5-1 |
The underlying principles of E-beam technology |
L. A. BRABY, Dept. of Nuclear Engineering, Texas A&M Univ., 58-R Zachry Engineering Ctr., 3133 TAMU, College Station, TX 77843-3133 X and gamma ray irradiation have been used very effectively for pasteurization, and sometimes sterilization, of many foods. Radiation is effective because it produces strand breaks and other damage in the DNA of microorganisms, and prevents them from reproducing. X and gamma rays produce this DNA damage by first transferring their energy to electrons; then the electrons initiate the chemical changes. Thus it is possible to produce the same biological effects using high energy electrons directly. This has several advantages. In contrast to a gamma ray irradiation facility, there is no radioactive source involved; the electrons are produced by a relatively simple electronic machine that produces no radiation when it is turned off. Direct use of electrons is also much more efficient than using x rays because x ray production starts with high energy electrons, and the process of converting the electron energy to x rays (called Bremsstrahlung) is very inefficient. However, electrons have relatively short range in most materials, so the material treated must be relatively thin, and the shape of the material may have to be carefully planned to obtain the desired dose distribution. Techniques for controlling the dose distribution and methods for predicting the results will be discussed.
Session 5, E-Beam technology: Where are we in terms of the science?
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