Each Venera spacecraft carried two dedicated gamma-ray burst detectors, arranged for full sky coverage. Each detector consisted of a 4.5×3.7 cm NaI(Tl) crystal surrounded by an 8 mm thick plastic anti-coincidence jacket. The crystal and plastic were viewed from the side by photomultiplier tubes.

The gamma-ray burst detector operated in low time resolution “waiting” modes in the absence of a burst; low energy resolution spectra and higher energy resolution calibration spectra were transmitted in this mode. Typically, the data were accumulated into 120.0 s time bins, 1-31 energy channels. Detection of a burst triggered the storage of high time resolution count rates and spectral data.

The trigger criterion was an excess count rate 8 sigma above normal in a 250 ms interval. During a burst, there were 1-6 energy channels used, and, for a “typical” burst seen with Venera 11 & 12, the nominal energy range was 80–800 keV. The readout time was ∼4 s. However, two successive bursts could only be detected if the interval between them was 3–20 minutes. In addition, the storage of information on-board the spacecraft limited the number of distinguishable bursts to 1 every 2 hours.

KONUS on Veneras 11 & 12 consisted of 6 scintillation detectors, a set of 6 devices for gamma-ray burst detection against the current background, 6 counters to measure the count rate in each sensor, a 320-channel time analyzer, and a 128 channel PHA. Each scintillator was a NaI(Tl) crystal with 80 mm diameter and 30 mm thickness. The background was measured over the energy range 50–150 keV for count rate, and over the range 30 keV — 2 MeV for spectra. Eight seconds of pre-burst data was recorded when a trigger was issued, with a resolution of 0.25 s. The temporal profile of the burst was recorded in 3 ways: 2 s with 15.625 ms resolution, 32 s with 0.25 s resolution, and an additional 32 s with 1 s resolution. The PHA trigger mode was a 16 channel, quasi-logarithmic energy scale mode which measured 8 energy spectra in 8 successive intervals of 4 s each. The threshold sensitivity at the 6-sigma trigger level was ∼4 × 10^-7 erg/cm².