Bruker Anton Paar, User Manual

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General Remarks
20 DOC-M88-EXX268_V1_12.2016
Some features of environmental heaters are:
• Convection (at lower temperatures without vacuum) and radiation heating (at high
temperatures or under vacuum) are used.
• A crucible can be used to hold the sample.
• Different chemically inert sample holders are provided.
• A sample rotation is possible.
• Easy sample exchange.
• The heater surrounds the sample.
• Homogeneous temperature profile around the sample.
• Lower heating rates (< 60 °/min).
2.2 Temperature Measurement and Calibration
2.2.1 Temperature Measurement
The way of temperature measurement and the type of temperature sensor depend on the
temperature range of the device.
In the low temperature range around ambient temperature and down to -263 °C, Si-diodes
are used as sensors for measurements.
From LN2-temperature (-196 °C) to 450 °C Pt100 resistors and Type K thermocouples are
widely used, the latter are useful up to 1150 °C.
Above ambient temperatures up to 1600 °C Type S thermocouples (Pt/Pt-10%Rh) are
standard. The recommended highest temperature ends at 1450 °C because at higher
temperatures diffusion processes change the chemism which can lead to wrong values.
Above 1450 °C type S thermocouples should be used no longer than 3 hours continu-
ously.
Type D (W-3%Re / W-25%Re) thermocouples are used from ambient temperature up to
highest temperatures. They require a high vacuum (<10
-4
mbar) or oxygen free atmos-
phere to avoid destruction. Once heated to highest temperatures, they become brittle and
break very easily.