Limitations: Serious injury is possible if people cannot escape from the beam; skin burns within minutes.
限制：如果人们不躲避光束严重的受伤是可能的，数分钟内皮肤会烧伤。
2
The intensity of the secondary radiations is weak compared with the intensity of the primary X-ray beam, and some of it, too, may not escape from the material.
这些次级放射线的强度跟原始x射线相比较弱，而且其中的一部分可能留在了那种物质中。
3
Based on the photoelectric effect, when a beam of monochromatized radiation is shined on a sample, electrons are emitted and escape to the vacuum (Fig. 1).