Characterisation of a new VUV beamline at the Daresbury SRS using a dispersed fluorescence apparatus incorporating CCD detection

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Beam interactions with materials and atoms, 2005-08, Vol.237 (3), p.656-665
• Main Authors: Howle, Chris R., Ali, Sahangir, Tuckett, Richard P., Shaw, David A., West, John B.
• Format: Article
• Language: English
• Subjects: Beamline; CCD detection; Dispersed fluorescence; Synchrotron; Wadsworth
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/j.nimb.2005.03.287

The design and performance of a new normal incidence monochromator at the Daresbury Synchrotron Radiation Source, optimised for experiments requiring high flux of vacuum-UV radiation, are described. The re-developed beamline 3.1, based on the Wadsworth design of monochromator, is the source of tunable vacuum-UV photons in the range 4–31 eV, providing over two orders of magnitude more flux than the vacuum-UV, Seya monochromator in its previous manifestation. The undispersed and dispersed fluorescence spectra resulting from photoexcitation of N 2, CO 2, CF 4 and C 6F 6 are presented. Emitting species observed were N 2 + B 2 Σ u + – X 2 Σ g + , CO 2 + A ˜ 2 Π u – X ˜ 2 Π g and B ˜ 2 Σ u + – X ˜ 2 Π g , CF 4 + C ˜ 2 T 2 – X ˜ 2 T 1 and C ˜ 2 T 2 – A ˜ 2 T 2 , CF 3 ∗ 2 A 2 ′ – 2 A 2 , and C 6 F 6 + B ˜ 2 A 2 u – X ˜ 2 E 1 g . A CCD multi-channel detector has significantly reduced the time period needed to record dispersed fluorescence spectra with a comparable signal-to-noise ratio.