The peak1 command sets the value for the 1st reflection to be used in
the UB matrix calculation.
The syntax for the peak1 command is:
peak1 h k l s2 s1 sgl sgu ei ef
OR
peak1 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 first 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 available when the mode is set
to Define
scattering plane vectors and 1 reflection (shown in the first
image below) Define
2 non-colinear reflections (shown in the second image below).
In both cases, 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). In the second case (2 non-colinear
reflections), to add the input information as the first reflection, the
blue pull-down menu must be set to Reflection 1.
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 peak1 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.
