Development of monoenergetic energy neutron generating target for irradiation of biological materials using an accelerator and its dosimetry

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This study included that (1) development of monoenergetic energy neutron generating system for use in radiobiology study (especially development of neutron generating targets), (2) dosimetry study of the neutrons.The actual studies were (a) development and confirmation of a technique to evaporate lithium metal on copper plate and to use as thin lithium target of about 10 mum thickness, (b) measurement of neutron dose rate generating due to (n, p) reaction using twin chamber method, (c) measurement of quality and spectra of the neutrons using LET counters and Hc-3 neutron spectrometer, respectively, (d) measurement of stableness of the target (possible irradiation time) and (e) test irradiation of mice to check total irradiation system. As for the measurement (b) we used a tissue equivalent chamber for determination of total neutron plus gamma-ray doses, and graphite chamber and GM counter for determination of gamma-ray dose.In the study of (a) we used a evaporation apparatus and made about 10mum thick lithium target. Now we can make them routinely. As for (b) we determined dose rates at different angles and distances.The dose rate more than 10 cGy/min is available and contamination of gamma rays are less than 5%. In(c)energy spread of monoenergy neutrons are 5-9%. We found the LET spectrum reproduced the other measurements. In (b), we found irradiation for about 10 hours are possible. In (e), we checked the total irradiation system was working reasonably.In conclusion we confirmed this neutron irradiation system for radiobiology study and successfully completed this study. After this, it will be neccessary that development of the other types of targets and set up of the PIXE system.