As an advanced 4^(th) generation synchrotron radiation facility,the Shenzhen Innovation Light-source Facility(SILF)storage ring is based on multi-bend achromat(MBA)lattices,enabling one to two orders of magnitude redu...As an advanced 4^(th) generation synchrotron radiation facility,the Shenzhen Innovation Light-source Facility(SILF)storage ring is based on multi-bend achromat(MBA)lattices,enabling one to two orders of magnitude reduction in beam emittance compared to the 3^(rd) generation storage ring.This significantly enhance the radiation brightness and coherence.The multipole magnets of many types for SILF storage ring are under preliminary design,which require high integral field homogeneity.As a result,a dedicated pole tip optimization procedure with high efficiency is developed for quadrupole and sextupole magnets with Opera-2D^(■)python script.The procedure considers also the 3D field effect which makes the optimization more straightforward.In this paper,the design of the quadrupole and sextupole magnets for SILF storage ring is first presented,followed by a detailed description of the implemented pole shape optimization method.展开更多
Purpose Design the sextupole precision mover for the Southern Advanced Photon Source that has requirements exceeding commercially available machines.Methods The design of the mover has been verified to meet the requir...Purpose Design the sextupole precision mover for the Southern Advanced Photon Source that has requirements exceeding commercially available machines.Methods The design of the mover has been verified to meet the requirements through a combination of static and dynamic simulations using ANSYS software,as well as relevant experimental testing.Results The mover we constructed has an absolute positioning error of 2 and 3µm,a maximum inclination angle of 1.55″and 5.67″in the horizontal and vertical motion directions respectively under a 400 kg load.Its vibration force transmission rate is 1.065.Conclusion The mover utilizes a non-coupled structure consisting of four layers of stainless steel plates,which exhibits good manufacturability.It is capable of achieving high precision and stability under a 400 kg load,meeting the requirements.展开更多
In a storage ring, asymmetry of the β function with momentum deviation is the main reason for asymmetry of the dynamic aperture. This paper applies simulation method based on AT code in Matlab to investigate sensitiv...In a storage ring, asymmetry of the β function with momentum deviation is the main reason for asymmetry of the dynamic aperture. This paper applies simulation method based on AT code in Matlab to investigate sensitivity of the β function beating and the tune shift to quadrupole field error with the presence of bending field error in the Shanghai Synchrotron Radiation Facility （SSRF） storage ring. Sextupole effect on the variation trend is analyzed. Dynamics of the lattice for working points close to and away from the second order structural resonance stop-band are compared. These results show that the β function beating with momentum deviation doesn＇t lie in the influence of the second order structural resonance stop-bands completely, but it is relevant to lattice structure.展开更多
The step-by-step chromaticity compensation method for chromatic sextupole optimization and dynamic aperture increase was proposed by E. Levichev and P. Piminov （E. Levichev and P. Piminov, 2006）. Although this metho...The step-by-step chromaticity compensation method for chromatic sextupole optimization and dynamic aperture increase was proposed by E. Levichev and P. Piminov （E. Levichev and P. Piminov, 2006）. Although this method can be used to enlarge the dynamic aperture of a storage ring, it has some drawbacks. In this paper, we combined this method with evolutionary computation algorithms, and proposed an improved version of this method. In the improved method, the drawbacks are avoided, and thus better optimization results can be obtained.展开更多
In this paper we present the physical design of the pulsed sextupole injection system for Beijing Advanced Photon Source （BAPS） with an ultralow emittance. The BAPS ring lattice is designed in such a way that two op...In this paper we present the physical design of the pulsed sextupole injection system for Beijing Advanced Photon Source （BAPS） with an ultralow emittance. The BAPS ring lattice is designed in such a way that two options of pulsed sextupole injection are allowed, i.e., with septum and pulsed sextupole in different drift spaces or in the same drift space. We give the magnetic parameters of the injection system and the optimal condition of the optical flmctions for both options. In addition, we find that the pulsed sextupole induces position-dependent dispersive effect and causes a non-ignorable effect on the injection efficiency in a storage ring with a relatively small acceptance, which should be well considered.展开更多
Background The China Spallation Neutron Source incorporates a rapid cycling synchrotron(RCS)that operates by accumulating protons at 80 MeV and subsequently accelerating them to 1.6 GeV within a time span of 20 ms.The...Background The China Spallation Neutron Source incorporates a rapid cycling synchrotron(RCS)that operates by accumulating protons at 80 MeV and subsequently accelerating them to 1.6 GeV within a time span of 20 ms.The beam is guided to striking the tungsten target for neutron source.Purpose As a space charge dominated machine,the RCS is subject to space charge effects and momentum spread,hereby influencing the tune spread.To address this issue,sextupole magnets,powered by two families of DC power supply,were initially employed to decrease the absolute value of chromaticity and to control the tune spread.The head-tail instability has been observed during the RCS beam commissioning.Method The beam tests and simulations were conducted,revealing that tuning the chromaticity proved to be an effective mitigation strategy.However,to achieve better control over the tune spread and further suppress the instability,the DC sextupole field has been upgraded to an AC sextupole field,aiming to provide dynamic for controlling the chromaticity over an acceleration cycle.Results and conclusion Thanks to the upgraded of AC field,the instability has been fully mitigated with beam power of 100 kW and the transmission in the RCS has been improved by~2%from 96 to 98%.With help of AC sextupole at present,the beam power in the RCS is increased to 140 kW.展开更多
Strong chromatic sextupoles used to compensate natural chromaticities in the third generation light source storage ring usually reduce dynamic aperture drastically. Many optimization methods can be used to find soluti...Strong chromatic sextupoles used to compensate natural chromaticities in the third generation light source storage ring usually reduce dynamic aperture drastically. Many optimization methods can be used to find solutions that provide large dynamic apertures. This paper discusses a new optimization approach of sextupole strengths with step-by-step procedure, which is applied in the SSRF storage ring, and a better solution is obtained. Investigating driving terms generated by the sextupoles in every step can analyze their convergences and guide the weight setting among different terms in object function of the single resonance approach based on the perturbation theory.展开更多
文摘As an advanced 4^(th) generation synchrotron radiation facility,the Shenzhen Innovation Light-source Facility(SILF)storage ring is based on multi-bend achromat(MBA)lattices,enabling one to two orders of magnitude reduction in beam emittance compared to the 3^(rd) generation storage ring.This significantly enhance the radiation brightness and coherence.The multipole magnets of many types for SILF storage ring are under preliminary design,which require high integral field homogeneity.As a result,a dedicated pole tip optimization procedure with high efficiency is developed for quadrupole and sextupole magnets with Opera-2D^(■)python script.The procedure considers also the 3D field effect which makes the optimization more straightforward.In this paper,the design of the quadrupole and sextupole magnets for SILF storage ring is first presented,followed by a detailed description of the implemented pole shape optimization method.
文摘Purpose Design the sextupole precision mover for the Southern Advanced Photon Source that has requirements exceeding commercially available machines.Methods The design of the mover has been verified to meet the requirements through a combination of static and dynamic simulations using ANSYS software,as well as relevant experimental testing.Results The mover we constructed has an absolute positioning error of 2 and 3µm,a maximum inclination angle of 1.55″and 5.67″in the horizontal and vertical motion directions respectively under a 400 kg load.Its vibration force transmission rate is 1.065.Conclusion The mover utilizes a non-coupled structure consisting of four layers of stainless steel plates,which exhibits good manufacturability.It is capable of achieving high precision and stability under a 400 kg load,meeting the requirements.
文摘In a storage ring, asymmetry of the β function with momentum deviation is the main reason for asymmetry of the dynamic aperture. This paper applies simulation method based on AT code in Matlab to investigate sensitivity of the β function beating and the tune shift to quadrupole field error with the presence of bending field error in the Shanghai Synchrotron Radiation Facility （SSRF） storage ring. Sextupole effect on the variation trend is analyzed. Dynamics of the lattice for working points close to and away from the second order structural resonance stop-band are compared. These results show that the β function beating with momentum deviation doesn＇t lie in the influence of the second order structural resonance stop-bands completely, but it is relevant to lattice structure.
基金Supported by National Natural Science Foundation of China(11175182,11175180)
文摘The step-by-step chromaticity compensation method for chromatic sextupole optimization and dynamic aperture increase was proposed by E. Levichev and P. Piminov （E. Levichev and P. Piminov, 2006）. Although this method can be used to enlarge the dynamic aperture of a storage ring, it has some drawbacks. In this paper, we combined this method with evolutionary computation algorithms, and proposed an improved version of this method. In the improved method, the drawbacks are avoided, and thus better optimization results can be obtained.
基金Supported by Special Fund of Chinese Academy of Sciences(H9293110TA)
文摘In this paper we present the physical design of the pulsed sextupole injection system for Beijing Advanced Photon Source （BAPS） with an ultralow emittance. The BAPS ring lattice is designed in such a way that two options of pulsed sextupole injection are allowed, i.e., with septum and pulsed sextupole in different drift spaces or in the same drift space. We give the magnetic parameters of the injection system and the optimal condition of the optical flmctions for both options. In addition, we find that the pulsed sextupole induces position-dependent dispersive effect and causes a non-ignorable effect on the injection efficiency in a storage ring with a relatively small acceptance, which should be well considered.
基金supported by the National Natural Science Foundation of China(Project:U1832210)the Guangdong Basic and Applied Basic Research Foundation,China(Project:2021B1515140007).
文摘Background The China Spallation Neutron Source incorporates a rapid cycling synchrotron(RCS)that operates by accumulating protons at 80 MeV and subsequently accelerating them to 1.6 GeV within a time span of 20 ms.The beam is guided to striking the tungsten target for neutron source.Purpose As a space charge dominated machine,the RCS is subject to space charge effects and momentum spread,hereby influencing the tune spread.To address this issue,sextupole magnets,powered by two families of DC power supply,were initially employed to decrease the absolute value of chromaticity and to control the tune spread.The head-tail instability has been observed during the RCS beam commissioning.Method The beam tests and simulations were conducted,revealing that tuning the chromaticity proved to be an effective mitigation strategy.However,to achieve better control over the tune spread and further suppress the instability,the DC sextupole field has been upgraded to an AC sextupole field,aiming to provide dynamic for controlling the chromaticity over an acceleration cycle.Results and conclusion Thanks to the upgraded of AC field,the instability has been fully mitigated with beam power of 100 kW and the transmission in the RCS has been improved by~2%from 96 to 98%.With help of AC sextupole at present,the beam power in the RCS is increased to 140 kW.
文摘Strong chromatic sextupoles used to compensate natural chromaticities in the third generation light source storage ring usually reduce dynamic aperture drastically. Many optimization methods can be used to find solutions that provide large dynamic apertures. This paper discusses a new optimization approach of sextupole strengths with step-by-step procedure, which is applied in the SSRF storage ring, and a better solution is obtained. Investigating driving terms generated by the sextupoles in every step can analyze their convergences and guide the weight setting among different terms in object function of the single resonance approach based on the perturbation theory.
