Beta particles penetrating power

The nuclear reactor also must be shielded against the emission of radioactive material to the external environment. Suitable radiation controls include both thermal and biological shielding systems. Radiation from alpha particles (a rays) and beta particles ((3 rays) has little penetrating power, but gamma rays have deep penetration properties. Neutron radiation is, however, the primary area of risk. Typically, extremely thick concrete walls are used as a neutron absorber, but lead-lined concrete and special concretes are also used. 

Gamma radiation has a very high penetrating power. A small fraction of the original stream will pass through several feet of concrete or several meters of air. The specific ionization of a gamma is low compared to that of an alpha particle, but is higher than that of a beta particle. 

Gamma rays (y) have high penetrating power and are not deflected by electric or magnetic fields. Beta particles ( 3) have a lower ionizing power and greater penetrating power than alpha particles (a). 

Which has the greatest penetrating power—alpha particles, beta particles, or gamma rays ... 

Because of their relatively large mass, a particles move slowly (up to only one-tenth the speed of light) and can be stopped by a few sheets of paper or by the top layer of skin. Beta particles, because they are much lighter, move at up to nine-tenths the speed of light and have about 100 times the penetrating power of... 

Beta particles are very small. They are fast moving electrons that are shot out of the nucleus of a radioactive element. They are easily stopped by a few sheets of paper, a thin sheet of metal or about 20 cm of air. Even the most energetic beta particle can only travel a metre or so in air before it is stopped. It has a penetrating power 100 times greater than alpha particles. You do not keep a radioactive element giving off this radiation in your pocket ... 

The discussion in this section is primarily based on Lind s book. Much of the early work in radiation chemistry was done either with radium sources and/or radon sources. These sources produced primarily alpha rays and weak beta rays. The lack of penetrating power of these particles made early experiments very difficult. 

Compare the penetrating powers of alpha particles, beta particles, and gamma rays. 

The three types of radiation vary in their penetrating power. Alpha particles are stopped by even a thin sheet of paper, but beta particles require thicker shields, such as a dense piece of wood. The energetic gamma rays are stopped only by thick blocks of lead or concrete. 

Radioactive decay is a process whereby unstable nuclei change into more stable ones by emitting particles of different kinds. Alpha, beta and gamma (a, P and y) radiation was originally classified according to its different penetrating power. The processes involved are illustrated in Fig. 1. 

In contrast to alpha emission, beta emission is characterized by production of particles with a continuous spectrum of energies ranging from nearly zero to some maximum that is characteristic of each decay process. The jS particle is not nearly as effective as the alpha particle in producing ion pairs in matte r because of its small mass (about /7(XK) that of an alpha particle), At the same time, its penetrating power is substantially greater than that of the alpha particle. Beta-particle energies are frequently related to the thickness of an absorber, ordinarily aluminum, required to stop the particle. 

A gas flow Geiger tube was used to count the and radiation from the films. The radiation from and H can be distinguished because the energies of the beta-particles emitted in each case, and thus their penetrating powers, are different. C radiation was detected through a thin Mylar window on the Geiger tube. H radiation does not penetrate this window. The window was removed to count the H and C radiation combined. The net counting rate for radiation was ob-... 

P (beta) - have greater penetrating power than an a particle but the ionization caused is less severe. 

Beta Particles A beta particle is an electron (negative charge) or positron (positive charge) separated from the nucleus of an atom. Smaller than alpha particles, beta particles travel at higher speeds and have enough penetrating power to pass through nearly 14 in. of human tissue. 

Ionising radiation by alpha particles (= He Mons). In comparison with beta and gamma radiation, alpha radiation has the least penetrating power and the highest linear energy transfer. Radionuchde that decays to a more stable nuclide by emission of an alpha particle. 

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