N o r m a le u n d a n o m a le A b s o r p tio n v o n R ö n tg e n -S tr a h le n in G e r m a n iu m u n d S iliciu m Normal and anomalous absorption of X-rays in Germanium and Silicon A brief discussion of G. Moliere's generalized dynamical theory is given with respect to the interpretation of the experimental data ! % 1,/Z-o I obtained by means of the Borrmann effect.In order to compare theory and experiment photoelectric absorption cross sections for Silicon and Germanium have been calculated over the X-ray energy range from 5 to 25 keV. Linear ab sorption coefficients measured by us and other authors agree with theory within a few per cent.Taking the Debye-Waller factor into account, the same theoretical data have been used to cal culate J X

The i-gel is a supraglottic airway with a gel-like thermoplastic cuff. It has been suggested that the seal around the larynx improves following insertion. Perhaps the most intuitive hypothesis proposed for this is that cuff softening occurs during warming from ambient to body temperature. We investigated this using a food industry texture analyser over a wide temperature range. Size 2 and 3 i-gels were secured to a platform within a temperature-controlled water bath, which was in turn mounted on a texture analyser test stand. Both water and i-gel cuff temperatures were recorded. A spherical probe was advanced 4 mm into the surface of each i-gel at a rate of 1 mm.s , then retracted at the same rate while the upward pressure on the probe was recorded. Three runs made at each of the 11 temperatures (10 °C to 60 °C, 5 °C increments) gave 105,864 data points, from which values for hardness (the peak force on the probe at maximum indentation), and resilience (the rate at which the material recovers its original shape) were calculated. Over 10 to 60 °C, the smallest hardness value expressed as a proportion of the largest was 88.2% and 89.8% for size 2 and 3 i-gels, respectively, and for resilience these were 92.8% and 86.2%, respectively. Over room temperature to body temperature range (21-37.4 °C), hardness decreased by 3.15% and increased by 0.47% for i-gel sizes 2 and 3, respectively, whereas resilience values decreased by 1.85% and 2.68%, respectively. Cuff hardness and resilience did generally reduce with warming, but the effect was minimal over temperature ranges that may be encountered during clinical use.

Photoelectric atomic absorption cross sections have been calculated by means of hydrogen-like eigenfunctions for the atomic K, L, M and N sub-shells of the elements Z = 6 to 54, using revised screening constants and an extension of the theory. The absorption cross sections have been further separated into dipole and quadrupole components so that the numerical data can also be applied to the Borrmann effect.

Theoretical (normal incidence) Bragg reflectivities from diamond are determined for several low/medium order reflections and found to be ≈︁ 10% higher than those from Si or Ge. The angular positions of simultaneous (Renninger) reflections which reduce these intensities are also given and the possibilities of additional (secondary diffuse scattering) reflections are discussed. The calculations simulate the conditions expected from a diamond single crystal, used as a normal incidence SR‐monochromator in a hard X‐ray free electron laser (XFEL).

WSR‐topographic results for three different Type I diamonds are compared with their respective IR spectra for selection as SR‐(undulator‐)monochromators. Beam‐line pollutants/graphitization on diamond surfaces are discussed with respect to AES scans and deterioration in Bragg reflectivity.