Target & Capture for PRISM

Koji YoshimuraOn behalf of PRISM Target Group

Institute of Particle and Nuclear ScienceHigh Energy Accelerator Research Organization

(KEK)

NuFACT’03June 7th, 2003, Columbia University

ContentsTargetry for PRISMSolenoid captureConducting TargetSummary

NuFACT’03June 7th, 2003, Columbia University

What’s PRISM

PRISM( Phase Rotation Intense SlowMuon source)

A dedicated secondary muon beam channel with high intensity(1011~1012µ/s)and

narrow energy spread(a few%) for stopped muon experiments

PROTON BEAM DUMP

CAPTURE

SOLENOID

PRODUCTION TARGET

PRIMARY PROTON

MATCHING

SECTION SOLENOID

FFAG RING

RF CAVITY

5 M

INJECTION SYSTEM

EJECTION SYSTEM

Pion Capture

FFAGPhaseRotator

NuFACT’03June 7th, 2003, Columbia University

Requirements of Targetry for PRISM

Pion Momentum~100 MeV/cbackwards capture scheme available!

EmittanceAs low as FFAG acceptance

horizontal 10000π, vertical 3000π

MethodSolenoid CaptureConducting Target

NuFACT’03June 7th, 2003, Columbia University

Simulation Study of Solenoid CaptureSimulation code

MARS, GEANT312 T field -> 3T

47MeV/c ~ 85 MeV/cBackward2000 π ~ 3000 π vertical acceptance

proton

~10 cm

B(high) typ. : 16T

B(low) typ. : 4T

field matching region

B

target(tungsten : 2~3 Interaction Length)

~0.1 radian

Shielding Material

Shielding Material

B

R > R B /Blow lowhigh high

22

proton

12 T

3 T

NuFACT’03June 7th, 2003, Columbia University

Simulation ResultsTarget material

W is better than C

B fieldDetermined by Capture fieldYield∝Bfield

Target radiusThin target is better

DATA Summmary

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Target Length

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diameter of Warm bore

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B fiel d

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024 6

Target Radius

C

W

C

W

B Field Radius(cm)

Length Bore (φ)

NuFACT’03June 7th, 2003, Columbia University

SC Solenoid in High Rad. EnvThick radiation shield is necessary

~500 WRadiation shield of 25 cm in thickness is needed

Large bore for absorberHigh stored energyExpensive magnet

To optimize designWe totally rely on simulation.Simulation code should be experimentally evaluated!

AbsorberSC Coil

Thickness of Absorber

25 cm, 500W

NuFACT’03June 7th, 2003, Columbia University

Direct Measurement of Radiation heat by Beam

Prototype magnet of 10.9 TeslaHybrid coil (NbTi, Nb3Sn, HiTc)Indirect cooling with GM cryocooler10.9 T in 6 cm warm bore

Beam test with Coil-MockupDirect measurement of heat load by radiationStudy behavior of magnet under heating conditionKEK 12 GeV proton

1011 protons/sCryo-calorimeter

Prototype magnet

Temperature rise by radiation heat

Beam test at KEK Nov, 2002

NuFACT’03June 7th, 2003, Columbia University

Comparison

2 Ton~20 TonCoil mass

~3 M$~17 M$Cost (Estimate)*

~16 MJ~190 MJStored energy

NibTiNb3Sn/NbTiS/C

~1.6~1.6Coil length

0.551.1Coil OR

0.450.65Coil IR

0.40.55Cryost. IR

0.100.05Useful aperture R

6 T12 TB

*PDG: COST(in M$)=0.523[E/1 MJ)]0.662

NuFACT’03June 7th, 2003, Columbia University

REALISM

Baseline optionB=6TIR=450 cm, L=160 cmGraphite Target L=2λ=80 cmShield thickness 25cm

Still Necessary for R&DCooling ~500 WQuench protectionRadiation safetyThin Graphite target

NuFACT’03June 7th, 2003, Columbia University

Further R&D Planof PRISM Solenoid option

R&D Coil will be constructed this yearHalf or Quarter sizeHeating using AC LOSSOr Special heaterCooling Method ~500W

Pool boilingThermo siphon (Using convection)

Proto-type of graphite targetJHF neutrino group (Hayato, Oyabu et.al)Water cooled graphite (40 kW heat)Thinner Target?

Engineering Design -> Future Upgade

NuFACT’03June 7th, 2003, Columbia University

Conducting TargetConfine pions inside the target with troidal field

B. Autin, @Nufact01Advantage over Solenoid

Low emittance beamLinear transport element

No SC solenoid channelCheaper!

Cooling condition better?

NuFACT’03June 7th, 2003, Columbia University

Comparison of target material

Mercury is good candidateMinimum PowerEasy to coolingHigher pion yield

Technical IssuesHow to cut off electrical circuit?Stress due to pinch effect Container

ShockwaveCavitationThicker wall can be used!

No reabsorptionWindow

NuFACT’03June 7th, 2003, Columbia University

Setup for current test

1st phase1000 A DC100 J

2nd phase250 KA 2.5ms Pulse (K2K horn PS)15 KW

3rd phase1 MW?Beam test?

NuFACT’03June 7th, 2003, Columbia University

Mercury Test LoopMercury 18 litter ~ 250 kgStudy mercury flow

NuFACT’03June 7th, 2003, Columbia University

Summary

Solenoidal CaptureStandard schemeBeam test was successfully performed using the mockupDesign parameters will be considered.Realistic R&D Model coil

Conducting TargetmeritsR&D Work has just started!

Proof of principleFeasibility test of High current liquid target

NuFACT’03June 7th, 2003, Columbia University

Basic Priciple

B ∝ r(Inside the target)

ProtonAcceptance