How do I construct a maser?
So I have mentioned before about my plans to build a HERF gun using a magnetron powered by a highspeed motor w/ permanent magnets that serves as a generator(it's driven by a minature gas turbine engine). But the issue of collimating the microwaves into a beam that can travel at least 4 miles without significant diffraction is an issue I'm still working on. Now magnetrons have an efficient of roughly 70%. So here's the idea: The magnetron's output coupling loop(antenna) will be inserted into a highly tempered glass cylinder that is attached to the top of the magnetron and the cylinder will be filled with either hydrogen gas or (anhydrous)ammonia. The oscillating RF field will pump the gas molecules at their microwave region resonant frequencies(if I use ammonia that will mean I need the magnetron to produce peak power at 24 GHz)and stimulate microwave emission by the molecules(population inversion). Has this technique ever been demonstrated experimentally? I know that RF radiation can be used to heat up hydrogen gas into plasma but maybe there are some references to masers constructed in this fashion.