The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project. ?? 2013 Elsevier B.V. All rights reserved

In this work it is shown the benefit of using pulse shortening systems for conforming photodetection pulses provided by Silicon Photomultipliers (SiPMs). One of the main drawbacks when using SiPMs is the slow falling edge in the detection signal which can reach even hundreds of nanoseconds. Pulses obtained when using the shortening systems proposed here are single narrow peaks, with full width at half maximum (FWHM) around 10 ns, preserving the photonic modulation and with good pseudo-gaussian shape, single polarity and low ringing. Different tests are presented to illustrate the advantage of these systems in the detection of single photons emitted in short, incoherent pulses.

Abstract. In this work, three strategies for shortening the output pulse of a silicon photomultiplier (SiPM) are reported. The first strategy is passive filtering, where band-pass filtering removes the lowest frequency components in the signal, getting a noticeable reduction in pulse width (a compression ratio of 10∶1 was obtained). In the second place, a reflectometric scheme is proposed where the amplified signal coming from the SiPM is injected into a signal splitter with one of its stubs connected to a short-circuited stub. In the last strategy, the reflectometric part is replaced by an analog subtractor circuit. In this approach, a signal splitter with stubs of different lengths is used. All solutions provide good compression ratios, up to 10∶1. Best pulses obtained are single narrow peaks, with width below 10 ns, preserving the photonic modulation and with good pseudoGaussian shape, single polarity and low ringing. The potential of pulse shortening for improving the capability of the detector to resolve single photons is demonstrated by mean of single photon counting patterns. The detection error probability is reduced in one order of magnitude when shortening is used for conditioning the output photosignal. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).

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