Data Item _diffrn_radiation.div_x_y_source

General

Item name
_diffrn_radiation.div_x_y_source
Category name
diffrn_radiation
Attribute name
div_x_y_source
Required in PDB entries
no
Used in currrent PDB entries
No

Item Description

Beam crossfire correlation in degrees squared between the crossfire laboratory X-axis component and the crossfire laboratory Y-axis component (see AXIS category). This is a characteristic of the X-ray beam as it illuminates the sample (or specimen) after all monochromation and collimation. This is the mean of the products of the deviations of the direction of each photon in XZ plane times the deviations of the direction of the same photon in the YZ plane around the mean source beam direction. This will be zero for uncorrelated crossfire. Note that for some synchrotrons, this value is specified in milliradians squared, in which case a conversion is needed. To convert a value in milliradians squared to a value in degrees squared, multiply by 0.1802 and divide by \p2.

Data Type

Data type code
float
Data type detail
float item types are the subset of numbers that are the floating point numbers.
Primitive data type code
numb
Regular expression
-?(([0-9]+)[.]?|([0-9]*[.][0-9]+))([(][0-9]+[)])?([eE][+-]?[0-9]+)?
Default value
0.0
Units
degrees_squared