I need to calculate de thickness of a sheet of Zinc that is being bombarded by deuterium nuclei. I'm given that the fraction of nuclei dispersed below $\theta=90ยบ$ with $T=8MeV$ is $0.9999$ and the density of the sheet $\rho=7.14 g/cm^3$.
From this pdf (page 7)
(http://www.personal.soton.ac.uk/ab1u06/teaching/phys3002/course/02_rutherford.pdf)
I found a relation with a few approximations that could give me the thickness of the sheet. I found that:
$$L=\Bigg(\frac{16\pi \epsilon_0 T }{Z_1 Z_2}\Bigg)^2\frac{M_{Zn}\Delta n \sin^4(\theta/2) }{\rho }$$
where I called $M_{Zn}$ the atomic mass of Zinc and $\Delta n$ the fraction of atoms meassured. The problem is that with this equation I get an $L$ of about $10^{-20}m$ which is odd to say the least.
The most probable thing is that I'm not undersanding the relations shown in the article right.