Jun 23 – 28, 2014
Europe/Zurich timezone

ImPACT: A Monte Carlo Template based analysis for Air-Cherenkov Arrays

Jun 23, 2014, 6:10 PM
Room 2 (Tuschinski Theatre)

Room 2

Tuschinski Theatre

Presentation Gamma-Ray Astrophysics Gamma-Ray Astrophysics


Dr Robert Parsons (Max-Planck-Institut für Kernphysik)


We present a high-performance event reconstruction algorithm: an Image Pixel-wise fit for Atmospheric Cherenkov Telescopes (ImPACT). This gamma-ray event reconstruction algorithm is based around the comparison of camera pixel amplitudes to an expected image template, performing a maximum likelihood fit to find the best-fit shower parameters. Related reconstruction algorithms have already been shown to provide significant improvements over traditional reconstruction techniques for both current and previous generation experiments. We demonstrate a significant improvement to the template generation step of the procedure, by the use of a full Monte Carlo air shower simulation in combination with a ray-tracing optics simulation to more accurately model the expected camera images. This reconstruction step is combined with an MVA-based background rejection. Application of the ImPACT analysis to both simulated and measured (from a strong VHE source) gamma-ray data from the H.E.S.S. array demonstrates an improvement in sensitivity of more than a factor two in observation time over traditional image moments-fitting methods, with comparable performance to previous likelihood fitting analyses. ImPACT is a particularly promising approach for future large arrays such as the Cherenkov Telescope Array (CTA) due to its improved high-energy performance and suitability for arrays of mixed telescope types.

Primary author

Dr Robert Parsons (Max-Planck-Institut für Kernphysik)


Jim Hinton (University of Leicester)

Presentation materials