Sensitivity relative

For sensitivity detection the standard defectometers were used. Relative sensitivity comparison at steel objects radiographic control by radiation with energy of 25 and 45 MeV shows that sensitivity minimum for 45 MeV energy is very displaced towards the big thickness and has not yet reached its minimal meaning at 500mm thickness. 

The encircling probe was characterised with its mirror in water. As we did not own very tiny hydrophone, we used a reflector with hemispherical tip with a radius of curvature of 2 mm (see figure 3c). As a result, it was possible to monitor the beam at the tube entrance and to measure the position of the beam at the desired angle relatively to the angular 0° position. A few acoustic apertures were verified. They were selected on an homogeneous criteria a good one with less than 2 dB of relative sensitivity variations, medium one would be 4 dB and a bad one with more than 6 dB. 

Figure Bl.11.1. Resonance frequencies for different nuclei in a field of 14.1 T. Widths indicate the quoted range of shifts for each nucleus, and heights mdicate relative sensitivities at the natural isotopic abundance, on a log scale covering approximately six orders of magnitude. Nuclei resonatmg below 140 MHz are not shown.

The intensity of the reflected light must also be measured. Historically, this was done using the eye. Since, in general, a null (a measurement of the point at which the light decreases to zero) is required, this can be relatively sensitive. However, nowadays, the light intensity is generally measured using a photomultiplier tube. 

Other Nuclei. Although most nmr experiments continue to involve H, or both, many other nuclei may also be utilized Several factors, including the value of I for the nucleus, the magnitude of the quadmpolar moment, the natural abundance and magnetogyric ratio of the isotope, or the possibihty of preparing enriched samples, need to be considered. The product of the isotopic parameters can be compared to the corresponding value for providing a measure of relative sensitivity or receptivity. Table 1 summarizes these factors for a number of isotopes. More complete information may... 

The nitrifying organisms are relatively sensitive to many toxic organics, so that the treatment of industrial wastewaters requires special attention to the presence of toxics. 

Fig. 5. Calculated relationship between log (relative sensitivity) and log (crystal volume) for (—) intrinsic response (blue) and (------) dyed response (minus...

Isotope Nuclear spin Resonance frequency, MH2 Relative sensitivity Magnetic moment, 10 j/t ... 

Wavelengths of intrinsic sensitivity 1 Approximate relative sensitivity... 

Isotope Natural abundance (%) Nuclear spin Electric quadrupole moment NMR frequency fora 23.5 kO field (MHz) Relative sensitivity... 

Studies of the alkylation of indazoles (67HC(22)1) have been updated by Nunn (73JCS(PD2371) and Palmer (75JCS(P1)1695). The ratio of methylation at positions 1 and 2 is relatively sensitive to the steric effect of substituents at positions 3 and 7 as shown by the results obtained in basic medium for unsubstituted indazole (55 45) and its 3-phenyl (74 26) and7-nitro derivatives (29 71). 

Once the driver and driven equipment have been chosen and it is deter mined that none of the items will be subject to any lateral vibration problems, the system torsional analysis is performed. If a calculated torsional natural frequency coincides with any possible source of excitation (Table 9-21, the system must be de-tuned in order to assure reliable operation. A good technique to add to the torsional analysis was presented by Doughty [8 j, and provides a means of gauging the relative sensitivity of changes in each stiffness and inertia in the system at the resonance in question. 

The standardless approach attempts to apply first principles descriptions of X-ray production to the calculation of interelement relative sensitivities. Several of the key parameters necessary for first principles calculations are poorly known, and the accuracy of the standardless method often suffers when different X-ray families must be used in measuring several elemental constituents in a specimen. 

ISS involves simple principles of classical physics and is one of the simplest spectroscopy for quantitative calculations. Under most standard instrumental operating conditions there is essentially no dependency on the chemical bonding or matrix of the sample. Several workers have discussed quantitative aspects of ISS and ele-ihental relative sensitivities. These have been compiled with comparative measurements of sensitivity obtained from several different laboratories and are shown in... 

Several features of ISS quantitative analysis should be noted. First of all, the relative sensitivities for the elements increase monotonically with mass. Essentially none of the other surface spectroscopies exhibit this simplicity. Because of this simple relationship, it is possible to mathematically manipulate the entire ISS spectrum such that the signal intensity is a direct quantitative representation of the surface. This is illustrated in Figure 5, which shows a depth profile of clean electrical connector pins. Atomic concentration can be read roughly as atomic percent direcdy from the approximate scale at the left. 

Pragmatically, the relative concentrations of elements are determined from the measured ion beam ratios by the application of relative sensitivity factors, which are determined experimentally from standard samples ... 

In principle, therefore, the surface concentration of an element can be calculated from the intensity of a particular photoelectron emission, according to Eq. (2.6). In practice, the method of relative sensitivity factors is in common use. If spectra were recorded from reference samples of pure elements A and B on the same spectrometer and the corresponding line intensities are and respectively, Eq. (2.6) can be written as... 

Thus, as for XP S, the average surface concentration Na can, in principle, be calculated by measurement of the Auger current, according to Eq. (2.13). Again, as in XPS, relative sensitivity factors are generally used. The Auger current for the same transition XYZ in a standard of pure A is measured under the same experimental conditions as in the analysis of A in M, whereupon the ratio of the atomic concentrations is... 

Sa is the relative sensitivity factor. Normally, values of Sa are derived empirically or semi-empirically. Tables of such sensitivity factors have been published by Payling... 

Because measuring A can be problematic, quantification is normally performed by relative sensitivity factor (RSF) methods. If a species A on the surface is detected by the ion X , the ratio of the detected ion current /a(X ) to the primary ion current 7pi and the surface density 9 (A) is called the practical sensitivity factor Sp (X (A)) ... 

The most accurate - and most popular - method of quantifying matrix effects is to analyze the unknown sample with a similar sample of known composition. The relationship between measured intensity and the content of each sample is, usually, defined by the relative sensitivity factor (RSF) ... 

Values of Y (X (A)) for elements typically range from 10 to 10 in NR-laser-SNMS, and from 10 to 10 in R-laser-SNMS. If the experimental conditions are not well known, the concentration of A can also be quantified by using the relative sensitivity factor (RSF) method (Eqs (3.8) and (3.9) in Sect. 3.1.3). 

Tab. 3.1. NR-laser-SNMS Relative sensitivity factors S (Me, ESi) and detection limits DL for metals on Si wafer surfaces.

Ix is the background-corrected net intensity of the principal peak of analyte X, Kx a proportionality factor for the absolute sensitivity of the standard reference, e. g. an Ni plate, and c the concentration of X. Multielement analyses are based on known relative sensitivities S ... 

If relative sensitivity factors are used, reference measurement of standard samples is not necessary. The ratio of two different elemental concentrations in one sample is given by ... 

The ratio Db/Da is a so-called relative sensitivity factor D. This ratio is mostly determined by one element, e. g. the element for insulating samples, silicon, which is one of the main components of glasses. By use of the equation that the sum of the concentrations of all elements is equal to unity, the bulk concentrations can be determined directly from the measured intensities and the known D-factors, if all components of the sample are known. The linearity of the detected intensity and the flux of the sputtered neutrals in IBSCA and SNMS has been demonstrated for silicate glasses [4.253]. For SNMS the lower matrix dependence has been shown for a variety of samples [4.263]. Comparison of normalized SNMS and IBSCA signals for Na and Pb as prominent components of optical glasses shows that a fairly good linear dependence exists (Fig. 4.49). 

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