The nitrogen doping/infusion of 650 MHz cavities for the circular electron positron collider(CEPC)is investigated in this study.Two 650 MHz 1-cell cavities are first treated via buffered chemical polishing(BCP),follow...The nitrogen doping/infusion of 650 MHz cavities for the circular electron positron collider(CEPC)is investigated in this study.Two 650 MHz 1-cell cavities are first treated via buffered chemical polishing(BCP),followed by nitrogen doping.A"2/6"condition is adopted,similar to that for 1.3 GHz cavities of Linear Coherent Light Source II.The quality factor of both cavities improved to 7×10^(10)in low fields,i.e.,higher than that obtained from the baseline test.One 650 MHz two-cell cavity is nitrogen infused at 165℃for 48 h with a BCP surface base.The intrinsic quality factor(Q0)reached6×10^(10)at 22 MV/m in the vertical test,and the maximum gradient is 25 MV/m,which exceeds the specification of the CEPC(4×10^(10)at 22 MV/m).展开更多
The ECT （eddy current test） system is in use for Nb surface quality control in many laboratories. This system can inspect Nb surthce quickly using high resolution probe. The ECT system for RAON＇s cavity was made wi...The ECT （eddy current test） system is in use for Nb surface quality control in many laboratories. This system can inspect Nb surthce quickly using high resolution probe. The ECT system for RAON＇s cavity was made with these features： it has a 3-axis acting probe movenlent system, it can inspect a big size of Nb sheet, which is 1,200 mm × 365 mm and it contains the analysis program that can show the result as a 2D and 3D images as well as the relative figure of the surface level. The standard sample was made with various sizes of defects using the same Nb sheet that was used to make RISP （Rare Isotope Science Project） cavity. The ECT system conditioning was carried out to optimize the ECT operation on the frequency of which the range is from 300 KHZ to 2 MHz. The result of 900 KHZ showed the strongest signal. The conditioning experiment on other parameter will be carried out in the near future.展开更多
基金supported by the National Key Program for S&T Research and Development(No.2016YFA0400400)the Platform of Advanced Photon Source Technology R&D,National Natural Science Foundation of China(No.11505197).
文摘The nitrogen doping/infusion of 650 MHz cavities for the circular electron positron collider(CEPC)is investigated in this study.Two 650 MHz 1-cell cavities are first treated via buffered chemical polishing(BCP),followed by nitrogen doping.A"2/6"condition is adopted,similar to that for 1.3 GHz cavities of Linear Coherent Light Source II.The quality factor of both cavities improved to 7×10^(10)in low fields,i.e.,higher than that obtained from the baseline test.One 650 MHz two-cell cavity is nitrogen infused at 165℃for 48 h with a BCP surface base.The intrinsic quality factor(Q0)reached6×10^(10)at 22 MV/m in the vertical test,and the maximum gradient is 25 MV/m,which exceeds the specification of the CEPC(4×10^(10)at 22 MV/m).
文摘The ECT （eddy current test） system is in use for Nb surface quality control in many laboratories. This system can inspect Nb surthce quickly using high resolution probe. The ECT system for RAON＇s cavity was made with these features： it has a 3-axis acting probe movenlent system, it can inspect a big size of Nb sheet, which is 1,200 mm × 365 mm and it contains the analysis program that can show the result as a 2D and 3D images as well as the relative figure of the surface level. The standard sample was made with various sizes of defects using the same Nb sheet that was used to make RISP （Rare Isotope Science Project） cavity. The ECT system conditioning was carried out to optimize the ECT operation on the frequency of which the range is from 300 KHZ to 2 MHz. The result of 900 KHZ showed the strongest signal. The conditioning experiment on other parameter will be carried out in the near future.
