Theα,nCross Section of Boron

The differential cross section for the ${\mathrm{B}}^{10,11}(\alpha ,n){\mathrm{N}}^{13,14}$ reactions was measured as a function of the alphaparticle energy up to an energy of 5.3 Mev. To determine this cross section, the number of neutrons emitted by boron under alpha-particle bombardment was measured by comparison with a calibrated $\mathrm{Ra}-\alpha -\mathrm{Be}$ source in a graphite column.