| Home > Back to School > Physics |
|
Physics
|
|
|
X-rays are produced in two ways.
|
Bremsstrahlung X-Rays
- Radiation which is emitted when accelerated electrons are decelerated when they are fired at a metal target Original German term for "braking radiation".
-
Characterized by a continuous distribution of radiation.
- Becomes more intense and shifts toward higher frequencies when the energy of the
bombarding electrons is increased.
|
|
|
Characteristic x-rays
- Emitted from heavy elements when their electrons make transitions from higher to
lower atomic energy levels.
- X-rays produced by transitions from the n=2 to n=1 levels are called K-alpha
x-rays, and those for the n=3->1 transiton are called K-beta x-rays.
- Have sharply defined frequencies associated with the difference between the
atomic energy levels of the target atoms. Frequencies of the characteristic
x-rays can be predicted from the Bohr model.
|
|
|
Moseley Plot
- Frequencies of the characteristic x-rays from a large fraction of the elements of the periodic table.
- A straight line obtained when the square root of the frequencies of the characteristic x-rays from the elements is plotted against the atomic number
|