Granted Patent B2

US 12,633,380 · App. 18/363,345 · Granted May 19, 2026

Inventors: Steven Wayne Pauly (Knoxville, TN); William Mark Richardson (Knoxville, TN); Phillip John Boone (Lenoir City, TN)

Assignee: Rapiscan Holdings, Inc.

G16C20/10

Abstract

Claims (28)

1 . A radiation portal monitor comprising:

a processing system; and,

a plurality of detectors in data communication with the processing system wherein the processing system is configured to determine if radiation spectra comprises radiation corresponding to naturally occurring radiation material (NORM) sources by:

generating a database of training spectra, each of the training spectra in the database representing a NORM material;

obtaining the radiation spectra;

normalizing the obtained radiation spectra by using one or more predefined normalization techniques;

energy scaling the normalized radiation spectra by using one or more energy scaling techniques;

fitting the normalized, scaled radiation spectra to at least a portion of the training spectra in the database;

determining a residual generated from fitting the normalized, scaled radiation spectra with respect to said portion of the training spectra; and

identifying the normalized, scaled radiation spectra as representing a NORM material based on the residual and a threshold value.

2 . The radiation portal monitor of claim 1 wherein the normalized, scaled radiation spectra is determined as representing a NORM material when the residual is less than the threshold value.

3 . The radiation portal monitor of claim 1 wherein the processor is further configured to identify the normalized, scaled radiation spectra as belonging to an ‘other’ category when the residual is greater than the threshold value.

4 . The radiation portal monitor of claim 1 wherein the processor is configured to determine the threshold value empirically based on the training spectra and the residual of fitting the normalized scaled radiation spectra with a class of the training spectra.

5 . The radiation portal monitor of claim 1 wherein obtaining the radiation spectra comprises gathering energy spectra radiated by an object being inspected in the radiation portal monitor by using one or more of the plurality of detectors.

6 . The radiation portal monitor of claim 1 wherein energy scaling the normalized radiation spectra comprises applying predefined weights to the obtained radiation spectra to obtain a weighted matrix of said obtained radiation spectra.

7 . The radiation portal monitor of claim 1 further comprising Optimal Linear Associative Memory (OLAM) based artificial neural networks trained by one or more of said training spectra.

8 . The radiation portal monitor of claim 1 further comprising an Optimal Linear Associative Memory (OLAM) neural network implemented within a field-programmable gate array (FPGA) integrated circuit, wherein the OLAM neural network implemented within the FPGA is configured to determine when the radiation spectra comprises radiation corresponding to NORM materials.

9 . The radiation portal monitor of claim 1 wherein the normalized, scaled radiation spectra is fitted to each of the training spectra in the database in a sequential fashion.

10 . The radiation portal monitor of claim 1 wherein the NORM material is at least one of: Ra-226, Th-232/Tl-208, K-40, and U-238.

11 . The radiation portal monitor of claim 5 wherein the plurality of detectors are large-area low-resolution radiation detectors.

12 . The radiation portal monitor of claim 5 wherein the plurality of detectors are polyvinyltoluene (PVT) detectors.

13 . The radiation portal monitor of claim 5 wherein the plurality of detectors are gamma radiation detectors.

14 . The radiation portal monitor of claim 5 wherein the radiation portal does not include a radiation source.

15 . The radiation portal monitor of claim 5 wherein the radiation portal is a passive radiation portal monitor (RPM) used to detect presence of ionizing radiation sources passing through the RPM.

16 . The radiation portal monitor of claim 15 wherein the RPM comprises a plurality of panels, wherein opposing ones of the plurality of panels are spaced to enable a cargo container to pass between said opposing ones of the plurality of panels.

17 . The radiation portal monitor of claim 16 wherein each of the plurality of panels comprises a radiation detector.

18 . The radiation portal monitor of claim 6 wherein the one or more energy scaling techniques add more weight to higher energies in the normalized radiation spectra for aiding in determination of NORM materials.

19 . The radiation portal monitor of claim 7 wherein the training spectra for the OLAM based artificial neural networks comprise one spectrum from each isotope of the NORM material.

Assignments (2)

Continuity (2)

References Cited (400)