Project Title: Neutron Velocity Selector Test Base and Cover
Project Summary: NIST consists of a number of beamlines allowing scientists and engineers to do cutting edge neutron research. Each beamline consists of multiple components, one of which is the Neutron Velocity Selector (NVS). The NVS is designed to efficiently transmit the primary wavelength neutrons while suppressing second order, third order, etc., neutrons so that the incident beam from the PG or Cu crystals onto the sample is monochromatic. The NVS spin at incredibly fast speeds and could pose a danger to the machine operators if they were to break apart during the testing phase. Working with NIST, our team will design a permanently mounted base with an attached protective cover to house all models of NVS during the testing phase and ensure the safety of all test participants in the event of a worst-case scenario.
Neutrons that are faster or slower than those “allowed” for a given selector rotation speed are absorbed on the blade surfaces while traveling through the selector. The number of blades and their spacing determine the spread of velocities (wavelengths) around the mean velocity achieved. This “wavelength spread” is typically of the order of 9%. Lowering the speed of the velocity selector favours the passage of slower
neutrons (here shown for 20Å wavelength, marked in blue) The velocity selector thus acts as a monochromator.
Source: Institut Laue Langevin
