A large beam high efficiency radio frequency neutron spin flipper
| Autor: | R. W. Erwin, P. Tsai, M. T. Hassan, N. Hadad, W. C. Chen, Charles F. Majkrzak |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Review of Scientific Instruments. 92:063906 |
| ISSN: | 1089-7623 0034-6748 |
| DOI: | 10.1063/5.0045687 |
| Popis: | A design for a radio frequency (RF) neutron spin flipper obtained from magneto-static and neutron spin transport simulations is presented. The RF flipper constructed from this design provides a flipping probability of 0.999 or better for a beam size 6 cm wide and 15 cm high and a wavelength band between 0.4 and 0.6 nm. Three permanent magnet guide field sections with air gaps provide a linear field gradient along the beam propagation direction over a large cross-sectional area. An RF oscillator based on coupling the resonant coil of a Hartley oscillator to the excitation coil was developed, which provides a higher current and, thereby, a larger RF amplitude, as compared to a conventional RF power amplifier. Two opaque He3 neutron spin filters were employed to measure the flipping probability of the flipper with very high precision. A spatially uniform flipping probability of 0.9995(2) or higher was measured over the large cross-sectional area neutron guide. This RF neutron spin flipper will be employed in a polychromatic beam reflectometer at the National Institute of Standards and Technology Center for Neutron Research. This design can be applied to other polarized neutron instruments or applications requiring a very high continuous flipping probability of the neutron spin for a large cross-sectional area beam. |
| Databáze: | OpenAIRE |
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