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COLD NEUTRON INSTRUMENTS


Plan View of the NCNR Guide Hall
 
Plan view of Guide Hall
Neutron Spin Echo Spectrometer Neutron Spin Echo Spectrometer Spin Polarized Triple Axis Spin Polarized Triple Axis 30 Meter SANS (NGB) 30 Meter SANS (NGB) 30 Meter SANS (NGB) 30 Meter SANS (NG7) 30 Meter SANS (NG7) nSoft 10m SANS Instrument High Flux Backscattering Spectrometer High Flux Backscattering Spectrometer Disk Chopper Time of Flight Spectrometer Disk Chopper Time of Flight Spectrometer Prompt Gamma Activation Analysis Station Horizontal Geometry Reflectometer MAGIk reflectometer PBR Polarized Beam Reflectometer Neutron Interferometer Neutron Interferometer Neutron Interferometer Fundamental Physics Station Fundamental Physics Station aCORN Physics Experiment aCORN Physics Experiment Cold Neutron Depth Profiling Instrument and Detector Development Station
Twelve neutron guides transport neutrons emerging from the primary cold source through distances of tens of meters to the stations in the guide hall. Another cold neutron beamline terminates inside the confinement building, emanating from a small dedicated liquid hydrogen moderator that provides 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 nearly flat interior surfaces of long metal-coated glass tubes. 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 coatings in the oldest guides (NG-3,5,6,7) is dictated by their relatively large values of theta-c, an advantage for producing the highest possible neutron flux at the experimental stations (listed below). Three of the older 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. The newest guides (NG-A, B, C, D) also employ multiayer coatings and more complex construction (details), providing additional gains.

Instruments in the guide hall:

Operating in the confinment building:

Last modified 07-May-2014 by website owner: NCNR (attn: Przemek Klosowski)