Internal conversion

About: Internal conversion is a research topic. Over the lifetime, 2412 publications have been published within this topic receiving 32625 citations.

Thermoluminescence dating: beta‐dose attenuation in quartz grains

Abstract: Correction factors for attenuation of beta radiation by spherical quartz grains embedded in ceramics were obtained for grain diameters ranging from 0.005 to 10.0 mm. The calculation was based on the absorbed-dose distributions for point-isotopic beta sources listed by Berger, in conjunction with the scaling procedure developed by Cross, and included beta particles, internal conversion electrons, and Auger electrons emitted by /sup 40/K, and the /sup 232/Th and /sup 238/U series.

Evaluation of theoretical conversion coefficients using BrIcc

Abstract: A new internal conversion coefficient database, BrIcc has been developed which integrates a number of tabulations on internal conversion electron (ICC) and electron–positron pair conversion coefficients (IPC), as well as Ω ( E 0 ) electronic factors. A critical review of general formulae and procedures to evaluate theoretical ICC and IPC values are presented, including the treatment of uncertainties in transition energy and mixing ratio in accordance with the Evaluated Nuclear Structure Data File. The default ICC table, based on the Dirac–Fock calculations using the so called “Frozen Orbital” approximation, takes into account the effect of atomic vacancies created in the conversion process. The table has been calculated for all atomic shells and to cover transition energies of 1–6000 keV and atomic numbers of Z = 5 –110. The software tools presented here are well suited for basic nuclear structure research and for a range of applications.

Observation of correlated narrow-peak structures in positron and electron spectra from superheavy collision systems.

Abstract: We have observed that the positrons associated with a narrow peak in the positron spectrum from U+Th collisions are correlated with the simultaneous emission of electrons whose energy spectrum also contains a narrow peak. The mean energies and widths of the two peaks are equal within measurement errors. Neither the coincidence peak intensity nor the energy distributions of the positrons and electrons can be accounted for by known nuclear internal conversion processes. Similar observations have also been made in the Th+Th and Th+Cm collision systems.

Electrons in Finite-Sized Water Cavities: Hydration Dynamics Observed in Real Time

Abstract: We directly observed the hydration dynamics of an excess electron in the finite-sized water clusters of (H_2O)^-_n with n = 15, 20, 25, 30, and 35. We initiated the solvent motion by exciting the hydrated electron in the cluster. By resolving the binding energy of the excess electron in real time with femtosecond resolution, we captured the ultrafast dynamics of the electron in the presolvated (“wet”) and hydrated states and obtained, as a function of cluster size, the subsequent relaxation times. The solvation time (300 femtoseconds) after the internal conversion [140 femtoseconds for (H_2O)^-_35] was similar to that of bulk water, indicating the dominant role of the local water structure in the dynamics of hydration. In contrast, the relaxation in other nuclear coordinates was on a much longer time scale (2 to 10 picoseconds) and depended critically on cluster size.