1 / 8

Third lecture

Third lecture. Interactions of radiation with matter. (1)-Interaction of  with matter:- i-T he  particle follows a straight, short path in the material it penetrates. ii-It causes very dense ionization & excitation events along the track.

kay
Télécharger la présentation

Third lecture

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Third lecture

  2. Interactions of radiation with matter (1)-Interaction of  with matter:- i-The  particle follows a straight, short path in the material it penetrates. ii-It causes very dense ionization & excitation events along the track. iii-the most  ranges are less than 5-6 cm in air.

  3. Interactions of radiation with matter (2)-Interaction of  with matter:- i-The  particle scatters frequently, causing what is often described as a drunken man’s path. ii-the range of  is considerably greater than an . iii-ionization & excitation events along the path are much less than that due to 

  4. Interactions of radiation with matter (3)-Interaction of  with matter:- • It depends on the photon energy & the atomic number of the material. • Photon can be absorbed by photoelectric effect; it can be scattered by Compton scattering; and it can be converted to particles of mass by pair production.

  5. (3)-Interaction of  with matter:- • photoelectric effect: • The incoming photon is absorbed to a k orbital electron. • Then the electron is ejected from the atom. • This electron causes further ionization. • X-ray is often emitted when the vacancy is filled.

  6. (3)-Interaction of  with matter:- Compton scattering: • Is scattering of  or x-ray by an outermost electron in an atom. • The photon changes direction, looses partial energy. • The electron is kicked out of the atom. • The electron & the scattered photon cause further ionization.

  7. (3)-Interaction of  with matter:- pair production: i-It is possible when the incoming photon energy is above 1.02 MeV. ii-The photon disappeared in the field of the nucleus & replaced by an electron-positron pair. iii-The positron is a positively charged particle with a mass of normal electron. iv-When it reaches its final track, it combines with a normal negative electron in a process known as annihilation.

More Related