Particle physics experiments: From photography to integrated circuits

AbstraktAbstract

Over the last decades the experiments in elementary particle physics at the new colliding beam accelerators with TeV energy, in particular the LHC at CERN, have seen profound changes. These present orders of magnitude increases in physical size, interaction rates, radiation intensity and data volume. Not only new instruments such as segmented and pixelated silicon detectors, but also calorimeters and surrounding muon detectors feature a much larger number of sensing elements. This provides improved precision in particle tracking and momentum measurement, avoiding a need for even larger overall detector dimensions. Associated silicon integrated circuits, specifically designed for these applications, improve the speed and reduce the electrical power for signal processing and information extraction. Now the detectors can cope with near-GHz interaction rates, more than 1000-fold the rate at the LEP collider ∼1995, and produce distinctive reconstructions of interactions with μm-level precision, even with hundreds of simultaneous particles. All this in the inherently severe radiation environment up to tens of Mrad. The unconventional exploitation of silicon chip technology for radiation sensing and large-scale parallel signal processing has been the most important enabling factor. Some of the successive steps in the introduction of the silicon devices are described here in a narrative way, and with an unavoidable personal bias of the author. General characteristics of this electronics are outlined, including a brief description of IC manufacturing technologies. The focus is on the inner vertexing and tracker systems, which profited most of the miniaturization. References are made to further articles in the special issue, which treat in more detail the instruments and associated circuits for readout, precision timing and voluminous data transmission, by wire or optical fiber. In the margin, historical circumstances are indicated, which made the ‘silicon revolution’ possible and affordable for high energy physics.

Over the last decades the experiments in elementary particle physics at the new colliding beam accelerators with TeV energy, in particular the LHC at CERN, have seen profound changes. These present orders of magnitude increases in physical size, interaction rates, radiation intensity and data volume. Not only new instruments such as segmented and pixelated silicon detectors, but also calorimeters and surrounding muon detectors feature a much larger number of sensing elements. This provides improved precision in particle tracking and momentum measurement, avoiding a need for even larger overall detector dimensions. Associated silicon integrated circuits, specifically designed for these applications, improve the speed and reduce the electrical power for signal processing and information extraction. Now the detectors can cope with near-GHz interaction rates, more than 1000-fold the rate at the LEP collider ∼1995, and produce distinctive reconstructions of interactions with μm-level precision, even with hundreds of simultaneous particles. All this in the inherently severe radiation environment up to tens of Mrad. The unconventional exploitation of silicon chip technology for radiation sensing and large-scale parallel signal processing has been the most important enabling factor. Some of the successive steps in the introduction of the silicon devices are described here in a narrative way, and with an unavoidable personal bias of the author. General characteristics of this electronics are outlined, including a brief description of IC manufacturing technologies. The focus is on the inner vertexing and tracker systems, which profited most of the miniaturization. References are made to further articles in the special issue, which treat in more detail the instruments and associated circuits for readout, precision timing and voluminous data transmission, by wire or optical fiber. In the margin, historical circumstances are indicated, which made the ‘silicon revolution’ possible and affordable for high energy physics.