Sequoia LISST-200X, Руководство пользователя

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LISST-200X Introduction & Quick Start 4 LISST-
200X User’s Manual
B.
LISST-200X General Description
Instrument
Description The primary measurements delivered by the LISST-200X are the small-
angle scattering properties of particles in water, the laser optical
transmission, depth, and temperature. The LISST-200X is capable of
autonomous operation when used with external batteries. Windows
software is provided to program the instrument for a specific sampling
schedule. An auxiliary connector can be configured for recording data
from an external devices such as fluorometer, or for producing
summary data (mean size and total concentration) as analog voltages.
For details of the possible configurations of the Auxiliary Port, see
Appendix E: Connectors on page 84.
After recovery of the instrument, small-angle scattering data are off-
loaded from the instrument and subsequently
inverted mathematically
on a computer to produce the particle size distribution. The inversion
function is included in the Windows software. For MATLAB users,
inversion scripts are available for download from Sequoia’s website:
www.SequoiaSci.com .
The LISST-200X instrument is a laser diffraction device. It consists of
optics for producing a collimated laser beam, a specially constructed
detector array, electronics for signal pre-amplification and processing,
data storage and scheduling computer, and an external battery system.
The principal measurement
—angular scattering distribution— is
obtained over 36 ring-detectors whose radii increase logarithmically
from 102 to 20,000 microns. The detector is placed in the focal plane of
the receiving lens. The rings cover an angular range from 0.00085 to
0.34 radians. This angular range corresponds to size ranges from 1.00
to 500 µm. See Appendix B: Particle Size Bins on page 78 for more
information.
The LISST-200X consists of the following parts: a solid-state diode
laser operating at 670 nm wavelength and fiber-optically connected to a
laser beam collimating system, a beam manipulation and orienting
system, a two pressure windows, a scattered-light receiving lens, the
custom designed 36-ring detector, preamplifier electronics, a ring-
selecting multiplexer circuitry, and a digital controller with data memory.
All these components are inside the black-anodized pressure housing.
The LISST-200X does not have internal batteries. Its watertight
housing need not be opened for any normal use.