Magnetic lens of the prismatic beta spectrometer of the Tbilisi State University

Reconstruction of magnetic lenses was aimed at the increase of the luminous intensity without any weakining of the resolution. Winding with trapezoid form distribution of linear density of ampere-windings, placed directly on the vacuum tube of the spectrometer was chosen. Focus distance of the new lenses was imposed to be equal to 155-160 cm. The winding was made a conductor of rectangular cross-section 1.95x3.8 mm. Large cross-section of the conductor and good isolation excluded the necessity of special cooling of lenses. The length of the inner layer of the winding is equal to 1650 mm, of the outer layer - 840 mm, linear density of the windings in the middle of the lens is 31 cm. Experimental values of the field distribution in lenses as well as other electronic-optical parameters are correlated well with the calculated data within the limits of the errors