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Since 2020 a detailed discussion about a BESSY~II successor is ongoing at HZB and its user community in order to define the science and layout of the new facility. Still free locations close to BESSY~II have triggered a discussion about a greenfield project, but in-house upgrade solutions have also been investigated. As an additional boundary condition, BESSY~III has to meet the requirement of the Physikalische Technische Bundesanstalt (PTB) for radiation sources for metrology applications and bending magnet sources for tender X-rays. A Conceptional Design Report is in preparation. Here, we give a status report including a first parameter space, technical specifications and a first candidate for the linear lattice., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

Tracy 3 ’ was implemented by the 3rd author by pursuing a first principles approach, aka Hamiltonian dynamics for an on-line modeel to guide the ALS and LBL comissioning in the early 1990s. with its origin as a Hamiltonian based pascal online model used 90 ’ is the core of today’s accelerator tool box. These Hamiltonians have not been changed. Soft- ware design has evolved since then: C++ and in particular its standardisation C++11 and C++2xa. In this paper we out- line our strategy of modernisation of tracy: reorganisation of the beam dynamics library in cleanly designed modules, using well proven open-source libraries (GSL, armadillo) and so on. Furthermore, Python and Matlab Interfaces based on modern tools are being pursued. We report on the in- terface design, the status of modernisation. This project has been renamed to thor-scsi-lib and is available at Github. Collaboration’s welcome., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

The formula relevant for linear optics design of synchrotrons are derived systematically from first principles, i.e., an exercise in Hamiltonian dynamics. Equipped with these, the relevant use cases are then captured; for a streamlined approach. To enable professionals, i.e., software engineers, to efficiently prototype architect a CAD tool available to mechanical engineers since the mid-1960s. In other words, robust design of a modern synchrotron is an exercise in/pursuit of the art of Engineering-Science., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

The design philosophy for a robust prototype lattice design for BESSY III, i.e., that is insensitive to small parameter changes, e.g. engineering tolerances - based on a higher-order-achromat, a la: SLS, NSLS-II, MAX IV, and SLS 2 - is outlined presented. As usual, a well optimized design requires a clear understanding of the end-user requirements and close collaboration between the linear optics designer and nonlinear dynamics specialist for a systems approach., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

Digital models have been developed over a long time for preparing accelerator commissioning next to benchmarking theory predictions to machine measurements. These digital models are nowadays being realized as digital shadows or digital twins. Accelerator commissioning requires periodic setup and review of the machine status. Furthermore, different measurements are only practical by comparison to the machine model (e.g. beam based alignment). In this paper we describe the architecture chosen for our models, describe the framework Bluesky for measurement orchestration and report on our experience exemplifying on dynamic aperture scans. Furthermore we describe our plans to extend the models applied to BESSY~II and MLS to the currently planned machines BESSY~III and MLS~II., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

HZB operates and develops two synchrotron radiation sources at Berlin Adlershof. The larger one, BESSY II with an energy of 1.7 GeV and 240 m circumference is optimized for soft-X rays and in operation since 1999. The smaller one is the MLS (Metrology Light Source), owned by the Physikalische Technische Bundesanstalt (PTB) - Germany’s National Metrology Institute. It is designed to fulfill the special metrology needs of the PTB with an energy of 0.6 GeV and 48 m circumference, covering the spectral range from THz and IR to EUV/VUV. In 2020 a discussion process has been started to define the requirements for successors of BESSY II and MLS and to study the possibilities integrate them into a new photon science facility in Berlin Adlershof. Here, we give a status report and present a first envisaged parameter space to both machines (see also MOPAB262, MOPAB220, MOPAB048, MOPAB242)., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

The ALS Upgrade to a diffraction-limited soft x-ray storage ring calls for ultralow emittance in a very limited circumference. In this paper we report on progress with a lattice based on a 7BA with distributed chromatic correction. This lattice relies heavily on longitudinal gradient bends and reverse bending in order to suppress the emittance, so that, despite having only seven bends, ultralow emittance can be achieved in addition to large dynamic aperture and momentum acceptance. An initial alternate 7BA lattice has been revised to relax magnet requirements as well as further increase off-energy performance and resilience to machine imperfections. We now demonstrate ±2.5 mm dynamic aperture including errors and calculate the effect of IBS to show that this lattice achieves 6 hours Touschek lifetime (at 500 mA, including errors) and a brightness of roughly 3x10²¹ ph/s/mm²/mrad²/0.1%BW at 1 keV., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

A Lattice for a 500 m circ. Tunnel, based on First Principles Best Practices is presented. Background: MAX-IV has made a "quantum leap" towards a Diffraction Limited Storage Ring (DLSR) by an Engineering-Science, i.e., Systems, Approach; leading to a Paradigm Shift(s): e.g. the Magnet Reference Radius is a Key Parameter, a Design Choice, that must be considered at an early stage for Robust Design. In addition, the pursuit of Systematic Benchmarks, MAX-I -> MAX-IV, has enabled the pursuit of Disruptive Technologies with Predictable Results. For example: Combined-Function Magnets (built-to-print) enabling an "IKEA Approach" (innovative, prompted by low-budget) like the use of Concrete Girders, Vacuum Requirements mitigated by NEG Coating, and Solid State Modulators providing a Reliable Injector by a Full-Energy Linac. Since "The Experiment" now has been done, Permanent Magnets, well understood for high-end Insertion Devices, provides another opportunity/step for a Next Generation. Besides, the Electricity Bill for Conventional Magnets is a significant part of the Operations Cost., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

We pursue Robust Design of a Ring-Based Synchrotron Light Source as a System. In particular, the Design Phi-losophy is based on: ’ To Control the Nonlinear Dynamics: Control the Linear Optics. In particular, by: ’ Optimal Control of Natural Chromaticity. ’ ’-I Transformer’ between Chromatic Sextupoles for Unit Cell. ’ Higher-Order-Achromat for Super Period. In addition, by pushing the Requirements for Robust Efficient Injection ’Upstream’, i.e., by considering On-Axis Injection, and by utilizing Reverse Bends (to trans-cend the reductionist Theoretical Minimum Emittance Cell), either: ’ the Natural Emittance can be reduced further, ’ or the Touschek Lifetime can be improved. Bottom line, a Design Choice., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

MAX-IV has introduced a paradigm shift in the design philosophy for the "Engineering-Science" in the quest for a diffraction limited Synchrotron Light Source. Similarly, SLS-2 has introduced a systematic method for controlling the Linear Optics beyond some 20 years of TME inspired paper designs; by introducing Reverse Bends to disentangle dispersion and focusing, which enables Longitudinal Gradient Bends to efficiently reduce the emittance. Similarly, we outline a systematic approach for how to control the Nonlinear Dynamics for these systems, by a method that was pioneered for the conceptual design of the Swiss Light Source in the mid-1990s; subsequently benchmarked and validated by the commissioning., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

Generalized MBA (Multi-Bend-Achromat) Chasman-Green type lattices, with a low-dispersion mid-straight, have been studied and refined by pursuing a generalized Higher Order Achromat to control the non-linear dynamics to obtain a robust design. New candidate lattice have been produced aiming for a horizontal emittance of 150 pm×rad for off-axis injection and 75 pm×rad for on-axis, the latter making use of reverse bends. The results of these studies and evaluations have been summarized in this paper., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

A fast new linear lattice characterization / correction method based on turn-by-turn (TbT) beam position monitor (BPM) data in storage rings has been recently developed and experimentally demonstrated at NSLS-II. This method performs least-square fitting iteratively on the 4 frequency components extracted from TbT data and dispersion functions. The fitting parameters include the errors for normal/skew quadrupole strength and 4 types of BPM errors (gain, roll, and deformation). The computation of the Jacobian matrix for this system is very fast as it utilizes analytical expressions derived from the resonance driving terms (RDT), from which the method name DTBLOC (Driving-Terms-Based Linear Optics Characterization/Correction) originates. At NSLS-II, a lattice corrected with DTBLOC was estimated to have beta-beating of, Proceedings of the North American Particle Accelerator Conf., NAPAC2016, Chicago, IL, USA

The injector for the National Synchrotron Light Source II storage ring consists of a 3 GeV booster synchrotron and a 200 MeV S-band linac. The linac was designed to produce either a single bunch with a charge of 0.5 nC of electrons or a train of bunches up to 300 ns long containing a total charge of 15 nC. The booster was designed to accelerate up to 15 nC each cycle. Linac commissioning was completed in April 2012. Booster commissioning was started in November 2013 and completed in March 2014. All of the significant design goals were satisfied including beam emittance, energy spread, and transport efficiency. While the maximum booster charge accelerated was only 10 nC this has proven to be more than sufficient for storage ring commissioning. The injector has operated reliably during storage ring operation since then. Results will be presented showing measurements of injector operating parameters achieved during commissioning and initial operation. Operating experience and reliability during the first year of NSLS-II operation will be discussed., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

In this paper we describe our experience with commissioning of the first turns in the NSLS-II storage ring. We discuss the problems that we encountered and show how applying a dedicated first turns commissioning software allowed us to diagnose and resolve these problems., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

The National Synchrotron Light Source II (NSLS-II) is a state of the art 3 GeV third generation light source at Brookhaven National Laboratory. In the spring 2014, the storage ring was commissioning up to 50 mA without insertion device. In the fall, the project beamlines, includes seven insertion devices on six ID ports were commissioned within two and a half months. These beamlines consist of IXS, HXN, CSX-1, CSX-2, CHX, SRX, and XPD-1, from the radiation sources elliptically polarizing undulator (EPU), damping wiggler (DW) and in vacuum undulator (IVU) to cover the VUV through the very hard x-ray range. In this paper, a number of commissioning and operation experiences are discussed here, such as injection, lifetime, ID residual field and compensation, source point stability, beam alignment and tools for control, monitor and beam protection., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA