Behavior of iodine implanted in highly oriented pyrolytic graphite (HOPG) after heat treatment

Mukhawana, Mxolisi B.; Theron, C.C.; Malherbe, J.B.; Berg, N.G. van der; Botha, André; Grote, Wiebke; Wendler, E.; Wesch, W.; Chakraborty, Purushottam

doi:10.1016/j.nimb.2011.07.040

Cited by 7 publications

(7 citation statements)

References 3 publications

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“…We have concentrated on aspects such as the diffusion of several fission products implanted in SiC, carbon, and the effects of vacuum annealing on radiation damage introduced by the relatively low energy implantation ions [2][3][4][5][6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Effect of Xe ion (167 MeV) irradiation on polycrystalline SiC implanted with Kr and Xe at room temperature

Hlatshwayo

O’Connell

Skuratov

et al. 2015

J. Phys. D: Appl. Phys.

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The effect of swift heavy ion (Xe 167 MeV) irradiation on polycrystalline SiC individually implanted with 360 keV Kr and Xe ions at room temperature to fluences of 2×10 16 cm -2 and 1×10 16 cm -2 respectively, was investigated using transmission electron microscopy (TEM), Raman spectroscopy and Rutherford backscattering spectrometry (RBS). Implanted specimens were each irradiated with 167 MeV Xe +26 ions to a fluence of 8.3×10 14 cm -2 at room temperature. It was observed that implantation of 360 keV Kr and Xe ions individually at room temperature amorphized the SiC from the surface up to a depth of 186 and 219 nm respectively. Swift heavy ion (SHI) irradiation reduced the amorphous layer by about 27 nm and 30 nm for the Kr and Xe samples respectively. Interestingly, the reduction in the amorphous layer was accompanied by the appearance of randomly oriented nanocrystals in the former amorphous layers after SHI irradiation in both samples. Previously, no similar nanocrystals were observed after SHI irradiations at electron stopping powers of 33 keV/nm and 20 keV/nm to fluences below 10 14 cm -2 . Therefore, our results suggest a fluence 2 threshold for the formation of nanocrystals in the initial amorphous SiC after SHI irradiation.Raman results also indicated some annealing of radiation damage after swift heavy ion irradiation and the subsequent formation of small SiC crystals in the amorphous layers. No diffusion of implanted Kr and Xe was observed after swift heavy ion irradiation.

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Section: Introductionmentioning

confidence: 99%

Effect of Xe ion (167 MeV) irradiation on polycrystalline SiC implanted with Kr and Xe at room temperature

Hlatshwayo

O’Connell

Skuratov

et al. 2015

J. Phys. D: Appl. Phys.

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“…After obtaining the thickness of the injected xenon ion layer by blocking the cross-section factor, the diffusion coefficient of xenon was calculated by the diffusion equation, and the diffusion coefficient of Xe 26+ at 650°C was calculated to be D(Xe,650°C) = 6.49 × 10 -20 m 2 /s. The mathematical model of isotropic material diffusion in this study is based on the assumption that the rate of transfer of diffusing material per unit area through the cross-section is proportional to the measured concentration gradient perpendicular to the cross-section [15].…”

Section: Resultsmentioning

confidence: 99%

“…(2) The diffusion coefficient was measured by injecting Xe 26+ at a dose of 4.8×10 15 ions/cm 2 into SSNG at room temperature and annealing the expansion at a constant temperature of 650°C for 9 h. The concentration of xenon was determined by the value of FWHM of Xe 26+ peak half height width on the RBS energy spectrum before and after isothermal annealing. The diffusion coefficient of Xe 26+ ions was measured by Rutherford backscattering (RBS) for the first time after isothermal annealing at 650°C for 9 h. The diffusion coefficient D(Xe,650°C) = 6.49×10 -20 m 2 /s, which shows that the nanopore graphite SSNG has an excellent ability to inhibit xenon diffusion.…”

Section: Discussionmentioning

confidence: 99%

Measurement of the Diffusion Coefficient of Xenon in Self-Sintered Nanopore Graphite for Molten Salt Reactor

Li,

Lei,

Zhang

et al. 2023

Preprint

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The economics and safety of reactors can be affected by the diffusion of fission products into graphite. Xenon (Xe) fission products diffusing into the graphite is the most critical neutron absorber and poison that can slow down or stop the chain reaction. The transport parameters for inhibiting the xenon diffusion in graphite are therefore the utmost scientific problem. Self-sintered nanopore-isotropic (~ 40nm) graphite (SSNG) derived from green pitch coke can decrease Xe diffusion into the graphite. In this study, a method for measurement of diffusion coefficients of fission products diffusion in graphite by Rutherford backscattering spectrometry (RBS) was reported. The SSNG substrates were implanted with Xe at a dose of 4.8×1015 ions/cm2 and energy of 7 MeV. The RT-implanted samples were annealed in a vacuum at 650°C for 9 h. The implanted and annealed samples were characterized by RBS. The diffusion coefficient D(Xe,650°C) is 6.49×10-20 m2/s. The results indicate the excellent ability to inhibit Xe diffusion of the SSNG and present significance in designing and evaluating the safety of nuclear reactors.

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“…The kinematic factors, backscattered energy, and channel numbers for the elements are also shown. The mathematical model of isotropic material diffusion in this study was based on the assumption that the rate of transfer of diffusing material per unit area through the cross-section was proportional to the measured concentration gradient perpendicular to the cross-section [28]:…”

Section: Rutherford Backscattering Analysismentioning

confidence: 99%

“…cross-section was proportional to the measured concentration gradient perpendicular to the cross-section [28]:…”

Section: Elementmentioning

confidence: 99%

Measurement of the Diffusion Coefficient of Xenon in Self-Sintered Nanopore Graphite for Molten Salt Reactor

Li,

Lei,

Zhang

et al. 2023

View full text Add to dashboard Cite

The economics and safety of reactors can be affected by the diffusion of fission products into graphite. Xenon (Xe) fission products diffusing into graphite is the most critical neutron absorber and poison that can slow down or stop the chain reaction. The transport parameters for inhibiting the xenon diffusion in graphite are therefore an important scientific problem. Self-sintered nanopore-isotropic (~40 nm) graphite (SSNG) derived from green pitch coke can decrease Xe diffusion into graphite. In this study, the surface morphology and microstructural evolution in graphite before and after irradiation, as well as after annealing, were studied with different characterization methods. A method for the measurement of diffusion coefficients of fission products’ diffusion in graphite using Rutherford backscattering spectrometry (RBS) was also reported. The SSNG substrates were implanted with Xe at a dose of 4.8 × 1015 ions/cm2 and energy of 7 MeV. The RT-implanted samples were annealed in a vacuum at 650 °C for 9 h. The implanted and annealed samples were characterized using RBS. The diffusion coefficient D (Xe, 650 °C) was 6.49 × 10−20 m2/s. The results indicate SSNG’s excellent ability to inhibit Xe diffusion and are significant for designing and evaluating the safety of nuclear reactors.

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Behavior of iodine implanted in highly oriented pyrolytic graphite (HOPG) after heat treatment

Cited by 7 publications

References 3 publications

Effect of Xe ion (167 MeV) irradiation on polycrystalline SiC implanted with Kr and Xe at room temperature

Effect of Xe ion (167 MeV) irradiation on polycrystalline SiC implanted with Kr and Xe at room temperature

Measurement of the Diffusion Coefficient of Xenon in Self-Sintered Nanopore Graphite for Molten Salt Reactor

Measurement of the Diffusion Coefficient of Xenon in Self-Sintered Nanopore Graphite for Molten Salt Reactor

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