Column separation of tetravalent cerium fission products from trivalent rare earth radio-isotopes

Journal of Radioanalytical and Nuclear Chemistry - Rapid and efficient isolation of individual rare earth element (REE) radioisotopes from complex mixtures is necessary to support the fields of...     

Cumulative yields of short-lived xenon isotopes in the spontaneous fission of252Cf

Cumulative yields of short-lived xenon isotopes^137,138,139Xe have been determined in the spontaneous fission of²⁵²Cf, using a fast radiochemical separation method followed by gamma spectrometry. Xenon-137 yield is reported for the first time. The measured cumulative yields are converted to chain yields assuming normal charge distribution systematics for comparision with the literature data.     

Chemical states of iodine produced by the spontaneous fission of252Cf

The distributions of the chemical states of¹³¹I,¹³²I,¹³³I,¹³⁴I and¹³⁵I produced by the spontaneous fission of²⁵²Cf were investigated by the method of fractional precipitation separation in 6M NH₄OH solution followed by measurement of the X-ray spectrum of the samples with a Ge(Li) detector. The iodine fission fragments were separately collected in the matrices of NaNO₃, NaCl, dehydrated sodium sulfate, CH₃COONa·3H₂O, Na₃H₂IO₆, KI and NaIO₃ crystals. The results showed that the distribution of the chemical states was the function of the collection time, the nature of matrix materials and the type of iodine isotopes. The relative amount of the reduced states of¹³⁴I decreased with the increase of collection time in the matrix of NaNO₃. The ratio of the amount of reduced states to the total amount of the¹³⁴I was the highest (50.4%) in NaCl matrix and the lowest (9.4%) in Na₃H₂IO₆ matrix. The relative quantities of reduced states of¹³⁵I were the highest (58.5% and 97.7%) and that of¹³⁴I were the lowest (16.9% and 63.1%) in matrices of NaNO₃ and NaCl, respectively.     

Cumulative yields of the short-lived ruthenium isotopes in the spontaneous fission of252Cf

⁶⁷Ga is produced by the⁶⁶Zn(d,n) reaction at 9 MeV bombarding energy. Deuterons of about 30 A obtained from the T-11 Tandem accelerator are used to bombard targets of natural Zinc prepared by electroplating onto thick copper disks. Radiochemical separation of gallium is performed by using a cation exchange column. The optimum conditions for an efficient separation are given in detail.     

Neutron-activation analysis of vanadium in oils with californium-252

Results are given which have been obtained by the application of relatively small²⁵²Cf sources for the neutron-activation analysis of vanadium in oils. It could be shown that by optimization the geometrical conditions for activation and counting with a 24 μg²⁵²Cf source detection limits down to the order of 1 ppm vanadium are attainable; the absolute error, e.g., at 1.3 ppm is 0.32 ppm.     

Cumulative yields of short-lived isotopes of barium in the spontaneous fission of252Cf

Cumulative yields of short-lived/barium isotopes^{139, 141, 142}Ba have been determined in the spontaneous fission of²⁵²Cf, using fast radiochemical separation and gamma-ray spectrometry.¹⁴²Ba yield is reported for the first time. The measured cumulative yields are converted to chain yields, assuming normal charge distribution systematics for comparision with the literature data.     

Absolute determination of the spontaneous fission yield of252Cf by radiochemical method

The distribution of mass in the spontaneous fission of²⁵²Cf has been investigated by the radiochemical determination of the absolute fission yields for 35 mass chains. A summation of the mass-yield curve gives a summed value of 199.4% which is in very good agreement with the value of 200% in fission. The mean masses of the light and heavy group are located at 106.39 and 141.82, respectively. The average number of neutron per fisson is 3.79±0.12. The peak-to-valley ratio is larger than 370. The width at one tenth of the maximum of the light and heavy group are 26.7 and 26.8 mass number, respectively. A comparison of previous investigators has resulted in recommended yields for 35 mass chains.     

The chemical states of tellurium produced by spontaneous fission of252Cf

The distribution of the chemical states of tellurium isotopes produced by²⁵²Cf spontaneous fission, collected separately in the matrixes of NaCl, Kl, NaF, CH₃COONa·3H₂O, Na₂SO₄ and NaNO₃ crystals have been investigated. Two chemical states of tellurium isotopes maintained in these matrixes are Te(IV) and Te(VI). The relationships between the distribution of the chemical states of tellurium isotopes and the produced mode of tellurium, the chemical properties of collection matrixes, the time for collecting fission fragments are studied and the possible mechanism of the interactions of the fission products and the matrixes is discussed. The results show that the distribution of chemical states of tellurium isotopes depends on the chemical properties of the collection matrixes mainly.     

Cumulative yields of127gSn and128Sn in the spontaneous fission of252Cf

The potteries found on the Tremiti Isles (Italy, Adriatic Sea) have been characterized through their trace elements content. The goal of the work was to find out the number of ore deposits that supplied the clay used to manufacture the pottery. Neutron activation analysis has been employed for trace elements content determinations; the results have been statistically evaluated, clusterized and discussed.     

Determination of rare earth elements in mineral raw materials and rare earth industry products by neutron activation analysis

To determine REE in mineral raw materials, high purity RE metals and their compounds, neutron activation analysis with extraction chromatographic REE separation has been developed. Combination of the developed RE extraction and separation procedures with subsequent -spectrometric analysis of the RE radionuclides allows to determine their content with the lower detection limit –10^–5–10^–8%. The relative standard deviation is 0.2–0.3.     

Yields of fission products with masses A=131 to 135 for the fast neutron induced fission of U-238

Yields of eleven fission products with masses A=131 to 135 have been determined for the reactor neutron induced fission of²³⁸U by means of radiochemical separation combined with high-precision Ge(Li) -ray spectrometry. The charge distribution in the isobaric chains 131 to 134 and the isotopic distribution of₅₂Te have been studied.     

Determination of manganese in ores by activation analysis using a californium-252 neutron source

A²⁵²Cf neutron source has been used to analyse manganese in ores such as pyrolusite, rodonite (manganese silicate) and blends used in dry-batteries. Samples with about 150 mg and standards of manganese dioxide were irradiated for about 20 min and counted using a well-type NaI(Tl) scintillation counter and scaler, with or without pulse-height discriminator between the detector and the scaler. The interferences of nuclear reactions⁵⁶Fe(n,p)⁵⁶Mn and⁵⁹Co(n,α)⁵⁶Mn were studied, as well as problems in connection with neutron shadowing during irradiation, gamma-rays attenuation during counting and influence of granulometry of samples. Some of the samples were also analysed by wet-chemical method (sodium bismuthate) in order to compare results.     

Copper mining and mill analyses by γ-rays from capture of californium-252 neutrons

Copper mill materials from Utah and Nevada and rock cores from a geothermal drill hole at the Valies Grande Caldera in New Mexico were irradiated at the Los Alamos Scientific Laboratory with neutrons from a californium-252 source (about 10¹⁰ n s^-1), and the capture γ-rays were measured. The copper response, based on the 6.89-MeV double escape line, agreed sufficiently well with the known chemical composition of the materials to indicate usefulness of this technique for exploring copper deposits and for monitoring metallurgical extraction processes.