Neutron Science
Facilities
The ORNL Neutron Science Program
provides users
with access to both a
Both
facilities offer one-of-a-kind, state-of-the-art
instruments and support.
Other ORNL Resources of Interest
Research capabilities at HFIR and SNS are enhanced by the ready availability of other research facilities at ORNL. Because all of the facilities are operated by ORNL, access and training requirements are simplified. The Center for Nanophase Materials Sciences even uses the same proposal system as HFIR and SNS. An important goal for Neutron Sciences is improving integration between the facilities, making it easier for users to access the support and capabilities they need to produce the best science possible. Some of the facilities that users can benefit from while visiting ORNL:
Key Contacts for Neutron Scattering at ORNL
High Flux Isotope Reactor
|
HFIR will have 15 state-of-the-art
neutron-scattering instruments
that will be among the world's best.
(Click
for larger view.)
|
The 85-MW High Flux Isotope Reactor (HFIR) provides one of the highest steady-state neutron fluxes of any research reactor in the world. HFIR fulfills four missions: neutron scattering, isotope production, materials irradiation, and neutron activation. This web site focuses on the neutron scattering activities of the facility. The neutron scattering instruments at HFIR enable fundamental and applied research into the molecular and magnetic structures and behavior of materials, such as polymers, metals, and biological samples. HFIR has 15 instruments planned or in operation. A new cold neutron source installed during a HFIR refurbishment in 2006–2007 uses liquid hydrogen to slow the movement of neutrons, making them particularly useful for certain types of experiments. This cold source will greatly enhance the reactor’s research capabilities, particularly in the biological sciences.
In 2007, HFIR completed the most dramatic transformation in its 40-year history. During a shutdown of more than a year, the facility was refurbished and a cold neutron source and two cold source instruments were installed. The reactor was restarted in mid-May; it attained its full power of 85 MW within a couple of days, and experiments resumed within a week.
Cold Source
The cold source was tested successfully during the first few months of 2007 and demonstrated that the cold source would support safe, reliable operation of the reactor. The cold neutron beams have been measured to characterize their intensity, and the neutron spectrum from the cold moderator (without passing through the intervening neutron guides) was measured using neutron time-of-flight methods to determine both the neutron flux entering the guides and the spectral brightness of the moderator. The spectral brightness for a reactor power level of 85 MW and cold source temperature of 22.5 K was compared with the brightness predicted by an MCNP (Monte Carlo N-Particle) computer simulation before construction of the cold source. The observed peak brightness is about 6% less than the predicted brightness; however, the brightness between 3 and 10 Å (the HB-4 cold source was designed to optimize the number of neutrons in this range) is as much as a factor of two greater than predicted by the MCNP. In fact, within the error bars of the experiment, the cold source is performing as well as any other cold neutron source in the world.
Cold Source Contact: Eric Iverson, (iversoneb@ornl.gov)
Productivity and Reliability
Completion of cold source testing was followed by a highly productive period of reactor operation. From May through December, HFIR operated for 9169.6 MWd at its 85-MW full-power rating with the exception of a few hours at lower power to perform the HB-4 brightness measurements. This provided valuable neutron scattering instrument commissioning time and 1178 facility operating hours for users. During this time, 72 users performed 35 neutron scattering experiments. In addition to neutron scattering work, HFIR staff performed isotope production, neutron activation analysis, and materials irradiation experiments.
Steady-state operation of HFIR will eventually provide neutron beams for eight to ten reactor cycles per year. With regular operation, the next anticipated major shutdown—for a beryllium reflector replacement—will not be necessary until after 2020. In the future, it’s possible to install a second cold source in radial beam tube HB-2, which would provide an unparalleled flux of cold neutrons feeding instruments in a new guide hall.
An aggressive operating schedule is planned for 2008, with a tentative schedule of 140 operating days. This schedule assumes six operating cycles during the calendar year.
HFIR Operations Contact: Mike Farrar, (farrarmb@ornl.gov)
Spallation Neutron Source
|
SNS can accommodate up to 24 instruments.
(Click for details.)
|
The Spallation Neutron Source (SNS) is a recently completed accelerator-based neutron source that, when ramped up to full power, will provide the most intense pulsed neutron beams in the world for scientific and industrial research and development. At its full beam power of 1.4 MW, SNS will be eight times more powerful than the best facility now operating. This powerful scientific tool will give researchers the most detailed snapshots of the smallest samples of physical and biological materials ever possible. The diverse applications of neutron scattering research will provide opportunities for experts in practically every scientific and technical field. With the eventual SNS suite of up to 25 best-in-class instruments (located on 18 beam lines), scientists will be able to count scattered neutrons, measure their energies and the angles at which they scatter, and map their final positions. These instruments will allow measurements of greater sensitivity, higher speed, higher resolution, and in more complex sample environments than ever before.
The year 2007 was the first full year of operation for SNS. By meeting and exceeding the performance goals set for the year, SNS has become the world’s most powerful short-pulse spallation neutron source.
SNS received approval to increase beam power from 100 kW to 2 MW. On August 11, SNS set a new world record for pulsed sources by operating at 183 kW for more than one day. In September, SNS set another world record of 1.1 × 1014 protons per pulse and achieved a neutron production rate of 160 MWh, exceeding the facility goal of 117 MWh. In addition, the neutron production hour goal of 1500 hours was exceeded by reaching 2113 hours. Later, in preparation for the first neutron production run in FY 2008, a beam was run to the target for the first demonstration of 60-Hz beam operation for a shift at ~70 kW. Accelerator availability is also on track at 79% for the last run of FY 2007.
For the next year, plans are to operate for 4000 hours, reach an operating power of 750 kW, and produce neutrons for 2700 hours. In addition, machine availability is expected to increase to about 83%.
SNS Operations Contact: George Dodson, (dodsong@ornl.gov)
Center for Structural Molecular Biology
The Bio-SANS instrument at HFIR’s cold source is the cornerstone of the Center for Structural Molecular Biology (CSMB), established to support and develop user programs in the bio-sciences. CSMB is developing the facilities, data analysis, and modeling methods necessary for effective use of the Bio-SANS. It provides tools for protein expression, purification, and biophysical characterization in preparation for neutron scattering experiments. Additionally, a small-angle X-ray scattering (SAXS) instrument and light scattering instrumentation are available to users for ensuring that the highest-quality samples are measured in the Bio-SANS. CSMB has established a Bio-Deuteration Laboratory for in-vivo production of hydrogen/deuterium-labeled bio-macromolecules for research at HFIR and SNS. Hydrogen/deuterium labeling of biological samples allows selected parts of macromolecular structures to be highlighted and analyzed in situ using neutron scattering. Part of the mission of the Bio-Deuteration Lab is training researchers and students in using and applying these biological research techniques to support neutron analysis of large bio-molecular complexes. CSMB is also expanding its efforts to include the study of biomembranes by neutron reflectometry and is developing methods for data reduction and analysis of SANS and SAXS data. (Available modeling tools for small-angle scattering data.)
Computational techniques are being developed at CSMB for the study of macromolecular complexes by SANS. Combined with selective deuterium labeling, they will make it possible to develop detailed structural models that will enable the understanding of function.
CSMB Contact: Dean Myles, (mylesda@ornl.gov)
Center for Nanophase Materials Sciences
|
One of the CNMS state-of-the-art laboratories.
|
The Center for Nanophase Materials Sciences (CNMS) is a research facility for nanoscale science and technology, one in a national network of five users centers established by DOE. Housed in an 80,000-ft2 building adjacent to SNS, CNMS allows its users access to a complete suite of unique capabilities for studying nanoscale materials and assemblies. CNMS integrates nanoscale science with three other research areas:
- Neutron science using the resources of SNS and HFIR.
- Synthesis science facilitated by synthesis capabilities in macromolecular nanomaterials, catalytic nanosystems, and functional hybrid nanostructures labs and by a new Nanofabrication Research Laboratory.
- Theory, modeling, and simulation using the resources of the Nanomaterials Theory Institute and access to high-performance computing centers at the National Center for Computational Sciences housed at ORNL and the National Energy Research Supercomputing Center at Lawrence Berkeley National Laboratory.
CNMS Contact: Linda Horton, (hortonll@ornl.gov)
National Center for Computational Sciences
The National Center for Computational Sciences (NCCS) at ORNL is the Leadership Computing Facility for the United States. It is host to the Cray XT4 “Jaguar” supercomputer, the most powerful supercomputer in the world for open scientific use, which was ranked No. 2 on the Top500 list of the world’s fastest supercomputers in 2007. Jaguar’s peak performance was more than 119 trillion calculations per second (119 teraflops) at the end of 2007, and an upgrade effort was under way to upgrade it to 250 teraflops. Plans are to install a petaflops supercomputer, capable of a quadrillion calculations per second, in 2008. NCCS also is home to several smaller supercomputers.
To support its supercomputing power, NCCS has put in place high-speed fiber-optic networks to expedite data movement, a scientific visualization center that enables researchers to analyze their simulation results quickly and comprehensively, and a high-performance data archiving and retrieval system. It also has a top-flight technical and scientific computing staff to help researchers make the best use of the computing resources.
NCCS hosts scientific computing projects that have the potential to produce groundbreaking results. Allocations for large projects (i.e., those needing millions of processor-hours) are awarded through a proposal process that issues a call for proposals once yearly. Smaller allocations of time occasionally are awarded to “director’s discretion” projects.
NCCS Contact: Jim Hack, (jhack@ornl.gov)
Shared Research Equipment User Facility
The Shared Research Equipment User Facility (SHaRE) is an electron beam microcharacterization center, one of three in the United States supported by DOE. SHaRE provides access to a suite of advanced instruments and expert staff scientists for the micrometer-to-nanometer-scale characterization of materials in several focused research areas:
- Transmission and scanning electron microscopy (including aberration-corrected scanning tunneling electron microscopy and high-angle annular dark field imaging, electron energy-loss spectrometry, energy dispersive spectroscopy, and orientation imaging microscopy)
- Atom probe tomography
- X-ray photoelectron spectrometry
- Dual-beam focused ion beam and ultramicrotomy specimen preparation and support
Researchers from universities, public research institutions, and private industry can submit research proposals for review and approval to gain access to SHaRE’s characterization facilities. Proposals are accepted at any time.
SHaRE Contact: Karren More (morekl1@ornl.gov)
High Temperature Materials Laboratory
The High Temperature Materials Laboratory (HTML) helps solve materials problems that limit the efficiency and reliability of automotive systems. HTML has six user centers that are available to researchers in universities, public research institutions, and private industry. The centers are staffed by experts in the materials sciences and equipped with instruments that can characterize the structural, chemical, physical, and mechanical properties of materials at nanoscale and microscale and over a wide range of temperatures and pressures. Research capabilities offered by the HTML include:
HTML Contact: Edgar Lara-Curzio, (laracurzioe@ornl.gov) |
