Petroleum stream analyzer

A petroleum stream analyzer includes a test cell having a petroleum stream, or portion thereof, flowing through it. A neutron source bombards the petroleum stream in the test cell with fast neutrons, which are slowed down and thereafter engaged in thermal neutron capture reaction with materials in the petroleum stream. Gamma ray apparatus including a gamma ray detector provides an energy spectra of gamma rays from the materials in response to the capture of the thermal neutrons by the materials in the petroleum stream. Shielding material separates the neutron source from the gamma ray detector and a housing located within the test cell houses the neutron source, the gamma ray detector and the shielding material in a manner so that a longitudinal axis of the housing, which is substantially aligned with the axial flow of the petroleum stream in the test cell, passes through the neutron source, the shielding material and the gamma ray detector. The analyzer also includes apparatus which derive a measure of a characteristic of the petroleum stream in accordance with the obtained gamma ray energy spectra of the materials in the petroleum stream