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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Beam Synchronous for the Rest of Us!

Fermilab’s Tevatron Clock (TCLK) infrastructure has been an integral part of the accelerator control network since the 1980’s. This 10MHz Manchester encoded protocol has enabled flexible, real-time event distribution for thousands of devices connected to the timing network with a high degree of reliability. Forthcoming upgrades to the Fermilab complex (PIP-II, LBNF, ACORN) necessitate higher levels of precision to maintain inter-bunch timing for Instrumentation and Control purposes. This presents as an opportunity to refine the event distribution protocol for tighter synchronization between machines, experiments, and eventually far-site operations. This paper outlines a method by which beam-synchronous events may be distributed through asynchronous serial protocols via integration with local LLRF and global PPS reference signals. This method is ideal for synchrotron machines with aggressive frequency sweeps (such as Fermilab's 38~53MHz Booster) and allows for precision timing to be maintained across machines without specialized hardware.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

PIP-II 800 MeV Proton Linac Beam Pattern Generator

The PIP2 IT Beam Pattern Generator is the system that synchronizes beam injection and the RF systems between the PIP2 LINAC to the Booster. The RF frequencies of these two accelerator systems are not harmonically related. Synchronization is accomplished by controlling two MEBT Beam Choppers, which select 162.5MHz beam bunches from the LEBT and RFQ to produce an appropriate reduced beam bunch pattern that enables bucket-to-bucket transfer to the Booster RF at 46.46MHz (84th harmonic). This chopping pattern also reduces the beam current to an average of 2mA over the Booster injection, matching the Linac nominal beam current. The BPG also generates the RF frequency/phase reference which the Booster will phase lock to during injection. The BPG is fully programmable, allowing for arbitrary beam patterns with adjustable timing parameters, having a fine adjustment resolution of 38ps. The latter is accomplished using digital signal processing techniques. This paper discusses the design of the BPG, its construction, test results, and operational experience after being integrated into the PIP2 IT test accelerator and concludes with a discussion of the system’s performance and future plans.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Multipulse Optical-Rectification-Based THz Source for Accelerator Applications

THz sources offer the potential for higher frequencies and higher breakdown thresholds in accelerating structures in comparison with conventional RF sources. They also benefit from larger field strengths, field gradients, better beam synchronization and compactness. In this work, we first present the development of a 49μJ single-cycle THz source centered at 0.6 THz that provides fields over 30 MV/m. With further modifications, multicycle pulses were produced, narrowing the bandwidth of the source and potentially easing the coupling of THz radiation to relativistic electron beams and increasing the usability in other areas of research.

Lenz, Maximilian (ORCID:0009000579693042)↗
DOE OSTI2024

Proton Improvement Plan II (PIP-II) Clock and Timing

The PIP-II timing system is planned to be a two-part system consisting of a global timing system (referred to as ACLK) that provides high level, event-based timing for the whole Fermilab accelerator complex while the second part is a RF synchronized clock system unique to the PIP-II Linac itself (referred to as LCLK). The ACLK System will make use of an external 10 MHz GPS based signal source as a reference for its 650 MHz phase lock as it is the reference frequency for the TCLK output of the system (needed to support legacy hardware around complex). The LCLK System will use a PIP-II Linac RF reference (162.5 MHz) from the Linac LLRF system to allow beam synchronized event placement. Both the ACLK and LCLK systems will have a clock output with a data frame of 16 event bits + 32 data bits with frames broadcast at 650 MHz, phase locked to the 10MHz reference in the case of ACLK and the PIP-II LLRF sourced 162.5 MHz reference in the case of LCLK.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

First direct observations of gear-changing in a collider

In this work we perform the first demonstration of gear-changing in a real world collider. Gear-changing refers to a collision scheme where each ring of a collider stores a different harmonic number of bunches. These bunches are kept synchronized using different velocities. Such a system has been theorized, but has now been demonstrated using the Double ElectroStatic Ion Ring ExpEriment (DESIREE) in Stockholm Sweden. The experiment was able to demonstrate a gear-changing system, with both four on three bunches and five on four bunches. We determined a measurable parameter that shows a gear-changing system out to $37500$ turns of the slow beam (1 second). We were also able to detect a measurable longitudinal beam-beam interaction. We developed insights into how to control this type of system, opening up new possibilities, and showing that DESIREE can be used for gear-changing research.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Dynamic beam shaping—Improving laser materials processing via feature synchronous energy coupling

Today, tailored laser beams are rarely used and thus an opportunity to optimize existing or introduce new processes is missed. New methods of dynamic beam shaping have the potential to change that in future. This keynote paper deals with methods allowing a transient energy input into the workpiece at such time scales that the underlying interaction processes are guided towards the desired result. It shows principles, categorizes necessary system technology, and gives application examples to familiarize the reader with the topic. It postulates that time-scale-dependent coupling between transient energy input and addressed process features is key for achieving the optimum.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Multi-messenger dynamic imaging of laser-driven shocks in water using a plasma wakefield accelerator

Understanding dense matter hydrodynamics is critical for predicting plasma behavior in environments relevant to laser-driven inertial confinement fusion. Traditional diagnostic sources face limitations in brightness, spatiotemporal resolution, and in their ability to detect relevant electromagnetic fields. In this work, we present a dual-probe, multi-messenger laser wakefield accelerator platform combining ultrafast X-rays and relativistic electron beams at 1 Hz, to interrogate a free-flowing water target in vacuum, heated by an intense 200 ps laser pulse. This scheme enables high-repetition-rate tracking the evolution of the interaction using both particle types. Betatron X-rays reveal a cylindrically symmetric shock compression morphology assisted by low-density vapor, resembling foam-layer-assisted fusion targets. The synchronized electron beam detects time-evolving electromagnetic fields, uncovering charge separation and ion species differentiation during plasma expansion – phenomena not captured by photons or hydrodynamic simulations. We show that combining both probes provides complementary insights spanning kinetic to hydrodynamic regimes, highlighting the need for hybrid physics models to accurately predict fusion-relevant plasma behavior.

imaging techniques↗
DOE OSTI2024

Design considerations for colliders using co-moving beams for fusion cross section research

Collisions between beams moving in the same direction but with different velocities allow for low center of mass energy collisions with higher energy beams. These types of systems lend themselves to fusion interactions since they require low center of mass kinetic energies but can benefit from higher energies in the constituent beams. Here we cover the design considerations for a machine that could study these types of interactions. Furthermore, we especially highlight reactants that can be stored and collided in a single ring, using a collision timing system known as gear-changing, which could allow for a proof-of-concept experiment in an existing machine.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Estimating Ice Water Content for Winter Storms from Millimeter-Wavelength Radar Measurements Using a Synthesis of Polarimetric and Dual-Frequency Radar Observations

The potential of millimeter-wavelength radar-based ice water content (IWC) estimation is demonstrated using a Ka-band Scanning Polarimetric Radar (KASPR) for the U.S. northeast coast winter storms. Two IWC relations for Ka-band polarimetric radar measurements are proposed: one that uses a combination of the radar reflectivity Z and the estimated total number concentration of snow particles N t and the other based on the joint use of Z, specific differential phase K DP , and the degree of riming f rim . A key element of the algorithms is to obtain the “Rayleigh-equivalent” value of Z measured at the Ka band, i.e., the corresponding Z at a longer radar wavelength for which Rayleigh scattering takes place. This is achieved via polarimetric retrieval of the mean volume diameter D m and incorporating the relationship between the dual-wavelength ratio DWR S/Ka and D m . Those techniques allow for retrievals from single millimeter-wavelength radar measurements and do not necessarily require the dual-wavelength ratio (DWR) measurements, if the DWR–D m relation and Rayleigh assumption for Ka-band K DP are valid. Comparison between the quasivertical profile product obtained from KASPR and the columnar vertical profile product generated from the nearby WSR-88D S-band radar measurements demonstrates that the DWR S/Ka can be estimated from the two close radars without the need for collocated radar beams and synchronized antenna scanning and can be used for determining the Rayleigh-equivalent value of Z. As a result, the performance of the suggested techniques is evaluated for seven winter storms using surface disdrometer and snow accumulation measurements.

Cloud retrieval↗
DOE OSTI2026

Performance and Stability Characterization of the ICARUS Light Detection System

The ICARUS detector, a key component of the Short Baseline Neutrino (SBN) Program at Fermilab, consists of two identical T300 modules filled with liquid argon. It is equipped with a Light Detection System (LDS) based on 360 8-inch Hamamatsu R5912-MOD photomultiplier tubes (PMTs) arranged behind the wire planes to collect Vacuum Ultraviolet (VUV, $\sim$ 128 nm) scintillation light. Operating under cryogenic conditions ( $\sim$ 87 K), the LDS is essential for determining the event start time (t0) with nanosecond precision for beam spill synchronization, improving longitudinal spatial resolution, and contributing to the event trigger and cosmic-ray mitigation. The performance of the LDS was investigated addressing both hardware and data analysis aspects. Following a progressive degradation in PMT gain observed during operations at FNAL, systematic gain measurements were first carried out from room temperature down to low temperatures. The results show stable performance at room temperature but a significant, irreversible reduction in gain at low temperatures. Based on these findings, a series of mitigation strategies were implemented in the ICARUS detector to preserve PMT performance and ensure reliable cryogenic operation. Currently, ongoing waveform analysis of the PMT signals is being performed to characterize signal shape, charge integration, and timing properties, aiming to refine and improve the agreement between experimental data and Monte Carlo simulations.

Saia, Clara [U. Catania (main); INAF, Catania; Cat↗
DOE OSTI2025

Laser system design and critical technologies for the NSF OPAL project

The three-year NSF OPAL project is completing the preliminary design of a 2 x 25-PW all-optical parametric chirped-pulse amplification (OPCPA) system capable of delivering 500-J, 20-fs pulses. The design includes two Alpha beamlines that can be co-timed and pointed into two experimental areas for high-intensity research in several configurations. Additionally, a more flexible 2-PW Beta beam can be used in place of one Alpha beam to allow a wider range of focusing geometries and synchronized electron-beam generation for diverse experimental applications. Here, building on the development of the mid-scale MTW-OPAL prototype system, the NSF OPAL project also focuses on advancing essential technologies, such as large-grating fabrication techniques and actively-cooled disk amplifiers.

42 ENGINEERING↗
DOE OSTI2024

Progress in developing a superconducting accelerator for efficient eBeam and X-ray production

The PIP-II Accelerator is an 800 MeV superconducting Linac in the injection chain of the Fermilab accelerator complex. The LLRF systems for the 125 cavities which include a few normal conducting cavities in the warm front-end section, use a variety of LLRF hardware components and sub-systems that are part of the timing and synchronization system. This includes a master oscillator and phase averaging reference line, a beam pattern generator to enable beam transfer between non-harmonic RF systems and beam loading compensation systems synchronized to a start of beam trigger. The timing signals are based on a 650 MHz clock with manchester encoded event information and data provided over optical fiber. The timing and synchronization systems and their performance parameters will be described here.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Timing and Synchronization in the LLRF systems of the Fermilab PIP-II Linac

The PIP-II Accelerator is an 800 MeV superconducting Linac in the injection chain of the Fermilab accelerator complex. The LLRF systems for the 125 cavities which include a few normal conducting cavities in the warm front-end section, use a variety of LLRF hardware components and sub-systems that are part of the timing and synchronization system. This includes a master oscillator and phase averaging reference line, a beam pattern generator to enable beam transfer between non-harmonic RF systems and beam loading compensation systems synchronized to a start of beam trigger. The timing signals are based on a 650 MHz clock with manchester encoded event information and data provided over optical fiber. The timing and synchronization systems and their performance parameters will be described here.

Varghese, Philip↗
DOE OSTI2022

Performance in beam tests of irradiated Low Gain Avalanche Detectors for the ATLAS High Granularity Timing Detector

The High Granularity Timing Detector (HGTD) will be installed in the ATLAS detector to mitigate pile-up effects during the High Luminosity (HL) upgrade of the Large Hadron Collider (LHC) at CERN. The design of the HGTD is based on the use of Low Gain Avalanche Detectors (LGADs), with an active thickness of 50 μm, that allow to measure with high-precision the time of arrival of particles. The HGTD will improve the particle-vertex assignment by measuring the track time with a resolution ranging from approximately 30 ps at the beginning of the HL-LHC operations to 50 ps at the end. Performances of several unirradiated, as well as neutron- and proton-irradiated, LGAD sensors from different vendors have been measured in beam test campaigns during the years 2018 and 2019 at CERN SPS and DESY. This paper presents the results obtained with data recorded by an oscilloscope synchronized with a beam telescope which provides particle position information within a resolution of a few μm. Collected charge, time resolution and hit efficiency are presented. In addition to these properties, the charge uniformity is also studied as a function of the position of the incident particle inside the sensor pad.

47 OTHER INSTRUMENTATION↗
DOE OSTI2022

Injection of electron beams into two laser wakefields and generation of electron rings

Throughout this work, mutual injection of electron beams into two laser plasma wakefields was observed experimentally when driving laser pulses interfered in plasma at a small crossing angle and were slightly relatively delayed, approximately by one pulse duration. Particle-in-cell simulations revealed that the mutual injection was sensitive to the spatial overlap of the laser pulses, which therefore could be used to control the mutual injection. The dual synchronized, femtosecond electron beams are potentially useful for pump-probe experiments in ultrafast science. In addition, out-of-axis ring-shaped electron beams were detected in both experiments and simulations.

47 OTHER INSTRUMENTATION↗
DOE OSTI2024

Errant Beam Prognostics with Machine Leaning at SNS Accelerator

Particle Accelerators are complex machine with many pieces of equipment running in synchronization to deliver required beam. However, faults in particle accelerators reduce the availability of the beam for experiments affecting the overall science output. To avoid these faults, we apply anomaly detection techniques to predict any unusual behavior and perform preemptive actions to improve the total availability. Many researchers have adopted semi-supervised Machine Learning (ML) methods such as auto-encoders and variational auto-encoders for such tasks. However, supervised ML techniques designed for similarity learning such as Siamese Neural Network (SNN) can outperform semi-supervised or unsupervised methods for anomaly prediction. One of the challenges associated with application of ML models to particle accelerators is the variability in observed data over time due to system configuration changes. We employ conditional models such as Conditional Siamese Neural Networks (CSNN), and Conditional-VAE (CVAE) to learn the variability in the data by using beam configuration parameters as conditional input. We apply these models for errant beam prediction at Spallation Neutron Source accelerator under different system configurations and compare their performance. We demonstrate that CSNN outperforms CVAE in our application. This talk will present the data source, collection, analysis, data-preparation, model development, hyper-parameter studies and the results.

Rajput, Kishansingh↗