Be is often used as the neutron gun to supply neutrons to initiate nuclear reactions, particularly nuclear chain reactions. I always presumed the nucleus of lighter elements to be more stable than the heavier ones. Be with an atomic number of 4, meaning 4 protons, it is twice that of a helium nucleus. The helium nucleus is the same as an alpha particle, and is regarded as the most stable light nucleus.
Being that we can think of Be as two helium nuclei fused together, one would presume that the Be nucleus would be very hesitant to change its structure and give up neutrons. But this is what happens when it is struck with an alpha particle. Why is this so? I read that it has a neutron spin of 3/2. I don't yet understand the neutron spin property, but maybe this could explain it.