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New sources and applications of super-radiance
Published in M. G. Benedict, A. M. Ermolaev, V. A. Malyshev, I. V. Sokolov, E. D. Trifonov, Super-radiance, 2018
M. G. Benedict, A. M. Ermolaev, V. A. Malyshev, I. V. Sokolov, E. D. Trifonov
The principle of the DeVoe-Brewer experiment is to measure the spontaneous emission rate of the two-ion crystal formed in an RF Paul trap, as a function of the ion-ion separation, r. The measured rates were compared with the corresponding rates for a single trapped ion. The set-up of the experiment is shown in figure 11.6 where two 138Ba+ ions forming a stable ‘crystallic’ system are cooled by using two frequency-stabilized carrier-wave (cw) dye lasers. The ionic crystal was viewed, through a sapphire window, by a microscope objective with a compensation for the spherical aberration of the window. A typical diffraction-limited image of the crystal recorded in the experiment is shown in figure 11.7.
Proteins and Proteomics
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2020
Top-down proteomics is a method of protein identification that uses an ion-trapping mass spectrometer to store an isolated protein ion for mass measurement and tandem mass spectrometry analysis. The name is derived from the similar approach to DNA sequencing. Proteins are typically ionized by ESI and trapped in a Fourier transform ion cyclotron resonance (Penning trap) or quadruple ion trap (Paul trap) mass spectrometer. Fragmentation for tandem mass spectrometry is accomplished by electron capture dissociation or electron transfer dissociation.
Proteins and proteomics
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2018
Top-down proteomics is a method of protein identification that uses an ion-trapping mass spectrometer to store an isolated protein ion for mass measurement and tandem mass spectrometry analysis. The name is derived from the similar approach to DNA sequencing. Proteins are typically ionized by ESI and trapped in a Fourier transform ion cyclotron resonance (Penning trap) or quadruple ion trap (Paul trap) mass spectrometer. Fragmentation for tandem mass spectrometry is accomplished by electron capture dissociation or electron transfer dissociation.
Low-vacuum cylindrical ion trap mass spectrometry
Published in Instrumentation Science & Technology, 2018
Peihe Jiang, Zhiquan Zhou, Zhongjie Wu, Zhanfeng Zhao
In a Paul trap, the oscillation motion of an ion is driven by the quadrupolar field. Letting u represent the r- or z-direction, if the velocity of an ion in direction u is vu, according to Stokes’ law, the damping force of an ion in the u direction iswhere ŋ is the viscosity associated with not only the pressure of the background gas but also the size and shape of the ion and R is the radius of the ion. In the u direction, the equation of motion is then given bywhere U and V are the DC and AC potential components applied to the ring electrode, respectively, Ω is the angular frequency of the AC field (in rad/s), t is the time, and r0 and z0 are the size of the ion trap.
Single-ion, transportable optical atomic clocks
Published in Journal of Modern Optics, 2018
Marion Delehaye, Clément Lacroûte
All single-ion atomic clocks rely on a variation on the Paul trap [99], which uses a combination of DC and RF electric fields to stably trap the ion. As a potential minimum cannot be generated at a point in space with static electric fields alone, the idea of the Paul trap is to combine static and radio-frequency electric fields with amplitudes and frequency such that, depending on the ion mass, the average electric potential seen by the ion is harmonic. There are several ways to implement such a trap, and we will focus only on the geometries relevant to this article.