Salsa

Strain imager for engineering applications

Guide hall 1, thermal guide H22

Monochromators
type	double-focusing bent Si-crystal monochromator
dimensions	209 x 170 x 12 mm³
wavelength range	1.3 - 3 Å
variable take-off	55° - 125°
horizontal curvature radius	2.68 m
vertical curvature radius	1.5 m - ∞

Sample stage
hexapod max. load		500 kg
workspace		other data
translation x,y	± 300 mm	max. distance to beam	460 mm
z	150 mm	rigid translation	700 mm
tlit (χ, φ)	± 30°	rigid rotation (Ω)	360°
rotation (ω)	± 45°

Beam defining optics
primary slit :
apertures computeur controlled	0.3 mm - 5 mm horizontal
manual (fixed)	0.3 mm - 50 mm vertical
distance to gauge volume	0 - 600 mm, motorised
secondary slit :
apertures computer controlled	0.3 mm - 5 mm horizontal
manual	25, 50 mm vertical
distance to gauge volume	0 - 200 mm, motorised
radial collimators
primary and secondary focus (full width at half maximum)	0.6 mm and 2 mm (horizontal and vertical)
distance to gauge volume	150 mm, 380 mm, 420 mm
oscillation	± 1°

Detector
type	2-dimensional Position Sensitive microstrip Detector
active area	80 x 80 mm²
readout	256 x 256 channels
angular step	0.02° (at 1 m sample-detector distance)
distance to gauge	0.5 - 1.5 m

Instrument Description

SALSA is a diffractometer which enables the measurement of internal strain (residual and applied) in engineering materials. The instrument uses a monochromatic beam and a Position Sensitive Detector (PSD), which covers 4° in 2θ at a typical distance of 1 m from the sample.

Sample dimensions can vary from a few millimetres to over a metre. The sample stage is a 6-axis ‘hexapod’ which is able to support samples of over 500 kg and perform complicated spatial scans. A 360° rotation (omega) is available around a vertical axis through the ˝gauge volume˝. To assist sample alignment and programming of complex scans, SALSA makes use of the Coordinate Measurement Machine (CMM) of the ILL-ESRF material science support laboratory.

Two options for beam size definition are available: computer controlled variable slit systems and radial focusing collimators. The primary and secondary slit systems allow beam size variations between 0.3 mm and 5 mm horizontally and up to 25 mm vertically. A range of collimators are available with foci as small as 0.6 mm (FWHM) and a fixed distance to the gauge volume of 150 mm. Collimators are particularly useful for high spatial resolution measurements near interfaces, surfaces or in coatings, since they give lower surface aberrations.

The neutron beam is delivered via a double focusing monochromator composed of 39 silicon variably bent crystals, each 5 mm high, 170 mm long and 12 mm thick. Its total height is 209 mm, corresponding to the guide dimensions (30 × 200 mm). Thanks to phase space focusing, it takes advantage of the beam divergence provided by the neutron guide and supplies the high resolution needed for strain determination. Changing the horizontal curvature and/or the take-off angle allows the use of high-intensity or high-resolution configurations. The optimum neutron flux is at λ = 1.66 Å, which is ideal for a many typical of engineering materials.

Two in-situ (and offline) stress rigs are available a 5 kN vertical/horizontal mounting machine for small samples and a 50 kN horizontally mounting machine for static or dynamic (fatigue) tests.