Important: This page is an estimation aid for education, planning, and quick screening. Formal neutron dosimetry should use instrument calibration, spectral data, geometry, and site procedures.
This estimator uses the ICRP 103 style neutron radiation-weighting function and reports equivalent dose from organ or tissue absorbed dose. It also lets you apply occupancy and shielding factors for scenario comparisons.
Calculator Inputs
Calculated Results
Equivalent dose
0.000 mSv
Adjusted equivalent dose
0.000 mSv
Equivalent dose rate
0.000 mSv/h
Weighting factor
0.00
Energy in MeV
0.000000 MeV
Absorbed dose in Gy
0.000000 Gy
Lower bound
0.000 mSv
Upper bound
0.000 mSv
Weighting Factor Plot
The curve shows the neutron radiation-weighting factor as a function of neutron energy. The highlighted point marks your selected energy.
Formula Used
This estimate applies the neutron radiation-weighting factor to absorbed dose for an equivalent-dose style calculation:
Equivalent dose, H = D × wR
Adjusted equivalent dose = H × occupancy factor × shielding transmission factor
Equivalent dose rate = adjusted equivalent dose ÷ exposure time
For neutron energy En in MeV, the weighting factor is estimated as:
If En < 1 MeV:
wR = 2.5 + 18.2 × exp(-[ln(En)]² / 6)
If 1 MeV ≤ En ≤ 50 MeV:
wR = 5.0 + 17.0 × exp(-[ln(2 × En)]² / 6)
If En > 50 MeV:
wR = 2.5 + 3.25 × exp(-[ln(0.04 × En)]² / 6)
This is suitable for quick equivalent-dose estimation when neutron energy is known or reasonably approximated. Real workplace and shielding assessments may require fluence spectra, detector response, operational quantities such as H*(10), and regulatory procedures.
How to Use This Calculator
- Enter the absorbed dose and select the matching dose unit.
- Enter neutron energy and choose the correct energy unit.
- Set the exposure duration if you want a dose-rate result.
- Apply occupancy and shielding factors for adjusted scenario estimates.
- Add uncertainty to display a quick lower and upper range.
- Press Calculate Estimate to show the result above the form and in the results panel.
- Use the export buttons to save a CSV summary or a PDF snapshot.
Example Data Table
| Scenario | Absorbed Dose | Energy | Occupancy | Shielding | Estimated wR | Adjusted Equivalent Dose |
|---|---|---|---|---|---|---|
| Instrument check area | 0.05 mGy | 0.1 MeV | 1.00 | 1.00 | 12.90 | 0.645 mSv |
| Bench setup comparison | 0.25 mGy | 2.0 MeV | 0.75 | 0.80 | 18.85 | 2.828 mSv |
| Shielded review case | 0.80 mGy | 100 MeV | 0.60 | 0.35 | 5.37 | 0.902 mSv |
Frequently Asked Questions
1. What does this calculator estimate?
It estimates neutron equivalent dose from absorbed dose and neutron energy. It also applies optional occupancy, shielding, duration, and uncertainty inputs for quick scenario comparisons and exportable summaries.
2. Is equivalent dose the same as absorbed dose?
No. Absorbed dose measures deposited energy. Equivalent dose weights that absorbed dose by radiation type and energy, which is why neutron results can be much higher than the same absorbed photon dose.
3. Why does neutron energy matter so much?
Neutron biological effectiveness changes strongly with energy. The weighting factor rises and falls across the energy range, so two equal absorbed doses can produce different equivalent-dose estimates.
4. What is the shielding transmission factor?
It is a user-entered fraction from 0 to 1. A value of 1 means no reduction, while 0.40 means you assume only 40% of the unshielded equivalent dose reaches the location.
5. Can I use this for compliance reporting?
It is better used for screening, education, and planning. Compliance or formal dose assessment should follow site rules, calibrated instruments, neutron spectra, and applicable regulatory methods.
6. What if I only know dose rate?
Convert dose rate into a total absorbed dose for the chosen exposure duration, then enter that total here. The calculator reports an adjusted dose rate again after applying factors.
7. Does this calculator use ambient dose equivalent H*(10)?
No. This page estimates equivalent dose from absorbed dose and neutron energy. Operational quantities such as H*(10) are instrument and calibration based, and may differ from this simplified estimate.
8. Which units are supported?
For absorbed dose, the calculator accepts Gy, mGy, µGy, and rad. For energy, it accepts eV, keV, MeV, and GeV, then converts everything internally to MeV and Gy.