干旱区生态环境知识资源中心

The Atacama Large Millimeter Array (ALMA) project requires the development of reliable quasi-optical systems with requirements similar to the ones in space. The operating condition for optical elements of higher frequency channels are similar to the conditions in spacecraft, since these elements are contained within the ALMA cryostat in high vacuum and at cryogenic temperatures. The remote terrain of the Atacama Desert and the scale of project suggest that a significant effort should be made to ensure high reliability of the system. Therefore the techniques, common to a space mission are applied with this development.

In this report we would like to present the design of the quasi-optical system for ALMA band 9 (600-702 GHz) containing elements typical to a space system. A design assumptions and details will be presented for a frequency independent system. A measurement of near field antenna beam pattern (phase and amplitude) will be presented and comparison with theoretical predictions will be made.