Intelligent automatic gain stabilization for radiation detection instrument
AssigneeHalliburton Company
InventorsRonnie J. Buchanan, Gilbert H. Forehand, Timothy D. Rice
Life of this patent
Estimating the term…
Abstract
An intelligent automatic gain stabilization method and apparatus for a radiation detection instrument automatically locate the position of a predetermined characteristic within an energy spectrum, automatically determine whether the characteristic is properly located, and automatically provide gain adjustment to the output of the radiation detection instrument to maintain measurement accuracy of the system.
Claims22
A method of stabilizing the output of a radiation detection instrument to provide consistent energy spectra with a predetermined peak at a predetermined energy level within the spectra, said method comprising:
- collecting an energy spectrum using the radiation detection instrument;
- testing the collected spectrum against a predetermined rule set to determine automatically both where the predetermined peak is in the collected spectrum and whether the located predetermined peak is at the predetermined energy level in the collected spectrum;
- and
- adjusting the output of the radiation detection instrument, in response to testing the collected spectrum, so that the predetermined peak of at least a subsequently collected spectrum is at the predetermined energy level within the subsequently collected spectrum.
An apparatus for stabilizing the output of a radiation detection instrument which includes a radiation detector assembly, said apparatus comprising:
- a variable gain amplifier for receiving output from the radiation detector assembly;
- and a programmed digital computer for receiving input responsive to output from the radiation detector assembly and for providing adjustment control to said variable gain amplifier, said programmed computer including:
- means for defining storage bins in said computer;
- means for defining one of the storage bins as a predetermined bin where data representing a predetermined radiation interaction event energy sensed by the radiation detector assembly should be stored;
- means for collecting respective data in response to output from the radiation detector assembly and for storing the collected data in respective bins;
- means for analyzing selected groups of bins for determining which group of bins includes a bin containing data representing the predetermined radiation interaction event energy and for determining whether said determined group includes the predetermined bin;
- means for generating a course adjustment signal for controlling said variable gain amplifier in response to said means for analyzing determining said determined group does not include the predetermined bin;
- and
- means for generating a fine adjustment signal for controlling said variable gain amplifier in response to said means for analyzing determining said determined group does include the predetermined bin.
A method of stabilizing the output of a radiation detection instrument to provide output electric pulses consistently representing respective radiation energies deposited in a detector of the instrument for respective individual radiation interaction events, said method comprising:
- (a) automatically determining which of a sample of the output electric pulses are to represent a predetermined radiation energy and determining whether these output electric pulses actually designate the predetermined radiation energy;
- and
- (b) automatically adjusting the output of the radiation detection instrument in response to determining that the sampled output electric pulses that are to represent the predetermined radiation energy do not designate the predetermined radiation energy;
- wherein step (a) includes:
- (a1) converting respective sampled electric pulses to respective counts;
- (a2) generating respective digital counts of the numbers of counts from step (a1) having the same values and storing each digital count as a respective identifiable bin in a computer memory;
- (a3) determining whether the predetermined radiation energy could be represented by a digital count within a selected group of the bins, including computing a sum of the digital counts in the selected group of bins and computing a sum of the digital counts for a plurality of groups of the bins;
- and
- (a4) for a selected group of bins determined in step (a3) to be a candidate group by including a digital count that could represent the predetermined radiation energy, determining whether the candidate group actually includes the digital count that represents the predetermined radiation energy, including comparing a sum of the digital counts from the bins in the candidate group to a sum of the digital counts from the bins in another selected group of bins.
A method of automatically stabilizing the output of a radiation detection instrument continually throughout actual use of the instrument, to provide output electric pulses consistently representing respective radiation energies deposited in a detector of the instrument for respective individual radiation interaction events, said method comprising:
- (a) automatically determining which of a sample of the output electric pulses are to represent a predetermined radiation energy and automatically determining whether these output electric pulses actually designate the predetermined radiation energy;
- (b) automatically adjusting the output of the radiation detection instrument in response to determining that the sampled output electric pulses that are to represent the predetermined radiation energy do not designate the predetermined radiation energy regardless of the offset between the radiation energy represented by said output electric pulses and the predetermined radiation energy;
- and
- (c) automatically repeating said steps (a) and (b) throughout actual use of the radiation detection instrument.
Dependencies are inferred from the claim text.