Check source activity
Move between Bq and Ci before comparing source labels, laboratory notes or reference values.
Convert activity →For radiation work, research & learning
Nuclear data and radiation calculators, in your pocket.
Look up half-lives and emission energies, calculate radioactive decay, and convert activity units. Keep a nuclear science reference at hand in the lab, at your desk, or while studying.
Free browser tools · No account needed. App pricing and advanced features are listed in each store.
Find your starting point
What are you working on?
Understand a half-life
See the fraction remaining as time passes, then use the app for broader nuclide data and decay calculations.
Explore decay →Learn common nuclides
Search isotope half-lives, decay modes and natural abundance, then open a decay calculation.
Browse nuclides →What it does
From an isotope lookup to your next calculation.
Explore the app by task: find nuclear data, work through decay calculations, or consult radiation and material references.
Try it in your browser
Start with a quick answer. No install needed.
Convert Bq and Ci, explore half-lives, or browse eight common nuclides. These browser tools are free to use without an account; calculation inputs stay in your browser.
RADIOACTIVE DECAY
How much remains after each half-life?
Choose a nuclide, then move through time to see exponential decay.
Cs-137
Half-life: 30.05 years
Remaining activity
50.0%
Relative activity follows A/A₀ = (1/2)ⁿ.
ACTIVITY UNITS
Bq to Ci converter — and back.
Move between becquerel and curie units without leaving the page.
Reference relation: 1 Ci = 3.7 × 10¹⁰ Bq.
Converted values
GAMMA SPECTRUM
Match the peak to a nuclide.
Read the simplified spectrum and choose the most likely answer.
1 / 3
661.7 keV
Which nuclide best matches this peak pattern?
Choose an answer to reveal the clue.
Educational visualization only; real spectra also depend on detector response and background.
QUICK REFERENCE
Find a nuclide by symbol or application.
Search a curated set of familiar nuclides and open a compact reference card.
137
Cs
NUCLIDE CARD
Cs-137
- Half-life
- 30.05 y
- Radiation clue
- γ · 661.7 keV
- Common context
- Calibration and environmental monitoring
Curated learning cards only. Open the Nuclides app for the complete data library.
Why get the app?
Go beyond the browser examples.
A broader nuclear data library
Move beyond the eight web learning cards to nuclide data, decay chains, radiation energies and emission probabilities.
Connected reference tools
Bring element properties, nuclide references, decay calculations and unit conversions together in one app.
Reference data you can carry
Bundled reference data is available offline. Online resources and some advanced features require connectivity or additional access.
Professional workflow studio
Move from reference data to practical intuition.
Three browser-based sandboxes reveal how Nuclides connects nuclear data, radiation protection, nuclear medicine, and material references.
DISTANCE + SHIELDING
See how geometry and shielding reshape a field.
γ
Relative field index
100%
Illustrative lead HVL
6.5 mm
Geometry
1 / r²
Relative teaching model only—not a survey, dose assessment, or shielding design.
NUCLEAR MEDICINE CLOCK
Follow calibrated activity through real clock time.
T½ = 1.83 h
Physical decay only; no biological clearance is included.
Remaining activity
173.4 MBq
Educational preview only. Clinical work requires approved procedures and qualified professionals.
MATERIAL REFERENCE
Turn a density reference into a quick mass estimate.
Pb
Estimated mass
1.134 kg
Reference density
11.34 g/cm³
Compared with water
11.34×
Typical reference values; composition, temperature, and manufacturing conditions can change density.
Inside the app
Explore the connected Nuclides toolkit.
01
DATA FOUNDATION
From element to emission line.
Search elements and nuclides, open decay data, and move directly into calculations.
Screenshots
See the app before you download.
Built for
A reference for the questions you meet every day.
Use Nuclides alongside your established procedures, whether you work with radiation sources, study nuclear science, or teach the next cohort.
In the lab & in the field
- Look up a nuclide’s half-life and radiation emissions
- Convert source activity between Bq, MBq, Ci and mCi
- Review decay over a chosen time interval
- Consult radiation protection and source references
At your desk & in the classroom
- Explore nuclides used in PET and SPECT
- Connect emission energies with decay data
- Explain exponential decay with interactive examples
- Look up element properties and nuclear facilities
Reference suite
Physical constants, material densities, and conversions.
Keep critical numbers at hand: densities of common materials, radiation constants, and unit conversions for activity, dose, pressure, length, area, and flow.
Optional in-app purchases are available to unlock advanced features.
Before you download
A few practical questions.
Can I use Nuclides without installing the app?
Yes. The activity converter, decay explorer, peak challenge and eight nuclide learning cards on this page are free browser tools. They are a limited preview of the app.
What does the app add?
A broader nuclide library, connected references and calculators, and bundled offline data. Some advanced features use in-app purchases; check your platform’s store listing for current details.
Can I use the web examples for clinical or safety decisions?
The interactive examples support learning and reference. They do not replace a validated measurement method, a clinical protocol or a shielding assessment.
Keep Nuclides ready for your next question.
Download for iOS or Android to explore the connected data library and calculators. See the store listing for pricing, supported devices and in-app purchases.
Free browser tools · No account needed. App pricing and advanced features are listed in each store.