| any device used to prevent ions in an electron beam from striking other apparatus, esp. in mass spectrometry. |
| ion trap n. A device, such as a magnet, used to prevent ions in an electron beam from striking other apparatus. |
| ion trap
A device, such as a magnet, used to prevent ions in an electron beam from striking another apparatus, such as a cathode-ray tube screen, which could cause it to lose luminescence. |