Data items in the DIFFRN_STANDARDS category record details
about the set of standard reflections used to monitor intensity
stability during the measurement of diffraction intensities.
Note that these records describe properties common to the set of
standard reflections, not the standard reflections themselves.
_diffrn_standards.diffrn_id 's1'
_diffrn_standards.number 3
_diffrn_standards.interval_time 120
_diffrn_standards.decay_% 0