Yinlong Lu

Ion source and low energy injection line for a central region model cyclotron

At CIAE, a 100 MeV H(-) cyclotron (CYCIAE-100) is under design and construction. A central region model (CRM) cyclotron was built for various experimental verifications for the CYCIAE-100 project and for research and development of high current injection to accelerate milliampere H(-) beam. The H(-) multicusp source built in 2003 has been improved recently to make the source operation more stable. A new injection line for axial low energy high current injection has been designed and constructed for the CRM cyclotron.

Development of Specially Designed Small Doublet for Compact Cyclotron Beam Injection

A number of compact cyclotrons accelerating H- ions to energies between 10 MeV and 100 MeV have recently been constructed for research and medical diagnostics/therapy in several countries. However limitations in extracted beam intensity are brought up by inadequate injection efficiency from the ion source into the machine. To improve the optics matching from the external source to machine acceptance, a specially designed small doublet has been developed to replace the traditionally used solenoid in the vertical injection line before the spiral inflector. Due to the narrow space inside the compact cyclotron, the doublet is designed based on the following special consideration: 1) To use the central plug of the main magnet as a part of the return yoke of the doublet; 2) To use the capillary water-cooling conductor for the coil to keep the doublet sufficiently small; 3) To adopt an integral design of the two quadrupoles into one assembly so that they could be installed in the channel of the central plug in high vacuum environment. In this paper, the design of the doublet is introduced. The outer diameter of 118 mm is precisely fit to the central plug of the Verification Facility of High Intensity Cyclotron at CIAE. Its inner diameter is 50 mm for beam injection. It can provide a maximal magnetic field gradient of 2.6 T/m from the measurement. Various kinds of detailed techniques for the doublet fabrication, e.g. the enwinding of capillary water-cooling conductor with outer diameter of 3 mm and inner diameter of 2 mm, the poles and yoke assembling, will be presented. The beam test results will be given as well.

Construction Status of Main Magnet for CYCIAE-100

A new radioactive ion beam project, Beijing Radioactive Ion-beam Facility (BRIF), has been started at CIAE since 2004 . In this project, a 100 MeV H- cyclotron, CYCIAE-100, is selected as the driving accelerator providing 75-100 MeV, 200-500 proton beam. CYCIAE-100 is consisting of the main magnet, RF system, ion source and injection system, dual beam extraction system, etc. The progress of this machine had been reported elsewhere . The main magnet is the most critical part and had been numerically simulated and delicately designed . The techniques for main magnet construction are investigated in detail . The construction of this compact style, 450 ton cyclotron magnet has been started since 2007. The imperfection control of the large scale casting steel, the deformation and fabrication tolerance, etc., have all posed a challenge to the capacity limitation of cyclotron lab at CIAE for magnet design, mapping and shimming, and of industry for steel production/machining in the world. The design highlight of the magnet will be briefly introduced and the emphasis in this paper will be given to the construction progress.

Matching from H− multicusp source to central region of a 100MeV compact cyclotron for high current injectiona)

The way of matching the beam from an external ion source to the central region of the cyclotron CYCIAE-100 is presented in this article. The transverse acceptances of the central region were calculated, which provided the matching ellipse parameter requirements to the injection transport optics design. The optics of the injection line was simulated using TRANSOPTR, which allowed space charge effect calculation, and neutralization was taken into account.