We report the design and the performance of a compact dopant source that combines silicon, beryllium, and carbon tetrabromide in a single port of a molecular-beam-epitaxy system. This design relies on the rapid thermal response of the silicon and beryllium source materials and the rapid response to valve operation of the carbon tetrabromide flux to form abrupt junctions, rather than on shuttering. It features disks of silicon and beryllium without crucibles for low thermal mass and rapid radiative heating and cooling, thermocouples riveted directly to the disks for accurate temperature tracking, and a water-cooled molybdenum baffle to isolate the silicon and beryllium cells. Secondary ion mass spectroscopy analysis of dopant profiles and the I-V characteristics of GaAs p-n junction diodes indicate negligible dopant overlap in Be/Si p-n junctions made without the use of a shutter. Doping density for silicon and beryllium in GaAs varied less than 3% across the central 56 mm diam of a 76 mm (3 in.) wafer. We have used this source in our Gen II molecular-beam-epitaxy system over the past year for the growth of abrupt doping profiles, p-12 junctions, high electron mobility transistors, and heterojunction bipolar transistors in arsenide and phosphide materials.