SuperKEKB is an unpolarized electron-positron collider designed for a luminosity of 8 × 1035 cm−2s−1 with a 4 GeV positron beam (Low Energy Ring - LER) and 7 GeV electron beam (High Energy Ring - HER). To enable precision measurements of the weak neutral couplings in the Belle II experiment, an upgrade is under consideration to polarize the HER to 70% by...
The $200\,\mathrm{MeV}$ polarimeter at Linac is based on the elastic proton-carbon scattering at $16.2^\circ$ angle, where the analyzing power reaches almost absolute maximum which was experimentally established with high accuracy of $99.35\pm0.15\,\%$ . The elastically and inelastically scattered protons are clearly separated by the difference in the propagation through adjustable thickness...
For the Electron-Ion Collider, a polarized ${}^3\mathrm{He}^{++}$ ion source is being constructed at the Electron Beam Ionization Source (EBIS) of the Brookhaven National Laboratory. For precision determination of the ${}^3\mathrm{He}$ polarization, the ${}^3\mathrm{He}$ beam, after acceleration to 6 MeV at EBIS, will be elastically scattered off a gas ${}^4\mathrm{He}$ target. For such a...
A possibility to precisely measure absolute vertical polarization of the EIC ${}^3\mathrm{He}$ beams using the polarized hydrogen gas jet target (HJET) is discussed. By concurrent measurement of $a_h$ and $a_p$, the beam $h^\uparrow p$ and jet $p^\uparrow h$ spin asymmetries for the detected recoil protons, the He3 beam polarization can be approximated by $P_\mathrm{beam}=P_\mathrm{jet}\times...
Polarization of high energy proton beams has successfully been measured at RHIC with elastic proton-proton and proton-Carbon scattering. The analyzing power is not known from first principles and has to be measured.
The observed background to the elastic scattering events needs to be much better understood because of the much shorter bunch spacing at EIC. This background can cause a simple...
Peripheral scattering of polarized proton, deuteron, and Helium-3 ions on light nuclei, and other nuclei, provides a method of evaluating the level of polarization of high energy beams. The asymmetry of recoils resulting from elastic collision can indicate the analyzing power required for polarimetry provided a number of quantities are known with sufficient accuracy.
Among the items needed...
The PHENIX collaboration has observed a large azimuthal asymmetry
of forward neutrons produced in polarized pA collisions. The data
are well described by a model incorporating photons from the high Z
nucleus photoproducing low mass baryonic states from the polarized
proton. The model is based on well known electromagnetic effects and
well measured photoproduction processes.
We will...
High-Precision 5 MeV Mott Polarimetry at CEBAF+
T.J.Gay*
University of Nebraska - Lincoln
We report on the design and performance of a Mott polarimeter optimized for a nominal 5-MeV electron beam from the CEBAF injector. The rf time structure of this beam allows the use of time-of-flight in the electron detection, making it possible to isolate those detected electrons that originate from...
