In order to perform the studies on a pulsed beam generation system based on a high intensity cyclotron, a test beam line with a pulsed beam generation for a 10 MeV compact cyclotron (CYCIAE-10) has been designed and c...In order to perform the studies on a pulsed beam generation system based on a high intensity cyclotron, a test beam line with a pulsed beam generation for a 10 MeV compact cyclotron (CYCIAE-10) has been designed and constructed at China Institute of Atomic Energy (CIAE). A 70 MHz continuous H- beam can be pulsed to the pulse length of less than 10 ns with a repetition rate of 4.4 MHz. The sine waveform with a frequency of 2.2 MHz is adopted for the chopper and a mesh structure with single drift and dual gaps is used for the 70 MHz buncher. A helical resonator is designed and constructed based on simulations and experiments on the RF matching for the chopper. A helical inductance loop that is exceptionally large of its kind and equipped with water cooling for the resonator has been successfully wound and a 500 W solid RF amplifier has been manufactured. A special measuring device has been designed, which can be used to measure both the DC beam and the pulsed beam. The required pulsed beam was obtained after pulsed beam tuning.展开更多
At least two bunchers are needed in the 3 MeV H^- Medium Energy Beam Transport （MEBT） line located between RFQ and DTL for the CSNS （China Spallation Neutron Source）. A nose-cone geometry has been adopted as the t...At least two bunchers are needed in the 3 MeV H^- Medium Energy Beam Transport （MEBT） line located between RFQ and DTL for the CSNS （China Spallation Neutron Source）. A nose-cone geometry has been adopted as the type of buncher cavity for its simplicity, higher impedance and lower risk of multipacting. By making use of the results got from the simulations on the buncher with two-dimension code SUPERFISH, the thermal and structural analyses have been carried out, the process and results to determine the resulting frequency shift due to thermal and structural distortion of the cavity are presented, the water-cooling channel position and the optimum cooling water temperature as well as the tuning method by adjusting the cooling water temperature when the cavity is out of resonance are also determined through the analyses.展开更多
BXERL is a proposal for a test facility （Beijing X-ray Energy Recovery Linac）, which requires its injector to provide an electron beam of 5 MeV, 77 pC/ bunch at a repetition rate of 130 MHz （average current of 10 m...BXERL is a proposal for a test facility （Beijing X-ray Energy Recovery Linac）, which requires its injector to provide an electron beam of 5 MeV, 77 pC/ bunch at a repetition rate of 130 MHz （average current of 10 mA）. In this paper, we present the design of the injector, which consists of a 500 kV photocathode DC gun equipped with a GaAs cathode preparation device, a 1.3 GHz normal conducting RF buncher, two solenoids, and one cryomodule containing two 1.3 GHz 2-cell superconducting RF cavities as the energy booster. The detailed beam dynamics show that the injector can generate electron bunches with a RMS normalized emittance of 1.49 πmm.mrad, a bunch length of 0.67 mm, a beam energy of 5 MeV and an energy spread of 0.72%.展开更多
A 150MeV injector electron linac for the SSRF is under construction at SINAP.This linac has been installed, commissioned and handed over to the SSRF during the period of 2006—2007.This paper describes the special nee...A 150MeV injector electron linac for the SSRF is under construction at SINAP.This linac has been installed, commissioned and handed over to the SSRF during the period of 2006—2007.This paper describes the special needs of an injector for a third generation synchrotron light source and the two specific modes of operation for this linac.The design results and the commissioning results for this linac are given in this paper.展开更多
Generally, a standard bunching system is composed by an SW pre-buncher, a TW buncher and a standard accelerating section. However, there is one way to simplify the whole system to some extent by using the hybrid bunch...Generally, a standard bunching system is composed by an SW pre-buncher, a TW buncher and a standard accelerating section. However, there is one way to simplify the whole system to some extent by using the hybrid buncher, which is a combined structure of the SW pre-buncher and the TW buncher. Here the beam dynamics studies on an S-band bunching system with the hybrid buncher is presented, and simulation results show that similar beam performance can be obtained at the linac exit by using this kind of bunching system rather than the standard one. In the meantime, the structure design of the hybrid buncher is also described. Furthermore, the standard accelerating section can also be integrated with the hybrid buncher, which can further simplify the usual bunching system and lower the construction cost.展开更多
The Radio Frequency Quadrupole (RFQ) accelerator invented by Kapchinskii and Tepliakov can focus, bunch, and accelerate charged-particle beams simultaneously. Typically, it operates at frequencies up to 500 MHz, for l...The Radio Frequency Quadrupole (RFQ) accelerator invented by Kapchinskii and Tepliakov can focus, bunch, and accelerate charged-particle beams simultaneously. Typically, it operates at frequencies up to 500 MHz, for low particle velocities ( β ). The first attempt to design cylindrical RFQ for electrons in the GHz region was done using 3 GHz at Frascati in 1990. In this paper, an analytical approximation of the electromagnetic field is given, and linearized in the beam region for a rectangular Electron Radio Frequency Quadrupole (ERFQ). The differences between the proton-RFQ and the electron-RFQ are discussed. Then, it will be shown that contrary to the quadrupoles for protons or heavy-ions, the ERFQ is suited for electron velocities in the range 0.5 - 0.7 c, and possible applications are given. Finally, it is illustrated, with numerical field computations that this approach gives sufficient accuracy at 10 GHz.展开更多
A new linear accelerator system,called the SSC-Linac injector,is being designed at HIRFL （the heavy ion research facility of Lanzhou）.As part of the SSC-Linac,the medium energy beam transport （MEBT） consists of se...A new linear accelerator system,called the SSC-Linac injector,is being designed at HIRFL （the heavy ion research facility of Lanzhou）.As part of the SSC-Linac,the medium energy beam transport （MEBT） consists of seven magnetic quadrupoles,a re-buncher and a diagnose box.The total length of this segment is about 1.75 m.The beam dynamics simulation in MEBT has been studied using the TRACK 3D particle-in-cell code,and the simulation result shows that the beam accelerated from the radio frequency quadrupole （RFQ） matches well with the acceptance of the following drift tube linac （DTL） in both the transverse and longitudinal phase spaces,and that most of the particles can be captured by the final sector focusing cyclotron for further acceleration.The longitudinal emittance of the RFQ and the longitudinal acceptance of the DTL was calculated in detail,and a multi-particle beam dynamics simulation from the ion source to the end of the DTL was done to verify the original design.展开更多
During the design process, multipacting effect has been taken into consideration using a 2D simulation code MultiPac and all of the corners are rounded to suppress the multipacting effect in the pill-box cavity. Howev...During the design process, multipacting effect has been taken into consideration using a 2D simulation code MultiPac and all of the corners are rounded to suppress the multipacting effect in the pill-box cavity. However, unexpected multipacting effect prevents the increase of the input power when the magnetic field of focusing coils is added after adequate conditioning and a novel method is adopted to suppress it by introducing extra coils to counteract the field. This paper focuses on the simulation of multipacting effect in different magnetic field configurations. The experimental observations and simulation results of multipacting effect are presented and details of the multipacting process are also analyzed.展开更多
We evaluated,for the first time in Turkey,the productivity of a feller buncher during clear-cut operations of two Brutian pine stands located in Canakkale,northwestern Turkey with different diameter classes and terrai...We evaluated,for the first time in Turkey,the productivity of a feller buncher during clear-cut operations of two Brutian pine stands located in Canakkale,northwestern Turkey with different diameter classes and terrain conditions.In the first stand with 24.6 cm average DBH,the feller buncher cut full trees and moved them to roadside.In the second stand with 34.3 cm average DBH,the feller buncher cut trees in two stages due to their larger diameters and the relatively steep and rough terrain conditions of the site.The effects of specific stand features,DBH and tree height measurements were assessed through statistical analysis in relation to productivity.The results indicate that the average productivity for the first stand was about 118 m^3h^-1,while it was about 80 m3h-1 in the second stand.Even though tree diameter and volume were higher in the second stand,productivity decreased by32.3%due to extra time spent on the two-stage cutting operation.The results revealed that harvesting operations should be planned carefully and the right equipment selected by accounting for different tree sizes,terrain conditions and machine specifications in order to better understand their effects on production.展开更多
A re-buncher with spiral arms for a heavy ion linear accelerator named as SSC-LINAC at HIRFL （the heavy ion research facility of Lanzhou） has been constructed. The re-buncher, which is used for beam longitudinal mod...A re-buncher with spiral arms for a heavy ion linear accelerator named as SSC-LINAC at HIRFL （the heavy ion research facility of Lanzhou） has been constructed. The re-buncher, which is used for beam longitudinal modulation and matching between the RFQ and DTL, is designed to be operated in continuous wave （CW） mode at the Medium-Energy Beam-Transport （MEBT） line to maintain the beam intensity and quality. Because of the longitudinal space limitation, the re-buncher has to be very compact and will be built with four gaps. We determined the key parameters of the re-buncher cavity from the simulations using Microwave Studio software, such as the resonant frequency, the quality factor Q and the shunt impedance. The detailed design of a 53.667 MHz spiral cavity and measurement results of its prototype will be presented.展开更多
A test beam line for pulsed beam generation for 10 MeV central region model (CRM) of a compact cyclotron is under construction at China Institute of Atomic Energy (CIAE).A 70MHz continuous H^- beam with the energy of ...A test beam line for pulsed beam generation for 10 MeV central region model (CRM) of a compact cyclotron is under construction at China Institute of Atomic Energy (CIAE).A 70MHz continuous H^- beam with the energy of dosens of keV or a hundred keV will be pulsed to a pulse length of less than 10ns with the repetition rate of 1—8MHz.A 70.487MHz buncher will be used to compress the DC beam into the RF phase acceptance of±30°of the CRM cyclotron. The 2.2MHz sine waveform will be used for the chopper.A pulse with the repetition rate of 4.4MHz and pulse length less than 10ns is expected after CRM cyclotron.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 10775186)
文摘In order to perform the studies on a pulsed beam generation system based on a high intensity cyclotron, a test beam line with a pulsed beam generation for a 10 MeV compact cyclotron (CYCIAE-10) has been designed and constructed at China Institute of Atomic Energy (CIAE). A 70 MHz continuous H- beam can be pulsed to the pulse length of less than 10 ns with a repetition rate of 4.4 MHz. The sine waveform with a frequency of 2.2 MHz is adopted for the chopper and a mesh structure with single drift and dual gaps is used for the 70 MHz buncher. A helical resonator is designed and constructed based on simulations and experiments on the RF matching for the chopper. A helical inductance loop that is exceptionally large of its kind and equipped with water cooling for the resonator has been successfully wound and a 500 W solid RF amplifier has been manufactured. A special measuring device has been designed, which can be used to measure both the DC beam and the pulsed beam. The required pulsed beam was obtained after pulsed beam tuning.
文摘At least two bunchers are needed in the 3 MeV H^- Medium Energy Beam Transport （MEBT） line located between RFQ and DTL for the CSNS （China Spallation Neutron Source）. A nose-cone geometry has been adopted as the type of buncher cavity for its simplicity, higher impedance and lower risk of multipacting. By making use of the results got from the simulations on the buncher with two-dimension code SUPERFISH, the thermal and structural analyses have been carried out, the process and results to determine the resulting frequency shift due to thermal and structural distortion of the cavity are presented, the water-cooling channel position and the optimum cooling water temperature as well as the tuning method by adjusting the cooling water temperature when the cavity is out of resonance are also determined through the analyses.
基金Supported by Creative Research Foundation of Institute of High Energy Physics (H85453G0U2)Key Project of Chinese National Programs for Fundamental Research and Development (2008CB817700)
文摘BXERL is a proposal for a test facility （Beijing X-ray Energy Recovery Linac）, which requires its injector to provide an electron beam of 5 MeV, 77 pC/ bunch at a repetition rate of 130 MHz （average current of 10 mA）. In this paper, we present the design of the injector, which consists of a 500 kV photocathode DC gun equipped with a GaAs cathode preparation device, a 1.3 GHz normal conducting RF buncher, two solenoids, and one cryomodule containing two 1.3 GHz 2-cell superconducting RF cavities as the energy booster. The detailed beam dynamics show that the injector can generate electron bunches with a RMS normalized emittance of 1.49 πmm.mrad, a bunch length of 0.67 mm, a beam energy of 5 MeV and an energy spread of 0.72%.
文摘A 150MeV injector electron linac for the SSRF is under construction at SINAP.This linac has been installed, commissioned and handed over to the SSRF during the period of 2006—2007.This paper describes the special needs of an injector for a third generation synchrotron light source and the two specific modes of operation for this linac.The design results and the commissioning results for this linac are given in this paper.
基金Supported by National Natural Science Foundation of China(11275222)
文摘Generally, a standard bunching system is composed by an SW pre-buncher, a TW buncher and a standard accelerating section. However, there is one way to simplify the whole system to some extent by using the hybrid buncher, which is a combined structure of the SW pre-buncher and the TW buncher. Here the beam dynamics studies on an S-band bunching system with the hybrid buncher is presented, and simulation results show that similar beam performance can be obtained at the linac exit by using this kind of bunching system rather than the standard one. In the meantime, the structure design of the hybrid buncher is also described. Furthermore, the standard accelerating section can also be integrated with the hybrid buncher, which can further simplify the usual bunching system and lower the construction cost.
文摘The Radio Frequency Quadrupole (RFQ) accelerator invented by Kapchinskii and Tepliakov can focus, bunch, and accelerate charged-particle beams simultaneously. Typically, it operates at frequencies up to 500 MHz, for low particle velocities ( β ). The first attempt to design cylindrical RFQ for electrons in the GHz region was done using 3 GHz at Frascati in 1990. In this paper, an analytical approximation of the electromagnetic field is given, and linearized in the beam region for a rectangular Electron Radio Frequency Quadrupole (ERFQ). The differences between the proton-RFQ and the electron-RFQ are discussed. Then, it will be shown that contrary to the quadrupoles for protons or heavy-ions, the ERFQ is suited for electron velocities in the range 0.5 - 0.7 c, and possible applications are given. Finally, it is illustrated, with numerical field computations that this approach gives sufficient accuracy at 10 GHz.
基金Supported by National Natural Science Foundation of China (10635090)
文摘A new linear accelerator system,called the SSC-Linac injector,is being designed at HIRFL （the heavy ion research facility of Lanzhou）.As part of the SSC-Linac,the medium energy beam transport （MEBT） consists of seven magnetic quadrupoles,a re-buncher and a diagnose box.The total length of this segment is about 1.75 m.The beam dynamics simulation in MEBT has been studied using the TRACK 3D particle-in-cell code,and the simulation result shows that the beam accelerated from the radio frequency quadrupole （RFQ） matches well with the acceptance of the following drift tube linac （DTL） in both the transverse and longitudinal phase spaces,and that most of the particles can be captured by the final sector focusing cyclotron for further acceleration.The longitudinal emittance of the RFQ and the longitudinal acceptance of the DTL was calculated in detail,and a multi-particle beam dynamics simulation from the ion source to the end of the DTL was done to verify the original design.
文摘During the design process, multipacting effect has been taken into consideration using a 2D simulation code MultiPac and all of the corners are rounded to suppress the multipacting effect in the pill-box cavity. However, unexpected multipacting effect prevents the increase of the input power when the magnetic field of focusing coils is added after adequate conditioning and a novel method is adopted to suppress it by introducing extra coils to counteract the field. This paper focuses on the simulation of multipacting effect in different magnetic field configurations. The experimental observations and simulation results of multipacting effect are presented and details of the multipacting process are also analyzed.
文摘We evaluated,for the first time in Turkey,the productivity of a feller buncher during clear-cut operations of two Brutian pine stands located in Canakkale,northwestern Turkey with different diameter classes and terrain conditions.In the first stand with 24.6 cm average DBH,the feller buncher cut full trees and moved them to roadside.In the second stand with 34.3 cm average DBH,the feller buncher cut trees in two stages due to their larger diameters and the relatively steep and rough terrain conditions of the site.The effects of specific stand features,DBH and tree height measurements were assessed through statistical analysis in relation to productivity.The results indicate that the average productivity for the first stand was about 118 m^3h^-1,while it was about 80 m3h-1 in the second stand.Even though tree diameter and volume were higher in the second stand,productivity decreased by32.3%due to extra time spent on the two-stage cutting operation.The results revealed that harvesting operations should be planned carefully and the right equipment selected by accounting for different tree sizes,terrain conditions and machine specifications in order to better understand their effects on production.
基金Supported by Pioneering and Interdisciplinary Research of Big Sciences (Y115210YQ0)
文摘A re-buncher with spiral arms for a heavy ion linear accelerator named as SSC-LINAC at HIRFL （the heavy ion research facility of Lanzhou） has been constructed. The re-buncher, which is used for beam longitudinal modulation and matching between the RFQ and DTL, is designed to be operated in continuous wave （CW） mode at the Medium-Energy Beam-Transport （MEBT） line to maintain the beam intensity and quality. Because of the longitudinal space limitation, the re-buncher has to be very compact and will be built with four gaps. We determined the key parameters of the re-buncher cavity from the simulations using Microwave Studio software, such as the resonant frequency, the quality factor Q and the shunt impedance. The detailed design of a 53.667 MHz spiral cavity and measurement results of its prototype will be presented.
文摘A test beam line for pulsed beam generation for 10 MeV central region model (CRM) of a compact cyclotron is under construction at China Institute of Atomic Energy (CIAE).A 70MHz continuous H^- beam with the energy of dosens of keV or a hundred keV will be pulsed to a pulse length of less than 10ns with the repetition rate of 1—8MHz.A 70.487MHz buncher will be used to compress the DC beam into the RF phase acceptance of±30°of the CRM cyclotron. The 2.2MHz sine waveform will be used for the chopper.A pulse with the repetition rate of 4.4MHz and pulse length less than 10ns is expected after CRM cyclotron.
