Pulsed neutron elemental on-line material analyzer

• US 6,438,189 B1
• Filed: 03/19/1999
• Issued: 08/20/2002
• Est. Priority Date: 07/09/1998
• Status: Expired due to Fees

• Current Assignee: Numat Incorporated
• Original Assignee: Numat Incorporated
• Inventors: Vourvopoulos, George
• Primary Examiner(s): Jordan, Charles T.
• Assistant Examiner(s): MATZ, DANIEL R
• Application Number:
  US09/273,428
• Publication Number:
  US 20020106047A1
• Time in Patent Office: 1,250 Days
• Field of Search: 376/158, 376/159, 376/160, 376/157
• US Class Current: 376/159
• CPC Class Codes: G01N 23/09 the radiation being neutrons
• CPC Class Codes: G01N 23/204 using neutrons
• CPC Class Codes: G01N 23/222 using neutron activation analysis [NAA]

Abstract

An on-line material analyzer which utilizes pulsed neutron generation in order to determine the composition of material flowing through the apparatus. The on-line elemental material analyzer is based on a pulsed neutron generator. The elements in the material interact with the fast and thermal neutrons produced from the pulsed generator. Spectra of gamma-rays produced from fast neutrons interacting with elements of the material are analyzed and stored separately from spectra produced from thermal neutron reactions. Measurements of neutron activation takes place separately from the above reactions and at a distance from the neutron generator. A primary passageway allows the material to flow through at a constant rate of speed and operators to provide data corresponding to fast and thermal neutron reactions. A secondary passageway meters the material to allow for neutron activation analysis. The apparatus also has the capability to determine the density of the flowed material. Finally, the apparatus continually utilizes a neutron detector in order to normalize the yield of the gamma ray detectors and thereby automatically calibrates and adjusts the spectra data for fluctuations in neutron generation.

Claims

1. An elemental on-line analyzer comprising:

a first material pathway through which material to be analyzed passes;

a second material pathway through which material to be analyzed passes;

a pivotable gate to divide a predetermined amount of material between said first material pathway and said second material pathway at predetermined times;

a pulsed neutron generator between said first pathway and said second pathway;

a plurality of gamma ray detectors in radiation detecting communication with material passing through said first and said second material pathways;

a data acquisition system operably connected to said gamma ray detectors;

wherein said on-line analyzer detects fast neutron reactions and thermal neutron reactions in said first material pathway for a first predetermined time period and neutron activation reactions in said second material pathway for a second time period.

2. The on-line material analyzer of claim 1 wherein said second material pathway is further comprised of a first gate at a predetermined position adjacent said pulsed neutron generator and a second gate at a predetermined position adjacent at least one of said plurality of gamma ray detectors.

3. The on-line material analyzer of claim 2 wherein said plurality of gamma ray detectors is comprised of a first gamma ray detector in said first material pathway to measure fast neutron reactions, a second and third gamma ray detector in said first material pathway to measure thermal neutron reactions, and a fourth gamma ray detector in said second material pathway to measure neutron activation reactions.

4. The on-line material analyzer of claim 3 wherein said data acquisition system obtains three spectra of gamma rays, a first spectrum from fast neutron reactions, a second spectrum from thermal neutron reactions and a third spectrum from neutron activation reactions.

5. The on-line material analyzer of claim 4 wherein said first spectrum is accumulated when said pulsed neutron pulse is on, said second spectrum accumulated between neutron pulses, and said third spectrum during said second predetermined time period in said second chute.

6. An elemental on-line material analyzer comprising:

a first continuously flowing material pathway through which material to be analyzed passes;

a second batch processing material pathway through which material to be analyzed passes;

a pivotable gate to divide a predetermined amount of material between said first material pathway and said second batch processing material pathway at predetermined times;

a pulsed neutron generator between said first pathway and said second pathway;

a first plurality of gamma ray detectors in said first material pathway and a second plurality of gamma ray detectors in said second material pathway;

a data acquisition system operably connected to said gamma ray detectors;

wherein said on-line analyzer detects fast neutron reactions and thermal neutron reactions in said first continuously flowing material pathway and neutron activation reactions in said second batch processing material pathway.

7. The material analyzer of claim 6 wherein at least one of said first plurality of gamma ray detectors measures fast neutron reactions during a neutron pulse of said generator, at least one of said first plurality of gamma ray detectors measures said thermal neutron reactions between pulses of said generator, and wherein said second plurality of gamma ray detectors measure said activation reactions in said second batch processing material pathway.

8. An elemental material on-line analyzer, comprising:

a first continuously flowing material pathway through which material to be analyzed passes;

a second batch processing material pathway through which material to be analyzed passes;

a pivotable gate to divide a predetermined amount of material between said first material pathway and said second batch processing material pathway at predetermined times;

a pulsed neutron generator adjacent said first continuously flowing material pathway and said second batch processing material pathway;

a first stop gate within said second batch processing material pathway adjacent and downstream of said pulsed neutron generator;

a first plurality of gamma ray detectors in said first material pathway and a second set of at least one gamma ray detector in said second material pathway;

a second stop gate within said second batch processing material pathway adjacent and downstream of said second set of at least one gamma ray detector;

a data acquisition system operably connected to said gamma ray detectors;

wherein said on-line analyzer detects fast neutron reactions and thermal neutron reactions in said first continuously flowing material pathway and neutron activation reactions in said second batch processing material pathway.

9. The on-line analyzer of claim 8 wherein said fast neutron reactions are measured during a pulse of said pulsed neutron generator, said thermal neutron reactions are measured between pulses of said pulsed neutron generator, and wherein material in said second material pathway is irradiated at said first stop gate simultaneously with said measurements of said thermal neutron reactions and said fast neutron reactions.

10. An elemental material on-line analyzer, comprising:

a first continuously flowing material pathway through which material to be analyzed passes;

a second batch processing material pathway through which material to be analyzed passes;

a pivotable gate to divide a predetermined amount of material between said first material pathway and the second batch processing material pathway at predetermined times;

a pulsed neutron generator adjacent said first continuously flowing material pathway and said second batch processing material pathway;

a first stop gate within said second batch processing material pathway adjacent said pulsed neutron generator;

a first plurality of gamma ray detectors in said first material pathway and a second set of at least one gamma ray detector in said second material pathway;

a second stop gate within said second batch processing material pathway adjacent said second set of at least one gamma ray detector;

a data acquisition system operably connected to said gamma ray detectors;

said one-line analyzer detects fast neutron reactions and thermal neutron reactions in said first continuously flowing material pathway and neutron activation reactions in said second batch processing material pathway, said fast neutron reactions measured during a pulse of said pulsed neutron generator, said material in said second material pathway irradiated at said first stop gate simultaneously with said measurements of said material neutron reactions and said fast neutron reactions.