5 Putting HTK 1200N into Operation
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If the chamber is rotated too much relative to the
-
zero line of the diffractometer, the X-ray beam will
not pass through the alignment slit.
When the chamber is roughly aligned parallel to the
-zero line, replace the standard sample holder with
the alignment slit.
TIP: Refer to chapter 7.1 for information about ex-
changing the standard sample holder and the align-
ment slit.
Carry out the alignment as follows:
1. Put an appropriate beam attenuator in the pri-
mary beam path.
2. Generate a narrow X-ray beam (small beam
height) and select a detector area which is
larger than the beam.
3. Set the goniometer to
= 0 ° / 2
= 0 °.
4. Move the chamber to the
-zero line as follows:
If you have mounted the standard sample
holder:
•
Lower the chamber with the alignment stage
until no parts are in the X-ray beam path and
determine the maximum beam intensity
max
.
•
Lift the chamber until the X-ray beam is com-
pletely blocked and determine the background
intensity
bg
.
•
Move the chamber down until the beam intensity
= ½ • (
max
–
bg
), which means that the upper
edge of the alignment slit bisects the X-ray
beam.
If you have mounted the alignment slit:
•
Move the chamber up and down until the X-ray
beam passes through the alignment slit with
maximum intensity I
max
.
5. Carry out an
-scan and measure the beam
intensity.
Determine the
-offset of the maximum of the
intensity profile.
TIP: For
-
diffractometers, rotate detec-
tor around the centre axis of the goniometer.
For
-2
diffractometers, rotate the chamber around
the centre axis of the goniometer.
When starting with the
-alignment, do the
-scan
with ±3°. As the alignment gets better, reduce the
scan range.
6. Depending on the
-offset (
), rotate the
chamber as described in the instruction manual
for the diffractometer:
-offset negative (–) -> rotate clockwise
-offset positive (+) -> rotate anti-clockwise
7. Fix the chamber on the goniometer.
8. Set the goniometer back to
=
= 2
= 0 ° and
re-align the chamber height (z-position) as
described in step 4.
9. Repeat steps 5 – 8 until the offset
is < 0.05 °.
10.Measure a reference sample to check the align-
ment. Compare the measured peak position val-
ues with known standard values.
5.6 Checking the Instrument Condition
Before you start operation:
•
Make sure that HTK 1200N is installed correctly
and that no collisions between the sample
chamber and components of the diffractometer
can occur.
•
Make sure that the cooling-water hoses con-
nected to the inlet/outlet nozzles are protected
against unintentional disconnection.
•
Check whether all cables are correctly mounted
before switching on the CCU 1000
Combined Control Unit.
•
Check whether the foil on the X-ray windows of
the sample chamber is undamaged and clean.
•
Make sure a sample holder is mounted inside
the sample chamber.
NOTICE
Risk of Damage
•
Remove the alignment slit before starting a
measurement!
•
Do not heat the chamber when the alignment
slit is still mounted.
