Factors that Affect Radiation Measurement

Radioactive tracer techniques have long been used to study particle motion in solids fluidization systems. The advantage of this technique is that the flow field is not disturbed by the measurement facility and, therefore, the measurement of the motion of the tracers represents the actual movement of particles in the system. The tracer particles are usually made of gamma-emitting radioisotopes, and their gamma radiation is measured directly by scintillation detectors. Factors that affect gamma radiation measurement were identified as the characteristics of the radiation source, interactions of gamma rays with matter, the tracer s position relative to the detector, detector efficiency, and dead time of the measurement system. 

Atmospheric—Atmospheric corrosion is responsible for a large fraction of the total corrosion in the world. Factors that affect the atmospheric corrosion of materials in a marine environment are the time of wetness, temperature, material, atmospheric contaminants and pollutants, solar radiation, composition of the corrosion products, wind velocity, and biological species [fO]. Atmospheric corrosion of a passive alloy tends to be localized. For electrochemical processes related to corrosion to occur, an electrolyte must be present to allow current to pass via diffusion and electrochemical migration of cations and anions. Seawater is a very conductive electrolyte. The severity of corrosion in an atmospheric environment is related to the time of wetness during which electrochemical processes and corrosion take place. There is also a direct relationship between atmospheric salt content and measured corrosion rates [/O]. 

Premature ovarian failure is defined by the presence of at least 4 months of amenorrhea and at least two serum FSH concentrations measuring greater than 40 lU/L (obtained at least 1 month apart) in women younger than 40 years of age. A complete history should be taken regarding other factors that can affect ovarian function such as prior ovarian surgery, chemotherapy, radiation, and autoimmune disorders. In patients with primary amenorrhea, particular attention should be paid to breast and pubic hair development according to... 

Many factors affect a gamma radiation measurement (Knoll, 1979 Tsoulfanidis, 1983). The most important factors relevant to the CAPTF are the characteristics of the radioactive source, the interaction of gamma rays with matter, the position of the source relative to that of the detector, the efficiency of the scintillation detector, and the dead-time behavior of the whole measurement system. These factors are separately discussed in the following subsections. 

The most important elements affecting the energy resolution of a radiation detection system are the three statistical factors mentioned above in relation to the width F. It is worth repeating that in energy measurements it is the energy resolution of the counting system (detector-preamplifier-amplifier) that is the important quantity and not the energy resolution of just the detector. 

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