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Advanced Photon Source

The Advanced Photon Source (APS) is a synchrotron radiation light source facility located at Argonne National Laboratory in Lemont, Illinois, operated by the U.S. Department of Energy's Office of Science, that produces the world's brightest beams of X-rays for scientific research across disciplines including materials science, biology, chemistry, and physics.^[1] It consists of a 6 GeV electron storage ring with a circumference of approximately 1,104 meters and a design current of 200 mA, designed to generate high-brilliance X-rays using bending magnets and insertion devices, and serving as one of five major X-ray light sources in the United States.^[2] Construction began with groundbreaking on June 4, 1990, and the facility achieved first light on March 26, 1995, marking it as the first high-energy third-generation synchrotron in the U.S., with full research operations commencing in the fall of 1996.^[3] Historically, the APS has supported approximately 5,500 scientists annually from universities, industry, and national laboratories, who conduct over 6,000 experiments each year at its 72 beamlines, with access provided free for non-proprietary research and on a cost-recovery basis for proprietary work; post-upgrade operations are resuming in 2025.^[4] Over its history, the facility has enabled more than 37,000 peer-reviewed publications and contributed to three Nobel Prizes in Chemistry—in 2009 for ribosome structure, 2012 for G-protein-coupled receptors, and 2024 for protein design—while advancing discoveries in energy storage, quantum materials, microelectronics, and public health.^[3] The APS completed a major upgrade project in 2025, replacing its original storage ring with a new multibend achromat lattice operating at 6 GeV and 200 mA, with first electrons achieved in April 2024 at a total project cost of $815 million, delivering X-ray beams up to 500 times brighter than before and establishing it as the first fourth-generation synchrotron light source in the U.S.^[5] Post-upgrade, the APS achieved a world-record horizontal emittance of 33 pm·rad in 2025, reducing electron beam emittance to unprecedented levels for enhanced coherence and flux, enabling time-resolved studies of ultrafast processes and atomic-scale imaging that were previously unattainable.^[6] With over 450 staff members supporting operations, the upgraded APS continues to drive transformative science, including breakthroughs in sustainable energy technologies and biomedical applications.^[4]

History

Development and construction

The Advanced Photon Source (APS) originated in the early 1980s as part of a U.S. Department of Energy (DOE) initiative to develop third-generation synchrotron radiation sources capable of producing high-brilliance X-rays for advanced scientific research. A DOE-sponsored planning study in March 1984 recommended the construction of a dedicated high-brilliance X-ray facility, leading to the selection of Argonne National Laboratory as the host site in Lemont, Illinois. Conceptual design efforts followed, with Argonne publishing a 6-GeV Synchrotron X-ray Source report in February 1986 and upgrading to a 7-GeV Advanced Photon Source Conceptual Design Report in April 1987, emphasizing a storage ring optimized for hard X-ray production.^[7]^[8] Key milestones advanced rapidly in the late 1980s. In May 1988, the DOE approved the project start, authorizing the transition from conceptual to full development. The first construction funds were released on October 1, 1989, followed by groundbreaking on June 4, 1990, which marked the beginning of site preparation and building on Argonne's 80-acre campus. Funding came primarily from the DOE Office of Science, with a total construction cost of approximately $467 million, supporting the design of a 7-GeV electron storage ring with a circumference of 1,104 meters to generate intense hard X-ray beams.^[7]^[9] Construction faced significant logistical challenges, including the integration of a linear accelerator, booster synchrotron, and the main storage ring within the constrained site, requiring over 2 million man-hours from 72 subcontractors. An aggressive safety program ensured no serious injuries, achieving an accident rate one-quarter of the U.S. industrial average, while managing extensive materials such as 54,600 cubic yards of concrete and 5,800 tons of structural steel for shielding and support structures. By October 1993, linac commissioning began with a 50-MeV electron beam, paving the way for storage ring integration, and the project completed ahead of schedule with first light achieved on March 26, 1995.^[9]^[7]

Commissioning and early operations

The commissioning of the Advanced Photon Source (APS) began with the successful storage of the first 4.5 GeV electron beam in the storage ring on March 25, 1995, followed by the detection of the first bending magnet radiation on March 26, 1995. This milestone marked the initial activation of the synchrotron light source at Argonne National Laboratory. Shortly thereafter, on August 9, 1995, the first undulator X-ray beam was produced, exceeding specifications for brightness and spectral performance.^[9] By early 1996, the facility achieved key operational parameters, including the first 100 mA stored electron beam on January 12 and the operation of an undulator with this current on January 26. In July 1996, the first 7 GeV positron beam was stored, reaching 100 mA the following day, aligning with the design goals for high-energy, high-current operation to generate intense synchrotron radiation. The official dedication ceremony occurred on May 1, 1996, highlighting the facility's readiness for scientific use.^[9] Initial beamline installations focused on insertion devices, including undulators and wigglers, to produce tunable X-ray beams from synchrotron radiation generated by the accelerated electrons (or positrons).^[10] These devices were installed in the 35 straight sections of the 40-sector storage ring, enabling the extraction and utilization of high-brilliance X-rays for experiments. The user program launched in fall 1995 with the first research experiments, rapidly expanding as beamlines became operational.^[11] By 2000, the APS served over 2,000 unique users annually, supporting a diverse range of studies.^[12] Throughout its early years into the mid-2000s, the APS maintained high operational reliability, averaging 95% availability for scheduled beam time, which supported consistent user access despite ongoing expansions and optimizations.^[13] This uptime was achieved through robust accelerator controls and feedback systems, ensuring stable beam parameters essential for precise X-ray experiments.^[14]

Facility design

Accelerator complex

The Advanced Photon Source (APS) accelerator complex consists of a three-stage system designed to generate high-energy electron beams for synchrotron radiation production. The initial stage is a 450 MeV linear accelerator (linac) that provides electron injection into the subsequent rings.^[15] This is followed by a 6 GeV booster synchrotron, which ramps up the beam energy over approximately one-third of a second at a 2 Hz repetition rate.^[16] The final stage is the main storage ring, a 1,104-meter circumference circular accelerator that maintains the beam at nominal parameters for extended periods.^[17] Key components of the complex include 40 straight sections in the storage ring, which accommodate insertion devices such as undulators and wigglers to enhance radiation output.^[2] The ring features hundreds of dipole magnets for beam bending, distributed across its 40 sectors, along with quadrupole and sextupole magnets for focusing and correction.^[18] Extensive vacuum systems maintain an ultra-high vacuum of approximately 10^{-10} Torr to minimize beam scattering and ensure stability.^[19] The complex now operates with electron beams following the 2023-2024 upgrade, which eliminated the need for positron production due to the adoption of swap-out injection.^[18] The infrastructure encompasses a 200,000 square foot experiment hall that houses 72 beamlines, enabling diverse experimental setups around the storage ring. Utilities include cryogenic cooling systems for superconducting insertion devices and magnets, ensuring low-temperature operation for high-performance components.^[20] Radiation shielding, consisting of concrete walls and beamline hutches, along with safety interlocks and monitoring, protects personnel and the environment from high-energy radiation. The facility is situated on the 1,500-acre Argonne National Laboratory campus, approximately 25 miles southwest of Chicago, Illinois, integrating seamlessly with broader laboratory operations.^[8] The accelerator operates at a nominal beam energy of 6 GeV with a stored current of 200 mA, optimized for generating intense synchrotron radiation across a wide spectral range.^[21]

Storage ring and beamlines

The storage ring of the Advanced Photon Source (APS) is a fourth-generation synchrotron light source employing a multibend achromat lattice with 40 sectors, each alternating a straight section and multiple dipole bends to maintain the electron beam orbit.^[22] The ring has a circumference of 1,104 meters and operates with 6 GeV electrons stored at 200 mA, enabling the production of synchrotron radiation through bending magnets and insertion devices.^[2] Electrons are injected from the booster synchrotron into the ring using swap-out injection, where they circulate for hours while emitting X-rays. This design optimizes low emittance for high-brightness beams, achieving a horizontal emittance of approximately 33 pm·rad.^[17]^[6] Insertion devices are installed in 35 of the 40 straight sections, each 4.8 meters long, to generate intense, tunable X-ray beams. The APS features 29 undulators, primarily hybrid permanent magnet types with periods of 2.8 to 3.3 cm, and 11 wigglers, including superconducting and multipole variants, which collectively produce photons ranging from infrared wavelengths to hard X-rays exceeding 100 keV.^[23] Undulators deliver coherent, high-brightness radiation for applications requiring fine spectral resolution, while wigglers provide higher flux for broader energy spectra and penetration studies. The post-upgrade peak brightness reaches up to $5 \times 10^{20} photons/s/mm²/mrad²/(0.1% BW) at a 1 Å wavelength, establishing the APS as the world's leading source for hard X-ray research.^[24] The beamline network branches from the storage ring across 35 sectors in the experimental hall, with each sector supporting 1 to 3 beamlines for a total of 72 operational stations. X-rays from insertion devices and bending magnets are transported via front ends equipped with high-heat-load absorbers, filters, and shutters to protect downstream optics and select specific energies while managing power loads up to several kilowatts.^[25] These front ends include diagnostic components like beam position monitors to ensure alignment. To maintain beam quality, sophisticated feedback systems correct the electron orbit in real time, achieving position stability at the micron level (typically 1–2 μm rms over 1–100 Hz frequencies), which is critical for high-resolution experiments.^[26]

Operations

Beam production and synchrotron radiation

The electron beam for the Advanced Photon Source is produced in a linear accelerator (linac) that accelerates bunches to an energy of 450 MeV before injection into the positron accumulator ring (PAR). From the PAR, the beam is transferred to the booster synchrotron, where it is ramped up to 6 GeV over approximately 500 ms, with cycles adjusted for the upgraded system; full filling to operational current typically occurs over about 15 minutes without continuous injection.^[27] Swap-out injection from the booster maintains a stable circulating current of 200 mA in the storage ring by replacing spent electron bunches with fresh ones, enabling uninterrupted experiments while preserving the low emittance required for fourth-generation performance.^[28]^[29] In the 1.1 km circumference storage ring, the relativistic electrons follow a closed orbit defined by a hybrid multibend achromat (HMBA) lattice with 280 dipole magnets, compelling the charged particles to accelerate perpendicular to their velocity and emit synchrotron radiation forward in a narrow cone tangent to the orbit. This radiation arises from the classical electromagnetic fields of the accelerated charges, producing a continuous spectrum with intensity peaking near the critical energy E_c, given by

E_c = \frac{3}{2} \frac{\hbar c \gamma^3}{\rho},

where γ is the Lorentz factor (γ ≈ 11,700 for 6 GeV electrons), ħ is the reduced Planck's constant, and c is the speed of light; for the APS dipoles, this yields E_c ≈ 19.5 keV, with significant photon flux extending to higher energies, maintained similar to pre-upgrade via adjusted bending fields and radii.^[30]^[31] The synchrotron radiation from bending magnets offers a broad, untunable spectrum suitable for white-beam applications, extending up to several times the critical energy with most power below 30 keV. In contrast, insertion devices such as undulators enhance brightness by arranging periodic magnetic fields to induce coherent oscillations in the electron trajectory, resulting in sharp spectral peaks tunable by adjusting the device gap and thus the undulator parameter K = (e B_0 λ_u)/(2 π m c^2), where B_0 is the peak magnetic field and λ_u is the period length. The on-axis brightness at these peaks scales with K^2 and the number of periods N_u, enabling photon energies from soft X-rays to beyond 30 keV depending on the specific undulator configuration, with the upgrade delivering up to 500 times higher brightness.^[3] The circulating beam experiences energy loss per turn due to synchrotron radiation, on the order of hundreds of keV, which is restored by a superconducting RF system operating at 352 MHz with a total accelerating voltage of approximately 6.4 MV across multiple cavities to maintain beam stability and compensate for damping. Beam lifetime in the ring is approximately 4-6 hours, dominated by Touschek scattering—intra-beam Coulomb collisions that eject particles from the bunch due to the high charge density—and mitigated by radiation damping, which restores transverse emittance but contributes to overall loss; residual gas scattering provides a minor additional limit under ultra-high vacuum conditions.^[31]

User access and experiments

The Advanced Photon Source operates a robust user program that enables researchers worldwide to access its facilities through a competitive, peer-reviewed proposal process managed via the Universal Proposal System (UPS), a collaborative platform developed by multiple national laboratories.^[32] Proposals are reviewed by Beam Time Allocation Committees, with successful applicants allocated beam time based on scientific merit and facility availability. In a typical year, the APS serves approximately 5,500 scientists, who conduct over 6,000 experiments utilizing around 5,000 scheduled beam hours at its 72 beamlines. This program supports a diverse global community, including efforts to engage underrepresented groups in science through targeted outreach and inclusive policies.^[4]^[33] Experiments at the APS are conducted during three annual run cycles, each lasting approximately three to four months, with intervening shutdown periods for maintenance and upgrades.^[34] The facility achieves a minimum uptime of 97% for synchrotron radiation and X-ray availability, defined as the hours when beam shutters are open and stored current exceeds 50 mA, divided by scheduled delivery hours.^[35] Since the 2024 upgrade, operations have utilized swap-out injection mode to maintain stable beam flux and low emittance by periodically replacing electron bunches in the storage ring without interrupting user experiments.^[29] Safety is paramount in user operations, with protocols enforced through the Experiment Safety Assessment Form (ESAF), which must be submitted at least 14 days in advance for onsite experiments to identify hazards such as radioactive materials, cryogens, high voltage, and lasers.^[36] All personnel accessing the experiment hall require dosimetry for radiation monitoring and must complete General Employee Radiation Training (GERT), along with sector-specific orientations covering access controls via photo badges and cardkey systems.^[37] Additional training is mandatory for handling hazardous materials, ensuring compliance with ALARA (As Low As Reasonably Achievable) principles to minimize exposure.^[38] Support facilities enhance experiment efficiency, including on-site laboratories through the Experimental Support Services (ESS) for sample preparation tasks like wet chemistry, purification, and solid processing.^[39] Remote access options, expanded significantly post-2020 to accommodate virtual participation amid global travel restrictions, allow users to control beamlines via NoMachine cloud servers and retrieve data through Globus transfer services. Data management and beamline operations are facilitated by the Experimental Physics and Industrial Control System (EPICS), providing real-time monitoring and automation for experiment execution. As of October 2025, 51 beamlines are accepting users, enabling advanced studies leveraging the upgraded source's enhanced coherence and flux.^[40]^[33]

Scientific impact

Applications in research

The Advanced Photon Source (APS) supports a suite of core X-ray techniques that enable atomic- and nanoscale investigations across scientific disciplines. These include X-ray diffraction for determining crystalline structures, small- and wide-angle X-ray scattering for probing nanoscale morphologies and dynamics, X-ray absorption spectroscopy (such as XANES and EXAFS) for analyzing electronic and local atomic environments, and X-ray imaging modalities like microtomography, which achieves spatial resolutions down to 1 μm for three-dimensional visualization of internal structures.^[41]^[42] These techniques leverage the APS's high-brilliance synchrotron radiation to provide non-destructive, high-throughput data collection, often in operando conditions to capture real-time processes.^[43] In materials science, APS beamlines facilitate detailed studies of energy storage and advanced manufacturing processes. For instance, researchers have used time-resolved X-ray tomography and spectroscopy to observe lithium-ion dynamics within battery electrodes during charge-discharge cycles, revealing degradation mechanisms that inform the design of longer-lasting lithium-ion batteries.^[44] Similarly, in additive manufacturing, high-energy X-ray diffraction and imaging have elucidated microstructures in 3D-printed alloys, such as how magnetic fields influence grain orientation in stainless steels to enhance mechanical properties.^[45] These applications underscore the APS's role in optimizing material performance for sustainable technologies. Biological sciences benefit from APS capabilities in structural biology and imaging, particularly for drug discovery and neuroscience. Protein crystallography at dedicated beamlines like those in Sector 19 has enabled the determination of thousands of macromolecular structures, aiding the rational design of therapeutics by visualizing protein-ligand interactions at atomic resolution.^[46] In neuroscience, phase-contrast X-ray imaging supports brain mapping by providing high-contrast, non-destructive 3D reconstructions of neural tissues, complementing chemical analysis of trace elements to study connectivity and pathology.^[47] In environmental science and chemistry, the APS excels at investigating reaction mechanisms and contaminant behaviors under realistic conditions. Operando X-ray absorption spectroscopy has been applied to monitor catalyst structures during reactions, such as gold nanoparticles oxidizing carbon monoxide, providing insights into active sites for emission control technologies.^[48] For pollutant studies, techniques like HERFD-XANES enable precise speciation of elements like arsenic in mine wastes, assessing toxicity and mobility to guide remediation strategies.^[49] Industrial applications leverage APS X-rays for quality assurance and failure diagnostics in high-tech sectors. In electronics, synchrotron-based imaging and spectroscopy support failure analysis of power devices, identifying defects in wide-bandgap semiconductors like GaN to improve reliability in extreme environments.^[50] For additive manufacturing, real-time tomography ensures quality control by detecting voids and microstructural flaws in printed components, accelerating certification for aerospace and automotive uses.^[51] During the COVID-19 pandemic (2020-2021), the APS played a pivotal role in structural biology efforts, with 224 crystal structures of SARS-CoV-2 proteins—including the spike protein—determined between January 2020 and September 2021 to guide antibody design and mRNA vaccine development, such as stabilizing prefusion conformations for Moderna and Pfizer vaccines.^[52] The facility's upgrade, now operational, boosts X-ray brightness by up to 500 times, enhancing resolution and speed for such time-sensitive interdisciplinary research.^[53]

Notable discoveries and awards

The Advanced Photon Source (APS) has contributed to three Nobel Prizes in Chemistry, recognizing groundbreaking structural biology research enabled by its high-brilliance X-ray beams. In 2009, the prize was awarded to Venkatraman Ramakrishnan, Thomas A. Steitz, and Ada E. Yonath for studies on the structure and function of the ribosome; Ramakrishnan and Steitz utilized APS beamlines to obtain atomic-level resolution images essential for understanding protein synthesis.^[54] In 2012, Brian K. Kobilka and Robert J. Lefkowitz received the award for research on G protein-coupled receptors (GPCRs), with Kobilka employing APS X-rays to determine the first high-resolution structure of an activated GPCR, advancing drug design for this critical class of signaling proteins.^[55] Most recently, in 2024, David Baker, Demis Hassabis, and John M. Jumper were honored for computational protein design and structure prediction; Baker's team leveraged APS facilities to validate novel protein structures through X-ray crystallography, confirming designs that enable new therapeutic applications.^[56] Key discoveries at the APS span multiple decades and fields. In the 1990s, shortly after operations began in 1995, researchers achieved pioneering atomic-resolution protein structures, such as those of enzymes and viral proteins, which revolutionized structural biology by revealing precise molecular interactions previously unattainable with conventional sources.^[57] During the 2000s, APS studies uncovered nanoscale degradation mechanisms in lithium-ion batteries, identifying lithium dendrite formation and electrode cracking that limit battery lifespan, informing improvements in energy storage for electric vehicles and renewables.^[58] In the 2010s, investigations into quantum materials revealed phase transitions in superconductors and topological insulators, such as pressure-induced changes in iron-based compounds, providing insights into exotic states of matter for next-generation electronics.^[59] The APS's scientific impact is evidenced by its prolific output, with users generating over 2,000 peer-reviewed publications annually that cite facility contributions, spanning biology, materials science, and energy research.^[8] These efforts have directly supported three Nobel Prizes and influenced broader advancements in physics and chemistry through structural and dynamical studies. In the 2020s, APS research has yielded highlights in energy and health sciences, including operando X-ray analyses that enhanced perovskite solar cell efficiency by elucidating ion migration and defect formation, contributing to single-junction cell performance up to 26% conversion efficiency for scalable photovoltaics.^[60] Additionally, structural determinations of amyloid-beta fragments and oligomers have advanced understanding of Alzheimer's disease pathology, revealing aggregation pathways that guide targeted therapies to disrupt plaque formation.^[61] APS-enabled discoveries have driven substantial economic value, particularly in pharmaceuticals, where X-ray structures facilitated development of blockbuster drugs like Kaletra (lopinavir/ritonavir), an HIV protease inhibitor approved in 2000 that generated billions in global sales and saved countless lives by halting AIDS progression.^[62] Similar contributions in semiconductors, through atomic-scale imaging of nanomaterials, have optimized transistor designs and supported the multi-trillion-dollar electronics industry.

Upgrade project

Project objectives

The APS Upgrade (APS-U) project was motivated by the limitations of the original storage ring, which, despite its advancements since commissioning in 1995, struggled to deliver sufficient X-ray brightness and coherence for emerging fields like nanoscience, ultrafast dynamics, and in situ materials studies under extreme conditions. With global competitors such as the European Synchrotron Radiation Facility (ESRF) and SPring-8 pursuing major upgrades to low-emittance lattices, the project aimed to sustain U.S. leadership in hard X-ray science by leveraging the existing infrastructure to cost-effectively enhance capabilities for Department of Energy missions in energy, environment, biology, and national security.^[63]^[22] Key technical goals included achieving a 100- to 1000-fold increase in X-ray brightness for multi-keV photons and up to three orders of magnitude higher coherent flux, enabling diffraction-limited imaging at nanoscale resolutions and time-resolved experiments with picosecond pulses. The project targeted a dramatic reduction in horizontal emittance from the original 3 nm·rad to ≤42 pm·rad at 200 mA operating current, alongside improvements in beam stability and single-bunch brightness by factors of up to 25 times at select energies. These enhancements would support advanced techniques such as X-ray photon correlation spectroscopy (XPCS), ptychography, and high-energy tomography, prioritizing conceptual breakthroughs over exhaustive metrics.^[22]^[64]^[63] To realize these goals, the design incorporated a 7-bend multi-bend achromat (MBA) lattice to minimize emittance, featuring 35 insertion-device straight sections (with three dedicated to RF cavities) and replacing outdated components with advanced magnet systems, including permanent magnets for quadrupoles and dipoles, and superconducting undulators for higher flux. Beamline development focused on nine new high-performance beamlines optimized for ultimate coherence—such as long-distance setups for imaging and spectroscopy—and upgrades to 15 existing ones, culminating in a total of 72 beamlines to maximize scientific throughput.^[22]^[65] The project's scope was funded by $815 million from the U.S. Department of Energy, spanning the 2010s to 2020s, with Critical Decision-3 (start of construction) approved in July 2019 following the final design review. This investment emphasized safety, efficiency, and integration with the existing accelerator complex while avoiding full reconstruction.^[66]^[22]

Implementation and timeline

The APS Upgrade (APS-U) project unfolded across distinct phases, commencing with conceptual design from 2009 to 2014, during which the U.S. Department of Energy (DOE) approved the mission need in April 2010 and the Conceptual Design Report was finalized in 2011.^[63]^[12] This phase established the multi-bend achromat lattice as the core architectural innovation for enhancing beam brightness. Detailed engineering followed from 2015 to 2020, incorporating DOE Critical Decision 1 approval in May 2016 for design refinement and performance baseline, culminating in the Final Design Report in May 2019 and Critical Decision 3 approval in July 2019 to initiate procurement.^[67]^[68] Procurement and assembly spanned 2021 to 2023, focusing on fabricating over 1,300 magnets and integrating vacuum chambers into 200 pre-assembled modules offsite before tunnel delivery.^[69] Key milestones marked steady progress despite external pressures. The original storage ring shut down on April 17, 2023, initiating a one-year removal and installation period that minimized broader facility disruption by prioritizing accelerator components.^[70] New ring installation proceeded through 2024, with all modules aligned by March 2024; the first stored electron beam circulated on April 20, 2024, validating initial accelerator functionality.^[71] Beamline commissioning began immediately thereafter in a phased approach, achieving DOE Critical Decision 4 project closeout approval in September 2025 following verification of key performance parameters.^[72] The project faced significant challenges, including supply chain delays exacerbated by the COVID-19 pandemic, which affected component delivery and extended prototyping timelines.^[73] Magnet fabrication demanded sub-micron precision for the multi-bend achromat quadrupoles to maintain beam stability, while vacuum system integration required innovative thin-walled chambers compatible with the denser lattice—issues addressed through rigorous measurement protocols and vendor partnerships.^[74]^[69] These were resolved via collaborations with international vendors for specialized components like MBA magnets, ensuring compliance with exacting tolerances.^[75] Over 1,000 personnel contributed across Argonne National Laboratory staff, contractors, and external experts, with vendor contracts handling the bulk of MBA magnet production and module assembly to leverage specialized manufacturing capabilities.^[76] Transition strategies emphasized hybrid operations, allowing select beamlines to resume limited activities during installation to minimize scientific downtime; initial user experiments restarted in summer 2024, with full general user operations expanding by September 2024.^[77]^[78]

Post-upgrade performance

Following the successful completion of the APS Upgrade Project, the facility achieved key performance parameters surpassing some design goals, including a horizontal emittance of 33 pm·rad (as of May 2025, surpassing the design of 42 pm·rad) and a vertical emittance of approximately 32 pm·rad at nominal operating currents.^[6]^[47] This low-emittance electron beam enables X-ray brightness on the order of 10^{21} photons/s/mm²/mrad²/0.1% bandwidth, representing a 500-fold improvement over the pre-upgrade configuration and supporting advanced coherent scattering techniques.^[6]^[22] Beam stability has been maintained at levels of 4 μm vertically and 15 μm horizontally in brightness mode, ensuring reliable delivery for high-resolution experiments.^[79] Early operations commenced with the first user run in January 2025, marking the return to scientific activities after the upgrade shutdown.^[80] By October 2025, 51 of the 72 beamlines were accepting general users, with a total of 4,896 beam hours delivered during the fiscal year, slightly below the target of 5,000 hours to accommodate additional commissioning needs.^[33] These initial runs have demonstrated robust multi-bunch operation at currents up to 200 mA, with swap-out injection maintaining beam quality throughout extended periods.^[81] Performance highlights from early experiments underscore the upgraded APS's enhanced capabilities, particularly in coherence for atomic-scale imaging applications such as ptychography and X-ray photon correlation spectroscopy (XPCS).^[47] Initial results at feature beamlines like POLAR (4-ID) and CSSI (9-ID) have shown up to a 10-fold increase in data acquisition rates compared to pre-upgrade baselines, enabling real-time analysis of dynamic processes in materials and biological samples.^[82] Commissioning efforts encountered minor delays due to beam stability tuning and insertion device integration in early 2025, but these were resolved by August 2025 through refinements to the fast orbit feedback systems and bunch lengthening implementations.^[83] The APS Strategic Plan 2025-2029 further outlines optimizations, including superconducting undulator deployments and AI-assisted data management, to maximize throughput and coherence utilization across the facility.^[84] Looking ahead, the upgraded APS is projected to reach full operational capacity with all 72 beamlines by mid-2026, supporting expanded access for diverse scientific communities.^[33] As a leading fourth-generation light source, it holds potential for further enhancements, such as advanced timing modes and hybrid bunch schemes, while user numbers are expected to grow beyond 6,000 annually through initiatives like eBERlight for biological and environmental research.^[47]

References

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Overview | Advanced Photon Source - Argonne National Laboratory
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[PDF] THE ADVANCED PHOTON SOURCE LIST OF PARAMETERS
The Advanced Photon Source linac system consists of a 200-MeV, 2856-MHz, S-band electron ... Energy spread, rms, at 7 GeV. 1.0 × 10. -3. Energy gain per turn.
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[4]
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Oct 10, 2025 · Welcome to the Advanced Photon Source (APS) at Argonne National Laboratory. The APS is the brightest synchrotron X-ray light source in the ...
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[PDF] Accelerator Upgrade Document Number : APSU-2.01
current, means that the Upgrade must inject about forty times more electrons into the storage ... Electron energy (GeV). 7. 6. 6. Beam Current (mA). 100. 200. 200.
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Below is a merged summary of the Advanced Photon Source (APS) development, construction, funding, and DOE involvement from the 1980s-1990s, consolidating all information from the provided segments. To retain maximum detail, I’ve organized key information into a dense, tabular format where appropriate, followed by a narrative summary for additional context. This ensures all data points are captured efficiently and comprehensively.
[8]
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[9]
[PDF] Advanced Photon Source - Argonne National Laboratory
When the Department of Energy received Congressional funding to construct the Advanced. Photon Source, the proposed date for operation was summer of 1996.
[10]
[PDF] ANL-92/20 - Advanced Photon Source
Dec 30, 1992 · Several IDs have been identified as standard x-ray sources for Tye A Sectors. These include two planar undulators and two planar wigglers.2 ...
[11]
75 Years of Discovery | Argonne National Laboratory
The Advanced Photon Source (APS) saw first light in 1995 and began research experiments in 1996. The APS generates ultrabright X-rays that enable a host of ...
[12]
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The Project is an upgrade of the existing third-generation APS light source which will enable APS to provide an unprecedented combination of high-energy, high- ...
[13]
[PDF] Magnet Power Supply Reliability at the Advanced Photon Source
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[14]
APS storage ring commissioning and early operational experience
Jul 1, 1995 · Real-time closed orbit feedback is employed to achieve the required stability and is discussed elsewhere in these proceedings. Installation of ...<|separator|>
[15]
https://ieeexplore.ieee.org/document/308840
[16]
[PDF] The Advanced Photon Source: A Status Report* - OSTI
Aview of the Advanced Photon Source construction site in October. 1991. The foundation and structural steel beams for the injection complex (linac and ...
[17]
APS Storage Ring Parameters
Aug 27, 2024 · Circumference, C · 1103.609 ; Revolution frequency, f · 271.647 ; Revolution time, T · 3.681 ; Harmonic number, h · 1296 ; Typical RF voltage, V · 4.5 ...
[18]
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[19]
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May 30, 2024 · We are continually refining the schedule for bringing up all 71 beamlines ... The Advanced Photon Source is an Office of Science User Facility ...
[20]
Accelerator Systems - Argonne National Laboratory
The APS accelerator complex consists of the 7-GeV, 1.1-km storage ring operating with a 100-mA electron beam; the full-energy booster synchrotron; the 400-MeV ...
[21]
[PDF] Advanced Photon Source Upgrade Project Final Design Report
The Advanced Photon Source (APS) at Argonne National Laboratory is a world leading synchrotron source of high energy x-rays, one of five light sources operated ...
[22]
Insertion device operating experience at the Advanced Photon Source
The Advanced Photon Source has 29 insertion devices (IDs) installed in the 7 GeV electron storage ring; 28 of these devices, most of which are 3.3 cm period ...<|separator|>
[23]
Proposed APS-U Technical Parameters - Advanced Photon Source
Jan 2, 2016 · Table 3 lists the storage ring beam parameters at the ID source point for the APS-U timing mode with the 48 bunch and the brightness mode with ...Missing: circumference | Show results with:circumference
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Beamlines | Advanced Photon Source - Argonne National Laboratory
Nov 10, 2024 · The Advanced Photon Source consists of 34 sectors; each sector contains one or more beamlines. There are several resources available to help you ...
[25]
[PDF] Beam Stability at the Advanced Photon Source - JACoW.org
Beam stabilization efforts at APS have undergone a continuing process of evolution in order to meet the stability requirement challenge and are summarized here.
[26]
[PDF] Advanced Photon Source Booster Synchrotron Beam Position ...
The Advanced Photon Source operates in top-up mode, which adds charge to the storage ring every two minutes to maintain the current at 102 ± 1.0 mA. This ...
[27]
[PDF] -(O~t08)2/2 - Advanced Photon Source
Bending Radius p. 38.9611 m. The total radiation power from one BM is 1.267 ... x-axis is in the radial direction of the storage ring. The difference in.
[28]
[PDF] The Advanced Photon Source
The PAR is a 30.7-meter circumference storage ring, the design of which is inspired by the positron intensity accumula- tor (PIA) ring; its lattice has ...
[29]
[PDF] The Extended Touschek Lifetime - Advanced Photon Source
The main contributions to the total beam lifetime (which is the inverse of the loss rate) come from residual gas scattering and Touschek scattering. The ...
[30]
[PDF] Fast Facts about the APS - Advanced Photon Source
Facility construction started in spring 1990, and was completed on time and under budget; research started in the fall of 1996.Missing: history | Show results with:history
[31]
[PDF] BENCHMARKING OF TOUSCHEK BEAM LIFETIME ... - OSTI.GOV
BENCHMARKING OF TOUSCHEK BEAM LIFETIME CALCULATIONS. FOR THE ADVANCED PHOTON SOURCE∗. A. Xiao, B. Yang, ANL, Argonne, IL 60439, USA. Abstract. Particle loss ...
[32]
Using the Universal Proposal System (UPS)
Oct 7, 2025 · The Advanced Photon Source is an Office of Science User Facility operated for the U.S. Department of Energy Office of Science by Argonne ...
[33]
[PDF] WISTRESCfinalreport2 - Advanced Photon Source
Sep 6, 2025 · expand the diversity vision of the Laboratory to encompass other groups underrepresented in science and technology. Data presented in this ...
[34]
Introduction to APS | Advanced Photon Source
Feb 12, 2021 · The machine operates for 3 three-month runs (or cycles) each year, with a one-month shutdown between runs. The runs typically span February to ...
[35]
APS Operational Statistics - Argonne National Laboratory
This page provides access to operational statistics for the APS. Statistics have been kept beginning in the fourth quarter of FY 1996.Missing: first | Show results with:first
[36]
[PDF] conducting research and operator training while maintaining top-up ...
The Advanced Photon Source at Argonne National. Laboratory is a high-brightness, third-generation synchrotron light source. It is operated in top-up mode.Missing: off | Show results with:off<|control11|><|separator|>
[37]
Information for Users | Advanced Photon Source
Oct 21, 2024 · GUPs remain valid for up to two years or until they have used up the amount of beam time that was allocated to them. If a GUP is not allocated ...
[38]
Required Training for Users | Advanced Photon Source
Oct 16, 2025 · ALL PERSONS ACCESSING THE EXPERIMENT HALL FLOOR (excluding persons on a tour) MUST WEAR A DOSIMETER. GERT TRAINING IS REQUIRED TO BE ISSUED A ...
[39]
[PDF] ADVANCED PHOTON SOURCE USER ORIENTATION (APS 101)
Oct 19, 2023 · If you are asked to stop work, you must do so. The following information will acquaint you with specific safety precautions at the APS. This ...Missing: protocols | Show results with:protocols
[40]
Welcome | Experimental Support Services at the Advanced Photon ...
General chemistry procedures. Wet chemistry sample preparation. Purification and drying. Solid sample processing (e.g., pelletizing, grinding, homogenization).Missing: site | Show results with:site
[41]
Beamline Controls and Data Acquisition | Advanced Photon Source
Jun 13, 2024 · Through collaboration with APS researchers, we design, develop, deploy, and maintain control system ... caQtDM: EPICS display manager used at XSD ...
[42]
APS Beamline Directory - Advanced Photon Source
APS Beamline Directory · X-ray absorption fine structure · High-energy x-ray diffraction · General diffraction · X-ray absorption near-edge structure.Missing: 71 | Show results with:71
[43]
A wide-field micro-computed tomography detector: micron resolution ...
A custom wide-field lens and a new-generation megapixel camera enabled micro-CT scanning over a 3.5 mm × 5 mm field of view at 1 μm resolution/0.5 μm pixel ...
[44]
Techniques | Advanced Photon Source - Argonne National Laboratory
Sep 2, 2021 · Wide Angle X-ray Scattering (WAXS) technique employs a transmission geometry and large area detector(s) to measure grain-averaged quantities.
[45]
Giving batteries a longer life with the Advanced Photon Source
Sep 13, 2024 · Argonne's Advanced Photon Source allows scientists to view the battery's inner working at a molecular level. Four researchers stand and talk ...Missing: applications | Show results with:applications
[46]
Magnetic field improves 3D-printed alloys | Advanced Photon Source
Feb 26, 2025 · Additive manufacturing, also known as 3D printing, allows engineers to build mechanical parts with complex designs and fine details not ...Missing: industrial | Show results with:industrial
[47]
Structural Biology Center - Argonne National Laboratory
The Advanced Photon Source is an Office of Science User Facility operated for the U.S. Department of Energy Office of Science by Argonne National LaboratoryAbout · Facilities · User Program · SBC Resources
[48]
[PDF] Advanced Photon Source Strategic Plan
In operation since 1996 as a third-generation synchrotron, the APS has served an increasingly large user community of almost 6,000 unique users in a typical ...<|separator|>
[49]
Striking gold: Advanced Photon Source enables catalysis research ...
Dec 21, 2020 · By examining tiny particles of gold with powerful X-ray beams, scientists hope they can learn how to cut down on harmful carbon monoxide emissions from motor ...
[50]
Improved precision in As speciation analysis with HERFD-XANES at ...
Sep 1, 2022 · Accurate speciation of As in mine waste materials is important for understanding the mobility and toxicity of As in near-surface environments.
[51]
Reliability Characterization and Failure Analysis of Next-Generation ...
It increases reliability of testing by up to 80 percent for power electronics in extreme harsh environments. Using Argonne's Advanced Photon Source (APS) ...
[52]
Using X-rays and additive manufacturing to print tough materials
Mar 23, 2023 · Scientists used the Advanced Photon Source to help direct the generation of 17-4 PH stainless steel, a durable metal with many industrial uses.
[53]
Full article: COVID-19 Research at the Advanced Photon Source
Nov 22, 2021 · Researchers using the APS determined over 70 crystal structures of coronavirus proteins and proteins in complex with inhibitors and antibodies.
[54]
Advanced Photon Source Upgrade Sets the Foundation for Discovery
Jul 18, 2024 · The Advanced Photon Source at Argonne National Laboratory recently underwent an upgrade that will make it more powerful than ever before.
[55]
2009 Chemistry Nobel to APS Users | Advanced Photon Source
Jul 10, 2009 · The 2009 Nobel Prize winners used data from APS to study the ribosome, which the APS's x-ray beams enabled them to view at a high resolution.
[56]
Advanced Photon Source lights the way to 2012 Chemistry Nobel
Oct 10, 2012 · Stanford biochemist Brian Kobilka shared the 2012 Nobel Prize in Chemistry for his work in determining the structure of this activated GPCR using X-rays ...
[57]
Nobel Prize winner conducted protein folding research at Advanced ...
Oct 9, 2024 · The scientist awarded the 2024 Nobel Prize in Chemistry for using computer software to invent a new protein used supercomputers and ultrabright X-rays.Missing: contributions | Show results with:contributions
[58]
Bringing discoveries to light: X-ray science at Argonne
Aug 3, 2021 · Argonne researchers are using the laboratory's Advanced Photon Source to discover the structure of viral proteins using X-ray crystallography.
[59]
Pivotal battery discovery could impact transportation and the grid
Mar 23, 2022 · This research used resources of the Advanced Photon Source, a U.S. ... degradation mechanisms in operation from aged Li ion batteries.
[60]
Continuous and discontinuous quantum phase transitions in ... - PNAS
Jan 30, 2012 · This continuous quantum phase transition occurs at P = 2 GPa, followed by a first-order transition at P approximately 4.5 GPa.
[61]
Argonne X-rays light the way to more stable solar cell materials
Jan 23, 2024 · By tracking the movement of ions in perovskites, scientists hope to discover how to prevent solar cell degradation in a new kind of solar cell.Missing: 2020s | Show results with:2020s
[62]
Silica nanodepletors: Targeting and clearing Alzheimer's β-amyloid ...
Mar 9, 2020 · This research used resources of the Advanced Photon Source, a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by ...
[63]
Leading AIDS Drug Has Roots in The Advanced Photon Source
Kaletra®, one of the most successful drugs used to stop the progression of the HIV virus into AIDS, got its start at the U.S. Department of Energy Office of ...Missing: development | Show results with:development
[64]
[PDF] Conceptual Design Report Advanced Photon Source Upgrade Project
May 30, 2011 · ... Energy Tomography Beamline [U1.02.04.06] ........................ 4 ... electron beam-induced current. EBS electron backscatter contrast.
[65]
Beam parameters for various running conditions
The emittance and coupling for the most common running condition (lower-emittance) are 2.5 nm-rad and 0.01, respectively. The values may vary during the run ...
[66]
[PDF] Status of the APS-U Project - JACoW
Building any ultralow emittance 4th generation storage ring light source understandably presents many challenges in accelerator physics and technology.
[67]
DOE Gives “Green Light” to Upgrade Argonne's Advanced Photon ...
Jul 29, 2019 · DOE's Critical Decision 3 (CD-3) milestone approval is a significant recognition of DOE's acceptance of Argonne's final design report for ...
[68]
DOE CD-1 Approval | Advanced Photon Source
May 2, 2016 · CD-1 approval follows a two-year period in which the Upgrade Project prepared a technical design and formulated cost and schedule estimates. ...Missing: timeline | Show results with:timeline
[69]
DOE Gives “Green Light” to Upgrade Argonne's Advanced Photon ...
Jul 29, 2019 · ... Advanced Photon Source (APS), a premier national research facility ... Led to two Nobel Prizes (and contributed to a third);; Supported ...<|control11|><|separator|>
[70]
Vacuum System Installation Points Toward Completed Modules for ...
Nov 28, 2022 · Vacuum System Installation Points Toward Completed Modules for the APS Upgrade Storage Ring. Assembling the new storage ring for the Advanced ...Missing: international | Show results with:international
[71]
APS Upgrade Installation Period Scheduled to Begin April 17, 2023
May 10, 2021 · The year-long storage ring installation and commissioning period for the Advanced Photon Source Upgrade Project is now scheduled to begin April 17, 2023.
[72]
APS Upgrade Update: April 2024 - Advanced Photon Source
Apr 29, 2024 · Almost exactly a year ago, we shut down the Advanced Photon Source (APS) to begin removing the original electron storage ring and installing ...
[73]
Upgraded APS Update: September 2025 | Advanced Photon Source
Sep 30, 2025 · We now have 49 beamlines accepting users for early experiments, with 32 of those in the general user program, and we're seeing hundreds of you ...Missing: beam type positron
[74]
Completing the APS Upgrade: Our Path Forward
Sep 28, 2022 · This great progress has been made in spite of ongoing challenges presented by the COVID-19 pandemic and subsequent supply chain disruptions.
[75]
Magnet Measurement Challenges for the APS Upgrade Project
May 7, 2017 · Abstract: The APS upgrade (APS-U) project will require building and installing more than 1300 new magnets for the storage ring.Missing: MBA fabrication precision international
[76]
[PDF] Magnetic measurements of the Advanced Photon Source Upgrade ...
Sep 26, 2019 · The upgrade of the Advanced Photon Source (APS) at Argonne will require measurements of ~1350 magnets for the new storage ring. ▫ A new ...
[77]
Advanced Photon Source Upgrade - Argonne National Laboratory
An extensive upgrade will be able to generate X-rays that are up to 500 times brighter and enable science we cannot yet imagine.
[78]
APS Upgrade Update: October 2024 | Advanced Photon Source
Oct 30, 2024 · The Advanced Photon Source is now in a very interesting hybrid stage. On the one hand, users are back at a number of our beamlines and early ...Missing: minimizing downtime
[79]
APS Upgrade Update: September 2024 | Advanced Photon Source
Sep 30, 2024 · The first full user run of the upgraded APS era began on September 16. Our doors have re-opened, and initial science is happening at this updated facility.<|control11|><|separator|>
[80]
New Storage Ring | Advanced Photon Source
Mar 30, 2022 · The new storage ring will make use of a swap-out technique for injecting electrons, constantly replenishing the beam as it circulates. New ...Missing: complex linac booster
[81]
Upgraded APS Update: January 2025 - Advanced Photon Source
Jan 31, 2025 · This is also the year we plan to finish the APS Upgrade Project, completing seven new feature beamlines that have been designed to make full use ...Missing: October | Show results with:October
[82]
Upgraded APS Update: October 2025 | Advanced Photon Source
Oct 30, 2025 · Our usual agreement is for 5,000 hours, and we devised the schedule to allow for 4,896 hours, which covers our need for additional time for ...
[83]
[PDF] APS upgrade: Commissioning the world's first light source based on ...
The APS Upgrade project set an orbit stability require- ment of 10% of the electron beam size. To meet this stringent specification, the original plan included ...
[84]
Scenes from the first user run of 2025 | Advanced Photon Source
Jun 3, 2025 · From January to May, the APS hosted users at 41 of the 72 beamlines, and many other beamlines began moving through the commissioning process to ...
[85]
Upgraded APS Update: August 2025 | Advanced Photon Source
Aug 29, 2025 · One year ago this month, we measured the electron beam emittance of the new machine (which had been operational for several months) and ...
[86]
The Advanced Photon Source Strategic Plan
Feb 27, 2025 · The Advanced Photon Source Strategic Plan 2025-2029 is now available for viewing. The Strategic Plan charts the path for the improvements and ...Missing: expansion | Show results with:expansion