An achromatic quadrupole lens system of a novel design is described. A triplet configuration with symmetric focusing property, i.e. equal demagnification in both directions, was used. Achromatic lenses are obtained by combination of magnetic and electrostatic quadrupole lenses. The internal electrostatic lenses are of a very compact design which suppress the 12- and 20-pole harmonic contamination of the quadrupole field The achromatic focusing property has been verified experimentally and the potential of the developed triplet lens at a future Nuclear Microprobe setup is discussed.