Physics division annual report 2005.

Glover, J. ; Physics

关键词: ASTROPHYSICS;    BETA DECAY;    FLAME PROPAGATION;    LIGHT NUCLEI;    NEUTRON-RICH ISOTOPES;    NUCLEAR PHYSICS;    NUCLEAR STRUCT;   

DOI  :  10.2172/925338
RP-ID  :  ANL-06/53
PID  :  OSTI ID: 925338
Others  :  TRN: US0803042

美国|英语

来源: SciTech Connect

【 摘 要 】

This report highlights the research performed in 2005 in the Physics Division of Argonne National Laboratory. The Division's programs include operation of ATLAS as a national user facility, nuclear structure and reaction research, nuclear theory, medium energy nuclear research and accelerator research and development. The mission of Nuclear Physics is to understand the origin, evolution and structure of baryonic matter in the universe--the matter that makes up stars, planets and human life itself. The Division's research focuses on innovative new ways to address this mission and 2005 was a year of great progress. One of the most exciting developments is the initiation of the Californium Rare Ion Breeder Upgrade, CARIBU. By combining a Cf-252 fission source, the gas catcher technology developed for rare isotope beams, a high-resolution isobar separator, and charge breeding ECR technology, CARIBU will make hundreds of new neutron-rich isotope beams available for research. The cover illustration shows the anticipated intensities of low-energy beams that become available for low-energy experiments and for injection into ATLAS for reacceleration. CARIBU will be completed in early 2009 and provide us with considerable experience in many of the technologies developed for a future high intensity exotic beam facility. Notable results in research at ATLAS include a measurement of the isomeric states in {sup 252}No that helps pin down the single particle structure expected for superheavy elements, and a new low-background measurement of {sup 16}N beta-decay to determine the {sup 12}C({alpha},{gamma}){sup 16}O reaction rate that is so important in astrophysical environments. Precise mass measurements shed new light on the unitarity of the quark weak-mixing matrix in the search for physics beyond the standard model. ATLAS operated for 4686 hours of research in FY2005 while achieving 95% efficiency of beam delivery for experiments. In Medium-Energy Physics, radium isotopes were trapped in an atom trap for the first time, a major milestone in an innovative search for the violation of time-reversal symmetry. New results from HERMES establish that strange quarks carry little of the spin of the proton and precise results have been obtained at JLAB on the changes in quark distributions in light nuclei. New theoretical results reveal that the nature of the surfaces of strange quark stars. Green's function Monte Carlo techniques have been extended to scattering problems and show great promise for the accurate calculation, from first principles, of important astrophysical reactions. Flame propagation in type 1A supernova has been simulated, a numerical process that requires considering length scales that vary by factors of eight to twelve orders of magnitude. Argonne continues to lead in the development and exploitation of the new technical concepts that will truly make an advanced exotic beam facility, in the words of NSAC, 'the world-leading facility for research in nuclear structure and nuclear astrophysics'. Our science and our technology continue to point the way to this major advance. It is a tremendously exciting time in science for these new capabilities hold the keys to unlocking important secrets of nature. The great progress that has been made in meeting the exciting intellectual challenges of modern nuclear physics reflects the talents and dedication of the Physics Division staff and the visitors, guests and students who bring so much to the research.