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NSF: Triple Axis Spectrometer (TAS)



BT7 Schematic (MB)
Schematic of NSF on BT-7 with End-compensated Magic Box as polarizer device.


The schematic shown above illustrates the use of NSFs on the BT-7, triple axis spectrometer. In this configuration, a NSF is used as both the polarizer and the analyzer. On the polarizer side (upstream of sample), a 3He cell is located inside a mumetal shielded box or "MAGIC" Box or a mumetal shielded solenoid. On the analyzer side (downstream of sample), a 3He cell is located inside a mumetal shielded solenoid. The polarization of each 3He cell is monitored using in-situ NMR. All Triple Axis publication can be found here.

Powerpoint slide provided for presentation use: Neutron Spin Filters on BT-7


Specifications or NSF on BT-7 Triple Axis
BT-7 w/SCM
  • 3He cell as polarizer and analyzer
  • 3He polarization flipping capability
  • Elastic and inelastic measurements
  • Sample field magnitude: H ~ 10G
    • P \({\parallel}\) Q or P \({\perp}\) Q
  • Superconducting Magnet field: up to 2 T
  • Four cross-section polarization efficiency correction
    • both horizontal and vertical field
  • 3He transmission: \({\leq}\) 50% (for desired spin state)
  • Flipping ratio: \({\leq}\) 60



Spin Filters


Created May 17, 2018, Updated July 2, 2020