This thesis is concerned with tolerances for magnetic field imperfections in the TRIUMF cyclotron set by the betatron oscillation resonances v[formula omitted] = 1.0, v[formula omitted] – v[formula omitted] = 1.0 and v[formula omitted] = 1.5. These resonances, encountered during acceleration, can lead to undesirable growth in the amplitudes of the betatron oscillations. We first derive equations of motion that take into account non-linear terms and field imperfections, and show how resonance conditions may occur. These conditions were simulated in our orbit codes and numerical calculations were made to determine the tolerances they impose on the magnetic field. We have made a detailed investigation of the effect on the behaviour of the beam of first harmonic bumps at radii less than 150 in. The first harmonic tolerance of 0.1 G to produce an increase in the radial amplitude of 0.1 in. is in agreement with analytical calculations. We have also shown that this tolerance, too small to be seen in the magnetic field survey, may be achieved by suitable adjustments in the harmonic coil settings. Tolerances on the second harmonic imperfection are also presented. To determine the tolerances set by the coupled resonance v[formula omitted] – v[formula omitted] = 1.0, we have simulated a first harmonic twist in the median plane. The results show that, for high current poor resolution experiments, the magnitude of the twist on entering the resonance is of no importance, provided the amplitudes of the radial and vertical betatron oscillations are not much larger than the estimate of 0.2 in. For high resolution experiments, the tolerances on the slope of the twist are of the order of a few mrad. Analytical estimates of these tolerances are also presented. Finally, we have determined that the v[formula omitted] = 1.5 resonance sets an upper limit to the gradient of the third harmonic of about 0.2 G/in., which produces a 20% increase in the radial betatron amplitude. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

An analysis of the most commonly used type of Ion Cyclotron Resonance (ICR) spectrometer is given. Though the equations of motion of an isolated ion in the ICR geometry are extremely non-linear, it was found possible to decouple the longtitudinal oscillations due to the trapping potential from the cyclotron motion by exploiting the fact that the cyclotron frequency is very much greater than the trapping frequency. A previously unsuspected dependence of the cyclotron frequency and drift velocity of an ion on its spatial coordinates was discovered and experimentally investigated. The distribution of energies for ions at resonance with an applied r-f electric field is also discussed and improved techniques for the study of energy dependent cross-sections are proposed. Conventional ICR techniques were used to estimate collision frequencies of sodium and potassium ions in helium and argon gases. These experiments yield information about the d.c. drift mobility, in the zero field limit, of the alkali ions in inert gases and are discussed in terms of various models of the ion-atom interaction potential. A crossed beam arrangement was used to obtain preliminary estimates of low energy rate constants for both asymmetric and symmetric resonant charge transfer between alkali ion-atom pairs. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

A comparison is made between the experimental and theoretical behaviour of the H" beam in the TRIUMF central region cyclotron. The axial injection process and the first six accelerated turns are studied in detail. In order to optimize the cyclotron performance the phase space emittance of the beam at the injection line exit must be matched to the central region acceptances. To this end,a theoretical study was made of the ion optical properties of the injection elements: the magnet bore, the spiral electrostatic inflector, the electrostatic deflector and the first radio-frequency accelerating gap. In many cases these results were confirmed by experimental observations. It was also shown theoretically that by a suitable choice of the accelerating gap, under optimum conditions, 10% of the injected beam can be directed within the radial acceptance and 30% within the vertical acceptances. The effects of a chopper and buncher in the injection line were also measured. A minimum pulse length of approximately 2.5 nsec was obtained with a bunching factor of 3-0. To accelerate a beam to full radius, vertical steering had at first to be provided by means of asymmetrically-powered trim coils and electrostatic deflection plates for each turn. The steering required is known to be consistent with the effects of magnetic field asymmetries and dee misalignments measured later. The size and shape of the vertical beam envelopes were found to be consistent with theory. The vertical tune vz was estimated to be 0.17 ± 0.03 for 20 deg phase ions. This agreed with the predicted value of 0.17- The transition phase which separates the vertically-focused and defocused phases was estimated to be -3 ± 3 deg, while the predicted value was 0 deg. The radial beam diagnostic techniques used for determining proper centring and isochronous operating conditions are discussed. With these techniques it was possible to centre a 30 deg phase interval to within 0.15 in., which was the approximate uncertainty in our measurements. A simplified treatment of radia 1 - longitudinal coupling is given and used to explain qualitatively the behaviour of a small emittance beam. The effects of space charge on the first six accelerated turns are calculated. For a beam occupying a phase width of 30 deg, these effects are predicted to be negligible for average accelerated currents below 100 uA. The experimental observations made on high-current beams are described.; prior to the shutdown of the cyclotron beams of up to 1^0 uA average current were accelerated. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Thesis (Ph. D.)--University of Wisconsin--Madison, 1965. / Typescript. Abstracted in Dissertation abstracts, v. 25 (1965) no. 10, p. 6020. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

An ELF noise band observed by the Alouette II satellite has been studied. A digital power spectrum program was set up in order to investigate in detail the noise band spectra. Primary results from this analysis are that: a) for altitudes 500-3000 Km. and all geomagnetic latitudes, sharp lower cutoffs of the noise band occur within ~30Hz of the calculated gyrofrequency, b) upper cutoffs to the noise band occur frequently near harmonics of the gyrofrequency, and c) the noise appears to be Doppler shifted when the angle between the velocity vector of the satellite and the geomagnetic field is near 90°. The occurrence pattern of the noise band has been investigated using available Rayspan analyzed data for epoch 1966. This analysis indicated a pronounced daytime maximum of occurrence. It is shown that almost all aspects of the noise band may be interpreted in terms of the hypothesis of ambient electrostatic proton cyclotron harmonic waves in the ionosphere, and the concomitant accessibility conditions in the spatially varying geomagnetic field. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Foram desenvolvidos modelos analíticos que descrevem os elementos básicos para irradiações de alvos metálicos em ciclotrons. Parâmetros importantes como valor máximo de corrente de feixe e potência térmica depositada sobre o alvo foram obtidos e confrontados com situações práticas. De forma totalmente inédita, foram determinados analiticamente as características encontradas em situações de intensos transientes térmicos, quando altas concentrações de prótons em uma pequena região do feixe provocam intensos gradientes de temperatura em pequenas regiões do alvo. A comparação dos resultados obtidos com aqueles encontrados na literatura mostraram que os modelos desenvolvidos são satisfatórios, tendo em vista todas as limitações do modelo proposto. / Analytical models were developed that describe the basic elements for metal targets irradiation in cyclotrons. Important parameters such as maximum beam current value and thermal power deposited on target were obtained and compared with practical situations. In an unprecedented way, were determined analytically the features found in intense thermal transient situations, when high protons concentrations in a small region of the beam cause intense temperature gradients in small regions of the target. Comparing with results found in the literature showed that the developed models are satisfactory, in view of all limitations of the proposed model.

Foram desenvolvidos modelos analíticos que descrevem os elementos básicos para irradiações de alvos metálicos em ciclotrons. Parâmetros importantes como valor máximo de corrente de feixe e potência térmica depositada sobre o alvo foram obtidos e confrontados com situações práticas. De forma totalmente inédita, foram determinados analiticamente as características encontradas em situações de intensos transientes térmicos, quando altas concentrações de prótons em uma pequena região do feixe provocam intensos gradientes de temperatura em pequenas regiões do alvo. A comparação dos resultados obtidos com aqueles encontrados na literatura mostraram que os modelos desenvolvidos são satisfatórios, tendo em vista todas as limitações do modelo proposto. / Analytical models were developed that describe the basic elements for metal targets irradiation in cyclotrons. Important parameters such as maximum beam current value and thermal power deposited on target were obtained and compared with practical situations. In an unprecedented way, were determined analytically the features found in intense thermal transient situations, when high protons concentrations in a small region of the beam cause intense temperature gradients in small regions of the target. Comparing with results found in the literature showed that the developed models are satisfactory, in view of all limitations of the proposed model.

"October 30, 1947." / Army Signal Corps Contract No. W-36-039 sc-32037.

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Introduction When properly maintained, cyclotrons often remain in operation for 20 years and more. However, as the years pass the control systems in particular become challenging to support. The I/O cards and other hardware eventually become obsolete, making spare parts difficult or even impossible to find. And the knowledge and ability to reload and configure the software also gets lost as operating systems and media storage technology change. This obsolescence is true of the Siemens RDS-112 cyclotron, which is controlled using a 486 computer, connected to an external STD card rack containing up to 15 I/O cards. These I/O cards were last manufactured in the 1990’s, and the iRMX-based control programs malfunction on computers newer than a 486 processor. A control system upgrade for the RDS-112 cyclotron has been developed by PET Technical Consulting Inc. This commercially available control system reduces operator training time, requires less maintenance, and supports new targets and custom product processes. Material and Methods The availability of high channel count I/O cards, and the decision not to support the old CPCU synthesis units, means the entire STD card rack can be replaced with 5 National Instruments (NI) I/O cards. The replacement computer is an industrial grade rack mounted PC with RAID 1 mirrored pair hard drives in front panel access quick swap bays. Two NI PCI-6509 Digital I/O cards connect directly to the RDS electronics, channel assignments are mapped using software configuration. Three NI PCI-6229 Multifunction I/O cards connect to the RDS electronics through a cable breakout interface plate, the terminal blocks are wired as needed to map the channels. The new control software was created using National Instruments LabVIEW. The new control sequences have a core based on the original RDS-112 FORTRAN control programs. Then hundreds of improvements were made to simplify operation, increase flexibility, minimize user involvement and mistakes, and clearly display key parameters and fault conditions. System control has been combined into a comprehensive Graphical User Interface, with controls and indicators grouped together onto subsystem pages. Commands that once needed to be typed-in have been replaced with a clickable control for each function. Bar graphs display target and slit currents. Status is obvious with red faults against normally green indicators. Audio alarms cue the operator for process interaction, warn if target current or pressure drifts from setpoint, or if faults occur with power supplies, vacuum, or water cooling. Improvements in sequences and beam algorithms have reduced the time to achieve full beam on dual targets from 10 minutes down to 3 minutes. Results and Conclusion This new control system has been installed on (5) five RDS-112 cyclotrons used for commercial isotope distribution. The total combined operation time of these systems after receiving the upgrade is now over 17 years, during this time the control system operation has been nearly problem free. UPDATE: The Siemens RDS-111 cyclotron is controlled by a VME computer that is now end-of-life. The VM30 and VM42 CPU boards and many of the I/O modules are no longer manu-factured. PET Technical Consulting is developing a control system replacement for the RDS-111 cyclotron with expected completion in 2014.