Based on the latest design requirements proposed by the Beijing On-Line Isotope Separation (BISOL) project, a new ${\mathrm{Sn}}^{22+}$-based, 81.25 MHz CW radio frequency quadrupole (RFQ) with external bunching has been designed. This RFQ can accelerate ${\mathrm{Sn}}^{22+}$ to 0.5 MeV/u with an output longitudinal-normalized rms emittance of 0.20 keV/u·ns over a length of 5.6 m. The tolerance and error analysis results indicate that this RFQ can handle a wide range of non-ideal beams while maintaining relatively lower longitudinal emittance growth and higher transmission efficiency. To maintain the beam intensity, the RFQ will simultaneously accelerate three kinds of high-charge-state mixed ions (${}^{132}{\mathrm{Sn}}^{21+}$, ${}^{132}{\mathrm{Sn}}^{22+}$ and ${}^{132}{\mathrm{Sn}}^{23+}$), the simulation results given by Impact-T show that the RFQ can achieve high transmission of the mixed beam. Compared with the previous ${\mathrm{Sn}}^{21+}$-based internal bunching RFQ scheme, this RFQ has a shorter length and smaller output emittance, which is beneficial to the designs of subsequent Medium-energy Beam Transport (MEBT) and Drift Tube Linac (DTL). In electromagnetic design, a four-vane structure with 48 tuners and 16 $\pi$-mode stabilizers (PSLs) were chosen. The results of the multi-physics analysis show that the maximum temperature rise and the maximum deformation of the cavity are 13.6 K and 40.3 µm, respectively. The results simulated with CST Microwave Studio (CST) and HFSS software were consistent.

In order to figure out the migration and deposition of impurities on the first wall of HL-2A/2M tokamak, Peking University and Southwestern Institute of Physics are co-developing a deuteron RFQ as part of the in situ ion-beam diagnostic for the material. The RFQ, which operates at 162.5 MHz, is designed to accelerate a 10-mA deuteron beam from 40 keV up to 1.5 MeV. Key design considerations and the final design parameters are presented. The RFQ has been conditioned at a 1% duty factor for 80 h at RF cavity power of 55 kW. The specific shunt impedance of the cavity is 221 kΩ·m by measuring the bremsstrahlung spectrum. The intrinsic Q-value after the high-power tests measured by the Ring-Down method is 13,780. Beam commissioning has been taken place during the first half of 2021, and the beam measurements include beam current and energy of ²H⁺ ion. A 10 mA ²H⁺ beam was successfully accelerated through the RFQ.

This paper presents the design of a high-intensity 10 mA deuteron RFQ accelerator that generates a 2.1 MeV beam in a continuous wave (CW) mode. The operation frequency is 162.5 MHz. The results of beam dynamics simulations demonstrate excellent output beam quality, achieving a transmission efficiency of 98.63%. The beam tracking results indicate that the RFQ is capable of managing errors within reasonable tolerances. In addition, the RF electromagnetic design and optimization are based on an RFQ model. Multiphysics simulations are then performed for the CW mode. Vacuum calculations suggest that the RFQ requires four 1200 L/s vacuum pumps and one 440 L/s ion pump to attain a vacuum pressure of 10⁻⁶ Pa.

Understanding moisture transport is an important step in the study of the durability of cement-based materials. A neutron imaging detection method for water transport in cement-based materials, based on a compact neutron source is provided. We visualize the moisture transport and obtain the capillarity coefficients for different cement-based materials using PKUNIFTY.

Superconducting (SC) radio-frequency quadrupoles (RFQs) have exhibited outstanding performance in transmitting and accelerating high-current continuous-wave (CW) ion beams. They can complete beam acceleration at a much higher gradient and with much lower power consumption compared with normal conducting (NC) RFQs. In this study, we introduce a novel SC RFQ scheme operating at 162.5 MHz to accelerate 10 mA proton beams from 30 keV to 2.5 MeV. It will be used as a crucial component for a neutron source dedicated to Boron Neutron Capture Therapy (BNCT) and neutron imaging projects. For efficient transmission of proton beams, we selected a relatively high inter-vane voltage of 240 kV, and the beam dynamics design yielded satisfactory results. Subsequently, RF design and multi-physics analysis were carried out to validate the reliability of the design. A 30-centimeter-long cavity was specifically designed for the vertical test and allowed for a thorough evaluation of the performance of the SC RFQ after post-treatments. Additionally, the tuning design of the 30 cm cavity was also carried out.