Photomultiplier detector

Light from an appropriate light source (a xenon arc or a halogen or tun ten lamp) passes through a monochromator (probe monochromator). The exit intensity at wavelength "k, IqCK), is focused onto the sample by means of a lens (or mirror). Tbe reflected light is collected by a second lens (mirror) and focused onto an appropriate detector (photomultiplier, photodiode, etc.). For simplicity, the two lenses (mirrors) are not shown in Figure 2. For modulated transmission the detector is placed behind the sample. 

Colorless substances absorb at wavelengths shorter than those of the visible range (the UV range normally amenable to analysis X = 400...200 nm). Such compounds can be detected by the use of UV-sensitive detectors (photomultipliers. Sec. 2.2.3.1). Substances that absorb in the UV range and are stimulated to fluorescence or phosphorescence (luminescence) can be detected visually if they are irradiated with UV light. 

Ch - chopper disc, Fhl - filter holder, D - iris diaphragm and interchangeable pinholes of various sizes, Sch - sample chamber, S - sample holder, ID - iris diaphragm, L2 - receiver lens, Ph2 - detector photomultiplier, A - measuring arm, Fh 2 - filter holder, Phi - detector photomultiplier... 

There are two ways to collect FLIM data freqnency-domain or time-domain data acqnisition (Alcala et al. 1985 Jameson et al. 1984). Briefly, in freqnency domain FLIM, the fluorescence lifetime is determined by its different phase relative to a freqnency modulated excitation signal nsing a fast Fourier transform algorithm. This method requires a frequency synthesizer phase-locked to the repetition freqnency of the laser to drive an RF power amplifier that modulates the amplification of the detector photomultiplier at the master frequency plus an additional cross-correlation freqnency. In contrast, time-domain FLIM directly measures t using a photon connting PMT and card. 

Figure 13.5 The diverse components of a single beam atomic absorption apparatus. Model IL 157(Thermo JarreU Ash) constructed during the 1980s. 1, source (spectral lamp) 2, flame hurner which provides the atomic aerosol 3, monochromator grating and 4, detector (photomultiplier). The source illuminates a sht situated at the entrance the dispersive system. The exit sht, is close to the detector window. It determines a narrow bandwidth of the spectrum, (AA of 0.2 to 1 nm), which must not he confused with either the width of the exit slit or with the image of the entrance sht.

Detector Photomultiplier Solid state, charge transfer device... 

ICP-AES is a technique of measurement used for the detection and determination of elements with the aid of atomic emission. The solution for measurement is atomized and the aerosol is transported into an inductively coupled plasma (ICP) with the aid of a carrier gas. There, the elements are excited such that they emit radiation. This is spectrally dispersed in a spectrometer and the intensities of the emitted element lines are measured by means of detectors (photomultipliers). A quantitative statement is possible by means of calibration with reference solutions, there being a linear relationship between the intensities of the emission lines and the concentrations of the elements over a broad range (usually several powers of ten). The elements may be determined either simultaneously or consecutively. 

CL is well observable using optical microscopy as well as SEM. Worthwhile results can be obtained when a CL detector (photomultiplier) is coupled with a monochromator. The recording of CL-spectra allows differentiation of inorganic pigments and extenders which otherwise vary only in the type or number of lattice defects (e.g., vacancies, trace activators on interstitial lattice sites, etc.). 

The emission of the excited analytes in the plasma is polychromatic (several different wavelengths per analyte). The spectrophotometers used to detect and quantify the emitted radiation contain a monochromator (polychromator for simultaneous measurements at several different wavelengths) and a detector (photomultiplier tube) to quantify the amount of radiation for each specific wavelength. 

When illuminated with monochromatic radiation a single monochromator usually shows continuous stray light of the order of 10" of the intensity of the monochromatic radiation. Therefore, 2 or 3 monochromators in series combined with additive dispersion reduce the stray radiation by about 10 or 10 , respectively. However, the intensity of the Raman lines is also reduced when passing a monochromator Since every monochromator has a transmittance only of about 30%, this means that a double monochromator has only a transmittance of 9%, a triple monochromator of 2.7%. Such monochromators are usually very voluminous and expensive. However, they are widely used for recording of Raman spectra with single detectors (photomultipliers). 

The intensity of scattered light (see Fig. 1) may be measured as a function of the scattering angle, 9, and the azimuthal angle, (y+cj)). Since it is very difficult to lift the detector (photomultiplier) out of the horizontal plane, the angles... 

Detector photomultiplier tube thermal, pyroelectric, bolometers... 

The phase-separated structures of the DPB/PB mixtures were observed by LSCM with an incident laser beam wavelength A of 364 nm. A band pass filter (395-440 nm) installed in front of the detector (photomultiplier) was used to detect only fluorescence from the anthracene molecules that were labeled only to the PB. The PB phase was recognized as a bright phase under the fluorescent LSCM (see Fig. 10). The intensity of fluorescence from a particular point in a focal plane (x-y or lateral plane) at a given depth z, I x,y,z), was recorded by the detector behind a pinhole ( confocal pinhole ) which efficiently excludes out-of-focus light, thus achieving an excellent depth resolution. Here, the z -axis denotes the optical axis of the micro-... 

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