The Stern–Gerlach polarized ion source for the Munich MP-tandem laboratory, a bright source for unpolarized hydrogen and helium ion beams as well

Abstract

The design of our source of negatively charged, intense and brilliant DC beams of polarized hydrogen and deuterium ions was motivated by the excellent performance of the HERMES atomic beam source and the successful operation of a polarized ion source at TUNL. Deviating from their 30 K atomic beam technology we combine an 80 K atomic beam source (ABS) with subsequent ionization in an electron cyclotron resonance (ECR) plasma. In a separate unit, negative ions are obtained by successive two electron pickup from cesium in a vapour jet target. Our ABS provides a flux of 6.4 × 10 16 atoms / s for hydrogen and of about 5 × 10 16 atoms / s for deuterium into a compression tube of 10 mm diameter and 100 mm length. Polarized negative D - ⇒ / H - ⇒ ion beams of about 9 μ A / 15 μ A with an emittance of 20 π mm rad eV have been observed. After tandem acceleration we have polarized beam intensity of 2 μ A on target of the Q3D spectrograph. The measured vector polarizations of the D ⇒ and H ⇒ ion beams are 72% and 67%, respectively, in accordance with expectations from source operation data. Using an external gas inlet for the ECR region, intense beams of unpolarized 1 H - , 2 D - , 3 He - , and 4 He - ions are obtained.