Data Collection
Use Snapshot to take a test exposure of
the crystal (remembering to collect the dark current
for at least the first snapshot). Snapshot will
automatically start up the Adxv
display software so you can view the exposure.
If necessary you can rotate the crystal using Manual
Control and take another snapshot.
Data collection proper is routinely carried out through the
Run(s) window.
Set the parameters for data collection in the Run(s) window.
Note that the starting Phi value for the run is not automatically
set to the current Phi value (as shown in the Status window).
If these differ the crystal will be rotated before the first image is
collected. Ensure that the distance for the run is the same as the current
distance displayed in the status window. If you wish to collect data
at a different distance move to the new distance using Manual
Control and reoptimise the beam before starting data
collection.
It is possible to collect data in time mode only at the moment.
In the Runs window the fields for 2-theta, kappa
and omega are redundant and should be left at 0.00. The dezingering
(De-Zngr) option is NOT recommended as problems with zingers should
be negligible at the usual exposure times used on the station (seconds to
1-2 minutes). Dezingering in these cases will provide no improvement in
data quality and only result in increased data collection times.
Most processing software throws out the zingers anyway ! A dark current
will automatically be collected at the start of each run and subtracted
from each of the images before they are seen by the User.
Start data collection by clicking on the Collect button.
When a run of data collection is complete another may be started by
setting parameters in the Run(s) window and clicking on
Collect. Runs may also be set up during data collection
ready to start at the end of the current run. Data may be examined and
processed on bl141alpha2 while data collection is still running
without affecting data collection.
Image Display Using the Adxv Software
Images once collected may be examined using the Adxv software on
bl142alpha1. This software is initialised with the command
adxv which produces the following three windows.
Adxv Load: In this window it is possible to choose a
directory, list the files within it and load an image.
Adxv Control: This window allows the user to alter the
viewing parameters of the image. For example, it allows parts of
the image to be magnified, the colour scheme of the image to be
altered and the contrast of the spots to be changed, all for
optimum viewing of the image. Clicking on File allows
image files to be loaded or saved and the window to be exited.
The View option enables a histogram of chosen peaks, the
image header and statistics to be examined.The Edit option
allows the beam center to be altered, the resultion rings to be switched on/off
and background subtraction to be carried out.
Adxv: This final window displays the image. Clicking on the
left/right hand buttons on the mouse while over this window
enables areas of the image to be magnified and viewed in various
ways and rows of spots to be chosen for lattice parameter
determination. The resolution of a particular position may be
obtained by placing the mouse at that position, the resolution and
intensity are then shown in the upper left corner of the window.
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switch,
allows remote control of the detector and phi axis. Open and close the
shutter by clicking Shutter on the menu bar.
