Precise and direct determination of the half-life of 41Ca

2012 ◽  
Vol 88 ◽  
pp. 51-65 ◽  
Author(s):  
Gerhard Jörg ◽  
Yuri Amelin ◽  
Karsten Kossert ◽  
Christoph Lierse v. Gostomski
Keyword(s):  
Half Life ◽  
Direct Determination

Direct determination of the half-life of 187Re

1989 ◽  
Vol 53 (7) ◽  
pp. 1597-1606 ◽  
Author(s):  
Manfred Lindner ◽  
Douglas A Leich ◽  
G Price Russ ◽  
Jeanne M Bazan ◽  
Richard J Borg
Keyword(s):  
Half Life ◽  
Direct Determination

Influence of Lipid Pool Size on Bioaccumulation of the Insecticide Chlordane by Northern Redhorse Suckers (Moxostoma macrolepidotum)

1977 ◽  
Vol 34 (1) ◽  
pp. 89-97 ◽  
Author(s):  
J. R. Roberts ◽  
A. S. W. deFrietas ◽  
M. A. J. Gidney
Keyword(s):  
Half Life ◽  
Assimilation Efficiency ◽  
Direct Determination ◽  
Fish Tissue ◽  
Pool Size ◽  
Lipid Pool ◽  
Net Assimilation ◽  
Pollutant Bioaccumulation ◽  
Cis And Trans

An effect of the lipid pool size on the accumulation and clearance of cis- and trans-chlordane by northern redhorse suckers (Moxostoma macrolepidotum) has been demonstrated. A technique was developed using 203Hg-labeled methylmercury as a tracer, which permits the direct determination of the assimilation efficiency from food and the biological half-life of chlorinated hydrocarbons in terms of individual fish. Tissue retention of the insecticide chlordane in fish was directly proportional to the adiposity of the fish. For a fish containing 2% lipid, the half-life of the cis-isomer was 60 days and for the trans-isomer, 33 days. The net assimilation efficiency from food to fish tissue was also influenced by adiposity. These results on uptake and clearance, when used in a simple model for pollutant bioaccumulation, indicate that the steady state concentration of chlordane in fish will not exceed the concentration of chlordane in the diet unless the adiposity of the fish is high.

scholarly journals First direct determination of the 93Mo half-life

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
I. Kajan ◽  
S. Heinitz ◽  
K. Kossert ◽  
P. Sprung ◽  
R. Dressler ◽  
...  
Keyword(s):  
Half Life ◽  
Liquid Scintillation ◽  
Specific Activity ◽  
High Resolution Mass Spectrometry ◽  
Direct Determination ◽  
Chemical Separation ◽  
Decontamination Factor ◽  
Nuclear Facilities ◽  
Analysis Techniques

AbstractThis work presents the first direct measurement of the 93Mo half-life. The measurement is a combination of high-resolution mass spectrometry for the determination of the 93Mo concentration and liquid scintillation counting for determining the specific activity. A 93Mo sample of high purity was obtained from proton irradiated niobium by chemical separation of molybdenum with a decontamination factor larger than 1.6 × 1014 with respect to Nb. The half-life of 93Mo was deduced to be 4839(63) years, which is more than 20% longer than the currently adopted value, whereas the relative uncertainty could be reduced by a factor of 15. The probability that the 93Mo decays to the metastable state 93mNb was determined to be 95.7(16)%. This value is a factor of 8 more precise than previous estimations. Due to the man-made production of 93Mo in nuclear facilities, the result leads to significantly increased precision for modelling the low-level nuclear waste composition. The presented work demonstrates the importance of chemical separations in combination with state-of-the-art analysis techniques, which are inevitable for precise and accurate determinations of nuclear decay data.

The Direct Determination of I131 in Heterogeneous Fecal Specimens

1961 ◽  
Vol 41 (4) ◽  
pp. 380-384 ◽  
Author(s):  
Arthur F. Dratz ◽  
James C. Coberly
Keyword(s):  
Direct Determination

A New Method for Direct Determination of the Recoilless Fraction with Application to Magnetic Nanoparticles

2002 ◽  
Vol 721 ◽  
Author(s):  
Monica Sorescu
Keyword(s):  
Room Temperature ◽  
Average Particle Size ◽  
Direct Determination ◽  
Average Particle ◽  
Lattice Method ◽  
Recoilless Fraction ◽  
Single Room ◽  
Magnetite Particles ◽  
Physical Mixtures

AbstractWe propose a two-lattice method for direct determination of the recoilless fraction using a single room-temperature transmission Mössbauer measurement. The method is first demonstrated for the case of iron and metallic glass two-foil system and is next generalized for the case of physical mixtures of two powders. We further apply this method to determine the recoilless fraction of hematite and magnetite particles. Finally, we provide direct measurement of the recoilless fraction in nanohematite and nanomagnetite with an average particle size of 19 nm.

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