Search results for "Ph. D."
showing 10 items of 180 documents
Precision measurements of proton emission from the ground states ofTa156andRe160
2011
The decays of the $\ensuremath{\pi}{d}_{3/2}$ ground states of $^{156}\mathrm{Ta}$ and $^{160}\mathrm{Re}$ have been studied in detail using the GREAT spectrometer. More than 7000 $^{160}\mathrm{Re}$ nuclei were produced in reactions of 290- and 300-MeV $^{58}\mathrm{Ni}$ ions with an isotopically enriched $^{106}\mathrm{Cd}$ target and separated in flight using the RITU separator. The proton and $\ensuremath{\alpha}$ decays of the $\ensuremath{\pi}{d}_{3/2}$ level were confirmed and the half-life and branching ratios of this state were determined with improved precision to be ${t}_{1/2}=611\ifmmode\pm\else\textpm\fi{}7$ $\ensuremath{\mu}$s and ${b}_{\mathrm{p}}=89\ifmmode\pm\else\textpm\fi…
In-beam and decay spectroscopy of very neutron deficient iridium nuclei
2005
Iridium nuclei at and beyond the proton drip line have been studied via fusion evaporation reactions. A reaction of 92Mo(78Kr, p2n) at a beam energy of 360 MeV and target thickness 500 µg cm−2 was employed to study 167,167mIr. A reaction of 112Sn(58Ni, p2n) at a beam energy of 266 MeV and target thickness 500 µg cm−2 was used to study 169,169mIr. The experiments were performed at the University of Jyvaskyla utilizing the RITU separator in conjunction with the focal plane GREAT spectrometer and the JUROGAM Ge array at the target position. Excited states feeding both the ground state and isomeric state in 169Ir, excited states feeding the ground state of 167Ir and the ground state alpha decay…
The 48Ca+181Ta reaction: Cross section studies and investigation of neutron-deficient 86 ≤ Z ≤ 93 isotopes
2019
© 2019 Fusion-evaporation reactions with the doubly magic projectile 48 Ca were used to access neutron-deficient nuclei around neptunium at the velocity filter SHIP, and investigated using the COMPASS decay spectroscopy station. With the use of digital electronics, several isotopes produced via neutron, proton, and α evaporation channels were identified by establishing correlated α-decay chains with short-lived sub-μs members. Data are given on decay chains stemming from 225,226 Np, 225 U, and 222,223 Pa. New information on the isotopes 225,226 Np and 222 Pa was obtained. Production cross sections of nuclei in the region using a variety of projectiles are discussed. The measured production …
Identification of low-lying proton-based intruder states in189–193Pb
2002
Low-lying proton-based intruder states have been observed in the odd-mass isotopes Pb-189,Pb-191,Pb-193 in experiments at the RITU gas-filled recoil separator. The identification has been performed ...
α-decay spectroscopy of deformed nuclei reexamined
2008
We perform an extensive analysis of $\ensuremath{\alpha}$-decays to ${2}^{+}$ and ${4}^{+}$ states in deformed even-even nuclei by using the stationary coupled channels approach. Collective excitations are described within the rigid rotor model. The $\ensuremath{\alpha}$-nucleus interaction is given by a double folding procedure with M3Y plus Coulomb nucleon-nucleon forces. We use a repulsive potential with one independent parameter in order to localize the $\ensuremath{\alpha}$-particle on the nuclear surface and to fit the experimental $Q$-value. The decaying state is identified with the first resonance inside the resulting pocket-like potential, as suggested by microscopic calculations. …
Conversion electron and beta decay spectroscopy at SHIP
2004
Abstract Novel methods for internal conversion electron and β -decay spectroscopy at the focal plane of a recoil separator are discussed. As an example the experimental data collected at the focal plane of the velocity filter SHIP (GSI, Darmstadt) are presented and compared with the results of the GEANT Monte Carlo simulations. It is shown that the simultaneous detection of conversion electrons, γ -rays and X-rays is possible, which significantly broadens the range of applications of this and similar systems.
α-decay properties ofPb181
1996
The isotope {sup 181}Pb was produced in {sup 92}Mo bombardments of {sup 90}Zr and, together with other reaction products, was passed through a recoil mass separator and implanted in a double-sided silicon strip detector for {alpha}-particle assay. The half-life and energy of the main {sup 181}Pb {alpha} transition were determined to be 45 (20) ms and 7065 (20) keV, respectively. This {sup 181}Pb {ital E}{sub {alpha}} agrees with one previously measured value [7044 (15) keV], but not with the one [7211 (10) keV] used as input to the 1993 Atomic Mass Evaluation. The 6180-keV {alpha} transition assigned to {sup 181}Tl by Bolshakov {ital et} {ital al}. was observed, but the 6566-keV {alpha} par…
A dedicated decay-spectroscopy station for the collinear resonance ionization experiment at ISOLDE
2013
A newdecay-spectroscopystation(DSS)has been developed to be coupled to the collinear resonance ionization spectroscopy (CRIS) beam line at CERN-ISOLDE. The system uses a rotatable wheel with ten 20 mg=cm2 carbon foils as beam implantation sites for the efficient measurement of charged decay products. Silicon detectors are placed on either side of the carbon foil in an optimal geometry to cover a large solid angle for detecting these charged particles. In addition to the silicon detectors at the on-beam axis position, a second pair of off-beam axis detectors are placed at the wheel position 108 deg. away, allowing longer-lived species to be studied. Up to three high purity germanium detector…
Decay properties of265Sg(Z=106)and266Sg(Z=106)
1998
The presently known most neutron-rich isotopes of element 106 (seaborgium, Sg), {sup 265}Sg and {sup 266}Sg, were produced in the fusion reaction {sup 22}Ne+{sup 248}Cm at beam energies of 121 and 123 MeV. Using the On-Line Gas chemistry Apparatus OLGA, a continuous separation of Sg was achieved within a few seconds. Final products were assayed by {alpha}-particle and spontaneous fission (SF) spectrometry. {sup 265}Sg and {sup 266}Sg were identified by observing time correlated {alpha}-{alpha}-({alpha}) and {alpha}-SF decay chains. A total of 13 correlated decay chains of {sup 265}Sg (with an estimated number of 2.8 random correlations) and 3 decay chains of {sup 266}Sg (0.6 random correlat…
First observation of excited states inHg17595
2009
Excited states of the neutron-deficient nucleus Hg-175, populated using fusion-evaporation reactions, are reported for the first time. The spin and parity of the ground state has been determined to ...