[en] Harmonic cavities have been used in storage rings to increase beam lifetime and Landau damping by lengthening the bunch.The need for lifetime increase is particularly great in the present generation of low to medium energy synchrotron light sources where the small transverse beam sizes lead to relatively short lifetimes from large-angle intrabeam (Touschek) scattering. We review the beam dynamics of harmonic radiofrequency (RF) systems and discuss optimization of the beam lifetime using passive harmonic cavities

[en] This study addresses whether fractionation of low LET (^-137 Cs γ rays) and high LET (²⁴¹Am α-particles) result in reduced, unaltered or enhanced changes in the frequencies of oncogenic transformations in mouse 3T3 cells. The RBE of α- versus γ-irradiation was found to be about 3 and for both, dose fractionation results in a reduced transformation incidence both for log-phase proiferating and plateau-phase (G₁) cells. Fractionating high LET (α-particle) irradiations did not result in enhanced effects in the 3T3 cell system at the doses employed

[en] We report on the design and commissioning of passive third harmonic cavities that have been installed in BESSY-II, a third generation high brightness synchrotron light source. Four cavities were installed to lengthen the electron bunches and increase the beam lifetime which is dominated by large angle intrabeam (Touschek) scattering. During routine user operation the system is running stable in a low power mode resulting in a current dependent bunch lengthening of up to a factor of 1.4, resulting in a significant improvement of beam lifetime. We also observed longitudinal stabilization of the beam using the cavities without the use of longitudinal feedback

[en] We report on the commissioning of a higher harmonic RF system designed to improve the Touschek lifetime of the Advanced Light Source. In our best results, we have achieved over a factor of two increase in the beam lifetime. Transient beam loading of the harmonic cavities by unequal fill patterns presents the greatest limitations on lifetime improvement. We also describe several interesting effects of the harmonic cavities on the operation of the longitudinal and transverse multibunch feedback systems

[en] We report on the commissioning of a higher harmonic radiofrequency system at the Advanced Light Source, designed to improve the beam lifetime. We have achieved an increase above a factor of two in our best results up to now. Transient beam loading of the harmonic cavities, due to the unequal fill patterns, creates the greatest limitation on lifetime improvement. We also describe several interesting effects on the operation of the longitudinal and transverse multibunch feedback system

No abstract available

[en] A grazing-incidence grating spectrometer has been used for the investigation of the undulator radiation from beamline 411 at MAX-lab. The direct detection of undulator light is expected to obtain the information of the quality of the undulator. Regular undulator radiation and some higher harmonics were observed. The effects of electronic beam coupling and Landau cavities have been studied. The experiment presents an easy and quick method to characterize the undulator radiation before the permanent monochromator is installed. (author)