LINAC2024 - 32nd Linear Accelerator Conference

25 Aug 2024, 09:00 → 30 Aug 2024, 16:00 America/Chicago

Grand Ballroom (Hilton Chicago)

John Byrd (Argonne National Laboratory), Sam Posen (Fermi National Accelerator Laboratory)

It is our great pleasure to invite you to the 32^nd Linear Accelerator Conference (LINAC). In 2024, LINAC will come to the heart of downtown Chicago, Illinois and take place at the historic Hilton Chicago from August 25-30, 2024. The conference will be hosted jointly by Argonne National Laboratory and Fermi National Accelerator Laboratory.

LINAC is the main bi-yearly gathering for the world-wide community of linear accelerator experts. The conference will provide a unique opportunity to hear about the latest advances in research and developments on linacs and their applications.

Following a long and successful tradition, LINAC2024 will feature invited and contributed talks, as well as poster sessions and an industry exhibition. A stimulating scientific program will be complemented by social events that promote informal knowledge exchange. There are several sponsorship opportunities for all those who would like to support the event and gain visibility. LINAC2024 will be an in-person conference. Attendees will have the opportunity to participate in a special virtual tour of facilities at Argonne to see the newly commissioned Advanced Photon Source Upgrade as well as other accelerator facilities, and to view the progress of the Proton Improvement Plan II Superconducting radiofrequency linac and associated facilities at Fermilab.

LINAC encourages students and underrepresented communities to participate. There are a number of scholarships for students that will be offered. Early registration is now open and we encourage you to register early to secure a place.

Exhibitor and Sponsorship Prospectus.pdf

LINAC24-Student-Poster-Rubric.pdf

Sunday, 25 August

14:00 → 20:00 Registration

15:00 → 17:00 Student Poster Session

18:00 → 20:00 Welcome Reception

Monday, 26 August

08:30 → 09:15 Registration

09:15 → 10:30 Main Session MOX

09:15 Welcome

Speakers: John Byrd (Argonne National Laboratory), Sam Posen (Fermi National Accelerator Laboratory)

09:30 Recent advances in normal conducting radiofrequency linac structures

Normal conducting radiofrequency (NCRF) technology plays a crucial role in the development of more compact and cost-effective linear accelerators with increased energy reach and intensity. Over the past few years, NCRF structures have seen remarkable progress in accelerating gradient, RF-to-beam efficiency and overall performance that could lead to compact linacs for a multitude of applications. These advances are driven by new understanding of RF breakdown physics, innovative structure topologies and coupling schemes, advanced materials and fabrication techniques, and new operating regimes including operation at cryogenic temperatures, at various frequencies, and with nanosecond-scale RF pulses. In this talk, I will review some recent progress in NCRF structures and discuss their synergies with advanced accelerator concepts towards future colliders and compact light sources.

Speaker: Xueying Lu (Argonne National Laboratory)

10:00 The future of the Fermilab Accelerator Complex with the new PIP-II linac

In this opening plenary talk, the speaker will discuss advances in SRF technologies are enabling PIP-II, the new proton driver for the Fermilab Accelerator Complex currently under construction. This includes advanced cavity processing methods such as nitrogen doping and the mid-T bake and innovations in cryomodule design. He will present an overview of plans to evolve Complex in the PIP-II era to take advantage of the higher power beams from PIP-II to support the LBNF/DUNE neutrino program. Finally, he will discuss a vision for the future, including a proposed extension of the PIP-II linac, and how this can eventually enable a muon collider at Fermilab.

Speaker: Donato Passarelli (Fermi National Accelerator Laboratory)

10:30 → 11:00 Break

11:00 → 12:30 Main Session MOY

11:00 Breaking through 100 mA H- ion source output current at SNS

The SNS H- ion source performance has been improving over many years with main focus on increasing lifetime and availability. Recent R&D efforts achieved dramatic increase of output beam current in excess of 100mA. This talk will discuss the design improvements and diagnostics of the SNS H- ion source.

Speaker: Baoxi Han (Oak Ridge National Laboratory)

11:30 Coherent nanophotonic electron accelerator

The acceleration of electrons with the help of laser light inside a photonic nanostructure represents a microscopic alternative to microwave-driven accelerators. The main advantage is that the much higher driving facilitates damage thresholds of dielectric materials reaching 10 GV/m. This means that acceleration gradients far in excess of 1 GeV/m should be attainable. Furthermore, the structure size of the optical accelerators lies in the nanometer range, meaning that nanofabrication methods can be employed to build the accelerator structures. In pursuit of these goals, we demonstrated a scalable nanophotonic linear electron accelerator that coherently combines particle acceleration and transverse beam confinement utilizing an alternating phase focusing (APF) scheme. It accelerates and guides electrons over a considerable distance of 500 μm in a channel just 225 nm wide. The highest energy gain observed was 43%, from 28.4 keV to 40.7 keV. We expect this work to pave the way for nanophotonic accelerators. These on-chip particle accelerators might enable transformative applications in medicine, industry, materials research and science. In this talk, we will give a status update of nanophotonics accelerators.

Speaker: Prof. Julian Litzel

11:50 Operation of FLASH above 1.3 GeV and below 4 nm

FLASH is undergoing major modifications in the framework of the FLASH2020+ project.
During the last upgrade phase in 2021/22 alterations to the superconducting linac have been the main priorty. Among other changes two accelerating modules were replaced by modern high gradient versions. This allows to operate FLASH routinely with electron beam energies exceeding 1.3 GeV and thus extends the photon wavelength range to below 4 nm in the fundamental. This presentation summarises the major facility modifications during the 2021/22 shutdown and will give an overview and outlook about the operation since then.

Speaker: Lucas Schaper (Deutsches Elektronen-Synchrotron)

12:10 Current status of LWFA develpment towards robust table-top XUV-FEL

In order to develop a stable LWFA based accelerator and demonstrate FEL generation, the unique LWFA platform was constructed in the RIKEN SPring-8 center and systematic experiments have being conducted financially supported by ImPACT (2013-2018) and JST MIRAI (2018-) programs. Although undulator radiation in an XUV spectral range driven by LWFA electron beams was successfully demonstrated on the platform in 2019, the sufficient reproducibility was not obtained due to the poor electron pointing stability and large energy fluctuations. In order to solve the above problems, the accelerated electron beam quality has been improved by developing the Shock injection scheme enabling a precise injection control and a stable plasma condition. This development has dramatically improved the reproducibility and stability of the LWFA electron beam. The preliminary proof-of-concept experiment has recently demonstrated the clear amplification of the undulator radiation and the possibility of LWFA based FEL in XUV range. The talk will be presenting the outline of the LWFA platform, the setup of a proof-of-concept experiment focusing on key improvements and obtained results.

Speaker: Tomonao Hosokai (Osaka University)

12:30 → 14:00 Lunch

14:00 → 15:00 Main Session MOZ

14:00 High average gradient in a laser-gated multistage plasma wakefield accelerator

Plasma wakefield accelerators driven by particle beams are one promising method of advanced acceleration, with capable of providing accelerating gradient much larger than RF technology. One of the biggest remaining issues is coupling beams from one stage to another. This novel concept optimizes inter-plasma distances in a staged beam-driven plasma accelerator by drive-beam coupling in the temporal domain and gating the accelerator via a low-power, ultrashort pulse laser.

Speaker: Dr Alexander Knetsch (SLAC National Accelerator Laboratory)

14:20 State-of-the-art photocathodes for bright-beam and spin-polarized-beam generation

Talk will cover state-of-the-art photocathodes for bright-beam and spin-polarized-beam generation.

Speaker: Prof. Oksana Chubenko (Northern Illinois University)

14:40 Beam shaping using an ultra-high vacuum multileaf collimator and emittance exchange beamline

A multileaf collimator comprising many individually controlled blades has been used to impose predefined transverse beam shapes to an electron beam. Afterwards transverse-to-longitudinal mapping transforms this shape into a longitudinal one. This technique opens a wide field of applications using individually tailored longitudinal beam profiles.

Speaker: Dr Nathan Majernik (SLAC National Accelerator Laboratory)

15:00 → 16:00 Monday Oral Posters

16:00 → 18:00 Monday Poster Session

Tuesday, 27 August

08:30 → 10:30 Main Session TUX

08:30 Status of the Spallation Neutron Source Proton Power Upgrade

The Proton Power Upgrade (PPU) Project at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory will upgrade or replace accelerator components for beam power capability from 1.4 to 2.8 MW and upgrade the first target station for 2-MW beam at 1.3 GeV and at 60 pulses per second. The remaining beam power will be available for the future second target station. PPU scope is optimized between built-in upgrade provisions from the original SNS project, cost effectiveness and technical aspects based on SNS experiences. PPU is taking a phased approach for beam power ramp-up as new equipment are installed. This paper summarizes the status of PPU project, commissioning, progresses of beam power ramp-up and operation plan in the future.

Speaker: Sang-Ho Kim (Oak Ridge National Laboratory)

08:50 Installation and first commissioning of European Spallation Source (ESS) Linac

The European Spallation Source Linac is getting more and more ready. The drift tube linac has produced first beam, and the linac with its cryomodules and also warm units is taking shape. By LINAC 2024 first commissioning results can be expected. Beam on target is expected for 2025.

Speaker: Mats Lindroos (European Spallation Source ERIC)

09:10 Past, present and future studies, operation and performance of various heavy ion species in LINAC3

This talk will review the ions species tested and used in the heavy-ion source and linac3 for serving fixed target users but also the LHC and potential upgrades (ALICE3).

Speaker: Giulia Bellodi (European Organization for Nuclear Research)

09:30 First two years of FRIB operation

The Facility for Rare Isotope Beams (FRIB), a major nuclear physics facility for research with fast, stopped, and reaccelerated rare isotope beams, was successfully commissioned and has been in operation for the past two years. Various ion beam species have been accelerated up to 300 MeV/u and delivered to the target. FRIB routinely provided 10 kW primary beams on target over the past year, a factor of 10 above used at the beginning of user operation. Recently, a record-high 10.4 kW of uranium beam, the most challenging for accelerator systems, was delivered to the target, and three new isotopes were discovered during a short 24-hour run. In July 2024, we plan to develop a 20-kW Se-82 beam and provide it for the first observation of neutron-rich rare isotopes of calcium. Every incremental step in energy and power of primary beams allows us to gain valuable experience in the facility's safe operation and provides directions for further improvements. Several accelerator improvement projects are being pursued for further power ramp-up, improving the accelerator availability, delivering more time for science, and preparing for the ultimate 400 kW beam on target.

This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics and used resources of the FRIB Operations, which is a DOE Office of Science User Facility under Award Number DE-SC0023633.

Speaker: Peter Ostroumov (Facility for Rare Isotope Beams, Michigan State University)

09:50 Beam commissioning of Low Energy, High-Intensity Proton Accelerator (LEHIPA) at BARC

Bhabha Atomic Research Centre (BARC) has a long-term plan to develop a high energy (~ 1 GeV), high power (~ 10 MW cw) proton accelerator for Accelerator Driven System. With this endeavour, a pre-cursor project was conceived to develop a low energy (~ 20 MeV), high power (~200 kW) proton accelerator, utilizing 352.2 MHz RFQ accelerator, followed by four tanks of 352.2 MHz DTLs. Recently, beam commissioning experiments have been performed through RFQ and four tanks of DTL; and a beam energy of 20 MeV is achieved. Currently, pulsed operation of the accelerator (2 mA, 100 microsecond, 0.2 Hz) is demonstrated. The proposed speaker is expected to share the experience on design, fabrication and characterisation of individual modules, such as ion source, LEBT, RFQ, DTL and also beam diagnostics, along with stage-wise beam commissioning experience. For field stabilization and tuning of DTL, the recent technique developed at CERN has been used, which will also be of interest to the community. Problems faced during the beam commissioning, and its troubleshooting, along with use of innovative diagnostic techniques is also expected to be an important part of the talk, which will be of interest to the community. Finally, the proposed speaker is expected to share the future plans of accelerator development towards visualizing an accelerator for ADS.

Speaker: Dr Rajesh Kumar

10:10 CSNS linac energy upgrade

The CSNS power upgrade project (CSNS-II) has been launched. It will increase the proton beam power from 100 kW to 500 kW, along with the new construction of 9 neutron instruments. CSNS-II will utilize superconducting accelerator structures to raise the linac energy from 80 MeV to 300 MeV. The pre-research on key technologies has been completed. The newly developed RF ion source is already operational. Prototypes of the dual-spoke and 6-cell elliptical superconducting cavities and their corresponding cryomodules have been developed.

Speaker: Huachang Liu (Dongguan Neutron Science Center)

10:30 → 11:00 Break

11:00 → 12:30 Main Session TUY

12:30 → 14:00 Lunch

14:00 → 15:00 Main Session TUZ

14:00 Status and plans for the high-energy linear e+e- collider projects: ILC, CLIC and C3

The International Linear Collider (ILC), Compact Linear Collider (CLIC) and C3 are proposed designs for a next-generation high-energy electron-positron linear collider for exploring the Higgs-boson, top-quark and beyond-Standard Model sectors.
An overview and status of each collider project will be given, including the design, key technologies, accelerator systems, energy-staging strategies, and cost and power estimates, including sustainability considerations. An overview of the ongoing development strategy for each project over the next few years will also be given.

Speaker: Philip Burrows (John Adams Institute)

14:20 Fabrication and beam testing of a 180 GHz colinear wakefield accelerator

Corrugated waveguide based colinear wakefield accelerator development at Argonne National Laboratory has been ongoing, achieving significant progress in fabrication and testing of most principal components of the accelerator module. A few 30 cm long corrugated waveguides with a 2 mm ID and short transition sections which provide fundamental mode power extraction and beam offset diagnostics via the wakefield induced dipole mode have been fabricated. Several high field gradient quadrupoles envisioned for beam guidance and suppression of a beam breakup instability have been fabricated as well. The structures have been tested at mmWave frequencies and the quadrupoles were characterized via magnetic measurements. Electron beam testing was conducted at Brookhaven National Lab’s Accelerator Test Facility. The fundamental and dipole mode’s frequency and signal levels were measured and a good agreement with design parameters has been demonstrated.

Speaker: Branko Popovic (Argonne National Laboratory)

14:40 The Progress of CiADS linac and first beam acceleration

CiADS is the world’s first Accelerator Driven System under construction with a Mega-watt beam power. The linac of CiADS is designed to accelerate a 500 MeV and 5 mA proton beam with five-family superconducting resonators. The facility was lunched from mid 2021 and the hardware has finished the development of the prototype.  In this presentation, we will present the physical design of the superconducting linac, progress of key hardware and the first beam acceleration from normal conducting fronted.

Speaker: Zhijun Wang (Institute of Modern Physics, Chinese Academy of Sciences)

15:00 → 16:00 Tuesday Oral Posters

16:00 → 18:00 Tuesday Poster Session

Wednesday, 28 August

08:30 → 10:30 Main Session WEX

08:30 Status of the iBNCT accelerator

Present status and future prospects of the iBNCT accelerator will be discussed. Several accelerator-based neutron sources for Boron Neutron Capture Therapy (BNCT) have been developed in the world. The iBNCT (Ibaraki, BNCT) is a linac-based BNCT facility which is operated by University of Tsukuba and KEK in close collaboration with the local government, Ibaraki prefecture. The accelerator is based on the design and experiences of the J-PARC linac, and consists of an ion source, 3-MeV RFQ, 8-MeV DTL and a Beryllium target with modulators.

The project aims to realize a compact and low activation BNCT accelerator of several mA proton beam with high duty factor to obtain the thermal neutron flux required for BNCT, but with high stability as a medical accelerator.

Originally the cavities were designed with the minimum amount of cooling water, and their resonance frequencies were maintained by dynamical control of the water temperature according to the RF power input. However, after the interlock due to RFQ discharge, the resonance frequency was shifted frequently. By improving and enhancing the cooling water and vacuum, stable operation at an average current of 2 mA has been achieved. We are performing the pre-clinical testing in FY2022, and prepare to start clinical trials in FY2023. This reports the present status of the iBNCT accelerator and its future prospects.

Speaker: Masaharu Sato (High Energy Accelerator Research Organization)

08:50 Advances in fs-synchronisation

Linear accelerators for FELs have very high requirements for the accuracy of synchronization. The long and short term stability is influenced by various sources of interference. In this paper it will be shown which methods of stabilization exist and how synchronization accuracies up to the fs-level can be achieved.

Speaker: Marie Czwalinna (Deutsches Elektronen-Synchrotron)

09:10 Sub-femtosecond time-resolved measurements of electron and photon beams

Time-resolved diagnostics are fundamental for x-ray free-electron lasers (FELs). Radio-frequency (RF) transverse deflector structures (TDSs) are typically employed to characterize the temporal properties of the electron beams driving FELs. In this contribution, we present time-resolved measurements with a resolution below one femtosecond using a C-band and X-band RF TDS at SwissFEL. Measurements with a sub-femtosecond resolution are of crucial importance for ultra-fast x-ray FEL applications.

Speaker: Eduard Prat (Paul Scherrer Institut)

09:30 Full automatic clean assembly of HWR cavity

Unlike electron accelerators, hadron machines suffer from sever FE problem. High quality coldmass assembly in clean environment is the key assurance for high performance low beta cavities and cryomodules. However, low beta cavities like QWR, HWR or spoke cavities are much heavier and more difficult to assemble than elliptical cavities. IMP clean room team has introduced both clean-room-compatible and standard industrial robot to clean room assembly processes. Previous experience has shown that robots can significantly facilitate the assembly processes, reduce the re-work rate, and minimize the contamination risk. Currently, the team is working on the full-automated HWR cavity assembly process conducted by robots, AGVs and other automated devices. Without human presence in the clean room, it is expected that the assembled the HWR cavities have much lower FE doses compared with their peers.

Speaker: Hao Guo (Institute of Modern Physics, Chinese Academy of Sciences)

09:50 Adaptive machine learning with hard physics constraints for 6D phase space diagnostics

Machine learning (ML) tools have been growing in popularity for accelerator applications, but still struggle with time varying systems, for which they require lengthy brute-force re-training. LANL has developed machine learning (ML)-based tools, that utilize adaptive model independent feedback control theory together with hard physics constraints, to make the tools much more robust to distribution shift. These adaptive ML tools are able to extrapolate much further beyond the span of the training data and are thus much more robust for time-varying systems. This talk will give a broad overview of the challenges of various time-varying accelerator systems at various accelerator facilities (known as systems with distribution shift in the ML community) and will present adaptive ML tools for 6D phase space diagnostics of intense charged particle beams. The talk will also give a general overview of adaptive latent space tuning, which is the novel method we have developed for adaptive ML, and how we are strictly enforcing hard physics constraints in our ML tools, which traditional ML tools lack. We demonstrate our general methods for various accelerators: the 5-meter long ultra-fast electron diffraction (UED) HiRES compact accelerator at LBNL, the ~kilometer long plasma wakefield accelerator FACET-II at SLAC, and the LANL ion accelerator LANSCE.

Speaker: Alexander Scheinker (Los Alamos National Laboratory)

10:10 Crabbing cavity system development for International Linear Collider

The International Liner Collider requires a crabbing system to increase the luminosity of the colliding electron bunches. The ILC has a large crossing angle that requires compensation in order to meet the luminosity requirements. There are several frequency options proposed for the crabbing cavity design. Two crab cavity designs were selected to be prototyped in the pre-lab phase, following the Down Selection Review on Crab Cavity Design held in April 2023. The two rf designs selected are the 1.3 GHz rf-dipole cavity and the 2.6 GHz QMiR cavity. We will be presenting the electromagnetic and mechanical design details of the two compact crabbing cavity designs.

Speaker: Subashini De Silva (Old Dominion University)

10:30 → 11:00 Break

11:00 → 12:30 Main Session WEY

11:00 Distributed coupling linacs: a paradigm shift in linear accelerator design

Distributed coupling linear accelerators (DCLs) represent a revolutionary approach to accelerator design, offering significant advantages over traditional standing-wave and traveling-wave linacs. DCLs achieve record-breaking efficiency and gradient while remaining highly reliable, even under extreme operating conditions. These advancements make them ideal for a wide range of applications, including: Novel FELs, C3 collider concepts, medical radiotherapy, and Inspection and imaging technologies. This presentation delves into the theoretical underpinnings of DCLs and their latest development. We will explore how the technology has evolved from its initial pi-mode configuration to the even more efficient 3 pi/4-mode structure.

Speaker: Sami Tantawi (SLAC National Accelerator Laboratory)

11:30 The Deep Electron FLASH Therapy facility

The DEFT facility at the university hospital of Lausanne (CHUV) is based on a CERN accelerator design, which will be produced and installed by industry (THERYQ). This talk describes the machine design, the collaborative set-up and the planning towards completion.

Speaker: Carlo Rossi (European Organization for Nuclear Research)

11:50 PIP-II: an international endeavor to enable neutrino science

This talk will provide an overview of the PIP-II project, how the international contributions are being arranged, the major systems, current status, and outlook. It will also discuss how the accelerator complex will be evolved to take advantage of PIP-II beams to meet the needs of the neutrino program, including some of the accelerator physics challenges.

Speaker: Dr Pantaleo Raimondi

12:10 Results from CXLS commissioning

The Compact X-ray Light Source (CXLS) is a compact source of femtosecond pulses of x-rays that is now commissioning in the hard x-ray energy range 4-20 keV. It collides the beams from recently developed X-band distributed-coupling, room-temperature, standing-wave linacs and photoinjectors operating at 1 kHz repetition rates and 9300 MHz RF frequency, and recently developed Yb-based lasers operating at high peak and average power to produce fs pulses of 1030 nm light at 1 kHz repetition rate with pulse energy up to 200 mJ. These instruments are designed to drive a user program in time-resolved x-ray studies such as SAXS/WAXS, XES and XAS, femtosecond crystallography as well as imaging. The different technical systems also act as prototypes for the more advanced CXFEL discussed elsewhere in these proceedings. We present the performance of the CXLS technical components and initial x-ray results.

Speaker: William Graves (Arizona State University)

12:30 → 17:00 Outing

Thursday, 29 August

08:30 → 10:30 Main Session THX

08:30 Cavity failure compensation strategies in superconducting linacs

Reliability is an important feature for high power particle accelerators. This is particularly true for Accelerator-Driven Systems (ADS), for that every beam interruption can strongly affect the availability of the nuclear reactor.

Many of these outages come from the loss of accelerating cavities or of their associated systems. Cavity failures can be compensated for by retuning other cavities of the linac. Finding the ideal compensation settings is however a difficult challenge that involves beam dynamics and multi-objective optimisation, and which raises very different issues according to the linac under study. For instance in the SPIRAL2 linac, a lot of cavities are mobilized for the compensation and the search space has a very high number of dimensions. Plus, it has quite low margins on the longitudinal acceptance. Linacs for ADS (such as the Japan Atomic Energy Agency ADS or MYRRHA) have a specific fault-tolerance design which facilitate the optimisation, but cavities have to be retuned in a few seconds.

Hence we developed LightWin, a tool to automatically and systematically find compensation settings for every cavity failure of any given linac. In this study, we will present LightWin’s latest developments as well as the compensation strategies that we developed for SPIRAL2 and ADS linacs, both from a beam dynamics and a mathematical point of view.

Speaker: Dr Adrien Plaçais (Laboratoire de Physique Subatomique et de Cosmologie)

09:10 Matched transport of intense and coasting beams through quadrupole channels

For the time being, determining the cell-to-cell periodic solution for transporting intense beams has been limited to the spatial envelope. Recently, a numerical method for provision of full 4d-periodicity of all 10 beam moments of an intense 4d-coupled beam has been developed and benchmarked with tracking simulations. For instance, it will pave the path towards exploring the potential of beam spinning for beam quality improvement as proposed by Y.-L. Cheon et al.

Speaker: Chen Xiao (GSI Helmholtzzentrum für Schwerionenforschung GmbH)

09:30 Machine-learning-assisted beam tuning at FRIB

Proposed Abstract: FRIB requires many primary ion species for production of rare isotopes. The beam development time can be significantly reduced by employing surrogate or policy (control) model-based optimization techniques. Sophisticated methodologies continuously evolve within accelerator communities to elevate the performance of beam tuning techniques. In this talk, we aim to explore practical perspectives on shortening beam tuning time to provide more time for science. Specifically, we discuss the development of portable and widely applicable objective (loss) function construction tailored for beam tuning. Furthermore, we present machine-learning-assisted beam tuning methods that we have pioneered to elevate the linac performance in practice.

Speaker: Kilean Hwang (Facility for Rare Isotope Beams)

09:50 An overview of plasma processing of SRF cavities at JLAB

Plasma processing is a common technique where the free oxygen produced in a low-pressure RF plasma breaks down and removes hydrocarbons from surfaces. This increases the work function and reduces the secondary emission coefficient of the treated surfaces. Jefferson Lab has an ongoing R&D program in plasma processing. The experimental program investigated processing using argon/oxygen and helium/oxygen gas mixtures. The initial focus of the effort was processing C100 cavities by injecting RF power into the HOM coupler ports. We also developed the methods for establishing a plasma C75 cavities where the RF power is injected via the fundamental power-coupler. As part of the process development we processed, three C100 cryomodules in our off-line cryomodule test facility. In May 2023 we processed four C100 cryomodules in-situ in the CEBAF accelerator with the cryomodules returning to an operational status in Sept. 2023. The improvement in field emission free operation, as measured on a cavity by cavity basis, was 59 MeV or 24%. At the time that this abstract was written, the plans are to process an additional 5 to 7 cryomodules in the CEBAF accelerator in the summer of 2024. Methods systems and results from processing cryomodules and individual cavities in the vertical test will be presented. Current status and future plans will also be presented.
Funding provided by SC Nuclear Physics Program through DOE SC Lab funding announcement DE-FOA-0002670.

Speaker: Tom Powers (Thomas Jefferson National Accelerator Facility)

10:10 Wide dynamic range diagnostics system for primary and secondary beams at FRIB

The FRIB diagnostics system covers an extensive range of primary and secondary beam intensities of 14 orders of magnitude and requires continuous improvements. The linac diagnostic system has provided straightforward linac commissioning and supports the development of many primary heavy ion beam species for producing rare isotopes. The diagnostics system for the secondary beam has a unique feature of detecting and measuring low-intensity rare isotope beams. This talk will report on the performance of the FRIB diagnostics system and ongoing improvements.

Speaker: Steven Lidia (Facility for Rare Isotope Beams, Michigan State University)

10:30 → 11:00 Break

11:00 → 12:30 Main Session THY

11:00 Commissioning of the RAON superconducting linac

Argon beam was successfully accelerated in the RAON low energy superconducting linac in May, 2023. Neon and oxygen beams are to be accelerated in 2024 providing beam for the experiment systems.

Speaker: Ji-Ho Jang (Institute for Basic Science)

11:30 Design of ultrafast electron microscopy with superconducting rf gun

Observation of ultrafast structural dynamics is very important for elucidating functions and creating new materials. We have been promoting research and development of ultrafast electron microscopes by generating relativistic femtosecond electron beam pulses using radio frequency (RF) accelerator technology. So far, we have fabricated the world's first ultrafast electron microscope using a normal-conducting S-band RF electron gun and demonstrated its feasibility in demonstration experiments. However, the normal-conducting RF electron gun uses high-power RF pulses, which causes limitations of low beam repetition rate and pulse-by-pulse energy stability. In this study, we have devised an L-band Nb3Sn superconducting RF electron gun that breaks through these limitations and are aiming to develop an ultrafast electron microscope using this gun. We will report the design of the Nb3Sn superconducting RF electron gun, beam simulation results, and conceptual design of an ultrafast electron microscope using the gun.

Speaker: Jinfeng Yang (Osaka University)

11:50 High charge, 10-GeV electron bunches from a 10-cm long, nanoparticle assisted, laser wakefield accelerator: our next steps

We recently demonstrated generation of very high charge (1+ nC), very high energy (10 GeV) electron bunches from a nanoparticle-assisted laser wakefield accelerator [1]. While the experiment did yield record breaking results, the statistics were quite poor due to the very slow repetition rate of the Texas Petawatt Laser system. We are currently on a campaign to repeat and improve upon these results. Here we will report on our improved understanding of the nanoparticle-assist effect as well as the planned experimental program we have laid out.

[1] C. Aniculaesei et al. “The Acceleration of a High-Charge Electron Bunch to 10 GeV in a 10-cm Nanoparticle-Assisted Wakefield Accelerator”, Matter Radiat. Extremes 9, 014001 (2024) https://doi.org/10.1063/5.0161687

Speaker: Stephen Milton (TAU Systems, Inc.)

12:30 → 14:00 Lunch

14:00 → 15:00 Main Session THZ

14:00 Commissioning of LCLS-II

We will present the results of the commissioning program to establish x-ray lasing and operation of the LCLS-II facility, based on the 4 GeV superconducting accelerator. The commissioning scope included the cryogenic systems, SRF and cryomodules, beam transport and two undulator beamlines serving the hard and soft x-ray programs. The talk will include a discussion of achieved beam performance, both for electron and photon beam and our plans to ramp up to the final objectives. A report of operational issues will be included as well. Finally a brief summary of the status of LCLS-II-HE will be provided.

Speaker: Axel Brachmann (SLAC National Accelerator Laboratory)

14:20 Various applications of SRF linear accelerators in KEK

As an introduction, we will talk about the merit of the superconducting cavity and we about our applied research based on Compact ERL (cERL) in KEK, which uses the Nb superconducting cavity and can make energy recovery operation. The cERL’s characteristic using the high-current beam has a variety of applications; industrial applications using high-intensity terahertz light and mid-infrared FEL (free-electron laser). In addition, high current CW-beam irradiation was conducted for basic research on domestic production of nuclear medicine, strengthening of asphalt, and the highly efficient production of nanocellulose from wood in cERL. After talking about these applications of cERL, we will discuss “Future plan for applied research using superconducting accelerators”. One is the EUV-FEL light source development for EUV-lithography and the other is the development of compact superconducting RF accelerator based on Nb3Sn for high-power beam irradiation.

Speaker: Hiroshi Sakai (High Energy Accelerator Research Organization)

15:00 → 16:00 Thursday Oral Posters

16:00 → 18:00 Thursday Poster Session

19:00 → 23:00 Conference Dinner

Friday, 30 August

08:30 → 10:30 Main Session FRX

08:30 R&D on laser plasma based accelerators in India

R&D on laser plasma based accelerators started in India only in the beginning of this century. Both experimental and theoretical studies on laser plasma interaction have been performed at various national labs and universities. High-power Nd:Glass laser systems were developed at RRCAT, Indore. In 2006, a CPA-based 10 TW Ti:Sapphire laser system was set up at RRCAT, for laser plasma interaction studies in the ultrashort, ultra-intense regime. This was followed with a 150 TW laser system, and currently installation of a 1 PW Ti:Sapphire laser system has been completed. Extensive investigations on LPA have been done at RRCAT. In initial experiments, using high-power (10-150 TW), ultra-fast (25-50 fs) Ti: sapphire lasers, interacting with 1.2 mm of plasma length, acceleration of electrons from 25 MeV to over 100 MeV has been achieved. Recently, using longer gas-jet plasma of 4 mm length, acceleration of electron beams in the energy range of ~ 200 MeV to over 500 MeV has been demonstrated. The proposed speaker will give start with historical overview of R&D efforts in this field in India, and will share the latest results. The proposed speaker is expected to present a summary of physics studies done in this area to enhance the understanding of laser plasma acceleration, and will present a future plan in the country in this area of R&D.

Speaker: Prof. Anand Moorti (Raja Ramanna Centre for Advanced Technology)

08:50 Machine learning-based fault classification in superconducting cavities at Chinese ADS front-end demo SRF linac

In 2021, the Chinese ADS Front-end demo superconducting radio-frequency (SRF) linac, known as CAFe, successfully conducted a commissioning of a 10 mA, 200 kW continuous wave proton beam. During this commissioning, it was observed that the SRF cavity fault played a predominant role, contributing to approximately 70% of total beam trips. Upon the detection of fault signals, an acquisition process recorded 8 RF waveforms using digital low-level radio-frequency systems. A meticulous study of the cavity fault mechanisms was undertaken, leading to the identification and generalization of several fault patterns through the analysis of collected time-series data. The findings revealed that the dominant causes of SRF trips were field emission-triggered cavity faults and thermal quenches. We optimized the feature extraction methods for fault signals and developed a machine learning-based fault classification model. Comparative analysis with expert identification results demonstrated an accuracy rate of over 90% for the model. This research marks a significant stride towards enhancing the availability and reliability of operational beams for the future China Initiative Accelerator-Driven System project.

Speaker: Feng Qiu (Institute of Modern Physics, Chinese Academy of Sciences)

09:10 SRF coaxial resonators for hadron acceleration

SRF technology using niobium accelerating cavities enables high performance and efficient acceleration for modern accelerator projects. While electron linacs accelerate particles with common structures designed for relativistic acceleration hadron linacs require acceleration over a broad velocity range. SRF technology is now being adopted at hadron energies in some cases starting from the RFQ exit but with top end energies such that a velocity range of a factor of ten has to be considered in the linac configuration and cavity design. Different structures in the TEM mode (coaxial) class (QWR, HWR, SSR, DSR) are employed with customized rf frequency, design beta and cavity structure. The coaxial cavities are now operating at very high performance rivaling the achievements in the 1.3GHz elliptical cavities. The talk should give an overview of the state of the art in the field.

Speaker: Philipp Kolb (TRIUMF)

09:30 Operational experience and reliability of the new CERN Linac4

Since its completion in 2017, the new 160 MeV injector for the CERN accelerator complex Linac4 has undergone some tests to assess and improve reliability, until being connected to the Booster ring during the 2018-22 LHC shutdown. The performance requirements for the LHC high-luminosity upgrade have been successfully met, and during its first two complete years of operation the new accelerator has shown remarkable reliability figures. Recent improvements of the H- ion source are making possible a further increase in the current, for the benefit of the experimental programmes using the Booster beams.

Speaker: Edgar Sargsyan (European Organization for Nuclear Research)

09:50 Status of HIAF iLinac SC cavity system at IMP

HIAF is a heavy ion accelerator facility in China for nuclear physics research. The superconducting LINAC was used to accelerating beam energy up to 17MeV/u, then injecting to a Booster Ring. The linac are under construction since 2021, which includes 30 quarter-wave resonator (QWR) and 66 half-wave resonator (HWR). The first-batch production of cavity system have been completed. And the cavity's auxiliaries, such as coupler and tuner are ready too for first two cryomodules. This paper will present the current status of the HIAF SC cavity system.

Speaker: Mengxin Xu (Institute of Modern Physics, Chinese Academy of Sciences)

10:10 Using an electron linac to improve the sustainability of diamond mining

We report on the successful test for locating diamonds in ore by using an electron linac to create the 11C isotope atoms via the (gamma,n) reaction which has a large cross-section (8mb) at the Giant Dipole Resonance. The 11C atoms can be detected consequently using the Positron Emission Tomography (PET).

The technology is presently being scaled up for deployment in a mine with the goal of discovery diamonds in the kimberlite ore grade. The typical run-of-mine throughput of several hundred tons per hour requires a high-power electron linac paired with high rate-capacity PET detectors system. 100% concentrate can be achieved followed by an intelligent diamond recovery process. Besides reducing breakage, the technology is waterless and greener. The mine lifetime will be extended, and marginal mines become viable.

The design of the linac has converged to Ee = 45MeV at 200 kW in the beam. Ruggedness in the mining environment dictates a warm Cu, S-band machine. The system can produce the required PET activity of 2 kBq/cm3 measured after a 30 min decay out of a FIFO storage to leave 11C as the dominant PET isotope. The technology is termed MinPET and is currently under study. This contribution details the linac design component of the project.

Speaker: Benjamin Bromberger (RI Research Instruments GmbH)

10:30 → 11:00 Break

11:00 → 12:30 Main Session FRY

11:00 The quest for high gradient and high Q in SRF cavities

The SRF world has made considerable advances in the last 15 years on the performance of bulk niobium cavities. Processing recipes like N-doping and 120C baking are now being accepted as standard and consistently delivered by industry. New treatments like mid-T baking are now being incorporated into some project processing recipes as well. Thin film research is advancing with the mission to pave the way to performance beyond bulk niobium. This talk should give a summary of present performance with a glimpse towards the fundamental processes at play in the treatments of today and some thoughts towards future directions.

Speaker: Akira Miyazaki (Université Paris-Saclay, CNRS/IN2P3, IJCLab)

11:30 Light sources for the semiconductor industry

Industrial applications of accelerators will be discussed.

Speaker: Erik Hosler (Globalfoundries)

12:00 TBA

Title TBA

Speaker: Stephen Streiffer (Oak Ridge National Laboratory)

13:00 → 15:00 Laboratory Virtual Tour