3D cosmic-ray muon tomography using portable muography detector

A feasibility demonstration of three-dimensional (3D) muon tomography was performed for infrastructure equivalent targets using the proposed portable muography detector. For the target, we used two sets of lead blocks placed at different heights. The detector consists of two muon position-sensitive detectors, made of plastic scintillating fibers (PSFs) and multi-pixel photon counters (MPPCs) with an angular resolution of 8 msr. In this work, the maximum likelihood-expectation maximization (ML-EM) method was used for the 3D imaging reconstruction of the muography. For both simulation and experiment, the reconstructed positions of the blocks produce consistent results with prior knowledge of the blocks' arrangement. This result demonstrates the potential of the 3D tomographic imaging of infrastructure by using seven detection positions for portable muography detectors to image infrastructure scale targets.

Development of Extrospective Systems for Mobile Robotic Vehicles.

<p>Extrospection is the process of receiving knowledge of the outside world through the senses. On robotic platforms this is primarily focussed on determining distances to objects of interest and is achieved through the use of ranging sensors. Any hardware implemented on mobile robotic platforms, including sensors, must ideally be small in size and weight, have good power efficiency, be self-contained and interface easily with the existing platform hardware. The development of stable, expandable and interchangeable mobile robot based sensing systems is crucial to the establishment of platforms on which complex robotic research can be conducted and evaluated in real world situations. This thesis details the design and development of two extrospective systems for incorporation in the Victoria University of Wellington's fleet of mobile robotic platforms. The first system is a generic intelligent sensor network. Fundamental to this system has been the development of network architecture and protocols that provide a stable scheme for connecting a large number of sensors to a mobile robotic platform with little or no dependence on the existing hardware configuration of the platform. A prototype sensor network comprising fourteen infrared position sensitive detectors providing a short to medium distance ranging system (0.2 - 3 m) with a 360' field of view has been successfully developed and tested. The second system is a redesign of an existing prototype full-field image ranger system. The redesign has yielded a smaller, mobile version of the prototype system capable of ranging medium to long distances (0 - 15 m) with a 22.2' - 16.5' field-of-view. This ranger system can now be incorporated onto mobile robotic platforms for further research into the capabilities of full-field image ranging as a form of extrospection on a mobile platform.</p>

Development of Extrospective Systems for Mobile Robotic Vehicles.

<p>Extrospection is the process of receiving knowledge of the outside world through the senses. On robotic platforms this is primarily focussed on determining distances to objects of interest and is achieved through the use of ranging sensors. Any hardware implemented on mobile robotic platforms, including sensors, must ideally be small in size and weight, have good power efficiency, be self-contained and interface easily with the existing platform hardware. The development of stable, expandable and interchangeable mobile robot based sensing systems is crucial to the establishment of platforms on which complex robotic research can be conducted and evaluated in real world situations. This thesis details the design and development of two extrospective systems for incorporation in the Victoria University of Wellington's fleet of mobile robotic platforms. The first system is a generic intelligent sensor network. Fundamental to this system has been the development of network architecture and protocols that provide a stable scheme for connecting a large number of sensors to a mobile robotic platform with little or no dependence on the existing hardware configuration of the platform. A prototype sensor network comprising fourteen infrared position sensitive detectors providing a short to medium distance ranging system (0.2 - 3 m) with a 360' field of view has been successfully developed and tested. The second system is a redesign of an existing prototype full-field image ranger system. The redesign has yielded a smaller, mobile version of the prototype system capable of ranging medium to long distances (0 - 15 m) with a 22.2' - 16.5' field-of-view. This ranger system can now be incorporated onto mobile robotic platforms for further research into the capabilities of full-field image ranging as a form of extrospection on a mobile platform.</p>

APPLICATION OF POSITION-SENSITIVE DETECTORS FOR ANALYZING THE ENERGY SPECTRA OF PHOTON RADIATION

Monitoring the spectral composition of photon radiation from generating sources and emitting objects is the most informative way to analyze the radiation fields created by them. However, it is impossible to study the radiation characteristics of radiation fields of ultra short duration and high intensity using direct measurement methods. This work considers a method for reconstructing the spectral distributions of photon radiation from the profile of the secondary radiation fields recorded by a position-sensitive detector. To implement a new method of measurement in the primary beam of radiation is an extended scattering body of homogeneous material. Outside the field of the primary beam, a position-sensitive detector is placed along the generatrix of the scattering body, which records the photons of the secondary radiation and the coordinates of their emission. The spectral composition of the primary radiation beam is restored from the shape of the spatial distribution obtained. To find a quasi-solution describing the energy spectrum of the primary radiation beam, it is proposed to use the maximum likelihood expectation maximization method. The possibility of switching to measurements in secondary radiation fields having a lower intensity is confirmed by the experimental results. To form secondary radiation fields, we used a composite phantom containing three scattering bodies in the form of rectangular parallelepipeds made of graphite, aluminum, and titanium. The secondary radiation fields were recorded by a radiographic sensor. Using an X-ray source operating in a pulsed mode, images were obtained and profiles of the secondary radiation fields were formed. It is experimentally shown that the secondary radiation fields have a gradient structure and can be used to analyze the energy spectra of the radiation beams generating them. The method for reconstructing spectral distributions proposed in this work allows one to measure the energy spectra of photons using position-sensitive detectors and can be used in solving problems of diagnostics of pulsed high-intensity radiation beams.