Journal of large-scale research facilities, 1, A37 (2015) http://dx.doi.org/10.17815/jlsrf-1-41

Published: 18.12.2015

TRISP: Three axes spin echo spectrometer

Max-Planck-Institut für Festkörperforschung
Heinz Maier-Leibnitz Zentrum

Instrument Scientists:
- Thomas Keller, Max-Planck-Institute for Solid State Research, Stuttgart, Germany

at Heinz Maier-Leibnitz Zentrum (MLZ), Garching, Germany, phone: +49(0) 89 289 12164,
email: t.keller@fkf.mpg.de

- Bernhard Keimer, Max-Planck-Institute for Solid State Research, Stuttgart, Germany,
phone: +49(0) 711 689 1650, email: b.keimer@fkf.mpg.de

Abstract: TRISP, operated by the Max-Planck-Institute for Solid State Research, is a high-resolution
neutron spectrometer combining the three axes and neutron resonance spin echo (NRSE) techniques.

1 Introduction

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 improve-
ment of the energy resolution of one to two orders of magnitude.

TRISP also incorporates the Larmor di�raction (LD) technique, which allows to measure lattice spacings
with a relative resolution ∆d/d = 1.5 · 10-6, i.e. one to two orders of magnitude better than conventional
neutron or X-ray di�raction. 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.

2 Typical Applications

• Measurement of the intrinsic linewidths of phonons
• Measurement of the instrinsic linewidths spin excitations
• Larmor di�raction is used to determine thermal expansion and second order stresses under pres-

sure and at low or high temperature

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Journal of large-scale research facilities, 1, A37 (2015) http://dx.doi.org/10.17815/jlsrf-1-41

Figure 1: Instrument TRISP (Copyright by W. Schürmann, TUM).

3 Sample Environment

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

4 Technical Data

4.1 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 �lter

4.2 Monochromator

• PG(002) or (004)
variable focussing horizontal and vertical

4.3 Analyzer

• PG(002)
variable horizontal focussing

• Heusler (111) (polarised neutrons)
variable horizontal focussing

4.4 Spin echo

• Resonance spin echo, enclosed by mu-metal magnetic screen.

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http://dx.doi.org/10.17815/jlsrf-1-41
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http://dx.doi.org/10.17815/jlsrf-1-41 Journal of large-scale research facilities, 1, A37 (2015)

Figure 2: Schematic drawing of TRISP.

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	Introduction
	Typical Applications
	Sample Environment
	Technical Data
	Primary beam
	Monochromator
	Analyzer
	Spin echo