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RESULTS: Singles Gamma Spectra  Five gamma energy transitions were  observed with energies739 keV, 822 keV, 712 keV 849 keV and 111 keV γ –γ Coincidence.

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Presentation on theme: "RESULTS: Singles Gamma Spectra  Five gamma energy transitions were  observed with energies739 keV, 822 keV, 712 keV 849 keV and 111 keV γ –γ Coincidence."— Presentation transcript:

1 RESULTS: Singles Gamma Spectra  Five gamma energy transitions were  observed with energies739 keV, 822 keV, 712 keV 849 keV and 111 keV γ –γ Coincidence Spectra Life time measurement  Shell Model calculation predicted the existence of (19/2 + ) isomer of a similar half life in 127Cd. A calculation using the E3 strength of the neighbouring 129 Sn isotone gives similar life time supporting the spin assignment.  The energy of 13/2 - state,obtained in Shell Model calculation is too high compared to the experiment value. Hence, a modification of the monopole interaction used in the calculation is required. EXPERIMENTAL TECHNIQUE :  In achromatic mode the fragments with same A/Q ratio are focused at the same position on the final focal plane RISING gamma array  15 Euroball cluster detectors with 7 crystals each  Photopeak efficiency ~ 15 % at 1 MeV EXP  48 Cd 79 is a neutron rich nucleus which has 3 neutrons and 2 protons less than the doubly magic 132 Sn. The latter nucleus is a benchmark for nuclear structure investigations.  Systematics of the Cd isotope chain shows evolution of neutron single particle energy levels. F.Naqvi, 1,2 M. Górska, 2 L. Cáceres, 2,3 A.Jungclaus, 3 M. Pfützner, 4 H. Grawe, 2 S. Pietri, 2 P. H Regan, 5 D. Rudolph, 6 Z. Podolyák, 5 K. Andgren, 7 T. Beck, 2 B. Bednarczyk, 2,8 J. Benlliure, 9 G. Benzoni, 10 A.M. Bruce, 11 E. Casarejos, 9 B. Cederwall, 7 F. Crespi, 10 P. Detistov, 12 Zs. Dombrádi, 13 P. Doornenbal, 2 H. Geissel, 2 J. Gerl, 2 J. Grębosz, 2,8 B. Hadinia, 7 M. Hellström, 6 R. Hoischen, 2,6 G. Ilie, 1 J.Jolie, 1 A. Khaplanov, 7 I. Kojouharov, 2 M. Kmiecik, 8 R. Kumar, 14 N. Kurz, 2 S. Lalkovski, 11,12 A. Maj, 8 S. Mandal, 15 V. Modamio, 3 F. Montes, 2 S. Myalski, 8 W. Prokopowicz, 2 P.Reiter, 1 H. Schaffner, 2 G. Simpson, 16 D.Sohler, 13 S.J. Steer, 5 S. Tashenov, 2 J. Walker, 3 H.J. Wollersheim 2 & O. Wieland 10  127 Cd was produced both in fragmentation of 136 Xe beam @ 750 MeV/u and in fission of 238 U beam @ 650 MeV/u.The intensities of the beams were ~ 7.4 X 10 8 ions/s and ~ 2.7 X 10 8 ions/s respectively  9 Be targets of thickness 1g/cm 2 and 4g/cm 2 were used for fission and fragmentation of 238 U and 136 Xe beams respectively  The observed neutron single particle evolution helps in determining the monopole interaction used in SM calculation.  The comparison of theoretical predictions and experimental results provides a means for understanding the structure of neutron rich isotopes below 132 Sn and possible on-set of collectivity. 1 Institut für Kernphysik, Universität zu Köln, D-50937 Köln, Germany. 2 Gesellschaft für Schwerionenforschung (GSI), D-64291 Darmstadt, Germany 3 Departamento de Física Teórica, Universidad Autónoma de Madrid, E-28049 Madrid, Spain. 4 IEP, Warsaw University, PL-00681 Warsaw, Poland. 5 Department of Physics, University of Surrey, Guildford, GU2 7XH, UK. 6 Department of Physics, Lund University, S-22100 Lund, Sweden. 7 KTH Stockholm, S-10691 Stockholm, Sweden.. 8 The Henryk Niewodniczański Institute of Nuclear Physics, PL-31342 Kraków, Poland. 9 Universidad de Santiago de Compostela, E-175706 Santiago de Compostela, Spain. 10 INFN, Universitádegli Studi di Milano and INFN Seizone di Milano,I-20133 Milano, Italy. 11 School of Engineering, University of Brighton, Brighton, BN2 4GJ, UK. 12 Faculty of Physics, University of Sofia, BG-1164 Sofia, Bulgaria. 13 Institute National Polytechnique de Grenoble, F – 98026 Grenoble Cedex, France 14 Inter University Accelerator Centre, New Delhi, India. 15 University of Delhi, New Delhi, India. 16 Institut Laue-Langevin, F-38042 Grenoble, France. FRAGMENT SEPARATOR Z Measurement  Energy loss in two MUlti Sampling Ionisation Chambers at S4 A/Q Measurement  Time of flight measurement between scintillators Sc21 at S2 and Sc42 at S4 Bρ-ΔE-Bρ method (Achromatic Mode) SM  The decay of yrast (19/2 + ) isomer was observed in 127 Cd.  Based on the measured half-life T 1/2 = 17.5(3)µs, primary decay transitions were assigned to be an E3 of 849 keV and M2/E3 of 739 keV. TOF : βγ DIPOLE : Bρ 127 Identification plot Energy and lifetime information from the gamma array  Gamma coincidence spectra gated on 739 keV  Time distribution obtained by summing the gates at 712 keV, 739 keV, 821 keV, and 849 keV on the energy vs time matrix  A maximum likelihood fit gives a half life of T 1/2 = 17.5(3) µs 


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