Thesis (M.S.) in Mechanical Engineering--University of Maine, 2001. / Includes vita. Includes bibliographical references (leaves 54-55).

Accurate quantification of radionuclides detected during a scanning survey relies on an appropriately determined scan efficiency calibration factor (SECF). Traditionally, instrument efficiency was determined from a fixed instrument to source geometry. However, as is often the case, the instrument is used in a scanning mode where the source to instrument geometry is dynamic during the observation interval. Three separate procedures were developed to determine the SECF for a 10 cm x 10 cm source passing under the centerline of a 12.7 cm x 7.62 cm NaI(T1) detector. The procedures were first tested for determining the SECF from a series of static point source measurements generated by the Monte Carlo N-Particle (MCNP) code. These static efficiency values were then used to predict the SECF for scan speeds ranging from 10 cm s����� to 80 cm s����� with a one second observation interval. The investigator then used MCNP to directly determine the SECF by simulating a scan of a 10 cm x 10 cm area source for scan speeds ranging from 10 cm s����� to 80 cm s�����. Comparison of the MCNP static simulation with the scan simulation showed the accuracy of the SECF prediction procedures to be within ��5%. Experimental results further show the three procedures developed to predict the actual SECF for a 10 cm x 10 cm source to be accurate to within ��10%. Besides the obvious application to determine an SECF for a given scan speed, this method can be used to determine the maximum detector or source velocity for a desired SECF. These procedures are effective and can likely be extended to determine an instrument specific SECF for a range of source sizes, scan speeds, and instrument observation intervals. / Graduation date: 2002

Thesis (M.S.)--Rochester Institute of Technology, 1986. / Typescript. Includes bibliographical references (leaf 40).

No description available.

A scanning force microscope is an instrument which can image the forces present on a sample with high resolution. These forces include magnetic, electric, and atomic forces. The scanning force microscope uses either a tunneling, capacitive or optical method of sensing the motion of a lever-tip mechanical system that reacts to the forces present on a sample. There are four optical methods used in scanning force microscopy: heterodyne, homodyne, deflection and laser feedback. In this thesis, two implementations of the laser feedback method of detecting lever motion are described: a fiber coupled laser diode feedback and a tightly coupled laser diode feedback. The theory of interactions between a tip and the magnetic or electric fields at the surface of a sample are presented, along with the theory of the laser diode feedback. The limiting noises inherent in the system are discussed and representative values are given. Results of the sensitivity of the two systems are presented, and images of electric forces acting on the tip from interdigitated electrodes are demonstrated.

No description available.

No description available.

Thesis (M.S.)--Ohio University, August, 1986. / Title from PDF t.p.

Thesis (M.S.)--Ohio University, March, 1995. / Title from PDF t.p.

Thesis (M.S.)--West Virginia University, 2003 / Title from document title page. Document formatted into pages; contains vi, 87 p. : ill. (some col.) Includes abstract. Includes bibliographical references (p. 86-87).