August 7th, 2015@福井・あいあいプラザ
第12回日本加速器学会年会

J-PARC/MUSEにおけるミュオン回転標的の現状
50 GeV Synchrotron(0.75 MW)3 GeV Synchrotron(25 Hz, 1MW)

Tsukuba(KEK)
Toukai(J-PARC)

Tokyo

Linac
(181MeV  400 MeV)

Materials and Life Science
Experimental Facility（Muon & Neutron)

J-PARC Center, MLF Division, Muon Section (KEK-IMSS)
Shunsuke Makimura (shunsuke.makimura@kek.jp)

J-PARC/MLF/MUSE & MUON TARGET
MUon Science Establishment (MUSE)

NeutronTarget3GeV-RCS
1MW in future
500kW at present

Muon Target

Materials and Life Science Experimental Facility (MLF)

The most intense pulsed muon beam all over the world

PSI; 1MW
Rotating Target
LINAC Upgrade

New RCSschedule(undecided)

We are here

MR New PS

ISIS/RAL; 200kW
Fixed Target

Earthquake

HadronAcc.

Country

Japan

U.K.

Facility

J-PARC MUSE

RAL ISIS

3Switzerland
PSI

P Intensity [MW]1.0(Goal)
0.16
1.3
2014年9月に固定標的方式から回転標的方式
Surface Mu+ [/s] 6 x 10 (U)@0.2MW
6 x 103 x 10に交換を行った。
7DC / Pulse

Pulse (25Hz)

5Pulse (50Hz)

7DCMuon Fixed Target (Graphite)
Isotropic Graphite
IG-430U (Toyo Tanso)Diameter; 70mm
Thickness; 20mm

P-Beam diameter; 16 mm (2σ)
4kW heat @ 1MW proton beam

70 mm

20 mm

Stainless steel pipe (Water)
Copper frame
Hot Iso-static Press method

Stable proton beam operation
without replacements for 5 years(ISIS/RAL; Beam Power 200kW,
3 ladder-targets ~Lifetime; 1 year )Lifetime & Replacement of Muon Target Radiation damage of graphite; Dimensional change
Lifetime; < 1year @1MW beam operation
 Replacement by remote handling

1dpa

Journal of Nuclear Materials 195(1992)44-50.
graphite1991 [No.150] 290-302

Max. Mises stress; 30MPaStrength; 39 MPa

Evaluation for July, 2014

Beam spot will shrink by proton irradiation.

Rotating Target
Learning from Paul Scherrer Institute,
Rotating target method is applied todistribute the irradiation damage ofgraphite to a wider area.

Proton beam

Current fixed target

Rotating target

The lifetime of graphite becomeslong enough.
The lifetime of bearings is critical.
Solid lubricant; Silver coating with MoS2 at PSI
 Disulfide tungsten at MUSE
Expected lifetime; 10 years

E target at Paul Scherrer Institute (PSI)
Lifetime; less than 1 year

April, 2013

Collaboration with PSI Target group since 2004

Bearing & Solid lubricants
For our target, the bearing is used under 100 MGy/year, 400 Kelvins, 10-5 Pa
TypeTemp.
(Kelvins)

Pressure(Pa)Radiation

Speed(rpm)

Storage

Lifetime@15rpm(hour)

MoS2

coating<570

105 to 10-5

general

<500

air

1100

Ag

coating<600

10-3 to 10-10

general<500

vacuum5800

WS2

Separator<600

105 to 10-5few

<210

air

110000Retainer, balls, &rings, coated by
MoS2 or Silver

Separator madeof sinteredcompact ofWS2

Great amount of Lubricant

Captured fromJTEKT(KOYO) CatalogEvaluation by the formulaof the JTEKT Catalog

Disulfide Tungsten is used for MUSE target.
Anticipated Lifetime is 20 years!!
Radiation resistance of WS2 should be confirmed.

Radiation Resistance of WS2

Electron beam irradiation
JAEA, Takasaki,2MV, 1mA, 20hours, 100MGy
Durability tests with load & heat
4.5 million revolutions,
1year@ beam line
No irradiation effect was observed.

Mock-up ofRotating Target

330 mmDurability tests ofTarget & bearings
Heating & Rotating tests

Protonbeam

Heating test

Motor torque (x 10 %)Operation for 4 days

9 days with 300 r.p.m.
(4800h @15 r.p.m.)

Operation for 5 days

It will work at least for 1 year!!

30th July, 2014

Replacement of the used Fixed target
M2 lineM1 lineRadiation dose;
750μSv/h @12 m(150mSv/h@30cm）

To neutron
sourceRemote-controlled camera

No crack was observed.
400 mSv/h @20cm
Dose-meter & Digital camera
10cm
gap

7th July, 2014

FL4m

Transportation totentative storage
vesselInstallation of Rotating Target
Rotating Target was successfully installed on
16th September of 2014.

 Vacuum pressure; 10-5 Pa Control system; Confirmed

Cooling
JacketOperation of muon rotating target
300-kW & 400-kW operation for 3 months
600-kW operations for 1 hour on 8th Apr./2015
500-kW operation for 1 week
Motor torque has been remaining constant.

Horizontal
shaft

Bearing

Protonbeam

Thermocouples for
shaft temp.

試験運用中

Graphite
wheel

Graphite temperature by thermal radiation
300kW

500kW

1MW

Shaft (Simulation)

71 degC

84 degC

112 degC

Shaft (Measurement)

78 degC

95 degC-

Graphite (Simulation)

400 degC

475 degC

620 degC

Th. radiation (Measurement)

45 degC

60 degC-Summary Since 2008, Stable beam operation by Graphite Fixed target.
 Graphite Rotating Target was installed last September.
 Stable proton beam operation by Graphite Rotating target

ACKNOWLEDGMENT
 回転標的加熱回転試験機；日立造船
 回転標的実機；入江工研
 軸受；JTEKT
 潤滑材の電子線照射試験；大島氏、花屋氏（原研高崎）

Thank you for your attention