Basic Study on Reactor Measurement & Control System by Laser

(1)Neutron Detection by LaserA new basic idea of this study is to apply nuclear pumping gas-laser including^3He gas to a neutron detector。As the lasing gas，at first，He-Ne gas was tried，that was given up because its low neutron sensitivity due to low^3 He gas pressure of about10Torr to be laser.Then，He-Ne-Ar gas was selected because it can contain about3atom of^3He gas when its lasing operation.Neutron irradiation experiments of^3He-Ne-Ar gas cells were made using the research reactor of YAYOI(Univ.of Tokyo)and JRR-4(JAERI)。Simulation calculations on the lasing process of this gas under neutron irradiation were made for both purposes to obtain the best gas composition and to make comparisons with experimental results of optical spectra.It is concluded that the lasing will occur over the neutron flux of 5*10^&lt；13&gt；n/cm^2·sec.(2)Reactor Control by LaserA new reactor control mechanism is studied to decreasing the^3He neutron absorption cross-section by half through the^3He nucleus spin orientations by laser.That is confirmed possible in KEK using He+Rb gas system irradiated 795 nm laser.Direct spin orientation by La-laser was also investigated.(3)Design of Reactor measurement&Control SystemAs a summary of this study，a design result on this system was proposed.

(1) Neutron Detection by LaserA new basic idea of this study is to apply nuclear pumping gas-laser including ^3He gas to a neutron detector. As the lasing gas, at first, He-Ne gas was tried, that was given up because its low neutron sensitivity due to low ^3He gas pressure of about 10 Torr to be laser. Then, He-Ne-Ar gas was selected because it can contain about 3 atom of ^3He gas when its lasing operation.Neutron irradiation experiments of ^3He-Ne-Ar gas cells were made using the research reactor of YAYOI (Univ.of Tokyo) and JRR-4 (JAERI). Simulation calculations on the lasing process of this gas under neutron irradiation were made for both purposes to obtain the best gas composition and to make comparisons with experimental results of optical spectra. It is concluded that the lasing will occur over the neutron flux of 5*10^<13>n/cm^2・sec.(2) Reactor Control by LaserA new reactor control mechanism is studied to decreasing the ^3He neutron absorption cross-section by half through the ^3He nucleus spin orientations by laser. That is confirmed possible in KEK using He+Rb gas system irradiated 795nm laser. Direct spin orientation by La-laser was also investigated.(3) Design of Reactor measurement & Control SystemAs a summary of this study, a design result on this system was proposed.