Analyze distance, intensity, exposure, and shielding assumptions. Get fast results with practical formulas and exports. Built for students, technicians, researchers, and daily safety estimations.
| Distance (m) | Relative Intensity | Example Reading (mSv/h) | Reduction from 1 m |
|---|---|---|---|
| 1 | 1.0000 | 800.0000 | 0.0000% |
| 2 | 0.2500 | 200.0000 | 75.0000% |
| 3 | 0.1111 | 88.8889 | 88.8889% |
| 4 | 0.0625 | 50.0000 | 93.7500% |
| 5 | 0.0400 | 32.0000 | 96.0000% |
Primary equation: I = k / d²
Ratio equation: I₂ = I₁ × (d₁² / d₂²)
Distance equation: d₂ = d₁ × √(I₁ / I₂)
In these formulas, I is radiation intensity, k is the source constant, and d is distance from the source. The calculator uses these relationships to estimate intensity changes, required distance, source constant, and relative exposure ratio.
Inverse square law of radiation explains how intensity changes with distance from a point source. It is a core rule in physics, dosimetry, and field safety. When distance doubles, intensity falls to one quarter. When distance triples, intensity falls to one ninth. This simple pattern helps users estimate exposure quickly.
Radiation intensity does not decrease in a straight line. It spreads over a larger area as distance grows. That geometric spread causes a rapid drop in measured strength. The calculator helps students, technicians, and researchers test this effect without manual algebra.
This method is useful in X ray work, gamma surveys, detector setup, and controlled laboratory practice. It also supports planning for shielding placement and safer working positions. Better distance estimates reduce unnecessary exposure and improve measurement consistency.
The main relationship is I = k / d². Here, I is intensity, k is source strength, and d is distance from the source. If one reading is already known, the ratio form is often easier. That form is I₂ = I₁ × (d₁² / d₂²). The calculator uses both expressions.
The distance solver is useful when you know a reference reading and need a target exposure limit. The source constant solver is helpful when building a model from measured data. The ratio tool quickly shows intensity change, exposure reduction, and percent drop.
Always keep units consistent. A reference distance in meters should stay in meters unless converted first. The same rule applies to centimeters and feet. The intensity unit can be counts per second, mSv/h, or any other consistent unit.
Real environments may also include shielding, scattering, detector limits, and source geometry effects. Those factors can change readings. Even so, the inverse square model remains a first estimate. It is fast, transparent, and easy to audit. Use this calculator for learning, validation, and radiation planning.
Instead of repeating manual steps, users can compare distance cases. That saves planning time and reduces arithmetic mistakes. Clear results, exports, and examples also support review, reporting, and discussion. It also helps verify homework, field notes, and detector setup assumptions before measurements begin.
It means radiation intensity falls in proportion to the square of distance. If distance doubles, intensity becomes one quarter. If distance triples, intensity becomes one ninth.
It works best for point-like sources in open space. It is a strong estimate when shielding, scattering, and complex source geometry are limited.
Yes. You can use mSv/h, µSv/h, counts per second, or another unit. The key requirement is consistency across all entered intensity values.
Distance enters the formula as a squared value. Mixed units can produce wrong ratios and wrong intensity predictions. Use one distance unit for the full calculation.
Yes. Shielding can lower real intensity beyond the inverse square estimate. This calculator focuses on distance effects only, so shielding should be considered separately.
Yes. Use the required distance mode. Enter a known reference reading, the reference distance, and a target intensity limit to estimate a safer distance.
Because intensity changes with distance squared. Even a modest step back can significantly reduce exposure, especially when working close to a strong source.
No. It is useful for planning, education, and quick estimates. Formal compliance work should also use calibrated instruments, procedures, and applicable safety regulations.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.