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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Technological developments and accelerator improvements for the FRIB beam power ramp-up

The Facility for Rare Isotope Beams (FRIB) began operation with 1 kW beam power for scientific users in May 2022 upon completion of 8 years of project construction. The ramp-up to the ultimate beam power of 400 kW, planned over a 6-year period, will enable the facility to reach its full potential for scientific discovery in isotope science and applications. In December 2023, a record-high beam power of 10.4 kW uranium was delivered to the target. Technological developments and accelerator improvements are being made over the entire facility and are key to completion of the power ramp-up. Major technological developments entail the phased deployment of high-power beam-intercepting systems, including the charge strippers, the charge selection systems, the production target, and the beam dump, along with support systems, including non-conventional utilities (NCU) and remote handling facilities. Major accelerator improvements include renovations to aging legacy systems associated with experimental beam lines and system automation for improved operational efficiency and better machine availability. Experience must be gained to safely handle the increased radiological impacts associated with high beam power; extensive machine studies and advanced beam tuning procedures are needed to minimize uncontrolled beam losses for the desired operating conditions. This paper discusses the technological developments and accelerator improvements with emphasis on major R&D efforts.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Acceleration of uranium beam to record power of 10.4 kW and observation of new isotopes at Facility for Rare Isotope Beams

The Facility for Rare Isotope Beams (FRIB) is a major nuclear physics facility for research with fast, stopped, and reaccelerated beams that was successfully commissioned in May 2022. A key capability of FRIB is the production of an acceleration of the uranium beam, but this capability requires the facility to work at the design limits of the lowest charge-to-mass ratio and the highest power density on the beam intercepting devices. This paper presents techniques for overcoming the significant challenges in accelerating the uranium beam, culminating in the demonstration of 10.4 kW on target, and the discovery of three new isotopes. The high-power uranium beam enabled us to produce and identify G 88 a , A 93 s , and S 96 e , within the first 24 h of operation. The successful uranium operation at FRIB sets a new record for accelerated uranium beam power above 10 kW and opens a new avenue of research with rare isotopes. Published by the American Physical Society 2024

43 PARTICLE ACCELERATORS↗
DOE OSTI2025

Measurement techniques using the electron beam profile scanner at the Fermilab Main Injector

This work presents techniques for non-invasive transverse profile measurements of high-intensity proton beams using an Electron Beam Profile Scanner (EBPS). The EBPS utilizes low-energy electrons as a probe to analyze the transverse size of proton beams, allowing for potential analysis on a single-bunch basis. Recent upgrades to the Fermilab Main Injector have enhanced beam power on target to 1 MW, with future developments targeting 2 MW. The higher beam power has increased the demand for non-invasive diagnostics, as invasive methods can disrupt operations.The techniques presented include 1) the slow scan technique, which serves as a proof of concept for the probe beam, 2) the one-shot scan technique for measuring horizontal beam profiles, and 3) the raster scan technique for analyzing horizontal beam profiles as a function of the longitudinal distribution of the beam. The profiles obtained will be crucial for studying and understanding instabilities in high-power, high-intensity proton beams. This will contribute to optimizing the operation of high-power proton accelerators by minimizing beam loss, activation, and damage to both the diagnostics and the accelerator components.

Mwaniki, Matilda [IIT, Chicago]↗
DOE OSTI2020

Design Considerations and Operational Features of the Collimators for the Fermilab Main Injector and Recycler

The Fermilab Main Injector system delivers 700 kW of 120 GeV Proton beam for neutrino experiments. Since 2013 this has been achieved using slip stacking accumulation in the Recycler with up to 12 batches from the Fermilab Booster per Main Injector Ramp Cycle. To control activation from beam loss, collimation systems in the Booster to Recycler transfer line, in the Recycler and in the Main Injector are employed. Residual radiation measurements around the ring with detailed studies at the collimators are required to maintain adequate loss control. We will review design considerations, operational parameters and activation results for more than ten years of operation. Simulations with MARS15 are used to explore the activation rates and the isotopic composition of the resulting activation.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

SRF Cavity Instability Detection with Machine Learning at CEBAF

During the operation of CEBAF, one or more unstable superconducting radio-frequency (SRF) cavities often cause beam loss trips while the unstable cavities themselves do not necessarily trip off. Identifying an unstable cavity out of the hundreds of cavities installed at CEBAF is difficult and time-consuming. The present RF controls for the legacy cavities report at only 1 Hz, which is too slow to detect fast transient instabilities. A fast data acquisition system for the legacy SRF cavities is being developed which samples and reports at 5 kHz to allow for detection of transients. A prototype chassis has been installed and tested in CEBAF. An autoencoder based machine learning model is being developed to identify anomalous SRF cavity behavior. The model is presently being trained on the slow (1 Hz) data that is currently available, and a separate model will be developed and trained using the fast (5 kHz) DAQ data once it becomes available. This paper will discuss the present status of the new fast data acquisition system and results of testing the prototype chassis. This paper will also detail the initial performance metrics of the autoencoder model.

Carpenter, A.↗
DOE OSTI2025

Evaluating a Transition-jump System for the Fermilab Main Injector Using Xsuite

We describe an Xsuite simulation framework for the Fermilab Main Injector (MI) along with an evaluation of transition-crossing behaviors in the accelerator. In particular, we studied the introduction of quadrupole magnets into the lattice as part of a transition-jump system that will be implemented through the $2^{nd}$ Proton Improvement Plan (PIP-II). Simulated beam losses spurred by transition-induced instabilities were assessed under several systematic effects, including MI quad errors, magnet-to-magnet variability in the jump magnets, power-supply errors, and timing jitter.

Schreckenberger, A. P. [Fermilab] (ORCID:000000016↗
DOE OSTI2026

Dynamic aperture studies at the Fermilab recycler ring

As part of the Proton Improvement Plan II (PIP-II), Fermilab aims to increase beam intensity delivered to neutrino experiments. In this context, higher intensity injection into the Recycler Ring enhances space charge effects, pushing operations closer to third-order resonances. These resonances reduce the Dynamic Aperture (DA), leading to increased beam loss. This study presents simulations of DA as a function of tune in the Recycler Ring, incorporating chaos indicators such as the Reversibility Error Method (REM) and Frequency Map Analysis (FMA). The effectiveness of existing resonance mitigation strategies is evaluated by quantifying their ability to delay DA degradation. Additionally, the study examines how space charge detuning and DA limitations dictate viable operational tune points for the Recycler Ring.

Gonzalez-Ortiz, Cristhian [Fermilab]↗
DOE OSTI2021

Modeling Transverse Space Charge effects in IOTA with pyORBIT

The role and mitigation of space charge effects are important aspects of the beam physics research to be performed at the Integrable Optics Test Accelerator (IOTA) at Fermilab. The impact of nonlinear integrability (partial and complete) on space charge driven incoherent and coherent resonances will be a new feature of this accelerator and has the potential to influence the design of future low energy proton synchrotrons. In this report we model transverse space charge effects using the PIC code pyORBIT. First we benchmark the single particle tracking results against MADX with checks on symplecticity, tune footprints, and dynamic aperture in a partially integrable lattice realized with a special octupole string insert. Our space charge calculations begin with an examination of the 4D symplecticity. Short term tracking is done first with the initial bare lattice and then with a matching of the rms values with space charge. Next, we explore slow initialization of charge as a technique to establish steady state and reduce emittance growth and beam loss following injection into a mismatched lattice. We establish values of space charge simulation parameters so as to ensure numerical convergence. Finally, we compare the simulated space charge induced tune shifts and footprints against theory.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Beam Optics Studies for Larger Beampipe Diameters for the LAMP-PSR

The proposed beampipe diameter increase of the PSR beamlines for the LAMP PSR upgrade is expected decrease beam loss due to tuning errors and misalignment. However, a larger beampipe diameter would require increasing the pole-to-pole gap height within all magnets in the PSR (dipole gap, quadrupole bore, etc.). This would in turn affect the extent and profile of the fringe fields at the ends of the magnets, altering the effective length of the magnets and thus the magnetic optics. In this work, we used the simulation code MAD-X to model the PSR lattice for different beampipe diameters. The results of these simulations will be later used to benchmark particle simulations using the code pyORBIT. The MAD-X simulations are described, and the simulation results are discussed in this technote.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

SRF Cavity Instability Detection with Machine Learning at CEBAF

During the operation of CEBAF, one or more unstable superconducting radio-frequency (SRF) cavities often cause beam loss trips while the unstable cavities themselves do not necessarily trip off. Identifying an unstable cavity out of the hundreds of cavities installed at CEBAF is difficult and time-consuming. The present RF controls for the legacy cavities report at only 1 Hz, which is too slow to detect fast transient instabilities. A fast data acquisition system for the legacy SRF cavities is being developed which samples and reports at 5 kHz to allow for detection of transients. A prototype chassis has been installed and tested in CEBAF. An autoencoder based machine learning model is being developed to identify anomalous SRF cavity behavior. The model is presently being trained on the slow (1 Hz) data that is currently available, and a separate model will be developed and trained using the fast (5 kHz) DAQ data once it becomes available. This paper will discuss the present status of the new fast data acquisition system and results of testing the prototype chassis. This paper will also detail the initial performance metrics of the autoencoder model.

Carpenter, A.↗
DOE OSTI2024

Automated Calibration System for Beam Current Monitor

The Beam Current Monitor (BCM) measures the instantaneous current in a beam. This work aims to develop an automated calibration system for the BCM to address the need for calibration without interrupting beam operation. We strive to create a synchronous calibration method integrated into the master timeline by utilizing the pulsed nature of synchrotrons to run calibration pulses during inter-pulse gaps. This improvement should enhance operational efficiency, ensure safe operation, and help mitigate beam loss, all by enabling intermittent calibration during the operation of the accelerator. This is accomplished by developing a Python program that interfaces with a Keithley 6221 DC and AC source and a Keithley 2182A Nanovoltmeter. The program configures both of these devices to perform a selected mode of the current sweep, allows for the initiation of the current sweep, collects the measured voltage data from the 2182A, stores the collected data to the computer in a CSV file, and graphs the collected data.

Haller, James↗
DOE OSTI2025

Mechanical Design and Vacuum Pressure Impregnation of Combined Function Electromagnets

There are 96 combined function magnets, 48 focusing and 48 defocusing, that have been in operation in the Fermi NAL Booster without a critical failure requiring replacement for over 50 years. The Proton Improvement Plan-II (PIP-II) poses risk to these magnets and Fermilab does not currently have the tooling or knowledge of process to fabricate spares. Two new variants of these magnets are needed to reduce beam loss by having a larger aperture (Booster Gradient Defocusing Wide, or BGDS) and create space for a new injection system (Booster Gradient Defocusing Short, or BGDS). Risk of failure and need for spares will increase substantially with the implementation of PIP-II in consequence of a frequency increase from 15 Hz to 20 Hz and a 30 percent increase in peak to ground voltage. The BGDS and BGDW magnets will be fabricated in the same way as the current booster magnets so that future combined function magnet spares can be produced using learned processes.

Szabo, B. [Fermilab]↗
DOE OSTI2025

Evaluating a Transition-Jump System for the Fermilab Main Injector Using Xsuite

We describe an Xsuite simulation framework for the Fermilab Main Injector (MI) along with an evaluation of transition-crossing behaviors in the accelerator. In particular, we studied the introduction of quadrupole magnets into the lattice as part of a transition-jump system that will be implemented through the $2^{nd}$ Proton Improvement Plan (PIP-II). Simulated beam losses spurred by transition-induced instabilities were assessed under several systematic effects, including MI quad errors, magnet-to-magnet variability in the jump magnets, power-supply errors, and timing jitter.

Schreckenberger, Adam Paul [Fermilab] (ORCID:00000↗
DOE OSTI2025

Dynamic Aperture Studies at the Fermilab Recycler Ring

As part of the Proton Improvement Plan II (PIP-II), Fermilab aims to increase beam intensity delivered to neutrino experiments. In this context, higher intensity injection into the Recycler Ring enhances space charge effects, pushing operations closer to third-order resonances. These resonances reduce the Dynamic Aperture (DA), leading to increased beam loss. This study presents simulations of DA as a function of tune in the Recycler Ring, incorporating chaos indicators such as the Reversibility Error Method (REM). The effectiveness of existing resonance mitigation strategies is evaluated by quantifying their ability to delay DA degradation. Additionally, the study examines how space charge detuning and DA limitations dictate viable operational tune points for the Recycler Ring.

Gonzalez-Ortiz, Cristhian Eduardo [Fermilab]↗
DOE OSTI2026

Estimation of the Required Dipole Corrector Magnetic Field for PIP-II Injection Based on Beam Studies

The Fermilab Booster will accept a 600 µs beam pulse from the new superconducting Linac for PIP-II operations. The Booster is a rapid-cycling synchrotron that uses a resonant magnet circuit ramping at 15 Hz. For PIP-II, the cycle rate will increase to 20 Hz, and the injection pulse length will expand from 40 µs to 600 µs due to the lower output current from the new Linac. Because the Booste main bending field follows a sinusoidal waveform, the magnetic field is not constant during the extended injection window. The longer pulse length and higher repetition rate modify the beam orbit and can lead to increased beam losses. The Booster contains 48 dipole-corrector packages distributed across its 24 periods. Each package includes horizontal and vertical dipoles, quadrupole, sextupole, skew-quadrupole, and skew-sextupole elements. By driving the dipole correctors with an appropriately shaped sinusoidal waveform during injection, we can compensate the changing main field and create an effectively flat bending field—referred to as flat injection. Over the past several years, machine studies have been performed to characterize the required correction fields and to determine the corresponding power-supply specifications needed for PIP-II operation. In this presentation, we will summarize the study results and discuss the estimated magnetic field requirements and power supply parameters for achieving flat injection in the Booster.

Seiya, K. [Fermilab] (ORCID:0000000250576943)↗
DOE OSTI2026

Using Chromaticity to Suppress Instabilities at 𝜸𝒕 Transition

For many synchrotrons which cross $\gamma_t$ transition, a high intensity threshold has been identified beyond which significant beam losses are observed. These losses are due to a high-intensity mode coupling instability, which can be suppressed by adjusting the chromaticity curve to cross zero slightly after $\gamma_t$ transition.

Balcewicz, M. A. [Fermilab] (ORCID:000900055722252↗
NASA NTRS1974

Antennas for spaceborne microwave radiometers

Principles and applications of microwave radiometry to remote sensing of the earth from satellites are reviewed. Examples of some spaceborne radiometer systems currently in use or under consideration are given. The requirements on performance characteristics of microwave antennas for such spaceborne earth sensing radiometers, such as coverage, scanning, spatial resolution, insertion loss, beam efficiency, polarization purity, etc., and their effects on the overall radiometer system performance are discussed.

Shiue, J. C.-C.↗