| Paper | Title | Other Keywords | Page |
|---|---|---|---|
| MOPEA024 | Effects of Insertion Devices in the High Field Lattice Structure of ILSF Storage Ring | insertion, insertion-device, quadrupole, radiation | 124 |
|
|||
|
We have studied effects of different insertion devices(IDs) in the high filed ILSF storage ring. Radiation from the IDs leads to change emittance and energy spread of the ring and magnetic field of them results to beta-beating, tune shift and shrink of dynamic aperture. This paper describes effects of the IDs on beam parameters of the high field lattice structure of ILSF storage ring and proposes the compensation method of these effects.
farhad.saeidi@ipm.ir |
|||
| MOPEA051 | Insertion Devices Influence on the Beam Dynamics at Siberia-2 Storage Ring | undulator, wiggler, insertion, insertion-device | 193 |
|
|||
| Siberia-2 is now running with 7.5 T wiggler and the installation of additional two 3 T SC wigglers is under consideration. Besides that the insertion of an undulator with very short period up to 7 mm is planed. We studied an influence of the insertion devices on the dynamic aperture using new computer code which permits to find an electron beam trajectory in ID by Runge-Kutta integrator. Using two independent approaches it was shown that ID introduces the nonlinear components of magnetic field which lead to significant decrease of dynamic aperture in vertical direction. Nonlinear components of ID magnetic field are shown. Results of numerical calculation of Siberia-2 dynamic aperture are presented as well. | |||
| MOPEA067 | Ultra-low Emittance Upgrade Options for Third Generation Light Sources | emittance, lattice, dipole, resonance | 237 |
|
|||
| The increasing efforts in the synchrotron light sources community toward the design of a diffraction limited source at multi-keV photon energy have eventually stimulated the existing facilities to investigate possible upgrade paths to higher photon brightness and lower emittances to maintain their competitiveness within the users’ community. We present a possible option for upgrading 3rd generation light sources based on a rebiuld of the arcs with MBA cells, using diamond as an example. Emphasis is given to the AP desing issues with a view to minimal changes to the machine layout, contained cost and minimal downtime | |||
| MOPWO026 | Investigation of Numerical Precision Issues of Long Term Single Particle Tracking | simulation, resonance, beam-beam-effects, HOM | 942 |
|
|||
|
Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. Long term single particle simplectic tracking is one of the most reliable tool to study the dynamic aperture of the circular accelerators. The present computational performance allows to explore the long term behaviour for an extended number of turns. It is well known that for instance single precision floating point arithmetic introduces too much numerical noise even after a moderate number of turns. In this paper we explore the artefacts of the double precision arithmetic that may be visible when the number of turns is in the order of 106, 107. |
|||
| TUPFI016 | Optimization of Triplet Quadrupoles Field Quality for the LHC High Luminosity Lattice at Collision Energy | target, quadrupole, lattice, luminosity | 1364 |
|
|||
|
Funding: Work supported by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404; and by the US DOE contract DE-AC02-76SF00515. For the high luminosity upgrade of the LHC (HL-LHC), the beta functions at two interaction points (IP) will be significantly reduced compared to the nominal LHC lattice. This will result in much higher peak beta functions in the inner triplet (IT) quadrupoles adjacent to these IPs. The consequences are a larger beam size in these quadrupoles, higher IT chromaticity, and stronger effects of the IT field errors on dynamic aperture (DA). The IT chromaticity will be compensated using the Achromatic Telescopic Squeezing scheme*. The increased IT beam size will be accommodated by installing large aperture Nb3Sn superconducting quadrupoles with 150 mm coil diameter. The field error tolerances in these magnets must satisfy the required acceptable DA while being reasonably close to realistically achievable field quality. Evaluation of the IT field errors was performed for the LHC upgrade layout version SLHCV3.01 with IT gradient of 123 T/m and IP collision beta functions of 15 cm in both planes. Dynamic aperture calculations were performed using SixTrack. Details of the optimization of the IT field errors are presented along with corrections to achieve the field quality specifications. * S. Fartoukh, “An Achromatic Telescopic Squeezing (ATS) Scheme for LHC Upgrade’’, in proceedings of IPAC11, p. 2088. |
|||
| TUPFI017 | Evaluation of Field Quality for Separation Dipoles and Matching Section Quadrupoles for the LHC High Luminosity Lattice at Collision Energy | quadrupole, dipole, lattice, simulation | 1367 |
|
|||
|
Funding: Work supported by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404; and by the US DOE contract DE-AC02-76SF00515. The high luminosity upgrade of the LHC (HL-LHC) lattice requires new larger aperture magnets to be installed in the low-beta interaction regions (IRs). These include Nb3Sn superconducting (SC) triplet quadrupoles, Nb-Ti SC separation dipoles D1 and D2, and SC Q4 quadrupoles. The upgrade significantly reduces the beta functions at these IRs, producing higher beta functions and larger beam size in these magnets, and requiring a larger aperture. The high beta functions also increase the impact of high order field errors in these new magnets on dynamic aperture (DA). Therefore, to maintain an acceptable DA, new specifications for the magnet field quality are required. Since the IR error effects at collision are dominated by the triplets, their field quality has been studied and specified first*. As a next step, the field errors were added to the D1 and D2 dipoles and Q4 quadrupoles while maintaining the triplet errors to specifications. The impact of the errors on DA has been determined in long term tracking simulations using SixTrack. The optimized field error specifications for the D1, D2 and Q4 magnets are presented. * Y. Nosochkov, Y. Cai, M-H. Wang, S. Fartoukh, M. Giovannozzi, R. de Maria, E. McIntosh, “Optimization of Triplet Field Quality for the LHC High Luminosity Lattice at Collision Energy”, IPAC 2013. |
|||
| TUPFI083 | Simulation Study of Head-on Beam-beam Compensation with Realistic RHIC Lattices | lattice, proton, resonance, simulation | 1541 |
|
|||
|
Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. We performed numerical simulations to study the effects of head-on beam-beam compensation with the realistic RHIC lattices. To better cancel the beam-beam resonance driving terms during half beam-beam compensation operation, the betatron phase advances between the interaction point IP8 and the center of the electron lens should be multiples of pi. for this purpose two shunt power supplies were added to the main quadrupole circuit buses in the arc between them. For the realistic beam-beam compensation lattices, the integer tunes are (27, 29) for the Blue ring and (29, 30) for the Yellow ring. The betatron phase advances between IP8 and the e-lens are (8pi,11pi) in the Blue ring and (11pi, 9pi) in the Yellow ring. Recent simulation results will be presented. |
|||
| TUPWO031 | Double-mini-beta Optics for the SSRF Storage Ring | optics, storage-ring, emittance, injection | 1943 |
|
|||
| The two long straight sections of the SSRF storage ring will be installed by dual canted in-vacuum insertion devices in the near future. In order to get high brightness and maintain good machine performance, the vertical beta function must be reduced by a triplet of quadrupole between the two source points, which is the so-called double-mini-beta optics. We have designed this kind of optics for SSRF, and the results are presented in this paper. | |||
| TUPWO033 | Effects Estimation of Superconducting Wiggler in SSRF | emittance, lattice, optics, quadrupole | 1946 |
|
|||
| Superconducting wiggler (SW) may greatly impact on the beam dynamics in a storage ring. The effects of a 4.5T SW has been studied in SSRF including impaction on the emittance and the energy spread. To keep an undegraded storage ring performance, a local achromatic lattice is considered. The combat between the damping effect of the SW and emittance growth of local achromatic lattice is the main concern of this paper. Other effects (tune shift, beta beating, dynamics aperture, etc.) with the SW are also simulated and optimized in this paper. | |||
| WEPEA008 | Influence of Higher Order Phase Slip Factor Contributions on Beam Loss during SIS-100 Proton Operation | quadrupole, sextupole, lattice, simulation | 2507 |
|
|||
| The projected FAIR synchrotron SIS-100 is envisaged to accelerate intense proton and heavy-ion beams. The maximum proton energy will be E=29 GeV. In order to stay below transition energy a special powering scheme of the quadrupoles has been introduced which provides a maximum transition gamma of 45.5. The resulting settings of the quadrupole focusing strengths generate large maxima of the horizontal beta and dispersion functions. In particle tracking simulation we observed beam loss caused by a large momentum spread in the deformed rf bucket close to transition. Application of the chromaticity correction sextupoles led to a reduction of the first-order phase slip factor term and of the beam losses. In this contribution we will analyze the effect of the sextupoles on the higher-order components of the phase slip factor. The rf bucket shape will be discussed as well as the transverse beam loss and possible longitudinal instabilities. | |||
| WEPEA021 | Influence of the Vacuum Chamber Limitation on Dynamic Aperture Calculations | vacuum, multipole, resonance, optics | 2543 |
|
|||
| In a storage ring the evaluation of the dynamic aperture taking into account the vacuum chamber limitation is more accurate and may display nonlinearities that could not be seen in the conventional absolute dynamic aperture calculations. This has been investigated in this paper and demonstrated in SESAME dynamic aperture case where taking into account the vacuum chamber uncovered the seriousness of a 5th order resonance mainly when errors like high order multipoles were introduced to the lattice. The destructive effect of the 5th order resonance has been avoided by changing the fractional part of the tunes. The problem has also been more investigated using the Frequency Map Analysis technique. | |||
| WEPEA022 | Analytical Estimations of the Dynamic Apertures of Beams with Momentum Deviation and Application in FFAG | sextupole, positron, simulation, lattice | 2546 |
|
|||
| Analytical formulae for estimating the dynamic apertures of synchrotron particles has been well established. Based on the standard mapping, we extend the analytical formulae of dynamic aperture for off-momentum particles in circular accelerator. And we compare the analytical results with the simulation ones in the BEPC-II positron ring lattice under some conditions. What's more, we give the analytical formulae of dynamic aperture for FFAG in the similar way. | |||
| WEPEA025 | Chromatic Sextupole Pair Optimization Methods for Enlarging Dynamic Aperture | sextupole, lattice, focusing, storage-ring | 2555 |
|
|||
|
Based on the step-by-step chromaticity compensation method [1] and artificial intelligence algorithms, we propose new numerical methods, called chromatic sextupole pair optimization methods, for enlarging the dynamic aperture of electron storage rings. In the new methods, the decision variables related to chromatic sextupole pairs are optimized using artificial intelligence algorithms to enlarge the dynamic aperture. We demonstrate that the new methods are equivalent to the recently used numerical method, in which the decision variables, sextupole strengths, are optimized using artificial intelligence algorithms.
[1] E. Levichev, P. Piminov, Proceedings of EPAC 2006, p. 2116. |
|||
| WEPEA045 | Specifications of the Field Quality at Injection Energy of the New Magnets for the HL-LHC Upgrade Project | injection, multipole, simulation, optics | 2603 |
|
|||
|
Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. The HL-LHC project relies on new magnet designs and technologies to achieve very small β* values. In particular, Nb3Sn magnets show large allowed multipole imperfections at low current. These field errors may have a non-negligible impact on the dynamic aperture and beam life time in the HL-LHC, also because of the smaller-than-nominal β* values foreseen IR1 and IR5 at injection energy, which aims at decreasing the dynamic range of the squeeze and therefore contributing to optimize the turn around time. The paper describes an analysis of the machine performance based on analytical estimates and tracking simulations with the goal of providing field quality specifications for the new magnets. |
|||
| WEPEA046 | Experimental Observations from the LHC Dynamic Aperture Machine Development Study in 2012 | beam-losses, emittance, injection, octupole | 2606 |
|
|||
|
In view of improving the understanding of the behaviour of the dynamic aperture and to benchmark the numerical simulations performed so far, two experimental sessions have been scheduled at the LHC. The observations of the first sessions have been reported elsewhere[1], while in this paper the latest observations in terms of beam currents, blm losses and beam sizes will be described. The octupolar spool pieces have been used to artificially reduce the dynamic aperture and then induced slow beam losses. Alternating signs have been used in order to probe different configurations. Finally, scans over the strength of the decapolar spool pieces have been performed too.
[1] M. Giovannozzi et al., “First Experimental Observations from the LHC Dynamic Aperture Experiment”, in proceedings of IPAC12, p. 1362 |
|||
| WEPEA047 | Dynamic Aperture Performance for Different Collision Optics Scenarios for the LHC Luminosity Upgrade | optics, multipole, luminosity, injection | 2609 |
|
|||
|
Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. The ATS[1] optics solution for the HL-LHC offers the possibility of different collision optics, with a β* as small as 10 cm in both transverse planes, or with a β* aspect ratio of up to 4 pushing β* to even smaller value (5cm) in the parallel separation plane while relaxing it (20 cm) in the crossing plane. The latter configuration features two possible options for alternated orientations of the crossing plane in the two high luminosity insertions, both considered in this study. In this paper we study the impact of few selected field imperfection models of the new magnets foreseen for the upgrade through tracking simulations and scaling laws. [1] S. Fartoukh, ‘’An Achromatic Telescopic Squeezing (ATS) Scheme for LHC Upgrade’’, in proceedings of IPAC11, p. 2088. |
|||
| WEPEA050 | Analysis of Possible Functional Forms of the Scaling Law for Dynamic Aperture as a Function of Time | luminosity, beam-losses, simulation, lattice | 2618 |
|
|||
|
Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. In recent studies, the evolution of the dynamic aperture with time has been fitted with a simple scaling law based on a limited number of free parameters. In this paper, different approaches to improve the numerical stability of the fit are presented, together with a new functional form. The results are discussed in details and applied to a set of numerical simulations for the LHC. |
|||
| WEPEA071 | Performance Limitations in the Lhc Due to Parasitic Beam-Beam Encounters - Parameter Dependence, Scaling, and Pacman Effects | beam-beam-effects, emittance, luminosity, target | 2672 |
|
|||
| We studied possible limitations due to the long-range beam-beam effects in the LHC. With a large number of bunches and collisions in all interaction points, we have reduced the crossing angles (separation) to enhance long-range beam-beam effects to evaluate their influence on dynamic aperture and losses. Different β*, number of bunches and intensities have been used in several dedicated experiments and allow the test of the expected scaling laws. | |||
| WEPEA077 | Applying the 'Simple Accelerator Modelling in Matlab' (SAMM) Code to High Luminosity LHC Upgrade | proton, dipole, kicker, quadrupole | 2690 |
|
|||
| The "Simple Accelerator Modelling in Matlab" (SAMM) code is a set of Matlab routines for modelling beam dynamics in high energy particle accelerators. It includes a set of CUDA codes that can be run on a Graphics Processor Unit. These can be called from SAMM and can speed up tracking simulations by 100 times. To make use of this potential for the computationally intensive LHC upgrade simulations, we have developed additional Matlab and CUDA routines to simulate the full set of elements that are present in the Large Hadron Collider. We present the results of applying these codes to dynamic aperture calculations. These results are benchmarked against PTC and MADX. | |||
| WEPEA081 | Local 3Qy Betatron Resonance Correction in the 2012 RHIC 250 GeV Run | sextupole, resonance, proton, betatron | 2696 |
|
|||
|
Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In this article we performed numerical simulations to correct the local vertical third order betatron resonance 3Qy in the interaction regions in the Yellow ring for the 2012 RHIC 250~GeV polarized proton run. Considering the main sources of skew sextupoles are located in the interaction regions, we used local bump methods to minimize their contributions to the global 3Qy resonance driving term. Two kinds of correction orbit bumps are tested and the dynamic apertures with these correction strengths are calculated and compared. |
|||