Powder dictionary (pdCIF) version 1.0.1
Category PD_CALIB
Name:'_pd_calib_[pd]'
Definition:
This section defines the parameters used for the calibration of the instrument that are used directly or indirectly in the interpretation of this data set. The information in this section of the CIF should generally be written when the intensities are first measured, but from then on should remain unchanged. Loops may be used for calibration information that differs by detector channel. The _pd_calibration_ items, however, are never looped.Examples:
Example 1.
_pd_calib_std_external_block_id
QuartzPlate|D500#1234-987|B.Toby|91-15-09|14:02
_pd_calib_std_external_name
'Arkansas Stone quartz plate'
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Example 2 - 2\q~actual~ = 2\q~setting~ + arctan(
cos(P~1~) / {1/[P~0~ (CC - CH~0~ - P~2~ CC^2^)] -
sin(P~1~)} ). This allows for the calibration of 2\q
for a linear position-sensitive detector (PSD) where
the PSD has been set so that the 'centre channel'
(CH~0~) is located at 2\q~setting~ as a function of the
channel number (CC). In addition to CH~0~, variables
P~0~, P~1~ and P~2~ are calibration constants, where
P~0~ is the width of a PSD channel in degrees, P~1~ is
the angle of the PSD with respect to the perpendicular
and P~2~ is a quadratic term for nonlinearities in the
detector.
_pd_calibration_conversion_eqn
; 2\q~actual~ = 2\q~setting~ + arctan(
cos(P~1~)/{1/[P~0~ (CC - CH~0~ - P~2~ CC^2^)] - sin(P~1~)})
;
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Type: null
Category: category_overview
