FEI Quanta FEG 250, Руководство пользователя

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System Options: Heating Stage 1000 °C / Heating Stage 1500 °C
9-44
151 - Temperature Calibration
This is the supervisor alignment procedure. The HS 1000 assembly is
calibrated by melting the silver sample (962 °C), the HS 1500
assembly is calibrated by melting the gold sample (1064 °C). The
calibration samples are a part of accessory.
The HS assemblies are factory calibrated with the standard ceramic
crucible, at 400 Pa chamber pressure, under a water environment and
with the ramp rate 10 K/min. At these conditions the temperature shift
should be less than 50 K. In other case, contact your local FEI service
representative.
Note :
Different pressure, environment and fast ramp speeds lead to a less
accurate sample temperature readout and to incompatible results.
Checking Calibration
The HS assembly calibration typically does not change over the
heater lifetime. However, if greater precision is required in the actual
temperature read-out follow the procedure:
1. Put a small piece of calibration sample onto the standard ceramic
crucible.
2. Move the stage about 10 mm from the centre position to protect
the sample to be blown away during pumping.
3. Pump down the chamber. Obtain the sample image onscreen.
4. Start the 151 - Temperature Calibration alignment.
5. Reach the temperature 100 K below the expected melting point
(50 K/min ramp rate can be used).
6. Slower the ramp rate to 10 K/min and set the target temperature
about 10 K above the expected melting point.
7. Observe the sample and stop ramping just when the sample melts.
Enter obtained temperature to the
Ag / Au melting point: /
Measured edit box.
By finishing the procedure, the temperature readout is corrected to
match the theoretical value. A readout at a room temperature is not
influenced and linear interpolation is applied between these points.
Other samples with a verified Theoretical melting temperature (note
the vacuum and chamber environment conditions could influence it)
can be used in the
User-defined calibration point: edit boxes. This
introduces another point to the calibration profile.
HEATING STAGES BASIC OPERATIONS
Setting up a Temperature Profile
The temperature profile is a series of heating cycles consisting of a
setpoint temperature, ramping rate and soaking time. The controller
performs each cycle in succession, starting with the first setpoint and
going through each one until finished. This feature is useful for
performing dynamic experiments with specific temperatures and
heating times.
In the temperature profile example (see below) there are four
setpoints defined, each with its own ramp and soak time. The ramp
(Rn) and soak (Sn) periods are pointed out.