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2 General Assessment of the NIST Center for Neutron Research The timing of this review of the NIST Center for Neutron Research coincided with a time of considerable change for the U.S. neutron community: namely, the coming online of the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory (ORNL) and the approaching 10.5-month shutdown of the NCNR facility for upgrades and the installation of a new guide hall and new instruments. It is, therefore, an appropriate time to put in perspective the role that the NCNR has played in the field of neutron-scattering science in the United States and to discuss the NCNR facility in comparison with other leading neutron sources worldwide. ROLE OF THE CENTER IN THE NEUTRON-SCATTERING COMMUNITY For the past decade, the NCNR can claim to have been the flagship of American neutron-scattering facilities, and it ranked high among all international facilities in neutron scattering. In fact, after the Institut Laue-Langevin (ILL) in France, which is the largest neutron facility in the world (as measured by the number of beam lines and staff), the NCNR is, by almost all measures, the next most productive and effective scientific neutron facility in the world. This is borne out by statistics measuring its performance according to several criteria: number of instruments; number of operating days per year (with a 20-year average of 233 days per year and a record 267 full-power operating days in 2010); number of participants per year; number of publications per year; an enviable safety record;3 a staffing level of 4 or 5 scientists, technicians, and engineers per instrument (acknowledged worldwide as the desirable and required staffing level); and a high level of user satisfaction as shown by surveys of users. The facility, which was originally a research reactor meant at the time to serve the needs of NIST and industry, grew in the 1980s, with the addition of a cold-neutron guide hall, into a true national user facility, driven by the vision of its scientist-managers. Their hands-on and effective management helped to develop the spirit of dedication, efficiency, and scientific excellence that persists to this day. These qualities enabled the NCNR (along with the Intense Pulsed Neutron Source, or IPNS, at the Argonne National Laboratory) to maintain U.S. competitiveness in the field during the long âneutron droughtâ at Department of Energy (DOE) sources in the 1980s and 1990s. That drought resulted from the shutdown of the High Flux Beam Reactor (HFBR), the long periods of shutdown at the High Flux Isotope Reactor (HFIR) at the ORNL, and, during that period, the erratic performance of the Lujan Neutron Scattering Center at the Los Alamos Neutron Science Center (LANSCE) facility. (The IPNS itself was shut down in 2005.) It also opened up an era in which industrial firms including Exxon, DuPont, and others, together with various universities, were able to operate Participating Research Teams at the Cold Neutron Research Facility (CNRF, the original name for the NCNR) 3 National Institute of Standards and Technology, The NIST Center for Neutron Research: 2010 Accomplishments and Opportunities, NIST Special Publication 1110, December 2010. Available at http://www.ncnr.nist.gov/AnnualReport/FY2010/AR_2010_large.pdf. Accessed June 14, 2011. 7
and to use neutron scattering as one of their R&D tools. The presence of several experienced and renowned scientists on the staff of the CNRF who were willing to work closely with these users and to help them with their problems was crucial to the success of this effort. Industrial involvement at the NCNR, which has continued to the present day, and the involvement of the Polymers Division at NISTâwhich brought in industrial consortia made up of groups such as Sematech and Exxon that use small angle scattering, neutron reflectivity, and powder diffraction, and which, in partnership with General Motors, has used the Neutron Imaging Facility for imaging hydrogenous matter in large componentsâhelp the NCNR to fulfill its role of being a resource for industry. Thus, over the past decade (and longer), the NCNR has amply carried out its role as a scientific and technical resource for U.S. industry and the U.S. scientific community. In this context, gauging the scientific impact of the NCNR facility by comparing the citations to published scientific work done at the NCNR to those of other facilities would be one means to quantify the role of the facility on the world stage. The management philosophy, scientific tradition, and user satisfaction continue to be a focus of the facility. Personnel development and strategic promotion from within the NCNR have enabled this culture to continue. It is also gratifying to see that a respected retired NCNR director is still actively involved in the technical design of the new cold source and that several of the excellent and experienced retired scientists at the NCNR still take part in the scientific life and activities at the center. The plans for the upgrade appear to be well thought out and are being implemented satisfactorily. The designs for new instruments such as the very small angle neutron scattering (vSANS) spectrometer, the chromatic analysis neutron diffractometer or reflectometer (CANDoR), and the new materials diffractometer are imaginative and sound, and it is hoped that the required increase in staffing will not be disrupted by the uncertain fiscal plans of the U.S. government. The planned 10.5-month shutdown of the NCNR and decrease of neutron- scattering capabilities in the United States will adversely affect the neutron-scattering community, particularly university users whose research grants and studentsâ dissertations depend on current programs at the NCNR. It is hoped that NIST management and scientists will help facilitate for their current users alternative arrangements at the HFIR, LANSCE, and SNS. After the NCNR restarts with its suite of new instrumentsâit is hoped, as scheduled in September 2012âit is expected that the NCNR will continue to be one of the worldâs leading neutron facilities and will provide to the U.S. neutron community a resource comparable to the SNS. The maintaining of direct control of the Expansion Project and restart by the Director of the NCNR should enable rapid response to and mitigation of potential challenges for a timely restart. COMPARISON OF THE CENTER WITH OTHER USER FACILITIES The comparison between reactor sources and continuous and pulsed spallation sources is technically complicated by different power and neutron flux issues, since continuous and pulsed flux optimize different experiments. Utilization metrics including âusersâ are complicated by non-uniform definitions throughout the neutron community and therefore are excluded from the comparison of the NCNR and other user facilities. Similarly, oversubscription is not compared because user-requested time is not under 8
facility control. (Oversubscription is the number of days requested by users divided by the total number of days available.) The NCNR oversubscription rates by beam line are in a healthy range, averaging 2.2 over the facility, indicative of a robust and vibrant user community. To provide a means to evaluate the NCNR relative to other comparable user facilities and to allow for a straightforward and direct comparison, the average number of beam days that a user team requires in order to develop a publication was considered here. In most cases, a 2010 figure, if available, is reported for each metric shown in Table 1. In order to provide comparable data for sources undergoing change, a consistency check was performed to determine whether the 2010 figure was representative of a 5-year average. Thus, for example, the ISIS publications in 2010 (209) were considered representative in spite of the low 2009 (108) figure, which may have been depressed by the outage that occurred in order to bring up the second-target station; 2010 SNS and HFIR metrics were also estimated. When publication lists were available, conference proceedings were removed from counts; otherwise, publications numbers from the facilities were used directly. The definition of âhigh-impact publicationsâ as specified by the respective facilities was accepted; otherwise the âVettier Listâ was usedânamely, Nature, Science, Proceedings of the National Academy of Sciences (PNAS), Physical Review Letters (PRL), Physical Review E (PRE), Physical Review B (PRB), Journal of Molecular Biology (JMB), and Journal of the American Chemical Society (JACS). (The high-impact fraction was found to be consistent with a 2004 report by Christian Vettier for 19 neutron facilities.4) On the international scene, the clearest point of comparison is with the Institut Laue-Langevin, a reactor source of comparable power and flux to that of the NCNR. ILL is the consensus gold standard for neutron-scattering and neutron science user programs. With n = 47 instruments operating and d = 200 days of operation per year, ILL produces over p = 630 (585 for its 5-year average) publications per year and claims h = 12 to 16 percent high-impact papers. The NCNR currently has 22 instruments operating about 250 days per year (~233 days, 20-year average), 325 publications per year, and approximately 11 percent high-impact papers. Productivity P = nd/p, the average beam time required to produce a refereed publication, is 18 instrument days for NCNR, comparable to 14 instrument days at ILL. The productivity P depends on source, instrument, and user service factors. The ILL is at or near the top in budget and staffing for reactor sources. In 2010, the overall ILL staffing of 489, which includes an in-house theory group, is supported by a facility budget of 88.5 million euros, or $124 million. By comparison, the NCNR fields 134 core full-time-equivalent (FTE) staff members with a budget of $46 million; the larger NCNR staffing is 260 FTEs (including staff deployed from other NIST laboratories). 4 See Robert M. Briber, Henry Glyde (Chair), and Sunil K. Sinha, Access to Major International X-Ray and Neutron Scattering Facilities, Committee on International Scientific Affairs of the American Physical Society, April 30, 2009. Available at http://www.aps.org/programs/international/resources/upload/Facilities_Access_All_2009.pdf. Accessed August 15, 2011. 9
TABLE 1 Comparison of the NCNR with Other Representative Neutron Facilities ISIS TS1 ISIS +muons Total ILL NCNR HFIR ANSTO Lujan SNS ISIS TS2 n 7.5a 7.5a instruments 45 22 9 11 28 13 41 d days 200 267 168 340 125 177 201 179 194 p papers 66b 53b 630 325 89 109 209 50 259 2010 h % high 12% 11% 45% 11% 12% 45% 11% â â impact c c nd/p 14.3 17.9 18.9 34.4 12.6 25.0 26.9 46.5 30.7 Type reactor reactor reactor reactor spallation spallation spallation spallation spallation MW 60 20 85 20 0.1 1.0 0.3 0.1 0.4 NOTES: ILL, Institut Laue-Langevin; NCNR, NIST Center for Neutron Research; HFIR, High Flux Isotope Reactor at the Oak Ridge National Laboratory; ANSTO, Australian Nuclear Science and Technology Organisation; Lujan, Lujan Neutron Scattering Center at the Los Alamos Neutron Science Center (LANSCE); SNS, Spallation Neutron Source at the Oak Ridge National Laboratory; ISIS TS1 + muons, ISIS Spallation Neutron Source in England; ISIS TS2, ISIS Spallation Neutron Source in England; n, number of instruments; d, days of operation per year; p, number of publications in 2010; h, percentage of high-impact publications; nd/p, measure of facility output = number of instruments x number of days Ã· number of papers; type, type of neutron source; MW, megawatts. SOURCES: ï· ILL: ILL Annual Report, Available at http://www.ill.eu/fileadmin/users_files/Annual_Report/AR- 10/index.htm. Accessed June 30, 2011. ï· NCNR: National Institute of Standards and Technology, The NIST Center for Neutron Research: 2010 Accomplishments and Opportunities, NIST Special Publication 1110, December 2010. Available at http://www.ncnr.nist.gov/AnnualReport/FY2010/AR_2010_large.pdf. Accessed June 30, 2011. ï· HFIR and SNS: Allen Ekkebus, Oak Ridge National Laboratory; and Oak Ridge National Laboratory, ORNL Neutron Sciences, Neutron Review, ORNL/TM-2011/88, April 2011. Available at http://neutrons.ornl.gov/media/pubs/pdf/2010neutronreview.pdf. Accessed June 30, 2011. ï· ANSTO: ANSTO Annual Report 2009-2010, September 2011. Available at http://www.ansto.gov.au/__data/assets/pdf_file/0006/48912/AR_2010_online.pdf. Accessed June 30, 2011. ï· Lujan: for LANSCE, 2010 publications were obtained from ISI Web and Google Scholar. ï· ISIS: ISIS 2010, September 2010. Available at http://www.isis.stfc.ac.uk/about-isis/annual-report/2010/isis-annual-review-201011462.pdf. Accessed June 30, 2011. a Instruments available to general users: ï· SNS: 7.5 available throughout 2010 (8 instruments fully available in general user call for one cycle and 7 for the other);12 instruments on the floor ï· HFIR: 7.5 available throughout 2010 (8 instruments fully available in general user call for one cycle and 7 for the other); 9 instruments on the floor b Papers are only those involving research performed on or describing SNS or HFIR instruments. Publications involving all HFIR and SNS resources, including staff using other techniques and facilities and irradiation and accelerator activities, number 156 for HFIR and 250 for SNS. c Publications in 2010 result from experiments performed in 2008 and 2009 while the SNS and HFIR were constructing and commissioning many new instruments and ramping beam days. Therefore, the number of instrument days per publication metric, ând/p,â is an overestimate using the 2010 data. 10
A straightforward measure of user service is the level of beam-line staffing. The NCNR fields approximately 5 FTEs per instrument; ILL claims to field 7 FTEs.5 The NCNR is competitive with the best facilities in the world in user support. Thus, the NCNR program is currently about 50 percent of ILL in size and scope from instruments to staff. In this context, the NCNR productivity metric is excellent. 5 Colin Carlisle, Director of the ESS Scandinavia Secretariat Lund, personal communication to the panel, March 23, 2011. 11