alan hewat, ill diffraction group leader
TRANSCRIPT
Alan Hewat, NMUM 10-11 Jan 2002
The ILL Millennium Programme in DiffractionAlan Hewat, ILL Diffraction Group Leader
Alan Hewat, NMUM 10-11 Jan 2002
The ILL Millennium Programme in Diffraction
� New 10 year ILL contract just signed
� Millennium Programme -> ILL machines by x10 to x20
� New detector and neutron optic technology
� Infrastructure renewal – super-mirror guides, hot source
Alan Hewat, NMUM 10-11 Jan 2002
New Instruments:
� D2b – high resolution powder diffractometer with linear PSDs
� D20 – a large microstrip detector for chemical kinetics…
� D4c – a microstrip detector for liquids & amorphous materials
� D19 – an array of 2D-microstrips for protein/fibre diffraction
� VIVALDI – Laue Diffractometer with Neutron Image Plate
� Strain Scanner – for mapping strain using microstrip detectors
� D3 polarised neutron diffractometer (polarimetry & He3 filter)
The ILL Millennium Programme in Diffraction
Alan Hewat, NMUM 10-11 Jan 2002
The ILL Millennium Programme
� D2B –very high resolution, good intensity (Rietveld)Current EPSRC proposal for Super-D2B
� D20 – very high intensity, good resolution (kinetics)Microstrip detectors, high speed electronics, big focussing monochromators
(future Super-D20 proposal for a much larger PSD detector)
Alan Hewat, NMUM 10-11 Jan 2002
Super-D2B High Resolution Powder Diffractometer
Metal hydrides BaReH9
A high precision powder diffractometer – high resolution plus high flux
cf HRPD at ISIS
New metal hydrides, new phases of ice/clathrates, charge order in CMR, high Tc etc
Valence Sum V=Σi[exp(Ro-Ri)/B]
High pressure ice/clathrates
Alan Hewat, NMUM 10-11 Jan 2002
Super-D2B High Resolution Powder DiffractometerCharge order, Mixed valence, CMR materials, Magnetism…
M(Ni1) = -1.4 µµµµBM(Ni2) = 0.7 µµµµB
Combined ESRF, D1B and D2B data - Alonso J.A. et al (1999) PRL 82, 3873
Metallic Ortho. YNiO3 -> Insulating Mono. YNiO3 T < 582K Ni valence 3-δ, 3+ δ
V(Ni1) = 2.62 V(Ni2) = 3.17
Ni1 Ni2
� Double evidence for charge transfer� Magnetic superstructure and different moments on Ni-sites
� Different Ni-O distances around Ni1 and Ni2 sites mean ‘charge transfer’
� Neutrons provide both. But need:� High resolution to resolve symmetry
� High flux to see superstructure
� Small samples – again high flux
Alan Hewat, NMUM 10-11 Jan 2002
Large pseudo-2D PSD (array of 5’ collimators & linear-wire detectors)
� 2D detector allows both high efficiency & high resolution
Super-D2B High Resolution Powder DiffractometerCurrent EPSRC proposal of Paul Attfield et al. Cambridge
Alan Hewat, NMUM 10-11 Jan 2002
The 160o D20 Microstrip Arraycf GEM at Isis
25 plates of 64 electrodes are assembled to produce a 1600-wire detector covering 160o.
Alan Hewat, NMUM 10-11 Jan 2002
Explosive Reactions create New Materials
In-situ neutron powder diffraction at 0.9s time resolution. Daniel Riley, Erich Kisi et al.
“How do we create a material that has the high temperature properties of a ceramic, but is electrically conducting like a metal - Ti
3SiC
2”
Complete pattern measured every 0.9 seconds !
Alan Hewat, NMUM 10-11 Jan 2002
The ILL Millennium Programme
� Super versions of both D2B and D20 are planned (big detectors)
� Both D2B and D20 are currently 100% available
Deadlines for proposals: FAST proposals - Sunday 13 January
NORMAL proposals - End of February
On-line submission: “Visitors’ Club” http://vitraill.ill.fr/cv/
Alan Hewat, NMUM 10-11 Jan 2002
An array of Microstrip DetectorsNew D4C Liquids & Amorphous Materials Diffractometer
The new ILL hot source, to be installed soon, will result in x10 intensity
Very high efficiency & stability needed for isotope replacement method
Alan Hewat, NMUM 10-11 Jan 2002
An array of Microstrip DetectorsNew D4C Liquids & Amorphous Materials Diffractometer
Henry Fischer, Gabriel Cuello et al.
Alan Hewat, NMUM 10-11 Jan 2002
The D4c microstrip detector and isotope replacement
The conformation of water around saturated sugar solutionsP.E. Mason, G.W. Neilson, A.C. Barnes, M-L. Saboungi, and G.J. Cuello
6
The very high efficiency and stability of D4c makes the isotope replacement method with very small samples much more powerful.
A first experiment on D4c with hydrogen/deuterium replacement showed that even in 50% saturated glucose solutions, the conformation of water is not much perturbed.
Oxygen
Hydrogen
Carbon
Alan Hewat, NMUM 10-11 Jan 2002
A 2D Microstrip Detector
D9, D10, D15, D-Strain Scanner
A printed circuit on BOTH sides of the glass substrate
2D detectors are now used on all ILL single crystal diffractometers
Alan Hewat, NMUM 10-11 Jan 2002
Artists impression of the new ILL-EPSRC strain scanner behind D1A/D1B
The New ILL-EPSRC Strain Scanner
EPSRC grant of ~ 1M Pounds Sterling to Phil Withers et al. Manchester
Alan Hewat, NMUM 10-11 Jan 2002
An Array of 2D Detectors D19 Fibre & Protein Diffractometer
300x300 mm (128x128) 2D
wire or microstrip detector
Photos show the 200x200mm
prototype already tested on D19
Alan Hewat, NMUM 10-11 Jan 2002
Water in DNA sheets on D19
(a) with H2O (b) with D2O
Present 4° detector
The 15 year old D19 detector covers only a thin 2D strip
Alan Hewat, NMUM 10-11 Jan 2002
9 Independent 2D microstrip detectors
An Array of 2D Microstrip Detectors Successful EPSRC proposal of Judith Howard et al.
� 15 year old D19 detector covers only a thin 2D strip
� Replace with an array of high resolution 2D modules
� Increase efficiency x25
� Fibre DiffractionSmall protein structuresIn-situ hydration studies.
D19 Fibre & Protein Diffractometer
Alan Hewat, NMUM 10-11 Jan 2002
Neutron Image Plates & Microstrip DetectorsClive Wilkinson (Kings) & Dean Myles (EMBL)
Nature (1997) Cover showing LADI data
(LAue Diffractometer with Image plates)
Alan Hewat, NMUM 10-11 Jan 2002
� Neutron guide
� Band of neutron energies
� View reciprocal space
� In-situ laser readout
� Unique survey of P/T
� Phase T/Ns, superstruct.
Dean Myles with LADI and cryo-refrigerator on thermal guide H22
LADI Neutron Image Plate LAue Diffractometer Clive Wilkinson (Kings) & Dean Myles (EMBL)
Alan Hewat, NMUM 10-11 Jan 2002
Neutron Image Plate 5-fold symmetry of quasi-crystal
5-fold symmetry axis in ZnMgY quasi-crystal - De Boissieu et al. (1999)
T-LADI neutron image plate photo courtesy of G. McIntyre, Oct 1999
Alan Hewat, NMUM 10-11 Jan 2002
Neutron Image Plate 5-fold symmetry of quasi-crystal
Rocking the ZnMgY quasi-crystal (Dynamics) – McIntyre, Cowan (1999)
Alan Hewat, NMUM 10-11 Jan 2002
VIVALDI, A New Thermal Neutron Image PlateClive Wilkinson (Kings) & Garry McIntyre
First neutrons before Christmas !!!
� Vertical geometry with cryostat� More efficient internal IP� Faster read-out� Thermal neutron s-mirror guide
� We encourage people to come orsend students for extendedperiods to try this exciting new technique.
Alan Hewat, NMUM 10-11 Jan 2002
• vertical detector to allow extreme sample environments
• single-crystal diffraction will be as ‘easy’ and as fast as powder diffraction
Laue diffraction pattern of incommensurate La2Co
1.7
- within a day of the first neutrons: 23/11/01 !
VIVALDI – Thermal neutron image-platefor physics, chemistry and materials science