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Background: Pencil beam scanning (PBS) proton therapy for moving targets is known to be impacted by interplay effects between the scanning beam and organ motion. While respiratory motion in the thoracic region is the major cause for organ motion, interplay effects depend on the delivery characteristics of proton accelerators. Purpose: To evaluate the impact of different types of PBS proton accelerators and spot sizes on interplay effects, mitigations, and plan quality for Stereotactic Body Radiation Therapy (SBRT) treatment of non‐small cell lung cancer (NSCLC). Methods: Twenty NSCLC patients treated with photon SBRT were selected to represent varying tumor volumes and respiratory motion amplitudes (median: 0.6 cm with abdominal compression) for this retrospective study. For each patient, plans were created using: (1) cyclotron‐generated proton beams (CPB) with spot sizes of σ = 2.7–7.0 mm; (2) linear accelerator proton beams (LPB) (σ = 2.9–5.5 mm); and (3) linear accelerator proton minibeams (LPMB) (σ = 0.9–3.9 mm). The energy switching time is one second for CPB, and 0.005 s for LPMB and LPB. Plans were robustly optimized on the gross tumor volume (GTV) using each individual phase of four‐dimensional computed tomography (4DCT) scans. Initially, single‐field optimization (SFO) plans were evaluated; if the plan quality did not meet the dosimetric requirement, multi‐field optimization (MFO) was used. MFO plans were created for all patients for comparisons. For each patient, all plans were normalized to have the same dose received by 99% of the GTV. Interplay effects were evaluated by computing the dose on 10 breathing phases, based on the spot distribution. Volumetric repainting (VR) was performed 2–6 times for each plan. We compared volume receiving 100% of the prescribed dose (V100%RX) of the GTV, and normal lung V20Gy. Results: Twelve of 20 plans can be optimized sufficiently with SFO. SFO plans were less sensitive to the interplay effect compared to MFO plans in terms of target coverage for both LPB and LPMB. The following comparisons showed results utilizing the MFO technique. In the interplay evaluation without repainting, the mean V100%RX of the GTV were 99.42 ± 0.6%, 97.52 ± 3.9%, and 94.49 ± 7.3% for CPB, LPB, and LPMB plans, respectively. Following VR (2 × for CPB; 3 × for LPB; 5 × for LPMB), V100%RX of the GTV were improved (on average) by 0.13%, 1.84%, and 4.63%, respectively, achieving the acceptance criteria of V100%RX > 95%. Because of fast energy switch in linear accelerator proton machines, the delivery time for VR plans was the lowest for LPB plans, while delivery time for LPMB was on average 1 min longer than CPB plans. The advantage of small spot machines was better sparing in normal lung V20Gy, even when VR was applied. Conclusion: In the absence of repainting, proton machines with large spot sizes generated more robust plans against interplay effects. The number of VR increased with decreasing spot sizes to achieve the acceptance criteria. VR improved the plan robustness against interplay effects for modalities with small spot sizes and fast energy changes, preserving the low dose sparing aspect of the LPMB, even when motion is included. [ABSTRACT FROM AUTHOR]

The potential of prompt gamma analysis based on inelastic scattering of 2.5 MeV neutrons for a rapid characterization of NdFeB permanent magnets is investigated by means of numerical simulations using an HPGe detector and a CZT detector-array. The results show that rapid assay of a 42 g magnet can be achieved in some minutes when the neutron flux at sample position is about 1.6 × 109 cm−2 s−1 and the detector count rate limited to 500 kcps. Such a high neutron flux could be delivered by a compact 5 MeV proton accelerator with a thick beryllium target for neutron production through the 9Be(p,xn)9Be. [ABSTRACT FROM AUTHOR]

In the 1960s, the remnants of supernova explosions (SNRs) were indicated as a possible source of galactic cosmic rays through the Diffusive Shock Acceleration (DSA) mechanism. Since then, the observation of gamma-ray emission from relativistic ions in these objects has been one of the main goals of high-energy astrophysics. A few dozen SNRs have been detected at GeV and TeV photon energies in the last two decades. However, these observations have shown a complex phenomenology that is not easy to reduce to the standard paradigm based on DSA acceleration. Although the understanding of these objects has greatly increased, and their nature as efficient electron and proton accelerators has been observed, it remains to be clarified whether these objects are the main contributors to galactic cosmic rays. Here, we review the observations of γ -ray emission from SNRs and the perspectives for the future. [ABSTRACT FROM AUTHOR]

The neutron total and capture cross sections of 181Ta were measured at the Accurate Neutron-Nucleus Research Measurement Instrument of the Materials and Life Science Experimental Facility in the Japan Proton Accelerator Research Complex to improve the accuracy of the current resonance parameters. The total cross section was determined from the transmission measurement in the energy range from 0.2 to 150 eV. The capture cross section was derived from the capture yield using the pulse height weighting technique in the energy range from thermal to 150 eV. The thermal neutron capture cross section was measured as $$21.3 \pm 0.3(stat) \pm 0.6(sys)$$ 21.3 ± 0.3 (stat) ± 0.6 (sys) b. The obtained transmission and capture cross section were simultaneously fitted using the resonance analysis code REFIT, and the resonance parameters for resonances below 150 eV were evaluated. The present resonance parameters were compared to reported measurements. [ABSTRACT FROM AUTHOR]

The Muon Science Establishment (MUSE) at the Japan Proton Accelerator Research Complex (J-PARC) introduced an intense pulse surface muon beam for material science in late 2017. This development at MUSE enables researchers to utilize this highly controlled muon beam to study materials with enhanced accuracy and reliability. Our work aims to investigate proton transmission, surface muon production, contamination on a surface muon beam, and characteristics of the beam at surface muon beamline. Using Monte Carlo simulation programs, GEANT4 and G4beamline, to study interactions between the 3 GeV proton beam and the muon target. The results showed 95.43% proton transmission through the muon target. At the S-line entrance, the surface muon yield is 1.43 × 10 - 7 . The transverse positional distribution and phase space of the surface muon beam were also provided in this study. Our findings present an asymmetry along the horizontal axis and the beam entering the S-line is characterized as divergent, increasing in its transverse size. In summary, the primary proton beam loss at the muon target is 4.57%, which falls within the acceptable range for neutron facility operations that share the proton beam with the muon facility. The characteristics of the surface muon beam will be used for beam dynamic calculation and compared with the result considering the leakage magnetic fields from neighboring beamlines. [ABSTRACT FROM AUTHOR]

Results of calculations of the electrodynamic characteristics of short five-gap accelerating cavities of the IH type are presented. The cavities are designed for a linear accelerator of protons and light ions with a charge-to-mass ratio A/Z ranging from 1 to 3.5. Developed at National Research Nuclear University MEPhI, this accelerator, which is designed as a source of charged particles with a beam energy of 7.5 MeV/nucleon, is intended for basic and applied research. The issues of the complex influence of the geometry of the drift tubes and the geometry of the drift tube support on the magnitude of the field strength on the surface of the resonators, the power losses in the walls of the resonators, and the distribution of the accelerating field on the axis are considered, taking into account the influence of the accuracy of segmenting in simulation. [ABSTRACT FROM AUTHOR]

At the Prometheus medical accelerator with a proton beam energy of 225 MeV, a source of fast and epithermal neutrons is constructed and the neutron dose profiles are measured at the output of the neutron channel using the BDMN-100 detector. A heavy NaI target is used to produce fast neutrons. Together with the research laboratory of the Central Laboratory of AO Avangard, a new protective material against neutrons called wikineutron is developed, with a different percentage of 10B. Based on the developed new protective materials against neutrons, a shadow protection is formed, made in the form of surface contacting cones, forming a channel of fast and epithermal neutrons. Fast neutrons can be used for remote therapy. The developed neutron channel can be used for medical work on the creation of new radiopharmaceuticals containing boron and other highly absorbing elements. It is also possible to use a neutron source from the Prometheus accelerator for the treatment of superficial tumors. The main goal of this study is the formation, based on the developed neutron-absorbing materials, of a neutron channel, which has a simple design and can be used for boron neutron capture therapy (BNCT) and supraepithermal therapy, as well as the creation on the neutron channel of a beam of epithermal neutrons and supraepithermal neutrons to assess the effectiveness of the use of radiopharmaceuticals. The developed neutron-absorbing materials make it possible to create a neutron channel of epithermal neutrons and supraepithermal neutrons for therapy and the development of gold-based radiosensitizers. [ABSTRACT FROM AUTHOR]

Neutron total and capture cross sections of Lanthanum(La)-139 were measured at the Accurate Ne-utron-Nucleus Reaction measurement Instrument (ANNRI) of the Materials and Life Science Experimental Facility (MLF) in the Japan Proton Accelerator Research Complex (J-PARC). The total cross section was deduced from transmission measurement using a Li-glass detector in the energy range from 0.5 to 1500 eV, and the capture cross section was measured by a NaI detector in the energy range from 0.5 to 74 eV. The total cross section was largely different from that in evaluated libraries, such as JENDL-5, in the energy range from 80 to 900 eV. Resonance parameters for four resonances including one negative resonance were obtained using a resonance analysis code, REFIT. The resonance analysis revealed discrepancies in several resonance parameters with the evaluated libraries. Furthermore, the information about the scattering radius was also extracted from the results of the total cross section. The obtained scattering radius was larger than that recorded in the evaluated libraries. [ABSTRACT FROM AUTHOR]

The Low Energy High Intensity Proton Accelerator (LEHIPA) at Bhabha Atomic Research Centre, India, has recently been commissioned to the target energy of 20 MeV by beam acceleration through a 352 MHz radio frequency quadrupole (RFQ) and drift tube linac (DTL). The medium energy beam transport (MEBT) line of LEHIPA matches the 3 MeV beam from RFQ to the DTL using four electromagnetic quadrupoles and a re-buncher cavity. In the beam transport lines of high frequency linacs, TM010 mode single gap buncher cavities are conventionally used, while a double gap re-buncher cavity was chosen for the short length LEHIPA MEBT based on beam dynamics simulations. The 352 MHz double gap re-buncher cavity has been designed in a DTL type geometry with a cell length of βλ. This double gap cavity is found to be more power efficient with a higher shunt impedance and transit time factor than the conventional single gap buncher cavity. Electromagnetic design simulations, fabrication details, low power and high-power RF test results, and beam test results of the re-buncher cavity are presented in this paper. [ABSTRACT FROM AUTHOR]

The recently observed FLASH effect describes the observation of normal tissue protection by ultra-high dose rates (UHDR), or dose delivery in a fraction of a second, at similar tumor-killing efficacy of conventional dose delivery and promises great benefits for radiotherapy patients. Dedicated studies are now necessary to define a robust set of dose application parameters for FLASH radiotherapy and to identify underlying mechanisms. These studies require particle accelerators with variable temporal dose application characteristics for numerous radiation qualities, equipped for preclinical radiobiological research. Here we present the dresden platform, a research hub for ultra-high dose rate radiobiology. By uniting clinical and research accelerators with radiobiology infrastructure and know-how, the dresden platform offers a unique environment for studying the FLASH effect. We introduce its experimental capabilities and demonstrate the platform's suitability for systematic investigation of FLASH by presenting results from a concerted in vivo radiobiology study with zebrafish embryos. The comparative pre-clinical study was conducted across one electron and two proton accelerator facilities, including an advanced laser-driven proton source applied for FLASH-relevant in vivo irradiations for the first time. The data show a protective effect of UHDR irradiation up to 10 5 Gy / s and suggests consistency of the protective effect even at escalated dose rates of 10 9 Gy / s . With the first clinical FLASH studies underway, research facilities like the dresden platform, addressing the open questions surrounding FLASH, are essential to accelerate FLASH's translation into clinical practice. [ABSTRACT FROM AUTHOR]

In this manuscript, production of 201TlCl, one of the radiopharmaceuticals used in the field of nuclear medicine for diagnostic purposes in heart, muscle, thyroid gland imaging, and cancer diagnosis, at Turkish Energy Nuclear and Mineral Research Agency is described. The production process starts with a cyclotron type proton accelerator operated in energy range of 15–30 MeV with beam intensities up to 1200 μA currently available at the facility. The production is detailed along with the main lines in the other steps. In addition to the radiopharmaceutical productions carried out according to international standards at the facility, new projects are planned in the short and long terms. [ABSTRACT FROM AUTHOR]

We study the enhancement of the magnetic dipole induced excitation probability of the hyperfine ground state of Doppler-broadened muonic hydrogen ( p μ - ) by a nanosecond laser pulse in the mid-infrared range with Gaussian temporal shape such that the pulse bandwidth is broader than the Doppler width at 10 K. The enhancement is achieved by shrinking the cross-section of the laser pulse and placing the muonic hydrogen medium in a multipass cavity, while preserving the total irradiated target volume. We numerically solve a set of Maxwell–Schr o ¨ dinger equations to obtain the excitation probability and the total efficiency for various densities of the muonic hydrogen atomic medium and at various positions in the multipass cavity. For the typical range of densities of muonic hydrogen atoms at major proton accelerator facilities such as the J-PARC (density ∼ 10 5 cm - 3 ), the laser propagation effect is insignificant. For such cases, the total efficiency increases by an order of two for 100 reflections with a uniform polarization. If the density exceeds the value of 10 17 cm - 3 as might be in the future advances, the laser propagation effect has to be taken into account, and the total efficiency decreases with the number of reflections giving rise to a pulsed polarization of the beam. Our study can serve as a guideline for the development of a polarized muonic beam for a precise measurement of the ground state hyperfine splitting of muonic hydrogen, or for μ SR experiments. [ABSTRACT FROM AUTHOR]

The strong demand to isotopes for creation of the artificial MeV-energy electron antineutrino sources can be satisfied by Li which is characterized by well defined and hard spectrum. The source can be produced at ( , )-activation of the starting Li isotope. The availability and presence of large mass of Li allow to construct as -source on the base of nuclear reactors (in steady state and dynamical mode of operation) as in tandem scheme of proton accelerators with heavy metal target. The accelerator variant is optimized in efficiency of Li generation and in dimension that is exclusively important for investigation of oscillation in problem of sterile neutrino search in case of eV scale. The analysis of Li creation in the lithium blanket-converter allowed to decrease it outer size down to 70 cm strongly decreasing the escape of neutrons from the source construction. [ABSTRACT FROM AUTHOR]

The article discusses the study of dense compressed matter at the Japan Proton Accelerator Research Complex (J-PARC). It explains that the densest material at the atomic level is osmium, but the density of atomic nuclei is much higher. The article highlights the importance of investigating the properties and phase structures of ultradense materials, which are believed to exist inside neutron stars. The J-PARC is planning to upgrade its facilities to produce high-density matter comparable to the internal density of neutron stars. The article also mentions the study of quark and hadron phase structures, as well as the exploration of color superconducting phases. The J-PARC is described as an experimental facility with multiple accelerators and experimental facilities for various research purposes. The article concludes by stating that experiments involving heavy-ion beams will be conducted at the J-PARC to study the phase structure of strong interactions in the ultrahigh-density regime. [Extracted from the article]

Laser-driven proton accelerators are relevant candidates for many applications such as material science or medicine. Today, there are multi-hundred-TW table-top laser systems that can generate relativistic peak intensities > 1 0 18 W/c m 2 and routinely reach proton energies in the MeV range. However, for most desired applications, there is still a need to optimize the quality and stability of the laser-generated proton beam. In this work, we developed a 0.625 Hz high repetition-rate setup in which a laser with 2.5% RMS energy stability is irradiating a solid target with an intensity of 1 0 19 to 1 0 20 W/c m 2 to explore proton energy and yield variations, both with high shot statistics (up to about 400 laser shots) and using different interaction targets. Investigating the above-mentioned parameters is important for applications that rely on specific parts of the proton spectrum or a high ion flux produced over quick multi-shot irradiation. We demonstrate that the use of a stable "multi-shot mode" allows improving applications, e.g., in the detection of trace elements using laser-driven particle-induced x-ray emission. [ABSTRACT FROM AUTHOR]

Objective. Laser plasma-based accelerators (LPAs) of protons can contribute to research of ultra-high dose rate radiobiology as they provide pulse dose rates unprecedented at medical proton sources. Yet, LPAs pose challenges regarding precise and accurate dosimetry due to the high pulse dose rates, but also due to the sources' lower spectral stability and pulsed operation mode. For in vivo models, further challenges arise from the necessary small field dosimetry for volumetric dose distributions. For these novel source parameters and intended applications, a dosimetric standard needs to be established. Approach. In this work, we present a dosimetry and beam monitoring framework for in vivo irradiations of small target volumes with LPA protons, solving aforementioned challenges. The volumetric dose distribution in a sample (mean dose value and lateral/depth dose inhomogeneity) is provided by combining two independent dose measurements using radiochromic films (dose rate-independent) and ionization chambers (dose rate-dependent), respectively. The unique feature of the dosimetric setup is beam monitoring with a transmission time-of-flight spectrometer to quantify spectral fluctuations of the irradiating proton pulses. The resulting changes in the depth dose profile during irradiation of an in vivo sample are hence accessible and enable pulse-resolved depth dose correction for each dose measurement. Main results. A first successful small animal pilot study using an LPA proton source serves as a testcase for the presented dosimetry approach and proves its performance in a realistic setting. Significance. With several facilities worldwide either setting up or already using LPA infrastructure for radiobiological studies with protons, the importance of LPA-adapted dosimetric frameworks as presented in this work is clearly underlined. [ABSTRACT FROM AUTHOR]

The laboratory experiment was conducted at Joint Institute for Nuclear Research with a prototype of planetary gamma-ray spectrometer (GRS) based on a High Purity Germanium (HPGe) detector and a proton detector (PD) configured with the GRS in the coincidence mode. The instrument set-up allows to detect gamma rays produced in the target irradiated by protons using integrated gamma-ray spectra (all detected gamma rays) as well as tagged gamma-ray spectra that select only photons synchronized with the proton detection. The latter option improves signal-to-noise ratio by selecting prompt photons produced in the irradiated target. The main objective was to conduct experiment with an irradiation of 11 samples of Rare Earth Elements (REEs) with high energy protons (170 MeV) to find a set of uniquely characterized gamma-ray lines that confidently indicate the presence of the given REE. These measurements are acquired to understand the conditions of a hypothetical space experiment on the lunar surface aimed for the reconnaissance of lunar resources. In this experiment, ambient gamma radiation is produced by charged particles of Galactic Cosmic Rays (GCRs). 45 significant gamma-ray lines were found for 11 tested samples of REEs in total. This list includes 7 gamma-ray lines which have already been identified in the existing catalog of characteristic gamma-ray lines produced in the inelastic scattering reactions. 18 gamma-ray lines are unique and they were detected for an individual REE only. Other 27 detected gamma-ray lines are associated with several REEs and therefore were combined into 10 joint groups. Some groups are rather large and consists of 4 REEs. The proposed method of spectrometry with the options of time- integrated and tagged spectra allowed to determine the fraction of the gamma-ray lines, which occurs promptly at moment of proton-nuclei interaction. For some gamma-ray lines such a fraction is rather large and approaching 50%, and for some other gamma-ray lines it could be as small as 10–15%. The obtained experimental results were used to predict the expected intensities of the REEs gamma-ray lines in a future gamma-ray spectrometric experiment on the lunar surface. In particular, for a hypothetical lunar ore field it is estimated that a gamma-ray spectrometer with 10 times larger total effective area, than one used for the experimental set-up, may detect Cerium gamma-ray line at 553 keV after 1.6 h of signal accumulations. • Gamma-ray spectrometry of Rare Earth Elements (REE) on the Moon surface. • Laboratory measurements of REE with prototype of Cosmic Gamma-Ray Spectrometer with HPGe detector. • Reference data for REE nuclear lines from the experiment at proton accelerator. • Detectability of REE nuclear lines on the lunar surface. [ABSTRACT FROM AUTHOR]

Gas ionization chamber has the advantage of accurate and reliable measurement data, which is widely used in beam current monitoring of proton and heavy ion beam therapy systems. According to the characteristics of the proton beam signal of the laser accelerator, because of its ultra-high peak current intensity, the peak current intensity of the beam generated by the traditional accelerator is much higher than that of the traditional accelerator. The gas ionization chamber cannot measure the proton beam with this characteristic, and the incident laser proton beam is likely to cause signal saturation and distortion in the gas ionization chamber. Therefore, it is necessary to improve the physical design of the gas ionization chamber and the supporting electronic system to improve the detection technology of the gas ionization chamber dedicated to the ion beam generated by the laser acceleration. In this paper, the physical design of the gas ionization chamber is optimized to avoid signal saturation in the gas ionization chamber while measuring the laser proton beam signal. With the method of modeling and simulation analysis of the gas ionization chamber based on the Garfield++, the optimal value is given in three aspects: the type selection of the gas medium, the gas pressure setting and the setting of the voltage of the gas ionization chamber in order to optimize the measurement signal saturation phenomenon caused by the large transient beam current intensity, and bring theoretical basis and guiding significance to the actual experimental operation. The research concludes that when helium is selected as the gas medium of the gas ionization chamber, the signal saturation can be effectively reduced; when the integration time of the electronic system of the gas ionization chamber is 500 ns, and the current measurement range is ±16 μA in actual, the optimized gas pressure should be set lower than 540 Torr and the voltage value lower than 300 V to match the electronic measuring range of the gas ionization chamber while detecting the current signal; when the signal detected is the integrated charge, the voltage setting of the gas ionization chamber has nearly nothing to do with the signal collected, but to adjust the gas pressure in the gas ionization chamber to optimize the final data. [ABSTRACT FROM AUTHOR]

We developed a mistake-proofing technique (Poka-Yoke) capable of dealing with the virtual source position delivered by different carbon ion energies for scanning-passive scatter beam in carbon ion therapy. Despite a lot of methods that have been proposed for the determination of virtual source position for electron beam therapy in a linear accelerator and proton beams, none for heavy charged particles-like carbon ions have been investigated. The method can be also used for electron and the proton beams. [ABSTRACT FROM AUTHOR]

Background: Recent proposals of high dose rate plans in protontherapy as well as very short proton bunches may pose problems to current beam monitor systems. There is an increasing demand for real‐time proton beam monitoring with high temporal resolution, extended dynamic range and radiation hardness. Plastic scintillators coupled to optical fiber sensors have great potential in this context to become a practical solution towards clinical implementation. Purpose: In this work, we evaluate the capabilities of a very compact fast plastic scintillator with an optical fiber readout by a SiPM and electronics sensor which has been used to provide information on the time structure at the nanosecond level of a clinical proton beam. Materials and methods: A 3 × 3 × 3 mm3 plastic scintillator (EJ‐232Q Eljen Technology) coupled to a 3 × 3 mm2 SiPM (MicroFJ‐SMA‐30035, Onsemi) has been characterized with a 70 MeV clinical proton beam accelerated in a Proteus One synchrocyclotron. The signal was read out by a high sampling rate oscilloscope (5 GS/s). By exposing the sensor directly to the proton beam, the time beam profile of individual spots was recorded. Results: Measurements of detector signal have been obtained with a time sampling period of 0.8 ns. Proton bunch period (16 ns), spot (10 μs) and interspot (1 ms) time structures could be observed in the time profile of the detector signal amplitude. From this, the RF frequency of the accelerator has been extracted, which is found to be 64 MHz. Conclusions: The proposed system was able to measure the fine time structure of a clinical proton accelerator online and with ns time resolution. [ABSTRACT FROM AUTHOR]

This study outlines a concept that would leverage the existing proton accelerator at the Spallation Neutron Source (SNS) of Oak Ridge National Laboratory to enable transformative science via one world-class facility serving two missions: Single Event Effects (SEE) and Muon Spectroscopy (μSR). The μSR portion would deliver the world's highest flux and highest resolution pulsed muon beams for material characterization purposes, with precision and capabilities well beyond comparable facilities. The SEE capabilities deliver neutron, proton, and muon beams for aerospace industries that are facing an impending challenge to certify equipment for safe and reliable behavior under bombardment from atmospheric radiation originating from cosmic and solar rays. With negligible impact on the primary neutron scattering mission of the SNS, the proposed facility will have enormous benefits for both science and industry. We have designated this facility "SEEMS." [ABSTRACT FROM AUTHOR]

Proton irradiation experiments have been used as a surrogate for studying radiation effects in numerous materials for decades. The abundance and accessibility of proton accelerators make this approach convenient for conducting accelerated radiation ageing studies. However, developing new materials with improved radiation stability requires numerous model materials, test samples, and very effective utilization of the accelerator beam time. Therefore, the question of optimal beam current, or particle flux, is critical and needs to be adequately understood. In this work, we used 5 MeV protons to introduce displacement damage in gallium arsenide samples using a wide range of flux values. Positron annihilation lifetime spectroscopy was used to quantitatively assess the concentration of radiation-induced survived vacancies. The results show that proton fluxes in range between 1011 and 1012 cm−2.s−1 lead to a similar concentration of monovacancies generated in the GaAs semiconductor material, while a further increase in the flux leads to a sharp drop in this concentration. [ABSTRACT FROM AUTHOR]

During acceleration of particles with a charge-to-mass ratio of 1 : 2, the length of a cavity is practically doubled compared to that of a proton accelerator for the same energy. At an output energy exceeding 1.0 MeV per nucleon, the cavity length becomes large, Lcav ≈ 3λ, where λ is the wavelength of the TE211 operating mode. This leads to a critically small frequency separation between the operating TE211 quadrupole mode and the TE11n dipole modes. For mode separation, it is proposed to use coupling windows in the electrodes between neighboring structure segments, which in turn change the field distribution along the structure. Field uniformity is restored with the insertion of plungers into the four segments between the electrodes through the RFQ shell. The result of the simulation is a tuned RFQ accelerating structure with the following main parameters: the ion type is deuterons D+ or alpha particle He++, the operating frequency is 202 MHz, the injection voltage is 75 kV, the length is 4.3 m, the peak RF power is not higher than 300 kW, the energy of accelerated ions is 1.25 MeV/nucleon, and the peak current is 50 mA for D+ and 10 mA for He++. The result is the design of the RFQ structure based on the performed electrodynamics and beam dynamics simulation. [ABSTRACT FROM AUTHOR]

A design study, named ESS ν SB for European Spallation Source neutrino Super Beam, has been carried out during the years 2018–2022 of how the 5 MW proton linear accelerator of the European Spallation Source under construction in Lund, Sweden, can be used to produce the world's most intense long-baseline neutrino beam. The high beam intensity will allow for measuring the neutrino oscillations near the second oscillation maximum at which the CP violation signal is close to three times higher than at the first maximum, where other experiments measure. This will enable CP violation discovery in the leptonic sector for a wider range of values of the CP violating phase δ CP and, in particular, a higher precision measurement of δ CP . The present Conceptual Design Report describes the results of the design study of the required upgrade of the ESS linac, of the accumulator ring used to compress the linac pulses from 2.86 ms to 1.2 μs, and of the target station, where the 5 MW proton beam is used to produce the intense neutrino beam. It also presents the design of the near detector, which is used to monitor the neutrino beam as well as to measure neutrino cross sections, and of the large underground far detector located 360 km from ESS, where the magnitude of the oscillation appearance of ν e from ν μ is measured. The physics performance of the ESS ν SB research facility has been evaluated demonstrating that after 10 years of data-taking, leptonic CP violation can be detected with more than 5 standard deviation significance over 70% of the range of values that the CP violation phase angle δ CP can take and that δ CP can be measured with a standard error less than 8° irrespective of the measured value of δ CP . These results demonstrate the uniquely high physics performance of the proposed ESS ν SB research facility. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to evaluate the clinical infrastructure and utilization of radiotherapy (RT) services in Korea between 2017 and 2019. Materials and Methods: We extracted the data of patients who underwent RT between 2017 and 2019 from the Health Insurance Review and Assessment Service. We further analyzed this data according to the diagnosis and treatment modalities of patients diagnosed with International Classification of Disease 10 (ICD-10) diagnostic codes C00-C97 and D00-D48. In addition, we collected statistics on RT facilities in Korea using a nationwide survey. Results: The total number of patients who received RT in 2017, 2018, and 2019 were 77,901, 81,849, and 87,460, respectively. The number of patients diagnosed with ICD 10 C- and D-codes in 2019 was 86,339, of whom 39,467 were men and 46,872 women. The rate of utilization of RT among cancer patients was 30.4% in 2017 and 2018 and 30.9% in 2019. In 2019, the most common types of cancers treated with RT were breast, lung, prostate, colorectal, and liver cancers. Regarding the RT infrastructure in Korea, there were 95 radiation oncology centers, 237 megavoltage (MV) teletherapy units, 35 brachytherapy units, and two proton accelerators in 2019. There were 4.5 MV teletherapy machines per million. Conclusion: The number of patients treated with RT has increased consistently from 2017 to 2019. As the number of patients with cancer increases, it is expected that the RT infrastructure will be further expanded in Korea. [ABSTRACT FROM AUTHOR]

Nuclide production cross sections for proton-induced reactions on nat Ni and nat Zr at incident energies of 0.4, 1.3, 2.2, and 3.0 GeV were measured by the activation method at Japan Proton Accelerator Research Complex (J-PARC). In total, 24 and 43 residual nuclides were measured for the nat Ni and nat Zr targets, respectively. Among them, the cross sections of the following reactions were measured for the first time: nat Zr(p,x)28Mg, nat Zr(p,x)42K, nat Zr(p,x)43K, nat Zr(p,x) 44g Sc, nat Zr(p,x)55Co, nat Zr(p,x) 69m Zn, and nat Zr(p,x)93Y reactions. To examine the prediction capabilities, the measured data were compared with the spallation reaction models in PHITS (INCL4.6, Bertini, and JAM as intranuclear cascade models, and GEM as an evaporation model), INCL++/ABLA07, semi-empirical calculation code SPACS, and the JENDL/HE-2007 library. From the evaluation introducing the mean square deviation factor, the best reproducibility was exhibited by the JENDL/HE-2007 library for nat Ni and INCL++/ABLA07 for nat Zr. [ABSTRACT FROM AUTHOR]

We describe in detail an Ultra High Dose Rate (UHDR) setup on a 2 MV tandem accelerator for investigating the FLASH effect in radiotherapy. Addressing UHDR dosimetry challenges, we have developed a specialized Faraday Cup (FC) as a dose rate-independent solution. Utilizing Monte Carlo simulations, the geometry and materials used for the FC's design has been optimized for a 4 MeV proton beam. According to the simulations, the virtual error on the charge collection is negligible. This three-part UHDR setup also integrates a beam profiler to ensure the beam homogeneity and an electrostatic chopper to irradiate for precise short times (down to 10 μs), replicating the macro beam structure of typical clinical proton accelerator structures such as the S2C2 and C230 (IBA, Louvain-la-Neuve). The integrated setup ensures dose deposition with an error ≤ 5% for dose rate from 140 to 1000 Gy/s. [ABSTRACT FROM AUTHOR]

The PREF project (Proton Radiation Effects Facility) aims to provide low to medium energy protons from 10–60 MeV, which is an excellent range for experimental research on the displacement damage effect studies of satellites and payload components, and is currently under construction in China. Average proton beam fluxes range from tens of particles/( cm 2 s) up to approximately 1 0 8 particles/( cm 2 s), spot sizes after scanning range from 2 × 2 cm 2 to 20 × 20 cm 2 , and uniformity is better than 95%. It comprises a 2.45 GHz ion source, a 325 MHz four-vane RFQ linac injector, a compact synchrotron, and two irradiation terminals. Protons will be injected into synchrotron using multi-turn injection scheme to obtain high-gain beam accumulation. The third-order resonance slow extraction scheme is adopted to achieve high efficiency and continuous uniform extraction of the beam for irradiation experiments. Several innovative accelerator technologies such as titanium alloy lined thin-wall vacuum chamber and fast ramping rate full energy storage power supply are also adopted. In this paper, the general design and simulation results of the accelerator complex are presented, and the new technology and progress of the PREF project are briefly introduced. [ABSTRACT FROM AUTHOR]

• We analyzed differences in the effects induced by cranial exposure to protons or photons in a radiosensitive mouse model to identify and mechanistically understand differences in their biology. • Approximately the same apoptotic levels after protons or photons suggest a comparable early cellular response of the cerebellum to the two radiation types. • Similar kinetics of MB development were induced following irradiation with 3 Gy of protons or photons. Lens sparing by protons was observed, consistent with their physical properties. • Changes in expression of neurogenesis genes in hippocampus of similarly treated WT mice were radiation type-specific, mainly involving synaptic plasticity for protons and angiogenesis for photons. Notably, different features in neuroinflammation were observed, prevalently astrogliosis for protons and microgliosis for photons. Medulloblastoma (MB) is a common primary brain cancer in children. Proton therapy in pediatric MB is intensively studied and widely adopted. Compared to photon, proton radiations offer potential for reduced toxicity due to the characteristic Bragg Peak at the end of their path in tissue. The aim of this study was to compare the effects of irradiation with the same dose of protons or photons in Patched1 heterozygous knockout mice, a murine model predisposed to cancer and non-cancer radiogenic pathologies, including MB and lens opacity. TOP-IMPLART is a pulsed linear proton accelerator for proton therapy applications. We compared the long-term health effects of 3 Gy of protons or photons in neonatal mice exposed at postnatal day 2, during a peculiarly susceptible developmental phase of the cerebellum, lens, and hippocampus, to genotoxic stress. Experimental testing of the 5 mm Spread-Out Bragg Peak (SOBP) proton beam, through evaluation of apoptotic response, confirmed that both cerebellum and hippocampus were within the SOBP irradiation field. While no differences in MB induction were observed after irradiation with protons or photons, lens opacity examination confirmed sparing of the lens after proton exposure. Marked differences in expression of neurogenesis-related genes and in neuroinflammation, but not in hippocampal neurogenesis, were observed after irradiation of wild-type mice with both radiation types. Conclusion. In-vivo experiments with radiosensitive mouse models improve our mechanistic understanding of the dependence of brain damage on radiation quality, thus having important implications in translational research. [ABSTRACT FROM AUTHOR]

The hydrophilic hollow construction of HZIF-8 enhanced the water retention of composite membrane and reduced the proton transfer resistance throughout HZIF-8. More importantly, the proton conducting routes at both the GO@HZIF-8 surfaces and GO@HZIF-8/Nafion interfaces became relatively connective benefitting from the tethering function of GO. These combinedly resulted in outstanding proton transportation ability of composite membrane. [Display omitted] • GO@HZIF-8 was constructed as an efficient proton transfer accelerator. • Proton transfer of composite PEM was effectively accelerated by GO@HZIF-8. • Composite PEM exhibited distinctly promoted fuel blocking ability. • Maximum current density and power density of composite PEM were greatly improved. Interconnected hollow metal–organic framework (MOF) network (GO@HZIF-8) was designed as an efficient proton transfer accelerator in Nafion membrane. GO@HZIF-8 was constructed by in situ synthesis of ZIF-8 onto graphene oxide (GO) and succedent etching with tannic acid (TA). The hollow construction and surface TA functionalization of hollow ZIF-8 (HZIF-8) bestowed composite membrane with superior water retention. This was highly beneficial to the rapid proton transfer. Besides, the hollow construction could effectively reduce the proton transfer resistance onto GO@HZIF-8. More importantly, the interconnective architecture between HZIF-8 by the tethering function of GO and the interfacial hydrogen bond interaction between GO@HZIF-8 and Nafion resulted in connective proton transfer routes at GO@HZIF-8 surfaces and GO@HZIF-8/Nafion interfaces. These dramatically accelerated the proton transfer of GO@HZIF-8/Nafion composite membrane, enabling a considerable proton conductivity (PC) of 0.301 S cm−1 under 90 °C, 95 % RH, ∼1.33-fold greater than that of the pure Nafion membrane (RN). Moreover, the composite membrane exhibited a peak power density of 45.8 mW cm−2, ∼1.22-fold higher than that of RN. These results menifest that constructing hollow MOF network possesses grand prospect in the construction of high performance proton exchange membranes (PEMs). [ABSTRACT FROM AUTHOR]

Boron Neutron Capture Therapy (BNCT) is a radiotherapy whose effect is due to the combination of low-energy neutron irradiation prior chemical targeting of tumour tissues with boron-10. The context of this work is the design of a clinical BNCT facility based on a Radio-Frequency Quadrupole proton accelerator, manufactured by the Italian National Institute of Nuclear Physics (INFN). Such a machine can provide a neutron beam suitable for the treatment of deep-seated tumours when coupled to a beryllium target and a Beam Shaping Assembly whose main constituent is densified lithiated aluminium fluoride. This paper refines the design of the facility, already addressed in preliminary studies, from the point of view of dosimetric quantities in the room and in the patient. The presented calculations have been performed with different Monte Carlo codes, and assess the time evolution of the dose due to the neutron activation of the irradiated materials. A comprehensive evaluation of the dose absorbed in the healthy organs of the patient is provided, with focus on the residual radioactivity of the patient urine, for three different treatment positions. Borated concrete is confirmed to be the best material for constructing the walls of the treatment room. A lead shielding at the beam-port is proposed to reduce the gamma dose at the irradiation position due to the activation of the Beam Shaping Assembly. • Calculations of activation and dosimetry help in designing the treatment room. • Radiation protection is pivotal for the design of a BNCT facility. • Borated concrete walls reduce the activation of tissues and urine. • Borated concrete walls reduce the ambient dose due the neutron activation. • A beamport shield decreases ambient dose due to materials activation. [ABSTRACT FROM AUTHOR]

A sample-motion-synchronized neutron stroboscope is developed using the RIKEN accelerator-based compact neutron source (RANS). When a sample reaches a specified rotation phase, a phase timing signal is generated, triggering a proton pulse at the proton accelerator. A neutron pulse exposes the imaging detector through the sample. By controlling the delay time between the phase signal and the proton pulse timing, the neutron exposure timing is always synchronized with the specific sample rotation phase. A sample rotating at a speed of 1800 RPM is prepared, and clear still images of neutrons are taken. [ABSTRACT FROM AUTHOR]

The Japan Proton Accelerator Research Complex (J-PARC) is a hadron-accelerator facility that aims to provide secondary beams of kaons, pions, neutrinos, muons, and others together with the primary proton beam for investigating a wide range of science projects. High-energy hadron physics can be studied by using high-momentum beams of unseparated hadrons, which are essentially pions, and also primary protons. In this report, possible experiments are explained on color transparency and generalized parton distributions (GPDs). These projects are complementary to lepton-scattering experiments at Jefferson Laboratory (JLab), COMPASS/AMBER, and future electron-ion colliders. Thank to hadron-beam energies up to 30 GeV, J-PARC is a unique facility to investigate the transition region from the hadron degrees of freedom to the quark-gluon degrees of freedom. It is suitable for finding mechanisms of the olor transparency. Such color-transparency studies are also valuable for clarifying the factorization of hadron production processes in extracting the GPDs from actual measurements. These studies will lead to the understanding of basic high-energy hadron interactions in nuclear medium and to clarifications on the origins of hadron spins, masses, and internal pressure mechanisms. [ABSTRACT FROM AUTHOR]

Elemental analysis based on muonic X-rays resulting from muon irradiation provides information about bulk material composition without causing damage, which is essential in the case of precious or otherwise unreachable samples, such as in archeology and planetary science. We developed a three-dimensional (3D) elemental analysis technique by combining the elemental analysis method based on negative muons with an imaging cadmium telluride double-sided strip detector (CdTe-DSD) designed for the hard X-ray and soft γ -ray observation. A muon irradiation experiment using spherical plastic samples was conducted at the Japan Proton Accelerator Research Complex (J-PARC); a set of projection images was taken by the CdTe-DSD, equipped with a pinhole collimator, for different sample rotation angles. The projection images measured by the CdTe-DSD were utilized to obtain a 3D volumetric phantom by using the maximum likelihood expectation maximization algorithm. The reconstructed phantom successfully revealed the 3D distribution of carbon in the bulk samples and the stopping depth of the muons. This result demonstrated the feasibility of the proposed non-destructive 3D elemental analysis method for bulk material analysis based on muonic X-rays. [ABSTRACT FROM AUTHOR]

To build a proton beam accelerator that can be applied to a boron neutron capture therapy system based on an electrostatic accelerator, a high-voltage direct-current (DC) power supply system equivalent to the generation of neutrons should be provided. The symmetrical Cockcroft–Walton voltage multiplier method is suitable for stable acceleration of the proton beam in the tandem electrostatic accelerator in this system. Before the second step-up with the Cockcroft–Walton circuit, the design of the inverter is prioritized by preponderantly considering the first voltage and resonance frequency. Moreover, the optimized stacking number is determined with consideration of the ripple voltage, voltage drop, average output voltage, and fundamental harmonics, and a design is performed to set related parameter values to be stable in the flat-top region of the voltage. A high-voltage DC power supply system of 1.2 MV/45 mA is needed for a stable terminal energy of 2.4 MeV/20 mA. Such a design can be optimized by securing reliable data using a simulation tool on the basis of theoretical calculations. This will become a formidable touchstone in manufacturing technology based on acquiring practical know-how for setting up a tandem electrostatic accelerator-based boron neutron capture therapy system in the future. [ABSTRACT FROM AUTHOR]

A concept of a project of compact neutron source (CNS), dedicated for academical research and industrial application (DARIA), is presented. Several versions of neutron source optimization aimed at increasing the neutron flux and luminosity on a sample are considered. A new approach aimed at designing CNS DARIA is formulated: from a sample to a proton source. Thus, with allowance for the real physical and technical limitations, all CNS elements (proton accelerator, target–moderator–reflector (TMR) assembly, moderators, and neutron stations) are optimized as a whole, and each channel leading to the neutron scattering system is optimized separately as well. The complex of neutron systems includes an inverse-geometry spectrometer, an epithermal diffractometer, a system of small-angle neutron scattering (SANS), and a multispectral diffractometer. The results of calculating the TMR assembly are presented. Starting points for further optimization are established. The advantages and drawbacks of pulsed and cw linear accelerators are described, and the optimal parameters of proton accelerator for CNS DARIA are chosen. [ABSTRACT FROM AUTHOR]

This study aimed to identify the optimal conditions for delivering sufficient doses to deep-seated lesions within short irradiation times for two boron carriers of different T / N ratios. The therapeutic depth and irradiation time of a neutron beam for beam shaping assemblies (BSAs) with a Li or Be target and a MgF 2 or CaF 2 moderator were examined with the fast-neutron dose per epithermal neutron (FNR) as a parameter. When T / N = 3.61, the therapeutic depth was almost saturated at an FNR of about 10 × 10−13 Gy cm2; when the FNR value was about 10 × 10−13 Gy cm2, the therapeutic depth of the neutron beam for the BSA with a Be target and a MgF 2 moderator was almost identical to that for the neutron beam for the BSA with a Be target and a CaF 2 moderator, and slightly greater than those for the neutron beams for the BSAs with a Li target and a MgF 2 or CaF 2 moderator; moreover, the irradiation time of the neutron beam for the BSA with a Be target and a MgF 2 moderator was shorter than that for the neutron beam for the BSA with a Be target and a CaF 2 moderator. When T / N = 100, the therapeutic depths of the neutron beams for the BSAs varied greatly depending on the FNR, and were greater than the corresponding values for T / N = 3.61. We therefore concluded that the BSA with a Be target and a MgF 2 moderator that produced a neutron beam with an FNR of about 10 × 10−13 Gy cm2 is optimal for delivering sufficient doses to deep-seated lesions in short irradiation times when T / N = 3.61, and stricter control over FNR is required when T / N = 100. • Beam shaping assemblies (BSAs) for AB-BNCT were designed when T / N = 3.61. • The BSA models included a Li or Be target and a MgF 2 or CaF 2 moderator. • The beam had a fast-neutron dose per epithermal neutron (FNR) as a parameter. • The BSA with a Be target and a MgF 2 moderator maximized the therapeutic depth. • The BSA with a Be target and a MgF 2 moderator minimized the irradiation time. [ABSTRACT FROM AUTHOR]

The study focuses on the investigation of induced radioactivity resulting from the operation of a proton therapy accelerator which poses an enduring risk to both staff and the public. Therefore, it is imperative to conduct research on this topic. The Monte Carlo code FLUKA is utilized to study the residual dose rate of a 250 MeV proton therapy accelerator under various operational and cooling durations, as well as the types and specific activities of radionuclides produced in the structural components, concrete walls, cooling water, cooling water pipe, soil, and underground water. The findings indicate that after continuous operation for 100 days followed by a 1-h cooling, the residual dose rate at the distance of 30 cm from the surface of the structural components is 0.98 mSv/h. At this point, maintenance personnel can safely enter the hall. During emergency equipment maintenance after shutdown, it's advised to keep maintenance personnel at least 1 m away. After 30 years, cooling water, soil, and underground water meet exemption requirements. Air and concrete walls necessitate cooling for 30 min and 3 days, respectively. Directly exemption cannot be granted for metal components due to long-lived nuclides present in these materials, such as 60Co which takes over several years to decay to safe levels. Consequently, highly activated metal components require remote disassembly and storage. • Conducted a study on proton therapy accelerator-induced radioactivity by FLUKA. • Analyzed the residual dose distribution and variation after 100 days of operation. • The activity of radionuclides in components after decommissioning is given. • Given some suggestions on reducing the hazards of people's induced radioactivity. [ABSTRACT FROM AUTHOR]

Development of non-destructive analysis systems at the R&D beamline of the Proton Accelerator Facility of the Turkish Energy, Nuclear and Minerals Research Agency (TENMAK-PAF) is described in this work. The proton beam from the cyclotron with energy between 15–30 MeV and current between 0.1 μ A–1.2 mA is modified with several components and subsystems to be suitable for the application of non-destructive analysis methods. Certified reference materials (CRM) and samples with different properties were irradiated under vacuum in the irradiation chamber with the new system. Particle Induced X-ray Emission (PIXE) and Particle Induced Gamma ray Emission (PIGE) spectra of these samples were obtained with appropriate radiation detectors and measurement systems. The results of PIXE analyses and X-ray fluorescence (XRF) spectrometry were compared. PIXE and PIGE results are in good agreement with the certified values for the CRMs. This work constitutes the first reported application of non-destructive ion beam analysis methods in TENMAK-PAF and in Türkiye. • Cyclotrons, mainly used for radioisotope production, have been used for non-destructive analysis methods. • Non-destructive ion beam analysis methods are implemented for the first time in TENMAK-PAF and in Türkiye. • Proton beam irradiation is performed with pA current and 2–3 MeV energies in medical cyclotron. • Measurement system for PIXE, PIGE and RBS has been installed at TENMAK-PAF. [ABSTRACT FROM AUTHOR]

A repetitive pulsed power supply prototype has been designed and implemented for the RCS beam extraction kicker in the CSNS upgrade. The pulsed power supply features an ultra-low impedance Blumlein PFN to generate a fast front and high-current pulse, and a saturable magnetic switch to sharpen the pulse's rising edge at the nanosecond time scale. A detailed report is provided on the practical engineering issues arising from the ultra-low impedance Blumlein PFN in the paper. Additionally, we have utilized simulation and experimental methods to evaluate the effectiveness of the saturation magnetic switch in sharpening the excitation current at the nanosecond time scale. The developed pulsed power supply is capable of generating a pulse current of 6660 A with a rise time of 248 ns, a pulse flat-top duration of 628 ns, a time jitter of ±4.5 ns, and a flat-top ripple of ≤±1 % at a repetition rate of 25 Hz. The design and experimental results of this pulsed power supply are presented in detail in this paper. [ABSTRACT FROM AUTHOR]

Nuclide production cross sections for proton-induced reactions on nat Mg, nat Si, nat Fe, nat Cu, and nat Zn at several GeV were measured using an activation technique at Japan Proton Accelerator Research Complex. The aggregate results of 250 cross sections were successfully acquired. The cross sections of the nat Fe(p,X) 44m Sc, nat Zn(p,X)22Na, nat Zn(p,X)28Mg, nat Zn(p,X)48Sc, and nat Zn(p,X) 69m Zn reactions were acquired for the first time. The cross sections of the nat Fe(p,X)46Sc, nat Fe(p,X)52Fe, nat Cu(p,X)43Sc, nat Cu(p,X)48Sc, nat Cu(p,X)58Co, and most of the nat Zn(p,X) reactions above about 1 GeV were firstly measured. The data obtained in this study were compared with the results from nuclear reaction models in PHITS and the data retrieved from Japanese Evaluated Nuclear Data Library High Energy file 2007 (JENDL/HE-2007). As the nuclear reaction models, Liège IntraNuclear Cascade, two versions of JAERI Quantum Molecular Dynamics, and Jet AA Microscopic Transport Model coupled with an evaporation process were applied. Among all of the models, INCL/GEM, JENDL/HE-2007, and JAM/GEM generally showed the good agreement. [ABSTRACT FROM AUTHOR]

This work presents a preliminary safety analysis of the accelerator-driven system under development at TRANSMUTEX. It is a sub-critical lead-cooled fast reactor with a nominal power of 300 MW t h having the following features: (1) an inert-matrix fuel; (2) a k e f f = 0.974; (3) a heavy metal spallation target; and (4) a 4 MW proton accelerator. The safety analyses are based on the GeN-Foam multi-physics code, whose point-kinetics sub-solver has been extended for the analysis of sub-critical reactor configurations. In the paper, we first present the extension of the code and its verification against analytical results. Then, we present the results of our preliminary safety analysis, including in particular the simulation of various unprotected (double-fault) accidental transients. [ABSTRACT FROM AUTHOR]

Nuclide production cross sections for proton-induced reactions on Mn and Co at incident energies of 1.3, 2.2, and 3.0 GeV were measured by the activation method at the Japan Proton Accelerator Research Complex (J-PARC). In total, 143 production cross sections of reaction products with half-lives ranging from 1.8 h to 2.6 yr were obtained. Among them, the cross sections of 55Mn(p,x)38S, 55Mn(p,x)41Ar, and 59Co(p,x)38S reactions were measured for the first time. The stable proton beam and well-established beam profile-motoring system contributed to the reduction of the systematic uncertainties to typically less than 5%, which was better than those of the previous data (typically ∼ 10%). To examine the prediction capabilities of spallation reaction models and evaluated nuclear data library, the measured data were compared with the spallation reaction models in PHITS (INCL4.6, Bertini, and JAM as intranuclear cascade models, and GEM as an evaporation model), INCL++/ABLA07, and the JENDL/HE-2007 library. The comparison of the mean square deviation factors indicated that both INCL4.6/GEM and JENDL/HE-2007 showed better agreement with the measured data than the others. [ABSTRACT FROM AUTHOR]

We report on silicon carbide (SiC) p-n junction diodes with a high blocking voltage over 3 kV. Although SiC radiation sensors have been developed with a Schottky barrier type due to a simple fabrication process in the early stages, p-n junction structures are advantageous due to lower sensitivity of the surface defects. Thus, this system provides an ideal condition to investigate the effect of bulk crystal defects on the characteristics of the radiation sensor. The p-n diodes were designed with a device simulator and fabricated with a 4-in 4H-SiC wafer. The epitaxial layer was grown on an n-type substrate with sufficiently low doping concentration of ${N_{\mathrm{ d}}} - {N_{\mathrm{ a}}}=\sim 5\times 10^{14} {\mathrm{ cm}}^{-3}$ and an average thickness of $52 ~\mu {\mathrm{ m}}$. Fabricated p-n diodes with a relatively large leakage current still show a clear peak of the Landau distribution in the charge spectrum, suggesting their practical availability as minimum ionizing particle (MIP) detectors. The estimated electron–hole pair creation energy is consistent with the published studies and we expect good radiation tolerance. Feasibility based on the wafer processing indicates that the prototype devices are a good candidate for the muon beam monitor application in the COherent Muon-to-Electron Transition (COMET) experiment at Japan Proton Accelerator Research Complex (J-PARC). [ABSTRACT FROM AUTHOR]

In a medical accelerator, real-time monitoring systems of the beam and dose delivered to the patient are mandatory. In this work, we present a compact current profile detector that has been designed and tested in the framework of the TOP-IMPLART (Intensity Modulated Proton Linear Accelerator for RadioTerapy) project. This project foresees the realization of a proton linear accelerator, currently under construction at ENEA Frascati, for proton therapy applications. The linac produces a pulsed proton beam with 3 µs duration at 50 Hz repetition rate with a pulse current between 0.5 and 50 μA. A large dynamic range and spatial constraints make the use of usual noninterceptive beam diagnostics unfeasible. Therefore, the use of a beam current monitor based on a passive RF cavity working in the TM010 mode has been proposed. This paper reports the electromagnetic design of the device guided by a simplified analytical model. A prototype of such a device has been realized, characterized, and tested on the linac with a 35 MeV beam varying the beam current. The test results in air and in vacuum, together with the signal detection systems used, are presented. [ABSTRACT FROM AUTHOR]

One method to implement undulator acceleration is to move particles in a magnetic undulator, in which the particle spatial oscillations in the transverse direction are synchronized with the frequency of the transverse radio frequency field, which allows transferring the field energy to the accelerated particle. Since resonators that allow obtaining a uniform transverse field are structurally simpler than those with a periodically varying longitudinal radio frequency field, undulator accelerators are an attractive alternative to traditional accelerators. Although the physical fundamentals of such accelerators were described earlier in the literature, the problem of creating their prototypes still remains unsolved. In this paper, a practical description of a prototype proton undulator linear accelerator based on this principle, which is under development at RadiaBeam Technologies LLC (United States) is presented. [ABSTRACT FROM AUTHOR]