Cosmic Muon Images

What is a muon?

A muon is a fundamental particle which means that it doesn't have any internal structure. You can take the largest magnifying glass you can find and the muon has nothing more for you to see. One can imagine the muon as a "fat" electron that is to say an electron with much heavier mass but not stable like an electron. This means that if you find a muon in your house you can be sure that it will not be there when you come back, most likely it won't be there after you blink. It decays very fast, in 2.2μs after it is created, this is 0.0000022 seconds and people's blink lasts around 100 - 150 ms or 0.001 seconds. So the phrase "blink and you missed it" fits perfectly here. A free neutron in contrast will decay after 15 minutes so plenty of blinks there. A muon decays into an electron and two other interesting particles called neutrinos (a story for another time).

Why do you need my help instead of using machines?

Human brain is by evolution a pattern recognition machine. Except from the general bias of a human brain towards the recognition of patterns relating to self preservation each "human machine" has its own biases as well. Someone may see an elephant in the clouds when another can see a truck. This is also true with the perception of real things for instance where someone sees a snake someone else sees a garden hose. We believe that in our case this competing biases will cancel themselves out and provide by consensus a result much more accurate than any other program or machine we would be able to currently develop.

Our project would indeed benefit by the use of a machine if the machine was looking for something specific. It is difficult for computers to follow a heuristic approach in problem solving and it would take a huge amount of effort to do this properly, not to mention resources that are very scarce in research nowadays. Even if we were capable of creating this human replacing machine, at some point we would need people to check the results by eye to see if what the machine provides makes sense.

Instead of this we decided to use the results you will provide to afterwards train a machine to recreate them.

What if I do the task wrong?

Don't worry about that. If you think that what you recognize is right then that's enough. Of course
we can provide you with some guidance as to the procedure you have to follow and this is what we try to do through the tutorial but what the result of following this guidelines will be is entirely up to you. There is no right or wrong. In the end every event will be subjected to the consensus of the majority but like in democracy that doesn't mean that the minority was on the wrong.

What is the impact of my work on science?

Muon tomography is an imaging technique and this means that it is used to create images of the interior of massive objects. The most important thing for these images is how crisp they are which translates into how accurately we can determine the density differences between neighboring regions inside the object.

Our goal with Cosmic Muon Images project is to make better the accuracy of our method with respect to the particle identification. We want to understand what particles correspond to what patterns. This will help us develop our detector simulation and the machine learning algorithms we need to identify particles and types of events.

The degree to which this goal is achieved will affect the setup design of our experiments in a multitude of ways depending on the nature of the findings. We may be able to better determine the time we will need for the acquisition of data, the placement of the detector with respect to the target of even come up with new designs for our detectors.

These efforts will provide more accurate results and will affect many applications of muon tomography mainly in Geology and Geophysics. In our webinar Marina discusses the study of Volcano Domes and the hydrologic pathways that lie beneath using muon tomography and other Geophysical techniques and she gives an outlook on the different conclusions one can reach in this domain of science.

We also spent the last couple of years in studying the potential of discovering buried monuments with muon tomography. It is very helpful for archaeologists to know exactly where to dig and what they should expect to find in terms of chambers and structures. This can help with better planning the excavation and be better prepared while removing artifacts so that they don't remain exposed for a long period to the elements of the weather. Another recent breakthrough that proved the impact of such imaging techniques in archaeology was the discovery of a voided segment (see figure) in Khufu's Pyramid that could prove to be a previously unknown chamber for the Archaeologists to investigate.

Other fields that are affected is mining and other underground activities where knowing the overburden is important. In our webinar Antoine explains the difficulties behind the excavation of the new Metro line in Paris and how determining the overburden helps civil engineers plan better and avoid stalling their progress due to tunnel collapses.

These are some examples where the application of muon tomography can provide insights and help evolve scientific knowledge and these are also the domains that you could affect positively through your contribution in Cosmic Muon Images.