A 70 keV neutral hydrogen beam injector with energy recovery for an MSE diagnostic application in fusion research

• Published in: PACS2001. Proceedings of the 2001 Particle Accelerator Conference (Cat. No.01CH37268) Vol. 4; pp. 2533 - 2535 vol.4
• Main Authors: Simonin, A., Armitano, A., Brugnetti, R., Cano, V., Dougnac, H., Fazilleau, P.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 2001
• Subjects: Current density; Current measurement; Hydrogen; Particle beam injection; Particle beam measurements; Particle beams; Plasma confinement; Plasma diagnostics; Plasma measurements; Stark effect
• ISBN: 9780780371910; 0780371917
• DOI: 10.1109/PAC.2001.987821

A 70 keV 40 A hydrogen beam injector has been developed at Cadarache for a plasma diagnostic (MSE: Motional Stark Effect) to provide a measurement of the plasma current distribution in the Tore-Supra Tokamak. We present in this paper, the principle and the first experimental results of the injector, where a new type, and advantageous, energy recovery system, based on a magnetic neutraliser plasma confinement, has been developed. The hydrogen ion beam is accelerated to 70 keV with a three-grid multi-aperture system (aperture diameter /spl Phi/=11 mm) with an ion current density of /spl ap/160 mA/cm/sup 2/. An ion source with a shape (height 1.2 m, width 80 mm) specifically adapted to the recovery system has been developed to meet the injector requirements: uniformity, high proton fraction (>80%) and high current density, /spl ap/160 mA/cm/sup 2/ over the whole extraction surface (900 cm/sup 2/). A neutral beam power (H/sup 0/) of 500 kW has been achieved with a divergence of /spl ap/0.6/spl deg/ at 70 keV.