Following its pioneering application in the present LHCb Velo detector, CO2 evaporative cooling has become the consolidated technology for the thermal management of low-temperature operated silicon ...detectors at LHC. ATLAS Insertable B-Layer and CMS Phase I Pixel are successfully operating with such cooling system since a few years and LHCb has selected the same technology for the new Upstream Tracker and the upgraded Velo, both to be installed during LS2. The design of the ATLAS and CMS upgrade silicon detectors is well advanced, and both experiments heavily rely on CO2 evaporative cooling. In order to cope with the new detector requirements, several studies are on-going, in particular on the scaling of the cooling plants, their integration in the existing space and infrastructure, the low temperature operation. A demonstrator cooling system, the “Demo”, is presently in the design phase at CERN. This paper discusses the challenges of the CO2 systems for the phase 2 upgrade of the LHC experiments, the design of the “Demo” cooling system and the integration and operational issues under study, presenting a time-line for the CO2 system development from now up to operation.
In the last few years, CO2 evaporative cooling has been one of the favourite technologies chosen for the thermal management of tracking detectors at LHC. ATLAS Insertable B-Layer and CMS Pixel phase ...1 upgrade have adopted it and their systems are now operational or under commissioning. The CERN PH-DT team is now merging the lessons learnt on these two systems in order to prepare the design and construction of the cooling systems for the new Upstream Tracker and the Velo upgrade in LHCb, due by 2018. Meanwhile, the preliminary design of the ATLAS and CMS full tracker upgrades is started, and both concepts heavily rely on CO2 evaporative cooling. This paper highlights the performances of the systems now in operation and the challenges to overcome in order to scale them up to the requirements of the future generations of trackers. In particular, it focuses on the conceptual design of a new cooling system suited for the large phase 2 upgrade programmes, which will be validated with the construction of a common prototype in the next years.
ATLAS “Baby-DEMO” Zwalinski, L.; Bojdol, K.; Bortolin, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Letnik:
936
Journal Article
Recenzirano
Odprti dostop
Evaporative CO2 has been selected as the main detector cooling technology for the Phase II upgrade of the LHC silicon detectors at CERN. In order to provide input to the ATLAS Pixel TDR about the ...minimum attainable cooling temperature by the end of 2017, ATLAS, with a contribution of CMS, has launched a dedicated detector cooling R&D study nick-named Baby-DEMO. The Baby-DEMO is the demonstration of a typical 2PACL CO2 cooling plant operating at the lowest temperature ever achieved. A real size ATLAS mock-up is used to hold realistic manifolding as its critical path might have strong impact on the cooling performance. Additionally, the “Baby-DEMO” program addresses the study of high power flexible vacuum insulated coaxial transfer lines and warm nose boiling enhancement as possible solutions for the Phase II upgrade. This paper describes the system design including CO2 plant, primary chiller and typical distribution. Challenges and solutions used to achieve the lowest possible evaporation temperatures are reported. The result of this study, even if at the preliminary stage, are of great interest for the design of the cooling systems that ATLAS and CMS will use in the Phase II era.
•Target minimum cooling evaporator temperature achieved, 5kW @ <−40°C at dummy load•Larger than expected temperature gradients observed in flex lines.•Stable long term operation at −47°C accumulator cooling.•Record low temperature of −50°C achieved with manual tricks.
Background
Machine learning (ML) allows the exploration and progressive improvement of very complex high-dimensional data patterns that can be utilised to optimise specific classification and ...prediction tasks, outperforming traditional statistical approaches. An enormous acceleration of ready-to-use tools and artificial intelligence (AI) applications, shaped by the emergence, refinement, and application of powerful ML algorithms in several areas of knowledge, is ongoing. Although such progress has begun to permeate the medical sciences and clinical medicine, implementation in cardiovascular medicine and research is still in its infancy.
Objectives
To lay out the theoretical framework, purpose, and structure of a novel AI consortium.
Methods
We have established a new Dutch research consortium, the CVON-AI, supported by the Netherlands Heart Foundation, to catalyse and facilitate the development and utilisation of AI solutions for existing and emerging cardiovascular research initiatives and to raise AI awareness in the cardiovascular research community. CVON-AI will connect to previously established CVON consortia and apply a cloud-based AI platform to supplement their planned traditional data-analysis approach.
Results
A pilot experiment on the CVON-AI cloud was conducted using cardiac magnetic resonance data. It demonstrated the feasibility of the platform and documented excellent correlation between AI-generated ventricular function estimates as compared to expert manual annotations. The resulting AI solution was then integrated in a web application.
Conclusion
CVON-AI is a new consortium meant to facilitate the implementation and raise awareness of AI in cardiovascular research in the Netherlands. CVON-AI will create an accessible cloud-based platform for cardiovascular researchers, demonstrate the clinical applicability of AI, optimise the analytical methodology of other ongoing CVON consortia, and promote AI awareness through education and training.
Local thermal management of detector electronics through ultra-thin micro-structured silicon cooling plates is a very promising technique for pixel detectors in high energy physics experiments, ...especially at the LHC where the heavily irradiated sensors must be operated at temperatures below −20°C. It combines a very high thermal efficiency with a very low addition of mass and space, and suppresses all problems of CTE mismatch between the heat source and the heat sink. In addition, the use of CO2 as evaporative coolant liquid brings all the benefits of reliable and stable operation, but the high pressures involved impose additional challenges on the micro channel design and the fluidic connectivity. A series of designs have already been prototyped and tested for LHCb. The challenges, the current status of the measurements and the solutions under development will be described.
In the frame of the progress towards the High Luminosity Program of the Large Hadron Collider at CERN, the ATLAS and CMS experiments are boosting the preparation of their new environmental friendly ...low temperature detector cooling systems. This paper will present a general overview of the progress in development and construction of the future CO2 cooling systems for silicon detectors at ATLAS and CMS (trackers, calorimeters and timing layers), due for implementation during the 3rd Long Shut Down of LHC (LS3). We will describe the selected technology for the primary chillers, based on an innovative transcritical cycle of R744 (refrigerant grade CO2) as coolant, and the oil-free secondary “on detector” CO2 pumped loop, based on the evolution of the successful 2 Phase Accumulator Control Loop (2PACL) concept. Different detector layers will profit from an homogenized infrastructure and will share multi-level redundancy that we will describe in details. The technical progresses achieved by the EP-DT group at CERN over the last years will be discussed in view of the challenges and key solutions developed to cope with the unprecedented scale of the systems. We will finally present how mechanics- and controls-related problems have been addressed via a vigorous prototyping programme, aiming at cost- and resource-effective construction of the final systems, which is starting now.
This study describes the successful upgrade of a mechanically pumped CO2 two-phase cooling system in space by designing a new pump module for the Alpha Magnetic Spectrometer-02 on the International ...Space Station. Key factors for mission success are emphasized, including achieving high coolant filling accuracy within 10% of the target and maintaining system stability within ±1 °C. The impact of adding radiators to improve cooling efficiency is examined, and it is found that operating multi-radiators out-of-phase does not significantly affect system reliability. The centrifugal pump design is shown to allow for better lubricant circulation, while the in-house designed controller incorporates protective measures to prevent cavitation, overheating, and over-current. This research advances the understanding of circulation loop systems and their upgrades in space and demonstrates the potential for extending the lifetime of space-borne mechanically pumped two-phase cooling systems.
•First in-space upgrade of a pumped two-phase cooling system.•Quantitative on-orbit fluid transfer achieves 7% accuracy.•Superior system control stability of 1 °C with multiple out-f-phase radiators.•Prolonged mechanical pump lifetime via hardware and software manners.
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