Anne Harrington was sworn in as Deputy Administrator for Defense Nuclear Nonproliferation for the National Nuclear Security Administration in October 2010. Previously, Ms. Harrington was the Director of the U.S. National Academy of Sciences Committee on International Security and Arms Control (CISAC) a position she held from March 2005 to October 2010.
Ms. Harrington served for 15 years in the U.S. Department of State, where she was Acting Director and Deputy Director of the Office of Proliferation Threat Reduction and a senior U.S. government expert on nonproliferation and cooperative threat reduction.
Ms. Harrington has been author or co-author on a number of papers on countering biological threats. She graduated with a bachelor’s of arts degree from St. Lawrence University, an M.A. from the University of Michigan, and an M.S. from the National Defense University National War College.
Position sensitive semiconductors are important tools for gamma-ray detection and imaging. Compton Imaging is now an established gamma ray imaging modality for energies ranging from about 200 keV to several MeV. The performance is only limited by intrinsic detector properties such as position and energy resolution and the ability to resolve individual interactions. In our effort we focus on the improvement of the position resolution of HPGe double-sided strip detectors (DSSD). Our detectors are 15 mm thick and have 38 strips on each side with a strip pitch of 2 mm resulting in a volume of about 100 cm3 that is read out by 76 individual preamplifiers. We are developing and benchmarking signal processing techniques to improve the position resolution to be significantly better than given by the voxel size. Specifically, we are developing Signal Decomposition (SD) algorithms, which are based on physic models of the charge creation and transport processes and mathematical techniques such as singular value decomposition to infer the energy and three-dimension of individual gamma-ray interactions. Using SD we were able to achieve a spatial resolution of about 0.5 mm resulting in about 800k spatial voxels. The increase in granularity significantly increases the imaging resolution and efficiency, which is the ultimate goal.
February 10th – NSSC Webinar: Overview of Research at LANL’s Space Science and Applications Group, 6:00 – 7:00 (EST)
Los Alamos National Laboratory is one of the world’s largest science and technology institutions, conducting world-class research and development on topics integral to the U.S. nuclear deterrent and other national security matters, energy challenges, space exploration, medicine and supercomputing. The Intelligence and Space Research Division’s Space Science and Application Group (ISR-1) is currently seeking graduate students and Post Doctoral fellows who would like to be part of our scientific discoveries and our mission to make the world safer. This talk will focus on some of the ongoing and future projects and opportunities within the ISR division that have contributed to those missions; including both space and ground based applications. Topics presented will include advanced simulation and modeling, nuclear nonproliferation, defense and space applications and detection research and development in addition to Earth and environmental strategic research.
Detailed Modeling of Fission
More than 75 years after the discovery of fission, much remains to be understood on more than a qualitative level. While there have been intense recent efforts to improve upon fission theory, this talk focuses on achieving the best possible phenomenological understanding of fission. For better or worse, phenomenology depends on available data, both as input for the models and, as output, as a measure of comparison. The first part of the talk reviews some of the available input and output data. We then turn to models of fission, from the Los Alamos model to more recent efforts. For many years, the state of the art for modeling fission in transport codes has involved sampling from average distributions such as those produced by the Los Alamos model. These “average” fission models have limited capabilities. Energy is not explicitly conserved and no correlations are available because all particles are emitted isotropically and independently. However, the energies, momenta and multiplicities of particles emitted during fission are correlated. Correlations are only calculable In models that produce complete fission events. Recently, several Monte Carlo codes have become vailable that employ event-by-event techniques. These methods are particularly useful because all event information is kept, making it possible to extract any desired correlation observables. Such codes, when included in broader Monte Carlo transport codes can be made broadly available to the community. Our fast event-by-event fission code FREYA (Fission Reaction Event Yield Algorithm), one such code, generates large samples of complete fission events. We go step by step through the physics in FREYA, describing the inputs and methodology. We also describe some of the other available models and compare our FREYA calculations with results from other models. Finally, we present some new results on neutron-neutron correlations.
More about Dr. Vogt
Ramona got her PhD in nuclear physics theory at the State University of New York at Stony Brook in 1989. She was a postdoc at Lawrence Livermore National Laboratory in Livermore, CA and at the Geschellschaft fur Schwerionenforschung near Darmstadt, Germany. She was then a member of the Nuclear Theory Group at Lawrence Berkeley National Laboratory before returning to Livermore in 2007. She has been an Adjunct Professor of Physics at UC Davis since 1995. She published the book “Ultrarelativistic Heavy-Ion Collisions” in 2007. Her physics interests include heavy quarks and quarkonium as well as her newer work In nuclear fission. She, along with Jorgen Randrup of LBNL, are the developers of the event-by-event fission model FREYA (Fission Reaction Event Yield Algorithm). She is a Fellow of the American Physical Society and served in the Executive Committee of the APS Topical Group on Hadronic Physics for six years. She explains nuclear fission to Girl Scouts and Boy Scouts at Nuclear Science Day at LBNL. Her hobby is running on any trail she can find.
Professor Richards presents on “Seismic Monitoring for Hundreds of Earthquakes per Day, and for the Occasional Nuclear Explosion.”
Paul Richards has taught at Columbia University since 1971, where he has conducted research on the theory of seismic wave propagation, the physics of earthquakes, the interior structure of the Earth, and the application of seismological methods to explosion and earthquake monitoring. He is a co-author of the advanced text “Quantitative Seismology” (available in Russian, Chinese, Japanese as well as English). He has been emeritus Professor of Natural Sciences since 2008, and is currently Special Research Scientist at Columbia.
He served terms as a visiting scholar at the U.S. Arms Control and Disarmament Agency in 1984 and 1993, participated in CTBT negotiations, is a Fellow of the American Academy of Arts and Sciences, and received the Seismological Society of America’s 2009 medal for outstanding contributions in seismology. See http://www.ldeo.columbia.edu/~richards/PGRc.v.long.html for a list of publications.
Dr. Mueller will be giving a talk titled “A novel method of assaying special nuclear materials using polarized photofission.”
Dr. Mueller will discuss his thesis work where he measured novel angular distributions of prompt neutrons in photofission, and how these measurements may be used to identify Special Nuclear Materials (SNM) or measure the enrichment of SNM.
Dr. Mueller began working in nuclear physics as an undergraduate at Washington University in St. Louis with Prof. Lee Sobotka on many-body theory and its connection to a dispersive optical model. After he graduated with a B.S. in Physics in 2009, he attended Duke University to take advantage of the facilities at Triangle Universities Nuclear Laboratory, and there he was named a DOE Office of Science Graduate Fellow. He received his Ph.D. in Physics from Duke in 2013 for these novel photofission measurements.