Gamma Spectroscopy: Measuring Atomic Numbers?

[indigojoker]

Is there a way to measure the atomic number of a source using gamma spectroscopy? Like, I know that if you have different back scattering material, it will produced different intensity backscattering peaks, but is there a formula that relates intensity of backscattered peaks to the atomic number?

 

[malawi_glenn]

gamma spectroscopy measures the energy of the emitted photons when a metastable state deexcites. Rutherford backscattering, you not use gamma rays..

 

[indigojoker]

umm back scattering from compton effect. gamma rays hit electron and if the scattering angle is 180 degree, then the scattered gamma ray will leave energy in the detector forming the backscattering peak while the scattered electron will form the compton edge.

so my question is asking if there is a way to measure the atomic number of the radioactive source using different backscattering materials (such as lead and aluminum) and measuring the difference in backscattering peak?

 

[indigojoker]

hmm still no ideas?

 

[malawi_glenn]

there are better ways to measure Z of material, then using backscattered gammas (compton edge). Rutherford Backscattering is the method which is used in industry nowadays. See for example Krane: Introductory nuclear physics, p 796 and forward.

 

[indigojoker]

this is for a lab. i am still confused to HOW someone can measure the Z of material using backscattered gamma rays? could you explain?

 

[malawi_glenn]

There are formulas where the compton edge is given as a function of atomic number of the material and incoming energy of the photon.

 

[indigojoker]

i have never seen the compton edge be related to the atomic number. it would be great if i can be directed to this formula because I've been looking for it and can't find it

 

[malawi_glenn]

Not me neither, but if your lab assistants wants you to find such a relation, it should exist. If not, then maybe you have missunderstood the lab-info.

 

[indigojoker]

by "find such a relation" they mean go on the internet and look. there is no way i can "derive" such an equation from the experiments, i was just wondering if they were online at all

 

[malawi_glenn]

internet? Why not textbooks in libraries etc?

 

[indigojoker]

"i have never seen the compton edge be related to the atomic number. it would be great if i can be directed to this formula because I've been looking for it and can't find it"

 

[malawi_glenn]

What sources have you considered? Google?

Why not texbooks about experimental nuclear physics / introductory books in Nuclear physics - chapters on experiment.

 

[indigojoker]

i tried all of that. i have six nuclear/experimental physics books from the library and when they talk about gamma ray spectroscopy, it doesn't mention anything about compton edge and atomic number. I've read all the internet sources on it, i don't think one exists...