BARTINGTON INSTRUMENTS
Page 70 of 82 OM0408/49
20.7. Low Temperature Measurements
These will usually be performed using the larger sample size and without the furnace. The T
thermocouple can be connected just above the toggle switch on the MS2WF furnace, shown in
Figure 35, and is used for low temperature measurements.
The sample can be attached to the tip of the type ‘T’ thermocouple using plasticine. When taking
low temperature measurements the furnace heater is not used, so the MS2WFP controls can be
set to RESET, HOLD and dial=0.
Connect the T thermocouple, and select this type on the furnace switch. The sample should then
be cooled, using liquid nitrogen or similar, to the lowest temperature required. Following cooling
the sample should be placed in the MS2W sensor. The sample will then warm up naturally to
room temperature, and readings can be taken in increments as the temperature increases.
During this operation the sensor aperture can be horizontal or vertical, whichever is more
convenient.
Figure 35. Connection for T type Thermocouple
Note:
The sensor should be orientated horizontally for these measurements.
WARNING:
The glass tube of the MS2W sensor may be damaged if a tightly fitting sample
is inserted. Use only the recommended sample size. If other components/objects are to be
placed within the cavity, ensure that they will not expand on recovery to room temperature
and damage the glass. Smaller samples can be used for low temperature measurements
within the furnace. The type ‘T’ thermocouple will be used and the furnace controller
switched from RESET to RAMP or SET as the temperature passes through zero.
20.8. GeoLab
The GeoLab program supplied prompts the operator to select the correct thermocouple, and
to set the power supply to a rising or falling ramp, and collects the magnetic susceptibility
measurements as a function of temperature. See the Geolabsoft manual, OM0004, for further
information.
