When an energetic highly charged ion (HCI) collides with an atom, the target electrons may be captured by theprojectile ion, either radiatively or non-radiatively. During a radiative electron capture (REC), a target e...When an energetic highly charged ion (HCI) collides with an atom, the target electrons may be captured by theprojectile ion, either radiatively or non-radiatively. During a radiative electron capture (REC), a target electronis transferred to the projectile accompanying with a photon emission, which carries away the excess energy andmomentum. During a non-radiative electron capture (NRC), the energy and momentum conservations are ensuredby the target nucleus[1]. If the captured electrons are populated in excited states, photons maybe emitted duringthe following stabilization processes, and therefore the X-ray spectrum can provide information about the initialpopulation. However, if a solid target is employed, the single-collision condition cannot be ensured when consideringthe capture processes, as well as strong background will be produced[2]. With the development of heavy ioncooling storage rings, the experimental luminance is enhanced by the strong ion beams when a gaseous target isprerequisite[3].展开更多
First we calibrated the spectrometer in atmosphere using the peak-channel of 241Am, Thc-c' standard radioactive source while the window diameter isφ3. 0 mm and gained following formula with respect to the energy ...First we calibrated the spectrometer in atmosphere using the peak-channel of 241Am, Thc-c' standard radioactive source while the window diameter isφ3. 0 mm and gained following formula with respect to the energy (E/MeV) ofαand the channel (Ch): E=1. 507 55 + 0. 016 31×Ch+6. 235 24×10-6×Ch2 So, when E=5. 486 MeV, the Ch is equal to 221. 493. When changing the diameter of incident window toφ1.5 mm, we find the peak-channel of展开更多
The cross-section ratios-ofσDE/σSC,σTE/σSC,σQE/σSC andσME/σSC as well as the relative ratios among reaction channels in double-electron active, triple-electron active and quadruple-electron active are measured...The cross-section ratios-ofσDE/σSC,σTE/σSC,σQE/σSC andσME/σSC as well as the relative ratios among reaction channels in double-electron active, triple-electron active and quadruple-electron active are measured in I3C6+-Ne collision in the energy region of 4. 15-11. 08 keV/u by employing position-sensitive and timeof -flight coincident techniques. The bare isotope 13C6+ ions were provided by 14. 5 GHz ECR ion source展开更多
The cluster target system was installed to the due position last year. Several test experiments such as the test of vacuum system, the calibration of the flux and the stability of system have been done after the insta...The cluster target system was installed to the due position last year. Several test experiments such as the test of vacuum system, the calibration of the flux and the stability of system have been done after the installation and collimation of cluster internal target. However, there are two problems which hinder us from going further. One is the blocking of nozzle which results in the failure of a long-term system running; the other is the low pumping power for Hydrogen gases in the first stage of the cluster source cham-展开更多
In highly charged ions(HCI)-atom collisions, many electrons are active and much more channels are opened, and the collision dynamics therefore is much more complicated. Because of the complexity originated from many a...In highly charged ions(HCI)-atom collisions, many electrons are active and much more channels are opened, and the collision dynamics therefore is much more complicated. Because of the complexity originated from many active electrons which are involved in HCI and atoms collisions, the full quantum treatment is rather difficult, whereas the simple classical over-the-barrier models and semiempirical展开更多
Radiative electron capture(REC)and nonradiative capture(NRC)are two competing mechanisms in relativistic collisions of highly charged ions with atoms[1].REC means electron transfer from target to projectile with the e...Radiative electron capture(REC)and nonradiative capture(NRC)are two competing mechanisms in relativistic collisions of highly charged ions with atoms[1].REC means electron transfer from target to projectile with the emission of one photon for satisfying energy and momentum conservation laws.展开更多
In collisions between energetic highly charged ions and atoms,the ions could remove the electrons of the target atoms,or be excited into high-level states.In the first case,the target electrons not only be captured in...In collisions between energetic highly charged ions and atoms,the ions could remove the electrons of the target atoms,or be excited into high-level states.In the first case,the target electrons not only be captured into ground and excited states of the projectile ions,but also be ionized to free.Non-radiative capture(NRC)and radiative electron capture(REC)are two competing mechanisms in fast collisions[1].NRC means electron transfer from a bound state of the target to a bound states of the projectile without the emission of radiation;REC is produced with simultaneous the emission of photon for satisfying energy and momentum conservation laws.The physical essence is the competition between the“electron-nucleus”interaction and the“electron-vacuum”interaction.NRC is dominant in collisions of high-Z ions with heavy target atoms at moderate energies.REC entirely determine the electron capture channel for high collision velocities and light targets[1].Measuring the relative strength of the projectile x-ray emission associated with electron capture could determine state-selective population,angular distribution of single capture Ly 1 or double capture Kα1 and Kα2,would provide new detailed information on the dynamics of ion-atom collisions and atomic structure studies[1].展开更多
文摘When an energetic highly charged ion (HCI) collides with an atom, the target electrons may be captured by theprojectile ion, either radiatively or non-radiatively. During a radiative electron capture (REC), a target electronis transferred to the projectile accompanying with a photon emission, which carries away the excess energy andmomentum. During a non-radiative electron capture (NRC), the energy and momentum conservations are ensuredby the target nucleus[1]. If the captured electrons are populated in excited states, photons maybe emitted duringthe following stabilization processes, and therefore the X-ray spectrum can provide information about the initialpopulation. However, if a solid target is employed, the single-collision condition cannot be ensured when consideringthe capture processes, as well as strong background will be produced[2]. With the development of heavy ioncooling storage rings, the experimental luminance is enhanced by the strong ion beams when a gaseous target isprerequisite[3].
文摘First we calibrated the spectrometer in atmosphere using the peak-channel of 241Am, Thc-c' standard radioactive source while the window diameter isφ3. 0 mm and gained following formula with respect to the energy (E/MeV) ofαand the channel (Ch): E=1. 507 55 + 0. 016 31×Ch+6. 235 24×10-6×Ch2 So, when E=5. 486 MeV, the Ch is equal to 221. 493. When changing the diameter of incident window toφ1.5 mm, we find the peak-channel of
基金Supported by NSFC (10304019,10134010 and 10375080)
文摘The cross-section ratios-ofσDE/σSC,σTE/σSC,σQE/σSC andσME/σSC as well as the relative ratios among reaction channels in double-electron active, triple-electron active and quadruple-electron active are measured in I3C6+-Ne collision in the energy region of 4. 15-11. 08 keV/u by employing position-sensitive and timeof -flight coincident techniques. The bare isotope 13C6+ ions were provided by 14. 5 GHz ECR ion source
基金Supported by the National Natural Science Foundation of China (10304019, 10134010 and 10375080)
文摘The cluster target system was installed to the due position last year. Several test experiments such as the test of vacuum system, the calibration of the flux and the stability of system have been done after the installation and collimation of cluster internal target. However, there are two problems which hinder us from going further. One is the blocking of nozzle which results in the failure of a long-term system running; the other is the low pumping power for Hydrogen gases in the first stage of the cluster source cham-
基金Supported by the National Natural Science Foundation of China under Grant No.10304019,No.10134010 and No. 103750
文摘In highly charged ions(HCI)-atom collisions, many electrons are active and much more channels are opened, and the collision dynamics therefore is much more complicated. Because of the complexity originated from many active electrons which are involved in HCI and atoms collisions, the full quantum treatment is rather difficult, whereas the simple classical over-the-barrier models and semiempirical
基金National Natural Science Foundation of China(11604345,11611530684,11674333,11774356)。
文摘Radiative electron capture(REC)and nonradiative capture(NRC)are two competing mechanisms in relativistic collisions of highly charged ions with atoms[1].REC means electron transfer from target to projectile with the emission of one photon for satisfying energy and momentum conservation laws.
文摘In collisions between energetic highly charged ions and atoms,the ions could remove the electrons of the target atoms,or be excited into high-level states.In the first case,the target electrons not only be captured into ground and excited states of the projectile ions,but also be ionized to free.Non-radiative capture(NRC)and radiative electron capture(REC)are two competing mechanisms in fast collisions[1].NRC means electron transfer from a bound state of the target to a bound states of the projectile without the emission of radiation;REC is produced with simultaneous the emission of photon for satisfying energy and momentum conservation laws.The physical essence is the competition between the“electron-nucleus”interaction and the“electron-vacuum”interaction.NRC is dominant in collisions of high-Z ions with heavy target atoms at moderate energies.REC entirely determine the electron capture channel for high collision velocities and light targets[1].Measuring the relative strength of the projectile x-ray emission associated with electron capture could determine state-selective population,angular distribution of single capture Ly 1 or double capture Kα1 and Kα2,would provide new detailed information on the dynamics of ion-atom collisions and atomic structure studies[1].
