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2 General Assessment of the NIST Center for Neutron Research As it has for more than a decade, the NIST Center for Neutron Research is fulfilling its mission extremely well―that mission is to ensure the availability of neutron measurement capabilities in order to meet the needs of U.S. researchers from industry, academia, and government agencies. For years, including the long period of “neutron drought” in the United States brought about by the closing of the High Flux Beam Reactor (HFBR), the prolonged shutdown of the High Flux Isotope Reactor (HFIR), and earlier problems with the Lujan Facility at the Los Alamos National Laboratory, the NCNR has helped maintain the strength and competitiveness of neutron scattering research in this country. It has done so through a combination of good management, a culture of excellence, new instrumentation, and continuing improvements to the beam lines. The NCNR’s reactor has continued to perform very reliably, with 253 days of availability out of a possible 255 days in the past year. By almost all of the Office of Science and Technology Policy’s performance metrics (e.g., reliability of operation, number of operational days per year, number of instruments, number of users, number of publications, and publications in high-impact journals), the NCNR continues to be the second most scientifically productive neutron facility in the world (comparable to ISIS in England), after the Institut Laue-Langevin (ILL) in France. (The ILL has more than twice as many instruments as the NCNR and consequently has an accepted proposal rate approximately twice that of the NCNR). This is likely to continue at least until the Spallation Neutron Source (SNS) and the Japan Proton Accelerator Research Complex gain full momentum. Even then, with planned upgrades and improvements the NCNR will continue to be a competitive facility for the foreseeable future. The new suite of instruments planned for the expansion includes enhancements to the neutron guides (by optimizing them for specific instruments) and a new cold source and will help to ensure the NCNR’s competitiveness. If expected increases in NIST’s funding in the immediate future materialize, a concomitant personnel increase should be made at the NCNR to meet the needs of this transition. This becomes important when considering this country’s need for neutron scattering research in years to come, given the recent shutdown of the Intense Pulsed Neutron Source and lingering uncertainties about the long-term future of the Los Alamos Neutron Science Center and the HFIR. A good example of how the NCNR has met the needs of U.S. researchers is the agility with which samples of the new Fe-based high-temperature superconductors were run on the appropriate instruments. When scientists from other laboratories approached NCNR staff with samples of these materials, the scattering studies were performed, results analyzed, and a manuscript submitted to a prestigious journal within a few days. The researchers managed to obtain some of the earliest definitive results on the structural and magnetic phase transitions quickly, resulting in immediate scientific impact and numerous citations that have put NCNR personnel and collaborators in a leadership position in the field. Discussions of the Panel on Neutron Research with NCNR users and a review of the user survey conducted by the NCNR User Group (NUG) yielded the conclusion that by and large the NCNR user community is satisfied with access to the NCNR facilities, the NCNR proposal system, the facilities themselves, and the assistance provided by NCNR staff, who are described 6
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by users as “helpful,” “dedicated,” and “mindful of tending to user needs.” Users reported that, as in practically all such facilities, there are certain areas that could be improved―examples include transmitting data to users in a standard format and improving the types and quantities of ancillary equipment (such as high magnetic fields and millikelvin-temperature refrigerators, high-temperature furnaces, pressure cells, controlled-humidity cells, complementary and simultaneous optical microscopy and optical spectroscopy tools, and nuclear magnetic resonance microscopy). Often the availability of one or more of these items, as compared with the availability of neutron flux alone, makes the crucial difference in carrying out experiments in a competitive field. Another challenge that most facilities face is to ensure uniformity for interchangeable use of such tools on different instruments. The NCNR management and staff are mindful of these challenges, and they have allocated substantial effort to developing user- friendly data-analysis programs, although it is not clear how close they are to meeting the ideal of standardized data-processing routines that can be used for experiments at all facilities with trivial modifications. Their strategy of trying to enlist the user community to submit proposals to develop some of these ancillary items of equipment has met with limited success. This result probably points to the fact that the development of sophisticated specialized equipment is generally left to scientific and engineering professionals such as NIST staff, with the selective involvement and collaboration of user scientists. An example seems to be the Multi Axis Crystal Spectrometer (MACS) inelastic spectrometer designed and developed with much involvement by researchers at the Johns Hopkins University, with funding from that university, NIST, and the National Science Foundation (NSF). The sample of research projects provided to the panel suggests that the science done by NCNR scientists is of high quality, as is their expertise in neutron scattering. The encouragement by NCNR management of the scientific activities of its staff is a commendable complement to its related focus on their service to the user community. The instrument scientists have some discretionary time and generally are able to use it effectively. For certain experiments, such as powder diffraction, the staff encouraged many users to send their samples, which could be run by the staff more efficiently than if the users traveled to the NCNR to perform the experiments. Small Angle Neutron Scattering (SANS) users have also been encouraged to send samples to staff to run in short measurements in order to assess feasibility. Of course, while such trends should not be taken to extremes (a cadre of expert users in the community is also essential for the success of the neutron scattering enterprise in the United States), it may be a trend that can be appropriately grown. There seems to be an inclination for some new users, particularly interdisciplinary users, to be somewhat uninterested in developing expertise and sophistication in the techniques of scattering; this makes it imperative to maintain the scientific and technical excellence of the NCNR staff. Nevertheless, in order to generate interest and expertise in the outside scientific community, it continues to be important that NCNR scientists maintain outreach efforts (with an organized presence at major scientific conferences, for example) and increase throughput at the neutron schools that they have been organizing. The facility seems to be serving the needs of industrial users reasonably well, although it should continue to take a proactive role in educating industrial scientists about the unique advantages that neutrons offer in investigating certain problems. There appears to be substantial industrial involvement in the facility, through participating research teams (PRTs) or direct collaboration with NIST scientists. The Polymers Division in NIST’s Materials Science and 7
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Engineering Laboratory in particular has been responsible for much industrial involvement with NCNR programs, many of which use the NCNR facilities as crucial characterization tools. For example, the NCNR has developed collaborations with companies such as Xerox, IBM, Merck and Company, Corning Incorporated, the Dow Chemical Company, Hitachi, and Intel Corporation. In particular, these industrial users seem eager to take advantage of the SANS instruments and reflectometers. A successful example is the Ultra-Small Angle Neutron Scattering (USANS) instrument, which was fairly undersubscribed until an active campaign to advertise its capabilities resulted in many proposals, many of which are from industry. 8