Facilities
Large-scale facilities

IN13

General informations

Location
Institut Laue Langevin (ILL), Grenoble, France
Main techniques and methods
Incoherent Elastic and Quasi-elastic Neutron Spectroscopy
Key instumentation
- high energy resolution backscattering spectrometer CRG-IN13 at ILL

IN13 is a unique spectrometer at a high flux reactor devoted to the study of the internal macromolecular dynamics

IN13 is currently a unique spectrometer at a high flux reactor to permit the exploration of the 100 picosecond time scale window with a scattering vector modulus Q going up to ~5 Å-1. The large Q range attainable is very useful to discriminate between different motion geometries in the sample. In fact, unlike back-scattering spectrometers with energy resolution of ~1μeV, the lower resolution on IN13 makes it relatively insensitive to global diffusion, allowing internal motions to dominate the data. It makes it also relatively insensitive to scattering by water diffusion.

Technical description

IN13 is a backscattering spectrometer working with thermal neutrons with wavelength 2.23 Ǻ corresponding to energy of 16.45 meV. The variation of the incident neutron energy is obtained by adjusting the d-spacing of the monochromator by heating/cooling it. The energy resolution is of the order of 8 μeV and the energy window is ± 150 μeV, corresponding to a time scale ranging from 10- 12 s to 10-10 s. The neutrons leaving the guides are selected in energy by a CaF2 monochromator and then reflected by a pyrolytic graphite deflector to finally reach the sample through a chopper device. The beam dimension at the sample position is defined by a double-slit system. The beam scattered from the sample is reflected in almost perfect backscattering geometry by CaF2 analysers mounted on spherically/circularly curved Al plates, to be finally collected by 35 He3 gas counter detectors and a position-sensitive detector for the medium-large and small scattering angles, respectively. The background noise is minimized through the insertion of a conic collimator covered with gadolinium paint. The instrument fills the energy gap between IN10 or IN16 and IN5 at ILL, MIBEMOL at the LLB or IRIS at the Rutherford-Appleton laboratory (RAL) in United-Kingdom. In addition the value of the incident energy gives the availability of high momentum transfers (Q < 4.9 Å-1, extendable to 5.5 Å-1), much larger than obtainable with the above-mentioned spectrometers.

Development of new methods, instrumentation, software

In the framework of the ILL Endurance project, the instrument will benefit of a substantial upgrade, which includes mainly two major issues:

  • The present nickel coated guide H24 will be replaced by supermirrors providing an increasing in neutron intensity by a factor of ~ 2-3, without affecting the energy resolution of the instrument.
  • A new monochromator will be installed. The idea consists in applying a temperature gradient to the monochromator crystals to let vary the d-spacing due to thermal expansion. The flux increment would   then arise from the apparent increase in mosaicity (by a factor of ~4-5) at no cost of energy resolution.

Research Activity

Applications are found in biology, medical science, chemistry, cultural heritage, etc. Among them:

  • Physics: order-disorder phase transition in imogolite nanotubes, energy storage, etc
  • Biology: cellular response to external signals and extreme conditions (high P, high T, pH, etc.), studies of whole cells in vivo, etc.
  • Agricultural science: mechanisms of seed germination to perpetuate plants.
  • Biomedicine: properties of water diffusion in cerebral tissues with important implications for a deeper understanding of cerebral pathologies.
  • Chemistry: biopolymer hydrogels and their pharmaceutical and medical applications.

Main collaborations

National:

  • Milan University, Milano
  • Pisa University, Pisa
  • Palermo University, Palermo
  • Elettra - Sincrotrone Trieste, Trieste
  • Perugia University, Perugia

International:

  • Strasbourg University, France 
  • Niels Bohr Institute, Copenhagen University, Denmark
  • Santa Cruz University, Santa Cruz, USA
  • Institut de Biologie Structural, Grenoble, France
  • Paris 6 University, Paris, France  
  • Université Grenoble Alpes, Grenoble, France
  • AgroSup Dijon, Dijon, France
  • Medical University of Graz, Graz, Austria
  • ISIS Facility, Rutherford Appleton Laboratory, Chilton, OXON, UK
  • Weizmann Institute of Science, Rehovot, Israël
  • Technische Universität Dortmund, Dortmund, Germany
  • Institut Laue Langevin, Grenoble, France