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The study of the processes and mechanisms of the medium group mass nuclear systems formation (formed in reactions with protons) has both an important fundamental and practical significance. These tasks are especially important for the production of medical radionuclides, which are used for the effective early diagnosis and treatment of the various cancers. Combining the methods of radionuclide imaging with the methods of radionuclide therapy (therapy plus diagnostics—theranostics), it is possible to implement unique methods of non-surgical treatment of tumors with their precise visualization and minimal side effects. Therefore, in this work the experimental and theoretical studies of the nuclear reaction excitation functions with targets: 117Sn and 119Sn in the proton energy range of 6–18 MeV are carried out. Cross sections of the formation of antimony radionuclides are obtained for these reactions, and the mechanisms of such reactions are analyzed. Antimony radionuclides are promising for use in theranostics.

Differential cross sections for gamma-ray emission from the 107Ag (p, p′γ3-0)107Ag and 109Ag (p, p′γ3-0)109Ag reactions in the proton energy range 1200–2700 keV were measured at 90⁰ in the laboratory frame. In addition, differential cross sections for gamma-ray emission from the 107Ag(p, p′γ4-0)107Ag and 109Ag(p,p′γ4-0)109Ag reactions in the proton energy range 1310–2700 keV and 1330–2700 keV in the mentioned condition. The measurements were performed using the proton beam of the 3 MV Van de Graaff electrostatic accelerator of Nuclear Science and Technology Research Institute (NSTRI) in Tehran. Besides, the validity of the measured differential cross sections was verified through comparison between calculated thick target yields deduced from present work excitation curve and experimental thick target yield data available from literature. The overall systematic uncertainty of the measured values was estimated to be less than 8%.

A high-intensity pulsed neutron source can be constructed according to the principle of a superbooster, i.e., a neutron multiplying system of the neutron-generating target of the proton accelerator with proton energy of about 1 GeV in the subcritical reactivity modulation system. Usually, superboosters are considered to be safe and reliable nuclear facilities. However, as indicated in this paper, a powerful superbooster may prove to be less stable in operation than a pulsed reactor. Therefore, the problems of its safety call for close study.

The purpose of this study was to parametrize the in-air one sigma spot size for various energies and air gaps in pencil beam scanning (PBS) proton therapy. The current study included range shifters with a water equivalent thickness (WET) of 40 mm (RS40) and 75 mm (RS75). For RS40, the spot sizes were measured for energies ranging from 80 to 225 MeV in increments of 2.5 MeV, whereas the air gap was varied from 5 to 25 cm in increments of 2.5 cm. For RS75, the spot sizes were measured for energies ranging from 120 to 225 MeV in increments of 2.5 MeV, whereas the air gap was varied from 5 to 35 cm in increments of 2.5 cm. For both RS40 and RS75, all measurements (n = 1090) were acquired at the isocenter using a Lynx 2D scintillation detector. For RS40, the spot sizes increased from 3.1 mm to 10.4 mm, whereas the variation in spot sizes for RS75 ranged from 3.3 mm to 13.1 mm. For each range shifter, an analytical equation demonstrating the relationship of the spot size with the proton energy and air gap was obtained. The best parametrization results were obtained with the 3rd degree polynomial fits of the energy and air gap parameters. The average difference between the modeled and measured spot sizes was 0.0 ± 0.1 mm (range, − 0.24–0.21 mm) for RS40, and 0.0 ± 0.1 mm (range, − 0.23–0.15 mm) for RS75. In conclusion, the analytical model agrees within ± 0.25 mm of the measured spot sizes on a ProteusPLUS PBS proton system with a PBS dedicated nozzle.

Purpose The objective of this study was to evaluate the impact of the magnetic field regulation in conjunction with the volumetric repainting technique on the spot positions and range in pencil beam scanning proton therapy. Methods “Field regulation” — a feature to reduce the switching time between layers by applying a magnetic field setpoint (instead of a current setpoint) has been implemented on the proton beam delivery system at the Miami Cancer Institute. To investigate the impact of field regulation for the volumetric repainting technique, several spot maps were generated with beam delivery sequence in both directions, that is, irradiating from the deepest layer to the most proximal layer (“down” direction) as well as irradiating from the most proximal layer to the deepest layer (“up” direction). Range measurements were performed using a multi‐layer ionization chamber array. Spot positions were measured using two‐dimensional and three‐dimensional scintillation detectors. For range and central‐axis spot position, spot maps were delivered for energies ranging from 70–225 MeV. For off‐axis spot positions, the maps were delivered for high‐, medium, and low‐energies at eight different gantry angles. The results were then compared between the “up” and “down” directions. Results The average difference in range for given energy between “up” and “down” directions was 0.0 ± 0.1 mm. The off‐axis spot position results showed that 846/864 of the spots were within ±1 mm, and all off‐axis spot positions were within ±1.2 mm. For spots (n = 126) at the isocenter, the evaluation between “up” and “down” directions for given energy showed the spot position difference within ±0.25 mm. At the nozzle entrance, the average differences in X and Y positions for given energy were 0.0 ± 0.2 mm and −0.0 ± 0.4 mm, respectively. At the nozzle exit, the average differences in X and Y positions for given energy were 0.0 ± 0.1 mm and −0.1 ± 0.1 mm, respectively. Conclusion The volumetric repainting technique in magnetic field regulation mode resulted in acceptable spot position and range differences for our beam delivery system. The range differences were found to be within ±1 mm (TG224). For the spot positions (TG224: ±1 mm), the central axis measurements were within ±1 mm, whereas for the off‐axis measurements, 97.9% of the spots were within ±1 mm, and all spots were within ±1.2 mm.

An R-matrix analysis is performed for experimental data on 9Be(p,p0)9Be, 9Be(p,p1)9Be* (1.670 MeV), 9Be(p,p2)9Be* (2.430 MeV), 9Be(p,n0)9B, 9Be(p,d0)8Be, 9Be(p,α0)6Li, 9Be(p,α2)6Li* (3.5618 MeV), and 7Li(3He,p0)9Be reactions at 6.5–19.5 MeV excitation energies of 10B compound nucleus. Experimental data on differential and integral cross sections of the 9Be(p,α2)6Li* (3.5618 MeV, Jπ = 0+) reaction at proton energy Ep = 2.3–4.5 MeV are included in the analysis, along with data on differential cross sections of the 9Be(p,n0)9B reaction at angle 0° in the Ep = 2.2–3.5 MeV energy range. New 10B levels are determined and characteristics of states detected earlier are improved.

The secondary proton polarization and differential cross sections of the ( $$p,p^{\prime}$$ ) inelastic reaction on nuclei $${}^{9}$$ Be and $${}^{90}$$ Zr at the initial proton energy of 1 GeV were measured over a wide range of the scattered proton momenta at a laboratory angle of $$\Theta=21^{\circ}$$ . Scattered protons were detected by means of the magnetic spectrometer equipped with a polarimeter based on multiwire proportional chambers and carbon analyzer. A structure in the polarization and cross section data, related probably to the quasielastic scattering off nucleon correlations in the $${}^{9}$$ Be and $${}^{90}$$ Zr nuclei, was observed as earlier in the same data for the $${}^{12}$$ C, $${}^{28}$$ Si, $${}^{40}$$ Ca and $${}^{56}$$ Fe nuclei. A difference in the momentum distributions of the scattering cross section ratios for the $${}^{90}$$ Zr and $${}^{12}$$ C nuclei and for the $${}^{90}$$ Zr and $${}^{9}$$ Be nuclei was observed.

Nuclear reaction model codes like the EMPIRE-3.2, the ALICE-1991 and the TALYS-1.9 have been used to calculate the excitation functions of 63Cu(p,n)63Zn, 65Cu(p,n)65Zn, 66Zn(p,n)66Ga, 67Zn(p,n)67Ga, 67Zn(p,2n)66Ga, 68Zn(p,n)68Ga and 68Zn(p,2n)67Ga reactions for incident proton energy range of 1–80 MeV. These codes compute reaction cross section using the direct, the compound and the pre-equilibrium (PEQ) processes as major nuclear reaction mechanisms. The computed results have been analyzed and compared with the available experimentally measured data and with the evaluated nuclear data files. Good agreements have been found between theoretically calculated and measured data.

We studied the excitation functions of 59Co(p,x) reactions and measured the production cross-sections of medical radioisotopes (57Ni, 55,57,58Co, 54Mn, 51Cr) and other by-products (56Ni, 56Co, 56Mn) from their threshold to a proton energy of 43.7 MeV. The stacked-foil activation method was employed to irradiate the samples with an external beam from the MC-50 cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS), Korea. Off-line γ-ray spectrometry was used to measure the activities of the produced radionuclides. The integral yields for the thick target of the investigated radionuclides were also calculated from the measured excitation functions. The measured results were compared with the literature data as well as with theoretical values obtained from the TENDL-2017 library based on the TALYS-1.9 code.

The dehydroxylation mechanism of mica is studied using IR spectroscopy; x-ray structure and thermodynamic analysis; and kinetic, quantum-mechanical, and quantum-chemical methods. Dehydroxylation is shown to involve localization of a proton between two O atoms. A model in which the hydroxyl proton is placed in a double potential well is proposed. The model allows the basic features of mineral dehydroxylation to be revealed. The proton energy increases if the mineral is heated so that the barrier becomes more transparent. The probability of a particle transitioning through the barrier owing to a tunnel effect is considered. The change of this probability defines the dehydroxylation process.

In this document we present the calculation and experimental validation of a source term for ${}^{18}$F-production with a cyclotron for medical applications operating at 18 MeV proton energy and 30 $\mu$A proton current. The Monte Carlo codes MCNP6 and FLUKA were used for the calculation of the source term. In addition, the radiation field around the $^{18}$O-enriched water target was simulated with the two codes. To validate the radiation field obtained in the simulation, an experimental program has been started using activation samples which are placed close to the water target during an ${}^{18}$F-production run of the cyclotron. After the irradiation, the samples are analyzed and the resulting activation is compared to Monte Carlo calculations of the expected sample activation. We find good agreement between simulations and experimental results, with most calculation to experiment (C/E) ratios well between 0.6 and 1.4., Comment: 16 pages, 7 figures

We present the cross sections for the nat Zn ( p , x ) 67 Cu and nat Zn ( p , x ) 67 Ga reactions within a proton energy range of 47.5–99.2 MeV. We efficiently separated the overlapping gamma-ray spectra of the two isotopes 67 Cu and 67 Ga , using an analytical method without radiochemical separation. The present data were compared with previous data from the literature, typically obtained by radiochemical separation before measuring the gamma-ray spectra of the two isotopes. Our results for the two isotopes generally showed greater or smaller values than those reported in the literature, except for some data concerning partial energy ranges, which were in agreement with the literature data. The present data were also compared with the TENDL-2017 library based on the TALYS code.

At the proton energy of Ep = 7.4 MeV, the double-differential cross sections for the reaction 27Al(p, α1γ)24Mg were measured for 11 values of the alpha-particle emission angle in the range of θα = 30°–160°(lab). All even components of the density-matrix spin-tensors were reconstructed for the oriented 24Mg nucleus in the 2+ state at 1.369 MeV, and the polarization features of this nucleus, including the populations of magnetic sublevels of the nucleus for all spin projections, multipole-moment orientation tensors, and the quadrupole and hexadecapole tensor polarizations, were determined. Relevant experimental results were compared with their counterparts calculated for the triton-pickup mechanism within the coupled-channel method and in the statistical limit of the compound-nucleus model.

Laser-driven ion acceleration has attracted global interest for its potential towards the development of a new generation of compact, low-cost accelerators. Remarkable advances have been seen in recent years with a substantial proton energy increase in experiments, when nanometer-scale ultrathin foil targets and high-contrast intense lasers are applied. However, the exact acceleration dynamics and particularly the ion energy scaling laws in this novel regime are complex and still unclear. Here, we derive a scaling law for the attainable maximum ion energy from such laser-irradiated nanometer-scale foils based on analytical theory and multidimensional particle-in-cell simulations, and further show that this scaling law can be used to accurately describe experimental data over a large range of laser and target parameters on different facilities. This provides crucial references for parameter design and experimentation of the future laser devices towards various potential applications.

The simulation of proton Spread-Out Bragg Peaks (SOBPs) was implemented using the Geant4-based TOPAS Monte Carlo software. Dynamic proton energy switching was implemented using TOPAS time features, while beam weights were calculated using an empirical power law formalism with Bragg peaks spaced by 0.5 mm. To find power parameters yielding flat SOBPs we sampled power parameters for maximum kinetic energies of 50 MeV to 250 MeV and SOBP widths of 15% to 40% of the depth of the distal SOBP end. Simulations were run in a 50 cm cubic water phantom using a uniform squared proton beam. Depth dose was scored along the central axis in a binned cylinder with 1 cm diameter in 2.5 mm increments. Power parameters yielding a flat SOBPs were found to vary with, both energy and SOBP width and differed significantly from previously reported values based on simulations with MCNPX.

Uncertainties in the relative biological effectiveness (RBE) of protons remains a major barrier to the biological optimisation of proton therapy. While a constant value of 1.1 is widely used in treatment planning, extensive preclinical in vitro and in vivo data suggests that proton RBE is variable, depending on proton energy, target tissue, and endpoint. A number of phenomenological models have been developed to try and explain this variation, but agreement between these models is often poor. This has been attributed to both the models’ underlying assumptions and the data to which they are fit. In this brief note, we investigate the underlying trends in these models by comparing their predictions as a function of relevant biological and physical parameters, to determine where models are in conceptual agreement or disagreement. By doing this, it can be seen that the primary differences between models arise from how they handle biological parameters (i.e. α and β from the linear–quadratic model for photon exposures). By contrast, when specifically explored for linear energy transfer-dependence, all models show extremely good correlation. These observations suggest that there is a pressing need for more systematic exploration of biological variation in RBE across different cells in well-controlled conditions to help distinguish between these different models and identify the true behaviour.

Imaging Atmospheric Cherenkov telescopes (IACTs) are designed to detect cosmic gamma rays. As a by-product, IACTs detect Cherenkov flashes generated by millions of hadronic air showers every night. We present the proton energy spectrum from several hundred GeV to several hundred TeV, retrieved from the hadron induced showers detected by the MAGIC telescopes. The protons are discriminated from He and other heavy nuclei by means of using machine learning classification. The energy estimation is based on a specially developed deep neural network regressor. In the last decade, Deep Learning methods gained much interest in the scientific community for their ability to extract complex relations in data and process large datasets in a short time. The proton energy spectrum obtained in this work is compared to the spectra obtained by dedicated cosmic ray experiments.

Laser-driven proton acceleration is a growing field of interest in the high-power laser community. One of the big challenges related to the most routinely used laser-driven ion acceleration mechanism, Target-Normal Sheath Acceleration (TNSA), is to enhance the laser-to-proton energy transfer such as to maximize the proton kinetic energy and number. A way to achieve this is using nanostructured target surfaces in the laser-matter interaction. In this paper, we show that nanowire structures can increase the maximum proton energy by a factor of two, triple the proton temperature and boost the proton numbers, in a campaign performed on the ultra-high contrast 10 TW laser at the Lund Laser Center (LLC). The optimal nanowire length, generating maximum proton energies around 6 MeV, is around 1–2 $$\upmu$$ μ m. This nanowire length is sufficient to form well-defined highly-absorptive NW forests and short enough to minimize the energy loss of hot electrons going through the target bulk. Results are further supported by Particle-In-Cell simulations. Systematically analyzing nanowire length, diameter and gap size, we examine the underlying physical mechanisms that are provoking the enhancement of the longitudinal accelerating electric field. The parameter scan analysis shows that optimizing the spatial gap between the nanowires leads to larger enhancement than by the nanowire diameter and length, through increased electron heating.

L subshell X-rays of 48Cd and 49In have been measured for the impact of protons with energies from 75 to 250 keV. Obviously, it is found that Lγ2 (abbreviation Lγ2,3 for 48Cd and Lγ2,3,4 for 49In) X-ray emission is enhanced in comparison with Lγ1 X-ray emission. The relative intensity ratios of Lγ2 to Lγ1 X-ray are larger than the atomic data and increase with decreasing proton energy. This is caused by the multiple ionization of outer-shell electrons. To verify this explanation, the enhancements for relative intensity ratio of Lι and Lβ2 to Lα X-ray in experiments are discussed, and the direct ionization cross sections of 4d, 5s, and 5p electrons are calculated using BEA theory.

Passive detection of special nuclear material (SNM) is challenging due to its inherently low rate of spontaneous emission of penetrating radiation, the relative ease of shielding, and the fluctuating and frequently overwhelming background. Active interrogation, the use of external radiation to increase the emission rate of characteristic radiation from SNM, has long been considered to be a promising method to overcome those challenges. Current active-interrogation systems that incorporate radiography tend to use bremsstrahlung beams, which can deliver high radiation doses. Low-energy ion-driven nuclear reactions that produce multiple monoenergetic photons may be used as an alternative. The ${}^{12}\mathrm{C}(\mathrm{p},{\mathrm{p}}^{\ensuremath{'}}{)}^{12}\mathrm{C}$ reaction is one such reaction that could produce large yields of highly penetrating 4.4- and 15.1-MeV gamma rays. This reaction does not directly produce neutrons below the approximately 19.7 MeV threshold, and the 15.1-MeV gamma-ray line is well matched to the photofission cross section of ${}^{235}\mathrm{U}$ and ${}^{238}\mathrm{U}$. We report the measurements of thick-target gamma-ray yields at 4.4 and 15.1 MeV from the ${}^{12}\mathrm{C}(\mathrm{p},{\mathrm{p}}^{\ensuremath{'}}{)}^{12}\mathrm{C}$ reaction at proton energies of 19.5, 25, and 30 MeV. Measurements are made with two $3$-in. EJ-309 cylindrical liquid scintillation detectors and thermoluminescent dosimeters placed at ${0}^{\ensuremath{\circ}}$ and ${90}^{\ensuremath{\circ}}$, with an additional $1.5$-in. $\mathrm{Na}\mathrm{I}$($\mathrm{Tl}$) cylindrical scintillation detector at ${0}^{\ensuremath{\circ}}$. We estimate the highest yields of the 4.4- and 15.1-MeV gamma rays of $1.65\ifmmode\times\else\texttimes\fi{}{10}^{10}$ and $4.47\ifmmode\times\else\texttimes\fi{}{10}^{8}\phantom{\rule{0.2em}{0ex}}{\mathrm{sr}}^{\ensuremath{-}1}$ $\ensuremath{\mu}{\mathrm{C}}^{\ensuremath{-}1}$ at a proton energy of 30 MeV, respectively. The yields in all experimental configurations are greater than in a comparable deuteron-driven reaction that produces the same gamma-ray energies---${}^{11}\mathrm{B}(\mathrm{d},\mathrm{n}\ensuremath{\gamma}{)}^{12}\mathrm{C}$. However, a significant increase of the neutron radiation dose accompanies the proton energy increase from 19.5 to 30 MeV.

Positron Emission Tomography/Computed Tomography (PET/CT) modality has been widely used in nuclear medicine for cancer imaging by using fluorine-18 (F-18) or gallium-68 (Ga-68) radionuclides as positron emitters. In this work, we discuss production aspects of F- 18 and Ga-68 radionuclides, PET/CT procedure as well as an example of cancer imaging using F-18 and Ga-68 based PET/CT scan. In terms of radioactivity yields at the same proton energy and proton dose, F-18 shows higher radioactivity yield than Ga-68. Furthermore, examples of cancer imaging using F-18 based PET/CT scan indicate a much clearer image compared to that of Ga-68 based PET/CT scan, though both results are acceptable in nuclear medicine for cancer diagnosis.

We measured the excitation functions for the production of the radionuclides $$^{{95}}\hbox {Zr}$$ , $$^{95\mathrm {m}}\hbox {Nb}$$ and $$^{95\mathrm {g}}\hbox {Nb}$$ from the $$^{\mathrm {nat}}\hbox {Zr}(\hbox {p},\hbox {x})$$ reactions in the proton energy range of 10.6–43.6 MeV. The experiment was performed by irradiation of zirconium and copper foils simultaneously using 45 MeV proton beam from the MC-50 Cyclotron at the Korea Institute of Radiological and Medical Sciences, Korea, and the induced activity was measured with an HPGe $$\upgamma $$ -ray detector. Proton energies along the foil stack were calculated using the computer code SRIM-2013. The proton beam flux entered each foil was determined via the $$^{\mathrm {nat}}\hbox {Cu}(\hbox {p},\hbox {x})^{{62}}\hbox {Zn}$$ and $$^{\mathrm {nat}}\hbox {Cu}(\hbox {p},\hbox {x})^{{65}}\hbox {Zn}$$ monitoring reactions. The cumulative cross sections of the $$^{\mathrm {nat}}\hbox {Zr}(\hbox {p},\hbox {x})^{{95}}\hbox {Zr}$$ reaction were measured because it was unable to separate the activity from the decay of $$^{{95}}\hbox {Y}$$ to $$^{{95}}\hbox {Zr}$$ . However, independent cross sections of the $$^{\mathrm {nat}}\hbox {Zr}(\hbox {p},\hbox {x})^{95\mathrm {m}}\hbox {Nb}$$ and $$^{\mathrm {nat}}\hbox {Zr}(\hbox {p},\hbox {x})^{95\mathrm {g}}\hbox {Nb}$$ reactions were determined, since the independent activities of $$^{95\mathrm {m}}\hbox {Nb}$$ and $$^{95\mathrm {g}}\hbox {Nb}$$ can also be measured. In addition, the thick target yields of the $$^{{95}}\hbox {Zr}$$ , $$^{95\mathrm {m}}\hbox {Nb}$$ and $$^{95\mathrm {g}}\hbox {Nb}$$ isotopes were also determined. The current results are compared with the previously measured data as well as with the theoretical values from the TALYS-1.9 code and the TENDL-2019 data library.

The ion recombination is examined in parallel-plate ionization chambers in scanning proton beams at the Danish Centre for Particle Therapy and the Skandion Clinic. The recombination correction factor k s is investigated for clinically relevant energies between 70 MeV and 244 MeV for dose rates below 400 Gy min-1 in air. The Boutillon formalism is used to separate the initial and general recombination. The general recombination is compared to predictions from the numerical recombination code IonTracks and the initial recombination to the Jaffé theory. k s is furthermore calculated with the two-voltage method (TVM) and extrapolation approaches, in particular the recently proposed three-voltage (3VL) method. The TVM is in agreement with the Boutillon method and IonTracks for dose rates above 100 Gy min-1. However, the TVM calculated k s is closer related to the Jaffé theory for initial recombination for lower dose rate, indicating a limited application in scanning light ion beams. The 3VL is in turn found to generally be in agreement with Boutillon's method. The recombination is mapped as a function of the dose rate and proton energy at the two centres using the Boutillon formalism: The initial recombination parameter was found to be A = (0.10 0.01) V at DCPT and A = (0.22 ± 0.13) V at Skandion, which is in better agreement with the Jaffé theory for initial recombination than previously reported values. The general recombination parameter was estimated to. Furthermore, the numerical algorithm IonTracks is demonstrated to correctly predict the initial recombination at low dose rates and the general recombination at high dose rates.

Although the interaction of a flat-foil with currently available laser intensities is now considered a routine process, during the last decade emphasis is given to targets with complex geometries aiming on increasing the ion energy. This work presents a target geometry where two symmetric side-holes and a central-hole are drilled into the foil. A study of the various side-holes and central-hole length combinations is performed with 2-dimensional particle-in-cell simulations for polyethylene targets and a laser intensity of 5.2x10^21 W cm^-2. The holed-targets show a remarkable increase of the conversion efficiency, which corresponds to a different target configuration for electrons, protons and carbon ions. Furthermore, diffraction of the laser pulse leads to a directional high energy electron beam, with a temperature of ~40 MeV or seven times higher than in the case of a flat-foil. The higher conversion efficiency consequently leads to a significant enhancement of the maximum proton energy from holed-targets., 22 pages, 10 figures

Proton radiotherapy has clear dosimetric advantages over photon radiotherapy. In contrast to photons, which are absorbed exponentially, protons have a finite range dependent on the initial proton energy. Protons therefore do not deposit dose beyond the tumor, resulting in great conformality, and offers the promise of dose escalation to increase tumor control while minimizing toxicity. In this review, we discuss the rationale for using proton radiotherapy in the treatment of upper abdominal tumors—hepatocellular carcinomas, cholangiocarcinomas and pancreatic cancers. We also review the clinical outcomes and technical challenges of using proton radiotherapy for the treatment of these malignancies. Finally, we discuss the ongoing clinical trials implementing proton radiotherapy for the treatment of primary liver and pancreatic tumors.

The effect of low-dose proton irradiation (irradiation dose 1010–1.8 × 1011 cm–2) on the capacitance–voltage, forward current–voltage, and reverse-recovery characteristics of 4H-SiC p–no junction diodes is studied. Irradiation is performed with 1.8-MeV protons through a 10-μm-thick Ni-film (the proton energy and Ni-film thickness were chosen so that the projected proton range in silicon carbide is approximately equal to the p–no junction depth). It is shown that proton irradiation in the above doses (i) does not change the concentration of majority carriers, (ii) leads to a dramatic decrease in the lifetime of nonequilibrium carriers (at a low injection level) (by several tens of times at the highest irradiation dose), and (iii) decreases the reverse-recovery charge at a high injection level (by up to a factor of 3 at the highest irradiation dose).

We measured the excitation functions of natTa(p,x)177,178W, natTa(p,x)176,177,178m1,180gTa, and natTa(p,x)175,179m2,180mHf reactions up to the proton energy of 44.2 MeV using the stacked-foil activation technique. The measured results were compared with the literature data as well as with the theoretical values obtained from the TENDL-2017 library based on the TALYS-1.9 code. The integral yields for thick target of the investigated radionuclides were determined from the measured excitation functions. The purpose was to provide a new data set for the formation of the investigated radionuclides applicable in medicine and industry and to provide information that could support in testing and understanding the nuclear reaction theories.

We have started an experimental program to measure activation cross sections systematically in the proton-induced spallation reaction in structural materials commonly used in high-intensity proton ...

The effect of proton irradiation on the electrical characteristics of high-voltage (3 kV) 4H-SiC junction diodes is studied. The diodes are irradiated through a 10-μm-thick Ni mask. The proton energy and the irradiation dose are 2.8 MeV and 4 × 1011 cm–2, respectively. After irradiation, the forward differential resistance of the diodes increased by ~35%, the reverse-recovery charge decreased by a factor of ~3, and the nature of the reverse recovery became “hard.”

The Proton Power Upgrade (PPU) project is underway at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. The project will double the proton accelerator power from 1.4 MW to 2.8 MW, increase power to the First Target Station (FTS), and enable a future Second Target Station (STS). The power increase partly comes from raising proton energy from 1.0 GeV to 1.3 GeV. The STS will operate at 0.7 MW at 15 Hz when completed. Until then, PPU will provide the capability to operate the FTS at 2.0 MW at 60 Hz. Maximum power at the FTS to date has been 1.4 MW at 60 Hz with 1.0 GeV protons. A new mercury target module design to operate reliably under PPU conditions has been completed after a multi-year effort. The design philosophy and assessment of the structural analysis are described here. This target underwent an unprecedented design and analysis process for SNS using the latest engineering techniques and incorporating years of operating lessons and outcomes from R&D to meet structural design criteria. It also incorporates high-flow gas injection to further mitigate pulse fatigue stresses as well as cavitation damage to the mercury vessel.