Tuesday, January 28, 2020 at 4:00 pm

Speaker: Yichen Ji, IIT

Title:E-cloud study at Fermilab

Abstract:

The electron cloud (E-cloud) can potentially cause operational problems in accelerators all around the world. There are planned beam intensity increases due to upgrades of the Fermilab accelerator complex, so E-cloud could become a problem. This research took several approaches toward understanding the risk of E-cloud at Fermilab. The evolution of the SEY of the SS316L (stainless steel), TiN coated SS316L, and amorphous carbon coated SS316L were measured in-situ using a Secondary Electron Yield coefficient (SEY) measurement test stand in the MI tunnel. Direct measurements of the electron cloud were done as well, and compared to simulation. The electron cloud bombardment rate was measured at different beam intensities and bunch lengths. The Retarding Field Analyzer (RFA) measuring the electron cloud bombardment rate was near the instrument that is used to measure the SEY of the beam pipe material. This proximity provided an accurate SEY value for simulations, so that the simulated electron cloud bombardment rate could be better compared to measurement. The POSINST simulations of electron cloud were a good match to direct measurements. This gave confidence that predictions could be made concerning the E-cloud densities at upgrade intensities. These densities were compared against corresponding proton densities to predict the SEY required to avoid instabilities. That prediction and the information provided by the SEY measurements provide helpful information regarding the risks of electron cloud effects at future beam intensities at Fermilab.

Monday, February 3, 2019 at 4:00 pm

Speaker: Ziad Melhem, Oxford Instruments NanoScience

Title:Industrial Perspective on Superconducting Technologies and Applications

Abstract:

Advancements in superconductor materials are enabling a new class of commercial magnets for a variety of applications including nanoscience, quantum technologies and physical sciences. The new superconducting (SC) magnets together with cryogen free technologies are enabling a new class of laboratory and industrial magnets using Low Temperature Superconductors (LTS) with a variety of configurations with different field strengths and operating conditions. New developments of High Temperature Superconductors (HTS) with very high critical current densities and long lengths are extending the capabilities of SC magnets into high fields magnets beyond 23 T, the limit of LTS conductors. The new SC technologies are facilitating the development of large bore, high field "outsert" solenoid magnets that use LTS conductors to provide background fields in a cold bore of between 100 and 320 mm diameter with an associated central magnetic field of 20 and 12 Tesla respectively operating at 4.2 Kelvin without the need for complex cryogenics. This new "outsert" technology is enabling major steps forwards in new applications using ultra-high field technology with a variety of magnets under development in laboratories around the world operating at T=4.2K with central flux densities in excess of 25 Tesla. This talk will present an overview of Oxford Instruments technology and product development for a variety of superconducting applications and the challenges and opportunities of developing future superconducting magnets.


Thursday, February 6, 2019 at 4:00 pm

Speaker: Mario Milazzo, MIT

Title:BioRobotics and Materiomics: tools and approaches for scientific and technologic advancements

Abstract:

Part 1: BioRobotics is a multidisciplinary field in which scientists with different backgrounds aim to solve unanswered questions related to Nature and living organisms, as well as to create new devices for improving healthcare. After a preliminary introduction of the field and possible applications, a selection of "human in loop" case studies will be presented by discussing the approach and the main tools employed to meet the desired goals. Part 2: Materiomics is a new emerging field that aims at studying properties of materials at all scales. Investigating hierarchical structures leads to a wide range of opportunities for scientific and technological advancements in terms of materials development as well as of unveiling basic physico-chemical mechanisms with tremendous implications at the macro-scale. Collagen-based materials will be used as case study to present selected advancements in this field.


Tuesday, February 18, 2020 at 4:00 pm

Speaker: Dali Georgobiani, FRIB

Title:How I Turned My Life Around and Switched from Helioseismology to Accelerator Radiation Transport

Abstract:

The Sun is the closest star. Contemporary high-resolution telescopes let us observe its surface in great detail. To gain a better understanding of stellar evolution, astrophysicists look for means to see beneath the solar surface. A new discipline called helioseismology comes to the rescue. Solar convection zone is a resonant cavity. The signatures of oscillations on the surface allow scientists to deduce what is happening inside the Sun. Numerical simulations of solar convection are a versatile tool for deciphering the interplay between solar magnetic fields and convective flows, to interpret the surface signatures of solar oscillations. Solar and stellar simulations deal with large spatial scales: a common unit is Megameters (Mm). The solar convection zone is 200 Mm deep. Comparison of the observed and numerical solar convection, as well as validation of common helioseismic techniques by means of numerical simulations are presented and discussed. After spending 15+ years in solar physics, I had the opportunity to switch my field of interest to accelerator radiation transport, working with much smaller scales such as millibarn. I worked the last 10 years at FRIB as a radiation transport physicist, using previous expertise and knowledge of large multi-scale numerical code development, usage and data processing. The scope included: developing numerical models of the facility and its parts; running MCNP and PHITS Monte Carlo calculations to determine shielding requirements and optimize shielding design, evaluating radiation heating and activation of components to guide design, providing input on material choices, hands-on capabilities, remote handling, activated component storage and removal. As an example, I present the study of tritium production and release within the framework of the FRIB project.

Monday, March 02, 2020 at 4:00 pm

Speaker: Yagmur Torun, IIT

Title:One Step Closer to a Muon Collider: Demonstration of Ionization Cooling by MICE

Abstract:

High brightness muon beams hold great promise for future high energy physics facilities. Use of this heavy lepton in a Muon Collider would allow efficient acceleration and storage in recirculating structures and excellent energy resolution with the full center-of-mass energy available for physics reach. However, with a lifetime of 2.2 microseconds at rest, muons are difficult to produce with large phase space density and all beam manipulations must be made quickly which rules out most beam cooling techniques. One of the main technical challenges for a Muon Collider is cooling the muon beam down to a size that would fit through an affordable accelerator acceptance and produce large luminosity for physics. Ionization cooling is a technique to lower the emittance of a muon beam using energy absorbers to shrink the momentum vector and acceleration along the beam axis to restore the longitudinal component. The Muon Ionization Cooling Experiment (MICE) has demonstrated muon cooling in a short section of cooling channel using liquid hydrogen and lithium hydride energy absorbers, showing the increase in phase space density at the beam core with excellent agreement between simulated and observed performance. This brings us closer to a new class of future machines based on muon beams.

Friday, March 06, 2020 at 11:00 am

Speaker: Fiona Harden, CERN

Title:How a STEM education took me on a journey to CERN’s HiRadMat facility

Abstract:

From a very young age the world of science has always fascinated me. From stories of Archimedes jumping out of the bath shouting “Eureka” – the moment Archimedes principle was born; the apple falling on Newton’s head – bang, gravity; to Ada Lovelace the pioneer of computer programming, STEM education can open the door to different research fields enhancing the knowledge and understanding of our society. As a graduate from an interdisciplinary PhD programme in physics which aimed to accelerate and maximise the impact of new discoveries in bone replacement applications, I have applied the skills afforded by my academic career to innovative research in the UKs largest defence manufacturer and then to CERN. During this seminar I will briefly describe how I went from research into bone materials to working at CERN’s High Radiation to Materials (HiRadMat) user facility. Finally, I will explain HiRadMat in depth, describing how this unique facility providing high energy, high intensity proton beam to R&D experiments across the world enables unique investigation of thermal shock effects on components and prototypes as well as materials examination, beam diagnostic equipment development and Targetry systems assessment.

Tuesday, March 10, 2020 at 4:00 pm

Speaker: Kazami Yamamoto and Pranab Saha, J-PARC

Title:J-PARC 3GeV Rapid Cycling Synchrotron

Abstract:

The 3 GeV rapid cycling synchrotron (RCS) at the Japan Proton Accelerator Research Complex (J-PARC) was constructed to supply high- power proton beams to the Main Ring (MR) synchrotron and Material and Life Science Experimental Facility (MLF). Beam commissioning of the RCS has been continuing since 2007, and last year we successfully achieved the design value of 1-MW, 10 hour operation for MLF. In this seminar, we will introduce the basic design of the RCS, recent improvements and the beam commissioning results.

Tuesday, April 21, 2020 at 4:00 pm

Speaker: Valeri Lebedev, FNAL

Title:Effect of transverse damper noise on beam stability in hadron colliders

Abstract:

The talk discusses an effect of transverse damper noise on beam stability in hadron colliders. The damper noise yields transverse diffusion which changes the particle distribution and results in a reduction of the instability threshold. This phenomenon was observed in the experiments at the LHC where an increase of damper noise caused an instability.

Tuesday, April 28, 2020 at 4:00 pm

Speaker: Daniel Winklehner, MIT

Title:Development and applications of high intensity ion beams using cyclotrons

Abstract:

The IsoDAR cyclotron was initially conceived as the high intensity proton driver for neutrino experiments. Either as the injector to an 800 MeV superconducting ring cyclotron for CP violation studies in the neutrino sector or as a standalone driver producing 60 MeV protons for a search for sterile neutrinos. Since then, multiple additional applications have been proposed in medical isotope production, energy research, and materials science. The aim of the IsoDAR cyclotron design is to provide 10 mA of protons at 60 MeV in cw mode. This is an order of magnitude higher current than commercially available machines can produce. Three novelties allow this jump forward: Pre-bunching and injecting through an RFQ inserted axially into the cyclotron; accelerating H2+ ions rather than protons; designing for optimal utilization of the so-called vortex effect. Here, I will present in detail the technical design of ion source, RFQ and cyclotron, as well as the latest beam dynamics results. I will also describe possible applications outside of neutrino physics.

Tuesday, May 12, 2020 at 1:00 pm

Speaker: Alexey Burov, FNAL

Title:Space Charge Effects for Transverse Collective Instabilities in Circular Machines

Abstract:

This talk will suggest a historical review of growing understanding of transverse coherent instabilities of charged particles beams in circular machines when both Coulomb and wake fields are important.

Tuesday, May 26, 2020 at 4:00 pm

Speaker: Peter Ostroumov, FRIB

Title:FRIB linac commissioning

Abstract:

Recently we demonstrated threshold Key Performance Parameter of the FRIB linac system by acceleration of Ar-36 ion beam up to 204.4 MeV/u. The staged commissioning of the linac started in 2017 with beam acceleration in the CW RFQ and continued in following years by acceleration of argon beam to 2 MeV/u in 2018, to 20 MeV/u in 2019 and KPP energy of 200 MeV/u was achieved on March 19, 2020 by using only 251 SC cavities out of 324. The beam commissioning periods were very short to allow completion of hardware installation in the tunnel. This talk will present status of accelerator systems prior to and during the commissioning, beam tuning procedures, beam measurements and main results of each commissioning stage.

Tuesday, June 2, 2020 at 4:00 pm (POSTPONED)

Speaker: Ram Dhuley, FNAL

Title:Cryocooler conduction cooled SRF cavities for compact particle accelerators

Abstract:

SRF based particle accelerators can be an energy-efficient source of electron irradiation for several high-throughput industrial and environmental applications. The current reliance of the SRF technology on complex liquid helium cryogenic systems, however, can be a barrier to its adoption in industrial settings. In this talk, I will introduce cryocooler conduction cooling – a technique that breaks free from liquid helium, leading to a dramatically simple SRF cryo-system. I will present Fermilab’s efforts for the development of conduction cooled SRF cavities and first experimental results. I will then briefly describe the ongoing designs at Fermilab for compact, conduction cooled SRF based electron accelerators.

Tuesday, June 9, 2020 at 4:00 pm

Speaker: Mike Syphers, NIU

Title:Interpreting Loss Rates in the Muon g-2 Storage Ring

Abstract:

The Muon g-2 Experiment seeks to measure the anomalous magnetic moment of the muon to high precision for direct comparison with the predictions of the Standard Model at an unprecedented level. Using a precision magnetic field with electrostatic quadrupole focusing, the decaying muons produce positrons which can be tracked and analyzed. During the measurements within each data-taking window, muons can be lost from the storage ring prior to their decay due to a variety of other dynamical processes. If the “lost muon” distribution has a different average polarization than the distribution that gets measured by the experimental detectors, then this can lead to a systematic error in the final spin precession frequency analysis and hence an error on the anomalous moment determination. In this talk we investigate possible sources of particle loss and show that the long-term loss rates can be understood in relatively simple terms.

Tuesday, June 9, 2020 at 4:30 pm

Speaker: Diktys Stratakis, FNAL

Title:Application of passive wedge absorbers for improving the performance of the Muon g-2 Experiment

Abstract:

An idea is being presented for momentum selection and momentum-spread reduction for muonbased experiments. The method relies on passing a momentum dispersed beam through a wedgeshaped absorber so that faster particles will get decelerated more than the slower ones. We have designed a proof-of-principle experiment to demonstrate the aforementioned idea along the Fermilab Muon Campus, the facility that produces and delivers beam to the Muon g-2 Experiment. We show that with a properly designed wedge we can tailor the momentum distribution of the passing beam so that to increase the number of muons within the momentum acceptance of the Muon g-2 Experiment. The technique has direct relevance to the Fermilab Muon g-2 Experiment as it can enhance the muon beam intensity and therefore minimize the statistical uncertainty of the anomalous magnetic moment measurement. We experimentally demonstrate that such technique is highly tunable by just adjusting the absorber length and can be used to compress the beam longitudinal phase-space. The data reveal an enhancement in the final muon-flux for the Muon g-2 Experiment, thus paving the way for even more powerful muon-based accelerator facilities. We have designed a proof-of-principle experiment to demonstrate an approach that allows us to precisely shape the beam energy profile with passive wedge absorbers. We implement this idea along the Fermilab Muon Campus, the facility that produces and delivers beam to the Muon g-2 Experiment. We show that with a properly designed wedge we can tailor the momentum distribution of the passing beam so that to increase the number of muons within the momentum acceptance of the Muon g-2 Experiment.

Thursday, June 11, 2020 at 4:00 pm

Speaker: Evan Angelico, University of Chicago

Title:Development of Large-Area MCP-PMT Photodetectors for Particle Time-of-Flight and Undulator Radiation Measurements at Fermilab

Abstract:

A system of Large Area Picosecond Photodetectors (LAPPD) has been constructed at the Fermilab Test Beam Facility (FTBF) to measure charged particles in a time-of-flight (TOF) configuration. A permanent LAPPD based time-of-flight system would represent a world-class upgrade of the FTBF to aid the development of detectors in particle physics, nuclear physics, medical imaging, and national security. Experiences from operating an LAPPD-based TOF system have been applied to develop a strategy for measuring angular correlations of undulator radiation from a single circulating electron at the Integrable Optics Test Accelerator (IOTA) at Fermilab. Quantum-optical characteristics of the two photons emitted in one pass of a single electron may play a role in the operation of x-ray free electron lasers and optical-stochastic beam-cooling systems.

Tuesday, June 16, 2020 at 4:00 pm

Speaker: John Mammosser, ORNL

Title:The Proton Power Upgrade project status at the Spallation Neutron Source

Abstract:

The Spallation Neutron Source (SNS) facility is a user facility designed for studies of the structure and dynamics of materials using thermal and cold neutrons.SNS employs a linear accelerator (linac) to produce a 1-ms-long negative-hydrogen ion (H?) beam 60 times per second and accelerate it to 1GeV, resulting in a total beam power of 1.4 MW. The Proton Power Upgrade (PPU) project is currently underway at SNS. The PPU project aims to double the beam power capability to 2.8 MW for which beam energy will be increased to 1.3 GeV by adding an additional seven new superconducting cryomodules and average beam current will be increased by 50%. PPU also provides a 2.0-MW capable target for the current target station and the remaining power is planned to be delivered to a new second target station.

Thursday, June 18, 2020 at 4:00 pm

Speaker: Pierre Korysko, University of Oxford

Title:Intensity-dependent effects in the Accelerator Test Facility 2 and extrapolation to future electron-positron linear colliders

Abstract:

The high energy physics community considers electron-positron linear colliders in order to complement the results obtained at the Large Hadron Collider. In order to achieve the design luminosity above 10$^{34}$ cm$^{-2}$s$^{-1}$, these linear colliders require a nanometer beam size at the Interaction Point (IP). The electron and positron beams are transported inside the Beam Delivery Systems (BDS) from the linear accelerators (LINACS) to the IP. The beam is focused by two strong quadrupoles in the Final Focus System (FFS) where chromatic effects and aberrations are corrected thanks to a local chromaticity correction scheme. Two projects are being studied now, the International Linear Collider (ILC) and the Compact Linear Collider (CLIC). Their FFS and the local chromaticity correction are being tested at the Accelerator Test Facility 2 (ATF2) at KEK in Japan. This test facility has been studying this matter for more than 20 years, achieving two of its main goals: obtaining a stable beam size around 37 nm at the IP and an orbit stabilisation with a nanometer precision at the IP. However, these goals were achieved at 10\% of the nominal beam intensity. Indeed, when increasing the beam intensity, the beam becomes more unstable and its size grows. This is mainly due to wakefields in the ATF2 extraction line. Ultra-relativistic electrons going through the beam pipe interact with the surrounding structure and create an electromagnetic field, the wakefield. This field interacts with electrons inside the same bunch (short-range wakefield) but also with electrons in the following bunches (long-range wakefield). In ATF2, one considers that bellows, flanges and cavity BPMs are the main sources of wakefield. This effect results in increasing significantly the beam size beam at the IP. This presentation will show the impact of these intensity-dependent effects inside ATF2 and how to mitigate them. It will also show the impact of the same intensity-dependent effects in future electron-position linear colliders, the ILC and CLIC.

Tuesday, June 23, 2020 at 4:00 pm

Speaker: Alex Lumpkin, FNAL

Title:Submicropulse Electron-Beam Dynamics Correlated with Short-Range Wakefields in TESLA-type Superconducting rf Cavities

Abstract:

We report direct observations of sub-micropulse beam centroid shifts (head-tail kicks) correlated with short-range wake fields generated by off-axis electron beam steering in TESLA-type superconducting rf cavities. The experiments were performed at the Fermilab Accelerator Science and Technology (FAST) Facility using its unique configuration of a photocathode rf gun injecting beam into two separated nine-cell cavities. The cavities are in series with corrector magnets and beam position monitors (BPMs) located before, between, and after them. The off-axis steering in the cavity was guided by the rf BPM data and higher order mode (HOM) circuitry targeting the first and second dipole passbands. The centroid shifts of up to 300 µm from head to tail of the ~10-ps-long micropulses at 500 pC/b in a 3-MHz pulse train were measured via optical transition radiation at a downstream screen with a Hamamatsu C5680 synchroscan streak camera. We also showed we could compensate such kicks from the first cavity with the short range wakefields (SRW) in the second cavity, and we observed the dilution of the beam size in the tail of the pulses. A simple numerical model of the SRW effect in a single TESLA cavity is compared to the experiment successfully. In principle, these fundamental results may be scaled to cryomodule configurations of major free-electron laser (FEL) facilities such as the European XFEL, Linac Coherent Light Source or LCLS-II XFEL, and the conceptual international linear collider.

Tuesday, June 30, 2020 at 4:00 pm

Speaker: Athula Wickremasinghe, FNAL

Title:Muon Monitor Data with Machine Learning Applications to Maintain the Quality of the NuMI Neutrino Beam

Abstract:

The NuMI target facility produces an intense muon neutrino beam for long baseline neutrino experiments. A muon monitor which measures muon beam profile, is a key beam element to maintain the quality of muon neutrino beam. Three arrays of muon monitors located in the downstream of the hadron absorber provide the measurements of the primary beam quality. We studied the response of muon monitors with the proton beam profile changes and focusing horn current variations. The responses of muon monitors have been used to implement Machine Learning (ML) algorithms to monitor the beam quality. Applications of ML techniques have shown the capabilities of identifying incidents, predicting the beam parameters and horn current with a significant accuracy.

Tuesday, July 7, 2020 at 4:00 pm

Speaker: Ram Dhuley, FNAL

Title:Cryocooler conduction cooled SRF cavities for compact particle accelerators

Abstract:

SRF based particle accelerators can be an energy-efficient source of electron irradiation for several high-throughput industrial and environmental applications. The current reliance of the SRF technology on complex liquid helium cryogenic systems, however, can be a barrier to its adoption in industrial settings. In this talk, I will introduce cryocooler conduction cooling – a technique that breaks free from liquid helium, leading to a dramatically simple SRF cryo-system. I will present Fermilab’s efforts for the development of conduction cooled SRF cavities and first experimental results. I will then briefly describe the ongoing designs at Fermilab for compact, conduction cooled SRF based electron accelerators.

Tuesday, July 14, 2020 at 4:00 pm

Speaker: Ihar Lobach, University of Chicago

Title:Study of photon statistics of undulator radiation in the IOTA storage ring. Including the case of a single electron in the ring

Abstract:

There have been two recent experiments studying statistical properties of undulator radiation in the Integrable Optics Test Accelerator (IOTA) storage ring at Fermilab. The first experiment studies the turn-to-turn fluctuations in the number of photons emitted by a bunch consisting of many electrons (beam current of several mA). This experiment shows that the fluctuations depend on the shape and size of the electron bunch. It reveals the possibility to measure the small vertical size of the flat beam in IOTA, when conventional synchrotron radiation monitors may be unreliable due to the diffraction limit. The second experiment studies the photon statistics of undulator radiation generated by a single electron circulating in the ring, when, on average, there is only one photocount per 300 revolutions. The collected data are analyzed to find possible deviations from the expected Poisson process exhibiting uncorrelated detection events.