COMPACT ACTIVE HYDROGEN MASER

PSI PROPOSES TO TEST THE FEASIBILITY OF AN ACTIVE COMPACT HYDROGEN MASER OSCILLATOR. RECENT ADVANCES IN HIGH TEMPERATURE SUPERCONDUCTORS MAKE POSSIBLE THE REALIZATION OF MICROWAVE RESONANT CAVITIES WITH HIGH QUALITY FACTORS AND ONLY 2% OF THE VOLUME OF THOSE USED IN EXISTING MASERS. THE RESULTING REDUCTION IN SIZE AND WEIGHT OF HYDROGEN MASERS IS CRITICAL TO THEIR APPLICATION IN SPACE SYSTEMS SUCH AS GPS. THIS SUPERCONDUCTING RESONATOR HAS ALREADY BEEN CONSTRUCTED AND TESTED. IT IS A COMPACT LOOP-GAP DESIGN AND HAS A QUALITY FACTOR THAT IS MORE THAN 3 TIMES LARGER THAN A COPPER VERSION OF THE RESONATOR MEASURED AT THE SAME TEMPERATURE AND FREQUENCY. IT HAS BEEN SHOWN THAT THE FREQUENCY STABILITY OF A COMPACT ACTIVE MASER OPERATING AT 77K HAS THE SAME OR BETTER FUNDAMENTAL LIMIT OF FREQUENCY FLUCTUATIONS, DUE TO THERMAL FLUCTUATIONS WITHIN THE HYPERFINE LINEWIDTH. CALCULATIONS SHOW THAT IF THIS LEVEL IS REACHED (AND NOT LIMITED BY SYSTEMATIC FLUCTUATIONS), THE STABILITY WILL BE BETTER THAN 1 PART IN 10X15 AT 2000 SECONDS (ALLAN DEVIATION). IN PHASE I, WE WILL COMPLETE THE TESTS AND INVESTIGATIONS NECESSARY TO DESIGN THE PROPOSED OSCILLATING MASER.