Simulation System for the Wendelstein 7-X Safety Control System

The Wendelstein 7-X (W7-X) Safety Instrumented System (SIS) ensures personal safety and investment protection. The development and implementation of the SIS are based on the international safety standard for the process industry sector, IEC 61511. The SIS exhibits a distributed and hierarchical organized architecture consisting of a central Safety System (cSS) on the top and many local Safety Systems (lSS) at the bottom. Each technical component or diagnostic system potentially hazardous for the staff or for the device is equipped with an lSS. The cSS is part of the central control system of W7-X. Whereas the lSSs are responsible for the safety of each individual component, the cSS ensures safety of the whole W7-X device. For every operation phase of the W7-X experiment hard- and software updates for the SIS are mandatory. New components with additional lSS functionality and additional safety signals have to be integrated. Already established safety functions must be adapted and new safety functions have to be integrated into the cSS. Finally, the safety programs of the central and local safety systems have to be verified for every development stage and validated against the safety requirement specification. This contribution focuses on the application of a model based simulation system for the whole SIS of W7-X. A brief introduction into the development process of the SIS and its technical realization will be give followed by a description of the design and implementation of the SIS simulation system using the framework SIMIT (Siemens). Finally, first application experiences of this simulation system for the preparation of the SIS for the upcoming operation phase OP 1.2b of W7-X will be discussed

Access to HIV prevention and care for HIV-exposed and HIV-infected children : a qualitative study in rural and urban Mozambique

Background: Follow-up of HIV-exposed children for the delivery of prevention of mother-to-child transmission services and for early diagnosis and treatment of HIV infection is critical to their survival. Despite efforts, uptake of postnatal care for these children remains low in many sub-Saharan African countries. Methods: A qualitative study was conducted in three provinces in Mozambique to identify motivators and barriers to improve uptake of and retention in HIV prevention, care and treatment services for HIV-exposed and HIV-infected children. Participant recommendations were also gathered. Individual interviews (n = 79) and focus group discussions (n = 32) were conducted with parents/caregivers, grandmothers, community leaders and health care workers. Using a socioecological framework, the main themes identified were organized into multiple spheres of influence, specifically at the individual, interpersonal, institutional, community and policy levels. Results: Study participants reported factors such as seeking care outside of the conventional health system and disbelief in test results as barriers to use of HIV services. Other key barriers included fear of disclosure at the interpersonal level and poor patient flow and long waiting time at the institutional level. Key facilitators for accessing care included having hope for children's future, symptomatic illness in children, and the belief that health facilities were the appropriate places to get care. Conclusions: The results suggest that individual-level factors are critical drivers that influence the health-seeking behavior of caregivers of HIV-exposed and HIV-infected children in Mozambique. Noted strategies are to provide more information and awareness on the benefits of early pediatric testing and treatment with positive messages that incorporate success stories, to reach more pregnant women and mother-child pairs postpartum, and to provide counseling during tracing visits. Increasing uptake and retention may be achieved by improving patient flow at the institutional level at health facilities, by addressing concerns with family decision makers, and by working with community leaders to support the uptake of services for HIV-exposed children for essential preventive care

Upgrade of the Cold Electronics of the ATLAS HEC Calorimeter for sLHC

The signal amplification and summation electronics of the ATLAS Hadronic End-cap Calorimeter (HEC) is operated at the circumference of the HEC calorimeters inside the cryostats in liquid argon. The present electronics is designed to operate at irradiation levels expected for the LHC. For operation at the sLHC the irradiation levels are expected to be a factor 10 higher, therefore a new electronic system might be needed. The technological possibilities are investigated. From irradiation tests of the present HEC electronics it is known that it will operate up to a dose of 55 kGy of ionizing radiation and up to a neutron fluence of 3 * 10**14 n/cm**2, where it shows some degradation of performance. This matches well the requirements of up to 1.5 * 10**13 n/cm**2 for 10 years of LHC operation, including safety factors. For a subsequent sLHC running phase with 10 times higher expected irradiation levels, a more radiation hard HEC electronics will be needed. Therefore generic studies of different technologies have been carried out at the transistor level to understand the radiation hardness up to integrated neutron fluxes of ~2*10**16 n/cm**2 and the behaviour during operation at cryogenic temperatures. The S-parameter technique has been used to monitor the performance e.g. of gain and linearity during irradiation at room temperature. In addition, DC measurements before and after irradiation have been compared. Results of these tests and of accompanying noise tests are reported. In addition, results of S-parameter measurements will be reported operating the transistors in liquid nitrogen. Conclusions are drawn and the potential is assessed on the viability of using the tested technologies for carrying out the design of new HEC cold electronics for the sLHC