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End Stations for Gas Phase Studies
Multiplex Coincidence Apparatus for Chemical Dynamics and Spectroscopy
 
Contact : Kaidee Lee, ext. 7313, lee@nsrrc.org.tw

  Research areas
A picture of the core section
of the endstation
A 3-D drawing of the full endstation
  Gas phase photofragmentation dynamics, photoionization, Auger and Coster-Kronig decay
   
  Research interests
  Energetics and decay paths of multiply ionized and highly excited molecules and intricate details of their dissociation dynamics and potential energy surfaces, with an eye to their potential application in controlled reactions driven by designer laser pulses.
  Selective bond breakage with core-electron excitation
Dynamics of photoionization, and Auger and Coster-Kronig electron emission, as probed by anisotropy of ejected electrons.
   
  Measuring techniques
  Electron-ion coincidence with ion imaging, electron-electron coincidence, XPS, AES, XANES, ZEKE electron spectroscopy.
   
  Capabilities
  Momentum coincidence between fragment ions aimed at revelation of the minutiae of dissociation dynamics and the topography of the potential energy surfaces.
  Rotation of the whole apparatus with respect to the light axis without breaking vacuum; facility for magic angle, pseudo-magic angle, pan-magic angle, and anisotropy measurements.
 

Ion optics capable of high mass and momentum resolution, and 4π steradian collection of ions up to 20 eV intrinsic kinetic energy, under low extraction fields suitable for coincidence measurement.

     
  Equipment list  
  Hemispherical energy analyzer (PHI, OmniV lens, 16 channel detector)
  Time-of-flight spectrometer (1 meter, real-time 2D position-sensitive detector)
     
  ZEKE electron detector  
 
CAMAC modules: TDC, G&D generator, discriminator/latch, counter, D/A converter, timing pulse generator, crate controller, PC interface card
NIM modules: TAC, differential amplifier, constant fraction discriminator, linear/logic fanout, discriminator, level translator, counter/timer, ratemeter, V/F converter
  Personal computers, power supplies, digitizing oscilloscope (Tektronix TDS 744A)
 
Pumps : Magnetically levitated turbomolecular pumps, scroll pumps, rotary vane pump