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cross-section (a.u.) Cross Section from 0 degree telescope 0.025 0.02 0.015 0.01 0.005 0 hist_sigma Entries 128 Mean 2230 RMS 117.4 2050 2100 2150 2200 2250 2300 2350 2400 2450 Ecm (keV) Figure 3. Breit-Wigner fit for the peak at � �� =2249keV., corresponding to the excited state � � =7687keV, �� =� � . [5] cross-section (a.u.) Cross Section from 0 degree telescope 0.01 0.008 0.006 0.004 0.002 0 hist_sigma Entries 128 Mean 3120 RMS 84.31 2950 3000 3050 3100 3150 3200 3250 Ecm (keV) Figure 4. Breit-Wigner fit for the peak at �� =3100keV., corresponding to the excited state �� =8563keV, � � =� � . [8] References [1] J. Chen et al., CNS Annual Reprot (2006) 5. [2] D. W. Bardayan et al., Phys. Rev. C 65 (2002) 032801. [3] J. A. Caggiano et al., Phys. Rev. C 65 (2002) 055801. [4] Y. Parpottas et al., Phys. Rev. C 70 (2004) 065805. [5] D. W. Bardayan et al., Phys. Rev. C 74 (2006) 045804. [6] S. Kubono, Nucl. Phys. A 693 (2001) 221-248. [7] A. H. Hernández et al., NMB 143 (1998) 569-574 [8] J. C. Thomas et al., Eur. Phys. J.A 21 (2004) 419-435. [9] A. M. Lane, and R. G. Thomas, Rev. Mod. Phys. 30 (1958) 257 20
High-spin States in �� Ti M. Niikura, E. Ideguchi, N. Aoi a , H. Baba a , T. Fukuchi a , Y. Ichikawa a , H. Iwasaki b , T. Kubo a , M. Kurokawa a , M. Liu c , S. Michimasa, T. Ohnishi a , T. K. Onishi b , S. Ota, S. Shimoura, H. Suzuki a , D. Suzuki b , Y. Wakabayashi, K. Yoshida a and Y. Zheng c Center for Nuclear Study, Graduate School of Science, University of Tokyo a RIKEN (The Institute of Physical and Chemical Research) b Department of Physics, Graduate School of Science, University of Tokyo c Institute of Modern Physics, Chinese Academy of Sciences Shell structure in the neutron-rich �� -shell � nuclei has recently become the focus of much � theoretical and �� experimental effort. As the neutron number increases, � � there � may � be � rearrangements of the single-particle orbits and �� develop- � ments �� of new � sub-shell closures. Emergence of a sub-shell �� gap at reported �� in Ca, Ti and Cr is �� one � of �� the good examples [1, 2, �� 3]. Since nuclei � with certain amount of � � �� spins need to promote nucleons across the major shell gap in order to gain � the large angular momentum � and single particle � states could be appeared in those excited states, spectroscopic studies at high spin may serve as a � sensitive � � probe � of � the � location � of � single � particle orbits. In this report, the ��¨�� in-beam �� -ray �� ¨�� spectroscopy in Ti �� via the secondary �� fusion �� ¥�� reaction [4], , are described. The experiment was �� performed ��¨�� at � the RIKEN Projectile- � � � �� fragment � Separator (RIPS) facility in RIKEN [5]. A sec- �� ondary beam of Ar �� was �� produced � by �� projectile � fragmentation �� of �� Ca �� at � the �� energy of 64 �� MeV/nucleon and � its energy was lowered using aluminum energy degraders placed � at � the � first and second focal planes (F1, F2) of RIPS. The intensity and energy of the low-energy radioactive isotope (RI) beam � �� were particle per � second � and about 4.0 MeV/nucleon, respectively. The secondary beam bombarded a m-thick 10-� Be � target placed at the final focal � plane (F3) � to induce secondary fusion reactions, �� . �� Gamma rays emitted from evaporation residues were detected by the CNS Gamma-Ray detector Array with Po- Figure 1. The energy of incident and outgoing particles (a) and sition and Energy sensitivity (CNS-GRAPE) [6] together timing spectrum of the germanium detectors (b). with two clover and one coaxial germanium detectors. These -ray detectors were placed around the secondary The timing at the target � was deduced by extrapolation from target to cover 120� the angular range between and timing on F2pl and F3PPACs. Figure 1(a) shows the en- 30� relative to the beam direction. In order to correct the ergy of the incident and outgoing particles. By gating on Doppler shift of the rays emitted from moving particles the fusion event region, backgrounds � due to accidental co- ), (� �� pulse-shape analysis was performed for the outincidences are reduced as shown in Fig. 1(b) where timing put from CNS-GRAPE to determine the interaction points spectra of the germanium detectors with and w/o the gate of the rays in the detector [7]. The energy � resolution of are presented. 15 keV (FWHM) for 1.5-MeV rays was obtained � -� after the In order to � construct the level scheme, coincidence Doppler correction. analysis was carried out for Ti. Prior �� to the present inves- Event identification was performed based � on the veloctigation, four transitions at 1437, 907, 410 and 892 keV ity difference between the beam and the fusion products. corresponding to 7/2 The velocity of incident beam was deduced by time of flight (TOF) between plastic scintillator at F2 (F2pl) and parallelplate avalanche counters at F3 (F3PPACs), and that of the outgoing particles was measured by TOF between the secondary target and PPAC placed downstream of the target. �� 3/2, 11/2 �� 7/2 � , 15/2 �� 11/2 � and (13/2, 17/2) � 15/2 � , respectively, were reported by S. E. Arnell et al. [8]. Figure 2(a) shows � summed -ray spectrum gated on � the known 907- and 892-keV lines. Three new peaks at 667, 761 and � 837 keV belonging to Ti were observed and other peaks are mainly contami- �� 21
Page 1 and 2: ISSN 1343-2230 CNS-REP-80 August, 2
Page 3: Annual Report 2007 Center for Nucle
Page 6 and 7: Collider (LHC) at CERN. The group h
Page 8 and 9: Study of High-Spin States in A� 3
Page 10 and 11: Appendices Symposium, Workshop, Sem
Page 13 and 14: Searching for resonances in the �
Page 15 and 16: Elastic Scattering and Breakup of
Page 17 and 18: Production of the spin-polarized
Page 19 and 20: The � � F+p process and the Nov
Page 21 and 22: �� S Beam Production with CR
Page 23 and 24: Development of � Cr secondary bea
Page 25 and 26: Low-lying � -wave resonance of
Page 27 and 28: Cluster states in � Y. Sasamoto,
Page 29 and 30: Proton Inelastic Scattering Study o
Page 31: Study of Astrophysically Important
Page 35 and 36: Study of High-Spin States in A� 3
Page 37 and 38: Search for Superdeformed Band in A
Page 39 and 40: Analyzing Power Measurement for the
Page 41 and 42: � � B+p Reaction at Astrophysic
Page 43: Experimental Nuclear Physics: PHENI
Page 46 and 47: The �� yield suppressi
Page 48 and 49: Figure 1. Schematics of the produce
Page 50 and 51: eterizations of the single electron
Page 52 and 53: ground) was fitted to the reconstru
Page 54 and 55: cle identification. Conditional pro
Page 56 and 57: upper layer to monitor the state of
Page 58 and 59: as ��
Page 60 and 61: Figure 3. Electron spectra from cha
Page 62 and 63: 4. Analysis Test beam data was anal
Page 64 and 65: The following function is used for
Page 67 and 68: 1. Introduction Development of a re
Page 69 and 70: SHARAQ Project - Progress in FY2007
Page 71 and 72: References [1] T. Uesaka et al., Nu
Page 73 and 74: supplies were sufficiently stable t
Page 75 and 76: symmetric electric fields in the vi
Page 77 and 78: (a) (b) Figure 4. (a) The photo of
Page 79 and 80: experiment. 3. Performance of the p
Page 81 and 82: Table 1. Specifications of core mon
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Figure 3. Beam envelope of the anal
Page 85:
Figure 3. Bunching effect near the
Page 89 and 90:
Electromagnetic Transitions in Exot
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∆ (MeV) 3 2.5 2 1.5 1 BCS 0.5 w/
Page 95 and 96:
The Sixth CNS International Summer
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about the experimental nuclear phys
Page 101 and 102:
A. Workshop Workshop, Seminar, and
Page 103 and 104:
CNS Reports #70 “Onset of ��
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13. Y.K. Kwon, C.S. Lee and S. Kubo
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5. S. Michimasa, S. Shimoura, H. Iw
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30. T. Isobe (for the PHENIX Collab
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17. T. Uesaka, S. Shimoura, H. Saka
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39. T. Uesaka (Oral), “Spin Asymm
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B. JPS Meetings 1. S. Michimasa, Y.
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Director Personnel OTSUKA, Takaharu
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Committees Council YAMAMOTO, Masayu
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