Search for the 2.37-MeV γ ray from the 94Zr(n,n'γ) reaction

A search has been made for a 2.37-MeV γ ray using the ⁹⁴Zr(n,n′γ) reaction at an incident neutron energy of 5 MeV in an attempt to observe the 2.37-MeV (2⁺) level seen in ⁹²Zr(t,p)⁹⁴Zr and ⁹⁶Zr(p,t)⁹⁴Zr reaction studies and predicted in an earlier ⁹⁴Zr(n,n′γγ) experiment. This γ ray has not been observed. Other possible decay modes of the 2.37-MeV (2⁺) level have been looked for and ruled out except for the unlikely case of the level decaying to several levels in such a way that no one level receives an appreciable amount of the decay. As a result we are left with the puzzle that the ⁹⁴Zr(n,n′γ)⁹⁴Zr reaction excites a 4⁺ level at 2.336 MeV not seen in the ⁹²Zr(t,p)⁹⁴Zr and ⁹⁶Zr(p,t)⁹⁴Zr reactions. The (t,p) and (p,t) reactions excite a 2⁺ level at 2.37 MeV not observed in the (n,n′γ) reaction.