Communication: Time- and space-sliced velocity map electron imaging

Lee, Suk Kyoung; Lin, Yun Fei; Lingenfelter, Steven; Fan, Lin; Winney, Alexander H.; Li, Wen

doi:10.1063/1.4903744

Cited by 39 publications

(28 citation statements)

References 23 publications

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“…52 for discussion of multi-hit delay-line anodes for VMI, the works of Li and co-workers for the use of fast frame cameras in conjunction with a high-speed digitizers, [53][54][55] and Vallance et al for general discussion of fast sensors for VMI. 25 In terms of probing ultrafast molecular dynamics in polyatomic molecules, the capabilities and benefits of multi-mass ion imaging are clear.…”

Section: Discussionmentioning

confidence: 99%

Time-resolved multi-mass ion imaging: Femtosecond UV-VUV pump-probe spectroscopy with the PImMS camera

Forbes

Makhija

Veyrinas

et al. 2017

The Journal of Chemical Physics

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The Pixel-Imaging Mass Spectrometry (PImMS) camera allows for 3D charged particle imaging measurements, in which the particle time-of-flight is recorded along with (x, y) position. Coupling the PImMS camera to an ultrafast pump-probe velocity-map imaging spectroscopy apparatus therefore provides a route to time-resolved multi-mass ion imaging, with both high count rates and large dynamic range, thus allowing for rapid measurements of complex photofragmentation dynamics. Furthermore, the use of vacuum ultraviolet wavelengths for the probe pulse allows for an enhanced observation window for the study of excited state molecular dynamics in small polyatomic molecules having relatively high ionization potentials. Herein, preliminary time-resolved multi-mass imaging results from CFI photolysis are presented. The experiments utilized femtosecond VUV and UV (160.8 nm and 267 nm) pump and probe laser pulses in order to demonstrate and explore this new time-resolved experimental ion imaging configuration. The data indicate the depth and power of this measurement modality, with a range of photofragments readily observed, and many indications of complex underlying wavepacket dynamics on the excited state(s) prepared.

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Section: Discussionmentioning

confidence: 99%

Time-resolved multi-mass ion imaging: Femtosecond UV-VUV pump-probe spectroscopy with the PImMS camera

Forbes

Makhija

Veyrinas

et al. 2017

The Journal of Chemical Physics

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“…It features a 3D imaging system with a zero deadtime detection of electron-electron coincidence. This limit has now been removed with the development of a new type of 3D imaging system, which features a camera and a waveform digitizer 24,25 . The physical dead-time is well under one nanosecond and a zero dead-time detection has also been achieved 26 .…”

Section: Figure 1 (A)mentioning

confidence: 99%

Attosecond Electron Correlation Dynamics in Double Ionization of Benzene Probed with Two-Electron Angular Streaking

et al. 2017

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With a novel three-dimensional electron-electron coincidence imaging technique and two-electron angular streaking method, we show that the emission time delay between two electrons can be measured from tens of attoseconds to more than 1 fs. Surprisingly, in benzene, the double ionization rate decays as the time delay between the first and second electron emission increases during the first 500 as. This is further supported by the decay of the Coulomb repulsion in the direction perpendicular to the laser polarization. This result reveals that laser-induced electron correlation plays a major role in strong field double ionization of benzene driven by a nearly circularly polarized field.

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“…Time-sliced or DC sliced velocity map imaging is a widely used experimental method that has a number of favorable attributes compared with the standard ion-imaging and velocity map imaging techniques. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Its main advantage is the significant improvement in the signal to noise ratio of the recorded images. This leads to greater quality of the resulting spectra and a reduction in the data acquisition time.…”

Section: Introductionmentioning

confidence: 99%

Finite slice analysis (FINA) of sliced and velocity mapped images on a Cartesian grid

Thompson

Amarasinghe

Foley

et al. 2017

The Journal of Chemical Physics

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Although time-sliced imaging yields improved signal-to-noise and resolution compared with unsliced velocity mapped ion images, for finite slice widths as encountered in real experiments there is a loss of resolution and recovered intensities for the slow fragments. Recently, we reported a new approach that permits correction of these effects for an arbitrarily sliced distribution of a 3D charged particle cloud. This finite slice analysis (FinA) method utilizes basis functions that model the out-of-plane contribution of a given velocity component to the image for sequential subtraction in a spherical polar coordinate system. However, the original approach suffers from a slow processing time due to the weighting procedure needed to accurately model the out-of-plane projection of an anisotropic angular distribution. To overcome this issue we present a variant of the method in which the FinA approach is performed in a cylindrical coordinate system (Cartesian in the image plane) rather than a spherical polar coordinate system. Dubbed C-FinA, we show how this method is applied in much the same manner. We compare this variant to the polar FinA method and find that the processing time (of a 510 × 510 pixel image) in its most extreme case improves by a factor of 100. We also show that although the resulting velocity resolution is not quite as high as the polar version, this new approach shows superior resolution for fine structure in the differential cross sections. We demonstrate the method on a range of experimental and synthetic data at different effective slice widths.

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Communication: Time- and space-sliced velocity map electron imaging

Cited by 39 publications

References 23 publications

Time-resolved multi-mass ion imaging: Femtosecond UV-VUV pump-probe spectroscopy with the PImMS camera

Time-resolved multi-mass ion imaging: Femtosecond UV-VUV pump-probe spectroscopy with the PImMS camera

Attosecond Electron Correlation Dynamics in Double Ionization of Benzene Probed with Two-Electron Angular Streaking

Finite slice analysis (FINA) of sliced and velocity mapped images on a Cartesian grid

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