An observation of a new class of afterpulses with delay time in the   range of 70-200 microseconds in classical vacuum photomultipliers
  We present results of the first observation of afterpulses with extremely long (~120 microseconds) delay time from the main pulse in 8 inch classical vacuum photomultipliers. 
R.V. Poleshchuk, B.K. Lubsandorzhiev, R.V. Vasiliev
physics.ins-det hep-ex nucl-ex