[en] For future precision measurements, the uranium Hadron Calorimeter (HC) of the L3 experiment needs good calibration. The presented work deals with the cosmic ray muon calibration of the cylindrical HC Barrel. Cosmic ray muons penetrate the Muon Chambers, the Hadron Calorimeter and the Scintillation Counters. With the information from these detectors, the corresponding signals in the HC Barrel can be identified. The short signal delay between the wire chamber and the analog-to-digital(ADCs) does not allow direct triggering of the ADCs with cosmic ray muons. The changes of the ADC values, due to extended ADC gate, are reproducible and can be corrected for. The use of muons in the range from 2 to 120 GeV energy allows calibration with similar precision to a monoenergetic muon beam. Furthermore, the energy loss of muons in the inner detector can be studied. The results give good grounds for the permanent installation of the described calibration method. The measurement of the muon loss can be repeated on a regular basis. Thereby, the factors for the conversion of ADC values into energy (GeV) can be determined repeatedly, especially in a short run before real data taking. Deviations from the mean gas gain can be recognized for modules in the center of the HC Barrel. The homogeneity of the Hadron Calorimeter can be improved by introducing relative correction factors. (author) 66 figs., 22 tabs., 45 refs

[en] The results are reported of a potentiometric study of the reaction between UO₂²⁺ and the diazapolyoxamacrocycle ligands [2,2,2] and [2,1] in aqueous 0.1 M Et₄NClO₄ solution. It is concluded that the UO₂²⁺ group is not complexed by these ligands. (U.K.)

[en] The results of a simulation of the response of the L3 detector to hadrons is presented. The simulation is made on the basis of data obtained in the beam with the setup consisting of a uranium gas-sampling calorimeter with a bismuth germanium oxide calorimeter in front of it. (orig.)

[en] A prototype of a gas sampling uranium module of the L3 hadron calorimeter was built and subsequently tested with pion beams of energies between 4 and 20 GeV. The construction of the proportional chambers, the assembling of the module, the readout electronics, and the beam test are briefly described. The energy resolution of the calorimeter module alone was measured to be 30.5±3% at 6 GeV, 21±2% at 10 GeV and 18±2% at 20 GeV. For the module together with a BGO crystal matrix in front, the resolution was 29±3% at 4 GeV, 21±2% at 10 GeV, and 17±2% at 20 GeV. (orig.)

[en] The design and the mass production of the proportional wire chambers for the barrel part of the uranium-gas sampling hadron calorimeter of the L3 detector at the CERN Large Electron-Positron storage ring (LEP) are described. The chambers meet the specific requirements arising from the limited space available to the calorimeter, the radioactivity of uranium, and the physics criteria of good energy and position resolution for incident hadrons. The mass production techniques employed ensured that all of the 371664 chamber cells have uniform response (with 5% accuracy) to ionizing particles. Over 8000 chambers of the same design, in 53 different sizes, were manufactured and tested at the ITEP (Moscow), at the University of Michigan (Ann Arbor) and at the IHEP (Beijing). (orig.)

[en] Results of experimental studies of the performance of the uranium calorimeter with gas sampling detectors are presented. There is further evidence showing the importance of the contribution of the neutron component of a hadronic shower to the detected signal. The response and the resolution of the uranium calorimeter are measured in the momentum range 0.3-0.6 GeV/c for the different incident particles and different gases that are used in the detectors. For a calorimeter structure with double-gas-detector layers, the correlation between signals from two calorimeters formed by chambers filled with different gas mixtures is measured. The topics that are relevant to the performance of the L3 uranium-gas sampling calorimeter - such as its operation in the magnetic field, the energy dependence of muon response, the uranium noise, as well as the electronics optimization - are discussed. (orig.)

[en] The characteristics of the L3 hadron calorimeter as realized in the observation of hadronic jets and other events from e⁺e^- c collisions at LEP are presented and discussed. The pattern-recognition algorithm utilizing the fine granularity of the calorimeter is described, and the observed overall resolution of 10.2% for hadron jets from Z decay is reported. The use of the calorimeter in providing information on muon energy losses is also noted. (orig.)