Parkinson’s disease(PD)is one of the primary vital degenerative diseases that affect the Central Nervous System among elderly patients.It affect their quality of life drastically and millions of seniors are diagnosed...Parkinson’s disease(PD)is one of the primary vital degenerative diseases that affect the Central Nervous System among elderly patients.It affect their quality of life drastically and millions of seniors are diagnosed with PD every year worldwide.Several models have been presented earlier to detect the PD using various types of measurement data like speech,gait patterns,etc.Early identification of PD is important owing to the fact that the patient can offer important details which helps in slowing down the progress of PD.The recently-emerging Deep Learning(DL)models can leverage the past data to detect and classify PD.With this motivation,the current study develops a novel Colliding Bodies Optimization Algorithm with Optimal Kernel Extreme Learning Machine(CBO-OKELM)for diagnosis and classification of PD.The goal of the proposed CBO-OKELM technique is to identify whether PD exists or not.CBO-OKELM technique involves the design of Colliding Bodies Optimization-based Feature Selection(CBO-FS)technique for optimal subset of features.In addition,Water Strider Algorithm(WSA)with Kernel Extreme Learning Machine(KELM)model is also developed for the classification of PD.CBO algorithm is used to elect the optimal set of fea-tures whereas WSA is utilized for parameter tuning of KELM model which alto-gether helps in accomplishing the maximum PD diagnostic performance.The experimental analysis was conducted for CBO-OKELM technique against four benchmark datasets and the model portrayed better performance such as 95.68%,96.34%,92.49%,and 92.36%on Speech PD,Voice PD,Hand PD Mean-der,and Hand PD Spiral datasets respectively.展开更多
A monolithically active-passive integrated colliding pulse mode-locked semiconductor laser is demonstrated in the InGaAsP//InP material system. The device is mode locked at the second harmonic passive mode-locking reg...A monolithically active-passive integrated colliding pulse mode-locked semiconductor laser is demonstrated in the InGaAsP//InP material system. The device is mode locked at the second harmonic passive mode-locking regime with a wide mode-locking range. Pulse trains with the repetition rate of 40 GHz, 3-dB rf line width of 25 kHz, the pulse width of 2.5 ps, and a nearly transform-limited time-bandwidth product of 0.53 are obtained.展开更多
This article looks for the necessary conditions to use Deuterium-Deuterium (D-D) fusion for a large power plant. At the moment, for nearly all the projects (JET, ITER…) only the Deuterium-Tritium (D-T) fuel is consid...This article looks for the necessary conditions to use Deuterium-Deuterium (D-D) fusion for a large power plant. At the moment, for nearly all the projects (JET, ITER…) only the Deuterium-Tritium (D-T) fuel is considered for a power plant. However, as shown in this article, even if a D-D reactor would be necessarily much bigger than a D-T reactor due to the much weaker fusion reactivity of the D-D fusion compared to the D-T fusion, a D-D reactor size would remain under an acceptable size. Indeed, a D-D power plant would be necessarily large and powerful, i.e. the net electric power would be equal to a minimum of 1.2 GWe and preferably above 10 GWe. A D-D reactor would be less complex than a D-T reactor as it is not necessary to obtain Tritium from the reactor itself. It is proposed the same type of reactor yet proposed by the author in a previous article, i.e. a Stellarator “racetrack” magnetic loop. The working of this reactor is continuous. It is reminded that the Deuterium is relatively abundant on the sea water, and so it constitutes an almost inexhaustible source of energy. Thanks to secondary fusions (D-T and D-He3) which both occur at an appreciable level above 100 keV, plasma can stabilize around such high equilibrium energy (i.e. between 100 and 150 keV). The mechanical gain (Q) of such reactor increases with the internal pipe radius, up to 4.5 m. A radius of 4.5 m permits a mechanical gain (Q) of about 17 which thanks to a modern thermo-dynamical conversion would lead to convert about 21% of the thermal power issued from the D-D reactor in a net electric power of 20 GWe. The goal of the article is to create a physical model of the D-D reactor so as to estimate this one without the need of a simulator and finally to estimate the dimensions, power and yield of such D-D reactor for different net electrical powers. The difficulties of the modeling of such reactor are listed in this article and would certainly be applicable to a future D-He3 reactor, if any.展开更多
Summary of main observation and conclusion Atomistic dynamics of protonated polyglycine, glyn-H^+(n = 3, 5, and 7), colliding with a fluorinated octanethiol self-assembled monolayer (F-SAM) surface has been studied by...Summary of main observation and conclusion Atomistic dynamics of protonated polyglycine, glyn-H^+(n = 3, 5, and 7), colliding with a fluorinated octanethiol self-assembled monolayer (F-SAM) surface has been studied by trajectory calculations. The effects of peptide size on the collision processes and energy transfer efficiencies are emphasized and discussed in detail. The simulations show that the fraction of trapping, which is related to the soft-landing process, dramatically drops with the in crease in collisi on energy, but gently increases with the peptide size. The average energy transfer to the peptide ion's internal degrees of freedom, AEint, is compared with previous experiments. The limiting probability Po of energy transfer to the surface is given by fitting a function of Poexp(—b/&). Our results suggest that the efficiencies of energy transfer are less dependent on the masses, even the categories of the peptide ions, and are determined by the character of the surfaces.展开更多
Heavy Ion Fusion makes use of the Relativistic Heavy Ion Collider at Brookhaven National Lab and the Large Hadron Collider in Geneva, Switzerland for Inertial Confinement Fusion. Two Storage Rings, which may or may no...Heavy Ion Fusion makes use of the Relativistic Heavy Ion Collider at Brookhaven National Lab and the Large Hadron Collider in Geneva, Switzerland for Inertial Confinement Fusion. Two Storage Rings, which may or may not initially be needed, added to each of the Colliders increases the intensity of the Heavy Ion Beams making it comparable to the Total Energy delivered to the DT target by the National Ignition Facility at the Lawrence Livermore Lab. The basic Physics involved gives Heavy Ion Fusion an advantage over Laser Fusion because heavy ions have greater penetration power than photons. The Relativistic Heavy Ion Collider can be used as a Prototype Heavy Ion Fusion Reactor for the Large Hadron Collider.展开更多
A new generation of high power laser facilities will provide laser pulses with extremely high powers of 10 petawatt(PW)and even 100 PW, capable of reaching intensities of 1023 W/cm^2 in the laser focus. These ultra-hi...A new generation of high power laser facilities will provide laser pulses with extremely high powers of 10 petawatt(PW)and even 100 PW, capable of reaching intensities of 1023 W/cm^2 in the laser focus. These ultra-high intensities are nevertheless lower than the Schwinger intensity IS= 2.3×1029 W/cm^2 at which the theory of quantum electrodynamics(QED) predicts that a large part of the energy of the laser photons will be transformed to hard Gamma-ray photons and even to matter, via electron–positron pair production. To enable the investigation of this physics at the intensities achievable with the next generation of high power laser facilities, an approach involving the interaction of two colliding PW laser pulses is being adopted. Theoretical simulations predict strong QED effects with colliding laser pulses of 10 PW focused to intensities 10^(22) W/cm^2.展开更多
An electron injector concept for a laser-plasma accelerator has been developed which relies on the use of counter propagating ultrashort laser pulses. In this paper, we use OOPIC the fully self-consistent, twodimensio...An electron injector concept for a laser-plasma accelerator has been developed which relies on the use of counter propagating ultrashort laser pulses. In this paper, we use OOPIC the fully self-consistent, twodimensional, particle-in-cell code to make a parameter study to determine the bunches that can be obtained through collisions of two collinear laser pulses in uniform plasma. A series of simulations show that one can obtain a short (<10fs) bunch with its charge of about 15pC, and energy spread of about 15%. We also discussed the variation of the transverse spot size of the electron bunch and found the bunch would undergo the betatron oscillations.展开更多
Lambda polarization can be measured through its self-analyzing weak decay, making it an ideal candidate for studying spin effects in high-energy scattering. In lepton-nucleon deep inelastic scattering(DIS), Lambda pol...Lambda polarization can be measured through its self-analyzing weak decay, making it an ideal candidate for studying spin effects in high-energy scattering. In lepton-nucleon deep inelastic scattering(DIS), Lambda polarization measurements can probe polarized parton distribution functions(PDFs) and polarized fragmentation functions(FFs). One of the most promising facilities for high-energy nuclear physics research is the proposed Electron-ion collider in China(EicC). As a next-generation facility, EicC is set to advance our understanding of nuclear physics to new heights. In this article, we study the Lambda production in electron-proton collisions at the EicC energy, in particular the reconstruction of Lambda based on the performance of the designed EicC detector. In addition, taking spontaneous transverse polarization as an example, we provide a theoretical prediction with a statistical projection based on one month of EicC data, offering valuable insights into future research prospects.展开更多
In the standard fusion reactors, mainly tokamaks, the mechanical gain obtained is below 1. On the other hand, there are colliding beam fusion reactors, for which, the not neutral plasma and the space charge limit the ...In the standard fusion reactors, mainly tokamaks, the mechanical gain obtained is below 1. On the other hand, there are colliding beam fusion reactors, for which, the not neutral plasma and the space charge limit the number of fusions to a very small number. Consequently, the mechanical gain is extremely low. The proposed reactor is also a colliding beam fusion reactor, configured in Stellarator, using directed beams. D+/T+ ions are injected in opposition, with electrons, at high speeds, so as to form a neutral beam. All these particles turn in a magnetic loop in form of figure of “0” (“racetrack”). The plasma is initially non-thermal but, as expected, rapidly becomes thermal, so all states between non-thermal and thermal exist in this reactor. The main advantage of this reactor is that this plasma after having been brought up near to the optimum conditions for fusion (around 68 keV), is then maintained in this state, thanks to low energy non-thermal ions (≤15 keV). So the energetic cost is low and the mechanical gain (</span><i><span style="font-family:Verdana;">Q</span></i><span style="font-family:Verdana;">) is high (</span></span><span style="font-family:Verdana;">>></span><span style="font-family:Verdana;">1). The goal of this article is to study a different type of fusion reactor, its advantages (no net plasma current inside this reactor, so no disruptive instabilities and consequently a continuous working, a relatively simple way to control the reactor thanks to the particles injectors), and its drawbacks, using a simulator tool. The finding results are valuable for possible future fusion reactors able to generate massive energy in a cleaner and safer way than fission reactors.展开更多
The Beijing spectrometer Ⅲ (BESⅢ) beam pipe is in the center of the BESⅢ, which is the detector of the upgrade project of Beijing electron and positron collider (BEPC Ⅱ). Electrons and positrons collide in the...The Beijing spectrometer Ⅲ (BESⅢ) beam pipe is in the center of the BESⅢ, which is the detector of the upgrade project of Beijing electron and positron collider (BEPC Ⅱ). Electrons and positrons collide in the BESⅢ beam pipe. According to the demands of the BEPC Ⅱ, a key program of Chinese Academy of Sciences, the BESⅢ beam pipe is designed based on the finite elements analysis. The BESIII beam pipe is installed in the inner cylinder of the BESⅢ drift chamber. As a vacuum tube, the BESIII beam pipe is designed as 1 000 mm in length, 63 mm in inner diameter and 114 mm in outer diameter, respectively. The BESIII beam pipe consists of a central beryllium pipe cooled by EDM-1, the oil No.1 for electric discharge machining, and two extended copper pipes cooled by deionized water (DW). The three parts are jointed by vacuum welding. Factors taken into account in the design are as follows. ① The wall thickness of the central beryllium pipe should be designed as small as possible to reduce the multi-scattering and improve the particle momentum resolution. And the wall thickness of the extended copper pipe should be designed as large as possible to protect the detectors from the backgrounds. ②The BESⅢ beam pipe must be sufficiently cooled to avoid the damage and prevents its influence to the BESⅢ drift chamber (DC) operation. The inner surface temperature of the DC inner cylinder must be maintained at 293±2 K. ③ The magnetic permeability of the materials used in the BESⅢ beam pipe must be less than 1.05 H/m to avoid large magnetic field distortions. ④ The static pressure of the vacuum chamber of the BESⅢ beam pipe must be less than 800 μPa. The simulating results show that the designed structure of the BESⅢ beam pipe satisfies the requirements mentioned above. The structure design scheme is evaluated and adonted hv the headouarters of BEPCⅡ.展开更多
Based on the LINAC of BEPCII, a high-polarized, high bightness, energy-tunable, monoenergetic laser compton backscattering (LCS)gamma-ray source is under construction at IHEP. The gamma-ray energy range is from 1 MeV ...Based on the LINAC of BEPCII, a high-polarized, high bightness, energy-tunable, monoenergetic laser compton backscattering (LCS)gamma-ray source is under construction at IHEP. The gamma-ray energy range is from 1 MeV to 111 MeV. It is a powerful and hopeful researchplatform to reveal the underlying physics of the nuclear, the basic particles and the vacuum or to check the exist basic physical models, quantumelectrodynamic (QED) theories. In the platform, a 1.064 mm Nd:YAG laser system and a 10.6 mm CO_(2) laser system are employed. All the triggersignals to the laser system and the electron control system are from the only reference clock at the very beginning of the LINAC to make sure thetemporal synchronization. Two optical transition radiation (OTR) targets and two charged-couple devices (CCD) are used to monitor and to alignthe electron beam and the laser beam. With the LCS gamma-ray source, it is proposed to experimentally check the gamma-ray calibrations, thephoton-nuclear physics, nuclear astrophysics and some basic QED phenomena.展开更多
The topcolour-assisted technicolour (TC2) model is an interesting dynamical theory among the various new physics models. We cMculate the total tt cross section and the relative correction of the TC2 model to the cro...The topcolour-assisted technicolour (TC2) model is an interesting dynamical theory among the various new physics models. We cMculate the total tt cross section and the relative correction of the TC2 model to the cross section at Tevatron Run Ⅱ and LHC. At the Tevatron Run Ⅱ, the cross section predicted by the standard model (SM) is consistent with the experimental data, and in most parameter spaces of the TC2 model, the relative correction of the TC2 model to the cross section is too small to be detectable. We find that the tt cross section is more sensitive to the parameters of the TC2 model at the LHC and the relative correction of the TC2 model to the cross section is over 10% in general. Such a value of the relative correction should be large enough to be detectable at the LHC. Therefore, it is promising to find the clue of the TC2 model via the tt production at the LHC.展开更多
The beam-beam effects in a hadron collider with an unprecedented energy scale were studied.These effects are strongly related to the attainable luminosity of the collider.Long-range interactions were identified as the...The beam-beam effects in a hadron collider with an unprecedented energy scale were studied.These effects are strongly related to the attainable luminosity of the collider.Long-range interactions were identified as the major factor limiting the dynamic aperture,which is strongly dependent on the crossing angle,β*,and bunch population.Different mitigation methods of the beam-beam effects were addressed,with a focus on the compensation of long-range interactions by electric curren wires.The CEPC-SPPC project is a two-stage large circular collider,with a first-stage circular electron-positron collider(CEPC)and a second-stage super proton-proton collider(SPPC).The design of the SPPC aims to achieve a center-of-mass energy of 75 TeV and peak luminosity of approximately 1×10^(35) cm^(-2)s^(-1).We studied the beam-beam effects in the SPPC and tested the effectiveness of the mitigation methods.We found that with compensation using electric current wires,the dynamic aperture is at an acceptable level.Moreover,considering the significant emittance damping in this future proton-proton collider the beam-beam effects and compensation are more complicated and are studied using long-term tracking.It was found that with a smaller emittance,the head-on interactions with a crossing angle become more prominent in reducing the beam stability,and combined head-on and long-range compensation is needed to improve the beam quality.When the reduction in population owing to burnoff was included,it was found that the coupling between the transverse and longitudinal planes at smaller emittance is the main driving source of the instabilities.Thus,crab cavities and emittance control are also necessary than just the compensation of the long-range interactions to improve the beam stability.This study serves as an example for studying the beam-beam effects in future proton-proton colliders.展开更多
The European organization for nuclear research(CERN)is planning a high performance particle collider by 2050,which will update the currently used Large Hadron Collider(LHC).The design of the new experiment facility in...The European organization for nuclear research(CERN)is planning a high performance particle collider by 2050,which will update the currently used Large Hadron Collider(LHC).The design of the new experiment facility includes the definition of a suitable communication infrastructure to support the future needs of scientists.The huge amount of data collected by the measurement devices call for a data rate of at least 1 Gb/s per node,while the need of timely control of instruments requires a low latency of the order of 0.01μs.Moreover,the main tunnel will be 100 km long,and will need appropriate coverage for voice and data traffic,in a special underground environment subject also to strong radiations.Reliable voice,data and video transmission in a tunnel of this length is necessary to ensure timely and localized intervention,reducing access time.In addition,using wireless communication for voice,control and data acquisition of accelerator technical systems could lead to a significant reduction in cabling costs,installation times and maintenance efforts.The communication infrastructure of the Future Circular Collider(FCC)tunnel must be able to circumvent the problems of radioactivity,omnipresent in the tunnel.Current technologies transceivers cannot transmit in such a severely radioactive environment.This is due to the immediate destruction of any active or passive equipment by radioactivity.The scope of this paper is to determine the feasibility of robust wireless transmission in an underground radioactive tunnel environment.The network infrastructure design to meet the demand will be introduced,and the performance of different wireless technologies will be evaluated.展开更多
To reduce the energy demand and operation cost for circular electron positron collider(CEPC), the high efficiency klystrons are being developed at Institute of High Energy Physics, Chinese Academy of Sciences. A 800-k...To reduce the energy demand and operation cost for circular electron positron collider(CEPC), the high efficiency klystrons are being developed at Institute of High Energy Physics, Chinese Academy of Sciences. A 800-k W continuous wave(CW) klystron operating at frequency of 650-MHz has been designed. The results of beam–wave interaction simulation with several different codes are presented. The efficiency is optimized to be 65% with a second harmonic cavity in three-dimensional(3D) particle-in-cell code CST. The effect of cavity frequency error and mismatch load on efficiency of klystron have been investigated. The design and cold test of reentrant cavities are described, which meet the requirements of RF section design. So far, the manufacturing and high-power test of the first klystron prototype have been completed.When the gun operated at DC voltage of 80 k V and current of 15.4 A, the klystron peak power reached 804 k W with output efficiency of about 65.3% at 40% duty cycle. The 1-d B bandwidth is ±0.8 MHZ. Due to the crack of ceramic window, the CW power achieved about 700 kW. The high-power test results are in good agreement with 3D simulation.展开更多
The gauge extension of the standard model with the U(1)B-L+xy symmetry predicts the existence of a lightgauge boson Z′ with small couplings to ordinary fermions. We discuss its contributions to the muon anomalous ...The gauge extension of the standard model with the U(1)B-L+xy symmetry predicts the existence of a lightgauge boson Z′ with small couplings to ordinary fermions. We discuss its contributions to the muon anomalous magnetic moment αμ. Taking account of the constraints on the relevant free parameters, we further calculate the contributions of the light gauge boson Z′ to the Higgs-strahlung processes e+ e-→ZH and e+ e- →Z′H.展开更多
Dark matter has been in the discussion of important theories for long time. As technology developed, more and more particles have been suggested to be the candidate of dark matter. This review will first discuss the o...Dark matter has been in the discussion of important theories for long time. As technology developed, more and more particles have been suggested to be the candidate of dark matter. This review will first discuss the observation evidence of the existence of dark matter in the aspect of cosmic microwave background, galaxy rotation curves, velocity dispersions and gravitational lensing. We then focus on some important collider researches, such as HL-LHC and CEPC about dark matter candidates: WIMPs. Finally, we extend the topic considering dark energy and inflation.展开更多
It is proposed to place the arcs of an SLC-type facility inside the tunnel of a Future Circular Collider (FCC). Accelerated by a linear accelerator (linac), electron and positron beams would traverse the bending arcs ...It is proposed to place the arcs of an SLC-type facility inside the tunnel of a Future Circular Collider (FCC). Accelerated by a linear accelerator (linac), electron and positron beams would traverse the bending arcs in opposite directions and collide at centre-of-mass energies considerably exceeding those attainable at circular e+e−colliders. The proposed SLC-type facility would have the same luminosity as a conventional two-linace e+e−collider. Using an optical free-electron laser, the facility could be converted into a γγ collider. A superconducting L-band linac at the proposed facility may form a part of the injector chain for a 100-TeV proton collider in the FCC tunnel. The whole accelerator complex would serve as a source of e+e−, γγ, pp and ep interactions. The L-band linac could also be used to produce high-intensity neutrino, kaon and muon beams for fixed-target experiments, as well as X-ray free-electron laser (XFEL) photons for applications in material science and medicine.展开更多
In many models stability of Dark Matter particles D is ensured by conservation of a new quantum number referred to as D -parity. Our models also contain charged D -odd particles D± with the same spin as D. (For m...In many models stability of Dark Matter particles D is ensured by conservation of a new quantum number referred to as D -parity. Our models also contain charged D -odd particles D± with the same spin as D. (For more information,please refer to the PDF.)展开更多
This is the second paper by the author describing versatile accelerator complexes that could be built at a Future Circular Collider (FCC) in order to produce e+e-, γγ and ep collisions. The facility described here f...This is the second paper by the author describing versatile accelerator complexes that could be built at a Future Circular Collider (FCC) in order to produce e+e-, γγ and ep collisions. The facility described here features an ILC-based e+e- collider placed tangentially to the FCC tunnel. If the collider is positioned asymmetrically with respect to the FCC tunnel, electron (or positron) bunches could be accelerated by both linacs before they are brought into collision with the 50-TeV beams from the FCC proton storage ring (FCC-pp). The two linacs may also form a part of the injector chain for FCC-pp. The facility could be converted into a γγ collider or a source of multi-MW beams for fixed-target experiments.展开更多
基金Taif University Researchers Supporting Project number(TURSP-2020/161),Taif University,Taif,Saudi Arabia.
文摘Parkinson’s disease(PD)is one of the primary vital degenerative diseases that affect the Central Nervous System among elderly patients.It affect their quality of life drastically and millions of seniors are diagnosed with PD every year worldwide.Several models have been presented earlier to detect the PD using various types of measurement data like speech,gait patterns,etc.Early identification of PD is important owing to the fact that the patient can offer important details which helps in slowing down the progress of PD.The recently-emerging Deep Learning(DL)models can leverage the past data to detect and classify PD.With this motivation,the current study develops a novel Colliding Bodies Optimization Algorithm with Optimal Kernel Extreme Learning Machine(CBO-OKELM)for diagnosis and classification of PD.The goal of the proposed CBO-OKELM technique is to identify whether PD exists or not.CBO-OKELM technique involves the design of Colliding Bodies Optimization-based Feature Selection(CBO-FS)technique for optimal subset of features.In addition,Water Strider Algorithm(WSA)with Kernel Extreme Learning Machine(KELM)model is also developed for the classification of PD.CBO algorithm is used to elect the optimal set of fea-tures whereas WSA is utilized for parameter tuning of KELM model which alto-gether helps in accomplishing the maximum PD diagnostic performance.The experimental analysis was conducted for CBO-OKELM technique against four benchmark datasets and the model portrayed better performance such as 95.68%,96.34%,92.49%,and 92.36%on Speech PD,Voice PD,Hand PD Mean-der,and Hand PD Spiral datasets respectively.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61335009,61274046 and 61474111
文摘A monolithically active-passive integrated colliding pulse mode-locked semiconductor laser is demonstrated in the InGaAsP//InP material system. The device is mode locked at the second harmonic passive mode-locking regime with a wide mode-locking range. Pulse trains with the repetition rate of 40 GHz, 3-dB rf line width of 25 kHz, the pulse width of 2.5 ps, and a nearly transform-limited time-bandwidth product of 0.53 are obtained.
文摘This article looks for the necessary conditions to use Deuterium-Deuterium (D-D) fusion for a large power plant. At the moment, for nearly all the projects (JET, ITER…) only the Deuterium-Tritium (D-T) fuel is considered for a power plant. However, as shown in this article, even if a D-D reactor would be necessarily much bigger than a D-T reactor due to the much weaker fusion reactivity of the D-D fusion compared to the D-T fusion, a D-D reactor size would remain under an acceptable size. Indeed, a D-D power plant would be necessarily large and powerful, i.e. the net electric power would be equal to a minimum of 1.2 GWe and preferably above 10 GWe. A D-D reactor would be less complex than a D-T reactor as it is not necessary to obtain Tritium from the reactor itself. It is proposed the same type of reactor yet proposed by the author in a previous article, i.e. a Stellarator “racetrack” magnetic loop. The working of this reactor is continuous. It is reminded that the Deuterium is relatively abundant on the sea water, and so it constitutes an almost inexhaustible source of energy. Thanks to secondary fusions (D-T and D-He3) which both occur at an appreciable level above 100 keV, plasma can stabilize around such high equilibrium energy (i.e. between 100 and 150 keV). The mechanical gain (Q) of such reactor increases with the internal pipe radius, up to 4.5 m. A radius of 4.5 m permits a mechanical gain (Q) of about 17 which thanks to a modern thermo-dynamical conversion would lead to convert about 21% of the thermal power issued from the D-D reactor in a net electric power of 20 GWe. The goal of the article is to create a physical model of the D-D reactor so as to estimate this one without the need of a simulator and finally to estimate the dimensions, power and yield of such D-D reactor for different net electrical powers. The difficulties of the modeling of such reactor are listed in this article and would certainly be applicable to a future D-He3 reactor, if any.
文摘Summary of main observation and conclusion Atomistic dynamics of protonated polyglycine, glyn-H^+(n = 3, 5, and 7), colliding with a fluorinated octanethiol self-assembled monolayer (F-SAM) surface has been studied by trajectory calculations. The effects of peptide size on the collision processes and energy transfer efficiencies are emphasized and discussed in detail. The simulations show that the fraction of trapping, which is related to the soft-landing process, dramatically drops with the in crease in collisi on energy, but gently increases with the peptide size. The average energy transfer to the peptide ion's internal degrees of freedom, AEint, is compared with previous experiments. The limiting probability Po of energy transfer to the surface is given by fitting a function of Poexp(—b/&). Our results suggest that the efficiencies of energy transfer are less dependent on the masses, even the categories of the peptide ions, and are determined by the character of the surfaces.
文摘Heavy Ion Fusion makes use of the Relativistic Heavy Ion Collider at Brookhaven National Lab and the Large Hadron Collider in Geneva, Switzerland for Inertial Confinement Fusion. Two Storage Rings, which may or may not initially be needed, added to each of the Colliders increases the intensity of the Heavy Ion Beams making it comparable to the Total Energy delivered to the DT target by the National Ignition Facility at the Lawrence Livermore Lab. The basic Physics involved gives Heavy Ion Fusion an advantage over Laser Fusion because heavy ions have greater penetration power than photons. The Relativistic Heavy Ion Collider can be used as a Prototype Heavy Ion Fusion Reactor for the Large Hadron Collider.
基金support from the National Key Research and Development Program of China(No.2016YFA0300803)support from the Project of Shanghai HIgh repetition rate XFEL aNd Extreme light facility(SHINE)+13 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB16)support from the EPSRC,UK(Nos.EP/L013975 and EP/N022696/1)support from Extreme Light Infrastructure Nuclear Physics(ELI-NP) Phase IIa project co-financed by the Romanian Government and the European Union through the European Regional Development Fundsupport from EPSRC(No.EP/M018091/1)support from EPSRC(No.EP/M018555/1)STFC(Nos.ST/J002062/1 and ST/P002021/1)Horizon2020 funding from the European Research Council(ERC)(No.682399)support from the National Natural Science Foundation of China(Nos.11622547,11875319,11875091,11474360,and 11175255)the National Key Research and Development Program of China(No.2018YFA0404802)the Science Challenge Program(No.TZ2016005)the Hunan Province Science and Technology Program of China(No.2017RS3042)supported by the National Natural Science Foundation of China(Nos.11347028,11405083,and 11675075)UK Engineering and Physics Sciences Research Council(Nos.EP/G054940/1,EP/G055165/1,and EP/G056803/1)
文摘A new generation of high power laser facilities will provide laser pulses with extremely high powers of 10 petawatt(PW)and even 100 PW, capable of reaching intensities of 1023 W/cm^2 in the laser focus. These ultra-high intensities are nevertheless lower than the Schwinger intensity IS= 2.3×1029 W/cm^2 at which the theory of quantum electrodynamics(QED) predicts that a large part of the energy of the laser photons will be transformed to hard Gamma-ray photons and even to matter, via electron–positron pair production. To enable the investigation of this physics at the intensities achievable with the next generation of high power laser facilities, an approach involving the interaction of two colliding PW laser pulses is being adopted. Theoretical simulations predict strong QED effects with colliding laser pulses of 10 PW focused to intensities 10^(22) W/cm^2.
基金Supported by NSFC (10525525, 10775154, 10575114)Knowledge Innovation Funds of IHEP, CAS (H75452A0U2)
文摘An electron injector concept for a laser-plasma accelerator has been developed which relies on the use of counter propagating ultrashort laser pulses. In this paper, we use OOPIC the fully self-consistent, twodimensional, particle-in-cell code to make a parameter study to determine the bunches that can be obtained through collisions of two collinear laser pulses in uniform plasma. A series of simulations show that one can obtain a short (<10fs) bunch with its charge of about 15pC, and energy spread of about 15%. We also discussed the variation of the transverse spot size of the electron bunch and found the bunch would undergo the betatron oscillations.
基金supported by the National Natural Science Foundation of China (Nos.12275159, 12075140, and 12175117)100 Talents Program of CASShandong Provincial Natural Science Foundation (No. ZFJH202303)。
文摘Lambda polarization can be measured through its self-analyzing weak decay, making it an ideal candidate for studying spin effects in high-energy scattering. In lepton-nucleon deep inelastic scattering(DIS), Lambda polarization measurements can probe polarized parton distribution functions(PDFs) and polarized fragmentation functions(FFs). One of the most promising facilities for high-energy nuclear physics research is the proposed Electron-ion collider in China(EicC). As a next-generation facility, EicC is set to advance our understanding of nuclear physics to new heights. In this article, we study the Lambda production in electron-proton collisions at the EicC energy, in particular the reconstruction of Lambda based on the performance of the designed EicC detector. In addition, taking spontaneous transverse polarization as an example, we provide a theoretical prediction with a statistical projection based on one month of EicC data, offering valuable insights into future research prospects.
文摘In the standard fusion reactors, mainly tokamaks, the mechanical gain obtained is below 1. On the other hand, there are colliding beam fusion reactors, for which, the not neutral plasma and the space charge limit the number of fusions to a very small number. Consequently, the mechanical gain is extremely low. The proposed reactor is also a colliding beam fusion reactor, configured in Stellarator, using directed beams. D+/T+ ions are injected in opposition, with electrons, at high speeds, so as to form a neutral beam. All these particles turn in a magnetic loop in form of figure of “0” (“racetrack”). The plasma is initially non-thermal but, as expected, rapidly becomes thermal, so all states between non-thermal and thermal exist in this reactor. The main advantage of this reactor is that this plasma after having been brought up near to the optimum conditions for fusion (around 68 keV), is then maintained in this state, thanks to low energy non-thermal ions (≤15 keV). So the energetic cost is low and the mechanical gain (</span><i><span style="font-family:Verdana;">Q</span></i><span style="font-family:Verdana;">) is high (</span></span><span style="font-family:Verdana;">>></span><span style="font-family:Verdana;">1). The goal of this article is to study a different type of fusion reactor, its advantages (no net plasma current inside this reactor, so no disruptive instabilities and consequently a continuous working, a relatively simple way to control the reactor thanks to the particles injectors), and its drawbacks, using a simulator tool. The finding results are valuable for possible future fusion reactors able to generate massive energy in a cleaner and safer way than fission reactors.
基金Key Programs of Chinese Academy of Sciences(No.KJ95T-03)
文摘The Beijing spectrometer Ⅲ (BESⅢ) beam pipe is in the center of the BESⅢ, which is the detector of the upgrade project of Beijing electron and positron collider (BEPC Ⅱ). Electrons and positrons collide in the BESⅢ beam pipe. According to the demands of the BEPC Ⅱ, a key program of Chinese Academy of Sciences, the BESⅢ beam pipe is designed based on the finite elements analysis. The BESIII beam pipe is installed in the inner cylinder of the BESⅢ drift chamber. As a vacuum tube, the BESIII beam pipe is designed as 1 000 mm in length, 63 mm in inner diameter and 114 mm in outer diameter, respectively. The BESIII beam pipe consists of a central beryllium pipe cooled by EDM-1, the oil No.1 for electric discharge machining, and two extended copper pipes cooled by deionized water (DW). The three parts are jointed by vacuum welding. Factors taken into account in the design are as follows. ① The wall thickness of the central beryllium pipe should be designed as small as possible to reduce the multi-scattering and improve the particle momentum resolution. And the wall thickness of the extended copper pipe should be designed as large as possible to protect the detectors from the backgrounds. ②The BESⅢ beam pipe must be sufficiently cooled to avoid the damage and prevents its influence to the BESⅢ drift chamber (DC) operation. The inner surface temperature of the DC inner cylinder must be maintained at 293±2 K. ③ The magnetic permeability of the materials used in the BESⅢ beam pipe must be less than 1.05 H/m to avoid large magnetic field distortions. ④ The static pressure of the vacuum chamber of the BESⅢ beam pipe must be less than 800 μPa. The simulating results show that the designed structure of the BESⅢ beam pipe satisfies the requirements mentioned above. The structure design scheme is evaluated and adonted hv the headouarters of BEPCⅡ.
基金This work was supported by National Natural Science Foundation of China(11655003)Innovation Project of IHEP(542017IHEPZZBS11820)This work was supported in part by the CAS Center for Excellence in Particle Physics(CCEPP).
文摘Based on the LINAC of BEPCII, a high-polarized, high bightness, energy-tunable, monoenergetic laser compton backscattering (LCS)gamma-ray source is under construction at IHEP. The gamma-ray energy range is from 1 MeV to 111 MeV. It is a powerful and hopeful researchplatform to reveal the underlying physics of the nuclear, the basic particles and the vacuum or to check the exist basic physical models, quantumelectrodynamic (QED) theories. In the platform, a 1.064 mm Nd:YAG laser system and a 10.6 mm CO_(2) laser system are employed. All the triggersignals to the laser system and the electron control system are from the only reference clock at the very beginning of the LINAC to make sure thetemporal synchronization. Two optical transition radiation (OTR) targets and two charged-couple devices (CCD) are used to monitor and to alignthe electron beam and the laser beam. With the LCS gamma-ray source, it is proposed to experimentally check the gamma-ray calibrations, thephoton-nuclear physics, nuclear astrophysics and some basic QED phenomena.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10375017 and 10575029.
文摘The topcolour-assisted technicolour (TC2) model is an interesting dynamical theory among the various new physics models. We cMculate the total tt cross section and the relative correction of the TC2 model to the cross section at Tevatron Run Ⅱ and LHC. At the Tevatron Run Ⅱ, the cross section predicted by the standard model (SM) is consistent with the experimental data, and in most parameter spaces of the TC2 model, the relative correction of the TC2 model to the cross section is too small to be detectable. We find that the tt cross section is more sensitive to the parameters of the TC2 model at the LHC and the relative correction of the TC2 model to the cross section is over 10% in general. Such a value of the relative correction should be large enough to be detectable at the LHC. Therefore, it is promising to find the clue of the TC2 model via the tt production at the LHC.
基金supported by the National Natural Science Foundation of China (Nos. 11575214, 11527811, and 11805218)the Fermi Research Alliance+1 种基金LLCunder contract no. DE-AC02-07CH11359with the U.S. Department of Energy。
文摘The beam-beam effects in a hadron collider with an unprecedented energy scale were studied.These effects are strongly related to the attainable luminosity of the collider.Long-range interactions were identified as the major factor limiting the dynamic aperture,which is strongly dependent on the crossing angle,β*,and bunch population.Different mitigation methods of the beam-beam effects were addressed,with a focus on the compensation of long-range interactions by electric curren wires.The CEPC-SPPC project is a two-stage large circular collider,with a first-stage circular electron-positron collider(CEPC)and a second-stage super proton-proton collider(SPPC).The design of the SPPC aims to achieve a center-of-mass energy of 75 TeV and peak luminosity of approximately 1×10^(35) cm^(-2)s^(-1).We studied the beam-beam effects in the SPPC and tested the effectiveness of the mitigation methods.We found that with compensation using electric current wires,the dynamic aperture is at an acceptable level.Moreover,considering the significant emittance damping in this future proton-proton collider the beam-beam effects and compensation are more complicated and are studied using long-term tracking.It was found that with a smaller emittance,the head-on interactions with a crossing angle become more prominent in reducing the beam stability,and combined head-on and long-range compensation is needed to improve the beam quality.When the reduction in population owing to burnoff was included,it was found that the coupling between the transverse and longitudinal planes at smaller emittance is the main driving source of the instabilities.Thus,crab cavities and emittance control are also necessary than just the compensation of the long-range interactions to improve the beam stability.This study serves as an example for studying the beam-beam effects in future proton-proton colliders.
文摘The European organization for nuclear research(CERN)is planning a high performance particle collider by 2050,which will update the currently used Large Hadron Collider(LHC).The design of the new experiment facility includes the definition of a suitable communication infrastructure to support the future needs of scientists.The huge amount of data collected by the measurement devices call for a data rate of at least 1 Gb/s per node,while the need of timely control of instruments requires a low latency of the order of 0.01μs.Moreover,the main tunnel will be 100 km long,and will need appropriate coverage for voice and data traffic,in a special underground environment subject also to strong radiations.Reliable voice,data and video transmission in a tunnel of this length is necessary to ensure timely and localized intervention,reducing access time.In addition,using wireless communication for voice,control and data acquisition of accelerator technical systems could lead to a significant reduction in cabling costs,installation times and maintenance efforts.The communication infrastructure of the Future Circular Collider(FCC)tunnel must be able to circumvent the problems of radioactivity,omnipresent in the tunnel.Current technologies transceivers cannot transmit in such a severely radioactive environment.This is due to the immediate destruction of any active or passive equipment by radioactivity.The scope of this paper is to determine the feasibility of robust wireless transmission in an underground radioactive tunnel environment.The network infrastructure design to meet the demand will be introduced,and the performance of different wireless technologies will be evaluated.
基金Project supported by Yifang Wang’s Science Studio of the Ten Thousand Talents Project。
文摘To reduce the energy demand and operation cost for circular electron positron collider(CEPC), the high efficiency klystrons are being developed at Institute of High Energy Physics, Chinese Academy of Sciences. A 800-k W continuous wave(CW) klystron operating at frequency of 650-MHz has been designed. The results of beam–wave interaction simulation with several different codes are presented. The efficiency is optimized to be 65% with a second harmonic cavity in three-dimensional(3D) particle-in-cell code CST. The effect of cavity frequency error and mismatch load on efficiency of klystron have been investigated. The design and cold test of reentrant cavities are described, which meet the requirements of RF section design. So far, the manufacturing and high-power test of the first klystron prototype have been completed.When the gun operated at DC voltage of 80 k V and current of 15.4 A, the klystron peak power reached 804 k W with output efficiency of about 65.3% at 40% duty cycle. The 1-d B bandwidth is ±0.8 MHZ. Due to the crack of ceramic window, the CW power achieved about 700 kW. The high-power test results are in good agreement with 3D simulation.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11275088 and 11545012the Natural Science Foundation of Liaoning Scientific Committee under Grant No 2014020151
文摘The gauge extension of the standard model with the U(1)B-L+xy symmetry predicts the existence of a lightgauge boson Z′ with small couplings to ordinary fermions. We discuss its contributions to the muon anomalous magnetic moment αμ. Taking account of the constraints on the relevant free parameters, we further calculate the contributions of the light gauge boson Z′ to the Higgs-strahlung processes e+ e-→ZH and e+ e- →Z′H.
文摘Dark matter has been in the discussion of important theories for long time. As technology developed, more and more particles have been suggested to be the candidate of dark matter. This review will first discuss the observation evidence of the existence of dark matter in the aspect of cosmic microwave background, galaxy rotation curves, velocity dispersions and gravitational lensing. We then focus on some important collider researches, such as HL-LHC and CEPC about dark matter candidates: WIMPs. Finally, we extend the topic considering dark energy and inflation.
文摘It is proposed to place the arcs of an SLC-type facility inside the tunnel of a Future Circular Collider (FCC). Accelerated by a linear accelerator (linac), electron and positron beams would traverse the bending arcs in opposite directions and collide at centre-of-mass energies considerably exceeding those attainable at circular e+e−colliders. The proposed SLC-type facility would have the same luminosity as a conventional two-linace e+e−collider. Using an optical free-electron laser, the facility could be converted into a γγ collider. A superconducting L-band linac at the proposed facility may form a part of the injector chain for a 100-TeV proton collider in the FCC tunnel. The whole accelerator complex would serve as a source of e+e−, γγ, pp and ep interactions. The L-band linac could also be used to produce high-intensity neutrino, kaon and muon beams for fixed-target experiments, as well as X-ray free-electron laser (XFEL) photons for applications in material science and medicine.
文摘In many models stability of Dark Matter particles D is ensured by conservation of a new quantum number referred to as D -parity. Our models also contain charged D -odd particles D± with the same spin as D. (For more information,please refer to the PDF.)
文摘This is the second paper by the author describing versatile accelerator complexes that could be built at a Future Circular Collider (FCC) in order to produce e+e-, γγ and ep collisions. The facility described here features an ILC-based e+e- collider placed tangentially to the FCC tunnel. If the collider is positioned asymmetrically with respect to the FCC tunnel, electron (or positron) bunches could be accelerated by both linacs before they are brought into collision with the 50-TeV beams from the FCC proton storage ring (FCC-pp). The two linacs may also form a part of the injector chain for FCC-pp. The facility could be converted into a γγ collider or a source of multi-MW beams for fixed-target experiments.