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Design and Performance Evaluation of the Atomic Hydrogen Maser for Chinese Mobile VLBI Station

The hydrogen maser is the most stable frequency standard generally available today for all but the shortest measuring time. It is an essential frequency reference standard for radio astronomy. The information about the design and specifications of a new generation of the H maser for Chinese mobile VLBI station is provided, including the improvement of the cavity bulb, magnetic shields, and atomic beam optics. The performance measurements show that its f?r?e?q?u?e?n?c?y s?t?a?b?i?l?i?t?y i?s b?e?t?t?e?r t?h?a?n 1×10 -14 for time interval from 80 s to 1 d.