Beamline performance simulations for the fundamental neutron physics beamline at the spallation neutron source

• Published in: Journal of research of the National Institute of Standards and Technology Vol. 110; no. 3; pp. 161 - 168
• Main Authors: Huffman, P.R., Greene, G.L., Allen, R.R., Cianciolo, V., Huerto, R.R., Koehler, P., Desai, D., Mahurin, R., Yue, A., Palmquist, G.R., Snow, W.M.
• Format: Journal Article
• Language: English
• Published: United States National Institute of Standards and Technology 01.05.2005; Superintendent of Documents; National Institute of Standards (NIST); [Gaithersburg, MD] : U.S. Dept. of Commerce, National Institute of Standards and Technology
• Subjects: Instruments & Instrumentation; McStas; Monte Carlo simulation; neutron optics; neutron sources; Neutrons; Nuclear physics; Nuclear reactors; Optics; Optimization; OTHER INSTRUMENTATION; Particle physics; Physics; Superfluidity; neutron optics; neutron sources; McStas
• ISSN: 1044-677X; 2165-7254
• DOI: 10.6028/jres.110.018

Monte Carlo simulations are being performed to design and characterize the neutron optics components for the two fundamental neutron physics beamlines at the Spallation Neutron Source. Optimization of the cold beamline includes characterization of the guides and benders, the neutron transmission through the 0.89 nm monochromator, and the expected performance of the four time-of-flight choppers. The locations and opening angles of the choppers have been studied using a simple spreadsheet-based analysis that was developed for other SNS chopper instruments. The spreadsheet parameters are then optimized using Monte Carlo techniques to obtain the results presented in this paper. Optimization of the 0.89 nm beamline includes characterizing the double crystal monochromator and the downstream guides. The simulations continue to be refined as components are ordered and their exact size and performance specifications are determined.