The energies of recoil particles from (n, α) or (n, 2α) reactions of Li and B were investigated by solid state detector and gas phase electrodeposition as previously reported on228Th series. Nuclear reactor of UTR-Kinki was used as thermal neutron source. Particles from6Li (n, α) 3T and10B (n, α) 7Li were collected on a sheet of triacetate film by gas phase electrodeposition at atmospheric pressure. The film was etched with 6M-NaOH at 50°C. The tracks thus obtained were taken as photographs with a microscope (×600) . By counting the number of tracks on the film at various etching times, the energies of α-particles were evaluated according to the calibration curve of227Ac series. Among various peaks of track density, the two peaks having the evaluated values of 1.85 MeV for6Li and 1.48 MeV for10B agreed approximately with the theoretical values of 2.05 MeV and 1.47 MeV of α-particle energies for respective reactions.
Neutron flux and irradiation time should be accurately known in neutron activation analysis using very short lived nuclides in which conventional monitoring methods i.e., a comparator method, flux monitor method and so on cannot be used satisfactorily. Especially, fluctuation of neutron flux has not been corrected. We noted a change of reactor power at a pneumatic operation, and found out a new correction method for its correction in activation analysis. In our small nuclear reactor, TRIGA-II, the reactor power increased rapidly a few % when a pneumatic-operated capsule arrived at a core of the reactor, and decreased when the capsule left from the core. If the duration between these two changes of the reactor power is equal to the irradiation time, and that the reactor power is proportional to the neutron flux, we can regard an activity formation as a time integration of the reactor power. Then, the correction system was made of a reactor power meter, a V-F converter (voltage to frequency converter), a clock time, a counter, a microcomputer, electric circuits and so on. The signal of the reactor power during the irradiation was counted through the V-F converter, and was accumulated in a memory of the microcomputer. The neutron fluence was calculated in this microcomputer. This method was examined by means of activation of copper and selenium standard samples by 9-11 sec irradiation. The observed activity involved ±10% error. However, the error in the corrected activity was decreased to a few % using this correction method. As a result, we found that this method can be used to obtain accurate value for radionuclide formation.
In order to estimate the fallout amounts of transuranium elements, monthly deposits have been collected at Tokai, Ibaraki Prefecture, during the period from October 1978 to March 1980, and were analyzed both on241Am and239+240Pu also on major surface soil components, SiO2and Al2O3. Major soil matrices contents in the deposits suggested that 5.1 % of the observed239+240Pu deposition was contributed by resuspension from ground deposit with wind-blow, on the other hand, much greater contribution of 10.3 % of241Am was by the resuspension. Fallout amounts exclude resuspension of241Am and239+240Pu throughout the period were estimated to be 11.0 and 212 mBq/m2 (0.30 and 5.73 pCi/m2) respectively and annual values were 10.0 and 166 mBq/m2·y (0.27 and 4.49 pCi/m2·y), respectively in 1979. Activity ratios of241Am/239+240Pu changed widely. The average value of 0.066 was calculated from total amounts of each nuclides.
The undecapeptide, human glucagon (19-29), was prepared as immunogen for production of pancreatic glucagon-specific antisera by the conventional method for peptide synthesis, and a radioimmunoassay with use of antiserum raised against the synthetic undecapeptide was developed. The assay system was evaluated for the measurement of plasma immunoreactive glucagon.