Cold Neutron Triple-Axis Spectrometer
Mission Statement
The US/Japan Cold Neutron Triple-Axis (CTAX) Spectrometer is a collaboration of the Neutron Sciences Directorate at Oak Ridge National Laboratory and the Institute of Solid State Physics at the University of Tokyo, as part of the US-Japan Cooperative Program on Neutron Scattering. It is a cold neutron spectrometer to study static and dynamic properties of spin and lattice in materials.
Instrument Description
Of the four triple-axis spectrometers installed at HFIR, CTAX is a conventional cold neutron triple-axis spectrometer with variable incident energy and sample-analyzer distances. The cold guide 4 bender and guide hall shielding reduce background levels at CTAX, and the 15-cm-tall guide profile is well exploited by CTAX′s vertically focusing PG(002) monochromator. To enhance accommodation of strong magnetic fields at the sample position and simplify future polarization analysis, the amount of ferromagnetic material has been minimized in the construction of this instrument.
Applications
CTAX is suited for studies of nuclear and magnetic structures, quasi-elastic scattering, and lattice and magnetic dynamics in a variety of materials, including superconductors, transition metal oxides, multiferroics, thermoelectric materials, and low-dimensional quantum magnets. It enables better analysis of low-energy excitations in materials with high signal-to-noise ratio. CTAX can accommodate a wide variety of sample environments, including high temperature furnaces (< 1770 K), ultra-low temperature cryostats (> 0.05K), vertical-field cryomagnets (< 8T), horizontal-field cryomagnet (< 6 T) and pressure cells (< 2 GPa). The materials best suited for study on CTAX facilitate data transmission in computers; impact the capacity of computer memory (hard disk); and improve the efficiency of electric devices.
Specifications
| Incident energy range | 2 – 18 meV |
| Final energy range | ≥3.0meV |
| Sample scattering angles | -15° ≤ 2Θs ≤ 115°, with additional restrictions depending on Ei |
| Collimation before mono-chromator | Guide dependent (40′ at 2 meV, 20′ at 18 meV) |
| Collimation after mono-chromator | 10′, 20′, 40′, 80′ |
CTAX Instrument Team
Please select link below to email the instrument team. Be sure to include your name and email address.
Information for CTAX Users
- Shipping address for samples: Please visit the ORNL User Facilities Sample Handling and Shipping page for the correct address. Do not ship samples directly to the CG-4C instrument team members.
- Access to CG-4C data: Data files are accessible at the instrument using the Spectrometer Instrument Control Environment (SPICE) data acquisition system. Data may be accessed remotely from a secure server using the HFIR Graffiti software.
- Sample Environments: CG-4C can accommodate a wide variety of sample environments. For more information, please visit the following page: https://neutrons.ornl.gov/sample. Once you are notified of an approved proposal, please update your impossible dates in IPTS as soon as possible to ensure that they are accommodated in our instrument schedule. Note that there will be limited scheduling flexibility for experiments requiring sample environments other than closed cycle refrigerators.
- Neutron alignment station (CG-1B): If you need to align a single crystal with neutrons before your CG-4C experiment begins, please email the CG-4C instrument team well in advance so alignment time can be reserved for you on CG-1B. Note that we have a first come, first served scheduling system for this instrument. Also, let the instrument team know if you are experienced with sample alignments or if you will require significant assistance.
- Links Related to Neutron Scattering and Crystallography
a. Neutron scattering lengths and cross sections (http://www.ncnr.nist.gov/resources/n-lengths/index.html)
b. Calculate absorption, basic activation calculation (http://www.ncnr.nist.gov/resources/activation/)
c. Inorganic Crystallographic Structure Database (ICSD) (https://icsd.fiz-karlsruhe.de/search/basic.xhtml) - User publications:
a. As a condition for performing nonproprietary research, the US Department of Energy requires users to publish results from their research. Authorship of publications based on research from these facilities should reflect the normal considerations of recognizing collaborations. It is also important to take into account the considerable efforts of the instrument scientists in their role of designing, constructing, and/or operating the instrument and related facilities. Results are typically published in peer-reviewed journals, proceedings, or presentations at technical conferences. Proprietary users are not required to publish.
b. Credit line: The CG-4C Cold Neutron Triple Axis Spectrometer should be acknowledged with this required statement:
This research [or, A portion of this research] used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory
c. Publication Record: Please submit publications, thesis, patents, etc., to PuSH (Publications of SNS and HFIR) to assist us in recording your contribution. Both the credit statement and links to PuSH are on the Neutron Sciences Publications website.
The scientific communities that use the CG-4C instrument include condensed matter physics and materials science. Typical applications of this instrument include studies of nuclear and magnetic structures, quasi-elastic scattering, and lattice and magnetic dynamics in a variety of materials, including superconductors, transition metal oxides, multiferroics, thermoelectric materials, and low-dimensional quantum magnets. An 11 T vertical, asymmetric field cryomagnet with a 3He insert option is dedicated to CG-4C for studies requiring a magnetic field.
Nuclear structure studies:
Determination of lattice distortion and phase transitions.
Example:
- Hong T., Zhu L. Y., Ke X., Garlea V. O., Qiu Y., Nambu Y., Yoshizawa H., Zhu M., Granroth G. E., Savici A. T., Gai Z., Zhou H. D., “Structural and magnetic properties in the quantum S=1/2 dimer system Ba3(Cr1-xVx)2O8 with site disorder“, Physical Review B 87, 144427 (2013).
Magnetic structure studies:
Magnetic propagation vector determination and order parameter measurement as a function of temperature or applied magnetic field.
Example:
- Taniguchi T., Kadowaki H., Takatsu H., Fak B., Ollivier J., Yamazaki T., Sato T. J., Yoshizawa H., Shimura Y., Sakakibara T., Hong T., Goto K., Yaraskavitch L. R., Kycia J. B., “Long-range order and spin-liquid states of polycrystalline Tb2+xTi2-xO7+y“, Physical Review B 87, 060408 (2013).
- MacDougall G. J., Garlea V. O., Aczel A. A., Zhou H. D., Nagler S. E., “Magnetic order and ice rules in the multiferroic spinel FeV2O4“, Physical Review B 86, 060414 (2012).
Phonon excitations:
Measurement of collective, low-energy lattice dynamics, including phonon lifetimes.
Example:
- Ma J., Delaire O., May A. F., Carlton C. E., McGuire M. A., VanBebber L. H., Abernathy D. L., Ehlers G., Hong T., Huq A., Tian W., Keppens V. M., Shao-Horn Y., Sales B. C., “Glass-like phonon scattering from a spontaneous nanostructure in AgSbTe2“, Nature Nanotechnology 8, 445-451 (2013).
Magnetic excitations:
Measurement of collective, low-energy spin dynamics.
Examples:
- Matsuda M., Fishman R. S., Hong T., Lee C. H., Ushiyama T., Yanagisawa Y., Tomioka Y., Ito T., “Magnetic dispersion and anisotropy in multiferroic BiFeO3“, Physical Review Letters 109, 067205 (2012).
- Wang C. H., Lumsden M. D., Fishman R. S., Ehlers G., Hong T., Tian W., Cao H., Podlesnyak A., Dunmars C., Schlueter J. A., Manson J. L., Christianson A. D., “Magnetic properties of the S=1/2 quasisquare lattice antiferromagnet CuF2(H2O)2(pyz) (pyz = pyrazine) investigated by neutron scattering“, Physical Review B 86, 064439 (2012).
- Nakajima T., Mitsuda S., Haraldsen J. T., Fishman R. S., Hong T., Terada N., Uwatoko Y., “Magnetic interactions in the multiferroic phase of CuFe1-xGaxO2 (x = 0.035) refined by inelastic neutron scattering with uniaxial-pressure control of domain structure“, Physical Review B 85, 144405 (2012).