The purpose of the study described in this paper is to make clear the fundamental characteristics of dual energy gamma-ray transmission techniques and to formulate theoretical system useful for optimum design of an apparatus. Since the early 1970's, a number of papers on the dual energy gamma-ray transmission techniques have been reported. In some papers, the above mentioned aspects were described. The authors have attempted to improve these descriptions by evaluating statistical errors, constant errors and proportional errors, and have formulated theoretical equations generally applicable to the dual energy gammaray transmission techniques. The key quantity in the theoretical system is R value, that is, a ratio of mass attenuation coefficients for low and high energy gamma-rays. The theoretical equations are represented by using the R value. Among the equations obtained, the relationship between δR/R (relative error of R value) and ppi (μ: mass attenuation coefficient, p: density of sample, l: thickness of sample) makes it possible to estimate the precision attainable in the measurement. Furthermore, the obtained equations give a suitable choice of gammaray energy pair which is important in the design. To prove the usefulness of the theoretical equations, the authors carried out the measure-ment of pottery, metal and slurry concentration using133Ba, 137Cs and22Na, and obtained the results expected.
Distribution and uptake rate of42KCl solution when applied as foliar fertilizer were measured.42 KCl tracer solution was prepared by the milking method from42Ar-42K generator. The total uptake ratio of42K was about 20% in 24 h. To enhance the uptake rate and amount, leaf moisturing method was effective, which raised the uptake ratio three times higher. When the solution was applied at the back side of the leaf, the absorbed amount was 10 to 20% higher than that amount applied at the surface side of the leaf. The amount of42K uptake measured in this report suggests that the foliar fertilization of K can be the econo-mical way of fertilization in Brazil.
Silicon and phosphorus contents in polished and unpolished rice planted on a district of high incidence of amyotrophic lateral sclerosis (ALS) have been determined by neutron activation and X-ray fluorescence methods, and compared with those from control areas. In the neutron activation analysis, β-ray spectra of32P produced by the31P (n, γ) 32P reaction on polished and unpolished rice were measured with a low background β-ray spectrometer. In the X-ray fluorescence analysis, characteristic X-rays were analyzed with a wavelength dispersive X-ray fluorescence spectrometer. Silicon contents in polished and unpolished rice from the ALS area are 42 μg·g-1and 370 μg·g-1, respectively, and the corresponding phosphorus contents are 1210μg·g-1, and 3 370μg·g-1, respectively. The data for ALS area are equal to those for the control area within standard deviation.
CA 19-9 epitope (s) on carcinoembryonic antigen (CEA) was studied by a method designated the hybrid immunoradiometric-assay (hybrid IRMA) using solid phase CEA antibody as a capture of CEA molecule and radio-labeled NS 19-9 antibody as a detector. The radioactivities of the hybrid IRMA of respective sera with certain cancers differed from that of normal sera. The specific radioactivities of hybrid IRMA were not disappeared by washing with the reaction mixture containing Triton X-100 as a detergent. Treatments of the sample with neuraminidase or periodate diminished the specific bound radioactivities, like as a CA 19-9 antigen. Furthermore, the treatment of CEAs by PI-PLC had no effect to the radioactivities. Taken together, it was suggested that CEA sugar moieties contain CA 19-9 like epitope (s) .
A lead-shielding was constructed for a welltype Ge detector to utilize low-level r spectrometry. Background counting rate was investigated under lead thickness of 5-25 cm. It has been confirmed that selection of low activity materials for the construction of the detector has advantage to reduce the contribution of background deu to natural radioactivities. N2gas was helpful to reduce the contribution of atmospheric radon daughters especially during ofd ventilation period.