Nuclear level detector radiation

After the dismantled equipment had been trucked away, my boss said, "And where, Lieberman, is the nuclear level detector radiation source 1 imagine even you must realize that these radioactive sources are licensed. God help us if you have lost it."... 

Measurements of liquid density are closely related to quantity and liquid-level measurements since both are often required simultaneously to establish the mass contents of a tank, and the same physical principle may often be used for either measurement, since liquid-level detectors sense the steep density gradient at the liquid-vapor interface. Thus, the methods of density determination include the following techniques direct weighing, differential pressure, capacitance, optical, acoustic, and nuclear radiation attenuation. In general, the various liquid level principles apply to density measurement techniques as well. 

When detecting the interface between two liquids, electrical conductivity, thermal conductivity, opacity, or sonic transmittance of the liquids can be used. Interface-level switches are usually of the sonic, optical, capacitance, displacer, conductivity, thermal, microwave, or radiation types. Differential pressure transmitters can continuously detect the interface, but, if their density differential is small relative to the span, the error will be high. On clean services, float- and displacer-type sensors can also be used as interface-level detectors. In specialized cases, such as the continuous detection of the interface between the ash and coal layers in fluidized bed combustion chambers, the best choice is to use the nuclear radiation sensors. 

Ultra-pure materials are needed for the constmction of the next generation of ultra-low level radiation detectors. These detectors are used for environmental research as well as rare nuclear decay experiments, e.g. probing the effective mass and character of the neutrino. Unfortunately, radioactive isotopes are found in most construction materials, either primordial isotopes, activation/spallation products from cosmic-ray exposure, or surface deposition of dust or radon progeny. 

Low-level radioactive waste gives off small amounts of ionizing radiation, is usually generated in small quantities, and need only be safely stored for relatively short periods of time due to the half-lives of the radioisotopes involved. Low-level nuclear waste includes such things as contaminated laboratory clothing, cleaning equipment and supplies, medical waste that is radioactive, and discarded radioactive devices such as smoke detectors. It is only necessary to safely store this waste for periods of 100-500 years. Prior to about 1979, most waste of this type was sealed in steel drums and dumped into the ocean. Current procedures require that such waste be stored in steel drums and buried in secure sites under several feet of soil (Figure 13.14). 

Glass samples are placed in plastic vials and irradiated in the neutron flux of a nuclear reactor. Short irradiation times produce low levels of residual radiation, enabling the samples to be handled safely within a few days of analysis. Data are acquired by a germanium detector and multichannel analyzer. Most... 

Artificial sources of radiation are commonly used in industry, research, medicine, nuclear power plants (NPP), etc. Some workers are exposed to natural sources, for example, in mines and other conditions where the radon concentration in air might be higher than in normal cases. Relatively high dose rates are measured during air travel due to the elevated levels of cosmic rays at high altitudes. This means that many people are exposed in their work. Some of them are monitored individually, for example, by a small photographic film, thermoluminescent material, or portable electronic devices. These types of detectors on the body register the dose due to the external sources and yield an estimate of the dose received by the wearer. 

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