Increasing photon pair production in x-ray parametric down-conversion

The use of correlated – or even entangled – photon pairs for quantum imaging bears enormous potential to exploit new contrast modalities and to reduce dose in X-ray imaging. A promising source of such pairs is the process of X-ray parametric down-conversion. However, it is intrinsically weak – with reported count rates reaching only about 6000 photon-pairs/hour. In order to enable practical applications in X-ray imaging, it is imperative to increase the useable count rate significantly. To achieve this goal, we propose an experiment that will improve both the amount of produced photon pairs (by the exceptional flux density of beamline ID19 – using its pink single-harmonic undulator beams) well as the efficiency of their detection (by the improved detection efficiency using the novel Timepix4-based TEMPUS detector in tandem-configuration). This setup could increase the useable count rate by ~1000×. This increase would render low-dose, quantum X-ray imaging truly viable for first time.