arXiv subjects

A. Romanov

Publications and source records attributed to A. Romanov.

At least 19 recordsLinked to original sources

arXiv2025

Proton Dynamics Scenarios in the Integrable Optics Test Accelerator (IOTA) at Fermilab

The Integrable Optics Test Accelerator (IOTA) at Fermilab provides a versatile platform for studying the interplay of space-charge, impedance, and non-linear optics in high-intensity hadron beams within synchrotrons and storage rings. This report examines the parameters and dynamics of 2.5 MeV proton beam operations in two configurations of the bare IOTA lattice (dipoles, quadrupoles, sextupoles, and rf cavity only): one for demonstrating Non-linear Integrable Optics with the Danilov-Nagaitsev magnet, and the other for use with electron cooling. We offer order-of-magnitude estimates of the transverse emittance growth rate as a function of beam intensity, highlighting contributions from residual gas scattering, intra-beam scattering, and space-charge effects. Under nominal conditions, the beam lifetime is projected to be less than 7 minutes at low intensity with the current vacuum quality, and fewer than 100,000 turns at high intensity due to strong space-charge effects. The calculations presented here will guide strategies to mitigate emittance growth and inform future IOTA experiments.

physics.acc-ph↗

arXiv2025

CayleyPy RL: Pathfinding and Reinforcement Learning on Cayley Graphs

This paper is the second in a series of studies on developing efficient artificial intelligence-based approaches to pathfinding on extremely large graphs (e.g. $10^{70}$ nodes) with a focus on Cayley graphs and mathematical applications. The open-source CayleyPy project is a central component of our research. The present paper proposes a novel combination of a reinforcement learning approach with a more direct diffusion distance approach from the first paper. Our analysis includes benchmarking various choices for the key building blocks of the approach: architectures of the neural network, generators for the random walks and beam search pathfinding. We compared these methods against the classical computer algebra system GAP, demonstrating that they "overcome the GAP" for the considered examples. As a particular mathematical application we examine the Cayley graph of the symmetric group with cyclic shift and transposition generators. We provide strong support for the OEIS-A186783 conjecture that the diameter is equal to n(n-1)/2 by machine learning and mathematical methods. We identify the conjectured longest element and generate its decomposition of the desired length. We prove a diameter lower bound of n(n-1)/2-n/2 and an upper bound of n(n-1)/2+ 3n by presenting the algorithm with given complexity. We also present several conjectures motivated by numerical experiments, including observations on the central limit phenomenon (with growth approximated by a Gumbel distribution), the uniform distribution for the spectrum of the graph, and a numerical study of sorting networks. To stimulate crowdsourcing activity, we create challenges on the Kaggle platform and invite contributions to improve and benchmark approaches on Cayley graph pathfinding and other tasks.

cs.LG↗

arXiv2024

Ionization Profile Monitors for the IOTA Proton Beam

Ionization profile monitors (IPMs) are widely used in accelerators for non-destructive and fast diagnostics of high energy particle beams. Two such monitors - one vertical and one horizontal - are being developed for installation in the IOTA storage ring at Fermilab. They will be used for turn-by-turn (microseconds scale) measurements of the 70 MeV/c IOTA proton beam sizes. In this paper we present the IPMs design (largely following the FNAL Booster IPMs which employ no external guiding magnetic fields), their mechanical, vacuum, and electric subsystems and DAQ, and discuss anticipated effects on the beams circulating in IOTA.

physics.acc-ph↗

arXiv2024

Proton beam dynamics in bare IOTA with intense space-charge

We are commissioning a 2.5-MeV proton beam for the Integrable Optics Test Accelerator at Fermilab, allowing experiments in the strong space-charge regime with incoherent betatron tune shifts nearing 0.5. Accurate modelling of space-charge dynamics is vital for understanding planned experiments. We compare anticipated emittance growth and beam loss in the bare IOTA configuration using transverse space-charge models in Xsuite, PyORBIT, and MADX simulation codes. Our findings reveal agreement within a factor of 2 in core phase-space density predictions up to 100 synchrotron periods at moderate beam currents, while tail distributions and beam loss show significant differences.

physics.acc-ph↗

arXiv2023

Status of the IOTA Proton Injector

The IOTA Proton Injector (IPI), currently under installation at the Fermilab Accelerator Science and Technology facility (FAST), is a machine capable of delivering 20 mA pulses of protons at 2.5 MeV to the Integrable Optics Test Accelerator (IOTA) ring. First beam in the IPI beamline is anticipated in the first half of 2024, when it will operate alongside the existing electron injector beamline to facilitate further beam physics research and continued development of novel accelerator technologies at the IOTA ring. This report details the expected operational profile, known challenges, and the current state of installation.

physics.acc-ph↗

arXiv2023

Experimental Single Electron 4D Tracking in IOTA

This paper presents the results of the first experiments on 4D tracking of a single electron using a linear multi-anode photomultiplier tube. The reported technology makes it is possible to fully track a single electron in a storage ring, which requires tracking of amplitudes and phases for both, slow synchrotron and fast betatron oscillations. Complete tracking of a point-like object enabled the first direct measurements of single-particle dynamical properties, including dynamical invariants, amplitude-dependent oscillation frequencies, and chaotic behavior.

physics.acc-ph↗

arXiv2023

Classification of networks-on-chip in the context of analysis of promising self-organizing routing algorithms

This paper contains a detailed analysis of the current state of the network-on-chip (NoC) research field, based on which the authors propose the new NoC classification that is more complete in comparison with previous ones. The state of the domain associated with wireless NoC is investigated, as the transition to these NoCs reduces latency. There is an assumption that routing algorithms from classical network theory may demonstrate high performance. So, in this article, the possibility of the usage of self-organizing algorithms in a wireless NoC is also provided. This approach has a lot of advantages described in the paper. The results of the research can be useful for developers and NoC manufacturers as specific recommendations, algorithms, programs, and models for the organization of the production and technological process.

cs.NI↗

arXiv2023

IOTA Proton Injector Beamline Installation

The IOTA Proton Injector (IPI), currently under installation at the Fermilab Accelerator Science and Technology facility, is a beamline capable of delivering 20-mA pulses of protons at 2.5 MeV to the Integrable Optics Test Accelerator (IOTA) ring. First beam in the IPI beamline is anticipated in 2023, when it will operate alongside the existing electron injector beamline to facilitate further fundamental physics research and continued development of novel accelerator technologies in the IOTA ring. This report details the expected operational profile, known challenges, and the current state of installation.

physics.acc-ph↗

arXiv2022

Experimental demonstration of OSC at IOTA: IOTA Run #3 Report

Optical Stochastic Cooling (OSC) is an optical-bandwidth extension of Stochastic Cooling that could advance the state-of-the-art cooling rate in beam cooling by three to four orders of magnitude [1-3]. The concept of OSC was first suggested in the early 1990s by Zolotorev, Zholents and Mikhailichenko, and replaced the microwave hardware of SC with optical analogs, such as wigglers and optical amplifiers. A number of variations on the original OSC concept have been proposed, and while a variety of proof-of-principle demonstrations and operational uses have been considered, the concept was not experimentally demonstrated up to now [4-9]. An OSC R&D program has been underway at IOTA for the past several years [4]. Run #3 of the IOTA ring, which began in Nov. 2020 and concluded in Aug. 2021, was focused on the worlds first experimental demonstration of OSC. The experimental program was successful in demonstrating and characterizing the OSC physics with the major outcomes including strong cooling in one, two and three dimensions, validation of the theoretical models of OSC and the demonstration of OSC with a single electron. This report briefly describes the activities and major milestones of the OSC program during Run #3. Detailed descriptions of the OSC theory, conceptual design and hardware elements can be found in reference [4].

physics.acc-ph↗

arXiv2022

First Experimental Demonstration of Optical Stochastic Cooling

Particle accelerators and storage rings have been transformative instruments of discovery, and, for many applications, innovations in particle-beam cooling have been a principal driver of that success1. Beam cooling reduces the spread in particle positions and momenta, while keeping the number of particles constant, and combats diffusive effects, thereby enabling particle accumulation and the production and preservation of intense beams. In the case of particle colliders, cooling increases the likelihood of observing rare physics events. One of the most important conceptual and technological advances in this area was stochastic cooling (SC), which was instrumental in the discovery of the W and Z bosons at CERN and the top quark at Fermilab2-6. SC reduces the random motion of the beam particles through granular sampling and correction of the beams phase-space structure, thus bearing resemblance to a Maxwells demon. The extension of SC from the microwave regime up to optical frequencies and bandwidths has long been pursued as it could increase the achievable cooling rates by three to four orders of magnitude and provide a powerful new tool for future accelerators. First proposed nearly thirty years ago, Optical Stochastic Cooling (OSC) replaces the conventional microwave elements of SC with optical-frequency analogs and is, in principle, compatible with any species of charged-particle beam7,8. Here we describe the first experimental demonstration of OSC in a proof-of-principle experiment9 at the Fermi National Accelerator Laboratorys Integrable Optics Test Accelerator10.

physics.acc-ph↗

arXiv2021

Observation of the cosmic ray shadow of the Sun with the ANTARES neutrino telescope

ANTARES is the largest undersea neutrino telescope and it has been taking data in its final configuration for more than ten years. On their journey to the Earth, cosmic rays can be absorbed by celestial objects, like the Sun, leading to a deficit in the atmospheric muon flux measured by the ANTARES detector, the so-called Sun "shadow" effect. This phenomenon can be used to evaluate fundamental telescope characteristics: the detector angular resolution and pointing accuracy. This work describes the study of the Sun "shadow" effect using the ANTARES data collected between 2008 and 2017. The statistical significance of the Sun shadow observation is $3.7σ$ and the estimated angular resolution value of the ANTARES telescope for downward-going muons is $0.59^{\circ} \pm 0.10^{\circ}$, which is consistent with the expectations obtained from the Monte Carlo simulations and also with the estimation from the Moon "shadow" analysis of 2007-2016 years. No evidence of systematic pointing shift is found and the resulting pointing accuracy is consistent with the expectations.

astro-ph.HE↗

arXiv2021

Conceptual Design Report: Optical Stochastic Cooling at IOTA

The paper presents a journal version of the Design Report on the Optical Stochastic Cooling experiment to be carried out at IOTA ring in Fermilab later this year. It discusses the theory which experiment is based on, beam parameters, major requirements to the storage ring systems and technical details of the experiment implementation.

physics.acc-ph↗

arXiv2018

Commissioning and Operation of FAST Electron Linac at Fermilab

We report results of the beam commissioning and first operation of the 1.3 GHz superconducting RF electron linear accelerator at Fermilab Accelerator Science and Technology (FAST) facility. Construction of the linac was completed and the machine was commissioned with beam in 2017. The maximum total beam energy of about 300 MeV was achieved with the record energy gain of 250 MeV in the ILC-type SRF cryomodule. The photoinjector was tuned to produce trains of 200 pC bunches with a frequency of 3 MHz at a repetition rate of 1 Hz. This report describes the aspects of machine commissioning such as tuning of the SRF cryomodule and beam optics optimization. We also present highlights of an experimental program carried out parasitically during the two-month run, including studies of wake-fields, and advanced beam phase space manipulation.

physics.acc-ph↗

arXiv2018

Beam Phase Space Tomography at FAST Electron Linac at Fermilab

FAST linear accelerator has been commissioned in 2017. Experimental program of the facility requires high quality beams with well-defined properties. Solenoidal fields at photoinjector, laser spot shape, space charge forces and other effects can distort beam distribution and introduce coupling. This work presents results of a beam phase space tomography for a coupled 4D case. Beam was rotated in two planes with seven quads by 180 degrees and images from YaG screen were used to perform SVD based reconstruction of the beam distribution.

physics.acc-ph↗

arXiv2018

Testing of Advanced Technique For Linear Lattice and Closed Orbit Correction By Modeling Its Application For IOTA Ring At Fermilab

Many modern and most future accelerators rely on precise configuration of lattice and trajectory. The Integrable Optics Test Accelerator (IOTA) at Fermilab that is coming to final stages of construction will be used to test advanced approaches of control over particles dynamics. Various experiments planned at IOTA require high flexibility of lattice configuration as well as high precision of lattice and closed orbit control. Dense element placement does not allow to have ideal configuration of diagnostics and correctors for all planned experiments. To overcome this limitations advanced method of lattice analysis is proposed that can also be beneficial for other machines. Developed algorithm is based on LOCO approach, extended with various sets of other experimental data, such as dispersion, BPM-to-BPM phase advances, beam shape information from synchrotron light monitors, responses of closed orbit bumps to variations of focusing elements and other. Extensive modeling of corrections for a big number of random seed errors is used to illustrate benefits from developed approach.

physics.acc-ph↗

arXiv2018

Adaptive Matching Of The IOTA Ring Linear Optics For Space Charge Compensation

Many present and future accelerators must operate with high intensity beams when distortions induced by space charge forces are among major limiting factors. Betatron tune depression of above approximately 0.1 per cell leads to significant distortions of linear optics. Many aspects of machine operation depend on proper relations between lattice functions and phase advances, and can be improved with proper treatment of space charge effects. We implement an adaptive algorithm for linear lattice re matching with full account of space charge in the linear approximation for the case of Fermilab's IOTA ring. The method is based on a search for initial second moments that give closed solution and, at the same time, satisfy predefined set of goals for emittances, beta functions, dispersions and phase advances at and between points of interest. Iterative singular value decomposition based technique is used to search for optimum by varying wide array of model parameters.

physics.acc-ph↗

arXiv2017

Linear Lattice and Trajectory Reconstruction and Correction at FAST Linear Accelerator

The low energy part of the FAST linear accelerator based on 1.3 GHz superconducting RF cavities was successfully commissioned. During commissioning, beam based model dependent methods were used to correct linear lattice and trajectory. Lattice correction algorithm is based on analysis of beam shape from profile monitors and trajectory responses to dipole correctors. Trajectory responses to field gradient variations in quadrupoles and phase variations in superconducting RF cavities were used to correct bunch offsets in quadrupoles and accelerating cavities relative to their magnetic axes. Details of used methods and experimental results are presented.

physics.acc-ph↗

arXiv2017

Analysis and Measurement of the Transfer Matrix of a 9-cell 1.3-GHz Superconducting Cavity

Superconducting linacs are capable of producing intense, stable, high-quality electron beams that have found widespread applications in science and industry. The 9-cell 1.3-GHz superconducting standing-wave accelerating RF cavity originally developed for $e^+/e^-$ linear-collider applications [B. Aunes, {\em et al.} Phys. Rev. ST Accel. Beams {\bf 3}, 092001 (2000)] has been broadly employed in various superconducting-linac designs. In this paper we discuss the transfer matrix of such a cavity and present its measurement performed at the Fermilab Accelerator Science and Technology (FAST) facility. The experimental results are found to be in agreement with analytical calculations and numerical simulations.

physics.acc-ph↗