Dimensional Extreme Magnetic Neutron Diffractometer
DEMAND | HB-3A | HFIR
DEMAND runs with a large high-pixelated detector, that enables the efficient reciprocal space mapping, allowing the studying the novel structure and magnetic phases, and short-range order, even diffuse scattering. The instrument can run in the “Four-Circle mode” and “Two-axis mode” with easily switchable polarized and unpolarized neutron beam. The “Four-Circle mode” allows the full reciprocal space access, multiple scattering studies, high-resolution mapping the peak shape in 3D that can be used for detailed crystal screening, high pressure sciences, polarized neutron diffraction, electric field and stimulation, and other user-designed sample environment within the temperature range of 4 K-700 K. The “Two-Axis mode” is mostly for the experiments require the ultra-low temperature sample environment (0.04 K to 4 K) or/and cryomagnetic field (-6 to 6 T), in which, the large vertical detector coverage (-8o to 40o) ensures enough reciprocal space coverage out-of-scattering-plane. The polarized beam is available for both thermal neutrons of 1.5424 Å and cold neutrons of 1.541 Å with He-3 filter polarizer and S-bender supermirror polarizer, respectively. Two ways of data reduction are available, MantidWorkbench through https://analysis.sns.gov/ and ReTIA (Real-Time Image Analyzer).
Published articles present details the instrument’s capability and specification:
- B. C. Chakoumakos, et al., “Four-circle single-crystal neutron diffractometer at the High Flux Isotope Reactor", Journal of Applied Crystallography 44, 655-658 (2011).
- H.B. Cao, et al., "DEMAND, a Dimensional Extreme Magnetic Neutron Diffractometer at the High Flux Isotope Reactor", Crystals, 9, 1, 5 (2019).
- Y. Hao, et al., “Machine-learning-assisted automation of single-crystal neutron diffraction”, Journal of Applied Crystallography 56, 519-525 (2023).
For remote user experiments, please visit the User Guide to Remote Experiments webpage.
Shipping Addresses for Samples
For details information, please visit the ORNL User Facilities Sample Handling and Shipping page.
Non-activated samples coming to HFIR:
Recipient: IPTS XXXXX, HFIR user sample
Oak Ridge National Laboratory / HFIR Site
1 Bethel Valley Road
Bldg 7972 Room 100 [Special requirements (example: freezer or intert gas)]
Oak Ridge, TN 37830
HFIR Sample Management Desk phone number: 865-576-9030
Activated samples coming to HFIR:
Recipient: IPTS XXXXX, HFIR user sample [Replace the XXXX with your IPTS number]
Oak Ridge National Laboratory / HFIR Site
1 Bethel Valley Road
Bldg 7001 [Special requirements (example: freezer or intert gas)]
Oak Ridge, TN 37830
HFIR Sample Management Desk phone number: 865-576-9030
Users are encouraged to use a shipping provider who delivers directly to ORNL (ex: FedEx, UPS, DHL). These shipments are considered priorities and are processed through ORNL shipping facilities within 8-24 hours of delivery. Please be aware that the use of USPS may delay the processing of your shipment. due to a longer lead time for sorting.
NOTE: Replace the XXXX with your Integrated Proposal Tracking System (IPTS) number.
Software Downloads
Data is accessed and reduced remotely on the SNS analysis cluster using Mantidworkbench. A good tool to obtain an overview of your measured files is through ONCat.
The data reduction process has changed in 2021. Please refer to the following manuals for data reduction:
- MantidWorkbench - explains how to login to the SNS analysis cluster, start and describes MantidWorkbenchNightly
- ReTIA – Automated data reduction build in the instrument (in development).
- Graffiti – This program allows the user to browse through the scans (only .dat files) in the experiment. It also allows combining data sets, angle calculations, spurion checks, etc.
- FullProf, Jana, and Shelx are the major refinement packages for determination of nuclear and magnetic structures.
- Bilbao Crystallographic Server and SaraH – contains the user friendly structural and magnetic symmetry analysis tools.
Lecture Notes and Example Data
Please refer to the Lecture Notes page from the Magnetic Structure Determination from Neutron Diffraction Data Workshop 2014 for example data and relevant articles.
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