Recoilwyn: Radioactive Recoil
Nuclear & Particle Physics arc, page 188 of 193. Back to The Pixelated Physics Universe
Who they are
Recoilwyn is a respectful pixel portrait of Harriet Brooks, after William Notman & Son’s 1898 photograph, with two motes of light flying apart before her: a light fast one and a heavy slow one.
Recoilwyn is a character of the Nuclear & Particle Physics arc: drawn in pixels, ruled by one piece of real physics, and never allowed to break it.
The physics
Harriet Brooks (1876–1933) was Ernest Rutherford’s first graduate student at McGill. She helped show that radium’s “emanation” was a new radioactive gas (radon), early evidence that one element can turn into another. Her 1904 Nature letter, “A Volatile Product from Radium”, reported active deposit turning up on the walls of the vessel, an early observation of what was later explained as alpha recoil: when a nucleus emits an alpha particle, the daughter nucleus is kicked the other way.pα = −pR ⇒ ER = (mα / mR) Eα pα, pR: momenta of the alpha particle and the recoiling daughter nucleus (kg m s⁻¹) Eα, ER: their kinetic energies (non-relativistic) (J or MeV) mα, mR: their masses (kg or u) For radium-226 (Eα ≈ 4.78 MeV) the radon-222 daughter recoils with about 4.78 × 4.0/222 ≈ 86 keV, enough to fly free of a surface and lodge in the walls.
No single equation is shown for this character; the physics above is stated in words because it is an observation or a piece of history, and we do not invent formulas.
Honest caveat: Brooks observed the effect; the recoil explanation came later (Hahn, and Russ & Makower, 1909). The discovery of radon is shared with Rutherford, Owens and Dorn.In characterSomething leapt from the radium and landed where it should not have been. I wrote down exactly what I saw. The explanation could catch up later.
Crossovers
Recoilwyn meets Sponara (Hertha Sponer and the Birge–Sponer Method). Sponara and Recoilwyn are both portraits of real physicists. Hertha Sponer read molecular energy levels from spectra; Harriet Brooks followed radioactive recoil. Different experiments, same rule: momentum and energy are conserved in every event they recorded.
Recoilwyn meets Mossbra (Mössbauer Effect). Recoilwyn studied the recoil of a nucleus after it emits. Mossbra avoids recoil entirely: the whole crystal lattice takes the kick, so the gamma ray loses almost no energy.
Recoilwyn meets Decay Dancer (Weak Nuclear Force / Beta Decay). Recoilwyn followed atoms recoiling from alpha decay. Decay Dancer's beta decay has a recoil too, and its energy spectrum was the clue that pointed to the neutrino.
Wear the lore
Concept keywords: Radioactive Recoil, Recoilwyn, Nuclear & Particle Physics, physics lore, Pixelated Physics