1. X-rays and their ability to
The production, properties and interaction of X- rays Dr. D. Mladenova Maxillo Facial & Radiology Div. WITS DENTAL SCHOOL

2. Properties of X-rays

3. X-Rays were discovered by Roentgen in 1895
They are part of electromagnetic spectrum and are invisible
X- rays are described as consisting of wave packets of energy. Each packet is called a photon and is equivalent to one quantum of energy.

4. Longer X-rays have less penetrating power
The energy carried by x-rays can be attenuated by matter i.e absorbed or scattered

5. An X-ray beam is made up of millions of photons of different energies
The diagnostic X-ray beam varies in its intensity and guantity
The factors affecting the intensity and/or the quantity of the beam are kV, mA, distance from the target, length of exposure, filtration r

6. Dental X-ray generating equipment
A tubehead
Positioning arm
A control panel and circuitry

7. Ideal requirements Safe and accurate
Capable of generating X-rays in the desired range
Small
Easy to manoeuvre and position
Stable
Easily folded and stored
Simple to operate
Robust

9. Production of x-rays on atomic level

10. Main features and requirements of an x-ray tube
The production of X- rays can be summarized as the following sequence of events
The filament is electrically heated and a cloud of electrons is produced around the filament
The high voltage ( potential difference) across the tube accelerates the electrons at very high speed towards the anode
The focusing device aims the electron stream at the focal spot on the target
The electrons bombard the target and are brought suddenly to rest
The energy lost by the electrons is transferred into either heat (about 99 %) or X-rays (about 1 %)
The X-rays are emitted in all directions from the target.Those emitted through the small window in the lead casting constitute the beam used for diagnostic purposes.

11. Heat producing collisions

12. X-Ray producing collision

13. Heat producing collisions

14. Interactions of X-Rays with matter

15. Scattering
Absorption
Attenuation
Ionization

16. Photo electric effect

17. Compton effect