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SUMMARY:X-rays and light from diffuse mechanical energy - Jonathan Hird\, 
 Department of Physics & Astronomy\, University of California at Los Angele
 s\, USA
DTSTART:20121122T160000Z
DTEND:20121122T170000Z
UID:TALK38447@talks.cam.ac.uk
CONTACT:Stephen Walley
DESCRIPTION:Triboelectrification is the amazing process whereby surfaces a
 cquire large charge densities as a result of being brought into contact or
  fractured. The phenomenon is considered a hazard in many industrial situa
 tions since electric fields of 1 MV cm-1 can be realised simply by bringin
 g two surfaces in-and-out of contact. There is no ab initio theory of trib
 oelectrification\, yet an Edisonian approach to the subject has yielded us
 eful devices such as those for xerography. For hazard mitigation\, a list 
 of materials known as the triboelectric series serves as a useful engineer
 ing benchmark to determine material compatibility\, but the charge entity 
 responsible for the process–be it an ion or electron–is still disputed
 . We have discovered that if triboelectrification is carried out in a mode
 rate vacuum environment X-rays are produced with sufficient flux and energ
 y to image a human digit in a few seconds. In this talk\, I will introduce
  the subject of triboelectrification\, describe how the emitted X-rays may
  give insight into the processes that cause electrical charging and will d
 iscuss potential applications and uses of this intriguing phenomenon.
LOCATION:Mott Seminar Room\, Cavendish Laboratory\, Department of Physics
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