There is another mechanism by which beta particles loss energy via production of electromagnetic radiation. From classical theory, when a charged particle is accelerated or decelerated, it must radiate energy and the deceleration radiation is known as the bremsstrahlung (“braking radiation”). The beta particles follow a very zig-zag path through absorbing material, this resulting path of particle is longer than the linear penetration (range) into the material.īeta particles also differ from other heavy charged particles in the fraction of energy lost by radiative process known as the bremsstrahlung. Therefore their path is not so straightforward. Moreover, beta particles can interact via electron-nuclear interaction (elastic scattering off nuclei), which can significantly change the direction of beta particle. Modified Bethe formula for beta particles. For high energy electrons an similar expression has also been derived by Bethe to describe the specific energy loss due to excitation and ionization (the “collisional losses”). Since the beta particles mostly reach relativistic energies, the nonrelativistic Bethe formula cannot be used. Their mass is equal to the mass of the orbital electrons with which they are interacting and unlike the alpha particle a much larger fraction of its kinetic energy can be lost in a single interaction. In comparison with alpha particles, beta particles have much lower mass and they reach mostly relativistic energies. Nature of an interaction of a beta radiation with matter is different from the alpha radiation, despite the fact that beta particles are also charged particles. Annihilation (only positrons) Comparison of particles in a cloud chamber.Inelastic collisions with atomic electrons (Excitation and Ionization).Nature of Interaction of Beta Radiation with Matter By 1934, Enrico Fermi had developed a Fermi theory of beta decay, which predicted the shape of this energy curve. Beta particles can therefore be emitted with any kinetic energy ranging from 0 to Q. The shape of this energy curve depends on what fraction of the reaction energy ( Q value-the amount of energy released by the reaction) is carried by the massive particle. This characteristic spectrum is caused by the fact that either a neutrino or an antineutrino is emitted with emission of beta particle. The beta emission has a characteristic spectrum. This emission is accompanied by the emission of antineutrino (β- decay) or neutrino (β+ decay), which shares energy and momentum of the decay. In the process of beta decay, either an electron or a positron is emitted. The following table shows the similarities and differences between alpha particles, beta particles and gamma rays.Spectrum of beta particles The shape of this energy curve depends on what fraction of the reaction energy (Q value-the amount of energy released by the reaction) is carried by the electron or neutrino. Gamma radiations are electromagnetic radiations with high energy and high penetration capacity produced from a radioactive material after the gamma decay. Gamma rays: They are also called gamma radiations.
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