Horizontal Bounce Monochromator
Horizontal-bounce monochromators are used when it is necessary to deflect a beam laterally into a branch beamline, as well as to select a particular photon energy. FMB Oxford has made a number of HBM variations which differ in terms of the number, orientation, and material of the crystals; the diffraction geometry (Bragg or Laue); and the design of the cooling system, which may use chilled water or liquid nitrogen. The accompanying photograph shows a HBM with two Silicon crystals of (220) and (311) orientations which can be selected using in-vacuum vertical travel. Both are nitrogen-cooled and can be finely controlled in pitch and roll, also through in-vacuum motors. Other crystal materials are available, including InSb and single-crystal diamond, and the customer may source their own crystals.
Beam stability requirements are often very stringent and include sub‑microradian pitch and roll control resolution and stability. Our HBM designs include a synthetic granite plinth for vibration rejection, and can also be enabled for real time feedback from a beam position monitor placed downstream.