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In the study of parity violation by the scattering of longitudinally polarized spin 1 2 particles, systematic errors arise from the presence of small polarization components perpendicular to the beam. A quantitative treatment of these errors is presented. It is shown that non-uniform polarization distributions over the beam profile give sizeable effects even if the average transverse polarization vanishes. Methods are presented which permit accurate correction of the parity measurements for the presence of transverse polarization components. It is shown that the necessary information can be obtained by measuring four suitably chosen one-dimensional intensity and polarization distributions within the beam. Finally, possible origins of the non-uniform polarization distributions are outlined.

The pC analyzing power has been measured for laboratory scattering angles between 5° and 20° at 299, 380, 483 and 561 MeV proton kinetic energy. The experiment was performed at SIN using a carbon analyzer sandwiched between multiwire proportional chamber telescopes placed directly in a polarized beam. Some effects of inelasticity have been investigated.

An experimental program on proton-proton scattering is presently running at SIN. This article gives technical details of the instruments and equipment employed. It reviews, in particular, the SIN polarized proton beam, the large scale equipment, the LH2 and the polarized targets, the detectors, the electronics, the on-line computer and the different basic layouts. Possibly this material could be split into separated articles. However, we find it more valuable to present here a complete picture which reflects the “state of the art”.

A beam profile monitor is described which permits a rapid quantitative determination of the beam intensity profiles I(x), I(y) in two directions (x, y) perpendicular to the beam, as well as the proton beam-polarization profiles Py(x), Py(y), Px(y) and Px(x) for a 50 MeV proton beam. The device consists of two wheels which move thin strips of graphite through the beam. Four scintillation detectors are used to detect protons elastically scattered from the graphite targets. An encoder digitizes the position of the targets associated with each detected proton. The scanner is interfaced with a computer. Performance figures for the scanner are given. Typically, when a 0.1 μA beam of 3 mm diameter is interrupted by the targets during 10% of the time, a 1 min measurement suffices to determine the center of the beam to ±4 μm and the beam polarization to ±0.3%.

A set of p-p scattering measurements which allows the p-p scattering matrix to be determined directly from experiment at given energies and angles is proposed and discussed. Present day experimental techniques are taken into consideration. The scattering matrix is determined independently of phase shift analyses and can be used to check the reliability of their predictions. Estimates of the precision needed in this complete experiment and the corresponding uncertainties in the scattering amplitudes are given.