Using Static Charge on Pyroelectric Crystals to Produce Self Focusing   Electron and Ion Beams and Transport Through Tubes
  Static charge in and on the surface of pyroelectric crystals of LiNbO3 and LiTaO3 in a dilute gas has been shown to ionize gas molecules via electron tunneling. The released electrons and positive ions are focused and accelerated according to the sign of the static uncompensated charge. The uncompensated charge is produced when the temperature of the crystal is changed from any initial temperature between about 500K and about 15K. It may be either polarization charge that is inside the crystal surface or compensation charge that is on the surface. The direction of temperature change and the polarity of the base of the crystal determine whether electrons or positive ions are accelerated toward or away from the crystal. The ionization, focusing and acceleration may continue for more than 15 days following a single change in temperature. 
James D. Brownridge and Stephen M. Shafroth