In conventional slowness-time coherence(STC)method,slowness and time need to be searched at the same time,which limits the precision and lowers the efficiency.The dichotomy method combined with slowness-time coherence...In conventional slowness-time coherence(STC)method,slowness and time need to be searched at the same time,which limits the precision and lowers the efficiency.The dichotomy method combined with slowness-time coherence algorithm aims to enhance the efficiency of data processing and to improve the precision.The algorithm changes the searching pattern of conventional slowness-time coherence method to acquire the slowness of component waves in array acoustic logging data.Based on energy ratio of short time window versus long time window and slowness-time coherence method,the algorithm first acquires the arrivals of the component waves using energy ratio of short time window versus long time window method.It then uses the calculated results as the arrivals in conventional slowness-time coherence method,so the slowness-time two-dimensional searching process is simplified to slowness searching process.Based on dichotomy method,the searching pattern is further optimized in replace of the ergodic searching pattern in conventional slowness-time coherence method,which means that as the iteration proceeds,the current searching interval is reduced to half of the former,so the number of searching times is decreased.The dichotomy method combined with slowness-time coherence algorithm is applied to well L in the data processing.Compared with conventional slowness-time coherence method,for compressional wave,the searching efficiency of the algorithm is 4.53 times better,while for Stoneley wave,the searching efficiency is 1.85 times better.Compared with conventional logging data,the average absolute error of the results of the dichotomy method combined with slowness-time coherence algorithm is 1.14μs/ft smaller than that of the conventional method,while the average relative error is 1.2 percent lower.The dichotomy method combined with slowness-time coherence algorithm shows good results in its application,which can enhance the processing efficiency remarkably while getting reliable results at the same time.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
Because of its excellent dose distribution,proton therapy is becoming increasingly popular in the medical application of cancer treatment.A synchrotron-based proton therapy facility was designed and constructed in Sha...Because of its excellent dose distribution,proton therapy is becoming increasingly popular in the medical application of cancer treatment.A synchrotron-based proton therapy facility was designed and constructed in Shanghai.The synchrotron,beam delivery system,and other technical systems were commissioned and reached their expected performances.After a clinical trial of 47 patients was finished,the proton therapy facility obtained a registration certificate from the National Medical Products Administration.The characteristics of the accelerator and treatment systems are described in this article.展开更多
A 3D stereotomography algorithm, which is derived from the 3D Cartesian coordinate, is applied for the first time to the deep-sea data acquired in the LH area, South China Sea, to invert a macro velocity model for pre...A 3D stereotomography algorithm, which is derived from the 3D Cartesian coordinate, is applied for the first time to the deep-sea data acquired in the LH area, South China Sea, to invert a macro velocity model for pre-stack depth migration. The successful implementation of stereotomography is highly dependent on the correct extraction of slowness components and the proper application of regularization terms. With the help of the structure tensor algorithm, a high-quality 3D stereotomography data space is achieved in a very efficient manner. Then, considering that the horizontal slowness in cross-line direction is usually unavailable for 3D narrow-azimuth data, the regularization terms must be enhanced to guarantee a stable convergence of the presented algorithm. The inverted model serves as a good model for the 3D pre-stack depth migration. The synthetic and real data examples demonstrated the robustness and effectiveness of the presented algorithm and the related schemes.展开更多
A compact facility for cancer therapy has been designed and is presently under construction. A slow beam extraction system using the RF-Knock Out method and 3rd-order resonance is adopted in the synchrotron of this fa...A compact facility for cancer therapy has been designed and is presently under construction. A slow beam extraction system using the RF-Knock Out method and 3rd-order resonance is adopted in the synchrotron of this facility. Eight sextupoles are used, four of them are for correcting the chromaticity and the rest for driving the 3rd-order resonance. In order to save the aperture of vacuum chamber, a 3-magnet bump is adopted during the extraction process. The extraction phase space map and the last 3 turns’ particle trajectory before extraction are given. The matching betatron functions with HEBT （high energy beam transport） are also presented.展开更多
Based on the optimized design of the lattice for therapy synchrotron and considering the requirement of radiation therapy, the third order resonant extraction is adopted. Using the momentum-amplitude selection method,...Based on the optimized design of the lattice for therapy synchrotron and considering the requirement of radiation therapy, the third order resonant extraction is adopted. Using the momentum-amplitude selection method, the extraction system is designed and optimized. An extraction efficiency of more than 97% and a momentum spread less than 0.11% are obtained.展开更多
This paper presents the design of a compact proton synchrotron, including lattice structure, injection system and extraction system, for radiation applications. The lattice is based on a DBFO cell and shows good prope...This paper presents the design of a compact proton synchrotron, including lattice structure, injection system and extraction system, for radiation applications. The lattice is based on a DBFO cell and shows good properties like small β_（max） and decent kick arm. Radiation applications require relative strong and continuous beam,so we propose strip injection and resonance extraction for the design. A phase space painting scheme is designed and simulated by ORBIT. The scheme achieves good uniformity in phase space. The extraction system is designed and optimized by multi-particle tracking.展开更多
A proton therapy facility based on a linac injector and a slow-cycling synchrotron is proposed. To obtain good treatments for different cancer types, both the spot scanning method and the double-scattering method are ...A proton therapy facility based on a linac injector and a slow-cycling synchrotron is proposed. To obtain good treatments for different cancer types, both the spot scanning method and the double-scattering method are adopted in the facility, whereas the nozzles include both gantry and fixed beam types. The proton accelerator chain includes a synchrotron of 250 MeV in maximum energy, an injector of 7 MeV consisting of an RFQ and a DTL linac, with a repetition rate of 0.5 Hz. The slow extraction using the third-order resonance and together with the RFKO method is considered to be a good method to obtain a stable and more-or-less homogenous beam spill. To benefit the spot scanning 200 between 60 MeV and 230 MeV. A new method method, the extraction energy can be as many as about - the emittance balancing technique of using a solenoid or a quadrupole rotator is proposed to solve the problem of unequal emittance in the two transverse planes with a beam slowly extracted from a synchrotron. The facility has been designed to keep the potential to be upgraded to include the carbon therapy in the future.展开更多
Using the China Spallation Neutron Source（CSNS） linac as the injector, a 500 MeV proton synchrotron is proposed for multidisciplinary applications, such as biology, material science and proton therapy. The synchrotr...Using the China Spallation Neutron Source（CSNS） linac as the injector, a 500 MeV proton synchrotron is proposed for multidisciplinary applications, such as biology, material science and proton therapy. The synchrotron will deliver proton beam with energy from 80 MeV to 500 MeV. A compact lattice design has been worked out, and all the important beam dynamics issues have been investigated. The 80 MeV H-beam is stripped and injected into the synchrotron by using multi-turn injection. In order to continuously extraction the proton with small beam loss,an achromatic structure is proposed and a slow extraction method with RF knock-out is adopted and optimized.展开更多
基金Supported by the National High Technology Research and Development of China(863 Programme)(No.2013AA092501)
文摘In conventional slowness-time coherence(STC)method,slowness and time need to be searched at the same time,which limits the precision and lowers the efficiency.The dichotomy method combined with slowness-time coherence algorithm aims to enhance the efficiency of data processing and to improve the precision.The algorithm changes the searching pattern of conventional slowness-time coherence method to acquire the slowness of component waves in array acoustic logging data.Based on energy ratio of short time window versus long time window and slowness-time coherence method,the algorithm first acquires the arrivals of the component waves using energy ratio of short time window versus long time window method.It then uses the calculated results as the arrivals in conventional slowness-time coherence method,so the slowness-time two-dimensional searching process is simplified to slowness searching process.Based on dichotomy method,the searching pattern is further optimized in replace of the ergodic searching pattern in conventional slowness-time coherence method,which means that as the iteration proceeds,the current searching interval is reduced to half of the former,so the number of searching times is decreased.The dichotomy method combined with slowness-time coherence algorithm is applied to well L in the data processing.Compared with conventional slowness-time coherence method,for compressional wave,the searching efficiency of the algorithm is 4.53 times better,while for Stoneley wave,the searching efficiency is 1.85 times better.Compared with conventional logging data,the average absolute error of the results of the dichotomy method combined with slowness-time coherence algorithm is 1.14μs/ft smaller than that of the conventional method,while the average relative error is 1.2 percent lower.The dichotomy method combined with slowness-time coherence algorithm shows good results in its application,which can enhance the processing efficiency remarkably while getting reliable results at the same time.
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.
文摘Because of its excellent dose distribution,proton therapy is becoming increasingly popular in the medical application of cancer treatment.A synchrotron-based proton therapy facility was designed and constructed in Shanghai.The synchrotron,beam delivery system,and other technical systems were commissioned and reached their expected performances.After a clinical trial of 47 patients was finished,the proton therapy facility obtained a registration certificate from the National Medical Products Administration.The characteristics of the accelerator and treatment systems are described in this article.
基金funded by China Natural Science Foundation(Nos.41574098 and 41630964)China key specialized project(No.2016ZX05026-001-03)
文摘A 3D stereotomography algorithm, which is derived from the 3D Cartesian coordinate, is applied for the first time to the deep-sea data acquired in the LH area, South China Sea, to invert a macro velocity model for pre-stack depth migration. The successful implementation of stereotomography is highly dependent on the correct extraction of slowness components and the proper application of regularization terms. With the help of the structure tensor algorithm, a high-quality 3D stereotomography data space is achieved in a very efficient manner. Then, considering that the horizontal slowness in cross-line direction is usually unavailable for 3D narrow-azimuth data, the regularization terms must be enhanced to guarantee a stable convergence of the presented algorithm. The inverted model serves as a good model for the 3D pre-stack depth migration. The synthetic and real data examples demonstrated the robustness and effectiveness of the presented algorithm and the related schemes.
基金Supported by State Key Development Program of Basic Research of China (2010CB834204)
文摘A compact facility for cancer therapy has been designed and is presently under construction. A slow beam extraction system using the RF-Knock Out method and 3rd-order resonance is adopted in the synchrotron of this facility. Eight sextupoles are used, four of them are for correcting the chromaticity and the rest for driving the 3rd-order resonance. In order to save the aperture of vacuum chamber, a 3-magnet bump is adopted during the extraction process. The extraction phase space map and the last 3 turns’ particle trajectory before extraction are given. The matching betatron functions with HEBT （high energy beam transport） are also presented.
基金Supported by Key Equipment R & D Fund of CAS (0713040YZ0)
文摘Based on the optimized design of the lattice for therapy synchrotron and considering the requirement of radiation therapy, the third order resonant extraction is adopted. Using the momentum-amplitude selection method, the extraction system is designed and optimized. An extraction efficiency of more than 97% and a momentum spread less than 0.11% are obtained.
文摘This paper presents the design of a compact proton synchrotron, including lattice structure, injection system and extraction system, for radiation applications. The lattice is based on a DBFO cell and shows good properties like small β_（max） and decent kick arm. Radiation applications require relative strong and continuous beam,so we propose strip injection and resonance extraction for the design. A phase space painting scheme is designed and simulated by ORBIT. The scheme achieves good uniformity in phase space. The extraction system is designed and optimized by multi-particle tracking.
文摘A proton therapy facility based on a linac injector and a slow-cycling synchrotron is proposed. To obtain good treatments for different cancer types, both the spot scanning method and the double-scattering method are adopted in the facility, whereas the nozzles include both gantry and fixed beam types. The proton accelerator chain includes a synchrotron of 250 MeV in maximum energy, an injector of 7 MeV consisting of an RFQ and a DTL linac, with a repetition rate of 0.5 Hz. The slow extraction using the third-order resonance and together with the RFKO method is considered to be a good method to obtain a stable and more-or-less homogenous beam spill. To benefit the spot scanning 200 between 60 MeV and 230 MeV. A new method method, the extraction energy can be as many as about - the emittance balancing technique of using a solenoid or a quadrupole rotator is proposed to solve the problem of unequal emittance in the two transverse planes with a beam slowly extracted from a synchrotron. The facility has been designed to keep the potential to be upgraded to include the carbon therapy in the future.
文摘Using the China Spallation Neutron Source（CSNS） linac as the injector, a 500 MeV proton synchrotron is proposed for multidisciplinary applications, such as biology, material science and proton therapy. The synchrotron will deliver proton beam with energy from 80 MeV to 500 MeV. A compact lattice design has been worked out, and all the important beam dynamics issues have been investigated. The 80 MeV H-beam is stripped and injected into the synchrotron by using multi-turn injection. In order to continuously extraction the proton with small beam loss,an achromatic structure is proposed and a slow extraction method with RF knock-out is adopted and optimized.
