Date of Completion

Spring 5-2010

Thesis Advisor(s)

Richard Jones

Honors Major



Atomic, Molecular and Optical Physics | Physics


In quantum chromodynamics (QCD), quarks and antiquarks are held together inside hadrons by the nuclear strong force, which is mediated by exchange particles known as gluons. The simplest type of hadron, the meson, consists of a single quark and a single antiquark bound by a gluonic field. The flux-tube model of QCD says that this gluonic field forms a tube of color-electric field lines between the quark and the antiquark which can under the right conditions be made to vibrate. Such mesons with excited glue are called hybrid mesons.

GlueX is a high-energy nuclear physics experiment which will study hybrid mesons and map their spectrum. To produce hybrid mesons, GlueX will make use of Thomas Jefferson National Accelerator Facility’s 12 GeV electron accelerator. Electrons from the accelerator will pass through a diamond crystal, where they will radiate high-energy gamma rays through a process known as bremsstrahlung radiation. These gamma rays, in turn, interact with protons in a liquid hydrogen target, and their energy is converted into mass in the form of new particles, mostly hadrons. This process is known as photoproduction. Among the hadrons produced by this process, GlueX experimenters expect to find hybrid mesons. In order to identify the hybrid mesons among the other particles produced in the target, it is essential to know the energy and the precise time at which each gamma ray interacts with a proton in the target. A device called the photon tagger is responsible for detecting electrons after they leave the diamond radiator and measuring how much energy they radiated in the bremsstrahlung process. The design of electronics for the photon tagger is the focus of this thesis.