How to use the pair production threshold calculator
Find the energy a gamma photon needs to create an electron and positron pair, and the energy left over. Enter photon energy in the field above; the threshold for pair production, kinetic energy shared by pair are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “pair production threshold”, “gamma ray creates electron positron”, “1.022 MeV”, “calculate pair production threshold”, “find threshold for pair production”.
Formula
Variables
- E — Photon energy (MeV)
Worked example
With photon energy = 3 MeV, the calculator gives threshold for pair production ≈ 1.021998 MeV; kinetic energy shared by pair ≈ 1.978002 MeV.
Frequently asked questions
What is the pair production threshold calculator used for?
Find the energy a gamma photon needs to create an electron and positron pair, and the energy left over. It helps with questions such as “pair production threshold”, “gamma ray creates electron positron”, “1.022 MeV”.
What is the formula for the pair production threshold calculation?
Threshold for pair production (MeV) = 2 × ME × CLIGHT × CLIGHT / QE / 1e6. Kinetic energy shared by pair (MeV) = E-[Threshold for pair production]. Here E is photon energy (MeV).
What inputs do I need for the pair production threshold calculator?
You need photon energy in MeV. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the pair production threshold calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the pair production threshold result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.