The increasing importance of narrow-band radiations is traced in the recent history of radio astronomy. The need for multi-channel spectrometers to observe these radiations is stressed. The theoretical basis of spectral analysis is given with particular emphasis on autocorrelation or interference methods. A twenty-channel radio-frequency spectrometer designed on interference principles has been constructed and found to perform in accordance with its theory of operation. When used in conjunction with a 25-metre telescope and a hydrogen receiver the spectrometer is capable of producing low-noise wideband spectra at high speed. The spectrometer output was recorded on punched cards, and subsequent data processing was by digital methods. A large area including the position of the spiral galaxy M31 was surveyed with the help of the spectrometer. One hundred and forty-three independent spectra of the 21-cm radiation of atomic hydrogen were obtained and are analyzed in terms of area, velocity, and shape. The major axis of the nebula is found to extend about 2.5° either side of the centre, in agreement with the work of van de Hulst, Raimond, and van Woerden (1957). The length of the minor axis, after correction for the effect of the antenna beamwidth, is only 40', a result which indicates a reduction in the inclination (of the plane of the galaxy to the line of sight) from 14.5° to 8.2°. This lower value leads to an upward revision of the optical axial ratio (of galactic thickness to galactic diameter) to 0.2, while maintaining a low ratio (0.07, Schmidt, 1957) for the distribution of atomic hydrogen. A high axial ratio would clear the way for a reinterpretation of the optical velocities of emission nebulae in M31 (Mayall, 1950), which have so far appeared to be in violent contradiction to the radio velocities (van de Hulst et al, 1957). It is suggested that many of these emission objects may lie some distance from the plane of the galaxy. The position angle of M31, as revealed by the spectrometer observations is distinctly less than the 38° established optically. A new value of 33° is proposed and it is suggested that the former value can be accounted for in terms of an increased axial ratio and the observed asymmetries in the light distribution. The velocity of the centre of gravity of M31 has been obtained by summation of all 143 spectra. The result, -295.6±0.4 km/sec with respect to the local standard of rest, is in complete agreement with that found by van de Hulst (ibid). Radial motions of a few km/sec are possible in the outer parts of M31 but their presence has not been established. Many of the spectra have multiple peaks, which may be interpreted in terms of spiral structure. The velocities of certain concentrations of atomic hydrogen are measurable but their positions are not resolved by the antenna beam. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

In 2010, comet 103P/Hartley 2 was observed pre- and post-perihelion using the George and Cynthia Mitchell Integral Field Spectrometer on the 2.7-m telescope at McDonald Observatory in Texas. Data for gaseous radicals C2, C3, CH, CN, and NH2 were collected over six nights from 15 July to 10 November. The spectral data were used to create coma maps for each of the observed species, and the maps were processed using radial and azimuthal mean division techniques to create enhanced images of the coma, revealing subtle morphological features. 340 enhanced coma images were created for each observation and species. Visual inspection reveals that the coma is heterogeneous between the five detected radicals, and statistical analyses verify this result. To compliment the ongoing investigation of Hartley 2 as studied by the EPOXI flyby mission, findings from other researchers (Belton et al., 2012; Syal et al., 2012; and Thomas et al., 2012) are used to characterize the nucleus spin state and identify dust jet locations on the nucleus. With rotational period measurements from EPOXI, dust jet vectors on the nucleus surface are rotated to relevant observation times in November to compare the computed jet directions with the radical densities in the coma. Dust jet sites on the smaller nucleus lobe show a stronger correlation with high radical concentrations than the dust sites on the larger nucleus lobe. Production rates for potential parentage of radical species are calculated using the radial outflow Haser model (Haser, 1957), which are compared to mixing ratios relative to water from separate campaigns to constrain parentage. NH3 is likely the sole producer of NH2, whereas CN may be produced from a combination of HCN, C2N2, and CH3CN. Traditional parentage of C2, C3, and CH do not yield acceptable fits or suitable mixing ratios with the Haser model, and it is possible that extended coma ices having relatively short scale lengths greatly contribute to production of these radicals. These results provide further evidence that the Hartley 2 nucleus is heterogeneous in composition, and the rotational analysis indicates that specific jet sites are correlated with certain radical species.

No description available.

The study of proteomics holds the hope for detecting serious diseases earlier than is currently possible by analyzing blood samples in a mass spectrometer. Unfortunately, the statistics involved in comparing a control group to a diseased group are not trivial, and these difficulties have led others to incorrect decisions in the past. This paper considers a nested design that was used to quantify and identify the sources of variation in the mass spectrometer at BYU, so that correct conclusions can be drawn from blood samples analyzed in proteomics. Algorithms were developed which detect, align, correct, and cluster the peaks in this experiment. The variation in the m/z values as well as the variation in the intensities was studied, and the nested nature of the design allowed us to estimate the sources of that variation. The variation due to the machine components, including the mass spectrometer itself, was much greater than the variation in the preprocessing steps. This conclusion inspires future studies to investigate which part of the machine steps is causing the most variation.

This thesis has been written to provide a basic understanding of the spectrometer and to be used as a useful reference for its operation. Discussions of such things as the propagation of microwaves and the mechanics of klystron operations have been avoided.

<p> The energy levels of Sm151 populated in the beta decay of Pm151 have been studied with the aid of magnetic spectrometers. The internal and external conversion spectra were examined with a π√2 spectrometer of 50 cm radius. A Gerholm-type double lens coincidence spectrometer was used to perform electron-beta, electron-electron, electron-gamma and gamma-beta coincidence experiments. In addition, precise measurements of the transition energies obtained by Geiger and Graham (1962) with the Chalk River π√2 iron-free spectrometer are included. A decay scheme based on these results is proposed and speculations are made concerning the possible interpretation of the levels on the basis of the Nilsson model. The results are also compared with other recently published data on this decay.</p> / Thesis / Doctor of Philosophy (PhD)

One of two Project Reports; Part A: http://hdl.handle.net/11375/17663 / No abstract provided / Thesis / Master of Engineering (ME)

No description available.

A single crystal neutron spectrometer using a copper crystal has been designed and constructed for the purpose of studying the low energy (<1 ev) neutron spectrum from the V.P.I. reactor. The basic theory necessary for the design, the details of the spectrometer, calibration data and method of operation are presented in this thesis. A relation between angle of diffraction and neutron energy is obtained from the known lattice spacing of the copper crystal. A measure of the total cross section of cadmium from 0.01 to 1.0 ev has been obtained from transmission data for a thin cadmium sheet. The position of the low energy resonance peak confirms the computed calibration. The resolution of the instrument and the intensity of the diffracted beam as a function of energy were studied in order to ascertain the usable range of the spectrometer. / Master of Science

This thesis is written in three sections; the first presents a critical survey of methods which have been used to measure magnetic fields; the second describes the construction of an A.C. null method capable of comparing two fields to one part in 30,000, and the third discusses its performance. / Thesis / Master of Science (MS)