Perfect noise pulse rejection is essential for the reliable detection of low-level neutrons using3He proportional counters. Inevitable noise pulses are due to external noises, which could completely be discriminated increasing the height of signal pulses to be larger than the maximum noise pulse height by increasing the gas gain of the counters. Usual detection criterion based on the Gaussian statistics cannot be applied to ultra lowlevel counting where background counts are less than about 20. Another detection criterion based on the Piosson statistics is proposed, which coincides with the former in the extreme of large background counts. The proposed criterion is effectively applicable to the detection of burst neutron emission from “cold nuclear fusion”.
With the help of reactor neutron activation analysis investigations of the trace elements such as copper, manganese, zinc, seleeium, nickel, cadmium and mercury have been performed purposing to settle the problems of distinction between healthy persons and patients sffering from diabetes. In this technique, Ke, 0-method as a new standardization technique, were applied, in which, the deviation of the 1/E1+αepithermal neutron flux distributions from 1/E law, true coincidence effects of cascade γ-rays, and the efficiency of the Ge-detector were taken into consideration. Short lived nuclides were determined by a short activation with the help of a pneumatic irradiation facility and automatic correction of dead time and decay. The medium and long lived nuclides were determined after 48 h irradiation and ten days cooling. The patients head-hair samples showed a significant differences in the Cu, Zn, Se, and Hg. The result indicates that early diagnosis by means of trace elements determination could be possible.
Thorium in a Thorotrast patient's liver was determined by a new analytical technique, ICP MS. In the sample dissolution semi-fusion method with NH4HSO4as a flux was used. The resultant cake was dissolved in aqua regia and diluted for the ICP-MS measurement. The obtained result showed good accordance with that by α-spectrometry, showing the present combination of the dissolution and ICP-MS is quite suitable for the determination of Th in the Thorotrast liver.
Pharmacia HA 50R (Pharmacia) which enables direct measurement of serum hyaluronan concentration is evaluated for its convenience and accuracy. In this kit, HABP which has specific affinity for hyaluronan is radiolabelled with125I as ligand assay is performed as radiometric assay. Intra and inter assay precision, linearity and recovery test give favorable results. It is confirmed that this kit is convenient and useful for measurement of serum hyaluronan concentration.