[en] The effects of ionising radiations on the activity of protein A from Staphylococcus aureus has been investigated. Reaction with H·, ·OH and e^-_aq results in loss of protein A activity, the values of the inactivating efficiencies being 0.016, 0.003 and 0.0014 respectively. Reaction with (SCN)^-₂ increases the rate of the inactivation process (inactivating efficiency=0.007), compared to that of ·OH radical. This latter species, as well as ·OH, destroy tyrosine residues (as is evidenced by a progressive loss of tyrosine fluorescence) and is accompanied by formation of a tyrosine-linked protein A dimer. The dimer has been isolated using FPLC and shows no activity towards IgG.(author)

[en] The fabrication and performance evaluation of single-crystal diamond refractive X-ray lenses with a paraboloid of rotation form factor for focusing X-rays in two dimensions simultaneously are reported.

[en] The creation of thin, buried, and electrically conducting layers within an otherwise insulating diamond by annealed ion implantation damage is well known. Establishing facile electrical contact to the shallow buried layer has been an unmet challenge. We demonstrate a new method, based on laser micro-machining (laser ablation), to make reliable electrical contact to a buried implant layer in diamond. Comparison is made to focused ion beam milling.

[en] Conversion electron Moessbauer spectroscopy measurements have been made on a diamond sample synthesized by chemical vapour deposition. The sample was implanted with 70 keV ⁵⁷Fe to a dose of 5x10¹⁴ cm^-2 and Moessbauer measurements were made on the as-implanted sample and after annealing at temperatures of 600 K, 950 K and 1470 K. The spectra at the lower temperatures were characterized by broad doublets, but the annealing at 1470 K resulted in dramatic decrease in the intensity of the doublet components, and the appearance of a strong single line with an isomer shift of δ=-0.90(5) mm/s and areal intensity of 30%, and a weaker line (5%) with δ=+0.07(4). Arguments are presented to attribute the single lines to substitutional and interstitial Fe, respectively. In contrast, identical measurements made on diamonds synthesized in the high temperature high pressure process showed little evidence of any strong single line component.

[en] We report reflection anisotropy spectroscopy (RAS) measurements of the oxidized (001) surface of a type IIb natural diamond. These measurements were made possible due to recent developments in diamond surface preparation. We compare RAS results from the hydrogenated, clean and oxidized C(001) surface and demonstrate that RAS is sensitive to the structural transition of the surface from the 2 x 1 reconstruction of the clean surface to the 1 x 1 reconstruction of the oxidized surface.

[en] Design of a UV sensor based on an yttrium-iron garnet/diamond layered cavity is presented. The operation principle of the sensor is based on the change in the spin-wave dispersion law and, consequently, in the frequency and Q-factor of eigenmodes of the cavity under study upon appearance of free carriers generated by UV light. (paper)

[en] Experimental results for narrowband filter based on yttrium iron garnet film epitaxially grown on gadolinium gallium garnet substrate have been shown. The principle of operation of the filter is based on excitation of Lamb modes in the substrate. We demonstrated also that the use of single crystal diamond as a substrate will significantly reduce the phase noise of the designed optoelectronic microwave generator. (paper)

[en] ¹⁰B doped p-type diamond samples were subjected to neutron transmutation reaction using thermal neutron flux of 0.9 × 10¹³ cm⁻² s⁻¹ and fast neutron flux of 0.09 × 10¹³ cm⁻² s⁻¹. Another sample of epilayer grown on type IIa (110) single crystal diamond substrate was subjected to equal thermal and fast neutron flux of 10¹⁴ cm⁻² s⁻¹. The defects in the diamond samples were previously characterized by different methods. In the present work, thermal conductivity of these diamond samples was determined at room temperature by transient thermoreflectance method. The thermal conductivity change in the samples as a function of neutron fluence is explained by the phonon scattering from the point defects and disordered regions. The thermal conductivity of the diamond samples decreased more rapidly initially and less rapidly for larger neutron fluence. In addition, the thermal conductivity in type IIb diamond decreased less rapidly with thermal neutron fluence compared to the decrease in type IIa diamond subjected to fast neutron fluence. It is concluded that the rate of production of defects during transmutation reaction is slower when thermal neutrons are used. The thermal conductivity of epilayer of diamond subjected to high thermal and fast neutron fluence is associated with the covalent carbon network in the composite structure consisting of disordered carbon and sp² bonded nanocrystalline regions

[en] In this paper we review and provide an overview to the understanding of the chemical vapor deposition (CVD) of diamond materials with a particular focus on the commonly used microwave plasma-activated chemical vapor deposition (MPCVD). The major topics covered are experimental measurements in situ to diamond CVD reactors, and MPCVD in particular, coupled with models of the gas phase chemical and plasma kinetics to provide insight into the distribution of critical chemical species throughout the reactor, followed by a discussion of the surface chemical process involved in diamond growth.

[en] A hydrogen-filled capillary discharge waveguide operating at kHz repetition rates is presented for parameters relevant to laser plasma acceleration (LPA). The discharge current pulse was optimized for erosion mitigation with laser guiding experiments and MHD simulation. Heat flow simulations and measurements showed modest temperature rise at the capillary wall due to the average heat load at kHz repetition rates with water-cooled capillaries, which is promising for applications of LPAs such as high average power radiation sources