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An <I>in vivo</I> neutron inelastic scattering activation analysis based on the associated particle timing method is being developed with imaging capability. A proposed imaging system, the Associated Particle Imaging System (APIS) has been described. The APIS is based on identifying the spatial origin, of a measured neutron induced prompt gamma ray, by a position sensitive detection of the associated particle (the helium nucleus). Using the D-D reaction at neutron energy of 2.8 MeV elemental analysis of bulk samples has been demonstrated with the timing technique. Initial results of gamma ray measurements showed a significant reduction in the background. However, losses did occur with the generation of the timing signals, which was improved with the use of a Timing Single Channel Analyser TSCA. The timing method has also been used to measure aluminium in a hand phantom. Unlike some other techniques for measuring aluminium in bone, this technique eliminates the possible interference usually encountered with the presence of phosphorus. The minimum detection limit obtained with the use of the timing showed a significant improvement to that without the timing technique. Further improvements and optimising of the system to higher detection efficiency of the gamma rays have been considered. A detection limit of about 5 mg of aluminium in the hand for a dose of 10 mSv is achievable with the improved system.

This thesis is concerned with the development and application of the technique of Laser Induced Breakdown Spectroscopy (LIBS) for remote materials analysis. Much of the study was carried out with a specific practical application in mind, namely the analysis of ferrous samples in the hostile environment within the area of nuclear reactors. Thus simplicity, manoeuvrability, and ease of use were important considerations in the research. For these reasons, an investigation into the use of a fibre optic as a compact, easy to handle means of laser delivery was undertaken, and all spectroscopic measurements were made with samples in air at normal atmospheric pressure. The investigation into the use of a fibre optic for laser beam delivery involved the design, building and assessment of two laser beam delivery systems. The first system, which utilised a Galilean telescope to produce a divergent beam for coupling to the fibre, was found to be unsuitable for transmitting the laser pulse energies required to produce plasmas suitable for LIBS. The second system, which was successfully used as part of a remote LIBS system, provided a divergent beam for coupling to the fibre. The proposed use of this system in hostile environments within nuclear reactor buildings, restricted the choice of fibre used to those which possess a good degree of radiation resistance. A similar fibre optic system was utilised for collecting and delivering a portion of the laser produced plasma emission to the spectrometer for analysis. In recent years there has been a considerable amount of research into the application of LIBS to the analysis of materials in buffer gas environments. Our research, however, assesses the potential of the remote LIBS technique for the analysis of materials under normal atmospheric conditions, since the application of a low pressure buffer gas environment is often impracticable for the <i>in situ</i> analysis of materials. One of the main aims of the LIBS experiments was the production of calibration curves, utilising spectroscopic standard steel and iron samples, for trace elements commonly found in ferrous materials. Measurements were made to gain an insight into the temporal evolution of the spectroscopic emission from plasmas, produced by ablating ferrous materials with laser radiation, to determine suitable 'time windows' for recording spectra to be used in the production of calibration curves. Calibration curves were produced for chromium, manganese, molybdenum, nickel, vanadium, and silicon, utilising iron as the reference element in relative intensity and concentration ratios, and also for manganese, nickel, vanadium and silicon, utilising chromium as the reference element. Estimates were made of the detection limits for each of these elements.

This thesis describes the development of a prototype orthogonal acceleration time-of-flight mass spectrometer, constructed at Swansea University (2002). This instrument incorporated design features to improve the duty-cycle of the time-of-flight mass spectrometer and was designed to conduct MS and MS/MS. Ion optical interfaces for full-beam transmission and collision-induced dissociation were developed. This work characterises the transport efficiency of the interfaces with a SCIEX electrosprayer. Ion transmission was dependent on the ion optical configuration, lens voltages, orifice sizes and stagnation pressure. Due to time limitations the full instrument was not completed and experimental work finalised on a commercial time-of-flight. A study of the ion structure of C₄H₄⁺ was carried out. A new method relying on consecutive reactions for controlling the internal energy of ions was used. Collision induced dissociation spectra of C₄H₄⁺ allowed the composition of the ion beam to be monitored and the vinylacetylene and methylenecylcopropene structures dominated. An observation was made for the fragmentation C₄H₄⁺ ® C₃^+., C₃H₁⁺, C₃H₂⁺ and C₃H₃⁺ for C₄H₄^+. formed in the ion source, compared to C₄H₄⁺formed in a field-free region. Their collision-induced dissociation mass-analysed ion kinetic energy (CID-MIKE) spectra were very different, which could not be accounted for in terms of structural and possibly internal energy differences. This is a highly reproducible effect requiring further study. Matrix-assisted laser desorption/ionisation (MALDI) was used on a ‘Voyager-DE STR’ to develop a survey technique analysis of nucleotides. The matrix α-cyano-4-hydroxyxinnamic acid matrix provided good sensitivity (<10pmol). MALDI as a quantitative tool was investigated. There are major challenges to overcome before MALDI can be reliably used for quantitation of nucleotides. An experimental survey of over 900 accurate mass measurements was made on 10 compounds and showed that accurate masses could be reliably obtained for 40% of adenosine monoshosphate samples but for quanosine di- and triphosphates this fell to near zero.