Silicon-based beam-alignment monitor tool keeps X-rays on track

October 18, 2013 // By Graham Prophet
A collaboration between Diamond Light Source, the UK’s national synchrotron science facility, and the University of Manchester’s School of Electrical and Electronic Engineering has built a new beam imaging instrument, the Lancelot X-ray Beam Position Monitor (XBPM).

The device, which incorporates the advanced silicon chip Medipix3 technology, will help scientists using Diamond to monitor the alignment of the micrometer-sized X-ray beams as they travel, first through the instrumentation that refines them and then on to the samples being studied with the intense synchrotron light produced by the facility’s 562m storage ring. The stability of the synchrotron radiation beams produced at Diamond is crucial to the success of experiments using smaller and smaller X-ray beams to analyse material or biochemical samples.

The Diamond Light Source , located near Oxford, UK, generates extremely intense pin-point beams of synchrotron light of exceptional quality ranging from X-rays, ultra-violet and infrared. For example Diamond’s X-rays are around 100 billion times brighter than a standard hospital X-ray machine.

The goal of the Lancelot X-ray Beam Position Monitor (XBPM) project has been to devise a ‘transparent’ instrument for measuring in real-time beam intensity, beam position, and the shape of the beam cross section, with better quality images and lower noise profiles than currently available systems. The project has successfully produced a device that can effectively provide live images of the beam without blocking it with highly absorbing media. This is of huge benefit as it gives scientists access to real-time information on the position of the incident beam, enabling them to identify issues that can arise with the X-ray optics.

Julien Marchal, Senior Detector Scientist at Diamond, explains, “The need for improved X-ray beam position control during experiments led us to set up the Lancelot XBPM project with the University of Manchester. The Manchester team had already demonstrated considerable success in the area of in situ beam imaging utilising a pinhole camera system based on commercial CCDs or CMOS sensors, which are similar to the imaging systems used by conventional commercial digital cameras. The idea behind our project was to replace the standard X-ray sensor used in this pinhole camera with the new X-ray