B3-KH12-B Article No and Article No supplement for th t Bevel-helical gear boxes B3

Flender/Flender Gear Units/Bevel-helical gear boxes B3

romagnetic spectrum, they also have severalcharacteristics in common. They are all waves with characteristic wavelength and fre- Irradiation 6 quency and certain amount of associated energy. The higher the wavelength, the smaller is the associated energy. The radio waves with long wavelengths of 3 cm to 3 km have very limited energy associated with them. Microwaves, although relatively low-energy waves, can cause mo-lecular vibrations in materials like food that contain moisture and fat and can result in very rapid heating. The - and gamma rays at the other end of the spectrum emit very- short-wavelength radiation and have very high associated energy levels. When made tobombard against materials, they can knock off an electron from an atom or molecule,causing ionization. For this reason, these are often called ionizing radiations . When food irradiation is discussed, it is mainly with respect to ionizing radiations. The energy associated with electromagnetic radiation is related to wavelength and frequency, as follows: Frequency /H1velocity of light/wavelength of radiation Energy /H1Plancks constant /H1frequency 2.2 Sources of Ionizing Radiations The main source of gamma radiation is cobalt 6, which is radioactive isotope produced from cobalt 5. second source is cesium 1, which is spent fuel of nuclear reactorsand also produces gamma rays. third source is -rays, which are stream of electrons. Since the associated energy levels of these rays are too low to have any practical valuein terms of radiation preservation, they need to be accelerated (in cyclotrons, linear acceler-ators, etc.) to make them acquire the required energy. Careful precautions should be takento ensure that all electrons have enough energy. If the acquired energy is too high, induced radioactivity in foods can occur with irradiation. 2.3 Units of Radiation 2.3.1 IntensityThere are two types of units for measuring radiation: intensity and dose. The intensity refers to the source and the dose