TFXA spectrometer

Figure 7 Experimental and theoretical inelastic neutron scattering spectrum from staphylococcal nuclease at 25 K. The experimental spectrum was obtained on the TFXA spectrometer at Oxford. The calculated spectrum was obtained from a normal mode analysis of the isolated molecule. (From Ref. 28.)...

The spectra obtained for ice Ih, LDA and HDA, using the TFXA spectrometer at 10K [53] is shown in Fig. 11. Ice Ih is the most common and readily obtainable phase of ice which has now been well studied [14,15,48,49]. Its spectrum has a very simple structure, the translational modes below 40 meV are well separated from the librational modes (or hindered rotations) in the energy region between 65-125 meV (very few system shows similar behaviour and this is due to the large mass difference between O and H). The observed acoustic phonon peak is at 7 meV. The two sharp peaks at 28 and 37 meV are the optic-phonon bands and have an unusual triangular-shape. In contrast, only a single feature appears in the IR spectrum, at 27 meV, and the Raman spectrum has an additional shoulder at 36 meV (see Fig. 10). 

Figure 26.12 The inelastic neutron scattering spectrum ofa-MnHoo7 measured at 23 K on the TFXA spectrometer (Rutherford-Appleton Laboratory). Inset the arrangement of closely spaced pairs of 12e sites in the unit cell of a-Mn [126],...

Figure 11. Inelastic neutron scattering powder spectra of four isotopomers of BA at 5 K recorded with the TFXA spectrometer at ISIS (Rutherford Appleton Laboratories). The spectra are normalized for the mass of the samples and the total incident neutron flux. The differences in intensity are due to the differences in scattering cross section of the isotopes. (Adapted from Horsewill et al. [156].)...

Of the low final energy crystal analyser instruments, there were several early spectrometers that incorporated some of the elements found in current machines. The first instrument to include all the elements was installed at KENS (Tsukuba, Japan) in die early 1980 s [18]. Similar instruments were commissioned over the next decade NERA-PR at IBR-2 (Dubna, Russia) [24], CHEX at IPNS (Argonne, USA) [25] and TFXA at ISIS (Chilton, UK) [26]. The operating principle of all these... 

J. Penfold J. Tomkinson (1986). Rutherford Appleton Laboratory Report RAL-86-019. The ISIS time focused crystal spectrometer, TFXA. 

Fig.30. INS spectra of bulk pyrrole obtained with the spectrometers (a) TFXA and (b) INlBeF and of pyrrole adsorbed in (c) Na-Y and (d) Rb-Y the asterisks indicate the most intense peaks, cf. text (from [585])...

As an example, Fig. 30 shows the INS spectra of pyrrole in different states [585]. The INS spectra of bulk pyrrole were recorded at 5 K with the spectrometer INlBeF at the Institut Laue-Langevin (Grenoble, France) and at improved resolution with the spectrometer TFXA at the Rutherford Appleton Laboratory (Oxford, UK). 

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