About

An inclusive process involving ALS and ALS-U staff, the ALS user community, and external advisory committees was undertaken to select the insertion-device beamlines that will be built and upgraded within the scope of the ALS-U Project. These beamlines will join existing ALS beamlines to form the full complement of capabilities that will be available at the upgraded ALS in several years.

The ALS-U Project will build two new beamlines:

• a soft x-ray beamline in Sector 10, dubbed “FLEXON,” whose high-brightness coherent flux and multiple complementary techniques will probe the roles of multiscale heterogeneity in quantum materials; and

• a tender x-ray beamline in Sector 8, whose coherent scattering and scanning spectromicroscopy capabilities will address challenges at the frontiers of diverse scientific areas, ranging from soft condensed matter and biomaterials to energy science and Earth and environmental sciences.

The project will also upgrade two existing soft x-ray beamlines in Sector 7:

• COSMIC (7.0.1), which will leverage the full brightness and coherence of the upgraded ALS to perform zone-plate-based microscopy, ptychography, and 3D tomography with an up to hundred-fold increase in measurement speed and an improvement in spatial resolution down to 1 nm; and

• MAESTRO (7.0.2), which will take full advantage of the improved coherence of the upgraded ALS to improve the angle-resolved photoemission spectroscopy (ARPES) collection efficiency by more than an order of magnitude, enabling much better spatial resolution, faster measurements, and more comprehensive data sets for materials discovery.

These beamlines, described in more detail in this document, were selected from among a number of strong proposals put forward by teams of ALS scientists, leveraging critical input from the user community. Several advisory committees provided feedback that informed the outcome, most notably an ad hoc committee of external experts who thoughtfully evaluated the proposals for scientific importance, relevance of ALS-U characteristics and potential world leadership, technical feasibility and fit to project resources, and strength of the relevant user community and expected productivity.

The selection criteria for determining these beamlines were:

• Scientific importance

• Relevance of ALS-U characteristics and potential world leadership

• Technical feasibility and fit to project resources

• Strength of the relevant user community and expected productivity

Coming out of the workshop, we hope to have the information needed to answer the following questions:

• What are the key scientific questions to address with this nanoprobe and what sample environments are required?

• What is the optimum endstation design? We are currently considering two main options: one using custom sample environments and one using commercial sample environments. The former could provide optimum environments for specific classes of materials with considerable development, while the latter may restrict some sample geometries but would allow faster deployment.

• Which contrast mechanisms should be the highest priority for optimization? The options are ptychography absorption spectroscopy, fluorescence imaging/spectroscopy, diffraction and phase contrast. Are there other options?

• What are the pros and cons of various detector options in this energy range? Currently, the three detectors under consideration are the LBNL FastCCD, the Dectris PILATUS, and the Paul Scherrer Institute JUNGFRAU.

Dula Parkinson, Advanced Light Source, LBNL

David Shapiro, Advanced Light Source, LBNL

Sirine Fakra, Advanced Light Source, LBNL

Martin Kunz, Advanced Light Source, LBNL

Rich Celestre, Advanced Light Source, LBNL

Matthew Marcus, Advanced Light Source, LBNL

Harold Barnard, Advanced Light Source, LBNL

Administrative Support:

Andrea Taylor, ALS, LBNL

Amanda Espiritu, ALS, LBNL