Bulletin of the American Physical Society
2006 Division of Nuclear Physics Annual Meeting
Wednesday–Saturday, October 25–28, 2006; Nashville, Tennessee
Session GB: Mini-symposium on Nuclear Physics and National Security |
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Sponsoring Units: DNP Chair: Mark Riley, Florida State University Room: Gaylord Opryland Tennessee A |
Saturday, October 28, 2006 9:00AM - 9:36AM |
GB.00001: Nuclear Security in the 21$^{st}$ Century Invited Speaker: Nuclear security has been a priority for the United States, starting in the 1940s with the secret cities of the Manhattan Project. In the 1970s, the United States placed radiation monitoring equipment at nuclear facilities to detect nuclear material diversion. Following the breakup of the Soviet Union, cooperative Russian/U.S. programs were launched in Russia to secure the estimated 600+ metric tons of fissionable materials against diversion (Materials Protection, Control, and Accountability -- MPC{\&}A). Furthermore, separate programs were initiated to detect nuclear materials at the country's borders in the event that these materials had been stolen (Second Line of Defense - SLD). In the 2000s, new programs have been put in place in the United States for radiation detection, and research is being funded for more advanced systems. This talk will briefly touch on the history of nuclear security and then focus on some recent research efforts in radiation detection. Specifically, a new breed of radiation monitors will be examined along with the concept of sensor networks. [Preview Abstract] |
Saturday, October 28, 2006 9:36AM - 9:48AM |
GB.00002: Measurement Challenges in International Agreements John Luke Making measurements in support of international agreements can pose many challenges both from a policy and science point of view. Policy issues may arise because physics measurements made in the area of arms control or disarmament may be deemed too intrusive since they could possibly reveal sensitive information about the material that is being interrogated. Therefore, agreements must include a framework for safeguarding against the potential release of this information. Most of the scientific issues center around the fact that it is desirable to make high quality measurements without any operator interaction. This leads to the development of instrumentation and software that are very stable and robust. Due to different concerns, policy and science priorities may be at odds with one another. Therefore, it is the scientist’s challenge - in this field - to keep policy makers informed by conveying what is technically possible and what is not in a manner that is easily understood and also negotiable. In this paper we will discuss some of the technology that has been developed to address some of these challenges in various international and model agreements. We will discuss the principle of informational barrier used in these measurement technologies to safeguard the release of sensitive information. We will also discuss some of the pitfalls that may arise when policy is ill informed about the physical constraints in the making of measurements of nuclear materials. [Preview Abstract] |
Saturday, October 28, 2006 9:48AM - 10:00AM |
GB.00003: Nuclear Physics for National Security Douglass Mayo Being a nuclear physicist and working at a national laboratory provides many opportunities to ply one's skills in support of national security and the benefit of all mankind. Over the last 40 years, Los Alamos National Laboratory has been pioneering the field of Domestic and International Safeguards through the research and development of instrumentation and systems used to monitor nuclear materials and nuclear facilities. With a projected increase in the use of nuclear energy, effective systems must be designed to reduce the possibility that nuclear materials may be diverted for used in weapons. The recent focus has been the many applications of radiation detection used for safeguarding nuclear material and to support Homeland Security. There is a critical need for trained nuclear scientists who can understand and overcome measurement complexities, combinations of multiple sensor inputs, data reduction, and automated analysis for these applications. This talk will focus on the opportunities and experiences afforded physicists in the support of national security, beyond the weapons program and travel to interesting locales. [Preview Abstract] |
Saturday, October 28, 2006 10:00AM - 10:12AM |
GB.00004: Mapping Isotopic Distributions in Cargo to Detect SNM and its Configuration Dennis P. McNabb Plans to demonstrate isotope-specific imaging using nuclear resonance fluorescence (NRF) \textit{via} tunable quasi-monochromatic (Thomson) photon sources, while at the same time providing a conventional radiograph of the bulk matter distribution, will be discussed. The implementation of NRF-based imaging depends strongly on the nature of the X-ray illumination source [1]. Monte Carlo simulations used to study source properties to study the sensitivity of the technique in thick cargos for different photon source characteristics will be presented. Thomson or inverse-Compton scattering of laser photons from beams of relativistic electrons produce beams that are quasi-monochromatic, highly collimated and have been shown to scale in spectral brightness as the square of the X-ray energy [2]. A source with a larger fraction of the photons in the region of the resonance energy will result in higher signal-to-noise ratios with considerably less dose than conventional Bremsstrahlung-based machines. The ability to make an isotope-specific image has the potential to transform the special nuclear material detection problem from simply identifying high optical depth cargo or high-Z material, to unambiguous detection and verification of the specific contraband material. The high spectral brightness of this technology significantly reduces the radiological dose required for detection and largely eliminates artifacts due to small-angle Compton scattering. In collaboration with C.P.J Barty, F.V. Hartemann, J. Pruet, S.G. Anderson, P.D. Barnes, D.J. Gibson, C.A. Hagmann, J.E. Hernandez, M.S. Johnson, I. Jovanovic, M. J. Messerly, E.B. Norman, M.Y. Shverdin, C.W. Siders, and A.M. Tremaine, Lawrence Livermore National Laboratory. [1] J. Pruet, D.P. McNabb, C.A. Hagmann, F.V. Hartemann, and C.P.J. Barty J. Appl. Phys., in press (2006). [2] F.V. Hartemann et al., PRLSTAB 8, 100702 (2005). [Preview Abstract] |
Saturday, October 28, 2006 10:12AM - 10:24AM |
GB.00005: Detection of fissionable material in cargo containers using active neutron interrogation Jennifer Church Roughly 6 million cargo containers will be shipped to U.S. seaports in a single year, each container carrying up to 30 tons of freight in varied configurations. Highly enriched uranium and other fissionable material concealed inside these containers is a challenge for existing portal monitors, due in part to the attenuation of signals in the cargo. A system is currently being developed to overcome these challenges without slowing the flow of commerce through the port, keeping the likelihood of false-negative and false- positive detections to a minimum. The technique utilizes a neutron beam to induce fission, and a wall of plastic scintillators to detect subsequent delayed high-energy $\gamma$- rays after $\beta$-decay of the fission products\footnote {E.B.\,Norman {\it{et al.}}, Nucl. Instr. Methods Phys. Res. A, {\bf{521}}, 608 (2004)}. Decay curves utilizing these delayed $\gamma$-rays with energies above 3 MeV are an efficient diagnostic. New experimental work using a 3-7 MeV broad spectrum neutron source will be presented and compared to simulations and past experimental results. This work is performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory contract No. W-7405-Eng-4, UCRL-ABS-219231. [Preview Abstract] |
Saturday, October 28, 2006 10:24AM - 10:36AM |
GB.00006: Inherent Challenges of Mobile Radiation Detection David Campbell The need for effective mobile detection systems is paramount when searching for rogue sources of radiation. However, once a detector begins to move, it encounters a dynamic environment where ambient radiation levels vary dramatically. Some of the challenges inherent to mobile radiation detection will be detailed along with some methods for addressing them. [Preview Abstract] |
Saturday, October 28, 2006 10:36AM - 10:48AM |
GB.00007: Physical Limitations of Neutron-Based Explosives Detection Systems Phillip Womble, Alexander Barzilov, Jon Paschal, Lindsay Hopper, Ryan Moore, Jeremy Board, Eric Houchins, Ian Rice, Joseph Howard Recent events in Madrid and London have once again focused attention on the problem of threat detection using elemental analysis. Neutron-based systems are utilized to perform bulk chemical analysis due to their high chemical specificity and their fairly rapid response time. While there are many acronyms for these systems, their working principle is typically to interrogate the sample with a beam of neutrons and to identify and quantify secondary particle emissions (e.g. photons) and relate these emissions back to number of atoms present of a given element. These systems perform optimally when their designers and operators are aware of the physical limitations inherent in these devices. For example, minimum detection limits are strongly constrained by the signal-to-noise ratio in a given system. The purpose of this paper is not to denigrate any of these systems but to discuss the strengths and limitations of various approaches. [Preview Abstract] |
Saturday, October 28, 2006 10:48AM - 11:00AM |
GB.00008: Savannah River National Laboratory Underground Counting Facility Tim Brown The SRNL UCF is capable of detecting extremely small amounts of radioactivity in samples, providing applications in forensics, environmental analyses, and nonproliferation. Past customers of the UCF have included NASA, (Long Duration Exposure Facility) the IAEA, (Iraq), and nonproliferation concerns. The SRNL UCF was designed to conduct ultra-low level gamma-ray analyses for radioisotopes at trace levels. Detection sensitivity is enhanced by background reduction, high detector efficiency, and long counting times. Backgrounds from cosmic-rays, construction materials, and radon are reduced by counting underground, active and passive shielding, (pre-WWII steel) and situation behind a Class 10,000 clean facility. High-detection efficiency is provided by a well detector for small samples and three large HPGe detectors. Sample concentration methods such as ashing or chemical separation are also used. Count times are measured in days. Recently, two SCUREF programs were completed with the University of South Carolina to further enhance UCF detection sensitivity. The first developed an ultra-low background HPGe detector and the second developed an anti-cosmic shield that further reduces the detector background. In this session, we will provide an overview status of the recent improvements made in the UCF and future directions for increasing sensitivity. [Preview Abstract] |
Saturday, October 28, 2006 11:00AM - 11:12AM |
GB.00009: Accelerate the transition of radioisotopes or unwanted weapons-grade $^{239}$Pu into stable nuclei with a system of high frequency modulation for a net energy gain Eugene Pamfiloff A process of high frequency stimulation of nucleons can be utilized for the accelerated fission, decay or controlled transition of unstable isotopes. For example $^{238}$U could be persuaded to transition promptly into $^{206}$Pb, where portions of the total mass difference of 29873.802 MeV per nucleus becomes available energy. The proposals of this paper describe an effective system for nuclei stimulation configured to accelerate such a series of 14 transitions over several milliseconds, instead of 4.47 x 10$^{9 }$years. Positive ions or ionized capsules of fuel suspended by magnetic fields and subjected to the system of correlated frequency modulation of multiple beam lines, tailored to the specific target, will emit sufficient energy to stimulate subsequent targets. The system can be applied to all radioisotopes, including $^{232}$Th, nuclear waste product isotopes such as $^{239}$Pu, and a variety of other suitable unstable or stable nuclei. Through the proposed confinement system and application of high frequency stimulation in the 10$^{22}$ to 10$^{24}$ Hz regime, the change in rest mass can be applied to both the fragmentation of subsequent, periodically injected targets, and the production of heat, making a continuous supply of energy possible. The system allows the particle fragmentation process to be brought into the laboratory and provides potential solutions to the safe disposal of fissile material. [Preview Abstract] |
Saturday, October 28, 2006 11:12AM - 11:24AM |
GB.00010: New Nuclear Decay Library for ENDF/B-VII Alejandro Sonzogni As a part of the ENDF/B-VII (Evaluated Nuclear Data File) release, a new library containing nuclear decay data was produced. Its main sources are the Evaluated Nuclear Structure Data File, which is continuously updated and the 2005 edition of the Nuclear Wallet Cards. An important component of it is the use of the Total Absorption Gamma-ray Spectrometer (TAGS) data measured by Idaho National Laboratory. The library is well suited to complex decay network calculations. It is expected to have an impact in many nuclear science and technology applications such as reactor operations and radionuclide management. Decay heat calculations and comparison with other libraries will be presented. [Preview Abstract] |
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