Design and operation of the wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source

Journal Article · Sun Jan 01 00:00:00 EST 2012 · Reviews of Scientific Instruments

DOI:https://doi.org/10.1063/1.3680104· OSTI ID:1036169

Abernathy, Douglas L ^[1]; Stone, Matthew B ^[1]; Loguillo, Mark ^[1]; Lucas, Matthew ^[2]; Delaire, Olivier A ^[1]; Tang, Xiaoli ^[3]; Lin, J. Y. Y. ^[3]; Fultz, B. ^[3]

---

1. ORNL
2. United States Air Force Research Laboratory, Wright-Patterson Air Force Base
3. California Institute of Technology, Pasadena

The wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source (SNS) is optimized to provide a high neutron flux at the sample position with a large solid angle of detector coverage. The instrument incorporates modern neutron instrumentation, such as an elliptically-focused neutron guide, high speed magnetic bearing choppers and a massive array of 3He linear position sensitive detectors. Novel features of the spectrometer include the use of a large gate valve between the sample and detector vacuum chambers and the placement of the detectors within the vacuum, both of which provide a window-free final flight path to minimize background scattering while allowing rapid changing of the sample and sample environment equipment. ARCS views the SNS decoupled ambient temperature water moderator, using neutrons with incident energy typically in the range from 15 to 1500 meV. This range, coupled with the large detector coverage, allows a wide variety of studies of excitations in condensed matter, such as lattice dynamics and magnetism, in both powder and single-crystal samples. Comparisons of early results to both analytical and Monte Carlo simulation of the instrument performance demonstrate that the instrument is operating as expected and its neutronic performance is understood. ARCS is currently in the SNS user program, and continues to improve its scientific productivity by incorporating new instrumentation to increase the range of science covered and improve its effectiveness in data collection.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1036169
• Journal Information: Reviews of Scientific Instruments, Vol. 83, Issue 1; ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

neutron instruments
time-of-flight
direct geometry