Search results for "nuclear reaction"
showing 10 items of 449 documents
Half-life measurements for neutron-rich Tc, Ru, Rh, and Pd isotopes. Identification of the new isotopesTc111,Ru113, andRh113
1988
The decays of three new neutron-rich nuclides $^{111}\mathrm{Tc}$, $^{113}\mathrm{Ru}$, and $^{113}\mathrm{Rh}$ have been observed at an on-line isotope separator facility. In addition, the beta decays of several other n-rich isotopes with Ag100 have been studied for the first time. The new half-lives reported in this work include: $^{111}\mathrm{Tc}$ [${T}_{1/2}$=0.30(3) s], $^{111}\mathrm{Ru}$ [2.12(7) s], $^{112}\mathrm{Ru}$ [1.75(7) s], $^{113}\mathrm{Ru}$ [0.80(10) s], $^{113}\mathrm{Rh}$ [2.72(22) s], and $^{118}\mathrm{Pd}$ [2.24(17) s]. In general, these results support the microscopic theoretical half-life predictions below Z=50.
Excitation and decay of two-phonon giant dipole resonances
1999
Abstract In heavy ion collisions at near relativistic energies, electromagnetic excitation of the double giant dipole resonance occurs with large cross sections. We summarize the presently available experimental data and discuss related theoretical efforts. Emphasis is paid to the question of anharmonicities and to the damping of the two-phonon states.
Discovery of 157W and 161Os
2010
The nuclides W-157 and Os-161 have been discovered ill reactions of Ni-58 ion beams with a Cd-106 target. The Os-161 alpha-decay energy and half-life were 6890 +/- 12 keV and 640 +/- 60 mu s. The d ...
First superheavy element experiments at the GSI recoil separator TASCA: The production and decay of element 114 in thePu244(Ca48,3-4n) reaction
2011
Experiments with the new recoil separator, Transactinide Separator and Chemistry Apparatus (TASCA), at the GSI were performed by using beams of Ca-48 to irradiate targets of Pb206-208, which led to the production of No252-254 isotopes. These studies allowed for evaluation of the performance of TASCA when coupled to a new detector and electronics system. By following these studies, the isotopes of element 114 ((288-291)114) were produced in irradiations of Pu-244 targets with Ca-48 beams at compound nucleus excitation energies around 41.7 and 37.5 MeV, demonstrating TASCA's ability to perform experiments with picobarn-level cross sections. A total of 15 decay chains were observed and were as…
Electromagnetic production of polarization in hypernuclei.
1991
The formation of polarized hypernuclei through kaon photoproduction is investigated in a distorted-wave impulse approximation approach. The polarization depends strongly on the model used to describe the elementary process. For one particular model and certain well populated states the amount of polarization may reach up to 50%. We present cross sections and polarizations for kaon photoproducton on $^{16}\mathrm{O}$, $^{28}\mathrm{Si}$, $^{56}\mathrm{Fe}$, and $^{89}\mathrm{Y}$ and demonstrate the sensitivity of polarization to distortion and nonlocal effects. More information on the elementary process is needed before the feasibility of such measurements can be established.
Radioactive beams at GSI
2001
Abstract After a brief introduction the production of relativistic beams of exotic nuclei will be discussed and some characteristic examples from the ongoing GSI nuclear structure research programme are presented, such as: nuclear reactions with exotic beams to explore nuclear skins, the structure of halo nuclei, and direct mass measurements in a storage ring. Heavy-element research will be addressed briefly. A possible next generation exotic beam facility at GSI will be outlined.
Experimental study ofβ-delayed proton decay ofAl23for nucleosynthesis in novae
2011
The $\ensuremath{\beta}$-delayed $\ensuremath{\gamma}$ and proton decay of $^{23}\mathrm{Al}$ has been studied with an alternative detector setup at the focal plane of the momentum achromat recoil separator MARS at Texas A University. We could detect protons down to an energy of 200 keV and determine the corresponding branching ratios. Contrary to results of previous $\ensuremath{\beta}$-decay studies, no strong proton intensity from the decay of the isobaric analog state (IAS) of the $^{23}\mathrm{Al}$ ground state at ${E}_{x}=7803$ keV in $^{23}\mathrm{Mg}$ was observed. Instead we assign the observed low-energy group ${E}_{p,\mathrm{c}.\mathrm{m}.}=206$ keV to the decay from a state that…
Relevance of β-delayed neutron data for reactor, nuclear physics and astrophysics applications
2023
Initially, yields (or abundances) and branching ratios of β-delayed neutrons (βdn) from fission products (Pn-values) have had their main importance in nuclear reactor control. At that time, the six-group mathematical approximation of the time-dependence of βdn-data in terms of the so-called "Keepin groups" was generally accepted. Later, with the development of high-resolution neutron spectroscopy, βdn data have provided important information on nuclear-structure properties at intermediate excitation energy in nuclei far from stability, as well as in nuclear astrophysics. In this paper, I will present some examples of the βdn-studies performed by the Kernchemie Mainz group during the past th…
Gamow-Teller Transitions Studied in ([sup 3]He, t) Reaction and Analogous β decay
2010
Due to the simplicity of the στ operator that causes Gamow‐Teller (GT) transitions, they are the most popular nuclear weak process in the Universe. The GT transitions in pf‐shell nuclei, for example, starting from stable Tz = +1 and proton‐rich Tz = +1 nuclei, where Tz = (N−Z)/2, play important roles in the supernova‐explosion or rp‐process nucleosynthesis. In the β‐decay study of pf‐shell nuclei, half‐lives can be measured rather accurately. On the other hand, in a high‐resolution (3He, t) charge‐exchange reaction at 0°, individual GT transitions up to high excitations can be studied. In order to derive reliable GT transition strengths B(GT), we present a unique analysis that combines the …
Meson and isobar degrees of freedom in light nuclei
1983
The role of mesonic and isobar degrees of freedom in various electromagnetic processes is reviewed for light nuclei. Special emphasis is laid on the deuteron, which allows the cleanest answers within the non-relativistic framework. The origin of the photonuclear enhancement with respect to both exchange forces and exchange currents is discussed in detail.