Calibration of a neutral particle beam source with the novel Absolute Beam Monitor

Mapping Intimacies ◽

10.5194/egusphere-egu21-956 ◽

2021 ◽

Author(s):

Jonathan Gasser ◽

André Galli ◽

Peter Wurz

Keyword(s):

Energy Range ◽

Beam Energy ◽

Neutral Atom ◽

Neutral Particle ◽

Ion Beam ◽

Neutral Beam ◽

Test Facility ◽

Beam Source ◽

Energetic Neutral Atom ◽

Beam Monitor

The energetic neutral atom detection instrument IMAP-Lo is part of the scientific payload of the upcoming Interstellar Mapping and Acceleration Probe (IMAP) mission by NASA and is designed to analyse interstellar neutral and heliospheric Energetic Neutral Atom fluxes and their composition for energies from 1000 eV down to 10&#160;eV. IMAP is dedicated to extend our knowledge of the local interstellar medium (LISM) and its interaction with the solar magnetic field and the heliosphere. Most importantly, H, He, O and Ne ENAs will be analysed.Calibration and testing of IMAP-Lo is planned in MEFISTO, a unique laboratory test facility for ion and neutral particle instruments at the University of Bern, which can provide the required neutral atom beams. In MEFISTO we have a microwave-induced plasma ion source for beam energies up to 100&#160;keV/q. The ion beam can be converted to a neutral beam in the energy range 10 eV &#8211; 3 keV with a removable ion beam neutralizer with decelerating the ion beam first and subsequent neutralisation via surface reflection. It comes with an estimated beam energy reduction of 15&#160;% and energy-dependent transmission. The neutral beam flux into the test chamber therefore depends on the ion beam energy, intensity and species. To improve the calibration process for ENA space instruments such as IMAP-Lo, it is important to measure the neutral beam flux and energy in the test facility.The Absolute Beam Monitor (ABM) is a novel laboratory device developed for absolute neutral particle flux measurements and energy determination of neutral atom beams. The ABM takes advantage of secondary electron emission during surface scattering of incident neutral atoms off a highly polished tungsten plate. The effective rate of neutrals is inferred from detecting secondary electrons and reflected atoms in two electron multipliers as well as its coincidence signal rate. Time difference of the two signals yields the neutrals energy. To date, the ABM is the only device to measure absolute fluxes of neutral atoms in this energy range.Measurements of the neutral beam source in MEFISTO have been performed for several species using the ABM to determine the relation between the effective neutral atom flux and the primary ion beam current at the charge conversion surface, as well as the neutral beam energy, for ion energies from 1000&#160;eV down to 10&#160;eV.

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Absolute Beam Monitor: a device to measure the absolute particle flux of a neutral atom beam – prototype development and testing

10.5194/egusphere-egu2020-3302 ◽

2020 ◽

Author(s):

Jonathan Gasser ◽

Peter Wurz ◽

André Galli

Keyword(s):

Particle Flux ◽

Neutral Atom ◽

Neutral Particle ◽

Ion Beam ◽

Neutral Atoms ◽

Atom Beam ◽

Prototype Development ◽

Calibration Methods ◽

Beam Monitor ◽

The Absolute

The Interstellar Mapping and Acceleration Probe (IMAP) mission by NASA, to be launched in 2024, aims at deepening the understanding of the solar heliosphere by verifying and extending the results obtained from the Interstellar Boundary Explorer (IBEX). IMAP-Lo is a neutral atom imaging and analysis instrument to be used to measure heliospheric Energetic Neutral Atoms (ENAs), mainly H, He, O, Ne in the energy range from 10&#160;eV to 1&#160;keV. One key point of improvement of IMAP-Lo compared to IBEX-Lo is having more accurate calibration methods for ENAs at hand. The IMAP-Lo calibration will be carried out in MEFISTO, a calibration facility for ion and neutral particle instruments at the University of Bern. MEFISTO consists of an ion beam source with energies 10 eV/q - 100 keV/q, a removeable beam neutralization stage for neutral atoms from 10 eV to 3 keV, and a large vacuum test chamber.The beam neutralization process relies on a charge conversion surface and thus results in an energy loss of about 15%, and energy-dependent transmission. It is therefore essential to be able to measure the effective neutral particle flux and beam energies provided at the exit of the neutraliser to improve the calibration process for an ENA instrument, such as IMAP-Lo.The Absolute Beam Monitor (ABM) is a new laboratory device dedicated to measure the absolute neutral particle flux and coarse energy distribution of a neutral atom beam. The present prototype consists of a tungsten start surface [GJ(1]&#160;and two electron multipliers contained in a box of about 1&#160;dm3 volume. By counting the start, stop and coincidence signal rates we infer the effective number of neutral atoms. In addition, the particle energy is determined by a time-of flight measurement.We present the measurement principle and demonstrate the validity of the concept with the ABM prototype. Neutral H, He, and O beams at different energies and fluxes have been evaluated in MEFISTO with the ABM prototype. The results are compared with IBEX-Lo calibration measurements.

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Determination of Ion Beam Properties In Nitrogen and Helium Using Mather Type Plasma Focus Device

Jurnal Teknologi ◽

10.11113/jt.v71.3852 ◽

2014 ◽

Vol 71 (5) ◽

Author(s):

Someraa Saleh Shakonah ◽

Jalil Ali ◽

Natashah Abd. Rashid ◽

Kashif Chaudhary

Keyword(s):

Plasma Focus ◽

Beam Energy ◽

Ion Beam ◽

Beam Current ◽

Plasma Focus Device ◽

Lee Model Code ◽

Beam Source ◽

Model Code ◽

Pressure Regime

Some of ion beam properties have been investigated by using Lee model code on plasma focus devices which is operated with nitrogen and helium gases. The operation of plasma focus in different pressure regime gives a consistent ion beam properties which can make the plasma focus a reliable ion beam source .These ion beam properties such as ion beam flux, ion beam fluence, ion beam energy, ion beam current, and beam ion number corresponding to gas pressure have been studied for Mather type plasma focus device. The result shows the differences between helium as lighter gas and nitrogen as heavier gas in term of ion beam properties. The fluence and flux are decrease for nitrogen while increase for helium.

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Neutral Beam Source Design and Beam Kinetic Energy Activated SiO2 Etching

MRS Proceedings ◽

10.1557/proc-279-803 ◽

1992 ◽

Vol 279 ◽

Cited By ~ 2

Author(s):

Lee Chen ◽

Akihisa Sekiguchi ◽

Dragan Podlesnik

Keyword(s):

Kinetic Energy ◽

Chemical Reaction ◽

Incident Energy ◽

Beam Energy ◽

Large Diameter ◽

Low Energy ◽

Neutral Beam ◽

Beam Source ◽

Neutral Radical ◽

Unique Method

ABSTRACTAn unique method is used to produce a low energy nonthermalized fast neutral radical beam wliich can activate the SiO2 surface for chemical reaction at the desired incident energy. The fast neutral beam energy is continuously adjustable (2eV<Ek<200eV) and the beam flux is typically 5×1015cm−2 sec−1(∼4L). An uniform large diameter plasma is also made for the production of neutral beam covering 5”wafer and larger. Large diameter neutral beam single wafer reactor is feasible with off-the-shelf pumping technology.

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Design of a Compact Negative Metal Ion Beam Source for Surface Studies

MRS Proceedings ◽

10.1557/proc-396-623 ◽

1995 ◽

Vol 396 ◽

Cited By ~ 6

Author(s):

Y. Park ◽

Y.W. Ko ◽

M.H. Sohn ◽

S.I. Kim

Keyword(s):

Solid State ◽

Metal Ion ◽

Beam Energy ◽

Ion Beam ◽

High Vacuum ◽

Ion Source ◽

Ultra High Vacuum ◽

Negative Ion ◽

Beam Diameter ◽

Beam Source

AbstractA compact negative metal ion beam source for direct low energy metal ion beam depositions studies in ultra high vacuum (UHV) environment, has been developed. The ion source is based on SKION's Solid State Ion Beam Technology. The secondary negative metal ion beam is effectively produced by primary cesium positive ion bombardment (negative ion yield varies from 0.1-0.5 for carbon). The beam diameter is in the range of 0.2∼3.0 cm depending on the focusing and ion beam energy. The ion source produces negative ion currents of about 0.8 mA/cm2. The energy spread of the ion beam is less then ±5% of the ion beam energy. The energy of negative metal ion beam can be independently controlled in the range of 10-300 eV. Due to the complete solid state ion technology , the source can be operated while maintaining chamber pressures of less then 10-10 Torr.

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Formation of High Flux Parallel Neutral Beam Using a Three Grid System of Ion Beam during Low Angle Forward Reflection of Ions

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.124-126.275 ◽

2007 ◽

Vol 124-126 ◽

pp. 275-278 ◽

Cited By ~ 3

Author(s):

Byoung Jae Park ◽

Kyoung Seok Min ◽

Sang Duk Park ◽

Jeong Woon Bae ◽

Oleksiy Vozniy ◽

...

Keyword(s):

Ion Beam ◽

Ion Flux ◽

Neutral Beam ◽

High Flux ◽

Grid System ◽

Beam Source ◽

Ion Energy ◽

Grid Systems ◽

Negative Voltage ◽

Etch Rates

The energy and the flux of the ion gun with a three-grid system was compared with those of the ion gun with a two-grid system and the characteristics of the neutral beam sources composed of the ion guns with different grid systems and a reflector for the low angle reflection of the ions were investigated. By using the three-grid system instead of the two-grid system and by applying higher negative voltage to the 2nd grid, a higher ion flux without changing the ion energy could be obtained for the ion gun of the neutral beam source. The three-grid ion gun system generated higher neutral beam fluxes compared to the two-grid ion gun system. This result was confirmed by measuring the etch rates of Si and GaAs with Ar and fluorine neutral beam. Also, using the neutral beam source with the three-grid ion gun, 35nm-width Si patterns could be etched vertically by CF4 gas indicating the formation of a parallel neutral beam.

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Measurement of ion and neutral beam energy distribution by using a neutral particle analyzer

The 30th International Conference on Plasma Science, 2003. ICOPS 2003. IEEE Conference Record - Abstracts. ◽

10.1109/plasma.2003.1228705 ◽

2003 ◽

Author(s):

D.C. Kim ◽

S.J. Yoo ◽

B.J. Lee ◽

T. Lho ◽

Y.H. Kim ◽

...

Keyword(s):

Energy Distribution ◽

Beam Energy ◽

Neutral Particle ◽

Neutral Beam ◽

Neutral Particle Analyzer

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Influence of argon neutral beam energy on the structural properties of amorphous carbon thin films grown by neutral particle beam assisted sputtering

Thin Solid Films ◽

10.1016/j.tsf.2011.04.063 ◽

2011 ◽

Vol 519 (20) ◽

pp. 6703-6707 ◽

Cited By ~ 4

Author(s):

DongHyeok Lee ◽

JinNyoung Jang ◽

KwangHo Kwon ◽

SukJae You ◽

BonJu Lee ◽

...

Keyword(s):

Thin Films ◽

Structural Properties ◽

Amorphous Carbon ◽

Beam Energy ◽

Neutral Particle ◽

Particle Beam ◽

Neutral Beam ◽

Carbon Thin Films

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The R&D Activities and Future Plan of 4MW Hot Cathode Ion Source for EAST Neutral Beam Injector

Volume 5: Advanced and Next Generation Reactors, Fusion Technology; Codes, Standards, Conformity Assessment, Licensing, and Regulatory Issues ◽

10.1115/icone25-66218 ◽

2017 ◽

Author(s):

Yahong Xie ◽

Chundong Hu ◽

Sheng Liu ◽

Jun Li ◽

Yuanlai Xie ◽

...

Keyword(s):

High Power ◽

Beam Energy ◽

Ion Beam ◽

Ion Source ◽

Neutral Beam ◽

Beam Power ◽

Test Bed ◽

Steady State Operation ◽

Long Pulse ◽

Positive Ion

The Experimental Advanced Superconducting Tokamak (EAST) is one of the fully superconducting tokamak, its aim at the long-pulse operation (1000s) to study the physics of steady-state operation for nuclear fusion sciences. In order to support the steady-state operation and physical research, the high power neutral beam injection (NBI) system need to be employed on the EAST for the plasma heating and current driving. According to the scientific study schedule of the EAST, the designed NBI system includes two beam lines which will be constructed in two phases. Each beam line will deliver a deuterium neutral beam with beam energy of 50–80 keV with beam duration of 10–100 s. Each beam line has the maximum beam power of 4MW. The high current ion source is one of the most important parts in the high power NBI. A hot cathode positive ion based source was developed for EAST-NBI, which shown in Fig. 1. The ion source contains a bucket hot cathode arc chamber with 650 mm long, 260 mm width and 300 mm depth. There are 32 hairpin filaments with diamond of 1.5 mm and 160 mm long to supply primary electrons. A tetrode type accelerator with slit type used to extract the ions from the plasma and accelerated to the desired energy. The beam extraction area is 120 mm × 480 mm (can be changed) with beam transmittance of 60 %. The designed beam species is deuterium with beam power of 2–4 MW and beam energy of 50–80 keV and beam pulse length of 10–100 s. The ion source needs to be conditioning before operation on the EAST-NBI. An ion source test bed was designed and developed for the ion source performance tests and the optimization verification. The characteristics of ion source were tested with hydrogen beam, and each ion source should achieve 4MW ion beam with beam energy of 80 keV. The optimum beam perveance and arc efficiency were analyzed too. The optimum beam perveance was 2.8 μp with beam energy of 50 keV and the arc efficiency was 0.55A/kw. Long pulse operation was one of the requests of EAST ion source. The real-time feedback control method was employed and can got stable plasma and ion beam. The beam extraction was tested to achieve 100 s on the test bed. Consider the high power deposited on the calorimeter, the beam was modulated with suitable frequency and duty ratio. When the conditioning finished, the ion sources were moved to the EAST-NBI. The deuterium beam was extracted and injected into the EAST plasma. Details of the performance of positive ion source on the test bed and EAST-NBI will be presented.

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