The ALS-U project to upgrade the Advanced Light Source to a multi bend achromat lattice received CD-3 approval in 2022 marking the start of the construction phase for the Storage Ring. Construction of the accumulator under a prior CD-3A authorization is already well advanced. ALS-U promises to deliver diffraction limited performance in the soft x-ray range by lowering the horizontal emittance to about 70 pm rad resulting in two orders of magnitude brightness increase for soft x-rays compared to the current ALS. The design utilizes a nine bend achromat lattice, with reverse bending magnets and on-axis swap-out injection utilizing an accumulator ring. It is optimized to produce intense beams of soft x-rays, which offer spectroscopic contrast, nanometer-scale resolution, and broad temporal sensitivity. This paper presents the final design, prototype results as well as construction progress.

A system of 5,020 robotic fiber positioners was installed in 2019 on the Mayall Telescope, at Kitt Peak National Observatory. The robots automatically re-target their optical fibers every 10 - 20 minutes, each to a precision of several microns, with a reconfiguration time less than 2 minutes. Over the next five years, they will enable the newly-constructed Dark Energy Spectroscopic Instrument (DESI) to measure the spectra of 35 million galaxies and quasars. DESI will produce the largest 3D map of the universe to date and measure the expansion history of the cosmos. In addition to the 5,020 robotic positioners and optical fibers, DESI's Focal Plane System includes 6 guide cameras, 4 wavefront cameras, 123 fiducial point sources, and a metrology camera mounted at the primary mirror. The system also includes associated structural, thermal, and electrical systems. In all, it contains over 675,000 individual parts. We discuss the design, construction, quality control, and integration of all these components. We include a summary of the key requirements, the review and acceptance process, on-sky validations of requirements, and lessons learned for future multi-object, fiber-fed spectrographs.

Heavy ion facilities such as the National Superconducting Cyclotron Laboratory (NSCL) often use ECR Ion Sources (ECRIS) for the production of highly charged ions to increase the efficiency of accelerating structures. Axial bremsstrahlung emission was studied on the Superconducting Source for Ions (SuSI) at the NSCL for 18 GHz and 13 GHz operation with oxygen. The hot electron temperatures were estimated from the bremsstrahlung high energy tail and seem to depend only on magnetic minimum in the same way as was found on VENUS [1], even in the case where 18 GHz and 13 GHz frequencies were compared for similarly sized ECR zones. Additionally, the time independent x-ray power increased at a significantly larger rate when operating the source in known regions of instability such as where the magnetic minimum approaches the ECR zone [2]. The results are discussed in the context of electron losses due to magnetic confinement.

The ALS-U project is a proposed upgrade to the Advanced Light Source (ALS) at Berkeley Lab that aims to deliver diffraction limited performance and an increase of the beam brightness by two orders of magnitude for soft x-rays compared to the current ALS facility. The storage ring design utilizes a nine-bend achromat lattice, with reverse bending magnets and on-axis swap-out injection from an accumulator ring. This paper will describe the preliminary plans for the installation of a new accumulator ring (AR) in the existing tunnel, and for the removal and replacement of the existing storage ring (SR). The AR will be installed during regular maintenance shutdowns while the ALS continues to operate. The current ALS will be shutdown for a nominal twelve month darktime period, consisting of 9 months of SR removal and installation activities, followed by three months of commissioning.

The Linear Coherent Light Source II (LCLS-II) is a free electron laser facility currently in its final construction stage at Stanford Linear Accelerator Center. The project includes two variable-gap, hybrid-permanent-magnet undulator lines: A soft x-ray undulator line with 21 undulator segments optimized for a photon energy range from 0.2 keV to 1.3 keV and a hard x-ray undulator line with 32 undulator segments designed for a photon energy range from 1.0 keV to 25.0 keV. This paper focuses on the development of the hard x-ray undulator line which utilizes uniquely-developed, verticallypolarizing undulators. To fully compensate the magnetic force throughout the entire gap range these devices incorporate non-linear spring systems which permit the construction of relatively compact undulators. However, significant magnetic field repeatability challenges have been encountered during prototyping of this novel design. The paper describes some of the innovative design improvements that were implemented which lead to reaching the LCLS-II required performance. These final design solutions can also be advantageous improving the operation of any future undulator design.

The ALS-U project to upgrade the Advanced Light Source to a multi bend achromat lattice received CD-1 approval in 2018 marking the end of its conceptual design phase. The ALS-U design promises to deliver diffraction limited performance in the soft x-ray range by lowering the horizontal emittance to about 70 pm rad resulting in two orders of magnitude brightness increase for soft x-rays compared to the current ALS. The design utilizes a nine bend achromat lattice, with reverse bending magnets and on-axis swap-out injection utilizing an accumulator ring. This paper presents recent design progress of the accelerator, as well as new results of the R&D program.

Modern nuclear science ion accelerators require intense high charge state, heavy-ion beams. Electron Cyclotron Resonance (ECR) ion sources are the primary tool for generating such beams. Advances in magnet technology and an improved understanding of ECR ion source plasma physics have led to significant improvements in ECR source performance over the last several decades. The current state of the art is represented by third-generation sources operating at frequencies around 28 GHz and peak coil fields of about 7 T using NbTi conductors. Fourth-generation ECR ion source magnets designed to support ECR ion sources with an operating frequency above 40 GHz are currently under development. This paper will give an overview of the worldwide efforts underway to develop high-performance ECR sources for next-generation heavy ion accelerator facilities. ECR ION SOURCE DESIGN PARAMETERS Since the 1980s, Electron Cyclotron Resonance Ion Sources (ECRIS) have been crucial components of heavy ion science facilities [1] . The unsurpassed versatility, stability and high intensity of continuous wave (CW) high charge state ions delivered by these sources make them ideal injectors for these facilities. ECR ion sources use magnetic confinement and electron cyclotron resonance heating to produce a plasma consisting of energetic electrons (up to hundreds of keV) and relatively cold ions (a few eV). The magnetic confinement is typically achieved by a combination of a solenoidal mirror field and a sextupole field (a classical configuration is shown in Fig. 1) that creates a minimum B confinement structure where the field grows from the center of the source in every direction (longitudinally and radially). Within this confinement field a closed magnetic surface exists where the resonance cyclotron frequency of the electrons moving back and forth within the magnetic bottle equals the microwave heating frequency — allowing efficient transfer of energy from the electromagnetic field to the electrons:

The Dark Energy Spectroscopic Instrument (DESI) is under construction to determine the expansion history of the Universe using the Baryon Acoustic Oscillation technique. Over the life of the experiment DESI will measure the spectra of 35 million galaxies and quasars over 14,000 square degrees out to a redshift of 3.5. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5,000 robotic fiber positioners located at the prime focus. The fibers in turn will feed ten broad-band spectrographs covering the wavelength range from 360nm to 980 nm. Rapid and accurate targeting of the fibers is provided by precision theta-phi robotic fiber positioners. The fiber positioners are manufactured at the University of Michigan. Following assembly each positioner passes through a burn-in and verification sequence. We describe the testing of the positioners and discuss the performance achieved.

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. To achieve this goal, it is crucial to guarantee that fiber positioners work properly under the extremes of potential operating conditions, including the full range of temperatures, high speed wind disturbance etc. Thermal testing provides valuable insight into the functionality of the fiber positioners that can be used to help mitigate poor performance at extreme temperatures and wind disturbance test provide guidance to design of ventilation system. Here, we describe the thermal and wind disturbance tests for DESI fiber positioners and how the test results helped improve the robustness of the positioners.

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. We will describe the production and manufacturing processes developed for the 5000 fiber positioner robots mounted on the focal plane of the Mayall telescope.

DESI (Dark Energy Spectropic Instrument) is a Stage IV ground-based dark energy experiment that will study baryon acoustic oscillations and the growth of structure through redshift-space distortions with a wide-area galaxy and quasar redshift survey. The DESI instrument is a robotically-actuated, fiber-fed spectrograph capable of taking up to 5,000 simultaneous spectra over a wavelength range from 360 nm to 980 nm. The fibers feed ten three-arm spectrographs with resolution R= λ/Δλ between 2000 and 5500, depending on wavelength. The DESI instrument will be used to conduct a five-year survey designed to cover 14,000 deg^2. This powerful instrument will be installed at prime focus on the 4-m Mayall telescope in Kitt Peak, Arizona, along with a new optical corrector, which will provide a three-degree diameter field of view. The DESI collaboration will also deliver a spectroscopic pipeline and data management system to reduce and archive all data for eventual public use.

The design of a compact all-permanent magnet electron cyclotron resonance (ECR) ion source injector for the ReAccelerator Facility (ReA) at the Michigan State University (MSU) National Superconducting Cyclotron Laboratory (NSCL) is currently being carried out. The ECR ion source injector will complement the electron beam ion trap (EBIT) charge breeder as an off-line stable ion beam injector for the ReA linac. The objective of the ECR ion source injector is to provide continuous-wave beams of heavy ions from hydrogen to masses up to 136Xe within the ReA charge-to-mass ratio (Q/A) operational range from 0.2 to 0.5. The ECR ion source will be mounted on a high-voltage platform that can be adjusted to obtain the required 12keV/u injection energy into a room temperature radio-frequency quadrupole (RFQ) for further acceleration. The beam line consists of a 30kV tetrode extraction system, mass analyzing section, and optical matching section for injection into the existing ReA low energy beam transport (LEBT) line. The design of the ECR ion source and the associated beam line are discussed.