Optical Spectroscopy Instrumentation Design
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in digital measurements some conditioning, such as filtering or amplifying the analog signal, is usually necessary to make it suitable for recording by the ADC. In photon counting
systems, the recorded signal is the number of pulses observed or counted. Photon counting
is particularly useful in applications where the signal irradiance is relatively low, such as
photoluminescence measurements.
5.4.7 Data Collection, Display, and Analysis Software
At the most basic level, spectroscopic software must allow for reliable, efficient collection and storage of data with minimal sacrifice of hardware performance. As spectroscopy
increases in complexity and importance in everyday activities, software is becoming more
important. Today, software often needs to be sufficiently flexible to adapt to varied applications, yet simple enough for the increasing number of users with limited spectroscopic
backgrounds. More sophisticated software packages provide users with several options in
data display and analysis. This must include the possibility to record, display, calculate, and
then utilize spectral response curves on the excitation and emission channels. In addition,
the software must be suitably flexible to provide these correction curves under a variety
of different operating conditions such as changes in spectral bandpass, scan steps, signal
levels, and so on. The task is not straightforward and attention to detail is critical. Too
often the instrument software from manufacturers will assume “black box” operation and
present a “result” without the rigor of knowing whether it is the “true” result or whether it is
influenced by the optical spectral variations in instrument to instrument caused by spectral
properties of the light source, the illumination and collection optics, and the wavelength
performance of the analyzing spectrometer and detector.
It is the successful combination of the light sources, light discriminators, coupling
optics, and sampling and detection methods that provides an optimal system. This hardware package, coupled with a complete robust software analysis package and the correct
instrument calibration and correction functions, is the path to a successful instrument and
successful fluorescence measurements.
5.4.8 Instrument Performance Validation
In many laboratories, the performance validation of a fluorimeter instrument is still in its
infancy, and the influence of the many parameters involved in the instrument operation is
often not considered principally because it is thought that the instrument manufacturers
have taken care of this problem in their software. In reality instrument performance validation must also be the responsibility of the users to ensure the instrument meets their needs
and has not drifted with time. With this in mind, users might undertake a series of standard
measurements using one or more of the following:
Instrument calibration standards – physical sources such as line and tungsten lamp emis•
sions, known instrument independent luminescence standards, and so forth
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in digital measurements some conditioning, such as filtering or amplifying the analog signal, is usually necessary to make it suitable for recording by the ADC. In photon counting
systems, the recorded signal is the number of pulses observed or counted. Photon counting
is particularly useful in applications where the signal irradiance is relatively low, such as
photoluminescence measurements.
5.4.7 Data Collection, Display, and Analysis Software
At the most basic level, spectroscopic software must allow for reliable, efficient collection and storage of data with minimal sacrifice of hardware performance. As spectroscopy
increases in complexity and importance in everyday activities, software is becoming more
important. Today, software often needs to be sufficiently flexible to adapt to varied applications, yet simple enough for the increasing number of users with limited spectroscopic
backgrounds. More sophisticated software packages provide users with several options in
data display and analysis. This must include the possibility to record, display, calculate, and
then utilize spectral response curves on the excitation and emission channels. In addition,
the software must be suitably flexible to provide these correction curves under a variety
of different operating conditions such as changes in spectral bandpass, scan steps, signal
levels, and so on. The task is not straightforward and attention to detail is critical. Too
often the instrument software from manufacturers will assume “black box” operation and
present a “result” without the rigor of knowing whether it is the “true” result or whether it is
influenced by the optical spectral variations in instrument to instrument caused by spectral
properties of the light source, the illumination and collection optics, and the wavelength
performance of the analyzing spectrometer and detector.
It is the successful combination of the light sources, light discriminators, coupling
optics, and sampling and detection methods that provides an optimal system. This hardware package, coupled with a complete robust software analysis package and the correct
instrument calibration and correction functions, is the path to a successful instrument and
successful fluorescence measurements.
5.4.8 Instrument Performance Validation
In many laboratories, the performance validation of a fluorimeter instrument is still in its
infancy, and the influence of the many parameters involved in the instrument operation is
often not considered principally because it is thought that the instrument manufacturers
have taken care of this problem in their software. In reality instrument performance validation must also be the responsibility of the users to ensure the instrument meets their needs
and has not drifted with time. With this in mind, users might undertake a series of standard
measurements using one or more of the following:
Instrument calibration standards – physical sources such as line and tungsten lamp emis•
sions, known instrument independent luminescence standards, and so forth