Beam Telescope and Test Beam Workshop 6

Abstracts

Allpix Squared - A Generic Pixel Detector Simulation Framework

• Speaker: Simon Spannagel (CERN)
• Status: Accepted
• Abstract: Allpix Squared is a generic open-source simulation framework for pixel detectors. Its goal is to ease the implementation of detailed simulations for both single detectors and more complex setups such as beam telescopes. Predefined detector types can be automatically constructed from simple model files describing the detector parameters. The simulation chain is arranged with the help of intuitive configuration files and an extensible system of modules, which implement the separate simulation steps. Currently available modules include realistic charge carrier deposition using the Geant4 toolkit, propagation of charge carriers in silicon either using a drift-diffusion model or a projection onto the sensor implants, and a simulation of the detector front-end electronics including noise, threshold, and digitization. Detailed electric field maps imported from TCAD simulations can be used to precisely model the drift behavior of the charge carriers, bringing a new level of realism to the simulation of particle detectors. The history of every simulated object, including the Monte Carlo truth information of the original ionizing radiation, is preserved and can be stored to file, allowing for a direct comparison with reconstructed position information. The framework is written in modern C++ and comes with fully documented source code as well as an extensive user manual. Its modular approach allows for a flexible set-up of the simulation and facilitates the reuse of independent, well-tested algorithms. This contribution provides an overview of the framework and its different simulation modules, and presents first comparisons with test beam data.
• Slides

Highlights from the 2017 beam tests with the CLICdp Timepix3 telescope

• Speaker: Andreas Matthias Nurnberg (CERN)
• Status: Submitted
• Abstract: The vertex- and tracking detectors at the proposed high-energy CLIC electron-positron collider will be based on small-pitch silicon pixel- or strip detectors. The requirements for these detectors include single-point position resolutions of a few microns combined with nanosecond time tagging of hits. Tests with particle beams are needed to assess the performance of existing and future prototype assemblies. To this end the CLIC detector and physics collaboration (CLICdp) operates a high-resolution beam telescope in the H6 beam line of the CERN SPS. It is based on Timepix3 hybrid pixel-detector assemblies with data-driven readout, allowing for track reconstruction at high particle rates (up to 10 million tracks / second) and with excellent spatial (<~2 microns) and temporal (<~1 ns) resolution. Several pixel detector prototypes with different readout architectures have been integrated into the telescope DAQ system and operated with high-energy hadron beams. We discuss performance results for the CLICdp reference telescope, the event building and reconstruction methods for various devices under test and show examples of ongoing data analyses.
• Slides

Single-layer track reconstruction using drift-time

• Speaker: Morag Williams (University of Glasgow, CERN)
• Status: Submitted
• Abstract: A precise measurement of the arrival time distribution of ionisation charges in a reverse-biased single silicon pixel sensor layer can be used to determine the impact point, incident angle and direction of minimum ionising particles. This concept of a Silicon Time-Projection-Chamber could for example be used to reduce the number of sensor layers in large-area tracking detectors, or to improve the track-prediction resolution of beam telescopes with inclined sensor planes. First tests of the concept have been performed using sensors of different thicknesses with 55 micron pitch and Timepix3 readout in a 120 GeV hadron beam at the CERN SPS. The fine binning of 1.56 ns for the Timepix3 arrival time measurement allows for a precise determination of the depth of charge deposition in each pixel. This information is used in a multi-variate analysis in combination with the charge measurement and cluster shape, in order to reconstruct the track impact point, incident angle and direction. The CLICdp Timepix3 beam telescope in the H6 beam line of the SPS is used as a reference detector to predict the track position and incident angle on the device under test (DUT). In this contribution we introduce the multi-variate track reconstruction method for the DUT and present results for different sensor thicknesses and various track incident angles.
• Slides