335 research outputs found
Dissolution of Ordered Precipitates Due to Local Disordering and Atomic Mixing under Irradiation
Measurement by FIB on the ISS: Two Emissions of Solar Neutrons Detected?
A new type of solar neutron detector (FIB) was launched onboard the Space
Shuttle Endeavour on July 16, 2009, and it began collecting data at the
International Space Station (ISS) on August 25, 2009. This paper summarizes the
three years of observations obtained by the solar neutron detector FIB until
the end of July 2012. The solar neutron detector FIB can determine both the
energy and arrival direction of neutrons. We measured the energy spectra of
background neutrons over the SAA region and elsewhere, and found the typical
trigger rates to be 20 counts/sec and 0.22 counts/sec, respectively. It is
possible to identify solar neutrons to within a level of 0.028 counts/sec,
provided that directional information is applied. Solar neutrons were observed
in association with the M-class solar flares that occurred on March 7 (M3.7)
and June 7 (M2.5) of 2011. This marked the first time that neutrons were
observed in M-class solar flares. A possible interpretaion of the prodcution
process is provided.Comment: 36 pages, 16 figures, and 3 Tables; Advanced in Astronmy, 2012,
Special issue on Cosmic Ray Variablity:Century of Its Obseravtion
Radiation Tolerance Tests of Electronic Components for Space-borne Dust and Debris Observations
Measurement of the transverse asymmetry of -rays in the Sn(n,)Sn reaction
Largely enhanced parity-violating effects observed in compound resonances
induced by epithermal neutrons are currently attributed to the mixing of
parity-unfavored partial amplitudes in the entrance channel of the compound
states. Furthermore, it is proposed that the same mechanism that enhances the
parity-violation also enhances the breaking of time-reversal-invariance in the
compound nucleus. The entrance-channel mixing induces energy-dependent
spin-angular correlations of individual -rays emitted from the compound
nuclear state. For a detailed study of the mixing model, a -ray yield
in the reaction of Sn(n,)Sn was measured using the
pulsed beam of polarized epithermal neutrons and Ge detectors. An angular
dependence of asymmetric -ray yields for the orientation of the neutron
polarization was observed.Comment: 7 pages, 10 figure
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