1. Measuring apparatus and measuring systems for detecting ionising radiation, in particular alpha, beta, gamma, neutron and X-radiation

2. The ionosphere, like the atmosphere and its ozone layer, protects humans from disastrous (at large doses) ultraviolet and X-radiation.

3. The ionosphere, like the atmosphere and its ozone layer, protects humans from disastrous (at large doses) ultraviolet and X-radiation

4. Airglow, faint luminescence of Earth’s upper atmosphere that is caused by air molecules’ and atoms’ selective absorption of solar ultraviolet and X-radiation

5. Object.-The intensity of general x-radiation is known to be approximately proportional to the atomic weight of the element constituting the Anticathode, provided the other conditions are the same

6. X-ray tube, oscillatory sparks being excluded; and thus the Anticathode is brought to send an X-radiation of extremely short duration through the gas before the lenses of a stereoscopic camera.

7. Characteristic and General X-Radiation.-From a comparison of (a) the radiation from different Anticathodes, and (b) the intensity as measured by ionization and by the photoelectric effect, it is inferred that the radiation is largely general.

8. This distinction was reinforced by Charles Barkla (1877–1944) in 1907: superimposed on the spectrally-spread out x-radiation from electron impacts (Bremsstrahlung) was a series of sharp strong peaks characteristic of the anti-cathode metal (fluorescent x-rays) that Barkla showed were polarized