L. Lehmann

Neutron-proton charge exchange scattering between 190 MeV and 590 MeV

Abstract Differential cross sections of the np charge exchange scattering between 190 MeV and 590 MeV have been measured by detecting the scattered protons in an angular range of 0 ° ⩽ θ lab ⩽ 18 ° . The cross section at 0 ° as well as the logarithmic slope of the angular distribution are found to be almost energy independent, in contrast to previous experiments, but in agreement with recent LAMPF data.

Production of positive pions by neutron-proton collisions

Spectra of positive pions from the processn+p→π++n+n have been measured for incident neutron energies from 470 MeV to 590 MeV and for laboratory angles up to 20°. The rather broad pion energy spectra and the pronounced anisotropy of the differential cross sections, both indicate an appreciable non-resonant, isoscalar (T=0) contribution to the pion production.

Total neutron-nucleus cross sections at intermediate energies

Abstract Total neutron cross sections have been measured for the nuclei Be, C, O, Al, V, Mn, Co, Cu, Ag, Ce, Ta, Pb, Bi and U at 22 energies from 160 MeV to 575 MeV by the transmission method. The energy region contains the threshold for pion production. Different parametrizations of the experimental results are discussed. A test of charge symmetry was obtained from the proton- and neutron-induced cross sections on C and O, yielding 〈 (σ p − σ n ) σ p 〉 = 0.0012 ± 0.0059 .

Study of the reaction n + d → 3He + π− from 400 to 580 MeV☆

Differential cross sections of the reaction n + d → 3He + π− have been measured for pion emission angles 100° < θcmπ < 180° in the energy range 400 < Tn < 580 MeV. Slightly increasing angular distributions towards backward emission have been found at all energies.

Application of drift chambers in the SIN neutron beam charged particle spectrometer

Abstract Three drift chambers of the double sense-wire type totalling 240 wires, together with the CAMAC oriented Heidelberg read-out system are described with respect to the spectroscopy of pions and light nuclei ( ifA = 1−4) at the SIN neutron beam facility.

Angular distribution of the reaction np → dπ0☆

Abstract Differential cross sections of the reaction np → d π 0 have been measured for incident neutron energies between 470 MeV and 590 MeV. The angular distributions are fitted by a power series. A significant cos 4 θ contribution is found.

Multiply charged heavy ions from a standard 5.5 MV Van de Graaff

Abstract The standard equipment of the High Voltage Engineering Pulse Terminal of the 5.5 MV Van de Graaff has been used for the production of multiply charged 12 C and 20 Ne ions up to 16.5 MeV.

A NEW METHOD FOR RANGE MEASUREMENTS OF VERY HEAVY IONS USING COULOMB EXCITATION AND PERTURBED ANGULAR CORRELATION.

Abstract A method is proposed for the measurement of range and range straggling of very heavy ions in any stopping material. The usual radiochemical detection is completely avoided. A range measurement of 0.8 MeV tungsten ions in copper has been carried out in order to demonstrate the method. The measured range is in good agreement with the theory of Lindhard, Scharff and Schiott.