Investigation of the fundamental constants stability based on the reactor Oklo burn-up analysis

The burn-up for SC56-1472 sample of the natural Oklo reactor zone 3 was calculated using the modern Monte Carlo codes. We reconstructed the neutron spectrum in the core by means of the isotope ratios: $^{147}$Sm/$^{148}$Sm and $^{176}$Lu/$^{175}$Lu. These ratios unambiguously determine the spectrum index and core temperature. The effective neutron absorption cross section of $^{149}$Sm calculated using this spectrum was compared with experimental one. The disagreement between these two values allows to limit a possible shift of the low laying resonance of $^{149}$Sm even more . Then, these limits were converted to the limits for the change of the fine structure constant $\alpha$. We found that for the rate of $\alpha$ change the inequality $|\delta \dot{\alpha}/\alpha| \le 5\cdot 10^{-18}$ is fulfilled, which is of the next higher order than our previous limit.Comment: 16 pages, 7 figure

Detection of hidden explosives and drugs

Technical discussions of advanced mass spectrometry methods for explosives and drug detection are presented. The discussions are part of an effort to develop fast neutron alternative technologies and optimal synergistic detection systems. Topics covered include: (1) general assessment of detection applications of neutronic techniques, (2) the US Argonne National Laboratory inelastic scattering approach; (3) the Russian Kurchatov Institute elastic scattering approach, and (4) benefits of combining the Argonne and Kurchatov approaches. Specific areas for modeling and analysis are noted. 11 refs., 8 figs

Application of unified composite detectors for measuring neutron spectra

Bryzgalov VI, Demidov AM, Dikarev V, et al. Application of unified composite detectors for measuring neutron spectra. Atomic Energy. 2008;104(4):299-307.The results of computational-experimental studies of the parameters of the energy spectra of neutrons from the nuclear facilities of the Russian Science Center Kurchatov Institute which have different core structures, reflectors, parameters, and type of fuel elements are presented. The measurements were performed using the methods of resonance activation unified composite detectors. Individual measurement results are presented