# How can I find the nuclear interaction length in solid lead given atomic number, radius of the lead nucleus and lead density?

I need to estimate the nuclear interaction length in solid lead given the atomic mass unit $$A=207.2u$$, radius of lead nucleus $$R=r_0A^{1/3}$$ where $$r_0=1.25fm$$ and the density of lead is $$\rho=11.34g/cm^2$$. I've been trying to find calculations for the nuclear interaction length but all I can find are tables with the length already given but no method of calculation.

For example the Particle Data Group has a page for lead, and while I don't expect them to have details of the calculations, this is one of the only places I can find the nuclear interaction length and no other sites mention how it is calculated.

How do I calculate the nuclear interaction length given this information?