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6 Center for High Resolution Neutron Scattering Program The Center for High Resolution Neutron Scattering Program has done an excellent job of meeting and exceeding its objectives. The CHRNS is a National Science Foundation program started in 1990 that currently supports the operation of six spectrometers and associated personnel at the NCNR. Covering roughly 30 percent of the NCNR beam lines, the CHRNS is the heart of the NCNR User Program and sets the standard for other U.S. facilities with respect to productivity. Each year, the CHRNS supports about 500 users, many of them graduate students, and yields about 100 publications. About half of the high-impact publications of the NCNR are from the CHRNS, and more than 25 Ph.D. theses benefited from research conducted on CHRNS instruments. The suite of CHRNS instruments covers a broad length scale and energy range for dynamical studies. The reliability of the instruments is excellent, consistently over 98 percent. The oversubscription rate of the instruments is 2.2, attesting to the strong user base. Five of the six instruments are state of the art, including the following: the BT5-USANS, a unique, ultra- small-angle neutron scattering instrument; the NG2-HFBS, a state-of-the-art inelastic high flux backscattering spectrometer (HFBS) with the highest count rate and smallest energy resolution in the world; the NG3-30 m SANS, a workhorse instrument and the only polarized SANS in the United States; the NG5-Spin-Echo spectrometer, which will be upgraded with a guide, polarizer, and improved magnetic-field compensation, making it competitive with the new instrument under construction at the Spallation Neutron Source; and the NG5-SPINS, which has the highest magnetic field on a spin-polarized inelastic neutron scattering instrument in the United States. The NG-4 DCS (disk chopper spectrometer) has been a workhorse instrument for the CHRNS, but it will be less competitive with the commissioning of the Cold Neutron Chopper Spectrometer (CNCS) at the SNS. The timely replacement of the DCS with the Multi Axis Crystal Spectrometer (MACS) will add an internationally competitive instrument, 100 times faster than the DCS and 10 times faster than the CNCS at a constant energy plane, with unique sample environment capabilities 11 T magnet and dilution refrigeration to 0.03 K. The CHRNS suite of instruments will, therefore, continue to offer internationally competitive instruments for the broad materials science community. A key contribution of the CHRNS program is its educational impact on the neutron scattering community. Every educational program produced by the NCNR is solely supported by the CHRNS. In addition, the NSF Research Experiences for Undergraduates and the Summer Undergraduate Research Fellowship programs at NIST are leveraged through the CHRNS to provide undergraduates with summer research opportunities to learn about and use neutrons in the studentsâ research activities. The chair of the NUG commented to the panel that the CHRNS summer schools are oversubscribed by a factor of three. To address this great need for additional educational opportunities, the inelastic and small-angle themed summer schools should be offered every year instead of every other year. This doubling of summer school slots would enable more students to be served in a timely fashion. Another key outreach activity is the advertisement of neutron scattering at scientific conferences to attract new users. Talks by NCNR personnel offer an effective bridge from researchers investigating the type of scientific questions and problems that neutron scattering can 17
address to researchers in a broad range of fields who currently do not use neutron scattering. A key aspect of interfacing with new users, beyond providing assistance during the measurements, is following up to ensure that no questions remain and that the data are fully analyzed after researchers return to their home institutions. Such educational outreach is as important as providing the summer school and is a great benefit for novice users of the CHRNS instruments. The development of analysis software by CHRNS-affiliated personnel has also been substantial. Inelastic scattering software (Data Analysis and Visualization Environment, or DAVE) and IGOR-based SANS analysis software continue to be developed and maintained with the support of the CHRNS. Other educational activities have included a coordinated effort to increase the visibility and use of the new USANS instrument. Over the past year, this has led to a doubling in the number of beam time request proposals. The instrument is now oversubscribed by a factor of 1.6, a number that is likely to grow in the near future. The increased workload for CHRNS personnel warrants additional support so that an expanded summer school can be offered and the excellent user program and high-impact science conducted with the CHRNS instruments can be maintained. In summary, the CHRNS partnership between the NCNR and NSF is commendable. The high-impact and prodigious scientific output from the use of the CHRNS instruments is outstanding. The cost sharing two thirds from NIST-NCNR and one third from NSF is highly effective. If CHRNS funding is not continued in subsequent years, the impact on the neutron scattering community in the United States would be extremely negative. State-of-the-art and internationally competitive instruments would have to be removed from the user program if there would no longer be sufficient personnel to operate and maintain the instruments. The United States already lags behind Europe by 50 percent in terms of neutron scattering instruments. The user program would be dealt a further blow if the level of support to carry out experiments, analyze data, provide software, and provide educational opportunities were greatly reduced. The continuation of the CHRNS partnership should be given strong support. 18
