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Status of CNS GRAPE and γ-ray spectroscopy community in Japan

Status of CNS GRAPE and γ-ray spectroscopy community in Japan. Eiji Ideguchi CNS, University of Tokyo. Status of GRAPE. Members. CNS S. Shimoura (P) E. Ideguchi (L) S. Ota (PD) M. Niikura (D3) H. Miya(B4). CNS collaborators T. Fukuchi (RIKEN) M. Kurokawa (RIKEN) S. Michimasa (CNS)

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Status of CNS GRAPE and γ-ray spectroscopy community in Japan

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  1. Status of CNS GRAPE and γ-ray spectroscopy community in Japan Eiji Ideguchi CNS, University of Tokyo

  2. Status of GRAPE

  3. Members CNS S. Shimoura (P) E. Ideguchi (L) S. Ota (PD) M. Niikura (D3) H. Miya(B4) CNS collaborators T. Fukuchi (RIKEN) M. Kurokawa (RIKEN) S. Michimasa (CNS) H. Baba (RIKEN) CNS-UT-RIKEN-Rikkyo- -Kyoto... Collaboration

  4. GRAPE (Gamma-Ray detector Array with Position and Energy sensitivity) • 18x2 segmented Ge detectors • High Resolution • 2.5 keV intrinsic resolution for 1.3 MeV g • High Sensitivity • eW ~ 5 % for 1 MeV g • Position Sensitive • Resolution of Doppler Correction ~ 1 % Goal: 1mm position resolution for z-direction

  5. Reactions for the study of excited states • Direct Reactions (>30 MeV/u) • Heavy Nuclei: Strong Coulomb Field • Coulomb Excitation, Coulomb Dissociation • E1, E2, (M1) / Isovector • H, D, 4He [Liquid targets] • Inelastic Scattering • Isovector (H) / Isoscaler(H, D, 4He) • Spin-Flip (H, D) / Spin-Non-Flip (H, D,4He) • Charge Exchange • Fermi type (H) / Gamow-Teller type (H, D) • Nucleon Transfer • (a,t), (a,3He) Reaction • Knockout • Other (Be, C, …) • Knockout / Fragmentation • Spectroscopic Factor / States with various Spin • Fusion (& Multiple Coulex, Deep inelastic) (<20 MeV/u) • High Spin States Low multiplicity Liquid target High multiplicity

  6. Z-Position (~ q)  Drift length of electrons and holes ρ P-type, r~0.8x1010 cm-3 Z ⊿β=0.01: 50AMeV 12Be + 250mg/cm2 Be 50AMeV 32Mg + 70mg/cm2 Be 50AMeV 68Ni + 30mg/cm2 Be 200AMeV 68Ni + 200mg/cm2 Be

  7. Pulse Shape vs. Pos. (CR)2－(RC)4 shaping

  8. Block diagram Fast Amp Sum Amp Differentiation×2 TDC Pre Amp×9×2 Σ Ind. Zero cross disc. GRAPE S. Amp ADC Tsum – (Thit-Tsum) Segment Central segment Side segments Corner segments Sum M. Kurokawa et al., IEEE Trans. Nucl. Sci. , 50(2003)1309

  9. 4He(12Be,13Bγ) Doppler shift: 30% β~0.3 θ~140° 1.3% (FWHM) for 2.1MeV • Beam • 12Be 50AMeV • 200kcps • 55% purity • Target • Liquid Helium • 140mg/cm2 Charged particle detector Plastic scintillator ΔE, E, and position Gamma-ray detector Incident particle identification F2Pl Beam tracker Position and direction JPS 2007s

  10. Pulse Shape Analysis

  11. Doppler correction using PSA 4He(12Be, 12Beγ) After Doppler correction without PSA: take center of each detector As detector position and used fixedθ 2107keV FWHM～1.8% After Doppler correction with PSA FWHM～1.3% 12Be : 49MeV/A at center of target Target: Liq.He 143mg/cm2

  12. b=0.3 Dz(FWHM) ~ 3.4 mm

  13. Doppler Correction with Energy Degraded beam γ-ray energy spectrum before Doppler correction 70° 110° 90° 1220 801 X : 17 mm (s) Y : 8 mm (s) 230 511 404 2936 Energy (keV) 523 2-6 A MeV 1121 1548 50Ti

  14. Special setup • β –γ spectroscopy by using GRAPE + Clover Ge • R396n, T.K.Onishi et al. Life time measurement by Recoil Distance Method: GRAPE with BGO R400n, M.Suzuki et al. Spacer ε(1MeV) ～ 3% Au degrader 190mg/cm2 Au target 1.35g/cm2

  15. Downstream 885keV 32Mg Upstream Without BGO S/N ratio is improved Factor 2.5 With BGO

  16. Single hit Total Multiple hit Efficiency curve

  17. GRAPE at RIBF With BigRIPS +SHARAQ With RIPS With AVF (Stable beam) With BigRIPS+ZDS

  18. Gamma-ray spectroscopy community in Japan

  19. Low-energy beam facility in Japan Major places for γ-ray spectroscopy Osaka, RCNP AVF cyclotron 14 coaxial Ge array Isomer spectroscopy CYRIC, Tohoku University K130 AVF Cyclotron Hyperball-2 (6 Clover Ge and 14 coaxial Ge with BGO ACS) JAEA + KEK-TRIAC Tandem accelerator + booster GEMINI-Ⅱ (16 Coaxial Ge with BGO ACS) and other Ge’s Wako, Saitama CNS: GRAPE (18 segmented Ge) RIKEN: AVF cyclotron, Ring cyclotron, RIBF

  20. Japanese Gamma-ray Spectroscopy Association (JGSA) • Started from March 2007. • Purpose • Exchange information between research groups • Develop collaborative research activities • Experimentalists ⇔ Experimentalist ⇔ Theorist →　To define strategic target of this community (Detector, Physics, etc.) • Present Organizers • E. Ideguchi (CNS, Chair), N. Aoi (RIKEN), A. Odahara (Osaka), T. Koike (Tohoku), T. Nakatsukasa (RIKEN) • Web: http://www.cns.s.u-tokyo.ac.jp/gamma/ • Now it appears in Japanese language. • Internationalization will be discussed. • Mailing-list: gamma-ml@mail.cns.s.u-tokyo.ac.jp

  21. Numbers of registered members: 51 (as of Jan. 24, 2008) • Experimentalists: 42, Theorists: 9 • Affiliation: 3 Institutes and 10 Universities CNS, RIKEN, JAEA, KEK, Tokyo, Tohoku, Osaka, Kyoto, Kyushu, Niigata, Saitama, Chiba, Chiba Inst. Tech., Tokyo Univ. Sci. • Regular meetings • At biannual JPS meeting (Spring and Fall) • 1st Meeting: March 26, 2007 @ Tokyo Metropolitan Univ. • Kickoff meeting • 2nd Meeting: Sep. 22, 2007 @ Hokkaido Univ. • ExchangeInformation between groups (11 groups) • Discussion about future collaboration • 3rd Meeting: March 23, 2008 @ Kinki Univ. • Exchange Information between groups • Collaboration development

  22. CNS-RIKEN Joint International Symposium onFrontier of gamma-ray spectroscopy and Perspectives for Nuclear Structure Studies (gamma08) Date: April 3-5, 2008 Place: Nishina Hall in RIKEN Wako Campus Organizers: E. Ideguchi (CNS, Chair), N. Aoi (RIKEN), S. Michimasa (CNS), H. Scheit (RIKEN), A. Odahara (Osaka), T. Koike(Tohoku), T. Ishii(JAEA), T.Nakatsukasa(RIKEN),S. Shimoura(CNS), T. Motobayashi(RIKEN), T. Otsuka(CNS/Tokyo) Main topics to be discussed are:* Collectivities and shell effects in neutron/proton-rich nuclei * Shell structure and stability of very heavy nuclei * Exotic deformation / new collective motion at low and high spin * Single particle motion in isomeric states * Development of detectors and experimental methods Web: http://www.cns.s.u-tokyo.ac.jp/gamma08/→　Registration, abstract Deadlines* Deadline for abstract submission: February 15, 2008* Deadline for registration: March 21, 2008

  23. End

  24. Gamma-ray spectroscopy at RCNP in Osaka Univ. F１ SX2 SX1 D2 D1 Q4 Q3 Q5 Q2 Q6 Q1 Q7 F0 SX3 F２ east experimental hall EN course RCNP Osaka Univ. Maximum rigidity 3.2Tm Energy acceptance DE/E = 16 % Angular Acceptance Dq= 40 mrad Df = 28 mrad Path length 14.8m EN course　（RCNP RI beam line） T. Shimoda et al., NIM B70 (1992) 320. S. Mitsuoka et al., NIM A372 (1996) 489.

  25. Study for high-spin isomers using EN course ( RCNP RI beam line) • High-spin shape Isomers • innuclei withN=83, Z=60~68 • (1) prompt and delayed gg coincidence • 151Er116Sn(40Ar, 5n)151Er • (2) RI beam fusion reaction • primary reaction : 9Be(18O,17N)10B • secondary reaction:130Te(17N, 5n)142Pr • ( in this month) Ge detectors 14 ( co-axial Ge’s+ LEPS ) total efficiency : 1.9 % at 1.3 MeV collaboration with Dep. of Phys., Osaka Univ. RCNP, Osaka Univ. Dep. of Phys.. Tohoku Univ. SUNY oblate deformed high-spin shape isomer 2. Search and study for isomers in nuclei with N~51, Z~40 (1) recoil catcher method 86Kr beam + 13C target

  26. JAEA-Tokai Tandem & Superconducting Booster &TRIAC (Tokai Radioactive Ion Accelerator Complex) • VT=18MV ; new acceleration tubes; • ECR ion source on the terminal • Superconducting linac booster; • 40 quarter-wave resonators: V ~ 30MV • 18O (15MeV/u), 76Ge(10MeV/u), 127I( 6MeV/u), … • TRIAC: joint project between JAEA & KEK • Tandem( RI ; p+UC, 7Li+C,…) → ISOL • → Charge breeder → SCRFQ+IH-LINAC • 8Li (1.1MeV/u, 105/s),…. Oshima Gr. GEMINI-Ⅱ array Ishii Gr. 2 sites for γ-ray spectroscopy

  27. GEMINI-Ⅱarray • Detectors: • 16 Coaxial Ge • With BGO ACS • 3 LOAX • Auxiliary det. • LUNA: • Plastic and YAP Ce + • position ｓｅｎｓｉｔｉｖｅ PMT • SiBall (Kyushu Univ.) • Charged particle filter Si Ball Experiments: Coulex: 66,68Zn, 70,74,76Ge, 78Se, 84Kr, 98Mo In-beam: 43Sc,180Ir, 178Ir, 176Ir, 182Au, 172Re,etc   GEMINI-Ⅱ

  28. Experimental Setup - 18O + 248Cm experiment - • Beam : 18O(162MeV, VT=18MV), i=0.3pnA, [adjust with f2.5mm aperture] • Target: 248Cm (0.8mg/cm2) on Al(0.9mg/cm2) ; f3mm, 60mg, 45kBq • Detectors: 4 Si DE(75mm)-E placed at 40(+/- 11) degree[Si ELID wafer] • 6 Ge detectors; • eff = 12% @ 0.2 MeV, • 3%@1.3MeV Si DE-E Detectors

  29. a-g spectroscopy Gas-jet transport + Rotating wheel system 248Cm(18O,5n)261Rf 13 nb 248Cm(13C,4n)257No 1 mb Detection efficiency Si (a) : 80% Ge (g) : 30%

  30. Si ΔE E gate 248Cm→250Cm* Ex of 250Cm < Sn 18O 16O E-DE Plot & g-ray Spectra of 250Cm154 248Cm(18O,16O)250Cm; 2neutron-stripping Si E-DE PLOT Complete selection of g-rays in residual nuclei by measuring outgoing particles - Z, A, and kinetic energies -

  31. 井手口

  32. γ-ray imaging 5.8mm 6mm

  33. BGO Suppresor Preliminary

  34. 20cm 20cm 137Cs (662 keV) Pulse shape Sampling Automatic sampling system Flash-ADCs : Struck SIS3301 Rate : 105 MHz, Duration : 1 msec Input(10ch.) : Segment 1-9 + Sum Trigger : TFA + CFD 59 Positions 12 hours for 1 position ~ 1 Month 1. Measure1 (z-dependence) 2. Measure2 (x,y-dependence) 3. Combine Meas.1 & Meas.2 Pulse shape samples at 145 positions

  35. Measured Pulse Shapes Averaged pulse shape in each position 4 mm interval of whole volume (1/8 symmetry) Pulse shape samples at 145 positions Examples of position dependence Figure 1 Figure 2 Fig 1: x-position dependence Fig 2 : z-position dependence

  36. Expected Position Resolution (662 keV) ・Based on the measured pulse shapes, expected position resolution was calculated. Method : Calculate the signal difference of the all 2 position combinations Expected position resolutions position resolution physical distance between position i and j segment ID signal amplitude at the time t r.m.s of noise amplitude (a)z = 2 mm, (b) z = 10 mm, (c) z = 18mm, (d) y = 0 [ (a)(b)(c) xy-plane, (d) xz-plane ] Ref : K. Vetter et al., NIM A452 (2000) 278 Average ~ 1.30 mm, Worst ~ 3.13 mm@ P(28 mm, 8 mm, 6 mm)

  37. Administrative information • Contact person ＝ Susumu Shimoura (CNS) Eiji Ideguchi (CNS) ideguchi@cns.s.u-tokyo.ac.jp • Use of GRAPE • On collaboration base • In principle we will not lend the GRAPE alone • Man Power • At least 5 people including me are necessary to perform experiments using GRAPE. (e.g. Ideguchi, Fukuchi, Ota, Baba, Niikura, …) • For daily maintenance and R&D, at least one person fully in charge is necessary.

  38. In the experiment at RIPS, 7 days preparation time is necessary since we can not keep the setup • About 3 days for calibration and take down setup after the experiment • In the RIBF experiment, we require an arrangement of permanent setup of GRAPE • Arrangement of Liq N2 at RIBF is also very important (～250L/3days) • To build collaboration network for the use of GRAPE will be important if many people want γ-ray measurement with high resolution

  39. GRAPE at RIBF

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