Pub Date : 2015-08-19DOI: 10.1103/PHYSREVSTAB.18.083501
N. Cherkashyna, D. Dijulio, T. Panzner, E. Rantsiou, U. Filges, G. Ehlers, P. Bentley
The shielding at an accelerator-driven spallation neutron facility plays a critical role in the performance of the neutron scattering instruments, the overall safety, and the total cost of the facility. Accurate simulation of shielding components is thus key for the design of upcoming facilities, such as the European Spallation Source (ESS), currently in construction in Lund, Sweden. In this paper, we present a comparative study between the measured and the simulated neutron background at the Swiss Spallation Neutron Source (SINQ), at the Paul Scherrer Institute (PSI), Villigen, Switzerland. The measurements were carried out at several positions along the SINQ monolith wall with the neutron dosimeter WENDI-2, which has a well-characterized response up to 5 GeV. The simulations were performed using the Monte-Carlo radiation transport code Geant4, and include a complete transport from the proton beam to the measurement locations in a single calculation. An agreement between measurements and simulations is about a factor of 2 for the points where the measured radiation dose is above the background level, which is a satisfactory result for such simulations spanning many energy regimes, different physics processes and transport through several meters of shielding materials. The neutrons contributing to the radiation field emanating from the monolith were confirmed to originate from neutrons with energies above 1 MeV in the target region. The current work validates Geant4 as being well suited for deep-shielding calculations at accelerator-based spallation sources. We also extrapolate what the simulated flux levels might imply for short (several tens of meters) instruments at ESS.
{"title":"Benchmarking shielding simulations for an accelerator-driven spallation neutron source","authors":"N. Cherkashyna, D. Dijulio, T. Panzner, E. Rantsiou, U. Filges, G. Ehlers, P. Bentley","doi":"10.1103/PHYSREVSTAB.18.083501","DOIUrl":"https://doi.org/10.1103/PHYSREVSTAB.18.083501","url":null,"abstract":"The shielding at an accelerator-driven spallation neutron facility plays a critical role in the performance of the neutron scattering instruments, the overall safety, and the total cost of the facility. Accurate simulation of shielding components is thus key for the design of upcoming facilities, such as the European Spallation Source (ESS), currently in construction in Lund, Sweden. In this paper, we present a comparative study between the measured and the simulated neutron background at the Swiss Spallation Neutron Source (SINQ), at the Paul Scherrer Institute (PSI), Villigen, Switzerland. The measurements were carried out at several positions along the SINQ monolith wall with the neutron dosimeter WENDI-2, which has a well-characterized response up to 5 GeV. The simulations were performed using the Monte-Carlo radiation transport code Geant4, and include a complete transport from the proton beam to the measurement locations in a single calculation. An agreement between measurements and simulations is about a factor of 2 for the points where the measured radiation dose is above the background level, which is a satisfactory result for such simulations spanning many energy regimes, different physics processes and transport through several meters of shielding materials. The neutrons contributing to the radiation field emanating from the monolith were confirmed to originate from neutrons with energies above 1 MeV in the target region. The current work validates Geant4 as being well suited for deep-shielding calculations at accelerator-based spallation sources. We also extrapolate what the simulated flux levels might imply for short (several tens of meters) instruments at ESS.","PeriodicalId":20072,"journal":{"name":"Physical Review Special Topics-accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87502737","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}
Pub Date : 2015-08-19DOI: 10.1103/PHYSREVSTAB.18.080101
C. A. Valerio-Lizarraga, I. Leon-Monzon, R. Scrivens
The space charge of intense unbunched ion beams can be compensated by the ions created when the beam ionizes the residual gas, which creates a source of secondary particles inside the beam pipe. For negative ion beams, the effect of the beam electric field is to expel the electrons to the beam pipe walls, while the positive ions are trapped and start to be accumulated. In this paper, we report on experiments to study this space charge compensation (SCC) in a 45 keV ${mathrm{H}}^{ensuremath{-}}$ unbunched beam in the CERN Linac4 low-energy beam transport. Beam size and emittance were measured for different gases injected into the beam region to control the degree and speed of the SCC. These results are compared with beam simulations that include the generation and tracking of secondary ions leading to a unique understanding of the transport of the ion beam in some specific cases.
{"title":"Negative ion beam space charge compensation by residual gas","authors":"C. A. Valerio-Lizarraga, I. Leon-Monzon, R. Scrivens","doi":"10.1103/PHYSREVSTAB.18.080101","DOIUrl":"https://doi.org/10.1103/PHYSREVSTAB.18.080101","url":null,"abstract":"The space charge of intense unbunched ion beams can be compensated by the ions created when the beam ionizes the residual gas, which creates a source of secondary particles inside the beam pipe. For negative ion beams, the effect of the beam electric field is to expel the electrons to the beam pipe walls, while the positive ions are trapped and start to be accumulated. In this paper, we report on experiments to study this space charge compensation (SCC) in a 45 keV ${mathrm{H}}^{ensuremath{-}}$ unbunched beam in the CERN Linac4 low-energy beam transport. Beam size and emittance were measured for different gases injected into the beam region to control the degree and speed of the SCC. These results are compared with beam simulations that include the generation and tracking of secondary ions leading to a unique understanding of the transport of the ion beam in some specific cases.","PeriodicalId":20072,"journal":{"name":"Physical Review Special Topics-accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75099186","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}
Pub Date : 2015-08-19DOI: 10.1103/PHYSREVSTAB.18.083401
A. Bartnik, C. Gulliford, I. Bazarov, Luca Cultera, B. Dunham
Characterization of 9--9.5 MeV electron beams produced in the dc-gun based Cornell photoinjector is given for bunch charges ranging from 20 pC to 2 nC. Comparison of the measured emittances and longitudinal current profiles to optimized 3D space charge simulations yields excellent agreement for bunch charges up to 1 nC when the measured laser distribution is used to generate initial particle distributions in simulation. Analysis of the scaling of the measured emittance with bunch charge shows that the emittance scales roughly as the square root of the bunch charge up to 300 pC, above which the trend becomes linear. These measurements demonstrate that the Cornell photoinjector can produce cathode emittance dominated beams meeting the emittance and peak current specifications for next generation free electron lasers operating at high repetition rate. In addition, the 1 and 2 nC results are relevant to the electron ion collider community.
{"title":"Operational experience with nanocoulomb bunch charges in the Cornell photoinjector","authors":"A. Bartnik, C. Gulliford, I. Bazarov, Luca Cultera, B. Dunham","doi":"10.1103/PHYSREVSTAB.18.083401","DOIUrl":"https://doi.org/10.1103/PHYSREVSTAB.18.083401","url":null,"abstract":"Characterization of 9--9.5 MeV electron beams produced in the dc-gun based Cornell photoinjector is given for bunch charges ranging from 20 pC to 2 nC. Comparison of the measured emittances and longitudinal current profiles to optimized 3D space charge simulations yields excellent agreement for bunch charges up to 1 nC when the measured laser distribution is used to generate initial particle distributions in simulation. Analysis of the scaling of the measured emittance with bunch charge shows that the emittance scales roughly as the square root of the bunch charge up to 300 pC, above which the trend becomes linear. These measurements demonstrate that the Cornell photoinjector can produce cathode emittance dominated beams meeting the emittance and peak current specifications for next generation free electron lasers operating at high repetition rate. In addition, the 1 and 2 nC results are relevant to the electron ion collider community.","PeriodicalId":20072,"journal":{"name":"Physical Review Special Topics-accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73107314","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}
Pub Date : 2015-08-17DOI: 10.1103/PHYSREVSTAB.18.082801
A. Uchiyama, Kazuro Furukawa
Remote operation and diagnostic systems for particle accelerators have been developed for beam operation and maintenance in various situations. Even though fully remote experiments are not necessary, the remote diagnosis and maintenance of the accelerator is required. Considering remote-operation operator interfaces (OPIs), the use of standard protocols such as the hypertext transfer protocol (HTTP) is advantageous, because system-dependent protocols are unnecessary between the remote client and the onsite server. Here, we have developed a client system based onWebSocket, which is a new protocol provided by the Internet Engineering Task Force for Web-based systems, as a next-generation Web-based OPI using the Experimental Physics and Industrial Control System Channel Access protocol. As a result of this implementation, WebSocket-based client systems have become available for remote operation. Also, as regards practical application, the remote operation of an accelerator via a wide area network (WAN) faces a number of challenges, e.g., the accelerator has both experimental device and radiation generator characteristics. Any error in remote control system operation could result in an immediate breakdown. Therefore, we propose the implementation of an operator intervention system for remote accelerator diagnostics and support that can obviate any differences between the local control room and remote locations. Here, remote-operation Web-based OPIs, which resolve security issues, are developed.
{"title":"Development of wide area environment accelerator operation and diagnostics method","authors":"A. Uchiyama, Kazuro Furukawa","doi":"10.1103/PHYSREVSTAB.18.082801","DOIUrl":"https://doi.org/10.1103/PHYSREVSTAB.18.082801","url":null,"abstract":"Remote operation and diagnostic systems for particle accelerators have been developed for beam operation and maintenance in various situations. Even though fully remote experiments are not necessary, the remote diagnosis and maintenance of the accelerator is required. Considering remote-operation operator interfaces (OPIs), the use of standard protocols such as the hypertext transfer protocol (HTTP) is advantageous, because system-dependent protocols are unnecessary between the remote client and the onsite server. Here, we have developed a client system based onWebSocket, which is a new protocol provided by the Internet Engineering Task Force for Web-based systems, as a next-generation Web-based OPI using the Experimental Physics and Industrial Control System Channel Access protocol. As a result of this implementation, WebSocket-based client systems have become available for remote operation. Also, as regards practical application, the remote operation of an accelerator via a wide area network (WAN) faces a number of challenges, e.g., the accelerator has both experimental device and radiation generator characteristics. Any error in remote control system operation could result in an immediate breakdown. Therefore, we propose the implementation of an operator intervention system for remote accelerator diagnostics and support that can obviate any differences between the local control room and remote locations. Here, remote-operation Web-based OPIs, which resolve security issues, are developed.","PeriodicalId":20072,"journal":{"name":"Physical Review Special Topics-accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81480804","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}
Pub Date : 2015-08-06DOI: 10.1103/PHYSREVSTAB.18.081302
M. Kasim, J. Holloway, L. Ceurvorst, M. C. Levy, N. Ratan, J. Sadler, R. Bingham, P. Burrows, R. Trines, M. Wing, P. Norreys
Diagnosing plasma conditions can give great advantages in optimizing plasma wakefield accelerator experiments. One possible method is that of photon acceleration. By propagating a laser probe pulse through a plasma wakefield and extracting the imposed frequency modulation, one can obtain an image of the density modulation of the wakefield. In order to diagnose the wakefield parameters at a chosen point in the plasma, the probe pulse crosses the plasma at oblique angles relative to the wakefield. In this paper, mathematical expressions relating the frequency modulation of the laser pulse and the wakefield density profile of the plasma for oblique crossing angles are derived. Multidimensional particle-in-cell simulation results presented in this paper confirm that the frequency modulation profiles and the density modulation profiles agree to within 10%. Limitations to the accuracy of the measurement are discussed in this paper. This technique opens new possibilities to quantitatively diagnose the plasma wakefield density at known positions within the plasma column.
{"title":"Quantitative single shot and spatially resolved plasma wakefield diagnostics","authors":"M. Kasim, J. Holloway, L. Ceurvorst, M. C. Levy, N. Ratan, J. Sadler, R. Bingham, P. Burrows, R. Trines, M. Wing, P. Norreys","doi":"10.1103/PHYSREVSTAB.18.081302","DOIUrl":"https://doi.org/10.1103/PHYSREVSTAB.18.081302","url":null,"abstract":"Diagnosing plasma conditions can give great advantages in optimizing plasma wakefield accelerator experiments. One possible method is that of photon acceleration. By propagating a laser probe pulse through a plasma wakefield and extracting the imposed frequency modulation, one can obtain an image of the density modulation of the wakefield. In order to diagnose the wakefield parameters at a chosen point in the plasma, the probe pulse crosses the plasma at oblique angles relative to the wakefield. In this paper, mathematical expressions relating the frequency modulation of the laser pulse and the wakefield density profile of the plasma for oblique crossing angles are derived. Multidimensional particle-in-cell simulation results presented in this paper confirm that the frequency modulation profiles and the density modulation profiles agree to within 10%. Limitations to the accuracy of the measurement are discussed in this paper. This technique opens new possibilities to quantitatively diagnose the plasma wakefield density at known positions within the plasma column.","PeriodicalId":20072,"journal":{"name":"Physical Review Special Topics-accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91013706","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}
Pub Date : 2015-08-05DOI: 10.1103/PHYSREVSTAB.18.081001
I. Strašík, I. Prokhorov, O. Boine-Frankenheim
This paper presents a systematic study of the halo collimation of ion beams from proton up to uranium in synchrotrons. The projected Facility for Antiproton and Ion Research synchrotron SIS100 is used as a reference case. The concepts are separated into fully stripped (e.g., 238 U 92þ ) and partially stripped (e.g., 238 U 28þ ) ion collimation. An application of the two-stage betatron collimation system, well established for proton accelerators, is intended also for fully stripped ions. The two-stage system consists of a primary collimator (a scattering foil) and secondary collimators (bulky absorbers). Interaction of the particles with the primary collimator (scattering, momentum losses, and nuclear interactions) was simulated by using FLUKA. Particle-tracking simulations were performed by using MAD-X. Finally, the dependence of the collimation efficiency on the primary ion species was determined. The influence of the collimation system adjustment, lattice imperfections, and beam parameters was estimated. The concept for the collimation of partially stripped ions employs a thin stripping foil in order to change their charge state. These ions are subsequently deflected towards a dump location using a beam optical element. The charge state distribution after the stripping foil was obtained from GLOBAL. The ions were tracked by using MAD–X.
本文系统地研究了同步加速器中质子至铀离子束的晕准直。以计划中的反质子和离子研究同步加速器SIS100为参考案例。这些概念被分为完全剥离(例如，238 U 92þ)和部分剥离(例如，238 U 28þ)离子准直。两级质子加速器准直系统的应用，建立了质子加速器，也打算完全剥离离子。两级系统由主准直器(散射箔)和次准直器(大体积吸收器)组成。利用FLUKA模拟了粒子与主准直器的相互作用(散射、动量损失和核相互作用)。利用MAD-X进行粒子跟踪模拟。最后，确定了准直效率与主离子种类的关系。估计了准直系统调整、点阵缺陷和光束参数的影响。部分剥离离子的准直概念采用薄剥离箔来改变它们的电荷状态。这些离子随后使用光束光学元件向倾倒位置偏转。用GLOBAL得到了剥离箔后的电荷态分布。离子被用MAD-X跟踪。
{"title":"Beam halo collimation in heavy ion synchrotrons","authors":"I. Strašík, I. Prokhorov, O. Boine-Frankenheim","doi":"10.1103/PHYSREVSTAB.18.081001","DOIUrl":"https://doi.org/10.1103/PHYSREVSTAB.18.081001","url":null,"abstract":"This paper presents a systematic study of the halo collimation of ion beams from proton up to uranium in synchrotrons. The projected Facility for Antiproton and Ion Research synchrotron SIS100 is used as a reference case. The concepts are separated into fully stripped (e.g., 238 U 92þ ) and partially stripped (e.g., 238 U 28þ ) ion collimation. An application of the two-stage betatron collimation system, well established for proton accelerators, is intended also for fully stripped ions. The two-stage system consists of a primary collimator (a scattering foil) and secondary collimators (bulky absorbers). Interaction of the particles with the primary collimator (scattering, momentum losses, and nuclear interactions) was simulated by using FLUKA. Particle-tracking simulations were performed by using MAD-X. Finally, the dependence of the collimation efficiency on the primary ion species was determined. The influence of the collimation system adjustment, lattice imperfections, and beam parameters was estimated. The concept for the collimation of partially stripped ions employs a thin stripping foil in order to change their charge state. These ions are subsequently deflected towards a dump location using a beam optical element. The charge state distribution after the stripping foil was obtained from GLOBAL. The ions were tracked by using MAD–X.","PeriodicalId":20072,"journal":{"name":"Physical Review Special Topics-accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78070926","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}
Pub Date : 2015-07-22DOI: 10.1103/PHYSREVSTAB.18.074401
A. Macridin, A. Burov, E. Stern, J. Amundson, P. Spentzouris
Transverse dipole modes in bunches with space charge are simulated using the synergia accelerator modeling package and analyzed with dynamic mode decomposition. The properties of the first three space charge modes, including their shape, damping rates, and tune shifts are described over the entire range of space charge strength. The intrinsic Landau damping predicted and estimated in 2009 by one of the authors is confirmed with a reasonable scaling factor of $ensuremath{simeq}2.4$. For the KV distribution, very good agreement with PATRIC simulations performed by Kornilov and Boine-Frankenheim is obtained.
{"title":"Simulation of transverse modes with their intrinsic Landau damping for bunched beams in the presence of space charge","authors":"A. Macridin, A. Burov, E. Stern, J. Amundson, P. Spentzouris","doi":"10.1103/PHYSREVSTAB.18.074401","DOIUrl":"https://doi.org/10.1103/PHYSREVSTAB.18.074401","url":null,"abstract":"Transverse dipole modes in bunches with space charge are simulated using the synergia accelerator modeling package and analyzed with dynamic mode decomposition. The properties of the first three space charge modes, including their shape, damping rates, and tune shifts are described over the entire range of space charge strength. The intrinsic Landau damping predicted and estimated in 2009 by one of the authors is confirmed with a reasonable scaling factor of $ensuremath{simeq}2.4$. For the KV distribution, very good agreement with PATRIC simulations performed by Kornilov and Boine-Frankenheim is obtained.","PeriodicalId":20072,"journal":{"name":"Physical Review Special Topics-accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81041002","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}
Pub Date : 2015-07-22DOI: 10.1103/PHYSREVSTAB.18.074004
R. Talman, J. Talman
There has been much recent interest in directly measuring the electric dipole moments (EDM) of the proton and the electron. Such a measurement will require storing a polarized beam of "frozen spin" particles in an all-electric storage ring. Only one such relativistic electric accelerator has ever been built---the "Electron Analogue" ring at Brookhaven National Laboratory in 1954. By chance this electron ring, long since dismantled, would have been appropriate both for measuring the electron EDM and to serve as an inexpensive prototype for the arguably more promising, but ten times more expensive, proton EDM measurement. Today it is cheaper yet to "resurrect" the Electron Analogue ring by simulating its performance computationally. This is one purpose for the present paper. To set up these calculations has required a kind of "archeological physics" to reconstitute the detailed Electron Analogue lattice design. The new UAL/ETEAPOT code, described in detail in an accompanying paper, has been developed for modeling storage ring performance, including (exact BMT) spin evolution, in electric rings. Illustrating its use, comparing its predictions with the old observations, and describing new expectations concerning spin evolution and code performance, are other goals of the paper. This paper describes the practical application of the ETEAPOT code and provides sample results, with emphasis on emulating lattice optics in the AGS Analogue ring for comparison with the historical maching studies and to predict the electron spin evolution they would have measured. To exhibit the ETEAPOT code performance and confirm its symplecticity, results are also given for 30 million turn proton spin tracking in an all-electric lattice that would be appropriate for a present day measurement of the proton EDM.
{"title":"Electric dipole moment planning with a resurrected BNL Alternating Gradient Synchrotron electron analog ring","authors":"R. Talman, J. Talman","doi":"10.1103/PHYSREVSTAB.18.074004","DOIUrl":"https://doi.org/10.1103/PHYSREVSTAB.18.074004","url":null,"abstract":"There has been much recent interest in directly measuring the electric dipole moments (EDM) of the proton and the electron. Such a measurement will require storing a polarized beam of \"frozen spin\" particles in an all-electric storage ring. Only one such relativistic electric accelerator has ever been built---the \"Electron Analogue\" ring at Brookhaven National Laboratory in 1954. By chance this electron ring, long since dismantled, would have been appropriate both for measuring the electron EDM and to serve as an inexpensive prototype for the arguably more promising, but ten times more expensive, proton EDM measurement. \u0000Today it is cheaper yet to \"resurrect\" the Electron Analogue ring by simulating its performance computationally. This is one purpose for the present paper. To set up these calculations has required a kind of \"archeological physics\" to reconstitute the detailed Electron Analogue lattice design. The new UAL/ETEAPOT code, described in detail in an accompanying paper, has been developed for modeling storage ring performance, including (exact BMT) spin evolution, in electric rings. Illustrating its use, comparing its predictions with the old observations, and describing new expectations concerning spin evolution and code performance, are other goals of the paper. \u0000This paper describes the practical application of the ETEAPOT code and provides sample results, with emphasis on emulating lattice optics in the AGS Analogue ring for comparison with the historical maching studies and to predict the electron spin evolution they would have measured. To exhibit the ETEAPOT code performance and confirm its symplecticity, results are also given for 30 million turn proton spin tracking in an all-electric lattice that would be appropriate for a present day measurement of the proton EDM.","PeriodicalId":20072,"journal":{"name":"Physical Review Special Topics-accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91184727","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}
Pub Date : 2015-07-13DOI: 10.1103/PhysRevSTAB.18.123401
V. Mironov, S. Bogomolov, A. Bondarchenko, A. Efremov, V. Loginov
Important features of Electron Cyclotron Resonance Ion Source (ECRIS) operation are accurately reproduced with a numerical code. The code uses the particle-in-cell technique to model a dynamics of ions in ECRIS plasma. It is shown that gas dynamical ion confinement mechanism is sufficient to provide the ion production rates in ECRIS close to the experimentally observed values. Extracted ion currents are calculated and compared to the experiment for few sources. Changes in the extracted ion currents are obtained with varying the gas flow into the source chamber and the microwave power. Empirical scaling laws for ECRIS design are studied and the underlying physical effects are discussed.
{"title":"Numerical model of Electron Cyclotron Resonance Ion Source","authors":"V. Mironov, S. Bogomolov, A. Bondarchenko, A. Efremov, V. Loginov","doi":"10.1103/PhysRevSTAB.18.123401","DOIUrl":"https://doi.org/10.1103/PhysRevSTAB.18.123401","url":null,"abstract":"Important features of Electron Cyclotron Resonance Ion Source (ECRIS) operation are accurately reproduced with a numerical code. The code uses the particle-in-cell technique to model a dynamics of ions in ECRIS plasma. It is shown that gas dynamical ion confinement mechanism is sufficient to provide the ion production rates in ECRIS close to the experimentally observed values. Extracted ion currents are calculated and compared to the experiment for few sources. Changes in the extracted ion currents are obtained with varying the gas flow into the source chamber and the microwave power. Empirical scaling laws for ECRIS design are studied and the underlying physical effects are discussed.","PeriodicalId":20072,"journal":{"name":"Physical Review Special Topics-accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74992810","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}
Pub Date : 2015-07-10DOI: 10.1103/PHYSREVSTAB.18.071304
D. Margarone, I. J. Kim, J. Psikal, J. Kaufman, T. Mocek, I. Choi, L. Štolcová, J. Proska, A. Choukourov, I. Melnichuk, O. Klimo, J. Limpouch, J. Sung, S. Lee, G. Korn, T. Jeong
A high-energy, high-yield proton beam with a good homogeneous profile has been generated from a nanosphere target irradiated by a short (30-fs), intense ($7ifmmodetimeselsetexttimesfi{}{10}^{20}text{ }text{ }mathrm{W}/{mathrm{cm}}^{2}$) laser pulse. A maximum proton energy of 30 MeV has been observed with a high proton number of $7ifmmodetimeselsetexttimesfi{}{10}^{10}$ in the energy range 5--30 MeV. A homogeneous spatial profile with a uniformity (standard deviation from an average value within 85% beam area) of 15% is observed with the nanosphere dielectric target. Particle-in-cell simulations show the enhancement of proton cutoff energy and proton number with the nanosphere target and reveal that the homogeneous beam profile is related with a broadened angular distribution of hot electrons, which is initiated by the nanosphere structure. The homogeneous spatial properties obtained with the nanosphere target will be advantageous in developing laser-driven proton sources for practical applications in which high-quality beams are required.
{"title":"Laser-driven high-energy proton beam with homogeneous spatial profile from a nanosphere target","authors":"D. Margarone, I. J. Kim, J. Psikal, J. Kaufman, T. Mocek, I. Choi, L. Štolcová, J. Proska, A. Choukourov, I. Melnichuk, O. Klimo, J. Limpouch, J. Sung, S. Lee, G. Korn, T. Jeong","doi":"10.1103/PHYSREVSTAB.18.071304","DOIUrl":"https://doi.org/10.1103/PHYSREVSTAB.18.071304","url":null,"abstract":"A high-energy, high-yield proton beam with a good homogeneous profile has been generated from a nanosphere target irradiated by a short (30-fs), intense ($7ifmmodetimeselsetexttimesfi{}{10}^{20}text{ }text{ }mathrm{W}/{mathrm{cm}}^{2}$) laser pulse. A maximum proton energy of 30 MeV has been observed with a high proton number of $7ifmmodetimeselsetexttimesfi{}{10}^{10}$ in the energy range 5--30 MeV. A homogeneous spatial profile with a uniformity (standard deviation from an average value within 85% beam area) of 15% is observed with the nanosphere dielectric target. Particle-in-cell simulations show the enhancement of proton cutoff energy and proton number with the nanosphere target and reveal that the homogeneous beam profile is related with a broadened angular distribution of hot electrons, which is initiated by the nanosphere structure. The homogeneous spatial properties obtained with the nanosphere target will be advantageous in developing laser-driven proton sources for practical applications in which high-quality beams are required.","PeriodicalId":20072,"journal":{"name":"Physical Review Special Topics-accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80940829","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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