Thesis (Ph.D)--Mechanical Engineering, Georgia Institute of Technology, 2010. / Committee Co-Chair: Hertel, Nolan; Committee Co-Chair: Kahn, Bernd; Committee Member: Kulp, David; Committee Member: Lee, Eva; Committee Member: Wang, Chris. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis--K obenhavns universitet. / Bibliography: p. [122]-124.

Proefschrift--Utrecht. / "References": p. [87]-88.

Thesis--K obenhavns universitet. / Bibliography: p. [122]-124.

Proefschrift--Utrecht. / "References": p. [87]-88.

A semicircular focussing spectrometer has been built to examine beta spectra in the energy range below 100 Kev. The detection of the beta particles is accomplished by means of Geiger counters filled with the saturated vapor of liquid heptane (C₇H₁₆) kept in a bath of melting ice. The windows of the counters are made from thin films of zapon about 5 to 8 micrograms/cm² in thickness. The sources are mounted on similar films approximately 10 micrograms/cm² and have an average total thickness of the order of 30 micrograms/cm² . The combination of thin source and thin windows enables measurements of spectra to be made down to an energy of 2 Kev. An examination of the beta spectrum of RaD (₈₂Pb²¹⁰) with the spectrometer has been carried out. It consists of L, M and N conversion lines of a 47 Kev. gamma ray, a peak at about 3 Kev assigned to conversion of a 7.7 Kev gamma in the M shell of the atom, and a primary beta spectrum. A Kurie plot of the primary beta spectrum yields an end point of 21.7 Kev. In addition there are two weak conversion lines at 18 and 21 Kev which are tentatively assigned to the L conversion of gamma rays of 34 and 37 Kev. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

PART 1 A new method has been used to suppress the undesirable Compton electrons ordinarily present in photoelectron spectra. As much as 90% of the Compton electron intensity was removed. This was accomplished by electronic cancellation of the individual Compton electrons. The method has been used with a thin lens type of spectrometer and has made possible the detection of new gamma rays at .391, .857 and 1.00 Mev. in Ra(B + C), at 1.01 Mev. in Ta¹⁸², and at .472 and .843 Mev. In Sb¹²⁴. No.new gamma rays were observed from Co⁶⁰. PART 2 A search for double beta decay in Sn¹²⁴ has been made using a coincidence technique particularly suited to double beta decay under the Majorana form of neutrino theory. Negative results were obtained and a lower limit of 0.3 - 0.7 x 10¹⁷ years has been set on the half-life of the process. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

An intermediate image beta ray spectrometer has been constructed using the two magnets from two thin lens spectrometers, previously in use in this laboratory. A surface barrier type detector replaces the scintillator -photomultiplier arrangement used before, resulting in greatly reduced background noise. The performance of this spectrometer is considerably better than the two it replaces, having resolutions of 0.51 %, 0.7 %, 0.94 % and 2.2 % at transmissions of 0.49 %, 0.96 %, 1.26 % and 5.96 %. The normal energy range is from 25 Kev, to 1.5 Mev but it can be extended to 2.0 Mev with some loss of transmission. An examination of the beta spectrum of Eu¹⁵⁴ was carried out with this instrument. A Kurie plot of the continuum has been made and six primary beta groups found with end point energies of 1.866 Mev, 1.198 Mev , 0.976 Mev , 0.843 Mev , 0.579 Mev , and 0.274 Mev with relative abundances of 10.8 %. 0.67 %, 4.6 %, 17.0 %, 37.8 %, and 29.1 %. Both end-points and relative intensities are in excellent agreement with data from other workers. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Call number: LD2668 .T4 1959 M87

No description available.