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[en] The development of superconducting cavity resonators for the CESR II, PETRA, DORIS, TRISTAN, and LEP storage rings is described. (HSI).

[en] Since the fast transverse instability was observed in PETRA and, more recently, in PEP, this instability has become a critical problem in the design of large storage rings. The reason is that this instability imposes the serious limitation on a stored current; as soon as the current exceeds the threshold, the bunch distribution begins to blow up vertically or horizontally more rapidly that the synchrotron oscillation, and beam particles are lost. Short range fields created by the beam in RF cavities are considered to play an important role. The fast instability has been explained in terms of mode coupling in the longitudinal phase space or head-tail turbulence by other authors. The purpose of this paper is to derive a formalism of the mode coupling theory for a Gaussian bunch beginning from Sacherer's integral equation. The problem is reduced to solving the determinant equation for eigenfrequencies of coherent oscillations. Eigenfunctions are expressed as superposition of the linear independent functions where higher radial modes and azimuthal modes are combined and rearranged into ''hybrid'' modes. The theory is applied to explaining the fast instability observed in PEP and to a preliminary estimate of the threshold current in the TRISTAN electron-positron storage ring. The transverse broad-band impedances of RF cavities in PEP and TRISTAN are calculated with the program code TBCI and characterized by a single low-Q resonator impedance. A satisfactory agreement with PEP experimental results is obtained

[en] While both accelerators and digital computers have existed for more than forty years, it was not until the mid seventies that they were successfully united to form the computerized accelerators that are standard today. When the first mini-computers became available circa 1965 they were immediately employed at accelerator sites - for experiments. The physicists were very quick to put them to use in spite of their deficiencies: assembler programming, no operating system to speak of, and limited reliability. Controls people were sure that they did not need them and agreed that knobs and dials were the ''natural'' interface between men and machines anyhow. Also, a potentiometer setting was far cheaper and more reliable than a value in core storage plus its associated ADC. Nevertheless, computers started creeping into control systems, took over the tedious tasks such as setting magnet currents and logging them, but always on a two-ported basis via an added connector guarded by that little switch that enabled good old manual control. Of course, computer breakdowns were entered into logbooks besides traditional obstacles such as water leaks or power supply failures. Today we know that computers wouldn't become reliable until people decided to rely on them

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[en] Observations of the beam-beam interaction at SPEAR, CESR, PETRA and PEP are discussed. They are sufficiently similar that a simple prescription can be formulated to describe the behavior of the luminosity as a function of current including the peak values. With this prescription the interpretation of various methods of increasing the luminosity, such as the reduction of the vertical betatron function, the increase of the horizontal beam size, and mini- and micro- beta projects, is straight-forward. Predictions for future storage rings can also be made. Finally, some observations of the consequences of reducing the vertical betatron function to near the value of the bunch length are discussed