The absolute current distribution is usually the most desirable parameter in experiments involving a charged particle beam. The Faraday cup array technique, a direct measurement of the absolute current distribution, h...The absolute current distribution is usually the most desirable parameter in experiments involving a charged particle beam. The Faraday cup array technique, a direct measurement of the absolute current distribution, has been developed both in one dimension[1] and two dimensions[2], providing a great advantage in terms of convenience. In this technique, a many-channel picoammeter (up to 128 channels) is necessary.展开更多
The experiments with an internal target at a storage ring have many advantages. However, it is difficult to determine the absolute cross section of a reaction where luminosity cannot be simply established through macr...The experiments with an internal target at a storage ring have many advantages. However, it is difficult to determine the absolute cross section of a reaction where luminosity cannot be simply established through macroscopic measurements. Here we present an experimental determination of the effective target thickness from the beam energy losses at the internal target in HIRFL-CSRe. The measurements here are expected to provide the accurate target thickness and luminosity for the absolute cross-section study on future internal target experiments, and also provide some reference values for the study of beam loss mechanism of the heavy ion at HIRFL-CSRe.展开更多
Since the unexpected guiding effect of low energy ions by PET nanocapillaries was reported in the last decade[1], the self-organized charge-up on insulating surface is employed to realize a self-adaptive manipulation ...Since the unexpected guiding effect of low energy ions by PET nanocapillaries was reported in the last decade[1], the self-organized charge-up on insulating surface is employed to realize a self-adaptive manipulation of charged particle beams[2–4]. Considerable work (see Ref. [5] and references therein) has been done to investigate slow highly charged ions (SHCIs) interacting with inner surface of various insulating capillaries[5].展开更多
Double K-shell ionization of atoms by collisions with charged ions is one of typical two-electron processes andattracts considerable attention both in term of basic theory and experiment. Radiative de-excitation of th...Double K-shell ionization of atoms by collisions with charged ions is one of typical two-electron processes andattracts considerable attention both in term of basic theory and experiment. Radiative de-excitation of the doubleK-shell vacancy states of atoms leads to the emission of so called K X-ray hyper-satellites (Kh,Kh . . . )[1], whichgives us the insight into the decay modes of multiply ionized ions as well as the ionization processes during ion-atomcollisions. Contrary to the long-winded and difficult experiments with heavy target due to the low detection efficiencyof K X-ray hyper-satellites with crystal spectrometers[2??4], the bulk of knowledge concerning double K-shellionization in ion-atom collisions has been obtained for light target.展开更多
The guiding effect of 3 keV Ne7+ ions passing through an insulating PET nanocapillaries was found in 2002by N. Stolterfoht et al[1]. Since then considerable work[2] has been done to investigate slow highly charged ion...The guiding effect of 3 keV Ne7+ ions passing through an insulating PET nanocapillaries was found in 2002by N. Stolterfoht et al[1]. Since then considerable work[2] has been done to investigate slow highly charged ions(HCIs) interacting with inner surfaces of various insulating capillaries. It has been shown that the guiding effect isprevalent in the transmission of slow HCIs.Similar guiding phenomena were also observed for electrons transmitted through capillaries (see, e.g., Ref. [3-5]).However, the experiments showed that transmission efficiency of electrons was significantly lower than that of HCIs.Moreover, it revealed that portion of the transmitted electrons suffered significant energy-loss.展开更多
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
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 fast heavy ions and atoms,the strong Coulomb field of one of collision partners can cause inner-shell multiple-ionization of the second one[1].The high-resolution measurements of emitted X-rays i...In collisions between fast heavy ions and atoms,the strong Coulomb field of one of collision partners can cause inner-shell multiple-ionization of the second one[1].The high-resolution measurements of emitted X-rays in the collision are one of the most effective methods to study the multivacancy configurations in atoms or ions as well as the dynamics of the multiple ionization process.The energy shifts of X-rays from states with different vacancy configuration could be large[2].For example,the energy of the argon K hypersatellite and satellite line is between 2.9 and 3.8 keV,and the energy shift causing by per L hole is close to 20 eV[3].In order to simultaneous detection of the emitted X-rays over a wide energy range,thus avoiding the problem of changing the angle of crystal and position of the CCD in one collision system,a wide-angle and high-efficiency X-ray spectrometer based on flat HOPG(Highly Oriented Pyrolytic Graphite)crystal was developed.Due to X-ray from multi-ionized atoms.展开更多
Although great attention has been paid to study the guiding effects of charged ions through insulating nanocapillaries or a single microcapillary[1]since the pioneering work of Stolterfoht et al.in 2002[2],the same hi...Although great attention has been paid to study the guiding effects of charged ions through insulating nanocapillaries or a single microcapillary[1]since the pioneering work of Stolterfoht et al.in 2002[2],the same high standard of reproducibility and accuracy among different laboratory cannot be expected because the bulk and surface conductivities of an insulating material are often not well characterized and depend strongly on the working conditions.In other words,the guiding processes are rather random than controllable.In addition,with the energy increasing,the incomplete guiding effect[3;4]limits the application of guiding a swift ion beam in a self-organizing way.展开更多
文摘The absolute current distribution is usually the most desirable parameter in experiments involving a charged particle beam. The Faraday cup array technique, a direct measurement of the absolute current distribution, has been developed both in one dimension[1] and two dimensions[2], providing a great advantage in terms of convenience. In this technique, a many-channel picoammeter (up to 128 channels) is necessary.
基金National Natural Science Foundation of China (11105201, U1532130, U1332206)
文摘The experiments with an internal target at a storage ring have many advantages. However, it is difficult to determine the absolute cross section of a reaction where luminosity cannot be simply established through macroscopic measurements. Here we present an experimental determination of the effective target thickness from the beam energy losses at the internal target in HIRFL-CSRe. The measurements here are expected to provide the accurate target thickness and luminosity for the absolute cross-section study on future internal target experiments, and also provide some reference values for the study of beam loss mechanism of the heavy ion at HIRFL-CSRe.
文摘Since the unexpected guiding effect of low energy ions by PET nanocapillaries was reported in the last decade[1], the self-organized charge-up on insulating surface is employed to realize a self-adaptive manipulation of charged particle beams[2–4]. Considerable work (see Ref. [5] and references therein) has been done to investigate slow highly charged ions (SHCIs) interacting with inner surface of various insulating capillaries[5].
文摘Double K-shell ionization of atoms by collisions with charged ions is one of typical two-electron processes andattracts considerable attention both in term of basic theory and experiment. Radiative de-excitation of the doubleK-shell vacancy states of atoms leads to the emission of so called K X-ray hyper-satellites (Kh,Kh . . . )[1], whichgives us the insight into the decay modes of multiply ionized ions as well as the ionization processes during ion-atomcollisions. Contrary to the long-winded and difficult experiments with heavy target due to the low detection efficiencyof K X-ray hyper-satellites with crystal spectrometers[2??4], the bulk of knowledge concerning double K-shellionization in ion-atom collisions has been obtained for light target.
文摘The guiding effect of 3 keV Ne7+ ions passing through an insulating PET nanocapillaries was found in 2002by N. Stolterfoht et al[1]. Since then considerable work[2] has been done to investigate slow highly charged ions(HCIs) interacting with inner surfaces of various insulating capillaries. It has been shown that the guiding effect isprevalent in the transmission of slow HCIs.Similar guiding phenomena were also observed for electrons transmitted through capillaries (see, e.g., Ref. [3-5]).However, the experiments showed that transmission efficiency of electrons was significantly lower than that of HCIs.Moreover, it revealed that portion of the transmitted electrons suffered significant energy-loss.
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].
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 fast heavy ions and atoms,the strong Coulomb field of one of collision partners can cause inner-shell multiple-ionization of the second one[1].The high-resolution measurements of emitted X-rays in the collision are one of the most effective methods to study the multivacancy configurations in atoms or ions as well as the dynamics of the multiple ionization process.The energy shifts of X-rays from states with different vacancy configuration could be large[2].For example,the energy of the argon K hypersatellite and satellite line is between 2.9 and 3.8 keV,and the energy shift causing by per L hole is close to 20 eV[3].In order to simultaneous detection of the emitted X-rays over a wide energy range,thus avoiding the problem of changing the angle of crystal and position of the CCD in one collision system,a wide-angle and high-efficiency X-ray spectrometer based on flat HOPG(Highly Oriented Pyrolytic Graphite)crystal was developed.Due to X-ray from multi-ionized atoms.
文摘Although great attention has been paid to study the guiding effects of charged ions through insulating nanocapillaries or a single microcapillary[1]since the pioneering work of Stolterfoht et al.in 2002[2],the same high standard of reproducibility and accuracy among different laboratory cannot be expected because the bulk and surface conductivities of an insulating material are often not well characterized and depend strongly on the working conditions.In other words,the guiding processes are rather random than controllable.In addition,with the energy increasing,the incomplete guiding effect[3;4]limits the application of guiding a swift ion beam in a self-organizing way.
