High luminosity time of flight with polarisation analysis: CeCu6
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Date
2007-07-15
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Elsevier
Abstract
The magnetic excitation spectrum of the heavy fermion system CeCu6 has been obtained by pseudo-randomly chopping the polarisation of the beam on LONGPOL and measuring the time of flight with polarisation analysis before the detectors. Separation of the magnetic part of the spectrum was made by changing the polarisation direction at the specimen. This method achieves a greater luminosity at the specimen compared with conventional methods at the expense of a background proportional to the total scattering from the specimen. The form of the spectrum is as expected with two transitions and considerable inelastic intensity centred oil zero energy transfer. The crystal field spectrum of the Ce3+ ion is considerably broadened by the Kondo nature of the system. An analysis of the experimental accuracy was made based on the statistical variation between the runs which make up the experiment. LONGPOL is a very slow instrument, based as it is on a thermal source with an incident wavelength of 3.6 A. The demonstrated possibility to obtain a spectrum incorporating polarisation analysis provides a basis to evaluate the usefulness of future implementation. © 2007, Elsevier Ltd.
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Keywords
Fermions, Crystal field, Polarization, Time-of-flight spectrometers, Scattering, Neutrons
Citation
Harker, S. J., Hicks, T. J., Kennedy, S. J., & Yu, D. H. (2007). High luminosity time of flight with polarisation analysis: CeCu6. Paper presented to the Sixth International Workshop on Polarised Neutrons in Condensed Matter Investigations (PNCMI 2006), 25-28 September 2006, Berlin, Germany. In Pappas, C., Prokes, K., Siemensmeyer, K., & Wiedenmann, A. (Eds), Physica B: Condensed Matter, 397(1-2), 15-19. doi:10.1016/j.physb.2007.02.069