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Статті в журналах з теми "Electron momentum spectrometer"

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Автор: Grafiati

Опубліковано: 10 грудня 2022

Оновлено: 28 січня 2023

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1

TIXIER, S., Y. ZHENG, T. TIEDJE, G. COOPER, and C. E. BRION. "ELECTRON MOMENTUM SPECTROSCOPY OF SURFACES." Surface Review and Letters 06, no. 05 (October 1999): 579–84. http://dx.doi.org/10.1142/s0218625x99000524.

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Electron momentum spectroscopy [binary (e,2e) spectroscopy] using transmission geometry is a unique experimental tool for imaging the electron momentum distribution in gas phase samples as well as in thin films. In a solid, the electron momentum distribution is related to the band structure. Development of the (e,2e) technique using a more versatile reflection geometry is attractive since a much wider range of surfaces could be studied. The design of a new reflection (e,2e) spectrometer is presented. It is based on a two-step scattering model in which an incident electron successively reflects and ejects a valence electron from the surface. The scattered and ejected electrons are detected in coincidence and their energies and momentum vectors are simultaneously determined using a high throughput 90° truncated spherical electrostatic analyzer and position-sensitive detectors.

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2

Wallauer, Robert, Stefan Voss, Lutz Foucar, Tobias Bauer, Deborah Schneider, Jasmin Titze, Birte Ulrich, et al. "Momentum spectrometer for electron-electron coincidence studies on superconductors." Review of Scientific Instruments 83, no. 10 (October 2012): 103905. http://dx.doi.org/10.1063/1.4754470.

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3

Itou, Masayoshi, Shunji Kishimoto, Hiroshi Kawata, Makoto Ozaki, Hiroshi Sakurai, and Fumitake Itoh. "Development of an (X, eX) spectrometer for measuring the energies of the scattered photon and recoil electron." Journal of Synchrotron Radiation 5, no. 3 (May 1, 1998): 676–78. http://dx.doi.org/10.1107/s0909049597017913.

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The design and performance of a new spectrometer for coincidence measurements between the Compton scattered photon and the recoil electron are described. Coincidence measurements give direct information on the three-dimensional electron momentum density (EMD) of condensed matter. The present spectrometer measures energy spectra of both the photon and the electron. The energy spectrum of electrons is measured by a time-of-flight method using single-bunch operation at the Photon Factory Accumulator Ring (PF-AR). The energy resolution obtained for the recoil electron is 190 eV, which is better than that of the photon detector, so that a momentum resolution of the three-dimensional EMD of 0.3 atomic units can be achieved.

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4

Ahuja, Babu Lal, Harsh Malhotra, and Sonal Mathur. "Electron Momentum Density In Europium Using A 137Cs Compton Spectrometer." Zeitschrift für Naturforschung A 60, no. 7 (July 1, 2005): 512–16. http://dx.doi.org/10.1515/zna-2005-0708.

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The isotropic Compton profile of europium, the most reactive lanthanide, has been measured at a resolution of 0.40 a.u. using 661.65 keV gamma-rays. In the absence of a band structure-based Compton profile, the experimental data are compared with renormalised-free-atom (RFA) and free electron models. It is seen that the RFA model with e−-e− correlation agrees better with the experiment than the free electron models. The first derivatives of the Compton profiles show the hybridization effects of s-, p-, d-, f-electrons. From our RFA data we have also computed the cohesive energy of europium. PACS: 13.60.F, 71.15.Nc, 78.70. -g, 78.70.Ck

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5

Koop, Ivan. "Toroid spectrometer for electron-ion collider." International Journal of Modern Physics A 35, no. 34n35 (December 18, 2020): 2044021. http://dx.doi.org/10.1142/s0217751x20440212.

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In this paper, we present two options of the toroid magnetic spectrometer dedicated to measure the energy and the polar and the azimuthal angles of the scattered from the ion’s nuclear electrons in the future electron-ion collider DERICA at JINR. These options differ by the opposite sign of the magnetic field. In one of the options, the toroid magnetic field bends electrons towards the collision line, while in the option with the inverted field a bent is done outwards from the beam axis. We show that the last case provides much larger useful fraction of a solid angle for detection of the scattered electrons. The momentum resolution of such a spectrometer is estimated.

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6

Pang, W. N., and R. C. Shang. "Parallel data acquisition system for electron momentum spectrometer." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 434, no. 2-3 (September 1999): 444–48. http://dx.doi.org/10.1016/s0168-9002(99)00502-1.

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7

Weigold, E., YQ Cai, SA Canney, AS Kheifets, IE McCarthy, P. Storer, and M. Vos. "Direct Observation of EnergyMomentum Densities in Solids." Australian Journal of Physics 49, no. 2 (1996): 543. http://dx.doi.org/10.1071/ph960543.

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Анотація:

Electron momentum spectroscopy (EMS), based on kinematically complete observations of high energy electron impact ionisation events, directly observes energymomentum dispersion laws and densities of electrons in solids. The valence electronic structure in the near surface region, up to a depth of about 20 Å is probed for thin free-standing films (about 100 Å) by the multiparameter EMS spectrometer at Flinders University. The principles of the measurement are described and its application to the determination of energymomentum densities in a range of amorphous, polycrystalline and crystalline materials is discussed.

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8

Storer, P., R. S. Caprari, S. A. C. Clark, M. Vos, and E. Weigold. "Condensed matter electron momentum spectrometer with parallel detection in energy and momentum." Review of Scientific Instruments 65, no. 7 (July 1994): 2214–26. http://dx.doi.org/10.1063/1.1144730.

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9

Bozzini, J., and Y. Acremann. "Test signal generator for simulating electron events from a momentum microscope." Journal of Instrumentation 18, no. 01 (January 1, 2023): P01014. http://dx.doi.org/10.1088/1748-0221/18/01/p01014.

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Abstract Preparing experiments that utilize free electron lasers is challenging because obtaining access to the facility is difficult. The integration of detectors into the data acquisition system needs to be tested before the beamtime starts. In this study, we develop a test signal generator that simulates the signals from a delay-line detector used in a time-of-flight electron spectrometer. The output signals of the simulator are connected to the time-to-digital converter electronics and simulate a realistic energy spectrum of a real spectrometer. Through this method, the detector electronics can be tested and integrated into the data acquisition system at the free electron laser before the actual instrument is available on site. In addition, the saturation behavior of the signal processing chain can be tested by changing the number of simulated electrons per pulse.

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10

Chuan-Gang, Ning, Zhang Shu-Feng, Deng Jing-Kang, Liu Kun, Huang Yan-Ru, and Luo Zhi-Hong. "Improvements on the third generation of electron momentum spectrometer." Chinese Physics B 17, no. 5 (May 2008): 1729–37. http://dx.doi.org/10.1088/1674-1056/17/5/032.

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11

Takahashi, Masahiko, Taku Saito, Motoaki Matsuo, and Yasuo Udagawa. "A high sensitivity electron momentum spectrometer with simultaneous detection in energy and momentum." Review of Scientific Instruments 73, no. 6 (June 2002): 2242–48. http://dx.doi.org/10.1063/1.1473223.

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12

Ding, Bocheng, Weiqing Xu, Ruichang Wu, Yunfei Feng, Lifang Tian, Xiaohong Li, Jianye Huang, Zhi Liu, and Xiaojing Liu. "A Composite Velocity Map Imaging Spectrometer for Ions and 1 keV Electrons at the Shanghai Soft X-ray Free-Electron Laser." Applied Sciences 11, no. 21 (November 2, 2021): 10272. http://dx.doi.org/10.3390/app112110272.

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Velocity map imaging (VMI) spectrometry is widely used to measure the momentum distribution of charged particles with the kinetic energy of a few tens of electronVolts. With the progress of femtosecond laser and X-ray free-electron laser, it becomes increasingly important to extend the electron kinetic energy to 1 keV. Here, we report on a recently built composite VMI spectrometer at the Shanghai soft X-ray free-electron laser, which can measure ion images and high-energy electron images simultaneously. In the SIMION simulation, we extended the electron kinetic energy to 1 keV with a resolution <2% while measuring the ions with the kinetic energy of 20 eV. The experimental performance is tested by measuring Ar 2p photoelectron spectra at Shanghai Synchrotron Radiation Facility, and O+ kinetic energy spectrum from dissociative ionization of O2 by 800 nm femtosecond laser. We reached a resolution of 1.5% at the electron kinetic energy of 500 eV. When the electron arm is set for 100 eV, a resolution of 4% is reached at the ion kinetic energy of 5.6 eV. This composite VMI spectrometer will support the experiment, such as X-ray multi-photon excitation/ionization, Auger electrons emission, attosecond streaking.

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13

Qing, Qian, Xu Xiang-Yuan, Tian Jia-He, Zheng Yan-You, and Chen Xue-Jun. "Development of Electron Momentum Spectrometer and Study of Helium Structure." Acta Physico-Chimica Sinica 10, no. 05 (1994): 385–86. http://dx.doi.org/10.3866/pku.whxb19940501.

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14

Takahashi, Masahiko, and Yasuo Udagawa. "A high sensitivity electron momentum spectrometer with two-dimensional detectors and electron momentum distributions of several simple molecules." Journal of Electron Spectroscopy and Related Phenomena 137-140 (July 2004): 387–91. http://dx.doi.org/10.1016/j.elspec.2004.02.116.

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15

Manninen, S., V. Honkimäki, and P. Suortti. "Anisotropy of the Electron Momentum Distribution in Pyrolytic Graphite Studied Using a WKa1 Spectrometer." Zeitschrift für Naturforschung A 48, no. 1-2 (February 1, 1993): 295–98. http://dx.doi.org/10.1515/zna-1993-1-255.

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Abstract A new spectrometer construction based on a high-voltage W-anode x-ray tube has been used to measure the directional Compton profiles of a pyrolytic graphite crystal. Owing to the focusing geometry, the monochromatic WKα1 t beam is very well collimated, which improves the momentum resolution compared with conventional241 Am spectrometers, operated almost at the same energy. The experimental anisotropy in the basal plane and in the direction of the c-axis is found to be very close to that of a recent calculation, based on the pseudopotential local-density-functional model.

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16

Xue-Guang, Ren, Ning Chuan-Gang, Deng Jing-Kang, Zhang Shu-Feng, Su Guo-Lin, Li Bin, and Chen Xue-Jun. "A High-Efficiency Electron Momentum Spectrometer for Direct Imaging of Orbital Electron Density." Chinese Physics Letters 22, no. 6 (May 25, 2005): 1382–85. http://dx.doi.org/10.1088/0256-307x/22/6/023.

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17

Todd, B. R., N. Lermer, and C. E. Brion. "A high sensitivity momentum dispersive multichannel electron momentum spectrometer for studies in experimental quantum chemistry." Review of Scientific Instruments 65, no. 2 (February 1994): 349–58. http://dx.doi.org/10.1063/1.1145195.

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18

YANG BING-XIN, CHENG XIAN-JUN, PANG WEN-NING, CHENG MIAO-HUA, ZHANG FANG, TIAN BAO-LI, and XU KE-ZUN. "DEVELOPMENT STUDY OF (e,2e) ELECTRON MOMENTUM SPECTROMETER AND MEASUREMENT OF ELECTRON-MOMENTUM SPECTRUM OF SEVERAL ATOMS AND MOLECULARS." Acta Physica Sinica 46, no. 5 (1997): 862. http://dx.doi.org/10.7498/aps.46.862.

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19

Munjal, N., M. C. Mishra, G. Sharma, and B. K. Sharma. "Electron Momentum Density and Phase Transition in ZnS." Journal of Theoretical Chemistry 2013 (June 20, 2013): 1–7. http://dx.doi.org/10.1155/2013/349870.

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Анотація:

The electron momentum density distribution and phase transition in ZnS are reported in this paper. The calculations are performed on the basis of density functional theory (DFT) based on the linear combination of atomic orbitals (LCAO) method. To compare the theoretical Compton profile, the measurement on polycrystalline ZnS has been made using a Compton spectrometer employing 59.54 keV gamma rays. The spherically averaged theoretical Compton profile is in agreement with the measurement. On the basis of equal valence-electron-density Compton profiles, it is found that ZnS is less covalent as compared to ZnSe. The present study suggests zincblende (ZB) to rocksalt (RS) phase transition at 13.7 GPa. The calculated transition pressure is found in good agreement with the previous investigations.

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20

Yamazaki, M., H. Satoh, M. Ueda, D. B. Jones, Y. Asano, N. Watanabe, A. Czasch, O. Jagutzki, and M. Takahashi. "A highly sensitive electron momentum spectrometer incorporating a multiparticle imaging detector." Measurement Science and Technology 22, no. 7 (June 15, 2011): 075602. http://dx.doi.org/10.1088/0957-0233/22/7/075602.

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21

Bomme, C., R. Guillemin, T. Marin, L. Journel, T. Marchenko, D. Dowek, N. Trcera, et al. "Double momentum spectrometer for ion-electron vector correlations in dissociative photoionization." Review of Scientific Instruments 84, no. 10 (October 2013): 103104. http://dx.doi.org/10.1063/1.4824194.

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22

Ren, X. G., C. G. Ning, J. K. Deng, S. F. Zhang, G. L. Su, F. Huang, and G. Q. Li. "(e, 2e) electron momentum spectrometer with high sensitivity and high resolution." Review of Scientific Instruments 76, no. 6 (June 2005): 063103. http://dx.doi.org/10.1063/1.1897668.

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23

Davino, Michael, Edward McManus, Nora G. Helming, Chuan Cheng, Gönenç Moǧol, Zhanna Rodnova, Geoffrey Harrison, et al. "A plano–convex thick-lens velocity map imaging apparatus for direct, high resolution 3D momentum measurements of photoelectrons with ion time-of-flight coincidence." Review of Scientific Instruments 94, no. 1 (January 1, 2023): 013303. http://dx.doi.org/10.1063/5.0129900.

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Since their inception, velocity map imaging (VMI) techniques have received continued interest in their expansion from 2D to 3D momentum measurements through either reconstructive or direct methods. Recently, much work has been devoted to the latter of these by relating electron time-of-flight (TOF) to the third momentum component. The challenge is having a timing resolution sufficient to resolve the structure in the narrow (<10 ns) electron TOF spread. Here, we build upon the work in VMI lens design and 3D VMI measurement by using a plano–convex thick-lens (PCTL) VMI in conjunction with an event-driven camera (TPX3CAM) providing TOF information for high resolution 3D electron momentum measurements. We perform simulations to show that, with the addition of a mesh electrode to the thick-lens geometry, the resulting plano–convex electrostatic field extends the detectable electron cutoff energy range while retaining the high resolution. This design also extends the electron TOF range, allowing for a better momentum resolution along this axis. We experimentally demonstrate these capabilities by examining above-threshold ionization in xenon, where the apparatus is shown to collect electrons of energy up to ∼7 eV with a TOF spread of ∼30 ns, both of which are improved compared to a previous work by factors of ∼1.4 and ∼3.75, respectively. Finally, the PCTL-VMI is equipped with a coincident ion TOF spectrometer, which is shown to effectively extract unique 3D momentum distributions for different ionic species in a gas mixture. These techniques have the potential to lend themselves to more advanced measurements involving systems where the electron momentum distributions possess non-trivial symmetries.

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24

Moser, Daniel, Hartmut Abele, Joachim Bosina, Harald Fillunger, Torsten Soldner, Xiangzun Wang, Johann Zmeskal, and Gertrud Konrad. "NoMoS: An R × B drift momentum spectrometer for beta decay studies." EPJ Web of Conferences 219 (2019): 04003. http://dx.doi.org/10.1051/epjconf/201921904003.

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The beta decay of the free neutron provides several probes to test the Standard Model of particle physics as well as to search for extensions thereof. Hence, multiple experiments investigating the decay have already been performed, are under way or are being prepared. These measure the mean lifetime, angular correlation coefficients or various spectra of the charged decay products (proton and electron). NoMoS, the neutron decay products mo___mentum spectrometer, presents a novel method of momentum spectroscopy: it utilizes the R ×B drift effect to disperse charged particles dependent on their momentum in an uniformly curved magnetic field. This spectrometer is designed to precisely measure momentum spectra and angular correlation coefficients in free neutron beta decay to test the Standard Model and to search for new physics beyond. With NoMoS, we aim to measure inter alia the electron-antineutrino correlation coefficient a and the Fierz interference term b with an ultimate precision of Δa/a < 0.3% and Δb < 10−3 respectively. In this paper, we present the measurement principles, discuss measurement uncertainties and systematics, and give a status update.

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25

Tang, Yaguo, Xu Shan, Zhaohui Liu, Shanshan Niu, Enliang Wang, and Xiangjun Chen. "Development of an electron momentum spectrometer for time-resolved experiments employing nanosecond pulsed electron beam." Review of Scientific Instruments 89, no. 3 (March 2018): 033101. http://dx.doi.org/10.1063/1.5018665.

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26

Wang, EnLiang, Xu Shan, YuFeng Shi, YaGuo Tang, and XiangJun Chen. "Momentum imaging spectrometer for molecular fragmentation dynamics induced by pulsed electron beam." Review of Scientific Instruments 84, no. 12 (December 2013): 123110. http://dx.doi.org/10.1063/1.4847156.

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27

Krishnakumar, E., S. Denifl, I. Čadež, S. Markelj, and N. J. Mason. "Dissociative electron attachment cross sections for H2and D2using ion momentum imaging spectrometer." Journal of Physics: Conference Series 388, no. 5 (November 5, 2012): 052015. http://dx.doi.org/10.1088/1742-6596/388/5/052015.

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28

Oelmann, J. H., T. Heldt, L. Guth, J. Nauta, N. Lackmann, V. Wössner, S. Kokh, T. Pfeifer, and J. R. Crespo López-Urrutia. "Photoelectron tomography with an intra-cavity velocity-map imaging spectrometer at 100 MHz repetition rate." Review of Scientific Instruments 93, no. 12 (December 1, 2022): 123303. http://dx.doi.org/10.1063/5.0104679.

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We present a compact velocity-map imaging (VMI) spectrometer for photoelectron imaging at 100 MHz repetition rate. Ultrashort pulses from a near-infrared frequency comb laser are amplified in a polarization-insensitive passive femtosecond enhancement cavity. In the focus, multi-photon ionization (MPI) of gas-phase atoms is studied tomographically by rotating the laser polarization. We demonstrate the functioning of the VMI spectrometer by reconstructing photoelectron angular momentum distributions from xenon MPI. Our intra-cavity VMI setup collects electron energy spectra at high rates, with the advantage of transferring the coherence of the cavity-stabilized femtosecond pulses to the electrons. In addition, the setup will allow studies of strong-field effects in nanometric tips.

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29

Hamouda, Samir Ahmed. "Gamma-Ray Compton Spectroscopy for Determination of Electron Momentum Distributions in Iron." Advanced Materials Research 815 (October 2013): 8–12. http://dx.doi.org/10.4028/www.scientific.net/amr.815.8.

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Compton profile measurement of iron polycrystalline sample has been performed with 662 keV γ-radiation from a caesium-137 source. The spectrometer calibration and data corrections for the high energy experiment are discussed. The data are compared with the augmented-plane-wave (APW) and linear combination of atomic orbitals (LCAO) band theoretical Compton profiles of iron. Both theoretical predictions show the band theories overestimate the momentum density at low momenta and underestimate it at intermediate momenta.

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30

Mohammed, Sameen F., Abdulhadi Mirdan Ghaleb, and Esam S. Ali. "Electron Momentum Density of Nanoparticles ZrO2: A Compton Profile Study." International Journal of Nanoscience 20, no. 02 (January 19, 2021): 2150018. http://dx.doi.org/10.1142/s0219581x21500186.

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This work investigates the electronic momentum density (EMD) distribution in nanosize zirconia (ZrO2) using the technique of Compton scattering. The ZrO2 nanoparticles (11.2[Formula: see text]nm) are synthesized of mechanical milling and characterized by SEM, XRD and TEM probes. The Compton profile [Formula: see text] of nanoZrO2 is measured by Compton spectrometer 59.54[Formula: see text]KeV Gamma rays (Americium-241) source. The study finds out that EMD in nanoZrO2 is narrower comparing in case bulk ZrO2. This study adopts the ionic-model-based free atom [Formula: see text] calculation for many configurations (Zr)[Formula: see text](O[Formula: see text])2 ([Formula: see text]) to measure the charge transfer (CT) on the compound formation. According to this study’s findings, CT values in these materials are ranged from 1.5 to 1.0 electrons from Zr to O atom.

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31

Jiang, Wenbin, Xincheng Wang, Shuai Zhang, Ruichao Dong, Yuliang Guo, Jinze Feng, Zhenjie Shen, Zhiyuan Zhu, and Yuhai Jiang. "A Reaction Microscope for AMO Science at Shanghai Soft X-ray Free-Electron Laser Facility." Applied Sciences 12, no. 4 (February 10, 2022): 1821. http://dx.doi.org/10.3390/app12041821.

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We report on the design and capabilities of a reaction microscope (REMI) end-station at the Shanghai Soft X-ray Free-Electron Laser Facility (SXFEL). This apparatus allows high-resolution and 4π solid-angle coincidence detection of ions and electrons. The components of REMI, including a supersonic gas injection system, spectrometer, detectors and data acquisition system, are described in detail. By measuring the time of flight and the impact positions of ions and electrons on the corresponding detectors, three-dimensional momentum vectors can be reconstructed to study specific reaction processes. Momentum resolutions of ions and electrons with 0.11 a.u. are achieved, which have been measured from a single ionization experiment of oxygen molecules in an infrared (IR), femtosecond laser field, under vacuum at 1.2×10−10 torr, in a reaction chamber. As a demonstration, a Coulomb explosion experiment of oxygen molecules in the IR field is presented. These results demonstrate the performance of this setup, which provides a basic tool for the study of atomic and molecular reactions at SXFEL.

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32

QIAN, XIN. "SINGLE/DOUBLE-SPIN ASYMMETRY MEASUREMENTS OF SEMI-INCLUSIVE PION ELECTRO-PRODUCTION ON A TRANSVERSELY POLARIZED 3He TARGET THROUGH DEEP INELASTIC SCATTERING." Modern Physics Letters A 27, no. 21 (July 6, 2012): 1230021. http://dx.doi.org/10.1142/s0217732312300212.

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Parton distribution functions, which represent the flavor and spin structure of the nucleon, provide invaluable information in illuminating quantum chromodynamics in the confinement region. Among various processes that measure such parton distribution functions, semi-inclusive deep inelastic scattering is regarded as one of the golden channels to access transverse momentum dependent parton distribution functions, which provide a 3D view of the nucleon structure in momentum space. The Jefferson Lab experiment E06-010 focuses on measuring the target single and double spin asymmetries in the [Formula: see text] reaction with a transversely polarized 3 He target in Hall A with a 5.89 GeV electron beam. A leading pion and the scattered electron are detected in coincidence by the left High-Resolution Spectrometer at 16° and the BigBite spectrometer at 30° beam right, respectively. The kinematic coverage concentrates in the valence quark region, x ~ 0.1–0.4, at Q2 ~ 1–3 GeV 2. The Collins and Sivers asymmetries of 3 He and neutron are extracted. In this review, an overview of the experiment and the final results are presented. Furthermore, an upcoming 12-GeV program with a large acceptance solenoidal device and the future possibilities at an electron–ion collider are discussed.

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33

Lebedev, G., A. Tremsin, O. Siegmund, Y. Chen, Z. X. Shen, and Z. Hussain. "Complete momentum and energy resolved TOF electron spectrometer for time-resolved photoemission spectroscopy." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 582, no. 1 (November 2007): 168–71. http://dx.doi.org/10.1016/j.nima.2007.08.099.

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34

Ahuja, B. L., and N. L. Heda. "On a low intensity 241Am Compton spectrometer for measurement of electron momentum density." Pramana 68, no. 5 (May 2007): 843–50. http://dx.doi.org/10.1007/s12043-007-0082-9.

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35

DROUART, A., J. A. NOLEN, and H. SAVAJOLS. "SUPER SEPARATOR SPECTROMETER FOR THE LINAG HEAVY ION BEAMS." International Journal of Modern Physics E 18, no. 10 (November 2009): 2160–68. http://dx.doi.org/10.1142/s0218301309014482.

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The Super Separator Spectrometer (S3) will receive the very high intensity heavy ion beams from the LINAG accelerator of SPIRAL2. Its privileged fields of physics are the delayed study of rare nuclei and secondary reactions with exotic nuclei. The project is presently in a phase of conceptual design. It includes a rotating target to sustain the high energy deposit, a two stages separator (momentum achromat) and spectrometer (mass spectrometer). Various detection set-ups are foreseen, especially a delayed α, γ, and electron spectroscopy array and a gas catcher coupled to a low energy branch. We present here the current status of the project and its main features.

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36

Siddiki, Md Abul Kalam Azad, M. Nrishimhamurty, Kamal Kumar, Jibak Mukherjee, Lokesh C. Tribedi, Arnab Khan, and Deepankar Misra. "Development of a cold target recoil ion momentum spectrometer and a projectile charge state analyzer setup to study electron transfer processes in highly charged ion–atom/molecule collisions." Review of Scientific Instruments 93, no. 11 (November 1, 2022): 113313. http://dx.doi.org/10.1063/5.0100395.

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We report the development and performance of a cold target recoil ion momentum spectrometer (COLTRIMS) setup at TIFR, which is built to study various atomic and molecular processes involving the interaction of slow, highly charged ions from an electron cyclotron resonance based ion accelerator. We give a detailed description of the experimental setup, as well as report some initial results on the electron-capture process in collisions of Ar8+ ions with helium and carbon monoxide targets. Here, we present the longitudinal momentum transfer and the sub-shell resolved Q-value spectrum in the case of 2, 4, and 6 keV/u Ar8+ beams in collision with helium. A longitudinal momentum resolution of 0.27 a.u. is achieved in the present system. We also report the state-selective scattering angle distributions for all the collision systems under investigation. We further discuss the fragmentation of the CO2+ molecular ions for different electron capture channels for the 5 keV/u Ar8+ beam. The combination of the COLTRIMS, along with the beam cleaner, the electrostatic deflectors, and the charge state analyzer, is shown to have certain advantages.

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37

Wang, Y. Y., S. C. Cheng, and V. P. Dravid. "Momentum-resolved low-loss EELS in oxide superconductor." Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 988–89. http://dx.doi.org/10.1017/s042482010017267x.

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Valence band EELS spectra can be analyzed in terms of dielectric theory by Kramers-Kronig analysis. While dielectric function can also be obtained by optical techniques with higher energy resolution, EELS offers several advantages over the optical techniques: (i) transmission EELS is a bulk sensitive techniques and can provide dielectric function in a wide energy range (from infrared to soft x-ray); (ii) a large momentum (q) transfer in EELS, under favorable condition, can give rise to optical forbidden transitions; (iii) such q-resolved EELS spectra can be used to determine the localized (or otherwise) nature of excitations. In addition to that, a cold field emission gun (cFEG) electron microscopy (TEM) equipped with a parallel electron energy loss spectrometer provides a reasonable energy resolution (~0.5 eV), a small beam probe and a high counting rate, which eases conditions of sample preparation and makes certain EELS measurements more feasible to do, such as crystal orientation dependent dielectric function and dispersion of excitations in solids without acquiring a large size single crystal.

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38

MacKenzie, I. K. "Nondestructive analysis of thick-target specimens by γ-ray backscatter". Canadian Journal of Physics 67, № 8 (1 серпня 1989): 827–35. http://dx.doi.org/10.1139/p89-143.

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A multipurpose X- and γ-ray spectrometer for nondestructive analysis is described. It achieves high throughput through its axially symmetric geometry. Its evolution from a research program in positron annihilation is outlined as is its historical background in the determination of electron-momentum spectra. Several applications are discussed but special attention is paid to the nondestructive analysis of the new Canadian dollar coin.

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39

Tian, QiGuo, KeDong Wang, Xu Shan та XiangJun Chen. "A high-sensitivity angle and energy dipersive multichannel electron momentum spectrometer with 2πangle range". Review of Scientific Instruments 82, № 3 (березень 2011): 033110. http://dx.doi.org/10.1063/1.3568744.

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40

Suortti, P., T. Buslaps, P. Fajardo, V. Honkimäki, M. Kretzschmer, U. Lienert, J. E. McCarthy, et al. "Scanning X-ray spectrometer for high-resolution Compton profile measurements at ESRF." Journal of Synchrotron Radiation 6, no. 2 (March 1, 1999): 69–80. http://dx.doi.org/10.1107/s0909049599000291.

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A scanning-type crystal spectrometer for high-resolution Compton profile measurements has been constructed at the High Energy Inelastic Scattering Beamline (ID15B) of the ESRF. Radiation from a seven-period asymmetrical permanent-magnet wiggler or from a superconducting wavelength shifter is focused horizontally onto the sample by a bent-crystal monochromator. Typical energies are 30, 50 and 60 keV, the flux on the sample is 1012 photons s−1, and the relative energy bandwidth is 3 × 10−4. The spectrometer operates in the Rowland circle geometry, where the sample is fixed and the cylindrically bent analyser crystal and the detector move on the focusing circle by synchronized translations and rotations. The main detector is a large-diameter NaI scintillation counter, the incident beam is monitored by an Si diode, and scattering from the sample is detected using a Ge detector. The recorded spectrum is corrected for the energy-dependent response of the spectrometer, background and multiple scattering, and converted to the momentum scale. The resolution of the spectrometer is calculated from the geometrical factors and the reflectivity curve of the analyser crystal, and the result is checked against the widths of the elastically scattered line and fluorescent lines. So far, 0.1 a.u. resolution in electron momentum has been achieved. The typical average count rate over the Compton profile is about 1000 counts s−1 from a weakly absorbing sample.

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41

Graham, Lisa A., S. J. Desjardins, and A. D. O. Bawagan. "Coincidence electron-scattering experiments: the statistics of coincidence counting." Canadian Journal of Chemistry 71, no. 2 (February 1, 1993): 216–26. http://dx.doi.org/10.1139/v93-032.

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A new coincidence electron-scattering spectrometer for electron momentum spectroscopy (EMS) experiments is described. The new features include the use of a single 360° cylindrical mirror analyzer (CMA) for energy analysis and a coincidence data acquisition system based on a qVt-multichannel analyser and CAMAC electronics. The CMA energy resolution and coincidence time resolution are 0.32 ± 0.03% ΔE/E fwhm and 3.5 ± 0.5 ns fwhm, respectively. The helium 1s orbital binding energy spectrum is obtained at 1000 eV binding energy and 100 eV pass energy, yielding a coincidence binding energy resolution of 1.5 ± 0.2 eV fwhm. The coincidence data analysis procedure that is introduced provides experimental verification of some basic statistics of coincidence counting.

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42

Zheng, Y., G. Cooper, S. Tixier, B. R. Todd та C. E. Brion. "2π gas phase multichannel electron momentum spectrometer for rapid orbital imaging and multiple ionization studies". Journal of Electron Spectroscopy and Related Phenomena 112, № 1-3 (листопад 2000): 67–91. http://dx.doi.org/10.1016/s0368-2048(00)00203-6.

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43

Takahashi, M., and Y. Udagawa. "Development and use of a multichannel (e,2e) spectrometer for electron momentum densities of molecules." Journal of Physics and Chemistry of Solids 65, no. 12 (December 2004): 2055–59. http://dx.doi.org/10.1016/j.jpcs.2004.08.019.

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44

Vasilyev, D., and J. Kirschner. "Design and performance of a spin-polarized electron energy loss spectrometer with high momentum resolution." Review of Scientific Instruments 87, no. 8 (August 2016): 083902. http://dx.doi.org/10.1063/1.4961471.

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45

Ning, C. G., J. K. Deng, G. L. Su, H. Zhou, and X. G. Ren. "A multiparameter data acquisition system based on universal serial bus interface for electron momentum spectrometer." Review of Scientific Instruments 75, no. 9 (September 2004): 3062–64. http://dx.doi.org/10.1063/1.1781384.

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46

Itou, Masayoshi, Shunji Kishimoto, Hiroshi Kawata, Makoto Ozaki, Hiroshi Sakurai, and Fumitake Itoh. "Three Dimensional Electron Momentum Density of Graphite by (X, eX) Spectroscopy with a Time of Flight Electron Energy Spectrometer." Journal of the Physical Society of Japan 68, no. 2 (February 15, 1999): 515–20. http://dx.doi.org/10.1143/jpsj.68.515.

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47

Fry, J., R. Alarcon, S. Baeßler, S. Balascuta, L. Barrón Palos, T. Bailey, K. Bass, et al. "The Nab experiment: A precision measurement of unpolarized neutron beta decay." EPJ Web of Conferences 219 (2019): 04002. http://dx.doi.org/10.1051/epjconf/201921904002.

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Neutron beta decay is one of the most fundamental processes in nuclear physics and provides sensitive means to uncover the details of the weak interaction. Neutron beta decay can evaluate the ratio of axial-vector to vector coupling constants in the standard model, λ = gA/gV, through multiple decay correlations. The Nab experiment will carry out measurements of the electron-neutrino correlation parameter a with a precision of δa/a = 10−3 and the Fierz interference term b to δb = 3 × 10−3 in unpolarized free neutron beta decay. These results, along with a more precise measurement of the neutron lifetime, aim to deliver an independent determination of the ratio λ with a precision of δλ/λ = 0.03% that will allow an evaluation of Vud and sensitively test CKM unitarity, independent of nuclear models. Nab utilizes a novel, long asymmetric spectrometer that guides the decay electron and proton to two large area silicon detectors in order to precisely determine the electron energy and an estimation of the proton momentum from the proton time of flight. The Nab spectrometer is being commissioned at the Fundamental Neutron Physics Beamline at the Spallation Neutron Source at Oak Ridge National Lab. We present an overview of the Nab experiment and recent updates on the spectrometer, analysis, and systematic effects.

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48

Evans, Alan C., Jerry Mayers, David N. Timms, and Malcolm J. Cooper. "Deep Inelastic Neutron Scattering in the Study of Atomic Momentum Distributions." Zeitschrift für Naturforschung A 48, no. 1-2 (February 1, 1993): 425–32. http://dx.doi.org/10.1515/zna-1993-1-271.

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Abstract The electron-volt spectrometer (EVS) at the pulsed neutron source facility (ISIS) is being developed for the study of atomic momentum distributions. Neutrons with energies in the range 1 to 100 eV are incident on the sample, and the time-of-flight (TOF) spectrum of the scattered beam is measured by an array of fixed detectors. A resonant foil difference technique is used to yield a set of TOF spectra for those neutrons scattered into a fixed energy and through fixed angles. Information on the momentum distribution of the target nuclei can be deduced within an impulse approximation in a procedure analogous to that in Compton scattering of electrons by photons.Crystalline compounds containing aligned hydrogen bonds and other hydrogenous compounds are of particular interest owing to the high cross-section of the proton at these neutron energies. With improved statistical accuracy of the data it is anticipated that deviations of the proton's potential from a harmonic potential may be determined. Non-hydrogenous systems have also been investigated. A description is given of the basic theory and interpretive method. Data obtained on numerous systems are presented and discussed.

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49

Lermer, N., B. R. Todd, N. M. Cann, C. E. Brion, Y. Zheng, S. Chakravorty, and E. R. Davidson. "Electron momentum spectroscopy experiments and calculations for the production of excited states of He+ and." Canadian Journal of Physics 74, no. 11-12 (November 1, 1996): 748–56. http://dx.doi.org/10.1139/p96-108.

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The (e,2e) cross-section for transitions to the n = 2 final state of He+ and the 2sσg, final state of [Formula: see text] have been measured, relative to the cross-section for the transitions to the respective ground state ions, using a highly sensitive momentum dispersive multichannel electron momentum spectrometer. The experimental results for He are compared with plane wave impulse approximation (PWIA) cross-section calculations carried out using two previously published GI wavefunctions and also with two cross-section calculations based on explicitly correlated wavefunctions with energy errors of less than 10 nHartree. The H2 results are compared with calculations by J.W. Liu and V.H. Smith Jr. (Phys. Rev. A, 31, 3003 (1985); erratum: Phys. Rev. A, 39, 3703 (1989)). For both He and H2, significant differences are observed between the measured relative cross-sections and those calculated using the PWIA. While the measurements for He differ from previous work, the results for H2 are consistent with some earlier measurements.

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50

Ahuja, Babu Lal, Ashish Rathor, Vinit Sharma, Yamini Sharma, Ashvin Ramniklal Jani, and Balkrishna Sharma. "Electronic Structure and Compton Profiles of Tungsten." Zeitschrift für Naturforschung A 63, no. 10-11 (November 1, 2008): 703–11. http://dx.doi.org/10.1515/zna-2008-10-1114.

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The energy bands, density of states and Compton profiles of tungsten have been computed using band structure methods, namely the spin-polarized relativistic Korringa-Kohn-Rostoker (SPR-KKR) approach as well as the linear combination of atomic orbitals with Hartree-Fock scheme and density functional theory. The full potential linearized augmented plane wave scheme to calculate these properties and the Fermi surface topology (except the momentum densities) have also been used to analyze the theoretical data on the electron momentum densities. The directional Compton profiles have been measured using a 100 mCi 241Am Compton spectrometer. From the comparison, the measured anisotropies are found to be in good agreement with the SPR-KKR calculations. The band structure calculations are also compared with the available data.

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