Contact:
Ulrik Lund Olsen, DTU Fysik, ullu@dtu.dk
Figure 1: McXtrace tracing mode. The X-rays are sampled in a fan-beam geometry incident on a cubic sample and collected in an imaging spectral detector.
In airports, security screening of checked-in luggage is carried out with X-ray scanners, capable of identifying illegal content such as explosives, drugs or guns. In an effort to increase the screening accuracy, we are developing an innovative scanner that implements photon-counting detectors, able to detect the energy of the incoming photons. In this way, just like as a color photo camera, the energy spectral distribution is available for each acquisition, giving access to more information on the samples.
In X-ray scanners, to increase speed efficiency, the beam is typically shaped in fan- or cone-beam geometry. This can eventually lead to distortions in the energy distribution of the X-ray radiation. For example, for an X-ray filter in a fan collimated beam the penetration depth have an angular dependence. DTU Physics has developed a software package for Monte Carlo simulation of X-ray tracing optics and experiments (McXtrace http://www.mcxtrace.org/), which has been used to develop new techniques and to aid the optimization of synchrotron radiation sources.
Figure 2: X-ray instrument in building 309, including an X-ray source, a sample stage and a linear spectral detector.
In this project, you will use this framework to simulate X-ray experiments (Figure 1) using different parameters. Specifically you will develop the source component in the simulation to better encompass the angular dependence used for fan- and cone-beams. The results of the simulations will then be validated with real acquisitions using an instrumental setup established at DTU in building 309 (Figure 1). This will aid to understand and characterize the distortions in the energy distributions of the generated source. Finally, the results will be used both to enhance correction algorithms and to improve the simulation.
Skill requirements:
- Basic knowledge of C language or similar programming languages
- Basic knowledge of Matlab data analysis
Skills learned:
- Experience with software for ray tracing simulations
- Basics of X-ray experiments