Accurate atomic mass data hold significant application value in various research fields,in which Penning trap mass spectrometry is considered the most precise experimental method.A cryogenic detection system is a key ...Accurate atomic mass data hold significant application value in various research fields,in which Penning trap mass spectrometry is considered the most precise experimental method.A cryogenic detection system is a key component for reading out the image charge of charged particles in Penning traps using the Fourier transform ion cyclotron resonance technique.In this paper,we present the development and characteristics of this detection system,which includes a superconducting resonator and cryogenic low-noise amplifiers.The resonator consists of delicately woven thin NbTi wires configured into a multilayer helical coil,offering a quality factor of 98004 at around 1 MHz.Low-noise amplifiers are developed based on GaAs field effect transistors,exhibiting amplification factors greater than 27 dB with a power consumption of approximately 6 mW in the frequency range of 0.1 to 10 MHz.The lowest input voltage noise is 0.8√Hz at 1 MHz.The fabrication process,operation,and measurements are elucidated in detail.展开更多
Parameters of hydrogen plasma in a miniature Penning discharge ion source, including the electron temperature and the electron density, were measured by using double probes. The results indicate that the electron dens...Parameters of hydrogen plasma in a miniature Penning discharge ion source, including the electron temperature and the electron density, were measured by using double probes. The results indicate that the electron density increases and the electron temperature decreases with the increase in gas pressure and the discharge current. The electron temperature is about 5 - 9 eV and the electron density is 6.0× 10^13 ～ 1.2 × 10^14 m^-3 while the discharge current is in a range of 50 - 120 μA.展开更多
Although the deuterium and helium have almost the same mass,a Penning Optical Gas Analyzer（POGA） system on the basis of the spectroscopic method and Penning discharging has been designed on EAST,since 2014.The POGA ...Although the deuterium and helium have almost the same mass,a Penning Optical Gas Analyzer（POGA） system on the basis of the spectroscopic method and Penning discharging has been designed on EAST,since 2014.The POGA system was developed successfully in 2015,it was the first time that EAST could detect helium partial pressure in deuterium plasma（wall conditioning and plasma operation scenario）.With dedicated calibration and proper adjustment of the parameters,the minimum concentration of helium in deuterium gas can be measured as about 0.5% instead of 1% on the other tokamak devices.Moreover,the He and D2 partial pressures are measured simultaneously.At present,the measurable range of deuterium partial pressure is 1×10^-7 mbar to 1×10^-5mbar,meanwhile the range of helium is 1×10^-8 mbar to 1×10^-5 mbar.The measurable range can be modified by means of the adjustment of POGA system＇s parameters.It is possible to detect the interesting part of the gas with a time resolution of less than 5 ms（the 200 ms because of conductance of transfer pipe at present）.The POGA system was routinely employed to wall conditioning and helium enrichment investigation in2015.Last but not the least,the low temperature plasma of POGA is generated by normal penning gauge Pfeiffer IKR gauge instead of Alcatel CF2 P,which has been suspended for a few years and was used for almost all the POGA systems in the world.展开更多
In this paper, design and construction of a modified cold molybdenum cathode Penning ion source was described. It consists of copper cylindrical anode with two cone ends and two movable cold molybdenum cathodes. The t...In this paper, design and construction of a modified cold molybdenum cathode Penning ion source was described. It consists of copper cylindrical anode with two cone ends and two movable cold molybdenum cathodes. The two cathodes were placed symmetrically at two ends of the anode. The modifications were decrease the length of the cylindrical anode to 4 cm instead of 6 cm, transform the copper emission electrode shape from plate of 40 mm length, 25 mm width and 2 mm thickness to disc of 20 mm diameter and 2 mm thickness and transform the inner uncovered area of the emission electrode from slit of 30 mm length and 10 mm width to disc of 5 mm diameter. The copper emission electrode was placed in the middle of the cylindrical anode and has aperture in the center of different diameters. Faraday cup was placed at different distances from the emission electrode aperture. The electrical discharge and the output ion beam characteristics of the modified ion source were measured at different pressures using argon gas. It was found that the optimum operating conditions of the modified ion source are; anode-cathode distance equal to 6 mm, emission electrode aperture diameter equal to 2.5 mm and emission electrode aperture, Faraday cup distance equals 3 cm. The effect of axial samarium cobalt permanent magnet of intensity equal to 300 Gauss on the discharge characteristics of the ion source was determined.展开更多
LPT （Lanzhou Penning Trap） is an ion-trap facility in Lanzhou, China. As ions can be cooled to an extremely small phase space and can be stored for a very long time, ion traps are a perfect instrument for high preci...LPT （Lanzhou Penning Trap） is an ion-trap facility in Lanzhou, China. As ions can be cooled to an extremely small phase space and can be stored for a very long time, ion traps are a perfect instrument for high precision mass measurements. A system with specialized electronics for LPT is under construction now. This system could be used for voltage and timing control to make ions moving in a special mode, and the data acquisition and analysis online/offline could be achieved in the mean time. The requirements of control system, the distribution of hardware, the overview of software, and the latest progress of LPTCtrlSys （Lanzhou Penning Trap Control System） are presented.展开更多
Based on the essential theory of Penning gases, the discharge characteristics of He-Ar Penning gases in insulating tubes were analyzed qualitatively. The relation between the effective length of an antenna column fill...Based on the essential theory of Penning gases, the discharge characteristics of He-Ar Penning gases in insulating tubes were analyzed qualitatively. The relation between the effective length of an antenna column filled with He-Ar Penning gases and the applied radio frequency （RF） power was investigated both theoretically and experimentally. The distribution of the plasma density along the antenna column in different conditions was studied. The receiving characteristics of local frequency modulated （FM） electromagnetic waves by the plasma antenna filled with He-Ar Penning gases were compared with those by an aluminum antenna with the same dimensions. Results show that it is feasible to take plasma antennas filled with He-Ar Penning gases as receiving antennas.展开更多
基金supported by the National Key R&D Program of China(No.2023YFA1606501)the National Natural Science Foundation of China(Nos.12204110 and 12474251)+2 种基金Shanghai Pujiang Program(No.22PJ1401100)Max-Planck Partner Group Projectthe Fudan University Yan Liyuan-EnSiKai Foundation(JX240003)。
文摘Accurate atomic mass data hold significant application value in various research fields,in which Penning trap mass spectrometry is considered the most precise experimental method.A cryogenic detection system is a key component for reading out the image charge of charged particles in Penning traps using the Fourier transform ion cyclotron resonance technique.In this paper,we present the development and characteristics of this detection system,which includes a superconducting resonator and cryogenic low-noise amplifiers.The resonator consists of delicately woven thin NbTi wires configured into a multilayer helical coil,offering a quality factor of 98004 at around 1 MHz.Low-noise amplifiers are developed based on GaAs field effect transistors,exhibiting amplification factors greater than 27 dB with a power consumption of approximately 6 mW in the frequency range of 0.1 to 10 MHz.The lowest input voltage noise is 0.8√Hz at 1 MHz.The fabrication process,operation,and measurements are elucidated in detail.
文摘Parameters of hydrogen plasma in a miniature Penning discharge ion source, including the electron temperature and the electron density, were measured by using double probes. The results indicate that the electron density increases and the electron temperature decreases with the increase in gas pressure and the discharge current. The electron temperature is about 5 - 9 eV and the electron density is 6.0× 10^13 ～ 1.2 × 10^14 m^-3 while the discharge current is in a range of 50 - 120 μA.
基金funded by National Magnetic Confinement Fusion Science Program of China under Contract No.2013GB114004,No.2014GB106005 & No.2015GB101000National Nature Science Foundation of China under Contract No.11625524,No.11321092 and No.11405210partly supported by the Japan Society for the Promotion of ScienceNational Research Foundation of Korea-National Science Foundation of China(JSPS-NRF-NSFC) A3 Foresight Program in the field of Plasma Physics(NSFC No.11261140328)
文摘Although the deuterium and helium have almost the same mass,a Penning Optical Gas Analyzer（POGA） system on the basis of the spectroscopic method and Penning discharging has been designed on EAST,since 2014.The POGA system was developed successfully in 2015,it was the first time that EAST could detect helium partial pressure in deuterium plasma（wall conditioning and plasma operation scenario）.With dedicated calibration and proper adjustment of the parameters,the minimum concentration of helium in deuterium gas can be measured as about 0.5% instead of 1% on the other tokamak devices.Moreover,the He and D2 partial pressures are measured simultaneously.At present,the measurable range of deuterium partial pressure is 1×10^-7 mbar to 1×10^-5mbar,meanwhile the range of helium is 1×10^-8 mbar to 1×10^-5 mbar.The measurable range can be modified by means of the adjustment of POGA system＇s parameters.It is possible to detect the interesting part of the gas with a time resolution of less than 5 ms（the 200 ms because of conductance of transfer pipe at present）.The POGA system was routinely employed to wall conditioning and helium enrichment investigation in2015.Last but not the least,the low temperature plasma of POGA is generated by normal penning gauge Pfeiffer IKR gauge instead of Alcatel CF2 P,which has been suspended for a few years and was used for almost all the POGA systems in the world.
文摘In this paper, design and construction of a modified cold molybdenum cathode Penning ion source was described. It consists of copper cylindrical anode with two cone ends and two movable cold molybdenum cathodes. The two cathodes were placed symmetrically at two ends of the anode. The modifications were decrease the length of the cylindrical anode to 4 cm instead of 6 cm, transform the copper emission electrode shape from plate of 40 mm length, 25 mm width and 2 mm thickness to disc of 20 mm diameter and 2 mm thickness and transform the inner uncovered area of the emission electrode from slit of 30 mm length and 10 mm width to disc of 5 mm diameter. The copper emission electrode was placed in the middle of the cylindrical anode and has aperture in the center of different diameters. Faraday cup was placed at different distances from the emission electrode aperture. The electrical discharge and the output ion beam characteristics of the modified ion source were measured at different pressures using argon gas. It was found that the optimum operating conditions of the modified ion source are; anode-cathode distance equal to 6 mm, emission electrode aperture diameter equal to 2.5 mm and emission electrode aperture, Faraday cup distance equals 3 cm. The effect of axial samarium cobalt permanent magnet of intensity equal to 300 Gauss on the discharge characteristics of the ion source was determined.
基金supported by National Natural Science Foundation of China (Nos. 10627504, 11075188, 10925526)the Chinese Academy of Sciences(No. KJCX2-YW-N44), the Ministry of Science and Technology of China (No. 2007CB815000)
文摘LPT （Lanzhou Penning Trap） is an ion-trap facility in Lanzhou, China. As ions can be cooled to an extremely small phase space and can be stored for a very long time, ion traps are a perfect instrument for high precision mass measurements. A system with specialized electronics for LPT is under construction now. This system could be used for voltage and timing control to make ions moving in a special mode, and the data acquisition and analysis online/offline could be achieved in the mean time. The requirements of control system, the distribution of hardware, the overview of software, and the latest progress of LPTCtrlSys （Lanzhou Penning Trap Control System） are presented.
文摘Based on the essential theory of Penning gases, the discharge characteristics of He-Ar Penning gases in insulating tubes were analyzed qualitatively. The relation between the effective length of an antenna column filled with He-Ar Penning gases and the applied radio frequency （RF） power was investigated both theoretically and experimentally. The distribution of the plasma density along the antenna column in different conditions was studied. The receiving characteristics of local frequency modulated （FM） electromagnetic waves by the plasma antenna filled with He-Ar Penning gases were compared with those by an aluminum antenna with the same dimensions. Results show that it is feasible to take plasma antennas filled with He-Ar Penning gases as receiving antennas.
