[en] A prototype NaI(Tl) detector (the Cluster of 54) of spherical geometry subtending a solid angle of 7.5 percent of 4π at its center, has recently been assembled and tested. This detector consisted of 54 close-packed but optically isolated NaI(Tl) modules and the associated electronic circuitry. The Cluster of 54 is the predecessor of an almost complete spherical detector, the Crystal Ball, which will cover 94 percent of 4π. The latter detector is now under construction and is especially designed for the study of γ-rays produced in electron-positron collisions at colliding beam facilities. The mechanical, optical, and electronic assembly of the prototype system is outlined. Cluster of 54 test data will be presented

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[en] Some recent results in e+e- physics from Cornell on bb spectroscopy, from SPEAR on cc spectroscopy, and from the Crystal Ball related to charmed mesons are reviewed. The new storage ring at Cornell, with CLEO and CUSB detectors, gives the mass of the B meson, the sum of two semi-leptonic branching ratios, and an upper limit on the lifetime of the B. The hypothesis that T(4S) → BB predominantly is accepted. For experiments at SPEAR with Mark II and the Crystal Ball only the /eta/(nu) /SUB c/ candidate, the radiative transitions involving three /chi/ states and the exclusive radiative decays of the psi are studied

[en] Although the people who studied photon detectors for e⁺e^- storage rings at the 1974 PEP Summer Study did not know about the soon-to-bediscovered charmed quarks, subsequent events have shown that the practical realization of their ideas has borne rich rewards in understanding this sector of nature. The Crystal Ball detector grew out of that work and, as this brief review shows, it has proved to be an especially versatile instrument in spite of features (or lack of them) that at first sight would make it seem to be very specialized and restricted in application. Of course, the dominant strength of this detector has been, and always will be, the measurement of monochromatic photons, and it was this capability that allowed the Ball to resolve the old problems with the charmonium interpretation of psionic matter. However, the measurements of R /SUB h/ , for example, demonstrate the instrument's ability to determine global properties of e⁺e^- annihilations. At the other extreme, kinematically constrained fitting to very specific final states that include just two charged particles but are rich in photons has been successfully exploited

[en] A brief review is given of the design and applications of the ''crystal ball'' detector, formerly at SPEAR and now at DESY. The energy levels and decay properties of charmonium are considered in detail

No abstract available

[en] A prototype NaI(Tl) detector (the Cluster of 54) of spherical geometry subtending a solid angle of 7.5% of 4π at its center has recently been assembled and tested. This detector consisted of 54 close-packed but optically isolated NaI(Tl) modules and the associated electronic circuitry. The Cluster of 54 is the predecessor of an almost complete spherical detector, the Crystal Ball, which will cover 94% of 4π. The latter detector is now under construction and is especially designed for the study of α-rays produced in electron-positron collisions at colliding beam facilities. An outline is presented of the mechanical, optical, and electronic assembly of the prototype system. Cluster of 54 test data are presented. 2 refs

[en] Evidence for an eta/sub c/ candicate with a mass of 2980 +- 15 MeV from the psi' inclusive γ spectrum is presented. The corresponding region in the J/psi inclusive γ spectrum is then studied and shown to be consistent with a broad Breit-Wigner enhancement superimposed upon a smooth background. Results from a detailed study of the two exclusive decay modes psi'→γγ psi→γγ e⁺e^- and psi'→γγ psi→γγμ⁺μ^- are also given. These consist of measurements of the cascade branching ratios BR(psi'→γchi→γγpsi) for chi(3.55) and chi(3.51) and upper limits on this branching ratio for chi(3.41), chi(3.45), and chi(3.59). Finally, we give branching ratios for the two decays psi'→etapsi and psi'→π ⁰psi

[en] Muon energy measurement represents an important issue for any experiment addressing neutrino-induced up-going muon studies. Since the neutrino oscillation probability depends on the neutrino energy, a measurement of the muon energy adds an important piece of information concerning the neutrino system. We show in this paper how the MACRO limited streamer tube system can be operated in drift mode by using the TDCs included in the QTPs, an electronics designed for magnetic monopole search. An improvement of the space resolution is obtained, through an analysis of the multiple scattering of muon tracks as they pass through our detector. This information can be used further to obtain an estimate of the energy of muons crossing the detector. Here we present the results of two dedicated tests, performed at CERN PS-T9 and SPS-X7 beam lines, to provide a full check of the electronics and to exploit the feasibility of such a multiple scattering analysis. We show that by using a neural network approach, we are able to reconstruct the muon energy for E_μ<40 GeV. The test beam data provide an absolute energy calibration, which allows us to apply this method to MACRO data