2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/193481We present studies on electron backscattering from the surface of plastic scintillator beta detectors. By using a setup of two detectors coaxial with a strong external magnetic field - one detector serving as primary detector, the other as veto-detector to detect backscattering - we investigate amount and spectrum of unrecognized backscattering, i.e. events where only one detector recorded a trigger signal. The implications are important for low energy particle physics experiments.5 pages, 8 figures; v2: published NIM A versionInstrumentation and Detectorstext