{"title":"Dielectric Disk Accelerator for High Gradient Short Pulse Two-Beam Wakefield Acceleration","authors":"C. Jing, J. Shao, J. Power, M. Conde, S. Doran","doi":"10.1109/AAC.2018.8659397","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659397","url":null,"abstract":"In the last two decades, the theoretical and experimental investigations of dielectric accelerating structures for application to wakefield acceleration have predominantly used a dielectric-lined waveguide, due to its simple geometry (i.e. low fabrication cost). However, in comparison with the prevailing metallic disk-loaded accelerators, the dielectric-lined waveguide suffers from a lower Q-factor and lower shunt impedance. We are developing a new dielectric disk accelerator. The preliminary simulation shows that, even with 5×10−4 of loss tangent dielectric material $(E_{r}=50)$, we can achieve ~200 MΩ/m shunt impedance at 26 GHz traveling wave operation (the beam aperture is kept the same in the comparison), which is 4 times higher than those of the conventional dielectric loaded accelerator. The dielectric disk accelerator can overcome conventional limitations on high gradient, high efficiency dielectric accelerator, leading to a breakthrough in the performance of the two-beam accelerator, one of the most promising technologies in the category of advanced accelerator concepts for high energy physics research applications.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"142 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114999012","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}
I. Pagano, Jason Brooks, A. Bernstein, R. Zgadzaj, J. Leddy, J. Cary, M. Downer
{"title":"Low Density Plasma Waveguides Driven by Ultrashort (30 fs) and Long (300 ps) Pulses for Laser Wakefield Acceleration","authors":"I. Pagano, Jason Brooks, A. Bernstein, R. Zgadzaj, J. Leddy, J. Cary, M. Downer","doi":"10.1109/AAC.2018.8659410","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659410","url":null,"abstract":"We simulate the possibility of scaling channel formation to low densities plasmas of low atomic number gas over a large range of pulse duration including (1) pulses up to 300 ps in duration, using inverse bremsstrahlung (IB) heating and (2) ultrashort pulses up to 100s of femtoseconds for generating tenuous plasmas of centimeter to meter lengths by optical field ionization (OFI) [1]. Results show IB heating up to tens of eV, and channels formed from an initial density of 1×10<sup>18</sup> cm<sup>−3</sup> with axial densities as low as 1×10<sup>17</sup> cm<sup>−3</sup>, and radius of 50 μm. It has been shown that centimeter-scale waveguides can be generated via OFI heating at densities of approximately 1×10<sup>17</sup> cm<sup>−3</sup>[2]; we show calculations and theory of this channel formation using an axicon. Lastly, we outline the experimental setup to be used in future experiments at the University of Texas Tabletop Terawatt (UT3) facility.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122016372","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}
{"title":"Generating Quasi-Single Multi - Terawatt Picosecond Pulses in the Neptune CO2 Laser System","authors":"E. Welch, D. Matteo, S. Tochitsky, C. Joshi","doi":"10.1109/AAC.2018.8659412","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659412","url":null,"abstract":"We discuss the status of the University of California, Los Angeles Neptune Laboratory CO2 master oscillator-power amplifier (MOPA) system and recent modifications aimed to obtain quasi-single pulses with 5–10 TW in the leading 3 ps pulse. A new optical parametric amplification front end capable of produclng ≤ 10 μJ in a few picosecond long, 10 μm pulse was tested experimentally. By switching the regenerative preamplifier in the MOPA to a multipass configuration, the nanosecond contrast is expected to improve by a factor of 103.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126821155","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}
{"title":"Summary of Working Group 3: Laser and High-Gradient Structure-Based Acceleration","authors":"P. Musumeci, A. Grassellino","doi":"10.1109/AAC.2018.8659434","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659434","url":null,"abstract":"High-gradient particle acceleration with reduced power demands is essential for miniaturization and cost reduction of future accelerators. Working Group 3 discussed and surveyed the recent advances in achieving higher gradients and better acceleration efficiency in externally powered, structure-based accelerators. The working group was organized as a survey of the different schemes and the relevant associated techniques and structures as a function of frequency, all the way from radiofrequency (RF) bands to infrared and visible lasers. Other relevant topics such as power sources or electron beam sources peculiar of a given frequency range were also discussed. Further details on each of these topics can be found in the respective papers in these Proceedings.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126308009","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}
{"title":"Preface: 18th Advanced Accelerator Concepts Workshop (AAC 2018)","authors":"E. Simakov, N. Yampolsky, K. Wootton","doi":"10.1109/AAC.2018.8659389","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659389","url":null,"abstract":"The Eighteenth Workshop on Advanced Accelerator Concepts (AAC 2018) was held at the Beaver Run Resort and Conference Center in Breckenridge, Colorado, USA on August 12–17, 2018. This paper prefaces a set of 67 conference proceedings published by the presenters and attendees of the Workshop and summarizes the proceedings and the Workshop.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133975040","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}
O. Zarini, A. Köhler, J. Couperus, R. Pausch, T. Kurz, S. Schöbel, Heide Meissner, M. Bussmann, U. Schramm, A. Irman, A. Debus
{"title":"Advanced Methods for Temporal Reconstruction of Modulated Electron Bunches","authors":"O. Zarini, A. Köhler, J. Couperus, R. Pausch, T. Kurz, S. Schöbel, Heide Meissner, M. Bussmann, U. Schramm, A. Irman, A. Debus","doi":"10.1109/AAC.2018.8659388","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659388","url":null,"abstract":"We describe optimizations of phase-retrieval algorithms for the reconstruction of the temporal structure of highly modulated electron bunches from coherent transition radiation (CTR) spectra. Synthetic data is used to quantitatively analyze capabilities and limitations of the approach taking into account realistic bandwidth constraints of ultra-broadband spectrometers. Established algorithms are combined with information from independent channels as charge calibrated electron spectra and absolute intensity calibration of the spectrometer. With this set of data, in principle available in experiments, we demonstrate a promising fidelity for the detailed analysis of substructured laser wakefield accelerated electron bunches.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"92 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131579623","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}
{"title":"Preparation for an Emittance Exchange Based Bunch compression Experiment at Argonne Wakefield Accelerator Facility","authors":"J. Seok, G. Ha, J. Power, M. Conde, M. Chung","doi":"10.1109/AAC.2018.8659409","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659409","url":null,"abstract":"The emittance exchange (EEX) is a recently developed beam manipulation method providing the longitudinal bunch compression. Since EEX converts the transverse phase space to the longitudinal phase space, it can generate a sub-fs bunch when a small bunch gets appropriate transverse focusing. Argonne Wakefield Accelerator facility (AWA) plans to demonstrate this EEX based sub-fs generation for the high frequency wakefield acceleration. The primary experiment is planned in this summer to explore the minimum achievable bunch length of current configuration. The result will indicate what upgrades we need to experimentally generate a sub-fs bunch. We present progress on the simulation work for this summer experiment and modified EEX beamline generating the sub-fs bunch as an example.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131059809","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}
T. Mehrling, C. Benedetti, C. Schroeder, E. Esarey
{"title":"A Subgrid Algorithm for the Efficient Modeling of Plasma-Based Accelerators with Ion Motion Using Quasi-Static Particle-in-Cell Codes","authors":"T. Mehrling, C. Benedetti, C. Schroeder, E. Esarey","doi":"10.1109/AAC.2018.8659404","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659404","url":null,"abstract":"Ion motion has a strong impact on the quality preservation of electron beams in plasma-based colliders. While being crucial for the advance of plasma-based accelerators, the modeling of the physics of interest is highly challenging due to the large disparity of the relevant transverse length scales. To correctly model plasma-based collider schemes with ion motion, a high transverse resolution must be employed in particle-in-cell simulations, which, conventionally, entails significant computational costs. By introducing a refined subgrid in the witness beam region in a quasi-static particle-in-cell code, significant computational savings can be achieved. This numerical approach allows for the accurate modeling of plasma-based colliders with ion motion in the blowout regime while allowing for an orders of maznitude computational speedup.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132447652","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}
W. Kuropka, R. Abmann, F. Burkart, H. Cankaya, U. Dorda, I. Hartl, F. Kärtner, F. Lemery, B. Marchetti, F. Mayet
{"title":"Plans for Dielectric Laser Accelerators at SINBAD","authors":"W. Kuropka, R. Abmann, F. Burkart, H. Cankaya, U. Dorda, I. Hartl, F. Kärtner, F. Lemery, B. Marchetti, F. Mayet","doi":"10.1109/AAC.2018.8659395","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659395","url":null,"abstract":"Short and INnovative Bunches and Accelerators At Desy (SINBAD) at Deutsches Elektronen Synchrotron (DESY) is a dedicated long-term accelerator development and research facility. It is foreseen to house several research efforts towards novel high gradient particle acceleration technologies including THz, plasma and dielectric laser based types. A brief overview will be provided. Among the candidates for future applications are dielectric laser accelerators (DLA). Within the Accelerator on a CHip International program (ACHIP) collaboration funded by Gordon and Betty Moore Foundation, grating type DLAs are being investigated with the goal to build a 1 MeV ‘shoe box’ table top accelerator, only requiring a suitable laser system as input. To achieve this goal, the creation and handling of micro-bunch trains in the regime suitable for DLA has to be researched. The Accelerator Research Experiment at SINBAD (ARES) linear accelerator will to deliver very low-emittance, ultra-short, high-quality electron bunches to be used to investigate these topics. Two experimental approaches towards these goals are presented. One is focused on producing and injecting a phase-synchronous micro-bunch train into a DLA. This experiment is suitable for controlling the phase between electron bunches and the accelerating fields comparable to conventional radiofrequency accelerators. A micro-bunching scheme from seeded free-electron-laser applications using a laser modulator and a magnetic chicane is foreseen to be implemented. The laser for the modulator will also drive the DLA, connecting the spacing in the micro-bunch to the periodicity of the accelerator. An additional approach is focused towards injection of a fs electron bunch into a DLA, probing the accelerating fields and showing different spectra of the particles correlated to the injection phase. The general limitations will be also be discussed. First experiments are planned for spring 2019.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128865329","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}
{"title":"Longitudinal Beam-Shaping Simulation for Enhanced Transformer Ratio in Beam-Driven Accelerators","authors":"W. Tan, P. Piot, A. Zholents","doi":"10.1109/AAC.2018.8659429","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659429","url":null,"abstract":"A beam-driven structure wakefield accelerator (SWFA) is currently under consideration for future multi-user xray free-electron-laser (FEL) light sources. One of the challenges associated with SWFA is the efficient energy transfer from the drive to the main bunch that can be enhanced via a precise control over the drive-bunch current profile. This paper discusses the development and initial beam-dynamics simulation of the drive-bunch longitudinal dynamics using the fast-tracking program TWICE. This code, written in PYTHON, allows for rapid prototyping of the beam shaping process while taking into account the collective effects using simplified models. This paper describes the algorithm implementation and its capabilities of including collective effects into both forward and backward tracking. Initial results of optimizing beam shape with a conventional linac to produce a drive beam with a shape optimized for SFWA are presented.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130904757","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}