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The Medusa R is a blackbody primary source in which
radiation pyrometers can be calibrated. Specifically designed
to accommodate black body fixed point cells, the Medusa-R is
the optimal choice for primary labs needing the highest levels
of radiation measurement.
The temperature of the cavity can be set to ±0.1°C over the
temperature range 30 to 550°C. The controller reaches 550°C
approximately 45 minutes from switch on. Also, the cavity
temperature, as measured by a radiation thermometer took
approximately 45 minutes to reach stability from switch on.
The variation seen on the controller’s temperature
indication over a 5 minute period was ±0.2°C. Similar
variations were detected by a radiation thermometer looking
into the cavity.
Using a portable radiation thermometer having a target
diameter of 13mm, the 48mm target was surveyed. Maximum
temperature differences of ±1°C were found for set
temperatures in the range 100 to 500°C.
Temperatures along the inner 200mm of the 285mm long cavity
were measured at 400°C and 500°C, using a hand held
fiber-optic radiation probe. Maximum temperature differences
of ±4°C were found.
Large Fixed Point Cells can be fitted to the Medusa R
giving small uncertainties suitable for Primary Standards.
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