Compton Scattering Calculator

What Is Compton Scattering?

Compton scattering is the inelastic collision of a photon with a nearly free electron. The photon loses energy and its wavelength increases. Arthur Compton explained this in 1923, supporting the particle nature of light.

Compton Scattering Formulas

$$\Delta\lambda = \lambda_c (1 - \cos\theta)$$ $$\lambda_c = \frac{h}{m_e c} \approx 2.43 \text{ pm}$$

Scattered wavelength:

$$\lambda' = \lambda + \Delta\lambda$$

At θ = 90°, $\Delta\lambda = \lambda_c \approx 2.43$ pm. At θ = 180° (backscatter), $\Delta\lambda = 2\lambda_c \approx 4.86$ pm—the maximum shift for a given incident energy.

Frequently Asked Questions

What is the Compton wavelength of the electron?

λ_c = h/(m_e c) ≈ 2.43 pm. It sets the scale of wavelength shift and does not depend on the incident photon energy.

Why does wavelength increase after scattering?

Energy and momentum conservation require the photon to transfer energy to the recoiling electron. Lower photon energy means longer wavelength.

What scattering angle gives the largest shift?

180° backscatter gives Δλ = 2λ_c, the maximum possible shift for any incident wavelength.

Can I enter photon energy instead of wavelength?

Yes. The calculator converts E = hc/λ to find the incident wavelength, then applies the Compton formula.

When is Compton scattering important?

It dominates X-ray and gamma-ray interactions with low-Z materials. Medical imaging, radiation shielding, and astrophysics all rely on Compton physics.

Report

What Is Compton Scattering?

Compton Scattering Formulas

Frequently Asked Questions

Related Tools

Recent Visits