TRANSMITTANCE MEASUREMENTS OF COLD NEUTRONS FOR SOME MATERIALS BY MEANS OF NEUTRON RADIOGRAPHY

We examined cold neutron radiography (CNR) to determine its characteri stics with respect to the ability to obtain the quantitative measureme nts. In order to; describe the complicated transmission phenomena in C NR, a thickness dependent attenuation coefficient mu(t) is introduced instead of an average attenuation coefficient, A simple function using a linear approximation model to mu(t) is proposed to express transmis sion curves in CNR. This function agreed well with the experimental da ta for materials having deep and shallow Bragg cutoffs and for a 1/v d ependent material, Thus, the linear approximation to mu(t) is effectiv e for describing the transmission phenomena in CNR.