The design and details of construction of a proportional counter for use in counting gammarays in the high proportional region are described. The circuit diagrams for the preamplifier, the main video amplifier, and the stabilized high voltage supply are included. The counter is operated with pure argon, or with argon plus a little air, at 50‐cm pressure and about 1750 volts. When used with a coincidence circuit, employing blocking oscillators for sharpening the pulses, a resolving time of 4×10−8 second is obtained.