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A new scheme is proposed that high energy electron beam as a probe is used for time resolved imaging measurement of high energy density materials, especially for high energy density matter and inertial confinement fusion. The first picosecond pulse-width electron radiography experiment was achieved by Institute of Modern Physics (IMP), Chinese Acad...
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... on the imaging criterion mentioned above, the other three samples, 50 meshes square Ni grid, 75 meshes hexagon Cu grid and 200 meshes square Cu grid, are well radiographed. The images are shown in Fig. 3. ...
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... RMS spatial resolution is an important parameter for radiography. The method of analysis is the same with reference [5]. In the image Fig. 3 (a), for 50 meshes Ni grid, 1 pitch corresponds to about 280 pixels, so 1 pixel equals to 1.79 um. With Gauss fit, the RMS spatial solution is 14.1 um, shown in Fig. 8. Because the magnetic strength of the triplets can be adjusted, with the different proper magnet strength, the different magnifying factor (MF) can be obtained. The MF will ...
Citations
... [6][7][8][9] A 30-MeV high-energy electron radiography system was first developed at Los Alamos National Laboratory and the Idaho Accelerator Center, achieving excellent spatial and temporal resolution, and 100 μm resolution imaging has been achieved using a tungsten filament and a fishing fly. 5 After that, much effort has been focused on the design of electron radiography systems with electron energies ranging from MeV to GeV, improving the spatial resolution to the submicrometer level and the temporal resolution to the picosecond level. 5,6,[10][11][12][13][14][15][16][17] Recently, 8.8-μm resolution imaging has been achieved at the Stanford Linear Accelerator Center (SLAC) through transmission high-energy electron microscopy (THEEM) using a 14-GeV electron beam to image the melting and freezing process of an alloy (Bi 80 Sn 20 ), which demonstrates the advantage of high energy electrons. 10 The charge and pulse duration of the electron bunch are of great importance in dynamic imaging. ...
A compact electron radiography system has been designed with high gradient permanent magnet quadrupoles with 2.5 times magnification. Quasi-monoenergetic electron bunches with energies ranging from 100 to 200 MeV are generated from a laser wakefield accelerator (LWFA) acting as the electron source for the system. A matching segment composed of three quadrupoles before the objective plane creates a correlation between the position and the angle for the electrons, illuminating the observed object improved the resolution of the system. We expect electron radiography with 100-MeV ultrafast electron bunches to be widely adopted for many applications, especially considering the micron-level spatial resolution and sub-picosecond temporal resolution of the electron source from the LWFA. Since the laser system needed for generating 100–200 MeV electrons using the LWFA is roughly around 40 TW, the whole system can be effectively table-top in size, which is favorable for movable applications.
... High-energy electron radiography (HEER) was proposed as a high spatial and temporal resolution probe tool for high-energy-density physics (HEDP) and inertial confinement fusion (ICF) experimental diagnostic studies [1,2]. In recent years, HEER technology was well developed through both simulations and experiments [3][4][5][6][7][8]. Radiography can be performed with a ps pulse-width electron beam, achieving a spatial resolution close to 1 µm in an experiment with a large magnification imaging lens [9]. ...
In this paper, we propose a new method for static mesoscale sample diagnosis using three-dimensional radiography with high-energy electron radiography (HEER). The principle of three-dimensional high-energy electron radiography (TDHEER) is elucidated, and the feasibility of this method is confirmed by start-to-end simulation results. TDHEER is realized by combining HEER with the three-dimensional reconstruction method, by which more information about the samples can be attained, especially regarding the samples’ internal structures. With our study, the internal structures and the three-dimensional positions of the spherical sample are determined with a ~3 μm resolution. We believe that this new method enhances the HEER diagnostic capability and extends its application potential in mesoscale sciences.
... This diagnosis technique uses a high energy electron beam as a probe for time-resolved and three-dimension spatial radiography diagnosis of the target. To validate the feasibility of HEER, some experiments have been performed by IMP and Tsinghua university and the results showed that this technique is a promising candidate for High Energy Density Physics diagnostics [4,5]. ...
We designed an electron linear accelerator (LINAC) for High Energy Electron Radiography (HEER) studies, which consists of two different guns, either a thermionic cathode or a photocathode RF gun, for diagnosing different targets. In this paper, we present the simulation studies and optimization of the LINAC based on an S-band thermionic RF gun. The LINAC is capable of generating sub-picosecond electron pulses with low energy spread (0.13%) and large micro-bunch charge (143 pC). The beam dynamics of the LINAC is studied and optimized by different beam dynamics simulation codes. The entrance hole induced field distortion in the alpha magnet is also reported. The space charge effects are studied by the General Particle Tracer (GPT) code. The results showed that the space charge forces had a significant influence on beam dynamics in such a low energy LINAC.
... High-energy electron radiography (HEER) was first developed by Los Alamos National Lab (Merrill et al., 2007) with a 30 MeV electron beam achieving spatial resolution on the order of 100 microns. The first picosecond pulse-width HEER experiment was demonstrated by the Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS), and Tsinghua University (THU), based on THU LINAC (Zhao et al., 2014a(Zhao et al., , 2016aZhou et al., 2017) with a 46 MeV beam and spatial resolution better than 10 microns, demonstrating proof of principle that this kind of LINAC with ultra-short pulse electron bunch can be used for HEER. ...
... The lens consists of two triplets. By tuning the imaging lens quadrupole strength, the three samples, 50 mesh square Ni grid, 75 mesh hexagon Cu grid, and 200 mesh square Cu grid, are well radiographed as shown by the images in Figure 3. Detailed experimental set up, results, and analysis can be found in Zhao et al. (2014a), which indicates that HEER is effective and has high-spatial resolution, better than 10 µm. ...
High-energy electron radiography (HEER) has been proposed for time-resolved imaging of materials, high-energy density matter, and for inertial confinement fusion. The areal-density resolution, determined by the image intensity information is critical for these types of diagnostics. Preliminary experimental studies for different materials with the same thickness and the same areal-density target have been imaged and analyzed. Although there are some discrepancies between experimental and theory analysis, the results show that the density distribution can indeed be attained from HEER. The reason for the discrepancies has been investigated and indicates the importance of the uniformity in the transverse distribution beam illuminating the target. Furthermore, the method for generating a uniform transverse distribution beam using octupole magnets was studied and verified by simulations. The simulations also confirm that the octupole field does not affect the angle-position correlation in the center part beam, a critical requirement for the imaging lens. A more practical method for HEER using collimators and octupoles for generating more uniform beams is also described. Detailed experimental results and simulation studies are presented in this paper.
... This method is fundamentally different from typical shadowgraphs with either charged particles or X/gamma rays. Several experiments have been performed with results in a good agreement with predications [10][11][12]. In general, those experiments required a dynamic process with a temporal resolution of ns, and a spatial resolution of sub micrometers. ...
Using a high energy electron beam for the imaging of high density matter with both high spatial-temporal and areal density resolution under extreme states of temperature and pressure is one of the critical challenges in high energy density physics . When a charged particle beam passes through an opaque target, the beam will be scattered with a distribution that depends on the thickness of the material. By collecting the scattered beam either near or off axis, so-called bright field or dark field images can be obtained. Here we report on an electron radiography experiment using 45 MeV electrons from an S-band photo-injector, where scattered electrons, after interacting with a sample, are collected and imaged by a quadrupole imaging system. We achieved a few micrometers (about 4 micrometers) spatial resolution and about 10 micrometers thickness resolution for a silicon target of 300-600 micron thickness. With addition of dark field images that are captured by selecting electrons with large scattering angle, we show that more useful information in determining external details such as outlines, boundaries and defects can be obtained.
... The first high-energy eRad experiment with picosecond pulsewidth was achieved by collaboration between the Institute of Modern Physics (IMP), the Chinese Academy of Sciences (CAS) and Tsinghua University (THU). The eRad system was based on the THU LINAC [4] with 46 MeV beam and the spatial resolution reached 10 mm, which demonstrated that this kind of LINAC with ultrashort pulse-width electron bunches can be used for eRad. Although the quadrupoles lenses for this radiographic experiment are not fully optimized, the experimental results, such as magnifying factor and the imaging distortion, agree very well with the beam optics theoretical results. ...
A beam line dedicated to high-energy electron radiography experimental research with linear achromat and imaging lens systems has been designed. The field of view requirement on the target and the beam angle-position correlation correction can be achieved by fine-tuning the fields of the quadrupoles used in the achromat in combination with already existing six quadrupoles before the achromat. The radiography system is designed by fully considering the space limitation of the laboratory and the beam diagnostics devices. Two kinds of imaging lens system, a quadruplet and an octuplet system are integrated into one beam line with the same object plane and image plane but with different magnification factor. The beam angle-position correlation on the target required by the imaging lens system and the aperture effect on the images are studied with particle tracking simulation. It is shown that the aperture position is also correlated to the beam angle-position on the target. With matched beam on the target, corresponding aperture position and suitable aperture radius, clear pictures can be imaged by both lens systems. The aperture is very important for the imaging. The details of the beam optical requirements, optimized parameters and the simulation results are presented.
... Many ultrafast imaging diagnostic tools are based on the use of hard X-rays, Gama rays, electron, proton, and carbon beams or even neutron beams produced by high power laser or other pulsed power like pinch device (Edwards et al., 2002;Beg et al., 2003;Li et al., 2008Li et al., , 2010Roth et al., 2013;Sheng et al., 2014;Zhao et al., 2014Zhao et al., , 2015. High energy proton radiography developed at Los Alamos National Laboratory (LANL) has shown its great potential for HED matter diagnostics with excellent spatial and temporal resolution (King et al., 1999;Merrill et al., 2011;Merrill, 2015). ...
We present a scheme of electron beam radiography to dynamically diagnose the high energy density (HED) matter in three orthogonal directions simultaneously based on electron Linear Accelerator. The dynamic target information such as, its profile and density could be obtained through imaging the scattered electron beam passing through the target. Using an electron bunch train with flexible time structure, a very high temporal evolution could be achieved. In this proposed scheme, it is possible to obtain 10
10
frames/second in one experimental event, and the temporal resolution can go up to 1 ps, spatial resolution to 1 µm. Successful demonstration of this concept will have a major impact for both future inertial confinement fusion science and HED physics research.
Here a compact three orthogonal planes high-energy electron radiography system was proposed. One of the critical technologies, the ultra-fast beam bunches split from the bunch train are studied. The separated bunches could be transported to the three orthogonal planes of the target for dynamic radiography diagnostics. The key elements of the ultra-fast bunches split system are transverse deflecting cavity (TDC) and the twin septum magnet (TSM). The principle of TDC and TSM are briefly introduced. An example of the beam bunches split system for test experiment (40 MeV electron beam) with TDC and TSM is designed and studied by particle-tracking simulation and it confirms this method is valid and feasible. Especially with TSM, a compact three orthogonal planes radiography system can be realized. The evolution of the beam parameters along the beam line from simulation are investigated. The detailed design of the beam split system and beam dynamics simulation study are presented in this paper.
