Incident beam voltage

Scattering Angle (Relative to Incident Beam) Voltage... 

Fig. 6.3 Simulation of the interaction between incident electrons and the sample, as a function of incident beam voltage, by Monte Carlo calculation of the electron trajectories [49]. The volume is much less at low beam voltages. (From Joy and Pawley [49] reproduced with permission.)...

Fig. 6.8 Total electron yield as a function of the incident beam voltage. When the yield is less than one, the sample charges negatively. When it is greater than one, the sample charges positively. This makes E2 (and zero) a stable point with no further charging.

This unit sufficed to account for the occurrence of all spots observed on several Laue photographs taken with a tube operated at a peak voltage of 54 kv. (the incident beam making small angles with [100] or [110]), and may be accepted as the true unit. 

A transmission Laue pattern is made of an aluminum crystal with a specimen-to-film distance of 5 cm. The (111) planes of the crystal make an angle of 3° with the incident beam. What minimum tube voltage is required to produce a 111 reflection ... 

There is a fundamental difference between the operation of a powder camera and a diffractometer. In a camera, all diffraction lines are recorded simultaneously, and variations in the intensity of the incident x-ray beam during the exposure can have no effect on relative line intensities. On the other hand, with a diffractometer, diffraction lines are recorded one after the other, and it is therefore imperative to keep the incident-beam intensity constant when relative line intensities must be measured accurately. Since the usual variations in line voltage are quite appreciable, the x-ray tube circuit of a diffractometer must include a voltage stabilizer and a tube-current stabilizer. 

The linearity of the photodiode detector was checked using neutral density filters and over the range of operation the output voltages are proportional to the incident beam... 

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