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It's been a while since I posted, and I'm going to go retro on this one. I had misplaced where I had put the source for this one and so can only post it now (I only had the PDF). I did this in the winter term of my first year at university. I had no idea how to use the library, I had no idea how to do citations, I had no idea how to write a research paper. But I ended up, I found out later, writing a 3rd year independent research paper (good enough for an honours project in Integrated Science at Carleton apparently, but I didn't know that at the time). I was asked to do it by a professor as a prelude to summer employment working on the CRIPT project as a research assistant. A gig that ran full time in the summers and a part time (mostly, sometimes more) through the school year until the end of November 2012, when the project started to wrap up and my contract was terminated. It was a good run, and I learned an amazing amount. I also feel privileged to have been able to have such an important role on such a huge project as an undergraduate student (mind you, it was my electronics and software experience they used, but still). I continue to volunteer on the project and am doing some additional volunteer work on another project studying the flux of horizontal cosmic ray muons leveraging the work I did on CRIPT (for developing a detector that can image the inside of nuclear reactors, for instance that have melted down, without having to actually get near them... naturally occurring muons are amazing particles!). Since the project proper has wrapped up and the new detector is still in the proposal stage, I decided to take a Teacher's Assistant position in the PHYS1004 class in the winter term (the money will help quite a bit even though it's not much). Anyway, this was submitted on April 30th, 2010. Oh, and I got an A- on it... :)
The Use of Cosmic Ray Muon Tomography in the
Detection of Concealed High-Z Materials
I. INTRODUCTION
A. The need for screening
It is becoming ever more important to monitor the flow of goods and people as a deterrent against state, criminal, or ideological organizations that may wish to wage war or cause serious disruption through the use of various asymmetric weapons systems within the territories we wish to consider secure. To that end, increasing surveillance and intrusive inspections have been implemented at points where the greatest risk exists, for instance at airports and border crossings. For an effective deterrent, all traffic through these key points of commerce and travel especially, as well as the appropriate measures for points between, require 100% screening to be maximally secure. For historic and economic reasons, this strategy of complete coverage presents an extreme challenge to even the most affluent and security conscious of societies. Furthermore, any onerous impediment to the efficient movement of goods and people elicits an economic cost of its own that can destroy the very prosperity that such security measures wish to protect.
While it can be argued that the smuggling of conventional weapons poses the greatest chance of occurring and resulting in harm being inflicted through their use, all but the largest of instances of such smuggling into otherwise stable countries are dwarfed by the already existent availability of these items within those countries. Where the national government of a country needs to protect its citizens against all forms of weapons smuggling, it has a special obligation to prevent the use of chemical, biological, radiological, and nuclear (CBRN) weapons against its population, infrastructure, services, and legitimate foreign interests: “Asymmetric CBR threats provide an adversary with significant political and force multiplier advantages, such as disruption of operational tempo, interruption/denial of access to critical infrastructure and the promulgation of fear and uncertainty in military and civilian populations. [...] Proliferation will continue to dramatically increase the threat from the use of CBR agents by states or terrorist organizations against unprotected civilian populations. Proliferation also poses an asymmetric threat against non-combatants outside the immediate theatre of conflict, including Canadians at home.”1 As such, most functional nations have embarked on integrated strategies to minimize the chances of CBRN related incidents. In general, those efforts can be categorized in five ways: supporting or directing the improvement of foreign CBRN control, detection, and enforcement; border CBRN detection equipment and domestic law enforcement training; the securing of legitimate CBRN materials within the country’s borders; improved intelligence operations to detect potential smuggling operations before they occur; and various domestic and international research and development project to improve overall control and detection capabilities.2
Furthermore, of the CBRN threats, there are emergency measures and possible mitigation that can be taken to minimize the impact to the population and infrastructure of a successful attack with chemical, biological, or radiological weapons; however, the damage that would be inflicted should a nuclear device be detonated in a populated area would be devastating beyond measure to both the fabric and spirit of the country, its operation, and its people. Such results make special nuclear materials3 (as could be used in a nuclear bomb) particularly attractive targets for terrorists4 (“independent” or state sponsored): “Nuclear smuggling is an increasing concern for international security because creating a viable nuclear weapon only requires several kilos of plutonium or highly enriched uranium. The International Atomic Energy Agency has documented 18 cases of theft of nuclear [weapon grade] materials within the last decade, and probably more instances have occurred without report. This is especially prevalent within the former Soviet bloc, where large amounts of nuclear materials are insecurely guarded and inventories are often faultily kept.”5
Of particular concern is the realization that the view, held since World War II3, that the effort required to build a nuclear weapon was prohibitive, is no longer valid. This opinion had been based on the American experience of creating two small nuclear weapons, but it is now widely accepted that the expertise and technical capability to build a viable nuclear weapon is no longer the exclusive purview of large, economically advanced nation-states. In fact, the knowledge and infrastructure required is potentially within reach of any well-organized and funded group with sufficient long-term determination and resourcefulness: “The only real technological barrier to the clandestine construction of nuclear weapons is access to fissionable material itself. There is a growing black market for this material, and eventually demand will result in enough material reaching as-yet unidentified buyers to produce a nuclear weapon”3. In addition to the smuggling of processed special nuclear materials, given that uranium is roughly 40 times more prevalent in the Earth’s crust than is silver6, the smuggling of uranium ore or low quality extracted uranium from such ore is also a more likely possibility.
While it is widely acknowledged that “most known interdictions of weapons-useable nuclear materials have resulted from police investigations rather than by radiation detection equipment installed at border crossings”2, the asymmetric nature of the threat calls for exceptional measures in the effective detection of smuggled special nuclear and radiological materials that might make it past the intelligence operations to a port of entry into the country. Per the U.S. Container Security Initiative Strategic Plan: 2006-2011, “the cost to the U.S. Economy resulting from port closures due to the discovery or detonation of a weapon of mass destruction or effect (WMD/E) would be enormous. In October 2002, Booz, Allen and Hamilton reported that a 12-day closure required to locate an undetonated terrorist weapon at one U.S. seaport would cost approximately $58 billion. In May 2002, the Brookings Institution estimated that costs associated with U.S. port closures resulting from a detonated WMD/E could amount to $1 trillion, assuming a prolonged economic slump due to an enduring change in our ability to trade.”7 While this is a U.S. figure, it can be scaled appropriately to reflect the impact of such an event on any trading nation, or the domino effect such an act would have on global commerce if it happened anywhere.
( This part of the paper is here... )
D. Outline of Thesis
Because of the sensitivity of Passive Muon Tomography (PMT) systems to high-Z materials (versus lighter elements) they are a much more targeted solution than more indiscriminate imaging systems, and the lack of an active radiation source eliminates the potential health concerns associated with x-ray and gamma ray imaging systems. While PMT systems only address a particular class of risk, specifically the threat posed by the trafficking of special nuclear materials that could form the basis for a bomb or large well-shielded shipments of radionuclides that could be used in a “dispersal” device, the asymmetric nature of the threat justifies the commercialization of this technology to compensate for the serious limitations of existing technologies in this area of detection. Carleton University’s proposal to use large-area drift chambers for muon detection will result in a device that will provide excellent spacial and temporal resolution with very cost effective readout electronics and data processing requirements; however, the initial requirement for a flowing gas in the first generation solution presents a negative offset through higher infrastructure and ongoing maintenance costs that would need to be mitigated as part of a widespread deployment of this particular solution.
( The rest of the paper is here... )
VI. Conclusion
Passive cosmic ray muon tomography systems present an excellent solution to the issue of deterring and detecting the trafficking in nuclear and radiological materials – in the first case through direct detection of high-Z materials, and in the second case, being able to detect high-Z shielding that might be hiding lower-Z radiological materials. The system further distinguishes itself by not introducing any new sources of radiation, thus sidestepping any potential health or safety concerns from the public or business. Carleton University’s proposed drift chamber muon detectors build upon decades of experience in implementing high resolution muon analysis systems, and can be used to determine to a high degree of accuracy both angular and momentum data on the muons passing through a detector system for analysis by the tomographic software. The low cost of readout electronics compensates for the higher cost due to the requirement for gas-filled chambers, and will result in a competitive solution for field-deployable systems.
( And the bibliography is here... )
Detection of Concealed High-Z Materials
I. INTRODUCTION
A. The need for screening
It is becoming ever more important to monitor the flow of goods and people as a deterrent against state, criminal, or ideological organizations that may wish to wage war or cause serious disruption through the use of various asymmetric weapons systems within the territories we wish to consider secure. To that end, increasing surveillance and intrusive inspections have been implemented at points where the greatest risk exists, for instance at airports and border crossings. For an effective deterrent, all traffic through these key points of commerce and travel especially, as well as the appropriate measures for points between, require 100% screening to be maximally secure. For historic and economic reasons, this strategy of complete coverage presents an extreme challenge to even the most affluent and security conscious of societies. Furthermore, any onerous impediment to the efficient movement of goods and people elicits an economic cost of its own that can destroy the very prosperity that such security measures wish to protect.
While it can be argued that the smuggling of conventional weapons poses the greatest chance of occurring and resulting in harm being inflicted through their use, all but the largest of instances of such smuggling into otherwise stable countries are dwarfed by the already existent availability of these items within those countries. Where the national government of a country needs to protect its citizens against all forms of weapons smuggling, it has a special obligation to prevent the use of chemical, biological, radiological, and nuclear (CBRN) weapons against its population, infrastructure, services, and legitimate foreign interests: “Asymmetric CBR threats provide an adversary with significant political and force multiplier advantages, such as disruption of operational tempo, interruption/denial of access to critical infrastructure and the promulgation of fear and uncertainty in military and civilian populations. [...] Proliferation will continue to dramatically increase the threat from the use of CBR agents by states or terrorist organizations against unprotected civilian populations. Proliferation also poses an asymmetric threat against non-combatants outside the immediate theatre of conflict, including Canadians at home.”1 As such, most functional nations have embarked on integrated strategies to minimize the chances of CBRN related incidents. In general, those efforts can be categorized in five ways: supporting or directing the improvement of foreign CBRN control, detection, and enforcement; border CBRN detection equipment and domestic law enforcement training; the securing of legitimate CBRN materials within the country’s borders; improved intelligence operations to detect potential smuggling operations before they occur; and various domestic and international research and development project to improve overall control and detection capabilities.2
Furthermore, of the CBRN threats, there are emergency measures and possible mitigation that can be taken to minimize the impact to the population and infrastructure of a successful attack with chemical, biological, or radiological weapons; however, the damage that would be inflicted should a nuclear device be detonated in a populated area would be devastating beyond measure to both the fabric and spirit of the country, its operation, and its people. Such results make special nuclear materials3 (as could be used in a nuclear bomb) particularly attractive targets for terrorists4 (“independent” or state sponsored): “Nuclear smuggling is an increasing concern for international security because creating a viable nuclear weapon only requires several kilos of plutonium or highly enriched uranium. The International Atomic Energy Agency has documented 18 cases of theft of nuclear [weapon grade] materials within the last decade, and probably more instances have occurred without report. This is especially prevalent within the former Soviet bloc, where large amounts of nuclear materials are insecurely guarded and inventories are often faultily kept.”5
Of particular concern is the realization that the view, held since World War II3, that the effort required to build a nuclear weapon was prohibitive, is no longer valid. This opinion had been based on the American experience of creating two small nuclear weapons, but it is now widely accepted that the expertise and technical capability to build a viable nuclear weapon is no longer the exclusive purview of large, economically advanced nation-states. In fact, the knowledge and infrastructure required is potentially within reach of any well-organized and funded group with sufficient long-term determination and resourcefulness: “The only real technological barrier to the clandestine construction of nuclear weapons is access to fissionable material itself. There is a growing black market for this material, and eventually demand will result in enough material reaching as-yet unidentified buyers to produce a nuclear weapon”3. In addition to the smuggling of processed special nuclear materials, given that uranium is roughly 40 times more prevalent in the Earth’s crust than is silver6, the smuggling of uranium ore or low quality extracted uranium from such ore is also a more likely possibility.
While it is widely acknowledged that “most known interdictions of weapons-useable nuclear materials have resulted from police investigations rather than by radiation detection equipment installed at border crossings”2, the asymmetric nature of the threat calls for exceptional measures in the effective detection of smuggled special nuclear and radiological materials that might make it past the intelligence operations to a port of entry into the country. Per the U.S. Container Security Initiative Strategic Plan: 2006-2011, “the cost to the U.S. Economy resulting from port closures due to the discovery or detonation of a weapon of mass destruction or effect (WMD/E) would be enormous. In October 2002, Booz, Allen and Hamilton reported that a 12-day closure required to locate an undetonated terrorist weapon at one U.S. seaport would cost approximately $58 billion. In May 2002, the Brookings Institution estimated that costs associated with U.S. port closures resulting from a detonated WMD/E could amount to $1 trillion, assuming a prolonged economic slump due to an enduring change in our ability to trade.”7 While this is a U.S. figure, it can be scaled appropriately to reflect the impact of such an event on any trading nation, or the domino effect such an act would have on global commerce if it happened anywhere.
( This part of the paper is here... )
D. Outline of Thesis
Because of the sensitivity of Passive Muon Tomography (PMT) systems to high-Z materials (versus lighter elements) they are a much more targeted solution than more indiscriminate imaging systems, and the lack of an active radiation source eliminates the potential health concerns associated with x-ray and gamma ray imaging systems. While PMT systems only address a particular class of risk, specifically the threat posed by the trafficking of special nuclear materials that could form the basis for a bomb or large well-shielded shipments of radionuclides that could be used in a “dispersal” device, the asymmetric nature of the threat justifies the commercialization of this technology to compensate for the serious limitations of existing technologies in this area of detection. Carleton University’s proposal to use large-area drift chambers for muon detection will result in a device that will provide excellent spacial and temporal resolution with very cost effective readout electronics and data processing requirements; however, the initial requirement for a flowing gas in the first generation solution presents a negative offset through higher infrastructure and ongoing maintenance costs that would need to be mitigated as part of a widespread deployment of this particular solution.
( The rest of the paper is here... )
VI. Conclusion
Passive cosmic ray muon tomography systems present an excellent solution to the issue of deterring and detecting the trafficking in nuclear and radiological materials – in the first case through direct detection of high-Z materials, and in the second case, being able to detect high-Z shielding that might be hiding lower-Z radiological materials. The system further distinguishes itself by not introducing any new sources of radiation, thus sidestepping any potential health or safety concerns from the public or business. Carleton University’s proposed drift chamber muon detectors build upon decades of experience in implementing high resolution muon analysis systems, and can be used to determine to a high degree of accuracy both angular and momentum data on the muons passing through a detector system for analysis by the tomographic software. The low cost of readout electronics compensates for the higher cost due to the requirement for gas-filled chambers, and will result in a competitive solution for field-deployable systems.
( And the bibliography is here... )
