Intense Proton Research Articles

The PSI meson target facility and its upgrade IMPACT-HIMB

The high intensity proton accelerator complex (HIPA) at the Paul Scherrer Institute (PSI) delivers a 590 MeV CW proton beam with currents up to 2.4 mA (1.4 MW). Besides two spallation targets for thermal/cold neutrons (SINQ) and for ultracold neutrons (UCN), the beam feeds two meson production targets Target M and Target E. The targets consist of graphite wheels of effective thickness 5 mm (M) and 40/60 mm (E). The target stations M and E are of quite different design; however, both of them rotate at 1 Hz to dissipate the heat (20 kW/mA for the 40 mm target E) efficiently. Recent progress was made by a new type of bearings and a new target geometry able to increase the rate of surface muons by up to 50 %. This is also foreseen for the upgrade of the target station M within the High Intensity Muon Beam (HIMB) initiative aiming to increase the surface muons available for experiment by two orders of magnitude. HIMB is part of IMPACT (Isotope and Muon Production with Advanced Cyclotron and Target Technology), an application for the Swiss Roadmap of Research Infrastructure.

Design studies on a high-power wide-band RF combiner for consolidation of the driver amplifier of the J-PARC RCS

A power upgrade of the existing 8-kW solid-state driver amplifier is required for the acceleration of high intensity proton beams on the J-PARC 3-GeV Rapid Cycling Synchrotron. The development of a 25-kW amplifier with gallium nitride (GaN) HEMTs, based on 6.4-kW modules is ongoing. The combiner is a key component to achieve such a high output power over the wide bandwidth required for multi-harmonic RF operation. This paper presents the preliminary design of the combiner. The circuit simulation setup and results, including the realistic magnetic core characteristics and frequency response of the cable, are reported.

Cross-Section Measurements of the 11B(p,α)2α Reaction near the First Resonant Energy

In preparation for an experiment with a laser-generated intense proton beam at the Laser Fusion Research Center at Mianyang to investigate the 11B(p,α)2α reaction, we performed a measurement at very low proton energy between 140 keV and 172 keV using the high-voltage platform at the Institute of Modern Physics, Lanzhou. The aim of the experiment was to test the ability to use CR-39 track detectors for cross-section measurements and to remeasure the cross-section of this reaction close to the first resonance using the thick target approach. We obtained the cross-section σ = 45.6 ± 12.5 mb near 156 keV. Our result confirms the feasibility of CR-39 type track detector for nuclear reaction measurement also in low-energy regions.

Status of the COMET experiment

The COMET (COherent Muon to Electron Transition) experiment, currently being built in Tokai, Japan, will search for the coherent neutrinoless transition of muons to electrons in the coulomb field of atomic nuclei. The process is highly suppressed in the Standard Model and therefore provides a promising channel to probe new physics. The experiment will be carried out in a staged approach. Phase-I of COMET aims to search for the process with a single event sensitivity of 𝒪(10−15). Additionally, precise measurements of muon beam dynamics and detector prototyping for Phase-II will be conducted. Utilizing a much higher intensity proton beam, a more complex and longer muon/electron transport system, and gained experience from Phase-I, an improvement of at least four orders of magnitude over the current best branching ratio limit up to 𝒪(10−17) is envisioned for Phase-II. This article will give a status report for Phase-I of COMET.

A beam position monitor for electron bunch detection in the presence of a more intense proton bunch for the AWAKE Experiment

The Advanced Proton Driven Plasma Wakefield Experiment (AWAKE) at CERN uses 6 cm long proton bunches extracted from the Super Proton Synchrotron (SPS) at 400 GeV beam energy to drive high gradient plasma wakefields for the acceleration of electron bunches to 2 GeV within a 10 m length. Knowledge and control of the position of both copropagating beams is crucial for the operation of the experiment. Whilst the current electron beam position monitoring system at AWAKE can be used in the absence of the proton beam, the proton bunch signal dominates when both particle bunches are present simultaneously. A new technique based on the generation of Cherenkov diffraction radiation (ChDR) in a dielectric material placed in close proximity to the particle beam has been designed to exploit the large bunch length difference of the particle beams at AWAKE, 200 ps for protons versus a few ps for electrons, such that the electron signal dominates. Hence, this technique would allow for the position measurement of a short electron bunch in the presence of a more intense but longer proton bunch. The design considerations, numerical analysis and plans for tests at the CERN Linear Electron Accelerator for Research (CLEAR) facility are presented.

Does Uranus' Asymmetric Magnetic Field Produce a Relatively Weak Proton Radiation Belt?

AbstractSince the Voyager 2 flyby in 1986 the radiation belts of Uranus have presented a problem for physicists. The observations indicate the electron radiation belt is far more intense than the proton radiation belt, and while the electron intensities are close to the upper theoretical limit, proton intensities are well below. Here we propose the relatively weak proton radiation belt could be due to Uranus' asymmetric magnetic field. We model test particle motion through the field to show that perturbations arising from asymmetry are greater the larger the particle gyroradius, predominantly affecting 100‐keV protons. For these particles, more rapid changes in maximum distance from the planet during a bounce motion promote trajectory evolution into regions where they could be lost through impact with the rings, impact with the atmosphere, or to the distant magnetosphere and solar wind. We suggest this could explain a relatively weak proton radiation belt at Uranus.

Investigation of resistive magnetic field generation by intense proton beams in dense plasmas

Current and future applications of intense proton sources abound, including radiography, cancer therapy, warm dense matter generation, and inertial confinement fusion. With increasingly efficient acceleration and focusing mechanisms, proton current densities may soon approach and exceed 1010 A/cm2, e.g., via intense laser drivers. Simulations have previously shown that in this current density regime, beam-induced field generation plays a significant role in beam transport through dense plasmas. Here, we present a theoretical model for the generation of resistive magnetic fields by intense proton beam transport through solid density plasmas. The theoretical evolution of the magnetic field profile is calculated using an analytic model for aluminum resistivity, heat capacity, and stopping power, applicable from cold matter to hot plasma. The effects of various beam and material parameters on the field are investigated and explained for both monoenergetic and Maxwellian proton beams. For a proton beam with Maxwellian temperature 5 MeV and total energy 10 J, the model calculates resistive magnetic fields up to 150 T in aluminum. The calculated field profiles from several beam cases are compared with 2D hybrid particle-in-cell simulations, with good agreement found in magnitude and time scale.

Development of the novel and superior adaptive beam-loading compensation system calculated in the frequency domain for the J-PARC Linac

The Japan Proton Accelerator Research Complex (J-PARC) is one of the highest intensity proton accelerator facilities in the world. Its accelerator consists of a 400-MeV linac (LINAC), a 3-GeV rapid-cycling synchrotron (RCS), and a 30-GeV main ring (MR) and its beam is provided for wide-ranging applications. The peak current of the beam at LINAC had been increased from 30 mA to the design value of 50 mA in 2018. Therefore, the performance of the beam-loading compensation implementing in the low-level radio frequency (LLRF) system has been more important to satisfy the stability of the accelerating gradient. Although the iterative learning control (ILC) scheme with adaptive ability was demonstrated, the practical use of ILC was not convenient for large accelerators such as the J-PARC LINAC with forty-nine RF stations. Therefore, we developed at novel and superior adaptive beam-loading compensation system that was calculated in the frequency domain. Compared to the scheme of the previous ILC, the newly developed system is useful because it does not require parameter adjustment using the beam. In the experimental results utilizing this system, the optimum tables of FF_BEAM were able to be obtained as a smaller number of iterations. The peak-to-peak stability of amplitude was achieved to ± 0.23% and the peak-to-peak stability of phase was improved to ± 0.036°. In addition, errors such as white noise did not accumulate for the table of FF_BEAM and this system solved the problem of the divergence when the number of iterations was increased. This implementation of the adaptive beam-loading compensation system calculated in the frequency domain will potentially contribute to the improvement of the J-PARC LINAC LLRF, and this system may lead to a stable user operation. This system is so simple in principle and effective that it could be applied to other linear accelerators with the pulsed beam.

Patient Reported Quality of Life after Moderately Hypofractionated Proton Beam Therapy or Intensity Modulated Radiation Therapy for Prostate Cancer

<h3>Purpose/Objective(s)</h3> We aim to quantify and compare changes in patient reported quality of life (PRQOL) after moderately hypofractionated (MHF) Proton Beam Therapy (PBT) or Intensity Modulated Radiation Therapy (IMRT) for prostate cancer (PC). <h3>Materials/Methods</h3> This multi-institutional analysis included patients with NCCN low or intermediate risk PC treated at 4 tertiary cancer centers with MHF PBT or IMRT with prospective PRQOL collection. Patients completed International Prostate Symptom Score (IPSS) and Expanded Prostate Cancer Index Composite for Clinical Practice (EPIC) pre-treatment and at 3-to-6-month intervals starting at the end of treatment. EPIC is a questionnaire measuring health related quality of life (HRQOL) domains of genitourinary (GU), gastrointestinal (GI), sexual, and hormonal function. Questions are scored from 0 (no problem) to 4 (big problem). EPIC score of 3 or more was considered a meaningful QOL decrement. IPSS measures GU HRQOL; each question is measured from a score of 0 to 5 with a maximum score of 35. Baseline characteristics were compared with Chi squared and t test for IPSS. Models were limited to long term data, at 12 and 36 months. Generalized linear regression models testing effects of time, treatment, and their interaction were fit via Generalized Estimating Equations, controlling for age, race, and NCCN risk group. <h3>Results</h3> 287 IMRT and 485 PBT patients were included. Intermediate NCCN risk group (81.2 vs. 68.2%; p < 0.001), median age at diagnosis (70 vs 66.9 years; p < 0.001) were higher in the IMRT group. Mean IPSS was slightly worse at baseline in the PBT arm (+0.22; CI, -1.54 – 1.10; p=0.74) and slightly better at 3 years (-0.09; CI, -1.48 – 1.65; p=0.91). On Poisson regression controlling for age, race, and NCCN risk group, PBT IPSS trended worse at 12 months (OR, 1.19; CI, 0.98 - 1.44; p=0.077) without any difference at 36 months (OR, 1.08; CI, 0.80 - 1.26; p=0.94). Similarly, EPIC questionnaire for overall GI function trended worse with PBT at 12 months (CI, 0.83 - 16.27; p=0.085) without difference at 36 months (CI, 0.49 - 12.27, p=0.27). 4.9% and 4.8% patients in the PBT and IMRT arms, respectively, rated their overall GI function at 12 months as a severe problem. Among PBT and IMRT patients combined, severe GU concerns were unlikely at 12 months (GU frequency: 17.5; GU pain: 3.6; stream problem: 11.2%). <h3>Conclusion</h3> PRQOL showed a non-significant trend toward worse 1-year overall GI function and IPSS for PBT; this effect was not present at 3 years. In this multi-institutional, prospective study of PC, long-term GU and GI function was not significantly different between PBT or IMRT arms.

Modeling Variable Proton Relative Biological Effectiveness (RBE) Using Voxel-Level Image Density Change for Non-Small Cell Lung Cancer (NSCLC) Patients Treated with Passive Scattering Proton Therapy (PSPT) or Intensity Modulated Photon Therapy (IMRT)

<h3>Purpose/Objective(s)</h3> To test the hypothesis that radiation damage measured via lung image density change is a function of variable RBE for protons with a coefficient of determination (R²) greater than 0.8. <h3>Materials/Methods</h3> Data from 61 NSCLC patients previously treated on a prospective clinical trial with PSPT (N = 24) or IMRT (N = 37) to 74 Gy(RBE) (proton RBE of 1.1) were acquired. Patients with noticeable atelectasis or pleural effusion were excluded. For each patient, a ∼5-month post-treatment PETCT was obtained to assess response and was deformed to the planning exhale phase of the 4DCT (exCT) via a biomechanical model-based image registration algorithm. Subsequently, voxel-level image density change (IDC) within the normal ipsilateral lung was obtained by subtracting the exCT from the deformed PETCT, as a signal of biological damage. IMRT dose (D_x) was recalculated on the exCT using a commercial treatment planning system while the PSPT dose (D_p) and dose-averaged linear energy transfer (LET_d) were recalculated on the exCT using a commissioned track-repeating Monte-Carlo system. The fitted variable RBE models included a linear model (RBE = 1 + λ•LET_d) and a linear-quadratic (LQ) model (RBE = 1/(2D_p)•{√[(α/β)² + 4D_p(α/β)(p₀+(p₁•LET_d)/(α/β) + 4D_p²(p₂ + p₃•√(α/β)•LET_d)] - α/β}) with α/β = 3 Gy for lung tissue. <b>RBE was modeled against the ratio between D_x and D_p at given IDC levels.</b> We adapted Lyman-Kutcher-Burman normal tissue complication probability (NTCP) model to fit the dose-IDC relationship for each cohort by averaging the dose and IDC of voxels in 5-Gy dose intervals (adaptations: n = 1, effective dose = voxel dose, and complication probability = IDC normalized against global min and max IDC). LET_d corresponding to each D_p was approximated by averaging the LET_d of voxels that received D_p with a margin of 0.001Gy. All NTCP and RBE models were fitted using non-linear least squares with the Python SciPy package. <h3>Results</h3> For NTCP fitting, min and max IDC were 2.7 HU and 136.3 HU, respectively, and TD₅₀ and m were fitted to be 31.5 Gy and 0.51 for PSPT (R² = 0.99) and 44.4 Gy and 0.40 for IMRT (R² = 0.98). The table shows the IDC levels, the corresponding LET_d (SD), and the fitted D_x and D_p. The linear model resulted in λ = 0.154 µm/keV (R² = 0.27), and the LQ model resulted in p₀ = -0.72, p₁ = 10.02, p₂ = 1.51, and p₃ = -0.08 (R² = 0.999). <h3>Conclusion</h3> The study demonstrates that voxel-level radiation damage and image changes for proton therapy are functions of dose and LET and, thus, variable RBE.

Probing the losses for a high power beam

The High Intensity Proton Accelerator (HIPA) cyclotron at the Paul Scherrer Institut (PSI) delivers 590 MeV CW proton beam with a maximum power of 1.42 MW. After extraction, the beam is transferred in a 120 m long channel towards two target stations (TgM and TgE) for surface muon production before depositing its remaining power at the spallation target SINQ for neutron production. As part of the High Intensity Muon Beamline (HIMB) feasibility study, the first of these targets will be replaced with a thicker one thereby increasing the rate of surface muon production. However, a key challenge for HIMB is to maintain the proton beam losses to the lowest possible levels which requires improving our understanding of the distributed losses along the MW-class beamline. To this end, a new approach was developed where the aim is to relate the experimental values of the temperature, beam profile measurements as well as beam current measurements to the combined power deposition calculations and primary beam losses using Monte Carlo simulation tools.

Characterization of Stray Radiation Produced by a Proton Beam in an Anthropomorphic Phantom with Dental Implants Using a Pixel Detector

<h3>Purpose/Objective(s)</h3> We investigated the scattered radiation produced by a collimated proton beam in the case of head and neck cancer using an anthropomorphic head phantom with human-like anatomy, with two dental implants inserted. Using high-resolution semiconductor pixel detectors, we measured and analyzed the backscatter radiation with particle identification resolving power. This research is focused on giving quantitative information about the radiation field components. <h3>Materials/Methods</h3> A treatment plan was designed on a standard X-ray CT which contained the implants at the center of the tumor. Two irradiations of an anthropomorphic head phantom were performed with clinical proton beams: one without metallic implants (plastic inserts) and one with dental implants. Two titanium cylindrical inserts of 1 cm length and 0.33 cm diameter were placed in the phantom's upper jaw like the molar's replacements. The planning target volume (PTV) is shaped so that the dental inserts are centered in the target volume. A scattered fixed proton beam with a nominal energy of 170 MeV was delivered to the phantom using collimators and boluses designed to shape and stop the beam according to the treatment plan. Scattered primary and secondary radiation was detected with hybrid semiconductor pixel detectors, placed at 4 cm behind the PTV. Detailed description of the mixed-radiation field was performed with spectral (energy loss) and tracking (direction) sensitivity. <h3>Results</h3> Measurements included a low intensity proton beam to assess the particle tracking response and identification resolving power in both situations (with and without implants). In this manner, the components of the radiation field were observed and analyzed. Based on their characteristic directional-sensitive spectral-track signal in the detector, both primary and secondary protons can be distinguished from light charged particles. This was done by analyzing single particle pixelated clusters morphology, spectral and directional sensitive parameters. Directional fluxes and linear energy transfer (LET) spectra of charged particle groups provide information about the scattered radiation field. <h3>Conclusion</h3> We present novel information about dental metallic implants' influences in a proton-based treatment. Preliminary results show differences in the LET distributions of the scattered radiation when the implants are in place, respectively, when they are missing. Further analyses will be done to provide a detailed dissemination of contribution for every type of particle.

Chlororespiration as a Protective Stress-inducible Electron Transport Pathway in Chloroplasts

Chlororespiration is the uptake of oxygen into the respiratory electron transport chain (ETC) localized in the thylakoid membranes of chloroplasts. The chlororespiratory ETC interacts with photosynthetic electron transport and participates in the non-photochemical reduction/oxidation of the plastoquinone pool (PQP) accompanied by O2 consumption. The two key thylakoid enzymes in chlororespiration are the plastid-encoded NAD(P)H dehydrogenase complex (NDH) and the nucleus-encoded terminal plastoquinol oxidase (PTOX). The contribution of chlororespiratory electron flux to the total electron flow in non-stressed plants is considered insignificant. In contrast, under abiotic stresses, chlororespiration appears to be triggered, at least in some photosynthetic organisms, acting as a protective alternative electron transport pathway. There is evidence of NDH complex and PTOX increasing their activity and/or abundance when plants experience high light, drought, heat, or low-temperature stresses. Alternative electron transfer to oxygen via PTOX protects PQP from over-reduction under stress conditions. For instance, it was shown that PTOX-dependent electron drainage accounted for up to 30% of total PSII electron flow in salt-stressed plants. PTOX is not bound to the thylakoid membrane in dark-adapted leaves but is associated with it at intense illumination and high transmembrane proton gradient (ΔpH) or membrane potential (Δψ). It was also shown that PTOX is capable of lateral translocation from stromal lamellae to granal thylakoid stacks under salt stress. Such changes in PTOX localization increase the accessibility of the substrate (plastoquinol) and the turnover rate of the enzyme. The available data allow considering PTOX as a possible target for manipulation to increase stress tolerance in sensitive plants.

Plasma characterization in CW and pulsed mode and its effect on beam current in 2.45 GHz ECR Ion source

Electron Cyclotron Resonance Ion Source (ECRIS) is used as a front end for Low Energy High Intensity Proton Accelerator (LEHIPA) at BARC. A 50 keV ECRIS is designed and developed for the proton ion beam for this accelerator. The key requirements of the ion source are beam current ∼ 10 – 15 mA and beam emittance ∼ 0.2 π mm-mrad. In the commissioning phase of LEHIPA, the ion source is operated in pulsed mode to mitigate the effect of thermal and radiation load. Measurements have been carried out to understand the behavior of pulsed plasma and its effect on ion beam. An Automated Langmuir Probe (ALP) and its associated circuit are designed and developed for this purpose. The ALP circuit consists of a voltage sweep generator, current sense circuit, and voltage sense circuit. The effect of microwave power and pulsed plasma duration on the plasma and the ion beam parameters have been studied. The plasma parameters are correlated with the beam parameters.

A large area efficient trigger scintillator with SiPM read out

A large area plastic scintillator detector system with SiPM read out has been prepared in order to improve the trigger selectivity for reaction studies induced by an intense proton beam with a beam momentum of several GeV/c. The system consists of six trapezoidal modules, each with three plastic scintillator elements that are each equipped with 12 SiPMs. The detection of a charged particle is based on registering coincident signals in several SiPMs. By requiring a signal on at least two of the SiPMs, the noise rate is negligible and a detection efficiency close to 100% is achieved.

RONC-03. Secondary Neoplasms in Children with Central Nervous System (CNS) Tumors Following Radiotherapy in the Modern Era

PURPOSE: To assess reduction of secondary radiation-induced neoplasms over the past two decades, focusing on children with CNS tumors who received intensity modulated radiotherapy (IMRT) or proton therapy (PT). METHODS: A total of 1044 children received radiotherapy for a primary CNS tumor at 2 institutions between 1999 and 2020, including 99 treated with IMRT and 945 treated with PT. Median age was 8.7 years old. Median follow-up was 6.0 years and included 83 and 510 patients with >5 years follow-up in the IMRT and proton cohorts, respectively. Cumulative incidence method provided estimates of secondary neoplasms encompassing benign and malignant solid tumors as well as leukemia. Multiple variables were assessed using proportional hazard regression for competing risks. RESULTS: Ten-year overall survival was 87.4%. Patients treated with IMRT were significantly older, with a median age of 10.4 vs 8.4 years old (p <0.001), but were more likely to receive craniospinal irradiation (31.3% vs 14.2%, p <0.001) or alkylating chemotherapy (50.5% vs 29.7%, p <0.001). The 5- and 10-year cumulative incidence of second neoplasm was 0.7% and 2.3%, respectively. On multivariate analysis, age <5 (4.9% vs 0.7% at 10 years) and tumor predisposition syndrome (34.3% vs 1.5% at 10 years) were significantly associated with a second neoplasm (p < 0.01 for each). On both univariate and multivariate analyses, PT was not associated with a lower incidence of second neoplasm. Following IMRT, 1/2 second solid tumors occurred outside the target volume, compared to 2/11 after PT. CONCLUSION: Following modern radiotherapy, approximately 2% of children with a CNS tumor will develop a second neoplasm within 10 years of treatment. Compared to IMRT, PT was not associated with an overall reduction in second neoplasms. More events and follow-up beyond 10 years are needed to determine if proton therapy reduces the incidence of second solid tumors occurring specifically in the low dose region.

Transport of an intense proton beam from a cone-structured target through plastic foam with unique proton source modeling.

Laser-accelerated proton beams are applicable to several research areas within high-energy density science, including warm dense matter generation, proton radiography, and inertial confinement fusion, which all involve transport of the beam through matter. We report on experimental measurements of intense proton beam transport through plastic foam blocks. The intense proton beam was accelerated by the 10ps,700J OMEGA EP laser irradiating a curved foil target, and focused by an attached hollow cone. The protons then entered the foam block of density 0.38g/cm^{3} and thickness 0.55 or 1.00mm. At the rear of the foam block, a Cu layer revealed the cross sectionof the intense beam via proton- and hot electron-induced Cu-K_{α} emission. Images of x-ray emission show a bright spot on the rear Cu film indicative of a forward-directed beam without major breakup. 2D fluid-PIC simulations of the transport were conducted using a unique multi-injection source model incorporating energy-dependent beam divergence. Along with postprocessed calculations of the Cu-K_{α} emission profile, simulations showed that protons retain their ballistic transport through the foam and are able to heat the foam up to several keV in temperature. The total experimental emission profile for the 1.0mm foam agrees qualitatively with the simulated profile, suggesting that the protons indeed retain their beamlike qualities.

Development of ECR ion source with high-temperature superconducting REBCO coils

A new High-Temperature Superconducting ECR (HTS-ECR) ion source is under development in Research Center for Nuclear Physics (RCNP), Osaka University. This ion source will be used for production of high intensity proton, deuteron and He ion beams. The HTS-ECR magnets are composed of three solenoid coils and a set of sextupole coils made of REBCO tapes, a high-temperature superconductor. The HTS-ECR ion source is designed to operate at frequency of 2.45 GHz and 10 GHz. Performance test of the HTS coils had been carried out at 31 K and 77 K. This HTS coil technology will be applied to development of a meter-size HTS coil system of a high intensity compact AVF cyclotron. This paper introduces the basic design of the HTS-ECR ion source. The performance test results showed that REBCO solenoids remain superconducting state with a current up to 400 A. Simulation results of the magnetic field and electromagnetic field distributions in a plasma chamber fulfilled the requirements of electron cyclotron resonance conditions at 2.45 GHz and 10 GHz. Simulation result of mirror ratios and electromagnetic field amplitudes are also presented in this paper.

Excitation functions of natNi(p, x) reactions in the energy range of 75–100 MeV

Stacked-foil activation technique and high-resolution gamma spectrometry were used to investigate new excitation functions of proton-induced nuclear reactions on natNi targets in the energy range of 75–100 MeV. The stack foils were irradiated with 100 MeV protons at the separated-sector cyclotron of the Institute of Modern Physics, Chinese Academy of Sciences, China. The proton intensity for each nickel foil was determined using the natNi(p, x)57Ni monitor reaction. The cross-sections of the natNi(p, x)56Ni, 55,57,58Co, and 54Mn reactions were calculated and compared with the existing literature data presented in the Experimental Nuclear Reaction Data (EXFOR). Furthermore, evaluated nuclear data of the PADF-2007, ENDF/B-VIII.0, and JENDL-4.0/HE libraries as well as theoretical calculations of the TALYS code were used. Overall, our experimental data agree with the majority of the literature data. The results of TALYS code as well as the ENDF/B-VIII.0 and JENDL-4.0/HE libraries could reproduce most of the experimental trend, whereas the results of PADF-2007 library could not do so. The new experimental results provide cross-sections for proton-induced natNi reactions in the energy range of 75–100 MeV and could serve as a technical assistance for radionuclide production and radiation safety practices.

Minimizing emittance growth via low emittance transfer

The longitudinal-transverse coupling is an important source for space-charge-induced emittance growth in high intensity proton and ion linacs. Different from the equipartitioning method which tries to avoid the longitudinal-transverse coupling, a new design approach has been developed to minimize emittance growth via the low emittance transfer enabled by holding the ratio of longitudinal emittance to transverse emittance in the range of 0.9--1.4. Using a high intensity radio-frequency quadrupole accelerator as an example, a comparison between the new approach and the equipartitioning method has been made. Furthermore, input beams with non-nominal beam intensities and emittances have been applied to the designed accelerator. The simulation results show that the design obtained by following the new approach has a large tolerance for the off-design situations.