Streakwin: Cosmic Ray Muon Flux
Cosmology & the Sky arc, page 157 of 193. Back to The Pixelated Physics Universe
Who they are
Streakwin has one line, and says it often: “One per cm² per minute. all on my target.”
Streakwin is a character of the Cosmology & the Sky arc: drawn in pixels, ruled by one piece of real physics, and never allowed to break it.
The physics
Sea-level muon flux is about 1 per cm² per minute for a horizontal detector; cosmic rays leave streaks on long CCD exposures.
$$ \begin{gathered} I \approx 1\ \text{cm}^{-2}\,\text{min}^{-1} \quad \text{(horizontal detector, sea level)} \\ I(\theta) \propto \cos^{2}\theta, \qquad I_v \approx 70\ \text{m}^{-2}\,\text{s}^{-1}\,\text{sr}^{-1} \end{gathered} $$
| Symbol | Meaning | SI unit |
|---|---|---|
| $I$ | muon flux through a horizontal detector | cm^{-2}·min^{-1} |
| $\theta$ | zenith angle | — |
| $I_v$ | vertical integral intensity (above 1 GeV/c) | m^{-2}·s^{-1}·sr^{-1} |
Sources
Crossovers
Streakwin meets Solitaren (Mean Free Path Vacuum). Solitaren's mean free path is set by how often gas molecules collide. Streakwin's muons cross the whole atmosphere and reach the ground, helped by time dilation that stretches their short lifetimes.
Streakwin meets Omegoda (Oh-My-God Particle). Streakwin's everyday muons come from cosmic rays hitting the air. Omegoda was one of the rarest of those primaries, at about 3.2 × 10²⁰ eV. What kind of particle it was is still unknown.
Wear the lore
Concept keywords: Cosmic Ray Muon Flux, Streakwin, Cosmology & the Sky, physics lore, Pixelated Physics