Development of High Intensity Cold Neutron Spectrometer with Multichannel Analyzer

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This award from the Major Research Instrumentation program to Johns Hopkins University supports the development of a Multi Analyzer Crystal Spectrometer (MACS) for cold neutron spectroscopy. MACS will have two orders of magnitude greater sensitivity than current instrumentation. Located at the NIST cold neutron source, the instrument uses focusing Bragg optics to produce the most intense cold neutron beam worldwide (f108 n/cm2/s for DEi=0.2 meV). The detection system will energy-analyze neutrons scattered into a solid angle more than an order of magnitude greater than conventional instrumentation. The goal of the MACS project is greater insight into nano-scale dynamic phenomena in materials science. It will expand the scope for inelastic neutron scattering from a powerful specialized technique to a versatile probe of dynamic correlations in a wide range of condensed matter. Research enabled by MACS includes direct measurements of interactions in magnetic thin films, determination of spin density wave structure in organic metals, elucidation of spin and charge polarons in oxides, studies of dynamic correlations at pressure and field driven quantum phase transitions, determination of order parameters in weak broken symmetry phases, and studies of impurity generated composite spin. With a different "foot print" in Q-E phase space, MACS will complement the advanced pulsed neutron instrumentation now being developed for the Spallation Neutron Source. The project will provide undergraduate, graduate, and postdoctoral education to produce scientists that are knowledgeable about cutting-edge neutron scattering instrumentation and its use in materials research. Inelastic neutron scattering is a unique probe of nano-scale dynamic phenomena in solids. The experiments are crucial for determining the interactions and understanding the cooperative phenomena that govern the solid state. Unfortunately, current instrumentation limits applicability to cases where large crystalline samples are available. This award from the Major Research Instrumentation program to Johns Hopkins University supports the development of a Multi Analyzer Crystal Spectrometer (MACS) for neutron scattering at the NIST Center for Neutron Research. Through its intense incident beam and its multiplexing detection system, MACS will transform inelastic neutron scattering from a powerful, specialized technique, to a versatile probe of nano-scale dynamics in solids. Research enabled by MACS, includes direct measurements of interactions in magnetic thin films, determination of spin density wave structure in organic metals, elucidation of spin and charge polarons in oxides, and analysis of impurity generated composite spin. Graduate and undergraduate students will be involved, and a post-doc will join for commissioning. The project thus educates scientists who are knowledgeable about cutting-edge neutron scattering instrumentation and its use in materials science. With a different data acquisition protocol, MACS will be complementary to instrumentation now being developed for the Spallation Neutron Source. The capability to probe excitations over a wide range of energies at the SNS and then zoom in using MACS will help scientists develop new materials for the twenty first century.