Angular and mass resolved energy distribution measurements with a gallium liquid metal ion source

International Nuclear Information System (INIS)

Marriott, Philip

1987-06-01

Ionisation and energy broadening mechanisms relevant to liquid metal ion sources are discussed. A review of experimental results giving a picture of source operation and a discussion of the emission mechanisms thought to occur for the ionic species and droplets emitted is presented. Further work is suggested by this review and an analysis system for angular and mass resolved energy distribution measurements of liquid metal ion source beams has been constructed. The energy analyser has been calibrated and a series of measurements, both on and off the beam axis, of 69 Ga + , Ga ++ and Ga 2 + ions emitted at various currents from a gallium source has been performed. A comparison is made between these results and published work where possible, and the results are discussed with the aim of determining the emission and energy spread mechanisms operating in the gallium liquid metal ion source. (author)

Measurement of the energy loss of heavy ions in laser-produced plasmas

Energy Technology Data Exchange (ETDEWEB)

Knobloch-Maas, Renate

2009-11-25

The interaction of ions with plasma is not yet fully understood today, although it is important for inertial fusion technology. During recent years, the energy loss of heavy ions in plasma has therefore been a subject of research in the Laser and Plasma Physics group of Darmstadt University of Technology. Several experiments were carried out at the Gesellschaft fuer Schwerionenforschung (GSI) in Darmstadt using laser-created plasma, thereby taking advantage of the unique combination of GSI's accelerator facility and the laser system nhelix, which is also described in this work. The experiments focus on the measurement of the energy loss of medium heavy ions in a plasma created by directly heating a thin carbon foil with the nhelix laser, at an energy of about 50 J. In order to measure the energy loss using a time-of-flight method, a stop detector is used to register the arrival of the ion pulses after passing the plasma and a 12 m drift space. At the beginning of the work on this thesis, the ion detector types formerly used were found to be inadequately suited to the difficult task; this was changed during this thesis. The ion detector has to be able to temporarily resolve ion pulses with a frequency of 108 MHz and a width (FWHM) of 3 ns at a very low current. It also has to withstand the X-ray burst from the plasma with a dead time shorter than the difference between the X-ray and the ion time of flight between the plasma and the detector. In order to satisfy these and other demands, a new diamond detector was designed and has now been used for several measurements. In addition to the new detector, other improvements were made concerning the diagnostics and the laser. The laser-created plasma now reaches a maximum temperature exceeding 200 eV and a free electron density of up to 10{sup 22} cm{sup -3}. With this greatly improved setup, energy loss data could be obtained with a temporal resolution several times better than before, using an ion beam with a

Measurement of the energy loss of heavy ions in laser-produced plasmas

International Nuclear Information System (INIS)

Knobloch-Maas, Renate

2009-01-01

The interaction of ions with plasma is not yet fully understood today, although it is important for inertial fusion technology. During recent years, the energy loss of heavy ions in plasma has therefore been a subject of research in the Laser and Plasma Physics group of Darmstadt University of Technology. Several experiments were carried out at the Gesellschaft fuer Schwerionenforschung (GSI) in Darmstadt using laser-created plasma, thereby taking advantage of the unique combination of GSI's accelerator facility and the laser system nhelix, which is also described in this work. The experiments focus on the measurement of the energy loss of medium heavy ions in a plasma created by directly heating a thin carbon foil with the nhelix laser, at an energy of about 50 J. In order to measure the energy loss using a time-of-flight method, a stop detector is used to register the arrival of the ion pulses after passing the plasma and a 12 m drift space. At the beginning of the work on this thesis, the ion detector types formerly used were found to be inadequately suited to the difficult task; this was changed during this thesis. The ion detector has to be able to temporarily resolve ion pulses with a frequency of 108 MHz and a width (FWHM) of 3 ns at a very low current. It also has to withstand the X-ray burst from the plasma with a dead time shorter than the difference between the X-ray and the ion time of flight between the plasma and the detector. In order to satisfy these and other demands, a new diamond detector was designed and has now been used for several measurements. In addition to the new detector, other improvements were made concerning the diagnostics and the laser. The laser-created plasma now reaches a maximum temperature exceeding 200 eV and a free electron density of up to 10 22 cm -3 . With this greatly improved setup, energy loss data could be obtained with a temporal resolution several times better than before, using an ion beam with a diameter of only

Surface characterization by energy distribution measurements of secondary electrons and of ion-induced electrons

International Nuclear Information System (INIS)

Bauer, H.E.; Seiler, H.

1988-01-01

Instruments for surface microanalysis (e.g. scanning electron or ion microprobes, emission electron or ion microscopes) use the current of emitted secondary electrons or of emitted ion-induced electrons for imaging of the analysed surface. These currents, integrating over all energies of the emitted low energy electrons, are however, not well suited to surface analytical purposes. On the contrary, the energy distribution of these electrons is extremely surface-sensitive with respect to shape, size, width, most probable energy, and cut-off energy. The energy distribution measurements were performed with a cylindrical mirror analyser and converted into N(E), if necessary. Presented are energy spectra of electrons released by electrons and argon ions of some contaminated and sputter cleaned metals, the change of the secondary electron energy distribution from oxidized aluminium to clean aluminium, and the change of the cut-off energy due to work function change of oxidized aluminium, and of a silver layer on a platinum sample. The energy distribution of the secondary electrons often shows detailed structures, probably due to low-energy Auger electrons, and is broader than the energy distribution of ion-induced electrons of the same object point. (author)

Measurement of energy deposition near heavy ion tracks

International Nuclear Information System (INIS)

Metting, N.F.; Brady, L.A.; Rossi, H.H.; Kliauga, P.J.; Howard, J.; Wong, M.; Schimmerling, W.; Rapkin, M.

1985-01-01

In November of 1982 work was begun in collaboration with Columbia University and Lawrence Berkeley Laboratory to use microdosimetric methods to measure energy deposition of heavy ions produced at LBL's Bevalac Biomedical Facility. Last year the authors reported preliminary results indicating that secondary charged particle equilibrium was probably obtained using this experimental setup, but that there seemed to be poor spatial resolution in the solid state position-sensitive detector. Further analysis of the measurements taken in August 1983 shows that because of this electronic noise in the position-sensitive detector, only the 56 Fe data yielded useful microdosimetric spectra

Binding energies of cluster ions

International Nuclear Information System (INIS)

Parajuli, R.; Matt, S.; Scheier, P.; Echt, O.; Stamatovic, A.; Maerk, T.D.

2002-01-01

The binding energy of charged clusters may be measured by analyzing the kinetic energy released in the metastable decay of mass selected parent ions. Using finite heat bath theory to determine the binding energies of argon, neon, krypton, oxygen and nitrogen from their respective average kinetic energy released were carried out. A high-resolution double focussing two-sector mass spectrometer of reversed Nier-Johnson type geometry was used. MIKE ( mass-analysed ion kinetic energy) were measured to investigate decay reactions of mass-selected ions. For the inert gases neon (Ne n + ), argon (Ar n + ) and krypton (Kr n + ), it is found that the binding energies initially decrease with increasing size n and then level off at a value above the enthalpy of vaporization of the condensed phase. Oxygen cluster ions shown a characteristic dependence on cluster size (U-shape) indicating a change in the metastable fragmentation mechanism when going from the dimer to the decamer ion. (nevyjel)

Medium energy ion scattering (MEIS)

International Nuclear Information System (INIS)

Dittmann, K.; Markwitz, A.

2009-01-01

This report gives an overview about the technique and experimental study of medium energy ion scattering (MEIS) as a quantitative technique to determine and analyse the composition and geometrical structure of crystalline surfaces and near surface-layers by measuring the energy and yield of the backscattered ions. The use of a lower energy range of 50 to 500 keV accelerated ions impinging onto the target surface and the application of a high-resolution electrostatic energy analyser (ESA) makes medium energy ion scattering spectroscopy into a high depth resolution and surface-sensitive version of RBS with less resulting damage effects. This report details the first steps of research in that field of measurement technology using medium energetic backscattered ions detected by means of a semiconductor radiation detector instead of an ESA. The study of medium energy ion scattering (MEIS) has been performed using the 40 keV industrial ion implanter established at GNS Sciences remodelled with supplementary high voltage insulation for the ion source in order to apply voltages up to 45 kV, extra apertures installed in the beamline and sample chamber in order to set the beam diameter accurately, and a semiconductor radiation detector. For measurement purposes a beam of positive charged helium ions accelerated to an energy of about 80 keV has been used impinging onto target surfaces of lead implanted into silicon (PbSi), scandium implanted into aluminium (ScAl), aluminium foil (Al) and glassy carbon (C). First results show that it is possible to use the upgraded industrial implanter for medium energy ion scattering. The beam of 4 He 2+ with an energy up to 88 keV has been focussed to 1 mm in diameter. The 5 nA ion beam hit the samples under 2 x 10 -8 mbar. The results using the surface barrier detector show scattering events from the samples. Cooling of the detector to liquid nitrogen temperatures reduced the electronic noise in the backscattering spectrum close to zero. A

The evolution of ring current ion energy density and energy content during geomagnetic storms based on Van Allen Probes measurements

International Nuclear Information System (INIS)

Zhao, H.; University of Colorado, Boulder, CO; Li, X.; University of Colorado, Boulder, CO; Baker, D. N.

2015-01-01

Enabled by the comprehensive measurements from the Magnetic Electron Ion Spectrometer (MagEIS), Helium Oxygen Proton Electron mass spectrometer (HOPE), and Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) instruments onboard Van Allen Probes in the heart of the radiation belt, the relative contributions of ions with different energies and species to the ring current energy density and their dependence on the phases of geomagnetic storms are quantified. The results show that lower energy (<50 keV) protons enhance much more often and also decay much faster than higher-energy protons. During the storm main phase, ions with energies <50 keV contribute more significantly to the ring current than those with higher energies; while the higher-energy protons dominate during the recovery phase and quiet times. The enhancements of higher-energy proton fluxes as well as energy content generally occur later than those of lower energy protons, which could be due to the inward radial diffusion. For the 29 March 2013 storm we investigated in detail that the contribution from O + is ~25% of the ring current energy content during the main phase and the majority of that comes from <50 keV O + . This indicates that even during moderate geomagnetic storms the ionosphere is still an important contributor to the ring current ions. Using the Dessler-Parker-Sckopke relation, the contributions of ring current particles to the magnetic field depression during this geomagnetic storm are also calculated. In conclusion, the results show that the measured ring current ions contribute about half of the Dst depression.

Measurement of residual radioactivity in cooper exposed to high energy heavy ion beam

Energy Technology Data Exchange (ETDEWEB)

Kim, Eunjoo; Nakamura, Takashi [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center; Uwamino, Yoshitomo; Ito, Sachiko; Fukumura, Akifumi

1999-03-01

The residual radioactivities produced by high energy heavy ions have been measured using the heavy ion beams of the Heavy Ion Medical Accelerator (HIMAC) at National Institute of Radiological Sciences. The spatial distribution of residual radioactivities in 3.5 cm, 5.5 cm and 10 cm thick copper targets of 10 cm x 10 cm size bombarded by 290 MeV/u, 400 MeV/u-{sup 12}C ion beams and 400 MeV/u-{sup 20}Ne ion beam, respectively, were obtained by measuring the gamma-ray activities of 0.5 mm thick copper foil inserted in the target with a high purity Ge detector after about 1 hour to 6 hours irradiation. (author)

E parallel B energy-mass spectrograph for measurement of ions and neutral atoms

International Nuclear Information System (INIS)

Funsten, H.O.; McComas, D.J.; Scime, E.E.

1997-01-01

Real-time measurement of plasma composition and energy is an important diagnostic in fusion experiments. The Thomson parabola spectrograph described here utilizes an electric field parallel to a magnetic field (E parallel B) and a two-dimensional imaging detector to uniquely identify the energy-per-charge and mass-per-charge distributions of plasma ions. An ultrathin foil can be inserted in front of the E parallel B filter to convert neutral atoms to ions, which are subsequently analyzed using the E parallel B filter. Since helium exiting an ultrathin foil does not form a negative ion and hydrogen isotopes do, this spectrograph allows unique identification of tritium ions and neutrals even in the presence of a large background of 3 He. copyright 1997 American Institute of Physics

Low energy RBS-channeling measurement system with the use of a time-of-flight scattered ion detector

Energy Technology Data Exchange (ETDEWEB)

Hasegawa, Masataka; Kobayashi, Naoto; Hayashi, Nobuyuki [Electrotechnical Lab., Tsukuba, Ibaraki (Japan)

1996-07-01

We have developed a low energy Rutherford backscattering spectrometry-ion channeling measurement system for the analysis of thin films and solid surfaces with the use of several tens keV hydrogen ions and a time-of-flight particle energy spectrometer. For the detection of the scattered ions new TOF spectrometer has been developed, which consists of two micro-channel-plate detectors. The pulsing of the primary ion beam is not necessary for this type of TOF measurement, and it is possible to observe continues scattered ion beams. The dimension of whole system is very compact compared to the conventional RBS-channeling measurement system with the use of MeV He ions. The energy resolution, {delta} E/E, for 25 keV H{sup +} was 4.1%, which corresponds to the depth resolution of 4.8 nm for silicon. The depth resolution of our system is better than that of conventional RBS system with MeV helium ions and solid state detectors. We have demonstrated the ion channeling measurement by this system with 25 keV hydrogen ions. The system can be available well to the analysis of thin films and solid surfaces with the use of the ion channeling effect. The observation of the reaction between Fe and hydrogen terminated silicon surface was also demonstrated. (J.P.N.)

Energy measurement of fast ions trapped in the toroidal magnetic field ripple of Tore Supra during ICRF heating

International Nuclear Information System (INIS)

Basiuk, V.; Becoulet, A.; Grisolia, C.; Hutter, T.; Mayaux, G.; Martin, G.; Saoutic, B.; Vartanian, S.

1995-01-01

Direct losses of ions trapped in the toroidal field ripple of Tore Supra using two techniques were made. The first (DRIPPLE I) correlates the ion loss current measured by an electric probe with the ion loss power measured by a calorimeter. As the calorimeter integrates over all particle energies and time, it yields only the averaged lost ion energy. The second technique (DRIPPLE II), still under development, is a Faraday cup positioned and filtered so as to select ions by their Larmor radius. The currents measured are small (1-100 nA), and improvements in instrumentation are needed to take full advantage of the data, but the preliminary results are still useful. During ICRH (hydrogen minority regime, resonance on axis) a direct correlation between the lost ion mean energy and the density of hydrogen was seen. The energy increased when the hydrogen minority density decreased. Moreover, the line averaged density and the lower hybrid heating (LH) had also an effect on fast ion losses. (authors). 3 refs., 7 figs

Derivation of the radial profile of ion temperature from the measured energy spectra of charge-exchanged neutrals

Energy Technology Data Exchange (ETDEWEB)

Nakamura, K; Hiraki, N; Toi, K; Itoh, S

1980-01-01

In the TRIAM-1 tokamak the energy spectra of charge-exchanged neutrals are observed by scanning the neutral energy analyzer vertically. The measured ion temperature obtained from the only energy spectrum observed in the peripheral region is much higher than that predicted by the neoclassical transport theory because of reflection (backscattering) of neutrals at the wall. The actual ion temperature profile is derived from all observed energy spectra by the numerical code in which a wall-reflection effect of neutrals and an impermeability of plasma are taken into account. The reflection coefficient is adjusted so that the calculated ion temperature profile should be the best fit for the ion temperatures measured by the Doppler broadening of the visible lines He II 4686 A and H-alpha at the relevant radial positions.

Collisions of low-energy multicharged ions

International Nuclear Information System (INIS)

Phaneuf, R.A.; Crandall, D.H.

1981-01-01

Experimental measurements of cross sections for collisions of multiply charged ions with atoms at the lowest attainable collision energies are reported. Emphasis is on electron capture from hydrogen atoms by multiply charged ions at energies below 1 keV/amu. The principal effort is the development of a merged-ion-atom-beams apparatus for studies down to 1 eV/amu relative energy

Beam profile measurement with CR-39 track detector for low-energy ions

CERN Document Server

Sato, F; Tanaka, T; Iida, T; Yamauchi, T; Oda, K

1999-01-01

A CR-39 track detector was successfully used to measure the outline of thin low-energy ion beams. After the etching, the surface of the detector was examined with an observation system composed of a Normarski microscope, a CCD camera and a digital image processing computer. Beam images obtained with the system were in good agreement on the outline of the beam formed with a beam aperture. Also, the resolving power in the beam outline measurement was roughly explained from the consideration of the ion range and the etch-pit growth in the chemical etching for the CR-39 detector.

Derivation of the radial profile of ion temperature from the 'measured' energy spectra of charge-exchanged neutrals

International Nuclear Information System (INIS)

Nakamura, Kazuo; Hiraki, Naoji; Toi, Kazuo; Itoh, Satoshi

1980-01-01

In the TRIAM-1 tokamak the energy spectra of charge-exchanged neutrals are observed by scanning the neutral energy analyzer vertically. The ''measured'' ion temperature obtained from only energy spectrum observed in the peripheral region is much higher than that predicted by the neoclassical transport theory because of reflection (backscattering) of neutrals at the wall. The ''actual'' ion temperature profile is derived from all observed energy spectra by using the numerical code in which a wall-reflection effect of neutrals and an impermeability of plasma are taken into account. In this numerical analysis, the reflection coefficient is adjusted so that the above calculated ion temperature profile should be best fit for the ion temperatures measured by the Doppler broadening of the visible lines HeII 4686 A and H sub(α) at the relevant radial positions. (author)

Derivation of the radial profile of ion temperature from the 'measured' energy spectra of charge-exchanged neutrals

Energy Technology Data Exchange (ETDEWEB)

Nakamura, K; Hiraki, N; Toi, K; Itoh, S [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

1980-07-01

In the TRIAM-1 tokamak the energy spectra of charge-exchanged neutrals are observed by scanning the neutral energy analyzer vertically. The ''measured'' ion temperature obtained from only energy spectrum observed in the peripheral region is much higher than that predicted by the neoclassical transport theory because of reflection (backscattering) of neutrals at the wall. The ''actual'' ion temperature profile is derived from all observed energy spectra by using the numerical code in which a wall-reflection effect of neutrals and an impermeability of plasma are taken into account. In this numerical analysis, the reflection coefficient is adjusted so that the above calculated ion temperature profile should be best fit for the ion temperatures measured by the Doppler broadening of the visible lines HeII 4686 A and H sub(..cap alpha..) at the relevant radial positions.

Flow direction variations of low energy ions as measured by the ion electron sensor (IES) flying on board of Rosetta

Science.gov (United States)

Szegö, Karoly; Nemeth, Zoltan; Foldy, Lajos; Burch, James L.; Goldstein, Raymond; Mandt, Kathleen; Mokashi, Prachet; Broiles, Tom

2015-04-01

The Ion Electron Sensor (IES) simultaneously measures ions and electrons with two separate electrostatic plasma analyzers in the energy range of 4 eV- 22 keV for ions. The field of view is 90ox360o, with angular resolution 5ox45o for ions, with a sector containing the solar wind being further segmented to 5o × 5o. IES has operated continuously since early 2014. In the ion data a low energy (energy ions. Here we analyze the arrival direction of this low energy component. The origin of these low energy ions is certainly the ionized component of the neutral gas emitted due to solar activity from comet 67P/Churiumov-Gerasimenko. The low energy component in general shows a 6h periodicity due to cometary rotation. The data show, however, that the arrival direction of the low energy ions is smeared both in azimuth and elevation, due possibly to the diverse mechanisms affecting these ions. One of these effects is the spacecraft potential (~-10V), which accelerates the ions towards the spacecraft omnidirectionally. To characterize the flow direction in azimuth-elevation, we have integrated over the lowest 8 energy channels using weighted energy: sum(counts * energy)/sum(counts); and considered only cases when the counts are above 30. When we apply higher cut for counts, the flow direction became more definite. For this analysis we use data files where the two neighbouring energy values and elevation values are collapsed; and the azimuthal resolution is 45o, that is the solar wind azimuthal segmentation is also collapsed. Here we use day 2014.09.11. as illustration. On that day a solar wind shock reached the spacecraft at about ~10 UT. After the shock transition the energy of the solar wind became higher, and after ~12 UT the flow direction of the solar wind fluctuated, sometimes by 35o. On this day Rosetta flew at about 29.3-29.6 km from the nucleus. In the azimuth-elevation plots summed over "weighted energy" (as defined above) we were able to identify two flow directions

Recent measurements of low energy charge exchange cross sections for collisions of multicharged ions on neutral atoms and molecules

International Nuclear Information System (INIS)

Havener, Charles C.

2001-01-01

At ORNL Multicharged Ion Research Facility (MIRF), charge exchange (CX) cross sections have been measured for multicharged ions (MCI) on neutral atoms and molecules. The ORNL ion-atom merged-beam apparatus was used to measure single electron capture by MCI from H at eV/amu energies. A gas cell was used to measure single and double electron capture by MCI from a variety of molecular targets at keV collision energies. The merged-beams experiment has been successful in providing benchmark total electron capture measurements for several collision systems with a variety of multicharged ions on H or D

Ion temperature measurement by neutral energy analyzer in high-field tokamak TRIAM-1

Energy Technology Data Exchange (ETDEWEB)

Nakamura, K; Hiraki, N; Toi, K; Itoh, S [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

1980-02-01

The measurement of the ion temperature of the TRIAM-1 tokamak plasma is carried out by using a seven-channel neutral energy analyzer. The temporal and spatial variations of the ion temperature have been obtained with the spatial resolution of +-4.3 mm and the temporal resolution of 100 ..mu..sec. The energy range of the analyzed neutral particles is from 0.2 to 8 keV. The energy spectrum in the TRIAM-1 plasma without the strong gas puffing usually consists of two-component Maxwellian; the one represents the thermal part which is a superposition of the contribution from a hot region (T sub(i) = 100 - 300 eV) and that from an edge region (T sub(i) asymptotically equals 50 eV), and the other represents the superthermal part (T sub(i) asymptotically equals 1 keV). The neutral particle energy spectra at several vertical positions are obtained by scanning the analyzer in the vertical direction. From those spectra, the radial profile of the ion temperature is derived by means of the nonlinear optimization method.

Measurement of electron- and ion beam energies and currents in a plasma focus discharge

International Nuclear Information System (INIS)

Yamamoto, Toshikazu; Kondoh, Yoshiomi; Shimoda, Katsuji; Hirano, Katsumi

1982-01-01

Measurements of energetic particle beams in a plsma focus with a Mather type device are presented. Rogowski coils are used for time-resolved measurement, and solid-state nuclear track detectors for time-integrated measurement of the beams. In the upstream direction with respect to the discharge current, only the electron beam with the maximum current of several kA was detected, which was approximately one percent of the discharge current. The electron energies of the beam were spread from 0.1 to 1 MeV. In the downstream direction, two successive emissions of ions were observed. The first emission had an extremely high energy of the order of some MeV and a low beam current of less than 10 A. The second emission, the main part of the ion beam, with energies of 100 - 800 keV, followed the first one with a time lag of several tens of nanoseconds, and the beam current reached several tens of amperes. (author)

First β-ν correlation measurement from the recoil-energy spectrum of Penning trapped Ar35 ions

Science.gov (United States)

Van Gorp, S.; Breitenfeldt, M.; Tandecki, M.; Beck, M.; Finlay, P.; Friedag, P.; Glück, F.; Herlert, A.; Kozlov, V.; Porobic, T.; Soti, G.; Traykov, E.; Wauters, F.; Weinheimer, Ch.; Zákoucký, D.; Severijns, N.

2014-08-01

We demonstrate a novel method to search for physics beyond the standard model by determining the β-ν angular correlation from the recoil-ion energy distribution after β decay of ions stored in a Penning trap. This recoil-ion energy distribution is measured with a retardation spectrometer. The unique combination of the spectrometer with a Penning trap provides a number of advantages, e.g., a high recoil-ion count rate and low sensitivity to the initial position and velocity distribution of the ions and completely different sources of systematic errors compared to other state-of-the-art experiments. Results of a first measurement with the isotope Ar35 are presented. Although currently at limited precision, we show that a statistical precision of about 0.5% is achievable with this unique method, thereby opening up the possibility of contributing to state-of-the-art searches for exotic currents in weak interactions.

First measurements of the ion energy distribution at the divertor strike point during DIII-D disruptions

International Nuclear Information System (INIS)

Parks, P.B.; Brooks, N.H.; West, W.P.; Wong, C.P.C.; Bastasz, R.; Wampler, W.R.; Whyte, D.

1995-12-01

Plasma/wall interaction studies are being carried out using the Divertor Materials Exposure System (DiMES) on DIII-D. The objective of the experiment is to determine the kinetic energy and flux of deuterium ions reaching the divertor target during argon-induced radiative disruptions. The experiment utilizes a special slotted ion analyzer mounted over a Si sample to collect the fast charge-exchange (CX) deuterium neutrals emitted within the recycled cold neutral layer (CNL) which serves as a CX target for the incident ions. A theoretical interpretation of the experiment reveals a strong forward pitch-angle dependence in the approaching ion distribution function. The depth distribution of the trapped D in the Si sample was measured using low-energy direct recoil spectroscopy. Comparison with the TRIM code using monoenergetic ions indicated that the best fit to the data was obtained for an ion energy of 100 eV

A quadrupole ion trap as low-energy cluster ion beam source

CERN Document Server

Uchida, N; Kanayama, T

2003-01-01

Kinetic energy distribution of ion beams was measured by a retarding field energy analyzer for a mass-selective cluster ion beam deposition system that uses a quadrupole ion trap as a cluster ion beam source. The results indicated that the system delivers a cluster-ion beam with energy distribution of approx 2 eV, which corresponded well to the calculation results of the trapping potentials in the ion trap. Using this deposition system, mass-selected hydrogenated Si cluster ions Si sub n H sub x sup + were actually deposited on Si(111)-(7x7) surfaces at impact kinetic energy E sub d of 3-30 eV. Observation by using a scanning tunneling microscope (STM) demonstrated that Si sub 6 H sub x sup + cluster ions landed on the surface without decomposition at E sub d =3 eV, while the deposition was destructive at E sub d>=18 eV. (author)

An ion beam deceleration lens for ultra-low-energy ion bombardment of naked DNA

Energy Technology Data Exchange (ETDEWEB)

Thopan, P.; Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongkumkoon, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Suwannakachorn, D. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuldyuld@gmail.com [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

2013-07-15

Highlights: ► An ion beam deceleration lens was designed and constructed. ► The deceleration lens was installed and tested. ► The decelerated ion beam energy was measured using an electrical field. ► Decelerated ultra-low-energy ion beam bombarded naked DNA. ► Ion beam with energy of a few tens of eV could break DNA strands. -- Abstract: Study of low-energy ion bombardment effect on biological living materials is of significance. High-energy ion beam irradiation of biological materials such as organs and cells has no doubt biological effects. However, ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range. To investigate effects from very-low-energy ion bombardment on biological materials, an ion beam deceleration lens is necessary for uniform ion energy lower than keV. A deceleration lens was designed and constructed based on study of the beam optics using the SIMION program. The lens consisted of six electrodes, able to focus and decelerate primary ion beam, with the last one being a long tube to obtain a parallel uniform exiting beam. The deceleration lens was installed to our 30-kV bioengineering-specialized ion beam line. The final decelerated-ion energy was measured using a simple electrostatic field to bend the beam to range from 10 eV to 1 keV controlled by the lens parameters and the primary beam condition. In a preliminary test, nitrogen ion beam at 60 eV decelerated from a primary 20-keV beam bombarded naked plasmid DNA. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks. The study demonstrated that the ion bombardment with energy as low as several-tens eV was possible to break DNA strands and thus potential to cause genetic modification of biological cells.

An ion beam deceleration lens for ultra-low-energy ion bombardment of naked DNA

International Nuclear Information System (INIS)

Thopan, P.; Prakrajang, K.; Thongkumkoon, P.; Suwannakachorn, D.; Yu, L.D.

2013-01-01

Highlights: ► An ion beam deceleration lens was designed and constructed. ► The deceleration lens was installed and tested. ► The decelerated ion beam energy was measured using an electrical field. ► Decelerated ultra-low-energy ion beam bombarded naked DNA. ► Ion beam with energy of a few tens of eV could break DNA strands. -- Abstract: Study of low-energy ion bombardment effect on biological living materials is of significance. High-energy ion beam irradiation of biological materials such as organs and cells has no doubt biological effects. However, ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range. To investigate effects from very-low-energy ion bombardment on biological materials, an ion beam deceleration lens is necessary for uniform ion energy lower than keV. A deceleration lens was designed and constructed based on study of the beam optics using the SIMION program. The lens consisted of six electrodes, able to focus and decelerate primary ion beam, with the last one being a long tube to obtain a parallel uniform exiting beam. The deceleration lens was installed to our 30-kV bioengineering-specialized ion beam line. The final decelerated-ion energy was measured using a simple electrostatic field to bend the beam to range from 10 eV to 1 keV controlled by the lens parameters and the primary beam condition. In a preliminary test, nitrogen ion beam at 60 eV decelerated from a primary 20-keV beam bombarded naked plasmid DNA. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks. The study demonstrated that the ion bombardment with energy as low as several-tens eV was possible to break DNA strands and thus potential to cause genetic modification of biological cells

The measurements of light high-energy ions in NINA-2 experiment

Directory of Open Access Journals (Sweden)

A. Leonov

2007-10-01

Full Text Available The flux of energetic light ions at low altitude is both an important input and output for self-consistent calculations of albedo particles resulting from the interaction of trapped and cosmic ray particles, with the upper atmosphere. In addition, data on the flux of light ions are needed to evaluate radiation damages on space-borne instruments and on space mission crews. In spite of that, sources of data on the flux of energetic ions at LEO are roughly limited to the AP-8 model, CREME/CREME96 codes and the SAMPEX, NOAA/TIROS satellites. The existing and operational European SAC-C/ICARE and PROBA-1/SREM instruments could also be potential sources for proton data at LEO. Although AP-8 and SAMPEX/PSB97 may be publicly accessed through the SPENVIS, they exhibit an order of magnitude difference in low altitude proton fluxes and they do not contain helium fluxes. Therefore, improved light ion radiation models are still needed.

In this paper we present a procedure to identify and measure the energy of ions that are not stopped in the NINA-2 instrument. Moreover, problems related to particles that cross the instrument in the opposite direction are addressed and shown to be a possible cause of particle misidentification. Measuring fluxes of low abundance elements like energetic helium ions requires a good characterisation of all possible sources of backgrounds in the detector. Hints to determine the several contributions to the background are presented herein and may be applied to extract an order of magnitude of energetic ions fluxes from existing data sets, while waiting for dedicated high performance instruments.

The measurements of light high-energy ions in NINA-2 experiment

Directory of Open Access Journals (Sweden)

A. Leonov

2007-10-01

Full Text Available The flux of energetic light ions at low altitude is both an important input and output for self-consistent calculations of albedo particles resulting from the interaction of trapped and cosmic ray particles, with the upper atmosphere. In addition, data on the flux of light ions are needed to evaluate radiation damages on space-borne instruments and on space mission crews. In spite of that, sources of data on the flux of energetic ions at LEO are roughly limited to the AP-8 model, CREME/CREME96 codes and the SAMPEX, NOAA/TIROS satellites. The existing and operational European SAC-C/ICARE and PROBA-1/SREM instruments could also be potential sources for proton data at LEO. Although AP-8 and SAMPEX/PSB97 may be publicly accessed through the SPENVIS, they exhibit an order of magnitude difference in low altitude proton fluxes and they do not contain helium fluxes. Therefore, improved light ion radiation models are still needed. In this paper we present a procedure to identify and measure the energy of ions that are not stopped in the NINA-2 instrument. Moreover, problems related to particles that cross the instrument in the opposite direction are addressed and shown to be a possible cause of particle misidentification. Measuring fluxes of low abundance elements like energetic helium ions requires a good characterisation of all possible sources of backgrounds in the detector. Hints to determine the several contributions to the background are presented herein and may be applied to extract an order of magnitude of energetic ions fluxes from existing data sets, while waiting for dedicated high performance instruments.

Fully stripped heavy ion yield vs energy for Xe and Au ions

International Nuclear Information System (INIS)

Thieberger, P.; Wegner, H.E.; Alonzo, J.; Gould, H.; Anholt, R.E.; Meyerhof, W.E.

1985-01-01

The Bevalac is now capable of accelerating U-238 ions to approximately 1 GeV/amu and measurements have shown that fully stripped U-238 ions are produced with good yield at these energies. However, knowing the stripping yields at different energies for U-238 does not allow an accurate prediction for other, lower Z projectiles. Consequently, extensive stripping yield measurements were made for Au-197 and Xe-139 ions. In addition to the stripping measurements from the direct Bevalac beam, pickup measurements were also made with specially prepared bare, one electron, and two electron ions. Since many research groups are considering heavy ion storage rings and/or synchrotrons, the pickup cross section for bare ions is important to estimate beam lifetime in terms of the average machine vacuum. Since the Mylar target provides a pickup probability similar to air, a preliminary analysis of the Xe 54+ and U 92+ data are presented along with predictions for other ions ranging down to Fe 26+ . 11 refs., 3 figs., 1 tab

Fully stripped heavy ion yield vs energy for Xe and Au ions

Energy Technology Data Exchange (ETDEWEB)

Thieberger, P.; Wegner, H.E.; Alonzo, J.; Gould, H.; Anholt, R.E.; Meyerhof, W.E.

1985-01-01

The Bevalac is now capable of accelerating U-238 ions to approximately 1 GeV/amu and measurements have shown that fully stripped U-238 ions are produced with good yield at these energies. However, knowing the stripping yields at different energies for U-238 does not allow an accurate prediction for other, lower Z projectiles. Consequently, extensive stripping yield measurements were made for Au-197 and Xe-139 ions. In addition to the stripping measurements from the direct Bevalac beam, pickup measurements were also made with specially prepared bare, one electron, and two electron ions. Since many research groups are considering heavy ion storage rings and/or synchrotrons, the pickup cross section for bare ions is important to estimate beam lifetime in terms of the average machine vacuum. Since the Mylar target provides a pickup probability similar to air, a preliminary analysis of the Xe/sup 54 +/ and U/sup 92 +/ data are presented along with predictions for other ions ranging down to Fe/sup 26 +/. 11 refs., 3 figs., 1 tab.

Measurement of ion profiles in TFTR neutral beamlines

International Nuclear Information System (INIS)

Kamperschroer, J.H.; Grisham, L.R.; Kugel, H.W.; O'Connor, T.E.; Stevenson, T.N.; von Halle, A.; Williams, M.D.

1992-02-01

A technique is described whereby the ion dumps inside the TFTR Neutral Beam Test Stand were used to measure thermal profiles of the full-, half-, and third-energy ions. 136 thermocouples were installed on the full-energy ion dump, allowing full beam contours. Additional linear arrays across the widths of the half- and third-energy ion dumps provided a measure of the shape, in the direction parallel to the grid rails, of the half- and third-energy ions, and, hence, of the molecular ions extracted from the source. As a result of these measurements it was found that the magnet was more weakly focusing, by a factor of two, than expected, explaining past overheating of the full-energy ion dump. Hollow profiles on the half- and third-energy ion dumps were observed, suggesting that extraction of D 2 + and D 3 + are primarily from the edge of the ion source. If extraction of half-energy ions is from the edge of the accelerator, a divergence parallel to the grid rails of 0.6 degrees ±0.1 degrees results. It is postulated that a nonuniform gas profile near the accelerator is the cause of the hollow partial-energy ion profiles; the pressure being depressed over the accelerator by particles passing through this highly transparent structure. Primary electrons reaching the accelerator produce nonuniform densities of D 2 + through the ionization of this across the full-energy dump was examined as a means of reducing the power density. By unbalancing the current in the two coils of the magnet, on a shot by shot basis, by up to 2:1 ratio, it was possible to move the centerline of the full-energy ion beam sideways by ∼12.5 cm. The adoption of such a technique, with a ramp of the coil imbalance from 2:1 to 1:2 over a beam pulse, could reduce the power density by a factor of ≥1.5

An apparatus for measuring the energy and angular distribution of electrons in ion-atom collisions

International Nuclear Information System (INIS)

Gibson, D.K.; Petersen, M.C.E.

1978-07-01

There is a need for further data on the energy and angular distribution of electrons ejected from atoms and molecules by ion impact. An apparatus in which simultaneous measurements can be made of the energy and angular distributions of such electrons is described. The advantages of the apparatus are the possibility of fast data collection and the ability to make measurements over the whole range of scattering angle. Preliminary tests and a trial measurement with the apparatus are described

Electrostatic interaction between Interball-2 and the ambient plasma. 2. Influence on the low energy ion measurements with Hyperboloid

Directory of Open Access Journals (Sweden)

M. Hamelin

2002-03-01

Full Text Available The measurement of the thermal ion distributions in space is always strongly influenced by the ion motion through the complex 3D electrostatic potential structure built around a charged spacecraft. In this work, we study the related aberrations of the ion distribution detected on board, with special application to the case of the Hyperboloid instrument borne by the Interball-2 auroral satellite. Most of the time, the Interball-2 high altitude auroral satellite is charged at some non-negligible positive potential with respect to the ambient plasma, as shown in part 1; in consequence, the measurement of magnetospheric low energy ions (< 80 eV with the Hyperboloid instrument can be disturbed by the complex electric potential environment of the satellite. In the case of positive charging, as in previous experiments, a negative bias is applied to the Hyperboloid structure in order to reduce this effect and to keep as much as possible the opportunity to detect very low energy ions. Then, the ions reaching the Hyperboloid entrance windows would have travelled across a continuous huge electrostatic lens involving various spatial scales from ~ 10 cm (detector radius to ~ 10 m (satellite antennas. Neglecting space charge effects, we have computed the ion trajectories that are able to reach the Hyperboloid windows within their acceptance angles. There are three main results: (i for given values of the satellite potential, and for each direction of arrival (each window, we deduced the related energy cutoff; (ii we found that all ions in the energy channel, including the cutoff, can come from a large range of directions in the unperturbed plasma, especially when the solar panels or antennas act as electrostatic mirrors; (iii for higher energy channels, the disturbances are reduced to small angular shifts. Biasing of the aperture is not very effective with the Hyperboloid instrument (as on previous missions with instruments installed close to the spacecraft

Scintillation screen materials for beam profile measurements of high energy ion beams

Energy Technology Data Exchange (ETDEWEB)

Krishnakumar, Renuka

2016-06-22

{sub 2}O{sub 3}:Cr screen over 1000 pulses while slight saturation effects was noticed from some other screens. No considerable radiation induced damage for an irradiation by maximal fluence of 1.7 x 10{sup 11} cm{sup -2} Uranium ions was seen in the samples except the formation of point defects and color centers. Among the investigated screens P43 (Gd{sub 2}O{sub 2}S:Tb) powder seems to be a good candidate up to certain energy deposition threshold while for very high intensity measurements Al{sub 2}O{sub 3}:Cr screens are recommended.

Measurements of the Energy Deposition Profile for 238U Ions with Energy 500 and 950 MEV/U in Stainless Steel and Copper Targets

CERN Document Server

Mustafin, Edil; Gnutov, A; Golubev, Alexander; Hofmann, Ingo; Kantsyrev, Alexei; Kunin, Andrey; Latysheva, Ludmila N; Luckjashin, Victor; Panova, Yulia; Schardt, Dieter; Sobolevskiy, Nikolai; Vatulin, Vladimir; Weyrich, Karin

2005-01-01

Sub-millimeter wall thickness is foreseen for the vacuum tubes in the magnets of the superconducting dipoles of the SIS100 and SIS300 of the FAIR Project. The Bragg peak of the energy deposition by the U ions in these walls may lie dangerously close to the superconducting cables. Thus the precise knowledge of the dE/dx profile is essential for estimating the heat load by the lost ions in the vicinity of the superconducting wires. Here we present the results of the measurement of the U ion beam energy deposition profile in Cu and stainless steel targets and compare the measured data with the Monte-Carlo simulation using the SHIELD code.

Energy reflection coefficient for H+ ions at energies between 10 and 80 keV

International Nuclear Information System (INIS)

Chen, C.K.; Bohdansky, J.; Eckstein, W.; Robinson, M.T.

1984-04-01

The energy reflection coefficient for H + ions at energies between 10 keV and 80 keV was determined by experiments and by computer calculations. Measurements were made with graphite, Al, Cu, Mo and W. targets. The angle of ion incidence was restricted to 85 0 , 78 0 and 70 0 measured from the surface normal. Calculated data were obtained by two different Monte Carlo computer programs (MARLOWE, TRIM). It was found that both the calculated and the measured data scale with the parameter epsilon cos 2 α, where epsilon is Lindhard's reduced energy and α the angle of incidence for the ions. The measured values are smaller than those calculated. This can be explained by surface roughness which developed during the ion irradiation

Baseline measures for net-proton distributions in high energy heavy-ion collisions

International Nuclear Information System (INIS)

Netrakanti, P.K.; Mishra, D.K.; Mohanty, A.K.; Mohanty, B.

2014-01-01

The STAR experiment at the Relativistic Heavy-Ion Collider facility has reported results for the cumulants and their ratios from the net-proton distributions upto the fourth order cumulants at various collision energies. These measurements were carried to look for the signatures of the possible critical point (CP) in the phase diagram for a system undertaking strong interactions. The results show an intriguing dependence of the cumulant ratios C 3 /C 2 and C 4 /C 2 as a function of beam energy. The beam energy dependence appears to be non-monotonic in nature. However the experiment also reports that the energy dependence is observed to be consistent with expectation from an approach based on the independent production of proton and anti-protons in the collisions. In this paper we emphasize the need to have a proper baseline for appropriate interpretation of the cumulant measurements and argue that the comparison to independent production approach needs to be done with extreme caution

Scanning ion microscopy with low energy lithium ions

International Nuclear Information System (INIS)

Twedt, Kevin A.; Chen, Lei; McClelland, Jabez J.

2014-01-01

Using an ion source based on photoionization of laser-cooled lithium atoms, we have developed a scanning ion microscope with probe sizes of a few tens of nanometers and beam energies from 500 eV to 5 keV. These beam energies are much lower than the typical operating energies of the helium ion microscope or gallium focused ion beam systems. We demonstrate how low energy can be advantageous in ion microscopy when detecting backscattered ions, due to a decreased interaction volume and the potential for surface sensitive composition analysis. As an example application that demonstrates these advantages, we non-destructively image the removal of a thin residual resist layer during plasma etching in a nano-imprint lithography process. - Highlights: • We use an ion source based on photoionization of laser-cooled lithium atoms. • The ion source makes possible a low energy (500 eV to 5 keV) scanning ion microscope. • Low energy is preferred for ion microscopy with backscattered ions. • We use the microscope to image a thin resist used in nano-imprint lithography

Nuclear structure studies with low-energy light ions: fundamental and applied

International Nuclear Information System (INIS)

Mazumdar, I.

2016-01-01

Studies in low and medium energy nuclear physics have been dominated by heavy-ion induced reactions for last five decades. Heavy-ion induced nuclear reactions have enriched our knowledge of the structural evolutions and intricacies of reaction dynamics of the nuclear many-body systems. However, the emergence and rise of heavy-ion physics have seen a general decline in studies with low- and medium-energy light-ion beams. The harsh reality of dwindling number of low-energy light ion facilities adversely affect research in nuclear physics. Very low-energy and high current light-ion facilities immediately conjures up in our minds the studies in nuclear astrophysics. Measurements of light-ion capture cross sections and astrophysical S factors are the major themes of research at most of the light-ion facilities. However, the importance low energy light-ion beams is multifarious. A variety of measurements providing vital support and inputs to heavy-ion research can only be carried out at the low-energy, light-ion facilities. Light-ion beams are also useful for generation of mono-energetic neutron beams. In this talk I will draw from some of our recent measurements to show the importance of light-ion beams in nuclear astrophysics and also in applied nuclear physics. (author)

Energy straggling of heavy ions in solids

International Nuclear Information System (INIS)

Cowern, N.E.B.

1979-08-01

The energy-loss straggling of heavy ions has been studied, principally in the Born Approximation region v > zv 0 . Measurements were made with 5.486 MeV α particles, 5 - 48 MeV 16 0 ions, and 3 - 36 MeV 12 C ions, incident on thin uniform Al foils. The thickness uniformity of the foils was studied with a proton microbeam and a surface profiler, and their homogeneity, purity and isotropy were investigated by electron microscope, proton backscattering, and X-ray diffraction studies. Using the Bethe theory of energy loss the charge-exchange model of energy straggling for heavy ions is confirmed. (author)

Low energy ion-molecule reactions

Energy Technology Data Exchange (ETDEWEB)

Farrar, J.M. [Univ. of Rochester, NY (United States)

1993-12-01

This project is concerned with elucidating the dynamics of elementary ion-molecule reactions at collision energies near and below 1 eV. From measurements of the angular and energy distributions of the reaction products, one can infer intimathe details about the nature of collisions leading to chemical reaction, the geometries and lifetimes of intermediate complexes that govern the reaction dynamics, and the collision energy dependence of these dynamical features. The author employs crossed-beam low energy mass spectrometry technology developed over the last several years, with the focus of current research on proton transfer and hydrogen atom transfer reactions of te O{sup {minus}} ion with species such as HF, H{sub 2}O, and NH{sub 3}.

Ion energy distributions in bipolar pulsed-dc discharges of methane measured at the biased cathode

Energy Technology Data Exchange (ETDEWEB)

Corbella, C; Rubio-Roy, M; Bertran, E; Portal, S; Pascual, E; Polo, M C; Andujar, J L, E-mail: corbella@ub.edu [FEMAN Group, IN2UB, Departament de Fisica Aplicada i Optica, Universitat de Barcelona, c/ MartI i Franques 1, 08028 Barcelona (Spain)

2011-02-15

The ion fluxes and ion energy distributions (IED) corresponding to discharges in methane (CH{sub 4}) were measured in time-averaged mode with a compact retarding field energy analyser (RFEA). The RFEA was placed on a biased electrode at room temperature, which was powered by either radiofrequency (13.56 MHz) or asymmetric bipolar pulsed-dc (250 kHz) signals. The shape of the resulting IED showed the relevant populations of ions bombarding the cathode at discharge parameters typical in the material processing technology: working pressures ranging from 1 to 10 Pa and cathode bias voltages between 100 and 200 V. High-energy peaks in the IED were detected at low pressures, whereas low-energy populations became progressively dominant at higher pressures. This effect is attributed to the transition from collisionless to collisional regimes of the cathode sheath as the pressure increases. On the other hand, pulsed-dc plasmas showed broader IED than RF discharges. This fact is connected to the different working frequencies and the intense peak voltages (up to 450 V) driven by the pulsed power supply. This work improves our understanding in plasma processes at the cathode level, which are of crucial importance for the growth and processing of materials requiring controlled ion bombardment. Examples of industrial applications with these requirements are plasma cleaning, ion etching processes during fabrication of microelectronic devices and plasma-enhanced chemical vapour deposition of hard coatings (diamond-like carbon, carbides and nitrides).

Low-energy ion outflow modulated by the solar wind energy input

Science.gov (United States)

Li, Kun; Wei, Yong; Andre, Mats; Eriksson, Anders; Haaland, Stein; Kronberg, Elena; Nilsson, Hans; Maes, Lukas

2017-04-01

Due to the spacecraft charging issue, it has been difficult to measure low-energy ions of ionospheric origin in the magnetosphere. A recent study taking advantage of the spacecraft electric potential has found that the previously 'hidden' low-energy ions is dominant in the magnetosphere. This comprehensive dataset of low-energy ions allows us to study the relationship between the ionospheric outflow and energy input from the solar wind (ɛ). In this study, we discuss the ratios of the solar wind energy input to the energy of the ionospheric outflow. We show that the ɛ controls the ionospheric outflow when the ɛ is high, while the ionospheric outflow does not systematically change with the ɛ when the ɛ is low.

Energy spectrum of argon ions emitted from Filippov type Sahand plasma focus

International Nuclear Information System (INIS)

Mohammadnejad, M.; Pestehe, S. J.; Mohammadi, M. A.

2013-01-01

The energy and flux of the argon ions produced in Sahand plasma focus have been measured by employing a well-designed Faraday cup. The secondary electron emission effects on the ion signals are simulated and the dimensions of Faraday cup are optimized to minimize these effects. The measured ion energy spectrum is corrected for the ion energy loss and charge exchange in the background gas. The effects of the capacitor bank voltage and working gas pressure on the ion energy spectrum are also investigated. It has been shown that the emitted ion number per energy increases as the capacitor bank voltage increases. Decreasing the working gas pressure leads to the increase in the number of emitted ion per energy

Electrostatic ion cyclotron waves and ion energy diffusion in a mirror machine

International Nuclear Information System (INIS)

Turner, W.C.

1977-01-01

Measurements of ion cyclotron fluctuations and ion energy diffusion in the neutral beam injected 2XIIB mirror machine are presented. A narrow band single mode spectrum is always observed. When the plasma is de-stabilized by turning off axially injected streaming plasma, the wave amplitude increases and a simultaneous increase in ion-energy diffusion is observed. The spectral properties of the wave do not change. The data are in accord with a wave particle saturation of the drift cyclotron loss cone (DCLC) mode

Ion distribution dynamics near the Earth's bow shock: first measurements with the 2D ion energy spectrometer CORALL on the INTERBALL/Tail-probe satellite

Directory of Open Access Journals (Sweden)

Yu. I. Yermolaev

1997-05-01

Full Text Available The dynamics of the ion distribution function near the Earth's bow shock is studied on the basis of quasi-3D measurements of ion energy spectra in the range of 30–24200 eV/q with the Russian-Cuban CORALL instrument on the INTERBALL/Tail-probe satellite. The instrument was designed for observations of magnetospheric plasma and measures ions, in an angular range of 36°–144° from the Earth-Sun direction. Ion populations generated by the Earth bow shock are often observed upstream from the bow shock. In the solar-wind stream compressed and heated by the passing of very dense magnetic cloud (CME, two types of these ion populations were measured upstream and before the bow shock crossing on 25 August 1995 at 07:37 UT. Both populations were observed in the energy range above 2 keV. At ~06:20 UT, when the angle between the direction of the interplanetary magnetic field and normal to the bow shock VBn was ≃ 43° the instrument observed a narrow, fast (~800 km/s field-aligned beam moving from the Earth. At ~07:30, when Bn ≃ 28°, the wide ion pitch-angle distribution was observed. A similar suprathermal ion population is observed in the magnetosheath simultaneously with the solar-wind ion population being heated and deflected from the Sun-Earth direction. The similarity of observations during the mentioned time-interval and under usual solar-wind conditions allows us to conclude that types of suprathermal ion populations upstream and downstream from the bow shock do not depend on the solar-wind disturbance generated by magnetic cloud.

Linac4 low energy beam measurements with negative hydrogen ions

Energy Technology Data Exchange (ETDEWEB)

Scrivens, R., E-mail: richard.scrivens@cern.ch; Bellodi, G.; Crettiez, O.; Dimov, V.; Gerard, D.; Granemann Souza, E.; Guida, R.; Hansen, J.; Lallement, J.-B.; Lettry, J.; Lombardi, A.; Midttun, Ø.; Pasquino, C.; Raich, U.; Riffaud, B.; Roncarolo, F.; Valerio-Lizarraga, C. A.; Wallner, J.; Yarmohammadi Satri, M.; Zickler, T. [CERN, 1211 Geneva 23 (Switzerland)

2014-02-15

Linac4, a 160 MeV normal-conducting H{sup −} linear accelerator, is the first step in the upgrade of the beam intensity available from the LHC proton injectors at CERN. The Linac4 Low Energy Beam Transport (LEBT) line from the pulsed 2 MHz RF driven ion source, to the 352 MHz RFQ (Radiofrequency Quadrupole) has been built and installed at a test stand, and has been used to transport and match to the RFQ a pulsed 14 mA H{sup −} beam at 45 keV. A temporary slit-and-grid emittance measurement system has been put in place to characterize the beam delivered to the RFQ. In this paper a description of the LEBT and its beam diagnostics is given, and the results of beam emittance measurements and beam transmission measurements through the RFQ are compared with the expectation from simulations.

Relationship between wave energy and free energy from pickup ions in the Comet Halley environment

Science.gov (United States)

Huddleston, D. E.; Johnstone, A. D.

1992-01-01

The free energy available from the implanted heavy ion population at Comet Halley is calculated by assuming that the initial unstable velocity space ring distribution of the ions evolves toward a bispherical shell. Ultimately this free energy adds to the turbulence in the solar wind. Upstream and downstream free energies are obtained separately for the conditions observed along the Giotto spacecraft trajectory. The results indicate that the waves are mostly upstream propagating in the solar wind frame. The total free energy density always exceeds the measured wave energy density because, as expected in the nonlinear process of ion scattering, the available energy is not all immediately released. An estimate of the amount which has been released can be obtained from the measured oxygen ion distributions and again it exceeds that observed. The theoretical analysis is extended to calculate the k spectrum of the cometary-ion-generated turbulence.

Surface potential measurement of negative-ion-implanted insulators by analysing secondary electron energy distribution

International Nuclear Information System (INIS)

Toyota, Yoshitaka; Tsuji, Hiroshi; Nagumo, Syoji; Gotoh, Yasuhito; Ishikawa, Junzo; Sakai, Shigeki.

1994-01-01

The negative ion implantation method we have proposed is a noble technique which can reduce surface charging of isolated electrodes by a large margin. In this paper, the way to specify the surface potential of negative-ion-implanted insulators by the secondary electron energy analysis is described. The secondary electron energy distribution is obtained by a retarding field type energy analyzer. The result shows that the surface potential of fused quartz by negative-ion implantation (C - with the energy of 10 keV to 40 keV) is negatively charged by only several volts. This surface potential is extremely low compared with that by positive-ion implantation. Therefore, the negative-ion implantation is a very effective method for charge-up free implantation without charge compensation. (author)

A high-energy electron beam ion trap for production of high-charge high-Z ions

International Nuclear Information System (INIS)

Knapp, D.A.; Marrs, R.E.; Elliott, S.R.; Magee, E.W.; Zasadzinski, R.

1993-01-01

We have developed a new high-energy electron beam ion trap, the first laboratory source of low-energy, few-electron, high-Z ions. We describe the device and report measurements of its performance, including the electron beam diameter, current density and energy, and measurements of the ionization balance for several high-Z elements in the trap. This device opens up a wide range of possible experiments in atomic physics, plasma physics, and nuclear physics. (orig.)

Electron capture by multicharged ions at eV energies

International Nuclear Information System (INIS)

Havener, C.C.; Huq, M.S.; Meyer, F.W.; Phaneuf, R.A.

1988-01-01

A multicharged ion-atom merged-beams apparatus has been used in conjunction with the ORNL-ECR ion source to measure accurate absolute electron-capture cross sections in the energy range from below 1 eV/amu to 1500 eV/amu. Measurements for N/sup 3+,4+,5+/ /plus/ H(D) collisions indicate good agreement with available theoretical calculations. However, measurements with O 5+ /plus/ H(D) show an unexpected low-energy behavior which may be attributable to the ion-induced-dipole attraction between the reactants. Scaled Landau-Zener calculations presented here identify a transfer plus excitation channel which has the correct energy dependence at low energies. This finding suggest the need for a comprehensive coupled channel calculation which would include such product states. 25 refs., 8 figs

High Energy Ion Acceleration by Extreme Laser Radiation Pressure

Science.gov (United States)

2017-03-14

published in the internationally leading journal Physical Review Letters. We continued to progress this pionee 15.  SUBJECT TERMS ion therapy, heavy ion ...Thomson parabola spectrometer: To separate and provide a measurement of the charge -to-mass ratio and energy spectrum of the different ion species...AFRL-AFOSR-UK-TR-2017-0015 High energy ion acceleration by extreme laser radiation pressure Paul McKenna UNIVERSITY OF STRATHCLYDE VIZ ROYAL COLLEGE

Computer-controlled system for plasma ion energy auto-analyzer

International Nuclear Information System (INIS)

Wu Xianqiu; Chen Junfang; Jiang Zhenmei; Zhong Qinghua; Xiong Yuying; Wu Kaihua

2003-01-01

A computer-controlled system for plasma ion energy auto-analyzer was technically studied for rapid and online measurement of plasma ion energy distribution. The system intelligently controls all the equipments via a RS-232 port, a printer port and a home-built circuit. The software designed by LabVIEW G language automatically fulfils all of the tasks such as system initializing, adjustment of scanning-voltage, measurement of weak-current, data processing, graphic export, etc. By using the system, a few minutes are taken to acquire the whole ion energy distribution, which rapidly provide important parameters of plasma process techniques based on semiconductor devices and microelectronics

Low energy implantation of boron with decaborane ions

Science.gov (United States)

Albano, Maria Angela

The goal of this dissertation was to determine the feasibility of a novel approach to forming ultra shallow p-type junctions (tens of nm) needed for future generations of Si MOS devices. In the new approach, B dopant atoms are implanted by cluster ions obtained by ionization of decaborane (B 10H14) vapor. An experimental ion implanter with an electron impact ion source and magnetic mass separation was built at the Ion Beam and Thin Film Research Laboratory at NJIT. Beams of B10Hx+ ions with currents of a few microamperes and energies of 1 to 12 keV were obtained and used for implantation experiments. Profiles of B and H atoms implanted in Si were measured by Secondary Ion Mass Spectroscopy (SIMS) before and after rapid thermal annealing (RTA). From the profiles, the junction depth of 57 nm (at 1018 cm-3 B concentration) was obtained with 12 keV decaborane ions followed by RTA. The dose of B atoms that can be implanted at low energy into Si is limited by sputtering as the ion beam sputters both the matrix and the implanted atoms. As the number of sputtered B atoms increases with the implanted dose and approaches the number of the implanted atoms, equilibrium of B in Si is established. This effect was investigated by comparison of the B dose calculated from the ion beam integration with B content in the sample measured by Nuclear Reaction Analysis (NRA). Maximum (equilibrium) doses of 1.35 x 1016 B cm -2 and 2.67 x 1016 B cm-2 were obtained at the beam energies of 5 and 12 keV, respectively. The problem of forming shallow p-type junctions in Si is related not only to implantation depth, but also to transient enhanced diffusion (TED). TED in Si implanted with B10Hx+ was measured on boron doping superlattice (B-DSL) marker layers. It was found that TED, following decaborane implantation, is the same as with monomer B+ ion implantation of equivalent energy and that it decreases with the decreasing ion energy. (Abstract shortened by UMI.)

Enhancements to the Low-Energy Ion Facility at SUNY Geneseo

Science.gov (United States)

Barfield, Zachariah; Kostick, Steven; Nagasing, Ethan; Fletcher, Kurt; Padalino, Stephen

2017-10-01

The Low Energy Ion Facility at SUNY Geneseo is used for detector development and characterization for inertial confinement fusion diagnostics. The system has been upgraded to improve the ion beam quality by reducing contaminant ions. In the new configuration, ions produced by the Peabody Scientific duoplasmatron ion source are accelerated through a potential, focused into a new NEC analyzing magnet and directed to an angle of 30°. A new einzel lens on the output of the magnet chamber focuses the beam into a scattering chamber with a water-cooled target mount and rotatable detector mount plates. The analyzing magnet has been calibrated for deuteron, 4He+, and 4He2+ ion beams at a range of energies, and no significant hysteresis has been observed. The system can accelerate deuterons to energies up to 25 keV to initiate d-d fusion using a deuterated polymer target. Charged particle spectra with protons, tritons, and 3He ions from d-d fusion have been measured at scattering angles ranging from 55° to 135°. A time-of-flight beamline has been designed to measure the energies of ions elastically scattered at 135°. CEM detectors initiate start and stop signals from secondary electrons produced when low energy ions pass through very thin carbon foils. Funded in part by the U.S. Department of Energy through the Laboratory for Laser Energetics.

Space- and time-resolved measurements of ion energy distributions by neutral beam injection in TORTUR II

International Nuclear Information System (INIS)

Brocken, H.J.B.M.

1981-10-01

A method is described for the space- and time-resolved analysis of ion energy distributions in a plasma. A well-collimated neutral hydrogen beam is used to enhance the charge-exchange processes. The method is used in the TORTUR II tokamak to study the space and time evolution of the ion temperature profile of the plasma. The analytical background and the technique are described in detail. Examples of measurements on TORTUR II are presented

Analysis of retarding field energy analyzer transmission by simulation of ion trajectories

Science.gov (United States)

van de Ven, T. H. M.; de Meijere, C. A.; van der Horst, R. M.; van Kampen, M.; Banine, V. Y.; Beckers, J.

2018-04-01

Retarding field energy analyzers (RFEAs) are used routinely for the measurement of ion energy distribution functions. By contrast, their ability to measure ion flux densities has been considered unreliable because of lack of knowledge about the effective transmission of the RFEA grids. In this work, we simulate the ion trajectories through a three-gridded RFEA using the simulation software SIMION. Using idealized test cases, it is shown that at high ion energy (i.e., >100 eV) the transmission is equal to the optical transmission rather than the product of the individual grid transparencies. Below 20 eV, ion trajectories are strongly influenced by the electric fields in between the grids. In this region, grid alignment and ion focusing effects contribute to fluctuations in transmission with ion energy. Subsequently the model has been used to simulate the transmission and energy resolution of an experimental RFEA probe. Grid misalignments reduce the transmission fluctuations at low energy. The model predicts the minimum energy resolution, which has been confirmed experimentally by irradiating the probe with a beam of ions with a small energy bandwidth.

Measurement of line overlap for resonant photopumping of transitions in neonlike ions by nickel-like ions

International Nuclear Information System (INIS)

Elliott, S.; Beiersdorfer, P.; Nilsen, J.

1993-01-01

A measurement is made of the 3d-4f transition energies in the Ni-like ions Re 47+ , Ir 49+ , Pt 50+ , Au 51+ , and Bi 55+ and the 2p-4d transition energies in the Ne-like ions Br 25+ , Kr 26+ , Rb 27+ , and Y 29+ using the Livermore electron-beam ion trap. The ions studied are candidates for an x-ray laser scheme based on resonant photopumping which predicts lasing among the 3p-3s transitions in a Ne-like ion. The results of the measurements are compared to multiconfiguration Dirac-Fock calculations and systematic differences are found. The best resonance is found for the Pt-Rb pair at 2512 eV, whose energies differ by 0.4±0.1 eV, that is, by only 160 ppm

Low energy ion beam dynamics of NANOGAN ECR ion source

Energy Technology Data Exchange (ETDEWEB)

Kumar, Sarvesh, E-mail: sarvesh@iuac.res.in; Mandal, A.

2016-04-01

A new low energy ion beam facility (LEIBF) has been developed for providing the mass analyzed highly charged intense ion beams of energy ranging from a few tens of keV to a few MeV for atomic, molecular and materials sciences research. The new facility consists of an all permanent magnet 10 GHz electron cyclotron resonance (ECR) ion source (NANOGAN) installed on a high voltage platform (400 kV) which provides large currents of multiply charged ion beams. Higher emittance at low energy of intense ion beam puts a tremendous challenge to the beam optical design of this facility. The beam line consists of mainly the electrostatic quadrupoles, an accelerating section, analyzing cum switching magnet and suitable beam diagnostics including vacuum components. The accelerated ion beam is analyzed for a particular mass to charge (m/q) ratio as well as guided to three different lines along 75°, 90° and 105° using a large acceptance analyzing cum switching magnet. The details of transverse beam optics to all the beam lines with TRANSPORT and GICOSY beam optics codes are being described. Field computation code, OPERA 3D has been utilized to design the magnets and electrostatic quadrupoles. A theoretical estimation of emittance for optimized geometry of ion source is given so as to form the basis of beam optics calculations. The method of quadrupole scan of the beam is used to characterize the emittance of the final beam on the target. The measured beam emittance increases with m/q ratios of various ion beams similar to the trend observed theoretically.

Low-energy hydrogen flux measurements at the TORTUR tokamak with negative ion conversion

International Nuclear Information System (INIS)

Toledo, Wiebo van.

1990-01-01

The interaction of a tokamak plasma with the vessel wall is one of the most important subjects in thermonuclear research. The information about this interaction is not complete without direct detection of the outward stream of low-energy, down to a few electronvolts, neutral hydrogen or deuterium atoms. The detection of these atoms is the subject of this thesis. An appropriate method to analyse the atoms which are emitted from the edge plasma is to use a time-of-flight analyser. This kind of apparatus selects particles according to their velocities with-out distinguishing between different masses. If these analysers use the Daly-method the lowest measurable energy of the hydrogen atoms is approximately 25 electronvolts. To increase the detection efficiency a new detection method was developed. This new method uses the conversion of hydrogen atoms into H- ions on a cesiated tungsten surface. By this conversion the lowest measurable energy is decreased down to 5 electron-volt. (author). 93 refs.; 44 figs.; 7 tabs

Measurements of the Properties of Highly-charged high-Z ions

International Nuclear Information System (INIS)

Augustine J. Smith, Ph.D.

2007-01-01

We had proposed carrying out a systematic experimental investigation of the atomic physics of highly charged, high-Z ions, produced in the Lawrence Livermore National Laboratory LLNL electron beam ion trap (EBIT-I) in its high energy mode, superEBIT. In particular we were going to accurately measure line positions for Δn=0 transitions in few electron high-Z ions; this was meant to enable us to investigate relativistic and quantum electrodynamics QED contributions to the energy levels as well as the nuclear properties of heavy ions. We were also going to measure cross sections for various electron-ion interactions, the degree of polarization of emitted x-rays, and radiation cooling rates of various ionization stages of highly charged, high-Z ions. This would enable us to study fundamental atomic physics of high-Z ions at relativistic electron impact energies and in the intense nuclear fields of highly ionized, high-Z ions. This would extend previous measurements we have carried out to a regime where there is a paucity of good data. These measurements were expected to generate increased theoretical interest and activity in this area. The project will extend a very successful collaboration between Morehouse College (MC) and a national laboratory LLNL, Minority student training and development are major components of the proposal

Ion energy and angular distributions in inductively coupled Argon RF discharges

International Nuclear Information System (INIS)

Woodworth, J.R.; Riley, M.E.; Meister, D.C.

1996-03-01

We report measurements of the energies and angular distributions of positive ions in an inductively coupled argon plasma in a GEC reference cell. Use of two separate ion detectors allowed measurement of ion energies and fluxes as a function of position as well as ion angular distributions on the discharge centerline. The inductive drive on our system produced high plasma densities (up to 10 12 /cm 3 electron densities) and relatively stable plasma potentials. As a result, ion energy distributions typically consisted of a single feature well separated from zero energy. Mean ion energy was independent of rf power and varied inversely with pressure, decreasing from 29 eV to 12 eV as pressure increased form 2.4 m Torr to 50 mTorr. Half-widths of the ion angular distributions in these experiments varied from 5 degrees to 12.5 degrees, or equivalently, transverse temperatures varied form 0.2 to 0.5 eV with the distributions broadening as either pressure or RF power were increased

Low energy ion implantation and high energy heavy ion irradiation in C60 films

International Nuclear Information System (INIS)

Narayanan, K.L.; Yamaguchi, M.; Dharmarasu, N.; Kojima, N.; Kanjilal, D.

2001-01-01

C 60 films have been bombarded with low energy boron ions and high energy swift heavy ions (SHI) of silver and oxygen at different doses. Raman scattering and Fourier transform infrared (FTIR) studies were carried out on the virgin and irradiated films and the results are in good agreement with each other. The films subject to low energy boron ion implantation showed destruction of the bukky balls whereas the films subject to high energy ion irradiation did not show appreciable effects on their structure. These results indicate that C 60 films are more prone to defects by elastic collision and subsequent implantation at lower energy. Irradiation at higher energy was less effective in creating appreciable defects through electronic excitation by inelastic collisions at similar energy density

Fragmentation and reactivity of energy-selected ferrocenium ions

International Nuclear Information System (INIS)

Mestdagh, H.; Dutuit, O.; Heninger, M.; Thissen, R.; Alcaraz, C.

2002-01-01

In this study, results concerning the discussion of state-selected ferrocenium ions (c-C 5 H 5 ) 2 Fe + commonly called Cp 2 Fe + , as well as their reactions with methanol and ethanol are presented. Parent ions Cp 2 Fe + were produced by vacuumultraviolett (VUV) photoionization of neutral ferrocene using synchrotron radiation, and selected in internal energy by threshold photoelectron-photoion coincidences. The apparatus is divided into three differentially pumped regions: the source, the reaction and the detection zones. In source, state-selected parent ions are formed and can be selected in mass by a first quadrupole filter. State-selected ions are then injected in the second zone which is a RF octopole ion guide where reaction product ions are mass analyzed by a second quadrupole filter and detected by microchannelplates. In addition, the long flight time in the octopoles (several hundreds of microseconds) allows studying long-lived metastable ions. Total mass spectra were recorded at different photon energies, in addition to the main CpFe + and Fe + fragments, several minor fragments were detected such as C 10 H 10 + which reflects the formation of a C-C bond between the two Cp ligands. Losses of CH 3 , C 2 H 2 and C-4H 4 also indicate that important structure rearrangements take place before cleavage. The appearance energies of each mass-selected fragment ion were measured by recording fragment ion yields as a function of photon energy. Surprisingly, all fragments were found to have the same energy onset, i.e. 13.2 eV photon energy, except for C 3 H 3 Fe + (m/z 95). For Fe + ions, a sharp increase was observed at 17 eV, above the thermochemical onset of Fe + + 2 Cp. The 13.2 eV appearance energy of Fe + is thus assigned to the formation of Fe - + C 10 H 10 . The reactivity of ferrocenium ion with methanol and ethanol was investigated as a function of photon energy. While no reaction occurs at lower photon energies, several reaction products appear at 13.0 e

Production of low axial energy spread ion beams with multicusp sources

Energy Technology Data Exchange (ETDEWEB)

Lee, Yung -Hee Y. [Univ. of California, Berkeley, CA (United States)

1998-05-01

Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as: ion projection lithography (IPL) and focused ion beams for the next generation lithographic tools and nuclear science experiments such as radioactive ion beam production. The axial ion energy spread for multicusp source is approximately 6 eV which is too large for IPL and radioactive ion beam applications. The addition of a magnetic filter which consists of a pair of permanent magnets to the multicusp source reduces the energy spread considerably. The reduction is due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. Axial ion energy spread of the filament driven ion source has been measured using three different techniques. In all cases, it was found to be less than 2 eV. Energy spread of the radio frequency (RF) driven source has also been explored, and it was found to be less than 3 eV with the proper RF-shielding. A new multicusp source configuration has been designed and constructed to further reduce the energy spread. To achieve a more uniform axial plasma potential distribution, a cylindrical magnetic filter has been designed and constructed for a 2-cm-diameter source. This new source configuration, the co-axial source, is new in its kind. The energy spread in this source has been measured to be a record low of 0.6 eV. Because of the novelty of this device, some plasma parameters inside the source have been studied. Langmuir probe has been used to measure the plasma potential, the electron temperature and the density distribution.

Production of low axial energy spread ion beams with multicusp sources

International Nuclear Information System (INIS)

Lee, Y.H.Y.

1998-05-01

Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as: ion projection lithography (IPL) and focused ion beams for the next generation lithographic tools and nuclear science experiments such as radioactive ion beam production. The axial ion energy spread for multicusp source is approximately 6 eV which is too large for IPL and radioactive ion beam applications. The addition of a magnetic filter which consists of a pair of permanent magnets to the multicusp source reduces the energy spread considerably. The reduction is due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. Axial ion energy spread of the filament driven ion source has been measured using three different techniques. In all cases, it was found to be less than 2 eV. Energy spread of the radio frequency (RF) driven source has also been explored, and it was found to be less than 3 eV with the proper RF-shielding. A new multicusp source configuration has been designed and constructed to further reduce the energy spread. To achieve a more uniform axial plasma potential distribution, a cylindrical magnetic filter has been designed and constructed for a 2-cm-diameter source. This new source configuration, the co-axial source, is new in its kind. The energy spread in this source has been measured to be a record low of 0.6 eV. Because of the novelty of this device, some plasma parameters inside the source have been studied. Langmuir probe has been used to measure the plasma potential, the electron temperature and the density distribution

High-resolution measurements of x rays from ion-atom collisions

International Nuclear Information System (INIS)

Knudson, A.R.

1974-01-01

High resolution measurements of K x-ray spectra produced by ion-atom collisions at MeV energies are presented. These measurements indicate that a distribution of L-shell vacancies accompanies K-shell excitation. The variation of these spectra as a function of incident ion energy and atomic number is discussed. Difficulties in the analysis of these spectra due to rearrangement of vacancies between the time of the collision and the time of x-ray emission are considered. The use of high resolution x-ray measurements to obtain information on projectile ion vacancy configurations is demonstrated by data for Ar ions in KCl. X-ray spectra from Al projectiles in a variety of targets were measured and the effect of target composition on these spectra is discussed

Energy and Pitch Distribution of Spontaneously-generated High-energy Bulk Ions in the RFP

Science.gov (United States)

Kim, Jungha; Anderson, Jay; Reusch, Joshua; Eilerman, Scott; Capecchi, William

2014-10-01

Magnetic reconnection events in the reversed field pinch (RFP) are known to heat bulk and impurity ions. Runaway due to a parallel electric field has recently been confirmed as an important acceleration mechanism for high energy test ions supplied by a neutral beam. This effect does not, however, explain the change in distribution of nearly Maxwellian bulk ions at a reconnection event. By operating MST near maximum current and low electron density, significant fusion neutron flux can be generated without neutral beam injection. The bulk ion distribution created in these plasmas is well-confined, non-Maxwellian, and can be measured by the Advanced Neutral Particle Analyzer (ANPA) placed at a radial or tangential porthole. Data show a high energy tail up to 25 keV with a relatively higher signal in the low energy channels (8-15 keV) at the radial port following a reconnection event. Analysis of the energy dependence of trapped orbits sampled by the ANPA at the radial view implies an abundance of lower energy particles in regions of higher neutral density. This mandates a careful deconvolution of the measured ANPA signal to compute the fast ion distribution. This work is supported by the US DOE and NSF.

Energy loss and straggling of MeV ions through biological samples

International Nuclear Information System (INIS)

Ma Lei; Wang Yugang; Xue Jianming; Chen Qizhong; Zhang Weiming; Zhang Yanwen

2007-01-01

Energy loss and energy straggling of energetic ions through natural dehydrated biological samples were investigated using transmission technique. Biological samples (onion membrane, egg coat, and tomato coat) with different mass thickness were studied, together with Mylar for comparison. The energy loss and energy straggling of MeV H and He ions after penetrating the biological and Mylar samples were measured. The experimental results show that the average energy losses of MeV ions through the biological samples are consistent with SRIM predictions; however, large deviation in energy straggling is observed between the measured results and the SRIM predictions. Taking into account inhomogeneity in mass density and structure of the biological sample, an energy straggling formula is suggested, and the experimental energy straggling values are well predicted by the proposed formula

ECR ion source based low energy ion beam facility

Indian Academy of Sciences (India)

Mass analyzed highly charged ion beams of energy ranging from a few keV to a few MeV plays an important role in various aspects of research in modern physics. In this paper a unique low energy ion beam facility (LEIBF) set up at Nuclear Science Centre (NSC) for providing low and medium energy multiply charged ion ...

Mechanism of long-range penetration of low-energy ions in botanic samples

International Nuclear Information System (INIS)

Liu Feng; Wang Yugang; Xue Jianming; Wang Sixue; Du Guanghua; Yan Sha; Zhao Weijiang

2002-01-01

The authors present experimental evidence to reveal the mechanism of long-range penetration of low-energy ions in botanic samples. In the 100 keV Ar + ion transmission measurement, the result confirmed that low-energy ions could penetrate at least 60 μm thick kidney bean slices with the probability of about 1.0 x 10 -5 . The energy spectrum of 1 MeV He + ions penetrating botanic samples has shown that there is a peak of the count of ions with little energy loss. The probability of the low-energy ions penetrating the botanic sample is almost the same as that of the high-energy ions penetrating the same samples with little energy loss. The results indicate that there are some micro-regions with mass thickness less than the projectile range of low-energy ions in the botanic samples and they result in the long-range penetration of low-energy ions in botanic samples

New approach to energy loss measurements

CERN Document Server

Trzaska, W H; Alanko, T; Mutterer, M; Raeisaenen, J; Tjurin, G; Wojdyr, M

2002-01-01

A new approach to energy loss measurements is proposed. In the same experiment electronic stopping force (power) in gold, nickel, carbon, polycarbonate and Havar for sup 4 sup 0 Ar, sup 2 sup 8 Si, sup 1 sup 6 O, sup 4 He and sup 1 H ions in the energy range 0.12-11 MeV/u has been measured. In this paper we give the full results for gold, nickel, and carbon and for sup 4 sup 0 Ar, sup 1 sup 6 O, sup 4 He and sup 1 H ions. Good agreement of the measured stopping force values for light ions with literature data is interpreted as the positive test of the experimental technique. The same technique used with heavy ions yields agreement with the published data only for energies above 1 MeV/u. At lower energies we observe progressively increasing discrepancy. This discrepancy is removed completely as soon as we neglect pulse height defect compensation. This observation makes us believe that the majority of the published results as well as semi-empirical calculations based on them (like the popular SRIM) may be in er...

Electron-ion recombination at low energy

International Nuclear Information System (INIS)

Andersen, L.H.

1993-01-01

The work is based on results obtained with a merged-beams experiment. A beam of electronics with a well characterized density and energy distribution was merged with a fast, monoenergetic ion beam. Results have been obtained for radiative recombination and dielectronic recombination at low relative energies (0 to ∼70eV). The obtained energy resolution was improved by about a factor of 30. High vacuum technology was used to suppress interactions with electrons from the environments. The velocity distribution of the electron beam was determined. State-selective dielectronic-recombination measurements were performable. Recombination processes were studied. The theoretical background for radiative recombination and Kramers' theory are reviewed. The quantum mechanical result and its relation to the semiclassical theory is discussed. Radiative recombination was also measured with several different non-bare ions, and the applicability of the semiclassical theory to non-bare ions was investigated. The use of an effective charge is discussed. For dielectronic recombination, the standard theoretical approach in the isolated resonance and independent-processes approximation is debated. The applicability of this method was tested. The theory was able to reproduce most of the experimental data except when the recombination process was sensitive to couplings between different electronic configurations. The influence of external perturbing electrostatic fields is discussed. (AB) (31 refs.)

Spectroscopic measurement of ion temperature and ion velocity distributions in the flux-coil generated FRC

International Nuclear Information System (INIS)

Gupta, D.; Gota, H.; Hayashi, R.; Kiyashko, V.; Morehouse, M.; Primavera, S.; Bolte, N.; Marsili, P.; Roche, T.; Wessel, F.

2010-01-01

One aim of the flux-coil generated field reversed configuration at Tri Alpha Energy (TAE) is to establish the plasma where the ion rotational energy is greater than the ion thermal energy. To verify this, an optical diagnostic was developed to simultaneously measure the Doppler velocity-shift and line-broadening using a 0.75 m, 1800 groves/mm, spectrometer. The output spectrum is magnified and imaged onto a 16-channel photomultiplier tube (PMT) array. The individual PMT outputs are coupled to high-gain, high-frequency, transimpedance amplifiers, providing fast-time response. The Doppler spectroscopy measurements, along with a survey spectrometer and photodiode-light detector, form a suite of diagnostics that provide insights into the time evolution of the plasma-ion distribution and current when accelerated by an azimuthal-electric field.

Scrape-off layer ion temperature measurements at the divertor target during type III ELMs in MAST measured by RFEA

Energy Technology Data Exchange (ETDEWEB)

Elmore, S., E-mail: Sarah.Elmore@ccfe.ac.uk [CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Allan, S.Y.; Fishpool, G.; Kirk, A. [CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Kočan, M. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Tamain, P. [Association Euratom-CEA, CEA/DSM/IRFM, CEA-Cadarache, F-13108 St Paul-lez-Durance Cedex (France); Thornton, A.J. [CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

2015-08-15

Edge-localised modes (ELMs) can carry significant fractions of their energy as far as main chamber plasma-facing components in divertor tokamaks. Since in future devices (e.g. ITER, DEMO) these energies could cause issues for material lifetime and impurity production, the energy and temperature of ions in ELMs needs to be investigated. In MAST, novel divertor measurements of T{sub i} during ELMs have been made using the divertor retarding field energy analyser (RFEA) probe. These measurements have shown instantaneous ion energy distributions corresponding to an effective T{sub i} at 5 cm from the strike point at the target that can be as high as 60 eV and that this decreases with time after the ELM start. This is consistent with the hottest, fastest ions arriving at the target first by parallel transport, followed by the lower end of the ion energy distribution. This analysis will form a basis for future data analysis of fast swept measurements of ion distributions in ELMs.

Measurements of isomers at the FRS ion catcher

Energy Technology Data Exchange (ETDEWEB)

Hornung, Christine [Justus-Liebig Universitaet Giessen (Germany); Collaboration: FRS Ion Catcher-Collaboration

2016-07-01

Projectile fragmentation and fission reactions at in-flight facilities are important production mechanisms to access short-lived exotic nuclei. It is a challenge to describe the angular momentum distribution after the collision of relativistic nuclei. This can be experimentally accessed by measuring the population of isomeric states. Isomeric ratios and excitation energies of isomers of short-lived exotic nuclei can be determined at the FRS Ion Catcher at GSI. At the FRS, projectile and fission fragments are produced at relativistic energies, separated in-flight and range-focused. They are slowed down and thermalized in a cryogenic stopping cell. In a multi-purpose RFQ beamline alpha spectroscopy can be performed. Alternatively the ions can be transported to a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS), where masses of the ground and isomeric states can be measured simultaneously with high resolving power. The MR-TOF-MS can also be used to spatially separate the ions in order to provide isomerically clean ion beams. During a recent experiment isomer-to-ground state ratios and excitation energies of uranium projectile and fission fragments produced at 1 GeV/u were measured. The ratios, measured with the MR-TOF-MS, were verified by alpha spectroscopy. Furthermore the ratios were compared to calculations based on an abrasion-ablation model of fragmentation.

Transmitted ion energy loss distributions to detect cluster formation in silicon

International Nuclear Information System (INIS)

Selen, L.J.M.; Loon, A. van; IJzendoorn, L.J. van; Voigt, M.J.A. de

2002-01-01

The energy loss distribution of ions transmitted through a 5.7±0.2 μm thick Si crystal was measured and simulated with the Monte Carlo channeling simulation code FLUX. A general resemblance between the measured and simulated energy loss distributions was obtained after incorporation of an energy dependent energy loss in the simulation program. The energy loss calculations are used to investigate the feasibility to detect the presence of light element dopant clusters in a host crystal from the shape of the energy loss distribution, with transmission ion channeling. A curved crystal structure is used as a model for a region in the host crystal with clusters. The presence of the curvature does have a large influence on the transmitted energy distribution, which offers the possibility to determine the presence of dopant clusters in a host crystal with transmission ion channeling

Ion-ion interaction and energy transfer of 4+ transuranium ions in cerium tetrafluoride

International Nuclear Information System (INIS)

Liu, G.K.; Beitz, J.V.

1990-01-01

Dynamics of excited 5f electron states of the transuranium ions Cm 4+ and Bk 4+ in CeF 4 are compared. Based on time- and wavelength-resolved laser-induced fluorescence, excitation energy transfer processes have been probed. Depending on concentration and electronic energy level structure of the studied 4+ transuranium ion, the dominant energy transfer mechanisms were identified as cross relaxation, exciton-exciton annihilation, and trapping. Energy transfer rates derived from the fitting of the observed fluorescence decays to theoretical models, based on electric multipolar ion-ion interactions, are contrasted with prior studies of 4f states of 3+ lanthanide and 3d states of transition metal ions. 16 refs., 1 tab

Channeling effect for low energy ion implantation in Si

International Nuclear Information System (INIS)

Cho, K.; Allen, W.R.; Finstad, T.G.; Chu, W.K.; Liu, J.; Wortman, J.J.

1985-01-01

Ion implantation is one of the most important processes in semiconductor device fabrication. Due to the crystalline nature of Si, channeling of implanted ions occurs during this process. Modern devices become smaller and shallower and therefore require ion implantation at lower energies. The effect of channeling on ion implantation becomes a significant problem for low energy ion implantation. The critical angle for axial and planar channeling increases with decreasing energy. This corresponds to an increased probability for channeling with lowering of ion energy. The industry approach to avoid the channeling problem is to employ a tilt angle of 7 0 between the ion implantation direction and the surface normal. We approach the problem by mapping major crystalline axes and planes near the [100] surface normal. Our analysis indicates that a 7 0 tilt is not an optimum selection in channeling reduction. Tilt angles in the range 5 0 to 6 0 combined with 7 0 +- 0.5 0 rotation from the (100) plane are better selections for the reduction of the channeling effect. The range of suitable angles is a function of the implantation energy. Implantations of boron along well specified crystallographic directions have been carried out by careful alignment and the resulting boron profiles measured by SIMS. (orig.)

Atomic physics measurements in an electron Beam Ion Trap

International Nuclear Information System (INIS)

Marrs, R.E.; Beiersdorfer, P.; Bennett, C.

1989-01-01

An electron Beam Ion Trap at Lawrence Livermore National Laboratory is being used to produce and trap very-highly-charged ions (q ≤ 70/+/) for x-ray spectroscopy measurements. Recent measurements of transition energies and electron excitation cross sections for x-ray line emission are summarized. 13 refs., 10 figs

Measurements of Ion Stopping around the Bragg Peak in High-Energy-Density Plasmas

Science.gov (United States)

Frenje, Johan

2015-11-01

Over the last few decades, ion stopping in weakly- to strongly-coupled High-Energy-Density (HED) plasmas has been subject to extensive analytical and numerical studies, but only a limited set of experimental data exists to check the validity of these theories. Most of these experiments also did not probe the detailed characteristics of the Bragg peak (peak ion stopping) where the ion velocity is similar to the average thermal electron velocity. To the best of our knowledge, only one exploratory attempt to do this was conducted by Hicks et al., who were able to describe qualitatively the behavior of the Bragg peak for one plasma condition. The work described in this presentation makes significant advances over previous experimental efforts by quantitatively assessing the characteristics of the ion stopping, ranging from low-velocity stopping, through the Bragg peak, to high-velocity stopping for different HED plasma conditions. This was achieved by measuring the energy loss of DD-tritons, D3He-alphas, DD-protons and D3He-protons, with distinctly different velocities, and the results indicate that the stopping power varies strongly with Te and ne. This effort represents the first experimental test of state-of-art plasma-stopping-power theories around the Bragg peak, which is an important first step in our efforts of getting a fundamental understanding of DT-alpha stopping in HED plasmas, a prerequisite for understanding ignition margins in various implosion designs with varying hot spot areal density at the National Ignition Facility. The work described here was performed in part at the LLE National Laser User's Facility (NLUF), and was supported in part by US DOE (Grant No. DE-FG03- 03SF22691), LLNL (subcontract Grant No. B504974) and LLE (subcontract Grant No. 412160-001G).

Measurements of actinometry and ions energy in a microwave discharge

International Nuclear Information System (INIS)

Becerril, F.; Camps, E.; Villagran, M.; Muhl, S.

1998-01-01

In the present work it is showed the implementation of the plasma diagnostic technique through actinometry which allows to determine the absolute density of excited species. It is showed the range of the technique application, for the case of N 2 -H 2 mixtures plasmas used for the metals nitridation. The effects of magnetic field and the work pressure over ions energy were determined, using a Faraday cup type energy analyser. The results showed that in our device it is possible to vary such energy in a range between 10-45 eV, which amplify the range of applications perceptibly in comparison with another type of discharges. (Author)

Investigation on target normal sheath acceleration through measurements of ions energy distribution

Energy Technology Data Exchange (ETDEWEB)

Tudisco, S., E-mail: tudisco@lns.infn.it; Cirrone, G. A. P.; Mascali, D.; Schillaci, F. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via S. Sofia 62, 95123 Catania (Italy); Altana, C. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Università degli Studi di Catania, Via S. Sofia 64, 95123 Catania (Italy); Lanzalone, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via S. Sofia 62, 95123 Catania (Italy); Università degli Studi di Enna “Kore,” Via delle Olimpiadi, 94100 Enna (Italy); Muoio, A. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Messina, Viale F.S. D’Alcontres 31, 98166 Messina (Italy); Brandi, F. [Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Intense Laser Irradiation Laboratory, Via G. Moruzzi 1, 56124 Pisa (Italy); Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Cristoforetti, G.; Ferrara, P.; Fulgentini, L.; Koester, P. [Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Intense Laser Irradiation Laboratory, Via G. Moruzzi 1, 56124 Pisa (Italy); Labate, L.; Gizzi, L. A. [Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Intense Laser Irradiation Laboratory, Via G. Moruzzi 1, 56124 Pisa (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); and others

2016-02-15

An experimental campaign aiming at investigating the ion acceleration mechanisms through laser-matter interaction in femtosecond domain has been carried out at the Intense Laser Irradiation Laboratory facility with a laser intensity of up to 2 × 10{sup 19} W/cm{sup 2}. A Thomson parabola spectrometer was used to obtain the spectra of the ions of the different species accelerated. Here, we show the energy spectra of light-ions and we discuss their dependence on structural characteristics of the target and the role of surface and target bulk in the acceleration process.

Investigation on target normal sheath acceleration through measurements of ions energy distribution

International Nuclear Information System (INIS)

Tudisco, S.; Cirrone, G. A. P.; Mascali, D.; Schillaci, F.; Altana, C.; Lanzalone, G.; Muoio, A.; Brandi, F.; Cristoforetti, G.; Ferrara, P.; Fulgentini, L.; Koester, P.; Labate, L.; Gizzi, L. A.

2016-01-01

An experimental campaign aiming at investigating the ion acceleration mechanisms through laser-matter interaction in femtosecond domain has been carried out at the Intense Laser Irradiation Laboratory facility with a laser intensity of up to 2 × 10 19 W/cm 2 . A Thomson parabola spectrometer was used to obtain the spectra of the ions of the different species accelerated. Here, we show the energy spectra of light-ions and we discuss their dependence on structural characteristics of the target and the role of surface and target bulk in the acceleration process

Experimental apparatus to investigate interactions of low energy ions with solid surfaces, 1

International Nuclear Information System (INIS)

Tsukakoshi, Osamu; Narusawa, Tadashi; Mizuno, Masayasu; Sone, Kazuho; Ohtsuka, Hidewo.

1975-12-01

Experimental apparatus to study the surface phenomena has been designed, which is intended to solve the vacuum wall problems in future thermonuclear fusion reactors and large experimental tokamak devices. An ion source and the beam transport optics are provided for bombarding solid target surface with an ion beam of energy from 0.1 to 6 keV. Measuring instruments include an ion energy analyser, a quadrupole mass spectrometer, an Auger electron spectrometer, an electro-micro-balance, a neutral particle energy spectrometer and its calibration system. Pumping system consists of oil-free ultrahigh vacuum pumps. Various kinds of experiments will be carried out by using the apparatus: 1) sputtering by low energy ion bombardment, 2) re-emission of the incident particles during and after ion bombardment, 3) release of adsorbed and occluded gases in the solids by ion bombardment, and 4) backscattering of fast ions. The combinations of measuring instruments for each experiment and their relative positions in the vacuum chamber are described through detailed drawings. The fundamental aspect in design of the ion beam transport optics for a low energy ion beam which can no longer neglect the space charge effect is also discussed. (auth.)

Ion induced high energy electron emission from copper

International Nuclear Information System (INIS)

Ruano, G.; Ferron, J.

2008-01-01

We present measurements of secondary electron emission from Cu induced by low energy bombardment (1-5 keV) of noble gas (He + , Ne + and Ar + ) and Li + ions. We identify different potential and kinetic mechanisms and find the presence of high energetic secondary electrons for a couple of ion-target combinations. In order to understand the presence of these fast electrons we need to consider the Fermi shuttle mechanism and the different ion neutralization efficiencies.

Confinement characteristics of high-energy ions produced by ICRF heating in the large helical device

International Nuclear Information System (INIS)

Kumazawa, R; Saito, K; Torii, Y; Mutoh, T; Seki, T; Watari, T; Osakabe, M; Murakami, S; Sasao, M; Watanabe, T; Yamamoto, T; Notake, T; Takeuchi, N; Saida, T; Shimpo, F; Nomura, G; Yokota, M; Kato, A; Zao, Y; Okada, H; Isobe, M; Ozaki, T; Narihara, K; Nagayama, Y; Inagaki, S; Morita, S; Krasilnikov, A V; Idei, H; Kubo, S; Ohkubo, K; Sato, M; Shimozuma, T; Yoshimura, Y; Ikeda, K; Nagaoka, K; Oka, Y; Takeiri, Y; Tsumori, K; Ashikawa, N; Emoto, M; Funaba, H; Goto, M; Ida, K; Kobuchi, T; Liang, Y; Masuzaki, S; Minami, T; Miyazawa, J; Morisaki, T; Muto, S; Nakamura, Y; Nakanishi, H; Nishimura, K; Noda, N; Ohdachi, S; Peterson, B J; Sagara, A; Sakakibara, S; Sakamoto, R; Sato, K; Shoji, M; Suzuki, H; Tanaka, K; Toi, K; Tokuzawa, T; Watanabe, K Y; Yamada, I; Yamamoto, S; Yoshinuma, M; Yokoyama, M; Watanabe, K-Y; Kaneko, O; Kawahata, K; Komori, A; Ohyabu, N; Yamada, H; Yamazaki, K; Sudo, S; Matsuoka, K; Hamada, Y; Motojima, O; Fujiwara, M

2003-01-01

The behaviour of high-energy ions accelerated by an ion cyclotron range of frequency (ICRF) electric field in the large helical device (LHD) is discussed. A better confinement performance of high-energy ions in the inward-shifted magnetic axis configuration was experimentally verified by measuring their energy spectrum and comparing it with the effective temperature determined by an electron slowing down process. In the standard magnetic axis configuration a saturation of the measured tail temperature was observed as the effective temperature was increased. The ratio between these two quantities is a measure of the quality of transfer efficiency from high-energy ions to a bulk plasma; when this efficiency was compared with Monte Carlo simulations the results agreed fairly well. The ratio of the stored energy of the high-energy ions to that of the bulk plasma was measured using an ICRF heating power modulation method; it was deduced from phase differences between total and bulk plasma stored energies and the modulated ICRF heating power. The measured high energy fraction agreed with that calculated using the injected ICRF heating power, the transfer efficiency determined in the experiment and the confinement scaling of the LHD plasma

Kinetic energy and charge distributions of multiply charged ions produced by heavy ions and by synchrotron radiation

International Nuclear Information System (INIS)

Levin, J.C.; Biedermann, C.; Cederquist, H.; Liljeby, L.; Short, R.T.; Sellin, I.A.

1989-01-01

This paper contrasts two methods of production of multiply charged ions which may have application in future hot-atom chemistry experiments. Interest in extending the study of ion-atom collisions from MeV to keV to eV energies has grown rapidly in the last decade as previously inaccessible astrophysical, fusion, and spectroscopic problems have been addressed. One of these methods involves highly charged secondary beams formed from ions created in dilute gas samples irradiated by fast (MeV), high-charge-state, heavy ions. The measurements show, however, that such ions often have mean recoil energies two orders of magnitude higher than kinetic energies of ions in similar charge states resulting from vacancy cascades of atomic inner shells photoionized by synchrotron x rays. These results may be applicable to development of a cold source of highly charged ions featuring low energy spread and good angular definition. Results from other laboratories (Grandin et al at Ganil, Ullrich et al in Frankfurt, and Watson et al at Texas A ampersand M) will also be discussed

A comparison of ion beam measurements by retarding field energy analyzer and laser induced fluorescence in helicon plasma devices

Energy Technology Data Exchange (ETDEWEB)

Gulbrandsen, N., E-mail: njal.gulbrandsen@uit.no; Fredriksen, Å. [Department of Physics and Technology, UiT The Arctic University of Norway, 9037 Tromsø (Norway); Carr, J. [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States); Department of Physics, Texas Lutheran University, Seguin, Texas 78155 (United States); Scime, E. [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States)

2015-03-15

Both Laser-Induced Fluorescence (LIF) and Retarding Field Energy Analyzers (RFEA) have been applied to the investigation of beams formed in inductively coupled helicon plasmas. While the LIF technique provides a direct measurement of the velocity distribution in the plasma, the RFEA measures ion flux as a function of a retarding potential. In this paper, we present a method to compare the two techniques, by converting the LIF velocity distribution to an equivalent of a RFEA measurement. We applied this method to compare new LIF and RFEA measurements in two different experiments; the Hot Helicon Experiment (HELIX) - Large Experiment on Instabilities and Anisotropies (LEIA) at West Virginia University and Njord at University of Tromsø. We find good agreement between beam energies of the two methods. In agreement with earlier observations, the RFEA is found to measure ion beams with densities too low for the LIF to resolve. In addition, we present measurements of the axial development of the ion beam in both experiments. Beam densities drop exponentially with distance from the source, both in LIF and RFEA measurements. The effective quenching cross section from LIF in LEIA is found to be σ{sub b,*}=4×10{sup −19} m{sup 2}, and the effective beam collisional cross sections by RFEA in Njord to be σ{sub b}=1.7×10{sup −18} m{sup 2}.

The effect of work function changes on secondary ion energy spectra

International Nuclear Information System (INIS)

Wittmaack, K.

1983-01-01

The effect of work function changes on experimental secondary ion energy spectra is discussed. In agreement with theory the measured ion intensities frequently exhibit an exponential work function dependence. However, the predicted velocity dependence is only observed at fairly high secondary ion energies. In the absence of a velocity dependence of the degree of ionization measured shifts of energy spectra reflect work function changes directly. Various instrumental problems are shown to aggravate a detailed comparison between experiment and theory. Significant artefacts must be expected if the extraction field is of the order of or less than the lateral field induced by a work function difference between the bombarded spot and the surrounding sample surface. (Auth.)

Study on rice transformation mediated by low energy ion beam implantation

International Nuclear Information System (INIS)

Li Hong; Wu Lifang; Yu Zengliang

2001-01-01

Delivery of foreign DNA into rice via ion beam was first reported in 1994. In recent years we have aimed to set up efficient transformation system mediated by low energy ion beam. The factors that influence the transformation including type of ion, parameters of ion energy, dose and dose rate, plant genotype, composition of media, concentration of hormones and antibiotics were carefully investigated. Treated with 25ke V Ar + , the transformation efficiencies of the mature embryos of rice variety 02428, Hua pei94-jian-09 and Minghui63 reached 11%, 11.4% and 7.1% measured by produced antibiotic resistant callus and l.52%, 1.87% and l.13% measured by regenerated plants respectively. PCR detection and Southern blot analysis showed that GUS report gene had inserted in rice genome. Low energy ion beam mediated gene transfer will be extended to other cereal recalcitrant to Agrobacterium tumefaciens as soon as methodological parameters were optimized. (authors)

Charged Particle, Photon Multiplicity, and Transverse Energy Production in High-Energy Heavy-Ion Collisions

Directory of Open Access Journals (Sweden)

Raghunath Sahoo

2015-01-01

Full Text Available We review the charged particle and photon multiplicities and transverse energy production in heavy-ion collisions starting from few GeV to TeV energies. The experimental results of pseudorapidity distribution of charged particles and photons at different collision energies and centralities are discussed. We also discuss the hypothesis of limiting fragmentation and expansion dynamics using the Landau hydrodynamics and the underlying physics. Meanwhile, we present the estimation of initial energy density multiplied with formation time as a function of different collision energies and centralities. In the end, the transverse energy per charged particle in connection with the chemical freeze-out criteria is discussed. We invoke various models and phenomenological arguments to interpret and characterize the fireball created in heavy-ion collisions. This review overall provides a scope to understand the heavy-ion collision data and a possible formation of a deconfined phase of partons via the global observables like charged particles, photons, and the transverse energy measurement.

Ion induced high energy electron emission from copper

Energy Technology Data Exchange (ETDEWEB)

Ruano, G. [Instituto de Desarrollo Tecnologico para la Industria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Universidad Nacional del Litoral Gueemes 3450 CC 91, 3000 Santa Fe (Argentina)], E-mail: gdruano@ceride.gov.ar; Ferron, J. [Instituto de Desarrollo Tecnologico para la Industria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Universidad Nacional del Litoral Gueemes 3450 CC 91, 3000 Santa Fe (Argentina); Departamento de Ingenieria de Materiales, Facultad de Ingenieria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Universidad Nacional del Litoral Gueemes 3450 CC 91, 3000 Santa Fe (Argentina)

2008-11-15

We present measurements of secondary electron emission from Cu induced by low energy bombardment (1-5 keV) of noble gas (He{sup +}, Ne{sup +} and Ar{sup +}) and Li{sup +} ions. We identify different potential and kinetic mechanisms and find the presence of high energetic secondary electrons for a couple of ion-target combinations. In order to understand the presence of these fast electrons we need to consider the Fermi shuttle mechanism and the different ion neutralization efficiencies.

Measurements of the total energy lost per electron-ion pair lost in low-pressure inductive argon, helium, oxygen and nitrogen discharge

International Nuclear Information System (INIS)

Lee, Young-Kwang; Ku, Ju-Hwan; Chung, Chin-Wook

2011-01-01

Experimental measurements of the total energy lost per electron-ion pair lost, ε T , were performed in a low-pressure inductive atomic gases (Ar, He) and molecular gases (O 2 , N 2 ) discharge. The value of ε T was determined from a power balance based on the electropositive global (volume-averaged) model. A floating harmonic method was employed to measure ion fluxes and electron temperatures at the discharge wall. In the pressure range 5-50 mTorr, it was found that the measured ε T ranged from about 70 to 150 V for atomic gases, but from about 180 to 1300 V for molecular gases. This difference between atomic and molecular discharge is caused by additional collisional energy losses of molecular gases. For argon discharge, the stepwise ionization effect on ε T was observed at relatively high pressures. For different gases, the measured ε T was evaluated with respect to the electron temperature, and then compared with the calculation results, which were derived from collisional and kinetic energy loss. The measured ε T and their calculations showed reasonable agreement.

Effect of gas filling pressure and operation energy on ion and neutron emission in a medium energy plasma focus device

Science.gov (United States)

Niranjan, Ram; Rout, R. K.; Srivastava, Rohit; Kaushik, T. C.

2018-03-01

The effects of gas filling pressure and operation energy on deuterium ions and neutrons have been studied in a medium energy plasma focus device, MEPF-12. The deuterium gas filling pressure was varied from 1 to 10 mbar at an operation energy of 9.7 kJ. Also, the operation energy was varied from 3.9 to 9.7 kJ at a deuterium gas filling pressure of 4 mbar. Time resolved emission of deuterium ions was measured using a Faraday cup. Simultaneously, time integrated and time resolved emissions of neutrons were measured using a silver activation detector and plastic scintillator detector, respectively. Various characteristics (fluence, peak density, and most probable energy) of deuterium ions were estimated using the Faraday cup signal. The fluence was found to be nearly independent of the gas filling pressure and operation energy, but the peak density and most probable energy of deuterium ions were found to be varying. The neutron yield was observed to be varying with the gas filling pressure and operation energy. The effect of ions on neutrons emission was observed at each operation condition.

Equilibrium charge state distributions of high energy heavy ions

International Nuclear Information System (INIS)

Clark, R.B.; Grant, I.S.; King, R.; Eastham, D.A.; Joy, T.

1976-01-01

Equilibrium charge state fractions have been measured for N, O, Ne, S, Ar and Kr ions at 1.04 MeV/nucleon after passing through various stripping materials. Further data were obtained at higher energy for S ions (4.12 MeV/nucleon) and Ar ions (4.12 and 9.6 MeV/nucleon). The mean charge fractions can be fitted to universal curves for both solid and gaseous strippers. Measurements of the equilibrium fraction of krypton ions at 1.04 MeV/nucleon passing through heavy vapours have shown that a higher average charge state is obtained than for lighter gaseous strippers. (Auth.)

GEOS-2 measurements of cold ions in the magnetosheath

International Nuclear Information System (INIS)

Rodgers, D.J.; Johnstone, A.D.; Sojka, J.J.

1985-01-01

The Suprathermal Plasma Analysers on GEOS-2 are able to make differential energy measurements of plasma particles down to sub-eV energies because the entire sensor package can be biased relative to the spacecraft. When the package is biased negatively with respect to space potential, low energy positive ions are sucked in and are more easily detected against the background. Large fluxes of ions with temperatures of the order of 1 eV or less were consistently detected at space potential when the spacecraft was in the magnetosheath though not when it was in the nearby magnetosphere. This apparent geophysical correlation, suggesting that the ions were part of the magnetosheath ion population, was contradicted by the fact that the ions showed no signs of the large drift velocity associated with the electric field in the magnetosheath. It is concluded, after further investigation, that the observed ions were probably sputtered as neutrals from the spacecraft surface by the impact of solar wind ions and subsequently ionized by sunlight or electron impact. The effect of sputtering by solar wind ions has not been previously observed, although it could have consequences for the long-term stability of spacecraft surfaces. (author)

Modified Thomson spectrometer design for high energy, multi-species ion sources

International Nuclear Information System (INIS)

Gwynne, D.; Kar, S.; Doria, D.; Ahmed, H.; Hanton, F.; Cerchez, M.; Swantusch, M.; Willi, O.; Fernandez, J.; Gray, R. J.; MacLellan, D. A.; McKenna, P.; Green, J. S.; Neely, D.; Najmudin, Z.; Streeter, M.; Ruiz, J. A.; Schiavi, A.; Zepf, M.; Borghesi, M.

2014-01-01

A modification to the standard Thomson parabola spectrometer is discussed, which is designed to measure high energy (tens of MeV/nucleon), broad bandwidth spectra of multi-species ions accelerated by intense laser plasma interactions. It is proposed to implement a pair of extended, trapezoidal shaped electric plates, which will not only resolve ion traces at high energies, but will also retain the lower energy part of the spectrum. While a longer (along the axis of the undeflected ion beam direction) electric plate design provides effective charge state separation at the high energy end of the spectrum, the proposed new trapezoidal shape will enable the low energy ions to reach the detector, which would have been clipped or blocked by simply extending the rectangular plates to enhance the electrostatic deflection

Sn ion energy distributions of ns- and ps-laser produced plasmas

Science.gov (United States)

Bayerle, A.; Deuzeman, M. J.; van der Heijden, S.; Kurilovich, D.; de Faria Pinto, T.; Stodolna, A.; Witte, S.; Eikema, K. S. E.; Ubachs, W.; Hoekstra, R.; Versolato, O. O.

2018-04-01

Ion energy distributions arising from laser-produced plasmas of Sn are measured over a wide laser parameter space. Planar-solid and liquid-droplet targets are exposed to infrared laser pulses with energy densities between 1 J cm‑2 and 4 kJ cm‑2 and durations spanning 0.5 ps to 6 ns. The measured ion energy distributions are compared to two self-similar solutions of a hydrodynamic approach assuming isothermal expansion of the plasma plume into vacuum. For planar and droplet targets exposed to ps-long pulses, we find good agreement between the experimental results and the self-similar solution of a semi-infinite simple planar plasma configuration with an exponential density profile. The ion energy distributions resulting from solid Sn exposed to ns-pulses agrees with solutions of a limited-mass model that assumes a Gaussian-shaped initial density profile.

Investigations on the influence of ion kinetic energy on mass discrimination in isotope ratio measurements using MC-ICPMS

International Nuclear Information System (INIS)

Fontaine, G.H.; Hattendorf, B.; Oberli, F.; Bourdon, B.; Guenther, D.

2009-01-01

Full text: Systematic dependence of mass discrimination on ICP operating parameters was investigated for two MCICPMS instruments, a Nu Plasma HR and a Nu Plasma 1700, which differ both in acceleration voltage and spectrometer geometry. Gas temperature variations were determined by absolute pressure measurements at the vacuum interface. Their influence on ion kinetic energy as monitored by means of a retardation filter fitted in front of an ion counting detector will be discussed and compared to effects resulting from variations in acceleration voltage. (author)

Lifetime measurements using radioactive ion beams at intermediate energies and the Doppler shift method

Energy Technology Data Exchange (ETDEWEB)

Dewald, A.; Melon, B.; Pissulla, T.; Rother, W.; Fransen, C.; Moeller, O.; Zell, K.O.; Jolie, J. [IKP, Univ. zu Koeln (Germany); Petkov, P. [Bulg. Acad. of Science, INRNE, Solfia (Bulgaria); Starosta, K.; Przemyslaw, A.; Miller, D.; Chester, A.; Vaman, C.; Voss, P.; Gade, A.; Glasmacher, T.; Stolz, A.; Bazin, D.; Weisshaar, D. [NSCL, MSU, East Lansing (United States)

2007-07-01

Absolute transition probabilities are crucial quantities in nuclear structure physics. Therefore, it is important to establish Doppler shift (plunger) techniques also for the measurement of level lifetimes in radioactive ion beam experiments. After a first successful test of the Doppler Shift technique at intermediate energy (52MeV/u) with a stable {sup 124}Xe beam, a plunger has been built and used in two experiments, performed at the NSCL/MSU with the SEGA Ge-array and the S800 spectrometer. The aim of the first experiment was to investigate the plunger technique after a knock-out reaction using a radioactive {sup 65}Ge beam at 100 MeV/u for populating excited states in {sup 64}Ge. The second experiment aimed to measure the lifetimes of the first 2{sup +} states in {sup 110,114}Pd with the plunger technique after Coulomb excitation at beam energies of 54 MeV/u. First results of both experiments will be presented and discussed. (orig.)

High energy metal ion implantation using 'Magis', a novel, broad-beam, Marx-generator-based ion source

International Nuclear Information System (INIS)

Anders, A.; Brown, I.G.; Dickinson, M.R.; MacGill, R.A.

1996-08-01

Ion energy of the beam formed by an ion source is proportional to extractor voltage and ion charge state. Increasing the voltage is difficult and costly for extraction voltage over 100 kV. Here we explore the possibility of increasing the charge states of metal ions to facilitate high-energy, broad beam ion implantation at a moderate voltage level. Strategies to enhance the ion charge state include operating in the regimes of high-current vacuum sparks and short pulses. Using a time-of-flight technique we have measured charge states as high as 7+ (73 kA vacuum spark discharge) and 4+ (14 kA short pulse arc discharge), both for copper, with the mean ion charge states about 6.0 and 2.5, respectively. Pulsed discharges can conveniently be driven by a modified Marx generator, allowing operation of ''Magis'' with a single power supply (at ground potential) for both plasma production and ion extraction

Performance Limitations in High-Energy Ion Colliders

CERN Document Server

Fischer, Wolfram

2005-01-01

High-energy ion colliders (hadron colliders operating with species other than protons) are premier research tools for nuclear physics. The collision energy and high luminosity are important design and operations considerations. However, the experiments also expect flexibility with frequent changes in the collision energy, lattice configuration, and ion species, including asymmetric collisions. For the creation, acceleration, and storage of bright intense ion beams, attention must be paid to space charge, charge exchange, and intra-beam scattering effects. The latter leads to luminosity lifetimes of only a few hours for heavy ions. Ultimately cooling at full energy is needed to overcome this effect. Currently, the Relativistic Heavy Ion Collider at BNL is the only operating high-energy ion collider. The Large Hadron Collider, under construction at CERN, will also run with heavy ions.

Determination of low-energy ion-induced electron yields from thin carbon foils

International Nuclear Information System (INIS)

Allegrini, Frederic; Wimmer-Schweingruber, Robert F.; Wurz, Peter; Bochsler, Peter

2003-01-01

Ion beams crossing thin carbon foils can cause electron emission from the entrance and exit surface. Thin carbon foils are used in various types of time-of-flight (TOF) mass spectrometers to produce start pulses for TOF measurements. The yield of emitted electrons depends, among other parameters, on the energy of the incoming ion and its mass, and it has been experimentally determined for a few projectile elements. The electron emission yield is of great importance for deriving abundance ratios of elements and isotopes in space plasmas using TOF mass spectrometers. We have developed a detector for measuring ion-induced electron yields, and we have extended the electron yield measurements for oxygen to energies relevant for solar wind research. We also present first measurements of the carbon foil electron emission yield for argon and iron in the solar wind energy range

Mixed ion beams near transition energy

International Nuclear Information System (INIS)

Hancock, S.

1991-01-01

The standard derivations of the energy and phase of the synchronous particle in a proton accelerator assume, as if by definition, that said synchronous particle lies on the central orbit of the machine. This is manifestly unjustified in the particular case of the acceleration near transition of a mixture of ions, when a small difference in charge-to-mass ratio can produce a large radial separation of the different ion species. The development of a simple derivation of the parameters of the synchronous particle that involves no such a priori constraint has yielded some surprises; not, least, a belated explanation for an apparent anomaly encountered in 1987, when a mixture of oxygen and sulphur ions was accelerated in the CERN Proton Synchrotron for the first time. These ideas are supported by measurements performed in 1990 during a second ion run

Measurement of ejected electrons from collisions of He+ ions with He, Ne, and Ar at the intermediate energies

International Nuclear Information System (INIS)

Tokoro, Nobuhiro; Oda, Nobuo

1985-01-01

The doubly differential cross sections for electron production, differential in angle and energy of the electrons, for 5-25 keV He + impact on helium, neon and argon have been measured in the electron energy range of 2-200 eV at the ejection angles from 30 0 to 150 0 with respect to the incident ion beam. The characteristic features of continnum parts of ejected electron spectra are described for each collision system. (author)

Ion temperature measurements in the Maryland Spheromak

International Nuclear Information System (INIS)

Gauvreau, J.L.

1992-01-01

Initial spectroscopic data from MS showed evidence of ion heating as deduced from the line widths of different ion species. Detailed measurements of OIV spectral emission line profiles in space and time revealed that heating takes place at early time, before spheromak formation and is occurring within the current discharge. The measured ion temperature is several times the electron temperature and cannot be explained by classical (Spitzer) resistivity. Classically, ions are expected to have lower temperatures than the electrons and therefore, lower temperatures than observed. High ion temperatures have been observed in different RFP's and Spheromaks but are usually associated with relaxation to the Taylor state and occur in the sustainment phase. During formation, the current delivered to start the discharge is not axisymmetric and as a consequence, X-points appear in the magnetic flux. A two dimensional analysis predicts that magnetic reconnection occurring at an X-point can give rise to high ion heating rates. A simple 0-dimensional calculation showed that within the first 20 μs, a conversion of mass flow kinetic energy into ion temperature could take place due to viscosity

Interaction of low-energy highly charged ions with matter

International Nuclear Information System (INIS)

Ginzel, Rainer

2010-01-01

The thesis presented herein deals with experimental studies of the interaction between highly charged ions and neutral matter at low collision energies. The energy range investigated is of great interest for the understanding of both charge exchange reactions between ions comprising the solar wind and various astrophysical gases, as well as the creation of near-surface nanostructures. Over the course of this thesis an experimental setup was constructed, capable of reducing the kinetic energy of incoming ions by two orders of magnitude and finally focussing the decelerated ion beam onto a solid or gaseous target. A coincidence method was employed for the simultaneous detection of photons emitted during the charge exchange process together with the corresponding projectile ions. In this manner, it was possible to separate reaction channels, whose superposition presumably propagated large uncertainties and systematic errors in previous measurements. This work has unveiled unexpectedly strong contributions of slow radiative decay channels and clear evidence of previously only postulated decay processes in charge exchange-induced X-ray spectra. (orig.)

Energy loss measurements of {sup 63}Cu, {sup 28}Si and {sup 27}Al heavy ions crossing thin Polyvinylchloride (PVC) foil

Energy Technology Data Exchange (ETDEWEB)

Dib, A.; Ammi, H. [Centre de Recherche Nucléaire d’Alger, 2 Bd. Frantz Fanon, B.P. 399, Alger-Gare, Algiers (Algeria); Guesmia, A., E-mail: guesmia@tlabs.ac.za [Departement de physique, Faculté des Sciences, Université Saad Dahlab, B. P. 270, Route de Soumaa, Blida (Algeria); Departement de physique, Faculté des Sciences, Université M’hamed Bougara, Boumerdes (Algeria); iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Msimanga, M. [Department of Physics, Arcadia Campus, Tshwane University of Technology, P. Bag X680, Pretoria (South Africa); Mammeri, S. [Centre de Recherche Nucléaire d’Alger, 2 Bd. Frantz Fanon, B.P. 399, Alger-Gare, Algiers (Algeria); Hedibel, M. [Departement de physique, Faculté des Sciences, Université M’hamed Bougara, Boumerdes (Algeria); Guedioura, B. [Centre de Recherche Nucléaire de Draria, B.P. 43, Sebala-Draria, Algiers (Algeria); Pineda-Vargas, C.A. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Faculty of Health and Wellness Sciences, CPUT, P.O. Box 1906, Bellville 7535 (South Africa)

2015-11-15

Experimental stopping data of, {sup 63}Cu, {sup 28}Si and {sup 27}Al heavy ions in thin Polyvinylchloride (H{sub 3}C{sub 2}Cl{sub 1}) foil have been obtained over the 0.045–0.50 MeV/nucleon energy range. The measured energy losses were carried out by Heavy Ion Elastic Recoil Detection Analysis (HI-ERDA) technique coupled with time of flight (ToF) spectrometer. A continuous stopping power data obtained in this work are well fitted by our proposed semi-empirical formula and the results are compared to those calculated by LSS formula or generated by SRIM-2013 and MSTAR predictions. Calculations using our formula agree well with the obtained experimental stopping powers, while the LSS formula underestimates the experimental data in the whole investigated energy range. In this work a simple expression for electronic stopping power of heavy ions at low energy in solid targets is introduced. This formula is based on the Firsov and Lindhard–Sharff stopping power models with a small modification made to the original expression, by incorporating the effective charge of moving ions concept and with exponential fit function.

Measurements of scattering processes in negative ion-atom collisions

International Nuclear Information System (INIS)

Kvale, T.J.

1992-01-01

This Technical Progress Report describes the progress made on the research objectives during the past twelve months. This research project is designed to provide measurements of various scattering processes which occur in H - collisions with atomic (specifically, noble gas and atomic hydrogen) targets at intermediate energies. These processes include: elastic scattering,single- and double-electron detachment, and target excitation/ionization. For the elastic and target inelastic processes where H - is scattered intact, the experimental technique of Ion Energy-Loss Spectroscopy (IELS) will be employed to identify the final target state(s). In most of the above processes, cross sections are unknown both experimentally and theoretically. The measurements in progress will provide either experimentally-determined cross sections or set upper limits to those cross sections. In either case, these measurements will be stringent tests of our understanding in energetic negative ion-atom collisions. This series of experiments required the construction of a new facility and the initial ion beam was accelerated through the apparatus in April 1991

Measurement of omega, the energy required to create an ion pair, for 150-MeV protons in nitrogen and argon

International Nuclear Information System (INIS)

Petti, P.L.

1985-01-01

The purpose of this thesis is to provide a 1% measurement of omega, the energy required to produce an ion pair, for 150 MeV protons in various gases. Such a measurement should improve the accuracy of proton ionization chamber dosimetry at the Harvard Cyclotron Laboratory. Currently, no measurements of omega exist in the energy range of 30 to 150 MeV, and present ionization chamber dosimetry at the Cyclotron relies on average values of measurements at lower and higher energies (i.e. for E < 3 MeV and E = 340 MeV). Contrary to theoretical expectations, these low and high energy data differ by as much as 9% in some gases. The results of this investigation demonstrate that the existing high energy data is probably in error, and current proton ionization chamber dosimetry underestimates omega, and hence the proton dose, by 5%

Numerical calculation of 'actual' radial profile of ion temperature from 'measured' energy spectra of charge-exchanged neutrals

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Kazuo; Hiraki, Naoji; Toi, Kazuo; Itoh, Satoshi

1984-10-01

The energy spectra of charge-exchanged neutrals are observed in the TRIAM-1 tokamak by vertical scanning of the neutral energy analyzer. The ''apparent'' ion temperature obtained directly from the energy spectrum observed in the peripheral region is much higher than that predicted by neoclassical transport theory. The ''actual'' ion temperature profile is derived numerically from the energy spectra observed at various positions taking into account the wall-reflection effect of neutrals and the impermeability of the plasma. As a result, the ''actual'' ion temperature profile is found to agree well with that predicted by neoclassical transport theory.

Numerical calculation of 'actual' radial profile of ion temperature from 'measured' energy spectra of charge-exchanged neutrals

International Nuclear Information System (INIS)

Nakamura, Kazuo; Hiraki, Naoji; Toi, Kazuo; Itoh, Satoshi

1984-01-01

The energy spectra of charge-exchanged neutrals are observed in the TRIAM-1 tokamak by vertical scanning of the neutral energy analyzer. The ''apparent'' ion temperature obtained directly from the energy spectrum observed in the peripheral region is much higher than that predicted by neoclassical transport theory. The ''actual'' ion temperature profile is derived numerically from the energy spectra observed at various positions taking into account the wall-reflection effect of neutrals and the impermeability of the plasma. As a result, the ''actual'' ion temperature profile is found to agree well with that predicted by neoclassical transport theory. (author)

Flux threshold measurements of He-ion beam induced nanofuzz formation on hot tungsten surfaces

International Nuclear Information System (INIS)

Meyer, F W; Hijazi, H; Bannister, M E; Unocic, K A; Garrison, L M; Parish, C M

2016-01-01

We report measurements of the energy dependence of flux thresholds and incubation fluences for He-ion induced nano-fuzz formation on hot tungsten surfaces at UHV conditions over a wide energy range using real-time sample imaging of tungsten target emissivity change to monitor the spatial extent of nano-fuzz growth, corroborated by ex situ SEM and FIB/SEM analysis, in conjunction with accurate ion-flux profile measurements. The measurements were carried out at the multicharged ion research facility (MIRF) at energies from 218 eV to 8.5 keV, using a high-flux deceleration module and beam flux monitor for optimizing the decel optics on the low energy MIRF beamline. The measurements suggest that nano-fuzz formation proceeds only if a critical rate of change of trapped He density in the W target is exceeded. To understand the energy dependence of the observed flux thresholds, the energy dependence of three contributing factors: ion reflection, ion range and target damage creation, were determined using the SRIM simulation code. The observed energy dependence can be well reproduced by the combined energy dependences of these three factors. The incubation fluences deduced from first visual appearance of surface emissivity change were (2–4) × 10 23 m −2 at 218 eV, and roughly a factor of 10 less at the higher energies, which were all at or above the displacement energy threshold. The role of trapping at C impurity sites is discussed. (paper)

Energy- and angled-resolved photoelectron spectroscopy of negative ions

International Nuclear Information System (INIS)

Pegg, D.J.; Thompson, J.S.; Compton, R.N.; Alton, G.D.

1988-01-01

Energy- and angle-resolved photoelectron detachment spectroscopy is currently being used to investigate the structure of negative ions and their interaction with radiation. Measurements of the electron affinity of the Ca atom and the partial cross sections for photodetachment of the metastable negative ion, He - (1s2s2p 4 P), are reported. 5 refs., 5 figs

The low-energy-beam and ion-trap facility at NSCL/MSU

Energy Technology Data Exchange (ETDEWEB)

Schwarz, S. E-mail: schwarz@nscl.msu.edu; Bollen, G.; Lawton, D.; Lofy, P.; Morrissey, D.J.; Ottarson, J.; Ringle, R.; Schury, P.; Sun, T.; Varentsov, V.; Weissman, L

2003-05-01

The goal of the low-energy-beam and ion-trap (LEBIT) project is to convert the high-energy exotic beams produced at NSCL/MSU into low-energy low-emittance beams. This beam manipulation will be done by a combination of a high-pressure gas stopping cell and a radio-frequency quadrupole ion accumulator and buncher. The first experimental program to profit from the low-energy beams produced will be high-accuracy mass measurements on very short-lived isotopes with a 9.4 T Penning trap system. The status of the project is presented with an emphasis on recent stopping tests range of 100 MeV/A {sup 40}Ar{sup 18+} ions in a gas cell.

The low-energy-beam and ion-trap facility at NSCL/MSU

International Nuclear Information System (INIS)

Schwarz, S.; Bollen, G.; Lawton, D.; Lofy, P.; Morrissey, D.J.; Ottarson, J.; Ringle, R.; Schury, P.; Sun, T.; Varentsov, V.; Weissman, L.

2003-01-01

The goal of the low-energy-beam and ion-trap (LEBIT) project is to convert the high-energy exotic beams produced at NSCL/MSU into low-energy low-emittance beams. This beam manipulation will be done by a combination of a high-pressure gas stopping cell and a radio-frequency quadrupole ion accumulator and buncher. The first experimental program to profit from the low-energy beams produced will be high-accuracy mass measurements on very short-lived isotopes with a 9.4 T Penning trap system. The status of the project is presented with an emphasis on recent stopping tests range of 100 MeV/A 40 Ar 18+ ions in a gas cell

Spatially-Resolved Ion Trajectory Measurements During Cl2 Reactive Ion Beam Etching and Ar Ion Beam Etching

International Nuclear Information System (INIS)

Vawter, G. Allen; Woodworth, Joseph R.; Zubrzycki, Walter J.

1999-01-01

The angle of ion incidence at the etched wafer location during RIBE and IBE using Cl 2 , Ar and O 2 ion beams has been characterized using an ion energy and angle analyzer. Effects of beam current and accelerator grid bias on beam divergence and the spatial uniformity of the spread of incident angles are measured. It is observed that increased total beam current can lead to reduced current density at the sample stage due to enhanced beam divergence at high currents. Results are related to preferred etch system design for uniform high-aspect-ratio etching across semiconductor wafers

Damage growth in Si during self-ion irradiation: A study of ion effects over an extended energy range

International Nuclear Information System (INIS)

Holland, O.W.; El-Ghor, M.K.; White, C.W.

1989-01-01

Damage nucleation/growth in single-crystal Si during ion irradiation is discussed. For MeV ions, the rate of growth as well as the damage morphology are shown to vary widely along the track of the ion. This is attributed to a change in the dominant, defect-related reactions as the ion penetrates the crystal. The nature of these reactions were elucidated by studying the interaction of MeV ions with different types of defects. The defects were introduced into the Si crystal prior to high-energy irradiation by self-ion implantation at a medium energy (100 keV). Varied damage morphologies were produced by implanting different ion fluences. Electron microscopy and ion-channeling measurements, in conjunction with annealing studies, were used to characterize the damage. Subtle changes in the predamage morphology are shown to result in markedly different responses to the high-energy irradiation, ranging from complete annealing of the damage to rapid growth. These divergent responses occur over a narrow range of dose (2--3 times 10 14 cm -2 ) of the medium-energy ions; this range also marks a transition in the growth behavior of the damage during the predamage implantation. A model is proposed which accounts for these observations and provides insight into ion-induced growth of amorphous layers in Si and the role of the amorphous/crystalline interface in this process. 15 refs, 9 figs

Heavy ion collisions at intermediate energy

International Nuclear Information System (INIS)

Bertsch, G.; Amsden, A.A.

1978-01-01

Two types of measurement are proposed for the analysis of heavy ion collisions in the range of energy of 20--200 MeV/A. First, measurement of the longitudinal component of the kinetic energy of the collision products characterizes the impact parameter of the collision. The distribution in this quantity allows the dissipation in the theoretical models to be determined. A second kind of measurement is that of the coefficients of a spherical harmonic expansion of the angular distribution of the products. Besides giving independent information on the impact parameter and reaction dynamics, measurement of these coefficients offers the possibility of measuring the stiffness of the equation of state of nuclear matter. These ideas are explored in the context of a hydrodynamic model for the collision. In the purely hydrodynamic model there is a large measurable asymmetry in the angular distribution, but the dependence on the equation of state is small

Reaction mechanism in high energy heavy-ion collisions

International Nuclear Information System (INIS)

Tanihata, Isao.

1982-04-01

The reaction mechanism in high energy heavy-ion collision is discussed. The discussion is mainly based on the experimental data. Empirical equations have been given for the total cross-sections of nucleus-nucleus reactions and the reaction cross-sections. These cross-sections are well described by the geometrical size of the colliding nuclei. The cross-sections are also understood by microscopic calculation. The charged particle multiplicity gives additional information about the geometrical aspect of heavy ion collision. The data suggested that the total energy, independent of projectile size, is most important for determining the multiplicity. The inclusive proton spectrum in a heavy ion collision showed two distinct regions. The one is the fragment region, and the other the participant region. The spectral shapes of inclusive pion spectra are reasonably well explained by the Coulomb interaction of pions with nuclear fragments. The high energy heavy ion reaction occurs in the overlap region of the projectile and target. This has been tested by measuring the number of participants for various reactions. The space and the time structure of the collision are also discussed in this paper as well as the dynamical aspects of the collision. (Kato, T.)

Surface potential measurement of the insulator with secondary electron caused by negative ion implantation

International Nuclear Information System (INIS)

Tsuji, Hiroshi; Toyota, Yoshitaka; Nagumo, Syoji; Gotoh, Yasuhito; Ishikawa, Junzo; Sakai, Shigeki; Tanjyo, Masayasu; Matsuda, Kohji.

1994-01-01

Ion implantation has the merit of the good controllability of implantation profile and low temperature process, and has been utilized for the impurity introduction in LSI production. However, positive ion implantation is carried out for insulator or insulated conductor substrates, their charged potential rises, which is a serious problem. As the requirement for them advanced, charge compensation method is not the effective means for resolving it. The negative ion implantation in which charging is little was proposed. When the experiment on the negative ion implantation into insulated conductors was carried out, it was verified that negative ion implantation is effective as the implantation process without charging. The method of determining the charged potential of insulators at the time of negative ion implantation by paying attention to the energy distribution of the secondary electrons emitted from substrates at the time was devised. The energy analyzer for measuring the energy distribution of secondary electrons was made, and the measurement of the charged potential of insulators was carried out. The principle of the measurement, the measuring system and the experimental results are reported. (K.I.)

Trajectory bending and energy spreading of charged ions in time-of-flight telescopes used for ion beam analysis

International Nuclear Information System (INIS)

Laitinen, Mikko; Sajavaara, Timo

2014-01-01

Carbon foil time pick-up detectors are widely used in pairs in ion beam applications as time-of-flight detectors. These detectors are suitable for a wide energy range and for all ions but at the lowest energies the tandem effect limits the achievable time of flight and therefore the energy resolution. Tandem effect occurs when an ion passes the first carbon foil of the timing detector and its charge state is changed. As the carbon foil of the first timing detector has often a non-zero voltage the ion can accelerate or decelerate before and after the timing detector. The combination of different charge state properties before and after the carbon foil now induces spread to the measured times of flight. We have simulated different time pick-up detector orientations, voltages, ions and ion energies to examine the tandem effect in detail and found out that the individual timing detector orientation and the average ion charge state have a very small influence to the magnitude of the tandem effect. On the other hand, the width of the charge state distribution for particular ion and energy in the first carbon foil, and the carbon foil voltage contributes linearly to the magnitude of the tandem effect. In the simulations low energy light ion trajectories were observed to bend in the electric fields of the first timing gate, and the magnitude of this bending was studied. It was found out that 50–150 keV proton trajectories can even bend outside the second timing gate

High energy ion implantation for IC processing

International Nuclear Information System (INIS)

Oosterhoff, S.

1986-01-01

In this thesis the results of fundamental research on high energy ion implantation in silicon are presented and discussed. The implantations have been carried out with the 500 kV HVEE ion implantation machine, that was acquired in 1981 by the IC technology and Electronics group at Twente University of Technology. The damage and anneal behaviour of 1 MeV boron implantations to a dose of 10 13 /cm 2 have been investigated as a function of anneal temperature by sheet resistance, Hall and noise measurements. (Auth.)

Systematic investigations of low energy Ar ion beam sputtering of Si and Ag

Energy Technology Data Exchange (ETDEWEB)

Feder, R., E-mail: rene.feder@iom-leipzig.de [Leibniz-Institut für Oberflächenmodifizierung, Permoserstraße 15, 04318 Leipzig (Germany); Frost, F.; Neumann, H.; Bundesmann, C.; Rauschenbach, B. [Leibniz-Institut für Oberflächenmodifizierung, Permoserstraße 15, 04318 Leipzig (Germany)

2013-12-15

Ion beam sputter deposition (IBD) delivers some intrinsic features influencing the growing film properties, because ion properties and geometrical process conditions generate different energy and spatial distributions of the sputtered and scattered particles. Even though IBD has been used for decades, the full capabilities are not investigated systematically and specifically used yet. Therefore, a systematic and comprehensive analysis of the correlation between the properties of the ion beam, the generated secondary particles and backscattered ions and the deposited films needs to be done. A vacuum deposition chamber has been set up which allows ion beam sputtering of different targets under variation of geometrical parameters (ion incidence angle, position of substrates and analytics in respect to the target) and of ion beam parameters (ion species, ion energy) to perform a systematic and comprehensive analysis of the correlation between the properties of the ion beam, the properties of the sputtered and scattered particles, and the properties of the deposited films. A set of samples was prepared and characterized with respect to selected film properties, such as thickness and surface topography. The experiments indicate a systematic influence of the deposition parameters on the film properties as hypothesized before. Because of this influence, the energy distribution of secondary particles was measured using an energy-selective mass spectrometer. Among others, experiments revealed a high-energetic maximum for backscattered primary ions, which shifts with increasing emission angle to higher energies. Experimental data are compared with Monte Carlo simulations done with the well-known Transport and Range of Ions in Matter, Sputtering version (TRIM.SP) code [J.P. Biersack, W. Eckstein, Appl. Phys. A: Mater. Sci. Process. 34 (1984) 73]. The thicknesses of the films are in good agreement with those calculated from simulated particle fluxes. For the positions of the

Fast-ion Dα measurements of the fast-ion distribution (invited)

International Nuclear Information System (INIS)

Heidbrink, W. W.

2010-01-01

The fast-ion Dα (FIDA) diagnostic is an application of charge-exchange recombination spectroscopy. Fast ions that neutralize in an injected neutral beam emit Balmer-α light with a large Doppler shift. The spectral shift is exploited to distinguish the FIDA emission from other bright sources of Dα light. Background subtraction is the main technical challenge. A spectroscopic diagnostic typically achieves temporal, energy, and transverse spatial resolution of ∼1 ms, ∼10 keV, and ∼2 cm, respectively. Installations that use narrow-band filters achieve high spatial and temporal resolution at the expense of spectral information. For high temporal resolution, the bandpass-filtered light goes directly to a photomultiplier, allowing detection of ∼50 kHz oscillations in FIDA signal. For two-dimensional spatial profiles, the bandpass-filtered light goes to a charge-coupled device camera; detailed images of fast-ion redistribution at instabilities are obtained. Qualitative and quantitative models relate the measured FIDA signals to the fast-ion distribution function. The first quantitative comparisons between theory and experiment found excellent agreement in beam-heated magnetohydrodynamics (MHD)-quiescent plasmas. FIDA diagnostics are now in operation at magnetic-fusion facilities worldwide. They are used to study fast-ion acceleration by ion cyclotron heating, to detect fast-ion transport by MHD modes and microturbulence, and to study fast-ion driven instabilities.

Active ion temperature measurement with heating neutral beam

International Nuclear Information System (INIS)

Miura, Yukitoshi; Matsuda, Toshiaki; Yamamoto, Shin

1987-03-01

When the heating neutral-beam (hydrogen beam) is injected into a deuterium plasma, the density of neutral particles is increased locally. By using this increased neutral particles, the local ion temperature is measured by the active charge-exchange method. The analyzer is the E//B type mass-separated neutral particle energy analyzer and the measured position is about one third outside of the plasma radius. The deuterium energy spectrum is Maxwellian, and the temperature is increased from 350 eV to 900 eV during heating. Since the local hydrogen to deuterium density concentration and the density of the heating neutral-beam as well as the ion temperature can be obtained good S/N ratio, the usefulness of this method during neutral-beam heating is confirmed by this experiment. (author)

Mass and energy deposition effects of implanted ions on solid sodium formate

Energy Technology Data Exchange (ETDEWEB)

Wang Xiangqin E-mail: clshao@mail.ipp.ac.cn; Shao Chunlin; Yao Jianming; Yu Zengliang

2000-07-01

Solid sodium formate was implanted by low energy N{sup +}, H{sup +}, and Ar{sup +} ions. Measured with electron paramagnetic resonance (EPR) and Fourier-transform infrared (FT-IR), it was observed that new -CH{sub 2}-, -CH{sub 3}- groups and COO{sup -} radical ion were produced in the implanted sodium formate. Analyzing with the highly sensitive ninhydrin reaction, it was found that a new -NH{sub 2} functional group was formed upon N{sup +} ion implantation, and its yield increased along with implantation dose but decreased with the ion's energy.

Beam emittance measurements on multicusp ion sources

Energy Technology Data Exchange (ETDEWEB)

Sarstedt, M.; Lee, Y.; Leung, K.N. [and others

1995-08-01

Multicusp ion sources are used for various applications. Presently, the implementation of this type of ion source planned for the development of an ion beam lithography machine, which will be used for the projection of sub-0.2 {mu}m patterns onto a wafer substrate. Since, for this application, a very good beam quality and a small ion energy spread are required, emittance measurements have been performed on a multicusp ion source for various source conditions. It is shown that the installation of proper capacitors between the extraction electrodes is necessary to avoid rf-pickup, which otherwise leads to a distortion of the beam emittance. The influence of the magnetic filter field on the beam emittance has been investigated, and the beam emittance of a dc filament-discharge plasma has also been compared to that of an rf-generated plasma.

Beam emittance measurements on multicusp ion sources

International Nuclear Information System (INIS)

Sarstedt, M.; Lee, Y.; Leung, K.N.

1995-08-01

Multicusp ion sources are used for various applications. Presently, the implementation of this type of ion source planned for the development of an ion beam lithography machine, which will be used for the projection of sub-0.2 μm patterns onto a wafer substrate. Since, for this application, a very good beam quality and a small ion energy spread are required, emittance measurements have been performed on a multicusp ion source for various source conditions. It is shown that the installation of proper capacitors between the extraction electrodes is necessary to avoid rf-pickup, which otherwise leads to a distortion of the beam emittance. The influence of the magnetic filter field on the beam emittance has been investigated, and the beam emittance of a dc filament-discharge plasma has also been compared to that of an rf-generated plasma

The low-energy-beam and ion-trap facility at NSCL/MSU

CERN Document Server

Schwarz, S; Lawton, D; Lofy, P; Morrissey, D J; Ottarson, J; Ringle, R; Schury, P; Sun, T; Varentsov, V; Weissman, L

2003-01-01

The goal of the low-energy-beam and ion-trap (LEBIT) project is to convert the high-energy exotic beams produced at NSCL/MSU into low-energy low-emittance beams. This beam manipulation will be done by a combination of a high-pressure gas stopping cell and a radio-frequency quadrupole ion accumulator and buncher. The first experimental program to profit from the low-energy beams produced will be high-accuracy mass measurements on very short-lived isotopes with a 9.4 T Penning trap system. The status of the project is presented with an emphasis on recent stopping tests range of 100 MeV/A sup 4 sup 0 Ar sup 1 sup 8 sup + ions in a gas cell.

LEBIT - a low-energy beam and ion trap facility at NSCL/MSU

International Nuclear Information System (INIS)

Schwarz, S.; Bollen, G.; Davies, D.; Lawton, D.; Lofy, P.; Morrissey, D. J.; Ottarson, J.; Ringle, R.; Schury, P.; Sun, T.; VanWasshenova, D.; Sun, T.; Weissman, L.; Wiggins, D.

2003-01-01

The Low Energy Beam and Ion Trap (LEBIT) Project aims to convert the high-energy exotic beams produced at NSCL/MSU into low-energy low-emittance beams. A combination of a high-pressure gas stopping cell and a radiofrequency quadrupole (RFQ) ion accumulator and buncher will be used to manipulate the beam accordingly. High-accuracy mass measurements on very short-lived isotopes with a 9.4 T Penning trap system will be the first experimental program to profit from the low-energy beams. The status of the project is presented with a focus on recent stopping tests of 100-140 MeV/A Ar18+ ions in a gas cell

Origin of energetic ions in the polar cusp inferred from ion composition measurements by the Viking satellite

Directory of Open Access Journals (Sweden)

G. Kremser

1995-06-01

Full Text Available The magnetospheric ion composition spectrometer MICS on the Swedish Viking satellite provided measurements of the ion composition in the energy range 10.1 keV/e\\leqE/Q\\leq326.0 keV/e. Data obtained during orbit 842 were used to investigate the ion distribution in the northern polar cusp and its vicinity. The satellite traversed the outer ring current, boundary region, cusp proper and plasma mantle during its poleward movement. H+ and He++ ions were encountered in all of these regions. He+ ions were present only in the ring current. The number of O+ and O++ ions was very small. Heavy high-charge state ions typical for the solar wind were observed for the first time, most of them in the poleward part of the boundary region and in the cusp proper. The H+ ions exhibited two periods with high intensities. One of them, called the BR/CP event, appeared at energies up to 50 keV. It started at the equatorward limit of the boundary region and continued into the cusp proper. Energy spectra indicate a ring current origin for the BR/CP event. Pitch angle distributions show downward streaming of H+ ions at its equatorward limit and upward streaming on the poleward side. This event is interpreted as the result of pitch angle scattering of ring current ions by fluctuations in the magnetopause current layer in combination with poleward convection. The other of the two periods with high H+ ion intensities, called the accelerated ion event, was superimposed on the BR/CP event. It was restricted to energies \\leq15 keV and occurred in the poleward part of the boundary region. This event is regarded as the high-energy tail of magnetosheath ions that were accelerated while penetrating into the magnetosphere. The cusp region thus contains ions of magnetospheric as well as of magnetosheath origin. The appearance of the ions depends, in addition to the ion source, on the magnetic field configuration and dynamic processes inside and close to the cusp.

Analysis of In Situ Thermal Ion Measurements from the MICA Sounding Rocket

Science.gov (United States)

Fernandes, P. A.; Lynch, K. A.; Zettergren, M. D.; Hampton, D. L.; Fisher, L. E.; Powell, S. P.

2014-12-01

The MICA sounding rocket launched on 19 Feb. 2012 into several discrete, localized arcs in the wake of a westward traveling surge. In situ and ground-based observations provide a measured response of the ionosphere to preflight and localized auroral drivers. Initial analysis of the in situ thermal ion data indicate possible measurement of an ion conic at low altitude (< 325 km). In the low-energy regime, the response of the instrument varies from the ideal because the measured thermal ion population is sensitive to the presence of the instrument. The plasma is accelerated in the frame of the instrument due to flows, ram, and acceleration through the sheath which forms around the spacecraft. The energies associated with these processes are large compared to the thermal energy. Correct interpretation of thermal plasma measurements requires accounting for all of these plasma processes and the non-ideal response of the instrument in the low-energy regime. This is an experimental and modeling project which involves thorough analysis of ionospheric thermal ion data from the MICA campaign. Analysis includes modeling and measuring the instrument response in the low-energy regime as well as accounting for the complex sheath formed around the instrument. This results in a forward model in which plasma parameters of the thermal plasma are propagated through the sheath and instrument models, resulting in an output which matches the in situ measurement. In the case of MICA, we are working toward answering the question of the initiating source processes that result, at higher altitudes, in well-developed conics and outflow on auroral field lines.

A Thomson-type mass and energy spectrometer for characterizing ion energy distributions in a coaxial plasma gun operating in a gas-puff mode

OpenAIRE

Rieker, G. B.; Poehlmann, F. R.; Cappelli, M. A.

2013-01-01

Measurements of ion energy distribution are performed in the accelerated plasma of a coaxial electromagnetic plasma gun operating in a gas-puff mode at relatively low discharge energy (900 J) and discharge potential (4 kV). The measurements are made using a Thomson-type mass and energy spectrometer with a gated microchannel plate and phosphor screen as the ion sensor. The parabolic ion trajectories are captured from the sensor screen with an intensified charge-coupled detector camera. The spe...

Mass and energy analysis of the ions in a plasma flood system

International Nuclear Information System (INIS)

Wooding, A.C.; Armour, D.G.; Berg, J.A. van den; Holmes, A.J.T.; Burgess, C.; Goldberg, R.D.

2005-01-01

Plasma flood systems, capable of providing a copious supply of electrons are used in ion implanters to control wafer charging and provide effective space charge neutralisation of the ion beam in the post-analysis/post-deceleration section of the beamline. Under appropriate conditions the plasma from the flood system interacts with the ion beam and this bridging leads to an enhanced beam transport efficiency in the final critical stage of the beamline. The effectiveness of this process depends on the properties of the plasma emanating from the system. In this study, a plasma analyser comprising a double hemi-spherical electrostatic energy analyser and a quadrupole mass spectrometer, was used to measure the energy distributions of all the ion species leaving a magnetically confined argon plasma, generated in the discharge chamber of a conventional flood neutraliser. The energy distributions extended to surprisingly high energies and the peak structures depended strongly on discharge voltage, discharge current and gas pressure. The nature of these dependencies was complex with both the pressure and arc current affecting the way in which the ion energy distributions depended on arc voltage. In all cases, multiply charged ions played a significant role in determining the nature of the ion energy distributions

Mass and energy analysis of the ions in a plasma flood system

Energy Technology Data Exchange (ETDEWEB)

Wooding, A.C. [Institute of Materials Research, University of Salford, Salford M54WT (United Kingdom); Armour, D.G. [Institute of Materials Research, University of Salford, Salford M54WT (United Kingdom); Berg, J.A. van den [Institute of Materials Research, University of Salford, Salford M54WT (United Kingdom)]. E-mail: j.a.vandenberg@salford.ac.uk; Holmes, A.J.T. [Marcham Scientific, Hungerford, Berks RG17 0LH (United Kingdom); Burgess, C. [Applied Materials UK Ltd., Foundry Lane, Horsham, West Sussex RH13 5PX (United Kingdom); Goldberg, R.D. [Applied Materials UK Ltd., Foundry Lane, Horsham, West Sussex RH13 5PX (United Kingdom)

2005-08-01

Plasma flood systems, capable of providing a copious supply of electrons are used in ion implanters to control wafer charging and provide effective space charge neutralisation of the ion beam in the post-analysis/post-deceleration section of the beamline. Under appropriate conditions the plasma from the flood system interacts with the ion beam and this bridging leads to an enhanced beam transport efficiency in the final critical stage of the beamline. The effectiveness of this process depends on the properties of the plasma emanating from the system. In this study, a plasma analyser comprising a double hemi-spherical electrostatic energy analyser and a quadrupole mass spectrometer, was used to measure the energy distributions of all the ion species leaving a magnetically confined argon plasma, generated in the discharge chamber of a conventional flood neutraliser. The energy distributions extended to surprisingly high energies and the peak structures depended strongly on discharge voltage, discharge current and gas pressure. The nature of these dependencies was complex with both the pressure and arc current affecting the way in which the ion energy distributions depended on arc voltage. In all cases, multiply charged ions played a significant role in determining the nature of the ion energy distributions.

High-energy ion implantation of materials

International Nuclear Information System (INIS)

Williams, J.M.

1991-11-01

High-energy ion implantation is an extremely flexible type of surface treatment technique, in that it offers the possibility of treating almost any type of target material or product with ions of almost any chemical species, or combinations of chemical species. In addition, ion implantations can be combined with variations in temperature during or after ion implantation. As a result, the possibility of approaching a wide variety of surface-related materials science problems exists with ion implantation. This paper will outline factors pertinent to application of high-energy ion implantation to surface engineering problems. This factors include fundamental advantages and limitations, economic considerations, present and future equipment, and aspects of materials science

The GOES-16 Energetic Heavy Ion Sensor (EHIS) Ion Composition and Flux Measurements

Science.gov (United States)

Connell, J. J.; Lopate, C.

2017-12-01

The Energetic Heavy Ion Sensor (EHIS) was built by the University of New Hampshire, subcontracted to Assurance Technology Corporation, as part of the Space Environmental In-Situ Suite (SEISS) on the new GOES-16 satellite (formerly GOES-R) in Geostationary orbit. EHIS measures energetic ions over the range 10-200 MeV for protons, and energy ranges for heavy ions corresponding to the same stopping range (e.g., 19-207 MeV/u for carbon and 38-488 MeV/u for iron). EHIS uses the Angle Detecting Inclined Sensors (ADIS) technique to provide single-element charge resolution. Though on an operational mission for Space Weather monitoring, EHIS can thus provide a new source of high quality Solar Particle Event (SPE) data for science studies. With a high rate of on-board processing ( 2000 events/s), EHIS will provide exceptional statistics for ion composition measurements in large SPEs. For the GOES Level 1-B and Level 2 data products, heavy ions are distinguished in EHIS using pulse-height analysis with on-board processing producing charge histograms for five energy bands. Fits to these data are normalized to priority rate data on the ground. The instrumental cadence for histograms is 1 minute and the primary Level 1-B heavy ion data products are 1-minute and 5-minute averages. We discuss the preliminary EHIS heavy ion data results which show elemental peaks from H to Fe, with peaks for the isotopes D and 3He. (GOES-16 was launched in 19 November, 2016 and data has, though July 2017, been dominated by Galactic Cosmic Rays.) The EHIS instrument development project was funded by NASA under contract NNG06HX01C.

Monitoring Ion Implantation Energy Using Non-contact Characterization Methods

Science.gov (United States)

Tallian, M.; Pap, A.; Mocsar, K.; Somogyi, A.; Nadudvari, Gy.; Kosztka, D.; Pavelka, T.

2011-01-01

State-of-the-art ultra-shallow junctions are produced using extremely low ion implant energies, down to the range of 1-3 keV. This can be achieved by a variety of production techniques; however there is a significant risk that the actual implantation energy differs from the desired value. To detect this, sensitive measurement methods need to be utilized. Experiments show that both Photomodulated Reflection measurements before anneal and Junction Photovoltage-based sheet resistance measurements after anneal are suitable for this purpose.

Energy Loss of Coasting Gold Ions and Deuterons in RHIC

CERN Document Server

Abreu, N P; Brown, K; Burkhardt, H; Butler, J; Fischer, W; Harvey, M; Tepikian, S

2008-01-01

The total energy loss of coasting gold ion beams at two different energies and deuterons at one energy were measured at RHIC, corresponding to a gamma of 75.2, 107.4 and 108.7 respectively. We describe the experiment and observations and compare the measured total energy loss with expectations from ionization losses at the residual gas, the energy loss due to impedance and synchrotron radiation. We find that the measured energy losses are below what is expected from free space synchrotron radiation. We believe that this shows evidence for suppression of synchrotron radiation which is cut off at long wavelength by the presence of the conducting beam pipe.

The stopping powers and energy straggling of heavy ions in polymer foils

Energy Technology Data Exchange (ETDEWEB)

Mikšová, R., E-mail: miksova@ujf.cas.cz [Nuclear Physics Institute of the Academy of Sciences of the Czech Republic, v.v.i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Macková, A.; Malinský, P. [Nuclear Physics Institute of the Academy of Sciences of the Czech Republic, v.v.i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Hnatowicz, V. [Nuclear Physics Institute of the Academy of Sciences of the Czech Republic, v.v.i., 250 68 Rez (Czech Republic); Slepička, P. [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic)

2014-07-15

The stopping power and energy straggling of {sup 7}Li, {sup 12}C and {sup 16}O ions in thin poly(etheretherketone) (PEEK), polyethylene terephthalate (PET) and polycarbonate (PC) foils were measured in the incident beam energy range of 9.4–11.8 MeV using an indirect transmission method. Ions scattered from a thin gold target at an angle of 150° were registered by a partially depleted PIPS detector, partly shielded with a polymer foil placed in front of the detector. Therefore, the signals from both direct and slowed down ions were visible in the same energy spectrum, which was evaluated by the ITAP code, developed at our laboratory. The ITAP code was employed to perform a Gaussian-fitting procedure to provide a complete analysis of each measured spectrum. The measured stopping powers were compared with the predictions obtained from the SRIM-2008 and MSTAR codes and with previous experimental data. The energy straggling data were compared with those calculated by using Bohr’s, Lindhard–Scharff and Bethe–Livingston theories.

The stopping powers and energy straggling of heavy ions in polymer foils

International Nuclear Information System (INIS)

Mikšová, R.; Macková, A.; Malinský, P.; Hnatowicz, V.; Slepička, P.

2014-01-01

The stopping power and energy straggling of 7 Li, 12 C and 16 O ions in thin poly(etheretherketone) (PEEK), polyethylene terephthalate (PET) and polycarbonate (PC) foils were measured in the incident beam energy range of 9.4–11.8 MeV using an indirect transmission method. Ions scattered from a thin gold target at an angle of 150° were registered by a partially depleted PIPS detector, partly shielded with a polymer foil placed in front of the detector. Therefore, the signals from both direct and slowed down ions were visible in the same energy spectrum, which was evaluated by the ITAP code, developed at our laboratory. The ITAP code was employed to perform a Gaussian-fitting procedure to provide a complete analysis of each measured spectrum. The measured stopping powers were compared with the predictions obtained from the SRIM-2008 and MSTAR codes and with previous experimental data. The energy straggling data were compared with those calculated by using Bohr’s, Lindhard–Scharff and Bethe–Livingston theories

Energy and angle resolved ion scattering spectroscopy: new possibilities for surface analysis

International Nuclear Information System (INIS)

Hellings, G.J.A.

1986-01-01

In this thesis the design and development of a novel, very sensitive and high-resolving spectrometer for surface analysis is described. This spectrometer is designed for Energy and Angle Resolved Ion Scattering Spectroscopy (EARISS). There are only a few techniques that are sensitive enough to study the outermost atomic layer of surfaces. One of these techniques, Low-Energy Ion Scattering (LEIS), is discussed in chapter 2. Since LEIS is destructive, it is important to make a very efficient use of the scattered ions. This makes it attractive to simultaneously carry out energy and angle dependent measurements (EARISS). (Auth.)

Calibration of solid state nuclear track detectors at high energy ion beams for cosmic radiation measurements: HAMLET results

International Nuclear Information System (INIS)

Szabó, J.; Pálfalvi, J.K.

2012-01-01

The MATROSHKA experiments and the related HAMLET project funded by the European Commission aimed to study the dose burden of the crew working on the International Space Station (ISS). During these experiments a human phantom equipped with several thousands of radiation detectors was exposed to cosmic rays inside and outside the ISS. Besides the measurements realized in Earth orbit, the HAMLET project included also a ground-based program of calibration and intercomparison of the different detectors applied by the participating groups using high-energy ion beams. The Space Dosimetry Group of the Centre for Energy Research (formerly Atomic Energy Research Institute) participated in these experiments with passive solid state nuclear track detectors (SSNTDs). The paper presents the results of the calibration experiments performed in the years 2008–2011 at the Heavy Ion Medical Accelerator (HIMAC) of the National Institute of Radiological Sciences (NIRS), Chiba, Japan. The data obtained serve as update and improvement for the previous calibration curves which are necessary for the evaluation of the SSNTDs exposed in unknown space radiation fields.

Calibration of solid state nuclear track detectors at high energy ion beams for cosmic radiation measurements: HAMLET results

Energy Technology Data Exchange (ETDEWEB)

Szabo, J., E-mail: julianna.szabo@energia.mta.hu [Hungarian Academy of Sciences, Centre for Energy Research, Konkoly Thege Miklos ut 29-33, 1525 Budapest 114, P.O. Box 49 (Hungary); Palfalvi, J.K. [Hungarian Academy of Sciences, Centre for Energy Research, Konkoly Thege Miklos ut 29-33, 1525 Budapest 114, P.O. Box 49 (Hungary)

2012-12-01

The MATROSHKA experiments and the related HAMLET project funded by the European Commission aimed to study the dose burden of the crew working on the International Space Station (ISS). During these experiments a human phantom equipped with several thousands of radiation detectors was exposed to cosmic rays inside and outside the ISS. Besides the measurements realized in Earth orbit, the HAMLET project included also a ground-based program of calibration and intercomparison of the different detectors applied by the participating groups using high-energy ion beams. The Space Dosimetry Group of the Centre for Energy Research (formerly Atomic Energy Research Institute) participated in these experiments with passive solid state nuclear track detectors (SSNTDs). The paper presents the results of the calibration experiments performed in the years 2008-2011 at the Heavy Ion Medical Accelerator (HIMAC) of the National Institute of Radiological Sciences (NIRS), Chiba, Japan. The data obtained serve as update and improvement for the previous calibration curves which are necessary for the evaluation of the SSNTDs exposed in unknown space radiation fields.

The stopping power and energy straggling of heavy ions in silicon nitride and polypropylene

Energy Technology Data Exchange (ETDEWEB)

Mikšová, R., E-mail: miksova@ujf.cas.cz [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v. i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J. E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Hnatowicz, V. [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v. i., 250 68 Rez (Czech Republic); Macková, A.; Malinský, P. [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v. i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J. E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Slepička, P. [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic)

2015-07-01

The stopping power and energy straggling of {sup 12}C{sup 3+} and {sup 16}O{sup 3+} ions with energies between 4.5 and 7.8 MeV in a 0.166-μm-thin silicon nitride and in 4-μm-thin polypropylene foils were measured by means of an indirect transmission method using a half-covered PIPS detector. Ions scattered from a thin gold layer under a scattering angle of 150° were used. The energy spectra of back-scattered and decelerated ions were registered and evaluated simultaneously. The measured stopping powers were compared with the theoretical predictions simulated by SRIM-2008 and MSTAR codes. SRIM prediction of energy stopping is reasonably close to the experimentally obtained values comparing to MSTAR values. Better agreement between experimental and predicted data was observed for C{sup 3+} ion energy losses comparing to O{sup 3+} ions. The experimental data from Paul’s database and our previous experimental data were also discussed. The obtained experimental energy-straggling data were compared to those calculated by using Bohr’s, Yang’s models etc. The predictions by Yang are in good agreement with our experiment within a frame of uncertainty of 25%.

The stopping power and energy straggling of heavy ions in silicon nitride and polypropylene

International Nuclear Information System (INIS)

Mikšová, R.; Hnatowicz, V.; Macková, A.; Malinský, P.; Slepička, P.

2015-01-01

The stopping power and energy straggling of 12 C 3+ and 16 O 3+ ions with energies between 4.5 and 7.8 MeV in a 0.166-μm-thin silicon nitride and in 4-μm-thin polypropylene foils were measured by means of an indirect transmission method using a half-covered PIPS detector. Ions scattered from a thin gold layer under a scattering angle of 150° were used. The energy spectra of back-scattered and decelerated ions were registered and evaluated simultaneously. The measured stopping powers were compared with the theoretical predictions simulated by SRIM-2008 and MSTAR codes. SRIM prediction of energy stopping is reasonably close to the experimentally obtained values comparing to MSTAR values. Better agreement between experimental and predicted data was observed for C 3+ ion energy losses comparing to O 3+ ions. The experimental data from Paul’s database and our previous experimental data were also discussed. The obtained experimental energy-straggling data were compared to those calculated by using Bohr’s, Yang’s models etc. The predictions by Yang are in good agreement with our experiment within a frame of uncertainty of 25%

Live cell imaging combined with high-energy single-ion microbeam

Science.gov (United States)

Guo, Na; Du, Guanghua; Liu, Wenjing; Guo, Jinlong; Wu, Ruqun; Chen, Hao; Wei, Junzhe

2016-03-01

DNA strand breaks can lead to cell carcinogenesis or cell death if not repaired rapidly and efficiently. An online live cell imaging system was established at the high energy microbeam facility at the Institute of Modern Physics to study early and fast cellular response to DNA damage after high linear energy transfer ion radiation. The HT1080 cells expressing XRCC1-RFP were irradiated with single high energy nickel ions, and time-lapse images of the irradiated cells were obtained online. The live cell imaging analysis shows that strand-break repair protein XRCC1 was recruited to the ion hit position within 20 s in the cells and formed bright foci in the cell nucleus. The fast recruitment of XRCC1 at the ion hits reached a maximum at about 200 s post-irradiation and then was followed by a slower release into the nucleoplasm. The measured dual-exponential kinetics of XRCC1 protein are consistent with the proposed consecutive reaction model, and the measurements obtained that the reaction rate constant of the XRCC1 recruitment to DNA strand break is 1.2 × 10-3 s-1 and the reaction rate constant of the XRCC1 release from the break-XRCC1 complex is 1.2 × 10-2 s-1.

Ion trapping in the high-energy storage ring HESR

Energy Technology Data Exchange (ETDEWEB)

Hinterberger, Frank [Bonn Univ. (Germany). Helmholtz-Institut fuer Strahlen- und Kernphysik

2011-10-15

The problem of ion trapping in the high-energy storage ring HESR is studied in the present report. Positive ions are trapped in the negative potential well of the antiproton beam. The ions are produced by the interaction between the antiproton beam and the residual gas. The adverse effects of ion trapping like tune shifts, tune spreads and coherent instabilities are reviewed. The ion production rate by ionization of the residual gas molecules is estimated. The negative potential well and the corresponding electric fields of the antiproton beam are evaluated in order to study the transverse and longitudinal motion of the ions and the accumulation in trapping pockets. The removal of ions can be achieved using clearing electrodes and under certain conditions resonant transverse beam shaking. Diagnostic tools and measurements of trapped ion effects are sketched. (orig.)

Visualization and analysis of pulsed ion beam energy density profile with infrared imaging

Science.gov (United States)

Isakova, Y. I.; Pushkarev, A. I.

2018-03-01

Infrared imaging technique was used as a surface temperature-mapping tool to characterize the energy density distribution of intense pulsed ion beams on a thin metal target. The technique enables the measuring of the total ion beam energy and the energy density distribution along the cross section and allows one to optimize the operation of an ion diode and control target irradiation mode. The diagnostics was tested on the TEMP-4M accelerator at TPU, Tomsk, Russia and on the TEMP-6 accelerator at DUT, Dalian, China. The diagnostics was applied in studies of the dynamics of the target cooling in vacuum after irradiation and in the experiments with target ablation. Errors caused by the target ablation and target cooling during measurements have been analyzed. For Fluke Ti10 and Fluke Ti400 infrared cameras, the technique can achieve surface energy density sensitivity of 0.05 J/cm2 and spatial resolution of 1-2 mm. The thermal imaging diagnostics does not require expensive consumed materials. The measurement time does not exceed 0.1 s; therefore, this diagnostics can be used for the prompt evaluation of the energy density distribution of a pulsed ion beam and during automation of the irradiation process.

Electron capture by multicharged ions from hydrogen atoms at eV energies

International Nuclear Information System (INIS)

Havener, C.C.; Nesnidal, M.P.; Porter, M.R.; Phaneuf, R.A.

1990-01-01

To quantitatively study electron capture during collisions of multiply charged ions with neutral atoms at near-thermal energies, keV-energy multicharged ion beams are merged with ground-state beams of H or D atoms of chosen velocity such that collisions in the relative energy range 1--1000 eV/amu result. Recent data for O 3+ , O 4+ + H(D) are presented and compared with theoretical predictions. Recently completed modifications to the apparatus are described that will provide a significant improvement in signal-to-background and angular collection. These improvements will allow measurements to be extended to lower energies, where effects due to the ion-induced dipole attraction may be evident

The Mean Excitation Energy of Atomic Ions

DEFF Research Database (Denmark)

Sauer, Stephan; Oddershede, Jens; Sabin, John R.

2015-01-01

A method for calculation of the mean excitation energies of atomic ions is presented, making the calculation of the energy deposition of fast ions to plasmas, warm, dense matter, and complex biological systems possible. Results are reported to all ions of helium, lithium, carbon, neon, aluminum...

Time-resolved measurements of the focused ion beams on PBFA II

International Nuclear Information System (INIS)

Mix, L.P.; Stygar, W.A.; Leeper, R.J.; Maenchen, J.E.; Wenger, D.F.

1992-01-01

A time-resolved camera has been developed to image the intense ion beam focus on PBFA II. Focused ions from a sector of the ion diode are Rutherford scattered from a thin gold foil on the diode axis and pinhole imaged onto an array of up to 49 PIN detectors to obtain the spatially and temporally resolved images. The signals from these detectors are combined to provide a movie of the beam focus with a time resolution of about 3 ns and a spatial resolution of 2 mm over a 12 mm field of view. Monte Carlo simulations of the camera response are used with the measured ion energy to account for the time-of-flight dispersion of the beam and to convert the recorded signals to an intensity. From measurements on an 81 degree sector of the diode, average intensities on a 6 mm sphere of about 5 TW/cm 2 and energies approaching 80 kJ/cm 2 are calculated for standard proton diodes. Corresponding numbers for a lithium diode are less than those measured with protons. The details of the analysis and image reconstruction will be presented along with scaled images from recent ion focusing experiments

A measurement of the local ion temperature gradient in the PLT tokamak

International Nuclear Information System (INIS)

Lovberg, J.A.; Strachan, J.D.; Princeton Univ., NJ

1989-12-01

Local ion temperature gradients were measured at two radial positions in the PLT tokamak by counting escaping d(d,p)t protons on orbits at closely spaced intervals. A single surface barrier detector was used to make each gradient measurement, eliminating relative calibration uncertainties. The ion thermal diffusivities inferred through ion energy balance with the measured temperature gradients are within a factor of two of Chang-Hinton neoclassical values for the 3 He-minority ICRH plasmas. 12 refs., 8 figs

Ion temperature measurements of turbulently heated tokamak plasma by Doppler-broadening of visible lines in TRIAM-1

Energy Technology Data Exchange (ETDEWEB)

Hiraki, N; Nakamura, K; Toi, K; Itoh, S [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

1981-01-01

In the turbulent heating experiment of the high-field tokamak TRIAM-1, the bulk ion heating shown by the neutral energy analyzer measurement is confirmed by the Doppler broadening measurement of visible lines. The increasing rate and decay time of the Doppler ion temperature are almost the same as those derived from the neutral energy analyzer measurement. From both methods of ion temperature measurements, it is shown that the ion temperature has a parabolic profile within 50 ..mu..s after the application of the heating pulse.

Moderate energy ions for high energy density physics experiments

International Nuclear Information System (INIS)

Grisham, L.R.

2004-01-01

This paper gives the results of a preliminary exploration of whether moderate energy ions (≅0.3-3 MeV/amu) could be useful as modest-cost drivers for high energy density physics experiments. It is found that if the target thickness is chosen so that the ion beam enters and then leaves the target in the vicinity of the peak of the dE/dX (stopping power) curve, high uniformity of energy deposition may be achievable while also maximizing the amount of energy per beam particle deposited within the target

Measurement of stopping power of light ions

International Nuclear Information System (INIS)

Sakamoto, Naoki

1981-01-01

The stopping power of light ions penetrating various materials has been measured. The data of proton stopping power and the mean ionization potentials are presented. The experiments were made by using the 6.75 MeV protons from a cyclotron and the protons in the energy range from 3 to 9 MeV from a tandem Van de Graaff. The windows with and without sample-foils were rotated in front of a semiconductor detector, and the measured energy loss and the thickness of the sample foils were used to estimate the energy loss at the mean energy of protons in the samples. The analyses were made by considering the inner shell correction, Z 1 3 correction and the Bloch correction. The mean ionization potentials were derived from the data. (Kato, T.)

On the neutralization of noble gas ions in low energy ion scattering

International Nuclear Information System (INIS)

Draxler, M.

2003-04-01

The set-up ACOLISSA has been set to operation. It was thoroughly tested and found to completely fulfill the requirements for the measurement of charge integrated and of ion TOF-LEIS spectra. Charge integrated scattering spectra in LEIS exhibit a surface peak in many experimental conditions. It was shown that the appearance of this peak is due to a reduced energy width of the contribution from the surface layer and partly due to a reduced energy loss in the surface layer as compared to deeper layers. In the regime of strong multiple scattering, both reasons reflect the fact, that scattering from surface atoms occurs practically exclusively by single binary collisions, while plural and multiple scattering set in in the subsurface layers. As a consequence, only the surface layer and to some extent also the second layer will contribute to the surface peak. Experiment as well as simulation show this behavior, so that other possible reasons for the appearance of a surface peak (e.g. channeling) can safely be ruled out. At high energies, when the multiple scattering half width angle is small, surface effects are mainly caused by electronic stopping and become small, as observed in both, experiment and simulation. In this regime, the energy spectrum is well described by the single scattering spectrum. From the present thesis one can draw the following conclusions concerning the neutralization of noble gas ions at metal surfaces: below the threshold for collision induced processes (CIN, CIR) Ε Εth), P+ is governed by local processes (collision induced neutralization and collision induced reionization) and by a non-local process (Auger neutralization), and thus depends on the energy as well as on vperp. From experiments like the one presented here, where the ion energy as well as the scattering geometry are varied, the process parameters of the neutralization can uniquely be determined for any system. These findings are generally valid and reveal the relevance of different

Recent ion measurements within the modified DPF-1000U facility

Directory of Open Access Journals (Sweden)

Kwiatkowski Roch

2015-06-01

Full Text Available In this note we describe measurements of ion beams emitted along the z-axis of the DPF-1000U facility operated at 23 kV, 334 kJ, and with the initial deuterium pressure of 1.6–2 hPa. The DPF-1000U device was recently renewed and equipped with a dynamic gas-puff valve placed inside the inner electrode. The investigated ions were recorded by means of ion pinhole cameras equipped with solid state nuclear track detectors of the PM-355® (PADC type. The energy spectra of ions were determined using a Thomson spectrometer placed on the symmetry axis at a distance of 160 cm from the electrodes outlets. The ion images recorded during discharges performed under different experimental conditions show that the ion beams have a complex structure, usually in the form of a central bunch and an annular stream composed of many micro-beams. Energies of the registered deuterons have been in the range of 30–700 keV, while the fast protons (which originated from the hydrogen remnants had energies in the range of 300–850 keV.

Heavy ions reactions at GANIL energies: the use of LISE telescopic mode for the small angle measurements

International Nuclear Information System (INIS)

Bacri, C.O.

1989-01-01

The use of heavy ions at GANIL energies leads to a concentration of the reaction products in the forward direction. Measurements have to be performed at and around 0 degree and with an accuracy around one milliradian. The angular selection (after the two dipoles) is performed after a magnetic rigidity one (between the two dipoles). The double sorting does allow measurements close to the beam in magnetic rigidity and in angle. TRANSPORT calculations show that the LISE spectrometer of GANIL can be used in telescopic mode. Experiments with a 44 MeV per nucleon Argon beam on C, Al, Ni and Au targets are performed. The identification of all the detected ions allowed the obtention of angular distributions at and around 0 degree with the required accuracy. This study is completed by a theoretical approach of the thermodynamical evolution based on an extended quantal mean field theory in which a collision-like term simulates residual interaction effects [fr

Collisions of polyatomic ions with surfaces: incident energy partitioning and chemical reactions

International Nuclear Information System (INIS)

Zabka, J.; Roithova, J.; Dolejsek, Z.; Herman, Z.

2002-01-01

Collision of polyatomic ions with surfaces were investigated in ion-surface scattering experiments to obtain more information on energy partitioning in ion-surface collision and on chemical reactions at surfaces. Mass spectra, translation energy and angular distributions of product ions were measured in dependence on the incident energy and the incident angle of polyatomic projectiles. From these data distributions of energy fractions resulting in internal excitation of the projectile, translation energy of the product ions, and energy absorbed by the surface were determined. The surface investigated were a standard stainless steel surface, covered by hydrocarbons, carbon surfaces at room and elevated temperatures, and several surfaces covered by a self-assembled monolayers (C 12 -hydrocarbon SAM, C 11 -perfluorohydrocarbon SAM, and C 11 hydrocarbon with terminal -COOH group SAM). The main processes observed at collision energies of 10 - 50 eV were: neutralization of the ions at surfaces, inelastic scattering and dissociations of the projectile ions, quasi elastic scattering of the projectile ions, and chemical reactions with the surface material (usually hydrogen-atom transfer reactions). The ion survival factor was estimated to be a few percent for even-electron ions (like protonated ethanol ion, C 2 H 5 O + , CD 5 + ) and about 10 - 10 2 times lower for radical ions (like ethanol and benzene molecular ions, CD 4 + ). In the polyatomic ion -surface energy transfer experiments, the ethanol molecular ion was used as a well-characterized projectile ion. The results with most of the surfaces studied showed in the collision energy range of 13 - 32 eV that most collisions were strongly inelastic with about 6 - 8 % of the incident projectile energy transformed into internal excitation of the projectile (independent of the incident angle) and led partially to its further dissociation in a unimolecular way after the interaction with the surface. The incident energy

Mean range and energy of 28Si ions some Makrofol track detectors

International Nuclear Information System (INIS)

Shyam, S.; Mishra, R.; Tripathy, S.P.; Mawar, A.K.; Dwivedi, K.K.; Khathing, D.T.; Srivastava, A.; Avasthi, D.K.

2000-01-01

The rate of energy loss of the impinging ion as it passes through succeeding layers of the target material gives information regarding the nature of material and helps to calculate the range of the ions in a thick target in which the ions are stopped. Here the range, energy loss of 118 MeV 28 Si were measured in Makrofol-N, Makrofol-G and Makrofol-KG, using nuclear track technique. The experimental range data are compared with the theoretical values obtained from different computer codes. (author)

Tailored ion energy distributions on plasma electrodes

International Nuclear Information System (INIS)

Economou, Demetre J.

2013-01-01

As microelectronic device features continue to shrink approaching atomic dimensions, control of the ion energy distribution on the substrate during plasma etching and deposition becomes increasingly critical. The ion energy should be high enough to drive ion-assisted etching, but not too high to cause substrate damage or loss of selectivity. In many cases, a nearly monoenergetic ion energy distribution (IED) is desired to achieve highly selective etching. In this work, the author briefly reviews: (1) the fundamentals of development of the ion energy distribution in the sheath and (2) methods to control the IED on plasma electrodes. Such methods include the application of “tailored” voltage waveforms on an electrode in continuous wave plasmas, or the application of synchronous bias on a “boundary electrode” during a specified time window in the afterglow of pulsed plasmas

Some general scaling rules in high energy heavy ion reactions

International Nuclear Information System (INIS)

Andersson, B.; Idh, J.; Otterlund, I.; Stenlund, E.

1988-09-01

We show, using the Fritiof model scenario that the wide variation in the number of participating nucleons tend to drown other dynamical variations in the measurables of high energy ion collisions. We propose a set if general scaling laws for inclusive distributions in which it is the mean multiplicity and the mean transverse energy from each source which are the measurables in the interactions. (authors)

Ion thermal conductivity and convective energy transport in JET hot-ion regimes and H-modes

International Nuclear Information System (INIS)

Tibone, F.; Balet, B.; Cordey, J.G.

1989-01-01

Local transport in a recent series of JET experiments has been studied using interpretive codes. Auxiliary heating, mainly via neutral beam injection, was applied on low-density target plasmas confined in the double-null X-point configuration. This has produced two-component plasmas with high ion temperature and neutron yield and, above a threshold density, H-modes characterised by peak density and power deposition profiles. H-mode confinement was also obtained for the first time with 25 MW auxiliary power, of which 10 MW was from ion cyclotron resonance heating. We have used profile measurements of electron temperature T e from electron cyclotron emission and LIDAR Thomson scattering, ion temperature T i from charge-exchange recombination spectroscopy (during NBI), electron density n e from LIDAR and Abel-inverted interferometer measurements. Only sparse information is, however, available to date concerning radial profiles of effective ionic charge and radiation losses. Deuterium depletion due to high impurity levels is an important effect in these discharges, and our interpretation of thermal ion energy content, neutron yield and ion particle fluxes needs to be confirmed using measured Z eff -profiles. (author) 4 refs., 4 figs

Origin of energetic ions in the polar cusp inferred from ion composition measurements by the Viking satellite

Directory of Open Access Journals (Sweden)

G. Kremser

Full Text Available The magnetospheric ion composition spectrometer MICS on the Swedish Viking satellite provided measurements of the ion composition in the energy range 10.1 keV/eleqE/Qleq326.0 keV/e. Data obtained during orbit 842 were used to investigate the ion distribution in the northern polar cusp and its vicinity. The satellite traversed the outer ring current, boundary region, cusp proper and plasma mantle during its poleward movement. H⁺ and He⁺⁺ ions were encountered in all of these regions. He⁺ ions were present only in the ring current. The number of O⁺ and O⁺⁺ ions was very small. Heavy high-charge state ions typical for the solar wind were observed for the first time, most of them in the poleward part of the boundary region and in the cusp proper. The H⁺ ions exhibited two periods with high intensities. One of them, called the BR/CP event, appeared at energies up to 50 keV. It started at the equatorward limit of the boundary region and continued into the cusp proper. Energy spectra indicate a ring current origin for the BR/CP event. Pitch angle distributions show downward streaming of H⁺ ions at its equatorward limit and upward streaming on the poleward side. This event is interpreted as the result of pitch angle scattering of ring current ions by fluctuations in the magnetopause current layer in combination with poleward convection. The other of the two periods with high H⁺ ion intensities, called the accelerated ion event, was superimposed on the BR/CP event. It was restricted to energies leq15 keV and occurred in the poleward part of the boundary region. This event is regarded as the high-energy tail of magnetosheath ions that were accelerated while penetrating into the magnetosphere. The cusp region thus contains ions of magnetospheric as well as of magnetosheath origin. The appearance of the ions depends, in addition to the ion source, on the

Ion energy loss at maximum stopping power in a laser-generated plasma

International Nuclear Information System (INIS)

Cayzac, W.

2013-01-01

In the frame of this thesis, a new experimental setup for the measurement of the energy loss of carbon ions at maximum stopping power in a hot laser-generated plasma has been developed and successfully tested. In this parameter range where the projectile velocity is of the same order of magnitude as the thermal velocity of the plasma free electrons, large uncertainties of up to 50% are present in the stopping-power description. To date, no experimental data are available to perform a theory benchmarking. Testing the different stopping theories is yet essential for inertial confinement fusion and in particular for the understanding of the alpha-particle heating of the thermonuclear fuel. Here, for the first time, precise measurements were carried out in a reproducible and entirely characterized beam-plasma configuration. It involved a nearly fully-stripped ion beam probing a homogeneous fully-ionized plasma. This plasma was generated by irradiating a thin carbon foil with two high-energy laser beams and features a maximum electron temperature of 200 eV. The plasma conditions were simulated with a two-dimensional radiative hydrodynamic code, while the ion-beam charge-state distribution was predicted by means of a Monte-Carlo code describing the charge-exchange processes of projectile ions in plasma. To probe at maximum stopping power, high-frequency pulsed ion bunches were decelerated to an energy of 0.5 MeV per nucleon. The ion energy loss was determined by a time-of-flight measurement using a specifically developed chemical-vapor-deposition diamond detector that was screened against any plasma radiation. A first experimental campaign was carried out using this newly developed platform, in which a precision better than 200 keV on the energy loss was reached. This allowed, via the knowledge of the plasma and of the beam parameters, to reliably test several stopping theories, either based on perturbation theory or on a nonlinear T-Matrix formalism. A preliminary

Measurements of secondary neutrons producted from thick targets bombarded by heavy ions

Energy Technology Data Exchange (ETDEWEB)

Kurosawa, T.; Nakamura, T. [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center; Nakao, N.; Shibata, T.; Uwamino, Y.; Nakanishi, N.; Fukumura, A.; Kumamoto, Y.

1997-03-01

We measured neutron angular and energy distributions from high energy heavy ions stopping in targets of carbon, aluminum, copper and lead at HIMAC. These spectra are much harder for the lighter target nucleus like carbon. This means that the momentum transfer in the forward direction from heavy ion beam to lighter nuclei is much higher than that to heavier nuclei. (author)

An electron cyclotron resonance ion source based low energy ion beam platform

International Nuclear Information System (INIS)

Sun, L. T.; Shang, Y.; Ma, B. H.; Zhang, X. Z.; Feng, Y. C.; Li, X. X.; Wang, H.; Guo, X. H.; Song, M. T.; Zhao, H. Y.; Zhang, Z. M.; Zhao, H. W.; Xie, D. Z.

2008-01-01

To satisfy the requirements of surface and atomic physics study in the field of low energy multiple charge state ion incident experiments, a low energy (10 eV/q-20 keV/q) ion beam platform is under design at IMP. A simple test bench has been set up to test the ion beam deceleration systems. Considering virtues such as structure simplicity, easy handling, compactness, cost saving, etc., an all-permanent magnet ECRIS LAPECR1 [Lanzhou all-permanent magnet electron cyclotron resonance (ECR) ion source No. 1] working at 14.5 GHz has been adopted to produce intense medium and low charge state ion beams. LAPECR1 source has already been ignited. Some intense low charge state ion beams have been produced on it, but the first test also reveals that many problems are existing on the ion beam transmission line. The ion beam transmission mismatches result in the depressed performance of LAPECR1, which will be discussed in this paper. To obtain ultralow energy ion beam, after being analyzed by a double-focusing analyzer magnet, the selected ion beam will be further decelerated by two afocal deceleration lens systems, which is still under design. This design has taken into consideration both ions slowing down and also ion beam focusing. In this paper, the conceptual design of deceleration system will be discussed

An electron cyclotron resonance ion source based low energy ion beam platform.

Science.gov (United States)

Sun, L T; Shang, Y; Ma, B H; Zhang, X Z; Feng, Y C; Li, X X; Wang, H; Guo, X H; Song, M T; Zhao, H Y; Zhang, Z M; Zhao, H W; Xie, D Z

2008-02-01

To satisfy the requirements of surface and atomic physics study in the field of low energy multiple charge state ion incident experiments, a low energy (10 eV/q-20 keV/q) ion beam platform is under design at IMP. A simple test bench has been set up to test the ion beam deceleration systems. Considering virtues such as structure simplicity, easy handling, compactness, cost saving, etc., an all-permanent magnet ECRIS LAPECR1 [Lanzhou all-permanent magnet electron cyclotron resonance (ECR) ion source No. 1] working at 14.5 GHz has been adopted to produce intense medium and low charge state ion beams. LAPECR1 source has already been ignited. Some intense low charge state ion beams have been produced on it, but the first test also reveals that many problems are existing on the ion beam transmission line. The ion beam transmission mismatches result in the depressed performance of LAPECR1, which will be discussed in this paper. To obtain ultralow energy ion beam, after being analyzed by a double-focusing analyzer magnet, the selected ion beam will be further decelerated by two afocal deceleration lens systems, which is still under design. This design has taken into consideration both ions slowing down and also ion beam focusing. In this paper, the conceptual design of deceleration system will be discussed.

Mean excitation energies for molecular ions

Energy Technology Data Exchange (ETDEWEB)

Jensen, Phillip W.K.; Sauer, Stephan P.A. [Department of Chemistry, University of Copenhagen, Copenhagen (Denmark); Oddershede, Jens [Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Odense (Denmark); Quantum Theory Project, Departments of Physics and Chemistry, University of Florida, Gainesville, FL (United States); Sabin, John R., E-mail: sabin@qtp.ufl.edu [Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Odense (Denmark); Quantum Theory Project, Departments of Physics and Chemistry, University of Florida, Gainesville, FL (United States)

2017-03-01

The essential material constant that determines the bulk of the stopping power of high energy projectiles, the mean excitation energy, is calculated for a range of smaller molecular ions using the RPA method. It is demonstrated that the mean excitation energy of both molecules and atoms increase with ionic charge. However, while the mean excitation energies of atoms also increase with atomic number, the opposite is the case for mean excitation energies for molecules and molecular ions. The origin of these effects is explained by considering the spectral representation of the excited state contributing to the mean excitation energy.

Measurement of water decomposition products after the irradiation with high-energy heavy-ion beams

International Nuclear Information System (INIS)

Katsumura, Y.; Yamashita, S.; Muroya, Y.; Lin, M.; Miyazaki, T.; Kudo, H.; Murakami, T.

2005-01-01

We measured the G-values of water decomposition products produced by high-energy heavy-ion beams. It was found that the evaluated yields are consistent with reported ones. In other words, with the increase of LET, the radical yields decrease, and the molecular yields increase and tend to level off. But the evaluated yields are slightly higher than reported values. So we have started two trials. One is to check the values with experiment again, and the other is to explain the difference between the yields by using the spur diffusion model. In order to explain the values quantitatively, the spur diffusion model has been applied and track structure has been investigated. (author)

Comparison of biomolecule desorption yields for low and high energy primary ions

International Nuclear Information System (INIS)

Kamensky, I.; Hakansson, P.; Sundqvist, B.; McNeal, C.J.; MacFarlane, R.

1982-01-01

Ion induced desorption yields of molecular ions from samples of cesium iodide, glycylglycine, ergosterol, bleomycin and a trinucleoside diphosphate have been studied using primary beams of 54 MeV 63 Cu 9+ and 3 keV 133 Cs + . Mass analysis was performed with a time-of-flight technique. Each sample was studied with the same spectrometer for both low and high energy primary ions and without opening of the vacuum chamber in between the measurements. The results show that fast heavy ions give larger yields for all samples studied and that the yield ratios for high to low energy desorption increase with the mass of the sample molecule. (orig.)

An energy-filtering device coupled to a quadrupole mass spectrometer for soft-landing molecular ions on surfaces with controlled energy

Energy Technology Data Exchange (ETDEWEB)

Bodin, A.; Laloo, R.; Abeilhou, P.; Guiraud, L.; Gauthier, S.; Martrou, D. [Nanosciences Group, CEMES, CNRS UPR 8011 and University Toulouse III - Paul Sabatier, 29 rue Jeanne Marvig, BP94347, F-31055 Toulouse Cedex 4 (France)

2013-09-15

We have developed an energy-filtering device coupled to a quadrupole mass spectrometer to deposit ionized molecules on surfaces with controlled energy in ultra high vacuum environment. Extensive numerical simulations as well as direct measurements show that the ion beam flying out of a quadrupole exhibits a high-energy tail decreasing slowly up to several hundred eV. This energy distribution renders impossible any direct soft-landing deposition of molecular ions. To remove this high-energy tail by energy filtering, a 127° electrostatic sector and a specific triplet lenses were designed and added after the last quadrupole of a triple quadrupole mass spectrometer. The results obtained with this energy-filtering device show clearly the elimination of the high-energy tail. The ion beam that impinges on the sample surface satisfies now the soft-landing criterion for molecular ions, opening new research opportunities in the numerous scientific domains involving charges adsorbed on insulating surfaces.

Damage of copper by low energy xenon ions

International Nuclear Information System (INIS)

Babad-Zakhryapin, A.A.; Popenko, V.A.

1988-01-01

Changes in the copper crystal structure bombarded by xenon ions with 30-150 eV energy are studied. Foils of MOb copper mark, 10 mm in diameter and 100 μm thickness, are irradiated. The initial specimens are annealed in vacuum during 1 h at 900 K temperature. The specimens are bombarded by xenon ions in a water-cooled holder. A TE-O type accelerator serves as a xenon ion source. The ion energy varies within 30 to 150 eV range. The ion flux density is 8x10 16 ion/(cm 2 xs). It is shown that crystal structure variations at deep depths are observed not only at high (>1 keV), but at low ion energies down to several dozens of electronvolt as well. The crystal structure variation on copper irradiation by xenon ions with 30-150 eV energy is followed by formation of defects like dislocation loops, point defects in the irradiated target bulk

Sub-LET Threshold SEE Cross Section Dependency with Ion Energy

CERN Document Server

Garcia Alia, Ruben; Brandenburg, Sytze; Brugger, Markus; Daly, Eamonn; Ferlet-Cavrois, Veronique; Gaillard, Remi; Hoeffgen, Stefan; Menicucci, Alessandra; Metzger, Stefan; Zadeh, Ali; Muschitiello, Michele; Noordeh, Emil; Santin, Giovanni; CERN. Geneva. ATS Department

2015-01-01

This study focuses on the ion species and energy dependence of the heavy ion SEE cross section in the sub-let threshold region through a set of experimental data. In addition, a Monte Carlo based model is introduced and applied, showing a good agreement with the data in the several hundred MeV/n range while evidencing large discrepancies with the measurements in the 10-30 MeV/n interval, notably for the NE ion. Such discrepancies are carefully analysed and discussed.

Development of an energy analyzer as diagnostic of beam-generated plasma in negative ion beam systems

Science.gov (United States)

Sartori, E.; Carozzi, G.; Veltri, P.; Spolaore, M.; Cavazzana, R.; Antoni, V.; Serianni, G.

2017-08-01

The measurement of the plasma potential and the energy spectrum of secondary particles in the drift region of a negative ion beam offers an insight into beam-induced plasma formation and beam transport in low pressure gasses. Plasma formation in negative-ion beam systems, and the characteristics of such a plasma are of interest especially for space charge compensation, plasma formation in neutralizers, and the development of improved schemes of beam-induced plasma neutralisers for future fusion devices. All these aspects have direct implications in the ITER Heating Neutral Beam and the operation of the prototypes, SPIDER and MITICA, and also have important role in the conceptual studies for NBI systems of DEMO, while at present experimental data are lacking. In this paper we present the design and development of an ion energy analyzer to measure the beam plasma formation and space charge compensation in negative ion beams. The diagnostic is a retarding field energy analyzer (RFEA), and will measure the transverse energy spectra of plasma molecular ions. The calculations that supported the design are reported, and a method to interpret the measurements in negative ion beam systems is also proposed. Finally, the experimental results of the first test in a magnetron plasma are presented.

The stopping power and energy straggling of the energetic C and O ions in polyimide

Energy Technology Data Exchange (ETDEWEB)

Mikšová, R., E-mail: miksova@ujf.cas.cz [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v.i, 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Macková, A. [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v.i, 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Slepička, P. [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic)

2016-03-15

The stopping power and energy straggling of {sup 12}C{sup n+} and {sup 16}O{sup n+} heavy ions in the energy range 5.3–8.0 MeV in 8 μm thick polyimide (PI) foil were measured by means of an indirect transmission method using a half-covered a PIPS detector. Ions scattered from thin gold layer, under the scattering angle 150° were detected and the spectrum of ions penetrating the PI foil and without foil was recorded. The values of the experimentally determined stopping powers were compared to the calculated data by SRIM-2013 and MSTAR codes. Measured data were in good agreement with data calculated by SRIM-2013, especially for C ions was observed better agreement than for O ions. The energy straggling was determined and compared to those calculated by using Bohr’s, Bethe–Livingston and Yang models. The measured energy straggling values in the PI foil was corrected for foil roughness and thickness inhomogeneity determined from AFM. Bethe–Livingston predicting formula has been modified to make it appropriate for thicker targets. The energy straggling determined in our experiment was obtained higher than Bohr’s predicted value; the predictions by Yang are in good agreement with our experiment. Bethe–Livingston formulation of the energy straggling shows better agreement with the experimental data after the modified formula implementation which assumes that the thick target was consisted to be composed of n-number of thin layers. Influence of the charge-exchange phenomena to the energy straggling of C and O ions in PI was discussed.

Measurement of fluences and energies of D+ emitted from the plasma focus in capacitor bank energy interval of 1-20 kJ

International Nuclear Information System (INIS)

Antanasijevic, R.; Sevic, D.; Zaric, A.; Lakicevic, I.; Popovic, S.; Vukovic, J.; Konjevic, Dj.; Puric, J.; Cuk, M.

1993-01-01

Diagnostics of D + ions emitted from the D-plasma focus (PF) have been performed with CR-39 and CA 80-15 detectors. Fluences and energies of D + ions were measured for the capacitor bank energy range of 1-20 kJ. Angular distribution of D + was measured usign a pin hole camera placed at different positions in PF chamber. Energy of D + ions was estimated by diameters measurement of D + -tracks. Incident angle was 90 o . (Author)

Live cell imaging combined with high-energy single-ion microbeam

Energy Technology Data Exchange (ETDEWEB)

Guo, Na; Du, Guanghua, E-mail: gh-du@impcas.ac.cn; Liu, Wenjing; Wu, Ruqun; Wei, Junzhe [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Guo, Jinlong [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Northwest Normal University, Lanzhou (China); Chen, Hao [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Institute of Nuclear Science and Technology, University of Lanzhou, Lanzhou (China)

2016-03-15

DNA strand breaks can lead to cell carcinogenesis or cell death if not repaired rapidly and efficiently. An online live cell imaging system was established at the high energy microbeam facility at the Institute of Modern Physics to study early and fast cellular response to DNA damage after high linear energy transfer ion radiation. The HT1080 cells expressing XRCC1-RFP were irradiated with single high energy nickel ions, and time-lapse images of the irradiated cells were obtained online. The live cell imaging analysis shows that strand-break repair protein XRCC1 was recruited to the ion hit position within 20 s in the cells and formed bright foci in the cell nucleus. The fast recruitment of XRCC1 at the ion hits reached a maximum at about 200 s post-irradiation and then was followed by a slower release into the nucleoplasm. The measured dual-exponential kinetics of XRCC1 protein are consistent with the proposed consecutive reaction model, and the measurements obtained that the reaction rate constant of the XRCC1 recruitment to DNA strand break is 1.2 × 10{sup −3} s{sup −1} and the reaction rate constant of the XRCC1 release from the break-XRCC1 complex is 1.2 × 10{sup −2} s{sup −1}.

Live cell imaging combined with high-energy single-ion microbeam

International Nuclear Information System (INIS)

Guo, Na; Du, Guanghua; Liu, Wenjing; Wu, Ruqun; Wei, Junzhe; Guo, Jinlong; Chen, Hao

2016-01-01

DNA strand breaks can lead to cell carcinogenesis or cell death if not repaired rapidly and efficiently. An online live cell imaging system was established at the high energy microbeam facility at the Institute of Modern Physics to study early and fast cellular response to DNA damage after high linear energy transfer ion radiation. The HT1080 cells expressing XRCC1-RFP were irradiated with single high energy nickel ions, and time-lapse images of the irradiated cells were obtained online. The live cell imaging analysis shows that strand-break repair protein XRCC1 was recruited to the ion hit position within 20 s in the cells and formed bright foci in the cell nucleus. The fast recruitment of XRCC1 at the ion hits reached a maximum at about 200 s post-irradiation and then was followed by a slower release into the nucleoplasm. The measured dual-exponential kinetics of XRCC1 protein are consistent with the proposed consecutive reaction model, and the measurements obtained that the reaction rate constant of the XRCC1 recruitment to DNA strand break is 1.2 × 10"−"3 s"−"1 and the reaction rate constant of the XRCC1 release from the break-XRCC1 complex is 1.2 × 10"−"2 s"−"1.

Model etch profiles for ion energy distribution functions in an inductively coupled plasma reactor

International Nuclear Information System (INIS)

Chen, W.; Abraham-Shrauner, B.; Woodworth, J.R.

1999-01-01

Rectangular trench profiles are modeled with analytic etch rates determined from measured ion distribution functions. The pattern transfer step for this plasma etch is for trilayer lithography. Argon and chlorine angular ion energy distribution functions measured by a spherical collector ring analyzer are fit to a sum of drifting Maxwellian velocity distribution functions with anisotropic temperatures. The fit of the model ion distribution functions by a simulated annealing optimization procedure converges adequately for only two drifting Maxwellians. The etch rates are proportional to analytic expressions for the ion energy flux. Numerical computation of the etch profiles by integration of the characteristic equations for profile points and connection of the profiles points is efficient. copyright 1999 American Vacuum Society

Ion energy/momentum effects during ion assisted growth of niobium nitride films

Science.gov (United States)

Klingenberg, Melissa L.

The research described herein was performed to better understand and discern ion energy vs. ion momentum effects during ion beam assisted (IBAD) film growth and their effects on residual stress, crystalline structure, morphology, and composition, which influence film tribological properties. NbxN y was chosen for this research because it is a refractory material that can possess a large number of crystalline structures, and it has been found to have good tribological properties. To separate the effects of momentum transfer per arriving atom (p/a), which considers bombarding species mass, energy, and ion-to-atom transport ratio, from those of energy deposition per arriving atom (E/a), a mass independent parameter, different inert ion beams (krypton, argon, and neon) were used to create a matrix of coatings formed using similar energy deposition, but different momentum transfer and vice versa. Deposition was conducted in a research-scale IBAD system using electron beam evaporation, a radio frequency ion source, and a neutral nitrogen gas backfill. Films were characterized using x-ray diffraction, atomic force microscopy, Rutherford backscattering spectrometry, and residual stress analysis. Direct and quantifiable effects of bombardment were observed; however, energy deposition and momentum transfer effects could not be completely separated, confirming that thin film processes are complex. Complexities arose from ion-specific interactions (ion size, recoil energy, per cent reflected neutrals, Penning ionization, etc.) and chemistry effects that are not considered by the simple models. Overall, it can be stated that bombardment promoted nitride formation, nanocrystallinity, and compressive stress formation; influenced morphology (which influenced post-deposition oxygen uptake) and stress evolution; increased lattice parameter; modified crystalline phase and texture; and led to inert gas incorporation. High stress levels correlated strongly with material disorder and

Low-energy-spread ion bunches from a trapped atomic gas

NARCIS (Netherlands)

Reijnders, M.P.; Kruisbergen, van P.A.; Taban, G.; Geer, van der S.B.; Mutsaers, P.H.A.; Vredenbregt, E.J.D.; Luiten, O.J.

2009-01-01

We present time-of-flight measurements of the longitudinal energy spread of pulsed ultracold ion beams, produced by near-threshold ionization of rubidium atoms captured in a magneto-optical atom trap. Well-defined pulsed beams have been produced with energies of only 1 eV and a root-mean-square

Determining Energies and Cross Sections of Individual Ions Using Higher-Order Harmonics in Fourier Transform Charge Detection Mass Spectrometry (FT-CDMS).

Science.gov (United States)

Harper, Conner C; Elliott, Andrew G; Lin, Haw-Wei; Williams, Evan R

2018-06-02

A general method for in situ measurements of the energy of individual ions trapped and weighed using charge detection mass spectrometry (CDMS) is described. Highly charged (> 300 e), individual polyethylene glycol (PEG) ions are trapped and oscillate within an electrostatic trap, producing a time domain signal. A segmented Fourier transform (FT) of this signal yields the temporal evolution of the fundamental and harmonic frequencies of ion motion throughout the 500-ms trap time. The ratio of the fundamental frequency and second harmonic (HAR) depends on the ion energy, which is an essential parameter for measuring ion mass in CDMS. This relationship is calibrated using simulated ion signals, and the calibration is compared to the HAR values measured for PEG ion signals where the ion energy was also determined using an independent method that requires that the ions be highly charged (> 300 e). The mean error of 0.6% between the two measurements indicates that the HAR method is an accurate means of ion energy determination that does not depend on ion size or charge. The HAR is determined dynamically over the entire trapping period, making it possible to observe the change in ion energy that takes place as solvent evaporates from the ion and collisions with background gas occur. This method makes it possible to measure mass changes, either from solvent evaporation or from molecular fragmentation (MS n ), as well as the cross sections of ions measured using CDMS. Graphical Abstract.

Study of high energy ion loss during hydrogen minority heating in TFTR

International Nuclear Information System (INIS)

Park, J.; Zweben, S.J.

1994-03-01

High energy ion loss during hydrogen minority ICRF heating is measured and compared with the loss of the D-D fusion products. During H minority heating a relatively large loss of high energy ions is observed at 45 degrees below the outer midplane, with or without simultaneous NBI heating. This increase is most likely due to a loss of the minority tail protons, a possible model for this process is described

Multicavity SCRF calculation of ion hydration energies

International Nuclear Information System (INIS)

Diercksen, B.H.F.; Karelson, M.; Tamm, T.

1994-01-01

The hydration energies of the proton, hydroxyl ion, and several inorganic ions were calculated using the multicavity self-consistent reaction field (MCa SCRF) method developed for the quantum-mechanical modeling of rotationally or flexible systems in dielectric media. The ionic complexes H 3 O + (H2O) 4 , OH - (H2O) 4 , NH + 4 (H2O) 4 , and Hal - (H2O) 4 , where Hal = F, Cl, or Br, have been studied. Each complex was divided between five spheres, corresponding to the central ion and four water molecules in their first coordination sphere, respectively. Each cavity was surrounded by a polarizable medium with the dielectric permittivity of water at room temperature (80). The ionic hydration energies of ions were divided into specific and nonspecific parts. After accounting for the cavity-formation energy using scaled particle theory, good agreement between the total calculated and experimental hydration energies was obtained for all ions studied

Medium-energy electrons and heavy ions in Jupiter's magnetosphere - Effects of lower hybrid wave-particle interactions

Science.gov (United States)

Barbosa, D. D.

1986-01-01

A theory of medium-energy (about keV) electrons and heavy ions in Jupiter's magnetosphere is presented. Lower hybrid waves are generated by the combined effects of a ring instability of neutral wind pickup ions and the modified two-stream instability associated with transport of cool Iogenic plasma. The quasi-linear energy diffusion coefficient for lower hybrid wave-particle interactions is evaluated, and several solutions to the diffusion equation are given. Calculations based on measured wave properties show that the noise substantially modifies the particle distribution functions. The effects are to accelerate superthermal ions and electrons to keV energies and to thermalize the pickup ions on time scales comparable to the particle residence time. The S(2+)/S(+) ratio at medium energies is a measure of the relative contribution from Iogenic thermal plasma and neutral wind ions, and this important quantity should be determined from future measurements. The theory also predicts a preferential acceleration of heavy ions with an accleration time that scales inversely with the root of the ion mass. Electrons accelerated by the process contribute to further reionization of the neutral wind by electron impact, thus providing a possible confirmation of Alfven's critical velocity effect in the Jovian magnetosphere.

Pre-compound emission in low-energy heavy-ion interactions

Directory of Open Access Journals (Sweden)

Kumar Sharma Manoj

2017-01-01

Full Text Available Recent experimental studies have shown the presence of pre-compound emission component in heavy ion reactions at low projectile energy ranging from 4 to 7 MeV/nucleons. In earlier measurements strength of the pre-compound component has been estimated from the difference in forward-backward distributions of emitted particles. Present measurement is a part of an ongoing program on the study of reaction dynamics of heavy ion interactions at low energies aimed at investigating the effect of momentum transfer in compound, precompound, complete and incomplete fusion processes in heavy ion reactions. In the present work on the basis of momentum transfer the measurement of the recoil range distributions of heavy residues has been used to decipher the components of compound and pre-compound emission processes in the fusion of 16O projectile with 159Tb and 169Tm targets. The analysis of recoil range distribution measurements show two distinct linear momentum transfer components corresponding to pre-compound and compound nucleus processes are involved. In order to obtain the mean input angular momentum associated with compound and pre-compound emission processes, an online measurement of the spin distributions of the residues has been performed. The analysis of spin distribution indicate that the mean input angular momentum associated with pre-compound products is found to be relatively lower than that associated with compound nucleus process. The pre-compound components obtained from the present analysis are consistent with those obtained from the analysis of excitation functions.

Pre-compound emission in low-energy heavy-ion interactions

Science.gov (United States)

Sharma, Manoj Kumar; Shuaib, Mohd.; Sharma, Vijay R.; Yadav, Abhishek; Singh, Pushpendra P.; Singh, Devendra P.; Unnati; Singh, B. P.; Prasad, R.

2017-11-01

Recent experimental studies have shown the presence of pre-compound emission component in heavy ion reactions at low projectile energy ranging from 4 to 7 MeV/nucleons. In earlier measurements strength of the pre-compound component has been estimated from the difference in forward-backward distributions of emitted particles. Present measurement is a part of an ongoing program on the study of reaction dynamics of heavy ion interactions at low energies aimed at investigating the effect of momentum transfer in compound, precompound, complete and incomplete fusion processes in heavy ion reactions. In the present work on the basis of momentum transfer the measurement of the recoil range distributions of heavy residues has been used to decipher the components of compound and pre-compound emission processes in the fusion of 16O projectile with 159Tb and 169Tm targets. The analysis of recoil range distribution measurements show two distinct linear momentum transfer components corresponding to pre-compound and compound nucleus processes are involved. In order to obtain the mean input angular momentum associated with compound and pre-compound emission processes, an online measurement of the spin distributions of the residues has been performed. The analysis of spin distribution indicate that the mean input angular momentum associated with pre-compound products is found to be relatively lower than that associated with compound nucleus process. The pre-compound components obtained from the present analysis are consistent with those obtained from the analysis of excitation functions.

Fusion product measurements of the local ion thermal diffusivity in the PLT tokamak

International Nuclear Information System (INIS)

Heidbrink, W.W.; Lovberg, J.; Strachan, J.D.; Bell, R.E.

1986-03-01

Measurement of the gradient of the d-d fusion rate profile in an ohmic PLT plasma is used to deduce the gradient of the ion temperature and, thus, the local ion thermal diffusivity through an energy balance analysis. The inferred ion diffusivity is consistent with neoclassical theory

Stopping Power and Energy Straggling of Channeled He-Ions in GaN

International Nuclear Information System (INIS)

Turos, A.; Ratajczak, R.; Pagowska, K.; Nowicki, L.; Stonert, A.; Caban, P.

2011-01-01

GaN epitaxial layers are usually grown on sapphire substrates. To avoid disastrous effect of the large lattice mismatch a thin polycrystalline nucleation layer is grown at 500 o C followed by the deposition of thick GaN template at much higher temperature. Remnants of the nucleation layer were visualized by transmission electron microscopy as defect agglomeration at the GaN/sapphire interface and provide a very useful depth marker for the measurement of channeled ions stopping power. Random and aligned spectra of He ions incident at energies ranging from 1.7 to 3.7 MeV have been measured and evaluated using the Monte Carlo simulation code McChasy. Impact parameter dependent stopping power has been calculated for channeling direction and its parameters have been adjusted according to experimental data. For virgin, i.e. as grown, samples, the ratio of channeled to random stopping power is constant and amounts to 0.7 in the energy range studied. Defects produced by ion implantation largely influence the stopping power. For channeled ions the variety of possible trajectories leads to different energy loss at a given depth, thus resulting in much larger energy straggling than that for the random path. Beam energy distributions at different depths have been calculated using the McChasy code. They are significantly broader than those predicted by the Bohr formula for random direction. (author)

Energy distribution of ions produced by laser ablation of silver in vacuum

International Nuclear Information System (INIS)

Toftmann, B.; Schou, J.; Canulescu, S.

2013-01-01

The ion energy in a silver ablation plume for fluence in the range of 0.6–2.4 J cm −2 , typical for a pulsed laser deposition (PLD) experiment has been investigated. In this fluence range the ion fraction of the ablated particles becomes gradually dominant and can be utilized to characterize the ablation process. A silver target in vacuum was irradiated with a Nd:YAG laser at a wavelength of 355 nm and detailed measurements of the time-resolved angular distribution of plume ions were made. In contrast to earlier work, the beam spot was circular such that any flip-over effect of the plume is avoided. The angular energy distribution of ions in forward direction exceeds values of 500 eV, while at large angles the ion energy tail is below 100 eV. The maximum for the time-of-flight distributions agrees consistently with the prediction of Anisimov's model in the low fluence range, in which hydrodynamic motion prevails.

A high-flux low-energy hydrogen ion beam using an end-Hall ion source

NARCIS (Netherlands)

Veldhoven, J. van; Sligte, E. te; Janssen, J.P.B.

2016-01-01

Most ion sources that produce high-flux hydrogen ion beams perform best in the high energy range (keV). Alternatively, some plasma sources produce very-lowenergy ions (<< 10 eV). However, in an intermediate energy range of 10-200 eV, no hydrogen ion sources were found that produce high-flux beams.

Measurements of diameters of selectively etchable tracks produced in polymer by heavy ions

International Nuclear Information System (INIS)

Apel', P.Yu.

1981-01-01

The process of pore formation in polyethyleneterephtalate films irradiated by the 136 Xe, 84 Kr, 40 Ar ions was investigated by measuring the conductivity of the samples during etching. The diameters of the damaged tracks within which the local etching rate was larger than etching rate for non-destroyed polymer were determined. In the case of the 136 Xe ions measurements have been carried out at different ion energies [ru

Note on measuring electronic stopping of slow ions

Science.gov (United States)

Sigmund, P.; Schinner, A.

2017-11-01

Extracting stopping cross sections from energy-loss measurements requires careful consideration of the experimental geometry. Standard procedures for separating nuclear from electronic stopping treat electronic energy loss as a friction force, ignoring its dependence on impact parameter. In the present study we find that incorporating this dependence has a major effect on measured stopping cross sections, in particular for light ions at low beam energies. Calculations have been made for transmission geometry, nuclear interactions being quantified by Bohr-Williams theory of multiple scattering on the basis of a Thomas-Fermi-Molière potential, whereas electronic interactions are characterized by Firsov theory or PASS code. Differences between the full and the restricted stopping cross section depend on target thickness and opening angle of the detector and need to be taken into account in comparisons with theory as well as in applications of stopping data. It follows that the reciprocity principle can be violated when checked on restricted instead of full electronic stopping cross sections. Finally, we assert that a seeming gas-solid difference in stopping of low-energy ions is actually a metal-insulator difference. In comparisons with experimental results we mostly consider proton data, where nuclear stopping is only a minor perturbation.

A Thomson-type mass and energy spectrometer for characterizing ion energy distributions in a coaxial plasma gun operating in a gas-puff mode

Energy Technology Data Exchange (ETDEWEB)

Rieker, G. B.; Poehlmann, F. R.; Cappelli, M. A. [High Temperature Gasdynamics Laboratory, Stanford University, Stanford, California 94305 (United States)

2013-07-15

Measurements of ion energy distribution are performed in the accelerated plasma of a coaxial electromagnetic plasma gun operating in a gas-puff mode at relatively low discharge energy (900 J) and discharge potential (4 kV). The measurements are made using a Thomson-type mass and energy spectrometer with a gated microchannel plate and phosphor screen as the ion sensor. The parabolic ion trajectories are captured from the sensor screen with an intensified charge-coupled detector camera. The spectrometer was designed and calibrated using the Geant4 toolkit, accounting for the effects on the ion trajectories of spatial non-uniformities in the spectrometer magnetic and electric fields. Results for hydrogen gas puffs indicate the existence of a class of accelerated protons with energies well above the coaxial discharge potential (up to 24 keV). The Thomson analyzer confirms the presence of impurities of copper and iron, also of relatively high energies, which are likely erosion or sputter products from plasma-electrode interactions.

A Thomson-type mass and energy spectrometer for characterizing ion energy distributions in a coaxial plasma gun operating in a gas-puff mode

International Nuclear Information System (INIS)

Rieker, G. B.; Poehlmann, F. R.; Cappelli, M. A.

2013-01-01

Measurements of ion energy distribution are performed in the accelerated plasma of a coaxial electromagnetic plasma gun operating in a gas-puff mode at relatively low discharge energy (900 J) and discharge potential (4 kV). The measurements are made using a Thomson-type mass and energy spectrometer with a gated microchannel plate and phosphor screen as the ion sensor. The parabolic ion trajectories are captured from the sensor screen with an intensified charge-coupled detector camera. The spectrometer was designed and calibrated using the Geant4 toolkit, accounting for the effects on the ion trajectories of spatial non-uniformities in the spectrometer magnetic and electric fields. Results for hydrogen gas puffs indicate the existence of a class of accelerated protons with energies well above the coaxial discharge potential (up to 24 keV). The Thomson analyzer confirms the presence of impurities of copper and iron, also of relatively high energies, which are likely erosion or sputter products from plasma-electrode interactions

A Thomson-type mass and energy spectrometer for characterizing ion energy distributions in a coaxial plasma gun operating in a gas-puff mode

Science.gov (United States)

Rieker, G. B.; Poehlmann, F. R.; Cappelli, M. A.

2013-07-01

Measurements of ion energy distribution are performed in the accelerated plasma of a coaxial electromagnetic plasma gun operating in a gas-puff mode at relatively low discharge energy (900 J) and discharge potential (4 kV). The measurements are made using a Thomson-type mass and energy spectrometer with a gated microchannel plate and phosphor screen as the ion sensor. The parabolic ion trajectories are captured from the sensor screen with an intensified charge-coupled detector camera. The spectrometer was designed and calibrated using the Geant4 toolkit, accounting for the effects on the ion trajectories of spatial non-uniformities in the spectrometer magnetic and electric fields. Results for hydrogen gas puffs indicate the existence of a class of accelerated protons with energies well above the coaxial discharge potential (up to 24 keV). The Thomson analyzer confirms the presence of impurities of copper and iron, also of relatively high energies, which are likely erosion or sputter products from plasma-electrode interactions.

A Thomson-type mass and energy spectrometer for characterizing ion energy distributions in a coaxial plasma gun operating in a gas-puff mode.

Science.gov (United States)

Rieker, G B; Poehlmann, F R; Cappelli, M A

2013-07-01

Measurements of ion energy distribution are performed in the accelerated plasma of a coaxial electromagnetic plasma gun operating in a gas-puff mode at relatively low discharge energy (900 J) and discharge potential (4 kV). The measurements are made using a Thomson-type mass and energy spectrometer with a gated microchannel plate and phosphor screen as the ion sensor. The parabolic ion trajectories are captured from the sensor screen with an intensified charge-coupled detector camera. The spectrometer was designed and calibrated using the Geant4 toolkit, accounting for the effects on the ion trajectories of spatial non-uniformities in the spectrometer magnetic and electric fields. Results for hydrogen gas puffs indicate the existence of a class of accelerated protons with energies well above the coaxial discharge potential (up to 24 keV). The Thomson analyzer confirms the presence of impurities of copper and iron, also of relatively high energies, which are likely erosion or sputter products from plasma-electrode interactions.

Modelling interaction cross sections for intermediate and low energy ions

International Nuclear Information System (INIS)

Toburen, L.H.; Shinpaugh, J.L.; Justiniano, E.L.B.

2002-01-01

When charged particles slow in tissue they undergo electron capture and loss processes than can have profound effects on subsequent interaction cross sections. Although a large amount of data exists for the interaction of bare charged particles with atoms and molecules, few experiments have been reported for these 'dressed' particles. Projectile electrons contribute to an impact-parameter-dependent screening of the projectile charge that precludes straightforward scaling of energy loss cross sections from those of bare charged particles. The objective of this work is to develop an analytical model for the energy-loss-dependent effects of screening on differential ionisation cross sections that can be used in track structure calculations for high LET ions. As a first step a model of differential ionisation cross sections for bare ions has been combined with a simple screening model to explore cross sections for intermediate and low energy dressed ions in collisions with atomic and molecular gas targets. The model is described briefly and preliminary results compared to measured electron energy spectra. (author)

Stopping powers of gases for ions of energy below 200 keV

International Nuclear Information System (INIS)

Fukuda, Akira

1978-01-01

There has been renewed interest in the stopping power of matters for ions in low energy region. But there is not an established theory in this energy region, and experimental data did not coincide with the curves in some data books. Therefore, precise experimental measurement is still necessary. In present neutron dosimetry, tissues are the object of measurement of absorbed dose. In this experiment, it was intended to use tissue equivalent gas as a target gas. In the experimental apparatus, ions come from the Cockcroft-Walton accelerator are applied to the cell, in which the target gas is admitted from gas source. Gas in the cell is observed with the electrostatic energy analyzer. Stopping power is calculated from the results of energy loss measurement. In this report, only the preliminary results are shown. The tissue equivalent gas is composed of CH 4 , CO 2 and N 2 , each percentage is 64.95, 32.2 and 2.85, respectively. It seems that the stopping powers of noble gases will be useful for the developments of the theory, and the stopping power for He + ions was measured. The results are shown in a figure, and the errors were estimated to be less than 1.5%. At the end of the report, some discussions among a few persons are added. (Wakatsuki, Y.)

Ion kinetic energy distribution in a pulsed vacuum arc with a straight magnetic filter

International Nuclear Information System (INIS)

Giuliani, L; Grondona, D; Kelly, H; Minotti, F

2008-01-01

In vacuum arcs of interest for film deposition the ion kinetic energy is of importance because it influences the coating properties. In this kind of discharge, the ions come out from the cathode spots with a high kinetic energy (20-150 eV). In the present work, we present measurements of vacuum arc ion energy distributions in a pulsed vacuum arc with a straight magnetic filter. A retarding field analyser (RFA) was used to perform the measurements that were carried out with a variable magnetic field strength (of the order of 10 mT). Since the interpretation of the results obtained from the RFA lies in the knowledge of the plasma and floating potential values, we have employed also Langmuir probes for determining those quantities. The obtained results for the ion kinetic energy are similar to those reported by other authors, but they were also found to be independent of the magnetic field strength. The electron temperature was also found to be independent of the magnetic field strength and of the axial position along the filter, indicating the absence of collisions.

Status of Charge Exchange Cross Section Measurements for Highly Charged Ions on Atomic Hydrogen

Science.gov (United States)

Draganic, I. N.; Havener, C. C.; Schultz, D. R.; Seely, D. G.; Schultz, P. C.

2011-05-01

Total cross sections of charge exchange (CX) for C5+, N6+, and O7+ ions on ground state atomic hydrogen are measured in an extended collision energy range of 1 - 20,000 eV/u. Absolute CX measurements are performed using an improved merged-beams technique with intense highly charged ion beams extracted from a 14.5 GHz ECR ion source mounted on a high voltage platform. In order to improve the problematic H+ signal collection for these exoergic CX collisions at low relative energies, a new double focusing electrostatic analyzer was installed. Experimental CX data are in good agreement with all previous H-oven relative measurements at higher collision energies. We compare our results with the most recent molecular orbital close-coupling (MOCC) and atomic orbital close-coupling (AOCC) theoretical calculations. Work supported by the NASA Solar & Heliospheric Physics Program NNH07ZDA001N, the Office of Fusion Energy Sciences and the Division of Chemical Sciences, Geosciences, and Biosciences, and the Office of Basic Energy Sciences of the U.S. DoE.

Surface-conductivity enhancement of PMMA by keV-energy metal-ion implantation

International Nuclear Information System (INIS)

Bannister, M.E.; Hijazi, H.; Meyer, H.M.; Cianciolo, V.; Meyer, F.W.

2014-01-01

An experiment has been proposed to measure the neutron electric dipole moment (nEDM) with high precision at the Oak Ridge National Laboratory (ORNL) Spallation Neutron Source. One of the requirements of this experiment is the development of PMMA (Lucite) material with a sufficiently conductive surface to permit its use as a high-voltage electrode while immersed in liquid He. At the ORNL Multicharged Ion Research Facility, an R and D activity is under way to achieve suitable surface conductivity in poly-methyl methacrylate (PMMA) using metal ion implantation. The metal implantation is performed using an electron-cyclotron-resonance (ECR) ion source and a recently developed beam line deceleration module that is capable of providing high flux beams for implantation at energies as low as a few tens of eV. The latter is essential for reaching implantation fluences exceeding 1 × 10 16 cm −2 , where typical percolation thresholds in polymers have been reported. In this contribution, we report results on initial implantation of Lucite by Ti and W beams with keV energies to average fluences in the range 0.5–6.2 × 10 16 cm −2 . Initial measurements of surface-resistivity changes are reported as function of implantation fluence, energy, and sample temperature. We also report X-ray photoelectron spectroscopy (XPS) surface and depth profiling measurements of the ion implanted samples, to identify possible correlations between the near surface and depth resolved implanted W concentrations and the measured surface resistivities

Rechargeable dual-metal-ion batteries for advanced energy storage.

Science.gov (United States)

Yao, Hu-Rong; You, Ya; Yin, Ya-Xia; Wan, Li-Jun; Guo, Yu-Guo

2016-04-14

Energy storage devices are more important today than any time before in human history due to the increasing demand for clean and sustainable energy. Rechargeable batteries are emerging as the most efficient energy storage technology for a wide range of portable devices, grids and electronic vehicles. Future generations of batteries are required to have high gravimetric and volumetric energy, high power density, low price, long cycle life, high safety and low self-discharge properties. However, it is quite challenging to achieve the above properties simultaneously in state-of-the-art single metal ion batteries (e.g. Li-ion batteries, Na-ion batteries and Mg-ion batteries). In this contribution, hybrid-ion batteries in which various metal ions simultaneously engage to store energy are shown to provide a new perspective towards advanced energy storage: by connecting the respective advantages of different metal ion batteries they have recently attracted widespread attention due to their novel performances. The properties of hybrid-ion batteries are not simply the superposition of the performances of single ion batteries. To enable a distinct description, we only focus on dual-metal-ion batteries in this article, for which the design and the benefits are briefly discussed. We enumerate some new results about dual-metal-ion batteries and demonstrate the mechanism for improving performance based on knowledge from the literature and experiments. Although the search for hybrid-ion batteries is still at an early age, we believe that this strategy would be an excellent choice for breaking the inherent disadvantages of single ion batteries in the near future.

Rapid change of ion energy distribution and floating potential at L/H transition in the JFT-2M tokamak

International Nuclear Information System (INIS)

Miura, Y.; Nagashima, K.; Okano, F.

1994-01-01

Rapid changes of the main ion energy distribution at transitions from L-to-H, H-to-L and during ELMs are studied with the time of flight neutral measurement in the JFT-2M tokamak. The change of the main ion energy distribution after sawtooth crash during an L-mode phase is also studied. The change of the ion energy distribution just after sawtooth crash is the same as that at L/H-transition. The floating potential measured in the SOL also shows the rapid jump to more positive just after the sawtooth crash (at the same time of the change of an ion energy distribution). This shows the increase of ion outflux in the SOL and might correspond to the change of the ion energy distribution. This may be the reason why most of H-modes are triggered by a sawtooth. (author)

Fragment formation in GeV-energy proton and light heavy-ion induced reactions

International Nuclear Information System (INIS)

Murakami, T.; Haga, M.; Haseno, M.

2002-01-01

We have investigated similarities and differences among the fragment formation processes in GeV-energy light-ion and light heavy-ion induced reactions. We have newly measured inclusive and exclusive energy spectra of intermediate mass fragments (3 ≤ Z ≤ 30; IMFs) for 8-GeV 16 O and 20 Ne and 12-GeV 20 Ne induced target multifragmentations (TMFs) in order to compare them with those previously measured for 8- and 12-GeV proton induced TMFs. We fond noticeable difference in their spectrum shapes and magnitudes but all of them clearly indicate the existence of sideward-peaked components, indicating fragment formations are mainly dictated not by a incident energy per nucleon but by a total energy of the projectile. (author)

Analysis of the ion energy transport in ohmic discharges in the ASDEX tokamak

International Nuclear Information System (INIS)

Simmet, E.E.; Fahrbach, H.U.; Herrmann, W.; Stroth, U.

1996-10-01

An analysis of the local ion energy transport is performed for more than one hundred well documented ohmic ASDEX discharges. These are characterized by three different confinement regimes: the linear ohmic confinement (LOC), the saturated ohmic confinement (SOC) and the improved ohmic confinement (IOC). All three are covered by this study. To identify the most important local transport mechanism of the ion heat, the ion power balance equation is analyzed. Two methods are used: straightforward calculation with experimental data only, and a comparison of measured and calculated profiles of the ion temperature and the ion heat conductivity, respectively. A discussion of the power balance shows that conductive losses dominate the ion energy transport in all ohmic discharges of ASDEX. Only inside the q=1-surface losses due to sawtooth activity play a role, while at the edge convective fluxes and CX-losses influence the ion energy transport. Both methods lead to the result that both the ion temperature and the ion heat conductivity are consistent with predictions of the neoclassical theory. Enhanced heat losses as suggested by theories eg. on the basis of η i modes can be excluded. (orig.)

Measurement of fluences and energies of D{sup +} emitted from the plasma focus in capacitor bank energy interval of 1-20 kJ

Energy Technology Data Exchange (ETDEWEB)

Antanasijevic, R.; Sevic, D.; Zaric, A.; Lakicevic, I.; Popovic, S.; Vukovic, J.; Konjevic, Dj. [Belgrade Univ. (Yugoslavia). Inst. za Fiziku; Puric, J.; Cuk, M. [Belgrade Univ. (Yugoslavia). Faculty of Physics

1993-12-31

Diagnostics of D{sup +} ions emitted from the D-plasma focus (PF) have been performed with CR-39 and CA 80-15 detectors. Fluences and energies of D{sup +} ions were measured for the capacitor bank energy range of 1-20 kJ. Angular distribution of D{sup +} was measured usign a pin hole camera placed at different positions in PF chamber. Energy of D{sup +} ions was estimated by diameters measurement of D{sup +} -tracks. Incident angle was 90{sup o}. (Author).

Energy spread in ion beam analysis

International Nuclear Information System (INIS)

Szilagyi, E.

2000-01-01

In ion beam analysis (IBA) the depth profiles are extracted from the experimentally determined energy profiles. The spectra, however, are subject to finite energy resolution of both extrinsic and intrinsic origin. Calculation of those effects such as instrumental beam, geometry and detection-related energy and angular spreads as well as energy straggling, multiple scattering and Doppler effects in the sample itself is not trivial, especially since it involves treatment of non-independent random processes. A proper account for energy spread is vital in IBA not only for correct extraction of elemental and isotopic depth profiles from the measured spectra, but already prior to data acquisition, in optimising experimental conditions to reach the required depth resolution at a certain depth. After a short review of the literature on the different energy spread contributions experimental examples are given from resonance, RBS, elastic BS and ERDA practice in which an account for energy spread contributions is essential. Some further examples illustrate extraction of structural information (roughness, pore size, etc.) from elaborated depth resolution calculation for such layer structures

Energy spread in ion beam analysis

Energy Technology Data Exchange (ETDEWEB)

Szilagyi, E. E-mail: szilagyi@rmki.kkfki.hu

2000-03-01

In ion beam analysis (IBA) the depth profiles are extracted from the experimentally determined energy profiles. The spectra, however, are subject to finite energy resolution of both extrinsic and intrinsic origin. Calculation of those effects such as instrumental beam, geometry and detection-related energy and angular spreads as well as energy straggling, multiple scattering and Doppler effects in the sample itself is not trivial, especially since it involves treatment of non-independent random processes. A proper account for energy spread is vital in IBA not only for correct extraction of elemental and isotopic depth profiles from the measured spectra, but already prior to data acquisition, in optimising experimental conditions to reach the required depth resolution at a certain depth. After a short review of the literature on the different energy spread contributions experimental examples are given from resonance, RBS, elastic BS and ERDA practice in which an account for energy spread contributions is essential. Some further examples illustrate extraction of structural information (roughness, pore size, etc.) from elaborated depth resolution calculation for such layer structures.

Probing the Martian Exosphere and Neutral Escape Using Pickup Ions Measured by MAVEN

Science.gov (United States)

Rahmati, A.; Larson, D. E.; Cravens, T.; Halekas, J. S.; Lillis, R. J.; McFadden, J. P.; Mitchell, D. L.; Thiemann, E.; Connerney, J. E. P.; Dunn, P.; DiBraccio, G. A.; Espley, J. R.; Eparvier, F. G.; Jakosky, B. M.

2016-12-01

Soon after the MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft started orbiting Mars in September 2014, the SEP (Solar Energetic Particle), SWIA (Solar Wind Ion Analyzer), and STATIC (Supra-Thermal and Thermal Ion Composition) instruments onboard the spacecraft started detecting planetary pickup ions. SEP can measure energetic (>50 keV) oxygen pickup ions, the source of which is the extended hot oxygen exosphere of Mars. Model results show that these pickup ions originate from tens of Martian radii upstream of Mars and are energized by the solar wind motional electric field as they gyrate back towards Mars. SEP is blind to pickup hydrogen, as the low energy threshold for detection of hydrogen in SEP is 20 keV; well above the maximum pickup hydrogen energy, which is four times the solar wind proton energy. SWIA and STATIC, on the other hand, can detect both pickup oxygen and pickup hydrogen with energies below 30 keV and created closer to Mars. During the times when MAVEN is outside the Martian bow shock and in the upstream undisturbed solar wind, the solar wind velocity measured by SWIA and the solar wind (or interplanetary) magnetic field measured by the MAG (magnetometer) instrument can be used to model pickup oxygen and hydrogen fluxes near Mars. Solar wind flux measurements of the SWIA instrument are used in calculating charge-exchange frequencies, and data from the EUVM (Extreme Ultraviolet Monitor) and SWEA (Solar Wind Electron Analyzer) instruments are also used in calculating photo-ionization and electron impact frequencies of neutral species in the Martian exosphere. By comparing SEP, SWIA, and STATIC measured pickup ion fluxes with model results, the Martian thermal hydrogen and hot oxygen neutral densities can be probed outside the bow shock, which would place constraints on estimates of oxygen and hydrogen neutral escape rates. We will present model-data comparisons of pickup ions measured outside the Martian bow shock. Our analysis reveals an

Ion beam studies. Part 1. The retardation of ion beams to very low energies in an implantation accelerator

International Nuclear Information System (INIS)

Freeman, J.H.; Temple, W.; Beanland, D.; Gard, G.A.

1976-02-01

The design and operation of a compact electrostatic lens for the retardation and focussing of high intensity beams of heavy ions down to energies in the range 10 to 1,000 eV is described. The use of such beams for low-energy ion implantation and for the production of uniform ion-deposited layers is outlined. The practical behaviour of the lens is shown to be in agreement with computer calculations and the theoretical model is used to delineate and explain the boundary conditions under which the focussing behaviour becomes anomalous. The calculated and measured effects of space-charge repulsion on the quality of focussing are compared and it is demonstrated that a simple retardation lens design can be effectively employed at high flux. (author)

An online low energy gaseous ion source

International Nuclear Information System (INIS)

Jin Shuoxue; Guo Liping; Peng Guoliang; Zhang Jiaolong; Yang Zheng; Li Ming; Liu Chuansheng; Ju Xin; Liu Shi

2010-01-01

The accumulation of helium and/or hydrogen in nuclear materials may cause performance deterioration of the materials. In order to provide a unique tool to investigate the He-and/or H-caused problems, such as interaction of helium with hydrogen and defects, formation of gas bubbles and its evolution, and the related effects, we designed a low energy (≤ 20 keV) cold cathode Penning ion source, which will be interfaced to a 200 kV transmission electron microscope (TEM), for monitoring continuously the evolution of micro-structure during the He + or H + ion implantation. Studies on discharge voltage-current characteristics of the ion source, and extraction and focusing of the ion beam were performed. The ion source works stably with 15-60 mA of the discharge current.Under the gas pressure of 5 x 10 -3 Pa and 1.5 x 10 -2 Pa, the discharge voltage are about 380 V and 320 V, respectively. The extracted ion current under lower gas pressure is greater than that under higher gas pressure, and it increases with the discharge current and extraction voltage. The ion lens consisting of three equal-diameter metal cylinder focus the ion beam effectively, so that the beam density at the 150 cm away from the lens exit increases by a over one order of magnitude. For ion beams of around 10 keV, the measured beam density is about 200 nA · cm -2 , which is applicable for ion implantation and in situ TEM observation for many kinds of nuclear materials. (authors)

Effects of high-energy (MeV) ion implantation of polyester films

International Nuclear Information System (INIS)

Ueno, Keiji; Matsumoto, Yasuyo; Nishimiya, Nobuyuki; Noshiro, Mitsuru; Satou, Mamoru

1991-01-01

The effects of high-energy ion beam irradiation on polyester (PET) films using a 3 MeV tandem-type ion beam accelerator were studied. O, Ni, Pt, and Au as ion species were irradiated at 10 14 -10 15 ions/cm 2 on 50 μm thick PET films. Physical properties and molecular structure changes were studied by the surface resistivity measurements and RBS. The surface resistivity decreases with an increase in irradiation dose. At 10 15 ions/cm 2 irradiation, the surface resistivity is 10 8 Ω/□. According to RBS and XPS analyses, some carbon and oxygen atoms in the PET are replaced by implanted ions and the -C=O bonds are destroyed easily by the ion beam. (orig.)

Ion-induced particle desorption in time-of-flight medium energy ion scattering

Science.gov (United States)

Lohmann, S.; Primetzhofer, D.

2018-05-01

Secondary ions emitted from solids upon ion impact are studied in a time-of-flight medium energy ion scattering (ToF-MEIS) set-up. In order to investigate characteristics of the emission processes and to evaluate the potential for surface and thin film analysis, experiments employing TiN and Al samples were conducted. The ejected ions exhibit a low initial kinetic energy of a few eV, thus, requiring a sufficiently high acceleration voltage for detection. Molecular and atomic ions of different charge states originating both from surface contaminations and the sample material are found, and relative yields of several species were determined. Experimental evidence that points towards a predominantly electronic sputtering process is presented. For emitted Ti target atoms an additional nuclear sputtering component is suggested.

Kinetic energy dissipation in heavy-ion collisions

International Nuclear Information System (INIS)

Fedotov, S.I.; Jolos, R.V.; Kartavenko, V.G.

1979-01-01

Kinetic energy dissipation mechanism is considered in deep inelastic heavy-ion collisions. It is shown that the significant part of the kinetic energy loss can be explained by the excitation of the nuclear matter multipole vibrations. The main contribution of the energy dissipation is given by the time dependent heavy-ion interaction potential renormalized due to the nuclear excitations, rather than by the velocity proportional frictional forces

Comparison of magnetosonic wave and water group ion energy densities at Comet Giacobini-Zinner

Science.gov (United States)

Staines, K.; Balogh, A.; Cowley, S. W. H.; Forster, P. M. De F.; Hynds, R. J.; Yates, T. S.; Sanderson, T. R.; Wenzel, K.-P.; Tsurutani, B. T.

1991-01-01

Measurements of the Comet Giacobini-Zinner (GZ) are presented to determine to what extent wave-particle scattering redistributed the initial pick-up energy of the ion population. Also examined is the difference between the ion thermal energy and the energy in the magnetic fields of the waves. In spite of uncertainty of about a factor of 2 noted in the pick-up and mass-loaded regions, it is shown that less than approximately 50 percent of the pick-up energy is converted into wave magnetic energy in the inbound pick-up region.

Composition and energy spectrum variations of auroral ions

International Nuclear Information System (INIS)

Lynch, J.; Leach, R.; Pulliam, D.; Scherb, F.

1977-01-01

We have detected H + ,O + , and He ++ ions with E/q up to 20 keV/charge in a hydrogen aurora over Churchill, Manitoba, during the flight of a Javelin sounding rocket on February 11, 1975, We observed several examples of different types of ion events. One type consisted of bursts of H + and O + ions which arrived simultaneously at all energies within the range of the E/q analyzer. These events were apparently of local origin (distance + ions (O + /H + approximately-greater-than30%). A second type of event consisted of bursts of enhanced H + counting rates but no O + ions. The dispersion in time of the energy spectrum was consistent with an injection and acceleration site located at about 20 R/sub E/ from the earth. An enhancement of the He ++ counting rates was associated with these events, but the He ++ data are of limited statistical significance. A third type of event, consisting of short bursts of H + ions with wide energy spreads, was observed in association with an event in which the energy of the H + ions showed time dispersion. We interpret these short H + bursts as due to ions trapped in traveling waves generated by an explosive injection of plasma in the earth's magnetotail

A silicon strip detector array for energy verification and quality assurance in heavy ion therapy.

Science.gov (United States)

Debrot, Emily; Newall, Matthew; Guatelli, Susanna; Petasecca, Marco; Matsufuji, Naruhiro; Rosenfeld, Anatoly B

2018-02-01

The measurement of depth dose profiles for range and energy verification of heavy ion beams is an important aspect of quality assurance procedures for heavy ion therapy facilities. The steep dose gradients in the Bragg peak region of these profiles require the use of detectors with high spatial resolution. The aim of this work is to characterize a one dimensional monolithic silicon detector array called the "serial Dose Magnifying Glass" (sDMG) as an independent ion beam energy and range verification system used for quality assurance conducted for ion beams used in heavy ion therapy. The sDMG detector consists of two linear arrays of 128 silicon sensitive volumes each with an effective size of 2mm × 50μm × 100μm fabricated on a p-type substrate at a pitch of 200 μm along a single axis of detection. The detector was characterized for beam energy and range verification by measuring the response of the detector when irradiated with a 290 MeV/u 12 C ion broad beam incident along the single axis of the detector embedded in a PMMA phantom. The energy of the 12 C ion beam incident on the detector and the residual energy of an ion beam incident on the phantom was determined from the measured Bragg peak position in the sDMG. Ad hoc Monte Carlo simulations of the experimental setup were also performed to give further insight into the detector response. The relative response profiles along the single axis measured with the sDMG detector were found to have good agreement between experiment and simulation with the position of the Bragg peak determined to fall within 0.2 mm or 1.1% of the range in the detector for the two cases. The energy of the beam incident on the detector was found to vary less than 1% between experiment and simulation. The beam energy incident on the phantom was determined to be (280.9 ± 0.8) MeV/u from the experimental and (280.9 ± 0.2) MeV/u from the simulated profiles. These values coincide with the expected energy of 281 MeV/u. The sDMG detector

Nanometer-size surface modification produced by single, low energy, highly charged ions

International Nuclear Information System (INIS)

Stockli, M.P.

1994-01-01

Atomically flat surfaces of insulators have been bombarded with low energy, highly charged ions to search for nanometer-size surface modifications. It is expected that the high electron deficiency of highly charged ions will capture and/or remove many of the insulator's localized electrons when impacting on an insulating surface. The resulting local electron deficiency is expected to locally disintegrate the insulator through a open-quotes Coulomb explosionclose quotes forming nanometer-size craters. Xe ions with charge states between 10+ and 45+ and kinetic energies between 0 and 10 keV/q were obtained from the KSU-CRYEBIS, a CRYogenic Electron Beam Ion Source and directed onto various insulating materials. Mica was favored as target material as atomically flat surfaces can be obtained reliably through cleaving. However, the authors observations with an atomic force microscope have shown that mica tends to defoliate locally rather than disintegrate, most likely due to the small binding forces between adjacent layers. So far the authors measurements indicate that each ion produces one blister if the charge state is sufficiently high. The blistering does not seem to depend very much on the kinetic energy of the ions

Searching for squeezed particle-antiparticle correlations in high-energy heavy-ion collisions

International Nuclear Information System (INIS)

Padula, Sandra S.; Socolowski, O. Jr.

2010-01-01

Squeezed correlations of particle-antiparticle pairs were predicted to exist if the hadron masses were modified in the hot and dense medium formed in high-energy heavy-ion collisions. Although well-established theoretically, they have not yet been observed experimentally. We suggest here a clear method to search for such a signal by analyzing the squeezed correlation functions in terms of measurable quantities. We illustrate this suggestion for simulated φφ pairs at the Relativistic Heavy Ion Collider (RHIC) energies.

Crystal Collimation with Lead Ion Beams at Injection Energy in the LHC

CERN Document Server

Rossi, Roberto; Andreassen, Arvid; Butcher, Mark; Dionisio Barreto, Cristovao Andre; Masi, Alessandro; Mirarchi, Daniele; Montesano, Simone; Lamas Garcia, Inigo; Redaelli, Stefano; Scandale, Walter; Serrano Galvez, Pablo; Rijllart, Adriaan; Valentino, Gianluca; Galluccio, Francesca; CERN. Geneva. ATS Department

2015-01-01

During this MD, performed on December 2nd 2015, bent silicon crystals were tested with ion beams for a possible usage of crystal-assisted collimation. Tests were performed at injection energy, using both horizontal and vertical crystals. Ion channeling was observed for the first time with LHC beams at the record energy of 450 GeV and the channeled beams were probed with scans performed with secondary collimators. Measurements of cleaning efficiency of a crystal-based collimation system were also performed.

Energy loss of carbon transmitted 1-MeV H2+ ions

International Nuclear Information System (INIS)

Fritz, M.; Kimura, K.; Susuki, Y.; Mannami, M.

1994-01-01

Energy losses of 1-MeV H 2 + ions passing through carbon foils of 2-8 μg/cm 2 thickness have been measured and show besides the linear increase with target thickness a 0.4 keV offset. The stopping power derived from the observed energy losses is 1.15 times as large as the sum of the stopping powers for two single H + of the same velocity. Calculations of the stopping powers for H 2 + ions and diprotons, using first Born approximation, indicate that the H 2 + ions lose the binding electron upon entrance into the foil, traverse the target as diprotons and recapture target electrons at the exit surface, a scenario also supported by the 0.4 keV offset at zero thickness. (author)

High-energy ion tail formation due to ion acoustic turbulence in the TRIAM-1 tokamak

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Kazuo; Hiraki, Naoji; Nakamura, Yukio; Itoh, Satoshi [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

1982-02-01

The two-component ion energy spectra observed in the TRIAM-1 tokamak are explained as a result of the high-energy ion tail formation due to ion acoustic turbulence driven by a toroidal current pulse for turbulent heating.

Medium-energy ion reflection from solids

CERN Document Server

Mashkova, ES

1985-01-01

``Medium-Energy Ion Reflection from Solids'' analyses the results of experimental, theoretical and computer investigations on the process of scattering of ions by solid surfaces. Surface scattering is a relatively young and rapidly developing branch of the physics of atomic collisions and the literature on this subject has rapidly grown.As the first monograph devoted specifically to surface scattering of ions, this book is directed at scientists involved in ion-solid interaction studies.

Localized subsurface modification of materials using micro-low-energy multiple ion beamlets

Directory of Open Access Journals (Sweden)

Abhishek Chowdhury

2011-12-01

Full Text Available Generation of focused multiple ion beamlets from an intense microwave plasma source is investigated for the creation of localized subsurface modification of materials. Unlike conventional single element focused ion beam (FIB systems, the plasma source is capable of providing ion beams of multiple elements. Two types of plasma electrodes (PE are employed, one with a honeycomb structure with notched apertures and another with a 5×5 array of through apertures, both attached to the plasma source and are capable of generating focused ion beamlets (50 - 100 μm diameter in a patterned manner. Measurements of ion saturation current near the PE indicate that the plasma is uniform over an area of ∼ 7 cm2, which is further confirmed by uniformity in extracted beam current through the apertures. The ion beams are applied to investigate change in electrical sheet resistance Rs of metallic thin films in a controlled manner by varying the ionic species and beam energy. Results indicate a remarkable increase in Rs with beam energy (∼ 50 % at 1 keV for Ar ions, and with ionic species (∼ 90% for Krypton ions at 0.6 keV, when 80 nm thick copper films are irradiated by ∼2 cm diameter ion beams. Ion induced surface roughness is considered as the main mechanism for this change as confirmed by atomic force microscopy (AFM measurements. Predictions for micro-beamlet induced change in Rs are discussed. The experimental results are verified using TRIM and AXCEL-INP simulations.

Measurements of inelastic collisions between homonuclear ions: Na+, K+ and Rb+

International Nuclear Information System (INIS)

Peart, B.; Forrest, R.A.; Dolder, K.

1981-01-01

Cross sections have been measured for the formation of X 2+ by collisions between X + ions (X = Na, K or Rb) with centre of mass energies between 19.3 and 87.6 keV. The results were compared with similar measurements for Li + and Cs + previously made by Peart and coworkers (J. Phys. B.; 14:1655 and 3457 (1981)), but no simple empirical or theoretical scaling law could be found to relate results for the five single-charged alkali ions. (author)

The present state and perspectives of low-energy heavy ion biology

International Nuclear Information System (INIS)

Yuan Chengling; Yu Zengliang

2004-01-01

The interaction between low-energy ions and matter has been concerned rarely comparing to that of high-energy ions. It is even more unusual to find studies of the interaction of low-energy ions and complicated organisms. However, the discovery of bioeffects induced by ion beam implantation has opened a new branch in the field of ion beam applications in the life science--Low-energy Heavy Ion Biology. The mutagenic effect of low energy heavy ions was firstly reported in 1986 in rice. Since then, a damage mechanism involved in energy absorption, mass deposition, and charge exchange has been proposed. Accumulating evidence has indicated that these three factors are key determinants in the bioeffects induced by low energy heavy ions, which has opened new opportunities for mutational breeding, gene transferring, cell modification, and cell fusion. In recent years, the ion beam implantation technique has been widely applied in many fields, and increasing research interest in the field has been seen. The authors summarize recent advances in research on the role of low-energy ions in terms of the mechanisms and applications

Ion beam sputtering of Ti: Influence of process parameters on angular and energy distribution of sputtered and backscattered particles

Energy Technology Data Exchange (ETDEWEB)

Lautenschläger, T. [Leibniz-Institute of Surface Modification, 04318 Leipzig (Germany); Feder, R., E-mail: thomas.lautenschlaeger@iom-leipzig.de [Leibniz-Institute of Surface Modification, 04318 Leipzig (Germany); Neumann, H. [Leibniz-Institute of Surface Modification, 04318 Leipzig (Germany); Rice, C.; Schubert, M. [Department of Electrical and Computer Engineering and Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0511 (United States); Bundesmann, C. [Leibniz-Institute of Surface Modification, 04318 Leipzig (Germany)

2016-10-15

Highlights: • Ion beam sputter deposition under systematic variation of process parameters. • Angular and energy distribution of secondary particles. • Interaction between incorporated and impinging process gas. • Measured data compared with simulations. - Abstract: In the present study, the influence of ion energy and geometrical parameters onto the angular and energy distribution of secondary particles for sputtering a Ti target with Ar ions is investigated. The angular distribution of the particle flux of the sputtered Ti atoms was determined by the collection method, i.e. by growing Ti films and measuring their thickness. The formal description of the particle flux can be realized by dividing it into an isotropic and an anisotropic part. The experimental data show that increasing the ion energy or decreasing the ion incidence angle lead to an increase of the isotropic part, which is in good agreement with basic sputtering theory. The energy distribution of the secondary ions was measured using an energy-selective mass spectrometer. The energy distribution of the sputtered target ions shows a maximum at an energy between 10 eV and 20 eV followed by a decay proportional to E{sup −n}, which is in principle in accordance with Thompson’s theory, followed by a high energetic tail. When the sum of incidence angle and emission angle is increased, the high-energetic tail expands to higher energies and an additional peak due to direct sputtering events may occur. In the case of backscattered primary Ar ions, a maximum at an energy between 5 eV and 10 eV appears and, depending on the scattering geometry, an additional broad peak at a higher energy due to direct scattering events is observed. The center energy of the additional structure shifts systematically to higher energies with decreasing scattering angle or increasing ion energy. The experimental results are compared to calculations based on simple elastic two-particle-interaction theory and to

Quantitative evaluation of high-energy O- ion particle flux in a DC magnetron sputter plasma with an indium-tin-oxide target

Science.gov (United States)

Suyama, Taku; Bae, Hansin; Setaka, Kenta; Ogawa, Hayato; Fukuoka, Yushi; Suzuki, Haruka; Toyoda, Hirotaka

2017-11-01

O- ion flux from the indium tin oxide (ITO) sputter target under Ar ion bombardment is quantitatively evaluated using a calorimetry method. Using a mass spectrometer with an energy analyzer, O- energy distribution is measured with spatial dependence. Directional high-energy O- ion ejected from the target surface is observed. Using a calorimetry method, localized heat flux originated from high-energy O- ion is measured. From absolute evaluation of the heat flux from O- ion, O- particle flux in order of 1018 m-2 s-1 is evaluated at a distance of 10 cm from the target. Production yield of O- ion on the ITO target by one Ar+ ion impingement at a kinetic energy of 244 eV is estimated to be 3.3  ×  10-3 as the minimum value.

An Antiproton Ion Collider (AIC) for Measuring Neutron and Proton Distributions in Stable and Radioactive Nuclei

International Nuclear Information System (INIS)

Kienle, Paul

2005-01-01

An antiproton-ion collider is proposed to independently determine mean square radii for protons and neutrons in stable and short lived nuclei by means of antiproton absorption at medium energies. The experiment makes use of the electron ion collider complex (ELISE) of the GSI FAIR project with appropriate modifications of the electron ring to store, cool and collide antiprotons of 30 MeV energy with 740A MeV energy ions.The total absorption cross-section of antiprotons by the stored ions will be measured by detecting their loss by means of the Schottky noise spectroscopy method. Cross sections for the absorption on protons and neutrons, respectively, will be studied by detection of residual nuclei with A-1 either by the Schottky method or by analysing them in recoil detectors after the first dipole stage of the NESR following the interaction zone. With a measurement of the A-1 fragment momentum distribution, one can test the momentum wave functions of the annihilated neutron and proton, respectively. Furthermore by changing the incident ion energy the tails of neutron and proton distribution can be measured.The absorption cross section is at asymptotic energies in leading order proportional to the mean square radius of the nucleus. Predicted cross sections and luminosities show that the method is applicable to nuclei with production rates of about 105 s-1 or lower, depending on the lifetime of the ions in the NESR, and for half-lives down to 1 second

High energy ion implantation for semiconductor application at Fraunhofer-AIS, Erlangen

International Nuclear Information System (INIS)

Frey, L.; Bogen, S.; Gong, L.; Jung, W.; Ryssel, H.; Gyulai, J.

1992-01-01

A new high energy ion implanter for research and development in semiconductor technology was put into operation at the Fraunhofer Institute in Erlangen. The system is used for generation of ion beams in the energy range from 100 keV to more than 6 MeV with currents up to 100 μA. A large variety of ion species can be implanted into silicon wafers with diameters up to 200 mm (with cassette-to-cassette loading up to 150 mm). The performance characteristics of the system are described with special emphasis on the end stations. In a first series of experiments, the range distributions of boron, phosphorus and arsenic in silicon have been measured for energies from 0.2 MeV to 10 MeV in order to get a data set for future applications. The profiles are compared to simulated data. First experimental results on lateral distribution of the dopant species are presented. (orig.)

The prospect for fusion energy with light ions

International Nuclear Information System (INIS)

Mehlhorn, T.A.; Adams, R.G.; Bailey, J.E.

1998-01-01

Intense ion beams may be the best option for an Inertial Fusion Energy (IFE) driver. While light ions may be the long-term pulsed power approach to IFE, the current economic climate is such that there is no urgency in developing fusion energy sources. Research on light ion beams at Sandia will be suspended at the end of this fiscal year in favor of z-pinches studying ICF target physics, high yield fusion, and stewardship issues. The authors document the status of light ion research and the understanding of the feasibility of scaling light ions to IFE

Prototype development or multi-cavity ion chamber for depth dose measurement

International Nuclear Information System (INIS)

Nayak, M.K.; Sahu, T.K.; Haridas, G.; Bandyopadhyay, Tapas; Tripathi, R.M.; Nandedkar, R.V.

2016-01-01

In high energy electron accelerators, when the electrons interact with vacuum chamber or surrounding structural material, Bremsstrahlung x-rays are produced. It is having a broad spectrum extending up to the electron energies. Dose measured as a function of depth due to electromagnetic cascade will give rise to depth dose curve. To measure the online depth dose profile in an absorber medium, when high energy electron or Bremsstrahlung is incident, a prototype Multi-Cavity Ion Chamber (MCIC) detector is developed. The paper describes the design and development of the MCIC for measurement of depth dose profile

Ion energy distributions from laser-generated plasmas at two different intensities

Science.gov (United States)

Ceccio, Giovanni; Torrisi, Lorenzo; Okamura, Masahiro; Kanesue, Takeshi; Ikeda, Shunsuke

2018-01-01

Laser-generated non-equilibrium plasmas were analyzed at Brookhaven National Laboratory (NY, USA) and MIFT Messina University (Italy). Two laser intensities of 1012 W/cm2 and 109 W/cm2, have been employed to irradiate Al and Al with Au coating targets in high vacuum conditions. Ion energy distributions were obtained using electrostatic analyzers coupled with ion collectors. Time of flight measurements were performed by changing the laser irradiation conditions. The study was carried out to provide optimum keV ions injection into post acceleration systems. Possible applications will be presented.

High yield antibiotic producing mutants of Streptomyces erythreus induced by low energy ion implantation

Science.gov (United States)

Yu, Chen; Zhixin, Lin; Zuyao, Zou; Feng, Zhang; Duo, Liu; Xianghuai, Liu; Jianzhong, Tang; Weimin, Zhu; Bo, Huang

1998-05-01

Conidia of Streptomyces erythreus, an industrial microbe, were implanted by nitrogen ions with energy of 40-60 keV and fluence from 1 × 10 11 to 5 × 10 14 ions/cm 2. The logarithm value of survival fraction had good linear relationship with the logarithm value of fluence. Some mutants with a high yield of erythromycin were induced by ion implantation. The yield increment was correlated with the implantation fluence. Compared with the mutation results induced by ultraviolet rays, mutation effects of ion implantation were obvious having higher increasing erythromycin potency and wider mutation spectrum. The spores of Bacillus subtilis were implanted by arsenic ions with energy of 100 keV. The distribution of implanted ions was measured by Rutherford Backscattering Spectrometry (RBS) and calculated in theory. The mechanism of mutation induced by ion implantation was discussed.

Magnesium aluminate planar waveguides fabricated by C-ion implantation with different energies and fluences

Energy Technology Data Exchange (ETDEWEB)

Song, Hong-Lian; Yu, Xiao-Fei; Zhang, Lian; Wang, Tie-Jun; Qiao, Mei; Zhang, Jing; Liu, Peng; Wang, Xue-Lin, E-mail: xuelinwang@sdu.edu.cn

2015-11-01

We report on MgAl{sub 2}O{sub 4} planar waveguides produced using different energies and fluences of C-ion implantation at room temperature. Based on the prism coupling method and end-face coupling measurements, light could propagate in the C-ion-implanted samples. The Raman spectra results indicate that the MgAl{sub 2}O{sub 4} crystal lattice was damaged during the multi-energy C implantation process, whereas the absorption spectra were hardly affected by the C-ion implantation in the visible and infrared bands.

Helicon plasma potential measurements using a heavy ion beam probe

International Nuclear Information System (INIS)

P. Schoch; K. Connor; J. Si

2005-01-01

A Heavy Ion Beam Probe, HIBP, has been installed on a helicon plasma device. The objective was to measure plasma fluctuations at the 13.55MHz RF frequency. This offers a unique challenge for the HIBP, because the transit time of the probing ion is long compared to the fluctuations of interest. For previous HIBPs, the transit time has been short compared to the period of the fluctuations which permits one to assume that the magnetic and electric fields are static. Modeling has shown that the diagnostic will still accurately measure the average potential. The fluctuating potential was to be detected but the absolute magnitude is difficult to determine with signal from a single point. However, modeling indicates multipoint measurements will allow one to resolve the absolute fluctuation magnitude. Work supported by DOE Grant No. DE-FG02-99ER5452985 During the funding of this grant, a helicon plasma discharge device was built and operated. A Heavy Ion Beam Probe primary system was installed and operated. A primary beam detector was installed and primary beam was detected both with and without plasma. Attempts were made to detect secondary ions using the primary beam detector, without success. Given the lack of a detectable signal, the energy analyzer of the HIBP system was never installed. It is available for installation if there is a reason to do so in the future. Analysis of the system indicated that the plasma electron temperature, estimated to be a few eV, was the likely reason for the lack of detectable secondary ions. A change of ion species to either Boron or Magnesium would greatly increase the signal, but neither of these ions have been used in a HIBP system. The ion source used in this system is made by using a charge exchange process to create a zeolite loaded with the desired ion. Attempts were made to use charge exchange to load Magnesium into a zeolite, and were not successful. It is felt that Magnesium and/or Boron zeolite sources could be created, but

Raman microprobe measurements of stress in ion implanted materials

Energy Technology Data Exchange (ETDEWEB)

Nugent, K.W.; Prawer, S.; Weiser, P.S.; Dooley, S.P. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

1993-12-31

Raman microprobe measurements of ion implanted diamond and silicon have shown significant shifts in the Raman line due to stresses in the materials. The Raman line shifts to higher energy if the stress is compressive and to lower energy for tensile stress{sup 1}. The silicon sample was implanted in a 60 {mu}m square with 2.56 x 10{sup 17} ions per square centimeter of 2 MeV Helium. This led to the formation of raised squares with the top 370mm above the original surface. In Raman studies of silicon using visible light, the depth of penetration of the laser beam into the sample is much less than one micron. It was found that the Raman line is due to the silicon overlying the damage region. The diamond sample was implanted with 2 x 10{sup 15} ions per square centimeter of 2.8 MeV carbon. It was concluded that the Raman spectrum could provide information concerning both the magnitude and the direction of stress in an ion implanted sample. It was possible in some cases to determine whether the stress direction is parallel or perpendicular to the sample surface. 1 refs., 2 figs.

Raman microprobe measurements of stress in ion implanted materials

Energy Technology Data Exchange (ETDEWEB)

Nugent, K W; Prawer, S; Weiser, P S; Dooley, S P [Melbourne Univ., Parkville, VIC (Australia). School of Physics

1994-12-31

Raman microprobe measurements of ion implanted diamond and silicon have shown significant shifts in the Raman line due to stresses in the materials. The Raman line shifts to higher energy if the stress is compressive and to lower energy for tensile stress{sup 1}. The silicon sample was implanted in a 60 {mu}m square with 2.56 x 10{sup 17} ions per square centimeter of 2 MeV Helium. This led to the formation of raised squares with the top 370mm above the original surface. In Raman studies of silicon using visible light, the depth of penetration of the laser beam into the sample is much less than one micron. It was found that the Raman line is due to the silicon overlying the damage region. The diamond sample was implanted with 2 x 10{sup 15} ions per square centimeter of 2.8 MeV carbon. It was concluded that the Raman spectrum could provide information concerning both the magnitude and the direction of stress in an ion implanted sample. It was possible in some cases to determine whether the stress direction is parallel or perpendicular to the sample surface. 1 refs., 2 figs.

STIM with energy loss contrast: An imaging modality unique to MeV ions

International Nuclear Information System (INIS)

Lefevre, H.W.; Schofield, R.M.S.; Bench, G.S.; Legge, G.J.F.

1991-01-01

Scanning transmission ion microscopy (STIM) through measurement of energy loss of individual ions is a quantitative imaging technique with several unique capabilities. The uniqueness derives conjointly from the large penetration with small scattering of MeV ions in low-Z specimens, from the simple relationship between energy loss and projected or areal density, and from the almost 100% efficiency with which one obtains pixel data from individual ions. Since contrast is in energy loss and not in numbers of events, the statistics of energy loss straggling affects the image but the statistics of counting does not. Small scattering makes it possible to observe details within transparent specimens. High efficiency makes it possible to collect large data sets for computed tomography, stereo, or high-definition imaging with a small radiation dose. High efficiency allows one to minimize aberrations by use of small apertures, to achieve good precision in the determination of areal density, or even to image live biological specimens in air since only one or a few ions per pixel are required. This paper includes a bibliography on STIM with MeV ions, it discusses the accuracy that one can achieve in the areal density coloring of a pixel with data from one or a few ions, and it supplements that review with recent examples from the Melbourne and the Eugene microprobes. (orig.)

Measurement of secondary radiation during ion beam therapy with the pixel detector Timepix

Science.gov (United States)

Martišíková, Mária; Jakubek, Jan; Granja, Carlos; Hartmann, Bernadette; Opálka, Lukáš; Pospíšil, Stanislav; Jäkel, Oliver

2011-11-01

In ion beam therapy the finite range of the ion beams in tissue and the presence of the Bragg-peak are exploited. Unpredictable changes in the patient`s condition can alter the range of the ion beam in the body. Therefore it is desired to verify the actual ion range during the treatment, preferably in a non-invasive way. Positron emission tomography (PET) has been used successfully to monitor the applied dose distributions. This method however suffers from limited applicability and low detection efficiency. In order to increase the detection efficiency and to decrease the uncertainties, in this study we investigate the possibility to measure secondary charged particles emerging from the patient during irradiation. An initial experimental study to register the particle radiation coming out of a patient phantom during the therapy was performed at the Heidelberg Ion Beam Therapy Center (HIT) in Germany. A static narrowly-focused beam of carbon ions was directed into a head phantom. The emerging secondary radiation was measured with the position-sensitive Timepix detector outside of the phantom. The detector, developed by the Medipix Collaboration, consists of a silicon sensor bump bonded to a pixelated readout chip (256 × 256 pixels with 55 μm pitch). Together with the USB-based readout interface, Timepix can operate as an active nuclear emulsion registering single particles online with 2D-track visualization. In this contribution we measured the signal behind the head phantom and investigated its dependence on the beam energy (corresponding to beam range in water 2-30 cm). Furthermore, the response was measured at four angles between 0 and 90 degrees. At all investigated energies some signal was registered. Its pattern corresponds to ions. Differences in the total amount of signal for different beam energies were observed. The time-structure of the signal is correlated with that of the incoming beam, showing that we register products of prompt processes. Such

Measurement of secondary radiation during ion beam therapy with the pixel detector Timepix

International Nuclear Information System (INIS)

Martišíková, Mária; Hartmann, Bernadette; Jäkel, Oliver; Jakubek, Jan; Granja, Carlos; Opálka, Lukáš; Pospíšil, Stanislav

2011-01-01

In ion beam therapy the finite range of the ion beams in tissue and the presence of the Bragg-peak are exploited. Unpredictable changes in the patient's condition can alter the range of the ion beam in the body. Therefore it is desired to verify the actual ion range during the treatment, preferably in a non-invasive way. Positron emission tomography (PET) has been used successfully to monitor the applied dose distributions. This method however suffers from limited applicability and low detection efficiency. In order to increase the detection efficiency and to decrease the uncertainties, in this study we investigate the possibility to measure secondary charged particles emerging from the patient during irradiation. An initial experimental study to register the particle radiation coming out of a patient phantom during the therapy was performed at the Heidelberg Ion Beam Therapy Center (HIT) in Germany. A static narrowly-focused beam of carbon ions was directed into a head phantom. The emerging secondary radiation was measured with the position-sensitive Timepix detector outside of the phantom. The detector, developed by the Medipix Collaboration, consists of a silicon sensor bump bonded to a pixelated readout chip (256 × 256 pixels with 55 μm pitch). Together with the USB-based readout interface, Timepix can operate as an active nuclear emulsion registering single particles online with 2D-track visualization. In this contribution we measured the signal behind the head phantom and investigated its dependence on the beam energy (corresponding to beam range in water 2–30 cm). Furthermore, the response was measured at four angles between 0 and 90 degrees. At all investigated energies some signal was registered. Its pattern corresponds to ions. Differences in the total amount of signal for different beam energies were observed. The time-structure of the signal is correlated with that of the incoming beam, showing that we register products of prompt processes. Such

Dose profile monitoring with carbon ions by means of prompt-gamma measurements

Energy Technology Data Exchange (ETDEWEB)

Testa, E. [Institut de Physique Nucleaire de Lyon, Universite de Lyon, F-69003 Lyon, Universite Lyon 1 and IN2P3/CNRS, UMR 5822, F-69622 Villeurbanne (France)], E-mail: e.testa@ipnl.in2p3.fr; Bajard, M.; Chevallier, M.; Dauvergne, D.; Le Foulher, F. [Institut de Physique Nucleaire de Lyon, Universite de Lyon, F-69003 Lyon, Universite Lyon 1 and IN2P3/CNRS, UMR 5822, F-69622 Villeurbanne (France); Freud, N.; Letang, J.M. [Institut National des Sciences Appliquees de Lyon, Laboratoire de Controle Non-Destructif par Rayonnements Ionisants (France); Poizat, J.C.; Ray, C.; Testa, M. [Institut de Physique Nucleaire de Lyon, Universite de Lyon, F-69003 Lyon, Universite Lyon 1 and IN2P3/CNRS, UMR 5822, F-69622 Villeurbanne (France)

2009-03-15

A key point in the quality control of ion therapy is real-time monitoring and imaging of the dose delivered to the patient. Among the possible signals that can be used to make such a monitoring, prompt gamma-rays issued from nuclear fragmentation are possible candidates, provided the correlation between the emission profile and the primary beam range can be established. By means of simultaneous energy and time-of-flight discrimination, we could measure the longitudinal profile of the prompt gamma-rays emitted by 73 MeV/u carbon ions stopping inside a PMMA target. This technique allowed us to minimize the shielding against neutrons and scattered gamma rays, and to find a good correlation between the prompt-gamma profile and the ion range. This profile was studied as a function of the observation angle. By extrapolating our results to higher energies and realistic detection efficiencies, we showed that prompt gamma-ray measurements make it feasible to control in real time the longitudinal dose during ion therapy treatments.

Quantitative evaluation of high-energy O− ion particle flux in a DC magnetron sputter plasma with an indium-tin-oxide target

International Nuclear Information System (INIS)

Suyama, Taku; Bae, Hansin; Setaka, Kenta; Ogawa, Hayato; Fukuoka, Yushi; Suzuki, Haruka; Toyoda, Hirotaka

2017-01-01

O − ion flux from the indium tin oxide (ITO) sputter target under Ar ion bombardment is quantitatively evaluated using a calorimetry method. Using a mass spectrometer with an energy analyzer, O − energy distribution is measured with spatial dependence. Directional high-energy O − ion ejected from the target surface is observed. Using a calorimetry method, localized heat flux originated from high-energy O − ion is measured. From absolute evaluation of the heat flux from O − ion, O − particle flux in order of 10 18 m −2 s −1 is evaluated at a distance of 10 cm from the target. Production yield of O − ion on the ITO target by one Ar + ion impingement at a kinetic energy of 244 eV is estimated to be 3.3  ×  10 −3 as the minimum value. (paper)

Improvement of the Energy Stability of the Single Ion Microbeam

International Nuclear Information System (INIS)

Zhan Furu; Qi Xuehong; Xu Mingliang; Chen Lianyun; Yu Zengliang

2008-01-01

Energy instability strongly affects the state and the beam size of the single ion microbeam. A facility based on the Generating Voltmeter was developed to improve the energy stability of the CAS-LIBB (Chinese Academy of Sciences, key laboratory of ion beam bioengineering) single ion microbeam. This paper presents the analysis of the energy instability of the single ion microbeam. A simplified theoretical model is set up to calculate the relationship between the energy instability and the beam spot size. By using this technique, the energy instability is adjusted to about 1%. Stable run-time is over 6 hours. The radius of the single ion beam is reduced by 10% compared to the previous one.

Improving the signal-to-noise ratio in mass and ion kinetic energy spectrometers

International Nuclear Information System (INIS)

Brenton, A.G.; Beynon, J.H.; Morgan, R.P.

1979-01-01

The signal-to-noise ratio in mass and ion kinetic energy spectrometers is limited by noise generated from the presence of scattered ions and neutrals. Methods of eliminating this are illustrated with reference to the ZAB-2F instrument manufactured by VG-Micromass Ltd. It is estimated that after the modifications the instrument is capable, on a routine basis, of measuring peaks corresponding to the arrival of ions at a rate of the order of 1 ion s -1 . (Auth.)

Electrostatic analyzer for electron and ion energy in glow discharge tube

International Nuclear Information System (INIS)

Bong Kil Yeon.

1984-01-01

The project, the construction and use of an electrostatic energy analyser (Faraday Cup) are described explaining physically its working mechanism. The analyser was used in a glow discharge tube with air and an air-argon mixture. A chapter with the theory of the glow discharge is included. The ion and electron temperatures, the plasma potential and the distribution function for ions and electrons were measured. The electron temperature and plasma potential were also measured using a Langmuir probe and the results show reasonable agreement with the results of the analyser. Good fits of the experimental electron and ion distribution functions were obtained with Maxwellian distributions centered values near the plasma potential. Finally, we discuss the performance of the analyser compared to Langmuir probes. (author) [pt

Generation of intense, high-energy ion pulses by magnetic compression of ion rings

International Nuclear Information System (INIS)

Kapetanakos, C.A.

1981-01-01

A system based on the magnetic compression of ion rings, for generating intense (High-current), high-energy ion pulses that are guided to a target without a metallic wall or an applied external magnetic field includes a vacuum chamber; an inverse reflex tetrode for producing a hollow ion beam within the chamber; magnetic coils for producing a magnetic field, bo, along the axis of the chamber; a disc that sharpens a magnetic cusp for providing a rotational velocity to the beam and causing the beam to rotate; first and second gate coils for producing fast-rising magnetic field gates, the gates being spaced apart, each gate modifying a corresponding magnetic mirror peak (Near and far peaks) for trapping or extracting the ions from the magnetic mirror, the ions forming a ring or layer having rotational energy; a metal liner for generating by magnetic flux compression a high, time-varying magnetic field, the time-varying magnetic field progressively increasing the kinetic energy of the ions, the magnetic field from the second gate coil decreasing the far mirror peak at the end of the compression for extracting the trapped rotating ions from the confining mirror; and a disc that sharpens a magnetic half-cusp for increasing the translational velocity of the ion beam. The system utilizes the self-magnetic field of the rotating, propagating ion beam to prevent the beam from expanding radially upon extraction

Remedial pulse programme for the production of monoenergetic ion beams of low energy

International Nuclear Information System (INIS)

Olubuyide, O.A.

1975-01-01

The technique involves an extension of sequential pulse techniques. An ion swarm is produced in a conventional mass-spectrometer ion source by a short electron beam pulse. Immediately, this swarm is accelerated impulsively by a short high voltage pulse on the repeller. The principal disadvantage of impulsive acceleration is that the final energy distribution of the ion swarm is broad especially at the lowest energies. At some instant during the passage of the ion swarm across the chamber second pulse is applied to the repeller--a ''remedial'' pulse which will accelerate the ions throughout the remainder of their passage and whose amplitude will be time-dependent. Slower ions must travel a greater distance in this ''remedial'' field than faster ions and will experience a proportionately greater increase in velocity from it. In this way, the remedial pulse can cause all the ions to acquire the same velocity at the exit slit. A limited experimental investigation has been made to examine the application of the proposed remedial pulse technique to existing ion sources. Application of the remedial pulse to impulsively-accelerated ion swarms reduced the energy distribution in the manner predicted by the theory but the quantitative reduction measured experimentally--a factor of approximately 2--was substantially less than the theoretical prediction of a factor of approximately 4. The limitations were characterized and a means of overcoming them was suggested in a new ion source of improved design. (Diss. Abstr. Int., B)

Conserved charge fluctuations using the D measure in heavy-ion collisions

Science.gov (United States)

Mishra, D. K.; Netrakanti, P. K.; Garg, P.

2017-05-01

We study the net-charge fluctuation D -measure variable, in high-energy heavy-ion collisions in heavy-ion jet interaction generator (HIJING), ultrarelativistic quantum molecular dynamics (UrQMD), and hadron resonance gas (HRG) models for various center-of-mass energies (√{sNN}). The effects of kinematic acceptance and resonance decay, in the pseudorapidity acceptance interval (Δ η ) and lower transverse momentum (pTmin) threshold, on fluctuation measures are discussed. A strong dependence of D with the Δ η in HIJING and UrQMD models is observed as opposed to results obtained from the HRG model. The dissipation of fluctuation signal is estimated by fitting the D measure as a function of the Δ η . An extrapolated function for higher Δ η values at lower √{sNN} is different from the results obtained from models. Particle species dependence of D and the effect of the pTmin selection threshold are discussed in HIJING and HRG models. The comparison of D , at midrapidity, of net-charge fluctuations at various √{sNN} obtained from the models with the data from the A Large Ion Collider Experiment (ALICE) experiment is discussed. The results from the present paper as a function of Δ η and √{sNN} will provide a baseline for comparison to experimental measurements.

Prototyping of beam position monitor for medium energy beam transport section of RAON heavy ion accelerator

Energy Technology Data Exchange (ETDEWEB)

Jang, Hyojae, E-mail: lkcom@ibs.re.kr; Jin, Hyunchang; Jang, Ji-Ho; Hong, In-Seok [Rare Isotope Science Project, Institute for Basic Science, Daejeon (Korea, Republic of)

2016-02-15

A heavy ion accelerator, RAON is going to be built by Rare Isotope Science Project in Korea. Its target is to accelerate various stable ions such as uranium, proton, and xenon from electron cyclotron resonance ion source and some rare isotopes from isotope separation on-line. The beam shaping, charge selection, and modulation should be applied to the ions from these ion sources because RAON adopts a superconducting linear accelerator structure for beam acceleration. For such treatment, low energy beam transport, radio frequency quadrupole, and medium energy beam transport (MEBT) will be installed in injector part of RAON accelerator. Recently, development of a prototype of stripline beam position monitor (BPM) to measure the position of ion beams in MEBT section is under way. In this presentation, design of stripline, electromagnetic (EM) simulation results, and RF measurement test results obtained from the prototyped BPM will be described.

Low energy cross section data for ion-molecule reactions in hydrogen systems and for charge transfer of multiply charged ions with atoms and molecules

International Nuclear Information System (INIS)

Okuno, Kazuhiko

2007-04-01

Systematic cross section measurements for ion-molecule reactions in hydrogen systems and for charge transfer of multiply charged ions in low energy collisions with atoms and molecules have been performed continuously by the identical apparatus installed with an octo-pole ion beam guide (OPIG) since 1980 till 2004. Recently, all of accumulated cross section data for a hundred collision systems has been entered into CMOL and CHART of the NIFS atomic and molecular numerical database together with some related cross section data. In this present paper, complicated ion-molecule reactions in hydrogen systems are revealed and the brief outlines of specific properties in low energy charge transfer collisions of multiply charged ions with atoms and molecules are introduced. (author)

Construction, characterization and applications of a compact mass-resolved low-energy ion beam system

International Nuclear Information System (INIS)

Lau, W.M.; Feng, X.; Bello, I.; Sant, S.; Foo, K.K.; Lawson, R.P.W.

1991-01-01

A compact mass-resolved low-energy ion beam system has been constructed in which ions are extracted from a Colutron ion source, focused by an einzel lens, mass-selected by a Wien filter, refocused by a second einzel lens into an ultrahigh vacuum target chamber, and finally decelerated with a five-electrode lens. The design of the deceleration lens was assisted by computer simulation including space-charge effects with an ion trajectory software (CHDEN). The system performance has been characterized with a quadrupole mass spectrometer and an energy analyzer along the beam axis. For example, argon ions can be transported at keV and decelerated to 10 eV with an energy spread of ±0.5 eV. The total current measured by a Faraday cage at the exit of the deceleration lens in the energy range of 10-200 eV is about 1-5 μA. The ion current density was higher than 100 μA/cm 2 at 50 eV but decreased to 10-20 μA/cm 2 at 10 eV. The mass resolution was estimated to be 40 under the present operation configuration. The system has been used to produce interesting results in both ion beam etching and deposition. (orig.)

Measurements of the charge exchange and dissociation cross-sections of the H{sub 2}+ ion in a wide energy range; Mesures des sections efficaces d'echange de charge et de dissociation des ions H{sub 2}{sup +} dans une large gamme d'energie (25 - 250 keV)

Energy Technology Data Exchange (ETDEWEB)

Guidini, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1962-07-01

The dissociation, ionisation, and charge exchange cross-sections of molecular hydrogen ions H{sub 2}{sup +} passing through various gases, have been measured as a function of the energy of the ions. The energy range studied was from 25 to 250 keV. The reaction products, analysed by a magnetic field according to their e/m ratio, are collected on scintillation detectors. Two methods have made it possible to separate the various reactions leading to the formation of particles having the same e/m ratio. The first separates the particles according to their energy, the other selects those arriving simultaneously on two different detectors. The results show a large variation in the charge exchange cross-section with the energy of the H{sub 2}{sup +} ions. The variations in the dissociation and ionisation cross-sections are less pronounced. For a given energy, the values of the cross-sections increase with the atomic weight of the target particles. These measurements have been extended to the case of H{sub 2}{sup +} ions passing through a target of charged particles. Preliminary results show an increase in the cross-sections as compared to the preceding case. Finally the scattering of the reaction products has been studied; this scattering is due to the fact that the molecules formed during a reaction are in an unstable state and the nuclei or atoms diverge from each other. (author) [French] Les sections efficaces de dissociation, d'ionisation et d'echange de charge d'ions hydrogene moleculaires H{sub 2}{sup +} traversant differents gaz, ont ete mesurees en fonction de l'energie des ions. La gamme d'energie exploree est comprise entre 25 et 250 keV. Les produits de reactions, analyses suivant leur rapport e/m par un champ magnetique, sont recus sur des detecteurs a scintillations. Deux methodes ont permis de separer les diverses reactions conduisant a la formation de particules ayant meme rapport e/m. L'une classe les particules secondaires en energie, l'autre selectionne

High-energy acceleration of an intense negative ion beam

International Nuclear Information System (INIS)

Takeiri, Y.; Ando, A.; Kaneko, O.

1995-02-01

A high-current H - ion beam has been accelerated with the two-stage acceleration. A large negative hydrogen ion source with an external magnetic filter produces more than 10 A of the H - ions from the grid area of 25cm x 50cm with the arc efficiency of 0.1 A/kW by seeding a small amount of cesium. The H - ion current increases according to the 3/2-power of the total beam energy. A 13.6 A of H - ion beam has been accelerated to 125 keV at the operational gas pressure of 3.4 mTorr. The optimum beam acceleration is achieved with nearly the same electric fields in the first and the second acceleration gaps on condition that the ratio of the first acceleration to the extraction electric fields is adjusted for an aspect ratio of the extraction gap. The ratio of the acceleration drain current to the H - ion current is more than 1.7. That is mainly due to the secondary electron generated by the incident H - ions on the extraction grid and the electron suppression grid. The neutralization efficiency was measured and agrees with the theoretical calculation result. (author)

Atomic mixing of metallic bilayers Ni/Ti irradiated with high energy heavy ions; Etude du melange ionique de bicouches metalliques Ni/Ti irradiees avec des ions lourds de haute energie

Energy Technology Data Exchange (ETDEWEB)

Leguay, R

1994-09-26

We have studied the ionic mixing of Nl(105 angstrom) bilayers irradiated, at 80 and 300 K. with GeV heavy ions. In this energy range, the energy transfer from the incident ions to the target occurs mainly through electronic excitations. We have shown that this energy transfer induces a strong ionic mixing at the Nl/Ti interface. The thickness of the mixed interlayer increases with the fluence. At low fluences (10{sup 12} ions/cm{sup 2}), the Nl/Ti interface is rough ; at higher fluences (10{sup 13} ions/cm{sup 2}) a homogeneous mixed interlayer appears ; and at even higher fluences (some 10{sup 13} ions/cm{sup 2}) a preferential diffusion of Ni into Ti is clearly seen. The characterization techniques used are: (1) electrical resistivity measurements which allow to follow in situ the damage kinetic. (II) neutron and X-ray reflectometry. (III) elaboration of transverse cuts on which was performed energy loss spectroscopy. (II) and (III) allow the determination of the concentration profiles of the different species present in the sample. (IV) transmission electron microscopy on the transverse cuts which gives a direct image of the different layers. (author). 11 refs., 103 figs., 23 tabs., 2 appends.

Structuring of silicon with low energy focused ion beams

Energy Technology Data Exchange (ETDEWEB)

Nebiker, P.W.; Doebeli, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Muehle, R. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

1997-09-01

The defect production in silicon induced by focused ion beam irradiation as a function of energy and projectile mass has been investigated and compared to the measured sputter yield. The aim was to find optimal beam parameters for the structuring of semiconductors with a minimum amount of defects produced per removed atom. (author) 2 figs., 2 refs.

Real-time control of ion density and ion energy in chlorine inductively coupled plasma etch processing

International Nuclear Information System (INIS)

Chang, C.-H.; Leou, K.-C.; Lin Chaung; Lin, T.-L.; Tseng, C.-W.; Tsai, C.-H.

2003-01-01

In this study, we have experimentally demonstrated the real-time closed-loop control of both ion density and ion energy in a chlorine inductively coupled plasma etcher. To measure positive ion density, the trace rare gases-optical emission spectroscopy is used to measure the chlorine positive ion density. An rf voltage probe is adopted to measure the root-mean-square rf voltage on the electrostatic chuck which is linearly dependent on sheath voltage. One actuator is a 13.56 MHz rf generator to drive the inductive coil seated on a ceramic window. The second actuator is also a 13.56 MHz rf generator to power the electrostatic chuck. The closed-loop controller is designed to compensate for process drift, process disturbance, and pilot wafer effect and to minimize steady-state error of plasma parameters. This controller has been used to control the etch process of unpatterned polysilicon. The experimental results showed that the closed-loop control had a better repeatability of plasma parameters compared with open-loop control. The closed-loop control can eliminate the process disturbance resulting from reflected power. In addition, experimental results also demonstrated that closed-loop control has a better reproducibility in etch rate as compared with open-loop control

Mapping and uncertainty analysis of energy and pitch angle phase space in the DIII-D fast ion loss detector

Energy Technology Data Exchange (ETDEWEB)

Pace, D. C., E-mail: pacedc@fusion.gat.com; Fisher, R. K.; Van Zeeland, M. A. [General Atomics, PO Box 85608, San Diego, California 92186-5608 (United States); Pipes, R. [Department of Physics, University of Hawaii, Hilo, Hawaii 96720-4091 (United States)

2014-11-15

New phase space mapping and uncertainty analysis of energetic ion loss data in the DIII-D tokamak provides experimental results that serve as valuable constraints in first-principles simulations of energetic ion transport. Beam ion losses are measured by the fast ion loss detector (FILD) diagnostic system consisting of two magnetic spectrometers placed independently along the outer wall. Monte Carlo simulations of mono-energetic and single-pitch ions reaching the FILDs are used to determine the expected uncertainty in the measurements. Modeling shows that the variation in gyrophase of 80 keV beam ions at the FILD aperture can produce an apparent measured energy signature spanning across 50-140 keV. These calculations compare favorably with experiments in which neutral beam prompt loss provides a well known energy and pitch distribution.

Mapping and uncertainty analysis of energy and pitch angle phase space in the DIII-D fast ion loss detector.

Science.gov (United States)

Pace, D C; Pipes, R; Fisher, R K; Van Zeeland, M A

2014-11-01

New phase space mapping and uncertainty analysis of energetic ion loss data in the DIII-D tokamak provides experimental results that serve as valuable constraints in first-principles simulations of energetic ion transport. Beam ion losses are measured by the fast ion loss detector (FILD) diagnostic system consisting of two magnetic spectrometers placed independently along the outer wall. Monte Carlo simulations of mono-energetic and single-pitch ions reaching the FILDs are used to determine the expected uncertainty in the measurements. Modeling shows that the variation in gyrophase of 80 keV beam ions at the FILD aperture can produce an apparent measured energy signature spanning across 50-140 keV. These calculations compare favorably with experiments in which neutral beam prompt loss provides a well known energy and pitch distribution.

Mean excitation energies for molecular ions

DEFF Research Database (Denmark)

Jensen, Phillip W.K.; Sauer, Stephan P.A.; Oddershede, Jens

2017-01-01

The essential material constant that determines the bulk of the stopping power of high energy projectiles, the mean excitation energy, is calculated for a range of smaller molecular ions using the RPA method. It is demonstrated that the mean excitation energy of both molecules and atoms increase...

ECR ion source for variable energy cyclotron

Energy Technology Data Exchange (ETDEWEB)

Bose, D K; Taki, G S; Nabhiraj, P Y; Pal, G; Dasgupta, B; Mallik, C; Das, S K; Bandopadhaya, D K; Bhandari, R K [Variable Energy Cyclotron Centre, Calcutta (India)

1995-09-01

Some performance characteristics of 6.4 GHz two stage ECR ion source which was under development at this centre is presented. The present ion source will facilitate acceleration of light heavy ions with the existing k=130 variable energy cyclotron. Multiply charged heavy ion (MCHI) beam from the source will also be utilized for atomic physics studies. Oxygen beam has already been used for ion implantation studies. The external injection system under development is nearing completion. Heavy ion beam from cyclotron is expected by end of 1995. (author).

Guided transmission of highly charged ions through nanocapillaries in PET. Study of the energy dependencies

International Nuclear Information System (INIS)

Helhammer, R.; Pesic, Z.D.; Sobocinski, P.; Bundesmann, J.; Fink, D.; Stolterfoht, N.; Sulik, B.

2004-01-01

Full text: Recently we reported experiments in which slow highly charged ions are transmitted through nanocapillaries of 100nm diameter in an insulating PET foil of 10μm thickness [1]. The results of this work differ significantly from previous studies, which have been focused on capillaries in metals [2]. We measured the transmission of 3 keV Ne 7+ ions through the capillaries and focused the attention on ions whose charge has not changed during the passage through the capillary. The observation that the angular distribution for PET has a peak maximum whose position is equal to the tilt angle indicates a guiding of the Ne 7+ ion within the capillary. This guiding shows that the inner walls of the capillaries are charged up in a self-organizing process and collisions with the surface are finally prevented. We studied the time evolution of the capillary guiding as well as dependencies on the tilt angle [3]. Our most recent measurements were focussed on the investigation of the energy dependency for the guiding of Ne 7+ through capillaries. The measurements were done in an energy range from 2 keV up to 10 keV.We measured higher guiding efficiency for lower energies consistent with a previously developed model, which predicted an increase of the guiding efficiency with decreasing projectile energy [3]. In addition we found the effect of a narrower width of the angular distribution of transmitted ions. This effect is also well described by the model. However, further work is needed to explain the amount of charges to build up the deflection field at the end of the capillaries

Ion acceleration with a narrow energy spectrum by nanosecond laser-irradiation of solid target

Energy Technology Data Exchange (ETDEWEB)

Altana, C., E-mail: altana@lns.infn.it [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Università degli Studi di Catania, Via S. Sofia 64, 95123 Catania (Italy); Lanzalone, G. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Via S. Sofia 62, 95123 Catania (Italy); Università degli Studi di Enna “Kore,” Via delle Olimpiadi, 94100 Enna (Italy); Mascali, D.; Cirrone, G. A. P.; Schillaci, F.; Tudisco, S. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Via S. Sofia 62, 95123 Catania (Italy); Muoio, A. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Messina, Viale F. D’Alcontres 31, 98166 Messina (Italy)

2016-02-15

In laser-driven plasma, ion acceleration of aluminum with the production of a quasi-monoenergetic beam has occurred. A useful device to analyze the ions is the Thomson parabolas spectrometer, a well-known diagnostic that is able to obtain information on charge-to-mass ratio and energy distribution of the charged particles. At the LENS (Laser Energy for Nuclear Science) laboratory of INFN-LNS in Catania, experimental measures were carried out; the features of LENS are: Q-switched Nd:YAG laser with 2 J laser energy, 1064 nm fundamental wavelengths, and 6 ns pulse duration.

Transmission sputtering of gold thin-films by low-energy (< 1 keV) xenon ions: I. The system and the measurement

International Nuclear Information System (INIS)

Ayrault, G.; Seidman, D.N.

1978-01-01

A novel system for direct measurement of the transmission sputtering yields of ion-irradiated thin films is described. The system was specifically designed for the study of the transmission sputtering caused by low energy ( 0 A thick) which was mounted in a JEM 200 transmission electron-microscope holder. The temperature of the specimen could be varied between approx. 25 and 300 K employing a continuous-transfer liquid-helium cryostat. The particles (atoms or ions) ejected from the unirradiated surface of the gold thin-film were detected by two channetron electron-multiplier arrays in the Chevron configuration; the Chevron detector was able to detect individual transmission sputtered particles when operated in the saturated mode. To further enhance resolution the electron cascades, produced by the CEMA, were amplified and shaped electronically into uniform square pulses. The shaped signals were detected with an Ithaco 391A lock-in amplifier (LIA). With the aid of a ratiometer feature in the LIA we were able to measure directly the ratio of the transmission sputtered-current (I/sub t/) to the incident ion-current (I/sub b/); for I/sub b/ = μA cm -2 a ratio of I/sub t//I/sub b/ as small as 1 x 10 -9 was measured. A detailed discussion of the calibration procedure and the experimental errors, involved in this technique, are also presented. 45 references

Sputtering of carbon using hydrogen ion beams with energies of 60–800 eV

Energy Technology Data Exchange (ETDEWEB)

Sidorov, Dmitry S., E-mail: dmitrisidoroff@rambler.ru [Nizhny Novgorod State University, 23 Gagarina Avenue, Nizhny Novgorod, Nizhny Novgorod Region 603950 (Russian Federation); Chkhalo, Nikolay I., E-mail: chkhalo@ipm.sci-nnov.ru [Institute for Physics of Microstructures RAS, Academicheskaya Str. 7, Afonino, Nizhny Novgorod Region, Kstovsky District, Kstovo Region 603087 (Russian Federation); Mikhailenko, Mikhail S.; Pestov, Alexey E.; Polkovnikov, Vladimir N. [Institute for Physics of Microstructures RAS, Academicheskaya Str. 7, Afonino, Nizhny Novgorod Region, Kstovsky District, Kstovo Region 603087 (Russian Federation)

2016-11-15

This article presents the result of a study on the sputtering of carbon films by low-energy hydrogen ions. In particular, the etching rate and surface roughness were measured. The range of energies where the sputtering switches from pure chemical to a combination of chemical and physical mechanisms was determined. It is shown that Sigmund’s theory for ion etching does not work well for fields of energy less than 150 eV and that it accurately describes the dependence of a sputtering coefficient on ion energy for energies greater than 300 eV. A strong smoothing effect for the surface of carbon film was also found. This result is interesting in itself and for its significance for the manufacture of super-smooth surfaces for X-ray applications.

Study of ion tracks by micro-probe ion energy loss spectroscopy

Czech Academy of Sciences Publication Activity Database

Vacík, Jiří; Havránek, Vladimír; Hnatowicz, Vladimír; Horák, Pavel; Fink, Dietmar; Apel, P. Yu.

2014-01-01

Roč. 332, AUG (2014), s. 308-311 ISSN 0168-583X. [21st International Conference on Ion Beam Analysis (IBA). Seattle, 23.06.2013-28.06.2013] R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : ion energy loss spectrometry * single ion track * microprobe * tomography Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.124, year: 2014

Biomaterial imaging with MeV-energy heavy ion beams

Energy Technology Data Exchange (ETDEWEB)

Seki, Toshio, E-mail: seki@sakura.nucleng.kyoto-u.ac.jp [Department of Nuclear Engineering, Kyoto Univ., Uji, Kyoto 611-0011 (Japan); CREST, Japan Science and Technology Agency (JST), Chiyoda, Tokyo 102-0075 (Japan); Wakamatsu, Yoshinobu; Nakagawa, Shunichiro [Department of Nuclear Engineering, Kyoto Univ., Uji, Kyoto 611-0011 (Japan); Aoki, Takaaki [Department of Electronic Science and Engineering, Kyoto Univ., Nishikyo, Kyoto 615-8510 (Japan); CREST, Japan Science and Technology Agency (JST), Chiyoda, Tokyo 102-0075 (Japan); Ishihara, Akihiko [Laboratory of Cell Biology and Life Science, Graduate School of Human and Environmental Studies, Kyoto Univ., Sakyo, Kyoto 606-8501 (Japan); Matsuo, Jiro [Quantum Science and Engineering Center, Kyoto Univ., Uji, Kyoto 611-0011 (Japan); CREST, Japan Science and Technology Agency (JST), Chiyoda, Tokyo 102-0075 (Japan)

2014-08-01

The spatial distribution of several chemical compounds in biological tissues and cells can be obtained with mass spectrometry imaging (MSI). In conventional secondary ion mass spectrometry (SIMS) with keV-energy ion beams, elastic collisions occur between projectiles and atoms of constituent molecules. The collisions produce fragments, making the acquisition of molecular information difficult. In contrast, ion beams with MeV-energy excite near-surface electrons and enhance the ionization of high-mass molecules; hence, SIMS spectra of fragment-suppressed ionized molecules can be obtained with MeV-SIMS. To compare between MeV and conventional SIMS, we used the two methods based on MeV and Bi{sub 3}-keV ions, respectively, to obtain molecular images of rat cerebellum. Conventional SIMS images of m/z 184 were clearly observed, but with the Bi{sub 3} ion, the distribution of the molecule with m/z 772.5 could be observed with much difficulty. This effect was attributed to the low secondary ion yields and we could not get many signal counts with keV-energy beam. On the other hand, intact molecular ion distributions of lipids were clearly observed with MeV-SIMS, although the mass of all lipid molecules was higher than 500 Da. The peaks of intact molecular ions in MeV-SIMS spectra allowed us to assign the mass. The high secondary ion sensitivity with MeV-energy heavy ions is very useful in biomaterial analysis.

Biomaterial imaging with MeV-energy heavy ion beams

International Nuclear Information System (INIS)

Seki, Toshio; Wakamatsu, Yoshinobu; Nakagawa, Shunichiro; Aoki, Takaaki; Ishihara, Akihiko; Matsuo, Jiro

2014-01-01

The spatial distribution of several chemical compounds in biological tissues and cells can be obtained with mass spectrometry imaging (MSI). In conventional secondary ion mass spectrometry (SIMS) with keV-energy ion beams, elastic collisions occur between projectiles and atoms of constituent molecules. The collisions produce fragments, making the acquisition of molecular information difficult. In contrast, ion beams with MeV-energy excite near-surface electrons and enhance the ionization of high-mass molecules; hence, SIMS spectra of fragment-suppressed ionized molecules can be obtained with MeV-SIMS. To compare between MeV and conventional SIMS, we used the two methods based on MeV and Bi 3 -keV ions, respectively, to obtain molecular images of rat cerebellum. Conventional SIMS images of m/z 184 were clearly observed, but with the Bi 3 ion, the distribution of the molecule with m/z 772.5 could be observed with much difficulty. This effect was attributed to the low secondary ion yields and we could not get many signal counts with keV-energy beam. On the other hand, intact molecular ion distributions of lipids were clearly observed with MeV-SIMS, although the mass of all lipid molecules was higher than 500 Da. The peaks of intact molecular ions in MeV-SIMS spectra allowed us to assign the mass. The high secondary ion sensitivity with MeV-energy heavy ions is very useful in biomaterial analysis

Time-of-flight measurements of heavy ions using Si PIN diodes

Energy Technology Data Exchange (ETDEWEB)

Strekalovsky, A. O., E-mail: alex.strek@bk.ru; Kamanin, D. V. [Joint Institute for Nuclear Research (Russian Federation); Pyatkov, Yu. V. [National Nuclear Research University MEPhI (Moscow Engineering Physics Institute) (Russian Federation); Kondratyev, N. A.; Zhuchko, V. E. [Joint Institute for Nuclear Research (Russian Federation); Ilić, S. [University of Novi Sad (Serbia); Alexandrov, A. A.; Alexandrova, I. A. [Joint Institute for Nuclear Research (Russian Federation); Jacobs, N. [University of Stellenbosch, Faculty of Military Science, Military Academy (South Africa); Kuznetsova, E. A.; Mishinsky, G. V.; Strekalovsky, O. V. [Joint Institute for Nuclear Research (Russian Federation)

2016-12-15

A new off-line timing method for PIN diode signals is presented which allows the plasma delay effect to be suppressed. Velocities of heavy ions measured by the new method are in good agreement within a wide range of masses and energies with velocities measured by time stamp detectors based on microchannel plates.

Energy transfer and quenching processes of excited uranyl ion and lanthanide ions in solutions

International Nuclear Information System (INIS)

Yamamura, Tomoo; Tomiyasu, Hiroshi

1995-01-01

Deactivation processes of photoexcited uranyl ion by various lanthanide ions in aqueous solution were studied. Each lanthanide ions show different interaction with excited uranyl ion depending on its lowest excited energy level, the number of 4f electrons and the acid concentration of the solution. (author)

Investigation of the energy loss and the charge state of high energy heavy ions in a hydrogen plasma

International Nuclear Information System (INIS)

Dietrich, K.G.

1991-07-01

For heavy ions with energy of 1.4 to 5.9 MeV/u the energy loss and charge state after transmission through a totally ionized hydrogen plasma are investigated. Plasma target was a Z-pinch device incorporated in the beam optics of the accelerator by a pumping system. In the 20 cm long pinch hydrogen plasmas with densities up to 1.5x10 19 cm -3 and temperatures above 5 eV are produced, with ionization efficiency higher than 99%. The ions pass the plasma on the symmetry axis of the plasma column through small apertures in the electrodes. The energy loss was measured by time-of-flight method, the plasma density by interferometry along the pinch axis. For the first time the ion charge after transmission through the plasma has been determined by a charge spectrometer being a combination of a dipole magnet and a position sensitive detector with high time resolution. A growth of the average charge of heavy ions in plasma higher than the equilibrium charge in cold gas was discovered, caused by a reduction of electron capture by fast heavy ions in ionized matter. The electron loss rates in plasma and cold gas are equal. (orig./AH) [de

Intermediate energy proton and light-ion scattering

International Nuclear Information System (INIS)

Moss, J.M.

1981-01-01

A review is presented of recent (1979-81) developments in the field of intermediate-energy proton and light-ion scattering from nuclei. New theoretical and calculational techniques of particular interest to experimentalists are discussed. Emphasis is placed on topics in nuclear structure physics - giant resonances, pion-condensation precursor phenomena, and polarization transfer (spin-flip) experiments - where intermediate energy proton and light-ion scattering has made new and unique contributions

Dose measurement of ion implanted silicon by RBS technique

International Nuclear Information System (INIS)

Kamawanna, Teerasak; Intarasiri, Saweat; Prapunsri, Chowunchun; Thongleurm, Chome; Maleepatra, Saenee; Singkarat, Somsorn

2003-10-01

Surface modification can be achieved by ion implantation. This study used a 1 mm thick silicon wafer as a target which was implanted with Ar+ at 80 keV. The degree of the modification depends on both the ion energy and the implanted dose. The distribution of argon in the silicon substrate and the absolute implanted dose can be measured by using Rutherford Backscattering Spectrometry (RBS). These investigations utilized a 1.7 MV Tandetron accelerator system at Chiang Mai University. The dose determination by a direct calculation is in agreement with the simulation by the SIMNRA code

Electron energy recovery system for negative ion sources

International Nuclear Information System (INIS)

Dagenhart, W.K.; Stirling, W.L.

1982-01-01

An electron energy recovery system for negative ion sources is provided. The system, employs crossed electric and magnetic fields to separate the electrons from ions as they are extracted from a negative ion source plasma generator and before the ions are accelerated to their full kinetic energy. With the electric and magnetic fields oriented 90* to each other, the electrons are separated from the plasma and remain at approximately the electrical potential of the generator in which they were generated. The electrons migrate from the ion beam path in a precessing motion out of the ion accelerating field region into an electron recovery region provided by a specially designed electron collector electrode. The electron collector electrode is uniformly spaced from a surface of the ion generator which is transverse to the direction of migration of the electrons and the two surfaces are contoured in a matching relationship which departs from a planar configuration to provide an electric field component in the recovery region which is parallel to the magnetic field thereby forcing the electrons to be directed into and collected by the electron collector electrode. The collector electrode is maintained at a potential slightly positive with respect to the ion generator so that the electrons are collected at a small fraction of the full accelerating supply voltage energy

VUV photoionization of acetamide studied by electron/ion coincidence spectroscopy in the 8–24 eV photon energy range

International Nuclear Information System (INIS)

Schwell, Martin; Bénilan, Yves; Fray, Nicolas; Gazeau, Marie-Claire; Es-Sebbar, Et.; Garcia, Gustavo A.; Nahon, Laurent; Champion, Norbert; Leach, Sydney

2012-01-01

Highlights: ► We study the VUV photoionization of acetamide in the 8–24 eV photon energy range. ► Electron/ion coincidence measurements are performed using synchrotron radiation. ► The adiabatic ionization energy of acetamide is determined by TPEPICO measurements. ► VUV induced fragmentation pathways of acetamide are assigned and discussed. - Abstract: A VUV photoionization study of acetamide was carried out over the 8–24 eV photon energy range using synchrotron radiation and photoelectron/photoion coincidence (PEPICO) spectroscopy. Threshold photoelectron photoion coincidence (TPEPICO) measurements were also made. Photoion yield curves and branching ratios were measured for the parent ion and six fragment ions. The adiabatic ionization energy of acetamide was determined as I.E. (1 2 A′) = (9.71 ± 0.02) eV, in agreement with an earlier reported photoionization mass spectrometry (PIMS) value. The adiabatic energy of the first excited state of the ion, 1 2 A″, was determined to be ≈10.1 eV. Assignments of the fragment ions and the pathways of their formation by dissociative photoionization were made. The neutral species lost in the principal dissociative photoionization processes are CH 3 , NH 2 , NH 3 , CO, HCCO and NH 2 CO. Heats of formation are derived for all ions detected and are compared with literature values. Some astrophysical implications of these results are discussed.

Comparison of models of high energy heavy ion collision

International Nuclear Information System (INIS)

Gyulassy, M.

1977-01-01

Some of the main theoretical developments on heavy ion collisions at energies (0.1 to 2.0) GeV/nuc are reviewed. The fireball, firestreak, hydrodynamic (1-fluid, 2-fluids), ''row on row'', hard sphere and intranuclear cascades, and classical equations of motion models are discussed in detail. Results are compared to each other and to measured Ne + U → p + X reactions

LINAC4 low energy beam measurements

CERN Document Server

Hein, L M; Lallement, J B; Lombardi, A M; Midttun, O; Posocco, P; Scrivens, R

2012-01-01

Linac4 is a 160 MeV normal-conducting linear accelerator for negative Hydrogen ions (H−), which will replace the 50 MeV proton Linac (Linac2) as linear injector for the CERN accelerators. The low energy part, comprising a 45 keV Low Energy Beam Transport system (LEBT), a 3 MeV Radiofrequency Quadrupole (RFQ) and a Medium Energy Beam Transport (MEBT) is being assembled in a dedicated test stand for pre-commissioning with a proton beam. During 2011 extensive measurements were done after the source and after the LEBT with the aim of preparing the RFQ commissioning and validating the simulation tools, indispensable for future source upgrades. The measurements have been thoroughly simulated with a multi-particle code, including 2D magnetic field maps, error studies, steering studies and the generation of beam distribution from measurements. Emittance, acceptance and transmission measurements will be presented and compared to the results of the simulations.

Simulation studies on measures to mitigate ion clouds

Energy Technology Data Exchange (ETDEWEB)

Babu Ganta, Prasanth; Masood, Ahmed; Rienen, Ursula van [Universitaet Rostock, Institut fuer Allgemeine Elektrotechnik (Germany); Sauerland, Dennis; Hillert, Wolfgang [Physikalisches Institut der Universitaet Bonn, ELSA (Germany); Meseck, Atoosa [HZB, Institut Beschleunigerphysik, Berlin (Germany)

2016-07-01

For future Energy Recovery Linacs (ERL), parasitic ions, which are generated by collisions of the beam and the rest gas in the vacuum chamber, present a limiting factor for the high current-low emittance electron beams. Clearing gaps, clearing electrodes and appropriate filling patterns are a remedy to keep the ion density in the accelerator at a level that allows for a minimum stability of the beam parameters. The MOEVE PIC Tracking code, which employs a 2D wake matrix, enables tracking simulations of the ion distribution over a relatively long period of up to thousands of interactions with the passing bunches. It enables to develop a deeper understanding of the ion-cloud behavior in order to design appropriate measures for their mitigation. For certain cases, it is sufficient to study the problem in 2D. Therefore, an additional 2D solver shall be implemented into MOEVE PIC Tracking in order to reduce the computation times. Numerical studies of ion cloud dynamics in beam guiding magnets and drift sections of electron machines will be shown and compared with experimental results obtained at the ELSA facility.

Dynamic electrochemical measurement of chloride ions

NARCIS (Netherlands)

Abbas, Yawar; de Graaf, Derk B.; Olthuis, Wouter; van den Berg, Albert

2016-01-01

This protocol describes the dynamic measurement of chloride ions using the transition time of a silver silver chloride (Ag/AgCl) electrode. Silver silver chloride electrode is used extensively for potentiometric measurement of chloride ions concentration in electrolyte. In this measurement,

Metastable decay and binding energies of van der Waals cluster ions

International Nuclear Information System (INIS)

Ernstberger, B.; Krause, H.; Neusser, H.J.

1991-01-01

In this work the appearance potentials for the metastable decay channel of a series of van der Waals dimer ions are presented. Ionization and metastable dissociation is achieved by resonance-enhanced two-photon absorption in a linear reflectron time-of-flight mass spectrometer. From the appearance potentials the binding energy of the neutral dimers is obtained and from the additionally measured ionization potentials binding energies of the dimer cations are achieved. The contribution of charge transfer resonance interaction to the binding in cluster ions is evaluated by investigation of several homo- and heterodimers of aromatic components and the heterodimer benzene/cyclohexane as an example for a dimer consisting of an aromatic and a nonaromatic component. (orig.)

Enhancement of optical absorption of Si (100) surfaces by low energy N+ ion beam irradiation

Science.gov (United States)

Bhowmik, Dipak; Karmakar, Prasanta

2018-05-01

The increase of optical absorption efficiency of Si (100) surface by 7 keV and 8 keV N+ ions bombardment has been reported here. A periodic ripple pattern on surface has been observed as well as silicon nitride is formed at the ion impact zones by these low energy N+ ion bombardment [P. Karmakar et al., J. Appl. Phys. 120, 025301 (2016)]. The light absorption efficiency increases due to the presence of silicon nitride compound as well as surface nanopatterns. The Atomic Force Microscopy (AFM) study shows the formation of periodic ripple pattern and increase of surface roughness with N+ ion energy. The enhancement of optical absorption by the ion bombarded Si, compared to the bare Si have been measured by UV - visible spectrophotometer.

Heavy ion reactions at high energies

International Nuclear Information System (INIS)

Jakobsson, Bo.

1977-01-01

A review on heavy ion experiments at energies >0.1GeV/nucleon is presented. Reaction cross-sections, isotope production cross-sections and pion production in nucleus-nucleus collisions are discussed. Some recent models for heavy ion reactions like the abrasion-ablation model, the fireball model and the different shock-wave models are also presented

Limitations to depth resolution in high-energy, heavy-ion elastic recoil detection analysis

International Nuclear Information System (INIS)

Elliman, R.G.; Palmer, G.R.; Ophel, T.R.; Timmers, H.

1998-01-01

The depth resolution of heavy-ion elastic recoil detection analysis was examined for Al and Co thin films ranging in thickness from 100 to 400 nm. Measurements were performed with 154 MeV Au ions as the incident beam, and recoils were detected using a gas ionisation detector. Energy spectra were extracted for the Al and Co recoils and the depth resolution determined as a function of film thickness from the width of the high- and low- energy edges. These results were compared with theoretical estimates calculated using the computer program DEPTH. (authors)

Coincidence measurements of slow recoil ions with projectile ions in 42-MeV Arq+-Ar collisions

International Nuclear Information System (INIS)

Tonuma, T.; Kumagai, H.; Matsuo, T.; Tawara, H.

1989-01-01

Slow Ar recoil-ion production cross sections by projectiles of 1.05-MeV/amu Ar q+ (q=4,6,8,10,12,14) were measured using a projectile-ion--recoil-ion coincidence technique. The present results indicate that the average recoil ion charges left-angle i right-angle increase with increasing the incident projectile charge q and the number of the lost and captured electrons from and/or into projectiles, whereas the projectile charge-changing cross sections for loss ionization decrease steeply with increasing q for low-charge-state projectiles, and those for transfer ionization increase rapidly with increasing q for high-charge-state projectiles. For Ar projectiles with q=10, which corresponds to the equilibrium charge state of Ar projectiles at the present collision energy, the average recoil-ion charges are nearly the same in both loss and transfer ionization, and a pure ionization process plays a much more important role in producing highly charged recoil ions, in contrast to projectile electron loss or transfer processes, which play a role in other projectile charge states

Improved beam-energy calibration technique for heavy ion accelerators

International Nuclear Information System (INIS)

Ferrero, A.M.J.; Garcia, A.; Gil, Salvador

1989-01-01

A simple technique for beam energy calibration of heavy-ion accelerators is presented. A thin hydrogenous target was bombarded with 12 C and 19 F, and the energies of the protons knocked out, elastically were measured at several angles using two detectors placed at equal angles on opposite sides of the beam. The use of these two detectors cancels the largest errors due to uncertainties in the angle and position at which the beam hits the target. An application of this energy calibration method to an electrostatic accelerator is described and the calibration constant of the analyzing magnet was obtained with an estimated error of 0.4 (Author) [es

Multidetector system for the identification of and measurement of the energies of heavy ions at intermediate energies; Systeme multidetecteur pour l`identification et la mesure des energies des ions lourds aux energies intermediaires

Energy Technology Data Exchange (ETDEWEB)

Samri, M; Beaulieu, L; Djerroud, B [Laval Univ., Quebec City, PQ (Canada). Dept. de Physique; and others

1994-12-31

A scintillation multidetector system composed (at the present time) of 80 detectors is described and its performance reported. It contains both phoswich and CsI detectors. A number of recent publications have shown that CsI or phoswich detectors do not have an adequately quantitative response to heavy ions in the intermediate energy range, but this difficulty can be avoided by calibrating the detectors for energy. In the present case, the use of the technique of secondary detector clusters is shown to be effective. Detection over a wide solid angle is possible. 19 refs., 3 tabs., 3 figs.

Energy loss straggling in Aluminium foils for Li and C ions in fractional energy loss limits (ΔE/E) ∼10-60%

Science.gov (United States)

Diwan, P. K.; Kumar, Sunil; Kumar, Shyam; Sharma, V.; Khan, S. A.; Avasthi, D. K.

2016-02-01

The energy loss straggling of Li and C ions in Al foils of various thicknesses has been measured, within the fractional energy loss limit (∆E/E) ∼ 10-60%. These measurements have been performed using the 15UD Pelletron accelerator facility available at Inter University Accelerator Centre (IUAC), New Delhi, India. The measured straggling values have been compared with the corresponding predicted values adopting popularly used collisional straggling formulations viz Bohr, Lindhard and Scharff, Bethe-Livingston, Titeica. In addition, the experimental data has been compared to the Yang et al. empirical formula and Close Form Model, recently proposed by Montanari et al. The straggling values derived by Titeica theory were found to be in better agreement with the measured values as compared to other straggling formulations. The charge-exchange straggling component has been estimated from the measured data based on Titeica's theory. Finally, a function of the ion effective charge and the energy loss fraction within the target has been fitted to the latter straggling component.

Energy Properties of Ion Acoustic Waves in Stable and Unstable Plasmas

DEFF Research Database (Denmark)

Jensen, Vagn Orla; Lynov, Jens-Peter

1979-01-01

Energy exchange between potential energy and ion kinetic energy in an ion acoustic wave is considered. In order to investigate the linear Landau damping or growth, the energy is calculated by use of first‐order quantities only so that nonlinear effects are not involved. It is found that for ion...... acoustic waves that are growing or damped in space the time average of the sum of the potential and the kinetic energy density is independent of position. Energy absorption spectra in particle velocity space are calculated; they are relatively broad and complicated functions. This shows that plasma ions...... of all velocities exchange energy with the wave....

A method for measuring light ion reaction cross-sections

International Nuclear Information System (INIS)

Carlson, R.F.; Ingemarsson, A.; Lantz, M.; Arendse, G.J.; Auce, A.; Cox, A.J.; Foertsch, S.V.; Jacobs, N.M.; Johansson, R.; Nyberg, J.; Peavy, J.; Renberg, P.-U.; Sundberg, O.; Stander, J.A.; Steyn, G.F.; Tibell, G.; Zorro, R.

2005-01-01

An experimental procedure for measuring reaction cross-sections of light ions in the energy range 20-50 MeV/nucleon, using a modified attenuation technique, is described. The detection method incorporates a forward detector that simultaneously measures the reaction cross-sections for five different sizes of the solid angle in steps from 99.1% to 99.8% of the total solid angle. The final reaction cross-section values are obtained by extrapolation to the full solid angle

A method for measuring light ion reaction cross sections

International Nuclear Information System (INIS)

Carlson, R.F.; Ingemarsson, A.; Lantz, M.

2005-03-01

An experimental procedure for measuring reaction cross sections of light ions in the energy range 20-50 MeV/nucleon, using a modified attenuation technique, is described. The detection method incorporates a forward detector that simultaneously measures the reaction cross sections for five different sizes of the solid angles in steps from 99.1 to 99.8% of the total solid angle. The final reaction cross section values are obtained by extrapolation to the full solid angle

The interaction of low energy ion beams with surfaces

International Nuclear Information System (INIS)

Carter, G.; Armour, D.G.

1981-01-01

Four of the most important physical processes which occur during ion plating and allied techniques (1) ion-induced (and energetic-atom-induced) desorption of adsorbed impurities from the substrate surface, (2) ion penetration and entrapment in the substrate and coating, (3) ion-induced sputtering of substrate and coating atoms and (4) recoil displacement of substrate and coating atoms leading to their intermixing. The ion and energetic atom energy range of importance is from thermal energies to the order of 1keV. Current understanding of these processes, supported by discussion of available experimental data, is reviewed. (Auth.)

The interactions of high-energy, highly charged Xe ions with buckyballs

International Nuclear Information System (INIS)

Ali, R.; Berry, H.G.; Cheng, S.

1994-01-01

Ionization and fragmentation have been measured for C 60 molecules bombarded by highly charged (up to 35+) xenon ions with energies ranging up to 625 MeV. The observed mass distribution of positively charged fragments is explained in terms of a theoretical model indicating that the total interaction cross section contains roughly equal contributions from (a) excitation of the giant plasmon resonance, and (b) large-energy-transfer processes that lead to multiple fragmentation of the molecule. Preliminary results of measurements on VUV photons emitted in these interactions are also presented

Energy Transfer between U(VI) and Eu(III) Ions Adsorbed on a Silica Surface

Energy Technology Data Exchange (ETDEWEB)

Park, K. K.; Cha, W.; Cho, H. R.; Im, H. J.; Jung, E. C.; Song, K. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2011-05-15

Understanding of chemical behavior of actinide in a groundwater flow is important for assessing the possibility of their migration with water flows in a radioactive waste disposal site. Uranium is ubiquitous in the environment and a major actinide in a nuclear fuel cycle. Americium and curium having isotopes of long half life are minor actinides in a spent fuel. If a minor actinide coexists with uranium in a groundwater flow, some interactions between them could be expected such as minor actinide adsorption onto uranium precipitates and competition with each other for an adsorption to a mineral surface site. Eu(III) ion is frequently used as a chemical analogue of Am(III) and Cm(III) ions in a migration chemistry. The luminescent spectra of U(VI) and Eu(III) ions show a dependency on the coordination symmetry around them, and the changes in intensity or bandwidth of spectra can yield valuable information on their local environment. The luminescent lifetime also strongly depends on the coordination environment, and its measurement is valuable in probe studies on micro-heterogeneous systems. The excited U(VI) ion can be quenched through Stern.Volmer process, hydrolysis of excited species, exciplex formation, electron transfer or energy transfer. In case of U(VI)-Eu(III) system, the interaction between two ions can be studied by measuring the effect of Eu(III) ion on the quenching of U(VI) ion luminescence. There are only a few investigations on the interaction between an excited U(VI) ion and a lanthanide(III) ion. In perchlorate solution, the energy transfer to Eu(III) ion occurred only in solutions of pH>3.87. In this study, the quenching of U(VI) luminescence by Eu(III) on a silica surface was measured. The results will be discussed on the basis of a chemical interaction between them

Operation of low-energy ion implanters for Si, N, C ion implantation into silicon and glassy carbon

International Nuclear Information System (INIS)

Carder, D.A.; Markwitz, A.

2009-01-01

This report details the operation of the low-energy ion implanters at GNS Science for C, N and Si implantations. Two implanters are presented, from a description of the components through to instructions for operation. Historically the implanters have been identified with the labels 'industrial' and 'experimental'. However, the machines only differ significantly in the species of ions available for implantation and sample temperature during implantation. Both machines have been custom designed for research purposes, with a wide range of ion species available for ion implantation and the ability to implant two ions into the same sample at the same time from two different ion sources. A fast sample transfer capability and homogenous scanning profiles are featured in both cases. Samples up to 13 mm 2 can be implanted, with the ability to implant at temperatures down to liquid nitrogen temperatures. The implanters have been used to implant 28 Si + , 14 N + and 12 C + into silicon and glassy carbon substrates. Rutherford backscattering spectroscopy has been used to analyse the implanted material. From the data a Si 30 C 61 N 9 layer was measured extending from the surface to a depth of about 77 ± 2 nm for (100) silicon implanted with 12 C + and 14 N + at multiple energies. Silicon and nitrogen ion implantation into glassy carbon produced a Si (40.5 %), C (38 %), N (19.5 %) and O (2%) layer centred around a depth of 50 ± 2 nm from the surface. (author). 8 refs., 20 figs

Development of negative heavy ion sources for plasma potential measurement

International Nuclear Information System (INIS)

Sasao, M.; Okabe, Y.; Fujisawa, A.; Iguchi, H.; Fujita, J.; Yamaoka, H.; Wada, M.

1991-10-01

A plasma sputter negative ion source was studied for its applicability to the potential measurement of a fusion plasma. Both the beam current density and the beam energy spread are key issues. Energy spectra of a self extracted Au - beam from the source were measured under the condition of a constant work function of the production surface. The full width of half maximum (FWHM) increases from 3 eV to 9 eV monotonically as the target voltage increases from 50 V to 300 V, independently from the target surface work function of 2.2 - 3 eV. (author)

Prospects for high energy heavy ion accelerators

International Nuclear Information System (INIS)

Leemann, C.

1979-03-01

The acceleration of heavy ions to relativistic energies (T greater than or equal to 1 GeV/amu) at the beam intensities required for fundamental research falls clearly in the domain of synchrotons. Up to date, such beams have been obtained from machines originally designed as proton acccelerators by means of modified RF-programs, improved vacuum and, most importantly, altered or entirely new injector systems. Similarly, for the future, substantial changes in synchrotron design itself are not foreseen, but rather the judicious application and development of presently known principles and technologies and a choice of parameters optimized with respect to the peculiarities of heavy ions. The low charge to mass ratio, q/A, of very heavy ions demands that superconducting magnets be considered in the interest of the highest energies for a given machine size. Injector brightness will continue to be of highest importance, and although space charge effects such as tune shifts will be increased by a factor q 2 /A compared with protons, advances in linac current and brightness, rather than substantially higher energies are required to best utilize a given synchrotron acceptance. However, high yeilds of fully stripped, very heavy ions demand energies of a few hundred MeV/amu, thus indicating the need for a booster synchrotron, although for entirely different reasons than in proton facilities. Finally, should we consider colliding beams, the high charge of heavy ions will impose severe current limitations and put high demands on system design with regard to such quantities as e.g., wall impedances or the ion induced gas desorption rate, and advanced concepts such as low β insertions with suppressed dispersion and very small crossing angles will be essential to the achievement of useful luminosities

Free-energy relationships in ion channels activated by voltage and ligand

Science.gov (United States)

Chowdhury, Sandipan

2013-01-01

Many ion channels are modulated by multiple stimuli, which allow them to integrate a variety of cellular signals and precisely respond to physiological needs. Understanding how these different signaling pathways interact has been a challenge in part because of the complexity of underlying models. In this study, we analyzed the energetic relationships in polymodal ion channels using linkage principles. We first show that in proteins dually modulated by voltage and ligand, the net free-energy change can be obtained by measuring the charge-voltage (Q-V) relationship in zero ligand condition and the ligand binding curve at highly depolarizing membrane voltages. Next, we show that the voltage-dependent changes in ligand occupancy of the protein can be directly obtained by measuring the Q-V curves at multiple ligand concentrations. When a single reference ligand binding curve is available, this relationship allows us to reconstruct ligand binding curves at different voltages. More significantly, we establish that the shift of the Q-V curve between zero and saturating ligand concentration is a direct estimate of the interaction energy between the ligand- and voltage-dependent pathway. These free-energy relationships were tested by numerical simulations of a detailed gating model of the BK channel. Furthermore, as a proof of principle, we estimate the interaction energy between the ligand binding and voltage-dependent pathways for HCN2 channels whose ligand binding curves at various voltages are available. These emerging principles will be useful for high-throughput mutagenesis studies aimed at identifying interaction pathways between various regulatory domains in a polymodal ion channel. PMID:23250866

Luminescence model with quantum impact parameter for low energy ions

CERN Document Server

Cruz-Galindo, H S; Martínez-Davalos, A; Belmont-Moreno, E; Galindo, S

2002-01-01

We have modified an analytical model of induced light production by energetic ions interacting in scintillating materials. The original model is based on the distribution of energy deposited by secondary electrons produced along the ion's track. The range of scattered electrons, and thus the energy distribution, depends on a classical impact parameter between the electron and the ion's track. The only adjustable parameter of the model is the quenching density rho sub q. The modification here presented, consists in proposing a quantum impact parameter that leads to a better fit of the model to the experimental data at low incident ion energies. The light output response of CsI(Tl) detectors to low energy ions (<3 MeV/A) is fitted with the modified model and comparison is made to the original model.

A miniaturised, nested-cylindrical electrostatic analyser geometry for dual electron and ion, multi-energy measurements

Energy Technology Data Exchange (ETDEWEB)

Bedington, Robert, E-mail: r.bedington@nus.edu.sg; Kataria, Dhiren; Smith, Alan

2015-09-01

The CATS (Cylindrical And Tiny Spectrometer) electrostatic optics geometry features multiple nested cylindrical analysers to simultaneously measure multiple energies of electron and multiple energies of ion in a configuration that is targeted at miniaturisation and MEMS fabrication. In the prototyped model, two configurations of cylindrical analyser were used, featuring terminating side-plates that caused particle trajectories to either converge (C type) or diverge (D type) in the axial direction. Simulations show how these different electrode configurations affect the particle focussing and instrument parameters; C-type providing greater throughputs but D-type providing higher resolving powers. The simulations were additionally used to investigate unexpected plate spacing variations in the as-built model, revealing that the k-factors are most sensitive to the width of the inter-electrode spacing at its narrowest point. - Highlights: • A new nested cylindrical miniaturised electrostatic analyser geometry is described. • “Converging” (C) and “diverging” (D) type channel properties are investigated. • C channels are shown to have greater throughputs and D greater resolving powers. • Plate factors are shown to be sensitive to the minimum in inter-electrode spacing.

QED corrections to the 4p-4d transition energies of copperlike heavy ions

International Nuclear Information System (INIS)

Chen, M. H.; Cheng, K. T.; Johnson, W. R.; Sapirstein, J.

2006-01-01

Quantum electrodynamic (QED) corrections to 4p-4d transition energies of several copperlike ions with Z=70-92 are calculated nonperturbatively in strong external fields to all orders in binding corrections. Dirac-Kohn-Sham potentials are used to account for screening and core-relaxation effects. For the 4p 1/2 -4d 3/2 transition in copperlike bismuth, thorium, and uranium, results are in good agreement with empirical QED corrections deduced from differences between transition energies obtained from recent high-precision electron-beam ion-trap measurements and those calculated with the relativistic many-body perturbation theory (RMBPT). These comparisons provide sensitive tests of QED corrections for high-angular-momentum states in many-electron heavy ions and illustrate the importance of core-relaxation corrections. Comparisons are also made with other theories and with experiments on the 4s-4p transition energies of high-Z Cu-like ions as accuracy checks of the present RMBPT and QED calculations

Electron capture in very low energy collisions of multicharged ions with H and D in merged beams

International Nuclear Information System (INIS)

Havener, C.C.; Meyer, F.W.; Phaneuf, R.A.

1991-01-01

An ion-atom merged-beams technique is being used to measure total absolute electron-capture cross sections for multicharged ions in collisions with H (or D) in the energy range between 0.1 and 1000 eV/amu. Comparison between experiment and theory over such a large energy range constitutes a critical test for both experiment and theory. Total capture cross-section measurements for O 3+ H(D) and O 5+ + H(D) are presented and compared to state selective and differential cross section calculations. Landau-Zener calculations show that for O 5+ the sharp increase in the measured cross section below 1 eV/amu is partly due to trajectory effects arising from the ion-induced dipole interaction between the reactants. 20 refs., 8 figs

Dependence of wavelength of Xe ion-induced rippled structures on the fluence in the medium ion energy range

Energy Technology Data Exchange (ETDEWEB)

Hanisch, Antje; Grenzer, Joerg [Institute of Ion Beam Physics and Materials Research, Dresden (Germany); Biermanns, Andreas; Pietsch, Ullrich [Institute of Physics, University of Siegen (Germany)

2010-07-01

Ion-beam eroded self-organized nanostructures on semiconductors offer new ways for the fabrication of high density memory and optoelectronic devices. It is known that wavelength and amplitude of noble gas ion-induced rippled structures tune with the ion energy and the fluence depending on the energy range, ion type and substrate. The linear theory by Makeev predicts a linear dependence of the ion energy on the wavelength for low temperatures. For Ar{sup +} and O{sub 2}{sup +} it was observed by different groups that the wavelength grows with increasing fluence after being constant up to an onset fluence and before saturation. In this coarsening regime power-law or exponential behavior of the wavelength with the fluence was monitored. So far, investigations for Xe ions on silicon surfaces mainly concentrated on energies below 1 keV. We found a linear dependence of both the ion energy and the fluence on the wavelength and amplitude of rippled structures over a wide range of the Xe{sup +} ion energy between 5 and 70 keV. Moreover, we estimated the ratio of wavelength to amplitude to be constant meaning a shape stability when a threshold fluence of 2.10{sup 17} cm{sup -2} was exceeded.

Beam-energy-dependent two-pion interferometry and the freeze-out eccentricity of pions measured in heavy ion collisions at the STAR detector

Science.gov (United States)

Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Anson, C. D.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Banerjee, A.; Beavis, D. R.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Borowski, W.; Bouchet, J.; Brandin, A. V.; Brovko, S. G.; Bültmann, S.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, L.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Chwastowski, J.; Codrington, M. J. M.; Contin, G.; Cramer, J. G.; Crawford, H. J.; Cui, X.; Das, S.; Davila Leyva, A.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Derradi de Souza, R.; Dhamija, S.; di Ruzza, B.; Didenko, L.; Dilks, C.; Ding, F.; Djawotho, P.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Engle, K. S.; Eppley, G.; Eun, L.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Fedorisin, J.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Gagliardi, C. A.; Gangadharan, D. R.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Gliske, S.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Haag, B.; Hamed, A.; Han, L.-X.; Haque, R.; Harris, J. W.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, B.; Huang, H. Z.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Kesich, A.; Khan, Z. H.; Kikola, D. P.; Kisel, I.; Kisiel, A.; Koetke, D. D.; Kollegger, T.; Konzer, J.; Koralt, I.; Kosarzewski, L. K.; Kotchenda, L.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; LeVine, M. J.; Li, C.; Li, W.; Li, X.; Li, X.; Li, Y.; Li, Z. M.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, G. L.; Ma, Y. G.; Madagodagettige Don, D. M. M. D.; Mahapatra, D. P.; Majka, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; McShane, T. S.; Minaev, N. G.; Mioduszewski, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nigmatkulov, G.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Ohlson, A.; Okorokov, V.; Oldag, E. W.; Olvitt, D. L.; Pachr, M.; Page, B. S.; Pal, S. K.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Pawlik, B.; Pei, H.; Perkins, C.; Peryt, W.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Poniatowska, K.; Porter, J.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Pujahari, P. R.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Riley, C. K.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ross, J. F.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sangaline, E.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Singaraju, R. N.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Solanki, D.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stevens, J. R.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Sun, X.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Svirida, D. N.; Symons, T. J. M.; Szelezniak, M. A.; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Trzeciak, B. A.; Tsai, O. D.; Turnau, J.; Ullrich, T.; Underwood, D. G.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Vanfossen, J. A.; Varma, R.; Vasconcelos, G. M. S.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Vossen, A.; Wada, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J. S.; Wang, X. L.; Wang, Y.; Wang, Y.; Webb, G.; Webb, J. C.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Xiao, Z.; Xie, W.; Xin, K.; Xu, H.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y.; Xu, Z.; Yan, W.; Yang, C.; Yang, Y.; Yang, Y.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zawisza, Y.; Zbroszczyk, H.; Zha, W.; Zhang, J. B.; Zhang, J. L.; Zhang, S.; Zhang, X. P.; Zhang, Y.; Zhang, Z. P.; Zhao, F.; Zhao, J.; Zhong, C.; Zhu, X.; Zhu, Y. H.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

2015-07-01

We present results of analyses of two-pion interferometry in Au +Au collisions at √{sNN}=7.7 , 11.5, 19.6, 27, 39, 62.4, and 200 GeV measured in the STAR detector as part of the BNL Relativistic Heavy Ion Collider Beam Energy Scan program. The extracted correlation lengths (Hanbury-Brown-Twiss radii) are studied as a function of beam energy, azimuthal angle relative to the reaction plane, centrality, and transverse mass (mT) of the particles. The azimuthal analysis allows extraction of the eccentricity of the entire fireball at kinetic freeze-out. The energy dependence of this observable is expected to be sensitive to changes in the equation of state. A new global fit method is studied as an alternate method to directly measure the parameters in the azimuthal analysis. The eccentricity shows a monotonic decrease with beam energy that is qualitatively consistent with the trend from all model predictions and quantitatively consistent with a hadronic transport model.

Energy Transfer Efficiency from ZnO-Nanocrystals to Eu3+ Ions Embedded in SiO₂ Film for Emission at 614 nm.

Science.gov (United States)

Mangalam, Vivek; Pita, Kantisara

2017-08-10

In this work, we study the energy transfer mechanism from ZnO nanocrystals (ZnO-nc) to Eu 3+ ions by fabricating thin-film samples of ZnO-nc and Eu 3+ ions embedded in a SiO₂ matrix using the low-cost sol-gel technique. The time-resolved photoluminescence (TRPL) measurements from the samples were analyzed to understand the contribution of energy transfer from the various ZnO-nc emission centers to Eu 3+ ions. The decay time obtained from the TRPL measurements was used to calculate the energy transfer efficiencies from the ZnO-nc emission centers, and these results were compared with the energy transfer efficiencies calculated from steady-state photoluminescence emission results. The results in this work show that high transfer efficiencies from the excitonic and Zn defect emission centers is mostly due to the energy transfer from ZnO-nc to Eu 3+ ions which results in the radiative emission from the Eu 3+ ions at 614 nm, while the energy transfer from the oxygen defect emissions is most probably due to the energy transfer from ZnO-nc to the new defects created due to the incorporation of the Eu 3+ ions.

P.I.A.F.E project: long distance transport of low energy exotic ions; Projet P.I.A.F.E: transport d`ions exotiques de basse energie sur longue distance

Energy Technology Data Exchange (ETDEWEB)

Nibart, V.

1996-01-17

The aim of the PIAFE project is the long distance (400 m) transport of a low energy radioactive ion beam from the ILL (Institut Laue Langevin) to the ISN (Institut des Sciences Nucleaires) of Grenoble (France). The production, extraction, ionization and mass separation of ions is performed by the ILL, while the transformation of ions into multicharged ions, their stripping and acceleration is carried out at the ISN. Theoretical and experimental studies for a simple an original guidance solution have shown that such a long transport, even delicate, should not encounter any major difficulty. The main objectives of this thesis is the technical realization of a 18 m section of this transport line. The problem of supports and focalizing elements alignment has been solved together with the other problems such as: the central trajectory deviation due to alignment defects and to the Earth`s magnetic field; the particle losses due to charge exchange with the residual gas and the emittance increase by Coulomb scattering. It has been demonstrated that a 90% transmission can be obtained using a 25 keV energy and a 10{sup -7} mbar vacuum. Experimental measurements using a rubidium ion source have allowed to validate a theoretical model of emittance increase due to the residual gas-ions interactions. The increase of emittance with respect to the pressure has been measured using four residual gases of different mass. (J.S.). 29 refs., 61 figs., 19 tabs., 8 photos., 4 appends.

Energy dissipation on ion-accelerator grids during high-voltage breakdown

International Nuclear Information System (INIS)

Menon, M.M.; Ponte, N.S.

1981-01-01

The effects of stored energy in the system capacitance across the accelerator grids during high voltage vacuum breakdown are examined. Measurements were made of the current flow and the energy deposition on the grids during breakdown. It is shown that only a portion (less than or equal to 40 J) of the total stored energy (congruent to 100 J) is actually dissipated on the grids. Most of the energy is released during the formation phase of the vacuum arc and is deposited primarily on the most positive grid. Certain abnormal situations led to energy depositions of about 200 J on the grid, but the ion accelerator endured them without exhibiting any deterioration in performance

Review of high excitation energy structures in heavy ion collisions: target excitations and three body processes

International Nuclear Information System (INIS)

Frascaria, N.

1987-09-01

A review of experimental results on high excitation energy structures in heavy ion inelastic scattering is presented. The contribution to the spectra of the pick-up break-up mechanism is discussed in the light of the data obtained with light heavy ion projectiles. Recent results obtained with 40 Ar beams at various energies will show that target excitations contribute strongly to the measured cross section

Ion-beam doping of GaAs with low-energy (100 eV) C + using combined ion-beam and molecular-beam epitaxy

Science.gov (United States)

Iida, Tsutomu; Makita, Yunosuke; Kimura, Shinji; Winter, Stefan; Yamada, Akimasa; Fons, Paul; Uekusa, Shin-ichiro

1995-01-01

A combined ion-beam and molecular-beam-epitaxy (CIBMBE) system has been developed. This system consists of an ion implanter capable of producing ions in the energy range of 30 eV-30 keV and conventional solid-source MBE. As a successful application of CIBMBE, low-energy (100 eV) carbon ion (C+) irradiation during MBE growth of GaAs was carried out at substrate temperatures Tg between 500 and 590 °C. C+-doped layers were characterized by low-temperature (2 K) photoluminescence (PL), Raman scattering, and van der Pauw measurements. PL spectra of undoped GaAs grown by CIBMBE revealed that unintentional impurity incorporation into the epilayer is extremely small and precise doping effects are observable. CAs acceptor-related emissions such as ``g,'' [g-g], and [g-g]β are observed and their spectra are significantly changed with increasing C+ beam current density Ic. PL measurements showed that C atoms were efficiently incorporated during MBE growth by CIBMBE and were optically well activated as an acceptor in the as-grown condition even for Tg as low as 500 °C. Raman measurement showed negligible lattice damage of the epilayer bombarded with 100 eV C+ with no subsequent heat treatment. These results indicate that contamination- and damage-free impurity doping without postgrowth annealing can be achieved by the CIBMBE method.

Ion-beam doping of GaAs with low-energy (100 eV) C(+) using combined ion-beam and molecular-beam epitaxy

Science.gov (United States)

Lida, Tsutomu; Makita, Yunosuke; Kimura, Shinji; Winter, Stefan; Yamada, Akimasa; Fons, Paul; Uekusa, Shin-Ichiro

1995-01-01

A combined ion-beam and molecular-beam-epitaxy (CIBMBE) system has been developed. This system consists of an ion implanter capable of producing ions in the energy range of 30 eV - 30 keV and conventional solid-source MBE. As a successful application of CIBMBE, low-energy (100 eV) carbon ion (C(+)) irradiation during MBE growth of GaAs was carried out at substrate temperatures T(sub g) between 500 and 590 C. C(+)-doped layers were characterized by low-temperature (2 K) photoluminescence (PL), Raman scattering, and van der Pauw measurements. PL spectra of undoped GaAs grown by CIBMBE revealed that unintentional impurity incorporation into the epilayer is extremely small and precise doping effects are observable. C(sub As) acceptor-related emissions such as 'g', (g-g), and (g-g)(sub beta) are observed and their spectra are significantly changed with increasing C(+) beam current density I(sub c). PL measurements showed that C atoms were efficiently incorporated during MBE growth by CIBMBE and were optically well activated as an acceptor in the as-grown condition even for T(sub g) as low as 500 C. Raman measurement showed negligible lattice damage of the epilayer bombarded with 100 eV C(+) with no subsequent heat treatment. These results indicate that contamination- and damage-free impurity doping without postgrowth annealing can be achieved by the CIBMBE method.

Importance of ion energy on SEU in CMOS SRAMs

Energy Technology Data Exchange (ETDEWEB)

Dodd, P.E.; Shaneyfelt, M.R.; Sexton, F.W.; Hash, G.L.; Winokur, P.S. [Sandia National Labs., Albuquerque, NM (United States); Musseau, O.; Leray, J.L. [CEA-DAM, Bruyeres-le-Chatel (France)

1998-03-01

The single-event upset (SEU) responses of 16 Kbit to 1 Mbit SRAMs irradiated with low and high-energy heavy ions are reported. Standard low-energy heavy ion tests appear to be sufficiently conservative for technologies down to 0.5 {micro}m.

Low energy helium ion irradiation induced nanostructure formation on tungsten surface

International Nuclear Information System (INIS)

Al-Ajlony, A.; Tripathi, J.K.; Hassanein, A.

2017-01-01

We report on the low energy helium ion irradiation induced surface morphology changes on tungsten (W) surfaces under extreme conditions. Surface morphology changes on W surfaces were monitored as a function of helium ion energy (140–300 eV), fluence (2.3 × 10 24 –1.6 × 10 25 ions m −2 ), and flux (2.0 × 10 20 –5.5 × 10 20 ion m −2 s −1 ). All the experiments were performed at 900° C. Our study shows significant effect of all the three ion irradiation parameters (ion flux, fluence, and energy) on the surface morphology. However, the effect of ion flux is more pronounced. Variation of helium ion fluence allows to capture the very early stages of fuzz growth. The observed fuzz growth and morphology changes were understood in the realm of various possible phenomena. The study has relevance and important impact in the current and future nuclear fusion applications. - Highlights: •Reporting formation of W nanostructure (fuzz) due to low energy He ion beam irradiation. •Observing the very early stages for the W-Fuzz formation. •Tracking the surface morphological evolution during the He irradiation. •Discussing in depth our observation and drawing a possible scenario that explain this phenomenon. •Studying various ions irradiation parameters such as flux, fluence, and ions energy.

Angular correlations and fragmentation in intermediate energy heavy ion collisions

International Nuclear Information System (INIS)

Kristiansson, Anders.

1990-05-01

Intermediate energy heavy-ion collisions have been studied from 35 A MeV up to 94 A MeV at various accelerators. Angular correlations between light particles and detection of projectile- and target-fragments have been used to investigate the reaction mechanisms in this transition region between low- and high energy. An excess of correlations is observed in the particle-particle elastic scattering plane. This excess increases with particle mass and can be understood in terms of momentum conservation. The fragmentation measurements gives an indication that both energy and momentum transfer to the spectator volumes does occur. (author)

Coulomb-driven energy boost of heavy ions for laser-plasma acceleration.

Science.gov (United States)

Braenzel, J; Andreev, A A; Platonov, K; Klingsporn, M; Ehrentraut, L; Sandner, W; Schnürer, M

2015-03-27

An unprecedented increase of kinetic energy of laser accelerated heavy ions is demonstrated. Ultrathin gold foils have been irradiated by an ultrashort laser pulse at a peak intensity of 8×10^{19}  W/  cm^{2}. Highly charged gold ions with kinetic energies up to >200  MeV and a bandwidth limited energy distribution have been reached by using 1.3 J laser energy on target. 1D and 2D particle in cell simulations show how a spatial dependence on the ion's ionization leads to an enhancement of the accelerating electrical field. Our theoretical model considers a spatial distribution of the ionization inside the thin target, leading to a field enhancement for the heavy ions by Coulomb explosion. It is capable of explaining the energy boost of highly charged ions, enabling a higher efficiency for the laser-driven heavy ion acceleration.

Mass-spectrometric study of ion clustering in alkali-metal hydroxide vapor: cluster-ion energy and structural characteristics

International Nuclear Information System (INIS)

Kudin, L.S.; Butman, M.F.; Krasnov, K.S.

1986-01-01

Various positive and negative ions have been recorded in the equilibrium vapors from alkali-metal hydroxides: M/sup +/-/, OH - , O - , MO - , MOH - , and X/sup +/-/ (MOH)/sub n/, where X = M/sup +/-/, OH - , n = 1-6. The equilibrium constants have been measured for X/sup +/-/(MOH)/sub n/ = x/sup +/-/ + nMOH(k), n = 1-3, and the enthalpies of reaction have been determined, from which the enthalpies of formation and dissociation energies of X/sup +/-/ (MOH)/sub n/ have been calculated. The relative stabilities of the ions in the series from Na to Cs are examined

Effect of energy selection on quantitative analysis in secondary ion microanalysis

International Nuclear Information System (INIS)

Steele, I.M.; Solberg, T.N.; Smith, J.V.; Clayton, R.N.; Hutcheon, I.D.

1977-01-01

Systematic change of voltage on the components of the secondary ion (SI) extraction system of our AEI-IM20 ion microprobe produced major changes of relative intensities of secondary ions passing through the mass spectrometer. The repeller, which bends the SI beam through about 60 0 , has the greatest effect, and can be used to plot the energy distribution. The extractor and the deflecting and focusing components have smaller but significant effects. Because low-energy secondary ions have a near-symmetrical distribution, whereas high-energy ones have an assymetric distribution favoring high energies, tuning of the acceptance band to higher energy reduces interference from low-energy ions, which tend to be unwanted molecular ions, at the expense of reduced transmission. Tuning to lower energy increases interference but gives higher transmission. The former condition is desirable for instruments restricted to low mass resolution, whereas both conditions are valuable for instruments adjustable for both high and low mass resolution. Other important factors are (a) sensitivity to surface irregularities which perturb SI energy collection, and (b) change in derived 'temperatures' from thermodynamic sputtering models merely from tuning the energy acceptance band. Careful attention to the above factors yielded reproducible SI ratios for the binary series of plagioclase feldspars. (Auth.)