Question

calculate the electorons recoil kinetic energy if thd energy of the incident photon is 150MeV (hint:1eV = 1.6×10^-19 =10^6eV​

Answer 1

Answer:

The Compton coefficient per

atom is given in Table A-4e for 1.5 MeV photons as 2.232 × 10-28 m

2

/atom. Express

this coefficient in m2

/electron, cm2

/g, m-1

. (Use Table 5-3 or the top of Table A-4e.)

To convert from atomic Compton coefficient to electronic Compton coefficient,

we must divide the atomic Compton coefficient by the number of electrons per

atom, Z, which, for aluminum, is 13.

29 2 -1

-1

28 2 -1

1.72 10 m electron

13 electron atom

2.232 10 m atom -

-

= ×

×

To convert to mass Compton coefficient, we must multiply the electronic

Compton coefficient by the electron density, which, according to Table A-4e, is

2.902 × 1026 electrons kg-1

. We must then convert m2 to cm

2 and kg to g with

appropriate conversion factors.

2 2 -1

29 2 -1 26 -1 3 -1 4 2 -2

4.98 10 cm g

1.72 10 m electron 2.902 10 electron kg 10 kg g 10 cm m

-

- -

= ×

× × × × ×

To convert to linear Compton coefficient, we must multiply the mass Compton

coefficient by the mass density, which is 2699 kg m-3

. We must convert cm2 back

to m2

, and g to kg as well.

-1

2 -1 -1 3 -1 4 2 -2

13.45 m

0.0498 cm g 2699 kg m 10 g kg 10 m cm