Principal Beamline Scientist:
Georg Held
Tel: +44 (0) 1235 778480
E-mail: [email protected]
Email: [email protected]
Tel: +44 (0)1235 778290
PHOIBOS 150 NAP Analyser
The electron energy analyser is a "PHOIBOS 150 NAP" hemispherical analyser supplied by SPECS, Berlin, Germany (left image). The analyser axis is at an angle of 60.1° with respect to the beam and tilted 30° with respect to the horizontal, i.e. close to the magic angle with respect to the polarization vector (right image). The entire assembly of interface ange and analyser is mounted on a "sledge" which can be moved parallel to the analyser axis. This way the cone-to-beam/sample distance can be changed without having to re-align the endstation, once the beam and the analyser axis have been adjusted such that they intersect in one point. The typical working distance between cone and sample is 0.2 - 0.3 mm. Compensation of residual magnetic fields is achieved via three pairs of Helmholtz coils, are individually controlled as a function of electron energy through the control unit of the electron energy analyser.
Total Electron Yield – Drain current for NEXAFS
The entry cone of the analyser's pre-lens has an aperture of 0.3mm and is isolated from ground to allow collection of TEY NEXAFS by measuring the drain current through a Stanford Research SR 570 current amplifier (image below). In total, four currents can be recorded simultaneously:
Signal | Current Amplifier (old GDA name) | Current Amplifier (GDA name) |
I0 (Au mesh) | ca20 | ca31c |
BLE nozzle | ca21 | ca32c |
analyser cone | ca22 | ca33c |
sample drain current | ca23 | ca34c |
Current Amplifier Squemes: left, centre and right
Diamond Light Source is the UK's national synchrotron science facility, located at the Harwell Science and Innovation Campus in Oxfordshire.
Copyright © 2022 Diamond Light Source
Diamond Light Source Ltd
Diamond House
Harwell Science & Innovation Campus
Didcot
Oxfordshire
OX11 0DE
Diamond Light Source® and the Diamond logo are registered trademarks of Diamond Light Source Ltd
Registered in England and Wales at Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom. Company number: 4375679. VAT number: 287 461 957. Economic Operators Registration and Identification (EORI) number: GB287461957003.