Accelerator Physics and Engineering Seminars: Archive

Below is a list of past seminars related to the Accelerator Science and Engineering Traineeship (ASET) program.

The ASET program at MSU leverages unique campus-based equipment, systems, and experts at FRIB, extensive ASET faculty and research support in several MSU academic programs, and resources at U.S. Department of Energy national laboratories. 

2022

22 April 2022
Overview of the Electron-Ion Collider (EIC)
Christoph Montag, Brookhaven National Laboratory

The EIC currently being designed by a partnership between Brookhaven National Laboratory and Jefferson Lab will open exciting new frontiers for research in nuclear physics and quantum chromodynamics. The potential and the associated design requirements of the facility are laid out in detail in a comprehensive White Paper that has been compiled by the U.S. nuclear physics community with world-wide support. An overview of the facility will be given, and latest design advances will be presented.

8 April 2022
Machine Learning to Improve the Operation of the Spallation Neutron Source
Willem Blokland, Oak Ridge National Laboratory

At the Spallation Neutron Source at Oak Ridge National Laboratory, research in collaboration with Jefferson Laboratory is ongoing to improve the accelerator and target operations using Machine Learning (ML). ML has the capability to see correlations in the data where other methods cannot and, through surrogate models, provide much faster simulation. After a short introduction to ML, the talk will discuss four use-cases: Predicting upcoming errant beam pulses by analyzing data from a beam current monitor, improve the mercury filled high power target using surrogate modeling, use time-series ML methods to model the High Voltage Converter Modulator to estimate hardware components’ remaining lifetimes, and use data-driven ML methods to improve the Cryogenic Moderator System response to beam on-off events. Initial results will be discussed, as well as the infra-structure that was set up to collect data and the tools to work with a remote team.

25 March 2022
In Pursuit of Next Generation Particle Accelerators
Emilio Nanni, SLAC National Accelerator Laboratory

Accelerators ranging from midscale radio frequency photo injectors for femtosecond electron-diffraction experiments, to kilometer-long free electron lasers that produce femtosecond x-ray pulses are utilized to resolve materials with atomic precision on femtosecond timescales. While the performance and recent results of these facilities are extraordinary, ensuring their continued vitality requires us to explore new accelerator physics and innovate the next generation of technology. One approach to achieving performance and accelerating gradients orders of magnitude above present capabilities is to dramatically increase the operational frequency into the Terahertz (THz) range. We are exploring accelerating structures designed to withstand high gradients and able to manipulate high-charge beams on femtosecond timescales, developing novel electronic and photonic THz sources, and laying the foundation for THz accelerator technology. Results from recent experiments on high-gradient THz accelerators and their application to time stamping and electron bunch compression for ultrafast electron diffraction will be presented, along with a future outlook for the field.

25 February 2022
Application of Lasers for Diagnostics of Negative Hydrogen Beams
Alexander (Sasha) Aleksandrov, Oak Ridge National Laboratory

Talk abstract: Beam diagnostics for resolving internal structure of a beam in an accelerator use interaction of the beam particles with a probe that can be inserted in the beam. Many types of probes can be used for this purpose, from a simple wire to a beam of different particles. Negative ions of hydrogen (H-) are widely used in initial stages of high-intensity circular proton acceleration. These particles interact efficiently with photons, therefore, a laser beam makes an ideal probe for diagnostics of H- beams. Lasers can be used to measure many important beam parameters: transverse and longitudinal beam size, transverse and longitudinal emittances, beam energy and intensity. A review of the laser-based beam diagnostics will be given in this talk. Most of the material is based on the experience from the Spallation Neutron Source, the world highest power H- accelerator.      

11 February 2022
The Upgraded Injector Test Facility at Jefferson Lab
Matthew Poelker, Jefferson Lab

The Upgraded Injector Test Facility at Jefferson Lab is a compact superconducting radio frequency (SRF) linac that can provide spin polarized electron beam at energy up to 10 MeV. In this talk, I describe the facility and the performance of the novel SRF cryomodule used to accelerate the beam. I will present brief descriptions of two inaugural studies performed at the facility, and discuss possible future applications.   

28 January 2022
DC Photoemission Guns and a Quest for Higher Operating Voltage
Carlos Hernandez-Garcia, Thomas Jefferson National Accelerator Facility

Talk abstract: High voltage DC photoemission electron guns have demonstrated high performance for a variety of meaningful accelerator applications, including:

  • Ultra-high vacuum required for obtaining long-photocathode lifetime from high polarization GaAs photocathodes for nuclear physics
  • Generating tens of mA for electron coolers, energy recovery linacs, and free-electron lasers
  • Bright electron beams for electron microscopy and for ultra-fast electron diffraction

The photocathode accelerating field must be sufficiently high (often > 10 MV/m) to compensate for high bunch charge and improve injector transmission, imposing challenging requirements to reliably apply high voltage to the electrodes and HV feedthroughs without breakdown. Further, the electrodes must be free of field emission to preserve the vacuum conditions necessary for long photocathode lifetime. At Jefferson Lab, we have developed compact DC high voltage photoguns based on an inverted-geometry ceramic insulator concept. Our design is based on achieving exceptional vacuum, being free of field emission and operating with reliable approaches to applying high voltage to the photogun. I will provide an overview of DC photogun designs in operational accelerators, practical considerations to reliably apply high voltage, and summarize both successes and failures learned over the two past decades in building these photoguns.

14 January 2022
EDM Measurement in Small Rings
Vasiliy Morozov, Oak Ridge National Laboratory

Talk abstract: V.S. Morozov1, R. Suleiman2, and Ya.S. Derbenev2 present a new design of highly-specialized small storage rings for low-energy polarized electron beams. The new design is based on the transparent spin methodology that cancels the spin precession due to the magnetic dipole moment at any energy while allowing for spin precession induced by the fundamental physics of interest to accumulate. The buildup of the vertical component of beam polarization can be measured using standard Mott polarimetry that is optimal at low electron energy. These rings can be used to measure the permanent electric dipole moment of the electron, relevant to CP violation and matter-antimatter asymmetry in the universe, and to search for dark energy and ultra-light dark matter.

1Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
2Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA

2021

17 December 2021
Making Molecular Movies with MeV Electrons
Xiaozhe Shen, SLAC National Accelerator Laboratory

Talk abstract:Visualization of structural changes of materials with atomic spatial (Angstrom) and temporal resolutions (femtosecond) is of crucial importance to the understanding of the relation between structure and functionality, and the ultimate goal of controlling energy and matter[1]. In the past decades, ultrafast electron diffraction/microscopy (UED/UEM) has been rapidly developing, aiming to provide the relevant length and time scales for ultrafast science[2-3]. With the advent of high accelerating gradient radiofrequency photoinjector, high brightness electron beam at mega-electron-volt (MeV) energy has become accessible for UED to reach ~1 Å spatial resolution and ~100 femtosecond temporal resolution. In 2014, SLAC National Accelerator Laboratory launched a UED/UEM initiative, aiming to provide the world’s leading ultrafast electron scattering instrument using MeV electron beams. A prototypical MeV UED beamline was built and has been evolving over the years[4-6] for the goal that has long been envisioned—making space-and-time resolved molecular movies. A great number of successful ultrafast scientific results have been achieved at SLAC MeV UED in the regions of condense matter physics, warm-dense matter physics, as well as chemical science[7-9]. Since 2019, SLAC MeV UED has become an official user facility as part of Linac Coherent Light Source to serve the ultrafast science community[10]. In this talk, the experimental set up of SLAC MeV UED and selected ultrafast scientific results will be presented. Research and development efforts to further expand the capabilities of SLAC MeV UED will also be discussed.

[1] "Directing matter and energy: Five challenges for science and the imagination,” A Report from the Basic Energy Sciences Advisory Committee, 2007
[2] R. J. D. Miller, Science 343, 1108 (2014)
[3] Ahmed H. Zewail, Science 328, 187 (2010)
[4] S. P. Weathersby, et al., Review of Scientific Instruments 86, 073702 (2015)
[5] X. Shen, et al., Ultramicroscopy 2018, 184, 172-176
[6] X. Shen, et al., Struct. Dyn. 6, 054305 (2019)
[7] E. J. Sie, et al., Nature 565, 61 (2019)
[8] M. Z. Mo, et al., Science 360, 1451 (2018)
[9] J. Yang, et al., Science 361, 64 (2018)
[10] SLAC MeV UED user facility webpage

3 December 2021
Superconducting Radio Frequency Cavity Fault Classification Using Machine Learning at Jefferson Lab
Chris Tennant, Jefferson Lab

Talk abstract: We report on the development of machine learning models for classifying C100 superconducting radio frequency (SRF) cavity faults in the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab. Of the 418 SRF cavities in CEBAF, 96 are designed with a digital low-level rf system configured such that a cavity fault triggers recordings of rf signals for each of the eight cavities in the cryomodule. Subject matter experts analyze the collected time-series data and identify which of the eight cavities faulted first and classify the type of fault. This information is used to find trends and strategically deploy mitigations to problematic cryomodules. However, manually labeling the data is laborious and time consuming. By leveraging machine learning, near real-time—rather than postmortem—identification of the offending cavity and classification of the fault type has been implemented. We discuss performance of the machine learning models during a recent physics run. We also discuss efforts for further insights into fault types through unsupervised learning techniques, and present preliminary work on cavity and fault prediction using data collected prior to a failure event.

19 November 2021
Accelerator Research at Fermilab's IOTA/FAST Facility
Alexander A. Valishev, Fermi National Accelerator Laboratory

Talk abstract: The Fermilab Accelerator Science Facility (FAST), is a research machine to conduct accelerator proof-of-principle experiments as well as technology development to enable future particle physics accelerator facilities. The centerpiece of the facility is the Integrable Optics Test Accelerator (IOTA), a small storage ring designed to satisfy the requirements of a diverse beam physics research program using either electron or proton beams. This talk will discuss some of the challenges of accelerator physics and how the IOTA/FAST experimental program addresses them. The covered topics include nonlinear beam dynamics, beam instabilities, beam cooling, and photon science.

5 November 2021
Particle-Matter Interaction Simulations in Accelerator Applications
Dali Georgobiani, Fermi National Accelerator Laboratory

Talk abstract: An overview of underling physics in high-energy or/and high-power particle beam interactions with matter in accelerator applications and its implementation in the Monte Carlo simulations is presented and discussed. Effects in materials under irradiation, materials response related to component lifetime and performance are considered with a focus on existing and future accelerator complex needs. The implementation of this multi-faceted physics and adequate state-of-the art computing techniques in the modern Monte Carlo codes, code main features, results of the code benchmarking, validation, and intercomparison are described.

22 October 2021
Plasma Processing Boosts the Energy of the Spallation Neutron Source Superconducting Linac
Marc Doleans, Oak Ridge National Laboratory

Talk abstract: The Spallation Neutron Source (SNS) has been in operation for neutron science since 2006 at the Oak Ridge National Laboratory. The SNS provides the most intense, pulsed accelerator-based neutron beams in the world. It uses 1.4 MW of average proton beam power on its liquid mercury target to generate neutrons for research. Most of the proton beam energy is imparted by the superconducting linac portion of the accelerator. In its early years of operation, the superconducting accelerating cavities suffered from excessive parasitic electron activity leading to thermal instability and reduced accelerating gradients. As the result, the proton beam energy remained at 940 MeV, below the SNS design beam energy of 1000 MeV. To remediate this issue, a new in-situ processing technique was proposed and developed. The technique centered on using a plasma inside the resonant cavities to further process their inner RF surfaces and allow increased accelerating gradients. The presentation will cover the successful development and deployment of this new technique leading to a proton beam energy of 1 GeV for neutron production.

8 October 2021
Cathode R&D for High Intensity Electron Source at Brookhaven National Laboratory
Mengjia Gaowei, Brookhaven National Laboratory

Talk abstract: Attaining high quantum yield, low emittance, and long lifetime from an alkali antimonide photocathode has remained a sustained focus in recent years, due especially to the need for electron beams of high average current for strong hadron cooling. The ongoing development of photocathodes is motivated by the unprecedented needs of this application, namely simultaneous optimization among photoemission metrics that tend to be linked by the underlying physics. The challenge of optimizing these processes and their linked photoemission metrics has driven improvements in cathode material characterization and new fabrication techniques. At BNL, a new suite of materials science tools is now available to address the poor crystallinity and lack of surface and bulk engineering that has previously limited the performance of these materials. In situ and real time x-ray characterization study has been performed to reveal the compositional, structural and surface evolution of the alkali-based photocathodes prepared using different growth techniques and recipes, as well as their correlation with quantum efficiency and degradation mechanisms. The structural, stoichiometric and surface information revealed by these measurements are essential for optimizing the cathode quantum efficiency, emittance and operational lifetime for applications in future light sources.

24 September 2021
Advances in Recirculating Superconducting Proton Linac Study 
Ji Qiang, Lawrence Berkeley National Laboratory

Talk abstract: Superconducting proton linacs can be used as a driver for a wide range of applications including spallation neutron source, accelerator driven nuclear energy production, neutrino physics study, and medical application. However, the construction and operation of such a superconducting proton linac is expensive. In this talk, we will discuss a new type of proton linac, recirculating superconducting proton linac, and its recent advances. This accelerator has the potential to substantially reduce the cost of a superconducting proton linac by using much less number of superconducting cavities.

10 September 2021
Injection Technologies for High Power Proton Rings: Present and Future
Sarah Cousineau, Oak Ridge National Laboratory

Talk abstract: High power, pulsed proton rings rely on charge exchange injection to control the phase space density while the charge density of the beam is increased. Traditional charge exchange injection from an H-linac into a ring relies on very thin carbon foils to strip the electrons from the hydride. The presence of the foil material in the path of the beam introduces complications such as scattering of beam resulting in high radiation in the vicinity of injection. Additionally, while foil technology has advanced considerably over the decades with latest foils able to sustain megawatt beam cycles for months, there is still a fundamental beam power density limitation on the foils. Next generation machines will need to rely on alternative methods for charge exchange. One such method under development is the laser assisted charge exchange method (LACE), which utilizes magnets and lasers in place of the foil to remove the electrons. This talk will discuss the successes and limitations of foil technology, and the development of the LACE technique as a candidate for replacing the foils in future high power accelerators.

23 April 2021
The Argonne Tandem Linac Accelerator System (ATLAS) Multi-User Upgrade and New Applications (PDF)
Brahim Mustapha, Argonne National Laboratory

Talk abstract: The recently approved multi-user upgrade of the ATLAS facility at Argonne will enable simultaneous acceleration and delivery of two different ion beams to different experimental areas. In the initial phase, one stable, nearly continuous-wave beam from the Electron Cyclotron Resonance ion source, and one pulsed radioactive beam from the Electron Beam Ion Source charge breeder of the Californium Rare Isotope Beam Upgrade (CARIBU-EBIS) will be interleaved in time via a pulsed electrostatic deflector at injection, and accelerated through the first two sections of the linac. At that point, one of the beams is deflected via a pulsed switching magnet to a lower energy experimental area while the other is further accelerated through the third linac stage of ATLAS and delivered to a higher energy experimental area. Details of the proposed implementation and the expected gains from this upgrade will be presented. In addition to enhancing the ATLAS nuclear physics program, this upgrade will also increase the availability of beam time for applications such as material irradiation, isotope-production research and development, and radiobiology studies with ion beams. A brief overview and typical results from these applications will be presented.

9 April 2021
Fusion Sciences & Ion Beam Technology
Qing Ji and Arun Persaud, Lawrence Berkeley National Laboratory

Talk abstract: We report on two different accelerator technologies being developed at Lawrence Berkeley National Laboratory (LBNL). First, we will describe the Neutralized Drift Compression Experiment-II (NDCX-II) at Berkeley Lab. NDCX-II is a 1 MeV induction LINAC delivering high peak ion current (~ 1 A) of ultrashort pulse length (a few ns FWHM) with a beam spot of 1 mm radius on target. We will discuss its design, control system, and recent experiments. NDCX-II has been in operation for several years. The hot-plate surface lithium ion source has been replaced with a plasma source that can generate proton and helium ions in a large area (~ 6 cm in diameter). Recently, NDCX-II has been used to study radiation effects induced by ions with high fluences and high dose rate in diodes and transistors. Second, we will discuss the development of a multi-beamlet, compact RF accelerator that is fabricated using a stack of inexpensive PCBoard wafers. This is a new implementation of an accelerator design from the 1980’s, but with an order of magnitude reduction in size. We have demonstrated working implementations of the basic components (focusing and acceleration elements) and recently achieved beam energies of 50 keV. The technology can be scaled up to higher currents and MeV beam energies.

26 March 2021
High Gradient C-band Research at Los Alamos (PDF)
Evgenya Simakov and John Lewellen, Los Alamos National Laboratory

Talk abstract: Our talk will report on the design, assembly, and high-power conditioning of the new high-gradient C-band Engineering Research Facility (CERF-NM) at Los Alamos National Laboratory (LANL). At LANL, we commissioned the CERF-NM that is a test stand powered by a 50 MW, 5.712 GHz Canon klystron. The test stand is capable of conditioning single-cell accelerating cavities for operation at surface electric fields up to 300 MV/m. The RF field is coupled into the cavity from a WR187 waveguide through a mode launcher that converts the fundamental mode of the rectangular waveguide into the TM01 mode of the circular waveguide for coupling into the cavity. The test stand is currently fully conditioned to operate at the power of 50 MW, 100 Hz repetition rate, and RF pulse length up to 1 microsecond. The first cavity to be tested for high gradient operation will be a beta=0.5 proton accelerating cavity fabricated at SLAC National Accelerator Laboratory.

It is well-known that a notable bottleneck in achieving high-gradient in RF structures is the onset of RF breakdown. While bulk mechanical properties are known to significantly affect breakdown propensity, the underlying mechanisms coupling RF fields to bulk plastic deformation in experimentally relevant thermo-electrical loading conditions remain to be identified at the atomic scale. In this talk, we will also present results of large-scale molecular dynamics simulations (MD) to investigate possible modes of coupling. We consider the activation of Frank-Read (FR) sources, which leads to dislocation multiplication, under the action of bi-axial thermal stresses and surface electric-field. With a charge-equilibration formalism incorporated in a classical MD model, we show that a surface electric field acting on an either pre-existing or dislocation-induced surface step, can generate a long-range resolved shear stress field inside the bulk of the sample. We investigate the feedback between step growth following dislocation emission and subsequent activations of RF sources and discuss the regimes of critical length-scales and densities of dislocations, where such a mechanism could promote RF breakdown precursors. Some interesting simulation results will be presented and discussed.

12 March 2021
Recent Advances and Breakthrough for Superconducting Radio Frequency Cavities at Fermi National Accelerator Laboratory (PDF)
Martina Martinello, Fermi National Accelerator Laboratory

Talk abstract: The talk will discuss the state-of-the-art surface treatments for superconducting radio frequency cavities, stressing how to obtain both high Q-factor and high-accelerating gradients. The physics underneath performance improvement will be discussed and correlated with material analysis results. The talk will also discuss the technology advances in correlation with LCLS-II HE and PIP-II projects.

26 February 2021
Superconducting Accelerator Magnet Design and Applications
GianLuca Sabbi, Lawrence Berkeley National Laboratory

Talk abstract: 
This presentation will review the fundamentals of superconducting accelerator magnet design, including material properties, magnetic, mechanical and quench protection analysis. Two specific applications will be discussed in some detail: IR quadrupoles for HL-LHC, and magnets for ECR ion sources. Broader applications of high field magnet technology will also be mentioned in areas ranging from NMR/MRI, radiation therapy and fusion energy devices.

12 February 2021
Adaptive Feedback and Machine Learning for Time-Varying Particle Accelerator Systems (PDF)
Alexander Scheinker, Los Alamos National Laboratory

Talk abstract
(PDF)

29 January 2021
Spin Manipulation Experiment in the Relativistic Heavy Ion Collider
Haixin Huang, Brookhaven National Laboratory (BNL)

Talk abstract: The BNL nuclear physics program requires polarized hadron beams in the Relativistic Heavy Ion Collider (RHIC) and Electron-Ion Collider. Frequent reversals of the beam polarization direction in a storage ring can significantly reduce the systematic errors in an experiment’s spin asymmetry measurements. At high energy colliders with Siberian snakes, a more sophisticated spin flipper constructed of nine dipole magnets, was used to flip the spin in the BNL RHIC. A special optics choice was also used to make the spin tune spread very small. The same device was used to drive coherent spin motion to measure the important quantity, spin tune. The principle and experiment results are discussed.

15 January 2021
Electron Cooling in a Collider* (PDF)
Alexei Fedotov, Brookhaven National Laboratory

Talk abstract: High-energy electron cooling is being considered for several accelerator physics projects worldwide, including for the Electron Ion Collider under design at Brookhaven National Laboratory (BNL). Since accelerating DC electron beams above few MeV is technologically challenging, rf-acceleration of electron bunches becomes a practical approach for high-energy applications. A world's first electron cooling of ion beams employing such RF-accelerated electron bunches was recently demonstrated at BNL using the Low Energy Relativistic Heavy Ion Collider (RHIC) electron Cooler (LEReC) [1]. Many challenges associated with such an approach were successfully overcome. The cooling task becomes even more challenging when one attempts to cool ion beams in collisions, requiring careful optimization between the electron cooling process and the ion beam lifetime due to various effects, including the beam-beam interactions. In this presentation, we discuss first successful application of electron cooling technique for colliding ion beams in RHIC. 

[1] A.V. Fedotov et al., “Experimental demonstration of hadron beam cooling using radio-frequency accelerated electron bunches”, Phys. Rev. Letters 124, 084801 (2020)
*Work supported by the U.S. Department of Energy

2020

11 December 2020
Optical Stochastic Cooling at Fermilab’s IOTA Ring
Jonathan D. Jarvis, Fermi National Accelerator Laboratory

Talk abstract: In modern accelerators, the ability to increase or maintain beam density and lifetime is essential. Historically, this has required the development and application of a variety of beam-cooling concepts and technologies to facilitate particle accumulation, higher luminosity and to counteract diffusive (heating) effects, such as intrabeam scattering (IBS), Touschek scattering, and residual-gas scattering. One of the greatest conceptual and technological triumphs in this area was van der Meer’s Nobel-Prize-winning Stochastic Cooling (SC), which was vital in the accumulation of antiprotons and in the delivery of the beam quality required for the discovery of the W and Z bosons. Extension of the SC principle to optical frequencies and bandwidths (Df~1013 Hz) was first suggested in the early 1990s by Zolotorev, Zholents and Mikhailichenko and could increase achievable cooling rates by three to four orders of magnitude. In this talk, we will review the basic concepts of Optical Stochastic Cooling (OSC) and describe the experimental OSC program underway at Fermilab’s Integrable Optics Test Accelerator (IOTA) ring. We will also discuss development efforts focused on high-gain optical amplification for OSC and the use of OSC concepts and technology as a more general tool for phase-space control and measurement.

13 November 2020
Electron Ion Collider and Superconducting Radio Frequency Device Development at Brookhaven (PDF)
Zachary Conway, Brookhaven National Laboratory

Talk abstract: This presentation will overview the superconducting radio frequency devices required for the future Electron Ion Collider and ongoing work at Brookhaven National Laboratory addressing related technical challenges. One of the challenges of operating superconducting resonant cavities in hadron synchrotrons is the need to operate with large frequency sweeps, greater than one percent in some cases during beam acceleration. A physical example of these challenges is found in the refurbished 56 MHz superconducting accelerator system to be installed in the Relativistic Heavy Ion Collider in 2022. The 56 MHz superconducting system addresses synchrotron acceleration via a novel coupler and tuner which damp and detune the resonator during beam acceleration. A full review of the 56 MHz system upgrades and conclusions on how these results may impact plans for the Electron Ion Collider will be discussed.

30 October 2020
National Synchrotron Light Source II: Present Status and Upgrade Plans (PDF)
Guimei Wang, Brookhaven National Laboratory

Talk abstract: The National Synchrotron Light Source II (NSLS-II) is a 3 GeV, low-emittance (H:1 nm-rad and V:8 pm-rad), high-brightness third-generation synchrotron light source at Brookhaven National Laboratory. It is to deliver a broad range of light to 60-70 beamlines at full build-out. The storage ring was commissioned in 2014 and began its routine operations in December of the same year. Since then, we have been continuously installing and commissioning new insertion devices and beamlines. At this point, the facility hosts 28 beamlines to deliver light from infrared to hard x-ray. Over the past five years, the storage ring performance continuously improved, including 500 mA demonstration and 400 mA routine top off operation. In fiscal year 2020, we delivered 5,400 hrs beam time with 97-percent operation reliability. 

Towards the future, a program to explore upgrade paths for the NSLS-II was initiated in 2019, with the goal of dramatically increasing its brightness and flux, which requires significantly lower emittance. Instead of following the Multi-Bend Achromat (MBA) lattice approach, recently we proposed an alternative way to reach low emittance by use of a lattice element that we call "Complex Bend." The Complex Bend is a new concept of bending magnet consisting of a number of dipole poles with strong alternate focusing to maintain the beta-function and dispersion oscillating at very low values, thus reach low emittance. Candidate lattices have achieved ~30 pm-rad emittance with 5 mm on-momentum dynamic aperture to allow off-axis injection.  

16 October 2020
The Recycler and Main Injector in the Megawatt Era (PDF)
Robert Ainsworth, Fermi National Accelerator Laboratory

Talk abstract: As part of the Nova upgrades in 2012, the recycler was repurposed as a proton stacker for the main injector with the aim to deliver 700 kW. Since January 2017, this design power has been run routinely. Looking towards PIP-II, the recycler and main injector will be required to stack and accelerate 50% more beam in order to deliver 1.2 megawatt beam power for LBNF/DUNE. This intensity increase poses serious challenges of which some will be discussed, such as space charge tune shifts during slip-stacking, transition crossing in the main injector and instabilities in both machines. Different schemes to mitigate these issues, such as resonance compensation and a gamma-t jump system will be discussed.

2 October 2020
Accelerator R&D Activities at Argonne National Laboratory (PDF)
John Byrd, Argonne National Laboratory

Talk abstract: I will talk about the wide range of accelerator R&D going on at Argonne National Laboratory. The main activity is the design and construction of a new 6 GeV electron storage ring that will replace the existing Advanced Photon Source (APS) storage ring. When commissioning finishes, planned for 2023, the APS Upgrade will be the world’s  brightest storage ring light source. We are currently engaged in several studies to understand the challenges of very low emittance electron beams. Argonne is also deeply engaged in physics and technology of future light sources. I will touch on activities such as superconducting undulators, low emittance electron sources, x-ray free electron laser oscillators as well a future beam wakefield driven accelerators. 

18 September 2020
Nb3Sn Superconductors for Accelerator Magnets (PDF)
Xingchen Xu, Fermi National Accelerator Laboratory

Talk abstract: 
Nb3Sn, currently the second most-widely used superconductor (second only to NbTi), has important applications in the building of high-field magnets (typically above 10 T) for nuclear magnetic resonance (NMR) devices, particle accelerators, experimental thermonuclear fusion reactors, and other research-use magnets. Nb3Sn is the superconductor of choice to build accelerator magnets for the planned Future Circular Collider (FCC), as the successor to the Large Hadron Collider (LHC). However, the critical current density (Jc - the most important performance index of superconductors - of the state-of-the-art Nb3Sn, which has been at a plateau for nearly two decades, is significantly below that required by the FCC specification at 16 T. On the other hand, a new type of Nb3Sn superconductor we are developing based on the internal oxidation technology, which introduces oxide nanoprecipitates as artificial pinning centers (APC) to Nb3Sn, has demonstrated significantly superior performance to state-of-the-art Nb3Sn, including doubling the Jc at high fields (16 T and above) while significantly reducing the undesirable magnetization at low fields (3 T and below). This talk will discuss the applications of Nb3Sn superconductors in accelerator magnets, their current status, the prospect for a new generation of Nb3Sn superconductors based on the APC technology, and why such conductors, if successful, can be a game changer for future energy-frontier circular colliders.

29 January 2020
Fusion, Beams and Qubits (PDF)
Thomas Schenkel, Lawrence Berkeley National Laboratory

2019

5 December 2019
Accelerator and Beam Physics Research Opportunities at Fermilab (PDF)
Vladimir Shiltsev, Fermi National Accelerator Laboratory

21 November 2019
Particle Accelerators at Los Alamos National Laboratory (LANL) (PDF)
Stephen Milton, LANL

18 September 2019
Physics of Multi-Bend Achromat Lattice (PDF)
Ryan Lindberg, Argonne National Laboratory

20 May 2019
Plasma Spectroscopy Techniques for Diagnosing Plasmas in High Energy Density, Pulsed-Power Accelerators (PDF)
Mark D. Johnston, Sandia National Laboratories

2018

29 November 2018
Los Alamos Accelerator Science and Technology (PDF)
Robert Garnett, LANL

12 September 2018
Nb3Sn SRF Cavity Development at Fermilab (PDF)
Sam Posen, Fermi National Accelerator Laboratory

31 August 2018
High Level Control Room Applications Software at SNS (PDF)
Andrei Shishlo, Oak Ridge National Laboratory

14 March 2018
R&D at JLAB Towards High Performance Superconducting RF Cavities (PDF)
Speaker: Pashupati Dhakal, Thomas Jefferson National Accelerator Facility

2017

10 April 2017
Perspectives on Ultra-Compact High Gradient RF Accelerator Technology and its Application (PDF)
Sami Tantawi, Stanford Linear Accelerator Center