Community Research and Development Information Service - CORDIS

Final Activity Report Summary - ELACCO (Electronics, acquisition and controls developments for physics experiments)

Research was mostly concerned with the large hadron collider (LHC) experiments, but also with technology spin-off and electronics for future particle detectors. Ten early stage researchers (ESTs) worked on development, installation and commissioning of data acquisition and control systems for the large ion collider experiment (ALICE), ATLAS, CMS and large hadron collider beauty (LHCb) detectors. Two ESTs designed integrated circuits for the readout of future detectors. Another worked on power distribution schemes for detector-embedded electronics. One was involved in imaging detectors based on the LHC's pixel tracking technology. Hybrid pixel detectors, as used in all the LHC experiments, combined the processing power of advanced complementary metal-oxide semiconductor (CMOS) technology with leading edge packaging techniques to provide fast and practically noise-free data.

Medipix, a spin-off project, used a similar approach to bring new possibilities to medical and other imaging applications. A custom digital circuitry was designed for the 'Medipix3' chip and integrated into a prototype layout fabricated in 130 nm CMOS technology. Specifications for the next Medipix3 chip were drawn up and analog and digital pixel circuits were designed. CMOS integrated front-end electronics were developed for readout of silicon detectors for particle tracking at LHC detector upgrades. Challenges were to:

1. minimise power
2. optimise noise performance
3. achieve high timing accuracy and radiation hardness.

The prototype functioned well and was used to develop future detectors. Amorphous silicon thin film on application-specific integrated circuit (ASIC), i.e. TFA, technology was investigated for particle tracking at future linear colliders. Noise performance measurements made with amorphous silicon films deposited on an evaluation ASIC showed the need to improve the TFA deposition process. A new approach to powering embedded chips in future upgrades to LHC experiments used switching direct current to direct current (DC/DC) converters bringing in power at high voltage and low current. Requirements were toleration of high radiation levels and high magnetic fields, high efficiency and low emitted noise. A converter suitable for LHC upgrades was designed and fabricated in a 250 nm technology.

A demonstrator chip for readout of time projection chambers (TPC) was designed and submitted to fabrication. It had 16 signal channels and integrated analog filters, analog to digital conversion (ADC) and digital signal processing (DSP) functions all on the same chip.

For the ALICE data acquisition system (DAQ) an electronic logbook was developed and supported for users. It recorded environment parameters and subsystem status information later needed for analysis of the DAQ data. Significant contributions were made to the development and commissioning of the detector control system (DCS) with a tool for building homogeneous style user interfaces across the various detector subsystems.

For ATLAS, important contributions were made to commissioning and optimising event building and data logging systems using cosmic rays and the first LHC circulating beams. The event builder assembled data fragments from different parts of the detector into one common data structure. The data logging system was responsible for temporary storage of the experiment's data and its movement to off-line data analysis centres. Important contributions were made to installing, commissioning and optimizing the DCS.

For CMS, engineering changes to introduce fault tolerance in the event building software of the DAQ system were documented and a test environment to validate them was provided. 'Trigger supervisor' software was developed, providing a framework to set up, test, operate and monitor the trigger components, which selected only 'interesting' events from the raw event stream.

A web-based tool development allowed off-site users to coordinate participation in data taking shifts. For LHCb, effort was provided for configuration, management and optimisation of the experiment's data storage system. Software was developed for high-performance file migration between the online system and the computer centre. An interface between the experiment control system and the conditions database, i.e. a repository for all parameters needed for offline analysis of physics data, was developed and commissioned.

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