Double beta decay of 100Mo to the excited states of daughter nuclei has been studied using a 600 cm3 low-background HPGe detector and an external source consisting of 2588 g of 97.5% enriched metallic 100Mo, which was formerly inside the NEMO-3 detector and used for the NEMO-3 measurements of 100Mo. The half-life for the two-neutrino double beta decay of 100Mo to the excited View the MathML source01+ state in 100Ru is measured to be T1/2=[7.5±0.6(stat)±0.6(syst)]⋅1020 yrT1/2=[7.5±0.6(stat)±0.6(syst)]⋅1020 yr. For other (0ν+2ν)(0ν+2ν) transitions to the View the MathML source21+, View the MathML source22+, View the MathML source02+, View the MathML source23+ and View the MathML source03+ levels in 100Ru, limits are obtained at the level of ∼(0.25-1.1)⋅1022 yr∼(0.25-1.1)⋅1022 yr
During recent years, the assessment of possible radiological consequences of a terrorist attack associated with a release of radioactive substances (RaS) has been in the focus of interest of emergency preparedness and radiation protection specialists, as well as experts dealing with the dispersion of harmful substances in the atmosphere. Suitable tools for these analyses are applications of mathematical and physical models and simulation of this attack under 'realistic' conditions. The work presented here summarises the results of four tests, in which a RaS (a Tc-99 m solution) was dispersed over a free area with the use of an industrial explosive. Detection methods and techniques employed in these tests are described and values characterising the RaS dispersion--dose rates, surface activities in horizontal and vertical directions, volume activities, their space and time distributions and mass concentrations of aerosols produced after the explosion are presented and compared. These data will be applied to a comparison of outcomes of models used for the assessment of radiation accidents as well as in future field tests carried out under conditions of more complex geometry (indoor environment, terrain obstacles, etc.).
Radon is one of the main potential source of background for any rare event experiments like neutrinoless double beta decay or dark matter experiments. The Radon Trapping Facility (RTF) installed in 2004 at the Modane Underground Laboratory (LSM) has been running for almost 9 years providing a radon-purified air at the level of 10 mBq/m 3 compared to 20 Bq/m 3 in the laboratory. The radon suppression principle is based on radon physical adsorption using pumping cooled compressed air at-55 • C through a column filled with K48 activated charcoal. After disassembling of the RTF, the 2.6 m height charcoal column has been divided in several layers in order to study with different techniques the dynamic adsorption coefficient (Kfactor) as a function of the depth and the radon spatial trapping profile by measuring the 210 Pb activity. It has been demonstrated that after a decade of running, most of the radon adsorption capacity of the RTF remains constant excepted for the first 20 cm. A radon mean free path of about 30 cm has been derived in a coherent manner from two independent analysis leading to a radon suppression factor of the RTF ranging from 1 830 to 6 790. These results are consistent with the suppression factor of 2 000 measured during the operation of the RTF, proving its capacity to purify the radon in the LSM air by more than 3 orders of magnitude during 9 years. In addition to 210 Pb
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.