| Accelerator Physics and Technology Seminar/td> |
| Regular seminars are held Tuesday, 4:00 pm in Wilson Hall, 1-West.
During spring/summer, seminars are also offered on Thursday. Special dates and rooms are announced below. |
| Back to latest schedule |
Tuesday, February 19, 2019 at 4:00 pm
Speaker: Vitaly Yakimenko, SLAC
Title: Collider of Fields : On the Prospect of Studying Fully Non-Perturbative QED with Beam-Beam Collisions
Abstract:
The talk will discuss how modern accelerator technology can probe a fundamentally different regime of physics – fully Non-Perturbative QED – for the first time. The key idea is to employ compressed bunches that are shorter than the average photon emission length to probe unprecedented extreme field strengths, which facilitate fully Non-Perturbative QED experiments with a 100 GeV-class particle collider. In addition, it also has multiple important implications for different areas of physics. For example, this approach to the mitigation of radiative energy losses (“beamstrahlung”), which is a critical limitation of existing linear collider designs like ILC and CLIC, represents an opportunity to reduce the power consumption of these machines significantly. The Energy frontier in electron/positron particle physics could then reach energies prohibited by the beam power requirement in conventional collisions of flat bunches.Tuesday, March 5, 2019 at 4:00 pm
Speaker: Alexey Burov, FNAL
Title: Transverse Convective Instabilities of a Bunched Beam with Strong Space Charge
Abstract:
Although the space charge typically suppresses the transverse mode-coupling instability (TMCI), it does not mean that it stabilizes the beam. Suppressing TMCI, the space charge brings in a whole family of convective instabilities for the same beam and machine parameters. This new sort of instabilities will be introduced and generally described. They explain tail-dominating oscillations and weak dependence of the transverse stability threshold on space charge, observed at CERN SPS.Monday, March 11, 2019 at 4:00 pm
Speaker: Andrei Seryi, JLAB
Title: JLEIC Electron-Ion Collider Advances and Opportunities
Abstract:
A U.S.-based Electron-Ion Collider (EIC) has recently been endorsed by the U.S. National Academies of Sciences, Engineering, and Medicine (NAS). This brings the realization of such a collider another step closer, after its earlier recommendation in the 2015 Long-Range Plan for U.S. nuclear science of the Nuclear Science Advisory Committee ``as the highest priority for new facility construction following the completion of FRIB''. An EIC will be an unprecedented collider that will need to maintain high luminosity (1E33-1E34 cm-2 s-1) over a very wide range of Center-of- Mass energies (~20 GeV to ~100 GeV, upgradable to ~140 GeV), while accommodating highly polarized beams and many different ion species. A multi-laboratory collaboration is presently working on two site-specific EIC designs - eRHIC led by BNL and JLEIC led by Jefferson Lab. The JLEIC design maximally leverages the existing CEBAF capability for production of polarized electron beams, and leverages the innovative figure-8 rings to achieve high luminosity and high values of beam polarization for protons, deuterons and other ions. The present talk will summarize the status of JLEIC Electron Ion Collider design and R&D.Thursday, March 21, 2019 at 4:00 pm
Speaker: Yong Liu, KEK
Title: Progress of J-PARC LINAC Commissioning
Abstract:
After linac energy and intensity upgrade to 400MeV and 50mA respectively, J-PARC linac were ready for equivalent 1 MW beam power from RCS in 2014. The next milestones 1.2 and 1.5MW from RCS are relying on feasibility and property of increase of peak current to 60 mA and the pulse width to 600us in linac. Beam studies were carried out at linac to study the initial beam parameters from ion source/RFQ, to find the optimized lattice and matching, to clarify beam loss source and to mitigate the loss/residue dose for the power upgrade.Tuesday, March 26, 2019 at 4:00 pm
Speaker: Jeff Eldred, FNAL
Title: Rapid-Cycling Synchrotron for Multi-Megawatt Proton Facility at Fermilab
Abstract:
A new Rapid-Cycling Synchotron (RCS) has long been proposed as an option to enable multi-MW beam power at the Main Injector. The DUNE Interim Design Report calls for a 2.4 MW upgrade to Fermilab proton complex by 2032. Most RCS-based scenarios to achieve this objective are really two-fold -- replacing the Booster with a new RCS while simultaneously upgrading the PIP-II linac energy to 2 GeV. Instead, we pursue a staged approach - first, achieving the 2.4 MW benchmark with an RCS-only stage; second, preparing to take full advantage of any follow-up upgrade to linac energy. We will highlight several notable features of our RCS and discuss the wider implications for the proton complex. The RCS extraction energy is raised to 11 GeV to improve high-power performance of the Main Injector. And instead of using the Fermilab Recycler, slip-stacking would return to the Main Injector. The RCS facility would also provide a new 11 GeV beamline with 400 kW beam power, potentially upgradeable to over a 1 MW. We would like a encourage feedback from variety of perspectives on the future of the Fermilab proton facility.Thursday, April 4, 2019 at 3:30 pm
Speaker: Guglielmo Scovazzi, Duke University
Title: Numerical simulations in complex geometry: from imaging to computing without CAD
Abstract:
In applications such as subsurface/geomechanical sciences, additive manufacturing, advanced prototyping,or biomedical sciences, imaging techniques are now providing an unprecedented level of resolution. As an inevitable consequence, the level of geometric complexity of the shapes obtained with imaging/computer-graphics techniques is posing severe challenges toCAD tools. We present an alternative approach to the numericalsimulationof problems involving complexgeometry, in which the CAD geometry generation is bypassed in favor of a new breed of immersed/embedded boundary methods of finite element type.Embedded boundary methods obviate the need for continual re-meshing in many applications involving rapid prototyping and/or complex design. Unfortunately, many embedded boundary methods are difficult to implement due to the need to perform complex cell cutting operations at boundaries, and the consequences that these operations may have on the overall condition number of the ensuing algebraic problems.We present a new, stable, and simple embedded boundary method, the shifted boundary method (SBM), which eliminates the need to perform cell cutting. Boundary conditions are imposed on a surrogate discrete boundary, lying on the interior of the true boundary interface. We then construct appropriate field extension operators, with the purpose of preserving accuracy when imposing the boundary conditions. The SBM method is proved to be stable and convergent for the Poisson and linear advection diffusion problems. We further demonstrate the SBM on large-scale incompressible flow problems, multiphase flow problems, solid mechanics problems, and complex flow in porous media.Tuesday, April 16, 2019 at 4:00 pm
Speaker: Felicie Albert, Lawerence Livermore National Laboratory
Title: X-ray sources from laser-plasma acceleration: development and applications for high energy density sciences
Abstract:
Bright sources of x-rays, such as synchrotrons and x-ray free electron lasers (XFEL) are transformational tools for many fields of science. They are used for biology, material science, medicine, or industry. Such sources rely on conventional particle accelerators, where electrons are accelerated to gigaelectronvolts (GeV) energies. The accelerating particles are also wiggled in magnetic structures to emit x-ray radiation that is commonly used for molecular crystallography, fluorescence studies, chemical analysis, medical imaging, and many other applications. One of the drawbacks of synchrotrons and XFELs is their size and cost, because electric field gradients are limited to about a few 10s of MeV/M in conventional accelerators. This seminar will review particle acceleration in laser-driven plasmas as an alternative to generate x-rays. A plasma is an ionized medium that can sustain electrical fields many orders of magnitude higher than that in conventional radiofrequency accelerator structures. When short, intense laser pulses are focused into a gas, it produces electron plasma waves in which electrons can be trapped and accelerated to GeV energies. This process, laser-wakefield acceleration (LWFA), is analogous to a surfer being propelled by an ocean wave. Betatron x-ray radiation, driven by electrons from laser-wakefield acceleration, has unique properties that are analogous to synchrotron radiation, with a 1000-fold shorter pulse. This source is produced when relativistic electrons oscillate during the LWFA process. An important use of x-rays from laser plasma accelerators we will discuss is in High Energy Density (HED) science. This field uses large laser and x-ray free electron laser facilities to create in the laboratory extreme conditions of temperatures and pressures that are usually found in the interiors of stars and planets. To diagnose such extreme states of matter, the development of efficient, versatile and fast (sub-picosecond scale) x-ray probes has become essential. In these experiments, x-ray photons can pass through dense material, and absorption of the x-rays can be directly measured, via spectroscopy or imaging, to inform scientists about the temperature and density of the targets being studied.Thursday, April 18, 2019 at 4:00 pm
Speaker: Professor Yannis K. Semertzidis, Korea Advanced Inst. of Science and Technology (KAIST)
Title: A hybrid ring to probe the proton EDM down to 10^-29 e-cm and beyond: a strict test of CP-violation in QCD
Abstract:
Hadronic electric dipole moment experiments (EDM) probe CP-violating phases from New Physics and also from the so-called theta_QCD with highest sensitivity than any other EDM experiments. Storage ring EDM methods provide a new opportunity in terms of improving the statistical and systematic errors in the quest of a more sensitive EDM probe. The all-electric and the hybrid (electric bending with magnetic focusing) rings allow for simultaneous clock-wise and counter-clock-wise storage, enabling us to effectively deal with the major systematic error sources.Tuesday, April 30, 2019 at 4:00 pm
Speaker: Jean-Luc Vay, LBNL
Title: High-performance computer modeling of conventional and advanced-concept particle accelerators
Abstract:
The LBNL's Accelerator Modeling Program (AMP) develops the mathematical models, algorithms and codes for the study of the physics of the generation, acceleration, propagation and manipulation of charged particle beams. It manages and provides the Berkeley Lab Accelerator Simulation Toolkit (BLAST), a set of high-performance parallel codes for the modeling of conventional and advanced-concept particle accelerators. We will present the latest developments in mathematical models and algorithms, code developments and implementations on the latest computing architectures, as well as applications to existing or planned particle accelerator projects. We will also discuss our plans toward the modeling of extreme particle beams.Thursday, May 02, 2019 at 4:00 pm
Speaker: Grigory Eremeev, JLAB
Title: Progress in Nb3Sn SRF cavity research at Jefferson Lab
Abstract:
Jefferson Lab SRF institute is a part of a global efforts to advance superconducting RF technology for accelerator applications. A host to superconducting CEBAF accelerator, JLab plays a role in current SRF projects worldwide, such as ILC, LCLS-II, LHC-HL, etc. Since 2012 JLab has an active R&D program on Nb3Sn coatings for accelerator applications. Starting with R&D single-cell development, we are working to implement the best Nb3Sn coatings onto practical accelerator cavities towards cryomodule integration. In my presentation I will give a short overview of the current state-of-the-art, discuss the opportunities with Nb3Sn, and present our status and progress in Nb3Sn development over the past several years.Tuesday, May 07, 2019 at 4:00 pm
Speaker: Diktys Stratakis, FNAL
Title: Commissioning and First Results of the Fermilab Muon Campus
Abstract:
In the following years, the Fermilab Muon Campus will deliver highly polarized muon beams to the Muon g-2 Experiment. The Muon Campus contains a target section wherein secondaries are produced, the delivery ring which separates the muons from the rest of the beam and a sequence of beamlines that transports them to the Muon g-2 storage ring. Here, we report the first results of beam measurements at the Muon Campus with emphasis on the key achievements that have contributed to the successful beam delivery to the Muon g-2 Experiment. These achievements include the production of an intense secondary beam from the target, it's transport over 2 km, the successful monitoring of muons from the available diagnostics and the development of techniques for measuring the transverse optics. We also present detailed comparisons between experimental data and simulation and discuss the similarities and differences observed.Friday, May 10, 2019 at 2:00 pm
Speaker: Timofey Zolkin, FNAL
Title: Isolated Period Three Implies Chaos
Abstract:
The Sharkovskii's theorem about chaos in1D discrete dynamical systems is considered. We suggest a generalization to 2D symplectic mappings with analytic invariant of motion. Some ideas on further generalization are discussed.Thursday, May 23, 2019 at 1:00 pm
Speaker: Panagiotis Baxevanis, SLAC
Title:Theory of microbunched electron cooling (MBEC)
Abstract:
The technique of michrobunched electron cooling (MBEC) [1] is an attractive scheme for enhancing the brightness of stored hadron beams in future high-energy circular colliders, which is a crucial requirement for achieving the luminosities necessary for experiments. In MBEC, the hadron beam imprints an energy modulation on a co-propagating electron beam, which is converted into a density modulation after passage through a chicane. The bunched e-beam then interacts with the hadrons once more in a subsequent section of the machine, in a way that can ultimately lead to a significant reduction in the hadron energy spread and emittance. In this talk, we present a one-dimensional theory of this method that covers the cooling mechanism for both the longitudinal and the transverse degrees of freedom. Using a kinetic theory approach, we derive relatively simple analytical expressions for the cooling times in terms of the various beam and lattice parameters, allowing us to perform fast optimization and tolerance studies. Verified through comparison with 1D simulation, our theory also incorporates important features such as plasma amplification stages for the electron beam, which aim to drastically reduce the cooling time in a realistic machine configuration. [1] D. Ratner. Phys. Rev. Lett. 111, 084802 (2013).Wednesday, May 30, 2019 at 3:00 pm
Speaker: Daniel Ratner, SLAC
Title:Machine Learning for an X-ray Laser
Abstract:
Machine learning (ML) has surged in popularity in the last decade, driven by impressive results in everything from medicine to self-driving cars to playing the game of Go. Accelerator physicists, who have used ML methods for decades with varying degrees of success, are now able to take advantage of these industrial advances. In the last few years SLAC has begun to see substantial improvements in performance from ML methods. I will give three examples of recent work at SLAC: Bayesian optimization of an x-ray laser, reconstruction of ultrafast x-ray fields with neural networks, and in-the-loop experimental control with reinforcement learning.Tuesday, June 4, 2019 at 4:00 pm
Speaker: Alexander Shemyakin, FNAL
Title:Measurements of a 2.1-MeV H- beam with an Allison scanner
Abstract:
A prototype of the PIP-II linac front end called PIP-II Injector Test (PIP2IT) is being built to retire technical risks associated with acceleration at low energies. As of now, the Warm Front End - a 15 mA DC, 30-keV H- ion source, a 2 m-long Low Energy Beam Transport (LEBT) and a 2.1 MeV CW RFQ, followed by a 10 m Medium Energy Beam Transport (MEBT) - has been assembled and commissioned. One-plane beam phase portraits were recorded in the MEBT with an Allison scanner and analyzed in action-phase coordinates. This report describes the found beam distribution and presents the most important measurements performed with the scanner.Wednesday, June 5, 2019 at 3:00 pm
Speaker: Stanislas Baturin, University of Chicago
Title:Advanced accelerator concepts: two different perspectives towards design of the future accelerators
Abstract:
In this talk, I will present recent theoretical results, performed in collaboration with UCLA, exploring the use of the flat beams to improve the performances of beam-driven acceleration. I will outline two experiments under preparation at the Argonne Wakefield Accelerator facility and discuss their potential outcome. In a second part of the talk, I will present a novel approach to the design of the nonlinear lattice that preserves Hamiltonian that was developed within the Center for Bright Beams. After establishing the connection between a piece of nonlinear lattice and high order simplistic integrator of the Hamiltonian in normalized coordinates, I will show that Hamiltonian preserving lattice could be implemented by just several magnets. I will discuss a possible experimental test of the concept in the IOTA ring.Thursday, June 06, 2019 at 4:00 pm
Speaker: Hiroshi Kawata, KEK
Title: Present status of the compact ERL - Topics about the industrial application
Abstract:
From the 2016 fiscal year, the purpose of the development of the ERL technologies completely moved to the industrial application from the future light source. According to this decision, there are two industrial application programs based on CW superconducting accelerator of the compact ERL (cERL), now. One is RI manufacturing of 99Mo production for nuclear medical examination in cERL. Another is the project of "Development of high-power mid-infrared lasers for highly-efficient laser processing utilizing photo-absorption based on molecular vibrational transitions" by producing high intensity IR-FEL source using cERL with the support from NEDO#. Especially, the latter can be regarded as the POC of the EUV-FEL light source for future lithography. I will give a talk about the present status of the cERL and also industrial application which is progressing now.Tuesday, June 18, 2019 at 4:00 pm
Speaker: Alexander Valishev, FNAL
Title: Highlights of the First IOTA Run: Commissioning and Research
Abstract:
The Integrable Optics Test Accelerator (IOTA) at Fermilab Accelerator Science and Technology (FAST) facility is the latest accelerator constructed and commissioned at the laboratory. The ring assembly was completed in July of 2018 and the beam commissioning commenced shortly thereafter with first circulation of electron beam established on August 21 at the energy of 47 MeV. The capture of 100 MeV beam was achieved in October followed by a period of systems commissioning, which led to the first period of accelerator science research in February-March of 2019. The research at IOTA focused on the demonstration of nonlinear integrable optics for improvement of stability of high-intensity beams but also covered a wide range of complementary beam physics experiments. This talk summarizes the lessons learned during the IOTA beam commissioning and presents the highlights of the experimental results.Thursday, June 20, 2019 at 4:00 pm
Speaker: Daniele Paradiso, UTK
Title: Preparation and Characterization of Pure and Decorated Metal Oxide Materials for Energy Applications Using Novel Physical Deposition Methods
Abstract:
Changes in the global climate, especially noticeable by recent storms and significant weather variations, have led to an urgent need to understand if and/or how these changes are related to CO2 and methane emissions. In concert with understanding this relationship it is incumbent on the scientific community to discover and develop more sustainable and efficient ways to produce and store energy. Because of their abundance and broad range of optoelectronic and physicochemical properties, metal oxides (MO) offer a unique opportunity to address these energy/environmental challenges. Our research activities are focused on the study of pure and decorated nanoscale particles of magnesium (MgO)and zinc oxide (ZnO) and their applicability to optoelectronics, catalysis, gas separationstorage and anti-fungal/bacterial properties. The MO we employ are synthesized using patented and novel approach which produces chemically and size selective particles. These particles can be subsequently decorated using an innovative physical vapor deposition (PVD) process that is used to deposit atomic clusters of copper, nickel and cobalt on MgO and ZnO. Powder X-ray diffraction, photoluminescence (PL), and diffuse reflectance (DR) spectroscopy have been used to examine the structural and optoelectronic properties of the bare and decorated materials. Diffraction data clearly show the emergence of ordered metal structures on the MO; while PL and DR results indicate a potential modification of the absorbing and emitting sites on the surface. Electron microscopy measurements have revealed a presence of metal species on the MO surface. Finally, in order to more fully understand the electronic properties of these decorated MO materials, photoemission studies are currently being performed.Friday, June 21, 2019 at 11:00 am
Speaker: Mario Milazzo, MIT
Title: BioRobotics and MAteriomics: tools and approches for scientific and technologic advancements
Abstract:
Part 1: BioRobotics is a multidisciplinary field in which scientists with different backgrounds aim to solve unanswered questions related to Nature and living organisms, as well as to create new devices for improving healthcare. After a preliminary introduction of the field and possible applications, a selection of "human in loop" case studies will be presented by discussing the approach and the main tools employed to meet the desired goals. Part 2: Materiomics is a new emerging field that aims at studying properties of materials at all scales. Investigating hierarchical structures leads to a wide range of opportunities for scientific and technological advancements in terms of materials development as well as of unveiling basic physico-chemical mechanisms with tremendous implications at the macro-scale. Collagen-based materials will be used as case study to present selected advancements in this field.Tuesday, June 25, 2019 at 4:00 pm
Speaker: Toshiki Tajima, University of California
Title:Wakefield Acceleration in Nanostructures
Abstract:
Wakefield acceleration is a collective acceleration. Thus it is coherent and nonlinear composed of collective fields, as opposed to the conventional acceleration. Laser or charged particle beam bunches can excite wakefields. With the advent of CPA and Thin Film Compression (TFC) we can now envision singler-cycled relativistically compressed X-ray laser. Such a laser has a path toward EW class. Wakefield acceleration in nanostructures is now conceivable because of these technical advances [1]. A nanostructure provides an ideal accelerating medium that has a hole in which electrons (or other charged particles) are accelerated without crystal's heavy electronic collisions, while nanomaterial's electrons provide very intense well-collimated wakefields on the order of TeV /cm, thus opening the TeV-on-a-chip paradigm. (If the luminosity is not a requirement for a certain class of physics, perhaps PeV accelerator is not out of reach, which gives another new paradigm of "non-luminosity paradigm" at extreme energies for physics without luminosity). Meanwhile, for high repetition high luminosity purposes, we can adopt yet another new laser technology of CAN (Coherent Amplification Network) fiber lasers. This allows us to make micron fiber-based laser accelerator systems. One of the applications of this method is a fiber-laser driven medical accelerators. I envision that this accelerator is so tiny that a surgeon may use it as a part of endoscope to carry out endoscopic radiotherapy (ESRT) and carry out theranostics. Finally, we are reminded by Mother Nature that wakefield acceleration was invented many billions of years ago, seen such as in BLAZAR' jet acceleration and its gamma bursts. [1] T. Tajima, Eur. Phy. J. 223, 1037 (2014).Thursday, June 27, 2019 at 4:00 pm
Speaker: William Pellico, FNAL
Title:PIP successfully completes goals - helps prepare PIP II for a bright future
Abstract:
The Proton Source accelerator complex at Fermi National Accelerator Laboratory (FNAL) has just successfully completed an 8-year upgrade project called the Proton Improvement Plan (PIP). This was a significant upgrade and modernization of the oldest accelerators in the nation's high energy physics (HEP) laboratory. The PIP objective was to implement changes to the Pre-Accelerator, Linac and Booster accelerators to enable Fermilab to meet the required proton flux and to ensure viability and reliability for the next 15 to 20 years. The plan addressed the required hardware modifications for doubling the beam cycle rate from 7.5 to 15 Hz, doubling of the proton flux while maintaining 2010 tunnel activation levels. The successful completion of PIP also ensured the viable operation of the Linac through 2025 and the Booster through 2030. PIP has provided the guide for how risks associated with high cycle and flux rate operations could be reduced. With the PIP II effort ramping up, PIP provides the lessons learned and guidance for this new effort.Tuesday, July 9, 2019 at 4:00 pm
Speaker: Salvatore Di Carlo, LAL
Title:Monitoring the beams at the interaction point of SuperKEKB
Abstract:
SuperKEKB is the first electron-positron collider adopting the nano-beam scheme and it is currently under commissioning at KEK. The main goal for SuperKEKB is to achieve a very high design luminosity of 8*10^(35)cm^(-2)s^(-1), through unprecedented performance improvements and technological developments that could be applied in the future to other circular electron-positron colliders. SuperKEKB explores new luminosity frontiers by operating in a regime with strong sensitivity to small parameter changes. The success of the project therefore depends strongly on the capability to properly monitor and control the position and size of the beams. In this talk, I will focus on two monitoring systems: LumiBelle2 and the LABM. LumiBelle2 is a device able to simultaneously deliver the 1kHz integrated luminosity and the 1Hz bunch-by-bunch luminosity with 1% precision, provide luminosity signal to stabilize the beam in the presence of horizontal vibrations, estimate the size of the beams and provide guidance to operate optical correction at the interaction point (IP). LumiBelle2 uses sCVD diamond detectors located in both the electron and positron rings to measure Bhabha events at vanishing scattering angle. The Large Angle Beamstrahlung Monitor (LABM) is a direct monitor of the beam parameters at the IP. The LABM consists of four narrow angle telescopes which collect light from the IP, divide it into two polarizations and four wavelengths, and count photons by means of 32 total photomultipliers.Thursday, July 11, 2019 at 4:00 pm
Speaker: Timofey Zolkin, FNAL
Title:Canonical perturbation theory for symplectic mappings
Abstract:
In this talk we present a canonical perturbation theory for mappings based on the construction of an approximated invariant of motion and further extraction of dynamical properties of the system from this invariant such as the action-angle variables and rotation number. This perturbation theory has a very clear geometrical meaning and retains validity at the resonant conditions. In addition, in the first two orders of perturbation, it allows the extraction of an exactly integrable system of McMillan-Suris kind which we will demonstrate to be a generalization of Courant-Snyder invariant and leads to introduction of nonlinear optical functions. As an examples, we will consider 2D maps of the plane (e.g. Henon and Chirikov mappings) and the application of this theory for better design and understanding of the resonant slow extraction scheme for the Mu2e experiment.Thursday, July 18, 2019 at 4:00 pm
Speaker: Alysson Gold, Stanford University
Title:Applications of Lagrangian Field Theory in Computational Beam-Wave Modeling
Abstract:
Modeling the non-linear interaction between intense charged particle beams and electromagnetic fields in beam-based radiation sources, from klystrons to free electron lasers, has historically been addressed through semi-analytical models. Through recent advances in manufacturing and materials science, we can now realize structures and interaction topologies which are vastly more complex than in current devices unintuitive configurations with the potential to overcome traditional limits in interaction efficiency and output power. These device concepts lie beyond the assumptions of semi-analytical models, however. To address this issue, we present a highly general modeling approach which applies abstract concepts from Lagrangian mechanics, classical and quantum field theory and differential geometry to the concrete challenge of full-wave electromagnetic finite element analysis. Through this unique field theory perspective, we overcome several open problems in steady-state beam-wave modeling, from the interpolation of the current density from particle trajectories (where we demonstrate an 80x improvement in accuracy over existing state-of-the-art approaches), to the revival of the traditional nodal finite element framework for the solution of electromagnetic fields.Monday, July 22, 2019 at 4:00 pm
Speaker: Jeffrey S. Eldred, FNAL
Title:Challenges and Studies for PIP-II Booster
Abstract:
PIP-II is a set of upgrades and improvements to the Fermilab proton complex that are part of the core strategy for Fermilab HEP program for the next decade. PIP-II not only entails a new superconducting linac but also achieving new performance benchmarks forthe Booster. I will provide a brief overview of Booster upgrade activities and focus my discussion on transverse beam dynamics lattice design, betatron resonances, space-charge emittance growth, collective instabilities, and injection region design. Transverse beam dynamics at the Booster has attracted international interest, with recent visitors from Japan, CERN, GSI, Radiasoft taking part in dedicated Booster beam studies. I describe our plan to build on those beam studies to make operational improvements for the Booster in preparation forPIP-II era beam intensity.Tuesday, July 23, 2019 at 4:00 pm
Speaker: Matthew Alexander Fraser, CERN
Title:Overview of Slow Extraction Progress & Development at CERN
Abstract:
Annual high intensity requests of over 1e19 protons on target (POT) from the CERN Super Proton Synchrotron (SPS) Fixed Target (FT) physics programme continue, with the prospect of requests for even higher, unprecedented levels in the coming decade. A concerted and multifaceted R&D effort has been launched to understand and reduce the slow extraction induced radioactivation of the SPS and to anticipate future experimental proposals, such as SHiP [1] at a future SPS Beam Dump Facility (BDF) [2], which will demand a several-fold increase in proton flux. The seminar will outline the operational improvements and recent advances that have been made to significantly reduce the slow extraction losses with the deployment of new extraction concepts, including passive and active (thin, bent crystal) diffusers and extraction on the third-integer resonance with octupoles. The progress made in improving the SPS reproducibility and spill quality will also be detailed before an outlook and implications for future SPS FT operation will be presented. References [1] A. Golutvin et al., A Facility to Search for Hidden Particles (SHiP) at the CERN SPS, Rep. No. CERN-SPSC-2015-016 (SPSC-P-350), CERN, Geneva, Switzerland, Apr. 2015. [2] M. Lamont et al., SPS Beam Dump Facility Comprehensive Design Study, Rep. No. CERN-PBC-REPORT-2018-001, CERN, Geneva, Switzerland, 11 Dec 2018.Tuesday, July 30, 2019 at 4:00 pm
Speaker: Sergey Antipov, CERN
Title:Beam stability challenges for High Luminosity Large Hadron Collider
Abstract:
The High-Luminosity upgrade of the Large Hadron Collider (HL-LHC) will double its beam intensity for the needs of High Energy Physics frontier. This increase requires a reduction of the machine's impedance to ensure coherent stability of the beams until they are put in collision. In this talk I will discuss two key components of the upgrade: the collimation and the crab cavity systems, focusing on the limitations they provide, recent measurements and mitigation strategies. I will also present the first results of the proof-of-principle test of quantifying the strength of Landau damping, generated by LHC octupoles, using a feedback acting as a controllable source of beam coupling impedance.Tuesday, August 06, 2019 at 4:00 pm
Speaker: Vladimir Shiltsev, FNAL
Title:Path to intense accelerator-based neutrino beams
Abstract:
High energy and high beam power accelerators are extensively used for the neutrino physics research. At present, the leading operational facilities are the Fermilab Main Injector complex that delivers over 0.75 MW of 120 GeV protons on the neutrino target, and the J-PARC facility in Japan which recently approached 0.5 MW of the 30 GeV proton beam power. I will present the status and planned upgrades of the Fermilab and J-PARC accelerators and proposals for the next generation accelerator-based facilities world-wide, their challenges and required and ongoing accelerator R&D programs aimed to address corresponding cost and performance risks.Tuesday, August 13, 2019 at 4:00 pm
Speaker: Ingo Hofmann, GSI
Title:Resonant space charge effects in high intensity accelerators
Abstract:
In high intensity linear or circular accelerators space charge is not only a source of tune spread and shift, but also of various resonant phenomena. They may have an impact on lattice design, the choice of working points and/or or lead to beam degradation. Conclusive experimental data on the role of such space charge resonances are not easy to obtain - in some cases also comparison with theoretical models is challenging and a matter of discussion. In this talk, we first consider applications to high intensity linacs: the effects of space charge on halo coupling; and possibilities to work above the conventional 90 degrees longitudinal resonance stopband. For circular accelerators we discuss the issue of incoherent and coherent resonances, the effect of self-consistency and of Landau damping. Furthermore, second and higher order incoherent/coherent space charge resonances and their possible role in explaining recent observations of beam loss in the CERN PS are discussed.Thursday, August 15, 2019 at 4:00 pm
Speaker: Alexander Zlobin, FNAL
Title:Development and First Test of the US-MDP 15T Nb3Sn Dipole Demonstrator (MDPCT1)
Abstract:
U.S. Magnet Development Program (US-MDP) has developed a 15 T Nb3Sn dipole demonstrator for a post-LHC hadron collider. The magnet design is based on 60mm aperture 4layer shell-type coils, graded between the inner and outer layers to maximize the magnet performance. The coils are made of two Rutherford cables, the cable in the two innermost layers consists of 28 strands 1.0 mm in diameter and the cable in the two outermost layers 40 strands 0.7 mm in diameter. Both cables were fabricated at Fermilab using RRP Nb3Sn composite wires produced by Bruker-OST. An innovative mechanical structure based on aluminum clamps and a thick stainless steel skin was developed to preload brittle Nb3Sn coils and support large Lorentz forces. The maximum field for this design is limited by 15 T due to mechanical considerations. The first magnet assembly was done with lower coil pre-load to to achieve 14 T and minimize the risk of coil damage during assembly. The design of the 15 T dipole demonstrator and the details of the magnet assembly procedure as well as the first results of magnet cold tests including quench performance and magnetic measurements will be presented and discussed.Tuesday, August 20, 2019 at 4:00 pm
Speaker: Eric Stern, FNAL
Title:PIC Simulations of Space Charge Compensation with Electron Lens
Abstract:
Space-charge effects set stringent limits on the performance frontier high power proton accelerators. They manifest themselves in the beam losses and emittance growth. In principle, compensation of the space-charge effects in positively charged proton beams should be possible by negatively charged electron lenses which employ high brightness magnetized and externally controlled electron beams. While the method was previously assessed theoretically and in simplified tracking simulations, it has never been modeled by PIC codes to get reliable quantitative estimates of the efficiency of the compensation. Here we report on the first evidence using the Synergia particle-in-cell simulation code that a suitable number of electron lens type elements can protect the machine from emittance growth caused by space-charge forces in a model beam optics lattice with imperfections. For the effective electron lens space-charge compensation, the compensating elements must be placed within the betatron phase advance from each other. Electron lens elements could become the basis of new generation of high power proton and ion rapid cycling synchrotrons.Thursday, August 22, 2019 at 4:00 pm
Speaker: Maria Baldini, FNAL
Title: Road to Room-Temperature Superconductivity: Superhydrides under Pressure.
Abstract:
Two hydrogen-rich materials: H3S and LaH10, synthesized at megabar pressures have revolutionized the field of superconductivity by providing a first glimpse into the solution for the hundred-year-old problem of room-temperature superconductivity. The mechanism governing these exceptional superconductors is the conventional electron-phonon coupling. This talk provides a brief historical overview of the theoretical predictions together with background on motivations and techniques that lead to the subsequent experimental confirmation. Theoretical calculations using density-functional based structure-search methods combined with BCS-type models predicted a new class of dense, hydrogen-rich materials (superhydrides (MHx, with x > 6 and M selected rare earth elements)) with superconducting critical temperatures (Tc) in the vicinity of room-temperature at Mbar pressures. The existence of a series of these phases was subsequently confirmed experimentally, and techniques were developed for their syntheses and characterization, including measurements of structural and transport and magnetic properties, at megabar pressures. Experimental results will be discussed on both sulfur and lanthanum hydrides together with possible strategies to optimize pressure and transition temperatures in conventional superconducting materials. The talk highlights the novel physics in hydrogen-rich materials at high densities, the success of materials by design in the discovery and creation of new classes of superconductors with Tc at and above room temperature.Tuesday, August 27, 2019 at 4:00 pm
Speaker: Trevor Butler, FNAL
Title: NAPAC Preview: Development of a Marx Modulator for FNAL Linac
Abstract:
A Marx-topology modulator has been designed and developed at the Fermi National Accelerator Laboratory under the Proton Improvement Plan (PIP). This modulator replaces the previous triode hard-tube design, increasing reliability, lowering operational costs, and maintaining waveform accuracy. The Marx modulator supplies the anode of the 7835 VHF power triode tube with a 35 kV, 375 Amp, 460 s pulse at 15 Hz. It consists of 54 individual Marx cells, each containing a 639 F capacitor charged to 900 Volts, combined in series with IGBT switches to create the desired output waveform, which requires variable rise and fall times, flattening of capacitive droop, and feedforward beam loading compensation. All five 201.25 MHz RF systems have been upgraded to Marx modulators to ensure continued operation of the linear accelerator.Speaker: Bruce Brown, FNAL
Title: NAPAC Preview: Design Considerations and Operational Features of the Collimators for the Fermilab Main Injector and Recycler
Abstract:
The Fermilab Main Injector system delivers 700 kW of 120 GeV Proton beam for neutrino experiments. Since 2013 this has been achieved using slip stacking accumulation in the Recycler with up to 12 batches from the Fermilab Booster per Main Injector Ramp Cycle. To control activation from beam loss, collimation systems in the Booster to Recycler transfer line, in the Recycler and in the Main Injector are employed. Residual radiation measurements around the ring with detailed studies at the collimators are required to maintain adequate loss control. We will review design considerations, operational parameters and activation results for more than ten years of operation. Simulations with MARS15 are used to explore the activation rates and the isotopic composition of the resulting activation.Thursday, August 29, 2019 at 4:00 pm
Speaker: Sergei Nagaitsev, FNAL
Title: NAPAC Preview: Review of Recent Advances in Cooling Techniques
Abstract:
Beam cooling plays an important role in future electron-ion colliders. The talk will review recent advances in cooling techniques. It will especially discuss variants of electron cooling such as coherent and micro-bunched electron cooling. Other cooling techniques, e.g. optical stochastic cooling, will also be presented.Tuesday, September 17, 2019 at 4:00 pm
Speaker: Alexander Romanov, FNAL
Title: A Framework for Beam-Optics Tuning with Applications to the Commissioning of IOTA and the Fermilab Accelerator Complex
Abstract:
In preparation for the IOTA ring commissioning, a comprehensive framework for beam-optics tuning has been developed and tested during the FAST superconducting linac operations. The software system played an important role in establishing beam circulation and precise lattice adjustments for various IOTA experiments in the first research run in 2018-2019. The software uses an extended LOCO algorithm with a strong emphasis on the online tuning capabilities that require tight integration with a control system. The integration with ACNET allowed using the same framework to study and optimize other beamlines of the Fermilab complex, including the transfer lines for Muon g-2, Mu2e and the Delivery Ring. A part of the computational code used for matching lattices to experimental data was successfully applied to the design of lattice options for the IOTA experiments, FAST linac, and several other cases.Tuesday, September 24, 2019 at 4:00 pm
Speaker: Daniel Broemmelsiek, FNAL
Title: FAST SRF Linac: Commissioning, Operations and Research in 2018-2019
Abstract:
The Fermilab Accelerator Science and Technology (FAST) facility employs an electron linear accelerator based on superconducting RF (SRF) technology. We report on the commissioning and performance of this SRF electron linac. We also discuss opportunities for further beam studies and tests at FAST, including tests of novel instrumentation and system performance with beam meeting the International Linear Collider (ILC) beam specifications.Tuesday, October 15, 2019 at 4:00 pm
Speaker: Nikolai Mokhov, FNAL
Title: MARS Mission: Monte Carlo Code and its Applications
Abstract:
The MARS code system is a set of Monte Carlo programs for detailed simulation of hadronic and electromagnetic cascades in an arbitrary geometry of shielding, accelerator, detector and spacecraft components with energy ranging from 10^-5 electronvolt up to 100 TeV. It was originated in 1974 at MEPhI (Moscow), and developed since at IHEP (Protvino), SSCL (Texas) and Fermilab. Current MARS15 combines well established theoretical models for strong, weak and electromagnetic interactions of hadrons, heavy ions and leptons with a system which can contain millions of objects, ranging in dimensions from microns to hundreds of kilometers in the same setup. MARS is especially powerful in accelerator, beamline and machine-detector interface applications including but not limited to radiation protection, shielding design, environment control, radiation damage, and materials research. The code was used in design of accelerator systems at U-70, UNK, Tevatron, Main Injector, Booster, SSC, LHC, NLC, TESLA, ILC, KEK, J-PARC, ESS and muon colliders: beam abort, beam stops, scrapers, collimators, beam transfer lines, beam loss monitors, interaction regions, target stations, and pioneering scheme of protection of superconducting magnets against deleterious radiation effects. Another class of MARS use is design of various detector and experimental setup components: experiments at U-70 and UNK at IHEP; D0, CDF, BTeV, E-853, T-864, E-872, NuMI/MINOS, Mu2e, LBNF, g-2 and SeaQuest at Fermilab; SFT, EMPACT, GEM, SDC and FAD at SSC; CMS at LHC as well as detectors for electron and muon colliders.Thursday, October 17, 2019 at 4:00 pm
Speaker: Toshiyuki Mitsuhashi, KEK
Title:Optical Diagnostics for beam halo
Abstract:
Diagnostics of beam halo is important issue especially for machine protection in the high intensity machines. The coronagraph, very special telescope which is designed to observe sun corona by Lyot is applied to beam halo diagnostics. The beam core is masked with opaque disk like eclipse, and surrounding week structure is observed with a contrast of 10^6. In this lecture, I would like to introduce the physics of coronagraph, and measurement result in PF, KEK. I will briefly introduce beam halo diagnostics at LHC with coronagraph, and also introduce a dedicated design for reflective objective system to new coronagraph for the LHC and SuperB. If the time is remained, I will touch a screen-monitor based beam halo measurement at J-PARC.Monday, October 21, 2019 at 4:00 pm
Speaker: Didier Uriot, CEA-Saclay/DSM/Irfu/SACM
Title: Latest comparisons between TRACEWIN and experimental results for IFMIF, IPHI and Spiral2 projects.
Abstract:
For several decades, CEA Saclay has been involved in the study and construction of high intensity linear accelerators, such as ESS, IPHI, SPIRAL2, IFMIF, SARAF, FAIR, LINAC4 or MYRRHA. The beam dynamics of these high intensity accelerators has been simulated mainly using the beam dynamics code TRACEWIN developed at CEA since 15 year. These last years, several of these long-standing projects have entered the commissioning phase showing good agreement between experimental results and TRACEWIN. Numerical studies and experimental results concerning the projects IFMIF, IPHI and Spiral2 will be discussed during the presentation.Tuesday, October 22, 2019 at 4:00 pm
Speaker: Ewen MacLean, CERN
Title: Beam-based nonlinear optics studies at the LHC
Abstract:
Precise optics control is essential for safe and efficient operation of the LHC at CERN. Traditionally much attention has focused on the linear optics, however over the first two operational runs an increasing proportion of machine time has also been devoted to beam-based study and correction of nonlinear optics in the LHC. This talk will present some highlights of the nonlinear optics commissioning and machine development programs at the LHC.Tuesday, November 5, 2019 at 4:00 pm
Speaker: Jae-Yel Lee, Northwestern University
Title: Microstructural control of Nb3Sn coatings on Nb for high-performance Nb3Sn SRF cavities
Abstract:
There has been significant progress in Nb3Sn SRF cavities recently. Nb3Sn SRF cavities begin to exceed 20 MV/m for a single-cell and 10 MV/m for nine-cell cavities at 4K. There have been efforts to understand the performance limiting imperfects in Nb3Sn coatings on Nb: patchy regions with extremely thin grains, grain boundary (GB) segregations, and surface roughness. We find the causes of the imperfections: thin-grains are correlated to the texture of Nb3Sn on Nb, GB segregation is caused by Sn and Nb diffusion along GBs, and surface roughness is related to the grain size of Nb3Sn coatings. They can be mitigated by the optimum growth process of Nb3Sn coating such as Sn supply and growth temperatures, which lead to the high-performance Nb3Sn cavities. We demonstrated that high-performance Nb3Sn cavities can be achieved by controls of texture, chemical composition of GBs, and surface roughness of Nb3Sn coatings on Nb during the coating process, and the possible roles of materials science in the challenges in accelerator technologies will be discussed.