An investigation of the Omegatron type mass spectrometer

• Main Author: Martel, Hardy Cross
• Format: Others
• Published: 1956
• Online Access: https://thesis.library.caltech.edu/2490/1/Martel_hc_1956.pdf; Martel, Hardy Cross (1956) An investigation of the Omegatron type mass spectrometer. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/71EX-5M05. https://resolver.caltech.edu/CaltechETD:etd-06072004-153528 <https://resolver.caltech.edu/CaltechETD:etd-06072004-153528>

An Omegatron type mass spectrometer has been investigated both theoretically and experimentally to determine its detailed operation and limitations. Resolution, peak height, shape and frequency have been calculated theoretically and compared experimentally. A method is given for sketching ion trajectories in the nonlinear case (e.g., with space charge). Using this method, it is shown that a small amount of space charge will seriously hamper the operation of the Omegatron in that it will limit the maximum excursion of a resonant ion and thus limit the possible resolution. It is shown that under normal operating conditions a trapping voltage is necessary to maintain ion collection efficiency, and that this trapping voltage causes a space charge sufficient in size to result in nonlinear ion trajectories and poor operation. It is concluded that in order to get good operation of the Omegatron some method will have to be found for eliminating the space charge or its effects. Several possibilities for doing this are suggested, the most intriguing one being to use a dipole type of RF electric field rather then a uniform one.