Implantation experiments of low energy（1 keV【E【18 keV）hydrogen ion beamson hydrogen loaded metals are performed with high beam density(J<sub>max</sub>1.2 mA/cm<sup>2</sup>)and lowbeam densi...Implantation experiments of low energy（1 keV【E【18 keV）hydrogen ion beamson hydrogen loaded metals are performed with high beam density(J<sub>max</sub>1.2 mA/cm<sup>2</sup>)and lowbeam density(J<sub>min</sub>0.02 mA/cm<sup>2</sup>).Palladium and titanium foils（plates）are bombarded withproton and deuteron beams in order to compare the atomic and nuclear interactions between dif-ferent ion beams.X-ray and charged particles are measured,and neutron and gamma doses arealso monitored during the implantation experiments.An anomalous peak in X-spectra,whoseenergy is about four times the beam energy,is observed during the high beam density experi-ment.The peak moves from about 40 keV to 62 keV and FWHM reduces rapidly,while thebeam energy and intensity increase.Another wide peak with over twice the beam energy is mea-sured in experiment with low beam density.It is located between 16 keV and 30 keV,and itspeak energy increases with the increase of implantation dose（implantation time）.Some anoma-lous intensities of neutrons correlated with a charged particle peak（2.93,3.85 MeV）are alsoobserved in the deuteron-palladium experiment.The highest neutron intensity reaches about8×10<sup>4</sup> n/s,while the beam energy and intensity are about 15 keV and 1.0 mA,respectively.展开更多
he present paper focuses on the modifying effects of ion beam mixing, ion im-planting and ion sputtering on hydrogen evolution electrodes. It was discovered thatthe four types of electrodes possessed excellent catalyt...he present paper focuses on the modifying effects of ion beam mixing, ion im-planting and ion sputtering on hydrogen evolution electrodes. It was discovered thatthe four types of electrodes possessed excellent catalytic activity in acid or alkalinemedia and potential stability in long term electrolysis of water under high currentdensity. Their stability and applying life-span greatly surpass those of other elec-trodes activated by electrodepositing and other method. The effects of temperatureand roughness on function of electrodes were also examined. XPS and AES wereapplied to analyse the surface composition and bond states of the electrodes, andthe distribution of concentration varying with depth, and to explain the law of theexperiments .展开更多
We consider two possible schemes for generation and detection of a monoenergetic directed beam of neutrinos which may have application to neutrino communication. First, we consider generation of a directed neutrino be...We consider two possible schemes for generation and detection of a monoenergetic directed beam of neutrinos which may have application to neutrino communication. First, we consider generation of a directed neutrino beam using electron capture beta decay in hydrogen-like ions. Next, we suggest detection of a directed neutrino beam using resonant absorption of a neutrino by a bare nucleus with the generation of a bound electron. This reaction is inverse to electron capture beta decay, and we call it “Bound State Inverse Beta Decay (BSIBD)”. We show that the recoil effect can be eliminated by an appropriate choice of velocities for the ions and bare nuclei. Finally, we consider a combination of a solid state source of a directed mono-energetic neutrino beam and its detection using BSIBD.展开更多
A practical 2.45-GHz microwave-driven Cs-free H^- source was improved based on the experimental H^- source at Peking University（PKU）. Several structural improvements were implemented to meet the practical requiremen...A practical 2.45-GHz microwave-driven Cs-free H^- source was improved based on the experimental H^- source at Peking University（PKU）. Several structural improvements were implemented to meet the practical requirements of Xi＇an Proton Application Facility（XiPaf）. Firstly, the plasma chamber size was optimized to enhance the plasma intensity and stability. Secondly, the filter magnetic field and electron deflecting magnetic field were enhanced to reduce co-extracted electrons. Thirdly, a new two-electrode extraction system with farther electrode gap and enhanced water cooling ability to diminish spark and sputter during beam extraction was applied. At last, the direct H^- current measuring method was adopted by the arrangement of a new pair of bending magnets before Faraday cup（FC） to remove residual electrons. With these improvements, electron cyclotron resonance（ECR） magnetic field optimization experiments and operation parameter variation experiments were carried out on the H^- ion source and a maximum 8.5-mA pure H^- beam was extracted at 50 kV with the time structure of 100 Hz/0.3 ms. The root-mean-square（RMS） emittance of the beam is 0.25 Π·mm·mrad. This improved H^- source and extraction system were maintenance-free for more than 200 hours in operation.展开更多
A miniaturized 2.45 GHz permanent magnet electron cyclotron resonance（PMECR） ion source, which has the ability of producing a tens-m A H＋beam, has been built and tested at Peking University（PKU）. Its plasma chamb...A miniaturized 2.45 GHz permanent magnet electron cyclotron resonance（PMECR） ion source, which has the ability of producing a tens-m A H＋beam, has been built and tested at Peking University（PKU）. Its plasma chamber dimension is Φ30 mm×40 mm and the whole size of the ion source is Φ180 mm×130 mm. This source has a unique structure with the whole source body embedded into the extraction system. It can be operated in both continuous wave（CW） mode and pulse mode. In the CW mode, more than 20 m A hydrogen ion beam at 40 k V can be obtained with the microwave power of 180 W and about 1 m A hydrogen ion beam is produced with a microwave power of 10 W. In the pulse mode, more than50 m A hydrogen ion beam with a duty factor of 10% can be extracted when the peak microwave power is 1800 W.展开更多
利用氢离子束辅助磁控溅射制备氢化非晶硅薄膜(a-Si∶H),借助拉曼光谱仪、红外光谱仪和椭圆偏振光谱仪等分析测试手段,研究衬底温度对a-Si∶H薄膜结构特性影响规律。结果表明在合适的衬底温度下氢离子束辅助磁控溅射制备的a-Si∶H薄膜...利用氢离子束辅助磁控溅射制备氢化非晶硅薄膜(a-Si∶H),借助拉曼光谱仪、红外光谱仪和椭圆偏振光谱仪等分析测试手段,研究衬底温度对a-Si∶H薄膜结构特性影响规律。结果表明在合适的衬底温度下氢离子束辅助磁控溅射制备的a-Si∶H薄膜具有较好短程有序度和中程有序度;当衬底温度为200℃时,薄膜的结构特性最优,a-Si∶H薄膜的次带吸收系数为0.46 cm^(-1)、氢含量为10.36%(原子比)、微结构因子为0.68和光学带隙为1.94 e V。展开更多
文摘Implantation experiments of low energy（1 keV【E【18 keV）hydrogen ion beamson hydrogen loaded metals are performed with high beam density(J<sub>max</sub>1.2 mA/cm<sup>2</sup>)and lowbeam density(J<sub>min</sub>0.02 mA/cm<sup>2</sup>).Palladium and titanium foils（plates）are bombarded withproton and deuteron beams in order to compare the atomic and nuclear interactions between dif-ferent ion beams.X-ray and charged particles are measured,and neutron and gamma doses arealso monitored during the implantation experiments.An anomalous peak in X-spectra,whoseenergy is about four times the beam energy,is observed during the high beam density experi-ment.The peak moves from about 40 keV to 62 keV and FWHM reduces rapidly,while thebeam energy and intensity increase.Another wide peak with over twice the beam energy is mea-sured in experiment with low beam density.It is located between 16 keV and 30 keV,and itspeak energy increases with the increase of implantation dose（implantation time）.Some anoma-lous intensities of neutrons correlated with a charged particle peak（2.93,3.85 MeV）are alsoobserved in the deuteron-palladium experiment.The highest neutron intensity reaches about8×10<sup>4</sup> n/s,while the beam energy and intensity are about 15 keV and 1.0 mA,respectively.
文摘he present paper focuses on the modifying effects of ion beam mixing, ion im-planting and ion sputtering on hydrogen evolution electrodes. It was discovered thatthe four types of electrodes possessed excellent catalytic activity in acid or alkalinemedia and potential stability in long term electrolysis of water under high currentdensity. Their stability and applying life-span greatly surpass those of other elec-trodes activated by electrodepositing and other method. The effects of temperatureand roughness on function of electrodes were also examined. XPS and AES wereapplied to analyse the surface composition and bond states of the electrodes, andthe distribution of concentration varying with depth, and to explain the law of theexperiments .
文摘We consider two possible schemes for generation and detection of a monoenergetic directed beam of neutrinos which may have application to neutrino communication. First, we consider generation of a directed neutrino beam using electron capture beta decay in hydrogen-like ions. Next, we suggest detection of a directed neutrino beam using resonant absorption of a neutrino by a bare nucleus with the generation of a bound electron. This reaction is inverse to electron capture beta decay, and we call it “Bound State Inverse Beta Decay (BSIBD)”. We show that the recoil effect can be eliminated by an appropriate choice of velocities for the ions and bare nuclei. Finally, we consider a combination of a solid state source of a directed mono-energetic neutrino beam and its detection using BSIBD.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11775007 and 11575013)
文摘A practical 2.45-GHz microwave-driven Cs-free H^- source was improved based on the experimental H^- source at Peking University（PKU）. Several structural improvements were implemented to meet the practical requirements of Xi＇an Proton Application Facility（XiPaf）. Firstly, the plasma chamber size was optimized to enhance the plasma intensity and stability. Secondly, the filter magnetic field and electron deflecting magnetic field were enhanced to reduce co-extracted electrons. Thirdly, a new two-electrode extraction system with farther electrode gap and enhanced water cooling ability to diminish spark and sputter during beam extraction was applied. At last, the direct H^- current measuring method was adopted by the arrangement of a new pair of bending magnets before Faraday cup（FC） to remove residual electrons. With these improvements, electron cyclotron resonance（ECR） magnetic field optimization experiments and operation parameter variation experiments were carried out on the H^- ion source and a maximum 8.5-mA pure H^- beam was extracted at 50 kV with the time structure of 100 Hz/0.3 ms. The root-mean-square（RMS） emittance of the beam is 0.25 Π·mm·mrad. This improved H^- source and extraction system were maintenance-free for more than 200 hours in operation.
基金Project supported by the National Basic Research Program of China(Grant No.2014CB845502)the National Natural Science Foundation of China(Grant No.11575013)
文摘A miniaturized 2.45 GHz permanent magnet electron cyclotron resonance（PMECR） ion source, which has the ability of producing a tens-m A H＋beam, has been built and tested at Peking University（PKU）. Its plasma chamber dimension is Φ30 mm×40 mm and the whole size of the ion source is Φ180 mm×130 mm. This source has a unique structure with the whole source body embedded into the extraction system. It can be operated in both continuous wave（CW） mode and pulse mode. In the CW mode, more than 20 m A hydrogen ion beam at 40 k V can be obtained with the microwave power of 180 W and about 1 m A hydrogen ion beam is produced with a microwave power of 10 W. In the pulse mode, more than50 m A hydrogen ion beam with a duty factor of 10% can be extracted when the peak microwave power is 1800 W.
文摘利用氢离子束辅助磁控溅射制备氢化非晶硅薄膜(a-Si∶H),借助拉曼光谱仪、红外光谱仪和椭圆偏振光谱仪等分析测试手段,研究衬底温度对a-Si∶H薄膜结构特性影响规律。结果表明在合适的衬底温度下氢离子束辅助磁控溅射制备的a-Si∶H薄膜具有较好短程有序度和中程有序度;当衬底温度为200℃时,薄膜的结构特性最优,a-Si∶H薄膜的次带吸收系数为0.46 cm^(-1)、氢含量为10.36%(原子比)、微结构因子为0.68和光学带隙为1.94 e V。
