Moment constraints in beams with discrete and continuous rotational symmetry
Not Available
43 PARTICLE ACCELERATORS↗
SEARCH · Engineering Papers
Results for “Proton & ion sources”
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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Laser-plasma ion beam booster based on hollow-channel magnetic vortex acceleration
Laser-driven ion acceleration provides ultrashort, high-charge, low-emittance beams, which are desirable for a wide range of high-impact applications. Yet after decades of research, a significant increase in maximum ion energy is still needed. This paper introduces a quality-preserving staging concept for ultraintense ion bunches that is seamlessly applicable from the nonrelativistic plasma source to the relativistic regime. Full three-dimensional particle-in-cell simulations prove robustness and capture of a high-charge proton bunch, suitable for readily available and near-term laser facilities.
43 PARTICLE ACCELERATORS↗
Exotic particles at the DUNE near detector from charged pion scattering
Fixed-target proton-beam experiments produce a multitude of charged pions that rescatter in the beam dump. These charged pion scattering events can be an additional irreducible source of exotic particles which couple to photons or hadrons. We analyze the sensitivity of the DUNE near detector complex to millicharged particles (MCPs) and heavy axionlike particles (ALPs) with low-energy couplings to gluons. Using the framework of chiral perturbation theory, we demonstrate regimes of parameter space where the charged pion production channel dominates over previously considered production mechanisms for both MCPs and ALPs, thereby improving the sensitivity of DUNE to these new particles compared to previous studies. Published by the American Physical Society 2024
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Realizing the scientific program with polarized ion beams at the future BNL Electron Ion Collider
Polarized ion beams at the Electron Ion Collider (EIC) are essential to address some of the most important open questions at the twenty-first century frontiers of understanding of the fundamental structure of matter. Here, in this work, we summarize the science case and identify polarized 2 H, 3 He, 6 Li, and 7 Li ion beams as critical technology that will enable experiments which address the most important science. Furthermore, we discuss the required ion polarimetry and spin manipulation at the EIC. The current EIC accelerator design is presented. We identify a significant research and development effort across national and international laboratories and universities that is required over about a decade to realize the polarized ion beams and estimate (based on previous experience) that it will require about 20 full-time equivalent (FTE) over 10 years (or a total of about 200 FTE-years) of personnel, including graduate students, postdoctoral researchers, technicians, and engineers. Attracting, educating, and training a new generation of physicists in experimental spin techniques will be essential for the successful realization. Artificial intelligence and machine learning are seen as having significant potential for both acceleration of research and development and amplification of discovery in the optimal realization of this unique quantum technology on a cutting-edge collider. The research and development effort is synergistic with research in atomic physics and fusion energy science.
43 PARTICLE ACCELERATORS↗
Customized Bayesian optimization for efficient beam tuning at the facility for rare isotope beams
Bayesian optimization (BO) has recently emerged as a powerful approach for on-line beam tuning, and it is rapidly gaining adoption across accelerator facilities due to its flexibility and efficiency in handling complex optimization tasks. At the Facility for Rare Isotope Beams, rapid and reliable tuning is essential to support the delivery of diverse ion species. To improve the practicality of BO in this setting, we implemented several enhancements, including scalarized composite objective construction for multicriteria optimization, asynchronous evaluation for better resource utilization, prior-mean-assisted optimization to accelerate convergence, and a local search strategy for rapid completion of the task. We present the details of these methods, discuss challenges-encountered, and share our experience applying them to specific beam-tuning tasks.
Accelerators & storage rings↗
New constraints on ALP couplings to electrons and photons from ArgoNeuT and the MiniBooNE beam dump
Not Available
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Observations of heavy energetic ions far upstream from Comet Halley
On March 25, 1986, when the ICE spacecraft came within 28 million km of the nucleus of comet Halley, and for several days around this time, bursts of heavy ions were observed by the ICE energetic ion experiment. The bursts were observed only during periods when the solar wind velocity was considerably higher than its nominal value. The characteristics of these ions, in particular their anisotropies, were examined. Using the well known formulae for transformation of distributions from the solar wind frame of reference to the spacecraft frame, the angular distributions expected from either protons, or heavy ions from the water group, were studied, showing that the measurements are consistent with heavy ions, and not with protons. Other sources of heavy ions are considered, and the most likely source of these ions is comet Halley.
Sanderson, T. R.↗
Cassini Observations of Saturn's Dawn-Magnetotail Region and their Relation to Models of Saturn's Aurora: Preliminary Results
Using Cassini plasma and magnetic field observations from the dawn meridian of Saturn s outer magnetosphere to Saturn s magnetotail region, we investigate the applicability of the centrifugal instability model by Sittler et al. [2006] for Saturn s auroral response to the solar wind, versus the reconnection model of Saturn s aurora by Cowley et al. [2005]. We use Cassini Plasma Spectrometer (CAPS) Ion Mass Spectrometer (IMS) and Electron Plasma Spectrometer (ELS) observations to characterize the plasma environment. ELS and magnetometer observations are used to map out the morphology of the outer magnetosphere from dawn to midnight local time. IMS observations are used to measure plasma flow velocities from which one can infer rotation versus convective flows. IMS composition measurements are used to trace the source of plasma from the inner magnetosphere (protons, H2 and water group ions) versus an external solar wind source (protons and Heff ions). A critical parameter for both models is the strength of the convection electric field with respect to the rotational electric field for the large scale magnetosphere. Is there a significant return flow from the magnetotail? Pitch angle distributions also play an important role as a discriminator. If the magnetosphere tends to conserve angular momentum as suggested by Sittler et al. [2006], then we expect to see an anti-correlation between rotational flow component and radial flow velocities. All will be investigated.
Sittler, E. C.↗
Cassini Observations of Saturn's Dawn-Magnetotail Region: Preliminary Results
Using Cassini thermal plasma, hot plasma and magnetic field observations for several intervals between the dawn meridian of Saturn's outer magnetosphere and Saturn's magnetotail region, we investigate the structure of the magnetotail, plasma and magnetic field properties within tail-like current sheet regions and ion flows within the dawn to magnetotail regions. We use Cassini Plasma Spectrometer (CAPS) Ion Mass Spectrometer (IMS) and Electron Plasma Spectrometer (ELS) observations and MIMI LEMMS ion and electron observations to characterize the plasma environment. LMS observations are used to measure plasma flow velocities from which one can infer rotation versus convective flows. IMS composition measurements are used to trace the, source of plasma from the inner magnetosphere (protons, H(2+) and water group ions) versus an external solar wind source (protons and He++ ions). A critical parameter for both models is the strength of the convection electric field with respect to the rotational electric field for the large scale magnetosphere. For example, are there significant return flows (i.e., negative radial velocities, V(sub R) < 0) and/or plasmoids (V(sub R) > 0) within the magnetotail region?
Sittler, Edward C.↗
Performance Optimization of the IOTA Duoplasmatron Proton Source
We present results from online optimization studies of a duoplasmatron ion source designed to produce 50~keV protons for acceleration to 2.5~MeV and subsequent injection into the Integrable Optics Test Accelerator (IOTA) at Fermilab. Using a Bayesian exploration technique, we developed multi-parameter models of the source s proton current and employed these models to optimize its performance. Depending on the spectrometer configuration used to isolate the proton beam and the chosen optimization objective, we identified three candidate operating points, achieving normalized 50~\% emittances between 0.57 and 1.3~\textmu m and a maximum proton current of $14.5 \pm 0.6$~mA.
Banerjee, Nilanjan [Fermilab] (ORCID:0000000344660↗
Cassini Observations of Saturn's Magnetotail Region: Preliminary Results
Using Cassini thermal plasma, hot plasma and magnetic field observations for several intervals between the dawn meridian of Saturn's outer magnetosphere and Saturn's magnetotail region, we investigate the structure of the magnetotail, plasma and magnetic field properties within tail-like current sheet regions and ion flows within the magnetotail regions. We use Cassini Plasma Spectrometer (CAPS) Ion Mass Spectrometer (IMS), Electron Plasma Spectrometer (ELS) observations, MIMI LEMMS ion and electron observations and Cassini magnetometer data (MAG) to characterize the plasma environment. IMS observations are used to measure plasma flow velocities from which one can infer rotation versus convective flows. IMS composition measurements are used to trace the source of plasma from the inner magnetosphere (protons, H2+ and water group ions) versus an external solar wind source (protons and ~ e +i+on s). A critical parameter for both models is the strength of the convection electric field with respect to the rotational electric field for the large scale magnetosphere. For example, are there significant return flows (i.e., negative radial velocities, VR < 0) and/or plasmoids (V(sub R) > 0) within the magnetotail region? Initial preliminary evidence of such out flows and return flows was presented by Sittler et al. This talk complements the more global analysis by McAndrews et al.
Sittler, E. C.↗
Plasma-dominated magnetic field configurations for the magnetosphere of Uranus
There is significant indirect evidence that the planet Uranus possesses a magnetic field. This evidence is based on the observation of hydrogen Lyman alpha emission from Uranus with the aid of the International Ultraviolet Explorer (IUE) spacecraft. The detection of water ice on the Uranian moons led Cheng (1984) to suggest that charged particle sputtering of the icy satellites could provide a significant internal source of oxygen ions and protons to the Uranian magnetosphere. Cheng concluded that this mechanism would predict aurorae around both magnetic poles of Uranus. Cheng's idea of the presence of a continuous internal plasma supply to the Uranian magnetosphere is further pursued in the present investigation. Questions are considered regarding the evolution of Uranus' magnetosphere from a vacuum configuration toward a plasma pressure dominated equilibrium configuration, taking into account the amount of the thermal plasma pressure as a free parameter.
Ip, A. K.↗
Neutron generator based on intense lithium beam driver
We are proposing a compact neutron generator based on a Li beam driver. The proposed neutron generator comprises a laser ion source, a radio-frequency quadrupole linear accelerator (RFQ linac), a drift tube linac, and a target containing protons. In the generator, the lithium ion is used as a projectile instead of protons to utilize the kinematic focusing technique. The technique enables us to enhance the neutron flux without increasing the beam energy, which is important to develop a clean compact neutron generator. Moreover, the combination of a laser ion source and a RFQ linac with the direct plasma injection scheme will provide several tens of mA of a fully ionized lithium beam, which is much higher than that of conventional heavy ion sources comparable with proton drivers. Neutrons are generated by the nuclear reaction of the lithium ions and protons in the beam target. In this paper, we reported the current status of the development. For RFQ, we designed the RFQ rods to accelerate 40 mA of 7Li3+. We fabricated and installed the rods into a cavity, and, as a first test, accelerated 10 mA of C6+ successfully.
Ikeda, Shunsuke (ORCID:0000000339800577)↗
Online charge measurement for petawatt laser-driven ion acceleration
Laser-driven ion beams have gained considerable attention for their potential use in multidisciplinary research and technology. Preclinical studies into their radiobiological effectiveness have established the prospect of using laser-driven ion beams for radiotherapy. In particular, research into the beneficial effects of ultrahigh instantaneous dose rates is enabled by the high ion bunch charge and uniquely short bunch lengths present for laser-driven ion beams. Such studies require reliable, online dosimetry methods to monitor the bunch charge for every laser shot to ensure that the prescribed dose is accurately applied to the biological sample. In this paper, we present the first successful use of an Integrating Current Transformer (ICT) for laser-driven ion accelerators. This is a noninvasive diagnostic to measure the charge of the accelerated ion bunch. It enables online estimates of the applied dose in radiobiological experiments and facilitates ion beam tuning, in particular, optimization of the laser ion source, and alignment of the proton transport beamline. We present the ICT implementation and the correlation with other diagnostics, such as radiochromic films, a Thomson parabola spectrometer, and a scintillator.
47 OTHER INSTRUMENTATION↗
Negative hydrogen ion sources for particle accelerators: Sustainability issues and recent improvements in long-term operations
High brightness, negative hydrogen ion sources are used extensively in scientific facilities operating worldwide. Negative hydrogen beams have become the preferred means of filling circular accelerators and storage rings as well as enabling efficient extraction from cyclotrons. Several well-known facilities now have considerable experience with operating a variety of sources such as RF-, filament-, magnetron- and Penning-type H- ion sources. These facilities include the US Spallation Neutron Source (SNS), Japan Proton Accelerator Research Complex (J-PARC), Rutherford Appleton Laboratory (RAL-ISIS), Los Alamos Neutron Science Center (LANSCE), Fermi National Accelerator Laboratory (FNAL), Brookhaven National Laboratory (BNL), numerous installations of D-Pace (licenced by TRIUMF) ion sources used mainly on cyclotrons and, most recently, the CERN-LINAC-1 injector. This report first summarizes the current performance of these ion sources in routine, daily operations with attention toward source service-periods and availability metrics. Sustainability issues encountered at each facility are also reported and categorized to identify areas of common concern and key issues. Recent ion source improvements to address these issues are also discussed as well as plans for meeting future facility upgrade requirements.
Welton, Robert F.↗
Modeling of tungsten filament in gas discharge in H - ion source
Sources of negative ions such as H - are essential elements of proton accelerators and tokamaks. They have limited lifetime. The replacement of an ion source is a costly process causing delays in the operation of the entire machine. The hot tungsten filament is the key element that limits the lifetime of the H - ion source at the Los Alamos Neutron Science Center (LANSCE) facility. An accurate model, which describes the filament physics and provides a reliable estimate on its lifetime, may significantly improve the operation of the facility. In this report we describe such a model, including a comprehensive list of relevant physical processes from first principles. The model can be used to describe different regimes of operation using diagnostics data as input parameters. It has been benchmarked against the data collected during the production cycle at LANSCE and shows good agreement with experimental data.
47 OTHER INSTRUMENTATION↗
Light Ion Double-Differential Cross Section Parameterization and Results from the SHIELD Transport Code
Light ions and neutrons have been shown to make large contributions to space radiation dose equivalent for realistic shielding scenarios. Efficient and accurate calculations of light ion double-differential cross sections are required for input into space radiation transport codes. A thermal proton cross section model is developed which includes proton production from the three sources of projectile, central fireball, and target. It is shown that this three-source model is able to explain the low momentum shoulder seen in proton spectra. Using the coalescence model, the thermal proton model is used to calculate light ion double-differential cross sections employed in space radiation transport codes. The three-source model is also seen to be essential to explain the light ion shoulders, which are even more pronounced than the proton shoulders. Comparisons are also made to the cross section models used in the SHIELD transport code.
Space radiation↗
Light Ion Double-Differential Cross Sections for Space Radiation
Neutrons and light ions have been shown to make large contributions to space radiation dose equivalent for realistic shielding scenarios. However, there are considerable uncertainties in the calculation of light ion production. Efficient and accurate calculation of light ion double-differential cross sections are required for input into space radiation transport codes. A thermal proton cross section model is developed which includes proton production from the 3 sources of projectile, central fireball, and target. It is shown that this 3-source model is able to explain the low-momentum, small-angle shoulder seen in proton spectra. Using the coalescence model, the thermal proton model is used to calculate light ion double-differential cross sections for use in space radiation transport codes. The 3-source model is also seen to be essential to explain the light ion shoulders, which are even more pronounced than the proton shoulders. Extensive comparisons between models and experimental measurements are shown and necessary future work is discussed.
Norbury, John W.↗