W.A. Dezarn

Performance of a polarized-hydrogen storage cell target

Abstract A storage cell has been constructed for use as an internal polarized gas target in the storage ring at the Indiana University Cyclotron Facility. The storage cell has thin teflon walls which allow for detection of low energy recoil particles. We report on nuclear polarization measurements of hydrogen atoms, produced by an atomic beam source, in this storage cell. The results indicate that a target polarization in excess of 0.70 is achieved. We discuss the design and construction details of a storage cell target and the polarization results which are based on low-energy pp spin correlation measurements using the University of Wisconsin tandem accelerator.

Polarized internal gas target for hydrogen and deuterium at the IUCF Cooler Ring

Abstract A polarized internal gas target has been constructed and used at the IUCF Cooler Ring. Polarized hydrogen atoms produced by a high-intensity atomic beam source are injected into a target cell whose Teflon walls are thin enough to allow low-energy recoil particles to be detected in coincidence with forward scattered particles. An average proton target polarization of 0.740±0.013 has been measured.

Interaction of stored, cooled proton beams with fiber targets

Abstract The use of thin fibers as internal targets for nuclear physics experiments in storage rings is discussed. We have measured the lifetime and the energy spread of stored, electron-cooled beams in the presence of an internal carbon fiber target. Measurements have been carried out in the Indiana Cooler with proton beams between 100 MeV and 300 MeV. The effect of the inhomogeneous fiber target on the beam is the same as that of a homogeneous gas target of equivalent thickness within the accuracy of the measurement. The measurements are compared with a Monte Carlo simulation of the stored beam. It is demonstrated that charging of the fiber target can significantly affect the lifetime and energy spread of the stored beam.

Thin Teflon film walls for a polarized-gas target cell☆

Abstract Immersion coating, spray coating, stretching, and roll-reduction methods have been explored in work to produce pinhole-free films of Teflon that are 5 cm × 30 cm in area and less than 500 μg/cm 2 thick. A method to produce these films by rolling thicker, commerically available films will be described. The defining characteristics and limitations encountered with each of the other preparation methods also are presented. Four of the self-supporting Teflon films form the walls of an open-ended cell used to increase the density of a polarized-hydrogen target [M.A. Ross et al., Nucl. Instr. and Meth. A 344 (1994) 307; W.A. Dezarn et al., these Proceedings (17th World Conf. of the INTDS, Bloomington, IN, USA, 1994) Nucl. Instr. and Meth. A 362 (1995) 36]. At a wall thickness of 500 μg/cm 2 , roughly half the thickness of commerically available film, detection of recoil protons became possible.

Polarized internal gas target for hydrogen and deuterium at the IUCF cooler ring

A polarized internal H gas storage cell target has been successfully operated in the IUCF cooler ring. A target thickness for atomic hydrogen has been measured to be 3.5±0.3×1013/cm2 in a single spin state. Target polarization (0.75±0.01) showed no sign of deterioration after two weeks of operation with an average beam current of 100 μA. Detection of p‐p elastic events at 200 MeV bombarding energy has been demonstrated by use of coincidences between silicon detectors near the beam and a forward detector array. This target is presently being used to measure p‐p elastic scattering spin correlation coefficients at 200 MeV.