Title :
An evaluation of the collisional frequency shift in a 87Rb cold atom fountain
Author :
Sortais, Y. ; Bize, S. ; Nicolas, C. ; Santos, M. ; Mandache, C. ; Santarelli, Giorgio ; Salomon, C. ; Clairon, A.
Author_Institution :
Lab. Primaire du Temps et des Frequences, Paris, France
Abstract :
We describe the operation of a laser cooled 87Rb frequency standard and present a new measurement of the 87Rb ground state hyperfine frequency with a relative accuracy of 2.4×10-15, by comparison with a Cs fountain primary standard. The measured frequency is 6 834 682 610.904 35(1.7)Hz. The have measured the frequency shift induced by cold collisions in 87 Rb. It is at least 150 times smaller than for 133Cs. Finally, we report a test of a possible variation of the fine structure constant at the level of 2.7×10-14 yr-1, comparing Rb and Cs cold atom fountains
Keywords :
atomic clocks; frequency standards; ground states; hyperfine structure; laser cooling; rubidium; 6834682610.9045 Hz; 87Rb cold atom fountain; 87Rb ground state hyperfine frequency; Cs cold atom fountains; Rb; accuracy; cold collisions; collisional frequency shift; fine structure constant; frequency shift; laser cooled 87Rb frequency standard; Atom optics; Atomic beams; Atomic measurements; Charge carrier processes; Frequency measurement; Masers; Optical attenuators; Phase noise; Stationary state; Testing;
Conference_Titel :
Frequency and Time Forum, 1999 and the IEEE International Frequency Control Symposium, 1999., Proceedings of the 1999 Joint Meeting of the European
Conference_Location :
Besancon
Print_ISBN :
0-7803-5400-1
DOI :
10.1109/FREQ.1999.840701
