High resolution measurement of 3He depth profile

In investigation into the behaviours of He atoms in the first wall materials of controlled thermonuclear reactor (C.T.R.), 3He depth profiles in metals implanted with a particle accelerator have been measured in terms of 3He(d, α)H reaction. In order to improve the depth resolution and to obtain a large observing solid angle simultaneously in beam experiments, first a 5 kilogauss magnetic deflector which deflects secondary electrons and forward scattered deuterons is put in front of the solid state detector. The depth resolution of 3He profile in Ta and Nb metals implanted at energy of 500 keV is 135 A and 166 A, respectively, and the observing solid angle is 5 x 10-4 Sr. Then the magnetic spectrograph is constructed combining a 90 degree deflecting magnet and a position sensitive solid state detector (P.S.D.). It is estimated that the resolving power of 3He depth profile in Ta is about 100A, and that the observing solid angle is about 5 x 10-4 Sr. (author)