Physics Commons^™

A Study Of Ion Implanted Silicon Using Rutherford Backscattering Spectroscopy With Ion Channeling, Thomas J. Pollock

Masters Theses

Rutherford Backscattering Spectroscopy with channeling is the only nondestructive method for analyzing crystals which have been ion implanted. An RBS with channeling procedure has been established at the Accelerator Lab of Western Michigan University. It utilizes a tandem Van de Graaff accelerator for an incident helium beam, a goniometer for crystal alignment, and a computer for experimental control and data aquisition. State of the art measurements can be made with accuracies comparable to other labs. Specifically, ion implanted silicon was studied wherein crystal damage due to implanting was found to vary directly with implanting energy and fluence and was also …

Effects Of A Magnetic Field On The Thermodynamics Of Dilute Classical Spin Chains, Guoqing Hu

Masters Theses

The thermodynamics of a diluted chain of ferromagnetic classical spin in the presence of an external magnetic field is determined in the limit of the continuum model. The magnetization, susceptibility, specific heat are determined for both the isotropic Heisenberg and the classical XY models as functions of temperature, magnetic field and magnetic concentration. Scaling law for the behavior of the thermodynamic quantities in field, temperature, and magnetic concentration are obtained.

The calculations will be based on the continuum model of classical spin which was solved for the infinite chain system by McGurn and Scalapino.

Thermodynamics Of The Diluted Spin Heisenberg Chain With Single Ion Anisotropy, Salmah Ahmed

Masters Theses

The thermodynamics of the one-dimensional diluted Heisenberg magnet of classical spins in the presence of single ion anisotropy is calculated. The magnetization, susceptibility, energy and specific heat are determined as functions of the magnetic concentration and single ion anisotropy for both ferromagnetic and antiferromagnetic couplings. Spin-spin correlation functions and the elastic scattering are also calculated for various values of anisotropy and spin concentration for the ferromagnetic system.

Theoretical Thermodynamic Properties Of Low Temperature Fluids, Zul Azhar Zahid Jamal

Masters Theses

The thermodynamic functions for low temperature fluids are computed using parametric integral equations and perturbation theory. Parametric integral equation N is applied to a low temperature Lennard-Jones gas. It is found that there is no significant improvement over the better known parametric integral equation C. The two parameter integral equation T is applied to a low temperature square-well potential and is found to be unsatisfactory at reduced temperatures of T*= 1.4 and 1.6, but quite accurate at T* = 2.2. The equation T results for T* = 2.2 are used as the reference system in perturbation theory computations. Tables of …

Hypernuclear Photoproduction Via (Γ,K*), Kimberly Ann Hodgkinson

Masters Theses

The nuclear (γ,K^*) reaction is studied using plane wave impulse approximation (PWIA) and a distorted wave impulse approximation (DWIA), which includes full Coulomb and optical distortions. The model and calculations for each model are presented. For ¹²C(γ K^*)¹²B, the two approximation methods are compared at 2 energies: 1.47 Gev/c and 1.84GeV/c. ²⁰⁸Pb(γ, K^*)²⁰⁸ i s a lso examined. Distortion effects are found to greatly alter the magnitude of the cross sections, but the shape of the angular distributions remains. the same. Conclusions suggest further study.

Testing Of Beam Line For Charge Exchange Measurements, Mohd. Noor Ali

Masters Theses

The atomic physics beam line in the Western Michigan University accelerator laboratory was tested for the first time for making atomic charge-exchange experiments. Cross sections obtained for single electron capture and loss for 25 MeV oxygen ions incident on a helium gas target are in reasonable agreement with previous measurements. These results indicate that the system is operating properly. An attempt to observe a nuclear resonance effect on electron capture and/or loss was not successful. However, it was determined that additional collimation is necessary for such measurements.

A Study Of The Direct Capture Process Of Protons By 27Al, Rozana Hussain

Masters Theses

An experimental investigation of the 27Al(p,γ)²⁸Si reaction was made for protons in the energy range 550- to 1785-keV and at angles of 0, 20, 55, 90 and 118 degrees. Four angular distributions at E_p = 845-, 1055-, 1135-, and 1618-keV were selected for detailed study. These angular distributions were fit with theoretical calculations employing a directcapture model. These fits permitted the extraction of spectroscopic factors for the population of the first excited-state in ²⁸Si by proton transfer.