The development of an ultra-cold neutron (UCN) source at the Institut Laue-Langevin (ILL) based on super-thermal down-scattering of a cold neutron beam in superfluid helium is described. A continuous flow, self-liquefying helium-3 cryostat was constructed and tested with a beryllium-coated prototype converter vessel with a vertical, window-less extraction system on the PF1b cold neutron beam. A new UCN magnetic trap for neutron lifetime measurements made from an array of permanent octupole magnets, a superconducting coil assembly, with vertical confinement by gravity, is also described. The cleaning of above-threshold UCNs and depolarization is discussed and studied experimentally with the magnet array and a fomblin-coated piston valve on the PF2 UCN source at the ILL. The possibility of detecting the charged decay products is also discussed.
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The development of an ultra-cold neutron (UCN) source at the Institut Laue-Langevin (ILL) based on super-thermal down-scattering of a cold neutron beam in superfluid helium is described. A continuous flow, self-liquefying helium-3 cryostat was constructed and tested with a beryllium-coated prototype converter vessel with a vertical, window-less extraction system on the PF1b cold neutron beam. A new UCN magnetic trap for neutron lifetime measurements made from an array of permanent octupole magne...
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