Japan Science and Technology Corporation

Atsuhiko Ochi

Toru Tanimori

A particle beam image detector employing gas amplification attained by pixel-type electrodes has high sensitivity and improved reliability of electrodes. Electrons e produced through ionization of the gas move under the force of a drift field toward a pixel in the form of a columnar anode electrode. Avalanche amplification occurs in the vicinity of the columnar anode electrode due to a strong electric field between anode and cathode and the pointed shape of the electrode. The positive ions quickly drift toward strip-shaped cathode electrodes. Electric charges are generated on the columnar anode electrodes and also on the strip-shaped cathodes and these electric charges are observable to determine the anode or cathode strip at which this amplification phenomenon occurs and thus to obtain information as to position of the incident particle beam.

Corpuscular beam image detector using gas amplification by pixel type electrodes

An imaging microstrip gas chamber (MSGC) high-speed data acquisition system capable of processing at high speed a large number of output signals of an imaging microstrip gas chamber. The system includes discrimination circuits for binary conversion of signals from anode strips and back strips of a two-dimensional microstrip gas chamber; signal synchronizing circuits for converting binary asynchronous signals output from the discrimination circuits into clock-synchronized signals; data encoder circuits connected to the signal synchronizing circuits; an incident-particle hit judgment circuit connected to the data encoder circuits and operating such that when a plurality of adjacent signal lines receive signals at the same timing, a value corresponding to a signal line at the center of the adjacent signal lines is output, and when separated signal lines receive signals at the same timing, the signals are ignored; a storage device connected to the incident-particle hit judgment circuit and adapted to store, for each event, the vertical and horizontal coordinates of an incident particle, the timing of incidence of the particle, the degree of spreading of output signals, and the energy of the incident particle obtained from an overall pulse height; and a computer connected to the storage device.

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Tokyo, Japan

Atsuhiko Ochi