Annihilation radiation analysis

摘要

An apparatus and method for quantitatively measuring the concentration of a first element or group of elements having substantially similar atomic numbers in a matrix comprising other elements having substantially different atomic numbers to that or those of said first element or group of elements is diclosed. The apparatus comprises (i) a source yielding gamma -rays, of sufficient energy for pair production; (ii) detecting means being associated with said source and being capable of detecting 0,511 MeV annihilation radiation; (iii) first measuring means for making a measurement of or proportional to bulk density; (iv) shielding means interposed between said source and said detecting means thereby reducing the intensity of direct source gamma -rays impinging on said detecting means; and (v) calculating means associated with the outputs of said detecting means and said measuring means to calculated said concentration; and wherein said first measuring means is located so as to make said measurement of or proportional to bulk density over substantially the same volume of said matrix as that in which said annihilation radiation originates.