Investigation of conical anode – disc cathode ion source

2018 ◽  
Vol 96 (2) ◽  
pp. 194-201
Author(s):  
S. Abdel Samed ◽  
S.I. Radwan ◽  
H. El-Khabeary

An axial direct-current conical anode – disc cathode ion source has been designed, constructed, and operated. The electrical discharge and the output ion beam characteristics are measured using nitrogen gas. It is found that at the optimum dimensions, pressure equal to 4.5 × 10−5 mm Hg and discharge current equal to 250 μA, a maximum output ion beam current equal to 91 μA can be obtained. A comparison between the experimental results and theoretical calculations of the output ion beam current values at the optimum dimensions and operating parameters for different discharge current of conical anode and disc cathode ion source using nitrogen gas is determined. It is found that a good agreement exists between the experimental results and theoretical calculations.

2013 ◽  
Vol 1575 ◽  
Author(s):  
Mitsuaki Takeuchi ◽  
Takuya Hamaguchi ◽  
Hiromichi Ryuto ◽  
Gikan H Takaoka

ABSTRACTIonic liquid (IL) ion sources with different emitter tip materials and tip numbers were developed and examined on ion beam characteristics with respect to its ILs wettability. As a result of ion current measurements, the most stable emission current was obtained for the graphite emitter tip and the ion current increased with increase of the tip number. The results indicate that the emitter wettability corresponding to the supplying flow rate and the number of emission site play an important role to stabilize and increase the beam current.


2017 ◽  
Vol 95 (5) ◽  
pp. 457-463 ◽  
Author(s):  
A.G. Helal ◽  
H. El-Khabeary ◽  
S.I. Radwan

In this work, design and construction of a DC cold cathode Penning ion source is described. It consists of cylindrical hollow anode and two movable disc cathodes that are placed symmetrically at two ends of the anode. The electrical discharge and the output ion beam characteristics of the ion source are measured using argon gas. It is found that the optimum dimensions of anode–cathode distance, ion exit aperture diameter, and ion exit aperture – Faraday cup distance are equal to 8, 1.5, and 30 mm, respectively. The ion source efficiency was calculated at discharge current equal to 1.2 mA, different anode–cathode distances and pressures using argon gas. It is found that at anode–cathode distance equal to 8 mm and pressure equal to 7 × 10−4 mmHg, a maximum ion source efficiency equal to 27.1% can be obtained. The surface hardness of molybdenum specimen is measured after exposure to argon ion beam for two hours at pressure equal to 7 × 10−4 mmHg, discharge voltage equal to 3.5 kV, discharge current equal to 0.6 mA, and output ion beam current equal to 165 μA using argon gas. It is found that the surface hardness of molybdenum specimen is decreased by a factor of 24.2%.


2009 ◽  
Vol 26 (8) ◽  
pp. 082901 ◽  
Author(s):  
Zou Gui-Qing ◽  
Lei Guang-Jiu ◽  
Jiang Shao-Feng ◽  
Cao Jian-Yong ◽  
Yu Li-Ming ◽  
...  

In s.i.m.s. the sample surface is ion bombarded and the emitted secondary ions are mass analysed. When used in the static mode with very low primary ion beam current densities (10 -11 A/mm 2 ), the technique analyses the outermost atomic layers with the following advantages (Benninghoven 1973, I975): the structural—chemical nature of the surface may be deduced from the masses of the ejected ionized clusters of atoms; detection of hydrogen and its compounds is possible; sensitivity is extremely high (10 -6 monolayer) for a number of elements. Composition profiles are obtained by increasing the primary beam current density (dynamic mode) or by combining the technique in the static mode with ion beam machining with a separate, more powerful ion source. The application of static s.i.m.s. in metallurgy has been explored by analysing a variety of alloy surfaces after fabrication procedures in relation to surface quality and subsequent performance. In a copper—silver eutectic alloy braze it was found that the composition of the solid surface depended markedly on its pretreatment. Generally there was a surface enrichment of copper relative to silver in melting processes while sawing and polishing enriched the surface in silver


1989 ◽  
Vol 157 ◽  
Author(s):  
Wang Xi ◽  
Zhou Jiankun ◽  
Chen Youshan ◽  
Liu Xianghuai ◽  
Zou Shichang

ABSTRACTA Monte-Carlo computer simulation has been performed to describe, at atomic level, the growth of titanium nitride films formed by ion beam enhanced deposition (IBED). The simulation is based on a random target, fixed free path of moving particles and binary collisions. An alternate process of deposition of titanium atoms and implantation of nitrogen ions is applied instead of the actual continuous and synchronous process of IBED. According to the actual conditions, the adsorption of nitrogen gas, which is leaked out from the ion source, at the fresh titanium layer surface has been considered. In addition, the change of the composition profile and the density profile during film growth is taken into account. It is demonstrated that the width of the intermixed region between the film and substrate increases with the increase of the atomic arrival ratio, R, of implanted nitrogen ions to deposited titanium atoms. When the titanium deposition rate is low, the nitrogen concentration of the film is relatively insensitive to R, indicating that a dominant contribution to the nitrogen concentration is derived from the nitrogen gas leaked out from the ion source. The results obtained in this study are in agreement with the experimental measurements.


1962 ◽  
Vol 33 (12) ◽  
pp. 1338-1339 ◽  
Author(s):  
Edwin M. Kellogg ◽  
Karl E. Eklund

2015 ◽  
Vol 7 (12) ◽  
pp. 945-949
Author(s):  
Boo Ki Min ◽  
Ju Sung Kim ◽  
Seung Ju Lim ◽  
Hyun OH Joo ◽  
Sang Jung Ahn ◽  
...  

Radiocarbon ◽  
2010 ◽  
Vol 52 (2) ◽  
pp. 310-318 ◽  
Author(s):  
Yusuke Yokoyama ◽  
Mamito Koizumi ◽  
Hiroyuki Matsuzaki ◽  
Yosuke Miyairi ◽  
Naohiko Ohkouchi

We have developed accelerator mass spectrometry (AMS) measurement techniques for ultra small-size samples ranging from 0.01 to 0.10 mg C with a new type of MC-SNICS ion source system. We can generate 4 times higher ion beam current intensity for ultra-small samples by optimization of graphite position in the target holder with the new ionizer geometry. CO2 gas graphitized in the newly developed vacuum line is pressed to a depth of 1.5 mm from the front of the target holder. This is much deeper than the previous position at 0.35 mm depth. We measured 12C4+ beam currents generated by small standards and ion beam currents (15–30 μA) from the targets in optimized position, lasting 20 min for 0.01 mg C and 65 min for 0.10 mg C. We observed that the measured 14C/12C ratios are unaffected by the difference of ion beam currents ranging from 5 to 30 μA, enabling measurement of ultra-small samples with high precision. Examination of the background samples revealed 1.1 μg of modern and 1 μg of dead carbon contaminations during target graphite preparation. We make corrections for the contamination from both the modern and background components. Reduction of the contamination is necessary for conducting more accurate measurement.


2003 ◽  
Vol 02 (04n05) ◽  
pp. 375-379 ◽  
Author(s):  
A. A. TSENG ◽  
B. LEELADHARAN ◽  
B. LI ◽  
I. INSUA ◽  
C. D. CHEN

The capability of using Focused Ion Beam (FIB) for milling microchannels is experimentally and theoretically investigated. Microchannel structures are fabricated by a NanoFab 150 FIB machine, using an Arsenic (As2+) ion source. A beam current of 5 pA at 90 keV accelerating energy is used. Several microchannel patternings are milled at various dwell times at pixel spacing of 14.5 nm on top of a 60 nm gold-coated silicon wafer. An analytical/numerical model is developed to predict the FIB milling behavior. By comparing with the experimental measurements, the model predictions have been demonstrated to be reliable for guiding and controlling the milling processes.


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