CYCLOTRONS 2010 - List of Authors (Goswami, A.)

Paper	Title	Page
MOPCP038	Design Optimization of the Spiral Inflector for a High Current Compact Cyclotron	129
	A. Goswami, V.S. Pandit, P. Sing Babu DAE/VECC, Calcutta, India
	VECC is developing a 10 MeV, 5 mA compact proton cyclotron. 80 keV protons from a 2.45 GHz microwave ion source will be injected axially in the central region by a spiral inflector. Because of the high injection energy, the inflector will be comparatively large in size. In order to avoid the beam blow up due to space charge effect and to accommodate the inflector in the small available space in the central region, the design and optimization of the inflector parameters require special attention. This paper describes the design of the spiral inflector and studies its optical properties in the presence of space charge. The beam trajectory calculation from the entrance of the spiral inflector to the central region of the cyclotron have been carried out using the magnetic field data obtained from a 3D code and the electric field data from RELAX3D. We have also checked the orbit centering of the injected beam using a central region code. We have evaluated the effect of linear space charge and carried out optimization of the input beam parameters to minimize the coupling effects between two transverse planes at the inflector exit and to match the acceptance of the central region.

MOPCP079	Optimization of Sector Geometry of a Compact Cyclotron by Random Search Method	212
	P. Sing Babu, A. Goswami, V.S. Pandit, P.R. Sarma DAE/VECC, Calcutta, India
	A compact four sector 10 MeV, 5 mA proton cyclotron is being developed at VECC, Kolkata. Proton beam at 80keV from a 2.45 GHz ion source (under testing) will be first collimated and bunched and will be injected axially in the central region where a spiral inflector will place the beam on the orbit. This paper describes the procedure of optimizing the sector geometry of the magnet to obtain the desired isochronous field. Due to fringe field effect, analytical formulae do not predict the correct sector shape particularly at the lower radii in the cases of compact cyclotrons, where hill gap is very small and valley gap is large. Hence a 3D code becomes necessary to obtain the correct shape and size of the magnet sectors. This involves a lengthy iterative procedure of determining the hill angle at a large number of radii. In our procedure magnet sector is described in terms of a small number of parameters which are iteratively determined by random search technique geared to minimize the frequency error. 3D magnetic field data and results of equilibrium orbit code are used as input to the code developed for the optimization.

Paper

Title

Page

Design Optimization of the Spiral Inflector for a High Current Compact Cyclotron

129

A. Goswami, V.S. Pandit, P. Sing Babu
DAE/VECC, Calcutta, India

VECC is developing a 10 MeV, 5 mA compact proton cyclotron. 80 keV protons from a 2.45 GHz microwave ion source will be injected axially in the central region by a spiral inflector. Because of the high injection energy, the inflector will be comparatively large in size. In order to avoid the beam blow up due to space charge effect and to accommodate the inflector in the small available space in the central region, the design and optimization of the inflector parameters require special attention. This paper describes the design of the spiral inflector and studies its optical properties in the presence of space charge. The beam trajectory calculation from the entrance of the spiral inflector to the central region of the cyclotron have been carried out using the magnetic field data obtained from a 3D code and the electric field data from RELAX3D. We have also checked the orbit centering of the injected beam using a central region code. We have evaluated the effect of linear space charge and carried out optimization of the input beam parameters to minimize the coupling effects between two transverse planes at the inflector exit and to match the acceptance of the central region.

MOPCP079

Optimization of Sector Geometry of a Compact Cyclotron by Random Search Method

212

P. Sing Babu, A. Goswami, V.S. Pandit, P.R. Sarma
DAE/VECC, Calcutta, India

A compact four sector 10 MeV, 5 mA proton cyclotron is being developed at VECC, Kolkata. Proton beam at 80keV from a 2.45 GHz ion source (under testing) will be first collimated and bunched and will be injected axially in the central region where a spiral inflector will place the beam on the orbit. This paper describes the procedure of optimizing the sector geometry of the magnet to obtain the desired isochronous field. Due to fringe field effect, analytical formulae do not predict the correct sector shape particularly at the lower radii in the cases of compact cyclotrons, where hill gap is very small and valley gap is large. Hence a 3D code becomes necessary to obtain the correct shape and size of the magnet sectors. This involves a lengthy iterative procedure of determining the hill angle at a large number of radii. In our procedure magnet sector is described in terms of a small number of parameters which are iteratively determined by random search technique geared to minimize the frequency error. 3D magnetic field data and results of equilibrium orbit code are used as input to the code developed for the optimization.