X Rays
1895 Wilhelm Roentgen: new radiation from cathode-ray tubes
this radiation had big penetration depth, very different from cathode-rays, it is invisible, observable only from their effect on substances
it can be produced when cathode-rays enter in different substances with high energy
it cannot be deviated by magnetic or electric fields (no charge)
X rays --> due to their unknown nature in 1895
X rays are electromagnetic waves, with very high frequency
important applications in medicine --> can reveal internal structures
an X ray spectrum typically consist of two parts:
- a continuous spectrum (produced by the
deceleration of the bombarding electrons)
- a set of discrete spikes (X-rays photons
emmited by the bombarded material)
energy of the X ray photons increases as the
atomic number of the bombarded element