137
Cs
NUCLIDE CARD
Cs-137
- Half-life
- 30.05 y
- Radiation clue
- γ · 661.7 keV
- Common context
- Calibration and environmental monitoring
Professional nuclear data toolkit
Nuclides keeps radiation work precise, fast, and reliable.
A comprehensive reference and calculation companion for nuclear technology, radiological medicine, radiation monitoring, and research. Built for daily field work, education, and deep analysis.
What it does
Everyday nuclear workflows, one interface.
Authoritative datasets + practical calculators for radiation work, education, and fast decision-making.
Try it in your browser
Turn nuclear data into something you can explore.
Four lightweight tools inspired by the Nuclides app. All calculations stay in this 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
Convert activity units instantly.
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.
Curated learning cards only. Open the Nuclides app for the complete data library.
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
Designed for clarity in high-stakes environments.
Built for
Specialists who cannot afford guesswork.
Nuclides supports radiation workers, nuclear engineers, educators, and students across the full spectrum of nuclear science.
Radiological operations
- Radiation monitoring and protection teams
- Nuclear power plant operations and planning
- Emergency response and INES reference
- Source classification and safety compliance
Research & education
- Radiological medicine and imaging labs
- Nuclear engineering coursework
- Decay chain analysis and nuclide evolution
- Unit conversions across SI and Imperial systems
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.
Ready to deploy Nuclides in your workflow?
Request access or learn more about institutional rollout.