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Radiation thermometer

The ITS-90 has its lowest point at 0.65 K and extends upward without specified limit. A number of values assigned to fixed points differ from those of the immediately previous scale, IPTS-68. In addition, the standard platinum resistance thermometer (SPRC) is specified as the interpolation standard from 13.8033 K to 961.78°C, and the interpolation standard above 961.78°C is a radiation thermometer based on Planck s radiation law. Between 0.65 and 13.8033 K interpolation of the scale rehes upon vapor pressure and constant-volume gas thermometry. The standard thermocouple, which in previous scales had a range between the upper end of the SPRT range and the lower end of the radiation thermometer range, has been deleted. [Pg.399]

Blackbody radiation law proposed by J. Stefan form the basis for the radiation thermometers, with Planck s law. The radiation law is strongly nonlinear in temperature, since it depends on T4... [Pg.192]

B. Kraus, M. Kaiser, Radiation thermometer and method of computing the temperature , U.S. Patent 6149298 (2000)... [Pg.80]

Radiation thermometers, 24 453 calibration of, 24 454 calibration source for, 24 458 Radiation thermometry, uncertainty of,... [Pg.784]

ITS-90 platinum resistance thermometer range, 24 444-447 ITS-90 radiation thermometer range, 24 452-455... [Pg.926]

The Broadband Radiation Thermometer (Total Radiation Pyrometer)... [Pg.475]

In the category of electronic thermometers, the thermocouples (TCs), resistance temperature detectors (RTDs), thermistors, integrated circuitry (IC), and radiation thermometers will be discussed in separate subsections. The IC and diode detectors will be discussed in connection with cryogenic thermometry. Their characteristics are shown in Figure 3.161. [Pg.496]

A polished TiO2(110) wafer of 6.5 x 1 x 0.25 mm3 (Earth Chemical) was used after deposition of Ni film on the rear side of the sample to resistively heat the sample on a sample holder. The surface was cleaned by cycles of Ar + ion sputtering (3 keV for 3 min) and annealing under UHV at 900 K for 30 s until a clear lxl LEED pattern was obtained. Deuterated formic acid (DCOOD, Wako, 98% purity, most of the contaminant is water) was purified by repeated freeze-pump-thaw cycles and introduced into the chamber by backfilling. The surface temperature of the crystal was monitored by an infrared radiation thermometer. [Pg.36]

The three most important types of thermometers are expansion-type thermometers (pressure thermometers), electrical thermometers, and radiation thermometers. In expansion-type thermometers the primary sensing element is a bulb containing an expansible fluid. The bulb is connected to a pressure spring through capillary tubing. Expansion of the thermometric fluid with rising temperature causes expansion of the pressure spring, which in turn is converted to a mechanical displacement as the final measure of temperature. The response of these thermometers... [Pg.56]

The temperature of solid specimens in the plasma was determined by means of an infrared radiation thermometer (Infrascope Model 3-1C00, Huggins Laboratories Inc., Sunnyvale, Calif.) attached to a chart recorder. This device employs a lead sulfide detector and suitable filters to permit remote measurement of 1.2 to 2.5/x radiation emitted by the specimen. Line filters and electrostatic shielding were employed to minimize interaction of the radiofrequency field with the infrared thermometer. To compensate for variations in emissivity and inhomogeneity in the optical field, empirical calibration curves were constructed based on measurements of new and partially oxidized graphite pellets in a con-... [Pg.240]

Blackbody radiation is achieved in an isothermal enclosure or cavity under thermodynamic equilibrium, as shown in Figure 7.4a. A uniform and isotropic radiation field is formed inside the enclosure. The total or spectral irradiation on any surface inside the enclosure is diffuse and identical to that of the blackbody emissive power. The spectral intensity is the same in all directions and is a function of X and T given by Planck s law. If there is an aperture with an area much smaller compared with that of the cavity (see Figure 7.4b), X the radiation field may be assumed unchanged and the outgoing radiation approximates that of blackbody emission. All radiation incident on the aperture is completely absorbed as a consequence of reflection within the enclosure. Blackbody cavities are used for measurements of radiant power and radiative properties, and for calibration of radiation thermometers (RTs) traceable to the International Temperature Scale of 1990 (ITS-90) [5]. [Pg.570]

The measurement equation of a spectral radiation thermometer may be approximated as... [Pg.587]

Radiation thermometers were developed for measuring temperatures higher than 1064°C they have the advantage that they are noncontact thermometers. Optical pyrometers measure apparent temperatures of objects by comparing the radiation from the objects over a narrow wavelength band with that of a standard, preferably using a photoelectric detector for the comparison. Corrections for the emissivity of the source must be made to determine the temperature the preceived temperature may be, and usually is, lower because all of the heat is not radiated. Total-radiation pyrometers measure the whole spectrum of energy radiated by the source. They are less accurate than optical pyrometers but can measure much lower temperatures (of the order of 100°C). This type of pyrometer also requires emissivity corrections. [Pg.296]

The total and spectral radiation thermometers are not really primary thermometers, since a one-point (or more) calibration is needed for thermodynamic temperature measurements. For that matter, magnetic thermometers also belong to this class—pseudoprimary thermometers. [Pg.1166]

Introduction. The relationship between the radiant energy emitted by an ideal (black) body and its temperature is described by Plancks radiation law. Radiation thermometers measure the radiation emitted by a body to determine its temperature. [Pg.1193]

Radiation thermometers can be sensitive to radiation in all wavelengths (total-radiation thermometers) or only to radiation in a band of wavelengths (spectral-radiation thermometers). Thermocouple and thermopile junctions or a calorimeter are the usual detectors in a total-radiation thermometer. For spectral systems, the classification is normally based on the effective wavelength or wavelength band used—as determined, for example, by a filter, which allows only near-monochromatic radiation to reach the detector, or by the use of a detector sensitive only to radiation in a specific wavelength band. Radiation thermometers utilize the visible portion of the radiation spectrum, infrared thermometers or scanners measure infrared radiation, and spectroscopic thermometers operate with radiation that is normally of shorter wavelength than the other two methods. [Pg.1194]

Principles of Radiation Thermometers. A detailed discussion on opto-electronic temperature measuring systems for radiance thermometers can be found in Ref. 48. In the USA, ITS-90 above the gold point is maintained by NIST [49]. A classical radiation thermometer is shown in Fig. 16.24. Radiation from the object whose temperature is to be measured is... [Pg.1194]

Reliability of Radiation Thermometers. Calibration of radiation thermometers at NIST is accomplished by focusing the radiance sensor at a blackbody furnace with known temperature. This blackbody furnace is previously calibrated by comparison calibration against a standard lamp, which, in turn, is calibrated at the gold point [52], With calibration performed at NIST, the accuracy of a radiation thermometer is within 0.4°C at the gold point, within about 2°C at 2200°C and about 10°C at 4000°C. [Pg.1196]

Other Radiation Thermometers Traditionally, radiation thermometers used a red filter to achieve a monochromatic comparison between the incoming radiation and that of a standard lamp. With the development of photomultipliers, better precision and automation are possible, including direct detection—eliminating the use of a standard lamp in actual applications. [Pg.1196]

The major problem in using a single wavelength radiation thermometer to measure the surface temperature is the unknown emissivity of the measured surface. The emissivity is the major parameter in the spectral radiance temperature equation (Eq. 16.28) for the temperature evaluation. Objects encountered for temperature measurements are often oxidized metal surfaces, molten metal, or even semitransparent materials. On these surfaces, the emissivity is usually affected by the surface temperature and the manufacturing process for these materials. [Pg.1196]


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See also in sourсe #XX -- [ Pg.1826 ]

See also in sourсe #XX -- [ Pg.10 ]




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