TY - JOUR T1 - Secondary $ \gamma $-Rays Produced by $ \beta $-Rays JF - Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character (1905-1934) VL - 85 IS - 576 SP - 131 EP - 139 PY - 1911/04/11/ UR - http://dx.doi.org/10.1098/rspa.1911.0027 M3 - doi:10.1098/rspa.1911.0027 AU - Gray, J. ER -