Ch. Weddigen

Proton-carbon analyzing power between 300 and 560 MeV☆

Abstract 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.

Pion production by the reaction p + p → π+ + d using polarized beam and target

Abstract The information to be obtained from differential cross section measurements on the reaction p + p → π + + d using a polarized beam and target is discussed. Up to now this reaction has been investigated only with an unpolarized target. The experimental knowledge on the reaction is briefly reviewed. Expressions are given for the differential cross section, using also polarized target, and information to be obtained on production amplitudes is discussed. For proton lab energies up to 1 GeV only pion partial s-, p- and d-waves are supposed to be effective. The seven kinematically permissible production amplitudes can be fully determined from differential cross section measurements using a polarized beam and target if only two deuteron vector polarizations without a polarized target are determined in addition. Some solid-angle restrictions for “usual” dynamically polarized targets are discussed.

A quantitative monitor for beam intensity and polarization profiles

Abstract 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%.

Measurement of the spin correlation parameter A00nn and the polarization A00n0 in elastic p-p scattering between 400 and 600 MeV

Abstract We have measured the spin correlation parameter A 00 nn and the polarization A 00 n 0 for p-p elastic scattering in the c.m. angular range between 30° and 90° at seven energies between 400 and 600 MeV. The experiment was performed at SIN using a polarized beam and target and a fast on-line event reconstruction method. The results are compared with phase-shift predictions.

Eine experimentelle anordnung zur durchführung von doppel- und einfachstreuexperimenten bei mittleren energien

Abstract An experimental set-up is described for double and single scattering experiments which has been installed at the Karlsruhe isochronous cyclotron (52 MeV deutrons and 104 MeV α-particles). Primary and secondary scattering angles can be easily changed during an experiment. A quadrupole triplet serves to collect the particles from the first to the second target. A special monitor system for the secondary beam allows effective alignments within ±0.02°. Pure semiconductor and combined semiconductor scintillation telescopes allow for particle identification. The primary energy can be varied by water cooled absorbers. The apparatus has been used for differential cross section and polarization measurements involving spin 0-, 1 2 - and 1 - particles.

An experimental ensemble used for the study of proton-proton scattering at SIN

Abstract 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 LH 2 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 Complete Experiment for p p Scattering at Medium-Energies

Abstract 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.

Effects of transverse polarization components in parity tests with longitudinally polarized nucleons

Abstract 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 analysing power of the reaction pp → πd for proton energies between 500 AND 600 MeV

Abstract The analysing power A y0 of the pp → π d reaction has been measured at SIN for four energies between 516 and 582 MeV with a statistical precision of better than 1%. Pions and deuterons have been detected in coincidence with scintillation detectors employing time-of-flight techniques for event identification. Using our data on the differential cross section σ, Legendre polynomial expansion coefficients b j y0 for the product σA y0 have been deduced for j = 1 to 5. The energy dependence of these coefficients has been compared with theoretical predictions.

The spin-correlation coefficient Axz of the reaction pp → πd for proton energies between 500 and 600 MeV

Abstract The spin-correlation coefficient A xz of the pp → π d reaction has been measured at SIN for 515, 542, and 582 MeV. The SIN polarized target was viewed for d-detection by two single-arm scintillator telescopes. Time-of-flight techniques and range selection were employed to reduce the background. Using our data on the differential cross section σ and on the analysing power A y 0, the complex Legendre polynomial expansion coefficients b k = b k xz + ib k y 0 for the quantity σ ( A xz + iA y 0 ) are compared with theoretical predictions. In addition, recent predictions of partialwave analyses are compared with our results on A xz