Abstract
The research carried out on the stabilization control and protection of two Van de Graaff electrostatic nuclear accelerators is described in this thesis. The system at Oxford consists of a single ended and a tandem accelerator with two different kinds of stabilizers; the results presented here are directly applicable to most electrostatic accelerators. As an end result of the mathematical analysis, the behaviour of the single ended injector with combined liner and spray control is formulated. The stabilizer designed for the injector, based on the analysis, incorporates automatic switch over to the auxiliary generating voltmeter stabilizer loop. The automatic gain control introduced into the slit amplifiers eliminates the necessity of manual gain adjustments for different operating conditions. The energy resolution of the injector was measured by using alpha capture resonance in [15]N. It was 0.65 keV at 4.46 MeV. The analysis presented here describes the behaviour of the corona stabilizer as used on the tandem. The predicted limitations due to the time delay and dispersion of the ions in high pressure gas are in good agreement with the measured performance figures. The two loop stabilizer with the auxiliary generating voltmeter loop provides facilities for semi-automatic operation. The resolution of the tandem was +/-1 keV by measuring the [28]Si(p,p)[28]Si resonance at 5.83 MeV. Multiple breakdowns on both the injector and the tandem were prevented by the introduction of the protection circuit. The circuit design was based on the analysis of the breakdown behaviour of the generators as described. The predicted performance of the circuit and its effect on the accelerators is well verified by the observed behaviour of the generators after total breakdown. The study of the computer controlled generator operation is described in Chapter 5. For the interfacing the internationally accepted Camac system is recommended.