Angular encoding with Larmor precession

Abstract

The first test of angular encoding of a neutron beam with Larmor precession was performed at the spin-echo set-up of ZETA on IN3 (ILL, Grenoble, France). The polymer multilayer sample exhibits specular and off-specular scattering previously measured with reflectometry. The Yoneda scattering was discriminated from the specular reflection employing the angular encoding. The scans of the reflected and the off-specular scattered intensities as a function of the spin-echo length reveal its sinusoidal intensity dependence and the phase relation with respect to each other. The phase shift between the off-specular scattering and specular reflected intensity produced the wanted and necessary angular resolution. An estimation of the effective resolution abilities of this method in reflectometry kinematics yields that the angular encoding including subsequent deconvolution is useful for any divergent or convergent incoming or outgoing beam in order to separate signals.