Understand the physical quantity
What is Radiation Time, Distance and Shielding Scenario?
Radiation measurement distinguishes activity, detected count rate, concentration, attenuation, absorbed dose, and equivalent dose. A conversion or screening relationship must preserve which physical quantity was actually entered.
Reconcile the common time-distance-shielding arithmetic in one transparent screening scenario while keeping absorbed and equivalent dose quantities separate.
The relationship
Keep quantity and basis explicit
Point-source unshielded rate scales as reference rate × (reference distance/scenario distance)². Shielding factor is 2^(−HVL count) or entered transmission; accumulated dose = scenario rate × hours × occupancy factor. Reverse modes solve one bounded variable.
See the workflow
What the calculator is doing
1Entered physical quantity2Apply decay, detector, or geometry model3Reported activity, count, or dose quantity
Worked context
Read the output in context
A reference 100 µSv/h at 1 m becomes 25 µSv/h at 2 m; one entered HVL gives 12.5 µSv/h, and 0.5 h at 100% occupancy gives 6.25 µSv.
Interpret with care
Important boundary
This is a screening model only. It assumes a point source, unchanged field geometry and energy, an applicable entered dose-rate quantity, and a valid shielding factor. It excludes source extent, buildup, scatter, leakage, occupancy patterns, regulatory limits, medical decisions, risk, and shielding or work approval.
The result does not provide a safety limit, medical interpretation, personal-risk estimate, shielding approval, release decision, treatment plan, or regulatory authorization.
Browse Light & radiation for related physical quantities.
Quick guide
How to use this calculator
- Choose the physical radiation quantity and solve direction before entering measurements. Keep activity, count rate, absorbed dose, equivalent dose, time, distance, material attenuation, and detector efficiency separate.
- Enter isotope, detector, geometry, material, or field data only from an applicable measurement or authoritative record; these pages do not supply generic safety values or hidden presets.
- Use companion outputs to reconcile the arithmetic, then retain every stated boundary. A screening result is not authorization for exposure, handling, shielding, release, transport, treatment, or disposal.
Calculation method
How the radiation time, distance and shielding scenario calculator works
Reconcile the common time-distance-shielding arithmetic in one transparent screening scenario while keeping absorbed and equivalent dose quantities separate.
Point-source unshielded rate scales as reference rate × (reference distance/scenario distance)². Shielding factor is 2^(−HVL count) or entered transmission; accumulated dose = scenario rate × hours × occupancy factor. Reverse modes solve one bounded variable.
Worked example
Radiation Time, Distance and Shielding Scenario example
A reference 100 µSv/h at 1 m becomes 25 µSv/h at 2 m; one entered HVL gives 12.5 µSv/h, and 0.5 h at 100% occupancy gives 6.25 µSv.
Point-source unshielded rate scales as reference rate × (reference distance/scenario distance)². Shielding factor is 2^(−HVL count) or entered transmission; accumulated dose = scenario rate × hours × occupancy factor. Reverse modes solve one bounded variable.
Supported inputs
Precision and limits
Radiation boundary
This is a screening model only. It assumes a point source, unchanged field geometry and energy, an applicable entered dose-rate quantity, and a valid shielding factor. It excludes source extent, buildup, scatter, leakage, occupancy patterns, regulatory limits, medical decisions, risk, and shielding or work approval.
Units and precision
Calculations normalize compatible units once, retain working precision, and round only for display. Very small and large nonzero values use scientific notation; displayed precision cannot exceed the entered measurements or source data.
Decision boundary
This calculator does not provide a dose limit, regulatory threshold, medical interpretation, personal-risk estimate, radiation-protection program, or professional approval. Use applicable instruments, current authoritative data, and qualified radiation-protection expertise for consequential decisions.
Privacy
Entered values and results stay in this browser and are not sent to analytics or third parties.
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