ISOMER SPECTROSCOPY OF 127 Cd

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ISOMER SPECTROSCOPY OF 127 Cd. 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 - PowerPoint PPT Presentation

Text of ISOMER SPECTROSCOPY OF 127 Cd

  • RESULTS:

    Singles Gamma Spectra Five gamma energy transitions were observed with energies739 keV, 822 keV , 712 keV 849 keV and 111 keV

    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 129Sn 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 array15 Euroball cluster detectors with 7 crystals eachPhotopeak efficiency ~ 15 % at 1 MeV

    EXP

    48Cd79 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. Grska,2 L. Cceres,2,3 A.Jungclaus,3 M. Pftzner,4 H. Grawe,2 S. Pietri,2 P. H Regan,5 D. Rudolph,6 Z. Podolyk,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. Dombrdi,13 P. Doornenbal,2 H. Geissel,2 J. Gerl,2 J. Grbosz,2,8 B. Hadinia,7 M. Hellstrm,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. Wollersheim2 & O. Wieland10

    127 Cd was produced both in fragmentation of 136 Xe beam @ 750 MeV/u and in fission of 238U beam @ 650 MeV/u .The intensities of the beams were ~ 7.4 X 108 ions/s and ~ 2.7 X 108 ions/s respectively

    9Be targets of thickness 1g/cm2 and 4g/cm2 were used for fission and fragmentation of 238U and 136Xe 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 132Sn and possible on-set of collectivity.

    1Institut fr Kernphysik, Universitt zu Kln, D-50937 Kln, Germany. 2Gesellschaft fr Schwerionenforschung (GSI), D-64291 Darmstadt, Germany3Departamento de Fsica Terica, Universidad Autnoma de Madrid, E-28049 Madrid, Spain.4IEP, Warsaw University, PL-00681 Warsaw, Poland.5Department of Physics, University of Surrey, Guildford, GU2 7XH, UK.6Department of Physics, Lund University, S-22100 Lund, Sweden.7KTH Stockholm, S-10691 Stockholm, Sweden.. 8The Henryk Niewodniczaski Institute of Nuclear Physics, PL-31342 Krakw, Poland.

    9Universidad de Santiago de Compostela, E-175706 Santiago de Compostela, Spain. 10INFN, Universitdegli Studi di Milano and INFN Seizone di Milano,I-20133 Milano, Italy.11School of Engineering, University of Brighton, Brighton, BN2 4GJ, UK. 12Faculty of Physics, University of Sofia, BG-1164 Sofia, Bulgaria.13Institute National Polytechnique de Grenoble , F 98026 Grenoble Cedex , France14Inter University Accelerator Centre, New Delhi, India. 15University of Delhi, New Delhi, India. 16Institut Laue-Langevin, F-38042 Grenoble, France.FRAGMENT SEPARATORZ MeasurementEnergy loss in two MUlti Sampling Ionisation Chambers at S4A/Q Measurement Time of flight measurement between scintillators Sc21 at S2 and Sc42 at S4 B-E-B method (Achromatic Mode) SM

    The decay of yrast (19/2+) isomer was observed in 127Cd.

    Based on the measured half-life T1/2 = 17.5(3)s , primary decay transitions were assigned to be an E3 of 849 keV and M2/E3 of 739 keV.

    TOF : DIPOLE : B127 Identification plotEnergy 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 T1/2 = 17.5(3) s

    Chart1

    2313.110652.2376552.23765

    2371.5571352.0067652.00676

    2344.8339851.550551.5505

    1992.7855248.0233448.02334

    1809.2054445.8981545.89815

    1707.2347444.5146944.51469

    1505.4630142.2342942.23429

    1387.1647940.5401440.54014

    1265.0344239.0584339.05843

    1106.0219736.9368436.93684

    1022.5488935.5404435.54044

    963.9680834.3882434.38824

    845.3740832.7317532.73175

    790.8049331.7537231.75372

    645.6116329.4987829.49878

    649.280729.1649329.16493

    636.373629.0537329.05373

    472.14726.0491226.04912

    T1/2 = 17.5(3)s

    Time [ns]

    Counts/ 2500[ns]

    Life Time Analysis

    Sheet1

    25002313.110652.23765

    50002371.5571352.00676

    75002344.8339851.5505

    100001992.7855248.02334

    125001809.2054445.89815

    150001707.2347444.51469

    175001505.4630142.23429

    200001387.1647940.54014

    225001265.0344239.05843

    250001106.0219736.93684

    275001022.5488935.54044

    30000963.9680834.38824

    32500845.3740832.73175

    35000790.8049331.75372

    37500645.6116329.49878

    40000649.280729.16493

    42500636.373629.05373

    45000472.14726.04912

    Sheet1

    052.2376552.23765

    052.0067652.00676

    051.550551.5505

    048.0233448.02334

    045.8981545.89815

    044.5146944.51469

    042.2342942.23429

    040.5401440.54014

    039.0584339.05843

    036.9368436.93684

    035.5404435.54044

    034.3882434.38824

    032.7317532.73175

    031.7537231.75372

    029.4987829.49878

    029.1649329.16493

    029.0537329.05373

    026.0491226.04912

    T1/2 = 17.5(3)s

    Time [ns]

    Counts/ 2500[ns]

    Life Time Analysis

    Sheet3

    *