Novel type of neutron polarization analysis using the multianalyser at PUMA implementation, characterization and first experiments

by Steffen Schwesig
Doctoral thesis
Date of Examination:2019-08-16
Date of issue:2019-11-07
Advisor:Prof. Dr. Götz Eckold
Referee:Prof. Dr. Götz Eckold
Referee:Prof. Dr. Simone Techert
Persistent Address: http://dx.doi.org/10.53846/goediss-7722

 

 

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Abstract

English

The PUMA polarization analysis introduces a new method for polarization analysis with neutrons, for the first time allowing the simultaneous measurement of both spin states by detecting spin-up and spin-down neutrons in different detector channels. Detecting both spin states at the same time can lead to a reduction in beam time necessary for a given experiment with polarized neutrons. In addition to this unique feature, the simultaneous detection of both spin states is very useful for kinetic experiments as one can directly observe the change of both spin components depending on the current state of the sample. It is also a mayor boon if one is interested in an experiment where, for the required information it is difficult to guarantee the same conditions for the two measurements in a conventional polarization setup. The new PUMA setup eliminates these experimental problems and is the first time a three axis spectrometer has the capability to measure both spin states at the same time.This work details the development of the PUMA polarization analysis, as well as its implementation and first experiments. Magnon spectra in different phases and Brillouin-zones of multiferroic CuO are measured to show the capabilities of the new system.
Keywords: Three axis spectrometer; Neutron scattering; Neutron polarisation analysis; Instrumentation development; Magnons in copper oxide; Kinetic investigations with polarized neutrons
 
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