This detector takes advantage of the 10B(n,a)
reaction. Boron is present as a gaseous BF3 and the system is rub as a
proportional counter.
Most of the (n,a) reactions do not leave
the product 7Li in its ground state, but in its first
excited state. This will subsequently de-excite down to the ground
state, in most cases emitting a 0.482 MeV gamma.
Therefore expect to see two separate peaks in a pulse height
spectrum.
Within the spectrum produced things to take into consideration are: