Carbon Nanotubes-Based Radiation Detectors

Since lots of events in nature are followed by the emission of electromagnetic (e.m.) radiation in certain wavelengths regions, the necessity to observe, measure and analyze such events have driven the development of suitable radiation detectors. Electromagnetic radiation in the visible spectral region and its spectroscopical neighbourhood, Ultraviolet as well as Infrared, are of major interest since produced into a wide range of observable phenomena, from Sun emission to molecules fluorescence. In this field of investigation, for decades, the main detectors have been photomultipliers and silicon based photo-detectors. The firsts are based on the emission of electrons from the photocathode whereas the latter work by exploiting the generation of an electron-hole pair inside silicon junctions. Today the trend in photo-detectors research is twofold. On one hand the increase of sensitivity is constant in the development process. On the other hand, the extension of the photo-detector sensitivity to other spectral regions different from visible has gained increasing interest. The latter is mainly driven by new finding in the space observations of UV (300-400 nm) fluorescence tracks and the Cherenkov reflected bump of the extensive air shower induced by ultrahigh-energy particles traversing the atmosphere (Ebisuzaki et al., 2009). For space physics and for astroparticle physics envisaged for the next decade it will be indispensable to develop UV sensitive detectors, high pixelled and with high quantum efficiency, as described in the Cosmic Vision 2015-2025 plan for the ESA science program that cites: "The proposed mission will be based on large openings and large field-of-view optics with high throughput, as well as on large area, highly pixelled, fast and high detection efficiency near-UV camera". It is necessary therefore to start the job of developing matrices of detectors, suitable for single photon counting, finely pixelled on great surfaces, with great quantum efficiency and obviously low cost. Detectors that at the moment do not exist. In accelerators and space physics it is acquiring great importance the identification of particles through Cerenkov detectors like the RICH used in the ALICE experiment at CERN and AMS2 in the space station. Also in this case the Cerenkov light to detect is ultraviolet. In order to reconstruct the intersection ring of the emitted light cone with the sensitive surface of the detector it is necessary a finely pixelled UV detector with high quantum efficiency. Actually the most promising detectors are the SiPM for their fine structure and the ability to achieve amplification factors up to 106. However they introduce severe limitations: the