Heavy Ion Facility Research Articles

Preliminary Design of Superconducting Gantry Magnet for Miniaturized Heavy-Ion Facility

Preliminary Design of Superconducting Gantry Magnet for Miniaturized Heavy-Ion Facility

Conserved number fluctuations under global rotation in a hadron resonance gas model

Net-baryon number, net-charge and net-strangeness fluctuations measured in ultra-relativistic heavy-ion collisions may reveal details and insights into the quark-hadron transition, hadrochemical freeze-out and possibly aid in the search of the QCD critical point. By scanning in collision energy, current and upcoming heavy-ion facilities aim to explore the finite density regime where the critical point may lie. Effects due to rotation are also expected in case of peripheral collisions and we report on conserved number susceptibilities as calculated in the hadron resonance gas model augmented by a global angular velocity. Since these quantities are directly related to the experimentally measurable moments of the corresponding distributions our results show the possible impact of vorticity on the theoretical baseline and should be useful for referencing with experimental data and QCD-based calculations.

Extending deterministic transport capabilities for very-high and ultra-high energy electron beams

Focused Very-High Energy Electron (VHEE, 50–300 MeV) and Ultra-High Energy Electron (UHEE, > 300 MeV) beams can accurately target both large and deeply seated human tumors with high sparing properties, while avoiding the spatial requirements and cost of proton and heavy ion facilities. Advanced testing phases are underway at the CLEAR facilities at CERN (Switzerland), NLCTA at Stanford (USA), and SPARC at INFN (Italy), aiming to accelerate the transition to clinical application. Currently, Monte Carlo (MC) transport is the sole paradigm supporting preclinical trials and imminent clinical deployment. In this paper, we propose an alternative: the first extension of the nuclear-reactor deterministic chain Njoy-Dragon for VHEE and UHEE applications. We have extended the Boltzmann-Fokker-Planck (BFP) multigroup formalism and validated it using standard radio-oncology benchmarks, complex assemblies with a wide range of atomic numbers, and comprehensive irradiation of the entire periodic table. 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By irradiating the entire periodic table, we observed similar performance between lithium (Z=3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Z=3$$\\end{document}) and cerium (Z=58\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Z=58$$\\end{document}). Deficiencies observed between praseodymium (Z=59\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Z=59$$\\end{document}) and einsteinium (Z=99\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Z=99$$\\end{document}) have been reported, analyzed, and quantified, offering critical insights for the ongoing development of the Evaluated Nuclear Data File mode in Njoy.

Cryogenic distribution system design for cryomodules and cavities test in HIAF project

ABSTRACT High-intensity heavy-ion accelerator facility (HIAF) is an accelerator-driven high-current heavy ion facility, currently under construction in Guangdong, China. The proton linear accelerator of HIAF linac has 96 superconducting cavities and 17 cryomodules cooled by 2 K saturated superfluid helium. Cryogenic tests should be carried out in a test cryogenic system prior to the online operation of each cavity and cryomodule. The cryogenic distribution system (CDS) is the main part of the test cryogenic system, which is used for transporting cryogenic fluid between helium refrigerator and test terminals. A specific CDS is developed due to the long cryogenic test time. Each test terminal can be independently cooled and heated up, saving quite a bit of time without impacting the others. This article provides comprehensive explanations for the process design, process analysis, and special structure design which enhance the system’s maintainability. Furthermore, particular technical designs, such as measuring system, helium guard, and elimination of thermoacoustic oscillations, are described in detail.

Design and characterization of multichannel front-end electronics for detectors at HIRFL and HIAF

A multichannel front-end readout electronics (MFEE) has been designed for readout in detectors in the heavy ion facility in Lanzhou (HIRFL) and the high-intensity heavy-ion accelerator facility (HIAF). With 40 different adjustable gains, this MFEE can meet the need for most of the experiment. One MFEE can read and process the output signals of 128 channels of a detector at the same time. MFEE is based on the AD8488 chip and uses Xilinx Kintex 7 series FPGA, combined with the periphery circuits design, to complete the detector's output charge signal readout. This paper will discuss the design and performance of the MFEE.

Heavy Ion Energy Deposition and SEE Intercomparison Within the RADNEXT Irradiation Facility Network

RADNEXT is an EU-funded network of irradiation facilities and radiation effects experts aimed at increasing the quantity and quality of user access to accelerator infrastructure, and improving the diversity and harmonization across facilities. Along with the beam provision to worldwide radiation effects users, RADNEXT has an ambitious research program oriented at improving radiation effects testing, of which an example of a heavy ion facility inter-comparison at very different energy regimes is included in this work. In particular, energy deposition distributions in a silicon solid-state detector and the Single Event Upset (SEU) and Multiple Cell Upset (MCU) behaviour are compared amongst heavy ion beams of similar LET, but very different energies (i.e., from the more classical ~10 MeV/u regime up to several hundreds of MeV/u).

Design of a compact superconducting accelerator for advanced heavy-ion therapy

Radiotherapy using energetic carbon beams from the Heavy Ion Medical Accelerator in Chiba (HIMAC) has been carried out at the National Institutes of Quantum Science and Technology (QST) since June 1994. Based on positive clinical results, carbon-ion radiotherapy was authorized as an Advanced Medical Technology by Japanese government from 2003 and it was subsequently approved for inclusion in the Japanese National Health Insurance system from 2016. For the widespread use of carbon-ion radiotherapy, design studies as well as related research and development projects were conducted to develop a compact accelerator facility from 2004. Based on these studies, five compact facilities were constructed in Japan. However, since the accelerators are large in size, construction of these facilities is currently limited to university hospitals or large medical centers, and hence development of a more compact accelerator is desired. To further promote widespread proliferation of heavy-ion facilities and concurrently to maximize the potential of heavy-ion therapy, a project to develop a compact superconducting accelerator, the Quantum Scalpel project, was proposed. The compact accelerator employs superconducting technology to reduce the footprint of the entire accelerator system and the accelerator can provide various therapeutic beams of helium, carbon, oxygen, and neon ions having the energy of 56-430 MeV/u to advanced heavy-ion therapy. In this article, we report the design of the compact superconducting accelerator for the advanced heavy-ion therapy and describe the progress of related research and development projects.

Beam optics study for a potential VHEE beam delivery system

VHEE (Very High Energy Electron) therapy can be superior to conventional radiotherapy for the treatment of deep seated tumours, whilst not necessarily requiring the space and cost of proton or heavy ion facilities. Developments in high gradient RF technology have allowed electrons to be accelerated to VHEE energies in a compact space, meaning that treatment could be possible with a shorter linac. A crucial component of VHEE treatment is the transfer of the beam from accelerator to patient. This is required to magnify the beam to cover the transverse extent of the tumour, whilst ensuring a uniform beam distribution. Two principle methodologies for the design of a compact transfer line are presented. The first of these is based upon a quadrupole lattice and optical magnification of beam size. A minimisation algorithm is used to enforce certain criteria on the beam distribution at the patient, defining the lattice through an automated routine. Separately, a dual scattering-foil based system is also presented, which uses similar algorithms for the optimisation of the foil geometry in order to achieve the desired beam shape at the patient location.

Study on occupational exposure of medical staff caused by induced radioactivity in the treatment room of medical heavy-ion facility

Heavy-ion radiotherapy is currently recognized as the most advanced particle therapy method and is being vigorously promoted and applied worldwide. This method can rapidly generate radiation and induce radioactivity during treatment. However, the induced radioactivity, which is the primary source of exposure for medical staff, does not disappear following therapeutic application in the treatment room. In this study, we investigated the characteristics, dose rate distribution, and impact of this induced radioactivity on medical staff in the treatment room (uniform scanning mode) at Gansu Wuwei Tumor Hospital using experimental measurement and Monte Carlo simulation. We found that the exposure dose experienced by medical staff is predominantly related to the irradiated patients for single irradiation and the irradiated beam delivery system for long-term irradiation. The half-lives of the main radionuclides ranged from a few minutes to tens of minutes for single irradiation and from tens of days to hundreds of days for long-term irradiation. The primary radionuclide contributors are 15O, 11C, 176Ta, and 177W. We also estimated the personal dose experienced by the medical staff in the treatment room in relation to their working patterns. The results showed that the maximum annual exposure dose of medical staff in the horizontal treatment direction under the current model was 0.728 mSv. We hypothesized that an appropriate increase in the patient's treatment could reduce the annual exposure dose of medical staff to 0.650 mSv without changing the total treatment time per day. Finally, some suggestions were made to reduce the exposure of medical staff to unwanted radiation.

High Performance 18 GHz ECR Ion Sources Development

At present, ECR ion sources are developing towards higher frequency, higher magnetic field technology. However, 18 GHz is the highest optimal operation microwave frequency for room temperature ECR ion sources, which can meet the needs of most of the existing heavy ion facilities. After the success of the 18 GHz ECR ion source LECR4, we developed the upgraded version source LECR5 aiming for higher beam intensity and higher charge state ions. With a higher radial field, bigger plasma chamber volume, longer mirror length, and flexible Bmm field, promising results have been made at the power level of ∼2.1 kW@18 GHz, for instance, 81 eμA Bi32+, and 22 eμA Bi41+. This ion source has been recently used for the heavy ion facility SESRI (Space Environment Simulation Research Infrastructure) as the pre-injector ion source. High beam intensities and reasonable beam qualities have been demonstrated during the test platform. Inspired by this outcome, a hybrid 18 GHz ion source called HECRAL has been proposed aiming for the similar performance of SECRAL at 18 GHz. This paper will present the recent update of the LECR5 ion source commissioning. The design and preliminary results of the HECRAL ion source will be described.

The CDAU — a common data acquisition unit for the radiation imaging detectors at HIRFL-CSR

A common data acquisition unit (CDAU) has been designed for data transmission in the radiation imaging detectors in the Heavy Ion Facility in Lanzhou (HIRFL). With a bandwidth of 64 Gbps, this CDAU can meet the need for most of the experiment. The CDAU can connect four front-end readout cards (FECs) through optical links for data collection, packaging, and transmission. This CDAU is based on the PCI Express (PCIe) Gen3 bus, using Xilinx Kintex Ultrascale series FPGA, combined with the periphery circuits design to complete the data acquisition system. This paper will discuss the design and performance of the CDAU.

Physics and biomedical challenges of cancer therapy with accelerated heavy ions.

Radiotherapy should have low toxicity in the entrance channel (normal tissue) and be very effective in cell killing in the target region (tumour). In this regard, ions heavier than protons have both physical and radiobiological advantages over conventional X-rays. Carbon ions represent an excellent combination of physical and biological advantages. There are a dozen carbon-ion clinical centres in Europe and Asia, and more under construction or at the planning stage, including the first in the USA. Clinical results from Japan and Germany are promising, but a heated debate on the cost-effectiveness is ongoing in the clinical community, owing to the larger footprint and greater expense of heavy ion facilities compared with proton therapy centres. We review here the physical basis and the clinical data with carbon ions and the use of different ions, such as helium and oxygen. Research towards smaller and cheaper machines with more effective beam delivery is necessary to make particle therapy affordable. The potential of heavy ions has not been fully exploited in clinics and, rather than there being a single 'silver bullet', different particles and their combination can provide a breakthrough in radiotherapy treatments in specific cases.

Measurement of therapeutic 12C beam in a water phantom using CR-39

The motivation for this study was to explore a new method to test the particle spatial distribution for a therapeutic carbon beam. CR-39 plastic nuclear track detectors were irradiated to a 276.5 MeV u−1 mono-energy carbon beam at the heavy ion facility in the Shanghai Proton and Heavy Ion Center. The spatial distribution of the primary carbon beam and secondary fragments in a water phantom were systematically analyzed both in the transverse direction (perpendicular to the projection direction of the primary beam) and at different depths in the longitudinal direction (along the projection direction of the primary beam) with measured tracks on the CR-39 detectors. Meanwhile, the theoretically spatial distribution and linear energy transfer (LET) spectra of the primary beam and secondary fragments were calculated using the Monte Carlo (MC) toolkit Geant4. The results showed that the CR-39 detectors are capable of providing high lateral resolution of carbon ion at different depths. In the range of the primary carbon beam, the beam width simulated with MC is in good agreement with that of experimental measurement. The track size registered in the CR-39 has a good correlation with the particle LET. These findings indicate that the CR-39 can be used for measuring both the particle flux and its spatial distribution of carbon ions.

Analysis of Key Points of Radiation Sources in Proton and Carbon Ion Radiotherapy Facilities in Shanghai

Compared with conventional high energy X-ray radiotherapy, proton/carbon ion has obvious advantages because of its Bragg peak dose distribution. However, proton heavy ion facility has complex structure, high energy and various radiation types due to various nuclear reaction processes, the radiation protection safety brought by the operation of facilities has gradually attracted attention. Taking the proton/carbon ion radiotherapy facility of Shanghai Proton and Heavy Ion Center as an example, the author mainly analyzed the operation principle of proton/carbon ion treatment facility, the basis of radiation protection, analysis of key radiation source points, etc., so as to provide theoretical support and experience for radiation protection.

Development of a GEM-based time projection chamber prototype for low-energy rare-isotope beam experiments

In this study, we developed a time projection chamber (TPC) prototype with gas electron multipliers (GEM) to evaluate the basic performance of the GEM-based TPC for the rare-isotope beam experiments to be conducted at the RAON heavy-ion facility. The TPC prototype has a drift volume of 10×10×15 cm3, and we operated it in an Ar/CH4 gas mixture (90/10). The TPC data acquisition system collected 256 pad signals in full-readout mode using cosmic-ray muons and α particles from an 241Am source. The measured spatial resolutions on the pad plane and along the drift direction were 350μm and 250μm, respectively. We also discussed the tracking performance of the future active target TPC with a 20 AMeV 12Be beam.

Highly charged ECR ion source development at IMP

Highly charged ECR ion source development plays an important role in the heavy ion accelerators advancement at IMP, such as HIRFL upgrade, heavy ion treatment complex HIMM, future heavy ion facility HIAF, and so on. As requested by those projects, many high performance highly charged ECR ion sources with different technologies have been built, or under development. The representative ion sources are superconducting ECR ion sources SECRAL and recently built SECRAL-II, room temperature LECR4 ion source with an innovative evaporative cooling method, permanent magnet ECR ion sources of LAPECR series, and a 45 GHz 4th generation ECR ion source FECR. In this talk, a general review of highly charged ECR ion sources will be presented. The typical performances, operation status, as well as the future developments will be dis-cussed.

Advances of the FRIB project

The Facility for Rare Isotope Beams (FRIB) Project has entered the phase of beam commissioning starting from the room-temperature front end and the superconducting linac segment of first 15 cryomodules. With the newly commissioned helium refrigeration system supplying 4.5[Formula: see text]K liquid helium to the quarter-wave resonators and solenoids, the FRIB accelerator team achieved the sectional key performance parameters as designed ahead of schedule accelerating heavy ion beams above 20[Formula: see text]MeV/u energy. Thus, FRIB accelerator becomes world’s highest-energy heavy ion linear accelerator. We also validated machine protection and personnel protection systems that will be crucial to the next phase of commissioning. FRIB is on track towards a national user facility at the power frontier with a beam power two orders of magnitude higher than operating heavy-ion facilities. This paper summarizes the status of accelerator design, technology development, construction, commissioning as well as path to operations and upgrades.

X-ray investigation on the Superconducting Source for Ions (SuSI)

Heavy ion facilities such as the National Superconducting Cyclotron Laboratory (NSCL) often use ECR Ion Sources (ECRIS) for the production of highly charged ions to increase the efficiency of accelerating structures. Axial bremsstrahlung emission was studied on the Superconducting Source for Ions (SuSI) at the NSCL for 18 GHz and 13 GHz operation with oxygen. The hot electron temperatures were estimated from the bremsstrahlung high energy tail and seem to depend only on magnetic minimum in the same way as was found on VENUS [1], even in the case where 18 GHz and 13 GHz frequencies were compared for similarly sized ECR zones. Additionally, the time independent x-ray power increased at a significantly larger rate when operating the source in known regions of instability such as where the magnetic minimum approaches the ECR zone [2]. The results are discussed in the context of electron losses due to magnetic confinement.

The Future of High-Energy Heavy-Ion Facilities

The plans within the next decade of the high-energy heavy-ion facilities RHIC at BNL and LHC at CERN are reviewed in detail, focusing on the physics programme for sNN≥200GeV. The expected data samples are presented, together with a discussion of the physics programme and reach. Selected performance studies are presented. An outlook is given on the plans with these and new facilities beyond 2030.

Splitting of fragmentation peaks of light ions in 56Fe + 9Be collisions at 0.23 GeV/nucleon

The FRAGM experiment at the ITEP-TWA heavy ion facility has a unique opportunity of measuring the momentum distributions of nuclear fragments. We present the results of 56Fe fragmentation into light ions on 9Be target at 0.23 GeV/nucleon. The momentum spectra of projectile like fragments were measured with a high resolution beam line spectrometer. In contrast to the carbon fragmentation, where the momentum spectra have Gaussian-like shapes, in the emission of the light fragments the shapes have a double-humped structure. This splitting is most pronounced in proton spectra. The possibility of describing this effect by asymmetric fission and multifragmentation is discussed. A comparison is made with the results of the FRS measurements at GSI. The obtained experimental data are in a reasonable agreement with the predictions of several transport codes such as BC, INCL and LAQGSM.