Speckle interferometry and a study for Γw for the ATLAS experiment

• Main Author: Clark, Daniel Carlos Buira
• Format: Dissertation
• Language: English
• Published: University of Oxford 2006

The ATLAS experiment is being assembeled as a general purpose particle detector to exploit the physics discovery potential of the Large Hadron Collider. The SemiConductor Tracker (SeT), one of the central subsystems of ATLAS, requires alignment of O(lDJ.Lm) for good performance. The alignment program consists of a set of proceedures to establish the location of detector elements. This includes optimised design and construction prior to operation. This thesis describes Electronic Speclde Pattern Interferometry (ESPI), a technique used to measure deformation at the micron level which has been applied to SCT components during design and prototype development. ESPI creates contour maps of objects under study, helping a qualitative understanding of object behaviour as well as providing measurements. ESPI measurements of the thermal deformation of SCT detector modules are presented. A modified ESPI interferometer was developed to create contours of vibration amplitude. Tests were performed on well-understood objects to ensure consistency between the interpretation of Vibration ESPI results and known object behaviour. The technique was then used to measure the behaviour under acoustic driving of prototype SCT support structures made of Carbon-Fibre Reinforced Plastic (CFRP) materials. Several low modes of oscillation were found, as well as the oscillator quality factor, for each of the CFRP structures studied. These results provide design input for SCT construction by specifying resonant frequencies to avoid) and corroborate the validity of Finte Element Analysis studies on these inhomogeneous materials used in the ATLAS SCT. High event statistics will permit ATLAS perform precision Electroweak measurements. This thesis presents a study of the statistical resolution with which the decay width of the W boson, rw will be measured.