Wireless communication using detectors located inside vacuum chambers

Abstract

Progress in modern vacuum technology requires an increasing number of measurements to be performed in the vacuum environment itself and in many applications data transfer outside the vacuum vessels is both difficult and expensive. This paper explores the potential of wireless technology to transmit data from and into ultra high vacuum (UHV) compatible vacuum chambers using glass viewport windows attached to normal standard flange fittings. The current tests focus in particular on Bluetooth technology, and its characteristics and limitations investigated. Signal propagation has been verified up to about 9 m and the outgassing of components shown to be insignificant in a clean metal-sealed vacuum system down to a pressure of 10 −7 mbar. Some preliminary tests of noise and electromagnetic field immunity have been carried out, confirming the robustness of Bluetooth spread spectrum modulation technique. Signal data from Integrated Circuit Temperature Sensors and Photodiodes have been successfully transmitted from a vacuum chamber, proving the capability of this technology standard to handle both low and high frequency data. The future prospects and the further developments of the approach are also discussed.