The thickness of radiation shielding materials to reduce radiation energy to half of its initial value, that called half-value thickness (HVL, also called half value layer). It can be used as an effective method to estimate appropriate radiation shielding thickness. It is more convenient to estimating radiation shielding effectiveness according the thickness of radiation shielding material using half-value thickness method. The radiation intensity will be reduced to 1/2n of its initial value trough n times half-value thickness of radiation shielding material.
The calculation of tungsten half-value thickness:
A,Z--the atomic weight and atomic number of tungsten;
Δ1/2Al-- The half-value thickness of aluminum shielding；
Δ1/2W--The half-value thickness of tungsten shielding
During design of tungsten polymer radiation shielding is calculated according to requirements of shield to abate the multiple shielding materials' thickness.
Formula：K = e0.693 d / Δ1/2
K：shield weakened multiple
Δ1/2:The shielding material of the half-value layer values
d：Shielding thickness, with the half-value layer thickness of their units, you need to half-value layer thickness of the quality of translation into the thickness of the material, divided by the density of the material can be obtained.