[time-nuts] Cs beam cavity: why is it U shaped?

[Attila Kinali]

Moin,

For some time now, i'm wondering why the microwave cavity of Cs
beam standards is U shaped. Ie why does the Cs beam fly first
trough the first "sub"cavity, leaves it, flies a substantial
length trough free space, passes the second "sub"cavity and
then goes to the detector.

If the interaction time with the microwave field would be an
issue, i would expect the beam to pass trough a longer stretch
of the cavity, and not two time trough a short stretch that
are widely spaced.

Unfortunately, none of the papers i've read has shed any light
on this, and google isn't helpfull either.

Could anyone here enlighten me?

			Attila Kinali

-- 
Why does it take years to find the answers to
the questions one should have asked long ago?