Energy Attenuation, Stopping Power and Range

Dear fluka discuss:

I want to calculate the energy attenuation of proton passing through
Havar foil and range of proton in O-18 water
,but I face problems as below.

1 continuous slowing down
I check ICRU report 49 and NIST website for stopping power.
http://physics.nist.gov/PhysRefData/Star/Text/PSTAR.html
Material: Silver
(MeV) Stopping Power (MeV cm2/g)
9.500E+00 2.388E+01
Silver: mass density: 10.49g/cm^3
mass density * stopping power = 250.5 MeV/cm
So , if the proton of initial energy 9.5MeV went through 35 micro
meter depth of silver.
Energy loss would be 240.5MeV/cm * 35*10^-6 = 0.8767 MeV
I think this neglects the fact that proton is continuous slowing down,
so the result would be overestimate.
How to get the accurate result?

2 Lack of the material I'm interested in

I could not find a material of Havar and O-18 water from website.
So ,for stopping power of proton for Havar foil and range in O-18
water I really have no idea.

Please advise me

My Best Regards

Chenyen Lee
Cyclotron
Deptment of Nuclear Medicine
Chang Gung Memorial Hospital
Linko, Taiwan.
Received on Thu May 1 11:28:59 2008