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Tyrex-2

Polarised helium-3 filling station

TYREX before TYREX-2

The “Tyrex” filling station for nuclear polarisation of 3He gas was constructed at the ILL during the period 2000-2002. The Tyrex machine uses metastability exchange optical pumping for polarising the 3He gas at about 1 mbar pressure. The gas is then compressed up to several bars via a hydraulic titanium-alloy piston compressor. The machine could provide about 1.3 bar.l/h of 75-80% polarised gas.

Image 1: Compressor

  • Powerful hydraulic actuator under closed-loop computer control
  • Velocity: 30 cm/sec, final position within 3 µm precision
  • Polarisation Preserving Piston and Chamber: Titanium alloy, 11 cm diameter and 55 cm stroke
  • Total displacement: 5200 cm3, compression ratio: > 15000

Image 2: Laser

  • Infrared Yb-fiber laser (All-fiber V-Grove Tech.)
  • Optimised for helium gas 23S1-23P transition (1083 nm, 2 GHz bandwidth)
  • Power : 50W (five 10W units)

Image 3: Magnetic field

  • 9 coils of 2 m diameter
  • Field amplitude: 10 Gauss
  • Homogeneity region:  diameter 0.9 m, length 2.5 m
  • Relative field gradient : < 1.2 10-4 cm-1

Imge 4 & 5: Performances and production

  • 83% polarisation in static mode
  • 77-80% on neutron beam
  • Production rate:  1.3 bar-litre / hour
  • Final pressure: up to 4 bar