Electron Time-of-Flight Spectrometers

ETF11 Electron Time-of-Flight Spectrometer

• Minimum electron energy ca. 20 eV (depending on the magnetic fields of the environment)
  
• Time-of-flight resolution T/ΔT = ca. 100
• Fieldfree drift tube with 350 mm standard length, encapsulated in a µ-metal shield
• Drift tube region can be floated to positive or negative potentials:
  up to –180 V for decelerating fast electrons
  up to +180 V for accelerating slow electrons to reduce the effect of magnetic fields
  Channelplate detector with two-stage chevron geometry, channelplates with 5 µm pore size for fast response times, 40 mm active diameter
• Post-acceleration stage in front of the detector to get a uniform sensitivity for all electrons irrespective of their kinetic energy and to reduce the effects of magnetic fields penetrating through the back flange into the µ-metal shield
• Conical entrance aperture with 3 mm diameter, the distance between the entrance aperture and the laser focus is also 3 mm. The distance between the tof connection flange and the laser focus is 354 mm (standard)
• Only completely non-magnetic materials are used for the spectrometer, most of the parts including the drift tube and all screws are made from titanium
• The electron beam entering through the entrance aperture is collimated in an extraction module, the acceptance angle (full angle) is ca. 45°. The only connection between the ionisation chamber and the tof chamber is the entrance aperture which allows to pump the tof spectrometer differentially
• The vacuum chamber of the electron spectrometer is manufactured from non-magnetic stainless steel 1.4429 (equivalent to 316 LN). It consists of a 6” o.d. conflat (CF100) connection flange, a 6” o.d. conflat (CF100) pump flange (CF100) and a 2.75” o.d. conflat flange (CF38) for pressure metering
• High voltage power supply in a 19” box, 3HE (132 mm) high, 350 mm deep

• Drift tube length other than standard length of 350 mm
• Distance between tof connection flange and laser focus other than standard length of 354 mm
• Accelerating/decelerating voltages different from standard values of +180V / -180 V, different maximal lens voltage

ETF15 Combined Electron TOF / Positive Ion Mass Spectrometer

• The bipolar setup allows to use the spectrometer either as a electron tof spectrometer with time-of-flight resolution T/ΔT > 100 or as a sensitive time-of-flight mass spectrometer with mass resolution M/ΔM > 300
  
• Minimum electron energy ca. 20 eV (depending on the magnetic fields of the environment)
• Fieldfree drift tube with ca. 350 mm standard length, encapsulated in a µ-metal shield
• In “electron mode” the drift tube can be floated to positive or negative potentials:
  up to –180 V for decelerating fast electrons
  up to +180 V for accelerating slow electrons to reduce the effect of magnetic fields
• Channelplate detector with two-stage chevron geometry, channelplates with 5 µm pore size for fast response times, 40 mm active diameter
• Post-acceleration stage in front of the detector to get a uniform sensitivity for all electrons irrespective of their kinetic energy and to reduce the effects of magnetic fields penetrating through the back flange into the µ-metal shield
• Only completely non-magnetic materials are used for the spectrometer, most of the parts including the drift tube and all screws are made from titanium
• The electron beam entering through the entrance aperture is collimated in an extraction module, the acceptance angle (full angle) is ca. 30°. The only connection between the ionisation chamber and the tof chamber is the entrance aperture which allows to pump the tof spectrometer differentially
• The vacuum chamber of the electron spectrometer is manufactured from non-magnetic stainless steel 1.4429 (equivalent to 316 LN). It consists of a 6” o.d. conflat (CF100) connection flange, a 6” o.d. conflat (CF100) pump flange (CF100) and a 2.75” o.d. conflat flange (CF38) for pressure metering
• High voltage power supply in a 19” box, 3HE (132 mm) high, 500 mm deep. All the polarities of the high voltages are reversed with a single switch

• Drift tube length other than standard length of 350 mm
• Distance between tof connection flange and laser focus other than standard length of 354 mm

ETF20 High Energy Electron Time-of-Flight Spectrometer

• The ETF20 electron tof spectrometer is optimized for electron energies > 1000 eV. Conventional electron tof spectrometers (like our model ETF11) are difficult to operate in the high energy range because the time-of-flights can get very short (< 10 ns). The ETF20 spectrometer allows to decelerate the electrons by a factor of up to 100.
• When deceleration is used only a section of the kinetic energy spectrum can be analysed because electrons with energies smaller than the deceleration potential (i.e. drift tube potential) cannot reach the detector
• Maximal deceleration voltage (drift tube potential) is -2 kV
  
• The divergence of the electron beam caused by the their deceleration is compensated with a deceleration module consisting of several electron-optical elements. The maximal acceptance angle of the ETF20 spectrometer is 6° (full cone, size of ionization zone < 200 µm)
• Minimum electron pass energy ca. 20 eV (depending on the magnetic fields of the environment
• Detector is floating on the drift tube potential
• The fieldfree drift zone after deceleration has a length of ca. 430 mm
• The distance laser focus – entrance aperture is 25 mm, the distance laser focus – connection flange is 354 mm.
• Channelplate detector with two-stage chevron geometry, channelplates with 5 µm pore size for fast response times, 40 mm active diameter
• The vacuum chamber of the electron spectrometer is manufactured from non-magnetic stainless steel 1.4429 (equivalent to 316 LN). It consists of a 6” o.d. conflat (CF100)connection flange, a 6” o.d. conflat (CF100) pump flange (CF100) and a 2.75” o.d. conflat flange (CF38) for pressure metering
• High voltage power supply in a 19” box, 3HE (132 mm) high, 350 mm deep. The voltages can be adjusted either with 10-turn potentiometers or via control voltages 0 - 10 V from a DA-converter