VII LATIN AMERICAN SYMPOSIUM ON NUCLEAR PHYSICS AND APPLICATIONS
947(2007); http://dx.doi.org/10.1063/1.2813840View Description Hide Description
We describe the Accelerator Mass Spectrometry (AMS) technique and two distinct applications of its use with to study environmental problems in Brazil, such as forest fires and climate changes in the Amazon region and archaeological studies on the early settlements in the Southeast Brazilian coast.
947(2007); http://dx.doi.org/10.1063/1.2813879View Description Hide Description
Over the past century basic nuclear science research has led to the use of radioactive isotopes into a wide variety of applications that touch our lives everyday. Some are obvious, such as isotopes for medical diagnostics and treatment. Others are less so, such as National/Global security issues. And some we take for granted, like the small amount of 241 Am that is in every smoke detector. At the beginning of this century, we are in a position where the prevalence and importance of some applications of nuclear science are pushing the basic nuclear science community for improved models and nuclear data. Yet, at the same time, the push by the basic nuclear science community to study nuclei that are farther and farther away from stability also offer new opportunities for many applications. This talk will look at several global security applications of nuclear science, summarizing current R&D and need for improved nuclear data It will also look at how applications of nuclear science, such as to medicine, will benefit from the push for more and more powerful radioactive ion beam facilities.
Accelerator‐Based Boron Neutron Capture Therapy and the Development of a Dedicated Tandem‐Electrostatic‐Quadrupole947(2007); http://dx.doi.org/10.1063/1.2813801View Description Hide Description
There is a generalized perception that the availability of suitable particle accelerators installed in hospitals, as neutron sources, may be crucial for the advancement of Boron Neutron Capture Therapy (BNCT). Progress on an ongoing project to develop a Tandem‐ElectroStatic‐Quadrupole (TESQ) accelerator for Accelerator‐Based (AB)‐BNCT is described here. The project goal is a machine capable of delivering 30 mA of 2.5 MeV protons to be used in conjunction with a neutron production target based on the reaction slightly beyond its resonance at 2.25 MeV. A folded tandem, with 1.25 MV terminal voltage, combined with an ESQ chain is being designed and constructed. A 30 mA proton beam of 2.5 MeV are the specifications needed to produce sufficiently intense and clean epithermal neutron beams, based on the reaction, to perform BNCT treatment for deep‐seated tumors in less than an hour. The first design and construction of an ESQ module is discussed and its electrostatic fields are investigated theoretically and experimentally. Also new beam transport calculations through the accelerator are presented.
947(2007); http://dx.doi.org/10.1063/1.2813813View Description Hide Description
A comprehensive and reliable description of nucleus‐nucleus interactions represents a crucial need in different interdisciplinary fields. In particular, hadrontherapy monitoring by means of in‐beam positron emission tomography (PET) requires, in addition to measuring, the capability of calculating the activity of ‐decaying nuclei produced in the irradiated tissue. For this purpose, in view of treatment monitoring at the Heidelberg Ion Therapy (HIT) facility, the transport and interaction Monte Carlo code FLUKA is a promising candidate. It is provided with the description of heavy ion reactions at intermediate and low energies by two specific event generators. In‐beam PET experiments performed at GSI for a few beam‐target combinations have been simulated and first comparisons between the measured and calculated ‐activity are available.
947(2007); http://dx.doi.org/10.1063/1.2813824View Description Hide Description
We develop a method, employing Compton peak standardization and the use of matrix‐matched spiked samples with Total Reflection X‐ray Fluorescence (TXRF), for the determination of platinum plasma concentrations of patients undergoing chemotherapy with Pt‐bearing drugs. Direct blood plasma analysis attains Pt detection limits of 70 ng/ml. Measurement results of prescribed drug doses are compared to achieved blood Pt concentrations indicating a lack of expected correlations. Direct analysis of Pt‐containing infused drugs from a variety of suppliers indicates cases of abnormal concentrations which raises quality control issues. We demonstrate the potential usefulness of the method for pharmacokinetic studies or for routine optimization and quality control of Pt chemotherapy treatments.
947(2007); http://dx.doi.org/10.1063/1.2813831View Description Hide Description
A compact and versatile Proton Recoil Telescope (PRT) detector has been realized to measure neutron energy spectra in the range from few to hundred MeV. The PRT is a position sensitive detector made by: an active multilayer segmented plastic scintillator as neutron to proton converter, two silicon strip detectors for proton energy and position measurement and a final thick CsI(T1) scintillator to measure the residual proton energy. The detector has been tested with the reaction at Laboratori Nazionali del Sud using a 40 MeV deuteron beam.
947(2007); http://dx.doi.org/10.1063/1.2813839View Description Hide Description
The objective of the work here was to assess the errors introduced by using 2D, few group homogenized cross sections to perform neutronic analysis of BWR problems with significant axial heterogeneities. The 3D method of characteristics code DeCART is used to generate 2‐group assembly homogenized cross sections first using a conventional 2D lattice model and then using a full 3D solution of the assembly. A single BWR fuel assembly model based on an advanced BWR lattice design is used with a typical void distribution applied to the fuel channel coolant. This model is validated against an MCNP model. A comparison of the cross sections is performed for the assembly homogenized planar cross sections from the DeCART 3D and DeCART 2D solutions.
Measurement of the Neutron Induced Fission Cross Section on Transuranic (TRU) Elements at the n_TOF Facility at CERN947(2007); http://dx.doi.org/10.1063/1.2813848View Description Hide Description
During the 2004 campaign, the n_TOF collaboration measured neutron fission cross sections for as well as the fission standards using a sealed Fission Ionization Chamber (FIC). The setup included a total of 16 targets and 18 electrodes mounted together in a 50‐cm length chamber, allowing the measurements of all isotopes at the same time, thus in the same experimental conditions. A brief description of the facility and of the detector setup will be presented followed by the preliminary results of the analysis of and from thermal energies up to some tenths of MeV.
947(2007); http://dx.doi.org/10.1063/1.2813871View Description Hide Description
Innovative nuclear technology applications have emerged in recent years and triggered an unprecedented interest of different communities of scientists worldwide, concerned by the multidisciplinary scientific, technical and engineering aspects of such applications. ADS (Accelerator Driven Systems, for the transmutation of highly radiotoxic nuclear waste), EA (Energy Amplifiers, for the production of energy), Spallation Neutron Sources (for multiple applications such as in Bio‐Sciences, Medicine, Material Science), Radioactive Ion Beams (of relevance for fundamental Nuclear Physics and Astrophysics, for applications in Medicine, amongst many others) are examples of applications that address a set of common multidisciplinary, leading edge and cross‐cutting issues and research topics. Other applications being considered for High‐Energy Physics purposes consist on facilities aiming at producing intense neutrino beams.
The sustainability of nuclear energy as an economically competitive, environmentally friend and proliferation resistant technology to meet mankind's growing energy demand has imposed in recent years the consideration of new (Generation IV) or non‐conventional types of nuclear reactors, operating with non‐standard coolants, higher‐energy neutron spectra, higher temperatures, amongst other issues. The safety and operational aspects of these nuclear energy systems share with the nuclear technology applications previously referred (ADS, EA, SNS, etc.) a set of common scientific and technical issues.
In this paper, the scientific, technical and engineering topics and issues of relevance for the implementation and deployment of some of the systems previously described are briefly presented. A set of selected major on‐going R&D programmes and experiments involving international collaborations of scientists and consortia of institutions are succinctly described.
947(2007); http://dx.doi.org/10.1063/1.2813872View Description Hide Description
A new Tagged Neutron Inspection System (TNIS) able to detect illicit materials such as explosives and narcotics in cargo containers has been developed within the EURopean Illicit TRAfficing Countermeasures Kit (EURITRACK) project. After the R&D phase, the inspection portal has been installed and commissioned at the Rijeka seaport in Croatia, where it has been operated in connection with the existing X‐ray scanner for a first two‐month demonstration campaign. Results obtained are presented and discussed in this paper.
947(2007); http://dx.doi.org/10.1063/1.2813873View Description Hide Description
Past experiments have shown that discrimination between between fissionable and non‐fissionable materials is possible using an interrogation technique that monitors for high energy prompt fission neutrons. Several recent upgrades have been made to the neutron time of flight spectrometer at the Idaho Accelerator Center with the intent of increasing neutron detection sensitivity, allowing for system use in nonproliferation and security applications.
947(2007); http://dx.doi.org/10.1063/1.2813874View Description Hide Description
Five years operation of a compact cyclotron installed at PET‐CT facility in Caracas, Venezuela is given. Production rate of labeled FDG, operation and radiation monitoring experience are included. We conclude that CT‐PET is the most effective technique for patient diagnosis.
947(2007); http://dx.doi.org/10.1063/1.2813875View Description Hide Description
The Neutron Backscattering technique is tested when performing the task of localizing hydrogenated explosives hidden in soil. Detector system, landmine, soil and neutron source are simulated with Geant4 in order to obtain the number of neutrons detected when several parameters like mine composition, relative position mine‐source and soil moisture are varied.
947(2007); http://dx.doi.org/10.1063/1.2813876View Description Hide Description
The determination of the pattern of hadronic resonances as predicted by Quantum Chromodynamics requires the use of non‐perturbative techniques. Lattice QCD has emerged as the dominant tool for such calculations, and has produced many QCD predictions which can be directly compared to experiment. The concepts underlying lattice QCD are outlined, methods for calculating excited states are discussed, and results from an exploratory Nucleon and Delta baryon spectrum study are presented.
947(2007); http://dx.doi.org/10.1063/1.2813877View Description Hide Description
The photoproduction of vector mesons on various nuclei has been studied using the CLAS detector at Jefferson Laboratory. The vector mesons, ρ, ω, and φ, are observed via their decay to in order to reduce the effects of final state interactions in the nucleus. Of particular interest are possible in‐medium effects on the properties of the ρ meson. The ρ mass spectrum is extracted from the data on various nuclei, C, Fe, and Ti. We observe no significant mass shift and some broadening consistent with expected collisional broadening for the ρ meson.
947(2007); http://dx.doi.org/10.1063/1.2813878View Description Hide Description
Nucleons are complex systems of confined quarks and exhibit characteristic spectra of excited states. Highly excited nucleon states are sensitive to details of quark confinement which is poorly understood within Quantum Chromodynamics (QCD), the fundamental theory of strong interactions. Thus, measurements of excited states and the corresponding determination of their properties are needed to come to a better understanding of how confinement works in nucleons. However, the excited states of the nucleon cannot simply be inferred from cleanly separated spectral lines. Quite the contrary, a spectral analysis in nucleon resonance physics is challenging because of the fact that the resonances are broadly overlapping states which decay into a multitude of final states involving mesons and baryons. To provide a consistent and complete picture of an individual nucleon resonance, the various possible production and decay channels must be treated in a multichannel framework that permits separating resonance from background contributions. Very often, resonances reveal themselves more clearly through interference with dominant amplitudes. These interference terms can be isolated via polarization observables. The current CLAS effort is to utilize highly‐polarized hydrogen and deuterium targets as well as polarized photon beams toward a complete measurement of a large number of reaction channels.
947(2007); http://dx.doi.org/10.1063/1.2813786View Description Hide Description
The nuclear incoherent photoproduction cross section from is evaluated at forward angles in the 4.0 to 6.0 GeV energy range using the multicollisional intranuclear cascade model MCMC. The model incorporates some improvements in comparison with previous versions associated with the momentum distribution (MD) for light nuclei—extracted from the available data—as well as the evaluation of the shadowing effects during the photo‐nucleus interaction. The final results of the single and double differential cross sections at forward angles are very sensitive to the MD parameterizations due to the Pauli principle, which largely suppresses the cross sections for low momentum transfer. The attenuation of the nuclear cross section due to pion—nucleus final state interactions is approximately 40% (without nuclear shadowing), which is in nice agreement with the predictions from the Glauber model. The single and double differential cross sections are presented for possible applications for the interpretation of the inelastic background in the PrimEx experiment at the Jefferson Laboratory.
947(2007); http://dx.doi.org/10.1063/1.2813787View Description Hide Description
The STAR experiment at the Relativistic Heavy‐Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) is carrying out a spin physics program colliding transverse or longitudinal polarized proton beams at to gain a deeper insight into the spin structure and dynamics of the proton. These studies provide fundamental tests of Quantum Chromodynamics (QCD).
One of the main objectives of the STAR spin physics program is the determination of the polarized gluon distribution function through a measurement of the longitudinal double‐spin asymmetry, for various processes. Recent results will be shown on the measurement of for inclusive jet production, neutral pion production and charged pion production at
947(2007); http://dx.doi.org/10.1063/1.2813788View Description Hide Description
The Large Hadron Collider (LHC) at CERN will start running 2008 producing proton‐proton collisions with a center‐of‐mass energy of 14 TeV. Four large experiments will operate together with this accelerator: ALICE, ATLAS, CMS and LHCb. The main scientific goal of this project is to understand in detail the mechanism for electro‐weak symmetry breaking and to search for physics beyond the standard model of particles. ATLAS and CMS are general purpose detectors designed for search and discovery of new physics, and optimized to search for Higgs and signals of supersymmetric matter (SUSY). In this paper the main features of the CMS detector will be presented and its potential for Higgs and SUSY discoveries will be discussed.