Double Ten science and technology about the basic problem of radiation measurement

Date:2022/8/1 8:52:38 / Read: / Source:本站

Double Ten science and technology about the basic problem of radiation measurement
In radiation measurement, the core of measurement is to reduce the error and improve the precision of measurement
The problem. Therefore, the following base wood issues must be considered.
The first is the illuminance of a continuous radiation source on a surface, and the distance from the radiation source to the receiving surface
Is represented by the inverse square law. Therefore, the ideal illuminance measurement must be able to accurately control the distance
Size, if the illuminance value of a radiation source at a certain distance is known, unless otherwise affected, at any distance
Illuminance can be calculated.
Secondly, according to the law of cosines, the actual projected area decreases proportionally with the increase of the incidence Angle. A certain
The radiation intensity over the area will vary depending on the Angle of incidence. Thus, in the physical measurement of irradiation or illumination
During the test, the probe needs to be corrected according to Lambert's law of cosines to calculate the actual value. Otherwise, it will produce
Considerable error, especially when the Angle of incidence is small, the error is larger.
Third, how to reproduce the response of the human eye to the spectrum. The unique response characteristics of the electronic probe are completely different from that of the state
International Commission on Lighting CIE Standard Observer. For this purpose, the probe must be able to correct the data by spectrum. Usually by different
Wavelength scanning, detection, or matching filters are used for this purpose.
In the scanning method, a monochromator or a multi-channel detector is used to measure the light intensity of each spectral line one by one, and the data root is measured
According to the visual function, the measurement results are obtained. The technique requires a microprocessor with a certain amount of sweep
Description precision, expensive, complex operation. In the scientific study of radiology and photometry, radiation technology is produced
This method is often used in industrial quality inspection, calibration and R&D.
The optical filter method provides a simple and economical solution. It only needs one photoelectric signal
Processing, therefore, requires only a single - channel electronic processor. Recent improvements in filter design technology
And the improvement of solid state detector technology has improved the accuracy of this technology in photometric measurement.
Filter matching involves adding a Colored glass Filter in front of the detector
The optical mirror can be selectively attenuated at different wavelengths until it fits the CIE visual function curve. Si for plane scattering
Photosensitive diodes, with good linear response and extremely high sensitivity in the visible spectrum range, are therefore rational
Think of a light detector. Using Si detectors, coupled with advanced filter design, the photometer can be achieved with the CIE
The best matching value of the function curve with only 1% error.
Finally, the measured detector realizes the conversion of electrical signals, and one of the most important parameters is accuracy
This is a numerical value defined by the CIE Institute as a function of the mean error of the photometric detector and CIE vision
The ratio gives this value. The highest precision, laboratory - grade precision detector
The matching between the detector and the filter is very precise, and once the matching is done, it cannot be matched
His detector/filter pairs are swapped. Each detector has a unique response signature that is required
Used in combination with filters of specific thickness and number of layers.
Once the response value of the detector has been determined, standard transfer techniques are used to correct it. Standard detectors are made of
The National Institute of Standards and Technology,
NIST). Position the detector/filter pair in front of a light source with a continuous output
For wavelength and intensity, tungsten halide lamps are generally used. In this way, the output electrical signal of the corrected detector is compared with the standard detection
The signal of the device is compared. Once the light response value of the detector is determined, a precise gain control can be matched
Make electronic amplifiers and data readout systems.


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