Two-Dimensional Interdigitated Pixel Detector for Energetic Particle Spectrometers

Abstract

This paper describes a type of cosmic ray detector suitable for the construction of a small, low power space-based instrument to detect the energy and isotope of energetic nuclei, such as those produced by solar flares. The detector is similar to previous types of silicon PIN detectors where the fully depleted body of the wafer comprises the intrinsic region of the PIN structure. The novel aspect of this detector is that the one surface is divided into a 2D array of pixels, and that the collected holes are divided between a row and a column collector in each pixel, yielding both dimensions of position information from this side of the detector. In a conventional PIN detector, both sides are divided into stripes, and each side provides 1D information. A single large area collector on the opposite side of this new detector is used to determine the energy of the incident nucleus. This scheme requires only a single precision pulse-height amplifier connected to the broad area contract, rather than one for each strip, as in the conventional scheme, resulting in a significant reduction in the mass, power and complexity of the readout electronics. The design, fabrication, and operation of such a detector is discussed. Initial particle tests show a prototype to be functional. The projected power saved by using such as detector is presented.