Decay Simulator: Thorium-207
General data
| Element name | Thorium |
|---|---|
| Chemical symbol | Th |
| Atomic number Z | 90 |
| Isotope name (symbol) | Thorium-207 (Th-207) |
| Neutron number N | 117 |
| Mass number A=Z+N | 207 |
Interactive radioactive decay simulation of Thorium-207: atom-by-atom decay, full decay chain, charts of nuclei count and activity.
| Half-life | 10 ms |
|---|
Radioactive decay series
- Thorium-207 10 ms
- Radium-203 31 ms
- Radon-199 0.60 s
- Polonium-195 4.64 s
- Lead-191 1.33 min · 94.0%
- Bismuth-195 183 s · 6.0%
- Thallium-191 unknown · 94.0%
- Lead-195 ≈ 15 min · 6.0%
- Thallium-195 1.15 h · 6.0%
- Mercury-195 10.68 h · 6.0%
- Gold-195 186.01 d · 6.0%
- Platinum-195 stable · 6.0%
- Mercury-187 1.9 min · 0.048%
- Gold-187 8.3 min · 0.048%
- Platinum-187 2.35 h · 0.048%
- Iridium-187 10.5 h · 0.048%
- Osmium-187 stable · 0.048%
How to read the simulation
Grid: each pixel is one atom of the starting isotope. When an atom decays, the pixel takes the colour of the decay product - in decay series mode the product can decay further. The moment each atom decays is random, but the probability follows from the half-life, so after one T½ about half of the atoms remain, after two - about a quarter.
Chart N(t): what percentage of the sample atoms each nuclide makes up at a given moment. The line of the starting isotope falls (by half after each T½), the lines of stable products rise, and those of short-lived ones first rise, then fall.
Chart A(t): activity, i.e. the number of decays per second (becquerel, Bq). It depends on the number of atoms and on how fast they decay: for the same number of atoms, the shorter the T½, the higher the activity.
Simulation time runs faster (or slower) than real time - the time scale slider sets the multiplier. This way you can watch the decay of isotopes that live from fractions of a second to billions of years.
Well-known isotopes
- H-3 - Tritium - glowing watch hands, nuclear fusion fuel.
- C-14 - Radiocarbon dating.
- K-40 - Natural radioactivity - in bananas and in our bodies.
- Co-60 - Radiotherapy and radiation sterilization.
- I-131 - Thyroid treatment; Chernobyl fallout.
- Cs-137 - Long-lasting contamination after Chernobyl and Fukushima.
- Rn-222 - Radon in basements and mines.
- Ra-226 - The longest-lived isotope of radium - the element discovered by Marie and Pierre Curie in 1898.
- U-235 - Nuclear power plant fuel; start of the actinium series.
- U-238 - Age of the Earth; start of the uranium series.
- Pu-238 - Power source for space probes (Voyager, Curiosity rover).
- Am-241 - Ionization smoke detectors.
Data sources
- NNDC Wallet Cards 2023 - Data as of 15 October 2024 - licence: Public domain