Estimate neutron dose equivalents from absorbed dose inputs. Apply energy weighting automatically or manually. Export results to CSV and PDF instantly.
| # | Absorbed Dose | Energy | wR (approx.) | Equivalent Dose H |
|---|---|---|---|---|
| 1 | 0.25 mGy | 0.5 MeV | ~18.1 | ~4.53 mSv |
| 2 | 0.10 mGy | 2 MeV | ~17.4 | ~1.74 mSv |
| 3 | 5 µGy | 14 MeV | ~10.5 | ~52.5 µSv |
| 4 | 0.02 mGy | 60 MeV | ~2.8 | ~56 µSv |
| 5 | 1 rad | 1 MeV | ~20.0 | ~0.20 Sv |
Equivalent dose is estimated from absorbed dose using:
H = D × wR
where D is absorbed dose (Gy) and wR is the neutron radiation weighting factor (dimensionless).
For neutrons, an energy-dependent weighting factor can be used (energy in MeV):
wR = 2.5 + 18.2·exp(−(ln En)²/6) for En < 1
wR = 5.0 + 17.0·exp(−(ln(2En))²/6) for 1 ≤ En ≤ 50
wR = 2.5 + 3.25·exp(−(ln(0.04En))²/6) for En > 50
Optional effective dose contribution for a selected tissue:
E = H × wT
Neutrons carry no electric charge, so they penetrate materials differently than photons or electrons. When neutrons interact with tissue, they produce secondary charged particles that can concentrate energy deposition. For protection work, absorbed dose (Gy) is converted to an equivalent dose (Sv) using a neutron weighting factor.
Absorbed dose measures energy per mass in gray, where 1 Gy equals 1 joule per kilogram. Practical measurements often use mGy or µGy. Equivalent dose uses sievert because it includes radiation quality. In this calculator, 1 rad is converted to 0.01 Gy, and results are reported in Sv, mSv, and µSv.
Neutron biological effectiveness changes with energy. Thermal neutrons are around 0.025 eV, while reactor and accelerator fields can span keV to tens of MeV. The automatic option applies an energy-based function that peaks near the MeV region, where weighting can approach about 20, then decreases at higher energies.
The workflow is: convert the absorbed dose to Gy, convert neutron energy to MeV, compute or accept a weighting factor, then calculate H = D × wR. For example, 0.10 mGy at roughly 2 MeV with wR near 17.4 gives an equivalent dose near 1.74 mSv. This mirrors the example table for quick validation.
Equivalent dose applies to a tissue or organ. If you select a tissue weighting factor (wT), the tool reports an effective dose contribution E = H × wT. This is useful for comparing relative impacts across tissues when multiple organs are involved, while still treating results as an estimate.
If you enter an exposure duration, the calculator also reports an equivalent dose rate. For instance, 1.74 mSv received over 10 minutes corresponds to about 10.4 mSv per hour. Rates help compare scenarios such as short maintenance tasks versus longer stays near neutron sources.
Real neutron environments are often mixed-energy, scattered by shielding, and accompanied by gamma radiation. Geometry, moderation, and spectrum shape can change the effective weighting. A single “representative” energy is a simplification, so use the manual wR option when you have site-specific guidance or instrument-reported factors.
Use these outputs for education, preliminary planning, and consistency checks. For compliance, rely on calibrated dosimetry, workplace monitoring, and applicable regulations. If results seem high, stop and consult a qualified radiation protection professional before taking further action.
Use the absorbed dose in tissue or a suitable proxy from your measurement method. Choose the correct unit (Gy, mGy, µGy, nGy, or rad) so the calculator can convert consistently.
Use automatic weighting when you have a single representative neutron energy and want an energy-based estimate of wR. It is convenient for quick checks across common energy ranges.
Manual wR is better when you already have an approved weighting factor from site procedures, instrumentation, or a spectrum-based assessment. It avoids forcing a single energy assumption.
Selecting wT multiplies the equivalent dose to show an effective dose contribution for that tissue. It is a simplified indicator for comparison, not a full-body effective dose calculation.
Neutron interactions produce different secondary particles at different energies, affecting biological effectiveness. The weighting factor can be higher around the MeV region and lower at very high energies.
For mixed spectra, a single energy is only an approximation. If you have spectrum data, compute a weighted average externally or use a provided site factor, then enter it as manual wR.
Yes. Exports include the displayed fields so you can document inputs, conversions, and the final equivalent dose estimate. Always keep your original measurement context alongside exported files.
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.