(KEK / J-PARC)
J-PARC overview & on-going n program
Motivation of future n experiment in J-PARC
Overview of future n experiment proposals
Accelerator upgrade plan
Is J-PARC n beam-line ready for higher
J-PARC Accelerator and Experimental Facility
181MeV (Rapid Cycling Synchrotron)
Neutrino Beam for
for Fast Extraction
Neutrino Monitor neutrino Facility
Material and Life Science
(Main Ring Synchrotron)
Bird’s eye photo in July. 2009 Experimental Facility
On-going n experiment: T2K
Pure nm beam
J-PARC n-beam line
Conventional nm beam:
protons + Graphite target pions
p+ or p- is focused selectively
by 3 electromagnetic horns.
p+ m+ + nm or p- m- +nm
by Off-Axis method (ref. BNL E899) Extraction point
Set peak of ( flux sCC ) @ oscillation max.
Fraction of high energy neutrino is small.
Dm2=2.510-3, Decay Volume
nenergy spectrum (flux Cross Section)
OA0 Beam dump
OA = 2.5 m-monitor
OA2 is selected
for T2K 280m OA
OA2.5 n Near Detector
Current beam operation
Future n program @ J-PARC
KEK road map says …
Quest for the Origin of Matter Dominated Universe
One of the Main Subject of the
T2K Discovery of
(2009~) the ne Appearance
Neutrino Lepton CP Violation
Establish Proton Decay
Huge Detector R&D Huge Detector Construction of
Technology Huge Detector
Water Cherenkov Liquid Ar TPC
Lepton Sector CP Violation
n e c12 c13 c13 s12 e - id s13 n 1
n m - s12 c23 - e - id c12 s13 s23 c12c23 - eid s12 s13 s23 c13s23 n 2
n -eid c s c + s s -eid s12 s13c23 - c12 s23 c13c23 n 3
12 13 23 12 23
Effect of CP Phase d appear as
– ne Appearance Energy Spectrum Shape
*Peak position and height for 1st, 2nd maximum and minimum
*Sensitive to all the non-vanishing d including 180°
*Could investigate CP phase with n run only
– Difference between ne and ne Behavior
• Sensitive to any mechanism to make asymmetry
• Separation from possible sources of non-CPV asymmetry needed
Angle and Baseline
• Off-axis angle OA0°
– On-Axis: Wide Energy Coverage, OA2°
○ Energy Spectrum Measurement
× Control of p0 Background
– Off-Axis: Narrow Energy Coverage,
○ Control of p0 Background OA3°
× Energy Spectrum Measurement
→ Counting Experiment
νμ νe oscillation probability
○ 2nd Osc. Max. at Measurable Energy
× Less Statistics
? Large Matter Effect
– Short: Dm312 = 2.5x10 eV2
○ High Statistics sin22q13 = 0.1
No matter effects
× 2nd Osc.Max.Too Low Energy
? Less Matter Effect
Kamioka L=295km OA=2.5deg
Okinoshima L=658km OA=0.78deg
P32 proposal (Lar TPC R&D)
Recommended by J-PARC PAC
(Jan 2010), arXiv:0804.2111
“Available” technologies for huge detector
Liq Ar TPC Water Cherenkov
Aim O(100kton) Aim O(1000kton)
Electronic “bubble chamber” Energy reconstruction
Can track every charged particle assuming Ccqe
Down to very low energy Effective < 1GeV
Neutrino energy reconstruction Good PID (m/e) at low energy
by eg. total energy Cherenkov threshold
No need to assume process type
Capable upto high energy
Good PID w/ dE/dx, pi0
Good at low E (<1GeV)
rejection narrow band beam
Good at Wideband beam
How about accelerator power?
Design of MR
Circumference 1567.5 m
Repetition rate ～0.3 Hz@Start Up
Injection energy 3 GeV
Extraction energy 30 GeV
Harmonic # 9
No. of bunches 8
Typical tune 22.4, 20.8
At injection ~54 pmm-mrad
At extraction ~10 pmm-mrad
Design 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
MR power improvement scenario
Beam transfer fraction 15
MR Power Improvement Scenario
toward MW-class power frontier machine
― KEK Roadmap ―
Day1 Achieved ! 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
Items for Acc. upgrade
Ion source & Front-end
LINAC energy 181 400MeV
Current design 30mA 50mA
R&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
Collimator shield should be reinforced.
n beam-line is ready for 1.6MW beam?
Primary proton beam-line
Bend the beam by ~80
combined function Magnets
Beam position monitor Beam profile monitor NC magnets
Secured operation is important for high intensity beam.
Allowable beam loss: ~1W/m.
Target station Secondary beam-line
1st horn Target
2nd horn Baffle
target (Profile monitor)
Points for n beam-line for 1.6MW
J-PARC n 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
• 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.
Main goal of future n experiment at J-PARC
Search for CP violation in n oscillation.
Future n experiment proposals
LAr TPC @ ~660km
• On-axis, Measure the 2nd oscillation maximum
Hyper-K @ ~300km
• Off-axis, Measure n and anti-n difference
J-PARC: Accelerator & n beam-line
Current: 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.