14,794 research outputs found
Neutron methods for the direct determination of the magnetic induction in thick films
We review different neutron methods which allow extracting directly the value
of the magnetic induction in thick films: Larmor precession, Zeeman spatial
beam-splitting and neutron spin resonance. Resulting parameters obtained by the
neutron methods and standard magnetometry technique are presented and compared.
The possibilities and specificities of the neutron methods are discussed
Polarized neutron channeling as a tool for the investigations of weakly magnetic thin films
We present and apply a new method to measure directly weak magnetization in
thin films. The polarization of a neutron beam channeling through a thin film
structure is measured after exiting the structure edge as a microbeam. We have
applied the method to a tri-layer thin film structure acting as a planar
waveguide for polarized neutrons. The middle guiding layer is a rare earth
based ferrimagnetic material TbCo5 with a low magnetization of about 20 mT. We
demonstrate that the channeling method is more sensitive than the specular
neutron reflection method
A polarised infrared flare from Sagittarius A* and the signatures of orbiting plasma hotspots
In this article we summarise and discuss the infrared, radio, and X-ray
emission from the supermassive black hole in the Galactic Centre, SgrA*. We
include new results from near-infrared polarimetric imaging observations
obtained on May 31st, 2006. In that night, a strong flare in Ks band (2.08
microns) reaching top fluxes of ~16 mJy could be observed. This flare was
highly polarised (up to ~40%) and showed clear sub-structure on a time scale of
15 minutes, including a swing in the polarisation angle of about 70 degrees.
For the first time we were able to observe both polarised flux and short-time
variability, with high significance in the same flare event. This result adds
decisive information to the puzzle of the SgrA* activity. The observed
polarisation angle during the flare peak is the same as observed in two events
in 2004 and 2005. Our observations strongly support the dynamical emission
model of a decaying plasma hotspot orbiting SgrA* on a relativistic orbit. The
observed polarisation parameters and their variability with time might allow to
constrain the orientation of accretion disc and spin axis with respect to the
Galaxy.Comment: 9 pages, 8 figures, accepted for publication in MNRA
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