Toward polarized antiprotons: Machine development for spin-filtering experiments

Abstract

The paper describes the commissioning of the experimental equipment and the machine studies required for the first spin-filtering experiment with protons at a beam kinetic energy of 49.3MeV in COSY. The implementation of a low-β insertion made it possible to achieve beam lifetimes of τb=8000s in the presence of a dense polarized hydrogen storage-cell target of areal density dt=(5.5±0.2)×1013atoms/cm2. The developed techniques can be directly applied to antiproton machines and allow for the determination of the spin-dependent p¯p cross sections via spin filtering

Electromagnetic Simulation and Design of a Novel Waveguide RF Wien Filter for Electric Dipole Moment Measurements of Protons and Deuterons

“…Within the COSY ring, the PAX low-β section [10] offers the possibility to vary the beam size by about a factor of three, therefore the RF Wien filter will be installed at this location.…”

“…The mesh accuracy in the xy plane amounts to 0.1 mm and 11 mm in z-direction. The phase-space distribution of the beam at the entry of the RF Wien filter is known [10]. The phase space is expressed in terms of positions x and y, and transverse angles x ′ = v x /v z and y ′ = v y /v z .…”

The legacy of the experimental hadron physics programme at COSY

“…Several ABS systems have been used at COSY, including those at EDDA [37], ANKE [41], and PAX [42]. These are technologically very complex devices and the interested reader is directed to these references.…”

“…As at Heidelberg, this was fed from an atomic beam source but the target polarization was controlled much more precisely through the inclusion of a Breit-Rabi polarimeter. The electron cooler was used to compensate for multiple small-angle Coulomb scattering and the energy loss in the target and the residual gas in the machine [42]. The beam polarization was measured in the other straight section of COSY using the ANKE facility, which does not seriously affect the beam quality.…”

Computational framework for particle and spin simulations based on the stochastic Galerkin method

“…At the location of COSY, where the device is installed, the beam size is adjustable by modifying the β-function to values between about β = 0.4 and 4 m [24]. In this paper, we consider only the case when β = 0.4, and a typical initial phase-space ellipse for a well-cooled beam at the entrance of the RF Wien filter at z = 1 mm are shown in panel (a) of [1].…”