Control of the Longitudinal Compression and Transverse Focus of Ultrafast Electron Beam for Detecting the Transient Evolution of Materials

Ultrafast detection is an effective method to reveal the transient evolution mechanism of materials. Compared with ultra-fast X-ray diffraction (XRD), the ultra-fast electron beam is increasingly adopted because the larger scattering cross-section is less harmful to the sample. The keV single-shot ultra-fast electron imaging system has been widely used with its compact structure and easy integration. To achieve both the single pulse imaging and the ultra-high temporal resolution, magnetic lenses are typically used for transverse focus to increase signal strength, while radio frequency (RF) cavities are generally utilized for longitudinal compression to improve temporal resolution. However, the detection signal is relatively weak due to the Coulomb force between electrons. Moreover, the effect of RF compression on the transverse focus is usually ignored. We established a particle tracking model to simulate the electron pulse propagation based on the 1-D fluid equation and the 2-D mean-field equation. Under considering the relativity effect and Coulomb force, the impact of RF compression on the transverse focus was studied by solving the fifth-order Rung–Kutta equation. The results show that the RF cavity is not only a key component of longitudinal compression but also affects the transverse focusing. While the effect of transverse focus on longitudinal duration is negligible. By adjusting the position and compression strength of the RF cavity, the beam spot radius can be reduced from 100 μm to 30 μm under the simulation conditions in this paper. When the number of single pulse electrons remains constant, the electrons density incident on the sample could be increased from 3.18×1012 m−2 to 3.54×1013 m−2, which is 11 times the original. The larger the electron density incident on the sample, the greater the signal intensity, which is more conducive to detecting the transient evolution of the material.

Download Full-text

Single Pulse Emittance Measurement Technique for Intense Relativistic Electron Beam

10.21236/ada457945 ◽

1997 ◽

Author(s):

J. A. Gregor ◽

R. M. Meger ◽

J. A. Antoniades

Keyword(s):

Electron Beam ◽

Relativistic Electron ◽

Measurement Technique ◽

Relativistic Electron Beam ◽

Single Pulse ◽

Emittance Measurement

Download Full-text

1S-A1-2Innovate Electron Beam by GaN Semiconductor Photocathodes Conducive to Single Shot Imaging

Microscopy ◽

10.1093/jmicro/dfx041 ◽

2017 ◽

Vol 66 (suppl_1) ◽

pp. i6-i6

Author(s):

Tomohiro Nishitani ◽

Akihiro Narita ◽

Takeshi Tomita ◽

Shin-ichi Kitamura ◽

Takashi Meguro ◽

...

Keyword(s):

Electron Beam ◽

Single Shot

Download Full-text

Investigation of plasma parameters created by a fast electron beam in a magnetic field

Vacuum ◽

10.1016/0042-207x(71)90093-5 ◽

1971 ◽

Vol 21 (8) ◽

pp. 355

Keyword(s):

Magnetic Field ◽

Electron Beam ◽

Fast Electron ◽

Plasma Parameters ◽

Fast Electron Beam

Download Full-text

LITHOS: A fast electron beam lithography simulator

Microelectronic Engineering ◽

10.1016/0167-9317(94)00165-0 ◽

1995 ◽

Vol 26 (3-4) ◽

pp. 131-140 ◽

Cited By ~ 4

Author(s):

N. Glezos ◽

I. Raptis ◽

M. Hatzakis

Keyword(s):

Electron Beam ◽

Fast Electron ◽

Electron Beam Lithography ◽

Fast Electron Beam

Download Full-text

Space-charge controlled fast electron beam pulsing

Journal of Applied Physics ◽

10.1063/1.1286331 ◽

2001 ◽

Vol 89 (1) ◽

pp. 654-661

Author(s):

Chong-Yu Ruan ◽

Manfred Fink

Keyword(s):

Electron Beam ◽

Space Charge ◽

Fast Electron ◽

Fast Electron Beam ◽

Beam Pulsing

Download Full-text

Temporal structure of the fast electron beam generated in the pseudospark discharge with external triggering

IEEE Transactions on Plasma Science ◽

10.1109/tps.2005.856533 ◽

2005 ◽

Vol 33 (5) ◽

pp. 1648-1653 ◽

Cited By ~ 11

Author(s):

Y.D. Korolev ◽

O.B. Frants ◽

V.G. Geyman ◽

N.V. Landl ◽

R.V. Ivashov ◽

...

Keyword(s):

Electron Beam ◽

Fast Electron ◽

Temporal Structure ◽

Pseudospark Discharge ◽

Fast Electron Beam

Download Full-text

On the investigation of fast electron beam filamentation in laser-irradiated solid targets using multi-MeV proton emission

Plasma Physics and Controlled Fusion ◽

10.1088/0741-3335/53/12/124012 ◽

2011 ◽

Vol 53 (12) ◽

pp. 124012 ◽

Cited By ~ 6

Author(s):

M N Quinn ◽

D C Carroll ◽

X H Yuan ◽

M Borghesi ◽

R J Clarke ◽

...

Keyword(s):

Electron Beam ◽

Fast Electron ◽

Proton Emission ◽

Fast Electron Beam

Download Full-text

Femtosecond Pulsed Laser-Induced Micromachining of Difficult-to-Machine Materials: Diamond a Case Study

10.1115/imece2000-1905 ◽

2000 ◽

Author(s):

A. P. Malshe ◽

A. M. Ozkan ◽

T. A. Railkar ◽

K. P. Adhi ◽

W. D. Brown ◽

...

Keyword(s):

Raman Spectroscopy ◽

Excimer Laser ◽

Etching Rate ◽

Polycrystalline Diamond ◽

Single Pulse ◽

Laser Wavelength ◽

Diamond Surface ◽

Single Shot ◽

Micro Machining ◽

3 Dimensional

Abstract Meso and micro scale machining is an important and emerging area of research. Various non-traditional and novel tools are being explored for meso and micro machining of non-silicon materials. In this paper, we report etching, micro machining and related phenomena of commercially available single and polycrystalline diamond using a femtosecond pulsed excimer laser (λ = 248 nm, tp ∼ 380 fs). Surface modifications due to single pulse and multiple pulse irradiation of diamond samples, at different energy densities, have been analyzed using Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Etching rate of single crystal type IIA diamond by femtosecond pulsed excimer laser is also studied. Raman spectroscopy study of the single shot irradiation of diamond with a femto second laser shows the formation of a non-diamond disordered (sp2 bonded) phase on the surface. However, subsequent micro machining of this non-diamond disordered surface, by delivering several shots from the femtosecond laser, results in the removal of the non-diamond disordered layer and the restoration of the diamond surface. It is experimentally shown that the periodicity of the 2-dimensional corrugations written on diamond surface is shorter than the laser wavelength used. 3-dimensional writing on diamond globules during laser etching is also discussed. Further, micro machining of diamond tips is shown to be precise, and without mechanical and chemical damages. Femto second laser is demonstrated as a next-generation tool for mechanical and chemical damage free precision micro machining of the hardest material, diamond.

Download Full-text

Technical note on measuring run-off dynamics from pavements using a new device: the weighable tipping bucket

Hydrology and Earth System Sciences ◽

10.5194/hess-15-1379-2011 ◽

2011 ◽

Vol 15 (5) ◽

pp. 1379-1386 ◽

Cited By ~ 9

Author(s):

T. Nehls ◽

Y. Nam Rim ◽

G. Wessolek

Keyword(s):

High Resolution ◽

Data Processing ◽

Temporal Resolution ◽

Hydrological Process ◽

Flow Measurements ◽

New Device ◽

Run Off ◽

Low Volume ◽

Rain Events ◽

The Impact

Abstract. Due to climate change, cities need to adapt to changing rainfall and rainwater run-off dynamics. In order to develop an corresponding process based run-off model for pavements, we had to improve the measurement technique to detect run-off dynamics in an appropriate high resolution. Traditional tipping buckets (TB) have a comparable low volume resolution, capable to quantify the highest intensities in a range of expected flows. This results in varying temporal resolutions for varying flow intensities, especially in low resolutions for small flow events. Therefore, their applicability for run-off measurements and other hydrological process studies is limited, especially when the dynamics of both small and big flow events shall be measured. We improved a TB by coupling it to a balance and called it weighable tipping bucket (WTB). This paper introduces the device set up and the according data processing concept. The improved volume and temporal resolution of the WTB are demonstrated. A systematic uncertainty of TB measurements compared to WTB measurements is calculated. The impact of that increased resolution on our understanding of run-off dynamics from paved urban soils are discussed, exemplary for the run-off and the surface storage of a paved urban soil. The study was conducted on a permeably paved lysimeter situated in Berlin, Germany. Referring to the paved surface, the TB has a resolution of 0.1 mm, while the WTB has a resolution of 0.001 mm. The temporal resolution of the WTB is 3 s, the TB detects individual tippings with 0.4 s between them. Therefore, the data processing concept combines both the benefits of the balance to measure small intensities with that of the TB to measure high flow intensities. During a five months period (July to November 2009) 154 rain events were detected. Accordingly, the TB and WTB detected 47 and 121 run-off events. The total run-off was 79.6 mm measured by the WTB which was 11 % higher than detected by the TB. 95 % of that difference can be appointed to water, which evaporated from the TB. To derive a surface storage estimation, we analyzed the WTB and TB data for rain events without run-off. According to WTB data, the surface storage of the permeable pavement is 1.7 mm, while using TB data leads to an overestimation of 47 % due to low volume resolution of the TB. Combining traditional TB with modern, fast, high resolution digital balances offers the opportunity to upgrade existing TB systems in order to improve their volume detection limit and their temporal resolution, which is of great advantage for the synchronization of water balance component measurements and the investigation of hydrological processes. Furthermore, we are able to quantify the uncertainty of flow measurements gained with traditional tipping buckets.

Download Full-text