The method of high sensitivity measurement of argon in the air is described. The argon at a certain pressure was sealed in a cylindrical glass vessel, and radioactivated with neutrons generated with an accelerator. The radioactivity was measured wity a Ge detector. The detection efficiency was calculated by Monte Carlo method. By converting the41Ar activity to the concentration of argon in the air, it was possible to measure with the sensitivity about 56 times as high as the case of directly radioactivating the air.
The measurement of222Rn in water, ‘liquid scintillation counting of radon extracted with toluene’, was improved. It was found in the previous calculation method that radon concentration had been determined low about 2%. The equation in the previous calculation was derived by the underestimation of radon solubility in toluene. The applicable calculation of radon concentration was proposed using mole fraction form and thermodynamic solubility equations.
The rate of seedling growth of the semidwarf mutant cultivar Reimei and the dwarf mutant line, Fukei 71 were found to be much faster than their original cultivar Fujiminori. Such rapid early growth of the dwarf and semidwarf mutants was significantly inhibited by the treatment with the ethylene synthesis inhibitor, aminoethoxyvinylglycine (AVG) . For example, with 25μM of AVG treatment the elongation was inhibited by 36% and 41% during the growth of Reimei and Fukei 71 seedlings, respectively, as compared with 13% for that of Fujiminori. Gas chromatography showed that ethylene production in Reimei and Fukei 71 were about 2.5 and 7.1-fold higher than that of Fujiminori, respectively. It was suggested that the stimulation of the growth in dwarf and semidwarf mutants might be derived from the increased ethylene production.
The parallel interface was developed for the purpose of digital data on-line transfer from ionization chamber connected vibrating reed electrometer to the personal computer (PC) . This system is applicable for the electrometer that has the digital data output and the control function of BCD code, and the measurement procedure can be controlled by the software of PC. Practical applications of this simple measurement system have been demonstrated for three experiments. One is the routine tritium concentration monitoring in air at the tritium laboratory. Second is a special tritium monitoring in a case of the tritium target exchange work for the D-T neutron generator. The third application is shown on the tritium release-rate measurement from the tritium adsorbed SS materials, where tritium water vapor was continuously monitored for 100 minutes, and the least square analysis of the obtained data was also made in the same PC.