Evaluation of planar silicon pixel sensors with the RD53A readout chip for the Phase-2 Upgrade of the CMS Inner Tracker

The Large Hadron Collider at CERN will undergo an upgrade in order to increase its luminosity to 7.5 × 10³⁴ cm⁻²s⁻¹. The increased luminosity during this High-Luminosity running phase, starting around 2029, means a higher rate of proton-proton interactions, hence a larger ionizing dose and particle fluence for the detectors. The current tracking system of the CMS experiment will be fully replaced in order to cope with the new operating conditions. Prototype planar pixel sensors for the CMS Inner Tracker with square 50 μm × 50 μm and rectangular 100 μm × 25 μm pixels read out by the RD53A chip were characterized in the lab and at the DESY-II testbeam facility in order to identify designs that meet the requirements of CMS during the High-Luminosity running phase. A spatial resolution of approximately 3.4 μm (2 μm) is obtained using the modules with 50 μm × 50 μm (100 μm × 25 μm) pixels at the optimal angle of incidence before irradiation. After irradiation to a 1 MeV neutron equivalent fluence of Φeq = 5.3 × 10¹⁵ cm⁻², a resolution of 9.4 μm is achieved at a bias voltage of 800 V using a module with 50 μm × 50 μm pixel size. All modules retain a hit efficiency in excess of 99% after irradiation to fluences up to 2.1 × 10¹⁶ cm⁻². Further studies of the electrical properties of the modules, especially crosstalk, are also presented in this paper

New vegetation type map of India prepared using satellite remote sensing: comparison with global vegetation maps and utilities

A seamless vegetation type map of India (scale 1: 50,000) prepared using medium-resolution IRS LISS-III images is presented. The map was created using an on-screen visual interpretation technique and has an accuracy of 90%, as assessed using 15,565 ground control points. India has hitherto been using potential vegetation/forest type map prepared by Champion and Seth in 1968. We characterized and mapped further the vegetation type distribution in the country in terms of occurrence and distribution, area occupancy, percentage of protected area (PA) covered by each vegetation type, range of elevation, mean annual temperature and precipitation over the past 100 years. A remote sensing-amenable hierarchical classification scheme that accommodates natural and semi-natural systems was conceptualized, and the natural vegetation was classified into forests, scrub/shrub lands and grasslands on the basis of extent of vegetation cover. We discuss the distribution and potential utility of the vegetation type map in a broad range of ecological, climatic and conservation applications from global, national and local perspectives. Weused 15,565 ground control points to assess the accuracy of products available globally (i.e., GlobCover, Holdridge’s life zone map and potential natural vegetation (PNV) maps). Hence we recommend that the map prepared herein be used widely. This vegetation type map is the most comprehensive one developed for India so far. It was prepared using 23.5m seasonal satellite remote sensing data, field samples and information relating to the biogeography, climate and soil. The digital map is now available through a web portal (http://bis.iirs.gov.in)

New vegetation type map of India prepared using satellite remote sensing: Comparison with global vegetation maps and utilities

International audienceA seamless vegetation type map of India (scale 1: 50,000) prepared using medium-resolution IRS LISS-III images is presented. The map was created using an on-screen visual interpretation technique and has an accuracy of 90%, as assessed using 15,565 ground control points. India has hitherto been using potential vegetation/forest type map prepared by Champion and Seth in 1968. We characterized and mapped further the vegetation type distribution in the country in terms of occurrence and distribution, area occupancy, percentage of protected area (PA) covered by each vegetation type, range of elevation, mean annual temperature and precipitation over the past 100 years. A remote sensing-amenable hierarchical classification scheme that accommodates natural and semi-natural systems was conceptualized, and the natural vegetation was classified into forests, scrub/shrub lands and grasslands on the basis of extent of vegetation cover. We discuss the distribution and potential utility of the vegetation type map in a broad range of ecological, climatic and conservation applications from global, national and local perspectives. We used 15,565 ground control points to assess the accuracy of products available globally (i.e., GlobCover, Holdridge’s life zone map and potential natural vegetation (PNV) maps). Hence we recommend that the map prepared herein be used widely. This vegetation type map is the most comprehensive one developed for India so far. It was prepared using 23.5 m seasonal satellite remote sensing data, field samples and information relating to the biogeography, climate and soil. The digital map is now available through a web portal (http://bis.iirs.gov.in)

Beam Test Performance Studies of CMS Phase-2 Outer Tracker Module Prototypes

International audienceA new tracking detector will be installed as part of the Phase-2 upgrade of the CMS detector for the high-luminosity LHC era. This tracking detector includes the Inner Tracker, equipped with silicon pixel sensor modules, and the Outer Tracker, consisting of modules with two parallel stacked silicon sensors. The Outer Tracker front-end ASICs will be able to correlate hits from charged particles in these two sensors to perform on-module discrimination of transverse momenta $p_\mathrm{T}$. The $p_\mathrm{T}$ information is generated at a frequency of 40 MHz and will be used in the Level-1 trigger decision of CMS. Prototypes of the so-called 2S modules were tested at the Test Beam Facility at DESY Hamburg between 2019 and 2020. These modules use the final front-end ASIC, the CMS Binary Chip (CBC), and for the first time the Concentrator Integrated Circuit (CIC), optical readout and on-module power conversion. In total, seven modules were tested, one of which was assembled with sensors irradiated with protons. An important aspect was to show that it is possible to read out modules synchronously. A cluster hit efficiency of about 99.75% was achieved for all modules. The CBC $p_\mathrm{T}$ discrimination mechanism has been verified to work together with the CIC and optical readout. The measured module performance meets the requirements for operation in the upgraded CMS tracking detector

Measurement of the fractional radiation length of a pixel module for the CMS Phase-2 upgrade via the multiple scattering of positrons

International audienceHigh-luminosity particle collider experiments such as the ones planned at the High-Luminosity Large Hadron Collider require ever-greater vertexing precision of the tracking detectors, necessitating also reductions in the material budget of the detectors. Traditionally, the fractional radiation length ($x/X_0$) of detectors is either estimated using known properties of the constituent materials, or measured in dedicated runs of the final detector. In this paper, we present a method of direct measurement of the material budget of a CMS prototype module designed for the Phase-2 upgrade of the CMS detector using a 40-65 MeV positron beam. A total of 630 million events were collected at the Paul Scherrer Institut PiE1 experimental area using a three-plane telescope consisting of the prototype module as the central plane, surrounded by two MALTA monolithic pixel detectors. Fractional radiation lengths were extracted from scattering angle distributions using the Highland approximation for multiple scattering. A statistical technique recovered runs suffering from trigger desynchronisation, and several corrections were introduced to compensate for local inefficiencies related to geometric and beam shape constraints. An overall average $x/X_0$ of (0.84 $\pm$ 0.10)% across the surveyed regions was measured, which is compatible with an empirical estimate of 0.825% computed from known material properties. Higher-granularity maps of the fractional radiation length were produced for both rectangular regions and regions of uniform material composition. The results bode well for the CMS Phase-2 upgrade modules, which will play a key role in the minimisation of the material budget of the upgraded detector

Beam test performance of a prototype module with Short Strip ASICs for the CMS HL-LHC tracker upgrade

International audienceThe Short Strip ASIC (SSA) is one of the four front-endchips designed for the upgrade of the CMS Outer Tracker for the HighLuminosity LHC. Together with the Macro-Pixel ASIC (MPA) it willinstrument modules containing a strip and a macro-pixel sensorstacked on top of each other. The SSA provides both full readout ofthe strip hit information when triggered, and, together with theMPA, correlated clusters called stubs from the two sensors for useby the CMS Level-1 (L1) trigger system. Results from the firstprototype module consisting of a sensor and two SSA chips arepresented. The prototype module has been characterized at theFermilab Test Beam Facility using a 120 GeV proton beam