Pearl technical information
14 Aug 2009




The PEARL High Pressure Facility (HiPr), is a medium resolution high-flux diffractometer optimised for data collection from the Paris-Edinburgh pressure cell


Technical Summary

LocationISIS beamline S9
Moderator100K CH4
Flight-pathsL1= 12.8 m, L2= 0.8 m (all detectors as of June 2011; the new low angle bank will be located at L2= 1.2m)
Scattering geometries
  1. ‘transverse’ (through-anvil) setting for access to the main detector bank covering 81.2° < 2q < 98.8°
  2. ‘longitudinal’ (through-gasket) setting for access to 20° < 2q < 60° (to be installed March 2012) and 100° < 2q < 160°

Twelve detector modules in total (June 2011), each consisting of 78 ZnS scintillator elements of 3mm width viewed in 2q. The scintillator elements are fibre-optically coupled to 15 photo-multiplier tubes using a modified 2CN15 coding scheme.

Nine detector modules constitute the main ‘transverse’ bank covering 81.2° < 2q < 98.8°, giving a 20ms frame d-spacing range of ~0.5 - 4.1 Å, with resolution Dd/d ~ 0.65%. These detectors are used for the standard (though-anvil) scattering geometry of the Paris-Edinburgh pressure cell.

At present the ‘longitudinal’ bank consists of three detector modules covering the back-scattering range 100° < 2q < 160°. A new large low-angle module covering 20° < 2q < 60° will be installed in early 2012.

Data AcquisitionDell Power Edge rack mounted R200 server PC