Search results for "Alpha decay"
showing 10 items of 121 documents
Investigation of a gas-catcher/ion guide system using alpha-decay recoil products
2002
Abstract 219Rn recoils from the alpha decay of 223Ra have been used to study the efficiency and delay time distributions of a gas-catcher/ion guide system. Ions with charge states up to +4 were coming out of the gas cell. Combining efficiency and delay time measurements, ion survival times in plasma free conditions can be deduced.
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…
Beta delayed alpha emission from the neutron deficient rare earth isotopes [sup 152]Tm and [sup 150]Ho
2011
The study of beta‐delayed proton emission is a well known method to aid the determination of the beta strength distribution in nuclei far from the stability line. At the neutron deficient side of the nuclear chart the process of proton or alpha emission from excited states is energetically allowed when one goes far enough from stability. However, beta‐delayed alphas have seldom been measured for nuclei heavier than A = 20. Here we present a study of the beta‐delayed alpha‐particle emission from 152Tm and 150Ho and their importance in the full B(GT) distribution. © 2011 American Institute of Physics
The 2n-Evaporation Channels In the Fusion of [sup 4,6]He with [sup 206,208]Pb
2009
Excitation functions of the reaction products were measured for the reactions induced by 4,6He projectiles on 206,208Pb targets, leading to the same compound nucleus. This was accomplished by using the stacked‐foil‐activation technique. The identification of the reaction products (accumulated in the Pb targets) was done by their radioactive alp ha decays. The excitation functions for the 2n evaporation channels were obtained at energies below the sub‐Coulomb barrier region. A large value of the fusion cross section was observed in the case of the reaction induced by the weakly bound 6He projectile.
Production and Decay of Element 114: High Cross Sections and the New NucleusHs277
2010
The fusion-evaporation reaction Pu-244(Ca-48, 3-4n)(288,289)114 was studied at the new gas-filled recoil separator TASCA. Thirteen correlated decay chains were observed and assigned to the production and decay of (288, 289)114. At a compound nucleus excitation energy of E* = 39.8-43.9 MeV, the 4n evaporation channel cross section was 9.8(-3.1)(+3.9) pb. At E* = 36.1-39.5 MeV, that of the 3n evaporation channel was 8.0-(+7.4)(4.5) pb. In one of the 3n evaporation channel decay chains, a previously unobserved alpha branch in (281)Ds was observed ( probability to be of random origin from background: 0.1%). This alpha decay populated the new nucleus (277)Hs, which decayed by spontaneous fission…
α-decay of the new isotopePo187: Probing prolate structures beyond the neutron mid-shell at N = 104
2006
The new neutron-deficient isotope $^{187}\mathrm{Po}$ has been identified in the complete fusion reaction $^{46}\mathrm{Ti}$+$^{144}\mathrm{Sm}$\ensuremath{\rightarrow}$^{187}\mathrm{Po}$+$3n$ at the velocity filter SHIP. Striking features of the $^{187}\mathrm{Po}$ \ensuremath{\alpha} decay are the strongly-hindered decay to the spherical ground state and unhindered decay to a surprisingly low-lying deformed excited state at 286 keV in the daughter nucleus $^{183}\mathrm{Pb}$. Based on the potential energy surface calculations, the $^{187}\mathrm{Po}$ ground state and the 286 keV excited state in $^{183}\mathrm{Pb}$ were interpreted as being of prolate origin. The systematic deviation of t…
αdecay studies of very neutron-deficient francium and radium isotopes
2005
Very neutron-deficient francium and radium isotopes have been produced in fusion evaporation reactions using $^{63}\mathrm{Cu}$ and $^{65}\mathrm{Cu}$ ions on $^{141}\mathrm{Pr}$ targets and $^{36}\mathrm{Ar}$ ions on $^{170}\mathrm{Yb}$ targets. The gas-filled recoil separator RITU was employed to collect the fusion products and to separate them from the scattered beam. The activities were implanted into a position-sensitive silicon detector after passing through a gas-counter system. The isotopes were identified using spatial and time correlations between the implants and decays. Two new \ensuremath{\alpha} decaying radium isotopes, $^{201}\mathrm{Ra}$ and $^{202}\mathrm{Ra}$, were identi…
Fine structure in the α decay of high-spin isomers in Lu155 and Hf156
2018
Fine structure in the a decay of high-spin isomers in Lu-155( 25/2(-)) and Hf-156(8(+))has been studied for the first time using alpha gamma- coincidence analysis. Three new a decays from Lu-155(25 ...
γ-Ray Spectroscopy at the Limits: First Observation of Rotational Bands inLr255
2009
The rotational band structure of Lr-255 has been investigated using advanced in-beam gamma-ray spectroscopic techniques. To date, Lr-255 is the heaviest nucleus to be studied in this manner. One ro ...