[MUSIC] In this video, I will give you a little insight into how one uses the particle detectors which we have introduced in Module 3 to detect charged particles and light. At the end of this video you will know how one integrates semiconductor sensors into so-called particle trackers, which reconstruct the trajectory of particles, and how one uses light detection techniques to detect particles using scintillators. We have already introduced the principles of particle detection by semiconductor detectors in video 3.8, and by scintillators in video 3.9. So, to my right, you see two applications of semiconductor detectors, on top for the ATLAS experiment of the LHC at CERN, and below by the space experiment AMS installed on the International Space Station. Let us start by the top set-up. You see here a part of the ATLAS forward detector and the particles enter this part of the detector in roughly this direction. They are localised by these silicon microstrip detectors, which you see on my left. There are in fact two superimposed detectors, glued to each other. They make a small angle, which permits, even by a detector with single sided read out, to localise the particles in three dimensions. You see on the bottom of each detector a small electronics card, directly connected to the detector, which shapes the signal and, when a trigger arrives, transmits it, in this case an optical signal, through this slim optical fibre coming out. You also see this piping behind, which is part of the detector infrastructure, and which transports a cooling liquid, absorbing the heat and stabilising the temperature of detector and electronics. The second line of particle detectors, which we very actively follow here at the Department of Nuclear and Particle Physics of the University of Geneva, are scintillation detectors, which we have already introduced in video 3.9. So, here you see the classical way of constructing a scintillation detector. You take a scintillating material, you connect it via a light guide to a photomultiplier. In the past, in the 1970-80’s, these were vacuum tubes, very bulky and heavy. And here you see the direction which is being followed today. On can produce scintillating fibres, very fine ones, which can be connected to a very small light detector like this one, which allows at the same time to localise particles ant to measure their specific energy loss dE/dx, as we have explained in video 3.9. Once integrated, the set-up looks roughly like this, you see a fine layer of scintillators directly coupled to a semiconductor light detector, which localises light emission and measures its intensity, produced by the passage of the particle. With this one can also construct particle tracking detectors, which are light, deformable and can be adjusted to practically any detector shape since the whole stays flexible and can be made to made to follow almost any desired form. With this, you have seen two of our specialties in the development of novel particle detectors. But we do not stop here. The direction we follow for semiconductor sensors goes towards pixel detectors, which allow, in the same sensor, to directly localise particles in two directions. They also present an improvement in resolution, which is rather impressive. You see here a sensor, which localises particles to about ten micrometers. I remind you that the diameter of a human hair is about 100 micrometers, i.e. the sensor localisation is 10 times more precise. [MUSIC]