Soller collimators for small angle neutron scattering

Conference · Fri Sep 30 04:00:00 EDT 1988

OSTI ID:6471604

Crawford, R K; Epperson, J E; Thiyagarajan, P

Small angle diffractometers at pulsed sources need to have fairly short flight paths if they are to make use of the long-wavelength portion of the spectrum without encountering problems from frame overlap or sacrificing intensity with band-limiting or pulse-removing choppers. With such short flight paths, achieving the necessary angular collimation in the incident beam while utilizing the full source size (/approximately/10 cm diameter) and a reasonable sample size (/approximately/1 cm diameter) requires the use of converging multiple-aperture collimation. If the collimation channels are all focused to the same point on the detector then the large sample size will not affect Q/sub min/ or the Q-resolution, even if the sample-to-detector distance is short. The Small Angle Diffractometer (SAD) at IPNS uses crossed converging soller collimators to provide focusing multiple-aperture collimation having /approximately/400 converging beam channels with essentially no ''dead'' space between them. This entire collimator system occupies a distance of only /approximately/60 cm along the incident flight path, while providing angular collimation of 0.003 radians FWHM. The dimensions for the SAD upstream collimator are L/sub c/ = 32.8 cm, d/sub 1/ = 0.974 mm, d/sub 2/ = 0.851 mm, while for the SAD downstream collimator L/sub c/ = 25.0 cm, d/sub 1/ - 0.844 mm, d/sub 2/ = 0.750 mm. Each of these collimators has 20 blades defining 21 horizontal or vertical channels. 4 refs., 6 figs.

• Research Organization: Argonne National Lab., IL (USA)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6471604
• Report Number(s): CONF-8810182-17; ON: DE89007379
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
430301* -- Particle Accelerators-- Ion Sources
ACCELERATORS
BEAMS
COHERENT SCATTERING
COLLIMATORS
CYCLIC ACCELERATORS
DIFFRACTION
DIFFRACTOMETERS
FOCUSING
IPNS-I SYNCHROTRON
MEASURING INSTRUMENTS
MONTE CARLO METHOD
NEUTRON BEAMS
NEUTRON DIFFRACTION
NEUTRON DIFFRACTOMETERS
NEUTRON SOURCE FACILITIES
NEUTRON SOURCES
NUCLEON BEAMS
OPTICAL PROPERTIES
PARTICLE BEAMS
PARTICLE SOURCES
PHYSICAL PROPERTIES
RADIATION SOURCES
REFLECTIVITY
SCATTERING
SMALL ANGLE SCATTERING
SURFACE PROPERTIES
SYNCHROTRONS