Search results for "Neutron capture"
showing 10 items of 86 documents
New supersymmetric quartet of nuclei in the A ∼ 190 mass region
2009
We present evidence for a new supersymmetric quartet in the A=190 region of the nuclear mass table. New experimental information on transfer and neutron capture reactions to the odd-odd nucleaus 194 Ir strongly suggests the existence of a new supersymmetric quartet, consisting of the 192,193 Os and 193,194 Ir nuclei. We make explicit predictions for the odd-neutron nucleus 193 Os, and suggest that its spectroscopic properties be measured in dedicated experiments.
Thermal neutron capture cross section of the radioactive isotopeFe60
2015
Background: Fifty percent of the heavy element abundances are produced via slow neutron capture reactions in different stellar scenarios. The underlying nucleosynthesis models need the input of neutron capture cross sections.Purpose: One of the fundamental signatures for active nucleosynthesis in our galaxy is the observation of long-lived radioactive isotopes, such as $^{60}\mathrm{Fe}$ with a half-life of $2.60\ifmmode\times\else\texttimes\fi{}{10}^{6}$ yr. To reproduce this $\ensuremath{\gamma}$ activity in the universe, the nucleosynthesis of $^{60}\mathrm{Fe}$ has to be understood reliably.Methods: An $^{60}\mathrm{Fe}$ sample produced at the Paul Scherrer Institut (Villigen, Switzerla…
Gyrotron-driven high current ECR ion source for boron-neutron capture therapy neutron generator
2014
Abstract Boron-neutron capture therapy (BNCT) is a perspective treatment method for radiation resistant tumors. Unfortunately its development is strongly held back by a several physical and medical problems. Neutron sources for BNCT currently are limited to nuclear reactors and accelerators. For wide spread of BNCT investigations more compact and cheap neutron source would be much more preferable. In present paper an approach for compact D–D neutron generator creation based on a high current ECR ion source is suggested. Results on dense proton beams production are presented. A possibility of ion beams formation with current density up to 600 mA/cm 2 is demonstrated. Estimations based on obt…
Radiative neutron capture on Pu242 in the resonance region at the CERN n_TOF-EAR1 facility
2018
The spent fuel of current nuclear reactors contains fissile plutonium isotopes that can be combined with uranium to make mixed oxide (MOX) fuel. In this way the Pu from spent fuel is used in a new reactor cycle, contributing to the long-term sustainability of nuclear energy. However, an extensive use of MOX fuels, in particular in fast reactors, requires more accurate capture and fission cross sections for some Pu isotopes. In the case of Pu242 there are sizable discrepancies among the existing capture cross-section measurements included in the evaluations (all from the 1970s) resulting in an uncertainty as high as 35% in the fast energy region. Moreover, postirradiation experiments evaluat…
Neutron capture cross sections for neutron-rich isotopes
1985
Average continuum (Hauser-Feshbach) and resonance (Breit-Wigner) neutron capture rates for neutron-rich isotopes, determined on the basis of recent experimental nuclear physics input parameters, are compared to earlier theoretical reaction rates commonly used in astrophysical model computations.
Low-spin mixed particle–hole structures in 185W
2005
Abstract The level structure of 185W has been studied using the prompt and delayed gamma–gamma coincidences from thermal neutron capture in 184W accompanied with the one-nucleon transfer reactions ( d , p ) and ( d , t ) with polarized beams. From these data and those of previous studies a total of 183 levels has been established for energies below 3 MeV. Many of these states have been grouped into rotational bands built on 28 intrinsic states of quasiparticle and quasiparticle-plus-phonon character. Although the DWBA analysis permitted definite spin–parity assignments for most of states a large number of particle transitions have ‘anomalous’ angular and asymmetry shapes with respect to the…
SU-FF-T-180: Dosimetric Characteristics of Tm-170 as a Radionuclide for Its Possible Use in Brachytherapy
2006
In clinical brachytherapy several types of photon sources are used, mainly Cs‐137, Ir‐192, I‐125, and Pd‐103. The Tm‐170 is a promising radionuclide for use in brachytherapy because of the low mean‐energy (46.75 keV or 66.39 keV if the lines below 10 keV are removed) and the possible high specific activity (2.21×1014 Bq/g for a half life of 128.6 days). Tm‐170 is produced in a nuclear reactor by neutron absorption of the natural Tm‐169 and decays mainly via β‐emission. The maximum energies of the β‐rays are 0.290 and 0.323 MeV. These β particles are thus absorbed in the source core and in the encapsulation cover producing bremsstrahlung that contributes significantly to the dose. These fact…
The Extremely Metal‐poor, Neutron Capture–rich Star CS 22892‐052: A Comprehensive Abundance Analysis
2003
High-resolution spectra obtained with three ground-based facilities and the Hubble Space Telescope (HST) have been combined to produce a new abundance analysis of CS 22892-052, an extremely metal-poor giant with large relative enhancements of neutron-capture elements. A revised model stellar atmosphere has been derived with the aid of a large number of Fe-peak transitions, including both neutral and ionized species of six elements.Several elements, including Mo, Lu, Au, Pt and Pb, have been detected for the first time in CS 22892-052, and significant upper limits have been placed on the abundances of Ga, Ge, Cd, Sn, and U in this star. In total, abundance measurements or upper limits have b…
Towards Laser Spectroscopy of Superheavy Elements
2016
The sensitivity of laser spectroscopic methods has been increased over the past two decades dramatically so that today the spectroscopy of superheavy elements appears on the horizon as a realistic option. For elements with Z > 100 no experimental atomic or ionic level structure information is known so far. These elements cannot be bread in high flux nuclear power reactors via successive neutron capture and \(\beta ^-\) decay but must be produced in accelerator-based nuclear fusion-evaporation reactions. Laser spectroscopic investigations at low rates take advantage of the storage of ions or atoms in rare gas traps. A first successful experiment was conducted only recently for the element no…
High performance 3D CZT spectro-imager for BNCT-SPECT: preliminary characterization
2018
The National Institute of Nuclear Physics (INFN) is supporting the 3CaTS project with the aim of developing a new Single Photon Emission Computed Tomography (SPECT) system for real time 10 B therapeutic dose monitoring in the binary experimental hadron therapy called Boron Neutron Capture Therapy (BNCT). BNCT is a highly selective tumour treatment based on the neutron capture reaction 10 B(n,α) 7 Li. The secondary particles have a high LET with ranges in tissues of the order of 10 μm (thus less than the mean cell diameter of few tens μm). Targeting the 10 B delivery towards cancer, the released energy lethally damages only the malignant cells sparing the normal tissues, thus enabling a cell…