Linearity & Errors

List of Systematic Errors in Current Measurement

• Unser Monitor Current Measurement:
  This error depends on the intensity of the current at which the calibration has been done:
  absolute error = 250nA --> relative error = 0.25/calibration current.
  For example the error will be 1% at 25µA, or 0.1% at 250µA.
  (for 1 step in the calibration = 2 minutes)
  


• Temperature dependance of the Resonnant Cavities:
  The Q factor of the cavities is temperature dependant; the temperature controller of the system keeps the temperature variations as low as 0.2°C. This leads to an error of 0.07% in the measurement.
  


• Cables Temperature dependance:
  The 10m long Heliax 7/8" cables have a temperature dependance of 0.0016dB/°C; this contributes to 0.036% if the temperature inside the Hall moves by 2°C.
  The 60m long Triaxial cables that carry the 1MHz signal have a temperature dependance of 0.0022dB/°C; this contributes to 0.045% if the temperature in the cable tray is changed by 2°C.
  


• Beam displacement:
  This effect gives about 0.06% for 1cm of radial displacement of the beam.
  


• Cross-Talk:
  We ahve observed a cross-talk of 0.1% in the 1MHz cables; however the fluctuation in this cross-talk has never been measured, but we can assume it is negligeable.