Nuclear Physics Facility Research Articles

The ELI–NP facility for nuclear physics

Extreme Light Infrastructure–Nuclear Physics (ELI–NP) is aiming to use extreme electromagnetic fields for nuclear physics research. The facility, currently under construction at Magurele–Bucharest, will comprise a high power laser system and a very brilliant gamma beam system. The technology involved in the construction of both systems is at the limits of the present-day’s technological capabilities. The high power laser system will consist of two 10PW lasers and it will produce intensities of up to 1023–1024W/cm2. The gamma beam, produced via Compton backscattering of a laser beam on a relativistic electron beam, will be characterized by a narrow bandwidth (<0.5%) and tunable energy of up to almost 20MeV. The research program of the facility covers a broad range of key topics in frontier fundamental physics and new nuclear physics. A particular attention is given to the development of innovative applications. In the present paper an overview of the project status and the overall performance characteristics of the main research equipment will be given. The main fundamental physics and applied research topics proposed to be studied at ELI–NP will also be briefly reviewed.

Jefferson Lab Science: Present and Future

The continuous electron beam accelerator facility and associated experimental equipment at Jefferson Lab comprise a unique facility for experimental nuclear physics. This facility is presently being upgraded, which will enable a new experimental program with substantial discovery potential to address important topics in nuclear, hadronic, and electroweak physics. Further in the future, it is envisioned that the Laboratory will evolve into an electron-ion colliding beam facility.

Correlation between effective and ambient neutron doses in radiation fields of nuclear-physics facilities at the joint institute for nuclear research

The questions of a correlation between normative and operational quantities in the dosimetry of ionizing radiation still attract the attention of professionals working in the field. Since the neutron fields of nuclear-physics facilities at the Joint Institute for Nuclear Research (JINR) are highly varied, the question of whether the ambient neutron dose always serves as a conservative estimate of the effective dose (in the terms of which the dose limits are set) is of practical importance for radiation monitoring at JINR. We studied the correlation between the calculated values of effective and ambient neutron doses obtained based on a representative set of neutron spectra measured at JINR with the use of a multisphere neutron spectrometer. It is demonstrated that measuring the ambient neutron dose may not serve as a confirmation of compliance with the set dose limits in “hard” neutron fields.

Active Target detectors for studies with exotic beams: Present and next future

Reaccelerated radioactive beams near the Coulomb barrier, which are starting to be available from the ReA3 accelerator at NSCL and in next future at FRIB, will open up new opportunities for the study of nuclear structure near the drip lines. Efficient measurement techniques must be developed to compensate for the limited intensity of the most exotic beams. The Active-Target Time Projection Chamber (AT-TPC) constructed at MSU solves this problem by providing the increased luminosity of a thick target while maintaining a good energy resolution by tracking the reaction vertex over an essentially 4π solid angle. The AT-TPC and similar detectors allow us to take full advantage of the radioactive ion beams at present and future nuclear physics facilities to explore the frontier of rare isotopes.

Keynote address: One hundred years of nuclear physics – Progress and prospects

Nuclear physics research is growing on several fronts, along energy and intensity frontiers, with exotic projectiles and targets. The nuclear physics facilities under construction and those being planned for the future make the prospects for research in this field very bright.

Henry Gabriel Blosser

Henry Gabriel Blosser

US nuclear physics facilities on the chopping block

The country stands to lose leadership in at least some areas of the field as funding agencies decide where the axe will fall.

The ELI-Nuclear Physics Project

The Extreme Light Infrastructure - Nuclear Physics facility (ELI-NP) to be constructed in Bucharest-Magurele will be one of the three pillars of ELI and will consist of two components: a very high intensity laser beam and a very intense (1013 γ/s), brilliant γ beam, 0.1% bandwidth, with Eγ = 19 MeV. ELI-NP will allow either combined experiments between the high-power laser and the γ beam or stand-alone experiments. This facility will create a new European laboratory with a broad range of science covering frontier fundamental physics, new nuclear physics and astrophysics as well as applications. A review of the Project and the Status of its implementation will be presented.

Construction and Status of the Hadron Experimental Hall

On January 27, 2009, protons were accelerated by the 50GeV proton synchrotron (50GeV-PS) of the Japan Proton Accelerator Research Complex (J-PARC) up to its initial goal of 30GeV, and were successfully extracted for the first time to the Hadron Experimental Hall in the Particle and Nuclear Physics Facility of J-PARC. On February 10th, secondary particles such as kaons and pions were extracted to the experimental area of the Hadron Experimental Hall through the secondary particle beam line. Then the physics experiments started.

Hadron Experimental Hall

On January 27, 2009, protons were accelerated by 50 GeV Proton Synchrotron (50 GeV-PS) up to 30 GeV, at which we will operate the PS at the first phase of the project, and successfully extracted to Hadron Experimental Hall in Nuclear and Particle Physics Facility and transported to the beam dump [1]. Hadron Experimental Hall is one of the two facilities at 50 GeV-PS and utilizes the various kinds of secondary particles generated by protons. To make plenty of secondary particles by the high intensity proton beam available for experiments, many methods of handling the high intensity beam have been developed for this facility. In particular, a firm radiation shield was constructed and magnets that were hard to break and easy to be replaced, in case of trouble in the high radiation area, were produced.

Decommissioning and Safety Issues of Liquid-Mercury Waste Generated from High-Power Spallation Sources with Particle Accelerators

Large spallation sources are intended to be constructed in Europe (EURISOL nuclear physics facility and European Spallation Source). These facilities accumulate more than 20 tonnes of irradiated mercury in the target, which has to be treated as highly radioactive and chemotoxic waste. Because solids are the only appropriate (immobile) form for this radiotoxic and toxic type of waste, solidification is required for irradiated mercury. Our irradiation experimental studies on mercury waste revealed that mercury sulfide is a reasonable solid for disposal and shows larger stability in assumed accidents with water ingress in a repository compared to amalgams. For preparation of mercury sulfide, a wet process is more suitable than a dry one. It is easier to perform under hot cell conditions and allows complete Hg conversion. Embedding HgS in a cementitious matrix increases its stability.

DOE Picks Michigan State Lab for Rare-Isotope Accelerator

NUCLEAR PHYSICS A relatively small university lab has beat out a much larger national lab in the competition to host a $550 million accelerator facility for nuclear physics. The U.S. Department of Energy (DOE) announced last week that it would build the Facility for Rare Isotope Beams (FRIB) at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) in East Lansing instead of at its own Argonne National Laboratory in Illinois. Many had expected Argonne's superior infrastructure and $530 million budget to give it a decisive edge. The MSU proposal “started out as a long shot,” admits C. Konrad Gelbke, director of NSCL, whose $20-million-a-year budget is provided by the U.S. National Science Foundation. “But I always felt very optimistic that if you presented the case in a very open and honest way, it would all level out in the end.” Argonne officials said in a statement that they were “disappointed” and noted that “much of the science for FRIB was developed here at the laboratory.” FRIB will serve as a source of exotic and fleeting radioactive nuclei. The heart of the machine will consist of a 400-meter-long high-intensity linear accelerator that can accelerate a nucleus of any weight from hydrogen to uranium. Those nuclei will smash into and through targets to make beams of exotic isotopes, which will then be used to refine existing theories of nuclear structure, probe fundamental symmetries of nature, and help unravel the processes in stellar explosions that presumably produce half the elements heavier than iron. FRIB would pump out beams at least 1000 times more intense than those currently produced at NSCL. The site selection “was not the easiest of decisions,” says Eugene Henry, DOE's acting associate director for nuclear physics. Henry declined to discuss the details of the two proposals but noted that MSU had offered to pay some of the construction costs. The university has committed to chipping in $94 million, says MSU spokesperson Terry Denbow. He did not say how the money would be raised. ![Figure][1] New foundation. Housed in a tunnel (gray), the new accelerator would feed experiments in the existing lab. CREDIT: MICHIGAN STATE UNIVERSITY DOE also had more confidence in MSU's spending plan, says Donald Levy, vice president for research and for national laboratories at the University of Chicago in Illinois, which contracts with DOE to run Argonne. “The budget part of their proposal was deemed to be more reliable than ours,” Levy says, in part because MSU's budget included more “contingency” money to cover possible cost overruns. Some observers have misgivings about building a large facility at such a small lab. “[T]he scale of the project was more appropriate for one of the existing DOE laboratories,” says Burton Richter, a particle physicist and former director of DOE's SLAC National Accelerator Laboratory in Menlo Park, California. But Richard Casten, a nuclear physicist at Yale University, says he's sure that NSCL is up to the task: “I have no worries about that at all.” Many scientists are just glad that the project, originally proposed in the late 1990s, is making progress. “We are happy that the decision has been made and that the excellent team at Michigan State has been chosen,” says Witold Nazarewicz, a nuclear theorist at the University of Tennessee, Knoxville. Researchers hope to start detailed design work next year and to have the machine built and running in about a decade. [1]: pending:yes

Michigan State awarded nuclear physics facility

Michigan State awarded nuclear physics facility

Extension of the Monte-Carlo code MOCADI to fusion-evaporation reactions

The Monte-Carlo code MOCADI has been extended, besides to fission and fragmentation reactions, also to fusion-evaporation reactions. The updated version includes the cross sections and the reaction kinematics for the production of evaporation residues calculated according to the statistical model code PACE2, while the atomic interaction with matter can be treated either with the code ATIMA or with the code TRIM. The present version of MOCADI can now be employed world-wide for design studies of new low-energy nuclear physics facilities and for the optimization of experiments involving fusion-evaporation reactions, e.g. mass measurements, laser spectroscopy, super-heavy synthesis.

Simon Peter Rosen

Simon Peter Rosen

ENDF/B-VII.0: Next Generation Evaluated Nuclear Data Library for Nuclear Science and Technology

We describe the next generation general purpose Evaluated Nuclear Data File, ENDF/B-VII.0, of recommended nuclear data for advanced nuclear science and technology applications. The library, released by the U.S. Cross Section Evaluation Working Group (CSEWG) in December 2006, contains data primarily for reactions with incident neutrons, protons, and photons on almost 400 isotopes, based on experimental data and theory predictions. The principal advances over the previous ENDF/B-VI library are the following: (1) New cross sections for U, Pu, Th, Np and Am actinide isotopes, with improved performance in integral validation criticality and neutron transmission benchmark tests; (2) More precise standard cross sections for neutron reactions on H, 6 Li, 10 B, Au and for 235,238 U fission, developed by a collaboration with the IAEA and the OECD/NEA Working Party on Evaluation Cooperation (WPEC); (3) Improved thermal neutron scattering; (4) An extensive set of neutron cross sections on fission products developed through a WPEC collaboration; (5) A large suite of photonuclear reactions; (6) Extension of many neutron- and proton-induced evaluations up to 150 MeV; (7) Many new light nucleus neutron and proton reactions; (8) Post-fission beta-delayed photon decay spectra; (9) New radioactive decay data; (10) New methods for uncertainties and covariances, together with covariance evaluations for some sample cases; and (11) New actinide fission energy deposition. The paper provides an overview of this library, consisting of 14 sublibraries in the same ENDF-6 format as the earlier ENDF/B-VI library. We describe each of the 14 sublibraries, focusing on neutron reactions. Extensive validation, using radiation transport codes to simulate measured critical assemblies, show major improvements: (a) The long-standing underprediction of low enriched uranium thermal assemblies is removed; (b) The 238 U and 208 Pb reflector biases in fast systems are largely removed; (c) ENDF/B-VI.8 good agreement for simulations of thermal high-enriched uranium assemblies is preserved; (d) The underprediction of fast criticality of 233,235 U and 239 Pu assemblies is removed; and (e) The intermediate spectrum critical assemblies are predicted more accurately. We anticipate that the new library will play an important role in nuclear technology applications, including transport simulations supporting national security, nonproliferation, advanced reactor and fuel cycle concepts, criticality safety, fusion, medicine, space applications, nuclear astrophysics, and nuclear physics facility design. The ENDF/B-VII.0 library is archived at the National Nuclear Data Center, BNL, and can be retrieved from www.nndc.bnl.gov .

J-PARC and new era of science

High Intensity Proton Accelerator Project promoted jointly by Japan Atomic Energy research Institute (JAERI) and High Energy Accelerator Research Organization (KEK), named as Japan Proton Accelerator Research Complex (J-PARC) was started on 1 April, 2001. The accelerator complex of J-PARC consists of three accelerators: 400 MeV Linac, 3 GeV rapid cycle synchrotron and 50 GeV synchrotron, and three major experimental facilities: Material & Life Science Facility, Nuclear & Particle Physics Facilities (Hadron and Neutrino Facilities) and Nuclear Transmutation Experiment Facility.

Accelerator Delay Stuns U.S. Scientists

Plans for a nuclear physics facility that would mimic stellar explosions have been pushed back 5 years, U.S. Secretary of Energy Samuel Bodman told Congress last week. (Read more.)

High intensity proton accelerator project in Japan (J-PARC)

The High Intensity Proton Accelerator Project, named as J-PARC, was started on 1 April 2001 at Tokai-site of JAERI. The accelerator complex of J-PARC consists of three accelerators: 400 MeV Linac, 3 GeV rapid cycle synchrotron and 50 GeV synchrotron; and four major experimental facilities: Material and Life Science Facility, Nuclear and Particle Physics Facility, Nuclear Transmutation Experiment Facility and Neutrino Facility. The outline of the J-PARC is presented with the current status of construction.

Fundamental symmetries and interactions --Some aspects

In the framework of nuclear physics and at nuclear physics facilities a large number of different experiments can be performed which render the possibility to investigate fundamental symmetries and interactions in nature. In particular, the precise measurements of properties of fundamental fermions, searches for new interactions in β-decays, and violations of discrete symmetries have a robust discovery potential for physics beyond standard theory. Precise measurements of fundamental constants can be carried out as well. Low energy experiments allow probing of New Physics models at mass scales far beyond the reach of present accelerators or such planned for the future in the domain of high energy physics and at which predicted new particles could be produced directly.