1,720,974 research outputs found
Operational Experience and Performance with the ATLAS Pixel detector at the LHC.
No full textThe tracking performance of the ATLAS detector relies critically on its 4-layer Pixel Detector. As the closest detector component to the interaction point, this detector is subjected to a significant amount of radiation over its lifetime. At present, at the start of 2024-Run3 LHC collision ATLAS Pixel Detector on innermost layers, consisting of planar and 3D pixel sensors, will operate after integrating fluence of O(1015) 1 MeV n-eq cm-2. The ATLAS collaboration is continually evaluating the impact of radiation on the Pixel Detector. In this talk the key status and performance metrics of the ATLAS Pixel Detector are summarised, putting focus on performance and operating conditions with special emphasis to radiation damage and mitigation techniques adopted for LHC Run3. These results provide useful indications for the optimization of the operating conditions for the new generation of pixel trackers under construction for HL-LHC upgrades
Commissioning of the upgraded ATLAS Pixel Detector for Run2 at LHC
No full textThe Pixel Detector of the ATLAS experiment has shown excellent performance during the whole Run-1 of LHC. Taking advantage of the long showdown, the detector was extracted from the experiment and brought to surface, to equip it with new service quarter panels, to repair modules and to ease installation of the Insertable B-Layer (IBL). IBL is a fourth layer of pixel detectors, and has been installed in May 2014 between the existing Pixel Detector and a new smaller radius beam-pipe at a radius of 3.3 cm. To cope with the high radiation and pixel occupancy due to the proximity to the interaction point, a new read-out chip and two different silicon sensor technologies (planar and 3D) have been developed. Furthermore, the physics performance will be improved through the reduction of pixel size while, targeting for a low material budget, a new mechanical support using lightweight staves and a CO2 based cooling system have been adopted. An overview of the refurbishing of the Pixel Detector and of the IBL project as well as the experience in its construction will be presented, focusing on adopted technologies, module and staves production,qualification of assembly procedure, integration of staves around the beam pipe and commissioning of the detector. Early performance tests using cosmic and beam data will also be presented
Total Ionization Dose effects in the FE-I4 front-end chip of the ATLAS Pixel IBL detector
No full textDuring the first year of operation, a drift of the IBL calibration parameters (Threshold and ToT) and a low voltage current increase was observed. It was assumed that both observations were related to radiation damage effects depending on the Total Ionizing Dose (TID) in the NMOS transistors of which each Front End chip holds around 80 million. The effect of radiation on those transistors was investigated in lab measurements and the results will be presented in this talk
RD53 Wafer Testing for the ATLAS ITk Pixel Detector
No full textRD53 is the research and development group at CERN, responsible for developing and producing the next generation of readout chips for the ATLAS and CMS pixel detector upgrades at the HL-LHC. Its most recent development ITkPix is the first full-scale 65 nm hybrid pixel-detector. ITkPix consists of more than one billion transistors with a high triplication ratio in order to cope with the high particle and therefore radiation density at the heart of ATLAS. The chips will be located as close as possible to the interaction point to optimize impact parameter resolution. The ITkPix chip features a 5Gbit connection, with special data compression to deal with high hit intensities. In addition to that, a low power, low noise analog front-end is used, to ensure high readout speeds and low detection thresholds. A failure of chips at the heart of ATLAS is problematic. Therefore, thorough testing before and duringtheproduction phase is necessary. For thispurpose, Bonn has developed bdaq, a fast and versatile simulation, testing and analysis environment, making small-and large-scale testing for ITkPix and its successors possible. This talk will give an overview over the testing environment, while focusing on large scale wafer testing results to evaluatetheITkPix fitness for its deployment at the HL-LHC
Including radiation damage effects in ATLAS MonteCarlo simulations: status and perspectives
No full textSignal reduction is the most important radiation damage effect on performance of silicon tracking detectors in ATLAS. Adjusting sensor bias voltage and detection threshold can help in mitigating the effects but it is important to have simulated data that reproduce the evolution of performance with the accumulation of luminosity, hence fluence. ATLAS collaboration developed and implemented an algorithm that reproduces signal loss and changes in Lorentz angle due to radiation damage. This algorithm is now the default for Run3 simulated events. In this talk the algorithm will be briefly presented and results compared to first Run3 collision data. For the high-luminosity phase of LHC (HL-LHC) a faster algorithm is necessary since the increase of collision, event, track and hit rate imposes stringent constraints on the computing resources that can be allocated for this purpose. The philosophy of the new algorithm will be presented and the strategy on how to implement it and the needed ingredients will be discussed
The ATLAS ITk Pixel Detector. The biggest challenges from design to construction
No full textIn the HL-LHC era, the radiation is expected to reach unprecedented values, with non- ionizing fluence of 1e16 neq/cm2 and ionizing dose of 5 MGy. To cope with the resulting increase in occupancy, bandwidth, and radiation damage, the current ATLAS Inner Detector is replaced by an all-silicon system. The Pixel Detector will consist of five-barrel layers and a number of rings, resulting in about 13 m2 of instrumented area. The ITk pixel system has been very carefully designed including three different flavours of silicon hybrid detectors equipped with novel ASICS and data transmission chains. A new serial powering scheme has also been developed to minimize the amount of material in the detector. Along the lifetime of this project from design to prototyping (current) stages many challenges have been encountered and unforeseen problems have to be solved. In this contribution, an overview of the ITk pixel detector layout and the most challenging tasks resolved by now will be shown. From the mechanical point of view, the detector’s structure has to be robust and light providing support to the whole system, including local supports for modules and electronics, cables to power the detector and to drive the data in and out of the volume and cooling. All material and structures are designed to withstand all the possible conditions and cycles along the life of the detector. A customized cooling system will allow the operation of the detector at -35 C. Therefore, the detector will be exposed to a large number of temperature cycles that will stress it. Prototypes of mechanical supports systems at different stages of the project are tested and qualified. The environmental conditions at different locations within the pixel system will be monitored and linked to an interlock system that will protect the detector from major damages in case of any malfunction. Achieving that requires that the operation conditions of every pixel module are monitored by a Detector Control System (DCS). Due to the HL-LHC collisions rate, the data needs to be driven form the front-end chip to the opto-electrical conversion system with high-speed transmission parallel lines (TwinAx cables) running at 1.28 Gb/s per data link. An Optosystem features custom designed radiation-hard electronics devoted to signal equalization, aggregation (to 10.24 Gb/s) and opto-electrical conversion. Regarding the active part of the system, the pixel modules have gone through an extensive R&D program to identify what sensor technologies and thicknesses will be used in the final detector to achieve the best possible tracking performance. Prototypes have been already loaded on demonstrators and are going through exhaustive testing and qualification campaigns. The highlights of this effort together with the outcome can be expected within this contribution. At the end of this contribution the audience will get a good understanding of the status of the ATLAS-ITk pixel project and what have been the biggest challenges faced up to the day of this presentation and what are the major ones that we still have to overcome
Including radiation damage effects in ATLAS Monte Carlo simulations: status and perspective
No full textSignal reduction is the most important radiation damage effect on performance of silicon tracking detectors in ATLAS. Adjusting sensor bias voltage and detection threshold can help in mitigating the effects but it is important to have simulated data that reproduce the evolution of performance with the accumulation of luminosity, hence fluence. ATLAS collaboration developed and implemented an algorithm that reproduces signal loss and changes in Lorentz angle due to radiation damage. This algorithm is now the default for Run3 simulated events. In this paper the algorithm will be briefly presented and results compared to first Run3 collision data. For the high-luminosity phase of LHC (HL-LHC) a faster algorithm is necessary since the increase of collision, event, track and hit rate imposes stringent constraints on the computing resources that can be allocated for this purpose. The philosophy of the new algorithm will be presented
Including radiation damage effects in ATLAS MonteCarlo simulations: status and perspectives
No full textSignal reduction is the most important radiation damage effect on performance of silicon tracking detectors in ATLAS. Adjusting sensor bias voltage and detection threshold can help in mitigating the effects but it is important to have simulated data that reproduce the evolution of performance with the accumulation of luminosity, hence fluence. ATLAS collaboration developed and implemented an algorithm that reproduces signal loss and changes in Lorentz angle due to radiation damage. This algorithm is now the default for Run3 simulated events. In this talk the algorithm will be briefly presented and results compared to first Run3 collision data. For the high-luminosity phase of LHC (HL-LHC) a faster algorithm is necessary since the increase of collision, event, track and hit rate imposes stringent constraints on the computing resources that can be allocated for this purpose. The philosophy of the new algorithm will be presented and the strategy on how to implement it and the needed ingredients will be discussed
Operational experience and performance with the ATLAS pixel detector at the large hadron collider at CERN
No full textThe tracking performance of the ATLAS detector relies critically on its 4-layer Pixel Detector, that has undergone significant hardware and readout upgrades to meet the challenges imposed by the higher collision energy, pileup and luminosity that are being delivered by the Large Hadron Collider (LHC), with record breaking instantaneous luminosities of 2 x 1034 cm-2 s-1 recently surpassed. The key status and performance metrics of the ATLAS Pixel Detector are summarised, and the operational experience and requirements to ensure optimum data quality and data taking efficiency will be described, with special emphasis to radiation damage experience
The Phase-2 ATLAS ITk Pixel Upgrade
No full textThe entire tracking system of the ATLAS experiment will be replaced during the LHC Phase II shutdown (foreseen to take place around 2025) by an all-silicon detector called the “ITk” (Inner Tracker). The innermost portion of the ITk will consist of a pixel detector with stave-like support structures in the most central region and ring-shaped supports in the endcap regions; there may also be novel inclined support structures in the barrel-endcap overlap regions. The new detector could have as much as 14 m2 of sensitive silicon. Support structures will be based on low mass, highly stable and highly thermally conductive carbon-based materials cooled by evaporative carbon dioxide. The ITk will be instrumented with new sensors and readout electronics to provide improved tracking performance compared to the current detector. All the module components must be performant enough and robust enough to cope with the expected high particle multiplicity and severe radiation background of the High-Luminosity LHC. Readout will be based on the new front-end ASIC being developed by the RD53 Collaboration. Ideally the readout chips will be thinned to as little as 100 m to save material; this presents a challenge for sensor-chip interconnection and options are being evaluated in collaboration with industrial partners to develop reliable processing techniques. Servicing the detector reliably without introducing excessive amounts of material and dead space is another significant challenge. Data cables must be capable of handling up to 5 Gb/s and must be electrical in nature, with optical conversion at larger radii where the radiation background is less intense. Serial powering has been chosen as the baseline for the ITk pixel system as it minimises service cable mass; extensive testing has been carried out to prove its feasibility. Attention must also be paid to grounding and shielding in the detector to mitigate cross-talk and common mode noise. Most of the baseline technological decisions will be taken this year in view of the ITk Pixel TDR to be completed by the end of 2017
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