Spectrally resolved scattering of ultrafast K-α x-rays has provided experimental validation of the modeling of the compression and heating of shocked matter. The elastic scattering component has ...characterized the evolution and coalescence of two shocks launched by a nanosecond laser pulse into lithium hydride with an unprecedented temporal resolution of 10 picoseconds. At shock coalescence, we observed rapid heating to temperatures of 25,000 kelvin when the scattering spectra show the collective plasmon oscillations that indicate the transition to the dense metallic plasma state. The plasmon frequency determines the material compression, which is found to be a factor of 3, thereby reaching conditions in the laboratory relevant for studying the physics of planetary formation.
This book is intended to be used as a textbook and research reference for the field of nuclear nonproliferation. The book is primarily technical and focussed on methods of detecting clandestine ...nuclear material that might be illicitly transported. The book also touches on nuclear forensics, i.e. methods for identification, attribution, and establishment of transport pathways for illicit nuclear material. Also covered are topics of methods used for arms control and treaty verification, and an assessment of technologies under development for all of the above. A description of the government and international agencies involved in nuclear terrorism prevention, nuclear safeguards, and arms control is also included.
Ice Flow Direction Change in Interior West Antarctica Siegert, Martin J.; Welch, Brian; Morse, David ...
Science (American Association for the Advancement of Science),
09/2004, Letnik:
305, Številka:
5692
Journal Article
Recenzirano
Upstream of Byrd Station (West Antarctica), ice-penetrating radar data reveal a distinctive fold structure within the ice, in which isochronous layers are unusually deep. The fold has an axis more ...than 50 kilometers long, which is aligned up to 45° to the ice flow direction. Although explanations for the fold's formation under the present flow are problematic, it can be explained if flow was parallel to the fold axis ~1500 years ago. This flow change may be associated with ice stream alterations nearer the margin. If this is true, central West Antarctica may respond to future alterations more than previously thought.
Nuclear Forensics Morse, Edward C
Analytical Methods for Nonproliferation,
01/2016
Book Chapter
The two types of nuclear forensics, pre-detonation and post-detonation, are differentiated, and the types of information to be gathered are identified. Methods to provide attribution are explored, ...including isotope chronometers on the actinide decays, oxygen, lead, and strontium isotope identification, material characteristics such as morphology and structure, and in the case of nuclear reactor fuel, the dimensions of the pellets. Plutonium is discussed from the standpoint of gallium alloying and from the microstructure, revealing heat treatments being used. Next, there is a discussion about the tools used in nuclear forensic analysis, including alpha, beta, and gamma spectroscopy, neutron counting, and various types of mass spectrometry.
The Nuclear Fuel Cycle Morse, Edward C
Analytical Methods for Nonproliferation,
01/2016
Book Chapter
Vast amounts Nuclear fuel cycle ore are mined to produce usable stocks of uranium due to the low concentration of uranium in the ores. The worldwide distribution of uranium ore is discussed. Next, ...the steps in preparing this material for processing in enrichment plants are described. Enrichment technologies, including gaseous diffusion, centrifuges, electromagnetic separation, and laser isotope separation, are described. The concept of the Separative Work Unit, or SWU, is introduced, and the mass balance calculations for an enrichment cascade are given. The proliferation potential for each of these schemes is described. Reactors are used to make plutonium, and the features making reactor types attractive or unattractive for weapon-grade plutonium production are described. Conversion of military material to civilian use is discussed, and proliferation risks in the waste stream are assessed.
Nuclear Testing Morse, Edward C
Analytical Methods for Nonproliferation,
01/2016
Book Chapter
The early history Nuclear testing above-ground nuclear testing is discussed, along with the formation of treaties to limit and later to ban nuclear testing. The structure of the Comprehensive Test ...Ban Treaty Organization (CTBTO) is outlined, along with its International Monitoring System (IMS). The physics and technology of each type of nuclear test monitoring is discussed, starting with the general nature of fission product distributions and the relationship with the isotope undergoing fission and the neutron energies involved. The fission product signatures for xenon, cesium, krypton, and argon are discussed, their atmospheric transport is studied, and the three technologies used at IMS radioxenon stations are explored. Next seismic waves are discussed, along with some historical examples of nuclear detection with seismic signals. Hydroacoustic signals are also discussed, and finally infrasound signals in the atmosphere.
Signatures and Background Morse, Edward C
Analytical Methods for Nonproliferation,
01/2016
Book Chapter
Models for radiation transport in simple geometries are developed, with an emphasis on self-shielding and distributed sources. Three mechanisms for gamma ray attenuation—photoelectric, Compton, and ...pair production, are described. Some end-to-end calculations are shown for the estimated count rates with realistic sources and detectors. The impact of background radiation in potentially masking a source from detection is explored. Radiation background sources in the ground and air are described, with particular emphasis on the uranium and thorium decay chains, with tables of the characteristic gamma-ray lines given. Cosmogenic radiation is also explored, along with neutron backgrounds. Next, the impact of naturally occuring radioactive material (NORM) and technologically enhanced NORM (TENORM) are discussed.
The structure of international, national, and non-governmental agencies that participate in the worldwide activity to control nuclear proliferation is discussed here. The International Atomic Energy ...Agency (IAEA) is described from the standpoints of its organization, reporting functions, the treaties behind its functions, and the technical support that it provides. Its role in safeguards and verification, upholding the standards of the Additional Protocol, and promoting peaceful uses of nuclear energy are detailed. Next, the organizations within the US government involved in nuclear proliferation are discussed: these include the Departments of Homeland Security, Energy, State, and Justice. The US Intelligence Community, with its seventeen individual branches is discussed. The nonproliferation-relevant activities in the US Nuclear Regulatory Commission are also outlined. Next the role of non-governmental organizations (NGOs) is discussed. Their activities include promoting international peace and security, publicizing nuclear construction and service activities, and providing guidance and advocacy on export control issues related to nuclear proliferation.
Active Interrogation Morse, Edward C
Analytical Methods for Nonproliferation,
01/2016
Book Chapter
Active interrogation is defined and general properties of active interrogation systems are described for various applications. Active interrogation with fast neutron sources are detailed, including ...differential die-away analysis, delayed neutrons from fission, and delayed gammas from fission. Next a treatment of neutron transport for fast neutrons is given, along with concepts from age theory and methods to treat hydrogenous media. Next photofission active interrogation is explored. Then nuclear resonance fluorescence (NRF) is studied from the nuclear physics involved, and from potential practical implementations. Photon sources for NRF are studied, including bremsstrahlung, laser Compton upshift, and laser wakefield acceleration combined with Compton upshift. Lastly, the health physics aspects applicable to these systems are presented, with some examples of radiation dose calculations for neutron-based and photon-based systems.
Nuclear Explosives Morse, Edward C
Analytical Methods for Nonproliferation,
01/2016
Book Chapter
The history of the development of the first nuclear devices in the US are discussed from the standpoint of both the science and the politics behind this decision to move towards developing such ...devices. The Hiroshima and Nagasaki weapons were developed through completely different processes–one with uranium and one with plutonium. The different paths are compared and contrasted. The basic physics of nuclear weapons is discussed from the vantage point of the now-declassified Los Alamos Primer. The development of fusion-boosted weapons is also described, along with the historical backdrop of the Cold War and the arms race in the 1960s and beyond. The impact of the dismemberment of the Soviet Union on the availability of weapons-usable nuclear material is outlined, and the classification of nuclear material is described from the viewpoint of various national and international regulatory bodies.
