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Materials Measurement Science Division

INTRODUCTION

The mission of the Materials Measurement Science Division (MMSD) is to ensure and promote excellence in measurement science. MMSD conducts mission-based fundamental research, standards production, and applied science and engineering. MMSD provides measurements for the determination of structure, composition, and properties of materials. Its Standard Reference Materials (SRMs) and Standard Reference Data (SRD) are used to validate methods and to enable new technologies. MMSD provides state-of-the-art instrumentation, methods, models, and software to measure materials over a range of length and time scales. MMSD projects and programs are well aligned with the mission of the NIST Material Measurement Laboratory (MML).¹

MMSD has five major technical program areas. These programs are centered around core competencies that represent the expertise of the division. Each program consists of multiple projects and most are designed to be intra-divisional collaborations. The five program areas are (1) Atomic Arrangements and Structure–Property Relationships, (2) Physical Chemical and Mechanical Properties of Materials, (3) X-Ray Scattering and Spectroscopy, (4) Materials and Metrology for Safety, Security and Forensics, and (5) Informatics and Artificial Intelligence for Materials Design. MMSD conducts research to enhance its core capabilities and to promote innovation. The division has a balance between basic research, which is published in peer-reviewed journals, and technical projects that serve the standards and regulatory mission of NIST and requests from other stakeholders.

MMSD currently has 99 federal employees and 51 associates (contractors and guest scientists), making it one of the larger divisions. The majority of MMSD personnel are located at the NIST main campus in Gaithersburg, Maryland, where they are distributed primarily across three campus buildings. Six of the federal employees and four of the associates that are part of MMSD are located at the National Synchrotron Light Source II facility (NSLS-II) at Brookhaven National Laboratory in Upton, New York. From a funding perspective, MMSD receives 25 percent of its support from seven U.S. government agencies outside of the Department of Commerce.² These external collaborations are an important mode of dissemination of expertise and technology.

Three areas targeted for future growth are (1) ceramic additive manufacturing, (2) producing high-quality, machine-readable data sets, and (3) autonomous experimentation.

MMSD is organized into nine organizational units—the division office and eight technical groups based on technical expertise, but collaborations across groups are commonplace.

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¹ R. David Holbrook, 2020, National Institute of Standards and Technology (NIST), “Materials Measurement Science Division: NASEM Panel Review,” presentation to the panel, September 9.

² Ibid.

ASSESSMENT OF TECHNICAL PROGRAMS

A brief assessment of the technical work is presented below. The discussion is organized around each of the eight technical groups in MMSD.

Accomplishments

The Nanomechanical Properties Group (643.09) develops nano-scale measurement metrology and manages a laboratory dedicated to nanomechanics. Work includes equipment development and the calibration and control of mechanical properties. Measurements are performed at small scales and on small-scale phenomena. Property measurements include elastic modulus, plastic yield stress and fracture toughness, strength measurement, and strain and stress measurements. This group develops reference materials and measurement protocols for a number of both static and dynamic nanoproperty techniques, including high-resolution electron backscatter diffraction and scanning probe microscopy.

The Materials Structure and Data Group (643.08) develops and broadly disseminates measurement science, standards, and technology for the determination of the structure of advanced materials across a broad range of length scales. The group uses and develops in-house characterization tools and extensively exploits national user facilities for both synchrotron X-ray and neutron scattering. The group members determine, compile, evaluate, and disseminate key data and computational tools needed to establish the relationships between structures and performance of inorganic and hybrid materials and devices. One project includes developing machine-readable crystallographic descriptions to translate symbolic data into a format suitable for artificial intelligence (AI) applications. New projects have been initiated in development of 4D scanning transmission electron microscopy (4D STEM) electron diffraction, additive manufacturing, and advanced gas sorbent materials.

The Synchrotron Science Group (643.06) develops and disseminates state-of-the-art synchrotron X-ray measurement science, standards, and technology for the determination of the structure of advanced materials. Located at the NSLS-II, the group develops and maintains three high-throughput beamlines that provide timely access to X-ray facilities to support NIST priority programs. It also supports the broader scientific community as part of the NSLS-II General User Program. It is currently developing two resonant soft X-ray microscopy beamlines.

The Microscopy and Microanalysis Research Group (643.02) “performs fundamental research and develops metrology towards the compositional and morphological characterization of materials from the mesoscale to the atomic scale using electron, ion, and photon interactions with matter.”³ The group determines composition and structure of nanomaterials and conducts comprehensive analysis, modeling, and theoretical methods to support stakeholder needs to advance microanalysis in diverse areas of materials, biological, and forensic sciences. They further maintain a microscopy facility.

The Nanomaterials Research Group (643.03) develops metrology to advance nanomaterials research and applications in emerging areas (e.g., nanomedicine, nanotherapeutics, nanoplastics). Measurement science is used to determine physical and chemical properties of materials in the nanoscale regime. The group develops physical and/or documentary standards related to nanomaterials, particle sizing, and surface analysis.

The Materials for Energy and Sustainable Development Group (643.04) “develops and disseminates measurement science, measurement standards, and measurement technology that pertains to the measurement of functional properties of advanced energy related materials.”⁴ This work encompasses chemical, electrical, thermal, and magnetic properties, materials efficiency, and critical materials. New

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³ Keana Scott, Group Leader, NIST, 2020, “Microscopy & Microanalysis Group: 643.02,” presentation to the panel, September 10.

⁴ NIST Material Measurement Laboratory (MML), 2020, “National Academies of Sciences, Engineering, and Medicine: 2020 Assessment Read-Ahead Materials for September 9-11, 2020,” Gaithersburg, MD, p. 78.

themes include sustainability and the circular economy, the materials data infrastructure, and innovations in AI.

The Surface and Trace Chemical Analysis Group (643.05) develops, improves, and standardizes analytical techniques used for the elemental, molecular, isotopic, radiological, and morphological characterization of surfaces, thin films, and particles. The group also develops novel methods of chemical analysis based on optical microscopy, mass spectrometry, chromatography, ion mobility spectrometry, optical spectroscopy, autoradiography, and nuclear counting techniques. This group supports the NIST mission in safety, security and forensics.

The Security Technologies Group (643.10) conducts research to advance and develop the measurement science for trauma-mitigating materials and materials systems to identify concealed threats and contraband and to support the development of performance-based standards in the same area. Further, this group performs research on fundamental structure, properties, and performance to support innovation and advanced manufacturing of high-strength textiles, nanocomposites, and blunt-trauma-reducing materials.

Challenges and Opportunities

The members of MMSD are extremely capable and productive in the broad area of materials measurement science. Their work is well aligned to the mission of NIST. The technical programs represent a balance of high-end research in measurement science and technology and support of commerce through stakeholder engagement. Research focus on nanoscale measurements and materials is providing exciting new knowledge of materials and enabling new avenues for materials fabrication, characterization, synthesis, and applications.

The new effort focusing on separation, characterization, and quantification of soft materials has progressed well and is an area for growth. Likewise, the success of the Nanomedicine Collaboratory points the way to additional collaborations.

FINDING: The development, fabrication, and sale of SRMs and documentary standards are central to the mission of MMSD. Although MMSD has a broad client base for SRMs, etc., the contacts are handled by other groups in the MML.

RECOMMENDATION 6-1: The Materials Measurement Science Division (MMSD) should increase the degree to which it utilizes its customers for feedback on new products and information with regard to emerging opportunities. To this end, the Material Measurement Laboratory should utilize a process for obtaining feedback. MMSD should increase its interaction with the offices managing sales of such products at NIST.

FINDING: In 2017, MMSD initiated a new effort focusing on the separation, characterization, and quantification of nanoscale soft materials (including plastics) by adopting previously developed methods and by investigating new approaches.

FINDING: The shift in emphasis toward nanoscale soft materials is an excellent area for growth but may require new equipment and expertise, because the group was previously focused primarily on hard materials.

FINDING: The group name for the Materials for Energy and Sustainable Development Group seems to be outdated. While there is research on energy materials, the increasing focus of the group appears to be in the area of high-throughput materials, materials data, and autonomous materials science.

RECOMMENDATION 6-2: The Materials Measurement Science Division should evaluate whether to move some of the work of the Materials for Energy and Sustainable Development group (e.g., X-ray Metrology) to another group (e.g., Materials Structure and Data Group) and refocus the former group’s efforts on materials data and artificial intelligence approaches.

The Security Technologies Group still appears to be a bit of an outlier in the division, but clearly progress has been made to engage the work of the group into a cross-cutting research program that includes the following: (1) Atomic Arrangements and Structure–Property Relationships, (2) Physical Chemical and Mechanical Properties of Materials, and (3) Materials and Metrology for Safety, Security, and Forensics. There are additional opportunities for the Security Technologies Group to better exploit the extensive materials characterization capabilities of the other groups in the division.

PORTFOLIO OF SCIENTIFIC EXPERTISE

Accomplishments

At the time of the panel’s review, MMSD staff consists of 87 scientists, 1 NIST fellow, 3 technicians, 2 administrative personnel, 6 support personnel, and 51 associates.

The Nanomechanical Properties Group core expertise includes the application of techniques to explore materials properties at the nanoscale. Techniques include scanning probe microscopy, nanoscale force spectroscopy, colloidal probe force spectroscopy for strength measurements, high (angular) resolution electron back-scattered diffraction, contact resonance AFM (atomic force microscopy), Raman microscopy, cathodoluminesence spectroscopy, X-ray diffraction, fluorescence spectroscopy, and coherent gradient sensing interferometry for accurate strain and stress measurements.

The Material Structure and Data Group members are experts in all major techniques of structural analysis—various modes of X-ray/neutron scattering, X-ray absorption spectroscopy, impedance spectroscopy EPR (electron paramagnetic resonance), EXAFS (extended X-ray absorption fine structure, TEM (Transmission electron microscopes), 4D-STEM, EELS (electron energy-loss spectroscopy), XEDS (Energy-dispersive X-ray Spectroscopy), and modeling.

The NSLS-II National User Facility reached full operation in November 2019. The X-ray beamlines probe the structural, chemical, and electronic properties of a wide range of materials. The facility features seven experimental stations and two unique dual beam stations. Measurements include near edge X-ray absorption fine structure (NEXAFS), hard X-ray photoelectron spectroscopy (HAXPES), and resonant soft X-ray scattering (RSOXS) with a novel data collection/analysis capability. Techniques are applicable to the new thrust in soft materials and, more generally, provides capabilities that are accessed by a broader user group.

The Microscopy and Microanalysis Research Group has expertise in a wide range of microscopy methods for application in compositional and morphological characterization of materials from the atomic to the mesoscale. Advanced measurement methodologies are achieved through expertise in maintaining, modifying, enhancing, and building state-of–the-art facilities.

The Nano Materials Research Group has expertise in a diverse array of techniques and specializations, including particle sizing, nanomaterials and organic ligand synthesis, surface chemical analysis, soft materials, atmospheric aerosols and microparticle analysis, and applications and growth of nanocrystals and nanowires. Skills are being applied to develop metrology to advance nanomaterials research and applications. Examples are metrology for soft nanomaterials and the link between structure and properties at the nanoscale.

The Materials for Energy and Sustainable Development Group has expertise in energy conversion materials and techniques, high-throughput experimentation, recycling and sustainability, X-ray metrology and standards, materials data, and autonomous materials science.

The Surface and Trace Chemical Analysis Group has expertise across a wide range of techniques applicable to measurement, technique development, materials handling, and standards creation for the characterization of particles, surfaces, and thin films. This expertise in metrology finds applications in safety, security, and forensics, including trace contraband detection and worker safety.

The Security Technologies Group has expertise in metrologies for property determination of high-performance materials and the advancement of technologies applied to security imaging. Performance-based standards are built on new technologies and knowledge of materials properties and structure.

FINDING: The Security Technology Group differs from other groups in MMSD in that its work has a significant focus on current “real-world” issues. Its members recognize the need to target those areas that are most urgent and on changes that can be readily adopted.

Challenges and Opportunities

MMSD staff is excellent and taking good advantage of the unique research environment at NIST to conduct long-term research using state-of-the-art facilities, with talented co-workers, and a wide range of outputs for successful work. One of the staff stated that “impact” is a key metric for measuring output. As such, scientists will need to embrace that metric and measure themselves against it each year. Intradivision collaborations, shared resources, informal assistance, and exchange of ideas is essential to avoid silos and continuity of success. Continued attention will be needed to achieve a culture of sharing, assistance, and collaboration.

RECOMMENDATION 6-3: The Materials Measurement Science Division should conduct additional intra-divisional collaboration, which might be exploited to add fundamental understanding for the benefit of the research component of the work going forward.

ADEQUACY OF FACILITIES, EQUIPMENT, AND HUMAN RESOURCES

Accomplishments: Human Resources

Postdoctoral fellows are an important and significant part of the MMSD workforce that benefits both their scientific career and the MML. MMSD has begun both informal and formal mentorship for postdoctoral fellows. This includes an informal “on-boarding” interview with the division director to discuss NIST culture, projects, and current career plans. Mentorship is continual during the postdocs time at NIST. All mentors understand the importance of publication of work in reputable scientific journals. Attending scientific meetings is encouraged. Significant institutional support networks are available at NIST and external coursework is encouraged. Assistance with preparing for the time when their tenure at NIST ends is also provided. A debriefing interview includes feedback on how the postdoctoral program might be improved. A NIST postdoctoral fellowship can be a valuable career enhancing experience for the postdoc. Postdocs who go on to careers in university, industry, and so on, are one of MMSD’s successful products.

The NIST Summer Undergraduate Research Fellowship (SURF) Program, which sponsors an 11-week summer internship program for undergraduates, provides students with a hands-on research experience. This program was canceled for 2020 due to the global pandemic, and the number of students in 2019 was reduced due to the federal government shutdown. Otherwise, a typical number of students sponsored by MMSD each summer is 16, which is a good number. The support of the scientific staff enables the success of this program.

Challenges and Opportunities: Human Resources

MMSD, as noted before, has 99 federal employees and 51 associates, a decrease from 106 and 85, respectively, from 2017. The major area of decline noted is with the associates, which decreased from 85 in 2017 to 51 at present. The decline in associates reflects the fact that several were hired full time. There was also a decrease in the number of postdoctoral researchers. The decline in the number of scientists in the past 3 years thus appears problematic, considering the need to maintain and grow expertise in critical areas. Further, several scientists are reaching retirement age.

As highlighted in previous assessment reports in 2014 and 2017, there is a dearth of technicians in the division, and a further reduction may need to be addressed. The reduction in the number of associates (primarily in groups 04, 05, 08, and 10) was said to result not in a lower number of work hours, but it was a transition from part-time to full-time associates. While it is not clear what the impact of this transition will be on the division, it may lead to associates taking on roles similar to career staff without the benefits of a permanent position.

RECOMMENDATION 6-4: The management of the Materials Measurement Science Division will need to continue to evaluate and understand the impact of the change in staff numbers and redistribution of workloads. Specifically, there needs to be a shared understanding of the division mission that justifies staff numbers.

MMSD needs continued focus on diversity of the scientific staff, as the division has the lowest percentage of female employees in MML. Addressing this problem at the entry level is necessary, perhaps not sufficient.

FINDING: The MMSD has the lowest female-to-male ratio compared with other divisions in the MML.

RECOMMENDATION 6-5: The Materials Measurement Science Division (MMSD) should examine ways to recruit and retain greater numbers of female scientific staff. MMSD staff should all work to enhance the visibility of NIST as a career option through technical meeting/society activities and university interactions. All team members should ensure inclusiveness and assist with career development of the diverse workforce, including the careers of associates and post docs.

Critical expertise that must be maintained needs to be identified, and action needs to be taken where expertise is at risk, such as with a single employee or an employee close to retirement. Another challenge for MMSD is recruiting new employees and working on employee retention. Recruitment needs to be early and “aggressive.” Research staff can seek opportunities to deliver lectures at universities in order to increase awareness of NIST and NIST career opportunities among the student population. The discussion of high-end research with a view to real-world applications will hold student’s attention. Participation by NIST’s diverse workforce will demonstrate a welcoming and inclusive work environment. Technical society activities also provide opportunities for student engagement.

Employees need opportunities to maintain and grow technical expertise, to interact with the external technical community through participation in technical meetings and workshops, and to be recognized as experts in their field. Also, high performers need to be recognized and be given opportunities for growth within NIST. External recognition of MMSD employees also brings recognition to NIST.

Accomplishments: Facilities/Equipment

The work of MMSD is very equipment-intensive. Instrumentation is used for much of the in-house research. Further instrument improvements, invention of new instrumentation, and recommendations for use are part of enabling stakeholder best practices. NSLS-II is a tremendous national resource that is available to both NIST scientists (50 percent of the time) and the NSLS-II user community.

Challenges and Opportunities: Facilities/Equipment

The division has developed a number of beamlines that are both a NIST and a national resource. Half of the beam time is open to general users and half to NIST users. This facility represents a large investment by NIST in developing synchrotron techniques over the past 20 years. One recent example is a new soft X-ray scattering facility built in part with an Innovations in Measurement Science award ($1.5 million per year for 4 years). This is an exciting new capability. However, there is no clear funding for maintaining this new facility. Additionally, the group is working on two new X-ray microscope beamlines. The funding of this facility may be beyond the expectations of a division. Thus, a funding model at a higher level in the organization may need to be developed.

The project on developing Atom Probe Tomography faces a resource challenge. While this is a productive research area, the project uses a 3D atom probe instrument that is nearing 10 years in age and will need to be replaced or upgraded. This is just one of many important instrument needs of the division and might require better quantification of the impact of equipment development with respect to long-term maintenance.

Overall, the division is challenged by the need to refresh and replace state-of-the-art equipment. Given the current budget limits, this may not be possible for all equipment, and some tough choices will most likely need to be made. The division already extensively uses national user facilities for synchrotron and neutron measurements. This may have to extend to other techniques (e.g., electron microscopy) available at national user facilities for advanced characterization of materials. This cannot easily be done for research programs that are based on modifying, extending, and enhancing the capabilities of metrology equipment. Some effort may need to be made to centralize some equipment to the division level instead of the group level to remove any redundancy in equipment. Similarly, some programs may need to be eliminated if the base equipment becomes out of date and cannot be replaced.

The greatest need is driven by high-cost (>$2 million) instrumentation and funding for facilities at NSLS-II. All equipment needs to be maintained and periodically refreshed. These issues are exacerbated by NIST policies and practices that add cost to purchases and that combine budgets for equipment and operations. Equipment-intensive experimental work relates directly to the NIST measurement science mission and needs to be addressed at the highest levels of NIST. Facilities such as the cleanroom in Building 218—with a low particle environment, temperature stability, humidity stability, and vibration isolation—are an example of the laboratory environment that is needed for certain instrumentation and sample preparation.

The purchasing power of the divisions is impacted first by a 50 percent tax on equipment. This disadvantages equipment purchases for the purposes of budgeting, because the trade-off—versus funding an additional staff position or other expenditures—becomes more acute. Further, the NIST working capital fund model for purchase of new equipment requires payback for any purchase from annual operating funds. This further disadvantages equipment purchases in any discussion of budgeting. Other agencies (such as the National Oceanic and Atmospheric Administration, the Department of Energy, the National Institutes of Health, and the Department of Defense, etc.) place an entry for expensive equipment in their annual budget request and treat equipment funds as separate from operating funds.

FINDING: MMSD recognizes the need for sustainable funding for higher-cost instrumentation (>$2 million) as a division priority. The Synchrotron Science Group has recently developed beam lines at NSLS-II supported by division funds. NIST policies that add cost to purchases increases the burden. Other needs are to address aging buildings and facility requirements for special instrumentation. (See Recommendation 5-3.)

FINDING: The work of MMSD is extremely dependent on access to state-of-the-art instrumentation. New technologies are needed as a group moves into exciting new areas such as soft materials. Other instrumentation is aging and will need replacement in the near future (e.g., 3D atom probe instrumentation and electron microscopes). NIST extensively uses national user facilities beyond MMSD, particularly when instrument development is not a part of the project.

RECOMMENDATION 6-6: The Materials Measurement Science Division should prioritize the division’s needs for upgrading/replacement of equipment and explore centralizing commonly used instrumentation at the division or laboratory level.

DISSEMINATION OF OUTPUTS

Accomplishments

Briefing and background materials presented to the panel showed many noteworthy examples of recognized outputs, such as publications (409 in archival journals, 22 conference papers, 114 NIST reports, and 1 book or book chapter), customer engagement (19 workshops, 8 CRADAs (Cooperative Research and Development Agreements), 2 MTAs (Material Transfer Agreements), 2 NDAs (NonDisclosure Agreements), and 18 IAAs (Inter/Intra-Agency Agreements), standards activities (68 SRMs/RMs, 60 standards committees, and 15 leadership positions), patent and invention disclosures, external recognition, and Department of Commerce and NIST named awards.

MMSD has a clear customer focus. Partnerships with outside organizations account for 25 percent of the MMSD annual budget. These partnerships are with government agencies such as the Department of Homeland Security, the Department of Defense, the Department of Justice, the Consumer Products Safety Commission, and national laboratories. External partnerships also include universities and industry. These partnerships are a mechanism for dissemination of materials and know-how as well as a source of expertise and knowledge for NIST.

During the review period, the number of publications ranged from 151 to 174 peer-reviewed publications. The number of citations for the papers published in 2017 is 1,300, indicating that the papers are being well cited.

MMSD makes a tremendous contribution to the development of SRMs and standards, which are in demand by outside organizations. One example is RM 8012 and 8013 Gold Nanoparticles released in direct response to a request from the National Cancer Institute. The publication of physical and documentary standards is an important output of the division. Examples include “A Standard test Method for Estimating Limits of Detection in Trace Detectors for Explosives and Drugs of Interest” and “Standard Practice for Soft Armor Conditioning by Tumbling.” MMSD scientists serve on standards development committees in a technical capacity both as leaders and as technical content contributors. Members of MMSD also serve in external leadership roles as journal editors, society directorships, and as members and chairs of steering committees. MMSD members have been elected to “fellow” status in a number of scientific societies.

Challenges and Opportunities

One challenge for MMSD is maintaining the availability of a large number of SRMs over a long period of time, while at the same time developing new SRMs. Increasing public awareness of NIST activities, disseminating educational and instructional information, including tutorials, etc., can be used to increase impact. An example is the recent visualization of mask effectiveness in limiting the spread of COVID-19. The division might profitably expand collaboration with the NIST public affairs office.

Within the division, there are a number of examples where new code has been developed to analyze and process experimental data (e.g., OCEAN, RMC Profile, JARVIS, etc.). While this is an impact product that engages the broader materials community, it is difficult to quantify the impact of these codes. One way to quantify such impacts may be to request that the codes be cited in publications with a standard citation, allowing the impact to be tracked. Similarly, a major output of NIST is the development of new measurement capabilities. Again, MMSD will need to track and quantify the adoption of these new approaches in the broader community.