Precision absolute polarimeter development for the 3He$++$ ion beam at 5.0-6.0 MeV energy.

There is opportunity for precision measurements of the absolute $^{\mathrm{3}}$He$^{\mathrm{++}}$ polarization at beam energies 5.0-6.0 MeV after the EBIS Linac. The analyzing power for the elastic scattering of spin-1/2 particles ($^{\mathrm{3}}$He) on spin-0 particles ($^{\mathrm{4}}$He) can reach the maximum theoretical value A$_{\mathrm{N}}=$1 at some point (E$_{\mathrm{beam}}$, $\theta _{\mathrm{CM}})$. The main effort of this R@D will be development of precision absolute polarimeter for the measurements of the $^{\mathrm{3}}$He$^{\mathrm{++}}$ beam polarization produced in the EBIS as a reference for the further polarization measurements along accelerator chain. The polarimeter vacuum system is integrated in the spin-rotator transport line. The $^{\mathrm{3}}$He$^{\mathrm{++}}$ ion beam will enter the scattering chamber through the thin window to minimize beam energy losses. The scattering chamber is filled with $^{\mathrm{4}}$He gas at \textasciitilde 5 torr pressure. The silicon strip detectors will be used for energy and TOF measurements of the scattered $^{\mathrm{3}}$He and recoil $^{\mathrm{4}}$He nuclei (in coincidence) for the identification of the scattering kinematics.