Axis 2 rf Observations [Slides]
The slides discuss the 2020 review of the Axis 2 rf observations.
43 PARTICLE ACCELERATORS↗
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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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Calculation of the longitudinal emittance dilution in a RF cavity
Dilution of the longitudinal rms emittance of a bunch passing a RF cavity is estimated for the sinusoidal dependence of the energy gain on phase and Gaussian beam distribution.
43 PARTICLE ACCELERATORS↗
A Medium Frequency RF Sensor for Detection of Magnetized Quark Nuggets
It is hypothesized that dark matter is composed of particles called quark nuggets, and further that these particles have a permanent magnetic dipole moment. If this hypothesis is true, calculations predict that a magnetized quark nugget (MQN) will oscillate when encountering the Earth's magnetosphere, and emit RF radiation between 30kHz and 30MHz. To support testing this hypothesis, a loop antenna sensor was designed and developed, which is described in this report. This sensor operates between 300kHz and 3MHz and achieves about -11dBfT/vHz sensitivity at 1.5MHz.
42 ENGINEERING↗
In situ detection of RF breakdown on microfabricated surface ion traps [Slides]
Two techniques were developed to allow users of microfabricated surface ion traps to detect RF breakdown as soon as it happens, without needing to remove devices from vacuum and look at them with a microscope.
47 OTHER INSTRUMENTATION↗
EMITTANCE GROWTH DUE TO RF PHASE NOISE IN CRAB CAVITIES
The Electron-Ion Collider (EIC) incorporates beam crabbing to recover geometric luminosity loss from the nonzero crossing angle at the interaction point (IP). It is well-known that crab cavity imperfections can cause growth of colliding beam emittances, thus degrading collider performance. Here we report a particle tracking study to quantify these effects. Presently the study is focused on crab cavity RF phase noise. Simulations were carried out using Bmad. Dependence of emittance growth on phase noise level was obtained which could be used for developing crab cavity phase control specifications. We also benchmarked these simulations with theory.
Huang, H.↗
RF Power Estimates for LAMP Drift-Tube Linac
The LANSCE Modernization Project (LAMP) concept includes a drift-tube proton linac (DTL) from 3 MeV to 100 MeV consisting of 6 tanks. This technical note provides estimates of RF power required for the LAMP DTL tanks using DTLfish modeling.
43 PARTICLE ACCELERATORS↗
Surface properties and RF performance of Vapor Diffused Nb3Sn on Nb after sequential anneals below 1000 °C
Nb3Sn is a next-generation superconducting material that can be used for future superconducting radiofrequency (SRF) accelerator cavities, promising better performance, cost reduction, and higher operating temperature than Nb. The Sn vapor diffusion method is currently the most preferred and successful technique to coat niobium cavi-ties with Nb3Sn. Among post-coating treatments to opti-mize the coating quality, higher temperature annealing without Sn is known to degrade Nb3Sn because of Sn loss. We have investigated Nb3Sn/Nb samples briefly annealed at 800-1000 °C for 10 and 20 minutes to poten-tially improve the surface to enhance the performance of Nb3Sn-coated cavities. Following the sample studies, a coated single-cell cavity was sequentially annealed at 900 °C and tested its performance each time, improving the cavity's quality factor relatively. This paper summarizes the sample studies and discusses the RF test results from sequentially annealed SRF Nb3Sn/Nb cavity.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Thermocatalytic Ethylene Production using Targeted RF Induction Heating
Ethylene, a key building block in the petrochemical industry is a top five chemical in annual production and the second highest energy consuming chemical per weight. Industrial-scale production of ethylene remains an energy consuming process and is conventionally practiced by steam cracking of ethane or naphtha feedstocks. Our project using Targeted RF Induction Heating aims to optimize the heating of the catalyst to improve energy efficiency (>50%). Induction heating also improves ethylene low-temperature yield, selectivity, and stability that will increase catalyst lifetime by >20% and result in a >15% decrease in operational costs.
Colon-Mercado, Hector R.↗
Compact Superconducting RF Accelerators for Water Treatment
Jefferson Lab is actively exploring the environmental applications of compact irradiation facilities utilizing Superconducting Radio Frequency (SRF) accelerator technology ? a well-established technology primarily used in large research machines. Recent advancements, such as the application of thin films of superconducting alloys in radio frequency (RF) resonators and the development of high-capacity cryocoolers, have made it feasible to employ this key technology in compact, standalone irradiation facilities. The main advantage over conventional systems based on normal conducting technology is the significantly enhanced efficiency in beam power generation, enabling exposure to substantially higher radiation doses. In the realm of addressing contaminants in wastewater treatment, particularly concerning persistent substances known as "forever chemicals," this technology presents an attractive solution, given the required considerable effort i.e. dose to break them down. Experiment Numbers:
Vennekate, John↗
Thermal simulation of the EIC HSR interconnect module - RF fingers
The Electron Ion Collider (EIC) Hadron Storage Ring (HSR) will reuse most of the existing superconducting magnets from the RHIC storage ring. However, the existing beam vacuum chamber and stripline BPMs will not be compatible with the planned EIC hadron bunches that will have a 3x higher intensity and be 10x shorter, and some operational scenarios with large radial offsets of the beam in the vacuum chamber. To address these challenges, a copper coated beam screen will be implemented, the existing RHIC stripline BPMs will be shielded and an interconnect module design, including new BPM will be installed adjacent to the existing BPMs. A thermal analysis of the new arc BPM interconnect housing has been conducted to assess the heating caused by beam induced resistive wall heating and electron cloud heating. An analysis of the BPM module has been made and reported separately. This report will focus on the other side of the interconnect module, containing the RF fingers.
43 PARTICLE ACCELERATORS↗
Development of Superconducting RF Cavity in Traveling-Wave Regime at Fermilab
Niobium Superconducting RF (SRF) cavities have a theoretical peak magnetic field which limits the accelerating field to 50-60 MV/m. Presently, all SRF cavities operate in a Standing Wave (SW) resonance field in which particles experience an accelerating force alternating from zero to peak. In contrast, a resonance field in Traveling Wave (TW) mode propagates along with a structure, so particles in such field can experience a constant acceleration force and could have higher energy gain than that of SW mode. This phenomenon is defined by the cavity’s transit time factor, T. A TW structure proposed in an early study achieves T ~0.9, suggesting an increase in acceleration per structure by more than 20% compared to a SW structure (T ~0.7). The early stages of developments had been funded by several SBIR grants to Euclid Techlabs and completed in collaboration with Fermilab through a 1-cell prototype and a proof-of-principle 3-cell TW cavity. It demonstrated the TW resonance excitation at room temperature in the “as-fabricated” 3-cell structure. Here we report recent progresses and the first cryogenic testing of the 3-cell TW cavity in 2 K liquid helium at Fermilab.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
RF Sources for Electron Accelerators With a focus on high-duty-factor, low-to-moderate energy architectures
A charged particle, such as an electron or a proton, is accelerated through its interaction with either a static (DC) or time-varying (RF) electric field. The magnitude of the accelerating field, or gradient, is typically given in units of volts per meter; in charged-particle accelerators, fields are usually expressed as kV/m or MV/m. The energy of the accelerated particle is usually expressed in terms of electron volts, or eV. An electron starting at rest at ground potential, and accelerated to an electrode with a potential of 1 kV, will have an energy of 1 keV.
43 PARTICLE ACCELERATORS↗
Microwave and rf Spectroscopy of 2D Carrier Systems and Bilayers (Final Technical Report)
We performed microwave spectroscopic studies of two dimensional electron systems (2DES) exhibiting the quantum Hall effect (QHE) in GaAs/Al${_x}$Ga$_{1-x}$As heterostructures. A common theme of the proposed work is electron solids, of which the simplest is the Wigner crystal, a triangular lattice of individual carriers. The solids are stabilized by carrier-carrier interaction and occur under conditions when the kinetic energy of the system is "frozen out" by high magnetic field, $B$. One of the main reasons for microwave spectroscopic study of 2DES is that the solid phases have striking microwave or rf spectra. In the low wave vector ($q$) limit these spectra exhibit a resonance that is understood as a pinning mode, a small collective oscillation of pieces of the solid within the disorder potential. Pinning modes can be very sharp, with quality factors up to around 30, and are valuable as signatures of the electron solids, and can reveal a solid even when standard dc transport shows an insulator, an integer QHE, or even a fractional QHE The pinning mode also is sensitive to the solid properties, and can reveal transitions between solids.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
RF studies at Fermilab and application to cooling
In this talk I present are our initial thoughts on potential RF studies for muon ionization channel at Fermilab.
Belomestnykh, Sergey↗
RF Digitizer for EIC LLRF
With the shutdown of Relativisitc Heavy Ion Collider (RHIC) in FY26, the former RHIC facility will be upgraded to the new Electron-Ion Collider (EIC). An RF Digitizer for the EIC LLRF system has been developed and tested on a RHIC 197 MHz cavity in Q2 2026 for a baseline per formance. Firmware and software has been developed and validated during the 197 MHz cavity test. Preliminary data from the cavity test shows phase noise performance signifi cantly better than the RHIC LLRF system.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Design and Prototyping of the 162.5 MHz PIP-II RF Reference-Line Station
The Proton Improvement Plan II (PIP-II) Reference Line distributes phase-stable radio-frequency signals so accelerating cavities transfer energy to the proton beam at the correct point in each RF cycle. The full system contains 162.5, 325, and 650 MHz sections; this project focuses on the 162.5 MHz station. Commercial filters, amplifiers, splitters, mixers, and hardware were assembled into a compact, serviceable heat-plate layout and tested to verify performance metrics at 162.5 MHz.
Subedi, Harsheet [Unlisted, US]↗
NUMERICAL CALCULATION OF LOSSES OF TRAPPED VORTICES UNDER STRONG RF MEISSNER CURRENT AND DC SUPERHEATING FIELD IN TYPE II SUPERCONDUCTORS
Research on the vortex dynamics and enhancing of superheating field in superconductors has attracted much attention in accelerator physics community to develop next-generation high-performance accelerator cavities. However, the extreme dynamics of curvilinear elastic vortices driven by very strong currents close to the depairing limit or superheating field of a superconductor with a nanostructured surface has not been well understood. We calculated the superheating field Hsh and critical momentum kc characterizing the wavelength of the instability ?m of the Meissner state to flux penetration by solving numerically the Ginzburg?Landau equations. A bulk superconductor, superconductor with the inhomogeneous surface disorder (S-S), and multilayered surface (S-I-S) have been thoroughly investigated in this work. Our result showed that S-S and S-I-S structures can enhance the superheating field well above their clean limit. In this work extensive numerical simulation of the power dissipated by an oscillating vortex segment driven by the surface ac Meissner currents was performed. Our simulations take into account the nonlinear vortex line tension, vortex mass, Bardeen?Stephen viscous vortex drag applicable at low fields, and nonlinear Larkin-Ovchinnikov (LO) viscous drag coefficient ?(v) at high fields and pinning force. We showed that the LO decrease of ?(v) with the vortex velocity v could radically change the field dependence of the surface resistance Ri(H) caused by trapped vortices. At low frequencies Ri(H) exhibits a conventional increase with H. However, as frequency increases, the surface resistance becomes a nonmonotonic function of H which decreases with H at higher fields irrespective of the pinning distribution. Overheating can mask the descending field dependence of Ri(H) as frequency increases. Our numerical simulations also show that the LO effect can cause a vortex bending instability at high field amplitudes and frequencies, giving rise to the formation of dynamic kinks along with the vortex when a vortex is pinned strongly to one end. Nonlinear losses of trapped vortices in thick films under high-amplitude RF fields as functions of frequency, mean free path and pinning characteristics have been calculated.
Pathirana, Walive↗
Autoencoder Based Analysis of RF Parameters in the Fermilab Low Energy Linac
Machine learning (ML) has the potential for significant impact on the modeling, operation, and control of particle accelerators due to its ability to model nonlinear behavior, interpolate on complicated surfaces, and adapt to system changes over time. Anomaly detection in particular has been highlighted as an area where ML can significantly impact the operation of accelerators. These algorithms work by identifying subtle behaviors of key variables prior to negative events. Efforts to apply ML to anomaly detection have largely focused on subsystems such as RF cavities, superconducting magnets, and losses in rings. However, dedicated efforts to understand how to apply ML for anomaly detection in linear accelerators have been limited. In this paper the use of autoencoders is explored to identify anomalous behavior in measured data from the Fermilab low-energy linear accelerator.
Edelen, Jonathan P. (ORCID:0000000215180652)↗