2006/04/26 by R. Bellazzini, G. Spandre, M. Minuti +16 · 2 citations
Engineering · Physics and Astronomy · #CCD and CMOS Imaging Sensors #Particle Detector Development and Performance #Photocathodes and Microchannel Plates #astro-ph #physics.ins-det
paper · pdf · doi:10.1016/j.nima.2006.07.036
published as Nucl.Instrum.Meth.A566:552-562,2006 · 14 pages, 18 figures, to be submitted to Nuclear Instruments and methode A
arxiv created 2006/04/26 · openalex publication_date 2006/08/11 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We report on a large active area (15x15mm2), high channel density (470 pixels/mm2), self-triggering CMOS analog chip that we have developed as pixelized charge collecting electrode of a Micropattern Gas Detector. This device, which represents a big step forward both in terms of size and performance, is the last version of three generations of custom ASICs of increasing complexity. The CMOS pixel array has the top metal layer patterned in a matrix of 105600 hexagonal pixels at 50 micron pitch. Each pixel is directly connected to the underneath full electronics chain which has been realized in the remaining five metal and two poly-silicon layers of a 0.18 micron VLSI technology. The chip has customizable self-triggering capability and includes a signal pre-processing function for the automatic localization of the event coordinates. In this way it is possible to reduce significantly the readout time and the data volume by limiting the signal output only to those pixels belonging to the region of interest. The very small pixel area and the use of a deep sub-micron CMOS technology has brought the noise down to 50 electrons ENC. Results from in depth tests of this device when coupled to a fine pitch (50 micron on a triangular pattern) Gas Electron Multiplier are presented. The matching of readout and gas amplification pitch allows to get optimal results. The application of this detector for Astronomical X-Ray Polarimetry is discussed. The experimental detector response to polarized and unpolarized X-ray radiation when working with two gas mixtures and two different photon energies is shown. Results from a full MonteCarlo simulation for several galactic and extragalactic atronomical sources are also reported.