CYCLOTRONS2022 - List of Keywords (hadrontherapy)

Paper	Title	Other Keywords	Page
THAO01	On the Energy Limit of Compact Isochronous Cyclotrons	cyclotron, resonance, focusing, hadron	255
	W.J.G.M. Kleeven IBA, Louvain-la-Neuve, Belgium
	Existing analytical models for transverse beam dynamics in isochronous cyclotrons are often not valid or not precise for relativistic energies. The main difficulty in developing such models lies in the fact that cross-terms between derivatives of the average magnetic field and the azimuthally varying components cannot be neglected at higher energies. Taking such cross-terms rigorously into account results in an even larger number of terms that need to be included in the equations. In this paper, a method is developed which is relativistically correct and which provides results that are practical and easy to use. We derive new formulas, graphs, and tables for the radial and vertical tunes in terms of the flutter, its radial derivatives, the spiral angle and the relativistic gamma. Using this method, we study the 2nur=N structural resonance (N is number of sectors) and provide formulas and graphs for its stopband. Combining those equations with the new equation for the vertical tune, we find the stability zone and the energy limit of compact isochronous cyclotrons for any value of N. We confront the new analytical method with closed orbit simulations of the IBA C400 cyclotron for hadron therapy.
	Slides THAO01 [6.641 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-CYCLOTRONS2022-THAO01
About •	Received ※ 22 December 2022 — Revised ※ 05 February 2023 — Accepted ※ 07 February 2023 — Issue date ※ 02 April 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPO009	Vacuum Model of the C400 Cyclotron for Hadrontherapy	vacuum, cyclotron, injection, extraction	317
	V. Nuttens, P. Cailliau, Q. Flandroy, W.J.G.M. Kleeven, J. Mandrillon IBA, Louvain-la-Neuve, Belgium Ph. Velten NHa, Caen, France
	Since 2020, NHa and IBA collaborate on the development of the C400 cyclotron dedicated to hadron therapy. This machine accelerates C⁶⁺ and He²⁺ up to 400 MeV/n and H²⁺ up to 260 MeV/n. The H²⁺ is extracted by stripping and the other particles by electrostatic extraction. Vacuum management in the injection line and in the cyclotron are of prime importance to avoid large beam losses. Indeed, C⁶⁺ ions are subjected to charge exchange during collision with the residual gas. On the opposite, H²⁺ will suffer from molecular binding break up. According to cross section data, the constraints on the residual gas pressure is driven by C⁶⁺ in the injection line and by H²⁺ in the cyclotron. An electrical equivalent model of the vacuum system of the cyclotron, its injection and extraction lines has been developed in LTSpice® software to determine the pressure along the particle path. Contributions from outgassing surfaces, O-ring outgassing and permeation are included and vacuum pump requirement could be obtained. The expected beam transmission is then evaluated based on cross sections available from the literature.
	Poster THPO009 [0.524 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-CYCLOTRONS2022-THPO009
About •	Received ※ 06 December 2022 — Revised ※ 12 January 2023 — Accepted ※ 31 January 2023 — Issue date ※ 14 March 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

THAO01

On the Energy Limit of Compact Isochronous Cyclotrons

cyclotron, resonance, focusing, hadron

255

W.J.G.M. Kleeven
IBA, Louvain-la-Neuve, Belgium

Existing analytical models for transverse beam dynamics in isochronous cyclotrons are often not valid or not precise for relativistic energies. The main difficulty in developing such models lies in the fact that cross-terms between derivatives of the average magnetic field and the azimuthally varying components cannot be neglected at higher energies. Taking such cross-terms rigorously into account results in an even larger number of terms that need to be included in the equations. In this paper, a method is developed which is relativistically correct and which provides results that are practical and easy to use. We derive new formulas, graphs, and tables for the radial and vertical tunes in terms of the flutter, its radial derivatives, the spiral angle and the relativistic gamma. Using this method, we study the 2nur=N structural resonance (N is number of sectors) and provide formulas and graphs for its stopband. Combining those equations with the new equation for the vertical tune, we find the stability zone and the energy limit of compact isochronous cyclotrons for any value of N. We confront the new analytical method with closed orbit simulations of the IBA C400 cyclotron for hadron therapy.

Slides THAO01 [6.641 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-CYCLOTRONS2022-THAO01

About •

Received ※ 22 December 2022 — Revised ※ 05 February 2023 — Accepted ※ 07 February 2023 — Issue date ※ 02 April 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPO009

Vacuum Model of the C400 Cyclotron for Hadrontherapy

vacuum, cyclotron, injection, extraction

317

V. Nuttens, P. Cailliau, Q. Flandroy, W.J.G.M. Kleeven, J. Mandrillon
IBA, Louvain-la-Neuve, Belgium
Ph. Velten
NHa, Caen, France

Since 2020, NHa and IBA collaborate on the development of the C400 cyclotron dedicated to hadron therapy. This machine accelerates C⁶⁺ and He²⁺ up to 400 MeV/n and H²⁺ up to 260 MeV/n. The H²⁺ is extracted by stripping and the other particles by electrostatic extraction. Vacuum management in the injection line and in the cyclotron are of prime importance to avoid large beam losses. Indeed, C⁶⁺ ions are subjected to charge exchange during collision with the residual gas. On the opposite, H²⁺ will suffer from molecular binding break up. According to cross section data, the constraints on the residual gas pressure is driven by C⁶⁺ in the injection line and by H²⁺ in the cyclotron. An electrical equivalent model of the vacuum system of the cyclotron, its injection and extraction lines has been developed in LTSpice® software to determine the pressure along the particle path. Contributions from outgassing surfaces, O-ring outgassing and permeation are included and vacuum pump requirement could be obtained. The expected beam transmission is then evaluated based on cross sections available from the literature.

Poster THPO009 [0.524 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-CYCLOTRONS2022-THPO009

About •

Received ※ 06 December 2022 — Revised ※ 12 January 2023 — Accepted ※ 31 January 2023 — Issue date ※ 14 March 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)