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Six kinds of radioisotopes were used to measure cross sections of the 9Be(γ, n) reaction near its threshold. The results obtained were 0.88 ± 0.16, 1.33 ± 0.24, 1.10 ± 0.20, 0.73 ± 0.13, 0.47 ± 0.09, and 0.18 ± 0.04 mb at 1674.7, 1705.2, 1724.9, 1778.9, 1836.0, and 2167.6 keV, respectively. The cross sections measured show a sharp peak near the threshold, and its width is narrower than that observed by Jakobson with Bremsstrahlung X-rays. Comparison of the present results with theories based on the valence neutron model indicates that the agreement is only qualitative.

Using 1576-keV γ-rays from 142Pr, the cross section of the direct three-body breakup of 9Be was measured and found to be (4.0 ± 1.8) × 10−1 μb. This result is in approximate agreement with Salyers' theoretical estimate based upon a cluster model of 9Be.

A method for the measurement of depth profiles of tritium in solids has been developed in which the 3H(d,n)4He reaction is used. This method is nondestructive with relatively high depth resolution in the surface region of the solids. The validity of the present method has been supported by the examination of the depth profile measured for a tritium target as is used for a neutron source.

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