THERMAL NEUTRON INSTRUMENTATION

The thermal neutron instruments at the NCNR are housed in the confinement building.One cold neutron instrument (MACS) is also located in this building.

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They include

• BT1 - high resolution powder diffractometer*
• BT2 - neutron imaging facility*
• BT4 - filter analyzer spectrometer
• BT4 - triple axis spectrometer
• BT5 - ultra-small angle neutron scattering (USANS) diffractometer*
• BT7 - double-focusing triple-axis spectrometer*
• BT8 - residual stress diffractometer
• BT9 - MACS - ultra high efficiency cold neutron spectrometer*
• facilities for neutron activation analysis

*accessible through user proposals. These and the other instruments are also available for collaborative projects with NIST staff.

The neutron scattering instruments in the confinement building have been replaced or modernized over many years. Improvements have been made with regard to safety and flexibility of operation, involving the installation of new monochromator drums which provide both a safer working environment and an improved signal to noise ratio. Beam apertures are remotely adjustable, and neutron-sensitive video cameras are used for sample positioning and alignment. The filter analyzer option on BT4 has been supplanted by a dedicated filter-analyzer instrument, in which the solid angle subtended by the detectors, and hence the useful signal, has increased by more than an order of magnitude. The greater sensitivity permits many new possibilities in spectroscopy in the 10-100 meV range, with resolutions of 1-2 meV. The triple-axis spectrometers allow the routine use of double- (i.e., both vertically- and horizontally-) focusing monochromator and analyzer assemblies, which can enhance signal by an order of magnitude in many types of experiments.

Thermal neutrons are employed at the NCNR for a wide variety of applications other than neutron scattering, such as maintaining radiation and dosimetry standards, development of radiation detectors, and neutron activation analysis studies for the Food and Drug Administration, the Federal Bureau of Investigation, and a number of other government agencies, industries, and universities.

Last modified 24-July-2013 by website owner: NCNR (attn: )