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COLD NEUTRON INSTRUMENTS

Plan View of the NCNR Guide Hall
 
Plan view of Guide Hall
ANDR bioscience reflectometer Vertical Geometry Reflectometer 8 Meter SANS High Flux Backscattering Spectrometer Disk Chopper Time of Flight Spectrometer Spin Polarized Triple Axis Neutron Spin Echo Spectrometer Fermi Chopper Time of Flight Spectrometer Horizontal Geometry Reflectometer Prompt Gamma Activation Analysis Station 30 Meter SANS (NG7) 30 Meter SANS (NG3) Neutron Interferometer Fundamental Physics Station
Seven neutron guides transport neutrons emerging from the cold source through distances of tens of meters to the stations in the guide hall. An eighth large neutron beam terminates inside the confinement building, and will provide neutrons for an advanced multi-axis crystal spectrometer (MACS). The neutron guides work by a simple principle, i.e., total external reflection of neutrons from the flat surfaces of a rectangular tube formed by Ni-58-coated glass surfaces. Neutrons which graze the surfaces within a small angle (theta less than theta-c = 1.18 deg. for 10 A neutrons incident on Ni-58) are totally reflected because the index of refraction for neutrons is slightly less than one. The use of Ni-58 is dictated by its relatively large values of theta-c, an advantage for producing the highest possible neutron flux at the experimental stations (listed below). The three newest guides (NG-1,2,4) have multilayer coatings on top and bottom surfaces which provide an additional factor of 1.7 in available neutron intensity.

Operational instruments:

Under construction:

Last modified 19-January-2007