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    4-Interaction of Radiation With Matter

    Uploaded by

    Malik Rashid Ali Langrial

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    © All Rights Reserved
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    4-Interaction of Radiation With Matter

    Uploaded by

    Malik Rashid Ali Langrial
    6 views6 pages

    Original Title

    4-interaction of radiation with matter

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    Copyright:

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    Download as ppt, pdf, or txt
    6 views6 pages

    4-Interaction of Radiation With Matter

    Uploaded by

    Malik Rashid Ali Langrial

    Copyright:

    © All Rights Reserved
    Download as PPT, PDF, TXT or read online from Scribd
    Download as ppt, pdf, or txt
    of 6

    INTERACTION OF RADIATION WITH

    MATTER
    • Statement:
    – As the particles passes through a solid, liquid or
    gas, it loses energy due to excitation and ionization
    of atoms and molecules in the matter.
    – The ionization may be due to direct elastic collisions
    or through electrostatic attraction
    • Range:
    – The distance which a radiation covers in a matter
    before coming to rest .
    • Dependence of interaction of radiation with matter:
    – Charge, mass and energy of the particles.
    – Density of the medium.
    4.Effect of radiation on matter:
    • Alpha particle is massive charged particle (about 7000
    times the mass of an electron). It interacts strongly with
    the matter causing intense ionization in it.
    • Beta particles being light can penetrate 100 times more in
    matter than alpha particles, but ionizing ability is 100 times
    less than α-particles.
    • Gamma rays do not carry any charge or mass. So they do
    not cause direct ionization in matter.
    5.Ways of interaction of radiation with mattre
    at different energies:
    • Photoelectric effect of particle if energy < than 0.5
    MeV
    • Compton scattering of particle if energy < than 1 MeV
    • Pair production of particle if energy > than 1.02 MeV.
    • In air γ-rays intensity falls off as the inverse
    square of the distance from the source, in
    much the same manner as light from a lamp .
    • In solids, the intensity decreases
    exponentially with increasing depth of
    penetration into the material.
    • The intensity I of a beam after passing
    through a distance x in the medium is
    reduced to intensity I given by the relation
    I  I 0e  x
    μ is the linear absorption coefficient of the medium .
    This coefficient depends on the energy of the photon as
    well as on the properties of the medium
    6.Fluorescence:
    • The property of absorbing radiant energy of high
    frequency and re-emitting energy of low frequency
    in the visible region of electromagnetic spectrum.
    • Examples:
    • Zinc sulphide
    • Sodium iodide
    • Barium platinocyanide

    7.Interaction of Neutron with Matter:


    • Neutron being uncharged particle does not ionize the matter.
    • It has maximum penetration power.
    • To stop a neutron, it must undergo direct collision with the nucleus.

    • a neutron must undergo a direct collision with a nucleus or some other particle that
    has mass comparable to that of the neutron. Materials such as water or plastic,
    which contain more low -mass nuclei per unit volume,

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