The peak2 command sets the value for the 1st reflection to be used in
the UB matrix calculation.
The syntax for the peak2 command is:
peak2 h k l s2 s1 sgl sgu ei ef
OR
peak2 h k l
The first syntax specifies the motor positions explicitly while with
the second syntax, the current motor positions are used.
The position and indices for the second reflection can also be set from
the GUI by selecting the UB Matrix
tab from the Sample top-level
tab. The first peak information is only available
when the mode is set to Define 2
non-colinear reflections (shown in the image below). The
peak can be added either using the current motor positions or by
specifying the positions explicitly (as controlled by the blue pull-down
menu). To add the input information as the second reflection, the
blue pull-down menu must be set to Reflection 2.
There is also a green button at the bottom of the tab which
allows you to swap
the information for reflections 1 and 2. To calculate the
UB matrix hit the blue Calculate UB Matrix Update Orientation
Information button.
NOTE: the orientation information is easier to modify from the GUI than
from the command-line as it allows the user to preview the orientation
information prior to accepting the changes. The peak2 command
should only be executed from the command-line by experienced users as it
could yield unexpected results. For detailed information about
entering orientation information from the GUI see the How to
align a single crystal guide.
