The CEBAF large acceptance spectrometer (CLAS) is used to study photo- and electro-induced nuclear and hadronic reactions by providing efficient detection of neutral and charged particles over a good fraction of the full solid angle. A collaboration of about 30 institutions has designed, assembled, and commissioned CLAS in Hall B at the Thomas Jefferson National Accelerator Facility. The CLAS detector is based on a novel six-coil toroidal magnet which provides a largely azimuthal field distribution. Trajectory reconstruction using drift chambers results in a momentum resolution of 0.5% at forward angles. Cherenkov counters, time-of-flight scintillators, and electromagnetic calorimeters provide good particle identification. Fast triggering and high data-acquisition rates allow operation at a luminosity of View the MathML source. These capabilities are being used in a broad experimental program to study the structure and interactions of mesons, nucleons, and nuclei using polarized and unpolarized electron and photon beams and targets. This paper is a comprehensive and general description of the design, construction and performance of CLAS

Experimental Hall B at Je!erson Laboratory houses the CEBAF Large Acceptance Spectrometer, the magnetic "eld of which is produced by a superconducting toroid. The six coils of this toroid divide the detector azimuthally into six sectors, each of which contains three large multi-layer drift chambers for tracking charged particles produced from a "xed target on the toroidal axis. Within the 18 drift chambers are a total of 35,148 individually instrumented hexagonal drift cells. The novel geometry of these chambers provides for good tracking resolution and e$ciency, along with large acceptance. The design and construction challenges posed by these large-scale detectors are described, and detailed results are presented from in-beam measurements.

Patients treated with CoSeal® in this study had, as a group, a longer duration of air leak and hence we cannot recommend its routine use.

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The inability to predict the point of strike of natural lightning flashes to ground makes it very difficult to carry out repeated measurements under reasonably reproducible conditions. This difficulty has been overcome to some extent by measurements on discharges to high buildings, radio towers, power lines, and other fixed structures. During the last several years we have experimented with long wires carried aloft by rockets to induce strokes from overhead thunder‐clouds. These strokes will be referred to as triggered lightning strokes. Early experiments with the schooner Azara [Newman, 1958, 1965] have been continued with our research vessel R. V. Thunderbolt in the vicinity of St. Petersburg, Florida. During August 1966, of 23 attempts 17 cloud‐vessel lightning flashes were successfully triggered.