Abstract
A fine resolution chopper spectrometer (SEQUOIA) recently received first neutrons
at the SNS. The commissioning phase of the instrument is underway. SEQUOIA is designed
to utilize neutrons of an incident energy (Ei) between 10-2000 meV. A monochromatic beam
is provided on a sample, 20 m from the decoupled ambient temperature H2O moderator, by
filtering the white beam with a Fermi chopper located 18 m from the source. After interacting
with the sample, neutrons are detected by an array of 3He linear position sensitive tubes located
on a vertical cylinder with a radius of 5.5 m. This contribution presents current results from the
commissioning experiments and compares SEQUOIA’s actual and predicted performance. These
commissioning experiments include characterization of the beam by monitors, determination of
the chopper phase offsets, and runs with V and C4H2I2S. The predicted performance is provided
by analytical calculations and Monte Carlo simulations.
