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Abstract The twofold goals of this work are (i) to reduce the lack of experimental data in literature concerning the effects of temperature and mechanical strain on magnetic properties of the Ni-Fe alloy Cryophy, and (ii) to validate its use as magnetic shield material for last-generation cryomodule prototypes of crab cavities used in particle accelerators for transverse deflection. The relative magnetic permeability was measured at room and cryogenic temperature, and its lowest value at 4 K fits the minimum design criteria of 100,000 for the crab cavities experiment at CERN. Permeability after uniaxial plastic deformation between 0% and 3% was also measured by means of an Epstein frame. Results show that deformation induces a significant decrease in the magnetic performances, underlining that particular care must be taken during all stages of handling and operation. Finally, the attenuation inside the magnetic shields was tested for the prototype Super Proton Synchrotron at CERN. Results highlight that at 150 mm from the opening, the magnetic field is shielded as required. [ABSTRACT FROM AUTHOR]

Abstract Protons are transported from the mitochondrial matrix to the intermembrane space of mitochondria during the transfer of electrons to oxygen and shuttled back to the matrix by the a subunit and a ring of identical c subunits across the membrane domain (F O) of ATP synthase, which is coupled to ATP synthesis. A mutation (m.9176 T > G) of the mitochondrial ATP6 gene that replaces an universally conserved leucine residue into arginine at amino acid position 217 of human subunit a (a L 217 R) has been associated to NARP (Neuropathy, Ataxia and Retinitis Pigmentosa) and MILS (Maternally Inherited Leigh's Syndrome) diseases. We previously showed that an equivalent thereof in Saccharomyces cerevisiae (a L 237 R) severely impairs subunit a assembly/stability and decreases by >90% the rate of mitochondrial ATP synthesis. Herein we identified three spontaneous first-site intragenic suppressors (a R 237 M, a R 237 T and a R 237 S) that fully restore ATP synthase assembly. However, mitochondrial ATP synthesis rate was only partially recovered (40–50% vs wild type yeast). In light of recently described high-resolution yeast ATP synthase structures, the detrimental consequences of the a L 237 R change can be explained by steric and electrostatic hindrance with the universally conserved subunit a arginine residue (a R 176) that is essential to F O activity. a L 237 together with three other nearby hydrophobic residues have been proposed to prevent ion shortage between two physically separated hydrophilic pockets within the F O. Our results suggest that a L 237 favors subunit c -ring rotation by optimizing electrostatic interaction between a R 176 and an acidic residue in subunit c (c E 59) known to be essential also to the activity of F O. Highlights • Molecular basis of diseases induced by the m.9176 T > G mutation • Intragenic suppressors of the m.9176 T > G mutation in yeast • Role of the leucine residue at position 237 of yeast subunit a [ABSTRACT FROM AUTHOR]

Distributed optical fiber (OF) radiation sensing is a technique recently adopted at CERN for the monitoring of radiation dose levels in the proton synchrotron (PS) booster and in the PS. In this paper, we present the progress made on our previous work by benchmarking the rich information contained in the spatially distributed OF dose measurement with the radiation levels simulated with the FLUKA Monte Carlo code. We begin by discussing the experimental results for the qualification/calibration of a new radiation sensitive single-mode OF, currently being deployed in the accelerator tunnels. We performed this calibration tests online under 60Co $\gamma $ -rays source. We then move on to report the results of the online irradiation tests that we carried out in the CERN high energy accelerator mixed-field facility. Finally, we compare the OF radiation maps with the dose levels calculated along the OF cable with FLUKA for two very different configurations of the facility. This paper is a first promising example of combining 3-D Monte Carlo simulations of complex mixed-field environment with the 1-D spatially distributed dose measurements provided by the OF-based dosimetry. [ABSTRACT FROM AUTHOR]

The yields of cumulative protons and π± mesons emitted at a laboratory angle of 40° from carbon and heavier nuclear targets irradiated by a proton beam from the U70 accelerator (Institute for High Energy Physics, Protvino) have been studied in the SPIN experiment. It has been found that the effect of the target nucleus on the yield of particles with large transverse momenta is weakened. [ABSTRACT FROM AUTHOR]

Abstract This paper proposes a novel input power control strategy for high-power dynamic power supply for proton therapy. A buck chopper is staged in series between the input rectifier and the output chopper of the power supply to buffer the input power fluctuation, which can reduce the reactive power exchange between the power supply and power grid and reduce the power distribution requirements. The validity of this proposed control principle has been verified on a high-power dynamic dipole power supply for proton therapy. [ABSTRACT FROM AUTHOR]

At CERN, large hadron collider heavy ion and super proton synchrotron fixed target experiments are performed thanks to the Heavy-ion Facility, composed of different accelerators. The starting point is Linac3, which delivers 4.2 MeV/u ion beams to the low energy ion ring. In 2017, Linac3 accelerated Xe instead of the most usual Pb. This article summarizes the measurements performed during the machine development time allocated to characterize the line from the source to the filtering section. A parallel effort was devoted to matching those measurements to the beam dynamics simulations, and the second part of the article highlights the results achieved in this regard. Thanks to the improved understanding of the machine critical areas, a list of possible improvements is proposed at the end. [ABSTRACT FROM AUTHOR]

Abstract A method to characterise the quality of a fused silica surface using a β -source is presented. Two fused silica bars (5 × 10 × 400 mm 3) were fabricated for the Cherenkov detector for proton Flux Measurement installed at vacuum chamber of the Super Proton Synchrotron at CERN. The resolution of such device is defined by the collection efficiency of the Cherenkov light, which is produced by relativistic charged particles in the fused silica. Thus, the surface quality of the radiator should be as good as possible to avoid light losses. The method is based on the scanning of the radiator surface with a 90 S r radioactive source and measurements of the Cherenkov light rate, detected by a PMT attached to the quartz bars. The data have been compared with a Monte-Carlo simulation, providing an estimation of the radiator's probability of the total internal reflection and inefficient area at the edges of the bars. [ABSTRACT FROM AUTHOR]

Abstract The CERN High-Energy AcceleRator Mixed field (CHARM) facility provides a secondary particle field, produced by irradiating a thick target with 24 GeV/c protons supplied by the proton synchrotron. In order to investigate the thermalization process of secondary neutrons in the CHARM facility, we measured the thermal neutrons using the gold foil activation method. Bare and Cd-covered gold foils were placed at 35 positions to deduce the thermal neutron distribution in the CHARM facility. The 197Au(n, γ)198Au reaction rates and thermal neutron fluxes measured in this study were compared with the Monte Carlo simulation codes, PHITS, FLUKA, and MARS. The comparison between the measured and simulated values gives an agreement better than a factor of two. Besides, we investigated the simple empirical formula to estimate a thermal neutron flux in the accelerator room, ϕ th = CQ / S , where Q is the neutron source intensity and S is the total surface area of a room. The coefficient C estimated in this study did not significantly depend on the incident proton beam energy. [ABSTRACT FROM AUTHOR]

The main ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC) is a high-intensity proton synchrotron that supplies proton beams for the long-baseline neutrino experiment, called the Tokai to Kamioka (T2K). To satisfy the experimental condition for the T2K, the increase in the present beam power of 450 kW to 750 kW and beyond is mandatory. The scheme of the high-repetition-rate operation is adopted for the MR upgrade. The repetition cycle is planned to be shortened from 2.48 s at present to 1.28 s in this scheme. This upgrade involves the increase in the power variation of the electrical system. To suppress the power variation, an energy storage that consists of capacitor banks (CBs) was developed and installed in the power supply of the main magnets, since the main magnets are the primary source of power variation. The CB was designed with a sufficient consideration to avoid serious failures. The number of fuses were installed in the CB to avoid energy concentration on a short-circuited capacitor. The scheme for the safe dissipation of the concentrated energy was also employed. A fuse arcing test was carried out to clearly show the fuse reliability since the CB safety is strongly dependent upon the fuses. [ABSTRACT FROM AUTHOR]

The CERN Super Proton Synchrotron (SPS) has delivered a variety of beams to a vigorous fixed target physics program since 1978. In this paper, we restrict ourselves to the description of a few illustrative examples in the ongoing physics program at the SPS. We will outline the physics aims of the COmmon Muon Proton Apparatus for Structure and Spectroscopy (COMPASS), north area 64 (NA64), north area 62 (NA62), north area 61 (NA61), and advanced proton driven plasma wakefield acceleration experiment (AWAKE). COMPASS studies the structure of the proton and more specifically of its spin. NA64 searches for the dark photon A’, which is the messenger for interactions between normal and dark matter. The NA62 experiment aims at a 10% precision measurement of the very rare decay K+ → π+νν. As this decay mode can be calculated very precisely in the Standard Model, it offers a very good opportunity to look for new physics beyond the Standard Model. The NA61/SHINE experiment studies the phase transition to Quark Gluon Plasma, a state in which the quarks and gluons that form the proton and the neutron are de-confined. Finally, AWAKE investigates proton-driven wake field acceleration: a promising technique to accelerate electrons with very high accelerating gradients. The Physics Beyond Colliders study at CERN is paving the way for a significant and diversified continuation of this already rich and compelling physics program that is complementary to the one at the big colliders like the Large Hadron Collider. [ABSTRACT FROM AUTHOR]

The CERN large hadron collider (LHC) InjectorsUpgrade seeks to reliably deliver the beams required for the High- Luminosity LHC (HL-LHC). As part of this, the proton synchrotron booster (PSB) will be upgraded from1.4 to 2GeV andwill accelerate higher intensity beams. Along the transfer lines between the PSB and the proton synchrotron there are several dc-operated quadrupole magnets that are unable to produce the gradients required for the 2 GeV HL-LHC beams. To minimize power consumption, these will be replaced by laminated quadrupole magnets, operated in pulse to pulse modulation mode. The field homogeneity requirements imposed on these magnets is very tight, requiring a homogeneity of 5 × 10-4 on the integrated gradient. Such strict requirements presented several issues for the design, especially when considering the space constraints that naturally apply when upgrading a pre-existing accelerator. The design of these quadrupole magnets is summarized here. [ABSTRACT FROM AUTHOR]

Some therapeutic proton synchrotron accelerators will be built for cancer treatment in China. The radiation produced by proton must be carefully evaluated and shielded for occupational disease hazard assessment and environmental impact assessment. Adopting the FLUKA code, a therapeutic room model, a synchrotron hall model and a high energy transport line tunnel model are constructed to get the ambient dose equivalent rate distributions. The ambient dose equivalent rates are also calculated with an empirical formula in some regions. The results calculated by the two ways are consistent with each other. The advantages and disadvantages of the two methods have been analyzed. The ambient dose equivalent rates are no more than 2.5 μSv/h at 30 cm beyond the shielding wall and the maze door. The dose rates are <25 μSv/h at 30 cm beyond the roof of the therapeutic room. These results comply with the National Occupational Health Standard requirements. [ABSTRACT FROM AUTHOR]

Based on the coalescence model for light nuclei production, we show that the yield ratio O p-d-t = N H 3 N p / N d 2 of p , d, and 3 H in heavy-ion collisions is sensitive to the neutron relative density fluctuation Δ n = 〈 ( δ n ) 2 〉 / 〈 n 〉 2 at kinetic freeze-out. From recent experimental data in central Pb + Pb collisions at s N N = 6.3 GeV , 7.6 GeV , 8.8 GeV , 12.3 GeV and 17.3 GeV measured by the NA49 Collaboration at the CERN Super Proton Synchrotron (SPS), we find a possible non-monotonic behavior of Δ n as a function of the collision energy with a peak at s N N = 8.8 GeV , indicating that the density fluctuations become the largest in collisions at this energy. With the known chemical freeze-out conditions determined from the statistical model fit to experimental data, we obtain a chemical freeze-out temperature of ∼ 144 MeV and baryon chemical potential of ∼ 385 MeV at this collision energy, which are close to the critical endpoint in the QCD phase diagram predicted by various theoretical studies. Our results thus suggest the potential usefulness of the yield ratio of light nuclei in relativistic heavy-ion collisions as a direct probe of the large density fluctuations associated with the QCD critical phenomena. [ABSTRACT FROM AUTHOR]

J-PARC is a Japanese proton synchrotron accelerator facility, and is under consideration of an upgrade for accelerating heavy ions. A beam rate of about 10 11 Hz is expected with the upgraded accelerator scheme, with which the QCD phase structure, hadrons under a high baryon density, and multi-strange hypernuclei can be studied. In this paper, we discuss the plan for the upgrade and the conceptual design of the detectors for several physics cases. [ABSTRACT FROM AUTHOR]

Recent data on the deutron and He production in central Pb+Pb collisions at the CERN Super Proton Synchrotron (SPS) energies measured by the NA49 Collaboration are analyzed within the model of the three-fluid dynamics (3FD) complemented by the coalescence model for the light-fragment production. The simulations are performed with different equations of state --with and without deconfinement transition. It is found that scenarios with the deconfinement transition are preferable for reproduction rapidity distributions of deuterons and He, the corresponding results well agree with the experimental data. At the same time the calculated transverse-mass spectra at midrapidity do not agree that nicely with the experimental data. The latter apparently indicate that coalescence coefficients should be temperature and/or momentum dependent. [ABSTRACT FROM AUTHOR]

Measurements of inclusive spectra and mean multiplicities of $$\pi ^\pm $$ , K $$^\pm $$ , p and $${\bar{\text {p}}}$$ produced in inelastic p + p interactions at incident projectile momenta of 20, 31, 40, 80 and 158 $$\text{ GeV }/c$$ ( $$\sqrt{s} = $$ 6.3, 7.7, 8.8, 12.3 and 17.3 $$\text{ GeV }$$ , respectively) were performed at the CERN Super Proton Synchrotron using the large acceptance NA61/SHINE hadron spectrometer. Spectra are presented as function of rapidity and transverse momentum and are compared to predictions of current models. The measurements serve as the baseline in the NA61/SHINE study of the properties of the onset of deconfinement and search for the critical point of strongly interacting matter. [ABSTRACT FROM AUTHOR]

Water molecules can serve as proton shuttles for proton transfer in the C-H bond insertion reactions catalyzed by transition metal complexes. Recently, the control experiments performed for C-H bond insertion of phenol and anisol by gold carbenes show that large discrepancy exists in the yields of hydrogenated and deuterated products. Thus, we conducted a detailed theoretical analysis on the function of water molecules in the C-H bond insertion reactions. The comparison of calculated results and control experiments indicates that the solution water molecules play a crucial role of proton shuttle in C-H bond insertion. In particular, it was found that the hydroxyl groups in phenols were capable of donating protons via water shuttles for the production of C-H products, which had a substantial influence on the yields of inserted products. The hydroxyl groups instead of C-H bonds in phenols function like "proton reservoirs" in the C-H bond insertion, which we call the "proton self-sufficient" (PSS) function of phenol. The PSS function of phenol indicates that the substrates with and without proton reservoirs will lead to different C-H bond insertion products. [ABSTRACT FROM AUTHOR]

Solvation and transport of excess protons in aqueous systems play a fundamental role in acid-base chemistry and biochemical processes. We mapped ultrafast proton excursions along the proton transfer coordinate by means of two-dimensional infrared spectroscopy, both in bulk water and in a Zundel cation (H5O2)+ motif selectively prepared in acetonitrile. Electric fields from the environment and stochastic hydrogen bond motions induce fluctuations of the proton double-minimum potential. Within the lifetime of a particular hydration geometry, the proton explores a multitude of positions on a sub-100-femtosecond time scale. The proton transfer vibration is strongly damped by its 20- to 40-femtosecond population decay. Our results suggest a central role of Zundel-like geometries in aqueous proton solvation and transport. [ABSTRACT FROM AUTHOR]

Selective refocusing (GSERF or the recent PSYCHEDELIC) experiments were originally designed to determine all proton-proton coupling constants ( JHH) for a selected proton resonance. They work for isolated signals on which selective excitation can be successfully applied but, as it happens in other selective experiments, fail for overlapped signals. To circumvent this limitation, a doubly-selective TOCSY-GSERF scheme is presented for the measurement of JHH in protons resonating in crowded regions. This new experiment takes advantage of the editing features of an initial TOCSY transfer to uncover hidden resonances that become accessible to perform the subsequent frequency-selective refocusing. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The flat spectrum radio quasar 3C 279 is a known γ-ray variable source that has recently exhibited minute-scale variability at energies > 100 MeV. One-zone leptonic models for blazar emission are severely constrained by the short time-scale variability that implies a very compact emission region at a distance of hundreds of Schwarzschild radii from the central black hole. Here, we investigate a hadronic scenario where GeV γ-rays are produced via proton synchrotron radiation. We also take into account the effects of the hadronically initiated electromagnetic cascades (EMC). For a γ-ray emitting region in rough equipartition between particles and kG magnetic fields, located within the broad-line region (BLR), the development of EMC redistributes the γ-ray luminosity to softer energy bands and eventually leads to broadband spectra that differ from the observed ones. Suppression of EMC and energy equipartition are still possible, if the γ-ray emitting region is located beyond the BLR, is fast moving with Doppler factor (>70) and contains strong magnetic fields (>100 G). Yet, these conditions cannot be easily met in parsec-scale jets, thus disfavouring a proton synchrotron origin of the Fermi-LAT flare. [ABSTRACT FROM AUTHOR]

The NA62 experiment is designed to measure the (ultra-)rare decay K + → π + ν ν ¯ branching ratio with a precision of ∼ 10 % at the CERN Super Proton Synchrotron (SPS). The L0 Trigger Processor (L0TP) is the lowest level system of the trigger chain. It is hardware implemented using programmable logic. The architecture of the L0TP is completely new for a high energy physics experiment. It is fully digital, based on a standard gigabit ethernet communication between detectors and L0TP Board. The L0TP Board is a commercial development board, Terasic DE4, mounting an Altera Stratix IV FPGA. The primitives generated by sub-detectors are sent asynchronously using the UDP protocol to the L0TP during the entire beam spill period (about 5 seconds). The L0TP realigns in time the primitives coming from 7 different sources and manages the information of the time plus all the characteristics of the event as energy, multiplicity and position of hits in order to select good events with a comparison with preset masks. It should guarantee a maximum latency of 1 ms. The maximum input rate is 10 MHz for each sub-detector, while the design maximum output trigger rate is 1 MHz. A complete trigger-less parasitic acquisition of the primitives is possible using mirroring switches to monitor the L0 behavior. A first version of the L0TP was commissioned during the 2014 NA62 pilot run and it is used in the current data taking. A description of the trigger algorithm is here presented. [ABSTRACT FROM AUTHOR]

J-PARC Main Ring (MR) is a high intensity proton synchrotron which accelerates protons from 3 GeV to 30 GeV. It has operated at a beam intensity of 390 kW and an upgrade toward the megawatt rating is scheduled. For higher beam intensity, some of the accelerator components require more intelligent and complicated functions. To consolidate such functions among various components, we developed multi-purpose digital boards using a System-on-Chip Field-Programmable Gated Array (SoC FPGA). In this paper, we describe the details of our developed boards as well as their possible applications. As an application of the boards, we have successfully performed the measurement of the betatron amplitude function during beam acceleration in J-PARC MR. The experimental setup and results of the measurement are also described in detail. [ABSTRACT FROM AUTHOR]

Predictions on fluctuations of hadron production properties in central heavy-ion collisions are presented. They are based on the Statistical Model of the Early Stage and extend previously published results by considering the strongly intensive measures of fluctuations. In several of the considered cases, a significant change in collision-energy dependence of calculated quantities as a result of the phase transition is predicted. This provides an opportunity to observe new signals of the onset of deconfinement in heavy-ion collisions experiments. [ABSTRACT FROM AUTHOR]

Several supernovae (SNe) with an unusually dense circumstellar medium (CSM) have been recently observed at radio frequencies. Their radio emission is powered by relativistic electrons that can be either accelerated at the SN shock (primaries) or injected as a by-product (secondaries) of inelastic proton-proton collisions. We investigate the radio signatures from secondary electrons, by detailing a semi-analytical model to calculate the temporal evolution of the distributions of protons, primary and secondary electrons. With our formalism, we track the cooling history of all the particles that have been injected into the emission region up to a given time, and calculate the resulting radio spectra and light curves. For an SN shock propagating through the progenitor wind, we find that secondary electrons control the early radio signatures, but their contribution decays faster than that of primary electrons. This results in a flattening of the light curve at a given radio frequency that depends only upon the radial profiles of the CSM density and of the shock velocity, υ0. The relevant transition time at the peak frequency is ∼190 d K-1ep,-3 Aw,16/β20,-1.5, where Aw is the wind mass-loading parameter, β0 = υ0/c and Kep are the electron-to-proton ratio of accelerated particles. We explicitly show that late peak times at 5 GHz (i.e. tpk ≳ 300-1000 d) suggest a shock wave propagating in a dense wind (Aw ≳ 1016-1017 gr cm-1), where secondary electrons are likely to power the observed peak emission. [ABSTRACT FROM AUTHOR]

A method for analyzing the transverse beam feedback circuit in a ring accelerator and selecting its parameters using the concept of the active beam coupling impedance, which is externally imposed and controlled, is described. This approach is used for the physical substantiation of approaches to upgrading two operational transverse feedback systems that are available in the U-70 synchrotron of the Institute for High Energy Physics, National Research Centre Kurchatov Institute: narrow-band analog and broadband digital systems. Both systems were subjected to deep upgrading, which is based on this method, and were successfully commissioned in 2007 and 2011, respectively. A brief description of their updated engineering implementation is given. The presented experimental results confirm the adequacy of the impedance approach to designing and adjusting the transverse beam feedback circuits in the U-70 synchrotron. [ABSTRACT FROM AUTHOR]

We study pion production by proton synchrotron radiation in the presence of a strong magnetic field when the Landau numbers of the initial and final protons are n i , f ∼ 10 4 – 10 5 . We find in our relativistic field theory calculations that the pion decay width depends only on the field strength parameter which previously was only conjectured based upon semi-classical arguments. Moreover, we also find new results that the decay width satisfies a robust scaling relation, and that the polar angular distribution of emitted pion momenta is very narrow and can be easily obtained. This scaling implies that one can infer the decay width in more realistic magnetic fields of 10 15 G , where n i , f ∼ 10 12 – 10 13 , from the results for n i , f ∼ 10 4 – 10 5 . The resultant pion intensity and angular distributions for realistic magnetic field strengths are presented and their physical implications discussed. [ABSTRACT FROM AUTHOR]

Experimental results of the rapidity distributions of negatively charged pions produced in proton-proton (p-p) and beryllium-beryllium (Be-Be) collisions at different beam momentums, measured by the NA61/SHINE Collaboration at the super proton synchrotron (SPS), are described by a revised (three-source) Landau hydrodynamic model. The squared speed-of-sound parameter cs2 is then extracted from the width of rapidity distribution. There is a local minimum (knee point) which indicates a softest point in the equation of state (EoS) appearing at about 40A GeV/c (or 8.8 GeV) in cs2 excitation function (the dependence of cs2 on incident beam momentum (or center-of-mass energy)). This knee point should be related to the searching for the onset of quark deconfinement and the critical point of quark-gluon plasma (QGP) phase transition. [ABSTRACT FROM AUTHOR]

A novel system for high-energy beam extraction from the U-70 proton synchrotron to the external beam transfer line (i.e., a multiturn fast extraction system) is described. The beam is forced into the first upstream ejection device-an electrostatic deflector-by means of fast dipole bump magnets with the field rise time of 50-100 μs (equivalent of 10-20 beam turns). The fast bump magnets and their power supplies are described. The first experimental results acquired during trial operation of the multiturn fast extraction system in 2014 are presented. From these results, it is apparent that the extracted beam parameters are close to those obtained with the available single-turn fast extraction system. [ABSTRACT FROM AUTHOR]

History, status and plans of the search for critical behaviour of strongly interacting matter created in nucleus-nucleus collisions at the CERN Super Proton Synchrotron is reviewed. In particular, it is expected that the search should answer the question whether the critical point of strongly interacting matter exists and, if it does, where it is located. First, the search strategies are presented and a short introduction is given to expected fluctuation signals and to the quantities used by experiments to detect them. The most important background effects are also discussed. Second, relevant experimental results are summarized and discussed. It is intriguing that both the fluctuations of quantities integrated over the full experimental acceptance (event multiplicity and transverse momentum) as well as the bin size dependence of the second factorial moment of pion and proton multiplicities in medium-sized Si+Si collisions at 158A GeV/c suggest critical behaviour of the created matter. These results provide strong motivation for the ongoing systematic scan of the phase diagram by the NA61/SHINE experiment at the SPS and the continuing search at the Brookhaven Relativistic Hadron Collider. [ABSTRACT FROM AUTHOR]

Ion acceleration due to the interaction between a short high-intensity laser pulse and a moderately overdense plasma target is studied using Eulerian Vlasov-Maxwell simulations. The effects of variations in the plasma density profile and laser pulse parameters are investigated, and the interplay of collisionless shock and target normal sheath acceleration is analyzed. It is shown that the use of a layered-target with a combination of light and heavy ions, on the front and rear side, respectively, yields a strong quasi-static sheath-field on the rear side of the heavy-ion part of the target. This sheath-field increases the energy of the shock-accelerated ions while preserving their mono-energeticity. [ABSTRACT FROM AUTHOR]

In some circumstances passive detecting methods are the only or preferable measuring approaches. For instance, defining particles׳ energy profile inside the objects being irradiated with heavy ions and measuring fluence of neutrons or heavy particles in space missions are the cases covered by these methods. In this paper the ability of polyallyl diglycol carbonate (PADC) track detector (commercially known as CR-39) for passive spectrometry of proton particles is studied. Furthermore, the effect of KOH and NaOH as commonly used chemical etching solutions on the response of the detector is investigated. The experiments were carried out with protons in the energy range of 0.94–2.5 MeV generated by a Van de Graaff accelerator. Then, the exposed track dosimeters were etched in the two aforementioned etchants through similar procedure with the same normality of 6.25 N and the same temperature of 85 °C. Formation of the tracks was precisely investigated and the track diameters were recorded following every etching step for each solution using a multistage etching process. The results showed that the proposed method can be efficiently used for the spectrometry of protons over a wider dynamic range and with a reasonable accuracy. Moreover, NaOH and KOH outperformed each other over different regions of the proton energy range. The detection efficiency of both etchants was approximately 100%. [ABSTRACT FROM AUTHOR]

Purpose: Proton computed tomography (pCT) will enable accurate prediction of proton and ion range in a patient while providing the benefit of lower radiation exposure than in x-ray CT. The accuracy of the range prediction is essential for treatment planning in proton or ion therapy and depends upon the detector used to evaluate the water-equivalent path length (WEPL) of a proton passing through the object. A novel approach is presented for an inexpensive WEPL detector for pCT and proton radiography. Methods: A novel multistage detector with an aperture of 10?Ñ37.5 cm was designed to optimize the accuracy of the WEPL measurements while simplifying detector construction and the performance requirements of its components. The design of the five-stage detector was optimized through simulations based on the GEANT4 detector simulation toolkit, and the fabricated prototype was calibrated in water-equivalent millimeters with 200 MeV protons in the research beam line of the clinical proton synchrotron at Loma Linda University Medical Center. A special polystyrene step phantom was designed and built to speed up and simplify the calibration procedure. The calibrated five-stage detector was tested in the 200 MeV proton beam as part of the pCT head scanner, using a water phantom and polystyrene slabs to verify the WEPL reconstruction accuracy. Results: The beam-test results demonstrated excellent performance of the new detector, in good agreement with the simulation results. The WEPL measurement accuracy is about 3.0 mm per proton in the 0-260 mm WEPL range required for a pCT head scan with a 200 MeV proton beam. Conclusions: The new multistage design approach to WEPL measurements for proton CT and radiography has been prototyped and tested. The test results show that the design is competitive with much more expensive calorimeter and range-counter designs. [ABSTRACT FROM AUTHOR]

The use of conventional Bonner Sphere Spectrometers (BSS) in pulsed neutron fields (PNF) is limited by the fact that proportional counters, usually employed as the thermal neutron detectors, suffer from dead time losses and show severe underestimation of the neutron interaction rate, which leads to strong distortion of the calculated spectrum. In order to avoid these limitations, an innovative BSS, called BSS-LUPIN, has been developed for measuring in PNF. This paper describes the physical characteristics of the device and its working principle, together with the results of Monte Carlo simulations of its response matrix. The BSSLUPIN has been tested in the stray neutron field at the CERN Proton Synchrotron, by comparing the spectra obtained with the new device, the conventional CERN BSS and via Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

This work develops a theoretical-experimental procedure for production of Re radionuclide at low energy cyclotrons. TALYS code with different level density models is used to calculate the excitation function of W(p,x)Re reaction up to 30 MeV incident energy. To prepare the target, the natural tungsten is deposited on a copper substrate via sedimentation technique. The target is irradiated by 15 MeV protons at 20 μA beam current for 1 h. Re is radiochemically separated from tungsten contaminations and its production yield is measured. In parallel to the experiment, a Monte Carlo method is appended to simulate the irradiation process. [ABSTRACT FROM AUTHOR]

A prototype for a sampling calorimeter made out of cerium fluoride crystals interleaved with tungsten plates, and read out by wavelength-shifting fibres, has been exposed to beams of electrons with energies between 20 and 150 GeV, produced by the CERN Super Proton Synchrotron accelerator complex. The performance of the prototype is presented and compared to that of a Geant4 simulation of the apparatus. Particular emphasis is given to the response uniformity across the channel front face, and to the prototype׳s energy resolution. [ABSTRACT FROM AUTHOR]