basic

Half-Value Layer from Linear Attenuation Coefficient Calculator

HVL = ln 2 / μ.

Compute the half-value layer (HVL) — the thickness of a shielding material that reduces a monoenergetic beam of x-rays or gamma rays by 50 %: HVL = ln 2 / μ, where μ is the linear attenuation coefficient (cm⁻¹). Also reports the TVL (tenth-value layer, ln 10 / μ) and the transmission for a given user-entered shield thickness.

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

cm⁻¹
cm

Results

Enter values and click Calculate to see results.
Was this helpful?

How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

HVL = ln 2 / μ; I/I₀ = e^(−μ·x).

In depth

Compute the half-value layer (HVL) — the thickness of a shielding material that reduces a monoenergetic beam of x-rays or gamma rays by 50 %: HVL = ln 2 / μ, where μ is the linear attenuation coefficient (cm⁻¹). Also reports the TVL (tenth-value layer, ln 10 / μ) and the transmission for a given user-entered shield thickness.