Complete info about x rays

Discovery of X-Rays

Roentgen (1974)

Discovery of X-rays:

Discovery of X-rays:
Discovered  accidentallyby  Wilhem Conard Roentgenin 1895,whilew orking with conduction of cathoderays.
Initially Nature unknown ,nameasX-rays.
FirstNobel  Prize for Physicsin

• 1901.

RoentgenpublishedfirstMedical X-ray -animage ofhis wife hand (first indication of the Medical application of x-ray).
Current estimate s  show that there are approximately 650  medicalanddental X-ray  examinationsper  1000patients per  year.

Production of X-rays


X-rays are produced when rapidly moving electrons that have been accelerated through a potential difference of order 1 kV to 1 MV strikes a metal target.

Electrons from a hot element are accelerated onto a target anode.
When the electrons are suddenly decelerated on impact, some of the kinetic energy is converted into EM energy, as X-rays.
Less than 1 % of the energy supplied is converted into X-radiation during this process. The rest is converted into the internal energy of the target.

Characteristic x-rays:


Startswithejectionofe-mainlyfromkshell(alsopossibleforL,M,…)byionization.
e-fromLorMshellfallintothevacancycreatedinthekshell.
Energydifferenceisemittedasphotons.
Asequenceofsuccessiveelectrontransitionsbetweenenergylevels.
Energyofemittedphotonsischaracteristicoftheatom




Properties of X-rays
X-rays travel in straight lines.
X-rays cannot be deflected by electric field or magnetic field.
X-rays have a high penetrating power.
Photographic film is blackened by X-rays.
Fluorescent materials glow when X-rays are directed at them.
Photoelectric emission can be produced by X-rays.
Ionization of a gas results when an X-ray beam is passed through it.



In medicine



Uses of X-rays
To diagnose illness and for treatment.
In industry
To locate cracks in metals.
X-ray crystallography
To explore the structure of materials.