Source-supporting foil effect on the shape of positron time annihilation spectra

Bertolaccini, M.; Zappa, L.

doi:10.1007/bf02711092

Cited by 57 publications

(11 citation statements)

References 5 publications

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“…The following table includes the calibration and correction values for both sources used in the laboratory. The intensity of the short annihilation lifetime component in the source is specific to the metal on which the salt is deposited, and is in good agreement with the value estimated using the formula taken from [19]:…”

Section: B Positron Annihilation Lifetime Spectroscopy (Pals)supporting

confidence: 82%

Thermal desorption gas chromatography and positron annihilation spectroscopy contribution to alpha decay studies in actinide-doped matrices

Roudil¹,

Jegou²,

Barthe³

et al. 2009

2009 1st International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and Their Applications

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A thermal desorption system coupled with a gas analyzer has been adapted and nuclearized to investigate He behavior in actinide-doped samples used to simulate alpha decay aging. This technique widely used in standard laboratories allows measurements of the helium balance and reduced diffusion coefficients, and a preliminary evaluation of helium locations (related to defects and thermal annealing). In our system implemented in a hot cell, small samples are annealed at up to 1100°C in controlled atmosphere. They are inserted in a 10 to 20 cm 3 vessel connected to a micro gas chromatography detector. Initial system calibration allowed concentration measurements within about 10%. Comparisons with the CNRS/CRPG rare gas analysis laboratory at Nancy, France, were applied on natural uranium oxides originating from Oklo (Gabon) and Mistamisk (Canada). The latest results obtained on Mistamisk samples are in good agreement, with a maximum relative deviation of 14%. The data were used to determine the activation energy of about 1 eV·at -1 . On (U,Pu)O 2 and PuO 2 samples the experiments highlight the impact of defects (up to 100 dpa) on He mobility. The defect population must now be characterized to improve our knowledge of He/defect interactions and mechanisms. In addition and synergy to the macroscopic release measurements by gas chromatography, positron annihilation spectroscopy, an effective nondestructive technique for vacancy defect investigation, was also developed and nuclearized in our hot cell laboratory as part of a project supported by the NOMADE and MATINEX research groups. Specific protocols for doped sample analysis were also developed and validated with UO 2 and (U,Pu)O 2 samples.

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Section: B Positron Annihilation Lifetime Spectroscopy (Pals)supporting

confidence: 82%

Thermal desorption gas chromatography and positron annihilation spectroscopy contribution to alpha decay studies in actinide-doped matrices

Roudil¹,

Jegou²,

Barthe³

et al. 2009

2009 1st International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and Their Applications

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“…During the PALS analysis, the a damaged level of the samples reached about 3.8 Â 10 15 a/g. From the recorded positron annihilation lifetime distribution, calculations were achieved after subtracting source annihilation and the foil contribution [12]. Positron lifetime characteristics in UO 2 and U 0.90 Am 0.10 O 2Àx are reported in Table 4.…”

Section: Characterization Of Defectsmentioning

confidence: 99%

Self-irradiation effects in dense and tailored porosity U1−yAmyO2−x (y=0.10; 0.15) compounds

Prieur

Jankowiak

Roudil

et al. 2011

Journal of Nuclear Materials

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“…In the figure, lifetime components arising from annihilations in the positron source material have been subtracted from the spectrum with intensity 4.0% for the 235-ps Al-foil component, 3.0% for 400-ps Na-22 salt component, and 0.18% for the 1500-ps positronium component. The intensity of the 235-ps component was calculated using a formula from Bertolaccini and Zappa [24]; it was not fitted. This reduces the chance of this component shadowing a sample related lifetime.…”

Section: A Lifetime Spectroscopymentioning

confidence: 99%

Compensating vacancy defects in Sn- and Mg-dopedIn2O3

et al. 2014

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MBE-grown Sn-and Mg-doped epitaxial In 2 O 3 thin-film samples with varying doping concentrations have been measured using positron Doppler spectroscopy and compared to a bulk crystal reference. Samples were subjected to oxygen or vacuum annealing and the effect on vacancy type defects was studied. Results indicate that after oxygen annealing the samples are dominated by cation vacancies, the concentration of which changes with the amount of doping. In highly Sn-doped In 2 O 3 , however, these vacancies are not the main compensating acceptor. Vacuum annealing increases the size of vacancies in all samples, possibly by clustering them with oxygen vacancies.

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Source-supporting foil effect on the shape of positron time annihilation spectra

Cited by 57 publications

References 5 publications

Thermal desorption gas chromatography and positron annihilation spectroscopy contribution to alpha decay studies in actinide-doped matrices

Thermal desorption gas chromatography and positron annihilation spectroscopy contribution to alpha decay studies in actinide-doped matrices

Self-irradiation effects in dense and tailored porosity U1−yAmyO2−x (y=0.10; 0.15) compounds

Compensating vacancy defects in Sn- and Mg-dopedIn2O3

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