Γ-ray Emission Probabilities Research Articles

Photon emission probabilities per decay of 226Ra and 232Th in equilibrium with their daughter products

Abstract γ-Ray emission probabilities per decay for the most abundant transitions in nuclides of the 226 Ra and 232 Th decay chain in radioactive equilibrium were determined by measuring the γ-ray emission rates with calibrated Ge(Li) spectrometers. Care has been taken in the determination of the activity of the sources and finding a radium source which is emanation leak-proof. For the 226 Ra decay, x-ray-emission probabilities were additionally measured.

Identification of a new isotope,168Dy

A previously unreported nuclide,168Dy, has been identified and found to have a half-life of 8.5+-0.5 min. The activity was produced in the spontaneous fission of252Cf and transported via a He jet system to a rapid radiochemical separative facility where the Dy fraction was removed from the mixed fission products. The assignment of this activity to168Dy decay was based on the presence of five γ rays in the chemically separated Dy fraction which were associated with the decay of an 8.5-min activity and on the observation of the grow-in and subsequent decay of the daughter, 2.98-min168Ho, with approximately an 8-min half-life. The γ-ray emission probabilities have been determined.

γ-Ray emission probability for the decay of 143Ce

The emission probabilities of the 57- and 293-keV γ-rays emitted in the decay of 33.0-h 143Ce have been measured by 4π β-γ coincidence counting and Ge(Li) spectrometric techniques to be (12.3 ± 0.3) and (42.8 ± 0.4) γ-rays per 100 decays, respectively. The relative intensities for 13 other γ-rays emitted in the decay of 143Ce have also been measured.

Emission probabilities and energies of γ-ray transitions from the 239Pu decay

To aid in the quantitative assay of 239Pu by means of γ-ray spectrometry, we have made precise measurements of the emission probabilities of six of the prominent γ-rays associated with the decay of 239Pu. The γ-ray emission rates were measured using calibrated Ge spectrometers. The decay-rate calibration was based on a measurement of the α-emission rate by NBS. α-Ray energies were also measured. For six precisely measured lines the energy values obtained are 51.624(1), 129.296(1), 203.550(5), 332.845(5), 375.054(3) and 413.713(5) keV and respective γ-ray emission probabilities are 27.1(5), 6.41(5), 0568(4), 1.547(12) and 1.455(9) photons per 10 5 decays. Relative γ-ray intensities were also determined for about 55 additional transitions.

Emission probabilities and energies of the prominent γ-ray transitions from the 240Pu decay

To permit increased precision in the quantitative assay of 240Pu by means of γ-ray spectrometry, we have remeasured the emission probabilities of the three prominent γ-rays associated with the decay of 240Pu. The γ-ray emission rates were measured using calibrated Ge spectrometers. The decay-rate calibration was based on a measurement of the α-emission rate by NBS. Precise values for the γ-ray energies were also measured. The following results were obtained: 45.244(2), 104.234(6) and 160.308(3) keV for the γ-ray energies, and 43.15(9), 7.18(7) and 0.402(4) photons per 10 5 decays for the respective γ-ray emission probabilities.

γ-ray emission probabilities for the decays of 141La and 142La

The emission probabilities of the 1354-keV γ-ray emitted in the decay of 141La and the 641-keV γ-ray emitted in the decay of 142La have been measured to be (1.643 ± 0.021) and (47.4 ± 0.5) γ-rays per 100 decays, respectively. The half-lives were measured to be (3.92 ± 0.03) h for 141La and (91.1 ± 0.5) min for 142La.

Gamma-ray emission probabilities of the fission products 144Ce 144Pr, 106Rh, 95Zr

The fission products 144Ce 144Pr, 106Rh and 95Zr play an important role in the burn-up determination of fuel elements by means of γ-ray spectrometry. One of the crucial quantities in this field is the absolute γ-ray emission probability (intensity) for which values available in literature have not the desirable accuracy of 1–2%. By using Ge(Li)-spectrometers of known efficiency and sources calibrated by 4πβ-γ-coincidence methods, we determined absolute γ-ray emission probabilities of 144Ce 144Pr, 106Rh and 95Zr with an uncertainty of ±1% for the main γ-rays.