| Paper | Title | Other Keywords | Page |
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| SUPB011 | Computational Model Analysis for Experimental Observation of Optical Current Noise Suppression Below the Shot-noise Limit | plasma, electron, linac, simulation | 25 |
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Funding: We acknowledge support of the Israel Science Foundation grant We report first demonstration of optical frequency current shot-noise suppression in a relativistic e-beam. This process is made possible by collective Coulomb interaction between the electrons of a cold intense beam during beam drift, and is essentially a process of longitudinal beam-plasma oscillation [1]. Suppression of beam current noise below the classical “shot-noise” level has been known in the microwave tubes art [2]. This is the first time that it is demonstrated in the optical regime. We predict that the scheme can be extended to the XUV and possibly to shorter wavelengths with further development of technology. The fundamental current shot-noise determines the level of incoherent spontaneous radiation emission from electron-beam optical radiation sources and SASE-FELs [3]. Suppressing shot-noise would make it possible to attain spontaneous emission sub-radiance [4] and surpass the classical coherence limits of seed-injected FELs. The effect was demonstrated by measuring sub-linear growth as a function of current of the OTR Radiation. This finding indicates that the beam charge homogenizes due to the collective interaction, and its distribution becomes sub-Poissonian. [1] A. Gover, E. Dyunin, PRL, 102, 154801, 2009 [2] H. Haus, N. Robinson, Proc. IRE, 43, 981 (1955) [3] P. Emma, et al , Nature Photonics 4, 641 (2010) [4] A. Dicke, Phys. Rev. 93, 99 (1954) |
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| MOPB096 | Beam Loss Mitigation in J-PARC Linac after the Tohoku Earthquake | linac, multipactoring, beam-losses, radiation | 401 |
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| The beam operation of J-PARC linac was interrupted by the Tohoku earthquake in March 2011. After significant effort for its restoration, we have resumed the beam operation of J-PARC linac in December 2011. After resumption of beam operation, we have been suffering from beam losses which were not observed before the earthquake. Tackling with the beam loss issues, we have been reached the comparable beam power for user operation to the one before the earthquake. In this paper, we present the experience in the beam start-up tuning after the earthquake with emphasis on the beam loss mitigation efforts. | |||
| TUPLB05 | Computational Model Analysis for Experimental Observation of Optical Current Noise Suppression below the Shot-Noise Limit | plasma, electron, linac, simulation | 451 |
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Funding: We acknowledge support of the Israel Science Foundation grant We report first demonstration of optical frequency current shot-noise suppression in a relativistic e-beam. This process is made possible by collective Coulomb interaction between the electrons of a cold intense beam during beam drift, and is essentially a process of longitudinal beam-plasma oscillation [1]. Suppression of beam current noise below the classical “shot-noise” level has been known in the microwave tubes art [2]. This is the first time that it is demonstrated in the optical regime. We predict that the scheme can be extended to the XUV and possibly to shorter wavelengths with further development of technology. The fundamental current shot-noise determines the level of incoherent spontaneous radiation emission from electron-beam optical radiation sources and SASE-FELs [3]. Suppressing shot-noise would make it possible to attain spontaneous emission sub-radiance [4] and surpass the classical coherence limits of seed-injected FELs. The effect was demonstrated by measuring sub-linear growth as a function of current of the OTR Radiation. This finding indicates that the beam charge homogenizes due to the collective interaction, and its distribution becomes sub-Poissonian. [1] A. Gover, E. Dyunin, PRL, 102, 154801, 2009 [2] H. Haus, N. Robinson, Proc. IRE, 43, 981 (1955) [3] P. Emma, et al , Nature Photonics 4, 641 (2010) [4] A. Dicke, Phys. Rev. 93, 99 (1954) |
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| TUPB005 | Computational Model Analysis for Experimental Observation of Optical Current Noise Suppression Below the Shot-noise Limit | plasma, electron, linac, simulation | 482 |
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Funding: We acknowledge support of the Israel Science Foundation grant We report first demonstration of optical frequency current shot-noise suppression in a relativistic e-beam. This process is made possible by collective Coulomb interaction between the electrons of a cold intense beam during beam drift, and is essentially a process of longitudinal beam-plasma oscillation.[1] Suppression of beam current noise below the classical “shot-noise” level has been known in the microwave tubes art [2]. This is the first time that it is demonstrated in the optical regime. We predict that the scheme can be extended to the XUV and possibly to shorter wavelengths with further development of technology. The fundamental current shot-noise determines the level of incoherent spontaneous radiation emission from electron-beam optical radiation sources and SASE-FELs [3]. Suppressing shot-noise would make it possible to attain spontaneous emission sub-radiance [4] and surpass the classical coherence limits of seed-injected FELs. The effect was demonstrated by measuring sub-linear growth as a function of current of the OTR Radiation. This finding indicates that the beam charge homogenizes due to the collective interaction, and its distribution becomes sub-Poissonian. [1] A. Gover, E. Dyunin, PRL, 102, 154801, 2009 [2] H. Haus, N. Robinson, Proc. IRE, 43, 981 (1955) [3] P. Emma, et al , Nature Photonics 4, 641 (2010) [4] A. Dicke, Phys. Rev. 93, 99 (1954) |
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| TH2A004 | Computational Model Analysis for Experimental Observation of Optical Current Noise Suppression Below the Shot-noise Limit | plasma, electron, linac, simulation | 783 |
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Funding: We acknowledge support of the Israel Science Foundation grant We report first demonstration of optical frequency current shot-noise suppression in a relativistic e-beam. This process is made possible by collective Coulomb interaction between the electrons of a cold intense beam during beam drift, and is essentially a process of longitudinal beam-plasma oscillation.[1] Suppression of beam current noise below the classical “shot-noise” level has been known in the microwave tubes art [2]. This is the first time that it is demonstrated in the optical regime. We predict that the scheme can be extended to the XUV and possibly to shorter wavelengths with further development of technology. The fundamental current shot-noise determines the level of incoherent spontaneous radiation emission from electron-beam optical radiation sources and SASE-FELs [3]. Suppressing shot-noise would make it possible to attain spontaneous emission sub-radiance [4] and surpass the classical coherence limits of seed-injected FELs. The effect was demonstrated by measuring sub-linear growth as a function of current of the OTR Radiation. This finding indicates that the beam charge homogenizes due to the collective interaction, and its distribution becomes sub-Poissonian. [1] A. Gover, E. Dyunin, PRL, 102, 154801, 2009 [2] H. Haus, N. Robinson, Proc. IRE, 43, 981 (1955) [3] P. Emma, et al , Nature Photonics 4, 641 (2010) [4] A. Dicke, Phys. Rev. 93, 99 (1954) |
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| THPB021 | Recovery Efforts from the Tohoku Earthquake and Energy Upgrade Preparation of the Beam Transport from the J-PARC Linac to the 3-GeV Synchrotron | linac, radiation, synchrotron, vacuum | 891 |
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| In 2013, the beam energy of the Japan Proton Accelerator Research Complex (J-PARC) linac is going to be increased from 181-MeV to 400-MeV by adding the annular-ring coupled structure (ACS) at the downstream of the 191-MeV drift tube linac. To install and operate all the ACS cavities in only five months of the energy upgrade shutdown in 2013, we decided to replace and upgrade all the related component of the beam line (cables, magnet power supplies and vacuum control systems) for the 400-MeV operation, in the period of the recovery from the Tohoku Earthquake which caused not negligible damage to the J-PARC accelerator facilities. The present beam line is operated by using some part of the 400-MeV componets. In this paper, the recovery of the beam transport, the present status and the future tasks of the beam energy upgrade will be presented. | |||
| THPB051 | Improvements at the BNL 200 MeV Linac | linac, rfq, solenoid, emittance | 969 |
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| After reconfiguration of the low energy (35 keV) and the medium energy (750 keV) transport lines in 2009-10, the Brookhaven linac delivered the highest intensity beam since it was built in 1970 (~120 μA average current of H− to the Brookhaven Linac Isotope Producer). It also delivered lower emittance polarized H− ion beam for the polarized program at RHIC. To increase the intensity further, the match into the RFQ was improved by reducing the distance from the fnal focusing solenoid to the RFQ and replacing the buncher in the 750 keV line with one with higher Q value, to allow operation at higher power. We also found that drift tube linac tank number 7 was operating with about 1 MW lower power than design. The transmission efficiencies and beam quality will be discussed in the paper. | |||