Patent ID: 6051830
Filing Date: 2000-04-18
Classification: G01T,G01V

Abstract:
A method for calibrating a logging tool that is exposed to an external energy spectrum, comprising the steps of:(a) providing a stabilization source that emits a stabilization signal having a known energy value;(b) providing a receiver that receives a total spectrum that comprises the sum of the external energy spectrum and the received stabilization signal;(c) adjusting the gain of the tool so that the received stabilization signal has said known energy value, by the steps of:(ci) ensuring that the received stabilization signal is within a preferred range of said known energy value;(cii) calculating a value D.sub.n that is proportional to a derivative of the spectrum at the stabilization peak energy, where n is the order of the derivative and is odd;(ciii) adjusting the gain of the tool on the basis of the value of D.sub.n.