PHASE TRANSFER BETWEEN 230 AND 690 GHz

Simultaneous observations with dual receivers (230/690 GHz) are supported at the SMA. This is a nice feature for observations at high frequency. At high frequencies of submillimeter wavelengths, strong calibrators become rare. The phase variation due to changes of water vapor in the atmosphere might be monitored by the observation of a calibrator at lower frequency (230 GHz). The 690 GHz phase appears to be linearly correlated with the phase at 230 GHz under normal circumstances. The phase variation monitored at 230 GHz might be transferred to 690 GHz. The transferred phase variation might be used to correct for phase variation in the observation at 690 GHz. This technique requires a good stability of the instruments at both 230 and 690 GHz. Based on the experiments in the spring 2005, a procedure for the phase transfer between 230 and 690 GHz is provided below for the off-line calibration concerns: