Performance of the ASTERIX III high power iodine laser
For more than 500 shots the 1 TW iodine laser Asterix III has demonstrated high reliability for light-plasma-interaction experiments. Improved laser parameters and new measurements of light pulse properties are reported.
Measurement of kinetic parameters relevant to the operation of an electron‐beam initiated atomic iodine laser
Parameters relevant to the operation of an electron‐beam initiated atomic iodine laser, which would lase on the transition 5 2P1/2 (I*)→5 2P3/2 (I), have been measured by pulse radiolysis. Kinetic data for the parent compound quenching of I* were obtained by variation of the parent compound pressure at constant buffer gas pressure and observing I* decay rates versus time. Deactivation rates for perfluoroalkyl iodides were found to be much lower than for the corresponding alkyl iodides. Values obtained (in cm3 molec−1 s−1) are as follows: CH3I, (2.0±0.1)×10−13; C2H5I, (5.0±0.3)×10−13; CF3I, (8.8±0.3)×10−16; C2F5I, (9.7±1.0)×10−15; n‐C3F7I, (2.5±0.2)×10−15; i‐C3F7I, (1.7±0.1)×10−15; n‐C4F9I, (1.8±0.1)×10−14. The extent of population inversion was investigated by measuring initial excited state and ground state atomic iodine concentrations, which gives the branching ratio [I*]/[I]. Values obtained are as follows: CH3I, 2.7; CF3I, 3.8; C2F5I, 2.7; i‐C3F7I, 3.2; n‐C4F9I, 1.8. Comparing both branching ratios an...
In search of optimum chest radiography techniques.
A nation-wide study of chest radiography in Sweden had previously revealed a large variation in the physical and technical factors involved, in particular the radiation dose. In this study the image quality could not be assessed unambiguously. The aim of the present study was to try to establish a correlation between visual grading of radiographs and physical and technical factors in order to find the optimum chest X-ray system. The physical and technical performance of 24 chest units was evaluated. Radiographs were taken of an anthropomorphic chest phantom supplied with test structures simulating various pathologies. Image quality was assessed by visual grading analysis of the radiographs. The physical and technical parameters of the units rated best were used to exemplify good radiographic practice. The results were in agreement with the recommendations issued by the Commission of the European Communities (CEC). It was also shown that low radiation dose is compatible with high-quality radiographic imaging of the chest.