title: Electrostatic levitation facility optimized for neutron diffraction studies of high temperature liquids at a spallation neutron source.
abstract: Neutron diffraction studies of metallic liquids provide valuable information about inherent topological and chemical ordering on multiple length scales as well as insight into dynamical processes at the level of a few atoms. However, there exist very few facilities in the world that allow such studies to be made of reactive metallic liquids in a containerless environment, and these are designed for use at reactor-based neutron sources. We present an electrostatic levitation facility, NESL (for Neutron ElectroStatic Levitator), which takes advantage of the enhanced capabilities and increased neutron flux available at spallation neutron sources (SNSs). NESL enables high quality elastic and inelastic neutron scattering experiments to be made of reactive metallic and other liquids in the equilibrium and supercooled temperature regime. The apparatus is comprised of a high vacuum chamber, external and internal neutron collimation optics, and a sample exchange mechanism that allows up to 30 samples to be processed between chamber openings. Two heating lasers allow excellent sample temperature homogeneity, even for samples approaching 500 mg, and an automated temperature control system allows isothermal measurements to be conducted for times approaching 2 h in the liquid state, with variations in the average sample temperature of less than 0.5%. To demonstrate the capabilities of the facility for elastic scattering studies of liquids, a high quality total structure factor for Zr64Ni36 measured slightly above the liquidus temperature is presented from experiments conducted on the nanoscale-ordered materials diffractometer (NOMAD) beam line at the SNS after only 30 min of acquisition time for a small sample (∼100 mg).
authors.affiliation: Department of Physics, North Central College, Naperville, Illinois 60540, USA.
authors.forename: N A
authors.initials: NA
authors.lastname: Mauro
authors.affiliation: Instrument and Source Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Vogt
authors.affiliation: Mechanical Engineering and Materials Science, Washington University, St. Louis, Missouri 63130, USA.
authors.forename: K S
authors.initials: KS
authors.lastname: Derendorf
authors.affiliation: Department of Physics and Institute of Materials Science and Engineering, Washington University, 1 Brookings Drive, St. Louis, Missouri 63130, USA.
authors.forename: M L
authors.initials: ML
authors.lastname: Johnson
authors.affiliation: Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: G E
authors.initials: GE
authors.lastname: Rustan
authors.affiliation: Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: D G
authors.initials: DG
authors.lastname: Quirinale
authors.affiliation: Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: A
authors.initials: A
authors.lastname: Kreyssig
authors.affiliation: Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Lokshin
authors.affiliation: Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Neuefeind
authors.affiliation: Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Ke
authors.initials: K
authors.lastname: An
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Ave., Kowloon, Hong Kong.
authors.forename: Xun-Li
authors.initials: XL
authors.lastname: Wang
authors.affiliation: Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: A I
authors.initials: AI
authors.lastname: Goldman
authors.affiliation: Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA.
authors.forename: T
authors.initials: T
authors.lastname: Egami
authors.affiliation: Department of Physics and Institute of Materials Science and Engineering, Washington University, 1 Brookings Drive, St. Louis, Missouri 63130, USA.
authors.forename: K F
authors.initials: KF
authors.lastname: Kelton