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Alexandrite Effect Spectropyrometer

Alexandrite effect spectropyrometer (US Patents 7,004,624 and 7,052,177)

The alexandrite effect spectropyrometer measures the relative spectral power distribution of a radiating body in the wavelength range of 380 - 760 nm, integrates the relative spectral power distribution in the wavelength range, and determines its thermal temperature by the patented methods. It can directly measure high to ultrahigh temperature from 800 K to 100,000 K of any radiating bodies, such as blackbody, gray bodes, combustion chambers, gas turbines,  plasma jets, flames, electric arcs and discharges, furnaces, metals and ceramics etc. At present, the spectropyrometer is the only instrument that can directly measure temperature over 4000 K. The spectropyrometer can directly measure high to ultrahigh thermal temperature of plasma jets, electric arcs and discharges, and high temperature flames up to 100,000 K. The spectropyrometer is rugged to perform in the harshest measurement environments.

The alexandrite effect spectropyrometer measures the relative spectral power distribution of a target to determine its temperature, thus, the emissivity of the measured target is not required for accurate temperature measurement. Whatever the emissivity of a target is, the spectropyrometer normalizes the spectral power as 1 at 560 nm, and then calculates the temperature from the relative spectral power distribution. If a group of gray bodies, for example, have emissivities at 0.3, 0.6, and 0.9, their relative spectral power distributions are the same as that of blackbody at the same temperature, therefore, the measured temperature by the spectropyrometer is the same as that of blackbody, however, the spectropyrometer does not need the emissivities of the gray bodies to determine their true temperature.  

The alexandrite effect spectropyrometer has a spectral correction function, a sequential temperature measurement function, and a temperature output port. The spectral correction function can be used to correct spectra for accurate temperature measurement of the targets with spectral lines and/or background noise. The sequential temperature measurement function can be used to measure a target continuously with a time interval as short as 10 ms, and the measured temperatures and spectra are saved for industrial applications and spectroscopy study.  

By using the sequential temperature measurement function, the spectropyrometer can measure a temperature distribution by one measurement, and can measure temperature of a target emitting radiation in a very short time, such as an electric discharge. The minimum measurement time of the spectropyrometer is 1 ms, minimum measurement interval is 10 nm, and the maximum measurement rate is 100 times per second (100/s). 

The temperature output port is compatible with other industrial and scientific equipment for temperature control and other purposes. The spectropyrometer can also continuously outputs spectra to monitor a target for determining whether a processing is normal or a criterion is over limit.




Temperature ranges:

            LASP 0280:    800 1,200 K

            LASP 1280:    1,000 2,500 K

            LASP 2280:    1,800 5,000 K

            LASP 3280:    3,000 10,000 K

            LASP 4280:    5,000 50,000 K

            LASP 5280:    10,000 100,000 K

Wavelength range:      380 -760 nm

Temperature resolution:              1 K

Wavelength resolution:                1 nm

Minimum measurement time:        1 ms

Minimum measurement Interval:   10 ms

Maximum measurement rate:       100/s


            < 0.5% for targets with continuous spectral emissions

            < 1.0% for targets with spectral lines

Temperature Scales: Kelvin, Celsius and Fahrenheit


Optical Receivers


1. Optical Viewing System:

      Focal Length:                  1.5 m -  m (0.1m with a close-up lens)

      Working Distance:            1.5 -  m

      Measurement Angle:         1.00




2. Collimator:

      Focal Length:                  700 mm

      Working Distance:            1.0 -  m

      Objective:                      20x

      Minimum Target Size:       1mm at 1000 mm





3. Collimating Lens:

      Focal Length:                 100 mm

      Diameter:                      25.4 mm





4. Fiber Optic-Coupled Lens:

      Focal Length:                10 mm

      Diameter:                     5.0 mm




5. Integrating Sphere:

      Diameter:                    38.1 mm

      Sphere Coating:           Spectralon

      Input Port:                  9.5 mm




6. Flame Fiber Optic Probe:

      Fiber Diameter:            400 mm

      Numerical Aperture:      0.22

      Operation Temperature: Up to 700 oC




Optical Windows:


1. Cubic Zirconia (CZ) Window

    Diameter:            10 mm

    Thickness:           1, 2, 5, 10 mm

Properties: High melting point, high thermal shock resistance, hard



2. Heat absorption glass window

    Diameter:            10 mm

    Thickness:           1, 2, 5, 10 mm

Properties: Heat absorption



2. Quartz Glass window

    Diameter:            10 mm

    Thickness:           1, 2, 5, 10 mm

Properties: High spectral transmittance,



Operating Conditions:

            Temperature:   15 - 35 oC

            Humidity:        Below 80%




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Last modified: 01/22/15.