In a scattering experiment, an aluminium foil of thickness L = 10E-6 m is placed in a beam of intensity of 6E12 particles per second. The differential scattering crosss section is known to be of the form.(adsbygoogle = window.adsbygoogle || []).push({});

[tex]\frac{d\sigma}{d\Omega} = A + Bcos^2 (\theta) [/tex]

where [tex]\theta [/tex] is the scattering angle and [tex]\Omega [/tex] the solid angle.

With a detector area of 0.1x0.1 m^2, placed at a distance of 5m from the foil, it is found that the mean counting rate is 40 Hz when [itex]\theta [/itex] is 30 degrees and 31.5Hz when [itex]\theta [/itex] is 60 degrees. Find the values of A and B.

Clearly I had to set up two simulataneous equations using the different [itex]\theta [/itex] values.

I've found the number of targets which is just

[tex] \frac{N_{A}L\rho}{A}[/tex]

where A is the mass number (27 for Aluminium).

I looked on wiki and the differential cross section is

[tex]\frac{d\sigma}{d\Omega} = \frac{scattered flux / unit of solid angle

}{initial flux / unit of surface}[/tex] but I don't really understand how to relate this to the information I have (I guess the incident flux is just the number of targets x multiplied by the beam intensity per unit area)

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Hard nuclear physics cross section problem

**Physics Forums | Science Articles, Homework Help, Discussion**