Complex sentence: By the 1970s, atomic vapors were used in atomic vapor quantum counters for detection of infrared electromagnetic radiation, as they were found to be superior to the metallic salts and crystals that had been used.
Split into simpler sentences: By the 1970s, atomic vapors were used in atomic vapor quantum counters for detection of infrared electromagnetic radiation. Atomic vapors were found to be superior to the metallic salts and crystals that had been used.