A TWO-CRYSTAL NEUTRON SPECTROMETER

Journal Article · Tue Jan 01 04:00:00 EST 1957 · Kristallografiya (U.S.S.R.) For English translation see Sov. Phys. - Crystallogr. (Engl. Transl.)

OSTI ID:4339957

Bykov, V N; Vinogradov, S I; Levdik, V A; Golovkin, V S

The Soviet atomic pile used for power generation will provide a flux of 2 x 10/sup 13/ neutrons/sec cm/sup 2/ which can be used for diffraction. A 5-m steel tube emerges through the shielding and provides a naturally collimated beam of 24' divergence. The integrated thermal neutron flux falling on the monochromater is 10/sup 7/ neutrons/cm/sup 2/ sec. The monochromatization is by reflection from the 200 plane of a lead crystal 135 x 55 x 22 mm. The hall width of the reflected beam is usually 37' correspending to an energy uncertainty of 9%. There may also be 2.5% diffusely scattered neutrons. After monochromatization the flux is about 10/sup 4/ neutrons/cm/sup 2/ sec. The lead crystal which is behind 80 cm of concrete can be moved in any required direction to direct the beam down the final collimator which is made of paraffin and boron carbide. The apparatus is more properly called a diffractometer as the reflected intensities are measured on a boron trifluoride counter and recorded as in x-ray diffractometry. The specimen counter distance is 20 to 100 cm. Angles can be measured on a 110 cm diameter circle to 2'. A specimen to counter rotation ratio of 1: 2 is provided. The counter has a diameter of 2 cm and a length of 27 cm; it is filled to 700 mm Hg wth BF/sub 3/ enriched in B/sup 10/. A test crystal of KBr of dimensions 6 x 6 x 8 mm gave peak counts of 3100/min (200 reflection) wth a uniform background of about 100/min and very satisfactory resolution. An iron rod (8 mm diam) which was polycrystalline, gave peaks of 200/min with a background of 200/min. (TCO)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-12-011166
• OSTI ID: 4339957
• Journal Information: Kristallografiya (U.S.S.R.) For English translation see Sov. Phys. - Crystallogr. (Engl. Transl.), Journal Name: Kristallografiya (U.S.S.R.) For English translation see Sov. Phys. - Crystallogr. (Engl. Transl.) Vol. Vol: 2; ISSN KRISA
• Country of Publication: Country unknown/Code not available
• Language: Russian

Related Subjects

BACKGROUND
BORON 10
BORON CARBIDES
BORON FLUORIDES
COUNTERS
CRYSTALS
DIFFRACTION
ENERGY
ENRICHMENT
IRON
LATTICES
LEAD
LIFETIME
MEASURED VALUES
MONOCHROMATORS
MONOCRYSTALS
NEUTRON BEAMS
NEUTRON FLUX
NEUTRON SPECTROMETERS
PARAFFIN
PHYSICS
PLANNING
POTASSIUM BROMIDES
REACTORS
RECORDING SYSTEMS
REFLECTION
RESOLUTION
RODS
SCATTERING
SHIELDING
STANDARDS
TESTING
THERMAL NEUTRONS
WIDTH