CLRC news and IUCr satellite meetings
The Daresbury Laboratory is hosting an IUCr satellite meeting on the 'Production and utilisation of synchrotron radiation for structural studies of matter ' from 1st to 4th August 1999; the program for the meeting is on a later page of this newsletter; a registration form is enclosed for your convenience. Colin Carlile of the Rutherford Appleton Laboratory is organising a satellite meeting in Oxford on the 'Structure and dynamics of molecular and Ionic solids using neutrons' from 1st to 3rd August 1999. Further details of both meetings can be found on the WWW on the BCA meetings pages.
Scientific tourist information for the geographic areas of these satellite meetings follows in this issue:
Funding for ISIS Instrument upgrades
The EPSRC have recently funded major upgrades to the High Resolution Powder Diffractometer (HRPD) and the Single Crystal Diffractometer (SXD) at the ISIS pulsed neutron source at CLRC Rutherford Appleton Laboratory. The HRPD improvement involves the building of a much larger 90° detector bank, which will be of great benefit in studies of more complex structures such as zeolites and in magnetic powder diffraction studies. On SXD, the instrument will be essentially rebuilt, with an array of 11 position-sensitive area detectors surrounding the sample, allowing for the study of larger unit cell materials and smaller crystals. Work on both upgrades will begin shortly. Also funded by EPSRC is a new instrument for engineering stress measurements using the neutron strain-scanning technique. The successful ENGIN-X proposal was a collaboration headed by scientists from the Open University.
For further information contact:
or see the ISIS Web site on URL http://www.isis.rl.ac.uk/.
Chick Wilson,
email: [email protected]
The Sixth Oxford Summer School in Neutron Scattering
will take place at Mansfield College, Oxford from September 13th to
23rd 1999. It aims, by lecture and tutorial, to give a complete overview of
neutron scattering over a 2 week period and is directed towards Ph.D
students and post-docs. There are bursaries available, but numbers are
strictly limited to 40 participants.
Visit the website on: http://www.isis.rl.ac.uk/conferences/neutronsummerschool1999.htm
Colin Carlile, ISIS (email: [email protected])
Terry Willis, Oxford (email: [email protected])
The PEARL High Pressure Facility at ISIS - HiPr
The PEARL High Pressure Facility, HiPr, is a medium resolution neutron time-of-flight powder diffractometer designed to take full advantage of the capabilities offered by the Paris-Edinburgh pressure cell. Over the past decade this breakthrough in high-pressure technology has extended the pressure range available for neutron studies by almost a full order of magnitude. Funded by the EPSRC and constructed as a result of a close collaboration between the University of Edinburgh, the University of Paris VI and ISIS, HiPr is now available to the general ISIS user community.
HiPr is located on the PEARL beamline, which it shares with the dedicated engineering science facility (ENGIN). From the outset HiPr was designed to maximise the quality and quantity of information that could be collected from a given sample. As a consequence, the instrument permits the routine use of two scattering geometries. For the standard �transverse� geometry the incident beam passes through the front anvil of the pressure cell and diffraction data are collected over the angular range 83o<2q<97o, providing a useful d-spacing range of ~0.5<d<4.2 Å at a resolution of dd/d~0.8 %. The alternate �longitudinal� geometry, in which scattering takes place within the plane of the gasket, permits data collection from 2q=30o (useful for long d-spacings) up to 2q=150o (for relatively high resolution). Typical run times for refineable data range from 15 minutes for strongly scattering samples up to several hours for poorly scattering or structurally complex systems. At the time of writing, the CLRC high pressure programme at ISIS is able to offer routine operation over the pressure and temperature ranges 0-10 GPa (using tungsten carbide anvils) and 80-300 K, respectively. Higher pressures (up to 25 GPa) may be obtained using user-supplied sintered diamond anvils.
Despite the recent fully commissioned status of HiPr,
the list of completed and prospective high pressure structural studies
is already impressive and wide-ranging. Examples include studies of ice
phases VII and VIII, the ammonia hydrates, copper (II) oxide, iron sulphide,
cobalt deuteroxide, chalcopyrite, calcite and chlorite. The Paris-Edinburgh
collaboration also continues to go from strength to strength, with an extensive
instrument development and science programme.
Further details of this exciting development in high
pressure neutron diffraction may be obtained from the ISIS Instrument Scientist
(e-mail: [email protected]) or via the
PEARL web page
Bill Marshall, ISIS Facility
May 1998