抄録
This short note describes briefly on a cryostat of the polarized hydrogen target by means of so-called dynamic nuclear orientation, which was constructed for proton-proton scattering experiment with the 50MeV synchrocyclotron at Institute for Nuclear Study, University of Tokyo. The entire system consisted of a liquid helium dewar at the top and a cryostat part involving a target cavity. Liquid helium stored in the dewar was guided downwards through a thin pipe and spurted out continuously at the target cavity. Temperature of the target was easily adjusted by changing flow of liquid helium with a needle valve. The lowest temperature obtained was about 1.2°K and 1.5°K with and without the microwave power (about 75mW, 70kMc/s). The average helium loss was approximately 1.2l/hour., not involving losses during transfer of liquid helium to the dewar from outside. Average polarization obtained through 300 hours' experimental run was about 30%.
