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Another report from Japan

Nakagawa graph

[Historical report created from GSU BEC Homepage:]

"This report just in from the University of Electro-Communications in Tokyo:

We observed BEC in 87Rb, |F = 2, MF = 2> state, on December 19, 2001.

Our experimental apparatus consists of a double MOT and a QUIC (Quadrupole and Ioffe Configuration) type magnetic trap developed by the Hansch group.

We first collect about 5 x 108 atoms in the 2nd MOT in 30 seconds. Then the MOT is compressed and further cooled by a polarization gradient cooling. After optical pumping to the | 2 2> state, the quadrapole trap is activated within 1 ms and the quadrapole coil current is increased to the maximum value of 25 A. The trap is converted to a Ioffe-Prichard type trap within 1 s. The rf eveporation cooling is applied for 30s. When we swept the rf frequency from 25 MHz to around 910 kHz, which was about 10 kHz higher than the frequency that emptied the trap, we observed condensed atoms in absorption images of TOF(6ms) atom clouds.

Figure above: Absorption images for a sequence of different final rf knife frequencies.

Summary of our operating parameters:

  • species: 87Rb, |F = 2, MF = 2>
  • double MOT and a QUIC type magnetic trap
  • number of atoms in the 2nd MOT : 5 x 108
  • loading time: 30s
  • number of atoms in the magnetic trap : 2 x 108
  • lifetime of the magnetic trap: 90s
  • number of condensed atoms : about 105

Our members:

  • Munekazu Horikoshi
  • Takayuki Iio
  • Yamao Nakajima
  • Masamichi Tamura
  • Ken'ichi Nakagawa

Former members:

  • Osamu Uehara
  • Noritsugu Shiokawa

Further information will be soon available from our web site.

Ken'ichi Nakagawa "