Field Of Nuclear Physics Research Articles

Some aspects of fission and quasifission processes

The discovery of nuclear fission in 1938–1939 had a profound influence on the field of nuclear physics and it brought this branch of physics into the forefront as it was recognized for having the potential for its seminal influence on modern society. Although many of the basic features of actinide fission were described in a ground-breaking paper by Bohr and Wheeler only six months after the discovery, the fission process is very complex and it has been a challenge for both experimentalists and theorists to achieve a complete and satisfactory understanding of this phenomenon. Many aspects of nuclear physics are involved in fission and it continues to be a subject of intense study even three quarters of a century after its discovery. In this talk, I will review an incomplete subset of the major milestones in fission research, and briefly discuss some of the topics that I have been involved in during my career. These include studies of vibrational resonances and fission isomers that are caused by the second minimum in the fission barrier in actinide nuclei, studies of heavy-ion-induced fission in terms of the angular distributions and the mass–angle correlations of fission fragments. Some of these studies provided evidence for the importance of the quasifission process and the attendant suppression of the complete fusion process. Finally, some of the circumstances around the establishment of large-scale nuclear research in India will be discussed.

Future Experiments with Intense Laser Beams and Brilliant Gamma Beams at the ELI-NP Facility

The Extreme Light Infrastructure (ELI) Pan-European facility initiative represents a major step forward in quest for extreme electromagnetic fields. Extreme Light Infrastructure Nuclear Physics (ELI-NP) is one of the three pillars of the ELI facility, that aims to use extreme electromagnetic fields for nuclear physics and quantum electrodynamics research. At ELI-NP, high-power lasers together with a very brilliant gamma beam are the main research tools. Their targeted operational parameters are described. The emerging experimental program in the field of nuclear physics of the facility is reported. The different instruments which are considered to operate in the ELI-NP experimental halls are discussed, with an emphasis on the instrumentation which is designed for nuclear structure, reactions and astrophysics research.

Radioactive nuclear beams: Present and future

Some results of investigations into a new nuclear-physics field associated with the production of radioactive nuclear beams and physical studies with these beams are presented. The most recent results obtained by studying the structure of nuclei and reaction mechanisms with radioactive nuclear beams are surveyed. Data obtained in Dubna at the DRIBs accelerator complex are presented along with allied results from other research centers. In this connection, existing experimental data on light loosely bound exotic nuclei are discussed. The parameters of DRIBs3, which is a new accelerator complex, are presented, and the physics research program that will be implemented with the aid of new setups, including a high-resolution magnetic analyzer (MAVR) and a 4π neutron detector (TETRA), is described. A collaboration in the realms of employing radioactive nuclear beams at the DRIBs complex together with other accelerator complexes [SPIRAL2 (France), RIKEN (Japan), FAIR (Germany), and RIBF (CIIIA)] on the basis of employing new highly efficient experimental facilities has already led to the discovery of new phenomena in nuclear physics and will make it possible to study in the future new regions of nuclear matter in extreme states.

Non-equilibrium plasma produced by intense pulse lasers and relative diagnostics

Non-equilibrium plasmas generated by pulsed laser intensities between 1010 and 1016 W cm−2 can be produced in high vacuum conditions. Thick and thin irradiated targets show non-isotropic radiation emission of photons, electrons and ions. High energetic ions, emitted along the normal to the target surface, are driven by high electric fields developed in plasma charge separation. Plasmas are characterized in terms of equivalent temperature, density, particle energy distributions and angular distribution, ion charge state distributions and the ion acceleration driving field.Plasma diagnostic methods are based mainly on time-of-flight techniques using ion collectors, SiC semiconductor detectors and ion energy analysers. Thomson parabola spectrometry, track detection and mass spectrometry give further characterizations.Investigations demonstrated that plasma properties depend strongly on the laser's characteristics, target composition and irradiation conditions. Results relative to ion and proton acceleration appear very interesting for many applications in the field of nuclear physics, matter structure, microelectronics, biology and medicine.

Working characteristics of the New Low-Background Laboratory (DULB-4900)

The Baksan Neutrino Observatory of the Institute for Nuclear Research of the Russian Academy of Science is one of the first and biggest underground laboratories in the world specially constructed to carry out different types of experiments in the field of nuclear physics, particle and astroparticle physics. Main technical characteristics of the new low-background laboratory DULB-4900 of the BNO are presented. The laboratory is located at a distance of 3700m from the main entrance of the observatory tunnel in the hall with dimensions ~6×6×40m3. Thickness of the mountain rock over DULB corresponds to 4900m w.e. and this deep location provides the cosmic ray flux reduction with the factor of about 107. The methods and results of the background level measurements both in the hall and operating facilities are given. Contamination of the radioactive 222Rn gas has been also measured in the air by using direct detection of γ-radiation of its daughter 214Bi distributed inside the volume of the low-background chamber. The results of the data analysis are presented and discussed.

Multiple-reflection time-of-flight mass spectrometry

Multiple-reflection time-of-flight mass spectrometry is an emerging technique that meets the challenges of mass spectrometry at current and future accelerator facilities for the research with exotic nuclei. Moreover, many new applications in analytical mass spectrometry appear on the horizon. In a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) the analyzer is traversed many times by the ions, extending the flight path by several orders of magnitude over conventional time-of-flight mass spectrometers (TOF-MS). MR-TOF-MS thus allow to achieve a very high mass resolving power (>100,000) in a compact device. They combine the advantages of conventional TOF-MS, viz. extremely short measurement times (∼ ms), a large mass range, very high sensitivity and non-scanning operation, with very high mass resolving power and accuracy. MR-TOF-MS can serve as devices for high-accuracy mass measurements of very short-lived nuclei, as high-resolution mass separators, and as broadband mass spectrometers for diagnostic purposes. In this article, an overview of MR-TOF-MS developments for the research with short-lived nuclei is given. Different instrumental implementations are reviewed. Despite the same operation principle, different instrumental solutions exist, which give rise to significant differences in applicability and performance. A novel performance criterion for mass spectrometers for the research with exotic nuclei is presented, and a performance increase for MR-TOF-MS of at least one order of magnitude compared to the established technique of TOF-ICR is found. The MR-TOF-MS for the Low-Energy Branch of the Super-FRS at the Facility for Antiproton and Ion Research (FAIR), which has recently been commissioned at the FRS Ion Catcher at GSI, is presented in some detail. Applications of MR-TOF-MS at accelerator facilities as well as their scientific potential outside the field of nuclear physics are discussed.

Deuteron Induced (d,p) and (d,2p) Nuclear Reactions up to 50 MeV

Many studies have shown that the nuclear reactions of charged particles with nuclei are very important in many fields of nuclear physics. The interactions of deuterons with nuclei have been especially the subject of common research in the history of nuclear physics. Moreover, the knowledge of cross section for deuteron-nucleus interactions are required for various application such as space applications, accelerator driven sub-critical systems, nuclear medicine, nuclear fission reactors and controlled thermonuclear fusion reactors. Particularly, the future of controlled thermonuclear fusion reactors is largely dependent on the nuclear reaction cross section data and the selection of structural fusion materials. Finally, the reaction cross section data of deuteron induced reactions on fusion structural materials are of great importance for development and design of both experimental and commercial fusion devices. In this work, reaction model calculations of the cross sections of deuteron induced reactions on structural fusion materials such as Al (Aluminium), Ti (Titanium), Cu (Copper), Ni (Nickel), Co (Cobalt), Fe (Iron), Zr (Zirconium), Hf (Hafnium) and Ta (Tantalum) have been investigated. The new calculations on the excitation functions of 27Al(d,2p)27Mg, 47Ti(d,2p)47Sc, 65Cu(d,2p)65Ni, 58Ni(d,2p)58Co, 59Co(d,2p)59Fe, 58Fe(d,p)59Fe, 96Zr(d,p)97Zr, 180Hf (d,p)181Hf and 181Ta(d,p)182Ta have been carried out for incident deuteron energies up to 50 MeV. In these calculations, the equilibrium and pre-equilibrium effects for (d,p) and (d,2p) reactions have been investigated. The equilibrium effects are calculated according to the Weisskopf-Ewing (WE) Model. The pre-equilibrium calculations involve the new evaluated the Geometry Dependent Hybrid Model (GDH) and Hybrid Model. In the calculations the program code ALICE/ASH was used. The calculated results are discussed and compared with the experimental data taken from the literature.

Rutherford, Radioactivity and the Origins of Nuclear Physics

When Ernest Rutherford became Professor of Physics at Manchester University in 1907, he brought with him the research field in which he had played a leading role over the previous few years: radioactivity. Rutherford turned the Manchester physics lab over to studies of radioactivity and radiation, and through his own work and that of his many collaborators and students, established Manchester as a major international centre in atomic physics. It was out of this powerhouse that the nuclear theory of the atom emerged in 1911.In 1917, Rutherford 'disintegrated' the nitrogen nucleus using α-particles, opening up the possibility of nuclear structure. At Cambridge's Cavendish Laboratory from 1919, Rutherford and his co-workers began to explore the constitution of the nucleus. With Chadwick, Aston and others, Rutherford turned his research school to the emergent field of nuclear physics – a field he dominated (though not without controversy) until his death in 1937.Exploring the intellectual, material and institutional cultures of early twentieth century physics, this paper will outline the background to Rutherford's career and work, the experimental and theoretical origins of nuclear theory of the atom and the early development of nuclear physics.

Progress on the Lanzhou Penning Trap

The Penning trap is one of the most important experimental devices in the field of nuclear physics, and measures atomic masses with the highest precision in the world. Many such devices are currently in operation, with more being designed and constructed. To start the experimental study of atomic masses with very high precision in China, the Lanzhou Penning Trap (LPT) is being constructed at the Institute of Modern Physics, Chinese Academy of Sciences. In this paper the progress and status of the LPT will be reported.

The 2007 U.S. NIE on Iran's Nuclear Program: A Colossal Failure

Click to increase image sizeClick to decrease image size Additional informationNotes on contributorsDany ShohamDr. Dany Shoham, a senior researcher at the Begin-Sadat Center for Strategic Studies, Bar-Ilan University, Ramat-Gan, Israel, was previously a senior analyst and lieutenant colonel in the Israel Defense Forces intelligence. He investigates proliferation issues related to weapons of mass destruction in the Middle East.Raphael OfekDr. Raphael Ofek, an expert in the field of nuclear physics, was previously a senior analyst and lieutenant colonel in the Israel Defense Forces intelligence.

Few-Body Aspects of Hypernuclear Physics

Recent development in the study of the structure of light Λ and double Λ hypernuclei is reviewed from the view point of few-body problems and interactions between the constituent particles. In the study the present author and collaborators employed Gaussian expansion method for few-body calculations; the method has been applied to many kinds of few-body systems in the fields of nuclear physics and exotic atomic/molecular physics. We reviewed the following subjects studied using the method: (1) Precise three- and four-body calculations of $${^7_{\Lambda}{\rm He}}$$ , $${^7_{\Lambda}{\rm Li}}$$ , $${^7_{\Lambda}{\rm Be}}$$ , $${^8_{\Lambda}{\rm Li}}$$ , $${^8_{\Lambda}{\rm Be}}$$ , $${^9_{\Lambda}{\rm Be}}$$ , $${^{10}_{\Lambda}{\rm Be}}$$ , $${^{10}_{\Lambda}{\rm B}}$$ and $${^{13}_{\Lambda}{\rm C}}$$ provide important information on the spin structure of the underlying Λ N interaction by comparing the calculated results with the recent experimental data by γ-ray hypernuclear spectroscopy. (2) The Λ-Σ coupling effect was investigated in $${^4_{\Lambda}{\rm H}}$$ and $${^4_{\Lambda}{\rm He}}$$ on the basis of the N + N + N + Λ (Σ) four-body model. (3) A systematic study of double-Λ hypernuclei and the Λ Λ interaction, based on the NAGARA event data ( $${^6_{\Lambda\Lambda}{\rm He}}$$ ), was performed within the α + x + Λ + Λ cluster model (x = n, p, d, t,3He and α) and α + α + n + Λ + Λ cluster model, (4) The Demachi-Yanagi event was interpreted as observation of the 2+ state of $${^{10}_{\Lambda \Lambda}{\rm Be}}$$ , (5) The Hida event was interpreted as observation of the ground state of $${^{11}_{\Lambda \Lambda}{\rm Be}}$$ .

Nuclear symmetry energy in calcium-calcium collisions (INDRA-VAMOS)

The density dependence of the symmetry energy is of great interest to many fields of nuclear physics and nuclear astro-physics. The E503 INDRA-VAMOS experiment performed at GANIL in 2007 is intended to provide further sub-saturation constraints using calcium-calcium collisions around the Fermi energy (35AMeV). In these proceedings this experiment will be discussed in the context of the physics it is aiming to study and will give a brief summary of the current progress of the data analysis.

Centro Nacional de Aceleradores (CNA), Sevilla, Spain

The National Accelerator Centre (CNA) is a Spanish joint institution that, since its creation in 1998, has the mission of carrying out research in particle accelerators and its multiple applications. This article aims to perform a summary of the structure and the facilities of the Centre, while it also contains information about the most recent lines of research with an accent on those belonging to the nuclear physics field. In this way, we want to show the capabilities of CNA, in order to promote collaborations with the scientific and technological communities. The CNA is recognized as an Spanish Singular Scientific and Technological Facility, and it is a users-oriented laboratory, open to the Spanish and the international scientific community belonging to universities, public research institutions, public and private companies, hospitals, or other institutions that require the use of the facilities.

Nuclear Physics Institute of the ASCR

The Nuclear Physics Institute of the ASCR (NPI), a public research organization, is the major Czech institution in the field of nuclear physics. The institute, belonging to the Academy of Science of the Czech Republic, is located together with some other research organizations at the area of village Řež about 20 km north of Prague (see issue cover). The institute's staff comprises about 200 people including about 90 researchers. Moreover, about 35–40 diploma and Ph.D. students do their work at the NPI laboratories.

Recent results of the laser ion source facility at INFN-LNS and applications to nuclear and applied research

A pulsed neodymium-doped yttrium aluminum garnet laser ion source has been used as proton beams generator. The laser wavelength is 1064 nm, the pulse duration is 9 ns and the intensity reaches 10(10) W/cm(2). Laser irradiates hydrogenated polymers targets located in a chamber at 10(-7) mbar. The ions are post-accelerated in a suitable chamber by 30 kV of voltage between the target, positively biased, and the following ground electrode. The extracted beams is characterized through a time-of-flight technique. Possible applications to the field of nuclear physics, such as nuclear excitation and de-excitations, nuclear reactions and nuclear fusion, will be presented and discussed.

Nuclear applications of inorganic mass spectrometry

There are several basic characteristics of mass spectrometry that are not always fully appreciated by the science community. These characteristics include the distinction between relative and absolute isotope abundances, and the influence of isotope fractionation on the accuracy of isotopic measurements. These characteristics can be illustrated in the field of nuclear physics with reference to the measurement of nuclear parameters, which involve the use of enriched isotopes, and to test models of s-, r-, and p-process nucleosynthesis. The power of isotope-dilution mass spectrometry (IDMS) to measure trace elements in primitive meteorites to produce accurate Solar System abundances has been essential to the development of nuclear astrophysics. The variety of mass spectrometric instrumentation used to measure the isotopic composition of elements has sometimes been accompanied by a lack of implementation of basic mass spectrometric protocols which are applicable to all instruments. These metrological protocols are especially important in atomic weight determinations, but must also be carefully observed in cases where the anomalies might be very small, such as in studies of the daughter products of extinct radionuclides to decipher events in the early history of the Solar System. There are occasions in which misleading conclusions have been drawn from isotopic data derived from mass spectrometers where such protocols have been ignored. It is important to choose the mass spectrometer instrument most appropriate to the proposed experiment. The importance of the integrative nature of mass spectrometric measurements has been demonstrated by experiments in which long, double beta decay and geochronological decay half-lives have been measured as an alternative to costly radioactive-counting experiments. This characteristic is also illustrated in the measurement of spontaneous fission yields, which have accumulated over long periods of time. Mass spectrometry is also a valuable tool in the determination of neutron capture cross-section measurements and the application of such determinations in Planetary Science.

Analytical evaluation of Doppler functions arising from resonance effects in nuclear processes

We present a new method for the analytical evaluation of Doppler function arising from resonance effects in nuclear processes. The method yields stable results in nuclear physics field avoiding complicated analytic approximations. Explicit formulas for the Doppler function are developed in terms of series of binomial coefficients and incomplete functions. The obtained results permit a very fast evaluation of Doppler function with a degree of accuracy higher than the one required for nuclear resonance absorption. Implementation in a computer program of our approach is described.

Perspective on the Development of Nuclear Physics in the Past 100 Years

The course of nuclear physics is reviewed in the period from just before Hideki Yukawa's birth through the middle of the 20th century. Some information on Yukawa's first paper is presented. Then some general observations about the present state of the field of nuclear physics and of science are given.

Benchmarking of calculated projectile fragmentation cross-sections using the 3-D, MC codes PHITS, FLUKA, HETC-HEDS, MCNPX_HI, and NUCFRG2

Particles and heavy ions are used in various fields of nuclear physics, medical physics, and material science, and their interactions with different media, including human tissue and critical organs, have therefore carefully been investigated both experimentally and theoretically since the 1930s. However, heavy-ion transport includes many complex processes and measurements for all possible systems, including critical organs, would be impractical or too expensive; e.g. direct measurements of dose equivalents to critical organs in humans cannot be performed. A reliable and accurate particle and heavy-ion transport code is therefore an essential tool in the design study of accelerator facilities as well as for other various applications. Recently, new applications have also arisen within transmutation and reactor science, space and medicine, especially radiotherapy, and several accelerator facilities are operating or planned for construction. Accurate knowledge of the physics of interaction of particles and heavy ions is also necessary for estimating radiation damage to equipment used on space vehicles, to calculate the transport of the heavy ions in the galactic cosmic ray (GCR) through the interstellar medium, and the evolution of the heavier elements after the Big Bang. Concerns about the biological effect of space radiation and space dosimetry are increasing rapidly due to the perspective of long-duration astronaut missions, both in relation to the International Space Station and to manned interplanetary missions in near future. Radiation protection studies for crews of international flights at high altitude have also received considerable attention in recent years. There is therefore a need to develop accurate and reliable particle and heavy-ion transport codes. To be able to calculate complex geometries, including production and transport of protons, neutrons, and alpha particles, 3-dimensional transport using Monte Carlo (MC) technique must be used. Today several particle and heavy-ion MC transport codes exist, e.g. Particle and Heavy-Ion Transport code System (PHITS), High Energy Transport Code-Human Exploration and Development of Space (HETC-HEDS), SHIELD-HIT, GEANT4, FLUKA, MARS, and MCNPX. In this paper, we present an extensive benchmarking of the calculated projectile fragmentation cross-sections from the reactions of 300 – 1000 MeV / u 28Si, 40Ar, and 56Fe on polyethylene, carbon, aluminum, and copper targets (relevant to space radioprotection) using PHITS, FLUKA, HETC-HEDS, and MCNPX, against measurements. The influence of the different models used in the different transport codes on the calculated results is also discussed. Some measured cross-sections are also compared to the calculated cross-sections using NUCFRG2, which are incorporated in the 1-dimensional, deterministic radiation transport code HZETRN.

Handling uncertainty

The management of health risks related to scientific and technological innovations has been the focus of a heated debate for a few years now. In some cases, like the campaigns against the use of GMOs in agriculture, this debate has degenerated into a political and social dispute. Even risk analysis studies, which appeared in the 1970s in the fields of nuclear physics and engineering and were later developed by social sciences as well, have given completely different, and at times contradictory, interpretations that, in turn, have given rise to bitter controversies.