Fast Beam Intensity Measurements for the LHC

Particle accelerators are constructed and operated for a wide variety of applications. In particle physics - the branch of physics that studies the elementary constituents of matter and forces between them - high energy accelerators are used to look deep into the structure of matter. Medical particle accelerators are used for example in medicine to treat tumours [31], in imaging techniques such as Positron Emission Tomography (PET) [24], or for the radio-isotopes production. They also serve in many other industrial branches, e.g. geology, radiocarbon dating [39], molecular complex spectroscopy, lithography, food preservation etc. The eld of accelerator technology draws knowledge and expertise from a wide range of scientic disciplines and uses the latest technical knowledge. The incomplete list of covered disciplines includes mathematics, physics, electronics, computing, electromagnetic eld technology, microwave technology, cryogenics, vacuum technology, special materials, mechanical engineering or civil engineering. Eective control of an accelerator requires numerous types of diagnostic tools. The tools providing an information about the beam parameters are called eam diagnostics". They include many measurement techniques which could be grouped into two major branches: Intercepting measurements, which are destructive for the beam, or they result in absorption of a signicant amount of its energy. These include e.g. wire scanner s (monitors which detect longitudinal prole of the beam of particles) [6], Secondary Emission (SEM) grids (measurement of transversal beam prole) [9], Optical Transition Radiation (OTR), scintillator or Yttrium Aluminium Garnet (YAG) screens (measurement of beam size and position) [75], and few techniques of beam intensity measurements as Faraday cup measurement [29]. Non-intercepting measurements, which use electric or magnetic eld coupling of beam to the measuring instrument. These include e.g. a beam position measurement [12], emittance and acceptance measurements, beam loss measurement, luminosity [7] [8] and tune measurements [13], and capacitive or inductive beam intensity measurements (either AC or DC). Currently, a new and unique accelerator is being commissioned at the European Organisation for Nuclear Research (CERN), Switzerland - the Large Hadron Collider (LHC). The LHC rstly started the beam production at the end of 2008. A year later, in November 2009, it had already set the new record in the achieved beam energy - the protons were accelerated to 1.2 GeV. The LHC's unique parameters - circumference of 27 km, extreme collision energy (14 TeV), very ne spatial bunches distribution and separation (beam longitudinal RMS size from 280 ps to 680 ps repeated at 25 ns) - require substantial changes in the fast beam intensity measurement methods currently used at CERN. This doctoral thesis aims to design, optimise and imp lement the fast (AC) beam intensity measurement system to measure the intensity of the LHC circulating beams.