نتایج جستجو برای: ion laser

تعداد نتایج: 382100  

2016
A. Stockem Novo M. C. Kaluza R. A. Fonseca L. O. Silva

We demonstrate how to tune the main ion acceleration mechanism in laser-plasma interactions to collisionless shock acceleration, thus achieving control over the final ion beam properties (e. g. maximum energy, divergence, number of accelerated ions). We investigate this technique with three-dimensional particle-in-cell simulations and illustrate a possible experimental realisation. The setup co...

Journal: :Physical review letters 2012
F Fiuza A Stockem E Boella R A Fonseca L O Silva D Haberberger S Tochitsky C Gong W B Mori C Joshi

We show that monoenergetic ion beams can be accelerated by moderate Mach number collisionless, electrostatic shocks propagating in a long scale-length exponentially decaying plasma profile. Strong plasma heating and density steepening produced by an intense laser pulse near the critical density can launch such shocks that propagate in the extended plasma at high velocities. The generation of a ...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2015
R Capdessus P McKenna

The role of the radiation reaction force in ultraintense laser-driven ion acceleration is investigated. For laser intensities ∼10(23)W/cm(2), the action of this force on electrons is demonstrated in relativistic particle-in-cell simulations to significantly enhance the energy transfer to ions in relativistically transparent targets, but strongly reduce the ion energy in dense plasma targets. An...

2007
Philip J. Richerme Isaac L. Chuang David E. Pritchard

This thesis describes the design and construction of two laser systems to probe the 674nm transition of 88Sr+ ions in a linear Paul trap. The first laser system made use of a molecular transition in Iodine to stabilize the length of a Fabry-Perot cavity for laser locking. After constructing this laser, we measured an unsuitable experimental stability of 10 MHz over 5 minutes. A completely new m...

2009
M. Grech S. Skupin E. Lefebvre

We present a novel laser-based ion acceleration scheme, where a petawatt circularly polarized laser pulse is shot on an ultra-thin (nano-scale) double-layer target. Our scheme allows the production of high-quality light ion beams with both energy and angular dispersion controllable by the target properties. We show that extraction of all electrons from the target by radiation pressure can lead ...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2015
W Bang B J Albright P A Bradley E L Vold J C Boettger J C Fernández

In a recent experiment at the Trident laser facility, a laser-driven beam of quasimonoenergetic aluminum ions was used to heat solid gold and diamond foils isochorically to 5.5 and 1.7 eV, respectively. Here theoretical calculations are presented that suggest the gold and diamond were heated uniformly by these laser-driven ion beams. According to calculations and SESAME equation-of-state tables...

2003
U Schramm T Schätz M Bussmann

The crystallization of ion beams has recently been established in the rf quadrupole storage ring PALLAS (PAul Laser CooLing Acceleration System) for laser-cooled 24Mg+ ion beams at an energy of about 1 eV. Yet, unexpectedly sharp constraints had to be met concerning the confinement strength and the longitudinal laser cooling rate. In this paper, related and up to now unseen heating mechanisms a...

2005
Christian Tamm

A fundamental limit to the stability of a single-ion optical frequency standard is set by quantum noise in the measurement of the internal state of the ion. We discuss how the interrogation sequence and the processing of the atomic resonance signal can be optimized in order to obtain the highest possible stability under realistic experimental conditions. A servo algorithm is presented that stab...

Journal: :Analytical chemistry 2012
Jiahui Peng Noah Puskas Paul B Corkum David M Rayner Alexandre V Loboda

We describe a novel ion source for analytical mass spectrometry based on femtosecond laser ionization at pressures at and above atmospheric and characterize its performance when coupled to a tandem quadrupole/time-of-flight mass spectrometer. We assess source saturation limits, ionization and sampling efficiencies, the effective ionization volume, and limits of detection. We demonstrate 100% ef...

پایان نامه :دانشگاه آزاد اسلامی واحد علوم پزشکی تهران - دانشکده پزشکی 1390

هدف: این مطالعه به منظور بررسی و مقایسه اثر q-switched nd yag laser و erbium laser در درمان ضایعات پیگمانته انجام شده است. روش مطالعه: 116 فرد مبتلا به ضایعات پیگمانته از نوع فرکل و خال وارد مطالعه شدند که 58 مورد با استفاده از q-switched nd yag laser و 58 مورد با لیزر erbium درمان شدند و در نهایت میزان اثربخشی (از بین رفتن کامل ضایعات) در دو گروه تعیین و مقایسه گردید. یافته ها: در این مطالعه...

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