No abstract available

[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] The influence of high-order terms of momentum compaction factor on beam longitudinal oscillations in electron storage rings is studied. It is shown that nonlinear terms lead to separatrix distortion and as a result to the beam lifetime reduction. The obtained results are applied for calculation of beam real lifetime in the CANDLE(accelerator)storage ring

[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

No abstract available

[en] A relativistic electron ring moving along a conducting wall is acted on by a retarding force due to the ohmic losses of the image currents in the wall. This force is calculated for an electron ring moving coaxially along a cylinder of arbitrary thickness. The dependence of the force on the thickness and conductivity of the cylinder and on the ring velocity is discussed. (author)

No abstract available

No abstract available

[en] The description of the method for determination of electron ring loading with ions at the JINR electron-ring accelerator prototype is given. The method is based on the detection of high frequency oscillations related to radial coherent dipole oscillations of electron-ion ring. The estimation of the loading factor in the case of ring compression in the adhesator with reSidUal gas at the pressure of 10^-7 torr is 45. With the number of electrons of 5x10¹² the number of ions is estimated as 2x10¹¹