The image above depicts the solar wind traveling from the sun and meeting the Earth's magnetosphere. In this solar wind there are many charged particles. Most of these particles have been stripped of their electrons and carry on as independent nuclei. The neutrons in these nuclei play a large part in neutron detection, which is one of the tools used in predicting space weather.
Neutron detection is a way of predicting space weather by counting the number of
high-energy particles that come into contact with the Earth. This process
is performed using a neutron monitor. A neutron monitor is a device that uses a combination
of polyethylene, an energy absorbing plastic, slabs and boron counters to detect high-energy
particles passing through Earth.
The neutron monitor records the amount of cosmic rays that strike a specified area
over a period of time. Space weather is the amount of cosmic rays being sent by the sun. Therefore, by measuring
the number of cosmic particles hitting the Earth, we can find patterns in space weather.
These patterns can be used to predict future trends, as well as the effects that events
that are observed on the sun will have on Earth. The data recorded by the neutron monitor shows cycles such as a
Forbush decrease. The data also helps predict the result of new solar flares, based on
previous measurements.
What is neutron detection?
How does the neutron monitor work?
The neutron monitor is made of three main parts, each part contains six cosmic ray counters,
which are tubes filled with boron gas, covered by lead casing and polythene slabs.
The sun emits solar corpuscular radiation; solar corpuscular radiation is comprised of particles.
These particles are considered primary particles as long as they travel uninhibited. If one of these
particles contacts an atom in the atmosphere, but continues to travel towards Earth, it is considered
a secondary particle. These particles travel from the sun, through the atmosphere, and finally through the
building that houses the instruments before they can be counted by the instruments. Once the particles reach the detector,
they enter the polyethylene slabs. There, a combination of polyethylene and lead absorb enough of the particles'
energy so that a boron atom in one of the counters can absorb the neutrons from one of the particles.
When the particles contact the gas, the boron atoms to split into ions, which strip electrons from atoms in the tube,
producing a charge in the tube of gas. Each charge that is detected is recorded as one count.
How do we predict space weather using the neutron monitor?