A next-generation liquid xenon observatory for dark matter and neutrino physics

The nature of dark matter and properties of neutrinos are among the most pressing issues in contemporary particle physics. The dual-phase xenon time-projection chamber is the leading technology to cover the available parameter space for weakly interacting massive particles, while featuring extensive sensitivity to many alternative dark matter candidates. These detectors can also study neutrinos through neutrinoless double-beta decay and through a variety of astrophysical sources. A next-generation xenon-based detector will therefore be a true multi-purpose observatory to significantly advance particle physics, nuclear physics, astrophysics, solar physics, and cosmology. This review article presents the science cases for such a detector

A Next-Generation Liquid Xenon Observatory for Dark Matter and Neutrino Physics

The nature of dark matter and properties of neutrinos are among the mostpressing issues in contemporary particle physics. The dual-phase xenontime-projection chamber is the leading technology to cover the availableparameter space for Weakly Interacting Massive Particles (WIMPs), whilefeaturing extensive sensitivity to many alternative dark matter candidates.These detectors can also study neutrinos through neutrinoless double-beta decayand through a variety of astrophysical sources. A next-generation xenon-baseddetector will therefore be a true multi-purpose observatory to significantlyadvance particle physics, nuclear physics, astrophysics, solar physics, andcosmology. This review article presents the science cases for such a detector.<br

A next-generation liquid xenon observatory for dark matter and neutrino physics

The nature of dark matter and properties of neutrinos are among the most pressing issues in contemporary particle physics. The dual-phase xenon time-projection chamber is the leading technology to cover the available parameter space for weakly interacting massive particles, while featuring extensive sensitivity to many alternative dark matter candidates. These detectors can also study neutrinos through neutrinoless double-beta decay and through a variety of astrophysical sources. A next-generation xenon-based detector will therefore be a true multi-purpose observatory to significantly advance particle physics, nuclear physics, astrophysics, solar physics, and cosmology. This review article presents the science cases for such a detector

Magnetic properties experiments and the Surface Stereo Imager calibration target onboard the Mars Phoenix 2007 Lander: Design, calibration, and science goals

The first NASA scout mission to Mars, Phoenix, launched 4 August will land in the northern part of Mars in the locality of 68 degrees N and 233 degrees E on 25 May 2008. Part of the science payload is the Magnetic Properties Experiments (MPE) that consists of two main experiments: the Improved Sweep Magnet Experiment (ISWEEP) and 10 sets of two Microscopy, Electrochemistry, and Conductivity Analyzer ( MECA) magnet substrates with embedded permanent magnets of different strength. The ISWEEP experiment is, as the name indicates, an improved version of the Sweep Magnet Experiments flown onboard the two Mars Exploration Rovers (MERs) Spirit and Opportunity. The sweep magnet is ring shaped and is designed to allow only nonmagnetic particles to enter a small circular area at the center of the surface of this structure. Results from this experiment have shown that on the MERs hardly any particles can be detected in the central area of this ring-shaped magnet. From this we have concluded that essentially all particles in the Martian atmosphere are magnetic in the sense that they are attracted to permanent magnets. In order to improve the sensitivity of the Sweep Magnet Experiment for detection of nonmagnetic or very weakly magnetic particles, the ISWEEP holds six ring-shaped magnets, somewhat larger than the sweep magnet of the MERs, and with six different background colors in the central area. The six different colors provide new possibilities for improved contrast between these background colors, i.e., any putative nonmagnetic particles should render these more easily detectable. The Surface Stereo Imager will also take advantage of the small clean areas in the ISWEEPs and use the presumably constant colors for radiometric calibration of images. The MECA magnets work as substrates in the MECA microscopy experiments; they are built to attract and hold magnetic particles from dust samples. The collected dust will then be examined by the optical microscope and the atomic force microscope in the MECA package

Indication of drier periods on Mars from the chemistry and mineralogy of atmospheric dust

The ubiquitous atmospheric dust on Mars is well mixed by periodic global dust storms, and such dust carries information about the environment in which it once formed and hence about the history of water on Mars. The Mars Exploration Rovers have permanent magnets to collect atmospheric dust for investigation by instruments on the rovers. Here we report results from M&ouml;ssbauer spectroscopy and X-ray fluorescence of dust particles captured from the martian atmosphere by the magnets. The dust on the magnets contains magnetite and olivine; this indicates a basaltic origin of the dust and shows that magnetite, not maghemite, is the mineral mainly responsible for the magnetic properties of the dust. Furthermore, the dust on the magnets contains some ferric oxides, probably including nanocrystalline phases, so some alteration or oxidation of the basaltic dust seems to have occurred. The presence of olivine indicates that liquid water did not play a dominant role in the processes that formed the atmospheric dust.Additional co-authors: Daniel S Rodionov, Paulo A de Souza, Jr, Steve W Squyres, Tom Wdowiak, Albert Yen Output Type: Lette