JRA3 Electromagnetic Calorimeter Technical Design Report

This report describes the design of the prototype for an Silicon Tungsten electromagnetic calorimeter with unprecedented high granularity to be operated in a detector at the International Linear Collider (ILC). The R&D for the prototype is co-funded by the European Union in the FP6 framework within the so called EUDET project in the years 2006-2010. The dimensions of the prototype are similar to those envisaged for the final detector. Already at this stage the prototype features a highly compact design. The sensitive layers, the Very Front End Electronics serving 64 channels per ASIC and copper plates for heat draining are integrated within 2000 μm

The LHCb Outer Tracker Front End Electronics

This note provides an overview of the front-end electronics used to readout the drift-times of the LHCb Outer Tracker straw tube chambers. The main functional components of the readout are the ASDBLR ASIC for amplification and signal digitization, the OTIS ASIC for the time measurement and for the L0 buffering, and the GOL ASIC to serialize the digital data for the optical data transmission. The L1 buffer board used to receive the data which is sent via the optical link is a common LHCb development and is not described here. This note supersedes an earlier document [1]

Climate geoengineering: issues of path-dependence and socio-technical lock-in

As academic and policy interest in climate geoengineering grows, the potential irreversibility of technological developments in this domain has been raised as a pressing concern. The literature on socio-technical lock-in and path dependence is illuminating in helping to situate current concerns about climate geoengineering and irreversibility in the context of academic understandings of historical socio-technical development and persistence. This literature provides a wealth of material illustrating the pervasiveness of positive feedbacks of various types (from the discursive to the material) leading to complex socio-technical entanglements which may resist change and become inflexible even in the light of evidence of negative impacts. With regard to climate geoengineering, there are concerns that geoengineering technologies might contribute so-called ‘carbon lock-in’, or become irreversibly ‘locked-in’ themselves. In particular, the scale of infrastructures that geoengineering interventions would require, and the issue of the so-called ‘termination effect’ have been discussed in these terms. Despite the emergent and somewhat ill-defined nature of the field, some authors also suggest that the extant framings of geoengineering in academic and policy literatures may already demonstrate features recognizable as forms of cognitive lock-in, likely to have profound implications for future developments in this area. While the concepts of path-dependence and lock-in are the subject of ongoing academic critique, by drawing analytical attention to these pervasive processes of positive feedback and entanglement, this literature is highly relevant to current debates around geoengineering

Stability and thermoelectric performance of doped higher manganese silicide materials solidi fied by RGS (ribbon growth on substrate) synthesis

Large scale deployment of thermoelectric devices requires that the thermoelectric materials have stable electrical, thermal and mechanical properties under the conditions of operation. In this study we examine the high temperature stability of higher manganese silicide (HMS) materials prepared by the RGS (ribbon growth on substrate) technique. In particular we characterize the effect of element substitution on the structural and electrical changes occurring at the hot side of temperatures of thermoelectric devices relevant to this material (600°C). Only by using suitable substitution (4% vanadium at the Mn site) can we obtain temperature-independent structural parameters in the range 20°C - 600°C, a condition that results in stable electrical properties. Additionally, we show that 4% vanadium substitution at the Mn site offers the best thermoelectric figure of merit among the different compositions reported here with ZTmax=0.52, a value comparable to the state of the art for HMS materials. Our analysis suggests that ionized impurity scattering is responsible for the better performance of this material