<p num="48">FIELD: physics.</p> <p num="49">SUBSTANCE: invention relates to neutron supermirror polariser. Polariser consists of a transmission neutron polariser and a second neutron super-mirror polariser located close to the transmission neutron polariser. Newly introduced polariser provides high negative polarization of the beam at a wide angle range exceeding the total angular width of the beam incident on the polariser input, and which is made in the form of a multichannel neutron guide with straight channels in the form of a set of plates compressed between each other without air gaps, which are made of material which weakly absorbs neutrons. Device design is made so that neutrons (-) of beam spin component are reflected from walls of second polariser with high reflection coefficient, and neutrons (+) of spin component – with low coefficient of reflection. This will lead to suppression of peaks (+) of the spin beam component, which worsen polarization of the beam at the output of the first polariser.<