Bulletin of the American Physical Society
APS March Meeting 2011
Volume 56, Number 1
Monday–Friday, March 21–25, 2011; Dallas, Texas
Session Q5: The Physics of Confronting Weapons of Mass Destruction: Chemical, Biological and Nuclear |
Hide Abstracts |
Sponsoring Units: FIAP Chair: Jay Davis, Hertz Foundation Room: Ballroom C1 |
Wednesday, March 23, 2011 11:15AM - 11:51AM |
Q5.00001: Physics in the Confrontation of Nuclear Weapons Invited Speaker: Had the detonations on 9/11 involved nuclear explosives rather than jet fuel the number of deaths and the costs would have been multiplied by 100 or 1,000. This talk will briefly describe the nuclear threat and then focus on the technologies, both extant and evolving, for the detection and interdiction of clandestine trafficking of nuclear weapons and nuclear and radiological material. The methods vary from passive detection of heat, gamma radiation, neutrons, or other signatures from nuclear material, through radiological approaches to examine contents of vehicles and cargo containers, to active interrogation concepts that are under development. All of these methods have major physics components ranging from simple gamma ray detection as learned in a senior undergraduate lab to the latest ideas in muon production and acceleration. [Preview Abstract] |
Wednesday, March 23, 2011 11:51AM - 12:27PM |
Q5.00002: Discrimination and classification of bio-aerosol particles using optical spectroscopy and scattering Invited Speaker: For more than a decade now, there has been significant emphasis for development of sensors of agent aerosols, especially for biological warfare (BW) agents. During this period, the Naval Research Laboratory (NRL) and other labs have explored the application of optical and spectroscopic methods relevant to biological composition discrimination to aerosol particle characterization. I will first briefly attempt to establish the connection between sensor performance metrics which are statistically determined, and aerosol particle measurements through the use of computational models, and also describe the challenge of ambient background characterization that would be needed to establish more reliable and deterministic sensor performance predictions. Greater attention will then be devoted to a discussion of basic particle properties and their measurement. The NRL effort has adopted an approach based on direct measurements on individual particles, principally of elastic scatter and laser-induced fluorescence (LIF), rather than populations of particles. The development of a LIF instrument using two sequential excitation wavelengths to detect fluorescence in discrete spectral bands will be described. Using this instrument, spectral characteristics of particles from a variety of biological materials including BW agent surrogates, as well as other ``calibration'' particles and some known ambient air constituents will be discussed in terms of the dependence of optical signatures on aerosol particle composition, size and incident laser fluence. Comparison of scattering and emission measurements from particles composed of widely different taxa, as well as from similar species under different growth conditions highlight the difficulties of establishing ground truth for complex biological material compositions. One aspect that is anticipated to provide greater insight to this type of particle classification capability is the development of a fundamental computational model of fluorescent emission for a particle of known composition but arbitrary size and shape. Finally if time permits, I will review the recent development and use of a 40 MHz mode-locked 524 nm laser source to evaluate the utility of sub-picosecond excitation of fluorescence with 2-photon absorption in biological aerosols. [Preview Abstract] |
Wednesday, March 23, 2011 12:27PM - 1:03PM |
Q5.00003: Minimizing the bioterrorist threat: Fear, fancy, folly, and physics Invited Speaker: There can be little doubt that a bioterrorist attack represents one of the most significant dangers facing the Nation today. It is cheap, relatively easy to use, and can produce huge casualties and significant financial losses. Because of its apparent simplicity, there has been a great amount of attention directed towards developing means for early detection of an attack in progress. Most developmental funding for protective strategies comes from the Federal government: DoD is focused on protecting the military (personnel and facilities) whereas DoHS is most concerned with civilian response (police, triage, epidemiology, cure). Associated with such activities are some pretty amazing ideas both concerning the threat and means to detect its presence. These include the belief that certain bioterrorist attacks could equal the consequences of a nuclear weapon, that crop dusters with the proper agents could wipe out a city, that if it ``glows'' (i. e. is fluorescent) it must be an agent, or even that gravitational forces are actually far greater than believed. From the early warning side of things, the huge costs associated with a false positive call have resulted in the generally recognized need to identify before any alarm is triggered. Some consequences of this strategy have been the development of so-called smart chips and even handheld mass spectrometers! A brief review of some of these devices and the physics required for their success is discussed. An approach based upon some simple features of inverse scattering theory is proposed whereby identification may be unnecessary. [Preview Abstract] |
Wednesday, March 23, 2011 1:03PM - 1:39PM |
Q5.00004: Physics and National Security: The Spectrum of Opportunities Invited Speaker: Physicists reflexively tend to approach their role in addressing national security problems by reaching for technologies and inventing devices or systems. While this is appropriate, the space for contribution is much larger. The application of technology is frequently constrained by doctrinal, operational, financial, and logistic constraints, not to mention those of security. The speaker, who has played a role in technology development, field operations, advisory processes, and policy considerations will discuss the role physicists can have in definition of the threat space, creation and assessment of technologies needed, and helping with response and recovery. In particular, he will address the opportunities and risks for both academic and industrial physicists in trying to assist in these matters, i.e., when in career to address such problems, what are the obstacles or consequences, and when do you know you have contributed? [Preview Abstract] |
Wednesday, March 23, 2011 1:39PM - 2:15PM |
Q5.00005: Detecting Chemical Weapons: Threats, Requirements, Solutions, and Future Challenges Invited Speaker: Although chemicals have been reportedly used as weapons for thousands of years, it was not until 1915 at Ypres, France that an industrial chemical, chlorine, was used in World War I as an offensive weapon in significant quantity, causing mass casualties. From that point until today the development, detection, production and protection from chemical weapons has be an organized endeavor of many of the world's armed forces and in more recent times, non-governmental terrorist organizations. The number of Chemical Warfare Agents (CWAs) has steadily increased as research into more toxic substances continued for most of the 20$^{\rm th}$ century. Today there are over 70 substances including harassing agents like tear gas, incapacitating agents, and lethal agents like blister, blood, chocking, and nerve agents. The requirements for detecting chemical weapons vary depending on the context in which they are encountered and the concept of operation of the organization deploying the detection equipment. The US DoD, for example, has as a requirement, that US forces be able to continue their mission, even in the event of a chemical attack. This places stringent requirements on detection equipment. It must be lightweight ($<$2 lbs), detect a large array of chemical warfare agents and toxic industrial chemicals, detect and warn at concentration levels and time duration to prevent acute health effects, meet military ruggedness specifications and work over a wide range of temperature and humidity, and have a very high probability of detection with a similarly low probability of false positives. The current technology of choice to meet these stringent requirements is Ion Mobility Spectrometry. Many technologies are capable of detecting chemicals at the trace levels required and have been extensively developed for this application, including, but not limited to: mass spectroscopy, IR spectroscopy, RAMAN spectroscopy, MEMs micro-cantilever sensors, surface acoustic wave sensors, differential mobility spectrometry, and amplifying fluorescence polymers. In the future the requirements for detection equipment will continue to become even more stringent. The continuing increase in the sheer number of threats that will need to be detected, the development of binary agents requiring that even the precursor chemicals be detected, the development of new types of agents unlike any of the current chemistries, and the expansion of the list of toxic industrial chemical will require new techniques with higher specificity and more sensitivity. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700