Search

Simulation of 5 MeV-proton irradiation of different construction steels for nuclear installations was performed using the MCNPX code to support proton irradiation experiments aimed at studying accelerated radiation aging. The main goal of the simulations was to predict an induced activity of the studied samples during implantation experiments. The materials investigated were different types of Fe-Cr-based construction steels comprising ferritic/martensitic steels and its oxide dispersion strengthened variant. The paper presents calculation details specific for a couple of MeV-protons simulations comprising the information on the proton nuclear data and the physics models' usage in the MCNPX code. The reaction rates and the energy deposition were calculated to quantify the main interaction mechanisms, whereby the capability of the MCNPX code to track the secondary particles was used. Physics models were employed to determine the nuclides inventory produced during irradiation. The induced mass activity was calculated from the number of radioactive residuals and reached values between 15 and 67 kBq/g immediately after irradiation. The results from simulations will be compared with the activity of the samples determined by gamma spectroscopy measurements in our next paper. [ABSTRACT FROM AUTHOR]

The study of neutrinoless double beta decay (DBD) has attracted much attention because it can provide valuable information about the mass and the nature of the neutrino. DBD itself is also of interest in nuclear physics. While DBD has been observed in about a dozen nuclei, the positron DBD (β+β+/EC-β +) continues to be elusive. An important signature for β +β + decay is the simultaneous emission of four 511 keV gamma rays, and the coincident detection of these gamma rays can improve the measurement sensitivity. This paper presents an estimation of sensitivity for EC-β+and β +β+, employing coincidence measurement with two high-purity Ge (HPGe) detectors. Simulations for coincident detection efficiency (εc) of 511 keV gamma rays with two HPGe detectors were carried out using GEANT4 for different source geometries to optimize the mass efficiency product (Mεc). A source of size 55 mm × 55 mm × 5 mm (thickness) sandwiched between the front faces of the detectors was found to be optimal for two pairs of 511 keV gamma rays in the present detector setup. The coincident background was estimated at sea level with moderate lead shielding. With this setup, the sensitivity for T1/2 measurement of EC-β+in 112Sn and β +β+ in 106Cd was estimated to be ∼1019–1020 years for one year of measurement time. [ABSTRACT FROM AUTHOR]

The design of programming interfaces like ROOT written by CERN group in Switzerland leads the way of analyzing spectroscopy mainly in nuclear physics applications. One of the topics is a signal processing in terms of currency, voltage or frequency of a radiation hitting the detector systems. Mathematical approaches finding the fit parameters in maximum Likelihood for the normal distribution and the effect of choosing the distinct methods in fitting settings will be presented in this paper. [ABSTRACT FROM AUTHOR]

A next generation heavy ion accelerator complex HIAF (High Intensity heavy ion Accelerator Facility) was proposed by IMP and officially approved for nuclear physics and high energy density physics research. HIAF requests ion source that is able to deliver 50 pμA of 238U35+ pulsed beam and 25 pμA of 238U35+ CW beam for injector of a superconducting heavy ion linac. In order to meet the beam intensity requirements of highly charged heavy ions, a 45 GHz superconducting ECR ion source FECR (a Fourth generation ECR ion source) is under intense R&D at IMP. The effective power absorption form the microwaves to the plasma is key issue for increasing the beam intensity. Therefore, we introduced a 45 GHz gyrotron system which is capable for providing output power up to 20 kW in both CW and pulse modes as a microwave power source for FECR. Other than the gyrotron oscillator, the microwave power transmission coupling and ECR heating are critical issues for FECR. Since the wavelength of 45 GHz microwave is about 6.67 mm and the maximum power level is 20 kW, the quasi-optical transmission scheme is utilized for high power transmission. The technical details of transmission line and coupling system will be presented in this paper. After off-line tests of microwave transmission efficiency and mode purity, 45 GHz gyrotron microwave source will be commissioned with SECRAL II (a superconducting ECR ion source optimized for 28 GHz operation), and some preliminary results of ECR heating and intense beam production will be discussed in this paper. [ABSTRACT FROM AUTHOR]

The manganese bath activation technique has been developed and actively used for neutron emission rate measurements at the laboratory of the Institute of Nuclear and Physical Engineering FEI STU since 2015. For this technique a spherical Plexiglas vessel with manganese sulfate solution and Pu-Be isotope neutron source is used, which is before and after the emission rate measurement transported using a special source loading mechanism. Since all activities involved in the work with sources of radiation must be in line with the ALARA (As Low As Reasonably Achievable) principle, it is necessary to estimate the radiation situation during the source loading procedure and to optimize the measurement process. This paper focuses on the simulation of the radiation situation in case of these transportation process, based on Monte Carlo simulation using the detailed model of the experimental workspace developed in the SCALE6 system. The model consists of geometry configurations that can influence the attenuation of gamma and neutron radiation. To estimate the radiation situation 3D neutron and gamma mesh tallies and 5 point detectors, placed at specific positions, are used. The paper includes the achieved results of the dose rates as well as discussion on the optimization of the measurement process. [ABSTRACT FROM AUTHOR]

Circularly polarized photons are widely used for conducting experiments to study magnetic structures of matter. On the basis of superconducting coils developed at Budker Institute of Nuclear Physics for a short-period superconducting planar undulator, a superconducting elliptical undulator with a period of ∼2.2 cm and an elliptic coefficient of∼0.7 is proposed. The poles of the upper and lower halves of the undulator are located at an angle of 45 degrees to each other in the horizontal plane, which creates periodic vertical and horizontal elliptical fields of up to 1 T vertically and 0.7 T horizontally. Fast switching of the electron orbit using correction magnets external to the cryostat (up to hundreds of Hz) enables fast switching of the left and right polarizations of the zero-angle radiation from two sequentially installed undulators. A short prototype of elliptical superconducting undulator was fabricated and magnetic measurements were made in a bath cryostat. The paper presents numerical calculations of the undulator fields, spectra, and experimentally measured field. [ABSTRACT FROM AUTHOR]

Circularly polarized photons are widely used for conducting experiments to study magnetic structures of matter. Based on coils developed at Budker Institute of Nuclear Physics (BINP) for a superconducting undulator with a period of 15.6 mm, a model of a superconducting undulator with variable polarization (SCUVP) and a period of 40 mm is proposed. SCUVP consists of two identical superconducting undulators placed mutually perpendicular and powered by currents independently. Depending on different current values in the windings of the undulator, it is possible to create an elliptical undulator with different elliptic coefficients or planar undulators with linear radiation polarization with a zero angle both horizontally and vertically. The paper presents numerical calculations of the undulator fields and its spectra. [ABSTRACT FROM AUTHOR]

A new normal-conducting, CW, thermocathode RF gun has been developed and tested recently at Budker Institute of Nuclear Physics. Providing an average current of up to 100 mA, this device will be used to upgrade the injector of the Novosibirsk FEL facility. Simulation of beam dynamics in the RF gun and its beamline was performed, the space-charge forces taken into account. Comparison of the simulation results and experimental measurements is presented in this paper. [ABSTRACT FROM AUTHOR]

The elastic scattering process Λp → Λp offers insights on multiple problems in nuclear physics. SU(3)F symmetry implies a close agreement between the Λp and pp scattering cross sections. The Λp elastic scattering cross section can also illuminate the structure of neutron stars. A data-mining project was started using multiple CLAS data sets taken for other purposes with photon beams on a long liquid hydrogen target. A Λ produced in a process such as γp → K+ Λ can interact with a second proton inside the target before either decaying or leaving the target. The good angular acceptance and momentum resolution of CLAS make it well-suited for this type of analysis, even though it was not designed for such a measurement. The scattered Λ can be identified from the π− p invariant mass. The four-vector of the initial Λ is then reconstructed in the process Xp → Λp, which shows a strong peak at the Λ mass with roughly twice the number of events as the existing world data sample. This observation opens up the possibility of other measurements using secondary beams of short-lived particles. This paper will discuss the current status of the analysis, and our plans for future work on this project. [ABSTRACT FROM AUTHOR]

Gravitational waves from neutron-star mergers are expected to provide stringent constraints on the structure of neutron stars. At the same time, recent advances in nuclear theory have enabled reliable calculations of the low density equation of state using effective field theory based Hamiltonians and advanced techniques to solve the quantum many-body problem. In this paper, we address how the first observation of gravitational waves from GW170817 can be combined with modern calculations of the equation of state to extract useful insights about the equation of state of matter encountered inside neutron stars. We analyze the impact of various uncertainties and we show that the tidal deformability extracted from GW170817 is compatible, while less constraining, than modern nuclear physics knowledge. [ABSTRACT FROM AUTHOR]

This paper presents an update on women and physics in Italy over the past five years. The numbers of women with physics degrees and the statistics on women with careers in universities or in the main Italian research institutions (National Institute for Nuclear Physics, National Institute of Astrophysics, and National Research Council) are given. Also, results are reported from European projects, such as Transforming Organisational Culture for Gender Equality in Research and Innovation and Gender Equality Network in the European Research Area in which Italy is involved. [ABSTRACT FROM AUTHOR]

The National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) is a user facility for rare-isotope beams, produced by projectile fragmentation at high energies and separated in-flight. ReA is a post-accelerator that accelerates 'stopped' rare-isotope beams, thermalized in a helium-gas cell, to several MeV/u for nuclear-physics experiments. ReA employs an electron-beam ion trap (EBIT) charge breeder to convert singly charged ions to highly charged ions before transport to a linear accelerator. The EBIT started on-line operation in the fall of 2015. This paper presents results of charge-breeding efficiency measurements obtained over the past two years with rare-isotope beams. Additionally, the time spread of rare-isotope ion pulses ejected from the EBIT has been increased to reduce the instantaneous rate delivered to users. Efficiencies in single charge states of more than 20% were obtained with 47K17+ and 34Ar15+. For 34Ar15+, the pulse width was spread in time up to ~50 ms. [ABSTRACT FROM AUTHOR]

To assess the ability of the SCALE system and the associated nuclear data to predict the VVER-440 spent fuel nuclide composition, the measured compositions of Novovoronezh NPP irradiated fuel assembly are compared to data calculated by TRITON sequence. The samples of fuel assembly with 3.6 wt. % 235U enrichment underwent 4-cycle campaign of totally 1109 days in the core and cooling period of 1-13 years. The simplified benchmark specification is based on operational history calculated by the Russian operational codes. Calculated concentrations are compared to measured values burdened with their experimental uncertainties for totally 47 nuclides. Calculated results show overall a good agreement for all nuclides, differences from measured are pointed out and discussed in the paper. [ABSTRACT FROM AUTHOR]

This paper introduces recent improvements for reactor physics codes in Mitsubishi Heavy Industries, Ltd(MHI). MHI has developed a new neutronics design code system Galaxy/Cosmo-S(GCS) for PWR core analysis. After TEPCO's Fukushima Daiichi accident, it is required to consider design extended condition which has not been covered explicitly by the former safety licensing analyses. Under these circumstances, MHI made some improvements for GCS code system. A new resonance calculation model of lattice physics code and homogeneous cross section representative model for core simulator have been developed to apply more wide range core conditions corresponding to severe accident status such like anticipated transient without scram (ATWS) analysis and criticality evaluation of driedup spent fuel pit. As a result of these improvements, GCS code system has very wide calculation applicability with good accuracy for any core conditions as far as fuel is not damaged. In this paper, the outline of GCS code system is described briefly and recent relevant development activities are presented. [ABSTRACT FROM AUTHOR]

This paper introduces recent improvements for reactor physics codes in Mitsubishi Heavy Industries, Ltd(MHI). MHI has developed a new neutronics design code system Galaxy/Cosmo-S(GCS) for PWR core analysis. After TEPCO's Fukushima Daiichi accident, it is required to consider design extended condition which has not been covered explicitly by the former safety licensing analyses. Under these circumstances, MHI made some improvements for GCS code system. A new resonance calculation model of lattice physics code and homogeneous cross section representative model for core simulator have been developed to apply more wide range core conditions corresponding to severe accident status such like anticipated transient without scram (ATWS) analysis and criticality evaluation of driedup spent fuel pit. As a result of these improvements, GCS code system has very wide calculation applicability with good accuracy for any core conditions as far as fuel is not damaged. In this paper, the outline of GCS code system is described briefly and recent relevant development activities are presented. [ABSTRACT FROM AUTHOR]

With the latest advances in attainable laser intensity, the need to obtain better quality ion and electron beams has been a major field of research. This paper studies the effects of different target density profiles on the spatial distribution of the accelerated particles, the maximum energies achieved, and the characteristics of the electromagnetic fields using the same laser pulse parameters. The study starts by describing a baseline for a flat target which presents a proton-rich microdot on its backside. The effects of introducing a target curvature and, further on, a cone laser focusing structure are compared with the flat target baseline results. The maximum energy obtained increases when using complex structures, and also a smaller divergence of the ion beam is observed. [ABSTRACT FROM AUTHOR]

To date conventional use of dielectric-lined waveguides (DLWs) has mainly concerned high-gradient acceleration. In this paper we investigate an alternative use of such waveguides to impressed wakefield-induced energy correlations on non-ultra-relativistic beams. These correlations are shown to produce density modulations as the beam drifts in a free space. We explore several schemes with a single or multiple DLW structures which can lead to passive compressions and to the formation of sub-picosecond bunch trains. We finally suggest the possible use of multiple structures to bunch the beam at higher frequencies using a scheme similar to a two-stage echo enabled harmonic generation. [ABSTRACT FROM AUTHOR]

This paper presents a new approach to form 3D structures by transferring and stacking pre-patterned, freestanding silicon membranes and demonstrate the process by fabricating 17-layer woodpile 3D photonic crystals, which has complete 3D photonic band gap, and relatively simple structure for the application of Dielectric Laser-driven Accelerator. [ABSTRACT FROM AUTHOR]

Recently it was proposed in [A. F. Lifschitz, et. al., J. Comp. Phys. 228, 1803 (2009)] that laser wakefield acceleration could be modeled efficiently using a particle-in-cell code in cylindrical coordinates if the fields and currents were expanded into Fourier modes in the azimuthal angle, φ. We have implemented this algorithm into OSIRIS, including a new rigorous charge conserving deposition routine applicable for it [A. Davidson, et. al., J. Comp. Phys. 281, 1063 (2014)]. This algorithm can be interpreted as a PIC description in r??z and a gridless description in φ in which the expansion into φ modes is truncated at a desired level. This new quasi-3D algorithm greatly reduces the computational load by describing important three-dimensional (3D) geometrical effects with nearly two-dimensional calculations. In this paper, we propose to combine this algorithm with the Lorentz boosted frame method for simulations of Laser wakefield acceleration (LWFA). We show preliminary results, including an investigation of the unstable numerical Cerenkov instability modes for this geometry, and discuss directions for future work. These preliminary results indicate that combining the quasi-3D method and the Lorentz boosted frame method together may provide unprecedented speed ups for LWFA simulations. [ABSTRACT FROM AUTHOR]

Laser-plasma accelerators can produce a few GeV electron beams over a distance of a few cm. Such beams typically have relatively low emittance and high peak current but a rather large energy spread and jitter. The large energy spread hinders the potential applications for coherent free-electron laser (FEL) radiation generation. In this paper, we discuss a method to compensate the effects of beam energy spread by introducing a transverse variation of the undulator magnetic field. Such a transverse gradient undulator (TGU) together with a properly dispersed beam can greatly reduce the effects of electron energy spread and jitter on FEL performance. We review the TGU concept and theory and discuss technical implementations. Using particle-in-cell simulations of a GeV laser-plasma accelerator and the FEL simulation code GENESIS that is modified to accommodate TGU, we show a soft x-ray FEL operating in the "water window" wavelengths can reach saturation with a undulator length of about 12 m. [ABSTRACT FROM AUTHOR]

Recent progress in the generation of high-quality, high-current electron beams has enabled the development of structure based wakefield accelerators in use. The frequency spectrum available using these sources ranges from GHz to THz depending on the parameters of the beam and waveguide (dielectric-lined or metallic disk-loaded). In this paper, we discuss the choice of structure and beam parameters to achieve an efficient wakefield acceleration. [ABSTRACT FROM AUTHOR]

SC200 is an isochronous cyclotron which generate 200 MeV, 500 nA proton for particle therapy. As an important component of the cyclotron, the ion source chimney needs to be tested and optimized. The simulation results and optimization of ion source in test bench for SC200 are described in this paper. The simulation results show that the extraction slit with different sizes and shapes has an influence on the emittance of the extraction beam. To verify the simulation results, the performance of the designed ion source chimney with optimized slits was measured, including the beam current intensity and the beam emittance. [ABSTRACT FROM AUTHOR]

The discrepancy between the proton charge radius extracted from the muonic hydrogen Lamb shift measurement and the best present value obtained from the elastic scattering experiments, remains unexplained and represents a burning problem of today's nuclear physics: after more than 50 years of research the radius of a basic constituent of matter is still not understood. This paper presents a summary of the best existing proton radius measurements, followed by an overview of the possible explanations for the observed inconsistency between the hydrogen and the muonic-hydrogen data. In the last part the upcoming experiments, dedicated to remeasuring the proton radius, are described. [ABSTRACT FROM AUTHOR]

Collisions of asymmetric nuclei (Cu+Au) differ essentially from the case of symmetric nuclei (Cu+Cu, Au+Au) collisions in the geometry of overlap region. This leads to a number of consequences, which provide more absolute and accurate information about fundamental properties of matter under extreme conditions. Nuclear modification factors for π-mesons in Cu+Au interactions at 200 GeV were measured in PHENIX Experiment at RHIC. New experimental data on measurement of flows of different order (v1, v2) for light hadrons in Cu+Au interactions at 200 GeV will be discussed in this paper. [ABSTRACT FROM AUTHOR]

The discrepancy between the proton charge radius extracted from the muonic hydrogen Lamb shift measurement and the best present value obtained from the elastic scattering experiments, remains unexplained and represents a burning problem of today's nuclear physics: after more than 50 years of research the radius of a basic constituent of matter is still not understood. This paper presents a summary of the best existing proton radius measurements, followed by an overview of the possible explanations for the observed inconsistency between the hydrogen and the muonic-hydrogen data. In the last part the upcoming experiments, dedicated to remeasuring the proton radius, are described. [ABSTRACT FROM AUTHOR]

An RF amplifier system was designed and is under construction at the UCLA Basic Plasma Science Facility. The system is designed to output 200 kW peak RMS power at 1% duty cycle with a 1 Hz rep rate at frequencies of 2-6 MHz. This paper describes the RF amplifier system with preliminary benchmarks. Current design challenges and future work are discussed. [ABSTRACT FROM AUTHOR]

Metal-loaded liquid scintillator plays a key role in particle and nuclear physics experiments. The applications of metal ions in various neutrino experiments and the purification methods for different scintillator components are discussed in this paper. [ABSTRACT FROM AUTHOR]

Hadronic mechanics gave birth to new magnecular fuels. The present day demand is of clean energy source that is cheap and abundant. Clean energy can be obtained by harnessing renewable energy sources like solar, wind etc. Nuclear energy conventionally produced by fission reactions emits hazardous radiation and radioactive waste. The requirements of clean and safe energy gets fulfilled by novel fuel that achieved by elevating the traditional quantum mechanics to hadronic mechanics and to hadronic chemistry. In the present paper, a comprehensive review on both the theoretical and experimental aspect of the Intermediate Controlled Nuclear Synthesis (ICNS) as developed by Italian American Scientist Professor R. M. Santilli. [ABSTRACT FROM AUTHOR]

The research program of the Extreme Light Infrastructure - Nuclear Physics (ELI-NP) laboratory under construction in Magurele, Romania facilities the need of developing a gaseous active-target detector providing 3D reconstruction of charged products of nuclear reactions induced by gamma beam. The monoenergetic, high-energy (Eγ >19 MeV) gamma beam of intensity 1013γ/s allows studying nuclear reactions in astrophysics. A Time Projection Chamber with crossed strip readout (eTPC) is proposed as one of the imaging detectors. The special feature of the readout electrode structure is a 2D reconstruction based on the information read out simultaneously from three arrays of strips that form virtual pixels. It is expected to reach similar spatial resolution as for pixel readout at largely reduced cost of electronics. The paper presents the current progress and first results of the small scale prototype TPC which is a one of implementation steps towards eTPC detector proposed in the Technical Design Report of Charged Particles Detection at ELI-NP. [ABSTRACT FROM AUTHOR]

The Project Extreme Light Infrastructure (ELI) is part of the European Strategic Forum for Research Infrastructures (ESFRI) Roadmap. ELI will be built as a network of three complementary pillars at the frontier of laser technologies. The ELI-NP pillar (NP for Nuclear Physics) is under construction near Bucharest (Romania) and will develop a scientific program using two 10 PW lasers and a Compton back-scattering high-brilliance and intense gamma beam, a marriage of laser and accelerator technology at the frontier of knowledge. In the present paper, the technical description of the facility, the present status of the project as well as the science, applications and future perspectives will be discussed. [ABSTRACT FROM AUTHOR]

Initially, yields (or abundances) and branching ratios of β-delayed neutrons (βdn) from fission products (Pn-values) have had their main importance in nuclear reactor control. At that time, the six-group mathematical approximation of the time-dependence of βdn-data in terms of the so-called "Keepin groups" was generally accepted. Later, with the development of high-resolution neutron spectroscopy, ßdn data have provided important information on nuclear-structure properties at intermediate excitation energy in nuclei far from stability, as well as in nuclear astrophysics. In this paper, I will present some examples of the βdn-studies performed by the Kernchemie Mainz group during the past three decades. This work has been recognized as an example of "broad scientific diversity" which has led to my nomination for the 2014 Hans A. Bethe prize. [ABSTRACT FROM AUTHOR]