Gamma ray flaw detection system

Claim 1

In a system for non-destructive examination of a test object by irradiation thereof from a monoenergetic source emitting a collimated beam of radiation and detection of scattered radiation emerging from the irradiated test object within a measurement field to provide scattered radiation density distribution profiles of the field from measurement of energy levels therein, a method of analyzing the detection of flaws in said irradiated test object, including the steps of: comparing the radiation density distribution profiles with a reference profile corresponding to measured energy levels of scattered radiation emerging from an irradiated flawless object to provide differential spectra of the field; determining spatial relationships of the measured energy levels in the field relative to said beam of radiation; and extracting location and size data of the flaws in the test object from the differential spectra by data transformation thereof in accordance with said determined spatial relationships, said radiation density distribution profiles being formed by accumulation of data on the measured energy levels from which data the reference profile is subtracted during said step of comparing to establish the differential spectra, said spatial relationships being determined by correlation of the measured energy levels and scattering angles between the beam of radiation and lines extending therefrom at flaw locations to a common radiation detection point, said step of extracting the size data of the flaws including measuring the areas under pulse portions of the differential spectra respectively corresponding to peak values of the measured energy levels, said measured areas being substantially proportional to the size of the flaws.