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Atomic Clock Development at PTB
Andreas Bauch
PTB (Physikalisch-Technische Bundesanstalt)
Time Dissemination
Working Group
UFFC Distinguished
Lecturer 2006/2007 PTB is engaged in development and operation of
atomic clocks since many decades. I will briefly describe the "old"
clocks which are still in operation and which still contribute substantially to
the steering of TAI. The first PTB fountain was operational in 2000. Recently
some new insights in possible frequency shifts were obtained which have been
throroughly studied. I will present the results to the extent that they are
definite and conclusive. Last not least does PTB investigate in optical
frequency standards. We have realized two trap systems which have been
intercompared. Also absolute optical frequency measurements with respect to the
fountain have been performed. The results contribute to an improved estimate of
the possible variation of the fine structure constant alpha with time.
I will begin my talk with a brief introduction to
the principles of atomic clocks and the measures we typically use to
charaterize their performance. |