A brief description of R&D on cooling and mechanics. The all-silicon concept provides a self-supporting, ultra-transparent ladder design for applications where precision and material budget are key. We report results on the thermo-mechanical performance of all-silicon ladders in realistic conditions. A micro-channel cooling circuit has been integrated in the all-silicon ladder. The direct contact between coolant and heat source was shown to provide a thermal figure of merit that exceeds that of existing solutions significantly. This contribution gives an overview of progress so far and reports recent work to produce realistic all-silicon ladder prototypes with bump-bonded electronics.
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.
As a major part of an upgrade of its apparatus during the LHC Long Shutdown 2 in 2019/2020, ALICE will replace its Inner Tracking System (ITS) by a newly constructed silicon tracker based on Monolithic Active Pixel Sensors (MAPS).
By today, the design and R&D phase of the detector is completed, the design reviews of the different components are passed and the construction is underway.
This contribution gives an overview of the project and its organisation, highlighting challenges and crucial decisions that had to be taken to arrive to a working solution that can be implemented in time. Addressed items contain the qualification and selection of the pixel chip, its mass production and quality assurance, as well as the assembly of detector modules and their test.
Finally, the plans for the mechanical integration and electrical interfacing together with a timeline for commissioning and installation of the detector in the cavern are laid out.
Future experiments in particle physics require few-micrometer position resolution in their tracking detectors. Silicon is today's material of choice for high-precision detectors and offers a high grade of engineering possibilities. Instead of scaling down pitch sizes, which comes at a high price for
increased number of channels, our new sensor concept seeks to improve the position resolution by increasing the lateral size of the charge distribution already during the drift in the sensor material. To this end, it is necessary to carefully engineer the electric field in the bulk of this so-called
enhanced lateral drift (ELAD) sensor. This is achieved by implants with different values of doping concentration deep inside the bulk which allows for modification of the drift path of the charge carriers in the sensor.
In order to find an optimal sensor design, detailed simulation studies have been conducted using SYNOPSYS TCAD. The parameters that need to be defined are the geometry of the implants, their doping concentration and the position inside the sensor. Process simulations are used to provide the production-determined shapes of the implants in order to allow for a realistic modelling.
The electric field simulation demonstrates the possibility to locally engineer the electric field. The drift simulation confirms the feasibility of the ELAD concept. Results of a sensor design optimisation are shown realising an almost optimal charge sharing and hence position resolution. Additionally, the idea of a new multi-layer production process is presented, allowing for deep bulk engineering.
Surface and Underground Transportationa and Installation Proposals for CLIC
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