Studies of Neutron Thermalization in H₂O by the Pulsed Source and “Non 1/ν” Absorbers Method

A new method for measuring neutron thermalizaton parameters that was proposed on theoretical grounds is tested experimentally for H₂O. The characteristic thermalization parameters in the present formulation are where are Laguerre polynomials of order unity and degree i and T is the temperature of the system expressed in energy units. The present experimental results for H₂O can be described using one parameter. The result is γ₁₁ = (0.210 ^± 0.026)cm^-1 for 23 C. The value of this parameter as derived from diffusion-cooling measurements lies in the range of 0.4cm^-1 to 0.8cm^-1. A possible explanation for this discrepancy is given. The value of γ₁₁ as calculated on the basis of Nelkin's model is about four times higher than the present result.