- Email: [email protected]
PROGRESS at the ISIS Facility
ARTICLE IN PRESS
Physica B 385–386 (2006) 728–731 www.elsevier.com/locate/physb
PROGRESS at the ISIS Facility Andrew Taylor CCLRC, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 OQX, UK
Abstract Activity at the ISIS Facility, currently the world’s most successful pulsed-neutron and muon source, is described and plans for its ongoing development given. In particular, progress on the ISIS Second Target Station and its evolving instrument suite will be outlined. r 2006 Published by Elsevier B.V. Keywords: Intense; Pulsed; Neutron source
1. Introduction ISIS is the world’s most successful pulsed-neutron and muon source. Over the past twenty years since first neutrons were produced, the facility has developed into a major force in condensed matter research and attracted substantial international investment. The facility supports an international community of some 2000 scientists who use neutrons and muons for studies across a diverse range of science areas including physics, chemistry, materials science, earth science, engineering and biology Fig. 1. The variety and quality of science performed is reflected in the 1000 proposals received annually for beamtime on the 22 ISIS instruments, together with the 450 publications that result each year from ISIS investigations. ISIS’ ability to produce world-class science is a reflection not only on the quality of the instrument suite, but on the performance of the source itself—an impressive reliability of 91% underpins the science programme. The facility’s history of source and science successes continues to be built on through the rollout of new instruments, the development of new accelerator capacity and, in the now near-future, the provision of a Second Target Station introducing new science capabilities. 2. World-class science–some recent ISIS highlights Last year ISIS celebrated its 20th anniversary. Over these past two decades, the facility has seen the areas of science Tel.: +44 1235 446681; fax: +44 1235 445383.
E-mail address: [email protected]. 0921-4526/$ - see front matter r 2006 Published by Elsevier B.V. doi:10.1016/j.physb.2006.06.042
in which neutron scattering is making significant impact grow and diversify, so that drug design, energy storage, quantum devices and materials processing lie alongside more traditional areas such as magnetism or phonon studies. We present here a few examples of recent ISIS science highlights. The application of neutron diffraction to archaeometry is a novel but growing area. It offers the ability for nondestructive exploration of archaeological objects for reconstructing ancient manufacturing techniques and authenticity investigations. Recent ISIS work has included studies of a 2700-year old Greek helmet, where neutron scattering has been employed to determine the authenticity of the helmet’s nose guard. Microstructural composition and phase information from 16th century Austrian coins has also exposed imposters from genuine articles, and studies of prehistoric copper axes from Italy and Switzerland have enabled systematic investigations of Alpine copper metallurgy. Biomolecular science is a growth area which will be a feature of ISIS Second Target Station instruments. Recent ISIS highlights include studies of cell membrane catalysis. Neutron reflectometry investigations of the action of phospholipase A2 enzymes which catalyse the hydrolysis of phospholipids have enhanced our understanding of enzyme activity and specificity (Fig. 2). Small-angle neutron scattering (SANS) measurements have shed light on the configuration of complexes responsible for rearranging DNA sequences. SANS has also revealed detailed structural information on polymer systems relevant to drug delivery and personal-care products, and enables molecular
ARTICLE IN PRESS A. Taylor / Physica B 385–386 (2006) 728–731
729
Fig. 1. The ISIS Neutron Instrument Suite.
Fig. 2. A model for the interaction of porcine pancreatic phospholipase A2 with a typical bilayer membrane phospholipid produced from reflectometry data.
orientation within complex fluids to be studied during industrially relevant flow processes. ISIS neutron studies have shown unusual interfacial absorption behaviour of ‘Gemini’ surfactants with potential applications such as detergents and fabric softeners. And studies of lung surfactant proteins have shed light on the mechanisms by which they operate and enabled models of their interfacial behaviour to be developed.
ISIS continues to produce outstanding science in the areas of magnetism and superconductivity. Back-to-back Nature articles (JM Tranquada et al., and SM Hayden et al., Nature 429 (2004)) reported measurements of the magnetic excitation spectra of Y- and La-based copper oxide superconductors. The appearance of common spectral features in these materials may point to a universal description of the mechanisms underlying high-Tc
ARTICLE IN PRESS 730
A. Taylor / Physica B 385–386 (2006) 728–731
behaviour. Experimental exploration of model magnetic systems provides a basis for understanding more complex materials in which magnetism plays an important role, such as colossal magnetoresistive oxides or high-temperature superconductors. Examples include MAPS studies to high excitation energies of spinons in the 1D, antiferromagnetic S ¼ 1/2 system SrCuO2, where charge and magnetic excitations have similar energies. ISIS neutron diffraction has enabled new insights into multi-ferroics— materials exhibiting coupled magnetic and electrical ordering. The part played by magnetic frustration is key to understanding the links between magnetism and ferroelectricity in multiferroic TbMn2O5 and both neutron and muon studies at ISIS have provided details of the complex magnetic phase diagram of cobaltate compounds which show unusual superconductivity when hydrated. The recently constructed ENGIN-X instrument is providing new opportunities for the use of neutrons by the engineering community. Now equipped to produce a 3D computer representation of a sample for the planning and execution of measurements, it allows investigation of internal stresses in complex, fabricated components that are difficult to obtain using small, laboratory-sized representative samples. Stress mapping in Airbus A380 wing components and studies of stress distributions around friction welds in nickel-based superalloys relevant to the car industry are recent examples, together with in situ investigation of stresses produced by electro-discharge machining. ISIS studies of technologically relevant materials are many and varied—doping mechanisms in optoelectronic semiconductors, the characteristics of nano-scale magnetic and superconducting systems, reorientational properties of nematic liquid crystals used in displays, defect structures in ion battery anode materials, hydrogen storage in Nb-catalysed, nanostructured Mg and the structure of piezoelectric materials used as ultrasonic transducers in medical applications—all show the depth, breadth and quality of ISIS science. 3. The ISIS development strategy The ongoing demands of the ISIS science programme and the opportunity to use neutron scattering and muon spectroscopy in new science areas lead naturally to facility developments. The overall ISIS development strategy falls within the recommendations of the OECD Megascience Forum, which advocated maximising the utilisation and potential of current front-rank neutron sources (ILL and ISIS), together with timely development of next generation sources. Current opportunities for expansion and development of ISIS exist through accelerator upgrades, instrument developments and the provision of the Second Target Station. With regard to the accelerator, its recent revitalisation has included replacement of the 1960s Cockcroft–Walton ion source accelerator with a new, higher performance radiofrequency quadrupole device. This, together with insertion
of four new accelerating cavities into the ISIS synchrotron, will enable the proton beam current to be increased by 50% over the coming year. An ongoing accelerator obsolescence programme includes synchrotron extraction straight and kicker refurbishment, together with component replacement in the linac and extracted proton beam, improving source reliability and ensuring many future years of running. Instrument developments also continue apace. Installation of MERLIN, a high count rate, medium-resolution, chopper spectrometer with a very large detector solid angle, will be completed this year, providing new opportunities for single-crystal studies and advanced sample environments. The e-VERDI project is developing lowangle scattering capabilities for the VESUVIO instrument so that low momentum transfers and high energy transfers can be accessed. And, most recently, funding has been secured for a new, high-field, high-rate muon spectrometer to open up new science areas for the muon technique, together with replacement of guides on the high-resolution powder diffractometer HRPD. 4. The Second Target Station The Second Target station has been designed to provide new neutron scattering facilities to meet future scientific needs in the key (growth) areas of soft matter, biomaterials, advanced materials, and nano-materials. This includes complex multi-phase or multi-component materials, will require difficult or complex sample environments, will measure kinetic processes, perform parametric studies and will have sufficient intensity for small samples. The scientific requirements imply need for significantly enhanced cold-neutron flux (compared to the existing target station), broad spectral range and high resolution. The Second Target Station provides this with low frequency (10 Hz) to give a 100 ms frame and hence wide dynamic range. The relatively low proton beam power (48 kW) enables a highly efficient target, moderator and reflector assembly to be built, giving high long-wavelength flux. A schematic diagram of the ISIS Facility, with the second Target Station is shown in Fig. 3. The scope of the project includes the new proton beam line, target station and associated buildings and shielding as illustrated in Fig. 4. Seven new neutron-scattering instruments are funded. The project completion is defined as the release of these seven instruments to the Facility Access Panels who review proposals for experiments and allocate beam time. The approved cost of the project is £145 M with £105 M for the core project of buildings, proton beam and target station and a further £40 M for the first seven instruments. First protons are scheduled to be delivered in June 2007 with the instrument commissioning beginning later that year. The seven instruments will be fully scheduled by November 2008.
ARTICLE IN PRESS A. Taylor / Physica B 385–386 (2006) 728–731
731
Fig. 3. Schematic layout of ISIS with the Second Target Station.
5. The future
Fig. 4. The development of the Second Target Station building at the ISIS Facility.
Beyond the Second Target Station, ISIS continues to look to the future and the potential for further developments. In addition to enhanced neutron scattering and muon spectroscopy facilities, there are synergies with the requirements of future neutrino facilities. A staged upgrade path for the ISIS can be envisaged. Addition of a 3.3 GeV synchrotron, fed from the existing accelerator, would enable ISIS to progress to a 1 MW source. Powers beyond this, to 5 MW or higher, may be possible through further accelerator additions. ISIS continues to produce exciting, high-quality science; the addition of a Second Target Station, and possible developments beyond that, will ensure world-class scientific output for many years to come.
Physica B 385–386 (2006) 728–731 www.elsevier.com/locate/physb
PROGRESS at the ISIS Facility Andrew Taylor CCLRC, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 OQX, UK
Abstract Activity at the ISIS Facility, currently the world’s most successful pulsed-neutron and muon source, is described and plans for its ongoing development given. In particular, progress on the ISIS Second Target Station and its evolving instrument suite will be outlined. r 2006 Published by Elsevier B.V. Keywords: Intense; Pulsed; Neutron source
1. Introduction ISIS is the world’s most successful pulsed-neutron and muon source. Over the past twenty years since first neutrons were produced, the facility has developed into a major force in condensed matter research and attracted substantial international investment. The facility supports an international community of some 2000 scientists who use neutrons and muons for studies across a diverse range of science areas including physics, chemistry, materials science, earth science, engineering and biology Fig. 1. The variety and quality of science performed is reflected in the 1000 proposals received annually for beamtime on the 22 ISIS instruments, together with the 450 publications that result each year from ISIS investigations. ISIS’ ability to produce world-class science is a reflection not only on the quality of the instrument suite, but on the performance of the source itself—an impressive reliability of 91% underpins the science programme. The facility’s history of source and science successes continues to be built on through the rollout of new instruments, the development of new accelerator capacity and, in the now near-future, the provision of a Second Target Station introducing new science capabilities. 2. World-class science–some recent ISIS highlights Last year ISIS celebrated its 20th anniversary. Over these past two decades, the facility has seen the areas of science Tel.: +44 1235 446681; fax: +44 1235 445383.
E-mail address: [email protected]. 0921-4526/$ - see front matter r 2006 Published by Elsevier B.V. doi:10.1016/j.physb.2006.06.042
in which neutron scattering is making significant impact grow and diversify, so that drug design, energy storage, quantum devices and materials processing lie alongside more traditional areas such as magnetism or phonon studies. We present here a few examples of recent ISIS science highlights. The application of neutron diffraction to archaeometry is a novel but growing area. It offers the ability for nondestructive exploration of archaeological objects for reconstructing ancient manufacturing techniques and authenticity investigations. Recent ISIS work has included studies of a 2700-year old Greek helmet, where neutron scattering has been employed to determine the authenticity of the helmet’s nose guard. Microstructural composition and phase information from 16th century Austrian coins has also exposed imposters from genuine articles, and studies of prehistoric copper axes from Italy and Switzerland have enabled systematic investigations of Alpine copper metallurgy. Biomolecular science is a growth area which will be a feature of ISIS Second Target Station instruments. Recent ISIS highlights include studies of cell membrane catalysis. Neutron reflectometry investigations of the action of phospholipase A2 enzymes which catalyse the hydrolysis of phospholipids have enhanced our understanding of enzyme activity and specificity (Fig. 2). Small-angle neutron scattering (SANS) measurements have shed light on the configuration of complexes responsible for rearranging DNA sequences. SANS has also revealed detailed structural information on polymer systems relevant to drug delivery and personal-care products, and enables molecular
ARTICLE IN PRESS A. Taylor / Physica B 385–386 (2006) 728–731
729
Fig. 1. The ISIS Neutron Instrument Suite.
Fig. 2. A model for the interaction of porcine pancreatic phospholipase A2 with a typical bilayer membrane phospholipid produced from reflectometry data.
orientation within complex fluids to be studied during industrially relevant flow processes. ISIS neutron studies have shown unusual interfacial absorption behaviour of ‘Gemini’ surfactants with potential applications such as detergents and fabric softeners. And studies of lung surfactant proteins have shed light on the mechanisms by which they operate and enabled models of their interfacial behaviour to be developed.
ISIS continues to produce outstanding science in the areas of magnetism and superconductivity. Back-to-back Nature articles (JM Tranquada et al., and SM Hayden et al., Nature 429 (2004)) reported measurements of the magnetic excitation spectra of Y- and La-based copper oxide superconductors. The appearance of common spectral features in these materials may point to a universal description of the mechanisms underlying high-Tc
ARTICLE IN PRESS 730
A. Taylor / Physica B 385–386 (2006) 728–731
behaviour. Experimental exploration of model magnetic systems provides a basis for understanding more complex materials in which magnetism plays an important role, such as colossal magnetoresistive oxides or high-temperature superconductors. Examples include MAPS studies to high excitation energies of spinons in the 1D, antiferromagnetic S ¼ 1/2 system SrCuO2, where charge and magnetic excitations have similar energies. ISIS neutron diffraction has enabled new insights into multi-ferroics— materials exhibiting coupled magnetic and electrical ordering. The part played by magnetic frustration is key to understanding the links between magnetism and ferroelectricity in multiferroic TbMn2O5 and both neutron and muon studies at ISIS have provided details of the complex magnetic phase diagram of cobaltate compounds which show unusual superconductivity when hydrated. The recently constructed ENGIN-X instrument is providing new opportunities for the use of neutrons by the engineering community. Now equipped to produce a 3D computer representation of a sample for the planning and execution of measurements, it allows investigation of internal stresses in complex, fabricated components that are difficult to obtain using small, laboratory-sized representative samples. Stress mapping in Airbus A380 wing components and studies of stress distributions around friction welds in nickel-based superalloys relevant to the car industry are recent examples, together with in situ investigation of stresses produced by electro-discharge machining. ISIS studies of technologically relevant materials are many and varied—doping mechanisms in optoelectronic semiconductors, the characteristics of nano-scale magnetic and superconducting systems, reorientational properties of nematic liquid crystals used in displays, defect structures in ion battery anode materials, hydrogen storage in Nb-catalysed, nanostructured Mg and the structure of piezoelectric materials used as ultrasonic transducers in medical applications—all show the depth, breadth and quality of ISIS science. 3. The ISIS development strategy The ongoing demands of the ISIS science programme and the opportunity to use neutron scattering and muon spectroscopy in new science areas lead naturally to facility developments. The overall ISIS development strategy falls within the recommendations of the OECD Megascience Forum, which advocated maximising the utilisation and potential of current front-rank neutron sources (ILL and ISIS), together with timely development of next generation sources. Current opportunities for expansion and development of ISIS exist through accelerator upgrades, instrument developments and the provision of the Second Target Station. With regard to the accelerator, its recent revitalisation has included replacement of the 1960s Cockcroft–Walton ion source accelerator with a new, higher performance radiofrequency quadrupole device. This, together with insertion
of four new accelerating cavities into the ISIS synchrotron, will enable the proton beam current to be increased by 50% over the coming year. An ongoing accelerator obsolescence programme includes synchrotron extraction straight and kicker refurbishment, together with component replacement in the linac and extracted proton beam, improving source reliability and ensuring many future years of running. Instrument developments also continue apace. Installation of MERLIN, a high count rate, medium-resolution, chopper spectrometer with a very large detector solid angle, will be completed this year, providing new opportunities for single-crystal studies and advanced sample environments. The e-VERDI project is developing lowangle scattering capabilities for the VESUVIO instrument so that low momentum transfers and high energy transfers can be accessed. And, most recently, funding has been secured for a new, high-field, high-rate muon spectrometer to open up new science areas for the muon technique, together with replacement of guides on the high-resolution powder diffractometer HRPD. 4. The Second Target Station The Second Target station has been designed to provide new neutron scattering facilities to meet future scientific needs in the key (growth) areas of soft matter, biomaterials, advanced materials, and nano-materials. This includes complex multi-phase or multi-component materials, will require difficult or complex sample environments, will measure kinetic processes, perform parametric studies and will have sufficient intensity for small samples. The scientific requirements imply need for significantly enhanced cold-neutron flux (compared to the existing target station), broad spectral range and high resolution. The Second Target Station provides this with low frequency (10 Hz) to give a 100 ms frame and hence wide dynamic range. The relatively low proton beam power (48 kW) enables a highly efficient target, moderator and reflector assembly to be built, giving high long-wavelength flux. A schematic diagram of the ISIS Facility, with the second Target Station is shown in Fig. 3. The scope of the project includes the new proton beam line, target station and associated buildings and shielding as illustrated in Fig. 4. Seven new neutron-scattering instruments are funded. The project completion is defined as the release of these seven instruments to the Facility Access Panels who review proposals for experiments and allocate beam time. The approved cost of the project is £145 M with £105 M for the core project of buildings, proton beam and target station and a further £40 M for the first seven instruments. First protons are scheduled to be delivered in June 2007 with the instrument commissioning beginning later that year. The seven instruments will be fully scheduled by November 2008.
ARTICLE IN PRESS A. Taylor / Physica B 385–386 (2006) 728–731
731
Fig. 3. Schematic layout of ISIS with the Second Target Station.
5. The future
Fig. 4. The development of the Second Target Station building at the ISIS Facility.
Beyond the Second Target Station, ISIS continues to look to the future and the potential for further developments. In addition to enhanced neutron scattering and muon spectroscopy facilities, there are synergies with the requirements of future neutrino facilities. A staged upgrade path for the ISIS can be envisaged. Addition of a 3.3 GeV synchrotron, fed from the existing accelerator, would enable ISIS to progress to a 1 MW source. Powers beyond this, to 5 MW or higher, may be possible through further accelerator additions. ISIS continues to produce exciting, high-quality science; the addition of a Second Target Station, and possible developments beyond that, will ensure world-class scientific output for many years to come.