Abstract: We created software to simulate the Larmor precession in a setup for SESANS with adiabatic/radio frequency flippers in magnets designed to measure the time-of-flight on pulsed or stationary neutron sources. The values and spatial configurations of the magnetic fields of the existing prototype magnets we used as input data. For an empty setup, we calculate the polarization of a “divergent ribbon beam” 2 cm high, depending on the neutron wavelength λ. In the “scattering experiment”, we show how to convert λ to the “spin-echo length” δ. For λ = 10 Å, flippers at a distance of 140 cm and a radio frequency 1 MHz we find δ ≈ 10 μm. Extension to δ = 20 μm is realistic.@en

We made software to simulate Larmor precession in a setup for SESANS with adiabatic/RF flippers in magnets, existing at PNPI. The final polarisation of a divergent “ribbon beam” of height 2 cm is calculated as a function of λ. For λ= 6 A, flippers 56 cm apart and RF frequency 1 MHz we find spin-echo length δ= 0.9 μm. We show numerically, how λ is converted to δ. Extension to δ= 20 μm is realistic.@en