A novel ion beam monitor using Kapton foils

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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Beam monitor calibration of a synchrotron-based scanned light-ion beam delivery system

Zeitschrift für Medizinische Physik ◽

10.1016/j.zemedi.2020.06.005 ◽

2020 ◽

Author(s):

Jhonnatan Osorio ◽

Ralf Dreindl ◽

Loïc Grevillot ◽

Virgile Letellier ◽

Peter Kuess ◽

...

Keyword(s):

Delivery System ◽

Ion Beam ◽

Beam Monitor ◽

Beam Delivery ◽

Beam Delivery System

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Development of new ion beam monitor system using conductive mesh

2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC) ◽

10.1109/nssmic.2013.6829491 ◽

2013 ◽

Keyword(s):

Ion Beam ◽

Monitor System ◽

Beam Monitor

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Direct Observations of the Epitaxial Growth of Sputtered Ag on Si

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071053 ◽

1973 ◽

Vol 31 ◽

pp. 122-123

Author(s):

J. S. Maa ◽

Thos. E. Hutchinson

Keyword(s):

Epitaxial Growth ◽

Film Growth ◽

Ion Beam ◽

Ion Beam Sputtering ◽

Microscopy Technique ◽

Direct Observations ◽

In Situ Electron Microscopy ◽

Beam Sputtering ◽

The Subject

The growth of Ag films deposited on various substrate materials such as MoS2, mica, graphite, and MgO has been investigated extensively using the in situ electron microscopy technique. The three stages of film growth, namely, the nucleation, growth of islands followed by liquid-like coalescence have been observed in both the vacuum vapor deposited and ion beam sputtered thin films. The mechanisms of nucleation and growth of silver films formed by ion beam sputtering on the (111) plane of silicon comprise the subject of this paper. A novel mode of epitaxial growth is observed to that seen previously.The experimental arrangement for the present study is the same as previous experiments, and the preparation procedure for obtaining thin silicon substrate is presented in a separate paper.

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Effects of Ion Beam Milling on Surface Topography

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070862 ◽

1973 ◽

Vol 31 ◽

pp. 84-85

Author(s):

P.G. Pawar ◽

P. Duhamel ◽

G.W. Monk

Keyword(s):

Surface Topography ◽

Ion Beam ◽

Solid Material ◽

Beam Current ◽

Atomic Mass ◽

Micro Milling ◽

Ion Milling ◽

Controlled Atmospheres ◽

Milling Operations ◽

Sufficient Energy

A beam of ions of mass greater than a few atomic mass units and with sufficient energy can remove atoms from the surface of a solid material at a useful rate. A system used to achieve this purpose under controlled atmospheres is called an ion miliing machine. An ion milling apparatus presently available as IMMI-III with a IMMIAC was used in this investigation. Unless otherwise stated, all the micro milling operations were done with Ar+ at 6kv using a beam current of 100 μA for each of the two guns, with a specimen tilt of 15° from the horizontal plane.It is fairly well established that ion bombardment of the surface of homogeneous materials can produce surface topography which resembles geological erosional features.

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