Abstract
A new type of solar neutron detector (FIB) was launched on board the Space Shuttle Endeavour on July 16, 2009, and 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 South Atlantic Anomaly (SAA) region and elsewhere and found the typical trigger rates to be 20 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 possibly 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 had been observed in M-class solar flares. A possible interpretation of the production process is provided.
Highlights
A Brief History of Solar Neutron DetectionHigh-energy protons coming from the Sun on February 28 and March 3, 1942 were first discovered by Forbush and published in 1946 [1]
Neutron monitors or solar neutron telescopes observed no solar neutrons from August 2009 to the end of July 2012, which may suggest that the soft X-ray flux measured by the GOES satellite does not necessarily correspond to the intensity of solar neutrons from the Sun. The link between this fact and the magnetic field structure [67] remains unclear, it remains a fascinating subject to be studied. Another surprising fact is for such medium-class solar flares as those that occurred on March 7 (M3.7) and June 7, 2011 (M2.5), the LAT detector on board the Fermi satellite had observed long-lasting gamma-ray emissions
A new solar neutron detector was launched on July 16, 2009, on board the Space Shuttle Endeavour, and began operation at the International Space Station (ISS) on August 25, 2009
Summary
High-energy protons coming from the Sun on February 28 and March 3, 1942 were first discovered by Forbush and published in 1946 [1]. The subsequent scope of remarkable events from solar cycle 22 may include the detections of high-energy gamma rays and neutrons in association with the six extremely powerful solar flares with X12 observed during June 1 and 15, 1991. The question of whether the long-lasting high-energy gammaray emission is attributable to the continuous acceleration of the protons above 300 MeV [29], or the injection of flare accelerated particles into a large coronal loop with release at the mirror points of the loop where the gamma rays are produced, is very interesting [38, 39], the final answer to which will hopefully be obtained in solar cycle 24.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
