We have designed a silicon detector based on an avalanche photodiode for detecting vacuum ultraviolet radiation. It was demonstrated that the detector has a photon detection efficiency superior to 0.65  electrons  /  photon, in the wavelength range from 114 to 170 nm, with an external quantum yield from 49 to 7000  electrons  /  photon at a reverse-bias voltage from 190 to 315 V, respectively. The detector’s active area diameter is 1.5 mm.