15,005 research outputs found
Traveling Wave Magnetic Particle Imaging for determining the iron-distribution in rock: Traveling Wave Magnetic Particle Imaging for determining the iron-distribution in rock
Determining the composition of solid materials is of high interest in areas such as material research or quality assurance. There are several
modalities at disposal with which various parameters of the material can be observed, but of those only magnetic resonance imaging
(MRI) or computer tomography (CT) offer anon-destructive determination of material distribution in 3D. A novel non-destructive imaging method is Magnetic Particle Imaging (MPI), which uses
dynamic magnetic fields for a direct determination of the distribution of magnetic materials in 3D. With this approach, it is possible to determine and differentiate magnetic and non-magnetic behaviour.
In this paper, the first proof-of-principle measurements of magnetic properties in solid environments are presented using a home-built traveling wave magnetic particle imaging scanner
A time lens for high resolution neutron time of flight spectrometers
We examine in analytic and numeric ways the imaging effects of temporal
neutron lenses created by traveling magnetic fields. For fields of parabolic
shape we derive the imaging equations, investigate the time-magnification, the
evolution of the phase space element, the gain factor and the effect of finite
beam size. The main aberration effects are calculated numerically. The system
is technologically feasible and should convert neutron time of flight
instruments from pinhole- to imaging configuration in time, thus enhancing
intensity and/or time resolution. New fields of application for high resolution
spectrometry may be opened.Comment: 8 pages, 11 figure
The Coronal Analysis of SHocks and Waves (CASHeW) Framework
Coronal Bright Fronts (CBF) are large-scale wavelike disturbances in the
solar corona, related to solar eruptions. They are observed in extreme
ultraviolet (EUV) light as transient bright fronts of finite width, propagating
away from the eruption source. Recent studies of individual solar eruptive
events have used EUV observations of CBFs and metric radio type II burst
observations to show the intimate connection between low coronal waves and
coronal mass ejection (CME)-driven shocks. EUV imaging with the Atmospheric
Imaging Assembly(AIA) instrument on the Solar Dynamics Observatory (SDO) has
proven particularly useful for detecting CBFs, which, combined with radio and
in situ observations, holds great promise for early CME-driven shock
characterization capability. This characterization can further be automated,
and related to models of particle acceleration to produce estimates of particle
fluxes in the corona and in the near Earth environment early in events. We
present a framework for the Coronal Analysis of SHocks and Waves (CASHeW). It
combines analysis of NASA Heliophysics System Observatory data products and
relevant data-driven models, into an automated system for the characterization
of off-limb coronal waves and shocks and the evaluation of their capability to
accelerate solar energetic particles (SEPs). The system utilizes EUV
observations and models written in the Interactive Data Language (IDL). In
addition, it leverages analysis tools from the SolarSoft package of libraries,
as well as third party libraries. We have tested the CASHeW framework on a
representative list of coronal bright front events. Here we present its
features, as well as initial results. With this framework, we hope to
contribute to the overall understanding of coronal shock waves, their
importance for energetic particle acceleration, as well as to the better
ability to forecast SEP events fluxes.Comment: Accepted for publication in the Journal of Space Weather and Space
Climate (SWSC
Is there a resting frame in the universe? A proposed experimental test based on a precise measurement of particle mass
According to the Special Theory of Relativity, there should be no resting
frame in our universe. Such an assumption, however, could be in conflict with
the Standard Model of cosmology today, which regards the vacuum not as an empty
space. Thus, there is a strong need to experimentally test whether there is a
resting frame in our universe or not. We propose that this can be done by
precisely measuring the masses of two charged particles moving in opposite
directions. If all inertial frames are equivalent, there should be no
detectable mass difference between these two particles. If there is a resting
frame in the universe, one will observe a mass difference that is dependent on
the orientation of the laboratory frame. The detailed experimental setup is
discussed in this paper.Comment: 9 pages, 4 figure
- …