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A solid state radiation measurement system was designed and developed to handle extremely high flux (approaching 0.9Mcps) and a large dynamic range. To achieve this the system utilizes a CdZnTe crystal that has undergone prior high flux testing with high bias to ensure it will not exhibit significant depolarization that will limit its ability to measure high flux. In addition, a preamplifier that produces a very narrow pulse (~125ns FWHM), was designed and a high speed ADC was used to digitize the pulse. A Field Programmable Gate Array (FPGA) was implemented that allowed for scalable (2 or more channels counting asynchronously), high speed (130 MHz) pulse analysis in real time. The FPGA uses a pulse recognition algorithm to recognize pulses, even those beginning to pile up onto one another. This system was tested with a high energy (511keV) source that had an activity exceeding 10Ci.

This work was part of a pilot clinical study that involved the placement of an intracortical implant in the primary motor cortex of human subjects. The study, the first of its kind, involved the implantation of a 96 electrode array in the human brain for up to a full year. The work described here involved two of the subjects in the study, one of which was a stroke victim, and the other had ALS. Both subjects were tetraplegic and also unable to speak. The intent of this work was to determine if intended/imagined movements would evoke neural activity that could be successfully decoded and allow the subjects to control various devices in their environment and communicate through a personal computer. Neural decoding algorithms were developed to interpret the intracortical activity in the primary motor cortex of both subjects. Adaptive support vector machine methods were developed and employed during this study. A large set of intended/imagined movements was successfully decoded and discriminated between with the first subject. Also, both imagined shoulder and wrist movements were decoded in the second subject. Finally, the algorithms developed in this work allowed, for the first time, control of a motorized wheelchair through intended/imagined movements in a human with an intracortical electrode array implant.