This paper describes the design and operation of a 40 spatial channel Thomson scattering system that uses multiple 20-Hz Nd:YAG lasers to measure the electron temperature and density profiles periodically throughout an entire plasma discharge. As many as eight lasers may be fired alternately for an average measurement frequency of 160 Hz, or they may be fired in rapid succession (<10 kHz), producing a burst of pulses for measuring transient events. The high spatial resolution (1.3 cm) and wide dynamic range (10 eV–20 keV) enable this system to resolve large electron density and temperature gradients formed at the plasma edge and in the scrape-off layer during H-mode operation. These features provide a formidable tool for studying L–H transitions, edge localized modes (ELMs), beta limits, transport, and disruptions in an efficient manner suitable for large tokamak operation where shot-to-shot scans are impractical. The scattered light is dispersed by interference filter polychromators and detected by silicon avalanche photodiodes. Laser control and data acquisition are performed in real time by a VME-based microcomputer. Data analysis is performed by a MicroVAX 3400. Additional features of this system include real-time analysis capability, full statistical treatment of error bars based on the measured background light, and laser beam quality and alignment monitoring during plasma operation. Results of component testing, calibration, plasma operation, and error analysis are presented.

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Cosmogenic radionuclides were measured on 48 fragments of 24 meteorites which fell between 1967 and 1978. Nondestructive gamma counting techniques were used to obtain data on 7Be, 46Sc, 48V, 51Cr, 54Mn, 56Co, 57Co, 58Co and 60Co on at least some of the samples. Sodium 22 and 26Al measurements are reported on all 48 samples. In addition, new rare gas data and exposure ages are reported for the meteorites Guibga, Gorlovka, Dhajala, Louisville, Acapulco, Jilin, Kabo, Alta‐Ameen, and Canon City. The cosmogenic radioisotope and rare gas data are interpreted in terms of a time dependent modulation of galactic cosmic rays spanning one full 11 year sun spot cycle. Special attention is given to the data on 22Na, 46Sc, 54Mn, and 48V with either 26Al or 22Ne/21Ne used to provide a shielding correction. The shielding normalized data using the 26Al method appear to correlate well with calculated production rates scaled against the Deep River neutron monitor. The data for the four isotopes are consistent with a production rate variation of a factor of 2.5–3 between solar maximum and solar minimum for sun spot cycle 20. These data demonstrate that the production rates of cosmic ray‐produced nuclides in meteorites vary considerably according to modulation by the 11‐year solar cycle and support the concept that variations of solar‐modulated, cosmic ray flux of similar magnitude have occurred over much longer time periods.