Radiation measuring devices

Counter, Geiger-Mueller (GM counter)—Highly sensitive, gas-filled radiation-measuring device to detect (count) individual photons or particulate radiation. 

All photochemical equipment including lamps, filters, radiation measuring devices... 

The radiation measuring unit built into the weathering device must be calibrated at regular intervals. Two methods are commonly used for this purpose either a calibrated xenon lamp is used, which generates an irradiance indicated in the calibration certificate on the surface of the samples at a specific level of electric power, or the radiation measuring device must be recalibrated by the manufacturer at regular intervals. 

Depabna, M. S. Phototranschromic compositions, multi-color ultraviolet radiation measurement devices useful as sunburn dosimeters using them, and the use and fabrication of the dosimeters. Eur. Pat. Appl. 325863, 1989 Chem. Abstr. 1990,112, 32735. 

Free-standing films can be produced of parylene. These ultrathin (250A-3 microns) films, called pellicles, are used as beam splitters in optical instruments, windows for nuclear radiation measuring devices, dielectric supports for planar capacitors, and for extremely fast-responding, low-mass thermistors and thermocouples. 

Process Monitoring Equipment 2.2.4.3.1 Radiation Measurement Devices... 

Although the devices outlined above are the most commonly used for evaluating total alpha, beta, and gamma radiation, other methods and other devices can be used. In addition, local conditions (i.e., temperature, humidity) or the properties of the specific radionuclides emitting the radiation may make other types of devices or other methods more optimal to achieve the goals of the survey than the devices noted above. There, experts or individual vendors should be consulted to determine the appropriate measurement device for any specific application. 

Two main principles of temperature measurement use thermocouples and the so-called resistance thermometer. In chemical plants both methods were applied because they are easy to fit and to maintain.The accuracy of the measurement is influenced by, for example, radiation, which must be taken into account. Thermocouples can be inserted into the pressure system using special sealing techniques, or they may be mounted within a protective tube which is introduced into the pressurized volume. Thermocouple-wires are usually protected with an isulating input in closed-end capillaries with outer diameters of at least 0.5 mm. Thermocouples are technically well tested for pressures up to 6 kbar and temperatures to approx. 800°C. Above these ranges the exact measurement is negatively influenced by several parameters, and the deviations must be taken into account. The accuracy of the temperature measurement devices is normally better than 1 °C. 

The temperature measurement devices which do not contact the hot surfaces, for example, optical -, radiation pyrometers, and infrared techniques, are not typical for high-pressure application. 

This discrepancy between the apparent level, in the gauge glass, and the actual level (see Fig. 6.1), in the tower, also occurs in any other type of level-measuring device. This includes external float chambers, kidneys, displacement chambers, and level-trols. The one exception to this is level-measuring devices using radiation techniques. 

OPTICAL EMISSION SPECTROCHEMICAL ANALYSIS. In this analytical technique, an optical device is used to analyze radiation from electrically excited sample atoms. The analyzing device provides monochromatic images whose intensities are measured and related to the concentration of the elements within the sample that produces the specific radiation measured. The technique is precise and rapid, and adaptable to solid, powder, or liquid samples. 

All methods of radiometric analysis involve, of course, the use. of various radiation detection devices, The devices available for measuring radioactivity will vary with the types of radiations emitted by the radioisotope and the kinds of radioactive material. Ionization chambers are used for gases Geiger-Miiller and proportional counters for solids liquid scintillation counters for liquids and solutions and solid crystal or semi-conductor detector scintillation counters for liquids and solids emitting high-energy radiations. Each device can be adopted to detect and measure radioactive material in another state, e.g., solids can be assayed in an ionization chamber. The radiations interact with the detector to produce a signal,... 

The measuring device is Robertson-Berger broadband filter UV radiometer (RB-biometer). The time series of 10 min sums obtained during August 1, 1996 to June 25, 1997 was supplemented by (i) daily averages of total ozone concentration measured by Dobson spectrophotometer in HK [17, 18], (ii) hourly totals of global solar radiation measured by a Kipp-Zonen CP-11 in HK, and hourly fractions of sunshine... 

The use of radiation dispersal devices, commonly referred to as dirty bombs, is particularly concerning for disaster planning and emergency preparedness personnel. An RDD is an explosive device designed to spread radioactive material without a nuclear explosion (Briggs Brinsfield, 2003). The initial blast from the explosion can kill or inflict mechanical trauma on those who are close in proximity to the explosion while the radioactive material is dispersed. Please refer to chapter 27, Radiological Incidents and Emergencies, for further information on decontamination, radiation sickness, and personal protective measures. 

Photomultipliers, charge coupled devices (CCDs) and avalanche diode detectors are able to detect single photons over the visible to near-IR range with efficiencies approaching unity. The arrival of photons at a detector is not correlated, due to the quantum nature of electromagnetic radiation. Measurements of intensity as the averaged sum of photon events has a well-defined stochastic variance associated with a Poisson distribution. This variance scales as the square root of the number of photons. 

A difference in irradiation uniformity can be observed between higher and lower settings of lamp power (Fig. 3A and B) (17) or when the lamp or filters are changed. The result of the irradiation intensity mapping will to a certain extent also be dependent on the spectral sensitivity of the measuring device due to wavelength-dependent reflection or scattering of the incident radiation. 

An electronic measuring device is used for the measurement of quantities such as illuminance. It is composed of an amplifier, sensing device, filters, and a readout device. The ICH document does not specify which of the several different detector heads and filters available should be used. Photometric measurements are all weighed for human vision and as such do not measure the true amount of incident radiation. Table 1 listed the correction factors that are applied for a photometric detector and Figures 4 to 6 show how these corrections distort the actual data obtained (29). 

A radiometer is an electronic measuring device which when coupled to a proper sensing device, e.g., flat response radiometric detectors (quantum) and calibrated, measures most accurately the quantity of incident radiation falling on its sensor. These instruments are available for both the UV or VIS ranges. 

Most assuredly, a number of sources may prove that a drug substance/product is photolabile as studies have shown (42,43). However, will they generate the same degradation products and in the same amounts Studies by Thoma and Kerker (44,45), Sequeria and Volzone (14), Merrifield et al. (46) and Baertschi et al. (41) have shown this not to be the case. One cannot ignore the SPD of the source or whether the dosage measurement device, be it a radiometer or chemical actino-meter, measures all of the incident radiation or only part of it as pointed out in Chapter 3, Figures 3 through 7 of this book. 

The temperature of a substance in a particular state of aggregation (solid, liquid, or gas) is a measure of the average kinetic energy possessed by the substance molecules. Since this energy cannot be measured directly, the temperature must be determined indirectly by measuring some physical property of the substance whose value depends on temperature in a known manner. Such properties and the temperature-measuring devices based on them include electrical resistance of a conductor (resistance thermometer), voltage at the junction of two dissimilar metals (thermocouple), spectra of emitted radiation (pyrometer), and volume of a fixed mass of fluid (thermometer). 

A temperature measuring device indicates the temperature of its sensor, which is supposed to be, but is not necessarily, the temperature of Che medium that the sensor is in contact with. When a thermometer (or any other temperature measuring device such as a thermocouple) is placed in a medium, heat transfer takes place between the sensor of the thermometer and the medtum by convection until the sensor reaches the temperature of the medium. But when tlie sensor,is surrounded hy surfaces that arc at a different temperature than the fluid, ra diaition exchange also takes place between the sensor and the surrounding surfaces. When the heat transfers by convection and radiation balance each other, the sensor indicates a temperature that falls between the fluid and surface temperatures. Below we develop a procedure to account for the radiation effect and to determine the actual fluid temperature. 

Cesium compounds have relatively few commercial uses. Cesium bromide is used to make radiation detectors and other measuring devices. Cesium carbonate and cesium fluoride are used to make specialty glasses. Cesium carbonate and cesium chloride are used in the brewing of beers. Cesium compounds are also used in chemical research. 

There are many more design and control features to these facilities that aid in their management such as air circulators for mixing the contents, multiple-level and density detectors, temperature measuring devices, radiation alarms, etc. Although we do not take credit for these features as primary phases of confinement of the waste, we do rely on these control systems to ensure the primary barriers or phases are functional. 

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