Search

New estimated values are given for the decay and radiation characteristics of 129I derived from information published in the world literature up to 2003.

New estimated values of the decay and radiation characteristics of the radionuclide 155Eu, obtained using information published in the world literature up to 2003, are presented.

A draft for certifying reference data is presented as recommended values for the energies and absolute probabilities of emission for characteristic x-rays and low-energy gamma rays, together with the half-lives of the radionuclides 44Ti + 44Sc, 54Mn, 55Fe, 57Co, 65Zn, 109Cd, 207Bi, and 241Am. The recommended values have been obtained by analysis and selection from published estimated and experimental data on the basis of the information available in January 2003.

Estimated values of the half-life, the energy and absolute emission probability of alpha-particles for radionuclides, forming part of the standard spectrometric alpha-radiation sources: 226Ra with daughter decay products 233U, 238Pu, and 239Pu, are presented as a draft of standard reference data. The recommended values are obtained by analyzing and selecting published estimated and experimental data (up to December 2000).

New estimates of the decay and radiation characteristics of93mNb,111In, and170Tm that take into account data published up to 1999 are presented.

Abstract: A simple method is described for rapidly determining the activity of alpha-emitting radionuclides in a plane source which is based on measuring the counting rate in a detector under fixed geometry conditions for two positions of the source.

Abstract: During a reestimation of the half-lives of 42 radionuclides used to calibrate x-ray and γ-ray detectors a comparison was made between statistical procedures for obtaining the final errors of the estimated values. A rule is proposed for regulating the errors of the estimated values which assumes an increase in the error as a function of the mutual consistency of a set of data determined by the χ2 value.

In view of the present nucleosynthesis picture, an impotant role of radioactive nuclides is emphasized. Some recent works concerning a study of radionuclide decay data as a test of nucleosynthesis physical conditions are reviewed.

The present status of our understanding of natural synthesis of heavy nuclei in an astrophysical process of rapid neutron capture is reviewed. Particular emphasis is placed on the discussion of r-process duration and the importance of the nuclear constants including beta-delayed fission probabilities.

This article reviews recent work on the possible variability of basic physical constants, such as the charge of the electron e, Planck's constant h and the gravitational constant G. The problem was first raised by Dirac as early as 1937. Its present state is here discussed, together with new suggestions which include Gamow's hypothesis that the fine-structure constant varies directly with time (e2/hc ∞ t), the hypothesis (e2 ∞t, h ∞ t, G ∞ t) and the hypothesis (e4 ∞ t, h2 ∞t, G=constant).The conclusion is that at the present time the invariability of the charge of the electron and Planck's constant is hardly to be questioned, whereas the invariability of the constant of gravitation cannot be considered as finally proved. Some recent geological data point to a possible change in G with time.

Recommended energies are given for reference gamma rays in the decay of156Eu and156Tb in the photonenergy range 0.8–1.2 MeV with errors of a few electron volts, which are derived from data on gamma transitions from levels of156Gd occurring in (n?) reactions and the decays of156Eu and156Tb.

It is shown that Big Bang nucleosynthesis constraints on the mirror Universe are not an absolutely rigorous test.