Building on the experience that Mampe gained with his ultra-cold neutron (U
CN) storage bottle MAMBO I (Phys. Rev. Lett. 63 (1989) 593), the successor
experiment MAMBO II has been designed and set up. The basic method of this
experiment relies on the storage of UCN in a rectangular glass vessel of va
riable size with walls covered by Fomblin oil. A preliminary value for the
lifetime of 881.0 +/- 3 s has been measured. (C) 2000 Elsevier Science B.V.
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