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A schematic view of an energy-recovery linac. An electron beam from the injector is accelerated by the superconducting linac and used for the gamma-ray generation. The energy of the spent electrons is recovered by deceleration in the superconducting linac.
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A nondestructive assay system for radioactive waste management is proposed. The system utilizes nuclear resonance fluorescence triggered by a quasi-monochromatic high-flux gamma ray generated from the Compton scattering of laser photons by relativistic electrons. We employ an energy-recovery linac as an electron source and a mode-locked fiber laser...
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... energy-recovery linac (ERL) is a novel type of accel- erator to generate an electron beam of high quality and high average current. Figure 3 is a schematic representative of an energy-recovery linac. In an energy-recovery linac, an elec- tron beam from an injector is accelerated by the time-vary- ing rf field stored in a superconducting linear accelerator and the beam is transported to a recirculation loop. ...
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Citations
... The setup was optimised to provide a 240 MeV electron beam colliding with a laser with a 515 nm wavelength [6]. This promises high intensity, small bandwidth 2 MeV photon beams suitable for nuclear resonance fluorescence (NRF) experiments [10]. ...
... This type of source makes it possible to obtain a compact (in comparison with a synchrotron) quasi-monochromatic (in comparison with bremsstrahlung radiation) beam of photons with controlled energy. It can be used to effectively determine stable and radioactive nuclides in a substance by scanning it with a beam of different energies and measuring the stimulated emission signal, which is unique for each nuclide [161]. ...
This review presents the author's view on modern trends in the development of charged particle accelerators for various applications, which is based on his own experience in this research field. The most promising, in the author's opinion, areas of application of resonance accelerators are shown, in which substantial progress has been made by using new technologies. The use of high-gradient structures, novel materials , new manufacturing technologies, cooling systems, and new principles of acceleration made it possible to achieve miniaturization, to increase cost efficiency, and to succeed in adjusting accelerator parameters (to achieve variability) for industrial, medical, and research purposes, as well as for applications in security systems and quantum computers.
... plays a critical role in nuclear safety [1], [2], nuclear waste management [3], and nonproliferation of nuclear materials [4], [5]. Bertozzi et al. [1] proposed the nuclear resonance fluorescence (NRF) process [6] with Bremsstrahlung gamma-ray beams for the measurement of the isotopes of interest. ...
... Owing to the dependence of the excitation energies on the nuclear species (isotope), the NRF assay can provide isotope-specific signatures for many materials [1]. NDA using NRF with a quasi-monochromatic gamma-ray beam generated through laser Compton scattering (LCS) on relativistic electron beams has been proposed previously [2], [3]. The LCS gamma-ray beam [9], [10] is characterized by properties such as energy tunability, quasi-monochromatic energy spectrum, controllable polarization, and strong directionality [11]- [13]. ...
The isotope selectivity of computed tomography (CT) imaging based on nuclear resonance fluorescence (NRF) transmission method using a quasi-monochromatic laser Compton scattering (LCS) gamma-ray beam in the MeV region was demonstrated at the UVSOR-III synchrotron radiation facility for two enriched lead isotope rods (206Pb and 208Pb) implanted in an aluminium cylinder. Since these two rods show the same gamma-rays attenuation in atomic processes, it is impossible to differentiate between them using a standard Gamma-CT technique based on atomic attenuation of gamma rays. The LCS gamma-ray beam had a maximum energy of 5.528 MeV and an intensity of approximately 5.5 photons/s/eV at the resonance energy (JΠ = 1-at 5.512 MeV in 208Pb). A lead collimator with a hole diameter of 1 mm was used to define the size of the LCS gamma-ray beam at the CT target. The CT image of the 208Pb rod was selectively obtained with a 2-mm pixel size resolution, which was determined by the horizontal step size of the CT stage.
... The radiation is emitted when the beam of ultra-relativistic particles undergoes planar channeling in PBC, such systems are called in literature 29 periodic bending of the atomic planes gives rise to strong, undulator-type CU radiation (CUR) in the photon energy range 0.1 -10 MeV. Light sources with this photon energy can be used in various new experimental and technological applications 16,[30][31][32][33] . ...
We analyze numerically the radiation and channeling properties of ultrarelativistic electrons and positrons propagating through a periodically bent diamond crystal grown on a straight single-crystal diamond substrate. Such systems can be called hetero-crystals and they are one of the experimentally realized samples for the implementation of crystalline undulators. We state that in such systems the channeling and radiation properties of projectiles are sensitive to the projectile particles energy and the beam propagation direction, i.e. on whether the beam of particles enters the crystal from the side of substrate or from the side of periodically bent crystal. The predictions made are important for design and practical realization of new crystalline undulators.
... Superconducting radio-frequency (SRF) electron guns are frequently considered to be the favorite pathway for generating the high-quality, high-current beams needed for broad scientific and industrial applications, such as driving high-power x-ray and extreme ultraviolet (EUV) continuous-wave (cw) free electron lasers (FELs) [1-10], intense γ-ray sources [11][12][13][14], coolers for hadron beams [15][16][17][18], and electron-hadron colliders [19][20][21]. The quality of the generated electron beams-both the intensity and brightness-is extremely important for many of these applications. ...
CW photoinjectors operating at high accelerating gradients promise to revolutionize many areas of science and applications. They can establish the basis for a new generation of monochromatic X-ray free electron lasers, high brightness hadron beams, or a new generation of microchip production. In this letter we report on the record-performing superconducting RF electron gun with $\textrm{CsK}_{2}\textrm{Sb}$ photocathode. The gun is generating high charge electron bunches (up to 10 nC/bunch) and low transverse emittances, while operating for months with a single photocathode. This achievement opens a new era in generating high-power beams with a very high average brightness.
... Moreover, this experimental result demonstrates that the distribution of the gamma-ray beam generated at the multiple collision points can be described as the superposition of the gamma-ray beams generated at each collision point. To increase the yield of monochromatic and wavelength-variable photon beams in the energy region above keV, multiple-collision FEL-Compton backscattering in an ERL facility will be a key technique [42,43]. We will advance the development of an insertion device which is suitable for backward Compton scattering using ERL-FELs. ...
We observed multiple-collision free-electron laser (FEL)-Compton backscattering in which a multi-bunch electron beam makes head-on collisions with multi-pulse FELs in an optical cavity, using an infrared FEL system in the storage ring NIJI-IV. It was demonstrated that the measured spectrum of the multiple-collision FEL-Compton backscattering gamma rays was the summation of the spectra of the gamma rays generated at each collision point. Moreover, it was demonstrated that the spatial distribution of the multiple-collision FEL-Compton backscattering gamma rays was the summation of those of the gamma rays generated at each collision point. Our experimental results proved quantitatively that the multiple collisions in the FEL-Compton backscattering process are effective in increasing the yield of the gamma rays. By applying the multiple-collision FEL-Compton backscattering to high-repetition FEL devices such as energy recovery linac FELs, an unprecedented high-yield gamma-ray source with quasi-monochromaticity and wavelength tunability will be realized.
... However, creation of the devices able to emit photons with sub-angstrom wavelength is still challenging. Meanwhile, such light sources open a number of new possibilities for various scientific experiments and technological applications such as various medical applications, photon induced disposing of a nuclear waste and nuclear reaction [3][4][5][6]. ...
In this paper we present the results of a systematic numerical analysis of the channeling properties for electrons and positrons in oriented straight and periodically bent diamond(110) crystals. We analyse the dependence of intensity of radiation emitted on the projectile energy as well as on the bending amplitude. The analysis presented is based on grounds of accurate numerical simulations of a channeling process. The simulation parameters, such as the crystal orientation, thickness and bending parameters of the crystals as well as the energy of the projectiles, were chosen to match those used in past and ongoing experiments. The peculiarities which appear in the radiation spectra are attributed to the interplay of various radiation mechanisms. The analysis performed can be used to predict and explain future experimental results.
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... However, gamma-ray sources which could not be generated from traditional synchrotron radiation are highly demanded by nuclear physics research in terms of fundamental physics research and nuclide detection [18,19]. Recently, many pioneering works in gamma-ray generation based on CBS have been carried out at Duke University, NewSUBARU, and Extreme Light Infrastructure-Nuclear Physics (ELI-NP) [20][21][22]. ...
As the development of nuclear physics and atomic sciences progresses, monochromatic and high-flux gamma-ray light sources are highly demanded by many experiments in these fields. We have designed a compact storage ring for gamma-ray source generation based on the Compton backscattering technique. The energy range of the electron beam stored in the ring will be from 500 to 800 MeV, with the capability of generating a gamma ray with an energy range from about 4 to 10 MeV. The maximum energy loss for an electron could be more than 1% for one scattering event, which could have a significant impact on electron beam dynamics. To study this impact, a 6D macroparticle tracking code has been developed by including the Compton scattering, damping, quantum excitation, and synchrotron radiation in the storage ring. The equilibrium states have been studied with this code, and the results show good agreement with theoretical predictions. The electron beam loss rate induced by Compton scattering has also been investigated by varying the input laser beam parameters. This study allows us to optimize the storage ring operation for a stable, high-flux, and narrow-bandwidth gamma-ray beam generation.
... Previous studies 6,7 have proposed a novel method to measure CT images for high density and high-Z objects based on identification of a specific nuclide with Nuclear Resonance Fluorescence (NRF), which is an interaction between a gamma ray and an atomic nucleus and has been studied for non-destructive analysis in industrial applications. [8][9][10][11][12] Hereafter, we call the CT imaging based on NRF as NRF-CT. If the energy of an incident gamma ray is identical with the energy of an excited level of a nucleus, the gamma ray is effectively absorbed by the nucleus, and subsequently the nucleus predominantly decays out by the emission of a gamma ray. ...
... The NRF with LCS gamma-ray beams has been proposed for nondestructive assay of hidden materials. [8][9][10] Kikuzawa et al. performed a proof-of-principle experiment for the NRF nondestructive analysis with LCS gamma-ray beams by measuring a lead block shielded by iron plates with a thickness of 1.5 cm. 11 This method can be extended to the nondestructive analysis of the chemical compounds of hidden materials, which was demonstrated by measuring a chemical compound of melamine hidden by an iron plate with a thickness of 1.5 cm and a lead plate with a thickness of 4 mm. ...
Computed Tomography (CT) using X-ray attenuation by atomic effects is now widely used for medical diagnosis and industrial non-destructive inspection. In this study, we performed a tomographic imaging of isotope ( ²⁰⁸ Pb) distribution by the Nuclear Resonance Fluorescence (NRF), i.e. isotope specific resonant absorption and scattering of gamma rays, using Laser Compton Scattering (LCS) gamma rays. The NRF-CT image which includes both effects of atomic attenuation and nuclear resonant attenuation was obtained. By accounting for the atomic attenuation measured by a conventional method at the same time, a clear ²⁰⁸ Pb isotope CT image was obtained. The contrast degradation due to notch refilling caused by small-angle Compton scattering is discussed. This study clearly demonstrates the capability of the isotope-specific CT imaging based on nuclear resonant attenuation which will be a realistic technique when the next generation of extremely intense LCS gamma-ray sources will be available. The expected image acquisition time using these intense LCS gamma rays was discussed.
... Superconducting radio-frequency (SRF) electron guns are frequently considered to be the favorite pathway for generating the high-quality, high-current beams needed for the future high-power energy-recovery linacs. SRF guns can find unique scientific and industrial applications, such as driving high-power X-ray and extreme ultraviolet (EUV) CW free electron lasers (FELs) [1-10], intense γ-ray sources [11][12][13][14], coolers for hadron beams [15][16][17][18], and electron-hadron colliders [19][20][21]. The quality of the generated electron beam-both its intensity and brightness-is extremely important for many of these applications. ...
Superconducting RF (SRF) photo-injectors are one of the most promising devices for generating continuous wave (CW) electron beams with record high brightness. Ultra-high vacuum of SRF guns provides for long lifetime of the high quantum efficiency (QE) photocathodes, while SRF technology provides for high accelerating gradients exceeding 10 MV/m. It is especially true for low frequency SRF guns where electrons are generated at photocathodes at the crest of accelerating voltage. Two main physics challenges of SRF guns are their compatibility with high QE photocathodes and multipacting. The first is related to a possibility of deposition of photocathode materials (such as Cs) on the walls of the SRF cavity, which can result in increased dark current via reduction of the bulk Nb work function and in enhancing of a secondary electron emission yield (SEY). SEY plays critical role in multipacting, which could both spoil the gun vacuum and speed up the deposition of the cathode material on the walls of the SRF cavity. In short, the multipactor behavior in superconducting accelerating units must be well understood for successful operation of an SRF photo-injector. In this paper we present our studies of 1.2 MV 113 MHz quarter-wave SRF photo-injector serving as a source of electron beam for the Coherent electron Cooling experiment (CeC) at BNL. During three years of operating our SRF gun we encountered a number of multipacting zones. We also observed that presence of $\textrm{CsK}_{2}\textrm{Sb}$ photocathode in the gun could create additional multipacting barriers. We had conducted a comprehensive numerical and experimental study of the multipactor discharge in our SRF gun, and had developed a process of crossing the multipacting barriers from zero to the operational voltage without affecting the lifetime of our photocathode and enhancing the strength of multipacting barriers.
