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Advanced Meson Science Laboratory Kenta Itahashi

Precision Spectroscopy of Pionic Atoms in ( d , 3 He) Nuclear Reactions. Strong Interaction p -Nucleus ( Chiral symmetry in nuclear matter). Advanced Meson Science Laboratory Kenta Itahashi. Experimental Principle = Missing Mass Spectroscopy. Nuclear reaction to

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Advanced Meson Science Laboratory Kenta Itahashi

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  1. Precision Spectroscopy of Pionic Atoms in (d,3He) Nuclear Reactions Strong Interactionp-Nucleus ( Chiral symmetry in nuclear matter) Advanced Meson Science Laboratory Kenta Itahashi

  2. Experimental Principle = Missing Mass Spectroscopy Nuclear reaction to directly populate pionic atoms. Td=250~300 MeV/u S. Hirenzaki, H. Toki and T.Yamazaki

  3. Calibration 1s Previous experiments and results 2001 GSI Likelihood contour in potential parameters Pion-nucleus interaction is fairly-well determined PRL K. Suzuki et al. 92 (04) 072302

  4. Ambiguity and error can be smaller 2) Likelihood maxima change with different matter radius models Strong interaction potential and nuclear density distribution are coupled. other inputs: c.f. p-scattering data Goals in the 1st experiment 1) Precision can be improved Systematic Study Determine strong interaction and nuclear matter distribution with smaller ambiguity. High Resolution Experimental resolution is improved from 400 keV  < 200 keV (FWHM)

  5. Targets to start systematic study Selection criteria i) Not measured previously ii) Measure chains of isotopes and isotones. iii) First measurement with odd-neutron number nucleus iv) Check whole system by re-measuring 124Sn & 120Sn

  6. F5: focal plane MW Drift Chambers 8 planes, 768 wires < 0.3 mm resolution Target: 5~15 mg/cm2 w. > 5 holders Plastic Scintillation counters F5 – F7: PID TOF and DE Target - F5 Dispersive focus (D=5000 mm) Beam: 250 MeV/u deuteron beam Intensity=1 x 1012/s Dp/p = 1 x 10-3 Experimental Setup BigRIPS as Spectrometer Resolution: ~200 keV (FWHM)

  7. Keys to High Resolution Spectroscopy = Beam Optics Resolution (keV, FWHM) Beam Dp/p 100 Target width 90 Target thickness 140 ----------------------------- ~ 200 If dispersion matching is achieved. TA-F5: F5 position depends only on missing mass in TA SRC-TA: Analyze deuteron beam momentum ~140 F5 Target

  8. Preparation Status and Schedule (slightly changed due to budget situation) Beam optics Beam property measurement

  9. Summary Study of pionic atoms has been yielding fruitful results on the p-nucleus s-wave interaction, with interesting implications for the study of chiral restoration in a nuclear medium. Theoretical evaluation of expected cross section is reliable and is ongoing. (Nara Women's Univ. theory group) RIBF is the most suitable facility to proceed the study and to perform the systematic spectroscopy. Systematic study is expected to lead to smaller ambiguities in determination of the strong interaction and nuclear matter distribution. Preparation is now in progress.

  10. Human Resources RIKEN (Iwasaki-lab) + Tokyo Tech. K. Itahashi, M. Iwasaki, H. Ohnishi, S. Okada, H. Outa, M. Sato, T. Suzuki, T.Yamazaki (Detectors + Electronics + Gas handling) RIKEN (Accelerator) M. Wakasugi, Y. Yano, (Collinear Laser Spectroscopy) GSI (FRS-group) H. Geissel, C. Nociforo, H. Weick (Beam Optics Calculation and Test) University of Tokyo R.S. Hayano, S. Itoh, N. Ono, H. Tatsuno, (Physics + Detectors) Nara Women’s University S. Hirenzaki, R. Kimura, J. Yamagata Stefan Meyer Institute P. Kienle, K. Suzuki (Target + Physics) Stockholm University P.E. Tegner, K. Lindberg, I. Zartova (Detectors + Electronics + Gas handling)

  11. Spare

  12. Realistic Numbers Trigger Condition SCF5 × SCF7 ⇒ ~200 Hz (5 mg/cm2 target + 1012/sec beam) c.f. background proton  0.25 MHz Readout Electronics + DAQ MWDC: 8 planes x 48 wires x 2 sets = 768 ch (TDC) 16ch PreAmp + Amp = newly designed by KEK ⇒ fed to VME 64ch TDC (AMT-KEK) Scintillation counters: 20 ch (QDC+TDC) ⇒ fed to VME 16ch QDC & 16ch TDC (CAEN) Remote Controllable Modules (Since we have no access to the cave) Camac? ⇒ Presently no idea.

  13. Physics Motivation (Strong interaction) A=1 p-hydrogen, p-deuterium high precision spectroscopy DB/B < 1 % @ PSI PLB469(99)Schroeder et al. b0= 0.0016 +-0.0013 b1=-0.0868+-0.0014

  14. Four step calibration of incident energy in 100 keV precision Step 0. Set BigRIPS to primary deuteron beam rigidity Step 1. Measure 12C3+ beam velocity by Collinear laser spectroscopy. Step 2. Calibrate BigRIPS by measuring 12C3+ beam position at focus. Step 3. Keep BigRIPS and measure deuteron beam position at focus. deuteron K=500 MeV p=1457.9 MeV/c 12C3+ z=3, p/z = 1457.9 MeV/c therefore p = 4373.85 MeV/c --> K = 825.48 MeV beta = 0.61371 gamma = 1.26658 relativistic doppler correction w' = w * gamma (1 + beta cos theta) 12C3+ transition 0.293 Hartree (J. Phys. B: At Mol Opt Phys 34 (2001) 1079-1104 M.Godefoid ) ----> w = 7.969 eV (1 hartree = 27.211 eV) w' = 5.442 eV -> 231 nm So, what we need is 231 nm laser and 12C3+ 825 MeV (=70 MeV/u).

  15. How to measure the beam energy? Collinear laser spectroscopy 10-6 accuracy of b is possible. Systematic error reduced. NIM A419 (98) 50. Wakasugi et al.

  16. Antiproton absorption measurement  neutron density distribution

  17. Pionic atoms are sensitive to nuclear radii 2 param. Fermi model

  18. Nuclear Absorption Stopped pion method does not work effectively to investigate “deeply bound pionic states” where pion and nucleus has large overlap.

  19. Let me talk more about technical details… What was the beam energy? GSI-SIS Systematic error arising from uncertainty in the beam energy is large. 0.1 % momentum drift

  20. Physics Motivation (Strong interaction) A=1 p-hydrogen, p-deuterium high precision spectroscopy DB/B < 1 % @ PSI PLB469(99)Schroeder et al. b0= 0.0016 +-0.0013 b1= -0.0868+-0.0014

  21. Cost Estimation (kYen) MWDC 6,000 PreAMP + Amp 2,000 VME TDC (LVDS) 4,500 VME Crate + Master 1,400 VME QDC + TDC 1,200 NIM Modules 2,600 MWDC HV 1,500 PMT HV 1,000 Cables 800 Camac? 1,200 Segmented Scintillator 1,000 PMT 2,000 Gas system 1,000 --------------------------------------- 26,200

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