Elastic Scattering of Protons with RI Beams

Transcription

1 Elastic Scattering of Protons with RI Beams Contents 1. Motivation 2. Recoil Proton Spectrometer 3. Experiments: 9,10,11 C, 66,70 Ni 4. Summary Y.Matuda Tohoku University GCOE symposium 2011 February 18, 2011 Tohoku University

2 Elastic Scattering of Protons with RI beam (ESPRI) project Collaborators S.Terashima (GSI) J.Zenihiro (RCNP) H.Sakaguchi (RCNP) H.Otsu (RIKEN) Y.Matsuda (Tohoku Univ.) RIKEN H.Takeda K.Ozeki K.Yoneda K.Tanaka M.Takechi T.Ohnishi Tohoku Univ. T.Kobayashi Kyoto Univ. T.Murakami Miyazaki Univ. Y.Maeda Souel Univ. Y.Sato RCNP I.Tanihata O.H.Jin GSI S272 collaborators NIRS M.Kanazawa

3 Motivation Nuclear size and density distribution - Fundamental properties of nuclei - Inputs and/or guidelines to describe the nuclear reactions and structures Charge radius (Matter radius) Stable nuclei Muonic atom Unstable nuclei Isotope shift (Interaction cross section) Charge distribution Electron scattering Neutron distribution Proton elastic scattering Concerning the density distribution, experimetal data is rare!! Charge distribution / radius!charge radii are proportional to A 1/3!The diffuseness is independent of A, Neutron distribution!approximately equal to the proton distribution Matter radius! Matter radii have Isospin dependence.!skins arise from differences betwreen Sp and Sn.!Halo is caused by the loosely bound nucleon(s). Elastic scattering of Protons with RI beams

4 Stable nuclei Sakaguchi Group Polarized proton elastic scattering at 300MeV!They have succeeded in extracting neutron density distributions of Sn, Pb isotopes systematically. Sn Trial density + medium effect Search density + medium effect 116 Sn(x10 4 ) S.Terashima et al., Phys. Rev. C 77, (2008)! " 118 Sn(x10 2 ) 120 Sn(x1) 122 Sn(x10-2 ) 124 Sn(x10-4 ) # # Pb J.Zenihiro et al., Phys. Rev. C 82, (2010)!

5 Kinematics of ESPRI E p [MeV] H( C, p) C Ep=300 MeV/A Ex=30 MeV Large de/d!!! Ex=2.2 MeV g.s !lab. [deg.] It has been difficult to measure in a wide momentum transfer region. Experiments in the lower momentum transfer region (<1 fm -1 ) have been done so far. - RIKEN, GANIL,MSU : <100 MeV/A - GSI (He, Li isotope) : 700 MeV/A [mb/sr] dσ dω c.m Ep=300 MeV/A 9 9 H( C, p) C H( Ni, p) Ni θ c.m [degree]

6 Recoil Proton Spectrometer (RPS) NaI(Tl) E1 pδeup RDCup RPS p E7 p SHT p E8 RDCdown pδedown Beam X beam p E14 Y 1 m Solid H2 (SHT) RDC p"e E material Para H2 Ar+C2H6 Plastic NaI(Tl) effective area! 30 mm 436 x 436 mm x 440 mm x mm 2 thickness 1 mm 69.4 mm 2.53 / 3.09 mm 50.8 mm Resolution 500 "m TOF : 0.1 nsec 0.3 %(80 MeV)

7 Para Solid Hydrogen Target (p-sht) Ortho/Para H2 H2 molecular Nuclear spin of two protons Para H2 : singlet (S=0, J=0,2,4,...) Ortho H2 : Triplet (S=1, J=1,3,5,...) 300 K (Normal H2) para : ortho = 1:3 Thermal conductivity - W/m K 100 times larger than n-h2 metallic element Para H2 Normal H2 Thermal radiation Hole Temperature - K P.C.Souers, CRYOGENIC HYDROGEN DATA PERTINENT TO MAGNETIC FUSION ENERGY, Lawrence Livermore Laboratory Report UCRL (1979) Livermore California. 108 : R.W.Hill and B.Schneidmesser, Z.Physik. Chem. Neue Folge 16 (1958). 109 : R.G.Bohn and C.F.Mate, Phys. Rev. B 2 (1970) 2121.

8 Para Solid hydrogen target (p-sht) Para-H2 concentration Raman spectroscopy Collaboration with Dr. Koreeda. (Ultrafast Spectroscopy Group) Intensity [arbitrary unit] Para H2 99.9% Para Ortho S0(0) S0(1) Raman shift [cm ] #30 mm, 1 mm t

9 Experiments of ESPRI FY2006: 9 C 2008: 10,11 C Heavy Ion Medical Accelerator in Chiba (HIMAC) in National Institute of Radiological Science (NIRS) FY : 66,70 Ni Gesellshaft für Schwerionenforschung (GSI)

10 Experiments of 9,10,11 C A drastic growth of the density distribution with increase of the neutron number Yoshiko Kanada-En yo and Hisashi Horiuchi, Progress of Theoretical Physics Supplement, 142 (2001) 205

11 Experiments of 66,70 Ni Density Distribution and EOS The saturation density of nuclear matter is reflected to the density of nucleus. -> Saturation density of nuclear matter can be determined from density distributions. -> EOS of asymmetric matter can be studied from density distribution of neutron rich nuclei. 10 Binding Energy 0 density Den sity -20 Distance from center

12 Preliminary result Kinematics correlation (!lab. - Ep) Preliminary Preliminary Preliminary Recoil proton energy (MeV) E Tp [MeV] 9 C Recoil angle!lab. [degree] 10 C 11 C 12 C Recoil angle # lab. [deg.] Recoil angle # lab. [deg.] Recoil angle # lab. [deg.] Recoil angle # lab. [deg.] Preliminary Preliminary Preliminary 58 Ni 66 Ni 70 Ni Recoil angle # lab. [deg.] Recoil angle # lab. [deg.] Recoil angle # lab. [deg.]

13 Experiments of 9 C Differential cross section Density distributions & Radii [mb/sr] d" d# c.m C(H, 9 C) MeV/u! 9 C ESPRI data " 12 C Reference data RMF AMD1 AMD2! [fm -3 ] r [fm] RMF AMD1 AMD2 p r [fm] n Diffraction pattern is 10-2 smoother! !c.m.[degree] 9 C [fm] Preliminary rm rp rn "pn RMF 2.42* AMD1 2.42* AMD RMF: C.J.Horowiz et al., Comp. Nucl. Phys. 1, Chap. 7. AMD1: N.Furutachi et al., PTP 121(2009) 586. AMD2: Y.Kaneda-En yo et al., PTP 142(2001)647 * A.ozawa et al., NPA693(2001)32.

14 Summary! We proposed a project, Elastic Scattering of Protons with RI beams (ESPRI). - Size and density distributions of unstable nuclei - Related topics: asymmetric nuclear matter, weakly bound systems, modification of shell structure.! We have developed a Recoil Proton Spectrometer. - Thin and large solid hydrogen target - Extensive momentum transfer region: up to about 2 fm -1 - Excitation energy resolution : about 400 kev(rms)! We have measured following unstable nuclei so far: - 9,10,11 C - 66,70 Ni (We will obtain these density distributions in the near future.)