Ionization and scintillation phenomena in liquid Ar, Kr and Xe excited by charged particles have been summarized. A review is given on. the recent progress made in the last 10 years as well as the basic understanding of theories on W-value and Fano factor. The additional ionization yield for Ar-Xe mixtures (which corresponds to Jesse effect in the gas phase) is explained in terms of the energy transfer from the Ar exciton to the Xe-dopant. The electric field effect on the scintillation intensity and the decay time measurments have been described. The electron multiplication and proportional scintillation in liquid Xe in high electric field have been also reviewed. After a brief consideration for the drift velocity of electrons in liquid Ar, Kr and Xe and their mixtures, application of these liquids to γ-ray detectors, position sensitive detectors and total absorption counters has been reviewed.
A review of basic properties, recent progresses on excitation technique and performance characteristics of excimer lasers is presented. Excimer lasers are charactererized as high-power high efficiency lasers in the UV and VUV wavelength region. Excimer lasers are compared with the other high power lasers and UV and VUV lasers in terms of the basic parameters, efficiency and wavelength. Detailed kinetic models are presented for Xe2, KrF and XeF lasers. Some technical progresses are described on excitation methods including E-beam excitation, E-beam sustained discharge, UV-preionized discharge and Blumlein-drive discharge. Experi-mental results on the characteristics of laser are summarized with emphasis on rare-gas halide lasers. Finally the application of excimer lasers in spectroscopy, pumping of dye lasers, nonlinear optics, isotope enrichment and laser fusion are also discussed briefly.
Attempts to improve the efficiency of the Blumlein-type UV-nitrogen laser to a maximum were made by optimizing a number of both the structural and operational parameters. A 30 cm length laser with demountable and low-inductance structure was constructed, and its output characteristics were examined under a variety of conditions of discharge electrode spacing and structure, character and position of the driving switch, and gas pressure. As a result, the highest efficiency of 0.5% was achieved at a power level of 600 kW for pure N2 gas. With N2-SF6 gas mixture, a further increase of efficiency by a factor of 1. 6 was found. Output characteristics of a scaled-up laser of 90 cm length were also measured, and various causes of efficiency reduction were examined. Among these, we found that the laser output energy (W) and the charging capacitor. length (l) are connected by the relation W∝_??_.
A thermoelectric resistance thermometer is a grafted thermometer which is composed of a thermocouple and a thermometric resistance bulb in series and a constant current device. A constant current determined by the characteristics of both the thermocouple and the thermometric resistance bulb flows through the circuit, and the potential difference between two fixed points in the circuit is measured. It is proved theoretically that the measured potential difference gives the temperature to be determined. Experiments are made with two typical circuits of an operational amplifier and a Wheatstone-bridge type, respectively. Results show that the outputs of the trial thermoelectric resistance thermometer are fairly in good accordance with the e. m. f from the thermoelectric thermometer of the reference temperature of 0°C.
The adsorption of the CO-W system has been studied at 300 K, 200 K and 80 K by means of the FEM method. A model which assumes seven types of intrinsic sites on the semispherical surface of a b. c. c. crystal is used to interpret the change of FEM patterns which appeared during the adsorption at 300K. This interpretation shows that the CO-adsorbed layer at the maximum coverage at 300 K is related to an occupation of seven types of adsorbed CO originating from the above seven- types of intrinsic sites. For the adsorption at 200 K and 80 K similar discus-sion is considered possible. From this point of view three patterns at the maximum coverage at the above three temperatures are compared, and it is shown that the pseudo-clean pattern appears when the population of all the above seven types of CO depends entirely on the surface structure of clean tungsten tips.