CHESS Update June 9, 2020 J oel Brock, Director Cornell High Energy Synchrotron Source (CHESS) jdb20@cornell.edu
CoVID-19 Date Event March 16 CHESS / CESR shut down – only personnel performing “essential maintenance” allowed on Cornell University campus. April 29 CHES S/ CESR receives permission to restart for a single “essential” CoVID-19 research project. (See Cerione talk this evening!) Begin process of restarting accelerator complex. M ay 15 All DoD and NIH funded research determined to be “essential.” Expand planning and preparation for additional experiments. M ay 27 NYS opens T ompkins County for all research. June 10 CoVID-19 research in 7A (Bio-SAXS ) and 7B2 (FLEX). DoD research in 1A3 (FM B) and 3A (FAST). Other beamlines preparing for (remote) operations in Fall 2020. June 29 End of Spring 2020 run, beginning of S ummer down. Focus on preparing for (remote) operations in Fall 2020. (see talk by Elke Arenholz) Labor Day End of Summer down and beginning of Fall operations (user beam on September 23) We expect CHESS will continue to re-open in a phased fashion: first for remote access, then local users, then national users, then international users. There is no time-table. There may be set backs. The virus will determine the rate of progress. Joel Brock | User Meeting | June 9, 2020 2
National Conversation on Race and Racism We are in a time of profound societal change – change that we, as a community and a society, have the power to influence and to shape. We can, and we will, rise to this challenge. Our own consciences demand it, as do our values as a community, and our ethos as Cornellians. President M artha Pollack Joel Brock | User Meeting | June 9, 2020 3
2019-2020: A year of Success • Return to operations • 1 st year of partner model • PREM partnership • Steady progress for CESR • Science! • New technology • New Beginnings Joel Brock | User Meeting | June 9, 2020 4
Return to operations 1) CHESS-U upgrade to CESR (completed January 2019 – stored e + beam) 2) CHESS-U upgrade to X-ray experimental floor (completed June 2019 – x-ray beam in hutches) 3) Reorganization/ restart of CHESS User Operations (completed October 2019 – users doing science) Joel Brock | User Meeting | June 9, 2020 5
1 st Y ear of Operations under Partner Model • Center for High Energy X-ray Science (CHEXS): National Science Foundation • QM 2, F AS T , PIPOXS , HP-BIO (M X & SAXS), X-Ray R&D, Education & Outreach • M aterials Solutions Network – CHESS (M SN-C): Air Force Research Laboratory • SM B, FM B, ITAR • M acro-M olecular Crystallography at CHESS (M acCHESS ): National Institutes of Health and NYSTAR • FLEX (Room-T emperature Serial, M X, HP-M X), Bio-SAXS (SEC) Joel Brock | User Meeting | June 9, 2020 6
1 st PREM with a National Facility as Partner CIE 2 M is a partnership between 2019 2019 Sum Summer r Progr ogram am University of Puerto Rico – Río Piedras Campus Universidad Ana G. M éndez – Cupey and Gurabo Campuses Cornell High Energy S ynchrotron Source (CHESS) Pedro Trinidad M arisol Figueroa Ángel García Kálery La Luz Joel Brock | User Meeting | June 9, 2020 7
Steady Progress for CESR • Machine current during user opera � ons increased from 50 → 75 → >100mA @ 6.0GeV – lifetime ~20 hr • M achine current during machine studies has achieved 200mA (CHESS- U goal) • M ust complete detailed radiation and thermal surveys in X-ray regions of lab before user operations. • Development of novel timing modes (See talk by Jim Shanks) Joel Brock | User Meeting | June 9, 2020 8
To Twin or Not to Twin: M icromechanical Response in M agnesium probed with High Energy X-Rays A. D. M urphy-Leonard et al ., University of M ichigan; D. Pagan, CHESS; What did the scientists discover? The structural evolution of extruded M g was investigated using in- situ high energy X-ray di ff raction (HEXD) at CHESS under fully- reversed low cycle fatigue conditions. At cyclic strains greater than 0.5%, twinning occurs during the compression portion of the cycle and, at early stages of fatigue, most twins are detwinned under reversed loading during the tensile portion of the cycle. As the number of fatigue cycles increases the twin volume fraction increases and the detwinning process is incomplete and a signi fi cant fraction of residual twins remains throughout an entire Twins formed during compression cycle. are removed during tensile loading. 250 This is referred to as twinning. Why is this important? Twins are initiated during Reducing the weight of vehicles translates into energy compressive loading. conservation in transportation which is beneficial for economic Circles outline areas of interest. and environmental reasons. M agnesium shows promise as lightweight but strong material to be used in vehicles since it has Evolution of diffracted intensity from basal lattice planes during low-cycle fatigue of pure magnesium. An increase in intensity from lattice planes perpendicular to 2/ 3 the density of aluminum and an excellent strength-to-weight loading during compression is indicative of twinning, while a decrease is related ratio. However, before it can be widely adopted, its performance to detwinning. Grain orientation maps were collected using electron back-scatter during cyclic loading, i.e. fatigue, must be understood. diffraction to help visualize twinning and detwinning during cyclic loading. CHESS was supported by NSF under award DM R-1332208. CHEXS is supported by NSF under award DM R-1829070.
To Twin or Not to Twin: M icromechanical Response in M agnesium probed with High Energy X-Rays A. D. M urphy-Leonard et al ., University of M ichigan; D. Pagan, CHESS; What are the broader impacts of this work? Experiments like the one presented here advance our understanding of the fatigue characteristics of magnesium and will enable its use as strong, lightweight material in vehicles and related applications. Why did this research need CHESS? The ability to preform high energy X-ray di ff raction (HEXD) experiments during in-situ cyclic mechanical loading at the F2 Station at CHESS were crucial for this research. The sample was illuminated by a 61.332 keV X-ray beam and the di ff racted intensity was measured in transmission on an area detector. A su ffi cient number of grains were illuminated such that nearly complete Debye-Scherer powder rings were captured on the detector. The cyclic loading was performed in displacement control with displacement end points. How was the work funded? CHESS was supported by NSF award DM R-1332208. A. D. M urphy- Leonard acknowledges the support of the National Science Foundation Schematic of the di ff raction experiment detailing the sample geometry. An example of the continuous di ff raction rings and Fellowship. Part of this work is supported by DOE-BES, Division of the HEDM integration areas (Red boxes) are also shown. M aterials Science and Engineering under Award #DE-SC0008637. CHESS was supported by NSF under award DM R-1332208. CHEXS is supported by NSF under award DM R-1829070.
Synergis � c Co − M n Oxide Catalyst for Oxygen Reduction Reactions Yao Yang et al ., Cornell University; Wuhan University What did the scientists discover? Identifying the catalytically active site(s) in the oxygen reduction reaction (ORR) is critical to the development of fuel cells and other technologies. Researchers employed synchrotron-based X-ray absorption spectroscopy (XAS) at CHESS to investigate the synergistic interaction of bimetallic Co 1.5 M n 1.5 O 4 / C catalysts – which exhibit impressive ORR activity in alkaline fuel cells – under real-time operando electrochemical conditions. Under steady state conditions, both M n and Co valences decreased at lower potentials, indicating the conversion from M n-(III,IV) and Co(III) to M n(II,III) and Co(II), respectively. Changes in the Co and M n valence states are simultaneous and exhibited periodic patterns that tracked the cyclic potential sweeps. Why is this important? As an emerging candidate for energy-conversion devices, alkaline fuel cells have drawn increasing attention enabling the use of nonprecious metal electrocatalysts, Schematic of the in situ XAS electrochemical cell. Working electrode rather than the expensive Pt-based catalysts. Among these, 3 d metal oxides have (WE, catalyst on carbon paper) and counter electrode (CE, carbon rod) garnered increasing interest as ORR electrocatalysts due to their high activity, long were immersed in 1 M KOH solution. The reference electrode was durability and low cost. However, the limited understanding of the complicated connected to the cell by a salt bridge to minimize IR drops caused by electrocatalytic mechanism of ORR on these materials has hindered the progress. the resistance in the thin electrolyte layer within the X-ray window. Researchers at CHESS investigated a highly active 3 d bimetallic electrocatalyst Co– M n oxide and, based on in situ XAS measurements, and propose that Co and M n serve as synergistic sites to catalyze ORR. J. Am. Chem. Soc. 141, 1463 (2019) DOI: 10.1021/ jacs.8b12243 CHESS was supported by NSF under award DM R-1332208. CHEXS is supported by NSF under award DM R-1829070.
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