 constructed in 2013JFY

Muon beam

Goal of the beam performance
Positive muon：DC-μSR

Triplet-Q

beam size：φ10mm
angle：< 50mrad

intensity：2~4 x 104/sec

Negative muon：nuclear phys. chemi. μ-X
beam size：φ10mm~Φ50mm
angle：< 200mrad

Triplet-Q

intensity：2x104 ~2x105/sec

Triplet-Q
ST2
ST1

Wien filter
gap 15cm
HV: +- 400kV
L=1.8mSpin rotation: 74deg

BM2
BM1

Full operations started from 2017.
Akira SATO

MuSIC

25

MuSIC-M1: Measured μ intensity
×10
140

positive muon
Positive3~1x105µ−/s @60MeV/cwith 1µA proton beam

120

100

80

muon intensity [muons/sec/µA]

muon intensity [muons/sec/µA]

negative muon
Negative
muon

1000

×10

900

3

~7x105µ＋/s @60MeV/cwith 1µA proton beam

800
700

Tuned fordecay muons

600
500
400

60

200

40

100
20
0

10

20

30

40

50 60 70 80 90 100
muon momentum [MeV/c]00Muon yield (μ+/sec for 1μA proton)

300
2.0

Tuned forsurface muons

×105

1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2

10

0

20

20

30

30

40

40

50

60

70

80

p (MeV/ c)

50 60 70 80 90 100
muon momentum [MeV/c]

Notes: Muon was measured a 40cm x 40cm counter with 20nA proton beam, then normalizedwith 1µA. The tuning to get focused beam will be done in this year.
Akira SATO

MuSIC

27

Particle separation and beam size
DC sep. OFF

p=28MeV/c

Beam proﬁle: X

45mm
DC sep. ON
positrons

Akira SATO

muons

Beam proﬁle: Y

DC Sep.

e+/µ+for 28MeV/c

Off

6.8

On(±100kV)

<0.15

45mm

MuSIC

28

Status of Muon Experiments at the MuSIC
20nA E411: Nov. 2015 Done

“Development on non-destructive elemental analysis of planetary materials by using highintensity μ- beam”, K. Terada, (Osaka U.)

G02/E475 : 28-29 May 2016, Impact project

Done“Reaction Mechanism of Muon Nuclear Capture on Pd Isotopes”, by H.Sakurai(RIKEN),

1.1µA G02/E475: Feb.-Mar. 2017 Done

“Reaction Mechanism of Muon Nuclear Capture on Pd Isotopes”, by T.Matsuzaki(RIKEN),

E467: June 2017

Done

E476: June 2017

Done

“Development of muonic X-ray measuring system and precise determination of muon capture
probabilities for iron compounds”, by K.Ninomiya(Osaka U.),
“Measurement of the muon capture on 3He by using of the high intensity continuous μbeam”, K.Takahisa(RCNP),

E490: June 2017 Done

“Muonic X-ray analysis of planetary materials: Development on Isotopic measurement andMuonic X-ray imaging”, K. Terada, (Osaka U.)

E489: in Feb. 2018?

“Muon-gamma spectroscopy for neutrino nuclear responses”, Izyan Hashim (Universiti
Teknologi Malaysia)

E517: in 2018?

← the first official µSR user’s experiment“Study of Novel Superconductivity in Layered Structural Superconductor by means of μSR
technique at MuSIC”, Wataru Higemoto (JAEA)

Akira SATO

MuSIC

29

Pictures for 1.1µA operations
MuSIC µ-element analysis：2017.3.2

Golden Coin (1.1µA, 50MeV/c, 15min.)Members for the muon transmutation

Detector for the Members for the muon

Akira SATO

transmutation

Muonic X-rays from Koban were clearly observedin a short time for the µ-element analysis.

Muon element analysis for a rock.

MuSIC

30

負電荷ミューオンが物質中に停止すると起こる現象
即発

ミューオン原子を形成し、ミューオンX線を放出
µー

~ps

電子

特性X線
ミューオンX線

ニュートリノZ

反ニュートリノ

1s軌道で崩壊
0.8µs
0.1µs

Z

ニュートリノAlの場合: 61%
Z>40で~100%

Z-1
原子核捕獲

Akira SATO

即発

中性子,陽子,重陽子,αなど

即発

γ線

X

X’
X核の寿命

粒子を放出して安定状態へβ崩壊などで
安定状態へ

電子

MuSIC

γ線

31

負ミューオン実験におけるパルスとDCビームの違い
J-PARC-MUSE：パルスミューオンビーム 世界最高強度
数百ナノ秒

ミューオン

ミューオン強度：毎秒108個

繰り返し：40ミリ秒（J-PARC-MUSEの場合）〜〜

ミューオンX線
即発γ線

遅延γ線

パイルアップ、難しい

高統計、高S/N

中性子、陽子など

時間

RCNP-MuSIC：DCミューオンビーム

ミューオン強度：毎秒104~5個

ミューオン

ミューオンX線

繰り返し：10~100マイクロ秒（RCNP-MuSICの場合）

即発γ線

遅延γ線

高統計、高S/N、同時計測

低統計、 低S/N、中性子、陽子など

Akira SATO

時間
MuSIC

32

負ミューオン実験におけるパルスとDCビームの違い
DCミューオンビーム
1x104µ-/s=100µs毎に1個来る

光子

パルスミューオンビーム
2.5x104µ-/s@25Hz=幅100nsのパルスに103個入ってる

µー
試料

中性子

これに遮蔽から制動放射光子が加わる

100µs毎にµ­を1事象ずつ測定できる。

1検出器1ヒットになるように検出器を離す必要がある。

ビームレート(104Hz)でデータ貯まる。
光子や中性子等の同時計測が可能。

25Hz/検出器でデータ貯まる。
同時計測は難しい。

Akira SATO

MuSIC

33

MuSICで究極の負ミューオン
X線γ線分光測定の可能性

μ大立体角Ge検出器：CAGRAíćĊúĊ4Gej1åĆçýćðèíøCAGRA!(Clover!Array!Gamma<ray!spectrometer!at!RCNP/RIBF!for!Advanced!research)
Co<spokespersons:!
9º9>gz}òĈóĊ!
T'ÍfuÎ½ Í!
·ĉ/Ò*ãÖĎÍml<clover@rcnp.osaka<u.ac.jp!
!
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!Ď!
CtÍrPAÎ!Michael!Carpenter!BÎ!Paul!FallonCÎ!Volker!WernerDÎs ÍxEÎnaÍDPEÎFaÍ.EÎÍßÛE!Î¶`Í#UE!Î µÍ>E!Î|ÍR E!Î
¶`Í]-E!ÎHaÍ×ÞâE!Î`Í£ ±E!ÎÍ=E!ÎÍ¦E!Î!
ÍE!Î¥Í;E!ÎÍqFÎC%Í$<FÎvÍ GÎ³ÍS:±GÎmFÍªGÎFaÍNIAÎ?ÍHÎJÍ¦IÎÍ JÎ{Í]0KÍ!
!
A.!c9>Í}>²ÎB.!ANLÎC.!LBNLÎD.!YaleÎ!
E.!9º9>gz}òĈóĊÎF.!9º9>}>Î!
G.#c 9>ĉ%<g>òĈóĊÎH.!"9>ÎI.! ´9>}>ÎJ.!GF9>}>²z}>ÎK.!K9>ĉ9>»}>»ÅÃÄÈÂÃÊÂÅÆ

井手口氏のスライドより
Akira SATORCNPBbj

Æ

MuSIC

35

!
%TargetGe
16cm%
6%clovers%+%Compton%suppression%
大立体角Ge検出器：CAGRACAGRA%status:%Detector%Inventory
shields%from%Tohoku%University.%
from 米,日,中!Inventory%from%Hyper2Nuclei%program%%εph(1MeV)6%%%
BGOコンプトン抑止器付きGe検出器x16台

6%clovers%+%Compton%suppression%
shields%from%Tohoku%University.%
Inventory%from%Hyper2Nuclei%program%+信号読み出しデジタル回路系
at%JPARC%(T.%Koike)%
41mm%
10%clovers%+%Compton%suppression%
70mm shields%come%from%CloverShare%in%USA.%
These%detectors%originally%comprised%
the%Yrast%Ball%at%the%Wright%Nuclear%
Structure%Laboratory%–%Yale%University%(V.%Werner%and%R.%Casten).%%
3%EXOGAM%type%Clover%Detectors%
Detector!geometry!of!CAGRA!for!Geant4!simulaFon
from%IMP,%China%
2015/11/08

JCNP2015

target<detector!
142mm
distance
142.8mm
beam!axis

Akira SATO

at%JPARC%(T.%Koike)%%
10%clovers%+%Compton%suppression%
shields%come%from%CloverShare%in%USA.%1770
These%detectors%originally%comprised%
the%Yrast%Ball%at%the%Wright%Nuclear%
Structure%Laboratory%–%Yale%University%
Dr.%Y.%Fang%↔%IMP
• 16!Clover!Ge!detectors!in!
(V.%Werner%and%R.%Casten).%the!CAGRA!clover!array!

% eam
B
structures!of!the!clover!detector!
3%EXOGAM%type%Clover%Detectors%
Beam
70mm
from%IMP,%China%
2015/11/08
JC

135°

90°

142.8mm

45°

respect!to!the!
beam!axis



Dr.%Y.%Fang%↔%IMP

JCNP2015



MuSIC

36

Absolute!photo!peak!eﬃciency!of!CAGRA!
大立体角Ge検出器：CAGRA

Simulated!eﬃciency!with!a!correcFon!factor

光電ピークの検出効率（シミュレーション）
25!

before!add!back!eﬀ[%]!

photo#peak#eﬃciency#[%]#

20!

aler!add!back!eﬀ[%]!

15!

Energy#(MeV) W/O#Addback W/#Addback

10!

1!

4.55!%

6.27!%

2.5

2.10!%

3.28!%

5!

0!
0!

500!

1000!

1500!

Energy#[keV]#
Akira SATO

2000!

2500!

* Add back: 各結晶のエネルギーを足し合わせること
MuSIC

37

High2rate%capabili
fast%digital%DAQ%sy
stands%for%10%Ome
High2rate%capability%using%%
fast%digital%DAQ%system%
beam%intensity:%2p

CAGRA@RCNPCAGRA%Array

stands%for%10%Omes%stronger%%beam%intensity:%2pnA%→%20pnA

CAGRA%Array

3%IMP%Clovers%%
mounted%at%90°

3%IMP%Clovers%%
mounted%at%90°

Akira SATO

2015/11/08

JCNP2015

MuSIC

38

RCNPでのCAGRA実験キャンペーン
井手口氏のスライド

2015年
6実験

2016年
7実験

終了

Akira SATO

10月~12月

201X年＠with MuSICキャンペーンをやりませんか？

MuSIC

39

MuSIC-M1: µSR spectrometer
MuSIC-M1

Mini-cryo system

n
o
u
M

µSR spectrometer (from KEK)
Max. B field:* Longitudinal = 4.0 kG* Transverse = 365 G
Active collaboration with KEK/J-PARC/JAEA muon group
AkiraMuSIC-M1
SATO
forand µSR measurements.

MuSIC

40

COMET SC magnets for 1010µ-/s beam

• A 90-deg. muon transport solenoid

has been constructed in 2015.
• A 5.5 Tesla pion capture solenoid will
be delivered to J-PARC in 2019.

COMET実験@J-PARC

Akira SATO

MuSIC

41

How to search the μ-e conversion
protons
π production
targetlow energy
μ-μ stopping
targetsignal eE=105MeV

Inject proton beam to a pion production
target to generate a huge amount of muons.
Stop the muons in a stopping target.
Al target for COMET and Mu2e
Muonic atoms are produced
μ lifetime in Al ~ 864ns• 40% μ : decay in the 1s orbit (DIO)• 60% μ : captured to the nulear
Look for the signal electron with E=105MeV.

detector

Akira SATO

Key points:(1) Very intense muon beam (by MuSIC)(2) Background suppression
MuSIC and COMET for μ-e conversion searches

42

Type
BackgroundEs
Physics
Muon decay in orbit
Backgrounds
ofestimatedμ-econversion
searchTable
30: Physics
Summary of the
background
events fora single-event sensitiv
Radiative
muon capture−11
proton extinction
factorof
3
×10
Physics
Neutron. emission after muon capture
Physics
Charged particle emission after muon capture
Type
Es
Prompt Beam Background
Beam electrons (prompt)
Prompt Beam Muon decay in orbit
flight (prompt)
Physics
Prompt Beam Radiative
Pion decaymuon
in flight(prompt)
captureIntrinsic Physics
Prompt Beam Neutron
Other beam
particles
physics Physics
emissionafter(prompt)
muon capture
Prompt Beam Charged
Radiativeparticle
pion capture(prompt)
Physicsemission after muon capture
Delayed Beam
Beam Beam electrons (prompt)(delayed)
PromptDelayed Beam
Beam Muon decay in flight (prompt)(delayed)
PromptBeam
Delayed Beam
Beam Pion decay in flight (prompt)(delayed)related Prompt
Delayed Beam
Beam Other
Radiativepion
capture(prompt)(delayed)
Promptbeam
particles
Delayed Beam
Beam Radiative
Anti-proton
inducedbackgrounds
Promptpion
capture(prompt)
Others Beam Beam
Electronsfrom cosmic
ray muons
Delayedelectrons(delayed)
Total Beam Muon decay in flight (delayed)
DelayedDelayed Beam Pion decay in flight (delayed)
Delayed Beam Radiative pion capture (delayed)
Delayed Beam Anti-proton induced backgrounds
OthersElectrons from cosmic ray muons
Akira SATO

MuSIC and COMET for μ-e conversionMuSIC
searches43

Background
1 : Decay
in orbit
What is Muon to Electron
Conversion?
Neutrino-less muon
nuclear capture

1s state in a muonic atom−

nucleusnucleusµ−muon decay in orbitµ − → e −ννnuclear muon captureµ − + (A, Z) → ν µ + (A, Z − 1)−

µ + (A, Z) → e + (A, Z)
Event Signature :a single mono-energetic
electron of 100 MeV
Backgrounds:(1) physics backgrounds
ex. muon decay in orbit (DIO)(2) beam-related backgrounds
ex. radiative pion capture,muon decay in flight,(3) cosmic rays, false tracking

To distinguish the signals from the DIO backgrounds,
electron energy must be reconstructed with suﬃcient
resolution. To achieve SES of 10-16, σe < 300keV.
Akira SATO

MuSIC and COMET for μ-e conversionMuSIC
searches44µ−followed by charged particles produce e

Background 2 : Radiative pion capture

When π- stopped in the stopping target might emit e- with Ee<139.6MeV.
We adopt three solutions to suppress this BG.

kgrounds
−
′
−
+
Mu2e
Structure
π + Timing
A→γ+
A, γ →e +e
−
+
−
′
Mu2e
beam
timingπ +A→e +e +A
1695$ns$−
POT pulse stopping target
e scattering oﬀ a muon
 arrival/decay time ( × 1M )−−µ arrivaltime ( × 400 ) eµ decays in flight toproduceµ decay/capture time ( × 400 )−−π decays in flight to produce e−neutrons hit material toSignal
producewindow e−p hits material to produce e- Boston, Fermilab, NIU, Purdue, Rice

0.08

0.07

-

0.06

-

0.05

-

0.04

0.03
0.02

0.01
0

0

200

400

600

800

1000

1200

1400

1600
1800
Time (ns)

1. •PutBya utilizing
long transfer
line proton
before beam
the stopping
target signal
a pulsed
and a delayed
2. Waitfor ~ 700ns
to openprompt
the signal
window. by ~1012.
window
can suppress
backgrounds-12~10-11.
3. Make pulsed proton beam with extinction level < 1010
Akira SATO

– Must also suppress out-of-pulse protons by > 10 relative to
MuSIC and COMET for μ-e conversionMuSIC
searches 45
in-pulse protons

COMET and Mu2e
Chapter 1: Executive Summary

COMET @J-PARC
Production
Target•Pion Capture Section

Pion Capture Section

A section to capture pions with a largesolid angle under a high solenoidal
magnetic field by superconducting
maget

A section to capture pions with a largesolid angle under a high solenoidal
magnetic field by superconducting
maget

Production
Target1-3

Mu2e @FNAL

Design and construct a facility to house the Mu2e detector and the associatedinfrastructure (see Figure 1.2). This includes an underground detector enclosureand a surface building to house necessary equipment and infrastructure that can beaccessed while beam is being delivered to the detector.

Pion-Decay andMuon-Transport Section
A section to collect muons fromdecay of pions under a solenoidal magnetic field.

Stopping
TargetDetector Section
A detector to search formuon-to-electron conversion processes.
Stopping
TargetDetector Section
A detector to search formuon-to-electron conversion processes.

Pion-Decay andMuon-Transport Section
A section to collect muons fromdecay of pions under a solenoidal magnetic field.

Figure 1.1. The Mu2e Detector. The cosmic ray veto, surrounding the Detector Solenoid is notshown.

COMET Phase-I :COMET Phase-II :Mu2e :

physics run 2020-

physics run 20192021-

physics run 20192021-

BR(μ+Al→e+Al)<7x10-15 @ 90%CL

BR(μ+Al→e+Al)<6x10-17 @ 90%CL

BR(μ+Al→e+Al)<6x10-17 @ 90%CL*8GeV-3.2kW proton beam, 12110days
days*8GeV-56kW proton beam, 2 years*8GeV-8kW proton beam, 3 years*90deg. bend solenoid, cylindrical detector*180deg. bend solenoid, bend spectrometer,*2x90deg. S-shape bend solenoid,*Background study for the phase2transverse tracker+calorimeter

straw tracker+calorimeter

Design of the both experiments are based on the MECO@BNL experiment
Figure 1.2. Depiction of the above-grade portion of the Mu2e facility.

Akira SATO

Mu2e is integrated into Fermilab’s overall science program that includes 46
many
MuSIC and COMET for μ-e conversionMuSIC
searches
experiments that use the same machines and facilities, though often in different ways.

COMET Staged Approach (2012~)
COMET

COMET @J-PARC
COMET Phase-I
COMET Phase-II
Production
TargetPion Capture Section

Pion Capture Section

A section to capture pions with a largesolid angle under a high solenoidal
magnetic field by superconducting
maget

A section to capture pions with a largesolid angle under a high solenoidal
magnetic field by superconducting
maget

Production
TargetPion-Decay andMuon-Transport Section
A section to collect muons fromdecay of pions under a solenoidal magnetic field.

Stopping
TargetDetector Section
A detector to search formuon-to-electron conversion processes.
Stopping
TargetDetector Section
A detector to search formuon-to-electron conversion processes.

Pion-Decay andMuon-Transport Section
A section to collect muons fromdecay of pions under a solenoidal magnetic field.

COMET Phase-I :Akira SATO

MuSIC and COMET
for μ-e conversion searches 47
COMET Phase-II:

-17
Key Points of COMET Phase-II (S.E.S 10 )Pion Capture Section

Production
TargetA section to capture pions with a largesolid angle under a high solenoidal
magnetic field by superconducting
maget

Detector Section
A detector to search formuon-to-electron conversion processes.
Stopping
TargetPion-Decay andMuon-Transport Section
A section to collect muons fromdecay of pions under a solenoidal magnetic field.

COMET Phase-II :physics run 20192020BR(μ+Al→e+Al)<6x10-17 @ 90%CL*8GeV-56kW proton beam, 2 years*180deg. bend solenoid, bend spectrometer,transverse tracker+calorimeter

Akira SATO

Intense Pulsed Proton Beam
8GeV-56kW (2x107 sec)
width~100ns, separation>1μs
Extinction level < 10-11 reduce beam related BG
Pion Capture Solenoid
5T superconducting
1011 μ-/sec
Long Transport Solenoid
eliminate
L >10mμ (>75 MeV/c)
Curved 180deg Solenoid energetic
and pionsThin Stopping Target
improve
Al 200μm x 17
e- energy resolution
Electron Spectrometer
Curved Solenoid
reduce detector hit rate
Low-mass Tracker
Straw chamber
improvee- energy resolution
in Vacuum
MuSIC and COMET for μ-e conversionMuSIC
searches48

-15
Key Points of COMET Phase-I (S.E.S 10 )Pion Capture Section

Production
TargetA section to capture pions with a largesolid angle under a high solenoidal
magnetic field by superconducting
maget

Pion-Decay andMuon-Transport Section
A section to collect muons fromdecay of pions under a solenoidal magnetic field.

Stopping
TargetDetector Section
A detector to search formuon-to-electron conversion processes.

COMET Phase-I :physics run 2017BR(μ+Al→e+Al)<7x10-15 @ 90%CL
110
days*8GeV-3.2kW proton beam, 12
days*90deg. bend solenoid, cylindrical detector*Background study for the phase2

Akira SATO

Intense Pulsed Proton Beam
8GeV-3.2kW (110 days)
width~100ns, separation>1μs
Extinction level < 10-13 reduce beam related BG
Pion Capture Solenoid
5T superconducting
1011 μ-/sec
Long Transport Solenoid
eliminate
L >10mμ (>75 MeV/c)
Curved 90deg Solenoid energetic
and pionsThin Stopping Target
improve
Al 200μm x 17
e- energy resolution
Electron Spectrometer
Curved Solenoid
Low-mass Tracker
Cylindrical drift chamber

MuSIC and COMET for μ-e conversionMuSIC
searches49

e-I Muon Beam
Goal of COMET Phase-I

Background
Study for COMET Phase-II
almostsame
direct measurement of potential background sources for the full
COMET experiment by using the actual COMET beamline
neconstructed at Phase-I
10-5/proton
Search for μ-e conversion
10-7/protona search for μ−−e− conversion
at intermediate
sensitivity which
BackgroundStudies(only 90
degreewouldbebend)more than 100 times better than the SINDRUM-II limit

Detector• measure almost all backgroundsources• muons, pions, electrons,
neutrons, antiprotons, photons• same detector technology used in
COMET Phase-II• SC spectrometer solenoid• straw tube transverse tracker• crystal calorimeter• particle ID with dE/dX and E/P

Detector for μ-e search

Akira SATO

schematic layout    
   


  

  ! 

    


    
  

Detector for BG study
aim to know the known BG &aim to know the unknown BG

MuSIC and COMET for μ-e conversion searches

50

Background Study

Background Studies

Measure almost all
backgroundlayout• measurealmost schematic
all backgroundSourcessources• muons,
electrons,muons,pions,pions,
electrons,
neutrons,
antiprotons,
photons
neutrons,
antiprotons,• samedetector technology used inphotons
COMET Phase-II
Samedetector
technology• SC spectrometer solenoid
COMET
Phase-II•usedstrawintube
transverse
tracker
SC spectrometer• crystalcalorimeter solenoid• particle
ID tubewith dE/dX
and E/P
straw
transverse
trackercrystal calorimeter
Particle ID with dE/dX and E/
PAkira SATO

schematic layout    
   


  

  ! 

    


end of the
90 deg solenoid    
  

aim to know the known BG &aim to know the unknown BG

MuSIC and COMET for μ-e conversion searches51

6. COMET
Muon Beam
Phase-I Muon Beam Line

Layout of COMET Phase-I

pion production
systemdetector systemmuon transport system

COMET Phase-I detector：

COMET muon beam-line：

Figure 26: Overview of the COMET Phase-I Muon Beam line.

About 1016 muons are stopped in

6x109 muon/sec with 3kW beam
the target.
Electronµ-eline consists of a section for pionproduced.
ThehighestThe COMET
Phase-I
muonfrombeam
production
andworld
capture,a muonconversion
will bemeasuredintensity.in the following
transport
section anda muoncollimation section;. These three elements are descibedsections. At the ‘downstream’ end of the muon beam line is the detector solenoid. The schematiclayout of the COMET Phase-I muon beam line is shown in Fig. 26.
Akira SATO

MuSIC and COMET for μ-e conversion searches52to reduce protons emitted from nuclear muon capture, a cylindrical absorber that is also made CFRP
will be placed concentrically with respect to the CDC axis. A preliminary thickness of the proton
absorber is 0.5 mm. 13 14

CyDet (Cylindrical Detector):
COMET Phase-I : Detector (CyDet)
LayoutSuperconducting coils

CDC inner wall

CDC

CDC outer wall

CDC endplate

Proton absorber

Stopping target

1577.3

1610

835

900

864

360

250

107.5

127.5

496

1490.3

muon

1973

300

Beam duct

Collimator

Vacuum window
Akira SATO

Trigger hodoscope

Shielding

3210

Cryostatunit : mm

Return yoke

MuSIC and COMET for μ-e conversion searches

53for COMET Phase-I

Event selection
Value
Geometrical acceptance 0.24
Momentum selection
0.74
Timing selection
0.39
Trigger and DAQ
0.9
CHAPTER 8. SIGNAL SENSITIVITY AND BACKGROUNDS
Total
0.06

COMET Phase-I : S.E.S.

Comments
tracking eﬃciency incl
104.1 MeV/c < Pe <106same as COMET
same as COMET
100• Single
event sensitivity
Singleevent
sensitivity
SignalEvent
Sensitivity(SES)
Table 8.1: Breakdown of the µ −e conversion signal acceptance per stopped muon for−−

A numberof muons stopped at the muon stopping target is estimat
the case of trigger counters of 5 mm
thickness.
proton from the COMET G4 simulation program, as mentioned in Cha−−
of Nµstop = 5.8 × 1015 (= 0.0023 × 2.5
Event selection a total number
Value of muon stopped
Comments
It corresponds
to 5.8× 109 muons
stopped/s.
Geometrical
0.24
tracking
eﬃciency
includedµ acceptance
cap
e
By
using
these
numbers
thus
obtained,from Eq.(8.1), the single
0.74 104.1 MeV/c < Pe <106 MeV/c
Figure 164: Eﬃciency of the time window cut for aluminium as a function of the end timeMomentumof the timeselection
window.
Timing selection given by 0.39
same −
as COMET−
The width of the proton pulses of 100 ns is included.
B(µAl → e + Al) = 3.1 × 10−15 .
μTrigger and DAQ
0.9
same as+COMETμThe 90 %0.06
confidence upper limit with zero background events is given
Total
16

for COMET Phase-I
B(µ + Al → e + Al) ∼

1

N ·f

,

·A

N is a number•ofmuonsin the muontarget.
It is target.
N stopping
is a numberof stoppingmuonsstoppingin the muon
stopping
15 muons.Phase-I
1.23x10muons.
SignalSensitivity
for
COMET
is
8.7x1016.1.5
Net
Acceptanceofsignals• Single event sensitivity
B(µ + Al → e + Al) < 7.2 × 10 .
9 stopped
8GeV,
3
kW
protonbeam
power,
days•
5.8x10µ/swithwith
3 kW
protonpower,
with
1.5x10•
numberof 110muons
stoppedat the running.
muon beam
stopping target
is estimated tobe 0.0023
per
with
CyDet
It is assumed that the eﬃciencies of trigger, DAQ, and reconstruction areAabout
0.8
for each.
From
8.2.2
Signal
Acceptance
for
COMET
Phase-I
1 = 0.043
protonfrom the COMET G4 simulation program, as mentioned in Chapter 4. From these, Tran
− for the µ N−
the DIO
these, the net acceptance→eN
conversion
signal,A
is obtained.
Theelectrons is presented in Section 17.2. In this study, the mom
secrunning.
a totalnumber ,ofis
muon
stoppedof N aluminum.
= 5.8 × 10 (= 0.0023 × 2.5 × 10 ) is obtained.
Detector
B(µ
+
Al
→
e
+
Al)
∼
f
is
a
fractionofmuon
capture,
which
0.6
for
cap
P < 106.0 MeV/c, where P is the momentum of electron, is determ
breakdown of the acceptance is shown in Table 28.
It corresponds
to 5.8 × 10 muons stopped/s.
Nµ ·offcap·
Ae
The transverse
trackerdetectormay
haveless geometrical
coveragesin
Accordingto this study,
thecontamination
fromelectrons•fisafraction
muon
capture,
which
0.6
for
aluminum.
By using thesenumbers
thus obtained,
fromisEq.(8.1),
thesingleevent DIO
sensitivity
is of 0.01
cap
Signal
Acceptance
Ae is the detector acceptance, which
is 0.043.
only events
theconversion
downstream
event detectsensitivityof the comingµ N →intoe Nof hemisphere.
3.1 × 10 .Detailed
given byto estimate geometrical acceptance will be made soon, together with t• Aeofisthe detector
acceptance,
which
0.06.
B(µ
+ Al → e is
+ Al)
= 3.1 × 10 .
(8.2)
The
transverse tracker detector
has a 32%
is less tha
Breakdown of theµ stopping
N → e N conversion
signal acceptance.
• Nμ Tableis a28:number
muonsin the muon
stopping
target.
It coverage. This
The 90 % confidence upper limit
zero backgroundgiven by hemisphere seen fromtwicewithbecauseof the use ofevents
only isdownstream
15
Event
selection
Value
Comments
target. Trigger and analysis eﬃciencies have not been estimated in a reis 8.7x10 muons.
B(µ+ Al→ e thus+ Al)
7.2 × 10.
these
setup,
we <supposeconservatively
10% in total(8.3)
in either cas
Geometrical acceptance
0.37
9
6
17
15
sensitivity
canbecalculated
from
these
assumption;• 5.8x10
stopped µ/swith 3
kWprotonbeam
power,
with101.5x10Track quality cuts
0.66
B(µ
+
Al
⇥
e
+
Al)
=
3.3
3.1
for COMET Phase-I Transverse Tracker
Momentum selection
0.93 103.6 MeV/c < P8.2.2<106.0Signal
MeV/cAcceptance• 1/(2 × 10 × 0.71 × 0.1) = 0.7 × 10
sec
Detector
Timingrunning.
window
0.3
700 ns < t < 1100 ns
for the cylindrical shape17
detector option, and15
eﬃciency
0.8
B(µ+ Al The⇥transversee tracker+isAl)<
7×aluminum.
10(90%C.L.)
6detectormay
haveless ×geometrical• fTrigger
isafractionofmuon
capture,
which
0.6
•for
1/(2
10
0.32 × 0.1)coverage= 1.6 × since
10 the detector cancap
DAQ eﬃciency
0.8
detect only events coming into thefor
downstream
hemisphere.
Detailed
simulation studies
the transverse
tracker detector
option.
to estimate geometrical acceptance will be made soon, together with tracking eﬃciencies.
eﬃciency acceptance,
0.8• ATrack
thedetectorwhich
is 0.06.These has
e isreconstruction
The transverse tracker detector
a 32% coverage.
Thisupper
is lesslimits
than theformercorrespondto 90% C.L.
of 1.6× 10 about
and 3.7 × 1
Total
0.043
−

−

−

µ-e

stop
µ

e9

−

−

−15

15

18

e

−

−

−

−

−

−15

−

−15

−15

Signal and DIO (BR=3 × 10-15)

Counts per 0.1 MeV/c

0.18
0.16

−

0.14
0.12

e

0.1

15

−14

15

−14

0.08
0.06
0.04
0.02

0
101.5

102

102.5

103

103.5

104

104.5

105
105.5
106
Momentum [MeV/c]−14

twice because of the use of caseonly ofdownstream
hemisphereseenthedescribe
muon-stoppingno candidate
observation.
Asfromwe willlater, backgroundtarget. Trigger and analysis eﬃciencies have not been estimated in a reliable manner withthese setup, thus we
1 suppose conservatively 10% in total in either case. The single event
B(µ− + Al → e−sensitivity+ Al) ∼ can be calculated, from these assumption;
Nµ · fcap ·Figure
Ae 106: Left: Distributions of the reconstructed µ− N → e− N conversi
events. The verticalscale is normalized so that the integrated area of the sig−14• 1/(2 × 1015 × 0.71branching× 0.1) = ratio
0.7 ×of
10B(µN→ eN ) = 3.1 × 10−15 . Right: The integrated fractio
for the cylindricalsignals
shape anddetector
option,and
17a function of the low side of the integration range a
DIO events-15
as
range
is
106
MeV/c.
The
momentum window for signals is selected to be f
• 1/(2 × 1015 × 0.32 × 0.1) = 1.6 × 10−14that the DIO contamination
would be 0.01 events.
17-15
for the transverse tracker detector option.

SignalSensitivity
B(µ+ Al ⇥ e

Akira SATO

+ Al) = 3.3
3.1

15
10 17

142
17
• fcap = 0.6
15
B(µ
+
Al
⇥
e
+
Al)
=
3.3 (90%C.L.)
10
3.1
B(µ
+
Al
⇥
e
+
Al)
<
7
10
6
• Ae = 0.043
B(µ + Al ⇥ e + Al) < 7 10
(90%C.L.)• Nμ = 1.23x1016 muons
MuSIC
andofCOMET
μ-e 3.7
conversion
searches in 54
These correspond to 90% C.L. upper
limits
1.6 × 10 for and× 10
respectively
−14

−14

107
Background Estimation for
COMET
Phase-Ivertical scale is normalized so that the integrated area of the sign
COMET
Phase-I : the
Backgrounds
8.4: Summary of estimated background events for a single-event sensitivity of

TER 8. SIGNAL SENSITIVITY AND BACKGROUNDS−15

10
with a proton extinction factor of 3 × 10
rtional to the proton extinction factor.

−11

event, assuming a branching ratio of B(µN → eN ) = 3 × 10−15 . A. The numbers with ∗ is directlyof the estimation of contamination from DIO electrons is presented i
this study, the momentum cut of 104.1 MeV/c < Pe < 106 MeV/c, whmomentum,is determined in such a way that a contamination from D
estimated events
events 0.01
is expected for a single event sensitivity of µ− −e− conversion

Background
Muon decay in orbit
Radiative muon capture
Neutron emission after muon capture
Charged particle emission after muon capture
Radiative pion capture
Beam electrons
Muon decay in flight
Pion decay in flight
Neutron induced background
Delayed radiative pion capture
Anti-proton induced backgrounds
Electrons from cosmic ray muons
Total< 0.001< 0.001< 0.001
0.0096∗< 0.00048∗

DIO

signal

∼ 0∗
0.002
0.007
< 0.0002
0.03

Summary of background estimations
Figure 8.2: -11
Distributions of reconstructed µ− −e− conversion signa

with proton extinction factor of 3x10

DIO
eventsThe backgroundvertical scale is normalized so that the integrated
8.4 shows a summary of the estimated backgrounds. The
total
estimated−15
to oneevent extinction
with its branching ratio of B(µN → eN ) = 3 × 10
ut 0.03 events for a single event sensitivity of 3.1 × 10equalwitha protoncut of
MeV/c< Pe < 106 MeV/c, where Pe is an electron momof 3 × 10−11 . If the proton extinction factor is improved,
the104.1
expectedbackground-15
are further reduced.

Expected BG events are about 0.03 at S.E.S. of 3x10 .

Akira SATO

The eﬃciencies of the timing selection and the trigger and DAQ asame as those in the COMET CDR [78]. From these, the net accept
conversion signal, Aµ-e = 0.062, is obtained. The breakdown of the ac
MuSIC and COMET for μ-e conversion searches

55

COMET Collaboration-collaboration
ase-I
COMET : Collaboration

Y. E. Cheung , B. Chiladze , D. Clarke , M. Danil
W. Da Silva20 , C. Densham30 , G. Devidze32 , P. Dorna
A. Edmonds35 , L. Epshteyn6, 27 , P. Evtoukhovich
University College London, UK
M. Koike, J. Sato
M. Finger Jr7 , Y. Fujii2 , Y. Fukao15 , J-F. Gena
E. Hungerford
Saitama
University, Japan
Mihara, T. Nakamoto, H. Nishiguchi, T. Ogitsu, C. Omori, N. Saito, K. Sasaki,
D. Grigoriev6, 27, 28 , K. Gritsay14 , R. Han1 , K. Haseg
Yu. Bagaturia
2
UniversityD.ofBryman
Houston, USA
M. Sugano,Y.
Takubo,M.
Tanaka,M.
Tomizawa,
T.
Uchida,A.
Yamamoto,
3
3
Ilia State University (ISU), Tbilisi, Georgia
M. I. Hossain16 , Z. A. Ibrahim21 , Y. Igarashi15 , F
M. Yamanaka, M. Yoshida, Y. Yoshii, K. Yoshimura
University of British Columbia, Vancouver, Canada
W.A. Tajuddin
K. Ishibashi19 , S. Ishimoto15 , T. Itahashi29 , S. Ito29 , T
n,P. Dauncey, P. Dornan, B. Krikler, A. Kurup, J. Nash, J. Pasternak, Y. UchidaHigh Energy Accelerator Research
Organization(KEK),Japan
Tsukuba, Japan
4
S. Cook, R.
D’Arcy, A. of
Edmonds,
M.Malaysia
Lancaster, M. Wing
Osaka
University,
Osaka,
University
Malaya,P. Jonsson11 , V. Kalinnikov14 , F. Kapusta20 , H. Kataya
Imperial
CollegeLondon, UK
University College London, UK
The
COMET
Collaboration
Yu. Bagaturia
B. Khazin§6, 28 , A. Khvedelidze14 , M. Koike36 , G. A.
M.
Koike, J. Sato
R.B. Appleby, W. Bertsche, M. Gersabeck, H. Owen, C. Parkes
P.
Sarin, S.Research
Umasankar
KyotoUniversity
University
Reactor Institute,
Kyoto, Japan
J.F. Solehan, W.A. Tajuddin
Ilia State(ISU),
Tbilisi,Georgia
E. Kulish14 , Y. Kuno29 , Y. Kuriyama18 , Y. Kurochzanin,
Saitama
University,
Japan
Universityof Manchester, UK
Indian Institute of Technology Bonbay, India8, 22 , Y. Arimoto
15 , 2
University of Malaya, Malaysia
35 , H. B.
R. Akhmetshin6, 28 , V. Anishchik4 , M. Aoki29 , R. B. Appleby
C.V. Tao
M. Lancaster
Li , W. G. Li2 , A. Liparteliani
P. Dauncey, P. Dornan, B. Krikler, A. Kurup,
J. Nash, J. Pasternak, Y. Uchida
30 , S. Chen
25 ,D.
BrymanY.Science,
Iwashita
College of Natural
National
Vietnam University, Vietnam
Azfar H. Owen, C. Parkes, G. Xia
14
R.B. Appleby, W. Bertsche, M.F.Gersabeck,
Y. Bagaturia33 , Y. Ban3 , W. Bertsche22 , A. Bondar6, 28 , S. G.
CanferMacharashvili,
Y.
Makida15 , Y. Mao3 , O. Ma
Imperial
CollegeLondon,UK Vancouver,ara,
25 , B. Chiladze32 , D. Clarke30 , M. Danilov13, 23 , P. D. Dauncey1115
20 ,Institute for Chemical
Research,
Kyoto
University,
Kyoto, Japan
UniversityofBritishColumbia,
CanadaUniversity of ofManchester,
UK
University
Oxford, UK∗
Y.
E.
Cheung
,
J.
David
,
M.
Aoki,
I.H.
Hasim
T.
Hayashi,
Y.
Hino,
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The COMETCollaboration
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Y. Mori , N. Mosulishvili32 , E. Motuk35 , Y. Nakai
Md.
Imam
Hossain(Sep.
2014)
University,
Osaka, Vietnam
Japan
35 , L. Epshteyn6, 27 , P. Evtoukhovich14 , G. Fedotovich6, 28
7,University of Oxford, UK
IndianofOsaka
Technology
Bonbay,India
Institute
forInstitute
NuclearUniversity
ScienceandCollege
Technology,
11,, M.
15 , T. Numao34
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FingerLondon,
UK
University Technology Malaysia
Nash, H. Nishiguchi
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Hungerford
Saitama
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asaki,
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High Energy
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20 , H. Katayama29 , K.14
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Institute for Theoretical and Experimental
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acharashvili, A. Moiseenko,
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Warren
,
M.
Wing
,
14
15
3
13
29
15
. Xia
G. Macharashvili , Y. Makida , Y. Mao , O. Markin , Y. Matsumoto , 29T. Mibe 2,,25
8 The Cockcroft
28 , V. Rusinov
13, 23 , A.15 ,Ryzhenenkov
6,
14 ,22 , H.6, Yamaguchi
19 , A. Yamamoto
2428
Daresbury
Labo, Tbilisi,
T. S.
, C. Wu14 , 4 ,, G.
M. Yamanaka, , B.Institute,V.
Ponariadov
A. XiaPopov
Sabirov
21 , Wong
S. Mihara15 , F. Mohamad Idris21 , K. A. Mohamed Kamal Azmi
A.
Moiseenko
9 Czech
19
29
15
15
19
2
6,
28
Technical
University,
Prag
15
29
10
15
29
31
6,
28 ,
Y.
Yang
,
H.
Yoshida,M.
Yoshida,Y.
Yoshii,T.
Yoshioka
,
Y.
Yuan
,
Y.
Yudin
,
18
32
35
19
15
29
N.
Saito
,
H.
Sakamoto
,
P.
Sarin
,
K.
Sasaki
,
A.
Sato
,
J.
Sato
,
D.
ShemyakinY. Mori , N. Mosulishvili , E. Motuk , Y. Nakai , T. Nakamoto , Y.
Nakazawa,
10 Indian Institute of Technology
2
192
Zhang
,
N.,15Y.
ShigyoShoukavy5 , M. Slunecka7 , M. Sugano15 , Y. Takubo15 ,11M. Tanaka15 ,J. Nash11 , M. Nioradze32 , H. Nishiguchi15 , T. Numao34 , J. O’Dell30 ,J.T.Zhang
Ogitsu, K.
Oishi,19D.
,
Imperial College
1219 , London,any
Velicheva
K. Okamoto29 , C. Omori15 , T. Ota31 , H. Owen22 , C. Parkes22 , J. Pasternak11, Tarkovsky13, 23 , Y. Tevzadze32 , N. D. Thong2912
C., C.V.Plostinar
Tao26 ,30E.
, Institute
V. Thuan, J. Tojo
for
NuclearScienceand Tech
1 North China 9Electric
15 , N. H.Beijing,
32 , N. M.
29 , Z. Tsamalaidze14 ,Power University,of Truong
China
V. Ponariadov4 , A. Popov6, 28 , V. Rusinov13, 23 , A. Ryzhenenkov6, 28M.
, B.
Sabirov14, ,M. Tomizawa
13 InstituteTomasek
Tran29People’s, I. TrekRepublic
for Theoretical and Experiment
2 Institute of High
15
29
10
15
29
31
6,
28
14,, Energy
22 , (IHEP),
15 , People’s
11 , K.
15 , S. Umasankar10 ,Physics
Beijing,
Republicof China
N. Saito , H. Sakamoto , P. Sarin , K. Sasaki , A. Sato , J. Sato , D.
14 Joint
N.Shemyakin
Tsverava
S. TygierT. UchidaY. Uchida
Ueno
Institute for Nuclear Research
3 Peking
15 , University, Beijing, People’s Republic of China
N. Shigyo19 , D. Shoukavy5 , M. Slunecka7 , M. Sugano15 , Y. Takubo15 , M. Tanaka
15 High1414
9
21
35 , M. Wing
35 , Organiza
EnergyAccelerator
Research
E. Velicheva, A. Volkov , V. Vrba , W. A. T. Wan Abdullah , M. Warren
4 Belarusian
26
13,
23
32
29
12
19
State
Minsk, Belarus
C. V. Tao , E. Tarkovsky, Y. Tevzadze , N. D. Thong , V. Thuan , J. Tojo29 ,16 King Abdulaziz
2, 25 , University
22 ,(BSU),
19 , A. Yamamoto15 , M.
24University,
T.
S.
Wong
,
C.
Wu
G.
Xia
H.
Yamaguchi
Yamanaka,
5 B.I.29Stepanov Institute14ofNational Academy of Sciences of Belarus, Minsk,
Belarus2
M. Tomasek9 , M. Tomizawa15 , N. H. Tran29 , I. Trek32 , N. M. Truong, Z. Tsamalaidze, Physics,
19 , H.
29 , M. Yoshida15 , Y. Yoshii15 , T. Yoshioka17
19Institute6, 28 ,
for ,Chemical
Research,
Kyoto
rmany
o,
6 Budker
14
22
15
11
15
10
Y.
Yang
Yoshida
,
Y.
Yuan
Y.
Yudin
of Nuclear Physics (BINP), Novosibirsk, Russia
N. Tsverava , S. Tygier , T. Uchida , Y. Uchida , K. Ueno , S. UmasankarInstitute,18 Research Reactor Institute, Kyoto Unng
2 , Y.
2
7 Charles
14
14
9
21
35
35
J.
Zhang
Zhang
University, Prague, Czech Republic
E. Velicheva , A. Volkov , V. Vrba , W. A. T. Wan Abdullah , M. Warren , M. Wing ,19 Kyushu University, Fuku
8 The Cockcroft
24 ,Institute, Daresbury Laboratory, Warrington,
UKT. S. Wong29 , C. Wu2, 25 , G. Xia22 , H. Yamaguchi19 , A. Yamamoto15 , M. Yamanaka
20 LaboratoryofNuclearandHigh
Energy Physics (LPNH
96,
28 ,
Czech
Technical University, Prague, Czech Republic
Y. Yang19 , H. Yoshida29 , M. Yoshida15 , Y. Yoshii15 , T. Yoshioka19 , Y. Yuan2 , Y. Yudin
1 NorthandMarie Curie (UPMC), P
China
Electric
Power
University,
Beijing,
People’sRepublicof
China
10 Indian22Institute of Technology, Bombay, India 21
J. Zhang , Y. Zhang
2 Institute of High Energy Physics (IHEP), Beijing,
National
for Particle
Physics, Universiti
People’sCentre
Republicof China
11 Imperial College London, London, UK
12 Institute for 3Nuclear
Peking Science
University,
Beijing, People’s
Republic of China
and Technology,
Hanoi, Vietnam
1 North China Electric Power University, Beijing, People’s Republic of China
4 Belarusian State University (BSU), Minsk, Belarus
13 Institute for Theoreticaland Experimental Physics (ITEP), Russia
2 Institute of High Energy Physics (IHEP), Beijing, People’s Republic of China
14 Joint Institute for Nuclear Research (JINR), Dubna, Russia
53 Peking University, Beijing, People’s Republic of China B.I. Stepanov
Institute of Physics, National Academy of Sciences of Belarus, Minsk, Belarus
15 High Energy
6 Budker
Accelerator
Research(KEK),
Tsukuba,Japan
4 Belarusian State University (BSU), Minsk, Belarus
Instituteof Organization
Nuclear Physics(BINP),
Novosibirsk,
Russia16
University,
Saudi
Arabia Czech Republic
7 Charles
5 B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Minsk, Belarus King Abdulaziz
University,
Prague,17
6 Budker Institute of Nuclear Physics (BINP), Novosibirsk, Russia Institute8 for Chemical Research, Kyoto University, Kyoto, JapanThe Cockcroft Institute, Daresbury Laboratory, Warrington, UK
18 Research
ReactorInstitute, Kyoto University, Kyoto, Japan
7 Charles University, Prague, Czech Republic
9 CzechTechnical Fukuoka,
University,
Prague, Czech Republic
19 Kyushu
University,
Japan
8 The Cockcroft Institute, Daresbury Laboratory, Warrington, UK
10 Indian Institute of Technology, Bombay, India
20 Laboratory of Nuclear and High Energy
Physics(LPNHE),
CNRS-IN2P3
and University Pierre
9 Czech Technical University, Prague, Czech Republic
11 Imperial College London, London, UK
and Marie Curie(UPMC), Paris, France
10 Indian Institute of Technology, Bombay, India
12 Institute21 National Centre forParticle Physics,
Universiti
Malaya,Lumpur,Hanoi,
Malaysia
for Nuclear
Scienceand KualaTechnology,
Vietnam
11 Imperial College London, London, UK

T. Nakamoto, H. Nishiguchi, T. Ogitsu,
C. Omori, N. Saito, K. Sasaki, M. Sugano,
R. Palmer
Y. Takubo,
M. Tanaka,
M. Tomizawa,T. Uchida,
A. Yamamoto,
M. Yamanaka,
Departmentof Physics,
Brookhaven
National
Laboratory,USA
M. Yoshida, Y. Yoshii, K. YoshimuraHigh K.
EnergyAccelerator
Research M.
Organization
Tsukuba,
Japan T. Mibe,
Arimoto,Hasegawa,
Y. Igarashi,
Ikeno, S. (KEK),
Ishimoto,
Y. Makida,

M. Aoki, I.H. Hasim T. Hayashi, Y. Hino, T. Iwami, T. Itahashi, S. Ito, Y. Kuno∗ ,Y. Matsumoto, T.H. Nam, H. Sakamoto, A. Sato, N.D. Thong, N.M. Truong, K. Yai
S. Cook, R. D’Arcy, A. Edmonds, M. Lancaster, M. Wing
Osaka University, Osaka, Japan

g...

COMET
Collaboration
164
collaborators,
37 institutes
ration• 107 collaborators
New members
areinstitutes
117 collaborators
25•
LPNHE, France
27 institutes
collaborators
University, Japan
12 countries• 107 Kyushu• 11 countries
New members
areinstitutes
117 collaborators
25•
LPNHE, France
27 institutes
107 Kyushu
collaborators
University, Japan
12 countries• 11 countries
164 collaborators
37 institutes, 13 countries

164 collaborators
37 institutes, 12 countries
S.Mihara, J-PARC PAC Meeting, 16/Mar/2012

164 collaborators
37 institutes, 12 countries
a, J-PARC PAC Meeting, 16/Mar/2012

areinstitutes
117 collaborators
25

ce
Japan

Me

27 institutes
12 countries

11 countries

ar/2012

12 Institute for Nuclear Science and Technology, Hanoi, Vietnam

13 Institute for Theoretical and Experimental Physics (ITEP), Russia

13 Institute for Theoretical and Experimental Physics (ITEP), Russia

14 Joint Institute for Nuclear Research (JINR), Dubna, Russia

14 Joint Institute for Nuclear Research (JINR), Dubna, Russia

15 High Energy Accelerator Research Organization (KEK), Tsukuba, Japan

15 High Energy Accelerator Research Organization (KEK), Tsukuba, Japan
16 King Abdulaziz University, Saudi Arabia
17 Institute for Chemical Research, Kyoto University, Kyoto, Japan
18 Research Reactor Institute, Kyoto University, Kyoto, Japan
19 Kyushu University, Fukuoka, Japan

16 King Abdulaziz University, Saudi Arabia
17 Institute for Chemical Research, Kyoto University, Kyoto, Japan
18 Research Reactor Institute, Kyoto University, Kyoto, Japan
19 Kyushu University, Fukuoka, Japan

20 Laboratory of Nuclear and High Energy Physics (LPNHE), CNRS-IN2P3 and University Pierre

20 Laboratory of Nuclear and High Energy Physics (LPNHE), CNRS-IN2P3 and University Pierre

and Marie Curie (UPMC), Paris, France
COMET Collaboration meeting@KEK
26-30
National Centre for Particle Physics, Universiti Malaya, Kuala Lumpur, Malaysia
National
Centre forJan
Particle 2015
Physics, Universiti Malaya, Kuala Lumpur,21Malaysia

and Marie Curie (UPMC), Paris, France

21

Akira SATO

MuSIC and COMET for μ-e conversionMuSIC
searches56ationCOMET Status: Experimental HallCOMET Building Completed !

COMET building completed!

FX&
SX&

ansport Solenoid at J-PARC
Tokai&Campus

Transport solenoid was installed.
Akira SATO

MuSIC and COMET for μ-e conversion searches

57

COMET : Proton Beamline

Akira SATO

MuSIC and COMET for μ-e conversionMuSIC
searches58

・Assemble the end plate and support rin
CDCConstruction
Current
andadhesion
with
epoxy
bond
(same onemble
COMET Status: CDC
・Measurement of Cosmic-ray
the level oftheendplattest@KEK
テキスト
assemble, and the accuracy is within the
OMETCyDet Endplate
CDC Assemble

OMET

4

one of the endplates

is done in factory of 東邦工業

W

duced our end plates

CyDet Outer wall

CFRP outer wall + support ring

Akira SATO

CyDet on wire
stringing assembly
one of the endplates

CyDet assembly・Assemble is done in factory of 東邦工業
MuSIC and COMET for μ-e conversion searches
which produced our end plates

59

StrECAL Beam Test
atTohoku Status:
University(Photos)
COMET
Straw
Tracker

ୈ8ষ

102

102

Beam tests@Tohoku U.

Eୈ 8 ষ ECAL ࢼ࡞‫ػ‬ͷվྑ਺ͷ૿ՃΛট͕͘ɺLED ͷ‫ۦ‬ಈʹ໰୊͕ੜͨ͡৔߹Ͱ΋ɺӨ‫ڹ‬Λड͚Δν
ϯωϧͷΈͰࡁΉͱ͍͏ར఺͕͋Δɻ਺ͷ૿ՃΛট͕͘ɺLED ͷ‫ۦ‬ಈʹ໰୊͕ੜͨ͡৔߹Ͱ΋ɺӨ‫ڹ‬Λड͚Δνϟϯωϧ͕ 4 νϟ
取り付け図
図LED Λ‫ۦ‬ಈͤ͞Δࠩಈ৴߸Λ࣮‫͢ݱ‬ΔͨΊʹɺύϫʔτϥϯδελΛ࢖ϯωϧͷΈͰࡁΉͱ͍͏ར఺͕͋Δɻ

First StrECAL-Combined
Beam
Downst.
BDC Test -ECAL Feed throughLED Λ‫ۦ‬ಈͤ͞Δࠩಈ৴߸Λ࣮‫͢ݱ‬ΔͨΊʹɺύϫʔτϥϯδελΛ࢖༻͍͕ͯͨ͠ɺ֤
ૉࢠͷ‫ݸ‬ମ͔ࠩΒ̎‫ۃ‬ͷλΠϛϯάΛଗ͑Δࣄ͸೉͔ͬͨ͠ɻͦ͜Ͱɺࠩಈ

SiPMs
ૉࢠͷ‫ݸ‬ମ͔ࠩΒ̎‫ۃ‬ͷλΠϛϯάΛଗ͑Δࣄ͸೉͔ͬͨ͠ɻͦ͜ͰɺࠩಈΞϯϓΛ༻͍ΔΑ
͏มߋͨ͠ɻҎલʹࠩಈΞϯϓΛ࢖༻͢ΔҊ΋͕͋ͬͨɺ64 νϟϯωϧ෼

Tracker
Beam defining counter in vacuum͏มߋͨ͠ɻҎલʹࠩಈΞϯϓΛ࢖༻͢ΔҊ΋͕͋ͬͨɺ64 νϟϯωϧ෼ͷిྲྀ͸‫͖Ͱڅڙ‬ͳ͍ͱͯ͠ഇҊͱͳ͍ͬͯͨɻલड़ͷ௨Γɺѻ͏ LED ਺Λ 4 ͭʹมߋ͠ͳ͍ͱͯ͠ഇҊͱͳ͍ͬͯͨɻલड़ͷ௨Γɺѻ͏ LED ਺Λ 4 ͭʹมߋͨ͠ࣄͰɺLED υϥΠόʹର͢Δిྲྀ‫څڙ‬ೳྗͷཁ‫͕ٻ‬؇࿨͞ΕɺࠩಈΞϯϓΛ࢖༻͢Δӡͼͱ
ECALΠόʹର͢Δిྲྀ‫څڙ‬ೳྗͷཁ‫͕ٻ‬؇࿨͞ΕɺࠩಈΞϯϓΛ࢖༻͢ΔӡͼͱͳͬͨɻSiPMs

Developed by K. Noguchi and T. Saito.
Beam
Beam

✦

✦

★

✦

8.2

1 mm2 square fiber used.

ϏʔϜࢼ‫ݧ‬8.2

PMTϏʔϜࢼ‫ݧ‬2017 ೥102
3 ݄ʹɺࠓճͷϏʔϜࢼ‫ͱݧ‬ಉ͡౦๺େֶిࢠޫཧֶ‫ڀݚ‬ηϯλʔʹͯɺϏʔϜࢼ
2017 ೥ 3 ݄ʹɺࠓճͷϏʔϜࢼ‫ͱݧ‬ಉ͡౦๺େֶిࢠޫཧֶ‫ڀݚ‬ηϯλ

32x32 mm2 (upst.) and 64x64 mm2 (downst.)

Peamps‫ݧ‬Λ༧ఆ͍ͯ͠Δɻ͜͜Ͱલड़ͷվྑΛՃ͑ͨ
ECAL ࢼ࡞‫ػ‬ͷੑೳධՁΛߦ͏ɻ·ͨɺετ‫ݧ‬Λ༧ఆ͍ͯ͠Δɻ͜͜Ͱલड़ͷվྑΛՃ͑ͨ
ECAL ࢼ࡞‫ػ‬ͷੑೳධՁΛ

Upst. BDC
An end of each readout by SiPM (MPPC).

ϩʔνϡʔϒඈ੻‫ݕ‬ग़‫ͱث‬૊Έ߹Θͤͨࢼ‫ݧ‬΋ߦ͏ɻ‫ܭࡏݱ‬ը͍ͯ͠ΔϏʔϜࢼ‫ݧ‬ͷηοτϩʔνϡʔϒඈ੻‫ݕ‬ग़‫ͱث‬૊Έ߹Θͤͨࢼ‫ݧ‬΋ߦ͏ɻ‫ܭࡏݱ‬ը͍ͯ͠ΔϏ਺ͷ૿ՃΛট͕͘ɺ
LED ͷ‫ۦ‬ಈʹ໰୊͕ੜͨ͡৔߹Ͱ΋ɺӨ‫ڹ‬PMTΞοϓͷ໛ࣜਤΛਤ 8.3 ʹࣔ͢ɻ̎୆ͷ BDCɺετϩʔνϡʔϒඈ੻‫ݕ‬ग़‫ث‬ɺ
ECAL Λɺશ

4
2016/10/14
Ξοϓͷ໛ࣜਤΛਤ
8.3 ʹࣔ͢ɻ̎୆ͷBDCɺετϩʔνϡʔϒඈ੻‫ݕ‬ग़

COMET-Q meetingͯಉҰͷਅۭϘϦϡʔϜ಺ʹઃஔ͠ϏʔϜࢼ‫ݧ‬Λߦ͏ɻ͜ͷ
BDC ͸ɺਅۭதͰͷಈ࡞ʹରԠϯωϧͷΈͰࡁΉͱ͍͏ར఺͕͋Δɻ

ECAL-Combined Beam Test The other end of all the fibers readout by PMT.
Tracker★

ͯಉҰͷਅۭϘϦϡʔϜ಺ʹઃஔ͠ϏʔϜࢼ‫ݧ‬Λߦ͏ɻ͜ͷ BDC ͸ɺਅۭͨ͠όʔδϣϯͰ͋Γɺ‫ࡏݱ‬։ൃதͰ͋Δɻ
Cross section of BDC

2016/10/14
LED Λ‫ۦ‬ಈͤ͞Δࠩಈ৴߸Λ࣮‫͢ݱ‬ΔͨΊʹɺύϫʔτϥϯ

COMET-Q meeting3ͨ͠όʔδϣϯͰ͋Γɺ‫ࡏݱ‬։ൃதͰ͋Δɻ

Used as the trigger.

ૉࢠͷ‫ݸ‬ମ͔ࠩΒ̎‫ۃ‬ͷλΠϛϯάΛଗ͑Δࣄ͸೉͔ͬͨ͠ɻͦ

•Vacuumrackerprototype< 1Pa
achieved in
eam test
in 2015&2016.
entire the volume.
y-chained ROESTIs.

Upst. BDC Hit Positions (ar50et50_1950v)

Y (mm)✦

15

Vacuum Pumping of Straw Tracker& ECAL1000Πόʹର͢Δిྲྀ‫څڙ‬ೳྗͷཁ‫͕ٻ‬؇࿨͞ΕɺࠩಈΞϯϓΛ࢖༻
800

10

105

10

1000

0

600

−400
10
200

400
8.2
200

800

104

600

−5

−10

Yamaguchi.
Assembled BDC

206ͳ͍ͱͯ͠ഇҊͱͳ͍ͬͯͨɻલड़ͷ௨Γɺѻ͏ LED ਺Λ 4 ͭ

1200

0

−15
−15 −10 −5

1200

30

1400

10
5

type

0

5

10 15
X (mm)

103

−20

102

−30
−30 −20 −10
10

Akira SATO

032x32 mm21 (upst.) and
Hit map of the BDCs.
64x64
mm2
(downst.)10−1experience in the last experiment.4-CM22 / 30th May. 2017͏มߋͨ͠ɻҎલʹࠩಈΞϯϓΛ࢖༻͢ΔҊ΋͕͋ͬͨɺ64 ν

Dowst. BDC Hit Positions (ar50et50_1900v)

Vacuum Pressure (Pa)Y (mm)

✦

ー

10

ϏʔϜࢼ‫ݧ‬02017
೥ 3 ݄ʹɺࠓճͷϏʔϜࢼ‫ͱݧ‬ಉ͡౦๺େֶిࢠޫཧֶ

10 20 30
X (mm)‫ݧ‬Λ༧ఆ͍ͯ͠Δɻ͜͜Ͱલड़ͷվྑΛՃ͑ͨ ECAL ࢼ࡞‫ػ‬ͷ

ਤ 8.3:
೥ 3 ݄ʹ‫ܭ‬ըதͷϏʔϜࢼ‫ݧ‬ͷηοτΞοϓͷ໛ࣜਤɻ༗‫ײ‬෺࣭Ͱ͋Δ
BDC ͷ
10201710ϩʔνϡʔϒඈ੻‫ݕ‬ग़‫ͱث‬૊Έ߹Θͤͨࢼ‫ݧ‬΋ߦ͏ɻ‫ܭࡏݱ‬ը
2

3

Full scale Straw tracker prototyp

Pumping Time (min.)Kou Oishi / Kyushu UniversityϓϥενοΫγϯνϨʔγϣϯϑΝΠόʔɺετϩʔνϡʔϒඈ੻‫ݕ‬ग़‫ث‬ͷετϩʔνϡʔ

ルー基板

Figure11.33: Full-scale prototype;(Left) Partially completed
without vacuum w
Ξοϓͷ໛ࣜਤΛਤ
8.3 ʹࣔ͢ɻ̎୆ͷBDCɺετϩʔνϡʔ
andCOMET for μ-e conversion searches 60
view of the completed MuSIC
full-scale
prototypeϒɺECAL ͷ LYSO ݁থΛਫ৭Ͱද‫ͨ͠ه‬ɻ

まとめ
大阪大学で大強度ミューオン源MuSICの開発に成功し、従来より1000倍以上効率よくミューオンを生成することができるようになった。
阪大核物理研究センターに日本初のDCミューオン施設が稼働し、~106µ/秒の強度のミューオンが利用できる。
物性物理、原子核物理、
非破壊元素分析、核変換、核融合基礎研究
J-PARCではMuSICを応用して、1010µ/秒の負ミューオン生成。µ-e転換を探索するCOMET実験の準備が進んでいる。
2020年頃から物理Runなのでお楽しみに。
COMET実験の後に何をすべきか？
Akira SATO

MuSIC and COMET for μ-e conversion searches

61