Physical Review Accelerators and Beams最新文献

{"title":"Beam-based commissioning of a novelX-band transverse deflection structure with variable polarization","authors":"P. González Caminalet al.","doi":"10.1103/physrevaccelbeams.27.032801","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.032801","url":null,"abstract":"Longitudinal electron-beam diagnostics play a critical role in the operation and control of x-ray free-electron lasers, which rely on parameters such as the current profile, the longitudinal phase space, or the slice emittance of the particle distribution. On the one hand, the femtosecond-scale electron bunches produced at these facilities impose stringent requirements on the resolution achievable with the diagnostics. On the other, research and development of novel accelerator technologies such as beam-driven plasma-wakefield accelerators (PWFA) demand unprecedented capabilities to resolve the centroid offsets in the full transverse plane along the longitudinal bunch coordinate. We present the beam-based commissioning of an advanced <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>X</mi></math>-band transverse-deflection rf structure (TDS) system with the new feature of providing variable polarization of the deflecting force: the PolariX-TDS. By means of a comprehensive campaign of measurements conducted with the prototype, key parameters of the rf performance of the system are validated and a phase-space characterization of an electron bunch is accomplished with a time resolution of 3.3 fs. Furthermore, an analysis of second-order effects induced on the bunch from its passage through the PolariX-TDS is presented.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"23 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140071252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Terahertz scale microbunching instability driven by high resistivity nonevaporable getter coating resistive-wall impedance","authors":"Weiwei Li, Tianlong He, Zhenghe Bai","doi":"10.1103/physrevaccelbeams.27.034401","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.034401","url":null,"abstract":"Nonevaporable getter (NEG) coating is widely required in the new generation of light sources and circular <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup></math> colliders for small vacuum pipes to improve the vacuum level, which, however, also enhances the high-frequency resistive-wall impedance and often generates a resonator-like peak in the terahertz frequency region. In this paper, we will use the parameters of the planned Hefei Advanced Light Facility storage ring to study the impact of NEG-coating resistive-wall impedance on the longitudinal microwave instability via particle tracking simulation. Using different NEG-coating parameters (resistivity and thickness) as examples, we find that the impedance with a narrow and strong peak in the terahertz frequency region can cause terahertz scale microbunching instability, which has a low instability threshold current and contributes to a large energy spread widening above the threshold. In order to obtain a convergent simulation of the beam dynamics, one must properly resolve such a peak. The coating with a lower resistivity has a less sharp peak in its impedance spectrum, and there is a regime that it is helpful to suppress the terahertz scale microbunching instability and in return contributes to a higher instability threshold current.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"30 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140055891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design concept of aγ-ray beam with low bandwidth and high spectral density","authors":"P. Constantin, C. Matei, C. A. Ur","doi":"10.1103/physrevaccelbeams.27.021601","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.021601","url":null,"abstract":"The Variable Energy Gamma facility of the Extreme Light Infrastructure-Nuclear Physics center will deliver a gamma beam generated by the Compton scattering of laser and electron beams. It will have the highest spectral density and the lowest bandwidth available worldwide. A suite of several experimental setups is being developed for a wide range of research programs in fundamental and applied nuclear science driven by gamma beams. The proposed design concept for this facility is outlined. A study of the gamma beam properties at its source, as well as those after collimation, is presented. The impact of the variation in the parameters of the electron and laser beams on the quality of the gamma beam is analyzed and discussed.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"84 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140007756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards a high-intensity muon source","authors":"Han-Jie Cai, Yuan He, Shuhui Liu, Huan Jia, Yuanshuai Qin, Zhijun Wang, Fengfeng Wang, Lixia Zhao, Neng Pu, Jianwei Niu, Liangwen Chen, Zhiyu Sun, Hongwei Zhao, Wenlong Zhan","doi":"10.1103/physrevaccelbeams.27.023403","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.023403","url":null,"abstract":"A high-intensity muon source driven by a continuous-wave superconducting linac holds the potential to significantly advance the intensity frontier of muon sources. Alongside advancements in accelerator technologies, breakthroughs in muon production target and collection schemes are essential. After a brief introduction to the development of the accelerator-driven system superconducting linac, a novel muon production target is proposed, utilizing a free-surface liquid lithium jet capable of handling the heat power generated by a proton beam with an energy of 600 MeV and a current of 5 mA. It is predicted by our simulation studies that the lithium target is more efficient in surface muon production compared to the rotating graphite target. The parameter space of the front end consisting of a lithium target and a large-aperture capture solenoid is explored, from the perspective of production efficiency, capture efficiency, and characteristics of the surface muon beam.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"8 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140007436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Producing circular field harmonics inside elliptic magnet apertures with superconducting canted-cosine-theta coils","authors":"L. Brouwer","doi":"10.1103/physrevaccelbeams.27.022402","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.022402","url":null,"abstract":"Superconducting magnets with noncircular aperture are desired for accelerators and many other high-field applications. This paper presents new methods for the analytic design of elliptic bore superconducting accelerator magnets. Part 1 of this work shares the derivation of current to field relations between a sheet current density on an elliptic cylinder and the magnetic field harmonics inside the aperture. This result is explored in the general context of elliptic bore magnet design with relevant scaling laws compared between elliptic and circular bore magnets. In part 2, this approach is applied to the specific geometry of canted-cosine-theta (CCT) accelerator magnets, enabling analytic winding design for single or mixed circular harmonics within elliptic aperture CCT magnets.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"23 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140007445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Commissioning of a gantry beamline with rotator at a synchrotron-based ion therapy center","authors":"M. T. F. Pivi, L. Adler, G. Guidoboni, G. Kowarik, C. Kurfürst, C. Maderböck, M. Pavlovič, D. A. Prokopovich, M. G. Pullia, V. Rizzoglio, I. Strašík","doi":"10.1103/physrevaccelbeams.27.023503","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.023503","url":null,"abstract":"This paper provides an overview of the worldwide first commissioning of a gantry beamline with a rotator at the MedAustron synchrotron-based proton/ion cancer therapy facility in Wiener Neustadt, Austria. The gantry beamline consists of the high energy beam transfer (HEBT) line and the gantry beam transport system. It transports the beam from the synchrotron to the gantry-room isocenter. The HEBT transports the beam from the synchrotron to the gantry entrance, which is the coupling point between the HEBT and the gantry. The rotator is one of the HEBT modules, thus it is an integral part of the gantry beamline. The MedAustron rotator is the worldwide first rotator system used to match slowly extracted asymmetric beams from the synchrotron to the rotating gantry. In this paper, main attention is paid to ion-optical and beam-alignment aspects of the beamline commissioning. A novel orbit-correction and beam-alignment technique has been developed specifically for the beamline with the rotator. While the theoretical concept of the rotator has existed for almost two decades, the MedAustron rotator is the first hardware implementation of this concept all over the world. The presented overview of the beamline commissioning includes a description of the principal technical solutions and main results of the first beam-transport measurements. Since the measured beam size and beam position agree well with theoretical predictions, one can conclude that the proof-of-concept of the rotator-matching has been successfully accomplished.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"242 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139967850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High power electrostatic beam splitter for a proton beamline","authors":"M. Hartmann, D. Reggiani, J. Snuverink, H. Zhang, M. Seidel","doi":"10.1103/physrevaccelbeams.27.023502","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.023502","url":null,"abstract":"The High Intensity Proton Accelerator facility (HIPA) delivers a 590 MeV cw (50.6 MHz) proton beam with up to 1.4 MW beam power (2.4 mA) to spallation and meson production targets serving particle physics experiments and material research. The main accelerator is the ring cyclotron, an isochronous proton machine accelerating an injected 72 MeV beam to a final 590 MeV. A few meters downstream of the ring cyclotron, an electrostatic beam splitter was installed in the 1980s and originally designed to peel off from a &lt;math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mrow&gt;&lt;mn&gt;200&lt;/mn&gt;&lt;mtext&gt; &lt;/mtext&gt;&lt;mtext&gt; &lt;/mtext&gt;&lt;mi mathvariant=\"normal\"&gt;μ&lt;/mi&gt;&lt;mi mathvariant=\"normal\"&gt;A&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt; beam up to &lt;math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mrow&gt;&lt;mn&gt;20&lt;/mn&gt;&lt;mtext&gt; &lt;/mtext&gt;&lt;mtext&gt; &lt;/mtext&gt;&lt;mi mathvariant=\"normal\"&gt;μ&lt;/mi&gt;&lt;mi mathvariant=\"normal\"&gt;A&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt; (12 kW beam power). Future initiatives will also make use of the splitter. Specifically, as part of the Isotope and Muon Production using Advanced Cyclotron and Target technologies (IMPACT) upgrade project, Targeted Alpha Tumour Therapy and Other Oncological Solutions (TATTOOS), an online isotope separation facility will allow to produce promising radionuclides for diagnosis and therapy of cancer in quantities sufficient for clinical studies. The TATTOOS facility includes a dedicated beamline intended to operate at a beam intensity of &lt;math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mrow&gt;&lt;mn&gt;100&lt;/mn&gt;&lt;mtext&gt; &lt;/mtext&gt;&lt;mtext&gt; &lt;/mtext&gt;&lt;mi mathvariant=\"normal\"&gt;μ&lt;/mi&gt;&lt;mi mathvariant=\"normal\"&gt;A&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt; (60 kW beam power), requiring continuous splitting of the high-power main beam via the splitter. As a step forward toward reaching the desired beam intensity, a beam study was carried out to test the viability of the existing splitter for TATTOOS. The results of this study show that a record of &lt;math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mrow&gt;&lt;mn&gt;90&lt;/mn&gt;&lt;mtext&gt; &lt;/mtext&gt;&lt;mtext&gt; &lt;/mtext&gt;&lt;mi mathvariant=\"normal\"&gt;μ&lt;/mi&gt;&lt;mi mathvariant=\"normal\"&gt;A&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt; (53 kW beam power) was peeled off a horizontally and vertically enlarged beam by the splitter. The successful beam strategy employed during the study as well as the results of several key measurements are presented in this paper, with particular emphasis on diagnostic measurements. Additionally, to support the measurements, a computational model of the splitter has been implemented using Monte Carlo simulation tools, including realistic geometry, electrostatic fields, beam optics, and power deposition calculations. Overall, the results of this paper show that through the combination of beam measurements and simulations, the existing splitter can be used to reach the &lt;math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mrow&gt;&lt;mn&gt;100&lt;/mn&gt;&lt;mtext&gt;−&lt;/mtext&gt;&lt;mi mathvariant=\"normal\"&gt;μ&lt;/mi&gt;&lt;mi mathvariant=\"normal\"&gt;A&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt; beam intens","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"5 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139927256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mean transverse energy, surface chemical and physical characterization of CERN-made Cs-Te photocathodes","authors":"L. B. Jones, H. Panuganti, C. Benjamin, E. Chevallay, H. M. Churn, V. Fedosseev, T. C. Q. Noakes, L. A. J. Soomary, C. P. Welsch","doi":"10.1103/physrevaccelbeams.27.023402","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.023402","url":null,"abstract":"Cesium telluride photocathodes are known to offer high quantum efficiencies under UV illumination combined with good lifetimes compared to other semiconductor photocathodes, making them very popular electron sources for particle accelerator applications. The development of photocathode preparation, characterization, and related expertise at a single accelerator laboratory can be challenging, expensive, and time consuming. Recognizing this, we explored the use of a custom-designed ultrahigh vacuum suitcase for transportation of CERN-made (Switzerland) cesium telluride photocathodes to Daresbury Laboratory (UK) for characterization. We report the synthesis and characterization of a batch of four cesium telluride photocathodes corresponding to our second attempt of transport, following design and process improvements through lessons learned from our first attempt. The photocathode characterization involved, where possible, measurements of the surface elemental composition using x-ray photoelectron spectroscopy (XPS), surface roughness with an in-vacuum scanning tunneling microscope (STM), and quantum efficiency (QE) measurements. Transverse energy distribution curves were obtained over a wide range of illumination wavelengths using the transverse energy spread spectrometer (TESS) at room- and cryogenic temperatures, and the values for mean transverse energy (MTE) were extracted. The photocathodes exhibited distinct thicknesses ranging from <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo>∼</mo><mn>50</mn></math> to <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo>∼</mo><mn>120</mn><mtext> </mtext><mtext> </mtext><mi>nm</mi></math> and significant MTE beyond the photoemission threshold which is attributed to the presence of <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mrow><mi>Cs</mi></mrow><mrow><mi>x</mi></mrow></msub><mi mathvariant=\"normal\">O</mi></mrow></math> and Cs phases, as confirmed by XPS analysis. The photocathode that exhibited no carbon or oxygen contamination was measured to have the highest QE of 2.9% at a wavelength of 265 nm at the end of the performance characterization process. The results presented herein offer an insight into the achievements possible through international collaborations by successfully utilizing long-distance transportation of photocathodes by land under ultrahigh vacuum conditions.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"4 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139927249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Materials adopted for particle beam windows in relevant experimental facilities","authors":"Lorenzo Notari, Michele Pasquali, Federico Carra, Marcello Losasso, Marilena Tomut","doi":"10.1103/physrevaccelbeams.27.024801","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.024801","url":null,"abstract":"A beam vacuum window is a thin interface of separation between a volume under vacuum and a volume at a higher pressure traversed by particle beams. Their application is not only limited to particle accelerators, where they are typically installed inside the beamline to separate vacuum sectors, but also extends to other fields of nuclear research and to high-power hadron beam applications, such as spallation neutron sources and accelerator-driven systems. The main issue concerning the beam window technology resides intrinsically in the dual role of these components: the thickness of the window is supposed to be as thin as possible to allow the passage of the particles through matter with minimal interaction but, at the same time, enough resistant to maintain the required differential pressure between the two environments.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"9 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139756377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Scattering of high-energy positively charged particles in ultrashort oriented silicon crystal","authors":"S. N. Shulga, I. V. Kyryllin, N. F. Shul’ga","doi":"10.1103/physrevaccelbeams.27.024002","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.024002","url":null,"abstract":"In this work, the process of scattering of high-energy positively charged particles in the field of atomic planes of an ultrashort silicon crystal was studied. In the parabolic potential approximation of atomic planes, analytical expressions are found for the dependence of the coordinates and velocities of particles in a crystal on time and initial conditions. The relationship between the particle incidence angle on the crystal and its deflection angle has also been determined. It is shown that, under certain conditions, a beam can be split by an ultrashort crystal into two beams diverging at an angle equal to twice the angle of planar channeling.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"193 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139763027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}