High density polarized hydrogen gas target for storage rings

Abstract

A target of gaseous polarized hydrogen was formed by injecting polarized hydrogen atoms (produced by Stern–Gerlach spin separation) into a storage cell consisting of a cylindrical tube open at both ends. The target was placed in a storage ring to study the target characteristics (nuclear polarization, target thickness, radiation resistance). A weak transverse guide field (5 G) was applied to define the polarization direction. When atoms in a single hyperfine state were selected, the nuclear polarization of the target was measured to be 0.80±0.02. The areal density of the target under these conditions was (5.5±0.2)×1013 H/cm2, while for two spin states (applicable to experiments in high energy rings where a strong magnetic field can be applied to the target) the target thickness was found to be (8.2±0.3)×1013 H/cm2. The target polarization was unaffected by prolonged exposure of the target to beams up to 1 mA.

Toward polarized antiprotons: Machine development for spin-filtering experiments

“…When the polarization lifetime is by several orders of magnitude longer than the spin filtering periods required, it becomes feasible to polarize an originally unpolarized beam by filtering, as was confirmed in a dedicated experiment [28], described in section IX. 9…”

“…The polarized internal target (PIT) consists of the atomic beam source (ABS), which was developed for the TSR spin-filtering experiment [9,50], later used in the HERMES experiment at DESY [51,52] and now modified for spin-filtering at COSY, a storage cell [53], a Breit-Rabi polarimeter (BRP) [54], and a target gas an- alyzer (TGA) [55]. H 0 atoms in a single hyperfine state are prepared in the ABS and injected into a thin-walled storage cell.…”

Pulsed‐Laser Production and Detection of Spin‐Polarized Hydrogen Atoms

“…For W' = À1, all the signs are reversed [Equation (5) However, the prompt dissociation may also proceed nonadiabatically, via a mechanism that involves an H atom spin flip. This occurs either through the a 3 P 1 state, which yields products in their electronic ground states, or through a second pathway, which leads to electronically (spin-orbit) excited Cl( 2 P 1/2 ) [henceforth referred to also as Cl*; see Equations (6) and (7) If either the spin-down channel [Equation (5)] or the spin-up channel [Equations (6) and (7)] dominates, then SPH will be produced. The degree of nascent SPH produced by the photodissociation must be probed before secondary collisions can cause relaxation, preferably using pulsed-laser detection.…”

“…However, the optical production or direct detection of spin-polarized hydrogen (SPH) atoms has proven to be very difficult. Polarized nuclei can be produced effectively by the Stern-Gerlach separation, [6] which consists of passing a collimated atomic beam through an inhomogeneous magnetic field (Figure 1) that separates the beam according to the projection M of the atomic angular momentum J along the z axis. The polarization purity attainable using this technique can be as high as 100 %.…”

Highly Spin-Polarized Atoms and Molecules from Rotationally State-Selected Molecules

“…Important applications include the study of spin-dependent effects in atomic and nuclear collisions [1], the elucidation of molecular structure and dynamics using NMR [2], and quantum computation [3,4]. Methods for producing polarized atoms include Stern-Gerlach separation [5], optical pumping [6], and spin-exchange optical pumping [1], whereas spin-polarized molecules have been produced by spin exchange [7]. In this Letter we show how nuclear polarizations of up to 100% may be produced using optical techniques.…”