Download or read book Shape and Structure of Neutron rich Nuclei from 252Cf Fission Fragments written by Jason Benjamin Snyder and published by . This book was released on 2014 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: The transition quadrupole moments, Qt, of rotational bands in the neutron-rich, even-mass 102-108Mo and 108-112Ru nuclei were measured with the Doppler-shift attenuation method. The nuclei were populated as fission fragments from 252Cf fission. The detector setup consisted of the Gammasphere spectrometer and the Hercules fast-plastic array. This allowed the measurement of asymmetric DSAM lineshapes at different Gammasphere detector angles with respect to the fission axis. The measurements typically covered the 6 to 16h spin range of the ground-state band and at least a strong transition in the [gamma] band. At moderate spin, the Qt moments are found to be reduced with respect to the values near the ground states, the latter being reported in the literature. An attempt has been made (by Afanasjev) to describe the data in the framework of cranked relativistic Hartree-Bogolyubov theory, and the results are reported in the present work as well as in a Physics Letters paper by Snyder et al. For 104Mo reliable predictions can be made. Here an oblate shape and a low-spin triaxial shape (deformation parameter [gamma]~-44°), predicted to be favored in other theoretical calculations, are ruled out by the data. There is some indication for a gradual change, at higher spin, from an initially prolate shape to a triaxial shape in 104Mo. The Qt data for 106Mo and 110,112Ru support this picture. The challenge of theory to describe the Qt data is addressed, which has to do with the very [gamma]-soft potential-energy surfaces. As a byproduct of the Qt analysis (which requires the determination of the intensities of the feeding transitions), the transition intensities of many weak high-spin or non-yrast states have been determined. These previously unknown intensity data are also reported. In the appendix, the results of an attenuation-coefficient analysis for [gamma]-ray angular distributions (due to recoil-in-vacuum) in heavy Ba isotopes are reported. These results are from a separate project, though from the same data set.
Download or read book Fission and Properties of Neutron rich Nuclei written by Joseph H. Hamilton and published by World Scientific. This book was released on 2003 with total page 859 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents more than 100 papers devoted to the understanding of fission processes and neutron-rich nuclei. All forms of fission, from spontaneous fission of 252Cf to high-energy fragmentation, are included. Together with studies on properties of neutron-rich nuclei and astrophysics, the book also features new experimental techniques, directions and the emerging new radioactive beam facilities.
Download or read book Fission And Properties Of Neutron rich Nuclei Proceedings Of The Third International Conference written by Joseph H Hamilton and published by World Scientific. This book was released on 2003-10-16 with total page 859 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents more than 100 papers devoted to the understanding of fission processes and neutron-rich nuclei. All forms of fission, from spontaneous fission of 252Cf to high-energy fragmentation, are included. Together with studies on properties of neutron-rich nuclei and astrophysics, the book also features new experimental techniques, directions and the emerging new radioactive beam facilities.
Download or read book Fission and Properties of Neutron rich Nuclei written by Joseph H. Hamilton and published by World Scientific Publishing Company Incorporated. This book was released on 2008 with total page 730 pages. Available in PDF, EPUB and Kindle. Book excerpt: "These proceedings are the fourth in the series of International Conferences covering fission and properties of neutron-rich nuclei, which are at the forefront of nuclear structure research. The time interval of 5 years between each conference allows for significant new results to be achieved. Recently, world leaders in theory and experiments in research and the development of new facilities for research presented their latest results in areas such as synthesis of superheavy elements, new facilities for and recent results with radioactive ion beams, structure of neutron-rich nuclei, nuclear fission process, fission yields and nuclear astrophysics. This book is a major source of the latest research in these areas and plans for the future. The conference brought together a unique group of over 100 speakers including the directors of the major nuclear laboratories in Canada, France, Germany, Japan, Russia and the US along with leading research scientists from around the world."--BOOK JACKET.
Download or read book Nuclear Structure Studies of Some Neutron Rich Nuclei Produced in 252Cf Spontaneous Fission written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Structure Studies of Neutron rich Nuclei Produced in the Spontaneous Fission of 252Cf written by Shaohua Liu and published by . This book was released on 2010 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Shapes from Spectroscopic Studies of Fission Fragments written by and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Partial level schemes for several neutron-rich Ba and Ce nuclei have been determined from the study of gamma-gamma coincidences in 252Cf fission fragments. The experiment was performed with the Argonne-Notre Dame gamma ray facility, which consisted of 7 Compton- suppressed Ge detectors, a low-energy photon spectrometer and an inner ball of fourteen hexagonal BGO detectors. Gamma-gamma coincidence events between the Ge detectors, which were accompanied by a gamma in BGO detectors, were accepted. The triple coincidence requirement eliminated most of the beta-decay background. Transitions in individual Ba and Ce nuclei were identified by gating on the known 2 .-->. O gamma rays. Level schemes deduced from these studies indicate interleaved negative and positive parity levels in 144Ba, 146Ba and 146Ce which are connected by fast E1 transitions. Both these features are signature of octupole deformation (reflection asymmetric shape) and are reproduced by recent theoretical calculations. 4 refs., 1 fig., 1 tab.
Download or read book Nuclear Shape and Structure in Neutron rich 110 111Tc written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The structure of Tc nuclei is extended to the moreneutron-rich regions based on measurements of prompt gamma rays from thespontaneous fission of 252Cf at Gammasphere. The level scheme of N=67neutron-rich (Z=43) 110Tc is established for the first time and that of111Tc is expanded. The ground-state band of 111Tc reaches theband-crossing region and the new observation of the weakly populatedalpha = -1/2 member of the band provides important information ofsignature splitting. The systematics of band crossings in the isotopicand isotonic chains and a CSM calculation suggest that the band crossingof the gs band of 111Tc is due to alignment of a pair of h11/2 neutrons. The best fit to signature splitting, branching ratios, and excitations ofthe ground-state band of 111Tc by RTRP model calculations result in ashape of epsilon2 = 0.32 and gamma = -26 deg. for this nucleus. Itstriaxiality is larger than that of 107Tc, to indicate increasingtriaxiality with increasing neutron number. The identification of theweakly-populated "K+2 satellite" band provides strong evidence for thelarge triaxiality of 111Tc. In 110Tc the four lowest-lying levelsobserved are very similar to those in 108Tc. At an excitation of 478.9keV above the lowest state observed, ten states of a delta I = 1 band areobserved. This band is very analogous to the delta I = 1 bands in106,108Tc, but it has greater signature splitting at higherspins.
Download or read book Nuclear Structure and Shapes from Prompt Gamma Ray Spectroscopy of Fission Products written by and published by . This book was released on 1996 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many nuclear shape phenomena are predicted to occur in neutron-rich nuclei. The best source for the production of these nuclides is the spontaneous fission which produces practically hundreds of nuclides with yields of greater than 0.1 % per decay. Measurements of coincident gamma rays with large Ge arrays have recently been made to obtain information on nuclear structures and shapes of these neutron- rich nuclei. Among the important results that have been obtained from such measurements are octupole correlations in Ba isotopes, triaxial shapes in Ru nuclei, two-phonon vibrations in 1°6Mo and level lifetimes and quadrupole moments in Nd isotopes and A=100 nuclei. These data have been used to test theoretical models.
Download or read book Spectroscopy of Neutron rich Nuclei Produced in the Spontaneous Fission of 252Cf written by Michael Wilhelm Simon and published by . This book was released on 1999 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Neutron Multiplicities in Spontaneous Fission and Nuclear Structure Studies written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: New insights into the fission process can be gained by better quantitative knowledge of how the energy released in fission is distributed between the kinetic energy of the two fragments, the excitation energy of the two fragments and the number of neutrons emitted. Studies of prompt gamma-rays emitted in spontaneous fission (SF) with large arrays of Compton suppressed Ge detector arrays are providing new quantitative answers to longstanding questions concerning fission as well as new insights into the structure of neutron-rich nuclei. For the first time the triple gamma coincidence technique was employed in spontaneous fission studies. Studies of SF of [sup 252]Cf and [sup 242]Pu have been carried out. These [gamma]-[gamma]-[gamma] data provide powerful ways to identify uniquely gamma rays from a particular nucleus in the very complex gamma-ray spectra given off by the over 100 different nuclei produced. The emphasis of this paper is on the first quantitative measurements of the multiplicities of the neutrons emitted in SF and the energy levels populated in the fragments. Indeed, in the break up into Mo-Ba pairs, we have identified for the first time fragments associated with from zero up to ten neutrons emitted and observed the excited energy states populated in these nuclei. The zero neutron emission pairs like [sup 104]Mo- [sup 148]Ba, [sup 106]Mo- [sup 146]Ba and [sup 104]Zr- [sup 148]Ce observed in this work are particularly interesting because they represent a type of cold fission or a new mode of cluster radioactivity as proposed by Greiner, Sandulescu and co-workers. These data provide new insights into the processes of cluster radioactivity and cold fission.
Download or read book High Spin States in Neutron Rich Nuclei from Spontaneous Fission written by and published by . This book was released on 1992 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: One fragment-[gamma]-[gamma] and three [gamma]-[gamma] coincidence measurements of the prompt [gamma]-rays from the fragments produced in the spontaneous fission (SF) of 252Cf and very recently of 242Pu were carried out with a 20 Ge detector ball at HHIRF. With our high statistics, [gamma]-[gamma]-[gamma] coincidences where the two gates are on transitions in the two partner fragments were extracted. Comparing the 252Cf and 242Pu data allowed unique placements of many transitions. New, higher spin states were observed in many nuclei, up to 16 in some of the heavy partners. Levels in several nuclei were observed for the full time. Studies of the fission process included measured relative branchings to the 1n to 6n channels. Much data remains to be analyzed. These data provide new insights into the changing structures at higher spins of many neutron-rich nuclei and the fission process.
Download or read book High Spin Studies of Neutron rich Nuclei Produced in the Spontaneous Fission Process of 252Cf written by Xueqian Zhang and published by . This book was released on 2001 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigations of Nuclear Structure written by and published by . This book was released on 2015 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proposal addresses studies of nuclear structure at low-energies and development of instrumentation for that purpose. The structure studies deal with features of neutron-rich nuclei with unexplored shapes (football- or pear-shaped nuclei). The regions of interest are: neutron rich nuclei like 132-138Sn, or 48-54Ca, and the Zr, Mo, and Ru isotopes. The tools used can be grouped as follows: either Gammasphere or Gretina multi-gamma detector arrays and auxiliary detectors (Microball, Neutron Shell, and the newly completed Phoswich Wall). The neutron-rich nuclei are accessed by radioactive-beam binary reactions or by 252Cf spontaneous fission. The experiments with heavy radioactive beams aim at exciting the beam nuclei by pick-up or transfer a neutron or a proton from a light target like 13C, 9Be, 11B or 14N .For these binary-reaction studies the Phoswich Wall detector system is essential. It is based on four multi-anode photomultiplier tubes on which CsI and thin fast-timing plastic scintillators are attached. Their signals are digitized with a high density microchip system.
Download or read book Properties of Neutron rich Nuclei Studied by Fission Product Nuclear Chemistry Review written by and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A review is given of the properties of neutron-rich nuclei studied by fission product nuclear chemistry and includes the techniques used in elemental isolation and current research on the structure of nuclei near 132Sn, particle emission, and coexisting structure in both neutron-poor and neutron-rich nuclei. 35 references. (JFP).
Download or read book Handbook of Nuclear Chemistry written by Attila Vértes and published by Springer Science & Business Media. This book was released on 2010-12-10 with total page 3693 pages. Available in PDF, EPUB and Kindle. Book excerpt: This revised and extended 6 volume handbook set is the most comprehensive and voluminous reference work of its kind in the field of nuclear chemistry. The Handbook set covers all of the chemical aspects of nuclear science starting from the physical basics and including such diverse areas as the chemistry of transactinides and exotic atoms as well as radioactive waste management and radiopharmaceutical chemistry relevant to nuclear medicine. The nuclear methods of the investigation of chemical structure also receive ample space and attention. The international team of authors consists of scores of world-renowned experts - nuclear chemists, radiopharmaceutical chemists and physicists - from Europe, USA, and Asia. The Handbook set is an invaluable reference for nuclear scientists, biologists, chemists, physicists, physicians practicing nuclear medicine, graduate students and teachers - virtually all who are involved in the chemical and radiopharmaceutical aspects of nuclear science. The Handbook set also provides further reading via the rich selection of references.
Download or read book Fission and Properties of Neutron rich Nuclei written by Joseph H. Hamilton and published by World Scientific. This book was released on 2003 with total page 859 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presenting more than 100 papers devoted to the understanding of fission processes and neutron-rich nuclei, this book covers all forms of fission, from spontaneous fission of 252Cf to high-energy fragmentation. Together with studies on properties of neutron-rich nuclei and astrophysics, the book also features new experimental techniques, directions and the emerging new radioactive beam facilities.
