Key points

• Energy range 20 < E < 500 KeV
• Beam sizes from 0.3 µm to 8 mm

Overall layout

The ID15 straight section houses a complex of beam lines, with two canted branches. This web site is dedicated to the ID15A branch, which houses the materials chemistry (EH3) and materials engineering (EH2) facilities. The ID15B branch houses a high pressure beam line (EH1), which is described elsewhere. The overall layout is shown below:

X-ray source

Upon resuming user opertion in 2020, ID15A will house two new insertion devices. One is a compact wiggler source W76, which provides a continuous spectrum up to several hundred keV for materials engineering applications in EH2. The spectrum of this device, compared to that of the former wiggler source, is shown below.

The primary insertion device will be a CPMU18 undulator, which provides brilliant x-rays in the range 20 -140 keV for materials chemistry applications in EH3. A comparison of the performance of the ID15A sources before and after the upgrade is shown below, illustrating the significant flux increase, particularly at high energy.

X-ray optics

For EH2, it is envisioned that the white beam will be shaped by high heat load slits, with a maximum beam size of 8 x 6 mm². Provision has been made for mounting a high-energy monochoromator (in air) at the entrance to the hutch. This can be equipped with Ge crystals for exotic high-energy monochromatic scattering experiments.

For EH3, two monochromators are available. The first is a double multilayer mirror (DMLM) at 40 m from the source in OH1. This provides very high flux at the expense of a band pass of around 0.37 %, and is particularly useful in the lower engery range of the beamline. The second monochromator is a liquid nitrogen cooled double Laue Si monochromator (LLM) mounted in OH2. This provides excellent flux and tunability over the range 40 - 140 keV. The band pass may be tuned from 0.01 to 0.5 % by bending the crystals.

Several options for X-ray focussing are available for monchromatic beams. Transfocators, which consist of motorized cartridges of X-ray refractive lenses are employed. To make the best use of the anisotropic X-ray source, vertical and horizontal focusing are carried out using 1D Aluminium and Berylium lenses at 32 and 53 m respectively. The beam size in EH3 can be tuned down to around 10 µm using these white beam transfocators.

Additional focusing to beam sizes down to 0.3 µm is available using further refractive lenses placed at the entrance to EH3 or a KB-mirror system. The optical layout of the beamline is shown below.

The available optical schemes (in EH3) are listed in the following table.