Abstract
Longitudinal and vertical focusing with a field gradient spiral inflector
Highlights
Introduced by Belmont and Pabot in 1966, traditional spiral inflectors are used to inject external axial beams into the midplane of a cyclotron
In the Solid Pole Cyclotron 2 (SPC2) at iThemba LABS, numerical modeling of the vertical motion produced by the Belmont-Pabot inflector
In spiral inflectors initial transverse displacements at the inflector entrance can result in final longitudinal displacements: ðljxÞ; ðljx0Þ; ðljyÞ; ðljy0Þ ≠ 0. This has the effect of longitudinally elongating a bunch of particles that all arrive at the inflector at the same time, thereby producing a debunching effect. This effect is very significant and TOSCA [7] models of the traditional spiral inflector used at iThemba LABS show a Æ39° rf phase spread when injected with a typical beam of 90π mm mrad transverse emittance and no momentum spread
Summary
Introduced by Belmont and Pabot in 1966, traditional spiral inflectors are used to inject external axial beams into the midplane of a cyclotron. At iThemba LABS a new inflector was developed that utilized angled electrodes and edge effects to obtain very good vertical focusing, resulting in an experimentally measured 100% improvement in the extracted current from the cyclotron, whenever the buncher was not used [6] This inflector introduced an unwanted longitudinal spread, which greatly decreased its time-dependent performance, so that the improvement in transmission dropped to around 20% when the buncher was activated. This has the effect of longitudinally elongating a bunch of particles that all arrive at the inflector at the same time, thereby producing a debunching effect This effect is very significant and TOSCA [7] models of the traditional spiral inflector used at iThemba LABS show a Æ39° rf phase spread when injected with a typical beam of 90π mm mrad transverse emittance and no momentum spread. This shows that an inflector should ideally focus both longitudinally and vertically at the same time
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
