The effect of nitrogen infusion on a 162.5 MHz low beta superconducting HWR cavity

Zhu, Feng; Hao, Jiankui; Quan, Shengwen; Wang, F.; Chen, S.; Chen, M.; Feng, Liwen; Cheng, Anqi; Liu, K.X.

doi:10.1016/j.nima.2019.04.087

Cited by 5 publications

(4 citation statements)

References 4 publications

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“…This damaged surface needs to be removed after the cavity processing. The standard procedure involves ultrasonic cleaning, buffering chemical polishing (BCP) of 150 µm, hydrogen removal baking, additional BCP of 30 µm, high-pressure water rinsing (HPR), ultra-clean-room assembly, and low-temperature baking [40,41]. Among them, BCP can affect the frequency of the cavity.…”

Section: Post-treatment Processesmentioning

confidence: 99%

“…During the stamping and machining phases, the surface of the 3 mm high-purity ni obium plate used for cavity fabrication may be damaged, and the typical damaged laye is 100 to 200 μm. This damaged surface needs to be removed after the cavity processing The standard procedure involves ultrasonic cleaning, buffering chemical polishing (BCP of 150 μm, hydrogen removal baking, additional BCP of 30 μm, high-pressure water rins ing (HPR), ultra-clean-room assembly, and low-temperature baking [40,41]. Among them BCP can affect the frequency of the cavity.…”

Section: Post-treatment Processesmentioning

confidence: 99%

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Design of a 162.5 MHz Superconducting Radio-Frequency Quadrupole for High-Intensity Proton Acceleration

Xia,

Wang,

et al. 2023

Applied Sciences

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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.

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Section: Post-treatment Processesmentioning

confidence: 99%

Section: Post-treatment Processesmentioning

confidence: 99%

Design of a 162.5 MHz Superconducting Radio-Frequency Quadrupole for High-Intensity Proton Acceleration

Xia,

Wang,

et al. 2023

Applied Sciences

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“…5 MV/m. Finally, it was recently [11][12][13][14] demonstrated that nitrogen doping (N-Doping) and infusion (N-infusion) allows reduction of RF losses in SRF cavities by a factor ~3. However, when SRF resonators are subjected to N-doping, a systematic reduction of max acc E of was observed in different laboratories [11][12][13].…”

Section: Figure 1 1 Impact Of Cavity Fabrication and Preparation Proc...mentioning

confidence: 99%

Thermal conductivity of niobium and thermally sprayed copper at cryogenic temperature

Fouaidy

2022

IOP Conf. Ser.: Mater. Sci. Eng.

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We have developed a test facility dedicated to thermal conductivity k(T) measurements at low temperature. These experimental devices allow the test of four samples simultaneously during each run. The measurements are performed using steady-state axial heat flow method with a careful control of heat leaks to the surrounding. The apparatus was successfully used for measuring k(T) (Temperature T in the range: 1.5 K - 10 K) of niobium and other materials used for the fabrication of Superconducting Radio Frequency (SRF) cavities. We have tested the following samples: 1) niobium samples from different supplier (as received or/and after various high temperature Heat Treatments (HT)), 2) thermally sprayed copper coatings. The resulting experimental data are presented and compared to the experimental results previously reported by other groups and theoretical values. As expected heat treatment have a strong impact on k(T) and in particular on the phonons peak at T∼2K. More precisely, HT @ 1200°C with Ti gettering improves the Nb Residual Resistance Ratio (RRR) by a factor of 3 and consequently k(T). Finally, the correlation between the niobium RRR and the thermal conductivity. at T=4.2 K is confirmed in good agreement with the Wiedemann-Franz law

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“…The RF measurements and vertical test results showed it had good mechanical properties and high gradient. The maximum gradient of the cavity reached 14.5 MV/m at 4.2 K and 17 MV/m at 2 K; field emission started at 14 MV/m, as shown in figure 12 [27]. In order to meet the extremely high stability and reliability requirements of the facility in long-term stable cw operation mode, over-design and redundancy strategies are implemented in the dynamics design of the SRF linac.…”

Section: Srf Linac Beam Dynamics Design 41 Development Of the Hwr Cavitymentioning

confidence: 99%

Beam dynamics design and error study of BISOL deuteron driver linac

Wang

et al. 2020

J. Inst.

Self Cite

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The high intensity deuteron linac, one of the drivers of BISOL, aims to accelerate a continuous wave (cw) deuteron beam up to 40 MeV with a beam current of 20 mA, which can also be operated independently as the Multi-Aimed Intense Neutron Source (MAINS). As the high beam power and beam current, high reliability and strict beam loss are demand for the deuteron driver linac. The beam dynamics design of the driver linac, including the radio frequency quadrupole (RFQ), medium energy beam transport line (MEBT) and superconducting rf (SRF) linac, has been designed and optimized to meet the required requirements. In order to prevent halo formation and achieve strict beam losses, beam halo matching is implemented in our design. The simulation results predict a transmission efficiency of above 99% and the beam power losses meet requirements of less than l W/m in the SRF linac. Detailed error studies are performed to evaluate the sensitivity of the bean dynamics design at last. The general design considerations and the overall beam dynamics of the driver linac are presented in this paper.

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The effect of nitrogen infusion on a 162.5 MHz low beta superconducting HWR cavity

Cited by 5 publications

References 4 publications

Design of a 162.5 MHz Superconducting Radio-Frequency Quadrupole for High-Intensity Proton Acceleration

Design of a 162.5 MHz Superconducting Radio-Frequency Quadrupole for High-Intensity Proton Acceleration

Thermal conductivity of niobium and thermally sprayed copper at cryogenic temperature

Beam dynamics design and error study of BISOL deuteron driver linac

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