9 research outputs found
Etude des Ă©changes thermiques et conception dâun systĂšme de refroidissement pour le systĂšme de lecture du trajectographe SciFi de LHCb
In the context of the evolution of the biggest circular accelerator of particles «LHC», an important program of upgrade on all the detectors which establishes itself was thrown. Among them, we find the upgrade of the detector LHCb which includes the complete replacement of several sub-detectors. The frequency of high reading of 40MHz, an unprecedented in an experiment of physical appearance of particles, and the environment of severe radiation bound to the increase of the intensity of the LHC, are the main challenges by the new sub-detectors. The work presented in this manuscript, described as a small part of the evolution of the LHCb detector. The development and the construction of a new wide-scale tracker, based on a new technology with scintillating fiber «SciFi», read with photomultipliers to the silicon «SiPM», is one of the key projects of the LHCb upgrade program. The first part, consists in studying the thermal exchanges and designing a cooling system for every Read-Out Box «ROB» which contains two electronic front-end « FE », and which allow to read the data of the detector. The latter has a thermal dissipation about 110W. To ensure the smooth running of electronic components, it is compulsory to set up a cooler. Important constraints are taken into account in this study, the first one represents the space limited compared to the need for the cooling system, the electronic interfaces and mechanical, the second concerns the SiPM. Connected with the electronics by flexible cables, they are located near the electronics «FE» and their temperature of operation is perfectly settled around -40 ° C. Works of digital simulations on the software FloTHERM and ANSYS were led on the experimental bench realized within the laboratory, and which allowed us to determine the best adapted solution of cooling. This study also showed to us that he is more than necessity to integrate thermal interfaces «IT» such as thermal pastas to assure a better transfer of heat between electronic components and cooler. The second part, represents an in-depth study on the thermal interfaces which are a delicate point of transfer of heat, because they can have dozens percent of the global thermal resistance. To guarantee an adequate and sustainable use of these materials, several parameters were verified, in particular hardness, consistency (no production of fat or oil) and the thermal conductivity, thanks to a bench of measures adapted according to the method normalized ASTM D5470, with this bench we could measure the flow of heat through the tested thermal interface sample and which is generated by a hot source and a cold source that are mounted at the ends of our bench.With the installation CHARME (CERN) and PAVIRMA (CĂ©zeaux), a series of measure of irradiations at the neutrons and the X-rays are also made, correspond-ing to the environment in which they will be exposed in the experience, on one side to identify the damages and the possible changes on the thermal resistances by the analysis of the thermal impedance, the other one to identify the thermal interface which suits best our application and which allows to assure an excellent thermal exchange and thus a good cooling of the frontal electronics within the trajectographe of the detector LHCb.Dans le cadre de lâĂ©volution du plus grand accĂ©lĂ©rateur circulaire de particules « LHC », un important programme de mise Ă niveau sur lâensemble des dĂ©tecteurs qui le constitue a Ă©tĂ© lancĂ©. Parmi eux, on retrouve la mise Ă niveau du dĂ©tecteur LHCb qui comprend le remplacement complet de plusieurs sous-dĂ©tecteurs. La frĂ©quence de lecture Ă©levĂ©e de 40MHz, sans prĂ©cĂ©dent dans une expĂ©rience de physique des particules, et lâenvironnement de rayonnement sĂ©vĂšre liĂ© Ă lâaugmentation de lâintensitĂ© du LHC, sont les principaux dĂ©fis Ă relever par les nouveaux sous-dĂ©tecteurs. Le travail prĂ©sentĂ© dans ce manuscrit, dĂ©crit une petite partie de lâĂ©volution du dĂ©tecteur LHCb. Le dĂ©veloppement et la construction dâun nouveau trajectographe Ă grande Ă©chelle, basĂ© sur une nouvelle technologie Ă fibres scintillantes «SciFi», lues avec des photomultiplicateurs au silicium «SiPM», est lâun des projets clĂ©s du programme de mise Ă niveau de LHCb. La premiĂšre partie, consiste Ă Ă©tudier les Ă©changes thermiques et Ă concevoir un systĂšme de refroidissement pour chaque Read-Out Box « ROB » qui contient deux cartes Ă©lectroniques frontales « FE », et qui permettent de lire les donnĂ©es du dĂ©tecteur. Ces derniĂšres possĂšdent une dissipation thermique dâenviron 110W.Pour assurer le bon fonctionnement des composants Ă©lectroniques, il est obligatoire de mettre en place un refroidisseur. Des contraintes importantes sont prisent en compte dans cette Ă©tude, la premiĂšre reprĂ©sente lâespace limitĂ© en regard du besoin du systĂšme de refroidissement, des interfaces Ă©lectroniques et mĂ©canique, la seconde concerne les SiPM. ReliĂ©s Ă lâĂ©lectronique par des cĂąbles flexibles, elles sont situĂ©es Ă proximitĂ© de lâĂ©lectronique « FE » et leur tempĂ©rature de fonctionnement doit ĂȘtre parfaitement rĂ©glĂ©e autour des -40°C. Des travaux de simulations numĂ©riques sur les logiciels FloTHERM et ANSYS ont Ă©tĂ© menĂ©s sur le banc expĂ©rimental rĂ©alisĂ© au sein du laboratoire, et qui nous ont permis de dĂ©terminer la solution de refroidissement la mieux adaptĂ©e. Cette Ă©tude nous a aussi montrĂ© quâil est plus que nĂ©cessaire dâintĂ©grer des interfaces thermiques « IT» telles que des pĂątes thermiques afin dâassurer un meilleur transfert de chaleur entre les composants Ă©lectroniques et le refroidisseur. La deuxiĂšme partie, reprĂ©sente une Ă©tude approfondie sur les interfaces thermiques qui sont un point dĂ©licat de transfert de chaleur, car elles peuvent avoir plusieurs dizaines de pour cent de la rĂ©sistance thermique globale. Pour garantir une utilisation adĂ©quate et durable de ces matĂ©riaux, plusieurs paramĂštres ont Ă©tĂ© vĂ©rifiĂ©s, en particulier la duretĂ©, la consistance (pas de production de graisse ou dâhuile) et la conductivitĂ© thermique, grĂące Ă un banc de mesures adaptĂ© dâaprĂšs la mĂ©thode normalisĂ© ASTM D5470, grĂące auquel on a pu mesurer le flux de chaleur qui traverse lâĂ©chantillon dâinterface thermique testĂ© et qui est gĂ©nĂ©rĂ© par une source chaude et un source froide qui sont montĂ©es aux extrĂ©mitĂ©s de notre banc.GrĂące Ă lâinstallation CHARME (CERN) et Ă la plate-forme PAVIRMA (Campus des CĂ©zeaux), une sĂ©rie de mesure dâirradiations aux neutrons et aux rayons X sont Ă©galement effectuĂ©es, correspondant Ă lâenvironnement dans lequel elles seront exposĂ©es dans lâexpĂ©rience, dâun cĂŽtĂ© pour identifier les dĂ©gradations et changements possibles sur les rĂ©sistances thermiques par lâanalyse de lâimpĂ©dance thermique, de lâautre pour identifier lâinterface thermique qui convient le mieux Ă notre application et qui permet dâassurer un excellent Ă©change thermique et donc un bon refroidissement de lâĂ©lectronique frontale au sein du trajectographe du dĂ©tecteur LHCb
Thermal study and design of a cooling system for the electronics boards of the LHCb SciFi tracker
The LHCb detector, one of the four large LHC detectors, has launched a major upgrade program with the goal to enormously boost the rate and selectivity of the data taking. The LHCb upgrade comprises the complete replacement of several sub-detectors, the substantial upgrade of the front-end electronics and the introduction of a new paradigm, namely the suppression of a hardware trigger by reading out the whole experiment synchronously at a rate of 40 MHz. The high readout frequency, unprecedented in a particle physics experiment, and the harsh radiation environment related to the increased LHC intensity, are the major challenges to be addressed by the new sub-detectors. The development and construction of a new large-scale tracking detector, based on a novel scintillating fibre (SciFi) technology, read out with silicon photomultipliers (SiPM), is one of the key projects of the LHCb upgrade program. The LHCb SciFi detector will count more than 500,000 channels. It is composed of 12 layers arranged in 3 tracking stations each with 4 planes of scintillating fiber modules and with a total sensitive area of about 340 m2. It is necessary to design an on-detector electronics allowing to readout the detector at 40MHz and to transmit the data at this frequency to the data acquisition system. The most challenging part for the FE electronics is the signal digitisation. A new front-end ASIC with 128 channels, the number of channels of a SiPM, is being developed to process and digitise the analogue signal from the SiPM. The hit position of the particle needs to be computed with a spatial resolution less than 100 Όm. Four functions will be required to achieve this: amplification, shaping, integrating and digitisation. The boards hosting the ASIC and the clustering FPGAs, including the customised FPGA firmware are under design. Two front-end boards are used to read out half a SciFi module made of 2.5 m long fibre mats and are host in a Read Out Box (ROB). The power consumption of the boards in a ROB is around 120 W. In order to ensure the proper functioning of electronic components, it is mandatory to design a compact and efficient cooling system. It is worthwhile to notice that SiPM, which are connected to the electronics via flex cables, are located in the vicinity and their operating temperature must be regulated perfectly around -40° C. The first step to design the electronics cooling is to evaluate the energy balance of the electronic boards and to study the different cooling systems that may be appropriate. Once the modeling is done, the model is simulated with the FloTHERM and ANSYS softwares to find the more appropriate solution. The cooling system will be based on a demineralized water cooling system already existing in the LHCb cavern, but which will have to be redesigned to cope with the higher power consumption of the electronics, working at 19°C. Pipes going along the detector and through cooling blocks in Al or Cu will serve 5 or 6 ROB depending on the location. The electronic boards will be mounted on a radiator in Al which is screwed to two cooling blocks. The study of the cooling system has shown that it is more than necessary to integrate thermal interfaces such as thermal pastes in order to ensure a better thermal conductivity between the electronic components and the cooler. These interfaces are a delicate point of heat transfer because they can have several tens of percent of the overall thermal resistance. They therefore require a thorough knowledge of their behavior at thermal stresses, as well as their exposure to neutron and other radiation in which they will be surrounded during the operation of the experiment. In order to guarantee an adequate and durable use of these materials, several parameters have to be checked, in particular the hardness, the consistency (no grease or oil production) and the thermal conductivity. Thermal and radiation tests are therefore necessary in order to verify the resistance of the materials over the total duration considered for the detector, as well as hardness and thermal conductivity. Thermal conductivity measurement is an important and complicated part of the process. The appropriate method for measuring the thermal conductivity or thermal resistance of the interface material is based on ASTM D5470. A dedicated setup has been designed to perform these measurements. Prototypes of the different parts of the cooling system and of the electronics have been designed and built. Several tests have been conducted and the performances achieved will be presented
Study of thermal exchanges and design of a cooling system for the LHCb SciFi tracker reading system
Dans le cadre de lâĂ©volution du plus grand accĂ©lĂ©rateur circulaire de particules « LHC », un important programme de mise Ă niveau sur lâensemble des dĂ©tecteurs qui le constitue a Ă©tĂ© lancĂ©. Parmi eux, on retrouve la mise Ă niveau du dĂ©tecteur LHCb qui comprend le remplacement complet de plusieurs sous-dĂ©tecteurs. La frĂ©quence de lecture Ă©levĂ©e de 40MHz, sans prĂ©cĂ©dent dans une expĂ©rience de physique des particules, et lâenvironnement de rayonnement sĂ©vĂšre liĂ© Ă lâaugmentation de lâintensitĂ© du LHC, sont les principaux dĂ©fis Ă relever par les nouveaux sous-dĂ©tecteurs. Le travail prĂ©sentĂ© dans ce manuscrit, dĂ©crit une petite partie de lâĂ©volution du dĂ©tecteur LHCb. Le dĂ©veloppement et la construction dâun nouveau trajectographe Ă grande Ă©chelle, basĂ© sur une nouvelle technologie Ă fibres scintillantes «SciFi», lues avec des photomultiplicateurs au silicium «SiPM», est lâun des projets clĂ©s du programme de mise Ă niveau de LHCb. La premiĂšre partie, consiste Ă Ă©tudier les Ă©changes thermiques et Ă concevoir un systĂšme de refroidissement pour chaque Read-Out Box « ROB » qui contient deux cartes Ă©lectroniques frontales « FE », et qui permettent de lire les donnĂ©es du dĂ©tecteur. Ces derniĂšres possĂšdent une dissipation thermique dâenviron 110W.Pour assurer le bon fonctionnement des composants Ă©lectroniques, il est obligatoire de mettre en place un refroidisseur. Des contraintes importantes sont prisent en compte dans cette Ă©tude, la premiĂšre reprĂ©sente lâespace limitĂ© en regard du besoin du systĂšme de refroidissement, des interfaces Ă©lectroniques et mĂ©canique, la seconde concerne les SiPM. ReliĂ©s Ă lâĂ©lectronique par des cĂąbles flexibles, elles sont situĂ©es Ă proximitĂ© de lâĂ©lectronique « FE » et leur tempĂ©rature de fonctionnement doit ĂȘtre parfaitement rĂ©glĂ©e autour des -40°C. Des travaux de simulations numĂ©riques sur les logiciels FloTHERM et ANSYS ont Ă©tĂ© menĂ©s sur le banc expĂ©rimental rĂ©alisĂ© au sein du laboratoire, et qui nous ont permis de dĂ©terminer la solution de refroidissement la mieux adaptĂ©e. Cette Ă©tude nous a aussi montrĂ© quâil est plus que nĂ©cessaire dâintĂ©grer des interfaces thermiques « IT» telles que des pĂątes thermiques afin dâassurer un meilleur transfert de chaleur entre les composants Ă©lectroniques et le refroidisseur. La deuxiĂšme partie, reprĂ©sente une Ă©tude approfondie sur les interfaces thermiques qui sont un point dĂ©licat de transfert de chaleur, car elles peuvent avoir plusieurs dizaines de pour cent de la rĂ©sistance thermique globale. Pour garantir une utilisation adĂ©quate et durable de ces matĂ©riaux, plusieurs paramĂštres ont Ă©tĂ© vĂ©rifiĂ©s, en particulier la duretĂ©, la consistance (pas de production de graisse ou dâhuile) et la conductivitĂ© thermique, grĂące Ă un banc de mesures adaptĂ© dâaprĂšs la mĂ©thode normalisĂ© ASTM D5470, grĂące auquel on a pu mesurer le flux de chaleur qui traverse lâĂ©chantillon dâinterface thermique testĂ© et qui est gĂ©nĂ©rĂ© par une source chaude et un source froide qui sont montĂ©es aux extrĂ©mitĂ©s de notre banc.GrĂące Ă lâinstallation CHARME (CERN) et Ă la plate-forme PAVIRMA (Campus des CĂ©zeaux), une sĂ©rie de mesure dâirradiations aux neutrons et aux rayons X sont Ă©galement effectuĂ©es, correspondant Ă lâenvironnement dans lequel elles seront exposĂ©es dans lâexpĂ©rience, dâun cĂŽtĂ© pour identifier les dĂ©gradations et changements possibles sur les rĂ©sistances thermiques par lâanalyse de lâimpĂ©dance thermique, de lâautre pour identifier lâinterface thermique qui convient le mieux Ă notre application et qui permet dâassurer un excellent Ă©change thermique et donc un bon refroidissement de lâĂ©lectronique frontale au sein du trajectographe du dĂ©tecteur LHCb.In the context of the evolution of the biggest circular accelerator of particles «LHC», an important program of upgrade on all the detectors which establishes itself was thrown. Among them, we find the upgrade of the detector LHCb which includes the complete replacement of several sub-detectors. The frequency of high reading of 40MHz, an unprecedented in an experiment of physical appearance of particles, and the environment of severe radiation bound to the increase of the intensity of the LHC, are the main challenges by the new sub-detectors. The work presented in this manuscript, described as a small part of the evolution of the LHCb detector. The development and the construction of a new wide-scale tracker, based on a new technology with scintillating fiber «SciFi», read with photomultipliers to the silicon «SiPM», is one of the key projects of the LHCb upgrade program. The first part, consists in studying the thermal exchanges and designing a cooling system for every Read-Out Box «ROB» which contains two electronic front-end « FE », and which allow to read the data of the detector. The latter has a thermal dissipation about 110W. To ensure the smooth running of electronic components, it is compulsory to set up a cooler. Important constraints are taken into account in this study, the first one represents the space limited compared to the need for the cooling system, the electronic interfaces and mechanical, the second concerns the SiPM. Connected with the electronics by flexible cables, they are located near the electronics «FE» and their temperature of operation is perfectly settled around -40 ° C. Works of digital simulations on the software FloTHERM and ANSYS were led on the experimental bench realized within the laboratory, and which allowed us to determine the best adapted solution of cooling. This study also showed to us that he is more than necessity to integrate thermal interfaces «IT» such as thermal pastas to assure a better transfer of heat between electronic components and cooler. The second part, represents an in-depth study on the thermal interfaces which are a delicate point of transfer of heat, because they can have dozens percent of the global thermal resistance. To guarantee an adequate and sustainable use of these materials, several parameters were verified, in particular hardness, consistency (no production of fat or oil) and the thermal conductivity, thanks to a bench of measures adapted according to the method normalized ASTM D5470, with this bench we could measure the flow of heat through the tested thermal interface sample and which is generated by a hot source and a cold source that are mounted at the ends of our bench.With the installation CHARME (CERN) and PAVIRMA (CĂ©zeaux), a series of measure of irradiations at the neutrons and the X-rays are also made, correspond-ing to the environment in which they will be exposed in the experience, on one side to identify the damages and the possible changes on the thermal resistances by the analysis of the thermal impedance, the other one to identify the thermal interface which suits best our application and which allows to assure an excellent thermal exchange and thus a good cooling of the frontal electronics within the trajectographe of the detector LHCb
The LHCb upgrade I
International audienceThe LHCb upgrade represents a major change of the experiment. The detectors have been almost completely renewed to allow running at an instantaneous luminosity five times larger than that of the previous running periods. Readout of all detectors into an all-software trigger is central to the new design, facilitating the reconstruction of events at the maximum LHC interaction rate, and their selection in real time. The experiment's tracking system has been completely upgraded with a new pixel vertex detector, a silicon tracker upstream of the dipole magnet and three scintillating fibre tracking stations downstream of the magnet. The whole photon detection system of the RICH detectors has been renewed and the readout electronics of the calorimeter and muon systems have been fully overhauled. The first stage of the all-software trigger is implemented on a GPU farm. The output of the trigger provides a combination of totally reconstructed physics objects, such as tracks and vertices, ready for final analysis, and of entire events which need further offline reprocessing. This scheme required a complete revision of the computing model and rewriting of the experiment's software
The LHCb upgrade I
International audienceThe LHCb upgrade represents a major change of the experiment. The detectors have been almost completely renewed to allow running at an instantaneous luminosity five times larger than that of the previous running periods. Readout of all detectors into an all-software trigger is central to the new design, facilitating the reconstruction of events at the maximum LHC interaction rate, and their selection in real time. The experiment's tracking system has been completely upgraded with a new pixel vertex detector, a silicon tracker upstream of the dipole magnet and three scintillating fibre tracking stations downstream of the magnet. The whole photon detection system of the RICH detectors has been renewed and the readout electronics of the calorimeter and muon systems have been fully overhauled. The first stage of the all-software trigger is implemented on a GPU farm. The output of the trigger provides a combination of totally reconstructed physics objects, such as tracks and vertices, ready for final analysis, and of entire events which need further offline reprocessing. This scheme required a complete revision of the computing model and rewriting of the experiment's software
The LHCb upgrade I
International audienceThe LHCb upgrade represents a major change of the experiment. The detectors have been almost completely renewed to allow running at an instantaneous luminosity five times larger than that of the previous running periods. Readout of all detectors into an all-software trigger is central to the new design, facilitating the reconstruction of events at the maximum LHC interaction rate, and their selection in real time. The experiment's tracking system has been completely upgraded with a new pixel vertex detector, a silicon tracker upstream of the dipole magnet and three scintillating fibre tracking stations downstream of the magnet. The whole photon detection system of the RICH detectors has been renewed and the readout electronics of the calorimeter and muon systems have been fully overhauled. The first stage of the all-software trigger is implemented on a GPU farm. The output of the trigger provides a combination of totally reconstructed physics objects, such as tracks and vertices, ready for final analysis, and of entire events which need further offline reprocessing. This scheme required a complete revision of the computing model and rewriting of the experiment's software
The LHCb upgrade I
The LHCb upgrade represents a major change of the experiment. The detectors have been almost completely renewed to allow running at an instantaneous luminosity five times larger than that of the previous running periods. Readout of all detectors into an all-software trigger is central to the new design, facilitating the reconstruction of events at the maximum LHC interaction rate, and their selection in real time. The experiment's tracking system has been completely upgraded with a new pixel vertex detector, a silicon tracker upstream of the dipole magnet and three scintillating fibre tracking stations downstream of the magnet. The whole photon detection system of the RICH detectors has been renewed and the readout electronics of the calorimeter and muon systems have been fully overhauled. The first stage of the all-software trigger is implemented on a GPU farm. The output of the trigger provides a combination of totally reconstructed physics objects, such as tracks and vertices, ready for final analysis, and of entire events which need further offline reprocessing. This scheme required a complete revision of the computing model and rewriting of the experiment's software
The LHCb upgrade I
International audienceThe LHCb upgrade represents a major change of the experiment. The detectors have been almost completely renewed to allow running at an instantaneous luminosity five times larger than that of the previous running periods. Readout of all detectors into an all-software trigger is central to the new design, facilitating the reconstruction of events at the maximum LHC interaction rate, and their selection in real time. The experiment's tracking system has been completely upgraded with a new pixel vertex detector, a silicon tracker upstream of the dipole magnet and three scintillating fibre tracking stations downstream of the magnet. The whole photon detection system of the RICH detectors has been renewed and the readout electronics of the calorimeter and muon systems have been fully overhauled. The first stage of the all-software trigger is implemented on a GPU farm. The output of the trigger provides a combination of totally reconstructed physics objects, such as tracks and vertices, ready for final analysis, and of entire events which need further offline reprocessing. This scheme required a complete revision of the computing model and rewriting of the experiment's software
The LHCb upgrade I
International audienceThe LHCb upgrade represents a major change of the experiment. The detectors have been almost completely renewed to allow running at an instantaneous luminosity five times larger than that of the previous running periods. Readout of all detectors into an all-software trigger is central to the new design, facilitating the reconstruction of events at the maximum LHC interaction rate, and their selection in real time. The experiment's tracking system has been completely upgraded with a new pixel vertex detector, a silicon tracker upstream of the dipole magnet and three scintillating fibre tracking stations downstream of the magnet. The whole photon detection system of the RICH detectors has been renewed and the readout electronics of the calorimeter and muon systems have been fully overhauled. The first stage of the all-software trigger is implemented on a GPU farm. The output of the trigger provides a combination of totally reconstructed physics objects, such as tracks and vertices, ready for final analysis, and of entire events which need further offline reprocessing. This scheme required a complete revision of the computing model and rewriting of the experiment's software