An ion cloud confined in a Paul trap eventually reaches a Coulomb crystalline state when strongly cooled toward absolute zero. The normalized emittance of the Coulomb crystal can be in the sub-femtometer range. The trap is thus usable as a unique ion source for nano-beam production, though the available beam intensity is limited. This new concept was first discussed nearly 20 years ago* and later experimentally demonstrated by several research groups (**, ***). In this paper, we report on the result of a recent experiment where an attempt was made to extract Ca+ or N2+ ions one by one from a compact linear Paul trap. In addition to the regular extraction scheme based on a string Coulomb crystal, the possibility of using a multi-shell crystalline structure is explored in detail.

Laser-driven ion accelerators (LDIAs) are well-suited for radiobiological research on ultra-high dose rate effects due to their high intensity. For this application, a transport system is required to deliver the desired beam intensity and dose distribution while online dosimetry is required due to the inherent shot-to-shot variability of LDIAs. At the BELLA Center's iP2 beamline, we implemented two compact, permanent magnet-based beam transport configurations for delivering 10 or 30 MeV protons to a biological sample, along with a suite of diagnostics used for dosimetry. These diagnostics include multiple integrating current transformers (ICTs) for indirect online dose measurements and calibrated radiochromic films (RCFs) to measure the dose profile and calibrate the ICT dosimetry. Benchmarked Monte-Carlo (MC) simulations of the beamline allow us to predict the dose received by the sample and correct the linear energy transfer (LET)-dependent response of the RCFs. This work not only further establishes the practicality of utilizing LDIAs for radiobiological research but also highlights the BELLA Center's capacity to accommodate further experiments in this domain.

Laser Doppler cooled ion traps can produce stationary bunches of ions with extremely low velocity spread (0.6 m/s RMS) and emittance (10e-13 m normalized). This corresponds to temperatures of a few milli-Kelvin and allows the ions to settle into a fixed lattice analogous to a solid crystal, but with the Coulomb repulsion balanced by the trapping force, rather than a chemical bond. Extraction of such a bunch into a beamline could provide a new regime of ultra-low emittance beams if the emittance is preserved through the extraction operation. This paper shows that extraction from the ion trap and initial acceleration does not cause drastic growth, thus preserving the ultra-low emittance nature of the bunch. Techniques for compensating coherent 'emittance growth' effects such as nonlinear bunch distortion are also investigated.

A liquid lithium target system is being developed for laser ion sources. Existing laser ion sources are operated at the repetition rate of the order of 1 Hz. The limitation stems from the use of solid laser targets because of the craters created and the need to provide a fresh surface by either repositioning the laser beam or the target. In addition, an enormously large surface area is needed for long-term operation. This limits the total yield of lithium ions and the application of laser ion sources. To dramatically increase the repetition rate, we propose the use of a liquid lithium target in a crucible because a liquid surface shape is recovered by itself after laser irradiation. The establishment of a liquid target system is an important objective for the development of the intense lithium beam driver for a clean compact source of a directional neutron beam. In the conference, the concept and design of experimental apparatus for the development will be presented.

We are researching the development of an ultra-high intensity heavy ion source based on laser ablation ion source (LIS) technology coupled with a unique beam injection technique called Direct Plasma Injection Scheme (DPIS). A metallic target is ablated using a Q-switched Nd:YAG laser to generate a pulsed high-density plasma, which is then injected and accelerated by a radio-frequency quadrupole (RFQ) linear accelerator. The ion source enables the production of rare isotopes, the use of particle beams in cancer treatment, and nuclear physics experiments. The exploration of multiple charge states for Mg production is currently underway. The measurement of beam current is conducted using a Faraday cup positioned at the end of the beam line. Following the RFQ acceleration, the beam is transported by multiple quadrupole magnets and a steerer, and a dipole magnet then directs the beamline into the Faraday cup. Notably, we have accomplished an ion beam current of about 20 mA for Mg10+ ions and a current exceeding 10 mA for fully stripped Mg12+ ions. In this presentation, I will discuss the operation of the LIS at Brookhaven National Laboratory (BNL) and the outcomes of Mg ion production.

Many of ion beams generated by the Electron Cyclotron Resonance Ion Source (ECRIS) originate from solid-state materials and undergo a conversion process to transition from a solid to a gaseous state before being introduced into the plasma. Established techniques for thermal evaporation encompass ovens and others. The primary objective is to advance oven technology targeting increased reliability, durability, efficiency, and an expanded temperature range. At the Facility for Rare Isotope Beams (FRIB), a specialized inductive High Temperature Oven (HTO) has been developed to ensure the consistent and reliable production of metallic ion beams. ANSYS simulations have been carried out to maximize the temperature inside the oven and to help select the materials used with the oven based on the analysis on the heat distribution. Off-line tests have shown that the oven operates durably at temperatures close to 2000°C, and on-line tests already demonstrated beam intensity as high as 52 eµA of 238U35+ and 60 eµA of 238U33+. This paper presents and discusses the design features, ANSYS simulations, off-line and on-line test results of the HTO.

An ion cloud confined in a Paul trap eventually reaches a Coulomb crystalline state when strongly cooled toward absolute zero. The normalized emittance of the Coulomb crystal can be in the sub-femtometer range. The trap is thus usable as a unique ion source for nano-beam production, though the available beam intensity is limited. This new concept was first discussed nearly 20 years ago* and later experimentally demonstrated by several research groups (**, ***). In this paper, we report on the result of a recent experiment where an attempt was made to extract Ca+ or N2+ ions one by one from a compact linear Paul trap. In addition to the regular extraction scheme based on a string Coulomb crystal, the possibility of using a multi-shell crystalline structure is explored in detail.

Laser-driven ion accelerators (LDIAs) are well-suited for radiobiological research on ultra-high dose rate effects due to their high intensity. For this application, a transport system is required to deliver the desired beam intensity and dose distribution while online dosimetry is required due to the inherent shot-to-shot variability of LDIAs. At the BELLA Center's iP2 beamline, we implemented two compact, permanent magnet-based beam transport configurations for delivering 10 or 30 MeV protons to a biological sample, along with a suite of diagnostics used for dosimetry. These diagnostics include multiple integrating current transformers (ICTs) for indirect online dose measurements and calibrated radiochromic films (RCFs) to measure the dose profile and calibrate the ICT dosimetry. Benchmarked Monte-Carlo (MC) simulations of the beamline allow us to predict the dose received by the sample and correct the linear energy transfer (LET)-dependent response of the RCFs. This work not only further establishes the practicality of utilizing LDIAs for radiobiological research but also highlights the BELLA Center's capacity to accommodate further experiments in this domain.

Ion beams from laser-driven plasma sources can provide ultra-short (10s of fs for 10s of MeV), ultra-low slice emittance (10s of nm), and high-charge (100s of pC) properties. Demonstrated maximum energies for laser-ion sources are just short of those needed for pivotal applications, such as proton tumor therapy. Here, a robust and energy-scalable concept is presented that could boost the energy of an ultra-intense ion bunch through multiple stages to 100s of MeV/u and even towards the relativistic regime, using identical plasma booster stages based on magnetic vortex acceleration. Electromagnetic, full-3D particle-in-cell simulations are used to demonstrate the capability to capture, accelerate, and preserve the quality of a high-charge (200 pC), 20 nm emittance proton bunch, where both source and booster stages could be realized with capabilities of existing laser facilities.

Plasma temperature dynamics provide significant insight when evaluating ion source performance. Quantities such as beam emittance, or mean transverse energy, are strongly correlated with the source plasma temperature. At LANSCE there is currently no method implemented for measuring initial source emittance or implementing tunability of mean transverse energy through ion source control parameters. In this work we will discuss our demonstration of a new laser diagnostic tool for measuring H- beam emittance on the LANSCE H- ion source laser diagnostic stand. Our investigated method will be an extension of systems outlined for NIFS, and will be optimized for rapid response times, scanning the Doppler broadened Hydrogen-alpha emission line at a rate 10x faster than the plasma ignition time window (800 microseconds). We will show that our real-time, non-intrusive measurement approach will enable characterization and study of source control parameter effects on source plasma temperature for future emittance optimization.

Numerical modeling of low-temperature plasma (LTP) ion sources provides cost-effective techniques for developing and optimizing beam characteristics for ion implantation and other applications, including plasma processing and etching. Particle-in-cell (PIC) models are a powerful tool for simulating plasma formation and dynamics in LTP sources. Beam formation and transport of the beam through extraction optics can benefit from reduced physical models. One can couple a PIC model for plasma chambers with a different transport model in the extraction region. However, this coupling is ad hoc, and it is often not clear that the models are physically consistent with each other. We present an integrated modeling capability that couples plasma chamber modeling with beam formation using the VSim computational framework. We leverage advanced modeling techniques such as energy-conserving PIC and variable meshing to improve simulation performance. We present results for modeling and optimization of beams for ion implantation. Our results show that our integrated models can improve optimization of beam currents, beam uniformity, and emittance for LTP ion sources.