Proton Elastic and Inelastic Scattering at Intermediate Energies from Isotopes of Oxygen and 9-Be as Part of a Unified Study of These Nuclei

This work was supported by National Science Foundation Grants PHY 76-84033A01, PHY 78-22774, and Indiana Universit

Forging strategic partnerships with industry: The Industrial Fellows Program

Science, technology, and industrial policy are at an important nexus due to long developing trends in the national and international economy and recent events in national security affairs. The research and development assets built by the American taxpayer in response to the Cold War face a quest for relevance in the new era. National competitiveness in international markets has emerged as an important new priority. To better understand the perspective of US industry the management of the Los Alamos National Laboratory has initiated an Industrial Fellows Program which has placed six individuals at US corporations. Their goal is to create strategic partnerships through increased understanding of technical needs of industry and the technical capabilities of the Laboratory

Proton Elastic and Inelastic Scattering at Intermediate Energies from Isotopes of Oxygen and 9-Be as Part of a Unified Study of these Nuclei

This work was supported by the National Science Foundation Grants NSF PHY 78-22774 A03, NSF PHY 81-14339, and by Indiana Universit

Proton Elastic and Inelastic Scattering at Intermediate Energies from Isotopes of Oxygen and 9-Be as Part of a Unified Study of These Nuclei

This work was supported by the National Science Foundation Grant NSF PHY 78-22774 A02 & A03 and by Indiana Universit

A Dissipative-Particle-Dynamics Model for Simulating Dynamics of Charged Colloid

A mesoscopic colloid model is developed in which a spherical colloid is represented by many interacting sites on its surface. The hydrodynamic interactions with thermal fluctuations are taken accounts in full using Dissipative Particle Dynamics, and the electrostatic interactions are simulated using Particle-Particle-Particle Mesh method. This new model is applied to investigate the electrophoretic mobility of a charged colloid under an external electric field, and the influence of salt concentration and colloid charge are systematically studied. The simulation results show good agreement with predictions from the electrokinetic theory.Comment: 17 pages, 8 figures, submitted to the proceedings of High Performance Computing in Science & Engineering '1

Proton Elastic and Inelastic Scattering at Intermediate Energies from Isotopes of Oxygen and 9-Be as Part of a Unified Study of These Nuclei

Supported by the National Science Foundation and Indiana Universit

Self-help interventions for anxiety disorders: An overview.

Anxiety disorders are highly prevalent and are associated with a marked impairment in quality of life and a huge economic cost to society. Unfortunately, a considerable number of people who struggle with anxiety do not seek or receive adequate treatment. Self-help interventions have been proposed to constitute a relatively cheap, effective, efficient, and low-threshold intervention for anxiety disorders. This paper offers a critical discussion of their advantages and disadvantages and the evidence for their effectiveness. We conclude that guided self-help can play a major role in mental health care for patients with anxiety disorders. However, several research questions need to be answered before broad-scale dissemination is possible. The Internet will continue to play a prominent role in the further development of this field of research and clinical practice

Physics with low temperature antiprotons

The advent of the new beam cooling techniques and their application to antiproton production has already made possible major advances in high energy physics. These same techniques offer uniquely exciting possibilities for ultralow energy physics. Through a combination of deceleration stages, antiprotons produced at several GeV (where the production cross section is at a maximum) can be made available for experiments at thermal velocities. High precision measurements of the antiproton mass and magnetic moment can be performed. Comparison of these measurements with those for the proton will test the CPT invariance of internal baryon dynamics at an unprecedented level. In addition the gravitational constant for antimatter can be measured for the first time, and to high accuracy. Each of these measurements will provide very important information on the dynamical symmetry between matter and antimatter in our universe. Antiprotons at thermal velocities will also make these fundamental particles available for experiments in condensed matter and atomic physics. The recent speculation that antiprotons may form metastable states in some forms of normal matter could open many new avenues of basic and applied research

Antiprotons are another matter

Theories of gravity abound, whereas experiments in gravity are few in number. An important experiment in gravity that has not been performed is the measurement of the gravitational acceleration of antimatter. Although there have been attempts to infer these properties from those of normal matter, none of these theoretical arguments are compelling. Modern theories of gravity that attempt to unify gravity with the other forces of nature predict that in principle antimatter can fall differently than normal matter in the Earth's field. Some of these supergravity theories predict that antimatter will fall faster, and that normal matter will fall with a small Baryon-number dependance in the earth's field. All of these predictions violate the Weak Equivalence Principle, a cornerstone of General Relativity, but are consistent with CPT conservation. In our approved experiment at LEAR (PS-200) we will test the Weak Equivalence Principle for antimatter by measuring the gravitational acceleration of the antiproton. Through a series of deceleration stages, antiprotons from LEAR will be lowered in energy to approx.4 Kelvin at which energy the gravitational effect will be measureable. The measurement will employ the time-of-flight technique wherein the antiprotons are released vertically in a drift tube. The spectrum of time-of-flight measurements can be used to extract the gravitational acceleration experienced by the particles. The system will be calibrated using H/sup -/ ions which simulates the electromagnetic behavior of the antiproton, yet is a baryon to approx.0.1%. To extract the gravitational acceleration of the antiproton relative to the H/sup -/ ion with a statistical precision of 1% will require the release of approx.10/sup 6/ to 10/sup 7/ particles

Excitation of lasing media using antiproton-annihilation products

Lasing has been achieved in many different media using a wide variety of excitation mechanisms including low-energy electron or proton beams and recoiling fission products. In all cases, the power density produced in the medium has been the critical parameter. Recent calculations indicate that a region of high-power density can be achieved in high-density lasing media by allowing antiprotons to annihilate in the material with an intense magnetic field present. Because of the long range of energetic annihilation products, the media can be gaseous, liquid, or solid. The thermalization time is the critical parameter for this excitation mechanism which for liquid-density media, such as Ar-Xe mixtures, is about 2.1 ns. Based on these calculations power density of about 100 MW/cm/sup 2/ can be achieved using a level of antiprotons that is currently available today. Development of an antiproton pumping source may allow fundamental reaction kinetics in a wide variety of lasing systems to be performed in a university environment. The results of the calculations in a liquid medium and at different magnetic field strength will be presented. In addition, the design of an ongoing experiment using an 800 MeV proton beam to pump a liquid density excimer cavity will be discussed. These preliminary experiments intend to focus on fundamental kinetics and on the effects of a strong magnetic field on reactions. 13 refs., 7 figs