Compton scattering for single-shot spectroscopic detection of ultra-fast, high flux, broad energy range X-rays using Timepix

We show how Timepix, a pixelated, hybrid, semiconductor detector can be employed for single-shot spectrally resolved measurements of hard X-ray photons in the few KeV to MeV energy range. A novel detection scheme, based on Compton side-scattering, simultaneously increases the spectral range of the detector while allowing the flux to be attenuated to single photon levels. We use the detector to measure the spectrum of an intense beam of high energy betatron radiation photons produced by a laser plasma wakefield accelerator. Detectors with 300 m thick silicon and 1 mm thick cadmium telluride detector elements have been investigated and calibrated using laboratory sources. Modelling of photon scattering enables a detailed understanding of the geometry-dependent detector response to be developed. Single-shot spectra of high peak brilliance X-ray pulses have been successfully measured using the CdTe detector, with a significant flux of photons in the hundreds of keV range.