P R E S E N T S T A T U S O F M U O N P R O D U C T I O N T A R G E T

A T J - P A R C M L F M U S E

J - PA R C C E N T E R , M L F D I V I S I O N , M U O N S E C T I O N

H I G H E N E R G Y A C C E L E R ATO R R E S E A R C H O R G A N I Z AT I O N , I N S T I T U T E O F M AT E R I A L A N D S T R U C T U R A L S C I E N C E

( I M S S , K E K )

S H U N S U K E M A K I M U R A , S . M ATO B A , N . K AWA M U R A

O N B E H A L F O F M U O N S C I E N C E S E C T I O N

S H U N S U K E . M A K I M U R A @ K E K . J P1

J - PA R C S Y M P O S I U M 2 0 1 9 @ E P O C A L T S U K U B A

2 6 T H S E P T E M B E R , 2 0 1 9

PRIVATE AFFAIR

2

This talk is my final presentation and my final job for muon production target.

My next interest is to develop the target out of SiC and tungsten. In four days, I will transfer to Hadron Section in J-PARC to construct COMET target.

CONTENTS1. Overview of Muon Production Target at J-PARC

MLF MUSE

2. Muon Target System

3. Muon Production Target

4. Recent Progress of Muon Production Target

5. Acknowledgement & Summary

3

O V E R V I E W O F M U O N P R O D U C T I O N T A R G E T A T J - P A R C M L F M U S E

4

Baseplate of Muon Target Chamber in M2 tunnelFebruary 2006

MATERIALS AND LIFE SCIENCE EXPERIMENTAL FACILITY (MLF)

5

Neutron Target

3GeV-RCS Muon Target(Graphite)5 % beam loss

1MW in future500kW at present

Production of the most intense pulsed muon beam all over the world

MUON TARGET AT PROTON BEAM LINE

From RCS and BT Line

To neutron source

To Exp. Hall

To Exp. Hall

To Hot cell

Muon Target at FL1.6m is highly activated. 2-m Iron-shield is required for maintenance Access of worker from maintenance area

(FL 4m- 6m) Replacement by remote handling

Ceiling shield(Movable shield)

Cutting section of proton beam line

4m

6m

10m

1.6m

• Residual radiation dose: 5 Sv/h @surface• Tritium production on target: 0.5 TBq /year @1 MW

MUON PRODUCTION TARGET

7

Fixed target, from 2008 to 2014Lifetime: Irradiation damage of graphite

1 year at 1 MW operation

Rotating target, from 2014Lifetime: BearingsAiming Lifetime: 10 years at 1 MW operation

Target material is polycrystalline graphite, IG-430U.

To extend lifetime, the fixed target was replaced with rotating target that disperse the radiation damage of graphite.

7

1dpa

H. Matsuo, graphite1991 [No.150] 290‐302

CONCEPTUAL DESIGN AT MLF MUSE,BASED ON INSTRUCTION FROM PSI

8

Visit to PSI in 2013 & 2014

Meson Target (E target)

Exchange flask (Cask)

Since Muon Technical Advisory Committee, 2004 Rotating Target, Vacuum chamber, Pillowseal, Cask,,,

Pillowseal

Recent collaboration Investigation of bearing with long lifetime Application to external funding for further collaboration Remote handling, Vacuum application, Industrial technologies,,,

M U O N T A R G E T S Y S T E M

9

In front of Hot cellSeptember 2014

HISTORY OF MUON TARGET SYSTEM

2010 2011 2012 2013 2014 2015 2016 2017 2018 2019

M1/M2

F-Target

R-Target

T system

R. H.

Diagnostic

2003 2004 2005 2006 2007 2008 2009

M1/M2

F-Target

R-Target

T system

R. H.

Design

Design

Design

Construction

Fabrication

Fabrication

Developments & Fabrication

Beam start

Operation

Tests

Operation

Operation

Operation

Developments & Fabrication

Shutdown by

Earthquake

Shutdown by

Hadron A

ccidentHandling of used target

Tests

Tests

RT#1 RT#2FT RT#1Interruption 2 weeks by

trouble on rotation system

Developments & Fabrication Installation

Tests Replacement Replacement Tests Replacement

SC-1#1 SC-1#2

3046

Design

M1/M2 TUNNEL

Movable ceiling shields

Muon target Scraper #1,2 Magnets

Profile monitor & Current transformer

Pillowseal

Maintenance area

Turbo molecular pump

Air-circulation systemClosed with operationOpen w/o operation

M1 tunnel M2 tunnel

To Neutron sourceFrom 3NBT, RCS

FL1.6m

FL4m

FL10m

MUON TARGET SYSTEM

Pillowseal: I.D. 250mm10-8 Pam3/sec.

Thermal spraying of Al

Typical vacuum pressure: 3 x 10-5 PaBlack coating inside the chamber for increment of emissivity

SCRAPERS For beam collimation, two

scrapers are located downstream of muon target.

20 kW beam loss on scraper #1 Thermocouples were affected by

thermal radiation from rotating target. Scraper #1 was replaced with

modified one in September 2015. Measurements of temperature are

appropriate at present.

2 Sv/h @surface

Beam path along beam emittanceTemperature rise: 17 K @ 500kW operation

TRANSFER CASK

Beam Line

Target Assembly

Muon Transfer Cask

Tentative Storage Pod

FL1.6

FL4

FL10

Hot cell

Plug Stand(Exchange position)

Underground Storage RoomNeutron 

Source

MuonTarget Stand

Transportation of radioactive components by Transfer cask

Beam line, Tentative storage pod, Hot cell, Underground storage room, Water-piping drying room Remote –controlled gripper

30-m travel to underground storage room

REMOTE-CONTROLLED REPLACEMENT OF TARGET

Exchange device

Plug stand

rod attachment

In‐cell crane

Power manipulator Master slave

Holding Target rod by two positions

Plug shield

Target rod

Cutting device

Plug stand

Exchange device

Lead window

Long‐term storage vessel

Target rod given to cutting device

Used target rod is replaced with new one in Hot cell. Plug shield is re-used.

Volume reduction by cutting device.

Stored in storage vessel.

M U O N P R O D U C T I O N T A R G E T

16

Muon Fixed Target in beam lineNovember 2013

Muon Fixed Target from 2008 till 2014Isotropic GraphiteIG-430U (Toyo Tanso)Diameter; 70mmThickness; 20mm

P-Beam diameter; 14 mm (2sigma)Design: 4kW heat @ 1MW proton beamIn actual: 1.3 kW @ 333 kW p-beam

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

Titanium layer as stress absorber

Silver brazing method

• Journal of Nuclear Materials 377 (2008) 28-33.• JPS Conf. Proc. , 051002 (2015), DOI

/10.7566/JPSCP.8.051002

70 mm

20 mm

6-years stable operation W/O replacementLifetime: Irradiation damage of graphite

1 year at 1 MW operation

R&D FOR FABRICATION OF MUON FIXED TARGET

HIP method for fabrication of Cu frameCu-SS316L bonding, and Cu-Cu bonding Silver brazing method for graphiteMetallization by 72Ag/26Cu/2Ti in advance

graphite

titanium

brazing material

MUON ROTATING TARGET SINCE 2014

19

P-Beam diameter; 14 mm (2s)4kW heat @ 1MW proton beamThickness of graphite 20 mm

340 mm

Fixed target Rotating target

Proton beam

Rotating target method is applied to distribute the irradiation damage of graphite to a wider area.

Cooling by thermal radiation Lifetime of graphite: 30 years Lifetime is determined by solid

lubricant of bearingsSolid lubricant; Silver coating with MoS2, Lifetime: < 1 year Tungsten Disulfide at J-PARC MLF Aiming lifetime; 10 years

DEVELOPMENTS OF MUON ROTATING TARGET Validation for FEM simulation Duration tests for WS2

lubricants in vacuum & at high temperature.

Actual operation: 15 r.p.m. Accelerated test: 300 r.p.m. Stable operation with 5 x 106

revolutions Finally, rotating target was

installed in 2014.

9 days with 300 r.p.m.

Motor Torque (x 10%)WS2 lubricants

HISTORY OF BEAM OPERATION

By Fixed target

By Rotating target

Oct. 2014

21

Rotating Target without replacement Operational time:17000 hours (Nov. 2014 ~ July. 2019)6000 MWh Rotation : ~16 M revolutions (4.5 M revolutions /year @ 15r.p.m.) Stable 500-kW operation in 1 year

1 MW proton beam operation

Trouble on rotation systemMuon experiment was interrupted for 2 weeks.

R E C E N T P R O G R E S S O FM U O N T A R G E T

22

Scraper replacementSeptember 2015

ALMOST 1-MW OPERATION TESTThe 1-MW operation for 11 hours was successfully completed on 3rd July, 2019

The results showed in good agreement with predictions through the simulations.

Thermal equilibrium

Trouble on Rotation System in 2018

Flexible couplings

Rotating target

Broken flexible coupling

Rotation motor

When rotation feedthrough from air to vacuum was replaced in regular maintenance of 2018, the flexible coupling was broken.

We found the mistake of the machining process.We could replace the broken one. But the problem is that two couplings are used

in the rotating target. The lower one could not be replaced easily.

Continuation of operation by current targetwith upgrade of exhaust of vacuum pump system and diagnostic.

1MW test4(He, HT)

3(He, T, HD, H3)

Buffer tank for tentative storage of exhaustQuadrupole mass spectroscopy

Trial for Replacement of CouplingReplacement of Rotating Target Trial for replacement of coupling (Plan A)Residual radiation dose at coupling position:2 mSv/h @ surface 100 times higher than prediction due to effect of Th. Neutron

ResignAir‐blower to keep negative pressure inside cask

Green house for contamination barrier 

Replacement of target (Plan B)Residual radiation dose at target position:500 mSv/h @ 10 cm

Completed

Commissioning of Plan A in storage pod by cold target Used rotating target in storage pod

by Matoba

Upgrade of Diagnostic system To measure temperature of

rotating target quickly, radiation-hard infrared camera was installed 12-m upstream of target this summer.

The measurements will start in November 2019.

M2 tunnel

Radiation‐hard infrared camera

Successful test under 1 MW operation 

Muon Target

by Matoba

To muon target

M1 tunnel

Position of target chamber in September, 2005

A C K N O W L E D G E M E N T27

S U M M A R Y

28

Thank you so much for your support & collaboration.Keep support & collaboration with Muon group.I will move forward, and you should.

It was a great fun!!