SPUTTERING OF GOLD AND COPPER SURFACES UNDER LOW ENERGY CESIUM IONS

2021 ◽  
Author(s):  
UZAIR AHMED ◽  
MOHSAN JELANI ◽  
NAJAM UL HASSAN ◽  
MUHAMMAD NAEEM ◽  
TAHIR ZAMAN ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Energy Range ◽  
Power Law ◽  
Negative Ions ◽  
Gold Clusters ◽  
Low Energy ◽  
Cluster Ions ◽  
Mass Analyzer ◽  
Cesium Ions ◽  
Sputtering Yield

To use gold and copper ions for ion implantation through 1-MV pelletron accelerator, gold and copper targets were bombarded with low energy cesium ions applying source of negative ions by cesium sputtering (SNICS). This work aims to investigate the cluster dynamics of these noble metals in a low energy range so that optimized data can be obtained for the use of these cluster ions in ion implantation. Negative ions including monomers and clusters of both metals were detected which were mass analyzed. Cu clusters up to Cu[Formula: see text] and gold clusters up to Au[Formula: see text] were emitted. The minimum energy of cesium ions to produce enough cluster ions so that they could be detected by a mass analyzer has been determined. The data was analyzed to measure sputtering yield, total sputtering yield and normalized number density of different sputtered species. In this energy range, the sputtering behaviors of Cu remain almost constant but in the case of Au there is a slight increase in cluster sputtering probability with an increase in incident ion energy. The sputtering yield of clusters decreases according to the power-law, i.e. [Formula: see text]. Power law exponent in the case of copper has an average value of [Formula: see text] whereas exponent in the case of gold clusters changes from 3.5 to 6.

scholarly journals Detection of the Geminga pulsar with MAGIC hints at a power-law tail emission beyond 15 GeV

2020 ◽  
Vol 643 ◽  
pp. L14
Author(s):  
◽  
V. A. Acciari ◽  
S. Ansoldi ◽  
L. A. Antonelli ◽  
A. Arbet Engels ◽  
...  
Keyword(s):  
Energy Range ◽  
Power Law ◽  
Gamma Ray ◽  
Low Energy ◽  
Significance Level ◽  
Inverse Compton Scattering ◽  
Curvature Radiation ◽  
Sensitivity Range ◽  
Inverse Compton ◽  
First Time

We report the detection of pulsed gamma-ray emission from the Geminga pulsar (PSR J0633+1746) between 15 GeV and 75 GeV. This is the first time a middle-aged pulsar has been detected up to these energies. Observations were carried out with the MAGIC telescopes between 2017 and 2019 using the low-energy threshold Sum-Trigger-II system. After quality selection cuts, ∼80 h of observational data were used for this analysis. To compare with the emission at lower energies below the sensitivity range of MAGIC, 11 years of Fermi-LAT data above 100 MeV were also analysed. From the two pulses per rotation seen by Fermi-LAT, only the second one, P2, is detected in the MAGIC energy range, with a significance of 6.3σ. The spectrum measured by MAGIC is well-represented by a simple power law of spectral index Γ = 5.62 ± 0.54, which smoothly extends the Fermi-LAT spectrum. A joint fit to MAGIC and Fermi-LAT data rules out the existence of a sub-exponential cut-off in the combined energy range at the 3.6σ significance level. The power-law tail emission detected by MAGIC is interpreted as the transition from curvature radiation to Inverse Compton Scattering of particles accelerated in the northern outer gap.

The Use of Negative Ions in Ion Implantation with Tandem High Energy Accelerators

1993 ◽  
Vol 316 ◽  
Author(s):  
John P. O'Connor ◽  
Nobuhiro Tokoro
Keyword(s):  
Ion Implantation ◽  
Negative Ions ◽  
Beam Current ◽  
High Energy ◽  
Low Energy ◽  
Energy Beam ◽  
System Changes ◽  
Low Energies ◽  
Beam Currents ◽  
Medium Dose

ABSTRACTSince the introduction of the G1500 ion implanter, the use of tandem accelerators in production ion implantation systems has become well established. However, the beam currents which are attainable at present at low energies (< 200 keV) are suitable for only low and low-end medium dose implants. An approach to increase low energy beam currents in d.c. tandem accelerators is presented. Specifically, the use of negative ions which have been generated in the injector are transported to the end station and implanted into the wafers. In this work, beam current measurements performed using the G1500 system are presented for the typical semiconductor dopants. System changes which are necessary to accomplish implants with negative ions are discussed. A comparison of sheet resistances and uniformities measured with both positive and negative ions at the same energy and from the same G1500 system are presented. SIMS profile measurements of implants with both positive and negative ions at the same energy are also presented.

Low-energy Bremsstrahlung X-ray spectra from a stable auroral arc

1969 ◽  
Vol 47 (21) ◽  
pp. 2427-2430 ◽  
Author(s):  
B. G. Wilson ◽  
A. J. Baxter ◽  
D. W. Green
Keyword(s):  
Energy Range ◽  
Power Law ◽  
Spectral Characteristics ◽  
Low Energy ◽  
X Rays ◽  
X Ray ◽  
Rocket Experiment

During a rocket experiment launched to investigate cosmic X rays, the directional features and spectral characteristics of X rays from an auroral arc have been determined in the 1.6 to 10 keV energy range. The spectrum was best represented by a power law of slope −3.365 ± 0.07.

A device for controlling the energy of ionizing electrons in the low-energy range designed to form a complete mass spectrum of negative ions using a quadrupole mass spectrometer

2020 ◽  
Vol 86 (4) ◽  
pp. 12-20
Author(s):  
A. G. Terentyev ◽  
R. V. Khatymov ◽  
A. V. Maltsev
Keyword(s):  
Mass Spectrum ◽  
Energy Range ◽  
Electron Energy ◽  
Mass Spectrometer ◽  
Mass Spectra ◽  
Negative Ions ◽  
Mass Spectrometric ◽  
Low Energy ◽  
Quadrupole Mass ◽  
Positive Ions

Operation with positive ions formed from the impact of high energy electrons (usually 70 eV, which exceeds the ionization energy of the molecules) is a standard mode for mass spectrometric detectors of most gas chromatography-mass spectrometric complexes (GC/MS) in the basic configuration. At the same time, we have shown that the option of setting the energy of ionizing electrons (maintained in the design of some serial devices) within the pre-ionization region also allows one to obtain mass spectra of negative ions (NI) which, in turn, significantly expands the analytical potential of standard equipment. The formation of NI occurs in the low-energy range of 0 – 15 eV due to resonant capture of electrons by molecules (REC). In contrast to positive ions, the intensity of NI formation sharply (resonantly) depends on the electron energy and this dependence is characteristic of each chemical compound. Both the relative intensity of the mass-peaks and, in general, the ionic composition of the formed mass spectrum of NI significantly depend on the electron energy. The problem of choosing the optimal energy of ionizing electrons providing the same efficiency of mass-spectrometric determination of all components of complex mixtures of dissimilar compounds is also associated with the features of negative ion formation during chromatography-mass spectrometric analysis. To address the problem, we propose a technique providing generation of complete (in NI composition and intensities) mass spectra of NI through repeated variation of the energy of ionizing electrons in a given range of 0 – 10 eV. Technical implementation of the technique [1] was carried out at the Design Bureau «Chromatec «(Yoshkar Ola, Russia) in the form of a special electronic device, which was tested in pilot operation as part of the gas chromatograph complex with a quadrupole mass spectrometer «Chromatec». We describe the principle of operation of the device and present the results of tests.

scholarly journals Charmed and bottomed hadronic cross sections from a statistical model

2020 ◽  
Vol 56 (9) ◽  
Author(s):  
Gábor Balassa ◽  
György Wolf
Keyword(s):  
Statistical Model ◽  
Energy Range ◽  
Cross Sections ◽  
Heavy Quarks ◽  
Open Charm ◽  
Low Energy ◽  
Final State ◽  
Proton Antiproton ◽  
Proton Proton

Abstract In this work, we extended our statistical model with charmed and bottomed hadrons, and fit the quark creational probabilities for the heavy quarks, using low energy inclusive charmonium and bottomonium data. With the finalized fit for all the relevant types of quarks (up, down, strange, charm, bottom) at the energy range from a few GeV up to a few tens of GeV’s, the model is now considered complete. Some examples are also given for proton–proton, pion–proton, and proton–antiproton collisions with charmonium, bottomonium, and open charm hadrons in the final state.

Special Aspects of High-Intensity Low-Energy Ion Implantation

2021 ◽  
Author(s):  
A. I. Ryabchikov ◽  
A. I. Ivanova ◽  
O. S. Korneva ◽  
D. O. Sivin
Keyword(s):  
Ion Implantation ◽  
High Intensity ◽  
Low Energy

Carbon Nitride Film Formation by Low Energy Positive and Negative Ion Beam Deposition

1996 ◽  
Vol 438 ◽  
Author(s):  
N. Tsubouchi ◽  
Y. Horino ◽  
B. Enders ◽  
A. Chayahara ◽  
A. Kinomura ◽  
...  
Keyword(s):  
Carbon Nitride ◽  
Rutherford Backscattering Spectrometry ◽  
Ion Beam ◽  
High Vacuum ◽  
Negative Ions ◽  
Low Energy ◽  
Ultra High Vacuum ◽  
Negative Ion ◽  
Nitride Film ◽  
Ion Energy

AbstractUsing a newly developed ion beam apparatus, PANDA (Positive And Negative ions Deposition Apparatus), carbon nitride films were prepared by simultaneous deposition of mass-analyzed low energy positive and negative ions such as C2-, N+, under ultra high vacuum conditions, in the order of 10−6 Pa on silicon wafer. The ion energy was varied from 50 to 400 eV. The film properties as a function of their beam energy were evaluated by Rutherford Backscattering Spectrometry (RBS), Fourier Transform Infrared spectroscopy (FTIR) and Raman scattering. From the results, it is suggested that the C-N triple bond contents in films depends on nitrogen ion energy.

Big channeling effects at low-energy ion implantation in silicon

1986 ◽  
Vol 97 (2) ◽  
pp. K135-K139 ◽  
Author(s):  
J. Bollmann ◽  
H. Klose ◽  
A. Mertens
Keyword(s):  
Ion Implantation ◽  
Low Energy
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