browser-native science

When radiation hits a cell, this is what happens.

A single electron tears through water molecules. Thousands of reactive chemicals scatter, find DNA, and break it apart — all in a microsecond. For twenty years, simulating this took a supercomputer and a PhD. Now it runs in your browser tab.

⚡ Watch it now → what am I looking at?

No install. No signup. Free, forever. ~5 second load on a modern laptop.

What you'll see, frame by frame.

The viewer plays back a real simulated event in 4D — three spatial dimensions, plus time, scrubbing through a microsecond of radiation chemistry.

01 — the strike

An electron arrives.

It's been launched at 10,000 electron-volts — typical energy for medical X-rays. As it tears through water, it knocks electrons off molecules and slows down, leaving an ionization trail behind.

02 — the fallout

Water shatters.

Each ionization splits a water molecule into reactive chemicals — hydroxyl radicals (OH), solvated electrons (e⁻aq), hydrogen, hydronium. Tens of thousands per electron. They diffuse, react, recombine. This is the cloud you'll watch evolve.

03 — the damage

DNA gets hit.

Some radicals find DNA strands. Most cause a single break. A few — the bad ones — break both strands within ten base pairs of each other. That's a double-strand break, the lesion behind cell death and mutation.

Why anyone should care.

Cancer radiotherapy is dose calibration on this microsecond.

Astronaut shielding for Mars missions is dose calibration on this microsecond.

Whether your CT scan is safe is dose calibration on this microsecond.

For decades, only a handful of national-lab teams could see what you're about to see. Now anyone with a laptop can.

The honest numbers.

It runs in a browser, but it isn't a toy. Validated, head-to-head, against the gold-standard scientific simulator (Geant4-DNA, the same code radiobiology labs cite in published papers).

0.985×
How far the electron travels — same as the reference, within 1.5%.
2,714 nm vs 2,756 nm
509
Ionizations per electron — exact match to the reference simulator.
vs 509.1 expected
100.0%
Energy is conserved across all 8 reference energies — no leaks.
100 eV → 20 keV
~6 sec
To simulate 4,096 electrons on a laptop GPU.
vs hours on CPU

If you'd tweet this, here's a head start.

Three drafts, copy-and-go. Pick the voice that's closest to yours and edit freely.

Just clicked a button and watched 50,000 reactive radicals attack DNA in real time, in a browser tab. No install. webgpudna.com 🤯

— casual / awe

Geant4-DNA — the radiobiology Monte Carlo toolkit physicists run on HPC clusters — now runs in your browser via WebGPU. Validated against the 11.4.1 reference. Click "View ready demo" and watch a microsecond of radiation chemistry play. webgpudna.com

— technical

One of the more 'wait, what?' demos I've seen lately — a working DNA-damage simulator running entirely in WebGPU. The kind of thing that needed a supercomputer last decade. webgpudna.com

— recommendation

You can have all this in five seconds. Just click.

⚡ Watch it now →