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

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We developed a novel compact structure, called a Coupled RFQ-SFRFQ (CRS), to accelerate a 0.8 MeV helium beam for a materials irradiation project. A high accelerating efficiency was achieved by replacing the accelerating section of the radio frequency quadrupole (RFQ) with a separated-function radio frequency quadrupole (SFRFQ) structure, in a single cavity. Following the electromagnetic simulations, RF measurement of the CRS cavity was performed, including low RF power and high RF power measurement. Recently, beam experiments on the CRS linac indicated that the maximum accelerated beam current could reach 2 mA with an energy of 0.8 MeV and energy spread (FWHM) of 3.1%. The experimental measurement results showed good consistency with the beam dynamics simulations.

Section: Discussionmentioning

confidence: 99%

Beam commissioning of the coupled RFQ-SFRFQ cavity

Wang¹,

Xia²,

Lu³

et al. 2021

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“…The inter-vane voltage tilt (figure 3 a) and the inter-vane voltage harmonic [10] (figure 3 b) are used to replace the unevenness field. They are implemented in TOUTATIS [11].…”

Section: Beam Dynamics and Error Studymentioning

confidence: 99%

“…There are two common methods to avoid the adjacent dipole mode mixing together, 𝜋-mode stabilizing loops (PISLs) and DSRs [13]. More than 10 MHz mode separation can be achieved with the PISLs [10], but its structure is more complicated. The DSRs decreases the costs of design and The choice of the position of the DSRs is determined by the necessity of have a slight perturbation on the quadrupole frequency [15].…”

Section: Dsrs Design and Mode Separationmentioning

confidence: 99%

RF design and tuning of a deuteron RFQ for detecting impurity deposition on a tokamak

Liu¹,

Bai²,

Wei³

et al. 2022

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Peking University and Southwestern Institute of Physics are jointly developing a new deuteron Radio Frequency Quadrupole (RFQ) accelerator to study the migration and deposition of impurities on the first wall of a tokamak facility. The RFQ operates at 162.5 MHz with the duty factor of 1%, which can accelerate 10 mA deuteron beam from 40 keV up to 1.5 MeV within 2.2 m length. Such four-vane RFQ is divided into two segments and equipped with 40 tuners in total. In the electromagnetic (EM) design, the dipole stabilizer rods (DSRs) were optimized to obtain a mode separation of 3.1 MHz. The tuners and undercuts were also designed and optimized to fulfill the requirements of the resonant frequency, flat longitudinal field distribution and field tuning. Following the EM design, multi-physics analysis and structure error analysis was carried out. The cavity was fabricated with 99.9% oxygen-free electronic (OFE) copper. The assembly and braze of each RFQ module have been completed, the results of metrological measurements via coordinate measuring machine (CMM) indicate that there was no unexpected deformation. The intrinsic Q-value of the whole cavity is 12834 in the low level radio frequency (RF) measurements, which is 87% of the theoretical simulation with electrical conductivity of 5.8 × 107 S/m. After tuning, the quadrupole perturbative component decreased from 2.6% to 0.6%, and the dipole perturbative components decreased from 6.1% to 1%.

“…This can simplify the difficulty of beam dynamics, RF electromagnetic design, and field tuning. To increase the acceleration gradient or achieve an equipartitioning scheme, some RFQs, such as CPHS [10,11], BISOL [12], J-PARC [13], IFMIF [14],…”

Section: Introductionmentioning

confidence: 99%

Field tuning study and RF electromagnetic design of a continuous-wave RFQ with ramped inter-vane voltage for AB-BNCT

Li,

Chen,

et al. 2024

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A compact radio frequency quadrupole (RFQ) linac for accelerator-based boron neutron capture therapy is being developed at Xi'an Jiaotong University. By adopting a ramped inter-vane voltage in the beam dynamics design, the RFQ could accelerate a continuous wave proton beam to 2.6 MeV over a length of 4 m, effectively decreasing costs and saving space. To meet the beam-dynamics requirements, both the vane width and undercut were optimized during the electromagnetic design. In addition, π-mode stabilization loops were included to increase the mode separation, and fixed tuners with varying diameters were installed to obtain close frequency-tuning sensitivity. It was established that the field unflatness can be controlled within ±1.5% when all tuners remain at their nominal insertion depth. Optimized cooling-channel design was completed, and multi-physics analysis was conducted. The water tuning coefficients of the vane and wall channels were analyzed to establish the ability to fine tune the RFQ during operation.