26 research outputs found
X-rays Studies of the Solar System
X-ray observatories contribute fundamental advances in Solar System studies
by probing Sun-object interactions, developing planet and satellite surface
composition maps, probing global magnetospheric dynamics, and tracking
astrochemical reactions. Despite these crucial results, the technological
limitations of current X-ray instruments hinder the overall scope and impact
for broader scientific application of X-ray observations both now and in the
coming decade. Implementation of modern advances in X-ray optics will provide
improvements in effective area, spatial resolution, and spectral resolution for
future instruments. These improvements will usher in a truly transformative era
of Solar System science through the study of X-ray emission.Comment: White paper submitted to Astro2020, the Astronomy and Astrophysics
Decadal Surve
Perspectives on Astrophysics Based on Atomic, Molecular, and Optical (AMO) Techniques
About two generations ago, a large part of AMO science was dominated by
experimental high energy collision studies and perturbative theoretical
methods. Since then, AMO science has undergone a transition and is now
dominated by quantum, ultracold, and ultrafast studies. But in the process, the
field has passed over the complexity that lies between these two extremes. Most
of the Universe resides in this intermediate region. We put forward that the
next frontier for AMO science is to explore the AMO complexity that describes
most of the Cosmos.Comment: White paper submission to the Decadal Assessment and Outlook Report
on Atomic, Molecular, and Optical (AMO) Science (AMO 2020
X-rays Studies of the Solar System
X-ray observatories advance Solar System studies by probing Sun-object interactions, developing surface composition maps, probing magnetospheric dynamics, and tracking astrochemical reactions. Implementing modern X-ray optics in future instruments will foster a truly transformative era of Solar System science through the study of X-ray emission
Perspectives on Astrophysics Based on Atomic, Molecular, and Optical (AMO) Techniques
About two generations ago, a large part of AMO science was dominated by experimental high energy collision studies and perturbative theoretical methods. Since then, AMO science has undergone a transition and is now dominated by quantum, ultracold, and ultrafast studies. But in the process, the field has passed over the complexity that lies between these two extremes. Most of the Universe resides in this intermediate region. We put forward that the next frontier for AMO science is to explore the AMO complexity that describes most of the Cosmos
Ionization and Positonium Formation in Noble Gases
Absolute measurements are presented for the positron-impact cross sections for direct ionization and positronium formation of noble gas atoms in the range of energies from threshold to 90 eV. The experiment uses a cold, trap-based positron beam and the technique of studying positron scattering in a strong magnetic field. The current data show generally good, quantitative agreement with previous measurements taken using a qualitatively different method. However, significant differences in the cross sections for both direct ionization and positronium formation are also observed. An analysis is presented that yields another, independent measurement of the direct ionization and positronium formation cross sections that is in agreement with the present, direct measurements to within ±10% for argon, krypton, and xenon. Comparison with available theoretical predictions yields good quantitative agreement for direct ionization cross sections, and qualitative agreement in the case of positronium formation
Differential cross sections for positron-xenon elastic scattering
Absolute measurements of differential cross sections for the elastic scattering of positrons from xenon are made at 2, 5 and 8 eV using a trap-based beam and the technique of measuring scattering cross sections in a strong magnetic field. Calculations are carried out using the relativistic Dirac equations with a static plus polarization potential. Generally good absolute agreement is found between experiment and theory
Positron Scattering and annihilation Studies Using a Trap-Based Beam
An overview is presented of recent studies of the interaction of low-energy positrons with atoms and molecules using a trap-based positron beam. The beam is tunable from ∼100 meV to many electron volts, with a typical energy resolution of 25 meV (FWHM)