Abstract
The ALICE Inner Tracking System has been recently upgraded to a full silicon detector consisting entirely of monolithic active pixel sensors, arranged in seven concentric layers around the ...LHC beam pipe. Further ahead, during the LHC Long Shutdown 3, the ALICE collaboration is planning to replace the three innermost layers of this new ITS with a novel vertex detector. The proposed design features wafer-scale, ultra-thin, truly cylindrical MAPS. The new sensors will be thinned down to 20–40 µm, featuring a material budget of less than 0.05%
x
/
X
0
per layer, unprecedented low, and will be arranged concentrically around the beam pipe, as close as 18 mm from the interaction point.
Anticipating the first prototypes in the new 65 nm CMOS technology node, an active R&D programme is underway to test the response to bending of existing 50 µm thick ALPIDE sensors. A number of such chips were successfully bent, even below the targeted innermost radius, without signs of mechanical damage, while retaining their full electrical functionality in laboratory tests. The curved detectors were subsequently tested during particle beam campaigns, where their particle detection performance was assessed.
In this contribution, testbeam highlights from the data analysis of bent ALPIDE sensors, will be presented. It was proved that the current ALPIDE produced in the 180 nm CMOS technology retains its properties after bending. The results show an inefficiency that is generally below 10
−4
, independent of the inclination and position of the impinging beam with respect to the sensor surface. This encouraging outcome proves that the use of curved MAPS is an exciting possibility for future silicon detector designs, as not only the sensor can survive the bending exercise mechanically, but the enticing attributes that make it attractive for use in the inner tracking layers are comparable to the flat state.
Secondary discharge studies in single- and multi-GEM structures Deisting, A.; Garabatos, C.; Gasik, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2019, Letnik:
937
Journal Article
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Odprti dostop
Secondary discharges, which consist of the breakdown of a gap near a GEM foil upon a primary discharge across that GEM, are studied in this work.
Their main characteristics are the occurrence a few ...10μs after the primary, the relatively sharp onset at moderate electric fields across the gap, the absence of increased fields in the system, and their occurrence under both field directions.
They can be mitigated using series resistors in the high-voltage connection to the GEM electrode facing towards an anode. The electric field at which the onset of secondary discharges occurs indeed increases with increasing resistance. Discharge propagation from GEM to GEM in a multi-GEM system affects the occurrence probability of secondary discharges in the gaps between neighbouring GEMs.
Furthermore, evidence of charges flowing through the gap after the primary discharge are reported. Such currents may or may not lead to a secondary discharge. A characteristic charge, of the order of 1010 electrons, has been measured as the threshold for a primary discharge to be followed by a secondary discharge, and this number slightly depends on the gas composition. A mechanism involving the heating of the cathode surface as trigger for secondary discharges is proposed.
Abstract
The upgrade of the ALICE TPC will allow the experiment to cope with the high interaction rates foreseen for the forthcoming Run 3 and Run 4 at the CERN LHC. In this article, we describe the ...design of new readout chambers and front-end electronics, which are driven by the goals of the experiment. Gas Electron Multiplier (GEM) detectors arranged in stacks containing four GEMs each, and continuous readout electronics based on the SAMPA chip, an ALICE development, are replacing the previous elements. The construction of these new elements, together with their associated quality control procedures, is explained in detail. Finally, the readout chamber and front-end electronics cards replacement, together with the commissioning of the detector prior to installation in the experimental cavern, are presented. After a nine-year period of R&D, construction, and assembly, the upgrade of the TPC was completed in 2020.
Surgical treatment of breast cancer has been marked by a constant evolution since the Halsted radical mastectomy described in the late 19th century has become the current standard Madden radical ...mastectomy, a breast surgery that involves the ablation of tissue with the axillary lymphatic preserving both pectoral muscles. The purpose of this paper was to present the stages that have marked the evolution of this intervention and to provide an overview of the way breast cancer has been understood and treated in the last century.
Abstract
To operate the ALICE Time Projection Chamber in continuous mode during the Run 3 and Run 4 data-taking periods of the Large Hadron Collider, the multi-wire proportional chamber-based readout ...was replaced with gas-electron multipliers. As expected, the detector performance is affected by the so-called common-mode effect, which leads to significant baseline fluctuations. A detailed study of the pulse shape with the new readout has revealed that it is also affected by ion tails. Since reconstruction and data compression are performed fully online, these effects must be corrected at the hardware level in the FPGA-based common readout units. The characteristics of the common-mode effect and of the ion tail, as well as the algorithms developed for their online correction, are described in this paper. The common-mode dependencies are studied using machine-learning techniques. Toy Monte Carlo simulations are performed to illustrate the importance of online corrections and to investigate the performance of the developed algorithms.
Axillary lymph node evaluation remains essential in breast cancer surgery, first as a prognostic factor, because it indicates the degree of dissemination of the disease to the main lymphatic drainage ...basin of the breast, and, on the other hand, as an element of preventing the local relapse. In the era of the sentinel lymph node, complete axillary lymphadenectomy, considered valuable until recently, but as therapeutic and diagnostic, has become an intervention performed increasingly rare in selected cases. Axillary lymphatic tissue resections are accompanied by morbidity (lymphedema, paresthesia, limitations of arm movement) and symptom magnitude is proportional to the extension of the intervention. For this reason, a solution to avoid these kinds of complications was looked for. Since Gould, in 1960, who mentioned cancer parotid and continuing with Cabanas, Morton, or Veronesi, many surgeons have contributed to the development of safe techniques with which the multidisciplinary team involved in the surgical treatment for breast cancer could perform a safe oncological intervention and at the same time could conserve the healthy tissue, thus limiting morbidity. To achieve this standard, axillary lymphadenectomy has passed through several stages, from over radical interventions that followed the Halsted era, in which, besides axillary lymph nodes, the internal mammary and jugulo-carotidian lymph nodes were excised, to the absence of axillary surgery and replacing it with radiation therapy.
Secondary discharges, which consist of the breakdown of a gap near a GEM foil upon a primary discharge across that GEM, are studied in this work. Their main characteristics are the occurrence a few ...\(10\,\mu \textrm{s}\) after the primary, the relatively sharp onset at moderate electric fields across the gap, the absence of increased fields in the system, and their occurrence under both field directions. They can be mitigated using series resistors in the high-voltage connection to the GEM electrode facing towards an anode. The electric field at which the onset of secondary discharges occurs indeed increases with increasing resistance. Discharge propagation form GEM to GEM in a multi-GEM system affects the occurrence probability of secondary discharges in the gaps between neighbouring GEMs. Furthermore, evidence of charges flowing through the gap after the primary discharge are reported. Such currents may or may not lead to a secondary discharge. A characteristic charge, of the order of \(10^{10}\,\textrm{electrons}\), has been measured as the threshold for a primary discharge to be followed by a secondary discharge, and this number slightly depends on the gas composition. A mechanism involving the heating of the cathode surface as trigger for secondary discharges is proposed.
The aim of this study was to evaluate whether an intraoperative bronchospasm is more frequent in sinus surgery than in non-sinus surgery, whether its appearance after application of a non-steroidal ...anti-inflammatory drug (NSAID) is an indicator of an aspirin intolerance syndrome, and whether its appearance can be interpreted as an aspirin provocation test.
Anaesthesia charts from 5 years were retrospectively analysed whether anaphylactic/allergic reactions or bronchospasm were observed intraoperatively. In these cases the ENT charts of the patients were analysed and the occurrence of an analgesic-induced bronchospasm was assumed according to a probability algorithm.
All operations in general anaesthesia of an otorhinolaryngology clinic were analysed.
An intraoperative bronchospasm was observed significantly more often in patients undergoing sinus surgery than during other ENT operations. In 17 of 23 patients a possible/probable analgesic-induced bronchospasm after application of NSAID was found. Diclofenac was intraoperatively given in 3 patients, diclofenac and metamizole in 5 patients, metamizole in 7 patients, paracetamol in 1 patient, and paracetamol and metamizole in 1 patient.
An intraoperative bronchospasm during sinus surgery is not a clear indicator of an aspirin intolerance syndrome. An analgesic-induced bronchospasm can also be observed after paracetamol and metamizole. It can not be interpreted analogous to an aspirin provocation test.
In albino rats, infarctoid myocardial lesions were produced by intraperitoneal (i.p.) administration of isoproterenol (75 mg/kg, during 3 days). In other groups, the descending anterior left coronary ...artery was ligated. In both experimental settings, the intracerebroventricular (i.c.v.) administration of (+/-) propranolol (100-200-300 microg/animal/day, during 7 days) or (+/-) verapamil (40-80-160 microg/animal/day, during 7 days) afforded a significant protection (with the exception of the lowest dose) on the investigated parameters: arrhythmias, ischemic zone (in coronary ligated rats), lactate dehydrogenase and aspartate aminotransferase activity of the serum, focal necrosis (in isoproterenol treated rats). This protective activity is lower than that afforded by i.p. administered (+/-) propranolol (5 mg/kg, during seven days) or (+/-) verapamil (5 mg/kg, during seven days). From these data it may be concluded that (+/-) propranolol and (+/-) verapamil have a protective action on the experimental myocardial ischemia and necrosis in rats, not only when the drugs come in direct contact with the heart, but also acting upon the central nervous system.
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