Faraday Cage for Probe Current Measurement in EMs - Practical Electron Microscopy and Database - - An Online Book - |
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Microanalysis | EM Book https://www.globalsino.com/EM/ | ||||||||
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Probe currents in TEM and SEM systems can be measured with a picoammeter at the large phosphorus viewing screen or the small phosphorus viewing screen, and at the sample with a faraday cup holder. The electron probe (beam) current can be directly and simply measured with a Faraday cage. Therefore, the currents obtained at the Faraday cup can be the currents used for dose calculations. For instance, in some TEM cases, the Faraday cages are mounted on a removable specimen rod. The current measurement can be done as follows: Figure 3115. Faraday cage used to measure electron beam currents: (a) Calibration of zero current. (b) Beam current measurement.
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