引言在中国科学院和中国政府及世界银行的支持下,建立中国生态系统研究网络(Chinese Ecosystem Research Network,(CERN))的工作是从1988年开始的,至今已经10多年了。中国科学院自50年代初建院以来,至今已经建立了分布在全国的一些重要...引言在中国科学院和中国政府及世界银行的支持下,建立中国生态系统研究网络(Chinese Ecosystem Research Network,(CERN))的工作是从1988年开始的,至今已经10多年了。中国科学院自50年代初建院以来,至今已经建立了分布在全国的一些重要生态类型区域,代表着不同生态系统类型的100多个野外试验站。建立这些野外试验站的最初目的主要是为了帮助当地发展农业、林业、畜牧业和渔业,以及观测和研究像冰川、冻土、泥石流、滑坡等自然现象。在过去的50年中,这些站在帮助当地发展农业、合理利用自然资源、解决环境问题以及推动生态学研究方面都发挥了重要作用。 80年代以来,由于地球系统科学的发展,特别是由于以国际地圈一生物圈计划(IGBP)为代表的全球变化研究项目的启动。展开更多
This study addresses a challenge of parametrizing a resolution function of a neutron beam from the neutron time of flight facility n_TOF at CERN.A difficulty stems from a fact that a resolution function exhibits rathe...This study addresses a challenge of parametrizing a resolution function of a neutron beam from the neutron time of flight facility n_TOF at CERN.A difficulty stems from a fact that a resolution function exhibits rather strong variations in shape,over approximately ten orders of magnitude in neutron energy.To avoid a need for a manual identification of the appropri-ate analytical forms-hindering past attempts at its parametrization-we take advantage of the versatile machine learning techniques.Specifically,we parametrized it by training a multilayer feedforward neural network,relying on a key idea that such network acts as a universal approximator.The proof-of-concept is presented for a resolution function for the first experimental area of the n_TOF facility from the third phase of its operation.We propose an optimal network structure for a resolution function in question,which is also expected to be optimal or near-optimal for other experimental areas and for different phases of n_TOF operation.To reconstruct several resolution function forms in common use from a single para-metrized form,we provide a practical tool in the form of a specialized C++class encapsulating the computationally efficient procedures suited to the task.展开更多
Significant progress was made by the CERN RD39 collaboration in the development of super radiation-hard cryogenic silicon detectors for applications in experiments at LHC, in particular after its future luminosity upg...Significant progress was made by the CERN RD39 collaboration in the development of super radiation-hard cryogenic silicon detectors for applications in experiments at LHC, in particular after its future luminosity upgrade. The detailed modeling shows that the electric field in irradiated silicon detectors can easily be manipulated by the filling state of two deep defect levels at cryogenic temperature. Advanced radiation hard detectors using charge or current injection and the current injected detectors(CID) were developed by RD39. The results show that CID detectors can be operated at the temperature of 100?200 K with much improved charge collection efficiency(CCE) as compared with RT operation. Future studies are developing ultra-hard cryogenic silicon detectors for the LHC upgrade, where the radiation hardness is required up to 1016 neq/cm2, at which trapping will limit the charge collection depth to the range of 20 to 50 μm regardless of the depletion depth. The key of our approach is to use freeze-out trapping to affect CCE.展开更多
The objective of the CERN RD50 Collaboration is to develop radiation hard semiconductor detectors for very high luminosity colliders, in particular, for the upgrade of the large hadron collider (LHC) which itself is s...The objective of the CERN RD50 Collaboration is to develop radiation hard semiconductor detectors for very high luminosity colliders, in particular, for the upgrade of the large hadron collider (LHC) which itself is scheduled to be operational in 2007. The approach of the RD50 has two major research lines, material engineering and device engineering. These are further subdivided into projects covering defect characterization and engineering, new detector materials, detector characterization, new detector structures and full detector systems. Presently, 264 members from 53 institutes are actively participating in the RD50 Collaboration. Detectors made of defect engineered substrates, e.g. high resistivity magnetic Czochralski (MCz-Si), epitaxial silicon (Epi-Si) on Czochralski silicon (Cz-Si) substrate, intentionally thermal donor (TD) compensated p-type MCz-Si and oxygen enriched (DOFZ) silicon, have been demonstrated by the RD50 Collaboration. An overview and highlights of the results of these defect engineering techniques were given in this report.展开更多
Identifying composite crosscutting concerns（CCs） is a research task and challenge of aspect mining.In this paper,we propose a scatter-based graph clustering approach to identify composite CCs.Inspired by the state-o...Identifying composite crosscutting concerns（CCs） is a research task and challenge of aspect mining.In this paper,we propose a scatter-based graph clustering approach to identify composite CCs.Inspired by the state-of-the-art link analysis tech-niques,we propose a two-state model to approximate how CCs tangle with core modules.According to this model,we obtain scatter and centralization scores for each program element.Espe-cially,the scatter scores are adopted to select CC seeds.Further-more,to identify composite CCs,we adopt a novel similarity measurement and develop an undirected graph clustering to group these seeds.Finally,we compare it with the previous work and illustrate its effectiveness in identifying composite CCs.展开更多
The latest steps in the steady evolution of the CERN Computer Centre have been to reduce the multitude of clusters and architectures and to concentrate on commodity hardware.An active RISC decommissioning program has ...The latest steps in the steady evolution of the CERN Computer Centre have been to reduce the multitude of clusters and architectures and to concentrate on commodity hardware.An active RISC decommissioning program has been undertaken to encourage migration to Linux,and a program of merging dedicated experiment clusters into larger shared facilities has been launched.This paper describes these programs and the experiences running the resultant multi-hundred node shared Linux clusters.展开更多
A RadioFrequency Quadrupole(RFQ)cooler-buncher system was developed and implemented in a collinear laser spectroscopy setup.This system converts a continuous ion beam into short bunches while enhancing the beam qualit...A RadioFrequency Quadrupole(RFQ)cooler-buncher system was developed and implemented in a collinear laser spectroscopy setup.This system converts a continuous ion beam into short bunches while enhancing the beam quality and reducing the energy spread.The functionality of the RFQ cooler buncher was verified through offline tests with stable rubidium and indium beams delivered from a surface ion source and a laser ablation ion source,respectively.Bunched ion beams with a full width at half maximum of approximately 2μs in the time-of-flight spectrum were successfully achieved with a transmission efficiency exceeding 60%.The implementation of the RFQ cooler-buncher system also significantly improved the overall transmission efficiency of the collinear laser spectroscopy setup.展开更多
In response to the increasing demand for hadron therapy facilities,significant efforts have been directed toward enhancing the performance of high-gradient and high-transmission injectors for light ion beams.For carbo...In response to the increasing demand for hadron therapy facilities,significant efforts have been directed toward enhancing the performance of high-gradient and high-transmission injectors for light ion beams.For carbon ion irradiations,which offer greater radiobiological efficiency in tumor treatment,recent research has focused on developing high-production sources of fully stripped C^(6+)ions and highly compact,high-frequency RFQ cavities.This study explores the design possibilities of a carbon ion acceleration section using 750 MHz Interdigital H-mode Drift Tube Linacs(IH-DTLs)as a high-efficiency solution for accelerating ions in the 5-10 MeV per nucleon energy range.A particle-tracking routine based on the TRAVEL code was developed to design the acceleration line through a tailored KONUS-type configuration.Three design solutions were proposed and compared,exploring different alternatives regarding the use of a MEBT to match the output beam phase space of the RFQ to the optics of the line,as well as varying considerations for magnetic systems to focus the beam.Additionally,the compatibility of the proposed solutions with the existing design of the carbon ion bent-linac for hadron therapy was assessed.展开更多
At ISOLDE (CERN),an on-line test bench is dedicated to charge breeding experiments with a 14GHz Phoenix ion source,for the investigation of the 1+→n+ scenario at next generation ISOL-type facilities.This year,various...At ISOLDE (CERN),an on-line test bench is dedicated to charge breeding experiments with a 14GHz Phoenix ion source,for the investigation of the 1+→n+ scenario at next generation ISOL-type facilities.This year,various technical developments have been undertaken for intensifying the tests of the on- line performances of the booster with a high diversity of stable and radioactive ion beams.This contribution will present an overview of the latest developments,the current challenges,and some perspectives for the future use of the Phoenix booster for physics experiments at ISOLDE.展开更多
The GTS-LHC ion source,designed and build by CEA Grenoble,was installed and commissioned at CERN in 2005.Since than the source has delivered oxygen and lead ion beams(O^(4+) and Pb^(27+) from the source,Pb^(54+) from ...The GTS-LHC ion source,designed and build by CEA Grenoble,was installed and commissioned at CERN in 2005.Since than the source has delivered oxygen and lead ion beams(O^(4+) and Pb^(27+) from the source,Pb^(54+) from the linac)for the commissioning of the Low Energy Ion Ring(LEIR).Results of this operation and attempts to improve the source performance and reliability,and the linac performance will be presented in this paper.展开更多
文摘引言在中国科学院和中国政府及世界银行的支持下,建立中国生态系统研究网络(Chinese Ecosystem Research Network,(CERN))的工作是从1988年开始的,至今已经10多年了。中国科学院自50年代初建院以来,至今已经建立了分布在全国的一些重要生态类型区域,代表着不同生态系统类型的100多个野外试验站。建立这些野外试验站的最初目的主要是为了帮助当地发展农业、林业、畜牧业和渔业,以及观测和研究像冰川、冻土、泥石流、滑坡等自然现象。在过去的50年中,这些站在帮助当地发展农业、合理利用自然资源、解决环境问题以及推动生态学研究方面都发挥了重要作用。 80年代以来,由于地球系统科学的发展,特别是由于以国际地圈一生物圈计划(IGBP)为代表的全球变化研究项目的启动。
基金supported by the Croatian Science Foundation under the project number HRZZ-IP-2022-10-3878funding from the European Union’s Horizon Europe Research and Innovation programme under Grant Agreement No 101057511Funding Open access funding provided by CERN (European Organization for Nuclear Research).
文摘This study addresses a challenge of parametrizing a resolution function of a neutron beam from the neutron time of flight facility n_TOF at CERN.A difficulty stems from a fact that a resolution function exhibits rather strong variations in shape,over approximately ten orders of magnitude in neutron energy.To avoid a need for a manual identification of the appropri-ate analytical forms-hindering past attempts at its parametrization-we take advantage of the versatile machine learning techniques.Specifically,we parametrized it by training a multilayer feedforward neural network,relying on a key idea that such network acts as a universal approximator.The proof-of-concept is presented for a resolution function for the first experimental area of the n_TOF facility from the third phase of its operation.We propose an optimal network structure for a resolution function in question,which is also expected to be optimal or near-optimal for other experimental areas and for different phases of n_TOF operation.To reconstruct several resolution function forms in common use from a single para-metrized form,we provide a practical tool in the form of a specialized C++class encapsulating the computationally efficient procedures suited to the task.
文摘Significant progress was made by the CERN RD39 collaboration in the development of super radiation-hard cryogenic silicon detectors for applications in experiments at LHC, in particular after its future luminosity upgrade. The detailed modeling shows that the electric field in irradiated silicon detectors can easily be manipulated by the filling state of two deep defect levels at cryogenic temperature. Advanced radiation hard detectors using charge or current injection and the current injected detectors(CID) were developed by RD39. The results show that CID detectors can be operated at the temperature of 100?200 K with much improved charge collection efficiency(CCE) as compared with RT operation. Future studies are developing ultra-hard cryogenic silicon detectors for the LHC upgrade, where the radiation hardness is required up to 1016 neq/cm2, at which trapping will limit the charge collection depth to the range of 20 to 50 μm regardless of the depletion depth. The key of our approach is to use freeze-out trapping to affect CCE.
文摘The objective of the CERN RD50 Collaboration is to develop radiation hard semiconductor detectors for very high luminosity colliders, in particular, for the upgrade of the large hadron collider (LHC) which itself is scheduled to be operational in 2007. The approach of the RD50 has two major research lines, material engineering and device engineering. These are further subdivided into projects covering defect characterization and engineering, new detector materials, detector characterization, new detector structures and full detector systems. Presently, 264 members from 53 institutes are actively participating in the RD50 Collaboration. Detectors made of defect engineered substrates, e.g. high resistivity magnetic Czochralski (MCz-Si), epitaxial silicon (Epi-Si) on Czochralski silicon (Cz-Si) substrate, intentionally thermal donor (TD) compensated p-type MCz-Si and oxygen enriched (DOFZ) silicon, have been demonstrated by the RD50 Collaboration. An overview and highlights of the results of these defect engineering techniques were given in this report.
基金Supported by the National Pre-research Project (513150601)
文摘Identifying composite crosscutting concerns（CCs） is a research task and challenge of aspect mining.In this paper,we propose a scatter-based graph clustering approach to identify composite CCs.Inspired by the state-of-the-art link analysis tech-niques,we propose a two-state model to approximate how CCs tangle with core modules.According to this model,we obtain scatter and centralization scores for each program element.Espe-cially,the scatter scores are adopted to select CC seeds.Further-more,to identify composite CCs,we adopt a novel similarity measurement and develop an undirected graph clustering to group these seeds.Finally,we compare it with the previous work and illustrate its effectiveness in identifying composite CCs.
文摘The latest steps in the steady evolution of the CERN Computer Centre have been to reduce the multitude of clusters and architectures and to concentrate on commodity hardware.An active RISC decommissioning program has been undertaken to encourage migration to Linux,and a program of merging dedicated experiment clusters into larger shared facilities has been launched.This paper describes these programs and the experiences running the resultant multi-hundred node shared Linux clusters.
基金supported by the National Natural Science Foundation of China(Nos.12027809,12350007)National Key R&D Program of China(Nos.2022YFA1605100,2023YFA1606403,and 2023YFE0101600)+1 种基金New Cornerstone Science Foundation through the XPLORER PRIZEfunding from the European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation program under grant agreement No.679038.
文摘A RadioFrequency Quadrupole(RFQ)cooler-buncher system was developed and implemented in a collinear laser spectroscopy setup.This system converts a continuous ion beam into short bunches while enhancing the beam quality and reducing the energy spread.The functionality of the RFQ cooler buncher was verified through offline tests with stable rubidium and indium beams delivered from a surface ion source and a laser ablation ion source,respectively.Bunched ion beams with a full width at half maximum of approximately 2μs in the time-of-flight spectrum were successfully achieved with a transmission efficiency exceeding 60%.The implementation of the RFQ cooler-buncher system also significantly improved the overall transmission efficiency of the collinear laser spectroscopy setup.
基金Project co-funded by European Union in the context of the precommercial public procurement of RD services managed by CDTI E.P.Eco-funded by the European Regional Development Fund(ERDF)as part of the project for the development of a Compact Linear Accelerator for Hadrontherapy,Exp.CPP 03/2023 AB(DCCPI/OCPI)。
文摘In response to the increasing demand for hadron therapy facilities,significant efforts have been directed toward enhancing the performance of high-gradient and high-transmission injectors for light ion beams.For carbon ion irradiations,which offer greater radiobiological efficiency in tumor treatment,recent research has focused on developing high-production sources of fully stripped C^(6+)ions and highly compact,high-frequency RFQ cavities.This study explores the design possibilities of a carbon ion acceleration section using 750 MHz Interdigital H-mode Drift Tube Linacs(IH-DTLs)as a high-efficiency solution for accelerating ions in the 5-10 MeV per nucleon energy range.A particle-tracking routine based on the TRAVEL code was developed to design the acceleration line through a tailored KONUS-type configuration.Three design solutions were proposed and compared,exploring different alternatives regarding the use of a MEBT to match the output beam phase space of the RFQ to the optics of the line,as well as varying considerations for magnetic systems to focus the beam.Additionally,the compatibility of the proposed solutions with the existing design of the carbon ion bent-linac for hadron therapy was assessed.
基金Supported by EU Within the EURONS and EURISOL DS under Respective Contract Numbers RII3-CT-2004-506065 and RIDS 515768
文摘At ISOLDE (CERN),an on-line test bench is dedicated to charge breeding experiments with a 14GHz Phoenix ion source,for the investigation of the 1+→n+ scenario at next generation ISOL-type facilities.This year,various technical developments have been undertaken for intensifying the tests of the on- line performances of the booster with a high diversity of stable and radioactive ion beams.This contribution will present an overview of the latest developments,the current challenges,and some perspectives for the future use of the Phoenix booster for physics experiments at ISOLDE.
文摘The GTS-LHC ion source,designed and build by CEA Grenoble,was installed and commissioned at CERN in 2005.Since than the source has delivered oxygen and lead ion beams(O^(4+) and Pb^(27+) from the source,Pb^(54+) from the linac)for the commissioning of the Low Energy Ion Ring(LEIR).Results of this operation and attempts to improve the source performance and reliability,and the linac performance will be presented in this paper.
