Xenon Supplier to St. Louis A colorless, odorless, nontoxic, inert gas.Xenon (Xe) is often considered as the rarest of the rare gases. Xenon exists in the atmosphere at an average concentration of about 87 parts per billion (ppb) by volume, or 0.087 parts per million (ppm). It is collected, with Krypton, in the oxygen fraction of an air separation plant. In larger facilities, the Krypton-Xenon fraction is collected for further purification and distillation.As may be imagined from its extremely low concentration, Xenon is expensive to recover and purify. This cost and overall small annual production rate limits its use significantly, primarily to very small volumes in specialized lighting, such as the small light bulbs that are used in automobile headlight, and in specialized imaging equipment in healthcare, primarily for scanning the brain. A patient will breathe an Oxygen-Xenon mixture immediately prior to, and during the CT scanning process. This procedure is becoming widely accepted in assessing blood flow through the brain, in the case of traumatic brain injury, and also reviewing damage from strokes. Small amounts of Xenon are also used in nuclear physics research.