Development of fluorocarbon evaporative cooling recirculators and controls for the ATLAS inner silicon tracker

We report on the development of evaporative fluorocarbon cooling recirculators and their control systems for the ATLAS inner silicon tracker. We have developed a prototype circulator using a dry, hermetic compressor with C/sub 3/F/sup 8/ refrigerant, and have prototyped the remote-control analog pneumatic links for the regulation of coolant mass flows and operating temperatures that will be necessary in the magnetic field and radiation environment around ATLAS. pressure and flow measurement and control use 150+ channels of standard ATLAS LMB ("Local Monitor Board") DAQ and DACs on a multi-drop CAN network administered through a BridgeVIEW user interface. A hardwired thermal interlock system has been developed to cut power to individual silicon modules should their temperatures exceed safe values. Highly satisfactory performance of the circulator under steady state, partial-load and transient conditions was seen, with proportional fluid flow tuned to varying circuit power. Future developments, including a 6 kW demonstrator with ~25 cooling circuits, are outlined

Rethinking Radical Democracy

Over the course of three decades, vocabularies of radical democracy have pressed their stamp on democratic thought. Trading on the intuition that there is more to democracy than elections, they have generated critical insights into the important role that practices of pluralisation and critique play in bettering institutional politics. As a result, few would today deny the radical democratic contribution to democratic thought. What many might question, however, is its continuing traction. The paper probes this question, focusing on the nuanced place of democracy in contemporary radical work. It grapples with the difficulties that this poses for radical democrats and it suggests that a way of overcoming these difficulties – that threaten to undermine the coherence of radical democracy – is to rethink and reconstruct the distinctiveness of its vocabulary. The paper attempts such a reconstruction. It develops the idea of the promissory rule of the many and it discusses the ways it rejuvenates broader democratic thought

Fluorocarbon evaporative cooling developments for the ATLAS pixel and semiconductor tracking detectors

Heat transfer coefficients 2-5.103 Wm-2K-1 have been measured in a 3.6 mm I.D. heated tube dissipating 100 Watts - close to the full equivalent power (~110 W) of a barrel SCT detector "stave" - over a range of power dissipations and mass flows in the above fluids. Aspects of full-scale evaporative cooling circulator design for the ATLAS experiment are discussed, together with plans for future development

An Experimental Area for Short Baseline Neutrino Physics on the CERN Neutrino Beam to Gran Sasso

A new neutrino beam line from the CERN SPS to the Gran Sasso laboratory in Italy is presently under study. The new neutrino beam will allow both long baseline and short baseline neutrino oscillation experiments to be performed. This report presents a conceptual design of the short baseline experimental area to be located at a distance of 1858 m from the neutrino target

The COMPASS Experiment at CERN

The COMPASS experiment makes use of the CERN SPS high-intensitymuon and hadron beams for the investigation of the nucleon spin structure and the spectroscopy of hadrons. One or more outgoing particles are detected in coincidence with the incoming muon or hadron. A large polarized target inside a superconducting solenoid is used for the measurements with the muon beam. Outgoing particles are detected by a two-stage, large angle and large momentum range spectrometer. The setup is built using several types of tracking detectors, according to the expected incident rate, required space resolution and the solid angle to be covered. Particle identification is achieved using a RICH counter and both hadron and electromagnetic calorimeters. The setup has been successfully operated from 2002 onwards using a muon beam. Data with a hadron beam were also collected in 2004. This article describes the main features and performances of the spectrometer in 2004; a short summary of the 2006 upgrade is also given.Comment: 84 papes, 74 figure

Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics

A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN

Beyond the ontological turn: affirming the relative autonomy of politics

In this article, I critically evaluate a characteristic tendency that is found across the various traditions of poststructuralism, both narrowly and more broadly defined. This is an increasing propensity to be preoccupied with ontological questions and seemingly at the expense of either a refinement of political concepts or a concrete analysis of forms of power and domination. I consider the reasons for this development and stress how this characteristic feature of poststructuralism appears to follow from the very fact of ontological pluralism. What we see in contemporary continental thought is a proliferation of different traditions, and each side seeks to defend their position in ontological terms. Following this, I advance the idea of a relative autonomy between ontology and politics, where the former does not determine the latter in any direct or straightforward fashion. I argue that we need to stress this relative autonomy to open a little space between ontology and politics, space where we can return poststructuralism to a more concrete engagement with ‘the political’

CLOUD: an atmospheric research facility at CERN

This report is the second of two addenda to the CLOUD proposal at CERN (physics/0104048), which aims to test experimentally the existence a link between cosmic rays and cloud formation, and to understand the microphysical mechanism. The document places CLOUD in the framework of a CERN facility for atmospheric research, and provides further details on the particle beam requirements

Addendum to the CLOUD proposal

This report is the first of two addenda to the CLOUD proposal at CERN (physics/0104048), which aims to test experimentally the existence a link between cosmic rays and cloud formation, and to understand the microphysical mechanism. The document provides further details on the detector design, scientific motivation and experimental programme