Stripping injection overcomes the limitations of Liouville's theorem and is widely used for beam injection and accumulation in high-intensity synchrotrons.The interaction between the stripping foil and beam is cru...Stripping injection overcomes the limitations of Liouville's theorem and is widely used for beam injection and accumulation in high-intensity synchrotrons.The interaction between the stripping foil and beam is crucial in the study of stripping injection,particularly in low-energy stripping injection synchrotrons,such as the XiPAF synchrotron.The foil thickness is the main parameter that affects the properties of the beam after injection.The thin stripping foil is reinforced with collodion during its installation.However,the collodion on the foil surface makes it difficult to determine its equivalent thickness,because the mechanical measurements are not sufficiently reliable or convenient for continuously determining foil thickness.We propose an online stripping foil thickness measurement method based on the ionization energy loss effect,which is suitable for any foil thickness and does not require additional equipment.Experimental studies were conducted using the XiPAF synchrotron.The limitation of this method was examined,and the results were verified by comparing the experimentally obtained beam current accumulation curves with the simulation results.This confirms the accuracy and reliability of the proposed method for measuring the stripping foil thickness.展开更多
The Xi'an Proton Application Facility(XiPAF)is a facility dedicated to the experimental simulation of the space radiation environment.The facility uses a compact synchrotron as its final-stage accelerator.The sync...The Xi'an Proton Application Facility(XiPAF)is a facility dedicated to the experimental simulation of the space radiation environment.The facility uses a compact synchrotron as its final-stage accelerator.The synchrotron can accelerate a proton beam from 7 to 230 MeV.Physical design results show that the radio frequency(RF) acceleration system should work in the frequency range of 1—6 MHz and provide a maximum voltage of >800 V.To dilute the strong space charge effect during the injection period,we also aim to achieve multiharmonic acceleration.A compact RF acceleration system loaded with magnetic alloy cores has been designed and developed to fulfill these requirements.The preliminary test results show that the system can work normally with a gap voltage of 800 V.With a further RF power upgrade,the voltage can be improved to >1:2 kV.展开更多
With the development of endoscopic therapy,argon plasma coagulation(APC)has been widely used by endoscopists.It has many advantages,such as simple to operate,low cost,and minimal invasiveness.Because of its capability...With the development of endoscopic therapy,argon plasma coagulation(APC)has been widely used by endoscopists.It has many advantages,such as simple to operate,low cost,and minimal invasiveness.Because of its capability of lesion ablation and hemostasis,APC has several indications in the gastrointestinal tract.One of them is esophageal varices.The aim of this review is to summarize the research on APC in this field to provide a reference for clinical practice.展开更多
The Xi’an proton accelerator facility synchrotron lattice has a systematic fourth-order resonance. The systematic octupole component in dipole magnets is found to have no adverse effect on the dynamic aperture in mul...The Xi’an proton accelerator facility synchrotron lattice has a systematic fourth-order resonance. The systematic octupole component in dipole magnets is found to have no adverse effect on the dynamic aperture in multiparticle tracking. The frequency map shows particles locked onto the 2v x 2v z-0 resonance. However, we will show that the instantaneous betatron tunes can vary widely around the resonance line for particles locked onto the resonance.展开更多
Tune ripple has a significant influence on beam spill ripple in RF-knockout(RF-KO)slow extraction.In this study,a model was proposed to explain how the tune ripple affects the beam spill in RF-KO slow extraction;conse...Tune ripple has a significant influence on beam spill ripple in RF-knockout(RF-KO)slow extraction.In this study,a model was proposed to explain how the tune ripple affects the beam spill in RF-KO slow extraction;consequently,a simulation was performed using the lattice of the Xi’an Proton Application Facility(XiPAF)synchrotron to verify the model.The simulation demonstrates that the tune ripple influences the beam spill in two ways.On the one hand,the tune ripple causes a direct fluctuation in the separatrix area,which induces beam spill ripple.On the other hand,the tune ripple influences the emittance growth rate in RF-knockout slow extraction.These two aspects simultaneously contribute to the beam spill ripple.展开更多
文摘Stripping injection overcomes the limitations of Liouville's theorem and is widely used for beam injection and accumulation in high-intensity synchrotrons.The interaction between the stripping foil and beam is crucial in the study of stripping injection,particularly in low-energy stripping injection synchrotrons,such as the XiPAF synchrotron.The foil thickness is the main parameter that affects the properties of the beam after injection.The thin stripping foil is reinforced with collodion during its installation.However,the collodion on the foil surface makes it difficult to determine its equivalent thickness,because the mechanical measurements are not sufficiently reliable or convenient for continuously determining foil thickness.We propose an online stripping foil thickness measurement method based on the ionization energy loss effect,which is suitable for any foil thickness and does not require additional equipment.Experimental studies were conducted using the XiPAF synchrotron.The limitation of this method was examined,and the results were verified by comparing the experimentally obtained beam current accumulation curves with the simulation results.This confirms the accuracy and reliability of the proposed method for measuring the stripping foil thickness.
文摘The Xi'an Proton Application Facility(XiPAF)is a facility dedicated to the experimental simulation of the space radiation environment.The facility uses a compact synchrotron as its final-stage accelerator.The synchrotron can accelerate a proton beam from 7 to 230 MeV.Physical design results show that the radio frequency(RF) acceleration system should work in the frequency range of 1—6 MHz and provide a maximum voltage of >800 V.To dilute the strong space charge effect during the injection period,we also aim to achieve multiharmonic acceleration.A compact RF acceleration system loaded with magnetic alloy cores has been designed and developed to fulfill these requirements.The preliminary test results show that the system can work normally with a gap voltage of 800 V.With a further RF power upgrade,the voltage can be improved to >1:2 kV.
文摘With the development of endoscopic therapy,argon plasma coagulation(APC)has been widely used by endoscopists.It has many advantages,such as simple to operate,low cost,and minimal invasiveness.Because of its capability of lesion ablation and hemostasis,APC has several indications in the gastrointestinal tract.One of them is esophageal varices.The aim of this review is to summarize the research on APC in this field to provide a reference for clinical practice.
基金supported by U.S.National Science Foundation(No.PHY-1504778)
文摘The Xi’an proton accelerator facility synchrotron lattice has a systematic fourth-order resonance. The systematic octupole component in dipole magnets is found to have no adverse effect on the dynamic aperture in multiparticle tracking. The frequency map shows particles locked onto the 2v x 2v z-0 resonance. However, we will show that the instantaneous betatron tunes can vary widely around the resonance line for particles locked onto the resonance.
基金supported by the National Natural Science Foundation of China(No.12075131)。
文摘Tune ripple has a significant influence on beam spill ripple in RF-knockout(RF-KO)slow extraction.In this study,a model was proposed to explain how the tune ripple affects the beam spill in RF-KO slow extraction;consequently,a simulation was performed using the lattice of the Xi’an Proton Application Facility(XiPAF)synchrotron to verify the model.The simulation demonstrates that the tune ripple influences the beam spill in two ways.On the one hand,the tune ripple causes a direct fluctuation in the separatrix area,which induces beam spill ripple.On the other hand,the tune ripple influences the emittance growth rate in RF-knockout slow extraction.These two aspects simultaneously contribute to the beam spill ripple.
