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 H supply 110 VAC 2 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