Target Capture for PRISM Koji Yoshimura On behalf
Target & Capture for PRISM Koji Yoshimura On behalf of PRISM Target Group Institute of Particle and Nuclear Science High Energy Accelerator Research Organization (KEK)
Nu. FACT’ 03 June 7 th, 2003, Columbia University Contents n n Targetry for PRISM Solenoid capture Conducting Target Summary
Nu. FACT’ 03 June 7 th, 2003, Columbia University What’s PRISM Pion Capture n n FFAG Phase. Rotator PRISM( Phase Rotation Intense Slow Muon source) A dedicated secondary muon beam channel with high intensity (1011~1012 m/s)and narrow energy spread(a few%) for stopped muon experiments
Nu. FACT’ 03 June 7 th, 2003, Columbia University Requirements of Targetry for PRISM n Pion Momentum n n n ~100 Me. V/c backwards capture scheme available! Emittance n As low as FFAG acceptance n n horizontal 10000 p, vertical 3000 p Method n n Solenoid Capture Conducting Target
Nu. FACT’ 03 June 7 th, 2003, Columbia University Simulation Study of Solenoid Capture n 3 T n n proton Simulation code 12 T field -> 3 T n n 12 T MARS, GEANT 3 n 47 Me. V/c ~ 85 Me. V/c Backward 2000 p ~ 3000 p vertical acceptance
Nu. FACT’ 03 June 7 th, 2003, Columbia University Simulation Results n W n n C Bore (f) n W n Radius(cm) Determined by Capture field YieldµBfield Target radius n C W is better than C B field n Length B Field Target material Thin target is better
Nu. FACT’ 03 June 7 th, 2003, Columbia University SC Solenoid in High Rad. Env n SC Coil Absorber Thick radiation shield is necessary n n n Large bore for absorber n n n High stored energy Expensive magnet To optimize design n n 25 cm, 500 W Thickness of Absorber ~500 W Radiation shield of 25 cm in thickness is needed We totally rely on simulation. Simulation code should be experimentally evaluated!
Nu. FACT’ 03 June 7 th, 2003, Columbia University Direct Measurement of Radiation heat by Beam n Prototype magnet of 10. 9 Tesla n n n Prototype magnet n Beam test with Coil-Mockup n n Beam test at KEK Nov, 2002 n Direct measurement of heat load by radiation Study behavior of magnet under heating condition KEK 12 Ge. V proton n n Temperature rise by radiation heat Hybrid coil (Nb. Ti, Nb 3 Sn, Hi. Tc) Indirect cooling with GM cryocooler 10. 9 T in 6 cm warm bore 1011 protons/s Cryo-calorimeter
Nu. FACT’ 03 June 7 th, 2003, Columbia University Comparison B 12 T 6 T Useful aperture R 0. 05 0. 10 Cryost. IR 0. 55 0. 4 Coil IR 0. 65 0. 45 Coil OR 1. 1 0. 55 ~1. 6 Nb 3 Sn/Nb. Ti Nib. Ti Stored energy ~190 MJ ~16 MJ Coil mass ~20 Ton 2 Ton ~17 M$ ~3 M$ Coil length S/C Cost (Estimate)* *PDG: COST(in M$)=0. 523[E/1 MJ)]0. 662
Nu. FACT’ 03 June 7 th, 2003, Columbia University REALISM n Baseline option n n B=6 T IR=450 cm, L=160 cm Graphite Target L=2λ=80 cm Shield thickness 25 cm Still Necessary for R&D n n Cooling ~500 W Quench protection Radiation safety Thin Graphite target
Nu. FACT’ 03 June 7 th, 2003, Columbia University Further R&D Plan of PRISM Solenoid option n R&D Coil will be constructed this year n n Half or Quarter size Heating using AC LOSS Or Special heater Cooling Method ~500 W n n n Proto-type of graphite target n n Pool boiling Thermo siphon (Using convection) JHF neutrino group (Hayato, Oyabu et. al) Water cooled graphite (40 k. W heat) Thinner Target? Engineering Design -> Future Upgade
Nu. FACT’ 03 June 7 th, 2003, Columbia University Conducting Target n Confine pions inside the target with troidal field n n B. Autin, @Nufact 01 Advantage over Solenoid n n Low emittance beam Linear transport element n n n No SC solenoid channel Cheaper! Cooling condition better?
Nu. FACT’ 03 June 7 th, 2003, Columbia University Comparison of target material n Mercury is good candidate n n Minimum Power Easy to cooling Higher pion yield Technical Issues n n n How to cut off electrical circuit? Stress due to pinch effect Container n n Shockwave Cavitation Thicker wall can be used! n No reabsorption Window
Nu. FACT’ 03 June 7 th, 2003, Columbia University Setup for current test n 1 st phase n n n 2 nd phase n n n 1000 A DC 100 J 250 KA 2. 5 ms Pulse (K 2 K horn PS) 15 KW 3 rd phase n n 1 MW? Beam test?
Nu. FACT’ 03 June 7 th, 2003, Columbia University Mercury Test Loop n n Mercury 18 litter ~ 250 kg Study mercury flow
Nu. FACT’ 03 June 7 th, 2003, Columbia University Summary n Solenoidal Capture n n n Standard scheme Beam test was successfully performed using the mockup Design parameters will be considered. Realistic R&D Model coil Conducting Target n n merits R&D Work has just started! n n Proof of principle Feasibility test of High current liquid target
Nu. FACT’ 03 June 7 th, 2003, Columbia University Basic Priciple Acceptance Proton (Inside the target)
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