Given , KE = 150 ev, `m_(n) = 1.675 xx10^(-27)` kg
`lambda = h/(sqrt(2m_(n)KE))= (6.63 xx10^(-34))/(2xx1.675 xx10^(-27) xx 150 xx 1.6 xx10^(-19)) = 2.33 xx10^(-12) ` m
The interatomic spacing is ` 10^(-10)` m , which is greater than this wavelength , So neutron beam of 150 eV is not suitable for diffraction experiment .