[Zurück]

Ch. Gösselsberger, M. Bacak, T. Gerstmayr, S. Gumpenberger, A. Hawlik, B. Hinterleitner, E. Jericha, S. Nowak, A. Welzl, G. Badurek:
"Wavelength-selected neutron pulses formed by a spatial magnetic neutron spin resonator";
Poster: Polarised Neutrons in Condensed Matter Investigations, PNCMI 2012, Paris, Frankreich; 02.07.2012 - 05.07.2012.

We present a novel type of spatial magnetic neutron spin resonator for precise wavelength-selection and definition of the time structure of thermal and cold neutron beams. This device exploits the fact that upon passage of polarised neutrons through a spatially alternating transverse static magnetic field each neutron in its rest frame experiences an alternating field with a frequency depending on the neutron velocity and the spatial period of the resonator. If this frequency equals the Larmor precession frequency a resonant spin flip will take place. This property is used to pick out a desired wavelength band of adjustable width from an initially polychromatic neutron beam. The time structure of this neutron beam can be tailored from continuous operation to ultra-short pulses in the microsecond regime by application of a travelling magnetic wave mode. Thus, this new type of pulsed neutron magnetic spin resonator may be useful for polarised neutron beamlines both at continuous as well as short- and long-pulse spallation sources. It is of clear advantage that the time structure of neutron pulses produced by this method will be almost arbitrarily adjustable by purely electronic means. To demonstrate the feasibility of this technique, we designed and engineered a first prototype consisting of ten individually ultra-fast switchable aluminium stages for the generation of neutron pulses in the microsecond regime [1]. This resonator was installed at a polarised neutron beamline at the 250 kW TRIGA reactor of the Vienna University of Technology at the Atominstitut. Here we report on the results of a first test of this new type of magnetic neutron spin resonator.

References:
[1] C. Gösselsberger et al., J. Phys.: Conf. Ser. 340 (2012) 012028.
Neutron beam tailoring by means of a novel pulsed spatial magnetic spin resonator.

Neutronenspinresonator, polarisierte Neutronen, PERC, ESS