Disclosed herein is a method for improving the precision of a test result from an instrument with an optical system that detects a signal. The method comprises including in the instrument a normalization target disposed directly or indirectly in the optical path of the optical system. Also disclosed are instruments comprising a normalization target, and systems comprising such an instrument and a test device that receives a sample suspected of containing an analyte.

A calibration data acquisition unit uses an equation X=YW in which an optical spectrum matrix X is the same as a product between a component natural spectrum matrix Y and a component amount matrix X, performs independent component analysis in which column vectors of the component amount matrix W are treated as independent components so as to determine the component natural spectrum matrix Y, and employs row vectors of a general inverse matrix Y.sup. of the component natural spectrum matrix Y as component calibration spectra corresponding to a plurality of components. A calibration curve is created by using a target component calibration spectrum corresponding to a target component.

A calibration reference for a multipass Raman analysis system, wherein a combination excitation and collection beam passes through a focal point F.sub.0 within a sample volume multiple times, is provided. The calibration reference includes a body of material having a known spectral response when illuminated by the combination excitation and collection beam. The size or shape of the body is selected or modified to keep the focal point at F.sub.0 within the body when the body is positioned within the sample volume for calibration purposes.

Disclosed is a calibration curve setting method for setting a calibration curve, the calibration curve setting method including: creating a first calibration curve on the basis of a measurement value obtained by measuring a standard sample for which a concentration of a predetermined component is known; creating a second calibration curve by correcting the created first calibration curve; displaying a screen configured to support an operator for restoring the second calibration curve to the first calibration curve; receiving an instruction of restoring the second calibration curve to the first calibration curve; and displaying the first calibration curve upon receiving the instruction of restoring.

Disclosed herein is a method for improving the precision of a test result from an instrument with an optical system that detects a signal. The method comprises including in the instrument a normalization target disposed directly or indirectly in the optical path of the optical system. Also disclosed are instruments comprising a normalization target, and systems comprising such an instrument and a test device that receives a sample suspected of containing an analyte.

A method for determining a degree of damage to hair is provided in the form of various embodiments. Said method can comprise the following steps: during the exposure of a hair sample to UV light (for example by employing a UV-LED), detecting fluorescence light emitted by the hair sample, determining a fluorescence intensity by employing the detected light, and determining the degree of damage to the hair using said fluorescence intensity.

This application discloses a method and an apparatus for the measurement of gases in hydraulic fracking sites, comprising a gas sensor, a computer, and a correction factor wherein the correction factor is applied to the observed gas reading to generate a more accurate reading of the gas level at the site.

Sensor and Measurement Method A turbidity sensor and method of measuring turbidity is provided. The turbidity sensor (100) comprises first and second optical detectors for detecting a respective optical response of each optical signal. The first optical detector (20) may be arranged in direct view of the emitter (10) and the second optical detector (30) may be arranged in indirect view of the emitter (10). The two detectors collect light emitted from the emitter (10) when directed through a fluid sample during two optical tests run in very close succession. Firstly, a control sample is illuminated to determine a calibration factor for the control sample with known turbidity. Then, the calibration factor is used to determine the turbidity of a fluid sample with unknown turbidity. Advantageously, background radiation during the data collection process is ignored because the transient behaviour during each optical test is negligible. The approach is more convenient over known turbidity sensors and measurement methods, particularly in light of the calibration step.

A method for optimizing values of n detection wavelengths of an optical gas sensor configured to detect n different gases is provided, including: a) calculating a value of a determinant of an absorptivity matrix whose coefficients represent spectral absorptivity of each of the n different gases at the n detection wavelengths, the calculating being repeated several times, each time modifying at least one of said n detection wavelengths so the values of said n detection wavelengths are comprised within a range of values for which the spectral absorptivity of at least one of the n different gases is non-zero; and b) determining the values of said n detection wavelengths for which the calculated value of the determinant of the absorptivity matrix corresponds to a maximum calculated value amongst a set of values calculated in step a).

A carbon concentration can be measured using a small number of calibration curves even for a silicon wafer containing oxygen at a high concentration. A calibration curve determination method includes determining calibration curves using data sets each including a plurality of data, each data including irradiation dose, oxygen concentration, carbon concentration, and luminescence intensity, the data of each data set having the same irradiation dose and the same oxygen concentration, and the data sets being different in at least one of the irradiation dose and the oxygen concentration, selecting one or more combinations each being a pair of the calibration curves which are equal to each other in the irradiation dose and different from each other in the oxygen concentration, and obtaining a difference between slopes of the paired calibration curves on a log-log plot for each combination.