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1. The mechanisms and mechanics of the toughening of epoxy polymers modified with silica nanoparticles

Author

Stephan Sprenger, Ambrose C. Taylor, Anthony J. Kinloch, T. H. Hsieh, and Kunal Masania

Subjects
chemistry.chemical_classification, Toughness, Nanocomposite, Materials science, Polymers and Plastics, Organic Chemistry, Nanoparticle, Polymer, Epoxy, Fracture toughness, chemistry, visual_art, Materials Chemistry, visual_art.visual_art_medium, Composite material, Glass transition, Elastic modulus
Abstract

The present paper considers the mechanical and fracture properties of four different epoxy polymers containing 0, 10 and 20 wt.% of well-dispersed silica nanoparticles. Firstly, it was found that, for any given epoxy polymer, their Young’s modulus steadily increased as the volume fraction, v f, of the silica nanoparticles was increased. Modelling studies showed that the measured moduli of the different silica-nanoparticle filled epoxy polymers lay between upper-bound values set by the Halpin–Tsai and the Nielsen ‘no-slip’ models, and lower-bound values set by the Nielsen ‘slip’ model; with the last model being the more accurate at relatively high values of v f . Secondly, the presence of silica nanoparticles always led to an increase in the toughness of the epoxy polymer. However, to what extent a given epoxy polymer could be so toughened was related to structure/property relationships which were governed by (a) the values of glass transition temperature, T g , and molecular weight, M c , between cross-links of the epoxy polymer, and (b) the adhesion acting at the silica nanoparticle/epoxy-polymer interface. Thirdly, the two toughening mechanisms which were operative in all the epoxy polymers containing silica nanoparticles were identified to be (a) localised shear bands initiated by the stress concentrations around the periphery of the silica nanoparticles, and (b) debonding of the silica nanoparticles followed by subsequent plastic void growth of the epoxy polymer. Finally, the toughening mechanisms have been quantitatively modelled and there was good agreement between the experimentally-measured values and the predicted values of the fracture energy, G c , for all the epoxy polymers modified by the presence of silica nanoparticles. The modelling studies have emphasised the important roles of the stress versus strain behaviour of the epoxy polymer and the silica nanoparticle/epoxy-polymer interfacial adhesion in influencing the extent of the two toughening mechanisms, and hence the overall fracture energy, G c , of the nanoparticle-filled polymers.

Published
2010
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2. Simultaneous midline laser glossectomy with palatopharyngeal surgery for obstructive sleep apnoea syndrome

Author

Hsueh-Yu Li, S. W. Lee, T.-H. Hsieh, and Tuan-Jen Fang

Subjects
medicine.medical_specialty, medicine.diagnostic_test, business.industry, medicine.medical_treatment, Respiratory disease, Retrospective cohort study, General Medicine, Polysomnography, medicine.disease, Surgery, Male patient, Anesthesia, Respiratory disturbance index, medicine, Glossectomy, business, Adverse effect, Obstructive sleep apnoea syndrome
Abstract

We investigate the outcome of performing tongue base reduction surgery and palatopharyngeal surgery in a single stage to determine whether the same-stage midline laser glossectomy (MLG) with extended uvulopalatal flap (EUPF) for obstructive sleep apnoea syndrome (OSAS) is a safe and effective procedure. Six male patients with a history of severe OSAS were recruited into the retrospective study. They were the first patients to undergo the MLG with EUPF procedure. Patients were identified to have retropalatal and hypopharyngeal sites of obstruction on the basis of fiberoptic endoscopy with Muller's manoeuvre and three-dimensional computerised tomography. No significant adverse events occurred. The follow-up polysomnography (6-month follow-up) revealed that the mean respiratory disturbance index from 50.7 to 11.6, snoring index from 230.9 to 137.3 and the minimal oxygen saturation from 76.3 to 88.8. This study confirms that the same-stage MLG with EUPF for OSAS is a safe and effective procedure.

Published
2005
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3. PEDIATRICS LABORATORY RESEARCH

Author

V. Caretti, A. Noll, P. Woo, M. Monje, J. Cockle, A. Bruning-Richardson, S. Picton, J. Levesley, E. Ilett, S. Short, A. Melcher, S. Lawler, L. Garzia, A. Dubuc, G. Pitcher, P. Northcott, A. Mariampillai, S. Mack, K. Zayne, T. Chan, P. Skowron, X. Wu, A. Lionel, S. Morrisy, C. Hawkins, P. Kongkham, J. Rutka, A. Huang, A. Kenney, V. Yang, M. Salter, M. Taylor, S. Jelveh, P. Lindsay, D. Largaespada, L. Collier, A. Dupuy, R. Hill, T.-H. Hsieh, H.-W. Wang, W.-C. Cheng, T.-T. Wong, X. Huang, Y. He, R. Hashizume, W. Zhang, S. Stehbens, S. Younger, S. Barshow, S. Zhu, S. Mueller, W. Weiss, D. James, M. Shuman, Y. N. Jan, L. Jan, M. Marigil, P. Jauregi, M. A. Idoate, E. Xipell, G. Aldave, M. Gonzalez-Huarriz, S. Tejada-Solis, R. Diez-Valle, A. Montero-Carcaboso, J. Mora, M. M. Alonso, K. Taylor, A. Mackay, N. Truffaux, O. Morozova, Y. Butterfield, C. Phillipe, M. Vinci, C. de Torres, O. Cruz, D. Hargrave, S. Puget, S. Yip, C. Jones, J. Grill, A. Kaul, Y.-H. Chen, S. Dahiya, R. Emnett, S. Gianino, D. Gutmann, T. Miwa, S. Oi, Y. Nonaka, H. Sasaki, K. Yoshida, E. Lopez, A. P. de Leon, C. Sepulveda, L. Zarate, J. Diego-Perez, W. Pong, L. Ding, M. McLellan, I. Hussain, S. Higer, J. Leonard, A. Guha, E. Mardis, C. Sarkar, P. Pathak, P. Jha, S. Purkait, V. Sharma, M. C. Sharma, V. Suri, M. Faruq, M. Mukherjee, B. Sivasankaran, R. P. Velayutham, I. R. Fraschilla, K. J. Morris, T. J. MacDonald, T.-A. Read, D. Sturm, D. Jones, A. Korshunov, D. Picard, P. Lichter, S. Pfister, M. Kool, T.-W. Yao, J. Zhang, B. Anna, T. Brummer, N. Gupta, T. Nicolaides, K.-M. Chan, D. Fang, H. Gan, C. Yu, M. Schroeder, R. Jenkins, J. Sarkaria, and Z. Zhang

Subjects
Cancer Research, Engineering, Medical education, Abstracts, Oncology, business.industry, Neurology (clinical), business, Laboratory research
Published
2013

4. Quantifying nanoparticle dispersion: application of the Delaunay network for objective analysis of sample micrographs

Author

Ambrose C. Taylor, T. H. Hsieh, Kunal Masania, F. J. Guild, Steve Gilmour, and David J. Bray

Subjects
education.field_of_study, Micrograph, Microscope, Materials science, business.industry, Mechanical Engineering, Sample (material), Population, Magnification, Measure (mathematics), law.invention, Optics, Quality (physics), Mechanics of Materials, law, Dispersion (optics), General Materials Science, business, education
Abstract

Measuring quantitatively the nanoparticle dispersion of a composite material requires more than choosing a particular parameter and determining its correspondence to good and bad dispersion. It additionally requires anticipation of the measure’s behaviour towards imperfect experimental data, such as that which can be obtained from a limited number of samples. It should be recognised that different samples from a common parent population can give statistically different responses due to sample variation alone and a measure of the likelihood of this occurring allows a decision on the dispersion to be made. It is also important to factor into the analysis the quality of the data in the micrograph with it: (a) being incomplete because some of the particles present in the micrograph are indistinguishable or go unseen; (b) including additional responses which are false. With the use of our preferred method, this article investigates the effects on the measured dispersion quality of nanoparticles of the micrograph’s magnification settings, the role of the fraction of nanoparticles visible and the number of micrographs used. It is demonstrated that the best choice of magnification, which gives the clearest indication of dispersion type, is dependent on the type of nanoparticle structure present. Furthermore, it is found that the measured dispersion can be modified by particle loss, through the limitations of micrograph construction, and material/microscope imperfections such as cut marks and optical aberrations which could lead to the wrong conclusions being drawn. The article finishes by showing the versatility of the dispersion measure by characterising various different spatial features.

Published
2011

5. The Effect of Silica Nanoparticles and Carbon Nanotubes on the Toughness of a Thermosetting Epoxy Polymer

Author

T. H. Hsieh, Stephan Sprenger, Ambrose C. Taylor, and Anthony J. Kinloch

Subjects
Toughness, Materials science, Nanocomposite, Polymers and Plastics, Thermosetting polymer, Nanoparticle, General Chemistry, Carbon nanotube, Epoxy, Surfaces, Coatings and Films, law.invention, Fracture toughness, law, visual_art, Materials Chemistry, visual_art.visual_art_medium, Composite material, Glass transition
Abstract

Silica nanoparticles and multi-walled carbon nanotubes (MWCNTs) have been incorporated into an anhydride-cured epoxy-resin to form ‘hybrid’ nanocomposites. A good dispersion of the silica nanoparticles was found to occur, even at relatively high concentrations of the nanoparticles. However, in contrast, the MWCNTs were not so well dispersed but relatively agglomerated. The glass transition temperature of the epoxy polymer was 145°C, and was not significantly affected by the addition of the silica nanoparticles or the MWCNTs. The Young’s modulus was increased by the addition of the silica nanoparticles, but the addition of up to 0.18 wt% MWCNTs had no further significant effect. The addition of both MWCNTs and silica nanoparticles led to a significant improvement in the fracture toughness of these polymeric nanocomposites. For example, the fracture toughness was increased from 0.69 MPam 1/2 for the unmodified epoxy polymer to 1.03 MPam 1/2 for the hybrid nanocomposite containing both 0.18 wt% MWCNTs and 6.0 wt% silica nanoparticles; and the fracture energy was also increased from 133 J/m 2 to 204 J/m 2 . The mechanisms responsible for the enhancements in the measured toughness were identified by observing the fracture surfaces using field-emission gun scanning-electron microscopy.

Published
2011

6. Double-layer high-gain microstrip array antenna

Author

T.-H. Hsieh and Choon Sae Lee

Subjects
Patch antenna, Physics, Reconfigurable antenna, Directional antenna, Acoustics, Antenna aperture, Antenna measurement, law.invention, Microstrip antenna, law, Physics::Accelerator Physics, Dipole antenna, Electrical and Electronic Engineering, Computer Science::Information Theory, Metamaterial antenna
Abstract

Novel double-layer microstrip array antennas are introduced for high-gain applications. In the proposed antennas, the complex and lossy feed network is not needed. Rather the double structure provides the field distribution at the aperture for the beam-focusing effect. A relatively simple design method based on a cavity model is presented.

Published
2000
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7. Simultaneous midline laser glossectomy with palatopharyngeal surgery for obstructive sleep apnoea syndrome

Author

T-H, Hsieh, T J, Fang, H Y, Li, and S W, Lee

Subjects
Adult, Male, Sleep Apnea, Obstructive, Glossectomy, Humans, Pharynx, Laser Therapy, Middle Aged, Palate, Soft
Abstract

We investigate the outcome of performing tongue base reduction surgery and palatopharyngeal surgery in a single stage to determine whether the same-stage midline laser glossectomy (MLG) with extended uvulopalatal flap (EUPF) for obstructive sleep apnoea syndrome (OSAS) is a safe and effective procedure. Six male patients with a history of severe OSAS were recruited into the retrospective study. They were the first patients to undergo the MLG with EUPF procedure. Patients were identified to have retropalatal and hypopharyngeal sites of obstruction on the basis of fiberoptic endoscopy with Muller's manoeuvre and three-dimensional computerised tomography. No significant adverse events occurred. The follow-up polysomnography (6-month follow-up) revealed that the mean respiratory disturbance index from 50.7 to 11.6, snoring index from 230.9 to 137.3 and the minimal oxygen saturation from 76.3 to 88.8. This study confirms that the same-stage MLG with EUPF for OSAS is a safe and effective procedure.

Published
2005

8. Erratum to: The toughness of epoxy polymers and fibre composites modified with rubber microparticles and silica nanoparticles

Author

Stephan Sprenger, JS Lee, Ambrose C. Taylor, T. H. Hsieh, Kunal Masania, and Anthony J. Kinloch

Subjects
chemistry.chemical_classification, Toughness, Materials science, Mechanical Engineering, Epoxy, Polymer, Silica nanoparticles, Natural rubber, chemistry, Mechanics of Materials, visual_art, visual_art.visual_art_medium, General Materials Science, Composite material
Published
2011
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9. The effect of carbon nanotubes on the fracture toughness and fatigue performance of a thermosetting epoxy polymer

Author

Ambrose C. Taylor, Ian A. Kinloch, Anthony J. Kinloch, and T. H. Hsieh

Subjects
Nanotube, Materials science, Mechanical Engineering, Thermosetting polymer, Fracture mechanics, Mechanical properties of carbon nanotubes, Epoxy, Carbon nanotube, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, law.invention, Condensed Matter::Materials Science, Fracture toughness, Materials Science(all), law, Mechanics of Materials, visual_art, Void (composites), visual_art.visual_art_medium, General Materials Science, Composite material
Abstract

Multi-walled carbon nanotubes, with a typical length of 140 μm and a diameter of 120 nm, have been used to modify an anhydride-cured epoxy polymer. The modulus, fracture energy and the fatigue performance of the modified polymers have been investigated. Microscopy showed that these long nanotubes were agglomerated, and that increasing the nanotube content increased the severity of the agglomeration. The addition of nanotubes increased the modulus of the epoxy, but the glass transition temperature was unaffected. The measured fracture energy was also increased, from 133 to 223 J/m2 with the addition of 0.5 wt% of nanotubes. The addition of the carbon nanotubes also resulted in an increase in the fatigue performance. The threshold strain-energy release-rate, G th, increased from 24 J/m2 for the unmodified material to 73 J/m2 for the epoxy with 0.5 wt% of nanotubes. Electron microscopy of the fracture surfaces showed clear evidence of nanotube debonding and pull-out, plus void growth around the nanotubes, in both the fracture and fatigue tests. The modelling study showed that the modified Halpin–Tsai equation can fit very well with the measured values of the Young’s modulus, when the orientation and agglomeration of the nanotubes are considered. The fracture energy of the nanotube-modified epoxies was predicted, by considering the contributions of the toughening mechanisms of nanotube debonding, nanotube pull-out and plastic void growth of the epoxy. This indicated that debonding and pull-out contribute to the toughening effect, but the contribution of void growth is not significant. There was excellent agreement between the predictions and the experimental results.

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10. The toughness of epoxy polymers and fibre composites modified with rubber microparticles and silica nanoparticles

Author

Kunal Masania, Ambrose C. Taylor, Stephan Sprenger, T. H. Hsieh, Anthony J. Kinloch, and J. Sohn Lee

Subjects
chemistry.chemical_classification, Toughness, Materials science, Mechanical Engineering, chemistry.chemical_element, Nanoparticle, Thermosetting polymer, Fracture mechanics, Polymer, Epoxy, chemistry, Natural rubber, Mechanics of Materials, visual_art, visual_art.visual_art_medium, General Materials Science, Composite material, Carbon
Abstract

The present paper investigates the effect of adding silica nanoparticles to an anhydride-cured epoxy polymer in bulk and when used as the matrix of carbon- and glass-fibre reinforced composites. The formation of ‘hybrid’ epoxy polymers, containing both silica nanoparticles and carboxyl-terminated butadiene-acrylonitrile (CTBN) rubber microparticles, is also discussed. The structure/property relationships are considered, with an emphasis on the toughness and the toughening mechanisms. The fracture energy of the bulk epoxy polymer was increased from 77 to 212 J/m2 by the presence of 20 wt% of silica nanoparticles. The observed toughening mechanisms that were operative were (a) plastic shear-yield bands, and (b) debonding of the matrix from the silica nanoparticles, followed by plastic void-growth of the epoxy. The largest increases in toughness observed were for the ‘hybrid’ materials. Here a maximum fracture energy of 965 J/m2 was measured for a ‘hybrid’ epoxy polymer containing 9 wt% and 15 wt% of the rubber microparticles and silica nanoparticles, respectively. Most noteworthy was the observation that these increases in the toughness of the bulk polymers were found to be transferred to the fibre composites. Indeed, the interlaminar fracture energies for the fibre-composite materials were increased even further by a fibre-bridging toughening mechanism. The present work also extends an existing model to predict the toughening effect of the nanoparticles in a thermoset polymer. There was excellent agreement between the predictions and the experimental data for the epoxy containing the silica nanoparticles, and for epoxy polymers containing micrometre-sized glass particles. The latter, relatively large, glass particles were investigated to establish whether a ‘nano-effect’, with respect to increasing the toughness of the epoxy bulk polymers, did indeed exist.

11. High Statistics Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5–500 GeV with the Alpha Magnetic Spectrometer on the International Space Station

Author

K. H. Guo, A. Lebedev, Dong-Chul Son, Y. Y. Fan, Massimo Gervasi, L. Tao, M. Capell, L. Accardo, C. Sbarra, Yun Shi, Antje Putze, B. Coste, I. Guerri, H. Jinchi, D. Haas, V. Vagelli, G. La Vacca, A. Malinin, A. Piluso, R. Pilastrini, I. Cernuda, I. Lazzizzera, Carlos Díaz, W. De Boer, David Maurin, E. Valente, M. Bourquin, Laurent Derome, D. Grandi, M. Xie, I. Gebauer, X. M. Qi, G. Schwering, J. Bazo, P. G. Rancoita, M. S. Krafczyk, Wei Li, C. Mañá, E. Fiandrini, J. C. Marin, W. Gillard, T. Urban, V. Choutko, B. Bertucci, W. H. Sun, Q. Meng, R. Q. Xiong, Franck Cadoux, P. Nunes, Teimuraz Lomtadze, Fabrizio Giulio Luca Pilo, C. Türkoʇlu, G. Castellini, M. Bizzarri, Won Kyu Calvin Sun, P. Goglov, Mayda Velasco, Federico Cindolo, W. Y. Jang, S. S. Vaurynovich, H. S. Chen, F. Spinella, V. Cascioli, Benjamin Monreal, N. Nikonov, Liqiu Wang, Veronica Bindi, Kwangsoo Kim, Chia-Hui Lin, M. J. Chae, C. Guandalini, M. Duranti, E. Pedreschi, G. Boella, Sadakazu Haino, E. Laudi, Y. J. Yu, Lucio Rossi, S. Xie, G. Coignet, M. Paniccia, Xiaoping Wang, G. Laurenti, S. Zeissler, D. Schuckardt, V. Poireau, Q. H. Ye, J. Gong, F. Giovacchini, Roald Z. Sagdeev, Luca Morescalchi, D. Aisa, C. Goy, R. J. García-López, F. Palmonari, S. Della Torre, X. W. Tang, M. Pauluzzi, Samuel C.C. Ting, Y. H. Chang, Zhixiang Tang, Fei Zhou, F. Massera, Arturo Alejandro Menchaca-Rocha, S. M. Schmidt, G. Ambrosi, V. Vitale, M. Orcinha, J. Q. Li, Valery Zhukov, J. P. Vialle, K. Bollweg, Gongming Xin, H. L. Li, Markus Battarbee, Paolo Zuccon, L. Di Masso, G. Gallucci, L. Basara, G. Volpini, R. Clavero, T. Siedenburg, A. Rozhkov, E. Finch, J. H. Zhang, Davide Rozza, S. Lim, I. Rodríguez, L. Farnesini, S. Borsini, Claudio Corti, A. Fiasson, Z. M. Zheng, A. Obermeier, K. Andeen, A. Contin, D. D'Urso, Mingming Yang, J. Feng, M. Pohl, Z. L. Weng, D. Rapin, V. Plyaskin, E. Postaci, Zheng Wang, X. Y. Shi, Philipp Azzarello, Matthias Heil, Mauro Tacconi, B. S. Shan, J. Casaus, M. Graziani, T. Kirn, G. M. Cheng, Matteo Boschini, J. Wienkenhöver, N. Masi, F. Luo, A. I. Chen, Zhiqi Huang, L. Barrin, M. B. Demirköz, A. Papi, Z. H. He, F. Nozzoli, C. Zurbach, A. Alvino, Hengchang Liu, P. Lipari, S. Bizzaglia, T. X. Li, Varlen Grabski, C. Pizzolotto, T. Eronen, X. Xia, C. Consolandi, A. Schulz von Dratzig, K. Kanishev, Yu. Galaktionov, Lin Cheng, Nicola Tomassetti, Z. Q. Yu, D. C. Mo, Y. Li, W. Xu, Roberto Battiston, J. Berdugo, K. C. Han, S. C. Lee, H. T. Lee, Dong Liu, Behcet Alpat, R. Pereira, Q. L. Wang, S. Di Falco, H. Yi, B. Borgia, F. Spada, J. J. Torsti, S. Pensotti, Antonino Zichichi, S. M. Ting, C. Delgado, S. Schael, A. Ghelfi, S. S. Lv, J. Hoffman, N. Attig, F. Cervelli, Zhijun Zhang, P. Mott, J. Sandweiss, Henning Gast, Tim Martin, Y. H. Shan, G. Scolieri, J. Q. Ni, C. H. Chung, A. Oliva, M. T. Zhang, U. Becker, Fernando Barão, J. S. Ricol, M. Behlmann, D. Cerreta, Ningsheng Xu, Thomas Lippert, C. Leluc, F. J. Eppling, B. Beischer, V. Bonnivard, H. Y. Chou, R. Henning, R. D. Majka, M. Dai, Z. Cui, O. Kounina, G. Rybka, M. Müller, H. Wu, P. Saouter, Peter H. Fisher, K. Luebelsmeyer, D. Tescaro, M. Aguilar, Ruiguang Wang, F. Dimiccoli, K. Whitman, E. Choumilov, R. Kossakowski, G. N. Kim, H. L. Zhuang, A. Barrau, M. J. Lu, A. Bartoloni, Bruce Rafael Mellado Garcia, Luísa Arruda, M. Lolli, C. P. Tang, S. Kunz, A. Eline, Timothy H. Hsieh, J. Y. Shi, J. Yang, A. Chikanian, Gianpaolo Carosi, Changgi Huh, J. Z. Luo, Z. Y. Li, Lucio Quadrani, M. Habiby, A. Bachlechner, X. B. Zhang, Eun-Suk Seo, Ying Lu, S. Rosier-Lees, V. Koutsenko, Eino Valtonen, Z. H. Li, Qiang Li, J. D. Burger, W. J. Du, K. Y. Wu, Manuela Vecchi, C. Vannini, P. von Doetinchem, X. D. Cai, Giuseppe Levi, G. Martinez, C. Palomares, C. Clark, Andrei Kounine, Q. Yan, G. Bigongiari, S. Caroff, N. Zimmermann, M. Incagli, Maria Ionica, Azzarello, Philipp, Bourquin, Maurice, Cadoux, Franck, Haas, Daniel, Habiby Alaoui, Marion, Leluc, Catherine, Li, Yang, Paniccia, Mercedes, Pohl, Martin, Rapin, Divic Jean, Saouter, Pierre, Accardo, L, Aguilar, M, Aisa, D, Alpat, B, Alvino, A, Ambrosi, G, Andeen, K, Arruda, L, Attig, N, Azzarello, P, Bachlechner, A, Barao, F, Barrau, A, Barrin, L, Bartoloni, A, Basara, L, Battarbee, M, Battiston, R, Bazo, J, Becker, U, Behlmann, M, Beischer, B, Berdugo, J, Bertucci, B, Bigongiari, G, Bindi, V, Bizzaglia, S, Bizzarri, M, Boella, G, de Boer, W, Bollweg, K, Bonnivard, V, Borgia, B, Borsini, S, Boschini, M, Bourquin, M, Burger, J, Cadoux, F, Cai, X, Capell, M, Caroff, S, Carosi, G, Casaus, J, Cascioli, V, Castellini, G, Cernuda, I, Cerreta, D, Cervelli, F, Chae, M, Chang, Y, Chen, A, Chen, H, Cheng, G, Cheng, L, Chikanian, A, Chou, H, Choumilov, E, Choutko, V, Chung, C, Cindolo, F, Clark, C, Clavero, R, Coignet, G, Consolandi, C, Contin, A, Corti, C, Coste, B, Cui, Z, Dai, M, Delgado, C, Della Torre, S, Demirköz, M, Derome, L, Di Falco, S, Di Masso, L, Dimiccoli, F, Díaz, C, von Doetinchem, P, Du, W, Duranti, M, D’Urso, D, Eline, A, Eppling, F, Eronen, T, Fan, Y, Farnesini, L, Feng, J, Fiandrini, E, Fiasson, A, Finch, E, Fisher, P, Galaktionov, Y, Gallucci, G, García, B, García López, R, Gast, H, Gebauer, I, Gervasi, M, Ghelfi, A, Gillard, W, Giovacchini, F, Goglov, P, Gong, J, Goy, C, Grabski, V, Grandi, D, Graziani, M, Guandalini, C, Guerri, I, Guo, K, Haas, D, Habiby, M, Haino, S, Han, K, He, Z, Heil, M, Henning, R, Hoffman, J, Hsieh, T, Huang, Z, Huh, C, Incagli, M, Ionica, M, Jang, W, Jinchi, H, Kanishev, K, Kim, G, Kim, K, Kirn, T, Kossakowski, R, Kounina, O, Kounine, A, Koutsenko, V, Krafczyk, M, Kunz, S, LA VACCA, G, Laudi, E, Laurenti, G, Lazzizzera, I, Lebedev, A, Lee, H, Lee, S, Leluc, C, Levi, G, Li, H, Li, J, Li, Q, Li, T, Li, W, Li, Y, Li, Z, Lim, S, Lin, C, Lipari, P, Lippert, T, Liu, D, Liu, H, Lolli, M, Lomtadze, T, Lu, M, Lu, Y, Luebelsmeyer, K, Luo, F, Luo, J, Lv, S, Majka, R, Malinin, A, Mañá, C, Marín, J, Martin, T, Martínez, G, Masi, N, Massera, F, Maurin, D, Menchaca Rocha, A, Meng, Q, Mo, D, Monreal, B, Morescalchi, L, Mott, P, Müller, M, Ni, J, Nikonov, N, Nozzoli, F, Nunes, P, Obermeier, A, Oliva, A, Orcinha, M, Palmonari, F, Palomares, C, Paniccia, M, Papi, A, Pauluzzi, M, Pedreschi, E, Pensotti, S, Pereira, R, Pilastrini, R, Pilo, F, Piluso, A, Pizzolotto, C, Plyaskin, V, Pohl, M, Poireau, V, Postaci, E, Putze, A, Quadrani, L, Qi, X, Rancoita, P, Rapin, D, Ricol, J, Rodríguez, I, Rosier Lees, S, Rossi, L, Rozhkov, A, Rozza, D, Rybka, G, Sagdeev, R, Sandweiss, J, Saouter, P, Sbarra, C, Schael, S, Schmidt, S, Schuckardt, D, Schulz von Dratzig, A, Schwering, G, Scolieri, G, Seo, E, Shan, B, Shan, Y, Shi, J, Shi, X, Shi, Y, Siedenburg, T, Son, D, Spada, F, Spinella, F, Sun, W, Tacconi, M, Tang, C, Tang, X, Tang, Z, Tao, L, Tescaro, D, Ting, S, Tomassetti, N, Torsti, J, Türkoğlu, C, Urban, T, Vagelli, V, Valente, E, Vannini, C, Valtonen, E, Vaurynovich, S, Vecchi, M, Velasco, M, Vialle, J, Vitale, V, Volpini, G, Wang, L, Wang, Q, Wang, R, Wang, X, Wang, Z, Weng, Z, Whitman, K, Wienkenhöver, J, Wu, H, Wu, K, Xia, X, Xie, M, Xie, S, Xiong, R, Xin, G, Xu, N, Xu, W, Yan, Q, Yang, J, Yang, M, Ye, Q, Yi, H, Yu, Y, Yu, Z, Zeissler, S, Zhang, J, Zhang, M, Zhang, X, Zhang, Z, Zheng, Z, Zhou, F, Zhuang, H, Zhukov, V, Zichichi, A, Zimmermann, N, Zuccon, P, Zurbach, C, L. Accardo, M. Aguilar, D. Aisa, B. Alpat, A. Alvino, G. Ambrosi, K. Andeen, L. Arruda, N. Attig, P. Azzarello, A. Bachlechner, F. Barao, A. Barrau, L. Barrin, A. Bartoloni, L. Basara, M. Battarbee, R. Battiston, J. Bazo, U. Becker, M. Behlmann, B. Beischer, J. Berdugo, B. Bertucci, G. Bigongiari, V. Bindi, S. Bizzaglia, M. Bizzarri, G. Boella, W. d. Boer, K. Bollweg, V. Bonnivard, B. Borgia, S. Borsini, M. J. Boschini, M. Bourquin, J. Burger, F. Cadoux, X. D. Cai, M. Capell, S. Caroff, G. Carosi, J. Casau, V. Cascioli, G. Castellini, I. Cernuda, D. Cerreta, F. Cervelli, M. J. Chae, Y. H. Chang, A. I. Chen, H. Chen, G. M. Cheng, H. S. Chen, L. Cheng, A. Chikanian, H. Y. Chou, E. Choumilov, V. Choutko, C. H. Chung, F. Cindolo, C. Clark, R. Clavero, G. Coignet, C. Consolandi, A. Contin, C. Corti, B. Coste, Z. Cui, M. Dai, C. Delgado, S. D. Torre, M. B. Demirkoz, L. Derome, S. D. Falco, L. D. Masso, F. Dimiccoli, C. Diaz, P. v. Doetinchem, W. J. Du, M. Duranti, D. D'Urso, A. Eline, F. J. Eppling, T. Eronen, Y. Y. Fan, L. Farnesini, J. Feng, E. Fiandrini, A. Fiasson, E. Finch, P. Fisher, Y. Galaktionov, G. Gallucci, B. Garcia, R. Garcia-Lopez, H. Gast, I. Gebauer, M. Gervasi, A. Ghelfi, W. Gillard, F. Giovacchini, P. Goglov, J. Gong, C. Goy, V. Grabski, D. Grandi, M. Graziani, C. Guandalini, I. Guerri, K. H. Guo, D. Haa, M. Habiby, S. Haino, K. C. Han, Z. H. He, M. Heil, R. Henning, J. Hoffman, T. H. Hsieh, Z. C. Huang, C. Huh, M. Incagli, M. Ionica, W. Y. Jang, H. Jinchi, K. Kanishev, G. N. Kim, K. S. Kim, T. Kirn, R. Kossakowski, O. Kounina, A. Kounine, V. Koutsenko, M. S. Krafczyk, S. Kunz, G. L. Vacca, E. Laudi, G. Laurenti, I. Lazzizzera, A. Lebedev, H. T. Lee, S. C. Lee, C. Leluc, G. Levi, H. L. Li, J. Q. Li, Q. Li, T. X. Li, W. Li, Y. Li, Z. H. Li, Z. Y. Li, S. Lim, C. H. Lin, P. Lipari, T. Lippert, D. Liu, H. Liu, M. Lolli, T. Lomtadze, M. J. Lu, Y. S. Lu, K. Luebelsmeyer, F. Luo, J. Z. Luo, S. S. Lv, R. Majka, A. Malinin, C. Mana, J. Marin, T. Martin, G. Martinez, N. Masi, F. Massera, D. Maurin, A. Menchaca-Rocha, Q. Meng, D. C. Mo, B. Monreal, L. Morescalchi, P. Mott, M. Muller, J. Q. Ni, N. Nikonov, F. Nozzoli, P. Nune, A. Obermeier, A. Oliva, M. Orcinha, F. Palmonari, C. Palomare, M. Paniccia, A. Papi, M. Pauluzzi, E. Pedreschi, S. Pensotti, R. Pereira, R. Pilastrini, F. Pilo, A. Piluso, C. Pizzolotto, V. Plyaskin, M. Pohl, V. Poireau, E. Postaci, A. Putze, L. Quadrani, X. M. Qi, P. G. Rancoita, D. Rapin, J. S. Ricol, I. Rodriguez, S. Rosier-Lee, L. Rossi, A. Rozhkov, D. Rozza, G. Rybka, R. Sagdeev, J. Sandwei, P. Saouter, C. Sbarra, S. Schael, S. M. Schmidt, D. Schuckardt, A. S. von, G. Schwering, G. Scolieri, E. S. Seo, B. S. Shan, Y. H. Shan, J. Y. Shi, X. Y. Shi, Y. M. Shi, T. Siedenburg, D. Son, F. Spada, F. Spinella, W. Sun, W. H. Sun, M. Tacconi, C. P. Tang, X. W. Tang, Z. C. Tang, L. Tao, D. Tescaro, S. C. C., S. M. Ting, N. Tomassetti, J. Torsti, C. Turkoglu, T. Urban, V. Vagelli, E. Valente, C. Vannini, E. Valtonen, S. Vaurynovich, M. Vecchi, M. Velasco, J. P. Vialle, V. Vitale, G. Volpini, L. Q. Wang, Q. L. Wang, R. S. Wang, X. Wang, Z. X. Wang, Z. L. Weng, K. Whitman, J. Wienkenhover, H. Wu, K. Y. Wu, X. Xia, M. Xie, S. Xie, R. Q. Xiong, G. M. Xin, N. S. Xu, W. Xu, Q. Yan, J. Yang, M. Yang, Q. H. Ye, H. Yi, Y. J. Yu, Z. Q. Yu, S. Zeissler, J. H. Zhang, M. T. Zhang, X. B. Zhang, Z. Zhang, Z. M. Zheng, F. Zhou, H. L. Zhuang, V. Zhukov, A. Zichichi, N. Zimmermann, P. Zuccon, C. Zurbach, Istituto Nazionale di Fisica Nucleare, Sezione di Perugia (INFN, Sezione di Perugia), Istituto Nazionale di Fisica Nucleare (INFN), Centro de Investigaciones Energéticas Medioambientales y Tecnológicas [Madrid] (CIEMAT), Institut für Experimentelle Kernphysik [Karlsruhe] (EKP), Karlsruher Institut für Technologie (KIT), Jülich Aachen Research Alliance (JARA), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), CERN [Genève], Istituto Nazionale di Fisica Nucleare, Sezione di Roma 3 (INFN, Sezione di Roma 3), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), University of Turku, Massachusetts Institute of Technology (MIT), INFN Sezione di Pisa (INFN Sezione di Pisa), University of Hawai'i [Honolulu] (UH), Istituto Nazionale di Fisica Nucleare, Sezione di Milano (INFN), Karlsruhe Institute of Technology (KIT), NASA Johnson Space Center (JSC), NASA, Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Département de Physique Nucléaire et Corpusculaire [Genève] (DPNC), Université de Genève (UNIGE), Istituto Nazionale di Ottica [Firenze] (INO-CNR), Consiglio Nazionale delle Ricerche (CNR), Istituto Nazionale di Fisica Nucleare [Pisa] (INFN), EWHA Womans University (EWHA), National Central University [Taiwan] (NCU), Academia Sinica, Istituto Nazionale di Fisica Nucleare, Sezione di Bologna (INFN, Sezione di Bologna), Laboratoire Univers et Particules de Montpellier (LUPM), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), and AMS

Subjects
Astrophysics and Astronomy, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Astrophysics::High Energy Astrophysical Phenomena, General Physics and Astronomy, cosmic rays studies, Cosmic ray, Electron, ddc:500.2, 7. Clean energy, Space mission, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Nuclear physics, Physics and Astronomy (all), FIS/05 - ASTRONOMIA E ASTROFISICA, Positron, International Space Station, Alpha Magnetic Spectrometer, ddc:550, Dark matter, ASTROPARTICLE PHYSICS, AMS, Cosmic rays, Positron fraction, antimatter and dark matter, positrons, Physics, Range (particle radiation), ta115, Magnetic spectrometer, ELECTRONS, Cosmic rays, Positron fraction, International Space Station, FIS/01 - FISICA SPERIMENTALE, Physics::Accelerator Physics, Satellite, High Energy Physics::Experiment, Particle Physics - Experiment, Energy (signal processing)
Abstract

A precision measurement by AMS of the positron fraction in primary cosmic rays in the energy range from 0.5 to 500 GeV based on 10.9 million positron and electron events is presented. This measurement extends the energy range of our previous observation and increases its precision. The new results show, for the first time, that above ∼200 GeV the positron fraction no longer exhibits an increase with energy.

Published
2016
Full Text
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12. Precision Measurement of the (e^{+}+e^{-}) Flux in Primary Cosmic Rays from 0.5 GeV to 1 TeV with the Alpha Magnetic Spectrometer on the International Space Station

Author

Aguilar, M., Aisa, D., Alpat, B., Alvino, A., Ambrosi, G., Andeen, K., Arruda, L., Attig, N., Azzarello, P., Bachlechner, A., Barao, F., Barrau, A., Barrin, L., Bartoloni, A., Basara, L., Battarbee, M., Battiston, R., Bazo, J., Becker, U., Behlmann, M., Beischer, B., Berdugo, J., Bertucci, B., Bigongiari, Gabriele, Bindi, V., Bizzaglia, S., Bizzarri, M., Boella, G., De Boer, W., Bollweg, K., Bonnivard, V., Borgia, B., Borsini, S., Boschini, M. J., Bourquin, M., Burger, J., Cadoux, F., Cai, X. D., Capell, M., Caroff, S., Casaus, J., Cascioli, V., Castellini, G., Cernuda, I., Cervelli, F., Chae, M. J., Chang, Y. H., Chen, A. I., Chen, H., Cheng, G. M., Chen, H. S., Cheng, L., Chikanian, A., Chou, H. Y., Choumilov, E., Choutko, V., Chung, C. H., Clark, C., Clavero, R., Coignet, G., Consolandi, C., Contin, A., Corti, C., Coste, B., Crispoltoni, M., Cui, Z., Dai, M., Delgado, C., Della Torre, S., Demirköz, M. B., Derome, L., Di Falco, S., Di Masso, L., Dimiccoli, F., Díaz, C., Von Doetinchem, P., Donnini, F., W. J., Du, Duranti, M., D'Urso, D., Eline, A., Eppling, F. J., Eronen, T., Fan, Y. Y., Farnesini, L., Feng, J., Fiandrini, E., Fiasson, A., Finch, E., Fisher, P., Galaktionov, Y., Gallucci, G., García, B., García López, R., Gargiulo, C., Gast, H., Gebauer, I., Gervasi, M., Ghelfi, A., Gillard, W., Giovacchini, F., Goglov, P., Gong, J., Goy, C., Grabski, V., Grandi, D., Graziani, M., Guandalini, C., Guerri, I., Guo, K. H., Habiby, M., Haino, S., Han, K. C., Z. H., He, Heil, M., Hoffman, J., Hsieh, T. H., Huang, Z. C., Huh, C., Incagli, M., Ionica, M., Jang, W. Y., Jinchi, H., Kanishev, K., Kim, G. N., Kim, K. S., Kirn, T. h., Kossakowski, R., Kounina, O., Kounine, A., Koutsenko, V., Krafczyk, M. S., Kunz, S., La Vacca, G., Laudi, E., Laurenti, G., Lazzizzera, I., Lebedev, A., Lee, H. T., Lee, S. C., Leluc, C., H. L., Li, J. Q., Li, Li, Q., T. X., Li, Li, W., Li, Y., Z. H., Li, Z. Y., Li, Lim, S., Lin, C. H., Lipari, P., Lippert, T., Liu, D., Liu, H., Lomtadze, T., M. J., Lu, Y. S., Lu, Luebelsmeyer, K., Luo, F., Luo, J. Z., S. S., Lv, Majka, R., Malinin, A., Mañá, C., Marín, J., Martin, T., Martínez, G., Masi, N., Maurin, D., Menchaca Rocha, A., Meng, Q., D. C., Mo, Morescalchi, L., Mott, P., Müller, M., J. Q., Ni, Nikonov, N., Nozzoli, F., Nunes, P., Obermeier, A., Oliva, A., Orcinha, M., Palmonari, F., Palomares, C., Paniccia, M., Papi, A., Pauluzzi, M., Pedreschi, E., Pensotti, S., Pereira, R., Pilo, F., Piluso, A., Pizzolotto, C., Plyaskin, V., Pohl, M., Poireau, V., Postaci, E., Putze, A., Quadrani, L., X. M., Qi, Räihä, T., Rancoita, P. G., Rapin, D., Ricol, J. S., Rodríguez, I., Rosier Lees, S., Rozhkov, A., Rozza, D., Sagdeev, R., Sandweiss, J., Saouter, P., Sbarra, C., Schael, S., Schmidt, S. M., Schuckardt, D., Schulz Von Dratzig, A., Schwering, G., Scolieri, G., Seo, E. S., Shan, B. S., Shan, Y. H., Shi, J. Y., Shi, X. Y., Shi, Y. M., Siedenburg, T., Son, D., Spada, F., Spinella, F., Sun, W., Sun, W. H., Tacconi, M., Tang, C. P., Tang, X. W., Tang, Z. C., Tao, L., Tescaro, D., Ting, Samuel C. C., Ting, S. M., Tomassetti, N., Torsti, J., Türkoʇlu, C., Urban, T., Vagelli, V., Valente, E., Vannini, C., Valtonen, E., Vaurynovich, S., Vecchi, M., Velasco, M., Vialle, J. P., Wang, L. Q., Wang, Q. L., Wang, R. S., Wang, X., Wang, Z. X., Weng, Z. L., Whitman, K., Wienkenhöver, J., Wu, H., Xia, X., Xie, M., Xie, S., Xiong, R. Q., Xin, G. M., N. S., Xu, Xu, W., Yan, Q., Yang, J., Yang, M., Q. H., Ye, Yi, H., Y. J., Yu, Z. Q., Yu, Zeissler, S., Zhang, J. H., Zhang, M. T., Zhang, X. B., Zhang, Z., Zheng, Z. M., Zhuang, H. L., Zhukov, V., Zichichi, A., Zimmermann, N., Zuccon, P., Zurbach, C., M. Aguilar, D. Aisa, B. Alpat, A. Alvino, G. Ambrosi, K. Andeen, L. Arruda, N. Attig, P. Azzarello, A. Bachlechner, F. Barao, A. Barrau, L. Barrin, A. Bartoloni, L. Basara, M. Battarbee, R. Battiston, J. Bazo, U. Becker, M. Behlmann, B. Beischer, J. Berdugo, B. Bertucci, G. Bigongiari, V. Bindi, S. Bizzaglia, M. Bizzarri, G. Boella, W. de Boer, K. Bollweg, V. Bonnivard, B. Borgia, S. Borsini, M. J. Boschini, M. Bourquin, J. Burger, F. Cadoux, X. D. Cai, M. Capell, S. Caroff, J. Casau, V. Cascioli, G. Castellini, I. Cernuda, F. Cervelli, M. J. Chae, Y. H. Chang, A. I. Chen, H. Chen, G. M. Cheng, H. S. Chen, L. Cheng, A. Chikanian, H. Y. Chou, E. Choumilov, V. Choutko, C. H. Chung, C. Clark, R. Clavero, G. Coignet, C. Consolandi, A. Contin, C. Corti, B. Coste, M. Crispoltoni, Z. Cui, M. Dai, C. Delgado, S. Della Torre, M. B. Demirköz, L. Derome, S. Di Falco, L. Di Masso, F. Dimiccoli, C. Díaz, P. von Doetinchem, F. Donnini, W. J. Du, M. Duranti, D. D’Urso, A. Eline, F. J. Eppling, T. Eronen, Y. Y. Fan, L. Farnesini, J. Feng, E. Fiandrini, A. Fiasson, E. Finch, P. Fisher, Y. Galaktionov, G. Gallucci, B. García, R. García-López, C. Gargiulo, H. Gast, I. Gebauer, M. Gervasi, A. Ghelfi, W. Gillard, F. Giovacchini, P. Goglov, J. Gong, C. Goy, V. Grabski, D. Grandi, M. Graziani, C. Guandalini, I. Guerri, K. H. Guo, M. Habiby, S. Haino, K. C. Han, Z. H. He, M. Heil, J. Hoffman, T. H. Hsieh, Z. C. Huang, C. Huh, M. Incagli, M. Ionica, W. Y. Jang, H. Jinchi, K. Kanishev, G. N. Kim, K. S. Kim, Th. Kirn, R. Kossakowski, O. Kounina, A. Kounine, V. Koutsenko, M. S. Krafczyk, S. Kunz, G. La Vacca, E. Laudi, G. Laurenti, I. Lazzizzera, A. Lebedev, H. T. Lee, S. C. Lee, C. Leluc, H. L. Li, J. Q. Li, Q. Li, T. X. Li, W. Li, Y. Li, Z. H. Li, Z. Y. Li, S. Lim, C. H. Lin, P. Lipari, T. Lippert, D. Liu, H. Liu, T. Lomtadze, M. J. Lu, Y. S. Lu, K. Luebelsmeyer, F. Luo, J. Z. Luo, S. S. Lv, R. Majka, A. Malinin, C. Mañá, J. Marín, T. Martin, G. Martínez, N. Masi, D. Maurin, A. Menchaca-Rocha, Q. Meng, D. C. Mo, L. Morescalchi, P. Mott, M. Müller, J. Q. Ni, N. Nikonov, F. Nozzoli, P. Nune, A. Obermeier, A. Oliva, M. Orcinha, F. Palmonari, C. Palomare, M. Paniccia, A. Papi, M. Pauluzzi, E. Pedreschi, S. Pensotti, R. Pereira, F. Pilo, A. Piluso, C. Pizzolotto, V. Plyaskin, M. Pohl, V. Poireau, E. Postaci, A. Putze, L. Quadrani, X. M. Qi, T. Räihä, P. G. Rancoita, D. Rapin, J. S. Ricol, I. Rodríguez, S. Rosier-Lee, A. Rozhkov, D. Rozza, R. Sagdeev, J. Sandwei, P. Saouter, C. Sbarra, S. Schael, S. M. Schmidt, D. Schuckardt, A. Schulz von Dratzig, G. Schwering, G. Scolieri, E. S. Seo, B. S. Shan, Y. H. Shan, J. Y. Shi, X. Y. Shi, Y. M. Shi, T. Siedenburg, D. Son, F. Spada, F. Spinella, W. Sun, W. H. Sun, M. Tacconi, C. P. Tang, X. W. Tang, Z. C. Tang, L. Tao, D. Tescaro, Samuel C. C. Ting, S. M. Ting, N. Tomassetti, J. Torsti, C. Türkoğlu, T. Urban, V. Vagelli, E. Valente, C. Vannini, E. Valtonen, S. Vaurynovich, M. Vecchi, M. Velasco, J. P. Vialle, L. Q. Wang, Q. L. Wang, R. S. Wang, X. Wang, Z. X. Wang, Z. L. Weng, K. Whitman, J. Wienkenhöver, H. Wu, X. Xia, M. Xie, S. Xie, R. Q. Xiong, G. M. Xin, N. S. Xu, W. Xu, Q. Yan, J. Yang, M. Yang, Q. H. Ye, H. Yi, Y. J. Yu, Z. Q. Yu, S. Zeissler, J. H. Zhang, M. T. Zhang, X. B. Zhang, Z. Zhang, Z. M. Zheng, H. L. Zhuang, V. Zhukov, A. Zichichi, N. Zimmermann, P. Zuccon, C. Zurbach, Aguilar, M, Aisa, D, Alpat, B, Alvino, A, Ambrosi, G, Andeen, K, Arruda, L, Attig, N, Azzarello, P, Bachlechner, A, Barao, F, Barrau, A, Barrin, L, Bartoloni, A, Basara, L, Battarbee, M, Battiston, R, Bazo, J, Becker, U, Behlmann, M, Beischer, B, Berdugo, J, Bertucci, B, Bigongiari, G, Bindi, V, Bizzaglia, S, Bizzarri, M, Boella, G, de Boer, W, Bollweg, K, Bonnivard, V, Borgia, B, Borsini, S, Boschini, M, Bourquin, M, Burger, J, Cadoux, F, Cai, X, Capell, M, Caroff, S, Casaus, J, Cascioli, V, Castellini, G, Cernuda, I, Cervelli, F, Chae, M, Chang, Y, Chen, A, Chen, H, Cheng, G, Cheng, L, Chikanian, A, Chou, H, Choumilov, E, Choutko, V, Chung, C, Clark, C, Clavero, R, Coignet, G, Consolandi, C, Contin, A, Corti, C, Coste, B, Crispoltoni, M, Cui, Z, Dai, M, Delgado, C, Della Torre, S, Demirköz, M, Derome, L, Di Falco, S, Di Masso, L, Dimiccoli, F, Díaz, C, von Doetinchem, P, Donnini, F, Du, W, Duranti, M, D’Urso, D, Eline, A, Eppling, F, Eronen, T, Fan, Y, Farnesini, L, Feng, J, Fiandrini, E, Fiasson, A, Finch, E, Fisher, P, Galaktionov, Y, Gallucci, G, García, B, García López, R, Gargiulo, C, Gast, H, Gebauer, I, Gervasi, M, Ghelfi, A, Gillard, W, Giovacchini, F, Goglov, P, Gong, J, Goy, C, Grabski, V, Grandi, D, Graziani, M, Guandalini, C, Guerri, I, Guo, K, Habiby, M, Haino, S, Han, K, He, Z, Heil, M, Hoffman, J, Hsieh, T, Huang, Z, Huh, C, Incagli, M, Ionica, M, Jang, W, Jinchi, H, Kanishev, K, Kim, G, Kim, K, Kirn, T, Kossakowski, R, Kounina, O, Kounine, A, Koutsenko, V, Krafczyk, M, Kunz, S, LA VACCA, G, Laudi, E, Laurenti, G, Lazzizzera, I, Lebedev, A, Lee, H, Lee, S, Leluc, C, Li, H, Li, J, Li, Q, Li, T, Li, W, Li, Y, Li, Z, Lim, S, Lin, C, Lipari, P, Lippert, T, Liu, D, Liu, H, Lomtadze, T, Lu, M, Lu, Y, Luebelsmeyer, K, Luo, F, Luo, J, Lv, S, Majka, R, Malinin, A, Mañá, C, Marín, J, Martin, T, Martínez, G, Masi, N, Maurin, D, Menchaca Rocha, A, Meng, Q, Mo, D, Morescalchi, L, Mott, P, Müller, M, Ni, J, Nikonov, N, Nozzoli, F, Nunes, P, Obermeier, A, Oliva, A, Orcinha, M, Palmonari, F, Palomares, C, Paniccia, M, Papi, A, Pauluzzi, M, Pedreschi, E, Pensotti, S, Pereira, R, Pilo, F, Piluso, A, Pizzolotto, C, Plyaskin, V, Pohl, M, Poireau, V, Postaci, E, Putze, A, Quadrani, L, Qi, X, Räihä, T, Rancoita, P, Rapin, D, Ricol, J, Rodríguez, I, Rosier Lees, S, Rozhkov, A, Rozza, D, Sagdeev, R, Sandweiss, J, Saouter, P, Sbarra, C, Schael, S, Schmidt, S, Schuckardt, D, Schulz von Dratzig, A, Schwering, G, Scolieri, G, Seo, E, Shan, B, Shan, Y, Shi, J, Shi, X, Shi, Y, Siedenburg, T, Son, D, Spada, F, Spinella, F, Sun, W, Tacconi, M, Tang, C, Tang, X, Tang, Z, Tao, L, Tescaro, D, Ting, S, Tomassetti, N, Torsti, J, Türkoğlu, C, Urban, T, Vagelli, V, Valente, E, Vannini, C, Valtonen, E, Vaurynovich, S, Vecchi, M, Velasco, M, Vialle, J, Wang, L, Wang, Q, Wang, R, Wang, X, Wang, Z, Weng, Z, Whitman, K, Wienkenhöver, J, Wu, H, Xia, X, Xie, M, Xie, S, Xiong, R, Xin, G, Xu, N, Xu, W, Yan, Q, Yang, J, Yang, M, Ye, Q, Yi, H, Yu, Y, Yu, Z, Zeissler, S, Zhang, J, Zhang, M, Zhang, X, Zhang, Z, Zheng, Z, Zhuang, H, Zhukov, V, Zichichi, A, Zimmermann, N, Zuccon, P, Zurbach, C, Azzarello, Philipp, Bourquin, Maurice, Cadoux, Franck, Habiby Alaoui, Marion, Leluc, Catherine, Li, Yang, Paniccia, Mercedes, Pohl, Martin, Rapin, Divic Jean, and Saouter, Pierre

Subjects
electron, Astrophysics and Astronomy, Astrophysics::High Energy Astrophysical Phenomena, Electrons, ddc:500.2, COSMIC RAYS, AMS, Cosmic Rays, electrons, Space mission, Physics and Astronomy (all), FIS/05 - ASTRONOMIA E ASTROFISICA, Positrons, FIS/01 - FISICA SPERIMENTALE, positron, High Energy Physics::Experiment, AMS, Nuclear Experiment, Particle Physics - Experiment
Abstract

We present a measurement of the cosmic ray (e^+ + e^-) flux in the range 0.5 GeV to 1 TeV based on the analysis of 10.6 million (e^+ + e^-) events collected by AMS. The statistics and the resolution of AMS provide a precision measurement of the flux. The flux is smooth and reveals new and distinct information. Above 30.2 GeV, the flux can be described by a single power law with a spectral index γ = −3.170 +/- 0.008 (stat + syst) +/- 0.008 (energy scale)

Published
2014
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13. Electron and Positron Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station

Author

Aguilar, M, Aisa, D, Alvino, A, Ambrosi, Giovanni, Andeen, K, Arruda, L, Attig, N, Azzarello, P, Bachlechner, A, Barao, F, Barrau, A, Barrin, L, Bartoloni, A, Basara, L, Battarbee, M, Battiston, R, Bazo, J, Becker, U, Behlmann, M, Beischer, B, Berdugo, J, Bertucci, Bruna, Bigongiari, G, Bindi, V, Bizzaglia, S, Bizzarri, M, Boella, G, de Boer, W, Bollweg, K, Bonnivard, V, Borgia, B, Borsini, S, Boschini, Mj, Bourquin, M, Burger, J, Cadoux, F, Cai, Xd, Capell, M, Caroff, S, Casaus, J, Cascioli, V, Castellini, G, Cernuda, I, Cervelli, F, Chae, Mj, Chang, Yh, Chen, Ai, Chen, H, Cheng, Gm, Chen, Hs, Cheng, L, Chikanian, A, Chou, Hy, Choumilov, E, Choutko, V, Chung, Ch, Clark, C, Clavero, R, Coignet, G, Consolandi, C, Contin, A, Corti, C, Coste, B, Cui, Z, Dai, M, Delgado, C, Della Torre, S, Demirköz, Mb, Derome, L, Di Falco, S, Di Masso, L, Dimiccoli, F, Díaz, C, von Doetinchem, P, Du, Wj, Duranti, Matteo, D'Urso, D, Eline, A, Eppling, Fj, Eronen, T, Fan, Yy, Farnesini, L, Feng, J, Fiandrini, Emanuele, Fiasson, A, Finch, E, Fisher, P, Galaktionov, Y, Gallucci, G, García, B, García López, R, Gast, H, Gebauer, I, Gervasi, M, Ghelfi, A, Gillard, W, Giovacchini, F, Goglov, P, Gong, J, Goy, C, Grabski, V, Grandi, D, Graziani, Maura, Guandalini, C, Guerri, I, Guo, Kh, Habiby, M, Haino, S, Han, Kc, He, Zh, Heil, M, Hoffman, J, Hsieh, Th, Huang, Zc, Huh, C, Incagli, M, Ionica, Maria, Jang, Wy, Jinchi, H, Kanishev, K, Kim, Gn, Kim, Ks, Kirn, T, Kossakowski, R, Kounina, O, Kounine, A, Koutsenko, V, Krafczyk, Ms, Kunz, S, La Vacca, G, Laudi, E, Laurenti, G, Lazzizzera, I, Lebedev, A, Lee, Ht, Lee, Sc, Leluc, C, Li, Hl, Li, Jq, Li, Q, Li, Tx, Li, W, Li, Y, Li, Zh, Li, Zy, Lim, S, Lin, Ch, Lipari, P, Lippert, T, Liu, D, Liu, H, Lomtadze, T, Lu, Mj, Lu, Ys, Luebelsmeyer, K, Luo, F, Luo, Jz, Lv, Ss, Majka, R, Malinin, A, Mañá, C, Marín, J, Martin, T, Martínez, G, Masi, N, Maurin, D, Menchaca Rocha, A, Meng, Q, Mo, Dc, Morescalchi, L, Mott, P, Müller, M, Ni, Jq, Nikonov, N, Nozzoli, F, Nunes, P, Obermeier, A, Oliva, A, Orcinha, M, Palmonari, F, Palomares, C, Paniccia, M, Papi, A, Pedreschi, E, Pensotti, S, Pereira, R, Pilo, F, Piluso, A, Pizzolotto, C, Plyaskin, V, Pohl, M, Poireau, V, Postaci, E, Putze, A, Quadrani, L, Qi, Xm, Rancoita, Pg, Rapin, D, Ricol, Js, Rodríguez, I, Rosier Lees, S, Rozhkov, A, Rozza, D, Sagdeev, R, Sandweiss, J, Saouter, P, Sbarra, C, Schael, S, Schmidt, Sm, Schuckardt, D, von Dratzig AS, Schwering, G, Scolieri, G, Seo, Es, Shan, Bs, Shan, Yh, Shi, Jy, Shi, Xy, Shi, Ym, Siedenburg, T, Son, D, Spada, F, Spinella, F, Sun, W, Sun, Wh, Tacconi, M, Tang, Cp, Tang, Xw, Tang, Zc, Tao, L, Tescaro, D, Ting, Sc, Ting, Sm, Tomassetti, Nicola, Torsti, J, Türkoğlu, C, Urban, T, Vagelli, Valerio, Valente, E, Vannini, C, Valtonen, E, Vaurynovich, S, Vecchi, M, Velasco, M, Vialle, Jp, Wang, Lq, Wang, Ql, Wang, Rs, Wang, X, Wang, Zx, Weng, Zl, Whitman, K, Wienkenhöver, J, Wu, H, Xia, X, Xie, M, Xie, S, Xiong, Rq, Xin, Gm, Xu, Ns, Xu, W, Yan, Q, Yang, J, Yang, M, Ye, Qh, Yi, H, Yu, Yj, Yu, Zq, Zeissler, S, Zhang, Jh, Zhang, Mt, Zhang, Xb, Zhang, Z, Zheng, Zm, Zhuang, Hl, Zhukov, V, Zichichi, A, Zimmermann, N, Zuccon, P, Zurbach, C, Pauluzzi, Michele, Azzarello, Philipp, Bourquin, Maurice, Cadoux, Franck, Habiby Alaoui, Marion, Leluc, Catherine, Li, Yang, Paniccia, Mercedes, Pohl, Martin, Rapin, Divic Jean, Saouter, Pierre, Centro de Investigaciones Energéticas Medioambientales y Tecnológicas [Madrid] (CIEMAT), Istituto Nazionale di Fisica Nucleare, Sezione di Perugia (INFN, Sezione di Perugia), Istituto Nazionale di Fisica Nucleare (INFN), Institute of Nanotechnology [Karlsruhe] (INT), Karlsruhe Institute of Technology (KIT), Jülich Aachen Research Alliance (JARA), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), CERN [Genève], Istituto Nazionale di Fisica Nucleare, Sezione di Roma 3 (INFN, Sezione di Roma 3), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), University of Turku, Università degli Studi di Trento (UNITN), Department of Applied Mathematics (MIT), Massachusetts Institute of Technology (MIT), INFN Sezione di Pisa (INFN Sezione di Pisa), University of Hawai'i [Honolulu] (UH), Istituto Nazionale di Fisica Nucleare, Sezione di Milano (INFN), Karlsruher Institut für Technologie (KIT), NASA Johnson Space Center (JSC), NASA, Département de Physique Nucléaire et Corpusculaire [Genève] (DPNC), Université de Genève (UNIGE), CNR Istituto di Geoscienze e Georisorse [Firenze] (IGG), Consiglio Nazionale delle Ricerche (CNR), University of Pisa - Università di Pisa, EWHA Womans University (EWHA), National Central University [Taiwan] (NCU), Institute of High Energy Physics (IHEP), Chinese Academy of Sciences [Changchun Branch] (CAS), Shandong University, Yale University [New Haven], Istituto Nazionale di Fisica Nucleare, Sezione di Bologna (INFN, Sezione di Bologna), Laboratoire Univers et Particules de Montpellier (LUPM), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), AMS, Aguilar, M, Aisa, D, Alvino, A, Ambrosi, G, Andeen, K, Arruda, L, Attig, N, Azzarello, P, Bachlechner, A, Barao, F, Barrau, A, Barrin, L, Bartoloni, A, Basara, L, Battarbee, M, Battiston, R, Bazo, J, Becker, U, Behlmann, M, Beischer, B, Berdugo, J, Bertucci, B, Bigongiari, G, Bindi, V, Bizzaglia, S, Bizzarri, M, Boella, G, de Boer, W, Bollweg, K, Bonnivard, V, Borgia, B, Borsini, S, Boschini, M, Bourquin, M, Burger, J, Cadoux, F, Cai, X, Capell, M, Caroff, S, Casaus, J, Cascioli, V, Castellini, G, Cernuda, I, Cervelli, F, Chae, M, Chang, Y, Chen, A, Chen, H, Cheng, G, Cheng, L, Chikanian, A, Chou, H, Choumilov, E, Choutko, V, Chung, C, Clark, C, Clavero, R, Coignet, G, Consolandi, C, Contin, A, Corti, C, Coste, B, Cui, Z, Dai, M, Delgado, C, Della Torre, S, Demirköz, M, Derome, L, Di Falco, S, Di Masso, L, Dimiccoli, F, Díaz, C, von Doetinchem, P, Du, W, Duranti, M, D’Urso, D, Eline, A, Eppling, F, Eronen, T, Fan, Y, Farnesini, L, Feng, J, Fiandrini, E, Fiasson, A, Finch, E, Fisher, P, Galaktionov, Y, Gallucci, G, García, B, García López, R, Gast, H, Gebauer, I, Gervasi, M, Ghelfi, A, Gillard, W, Giovacchini, F, Goglov, P, Gong, J, Goy, C, Grabski, V, Grandi, D, Graziani, M, Guandalini, C, Guerri, I, Guo, K, Habiby, M, Haino, S, Han, K, He, Z, Heil, M, Hoffman, J, Hsieh, T, Huang, Z, Huh, C, Incagli, M, Ionica, M, Jang, W, Jinchi, H, Kanishev, K, Kim, G, Kim, K, Kirn, T, Kossakowski, R, Kounina, O, Kounine, A, Koutsenko, V, Krafczyk, M, Kunz, S, LA VACCA, G, Laudi, E, Laurenti, G, Lazzizzera, I, Lebedev, A, Lee, H, Lee, S, Leluc, C, Li, H, Li, J, Li, Q, Li, T, Li, W, Li, Y, Li, Z, Lim, S, Lin, C, Lipari, P, Lippert, T, Liu, D, Liu, H, Lomtadze, T, Lu, M, Lu, Y, Luebelsmeyer, K, Luo, F, Luo, J, Lv, S, Majka, R, Malinin, A, Mañá, C, Marín, J, Martin, T, Martínez, G, Masi, N, Maurin, D, Menchaca Rocha, A, Meng, Q, Mo, D, Morescalchi, L, Mott, P, Müller, M, Ni, J, Nikonov, N, Nozzoli, F, Nunes, P, Obermeier, A, Oliva, A, Orcinha, M, Palmonari, F, Palomares, C, Paniccia, M, Papi, A, Pedreschi, E, Pensotti, S, Pereira, R, Pilo, F, Piluso, A, Pizzolotto, C, Plyaskin, V, Pohl, M, Poireau, V, Postaci, E, Putze, A, Quadrani, L, Qi, X, Rancoita, P, Rapin, D, Ricol, J, Rodríguez, I, Rosier Lees, S, Rozhkov, A, Rozza, D, Sagdeev, R, Sandweiss, J, Saouter, P, Sbarra, C, Schael, S, Schmidt, S, Schuckardt, D, von Dratzig, A, Schwering, G, Scolieri, G, Seo, E, Shan, B, Shan, Y, Shi, J, Shi, X, Shi, Y, Siedenburg, T, Son, D, Spada, F, Spinella, F, Sun, W, Tacconi, M, Tang, C, Tang, X, Tang, Z, Tao, L, Tescaro, D, Ting, S, Tomassetti, N, Torsti, J, Türkoğlu, C, Urban, T, Vagelli, V, Valente, E, Vannini, C, Valtonen, E, Vaurynovich, S, Vecchi, M, Velasco, M, Vialle, J, Wang, L, Wang, Q, Wang, R, Wang, X, Wang, Z, Weng, Z, Whitman, K, Wienkenhöver, J, Wu, H, Xia, X, Xie, M, Xie, S, Xiong, R, Xin, G, Xu, N, Xu, W, Yan, Q, Yang, J, Yang, M, Ye, Q, Yi, H, Yu, Y, Yu, Z, Zeissler, S, Zhang, J, Zhang, M, Zhang, X, Zhang, Z, Zheng, Z, Zhuang, H, Zhukov, V, Zichichi, A, Zimmermann, N, Zuccon, P, Zurbach, C, M. Aguilar, D. Aisa, A. Alvino, G. Ambrosi, K. Andeen, L. Arruda, N. Attig, P. Azzarello, A. Bachlechner, F. Barao, A. Barrau, L. Barrin, A. Bartoloni, L. Basara, M. Battarbee, R. Battiston, J. Bazo, U. Becker, M. Behlmann, B. Beischer, J. Berdugo, B. Bertucci, G. Bigongiari, V. Bindi, S. Bizzaglia, M. Bizzarri, G. Boella, W. d. Boer, K. Bollweg, V. Bonnivard, B. Borgia, S. Borsini, M. J. Boschini, M. Bourquin, J. Burger, F. Cadoux, X. D. Cai, M. Capell, S. Caroff, J. Casau, V. Cascioli, G. Castellini, I. Cernuda, F. Cervelli, M. J. Chae, Y. H. Chang, A. I. Chen, H. Chen, G. M. Cheng, H. S. Chen, L. Cheng, A. Chikanian, H. Y. Chou, E. Choumilov, V. Choutko, C. H. Chung, C. Clark, R. Clavero, G. Coignet, C. Consolandi, A. Contin, C. Corti, B. Coste, Z. Cui, M. Dai, C. Delgado, S. D. Torre, M. B. Demirkoz, L. Derome, S. D. Falco, L. D. Masso, F. Dimiccoli, C. Diaz, P. v. Doetinchem, W. J. Du, M. Duranti, D. D'Urso, A. Eline, F. J. Eppling, T. Eronen, Y. Y. Fan, L. Farnesini, J. Feng, E. Fiandrini, A. Fiasson, E. Finch, P. Fisher, Y. Galaktionov, G. Gallucci, B. Garcia, R. Garcia-Lopez, H. Gast, I. Gebauer, M. Gervasi, A. Ghelfi, W. Gillard, F. Giovacchini, P. Goglov, J. Gong, C. Goy, V. Grabski, D. Grandi, M. Graziani, C. Guandalini, I. Guerri, K. H. Guo, M. Habiby, S. Haino, K. C. Han, Z. H. He, M. Heil, J. Hoffman, T. H. Hsieh, Z. C. Huang, C. Huh, M. Incagli, M. Ionica, W. Y. Jang, H. Jinchi, K. Kanishev, G. N. Kim, K. S. Kim, T. Kirn, R. Kossakowski, O. Kounina, A. Kounine, V. Koutsenko, M. S. Krafczyk, S. Kunz, G. L. Vacca, E. Laudi, G. Laurenti, I. Lazzizzera, A. Lebedev, H. T. Lee, S. C. Lee, C. Leluc, H. L. Li, J. Q. Li, Q. Li, T. X. Li, W. Li, Y. Li, Z. H. Li, Z. Y. Li, S. Lim, C. H. Lin, P. Lipari, T. Lippert, D. Liu, H. Liu, T. Lomtadze, M. J. Lu, Y. S. Lu, K. Luebelsmeyer, F. Luo, J. Z. Luo, S. S. Lv, R. Majka, A. Malinin, C. Mana, J. Marin, T. Martin, G. Martinez, N. Masi, D. Maurin, A. Menchaca-Rocha, Q. Meng, D. C. Mo, L. Morescalchi, P. Mott, M. Muller, J. Q. Ni, N. Nikonov, F. Nozzoli, P. Nune, A. Obermeier, A. Oliva, M. Orcinha, F. Palmonari, C. Palomare, M. Paniccia, A. Papi, E. Pedreschi, S. Pensotti, R. Pereira, F. Pilo, A. Piluso, C. Pizzolotto, V. Plyaskin, M. Pohl, V. Poireau, E. Postaci, A. Putze, L. Quadrani, X. M. Qi, P. G. Rancoita, D. Rapin, J. S. Ricol, I. Rodriguez, S. Rosier-Lee, A. Rozhkov, D. Rozza, R. Sagdeev, J. Sandwei, P. Saouter, C. Sbarra, S. Schael, S. M. Schmidt, D. Schuckardt, A. S. von, G. Schwering, G. Scolieri, E. S. Seo, B. S. Shan, Y. H. Shan, J. Y. Shi, X. Y. Shi, Y. M. Shi, T. Siedenburg, D. Son, F. Spada, F. Spinella, W. Sun, W. H. Sun, M. Tacconi, C. P. Tang, X. W. Tang, Z. C. Tang, L. Tao, D. Tescaro, S. C. C., S. M. Ting, N. Tomassetti, J. Torsti, C. Turkoglu, T. Urban, V. Vagelli, E. Valente, C. Vannini, E. Valtonen, S. Vaurynovich, M. Vecchi, M. Velasco, J. P. Vialle, L. Q. Wang, Q. L. Wang, R. S. Wang, X. Wang, Z. X. Wang, Z. L. Weng, K. Whitman, J. Wienkenhover, H. Wu, X. Xia, M. Xie, S. Xie, R. Q. Xiong, G. M. Xin, N. S. Xu, W. Xu, Q. Yan, J. Yang, M. Yang, Q. H. Ye, H. Yi, Y. J. Yu, Z. Q. Yu, S. Zeissler, J. H. Zhang, M. T. Zhang, X. B. Zhang, Z. Zhang, Z. M. Zheng, H. L. Zhuang, V. Zhukov, A. Zichichi, N. Zimmermann, P. Zuccon, and C. Zurbach

Subjects
ASTROPHYSICS, Astrophysics and Astronomy, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Astrophysics::High Energy Astrophysical Phenomena, Positron spectrum, General Physics and Astronomy, Cosmic ray, Electron, ddc:500.2, Space mission, Nuclear physics, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Radiative flux, Physics and Astronomy (all), FIS/05 - ASTRONOMIA E ASTROFISICA, Positron, Alpha Magnetic Spectrometer, ddc:550, Dark matter, Positron emission, AMS, Cosmic rays, electron flux, positron flux, international space station, Cosmic rays, Physics, Spectral index, Range (particle radiation), ta115, POSITRONS, ELECTRONS, FIS/01 - FISICA SPERIMENTALE, High Energy Physics::Experiment, COSMIC RAYS, ELECTRONS, POSITRONS, AMS, Electron spectrum, Astroparticle physics, Astrophysics - High Energy Astrophysical Phenomena, Particle Physics - Experiment
Abstract

International audience; Precision measurements by the Alpha Magnetic Spectrometer on the International Space Station of the primary cosmic-ray electron flux in the range 0.5 to 700 GeV and the positron flux in the range 0.5 to500 GeV are presented. The electron flux and the positron flux each require a description beyond a single power-law spectrum. Both the electron flux and the positron flux change their behavior at∼30GeV but the fluxes are significantly different in their magnitude and energy dependence. Between 20 and 200 GeV the positron spectral index is significantly harder than the electron spectral index. The determination of the differing behavior of the spectral indices versus energy is a new observation and provides important information on the origins of cosmic-ray electrons and positrons.

Published
2014
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