Novel high-speed monolithic silicon detector for particle physics

This contribution presents simulation results, implementation, and first tests of a monolithic detector developed at KIT. It consists of a sensor diode tightly integrated with an analogue front-end based on SiGe (Silicon-Germanium) SG13G2 130 nm BiCMOS technology produced at the Leibniz Institute for High Performance Microelectronics (IHP). The pixel size is 100 μm × 100 μm, and the nwell charge collection node dimensions were reduced to 10 μm × 10 μm. We investigate the influence of this approach on sensor performance, spatial resolution via charge sharing and timing behaviour

Status of HVCMOS developments for ATLAS

This paper describes the status of the developments made by ATLAS HVCMOS and HVMAPS collaborations. We have proposed two HVCMOS sensor concepts for ATLAS pixels—the capacitive coupled pixel detector (CCPD) and the monolithic detector. The sensors have been implemented in three semiconductor processes AMS H18, AMS H35 and LFoundry LFA15. Efficiency of 99.7% after neutron irradiation to 1015 neq/cm2W has been measured with the small area CCPD prototype in AMS H18 technology. About 84% of the particles are detected with a time resolution better than 25 ns. The sensor was implemented on a low resistivity substrate. The large area demonstrator sensor in AMS H35 process has been designed, produced and successfully tested. The sensor has been produced on different high resistivity substrates ranging from 80 Ωcm to more than 1 kΩ. Monolithic- and hybrid readout are both possible. In August 2016, six different monolithic pixel matrices for ATLAS with a total area of 1 cm2 have been submitted in LFoundry LFA15 process. The matrices implement column drain and triggered readout as well as waveform sampling capability on pixel level. Design details will be presented

Factors Impacting Clinicians’ Adoption of a Clinical Photo Documentation App and its Implications for Clinical Workflows and Quality of Care: Qualitative Case Study

Background: Mobile health (mHealth) tools have shown promise in clinical photo and wound documentation for their potential to improve workflows, expand access to care, and improve the quality of patient care. However, some barriers to adoption persist. Objective: This study aims to understand the social, organizational, and technical factors affecting clinicians’ adoption of a clinical photo documentation mHealth app and its implications for clinical workflows and quality of care. Methods: A qualitative case study of a clinical photo and wound documentation app called imitoCam was conducted. The data were collected through 20 in-depth interviews with mHealth providers, clinicians, and medical informatics experts from 8 clinics and hospitals in Switzerland and Germany. Results: According to the study participants, the use of mHealth in clinical photo and wound documentation provides numerous benefits such as time-saving and efficacy, better patient safety and quality of care, enhanced data security and validation, and better accessibility. The clinical workflow may also improve when the app is a good fit, resulting in better collaboration and transparency, streamlined daily work, clinician empowerment, and improved quality of care. The findings included important factors that may contribute to or hinder adoption. Factors may be related to the material nature of the tool, such as the perceived usefulness, ease of use, interoperability, cost, or security of the app, or social aspects such as personal experience, attitudes, awareness, or culture. Organizational and policy barriers include the available clinical practice infrastructure, workload and resources, the complexity of decision making, training, and ambiguity or lack of regulations. User engagement in the development and implementation process is a vital contributor to the successful adoption of mHealth apps. Conclusions: The promising potential of mHealth in clinical photo and wound documentation is clear and may enhance clinical workflow and quality of care; however, the factors affecting adoption go beyond the technical features of the tool itself to embrace significant social and organizational elements. Technology providers, clinicians, and decision makers should work together to carefully address any barriers to improve adoption and harness the potential of these tools

Atlaspix3: A high voltage CMOS sensor chip designed for ATLAS Inner Tracker

ATLASpix3 is a 2 x 2 cm$^{2}$ high voltage CMOS sensor chip designed to meet the specifications of outer layers of ATLAS inner tracker. It is compatible with the hybrid pixel sensor ASIC RD53A in terms of electronic interface and geometry. ATLASpix3 is a depleted monolithic CMOS pixel detector which allows the construction of quad modules of the same size as that of hybrid sensors. The readout scheme can be externally configured as triggered or triggerless column drain readout. The hit information is transmitted through a 1.28 Gbit/s serial link. The interface is based on a single command input that is used for providing clock, trigger and configuration commands. This contribution summarizes the detector architecture with focus on the design of its readout circuitry. In addition, simulation results obtained using ReadOut Modelling Environment (ROME), that led to the design of the readout system are discussed

Change in Tetracene Polymorphism Facilitates Triplet Transfer in Singlet Fission-Sensitized Silicon Solar Cells

Singlet fission in tetracene generates two triplet excitons per absorbed photon. If these triplet excitons can be effectively transferred into silicon (Si) then additional photocurrent can be generated from photons above the bandgap of Si. This could alleviate the thermalization loss and increase the efficiency of conventional Si solar cells. Here we show that a change in the polymorphism of tetracene deposited on Si due to air exposure, facilitates triplet transfer from tetracene into Si. Magnetic field-dependent photocurrent measurements confirm that triplet excitons contribute to the photocurrent. The decay of tetracene delayed photoluminescence was used to determine a triplet transfer time of 215 ns and a maximum yield of triplet transfer into Si of ~50 %. Our study suggests that control over the morphology of tetracene during deposition will be of great importance to boost the triplet transfer yield further

Technical design of the phase I Mu3e experiment

The Mu3e experiment aims to find or exclude the lepton flavour violating decay at branching fractions above . A first phase of the experiment using an existing beamline at the Paul Scherrer Institute (PSI) is designed to reach a single event sensitivity of . We present an overview of all aspects of the technical design and expected performance of the phase I Mu3e detector. The high rate of up to muon decays per second and the low momenta of the decay electrons and positrons pose a unique set of challenges, which we tackle using an ultra thin tracking detector based on high-voltage monolithic active pixel sensors combined with scintillating fibres and tiles for precise timing measurements

The nature of singlet exciton fission in carotenoid aggregates.

Singlet exciton fission allows the fast and efficient generation of two spin triplet states from one photoexcited singlet. It has the potential to improve organic photovoltaics, enabling efficient coupling to the blue to ultraviolet region of the solar spectrum to capture the energy generally lost as waste heat. However, many questions remain about the underlying fission mechanism. The relation between intermolecular geometry and singlet fission rate and yield is poorly understood and remains one of the most significant barriers to the design of new singlet fission sensitizers. Here we explore the structure-property relationship and examine the mechanism of singlet fission in aggregates of astaxanthin, a small polyene. We isolate five distinct supramolecular structures of astaxanthin generated through self-assembly in solution. Each is capable of undergoing intermolecular singlet fission, with rates of triplet generation and annihilation that can be correlated with intermolecular coupling strength. In contrast with the conventional model of singlet fission in linear molecules, we demonstrate that no intermediate states are involved in the triplet formation: instead, singlet fission occurs directly from the initial 1B(u) photoexcited state on ultrafast time scales. This result demands a re-evaluation of current theories of polyene photophysics and highlights the robustness of carotenoid singlet fission.This work was supported by the EPSRC (UK) (EP/G060738/ 1), the European Community (LASERLAB-EUROPE, grant agreement no. 284464, EC’s Seventh Framework Programme; and Marie-Curie ITN-SUPERIOR, PITN-GA-2009-238177), and the Winton Programme for the Physics of Sustainability. G.C. acknowledges support by the European Research Council Advanced Grant STRATUS (ERC-2011-AdG No. 291198). J.C. acknowledges support by the Royal Society Dorothy Hodgkin Fellowship and The University of Sheffield’s Vice- Chancellor’s Fellowship scheme.This is the final published version. It was first made available by ACS at http://pubs.acs.org/doi/abs/10.1021/jacs.5b01130