A sketch of the beamline which is located on a bending magnet source is shown below:

The beamline consists of only two optical elements:

• A toroidal pre-mirror which provides independent horizontal and vertical focusing.
• A toroidal grating to disperse the synchrotron radiation.

Two gratings are required to cover the wavelength range whilst maintaining sufficient resolution. The High Energy Grating (HEG) covers the wavelength range 100-350 nm, while the Low Energy Grating (LEG) covers 200-700 nm.

The entrance and exit slits are of fixed but selectable sizes in order to choose between different photon bandwidths. In order to maintain the correct focus at the exit slit as the grating rotates, it is necessary to translate the exit slit. This translation is mechanically linked to the experimental platform upon which the experiments are mounted. The range of this movement is about 65 mm over the full wavelength range.

UV1 optical specification

Optic	Major radius	Minor radius	Active area	Wavelength range
First mirror	3.947 m	0.3657 m	120 mm x 50 mm
LEG 1000 lines/mm	1.0 m	0.7755 m	40 mm x 40 mm	700 to 200 nm
HEG 2000 lines/mm	1.0 m	0.7755 m	40 mm x 40 mm	350 to 100 nm

Available slits

Slit	Available sizes
Entrance Slit	None	50 μm	100 μm	200 μm	500 μm
Exit Slit	None		100 μm	200 μm	500 μm	1000 μm

Resolution of UV1

Calculated resolution for the High Energy Grating (HEG) with 0.1 mm entrance and exit slits. The resolution is shown both for optimum grating to exit slit distance (r_grat), and for fixed r_grat.

Calculated resolution for the Low Energy Grating (LEG) with 0.1 mm entrance and exit slits. The resolution is shown both for optimum grating to exit slit distance (r_grat), and for fixed r_grat.

 

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Last Modified 17 August 2009