J-PARC Accelerator and Experimental Facility

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J-PARC Accelerator and Experimental Facility Powered By Docstoc
					J-PARC upgrade


    T. Nakadaira
  (KEK / J-PARC)
                  Outline
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
 power?
                     J-PARC Accelerator and Experimental Facility
                                               Linac                RCS
                                               181MeV               (Rapid Cycling Synchrotron)
                                                                    3GeV

                                                                            Target Station
       Neutrino Beam                                                              for
                                                                            Neutrino Beam


                            Muon Monitor
        T2K
                                  for                                             Fast Extraction
  Neutrino Monitor                                                                neutrino Facility
                            Neutrino Beam
                                            Material and Life Science
                                             Experimental Facility




 MR
 (Main Ring Synchrotron)
 30GeV

                                             Slow Extraction
Bird’s eye photo in July. 2009              Experimental Facility
On-going n experiment: T2K

         Running experiment




                                   Near Detector

                              Pure nm beam

                                          280m
         J-PARC n-beam line
                                                                                        MR

                                                                          RCS



Conventional nm beam:
    protons + Graphite target  pions
    p+ or p- is focused selectively
    by 3 electromagnetic horns.
    p+  m+ + nm or p-  m- +nm
Pseudo-Monochromatic beam
 by Off-Axis method (ref. BNL E899)                                             Extraction point
   Set peak of ( flux  sCC ) @ oscillation max.
   Fraction of high energy neutrino is small.
                                                                               Target &horn
                     Oscillation Prob.
                     @ L=295km
                     Dm2=2.510-3,                                             Decay Volume
                          3.010-3[eV2]
     nenergy spectrum   (flux  Cross Section)
                                OA0                                            Beam dump
                                                  OA = 2.5                     m-monitor
                 OA2                             is selected
                                                  for T2K       280m OA
                OA2.5                                                         n Near Detector
                (OA3)
                                                                          SK
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
                                KEK Roadmap


         T2K                 Discovery of
         (2009~)          the ne Appearance


                                                            Discovery of
       Neutrino                                          Lepton CP Violation
Intensity Improvement
                          Establish                         Proton Decay
 Huge Detector R&D      Huge Detector Construction of
                         Technology   Huge Detector
                         v
         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




                                                                          nm flux
•   Off-axis angle                                                                                          OA0°
     – On-Axis: Wide Energy Coverage,                                                   OA2°
         ○ Energy Spectrum Measurement
         × Control of p0 Background
     – Off-Axis: Narrow Energy Coverage,
                                                                                                OA2.5°
         ○ Control of p0 Background                                                              OA3°
         × Energy Spectrum Measurement
                    → Counting Experiment
•   Baseline
     – Long:


                                                Oscillation probability
                                                                                    νμ  νe oscillation probability
         ○ 2nd Osc. Max. at Measurable Energy
                                                                                                           dCP=0
         × Less Statistics
                                                                                                           dCP=90
         ? Large Matter Effect
                                                                                                           dCP=270
     – Short:                                                                                        Dm312 = 2.5x10 eV2
                                                                                                                 -3

         ○ High Statistics                                                                           sin22q13 = 0.1
                                                                                                     No matter effects
         × 2nd Osc.Max.Too Low Energy
                to Measure
         ? Less Matter Effect
                                                                                                                  10
                                                                                                                 (E/L)
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
Superperiodicity 3
Harmonic #        9
No. of bunches    8
Transition       31.7(imaginary)
Typical tune      22.4, 20.8
Transverse emittance
  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




               RCSMR
               Beam transfer fraction   15
       MR Power Improvement Scenario
    toward MW-class power frontier machine
            ― KEK Roadmap ―
                     Day1 Achieved !   Next Step   KEK Roadmap
                     (up to
                     Dec.2010)
    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
RF system
 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
Beam-loss management
 Collimator shield should be reinforced.
n beam-line is ready for 1.6MW beam?
             Primary proton beam-line



                                                          Bend the beam by ~80
                                                          Using Super-conducting
                                                          combined function Magnets

Beam position monitor     Beam profile monitor            NC magnets
                                                          Using MIC
                                                          (Mineral-insulation-cable)




Secured operation is important for high intensity beam.
Allowable beam loss: ~1W/m.
                    Target station   Secondary beam-line
                                                                   Beam dump
                                            Decay Volume
                                                                              Muon
                                                                              Monitor

Beam window

                                        110m



                                                                   1st horn    Target




               2nd horn                    Baffle




                                               OTR
      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
      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 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.

				
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posted:9/5/2011
language:Indonesian
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