U.S. patent application number 11/724052 was filed with the patent office on 2007-12-06 for miniature multinuclide detection system and methods.
Invention is credited to Andrew F. Carpe, Charles A. Gentile, Stephen W. Langish.
Application Number | 20070278415 11/724052 |
Document ID | / |
Family ID | 38235572 |
Filed Date | 2007-12-06 |
United States Patent
Application |
20070278415 |
Kind Code |
A1 |
Gentile; Charles A. ; et
al. |
December 6, 2007 |
Miniature multinuclide detection system and methods
Abstract
The present invention is directed toward an apparatus and
methods for detection and identification of target radionuclides
and threatening radionuclides that may be present in a sample
volume. One aspect of the invention discloses a digital
computational apparatus that determines similarity or identity to a
target radionuclide or a threatening radionuclide. In another
aspect, the invention discloses a high throughput apparatus for
detection of a target radionuclide in a sample volume, or for
identifying a target radionuclide present in a sample volume, or
both, that includes a detecting means, an analyzing means, and an
identifying means. In a further aspect the invention discloses a
high throughput apparatus for communicating the presence of a
target radionuclide in a sample volume, the identity of a target
radionuclide in a sample volume, or both to appropriate personnel.
In yet another aspect, the invention provides a high throughput
apparatus for warning of the presence and/or the identity of a
threatening radionuclide in a sample volume to appropriate
personnel. The invention furthermore provides methods for
accomplishing the above-disclosed detection, identification,
communication and warning.
Inventors: |
Gentile; Charles A.;
(Plainsboro, NJ) ; Carpe; Andrew F.; (Hammonton,
NJ) ; Langish; Stephen W.; (Eastampton, NJ) |
Correspondence
Address: |
REED SMITH LLP
2500 ONE LIBERTY PLACE
1650 MARKET STREET
PHILADELPHIA
PA
19103
US
|
Family ID: |
38235572 |
Appl. No.: |
11/724052 |
Filed: |
March 14, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11344026 |
Jan 31, 2006 |
7244948 |
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11724052 |
Mar 14, 2007 |
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10384236 |
Mar 6, 2003 |
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11344026 |
Jan 31, 2006 |
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60375137 |
Apr 24, 2002 |
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Current U.S.
Class: |
250/393 ;
702/27 |
Current CPC
Class: |
G01T 1/167 20130101;
G01V 5/0075 20130101; G01V 5/0091 20130101 |
Class at
Publication: |
250/393 ;
702/027 |
International
Class: |
G01T 1/167 20060101
G01T001/167; G06F 19/00 20060101 G06F019/00 |
Goverment Interests
GOVERNMENT RIGHTS
[0002] The present invention was made with Government support and
the Government has certain rights in the invention.
Claims
1. A digital computational apparatus comprising a) a device
programmed to perform steps comprising i) comparing characteristics
of a sample signal with corresponding characteristics of a
plurality of reference signals; and ii) determining whether
characteristics of the sample signal are similar to or identical to
characteristics of at least one reference signal; and b) a memory
device in which is stored data providing characteristics of a
plurality of reference signals; wherein each reference signal
characterizes a signal waveform of a target radionuclide or a
threatening radionuclide.
2. The digital computational apparatus described in claim 1 wherein
a target radionuclide or a threatening radionuclide is chosen from
a set comprising cesium-137, cobalt-60, strontium-90, iridium-192,
americium-241, manganese-54, iron-55, iodine-125, iodine-130,
iodine-131, molybdenum-99, technetium-99m, uranium-235,
uranium-238, a transuranium radionuclide, a plutonium-beryllium
source, a californium source, and a radioactive decay product of
uranium.
3. A high throughput apparatus for detection of a target
radionuclide in a sample volume, or for identifying a target
radionuclide present in a sample volume, or both, comprising a)
detecting means for detecting radiation emanating from a
radionuclide in a sample volume, wherein the detecting means
produces a sample signal characteristic of the radionuclide; b)
analyzing means for analyzing the sample signal to identify its
characteristics, wherein the analyzing means interacts with the
detecting means; c) identifying means for determining whether
characteristics of the sample signal are similar or identical to a
signal characteristic of a target radionuclide, and wherein the
identifying means interacts with the analyzing means, whereby if
the sample signal is determined to be so similar or identical the
apparatus has detected the target radionuclide, and whereby the
apparatus, by identifying the sample signal as being so similar or
identical, identifies a target radionuclide in the sample
volume.
4. The apparatus described in claim 3 wherein the radiation
detected is a neutron, a gamma ray or an x-ray, an alpha particle,
a beta particle or any combination thereof, or all of them.
5. The apparatus described in claim 3 wherein the radiation
detected is a neutron, a gamma ray or an x-ray, or any combination
thereof, or all of them.
6. The apparatus described in claim 3 wherein the detecting means
comprises a scintillation detector, a solid state gamma ray
detector, a solid state x-ray detector, or a neutron detector, or
any combination thereof, or all of them.
7. The apparatus described in claim 3 wherein a target radionuclide
is chosen from a set comprising cesium-137, cobalt-60,
strontium-90, iridium-192, americium-241, manganese-54, iron-55,
iodinei25, iodine-130, iodine-131, molybdenum-99, technetium-99m,
uranium-235, uranium-238, a transuranium radionuclide, a
plutonium-beryllium source, a californium source, and a radioactive
decay product of uranium.
8. The apparatus described in claim 3 wherein the apparatus detects
and identifies a plurality of target radionuclides chosen from
among cesium-137, cobalt-60, strontium-90, iridium-192,
americium-241, manganese-54, iron-55, iodine-125, iodine-130,
iodine-131, molybdenum-99, technetium 99m, uranium-235,
uranium-238, a transuranium radionuclide, a plutonium-beryllium
source, a californium source, and a radioactive decay product of
uranium.
9. The apparatus described in claim 3 that detects or identifies or
both in an elapsed time from about 0.1 second to about 10
seconds.
10. The apparatus described in claim 9 wherein the elapsed time is
about 0.1 second to about 4 seconds.
11. The apparatus described in claims 9 wherein the elapsed time is
about 0.1 second to about 0.5 second.
12. A high throughput apparatus for communicating the presence of a
target radionuclide in a sample volume, the identity of a target
radionuclide in a sample volume, or both, comprising a) detecting
means for detecting radiation emanating from a radionuclide in a
sample volume, wherein the detecting means produces a sample signal
characteristic of the radionuclide; b) analyzing means for
analyzing the sample signal to identify its characteristics,
wherein the analyzing means interacts with the detecting means; c)
identifying means for determining whether characteristics of the
sample signal are similar or identical to a signal characteristic
of a target radionuclide, and wherein the identifying means
interacts with the analyzing means; and d) communicating means that
communicates a determination that the sample signal is so similar
or identical; whereby the apparatus communicates the presence of
the target radionuclide in the sample volume, and whereby the
apparatus communicates the identity of the target radionuclide in
the sample volume.
13. The apparatus described in claim 12 wherein the radiation
detected is a neutron, a gamma ray or an x-ray, an alpha particle,
a beta particle or any combination thereof, or all of them.
14. The apparatus described in claim 12 wherein the radiation
detected is a neutron, a gamma ray or an x-ray, or any combination
thereof, or all of them.
15. The apparatus described in claim 12 wherein the detecting means
comprises a scintillation detector, a solid state gamma ray
detector, a solid state x-ray detector, a neutron detector, or any
combination thereof, or all of them.
16. The apparatus described in claim 12 wherein a target
radionuclide is chosen from a set comprising cesium-137, cobalt-60,
strontium-90, iridium-192, americium-241, manganese-54, iron-55,
iodinei25, iodine-130, iodine-131, molybdenum-99, technetium-99m,
uranium-235, uranium-238, a transuranium radionuclide, a
plutonium-beryllium source, a californium source, and a radioactive
decay product of uranium.
17. The apparatus described in claim 12 wherein the apparatus
communicates the presence and identity of a plurality of target
radionuclides chosen from among cesium-137, cobalt-60,
strontium-90, iridium-192, americium-241, manganese-54, iron-55,
iodine-125, iodine-130, iodine-131, molybdenum-99, technetium-99m,
uranium-235, uranium-238, a transuranium radionuclide, a
plutonium-beryllium source, a californium source, and a radioactive
decay product of uranium.
18. The apparatus described in claim 12 that detects or identifies
or both in an elapsed time from about 0.1 second to about 10
seconds.
19. The apparatus described in claim 18 wherein the elapsed time is
about 0.1 second to about 4 seconds.
20. The apparatus described in claims 18 wherein the elapsed time
is about 0.1 second to about 0.5 second.
21. A high throughput apparatus for warning of the presence and/or
the identity of a threatening radionuclide in a sample volume,
comprising a) detecting means for detecting radiation emanating
from a radionuclide in a sample volume, wherein the detecting means
produces a sample signal characteristic of the radionuclide; b)
analyzing means for analyzing the sample signal to identify its
characteristics, wherein the analyzing means interacts with the
detecting means; c) comparing means for comparing characteristics
of the sample signal to a set of signals, wherein each member of
the set is a signal that is characteristic of a threatening
radionuclide, wherein the comparing means interacts with the
analyzing means; d) identifying means for determining whether
characteristics of the sample signal are similar or identical to a
signal characteristic of a threatening radionuclide, and wherein
the identifying means interacts with the comparing means; and e)
warning means that warns that the sample signal is determined to be
so similar or identical; whereby the apparatus warns of the
presence of the threatening radionuclide in the sample volume, and
whereby the apparatus warns of the identity of the threatening
radionuclide in the sample volume.
22. The apparatus described in claim 21 wherein the radiation
detected is a neutron, a gamma ray or an x-ray, an alpha particle,
a beta particle or any combination thereof, or all of them.
23. The apparatus described in claim 21 wherein the radiation
detected is a neutron, a gamma ray or an x-ray, or any combination
thereof, or all of them.
24. The apparatus described in claim 21 wherein the detecting means
comprises a scintillation detector, a solid state gamma ray
detector, a solid state x-ray detector, a neutron detector, or any
combination thereof, or all of them.
25. The apparatus described in claim 21 wherein a target
radionuclide is chosen from a set comprising cesium-137, cobalt-60,
strontium-90, iridium-192, americium-241, manganese-54, iron-55,
iodine-125, iodine-130, iodine-131, molybdenum-99, technetium-99m,
uranium-235, uranium-238, a transuranium radionuclide, a
plutonium-beryllium source, a californium source, and a radioactive
decay product of uranium.
26. The apparatus described in claim 21 wherein the apparatus
provides a warning of the presence and identity of a plurality of
target radionuclides chosen from among cesium-137, cobalt-60,
strontium-90, iridium-192, americium-241, manganese-54, iron-55,
iodine-125, iodine-130, iodine-131, molybdenum-99, technetium-99m,
uranium-235, uranium-238, a transuranium radionuclide, a
plutonium-beryllium source, a californium source, and a radioactive
decay product of uranium.
27. The apparatus described in claim 21 that detects or identifies
or both in an elapsed time from about 0.1 second to about 10
seconds.
28. The apparatus described in claim 27 wherein the elapsed time is
about 0.1 second to about 4 seconds.
29. The apparatus described in claims 27 wherein the elapsed time
is about 0.1 second to about 0.5 second.
30. A method for detecting a target radionuclide in a sample
volume, or for identifying a target radionuclide present in a
sample volume, or both, comprising the steps of a) juxtaposing the
sample volume and a detecting means that detects radiation
emanating from a radionuclide such that the detecting means detects
radiation emanating from the sample volume; b) detecting radiation
emanating from a radionuclide in the sample volume, wherein the
detecting means produces a sample signal characteristic of the
radionuclide; c) analyzing the sample signal produced in step b) to
identify its characteristics; d) determining whether identified
characteristics of the sample signal are similar or identical to a
signal characteristic of the target radionuclide; whereby if the
sample signal is determined to be so similar or identical the
target radionuclide is detected, and whereby identifying the sample
signal as being so similar or identical identifies a target
radionuclide in the sample volume.
31. The method described in claim 30 wherein the radiation detected
is a neutron, a gamma ray or an x-ray, an alpha particle, a beta
particle or any combination thereof, or all of them.
32. The method described in claim 30 wherein the radiation detected
is a neutron, a gamma ray or an x-ray, or any combination thereof,
or all of them.
33. The method described in claim 30 wherein the detecting means
comprises a scintillation detector, a solid state gamma ray
detector, a solid state x-ray detector, a neutron detector, or any
combination thereof, or all of them.
34. The method described in claim 30 wherein a target radionuclide
is chosen from a set comprising cesium-137, cobalt-60,
strontium-90, iridium-192, americium-241, manganese-54, iron-55,
iodine-125, iodine-130, iodine-131, molybdenum-99, technetium-99m,
uranium-235, uranium-238, a transuranium radionuclide, a
plutonium-beryllium source, a californium source, and a radioactive
decay product of uranium.
35. The method described in claim 30 wherein the method detects and
identifies a plurality of target radionuclides chosen from among
cesium-137, cobalt-60, strontium-90, iridium-192, americium-241,
manganese-54, iron-55, iodine-125, iodine-130, iodine-131,
molybdenum-99, technetium 99m, uranium-235, uranium-238, a
transuranium radionuclide, a plutonium-beryllium source, a
californium source, and a radioactive decay product of uranium.
36. The method described in claim 30 that detects or identifies or
both in an elapsed time from about 0.1 second to about 10
seconds.
37. The method described in claim 36 wherein the elapsed time is
about 0.1 second to about 4 seconds.
38. The method described in claims 36 wherein the elapsed time is
about 0.1 second to about 0.5 second.
39. A method for communicating the presence of a target
radionuclide in a sample volume, the identity of a target
radionuclide in a sample volume, or both, comprising the steps of
a) juxtaposing the sample volume and a detecting means that detects
radiation emanating from a radionuclide such that the detecting
means detects radiation emanating from the sample volume; and b)
detecting radiation emanating from a radionuclide in a sample
volume, wherein the detecting means produces a sample signal
characteristic of the radionuclide; c) analyzing the sample signal
to identify its characteristics; d) determining whether
characteristics of the analyzed sample signal are similar or
identical to a signal characteristic of a target radionuclide; and
e) communicating a determination that the characteristics of the
sample signal are so similar or identical; thereby communicating
the presence of the target radionuclide in the sample volume, or
the identity of the target radionuclide in the sample volume as
having signal characteristics similar or identical to the sample
signal.
40. The method described in claim 39 wherein the radiation detected
is a neutron, a gamma ray or an x-ray, an alpha particle, a beta
particle or any combination thereof, or all of them.
41. The method described in claim 39 wherein the radiation detected
is a neutron, a gamma ray or an x-ray, or any combination thereof,
or all of them.
42. The method described in claim 39 wherein the detecting means
comprises a scintillation detector, a solid state gamma ray
detector, a solid state x-ray detector, a neutron detector, or any
combination thereof, or all of them.
43. The method described in claim 39 wherein a target radionuclide
is chosen from a set comprising cesium-137, cobalt-60,
strontium-90, iridium-192, americium-241, manganese-54, iron-55,
iodine-125, iodine-130, iodine-131, molybdenum-99, technetium-99m,
uranium-235, uranium-238, a transuranium radionuclide, a
plutonium-beryllium source, a californium source, and a radioactive
decay product of uranium.
44. The method described in claim 39 wherein the method
communicates the presence and identity of a plurality of target
radionuclides chosen from among cesium-137, cobalt-60,
strontium-90, iridium-192, americium-241, manganese-54, iron-55,
iodine-125, iodine-130, iodine-131, molybdenum-99, technetium-99m,
uranium-235, uranium-238, a transuranium radionuclide, a
plutonium-beryllium source, a californium source, and a radioactive
decay product of uranium.
45. The method described in claim 39 that detects or identifies or
both in an elapsed time from about 0.1 second to about 10
seconds.
46. The method described in claim 45 wherein the elapsed time is
about 0.1 second to about 4 seconds.
47. The method described in claims 45 wherein the elapsed time is
about 0.1 second to about 0.5 second.
48. A method for warning of the presence and/or the identity of a
threatening radionuclide in a sample volume, comprising the steps
of a) juxtaposing the sample volume and a detecting means for
detecting radiation emanating from a radionuclide such that the
detecting means detects radiation emanating from the sample volume,
wherein the detecting means produces a sample signal characteristic
of the radionuclide; b) analyzing the sample signal to identify its
characteristics; c) comparing characteristics of the analyzed
sample signal to a set of signals, wherein each member of the set
is a signal that is characteristic of a threatening radionuclide;
d) determining that the characteristics of the analyzed sample
signal are similar or identical to a signal characteristic of a
threatening radionuclide; and e) warning that the sample signal is
determined to be so similar or identical; thereby warning of the
presence of the threatening radionuclide in the sample volume,
and/or warning of the identity of a threatening radionuclide
present in the sample volume.
49. The method described in claim 48 wherein the radiation detected
is a neutron, a gamma ray or an x-ray, an alpha particle, a beta
particle or any combination thereof, or all of them.
50. The method described in claim 48 wherein the radiation detected
is a neutron, a gamma ray or an x-ray, or any combination thereof,
or all of them.
51. The method described in claim 48 wherein the detecting means
comprises a scintillation detector, a solid state gamma ray
detector, a solid state x-ray detector, a neutron detector, or any
combination thereof, or all of them.
52. The method described in claim 48 wherein a target radionuclide
is chosen from a set comprising cesium-137, cobalt-60,
strontium-90, iridium-192, americium-241, manganese-54, iron-55,
iodine-125, iodine-130, iodine-131, molybdenum-99, technetium-99m,
uranium-235, uranium-238, a transuranium radionuclide, a
plutonium-beryllium source, a californium source, and a radioactive
decay product of uranium.
53. The method described in claim 48 wherein the method provides a
warning of the presence and identity of a plurality of target
radionuclides chosen from among cesium-137, cobalt-60,
strontium-90, iridium-192, americium-241, manganese-54, iron-55,
iodine-125, iodine-130, iodine-131, molybdenum-99, technetium-99m,
uranium-235, uranium-238, a transuranium radionuclide, a
plutonium-beryllium source, a californium source, and a radioactive
decay product of uranium.
54. The method described in claim 48 that detects or identifies or
both in an elapsed time from about 0.1 second to about 10
seconds.
55. The method described in claim 54 wherein the elapsed time is
about 0.1 second to about 4 seconds.
56. The method described in claims 54 wherein the elapsed time is
about 0.1 second to about 0.5 second.
Description
RELATED APPLICATION
[0001] This application claims the benefit of priority of Utility
application Ser. No. 11/344,026, filed Jan. 31, 2006.
FIELD OF THE INVENTION
[0003] This invention relates to rapidly detecting and identifying
certain nuclear isotopes. More particularly, the invention relates
to an apparatus and methods for detecting radionuclides in a sample
that are potentially dangerous in uses, such as antisocietal or
terrorist activities, that threaten cultural, political or economic
structures of civilized society.
BACKGROUND OF THE INVENTION
[0004] Modern society, in the past one to two decades, has become
subject to antisocietal activities of groups such as terrorist
organizations, freedom fighters, individuals of radical persuasion,
and individuals holding to anarchist or nihilistic philosophies.
Such groups and individuals consider several potential means for
physically attacking the fundamental structures of civilized
societies. These include deployment and use of weapons of mass
destruction, among which are nuclear devices.
[0005] Nuclear devices include those which upon triggering produce
a fissioning nuclear explosion or a fusion thermonuclear explosion,
and a so-called "dirty bomb". In a dirty bomb, an explosion is
triggered with the objective of dispersing various toxic or
radiologically hazardous radionuclides into an environment with the
intent of causing radioactive contamination in a wide physical
area. Although only a few selected radionuclides are of use in
preparing a fission bomb and in providing the trigger for a fusion
bomb, a wide range of radionuclides may potentially be included in
a dirty bomb. Radionuclides that are candidates for use in
antisocietal devices such as fission bombs, thermonuclear bombs and
dirty bombs are termed "threatening" herein. It is believed that
the choice of threatening components includes radionuclides with
long half-lives for radioactive decay, as well as radionuclides
such as those used in medical diagnostics and various research
endeavors, which generally have short half-lives. It is important
in screening operations to have the capability of detecting and
identifying any of the radionuclides potentially usable in a
nuclear device.
[0006] Since nuclear devices such as those described above may be
assembled or deployed at any location within the geographical
boundaries of a nation, it would be advantageous for governmental
authorities to have the capability of screening for component
radionuclides at widely dispersed locations. Common nonlimiting
examples of such locations include automotive highways, airports,
train stations, municipal mass transit systems, governmental
buildings and freight handling facilities. Beneficially the
screening installations would be automated and able to operate free
of human intervention as long as no radionuclides are detected, but
to alert appropriate authorities when a positive detection and/or
identification of a specific radionuclide deemed to be a threat is
made.
[0007] In summary there remains a need for a system and methods to
detect and/or identify any of a wide range of radionuclides. There
is further a need for such systems and methods to operate rapidly,
automatically and independently of human intervention. There
remains a need for detection and/or identification systems and
methods capable of operating at high volume, and with high
throughput. There furthermore remains a need for a system and
methods to detect and identify a particular radionuclide from among
a set of candidate radionuclides that an antisocietal group or
individual might deploy. The present invention addresses these
outstanding needs.
SUMMARY OF THE INVENTION
[0008] In one aspect of the invention, a digital computational
apparatus is disclosed that includes [0009] a) a device programmed
to perform steps that include [0010] i) comparing characteristics
of a sample signal with corresponding characteristics of a
plurality of reference signals; and [0011] ii) determining whether
characteristics of the sample signal are similar to or identical to
characteristics of at least one reference signal; and [0012] b) a
memory device in which is stored data providing characteristics of
two or more reference signals; wherein each reference signal
characterizes a signal waveform of a target radionuclide or a
threatening radionuclide. In an important embodiment of the digital
computational apparatus, a target radionuclide or a threatening
radionuclide is chosen from a set that includes cesium-137,
cobalt-60, strontium-90, iridium-192, americium-241, manganese-54,
iron-55, iodine-125, iodine-130, iodine-131, molybdenum-99,
technetium-99m, uranium-235, uranium-238, a transuranium
radionuclide, a plutonium-beryllium source, a californium source,
or a radioactive decay product of uranium.
[0013] In another aspect, the invention discloses a high throughput
apparatus for detection of a target radionuclide in a sample
volume, or for identifying a target radionuclide present in a
sample volume, or both, that includes [0014] a) detecting means for
detecting radiation emanating from a radionuclide in a sample
volume, wherein the detecting means produces a sample signal
characteristic of the radionuclide; [0015] b) analyzing means for
analyzing the sample signal to identify its characteristics,
wherein the analyzing means interacts with the detecting means;
[0016] c) identifying means for determining whether characteristics
of the sample signal are similar or identical to a signal
characteristic of a target radionuclide, and wherein the
identifying means interacts with the analyzing means; whereby if
the sample signal is determined to be so similar or identical the
apparatus has detected the target radionuclide, and whereby the
apparatus, by identifying the sample signal as being so similar or
identical, identifies a target radionuclide in the sample
volume.
[0017] In a further aspect the invention discloses a high
throughput apparatus for communicating the presence of a target
radionuclide in a sample volume, the identity of a target
radionuclide in a sample volume, or both, that includes [0018] a)
detecting means for detecting radiation emanating from a
radionuclide in a sample volume, wherein the detecting means
produces a sample signal characteristic of the radionuclide; [0019]
b) analyzing means for analyzing the sample signal to identify its
characteristics, wherein the analyzing means interacts with the
detecting means; [0020] c) identifying means for determining
whether characteristics of the sample signal are similar or
identical to a signal characteristic of a target radionuclide, and
wherein the identifying means interacts with the analyzing means;
and [0021] d) communicating means that communicates a determination
that the sample signal is so similar or identical; whereby the
apparatus communicates the presence of the target radionuclide in
the sample volume, and whereby the apparatus communicates the
identity of the target radionuclide in the sample volume.
[0022] In yet another aspect, the invention provides a high
throughput apparatus for warning of the presence and/or the
identity of a threatening radionuclide in a sample volume, that
includes [0023] a) detecting means for detecting radiation
emanating from a radionuclide in a sample volume, wherein the
detecting means produces a sample signal characteristic of the
radionuclide; [0024] b) analyzing means for analyzing the sample
signal to identify its characteristics, wherein the analyzing means
interacts with the detecting means; [0025] c) comparing means for
comparing characteristics of the sample signal to a set of signals,
wherein each member of the set is a signal that is characteristic
of a threatening radionuclide, wherein the comparing means
interacts with the analyzing means; [0026] d) identifying means for
determining whether characteristics of the sample signal are
similar or identical to a signal characteristic, of a threatening
radionuclide, and wherein the identifying means interacts with the
comparing means; and [0027] e) warning means that warns that the
sample signal is determined to be so similar or identical; whereby
the apparatus warns of the presence of the threatening radionuclide
in the sample volume, and whereby the apparatus warns of the
identity of the threatening radionuclide in the sample volume.
[0028] In a further aspect, a method is disclosed for detecting a
target radionuclide in a sample volume, or for identifying a target
radionuclide present in a sample volume, or both, that includes the
steps of [0029] a) juxtaposing the sample volume and a detecting
means that detects radiation emanating from a radionuclide such
that the detecting means detects radiation emanating from the
sample volume; [0030] b) detecting radiation emanating from a
radionuclide in the sample volume, wherein the detecting means
produces a sample signal characteristic of the radionuclide; [0031]
c) analyzing the sample signal produced in step b) to identify its
characteristics; [0032] d) determining whether identified
characteristics of the sample signal are similar or identical to a
signal characteristic of the target radionuclide; whereby if the
sample signal is determined to be so similar or identical the
target radionuclide is detected, and whereby identifying the sample
signal as being so similar or identical identifies a target
radionuclide in the sample volume.
[0033] In still another aspect, the invention discloses a method
for communicating the presence of a target radionuclide in a sample
volume, the identity of a target radionuclide in a sample volume,
or both, that includes the steps of [0034] a) juxtaposing the
sample volume and a detecting means that detects radiation
emanating from a radionuclide such that the detecting means detects
radiation emanating from the sample volume; and [0035] b) detecting
radiation emanating from a radionuclide in a sample volume, wherein
the detecting means produces a sample signal characteristic of the
radionuclide; [0036] c) analyzing the sample signal to identify its
characteristics; [0037] d) determining whether characteristics of
the analyzed sample signal are similar or identical to a signal
characteristic of a target radionuclide; and [0038] e)
communicating a determination that the characteristics of the
sample signal are so similar or identical; thereby communicating
the presence of the target radionuclide in the sample volume, or
the identity of the target radionuclide in the sample volume as
having signal characteristics similar or identical to the sample
signal.
[0039] In yet a further aspect, the invention discloses a method
for warning of the presence and/or the identity of a threatening
radionuclide in a sample volume, that includes the steps of [0040]
a) juxtaposing the sample volume and a detecting means for
detecting radiation emanating from a radionuclide such that the
detecting means detects radiation emanating from the sample volume,
wherein the detecting means produces a sample signal characteristic
of the radionuclide; [0041] b) analyzing the sample signal to
identify its characteristics; [0042] c) comparing characteristics
of the analyzed sample signal to a set of signals, wherein each
member of the set is a signal that is characteristic of a
threatening radionuclide; [0043] d) determining that the
characteristics of the analyzed sample signal are similar or
identical to a signal characteristic of a threatening radionuclide;
and [0044] e) warning that the sample signal is determined to be so
similar or identical; [0045] thereby warning of the presence of the
threatening radionuclide in the sample volume, and/or warning of
the identity of a threatening radionuclide present in the sample
volume.
[0046] In the various aspects of the apparatus and methods
disclosed in this invention, significant embodiments include those
wherein the radiation detected is a neutron, a gamma ray or an
x-ray, an alpha particle, a beta particle or any combination
thereof, or all of them. In a further significant embodiment the
radiation detected is a neutron, a gamma ray or an x-ray, or any
combination thereof, or all of them. In yet another important
embodiment, the detecting means includes a scintillation detector,
a solid-state gamma ray detector, a solid-state x-ray detector, a
neutron detector, or any combination thereof, or all of them.
[0047] In additional advantageous embodiments, a target
radionuclide or the threatening radionuclide is chosen from a set
that includes cesium-137, cobalt-60, strontium-90, iridium-192,
americium-241, manganese-54, iron-55, iodine-125, iodine-130,
iodine-131, molybdenum-99, technetium-99m, uranium-235,
uranium-238, a transuranium radionuclide, a plutonium-beryllium
source, a californium source. or a radioactive decay product of
uranium; or two or more target radionuclides or threatening
radionuclides are chosen from among cesium-137, cobalt-60,
strontium-90, iridium-192, americium-241, manganese-54, iron-55,
iodine-125, iodine-130, iodine-131, molybdenum-99, technetium-99m,
uranium-235, uranium-238, a transuranium radionuclide, a
plutonium-beryllium source, a californium source, and radioactive
decay products of uranium.
[0048] In another significant embodiment, the apparatuses and
methods can detect and/or identify, or communicate, or warn of, a
target radionuclide or a threatening radionuclide in an elapsed
time from about 0.1 second to about 10 seconds. More significantly,
the elapsed time is about 0.1 second to about 4 seconds, and still
more significantly, the elapsed time is about 0.1 second to about
0.5 second.
BRIEF DESCRIPTION OF THE DRAWINGS
[0049] FIG. 1. Block diagram representation of an embodiment of the
invention.
[0050] FIG. 2. Photographic image of a housing containing a
detector employed in the apparatus of the invention installed
adjacent to a motor vehicle lane.
[0051] FIG. 3. Graphical representations of digital data provided
by a multichannel analyzer for various samples placed in a sample
volume in front of a detector. Elapsed analysis time is 4 sec.
Panel A, Background; Panel B, Am-241, unshielded, detected at a
distance of 10 feet; Panel C, Co-60 shielded by 1 inch of lead,
detected at a distance of 6 feet; Panel D, Co-60 shielded by 1 inch
of lead and Am-241 unshielded, detected at a distance of 6
feet.
[0052] FIG. 4. Graphical representations of digital data provided
by a multichannel analyzer for various samples placed in a sample
volume in front of a detector. Elapsed analysis time is 0.5 sec.
Panel A, Background; Panel B, Cs-137 shielded with 1 inch of lead,
detected at a distance of 6 feet; Panel C, Cs137, unshielded,
detected at a distance of 6 feet; Panel D, Co-60, Cs-137 and
Am-241, unshielded, detected at a distance of 6 feet.
DETAILED DESCRIPTION OF THE INVENTION
[0053] The present invention provides systems and methods to detect
and/or identify any of a wide range of radionuclides. The systems
and methods of the invention carry out the detection and/or
identification rapidly, automatically and independently of human
intervention. The present system and methods for detection and/or
identification are capable of operating at high sampling rates, and
with high throughput. As a result they may be installed in
locations throughout the social, economic and infrastructure
facilities of a nation, especially those facilities through which
there is a high volume of public traffic. These include highways,
where the systems may be installed at tollbooths or comparable lane
facilities, train stations, airports, metropolitan mass transit
systems, and in governmental and commercial buildings. In addition
the systems of the invention may be installed in facilities used
for transfer and transport of commercial goods. Nonlimiting
examples of such facilities include truck terminals, railroad
freight handling facilities, air transport facilities, and shipping
ports receiving goods offloaded from ships. The invention still
further provides a system and methods that detect and identify a
particular radionuclide from among a set of candidate radionuclides
that an antisocietal group or individual might deploy. The system
and methods include the capability of providing an alarm or similar
notification of a positive detection and/or identification of a
suspect radionuclide in a sample. These capabilities permit
assessing the nature of a threat as soon as it is detected.
[0054] As used herein, the phrase "digital computational apparatus"
and similar related phrases are directed in general to a system
that includes, but is not limited to, a processing unit, a unit
with a subject program resident in a component such that the
program is executable when needed to carry out the purposes of the
present invention, and a memory storage component. In addition a
digital computational apparatus commonly has one or more input
modules to accept signals from a source, and one or more output
modules transmitting a computational result. Any apparatus
constituted to carry out the computational functions required to
implement or employed in implementing the present invention are
included within the scope of a "digital computational
apparatus".
[0055] As used herein, the term "self-contained" and similar
related terms are directed to the property of an apparatus or a
module of an apparatus that all components of the apparatus, or of
the module, are contained within a housing. The components are
small enough that the overall dimensions of a housing containing
the apparatus of the invention are relatively small. The advantage
of the self-contained attribute of an apparatus or module of the
invention is that it thereby may be installed with ease in any
location where its use is desired or recommended.
[0056] As used herein, the term "high throughput" and related
similar terms are directed to the property that an apparatus of the
present invention has high sensitivity and short analysis time such
that it may usefully be deployed in facilities in which each
analysis must be carried out rapidly and relatively innocuously.
Thus terms such as "high sensitivity", "rapid analysis", "short
analysis time", use in "high traffic areas", and the like, are all
comprehended within the meaning of the term "high throughput".
[0057] As used herein, the terms "characteristic",
"characteristics", and similar related terms, are directed to a
group of properties or elements of information that a signal may
have that are typical for a particular signal, originating from a
particular radionuclide, and that distinguish the signal from other
signals originating from different radionuclides. Nonlimiting
examples of properties that may be included when using the terms
"characteristic", "characteristics" or related terms, are the
energy or energies of photons or the type of a particle that
constitutes the radiation emanating from a radionuclide, a
particular peak of the radiation in a waveform, and the bandwidth
of a particular peak in a signal. An example of a measure of
bandwidth is the width of a peak at half-maximal peak height. A
radionuclide may be associated with one or more particular peaks in
a spectrum; the overall set of characteristics for a radionuclide
may be termed a "signature", a "signature pattern" a "waveform",
"spectrum", and the like. As used herein, the phrase "sample
volume" and related phrases are directed to volumes of space which
are subject to screening or sampling by the system and methods of
the present invention.
[0058] Nonlimiting examples of such sample volumes include the
volume of space occupied by an automobile, van, truck, tractor
trailer, or similar road vehicles, or any portion thereof, a
railroad car, wagon, or container placed on or in a railroad car or
wagon, or any portion thereof, a boat, ship or similar naval
vessel, or any container placed on or in such a naval vessel, or
any portion thereof, personal luggage, baggage and goods carried by
individuals, and so forth. Any equivalent sample volume subject to
screening or sampling by the systems and methods of the invention
are contemplated to fall within the scope of the invention.
[0059] As used herein, the terms "sample" or "sample signal" and
similar related terms are directed to a signal, or a set of
characteristics, that result from interrogating a sample volume
during the operation of an apparatus or method of the present
invention. The characteristics of the signal include the elements
of information set forth above in the definition of
"characteristics". Thus a sample or sample signal originates in
real time as each subject that includes a sample volume comes under
the scrutiny of the system and methods of the instant invention.
The sample or sample signal includes the characteristics of any
radionuclide present in the sample volume.
[0060] As used herein, the terms "reference" and "reference
signal", and similar related terms, are directed to a group of
properties or elements of information characteristic of a reference
radionuclide or a standard radionuclide. The reference or standard
radionuclide is any one of a set of candidate radionuclides or
threatening radionuclides against which a sample is being screened.
In important applications of the present invention, a candidate
radionuclide or threatening radionuclide is deemed dangerous or
threatening to society were it to be present in a nuclear device.
Examples of reference radionuclides, together with representative
characteristics thereof, are provided below in the present
disclosure. As used herein, the terms "reference" or "reference
signal" also relate to equivalent or analogous radionuclides not
specifically identified herein but that nevertheless are or become
deemed to be dangerous or threatening to society. In advantageous
embodiments of the present invention a set of reference signals is
made available to the system and methods of the invention in a
storage device, memory device or storage medium.
[0061] As used herein the term "interact" and similar related terms
are directed to indicating that two components or modules in an
apparatus interact with each other in a way that permits the
transfer or exchange of information between the two components or
modules. The information commonly is an electronic signal in analog
or digital form. In one embodiment the interaction can be means of
solid electrical conductors such as wires, cables, waveguides, or
fiber optical connectors, and the like; in an alternative form the
interaction can be by means of electromagnetic radiation generated
by one of the components and received by the second. In general any
equivalent means of permitting communication between the components
of a system are contemplated as being encompassed by
"interacting".
[0062] As used herein the term "identical" and similar related
terms, when used to describe a sample signal or sample generally,
is intended to indicate that the signal from the sample has
characteristics that are identifiable as being those of a reference
or standard. For example, if a set of characteristics include
properties such as a particle of radiation, or a photon of
radiation, and a bandwidth of a peak in a spectrum, an identical
sample would have values for a characteristic attribute that are
less than 1.0 standard deviation, preferably less than 0.75
standard deviation, preferably less than 0.5 standard deviation,
more preferably less than 0.3 standard deviation, more preferably
less than 0.25 standard deviation, more preferably still less than
0.2 standard deviation, more preferably less than 0.15 standard
deviation, more preferably less than 0.1 standard deviation, or
more preferably still less than 0.05 standard deviation different
from the value of a reference signal for the same characteristic.
Other measures to establish similarity and identity may also be
used. Depending on computational methods used to identify
components in a sample waveform (see below), any statistical
measure that establishes similarity or identity within a given
limit of certainty or with a given probability may be used. For
example, identity may be established with a p-value of p<0.01,
or p<.sub.--0.005, or p<0.001.
[0063] As used herein the term "similar" and related terms, when
used to describe a sample signal or sample generally, is intended
to indicate that the signal from the sample has characteristics
that are identifiable as resembling those of a reference or
standard sufficiently closely to be identifiable as being the
characteristic of the particular reference or standard. For
example, if a set of characteristics include properties such as a
particle of radiation, or a photon of radiation, and a bandwidth of
a peak in a spectrum, an identical sample would have values for a
characteristic attribute that are less than 3.0 standard
deviations, preferably less than 2.5 standard deviations,
preferably less than 2.0 standard deviation, more preferably less
than 1.5 standard deviation, more preferably between 1.5 standard
deviations and 1.0 standard deviation different from the value of a
reference signal for the same characteristic. Similarity may be
likewise be established with a p-value of p <0.1, or p<0.05,
or p<0.02. As used herein, the term "target", and similar
related terms, when used to describe a radionuclide, are directed
to any one of a set of radionuclides identified as being one whose
presence in a sample volume is to be assayed. The identities of
target radionuclides are established at any time by appropriate
authorities. It is contemplated to be within the scope of the
invention that the set of target radionuclides may change over
time. In particular, it is possible that new target radionuclides
may be added to a set over the course of time, or that certain
radionuclides may be substituted for others. Any radionuclide
identified by appropriate authorities at any time as being of
interest to be detected in a sample volume is contemplated to be a
target as used herein.
[0064] As used herein, the terms "analysis", "analyzing" and
related similar terms are directed to processes such as generating
a radiation spectrum, or a waveform, or a characteristic signature
pattern from a signal provided by a detecting means of the
invention. An aspect of analysis or analyzing may include
transformation of a signal from a detecting means, which is
commonly an analog signal, into a digital representation of the
spectrum, waveform, or characteristic signature pattern. The
digital representation may serve as input information for an
identifying means.
[0065] As used herein, the terms "identifying", "identification"
and similar related terms are directed to determining whether
characteristics of the sample signal are similar or identical to a
signal characteristic of a target radionuclide or a threatening
radionuclide. Entities that may be employed in identifying include,
by way of nonlimiting example, hardware and software components
programmed to establish the similarity, identity, or lack thereof,
of a waveform to one or more reference radiation spectra,
waveforms, or characteristic signature patterns.
[0066] As used herein, the terms "comparing", "comparison" and
similar related terms are directed to assessing whether a signal
includes or is comprised of contributions from one or more
reference spectra or reference waveforms. In certain embodiments, a
set of reference spectra is stored in a digital storage medium and
is available to hardware and software components programmed to
carry out a comparison.
[0067] As used herein, the term "communicating" and similar related
terms are directed to providing a cue or response to a person such
that the person will understand that an apparatus has detected that
a sample signal is similar or identical to a reference signal or a
signal characteristic of a target radionuclide. Any sensory cue or
response that informs the person of the detection event is
understood to be included when a result is communicated. By way of
nonlimiting example, detection can be communicated by a visual cue,
an auditory cue, a contact, vibration or electrical cue, a
printout, an electronic display, and so on. Any equivalent way of
providing a cue or response is envisioned to be within the scope of
the present invention.
[0068] As used herein, the term "threatening", and similar related
terms, when used to describe a radionuclide, are directed to any
one of a set of radionuclides identified as being one whose
presence in a sample volume to be assayed is considered to be a
threat to society. The identities of threatening radionuclides are
established at any time by appropriate authorities. It is
contemplated to be within the scope of the invention that the set
of threatening radionuclides may change over time. In particular,
it is possible that new threatening radionuclides may be added to a
set over the course of time, or that a radionuclide may be
substituted by another. Any radionuclide identified by appropriate
authorities at any time as being of interest to be detected in a
sample volume is contemplated to be "threatening" as used
herein.
[0069] As used herein, the term "warning" and similar related terms
are directed to alerting a person that a dangerous or threatening
radionuclide has been detected and that potentially additional
action is required to be taken essentially immediately. A warning
may be, by way of nonlimiting example, a sharp, strong or intense
sensory cue or response, such as a bright light, a flashing light,
an alarm sound or alarm horn, and so on. A warning may be
accompanied by a direct physical response automated to accompany
the warning. Such a physical response may include imposing a
physical barrier such that the person, vehicle or object that
comprises the sample volume, or that is in the vicinity of the
sample volume, is restrained from leaving the vicinity of the
sample volume. Any equivalent sensory cue or response, or physical
response, is contemplated to be within the scope of the present
invention.
[0070] An apparatus employed in the present invention is comprised
of at least three general modules, namely, a detector or a
plurality of detectors, an analog signal analysis module and a
digital signal recognition module. A generalized schematic diagram
of an embodiment of an apparatus of the invention is shown in FIG.
1. One or more detectors ("DETECTOR") provide a raw signal to an
analog signal analysis module ("ANALOG DOMAIN"), which directs the
signal to one among a plurality of alternative paths. The ANALOG
DOMAIN of FIG. 1 is a generalized example of an "analyzing means"
of the invention. In the representation shown in FIG. 1, two paths
are depicted. In the path on the left the designations have the
following meanings: "Pre-Amp", preamplifier; "Shaping Amp", shaping
amplifier; "MCA", multi-channel analyzer; in the alternative path
on the right the designation "ADC DSP" stands for analog-to-digital
converter digital signal processor. The output digital signal from
the ANALOG DOMAIN serves as the input for the DIGITAL DOMAIN shown
in FIG. 1. The DIGITAL DOMAIN generally includes hardware and
software modules that constitute or comprise a nonlimiting example
of an "identifying means" of the present invention. The DIGITAL
DOMAIN includes a set of reference spectral characteristics of all
or a representative selection of target radionuclides ("SPECTRA");
in exemplary embodiments the SPECTRA are recorded within a
permanent storage device. The digital domain also includes
computational modules programmed to process the digital input from
the analog domain into a form suitable for analysis ("SIGNAL
PROCESSING"), if needed, and for determining whether the input
signals include signal characteristics that are similar or
identical to at least one target radionuclide in the reference set
("SIMILAR? IDENTICAL?"). In the embodiment shown in FIG. 1, the
SIMILAR? IDENTICAL? decision module is an example of a "comparing
means" of the invention. The result of the determination is output
("RESULT"), and may be used to communicate information to an
operator, or to warn an operator of a threatening radionuclide.
[0071] The detectors contemplated for use in the present invention
include detectors that are sensitive to neutrons, gamma radiation,
x-ray radiation, alpha particle radiation, and beta particle
radiation. Alpha particles and beta particles may either be
detected directly, or as a result of bremsstrahlung radiation
(secondary radiation). In important embodiments of an apparatus of
the invention, detectors that are sensitive to neutrons, gamma
radiation and x-ray radiation are employed. Detectors are widely
available from commercial sources for the detection of these
various classes of radiation, and are readily known to workers of
skill in fields related to the present invention, including by way
of nonlimiting example, radiation physics, nuclear physics,
radiation chemistry, nuclear chemistry, environmental safety,
public health and safety, and the like. The radiation sensitive
component in various detectors include, by way of nonlimiting
example, BF.sub.3 (for neutrons), .sup.3He (He-3; for neutrons),
Nal (for gamma rays), Ge (for gamma rays), Cadmium Zinc Telluride
(for gamma rays (XRF Corp., Somerville, Mass.), solid state silicon
or silicon-positive-intrinsic-negative detectors (for gamma rays
and x-rays), Csl, cadmium telluride, mercuric iodide, and the
like.
[0072] One or more of these detectors may be deployed in an
apparatus of the invention. If more than one detector is present,
they interact with the analog signal analysis module in parallel
fashion such that information from each detector may be processed
as called for without the need for intervention by an operator.
Each detector is interfaced with a component in the analog signal
analysis module to provide a full breadth of radiation specificity
and sensitivity. One or more detectors are deployed in the
proximity of the sample volume to be interrogated; it is not
necessary that the analog signal analysis module or the digital
signal analysis module be physically deployed with the detector or
detectors. In one nonlimiting example of the present invention, a
set of detectors is incorporated into a physically protective
housing and placed in juxtaposition with an auto lane in order to
assay for signals emanating from a sample volume that would be
occupied by a passing motor vehicle. The housing shields against
physical damage and environmental corrosion. The detectors in the
housing are connected by cable to interact with the analog signal
analysis module, which, in this example, is at a remote location.
In general, the cable that effects the interaction between the set
of detectors and the analog signal analysis module may be comprised
of solid electrical conductors such as wires, or fiber optical
conductors, or waveguides, or the like. The detector or detectors
provide a raw signal response to the analog signal analysis module.
Detectors of radionuclear radiation are widely known among workers
of skill in fields related to the field of the invention. Such
fields include, by way of nonlimiting example, radiation physics,
nuclear physics, radiation chemistry, nuclear chemistry,
environmental safety, public health and safety, and the like. Any
equivalent detection module that captures the spectral dispersion
of radiation emanating from a sample volume is contemplated as
falling within the scope of the present invention.
[0073] The raw sample signal transmitted to the analog signal
analysis module may be processed in at least two alternative ways
(see FIG. 1). In one alternative, the sample signal is amplified
and refined, for example, by passing the signal in turn through a
preamplifier and a shaping amplifier. The amplified signal is
provided to a multichannel analyzer, which prepares a digital
representation of the waveform of the signal provided by the
detectors. In another alternative the sample signal from the
detector is provided directly to a module that serves as an
analog-to-digital converter and as a digital signal processor which
generates a digital representation of the waveform of the signal
generated by the detectors. The digital representation of the
sample waveform serves as the input for the digital domain (FIG.
1). Modules that capture waveforms provided by a detector module,
and provide digital representations thereof, are widely known among
workers of skill in fields related to the field of the invention.
Such fields include, by way of nonlimiting example, radiation
physics, nuclear physics, radiation chemistry, nuclear chemistry,
environmental safety, public health and safety, and the like. Any
equivalent module that serves to provide a digital representation
of the spectral dispersion of a signal is understood to be within
the scope of the present invention.
[0074] The digital domain includes several virtual modules that are
computational procedures that take place within a computational
device. Any of a wide range of computational devices is envisioned
within the scope of the invention. In one example, the
computational flow may be permanently incorporated into a hardware
based device, such as a digital chip or microchip. In a second
example, the computational flow may take place in a programmable
computer, wherein the computations are incorporated into software
stored in a memory device, and when implemented the memory device
controls and operates the computational flow. Other physical
embodiments of the computational flow occurring within the digital
domain represented in FIG. 1 are envisioned to be within the scope
of the present invention.
[0075] Embodiments of the computational procedures employed in the
present invention are generally known among workers of skill in
fields related to the field of the present invention, including by
way of nonlimiting example, radiation physics, nuclear physics,
radiation chemistry, nuclear chemistry, environmental safety,
public health and safety, computer science, solid state and
semiconductor science, and the like.
[0076] The computations envisioned in the present invention include
steps such as a) inputting the digitized sample waveform from the
analog domain; b) processing the waveform; c) arriving at a
decision in which it is determined whether the input sample
waveform includes or contains components that are similar or
identical to at least one waveform resident in a library of stored
waveforms or spectra wherein the stored waveforms are those
characteristic of members of a set of target radionuclides or
threatening radionuclides; and d) outputting the result of the
decision. FIG. 1 provides a schematic representation of these
steps.
[0077] The processing step and the decision step include processes
such as a) a computational algorithm that prepares the digitized
input spectrum for further analysis and characterization; and b) a
computational algorithm whereby the prepared spectrum or waveform
is analyzed to provide the identities of any target radionuclides
any threatening radionuclides whose waveforms may be components of
the sample waveform. The algorithm in step b) may be any
computational procedure that analyzes a complex waveform into a set
of contributions originating from basic or orthogonal components.
Such computational procedures include, by way of nonlimiting
example, deconvolution computations to identify or evaluate
spectral components present; principal component analysis wherein
eigenvectors are arrived at which represent waveforms of reference
radionuclides as the orthogonal components present, and
corresponding eigenvalues represent a measure of the extent to
which the respective eigenvectors contribute; or neural network
analysis wherein previous analytic experience to which the
computational algorithm has been subjected contributes to
subsequent analyses that provide the component waveforms. If a
component waveform in the sample spectrum is similar or identical
to the waveform of a target radionuclide or a threatening
radionuclide then a positive decision has been reached. If no such
determination is reached, then a negative decision, indicating the
absence of characteristics of a target radionuclide or a
threatening radionuclide in the sample waveform is made. Any
equivalent computational algorithm may be used that accomplishes
the resolution of the sample waveform into components and
establishing whether a component is similar or identical to a
member of the library of spectra is envisioned to be within the
scope of the present invention. Such computational algorithms are
widely known to workers of skill in fields related to the field of
the present invention, including by way of nonlimiting example,
radiation physics, nuclear physics, radiation chemistry, nuclear
chemistry, environmental safety, public health and safety, computer
science, applied physics, applied mathematics, and the like.
[0078] The apparatus and methods of the present invention may be
employed to obtain the spectral waveform of a background sample,
that is, of a sample signal obtained when no subject occupies the
sample volume. Natural minerals and construction materials contain
radionuclides within them as naturally occurring components.
Frequently these background radionuclides are present at low
levels. Nevertheless in many physical locations in which the
apparatus of the present invention may be deployed, such as within
an edifice constructed of materials incorporating background
radionuclides, it is advantageous to accumulate a background sample
in order to account for the spectral components that constitute the
background radiation. Since the same components will be present
when a subject is in the sample volume during an actual assay, the
background spectrum may be employed to account for or neutralize
the background components in the sample spectrum. In this way the
net waveforms due to the subject in the sample volume are arrived
at. It is believed that this ability to compensate for background
waveform contributions to a sample spectrum offers an advantage of
the present invention not found in previous screening systems and
methods used to detect radionuclides.
[0079] A positive decision that a component waveform in the sample
spectrum is similar or identical to the waveform of a target
radionuclide or a threatening radionuclide effectively detects the
presence of such a radionuclide in the sample volume, and
identifies the offending radionuclide in the sample volume. One
response to a positive identification is to communicate the
presence of the target radionuclide in the sample volume, and to
communicate the identity of the target radionuclide in the sample
volume. This communication is made, for example, to an operator of
the installation that has deployed the apparatus of the invention,
or to appropriate enforcement authorities. An additional response
to a positive identification is to warn of the presence of a
threatening radionuclide in the sample volume, and to identify the
threatening radionuclide in the sample volume. Such a warning may
be, by way of nonlimiting example, a visual alarm to an operator or
person of authority, an audible alarm to an operator or person of
authority, rapid imposition of a physical restraint to impede the
movement of the subject in the sample volume that triggered the
positive decision, and the like.
[0080] The present invention additionally provides various methods
that include detection and identification of target radionuclides
or threatening radionuclides. In one aspect, a method is disclosed
for detecting a target radionuclide in a sample volume, or for
identifying a target radionuclide present in a sample volume, or
both, that includes the steps of [0081] a) juxtaposing the sample
volume and a detecting means that detects radiation emanating from
a radionuclide such that the detecting means detects radiation
emanating from the sample volume; [0082] b) detecting radiation
emanating from a radionuclide in the sample volume, wherein the
detecting means produces a sample signal characteristic of the
radionuclide; [0083] c) analyzing the sample signal produced in
step b) to identify its characteristics; d) determining whether
identified characteristics of the sample signal are similar or
identical to a signal characteristic of the target radionuclide;
whereby if the sample signal is determined to be so similar or
identical the target radionuclide is detected, and whereby
identifying the sample signal as being so similar or identical
identifies a target radionuclide in the sample volume.
[0084] In still another aspect, the invention discloses a method
for communicating the presence of a target radionuclide in a sample
volume, the identity of a target radionuclide in a sample volume,
or both, that includes the steps of [0085] a) juxtaposing the
sample volume and a detecting means that detects radiation
emanating from a radionuclide such that the detecting means detects
radiation emanating from the sample volume; and [0086] b) detecting
radiation emanating from a radionuclide in a sample volume, wherein
the detecting means produces a sample signal characteristic of the
radionuclide; [0087] c) analyzing the sample signal to identify its
characteristics; [0088] d) determining whether characteristics of
the analyzed sample signal are similar or identical to a signal
characteristic of a target radionuclide; and e) communicating a
determination that the characteristics of the sample signal are so
similar or identical; thereby communicating the presence of the
target radionuclide in the sample volume, or the identity of the
target radionuclide in the sample volume as having signal
characteristics similar or identical to the sample signal.
[0089] In yet a further aspect, the invention discloses a method
for warning of the presence and/or the identity of a threatening
radionuclide in a sample volume, that includes the steps of [0090]
a) juxtaposing the sample volume and a detecting means for
detecting radiation emanating from a radionuclide such that the
detecting means detects radiation emanating from the sample volume,
wherein the detecting means produces a sample signal characteristic
of the radionuclide; [0091] b) analyzing the sample signal to
identify its characteristics; [0092] c) comparing characteristics
of the analyzed sample signal to a set of signals, wherein each
member of the set is a signal that is characteristic of a
threatening radionuclide; [0093] d) determining that the
characteristics of the analyzed sample signal are similar or
identical to a signal characteristic of a threatening radionuclide;
and [0094] e) warning that the sample signal is determined to be so
similar or identical; thereby warning of the presence of the
threatening radionuclide in the sample volume, and/or warning of
the identity of a threatening radionuclide present in the sample
volume.
[0095] Approximately 1500 radionuclides are known at the present
time. It is possible to include many or all of these as reference
spectra of target radionuclides or threatening radionuclides. A
consequence of having a large number of reference waveforms in a
library resident in a storage device employed in the apparatus and
methods of the invention, however, is to increase the analysis time
required to make a decision. In addition, not all radionuclides are
currently considered to be target radionuclides or threatening
radionuclides. In the interests of providing apparatuses and
methods that may be implemented in the field, and that accomplish
the purpose of screening against components likely to be used in a
nuclear device, and that provide analysis times in actual usage
that are consistent with rapidity of analysis and convenience to
the public, certain nonlimiting embodiments of the present
invention restrict the identities of target radionuclides and
threatening radionuclides to a relatively small number. For
example, in one implementation of the present invention, a set of
target radionuclides and the set of threatening radionuclides may
include those shown in Table 1. TABLE-US-00001 TABLE I Potential
Target Radionuclides and Threatening Radionuclides Radionuclide
Half-life cesium-137 30 years cobalt-60 5.26 years strontium-90
28.1 years iridium-192 74.2 days americium-241 458 years
manganese-54 303 days iron-55 2.6 years iodine-125 60 days
iodine-130 12.4 hours iodine-131 8.05 days molybdenum 99 67 hours
technetium-99m 6.0 hours uranium-235 7.03 .times. 10.sup.8 years
uranium-238 4.46 .times. 10.sup.9 years transuranium radionuclides
including those of plutonium and californium a plutonium-beryllium
source radioactive decay products of uranium
[0096] In other embodiments, fewer radionuclides chosen from among
this set may be used; and in still other embodiments a different
set of target radionuclides or threatening radionuclides may be
used, in which certain members of the above set are substituted by
others, or still others are added to the set. Choices of which
radionuclides to include are made by appropriate authorities in
fields related to the field of the present invention, including by
way of nonlimiting example radiation physics, nuclear physics,
radiation chemistry, nuclear chemistry, environmental safety,
public health and safety, and the like. Any reference set defined
by appropriate authorities is envisioned as being within the scope
of the present invention.
[0097] A consideration in implementing an apparatus and methods of
the present invention is the total elapsed time required for
analysis. A shorter analysis time increases the acceptability of
screening, and convenience, to the screened subject. Implementation
of short analysis times is related to factors such as the
sensitivity of a detector, amplification of a signal, efficiency of
a decision-making algorithm, and the number of reference spectra,
among others. Nonlimiting examples of total elapsed times for
analysis may be about 10 seconds, or about 7 seconds, or about 5
seconds, or about 3 seconds, or about 2 seconds, or about 1 second,
or about 0.75 second, or about 0.5 second, or about 0.4 second, or
about 0.3 second, or about 0.2 second, or about 0.1 second, or even
shorter total elapsed times. A worker of skill in fields related to
the field of the present invention has general understanding of
factors such as these, and of ways in which to optimize the
analysis time for deployment. These fields include, by way of
nonlimiting example, radiation physics, nuclear physics, radiation
chemistry, nuclear chemistry, environmental safety, public health
and safety, computer science, applied physics, applied mathematics,
and the like. Any elapsed time interval that provides convenient,
acceptable screening procedures is understood to be within the
scope of the present invention.
[0098] A nonlimiting example of a housing incorporating a detector
employed in the apparatus of the invention is shown in FIG. 2. The
housing has a diameter of approximately 4.5 inches and a length of
approximately 17 inches. At the time the photograph was taken, the
housing contained a Nal detector. The housing as shown, and similar
embodiments of a housing, can accommodate at least three detectors;
nonlimiting examples of which include a Nal detector, a
cadmium-zinc-telluride detector, and a neutron detector based
either on BF.sub.3 or He-3 as the active element. The cable leading
from the housing out of the photograph to the left is an example of
an interacting means whereby the detectors interact with an analog
signal analysis module. The latter module is at a remote location
with respect to the detector.
EXAMPLES
[0099] In the following examples, background and samples were
assayed in an apparatus of the invention using a detector having a
Gamma 8000 Nat crystal (Amptek, Inc., Bedford, Mass.), a
cadmium-zinc-telluride detector (Amptek), and a model 8000A
multichannel analyzer manufactured by Amptek. The computations were
implemented on a Dell Model 4100 Laptop computer. The distance
between the detector and the sample was either 2 feet (providing a
strong signal), 6 feet (providing a medium signal), or 10 feet
(providing a weak signal). Three different sources were used as the
samples in these Examples: a Co-60 source (441.4 microCi), a Cs-137
source (4.107 rmlliCi), and an Am-241 source (17.426 milliCi), all
of which were obtained from New England Nuclear, Boston, Mass. In
some cases, the Co-60 or the Cs-137 was shielded from the detector
by a 1 inch shield of lead. The Am-241 was never shielded in these
experiments. In all experiments the settings used were GAIN 2 and
THRESHOLD 13.
Example 1
4 Second Elapsed Accumulation Time
[0100] In this example, separate waveforms for Am-241, unshielded,
and Co-60, shielded are shown, as well as the waveform obtained
when both sources were in the sample volume. FIG. 3 shows the
waveforms obtained. Panel A provides the multichannel analyzer
output of a background count. It is seen that the background is
very low. Panel B provides the waveform for Am-241 when the
distance between the detector and the source was 10 feet. Table 2
shows the channel and count number obtained for the channel having
the maximum count for Am-241 at all three distances. TABLE-US-00002
TABLE 2 Am-241, 4 second elapsed time Distance, feet Channel*
Counts 10 49 57 6 47 128 2 45 10047 *The channel number depends on
specific calibration in each run.
[0101] Panel C shows a waveform obtained with Co-60 shielded by 1
inch of lead at 4 sec when the distance between the detector and
the source was 6 feet. Table 3 provides results for shielded Co-60
at all three distances tested, for the channels having a maximal
reading in a peak region. TABLE-US-00003 TABLE 3 Co-60, shielded by
i inch of lead, 4 second elapsed time Distance, feet Channel*
Counts Channel* Counts 10 134 23 863 8 6 115 33 881 15 2 168 106
864 79 *The channel number depends on specific calibration in each
run.
[0102] Panel D shows the results obtained when both shielded Co-60
and unshielded Am-241 are used as the source, at a distance of 6
feet. It is seen that the waveform obtained (Panel D) represents
the expected superposition of the waveforms of the two
radionuclides obtained when separate (Panels B and C).
Example 2
0.5 Second Elapsed Accumulation Time
[0103] FIG. 4 presents the results of selected experiments using a
0.5 sec accumulation time. Panel A presents a background reading,
showing very low counts or none during the time elapsed. Panels B
and C show waveforms accumulated for Cs-137 under different
conditions. In Panel B, the source was shielded by 1 inch of lead,
and the signal was accumulated at a distance of 6 feet. In Panel C
the same source was unshielded, and the spectrum obtained at the
same distance, 6 feet. In Panel D, the source contained three
radionuclides in unshielded configuration, and was obtained at a
distance of 6 feet. The separate waveforms corresponding to the
sources used here appear in FIG. 3, Panel B (Am-241), FIG. 3, Panel
C (Co-60), and FIG. 4, Panel C (Cs-137). The resulting waveform,
shown in Panel D, includes contributions expected from each
separate component.
Example 3
Warning of a Threatening Radionuclide at a Highway Interchange
[0104] An apparatus of the invention is installed in such a way as
to interrogate motor vehicles at an interchange resembling a toll
booth on a highway. The detector is mounted adjacent to the lane
such that it is approximately 1-2 feet from the expected closest
surface of the vehicle as it passes. A gate stops the vehicle
momentarily while the detector accumulates the radiation spectrum
from the vehicle. The digital domain of the apparatus is programmed
with a neural network algorithm for identifying threatening
radionuclides. If a threatening radionuclide is not detected the
toll gate lifts and the vehicle exits the lane. If a threatening
radionuclide is identified, a warning light and a warning horn are
activated, and a security officer arrives to evaluate the
situation.
Example 4
Warning of a Threatening Radionuclide at an Airport Security
Check
[0105] An apparatus of the invention is installed at an airport
security installation as part of the inspection of individual
persons and hand-carried baggage. An individual together with
his/her personal effects as carry-on baggage stands momentarily
before a detector of the apparatus, at a distance of 1-2 feet from
it. The digital domain of the apparatus is programmed with a
principal component algorithm for identifying threatening
radionuclides. If a threatening radionuclide is not detected the
individual may pass through the security installation. If a
threatening radionuclide is identified, a warning light and a
portable alarm device carried by a security officer are activated,
and the security officer summons the individual to evaluate the
situation.
Example 5
Warning of a Threatening Radionuclide at a Shipping Facility
[0106] An apparatus of the invention is installed at a shipping
terminal in such a way that shipping containers pass directly
before, or under, one or more detector modules as they are
offloaded from a vessel. The detector modules interact with the
remainder of the apparatus by solid connectors or by means of
electromagnetic radiation transmission. The digital domain of the
apparatus is programmed with a deconvolution algorithm for
identifying threatening radionuclides. If a threatening
radionuclide is not detected the container may pass through the
screening installation. If a threatening radionuclide is
identified, a warning light, an warning sound, and a portable alarm
device carried by a security officer are activated, and the
security officer evaluates the situation.
[0107] The Examples demonstrate the ability of the apparatus and
methods of the present invention to detect and identify target
radionuclides and threatening radionuclides under field conditions.
The apparatus and methods are useful at short accumulation times,
permitting use in high throughput environments. The detection and
identification of target radionuclides and threatening
radionuclides communicates a positive determination to an operator
or appropriate authorities, and provides a warning to an operator
or appropriate authorities.
* * * * *