Quadrupole mass filter operation under the influence of magnetic field

Syed, Sarfaraz U. A. H.; Maher, Simon; Taylor, Stephen

doi:10.1002/jms.3293

Cited by 12 publications

(7 citation statements)

References 30 publications

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“…In their original work much emphasis was placed on the fact that the QMS separates ions without the use of magnetic fields. Recent investigations have shown that applying a magnetic field to the body of the QMS electrode assembly can enhance device performance (Maher et al, 2013;Syed, Maher, and Taylor, 2013). At that time they filed patents in several countries for the QMS (Paul and Steinwedel, 1956) and the quadrupole ion trap (QIT), which utilizes a three-dimensional field to trap ions.…”

Section: Single Focusing Magnetic Sectormentioning

confidence: 99%

Colloquium: 100 years of mass spectrometry: Perspectives and future trends

2015

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Mass spectrometry (MS) is widely regarded as the most sensitive and specific general purpose analytical technique. More than a century has passed for MS since the groundbreaking work of Nobel laureate Sir Joseph John Thomson in 1913. This Colloquium aims to (1) give an historical overview of the major instrumentation achievements that have driven mass spectrometry forward in the past century, including those leading up to the initial work of Thomson, (2) provide the nonspecialist with an introduction to MS, and (3) highlight some key applications of MS and explore the current and future trends. Because of the vastness of the subject area and quality of the manifold research efforts that have been undertaken over the last 100 years, which have contributed to the foundations and subsequent advances in mass spectrometry, it should be understood that not all of the key contributions may have been included in this Colloquium. Mass spectrometry has embraced a multitude of scientific disciplines and to recognize all of the achievements is an impossible task, such has been the diverse impact of this invaluable technique. Scientific progress is usually made via the cumulative effort of a large number of researchers; the achievements reported herein are only a representation of that effort.

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Section: Single Focusing Magnetic Sectormentioning

confidence: 99%

Colloquium: 100 years of mass spectrometry: Perspectives and future trends

2015

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“…The results presented in this article are of interest beyond the solenoid-electron beam configuration studied. Our calculations demonstrate the feasibility of using such an approach for modelling charged particle optics in general [15][16][17][18][19].…”

Section: Discussionmentioning

confidence: 67%

Evaluation of Electron Beam Deflections Across a Solenoid Using Weber-Ritz and Maxwell-Lorentz Electrodynamics

Smith¹,

Jjunju²,

Maher³

2015

PIER

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Abstract-The deflection of charged particle beams by electric and/or magnetic fields is invariably based on the field centred approach associated with Maxwell-Lorentz and incorporated into the Lorentz force formula. Here we present an alternative method of calculation based on the force formula of Weber-Ritz and which does not involve, directly, the field entities E and B. In this study we evaluate the deflection of an electron beam by a long solenoid carrying direct current and positioned centrally across the beam. The experiment has some bearing on the Aharonov-Bohm effect in that our calculations indicate that even for very long solenoids the classical force on the beam remains finite. The standard interpretation of the effect is, however, in terms of quantum mechanics and vector potential. Experimental measurements have been made of electron beam deflections by three solenoids, 0.25 m, 0.50 m and 0.75 m long; each solenoid is doubly wound with the same winding density (2600 turns per metre) and carrying the same current of 5.00 A d.c.. Our results indicate that, within the limits of experimental error, both Weber-Ritz and Maxwell-Lorentz theories correlate with measurements for the longer solenoids. However in the case of the shortest solenoid, the lack of uniformity of the magnetic field, leads to significant error in the calculation of beam deflection by the Lorentz force. By contrast in a Weber-Ritz calculation a precise value of beam deflection is obtained by equating the impulse of the non uniform beam force to the vertical momentum change of the electron. This is a fundamentally different approach which uses a statistical summation of forces on the beam in terms of relative velocities between moving electrons and involves a direct computation of the vertical force on the beam due to the circling solenoid current. This method has distinct advantages in terms of economy; that is, it does not involve directly field entities E and B, nor the leakage flux from the solenoid or the vector potential.

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“…Furthermore, this method may have implications for studying the influence of near-field EM interactions with biological bodies. Because the Weber force formulation describes moving charges and these do not necessarily have to be electrons in a copper wire, the theory might well be extended to charged particles in motion [47][48][49][50][51] or ionic species in biomedical systems [52][53][54], in particular providing insights into the effects of EM induction on specific biological processes.…”

Section: Discussionmentioning

confidence: 99%

A physical model for low-frequency electromagnetic induction in the near field based on direct interaction between transmitter and receiver electrons

et al. 2016

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A physical model of electromagnetic induction is developed which relates directly the forces between electrons in the transmitter and receiver windings of concentric coaxial finite coils in the near-field region. By applying the principle of superposition, the contributions from accelerating electrons in successive current loops are summed, allowing the peak-induced voltage in the receiver to be accurately predicted. Results show good agreement between theory and experiment for various receivers of different radii up to five times that of the transmitter. The limitations of the linear theory of electromagnetic induction are discussed in terms of the non-uniform current distribution caused by the skin effect. In particular, the explanation in terms of electromagnetic energy and Poynting’s theorem is contrasted with a more direct explanation based on variable filament induction across the conductor cross section. As the direct physical model developed herein deals only with forces between discrete current elements, it can be readily adapted to suit different coil geometries and is widely applicable in various fields of research such as near-field communications, antenna design, wireless power transfer, sensor applications and beyond.

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Quadrupole mass filter operation under the influence of magnetic field

Cited by 12 publications

References 30 publications

Colloquium: 100 years of mass spectrometry: Perspectives and future trends

Colloquium: 100 years of mass spectrometry: Perspectives and future trends

Evaluation of Electron Beam Deflections Across a Solenoid Using Weber-Ritz and Maxwell-Lorentz Electrodynamics

A physical model for low-frequency electromagnetic induction in the near field based on direct interaction between transmitter and receiver electrons

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