308 results on '"Compton scattering"'
Search Results
2. A compact and portable gamma-ray spectrometer (GRASP) for inertial confinement fusion and basic science experiments.
- Author
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Dannhoff, S. G., Wink, C. W., Mackie, S., Berg, G. P. A., and Frenje, J. A.
- Subjects
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MAGNETIC spectrometer , *MONTE Carlo method , *COMPTON scattering , *PERMANENT magnets , *SCIENTIFIC experimentation , *INERTIAL confinement fusion - Abstract
A compact and portable gamma-ray spectrometer has been designed to diagnose different components of the inertial confinement fusion-relevant γ-ray spectrum with energies between ∼3.7–17.9 MeV. The system is designed to be as compact as possible for convenient transportation and fielding in diagnostic ports on the OMEGA laser, the National Ignition Facility, and other photon-source facilities. The system consists of a conversion foil for Compton scattering in front of four magnetic spectrometer "arms," each covering a different energy range and constructed out of cylindrical permanent magnet Halbach arrays. Monte Carlo simulations have been used to optimize and assess the performance of the conversion foil, and COSY INFINITY ion-optical simulations have been used to optimize the spectrometer magnets. The performance of the design is assessed for a simulated direct-drive γ-ray spectrum. Spanning its total γ-ray energy bandwidth and using a 1.7 mm thick boron conversion foil, the system's total energy resolution and efficiency are ∼ 15.8 % –4.5% and 5.4 × 10−7–3.7 × 10−7e−/γ, respectively, with room for improvement. Spectral γ-ray measurements will provide guidance to the inertial confinement fusion program toward achieving high-energy gain relevant to inertial fusion energy and enable new measurement capabilities for basic discovery science. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Compact Compton γ-ray source from a spatiotemporal-modulated pulse scattering a high-energy electron beam.
- Author
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Yu, Q., Gu, Y. J., Zhang, Y., Kong, Q., and Kawata, S.
- Subjects
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COMPTON scattering , *PHOTON beams , *ELECTRON scattering , *MIRRORS , *RADIATION - Abstract
A novel plasma mirror is proposed for realizing all-optical Compton scattering, and its performance is compared with that of planar and concave plasma mirrors. Compared to a planar mirror, a concave mirror augments the radiation energy, but it decreases the collimation of the emitted photon beam. With the aid of the increased pulse length of the reflected laser, our proposed plasma mirror boosts the radiation energy and simultaneously improving the collimation of the emitted radiation. The pulse length and radius of the reflected laser can be controlled by adjusting the parameters of the proposed plasma mirror. The dependences of the pulse length and radius on the mirror parameters have been demonstrated. The impact of non-ideal conditions encountered in real experiments on the proposed mechanism has been discussed, which precisely demonstrates the robustness of the proposed mechanism. Additionally, the required gas density for a wakefield accelerator is derived to achieve optimal scattering under the given plasma mirror configurations. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. Determining effects of doping lithium nickel oxide with tungsten using Compton scattering.
- Author
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Kothalawala, Veenavee Nipunika, Suzuki, Kosuke, Li, Xin, Barbiellini, Bernardo, Nokelainen, Johannes, Makkonen, Ilja, Ferragut, Rafael, Tynjälä, Pekka, Laine, Petteri, Välikangas, Juho, Hu, Tao, Lassi, Ulla, Takano, Kodai, Tsuji, Naruki, Amada, Yosuke, Sasikala Devi, Assa Aravindh, Alatalo, Matti, Sakurai, Yoshiharu, Sakurai, Hiroshi, and Babar, Mohammad
- Subjects
NICKEL oxides ,TUNGSTEN ,COMPTON scattering ,LITHIUM-ion batteries ,ELECTRIC conductivity - Abstract
X-ray Compton scattering experiments along with parallel first-principles computations were carried out on LiNiO
2 to understand the effects of W doping on this cathode material for Li-ion batteries. By employing high-energy x rays exceeding 100 keV, an insight is gained into the fate of the W valence electrons, which are adduced to undergo transfer to empty O 2p energy bands within the active oxide matrix of the cathode. The substitution of W for Ni is shown to increase the electronic conductivity and to enhance the total magnetization per Ni atom. Our study demonstrates that an analysis of line shapes of Compton scattered x rays in combination with theoretical modeling can provide a precise method for an atomic level understanding of the nature of the doping process. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
5. Extracting the electronic structure of light elements in bulk materials through a Compton scattering method in the readily accessible hard x-ray regime.
- Author
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Kothalawala, Veenavee Nipunika, Guruswamy, Tejas, Quaranta, Orlando, Patel, Umeshkumar Manibhai, Gades, Lisa, Taddei, Keith, Yakovenko, Andrey, Zheng, Meiying, Morgan, Kelsey, Weber, Joel, Yan, Daikang, Swetz, Daniel, Makkonen, Ilja, Yeddu, Hemantha Kumar, Bansil, Arun, Ruett, Uta, Miceli, Antonino, Nokelainen, Johannes, and Barbiellini, Bernardo
- Subjects
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HARD X-rays , *COMPTON scattering , *ELECTRONIC structure , *LIGHT elements , *ELECTRON gas , *X-ray absorption near edge structure , *FREE electron lasers - Abstract
Our Compton profile measurements of Ti and TiH2 using readily available hard X-ray radiation at 27.5 keV, detected by both a Hitachi Vortex silicon-drift detector and a high-resolution superconducting transition-edge sensor array, are found to be in excellent accord with state-of-the-art density functional theory based calculations. The spherically averaged difference between the Compton profiles of TiH2 and Ti is well described by an inverted parabola, supporting an itinerant behavior of the electron gas screening the protons in the Ti matrix. Our experimental approach, validated by two different detectors, extends the applicability of Compton scattering technique to the readily accessible hard x-ray regime (below 30 keV). Our study suggests possibilities for experiments at low-flux bending magnet synchrotron beamlines and paves the way for the development of tabletop Compton experiments with x-ray tubes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. Manipulation of γ-ray polarization in Compton scattering.
- Author
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Wang, Yu, Ababekri, Mamutjan, Wan, Feng, Wen, Jia-Xing, Wei, Wen-Qing, Li, Zhong-Peng, Kang, Hai-Tao, Zhang, Bo, Zhao, Yong-Tao, Zhou, Wei-Min, and Li, Jian-Xing
- Subjects
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COMPTON scattering , *NUCLEAR physics , *ANGULAR momentum (Mechanics) , *POLARIZED photons , *MULTIPHOTON absorption , *ELECTRON beams - Abstract
High-brilliance high-polarization γ rays based on Compton scattering are of great significance in broad areas, such as nuclear physics, high-energy physics, astrophysics, etc. However, the transfer mechanism of spin angular momentum in the transition from linear through weakly into strongly nonlinear processes is still unclear, which severely limits the simultaneous control of brilliance and polarization of high-energy γ rays. In this work, we clarify the transfer mechanism in the transition regions and put forward a clear way to efficiently manipulate the polarization of emitted photons. We find that to simultaneously generate high-energy, high-brilliance, and high-polarization γ rays, it is better to increase the laser intensity for the initially spin-polarized electron beam. However, for the case of employing the initially spin-nonpolarized electron beam, in addition to increasing laser intensity, it is also necessary to increase the energy of the electron beam. Because the γ photon polarization emitted through the single-photon absorption channel is mainly attributed to the spin transfer of laser photons, while in multi-photon absorption channels, the electron spin plays a major role. Moreover, we confirm that the signature of γ-ray polarization can be applied to observing the nonlinear effects (multi-photon absorption) of Compton scattering with moderate-intensity laser facilities. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
7. Fully polarized Compton scattering in plane waves and its polarization transfer.
- Author
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Tang, Suo, Xin, Yu, Wen, Meng, Bake, Mamat Ali, and Xie, Baisong
- Subjects
PLANE wavefronts ,PHOTON scattering ,ELECTRON spin ,COMPTON scattering ,ELECTRON beams ,PHOTONS ,LASERS - Abstract
Fully polarized Compton scattering from a beam of spin-polarized electrons is investigated in plane-wave backgrounds in a broad intensity region from the perturbative to the nonperturbative regimes. In the perturbative regime, polarized linear Compton scattering is considered for investigating polarization transfer from a single laser photon to a scattered photon, and in the high-intensity region, the polarized locally monochromatic approximation and locally constant field approximation are established and are employed to study polarization transfer from an incoming electron to a scattered photon. The numerical results suggest an appreciable improvement of about 10% in the scattering probability in the intermediate-intensity region if the electron's longitudinal spin is parallel to the laser rotation. The longitudinal spin of the incoming electron can be transferred to the scattered photon with an efficiency that increases with laser intensity and collisional energy. For collision between an optical laser with frequency ∼1 eV and a 10 GeV electron, this polarization transfer efficiency can increase from about 20% in the perturbative regime to about 50% in the nonperturbative regime for scattered photons with relatively high energy. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
8. Scintillation characteristics of the EJ-299-02H scintillator.
- Author
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Floyd, N., Hassan, Md. T., Tang, Z., Krivoš, M., Blatnik, M., Cude-Woods, C., Clayton, S. M., Holley, A. T., Ito, T. M., Johnson, B. A., Liu, C.-Y., Makela, M., Morris, C. L., Navazo, A. S. C., O'Shaughnessy, C. M., Renner, E. L., Pattie, R. W., and Young, A. R.
- Subjects
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SCINTILLATORS , *ULTRACOLD neutrons , *BETA rays , *COMPTON scattering , *ELECTRON scattering , *THRESHOLD energy - Abstract
A study of the dead layer thickness and quenching factor of a plastic scintillator for use in ultracold neutron (UCN) experiments is described. Alpha spectroscopy was used to determine the thickness of a thin surface dead layer to be 630 ± 110 nm. The relative light outputs from the decay of 241Am and Compton scattering of electrons were used to extract Birks' law coefficient, yielding a kB value of 0.087 ± 0.003 mm/MeV, consistent with some previous reports for other polystyrene-based scintillators. The results from these measurements are incorporated into the simulation to show that an energy threshold of (∼9 keV) can be achieved for the UCNProBe experiment. This low threshold enables high beta particle detection efficiency and the indirect measurement of UCN. The ability to make the scintillator deuterated, accompanied by its relatively thin dead layer, gives rise to unique applications in a wide range of UCN experiments, where it can be used to trap UCN and detect charged particles in situ. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
9. Lasing below 170 nm using an oscillator FEL.
- Author
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Wu, Y. K., Mikhailov, S., Yan, J., Wallace, P., Popov, V., Pentico, M., Swift, G., Ahmed, M. W., Kochanneck, L., Ehlers, H., and Jensen, L. O.
- Subjects
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PROTECTIVE coatings , *QUANTUM chromodynamics , *COMPTON scattering , *UNDULATOR radiation , *STORAGE rings - Abstract
The short wavelength operation of free-electron laser (FEL) oscillators is limited by the availability of high-reflectivity, thermally stable, and radiation-resistant FEL mirrors in the vacuum UV (VUV) wavelength. We report our recent work to extend the shortest lasing wavelength of the oscillator FEL to 168.6 nm using a storage ring FEL. This progress has been made possible by developing a new FEL configuration with substantially reduced undulator harmonic radiation on the FEL mirror, a thermally stable FEL optical cavity, and a new type of high-reflectivity fluoride-based multilayer coating with a protective capping layer. Using these fluoride-based mirrors, we have demonstrated storage ring FEL lasing from 168.6 to 179.7 nm with excellent beam stability. Employing this VUV FEL in Compton scattering, we have produced the first 120 MeV gamma rays at the High Intensity Gamma-ray Source (HIGS). Operating the HIGS in this new high-energy region will create many new opportunities for photonuclear physics research, in particular, the low-energy quantum chromodynamics research. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
10. Simulations of laser-driven strong-field QED with Ptarmigan: Resolving wavelength-scale interference and γ-ray polarization.
- Author
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Blackburn, T. G., King, B., and Tang, S.
- Subjects
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COMPTON scattering , *ELECTRON beams , *PLANE wavefronts , *LASER beams , *LASERS - Abstract
Accurate modeling is necessary to support precision experiments investigating strong-field QED phenomena. This modeling is particularly challenging in the transition between the perturbative and nonperturbative regimes, where the normalized laser amplitude a0 is comparable to unity and wavelength-scale interference is significant. Here, we describe how to simulate nonlinear Compton scattering, Breit–Wheeler pair creation, and trident pair creation in this regime, using the Monte Carlo particle-tracking code Ptarmigan. This code simulates collisions between high-intensity lasers and beams of electrons or γ rays, primarily in the framework of the locally monochromatic approximation. We benchmark our simulation results against full QED calculations for pulsed plane waves and show that they are accurate at the level of a few per cent, across the full range of particle energies and laser intensities. This work extends our previous results to linearly polarized lasers and arbitrary polarized γ rays. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
11. Quantum splitting of electron peaks in ultra-strong fields.
- Author
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Zhang, Bo, Zhang, Zhi-Meng, and Zhou, Wei-Min
- Subjects
COMPTON scattering ,BREMSSTRAHLUNG ,ELECTRONS ,QUANTUM scattering ,ELECTRON scattering ,RADIATION ,LASERS - Abstract
Effects of multiple nonlinear Compton scattering on electrons in ultra-strong fields are described using analytic formulas similar to those in the theory of multiple bremsstrahlung. Based on these analytic formulas, a new pure quantum effect of multiple nonlinear Compton scattering called quantum peak splitting is identified: the electron peak splits into two when the average number of nonlinear Compton scatterings per electron passes a threshold of 5.1 and is below 9. Quantum peak splitting stems from the discreteness of quantum radiation reaction, with one of the split peaks being formed by electrons emitting zero to three times and the other by electrons emitting four or more times. This effect provides a new mechanism for the formation of electron peaks, imposes a new beamstrahlung limit on future colliders, and corrects the picture of quantum radiation reaction. Experiments can be performed on lasers with intensities ≳10
21 W/cm2 , which are reachable on PW-scale facilities. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
12. Highly polarized positrons generated via few-PW lasers.
- Author
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Li, Bing-Jun, Li, Yan-Fei, Chen, Yue-Yue, Weng, Xiu-Feng, Tan, Xin-Jian, Ma, Xin-Jie, Sheng, Liang, and Hu, Hua-Si
- Subjects
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POSITRONS , *FEMTOSECOND pulses , *POSITRON beams , *POSITRONIUM , *MONTE Carlo method , *COMPTON scattering , *LASERS - Abstract
Spin-polarized positron beams have widely been utilized in applications ranging from fundamental physical studies to material processing. Preparing highly polarized positron beams for accurate probing is a long-standing issue. Here, we put forward a method to produce ultra-relativistic polarized positrons with unprecedented purity in a femtosecond timescale employing a few-PW circularly polarized laser pulse. The fully spin-resolved QED Monte Carlo method is used for simulating the two successive QED processes during the interaction, i.e., nonlinear Compton scattering and nonlinear Breit–Wheeler pair production. As the photons emitted in a circularly polarized laser field are symmetrically polarized, the polarization of the intermediate gamma photon beam averages out to zero, which is advantageous for improving the polarization of positrons. Meanwhile, the moderate laser intensity suppresses the depolarization of the new-born positrons induced by radiation reaction effect. As a result, the polarization of the positrons can reach up to ≳ 90%, the highest among the laser-driven polarization schemes conceived hitherto. Furthermore, our method relaxes the requirement on laser intensity to few-PW level, offering a promising way of preparing polarized positrons with current-generation laser facilities. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
13. Structural and magnetic properties of superconductor NiBi3/α-Bi2O3 synthesized by mechanical alloying.
- Author
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Rebelo, Q. H. F., de Oliveira, A. E. S., Chaudhuri, P., Trichês, D. M., de Lima, J. C., and Michielon de Souza, S.
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COMPTON scattering , *MECHANICAL alloying , *MAGNETIC properties , *SUPERCONDUCTING transitions , *SUPERCONDUCTORS , *MAGNETIC susceptibility - Abstract
A nanostructured NiBi3/α-Bi2O3 superconductor composite has been synthesized by the process of mechanical alloying through 19 h of high energy ball milling. The kinetics of formation is analyzed in detail by x-ray diffraction and the Rietveld method. A simple method is proposed to determine the crystallinity of the resulting sample by using the background Rietveld fitting that permits a quantitative analysis of the diffuse x-ray profile taking into account the air and Compton scattering. The diffuse scattering is attributed to the formation of a nanocluster of α-Bi2O3 which is confirmed by high-resolution transmission electron microscopy and Raman measurements. The magnetic measurements show superconducting transition at around 4 K and the existence of NiBi3/α-Bi2O3 nanophases with a low irreversibility field at around 1.01 T at 2 K. Analysis of magnetic susceptibility and isothermal magnetic hysteresis of the NiBi3/α-Bi2O3 nanocomposite indicates the simultaneous existence of bulk superconductivity and ferromagnetism below 4 K. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
14. Determining effects of doping lithium nickel oxide with tungsten using Compton scattering.
- Author
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Kothalawala, Veenavee Nipunika, Suzuki, Kosuke, Li, Xin, Barbiellini, Bernardo, Nokelainen, Johannes, Makkonen, Ilja, Ferragut, Rafael, Tynjälä, Pekka, Laine, Petteri, Välikangas, Juho, Hu, Tao, Lassi, Ulla, Takano, Kodai, Tsuji, Naruki, Amada, Yosuke, Sasikala Devi, Assa Aravindh, Alatalo, Matti, Sakurai, Yoshiharu, Sakurai, Hiroshi, and Babar, Mohammad
- Subjects
NICKEL oxide ,TUNGSTEN ,COMPTON scattering ,LITHIUM-ion batteries ,ENERGY bands - Abstract
X-ray Compton scattering experiments along with parallel first-principles computations were carried out on LiNiO
2 to understand the effects of W doping on this cathode material for Li-ion batteries. By employing high-energy x rays exceeding 100 keV, an insight is gained into the fate of the W valence electrons, which are adduced to undergo transfer to empty O 2p energy bands within the active oxide matrix of the cathode. The substitution of W for Ni is shown to increase the electronic conductivity and to enhance the total magnetization per Ni atom. Our study demonstrates that an analysis of line shapes of Compton scattered x rays in combination with theoretical modeling can provide a precise method for an atomic level understanding of the nature of the doping process. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
15. Electron reflux dynamics in relativistically transparent plasma.
- Author
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Zhao, Yuan, Lu, Haiyang, Zhou, Cangtao, Zhang, Chunxiang, Liao, Meihua, Chen, Hailong, Zou, Zhengyu, Shang, Mengchen, and Yin, Siyuan
- Subjects
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PHOTON emission , *COMPTON scattering , *ELECTRONS , *PLASMA waves , *PONDEROMOTIVE force , *ELECTRON scattering , *ELECTRON beams , *PHASE space - Abstract
The electron re-injection effect has revealed the great probability rate of photon generation due to the head-on collision between relativistic electrons and laser. We study the electron re-injection dynamics when the ultra-intense laser irradiates the near-critical-density plasma and successfully controls the photon radiation by means of the transversely tailored plasma. Starting from the relativistic corrected ponderomotive force, the critical strength of the laser field required by the refluxing effect is theoretically obtained. Then, the theoretical description of the wavefront formed by electron refluxing is given via plugging in the difference in the transverse phase velocity of the plasma wave. Simulation results display a curved surface of the refluxing electrons, which are in good agreement with the calculation results stemming from the physics model. The re-built phase space of the refluxing electrons illustrates that they gain energy mainly from the longitudinal electrostatic field on the re-injection path. Despite the energy of the refluxing electron being relatively low, it could radiate more photons via more efficient non-linear Compton scattering than the electron being accelerated in the positive direction. Furthermore, we employ a transverse density profile in the plasma and successfully achieve control of the electron re-injection effect and the properties of the resultant photons as well. Simulation results exhibit that overcritical electron beams are successively re-injected from the plasma density peaks. These backward electrons emit photons along the two maximal plasma densities as they collide with the laser pulse. Although the quality of the photons is not improved, their spatial distribution is changed, which is a big step toward manipulating light sources. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
16. Study on SiPM GFAG scintillator for high time resolution Compton camera.
- Author
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Rachman, Agus Nur, Zhihong, Zhong, Donghwan, Kim, Uenomachi, Mizuki, Shimazoe, Kenji, Takahashi, Hiroyuki, Kishimoto, Takuya, Kogami, Hiroki, Mukai, Atsushi, Hara, Shintaro, Yamagishi, Keita, Tomita, Hideki, Tamura, Yusuke, Woo, Hanwool, Kamada, Kei, Ebi, Hidetake, Ishida, Fumihiko, Takada, Eiji, Asama, Hajime, and Kawarabayashi, Jun
- Subjects
- *
COMPTON imaging , *PHOTON detectors , *SIGNAL processing , *COMPTON scattering , *NUCLEAR industry , *SCINTILLATORS , *NUCLEAR counters - Abstract
Compton camera is a radiation detector that uses the kinematics of Compton scattering to estimate the direction of the gamma-ray incident. Compton camera has been used in many applications such as astronomy, medical, nuclear industry, and security. High time resolution in a Compton camera is essential to distinguish the incoming event in the detector. In this work, we developed a Compton camera using a fast decay scintillator and a high time resolution front end circuit to get a high-performance detector. The detector used an 8×8 multi-pixel photon counter (MPPC) array, which individually couple with a 2.5×2.5×5 mm3 GFAG (Gadolinium Fine Aluminum Gallate) scintillator. For processing the analog signal from the MPPC scintillators, the 64 channel ASIC (Application-Specific Integrated Circuit) is used. Each channel in the ASIC circuit consists of a pre-amplifier, shaper, monostable multivibrator, and slew-rate time over threshold. The ASIC will provide the digital output signal that contains the timing and energy information. The high-time resolution data acquisition circuit (PETnet) based on FPGA is used to acquire energy and time data from ASIC. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
17. Optical synchronization technique for all-optical Compton scattering.
- Author
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Kim, Do Yeon, Hojbota, Calin Ioan, Mirzaie, Mohammad, Lee, Seong Ku, Kim, Ki Yong, Sung, Jae Hee, and Nam, Chang Hee
- Subjects
- *
COMPTON scattering , *RELATIVISTIC electrons , *SYNCHRONIZATION , *LASER beams , *FEMTOSECOND lasers , *ELECTRON beams - Abstract
In all-optical Compton scattering driven by a multi-petawatt laser, it is critical to have accurate spatiotemporal synchronization between the ultrarelativistic electron bunch and the ultrahigh-intensity laser beam. Such a synchronization was realized by using two complementary optical setups. The first setup, used for the initial synchronization, recorded the spatial interferogram between the two femtosecond lasers used for a GeV electron beam production and an ultrahigh scattering laser beam. The second one, consisting of spatial and spectral interferometers, measured the time delay between the two laser beams in the range of 0–200 fs in real time. These monitoring systems played an essential role in conducting Compton scattering experiments. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
18. Compton sequence estimation based on the deep learning method.
- Author
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Jo, A., Kim, Y., and Lee, W.
- Subjects
- *
DEEP learning , *COMPTON imaging , *COMPTON scattering , *NUCLEAR counters , *PHOTOELECTRIC effect , *ELECTRONIC data processing - Abstract
Determining the sequence of Compton scattering and photoelectric absorption events for a Compton camera system through timing information is difficult due to the finite timing resolution of radiation detectors. The conventional method compares the energies of two sequential events and determines the order of these events. The deep learning method can estimate the sequence of Compton scattering followed by the photoelectric effect better than the conventional method because it determines the sequence based on both energy and positional information of the radiation interaction. The initial information of the deep learning models is the position and energy information, and the input data are then processed in the nodes of the hidden layers. In this study, the performance of deep learning models for Compton sequence estimation and the effect of position information on these methods were investigated. The accuracies of the deep learning method and the conventional comparison method were compared. The weights connecting each node were analyzed to evaluate the effects of position and energy information to determine the Compton sequence. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
19. Generation of collimated vortex gamma-rays from intense Poincaré beam–plasma interaction.
- Author
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Younis, D., Hafizi, B., and Gordon, D. F.
- Subjects
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COMPTON scattering , *ELECTRON scattering , *MOMENTUM transfer , *ANGULAR momentum (Mechanics) , *BREMSSTRAHLUNG , *ENERGY transfer - Abstract
We report on numerical calculations in which a multi-petawatt γ-ray beam is generated using a novel configuration based on fully structured light irradiating an overdense plasma waveguide. We analyze how the relativistic laser pulse efficiently confines and accelerates plasma electrons to GeV-scale energies and drives a quasi-static field that induces magneto-bremsstrahlung radiation. Multiphoton Compton scattering of electrons in the intense part of the laser also occurs although the radiated energy-density is comparatively lower. The emitted γ-rays carry orbital angular momentum, are highly collimated, and account for upwards of 15% of the incident field energy in one particular case. A comparison of the laser-to-particle angular momentum and energy transfer efficiencies is made between the cases of irradiation by a circularly polarized Laguerre–Gauss mode and one type of full Poincaré beam, and it is found that the latter yields an order-of-magnitude enhancement. The essential characteristics of the interaction are validated with three-dimensional particle-in-cell simulations that include quantum electrodynamical effects. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
20. Determination of the figurative point trajectory on the phase diagram of NiO lithiation–oxidation process by x-ray diffraction and Compton scattering methods.
- Author
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Mikhailov, Igor F., Gabielkov, Sergey.V., Mikhailov, Anton I., and Surovitskiy, Sergey.V.
- Subjects
- *
COMPTON scattering , *DIFFRACTIVE scattering , *PHASE diagrams , *X-ray diffraction , *PHASE equilibrium - Abstract
The positions of the figurative points on the triangular Gibbs phase diagram for the process of high-temperature synthesis of solid solutions LiyNi2−yO2 were determined for the first time using a combination of x-ray diffraction (XRD) and Compton scattering methods. The trajectory of the figurative point is built according to experimental data for temperatures of 650 and 750 °C. The ratios of the phases in equilibrium are found. It was established that, when the structure goes from rock salt to layered structures, the composition of the reagent mixture changes nonmonotonically: with an increase in the degree of ordering of the solid solution lattice, the sum molecular weight of the solid reagents increases. It has been shown experimentally that the combined use of XRD and Compton scattering makes it possible to carry out physicochemical analysis of the process and predict the final product. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
21. Parity-breaking parametric decay instability of kinetic Alfvén waves in a nonuniform plasma.
- Author
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Chen, Liu, Qiu, Zhiyong, and Zonca, Fulvio
- Subjects
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PLASMA Alfven waves , *PLASMA waves , *ION scattering , *COMPTON scattering , *MOMENTUM transfer - Abstract
We demonstrate that in a nonuniform plasma, the parametric decay instabilities of kinetic Alfvén waves could be quantitatively and qualitatively different from that in a uniform plasma. Specifically, the decay rate via ion Compton scattering is found to be enhanced, typically, by an order of magnitude. Furthermore, the parity of the decay kinetic Alfvén wave spectrum is broken, leading to finite net wave momentum transfer and, consequently, significant convective plasma transport with implications for confinement improvement. That localized absolutely unstable eigenmodes may be excited by a mode-converted pump wave is also presented. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
22. Tomography of atomic number and density of materials using dual-energy imaging and the Alvarez and Macovski attenuation model.
- Author
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Paziresh, M., Kingston, A. M., Latham, S. J., Fullagar, W. K., and Myers, G. M.
- Subjects
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ATOMIC number , *DUAL energy CT (Tomography) , *COMPTON scattering , *SIGNAL-to-noise ratio , *BEER-Lambert law - Abstract
Dual-energy computed tomography and the Alvarez and Macovski [Phys. Med. Biol. 21, 733 (1976)] transmitted intensity (AMTI) model were used in this study to estimate the maps of density (ρ) and atomic number (Z) of mineralogical samples. In this method, the attenuation coefficients are represented [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976)] in the form of the two most important interactions of X-rays with atoms that is, photoelectric absorption (PE) and Compton scattering (CS). This enables material discrimination as PE and CS are, respectively, dependent on the atomic number (Z) and density (ρ) of materials [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976)]. Dual-energy imaging is able to identify sample materials even if the materials have similar attenuation coefficients at single-energy spectrum. We use the full model rather than applying one of several applied simplified forms [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976); Siddiqui et al., SPE Annual Technical Conference and Exhibition (Society of Petroleum Engineers, 2004); Derzhi, U.S. patent application 13/527,660 (2012); Heismann et al., J. Appl. Phys. 94, 2073-2079 (2003); Park and Kim, J. Korean Phys. Soc. 59, 2709 (2011); Abudurexiti et al., Radiol. Phys. Technol. 3, 127-135 (2010); and Kaewkhao et al., J. Quant. Spectrosc. Radiat. Transfer 109, 1260-1265 (2008)]. This paper describes the tomographic reconstruction of ρ and Z maps of mineralogical samples using the AMTI model. The full model requires precise knowledge of the X-ray energy spectra and calibration of PE and CS constants and exponents of atomic number and energy that were estimated based on fits to simulations and calibration measurements. The estimated ρ and Z images of the samples used in this paper yield average relative errors of 2.62% and 1.19% and maximum relative errors of 2.64% and 7.85%, respectively. Furthermore, we demonstrate that the method accounts for the beam hardening effect in density (ρ) and atomic number (Z) reconstructions to a significant extent. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
23. Non-destructive measurement of in-operando lithium concentration in batteries via x-ray Compton scattering.
- Author
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Suzuki, K., Barbiellini, B., Orikasa, Y., Kaprzyk, S., Itou, M., Yamamoto, K., Yung Jui Wang, Hafiz, H., Uchimoto, Y., Bansil, A., Sakurai, Y., and Sakurai, H.
- Subjects
- *
LITHIUM cells , *X-rays , *COMPTON scattering , *QUANTUM theory , *PHYSICS - Abstract
Non-destructive determination of lithium distribution in a working battery is key for addressing both efficiency and safety issues. Although various techniques have been developed to map the lithium distribution in electrodes, these methods are mostly applicable to test cells. Here, we propose the use of high-energy x-ray Compton scattering spectroscopy to measure the local lithium concentration in closed electrochemical cells. A combination of experimental measurements and parallel first-principles computations is used to show that the shape parameter S of the Compton profile is linearly proportional to lithium concentration and thus provides a viable descriptor for this important quantity. The merits and applicability of our method are demonstrated with illustrative examples of LixMn2O4 cathodes and a working commercial lithium coin battery CR2032. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
24. Simplified derivation of the Kompaneets equation.
- Author
-
Milonni, Peter W.
- Subjects
- *
COMPTON scattering , *ELECTRON distribution , *COMPTON effect , *ELECTRON temperature , *ELECTROMAGNETIC fields , *DRAG force , *BOSE-Einstein condensation - Abstract
An isotropic electromagnetic field in a plasma of thermalized electrons undergoes changes in energy as a result of Compton scattering and an Einstein–Hopf drag force on the electrons, eventually approaching a Bose–Einstein photon distribution at the electron temperature. The rate of change of field energy due to the combined effects of Compton scattering and the drag force is shown to be described by the Kompaneets equation for photon diffusion in frequency space. A similarity is noted between this approach and Einstein's derivation of the Planck spectrum based on the recoil of atoms as they absorb and emit radiation. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
25. An application of a Si/CdTe Compton camera for the polarization measurement of hard x rays from highly charged heavy ions.
- Author
-
Tsuzuki, Yutaka, Watanabe, Shin, Oishi, Shimpei, Nakamura, Nobuyuki, Numadate, Naoki, Odaka, Hirokazu, Uchida, Yuusuke, Yoneda, Hiroki, and Takahashi, Tadayuki
- Subjects
- *
HEAVY ions , *X-rays , *ION recombination , *RELATIVISTIC electrodynamics , *COMPTON scattering , *POLARIMETRY , *HARD X-rays - Abstract
Methods to measure the polarization of x rays from highly charged heavy ions with a significantly higher accuracy than that of the existing technology are needed to explore relativistic and quantum electrodynamics effects, including the Breit interaction. We developed an Electron Beam Ion Trap Compton Camera (EBIT-CC), a new Compton polarimeter with pixelated multi-layer silicon, and cadmium telluride counters. The EBIT-CC detects the three-dimensional position of Compton scattering and photoelectric absorption, and thus, the degree of polarization of incoming x rays can be evaluated. We attached the EBIT-CC on the Tokyo Electron Beam Ion Trap (Tokyo-EBIT) in the University of Electro-Communications. An experiment was performed to evaluate its polarimetric capability through an observation of radiative recombination x rays emitted from highly charged krypton ions, which were generated by the Tokyo-EBIT. The CC of the EBIT-CC was calibrated for the ∼75 keV x rays. We developed event reconstruction and selection procedures and applied them to every registered event. As a result, we successfully obtained the polarization degree with an absolute uncertainty of 0.02. This uncertainty is small enough to probe the difference between the zero-frequency approximation and full-frequency-dependent calculation for the Breit interaction, which is expected for dielectronic recombination x rays of highly charged heavy ions. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
26. Compact broadband Compton spectroscopy used for intense laser-driven gamma rays.
- Author
-
Yang, Tao, Hu, Guang-yue, Li, Meng-ting, Lian, Chang-wang, Zhang, Zhen-chi, Luo, Wen, Ma, Yue, and Zheng, Jian
- Subjects
- *
COMPTON imaging , *MAGNETIC spectrometer , *COMPTON scattering , *MAGNETIC fields , *ELECTRON beams , *MAGNETS , *GAMMA rays , *GAMMA ray spectrometry - Abstract
A compact broadband Compton spectrometer is designed to measure the continuous spectrum of gamma-ray sources driven by an intense laser. The incident gamma rays are converted into electrons in low-Z materials by Compton scattering. Produced by a pair of stepped magnets, a weaker-front–stronger-rear nonuniform magnetic field in the electron magnetic spectrometer is used to spectrally resolve the scattered electrons, leading to a broadband gamma-ray spectral coverage of 2–20 MeV in a compact volume. Flat imaging-plate detectors are placed near the focused imaging points of the magnetic spectrometer to record the dispersed electrons, thereby achieving an optimal spectral resolution of 6%–13% in the energy range of 3–20 MeV. The spectrometer is used successfully to measure the gamma-ray spectrum generated by the high-energy electron beams produced by a femtosecond-laser-driven wakefield. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
27. Design of radiation conversion target for Compton gamma magnetic spectrometer.
- Author
-
Weng, Xiufeng, Tan, Xinjian, Hei, Dongwei, Zhang, Xiaodong, Sun, Bin, Wei, Kun, and Liu, Xiao
- Subjects
- *
MAGNETIC spectrometer , *ELECTRON distribution , *ANGULAR distribution (Nuclear physics) , *RADIATION , *GAMMA rays , *COMPTON scattering , *COMPTON electrons - Abstract
This paper analyzes the intrinsic energy resolution, the influence law of multiple Coulomb scattering, the radiation conversion efficiency, and other factors of the Compton radiation conversion target. Based on the essential principle of interaction between gamma rays and matter, the theoretical characteristics and transport law of Compton electrons are analyzed. Through a Monte Carlo simulation, the composition, energy, and angular distribution of electrons emitted from the target surface are calculated; the influence of target parameters, such as target material, thickness, and electron collection angle, on target performance is studied; and then the optimization method of target parameters is established. Finally, the main performance parameters of the Compton radiation conversion target are given. This research reveals how multiple Coulomb scattering angles relate to materials of different types and thicknesses, as well as to the optimal collection angle. A series of optimized parameters for the material, mass thickness, and corresponding energy resolution of radiation conversion target with different conversion efficiencies are obtained. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
28. Redox oscillations in 18650-type lithium-ion cell revealed by in operando Compton scattering imaging.
- Author
-
Suzuki, Kosuke, Suzuki, Shunta, Otsuka, Yuji, Tsuji, Naruki, Jalkanen, Kirsi, Koskinen, Jari, Hoshi, Kazushi, Honkanen, Ari-Pekka, Hafiz, Hasnain, Sakurai, Yoshiharu, Kanninen, Mika, Huotari, Simo, Bansil, Arun, Sakurai, Hiroshi, and Barbiellini, Bernardo
- Subjects
- *
COMPTON scattering , *X-rays , *OSCILLATIONS , *OXIDATION-reduction reaction , *LITHIUM-ion batteries , *BIOLUMINESCENCE - Abstract
Compton scattering imaging using high-energy synchrotron x rays allows the visualization of the spatiotemporal lithiation state in lithium-ion batteries probed in operando. Here, we apply this imaging technique to the commercial 18650-type cylindrical lithium-ion battery. Our analysis of the line shapes of the Compton scattering spectra taken from different electrode layers reveals the emergence of inhomogeneous lithiation patterns during the charge-discharge cycles. Moreover, these patterns exhibit oscillations in time where the dominant period corresponds to the timescale of the charging curve. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
29. Proton scalar polarizabilities from real Compton scattering data, using a bootstrap-based fitting technique.
- Author
-
Sconfietti, Stefano, Pasquini, Barbara, Pedroni, Paolo, Meyer, Curtis, and Schumacher, Reinhard A.
- Subjects
- *
COMPTON scattering , *DISPERSION relations , *PROTONS , *DATA analysis - Abstract
We present recent results on the extraction of the static scalar dipole polarizabilities (αE1 and βM1) from proton real Compton scattering (RCS) data below pion-production threshold. We focus on the fitting technique that is based on the parametric bootstrap. We show how to compute the realistic p-values, even when correlated and/or systematic uncertainties are present. We use the theoretical framework provided by fixed-t subtracted dispersion relations, which are obtained from the unitarity, causality and analyticity constraints of the RCS amplitudes. We obtain the numerical results: α E 1 = 12.03 − 0.54 + 0.48 , β M 1 = 1.77 − 0.54 + 0.52 (in 10−4 fm3 units), with p-value = 12%. Thanks to the new fitting technique, we are able to include in the data analysis both the systematic uncertainties and the experimental error of those parameters that are taken as input. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
30. The DVCS experiment in Hall C at Jefferson Lab with the new NPS detector.
- Author
-
Ko, Ho San, Meyer, Curtis, and Schumacher, Reinhard A.
- Subjects
- *
PARTONS , *COMPTON scattering , *DETECTORS , *ELECTRON beams , *PARTICLES (Nuclear physics) , *MAGNETS - Abstract
Deeply Virtual Compton Scattering (DVCS) is the simplest exclusive process to access Generalized Parton Distributions (GPDs). GPDs encode the correlation between the spatial distribution of partons inside the nucleon and their momentum. An upcoming DVCS experiment in Hall C at Jefferson Lab (Virginia, U.S.A.) will provide the highest precision data in a vast Q2-xB region accessible by an 11 GeV electron beam. It will further test the leading-twist dominance of the observables and get more precise data in the lower xB region needed for the full mapping of GPDs. A Neutral Particle Spectrometer (NPS) is being developed for this experiment. It consists of an electromagnetic calorimeter made of 1080 PbWO4 crystals and a sweeping magnet. This document will present the status of the detector R&D and construction, as well as simulation results of its performance. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
31. Current status of the LEPS2 experiment and commissioning of the solenoid spectrometer.
- Author
-
Ryu, Sun Young, Meyer, Curtis, and Schumacher, Reinhard A.
- Subjects
- *
COMPTON scattering , *CALORIMETERS , *SOLENOIDS , *SPECTROMETERS , *DATA acquisition systems , *DATABASES , *SCINTILLATORS , *PHOTON beams - Abstract
We report current status of the LEPS2 solenoid spectrometer for photoproduction experiments at SPring-8. A large solenoid LEPS2 spectrometer consists of a time projection chamber (TPC), drift chambers, resistive plate chambers and Pb/scintillator sampling calorimeters for photoproduction of hadrons in the energy range from 1.4 to 2.9 GeV. We have developed a new, network-distributed data acquisition system based on DAQ-middleware framework. The DAQ middleware components include gatherers collecting data from detector sub-systems, mergers integrating data from gatherers, and an event builder in the data acquisition software. Over ten thousand pad signals from the TPC are digitized with 40 MS 12-bit flash ADCs and then sent to a TPC gatherer through Space-Wire protocol. During the beam commissioning, Compton-backscattered photon beam was incident on a CH2 target in the energy region from 1.4 GeV to 2.4 GeV. We report on the performance test results of the new DAQ system with beam commissioning of the LEPS2 spectrometer as well. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
32. Measurement of the proton polarizabilities at MAMI.
- Author
-
Mornacchi, Edoardo, Meyer, Curtis, and Schumacher, Reinhard A.
- Subjects
- *
PION production , *ATOMIC physics , *POLARIZED photons , *DIFFERENTIAL cross sections , *COMPTON scattering , *INELASTIC scattering , *PHOTON beams - Abstract
Polarizabilities are fundamental properties related to the internal structure and dynamics of the nucleon. They play a crucial role not only in our understanding of the nucleon, but also in other areas such as atomic physics. The A2@MAMI Collaboration has undertaken a comprehensive program of real Compton scattering experiments in order to accurately determine these parameters at the Mainz Microtron (MAMI), using the Crystal Ball/TAPS setup. A new high quality data-set has been collected both on the differential cross section and on the beam asymmetry Σ3 below the pion production threshold using a polarized photon beam and an unpolarized liquid hydrogen target. This measurement will allow an extraction of the proton scalar polarizabilities αE1 and βM1 with a significant improvement to the large uncertainties of the present values. Moreover, the use of linearly and circularly polarized photon beams in conjunction with polarized targets will also allow an extraction of the different proton spin polarizabilities, which at the moment have only been determined in various linear combinations. To study these, the asymmetries Σ2x, Σ2z and Σ3 were measured above the pion production threshold. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
33. Studies Of The Polarization Of Gamma Photons Originating From The Decay of Positronium Atoms.
- Author
-
Sharma, Sushil K., Krawczyk, Nikodem, and Raj, Juhi
- Subjects
- *
POLARIZED photons , *POSITRONIUM , *PHOTON scattering , *COMPTON scattering , *PHOTON correlation , *ATOMS - Abstract
The precise measurements of the Compton scatterings of photons originating from the decay of positronium atoms can reveal information about their polarizations. J-PET detector is constructed of 192 plastic scintillators and is unique to study the scattering correlations of the annihilation photons with an angular precision of several degrees. In this work, we present the first experimental evidence showing the feasibility of measuring the photons relative polarization using the J-PET detector. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
34. Combined study of the ground and unoccupied electronic states of graphite by electron energy-loss spectroscopy.
- Author
-
Feng, Zhenbao, Löffler, Stefan, Eder, Franz, Su, Dangsheng, Meyer, Jannik C., and Schattschneider, Peter
- Subjects
- *
GRAPHITE , *ELECTRON energy loss spectroscopy , *TRANSMISSION electron microscopes , *COMPTON scattering , *ATOMIC scattering - Abstract
Both the unoccupied and ground electronic states of graphite have been studied by electron energy-loss spectroscopy in a transmission electron microscope. Electron energy-loss near-edge structures of the K-edge of carbon have been investigated in detail for scattering angles from 0 to 2.8 mrad. The π* and σ* components were separated. The angular and energy dependences of the π* and σ* structures were in fair agreement with theory. Electron energy loss Compton spectra of graphite were recorded at scattering angles from 45 to 68 mrad. One Compton scattering spectrum was obtained in 1 min compared with several hours or days using photons. The contributions of core electrons were calculated by the exact Hartree-Slater method in the Compton scattering region. The electron Compton profile for graphite is in good agreement with other conventional Compton profile measurements, as well as with theory, thus establishing the validity of the technique. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
35. Microscopic magnetic properties of an oxygen-doped Tb-Fe thin film by magnetic Compton scattering.
- Author
-
Agui, Akane, Unno, Tomoya, Matsumoto, Sayaka, Suzuki, Kousuke, Koizumi, Akihisa, and Sakurai, Hiroshi
- Subjects
- *
COMPTON scattering , *ATOMIC scattering , *THIN film research , *LIGHT scattering , *COHERENT backscattering - Abstract
The magnetic Compton scattering of a Tb32Fe55O13 film was measured in order to investigate the microscopic magnetization processes (i.e., the spin moment, orbital moment, and element specific moments). The trend of the spin magnetic moment was the same as that of the total magnetic moment but opposite to the orbital magnetic moment. In the low magnetic field region, the magnetic moments were not perfectly aligned perpendicular to the film surface, and the perpendicular components were found to mainly arise from the magnetic moment of Tb. Oxygen atoms hinder long range magnetic interaction and hence also affect the magnetization process of the magnetic moments of Tb and Fe. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
36. The effect of static many-body local-field corrections to inelastic electron scattering in condensed media.
- Author
-
Emfietzoglou, Dimitris, Kyriakou, Ioanna, Garcia-Molina, Rafael, and Abril, Isabel
- Subjects
- *
INELASTIC electron scattering , *INELASTIC scattering , *CONDENSED matter , *SCATTERING (Physics) , *COMPTON scattering - Abstract
We present a manageable approach to include, within the context of optical-data models of the dielectric response function, exchange and correlation (XC) effects in inelastic electron scattering, thus, going beyond the standard random-phase approximation (RPA). The many-body local-field correction in its static limit, G(q), is employed to incorporate XC effects to all orders in q at both the level of 'screening' and the level of 'scattering' by computing the so-called test-charge-test-charge (t-t), electron-test-charge (e-t), and electron-electron (e-e) dielectric functions. Some of the most used analytic approximations for G(q) are examined, ranging from the early Hubbard-like expressions to more recent parameterized formulations that satisfy some of the known asymptotic limits. The effect of the different G(q) models upon the inelastic scattering of low-medium energy electrons in condensed matter is examined using solid (amorphous) carbon as an example. It is shown that when XC corrections at all levels are considered, a net reduction of the inelastic scattering cross section by up to 20%-30% from the corresponding RPA value is obtained. Interestingly, a screened Hubbard approximation to G(q) reproduces (to a few %) the results of more accurate representations. Based on the present results, the controversial high-q asymptotic behaviour of G(q) is inconsequential to inelastic electron scattering in the examined energy range. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
37. Numerical scheme for evaluating the collision integrals for triple interactions in relativistic plasma.
- Author
-
Prakapenia, M. A., Siutsou, I. A., and Vereshchagin, G. V.
- Subjects
- *
RELATIVISTIC plasmas , *PLASMA interactions , *PLASMA equilibrium , *COMPTON scattering , *PAIR production , *BREMSSTRAHLUNG - Abstract
Binary interactions in relativistic plasma, such as Coulomb and Compton scattering as well as pair creation and annihilation are well known and studied in detail. Triple interactions, namely, relativistic bremsstrahlung, double Compton scattering, radiative pair production, and triple pair production and their inverse processes, are usually considered as emission processes in astrophysical problems, as well as in laboratory plasmas. Their role in plasma kinetics is fundamental [A. G. Aksenov et al., Phys. Rev. Lett. 99, 125003 (2007)]. We present a new conservative scheme for computation of the Uehling–Uhlenbeck collision integral for all triple interactions in relativistic plasma based on direct integration of exact QED matrix elements. Reaction rates for thermal distributions are compared, where possible, with the corresponding analytic expressions, showing good agreement. Our results are relevant for quantitative description of relativistic plasmas out of equilibrium, both under astrophysical and laboratory conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
38. Comparative study for intermediate crystal size of NaI(Tl) scintillation detector.
- Author
-
Singh, Inderjeet, Singh, Bhajan, Sandhu, B. S., and Sabharwal, Arvind D.
- Subjects
- *
SCINTILLATION counters , *COMPTON scattering , *CRYSTALS , *MATRIX inversion , *GAMMA functions , *SIGNAL-to-noise ratio - Abstract
The distinctive features of a well-known NaI(Tl) scintillation detector, by virtue of its crystal size, are experimentally investigated by observing changes in parameters such as intrinsic efficiency (εi), photo-peak efficiency (εp), resolution, and response function to incident gamma photon energy. This study provides a better understanding for the choice of crystal size of the scintillation detector in Compton scattering experiments. The response function of the NaI(Tl) detector is in the form of an inverse matrix focusing on the retort of the crystal when gamma photons are incident upon it. The response function of the NaI(Tl) detector depends upon the distance between the source and the detector, composition of the material for the crystal itself, photo-fraction, solid angle, incident gamma energy, and geometry of the experimental setup. The factors responsible for broadening of full energy and backscattered peaks are discussed for present investigations. The observed results indicate that the resolution of the detector varies with the incident energy of gamma radiation, and it also depends upon the size of the crystal of the detector. Statistical fluctuations related with the scintillation mechanism are found to be responsible for broadening of instrumental line width (photo-peak). The signal-to-noise ratio and photo-fraction for different crystal sizes of the scintillation detector corrected for efficiency of the detector are also discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
39. Dense high-energy γ-rays emission by ultra-intense laser interacting with a concave target.
- Author
-
Zhao, Yuan, Liu, Jianxun, Xia, Guoxing, and Bonatto, Alexandre
- Subjects
- *
CONCAVE surfaces , *COMPTON scattering , *HOT carriers , *LASERS , *LASER beams - Abstract
We propose to use a 10 petawatt (PW) laser irradiating onto a target with a concave surface, which can focus the laser beam and attain a more intense laser field, so as to increase both the yield and mean energy of emitted γ-rays. 2D particle-in-cell simulation results show that the peak electric field after the reflection of the laser from the target in this new scheme can reach ∼ 1.8 times as high as that in the plane target case. Such an enhanced laser field enables an increase in the number of hot electrons in front of the incident plane and raises the probability rate of generating high-energy γ-rays significantly by non-linear Compton scattering. As a result, 1.5 × 10 13 γ photons with a mean energy of 9.2 MeV are obtained. These photons mainly point toward two directions and distribute in pulses with the duration of each pulse of ∼ 400 as. A brightness as high as 3.6 × 10 25 photons / (mm 2 mrad 2 s 0.1 % BW) is obtained in one pulse. Compared to no positron observed for a plane target, a positron yield of 3.0 × 10 8 can be achieved in this new scheme. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
40. Depth dependence of spin-specific magnetization hysteresis loops measured by magnetic Compton scattering.
- Author
-
Tsuji, Naruki, Sakurai, Hiroshi, and Sakurai, Yoshiharu
- Subjects
- *
COMPTON scattering , *MAGNETIZATION , *MAGNETICS , *COERCIVE fields (Electronics) , *SURFACE area - Abstract
An application of magnetic Compton scattering to measure the depth dependence of spin-specific magnetization hysteresis (SSMH) loops in a Nd–Fe–B sintered magnet is presented herein. The depth dependence of SSMH was obtained by changing the position of x-rays with a vertical beam size of 10 μm. The results show that the surface deterioration area has a depth of 120 μm, where the magnetization begins to decrease gradually. In the internal region, we also observed decreased coercivity, which might be caused by the demagnetizing field. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
41. Ionizing radiation in electronics from the Compton scattering of quasi-stationary particles generated by characteristic and Bremsstrahlung x rays.
- Author
-
Min, Sun-Hong, Kwon, Ohjoon, Sattorov, Matlabjon, Kim, Seontae, Hong, Dongpyo, Kim, Seonmyeong, Cho, Ilsung, Park, Chawon, Jung, Wongyun, Kim, Minho, Kim, Kyeong Min, Hwang, Won Taek, Park, Seungwoo, Lee, Kyo Chul, Lee, Yong Jin, Lim, Sang Moo, Hong, Bong Hwan, and Park, Gun-Sik
- Subjects
- *
X-rays , *SCATTERING (Physics) , *BREMSSTRAHLUNG , *COMPTON scattering , *RELATIVISTIC electron beams , *ELECTROSTATIC accelerators , *IONIZING radiation , *ELECTRON beams - Abstract
Characteristic x rays generated by a collision between a tungsten target and relativistic electron beams generated from a compact electrostatic accelerator based on a Marx generator and a Blumlein pulse-forming line can induce transient ionizing radiation in electronics. While the decelerated electron beam is close to a collector out of range of an external magnetic field, Bremsstrahlung x rays occur at the same time. Compton scattering also occurs through secondary reaction interactions with quasi-stationary particles such as ejected inner shell electrons or photons. During a simulation, a semiconductor process is used to analyze the effects and processes of photocurrents derived from the flow of the drain current when transient pulses generated from the compact electrostatic accelerator are incident in the pMOSFET-AD420-based detector. The photocurrent induced from the detector is also measured by experimental results in comparison with a computer simulation, and a photocurrent detection experiment was then conducted with a high-pulse-current compact electrostatic accelerator. In addition, data pertaining to the irradiation dose rate and photon emission rate were obtained. In order to confirm the radiation pattern in the situation of Compton scattering, the ionizing radiation effect in the photosensitive phosphor was identified using a fluorescent lamp. During the experiment, a relativistic electron beam operating at high energy and current levels at a maximum of 1MeV-10 kA was utilized. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
42. The circular electron–positron collider beam energy measurement with Compton scattering and beam tracking method.
- Author
-
Tang, Guangyi, Chen, Shanhong, Chen, Yuan, Duan, Zhe, Ruan, Manqi, An, Guangpeng, Huang, Yongsheng, Lou, Xinchou, Zhang, Jianyong, Lan, Xiaofei, and Zhang, Chunlei
- Subjects
- *
COMPTON scattering , *MONTE Carlo method , *SYNCHROTRON radiation , *Z bosons , *STATISTICAL errors , *LASER pulses , *POSITRONS , *POSITRONIUM - Abstract
The beam energy of the circular electron–positron collider should be measured precisely to the order of 1 MeV, in order to decrease the uncertainty of the Higgs/W/Z bosons' mass measurement. For this purpose, a lepton bunch is extracted from the collider and collides with an Yttrium–Aluminum–Garnet laser pulse. After the inverse Compton scattering, the main beam and the scattered beam pass through an analytical magnetic field and are deflected to different angles. At the end of the drift beam pipes, the deflecting distances are detected with the spatial resolution of several microns. The systematic uncertainties caused by the detector arrangement, the magnetic field, the angle between the detector plane and the incident beam, and the synchrotron radiation are discussed in detail. The simulations of the statistical errors are given with a toy Monte Carlo sample. With some proper corrections, the beam energy uncertainty of the Higgs mode is around 2 MeV. Our method is applicable to different operating modes of the collider. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
43. Energy-resolved beam-monitoring system for undulator radiation using scattering from a chemical-vapor-deposition diamond film.
- Author
-
Kudo, Togo, Sano, Mutsumi, Itoga, Toshiro, Tajiri, Hiroo, Ozaki, Kyosuke, and Takahashi, Sunao
- Subjects
- *
COMPTON scattering , *UNDULATOR radiation , *WIGGLER magnets , *DIAMOND films , *NANODIAMONDS , *DIAMOND thin films , *SYNCHROTRON radiation , *CHEMICAL vapor deposition - Abstract
With low-emittance synchrotron radiation rings, introducing accurate x-ray beams to a sample is difficult, and ensuring that the direction of the undulator beam is stable is essential. However, measuring the centroid of the undulator photon beam at the beamline front-end (FE) is difficult because the soft x-ray radiation is contaminated by the bending magnets upstream and downstream of the undulator. The x-ray beam position monitors (XBPMs), based on the interaction with the halo of undulator radiation, cannot estimate the centroid of the beam, and they cannot eliminate the effects of the bending magnets. To solve this problem, we have developed an energy-resolved beam-monitoring system for undulator radiation with the scattering from a diamond thin film deposited by chemical vapor deposition (CVD) in this study. An undulator x-ray beam is irradiated onto this film, and its elastic and Compton scattering are observed through a 50 μm-diameter pinhole. A beam spot is detected through a pinhole camera system using a direct-detection-type charge-coupled device camera with energy resolution. The peak of the first-order harmonic of the undulator radiation is selectively visualized to measure the centroid of the undulator radiation, as well as the spectrum. The proposed system using a CVD diamond film can provide accurate position information for a photon beam exiting the FE. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
44. Enhancement-limit of Smith–Purcell radiation with self-bunched keV-order electron beam.
- Author
-
Annaka, Y., Ogura, K., Sato, Y., Nakasone, M., Rachi, K., Takahashi, T., and Hoshi, Y.
- Subjects
- *
COMPTON scattering , *RADIATION , *ELECTRON beams , *SURFACE enhanced Raman effect - Abstract
We studied enhanced Smith–Purcell (SP) radiation produced by a self-bunched keV-order electron beam based on a W-band surface-wave oscillator. The self-bunched beam is generated in the process of the beam interaction with the surface-wave mode. The bunched beam contains the second harmonic of the surface wave that enhances the SP radiation. The observed radiation shows that the enhancement is limited when the interaction transitions from the Compton regime to the Raman regime. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
45. Energy Calibration of Plastic Scintillator Detector.
- Author
-
Stríbrnský, Branislav, Petriska, Martin, and Hinca, Róbert
- Subjects
- *
SCINTILLATORS , *DETECTORS , *CALIBRATION , *COMPTON scattering , *ABSORPTION spectra , *POLYSTYRENE - Abstract
This paper is devoted to a plastic scintillator detector calibration method. We calibrated the large volume polystyrene gamma detector SPD200.200.100 by NUVIA Group. The essential issue of the plastic scintillator is that Compton scattering is the dominant effect of photon interaction within the detector and it is no apparent full energy absorption peak in a spectrum. Our approach is based on MCNP code simulation where the detector was modeled. Then measured and calculated spectra are compared to determine the Gaussian energy broadening effect. Finally, the measured spectra can be calibrated using Compton maximum and Compton edge energy. The results of this study show that measured and calculated spectra are in good agreement. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
46. Structural and Bonding Properties of Refractory TiC and ZrC: an Ab-initio Study.
- Author
-
Mund, H. S., Dhaka, Saroj, and Singh, V.
- Subjects
- *
COMPTON scattering , *GROUND state energy , *TRANSITION metal carbides , *BULK modulus , *ELECTRON density , *DENSITY functional theory , *ATOMIC orbitals , *AB-initio calculations - Abstract
Structural and bonding properties of transition metal carbides TiC and ZrC have been investigated using linear combination of atomic orbitals within framework of density functional theory. Density of states, bulk modulus, lattice parameters and pressure derivatives of the bulk modulus calculated at ground state energy are reported. The structure factors and real space Compton profiles (autocorrelation functions) of these materials are also discussed. The covalent bonding character of both the carbides has been discussed on the basis of structure factors, momentum densities and equal-valence-electron-density profiles. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
47. Deeply Virtual Compton Scattering with a Positron Beam.
- Author
-
Girod, François-Xavier, Elouadrhiri, Latifa, and Burkert, Volker D.
- Subjects
- *
COMPTON scattering , *ATOMIC scattering , *INELASTIC scattering , *COMPTON effect , *PHOTONS - Abstract
The hard electroproduction of a photon off a hadron in the Bjorken regime, Deeply Virtual Compton Scattering, unravels three-dimensional information on the partonic structure of the hadron. The imaginary part of the amplitude is more particularly sensitive to the spatial distribution of quarks as functions of the light cone momentum fraction. On the other hand, the real part of the amplitude is less constrained experimentally, and provides access to the D-term. Here we present preliminary results for the extraction of the D-term from unpolarized cross-sections and beam spin asymmetries measured with the CEBAF Large Acceptance Spectrometer at 6 GeV. We discuss some aspects of the associated physics interpretation, and give prospects for future measurements. The availability of a Positron beam at Jefferson Lab will provide access to the Beam Charge Asymmetry for this reaction, which will crucially enable us to keep under control the systematical and model uncertainties in this framework. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
48. Electronic structure and electron momentum densities of Ag2CrO4.
- Author
-
Meena, Seema Kumari, Ahuja, B. L., Shekhawat, Manoj Singh, Bhardwaj, Sudhir, and Suthar, Bhuvneshwer
- Subjects
- *
COMPTON scattering , *ELECTRONIC structure , *ATOMIC models , *DENSITY functionals , *ATOMIC orbitals , *DENSITY of states , *ENERGY bands , *CESIUM isotopes - Abstract
We present the first-ever experimental electron momentum density of Ag2CrO4 using 661.65 keV γ-rays from 20 Ci 137Cs source. To validate our experimental data, we have also deduced theoretical Compton profiles, energy bands and density of states using linear combination of atomic orbitals (LCAO) method in the framework of density functional theory. It is seen that the DFT-LDA gives a better agreement with experimental data than free atom model. The energy bands and density of states are also discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
49. Electronic structure and electron momentum densities of Ag2CrO4.
- Author
-
Meena, Seema Kumari, Ahuja, B. L., Shekhawat, Manoj Singh, Bhardwaj, Sudhir, and Suthar, Bhuvneshwer
- Subjects
COMPTON scattering ,ELECTRONIC structure ,ATOMIC models ,DENSITY functionals ,ATOMIC orbitals ,DENSITY of states ,ENERGY bands ,CESIUM isotopes - Abstract
We present the first-ever experimental electron momentum density of Ag
2 CrO4 using 661.65 keV γ-rays from 20 Ci137 Cs source. To validate our experimental data, we have also deduced theoretical Compton profiles, energy bands and density of states using linear combination of atomic orbitals (LCAO) method in the framework of density functional theory. It is seen that the DFT-LDA gives a better agreement with experimental data than free atom model. The energy bands and density of states are also discussed. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
50. X-ray sources using a picosecond laser driven plasma accelerator.
- Author
-
Lemos, N., King, P., Shaw, J. L., Milder, A. L., Marsh, K. A., Pak, A., Pollock, B. B., Goyon, C., Schumaker, W., Saunders, A. M., Papp, D., Polanek, R., Ralph, J. E., Park, J., Tommasini, R., Williams, G. J., Chen, Hui, Hartemann, F. V., Wu, S. Q., and Glenzer, S. H.
- Subjects
- *
LASER plasma accelerators , *COMPTON scattering , *PLASMA physics , *INERTIAL confinement fusion , *HARD X-rays , *X-rays , *ELECTRON beams , *BREMSSTRAHLUNG - Abstract
Laser-plasma-based accelerators are now able to provide the scientific community with novel high-energy light sources that are essential to study high-energy density matter, inertial confinement fusion, astrophysical systems, and fundamental plasma physics. Due to the transient and high-density properties of these systems, it is essential to develop light sources that are in the hard x-ray energy range (0.01–1 MeV) and directional and have high yield, low divergence, and short duration (ps and sub-ps). In this work, we show that by using a Laser plasma accelerator, it is possible to generate a broadband (0.01–1 MeV) hard x-ray source that satisfies the previous requirements. A series of experiments were conducted on the Titan laser at the Lawrence Livermore National Laboratory where a 10 nC electron beam in the 10–380 MeV energy range was generated through a laser plasma accelerator. The electrons generate x-rays via their betatron motion (few-30 keV) and hard x-rays through inverse Compton scattering (10–250 keV) and/or Bremsstrahlung (up to 1 MeV). Due to its unique characteristics, this source can be an important tool for many applications in large-scale international laser facilities. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
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