[A new correction method for radionuclide formation in neutron activation analysis using a reactor power meter coupled with a microcomputer].
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 irradiations. 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.
D000201:Activation Analysis / Q000379:methods*; D003201:Computers; D003300:Copper; D008838:Microcomputers; D009501:Neutron Activation Analysis / Q000379:methods*; D009688:Nuclear Reactors; D011851:Radioactivity; D011868:Radioisotopes / Q000032:analysis*; D012643:Selenium; D013997:Time Factors
D011868:Radioisotopes; D003300:Copper; D012643:Selenium