About 10,000 muons reach every square meter of the Earthıs surface a minute;
these charged particles are produced as by-products of primary cosmic rays
colliding with air molecules in the upper atmosphere, and they form the hard
component of secondary cosmic rays. Traveling at relativistic speeds, muons
can penetrate tens of meters into rocks and other matter before attenuating.
Most of interactions cause just minor deflections in the path of the muon.
We can use measurements of muon trajectories before and after they pass
through an object to estimate the object properties. We measure the sum
effect of multiple deflections and infer properties of the material after
collecting enough statistical information. This technique is especially
effective for detection of hidden chunks of high-Z materials, including SNM.
Soft component of secondary cosmic rays is composed of electrons and soft
muons, which can be more easily attenuated. Therefore, soft component
attenuation provides us with another information source, which can be used
for more effective radiography. Our goal is to use this information to
augment muon scattering and obtain better knowledge of objects. This may
allow us to detect not just nuclear materials, but other possible threats as
well, such as explosives. We discuss, how scattering and stopping can be
combined together within framework of image reconstruction.