100 years of ion beams: Willy Wien's canal rays

Wien, K.

doi:10.1590/s0103-97331999000300002

Cited by 19 publications

(8 citation statements)

References 1 publication

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“…Earliest tests for verification of Doppler effect for spontaneous photon emission from moving emitters were conducted with so called 'canal rays' or positive ion beams (Wien, 1999). However, based on an invalid assumption of fast moving ions emitting photons in gas discharge tubes, Stark, (1907) had claimed the verification of Doppler effect by measuring some Doppler shifts in Hydrogen spectrum lines.…”

Section: Tests For Verification Of Doppler Effect For Photonsmentioning

confidence: 99%

Distinct Doppler Effects for Spontaneously Emitted Photons and Continuously Emitted Waves

Sandhu¹

2017

APR

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In this paper, we distinguish between the Doppler effects for spontaneously emitted photons and continuously emitted waves. Under certain plausible assumptions, electron orbits can be modeled for simple atomic systems and such studies show that all permissible electron trajectories correspond to elliptical orbits. From the conservation of energy, momentum and angular momentum, in conjunction with the geometrical model of electron orbits, we derive the Doppler effect for spontaneously emitted photons that is quite different from the one used for continuously generated waves. All astronomical redshifts are currently interpreted by assuming the incoming radiation to be continuously emitted waves. Therefore, widely-observed redshift in radiation from most astronomical sources is interpreted to imply the expanding universe, along with cosmological expansion of space. However, for the spontaneously emitted photons, we show that the photons emitted in forward direction parallel to the emitter velocity get redshifted. That means, the astronomical redshift implies that the emission sources are moving towards the observer and our universe is not expanding. All high redshift astronomical objects are likely to be physically disrupted through dynamic instabilities or explosions and their high redshifts are associated with relativistic shock waves propagating towards the observer. Hence the proposed Doppler effect for the spontaneously emitted photons dismisses the cosmological expansion of space and supports a steady state universe.

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Section: Tests For Verification Of Doppler Effect For Photonsmentioning

confidence: 99%

Distinct Doppler Effects for Spontaneously Emitted Photons and Continuously Emitted Waves

Sandhu¹

2017

APR

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“…In order to separate particles of different masses, we will use the perpendicular electric and magnetic fields of a Wien filter [15,16]. Since we have chosen to have horizontal bends, it is better to separate the beams vertically, i. e. in the plane with minimum dispersion.…”

Section: Separatormentioning

confidence: 99%

MuSR Beam Line Design Studies

MacKay¹,

Fischer

Pile

et al. 2013

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When a substance is implanted with positive muons the precession of their magnetic moments can be used to sample the magnetic properties of the material. The information obtained is complementary to that from NMR, ESR, and neutron scattering. To date, only four user facilities exist in the world but none in the US. We explore the possibility of using the AGS complex at BNL for a µSR facility for the production of positive surface muons. With an incident proton intensity of 10 14 protons per second hitting a 200 mm long 0.5 mm thick graphite target, our preliminary design of the beam line could produce low momentum surface muons (24-30 MeV/c) with a flux of 0.9 MHz/cm 2 for experiments.

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“…13, The Wien filter was invented by Wilhelm Wien more than a hundred years ago, 67 but it is not so often used as an electron energy filter, probably due to the fringe effect. In a Wien filter, the magnetic and electric fields are applied perpendicularly to each other.…”

Section: Wien Filter Energy Analyzer For Expeemmentioning

confidence: 99%

Energy Filtered X-Ray Photoemission Electron Microscopy

Asakura

Niimi

Katô

2010

Advances in Imaging and Electron Physics

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2 Photoemission electron microscopy (PEEM) and energy filtered X-ray PEEM (EXPEEM) are reviewed. PEEM enables the in situ observation of surface chemical phenomena resolved in space and time. In order to achieve surface chemical imaging, excitation at the core level is preferable and a combination of PEEM and X-ray photoelectron spectroscopy is necessary which has been realized by the EXPEEM. We review in particular an EXPEEM installed with a Wien filter energy analyzer are reviewed. Examples of the practical application of PEEM and EXPEEM to surface chemistry are presented. AbstractThis chapter reviews photoemission electron microscopy(PEEM) and energy filtered X-ray PEEM (EXPEEM) that provides us the chemical mapping of the surface. We describe the history and the principle of PEEM and EXPEEM. We focus on the Wien filter type energy The surface is illuminated by a UV lamp and photoelectrons are ejected from the surface, depending on the local work function. The work function of O 2 is larger than CO and the amount of electrons coming from the O 2 -adsorbed surface becomes smaller; therefore, the dark and bright regions correspond to the O 2 and CO adsorbed domains, respectively. PEEM had revealed that surface reactions are inhomogenous, even on a single crystal and in situ surface microscopy is necessary since the pattern is formed under reaction conditions.The PEEM image in Fig. 1 shows the distribution of O 2 and CO that can be obtained only by their different work functions when they are adsorbed on a surface. Therefore, PEEM can not 3 be applied to complex systems where the work functions of the reaction components are not so easily distinguished. However, PEEM has the following advantages: 1) less specimen damage than conventional electron microscopy, and 2) versatility to provide physical and chemical information by the selection of excitation photon sources. 2,3In contrast to transmission electron microscopy (TEM) or scanning electron microscopy (SEM), PEEM requires a photon source that has a small interaction with matter, resulting in minimal sample damage. The second advantage is related to the photoemission mechanism of PEEM. Although the amount of photoelectrons excited by a simple UV light source is simply related to the work function of the surface, 3 the number of excited photoelectrons depends on the local magnetism of the surface when circularly or linearly polarized light is used. 4,5 X-rays excite the core electrons, which contain chemical information. Synchrotron radiation 6 is an energy-tunable X-ray source, which can be used to obtain chemically-sensitive PEEM images when the X-ray energy is set near the absorption edge energy. On the other hand, kinetic energy analysis of the photoelectrons is necessary to obtain chemically sensitive PEEM images for a constant photon energy source such as conventional Bremsstrahlung X-rays. PEEM combined with photoelectron energy analysis is referred to as an energy filtered X-ray PEEM (EXPEEM). 7-13One challenging aspect is the weak photoelectron peak si...

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100 years of ion beams: Willy Wien's canal rays

Cited by 19 publications

References 1 publication

Distinct Doppler Effects for Spontaneously Emitted Photons and Continuously Emitted Waves

Distinct Doppler Effects for Spontaneously Emitted Photons and Continuously Emitted Waves

MuSR Beam Line Design Studies

Energy Filtered X-Ray Photoemission Electron Microscopy

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