Optimisation of pixel modules for the ATLAS inner tracker at the high-luminosity LHC

The Large Hadron Collider and its pre-accelerator complex will be upgraded in three steps to allow for the high luminosity phase. A factor of ten times more data will be collected in this period by facilitating the increased instantaneous luminosity being seven times as large as the original design value. A new inner tracker system is in preparation for the ATLAS detector in view of the high luminosity phase to start operation around 2026. This all silicon tracker relies on various innovative technologies to cope with the severe challenges arising from the increased luminosity. The pixel detector employs a new readout chip to decrease the pixel size to a fifth of the pixel size of the present generation to be able to disentangle all tracks in the high multiplicity environment close to the interaction point. Thanks to their reduced power dissipation and high charge collection efficiency after irradiation, thin planar n-in-p pixel sensors are ideally suited to cope with the expected unprecedented radiation damage. TCAD simulations are being performed to optimise the sensor layout for the new pixel cell size of 50x50um2. In this study, charge collection efficiency, electronic noise and electrical field properties are investigated both before and after irradiation. The RD53A prototype readout chip is used to build modules based on the proposed thin planar n-in-p sensors. The performance of different sensor designs is assessed by analysing data from various test-beam campaigns. The effects of storage time at room temperature for the ITk pixel detector during maintenance periods are reproduced on real modules. Pixel detector modules built with sensors of 100-150um thickness are characterised with testbeam measurements. The charge collection and hit efficiencies are compared before and after annealing at room temperature up to one year

Optimization of thin n-in-p planar pixel modules for the ATLAS upgrade at HL-LHC

The ATLAS experiment will undergo around the year 2025 a replacement of the tracker system in view of the high luminosity phase of the LHC (HL-LHC) with a new 5-layer pixel system. Thin planar pixel sensors are promising candidates to instrument the innermost region of the new pixel system, thanks to the reduced contribution to the material budget and their high charge collection efficiency after irradiation. The sensors of 50-150 $\mu$m thickness, interconnected to FE-I4 read-out chips, have been characterized with radioactive sources and beam tests. In particular active edge sensors have been investigated. The performance of two different versions of edge designs are compared: the first with a bias ring, and the second one where only a floating guard ring has been implemented. The hit efficiency at the edge has also been studied after irradiation at a fluence of $10^{15}$ \neqcm. Highly segmented sensors will represent a challenge for the tracking in the forward region of the pixel system at HL-LHC. In order to reproduce the performance of 50x50 $\mu$m$^2$ pixels at high pseudo-rapidity values, FE-I4 compatible planar pixel sensors have been studied before and after irradiation in beam tests at high incidence angles with respect to the short pixel direction. Results on the hit efficiency in this configuration are discussed for different sensor thicknesses

Optimisation of pixel modules for the ATLAS inner tracker at the high-luminosity LHC

The Large Hadron Collider and its pre-accelerator complex will be upgraded in three steps to allow for the high luminosity phase. A factor of ten times more data will be collected in this period by facilitating the increased instantaneous luminosity being seven times as large as the original design value. A new inner tracker system is in preparation for the ATLAS detector in view of the high luminosity phase to start operation around 2026. This all silicon tracker relies on various innovative technologies to cope with the severe challenges arising from the increased luminosity. The pixel detector employs a new readout chip to decrease the pixel size to a fifth of the pixel size of the present generation to be able to disentangle all tracks in the high multiplicity environment close to the interaction point. Thanks to their reduced power dissipation and high charge collection efficiency after irradiation, thin planar n-in-p pixel sensors are ideally suited to cope with the expected unprecedented radiation damage. TCAD simulations are being performed to optimise the sensor layout for the new pixel cell size of 50x50um2. In this study, charge collection efficiency, electronic noise and electrical field properties are investigated both before and after irradiation. The RD53A prototype readout chip is used to build modules based on the proposed thin planar n-in-p sensors. The performance of different sensor designs is assessed by analysing data from various test-beam campaigns. The effects of storage time at room temperature for the ITk pixel detector during maintenance periods are reproduced on real modules. Pixel detector modules built with sensors of 100-150um thickness are characterised with testbeam measurements. The charge collection and hit efficiencies are compared before and after annealing at room temperature up to one year

Performance of irradiated thin n-in-p planar pixel sensors for the ATLAS Inner Tracker upgrade

The ATLAS collaboration will replace its tracking detector with new all silicon pixel and strip systems. This will allow to cope with the higher radiation and occupancy levels expected after the 5-fold increase in the luminosity of the LHC accelerator complex (HL-LHC). In the new tracking detector (ITk) pixel modules with increased granularity will implement to maintain the occupancy with a higher track density. In addition, both sensors and read-out chips composing the hybrid modules will be produced employing more radiation hard technologies with respect to the present pixel detector. Due to their outstanding performance in terms of radiation hardness, thin n-in-p sensors are promising candidates to instrument a section of the new pixel system. Recently produced and developed sensors of new designs will be presented. To test the sensors before interconnection to chips, a punch-through biasing structure has been implemented. Its design has been optimized to decrease the possible tracking efficiency losses observed. After irradiation, they were caused by the punch-through biasing structure. A sensor compatible with the ATLAS FE-I4 chip with a pixel size of 50x250 $\mathrm{\mu}$m$^{2}$, subdivided into smaller pixel implants of 30x30 $\mathrm{\mu}$m$^{2}$ size was designed to investigate the performance of the 50x50 $\mathrm{\mu}$m$^{2}$ pixel cells foreseen for the HL-LHC. Results on sensor performance of 50x250 and 50x50 $\mathrm{\mu}$m$^{2}$ pixel cells in terms of efficiency, charge collection and electric field properties are obtained with beam tests and the Transient Current Technique

Higher occurrence of nausea and vomiting after total hip arthroplasty using general versus spinal anesthesia: an observational study.

BACKGROUND: Under the assumption that postoperative nausea and vomiting (PONV) may occur after total hip arthroplasty (THA) regardless of the anesthetic technique used, it is not clear whether general (GA) or spinal (SA) anesthesia has higher causal effect on this occurrence. Conflicting results have been reported. METHODS: In this observational study, we selected all elective THA interventions performed in adults between 1999 and 2008 in a Swiss orthopedic clinic under general or spinal anesthesia. To assess the effect of anesthesia type on the occurrence of PONV, we used the propensity score and matching methods, which allowed us to emulate the design and results of an RCT. RESULTS: Among 3922 procedures, 1984 (51 %) patients underwent GA, of which 4.1 % experienced PONV, and 1938 underwent SA, of which 3.5 % experienced PONV. We found that the average treatment effect on the treated, i.e. the effect of anesthesia type for a sample of individuals that actually received spinal anesthesia compared to individuals who received GA, was ATET = 2.00 % [95 % CI, 0.78-3.19 %], which translated into an OR = 1.97 [95 % CI 1.35; 2.87]. CONCLUSION: This suggests that the type of anesthesia is not neutral regarding PONV, general anesthesia being more strongly associated with PONV than spinal anesthesia in orthopedic surgery

PaLI-X: On Scaling up a Multilingual Vision and Language Model

We present the training recipe and results of scaling up PaLI-X, a multilingual vision and language model, both in terms of size of the components and the breadth of its training task mixture. Our model achieves new levels of performance on a wide-range of varied and complex tasks, including multiple image-based captioning and question-answering tasks, image-based document understanding and few-shot (in-context) learning, as well as object detection, video question answering, and video captioning. PaLI-X advances the state-of-the-art on most vision-and-language benchmarks considered (25+ of them). Finally, we observe emerging capabilities, such as complex counting and multilingual object detection, tasks that are not explicitly in the training mix