產品名稱：Denka LaB6 Filaments

The relative drawbacks of tungsten cathodes are a work function of 4.7eV, insufficient beam current, and a short service life. LaB₆ has a work function of 2.66eV – thus more easily emitting electrons – and is a relatively stable material, so it has been increasingly used as a material for cathodes instead of tungsten. Using LaB₆ cathodes with TEM’s and SEM’s, even with the electron beam narrowed down, it is possible to obtain enough beam current to achieve better resolution and clear micrographs with less noise. The principle advantage, however, is that LaB₆ can be used in a stable condition for a much longer time. Denka manufactures the purest, highest quality LaB₆ crystals for use in their cathode tips.

Benefits

• High Brightness: A LaB₆ beam is 10 times brighter than tungsten, has superior resolution, and features a wide range of acceleration voltages. It provides sharp, clear pictures, down to the smallest detail. The initial brightness of a Denka Model 3 cathode (1 x 10⁶A/cm².Str) is substantially better than that of competing, mini-vogel type cathodes (typically 5 x 10⁵A/cm².Str).
• Long Life: Heat and vacuum are the final determinants of any cathode tip’s life, but at 1550°C and a vacuum of 10-7 Torr, a service life of about 500 hours can be expected.
• Stability: Thanks to its simple and durable construction, every Denka Model 3 LaB₆ Cathode offers a stability of better than 3% per hour at 1550°C.
• Interchangeability: Denka Model 3 LaB₆ cathodes are designed as direct replacements for tungsten filaments when a vacuum in the 10^-7 range is provided.
  

  Comparison of Tip Configurations Available with Denka M-3 LaB6 AEI style Cathodes
  	Flat Tip	Standard (Round) Tip	Sharp Tip
  	90° or 60° cone angle 20/40/60/100µm flat tip radius	90° cone angle 15µm tip radius	60° cone angle 5µm and 10µm tip radius
  Brightness	About 5 times that of tungsten 2-5 x 105 A/cm2 • Str	About 10 times that of Tungsten 1 x 106 A/cm2 • Str	Twice as bright as standard tips 2 x 106 A/cm2 • Str
  Saturation	Mono spot at about 1,400°C	Mono spot at about 1,500°C	Almost the same as standard tips
  Crossover	Large (11-13µm)	Small (7-10µm)	Small (7-10µm)
  Angular Distribution	Broad 3.3-4.2 x 10-2rad	Sharp 1.6 x 10-2rad	Sharp 1.6 x 10-2rad
  Used Temperature	Low Temperature	High Temperature	High Temperature
  Lifetime	Long life (usable at low temperatures, and crystallized end changes slowly)	Long life; shorter than flat tips	Short
  Operation	Easy (thanks to its large spot size and broad adjusting range)	Not so difficult	Difficult (the point adjustment needed)
  Stability	High (invulnerable to thermal expansion or vibration)	High	Middle (vulnerable to thermal expansion or vibration, adjustment is sometimes necessary)
  Technology Needed	Ordinary	High	Very High

  Denka M-3 LaB₆ Cathode for JEOL Instruments

  Prod #	Description	Unit

  1450

  Denka M-3 LaB6, JEOL Cathode

  each

  Denka M-3 LaB₆ Cathode for FEI, Philips Instruments (Except XL-30)

  Prod #	Description	Unit

  1451

  Denka M-3 LaB6, FEI Philips Cathode

  each

  Denka M-3 LaB₆ Cathode for AMRAY Instruments
  (except 1200 Series)

  Prod #	Description	Unit

  1452

  Denka M-3 LaB6, AMRAY Cathode

  each

  Denka M-3 LaB₆ Cathode for Cambridge (except S2A and S4-10), Camscan, Electroscan
  Leica, LEO and Zeiss (EVO^®) Instruments

  Prod #	Description	Unit

  1453

  Denka M-3 LaB6, Cambridge Cathode

  each

  Denka M-3 LaB₆ Cathode for Hitachi Instruments

  Prod #	Description	Unit

  1454

  Denka M-3 LaB6, Hitachi Cathode

  each