Phys.Rev.Lett.89:052302,2002 The analyzing power for proton-carbon elastic scattering in the
coulomb-nuclear interference region of momentum transfer,
$9.0\times10^{-3}<-t<4.1\times10^{-2}$ ...(GeV/$c)^{2}$, was measured with a 21.7
GeV/$c$ polarized proton beam at the Alternating Gradient Synchrotron of
Brookhaven National Laboratory. The ratio of hadronic spin-flip to non-flip
amplitude, $r_5$, was obtained from the analyzing power to be $\text{Re}
r_5=0.088\pm 0.058$ and $\text{Im} r_5=-0.161\pm 0.226$.
Polarized protons were injected and accelerated in the clockwise ring of RHIC to commission the first full helical Siberian snake ever used in an accelerator. With the snake turned on, the stable ...spin direction is in the horizontal plane. Vertically polarized protons were injected with the snake off. The snake was adiabatically ramped to give a spin rotation of 180/spl deg/ around a horizontal rotation axis about 13/spl deg/ from the longitudinal. When the beam was accelerated from injection G/spl gamma/ = 46.5 to G/spl gamma/ = 48 the spin flipped sign as expected and polarization was preserved. At G/spl gamma/ = 48 without the snake, no polarization was observed since several spin resonances were crossed. Eventually polarized beam was accelerated to G/spl gamma/ = 55.7 (29.1 GeV). In the next proton running period we plan to run with two full helical snakes in each ring and collide both transversely and longitudinally polarized protons at an energy around 100 GeV per beam.
A p-carbon CNI polarimeter for RHIC Huang, H.; Bai, M.; Bunce, G. ...
Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366),
1999, Letnik:
1
Conference Proceeding
Odprti dostop
The RHIC spin program requires excellent polarimetry so that the knowledge of the beam polarization does not limit the errors on the experimental measurements. However, polarimetry of proton beams ...with energies higher than about 30 GeV poses a difficult challenge. For polarization monitoring during operation, a fast and reliable polarimeter is required that produces a polarization measurement with a 10% relative error within a few minutes. The p-carbon elastic scattering in the Coulomb-nuclear-scattering (CNI) region has a calculable and large analyzing power, but detecting the recoil carbon needs a sophisticated detector system and a very thin target. An experiment has been planned in the AGS. This paper describes the experimental setup in the AGS.
The analyzing power for proton-carbon elastic scattering in the coulomb-nuclear interference region of momentum transfer, \(9.0\times10^{-3}<-t<4.1\times10^{-2}\) (GeV/\(c)^{2}\), was measured with a ...21.7 GeV/\(c\) polarized proton beam at the Alternating Gradient Synchrotron of Brookhaven National Laboratory. The ratio of hadronic spin-flip to non-flip amplitude, \(r_5\), was obtained from the analyzing power to be \(\text{Re} r_5=0.088\pm 0.058\) and \(\text{Im} r_5=-0.161\pm 0.226\).
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