Helium three is an extremely rare but stable isotope of helium made up of two protons and only one neutron.Because ⁴He is so tightly bound, considerable energy is given off when ³He absorbs a neutron. This makes ³He a very good neutron detector. The nuclear reaction involved is n + ³He → ⁴He + γ. Neutron detection is a vital aspect of homeland security in the twenty first century, since nuclear devices inevitably give off very-low-energy neutrons that easily leak out of almost any container. What is the energy of the γ-ray given off when a thermal neutron (with energy ∼ 1/40 eV) is absorbed by a ³He nucleus?