The Malvern Panalytical Empyrean Mo diffractometer was installed in the department in 2010. Its has a high intensity configuration without monochromation. The instrument was initially configured for PDF data collection and can still be configured for such, but in recent times has been repurposed for low temperature powder diffraction. It is equipped with a PheniX cryostage, which is a low temperature module made by Oxford Cryosystems, capable of cooling and warming a powder sample between 300 and 15 K. The instrument is currently running with a molybdenum tube, with a silver tube in storage.
Low temperature configuration:
Source: Mo
Beta radiation filtering: Zr filter in secondary position (moveable)
Alpha 2 radiation filtering: none
Primary optics, defaults in bold:
- 0.02, 0.04 radian (or removed) changeable soller slits,
- 5, 10, 15, 20mm mask,
- programmable divergence slit (default is for 13mm constant sample illumination)
- fixed primary antiscatter slit, changeable from 1/32 to 4 degree (default is none)
secondary optics:
- 0.02, 0.04 radian (or removed) changeable soller slits
- programmable antiscatter slit (default 13mm constant sample illumination)
Detector: Xcelerator, low backround silicon strip direct detector with a 2.122 degree active length.
Sample Stages: PheniX cryostage, with automatic sample height adjustment. Temperature control 15-300 K
Sample holders: flat plate; powder attached by Apiezon N cryogenic grease to a Cr plated Cu disk or recession cup; powder pressed into cup, ideally as a pellet.
Min/ Max angle: 4.5 - 120 (typical required end point is ~40 degrees with Mo radiation)
Typical collection time: 2 hours per temperature
PDF configuration:
Source: Mo (Ag currently out of use)
Beta radiation filtering: by focussing mirror
Alpha 2 radiation filtering: none
Primary optics, defaults in bold:
- 0.02, 0.04 radian (or removed) changeable soller slits,
- 5, 10, 15, 20mm mask,
- focussing mirror (separate mirrors available for Mo and Ag)
- fixed primary antiscatter slit, changeable from 1/32 to 4 degree
secondary optics:
- 0.02, 0.04 radian (or removed) changeable soller slits
- programmable antiscatter slit (default is 1/32)
Detector: X'Celerator, low background silicon strip direct detector with a 2.122 degree active length. Scintillation detector available for Ag radiation. A GaliPIX CdTe strip direct detector can be attached to the instrument for better counting statistics and lower background, but is currently in need of repair (a new water chiller and reconfiguration)
Sample Stages: Capillary spinner stage.
Min/ Max angle: 2 - 150 (beamstop covering angles below 3)
