5. TYPES OF INTERACTION WITH MATTER:-
3- Compton scattering
Imp in diagnostic radiology
6. COHERENT SCATTERING:-
-In this type of interaction X- ray photon
having energy less than about 10ke may
undergo change in direction without any
change in their wavelength.
7. Types of coherent scattering :-
There are five 2 types –
2- Rayleigh scattering
1-Thomson scattering:- single electron is
involved in this interaction .kinetic energy and photon
energy don not changes as a result of the scattering
8. Rayleigh scattering:-
Whole electron involved in this interaction.
Both interaction may be described in terms of wave particle
interaction and are called classical scattering.
9. COHERENT SCATTERING:-
.As shown in fig1.1,when low energy X-ray photon passes near
the low binding energy outer shell electron of the atom.
*The photon interact with the electron & causes the vibration in
the electron .
*The process one is one the resonance such that electron vibrate
at a frequency corresponding to that of an X-ray photon.
*This is an unstable state and electron radiate energy in all
*And the atom returns to its uninterrupted state.
*But in this process no energy is transferred.
10. *This is only one process that does not cause
*scattering radiation in all direction without change in
their wavelength & any absorption
11. INCEDENT X- RAY PHOTON
3rd phase Photon emission
λ-2 Scattered x
1st-phase Photon absorption
2nd phase Excitation of atom λ1= λ2
12. PROBILITY OF COHERENT SCATTERING
-It will increase with………
1.Low atomic number
2. Lower photodisintegration >10kev
1. It produces scattered radiation
2. It can contribute to film fog
13. PHOTOELECTRIC EFFECT:-
.The photoelectric effect interaction occurs when the
energy of an an incident photon have slightly grater than
the binding energy of the electron .
.When the incident X-ray photon interact with an inner
shell electron, the total energy is absorbed by electron
resulting in the ejection of from the atom .
.After the ejection of atom , the atom is ionized .
.This state of the atom is highly unstable, so the inner shell
vacancy immediately filled by inner shell of orbit than atom
ia stable state .
15. When the electron drops into the inner shell vacancy ,
the energy is released in the form –
1. characteristic X-ray
1.PE Absorption does not produce scattered radiation.
1.Patient does is higher
16. COMPTON SCATTERING:-
*In this type of interaction, an incident of
photon having moderate energy strikes with
an outer shell electron of an atom and eject an
electron from orbit .
*The photon is deflected by an elelctron so
that it travels in a new direction as scattered
scattered e- known as the RECOIL e-
18. DISADVANTAGES OF COMPTON
.It reduces film contrast because ethes e
photons have excellent chance to reach upto
xray film and produce film fog
. These photon are energic as primary photons
so they can reach upto personel working near
19. PAIR PRODUTION :-
.The process is example for the conversion of the
energy into mass .
.A photon having an energy >1.02Mev,
. When a high energy electron photon intract with
the nucleus of th eatom .
It energy is converted into the matter from of two
the positron entract with electron of medium and
transferred back to radiation energy
21. This radition is also called
used in positron emission tomography
PROBABILITY OF PAIR PRODUTION
.The probability of pair production increase
with atomic number (z2) of the given
22. PHOTO DISINTEGRATION:-
.Very high energy x ray 7-10Mev absorbed
directly by the nucleus .
.the photon energy directly absorbs that
resulting in the ejection of an neutron ,protron
or rarely an alpha particle .
.Photodisintegtaion does not occur with
energy less than 7Mev . It has no diagnostic