| Analysis |
The SOLAS device analyzes the
collected sample with the help of an XRF-analyzer. An isotope source
(e.g. Fe 55) or a x-ray tube excites the sample with its x-rays and the
spectrum is taken with energy-dispersive detector . From this spectrum
up to eight element-contents can be determined (elements from Al to U).
After the measurement is finished - which takes between 30 to 90 seconds
depending on the application - the sample is locked out of the analyzer
measuring chamber. The measuring chamber is washed with air and the next
sample, which has been collected in the meantime, is filled into the
measuring chamber. The acquired data are sent to the data-storage and
process-visualizing-system via glass fiber. Breaks in hauling, were no
samples must be taken, are used by the analyzing-device for
self-calibration with an incorporated standard-material. |
| Data-Processing |
The process-data acquisition
computer provides graphic representation of the received analytical data
and can be installed up to several miles apart.
The system (COROS by Siemens) provides data-storage of both analytical
data and technical information regarding the performance of SOLAS. It
allows the quick recognition of trends, gives an alarm in case given
limited values are passed over etc. At the end of a shift-protocol with
all analysis-data and shift-mean values is given. all working conditions
of the SOLAS-system as well as possible defects or mal-functions are
shown in a clear manner. |
| Longtime-Stability |
At the end of the calibration
for the particular task a set of synthetic standard-samples is measured,
which allows a checking/review of the XRF-analyzer's stability at any
time. In case of a defect the original calibration can be restored. |
| Calibration |
The calibration of the system
is usually done by presenting samples with known contents to the
sampling tube of the device. The range of contents should cover the whole
range of values in which the device is supposed to operate. During the
calibration the intensities determined by the XRF-analyzer (counts per
seconds for a chemical element) are related to the laboratory data for
the material. In most cases simple linear functions between the
intensities of the chemical element in question and the content in the
bulk material are found. |
