On a method for the solution of the diffraction problem (Two-dimensional case)

Enhanced Conversion of X-Rays into Visible Light in Thin Composite Layers (Composite Anthracene-PbCl[sub 2] Screens)

“…[11] it follows that ~c "-6 cm -1 [12] and from Eq. [7] that O" c --" 64 crn -1 [13] The fact that ac >> Tm can be attributed both to the pronounced internal reflection of the composite (due to the difference in the refractive indices of the PbC12 grains and the anthracene matrix) and to the fact that the degree of reabsorption is higher in the anthracene samples (larger penetration depth of the incident x-rays) than in the composite samples. The reabsorption tends to decrease the intensity of the short-wave luminescence and to increase the intensity of the longwave luminescence via the photon cascade process (7,(12)(13)(14).…”

“…[7] that O" c --" 64 crn -1 [13] The fact that ac >> Tm can be attributed both to the pronounced internal reflection of the composite (due to the difference in the refractive indices of the PbC12 grains and the anthracene matrix) and to the fact that the degree of reabsorption is higher in the anthracene samples (larger penetration depth of the incident x-rays) than in the composite samples. The reabsorption tends to decrease the intensity of the short-wave luminescence and to increase the intensity of the longwave luminescence via the photon cascade process (7,(12)(13)(14). In consequence the mean absorption coefficient of the anthracene samples will approach to the absorption coefficient of the luminescent light of 450 nm wavelength (~450 ~ 5 cm -z) (14,15) while that of the composite samples will tend more to the absorption coefficient of the luminescent light of 420 nm wavelength, being of the order of 100 cm -1 (14).…”

“…As the demand for larger substrate diameters (2 in. and greater) arose to meet the needs of advancing IC technologies, there was a general shift from flame fusion to Czochralski grown material, although at least one organization has adopted the approach of developing methods for the growth of large diameter flame fusion spinel (13). In the case of sapphire, the flame fusion and Czochralski material are chemically identical; therefore, the same conditions can be used for the deposition of silicon on both types of substrates.…”