The European Synchrotron Radiation Facility Extremely Brilliant Source (ESRF-EBS) is the first fourth generation 6 GeV storage ring (SR) light source making use of the hybrid multibend achromat lattice, reaching a natural horizontal emittance of 140 pm rad. Further, reducing the horizontal emittance would provide a more brilliant and a higher quality photon source for the EBS users. One way of achieving this is to operate the SR off-energy. The first approach reduces the electron beam energy by −1%, which gives a 121 pm rad natural horizontal emittance. To fulfill operation requirements, the full ring had to be rematched, including both the quadrupoles and the sextupoles in the linear optics correction. The off-energy settings are then tested in the SR in terms of lifetime, injection efficiency, and operability. Published by the American Physical Society 2024

Radia 3D magnetostatics code has been used for the design of insertion devices for light sources over more than two decades. The code uses the magnetization integral approach that is efficient for solving permanent magnet and hybrid magnet structures. The initial version of the Radia code was sequential, its core written in C++ and interface in the Mathematica language. This paper describes a new Python interfaced parallel version of Radia and its applications. The parallelization of the code was implemented on C++ level, where the semi-analytical calculations of interaction matrix elements and resultant magnetic fields were parallelized using the Message Passing Interface. The parallel performance results are encouraging, particularly for magnetic field calculation post relaxation where a ∼600 speedup with respect to sequential execution was obtained. The new parallel Radia version facilitates designs of insertion devices and lattice magnets for novel particle accelerators.

The European Synchrotron Radiation Facility Extremely Brilliant Source (ESRF-EBS) is a facility upgrade allowing its scientific users to take advantage of the first high-energy 4th generation light source. In December 2018, after 30 years of operation, the beam stopped for a 12-month shutdown to dismantle the old storage ring and to install the new X-ray source. In December 2019, first beam was stored and accumulated in the storage ring, allowing the vacuum conditioning and tuning to be started. Beam was delivered to beamlines in March 2020 for their commissioning. On 25 August, the user programme was restarted with beam parameters very close to nominal values. In this report the milestones and key aspects of the return to user-mode operation are presented and discussed.

The ESRF operates a 6 GeV 4th generation light source, the ESRF-EBS. This storage ring is the first to implement the Hybrid Multi-Bend Achromat lattice (HMBA). The HMBA lattice provides a reduction of the horizontal emittance of approximately a factor 30 with respect to the former Double Bend Achromat (DBA) structure, considerably improving the brilliance and transverse coherence of the ESRF accelerator complex while maintaining large horizontal acceptance and excellent lifetime performance. In this report, the characteristics of the HMBA lattice will be reviewed and the beam commissioning results and first operation experience of the new ESRF storage ring will be presented.

Since 25th August 2020 the new European Synchrotron Radiation Facility Extremely Brilliant Source (ESRF EBS) storage ring (Biasci et al., 2014 and Admans et al., 2014) [1], [2] has been providing beam to users in top-up mode with front-end (FE) shutters open. The obvious need to extract X-rays from the electron vacuum chamber generates a potential in-vacuum gate available to 6GeV electrons for reaching the beam-line hutches. This event represents a major radio-protection issue (Berkvens, 2020) [3]. We must thus assure that no electron will ever reach the beam-line hutches in the presence of stored beam with FE open. To this end, we performed a complete set of simulations to assess the safety of top-up injection including all possible scenarios.

Several new accelerator facilities will be built in Russia in few years from now. One of those facilities is a 6 GeV storage ring (SR) light source (USSR – Ultimate Source of Synchrotron Radiation) to be build in Protvino, near Moscow. The Cremlin+ project [1,2] aims to incorporate in this activity the best experience of European Accelerator Laboratories. The design of the optics for this SR is presented here in two declinations leading to ∼70 pm rad equilibrium horizontal emittance. The first is a 40 cells lattice, the second is the same but includes high field Short Bending magnet sources in each cell. Optics and high order multipole optimizations are performed to obtain sufficient lifetime and dynamic aperture for a conservative off-axis injection.

The European Synchrotron Radiation Facility (ESRF) operates a 6 GeV fourth generation light source, the ESRF-Extremely Brilliant Source (EBS). This storage ring is the first to implement the hybrid multibend achromat lattice (HMBA) that provides a reduction of the horizontal emittance of approximately a factor 30 with respect to the former double bend achromat structure. By combining several innovative concepts, the HMBA lattice allows the achievement of ultralow emittance while maintaining excellent lifetime and dynamic aperture performance. In this paper, beam commissioning experience and results of the new ESRF storage ring will be presented with an emphasis on the specific challenges relating to the HMBA lattice. The issues, methods, and concepts developed during the commissioning period and first months of operation are discussed.

In staggered undulators, a ferromagnetic pole structure paired to a solenoid generates a sinusoidal field. Interest of such insertion devices has been studied for application to FEL systems in the end of the previous century. However, the concept has never been used in synchrotron radiation sources due to the undesirable magnetic effect of the solenoid on electron beam parameters in storage rings. Advent of fourth-generation low emittance light sources is foreseen to change this situation. Indeed, consequent electron beam transverse size and divergence reduction for such new storage rings give promise for a beam less sensitive to the presence of a longitudinal solenoidal field. Relating to this, a staggered concept can be an adequate design choice for short-period undulators producing high-energy photon flux. Such undulators would have a low 𝐾 value a priori limiting their photon energy tunability. Considering integration of separate magnetic arrays of distinct periods in a solenoid to compose a global assembly can help suppress this possible drawback. Magnetic design and radiative performance of such an insertion device are presented.

DAΦNE, the Frascati lepton collider, has completed the preparatory phase in order to deliver luminosity to the SIDDHARTA-2 detector. DAΦNE colliding rings rely on a new interaction region, which implements the well-established Crab-Waist collision scheme, and includes a low-beta section equipped with newly designed permanent magnet quadrupoles, and vacuum components. Diagnostics tools have been improved, especially the ones used to keep under control the beam-beam interaction. The horizontal feedback in the positron ring has been potentiated in order to achieve a higher positron current. Luminosity diagnostics have been also updated so to be compatible with the new detector design. The commissioning was initially focused on recovering the optimal dynamical vacuum conditions, outlining alignment errors, and optimizing ring optics. For this reason, a detuned optics, featured by relaxed low-b condition at the interaction point and Crab-Waist Sestupoles off, has been applied. In a second stage a low-b optics has been implemented to test collisions with a preliminary setup of the experiment detector. Machine preparation and the first luminosity results are presented and discussed.

Top-up operation was recently introduced at the European Synchrotron Radiation Facility (ESRF) to provide constant beam current to the beam line users. This mode of operation involves frequent injections that can be the source of significant perturbations on the stored beam. Beam lines running experiments with a timescale longer than the injection period may be impacted by such perturbations. The ESRF storage ring injection systems and layout were not designed to allow for transparent injection, i.e., without visible perturbations on the stored beam. These perturbations are driven directly or indirectly by rapidly pulsing elements, the effect of which cannot be corrected by standard methods such as feedback loops. Major efforts were put into the development of mitigation measures at the ESRF. Depending on the source of perturbation different approaches were used. They all contribute to the achievement of transparent injections and unperturbed continuous data acquisition for the beam lines. After a review of the ESRF injection systems, these developments and the resulting reduction of the injection perturbations are described in this paper.

DAΦNE, the Italian lepton collider, is running since more than a decade thanks to a radical revision of the approach used to deal with the beam-beam interaction: the Crab-Waist Collision Scheme. In this context, the collider has recently completed a long term activity program aimed at providing an unprecedented sample of data to the KLOE-2 detector, a large experimental apparatus including a high intensity axial field strongly perturbing ring optics and beam dynamics. The KLOE-2 run has been undertaken with the twofold intent of collecting data for rare decay and flavor physics studies, and testing the effectiveness of the new collision scheme in presence of a strongly perturbing experimental apparatus. The performances of the collider are reviewed and the limiting factors discussed along with the preparatory phase activities planned to secure a new collider run to the SIDDHARTA-2 experiment.

The ESRF Extremely Brilliant Source (ESRF-EBS) lattice model is updated to include three canted beamlines. The cells are modified where necessary to include 3-Pole Wiggler (3PW), 2-Pole Wiggler (2PW) and Short Bending Magnet (SBM) sources. Several lattices are obtained for the different stages that will bring from commissioning to operation with users. A scheme for tune modification keeping key optics knobs unchanged is proposed.

The ESRF-EBS project [1] [2] foresees the replacement of the existing bending magnets beamlines with different radiation sources: short bend, 2-pole wiggler or 3-pole wiggler. After describing the reasons for these choices the required modifications to the storage ring lattice are described in details for each case. The study of the impact of lattice errors is also addressed, leading to the definition of beamlines’ alignment tolerances.

High gradient quadrupoles are necessary for different applications such as laser plasma acceleration, colliders, and diffraction limited light sources. Permanent magnet quadrupoles provide a higher field strength and compactness than conventional electro-magnets. An original design of permanent magnet based quadrupole (so-called "QUAPEVA"), composed of a Halbach ring placed in the center with a bore radius of 6 mm and surrounded by four permanent magnet cylinders capable of providing a gradient of 210 T/m, is presented. The design of the QUAPEVAs, including magnetic simulation modeling, and mechanical issues are reported. Magnetic measurements of seven systems of different lengths are presented and confirmed the theoretical expectations. The variation of the magnetic center while changing the gradient strength is +/- 10 micrometer. A triplet of three QUAPEVA magnets are used to focus a beam with large energy spread and high divergence that is generated by Laser Plasma Acceleration source for a free electron laser demonstration.

Variable high gradient permanent magnet quadrupole (QUAPEVA) F . Marteau, P. N’gotta, C. Benabderrahmane, A. Ghaith, 3 M. Valléau, A. Loulergue, J. Vétéran, M. Sebdaoui, T. André, G. Le Bec, J. Chavanne, C. Vallerand, D. Oumbarek, O. Cosson, F. Forest, P. Jivkov, J. L. Lancelot, and M.E. Couprie 3 Synchrotron-SOLEIL, Saint-Aubin, Gif-sur-Yvette 91192, FRANCE. ESRF, 71 Avenue des martyrs, Grenoble 38000, FRANCE. Université Paris-Saclay, FRANCE. LAL, Centre scientifique d’Orsay, Bt 200, BP 34, 91898, FRANCE. SigmaPhi, Rue des Frères Montgolfier, 56000 Vannes, FRANCE