The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 3...The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.展开更多
The discovery of the Higgs boson with its mass around 125 GeV by the ATLAS and CMS Collaborations marked the beginning of a new era in high energy physics.The Higgs boson will be the subject of extensive studies of th...The discovery of the Higgs boson with its mass around 125 GeV by the ATLAS and CMS Collaborations marked the beginning of a new era in high energy physics.The Higgs boson will be the subject of extensive studies of the ongoing LHC program.At the same time,lepton collider based Higgs factories have been proposed as a possible next step beyond the LHC,with its main goal to precisely measure the properties of the Higgs boson and probe potential new physics associated with the Higgs boson.The Circular Electron Positron Collider(CEPC)is one of such proposed Higgs factories.The CEPC is an e^+e^- circular collider proposed by and to be hosted in China.Located in a tunnel of approximately 100 km in circumference,it will operate at a center-of-mass energy of 240 GeV as the Higgs factory.In this paper,we present the first estimates on the precision of the Higgs boson property measurements achievable at the CEPC and discuss implications of these measurements.展开更多
Purpose Xi'an Institute of Optics and Precision Mechanics of CAS is developing a novel MCP-PMT with 2×2 matrix anode pixels with a time resolution of picosecond level.It is composed of a cermet shell,bi-alkal...Purpose Xi'an Institute of Optics and Precision Mechanics of CAS is developing a novel MCP-PMT with 2×2 matrix anode pixels with a time resolution of picosecond level.It is composed of a cermet shell,bi-alkali photocathode,and V-type cascade MCP layers.In order to study the method of measuring the characteristics of such MCP-PMT with picosecond time resolution,we develop a PMT test system to test its performance.Methods A voltage divider resistor circuit for the MCP-PMT is designed to meet the requirements of both high gain and fast time response.The test system includes a picosecond laser source in the single-photon mode,a high-bandwidth oscilloscope,and another fast MCP-PMT as reference.Full waveforms of PMT signals are collected and analyzed offline.The overall system time error is 26 ps.Results The test result shows that the gain of the MCP-PMT achieves 1 x 107.The transit time spread(TTS)of all channels is better than 60 ps(σ).The uniformity and crosstalk among adjacent channels are also studied by scanning each channel's response along the photocathode plane.Conclusions The MCP-PMT shows excellent timing performance and the potential of achieving better spatial resolution by further pixelation.展开更多
基金support from diverse funding sources,including the National Key Program for S&T Research and Development of the Ministry of Science and Technology(MOST),Yifang Wang's Science Studio of the Ten Thousand Talents Project,the CAS Key Foreign Cooperation Grant,the National Natural Science Foundation of China(NSFC)Beijing Municipal Science&Technology Commission,the CAS Focused Science Grant,the IHEP Innovation Grant,the CAS Lead Special Training Programthe CAS Center for Excellence in Particle Physics,the CAS International Partnership Program,and the CAS/SAFEA International Partnership Program for Creative Research Teams.
文摘The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.
基金Supported by the National Key Program for S&T Researh and Development(2016YFA0400400)CAS Center for Excellence in Particle Physics+12 种基金Yifang Wang’s Science Studio of the Ten Thousand Talents Projectthe CAS/SAFEA International Partnership Program for Creative Research Teams(H751S018S5)IHEP Innovation Grant(Y4545170Y2)Key Research Program of Frontier Sciences,CAS(XQYZDY-SSW-SLH002)Chinese Academy of Science Special Grant for Large Scientific Project(113111KYSB20170005)the National Natural Science Foundation of China(11675202)the Hundred Talent Programs of Chinese Academy of Science(Y3515540U1)the National 1000 Talents Program of ChinaFermi Research Alliance,LLC(DE-AC02-07CH11359)the NSF(PHY1620074)by the Maryland Center for Fundamental Physics(MCFP)Tsinghua University Initiative Scientific Research Programthe Beijing Municipal Science and Technology Commission project(Z181100004218003)
文摘The discovery of the Higgs boson with its mass around 125 GeV by the ATLAS and CMS Collaborations marked the beginning of a new era in high energy physics.The Higgs boson will be the subject of extensive studies of the ongoing LHC program.At the same time,lepton collider based Higgs factories have been proposed as a possible next step beyond the LHC,with its main goal to precisely measure the properties of the Higgs boson and probe potential new physics associated with the Higgs boson.The Circular Electron Positron Collider(CEPC)is one of such proposed Higgs factories.The CEPC is an e^+e^- circular collider proposed by and to be hosted in China.Located in a tunnel of approximately 100 km in circumference,it will operate at a center-of-mass energy of 240 GeV as the Higgs factory.In this paper,we present the first estimates on the precision of the Higgs boson property measurements achievable at the CEPC and discuss implications of these measurements.
基金supported by the National Natural Sci-ence Foundation of China,Nos.11775217 and 11675172
文摘Purpose Xi'an Institute of Optics and Precision Mechanics of CAS is developing a novel MCP-PMT with 2×2 matrix anode pixels with a time resolution of picosecond level.It is composed of a cermet shell,bi-alkali photocathode,and V-type cascade MCP layers.In order to study the method of measuring the characteristics of such MCP-PMT with picosecond time resolution,we develop a PMT test system to test its performance.Methods A voltage divider resistor circuit for the MCP-PMT is designed to meet the requirements of both high gain and fast time response.The test system includes a picosecond laser source in the single-photon mode,a high-bandwidth oscilloscope,and another fast MCP-PMT as reference.Full waveforms of PMT signals are collected and analyzed offline.The overall system time error is 26 ps.Results The test result shows that the gain of the MCP-PMT achieves 1 x 107.The transit time spread(TTS)of all channels is better than 60 ps(σ).The uniformity and crosstalk among adjacent channels are also studied by scanning each channel's response along the photocathode plane.Conclusions The MCP-PMT shows excellent timing performance and the potential of achieving better spatial resolution by further pixelation.