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  • Author or Editor: N. Lavi x
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Abstract  

99Mo−99mTc generators were prepared starting from irradiated molybdenum metal instead of MoO3 in order to use reactor irradiation space more economically. The adsorption of molybdenum as sodium molybdate on different kinds of alumina was investigated. The effect of the pH of the column and the aqueous phase concentration of molybdenum were studied and related to the elution yield of99mTc. A study of the radiation damage effect indicated that generators having a high elution efficiency of 90% could be prepared in the 100–600 mCi range. The losses of99Mo were minimized to 10−5-10−4% and those of alumina to 2–5 μg/ml eluate.

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Abstract  

The iodine isotopes produced by thermal neutron fission of235U were separated by a fast chemical procedure, with a separation yield of 95%. The gamma-ray energies and relative intensities in the decay of131I,132I,133I,134I and135I were determined using a Ge(Li) detector.

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Abstract  

The concentration of cadmium, cobalt, molybdenum, selenium, titanium and vanadium in natural water was determined by neutron activation analysis, using a prior preconcentration by a coprecipitation. The preconcentration of these trace elements was accomplished by converting the dissolved trace ions into the pyrrolidine dithiocarbonate (PDC) chelates, followed by coprecipitation on Bi as well as Pb-PDC chelates. This technique has been applied to the elements in natural waters: fresh water and sea waters (Mediterranian and Dead Sea).

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Abstract  

Instrumental neutron activation analysis (INAA) was applied to the rapid determination of magnesium in the botanical reference materials Beech Leaves-100 and Spruce Needles-101. The magnesium content was quantitatively determined by measuring the gamma-ray photopeak at 1014 keV of the short-lived radionuclide27Mg (9.46 m). The magnesium concentrations in the two materials were found to be 834.6±50.2 g·g–1 dry weight and 618.6±36.2 g·g–1, respectively. When assaying a 0.1 g sample under the same experimental conditions the limit of detection is 30 g of Mg.

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Abstract  

It was found that Cu and Se can be relatively easily and accurately determined by preconcentration of Cu and Se prior to the determination by neutron activation analysis with the short-lived IRN's (Indicator Radionuclides)66Cu and77mSe. The method consists of wet acid digestion followed by coprecipitation with lead tetramethylenedithiocarbamate. The precipitate was collected, irradiated and counted. The validity of the method was confirmed both by internal checks, as the measurement also by75Se and by the use of two reference material of biological origin. The limit of detection was found to be 20 ng Se and 50 ng Cu for a 0.1 g sample.

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Abstract  

The concentrations of titanium and vanadium in biological material, human blood serum, were determined by neutron activation analysis, using a prior coprecipitation with Pb/PDC/2 as well as Bi/PDC/3. Titanium and vanadium were quantitatively determined by measuring the gamma ray photopeaks of the short-lived radionuclides51Ti /5.8 min/ and52V /3.75 min/, respectively. The concentrations ranged from 105.7 to 131.9 ng ml–1 /Ti/ and from 1.30 to 6.05 ng ml–1 /V/. The detection limits for titanium and vanadium under the present experimental conditions were found to be 70 and 0.7 ng for 1 ml of blood serum sample, respectively.

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Abstract  

The (n, n′) reaction with the epithermal and fast neutrons of a nuclear reactor has been studied for activation analysis of Sr, Cd, In, Ba, Hf, Os, Au, Hg and Pb. For some elements (In, Os, Au, Hg and Pb) the use of a cadmium sheet reduced the activity by less than a factor of two, while the interferences from the most abundant elements have been reduced by more than two orders of magnitude.

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Abstract  

The absolute concentrations of iodine, bromine and chlorine in milk, have been determined by epithermal neutron activation followed by high resolution gamma-ray spectrometry. Two kinds of milk commonly consumed in Israel have been investigated. The concentration of iodine, bromine and chlorine were found to be 0.18–0.30 g/ml, 2.02–2.85 g/ml and 0.65 mg/ml, respectively. The method is fast, selective, accurate and highly sensitive.

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Abstract  

Fast determination of Fe by Instrumental Neutron Activation Analysis through the formation of56Mn from both55Mn(n,)56Mn and56Fe(n, p)56Mn by using both reactor neutron and epithermal neutron irradiation is described and evaluated.

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Abstract  

Fast determination of Cr by Instrumental Neutron Activation Analysis through the formation of52V from52Cr/n,p/52V by using both reactor and epithermal neutron irradiation is described and evaluated.

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