MALTA2 is a depleted monolithic active pixel sensor (DMAPS) developed in the Tower 180 nm CMOS imaging process. Monolithic CMOS sensors offer advantages over current hybrid imaging sensors both in ...terms of increased tracking performance due to lower material budget but also in terms of ease of integration and construction costs due to the monolithic design. Current research and development efforts are aimed towards radiation-hard designs up to 100 Mrad in Total Ionizing Dose and 3×1015 1 MeV neq/cm2 in Non-Ionizing Energy Loss. One important property of a sensor’s radiation hardness is the depletion depth at which efficient charge collection is achieved via drift movement. Grazing angle test-beam data was taken during the 2023 SPS CERN test beam with the MALTA telescope and Edge Transient Current Technique studies were performed at DESY in order to develop a quantitative study of the depletion depth for un-irradiated, epitaxial MALTA2 samples. The study is planned to be extended for irradiated and Czochralski MALTA2 samples.
The DECAL sensor is a depleted monolithic active pixel sensor (DMAPS) being developed to explore technological solutions for digital electromagnetic calorimeters. For this application, the number of ...pixels above threshold is used to estimate the shower energy and therefore the pixel size is required to be sufficiently small to avoid hit saturation. The DECAL and DECAL Fully Depleted (FD) sensors have been designed and fabricated in the TowerJazz 180 nm CMOS standard and modified imaging processes, respectively. The latter uses modifications to the implant configuration that improve charge collection and radiation hardness, including to the levels required for barrel ECAL regions of FCC-hh (few 1015 neq/cm2). Both DECAL variants feature a matrix of 64 × 64 pixels with a pitch of 55μm, read out every 25 ns. For DECAL FD, the logic has been modified to extend the in-pixel comparator threshold trim range from five to six bits, with the sixth bit used to de-activate the comparator. Characterisation results for the DECAL FD, including the pixel equalisation matrix, threshold scans testing under monochromatic X-rays and 90Sr source, are presented.
Fate and transport of nitrogen (N) in urban coastal watersheds continues to draw research interest due to serious impacts of N pollution and complexities with N sources and transport pathways. In ...this study, we used multiple tracers for source identification of N pollution (15N isotope in nitrate and chemical sewage tracers in water) and waters (using isotopes of 18O and 2H in water) in a coastal northwest Florida U.S.A. urban bayou fed by two contrasting streams, namely Jackson Creek traversing a dense residential area and Jones Creek flowing mainly through a wetland preserve. Results showed that the slightly higher δ15N-NO3− values in Jones Creek and the bayou were insufficient to distinguish N sources; yet the different chemical sewage tracer concentrations (e.g., sucralose, carbamazepine and sulfamethoxazole) clearly demonstrated the major N source from leaking septic tanks in the Jackson Creek sub-basin but not in the Jones Creek sub-basin. The higher concentrations of nitrate, which constituted over 98% of dissolved inorganic N in Jackson Creek, support active nitrification in sandy soils and steep terrain while higher δ15N-NO3− and much lower nitrate in Jones Creek are likely associated with denitrification in dense vegetative wetland and riparian zones. Episodic high nitrate concentrations and δ18O values in Jackson Creek preceded by periods of little rainfall indicated that the creek was sustained by subsurface flow with a steady input of nitrate. This study demonstrated the connection of land use and stormwater runoff generation to the forms of N entering urban waterways, the utility of N sourcing approaches, and the value of watershed-scale assessments for developing strategies to limit N loadings in urban settings.
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•Urban creek nitrogen levels and speciation reflect basin land use.•Sewage tracers were more useful 15N isotopes for assessing septic N pollution.•High creek water nitrate was sourced to leaking septic tanks via subsurface flow.•Creekside vegetation and a natural preserve in creek headwaters benefit N levels.
