Detector structure

A high resistance photo-conductive detector structure is disclosed in US-A-4731640. An n-type photosensitive layer connected via two n+-type regions is disposed between two blocking regions which confine electrons and holes within the photosensitive layer. The increase of the resistance of the photosensitve layer is accomplished by electrically depleting majority carriers, electrons, out of the photosensitive layer. 

A planar detector structure is presented in JP-A-6204449. The planar structure is achieved by forming HgCdTe regions in a silicon substrate. 

A detector structure which may be fabricated by planar processing and which permits fabrication of thin infrared detectors is shown in US-A-4197633. 

Aquatic HS PL Aquagel-OH 30 SEC column 80/20 (v/v) Water/methanol mixture with 10 mM NH4HCO3 DAD and ESI-MS detectors Structure of HS 45... 

For all detector types, the transfer of energy to the detector material as the photoelectrons and recoil electrons slow down occurs through excitation or ionization of electrons in neighboring atoms within the detector structure. What occurs next depends on the specific molecular structure of the detector. We can distinguish between structures such as noble gases, photoconductors, fluorescent phosphors, and photostimulable phosphors. 

Figure 4.8 The gas-flow proportional counter (a) A simplified representation of the detector structure, (b) The preamplifier-detector interface. (Reprinted by courtesy of EG G ORTEC.)...

Several variations in p-n junction photovoltaic detector structure have been investigated, such as heterojunctions in which the wider gap material transmits the incident radiation to the junction and narrower gap material, and junctions illuminated from the back side. However, although possibly improving quantum efficiency, these approaches do not provide performance fundamentally different from that of the model of Fig. 4.2. 

The Fan Beam Reconstruction. With a slit collimated fan beam of x-rays, a projection is formed by the illumination of a fixed line of detector cells. A common detector structure in this respect is the equally spaced collinear array. The projection data for this geometry is represented by the function P ), where )3 is the projection angle of a typical ray path SB and p is the distance along the detector line D,D2 to a point at B (Fig. 26.22). To simplify the algebra, the fan beam projection R ) is referred to the detector plane moved to DJ/Dj. The ray path integral along SB is now associated with the point A on this imaginary detector line aXp = OA (Fig. 26.23). 

The detector thickness should be as small as possible. This requirement is opposed to the previous one. Thin detector structures enable a shorter response time (because of the shorter transit time) and lower noise levels (because detector volume is decreased). 

It is only to be expected that some nonequilibrium detector stmctures have their analogs in semiconductor lasers. Exclusion detectors correspond to single-hetero-lasers, extraction devices to double-heterolasers, and magnetoconcentration detectors to lasers with the magnetoelectric photoeffect proposed by Marimoto et al. [331]. This inverse analogy is valid not only in electrical, but also in optical field, where e.g., resonant cavity (RCE) detector structures are connected with VCSEL lasers, and lasers with a PBG cavity with PCE (photonic crystal-enhanced) detectors. 

Detector structure is simple because it does not require nonstandard parts and additional external components. 

The n Hgi xCdxTe detector structure used to calculate cmrent sensitivity was the same as in Fig. 3.19. It can be seen that the increase of sensitivity follows the same pattern as noise current. This is logical, since in situations when the g-r component prevails the same mechanisms are responsible both for creation of signal current and for its fluctuations. 

On the other hand, the large current densities pose the problem of Joule heating and excess heat removal from the active area. One of the proposed solutions is a fabrication of the smallest possible detector structures. For instance, for a current density of about 2,000 A/cm with a detector about 10 pm thick and 50 pm wide its total dissipation would be about 5 mW. 

Since the carotenoids display similar absorption spectra it is recommended to identify these compounds after HPLC separation using a mass spectrometer or a NMR detector. Structural and geometrical isomers or epoxides were distinguished by this technique (Aman et al., 2005 Matsubara et al., 2012). An accelerated solvent extraction step in hexane-based solvent mixtures was successfully used prior to LC-ESl MS analysis of lutein and P-carotene from orange carrot (Saha et al., 2015). 

The first demonstration of BIB detector used arsenic-doped silicon (Si As) is the IBC material. A schematic cross-section of a basic Si As BIB detector structure is shown in Figure 1. 

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