Compton Scattering

[Bobster]

Any ideas how to do this question ?

In a Compton type experiment X-rays scattered through 90 degrees suffered one percent reduction in energy.What was the incident energy of the X-rays ? You can assume that the electron coiled non-relativistically.

Any help would be really appreciated ! :smile:

Bob

[Bobster]

Oh by the way,i used the equation :


dL=h/mc (1-cos angle)

and i got dL=2.43 E -12

Since the energy reduction is 1 % i did

hc/L-hc/L' =0.01

and L'=L+2.43 E -12

so we end up with a quadratic :

L^2 - (2.43 E -12)L-(4.83 E -35)=0

Solving I got, L= O or -2.43 E -12

Hence incident energy is hc/0 or hc/-2.43 E -12

=> energy =infinity :surprised or hc/(-2.43 E -12). :confused:

Now is this total rubbish,or am I getting somewhere ? :bugeye:

Cheers for any help !
Bob

[BLaH!]

I believe you made an error when calculating the final energy (and hence wavelength) of the X-ray. Do it like this. The final energy of the X-ray E_f = 0.99E_i where the i stands for "initial". Now use the Einstein relation for the energy of a photon: E = \frac{hc}{\lambda} to figure out the relationship between the final and initial wavelengths of the X-rays. You shouldn't get any type of quadratic term in \lambda

[Bobster]

Thanks mate ! that was exactly my mistake.I cant believe I made that error :cry: but oh well !. :rolleyes:

Cheers again !

This world needs more people like :approve: you

[Andrew Mason]

Any ideas how to do this question ?

In a Compton type experiment X-rays scattered through 90 degrees suffered one percent reduction in energy.What was the incident energy of the X-rays ? You can assume that the electron coiled non-relativistically.

Any help would be really appreciated ! :smile:

Bob
I think the key is to get the recoil angle of the electron. It is almost 45 degrees (tan\theta = .99). Plug that into the Compton formula and you will get the magnitude of the wavelength change. That change represents a loss of one percent of the original energy.

AM