ELECTROOPTICAL MODULATORS IN PARTICLE DETECTORS

Results of an investigation to minimize the local electronics in parti cle detectors using electro-optical intensity modulators are reported. The electrical charge signals from a particle detector are first appl ied to a low noise electronic charge-sensitive preamplifier and the re sulting signal charges are converted into optical signals using an int egrated Ti:LNbO(3) Mach-Zehnder interferometric optical modulator. By driving the optical modulator with a low noise diode-pumped Nd:YAG las er at a wavelength of 1.3 mu m and detecting the output signals using a fast pulse shaping technique, the charge output of a particle detect or can be measured at high rates with high accuracy up to 3 decades of dynamic range. The performance characteristics of such a detector sig nal transfer scheme, using first a single channel optical modulator an d then a 16-channel integrated optical modulator array, is reported. U sing the charge output from a multiwire proportional chamber, this ele ctrical charge to optical signal transfer scheme is compared to the co nventional particle detection technique. Effects of radiation dose on the optical modulator are also presented. Finally, the implication of using such an optical technique is discussed. (C) 1995 American Instit ute of Physics.