Gamma counting

Approaching formation bed boundaries are detected by concurrent separation and displacement of the high and low gamma counts. These are shown in Figure 4-271 at measured depth intervals (7970-7980 ft) and (8010-8020 ft). 

Byrne AR, Komosa A. 1993. Possibilities for determination of241 Am in environmental samples by gamma counting, with and without radiochemistry. Sci Total Environ 130/131 197-206. 

Ballestra et al. [32] described a radiochemical measurement for determination of "technetium in rain, river, and seawater, which involved reduction to technetium (IV), followed by iron hydroxide precipitation and oxidation to the heptavalent state. Technetium (VII) was extracted with xylene and electrode-posited in sodium hydroxide solution. The radiochemical yield was determined by gamma counting on an anticoincidence shield GM-gas flow counter. The radiochemical yield of 50 to 150 litre water samples was 20-60%. 

Lumen of the small intestine Pb Ultracentrifugation, Gamma counting 48)... 

Plasma and Urine As X-ray Spectrometry Gamma counting Fractionation of arsenic metabolites formed after in vivo incorporation experiments with As 53)... 

The calculated adsorption coefficients (K) are presented in Table VII. K (alpha) refers to results from alpha counting the wafers and solutions, while K (gamma) refers to results from gamma counting. K (filter) refers to results from the alpha counting of wafers and filtered solutions. 

The distribution coefficients calculated from the alpha counting data are given in Table VIII. The gamma counting of the solutions is still in progress. The symbols are the same as used previously. For K (alpha), the counting precision is + 10 percent for the U, Am and Cm samples and + 20-30 percent for the Np and Pu samples. For K (filter), the counting precision is + 10 percent for U, + 10-20 percent for Np, Am and Cm and +30-40 percent for the Pu samples. 

This procedure made it possible to measure concomitantly the releases of 140Ba and 91Sr from the particles since at the temperatures of the anneals these nuclides are highly retained as sorbed species by the graphite crucibles (13). The release of the metallic nuclides is determined by gamma counting the empty crucibles. 

Fig. 1. Gel permeation chromatography of an antibody-toxin conjugate reaction mixture. The reaction mixture obtained following the conjugation of a mouse monoclonal antibody (50 mg) and [l25I]-labeled abrin A chain was chromatographed on a column of Sephacryl S-200 (SF), dimensions 80 cm x 2.6 cm (id). Fractions eluting from the column were monitored spectrophotometrically at 280 nm (—) to measure total protein, and by gamma counting (—) to measure the A chain in its free or conjugated form. The hatched area indicates a typical pooled conjugate preparation.

The coupons were gamma counted to determine residual or fixed activity. 

After both sets of experiments were completed, the ground-water was drained from the cells and selective chemical extractions of the granite cell walls were performed. The cells were filled with 0.5 mol/L CaCl solution and stirred continuously for 72 h to displace exchangeable radionuclides. After a rinse with demineralized water to remove residual CaCl- solution, the cells were filled with KTOX solution and stirred ror 24 h to remove radionuclides associated with oxyhydroxides. All solutions were analyzed by gamma spectrometry to determine the amounts of radionuclides extracted. Residual activity was measured by direct gamma counting of the cells. 

The chemical yields were determined by gamma-counting techniques. The sample contained a number of radioactive isotopes of gadolinium prior to isotope separation. 

Figure 2.10 shows the activity of137Cs in residents of the Harwell area from 1957 to 1988, as measured by external gamma counting in vivo (Kang,1989). The peak in 1987, due to fallout from Chernobyl, was much smaller than that in 1965, due to weapon tests. 

After the completion of MnOj separation, the water sample is transferred to the proper size polyethylene processing container. Adjust to pH 1-4 with nitric acid, add AMP as a slurry in water to extract the caesium (use 0.2 g AMP/1 of sample), stir the sample thoroughly and let the AMP settle, filter or decant the supemate (discard the supemate or save for Sr analysis, if required), separate the AMP by centrifugation and purify the Cs for beta or gamma counting. 

A12. Ashcroft, J., Gamma-counting of iodine-125 with a metal-loaded liquid scintillator. Anal. Biochem. 37, 268-275 (1970). 

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