Radiation protection gamma rays

The sixth component of the system is the shield, which protects materials and workers from radiation, especially neutrons and gamma rays. 

When lead, which is very soft, is freshly cut, it has shiny blue-white sheen, which soon oxidizes into its familiar gray color. Lead is extremely malleable and ductile and can be worked into a variety of shapes. It can be formed into sheets, pipes, buckshot, wires, and powder. Although lead is a poor conductor of electricity, its high density makes it an excellent shield for protection from radiation, including X-rays and gamma rays. 

B.5.2 Relative Biological Effectiveness.The term relative biologic effectiveness (RBE) is used to denote the experimentally determined ratio of the absorbed dose from one radiation type to the absorbed dose of a reference radiation required to produce an identical biologic effect under the same conditions. Gamma rays from cobalt-60 and 200 to 250 KeV X-rays have been used as reference standards. The term RBE has been widely used in experimental radiobiology, and the term quality factor used in calculations of dose equivalents for radiation protection purposes (ICRP 1977 NCRP 1971 UNSCEAR 1982). The generally accepted values for RBE are provided in Table B-4. 

NCRP (1989b). National Council on Radiation Protection and Measurements. Medical X-Ray, Electron Beam and Gamma-Ray Protection for Energies Up to 50 MeV(Equipment Design, Performance and Use), NCRP Report No. 102 (National Council on Radiation Protection and Measurements, Bethesda, Maryland). 

SC 1-5 Uncertainty in Risk Estimates SC 1-6 Basis for the Linearity Assumption SC 1-7 Information Needed to Make Radiation Protection Recommendations for Travel Beyond Low-Earth Orbit SC 9 Structural Shielding Design and Evaluation for Medical Use of X Rays and Gamma Rays of Energies Up to 10 MeV SC 46 Operational Radiation Safety... 

The standard sources have been designed in order to allow the calibration of all the classical detectors of a, p, e, y, n, X radiation (ionisation chambers, Geiger-Miiller or proportional counters, scintillation or solid-state counters, etc.). They are classified as alpha sources, electron sources, beta sources, gamma sources, neutron sources. X-ray sources, heat flux sources, and sources for radiation protection dose meters. 

The description is based on reports from the Swedish National Institute of Radiation Protection (SSI, 1986a and 1986b). Since the end of the 1950s, 25 stations equipped with ionisation chambers 2.5 m above ground have been in operation by the Swedish National Institute of Radiation Protection (SSI). They register continuously the gamma radiation from both ground and cosmic rays. Only three stations transmit data automatically via telephone to a computer at SSI. 

The advent of efficient high-resolution gamma-ray detectors during the past decade has nearly eliminated the tedious radiochemical separation of each trace element from all others which was once necessary, although group separations are often a powerful aid to specificity and sensitivity. If the matrix itself is the major contributor to the activity (as with Ge or most III-V compounds), safety precautions may be necessary to protect the chemist against radiation. Many procedures have been published for matrix removal and for the separation of trace constituents (29.3.2.30). Ga, Ge,... 

Lead is a soft, malleable, and corrosion resistant material. Lead s high density makes it useful as a shield against x-ray and gamma-ray radiation and is used in x-ray machines and nuclear reactors. Lead is also used as a covering on some wires and cables to protect these from corrosion, as a material to absorb vibration and sound, and in the manufacmre of ammunition. Today most of the lead is used in production of lead-acid storage batteries, such as the batteries in automobiles. 

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