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Methoden und Instrumentierung Poster: Mi., 14:00–16:30 M-P32
Application of ultrasound to multi crystal neutron diffractometer
Eugene Iolin 1 , Leonid Rusevich 1 , Markus Strobl 2 , Wolfgang Treimer 2 ,
Pavul Mikula 3
1 Institute of Physical Energetic, Riga, Latvia – 2 Hahn-Meitner Institute, Berlin, Germany
– 3 Nuclear Physics Institute, Re near Prague, Czech Republic
It is known that high frequency ultrasound increases the intensity by quasi elastic
scattering in single crystals accompanied by a loss of the impulse resolution. It was
supposed (E.I., 1989) that resolution losses could be avoided by exciting ultrasound
with the same frequency in single crystal monochromator and analyzer of a diffractometer.
Neutron absorbed (emitted) N ultrasonic phonons in monochromator and
resonantly emitted (absorbed) the same N ultrasonic phonons in analyzer. We realized
such experiment with a double crystal, DC, diffractometer with Si(111) crystals
(neutron wavelength 0.523 nm) and observed ∼ 60 % intensity increase in the peak of
the instrumental curve.
Simultaneously a strong improvement of the ultrasonic phonon satellite (-5