Internal gas targets in AmPS

For polarized deuterium one has the ability to reverse the tensor polarization at fixed vector polarization and vice versa. Subsequently, small systematic errors can be expected. This technique is currently exploited at the Amsterdam Pulse Stretcher storage ring at NIKHEF, where ultrapure polarized hydrogen, deuterium, and ³He targets are available. In this presentation, we want to discuss the implications of the use of gas targets for the vacuum in the storage ring, and the strategy that was used at NIKHEF to optimize the luminosity by balancing between the conflicting requirements of dense gas targets and high electron beam life time. The polarized internal gas targets are briefly described. The implementation of the gas targets in the vacuum system of the ring is discussed