16 Oct 2008



The High Resolution Powder Diffractometer, HRPD, is one of the highest resolution neutron powder diffractometers of its type in the world.

​​​​​​​​​View of HRPD’s sample position. The red shielding at the top surrounds the incident-beam guide and the backscattering detectors; the 90-degree banks sit underneath the platforms to left and right, and the low-angle bank is out of sight at the bottom right.

HRPD is situated ~ 96 m from the ISIS first target (TS-1) at the end of a supermirror neutron guide. This long primary flight path allows us to achieve a near Q-independent Δd/d ≈ 8x104 in backscattering geometry, making HRPD one of the highest-resolution neutron powder diffractometers in the world. This provides the ability to measure subtle changes in lattice parameters or peak splitting to very high precision and to observe subtle structural distortions, for example during phase transitions. The instrument's capacity to resolve closely-spaced peaks at short d-spacings makes HRPD an ideal tool for structure solution from powder data.




HRPD was constructed on beamline S8 on TS-1 (110 K methane moderator) as part of the “Day 1" instrument suite at ISIS in the mid-1980s. A number of upgrades to the detectors have subsequently been made, including replacement of the original Li-glass scintillation detectors in the backscattering bank with ZnS-based modules, the installation of a low-angle bank comprising 72 half-inch 3He tubes and, in 1999, the enhancement of the 90o bank funded by an EPSRC Instrument Development Call. In 2005, a bid to the CLRC Facility Development scheme provided funding of around £1.2M to replace the original neutron guide with a new supermirror guide, giving gains in flux at the sample of ~10x at wavelengths from 1 – 4 Å, and several times higher at shorter wavelengths, albeit at the expense of increased beam divergence.

Science Areas

  • High resolution powder diffraction studies across a range of scientific areas, including inorganic and organic chemistry, physics, materials science, Earth & planetary science and engineering.
  • Accurate structure refinement of complex materials with large unit cells and/or low symmetry (up to 2500 Å3).
  • High precision refinement of lattice parameters.
  • Characterisation of subtle and complex line-broadening phenomena.
  • Studies of structural and magnetic phase transitions.
  • Ab initio structure solution from powder data.

Instrument links: HRPD IBEX dashboard​​

​For further information about running an experiment on HRPD, contact Dr Dominic Fortes or Dr Christopher Howard​

Contact information for HRPD instrument​

Location and contact information for the HRPD beamline

Access Restricted
Building R69 - HRPD
Telephone 01235 445579