| paraxial rays | In geometric optics, those ray's focused at the principal point. (05 Mar 2000) |
|---|---|
| cathode rays | A stream of electrons emitted from the negative electrode (cathode) in a Crookes tube; their bombardment of the anode or the glass wall of the tube gives rise to X-ray's. (05 Mar 2000) |
| glass rays | Those formed by cathode ray's striking the wall of an X-ray tube. (05 Mar 2000) |
| cephalometric X-rays | <dentistry> An X-ray of the head that shows whether your teeth are aligned properly, and whether they are growing properly. (08 Jan 1998) |
| monochromatic rays | Light ray's or ionizing radiation of a very narrow band of wavelengths (ideally, of a single wavelength). Compare: photopeak, characteristic radiation. (05 Mar 2000) |
| W rays | Those between ultraviolet and X-ray's. Synonym: W rays. (05 Mar 2000) |
| cosmic rays | <radiobiology> High velocity particles of enormous energies, bombarding earth from outer space. It consists of protons and more complex atomic nuclei that, on striking the atmosphere, give rise to neutrons, mesons, and other less energetic radiation. (05 Mar 2000) |
| positive rays | Those originating in a gas discharge tube and moving in a direction opposite to that of cathode ray's; made up of positively charged ions. Synonym: positive rays. (05 Mar 2000) |
| hard rays | Ray's of short wavelength and great penetrability. (05 Mar 2000) |
| primary rays | Cosmic ray's in the form in which they first strike the atmosphere, X-ray's generated at the focal spot of the tube. Synonym: direct rays. (05 Mar 2000) |
| X-rays | Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release energy - in the same energy range as gamma rays (0.010-10 mev), but of non-nuclear origin, of shorter wavelength than ultraviolet; soft X-rays or grenz rays are less penetrating and longer in wavelength than hard X-rays. (12 Dec 1998) |
| secondary rays | X-ray's generated when primary X-ray's impinge upon matter; scattered radiation. (05 Mar 2000) |
| H rays | <physics> A stream of hydrogen nuclei; i.e., protons. (05 Mar 2000) |
| soft rays | X-ray's of relatively long wavelength and slight penetrability. (05 Mar 2000) |
| Niewenglowski rays | Radiation emitted from a phosphorescent body after exposure to sunlight. (05 Mar 2000) |