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Title: Design of a high-flux backscattering spectrometer for ultra-high resolution inelastic neutron measurements

Conference ·
OSTI ID:225250
;  [1];  [2]
  1. National Inst. of Standards and Technology, Gaithersburg, MD (United States). Reactor Radiation Div.
  2. Univ. of Maryland, College Park, MD (United States). Dept. of Materials and Nuclear Engineering

The authors discuss the design of a new backscattering spectrometer to be installed at the Cold Neutron Research Facility at the National Institute of Standards and Technology. Si (111) crystals cover both monochromator and analyzer which are spherically bent to a radius of curvature of {approximately} 2 m to focus the incident and scattered neutron beams. The bending increases the intrinsic lattice gradient of Si beyond its Darwin limit, resulting in an energy resolution of {approximately} 0.75 {micro}eV FWHM. The monochromator is Doppler-driven, allowing users access to a dynamic range of {+-} 60 {micro}eV. The elastic Q-range covers 0.15 to 1.8 {angstrom}{sup {minus}1}. The most novel aspect of this design lies in the incorporation of a phase-space-transform chopper. This device rotates at 4,700 rpm while neutrons are Bragg-diffracted from sets of pyrolytic graphite crystals affixed to its periphery. The process enhances the neutron flux at the backscattering energy of 2.08 meV, but at the expense of a larger horizontal divergence. Computer simulations indicate a result flux increase of order 3 should be obtained.

OSTI ID:
225250
Report Number(s):
CONF-941144-; ISBN 1-55899-278-2; TRN: IM9621%%180
Resource Relation:
Conference: Fall meeting of the Materials Research Society (MRS), Boston, MA (United States), 28 Nov - 9 Dec 1994; Other Information: PBD: 1995; Related Information: Is Part Of Neutron scattering in materials science 2; Neumann, D.A. [ed.] [National Inst. of Standards and Technology, Gaithersburg, MD (United States)]; Russell, T.P. [ed.] [IBM Almaden Research Center, San Jose, CA (United States)]; Wuensch, B.J. [ed.] [Massachusetts Inst. of Tech., Cambridge, MA (United States)]; PB: 813 p.; Materials Research Society symposium proceedings, Volume 376
Country of Publication:
United States
Language:
English