Miniature PMTs in TO-8 Housing

The metal-channel design of the R5600 and R7400 results in slight periodical variations of the efficiency and the IRF over the active area, see Fig. 6.41. Consequently, either the entire active area should be illuminated or the position of the illuminated spot should be kept stable. Variations in the position can be a pitfall in TCSPC scanning applications (see Fig. 5.93, page 158). 

A typical correlation function of the afterpulses is shown in Fig. 6.38. The afterpulsing probability is relatively high, especially for the NIR-sensitive versions. The afterpulsing ceases after one microsecond and can, as usual, be reduced by operating the tube at reduced gain. 

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