We investigate the upgrade of Elettra 2.0 to radio-frequency transverse deflecting cavities generating a steady-state vertical deflection of selected electron bunches. The study demonstrates the feasibility of 1 to few ps-long x-ray pulses at MHz repetition rate provided simultaneously to several beamlines, and transparent to the standard multi-bunch operation. The short pulse exhibits total flux at 1-10% level of the standard single bunch emission, and transverse coherence preserved in both transverse planes up to approximately 0.5 keV.

An upgrade project is ongoing at Elettra Sincrotrone Trieste for a 4th-generation storage ring light source called Elettra 2.0. The new machine poses new challenges in terms of performance of the accelerator and sub-systems. One concern, currently under investigation, is about the effects of the passive superconducting third harmonic cavity on the stored beam due to the presence of a dark gap in the beam filling pattern. A simulator based on an analytical frequency-domain model was developed to evaluate the variation of the synchronous phase and synchrotron frequency along the bunch train, as well as the distortion of the bunch profile. Experiments have been carried out in the present Elettra storage ring to characterize the harmonic cavity and to measure the ef-fect of transient beam loading by using the longitudinal multi-bunch feedback system. An ongoing benchmarking of the model and experimental results is reported.

The accurate analysis of any possible source of beam instability is mandatory for the design of a new particle accelerator, especially for high current and ultra low emittance synchrotrons. In the specific case of instabilities driven by the coupling between the charged particle beam and the electromagnetic field excited by the beam itself, the corresponding effect is estimated through the beam coupling impedance. The modeling of this effect is fundamental to perform a rigorous evaluation of the coupling impedance budget able to account for all devices present in the entire machine. To deal with this problem, this paper focuses on the estimation of the contribution of the joints lying between the different vacuum chamber sections, by performing a comparative numerical analysis that takes into account for different aperture gaps between the flanges. The results point out the criticality of many small-impedance contributions that, added together, must be lower than a predefined impedance threshold.

Beam position monitors (BPMs) are fundamental diagnostic tools for lightsources: thanks to their data readout, machine orbit can be stabilized and corrected by control systems. New generation machines need better performances on these diagnostic devices due to increased demands, such as smaller photon beam size and long-term stability. This article outlines all the devices that will make up the future Elettra 2.0 BPM system, based on pilot tone compensation. The entire signal acquisition chain will be described, from the pickups to data delivery to the control system. After a brief introduction about the electronics (analog signal conditioning, digital conversion and processing), more emphasis will be given to the description of timing and synchronization functionalities, machine protection system integration and machine feedback

Diffraction Limited Storage Rings, the 4th generation machines, provide transversely coherent beams with uniform phase, maintaining high photons flux and stability. Diagnostic systems play an essential role for both commissioning and operating tasks of Elettra 2.0. The small beam dimensions make measurements of both position and size challenging. Elettra 2.0 diagnostics will rely mainly on Beam Position Monitors and Synchrotron Radiation Profile Measurements. In this paper, an overview of all the beam diagnostics that will equip the new storage ring will be given, along with the diagnostic systems involved in the main machine control.

In order to fulfill the target performance of Elettra 2.0 light source, a brand new button type beam position monitor detector has been developed. From a theoretical point of view, the transfer function which relates beam position information to electromagnetic signal intensity induced on pick up electrodes is well known. In practice, due to a number of constraints, a real device implementing this transfer function is difficult to manufacture. In this paper, a series of practical design considerations involving electromagnetic, mechanical, vacuum, maintenance, and cost issues are reported to illustrate the advantages and disadvantages of the conceived constructive solutions.