|Incident wavelengths||2.0 - 14.0 Å at 10 Hz|
|Momentum transfer, Q||Depends on sample-detector distances and detector offsets: Qmin~0.002 Å-1, Qmax~3 Å-1|
Notes for proposers:
- Users are expected to provide their own sample cuvettes/cans. But where necessary, some quartz cuvettes are available for loan. Please discuss with the instrument scientists. ISIS does not endorse any particular manufacturer of quartz cuvettes but both Hellma (stock codes: 110, 120 & 404; material codes: QS/QX) and Optiglass (stock codes: 21 & 32; material code: Q) manufacture suitable products.
If the ratio of H:D present in a hydrogenous sample is more than 50% H the sample path-length (thickness) should not exceed 1 mm (or absorbtion, incoherent and inelastic scattering effects may manifest themselves). Otherwise path-lengths of 2 mm are acceptable. In predominantly deuterated and/or very dilute samples 5 mm path-lengths can be used. Exceptionally 10 mm path-lengths may be necessary.
The volumes required for different 1 mm path-length cells are approximately (minimum in brackets):
10 mm wide rectangular - 0.25 ml (0.15 ml)
20 mm wide rectangular - 0.55 ml (0.40 ml)
disc-shaped ('banjo') - 0.25 ml (0.25 ml)
The advantage of disc-shaped cells and the 20 mm wide rectangular cells is that a larger diameter neutron beam can be used, increasing the count rate on the sample, where appropriate.
RK Heenan, SM King, DS Turner & JR Treadgold, SANS2D at the ISIS Second Target Station, Proc ICANS-XVII (2006), 780-785