Gamma rays interacting mainly with the counter wall produce small pulses which are registered in the low energy end of the pulse height distributions. Helium nuclei scattered at wide angles as well as the recoil nuclei of the other gases present in the detectors, also contributes to this part of the distributions. The gamma ray contribution to the pulse height distribution of 3He counter can extend almost up to the thermal neutron peak [10]. Under normal operating conditions neutrons and gamma rays are effectively distinguished from each other by rise time discrimination, since, typically, pulses originating from gamma rays have longer rise times. Spectra collected using gamma and beta rays show similar behavior in both detectors. They contribute to the low energy end of the pulse height distribution with the count number exponentially decreasing as channel number increases. Data collected with various shaping time constants were very well fitted (R2499:95%) with the function