BT-7 Double Focusing Triple-Axis Spectrometer

Contact:    Ying Chen, (301) 975-6442, Ying.Chen@nist.gov

Jeff Lynn, (301)975-6246, Jeff.Lynn@nist.gov

Current Schedule Source Schedule Detailed Specifications Design Features Polarized Beam Operation ScanMapper Quickstart guide Recent Thermal Triple Axis Publications Access to the NCNR Facilities Monetary Assistance Programs Sample Environment DAVE (Data Analysis Software) ICE Software Proposal/BeamTime Form Photos of BT-7

As part of the modernization of the thermal neutron spectrometers, a new state-of-the-art thermal neutron instrument is being commissioned at the BT-7 thermal beam port.  There is a choice of collimations in the reactor beam that bring neutrons onto a choice of PG(002) or Cu(220)  20×20 cm²double focusing monochromators.  The sample stage incorporates a independent magnet axis in addition to the usual motorized sample orientation and rotation angles.  The analyzer and detector system is housed in a single unit on air pads.  The new analyzer has now been installed and provides horizontal focusing capability, or it can use a flat crystal array coupled with a position-sensitive detector to allow the simultaneous collection of data over a range of (Q,E), or it can use a choice of different conventional collimators, all remotely and under computer control.  The analyzer/detector system is designed to be self-contained so that it can be easily interchanged with a different style of analyzer as new systems are developed.  Guide fields are incorporated throughout the instrument to enable polarized beam operation.  A similar spectrometer is being developed for the BT-1 beam port.

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