ZIROX Vacuum Probe Properties Main part of the ZIROX vacuum probe is a potentiometric zirconia solid electrolyte cell. Due to the several oxygen partial pressures (inside and outside the vacuum recipient), a voltage occurs between measuring and reference electrode. This voltage is proportional to the logarithm of the oxygen partial pressures. From the cell voltage, the oxygen partial pressure at the measuring electrode can be calculated according to the NERNST equation. The connection head contains the electronics for heating control and signal processing and the membrane pump for the reference gas supply. In contrast to the ZIROX normal pressure probes, the vacuum probe is not calibration-free. The reason are the special sensor heater (inside the probe tube) and several conditions at the measuring electrode (energy removal depends on gas pressure and thermal conductivity). Therefore, isothermal electrodes cannot be provided for the correct use of the NERnSt equation. For process control, however, the use of empirically determined values is mostly sufficient. For measuring oxygen partial pressures, the user must calibrate the probe (test measurements). Under normal pressure the probe voltage, determined in a stationary state (ambient air), can be subtracted as constant offset. Applications The ZIROX vacuum probe serves the determination of oxygen partial pressures in vacuum applications. Typical examples are measurements in vacuum processes (PVD, CVD or other plasma processes), in surface treatment applications as well as for measurements in material science. ZIROX Vacuum Probe

6 mm, with protection tube 16 mm 0…400 mV or 0…1200 mV (range switchover on circuit board) Plug assignment (Type 423 6pol., Fa. Binder, Best.-Nr.: 99-5622-15-06): 1 2 Ready contact (potential-free)