Detector overload protection

Fig. 7.41 Components for detector overload protection HFAC-26 preamplifier, DCC-lOO detector controller card, and shutter assembly for R3809U MCP. Becker Hickl, Berlin...

In primary size reduction, more particularly with big single-stage coarse crushers, operational reliability is best achieved by very heavy and robust design of these machines, equipped with mechanically or hydraulically operated overload protection devices to prevent damage being caused by foreign bodies that cannot be crushed. On the other hand, secondary crushers which are fed with pre-crushed rock below about 300 mm particle size can be effectively protected by magnetic separators by metal detectors. 

The detectors, especially MCP-PMTs, can be severely overloaded by daylight leaking into the detection path. Moreover, the halogen or mercury lamp of the microscope may be a source of detector damage. Therefore, an NDD FLIM system must protect the detectors from overload. Detector protection by suitably controlled shutters is described under Sect. 7.3, page 302. 

The strongest argument is that a properly designed preamplifier ean be used to protect the detector against overload. The principle is shown in Fig. 7.38. 

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