MASER Microwave Amplification by the Stimulated Emission of Radiation Power Matters Some Uses of Hydrogen Masers • Timing Laboratories • International Time UTC • Local Oscillators for Atomic Fountains • Radio Astronomy • Relativity Experiments • GPS Ground Stations Power Matters Active Device Power Matters Maser Block Diagram 28.75 Hz Varactor MPG Control IF Amp L.O. Multiplier Receiver -105 dBm Amplifier 5.751 KHz Phase Detector & 5.751 KHz 10 MHz VCXO 14 digit Tuning Maser 10 MHz Synthesizer Physics VaractorPackage Switching 10 MHz Varactor 10 MHz Signal Buffers 10 MHz 405 KHz Cavity Synchronous Register 28.75 Hz Detectors U/D Source Hydrogen 24 V Power Pressure Source Battery Module Control 110 VAC 110 VAC H2 supply 24-29 VDC Palladium Purifier Power Matters Maser Diagram Storage bulb Cavity Magnetic shields State selector H H2 Source bulb Purifier/valve Power Matters Ground State Hydrogen Atom Energy Level Diagram Power Matters Magnetic State Selector Power Matters Hydrogen Storage Bulb • Centrally located in cavity • Approximately 1-2 Liters • Generally made of Quartz • Teflon Coated – Minimal perturbation to atoms from wall collision • H atoms stay in the bulb about 1 second – Travels on the order of 1 Km – Makes on the order of 10 4 bounces off the wall Power Matters TE011 Cavity Mode Loop orthogonal to field line couples signal out of cavityr B Electric Field Lines Magnetic Field Lines Power Matters Maser Q’s ∆f • Atomic line Q Q=f/ ∆f 9 –Ql is approx. 2x10 • Cavity Q f –Qc is approx. 40,000 • About 20k needed to sustain oscillation -5 •Qc /Q l is approx. 2x10 Power Matters Active Hydrogen Maser Stability Power Matters Maser Operating Lifetime Power Matters Maser Outline Power Matters Hydrogen Maser Summary • Very Good Short Term Frequency Stability • Low Phase Noise Option • “Mature” Technology • Very Long Service Life • Field Serviceable Power Matters.