Larmor

Larmor is capable of operating in a number of different measurement configurations. Currently, SANS and SESANS are the primary operating modes. In order to swap between these configurations, it takes of the order of 2 to 3 hours after which the instrument must then be checked and calibrated. As a result, mode switching within an experiment is not encouraged although it is possible.

The main SANS detector consists of an array of 80 x 600 mm-long position-sensitive ³He tubes with an angular coverage of ~4° (vertical) x up to 8° (with horizontal offset), located 4.4 m from the sample. A second high count rate detector of 38 x 50 mm in size is installed for SESANS measurements, and an additional 1-dimension high-angle detector can be installed for wide-angle diffraction measurements.

2 v-cavity polariser options are available, allowing access to different wavelength ranges, and an additional SEOP polarised ³He cell can be installed for fully polarised SANS measurement. A supermirror bender is used to analyse the beam for SESANS measurements.

Incident wavelength range

• 0.9 – 13.0 Å or 0.5 – 12.5 Å unpolarised
• 1.9 – ~10.0 Å polarised with Polariser 1
• 3.0 – 13.0 Å polarised with Polariser 2

Momentum transfer

• 0.0035 – 0.7 Å^-1 with the beam centred in the middle of the detector
• 0.0035 – 1.0 Å^-1 with the beam offset at 2°

Incident wavelength range

• 1.9 – ~10.0 Å polarised with Polariser 1
• 3.0 – 13.0 Å polarised with Polariser 2

Possible Poleshoe Angles: 25 – 90°

Operating frequencies and fields

• 0.5 MHz – 17.14 mT
• 1.0 MHz – 34.28 mT
• 2.0 MHz – 68.56 mT

Spin-echo length range: ~100 nm – 38 µm