A CROWBARLESS HIGH VOLTAGE POWER CONVERTER FOR RF KLYSTRONS
Advances in power electronic components make feasible the production of switch-mode power converters in module sizes exceeding 100kW. The development of a power converter system in modular form for feeding high power CW RF klystrons will be described. It has the advantage that the stored energy at high voltage is so small that the conventional crowbar protection is unnecessary. Results of work to test the principle on a 50kW klystron used for power testing accelerating cavities at Daresbury will be presented.
New Magnet Power Converters for the SRS at Daresbury
A programme to replace 25 year old magnet power converters on the SRS at Daresbury is nearing completion. The roller regulator converters recovered from the NINA synchrotron beamlines are being replaced by commercially available switch-mode units for those rated up to lOkW, and by thyristor phase controlled units for those rated from 90kW to 750kW. The latter are designed to the CERN LEP standards, and incorporate the LEP control electronics. Some minor changes to the microprocessor software were made to facilitate interfacing to the SRS control system.
Nursing theory and administrative practice: Agenda for the 1990s
&NA; Despite past progress in the development of nursing theory, a theoretical nursing perspective is not yet common to the practice of nursing administration. Such a perspective could serve as a catalyst both to advance knowledge development for administrative nursing practice and to align clinical and administrative practice within a common framework. In this article assumptions, concepts, and questions common to both clinical and administrative nursing practice are identified. Select domain concepts are used to exemplify the themes shared by nurse clinicians and nurse administrators. The article concludes with a five‐item agenda as a guide for future theory development.