High density polarized hydrogen/deuterium internal target

We present a high-density polarized hydrogen/deuterium internal gas target. The apparatus is based on a setup that was previously used in electron sca ttering experiments with tenser-polarized deuterium [1]. The target was upg raded by implementing state-of-the-art permanent sextupole magnets in the A tomic Beam Source (ABS) and by using a longer (60 cm) and colder (similar t o 70 K) cylindrical storage cell. This resulted in an increase of the targe t figure-of-merit, (polarization)(2) x luminosity, by about one order of ma gnitude. The target was used in combination with a 720 MeV polarized electr on beam stored in the AmPS ring (NIKHEF) to measure spin observables in ele ctron-proton and electron-deuteron scattering. Scattered electrons were det ected in a large acceptance magnetic spectrometer. Ejected hadrons were det ected in a single time-of-flight scintillator array. The product of beam an d target polarization was determined from the known e'p (quasi) elastic asy mmetry. We achieved a target thickness of 1.1 x 10(14) atoms/cm(2) with typ ical beam currents of 110 mA, which corresponds to a luminosity of about 7. 5 x 10(31) cm(-2) s(-1) Target and beam polarizations up to 0.7 and 0.65 re spectively were obtained.