Author/Authors :
Airapetian، نويسنده , , A. and Akopov، نويسنده , , N. and Akopov، نويسنده , , Z. and Amarian، نويسنده , , M. and Andrus، نويسنده , , A. and Aschenauer، نويسنده , , E.C. and Augustyniak، نويسنده , , W. and Avakian، نويسنده , , R. and Avetissian، نويسنده , , A. and Avetissian، نويسنده , , E. and Bailey، نويسنده , , P. and Balin، نويسنده , , Beverley D. and Baumgarten، نويسنده , , C. and Beckmann، نويسنده , , M. and Belostotski، نويسنده , , S.، نويسنده ,
Abstract :
The HERMES hydrogen and deuterium nuclear-polarized gas targets have been in use since 1996 with the polarized electron beam of HERA at DESY to study the spin structure of the nucleon. Polarized atoms from a Stern–Gerlach Atomic Beam Source are injected into a storage cell internal to the HERA electron ring. Atoms diffusing from the center of the storage cell into a side tube are analyzed to determine the atomic fraction and the atomic polarizations. The atoms have a nuclear polarization, the axis of which is defined by an external magnetic holding field. The holding field was longitudinal during 1996–2000, and was changed to transverse in 2001. The design of the target is described, the method for analyzing the target polarization is outlined, and the performance of the target in the various running periods is presented.
Keywords :
Spin polarized hydrogen , Deuterium , Detection of atomic beams , Polarized targets , Internal target , Atomic beam source , Polarimeters
