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- Tremsin, A. S., et al.
(författare)
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High-Resolution Neutron Counting Sensor in Strain Mapping Through Transmission Bragg Edge Diffraction
- 2011
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Ingår i: IEEE Sensors Journal. - 1558-1748. ; 11:12, s. 3433-3436
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Tidskriftsartikel (refereegranskat)abstract
- High-resolution neutron counting sensors with microchannel plates coupled to a Timepix readout enable high spatial (similar to 55 mu m) and temporal (similar to 1 mu s) accuracy for each detected thermal and cold neutron. One of the attractive applications for those sensors is the high-resolution strain mapping in engineering samples through transmission Bragg edge diffraction. The unique combination of high detection efficiency (up to 70%), high spatial and temporal resolution of, detectors enable similar to 100 mu m strain mapping with similar to 100 mu strain accuracy. We present the results of proof of principle measurements performed at ROTAX beamline at ISIS spallation neutron source. Strain map of a bent steel sample is measured with very high spatial resolution. The same sensors enable high-resolution nondestructive studies in such diverse areas as neutron microtomography, dynamics of fuel injection, material composition, archaeology, water propagation and many others.
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| 3. |
- Tremsin, A. S., et al.
(författare)
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Imaging of dynamic magnetic fields with spin-polarized neutron beams
- 2015
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- Precession of neutron spin in a magnetic field can be used for mapping of a magnetic field distribution, as demonstrated previously for static magnetic fields at neutron beamline facilities. The fringing in the observed neutron images depends on both the magnetic field strength and the neutron energy. In this paper we demonstrate the feasibility of imaging periodic dynamic magnetic fields using a spin-polarized cold neutron beam. Our position-sensitive neutron counting detector, providing with high precision both the arrival time and position for each detected neutron, enables simultaneous imaging of multiple phases of a periodic dynamic process with microsecond timing resolution. The magnetic fields produced by 5- and 15-loop solenoid coils of 1 cm diameter, are imaged in our experiments with similar to 100 mu m resolution for both dc and 3 kHz ac currents. Our measurements agree well with theoretical predictions of fringe patterns formed by neutron spin precession. We also discuss the wavelength dependence and magnetic field quantification options using a pulsed neutron beamline. The ability to remotely map dynamic magnetic fields combined with the unique capability of neutrons to penetrate various materials (e.g., metals), enables studies of fast periodically changing magnetic processes, such as formation of magnetic domains within metals due to the presence of ac magnetic fields.
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