time-nuts@lists.febo.com

Discussion of precise time and frequency measurement

View all threads

An idea for an active rubidium maser

AK
Attila Kinali
Sun, Nov 6, 2016 7:46 PM

Hi,

I just had a stupid idea: What if, one would modify a rubidium fountain
to launch the atoms not trough two Ramsey cavities, but into an elongated
resonant cavity? Ie pump the Rb atoms as it is done with a normal fountain
and launch them into the cavity, where they can interact with the field
for a probably a second or so (would result in an height of approximately
one meter) then fall out trough another hole.

The big advantage of this approach is that the atoms follow a predetermined
path and thus there are no wall collisions. The atom-atom collisions are
still there, but not worse than in a normal fountain. Additionally one
can choose a path where the field is constant and thus avoid a lot of
problems. I guess the cavity would need a Q factor higher than 100k,
of which I have no idea whether that's possible. Assuming one needs
about 1pW of output power and conservatively assuming only 10% of the
atoms interact with the field during that second (I have no idea how to
calculate that) something like >1e12 atoms per second would be needed.
Given that usual launched molases are in the order of 1e7 to 1e9 atoms,
that sounds doable.

So, who is with me to build one of these? :-D

		Attila Kinali

--
Malek's Law:
Any simple idea will be worded in the most complicated way.

Hi, I just had a stupid idea: What if, one would modify a rubidium fountain to launch the atoms not trough two Ramsey cavities, but into an elongated resonant cavity? Ie pump the Rb atoms as it is done with a normal fountain and launch them into the cavity, where they can interact with the field for a probably a second or so (would result in an height of approximately one meter) then fall out trough another hole. The big advantage of this approach is that the atoms follow a predetermined path and thus there are no wall collisions. The atom-atom collisions are still there, but not worse than in a normal fountain. Additionally one can choose a path where the field is constant and thus avoid a lot of problems. I guess the cavity would need a Q factor higher than 100k, of which I have no idea whether that's possible. Assuming one needs about 1pW of output power and conservatively assuming only 10% of the atoms interact with the field during that second (I have no idea how to calculate that) something like >1e12 atoms per second would be needed. Given that usual launched molases are in the order of 1e7 to 1e9 atoms, that sounds doable. So, who is with me to build one of these? :-D Attila Kinali -- Malek's Law: Any simple idea will be worded in the most complicated way.