Meaurement of atomic beam parameters

Several techniques used for the experimental determination of parameters characterizing atomic hydrogen beams like intensity, density, velocity, optical properties, degree of dissociation are critically analysed and possible source of large systematic errors in the use of different measuring devices are discussed. In this resume, only intensity and density measurements are commented. While compression tubes and mass spectrometers have proven to be reliable instruments for optimization work where relative measurements are sufficient, their use for the determination of absolute values is a much more delicate undertaking, where difficulty is often underestimated. Large systematic or scale errors may have their origin in a variety of non-obvious effects modifying the sensitivity of the devices or affecting the accuracy of the calibration procedures