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HIGH-RESOLUTION NEUTRON
POWDER DIFFRACTOMETER BT-1

The BT-1 high-resolution neutron powder diffractometer is used to to obtain neutron powder diffraction data for crystallographic analysis by the Rietveld method or other characterization purposes. It is a 32 detector instrument that can be used with three different monochromators and two different incident Soller collimators, allowing the instrument response to be tailored to the needs of the experiment. The instrument can be used with furnaces, refrigerators and cryostats so that data may be collected at temperatures from 0.3 to 2000 K, and with magnet fields. For room-temperature data collection, a six-position sample changer is available.

Choice of Monochromator and Collimator

The choice of three focusing monochromators, Ge(311), Cu(311), and Ge(733), and either a 60', 15' or a 7' in-pile Soller collimator allows optimization of the instrument's resolution minimum versus relative diffraction intensities. All monochromators give data up to 165 degrees in 2 theta range.

Resolution in Each Operational Mode

The shape of the BT-1 instrument response function for the six different operational modes can be viewed in angular units or Q-1) and relative intensities are tablulated in BT-1 Specifications. (Note that these curves show peak widths observed from a reference sample.)

Ideal Sample Size

The ideal sample size for BT-1 is 10 cm3 (typically 5-15 g) of material, although data have been collected on samples as small as 200 mg.




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