Recent results with HV-CMOS and planar sensors for the CLIC vertex detector

The physics aims for the future multi-TeV e+e- Compact Linear Collider (CLIC) impose high precision requirements on the vertex detector which has to match the experimental conditions, such as the time structure of the collisions and the presence of beam-induced backgrounds. The principal challenges are: a point resolution of 3μm, 10 ns time stamping capabilities, low mass (⇠0.2% X0 per layer), low power dissipation and pulsed power operation. Recent results of test beam measurements and GEANT4 simulations for assemblies with Timepix3 ASICs and thin active-edge sensors are presented. The 65 nm CLICpix readout ASIC with 25μm pitch was bump bonded to planar silicon sensors and also capacitively coupled through a thin layer of glue to active HV-CMOS sensors. Test beam results for these two hybridisation concepts are presented

Test-beam measurements and simulation studies of thin pixel sensors for the CLIC vertex detector

The multi- TeV e+e− Compact Linear Collider (CLIC) is one of the options for a future high-energy collider for the post-LHC era. It would allow for searches of new physics and simultaneously offer the possibility for precision measurements of standard model processes. The physics goals and experimental conditions at CLIC set high precision requirements on the vertex detector made of pixel detectors: a high pointing resolution of 3 μm, very low mass of 0.2% X0 per layer, 10 ns time stamping capability and low power dissipation of 50 mW/cm2 compatible with air-flow cooling. In this thesis, hybrid assemblies with thin active-edge planar sensors are characterised through calibrations, laboratory and test-beam measurements. Prototypes containing 50 μm to 150 μm thin planar silicon sensors bump-bonded to Timepix3 readout ASICs with 55 μm pitch are characterised in test beams at the CERN SPS in view of their detection efficiency and single-point resolution. A digitiser for AllPix, a Geant4-based simulation framework, has been developed in order to gain a deeper understanding of the charge deposition spectrum and the charge sharing in such thin sensors. The AllPix framework is also used to simulate the beam telescope and extract its tracking resolution. It is also employed to predict the resolution that can be achieved with future assemblies with thin sensors and smaller pitch. For CLIC, a full coverage of the vertex detector is essential while keeping the material content as low as possible. Seamless tiling of sensors, without the need for overlaps, by the active-edge technology allows for extending the detection capability to the physical edge of the sensor and thereby minimising the inactive regions. Thin-sensor prototypes containing active edges with different configurations are characterised in test-beams in view of the detection performance at the sensor edge. Technology Computer-Aided Design (TCAD) finite- element simulations are implemented to reproduce the fabrication and the operation of such devices. The simulation results are compared to data for different edge terminations

Optimisation studies for the CLIC vertex-detector geometry

A new detector concept is currently under development for the proposed multi-TeV linear e+e− Compact Linear Collider (CLIC). The impact of the detector geometry on the physics performance of the CLIC vertex detector is being investigated. Different options for the barrel detector and alternative layouts of the endcap regions fulfilling engineering requirements while minimising the material budget are considered. This study is based on a full detector simulation using GEANT4. The beauty and charm flavour-tagging performances for different jet energies and polar angles are the key observables used to compare the different investigated detector configurations.ISSN:1748-022

Simulation and tracking studies for a drift chamber at the FCC-ee experiment

The physics aims at the electron-positron option for the Future Circular Collider (FCC-ee), impose high precision requirements on the vertex and tracking detectors. The detector has also to match the experimental conditions such as the collisions rate and the presence of beam-induced backgrounds. A light weight tracking detector is under investigation for the IDEA (InternationalDetector for Electron-Positron Accelerator) detector concept and consists of a drift chamber. Simulation studies of the drift chamber using the FCCSW (FCC software) are presented. Full simulations are used to study the effect of beam-induced backgrounds on this detector. Tracking for the drift chamber of the IDEA detector is also investigated using the Hough transformation method. A technical documentation on running the different software components is as well provided

Performance-Optimization Studies for the CLIC Vertex Detector

The Compact Linear Collider (CLIC) is a mutli-TeV linear e+e- collider currently under development at CERN. In the post-LHC era, CLIC will allow to explore a great number of searches for New Physics such as the precise measurements of the Higgs boson. In this master thesis, we mainly focus on the development and the improvement of the vertex detector. The vertex detector requires excellent spatial resolution, low mass, geometrical coverage down to low polar angles, high rate readout for the sensors and new cooling technologies for heat removal. Considering such requirements, the CLIC vertex detector technology is far more advanced in comparison to the technologies currently used in particle physics. This project consists of two main parts. In the first part, we study the vertex detector and optimize its geometry for the use of airflow cooling techniques and also for flavor tagging. In the second part, we implement a decoder which can respect the timing constraints for the CLICpix chip, a silicon pixel detector developed for the CLIC vertex detector

CLIC vertex detector R&D

A vertex-detector concept is under development for the proposed multi-TeV linear e+e- Compact Linear Collider (CLIC). To perform precision physics measurements in a chal- lenging environment, the CLIC vertex detector pushes the technological requirements to the limits. This paper reviews the requirements for the CLIC vertex detector and gives an over- view of recent R&D achievements in the domains of sensor, readout, powering and cooling