4 ms·

Having not read the article, nor really the Ars piece either, let me hand wave by saying that cosmic muons are produced as secondary particles emitted from a hi

Having not read the article, nor really the Ars piece either, let me hand wave by saying that cosmic muons are produced as secondary particles emitted from a high energy collision of a primary extraterrestrial particle that collides with particles in the stratosphere (around 30km up). This shower of muons is “boosted” by kinetic energy of the primary particle. That means they have a lifetime that is longer than at rest when observed from Earth, but relevant to this method, they are also temporally correlated in such a way that by determining the time of arrival at multiple stations, the origin of the primary interaction can be determined - and more importantly, the timings between the stations can be deduced. Having fixed stations, and an unfixed one, means you can infer the latter’s position through geometric analysis.

lokimedes 3y ago
To actually answer you question, it is not the same muon hitting all stations, but a spray of highly correlated muons originating from the same interaction point. Philosophically, muons are considered elementary particles, and are as such considered identical particles. Though, that has no effect in this situation.
- raattgift 3y ago
  Philosophically ... considered, what? Muons are leptons in the standard model. The ars article summarizes <https://www.cell.com/iscience/pdf/S2589-0042(23)01077-5.pdf https://www.cell.com/iscience/pdf/S2589-0042(23)01077-5.pdf>. See figure 4, which shows a photo of two scintillators (1m x 1m x 0.02m Eijen EJ-200 plastic scintillators <https://eljentechnology.com/products/plastic-scintillators/ej-200-ej-204-ej-208-ej-212 https://eljentechnology.com/products/plastic-scintillators/e...>) and a green ray representing a single muon passing through both. > it is not the same muon The green ray is not wrong because of multiple muons, but because of mutiple Coulomb scattering (MCS) within the scintillators. There is a brief overview of MCS in a muon tomography context starting at the top of the second column on the first page of <https://arxiv.org/abs/2212.04947 https://arxiv.org/abs/2212.04947>. Figures 1 and 2 therein show the trajectory of a single muon experiencing MCS within a plastic scintillator.
SiempreViernes 3y ago
Please don't read the article and instead just guess what they did. You are in fact entirely wrong: they use that the same muon passing trough two detectors, something that happens by chance, and you can identify by knowing the geometrical distance between the two detectors and convert to a very narrow time window during which you accept signals.

lokimedes 3y ago

To actually answer you question, it is not the same muon hitting all stations, but a spray of highly correlated muons originating from the same interaction point. Philosophically, muons are considered elementary particles, and are as such considered identical particles. Though, that has no effect in this situation.

raattgift 3y ago
Philosophically ... considered, what? Muons are leptons in the standard model. The ars article summarizes <https://www.cell.com/iscience/pdf/S2589-0042(23)01077-5.pdf https://www.cell.com/iscience/pdf/S2589-0042(23)01077-5.pdf>. See figure 4, which shows a photo of two scintillators (1m x 1m x 0.02m Eijen EJ-200 plastic scintillators <https://eljentechnology.com/products/plastic-scintillators/ej-200-ej-204-ej-208-ej-212 https://eljentechnology.com/products/plastic-scintillators/e...>) and a green ray representing a single muon passing through both. > it is not the same muon The green ray is not wrong because of multiple muons, but because of mutiple Coulomb scattering (MCS) within the scintillators. There is a brief overview of MCS in a muon tomography context starting at the top of the second column on the first page of <https://arxiv.org/abs/2212.04947 https://arxiv.org/abs/2212.04947>. Figures 1 and 2 therein show the trajectory of a single muon experiencing MCS within a plastic scintillator.

SiempreViernes 3y ago

Please don't read the article and instead just guess what they did. You are in fact entirely wrong: they use that the same muon passing trough two detectors, something that happens by chance, and you can identify by knowing the geometrical distance between the two detectors and convert to a very narrow time window during which you accept signals.