Su-in Jeon, Heetae Kim, Yoochul Jung, Juwan Kim, Junwoo Lee, M. Kim, Hyunik Kim, Sangbeen Lee, Minki Lee
Performance of superconducting cavities are investigated with field emission effect and x-ray detection. Conducting particles and surface curvature can cause field emission from the surface of the superconducting Nb cavity. The field emission makes the local temperature increase, the surface resistance increase, and then the quality factor decrease. Vertical test is performed for half-wave resonator (HWR) cavities. The vertical test facilities are introduced and the quality factors are measured for the half-wave resonator (HWR) cavities. The quality factors of the cavities decrease as the x-ray are increased. The surface resistance and x-ray generation of the cavity can be fitted well with the field emission theory. The quality factors for the half-wave resonator (HWR) cavities decrease linearly with the field enhancement factor for x-ray generation.
{"title":"Field Emission and X-Ray Effect on Half-Wave Resonator (HWR) Superconducting Cavity Performance","authors":"Su-in Jeon, Heetae Kim, Yoochul Jung, Juwan Kim, Junwoo Lee, M. Kim, Hyunik Kim, Sangbeen Lee, Minki Lee","doi":"10.2139/ssrn.3944526","DOIUrl":"https://doi.org/10.2139/ssrn.3944526","url":null,"abstract":"Performance of superconducting cavities are investigated with field emission effect and x-ray detection. Conducting particles and surface curvature can cause field emission from the surface of the superconducting Nb cavity. The field emission makes the local temperature increase, the surface resistance increase, and then the quality factor decrease. Vertical test is performed for half-wave resonator (HWR) cavities. The vertical test facilities are introduced and the quality factors are measured for the half-wave resonator (HWR) cavities. The quality factors of the cavities decrease as the x-ray are increased. The surface resistance and x-ray generation of the cavity can be fitted well with the field emission theory. The quality factors for the half-wave resonator (HWR) cavities decrease linearly with the field enhancement factor for x-ray generation.","PeriodicalId":375434,"journal":{"name":"PhysicsRN EM Feeds","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127522661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiao Chen, Liangjin Huang, Hua Yang, Xiaoming Xi, Yi An, Zhiping Yan, Yi-sha Chen, Z. Pan, P. Zhou
In this paper, we have theoretically and experimentally demonstrated a novel large-mode-area multi-resonant all-solid photonic bandgap fiber (AS-PBGF). Based on the combination of the multi-resonant structure and leakage channel, the structural parameters are specifically designed for conventional applications of fiber lasers around 1 μm wavelength. Through the stack and draw technique, the fiber is fabricated successfully and the hexagon core is measured to be 46 μm in the corner-to-corner direction. The transmission spectrum exhibits a broad bandwidth from 970 nm to 1180 nm in the 3rd photonic bandgap (PBG). Bending loss lower than 0.1 dB/m with a 5-m-length fiber is obtained in the case of bending radius R > 25 cm. By employing the spatially and spectrally resolved imaging (S2) method, robust single-mode (SM) operation of the fiber is verified within the whole PBG. In addition, we also report a phenomenon about the abnormal variation of M2 within the low loss region of the 3rd PBG. The evolution of beam quality within the 3rd PBG appears as a U-shaped curve rather than a constant. Based on the measured M2 and S2 results, a preliminary conclusion about the relationship between the beam quality and SM characteristics in AS-PBGF, which is quite different from that in conventional SIFs, is demonstrated experimentally for the first time.
{"title":"Large-Mode-Area Multi-Resonant All-Solid Photonic Bandgap Fiber with Low Bending Loss and Robust Single-Mode Operation","authors":"Xiao Chen, Liangjin Huang, Hua Yang, Xiaoming Xi, Yi An, Zhiping Yan, Yi-sha Chen, Z. Pan, P. Zhou","doi":"10.2139/ssrn.3944527","DOIUrl":"https://doi.org/10.2139/ssrn.3944527","url":null,"abstract":"In this paper, we have theoretically and experimentally demonstrated a novel large-mode-area multi-resonant all-solid photonic bandgap fiber (AS-PBGF). Based on the combination of the multi-resonant structure and leakage channel, the structural parameters are specifically designed for conventional applications of fiber lasers around 1 μm wavelength. Through the stack and draw technique, the fiber is fabricated successfully and the hexagon core is measured to be 46 μm in the corner-to-corner direction. The transmission spectrum exhibits a broad bandwidth from 970 nm to 1180 nm in the 3rd photonic bandgap (PBG). Bending loss lower than 0.1 dB/m with a 5-m-length fiber is obtained in the case of bending radius R > 25 cm. By employing the spatially and spectrally resolved imaging (S2) method, robust single-mode (SM) operation of the fiber is verified within the whole PBG. In addition, we also report a phenomenon about the abnormal variation of M2 within the low loss region of the 3rd PBG. The evolution of beam quality within the 3rd PBG appears as a U-shaped curve rather than a constant. Based on the measured M2 and S2 results, a preliminary conclusion about the relationship between the beam quality and SM characteristics in AS-PBGF, which is quite different from that in conventional SIFs, is demonstrated experimentally for the first time.","PeriodicalId":375434,"journal":{"name":"PhysicsRN EM Feeds","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130488515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Unlike in the traditional punishment mechanism, punishers driven by inequity aversion punish individuals who have a higher payoff, rather than those who adopt a certain strategy, and the intensity of punishment varies with payoff difference. This paper studies the impact of this special punishment on cooperation. We obtain phase diagrams by studying the stationary state of the three-strategy system with cooperators, inequity-averse individuals and defectors under different parameters in a structured population. In addition, we observe spatial dynamics to explore the underlying mechanisms of some phases and phase transitions. The results indicate that inequity aversion driven punishment can promote cooperation due to a high-intensity punishment and network reciprocity. However, the unnecessary loss caused by the punishment on cooperators or even other inequity-averse punishers can reduce the efficiency in promoting cooperation. Although cooperators are sometimes punished, as second-order free-riders, they still have an adverse impact on the propagation of cooperation, by inhibiting the expansion of inequity-averse individuals in the interface separating three strategies for a high punishment cost coefficient, and indirectly compete for territory with inequity-averse individuals for a high synergy factor.
{"title":"The Effect of Inequity Aversion Driven Punishment on Cooperation","authors":"Xianjia Wang, Rui Ding, Jinhuan Zhao, Wenman Chen, Cuiling Gu","doi":"10.2139/ssrn.3996845","DOIUrl":"https://doi.org/10.2139/ssrn.3996845","url":null,"abstract":"Unlike in the traditional punishment mechanism, punishers driven by inequity aversion punish individuals who have a higher payoff, rather than those who adopt a certain strategy, and the intensity of punishment varies with payoff difference. This paper studies the impact of this special punishment on cooperation. We obtain phase diagrams by studying the stationary state of the three-strategy system with cooperators, inequity-averse individuals and defectors under different parameters in a structured population. In addition, we observe spatial dynamics to explore the underlying mechanisms of some phases and phase transitions. The results indicate that inequity aversion driven punishment can promote cooperation due to a high-intensity punishment and network reciprocity. However, the unnecessary loss caused by the punishment on cooperators or even other inequity-averse punishers can reduce the efficiency in promoting cooperation. Although cooperators are sometimes punished, as second-order free-riders, they still have an adverse impact on the propagation of cooperation, by inhibiting the expansion of inequity-averse individuals in the interface separating three strategies for a high punishment cost coefficient, and indirectly compete for territory with inequity-averse individuals for a high synergy factor.","PeriodicalId":375434,"journal":{"name":"PhysicsRN EM Feeds","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115526119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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