| Abstrakt: |
The theory of the interaction of gamma rays with a single crystal of sodium iodide is described and a comparison made between the pulse height distributions, calculated on the basis of primary interactions only, together with the broadening due to the statistics of light production and electron multiplication, and the experimentally measured distributions. The differences are qualitatively accounted for on the basis of secondary interactions, bremsstrahlung, and wall effects. The absolute efficiency of a scintillation counter, calculated from the size and volume and energy corresponding to the bias level of the counting system, has been used to compute the intensity of gamma radiation from a standardized source of Co60and from the reaction Li7(p, γ)Be8, the yield of which was known from previous work. Good agreement was obtained after allowance was made, experimentally, for the secondary interactions. |
