20 November 2010, R. Ubic
4
Raising the Voltage
All references to the screen refer to the left-hand monitor unless otherwise stated.
If the “Controller for JEM-2100/HR” software is not currently running, double click on the
TEMCON icon on the desktop of the left-hand monitor.
The beam current should be zero and the high voltage (HT) switched off unless the
microscope has recently been used, in which case the HT will be left on and beam
current non-zero.
If the anti-contamination device heater is in place, carefully unplug it and remove it.
Click on the HT button at the top of the screen.
While you are waiting for the high-voltage to stabilize, fill the anticontamination device
(ACD) dewar with liquid nitrogen.
For operation at 100 - 200 kV:
Use the
▲
and
▼
buttons to increase the kV setting to 100 kV. The
Step
option allows
you to control the step size of the changes.
Press the HT
ON
button and wait for the voltage to stabilize at 100 kV.
If the desired voltage is greater than 100 kV:
Click on the
More
box to obtain more options.
In the Auto HT section, set the
Target
voltage to the desired value. Again, the
step controller will allow you to change the size of voltage steps.
Set the
Step
size to 0.1 and the
Time/Step
to 3.
Press the
Start
button in the Auto HT section. If the target voltage is 200 kV,
then this will take about 50 minutes.
Once the HT stabilizes, the
beam current
(top left of screen) should be about
half the voltage (in kV)
µ
A (or about 101
µ
A at 200 kV).
If it is > 105
µ
A at
200 kV, contact Rick Ubic or Steve Letourneau and do not attempt to use the
microscope.
