Study of Ionization Charge Density-Induced Gain Suppression in LGADs

Gain suppression induced by excess carriers in Low Gain Avalanche Detectors (LGADs) has been investigated using 3 MeV protons in a nuclear microprobe. In order to modify the ionization density inside the detector, Ion Beam Induced Current (IBIC) measurements were performed at different proton beam incidence angles between 0◦ and 85◦. The experimental results have been analyzed as a function of the ionization density projected on the multiplication layer, finding that the increase of ionization density leads to greater gain suppression. For bias voltages close to the gain onset value, this decrease in gain results into a significant distortion of the transient current waveforms measured by the Time-Resolved IBIC (TRIBIC) technique due to a deficit in the secondary holes component. For angles of incidence such that the Bragg peak falls within the sensitive volume of the detector, the formation of microplasmas modifies the behavior of the gain curves, producing an abrupt decrease in gain as the angle increases.Ministerio de Ciencia, Innovación y Universidades RTI2018-098117-B-C21, 10.13039/501100011033, ICTS-2020-02-US-4Junta de Andalucía US-1380791European Union FPA2017-85155-C4-1-R, FPA2017-85155-C4-2-

Evolución paleogeográfica, paleoclimática y paleoambiental de la costa meridional de la Península Ibérica durante el Pleistoceno superior. El caso de la Cueva de Nerja (Málaga, Andalucía, España).

Presentamos los cambios paleogeográficos, paleoclimáticos y paleoambientales acontecidos en la costa mediterránea meridional de la Península Ibérica durante el Pleistoceno superior y comienzos del Holoceno, analizados a partir de la cartografía batimétrica y geomorfológica de la franja costera submarina del este de Málaga, del registro de la temperatura de la superficie del mar de Alborán obtenido en el sondeo MD95-2043 y de los datos radiométricos, paleobiológicos y arqueológicos proporcionados por el registro estratigráfico del yacimiento de la Cueva de Nerja (Nerja, Málaga, España). Este registro sedimentario, con doce etapas de erosión y sedimentación, se emplazó en las salas más exteriores de la cavidad entre los estadios finales del Pleistoceno superior y el Holoceno medio en un lapso cronológico comprendido entre 29600 y 3940 años cal BP. Durante ese tiempo, la posición del mar estuvo situada a diferentes cotas por debajo de su posición actual, lo que condicionó la emersión de una franja costera de diferente amplitud a lo largo del tiempo, en la que las poblaciones humanas que habitaron la Cueva de Nerja desarrollaron sus actividades. Igualmente se observa una notable variación en la temperatura superficial del agua del mar y una serie de cambios en la composición de la vegetación y la fauna de vertebrados e invertebrados explotadas por los habitantes de la Cueva de Nerja. En este contexto cabe señalar la presencia en el registro de la cavidad de diferentes especies marinas de latitudes septentrionales y aguas más frías, actualmente ajenas al Mediterráneo

The CMS Phase-1 pixel detector upgrade

CMS collaboration: et al.The CMS detector at the CERN LHC features a silicon pixel detector as its innermost subdetector. The original CMS pixel detector has been replaced with an upgraded pixel system (CMS Phase-1 pixel detector) in the extended year-end technical stop of the LHC in 2016/2017. The upgraded CMS pixel detector is designed to cope with the higher instantaneous luminosities that have been achieved by the LHC after the upgrades to the accelerator during the first long shutdown in 2013–2014. Compared to the original pixel detector, the upgraded detector has a better tracking performance and lower mass with four barrel layers and three endcap disks on each side to provide hit coverage up to an absolute value of pseudorapidity of 2.5. This paper describes the design and construction of the CMS Phase-1 pixel detector as well as its performance from commissioning to early operation in collision data-taking.The tracker groups gratefully acknowledge financial support from the following funding agencies: BMWFW and FWF (Austria); FNRS and FWO (Belgium); CERN; MSE and CSF (Croatia); Academy of Finland, MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); NKFIA K124850, and Bolyai Fellowship of the Hungarian Academy of Sciences (Hungary); DAE and DST (India); IPM (Iran); INFN (Italy); PAEC (Pakistan); SEIDI, CPAN, PCTI and FEDER (Spain); Swiss Funding Agencies (Switzerland); MST (Taipei); STFC (United Kingdom); DOE and NSF (U.S.A.). Individuals have received support from HFRI (Greece). The irradiation campaign has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement no. 654168.Peer reviewe

Experimental study of different silicon sensor options for the upgrade of the CMS Outer Tracker

CMS Collaboration: et al.During the high-luminosity phase of the LHC (HL-LHC), planned to start in 2027, the accelerator is expected to deliver an instantaneous peak luminosity of up to 7.5×1034 cm−2 s−1. A total integrated luminosity of 0300 or even 0400 fb−1 is foreseen to be delivered to the general purpose detectors ATLAS and CMS over a decade, thereby increasing the discovery potential of the LHC experiments significantly. The CMS detector will undergo a major upgrade for the HL-LHC, with entirely new tracking detectors consisting of an Outer Tracker and Inner Tracker. However, the new tracking system will be exposed to a significantly higher radiation than the current tracker, requiring new radiation-hard sensors. CMS initiated an extensive irradiation and measurement campaign starting in 2009 to systematically compare the properties of different silicon materials and design choices for the Outer Tracker sensors. Several test structures and sensors were designed and implemented on 18 different combinations of wafer materials, thicknesses, and production technologies. The devices were electrically characterized before and after irradiation with neutrons, and with protons of different energies, with fluences corresponding to those expected at different radii of the CMS Outer Tracker after 0300 fb−1. The tests performed include studies with β sources, lasers, and beam scans. This paper compares the performance of different options for the HL-LHC silicon sensors with a focus on silicon bulk material and thickness.The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project AIDA, grant agreement no. 262025.Peer reviewe

Occurrence of whale barnacles in Nerja Cave (Málaga, southern Spain): Indirect evidence of whale consumption by humans in the Upper Magdalenian

A total of 167 plates of two whale barnacle species (Tubicinella majorLamarck, 1802 and Cetopirus complanatusMörch, 1853) have been found in the Upper Magdalenian layers of Nerja Cave, Mina Chamber (Maro, Málaga, southern Spain). This is the first occurrence of these species in a prehistoric site. Both species are specific to the southern right whale Eubalena australis, today endemic in the Southern Hemisphere. Because of Antarctic sea-ice expansion during the Last Glacial Period, these whales could have migrated to the Northern Hemisphere, and reached southern Spain. Whale barnacles indicate that maritime-oriented forager human groups found stranded whales on the coast and, because of the size and weight of the large bones, transported only certain pieces (skin, blubber and meat) to the caves where they were consumed

Palaeolithic – Epipalaeolithic Seapeople of the Southern Iberian coast (Spain): an overview

The significance of coastal areas to human survival and expansion on the planet is undeniable. Their ecological diversity and their use as communication routes are some of their most distinctive qualities. However, the evidence of exploitation of these resources has had an uneven preservation, which is limited to certain regions and more recent events, mainly sites with deposits from the Upper Pleistocene and Holocene. This paper analyses the data available on the use of marine resources between MIS 6 and MIS 1 (c. 150 – 9 ka BP) in Southern Iberia, one of the first regions in Europe where marine faunal remains were discovered, in archaeological deposits from Middle and Upper Palaeolithic. Therefore their presence here has not been a criterion of separation between Neanderthals and Modern humans, but it may be relevant to analyze changes in the use of small preys or assess the economic diversification in regions where this came at an early date. One of the aims of this study was to evaluate the diachronic trends of the different palaeobiological marine remains recovered from coastal and inland archaeological sites. This preliminary extract indicates that the analysis of marine resource exploitation cannot be classed as a mere listing of palaeobiological remains. This information may be relevant in the initial stages, but it is insufficient in the evaluation of techno-economic and sociocultural transformations that can be linked to the use of marine resources. The distribution of palaeobiological marine remains differs over time and also according to the location of the sites with respect to the changing coastline throughout the period analysed. The known sites that preserve evidence of the use of marine resources as a food source are located mainly on the present coastline, or in a range of less than 10 km. Invertebrate remains have been identified in most, whereas fish, bird and mammal bones only in certain sites. Molluscs used as ornaments or pendants and containers are more widely distributed than other species used for food. Because these data must be contextualized, bone and stone tools linked to the exploitation of the marine environment have been added to the palaeobiological information, drawing inferences based on the analogy between both ethnologically and archaeologically documented tools. Symbolic expressions have also been studied, given the significant number of painted and engraved marine fauna depictions, specifically pisciforms and mammals, found in southern Iberia. Lastly, available molecular data has also been evaluated, from the results of isotope analysis on human remains. This combination of palaeobiological, techno-economic, graphic-symbolic and molecular data, allows a first assessment of the use of marine resources in the region

Selection of the silicon sensor thickness for the Phase-2 upgrade of the CMS Outer Tracker

Tracker group of the CMS collaboration: et al.During the operation of the CMS experiment at the High-Luminosity LHC the silicon sensors of the Phase-2 Outer Tracker will be exposed to radiation levels that could potentially deteriorate their performance. Previous studies had determined that planar float zone silicon with n-doped strips on a p-doped substrate was preferred over p-doped strips on an n-doped substrate. The last step in evaluating the optimal design for the mass production of about 200 m2 of silicon sensors was to compare sensors of baseline thickness (about 300 μm) to thinned sensors (about 240 μm), which promised several benefits at high radiation levels because of the higher electric fields at the same bias voltage. This study provides a direct comparison of these two thicknesses in terms of sensor characteristics as well as charge collection and hit efficiency for fluences up to 1.5 × 1015 neq/cm2. The measurement results demonstrate that sensors with about 300 μm thickness will ensure excellent tracking performance even at the highest considered fluence levels expected for the Phase-2 Outer Tracker.We acknowledge the funding of personnel involved in these studies by the Federal Ministry of Education and Research of Germany in the framework of the “FIS-Projekt - Fortführung des CMSExperiments zum Einsatz am HL-LHC: Verbesserung des Spurdetektors für das Phase-II-Upgrade des CMS-Experiments” as well as by the Karlsruhe School of Elementary Particle and Astroparticle Physics: Science and Technology (KSETA). The tracker groups gratefully acknowledge financial support from the following funding agencies: BMWFW and FWF (Austria); FNRS and FWO (Belgium); CERN; MSE and CSF (Croatia); Academy of Finland, MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); NKFIA K124850, and Bolyai Fellowship of the Hungarian Academy of Sciences (Hungary); DAE and DST (India); IPM (Iran); INFN (Italy); LAS (Lithuania); PAEC (Pakistan); SEIDI, CPAN, PCTI and FEDER (Spain); Swiss Funding Agencies (Switzerland); MST (Taipei); STFC (United Kingdom); DOE and NSF (U.S.A.). Individuals have received support from HFRI (Greece).Peer reviewe

Higher COVID-19 pneumonia risk associated with anti-IFN-α than with anti-IFN-ω auto-Abs in children

We found that 19 (10.4%) of 183 unvaccinated children hospitalized for COVID-19 pneumonia had autoantibodies (auto-Abs) neutralizing type I IFNs (IFN-alpha 2 in 10 patients: IFN-alpha 2 only in three, IFN-alpha 2 plus IFN-omega in five, and IFN-alpha 2, IFN-omega plus IFN-beta in two; IFN-omega only in nine patients). Seven children (3.8%) had Abs neutralizing at least 10 ng/ml of one IFN, whereas the other 12 (6.6%) had Abs neutralizing only 100 pg/ml. The auto-Abs neutralized both unglycosylated and glycosylated IFNs. We also detected auto-Abs neutralizing 100 pg/ml IFN-alpha 2 in 4 of 2,267 uninfected children (0.2%) and auto-Abs neutralizing IFN-omega in 45 children (2%). The odds ratios (ORs) for life-threatening COVID-19 pneumonia were, therefore, higher for auto-Abs neutralizing IFN-alpha 2 only (OR [95% CI] = 67.6 [5.7-9,196.6]) than for auto-Abs neutralizing IFN-. only (OR [95% CI] = 2.6 [1.2-5.3]). ORs were also higher for auto-Abs neutralizing high concentrations (OR [95% CI] = 12.9 [4.6-35.9]) than for those neutralizing low concentrations (OR [95% CI] = 5.5 [3.1-9.6]) of IFN-omega and/or IFN-alpha 2

Advanced silicon sensors for future collider experiments

RESUMEN: En este trabajo se ha llevado a cabo un estudio de nuevos sensores de silicio para su uso en futuros experimentos colisionadores de partículas. Por una parte, se ha evaluado el daño por radiación de diodos de silicio de diferentes tecnologías y espesores para su uso en el futuro calorímetro del experimento Compact Muon Solenoid en el CERN. Estos sensores fueron irradiados con neutrones hasta fluencias de 1.6E16 n/cm2. Principalmente se han hecho estudios del consumo de corriente, efectos sobre la capacidad, medidas de colección de carga con láser y fuente radioactiva y medidas de resolución temporal. Por otro lado, se ha estudiado la viabilidad de un nuevo prototipo de sensores de microtiras con electrodos resistivos sensibles en dos coordenadas. Estos sensores fueron propuestos como una posible solución a incorporar en uno de los detectores del futuro International Linear Collider. En este nuevo prototipo de sensores, se incorpora el método de división de carga resistiva a lo largo de las microtiras. Se realizaron caracterizaciones con fuente radioactiva y medidas de la resolución espacial en ambas coordenadas.ABSTRACT: In this work it has been carried out a study of new silicon sensors for future collider experiments. Firstly, it has been evaluated the radiation hardness of silicon diodes of different thicknesses and different technologies for the new calorimeter of the Compact Muon Solenoid experiment placed at CERN. These sensors were irradiated with neutrons up to a fluence of 1.6E16 n/cm2. Mainly, it has been done studies of power consumption and radiation damage, capacitance and thickness measurements, charge collection efficiency studies with laser, radioactive source characterization and timing performance studies. Secondly, a performance study of two-dimensional position sensitive microstrip sensor with resistive electrodes have been done. These sensors were proposed as a possible solution for one of the detector in the future International Linear Collider. These new sensors implement the resistive charge division method along the microstrips. Radioactive source characterization and measurements of the spacial resolution in both coordinates have been done

Low Gain Avalanche Detectors for 4-dimensional tracking applications in severe radiation environments

This paper aims to give an overview of the current status of this technology. The most interesting approaches for future 4-dimensional tracking applications based on the LGAD technology will be presented here. In addition, the latest results on the performance after irradiation of standard LGADs will be reviewed too