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J-PARC での YN 相互作用の研究

J-PARC での YN 相互作用の研究. 東北大学理学研究科 三輪浩司. Contents. Physics background YN interaction Scattering experiment , spectroscopy Past experiments of YN scattering What did we learn?. What should we improve? Experiment at J-PARC LH 2 , Fast IIT, Scifi-MPPC R&D of Scifi-MPPC

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J-PARC での YN 相互作用の研究

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  1. J-PARCでのYN相互作用の研究 東北大学理学研究科 三輪浩司

  2. Contents • Physics background • YN interaction • Scattering experiment , spectroscopy • Past experiments of YN scattering • What did we learn?. What should we improve? • Experiment at J-PARC • LH2, Fast IIT, Scifi-MPPC • R&D of Scifi-MPPC • Performance for MIP, proton • e+ beam test @ LNS • proton beam test @ CYRIC • Outlook • Trigger, Multi-channel readout

  3. Nuclear force What is the origin? Color magnetic interaction meson exchange picture NN interaction To SU(3) flavor symmetry • More exchange • mesons • K • K*,   interaction Isospin 3/2 Spin 1 Quark Pauli effect Strong repulsive force

  4. Baryon-Baryon interaction • NN interaction • special aspect of BB interaction • BB interaction • Effect of new quark • Different aspect of u,d quarks • N •  exchange is forbidden. • N • (S,T)=(1,3/2) quark Pauli effect S=0 NN(T=1) S=-1 N(T=3/2)N-N(T=1/2) S=-2 (T=2) N--(T=1) N--(T=0) S=-3 (T=3/2) -  (T=1/2) S=-4 (T=1) S=0 NN(T=0) S=-1 N-N(T=1/2) S=-2 N-(T=1) S=-3 (T=3/2) S=-1 N(T=3/2) S=-2 N--(T=1) S=-3-  (T=1/2) S=-4 (T=0) S=-1 N-N(T=1/2) S=-2 N-(T=1) N--(T=0) S=-3 -  (T=1/2) S=-1 N-N(T=1/2) S=-2 N-(T=1) N(T=0) S=-3 -  (T=1/2) S=-2 N--(T=0)

  5. 2body interaction pp, np scattering deuteron Tensor force Spin dependent force Structure of Nuclei Large LS force Polarized pp, np scattering 2body interaction Bubble chamber Poor data SU(3) framework Spin dependent force Structure of  Hypernulei npnp pppp pp p0p p+p pp p0n pn × Experimental investigation of YN interaction NN interaction 1950 YN interaction 70 At J-PARC! 90

  6. p scattering HC-D HC-F RGM-F NSC YN scattering observables • Precise measurement • Model selection • Meson exchange model • Quark model

  7. YN scattering experiment at KEK • N(N)=N(beam)/10000 • More Hyperon beam • More fast imaging

  8. Important parameter • Production of  • 1cm Scifi (CH) (from free proton) • 1M/spill beam • KURAMA spectrometer acceptance • (, ) 1.8mb  9  / spill • (, ) 0.5mb  2  / spill • Scattering of  • Mean flight legth ~ 1.3cm • (p) ~ 10mb (assumption) • 1600  1 p scattering

  9. Important parameter2 • Production target • 2cm CH2 + 2cm CH • Free proton 54  • Quasi free 118  @ 1M K 1M/spill 10M/spill (, ) 5M/spill 50M/spill 500M/spill 5000M/spill (, )  172/spill 1720/spill 17200/spill 172000/spill p scat 10/spill 100/spill 0.1/spill 1/spill We need Fast Imaging device We need high quality trigger

  10. R&D works for fast imaging • Ieiri • High-Speed Image Delay Tube • Image duration • Electron drift • J.K. Ahn • LH2 target (No Imaging) • Detect all state particle with spectrometer • Miwa • Scifi-MPPC readout • Fast imaging + spectrometer

  11. Read out system of SCIFI using MPPC’s • Multi-Pixel Photon Counter (MPPC) • New Si photo-diode consisted of multipixel of Avalanche Photo Diode (APD) operating in Geiger Mode • 100～1600 pixels of APD in MPPC • Output signal is the sum of each pixel • Characteristics • Fast time response ( < 10ns) • It can operate in the high beam intensity • Large gain (105106) • Possible to detect 1 photon • Operation at the magnetic field • IIT can not work at the magnetic field 1mm 1mm Can we use this detector for hyperon scattering experiment using a high intensity beam ?

  12. Concept of whole experimental setup • At J-PARC • 1st target is p scattering •  production via (, ) reactionusing a 1.1GeV/c K- beam • Forward spectrometer＋Cylindrical spectrometer Zoom up

  13. MIP Light yield Enough efficiency Slow proton Dynamic range Range analysis Total energy deposit     p     p To be studied

  14. Performance check for MIP LNS-Tohoku, test beam line With 450MeV Positron beam 2007/Jan 20ch MPPC readout

  15. Performance for MIP particle • Prototype of Scifi-MPPC system • Readout of 20ch MPPC 1mmx1mm Fiber 20 ch e+ beam MPPC Connection between Fiber and MPPC MPPC Scinti. Fiber Fiber

  16. Photon number for MIP • Identification of beam • Required hits of upstream and downstream fibers Required these hits  two photon Check the photon number

  17. Performance for proton Tohoku Univ. CYRIC 80MeV proton beam 2008/June 50ch readout

  18. Purpose of this experiment • Response of Scifi-MPPC system for proton • Light yield • Momentum resolution from Range • Radiation hardness • Momentum range of proton in YN scattering exp. • Total 0~1.2GeV/c • Stop in Scifi 0~0.4GeV/c • This momentum range is accessible in CYRIC (80MeV proton)

  19. Experimental setup • Primary Proton beam • Ekin = 77.52 MeV • 1~5nA • Secondary proton beam • pp scattering (11~42MeV) • Primary target • CH2 • 30, 100, 300 m • Fiber bundle • 5segment x 10 layer • 1mmx1mm • Vacuum chamber • 10-3 Pa Fiber 5segment x 10layer 20cm from target Trigger counter 12cm from target Entrance 3mm p’ p 77.52MeV p

  20. Trigger counter p CH2 target p p beam 77MeV Scifi Data List pp scattering Momentum selected proton beam to Scifi Angle scan

  21. (single photon ~ 4mV) 40ns ~250mV Proton pass through Signal of proton • Raw signal • Proton ~250mV • 1p.e. ~4mV • Dynamic range (400pixel) • 1p.e. (1pixel) ~ 10ch • 34MeV proton ~ 120pixel • Stopping proton ~ 300pixel • Trigger selection • Proton  OK • Stopping proton  OK Proton stop MIP region

  22. Stop layer and Total energy deposit Stop layer Total energy

  23.     p Trigger possibility • Identify of scattering proton • Total Energy deposit • 1 scattering / 100 cut events ( >22MeV) • Number of particle + each energy deposit 2 particles  Counter 1 stopping particle Energy deposit Detect 3 particles with counter

  24. Multi-channel readout • Total channel of MPPC • ~5000 ch • We have to serialize the readout (like SSD). • Serializing chip  Flash ADC • Requirement of serialize • Fast time response • 10MHz • Trigger generation • Chip • VA chip? (slow?) • APV25 (50ns peaking time)

  25. Summary • We want to reveal new aspects of B.B. interaction • N, N, N • We need high intensity beam •  ~10MHz,  ~ 100MHz • We have to develop high speed imaging device • Fast image delay tube • MPPC readout • MPPC readout • MIP • mean photon number ~6 photon • Proton • Dynamic range is enough. • Works well as range counter. • Stopping proton can be triggered easily. • Further works • Trigger possibility • Multi-channel read out

  26. Typical image (Ekin=30MeV)

  27. YN scattering experiment at KEK • Scintillation fiber and IIT-CCD • KEK-PS E289, E452 • p, p, p elastic scattering • Feasibility of SCIFI active target • Problem • IIT-CCD is slow • There are overlaps of image @ beam intensity > 300kHz • Detection of all particles in the final state is difficult

  28. npnp pppp pp p0p p+p pp p0n pn Experimental investigation of YN interaction • Hyperon-Nucleon Scattering • Difficult due to short lifetime of hyperon • Poor data compared to NN scattering • Structure of  hypernuclei • High resolution magnetic spectrometer • Gamma-ray spectroscopy using Ge detector • Problem • Derive two body force from complex many body system • N interaction, N interaction？

  29. 大きさについて

  30. Free proton Quasi free scattering  (degree) Momentumproton(GeV/c)   n from    + from  Scattered p Advantage of detecting all particles in the final state • Remove the quasi free scattering • SCIFI consists of CH • Quasi-free scattering with proton in carbon nuclei should be separated from the scattering with free proton. Prediction Proton: Mom, Angle p Consistency check Remove quasi free Measurement Scat’  : Momentum Measurement Scat’ angle Proton: Mom, Angle

  31. Photon number for MIP • Mean photon number ~6 photon • Efficiency ( > 2 photon) ~ 95% Mean photon number > 2photon > 1photon

  32. Operation in Magnetic Field Magnet • Photon number with magnetic field • Photon number • Gain e+ beam B Field Fiber Do NOT change due to the magnetic field We can use this Scifi-MPPC system as an imaging detector inside the magnetic spectrometer

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