Method for assessing an alpha particle emission potential of A metallic material

Patent metadata

Field	Value
Publication number	US-8993978-B2
Application number	US-201313800115-A
Country	US
Kind code	B2
Filing date	Mar 13, 2013
Priority date	May 4, 2012
Publication date	Mar 31, 2015
Grant date	Mar 31, 2015

Abstract

A method for assessing an alpha particle emission potential of a metallic material. A metallic material is initially subjected to a secular equilibrium disruption process, such as melting and/or refining, to disrupt the secular equilibrium of the radioactive decay of one or more target parent isotopes in the material. A sample of the material is treated to diffuse target decay isotopes within the sample such that the measured alpha particle emission directly corresponds to the concentration or number of target decay isotope atoms within the entirety of the sample, enabling the concentration of target decay isotopes in the sample to be determined. The concentration of target parent isotopes in the material may then be determined from the concentration of target decay isotopes and time elapsed from the secular equilibrium disruption process, and may be used to determine a maximum alpha particle emission that the metallic material will exhibit.

First claim

What is claimed is:

1. A method for assessing an alpha particle emission potential of a metallic material, said method comprising the steps of:
detecting alpha particle emissions from a sample of the metallic material;
determining a concentration of a target parent isotope in the sample of the metallic material from the alpha particle emissions detected in said detecting step and a time which has elapsed between said detecting step and a prior secular equilibrium disruption process; and
determining a possible alpha emission of a target decay isotope of the target parent isotope from the determined concentration of the target parent isotope and a half-life of the target parent isotope.

2. The method of claim 1 , wherein the time which has elapsed is an elapsed time between said detecting step and a completion of a prior secular equilibrium disruption process.

3. The method of claim 1 , further comprising the additional steps, prior to said detecting step, of:
obtaining a sample of the metallic material; and
heating the sample to diffuse atoms of the target decay isotope within the sample until a uniform concentration of atoms of the target decay isotope is obtained throughout the sample.

4. The method of claim 1 , wherein the secular equilibrium disruption process is a process which removes contaminant components from the material.

5. The method of claim 1 , wherein the secular equilibrium disruption process comprises at least one process selected from a group consisting of melting, refining, and combinations of the foregoing.

6. The method of claim 1 , wherein the secular equilibrium disruption process comprises an electro-refining process.

7. The method of claim 1 , wherein the metallic material comprises tin, the target parent isotope is 210 Pb, and the target decay isotope is 210 Po.

8. The method of claim 1 , wherein said step of determining a possible alpha emission of a target decay isotope comprises determining a maximum possible alpha emission of the target decay isotope.

9. The method of claim 1 , wherein said step of determining a possible alpha emission of a target decay isotope comprises determining a possible alpha emission of the target decay isotope at at least 300 days from completion of the secular equilibrium disruption process.

10. A method for assessing an alpha particle emission potential of a metallic material, said method comprising the steps of:
subjecting a metallic material to a secular equilibrium disruption process;
obtaining a sample of the metallic material following said subjecting step;
detecting alpha particle emissions from the sample;
determining a concentration of a target parent isotope in the sample from the alpha particle emissions detected in said detecting step and an elapsed time between said subjecting step and said detecting step; and
determining a possible alpha emission of a target decay isotope of the target parent isotope from the determined concentration of the target parent isotope and a half-life of the target parent isotope.

11. The method of claim 10 , wherein the elapsed time between said subjecting step and said detecting step is an elapsed time between completion of said subjecting step and said detecting step.

12. The method of claim 10 , further comprising the additional step, after said obtaining step and prior to said detecting step, of heating the sample to diffuse atoms of the target decay isotope within the sample until a uniform concentration of atoms of the target decay isotope is obtained throughout the sample.

13. The method of claim 10 , wherein said subjecting step further comprises subjecting the metallic material to a process which removes contaminant components from the material.

14. The method of claim 10 , wherein said subjecting step further comprises subjecting the metallic material to at least one process selected from a group consisting of melting, refining, and combinations of the foregoing.

15. The method of claim 10 , wherein said subjecting step further comprises subjecting the metallic material to an electro-refining process.

16. The method of claim 10 , wherein the metallic material comprises tin, the target parent isotope is 210 Pb, and the target decay isotope is 210 Po.

17. The method of claim 10 , wherein said step of determining a possible alpha emission of a target decay isotope comprises determining a maximum possible alpha emission of the target decay isotope.

18. The method of claim 10 , wherein said step of determining a possible alpha emission of a target decay isotope comprises determining a possible alpha emission of the target decay isotope at at least 300 days from completion of the secular equilibrium disruption process.

19. The method of claim 10 , wherein said step of determining a possible alpha emission of a target decay isotope comprises determining a possible alpha emission of the target decay isotope at 828 days from completion of the secular equilibrium disruption process.

Assignees

• Honeywell Int Inc

Inventors

• Clark Brett M

Classifications

• G01T1/167 Primary

  Measuring radioactive content of objects, e.g. contamination (whole body counters G01T1/163) · CPC title

• G01T1/30

  Measuring half-life of a radioactive substance {(period meters for nuclear fission reactors G21C17/14)} · CPC title