International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators

4-8 May 2009, Vienna

H^- Ion Source with Inverse Gas Magnetron Geometry for SNS Project

V.A. Baturin, P.A. Litvinov, and S.A. Pustovoitov

Institute of Appliad Physics, National Academy of Sciences of Ukraine, Sumy, Ukraine

Corresponding Author: baturin49@gmail.com

At the Institute of Applied Physics of National Academy of Sciences of Ukraine the plasma dualchamber source of H^- ions having a rapid starting, reliable and long-time operation and also simplicity in service was designed for the injector of a high energy accelerator. In more details design of this source can be found in reference [1]. It is a non-cesium ion source working on the basis of tubular discharge. For plasma generation the inverse gas magnetron is used. The dual-chamber design of a source allows receiving rather easily necessary vacuum conditions, using pumps with average speeds of pumping.

In plasma volume of non-cesium H^- ion source the conditions for obtaining of increased density of H^- ions in the field of adjoining to the emission aperture were realized. It was made due to increase of flow of slow electrons to plasma adjoining to the emission aperture and their retention in this volume, and also due to decrease of gas pressure in an accelerating interval of a source.

The value of density of H^- emission current 440 mA/cm² is obtained. The designed source has high operating characteristics. It has rapid starting. The current of H^- ions with nominal parameters is usually reached in 1 - 2 minutes after achievement of necessary vacuum conditions and supply of high voltage.

In the paper the results of optimization of emission and optical properties of the ion source will be presented. Earlier version of non-cesium source worked in the structure of RFQ accelerator for a long time. Adding cesium to an uncesiated source promises an increased H^- current output with a reduced beam emittance. Therefore, the paper also examines cesiated version of the source. H^- ion source represented in the paper can be used as an alternative version of injector for the Spallation Neutron Source accelerator complex, presently under construction at Oak Ridge National Laboratory.

[1] Yu.V. Kursanov, P.A. Litvinov, V.A. Baturin, H^- Source with the Volume-Plasma Formation of Ions AIP Conference Proceedings 763, American Institute of Physics (2005) pp. 229-234.

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