PUMA: Thermal three axes spectrometer

Oleg Sobolev,Jitae T Park

doi:10.17815/jlsrf-1-36

Abstract

Three axes spectrometers allow the direct measurement of the scattering function S(Q, ω) in single crystals at well defined points of the reciprocal lattice vector Q and frequency ω and thus represent the most general instrument type. PUMA, which is jointly operated by the Institute of Physical Chemistry, Georg-August-Universität Göttingen and the Technische Universität München, is characterised by a very high neutron flux as a result of the efficient use of focussing techniques.

Highlights

Three di erent vertical openings and a horizontal slit with a maximum opening of 40 mm de ne the virtual source, which is two meters before the monochromator
Three axes spectrometers allow the direct measurement of the scattering function S(Q, ω) in single crystals at well de ned points of the reciprocal lattice vector Q and frequency ω and represent the most general instrument type
PUMA, which is jointly operated by the Institute of Physical Chemistry, Georg-August-Universität Göttingen and the Technische Universität München, is characterised by a very high neutron ux as a result of the e cient use of focussing techniques

Summary

Introduction

Three di erent vertical openings and a horizontal slit with a maximum opening of 40 mm de ne the virtual source, which is two meters before the monochromator. PUMA has a remote controlled monochromator changing unit which allows to place one out of four di erent monochromators inside the drum. An innovative option of the spectrometer is the multianalyzer/ detector system It allows a unique and exible type of multiplexing. A unique feature of the instrument is the possibility to perform stroboscopic, time resolved measurements of both elastic and inelastic signals on time scales down to the microsecond regime. Using this technique, the sample is periodically perturbed by an external variable such as temperature, electric eld, etc. The signal is recorded as a function of momentum and energy transfer, and given a time stamp, relative to the periodic perturbation

Typical Applications

Sample Environment