Abstract: An apparatus and method for determining the amount of nitrogen in an object. A support means is provided for supporting the object, and at least one gamma ray beam is disposed on one side of the support for producing a beam of about 9.2 MeV gamma rays and in sufficient intensity to cause measurable resonant absorption by .sup.14 N in the nitrogenous compounds. A directing device is disposed between the gamma ray beam and the support for directing the gamma ray beam to the support at a predetermined angle, such that the gamma ray beam forms a path which encounters at least a portion of the object when disposed on the support. An array of gamma ray detectors are disposed on an opposite side of the support for detecting gamma rays of about 9.2 MeV transmitted through the object at both resonant and non-resonant angles.