V.S. Gurov - Dr. Sc. (Eng.), Professor, Head of Department «Industrial electronics», Rector of the Ryazan State Radio Engineering University. E-mail: gurov.v.s@rsreu.ru
M.V. Dubkov - Ph.D. (Eng.), Associate Professor, Head of Department «General and Experimental Physics», Deputy rector of the Ryazan State Radio Engineering University. E-mail: dubkov.m.v@rsreu.ru
M.A. Burobin - Ph.D. (Eng.), Associate Professor, Department «General and Experimental Physics», Ryazan State Radio Engineering University. E-mail: burobin.mikhail@yandex.ru

Boundary fields significantly affect the analytical parameters of quadrupole mass analyzers, primarily reducing transmittance. Usually, this effect is attributed to the fact that the ions passing through the transition region, and receive an additional offset transverse velocity component, which results in reduced transmission of quadrupole mass filter (QMF). It also leads to decrease of the shape of mass peak and to reduction the resolution of QMF. In this work the influence of the longitudinal component of the boundary field on the resolution, sensitivity and quality factor (the product of the resolution of the intensity of the mass peak) of the quadrupole mass filter is investigated. Investigations show that reducing the influence of the boundary field on analytical parameters of the quadrupole mass filter can be achieved using the input and output aperture as close to the ends of the electrodes and, in the limit placed deep into the quadrupole electrode system. Furthermore, the decrease of the input aperture reduces the influence of the boundary field due to a decrease of the energy spread of introduced ions. The experimental results demonstrated the possibility of improving the characteristics of the quadrupole mass analyzer at change the input aperture in the plane of the ends of the electrodes. Achieved an increase of resolution to 1,8 times and the sensitivity is reached twice, which increased the quality factor of 3,6 times.