The medical student

The Medical Student was published from 1888-1921 by the students of Boston University School of Medicine

Beta decay of 71,73Co; probing single particle states approaching doubly magic 78Ni

Low-energy excited states in 71,73Ni populated via the {\beta} decay of 71,73Co were investigated in an experiment performed at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU). Detailed analysis led to the construction of level schemes of 71,73Ni, which are interpreted using systematics and analyzed using shell model calculations. The 5/2- states attributed to the the f5/2 orbital and positive parity 5/2+ and 7/2+ states from the g9/2 orbital have been identified in both 71,73Ni. In 71Ni the location of a 1/2- {\beta}-decaying isomer is proposed and limits are suggested as to the location of the isomer in 73Ni. The location of positive parity cluster states are also identified in 71,73Ni. Beta-delayed neutron branching ratios obtained from this data are given for both 71,73Co.Comment: Accepted for publication in PR

The Single-Particle Structure of Neutron-Rich Nuclei of Astrophysical Interest at the Ornl Hribf

The rapid nuetron-capture process (r process) produces roughly half of the elements heavier than iron. The path and abundances produced are uncertain, however, because of the lack of nuclear strucure information on important neutron-rich nuclei. We are studying nuclei on or near the r-process path via single-nucleon transfer reactions on neutron-rich radioactive beams at ORNL's Holifield Radioactive Ion Beam Facility (HRIBF). Owing to the difficulties in studying these reactions in inverse kinematics, a variety of experimental approaches are being developed. We present the experimental methods and initial results.Comment: Proceedings of the Third International Conference on Fission and Properties of Neutron-Rich Nucle

β -decay study of Kr 94

β decay of neutron-rich nuclide Kr94 was reinvestigated by means of a high resolution on-line mass separator and β-γ spectroscopy. In total 22 γ-ray transitions were assigned to the decay of Kr94, and a new isomeric state was identified. The new information allows us to build detailed levels systematics in a chain of odd-odd rubidium isotopes and draw conclusions on nuclear structure for some of the observed states. The discussed level structure affects the evolution of β-decay half-lives for neutron-rich selenium, krypton, and strontium isotopes

β-decay studies of the transitional nucleus Cu75 and the structure of Zn75

The β decay of Cu75 [t1/2=1.222(8)s] to levels in Zn75 was studied at the Holifield Radioactive Ion Beam Facility of Oak Ridge National Laboratory. The γγ and βγ data were collected at the Low-energy Radioactive Ion Beam Spectroscopy Station using the high-resolution isobar separator to obtain a purified Cu75 beam with a rate of over 2000 ions per second. The excited states in Zn75 have been identified for the first time. A total of 120 γ-ray transitions were placed in a level scheme containing 59 levels including two states above the neutron separation energy and a previously unknown 1/2- isomeric state at 127 keV. Spins and parities of several states were deduced and interpreted based on the observed β feeding and γ-decay pattern. © 2011 American Physical Society

First observation of the drip line nucleus \u3csup\u3e140\u3c/sup\u3eDy: Identification of a 7 μs K isomer populating the ground state band

A new 7 μs isomer in the drip line nucleus 140Dy was selected from the products of the 54Fe (315 MeV) + 92Mo reaction by a recoil mass spectrometer and studied with recoil-delayed γ-γ coincidences. Five cascading γ transitions were interpreted as the decay of an Iπ = 8- {ν9/2-[514]⊗ ν7/2+[404]} Kisomer (T 1/2 = 7.0(5) μs) via the ground-state band. The probability of proton emission from 141Ho to the 0+ ground state and to the 2+ excited state in 140Dy is discussed

Systematics of low energy collective states in neutron-rich Cd isotopes

It has been shown that there are significant deviations from the expected U(5) dynamical symmetry for 110,112,114,116Cd. However, there is very significant mixing with intruder states in this region. In this paper, we investigated states in the heavier 120,124,126Cd populated via beta decay. These nuclei exhibit similar patterns to the lighter Cd isotopes even though the intruder states are much higher in energy. © Published under licence by IOP Publishing Ltd

β -delayed neutron emission from Ga 85

Decay of Ga85 was studied by means of β-neutron-γ spectroscopy. A pure beam of Ga85 was produced at the Holifield Radioactive Ion Beam Facility using a resonance ionization laser ion source and a high-resolution electromagnetic separator. The β-delayed neutron emission probability was measured for the first time, yielding 70(5)%. An upper limit of 0.1% for β-delayed two-neutron emission was also experimentally established for the first time. A detailed decay scheme including absolute γ-ray intensities was obtained. Results are compared with theoretical β-delayed emission models