Snowmass’21 Workshop on High-Power Cyclotrons/FFAs

7 Sep 2021, 09:00 → 9 Sep 2021, 12:00 America/New_York

Zoom

Andreas Adelmann (PSI/ETHZ), Daniel Winklehner (Massachusetts Institute of Technology), Hiroki Okuno (RIKEN), Jose Alonso (LBNL), Luciano Calabretta (INFN-LNL)

Update: Please find the report of this workshop here: Workshop Report

It is our pleasure to announce the Workshop on High-Power Cyclotrons/FFAs to be held as part of the US Snowmass’21 process. This will be a three-day, virtual workshop to summarize the state-of-the-art in high power cyclotrons and FFAs and discuss future (needed) development.

The workshop will be held entirely on Zoom. Due to the crossing of multiple time-zones, we will only officially meet for three hours per day, but will keep the Zoom rooms open for breakout discussions 24/7. We will have two hours of oral contributions each day, followed by a one-hour panel discussion, moderated by the day’s session conveners.

We invite you to submit a title and (brief) abstract for consideration for the plenary sessions through this website. All contributions will be consolidated into an arXiv whitepaper, edited by the session conveners and the organizing committee.

Please also let Daniel Winklehner know if you would like to convene a session.

We are looking forward to interesting contributions and fruitful discussions!

Yours sincerely,
    Andreas Adelmann (PSI, ETHZ)
    Jose Alonso (LBNL, MIT)
    Luciano Calabretta (INFN-LNL)
    Hiroki Okuno (RIKEN)
    Daniel Winklehner (MIT), Chair

    (The Organizing Committee)

Tuesday, 7 September

09:00 → 10:00 Current state of the art in high power cyclotrons/FFAs: Existing Cyclotrons/FFAs

09:00 Welcome Remarks

Speaker: Daniel Winklehner (Massachusetts Institute of Technology)

Workshop on High Power Cyclotrons - Welcome Remarks.pdf

09:05 TRIUMF Cyclotron Current Limit

H$^-$ cyclotrons, such are TRIUMF 500 MeV machine, are essentially characterized by their large phase acceptance. Since beam extraction relies on charge exchange (H$^-$ to H$^+$) no turn separation is required. Bunches typically occupy several tens of degrees of rf phase, and consequently acquire, during the acceleration process, a large energy spread. This large energy spread leads neighboring bunches to overlap, making the charge distribution withing the cyclotron resemble a quasi-continuous ``slice'' of charge.
The dynamics of this charge distribution, in the presence of space charge forces, is the subject of this study. After a brief historical overview of the topic, we will consider the problem of numerically calculating the steady state of the charge distribution. We show how this problem can be solve with modest computational resources by making the assumption that the shape of a given bunch evolves slowly compared to the revolution period. We present simulation results, with application to the case of TRIUMF 500 MeV cyclotron. We also present benchmark test results against both experimental data and simulations using the computer code OPAL-CYC.

Speaker: Thomas Planche (TRIUMF)

TRIUMF Cyclotron(s) Current Limit

09:25 Operational experience with the RIKEN RIBF accelerator complex

The RIKEN RI Beam Factory (RIBF) is the world's most intense heavy ion accelerator facility based on cyclotrons. We have been operating this facility for 16 years with increasing intensity especially of very heavy ions such as uranium ion. I will report operational experience with the cyclotrons, including problems, failure, and reliability.

Speaker: Hiroki Okuno

210816 Snowmass Cyclotron WS talk okuno.pdf

09:40 A 70 MeV cyclotron facility of IBS for ISOL and other uses

A 70-MeV proton cyclotron system (C70) will be installed this year in the ISOL building of Institute for Basic Science, Korea. We made a contract with IBA in June 2019, and the contract will end with site acceptance tests in the middle of 2022. Currently, one beam line is prepared for ISOL target while two target bunkers are constructed. In addition, some area is available for different beam uses. The status of the project and user perspectives will be presented.

Speaker: Jongwon Kim (Institute for Basic Science)

Snowmass workshop-JW Kim IBS-Sep 2021.pdf

10:00 → 11:00 Current state of the art in high power cyclotrons/FFAs: Limitations of existing Cyclotrons/FFAs

10:00 The High Intensity Proton Accelerator Facility at PSI. Past, Present, Projects.

The High Intensity Proton Accelerator Facility at PSI routinely produces a 590 MeV proton beam with currents of up to 2.4 mA.
The 1.4 MW beam is used to generate neutrons in spallation targets, and pions in meson production targets. The secondary particles are used for condensed matter and particle physics research at the intensity frontier. This presentation will give an overview of the facility and cover aspects of its performance, availability as well as energy efficiency. The control of beam losses, intensity limits, and further upgrades will be addressed.

Speaker: Joachim Grillenberger (Paul Scherrer Institute)

Snowmass21_GJ.pdf

10:20 Major limitations of fixed field particle accelerators

While the best known utilizations of particle accelerators are associated with high-energy physics, a growing number of applications such as heavy ion therapy, energy amplifiers and neutrino factory rather rely on producing high intensity charged particles. For instance, cyclotrons existed since the 1950s and demonstrated their capability to achieve such high intensity beams. Nevertheless, in the recent years, several new concepts of fixed field accelerators have emerged as an attempt to overcome some of the limitations of cyclotrons.
This talk reviews several considerations on the design of fixed field accelerators and discusses the main practical limitations/imperfections of existing machines to reaching a reliable operation with the highest possible currents

Speaker: Malek Haj Tahar (Paul Scherrer Institut)

Snowmass_MHT_07_09_21.pptx

10:40 Current Limits of (PSI’s) High Power Cyclotrons: Theory and Practice

The PSI HIPA cyclotron facility is described and some considerations on maximal continuous beam intensity and related issues are given.

Speaker: Christian Baumgarten (Paul Scherrer Institut)

snowmass2021_baumgarten.pdf

11:00 → 12:00 Current state of the art in high power cyclotrons/FFAs: Panel Discussion

Wednesday, 8 September

09:00 → 09:40 Applications of high power cyclotrons/FFAs: Isotope Production

09:00 Production of radioisotopes for application studies at RIKEN RI Beam Factory

At RIKEN RI Beam Factory (RIBF), Wako, Japan, we have been developing production technologies of radioisotopes (RIs) and conducting RI application studies in the fields of physics, chemistry, biology, engineering, medicine, pharmaceutical and environmental sciences. With light- to heavy-ion beams from the AVF cyclotron, we produce more than 100 RIs from 7Be to 262Db. RIs of a large number of elements (multitracer) are simultaneously produced from metallic targets such as natAg, 197Au, and 232Th irradiated with a 135-MeV nucl.–1 14N beam from RIKEN Ring Cyclotron. The multitracer is useful to trace the behavior of many elements simultaneously under an identical experimental condition. We installed a gas-jet transport system on the gas-filled recoil ion separator GARIS at the RIKEN heavy-ion linear accelerator. 261Rf, 262Db, 265Sg, and 266Bh are produced for chemistry studies in the heavy-ion induced reactions on a 248Cm target.

Speaker: Hiromitsu Haba (RIKEN)

210903 Snowmass’21 Workshop on High Power Cyclotrons Haba (open).pptx

09:20 Isotope Production at UAB

Speaker: Suzanne Lapi (University of Alabama at Birmingham)

Lapi Snowmass 2021.pdf

09:30 Radionuclide Production at TRIUMF: The Institute for Advanced Medical Isotopes (IAMI), The Future is Now.

IAMI encompasses the multiple accelerator systems at TRIUMF with international expertise in the application of radioactivity in basic and applied research.

The accelerators include protons and electrons from 13 MeV to 500 MeV, all with high beam currents.

The IAMI team will focus on the merging field of Theranostics, bringing the imaging capabilities to the treatment of disease under the same umbrella.

Speaker: Thomas Ruth (TRIUMF)

202109 Ruth + Schaffer Snowmass-Final.pdf

09:40 → 10:20 Applications of high power cyclotrons/FFAs: New Physics

09:40 An application of high power cyclotrons in physics: IsoDAR

This talk will present a number of physics opportunities associated with a 60 MeV/amu cyclotron, using the IsoDAR experiment as an example.

Speaker: Josh Spitz (University of Michigan)

snowmass_cyclotrons_spitz.pdf

10:00 The search for µ→eee and what it may need beyond Mu3e phase II

The Mu3e collaboration is currently constructing the phase I experimental setup at the Paul Scherrer Institut (PSI) over the next two years. A very successful prototype run confirmed the technical concepts being feasible. This setup will reach an unprecedented sensitivity for an upper limit of $BR(\mu\rightarrow e e e) < 10^{-15}$ using a stopping rate of $10^8 \mu^+/s$ on the target. The following phase II experiment will make use of an improved detector design and the increased muon rate at the prospective Hight Intensity Muon Beamline at PSI, ultimately reaching $< 10^{-16}$ using $10^9 \mu^+/s$ stopping on the target. Beyond that, even higher intensities will be needed.
This talk will give an overview of the Mu3e experiment, the detector concepts (with remarks on how they would perform at higher mmuon stopping rates), its current status and the plans for the future.

Speaker: Frank Meier Aeschbacher (PSI - Paul Scherrer Institut, Switzerland)

praesMu3eSnowmass210908.pdf

10:15 Break

10:20 → 11:00 Applications of high power cyclotrons/FFAs: Accelerator Driven Systems

10:20 Megawatt Class Beams From Fixed-Field Rings For ADS-Reactor Application

This short talk will underline beam requirements for ADS-R application; foreseeable accelerator options to achieve these, and today's landscape; challenges to overcome; areas of R&D.

Speaker: Francois Meot (BNL)

slides_snowmass21_PSI_Sept2021.pdf

10:35 ADS Prospects and Requirements

A brief review of the present status and future possible developments for Accelerator Driven Reactors, of the requirements for the accelerator, and whether these can be met by a cyclotron or an FFA.

Speaker: Roger Barlow (Huddersfield)

3.mp4

3.pdf

10:50 Limits of the present cyclotron projects and future perspectives for ADS.

A review of the High power cyclotron projects proposed to drive ADS is shortly present.
Their advantages and limits as drivers for ADS are discussed. The possible technical solutions and/or research needs to overcome these limits are also discussed.

Speaker: Luciano Calabretta (INFN)

Limits of the present cyclotron projects and future perspectives for ADS.pdf

11:00 → 12:00 Applications of high power cyclotrons/FFAs: Panel Discussion

Thursday, 9 September

09:00 → 10:00 Novel concepts for high power cyclotrons/FFAs: Design/Hardware

09:00 Development of vertical excursion FFA

We are developing a vertical excursion FFA (vFFA) for a proton driver of a future spallation neutron source. vFFA could be made with small footprint than cyclotrons or conventional FFAs. Coupled optics may (or may not) help high intensity operation. We will present the status of vFFA design study at RAL.

Speaker: Jean-Baptiste Lagrange (STFC-UKRI)

210909_vffa_lagrange.pdf

09:20 INNOVATRON: AN INNOVATIVE INDUSTRIAL HIGH-INTENSITY CYCLOTRON FOR PRODUCTION OF MEDICAL RADIOISOTOPES

A research project is ongoing at IBA to design an innovative compact high-intensity self-extracting cyclotron. The project, named InnovaTron, has received funding from the EU H2020 MSCA programme. In the self-extracting cyclotron, proton beams are extracted without any active device. A prototype cyclotron was built by IBA in 2001. Proton currents up to 2 mA were extracted from it. InnovaTron will improve the magnet design and the beam optics of the self-extracting cyclotron for the acceleration of high-intensity proton beams up to 5 mA or more to be used for large-scale industrial applications. An overview on the InnovaTron project will be presented together with the first simulation results, including space charge.

Speaker: Grazia D'Agostino (IBA)

Snowmass21_InnovaTron.pdf

09:30 The RFQ Direct Injection System for the IsoDAR cyclotron

The IsoDAR project is a neutrino experiment that re-quires a high current molecular hydrogen beam at 60 MeV/amu, which will be produced by a cyclotron. A critical aspect of the design is the injection, which comprises an ion source, a compact low energy beam transport section (LEBT), and a radio-frequency quadrupole (RFQ) buncher embedded in the cyclotron yoke. The LEBT is optimized to match the desired input Twiss parameters of the RFQ. Here we report on the design for the full RFQ system.

Speaker: Loyd Waites (student@mit.edu)

Isodar_workshop_8_2021.pptx

09:40 Spiral Inflectors for High Power Cyclotrons

A recent trend in spiral inflector design is the use of transverse electric field gradients in order to influence the optics. These methods can improve the vertical focusing of the inflector and prevent longitudinal de-bunching, increasing the cyclotron transmission. Permanent magnet spiral inflectors offer a possible alternative for fixed-energy machines.

Speaker: Hugo Barnard (iThemba LABS)

Hugo Barnard - Spiral Inflector.pptx

09:50 Feasibility study for the cylindrically symmetric magnetic inflector

For the conventional electrostatic inflector, one of the limitation for the injection energy is the breakdown voltage between the 2 electrodes. To ensure the uniformity of the electric field, the aperture in a spiral inflector is small, which would also limits the injection intensity. To achieve high energy and high intensity injection. The magnetic inflector is a promising solution. In this report, we study a novel injection method cyclotron based on an original proposal from W. Kleeven. The cyclotron magnet model we used to study the injection is the TRIUMF TR100 cyclotron conceptual model.

Speaker: Lige Zhang

Snowmass_21_Lige_Zhang.pdf

10:00 → 11:00 Novel concepts for high power cyclotrons/FFAs: Computation/Simulation

10:00 Use of a map approach for tracking in FFAs

Typically FFAs are tracked by numerical integration of the equations of motion through the fields, for example using Runge Kutta integration steps. Collective effects are applied at integration steps in the usual way. However, ideal FFAs are an excellent candidate for using a transfer map approach to tracking - transport is, by construction, entirely independent of particle momentum so that a transfer map can be integrated for a single cell of the machine at a single momentum and then applied for all cells, given a suitable momentum scaling. In this presentation, the Hamiltonian expansion for FFAs is derived, including appropriate scaling fringe fields, and shown to be momentum independent at all orders. The route to calculation of transfer maps is discussed and approaches to including collective effects are considered.

Speaker: Chris Rogers (ISIS)

2021-09-09_rogers-ffa-snowmass.pdf

10:20 Development of the simulation code OPAL

The use of numerical models for beam dynamics studies is an essential step in the design process of particle accelerators. These studies demand precise simulation tools describing the movement of the particles subjected to external fields and the interactions with other particles, either within the beam or between the beam and the wall. All these present modeling challenges. Many computer models have been developed for this purpose, some of them with particular attention to cyclotron-like accelerators: Classical and Isochronous Cyclotrons, Synchrocyclotrons, and Fixed Field Alternating Gradient (FFA) machines. OPAL (Object-Oriented Parallel Accelerator Library), an open-source Particle-In-Cell (PIC) code developed for large-scale charged-particle optics simulations in accelerators and beam lines, is one of the most complete and versatile codes. In this talk, I aim to present a general introduction of OPAL, followed by the new features available in the last release version. I will also discuss plans within the developer workflow and comments addressing the challenges ahead, like more precise modeling needs and the new exascale computing facilities.

Speaker: Pedro Calvo (CIEMAT)

OPAL_presentation_Snowmass21_PedroCalvo.pdf

10:40 TRIUMF Simulation Tools Status & Future

TRIUMF hosts several high-power accelerators -- including the 500 MeV cyclotron and the 30 MeV electron linac --, a variety of primary and secondary beamlines, and rare ion beams post accelerators. The computer programs that we use to simulate the beam dynamics in these machines can be grouped into two categories, depending on whether they use a 'detailed' or a 'reduced' beam physics model. Under the 'detailed' category we make extensive use of the particle-in-cell codes ASTRA, OPAL-CYC, and WARP.
But the work-horse of beam physics at TRIUMF is the 'reduced' code TRANSOPTR, which instead of calculating the trajectories of a large number of macro-particles, tracks directly the 21 statistical second moments of the beam distribution. I will present a brief overview of this code, and show examples of applications.
In many high intensity cases, a purely second-moment code such as TRANSOPTR is incapable of giving the detail needed to predict and control losses. For these more complicated cases, where 'detailed codes' work but are orders of magnitude slower to run, we are developing hybrid models, which combines features of both 'reduced' and 'detailed' models. We recently successfully implemented and tested such a code, which represents the beam using macro-particles containing discrete longitudinal coordinates but transverse second moments. I will explain this approach in detail, and discuss our plans to continue developing such codes that can be tuned to track exactly the physics one is interested in, and no more than that, achieving optimum computer efficiency and execution speed.
I will also touch upon the topics of the symplecticity of such codes.

Speaker: Thomas Planche (TRIUMF)

TRIUMF Simulation Tools Status & Future

11:00 → 12:00 Novel concepts for high power cyclotrons/FFAs: Panel discussion