Skip to Content

Florentines Produce a New Form of Gelato

[Historical report created from GSU BEC Homepage:]

"BEC has been observed in 87Rb at LENS - European Laboratory for Nonlinear Spectroscopies, in Florence, Italy, on June 10th, 1999.

We employ a double MOT experimental set-up, directly inspired by the one adopted at JILA by E. Cornell's group, originally designed for experiments on Potassium and converted to Rubidium in Decembre 1998. The laser sources are a Ti:Sapphire and diode laser. The magnetic trap is a three coils (plus an extra antibias coil) IP trap running at 240 A, 11 V. Oscillation frequencies are 13 Hz and 190 Hz and the trap lifetime is about 50 s.

For 40 s we collect about 2 x 109 atoms in the second MOT, with 2 shots/sec from the first MOT. After compression and a molasses phase, atoms are optically pumped in the |F MF> =|2,+2> Zeeman level. Then we switch on a quadrupole magnetic field, which is converted in IP trap by gradually ramping up the current in the curvature and antibias coils in about 1 s: the overall loading efficiency from the MOT to the final harmonic trap is about 30%. Our evaporation lasts 45 s, later we switch off the magnetic field in less than 1 ms and, after 7 to 25 ms of free fall, we shine some resonance laser light to obtain an absorption image of the atomic cloud. We end up with 2 x 105 atoms in the condensate; the observed critical temperature is about 100 nK.

The BEC experiment has been carried out by:

  • Chiara Fort
  • Francesco Minardi
  • Marco Prevedelli
  • Francesco S. Cataliotti (now in Garching)
  • Massimo Inguscio

Other people involved are:

  • Guglielmo Tino (University of Napoli)
  • Leonardo Ricci (University of Trento)
  • Eric Cornell (JILA, Boulder)
  • Jason Ensher (now University of Connecticut)

Further details will be available at our web page. "