Photodiode array detector, silicon

Diode array detectors consist of silicon integrated circuit (IC) chips incorporating up to one or two hundred pairs of photodiodes and capacitors. Each photodiode measures about 0.05 x 0.5 mm and is sensitive to... 

The first measurement we make when starting a fluorescence study is not usually a fluorescence measurement at all but the determination of the sample s absorption spectrum. Dual-beam differential spectrophotometers which can record up to 3 absorbance units with a spectral range of 200-1100 nm are now readily available at low cost in comparison to fluorimeters. The wide spectral response of silicon photodiode detectors has made them preeminent over photomultipliers in this area with scan speeds of a few tens of seconds over the whole spectral range being achieved, even without the use of diode array detection. 

The use of a linear detector array in the image plane of a polychromator in place of the fluorescence monochromator in Figure 12.1 enables the parallel data accumulation of complete fluorescence spectra. Silicon photodiode arrays, operated in a CCD mode(34) are the most widely used detector elements. The spectral response of the diodes enables fluorescence to be detected from the near-UV up to ca. 1100 nm with a peak response in the near-IR. Up to 8192 elements are now available commercially in a single linear array at low cost. However, the small length of each element (ca. 10 [im) presently limits sensitivity and hence cylindrical lens demagnification is often necessary. 

The classical silicon photodiode linear array manufactured by Reticon was the first detector marketed successfully. Similar solid state linear array detectors based on charge coupled devices, or charge.injection devices may also be of interest. Typical of the families of detectors, the Reticon detectors are built in a number of elements/array sizes. Commercially available units have anywhere from 128 to 1024 elements/array. Each individual element in the array is 1 x 1 mil to 1 x 100 mil in area, and are spaced on approximately 1 mil centers. The spectrometer system discussed in this article was built using Reticon-type devices. 

The photodiode array detector is connected to a computer fitted with a suitable package to control the method, calculate and report the results. The photodiode array detector consists of 1000 or more silicon photodiodes arranged side by side on a single small silicon chip and absorption of electromagnetic radiation by a pn-junction causes promotion of electrons from the valence bands to the conduction bands and thus the... 

Widely used types of photon detectors include phototubes, photomultiplier tubes, silicon photodiodes, and photodiode arrays. 

Diode array detector A silicon chip that accommodates numerous photodiodes provides the capability to collect data from entire spectral regions simultaneously. Usually contains 64 to 4096 photodiodes arranged linearly. 

The performance characteristics of four optoelectronic image detectors (OIDs) are discussed. The detectors discussed are the silicon intensified target vidicon (SIT), the intensified SIT, the intensified silicon photodiode array detector (ISPD), and the self-scanned photodiode array detector. The main objective of the paper is to provide research workers interested in applying OIDs to a particular application with comparative performance information so that the best detector for a particular application may be selected. 

MCP/SPD (ISPP-Inten8ified Silicon Photodiode Array Detector)... 

Figure 3. Dark charge pattern of a preselected silicon photodiode array (Reticon RL-512SF). Note that the first 20 diodes of this particular device have significantly higher dark levels. Detector conditions (Princeton Instruments, Inc. model IRY-512) temperature, -20°C and integration time, 50 s.

Limited comparisons are also drawn for silicon intensified target vidicons (SIT) and intensified self-scanning photodiode array detectors (ISPD). 

SPD) and draw comparisons to PMT arrays as used in classical pol-ychromators. To a lesser extent, some comparisons are drawn with silicon intensified target vidicons (SIT) and intensified selfcanning photodiode array detectors (ISPD). A similar evaluation of the SPD for spectrophotometry and spectrofluorometry was recently published elsewhere (41). 

We employ method B to study effects of this type. In this mode, our apparatus yields relative high-resolution fluorescence spectra at different time windows after excitation of the sample by the 355 nm pulse. The spectra are acquired by the upconversion method. The upconverted fluorescence spectrum is recorded simultaneously at all monitored wavelengths by an optical multichannel analyzer. It is constructed from a poly-chromator (HR320 Instruments SA) and an intensified silicon photodiode array detector (Princeton Applied Research Model 1412). The detector is interfaced to our Cromemco computer. 

Photodiode array detectors are an offshoot of semiconductor technology. In semiconductors, impurities have been added to pure silicon to create two classes of materials. The addition of arsenic, bismuth, phosphorous, or antimony creates a pentavalent material (n-type) that is able to function as a donor of electrons. The addition of trivalent elements such as aluminium, boron, gallium, indium, etc., to silicon gives rise to the p-lypc material, in which the trivalent material is able... 

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