Figure 2.

Wavelength distribution in the neutron guide system of KWS-2 simulated using McStas, showing the white beam before the velocity selector (green line) and the beam after the velocity selector rotating at a speed of 28 200 r min⁻¹ and with different tilt angles (blue: −10°; black: 0°; brown: +10°); the symbols represent simulations at the end of the ‘S-shaped’ guide, for the same tilting angles; the red lines denote the fits of the Gaussian distributions which delivered the Δλ/λ for the three setups. The transmission factors for the three different wavelengths can be directly determined from the figure.