Lake Shore Cryotronics CRX-6.5K, Руководство пользователя

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110 CHAPTER 5: Advanced Operation
Model CRX-6.5K Probe Station
5.2.2.5 Temperature Operation with the HT Sample Stage
The HT sample stage allows temperature operation of the sample above 350 K by
increasing the thermal isolation between the sample and CCR second stage. Recall
that the CCR second stage must not be operated above 350 K. The steps to cool the
Model CRX-6.5K probe station with the HT sample stage are the same for normal
operation; however, because of the increased thermal isolation between the HT sam-
ple stage and the CCR second stage, longer settling times should be expected when
controlling to a temperature setpoint.
Observe a 10 K/min ramping rate at all times for temperature changes. Failure to comply
may result in permanent HT stage damage.
5.2.2.5.1 Cooling the Probe Station with the HT Sample Stage
Follow this procedure to cool the probe station with the HT sample stage installed.
This procedure assumes the probe station is at room temperature and that the vac-
uum chamber has been evacuated following section 4.4.2.
1. Use the z-axis micrometers to raise all probes 3 mm to 4 mm above the sample
holder. Failure to do so will potentially cause damage to the probe tip or scratch
the sample surface.
2. Cool the probe station as described in section 4.5.2
5.2.2.5.2 Operating the HT Sample Stage from Base Temperature to 675 K
To operate the HT sample stage to 675 K, follow these procedures:
1. Use the z-axis micrometers to raise all probes 3 mm to 4 mm above the sample.
Failure to do so will potentially cause damage to the probe tip or scratch the
sample surface.
2. Use the controller settings given in TABLE 5-2 for operating the HT sample stage
above base temperature to set the P, I, and D and to set the proper heater range
for the temperature setpoint.
3. Change the setpoint for the HT sample stage (Model 336 temperature controller
Output 1) to the desired temperature.
Do not operate the HT sample stage above 300 K unless the probe station vacuum cham-
ber is closed, the system is under vacuum, and the CCR is operational to ensure there is
not a runaway temperature condition.
Observe a 10 K/min ramping rate at all times for temperature changes. Failure to comply
may result in permanent damage to the HT stage.
Operating the HT sample stage above 675 K may cause the CCR cold head and other com-
ponents in the probe station to exceed their maximum operating temperatures. This can
result in permanent damage to the Model CRX-6.5K probe station.
Probe arms that are thermally anchored to the sample stage and engaged for probing
over the HT sample stage will be subject to radiation and may be warmed to a tem-
perature exceeding their temperature maximum. Therefore, when probing a sample
temperature above 350 K, monitor the probe arm sensor reading to ensure the probes
and probe arms do not exceed 350 K. Depending on your measurement setup condi-
tions, you may need to remove the probe mount thermal anchors, or probe in inter-
vals. After each probing interval, retract the probes and/or lower the HT stage
temperature setpoint to reduce the radiative heat load and to cool them.
When operating the HT sample stage above 350 K, monitor the probe arm sensor to
ensure the probes do not exceed their maximum temperature.