No abstract available

[en] A method for acertainning the activity by alpha spectroscopy with semiconductor detectors, of a solution of Uranium-232 is presented. It consists of the comparison with a Uranium-233 solution activity previously measured in a gridded ionization chamber of 2 π geometry. The total measurement uncertainty is about +- 0,02. (Author)

[en] Abstract only

[en] The concentrations of thorium isotopes in normal non-thorium exposed human ribs are reported. The measurement was carried out by means of chemical separation and analysis, electrodeposition, and alpha-spectrometry. The concentrations of ²³²th, ²³⁰Th, and ²²⁸Th in human ribs from 27 cases were in the range of 0.25 - 0.29, 0.01 - 2.15, and 1.06 - 15.01 pCi/kg wet weight, respectively. The values of ²³²Th, ²³⁰Th, and ²²⁸Th increased with age, and were fitted by the following expressions: Y = 0.38 + 0.01X (²³²Th), Y = 0.038 + 0.095X (²³⁰Th), Y = 2.96 + 0.01X (²²⁸Th). Where Y = the concentration of ²³²Th, ²³⁰Th, ²²⁸Th in pci/kg wet weight, X = the age in years

[en] A solvent extraction technique has been developed to improve the analysis and recoveries for Thorium-230. The emphasis of this technique is to improve productivity and precision over ion-exchange when using the Photon-Electron Rejecting Alpha Liquid Scintillation Spectrometer (PERALS). The Department of Energy (DOE) Formerly Utilized Sites Remedial Action Program (FUSRAP) currently is involved in characterizing sites that are contaminated with alpha emitting radionuclides which can not be detected with field instrumentation. This technique and equipment demonstrates the ability to be used for in-the-field analysis for all alpha emitting radionuclides with only minor modifications of in-laboratory procedures. The PERALS system offers 99.7% detection capability which greatly reduces counting times previously required for low activity samples. The solvent extraction technique coupled with the PERALS system significantly increases sample productivity and decreases unit cost per analysis. A description of the solvent extraction technique, the analytical instrumentation, and typical applications are discussed

[en] The contents of ²³²Th, ²³⁰Th and ²²⁸Th in the bones of normal men (not involved in thorium dust environment) were determined by means of radiochemical separation, electrodeposition and α-spectrometry. The results indicated that the mean and the standard deviation of the content of ²³²Th, ²³⁰Th and ²²⁸Th in bones were 31±19,23±18 and 62±39 Bq/kg (fresh weight) respectively. The mean annual dose resulted from ²³²Th, ²³⁰Th and ²²⁸Th in bone was estimated to be 0.031,0.027 and 0.085 mrad respectively. The ²³⁰Th content in bone showed to be in correlation with age. No significant difference in the contents of thorium isotopes was found between smokers and nonsmokers

[en] The gamma spectrometry technique has been used for masses determinations of uranium-233 and plutonium-239, granted by AERE-HARWELL. A high purity Ge semicondutor detector was used and the total efficiency curve was obtained for the counting system in the energy range 13 KeV to 135 KeV. The calculated values for the masses compared with that obtained by means of gravimetry technique. (author)

[en] Improved nuclear analysis, including the treatment of resonance and spatial self-shielding, coupled with an optimization procedure, has resulted in an improved performance estimate for the molten salt blanket. Net U-233 breeding ratio ranges between 0.58 and 0.63, and blanket energy multiplication ranges between 1.8 and 1.9

[en] Short communication

[en] Several years ago, we reported that there was an excited state of ²²⁹Th that occurred within a few electron volts of the ground state. Since that time, we have carried out an extensive series of measurements in an effort to obtain a value, rather than merely a limit, for the excitation energy of this level. This study has now been completed. Analysis of these data, which is still in progress, indicates that this level energy is 4.5 eV, with an estimated uncertainty of 1 eV