DHR/AR Series SALS Accessory Getting Started Guide
Page 12
Product Description
The laser used in the SALS Accessory is a Class II 0.95 mW diode laser, wavelength 635 nm, circular
beam with diameter of 1.1 mm, beam divergence (typical) 0.7 mrad.
The upper geometry is a 50 mm diameter x 2 mm thick optical quartz disk, refractive index 1.457 at
635 nm. To comply with the criterion for the single-point correction for the parallel plate geometry [M.S.
Carvalho, M. Padmanabhan and C.W. Macosko,
J. Rheol.
38 (1994) 1925-1936], the laser is set at 0.76 x
the quartz disk diameter, i.e., 19 mm, from the axis of rotation of the disk.
The image sensor’s effective area is 6.6 mm x 5.3 mm, effective pixels 1280 x 1024, pixel size 5.2 µm
square.
Figure 4
SALS Accessory components.
(above) provides a schematic of the SALS accessory components. A schematic of the optical sys-
. The pinhole is set at the focal point for 635 nm parallel light of convex lens 2;
divergent or convergent light will not pass through to the sensor. The image point will, therefore, be at the
focal point for parallel light of the convex (DCX) lens 1 – planoconvex (PCX) lens – quartz disc – sample
system. The depth within the sample of this point will depend on the refractive index of the sample, and the
position of the adjustable planoconvex lens. It should be noted that as a pin hole has a finite size, the sensor
'sees' light from a cylinder rather than a single point.
Upper mounting plate
Polarizing ring
Camera chip
Pinhole
Lenses
Sapphire window
Filter draw
Laser
Quartz plate
Peltier plate
Smart Swap
