▁High - techn ologies , ▁F E I ▁Company , ▁and ▁N ION . ▁ ▁Ult raf ast ▁and ▁Dynamic ▁T EM ▁It ▁is ▁possible ▁to ▁reach ▁temporal ▁resolution ▁far ▁beyond ▁that ▁of ▁the ▁read out ▁rate ▁of ▁electron ▁detect ors ▁with ▁the ▁use ▁of ▁p uls ed ▁electrons . ▁P uls es ▁can ▁be ▁produced ▁by ▁either ▁modifying ▁the ▁electron ▁source ▁to ▁enable ▁las er - trigger ed ▁photo em ission ▁or ▁by ▁installation ▁of ▁an ▁ult raf ast ▁beam ▁blank er . ▁This ▁approach ▁is ▁term ed ▁ult raf ast ▁transmission ▁electron ▁micro sc opy ▁when ▁st rob os cop ic ▁p ump - pro be ▁ill um ination ▁is ▁used : ▁an ▁image ▁is ▁formed ▁by ▁the ▁accum ulation ▁of ▁many ▁electron ▁p uls es ▁with ▁a ▁fixed ▁time ▁delay ▁between ▁the ▁arrival ▁of ▁the ▁electron ▁pul se ▁and ▁the ▁sample ▁exc itation . ▁On ▁the ▁other ▁hand , ▁the ▁use ▁of ▁single ▁or ▁a ▁short ▁sequence ▁of ▁electron ▁p uls es ▁with ▁a ▁sufficient ▁number ▁of ▁electrons ▁to ▁form ▁an ▁image ▁from ▁each ▁pul se ▁is ▁called ▁dynamic ▁transmission ▁electron ▁micro sc opy . ▁Tem por al ▁resolution ▁down ▁to ▁hundreds ▁of ▁fem to seconds ▁and ▁spatial ▁resolution ▁compar able ▁to ▁that ▁available ▁with ▁a ▁Sch ott ky ▁field ▁emission ▁source ▁is ▁possible ▁in ▁ult raf ast ▁T EM , ▁but ▁the ▁technique ▁can ▁only ▁image ▁revers ible ▁processes ▁that ▁can ▁be ▁reprodu ci b ly ▁triggered ▁millions ▁of ▁times . ▁Dynamic ▁T EM ▁can ▁resolve ▁irre vers ible