Field stabilization studies for a radio frequency quadrupole accelerator

Gaur, Rahul; Kumar, Vinay

doi:10.1088/1748-0221/9/07/t07003

Cited by 4 publications

(3 citation statements)

References 11 publications

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“…For BISOL RFQ, the nearest mode to operating mode is TE 111 , the corresponding mode separation is only 0.5 MHz. In general, the typical methods for increasing the mode separation are π-mode stabilizing loops (PSLs) and dipole-mode stabilization rods (DSRs) [8,9,[25][26][27][28], as shown in figure 24. Figure 25 shows the sensitivity of the mode separation to the variations of PSLs distance and DIPs length.…”

Section: Mode Separationmentioning

confidence: 99%

Design and study of a continuous wave RFQ for the BISOL high intensity deuteron driver linac

Li¹,

Wang²,

Lu³

et al. 2020

J. Inst.

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A high intensity four-vane continue wave (cw) RFQ for the Beijing Isotope Separation On-Line (BISOL) high intensity deuteron driver linac has been designed. This RFQ will accelerate the 25 mA cw deuteron beam the 3.0 MeV with an operating frequency of 162.5 MHz. Three beam dynamics design schemes based on different strategies have been proposed and detailed comparisons, including tolerance study and error analysis, are performed to evaluate them. The final design of RFQ can achieve the requirements with a length of 5.29 m and the transmission of 99.1%. The inter-vane voltage is ramped from 60 kV to 75 kV and the maximum Kilpatrick factor is 1.42, which is very modest and beneficial to cw operation mode. The RFQ electromagnetic design is carried out based on the full-length 3D model, including vane modulation, undercuts, π-mode stabilization rods (PSLs) and tuners. The requirements of correct work frequency and voltage ramp are fulfilled by varying vane width and adjusting undercuts. In addition, the π-mode stabilization rods (PSLs) are inserted and optimized to increase mode separation and enhance voltage stabilization. The rf power loss and effective shunt impendence are 118 kW and 210 kΩ⋅m, respectively. In addition, multi-physics analysis of the cavity, based on the electromagnetic codes CST MWS, HFSS and ANSYS, has been carried out to check the cooling system, the temperature rise and deformation of the cavity, as well as the frequency shift in the cw operation. Finally, the frequency sensitivities to cooling water temperature are studied to obtain water temperature tuning coefficients, which will be used for fine tuning of the RFQ cavity during operation.

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Section: Mode Separationmentioning

confidence: 99%

Design and study of a continuous wave RFQ for the BISOL high intensity deuteron driver linac

Li¹,

Wang²,

Lu³

et al. 2020

J. Inst.

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“…The quadrupole and dipole mode frequencies can be very close in a four-vane RFQ as the length of the structure increases, which introduces the possibility of accidental degeneracy between the operating quadrupole mode and the dipole family [9]. Enhanced dipole-to-quadrupole mode separation can make the RFQ less sensitive to dimensional construction errors and strengthen its field stabilization [24]. Various methods have been devised to increase the mode separation, including vane coupling rings [25], dipole separation rods (DSR) [26,27], π-mode stabilizer loops (PISL) [28,29] and asymmetric four-vane RFQ [30].…”

Section: Double-dipole Four-vane Structurementioning

confidence: 99%

Novel deuteron RFQ design with trapezoidal electrodes and double dipole four-vane structure

Wang

et al. 2020

J. Inst.

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“…Then, the faces of the covered profiles were joined using loft operation in CST modeler in order to model the vane in the RMS and FFS sections. Various parameters need to be optimized for the design of cutbacks [24]. Here, b is the radius of the beam hole at the end-plate, t is the thickness of the end-plate, g is the gap between the vane and the end-plate, d is the undercut depth up to which the vane is removed, h 2 and h 3 are the heights of the vane at the starting and the end of the undercut respectively, and h 1 is the full height of the RFQ vane from the beam axis.…”

Section: Vane-end Cutback Designmentioning

confidence: 99%

Beam dynamics and electromagnetic studies of a 3 MeV, 325 MHz radio frequency quadrupole accelerator

Gaur

Kumar

2018

EPJ Nuclear Sci. Technol.

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We present the beam dynamics and electromagnetic studies of a 3 MeV, 325 MHz H− radio frequency quadrupole (RFQ) accelerator for the proposed Indian Spallation Neutron Source project. We have followed a design approach, where the emittance growth and the losses are minimized by keeping the tune depression ratio larger than 0.5. The transverse cross-section of RFQ is designed at a frequency lower than the operating frequency, so that the tuners have their nominal position inside the RFQ cavity. This has resulted in an improvement of the tuning range, and the efficiency of tuners to correct the field errors in the RFQ. The vane-tip modulations have been modelled in CST-MWS code, and its effect on the field flatness and the resonant frequency has been studied. The deterioration in the field flatness due to vane-tip modulations is reduced to an acceptable level with the help of tuners. Details of the error study and the higher order mode study along with mode stabilization technique are also described in the paper.

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Field stabilization studies for a radio frequency quadrupole accelerator

Cited by 4 publications

References 11 publications

Design and study of a continuous wave RFQ for the BISOL high intensity deuteron driver linac

Design and study of a continuous wave RFQ for the BISOL high intensity deuteron driver linac

Novel deuteron RFQ design with trapezoidal electrodes and double dipole four-vane structure

Beam dynamics and electromagnetic studies of a 3 MeV, 325 MHz radio frequency quadrupole accelerator

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