Transverse impedances and collective instabilities in a heavy ion accelerator

Liu, J.; Jiang, Yang; Xia, J.W.; Yin, Da-Yu; Shen, Guodong; Li, P.; Wu, Bo; Ruan, S. N.; Hongwei, Zhao; Wang, G.; Dong, Zhihui; Wang, K. D.; Yao, Liping

doi:10.1103/physrevaccelbeams.21.064403

Cited by 11 publications

(4 citation statements)

References 8 publications

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“…In the synchrotron radiation sources, transverse beam instabilities include mode-coupling instability, coupled-bunch instability, head-tail instability and coasting beam instability etc. These beam instabilities may excites under specific conditions [4,5].…”

Section: Introductionmentioning

confidence: 99%

Measurement and parametric analysis of transverse coupled bunch instabilities for electron synchrotron radiation source Indus-2

Yadav¹,

Puntambekar²,

Varde³

2019

J. Inst.

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The performance of synchrotron radiation sources at high beam current gets often degraded due to the excitation of longitudinal and transverse coupled bunch instabilities (CBI). Hence, measurement of the coupled bunch instabilities may give insight into the performance of the machine, which in turn, may help supress these instabilities. Transverse coupled bunch instability is sensitive to the operating parameters of the accelerator such as betatron tune and sextupole magnet strength. In this paper, we report the measurement on transverse coupled bunch modes (CBM). The effect of betatron tune values and sextupole magnet strengths on transverse coupled bunch instability is discussed. For this study, betatron tune values and sextupole strengths are chosen in the vicinity of the routine operating points. With the help of this parametric study, an optimum operating point is identified in the beam operation with a minimum level of transverse coupled bunch instability. Further, an artificial neural network (ANN) is used to deduce a functional model between average transverse CBM levels and sextupole strengths. K: Accelerator modelling and simulations (multi-particle dynamics; single-particle dynamics); Coherent instabilities; Beam-line instrumentation (beam position and profile monitors; beam-intensity monitors; bunch length monitors); Instrumentation for particle accelerators and storage rings -low energy (linear accelerators, cyclotrons, electrostatic accelerators) 1Corresponding author.

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Section: Introductionmentioning

confidence: 99%

Measurement and parametric analysis of transverse coupled bunch instabilities for electron synchrotron radiation source Indus-2

Yadav¹,

Puntambekar²,

Varde³

2019

J. Inst.

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“…Besides, the bunch length (root-mean-square) of BRing is larger than 10 m and the interested frequency of broadband impedance is lower than 300 MHz [6]. Therefore, all the impedance spectrums are given with a wider frequency range from DC to 500 MHz to obtain a more accurate result.…”

Section: Transverse Broadband Impedance Model In the Bringmentioning

confidence: 99%

“…In the BRing, the total transverse broadband impedances are larger than the threshold impedance for the transverse mode-coupling instability [6]. The chromaticity, octupole magnets and feed-back system are often considered to mitigate the instability, but a large chromaticity will cause a large shift of incoherent tune, a large strength octupole magnet will cause the reduction of dynamic aperture and the design of feedback system is difficult.…”

Section: E Flanges and Transition Stepsmentioning

confidence: 99%

Transverse broadband impedance reduction techniques in a heavy ion accelerator

Chen

Zhu

Caspers

et al. 2020

Phys. Rev. Accel. Beams

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The transverse broadband impedances of major components in the BRing (booster ring) of HIAF (High Intensity Heavy-ion Accelerator Facility) are estimated using the analytical formulas or the wakefield solver in the CST Studio Suite. At low frequency, the transverse broadband impedance model of BRing is Z H 1 ðωÞ ¼ −417.14i kΩ=mðhorizontalÞ and Z V 1 ðωÞ ¼ −530.19i kΩ=mðverticalÞ, which are larger than the threshold impedance for the transverse mode-coupling instability. The ceramic rings in the vacuum chamber are the primary source of impedance. With a goal of mitigating the instability by reducing the impedance of ceramic rings, a high conductivity coating is discussed in detail. In addition, a prototype of ceramic rings-loaded thin-wall vacuum chamber is manufactured and the impedance measurements are performed. When ceramic rings are coated by 2 μm-copper, the CST simulation and experiment results show that the transverse broadband impedance of ceramic rings-loaded thin-wall vacuum chamber can be reduced from Z H 1¼ −291.69i kΩ=m and Z V 1 ðωÞ ¼ −352.37i kΩ=m to Z H 1 ðωÞ ¼ −46.16i kΩ=m and Z V 1 ðωÞ ¼ −64.56i kΩ=m. Furthermore, in this case the transverse broadband impedance model of BRing is reduced by more than 50% to Z H 1 ðωÞ ¼ −171.61i kΩ=m and Z V 1 ðωÞ ¼ −242.38i kΩ=m.

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“…The merits of the Bρ-IMS, namely high resolving power, ultimate sensitivity, short measurement time, broadband and background-free, make it the technique of choice for future storage ring mass spectrometry. The Bρ-IMS will be implemented at the Spectrometer Ring (SRing) [41] of the high-intensity Heavy-Ion Accelerator Facility (HIAF) [42,43], which is under construc- tion in China. It will also be used within the IL-IMA project [44,45] at the future FAIR facility in Germany [46,47], where two TOF detectors will be installed in a straight section of the Collector Ring CR [48,49].…”

mentioning

confidence: 99%

Bρ -defined isochronous mass spectrometry: An approach for high-precision mass measurements of short-lived nuclei

Wang¹,

Zhang²,

Zhang³

et al. 2022

Phys. Rev. C

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A novel technique for broadband high-precision mass measurements of short-lived exotic nuclides is reported. It is based on the isochronous mass spectrometry (IMS) and realizes simultaneous determinations of revolution time and velocity of short-lived stored ions at the cooler storage ring CSRe in Lanzhou. The new technique, named as the Bρ-defined IMS or Bρ-IMS, boosts the efficiency, sensitivity, and accuracy of mass measurements, and is applied here to measure masses of neutron-deficient f p-shell nuclides. In a single accelerator setting, masses of 46 Cr, 50 Fe and 54 Ni are determined with relative uncertainties of (5 -6)×10 −8 , thereby improving the input data for testing the unitarity of the Cabibbo-Kobayashi-Maskawa quark mixing matrix. This is the technique of choice for future high-precision measurements of the most rarely produced shortest-lived nuclides.

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Transverse impedances and collective instabilities in a heavy ion accelerator

Cited by 11 publications

References 8 publications

Measurement and parametric analysis of transverse coupled bunch instabilities for electron synchrotron radiation source Indus-2

Measurement and parametric analysis of transverse coupled bunch instabilities for electron synchrotron radiation source Indus-2

Transverse broadband impedance reduction techniques in a heavy ion accelerator

Bρ -defined isochronous mass spectrometry: An approach for high-precision mass measurements of short-lived nuclei

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