[en] In the early days of cyclic RF accelerators the number of particles orbiting inside the machine was so small that the RF accelerating system was the least expensive and the most simple part of the machine. Less than twenty years later the situation was very much changed and now the opposite is true. The intensity of the accelerated current is so high and the required performances are so high that the RF accelerating systems are now a very sophisticated and expensive part of the whole machine. Moreover, it should be added that the major limitations to the possibility of an orbital machine now only come from the RF system. The same applies to linear accelerators where the machine itself is (as it was at the beginning) an RF device. Again at the dawn of the electromagnetic accelerators the linear accelerator was a small RF system with a very limited task. Now a tremendous effort is being made around the world to increase the fields and the intensity of the accelerated beam and this is generating a family of linear accelerators of increasing cost and complexity. 7 references, 35 figures, 1 table

[en] After a survey of the state variable analysis method the final amplifier for the CBA is analyzed taking into account the real beam waveshape. An empirical method for checking the stability of a non-linear system is also considered

[en] In contrast to the early days of cyclic and linear RF accelerators, modern high beam currents and performance parameters require very sophisticated and expensive RF accelerating systems. This work is a schematic presentation of current RF acceleration technology. Because of time limitations this treatment will be based simply on drawings and schematic comments

[en] The need of very low output impedance rf systems for heavy particle accelerators has led to the development of very sophisticated amplifier configurations. Among them, the use of a common-anode final amplifier seems most promising. If the output impedance is defined in the Thevenin Theorem sense, then class-A operation seems unavoidable. However, for particle dynamics only the voltage induced by the beam is of real concern and voltage requirements do not necessarily demand a time invariant output impedance. These considerations led to investigation of the conditions that must be met to obtain control over the beam-induced voltage. It was possible to demonstrate that in the common anode case the induced voltage can be largely independent of the bias applied to the final tube, if the beam loading is very strong

[en] It is shown that the negative real part of an input impedance does not mean instability of the related circuit. A negative real part of the input impedance means only that the concerned circuit is active

[en] The design of a conventional RF system is always complex and must fit the needs of the particular machine for which it is planned. It follows that many different design criteria should be considered and analyzed, thus exceeding the narrow limits of a lecture. For this reason only the fundamental components of an RF system, including the generators, are considered in this short seminar. The most common formulas are simply presented in the text, while their derivations are shown in the appendices to facilitate, if desired, a more advanced level of understanding. (orig.)

[en] The need for a very low final amplifier output impedance, always associated with class A operation, requires a very large power waste in the final tube. The recently suggested pulsed rf operation, while saving a large amount of power, increases the inherent final amplifier non linearity. A method is presented for avoiding the large signal non linear analysis and it is shown how each component of the beam induced voltage depends upon all the beam harmonics via some coupling coefficients which are evaluated

[en] In circular accelerators and particularly in storage rings it is essential that the total impedance, as seen by the beam, be kept below some critical value. A model of the accelerating system was built using a single-ended cathode-follower amplifier driving a ferrite-loaded cavity. The system operated at 234.5 kHz with a peak output voltage of +-10 kV on the gap. The dynamic output impedance, as measured on the gap, was < 15 ohms

[en] ELETTRA, the 3rd generation synchrotron radiation source under construction in Trieste has passed the design phase. The present schedule calls for a start of commissioning by the second half of 1993. The buildings are under construction and prototypes for all main components of the accelerator complex have been constructed and industrial production has started. A high power cavity fully equipped with cooling circuit and input coupling loop, as well as mechanical tuning system, has been tested and measured. Prototype cavities equipped with higher order mode suppressors are under development. In-house prototypes for each magnet type have been built and magnetic measurements have been performed. The vacuum chamber prototype has been baked under vacuum and tested with its pumping system. A prototype pure permanent magnet undulator has been assembled and measured. The first 100 MeV sections of the 1.5 GeV injection linac will go in operation in August 1990

[en] After a survey of the state variable analysis method the final amplifier for the CBA is analyzed taking into account the real beam waveshape. An empirical method for checking the stability of a non linear system is also considered