[en] The elastic and inelastic scattering of positive and negative pions from ⁷Li was investigated at 164 MeV. Angular distributions were measured between 27 and 93⁰. The ratios of the π^-/π⁺ cross sections were determined for several states. 6 references

[en] Excitation functions have been measured for the elastic, recoil, and alpha-particle exit channels for four reactions: ¹⁷O+¹²C (E/sub lab/ = 30.0--57.0 MeV), ¹⁶O+¹³C (E/sub lab/ = 29.5--52.6 MeV), ¹⁷O+¹³C (E/sub lab/ = 30.0--57.0 MeV), and ¹⁶O+¹⁰B (E/sub lab/ = 42.4--60.1 MeV). The alpha particles were detected at theta/sub lab/ = 10⁰ while the elastic and recoil particles were detected at theta/sub lab/ = 34⁰. Statistical analyses of the data are used to search for correlated, nonstatistical structures in the excitation functions. The resonant properties of three compound nuclei (²⁶Al, /sup 29,30/Si) are studied by comparing the excitation energies at which nonstatistical structures are seen when the nuclei are formed via different well matched (in terms of J/sub max/) entrance channels. These resonancelike structures seen in the various entrance channels (for a given compound nucleus) are found to be uncorrelated in excitation energy, thereby implying a dependence upon the properties of the entrance channel. The lack of entrance channel correlations and the short lifetimes of the structures seen are viewed as evidence that the reaction may proceed through a quasimolecule, or that the compound nucleus itself is so highly excited and deformed that its formation is entrance channel dependent

[en] The exit channels for elastic and alpha particles have been detected for ¹⁴N bombardment on ¹²C over the energy range E/sub lab/ = 45.0--60.0 MeV. Extensive statistical analyses of the data show evidence for nonstatistical structure (or ''resonances''). Some of these structures are correlated in the two exit channels, especially one prominent structure at E/sub c.m./ = 22.4 MeV. The reaction mechanism is discussed, and all the evidence is consistent with a quasimolecular resonance formed by the ¹⁴N and ¹²C entrance channel nuclei

[en] A new type of Extensive Air Shower (EAS) array is proposed which is based on the measurement of individual cosmic ray tracks and muon identification. Air showers can be detected in the range from 10¹²eV up to the highest energies. The direction of the primary γ-ray will be reconstructed with accuracies typically in the range of 0.1deg to 0.3deg. The sensitivity for the detection of point sources will be improved by about a factor of 100 in comparison to existing conventional EAS arrays or Atmospheric Cerenkov Telescopes. (orig.)

[en] Published in summary form only

[en] The authors present preliminary results for π⁺-¹⁶O elastic scattering at 79, 114, 163, 240 and 343 MeV. Statistical uncertainties are about 5% for angular bins of 1.5⁰. The data are compared to a first-order momentum-space optical model calculation. (Auth.)

[en] The CRT (Cosmic Ray Tracking) project proposes a new type of extensive air shower (EAS)-array. About 400 drift chambers of the TPC type will allow the tracking of individual shower electrons. This results in an angular resolution for air showers of σ_θ<0.3deg. In combination with a low energy threshold of a few 10¹² eV the angular measurement can be calibrated absolutely by observing the cosmic ray shadow of the moon. We present the design and construction of the first full size detector module and report on the results of detailed tests of a half size prototype. (orig.)

[en] The CRT (cosmic ray tracking) project proposes a new type of extensive air shower (EAS) array. 384 drift chambers of the TPC type will allow the tracking of individual shower electrons. This results in an angular resolution for air showers of σ_θ<0.3deg. In combination with a low energy threshold of a few 10¹² eV the angular measurement can be calibrated absolutely by observing the cosmic ray shadow of the moon. Results of detailed tests of several prototype drift chambers are reported. (orig.)

[en] Recently the interest of astronomers and high energy physicists has focussed again on cosmic rays, in particular on high energy γ-rays. The CRT (cosmic ray tracking) project proposes a new type of extensive air shower array. A large number of drift chambers on the TPC type will allow the tracking of individual shower electrons. This results in an angular resolution for air showers of σ_θ<0.3deg, even near the energy threshold of a few 10¹² eV. The design and construction of the detector modules is described. These modules determine tracks in space inside a cylindrical volume of 1.8 m diameter and 0.75 m height with an accuracy of about one millimeter. With a half-scale prototype detector particle distributions in air showers triggered by a scintillator array were measured. (orig.)

[en] The importance of pion inelastic scattering in investigating the isospin composition of nuclear forces is well known. Although other projectiles are useful in determining various other excitations, the ratios of sigma(π^-)/sigma(π⁺) for inelastic scattering provide sensitive tests of the understanding of the isospin structure. Recently several predictions have been made of the ratio R=sigma(π^-)/sigma(π⁺) for the 0⁺₁ - 2⁺₁ transition in ²⁶Mg. Surprisingly a ratio less than one, R=0.7, is predicted indicating that the proton components are larger. However, the shell-model calculations of Brown and Wildenthal predict for the 0⁺₁ - 2⁺₂ transition a ratio of R=1.9 which is 2.5 times what they predict for the 0⁺₁ - 2⁺₁ transition. Therefore, the 0⁺₁ - 2⁺₂ transition is predicted to be dominated by neutron excitation. Since shell-model calculations are presently well developed and sophisticated, it is important to test these new calculations. The authors have measured the angular distributions of π^+- scattered from ²⁶Mg at 180 MeV, and obtained a value for R(0⁺₁-2⁺₁) of 0.68+-0.09 in good agreement with the predictions. (Auth.)