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  • 1
    Electronic Resource
    Electronic Resource
    Half-life of plutonium-241: Past and present (1987)
    Springer
    Journal of radioanalytical and nuclear chemistry 109 (1987), S. 183-200 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Half-life of241Pu is of great importance in nuclear technology. In view of large variation in the values (13–15 y) reported till 1974 in literature, efforts have been made in different laboratories to determine this half-life with high precision and accuracy. In our laboratory, it has been determined by different methods which may be classified in two categories, viz. (1) parent decay method, and (2) daughter growth method. In the parent decay method, change in isotope ratios241Pu/239Pu,241Pu/240Pu and241Pu/242Pu was studied periodically by a thermal ionization mass spectrometer. Single as well as double ratio method was used to calculate the half-life. In the daughter growth method, the half-life was obtained in four independent ways. These were (1) alpha spectrometry taking239Pu and242Pu separately as reference isotopes and studying periodically the increase in alpha activity ratio, (2) alpha proportional counting for observing periodically the change in total alpha activity, (3) isotope dilution alpha spectrometry using243Am as a spike, (4) isotope dilution mass spectrometry using243Am as a spike. In all these methods, synthetic mixtures were prepared for achieving high precision and accuracy in different measurements. Based on the results obtained in this laboratory and the values reported by other laboratories, a half-life value of 14.4±0.1 y is recommended. The paper reviews the past history, puts forth the present status, highlights the current trends for studying the effect of chemical composition of plutonium on the half-life of241Pu and presents the future requirements for achieving higher accuracy in the half-life of241Pu.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02117535
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  • 2
    Electronic Resource
    Electronic Resource
    Alpha spectrum evaluation method for the simultaneous determination of plutonium, americium and curium (1986)
    Springer
    Journal of radioanalytical and nuclear chemistry 107 (1986), S. 263-277 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A method based on the geometric progression decrease of the counts in the far tail of the alpha spectrum is described for the simultaneous determination of plutonium, americium and curium by alpha spectrometry. For evaluating the precision and accuracy, synthetic mixtures were prepared from solutions of enriched isotopes and sources were prepared by direct evaporation method using tetraethylene glycol /TEG/ as a spreading agent and electropolished stainless steel discs as the backing material. Precision and accuracy of about 1% is demonstrated in the determination of244Cm/239Pu,241Am/239Pu,244Cm/233U,241Am/233U and239Pu/233U alpha activity ratios using a 450 mm2 silicon surface barrier detector.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02166620
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  • 3
    Electronic Resource
    Electronic Resource
    Determination of plutonium by alpha spectrometry (1992)
    Springer
    Journal of radioanalytical and nuclear chemistry 156 (1992), S. 111-118 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Determination of actinides in the environmental and bioassay samples is important in view of the following factors: increasing energy production by nuclear reactors; environmental contamination due to fallout from nuclear weapons testing and burn up of nuclear-powered satellites; the growing emphasis on the desirability of a cleaner environment; and public concern over the potential hazards associated with nuclear reactors. Among the various actinides, plutonium is one of the most important due to the large amounts produced in the nuclear fuel cycle. Further, the extremely low levels of plutonium in the different biological and environmental samples demand the development of precise, accurate, and sensitive methods to arrive at meaningful conclusions from the results obtained in various studies. In addition to various other techniques available, alpha spectrometry is commonly used.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02037427
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  • 4
    Electronic Resource
    Electronic Resource
    Determination of the half-lives of transactinium isotopes by relative activity method (1986)
    Springer
    Journal of radioanalytical and nuclear chemistry 103 (1986), S. 213-223 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Relative activity method offers the potentiality of providing half-life values over a wide range in a short time for different α-emitting transactinium isotopes. The method involves the preparation of a synthetic mixture using another isotope of the same element followed by the determination of atom ratio and α-activity ratio by thermal ionization mass spectrometry and α-spectrometry, respectively. A double dilution technique is described which helps in maintaining the atom ratios as well as α-activity ratios close to unity so that these could be determined with high precision and accuracy. Results obtained on the half-lives of232U,238Pu,242Pu and243Am using double dilution technique in relative activity method are summarized. Requirements, advantages and applications of this technique for determining the half-lives of other transactinium isotopes are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02165602
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  • 5
    Electronic Resource
    Electronic Resource
    Preparation and characterization of234U for mass spectrometry and alpha-spectrometry (1998)
    Springer
    Journal of radioanalytical and nuclear chemistry 230 (1998), S. 307-309 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract 234U of high isotopic purity (〉99 atom%) as well as of high radiochemical, purity was separated from aged238Pu prepared by neutron irradiation of237Np. Methodologies based on ion exchange and solvent extraction procedures were used to achieve high decontamination factor from238Pu owing to the very high α-specific activity of238Pu (2800 times) in comparison to that of234U. Isotopic composition of purified234U was determined by thermal ionisation mass spectrometry. Alpha spectrometry was used for checking the radiochemical purity of234U with respect to concomitant α-emitting nuclides. The separated234U will be useful for different investigations using mass spectrometry and alpha spectrometry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02387487
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  • 6
    Electronic Resource
    Electronic Resource
    A comparative study of234U/238U alpha-activity ratios determined by alpha-spectrometry and calculated from mass spectrometric data (1998)
    Springer
    Journal of radioanalytical and nuclear chemistry 230 (1998), S. 265-267 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract 234U/238U α-activity ratios determined by α-spectrometry (AS) and those calculated from the atom ratio data using the half-life values are compared in some of the isotopic reference materials of uranium and a few other uranium samples. For α-spectrometry, electrodeposited sources were prepared and a large area passivated ion implanted (IPE) detector (450 mm2) was used for recording the α-spectra. The isotopic composition of U was determined by thermal ionisation mass spectrometry (TIMS) and the recommended half-life values of234U and238U were used to calculate the α-activity ratio. It is observed that234U/238U α-activity ratios calculated from the atom ratio data are consistently high, with a mean difference of about 5%, when compared to the α-spectrometry results. This discrepancy warrants confirmation by a few more laboratories and suggests redetermination of the half-life values of234U and238U.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02387476
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  • 7
    Electronic Resource
    Electronic Resource
    Electrodeposition of milligram amounts of uranium on electropolished stainless steel disks (1991)
    Springer
    Journal of radioanalytical and nuclear chemistry 154 (1991), S. 103-110 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Investigations have been carried out for the electrodeposition of milligram amounts of uranium on electropolished stainless steel disks with an objective of preparing good quality sources for α-spectrometric studies on uranium. The parameters studied include the variation of electrodeposition yield as a function of voltage, time, distance between the cathode and anode, and the volume of 0.2M ammonium oxalate solution. The conditions selected for preparing good quality sources with nearly 100% yield were: electrodeposition voltage 25 V, time of deposition 15 min, volume of 0.2M ammonium oxalate solution in the cell 4 ml and a distance of 2 cm between the cathode and anode. The sources prepared using this method have been used successfully for the α-spectrometric determination of234U/238U ratios in uranium samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02162668
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  • 8
    Electronic Resource
    Electronic Resource
    Precision and accuracy in the determination of plutionium-239 /uranium-233, americium-241/ uranium-233 and curium-244 /uranium-233 alpha activity ratios by alpha spectrometry (1986)
    Springer
    Journal of radioanalytical and nuclear chemistry 106 (1986), S. 295-307 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Determination of239Pu/233U,241Am/233U and244Cm/233U alpha activity ratios is required when using233U as a tracer for the determination of plutonium, americium and curium by alpha spectrometry. Precision and accuracy in the determination of these alpha activity ratios was evaluated by preparing synthetic mixtures from solutions of enriched isotopes of239Pu,241Am,244Cm and233U. Separate synthetic mixtures were prepared for each of the three alpha activity ratios. The sources from the synthetic mixtures were prepared by direct evaporation method using tetra ethylene glycol /TEG/ as a spreading agent, alpha spectra were recorded by employing solid state silicon surface barrier detectors coupled to a 4 K analyzer and the alpha spectra were evaluated by a method based on the geometric progression decrease for the far tail of the spectrum. Large area detector /i.e. 450 mm2/ was observed to reduce the effect of nonhomogeneous distribution, if any, of the two elements present in the source. Precision and accuracy of about 1% is demonstrated for the determination of239Pu/233U,241Am/233U and244Cm/233U alpha activity ratios using large area silicon surface barrier detector.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02162493
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  • 9
    Electronic Resource
    Electronic Resource
    Experimental evaluation of the characteristic features of passivated ion implanted and surface barrier detectors for alpha spectrometry of plutonium (1988)
    Springer
    Journal of radioanalytical and nuclear chemistry 120 (1988), S. 29-39 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Experimental evaluation of a commonly used silicon surface barrier detector and of the recently introduced passivated ion implanted detector for alpha spectrometry is reported in terms of FWHM, peak to valley ratio, tail parameter and % tail contribution per unit alpha activity ratio using electrodeposited sources of plutonium prepared on platinum backing material. For this purpose, detectors of nearly the same diameter were employed (100 mm2 silicon surface barrier detector with a diamater of 1.13 cm and 80 mm2 passivated ion implanted silicon detector with a diameter of 1.01 cm). It is shown that the recently introduced passivated ion implanted detectors give smaller tailing effects. But there is no significant difference between the two detectors used in the present work w.r.t. FWHM and peak to valley ratios. Further, it is observed that the peak to valley ratio can be used to get an idea about240Pu/239Pu and241Am/238Pu alpha-activity ratios in the sample.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02037848
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  • 10
    Electronic Resource
    Electronic Resource
    Studies on the use of passivated ion implanted detectors in alpha spectrometry for the determination of actinides (1990)
    Springer
    Journal of radioanalytical and nuclear chemistry 145 (1990), S. 389-401 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract An experimental evaluation of the recently available passivated ion-implanted detectors, which appear promising for high resolution α-spectrometry, is presented in terms of % tail contribution per unit α-activity ratio, peak to valley ratio, and resolution /FWHM/. The two IPE detectors with areas of 20 mm2 and 450 mm2 were used for comparing these parameters. It is seen that the smaller area detector provides a better resolution for single nuclide sources, but there is no significant difference for sources containing nuclides with close lying α-energies, e.g.,239Pu,240Pu. Further, the large area detector gives less tail contribution and should be preferred to minimize the error in α-activity ratio determinations. However, the small area detector offers a possibility of qualitative or semiquantitative determination of nuclides with close lying α-energies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02163711
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