MLZ is a cooperation between:

Technische Universität München> Technische Universität MünchenHelmholtz-Zentrum Hereon> Helmholtz-Zentrum Hereon
Forschungszentrum Jülich> Forschungszentrum Jülich

MLZ is a member of:

LENS> LENSERF-AISBL> ERF-AISBL

MLZ on social media:

Logo

MLZ (eng)

Lichtenbergstr.1
85748 Garching

TRISP

Three axes spin echo spectrometer

TRISP TRISP

TRISP is a high-resolution neutron spectrometer combining the three axes and neutron resonance spin echo (NRSE) techniques. The design of TRISP is optimised for the study of intrinsic linewidths of elementary excitations (phonons, magnons) with an energy resolution in the µeV region over a broad range of momentum and energy transfers. Compared to conventional three axes spectro­meters (TAS), this corresponds to an improvement of the energy resolution of one to two orders of magnitude.

TRISP also incorporates the Larmor diffraction (LD) technique, which allows to measure lattice spacings with a relative resolution Δd/d = 1.5·10-6, i.e. one to two orders of magnitude better than conventional neutron or X-ray diffraction. Absolute d-values can be determined by calibrating the instrument against an Si standard. The main applications of LD include thermal expansion under pressure and low or high temperature, and distributions of lattice constants (second order stresses). LD thus is unique in a parameter region, where standard methods such as dilatometry fail.

Typical Applications
  • Measurement of the intrinsic linewidths of phonons
  • Measurement of the instrinsic linewidths spin excitations
  • Larmor diffraction is used to determine thermal expansion and second order stresses under pressure and at low or high temperature
Sample Environment

Besides the standard sample environment a dedicated dilution cryostat with a base temperature of 6 mK is available.

Technical Data
Primary beam
  • thermal beam tube SR-5b
    • polarising supermirror bender
    • 1.3 Å-1 < ki < 7.0 Å-1
  • Velocity selector
    • Astrium type, as higher order wavelengths filter
Monochromator
  • PG(002) or (004)
    • variable focussing horizontal and vertical
Analyzer
  • PG(002)
    • variable horizontal focussing
  • Heusler (111) (polarised neutrons)
    • variable horizontal focussing
Spin echo
  • Resonance spin echo, enclosed by mu-metal magnetic screen.

Instrument Scientists

Dr. Thomas Keller
Phone: +49 (0)89 289-12164
E-Mail: thomas.keller@fkf.mpg.de

Prof. Dr. Bernhard Keimer
Phone: +49 (0)711 689-1650
E-Mail: b.keimer@fkf.mpg.de

TRISP
Phone: +49 (0)89 289-14816

Operated by

MPG

Publications

Find the latest publications regarding TRISP in our publication database iMPULSE:

impulse.mlz-garching.de

Citation of the instrument

Max-Planck-Institut für Festkörperforschung and Heinz Maier-Leibnitz Zentrum. (2015). TRISP: Three axes spin echo spectrometer. Journal of large-scale research facilities, 1, A37. http://dx.doi.org/10.17815/jlsrf-1-41

For citation please always include the DOI.

Gallery

TRISP
TRISP
© W. Schürmann, TUM
Linewidth of a dispersive excitation
Linewidth of a dispersive excitation

Figure 1: Measurement of the linewidth of a dispersive excitation at TRISP: The TAS background spectrometer defines a resolution ellipsoid in the (q, ω)-space (blue ellipse), the spin-echo enhances the energy resolution within the resolution ellipsoid. Tuning of the spin-echo resolution (red line) to the group velocity of excitations is achieved by rotating the RF spin flip coils. A detailed analysis of the resolution properties is given by K. Habicht et al., J. Appl. Cryst. 36, 1307 (2003).

Linewidths of transverse acoustic phonons
Linewidths of transverse acoustic phonons

Figure 2: Linewidths of transverse acoustic phonons along q = (ξ, ξ , 0) in Pb at selected temperatures. Several anomalies are visible, which are not predicted by state-of-the-art ab initio calculations (gray symbols). (P. Aynajian et al., Science 319, 1510 (2008)).

Intrinsic magnon linewidth
Intrinsic magnon linewidth

Figure 3: Intrinsic magnon linewidth Γ in antiferromagnetic MnF2 at temperatures ranging from 15 to 40 K, as a function of q. We have plotted [Γ (T, q) – Γ (3 K, q)], where Γ (3 K, q) is given in the inset. (S. Bayrakci et al., Science 312, 1927 (2006))

Temperature dependence of magnetic and electronic contributions
Temperature dependence of magnetic and electronic contributions

Figure 4: Temperature dependence of magnetic and electronic contributions, a2, of the lattice constant of MnSi at various pressures measured by Larmor-diffraction. The inset displays changes of the lattice constant at ambient pressure versus T2 as normalized to a0 = 4.58Å. The relative resolution is Δd/d=1.5×10-6 (C. Pfleiderer et al, Science 316, 1510, (2008)).

MLZ is a cooperation between:

Technische Universität München> Technische Universität MünchenHelmholtz-Zentrum Hereon> Helmholtz-Zentrum Hereon
Forschungszentrum Jülich> Forschungszentrum Jülich

MLZ is a member of:

LENS> LENSERF-AISBL> ERF-AISBL

MLZ on social media: