The Identification of Particle Species Through the Use of Specific Ionization Measurements.
This thesis presents the results of a research effort to produce a dE/dx based particle identification system for the CLEO experiment at the Cornell Electron Storage Ring. The merits and potentialities of such a device are discussed. A review is made of the current theoretical understanding of the energy loss of charged particles in matter. Particular emphasis is given to including the "density effect" in the energy loss calculations and to developing an analytic method for describing the energy loss distribution n thin samples. Data from studies using a prototype pressurized wire chamber with incident 1 and 4 GeV/c muons are presented. In particular, a measurement of the relativistic rise in ionization loss for 4 GeV/c muons relative to 1 GeV/c muons is pesented. The performance of the device is evaluated with respect to changes in the sample size and the number of samples. A brief description of the CLEO experiment is made. Some aspects of multiwire proportional chambers relevant to the design of a dE/dx based particle identification system are discussed. In particular, attention is paid to mathematically modeling the properties of wire chambers. Green's reciprocating theorem is used to explain the electrostatic cross-talk among wires in a proportional chamber. The design criteria for the CLEO dE/dx system are discussed, and a description of the final design is given. The operating experience obtained in the hadron test beam at the Alternating Gradient Synchrotron at Brookhaven National Laboratory, and in the electron test beam at the Wilson Synchrotron Laboratory is discussed. In addition, the performance of the device as part of the CLEO experiment is discussed. In particular, attention is focused on the data obtained from (mu)-pairs, Bhabha electrons, and hadronic events. The utility of the dE/dx system is demonstrated in comparisons with time-of-flight identified samples of pions and kaons. An attempt is made to extract the number of charged kaons per B-meson decay. The result is compared with that obtained from the independent time-of-flight analysis.
- Pub Date:
- Physics: Elementary Particles and High Energy