Search results for "CAPTURE"
showing 10 items of 463 documents
Nuclear matrix elements for rare decays
2010
Abstract Neutrinoless double electron capture ( 0 ν ECEC) is being vigorously investigated because of the possibility of it telling us something about the absolute mass scale of the neutrino. The resonant 0 ν ECEC is particularly interesting due to the potentially huge enhancement of its decay rate by a resonance condition. Recently the mass differences of two atom pairs were measured in order to study the enhancement of the 0 ν ECEC rates of 74Se and 112Sn. The associated nuclear matrix elements were also evaluated. The neutrino mass can also be detected by using beta decays with low Q values. Related to this we have investigated the second-forbidden decay branch of 115In with its ultra-lo…
Electron capture on116In and implications for nuclear structure related to double-βdecay
2013
The electron capture decay branch of ${}^{116}$In has been measured to be $[2.46\ifmmode\pm\else\textpm\fi{}0.44(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.39(\mathrm{syst}.)]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ using Penning trap-assisted decay spectroscopy. The corresponding Gamow-Teller transition strength is shown to be compatible with the most recent value extracted from the $(p,n)$ charge-exchange reaction, providing a resolution to longstanding discrepancies. This transition can now be used as a reliable benchmark for nuclear-structure calculations of the matrix element for the neutrinoless double-$\ensuremath{\beta}$ decay of ${}^{116}$Cd and other nuclides.
A novel experimental system for the KDK measurement of the 40K decay scheme relevant for rare event searches
2020
Potassium-40 ($^{40}$K) is a long-lived, naturally occurring radioactive isotope. The decay products are prominent backgrounds for many rare event searches, including those involving NaI-based scintillators. $^{40}$K also plays a role in geochronological dating techniques. The branching ratio of the electron capture directly to the ground state of argon-40 has never been measured, which can cause difficulty in interpreting certain results or can lead to lack of precision depending on the field and analysis technique. The KDK (Potassium (K) Decay (DK)) collaboration is measuring this decay. A composite method has a silicon drift detector with an enriched, thermally deposited $^{40}$K source …
Muon Capture At Large Energy Transfer
1977
Abstract A novel and parameter free approach to μ capture is introduced. The inclusive capture rate at maximal energy transfer is connected with the off-mass shell s and p wave scattering lengths for pions. Inside PCAC a rigorous lower bound for the rate results. The vector current contributions are shown to be insignificant. In a numerical illustration it is shown that this picture qualitatively explains the high energy nucleons emitted in μ capture.
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…
β-decay study of150Er,152Yb, and156Yb: Candidates for a monoenergetic neutrino beam facility
2011
The beta decays of ^{150}Er, ^{152}Yb, and ^{156}Yb nuclei are investigated using the total absorption spectroscopy technique. These nuclei can be considered possible candidates for forming the beam of a monoenergetic neutrino beam facility based on the electron capture (EC) decay of radioactive nuclei. Our measurements confirm that for the cases studied, the EC decay proceeds mainly to a single state in the daughter nucleus.
Wien filter for cooled low-energy radioactive ion beams
2002
A Wien filter for cooled radioactive ion beams has been designed at Ion Guide Isotope Separator On Line technique (IGISOL). The purpose of such device is to eliminate doubly charged ions from the mass separated singly charged ions, based on q=+2→q=+1 charge exchange process in an ion cooler. The performance of the Wien filter has been tested off-line with a discharge ion source as well as on-line with a radioactive beam. The electron capture process of cooled q=+2 ions has been investigated in a radiofrequency quadrupole ion cooler with varying partial pressures of nitrogen. Also, the superasymmetric fission production yields of 68<A<78 nuclei have been deduced.
Properties of the 12C 10 MeV state determined through β-decay
2005
16 pages, 1 table, 10 figures.-- PACS nrs.: 23.40.-s; 26.20.+f; 27.20.+n.-- Printed version published Oct 3, 2005.
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…