j-parc upgrade t. nakadaira (kek / j-parc). outline j-parc overview & on-going program...
TRANSCRIPT
J-PARC upgrade
T. Nakadaira
(KEK / J-PARC)
Outline
J-PARC overview & on-going program
Motivation of future experiment in J-PARC
Overview of future experiment proposals
Accelerator upgrade plan
Is J-PARC beam-line ready for higher power?
Bird’s eye photo in July. 2009
Linac181MeV
RCS(Rapid Cycling Synchrotron)3GeV
T2KNeutrino Monitor
MR(Main Ring Synchrotron)30GeV
Slow Extraction Experimental Facility
J-PARC Accelerator and Experimental Facility
Muon Monitorfor
Neutrino Beam
Target Stationfor
Neutrino BeamNeutrino Beam
Material and Life Science Experimental Facility
Fast Extraction neutrino Facility
On-going experiment: T2K
280m
Near Detector
Pure beam
Completed Experiment
Running experiment
Conventional beam: protons + Graphite target pions or is focused selectively
by 3 electromagnetic horns. or
Pseudo-Monochromatic beam by Off-Axis method (ref. BNL E899)
Set peak of ( flux CC ) @ oscillation max. Fraction of high energy neutrino is small.
OA3
OA0
OA2OA2.5
energy spectrum (flux Cross Section)
Oscillation Prob.@ L=295kmm2=2.510-3, 3.010-3[eV2]
OA = 2.5 is selected for T2K
( ) Near Detector
Beam dump-monitor
Decay Volume
Target &horn
Extraction point
280m
SK
OA
RCS
MR
J-PARC-beam line
Current beam operation
Future program @ J-PARC
KEK road map says …
Quest for the Origin of Matter Dominated UniverseQuest for the Origin of Matter Dominated Universe
One of the Main Subject of the One of the Main Subject of the KEK RoadmapKEK Roadmap
Discovery of Lepton CP Violation
Proton Decay
Discovery of the e Appearance
Neutrino Intensity Improvement
Huge Detector R&D
T2K(2009~)
Water Cherenkovv
Liquid Ar TPC
Establish Huge Detector
Technology
Construction of Huge Detector
Lepton Sector CP Violation
Effect of CP Phase appear as– e Appearance Energy Spectrum Shape *Peak position and height for 1st, 2nd maximum and minimum *Sensitive to all the non-vanishing including 180°
*Could investigate CP phase with run only
– Difference between e and e Behavior • Sensitive to any mechanism to make asymmetry• Separation from possible sources of non-CPV asymmetry needed
12 13 13 12 13 1
12 23 12 13 23 12 23 12 13 23 13 23 2
12 13 23 12 23 12 13 23 12 23 13 23 3
ie
i i
i i
c c c s e s
s c e c s s c c e s s s c s
e c s c s s e s s c c s c c
Angle and Baseline
OA3°
OA0°OA2°
OA2.5°
f
lux
• Off-axis angle– On-Axis: Wide Energy Coverage, ○ Energy Spectrum Measurement × Control of Background– Off-Axis: Narrow Energy Coverage, ○ Control of Background × Energy Spectrum Measurement → Counting Experiment
• Baseline– Long: ○ 2nd Osc. Max. at Measurable Energy × Less Statistics ? Large Matter Effect– Short: ○ High Statistics × 2nd Osc.Max.Too Low Energy
to Measure ? Less Matter Effect (E/L)
CP=90CP=270
CP=0
m312 = 2.5x10-3 eV2
sin2213 = 0.1No matter effects
νμ νe oscillation probability
Osc
illa
tion
pro
babi
lity
10
P32 proposal (Lar TPC R&D)Recommended by J-PARC PAC(Jan 2010), arXiv:0804.2111
Kamioka L=295km OA=2.5deg
Okinoshima L=658km OA=0.78deg
“Available” technologies for huge detector
Liq Ar TPCAim O(100kton)Electronic “bubble chamber”
Can track every charged particleDown to very low energy
Neutrino energy reconstruction by eg. total energy
No need to assume process typeCapable upto high energy
Good PID w/ dE/dx, pi0 rejection
Water CherenkovAim O(1000kton)Energy reconstruction
assuming CcqeEffective < 1GeV
Good PID (/e) at low energyCherenkov threshold
Good at Wideband beam
Good at low E (<1GeV) narrow band beam
How about accelerator power?
Circumference 1567.5 mRepetition rate ~ 0.3 Hz@Start UpInjection energy 3 GeVExtraction energy 30 GeVSuperperiodicity 3Harmonic # 9No. of bunches 8Transition 31.7(imaginary)Typical tune 22.4, 20.8Transverse emittance At injection ~54 mm-mrad At extraction ~10 mm-mradDesign Beam power 0.75MW upgrade
Three dispersion free straight sections of 116-m long: - Injection and collimator systems - Fast extraction (beam is extracted inside/outside of the ring) and RF cavities inside: Neutrino Beamline outside: Beam abort line - Slow extraction to Slow extraction Experimental Facility
Design of MR
MR power improvement scenario
15
RCSMRBeam transfer fraction
MR Power Improvement ScenarioMR Power Improvement Scenario toward MW-class power frontier machine toward MW-class power frontier machine
― KEK Roadmap ―Day1(up to Dec.2010)
Next Step KEK Roadmap
Power(MW) 0.11 0.45 >1.66
Energy(GeV) 30 30 30
Rep Cycle(sec) 3.2 2.2 1.92~ 0.5
No. of Bunch 8 8 8
Particle/Bunch ~1×1013 2.5×1013 4.1~ 8.3×1013
Particle/Ring 7.7×1013 2.0×1014 3.3~ 6.7×1014
LINAC(MeV) 181 181 400
RCS h=2 h=2 h=2 or 1
Combination of High rep. cycle and High beam density
Achieved !
Items for Acc. upgrade
Ion source & Front-end LINAC energy 181 400MeV Current design 30mA 50mA
RF systemR&D for High Vgap RF is in progress
MR power supply for rapid cycle operation. Downsizing & distributed system
• Ex. Power-supply for MR bending magnet: 6 24
Beam-loss managementCollimator shield should be reinforced.
beam-line is ready for 1.6MW beam?
Primary proton beam-line
Bend the beam by ~80 Using Super-conducting combined function Magnets
NC magnets Using MIC (Mineral-insulation-cable)
Beam profile monitorBeam position monitor
Secured operation is important for high intensity beam.Allowable beam loss: ~1W/m.
Baffle
1st horn Target
OTR(Profile monitor)
2nd horn 3rd horn
BEAM
Iron shield (2.2m)
Concrete Blocks
Helium Vessel
Decay Volume
110m
Beam dump
MuonMonitor
Target station
Beam window
Secondary beam-line
target
Points for beam-line for 1.6MW
J-PARC beam-line can handle 1.6MW beam by improving of each equipments!
Strength of the equipments which are exposed with beam directly: Target, beam window, Profile monitor.
• Thermal shock is proportional to # of protons / pulse. It is OK for power upgrade by increasing the cycle.
• Cooling power should be improved. Cyclic fatigue for the horn, target, etc increases.
• Lifetime / Maintenance cycle may be shortened. Improving the remote maintenance, Cost-down of the equipments is important.
Radiation protection• Thickness of tunnel wall for TS / DV / Dump is OK for 3~4MW. • The activation of equipments / cooling water / air of area, etc is
proportional to beam power. It may necessary to improve the air ventilation / drainage water system
to increase the dilution rate.
Summary
Main goal of future experiment at J-PARC Search for CP violation in oscillation.
Future experiment proposals LAr TPC @ ~660km
• On-axis, Measure the 2nd oscillation maximum Hyper-K @ ~300km
• Off-axis, Measure and anti- difference
J-PARC: Accelerator & beam-lineCurrent: 30GeV, ~120kW beam supplied to T2K
Aiming ~400kW in 2012 in current power-up scenario J-PARC upgrade plan
~1.7MW by improving the each components.Strategy: Increasing the repetition rate & protons/pulse.