Showing papers on "Fluence published in 1970"
TL;DR: In this article, the crystallinity of ion-implanted silicon has been investigated using ion mass and ion fluence dependences of divacancy formation as measured by the characteristic 1.8 μ absorption band.
Abstract: The crystallinity of ion-implanted silicon has been investigated using ion mass and ion fluence dependences of divacancy formation as measured by the characteristic 1.8 μ absorption band. Room temperature, nonchanneled implants of 400-keV B11, Zn64, and Sb121 ions were performed to maximum fluences of 1014 ions/crn2 for Sb and Zn and to 2 × 1015 ions/cm2 for B. The results are interpreted on the basis of ion energy spent in atomic processes per unit volume, e, within the implanted layer. For e ≤ 1019 keV/cm3 the energy to form a divacancy (1.5 ± 0.5 keV) is nearly ion independent. Maxima appear in the divacancy densities at ∼1013 Sb ions/cm2 and ∼2 × 1013 Zn ions/cm2 where e ≤ 1020 keV/cm3. The divacancy density for B implantation did not exhibit a distinct maximum at E = 1020 keV/cm3, but continued to increase with fluence. The B results are attributed to defect motion because divacancies are observed beyond the calculated depth for energy deposition after a high fluence B implant. In addition t...
55 citations
TL;DR: In this article, the authors measured the deposition profiles for the pulsed electron beams in solid radiation sensitive plastics and indicated a pronounced range shortening at charge fluences greater than 0.5 microcoulombs/cm2.
Abstract: The deposition profiles for the pulsed electron beams in solid radiation sensitive plastics have been measured and indicate a pronounced range shortening at charge fluences greater than 0.5 microcoulombs/cm2. This range shortening, due to charge trapping and the attendant internal field, reaches a constant value in the absence of apparent breakdown which is independent of charge fluence at current densities greater than about 33 amps/cm2 for mean electron energies of 1.35 MeV. The dose depth profiles at charge fluences greater than 0.5 microcoulomb/ cm2 exhibit a linearly decreasing back edge which extrapolates to approximately 35% of the low fluence range and a low intensity tail extending to greater than 55% of this range. As the charge fluence increases, the tail of the dose profile decreased in relation to the forward portion. These phenomena are interpreted in terms of a charge deposition model including radiation induced conductivity.
11 citations
TL;DR: Hall effect and electrical conductivity measurements of defect annealing in 1 ohm-cm n-type and 2 ohm cm p-type silicon were made following neutron irradiation at ∼50°C as discussed by the authors.
Abstract: Hall effect and electrical conductivity measurements of defect annealing in 1 ohm-cm n-type and 2 ohm-cm p-type silicon were made following neutron irradiation at ∼50°C. Measurements were also made following 400-keV B11 ion implantation into a 100 ohm-cm n-type Si substrate. As the neutron fluence is increased the electrical effects of the damage eventually outweigh those of the chemical dopants, and further changes in the electrical properties become small. Conversely, significant electrical recovery upon annealing begins only when the electrical effects of the remaining damage become comparable to those of the chemical dopants. This condition will occur at higher anneal temperatures for higher fluence irradiations. The neutron fluence dependence of the damage and the annealing is interpreted in terms of the neutron energy per cm3. E, spent in atomic processes divided by the number/cm3, N, of electrically active dopants. When E/N ≤ 0.5 keV the electrical measurements show that the predominant de...
11 citations
TL;DR: In this article, the mechanical property changes in Charpy-V and tensile speciments have been determined as a result of irradiation at 585°F in accelerated, vessel wall and thermal control exposure locations of the Big Rock Point Reactor.
10 citations
01 Jan 1970
TL;DR: In this paper, the microstructure of annealed AISI Type 304 and type 316 stainless steels has been characterized by transmission electron microscopy as a function of fast reactor irradiation at fluence levels from 4×1021 to 7×1022 n per sq cm (E>0.1 mev) and at irradiation temperatures from 370° to 700°C.
Abstract: The microstructure of annealed AISI Type 304 and type 316 stainless steels has been characterized by transmission electron microscopy as a function of fast reactor irradiation at fluence levels from 4×1021 to 7×1022 n per sq cm (E>0.1 mev) and at irradiation temperatures from 370° to 700°C. Several irradiation produced defect types where found: voids, Frank faulted loops, perfect loops, dislocation networks, and precipitates. Void number density obeys a power law relationship to fluence, wherein the exponent increases with increasing temperature from 0.8 to 1.4 over the irradiation temperatures investigated. The void size is nearly independent of fluence and increases with increasing temperature. The upper limit irradiation temperature for void formation is about 650° to 700°C. The density and size of Frank faulted loops followed trends similar to those found for voids to temperatures of ∼550°C where unfaulted loops, perfect loops, and dislocation networks coexist. These experimental results do not confirm predictions of recently acvanced models of void formation. The major deficiency of these models appears to be the nucleation rate. Accordingly, empirical nucleation rates were used to formulate a diffusion-controlled void growth model. This model was found to closely describe experimentally determined void growth kinetics.
2 citations
TL;DR: In this article, various curve-fitting techniques to fit Gaussian functions to photopeaks were discussed and actual fluence values were determined using the sum peak method by counting foil which were irradiated simultaneously with the thermoluminescent dosimeters.
2 citations