JACoW is a publisher in Geneva, Switzerland that publishes the proceedings of accelerator conferences held around the world by an international collaboration of editors.
@inproceedings{wong:ecris2020-tuzzo06, author = {C.Y. Wong and S.M. Lund}, title = {{Beams with Three-Fold Rotational Symmetry: A Theoretical Study}}, booktitle = {Proc. ECRIS'20}, % booktitle = {Proc. 24th International Workshop on ECR Ion Sources (ECRIS'20)}, pages = {110--113}, eid = {TUZZO06}, language = {english}, keywords = {ECR, ion-source, solenoid, simulation, dipole}, venue = {East Lansing, MI, USA}, series = {International Workshop on ECR Ion Sources}, number = {24}, publisher = {JACoW Publishing, Geneva, Switzerland}, month = {07}, year = {2022}, issn = {2222-5692}, isbn = {978-3-95450-226-4}, doi = {10.18429/JACoW-ECRIS2020-TUZZO06}, url = {https://jacow.org/ecris2020/papers/tuzzo06.pdf}, abstract = {{Beams from ECR ion sources have 3-fold transverse rotational symmetry induced by the ECR sextupole. The symmetry imposes equality constraints among transverse beam moments, which can be derived using a theoretical framework we developed. Since the constraints are solely a consequence of the rotational symmetry of external fields, they hold for a multi-species beam with arbitrary composition and space charge intensity. These constraints provide a new tool to analyze phase space properties of ECR beams and their impact on low-energy transport. We prove that, regardless of their triangulated spatial density profile, beams with 3-fold rotational symmetry have the same RMS emittance and Twiss parameters along any transverse direction. These counter-intuitive results are applied to the FRIB Front End to show how symmetry arguments challenge long-standing assumptions and bring clarity to the beam dynamics.}}, }