CO2 Detector Cooling Projects - Outline and Tasks

1. - PH R&D WP 11: DETECTOR COOLING -Outline of Projects and Tasks • Future (CO2?) Cooling Plants • 1.1 Construction of a functional CO2 “Proto-0” at Cryolab • 1.2 Two-Phase flow in CO2: models and correlations • 1.3 Design and construction of a standardized complete “portable” 2kW (?) unit • 1.4 Process modeling and dynamic simulation • “On Detector” Thermal Management • 2.1 Materials for thermal contact • 2.2 Structural materials with high thermal conductivity • 2.3 Local cooling through Micro-channels • Leak Search and in-situ Repair • 3.1 From “leak rates” to “fluid loss” • 3.2 Leak repair methods • 4.New Instrumentation • 4.1 Optical fibre-based Relative Humidity sensors

2. Future (CO2?) Cooling Plants • 1.1 Construction of a functional CO2“Proto-0” at Cryolab START: Summer 2009 DURATION: ~ 2years • CMS contribution to the project (CMS Karlsruhe – Wim de Boer - through Hans Postema and Antti Onnela): immediate availability of: • LEWA Membrane pump mod LDC1, adapted for CO2 (36 l/h, 80 bar max discharge, 39 bar max suction); • SWEP INTERNATIONAL Compact Brazed Heat Exchanger; • TECNODELTA C6F14 5kW primary cooling unit. • These are the basic components to set-up a full recirculation system “à la LHCb VeLo” (tanks are still needed?). The task is indeed to be seen as the very first step of the so called WP#2 of the Detector Cooling Project. • The set-up will be installed IN THE CRYOLAB (meeting with Johan Bremer to define details of “who does what” planned at the end of this week). Cryolab apparently extremely ready to engage on this activity. Ian Godlewski (ATLAS) already involved, NIKEF (Bart Verlaat) in the loop through Hans Postema at the moment. EN/CV-DC will be actively involved. • Purpose of this “Proto-0”: • Testing in realistic situation the effects of long pipes with complex geometry and different heights; • Create direct experience of use, performance and problems of this kind of device for DT engineer and technicians; • Study in operation the most appropriate approach to integrated controls; • Provide knowledge of the dynamic behaviour of the components in the optic of Process Modeling and Dynamic Simulation; • Form a sound basis for the design of the desired “2 kW portable unit” • Request from ATLAS IBL to use it as a test set-up for validation of the CO2 cooling concepts on stave prototypes.

3. Future (CO2?) Cooling Plants • 1.2 Two-Phase flow in CO2: models and correlations START: Spring 2009 DURATION: 1÷2 years (?) • Extremely poor forecast possibility exists today for HIGH PRESSURE two-phase flows: even the most recent and successful 3-zone model proposed by Consolini and Thome, providing relatively good forecast (± 30%) for HTC of low pressure refrigerants, performs rather poorly on CO2 and other refrigerant at high pressure. Experimental data are missing, in particular in “mini-channels” One small blowing test set-up at PH-DT (Joao Noite) recently started providing interesting results for configurations of interest for the CMS PIX. Can be easily modified for other configuration and for a parametrical approach. Other institutes (SLAC, Aachen, Fermilab etc…) are moving on and producing useful information: the data obtained will be verified, collected and organized in a rational way. • CRYOLAB is available to conduct high precision measurements of correlations (Δp, HTC, CTF, etc…) for CO2 flow in “mini-channels” with the precision and reliability needed to people developing models and correlations. Cryolab has also started a collaboration with Esslingen University on measurements on longer, larger-diameter pipes. • Full availability (and direct scientific interest!) for a collaboration on more reliable forecasting methods from the EPFLLTCM (Prof John Thome). Preliminary expression of interest to work on tuned CFD models from Technicsche Universität München (Prof. Harald Klein) • List of partners of PH/DT (Joao Noite): • - CERN TE/CRG-CI (Cryolab) • EPFL LTCM (Laboratoire de Transfer de Chaleur et de Masse) • ?? TUM (Fakultät für Maschinenwessen Lehrstuhl für Anlangen- und Prozesstechnik) ?? • - Potentially all outside institutes working on CO2 cooling for SHLC upgrades

4. Future (CO2?) Cooling Plants • 1.3 Design and construction of a standardized complete “portable” 2kW (?) unit START: Autumn 2009 DURATION: ~ 1÷2 years (+ future developments) The request for the development of a standard CO2 cooling unit with a refrigerant power of the order of ~2kW first came from ATLAS TC, but is of interest also for the CMS PIX upgrade project. Based on the experienced gained at NIKEF and with the “Proto-0” built a Cryolab, a compact “stand alone” unit will be conceived. Performance specifications will be discussed with the interested users (experiment TC’s or PO’s, collaborating institutes), market surveys will be performed for the principal components and an integrated design will be proposed. The system controls – based on PVSS and UNICOS – will form and integral part of the project. The whole project is to a large extent coincident with the so-called WP#2 of the Detector Cooling Project, presently under discussion/definition. PH/DT is proposing to take the leading responsibility on this DCP Work Package List of partners of PH/DT (“Eng Staff 1”, “Eng Staff 2”, Jerome Daguin, Lucasz Zwalinski, Alexandre Moraux, Joao Noite): - CERN PH/…(experiments) - CERN EN/CV-DC - CERN EN/ICE - NIKEF - SLAC - FNAL…

5. Future (CO2?) Cooling Plants • 1.4 Process modeling and dynamic simulation START: August 2009 DURATION: 3 years (+ future developments) Following a very positive experience developed in EN/ICE with the techniques of process modeling and dynamic simulation applied to cryogenic plants, a PhD programme focusing on the application of these techniques on future detector cooling plants has been launched and will start on August 1st. The PhD will be performed in collaboration with the JIPSA Lab of the Université Joseph Fourier (Grenoble), under the scientific supervision of Dr. Emanuel Witrant and Paolo Petagna The first subject on which this methodology will be applied will be the study of the alternative C3F8 cooling plant for the ATLAS ID based on the concept of a thermo-siphon circuit under the direction of Michele Battistin (EN/CV-DC) in the context of the so-called WP#3 of the Detector Cooling Project, which is led by EN/CV-DC. The following step will be the build-up of a library of dynamical behaviour of components of interest for the future Co2 cooling systems based on the experience gained with “Proto-0” and with the design of the standard unit. List of partners of PH/DT (Alexandre Moraux, “Eng. Staff 1”, Lucasz Zwalinski): - CERN EN/CV-DC - CERN EN/ICE - JIPSA Lab (Université Joseph Fourier in Grenoble),

6. “On Detector” Thermal Management • 2.1 Materials for thermal contact START: September 2009 DURATION: long term (includes irradiation tests) • Many different “customized” solutions have been adopted in the LHC Trackers to solve the thermal contact problem for detector module cooling: this gave rise to a somehow “unknown” (and certainly uncontrolled) presence of doped or modified materials in critical regions. It is both needed to: • Catalogue as much as possible the different solutions adopted and thoroughly test, in particularly against irradiation; • Provide a systematic (database) thermal, chemical and irradiation study of available compounds for future applications (doping agents for resins or silicones; thermal pastes; liquid metals; new exotic adhesives; etc). • Direct synergy with PH R&D WP7 is being organized (see Mar’s presentation). Strong interest for collaboration declared by Paolo Chiggiato (TE/VSC) for chemical analyses, production of materials and samples. Preliminary contacts established with Michele Giordano (CNR Napoli) for exotic adhesives and new doping agents (e.g. Carbon Nano-Tubes) and from Marco Fossa(University of Genova) for support on equipment for correct thermal measurements. Availability to access expertise given by Bruno Michel of the IBM Research Laboratory in Zurich. • List of partners of PH/DT (Paolo Petagna, Marc Tavlet, Jerome Daguin): • - CERN TE/VSC (CSA and CST) • CNR Napoli (Istituto per I MaterialiCompositi e Biomedici) • UniversitàdiGenova - DITEC (DIpartimentodiTermo-Energetica e Condizionamentoambientale) • Possibly some collaboration with IBM Research GmbH (Zurich) • potentially ALL institutes that participated in the construction of LHC Trackers

7. “On Detector” Thermal Management • 2.2 Structural materials with high thermal conductivity START: July 2009 DURATION: long term (includes irradiation tests) • Highly thermally conductive structural materials (High k CFRP, TPG, thermal foams, etc) find large application in “on-detector” thermal management to provide thermal bridges from heat source to heat sink. It is both needed to: • Catalogue as much as possible the materials used in the existing Tracker and whenever needed, re-test them particularly against irradiation; • Provide a systematic (database) thermal, mechanical and irradiation study of available materials for future applications (doping agents for resins or silicones; thermal pastes; liquid metals; new exotic adhesives; etc). • Direct synergy with PH R&D WP7 is being organized (see Mar’s presentation). Collaboration with Stefano Sgobba(EN/MME-MM) for mechanical tests is being discussed. Preliminary contacts established with Michele Giordano (CNR Napoli) for emerging materials (e.g. CNT in structural matrix) and from Marco Fossa (University of Genova) for support on equipment for correct thermal measurements. Some outside institutes have long-term detailed experience of use of specific material (e.g. FNAL made extensive use of TPG in the past): collaboration and information exchange will be looked for. • List of partners of PH/DT (Marc Tavlet, Paolo Petagna): • - CERN EN/MME-MM • CNR Napoli (Istituto per I MaterialiCompositi e Biomedici) • UniversitàdiGenova - DITEC (DIpartimentodiTermo-Energetica e Condizionamentoambientale) • FNAL and other institutes participating in the mechanical design of SLHC Tracker Upgrades

8. “On Detector” Thermal Management • 2.3 Local cooling through Micro-channels START: June 2009 DURATION: long term • Techniques of direct cooling of the chip through a coupled micro-channel circulation plate are presently studied for industrial microelectronics applications. Although the typical power densities for Tracking detectors and for these application are roughly two orders of magnitude apart (2-3 W/cm2 vs. 150-200 W/cm2), these techniques can potentially provide a very efficient and uniform cooling with an extremely reduced mass. • A first case-study for the application of this concept comes from the NA62 “GIGA-TRACKER”. In collaboration with Alex Kluge (PH/ESE) and Georg Nuessle (Université de Louvain) contacts established with two EPFL labs (LTCM, Prof John Thome, and LMSI4, Prof Philippe Renaudand Alessandro Mapelli) and with the IBM Research Laboratory in Zurich (Dr. Bruno Michel and Dr. YassirMadour). Formalization of the collaboration planned for June. Objective: • Proof of feasibility of a 20x60 mm,100 mm thick silicon heat sink with 50x50 mm channel cross-section: around end 2009; • Final resolution of technical problems (suited glass gluing, pipe connections, etc) and final production during 2010; • Long-term study of applicability to larger scale silicon tracking devices in parallel. • List of partners of PH/DT (Paolo Petagna, Jerome Daguin): • - CERN PH/ESE • Université de Louvain • EPFL LTCM (Laboratoire de Transfer de Chaleur et de Masse) • EPFL LMSI4 (Laboratoire de Micro-Sistemes 4) • IBM Research GmbH, Zurich Research Laboratory

9. Leak Search and in-situ Repair • 3.1 From “leak rates” to “fluid loss” START: June 2009 DURATION: ~ 6÷12 months • The definition of standardized leak finding techniques; the definition of methodologies for reliable and precise pressure decays; the quantification of a measured gas leak rate into a reliable estimate of fluid loss in different conditions; are all issues that proved to require further and more systematic work during the commissioning phase of the LHC Trackers. • This task is to a large extent coincident with the chapter “Acceptance criteria – Leak detection” of the proposed WP#4 of the Detector Cooling Project, presently under discussion/definition. Strong interest for collaboration declared by Paolo Chiggiato (TE/VSC). Objective: • Agreement on standard methods/means for leak detection and measurement; • Systematic analysis and classification of existing literature on the subject; • Design of a test bench and execution of ad-hoc tests on calibrated leaks on particular configurations of interest. • List of partners of PH/DT (“Eng Staff 2”): • CERN EN/CV-DC • TE/VSC

10. Leak Search and in-situ Repair • 3.2 Leak repair methods START: June 2009 DURATION: ~ largely dependent on first outcomes • Several methods for in-situ leak repair have been preliminarily scrutinized at RAL (Chemical solidification, Plating, Mineral suspensions, Epoxy emulsions, Silicate salts, etc). A few have shown promising potentialities for application to existing Tracking devices. Complete studies – from deep chemical understanding to test application on full scale mock-ups – are needed and RAL is not in condition to continue the study. ATLAS has first proposed this task to PH/DT and CMS has subsequently supported the request to be transformed into a task of common interest. • This task is coincident with the so-called WP#4 of the Detector Cooling Project, presently under discussion/definition. The starting information is to be provided by Jason Tarrant (RAL), who started the investigation. Strong interest for collaboration declared by Paolo Chiggiato (TE/VSC). A systematic irradiation programme on possible successful repair solution will be organized in synergy with PH R&D WP7. Objective: • Prosecution of the analysis of existing methodologies of leak repair; • Deep understanding of chemical implications of the different techniques (including – e.g. – needs for subsequent cleaning; • Construction of a test bench (real-scale mock-up of typical non accessible circuits) and execution of ad-hoc tests on calibrated leaks for the technique(s) possibly selected. • List of partners of PH/DT (Marc Tavlet, Paolo Petagna, “Eng Staff 2”): • RAL • CERN EN/CV-DC • TE/VSC

11. 4.New Instrumentation 4.1 Optical fibre-based Relative Humidity sensors START: Summer 2009 DURATION: ~ 2 years (?) • The availability of a miniaturized, long-term reliable, radiation resistant sensor of Relative Humidity to be used in the Tracking volume is still an issue today. Beside the work on the development of a new analog device in progress in CMS (Andromachi Tsirou, Piero Giorgio Verdini and Panagiotis Sarafis) a completely new class of physical sensors – based on light transmission - is possibly applicable also to the case of Relative Humidity. • Direct contacts have been established with CNR Napoli (Dr. Michele Giordano), the OptoelectronicDivision at the Dipartimento di Ingegneria of the Università del Sannio (Dr. Antonello Cutolo and Dr. Andrea Cusano), the Dipartimento di Ingegneria Biomedica, Elettronica e delle Telecomunicazioni of the Università di Napoli Federico II (Prof. Giovanni Breglio) and the INFN, sezione di Napoli (Dr. Salvatore Buontempo). The adaptationofexistingmeasurementsystems/devices – presentlyspecializedfor temperature and strain – tospecificmaterialsdevelopingcontrollable light scattering under varyinghumidityconditionswillbestudied. A protocolofcollaborationis in the processofdefinition. • List of partners of PH/DT (Paolo Petagna): • - CNR Napoli (Istituto per I MaterialiCompositi e Biomedici) • Università del Sannio (Optoelectronic Division) • Universitadi Napoli Federico II (Dipartimento di Ingegneria Biomedica, Elettronica e delle Telecomunicazioni) • INFN, Sezione di Napoli