GRASP-X: Gamma-Ray Attenuation & Shielding Parameters

For an element, enter its symbol (e.g., H for hydrogen), for a compound, use its chemical formula (e.g., H2O for water).
For a mixture, enter the chemical composition in the form;

70H2O + 20NaCl + 10HCl for mole

0.45H2O + 0.4NaCl + 0.15HCl for mass fractions. (Coefficients of the compounds should add up 1 for mass fractions.)

Choose the type: Mole Mass

Choose the photon energy range (optional):
Enter density:

Check the parameters to be plotted:

Mass Attenuation Coefficient
Half-Value Layer (HVL)
Tenth-Value Layer (TVL)
Mean Free Path (MFP)
Atomic Cross Section (σ_a)
Electronic Cross Section(σ_e)
Effective Atomic Number (Z_Eff)
Effective Electron Density (N_Eff)

Last Update: Dec 20, 2025.

• Revised MAC interpolation approach: exponential fitting replaced by power-law (log–log) interpolation to better reflect XCOM data trends.

Photon Energy (MeV)	Mass Attenuation Coefficient (cm²/g)	Half-Value Layer (HVL)	Tenth-Value Layer (TVL)	Mean Free Path (MFP)	Atomic Cross Section (σ_a)	Electronic Cross Section (σ_e)	Effective Atomic Number (Z_Eff)	Effective Electron Density (N_Eff)