Sample records for slow neutron capture

  1. Neutron capture therapies

    DOEpatents

    Yanch, Jacquelyn C. (Cambridge, MA); Shefer, Ruth E. (Newton, MA); Klinkowstein, Robert E. (Winchester, MA)

    1999-01-01

    In one embodiment there is provided an application of the .sup.10 B(n,.alpha.).sup.7 Li nuclear reaction or other neutron capture reactions for the treatment of rheumatoid arthritis. This application, called Boron Neutron Capture Synovectomy (BNCS), requires substantially altered demands on neutron beam design than for instance treatment of deep seated tumors. Considerations for neutron beam design for the treatment of arthritic joints via BNCS are provided for, and comparisons with the design requirements for Boron Neutron Capture Therapy (BNCT) of tumors are made. In addition, exemplary moderator/reflector assemblies are provided which produce intense, high-quality neutron beams based on (p,n) accelerator-based reactions. In another embodiment there is provided the use of deuteron-based charged particle reactions to be used as sources for epithermal or thermal neutron beams for neutron capture therapies. Many d,n reactions (e.g. using deuterium, tritium or beryllium targets) are very prolific at relatively low deuteron energies.

  2. Neutron capture reactions in astrophysics

    NASA Astrophysics Data System (ADS)

    Käppeler, F.

    1985-01-01

    About 2/3 of the chemical elements in nature were formed in neutron capture reactions. During the life of a star there are certain evolutionary stages where neutrons are available to build up the elements beyond iron which cannot be synthesized by charged particle reactions. The observed abundance pattern allows to distinguish a rapid and a slow neutron capture process (r- and s-process). The r-process taking place far from the valley of stability is difficult to investigate because of the required extrapolation of nuclear properties to extreme neutron rich nuclei. The s-process, on the other hand, proceeds along the valley of stability. Therefore, the involved isotopes are accessible to laboratory measurements. This information allows for quantitative calculation of s-process abundances and other parameters which represent constraints for stellar models. Two examples are outlined: (i) the s-process branching at A=147, 148 yields a rather accurate value for the neutron density. (ii) Comparison of s-process abundances with observations of stellar atmospheres are particularly interesting for the unstable isotopes 93Zr, 99Tc and 147Pm. Their deficiency with respect to stable neighbors may yield estimates for the transport time from the stellar interior to the surface.

  3. Neutron Capture Reactions for Stockpile Stewardship and Basic Science

    Microsoft Academic Search

    W Parker; U Agvaanluvsan; J Becker; P Wilk; C Wu; T Bredeweg; A Couture; R Haight; M Jandel; J ODonnell; R Reifarth; R Rundberg; J Ullmann; D Vieira; J Wouters; S Sheets; G Mitchell; F Becvar; M Krticka

    2007-01-01

    The capture process is a nuclear reaction in which a target atom captures an incident projectile, e.g. a neutron. The excited-state compound nucleus de-excites by emitting photons. This process creates an atom that has one more neutron than the target atom, so it is a different isotope of the same element. With low energy (slow) neutron projectiles, capture is the

  4. Iodine neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Ahmed, Kazi Fariduddin

    A new technique, Iodine Neutron Capture Therapy (INCT) is proposed to treat hyperthyroidism in people. Present thyroid therapies, surgical removal and 131I treatment, result in hypothyroidism and, for 131I, involve protracted treatment times and excessive whole-body radiation doses. The new technique involves using a low energy neutron beam to convert a fraction of the natural iodine stored in the thyroid to radioactive 128I, which has a 24-minute half-life and decays by emitting 2.12-MeV beta particles. The beta particles are absorbed in and damage some thyroid tissue cells and consequently reduce the production and release of thyroid hormones to the blood stream. Treatment times and whole-body radiation doses are thus reduced substantially. This dissertation addresses the first of the several steps needed to obtain medical profession acceptance and regulatory approval to implement this therapy. As with other such programs, initial feasibility is established by performing experiments on suitable small mammals. Laboratory rats were used and their thyroids were exposed to the beta particles coming from small encapsulated amounts of 128I. Masses of 89.0 mg reagent-grade elemental iodine crystals have been activated in the ISU AGN-201 reactor to provide 0.033 mBq of 128I. This activity delivers 0.2 Gy to the thyroid gland of 300-g male rats having fresh thyroid tissue masses of ˜20 mg. Larger iodine masses are used to provide greater doses. The activated iodine is encapsulated to form a thin (0.16 cm 2/mg) patch that is then applied directly to the surgically exposed thyroid of an anesthetized rat. Direct neutron irradiation of a rat's thyroid was not possible due to its small size. Direct in-vivo exposure of the thyroid of the rat to the emitted radiation from 128I is allowed to continue for 2.5 hours (6 half-lives). Pre- and post-exposure blood samples are taken to quantify thyroid hormone levels. The serum T4 concentration is measured by radioimmunoassay at different times after exposure as an indicator of thyroid function. Cell damage is assessed by postmortem histopathologic examination. The intent of this endeavor is to relate radiation dose, T4 concentration in the blood stream and cellular damage. This information will help better understand the dose response relationship of thyroid cells exposed to ionizing radiation.

  5. Neutron capture measurements on 62Ni, 63Ni and 197Au and their relevance for stellar nucleosynthesis

    Microsoft Academic Search

    Claudia Lederer

    2012-01-01

    Neutron capture reactions in stars are responsible for forming about 99% of the elemental abundances heavier than Fe. Two processes contribute about equally to the overall abundance pattern: the slow neutron capture process (s process) where neutron densities are small and therefore radioactive decay is generally faster than subsequent neutron capture on radionuclides, and the rapid neutron capture process (r

  6. Neutron capture reactions in astrophysics

    SciTech Connect

    Kaeppeler, F.

    1985-01-15

    About 2/3 of the chemical elements in nature were formed in neutron capture reactions. During the life of a star there are certain evolutionary stages where neutrons are available to build up the elements beyond iron which cannot be synthesized by charged particle reactions.

  7. Accelerators and Neutron Capture Therapy

    NASA Astrophysics Data System (ADS)

    Burlon, A. A.; Kreiner, A. J.; Valda, A.

    2002-08-01

    Within the frame of Accelerator Based Boron Neutron Capture Therapy (AB-BNCT), the 7Li (p,n) 7Be reaction, relatively near its energy threshold is one of the most promising, due to its high yield and low neutron energy. In this work a thick LiF target irradiated with a proton beam was studied as a neutron source. The 1.88-2.0 MeV proton beam was produced by the tandem accelerator TANDAR at CNEA's facilities in Buenos Aires. A water-filled phantom, containing a boron sample was irradiated with the resulting neutron flux. The 10B(n,??)7Li boron neutron capture reaction produces a 0.478 MeV gamma ray in 94% of the cases. The neutron yield was measured through the detection of this gamma ray using a hyperpure germanium detector with an anti-Compton shield. In addition, the thermal neutron flux was evaluated at different depths inside the phantom using bare and Cd-covered gold foils. A maximum neutron thermal flux of 1.4×108 cm-2s-1mA-1 was obtained at 4.2 cm from the phantom surface. In order to optimize the design of the neutron production target and the beam shaping assembly extensive Monte Carlo Neutron and Photon (MCNP) simulations have been performed. Neutron fields from a thick LiF and a Li metal target (with both a D2O-graphite and a Al/AlF3-graphite moderator/reflector assembly) were evaluated along the centerline of a head and a whole body phantom. Simulations were carried out for 1.89, 2.0 and 2.3 MeV proton beams. The results show that it is more advantageous to irradiate the target with 2.3 MeV near-resonance protons, instead of very near threshold, because of the higher neutron yield at this energy. On the other hand, the Al/AlF3-graphite exhibits a more efficient performance than D2O in terms of tumor to maximum healthy tissue dose ratio. Treatment times of less than 15 min and tumor control probabilities larger than 98% are obtained for a 50 mA, 2.3 MeV proton beam. The alternative neutron-producing reaction 13C(d,n) is also briefly reviewed. A proposal is made to construct an electrostatic, 2.5 MeV, 50 mA proton accelerator suitable for hospital use. A combination of a Tandem and an Electrostatic Quadrupole is considered to be the best option.

  8. [Epithermal neutron capture therapy

    SciTech Connect

    Not Available

    1993-01-01

    Development of a 4 mA, 2.5 MeV Tandem Cascade Accelerator (TCA) for the production of neutrons via the [sup 7]Li(p,n)[sup 7]Be nuclear reaction is currently nearing completion at SRL. The TCA is a tandem electrostatic accelerator which uses a high current negative ion source in conjunction with a high current solid state cascade multiplier power supply to provide a compact, low cost, proton accelerator capable of supplying multi-milliampere currents at several million electron volts. The inherent simplicity and flexibility of this accelerator provide several features which are desirable for laboratory and clinical applications requiring the generation of high neutron fluxes. The beam aperture of the accelerating tube is large so that critical focusing and alignment of the beam is not required. Both the ion beam source and target are at ground potential during operation. This configuration allows different moderator geometries to be incorporated easily into the target design. A high degree of compactness is achieved by a patented SRL design which allows the power supply to be mounted directly onto the accelerating column thereby eliminating the need for an external power supply chassis. The TCA is unique in its capability to accelerate multi-milliampere ion beams to 2.5 MeV. A direct result of the patented high current solid-state power supply developed by SRL and the use of a high current, high brightness multicusp negative ion source. The TCA requires no RF or magnetic fields which greatly reduces the system weight, power dissipation and heat load on auxiliary systems when compared with radiofrequency quadrupole (RFQ) or cyclotron-type accelerators. Delivery of current is continuous, rather than pulsed as in an RFQ, which reduces the peak thermal and mechanical stresses on the target and simplifies target design. The accelerator weighs less than 2,000 lbs., has an overall length of approximately 2.6 m, and requires approximately 25 kW of electrical power.

  9. Improved neutron sources for neutron capture enhanced fast neutron therapy

    Microsoft Academic Search

    D. W. Nigg; C. A. Wemple; R. Risler; J. K. Hartwell; Y. D. Harker; G. E. Laramore

    2000-01-01

    Fast neutron radiotherapy (FNT) can be combined with boron neutron capture therapy (BNCT). The selective incremental absorbed dose in the target volume that is thus obtained may be sufficient to produce a significant improvement in tumor control probability in some cases. Potential applications include certain non-small-cell lung tumors; head and neck tumors; prostate tumors; and possibly also glioblastoma multiform, an

  10. Accelerator neutron source for boron neutron capture therapy

    Microsoft Academic Search

    C. K. Wang; T. E. Blue; J. W. Blue; R. A. Gahbauer

    1987-01-01

    If boron neutron capture therapy (BNCT) is to be widely used to treat patients with brain tumors, then a hospital-based neutron source must be developed. Accelerator neutron sources for BNCT have been proposed as alternatives to nuclear reactor beams. The ideal neutron source for BNCT is a monoenergetic neutron beam with a neutron energy that is above thermal energies but

  11. Radioactivity induced by neutrons: Enrico Fermi and a thermodynamic approach to radiative capture

    Microsoft Academic Search

    Alberto de Gregorio

    2006-01-01

    When Fermi learned that slow neutrons are much more effective than fast ones in inducing radioactivity, he explained this phenomenon by mentioning the well-known scattering cross section between neutrons and protons. At this early stage, he did not refer to the capture cross section by target nuclei. At the same time a thermodynamic approach to neutron-proton capture was being discussed

  12. Neutron Capture Reactions for Stockpile Stewardship and Basic Science

    SciTech Connect

    Parker, W; Agvaanluvsan, U; Becker, J; Wilk, P; Wu, C; Bredeweg, T; Couture, A; Haight, R; Jandel, M; O'Donnell, J; Reifarth, R; Rundberg, R; Ullmann, J; Vieira, D; Wouters, J; Sheets, S; Mitchell, G; Becvar, F; Krticka, M

    2007-08-04

    The capture process is a nuclear reaction in which a target atom captures an incident projectile, e.g. a neutron. The excited-state compound nucleus de-excites by emitting photons. This process creates an atom that has one more neutron than the target atom, so it is a different isotope of the same element. With low energy (slow) neutron projectiles, capture is the dominant reaction, other than elastic scattering. However, with very heavy nuclei, fission competes with capture as a method of de-excitation of the compound nucleus. With higher energy (faster) incident neutrons, additional reactions are also possible, such as emission of protons or emission of multiple neutrons. The probability of a particular reaction occurring (such as capture) is referred to as the cross section for that reaction. Cross sections are very dependent on the incoming neutron's energy. Capture reactions can be studied either using monoenergetic neutron sources or 'white' neutron sources. A 'white' neutron source has a wide range of neutron energies in one neutron beam. The advantage to the white neutron source is that it allows the study of cross sections as they depend on neutron energies. The Los Alamos Neutron Science Center, located at Los Alamos National Laboratory, provides an intense white neutron source. Neutrons there are created by a high-energy proton beam from a linear accelerator striking a heavy metal (tungsten) target. The neutrons range in energy from subthermal up to very fast - over 100 MeV in energy. Low-energy neutron reaction cross sections fluctuate dramatically from one target to another, and they are very difficult to predict by theoretical modeling. The cross sections for particular capture reactions are important for defense sciences, advanced reactor concepts, transmutation of radioactive wastes and nuclear astrophysics. We now have a strong collaboration between Lawrence Livermore National Laboratory, Los Alamos National Laboratory, North Carolina State University and Charles University in Prague. In this paper, we report neutron capture studies that are of particular interest to Lawrence Livermore National Laboratory. In addition to determining neutron capture cross sections, we are also interested in the nuclear properties of the excited state compound nuclei created in the capture reactions. One model that describes the behavior of the nucleus is the statistical model. Our statistical studies included measuring the photon strength function, resonance parameters, level density and gamma-ray ({gamma}-ray) cascade multiplicity. The DANCE array allows the separation of cascades by the number of transitions (multiplicity) in the cascade, and this makes it possible to study detailed properties of the statistical cascade such as the relationship between multiplicity and energy distributions. The work reported here includes reaction on molybdenum targets, europium targets, gadolinium targets and the first americium-242m target. Our goal is to improve the accuracy and provide new measurements for stable and radioactive targets. We are especially interested in energy-dependent neutron capture cross sections. In all of our experiments, the photons emitted in the capture reactions are gamma rays, and they are detected by the barium fluoride crystal array named the Detector for Advanced Neutron Capture Experiments (DANCE) shown in Fig. 1. The detector array is made of 160 crystals arranged in a sphere around the target. There are four different crystal shapes, each of which covers an equal solid angle. This array was specifically designed to measure neutron capture cross sections with targets that were milligram sized or smaller, including radioactive targets. The barium fluoride crystals are scintillation (light generating) detectors with very fast response time, and are therefore suitable for high count rate experiments. Actual neutron capture events must be reliably distinguished from background {gamma}-rays, which are always present in neutron induced reactions. To reduce the background of scattered neutrons, a lithium hyd

  13. Workshop on neutron capture therapy

    SciTech Connect

    Fairchild, R.G.; Bond, V.P. (eds.)

    1986-01-01

    Potentially optimal conditions for Neutron Capture Therapy (NCT) may soon be in hand due to the anticipated development of band-pass filtered beams relatively free of fast neutron contaminations, and of broadly applicable biomolecules for boron transport such as porphyrins and monoclonal antibodies. Consequently, a number of groups in the US are now devoting their efforts to exploring NCT for clinical application. The purpose of this Workshop was to bring these groups together to exchange views on significant problems of mutual interest, and to assure a unified and effective approach to the solutions. Several areas of preclinical investigation were deemed to be necessary before it would be possible to initiate clinical studies. As neither the monomer nor the dimer of sulfhydryl boron hydride is unequivocally preferable at this time, studies on both compounds should be continued until one is proven superior.

  14. Improved neutron sources for neutron capture enhanced fast neutron therapy

    SciTech Connect

    Nigg, D.W.; Wemple, C.A.; Risler, R.; Hartwell, J.K.; Harker, Y.D.; Laramore, G.E.

    2000-07-01

    Fast neutron radiotherapy (FNT) can be combined with boron neutron capture therapy (BNCT). The selective incremental absorbed dose in the target volume that is thus obtained may be sufficient to produce a significant improvement in tumor control probability in some cases. Potential applications include certain non-small-cell lung tumors; head and neck tumors; prostate tumors; and possibly also glioblastoma multiform, an extremely refractory type of primary brain tumor. A class of modified neutron production targets has been developed to provide improved performance of the cyclotron-based clinical FNT facility at the University of Washington (UW) Medical Center for applications involving BNCT-enhanced FNT. The new targets produce neutron beams that feature essentially the same fast neutron physical depth-dose performance as the current UW system but with an increased fraction of BNCT enhancement.

  15. Neutron capture therapy for melanoma

    SciTech Connect

    Coderre, J.A.; Glass, J.D.; Micca, P.; Fairchild, R.G.

    1988-01-01

    The development of boron-containing compounds which localize selectively in tumor may require a tumor-by-tumor type of approach that exploits any metabolic pathways unique to the particular type of tumor. Melanin-producing melanomas actively transport and metabolize aromatic amino acids for use as precursors in the synthesis of the pigment melanin. It has been shown that the boron-containing amino acid analog p-borono-phenylalanine (BPA) is selectively accumulated in melanoma tissue, producing boron concentrations in tumor that are within the range estimated to be necessary for successful boron neutron capture therapy (BNCT). We report here the results of therapy experiments carried out at the Brookhaven Medical Research Reactor (BMRR). 21 refs., 5 figs., 3 tabs.

  16. Boron Neutron Capture Therapy for Cancer

    Microsoft Academic Search

    Rolf F. Barth; Albert H. Soloway; Ralph G. Fairchild

    1990-01-01

    Boron neutron capture therapy (BNCT) bring together two components that when kept separate have only minor effects on normal cells. The first component is a stable isotope of boron (boron 10) that can be concentrated in tumor cells. The second is a beam of low-energy neutrons that produces short-range radiation when absorbed, or captured, by the boron. The combination of

  17. Neutron capture reaction rates for stellar nucleosynthesis

    SciTech Connect

    Mengoni, A. [Department of Nuclear Sciences and Applications, Division of Physical and Chemical Sciences, Nuclear Data Section, International Atomic Energy Agency, A-1400 Wagramer Strasse 5, Vienna (Austria)

    2006-03-13

    A short summary of the three fundamental neutron capture reaction processes of interest in stellar nucleosynthesis is presented. Three examples of actual situations in which the capture reaction proceeds through one of these processes are identified and an overview of the experimental data as well as of the model calculations used in the determination of the capture rates are presented.

  18. Computer simulation of neutron capture therapy

    E-print Network

    Olson, Arne Peter

    1967-01-01

    Analytical methods are developed to simulate on a large digital computer the production and use of reactor neutron beams f or boron capture therapy of brain tumors. The simulation accounts for radiation dose distributions ...

  19. Neutron-capture therapy with ultra-cold neutrons

    Microsoft Academic Search

    S. S. Arzumanov; L. N. Bondarenko; V. A. Zagryadskii; D. V. Markovskii; V. I. Morozov; A. N. Strepetov; D. Yu. Chuvilin

    2010-01-01

    The status of neutron-capture therapy of malignant tumors and its problems – damage to healthy tissue as a result of neutron\\u000a transport to the irradiation location and presence in the therapeutic beam of a background consisting of ? rays and fast neutrons\\u000a – are presented. To solve these problems, the authors have proposed using ultracold neutrons with energy less than

  20. Neutron capture therapy research in Australia.

    PubMed

    Allen, B J

    1989-01-01

    Neutron capture therapy research in Australia has continued to grow since the first Australia-Japan workshop in April, 1986. The support base has broadened and the wide range of contributing laboratories includes universities, research institutes, and hospitals. Considerable progress has been made in boron chemistry--an accurate boron assay technique has been developed, boron analogues of chlorpromazine and thiouracil have been synthesised or nearly so, and decaborane conjugation with monoclonal antibodies has been achieved to the required loadings. In vitro cell survival experiments are proceeding in the Moata reactor using human melanoma and mouse cell lines incubated with enriched boronophenylalanine and boron tetraphenyl porphyrins. Electron microscopy examination of radiation damaged morphology shows considerable differences between cell lines. Progress with the nude mouse human melanoma model has been slow because of the lack of a reliable in vivo melanotic melanoma line, and the B16 mouse line is found to be more efficacious. Tailored beam calculations for the 10 MW HIFAR reactor indicate the difficulty of obtaining a suitable therapeutic beam because of the generated gamma dose in the beam filters. A new approach to NCT utilises the enormous cross section of 157Gd and the induced-Auger effect which has been shown to cause double strand breaks in circular DNA. PMID:2678079

  1. Biological dosimetry of neutron beams for neutron capture therapies

    E-print Network

    White, Susan Marie, 1973-

    2001-01-01

    Boron neutron capture therapies using the 10B(n,a)7Li reaction have been proposed as treatments for glioblastoma multiforme, metastatic melanoma, rheumatoid arthritis, and other debilitating conditions. This thesis presents ...

  2. Accelerator neutron source for boron neutron capture therapy

    SciTech Connect

    Wang, C.K.; Blue, T.E.; Blue, J.W.; Gahbauer, R.A.

    1987-01-01

    If boron neutron capture therapy (BNCT) is to be widely used to treat patients with brain tumors, then a hospital-based neutron source must be developed. Accelerator neutron sources for BNCT have been proposed as alternatives to nuclear reactor beams. The ideal neutron source for BNCT is a monoenergetic neutron beam with a neutron energy that is above thermal energies but below approx. 10 keV. The optimum neutron energy is currently being studied. The purpose of this paper is to report the results of a Monte Carlo analysis of the performance of an accelerator neutron source for the treatment of brain tumors by BNCT. The proton beam is identical. Thicknesses of moderators are identified that yield neutron energy spectra which produce within a head phantom distributions of absorbed dose approaching the distributions that would be attained with the above-mentioned ideal spectra.

  3. Positron on Neutron capture reaction, radiative corrections and neutron EDM

    E-print Network

    Mikhail Khankhasayev; Carol Scarlett

    2013-05-28

    This paper presents an analysis of the positron capture by a neutron reaction, which is just the inverse of the well-known neutrino capture by a proton reaction. The effect of the QED radiative corrections is investigated. In particular, the analysis considers the effects of treating the neutron as a composite object that can have an electric dipole moment (nEDM). For the case of unpolarized hadrons the effects of a nEDM appear to vanish.

  4. Radioactivity induced by neutrons: Enrico Fermi and a thermodynamic approach to radiative capture

    NASA Astrophysics Data System (ADS)

    De Gregorio, Alberto

    2006-07-01

    When Fermi learned that slow neutrons are much more effective than fast ones in inducing radioactivity, he explained this phenomenon by mentioning the well-known scattering cross section between neutrons and protons. At this early stage, he did not refer to the capture cross section by target nuclei. At the same time a thermodynamic approach to neutron-proton capture was being discussed by physicists: neutron capture was interpretated as the reverse of deuteron photodissociation and detailed balance among neutrons, protons, deuterons, and radiation was invoked. This thermodynamic approach might underlie Fermi's early explanation of the great efficiency of slow neutrons. Fermi repeatedly used a thermodynamic approach that had been used in describing some of the physical properties of conductors by Richardson and had been influential in Fermi's youth.

  5. Radiation Field for Fission Neutron Enhanced Boron Neutron Capture Therapy Employing Fast Neutron Source Reactor “YAYOI”

    Microsoft Academic Search

    Hiroaki WAKABAYASHI; Kozi YOSHII; Norihiko SASUGA; Hideharu YANAGI

    1982-01-01

    Boron Neutron Capture Therapy (BNCT) of a localized tumor needs a sufficient thermal neutron flux at the tumor. A surgical operation including ennucleation of the main part of tumor is required for the case of thermal neutron beam from a thermal reactor because of the rapid decrease of the neutron flux in the tissue. Intermediate neutrons with little fast neutron

  6. An accelerator neutron source for BNCT (Boron Neutron Capture Therapy)

    Microsoft Academic Search

    Blue

    1990-01-01

    The objectives of this proposal are twofold. One objective is to design and test (using the OSU Van de Graaff accelerator) a moderator assembly for a thermal neutron source for the treatment of superficial tumors by Boron Neutron Capture Therapy (BNCT). We will identify the current of 2.5 MeV protons which is necessary to treat a patient in less than

  7. Approach to magnetic neutron capture therapy

    SciTech Connect

    Kuznetsov, Anatoly A. [Institute of Biochemical Physics of RAS, Moscow (Russian Federation)]. E-mail: spod@sky.chph.ras.ru; Podoynitsyn, Sergey N. [Institute of Biochemical Physics of RAS, Moscow (Russian Federation); Filippov, Victor I. [Institute of Biochemical Physics of RAS, Moscow (Russian Federation); Komissarova, Lubov Kh. [Institute of Biochemical Physics of RAS, Moscow (Russian Federation); Kuznetsov, Oleg A. [Institute of Biochemical Physics of RAS, Moscow (Russian Federation)

    2005-11-01

    Purpose: The method of magnetic neutron capture therapy can be described as a combination of two methods: magnetic localization of drugs using magnetically targeted carriers and neutron capture therapy itself. Methods and Materials: In this work, we produced and tested two types of particles for such therapy. Composite ultradispersed ferro-carbon (Fe-C) and iron-boron (Fe-B) particles were formed from vapors of respective materials. Results: Two-component ultradispersed particles, containing Fe and C, were tested as magnetic adsorbent of L-boronophenylalanine and borax and were shown that borax sorption could be effective for creation of high concentration of boron atoms in the area of tumor. Kinetics of boron release into the physiologic solution demonstrate that ultradispersed Fe-B (10%) could be applied for an effective magnetic neutron capture therapy. Conclusion: Both types of the particles have high magnetization and magnetic homogeneity, allow to form stable magnetic suspensions, and have low toxicity.

  8. Dynamical Capture Binary Neutron Star Mergers

    NASA Astrophysics Data System (ADS)

    East, William E.; Pretorius, Frans

    2012-11-01

    We study dynamical capture binary neutron star mergers as may arise in dense stellar regions such as globular clusters. Using general-relativistic hydrodynamics, we find that these mergers can result in the prompt collapse to a black hole or in the formation of a hypermassive neutron star, depending not only on the neutron star equation of state but also on impact parameter. We also find that these mergers can produce accretion disks of up to a tenth of a solar mass and unbound ejected material of up to a few percent of a solar mass. We comment on the gravitational radiation and electromagnetic transients that these sources may produce.

  9. Neutron Capture Nucleosynthesis in Early Galactic Environments #

    E-print Network

    Cowan, John

    in the close agreement of these two stellar patterns (which rep­ resent the nucleosynthesis products ofNeutron Capture Nucleosynthesis in Early Galactic Environments # James W. Truran 1 , John J. Cowan we can extract useful clues to and constraints upon the star formation and nucleosynthesis history

  10. Neutron transmission and capture of 241Am

    NASA Astrophysics Data System (ADS)

    Lampoudis, C.; Kopecky, S.; Plompen, A.; Schillebeeckx, P.; Wynants, R.; Gunsing, F.; Sage, C.; Bouland, O.; Noguere, G.

    2013-03-01

    A set of neutron transmission and capture experiments based on the Time Of Flight (TOF) technique, were performed in order to determine the 241Am capture cross section in the energy range from 0.01 eV to 1 keV. The GELINA facility of the Institute for Reference Materials and Measurements (IRMM) served as the neutron source. A pair of C6D6 liquid scintillators was used to register the prompt gamma rays emerging from the americium sample, while a Li-glass detector was used in the transmission setup. Results from the capture and transmission data acquired are consistent with each other, but appear to be inconsistent with the evaluated data files. Resonance parameters have been derived for the data up to the energy of 100 eV.

  11. Review of the fundamentals of the neutron-capture reaction

    SciTech Connect

    Chrien, R.E.

    1982-01-01

    Fifty years of research into the nature of the radiative capture reaction mechanisms is briefly summarized. A variety of such mechanisms is exploited to explain neutron capture over nine decades of neutron energy.

  12. Present status of boron neutron capture therapy.

    PubMed

    Carlsson, J; Sjöberg, S; Larsson, B S

    1992-01-01

    The neutron capture reaction 10B(1n,4He)7Li produces two energetic particles, 4He2+ and 7Li3+ that are strongly cell toxic. Due to the short range of these nuclear fragments (5-9 microns) mainly those cells that have bound or internalized a 10B-containing substance are growth-inactivated. The most critical and difficult step in an efficient boron neutron capture therapy (BNCT) is the tumour targeting. It is today possible to synthesize a large number of boron compounds and conjugate them to tumour-seeking macromolecules, such as monoclonal antibodies or different polypeptides. The boron-containing substances presently considered for therapy are sulfhydryl boron hydride (BSH) and boron-phenylalanine, (BPA) for the treatment of gliomas and malignant melanomas respectively. Other boronated compounds considered are ligands for receptor-amplified tumour cells, antibodies for tumour cells with specific antigens and thioureas for treatment of melanotic melanomas. The required boron concentration is given by the relative dose due to neutron capture in 10B and that of the competing capture reactions in nitrogen and hydrogen. Capture in nitrogen produces protons with a range of about 10-11 microns and this gives a radiation dose to all cells in the neutron activated area. Calculations show that the local concentration of 10B near the critical radiation target, DNA, must be higher than 10 ppm (10 micrograms/g). Increased emphasis will be put on the development of combinations of treatments that fulfil the requirements for attacking the microscopic spread of the tumour. PMID:1290630

  13. An accelerator neutron source for BNCT (Boron Neutron Capture Therapy)

    SciTech Connect

    Blue, T.E.

    1990-03-01

    The objectives of this proposal are twofold. One objective is to design and test (using the OSU Van de Graaff accelerator) a moderator assembly for a thermal neutron source for the treatment of superficial tumors by Boron Neutron Capture Therapy (BNCT). We will identify the current of 2.5 MeV protons which is necessary to treat a patient in less than one hour. Our second objective is to design and thermally test a target for our thermal and epithermal source of neutrons for BNCT. Our work to date in fulfilling these project goals is described in this document. 11 refs., 4 figs., 1 tab.

  14. Preparation of radioactive rare earth targets for neutron capture study

    SciTech Connect

    Miller, G. G. (Geoffrey G.); Rogers, P. S. Z. (Pamela S. Z.); Palmer, P. D. (Phillip D.); Dry, D. E. (Donald E.); Rundberg, R. S. (Robert S.); Fowler, Malcolm M.; Wilhelmy, J. B. (Jerry B.)

    2002-01-01

    The understanding of thc details of nucleosynthesis in stars remains a great challenge. Though the basic mechanisms governing the processes have been known since the pioneering work of Burbidge, Burbidge, Fowler and Hoyle (l), we are now evolving into a condition where we can ask more specific questions. Of particular interest are the dynamics of the s ('slow') process. In this process the general condition is one in which sequential neutron captures occur at time scales long compared with the beta decay half lives of the capturing nuclides. The nucleosynthesis period for C or Ne burning stellar shells is believed to be in the year to few year time frame (2). This means that radionuclides with similar half lives to this burning period serve as 'branch point' nuclides. That is, there will be a competition between a capture to the next heavier isotope and a beta decay to the element of nexl higher atomic number. By understanding the abundances of these competing reactions we can learn about the dynamics of the nucleosynthesis process in the stellar medium. Crucial to this understanding is that we have a knowledge of the underlying neutron reaction cross sections on these unstable nuclides in the relevant stellar energy regions (neutrons of 0.1-100 KeV). Tm (1.9 years) and ls'Sm (90 ycws) have decay properties that permit their handling in an open fume hood. These Iwo were therefore selected to be the first radionuclides for neutron capture study in what will be an ongoing effort.

  15. Boron neutron capture therapy (BNCT): A radiation oncology perspective

    SciTech Connect

    Dorn, R.V. III (Mountain States Tumor Institute, Boise, ID (United States) Idaho National Engineering Lab., Idaho Falls, ID (United States))

    1994-03-30

    Boron neutron capture therapy (BNCT) offers considerable promise in the search for the ideal cancer therapy, a therapy which selectively and maximally damages malignant cells while sparing normal tissue. This bimodal treatment modality selectivity concentrates a boron compound in malignant cells, and then [open quotes]activates[close quotes] this compound with slow neutrons resulting in a highly lethal event within the cancer cell. This article reviews this treatment modality from a radiation oncology, biology, and physics perspective. The remainder of the articles in this special issue provide a survey of the current [open quotes]state-of-the-art[close quotes] in this rapidly expanding field, including information with regard to boron compounds and their localization. 118 refs., 3 figs.

  16. Thermal Neutron Capture y's (CapGam)

    DOE Data Explorer

    The National Nuclear Data Center (NNDC) presents two tables showing energy and photon intensity with uncertainties of gamma rays as seen in thermal-neutron capture.  One table is organized in ascending order of gamma energy, and the second is organized by Z, A of the target. In the energy-ordered table the three strongest transitions are indicated in each case. The nuclide given is the target nucleus in the capture reaction. The gamma energies given are in keV. The gamma intensities given are relative to 100 for the strongest transition. %I? (per 100 n-captures) for the strongest transition is given, where known. All data are taken from the Evaluated Nuclear Structure Data File (ENSDF), a computer file of evaluated nuclear structure data and from the eXperimental Unevaluated Nuclear Data List (XUNDL). (Specialized Interface)

  17. Accelerator-driven boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Edgecock, Rob

    2014-05-01

    Boron Neutron Capture Therapy is a binary treatment for certain types of cancer. It works by loading the cancerous cells with a boron-10 carrying compound. This isotope has a large cross-section for thermal neutrons, the reaction producing a lithium nucleus and alpha particle that kill the cell in which they are produced. Recent studies of the boron carrier compound indicate that the uptake process works best in particularly aggressive cancers. Most studied is glioblastoma multiforme and a trial using a combination of BNCT and X-ray radiotherapy has shown an increase of nearly a factor of two in mean survival over the state of the art. However, the main technical problem with BNCT remains producing a sufficient flux of neutrons for a reasonable treatment duration in a hospital environment. This paper discusses this issue.

  18. Neutron Capture Experiments on Unstable Nuclei

    SciTech Connect

    Schwantes, Jon M.; Sudowe, Ralf; Folden, Charles M., III; Nitsche, Heino; Hoffman, Darleane C.

    2005-01-15

    The overall objective of this project is the measurement of neutron capture cross sections of importance to stewardship science and astrophysical modeling of nucleosynthesis, while at the same time helping to train the next generation of scientists with expertise relevant to U.S. national nuclear security missions and to stewardship science. A primary objective of this project is to study neutron capture cross sections for various stable and unstable isotopes that will contribute to the Science Based Stockpile Stewardship (SBSS) program by providing improved data for modeling and interpretation of nuclear device performance. Much of the information obtained will also be important in astrophysical modeling of nucleosynthesis. Measurements of these neutron capture cross sections are being conducted in collaboration with researchers at the Los Alamos Neutron Science Center (LANSCE) facility using the unique Detector for Advanced Neutron Capture Experiments (DANCE). In our early discussions with the DANCE group, decisions were made on the first cross sections to be measured and how our expertise in target preparation, radiochemical separations chemistry, and data analysis could best be applied. The initial emphasis of the project was on preparing suitable targets of both natural and separated stable europium isotopes in preparation for the ultimate goal of preparing a sufficiently large target of radioactive 155Eu (t1/2 = 4.7 years) and other radioactive and stable species for neutron cross-section measurements at DANCE. Our Annual Report, ''Neutron Capture Experiments on Unstable Nuclei'' by J. M. Schwantes, R. Sudowe, C. M. Folden III, H. Nitsche, and D. C. Hoffman, submitted to NNSA in December 2003, gives details about the initial considerations and scope of the project. During the current reporting period, electroplated targets of natural Eu together with valuable, stable, and isotopically pure 151Eu and 153Eu, and isotopically separated 154Sm were measured for the first time at the DANCE facility in early 2004. The Eu targets, suitable blanks, Be backing foils, and standards had been sent to the DANCE group in early fall 2003. Some preliminary data analysis was performed and more sophisticated analysis has begun. We developed plans for a suitable computer system for data analysis within our group at Berkeley and had meetings with counterparts at Lawrence Livermore National Laboratory (LLNL) and LANL concerning analysis of these data. Our major emphasis in 2004 has been to develop the separations and processes ultimately required to prepare radioactive targets of 4.7-year 155Eu. Efforts continued to devise an optimum multiprocess procedure suitable for use in separating radioactive 155Eu already produced by irradiation of stable 154Sm in a high neutron flux reactor at the Institut Laue-Langevin in France and shipped to LANL (the 22-min 155Sm neutron-capture product decays to 155Eu). This separation is extremely demanding because the highly radioactive 155Eu must be isolated from about 20 times as much mass of samarium before a target can be prepared for DANCE measurements. After all the procedures have been fully tested the radioactive 155Eu will be separated. The same electroplating methods already used successfully to prepare stable Eu isotope targets will be used to prepare the 155Eu target for DANCE. Discussions were held with LANL radiochemists in the Chemistry (C) Division about appropriate facilities at LANL for conducting the full-scale separation and purification of the radioactive targets. Three more multiprocess separations were developed that generated less chemical and radioactive waste, but they must still be adapted for processing hundred-milligram quantities. Until these separations can be successfully implemented at this scale, standard HPLC procedures will be used for separating and preparing radioactive 155Eu, 2.6-year 147Pm, and 1.9-year 171Tm target materials. Future directions beyond the preparation of radioactive lanthanide targets include closer collaboration with both LLNL and LANL to prepare ac

  19. Action of Slow Neutrons on Rare Earth Elements

    Microsoft Academic Search

    G. Hevesy; Hilde Levi

    1936-01-01

    IN view of the discrepancy between the values obtained by different workers for the periods and the intensity of radiation emitted by the radio rare earth elements1-5 after neutron bombardment, we carried out a detailed investigation on this subject and also on the absorption of slow neutrons in rare earth elements. The latter measurements were carried out chiefly to ascertain

  20. A slow neutron polarimeter for the measurement of parity-odd neutron rotary power.

    PubMed

    Snow, W M; Anderson, E; Barrón-Palos, L; Bass, C D; Bass, T D; Crawford, B E; Crawford, C; Dawkins, J M; Esposito, D; Fry, J; Gardiner, H; Gan, K; Haddock, C; Heckel, B R; Holley, A T; Horton, J C; Huffer, C; Lieffers, J; Luo, D; Maldonado-Velázquez, M; Markoff, D M; Micherdzinska, A M; Mumm, H P; Nico, J S; Sarsour, M; Santra, S; Sharapov, E I; Swanson, H E; Walbridge, S B; Zhumabekova, V

    2015-05-01

    We present the design, description, calibration procedure, and an analysis of systematic effects for an apparatus designed to measure the rotation of the plane of polarization of a transversely polarized slow neutron beam as it passes through unpolarized matter. This device is the neutron optical equivalent of a crossed polarizer/analyzer pair familiar from light optics. This apparatus has been used to search for parity violation in the interaction of polarized slow neutrons in matter. Given the brightness of existing slow neutron sources, this apparatus is capable of measuring a neutron rotary power of d?/dz = 1 × 10(-7) rad/m. PMID:26026552

  1. Neutron tube design study for boron neutron capture therapy application

    SciTech Connect

    Verbeke, J.M.; Lee, Y.; Leung, K.N.; Vujic, J.; Williams, M.D.; Wu, L.K.; Zahir, N.

    1999-05-06

    Radio-frequency (RF) driven ion sources are being developed in Lawrence Berkeley National Laboratory (LBNL) for sealed-accelerator-tube neutron generator application. By using a 5-cm-diameter RF-driven multicusp source H{sup +} yields over 95% have been achieved. These experimental findings will enable one to develop compact neutron generators based on the D-D or D-T fusion reactions. In this new neutron generator, the ion source, the accelerator and the target are all housed in a sealed metal container without external pumping. Recent moderator design simulation studies have shown that 14 MeV neutrons could be moderated to therapeutically useful energy ranges for boron neutron capture therapy (BNCT). The dose near the center of the brain with optimized moderators is about 65% higher than the dose obtained from a typical neutron spectrum produced by the Brookhaven Medical Research Reactor (BMRR), and is comparable to the dose obtained by other accelerator-based neutron sources. With a 120 keV and 1 A deuteron beam, a treatment time of {approx}35 minutes is estimated for BNCT.

  2. The Detector for Advanced Neutron Capture Experiments at LANSCE

    Microsoft Academic Search

    J. L. Ullmann; R. C. Haight; L. Hunt; E. Seabury; R. S. Rundberg; J. B. Wilhelmy; M. M. Fowler; D. D. Strottman; F. Kaeppeler; R. Reifarth; M. Heil; E. P. Chamberlin

    2002-01-01

    The Detector for Advanced Neutron Capture Experiments (DANCE) is a 159-element 4pi barium fluoride array designed to study neutron capture on small quantities of radioactive material. It is being built on a 20m neutron flight path which views the \\

  3. Neutron degeneracy and plasma physics effects on radiative neutron captures in neutron star crust

    E-print Network

    P. S. Shternin; M. Beard; M. Wiescher; D. G. Yakovlev

    2012-07-25

    We consider the astrophysical reaction rates for radiative neutron capture reactions ($n,\\gamma$) in the crust of a neutron star. The presence of degenerate neutrons at high densities (mainly in the inner crust) can drastically affect the reaction rates. Standard rates assuming a Maxwell-Boltzmann distribution for neutrons can underestimate the rates by several orders of magnitude. We derive simple analytical expressions for reaction rates at a variety of conditions with account for neutron degeneracy. We also discuss the plasma effects on the outgoing radiative transition channel in neutron radiative capture reactions and show that these effects can also increase the reaction rates by a few orders of magnitude. In addition, using detailed balance, we analyze the effects of neutron degeneracy and plasma physics on reverse ($\\gamma,n$) photodisintegration. We discuss the dependence of the reaction rates on temperature and neutron chemical potential and outline the efficiency of these reactions in the neutron star crust.

  4. Thermal neutron capture gamma-rays

    SciTech Connect

    Tuli, J.K.

    1983-01-01

    The energy and intensity of gamma rays as seen in thermal neutron capture are presented. Only those (n,..cap alpha..), E = thermal, reactions for which the residual nucleus mass number is greater than or equal to 45 are included. These correspond to evaluations published in Nuclear Data Sheets. The publication source data are contained in the Evaluated Nuclear Structure Data File (ENSDF). The data presented here do not involve any additional evaluation. Appendix I lists all the residual nuclides for which the data are included here. Appendix II gives a cumulated index to A-chain evaluations including the year of publication. The capture gamma ray data are given in two tables - the Table 1 is the list of all gamma rays seen in (n,..gamma..) reaction given in the order of increasing energy; the Table II lists the gamma rays according to the nuclide.

  5. Slow neutron distribution in a temperature gradient

    SciTech Connect

    Molinari, V.G.; Pollachini, L.

    1985-12-01

    A set of equations that describes the diffusion of thermal neutrons is obtained from the energy-dependent Boltzmann equation. These equations are analogous to the phenomenological laws of the thermodynamic theory of irreversible processes and show, for instance, that as a temperatur gradient produces a neutron current (Soret effect), a density gradient yields an energy flow (Dufour effect). The method is applied to the ''two-temperature problem'' in order to gain better insight into the thermal diffusion phenomenon. The thermal diffusion of neutrons is shown to strongly depend on the scattering law of the two media where neutrons diffuse, and it is determined that some of the conclusions previously obtained are valid only for the case of a heavy gas moderator with the scat tering cross section independent of the energy.

  6. SCATTERING OF SLOW NEUTRONS BY A LIQUID

    Microsoft Academic Search

    George Vineyard

    1958-01-01

    The differential cross section for coherent scattering of thermal ; neutrons by a liquid is given in general by the Fourier transform of a time-; displaced radial density function. It is suggested that, to an adequate degree ; of approximation, this time-displaced function can be expressed as a convolution ; of the ordinary radial density function with a self-diffusion function

  7. Research needs for neutron capture therapy

    SciTech Connect

    NONE

    1995-12-01

    Key issues and questions addressed by the workshop related to optimization of Boron Neutron Capture Therapy (BNCT), in general, and to the possibility of success of the present BNCT trials at Brookhaven National Laboratory (BNL) and Massachusetts Institute of Technology (MIT), in particular. Both trials use nuclear fission reactors as neutron sources for BNCT of glioblastoma multiforme (BNL) and of deep seated melanoma (MIT). Presentations and discussions focussed on optimal boron-labeled compounds, mainly for brain tumors such as glioblastoma multiforme, and the best mode of compound delivery to the tumor. Also, optimizing neutron irradiation with dose delivery to the tumor cells and the issues of dosimetry of BNCT especially in the brain were discussed. Planning of treatment and of follow-up of patients, coordination of BNCT at various treatment sites, and the potential of delivering BNCT to various types of cancer with an appropriately tailored protocol were additional issues. The need for multicentric interdisciplinary cooperation among the different medical specialties was highlighted.

  8. The Detector for Advanced Neutron Capture Experiments at LANSCE

    NASA Astrophysics Data System (ADS)

    Ullmann, J. L.; Haight, R. C.; Hunt, L.; Seabury, E.; Rundberg, R. S.; Wilhelmy, J. B.; Fowler, M. M.; Strottman, D. D.; Kaeppeler, F.; Reifarth, R.; Heil, M.; Chamberlin, E. P.

    2002-12-01

    The Detector for Advanced Neutron Capture Experiments (DANCE) is a 159-element 4? barium fluoride array designed to study neutron capture on small quantities of radioactive material. It is being built on a 20m neutron flight path which views the "upper tier" water moderator at the Manuel J. Lujan Jr. Neutron Scattering Center at the Los Alamos Neutron Science Center. Monte Carlo calculations have suggested ways to minimize backgrounds due to neutron scattering events. Preliminary data on an 8 mg sample of 234U and a 0.5 mg sample of 151Sm have been taken using C6D6 detectors.

  9. Progress in neutron capture therapy for cancer

    SciTech Connect

    Allen, B.J.; Harrington, B.V. (eds.) (Australian Nuclear Science and Technology Organisation, Menai (Australia)); Moore, D.E. (ed.) (Sydney Univ. (Australia))

    1992-01-01

    Prognosis for some cancers is good, but for others, few patients will survive 12 months. This latter group of cancers is characterised by a proclivity to disseminate malignant cells in the host organ. In some cases systemic metastases occur, but in other cases, failure to achieve local control results in death. First among these cancers are the high grade brain tumours, astrocytoma 3,4 and glioblastoma multiforme. Local control of these tumors should lead to cure. Other cancers melanoma metastatic to the brain, for which a useful palliative therapy is not yet available, and pancreatic cancer for which localised control at an early stage could bring about improved prognosis. Patients with these cancers have little grounds for hope. Our primary objective is to reverse this situation with Neutron Capture Therapy (NCT). The purpose of this fourth symposium is to hasten the day whereby patients with these cancers can reasonably hope for substantial remissions.

  10. Progress in neutron capture therapy for cancer

    SciTech Connect

    Allen, B.J.; Harrington, B.V. [eds.] [Australian Nuclear Science and Technology Organisation, Menai (Australia); Moore, D.E. [ed.] [Sydney Univ. (Australia)

    1992-09-01

    Prognosis for some cancers is good, but for others, few patients will survive 12 months. This latter group of cancers is characterised by a proclivity to disseminate malignant cells in the host organ. In some cases systemic metastases occur, but in other cases, failure to achieve local control results in death. First among these cancers are the high grade brain tumours, astrocytoma 3,4 and glioblastoma multiforme. Local control of these tumors should lead to cure. Other cancers melanoma metastatic to the brain, for which a useful palliative therapy is not yet available, and pancreatic cancer for which localised control at an early stage could bring about improved prognosis. Patients with these cancers have little grounds for hope. Our primary objective is to reverse this situation with Neutron Capture Therapy (NCT). The purpose of this fourth symposium is to hasten the day whereby patients with these cancers can reasonably hope for substantial remissions.

  11. Preparation of radioactive rare earth targets for neutron capture study

    Microsoft Academic Search

    G. G. Miller; P. Z. Rogers; P. Palmer; D. Dry; R. Rundberg; M. Fowler; J. Wilhelmy

    2005-01-01

    Summary  The neutron capture behavior of certain radioactive rare earth nuclides, among them 171Tm and 151Sm, is of interest for astrophysical reasons and for the interpretation of radiochemical data from underground nuclear tests. In order to measure neutron capture excitation functions for these radionuclides, targets were produced that met stringent requirements. This paper describes the purification chemistry and target preparation methods

  12. Neutron capture therapy: Years of experimentation---Years of reflection

    SciTech Connect

    Farr, L.E.

    1991-12-16

    This report describes early research on neutron capture therapy over a number of years, beginning in 1950, speaking briefly of patient treatments but dwelling mostly on interpretations of our animal experiments. This work carried out over eighteen years, beginning over forty years ago. Yet, it is only fitting to start by relating how neutron capture therapy became part of Brookhaven's Medical Research Center program.

  13. Boron thermal/epithermal neutron capture therapy

    SciTech Connect

    Fairchild, R.G.

    1982-01-01

    The development of various particle beams for radiotherapy represents an attempt to improve dose distribution, and to provide high LET radiations which are less sensitive to ambient physical and radiobiological factors such as oxygen tension, cell cycle, and dose rate. In general, a compromise is necessary as effective RBE is reduced in order to spread the dose distribution over the anticipated tumor volume. The approach of delivering stable non-toxic isotopes to tumor, and then activating these atoms subsequently via an external radiation beam has mator advantages; problems associated with high uptake of these isotopes in competing cell pools are obviated, and the general tumor volume can be included in the treatment field of the activating beam. As long as the normal tissues supporting tumor show a low uptake of the isotope to be activated, and as long as the range of the reaction products is short, dose will be restricted to tumor, with a consequent high therapeutic ratio. Neutron Capture Therapy (NCT) is generally carried out by activating boron-10 with low energy neutrons. The range of the high LET, low OER particles from the /sup 10/B(n, ..cap alpha..)/sup 7/Li reaction is approx. 10..mu.., or one cell diameter, a situation that is optimal for cell killing. Significant advantages may be gained by using the NCT procedure in conjunction with improved tissue penetration provided with epithermal or filtered beams, and new compounds showing physiological binding to tumor.

  14. Infrared Observations of Neutron-Capture Elements in Planetary Nebulae

    E-print Network

    N. C. Sterling; H. L. Dinerstein

    2005-06-10

    We present results from an ongoing survey of the infrared emission lines [Kr III] 2.199 and [Se IV] 2.287 micron in Galactic planetary nebulae (PNe). Krypton and selenium may be produced by slow neutron-capture nucleosynthesis (the ``s-process'') during the asymptotic giant branch (AGB) phase of PN progenitor stars, and brought to the surface by convective dredge-up before PN ejection. We detect emission from Se and Kr in 65 of 114 Galactic PNe, and use the line fluxes to derive ionic abundances. We employ ionization correction factors based on coincidences of ionization potentials to calculate total elemental abundances, and discuss photoionization models designed to test the veracity of these corrections. The derived Se and Kr abundances of our targets range from approximately solar to enriched by a factor of 5, which indicates varying degrees of dredge-up and s-process efficiencies in the progenitor stars. In PNe exhibiting emission from both Se and Kr, we find that the relative abundances of these elements are generally in agreement with predictions from theoretical models of s-process nucleosynthesis. We examine our results for correlations between s-process enrichments and other nebular properties, such as CNO abundances, morphology, and characteristics of the central stars. PNe with Wolf-Rayet central stars tend to exhibit more elevated Se and Kr abundances than other nebulae. Bipolar nebulae, believed to arise from the most massive of PN progenitors, may have lower n-capture abundances than elliptical PNe.

  15. Neutron Slowing Down in a Detector with Absorption Sara A. Pozzi*

    E-print Network

    Pázsit, Imre

    Neutron Slowing Down in a Detector with Absorption Sara A. Pozzi* Oak Ridge National Laboratory, P of scattering collisions undergone by fast neutrons as they slow down until they are absorbed was presented realistic case of neutron slowing down in a homogeneous mixture. The formulas are derived and evaluated

  16. Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy

    DOEpatents

    Miura, M.; Slatkin, D.N.

    1997-03-18

    A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na{sub 4}B{sub 12}I{sub 11}SSB{sub 12}I{sub 11}, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy. 1 fig.

  17. Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy

    DOEpatents

    Miura, M.; Slatkin, D.N.

    1995-10-03

    A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na{sub 4}B{sub 12}I{sub 11}SSB{sub 12}I{sub 11}, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy. 1 fig.

  18. Neutron Capture Gamma-Ray Libraries for Nuclear Applications

    SciTech Connect

    Sleaford, B W; Firestone, R B; Summers, N; Escher, J; Hurst, A; Krticka, M; Basunia, S; Molnar, G; Belgya, T; Revay, Z; Choi, H D

    2010-11-04

    The neutron capture reaction is useful in identifying and analyzing the gamma-ray spectrum from an unknown assembly as it gives unambiguous information on its composition. this can be done passively or actively where an external neutron source is used to probe an unknown assembly. There are known capture gamma-ray data gaps in the ENDF libraries used by transport codes for various nuclear applications. The Evaluated Gamma-ray Activation file (EGAF) is a new thermal neutron capture database of discrete line spectra and cross sections for over 260 isotopes that was developed as part of an IAEA Coordinated Research project. EGAF is being used to improve the capture gamma production in ENDF libraries. For medium to heavy nuclei the quasi continuum contribution to the gamma cascades is not experimentally resolved. The continuum contains up to 90% of all the decay energy and is modeled here with the statistical nuclear structure code DICEBOX. This code also provides a consistency check of the level scheme nuclear structure evaluation. The calculated continuum is of sufficient accuracy to include in the ENDF libraries. This analysis also determines new total thermal capture cross sections and provides an improved RIPL database. For higher energy neutron capture there is less experimental data available making benchmarking of the modeling codes more difficult. They are investigating the capture spectra from higher energy neutrons experimentally using surrogate reactions and modeling this with Hauser-Feshbach codes. This can then be used to benchmark CASINO, a version of DICEBOX modified for neutron capture at higher energy. This can be used to simulate spectra from neutron capture at incident neutron energies up to 20 MeV to improve the gamma-ray spectrum in neutron data libraries used for transport modeling of unknown assemblies.

  19. Measurement of longitudinal asymmetry in neutron radiative capture reactions

    Microsoft Academic Search

    Y. Masuda; T. Adachi; S. Ishimoto; E. Kikutani; M. Kohgi; H. Koiso; A. Masaike; K. Morimoto

    1988-01-01

    The helicity dependence was measured in neutron radiative capture reactions for various nuclei using a polarized low-energy neutron beam. The neutron spin was polarized upon passing through a dynamically polarized proton filter. The neutron polarization was around 72%. The value of the asymmetry AL in the p-wave resonance of 139La at 0.734 eV was (9.4 +\\/- 0.4)%. Measurements were also

  20. Enhancing the Detector for Advanced Neutron Capture Experiments

    NASA Astrophysics Data System (ADS)

    Couture, A.; Mosby, S.; Baramsai, B.; Bredeweg, T. A.; Jandel, M.; Macon, K.; O'Donnell, J. M.; Rusev, G.; Taddeucci, T. N.; Ullmann, J. L.; Walker, C. L.

    2015-05-01

    The Detector for Advanced Neutron Capture Experiments (DANCE) has been used for extensive studies of neutron capture, gamma decay, photon strength functions, and prompt and delayed fission-gamma emission. Despite these successes, the potential measurements have been limited by the data acquisition hardware. We report on a major upgrade of the DANCE data acquisition that simultaneously enables strait-forward coupling to auxiliary detectors, including high-resolution high-purity germanium detectors and neutron tagging array. The upgrade will enhance the time domain accessible for time-of-flight neutron measurements as well as improve the resolution in the DANCE barium fluoride crystals for photons.

  1. General Electric PETtrace cyclotron as a neutron source for boron neutron capture therapy 

    E-print Network

    Bosko, Andrey

    2005-11-01

    This research investigates the use of a PETtrace cyclotron produced by General Electric (GE) as a neutron source for boron neutron capture therapy (BNCT). The GE PETtrace was chosen for this investigation because this type of cyclotron is popular...

  2. General Electric PETtrace cyclotron as a neutron source for boron neutron capture therapy

    E-print Network

    Bosko, Andrey

    2005-11-01

    This research investigates the use of a PETtrace cyclotron produced by General Electric (GE) as a neutron source for boron neutron capture therapy (BNCT). The GE PETtrace was chosen for this investigation because this type of cyclotron is popular...

  3. Radiobiology of normal rat lung in Boron Neutron Capture Therapy

    E-print Network

    Kiger, Jingli Liu

    2006-01-01

    Boron Neutron Capture Therapy (BNCT) is a binary cancer radiation therapy that utilizes biochemical tumor cell targeting and provides a mixed field of high and low Linear Energy Transfer (LET) radiation with differing ...

  4. Prompt gamma rays from thermal-neutron capture

    Microsoft Academic Search

    M. A. Lone; R. A. Leavitt; D. A. Harrison

    1981-01-01

    A catalog of ..gamma..-rays emitted following thermal-neutron capture in natural elements is presented. In Table I, ..gamma..-rays are arranged in order of increasing energy. Each line contains the ..gamma..-ray energy, intensity, element identification, thermal-neutron radiative-capture cross section, and the energies and intensities of two of the more abundant ..gamma..-rays associated with that element. In Table II, ..gamma..-rays are arranged by

  5. Stellar neutron capture cross sections of the Gd isotopes

    Microsoft Academic Search

    K. Wisshak; F. Voss; F. Käppeler; L. Kazakov; N. Kornilov; G. Reffo

    1995-01-01

    The neutron capture cross sections of 152Gd, 154Gd, 155Gd, 156Gd, 157Gd, and 158Gd were measured in the energy range from 3 to 225 keV at the Karlsruhe 3.75 MV Van de Graaff accelerator. Neutrons were produced via the 7Li(p,n)7Be reaction by bombarding metallic Li targets with a pulsed proton beam. Capture events were registered with the Karlsruhe 4pi Barium Fluoride

  6. Neutron capture therapy: Years of experimentation---Years of reflection

    SciTech Connect

    Farr, L.E.

    1991-12-16

    This report describes early research on neutron capture therapy over a number of years, beginning in 1950, speaking briefly of patient treatments but dwelling mostly on interpretations of our animal experiments. This work carried out over eighteen years, beginning over forty years ago. Yet, it is only fitting to start by relating how neutron capture therapy became part of Brookhaven`s Medical Research Center program.

  7. Stellar neutron capture cross sections of the Lu isotopes

    Microsoft Academic Search

    K. Wisshak; F. Voss; F. Kaeppeler; L. Kazakov

    2006-01-01

    The neutron capture cross sections of 175Lu and 176Lu have been measured in the energy range 3 225 keV at the Karlsruhe 3.7 MV Van de Graaff accelerator. Neutrons were produced via the 7Li(p,n)7Be reaction by bombarding metallic Li targets with a pulsed proton beam, and capture events were registered with the Karlsruhe 4pi barium fluoride detector. The cross sections

  8. Cosmogenic neutron-capture-produced nuclides in stony meteorites

    SciTech Connect

    Spergel, M.S.; Reedy, R.C.; Lazareth, O.W.; Levy, P.W.

    1985-01-01

    The distribution of neutrons with energies below 15 MeV in spherical stony meteoroids is calculated using the ANISN neutron-transport code. The source distributions and intensities of neutrons are calculated using cross sections for the production of tritium. The meteoroid's radius and chemical composition strongly influence the total neutron flux and the neutron energy spectrum, while the location within a meteoroid only affects the relative neutron intensities. Meteoroids need to have radii of more than 50 g/cm/sup 2/ before they have appreciable fluxes of neutrons near thermal energies. Meteoroids with high hydrogen or low iron contents can thermalize neutrons better than chondrites. Rates for the production of /sup 60/Co, /sup 59/Ni, and /sup 36/Cl are calculated with evaluated neutron-capture cross sections and neutron fluxes determined for carbonaceous chondrites with high hydrogen contents, L-chondrites, and aubrites. For most meteoroids with radii < 300 g/cm/sup 2/, the production rates of these neutron-capture nuclides increase monotonically with depth. The highest calculated /sup 60/Co production rate in an ordinary chondrite is 375 atoms/(min g-Co) at the center of a meteoroid with a 250 g/cm/sup 2/ radius. The production rates calculated for spallogenic /sup 60/Co and /sup 59/Ni are greater than the neutron-capture rates for radii less than approx.50-75 g/cm/sup 2/. Only for very large meteoroids and chlorine-rich samples is the neutron-capture production of /sup 36/Cl important. The results of these calculations are compared with those of previous calculations and with measured activities in many meteorites. 44 refs., 15 figs., 1 tab.

  9. Neutron Capture Cross Sections: From Theory to Experiments and Back

    SciTech Connect

    Mengoni, A. [CERN, CH-1211 Geneva 23 (Switzerland); ENEA, Via Don Fiammelli, 2 - 40129 Bologna (Italy)

    2005-05-24

    The method for an experimental determination of the stellar enhancement factor for the cross section of the 151Sm(n,{gamma}) reaction process is proposed. This study offered the pretext for an excursus on the interconnections between capture and dissociation reactions and the interplay between theory and experiments in the determination of neutron capture cross sections.

  10. Neutron Capture Cross Sections: From Theory to Experiments and Back

    Microsoft Academic Search

    Alberto Mengoni

    2005-01-01

    The method for an experimental determination of the stellar enhancement factor for the cross section of the 151Sm(n,gamma) reaction process is proposed. This study offered the pretext for an excursus on the interconnections between capture and dissociation reactions and the interplay between theory and experiments in the determination of neutron capture cross sections.

  11. Neutron capture studies of 206Pb at a cold neutron beam

    NASA Astrophysics Data System (ADS)

    Schillebeeckx, P.; Belgya, T.; Borella, A.; Kopecky, S.; Mengoni, A.; Quétel, C. R.; Szentmiklósi, L.; Trešl, I.; Wynants, R.

    2013-11-01

    Gamma-ray transitions following neutron capture in 206Pb have been studied at the cold neutron beam facility of the Budapest Neutron Centre using a metallic sample enriched in 206Pb and a natural lead nitrate powder pellet. The measurements were performed using a coaxial HPGe detector with Compton suppression. The observed -rays have been incorporated into a decay scheme for neutron capture in 206Pb . Partial capture cross sections for 206Pb(n,) at thermal energy have been derived relative to the cross section for the 1884keV transition after neutron capture in 14N . From the average crossing sum a total thermal neutron capture cross section of mb was derived for the 206Pb(n,) reaction. The thermal neutron capture cross section for 206Pb has been compared with contributions due to both direct capture and distant unbound s-wave resonances. From the same measurements a thermal neutron-induced capture cross section of mb was determined for the 207Pb(n,) reaction.

  12. Neutron capture and fission in /sup 254g/ Es

    SciTech Connect

    Halperin, J.; Bigelow, J.E.; O'Kelley, G.D.; Oliver, J.H.; Wiggins, J.T.

    1985-07-01

    Integral neutron capture and neutron fission cross sections have been measured for the 276-day /sup 254g/ Es. Thermal cross sections and resonance integrals were evaluated using a cadmium filter technique. Capture cross sections were determined from alpha-particle spectrum measurements following neutron irradiations with cobalt flux monitors. Fission cross sections were measured using fission track detection techniques with STTU monitors. The fission cross-section values compared favorably with an absorption cross-section determination from a burnout experiment of SVTEs-SVUEs. The integral neutron capture and fission cross sections determined for /sup 254g/ Es are: sigma /sub c/ /sup th/ = 28.3 + or - 2.5 and I /sub c/ = 18.2 + or - 1.5 b, and sigma /sub F/ /sup th/ = 1970 + or - 200 and I /sub F/ = 1200 + or - 250 b.

  13. Neutron capture rates on radioactive nuclides – DANCE

    Microsoft Academic Search

    R. Reifarth; U. Agvaanluvsan; A. Alpizar-Vicente; T. A. Bredeweg; E.-I. Esch; U. Greife; R. C. Haight; R. Hatarik; F. Herwig; J. M. O’Donnell; R. S. Rundberg; J. M. Schwantes; J. L. Ullmann; D. J. Vieira; J. M. Wouters

    2006-01-01

    The nucleosynthesis of the elements including their stellar sites is one of the most interesting nuclear physics challenges. Information on reaction rates for neutron induced reactions have a direct impact on existing stellar models. Except for the stable isotopes, very few neutron-induced reactions in the energy range of interest have been measured to date. DANCE measurements on stable and unstable

  14. SPIN-DEPENDENT SCATTERING LENGTHS OF SLOW NEUTRONS WITH NUCLEI BY PSEUDOMAGNETIC MEASUREMENTS

    E-print Network

    Boyer, Edmond

    L-263 SPIN-DEPENDENT SCATTERING LENGTHS OF SLOW NEUTRONS WITH NUCLEI BY PSEUDOMAGNETIC MEASUREMENTS-sur-Yvette, France Résumé. 2014 En mesurant la précession de spin de neutrons en fonction de la polarisation vu par les noyaux. Abstract. - The spin-dependent scattering length of slow neutrons by the nuclei 23

  15. Interplay of direct and compound-nucleus mechanisms in neutron capture by light nuclides

    SciTech Connect

    Raman, S.; Kahane, S.; Lynn, J.E.

    1988-01-01

    The authors discuss the direct-capture theory pertaining to primary electric-dipole (E1) transitions following slow-neutron capture. For approximately 20 light nuclides that we have studied, estimates of direct-capture cross sections using optical-model potentials with physically realistic parameters are in reasonable agreement with the data. Minor disagreements that exist are consistent with extrapolations to light nuclides of generally accepted formulations of compound-nucleus capture. In dealing with nuclei soft to vibrations, we have considered the possible effects of coupling of the collective motion with the optical potential in the framework of R-matrix theory. In such cases, we find that the inclusion of inelastic channels results in systematic changes in the calculated cross sections.

  16. Cosmogenic neutron-capture-produced nuclides in stony meteorites

    NASA Technical Reports Server (NTRS)

    Spergel, M. S.; Reedy, R. C.; Lazareth, O. W.; Levy, P. W.; Slatest, L. A.

    1986-01-01

    The complete neutron-flux results and production rates for Cl-36, Ni-59, and Co-60 in stony meteorites of various radii and composition are presented. The relative neutron source strengths and neutron production-versus-depth profiles were determined by using calculated H-3 production rates. The absolute source strengths were normalized to that determined for the moon by Woolum et al. (1975). The energy spectrum of the source neutrons and the neutron transport calculations, which employed the ANISN computer code, were similar to those used for the moon by Lingenfelter et al. (1972). The production rates of the three radionuclides were determined as a function of depth in various spherical meteoroids from the calculated equilibrium neutron-flux distributions and from energy-dependent neutron-capture cross sections. Rates for producing these radionuclides by spallation reactions were also calculated.

  17. Neutron capture strategy and technique developments for GNEP

    SciTech Connect

    Couture, Aaron Joseph [Los Alamos National Laboratory

    2008-01-01

    The initial three years of neutron capture measurements have been very successful in providing data for the Advanced Fuel Cycle Initiative/Global Nuclear Energy Partnership (AFCI/GNEP) program. Now that the most straightforward measurements have been completed, additional technical challenges face future measurements. In particular, techniques are needed to perform measurements that exhibit at least one of three major problems -- large fission:capture ratios, large capture:capture ratios, and high intrinsic activity samples. This paper will set forward a plan for attacking these technical challenges and moving forward with future measurements.

  18. Neutron capture therapy beam design at Harwell.

    PubMed

    Constantine, G

    1990-01-01

    At Harwell, we have progressed from designing, building, and using small-diameter beams of epithermal neutrons for radiobiology studies to designing a radiotherapy facility for the 25-MW research reactor DIDO. The program is well into the survey phase, where the main emphasis is on tailoring the neutron spectrum. The incorporation of titanium and vanadium in an aluminium spectrum shaper in the D2O reflector has been shown to yield a significant reduction in the mean energy of neutrons incident on the patient by suppression of streaming through the cross-section window in aluminium at 25 keV. PMID:2176459

  19. Virtual Gamma Ray Radiation Sources through Neutron Radiative Capture

    SciTech Connect

    Scott Wilde, Raymond Keegan

    2008-07-01

    The countrate response of a gamma spectrometry system from a neutron radiation source behind a plane of moderating material doped with a nuclide of a large radiative neutron capture cross-section exhibits a countrate response analogous to a gamma radiation source at the same position from the detector. Using a planar, surface area of the neutron moderating material exposed to the neutron radiation produces a larger area under the prompt gamma ray peak in the detector than a smaller area of dimensions relative to the active volume of the gamma detection system.

  20. ALOHA with capture over slow and fast fading radio channels with coding and diversity

    Microsoft Academic Search

    I. M. I. Habbab; M. Kavehrad; C.-E. W. Sundberg

    1989-01-01

    The effects of capture on the average system throughput and delay performance of slotted ALOHA were analyzed for slow and fast Rayleigh fading radio channels. A short-range multipoint-to-base station packet radio network is considered. It is shown that larger capture effects and thus improved network performance can be achieved with proper choice of modulation. It is also shown that the

  1. Determination and production of an optimal neutron energy spectrum for boron neutron capture therapy

    Microsoft Academic Search

    Darren Leo Bleuel

    2003-01-01

    An accelerator-based neutron irradiation facility employing an electrostatic quadrupole (ESQ) accelerator for Boron Neutron Capture Therapy (BNCT) has been proposed at Lawrence Berkeley National Laboratory. In this dissertation, the properties of an ideal neutron beam for delivering a maximized dose to a glioblastoma multiforme tumor in a reasonable time while minimizing the dose to healthy tissue is examined. A variety

  2. New opportunities in neutron capture research using advanced pulsed neutron sources

    SciTech Connect

    Bowman, C.D.

    1987-08-01

    The extraordinary neutron intensities available from the new spallation pulsed neutron sources open up exciting opportunities for basic and applied research in neutron nuclear physics. Prospective experiments are reviewed with particular attention to those with a strong connection to capture gamma-ray spectroscopy.

  3. Thermal-neutron capture for A=26-35

    SciTech Connect

    Chunmei, Z.; Firestone, R.B.

    2001-06-01

    The prompt gamma-ray data of thermal- neutron captures fornuclear mass number A=26-35 had been evaluated and published in "ATOMICDATA AND NUCLEAR DATA TABLES, 26, 511 (1981)". Since that time themanyexperimental data of the thermal-neutron captures have been measuredand published. The update of the evaluated prompt gamma-ray data is verynecessary for use in PGAA of high-resolution analytical prompt gamma-rayspectroscopy. Besides, the evaluation is also very needed in theEvaluated Nuclear Structure Data File, ENSDF, because there are no promptgamma-ray data in ENSDF. The levels, prompt gamma-rays and decay schemesof thermal-neutron captures for nuclides (26Mg, 27Al, 28Si, 29Si, 30Si,31P, 32S, 33S, 34S, and 35Cl) with nuclear mass number A=26-35 have beenevaluated on the basis of all experimental data. The normalizationfactors, from which absolute prompt gamma-ray intensity can be obtained,and necessary comments are given in the text. The ENSDF format has beenadopted in this evaluation. The physical check (intensity balance andenergy balance) of evaluated thermal-neutron capture data has been done.The evaluated data have been put into Evaluated Nuclear Structure DataFile, ENSDF. This evaluation may be considered as an update of the promptgamma-ray from thermal-neutron capture data tables as published in"ATOMIC DATA AND NUCLEAR DATA TABLES, 26, 511 (1981)".

  4. Thermal-neutron capture for A=36-44

    SciTech Connect

    Chunmei, Z.; Firestone, R.B.

    2003-01-01

    The prompt gamma-ray data of thermal- neutron captures fornuclear mass number A=26-35 had been evaluated and published in "ATOMICDATA AND NUCLEAR DATA TABLES, 26, 511 (1981)". Since that time the manyexperimental data of the thermal-neutron captures have been measured andpublished. The update of the evaluated prompt gamma-ray data is verynecessary for use in PGAA of high-resolution analytical prompt gamma-rayspectroscopy. Besides, the evaluation is also very needed in theEvaluated Nuclear Structure Data File, ENSDF, because there are no promptgamma-ray data in ENSDF. The levels, prompt gamma-rays and decay schemesof thermal-neutron captures fornuclides (26Mg, 27Al, 28Si, 29Si, 30Si,31P, 32S, 33S, 34S, and 35Cl) with nuclear mass number A=26-35 have beenevaluated on the basis of all experimental data. The normalizationfactors, from which absolute prompt gamma-ray intensity can be obtained,and necessary comments are given in the text. The ENSDF format has beenadopted in this evaluation. The physical check (intensity balance andenergy balance) of evaluated thermal-neutron capture data has been done.The evaluated data have been put into Evaluated Nuclear Structure DataFile, ENSDF. This evaluation may be considered as an update of the promptgamma-ray from thermal-neutron capture data tables as published in"ATOMIC DATA AND NUCLEAR DATA TABLES, 26, 511 (1981)".

  5. Measurement of the scattering cross section of slow neutrons on liquid parahydrogen from neutron transmission

    NASA Astrophysics Data System (ADS)

    Grammer, K. B.; Alarcon, R.; Barrón-Palos, L.; Blyth, D.; Bowman, J. D.; Calarco, J.; Crawford, C.; Craycraft, K.; Evans, D.; Fomin, N.; Fry, J.; Gericke, M.; Gillis, R. C.; Greene, G. L.; Hamblen, J.; Hayes, C.; Kucuker, S.; Mahurin, R.; Maldonado-Velázquez, M.; Martin, E.; McCrea, M.; Mueller, P. E.; Musgrave, M.; Nann, H.; Penttilä, S. I.; Snow, W. M.; Tang, Z.; Wilburn, W. S.

    2015-05-01

    Liquid hydrogen is a dense Bose fluid whose equilibrium properties are both calculable from first principles using various theoretical approaches and of interest for the understanding of a wide range of questions in many-body physics. Unfortunately, the pair correlation function g (r ) inferred from neutron scattering measurements of the differential cross section d/? d ? from different measurements reported in the literature are inconsistent. We have measured the energy dependence of the total cross section and the scattering cross section for slow neutrons with energies between 0.43 and 16.1 meV on liquid hydrogen at 15.6 K (which is dominated by the parahydrogen component) using neutron transmission measurements on the hydrogen target of the NPDGamma collaboration at the Spallation Neutron Source at Oak Ridge National Laboratory. The relationship between the neutron transmission measurement we perform and the total cross section is unambiguous, and the energy range accesses length scales where the pair correlation function is rapidly varying. At 1 meV our measurement is a factor of 3 below the data from previous work. We present evidence that these previous measurements of the hydrogen cross section, which assumed that the equilibrium value for the ratio of orthohydrogen and parahydrogen has been reached in the target liquid, were in fact contaminated with an extra nonequilibrium component of orthohydrogen. Liquid parahydrogen is also a widely used neutron moderator medium, and an accurate knowledge of its slow neutron cross section is essential for the design and optimization of intense slow neutron sources. We describe our measurements and compare them with previous work.

  6. Sublethal and potentially lethal damage repair on thermal neutron capture therapy

    SciTech Connect

    Utsumi, H.; Ichihashi, M.; Kobayashi, T.; Elkind, M.M. (Kyoto Univ. (Japan))

    1989-07-01

    Tonicity shock or caffeine postirradiation treatment makes evident fast-type potentially lethal damage (PLD). Caffeine expresses fast-type PLD more efficiently than tonicity shock in X-irradiated B-16 mouse melanoma cells, compared with V79 Chinese hamster cells. The survival curves of thermal neutrons for either V79 or B-16 cells exhibit no shoulder. Neither V79 nor B-16 cells show the sublethal damage (SLD) repair of thermal neutrons. Caffeine-sensitive fast-type PLD repairs exist in X-irradiated B-16 cells, as well as V79 cells. The fast-type PLD repair of B-16 cells exposed to thermal neutrons alone is rather less than that of X-irradiated cells. Furthermore, an extremely low level of fast-type PLD repair of B-16 cells with 10B1-paraboronophenylalanine (BPA) preincubation (20 hours) followed by thermal neutron irradiation indicated that 10B(n,alpha)7Li reaction effectively eradicates actively growing melanoma cells. The plateau-phase B-16 cells are well able to repair the slow-type PLD of X-rays. However, cells can not repair the slow-type PLD induced by thermal neutron irradiation with or without 10B1-BPA preincubation. These results suggest that thermal neutron capture therapy can effectively kill radioresistant melanoma cells in both proliferating and quiescent phases.

  7. Neutron-capture therapy of brain tumours: neutron sources, neutron-capture drugs, biological tests and clinical perspectives in the Czech Republic.

    PubMed

    Burian, J; Marek, M; Mares, V; Drahota, Z

    1997-01-01

    The paper reviews neutron sources, chemical compounds and clinical perspectives of the boron neutron-capture therapy of brain tumours. Special attention is paid to the physical characteristics and biological effectiveness of the epithermal neutron beam constructed at the LVR-15 nuclear reactor at Rez near Prague. PMID:9727499

  8. Non-reactor neutron sources for BNCT (Boron Neutron Capture Therapy)

    Microsoft Academic Search

    T. J. Dolan; E. H. Ottewitte; E. E. Wills; W. A. Neuman; D. M. Woodall

    1989-01-01

    The focus of this study is the indentification of key feasibility issues for the use of non-reactor neutron sources for Boron Neutron Capture Therapy (BNCT). Of the non-reactor neutron sources surveyed, the ⁷Li(p,n) reaction appears to be the most favorable for producing epithermal neutrons for BNCT, and RFQ accelerators are best for producing the desired proton beam. At a proton

  9. Neutron capture rates on radioactive nuclides - DANCE

    NASA Astrophysics Data System (ADS)

    Reifarth, R.; Agvaanluvsan, U.; Alpizar-Vicente, A.; Bredeweg, T. A.; Esch, E.-I.; Greife, U.; Haight, R. C.; Hatarik, R.; Herwig, F.; O'Donnell, J. M.; Rundberg, R. S.; Schwantes, J. M.; Ullmann, J. L.; Vieira, D. J.; Wouters, J. M.

    2006-10-01

    The nucleosynthesis of the elements including their stellar sites is one of the most interesting nuclear physics challenges. Information on reaction rates for neutron induced reactions have a direct impact on existing stellar models. Except for the stable isotopes, very few neutron-induced reactions in the energy range of interest have been measured to date. DANCE measurements on stable and unstable isotopes can provide many of the missing key reactions that are needed to understand the nucleosynthesis of the heavy elements, which is illustrated at the example of the 151Sm(n,?) reaction.

  10. Neutron capture and neutron-induced fission experiments on americium isotopes with DANCE

    SciTech Connect

    Jandel, M.; Bredeweg, T. A.; Fowler, M. M.; Bond, E. M.; Couture, A.; Haight, R. C.; Keksis, A. L.; O'Donnell, J. M.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M. [Los Alamos National Laboratory, Los Alamos, NM, 87545 (United States); Stoyer, M. A.; Wu, C. Y.; Becker, J. A.; Haslett, R. J.; Henderson, R. A. [Lawrence Livermore National Laboratory, Livermore, CA, 94550 (United States)

    2009-01-28

    Neutron capture cross section data on Am isotopes were measured using the Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory. The neutron capture cross section was determined for {sup 241}Am for neutron energies between thermal and 320 keV. Preliminary results were also obtained for {sup 243}Am for neutron energies between 10 eV and 250 keV. The results on concurrent neutron-induced fission and neutron-capture measurements on {sup 242m}Am will be presented where the fission events were actively triggered during the experiments. In these experiments, a Parallel-Plate Avalanche Counter (PPAC) detector that surrounds the target located in the center of the DANCE array was used as a fission-tagging detector to separate (n,{gamma}) events from (n,f) events. The first direct observation of neutron capture on {sup 242m}Am in the resonance region in between 2 and 9 eV of the neutron energy was obtained.

  11. Neutron capture and neutron-induced fission experiments on americium isotopes with DANCE

    SciTech Connect

    Jandel, Marian [Los Alamos National Laboratory

    2008-01-01

    Neutron capture cross section data on Am isotopes were measured using the Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory. The neutron capture cross section was determined for {sup 241}Am for neutron energies between thermal and 320 keV. Preliminary results were also obtained for {sup 243}Am for neutron energies between 35 eV and 200 keV. The results on concurrent neutron-induced fission and neutron-capture measurements on {sup 242m}Am will be presented, where the fission events were actively triggered during the experiments. In these experiments, the Parallel-Plate Avalanche Counter (PPAC) detector that surrounds the target located in the center of the DANCE array was used as a fission-tagging detector to separate (n,{gamma}) from (n,f) events. The first evidence of neutron capture on {sup 242m}Am in the resonance region in between 2 and 9 eV of the neutron energy was obtained.

  12. Continuum quasiparticle random phase approximation for astrophysical direct neutron capture reaction of neutron-rich nuclei

    E-print Network

    Masayuki Matsuo

    2014-10-31

    We formulate a many-body theory to calculate the cross section of direct radiative neutron capture reaction by means of the Hartree-Fock-Bogoliubov mean-field model and the continuum quasiparticle random phase approximation (QRPA). A focus is put on very neutron-rich nuclei and low-energy neutron kinetic energy in the range of O(1 keV) - O(1 MeV), relevant for the rapid neutron-capture process of nucleosynthesis. We begin with the photo-absorption cross section and the E1 strength function, then, in order to apply the reciprocity theorem, we decompose the cross section into partial cross sections corresponding to different channels of one- and two-neutron emission decays of photo-excited states. Numerical example is shown for the photo-absorption of $^{142}$Sn and the neutron capture of $^{141}$Sn.

  13. Radiative Neutron Capture on Carbon-14 in Effective Field Theory

    E-print Network

    Gautam Rupak; Lakma Fernando; Akshay Vaghani

    2012-04-19

    The cross section for radiative capture of neutron on carbon-14 is calculated using the model-independent formalism of halo effective field theory. The dominant contribution from E1 transition is considered, and the cross section is expressed in terms of elastic scattering parameters of the effective range expansion. Contributions from both resonant and non-resonant interaction are calculated. Significant interference between these leads to a capture contribution that deviates from simple Breit-Wigner resonance form.

  14. Thermal neutron capture cross sections of the palladium isotopes

    Microsoft Academic Search

    M. Krticka; R. B. Firestone; D. P. McNabb; B. Sleaford; U. Agvaanluvsan; T. Belgya; Z. S. Revay

    2008-01-01

    Precise thermal neutron capture gamma-ray cross sections sigmagamma were measured for all elements with Z=1-83,90, and 92, except for He and Pm, at the Budapest Reactor. These data were evaluated with additional information from the literature to generate the Evaluated Gamma-ray Activation File (EGAF). Isotopic radiative neutron cross sections can be deduced from the total transition cross section feeding the

  15. Thermal neutron capture cross sections of the palladium isotopes

    Microsoft Academic Search

    M. Krticka; R. B. Firestone; D. P. McNabb; B. Sleaford; U. Agvaanluvsan; T. Belgya; Z. S. Revay

    2008-01-01

    Precise thermal neutron capture -ray cross sections {sub } were measured for all elements with Z=1-83,90, and 92, for He and Pm, at the Budapest Reactor. These data were evaluated with additional information from the literature to generate the Evaluated Gamma-ray Activation File (EGAF). Isotopic radiative neutron cross sections can be deduced from the total transition cross section feeding the

  16. Neutron sources for a neutron capture therapy facility

    SciTech Connect

    Lennox, A.J.

    1993-04-01

    Recent advances in the development of boron pharmaceuticals have reopened the possibility of using epithermal neutrons to treat brain tumors containing boron-10. This paper summarizes the approaches being used to generate the neutron sources and identifies specific areas where more research and development are needed.

  17. The thermal neutron capture cross section of the radioactive isotope $^{60}$Fe

    E-print Network

    Heftrich, T; Dressler, R; Eberhardt, K; Endres, A; Glorius, J; Göbel, K; Hampel, G; Heftrich, M; Käppeler, F; Lederer, C; Mikorski, M; Plag, R; Reifarth, R; Stieghorst, C; Schmidt, S; Schumann, D; Slavkovská, Z; Sonnabend, K; Wallner, A; Weigand, M; Wiehl, N; Zauner, S

    2015-01-01

    50% of the heavy element abundances are produced via slow neutron capture reactions in different stellar scenarios. The underlying nucleosynthesis models need the input of neutron capture cross sections. One of the fundamental signatures for active nucleosynthesis in our galaxy is the observation of long-lived radioactive isotopes, such as $^{60}$Fe with a half-life of $2.60\\times10^6$ yr. To reproduce this $\\gamma$-activity in the universe, the nucleosynthesis of $^{60}$Fe has to be understood reliably. A $^{60}$Fe sample produced at the Paul-Scherrer-Institut was activated with thermal and epithermal neutrons at the research reactor at the Johannes Gutenberg-Universit\\"at Mainz. The thermal neutron capture cross section has been measured for the first time to $\\sigma_{\\text{th}}=0.226 \\ (^{+0.044}_{-0.049})$ b. An upper limit of $\\sigma_{\\text{RI}} < 0.50$ b could be determined for the resonance integral. An extrapolation towards the astrophysicaly interesting energy regime between $kT$=10 keV and 100 ke...

  18. Exposure ages and neutron capture record in lunar samples from Fra Mauro.

    NASA Technical Reports Server (NTRS)

    Lugmair, G. W.; Marti, K.

    1972-01-01

    Cosmic-ray exposure ages of Apollo 14 rocks and rock fragments obtained by the Kr81-Kr83 method range from 27 to 700 m.y. Rock 14321, collected near the Cone crater rim, is one of the many approximately 27 m.y. old ejecta which were reported at the Third Lunar Science Conference. All the other rocks have considerably higher exposure ages. Isotopic anomalies from neutron capture in gadolinium, bromine, and barium are used to obtain information on the lunar neutron spectrum at various depths below the lunar surface. The flux ratio of resonance and slow (less than 0.3 eV) neutrons is found to be nearly constant in the topmost approximately 100 g/sq cm.

  19. Mixed field dosimetry of epithermal neutron beams for boron neutron capture therapy at the MITR-II research reactor

    Microsoft Academic Search

    Ronald D. Rogus; O. K. Harling; J. C. Yanch

    1994-01-01

    During the past several years, there has been growing interest in Boron Neutron Capture Therapy (BNCT) using epithermal neutron beams. The dosimetry of these beams is challenging. The incident beam is comprised mostly of epithermal neutrons, but there is some contamination from photons and fast neutrons. Within the patient, the neutron spectrum changes rapidly as the incident epithermal neutrons scatter

  20. Proceedings of the first international symposium on neutron capture therapy

    SciTech Connect

    Fairchild, R.G.; Brownell, G.L. (eds.)

    1982-01-01

    This meeting was arranged jointly by MIT and BNL in order to illuminate progress in the synthesis and targeting of boron compounds and to evaluate and document progress in radiobiological and dosimetric aspects of neutron capture therapy. It is hoped that this meeting will facilitate transfer of information between groups working in these fields, and encourage synergistic collaboration.

  1. Direct Neutron Capture Calculations with Covariant Density Functional Theory Inputs

    NASA Astrophysics Data System (ADS)

    Zhang, Shi-Sheng; Peng, Jin-Peng; Smith, Michael S.; Arbanas, Goran; Kozub, Ray L.

    2014-09-01

    Predictions of direct neutron capture are of vital importance for simulations of nucleosynthesis in supernovae, merging neutron stars, and other astrophysical environments. We calculate the direct capture cross sections for E1 transitions using nuclear structure information from a covariant density functional theory as input for the FRESCO coupled-channels reaction code. We find good agreement of our predictions with experimental cross section data on the double closed-shell targets 16O, 48Ca, and 90Zr, and the exotic nucleus 36S. Extensions of the technique for unstable nuclei and for large-scale calculations will be discussed. Predictions of direct neutron capture are of vital importance for simulations of nucleosynthesis in supernovae, merging neutron stars, and other astrophysical environments. We calculate the direct capture cross sections for E1 transitions using nuclear structure information from a covariant density functional theory as input for the FRESCO coupled-channels reaction code. We find good agreement of our predictions with experimental cross section data on the double closed-shell targets 16O, 48Ca, and 90Zr, and the exotic nucleus 36S. Extensions of the technique for unstable nuclei and for large-scale calculations will be discussed. Supported by the U.S. Dept. of Energy, Office of Nuclear Physics.

  2. Neutron capture by fissile and fertile actinide targets

    SciTech Connect

    Maslov, Vladimir M. [Joint Institute of Nuclear and Energy Research, 220109, Minsk (Belarus)

    2009-01-28

    For fissile actinide targets {sup 233}U, {sup 235}U and {sup 239}Pu the capture cross sections are strongly influenced by the target spin, fission transition states spectroscopy and fission/{gamma}-emission competition of the compound nuclides. The capture cross sections were obtained via a consistent description of fission and elastic/inelastic scattering, (n,{gamma}f) reaction being included.For neutron capture reactions on even-even U, Pu and Cm nuclei the methods, proven in case of {sup 232}Th(n,{gamma}) and {sup 238}U(n,{gamma}) data analysis are used. Calculated {sup 240}Pu(n,{gamma}) and {sup 244}Cm(n,{gamma}) reaction cross sections shapes are much similar to that, observed for the {sup 238}U(n,{gamma}) and {sup 232}Th(n,{gamma}) reactions. Differences are due to fission and neutron emission competition, which depends on the (Z,N)-composition of the compound nucleus.

  3. Anomalously large neutron capture cross sections: a random phenomenon?

    E-print Network

    Carlson, B V; Kerman, A K

    2015-01-01

    We discuss the existence of huge thermal neutron capture cross sections in several nuclei. The values of the cross sections are several orders of magnitude bigger than expected at these very low energies. We lend support to the idea that this phenomenon is random in nature and is similar to what we have learned from the study of parity violation in the actinide region. The idea of statistical doorways is advanced as a unified concept in the delineation of large numbers in the nuclear world. The average number of maxima per unit mass, $$ in the capture cross section is calculated and related to the underlying cross section correlation function and found to be $ = \\frac{3}{\\pi \\sqrt{2}\\gamma_{A}}$, where $\\gamma_{A}$ is a characteristic mass correlation width which designates the degree of remnant coherence in the system. We trace this coherence to nucleosynthesis which produced the nuclei whose neutron capture cross sections are considered here.

  4. [Liposomal boron delivery system for neutron capture therapy].

    PubMed

    Nakamura, Hiroyuki

    2008-02-01

    Boron neutron capture therapy (BNCT) is a binary cancer treatment based on the nuclear reaction of two essentially nontoxic species, (10)B and thermal neutrons. High accumulation and selective delivery of boron into tumor tissue are the most important requirements to achieve efficient neutron capture therapy of cancers. This review focuses on the liposomal boron delivery system (BDS) as a recent promising approach that meets these requirements for BNCT. BDS involves two strategies: (1) encapsulation of boron in the aqueous core of liposomes and (2) accumulation of boron in the liposomal bilayer. Various boronated liposomes have been developed and significant boron accumulation into tumor tissue with high tumor/blood boron ratios has been achieved by BDS. PMID:18239367

  5. Neutron capture measurements on unstable nuclei at LANSCE

    SciTech Connect

    Ullmann, J.L.; Haight, R.C. [LANSCE-3, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Fowler, M.M.; Miller, G.G.; Rundberg, R.S.; Wilhelmy, J.B. [CST-11, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    1999-06-01

    Although neutron capture by stable isotopes has been extensively measured, there are very few measurements on unstable isotopes. The intense neutron flux at the Manual Lujan Jr. Neutron Scattering Center at LANSCE enables us to measure capture on targets with masses of about 1 mg over the energy range from 1 eV to 100 keV. These measurements are important not only for understanding the basic physics, but also for calculations of stellar nucleosynthesis and Science-Based Stockpile Stewardship. Preliminary measurements on {sup 169}Tm and {sup 171}Tm have been made with deuterated benzene detectors. A new detector array at the Lujan center and a new radioactive isotope separator will combine to give Los Alamos a unique capability for making these measurements. {copyright} {ital 1999 American Institute of Physics.}

  6. Neutron capture measurements on unstable nuclei at LANSCE

    SciTech Connect

    Ullmann, J. L.; Haight, R. C.; Fowler, M. M.; Miller, G. G.; Rundberg, R. S.; Wilhelmy, J. B. [LANSCE-3, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); CST-11, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    1999-06-10

    Although neutron capture by stable isotopes has been extensively measured, there are very few measurements on unstable isotopes. The intense neutron flux at the Manual Lujan Jr. Neutron Scattering Center at LANSCE enables us to measure capture on targets with masses of about 1 mg over the energy range from 1 eV to 100 keV. These measurements are important not only for understanding the basic physics, but also for calculations of stellar nucleosynthesis and Science-Based Stockpile Stewardship. Preliminary measurements on {sup 169}Tm and {sup 171}Tm have been made with deuterated benzene detectors. A new detector array at the Lujan center and a new radioactive isotope separator will combine to give Los Alamos a unique capability for making these measurements.

  7. Neutron beam optimization for boron neutron capture therapy using the D-D and DT high-energy neutron sources

    Microsoft Academic Search

    J. M. Verbeke; J. L. Vujic; K. N. Leung

    2000-01-01

    A monoenergetic neutron beam simulation study is carried out to determine the most suitable neutron energy for treatment of shallow and deep-seated brain tumors in the context of boron neutron capture therapy. Two figures-of-merit--the absorbed skin dose and the absorbed tumor dose at a given depth in the brain--are used to measure the neutron beam quality. Based on the results

  8. General Electric PETtrace cyclotron as a neutron source for boron neutron capture therapy

    Microsoft Academic Search

    Andrey Bosko

    2005-01-01

    This research investigates the use of a PETtrace cyclotron produced by General Electric (GE) as a neutron source for boron neutron capture therapy (BNCT). The GE PETtrace was chosen for this investigation because this type of cyclotron is popular among nuclear pharmacies and clinics in many countries; it is compact and reliable; it produces protons with energies high enough to

  9. An integrated design of an accelerator-based neutron source for boron neutron capture therapy

    Microsoft Academic Search

    Michael Christian Dobelbower

    1997-01-01

    An Accelerator Based Neutron Source (ABNS) for Boron Neutron Capture Therapy (BNCT) was first proposed at The Ohio State University (OSU). Since the conception of the ABNS for BNCT, OSU has designed and optimized a moderator assembly based on in-air and in-phantom parameters. Additionally, the fabrication of the moderator assembly has commenced along with detailed analyses of the target and

  10. An improved neutron collimator for brain tumor irradiations in clinical boron neutron capture therapy

    Microsoft Academic Search

    Hungyuan B. Liu; D. D. Greenberg; J. Capala; F. J. Wheeler

    1996-01-01

    To improve beam penetration into a head allowing the treatment of deeper seated tumors, two neutron collimators were built sequentially and tested for use in the clinical boron neutron capture therapy (BNCT) program at the epithermal neutron irradiation facility of the Brookhaven Medical Research Reactor. The collimators were constructed from lithium-impregnated polyethylene, which comprises LiâCOâ powder (â93% enriched isotopic ⁶Li)

  11. Accelerator-based epithermal neutron sources for boron neutron capture therapy of brain tumors

    Microsoft Academic Search

    Thomas E. Blue; Jacquelyn C. Yanch

    2003-01-01

    Summary  This paper reviews the development of low-energy light ion accelerator-based neutron sources (ABNSs) for the treatment of\\u000a brain tumors through an intact scalp and skull using boron neutron capture therapy (BNCT). A major advantage of an ABNS for\\u000a BNCT over reactor-based neutron sources is the potential for siting within a hospital. Consequently, light-ion accelerators\\u000a that are injectors to larger machines

  12. Accelerator-based Epithermal Neutron Sources for Boron Neutron Capture Therapy of Brain Tumors

    Microsoft Academic Search

    Thomas E. Blue; Jacquelyn C. Yanch

    2003-01-01

    This paper reviews the development of low-energy light ion accelerator-based neutron sources (ABNSs) for the treatment of brain tumors through an intact scalp and skull using boron neutron capture therapy (BNCT). A major advantage of an ABNS for BNCT over reactor-based neutron sources is the potential for siting within a hospital. Consequently, light-ion accelerators that are injectors to larger machines

  13. Conceptual design of an RFQ accelerator-based neutron source for boron neutron-capture therapy

    Microsoft Academic Search

    T. P. Wangler; J. E. Stovall; T. S. Bhatia; C. K. Wang; T. E. Blue; R. A. Gahbauer

    1989-01-01

    A conceptual design of a low-energy neutron generator for treatment of brain tumors by boron neutron capture therapy (BNCT) is presented. The concept is based on a 2.5-MeV proton beam from a radio-frequency quadrupole (RFQ) linac, and the neutrons are produced by the 7Li(p,n)7Be reaction. A liquid lithium target and modulator assembly are designed to provide a high flux of

  14. A shielding design for an accelerator-based neutron source for boron neutron capture therapy

    Microsoft Academic Search

    A. E Hawk; T. E Blue; J. E Woollard

    2004-01-01

    Research in boron neutron capture therapy (BNCT) at The Ohio State University Nuclear Engineering Department has been primarily focused on delivering a high quality neutron field for use in BNCT using an accelerator-based neutron source (ABNS). An ABNS for BNCT is composed of a proton accelerator, a high-energy beam transport system, a 7Li target, a target heat removal system (HRS),

  15. Accelerator-based neutron source for the neutron-capture and fast neutron therapy at hospital

    NASA Astrophysics Data System (ADS)

    Bayanov, B. F.; Belov, V. P.; Bender, E. D.; Bokhovko, M. V.; Dimov, G. I.; Kononov, V. N.; Kononov, O. E.; Kuksanov, N. K.; Palchikov, V. E.; Pivovarov, V. A.; Salimov, R. A.; Silvestrov, G. I.; Skrinsky, A. N.; Soloviov, N. A.; Taskaev, S. Yu.

    The proton accelerator complex for neutron production in lithium target discussed, which can operate in two modes. The first provides a neutron beam kinematically collimated with good forward direction in 25° and average energy of 30 keV, directly applicable for neutron-capture therapy with high efficiency of proton beam use. The proton energy in this mode is 1.883-1.890 MeV that is near the threshold of the 7Li( p, n) 7Be reaction. In the second mode, at proton energy of 2.5 MeV, the complex-produced neutron beam with maximum energy board of 790 keV which can be used directly for fast neutron therapy and for neutron-capture therapy after moderation. The project of such a neutron source is based on the 2.5 MeV original electrostatic accelerator tandem with vacuum insulation developed at BINP which is supplied with a high-voltage rectifier. The rectifier is produced in BINP as a part of ELV-type industrial accelerator. Design features of the tandem determining its high reliability in operation with a high-current (up to 40 mA) H - ion beam are discussed. They are: the absence of ceramic accelerator columns around the beam passage region, good conditions for pumping out of charge-exchange gaseous target region, strong focusing optics and high acceleration rate minimizing the space charge effects. The possibility of stabilization of protons energy with an accuracy level of 0.1% necessary for operation in the near threshold region is considered. The design description of H - continuous ion source with a current of 40 mA is also performed. To operate with a 100 kW proton beam it is proposed to use liquid-lithium targets. A thin lithium layer on the surface of a tungsten disk cooled intensively by a liquid metal heat carrier is proposed for use in case of the vertical beam, and a flat liquid lithium jet flowing through the narrow nozzle - for the horizontal beam.

  16. Three-port beam splitter for slow neutrons using holographic nanoparticle-polymer composite diffraction gratings

    SciTech Connect

    Klepp, J.; Fally, M. [Faculty of Physics, University of Vienna, 1090 Wien (Austria); Tomita, Y. [Department of Engineering Science, University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182 (Japan); Pruner, C. [Department of Materials Science and Physics, University of Salzburg, 5020 Salzburg (Austria); Kohlbrecher, J. [Laboratory for Neutron Scattering, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland)

    2012-10-08

    Diffraction of slow neutrons by nanoparticle-polymer composite gratings has been observed. By carefully choosing grating parameters such as grating thickness and spacing, a three-port beam splitter operation for slow neutrons - splitting the incident neutron intensity equally into the {+-}1st and the 0th diffraction orders - has been realized. As a possible application, a Zernike three-path interferometer is briefly discussed.

  17. Misassigned neutron resonances of 142Nd and stellar neutron capture cross sections

    NASA Astrophysics Data System (ADS)

    Katabuchi, Tatsuya; Matsuhashi, Taihei; Terada, Kazushi; Igashira, Masayuki; Mizumoto, Motoharu; Hirose, Kentaro; Kimura, Atsushi; Iwamoto, Nobuyuki; Hara, Kaoru Y.; Harada, Hideo; Hori, Jun-ichi; Kamiyama, Takashi; Kino, Koichi; Kitatani, Fumito; Kiyanagi, Yoshiaki; Nakamura, Shoji; Toh, Yosuke

    2015-03-01

    Time-of-flight spectra of the neutron capture events of 142Nd were measured using a spallation neutron source at the Japan Proton Accelerator Research Complex. The first six resonances of 142Nd reported in a previous work were not observed. The experimental results and cross-search of resonance energies in nuclear data libraries suggested that resonances of the impurity nuclide 141Pr have been mistakenly assigned as 142Nd in the previous experiment. To investigate the impact of the nonexistence of the resonances on the s -process nucleosynthesis model, the Maxwellian averaged neutron capture cross sections with and without the misassigned resonances were compared.

  18. Backgrounds from Neutron Capture in the NPDGamma Experiment

    NASA Astrophysics Data System (ADS)

    Kucuker Dogan, Serpil; NPDGamma Collaboration

    2013-10-01

    The NPDGamma experiment, which measures the parity-violating directional gamma asymmetry in neutron-proton capture, completed its second run cycle in May 2013 at the Fundamental Neutron Physics Beamline at the Oak Ridge Spallation Neutron Source. In the experiment an intense polarized low-energy neutron beam interacts with a liquid para-hydrogen target. Gamma rays from the capture reaction are detected by 48 CsI(Tl) current mode detectors with the 3° acceptance angle. The goal of the experiment is to measure the asymmetry with precision of 1 ×10-8 . The polarized neutrons also interact with other materials in beam, such as the beam windows and the walls of the target vessel producing a background to the signal that dilutes the PV gamma asymmetry. These materials could, in principle, have their own PV asymmetries. The Aluminum contribution in the background is the most significant, contributing about 20% of the total signal. We have studied the backgrounds and identified their sources and the strengths. I will discuss the methods to determine the backgrounds and their effect on NPDGamma.

  19. Neutron Capture Measurements at the n lowbar TOF Facility

    SciTech Connect

    Milazzo, P. M.; Abbondanno, U.; Fujii, K. [Istituto Nazionale di Fisica Nucleare, Trieste (Italy); Aerts, G.; Andriamonje, S.; Berthoumieux, E.; Dridi, W.; Ferrant, L.; Gunsing, F.; Pancin, J.; Perrot, L.; Plukis, A.; Stephan, C.; Tassan-Got, L. [Centre National de la Recherche Scientifique/IN2P3-IPN, Orsay (France); Alvarez, H.; Duran, I.; Paradela, C. [Universidade de Santiago de Compostela (Spain); Alvarez-Velarde, F.; Cano-Ott, D.; Embid-Segura, M. [Centro de Investigaciones Energeticas Medioambientales y Technologicas, Madrid (Spain)] (and others)

    2009-03-31

    Nuclear astrophysics, advanced nuclear technology and nuclear structure physics present many cases that require neutron capture reaction data with high precision. In particular, refined data are needed for stellar nucleosynthesis, for nuclear waste transmutation studies, and for the design of generation IV reactors. The measurements take profit of the pulsed neutron beam of the n lowbar TOF facility at CERN, which is generated by proton-induced spallation reactions on a massive lead target. The low repetition rate of the proton beam, the high instantaneous neutron flux, and the favourable background conditions in the experimental area make this facility unique for high resolution time-of-flight measurements of neutron induced reaction cross sections. The n lowbar TOF collaboration is presently operating two different experimental set-ups. The first consists of two low-neutron sensitivity C{sub 6}D{sub 6} detectors with the analysis relying on the Pulse Height Weighting technique. In addition, a Total Absorption Calorimeter, consisting of 40 BaF{sub 2} crystals covering the whole solid angle, was used. A review of several capture measurements with these detectors on selected stable and unstable samples will be presented.

  20. Target studies for accelerator-based boron neutron capture therapy

    SciTech Connect

    Powell, J.R.; Ludewig, H.; Todosow, M.; Reich, M.

    1996-03-01

    Two new concepts, NIFTI and DISCOS, are described. These concepts enable the efficient production of epithermal neutrons for BNCT (Boron Neutron Capture Therapy) medical treatment, utilizing a low current, low energy proton beam impacting on a lithium target. The NIFTI concept uses an iron layer that strongly impedes the transmission of neutrons with energies above 24 KeV. Lower energy neutrons readily pass through this iron ``filter``, which has a deep ``window`` in its scattering cross section at 24 KeV. The DISCOS concept uses a rapidly rotating, high g disc to create a series of thin ({approximately} 1 micron thickness) liquid lithium targets in the form of continuous films through which the proton beam passes. The average energy lost by a proton as it passes through a single target is small, approximately 10 KeV. Between the targets, the proton beam is reaccelerated by an applied DC electric field. The DISCOS approach enables the accelerator -- target facility to operate with a beam energy only slightly above the threshold value for neutron production -- resulting in an output beam of low-energy epithermal neutrons -- while achieving a high yield of neutrons per milliamp of proton beam current.

  1. Neutron radiative capture methods for surface elemental analysis

    USGS Publications Warehouse

    Trombka, J.I.; Senftle, F.; Schmadebeck, R.

    1970-01-01

    Both an accelerator and a 252Cf neutron source have been used to induce characteristic gamma radiation from extended soil samples. To demonstrate the method, measurements of the neutron-induced radiative capture and activation gamma rays have been made with both Ge(Li) and NaI(Tl) detectors, Because of the possible application to space flight geochemical analysis, it is believed that NaI(Tl) detectors must be used. Analytical procedures have been developed to obtain both qualitative and semiquantitative results from an interpretation of the measured NaI(Tl) pulse-height spectrum. Experiment results and the analytic procedure are presented. ?? 1970.

  2. Research in Boron Neutron Capture Therapy at MIT LABA

    NASA Astrophysics Data System (ADS)

    Yanch, J. C.; Shefer, R. E.; Klinkowstein, R. E.; Howard, W. B.; Song, H.; Blackburn, B.; Binello, E.

    1997-02-01

    A 4.1 MeV tandem electrostatic accelerator designed for research into Boron Neutron Capture Therapy (BNCT) has recently been installed in the MIT Laboratory for Accelerator Beam Applications (LABA). This accelerator uses a very high current switch mode high voltage power supply in conjunction with a multi-cusp negative ion source to supply the multimilliampere current required for clinical BNCT applications. A number of individual research projects aimed at evaluating the potential of this accelerator design as a hospital-based neutron source for radiation therapy of both tumors and rheumatoid arthritis are described here.

  3. Influences of Neutron Source Spectrum and Thermal Neutron Scattering Law Data on the MCNPX Simulation of a Cyclotron-Based Neutron Field for Boron Neutron Capture Therapy

    Microsoft Academic Search

    Shunsuke YONAI; Mamoru BABA; Toshiro ITOGA; Takashi NAKAMURA; Hitoshi YOKOBORI; Yoshihisa TAHARA

    2007-01-01

    In our previous study, the simulation of a cyclotron-based neutron field for boron neutron capture therapy (BNCT) using a (p,n) spallation source with the MCNPX code was validated through measurements of the neutron energy spectrum behind the moderator assembly and the thermal neutron distribution in an acrylic phantom using reaction rates of Au. These validations showed that the simulation generally

  4. Informing Neutron-Capture Rates through (d,p) Reactions on Neutron-Rich Tin Isotopes

    NASA Astrophysics Data System (ADS)

    Manning, B.; Cizewski, J. A.; Kozub, R. L.; Ahn, S.; Allmond, J. M.; Bardayan, D. W.; Chae, K. Y.; Chipps, K. A.; Howard, M. E.; Jones, K. L.; Liang, J. F.; Matos, M.; Nunes, F. M.; Nesaraja, C. D.; O'Malley, P. D.; Pain, S. D.; Peters, W. A.; Pittman, S. T.; Ratkiewicz, A.; Schmitt, K. T.; Shapira, D.; Smith, M. S.; Titus, L.

    2014-03-01

    Level energies and spectroscopic information for neutron-rich nuclei provide important input for r-process nucleosynthesis calculations; specifically, the location and strength of single-neutron l = 1 states when calculating neutron-capture rates. Surman and collaborators have performed sensitivity studies to show that varying neutron-capture rates can significantly alter final r-process abundances. However, there are many nuclei important to the r-process that cannot be studied. Extending studies to more neutron-rich nuclei will help constrain the nuclear shell-model in extrapolating to nuclei even further from stability. The (d,p) reaction has been measured with radioactive ion beams of 126Sn and 128Sn to complete the set of (d,p) studies on even mass tin isotopes from doubly-magic 132 to stable 124Sn. Work supported in part by the U.S. Department of Energy and National Science Foundation.

  5. Validating (d,p?) as a Surrogate for Neutron Capture

    NASA Astrophysics Data System (ADS)

    Ratkiewicz, A.; Cizewski, J. A.; Pain, S. D.; Adekola, A. S.; Burke, J. T.; Casperson, R. J.; Fotiades, N.; McCleskey, M.; Burcher, S.; Shand, C. M.; Austin, R. A. E.; Baugher, T.; Carpenter, M. P.; Devlin, M.; Escher, J. E.; Hardy, S.; Hatarik, R.; Howard, M. E.; Hughes, R. O.; Jones, K. L.; Kozub, R. L.; Lister, C. J.; Manning, B.; O'Donnell, J. M.; Peters, W. A.; Ross, T. J.; Scielzo, N. D.; Seweryniak, D.; Zhu, S.

    2015-05-01

    The r-process is responsible for creating roughly half of the elements heavier than iron. It has recently become understood that the rates at which neutron capture reactions proceed at late times in the r-process may dramatically affect the final abundance pattern. However, direct measurements of neutron capture reaction rates on exotic nuclei are exceptionally difficult, necessitating the development of indirect approaches such as the surrogate technique. The (d,p?) reaction at low energies was identified as a promising surrogate for the (n,?) reaction, as both reactions share many characteristics. We report on a program to validate (d,p?) as a surrogate for (n,?) using 95Mo as a target. The experimental campaign includes direct measurements of the ?-ray intensities from the decay of excited states populated in the 95Mo(n,?) and 95Mo(d,p?) reactions.

  6. Impact of the phonon coupling on the radiative neutron capture

    SciTech Connect

    Avdeenkov, A. V. [Stellenbosch Institute of Advanced Study, National Institute for Theoretical Physics (South Africa); Goriely, S. [Institute d'Astronomie et d'Astrophysique (Belgium); Kamerdzhiev, S. P. [Institute of Physics and Power Engineering (Russian Federation)

    2010-07-15

    Inclusion of the coupling of quasiparticle degrees of freedom with phonon degrees is a natural extention of the standard QRPA approach. The paper presents the quantitative impact of this phonon coupling on the dipole strength and radiative neutron capture for the stable {sup 124}Sn and very exotic {sup 150}Sn isotopes, as an illustration, using the self-consistent version of the Extended Theory of Finite Fermi Systems. It was found that the phonon contribution to the pygmy-dipole resonance and radiative neutron capture cross section is increased with the (N - Z) difference growth. The results show that the self-consistent nuclear structure calculations are important for unstable nuclei, where phenomenological approaches do not work.

  7. Neutron capture cross section and capture gamma-ray spectra of 138Ba in the keV-neutron energy region

    NASA Astrophysics Data System (ADS)

    Katabuchi, T.; Yanagida, S.; Terada, K.; Iwamoto, N.; Igashira, M.

    2015-05-01

    The neutron capture cross sections and the capture ?-ray spectra of 138Ba were measured in the astrophysically important energy region. Measurements were made at neutron energies from 15 to 80 keV. The neutron energy was determined by the time-of-flight method. The ?-ray spectra showed that the primary transition pattern strongly depended on the incident neutron energy. The neutron capture cross sections were derived by the pulse height weighting technique. The present cross section values were compared with evaluated cross section data and previous measurements.

  8. Stellar neutron capture cross sections of the Gd isotopes

    NASA Astrophysics Data System (ADS)

    Wisshak, K.; Voss, F.; Käppeler, F.; Guber, K.; Kazakov, L.; Kornilov, N.; Uhl, M.; Reffo, G.

    1995-11-01

    The neutron capture cross sections of 152Gd, 154Gd, 155Gd, 156Gd, 157Gd, and 158Gd were measured in the energy range from 3 to 225 keV at the Karlsruhe 3.75 MV Van de Graaff accelerator. Neutrons were produced via the 7Li(p,n)7Be reaction by bombarding metallic Li targets with a pulsed proton beam. Capture events were registered with the Karlsruhe 4? Barium Fluoride Detector, which was improved by replacing crystals with high ? background and by introducing a pierced crystal at zero degrees with respect to the beam axis. These changes resulted in a significantly increased efficiency for capture events. The main experimental problem was that the samples of the two s isotopes 152Gd and 154Gd showed only relatively low enrichment. Nevertheless, the spectroscopic quality of the BaF2 detector allowed evaluation of the corresponding corrections for isotopic impurities reliably. The cross section ratios could be determined with an overall uncertainty of typically 1%, an improvement by factors of five to ten compared to existing data. Severe discrepancies were found with respect to previous results. Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT=10 keV and 100 keV. The new stellar cross sections were used for an updated analysis of the s-process reaction flow in the mass region between samarium and gadolinium, which is characterized by branchings at 151Sm, 154Eu, and 155Eu. With the classical approach, the s-process temperature could be constrained corresponding to a range of thermal energies between kT=28 and 33 keV. The 152Gd production in low mass stars was found to depend strongly on the neutron freeze-out at the end of the helium shell burning episodes.

  9. Stellar neutron capture cross sections of the Lu isotopes

    SciTech Connect

    Wisshak, K.; Voss, F.; Kaeppeler, F.; Kazakov, L. [Forschungszentrum Karlsruhe, Institut fuer Kernphysik, Postfach 3640, D-76021 Karlsruhe (Germany); Institute for Physics and Power Engineering, Obninsk, Kaluga-Region (Russian Federation)

    2006-01-15

    The neutron capture cross sections of {sup 175}Lu and {sup 176}Lu have been measured in the energy range 3-225 keV at the Karlsruhe 3.7 MV Van de Graaff accelerator. Neutrons were produced via the {sup 7}Li(p,n){sup 7}Be reaction by bombarding metallic Li targets with a pulsed proton beam, and capture events were registered with the Karlsruhe 4{pi} barium fluoride detector. The cross sections were determined relative to the gold standard using isotopically enriched as well as natural lutetium oxide samples. Overall uncertainties of {approx}1% could be achieved in the final cross section ratios to the gold standard, about a factor of 5 smaller than in previous works. Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT = 8 and 100 keV. These values are systematically larger by {approx}7% than those reported in recent evaluations. These results are of crucial importance for the assessment of the s-process branchings at A 175/176.

  10. High-current electrostatic accelerator for boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Shefer, Ruth E.; Klinkowstein, Robert E.; Yanch, Jacquelyn C.

    1997-02-01

    The use of boron neutron capture therapy in clinical treatment will require the development of intense neutron sources suitable for operation in a hospital environment. Low-energy accelerator-based neutron sources have the potential for meeting the requirements for a clinical BNCT facility. This paper describes the design, installation, and initial operation of the first high current tandem accelerator for this application. The accelerator utilizes a highly power efficient switch-mode high voltage generator to deliver proton beams with energies of up to 4.1 MeV. The use of a multi-cusp high current negative ion source in combination with magnetically suppressed accelerating tubes allows the acceleration of proton beam currents up to 4 mA. The design principles and operation of the accelerator are described.

  11. Neutron capture cross section measurement of 20,22Ne for stellar nucleosynthesis

    Microsoft Academic Search

    A. Tomyo; Y. Nagai; Y. Nobuhara; T. Shima; H. Makii; K. Mishima; M. Igashira

    2003-01-01

    We have measured the neutron capture cross sections of 20Ne(n,?)21Ne and 22Ne(n,?)23Ne at stellar energy by detecting a discrete ?-ray feeding from a neutron capturing state to a low-lying state. In this work the non-resonant direct p-wave capture reaction process has been identified for the first time in the keV neutron capture reactions of Ne isotopes.

  12. Non-reactor neutron sources for BNCT (Boron Neutron Capture Therapy)

    SciTech Connect

    Dolan, T.J.; Ottewitte, E.H.; Wills, E.E.; Neuman, W.A.; Woodall, D.M.

    1989-05-01

    The focus of this study is the indentification of key feasibility issues for the use of non-reactor neutron sources for Boron Neutron Capture Therapy (BNCT). Of the non-reactor neutron sources surveyed, the /sup 7/Li(p,n) reaction appears to be the most favorable for producing epithermal neutrons for BNCT, and RFQ accelerators are best for producing the desired proton beam. At a proton energy of 2.5 MeV, the total neutron yield is 1.49 /times/ 10/sup /minus/4/ neutrons/proton, with a forward energy spectrum extending up to 780 keV and peaked at 500-600 keV. At I = 20 mA, the total neutron yield would be about 1.86 /times/ 10/sup 13/ neutrons/s. In comparison with a medical therapy fission reactor, the 20 mA accelerator system has a flux intensity at least 5 times lower, requiring an irradiation time at least 5 times longer, a much higher gamma intensity, which would probably require additional shielding, further reducing the neutron intensity, 30% of the neutrons above 15 keV, resulting in a higher fast neutron dose to healthy tissue, poorer spatial uniformity of the neutron beam, and greater angular divergence of the neutron beam, resulting in a rapid decrease of flux with distance from the filter. The possibility of overcoming these limitations by using more shielding and a higher beam current needs further study. RFQ accelerator technology is being developed to provide the desired proton beam parameters. The effects of neutron beam energy spectra, beam contaminants, angular divergence, spatial variation, and beam rotation around the tumor need to be studied in detail, in order to evaluate the feasibility of accelerator-produced neutrons for BNCT. 41 refs., 20 figs., 8 tabs.

  13. Hafnium Resonance Parameter Analysis using Neutron Capture and Transmission Experiments

    NASA Astrophysics Data System (ADS)

    Trbovich, Michael J.; Barry, Devin P.; Slovacek, Rudy E.; Danon, Yaron; Block, Robert C.; Burke, John A.; Drindak, Noel J.; Leinweber, Greg; Ballad, Robert V.

    2005-05-01

    The focus of this work is to determine resonance parameters for stable hafnium isotopes in the 0.005-200 eV region, with special emphasis on the overlapping 176Hf and 178Hf resonances near 8 eV. The large neutron cross section of hafnium, combined with its corrosion resistance and excellent mechanical properties, make it a useful material for controlling nuclear reactions. Experiments measuring neutron capture and transmission were performed at the Rensselaer Polytechnic Institute (RPI) electron linear accelerator (LINAC) using the time of flight method. 6Li glass scintillation detectors were used for transmission experiments at flight path lengths of 15 and 25 m. Capture experiments were done using a sixteen-section NaI(Tl) multiplicity detector at a flight path length of 25 m. These experiments utilized various thicknesses of metallic and isotopically enriched liquid samples. The liquid samples were designed to provide information on the 176Hf and 178Hf contributions to the 8-eV doublet without saturation. Data analysis was done using the R-matrix Bayesian code SAMMY version M6 beta. SAMMY is able to account for experimental resolution effects for each of the experimental setups at the RPI LINAC, and also can correct for multiple scattering effects in neutron capture yield data. The combined capture and transmission data analysis yielded resonance parameters for all hafnium isotopes from 0.005-200 eV. Resonance integrals were calculated along with errors for each hafnium isotope using the NJOY and INTER codes. The isotopic resonance integrals calculated were significantly different than previously published values; however the calculated elemental hafnium resonance integral changed very little.

  14. Stellar neutron capture cross sections of the Gd isotopes.

    NASA Astrophysics Data System (ADS)

    Wisshak, K.; Voss, F.; Käppeler, F.; Guber, K.; Kazakov, L.; Kornilov, N.; Uhl, M.; Reffo, G.

    1995-05-01

    The neutron capture cross sections of 152Gd, 154Gd, 155Gd, 156Gd, 157Gd, and 158Gd were measured in the energy range from 3 to 225 keV at the Karlsruhe 3.75 MV Van de Graaff accelerator. Neutrons were produced via the 7Li(p, n)7Be reaction by bombarding metallic Li targets with a pulsed proton beam. Capture events were registered with the Karlsruhe 4? Barium Fluoride Detector The main experimental problem was that the samples of the two s-only isotopes 152Gd and 154Gd showed only relatively low enrichment, but the spectroscopic quality of the BaF2 detector allowed to determine the resulting corrections for isotopic impurities reliably. The cross section ratios could be determined with an overall uncertainty of typically 1%, an improvement by factors of five to ten compared to existing data. Severe discrepancies were found with respect to previous results. Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT = 10 keV and 100 keV. The new stellar cross sections were used for an updated analysis of the s-process reaction flow in the mass region between samarium and gadolinium, which is characterized by branchings at 151Sm, 154Eu, and 155Eu. With the classical approach, the s-process temperature could be constrained corresponding to a range of thermal energies between kT - 28 keV and 33 keV. The 152Gd production in low mass stars was found to depend strongly on the neutron freeze-out at the end of the helium shell burning episodes.

  15. Prompt response self-powered neutron detectors. 1: The effective charge per neutron captured

    Microsoft Academic Search

    M. D. C. Lopes; J. M. Avila

    1987-01-01

    A simple, physically transparent method is developed to calculate the electric charge per neutron captured in prompt response self-powered neutron detectors (SPNDs), which contributes to the emitter-collector current. This charge is written as the energy integral of the product of two functions: the spectral function S(E), which is the energy spectrum of all electrons resulting from prompt gamma interactions with

  16. In-hospital neutron autoradiography for Boron Neutron Capture Therapy applications

    Microsoft Academic Search

    A. Mattera; D. Bolognini; S. Hasan; M. Prest; E. Vallazza; G. Giannini; P. Cappelletti; M. Frigerio; S. Gelosa; A. F. Monti; A. Ostinelli; P. Mauri; F. Basilico; A. Zanini; E. Capelli; P. Chiari; P. Borasio

    Boron Neutron Capture Therapy (BNCT) is an experimental radiotherapy technique exploiting the reaction 10B(n,?)7Li to deliver a dose to the tumor sparing the healthy tissues: dedicated molecules are used to introduce the boron selectively\\u000a in the tumor cells, which are irradiated with a thermal-epithermal neutron beam. There are two main limitations preventing\\u000a BNCT from becoming a large-scale therapy: the availability

  17. New horizons for therapy based on the boron neutron capture reaction.

    PubMed

    Hawthorne, M F

    1998-04-01

    Boron neutron capture therapy (BNCT) is currently undergoing clinical trials in the USA, Japan and The Netherlands with patients afflicted with deadly brain cancer (glioblastoma multiforme) or melanoma. This therapy relies on a binary process in which the capture of a slow neutron by a 10B nucleus leads to an energetic nuclear fission reaction, with the formation of 7Li3+ and 4He2+ and accompanied by about 2.4 MeV of energy. The fleeting 7Li3+ and 4He2+ travel a distance of only about the diameter of one cell, and they are deadly to any cell in which they have been produced. Research in progress is concerned with the development of advanced boron agents and neutron sources, other than nuclear reactors, for the treatment of a variety of cancer types using novel 10B delivery methods. Non-malignant diseases such as rheumatoid arthritis offer additional opportunities for BNCT. The entire BNCT area awaits commercialization. PMID:9572059

  18. Reaction rates for Neutron Capture Reactions to C-, N- and O-isotopes to the neutron rich side of stability

    E-print Network

    H. Herndl; R. Hofinger; J. Jank; H. Oberhummer; J. Goerres; M. Wiescher; F. -K. Thielemann; B. A. Brown

    1999-08-31

    The reaction rates of neutron capture reactions on light nuclei are important for reliably simulating nucleosynthesis in a variety of stellar scenarios. Neutron capture reaction rates on neutron-rich C-, N-, and O-isotopes are calculated in the framework of a hybrid compound and direct capture model. The results are tabulated and compared with the results of previous calculations as well as with experimental results.

  19. Nuclear data sensitivities and the rapid neutron capture process

    NASA Astrophysics Data System (ADS)

    Mumpower, Matthew

    2015-04-01

    Simulations of the rapid neutron capture or r process of nucleosynthesis require the input of thousands of pieces of nuclear data for which no experimental information is available. These uncertain nuclear quantities are coupled, for instance, nuclear masses effect r-process abundances by entering into calculations of Q-values, neutron capture rates, photo-dissociation rates, ?-decay rates and the probability to emit neutrons. We report on our recent studies of nuclear data sensitivities in the r process. These studies take into account the propagation of uncertainties to properly identify individual nuclei that influence r-process abundances over a range of nuclear models and astrophysical conditions. We additionally explore the impact of uncertainties in nuclear data on the r process by performing global Monte Carlo simulations. We conclude that the reduction of nuclear data uncertainties either by new measurements or by improved nuclear models will allow for more robust r-process predictions. This work was supported by the Joint Institute for Nuclear Astrophysics Grant Number PHY0822648.

  20. Optimization of a moderator assembly for use in an accelerator-based neutron source for boron neutron capture therapy

    Microsoft Academic Search

    Jeffrey Earl Woollard

    1997-01-01

    In this dissertation, the development and application of in-phantom neutron field optimization parameters for use in evaluating neutron fields for Boron Neutron Capture Therapy (BNCT) is presented. These parameters are based on dose rate distributions in a head phantom and include the effects of fractionation and an energy dependent normal-tissue neutron RBE. As a step in the development of these

  1. Designing accelerator-based epithermal neutron beams for boron neutron capture therapy

    Microsoft Academic Search

    D. L. Bleuel; R. J. Donahue; B. A. Ludewigt; J. Vujic

    1998-01-01

    The ⁷Li(p,n)⁷Be reaction has been investigated as an accelerator-driven neutron source for proton energies between 2.1 and 2.6 MeV. Epithermal neutron beams shaped by three moderator materials, Al\\/AlFâ, ⁷LiF, and DâO, have been analyzed and their usefulness for boron neutron capture therapy (BNCT) treatments evaluated. Radiation transport through the moderator assembly has been simulated with the Monte Carlo {ital N}-particle

  2. Neutron Capture Measurements and Resonance Analysis of Dysprosium Y.R. Kang,1

    E-print Network

    Danon, Yaron

    Neutron Capture Measurements and Resonance Analysis of Dysprosium Y.R. Kang,1 M.W. Lee,1 T.I. Ro,2 The electron linear accelerator facility at the Rensselaer Polytechnic Institute was used to measure neutron capture yields of dysprosium with the time-of-flight method in the neutron energy region from 10 eV to 1

  3. Accelerator-based neutron source for boron neutron capture therapy (BNCT) and method

    Microsoft Academic Search

    W. Y. Yoon; J. L. Jones; D. W. Nigg; Y. D. Harker

    1999-01-01

    A source for boron neutron capture therapy (BNCT) comprises a body of photoneutron emitter that includes heavy water and is closely surrounded in heat-imparting relationship by target material; one or more electron linear accelerators for supplying electron radiation having energy of substantially 2 to 10 MeV and for impinging such radiation on the target material, whereby photoneutrons are produced and

  4. Real-time dosimetry for boron-neutron capture therapy

    SciTech Connect

    Bliss, M.; Craig, R.A.; Reeder, P.L.; Sunberg, D.S.

    1994-09-01

    Epithermal/thermal boron neutron-capture therapy (BNCT) is promising treatment method for malignant tumors. Because the doses and dose rates for medical therapeutic radiation are very close to the normal tissue tolerance, small errors in radiation delivery can result in harmful overdoses. A substantial need exists for a device that will monitor, in real time, the radiation dose being delivered to a patient. Pacific Northwest Laboratory (PNL) has developed a scintillating glass optical fiber that is sensitive to thermal neutrons. The small size of the fibers offers the possibility of in vivo dose monitoring at several points within the radiation field. The count rate of such detectors can approach 10 MHz because the lifetime of the cerium activator is fast. Fluxes typical of those in BNCT (i.e., 10{sup 9} n/cm{sup 2}/sec) may be measured because of this potentially high count rate and the small diameter of the fiber.

  5. Levels of 186Re populated in thermal neutron capture reaction

    NASA Astrophysics Data System (ADS)

    B?rzinš, J.; Krasta, T.; Simonova, L.; Jentschel, M.; Urban, W.

    2015-05-01

    Levels of 186Re have been studied in the thermal neutron capture reaction with an enriched 185Re target. Evaluation of spectrum measured with GAMS5 allowed to obtain energies and intensities of more than 500 ?-lines assigned to 186Re. Most of the obtained transitions have been placed in the model-independent level scheme of the doubly odd 186Re nucleus, taking into account the available data of earlier experiments as well as the results of recent 187Re(p, d)186Re reaction measurements. Structure of the 186Re low-lying levels has been analysed in terms of the particle-plus-rotor coupling model.

  6. Improved Neutron Capture Gamma-Ray Data and Evaluation

    NASA Astrophysics Data System (ADS)

    Sleaford, B.; Basunia, Shamsuzzoha; Becvar, F.; Belgya, T.; Bernstein, L.; Choi, H.; Escher, J.; Firestone, R.; Genreith, C.; Gunsing, F.; Hurst, A.; Krticka, M.; Revay, Z.; Rossbach, M.; Summers, N.; Szentmiklosi, L.

    2014-09-01

    The neutron-capture reaction is of fundamental use in identifying and analyzing the gamma-ray spectrum from an unknown object as it gives a fingerprint of which isotopes are present. Many isotopes have capture gamma lines from 5-10 MeV potentially making them easier to detect against background lines. There are data gaps in the Evaluated Nuclear Data File (ENDF) libraries used by modeling codes (the actinides have no lines for example) and we are filling these with the Evaluated Gamma-ray Activation File (EGAF), using an IAEA atlas of reactor measured lines and cross sections for over 260 isotopes. For medium to heavy nuclei, the unresolved part of the gamma cascades is not measured and are modeled using the statistical nuclear structure code Dicebox [1,2]. ENDF libraries require cross sections for neutron energies up to 20 MeV and we plan to continue this approach through the resolved resonance region. The neutron-capture reaction is of fundamental use in identifying and analyzing the gamma-ray spectrum from an unknown object as it gives a fingerprint of which isotopes are present. Many isotopes have capture gamma lines from 5-10 MeV potentially making them easier to detect against background lines. There are data gaps in the Evaluated Nuclear Data File (ENDF) libraries used by modeling codes (the actinides have no lines for example) and we are filling these with the Evaluated Gamma-ray Activation File (EGAF), using an IAEA atlas of reactor measured lines and cross sections for over 260 isotopes. For medium to heavy nuclei, the unresolved part of the gamma cascades is not measured and are modeled using the statistical nuclear structure code Dicebox [1,2]. ENDF libraries require cross sections for neutron energies up to 20 MeV and we plan to continue this approach through the resolved resonance region. This work is performed in part under the auspices of the USDoE by LLNL under Contract DE-AC52-07NA27344.

  7. Improved Actinide Neutron Capture Cross Sections Using Accelerator Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Bauder, W.; Pardo, R. C.; Kondev, F. G.; Kondrashev, S.; Nair, C.; Nusair, O.; Palchan, T.; Scott, R.; Seweryniak, D.; Vondrasek, R.; Collon, P.; Paul, M.; Youinou, G.; Salvatores, M.; Palmotti, G.; Berg, J.; Maddock, T.; Imel, G.

    2014-09-01

    The MANTRA (Measurement of Actinide Neutron TRAnsmutations) project will improve energy-integrated neutron capture cross section data across the actinide region. These data are incorporated into nuclear reactor models and are an important piece in understanding Generation IV reactor designs. We will infer the capture cross sections by measuring isotopic ratios from actinide samples, irradiated in the Advanced Test Reactor at INL, with Accelerator Mass Spectrometry (AMS) at ATLAS (ANL). The superior sensitivity of AMS allows us to extract multiple cross sections from a single sample. In order to analyze the large number of samples needed for MANTRA and to meet the goal of extracting multiple cross sections per sample, we have made a number of modifications to the AMS setup at ATLAS. In particular, we are developing a technique to inject solid material into the ECR with laser ablation. With laser ablation, we can better control material injection and potentially increase efficiency in the ECR, thus creating less contamination in the source and reducing cross talk. I will present work on the laser ablation system and preliminary results from our AMS measurements. The MANTRA (Measurement of Actinide Neutron TRAnsmutations) project will improve energy-integrated neutron capture cross section data across the actinide region. These data are incorporated into nuclear reactor models and are an important piece in understanding Generation IV reactor designs. We will infer the capture cross sections by measuring isotopic ratios from actinide samples, irradiated in the Advanced Test Reactor at INL, with Accelerator Mass Spectrometry (AMS) at ATLAS (ANL). The superior sensitivity of AMS allows us to extract multiple cross sections from a single sample. In order to analyze the large number of samples needed for MANTRA and to meet the goal of extracting multiple cross sections per sample, we have made a number of modifications to the AMS setup at ATLAS. In particular, we are developing a technique to inject solid material into the ECR with laser ablation. With laser ablation, we can better control material injection and potentially increase efficiency in the ECR, thus creating less contamination in the source and reducing cross talk. I will present work on the laser ablation system and preliminary results from our AMS measurements. Supported by U.S. DOE, Contract No. DE-AC02-06CH11357.

  8. Computational dosimetry and treatment planning for boron neutron capture therapy.

    PubMed

    Nigg, D W; Wheeler, F J; Wessol, D E; Capala, J; Chadha, M

    1997-05-01

    The technology for computational dosimetry and treatment planning for Boron Neutron Capture Therapy (BNCT) has advanced significantly over the past few years. Because of the more complex nature of the problem, the computational methods that work well for treatment planning in photon radiotherapy are not applicable to BNCT. The necessary methods have, however, been developed and have been successfully employed both for research applications as well as human trials, although further improvements in speed are needed for routine clinical applications. Computational geometry for BNCT applications can be constructed directly from tomographic medical imagery and computed radiation dose distributions can be readily displayed in formats that are familiar to the radiotherapy community. PMID:9151227

  9. Neutron capture records of mesosiderites and an iron meteorite

    NASA Astrophysics Data System (ADS)

    Hidaka, Hiroshi; Yoneda, Shigekazu

    2011-10-01

    The Sm and Gd isotopic compositions of silicates from six mesosiderites (Dalgaranga, Estherville, Morristown, Northwest Africa (NWA) 1242, NWA 2932, and Vaca Muerta) and one iron meteorite (Udei Station) were determined to elucidate the cosmic-ray exposure records. All seven samples showed significant 150Sm/ 149Sm and 158Gd/ 157Gd isotopic shifts from neutron capture reactions corresponding to neutron fluences of (1.3-21.8) × 10 15 n cm -2. In particular, Vaca Muerta showed a significantly higher neutron fluences than the other six samples. The parameter for the degree of neutron thermalization ( ?Sm/ ?Gd) also showed a significant difference between Vaca Muerta (0.76) and the other samples (0.93-1.20). These results suggest a two-stage irradiation of the Vaca Muerta silicates in the parent body (>50 Ma) before formation of the mesosiderite and during its transit to Earth (138 Ma). This is consistent with the 81Kr-Kr cosmic-ray exposure age data of a Vaca Muerta pebble from a previous noble gas isotopic study.

  10. Towards epithermal Boron Neutron Capture Therapy for cancer

    SciTech Connect

    Allen, B.J. [Australian Nuclear Science and Technology Organisation, Menai (Australia)

    1994-12-31

    Progress in the treatment of local disseminating cancer such as high grade brain tumours is poor, and the ability to kill individual cancer cells in the midst of normal cells has not been achieved. Binary therapies hold the most promise of this, and of these Boron Neutron Capture Therapy is the most advanced. Epithermal neutron beams are essential for outpatient treatment of high grade brain tumours and these are now installed and being characterised in Europe and the USA, and are at the design stage in Australia. These beams would allow the bilateral irradiation of the entire brain, and as such are ideally suited for the prophylactic therapy of subclinical metastases. When coupled with appropriate cancer affined boron compounds, therapeutic ratios of 2-3 should be achieved. At present the only source of an epithermal neutron beam is a nuclear reactor. The Euratom reactor at Petten and the Brookhaven Medical Reactor have been retrofitted with filters to produce an epithermal neutron beam. These beams have been characterised and used in dose escalation studies with dogs to study normal tissue tolerance using borocaptate (BSH). Another beam is available at the MIT medical research reactor. Clinical trials at Petten for glioblastoma with BSH and at MIT using boronophenylalanine for melanoma metastases to the extremities are expected to commence this year. The state of the art of reactor based BNCT is reviewed and the potential for a major change in the prognosis of local control of disseminating cancer is explored.

  11. Highlights from 35 Years of Fission Research with Slow Neutrons at the Ill

    NASA Astrophysics Data System (ADS)

    Gönnenwein, F.

    2014-09-01

    The Institut Laue-Langevin in Grenoble/France was founded in 1967 as a center for research with neutrons. The neutron source is a High Flux Reactor. Studies of slow neutron induced fission started in 1975. Since that time some 500 experiments with fission fragments were conducted up to 2012. Out of the many different topics having been tackled only two highlights are selected for the present report: even-odd staggering of proton and neutron numbers of fission fragments in cold fission, and studies of fission with cold polarized neutrons.

  12. Parity violation in polarized neutron capture on parahydrogen and aluminum

    NASA Astrophysics Data System (ADS)

    Tang, Zhaowen

    Parity violation comes from the weak interaction, which is mediated by the W and Z bosons. The hadronic sector of weak interaction is particularly interesting. The natural strength of the interaction is 10-7 times smaller than the strong interaction. This fact, combined with the short range of the weak interaction, allows it to serve as a unique probe of nucleon structure. In this low energy regime QCD is nonperturbative, and quark gluon dynamics is not well understood. Understanding the modification of the weak interaction from the quark level to the nucleon level can shed light on quark-quark correlations in the nucleon. One dynamical theory which attempts to describe the weak hadronic interaction is the DDH model, which uses pi+/-, rho, and o mesons as mediating mesons with small parity violating couplings to nucleons to categorize the interaction. The NPDGamma experiment is sensitive to the hpi1 parameter at the 10-7 level, and is in progress on the Fundamental Neutron Beamline at the Spallation Neutron Source in Oak Ridge National Lab. The NPDGamma experiment measures the parity violating gamma ray asymmetry from polarized neutron capture on parahydrogen. The proposed accuracy will be at 10-8 level, which is a factor of 5 smaller than the theoretical best estimate from DDH. In this thesis, a description of the setup of the experiment is provided, focusing on the parahydrogen target, as well as the analysis techniques, systematic errors and false asymmetries associated with the experiment. The other focus of this thesis will be the analysis of the parity-odd asymmetry from polarized neutron capture on aluminum, which is the biggest source of systematic error for the hydrogen asymmetry.

  13. Boron neutron capture enhancement of 252Cf brachytherapy.

    PubMed

    Beach, J L; Schroy, C B; Ashtari, M; Harris, M R; Maruyama, Y

    1990-06-01

    Dosimetric and radiobiological studies were undertaken to investigate the potential enhancement in dose, dose distribution and cell killing effectiveness of 252Cf brachytherapy achievable when boron-10 enriched compounds are incorporated into simulated 252Cf brain implants. Thermal neutron distributions in a human head phantom containing a 252Cf source were measured by gold foil activation and calculated using a 1-dimensional transport code. This information was then used to modify measured event size distributions for 252Cf neutrons to determine the corresponding increase in dose and dose equivalent throughout the phantom. The addition of subtoxic levels of boron-10 to a typical 252Cf implant was found to significantly enhance both the absorbed dose and the high LET event frequency at distances of 3 to 5 cm from individual sources. Some unexpected geometric considerations are discussed. Reduced survival of cultured Chinese hamster cells correlated with the predicted increase in absorbed dose from the capture events with a concentration of about 60 micrograms 10B per ml in the culture medium. It was found that boron increased alpha (the "single-hit" parameter of the linear quadratic survival model) by 32% and decreased beta (the "double-hit" parameter) by 8%. The alpha/beta ratio increased to 4.34 Gy in the presence of boron, from 3.03 Gy in its absence. This translated to an 8% reduction in californium dose needed to effect 10% cell survival. It is concluded that there is a sufficiently high thermal neutron fluence present during californium brachytherapy for boron neutron capture dose augmentation to be feasible. PMID:2370192

  14. Design of a boron neutron capture enhanced fast neutron therapy assembly

    SciTech Connect

    Wang, Zhonglu

    2006-08-01

    The use of boron neutron capture to boost tumor dose in fast neutron therapy has been investigated at several fast neutron therapy centers worldwide. This treatment is termed boron neutron capture enhanced fast neutron therapy (BNCEFNT). It is a combination of boron neutron capture therapy (BNCT) and fast neutron therapy (FNT). It is believed that BNCEFNT may be useful in the treatment of some radioresistant brain tumors, such as glioblastoma multiform (GBM). A boron neutron capture enhanced fast neutron therapy assembly has been designed for the Fermilab Neutron Therapy Facility (NTF). This assembly uses a tungsten filter and collimator near the patient's head, with a graphite reflector surrounding the head to significantly increase the dose due to boron neutron capture reactions. The assembly was designed using Monte Carlo radiation transport code MCNP version 5 for a standard 20x20 cm{sup 2} treatment beam. The calculated boron dose enhancement at 5.7-cm depth in a water-filled head phantom in the assembly with a 5x5 cm{sup 2} collimation was 21.9% per 100-ppm {sup 10}B for a 5.0-cm tungsten filter and 29.8% for a 8.5-cm tungsten filter. The corresponding dose rate for the 5.0-cm and 8.5-cm thick filters were 0.221 and 0.127 Gy/min, respectively; about 48.5% and 27.9% of the dose rate of the standard 10x10 cm{sup 2} fast neutron treatment beam. To validate the design calculations, a simplified BNCEFNT assembly was built using four lead bricks to form a 5x5 cm{sup 2} collimator. Five 1.0-cm thick 20x20 cm{sup 2} tungsten plates were used to obtain different filter thicknesses and graphite bricks/blocks were used to form a reflector. Measurements of the dose enhancement of the simplified assembly in a water-filled head phantom were performed using a pair of tissue-equivalent ion chambers. One of the ion chambers is loaded with 1000-ppm natural boron (184-ppm {sup 10}B) to measure dose due to boron neutron capture. The measured dose enhancement at 5.0-cm depth in the head phantom for the 5.0-cm thick tungsten filter is (16.6 {+-} 1.8)%, which agrees well with the MCNP simulation of the simplified BNCEFNT assembly, (16.4 {+-} 0.5)%. The error in the calculated dose enhancement only considers the statistical uncertainties. The total dose rate measured at 5.0-cm depth using the non-borated ion chamber is (0.765 {+-} 0.076) Gy/MU, about 61% of the fast neutron standard dose rate (1.255Gy/MU) at 5.0-cm depth for the standard 10x10 cm{sup 2} treatment beam. The increased doses to other organs due to the use of the BNCEFNT assembly were calculated using MCNP5 and a MIRD phantom. The activities of the activation products produced in the BNCEFNT assembly after neutron beam delivery were computed. The photon ambient dose rate due to the radioactive activation products was also estimated.

  15. An irradiation facility for Boron Neutron Capture Therapy application based on a radio frequency driven D-T neutron source and a new beam shaping assembly

    NASA Astrophysics Data System (ADS)

    Cerullo, Nicola; Esposito, Juan; Leung, Ka Ngo; Custodero, Salvatore

    2002-10-01

    A line of the Boron Neutron Capture Therapy (BNCT) research program aimed at the treatment of brain tumors, carried on at the Nuclear Departments of Pisa and Genova Universities (DIMNP and DITEC), is being focused on a new, 3H(d,n)4He (D-T), accelerator-based neutron source concept, developed at Lawrence Berkeley National Laboratory (LBNL). Simple and compact accelerator designs, using mixed D+ T+ ion beam with relatively low energy, ˜100 keV, have been developed which, in turn, can generate high neutron yields. New approaches have thus been started to design an epithermal neutron irradiation facility able to selectively slow the 14.1 MeV D-T neutrons down to the epithermal (1 eV-10 KeV) energy range. New neutron spectrum shifter and filtering materials, as well as different facility layout approaches have been tested. Possible beam shaping assembly models have also been designed. The research demonstrates that a D-T neutron source could be successfully implemented to provide a ˜1×109 n/cm2 s epithermal neutron flux, in spite of its hard spectrum, although a generator device, able to yield ˜1014 n/s is, at present, not yet available. The latest Monte Carlo simulation of an accelerator-based facility, which relies on a single or multiple rf driven DT fusion neutron generator, is presented.

  16. Accelerator-based neutron source for boron neutron capture therapy (BNCT) and method

    DOEpatents

    Yoon, W.Y.; Jones, J.L.; Nigg, D.W.; Harker, Y.D.

    1999-05-11

    A source for boron neutron capture therapy (BNCT) comprises a body of photoneutron emitter that includes heavy water and is closely surrounded in heat-imparting relationship by target material; one or more electron linear accelerators for supplying electron radiation having energy of substantially 2 to 10 MeV and for impinging such radiation on the target material, whereby photoneutrons are produced and heat is absorbed from the target material by the body of photoneutron emitter. The heavy water is circulated through a cooling arrangement to remove heat. A tank, desirably cylindrical or spherical, contains the heavy water, and a desired number of the electron accelerators circumferentially surround the tank and the target material as preferably made up of thin plates of metallic tungsten. Neutrons generated within the tank are passed through a surrounding region containing neutron filtering and moderating materials and through neutron delimiting structure to produce a beam or beams of epithermal neutrons normally having a minimum flux intensity level of 1.0{times}10{sup 9} neutrons per square centimeter per second. Such beam or beams of epithermal neutrons are passed through gamma ray attenuating material to provide the required epithermal neutrons for BNCT use. 3 figs.

  17. Thermal-neutron capture gamma-rays. Volume 2

    SciTech Connect

    Tuli, J.K. [National Nuclear Data Center, Upton, NY (United States)

    1997-05-01

    The energy and photon intensity of gamma rays as seen in thermal-neutron capture are presented ordered by Z, A of target nuclei. All gamma-rays with intensity of {ge}2% of the strongest transition are included. The strongest transition is indicated in each case. Where the target nuclide mass number is indicated as nat the natural target was used. The gamma energies given are in keV. The gamma intensities given are relative to 100 for the strongest transition. All data for A > 44 are taken from Evaluated Nuclear Structure Data File (4/97), a computer file of evaluated nuclear structure data maintained by the National Nuclear Data Center, Brookhaven National Laboratory, on behalf of the Nuclear Structure and Decay and Decay Data network, coordinated by the International Atomic Energy Agency, Vienna. These data are published in Nuclear Data Sheets, Academic Press, San Diego, CA. The data for A {le} 44 is taken from ``Prompt Gamma Rays from Thermal-Neutron Capture,`` M.A. Lone, R.A. Leavitt, D.A. Harrison, Atomic Data and Nuclear Data Tables 26, 511 (1981).

  18. Optimal Neutron Source and Beam Shaping Assembly for Boron Neutron Capture Therapy

    E-print Network

    Vujic, J L; Greenspan, E; Guess, S; Karni, Y; Kastenber, W E; Kim, L; Leung, K N; Regev, D; Verbeke, J M; Waldron, W L; Zhu, Y

    2003-01-01

    There were three objectives to this project: (1) The development of the 2-D Swan code for the optimization of the nuclear design of facilities for medical applications of radiation, radiation shields, blankets of accelerator-driven systems, fusion facilities, etc. (2) Identification of the maximum beam quality that can be obtained for Boron Neutron Capture Therapy (BNCT) from different reactor-, and accelerator-based neutron sources. The optimal beam-shaping assembly (BSA) design for each neutron source was also to e obtained. (3) Feasibility assessment of a new neutron source for NCT and other medical and industrial applications. This source consists of a state-of-the-art proton or deuteron accelerator driving and inherently safe, proliferation resistant, small subcritical fission assembly.

  19. A Sealed-Accelerator-Tube Neutron Generator for Boron Neutron Capture Therapy Application

    SciTech Connect

    Leung, K.-N.; Leung, K.N.; Lee, Y.; Verbeke, J.M.; Vurjic, J.; Williams, M.D.; Wu, L.K.; Zahir, N.

    1998-06-01

    Radio-frequency (RF) driven ion sources are being developed in Lawrence Berkeley National Laboratory (LBNL) for sealed-accelerator-tube neutron generator applications. By using a 2.5-cm-diameter RF-driven multicusp source and a computer designed 100 keV accelerator column, peak extractable hydrogen current exceeding 1 A from a 3-mm-diameter aperture, together with H{sup +} yields over 94% have been achieved. These experimental findings together with recent moderator design will enable one to develop compact 14 MeV neutron generators based on the D-T fusion reaction. In this new neutron generator, the ion source, the accelerator and the target are all housed in a sealed metal container without pumping. With a 120 keV and 1 A deuteron beam, it is estimated that a treatment time of {approx} 45 minutes is needed for boron neutron capture therapy.

  20. Optimal Neutron Source & Beam Shaping Assembly for Boron Neutron Capture Therapy

    SciTech Connect

    J. Vujic; E. Greenspan; W.E. Kastenber; Y. Karni; D. Regev; J.M. Verbeke, K.N. Leung; D. Chivers; S. Guess; L. Kim; W. Waldron; Y. Zhu

    2003-04-30

    There were three objectives to this project: (1) The development of the 2-D Swan code for the optimization of the nuclear design of facilities for medical applications of radiation, radiation shields, blankets of accelerator-driven systems, fusion facilities, etc. (2) Identification of the maximum beam quality that can be obtained for Boron Neutron Capture Therapy (BNCT) from different reactor-, and accelerator-based neutron sources. The optimal beam-shaping assembly (BSA) design for each neutron source was also to e obtained. (3) Feasibility assessment of a new neutron source for NCT and other medical and industrial applications. This source consists of a state-of-the-art proton or deuteron accelerator driving and inherently safe, proliferation resistant, small subcritical fission assembly.

  1. Improved monitoring system of neutron flux during boron-neutron capture therapy

    SciTech Connect

    Harasawa, S. (Rikkyo Univ., Nagasaka, Japan); Nakamoto, A.; Hayakawa, Y.; Egawa, J.

    1981-10-01

    Continuous and simultaneous monitoring of neutron flux in the course of a boron-neutron capture operation on a brain tumor has been achieved using a new monitoring system. A silicon surface barrier diode mounted with /sup 6/LiF instead of the previously reported borax is used to sense neutrons. The pulse heights of /sup 3/H and ..cap alpha.. particles from /sup 6/Li(n, ..cap alpha..)/sup 2/H reaction are sufficiently high and well separated from noises due to ..gamma.. rays. The effect of pulse-height reduction due to the radiation damage of the diode thus becomes smaller, permitting continuous monitoring. The relative error of the monitoring is within 2% over 5 hr for a neutron-flux density of 2 x 10/sup 9/ n/cm/sup 2/ sec.

  2. Measurement of augmentation of 252Cf implant by 10B and 157Gd neutron capture.

    PubMed

    Wierzbicki, J G; Maruyama, Y; Porter, A T

    1994-06-01

    252Cf has been used as a brachytherapy source since the early 1970s. The dominant mechanism of interactions of 252Cf neutrons with tissue is elastic scattering. The scattered neutrons lose part of their energy, which is released as kinetic energy of the recoiling nuclei. By multiple scattering, neutrons lose their energy and eventually become thermalized (in energetic equilibrium with tissue atoms with an average energy of 0.025 eV) and do not play any role in radiotherapy. These thermal neutrons may interact with hydrogen nuclei or with nitrogen, but the cell killing effects by these reaction products are negligibly small compared to the elastic scattering by fast neutrons or by photons emitted by californium. Nonetheless, these thermal neutrons are still potentially usable for neutron capture therapy and can be used to enhance californium brachytherapy effects. Neutron capture therapy is a two-part therapy relying on the selective loading of tumor cells with compounds containing 10B or 157Gd and subsequent irradiation with thermal neutrons. To calculate neutron capture doses one has to know thermal neutron flux. This paper presents results of an experimental study of thermal neutron flux and calculations of boron neutron capture and gadolinium neutron capture doses in the vicinity of 252Cf sources. PMID:7935215

  3. FUSE Observations of Neutron-Capture Elements in Wolf-Rayet Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    Dinerstein, H.

    We propose to obtain FUSE observations of planetary nebula central stars of the WC Wolf-Rayet ([WC]) class, in order to search for the products of neutron-capture processes in these stars and provide constraints on their evolutionary status. Although the origin of the [WC]'s is controversial, their H-deficient, C-rich surface compositions indicate that they have experienced a high degree of mixing and/or mass loss. Thus one might expect the nebulae they produce to show enhanced concentrations of He-burning and other nuclear products, such as nuclei produced by slow neutron capture during the AGB phase. We have already detected an absorption line from one such element, Germanium (Sterling, Dinerstein, & Bowers 2002), while conducting a search for H2 absorption from nebular molecular material FUSE GI programs A085 and B069). Since the strongest Ge enhancements were found in PNe with [WC] central stars, we propose to enlarge the sample of such objects observed by FUSE. THIS TEMPORARY AND PARTIAL SCRIPT COVERS ONE TARGET, HE 2-99, AND REQUESTS AN EXPOSURE TIME OF 15 KSEC. PHASE 2 INFORMATION FOR THE REMAINDER OF THE PROGRAM'S TOTAL TIME ALLOCATION OF 60 KSEC WILL BE SUBMITTED AT A LATER TIME.

  4. Treatment Planning for Accelerator-Based Boron Neutron Capture Therapy

    SciTech Connect

    Herrera, Maria S.; Gonzalez, Sara J. [Comision National de Energia Atomica and CONICET, Buenos Aires (Argentina); Minsky, Daniel M.; Kreiner, Andres J. [Comision National de Energia Atomica and CONICET, Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, UNSAM, Buenos Aires (Argentina)

    2010-08-04

    Glioblastoma multiforme and metastatic melanoma are frequent brain tumors in adults and presently still incurable diseases. Boron Neutron Capture Therapy (BNCT) is a promising alternative for this kind of pathologies. Accelerators have been proposed for BNCT as a way to circumvent the problem of siting reactors in hospitals and for their relative simplicity and lower cost among other advantages. Considerable effort is going into the development of accelerator-based BNCT neutron sources in Argentina. Epithermal neutron beams will be produced through appropriate proton-induced nuclear reactions and optimized beam shaping assemblies. Using these sources, computational dose distributions were evaluated in a real patient with diagnosed glioblastoma treated with BNCT. The simulated irradiation was delivered in order to optimize dose to the tumors within the normal tissue constraints. Using Monte Carlo radiation transport calculations, dose distributions were generated for brain, skin and tumor. Also, the dosimetry was studied by computing cumulative dose-volume histograms for volumes of interest. The results suggest acceptable skin average dose and a significant dose delivered to tumor with low average whole brain dose for irradiation times less than 60 minutes, indicating a good performance of an accelerator-based BNCT treatment.

  5. Computational dosimetry and treatment planning considerations for neutron capture therapy.

    PubMed

    Nigg, David W

    2003-01-01

    Specialized treatment planning software systems are generally required for neutron capture therapy (NCT) research and clinical applications. The standard simplifying approximations that work well for treatment planning computations in the case of many other modalities are usually not appropriate for application to neutron transport. One generally must obtain an explicit three-dimensional numerical solution of the governing transport equation, with energy-dependent neutron scattering completely taken into account. Treatment planning systems that have been successfully introduced for NCT applications over the past 15 years rely on the Monte Carlo stochastic simulation method for the necessary computations, primarily because of the geometric complexity of human anatomy. However, historically, there has also been interest in the application of deterministic methods, and there have been some practical developments in this area. Most recently, interest has turned toward the creation of treatment planning software that is not limited to any specific therapy modality, with NCT as only one of several applications. A key issue with NCT treatment planning has to do with boron quantification, and whether improved information concerning the spatial biodistribution of boron can be effectively used to improve the treatment planning process. Validation and benchmarking of computations for NCT are also of current developmental interest. Various institutions have their own procedures, but standard validation models are not yet in wide use. PMID:12749704

  6. A critical assessment of boron neutron capture therapy: an overview.

    PubMed

    Barth, Rolf F

    2003-01-01

    Boron neutron capture therapy (BNCT) is based on the nuclear reaction that occurs when boron-10 is irradiated with neutrons of the appropriate energy to produce high-energy alpha particles and recoiling lithium-7 nuclei. BNCT has been used clinically to treat patients with high-grade gliomas, and a much smaller number with primary and metastatic melanoma. The purpose of this special issue of the Journal of Neuro-Oncology is to provide a critical and realistic assessment of various aspects of basic and clinical BNCT research in order to better understand its present status and future potential. Topics that are covered include neutron sources, tumor-targeted boron delivery agents, brain tumor models to assess therapeutic efficacy, computational dosimetry and treatment planning, results of clinical trails in the United States, Japan and Europe, pharmacokinetic studies of sodium borocaptate and boronophenylalanine (BPA), positron emission tomography imaging of BPA for treatment planning, and finally an overview of the challenges and problems that must be faced if BNCT is to become a useful treatment modality for brain tumors. Clinical studies have demonstrated the safety of BNCT. The next challenge is an unequivocal demonstration of therapeutic efficacy in one or more of the clinical trails that either are in progress or are planned over the next few years. PMID:12749698

  7. Thermal neutron capture cross sections and neutron separation energies for 23Na(n,?)

    NASA Astrophysics Data System (ADS)

    Firestone, R. B.; Revay, Zs.; Belgya, T.

    2014-01-01

    Prompt thermal neutron capture ?-ray cross sections ?? were measured for the 23Na(n,?) reaction with guided cold neutron beams at the Budapest Reactor. The 24Na ?-ray cross sections were internally standardized with a stoichiometric NaCl target by using standard 35Cl(n,?)36Cl ?-ray cross sections. Transitions were assigned to levels in 24Na based primarily upon the known nuclear structure information from the literature, producing a nearly complete neutron capture decay scheme. The total radiative thermal neutron cross section ?0 was determined from the sum of prompt ?-ray cross section populating the ground state as 0.540 (3) b, and from the activation ?-ray cross sections for the decay of 24Na as 0.542 (3) b. The isomer cross section ?0 (23Nam, t1/2=20.20ms)=0.501(3) b and the 24Na neutron separation energy Sn=6959.352(18) keV were also determined in these experiments. New level spins and parities were proposed on the basis of new transition assignments and the systematics of reduced transition probabilities for the primary ? rays.

  8. Neutron Tube Design Study for Boron Neutron Capture TherapyApplication

    SciTech Connect

    Verbeke, J.M.; Lee, Y.; Leung, K.N.; Vujic, J.; Williams, M.D.; Wu, L.K.; Zahir, N.

    1998-01-04

    Radio-frequency (RF) driven ion sources are being developed in Lawrence Berkeley National Laboratory (LBNL) for sealed-accelerator-tube neutron generator application. By using a 5-cm-diameter RF-driven multicusp source H{sup +} yields over 95% have been achieved. These experimental findings will enable one to develop compact neutron generators based on the D-D or D-T fusion reactions. In this new neutron generator, the ion source, the accelerator and the target are all housed in a sealed metal container without external pumping. Recent moderator design simulation studies have shown that 14 MeV neutrons could be moderated to therapeutically useful energy ranges for boron neutron capture therapy (BNCT). The dose near the center of the brain with optimized moderators is about 65% higher than the dose obtained from a typical neutron spectrum produced by the Brookhaven Medical Research Reactor (BMRR), and is comparable to the dose obtained by other accelerator-based neutron sources. With a 120 keV and 1 A deuteron beam, a treatment time of {approx}35 minutes is estimated for BNCT.

  9. NIFTI and DISCOS: New concepts for a compact accelerator neutron source for boron neutron capture therapy applications

    Microsoft Academic Search

    J. Powell; H. Ludewig; M. Todosow; M. Reich

    1995-01-01

    Two new concepts, NIFTI and DISCOS, are described. These concepts enable the efficient production of epithermal neutrons for BNCT (Boron Neutron Capture Therapy) medical treatment, utilizing a low current, low energy proton beam impacting on a lithium target. The NIFTI concept uses fluoride compounds, such as lead or beryllium fluoride, to efficiently degrade high energy neutrons from the lithium target

  10. Optimal Neutron Source & Beam Shaping Assembly for Boron Neutron Capture Therapy

    Microsoft Academic Search

    J. Vujic; E. Greenspan; W. E. Kastenber; Y. Karni; D. Regev; K. N. Leung J. M. Verbeke; D. Chivers; S. Guess; L. Kim; W. Waldron; Y. Zhu

    2003-01-01

    There were three objectives to this project: (1) The development of the 2-D Swan code for the optimization of the nuclear design of facilities for medical applications of radiation, radiation shields, blankets of accelerator-driven systems, fusion facilities, etc. (2) Identification of the maximum beam quality that can be obtained for Boron Neutron Capture Therapy (BNCT) from different reactor-, and accelerator-based

  11. Neutron Capture Cross Section Calculations with the Statistical Model

    NASA Astrophysics Data System (ADS)

    Beard, Mary; Uberseder, Ethan; Wiescher, Michael

    2014-09-01

    Hauser-Feshbach (HF) cross sections are of enormous importance for a wide range of applications, from waste transmutation and nuclear technologies, to medical applications, and nuclear astrophysics. It is a well observed result that different nuclear input models sensitively affect HF cross section calculations. Less well-known however are the effects on calculations originating from model-specific implementation details (such as level density parameter, matching energy, backshift and giant dipole parameters), as well as effects from non-model aspects, such as experimental data truncation and transmission function energy binning. To investigate the effects or these various aspects, Maxwellian-averaged neutron capture cross sections have been calculated for approximately 340 nuclei. The relative effects of these model details will be discussed.

  12. Neutron Single Particle Structure in Sn131 and Direct Neutron Capture Cross Sections

    NASA Astrophysics Data System (ADS)

    Kozub, R. L.; Arbanas, G.; Adekola, A. S.; Bardayan, D. W.; Blackmon, J. C.; Chae, K. Y.; Chipps, K. A.; Cizewski, J. A.; Erikson, L.; Hatarik, R.; Hix, W. R.; Jones, K. L.; Krolas, W.; Liang, J. F.; Ma, Z.; Matei, C.; Moazen, B. H.; Nesaraja, C. D.; Pain, S. D.; Shapira, D.; Shriner, J. F., Jr.; Smith, M. S.; Swan, T. P.

    2012-10-01

    Recent calculations suggest that the rate of neutron capture by Sn130 has a significant impact on late-time nucleosynthesis in the r process. Direct capture into low-lying bound states is expected to be significant in neutron capture near the N=82 closed shell, so r-process reaction rates may be strongly impacted by the properties of neutron single particle states in this region. In order to investigate these properties, the (d,p) reaction has been studied in inverse kinematics using a 630 MeV beam of Sn130 (4.8MeV/u) and a (CD2)n target. An array of Si strip detectors, including the Silicon Detector Array and an early implementation of the Oak Ridge Rutgers University Barrel Array, was used to detect reaction products. Results for the Sn130(d,?p)Sn131 reaction are found to be very similar to those from the previously reported Sn132(d,?p)Sn133 reaction. Direct-semidirect (n,?) cross section calculations, based for the first time on experimental data, are presented. The uncertainties in these cross sections are thus reduced by orders of magnitude from previous estimates.

  13. Neutron single particle structure in 131Sn and direct neutron capture cross sections

    SciTech Connect

    Kozub, R. L. [Tennessee Technological University; Arbanas, Goran [ORNL; Adekola, A. S. [Ohio University, Athens; Bardayan, Daniel W [ORNL; Blackmon, Jeffery C [Louisiana State University; Chae, Kyung Yuk [ORNL; Chipps, K. [Colorado School of Mines, Golden; Cizewski, J. A. [Rutgers University; Erikson, Luke [Colorado School of Mines, Golden; Hatarik, Robert [Rutgers University; Hix, William Raphael [ORNL; Jones, K. L. [University of Tennessee, Knoxville (UTK); Krolas, W. [University of Warsaw; Liang, J Felix [ORNL; Ma, Z. [University of Tennessee, Knoxville (UTK); Matei, Catalin [Oak Ridge Associated Universities (ORAU); Moazen, Brian [University of Tennessee, Knoxville (UTK); Nesaraja, Caroline D [ORNL; Pain, Steven D [ORNL; Shapira, Dan [ORNL; ShrinerJr., J. F. [Tennessee Technological University; Smith, Michael Scott [ORNL; Swan, T. P. [University of Surrey, UK

    2012-01-01

    Recent calculations suggest that the rate of neutron capture by 130Sn has a significant impact on late-time nucleosynthesis in the r-process. Direct capture into low-lying bound states is expected to be significant in neutron capture near the N=82 closed shell, so r- process reaction rates may be strongly impacted by the properties of neutron single particle states in this region. In order to investigate these properties, the (d, p) reaction has been studied in inverse kinematics using a 630 MeV beam of 130Sn (4.8 MeV/u) and a (CD2)n target. An array of Si strip detectors, including SIDAR and an early implementation of the ORRUBA, was used to detect reaction products. Results for the 130Sn(d, p)131Sn reaction are found to be very similar to those from the previously reported 132Sn(d, p)133Sn reaction. Direct-semidirect (n, ) cross section calculations, based for the first time on experimental data, are presented. The uncertainties in these cross sections are thus reduced by orders of magnitude from previous estimates.

  14. Gadolinium as an element for neutron capture therapy

    SciTech Connect

    Brugger, R.M.; Liu, H.B.; Laster, B.H.; Gordon, C.R.; Greenberg, D.D.; Warkentien, L.S.

    1992-01-01

    At BNL, preparations are being made to test in vitro compounds containing Gd and compare their response to the response of GD-DTPA to determine if one or several compounds can be located that enter the cells and enhance the Auger effect. Two similar rotators with positions for cell vials that have been constructed for these tests. The first rotator is made of only paraffin which simulates healthy tissue and provides control curves. The second rotator has 135 ppM of Gd-157 in the paraffin to simulate a Gd loaded tumor. Cells are irradiated in vials in the paraffin rotator and in the Gd-paraffin rotator at the epithermal beam of the Brookhaven Medical Research Reactor (BMRR). This produces an irradiation similar to what a patient would receive In an actual treatment. A combination of irradiations are made with both rotators; with no Gd compound or IdUrd In the cell media, with only Gd compound in the cell media and with both Gd compound and IdUrd in the cell media. The first set shows the effects of gamma rays from the H(n,gamma) reaction and the prompt gamma rays from capture of neutrons by Gd. The second set shows if there is any effect of Gd being in the cell media or inside the cells, i.e., an Auger effect. The third set shows the effect of enhancement by the IdUrd produced by the gamma rays from neutrons captured by either H or Gd. The fourth set combines all of the reactions and enhancements. Preliminary calculations and physical measurements of the doses that the cells will receive In these rotators have been made.

  15. Gadolinium as an element for neutron capture therapy

    SciTech Connect

    Brugger, R.M.; Liu, H.B.; Laster, B.H.; Gordon, C.R.; Greenberg, D.D.; Warkentien, L.S.

    1992-12-31

    At BNL, preparations are being made to test in vitro compounds containing Gd and compare their response to the response of GD-DTPA to determine if one or several compounds can be located that enter the cells and enhance the Auger effect. Two similar rotators with positions for cell vials that have been constructed for these tests. The first rotator is made of only paraffin which simulates healthy tissue and provides control curves. The second rotator has 135 ppM of Gd-157 in the paraffin to simulate a Gd loaded tumor. Cells are irradiated in vials in the paraffin rotator and in the Gd-paraffin rotator at the epithermal beam of the Brookhaven Medical Research Reactor (BMRR). This produces an irradiation similar to what a patient would receive In an actual treatment. A combination of irradiations are made with both rotators; with no Gd compound or IdUrd In the cell media, with only Gd compound in the cell media and with both Gd compound and IdUrd in the cell media. The first set shows the effects of gamma rays from the H(n,gamma) reaction and the prompt gamma rays from capture of neutrons by Gd. The second set shows if there is any effect of Gd being in the cell media or inside the cells, i.e., an Auger effect. The third set shows the effect of enhancement by the IdUrd produced by the gamma rays from neutrons captured by either H or Gd. The fourth set combines all of the reactions and enhancements. Preliminary calculations and physical measurements of the doses that the cells will receive In these rotators have been made.

  16. Epithermal neutron formation for boron neutron capture therapy by adiabatic resonance crossing concept

    NASA Astrophysics Data System (ADS)

    Khorshidi, A.; Ghafoori-Fard, H.; Sadeghi, M.

    2014-05-01

    Low-energy protons from the cyclotron in the range of 15-30 MeV and low current have been simulated on beryllium (Be) target with a lead moderator around the target. This research was accomplished to design an epithermal neutron beam for Boron Neutron Capture Therapy (BNCT) using the moderated neutron on the average produced from 9Be target via (p, xn) reaction in Adiabatic Resonance Crossing (ARC) concept. Generation of neutron to proton ratio, energy distribution, flux and dose components in head phantom have been simulated by MCNP5 code. The reflector and collimator were designed in prevention and collimation of derivation neutrons from proton bombarding. The scalp-skull-brain phantom consisting of bone and brain equivalent material has been simulated in order to evaluate the dosimetric effect on the brain. Results of this analysis demonstrated while the proton energy decreased, the dose factor altered according to filters thickness. The maximum epithermal flux revealed using fluental, Fe and bismuth (Bi) filters with thicknesses of 9.4, 3 and 2 cm, respectively and also the epithermal to thermal neutron flux ratio was 103.85. The potential of the ARC method to replace or complement the current reactor-based supply sources of BNCT purposes.

  17. Boron analysis and boron imaging in biological materials for Boron Neutron Capture Therapy (BNCT)

    Microsoft Academic Search

    Andrea Wittig; Jean Michel; Raymond L. Moss; Finn Stecher-Rasmussen; Heinrich F. Arlinghaus; Peter Bendel; Pier Luigi Mauri; Saverio Altieri; Ralf Hilger; Piero A. Salvadori; Luca Menichetti; Robert Zamenhof; Wolfgang A. G. Sauerwein

    2008-01-01

    Boron Neutron Capture Therapy (BNCT) is based on the ability of the stable isotope 10B to capture neutrons, which leads to a nuclear reaction producing an alpha- and a 7Li-particle, both having a high biological effectiveness and a very short range in tissue, being limited to approximately one cell diameter. This opens the possibility for a highly selective cancer therapy.

  18. Tidal capture of primordial black holes by neutron stars

    NASA Astrophysics Data System (ADS)

    Defillon, Guillaume; Granet, Etienne; Tinyakov, Peter; Tytgat, Michel H. G.

    2014-11-01

    The fraction of primordial black holes (PBHs) of masses 1017- 1026 g in the total amount of dark matter may be constrained by considering their capture by neutron stars (NSs), which leads to the rapid destruction of the latter. The constraints depend crucially on the capture rate which, in turn, is determined by the energy loss by a PBH passing through a NS. Two alternative approaches to estimate the energy loss have been used in the literature: the one based on the dynamical friction mechanism, and another on tidal deformations of the NS by the PBH. The second mechanism was claimed to be more efficient by several orders of magnitude due to the excitation of particular oscillation modes reminiscent of the surface waves. We address this disagreement by considering a simple analytically solvable model that consists of a flat incompressible fluid in an external gravitational field. In this model, we calculate the energy loss by a PBH traversing the fluid surface. We find that the excitation of modes with the propagation velocity smaller than that of PBH is suppressed, which implies that in a realistic situation of a supersonic PBH the large contributions from the surface waves are absent and the above two approaches lead to consistent expressions for the energy loss.

  19. Boron neutron capture therapy in cancer: past, present and future.

    PubMed

    Pisarev, Mario A; Dagrosa, Maria Alejandra; Juvenal, Guilermo J

    2007-07-01

    Undifferentiated thyroid cancer (UTC) is a very aggressive tumor with no effective treatment, since it lacks iodine uptake and does not respond to radio or chemotherapy. The prognosis of these patients is bad, due to the rapid growth of the tumor and the early development of metastasis. Boron neutron capture therapy (BNCT) is based on the selective uptake of certain boron non-radioactive compounds by a tumor, and the subsequent irradiation of the area with an appropriate neutron beam. 10B is then activated to 11B, which will immediately decay releasing alpha particles and 7Li, of high linear energy transfer (LET) and limited reach. Clinical trials are being performed in patients with glioblastoma multiforme and melanoma. We have explored its possible application to UTC. Our results demonstrated that a cell line of human UTC has a selective uptake of borophenylalanine (BPA) both in vitro and after transplantation to nude mice. Treatment of mice by BNCT led to a complete control of growth and cure of 100% of the animals. Moreover dogs with spontaneous UTC also have a selective uptake of BPA. At the present we are studying the biodistribution of BPA in patients with UTC before its application in humans. PMID:17891250

  20. Landmine detection method combined with backscattering neutrons and capture ?-rays from hydrogen.

    PubMed

    Takahashi, Yoshiyuki; Misawa, Tsuyoshi; Pyeon, Cheol Ho; Shiroya, Seiji; Yoshikawa, Kiyoshi

    2011-07-01

    The usefulness of the measurements of the backscattering neutron and 2.22MeV capture ?-ray from hydrogen in the landmine detection method is described in this paper. When the soil moisture content is increased, the reaction rates of both the neutron scattering reaction and capture reaction are increased. However, the backscattering neutrons are more influenced than the capture ?-rays by the soil moisture before the reaction with the detector. The facts that the backscattering neutron method is useful in the dry soil case and that the capture ?-ray method is effective in well-wet soil case are confirmed by the experiments and the calculations. The landmine detection efficiency is improved in various soil moisture conditions by combining the backscattering neutron method together with the capture ?-ray method. The effectiveness of the pulse mode operation was confirmed numerically. PMID:21481597

  1. Investigation of the tungsten isotopes via thermal neutron capture

    NASA Astrophysics Data System (ADS)

    Hurst, A. M.; Firestone, R. B.; Sleaford, B. W.; Summers, N. C.; Révay, Zs.; Szentmiklósi, L.; Basunia, M. S.; Belgya, T.; Escher, J. E.; Krti?ka, M.

    2014-01-01

    Total radiative thermal neutron-capture ?-ray cross sections for the 182,183,184,186W isotopes were measured using guided neutron beams from the Budapest Research Reactor to induce prompt and delayed ? rays from natural and isotopically-enriched tungsten targets. These cross sections were determined from the sum of measured ?-ray cross sections feeding the ground state from low-lying levels below a cutoff energy, Ecrit, where the level scheme is completely known, and continuum ? rays from levels above Ecrit, calculated using the Monte Carlo statistical-decay code dicebox. The new cross sections determined in this work for the tungsten nuclides are ?0(182W)=20.5(14) b and ?11/2+(183Wm,5.2s )=0.177(18) b; ?0(183W)=9.37(38) b and ?5-(184Wm,8.33?s )=0.0247(55) b; ?0(184W)=1.43(10) b and ?11/2+(185Wm,1.67min)=0.0062(16) b; and, ?0(186W)=33.33(62) b and ?9/2+(187Wm,1.38?s)=0.400(16) b. These results are consistent with earlier measurements in the literature. The 186W cross section was also independently confirmed from an activation measurement, following the decay of 187W, yielding values for ?0(186W) that are consistent with our prompt ?-ray measurement. The cross-section measurements were found to be insensitive to choice of level density or photon strength model and only weakly dependent on Ecrit. Total radiative-capture widths calculated with dicebox showed much greater model dependence; however, the recommended values could be reproduced with selected model choices. The decay schemes for all tungsten isotopes were improved in these analyses. We were also able to determine new neutron-separation energies from our primary ?-ray measurements for the respective (n ,?) compounds: 183W [Sn=6190.88(6) keV]; 184W [Sn=7411.11(13) keV]; 185W [Sn=5753.74(5) keV]; and, 187W [Sn=5466.62(7) keV].

  2. Neutron-capture elements in the s- and r-process-rich stars: Constraints on neutron-capture nucleosynthesis processes

    E-print Network

    Bo Zhang; Kun Ma; Guide Zhou

    2006-05-14

    The chemical abundances of the very metal-poor double-enhanced stars are excellent information for setting new constraints on models of neutron-capture processes at low metallicity. These stars are known as s+r stars, since they show enhancements of both s-process and r-process elements. The observed abundance ratios for the double-enhanced stars can be explained by those of stars that were polluted by an AGB star and subsequently accreted very significant amounts of r-process material out of an AIC (accretion-induced collapse) or Type 1.5 supernova. In this paper we present for the first time an attempt to fit the elemental abundances observed in the s- and r-rich, very metal-poor stars using a parametric model and suggest a new concept of component coefficients to describe the contributions of the individual neutron-capture processes to double-enhanced stars. We find that the abundance ratios of these stars are best fitted by enrichments of s- and r-process material. The overlap factor in the AGB stars where the observed s-process elements were produced lies between 0.1 and 0.81. Taking into account the dependence of the initial-final mass relations on metallicity, this wide range of values could possibly be explained by a wide range of core-mass values of AGB stars at low metallicity. The component coefficient of the r-process is strongly correlated with the component coefficient of the s-process for the double-enhanced stars. This is significant evidence that the r-process material in double-enhanced stars comes from an AIC or Type 1.5 supernova.

  3. Neutron capture cross-sections of stable xenon isotopes and their application in stellar nucleosynthesis

    Microsoft Academic Search

    H. Beer; F. Kaeppeler; G. Reffo; G. Venturini

    1983-01-01

    The neutron capture cross-sections of124, 132, 134Xe have been measured by the activation technique at 25 keV neutron energy. These data were supplemented by calculated capture cross-sections for128, 129, 130, 131Xe via the statistical model. The complete set of capture cross-sections obtained in this way served to determine the solar xenon abundance throughs-process systematics and to study a variety of

  4. Application of an ultraminiature thermal neutron monitor for irradiation field study of accelerator-based neutron capture therapy

    PubMed Central

    Ishikawa, Masayori; Tanaka, Kenichi; Endo, Satrou; Hoshi, Masaharu

    2015-01-01

    Phantom experiments to evaluate thermal neutron flux distribution were performed using the Scintillator with Optical Fiber (SOF) detector, which was developed as a thermal neutron monitor during boron neutron capture therapy (BNCT) irradiation. Compared with the gold wire activation method and Monte Carlo N-particle (MCNP) calculations, it was confirmed that the SOF detector is capable of measuring thermal neutron flux as low as 105 n/cm2/s with sufficient accuracy. The SOF detector will be useful for phantom experiments with BNCT neutron fields from low-current accelerator-based neutron sources. PMID:25589504

  5. Application of an ultraminiature thermal neutron monitor for irradiation field study of accelerator-based neutron capture therapy.

    PubMed

    Ishikawa, Masayori; Tanaka, Kenichi; Endo, Satrou; Hoshi, Masaharu

    2015-03-01

    Phantom experiments to evaluate thermal neutron flux distribution were performed using the Scintillator with Optical Fiber (SOF) detector, which was developed as a thermal neutron monitor during boron neutron capture therapy (BNCT) irradiation. Compared with the gold wire activation method and Monte Carlo N-particle (MCNP) calculations, it was confirmed that the SOF detector is capable of measuring thermal neutron flux as low as 10(5) n/cm(2)/s with sufficient accuracy. The SOF detector will be useful for phantom experiments with BNCT neutron fields from low-current accelerator-based neutron sources. PMID:25589504

  6. Boron neutron capture therapy (BNCT): implications of neutron beam and boron compound characteristics.

    PubMed

    Wheeler, F J; Nigg, D W; Capala, J; Watkins, P R; Vroegindeweij, C; Auterinen, I; Seppälä, T; Bleuel, D

    1999-07-01

    The potential efficacy of boron neutron capture therapy (BNCT) for malignant glioma is a significant function of epithermal-neutron beam biophysical characteristics as well as boron compound biodistribution characteristics. Monte Carlo analyses were performed to evaluate the relative significance of these factors on theoretical tumor control using a standard model. The existing, well-characterized epithermal-neutron sources at the Brookhaven Medical Research Reactor (BMRR), the Petten High Flux Reactor (HFR), and the Finnish Research Reactor (FiR-1) were compared. Results for a realistic accelerator design by the E. O. Lawrence Berkeley National Laboratory (LBL) are also compared. Also the characteristics of the compound p-Boronophenylaline Fructose (BPA-F) and a hypothetical next-generation compound were used in a comparison of the BMRR and a hypothetical improved reactor. All components of dose induced by an external epithermal-neutron beam fall off quite rapidly with depth in tissue. Delivery of dose to greater depths is limited by the healthy-tissue tolerance and a reduction in the hydrogen-recoil and incident gamma dose allow for longer irradiation and greater dose at a depth. Dose at depth can also be increased with a beam that has higher neutron energy (without too high a recoil dose) and a more forward peaked angular distribution. Of the existing facilities, the FiR-1 beam has the better quality (lower hydrogen-recoil and incident gamma dose) and a penetrating neutron spectrum and was found to deliver a higher value of Tumor Control Probability (TCP) than other existing beams at shallow depth. The greater forwardness and penetration of the HFR the FiR-1 at greater depths. The hypothetical reactor and accelerator beams outperform at both shallow and greater depths. In all cases, the hypothetical compound provides a significant improvement in efficacy but it is shown that the full benefit of improved compound is not realized until the neutron beam is fully optimized. PMID:10435523

  7. Optical Spectroscopy of Slow, Highly Charged Ions after Collision with - Study of Electron Capture.

    NASA Astrophysics Data System (ADS)

    Gauntt, David Michael

    1990-01-01

    We have studied electron capture using a recoil ion source to produce beams of neon and argon ions, directed into a beam of atomic sodium. We have measured the wavelengths, relative intensities, and polarizations of the subsequent visible radiation due to DeltaN = -1 transitions. We have determined the partial capture cross sections of these systems as a function of velocity. In all systems studied, the partial cross sections at low velocity are largest for S levels, and at higher velocity are largest for the highest L levels; all cross sections are several orders of magnitude larger than Multichannel Landau-Zener model predictions. We have also determined the J distributions in the 9P and 9F manifolds of Ar^{ rm 7+*}, and have shown them to be statistical. Close coupling theory predicts that for slow collisions the electron is captured almost exclusively into the m _{rm L} = 0 state of the final system, yielding the highest possible polarization. As the velocity of the projectile increases, rotational coupling mixes in other m_{rm L} states, reducing the polarization. We have measured the polarization of the brightest lines in the spectra of the Ne^{rm 8+}, Ne^{rm 7+}, Ar ^{rm 9+} and Ar^ {rm 8+} + Na systems as a function of velocity. Lines corresponding to transitions from low L levels have no measurable polarization. For Ne ^{rm 8+} projectiles the polarization of light from high L levels shows no measurable change over the velocities used, for Ne^ {rm 7+} and Ar^{ rm 9+} it either remains constant or increases, and for Ar^{rm 8+ } it increases. We propose a theoretical explanation of this behavior. We have measured the wavelengths of strong transitions in the n = 9-8 manifold in the systems Ne^{rm 7+*} and Ar^{rm 7+*}. The wavelengths of the transitions 9S_{ rm 1/2} - 8P _{rm 1/2,3/2} in the Ne ^{rm 7+*} agree with the best QED predictions by Johnson to within experimental error.

  8. Muon capture on the deuteron and the neutron-neutron scattering length

    NASA Astrophysics Data System (ADS)

    Marcucci, L. E.; Machleidt, R.

    2014-11-01

    Background: We consider the muon capture reaction ?-+2H???+n +n , which presents a "clean" two-neutron (n n ) system in the final state. We study here its capture rate in the doublet hyperfine initial state (?D). The total capture rate for the muon capture ?-+3He???+3H (?0) is also analyzed, although, in this case, the n n system is not so clean anymore. Purpose: We investigate whether ?D (and ?0) could be sensitive to the n n S -wave scattering length (an n), and we check on the possibility to extract an n from an accurate measurement of ?D. Method: The muon capture reactions are studied with nuclear potentials and charge-changing weak currents, derived within chiral effective field theory. The next-to-next-to-next-to-leading-order chiral potential with cutoff parameter ? =500 MeV is used, but the low-energy constant (LEC) determining an n is varied so as to obtain an n=-18.95 ,-16.0 ,-22.0 , and +18.22 fm. The first value is the present empirical one, while the last one is chosen such as to lead to a di-neutron bound system with a binding energy of 139 keV. The LEC's cD and cE, present in the three-nucleon potential and axial-vector current (cD), are constrained to reproduce the A =3 binding energies and the triton Gamow-Teller matrix element. Results: The capture rate ?D is found to be 399 (3 ) s-1 for an n=-18.95 and -16.0 fm; and 400 (3 ) s-1 for an n=-22.0 fm. However, in the case of an n=+18.22 fm, the result of 275 (3 ) s-1 [ 135 (3 ) s-1 ] is obtained, when the di-neutron system in the final state is unbound (bound). The total capture rate ?0 for muon capture on 3He is found to be 1494(15), 1491(16), 1488(18), and 1475(16) s-1 for an n=-18.95 ,-16.0 ,-22.0 , and +18.22 fm, respectively. All the theoretical uncertainties are due to the fitting procedure and radiative corrections. Conclusions: Our results seem to exclude the possibility of constraining a negative an n with an uncertainty of less than ˜±3 fm through an accurate determination of the muon capture rates, but the uncertainty on the present empirical value will not complicate the interpretation of the (forthcoming) experimental results for ?D. Finally, a comparison with the already available experimental data discourages the possibility of a bound di-neutron state (positive an n).

  9. The possible use of a spallation neutron source for neutron capture therapy with epithermal neutrons

    SciTech Connect

    Grusell, E.; Conde, H.; Larsson, B.; Roennqvist, T.S.; Sornsuntisook, O.; Crawford, J.; Reist, H.; Dahl, B.; Sjoestrand, N.G.R.; Russel, G. (Uppsala Univ. (Sweden))

    1990-01-01

    Spallation is induced in a heavy material by 72-MeV protons. The resulting neutrons can be characterized by an evaporation spectrum with a peak energy of less than 2 MeV. The neutrons are moderated in two steps: first in iron and then in carbon. Results from neutron fluence measurements in a perspex phantom placed close to the moderator are presented. Monte Carlo calculations of neutron fluence in a water phantom are also presented under some chosen configurations of spallation source and moderator. The calculations and measurements are in good agreement and show that, for proton currents of less than 0.5 mA, useful thermal-neutron fluences are attainable in the depth of the brain. However, the dose contribution from the unavoidable gamma background component has not been included in the present investigation.

  10. Computational characterization and experimental validation of the thermal neutron source for neutron capture therapy research at the University of Missouri

    SciTech Connect

    Broekman, J. D. [University of Missouri, Research Reactor Center, 1513 Research Park Drive, Columbia, MO 65211-3400 (United States); Nigg, D. W. [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415 (United States); Hawthorne, M. F. [University of Missouri, International Institute of Nano and Molecular Medicine, 1514 Research Park Dr., Columbia, MO 65211-3450 (United States)

    2013-07-01

    Parameter studies, design calculations and neutronic performance measurements have been completed for a new thermal neutron beamline constructed for neutron capture therapy cell and small-animal radiobiology studies at the University of Missouri Research Reactor. The beamline features the use of single-crystal silicon and bismuth sections for neutron filtering and for reduction of incident gamma radiation. The computational models used for the final beam design and performance evaluation are based on coupled discrete-ordinates and Monte Carlo techniques that permit detailed modeling of the neutron transmission properties of the filtering crystals with very few approximations. Validation protocols based on neutron activation spectrometry measurements and rigorous least-square adjustment techniques show that the beam produces a neutron spectrum that has the anticipated level of thermal neutron flux and a somewhat higher than expected, but radio-biologically insignificant, epithermal neutron flux component. (authors)

  11. Boron neutron capture therapy of primary and metastatic brain tumors.

    PubMed

    Barth, R F; Soloway, A H

    1994-01-01

    Boron neutron capture therapy (BNCT) is based on the nuclear reaction that occurs when a stable isotope, boron-10, is irradiated with low energy (0.025 eV) thermal neutrons (nth) to yield alpha (4He) particles and 7Li nuclei (10B+nth-->[11B]-->4He + 7Li + 2.79 MeV). The success of BNCT as a tumoricidal modality is dependent on the delivery of a sufficient quantity of 10B and nth to individual cancer cells to sustain a lethal 10B(n, alpha) 7Li reaction. Boron delivery agents include a variety of compounds, such as the sulfhydryl containing polyhedral borane sodium borocaptate (Na2B12H11SH, [BSH]), boronoporphyrins, boronophenylalanine, carboranyl uridines (CBU), and boronated monoclonal antibodies (MAb). The present review will focus on three delivery systems that currently are under investigation in our laboratories, boronated monoclonal antibodies, carboranyl uridines, and boronophenylalanine. Methodology has been developed to heavily boronate MAb using a precision macromolecule, a "starburst" dendrimer, which can be linked to MAb by means of heterobifunctional reagents. Although the resulting immunoconjugates retain their in vitro immunoreactivity, they lose their in vivo tumor localizing properties and accumulate in the liver. In order to obviate this problem, work is now in progress to produce bispecific MAb, which can simultaneously recognize a tumor-associated antigen and a boronated macromolecule. Boron containing nucleosides are potential vehicles for incorporating boron compounds into nucleic acids of neoplastic cells. For this purpose, carboranyl uridines have been synthesized with the boron moiety on either the pyrimidine base or on the carbohydrate component. Although such structures appear to be avidly taken up and retained by tumor cells in vitro, only the 5-carboranyl-nucleosides are converted biologically to the nucleotide. There is no evidence, however, that the latter are incorporated into nucleic acids. Other carboranyl nucleosides currently are being synthesized that may have better tumor localizing properties. The potential use of boronophenylalanine as a capture agent for the treatment of melanoma metastatic to the brain also is under investigation. A nude rat model has been developed using human melanoma cells that are stereotactically implanted into the brain. BNCT-treated animals have either had prolonged survival times or continue to live compared to control rats that invariably died of their tumors, thereby suggesting therapeutic efficacy. PMID:8086033

  12. MCNP speed advances for boron neutron capture therapy

    SciTech Connect

    Goorley, J.T.; McKinney, G.; Adams, K.; Estes, G.

    1998-04-01

    The Boron Neutron Capture Therapy (BNCT) treatment planning process of the Beth Israel Deaconess Medical Center-M.I.T team relies on MCNP to determine dose rates in the subject`s head for various beam orientations. In this time consuming computational process, four or five potential beams are investigated. Of these, one or two final beams are selected and thoroughly evaluated. Recent advances greatly decreased the time needed to do these MCNP calculations. Two modifications to the new MCNP4B source code, lattice tally and tracking enhancements, reduced the wall-clock run times of a typical one million source neutrons run to one hour twenty five minutes on a 200 MHz Pentium Pro computer running Linux and using the GNU FORTRAN compiler. Previously these jobs used a special version of MCNP4AB created by Everett Redmond, which completed in two hours two minutes. In addition to this 30% speedup, the MCNP4B version was adapted for use with Parallel Virtual Machine (PVM) on personal computers running the Linux operating system. MCNP, using PVM, can be run on multiple computers simultaneously, offering a factor of speedup roughly the same as the number of computers used. With two 200 MHz Pentium Pro machines, the run time was reduced to forty five minutes, a 1.9 factor of improvement over the single Linux computer. While the time of a single run was greatly reduced, the advantages associated with PVM derive from using computational power not already used. Four possible beams, currently requiring four separate runs, could be run faster when each is individually run on a single machine under Windows NT, rather than using Linux and PVM to run one after another with each multiprocessed across four computers. It would be advantageous, however, to use PVM to distribute the final two beam orientations over four computers.

  13. Boron neutron capture therapy at the crossroads: challenges and opportunities.

    PubMed

    Barth, Rolf F

    2009-07-01

    Over the past 25 years research on boron neutron capture therapy (BNCT) has progressed relatively slowly but steadily with the greatest progress in the field of clinical studies. These specifically have included the use of BNCT to treat a variety of malignancies other than high grade gliomas and melanomas. However, there are a number of key areas where little, if any, significant progress has been made. First and foremost among these has been the lack of new boron delivery agents. Improvement in drug delivery and the development of the best dosing paradigms for both boronophenylalanine (BPA) and sodium borocaptate (BSH) are of major importance and these still have not been optimized. Dosimetry for BNCT is still imprecise and is based on treating to normal tissue tolerance, based on blood boron values, rather than any real-time information on the boron content of the residual tumor that is to be irradiated. Another major problem has been the total dependence on nuclear reactors as neutron sources for BNCT. However, this will change in the near future when a clinically useful accelerator comes into use in 2009. Like it or not, in order to gain the credibility of a broad community of physicians who treat brain tumor patients, there will have to be a randomized clinical trial. Finally, BNCT will have to compete with new therapeutic approaches that are less costly and more effective for the treatment of brain tumors. These challenges notwithstanding, BNCT can fill an important niche for those malignancies, whether primary or recurrent, for which there is currently no effective therapy. PMID:19467879

  14. Study on High Speed Lithium Jet For Neutron Source of Boron Neutron Capture Therapy (BNCT)

    NASA Astrophysics Data System (ADS)

    Takahashi, Minoru; Kobayashi, Tooru; Zhang, Mingguang; Mák, Michael; Štefanica, Jirí; Dostál, Václav; Zhao, Wei

    The feasibility study of a liquid lithium type proton beam target was performed for the neutron source of the boron neutron capture therapy (BNCT). As the candidates of the liquid lithium target, a thin sheet jet and a thin film flow on a concave wall were chosen, and a lithium flow experiment was conducted to investigate the hydrodynamic stability of the targets. The surfaces of the jets and film flows with a thickness of 0.5 mm and a width of 50 mm were observed by means of photography. It has been found that a stable sheet jet and a stable film flow on a concave wall can be formed up to certain velocities by using a straight nozzle and a curved nozzle with the concave wall, respectively.

  15. General Electric PETtrace cyclotron as a neutron source for boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Bosko, Andrey

    This research investigates the use of a PETtrace cyclotron produced by General Electric (GE) as a neutron source for boron neutron capture therapy (BNCT). The GE PETtrace was chosen for this investigation because this type of cyclotron is popular among nuclear pharmacies and clinics in many countries; it is compact and reliable; it produces protons with energies high enough to produce neutrons with appropriate energy and fluence rate for BNCT and it does not require significant changes in design to provide neutrons. In particular, the standard PETtrace 18O target is considered. The cyclotron efficiency may be significantly increased if unused neutrons produced during radioisotopes production could be utilized for other medical modalities such as BNCT at the same time. The resulting dose from the radiation emitted from the target is evaluated using the Monte Carlo radiation transport code MCNP at several depths in a brain phantom for different scattering geometries. Four different moderating materials of various thicknesses were considered: light water, carbon, heavy water, arid Fluental(TM). The fluence rate tally was used to calculate photon and neutron dose, by applying fluence rate-to-dose conversion factors. Fifteen different geometries were considered and a 30-cm thick heavy water moderator was chosen as the most suitable for BNCT with the GE PETtrace cyclotron. According to the Brookhaven Medical Research Reactor (BMRR) protocol, the maximum dose to the normal brain is set to 12.5 RBEGy, which for the conditions of using a heavy water moderator, assuming a 60 muA beam current, would be reached with a treatment time of 258 min. Results showed that using a PETtrace cyclotron in this configuration provides a therapeutic ratio of about 2.4 for depths up to 4 cm inside a brain phantom. Further increase of beam current proposed by GE should significantly improve the beam quality or the treatment time and allow treating tumors at greater depths.

  16. Neutron capture cross section of 197Au: A standard for stellar nucleosynthesis

    Microsoft Academic Search

    W. Ratynski; F. Kaeppeler

    1988-01-01

    We have measured the neutron capture cross section of gold using the 7Li(p,n)7Be reaction for neutron production. This reaction not only provides the integrated neutron flux via the 7Be activity of the target, but also allows for the simulation of a Maxwellian neutron energy spectrum at kT=25 keV. As this spectrum is emitted in a forward cone of 120° opening

  17. Parity non-conserving effect in the neutron radiative capture reaction

    Microsoft Academic Search

    Y. Masuda; T. Adachi; S. Ishimoto; E. Kikutani; H. Koiso; K. Morimoto; A. Masaike

    1987-01-01

    Helicity dependence was observed for the resonance of the neutron radiative capture reaction of139La using a polarized neutron beam. The polarized neutron beam was produced by a dynamically polarized proton filter. The neutron polarization was about 70 % throughout the measurement. The preliminary result of the asymmetry in the?-ray count was (9.5±1.2) %. Experiments were also carried out for98Mo,108Pd and129Xe.

  18. Thermal neutron irradiation field design for boron neutron capture therapy of human explanted liver.

    PubMed

    Bortolussi, S; Altieri, S

    2007-12-01

    The selective uptake of boron by tumors compared to that by healthy tissue makes boron neutron capture therapy (BNCT) an extremely advantageous technique for the treatment of tumors that affect a whole vital organ. An example is represented by colon adenocarcinoma metastases invading the liver, often resulting in a fatal outcome, even if surgical resection of the primary tumor is successful. BNCT can be performed by irradiating the explanted organ in a suitable neutron field. In the thermal column of the Triga Mark II reactor at Pavia University, a facility was created for this purpose and used for the irradiation of explanted human livers. The neutron field distribution inside the organ was studied both experimentally and by means of the Monte Carlo N-particle transport code (MCNP). The liver was modeled as a spherical segment in MCNP and a hepatic-equivalent solution was used as an experimental phantom. In the as-built facility, the ratio between maximum and minimum flux values inside the phantom ((phi(max)/phi(min)) was 3.8; this value can be lowered to 2.3 by rotating the liver during the irradiation. In this study, the authors proposed a new facility configuration to achieve a uniform thermal neutron flux distribution in the liver. They showed that a phi(max)/phi(min) ratio of 1.4 could be obtained without the need for organ rotation. Flux distributions and dose volume histograms were reported for different graphite configurations. PMID:18196797

  19. Design of a californium-based epithermal neutron beam for neutron capture therapy.

    PubMed

    Yanch, J C; Kim, J K; Wilson, M J

    1993-08-01

    The potential of the spontaneously fissioning isotope, 252Cf, to provide epithermal neutrons for use in boron neutron capture therapy (BNCT) has been investigated using Monte Carlo simulation. The Monte Carlo code MCNP was used to design an assembly composed of a 26 cm long, 11 cm radius cylindrical D2O moderator followed by a 64 cm long Al filter. Lithium filters are placed between the moderator and the filter and between the Al and the patient. A reflector surrounding the moderator/filter assembly is required in order to maintain adequate therapy flux at the patient position. An ellipsoidal phantom composed of skull- and brain-equivalent material was used to determine the dosimetric effect of this beam. It was found that both advantage depths and advantage ratios compare very favourably with reactor and accelerator epithermal neutron sources. The dose rate obtainable, on the other hand, is 4.1 RBE cGy min-1, based on a very large (1.0 g) source of 252Cf. This dose rate is two to five times lower than those provided by existing reactor beams and can be viewed as a drawback of using 252Cf as a neutron source. Radioisotope sources, however, do offer the advantage of in-hospital installation. PMID:8367525

  20. An integrated design of an accelerator-based neutron source for boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Dobelbower, Michael Christian

    1997-07-01

    An Accelerator Based Neutron Source (ABNS) for Boron Neutron Capture Therapy (BNCT) was first proposed at The Ohio State University (OSU). Since the conception of the ABNS for BNCT, OSU has designed and optimized a moderator assembly based on in-air and in-phantom parameters. Additionally, the fabrication of the moderator assembly has commenced along with detailed analyses of the target and its heat removal system. In this dissertation, an integrated design of the ABNS is presented. This integrated design includes the high energy beam transport system (HEBT), the target and heat removal system (HRS), and the moderator assembly. In the integration process, a neutronic model of the HRS was developed and incorporated into the moderator assembly model. Additionally, a preliminary design of a HEBT system was developed that is compatible with both the HRS and the facility shielding. This dissertation also includes the completion of the fabrication of the moderator assembly and its experimental verification. The completion of the moderator assembly fabrication included the refabrication of the moderator and delimiter and the fabrication of the 6Li covering on the front of the moderator assembly. The experimental verification included neutron spectrum calculations and measurements in the irradiation port, and 3He detector response calculations and measurements in-phantom downstream of the moderator assembly.

  1. Comparison of statistical model calculations for stable isotope neutron capture

    NASA Astrophysics Data System (ADS)

    Beard, M.; Uberseder, E.; Crowter, R.; Wiescher, M.

    2014-09-01

    It is a well-observed result that different nuclear input models sensitively affect Hauser-Feshbach (HF) cross-section calculations. Less well-known, however, are the effects on calculations originating from nonmodel aspects, such as experimental data truncation and transmission function energy binning, as well as code-dependent aspects, such as the definition of level-density matching energy and the inclusion of shell correction terms in the level-density parameter. To investigate these aspects, Maxwellian-averaged neutron capture cross sections (MACS) at 30 keV have been calculated using the well-established statistical Hauser-Feshbach model codes talys and non-smoker for approximately 340 nuclei. For the same nuclei, MACS predictions have also been obtained using two new HF codes, cigar and sapphire. Details of these two codes, which have been developed to contain an overlapping set of identically implemented nuclear physics input models, are presented. It is generally accepted that HF calculations are valid to within a factor of 3. It was found that this factor is dependent on both model and nonmodel details, such as the coarseness of the transmission function energy binning and data truncation, as well as variances in details regarding the implementation of level-density parameter, backshift, matching energy, and giant dipole strength function parameters.

  2. Neutron Capture Cross Section Measurement of 151Sm at the CERN Neutron Time of Flight Facility (n_TOF)

    Microsoft Academic Search

    U. Abbondanno; G. Aerts; F. Alvarez-Velarde; H. Álvarez-Pol; S. Andriamonje; J. Andrzejewski; G. Badurek; P. Baumann; F. Becvár; J. Benlliure; E. Berthoumieux; F. Calviño; D. Cano-Ott; R. Capote; P. Cennini; V. Chepel; E. Chiaveri; N. Colonna; G. Cortes; D. Cortina; A. Couture; J. Cox; S. Dababneh; M. Dahlfors; S. David; R. Dolfini; C. Domingo-Pardo; I. Duran; M. Embid-Segura; L. Ferrant; A. Ferrari; R. Ferreira-Marques; H. Frais-Koelbl; W. Furman; I. Goncalves; R. Gallino; E. Gonzalez-Romero; A. Goverdovski; F. Gramegna; E. Griesmayer; F. Gunsing; B. Haas; R. Haight; M. Heil; A. Herrera-Martinez; S. Isaev; E. Jericha; F. Käppeler; Y. Kadi; D. Karadimos; M. Kerveno; V. Ketlerov; P. Koehler; V. Konovalov; M. Krticka; C. Lamboudis; H. Leeb; A. Lindote; I. Lopes; M. Lozano; S. Lukic; J. Marganiec; S. Marrone; J. Martinez-Val; P. Mastinu; A. Mengoni; P. M. Milazzo; A. Molina-Coballes; C. Moreau; M. Mosconi; F. Neves; H. Oberhummer; S. O'Brien; J. Pancin; T. Papaevangelou; C. Paradela; A. Pavlik; P. Pavlopoulos; J. M. Perlado; L. Perrot; M. Pignatari; R. Plag; A. Plompen; A. Plukis; A. Poch; A. Policarpo; C. Pretel; J. Quesada; S. Raman; W. Rapp; T. Rauscher; R. Reifarth; M. Rosetti; C. Rubbia; G. Rudolf; P. Rullhusen; J. Salgado; J. C. Soares; C. Stephan; G. Tagliente; J. Tain; L. Tassan-Got; L. Tavora; R. Terlizzi; G. Vannini; P. Vaz; A. Ventura; D. Villamarin; M. C. Vincente; V. Vlachoudis; F. Voss; H. Wendler; M. Wiescher; K. Wisshak

    2004-01-01

    The151Sm(n,gamma)152Sm cross section has been measured at the spallation neutron facility n_TOF at CERN in the energy range from 1eV to 1MeV. The new facility combines excellent resolution in neutron time-of-flight, low repetition rates, and an unsurpassed instantaneous luminosity, resulting in rather favorable signal\\/background ratios. The 151Sm cross section is of importance for characterizing neutron capture nucleosynthesis in asymptotic giant

  3. Accelerator-based epithermal neutron sources for boron neutron capture therapy of brain tumors.

    PubMed

    Blue, Thomas E; Yanch, Jacquelyn C

    2003-01-01

    This paper reviews the development of low-energy light ion accelerator-based neutron sources (ABNSs) for the treatment of brain tumors through an intact scalp and skull using boron neutron capture therapy (BNCT). A major advantage of an ABNS for BNCT over reactor-based neutron sources is the potential for siting within a hospital. Consequently, light-ion accelerators that are injectors to larger machines in high-energy physics facilities are not considered. An ABNS for BNCT is composed of: (1) the accelerator hardware for producing a high current charged particle beam, (2) an appropriate neutron-producing target and target heat removal system (HRS), and (3) a moderator/reflector assembly to render the flux energy spectrum of neutrons produced in the target suitable for patient irradiation. As a consequence of the efforts of researchers throughout the world, progress has been made on the design, manufacture, and testing of these three major components. Although an ABNS facility has not yet been built that has optimally assembled these three components, the feasibility of clinically useful ABNSs has been clearly established. Both electrostatic and radio frequency linear accelerators of reasonable cost (approximately 1.5 M dollars) appear to be capable of producing charged particle beams, with combinations of accelerated particle energy (a few MeV) and beam currents (approximately 10 mA) that are suitable for a hospital-based ABNS for BNCT. The specific accelerator performance requirements depend upon the charged particle reaction by which neutrons are produced in the target and the clinical requirements for neutron field quality and intensity. The accelerator performance requirements are more demanding for beryllium than for lithium as a target. However, beryllium targets are more easily cooled. The accelerator performance requirements are also more demanding for greater neutron field quality and intensity. Target HRSs that are based on submerged-jet impingement and the use of microchannels have emerged as viable target cooling options. Neutron fields for reactor-based neutron sources provide an obvious basis of comparison for ABNS field quality. This paper compares Monte Carlo calculations of neutron field quality for an ABNS and an idealized standard reactor neutron field (ISRNF). The comparison shows that with lithium as a target, an ABNS can create a neutron field with a field quality that is significantly better (by a factor of approximately 1.2, as judged by the relative biological effectiveness (RBE)-dose that can be delivered to a tumor at a depth of 6cm) than that for the ISRNF. Also, for a beam current of 10 mA, the treatment time is calculated to be reasonable (approximately 30 min) for the boron concentrations that have been assumed. PMID:12749700

  4. Determination and production of an optimal neutron energy spectrum for boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Bleuel, Darren Leo

    An accelerator-based neutron irradiation facility employing an electrostatic quadrupole (ESQ) accelerator for Boron Neutron Capture Therapy (BNCT) has been proposed at Lawrence Berkeley National Laboratory. In this dissertation, the properties of an ideal neutron beam for delivering a maximized dose to a glioblastoma multiforme tumor in a reasonable time while minimizing the dose to healthy tissue is examined. A variety of materials, beam shaping assemblies, and neutron sources were considered to deliver a neutron spectrum as close to the calculated idealized spectrum as possible. Several optimization studies were performed to determine the best proton energy and moderator material to maximize the efficacy of an accelerator-based BNCT facility utilizing the 7Li(p,n)7Be reaction as a neutron source. A new, faster method of performing such an optimization was developed, known as the "Ubertally" method, in which data from a single Monte Carlo simulation is reweighted to produce results for any neutron spatial, energy and angular source distribution. Results were confirmed experimentally at Lawrence Berkeley National Laboratory's 88? cyclotron. Thermal fluxes in this experiment were found to be approximately 30% lower than expected, but the depth-dose profile was confirmed to within 8% maximum deviation. A final beam shaping assembly is then recommended. Utilizing a material known as Fluental as a moderating material, deep-seated tumor doses 50% higher than that delivered by clinical trials at the Brookhaven Medical Research Reactor (BMRR) are predicted. The final recommended design should contain a 37 cm thickness of Fluental(TM) moderator, a 1--2 cm gamma shield, an Al2O3 reflector, a V-shaped aluminum-backed or copper-backed source with heavy water cooling, and a 13 cm lithiated polyethylene delimiter. This design would be operated at 2.4 MeV proton energy at 20 mA to conduct treatments in less than an hour and a half. However, this design may be easily altered depending on the changing needs of the treatment facility. It is therefore concluded that production of an accelerator-based BNCT facility using an ESQ accelerator and a 7Li target is feasible and can produce a superior quality neutron beam.

  5. Mixed field dosimetry of epithermal neutron beams for boron neutron capture therapy at the MITR-II research reactor

    SciTech Connect

    Rogus, R.D.; Harling, O.K.; Yanch, J.C. (Massachusetts Institute of Technology, Nuclear Reactor Laboratory, Cambridge, Massachusetts 02139 (United States))

    1994-10-01

    During the past several years, there has been growing interest in Boron Neutron Capture Therapy (BNCT) using epithermal neutron beams. The dosimetry of these beams is challenging. The incident beam is comprised mostly of epithermal neutrons, but there is some contamination from photons and fast neutrons. Within the patient, the neutron spectrum changes rapidly as the incident epithermal neutrons scatter and thermalize, and a photon field is generated from neutron capture in hydrogen. In this paper, a method to determine the doses from thermal and fast neutrons, photons, and the B-10([ital n],[alpha])Li-7 reaction is presented. The photon and fast neutron doses are measured with ionization chambers, in realistic phantoms, using the dual chamber technique. The thermal neutron flux is measured with gold foils using the cadmium difference technique; the thermal neutron and B-10 doses are determined by the kerma factor method. Representative results are presented for a unilateral irradiation of the head. Sources of error in the method as applied to BNCT dosimetry, and the uncertainties in the calculated doses are discussed.

  6. Mixed field dosimetry of epithermal neutron beams for boron neutron capture therapy at the MITR-II research reactor.

    PubMed

    Rogus, R D; Harling, O K; Yanch, J C

    1994-10-01

    During the past several years, there has been growing interest in Boron Neutron Capture Therapy (BNCT) using epithermal neutron beams. The dosimetry of these beams is challenging. The incident beam is comprised mostly of epithermal neutrons, but there is some contamination from photons and fast neutrons. Within the patient, the neutron spectrum changes rapidly as the incident epithermal neutrons scatter and thermalize, and a photon field is generated from neutron capture in hydrogen. In this paper, a method to determine the doses from thermal and fast neutrons, photons, and the B-10(n, alpha)Li-7 reaction is presented. The photon and fast neutron doses are measured with ionization chambers, in realistic phantoms, using the dual chamber technique. The thermal neutron flux is measured with gold foils using the cadmium difference technique, the thermal neutron and B-10 doses are determined by the kerma factor method. Representative results are presented for a unilateral irradiation of the head. Sources of error in the method as applied to BNCT dosimetry, and the uncertainties in the calculated doses are discussed. PMID:7869994

  7. Development of a gamma ray telescope for online synovial dosimetry in boron neutron capture synovectomy

    E-print Network

    Jiang, Hongyu, 1971-

    2003-01-01

    Boron Neutron Capture Synovectomy (BNCS) is a novel application of the ¹?B(n,?) reaction for potential treatment of rheumatoid arthritis. During BNCS clinical trials, real-time knowledge of boron dose delivered to the ...

  8. Thiourea derivatives, methods of their preparation and their use in neutron capture therapy of malignant melanoma

    DOEpatents

    Gabel, D.

    1991-06-04

    The present invention pertains to boron containing thiouracil derivatives, their method of preparations, and their use in the therapy of malignant melanoma using boron neutron capture therapy. No Drawings

  9. Boron containing compounds and their preparation and use in neutron capture therapy

    DOEpatents

    Gabel, D.

    1992-09-01

    The present invention pertains to boron containing thiouracil derivatives, their method of preparations, and their use in the therapy of malignant melanoma using boron neutron capture therapy. No Drawings

  10. Measurement of the thermal neutron distribution in a water phantom using a cyclotron based neutron source for boron neutron capture therapy

    Microsoft Academic Search

    Hiroki Tanaka; Yoshinori Sakurai; Minoru Suzuki; Shinichiro Masunaga; Toshinori Mitsumoto; Satoru Yajima; Hiroshi Tsutsui; Takemi Sato; Tomoyuki Asano; Genro Kashino; Yuko Kinashi; Yong Liu; Koji Ono; A. Maruhashi

    2009-01-01

    We have been developed an epithermal neutron source for boron neutron capture therapy(BNCT), consisting of a cyclotron accelerator that can provide a ~ 1 mA, 30 MeV proton beam, a neutron production beryllium target and the moderator that can reduce the energy of fast neutrons to an effective energy range. In order to validate the simulations, we measured the depth

  11. Carboranyl Nucleosides & Oligonucleotides for Neutron Capture Therapy Final Report

    SciTech Connect

    Schinazi, Raymond F.

    2004-12-01

    This proposal enabled us to synthesize and develop boron-rich nucleosides and oligonucleotide analogues for boron neutron capture therapy (BNCT) and the treatment of various malignancies. First, we determined the relationship between structure, cellular accumulation and tissue distribution of 5-o-carboranyl-2'-deoxyuridine (D-CDU) and its derivatives D-ribo-CU and 5-o-carboranyluracil (CU), to potentially target brain and other solid tumors for neutron capture therapy. Synthesized carborane containing nucleoside derivatives of CDU, D- and L-enantiomers of CDU, D-ribo-CU and CU were used. We measured tissue disposition in xenografted mice bearing 9479 human prostate tumors xenografts and in rats bearing 9L gliosarcoma isografts in their flanks and intracranially. The accumulation of D-CDU, 1-({beta}-L-arabinosyl)-5-o-carboranyluracil, D-ribo-CU, and CU were also studied in LnCap human prostate tumor cells and their retention was measured in male nude mice bearing LnCap and 9479 human prostate tumor xenografts. D-CDU, D-ribo-CU and CU levels were measured after administration in mice bearing 9479 human prostate tumors in their flanks. D-CDU achieved high cellular concentrations in LnCap cells and up to 2.5% of the total cellular compound was recovered in the 5'-monophosphorylated form. D-CDU cellular concentrations were similar in LnCap and 9479 tumor xenografts. Studies in tumor bearing animals indicated that increasing the number of hydroxyl moieties in the sugar constituent of the carboranyl nucleosides lead to increased rate and extent of renal elimination, a decrease in serum half-lives and an increased tissue specificity. Tumor/brain ratios were greatest for CDU and D-ribo-CU, while tumor/prostate ratios were greatest with CU. CDU and D-ribo-CU have potential for BNCT of brain malignancies, while CU may be further developed for prostate cancer. A method was developed for the solid phase synthesis of oligonucleotides containing (ocarboran-1-yl-methyl)phosphonate (CBMP) internucleotide group. Unmodified phosphodiester linkages were formed using a standard {beta}-cyanoethyl cycle and automated DNA synthesizer. Modified CBMP internucleotide linkage was produced using the phosphotriester method and 5'-O-monomethoxytritylthymidine 3'-O-[(o-carboran-1-yl-methyl)phosphonate] monomer. Several dodecathymidylic acids bearing modification at 3'- or 5'-end, or in the middle of oligonucleotide chain were synthesized. The resulting oligomers are being characterized by reverse phase high-pressure liquid chromatography (RP-HPLC), electrospray ionization mass spectrometry (ESIMS), ultraviolet spectroscopy (UV), and circular dichroism (CD). In collaboration with Cornell University, we employed a secondary ion mass spectrometry (SIMS) based subcellular isotopic imaging technique of ion microscopy for evaluating 4 carboranyl nucleosides. Nucleosides synthesized by our group, including CDU, HMCDU, CTU, and CFAU were tested for their boron delivery to the nuclear and cytoplasmic compartments of U251 human and F98 rat glioma cells. Quantitative SIMS analysis of boron was performed in cryogenically prepared cells. For all drugs, the cell cytoplasm revealed significantly higher boron than the nucleus. However, the boron partitioning between the cell nucleus and the nutrient medium indicated 6.4-10.6 times higher boron in the nucleus. The results suggested that these novel carboranyl nucleosides should provide efficient BNCT agents that accumulate in malignant cells and the need for further evaluations in vitro and in animal models.

  12. (A clinical trial of neutron capture therapy for brain tumors)

    SciTech Connect

    Zamenhof, R.G.

    1988-01-01

    This report describes progress made in refining of neutron-induced alpha tract autoradiography, in designing epithermal neutron bean at MITR-II and in planning treatment dosimetry using Monte Carlo techniques.

  13. A Project of Boron Neutron Capture Therapy System based on a Proton Linac Neutron Source

    NASA Astrophysics Data System (ADS)

    Kiyanagi, Yoshikai; Asano, Kenji; Arakawa, Akihiro; Fukuchi, Shin; Hiraga, Fujio; Kimura, Kenju; Kobayashi, Hitoshi; Kubota, Michio; Kumada, Hiroaki; Matsumoto, Hiroshi; Matsumoto, Akira; Sakae, Takeji; Saitoh, Kimiaki; Shibata, Tokushi; Yoshioka, Masakazu

    At present, the clinical trials of Boron Neutron Capture Therapy (BNCT) are being performed at research reactor facilities. However, an accelerator based BNCT has a merit that it can be built in a hospital. So, we just launched a development project for the BNCT based on an accelerator in order to establish and to spread the BNCT as an effective therapy in the near future. In the project, a compact proton linac installed in a hospital will be applied as a neutron source, and energy of the proton beam is planned to be less than about 10 MeV to reduce the radioactivity. The BNCT requires epithermal neutron beam with an intensity of around 1x109 (n/cm2/sec) to deliver the therapeutic dose to a deeper region in a body and to complete the irradiation within an hour. From this condition, the current of the proton beam required is estimated to be a few mA on average. Enormous heat deposition in the target is a big issue. We are aiming at total optimization of the accelerator based BNCT from the linac to the irradiation position. Here, the outline of the project is introduced and the moderator design is presented.

  14. Boron neutron capture therapy (BNCT): Implications of neutron beam and boron compound characteristics

    SciTech Connect

    Wheeler, F.J.; Nigg, D.W. [Center for Advanced Radiation Therapies, Idaho National Engineering and Environmental Laboratory, P.O. Box 1625, Idaho Falls, Idaho 83415-3890 (United States)] [Center for Advanced Radiation Therapies, Idaho National Engineering and Environmental Laboratory, P.O. Box 1625, Idaho Falls, Idaho 83415-3890 (United States); Capala, J. [Medical Department, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)] [Medical Department, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Watkins, P.R.; Vroegindeweij, C. [HFR Unit, Joint Research Centre, Commission of the European Communities, Petten, (Netherlands) NL-1755 ZG] [HFR Unit, Joint Research Centre, Commission of the European Communities, Petten, (Netherlands) NL-1755 ZG; Auterinen, I. [VTT Chemical Technology, Technical Research Centre of Finland, Reactor Laboratory, Espoo, (Finland) FIN-02044] [VTT Chemical Technology, Technical Research Centre of Finland, Reactor Laboratory, Espoo, (Finland) FIN-02044; Seppaelae, T. [Department of Physics, University of Helsinki, Helsinki, (Finland) FIN-00014] [Department of Physics, University of Helsinki, Helsinki, (Finland) FIN-00014; Bleuel, D. [E. O. Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [E. O. Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    1999-07-01

    The potential efficacy of boron neutron capture therapy (BNCT) for malignant glioma is a significant function of epithermal-neutron beam biophysical characteristics as well as boron compound biodistribution characteristics. Monte Carlo analyses were performed to evaluate the relative significance of these factors on theoretical tumor control using a standard model. The existing, well-characterized epithermal-neutron sources at the Brookhaven Medical Research Reactor (BMRR), the Petten High Flux Reactor (HFR), and the Finnish Research Reactor (FiR-1) were compared. Results for a realistic accelerator design by the E. O. Lawrence Berkeley National Laboratory (LBL) are also compared. Also the characteristics of the compound {ital p}-Boronophenylaline Fructose (BPA-F) and a hypothetical next-generation compound were used in a comparison of the BMRR and a hypothetical improved reactor. All components of dose induced by an external epithermal-neutron beam fall off quite rapidly with depth in tissue. Delivery of dose to greater depths is limited by the healthy-tissue tolerance and a reduction in the hydrogen-recoil and incident gamma dose allow for longer irradiation and greater dose at a depth. Dose at depth can also be increased with a beam that has higher neutron energy (without too high a recoil dose) and a more forward peaked angular distribution. Of the existing facilities, the FiR-1 beam has the better quality (lower hydrogen-recoil and incident gamma dose) and a penetrating neutron spectrum and was found to deliver a higher value of Tumor Control Probability (TCP) than other existing beams at shallow depth. The greater forwardness and penetration of the HFR the FiR-1 at greater depths. The hypothetical reactor and accelerator beams outperform at both shallow and greater depths. In all cases, the hypothetical compound provides a significant improvement in efficacy but it is shown that the full benefit of improved compound is not realized until the neutron beam is fully optimized. {copyright} {ital 1999 American Association of Physicists in Medicine.}

  15. New compounds for neutron capture therapy (NCT) and their significance

    SciTech Connect

    Fairchild, R.G.; Bond, V.P.

    1982-01-01

    Clearly the most effective tumor therapy would be obtained by the selective targeting of cytotoxic agents to tumor cells. Although many biomolecules are known to be taken up in tumors, the targeting of cytotoxic agents to tumors is limited by the fact that other essential cell pools compete with equal or even greater effectiveness. The approach of delivering stable non-toxic isotopes to tumor, with activation by means of an external radiation beam, is advantageous for two reasons: (1) it obviates problems associated with high uptake of isotopes in normal tissues, as these cell pools can be excluded from the radiation field, and (2) the general tumor area can be included in the activating beam field; thus, the possibility exists that all microscopic tumor extensions can be irradiated. As long as range of reaction products is short, dose will be restricted to the tumor, with a resultant high therapeutic ratio. This method can be accomplished with either photon activation therapy (PAT) or Neutron Capture Therapy (NCT), the latter will be emphasized here. The range of the high LET, low OER particles from the /sup 10/B(n,..cap alpha..)/sup 7/Li reaction is approx. 10 ..mu..m, or one cell diameter; hence this reaction is optimal for cell killing. A number of biomolecules have been investigated as possible vehicles for transport of boron to tumors, including phenothiazines, thiouracils, porphyrins, nucleosides, and amino acids. Biodistributions of these compounds show selective concentration in tumor adequate for therapy. The biological halflives are in the order of days, allowing the possibility of fractionated or protracted irradiations. The radiobiological and physical implication of these parameters on NCT are discussed. The possibility of using an approximately-monoenergetic, scandium-filtered beam of about 2 keV, to reduce the dose from background radiations by about 85%, is also discussed. (ERB)

  16. Convection enhanced delivery of carboranylporphyrins for neutron capture therapy of brain tumors

    Microsoft Academic Search

    Shinji Kawabata; Weilian Yang; Rolf F. Barth; Gong Wu; Tianyao Huo; Peter J. Binns; Kent J. Riley; Owendi Ongayi; Vijay Gottumukkala; M. Graça H. Vicente

    2011-01-01

    Boron neutron capture therapy (BNCT) is based on the nuclear capture and fission reactions that occur when non-radioactive\\u000a 10B is irradiated with low energy thermal neutrons to produce ?-particles (10B[n,?]7Li). Carboranylporphyrins are a class of substituted porphyrins containing multiple carborane clusters. Three of these compounds,\\u000a designated H2TBP, H2TCP, and H2DCP, have been evaluated in the present study. The goals were

  17. Low-energy level structure of 151Sm by neutron capture reactions and theoretical interpretation

    Microsoft Academic Search

    G. Vandenput; P. H. M. van Assche; L. Jacobs; J. M. van den Cruyce; R. K. Smither; K. Schreckenbach; T. von Egidy; D. Breitig; H. A. Baader; H. R. Koch

    1986-01-01

    A nuclear structure study of 151Sm is presented on the basis of low-energy gamma-ray and conversion electron spectroscopy, in connection with thermal neutron capture, and high-energy primary gamma-ray measurements following average resonance neutron capture. The level scheme is established up to 1020 keV and incorporates 44 levels. Unique spin and parity assignments are made for 34 levels, and narrow limits

  18. Stellar neutron capture cross section of the unstable s-process branching point 151Sm

    Microsoft Academic Search

    K. Wisshak; F. Voss; F. Kaeppeler; M. Krticka; S. Raman; A. Mengoni; R. Gallino

    2006-01-01

    The neutron capture cross sections of the radioactive isotope 151Sm and of natural samarium have been measured in the energy range from 3 keV to 225 keV at the Karlsruhe 3.7 MV Van de Graaff accelerator. Neutrons were produced via the 7Li(p,n)7Be reaction by bombarding metallic Li targets with a pulsed proton beam and capture events were registered with the

  19. Initial Performance Characterization for a Thermalized Neutron Beam for Neutron Capture Therapy Research at Washington State University

    SciTech Connect

    David W. Nigg; P.E> Sloan; J.R. Venhuizen; C.A. Wemple

    2005-11-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) and Washington State University (WSU) have constructed a new epithermal-neutron beam for collaborative Boron Neutron Capture Therapy (BNCT) preclinical research at the WSU TRIGATM research reactor facility1. More recently, additional beamline components were developed to permit the optional thermalization of the beam for certain types of studies where it is advantageous to use a thermal neutron source rather than an epithermal source. This article summarizes the results of some initial neutronic performance measurements for the thermalized system, with a comparison to the expected performance from the design computations.

  20. Conceptual physics design of an epithermal-neutron facility for neutron capture therapy at the Georgia Tech research reactor

    SciTech Connect

    Nigg, D.W.; Wheeler, F.J. (Idaho National Engineering Lab., Idaho Falls (United States))

    1992-01-01

    The Idaho National Engineering Laboratory (INEL) is currently the focus for a comprehensive program directed toward the development of boron neutron capture therapy (BNCT) for certain types of refractory malignancies. One particular component of the INEL BNCT program involves a collaborative effort between the INEL and Georgia Institute of Technology to design an advanced epithermal- (neutrons in the energy range of 0.5 eV to 10 keV) neutron beam facility for BNCT research at the Georgia Tech research reactor (GTRR). The basic conceptual design and expected physics-related performance parameters for the GTRR epithermal-neutron beam are presented in this paper.

  1. Design and optimization of 6li neutron-capture pulse mode ion chamber 

    E-print Network

    Chung, Kiwhan

    2009-05-15

    The purpose of this research is to design and optimize the performance of a unique, inexpensive 6Li neutron-capture pulse-mode ion chamber (LiPMIC) for neutron detection that overcomes the fill-gas contamination stemming from outgas of detector...

  2. The rationale and requirements for the development of boron neutron capture therapy of brain tumors

    Microsoft Academic Search

    Albert H. Soloway; Rolf F. Barth; Reinhard A. Gahbauer; Thomas E. Blue; Joseph H. Goodman

    1997-01-01

    The dismal clinical results in the treatment ofglioblastoma multiforme despite aggressive surgery, conventional radiotherapy, andchemotherapy, either alone or in combination has ledto the development of alternative therapeutic modalities. Amongthese is boron neutron capture therapy (BNCT). Thisbinary system is based upon two key requirements:(1) the development and use of neutron beamsfrom nuclear reactors or other sources with thecapability for delivering high

  3. Neutron Capture Cross Section Measurement on 91Zr at J-PARC/MLF/ANNRI

    NASA Astrophysics Data System (ADS)

    Hori, Jun-ichi; Yashima, Hiroshi; Nakamura, Shoji; Furutaka, Kazuyoshi; Hara, Kaoru Y.; Harada, Hideo; Hirose, Kentaro; Igashira, Masayuki; Katabuchi, Tatsuya; Kimura, Atsushi; Kino, Koichi; Kitatani, Fumito; Kiyanagi, Yoshiaki; Koizumi, Mitsuo; Mizumoto, Motoharu; Sano, Tadafumi; Takahashi, Yoshiyuki; Toh, Yosuke

    2015-05-01

    The neutron capture cross section measurement on 91Zr was performed at neutron TOF beam line ANNRI installed at J-PARC/MLF. Prompt capture gamma rays from the sample were detected with an array of large Ge detectors at a distance of 21.5 m from the spallation neutron source by the time-of-fligh (TOF) method. The neutron capture gamma-ray pulse-height spectra from the 182-eV p-wave resonance and the 292-eV s-wave resonance were obtained by gating on the TOF regions, respectively. Though the decay patterns of primary transitions from the capture state were quite different between resonances, the prominent characteristics common to both resonances was the very strong ground-state transition from the 935-keV state. Therefore, a ground-state transition method was applied to obtain the capture yield, so that the background components due to impurities were successfully eliminated. The preliminary result of the neutron capture cross section for 91Zr up to 5 keV is presented.

  4. Measurements of neutron capture cross section for {sup 207,208}Pb

    SciTech Connect

    Segawa, M.; Toh, Y.; Harada, H.; Kitatani, F.; Koizumi, M.; Fukahori, T.; Iwamoto, N.; Iwamoto, O. [Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Oshima, M. [Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan and Japan Chemical Analysis Center (Japan); Hatsukawa, Y. [Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Nagai, Y. [Research Center for Nuclear Physics, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Igashira, M. [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo 152-8550 (Japan); Kamada, S. [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo 152-8550, Japan and National Maritime Research Institute (Japan); Tajika, M. [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo 152-8550, Japan and Hitachi Solutions, Ltd. (Japan)

    2014-05-02

    The neutron capture cross sections for {sup 207,208}Pb have been measured in the neutron energy region from 10 to 110 keV. The ?-rays cascaded from a capture state to the ground state or low-lying states of {sup 208,209}Pb were observed for the first time, using an anti-Compton Nal(Tl) spectrometer and a TOF method. The observed discrete ?-ray energy spectra enabled us to determine neutron capture cross sections for {sup 207,208}Pb with small systematic errors, since we could distinguish ?-ray of {sup 207,208}Pb(n,?) reactions from background ?-ray with use of the ?-ray spectra. The obtained cross sections include both contributions of resonance and direct capture components different from the previous TOF measurements.

  5. Measurements of neutron capture cross section for 207,208Pb

    NASA Astrophysics Data System (ADS)

    Segawa, M.; Toh, Y.; Harada, H.; Kitatani, F.; Koizumi, M.; Fukahori, T.; Oshima, M.; Iwamoto, N.; Iwamoto, O.; Hatsukawa, Y.; Nagai, Y.; Igashira, M.; Kamada, S.; Tajika, M.

    2014-05-01

    The neutron capture cross sections for 207,208Pb have been measured in the neutron energy region from 10 to 110 keV. The ?-rays cascaded from a capture state to the ground state or low-lying states of 208,209Pb were observed for the first time, using an anti-Compton Nal(Tl) spectrometer and a TOF method. The observed discrete ?-ray energy spectra enabled us to determine neutron capture cross sections for 207,208Pb with small systematic errors, since we could distinguish ?-ray of 207,208Pb(n,?) reactions from background ?-ray with use of the ?-ray spectra. The obtained cross sections include both contributions of resonance and direct capture components different from the previous TOF measurements.

  6. Evaluation of useful neutron flux for accelerator boron neutron capture therapy using the 7Li(p,n) reaction.

    PubMed

    Zimin, S; Allen, B J

    1998-12-01

    Accelerator neutron sources for epithermal neutron capture therapy utilising the 7Li(p,n) nuclear reaction are proposed to operate in the range of 1.88 to 2.5 MeV proton energy. Operation with proton energies closer to the reaction threshold decreases neutron yield but allows for smaller reflector and moderator, with less reduction of the epithermal flux, whereas high energies allow thicker targets to be used. The neutron yields for thick lithium targets are estimated in the energy range of 1.881 MeV to 2.5 MeV and useful neutron flux determined. The optimal range of proton energy is found to be 1.89-1.95 MeV, and this is recommended for more detailed studies of neutron transport properties for accelerator BNCT. PMID:10050350

  7. Dose evaluation of boron neutron capture synovectomy using the THOR epithermal neutron beam: a feasibility study.

    PubMed

    Wu, Jay; Chang, Shu-Jun; Chuang, Keh-Shih; Hsueh, Yen-Wan; Yeh, Kuan-Chuan; Wang, Jeng-Ning; Tsai, Wen-Pin

    2007-03-21

    Rheumatoid arthritis is one of the most common epidemic diseases in the world. For some patients, the treatment with steroids or nonsteroidal anti-inflammatory drugs is not effective, thus necessitating physical removal of the inflamed synovium. Alternative approaches other than surgery will provide appropriate disease control and improve the patient's quality of life. In this research, we evaluated the feasibility of conducting boron neutron capture synovectomy (BNCS) with the Tsing Hua open-pool reactor (THOR) as a neutron source. Monte Carlo simulations were performed with arthritic joint models and uncertainties were within 5%. The collimator, reflector and boron concentration were optimized to reduce the treatment time and normal tissue doses. For the knee joint, polyethylene with 40%-enriched Li(2)CO(3) was used as the collimator material, and a rear reflector of 15 cm thick graphite and side reflector of 10 cm thick graphite were chosen. The optimized treatment time was 5.4 min for the parallel-opposed irradiation. For the finger joint, polymethyl methacrylate was used as the reflector material. The treatment time can be reduced to 3.1 min, while skin and bone doses can be effectively reduced by approximately 9% compared with treatment using the graphite reflector. We conclude that using THOR as a treatment modality for BNCS could be a feasible alternative in clinical practice. PMID:17327660

  8. Boron Neutron-Capture Therapy (BNCT) for Glioblastoma Multiforme (GBM) Using the Epithermal Neutron Beam at the Brookhaven National Laboratory

    Microsoft Academic Search

    Manjeet Chadha; Jacek Capala; Jeffrey A Coderre; Eric H Elowitz; Jun-ichi Iwai; Darrel D Joel; Hungyuan B Liu; Lucian Wielopolski; Arjun D Chanana

    1998-01-01

    Objective: Boron neutron-capture therapy (BNCT) is a binary form of radiation therapy based on the nuclear reactions that occur when boron (10B) is exposed to thermal neutrons. Preclinical studies have demonstrated the therapeutic efficacy of p-boronophenylalanine (BPA)-based BNCT. The objectives of the Phase I\\/II trial were to study the feasibility and safety of single-fraction BNCT in patients with GBM.Materials and

  9. Basic investigation of boron neutron capture therapy (BNCT) using novel boron agents and accelerator based neutron source

    Microsoft Academic Search

    M. Sakai; N. Fujimoto; K. Ishii; I. Murata; C. M. Lee; Y. Kaneda; H. Nakamura; K. Awazu

    Recently the number of cancer case has been increasing. In addition, because of aging of the population and diversification\\u000a of values among the people, less-invasive and high-QOL (quality of life) treatment for tumors has been needed. BNCT (Boron\\u000a Neutron Capture Therapy) is based on the nuclear reaction of two essentially nontoxic species, 10B and thermal neutron. BNCT is effective and

  10. A study on the optimum fast neutron flux for boron neutron capture therapy of deep-seated tumors.

    PubMed

    Rasouli, Fatemeh S; Masoudi, S Farhad

    2015-02-01

    High-energy neutrons, named fast neutrons which have a number of undesirable biological effects on tissue, are a challenging problem in beam designing for Boron Neutron Capture Therapy, BNCT. In spite of this fact, there is not a widely accepted criterion to guide the beam designer to determine the appropriate contribution of fast neutrons in the spectrum. Although a number of researchers have proposed a target value for the ratio of fast neutron flux to epithermal neutron flux, it can be shown that this criterion may not provide the optimum treatment condition. This simulation study deals with the determination of the optimum contribution of fast neutron flux in the beam for BNCT of deep-seated tumors. Since the dose due to these high-energy neutrons damages shallow tissues, delivered dose to skin is considered as a measure for determining the acceptability of the designed beam. To serve this purpose, various beam shaping assemblies that result in different contribution of fast neutron flux are designed. The performances of the neutron beams corresponding to such configurations are assessed in a simulated head phantom. It is shown that the previously used criterion, which suggests a limit value for the contribution of fast neutrons in beam, does not necessarily provide the optimum condition. Accordingly, it is important to specify other complementary limits considering the energy of fast neutrons. By analyzing various neutron spectra, two limits on fast neutron flux are proposed and their validity is investigated. The results show that considering these limits together with the widely accepted IAEA criteria makes it possible to have a more realistic assessment of sufficiency of the designed beam. Satisfying these criteria not only leads to reduction of delivered dose to skin, but also increases the advantage depth in tissue and delivered dose to tumor during the treatment time. The Monte Carlo Code, MCNP-X, is used to perform these simulations. PMID:25479433

  11. Neutron transmission and capture cross section measurements for 241Am at the GELINA facility

    NASA Astrophysics Data System (ADS)

    Lampoudis, C.; Kopecky, S.; Bouland, O.; Gunsing, F.; Noguere, G.; Plompen, A. J. M.; Sage, C.; Schillebeeckx, P.; Wynants, R.

    2013-08-01

    Resonance parameters for neutron-induced reactions on 241Am below 110 eV have been determined. The parameters result from a resonance shape analysis of transmission and capture data measured at the time-of-flight facility GELINA, with the accelerator operating at a 50 Hz repetition rate. The transmission experiments were carried out at a 25 m station using a Li glass scintillator. The capture experiments were performed at a 12.5 m station by applying the total energy detection principle in combination with the pulse height weighting technique using a pair of C6D6 detectors. The normalization of the capture data was determined by a combined least squares adjustment of the transmission and capture data. From the adjusted resonance parameters a capture cross section of 749 ± 35 b for a neutron energy of 0.0253 eV and an average radiation width of < ? ? > = 42.0 meV for s-wave resonances were obtained. A missing-level analysis for s-wave neutron resonances within the statistical model results in compatible values with previous estimates. The neutron widths obtained in this work are approximately 22% larger compared to other experimental data and evaluated data libraries. Also the thermal capture cross section is larger than most of the recommended values. However, the resonance parameter file presented in this work is consistent with results of both integral experiments and of the experimentally determined resonance integrals.

  12. Irradiation facility for boron neutron capture therapy application based on a rf-driven DT neutron source and a new beam shaping assembly (abstract)

    Microsoft Academic Search

    N. Cerullo; J. Esposito; K. N. Leung

    2002-01-01

    Selecting the best neutron source for boron neutron capture therapy (BNCT) requires optimizing neutron beam parameters. This involves solving many complex problems. Safety issues related to the use of nuclear reactor in hospital environments, as well as lower costs have led to interest in the development of accelerator-driven neutron sources. The BNCT research programs at the Nuclear Departments of Pisa

  13. Chandra Captures Neutron Star Action - Duration: 61 seconds.

    NASA Video Gallery

    This movie from NASA's Chandra X-ray Observatory shows a fast moving jet of particles produced by a rapidly rotating neutron star, and may provide new insight into the nature of some of the densest...

  14. Characterisation of neutron and gamma-ray emission from thick target Be(p,n) reaction for boron neutron capture therapy

    Microsoft Academic Search

    J. Guzek; W. R. McMurray; T. Mateva; C. B. Franklyn; U. A. S. Tapper

    1998-01-01

    Low energy accelerator-based neutron sources have promising potential for use in a clinical treatment of cancer with boron neutron capture therapy (BNCT) and boron neutron capture synovectomy (BNCS). Such sources often utilise a thick target Be(p,n) reaction using incident proton energies from several hundred keV to 1-2MeV above the reaction threshold of 2.06MeV. The resulting neutron and gamma-ray beams require

  15. Characterisation of neutron and gamma-ray emission from thick target Be(p,n) reaction for boron neutron capture therapy

    Microsoft Academic Search

    J Guzek; W. R McMurray; T Mateva; C. B Franklyn; U. A. S Tapper

    1998-01-01

    Low energy accelerator-based neutron sources have promising potential for use in a clinical treatment of cancer with boron neutron capture therapy (BNCT) and boron neutron capture synovectomy (BNCS). Such sources often utilise a thick target Be(p,n) reaction using incident proton energies from several hundred keV to 1–2 MeV above the reaction threshold of 2.06 MeV. The resulting neutron and gamma-ray

  16. IMPROVED COMPUTATIONAL CHARACTERIZATION OF THE THERMAL NEUTRON SOURCE FOR NEUTRON CAPTURE THERAPY RESEARCH AT THE UNIVERSITY OF MISSOURI

    SciTech Connect

    Stuart R. Slattery; David W. Nigg; John D. Brockman; M. Frederick Hawthorne

    2010-05-01

    Parameter studies, design calculations and initial neutronic performance measurements have been completed for a new thermal neutron beamline to be used for neutron capture therapy cell and small-animal radiobiology studies at the University of Missouri Research Reactor. The beamline features the use of single-crystal silicon and bismuth sections for neutron filtering and for reduction of incident gamma radiation. The computational models used for the final beam design and performance evaluation are based on coupled discrete-ordinates and Monte Carlo techniques that permit detailed modeling of the neutron transmission properties of the filtering crystals with very few approximations. This is essential for detailed dosimetric studies required for the anticipated research program.

  17. Measurement of the neutron capture cross section of {sup 236}U

    SciTech Connect

    Gunsing, F.; Andriamonje, S.; Berthoumieux, E.; Borella, A.; Dridi, W.; Aerts, G.; Pancin, J.; Perrot, L.; Plukis, A. [CEA/Saclay, DSM/DAPNIA, Gif-sur-Yvette (France); Schillebeeckx, P.; Wynants, R.; Plompen, A.; Rullhusen, P. [CEC-JRC-IRMM, Geel (Belgium); Furman, W. [Joint Inst. for Nuclear Research, Frank Laboratory of Neutron Physics, Dabna (Russian Federation); Goverdovski, A. [Inst. of Physics and Power Engineering, Kaluga region, Obninsk (Russian Federation); Lampoudis, C.; Koehler, P. [Oak Ridge National Laboratory, Physics Div., Oak Ridge (United States); Alvarez, H.; Duran, I.; Paradela, C. [Universidade de Santiago de Compostela (Spain); Abbondanno, U.; Fujii, K.; Milazzo, P. M.; Moreau, C. [Istituto Nazionale di Fisica Nudeare, Trieste (Italy); Alvarez-Velarde, F.; Cano-Ott, D.; Embid-Segura, M.; Gonzalez-Romero, E.; Guerrero, C.; Villamarin, D.; Vincente, M. C. [Centro de Investigaciones Energeticas Medioambientales y Technologicas, Madrid (Spain); Andrzejewski, J.; Marganiec, J. [Univ. of Lodz, Lodz (Poland); Assimakopoulos, P.; Karadimos, D.; Karamanis, D.; Papachristodoulou, C.; Patronis, N. [Univ. of Ioannina (Greece); and others

    2006-07-01

    In this paper we describe the {sup 236}U(n, {gamma}) reaction cross section measurement at the GELINA white pulsed neutron source of the Inst. for Reference Materials and Measurements (IRMM) in Geel. The sample was placed in the neutron beam at a flight station located at a nominal distance of 30 m from the neutron source. Neutron capture gamma rays were detected by two C{sub 6}D6-based liquid scintillator gamma-ray detectors as a function of the neutron time-of-flight using the pulse height weighting technique. The pulse height weighting function has been derived from Monte Carlo simulations of the detector response to mono-energetic gamma rays. The shape of the neutron flux was measured with a {sup 10}B chamber, placed about 60 cm upstream in the neutron beam. The capture yield in the resolved resonance region up to 3 keV has been derived and will be presented here. The analysis of the capture yield in terms of R-matrix resonance parameters is planned for the near future. (authors)

  18. Dose point kernel for boron-11 decay and the cellular S values in boron neutron capture therapy.

    PubMed

    Ma, Yunzhi; Geng, JinPeng; Gao, Song; Bao, Shanglian

    2006-12-01

    The study of the radiobiology of boron neutron capture therapy is based on the cellular level dosimetry of boron-10's thermal neutron capture reaction 10B(n,alpha)7Li, in which one 1.47 MeV helium-4 ion and one 0.84 MeV lithium-7 ion are spawned. Because of the chemical preference of boron-10 carrier molecules, the dose is heterogeneously distributed in cells. In the present work, the (scaled) dose point kernel of boron-11 decay, called 11B-DPK, was calculated by GEANT4 Monte Carlo simulation code. The DPK curve drops suddenly at the radius of 4.26 microm, the continuous slowing down approximation (CSDA) range of a lithium-7 ion. Then, after a slight ascending, the curve decreases to near zero when the radius goes beyond 8.20 microm, which is the CSDA range of a 1.47 MeV helium-4 ion. With the DPK data, S values for nuclei and cells with the boron-10 on the cell surface are calculated for different combinations of cell and nucleus sizes. The S value for a cell radius of 10 microm and a nucleus radius of 5 microm is slightly larger than the value published by Tung et al. [Appl. Radiat. Isot. 61, 739-743 (2004)]. This result is potentially more accurate than the published value since it includes the contribution of a lithium-7 ion as well as the alpha particle. PMID:17278826

  19. Using the TREAT reactor in support of boron neutron capture therapy (BNCT) experiments: A feasibility analysis

    SciTech Connect

    Grasseschi, G.L.; Schaefer, R.W.

    1996-03-01

    The technical feasibility of using the TREAT reactor facility for boron neutron capture therapy (BNCT) research was assessed. Using one-dimensional neutronics calculations, it was shown that the TREAT core neutron spectrum can be filtered to reduce the undesired radiation (contamination) dose per desired neutron more effectively than can the core spectra from two prominent candidate reactors. Using two-dimensional calculations, it was demonstrated that a non-optimized filter replacing the TREAT thermal column can yield a fluence of desired-energy neutrons more than twice as large as the fluence believed to be required and, at the same time, have a contamination dose per desired neutron almost as low as that from any other candidate facility. The time, effort and cost required to adapt TREAT for a mission supporting BNCT research would be modest.

  20. Neutron capture cross sections of 194Hg and the decays of 195Hg.

    PubMed

    Dorsett, S F; Krane, K S

    2015-02-01

    The thermal cross section and resonance integral have been determined for radiative neutron capture by radioactive (194)Hg by observing the ? rays emitted in the decay of (195)Hg. Captures leading to the low-spin isomer of (195)Hg give ?=877 b and I=10,270 b, while captures leading to the high-spin isomer give ?=49 b and I=608 b. Energies and intensities of the ? rays emitted in the decays of (195)Hg produced by neutron capture have been obtained with increased precision relative to previous studies with sources produced by other reactions, leading to correspondingly improved values for ?-decay branching intensities and energy levels in (195)Au. New values for the half-lives of (195g)Hg and (195m)Hg are also reported. PMID:25479438

  1. Early clinical experience of boron neutron capture therapy for glioblastoma multiforme

    SciTech Connect

    Joel, D.D.; Bergland, R.; Capala, J. [and others

    1995-12-31

    Boron neutron capture therapy (BNCT) is a binary treatment modality that can selectively irradiate tumor tissue. BNCT uses drugs containing a stable isotope of boron. {sup 10}B, to sensitize tumor cells to irradiation by low energy (thermal) neutrons. The interaction of the {sup 10}B with a thermal neutron (neutron capture) causes the {sup 10}B nucleus to split, releasing an alpha particle and a lithium nucleus. These products of the {sup 10}B(n, {alpha}){sup 7}Li reaction are very damaging to cells but have a combined path length in tissue of approximately 14 {mu}m, or roughly the diameter of one or two cells. Thus, most of the ionizing energy imparted to tissue is localized to {sup 10}B-loaded cells.

  2. Neutron Capture on 130Sn during r-Process Freeze-Out

    SciTech Connect

    Beun, Joshua [North Carolina State University; Blackmon, Jeffery C [Louisiana State University; Hix, William Raphael [ORNL; Mclaughlin, Gail C [North Carolina State University; Smith, Michael Scott [ORNL; Surman, Rebecca [Union College

    2009-01-01

    We examine the role of neutron capture on {sup 130}Sn during r-process freeze-out in the neutrino-driven wind environment of the core-collapse supernova. We find that the global r-process abundance pattern is sensitive to the magnitude of the neutron capture cross section of {sup 130}Sn. The changes to the abundance pattern include not only a relative decrease in the abundance of {sup 130}Sn and an increase in the abundance of {sup 131}Sn, but also a shift in the distribution of material in the rare earth and third peak regions.

  3. Simultaneous Measurement of the Neutron Capture and Fission Yields of 233U

    SciTech Connect

    Berthoumieux, E. [CEA, Saclay, France; Koehler, Paul Edward [ORNL; Collaboration, n_TOF [Collaboration affiliations

    2008-01-01

    We have measured the neutron capture and fission cross section of {sup 233}U at the neutron time-of-flight facility n{_}TOF at CERN in the energy range from 1 eV to 1 MeV with high accuracy by using a high performance 4{pi} BaF{sub 2} Total Absorption Calorimeter (TAC) as a detection device. The method, based on the TAC energy response study, allowing to disentangle between {gamma}'s originating from fission and capture will be presented as well as the first very preliminary results.

  4. Measurement on the thermal neutron capture cross section of w-180

    E-print Network

    W. G. Kang; Y. D. Kim; J. I. Lee; I. S. Hahn; A. R. Kim; H. J. Kim

    2007-04-24

    We have measured the thermal neutron capture cross section for w-180 nucleus. There is only one previous data on this cross section with a value of 30 $^{+300%}_{-100%}$ barn. To consider w-181 as a low energy neutrino source, the thermal neutron capture cross section should be measured more precisely to estimate the production rate of w-181 inside a nuclear reactor. We measured the cross section of w-180 with a natural tungsten foil and obtained a new value of 21.9 $\\pm$ 2.5 barn

  5. Neutron capture on 130Sn during r-process freeze-out

    E-print Network

    J. Beun; J. C. Blackmon; W. R. Hix; G. C. McLaughlin; M. S. Smith; R. Surman

    2008-06-24

    We examine the role of neutron capture on 130Sn during r-process freeze-out in the neutrino-driven wind environment of the core-collapse supernova. We find that the global r-process abundance pattern is sensitive to the magnitude of the neutron capture cross section of 130Sn. The changes to the abundance pattern include not only a relative decrease in the abundance of 130Sn and an increase in the abundance of 131Sn, but also a shift in the distribution of material in the rare earth and third peak regions.

  6. Neutron emission following muon capture in Ce-142, Ce-140, Ba-138, and Sn-120.

    NASA Technical Reports Server (NTRS)

    Lucas, G. R., Jr.; Martin, P.; Welsh, R. E.; Jenkins, D. A.; Powers, R. J.; Kunselman, A. R.; Miller, G. H.

    1973-01-01

    Branching ratios to excited nuclear states formed after muon capture have been measured with Ge(Li) detectors. The delayed gamma rays were observed in studies of muonic Ce-142, Ce-140, Ba-138, and Sn-120, using separated isotopes. The resulting isotopes formed indicate at least a 60% probability of neutron emission upon muon capture, with the most likely product resulting from single-neutron emission. No evidence for delayed proton emission with a probability higher than 2% was found. Using our more precise energies for the observed nuclear transitions, we present revised energy levels schemes for La-141, La-139, Cs-137, and In-119.

  7. Characteristics of BGO scintillator for use in neutron capture cross section measurements

    NASA Astrophysics Data System (ADS)

    Yamamoto, Shuji; Fujita, Yoshiaki; Shibata, Toshikazu; Selvi, Saim

    1986-09-01

    A detector assembly of BGO scintillators has been set up for use in neutron capture cross section measurements as a total absorption detector of prompt capture gamma rays. This report describes a few experimental studies of the essential characteristics of the BGO detector assembly. The assembly has a scintillator volume of 1.5 l, and the response to the gamma-ray cascade of neutron capture by Au has been found to be nearly equivalent to that of a typical organic-liquid scintillator tank. The efficiency for the 478 keV gamma ray of the 10B(n, ??) reaction has been determined for the purpose of using the reaction as a neutron flux monitor impinging on a capture sample. The sensitivity to neutrons scattered with a capture sample has been measured between the thermal region and 60 keV. The sensitivity is comparatively high and the employment of a 6LiF shield has been shown to be effective for the reduction of the sensitivity in the eV region.

  8. Gadolinium neutron capture brachytherapy (GdNCB), a new treatment method for intravascular brachytherapy

    Microsoft Academic Search

    Hans Lundqvist; Per Munck af Rosenschoeld; Arash Rezaei; Shirin A. Enger

    2006-01-01

    Restenosis is a major problem after balloon angioplasty and stent implantation. The aim of this study is to introduce gadolinium neutron capture brachytherapy (GdNCB) as a suitable modality for treatment of stenosis. The utility of GdNCB in intravascular brachytherapy (IVBT) of stent stenosis is investigated by using the GEANT4 and MCNP4B Monte Carlo radiation transport codes. To study capture rate,

  9. Boronated DNA-binding compounds as potential agents for boron neutron capture therapy.

    PubMed

    Crossley, Ellen L; Ziolkowski, Erin J; Coderre, Jeffrey A; Rendina, Louis M

    2007-03-01

    Boron Neutron Capture Therapy (BNCT) is a binary cancer treatment that exploits the short range particles released from a nuclear fission reaction involving the non-radioactive 10B nucleus and low-energy (thermal) neutrons for the destruction of tumour cells. If boronated agents are targeted towards chromosomal DNA, the efficiency of BNCT is greatly enhanced. This article presents a concise review of DNA-binding compounds that have been functionalised with boron. PMID:17346220

  10. Neutron-capture experiment on 77Se with EXILL at ILL Grenoble

    NASA Astrophysics Data System (ADS)

    Lorenz, Ch.; John, R.; Massarczyk, R.; Schwengner, R.; Blanc, A.; de France, G.; Jentschel, M.; Köster, U.; Mutti, P.; Simpson, G.; Soldner, T.; Urban, W.; Valenta, S.; Belgya, T.

    2015-05-01

    The neutron capture reaction at 77Se has been studied with cold neutrons in the course of the EXILL campaign at the high-flux reactor of the Institut Laue-Langevin Grenoble. A simulation of the detector array with Geant4 has been accomplished and evaluated. The detector response has been deduced and measured spectra were unfolded, which have been compared with simulations using ?Dex to determine strength functions.

  11. Boron Neutron Capture Therapy of Cancer: Current Status and Future Prospects

    Microsoft Academic Search

    Rolf F. Barth; Jeffrey A. Coderre; M. GraaH

    2005-01-01

    Background: Boron neutron capture therapy (BNCT) isbased on the nuclear reaction that occurswhen boron-10 isirradiated with low-energy thermal neutronsto yield high linear energy transferA particles and recoiling lithium-7 nuclei. Clinical interest in BNCT hasfocused primarily on the treatment of high-grade gliomas and either cutaneous primaries or cerebral metastases of mel- anoma, most recently, head and neck and liver cancer. Neutron

  12. The n_TOF Total Absorption Calorimeter for neutron capture measurements at CERN

    SciTech Connect

    Guerrero, C. [Centro de Investigaciones Energeticas Medioambientales y Technol., Madrid, Spain; Koehler, Paul Edward [ORNL

    2009-01-01

    The n{_}TOF Collaboration has built and commissioned a high-performance detector for (n,{gamma}) measurements called the Total Absorption Calorimeter (TAC). The TAC was especially designed for measuring neutron capture cross-sections of low-mass and/or radioactive samples with the accuracy required for nuclear technology and stellar nucleosynthesis. We present a detailed description of the TAC and discuss its overall performance in terms of energy and time resolution, background discrimination, detection efficiency and neutron sensitivity.

  13. Stellar neutron capture cross sections of Nd, Pm, and Sm isotopes

    Microsoft Academic Search

    K. A. Toukan; K. Debus; F. Kaeppeler; G. Reffo

    1995-01-01

    The neutron capture cross sections of 146,148,150Nd have been determined relative to that of gold by means of the activation method. The samples were irradiated in a quasistellar neutron spectrum for kT=25 keV using the 7Li(p,n)7Be reaction near threshold. Variation of the experimental conditions in different activations and the use of different samples allowed for the reliable determination of corrections

  14. Neutron Capture Cross Sections of ^234U and ^151Sm Measured at LANSCE.

    NASA Astrophysics Data System (ADS)

    Rundberg, R. S.; Wilhelmy, J. B.; Miller, G. G.; Dry, D.; Palmer, P.; Fowler, M. M.; Ullmann, J. L.; Haight, R. C.; Hunt, L.

    2002-04-01

    The neutron capture cross section of radioactive and rare stable isotopes are needed both for the improved interpretation of historical nuclear weapons test data and the interpretation of isotopic distributions from s-process and r-process nucleosynthesis. ^151Sm is an important s-process branch point. Accurate cross sections in the energy range from 1 keV to 100 keV are needed to model the production of ^151Eu and ^153Eu by ^13C(?, n)^16O neutrons (8 keV) and ^22Ne(?, n) ^25Mg neutrons (30 keV) in asymptotic giant branch, AGB, stars. The 90 y beta decay halflife makes the ^151Eu abundance sensitive to ^22Ne burning that is believed to occur during episodes of convection lasting about 100 years. The neutron capture cross section of ^151Sm, and ^234U were measured by neutron time-of-flight on the newly constructed flight path 14 at the Lujan Center of the Los Alamos Neutron Science Center, LANSCE. The excitation functions were determined over the energy range from 1.0 eV up to 100 keV. Capture gamma rays were detected using a pair of deuterated benzene scintillators. The pulse height weighting method was applied. The results of these measurements will be presented.

  15. A pilot study of an epithermal neutron source based on a low-energy proton accelerator for boron neutron-capture therapy

    Microsoft Academic Search

    Changkwang Chris

    1989-01-01

    In this study, a hospital-based low-energy proton accelerator neutron irradiation facility (LPANIF) for boron neutron capture therapy (BNCT) is described. Neutrons are generated by 2.5 MeV protons impinging upon a lithium-7 target. The neutrons emitted from the lithium target are too energetic for BNCT, and must be moderated. A moderator assembly served this purpose. The neutron field generated by the

  16. Gadolinium neutron capture brachytherapy (GdNCB), a new treatment method for intravascular brachytherapy

    SciTech Connect

    Enger, Shirin A.; Rezaei, Arash; Munck af Rosenschoeld, Per; Lundqvist, Hans [Division of Biomedical Radiation Sciences, Department of Oncology, Radiology and Clinical Immunology, Rudbeck Laboratory, Uppsala University, SE-751 85 Uppsala (Sweden); Division of Medical Radiation Physics, Department of Oncology-Pathology, Karolinska Institutet, SE-171 76 Stockholm (Sweden) and Studsvik Medical AB, SE-612 82 Nykoeping (Sweden); Department of Radiation Physics, Lund University Hospital, SE-22185 Lund (Sweden); Division of Biomedical Radiation Sciences, Department of Oncology, Radiology and Clinical Immunology, Rudbeck Laboratory, Uppsala University, SE-751 85 Uppsala (Sweden)

    2006-01-15

    Restenosis is a major problem after balloon angioplasty and stent implantation. The aim of this study is to introduce gadolinium neutron capture brachytherapy (GdNCB) as a suitable modality for treatment of stenosis. The utility of GdNCB in intravascular brachytherapy (IVBT) of stent stenosis is investigated by using the GEANT4 and MCNP4B Monte Carlo radiation transport codes. To study capture rate, Kerma, absorbed dose and absorbed dose rate around a Gd-containing stent activated with neutrons, a 30 mm long, 5 mm diameter gadolinium foil is chosen. The input data is a neutron spectrum used for clinical neutron capture therapy in Studsvik, Sweden. Thermal neutron capture in gadolinium yields a spectrum of high-energy gamma photons, which due to the build-up effect gives an almost flat dose delivery pattern to the first 4 mm around the stent. The absorbed dose rate is 1.33 Gy/min, 0.25 mm from the stent surface while the dose to normal tissue is in order of 0.22 Gy/min, i.e., a factor of 6 lower. To spare normal tissue further fractionation of the dose is also possible. The capture rate is relatively high at both ends of the foil. The dose distribution from gamma and charge particle radiation at the edges and inside the stent contributes to a nonuniform dose distribution. This will lead to higher doses to the surrounding tissue and may prevent stent edge and in-stent restenosis. The position of the stent can be verified and corrected by the treatment plan prior to activation. Activation of the stent by an external neutron field can be performed days after catherization when the target cells start to proliferate and can be expected to be more radiation sensitive. Another advantage of the nonradioactive gadolinium stent is the possibility to avoid radiation hazard to personnel.

  17. Gadolinium neutron capture brachytherapy (GdNCB), a new treatment method for intravascular brachytherapy.

    PubMed

    Enger, Shirin A; Rezaei, Arash; Munck af Rosenschöld, Per; Lundqvist, Hans

    2006-01-01

    Restenosis is a major problem after balloon angioplasty and stent implantation. The aim of this study is to introduce gadolinium neutron capture brachytherapy (GdNCB) as a suitable modality for treatment of stenosis. The utility of GdNCB in intravascular brachytherapy (IVBT) of stent stenosis is investigated by using the GEANT4 and MCNP4B Monte Carlo radiation transport codes. To study capture rate, Kerma, absorbed dose and absorbed dose rate around a Gd-containing stent activated with neutrons, a 30 mm long, 5 mm diameter gadolinium foil is chosen. The input data is a neutron spectrum used for clinical neutron capture therapy in Studsvik, Sweden. Thermal neutron capture in gadolinium yields a spectrum of high-energy gamma photons, which due to the build-up effect gives an almost flat dose delivery pattern to the first 4 mm around the stent. The absorbed dose rate is 1.33 Gy/min, 0.25 mm from the stent surface while the dose to normal tissue is in order of 0.22 Gy/min, i.e., a factor of 6 lower. To spare normal tissue further fractionation of the dose is also possible. The capture rate is relatively high at both ends of the foil. The dose distribution from gamma and charge particle radiation at the edges and inside the stent contributes to a nonuniform dose distribution. This will lead to higher doses to the surrounding tissue and may prevent stent edge and in-stent restenosis. The position of the stent can be verified and corrected by the treatment plan prior to activation. Activation of the stent by an external neutron field can be performed days after catherization when the target cells start to proliferate and can be expected to be more radiation sensitive. Another advantage of the nonradioactive gadolinium stent is the possibility to avoid radiation hazard to personnel. PMID:16485408

  18. OPTIMIZATION OF THE EPITHERMAL NEUTRON BEAM FOR BORON NEUTRON CAPTURE THERAPY AT THE BROOKHAVEN MEDICAL RESEARCH REACTOR.

    SciTech Connect

    HU,J.P.; RORER,D.C.; RECINIELLO,R.N.; HOLDEN,N.E.

    2002-08-18

    Clinical trials of Boron Neutron Capture Therapy for patients with malignant brain tumor had been carried out for half a decade, using an epithermal neutron beam at the Brookhaven's Medical Reactor. The decision to permanently close this reactor in 2000 cut short the efforts to implement a new conceptual design to optimize this beam in preparation for use with possible new protocols. Details of the conceptual design to produce a higher intensity, more forward-directed neutron beam with less contamination from gamma rays, fast and thermal neutrons are presented here for their potential applicability to other reactor facilities. Monte Carlo calculations were used to predict the flux and absorbed dose produced by the proposed design. The results were benchmarked by the dose rate and flux measurements taken at the facility then in use.

  19. Neutron Capture Measurements on Tl-isotopes at DANCE

    Microsoft Academic Search

    A. Couture; T. A. Bredeweg; E.-I. Esch; M. Jandel; R. C. Haight; J. M. O'Donnell; R. Reifarth; R. S. Rundberg; J. L. Ullmann; D. J. Vieira; J. M. Wouters

    2006-01-01

    The thallium isotopes play an important role in the s-process nucleosynthesis at the s-process endpoint. Furthermore, ^204Tl is one of few branch point isotopes in the endpoint region. The understanding of branch point isotopes provides modeling constraints on the temperatures during which the process takes place. The production of s-only ^204Pb is controlled entirely by ^204Tl. Measurements of the capture

  20. Monte Carlo calculations of lung dose in ORNL phantom for boron neutron capture therapy.

    PubMed

    Krstic, D; Markovic, V M; Jovanovic, Z; Milenkovic, B; Nikezic, D; Atanackovic, J

    2014-10-01

    Monte Carlo simulations were performed to evaluate dose for possible treatment of cancers by boron neutron capture therapy (BNCT). The computational model of male Oak Ridge National Laboratory (ORNL) phantom was used to simulate tumours in the lung. Calculations have been performed by means of the MCNP5/X code. In this simulation, two opposite neutron beams were considered, in order to obtain uniform neutron flux distribution inside the lung. The obtained results indicate that the lung cancer could be treated by BNCT under the assumptions of calculations. PMID:24435912

  1. Stellar nucleosynthesis and the 24keV neutron capture cross sections of some heavy nuclei

    Microsoft Academic Search

    T. Bradley; Z. Parsa; M. L. Stelts; R. E. Chrien

    1979-01-01

    The neutron capture cross sections of ¹¹²Sn, ¹³°Ba, ¹⁴⁶Nd, ¹⁴⁸Nd, ¹⁸⁶W, ¹⁹°Os, and ¹⁹²Os at 24 keV neutron energy were measured with respect to ¹⁹⁷Au by activation in a 24 keV neutron beam at the Brookhaven High Flux Beam Reactor. The reliability of this technique was verified by remeasuring the cross section of ¹⁸⁶W and comparing it to previous measurements.

  2. Population of low-spin levels in ^75,77Ge in neutron-capture reactions

    NASA Astrophysics Data System (ADS)

    Sharp, N. E.; Cummings, B. J.; Chiara, C. J.; Walters, W. B.; Bindel, R. T.; Paul, R. L.

    2010-02-01

    The structure of nuclei near ^76Ge has been of interest owing to the possibility of neutrinoless double beta decay. To further characterize the low-energy, low-spin structure for ^75Ge and ^77Ge, we have studied the gamma rays following neutron capture on highly enriched ^74Ge and ^76Ge, respectively, in experiments performed at the cold-neutron beam line at the NIST Center for Neutron Research. The new spectra will be shown and insight into the level structures presented. )

  3. On the capture of dark matter by neutron stars

    NASA Astrophysics Data System (ADS)

    Güver, Tolga; Emre Erkoca, Arif; Hall Reno, Mary; Sarcevic, Ina

    2014-05-01

    We calculate the number of dark matter particles that a neutron star accumulates over its lifetime as it rotates around the center of a galaxy, when the dark matter particle is a self-interacting boson but does not self-annihilate. We take into account dark matter interactions with baryonic matter and the time evolution of the dark matter sphere as it collapses within the neutron star. We show that dark matter self-interactions play an important role in the rapid accumulation of dark matter in the core of the neutron star. We consider the possibility of determining an exclusion region of the parameter space for dark matter mass and dark matter interaction cross section with the nucleons as well as dark matter self-interaction cross section, based on the observation of old neutron stars. We show that for a dark matter density of 103 GeV/cm3and dark matter mass m? lesssim 10 GeV, there is a potential exclusion region for dark matter interactions with nucleons that is three orders of magnitude more stringent than without self-interactions. The potential exclusion region for dark matter self-interaction cross sections is many orders of magnitude stronger than the current Bullet Cluster limit. For example, for high dark matter density regions, we find that for m? ~ 10 GeV when the dark matter interaction cross section with the nucleons ranges from ??n ~ 10-52 cm2 to ??n ~ 10-57 cm2, the dark matter self-interaction cross section limit is ??? lesssim 10-33 cm2, which is about ten orders of magnitude stronger than the Bullet Cluster limit.

  4. Independent measurement of the neutrino mixing angle ?13 via neutron capture on hydrogen at Daya Bay

    DOE PAGESBeta

    Jaffe D. E.; Jaffe, D.E., et al. Daya Bay Collaboration

    2014-10-01

    A new measurement of the ?13 mixing angle has been obtained at the Daya Bay Reactor Neutrino Experiment via the detection of inverse beta decays tagged by neutron capture on hydrogen. The antineutrino events for hydrogen capture are distinct from those for gadolinium capture with largely different systematic uncertainties, allowing a determination independent of the gadolinium-capture result and an improvement on the precision of the ?13 measurement. With a 217-day antineutrino data set obtained with six antineutrino detectors and from six 2.9 GWth reactors, the rate deficit observed at the far hall is interpreted as sin22?13=0.083±0.018 in the three-flavor oscillation model. When combined with the gadolinium-capture result from Daya Bay, we obtain sin22?13=0.089±0.008 as the final result for the six-antineutrino-detector configuration of the Daya Bay experiment.

  5. Independent measurement of the neutrino mixing angle ?13 via neutron capture on hydrogen at Daya Bay

    DOE PAGESBeta

    Jaffe D. E.; Jaffe, D.E., et al. Daya Bay Collaboration

    2014-10-01

    A new measurement of the ?13 mixing angle has been obtained at the Daya Bay Reactor Neutrino Experiment via the detection of inverse beta decays tagged by neutron capture on hydrogen. The antineutrino events for hydrogen capture are distinct from those for gadolinium capture with largely different systematic uncertainties, allowing a determination independent of the gadolinium-capture result and an improvement on the precision of the ?13 measurement. With a 217-day antineutrino data set obtained with six antineutrino detectors and from six 2.9 GWth reactors, the rate deficit observed at the far hall is interpreted as sin22?13=0.083±0.018 in the three-flavor oscillationmore »model. When combined with the gadolinium-capture result from Daya Bay, we obtain sin22?13=0.089±0.008 as the final result for the six-antineutrino-detector configuration of the Daya Bay experiment.« less

  6. Neutron capture therapy with a new boron-porphyrin compound in the rat 9L glioma model.

    PubMed

    Shibata, Y; Matsumura, A; Yamamoto, T; Nakagawa, K; Yoshii, Y; Nose, T; Sakata, I; Nakajima, S; Hayakawa, Y; Ono, K

    1998-09-01

    Neutron capture therapy with a new boron-porphyrin compound was tested in a rat brain tumor model. Although the concentration of boron in the tumor was too low to elicit a therapeutic effect, prominent histopathologic changes, such as necrosis, congestion and bleeding were observed in the tumors of the rats which were administered the boron neutron capture therapy. PMID:9894763

  7. Boron neutron capture therapy of malignant brain tumors at the Brookhaven Medical Research Reactor

    SciTech Connect

    Joel, D.D.; Coderre, J.A.; Chanana, A.D. [Brookhaven National Lab., Upton, NY (United States). Medical Dept.

    1996-12-31

    Boron neutron capture therapy (BNCT) is a bimodal form of radiation therapy for cancer. The first component of this treatment is the preferential localization of the stable isotope {sup 10}B in tumor cells by targeting with boronated compounds. The tumor and surrounding tissue is then irradiated with a neutron beam resulting in thermal neutron/{sup 10}B reactions ({sup 10}B(n,{alpha}){sup 7}Li) resulting in the production of localized high LET radiation from alpha and {sup 7}Li particles. These products of the neutron capture reaction are very damaging to cells, but of short range so that the majority of the ionizing energy released is microscopically confined to the vicinity of the boron-containing compound. In principal it should be possible with BNCT to selectively destroy small nests or even single cancer cells located within normal tissue. It follows that the major improvements in this form of radiation therapy are going to come largely from the development of boron compounds with greater tumor selectivity, although there will certainly be advances made in neutron beam quality as well as the possible development of alternative sources of neutron beams, particularly accelerator-based epithermal neutron beams.

  8. Estimates for Pu-239 loadings in burial ground culverts based on fast/slow neutron measurements

    SciTech Connect

    Winn, W.G.; Hochel, R.C.; Hofstetter, K.J.; Sigg, R.A.

    1989-08-15

    This report provides guideline estimates for Pu-239 mass loadings in selected burial ground culverts. The relatively high recorded Pu-239 contents of these culverts have been appraised as suspect relative to criticality concerns, because they were assayed only with the solid waste monitor (SWM) per gamma-ray counting. After 1985, subsequent waste was also assayed with the neutron coincidence counter (NCC), and a comparison of the assay methods showed that the NCC generally yielded higher assays than the SWM. These higher NCC readings signaled a need to conduct non-destructive/non-intrusive nuclear interrogations of these culverts, and a technical team conducted scoping measurements to illustrate potential assay methods based on neutron and/or gamma counting. A fast/slow neutron method has been developed to estimate the Pu-239 in the culverts. In addition, loading records include the SWM assays of all Pu-239 cuts of some of the culvert drums and these data are useful in estimating the corresponding NCC drum assays from NCC vs SWM data. Together, these methods yield predictions based on direct measurements and statistical inference.

  9. Boron microlocalization in oral mucosal tissue: implications for boron neutron capture therapy

    Microsoft Academic Search

    G M Morris; D R Smith; H Patel; S Chandra; G H Morrison; J W Hopewell; M Rezvani; P L Micca; J A Coderre

    2000-01-01

    Clinical studies of the treatment of glioma and cutaneous melanoma using boron neutron capture therapy (BNCT) are currently taking place in the USA, Europe and Japan. New BNCT clinical facilities are under construction in Finland, Sweden, England and California. The observation of transient acute effects in the oral mucosa of a number of glioma patients involved in the American clinical

  10. The Accuracy of Pulsed Neutron Capture Logs for Residual Oil Saturation

    Microsoft Academic Search

    Phillip Schenewerk; Roy Knapp; Walter Fertl

    1982-01-01

    Pulsed neutron capture (PNC) logs have been used to determine residual oil saturations for many years. A previous study found that at low values of residual oil saturation (ROS) conventional PNC logging techniques did not have the accuracy necessary for enhanced oil recovery decision making requirements. Special log-inject-log techniques were developed in order to reduce the uncertainty in values of

  11. Rat Brain Tumor Models to Assess the Efficacy of Boron Neutron Capture Therapy: A Critical Evaluation

    Microsoft Academic Search

    Rolf F. Barth; Weilian Yang; Jeffrey A. Coderre

    2003-01-01

    Development of any therapeutic modality can be facilitated by the use of the appropriate animal models to assess its efficacy. This report primarily will focus on our studies using the F98 and 9L rat glioma models to evaluate the effectiveness of boron neutron capture therapy (BNCT) of brain tumors. Following intracerebral implantation the biological behavior of each tumor resembles that

  12. A Preliminary Experimental Study of Boron Neutron Capture Therapy for Malignant Tumors Spreading in Thoracic Cavity

    Microsoft Academic Search

    Minoru Suzuki; Yoshinori Sakurai; Shinichiro Masunaga; Yuko Kinashi; Kenji Nagata; Akira Maruhashi; Koji Ono

    Background: The purpose of the present study is to verify the treatment effects of boron neutron capture therapy (BNCT) in ectopic tumors implanted in the thoracic cavity mimicking malignant pleural mesothelioma (MPM). Methods: The tumor model was created by implanting murine squamous cell carcinoma cells into the thoracic cavity. Mice were sorted into four groups: group I for non-treatment; group

  13. One- and two-neutron capture reactions of light nuclei in nuclear astrophysics

    E-print Network

    H. Herndl; R. Hofinger; H. Oberhummer

    1998-03-04

    We discuss models to calculate one- and two-neutron capture reactions on light nuclei. These are applied to calculate the reaction rates of 15N(n,gamma)16N, 16N(n,gamma)17}N and 4He(2n,gamma)6He. The possible astrophysical importance is discussed.

  14. Quantitative interpretation of pulsed neutron capture logs: Part 1 --Fast numerical simulation

    E-print Network

    Torres-Verdín, Carlos

    Jordan G. Mimoun1 , Carlos Torres-Verdi´n2 , and William E. Preeg3 ABSTRACT Pulsed neutron capture (PNC received much attention (Clavier et al., 1971b; Nutt and Watfa, 1989; Kimminau and Plasek, 1992; Cowan and Menke, 2010), as well as non-Archie formations (e.g., carbo- nates and shaly sands), may limit

  15. Experimental Transport Benchmarks for Physical Dosimetry to Support Development of Fast-Neutron Therapy with Neutron Capture Augmentation

    SciTech Connect

    D. W. Nigg; J. K. Hartwell; J. R. Venhuizen; C. A. Wemple; R. Risler; G. E. Laramore; W. Sauerwein; G. Hudepohl; A. Lennox

    2006-06-01

    The Idaho National Laboratory (INL), the University of Washington (UW) Neutron Therapy Center, the University of Essen (Germany) Neutron Therapy Clinic, and the Northern Illinois University(NIU) Institute for Neutron Therapy at Fermilab have been collaborating in the development of fast-neutron therapy (FNT) with concurrent neutron capture (NCT) augmentation [1,2]. As part of this effort, we have conducted measurements to produce suitable benchmark data as an aid in validation of advanced three-dimensional treatment planning methodologies required for successful administration of FNT/NCT. Free-beam spectral measurements as well as phantom measurements with Lucite{trademark} cylinders using thermal, resonance, and threshold activation foil techniques have now been completed at all three clinical accelerator facilities. The same protocol was used for all measurements to facilitate intercomparison of data. The results will be useful for further detailed characterization of the neutron beams of interest as well as for validation of various charged particle and neutron transport codes and methodologies for FNT/NCT computational dosimetry, such as MCNP [3], LAHET [4], and MINERVA [5].

  16. Characteristics comparison between a cyclotron-based neutron source and KUR-HWNIF for boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Tanaka, H.; Sakurai, Y.; Suzuki, M.; Masunaga, S.; Kinashi, Y.; Kashino, G.; Liu, Y.; Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Maruhashi, A.; Ono, K.

    2009-06-01

    At Kyoto University Research Reactor Institute (KURRI), 275 clinical trials of boron neutron capture therapy (BNCT) have been performed as of March 2006, and the effectiveness of BNCT has been revealed. In order to further develop BNCT, it is desirable to supply accelerator-based epithermal-neutron sources that can be installed near the hospital. We proposed the method of filtering and moderating fast neutrons, which are emitted from the reaction between a beryllium target and 30-MeV protons accelerated by a cyclotron accelerator, using an optimum moderator system composed of iron, lead, aluminum and calcium fluoride. At present, an epithermal-neutron source is under construction from June 2008. This system consists of a cyclotron accelerator, beam transport system, neutron-yielding target, filter, moderator and irradiation bed. In this article, an overview of this system and the properties of the treatment neutron beam optimized by the MCNPX Monte Carlo neutron transport code are presented. The distribution of biological effect weighted dose in a head phantom compared with that of Kyoto University Research Reactor (KUR) is shown. It is confirmed that for the accelerator, the biological effect weighted dose for a deeply situated tumor in the phantom is 18% larger than that for KUR, when the limit dose of the normal brain is 10 Gy-eq. The therapeutic time of the cyclotron-based neutron sources are nearly one-quarter of that of KUR. The cyclotron-based epithermal-neutron source is a promising alternative to reactor-based neutron sources for treatments by BNCT.

  17. Thermal-neutron capture by {sup 58}Ni, {sup 59}Ni, and {sup 60}Ni

    SciTech Connect

    Raman, S.; Ouyang Xiaoping; Islam, M.A.; Starner, J.W.; Jurney, E.T.; Lynn, J.E.; Martinez-Pinedo, G. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); ICREA and Institut d'Estudis Espacials de Catalunya, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain)

    2004-10-01

    We have studied the primary and secondary {gamma} rays (414 in {sup 59}Ni, 390 in {sup 60}Ni, and 240 in {sup 61}Ni) following thermal-neutron capture by the stable {sup 58}Ni, radioactive {sup 59}Ni, and stable {sup 60}Ni isotopes. Most of these {gamma} rays have been incorporated into the corresponding level schemes consisting of 65 levels in {sup 59}Ni, 88 levels in {sup 60}Ni, and 40 levels in {sup 61}Ni. The measured neutron separation energies (S{sub n} in keV) for {sup 59}Ni, {sup 60}Ni, and {sup 61}Ni are, respectively, 8999.28{+-}0.05, 11 387.73{+-}0.05, and 7820.11{+-}0.05. The measured thermal-neutron capture cross sections (in barns) for {sup 58}Ni, {sup 59}Ni, and {sup 60}Ni are, respectively, 4.13{+-}0.05, 73.7{+-}1.8, and 2.34{+-}0.05. In all three cases, primary electric-dipole (E1) transitions account for the bulk of the total capture cross section. We have calculated these E1 partial cross sections (in {sup 59}Ni and {sup 61}Ni) using direct-capture theory and models of compound-nuclear capture. The agreement between theory and experiment is good. The experimental level schemes have been compared with the results from a large-basis shell-model calculation. The agreement was also found to be quite good.

  18. Neutron-capture Cross Sections from Indirect Measurements

    SciTech Connect

    Escher, J E; Burke, J T; Dietrich, F S; Ressler, J J; Scielzo, N D; Thompson, I J

    2011-10-18

    Cross sections for compound-nuclear reactions play an important role in models of astrophysical environments and simulations of the nuclear fuel cycle. Providing reliable cross section data remains a formidable task, and direct measurements have to be complemented by theoretical predictions and indirect methods. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f) reactions, but need to be improved upon for applications to capture reactions.

  19. Design of neutron beams at the Argonne Continuous Wave Linac (ACWL) for boron neutron capture therapy and neutron radiography

    SciTech Connect

    Zhou, X.L. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Nuclear Engineering; McMichael, G.E. [Argonne National Lab., Idaho Falls, ID (United States). Technology Development Div.

    1994-10-01

    Neutron beams are designed for capture therapy based on p-Li and p-Sc reactions using the Argonne Continuous Wave Linac (ACWL). The p-Li beam will provide a 2.5 {times} 10{sup 9} n/cm{sup 2}s epithermal flux with 7 {times} 10{sup 5} {gamma}/cm{sup 2}s contamination. On a human brain phantom, this beam allows an advantage depth (AD) of 10 cm, an advantage depth dose rate (ADDR) of 78 cGy/min and an advantage ratio (AR) of 3.2. The p-Sc beam offers 5.9 {times} 10{sup 7} n/cm{sup 2}s and a dose performance of AD = 8 cm and AR = 3.5, suggesting the potential of near-threshold (p,n) reactions such as the p-Li reaction at E{sub p} = 1.92 MeV. A thermal radiography beam could also be obtained from ACWL.

  20. THORIE DE LA CAPTURE SLECTIVE DES NEUTRONS LENTS PAR CERTAINS NOYAUX Par FRANCIS PETRIN et WALTER M. ELSASSER.

    E-print Network

    Boyer, Edmond

    THÉORIE DE LA CAPTURE SÉLECTIVE DES NEUTRONS LENTS PAR CERTAINS NOYAUX Par FRANCIS PETRIN et WALTER neutrons lents observées pour quelques éléments par Fermi (plus de mille fois la section nucléaire), sans supposer d'action à distance entre les neutrons et les noyaux (1). Pour une interaction limitée au domaine

  1. Optimization study for an epithermal neutron beam for boron neutron capture therapy at the University of Virginia Research Reactor

    SciTech Connect

    Burns, T.D. Jr.

    1995-05-01

    The non-surgical brain cancer treatment modality, Boron Neutron Capture Therapy (BNCT), requires the use of an epithermal neutron beam. This purpose of this thesis was to design an epithermal neutron beam at the University of Virginia Research Reactor (UVAR) suitable for BNCT applications. A suitable epithermal neutron beam for BNCT must have minimal fast neutron and gamma radiation contamination, and yet retain an appreciable intensity. The low power of the UVAR core makes reaching a balance between beam quality and intensity a very challenging design endeavor. The MCNP monte carlo neutron transport code was used to develop an equivalent core radiation source, and to perform the subsequent neutron transport calculations necessary for beam model analysis and development. The code accuracy was validated by benchmarking output against experimental criticality measurements. An epithermal beam was designed for the UVAR, with performance characteristics comparable to beams at facilities with cores of higher power. The epithermal neutron intensity of this beam is 2.2 {times} 10{sup 8} n/cm{sup 2} {center_dot} s. The fast neutron and gamma radiation KERMA factors are 10 {times} 10{sup {minus}11}cGy{center_dot}cm{sup 2}/n{sub epi} and 20 {times} 10{sup {minus}11} cGy{center_dot}cm{sup 2}/n{sub epi}, respectively, and the current-to-flux ratio is 0.85. This thesis has shown that the UVAR has the capability to provide BNCT treatments, however the performance characteristics of the final beam of this study were limited by the low core power.

  2. NIFTI and DISCOS: New concepts for a compact accelerator neutron source for boron neutron capture therapy applications

    SciTech Connect

    Powell, J.; Ludewig, H.; Todosow, M.; Reich, M. [Brookhaven National Lab., Upton, NY (United States). Dept. of Advanced Technology

    1995-06-01

    Two new concepts, NIFTI and DISCOS, are described. These concepts enable the efficient production of epithermal neutrons for BNCT (Boron Neutron Capture Therapy) medical treatment, utilizing a low current, low energy proton beam impacting on a lithium target. The NIFTI concept uses fluoride compounds, such as lead or beryllium fluoride, to efficiently degrade high energy neutrons from the lithium target to the lower energies required for BNCT. The fluoride compounds are in turn encased in an iron layer that strongly impedes the transmission of neutrons with energies above 24 KeV. Lower energy neutrons readily pass through this iron filter, which has a deep window in its scattering cross section at 24 KeV. The DISCOS concept uses a rapidly rotating, high g disc to create a series of thin ({approximately} 1 micron thickness) liquid lithium targets in the form of continuous films or sheets of discrete droplets--through which the proton beam passes. The average energy lost by a proton as it passes through a single target is small, approximately 10 KeV. Between the targets, the proton beam is re-accelerated by an applied DC electric field. The DISCOS approach enables the accelerator--target facility to operate with a beam energy only slightly above the threshold value for neutron production--resulting in an output beam of low-energy epithermal neutrons--while achieving a high yield of neutrons per milliamp of proton beam current. Parametric trade studies of the NIFTI and DISCOS concepts are described. These include analyses of a broad range of NIFTI designs using the Monte carlo MCNP neutronics code, as well as mechanical and thermal-hydraulic analyses of various DISCOS designs.

  3. Target and filter concepts for accelerator-driven boron neutron capture therapy applications

    SciTech Connect

    Powell, J.R.; Ludewig, H.; Todosow, M.; Reich, M. [Brookhaven National Lab., Upton, NY (United States). Dept. of Advanced Technology

    1999-01-01

    Two new accelerator target and neutron filter concepts are proposed for boron neutron capture therapy (BNCT) to enable production efficiencies for epithermal neutrons (i.e., neutrons leaving the treatment port and neutrons generated in the target) of {approximately}5 to 10%. These efficiencies are much greater than in previous designs and allow BNCT facilities to use near-term, low-current ({approximately}5 mA) proton accelerators. Two target/filter designs are described and their neutronic performance analyzed. In NIFTI-1, epithermal neutrons (maximum energy of {approximately}100 keV) are generated by a proton beam that is maintained slightly above the 1,889-MeV threshold for the {sup 7}Li(p,n){sup 7}Be reaction. As the proton beam passes through the DISCOS target, which consists of a sequential series (e.g., total of 80) of very thin (several microns) liquid-lithium films on ultrathin rotating beryllium metal foils, the protons are reaccelerated by an applied direct-current field between the foils. This reacceleration enables a high total neutron yield, {approximately}10{sup {minus}4} neutrons/proton. The NIFTI-1 neutron filter, a highly scattering cross-section layer of iron-magnesium, located between the target and the treatment port, impedes neutron transmission for energies >24 keV, but it has a deep window in the scattering cross section at 24 keV. Scattering in the filter and an accompanying thin ({approximately}1 cm) hydrogenous neutron downshifter yield a neutron output beam with an average energy of {approximately}10 to 20 keV. In the NIFTI-2 design, a single thick lithium target is used, with a proton beam energy ({approximately}2.5 MeV) well above the (p,n) threshold. Although the neutron yield from the target is high, {approximately}1010{sup {minus}4} neutrons/proton, their energy is much greater (maximum of {approximately}800 keV) than in NIFTI-1. The high-energy neutrons inelastically scatter in a fluorine-containing material (BeF{sub 2}/PbF{sub 2}) placed between the target and the NIFTI filter. The neutron beam out of the treatment port has an average energy of {approximately}30 keV. The effectiveness of the two designs for BNCT treatment is analyzed. Both exhibit good penetration in tissue (advantage depth) and tumor/healthy tissue dose (relative biological effectiveness advantage ratio) performance.

  4. Improvement of dose distribution by central beam shielding in boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Sakurai, Yoshinori; Ono, Koji

    2007-12-01

    Since boron neutron capture therapy (BNCT) with epithermal neutron beams started at the Kyoto University Reactor (KUR) in June 2002, nearly 200 BNCT treatments have been carried out. The epithermal neutron irradiation significantly improves the dose distribution, compared with the previous irradiation mainly using thermal neutrons. However, the treatable depth limit still remains. One effective technique to improve the limit is the central shield method. Simulations were performed for the incident neutron energies and the annular components of the neutron source. It was clear that thermal neutron flux distribution could be improved by decreasing the lower energy neutron component and the inner annular component of the incident beam. It was found that a central shield of 4-6 cm diameter and 10 mm thickness is effective for the 12 cm diameter irradiation field. In BNCT at KUR, the depth dose distribution can be much improved by the central shield method, resulting in a relative increase of the dose at 8 cm depth by about 30%. In addition to the depth dose distribution, the depth dose profile is also improved. As the dose rate in the central area is reduced by the additional shielding, the necessary irradiation time, however, increases by about 30% compared to normal treatment.

  5. A comparison of the COG and MCNP codes in computational neutron capture therapy modeling, Part II: gadolinium neutron capture therapy models and therapeutic effects.

    PubMed

    Wangerin, K; Culbertson, C N; Jevremovic, T

    2005-08-01

    The goal of this study was to evaluate the COG Monte Carlo radiation transport code, developed and tested by Lawrence Livermore National Laboratory, for gadolinium neutron capture therapy (GdNCT) related modeling. The validity of COG NCT model has been established for this model, and here the calculation was extended to analyze the effect of various gadolinium concentrations on dose distribution and cell-kill effect of the GdNCT modality and to determine the optimum therapeutic conditions for treating brain cancers. The computational results were compared with the widely used MCNP code. The differences between the COG and MCNP predictions were generally small and suggest that the COG code can be applied to similar research problems in NCT. Results for this study also showed that a concentration of 100 ppm gadolinium in the tumor was most beneficial when using an epithermal neutron beam. PMID:16010124

  6. A parameter study to determine the optimal source neutron energy in boron neutron capture therapy of brain tumours

    NASA Astrophysics Data System (ADS)

    Nievaart, V. A.; Moss, R. L.; Kloosterman, J. L.; van der Hagen, T. H. J. J.; van Dam, H.

    2004-09-01

    The values of the parameters used in boron neutron capture therapy (BNCT) to calculate a given dose to human tissue vary with patients due to different physical, biological and/or medical circumstances. Parameters include the tissue dimensions, the 10B concentration and the relative biological effectiveness (RBE) factors for the different dose components associated with BNCT. Because there is still no worldwide agreement on RBE values, more often than not, average values for these parameters are used. It turns out that the RBE-problem can be circumvented by taking into account all imaginable parameter values. Approaching this quest from another angle: the outcome will also provide the parameters (and values) which influence the optimal source neutron energy. For brain tumours it turns out that the 10B concentration, the RBE factors for 10B as well as fast neutrons, together with the dose limit set for healthy tissue, affect the optimal BNCT source neutron energy. By using source neutrons of a few keV together with neutrons of a few eV, it ensures that, under all imaginable circumstances, a maximum of alpha (and lithium) particles can be delivered in the tumour.

  7. Dosimetry of 252Cf sources for neutron radiotherapy with and without augmentation by boron neutron capture therapy.

    PubMed

    Yanch, J C; Zamenhof, R G

    1992-09-01

    Interstitial and intracavity 252Cf sources have been used to treat a number of tumor types with encouraging results. In particular these tumors include a variety of cervical, head-and-neck, and oral-cavity cancers and possible malignant gliomas. As a neutron source, 252Cf offers certain theoretical advantages over photon therapy (i.e., in treating tumors with significant hypoxic or necrotic components). With the recent availability of 10B-labeled tumor-seeking compounds, the usefulness of 252Cf may be further improved by augmenting the 252Cf dose to the tumor with an additional dose due to the fission (following thermal neutron capture) of 10B located in the tumor itself. While the high mean neutron energy permits 252Cf to deliver a high-LET, low-OER dose to the tumor on a macroscopic scale, thermalization of neutrons followed by 10B capture may augment this dose at the cellular level if adequate loading of tumor cells with 10B is possible. This paper presents results of a Monte Carlo simulation study investigating the dosimetric characteristics of linear 252Cf sources both with and without the quantitative increase in tumor dose possible with the addition of 10B. Results are displayed in the form of "along and away" tables and dose profiles in a water phantom. Comparisons of Monte Carlo results with experimental and analytical dosimetry data available in the literature are also presented. PMID:1438684

  8. Neutron capture cross section measurement of 151Sm at the CERN neutron time of flight facility (n_TOF).

    PubMed

    Abbondanno, U; Aerts, G; Alvarez-Velarde, F; Alvarez-Pol, H; Andriamonje, S; Andrzejewski, J; Badurek, G; Baumann, P; Becvár, F; Benlliure, J; Berthoumieux, E; Calviño, F; Cano-Ott, D; Capote, R; Cennini, P; Chepel, V; Chiaveri, E; Colonna, N; Cortes, G; Cortina, D; Couture, A; Cox, J; Dababneh, S; Dahlfors, M; David, S; Dolfini, R; Domingo-Pardo, C; Duran, I; Embid-Segura, M; Ferrant, L; Ferrari, A; Ferreira-Marques, R; Frais-Koelbl, H; Furman, W; Goncalves, I; Gallino, R; Gonzalez-Romero, E; Goverdovski, A; Gramegna, F; Griesmayer, E; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martinez, A; Isaev, S; Jericha, E; Käppeler, F; Kadi, Y; Karadimos, D; Kerveno, M; Ketlerov, V; Koehler, P; Konovalov, V; Krticka, M; Lamboudis, C; Leeb, H; Lindote, A; Lopes, I; Lozano, M; Lukic, S; Marganiec, J; Marrone, S; Martinez-Val, J; Mastinu, P; Mengoni, A; Milazzo, P M; Molina-Coballes, A; Moreau, C; Mosconi, M; Neves, F; Oberhummer, H; O'Brien, S; Pancin, J; Papaevangelou, T; Paradela, C; Pavlik, A; Pavlopoulos, P; Perlado, J M; Perrot, L; Pignatari, M; Plag, R; Plompen, A; Plukis, A; Poch, A; Policarpo, A; Pretel, C; Quesada, J; Raman, S; Rapp, W; Rauscher, T; Reifarth, R; Rosetti, M; Rubbia, C; Rudolf, G; Rullhusen, P; Salgado, J; Soares, J C; Stephan, C; Tagliente, G; Tain, J; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vaz, P; Ventura, A; Villamarin, D; Vincente, M C; Vlachoudis, V; Voss, F; Wendler, H; Wiescher, M; Wisshak, K

    2004-10-15

    The151Sm(n,gamma)152Sm cross section has been measured at the spallation neutron facility n_TOF at CERN in the energy range from 1 eV to 1 MeV. The new facility combines excellent resolution in neutron time-of-flight, low repetition rates, and an unsurpassed instantaneous luminosity, resulting in rather favorable signal/background ratios. The 151Sm cross section is of importance for characterizing neutron capture nucleosynthesis in asymptotic giant branch stars. At a thermal energy of kT=30 keV the Maxwellian averaged cross section of this unstable isotope (t(1/2)=93 yr) was determined to be 3100+/-160 mb, significantly larger than theoretical predictions. PMID:15524972

  9. Neutron Capture Cross Section Measurement of 151Sm at the CERN Neutron Time of Flight Facility (n_TOF)

    NASA Astrophysics Data System (ADS)

    Abbondanno, U.; Aerts, G.; Alvarez-Velarde, F.; Álvarez-Pol, H.; Andriamonje, S.; Andrzejewski, J.; Badurek, G.; Baumann, P.; Be?vá?, F.; Benlliure, J.; Berthoumieux, E.; Calviño, F.; Cano-Ott, D.; Capote, R.; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Cortina, D.; Couture, A.; Cox, J.; Dababneh, S.; Dahlfors, M.; David, S.; Dolfini, R.; Domingo-Pardo, C.; Duran, I.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; Frais-Koelbl, H.; Furman, W.; Goncalves, I.; Gallino, R.; Gonzalez-Romero, E.; Goverdovski, A.; Gramegna, F.; Griesmayer, E.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Isaev, S.; Jericha, E.; Käppeler, F.; Kadi, Y.; Karadimos, D.; Kerveno, M.; Ketlerov, V.; Koehler, P.; Konovalov, V.; Krti?ka, M.; Lamboudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marrone, S.; Martinez-Val, J.; Mastinu, P.; Mengoni, A.; Milazzo, P. M.; Molina-Coballes, A.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; O'Brien, S.; Pancin, J.; Papaevangelou, T.; Paradela, C.; Pavlik, A.; Pavlopoulos, P.; Perlado, J. M.; Perrot, L.; Pignatari, M.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Policarpo, A.; Pretel, C.; Quesada, J.; Raman, S.; Rapp, W.; Rauscher, T.; Reifarth, R.; Rosetti, M.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Soares, J. C.; Stephan, C.; Tagliente, G.; Tain, J.; Tassan-Got, L.; Tavora, L.; Terlizzi, R.; Vannini, G.; Vaz, P.; Ventura, A.; Villamarin, D.; Vincente, M. C.; Vlachoudis, V.; Voss, F.; Wendler, H.; Wiescher, M.; Wisshak, K.

    2004-10-01

    The151Sm(n,?)152Sm cross section has been measured at the spallation neutron facility n_TOF at CERN in the energy range from 1eV to 1MeV. The new facility combines excellent resolution in neutron time-of-flight, low repetition rates, and an unsurpassed instantaneous luminosity, resulting in rather favorable signal/background ratios. The 151Sm cross section is of importance for characterizing neutron capture nucleosynthesis in asymptotic giant branch stars. At a thermal energy of kT=30 keV the Maxwellian averaged cross section of this unstable isotope (t1/2=93 yr) was determined to be 3100±160 mb, significantly larger than theoretical predictions.

  10. Analysis of neutron capture elements in metal-poor stars

    NASA Astrophysics Data System (ADS)

    Mishenina, T. V.; Kovtyukh, V. V.

    2001-05-01

    We derived model atmosphere parameters (Teff, log g, [Fe/H], Vt) for 90 metal-deficient stars (-0.5<[Fe/H]<-3), using echelle spectra from the ELODIE library (Soubiran et al. \\cite{soubet98}). These parameters were analyzed and compared with current determinations by other authors. The study of the following elements was carried out: Mg, Si, Ca, Sr, Y, Ba, La, Ce, Nd, and Eu. The relative contributions of s- and r-processes were evaluated and interpreted through theoretical computations of the chemical evolution of the Galaxy. The chemical evolution models (Pagel & Tautvaišien? \\cite{pagta95}; Timmes et al. \\cite{timet95}) depict quite well the behaviour of [Si/Fe], [Ca/Fe] with [Fe/H]. The trend of [Mg/Fe] compares more favourably with the computations of Pagel & Tautvaišien? (\\cite{pagta95}) than those of Timmes et al. (\\cite{timet95}). The runs of n-capture elements vs. metallicity are described well both by the model of Pagel & Tautvaišien? (\\cite{pagta95}, \\cite{pagta97}) and by the model of Travaglio et al. (\\cite{travet99}) at [Fe/H]>-1.5, when the matter of the Galaxy is sufficiently homogeneous. The analysis of n-capture element abundances confirms the jump in [Ba/Fe] at [Fe/H]=-2.5. Some stars from our sample at [Fe/H]<-2.0 show a large scatter of Sr, Ba, Y, Ce. This scatter is not caused by the errors in the measurements, and may reflect the inhomogeneous nature of the prestellar medium at early stages of galactic evolution. The matching of [Ba/Fe], [Eu/Fe] vs. [Fe/H] with the inhomogeneous model by Travaglio et al. (\\cite{travet01a}) suggests that at [Fe/H]<-2.5, the essential contribution to the n-rich element abundances derives from the r-process. The main sources of these processes may be low mass SN II. The larger dispersion of s-process element abundances with respect to alpha -rich elements may arise both from the birth of metal-poor stars in globular clusters with following different evolutionary paths and (or) from differences in s-element enrichment in Galaxy populations. Based on spectra collected at the Observatoire de Haute-Provence (OHP), France

  11. New concepts for compact accelerator/target for Boron Neutron Capture Therapy

    SciTech Connect

    Powell, J.R.; Ludewig, H.; Todosow, M.; Reich, M.

    1996-12-31

    Two new target concepts, NIFTI and DISCOS, that enable a large reduction in the proton beam current needed to produce epithermal neutrons for BNCT (Boron Neutron Capture Therapy) are described. In the NIFTI concept, high energy neutrons produced by (p, n) reactions of 2.5 MeV protons on Li are down scattered to treatment energies ({approximately} 20 keV) by relatively thin layers of PbF{sub 2} and iron. In the DISCOS concept, treatment energy neutrons are produced directly in a succession of thin ({approximately} 1 micron) liquid Li films on rotating Be foils. These foils interact with a proton beam that operates just above threshold for the (p, n) reaction, with an applied DC field to re-accelerate the proton beam between the target foils.

  12. Final Stage in the Design of a Boron Neutron Capture Therapy facility at CEADEN, Cuba

    SciTech Connect

    Cabal, F. Padilla [Instituto Superior de Tecnologias y Ciencias Aplicadas (InSTEC) (Cuba); Martin, G. [Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN) (Cuba)

    2008-08-11

    A neutron beam simulation study is carried out to determine the most suitable neutron energy for treatment of shallow and deep-seated brain tumors in the context of Boron Neutron Capture Therapy (BNCT). Two figures-of-merit, the therapeutic gain and the neutron fluence are utilized as beam assessment parameters. An irradiation cavity is used instead of a parallel beam port for the therapy. Calculations are performed using the MCNP5 code. After the optimization of our beam-shaper a study of the dose distribution in the head, neck, tyroids, lungs and upper and middle spine had been made. The therapeutic gain is increased while the current required for one hour treatment is decreased in comparison with the trading prototypes of NG used for BNCT.

  13. Neutron capture on {sup 94}Zr: Resonance parameters and Maxwellian-averaged cross sections

    SciTech Connect

    Tagliente, G. [Istituto Nazionale di Fisica Nucleare (INFN), Bari (Italy); University of Gent (Belgium); Milazzo, P. M.; Fujii, K.; Abbondanno, U.; Belloni, F.; Moreau, C. [Istituto Nazionale di Fisica Nucleare (INFN), Trieste (Italy); Aerts, G.; Andriamonje, S.; Berthoumieux, E.; Dridi, W.; Gunsing, F.; Pancin, J.; Perrot, L.; Plukis, A. [CEA/Saclay-IRFU, Gif-sur-Yvette (France); Alvarez, H.; Duran, I.; Paradela, C. [Universidade de Santiago de Compostela (Spain); Alvarez-Velarde, F.; Cano-Ott, D.; Embid-Segura, M. [Centro de Investigaciones Energeticas Medioambientales y Technologicas, Madrid (Spain)

    2011-07-15

    The neutron capture cross sections of the Zr isotopes play an important role in nucleosynthesis studies. The s-process reaction flow between the Fe seed and the heavier isotopes passes through the neutron magic nucleus {sup 90}Zr and through {sup 91,92,93,94}Zr, but only part of the flow extends to {sup 96}Zr because of the branching point at {sup 95}Zr. Apart from their effect on the s-process flow, the comparably small isotopic (n,{gamma}) cross sections make Zr also an interesting structural material for nuclear reactors. The {sup 94}Zr (n,{gamma}) cross section has been measured with high resolution at the spallation neutron source n{sub T}OF at CERN and resonance parameters are reported up to 60 keV neutron energy.

  14. Dose calculation from a D-D-reaction-based BSA for boron neutron capture synovectomy.

    PubMed

    Abdalla, Khalid; Naqvi, A A; Maalej, N; Elshahat, B

    2010-01-01

    Monte Carlo simulations were carried out to calculate dose in a knee phantom from a D-D-reaction-based Beam Shaping Assembly (BSA) for Boron Neutron Capture Synovectomy (BNCS). The BSA consists of a D(d,n)-reaction-based neutron source enclosed inside a polyethylene moderator and graphite reflector. The polyethylene moderator and graphite reflector sizes were optimized to deliver the highest ratio of thermal to fast neutron yield at the knee phantom. Then neutron dose was calculated at various depths in a knee phantom loaded with boron and therapeutic ratios of synovium dose/skin dose and synovium dose/bone dose were determined. Normalized to same boron loading in synovium, the values of the therapeutic ratios obtained in the present study are 12-30 times higher than the published values. PMID:19828325

  15. [Epithermal neutron capture therapy]. Progress and status report

    SciTech Connect

    Not Available

    1993-05-01

    Development of a 4 mA, 2.5 MeV Tandem Cascade Accelerator (TCA) for the production of neutrons via the {sup 7}Li(p,n){sup 7}Be nuclear reaction is currently nearing completion at SRL. The TCA is a tandem electrostatic accelerator which uses a high current negative ion source in conjunction with a high current solid state cascade multiplier power supply to provide a compact, low cost, proton accelerator capable of supplying multi-milliampere currents at several million electron volts. The inherent simplicity and flexibility of this accelerator provide several features which are desirable for laboratory and clinical applications requiring the generation of high neutron fluxes. The beam aperture of the accelerating tube is large so that critical focusing and alignment of the beam is not required. Both the ion beam source and target are at ground potential during operation. This configuration allows different moderator geometries to be incorporated easily into the target design. A high degree of compactness is achieved by a patented SRL design which allows the power supply to be mounted directly onto the accelerating column thereby eliminating the need for an external power supply chassis. The TCA is unique in its capability to accelerate multi-milliampere ion beams to 2.5 MeV. A direct result of the patented high current solid-state power supply developed by SRL and the use of a high current, high brightness multicusp negative ion source. The TCA requires no RF or magnetic fields which greatly reduces the system weight, power dissipation and heat load on auxiliary systems when compared with radiofrequency quadrupole (RFQ) or cyclotron-type accelerators. Delivery of current is continuous, rather than pulsed as in an RFQ, which reduces the peak thermal and mechanical stresses on the target and simplifies target design. The accelerator weighs less than 2,000 lbs., has an overall length of approximately 2.6 m, and requires approximately 25 kW of electrical power.

  16. Radiative Capture Cross Sections of 139La(n, ?) for Thermal Neutrons

    NASA Astrophysics Data System (ADS)

    Ureche, Adriana; Hurst, Aaron M.; Goldblum, Bethany L.; Vujic, Jasmina; Firestone, Richard B.; Basunia, Shamsuzzoha; Revay, Zsolt; Szentmiklosi, Laszlo; Belgya, Tamas; Summers, Neil C.; Bernstein, Lee A.; Bleuel, Darren L.; Escher, Jutta E.; Sleaford, Bradley W.; Krticka, Milan

    2014-09-01

    A set of partial-production neutron-capture ?-ray cross sections corresponding to the 139La (n , ?) reaction were measured at the Budapest Research Reactor using a supermirror-guided near-thermal neutron beam. Absolute values for these quantities were obtained through an internal-standardization procedure where the observed ?-ray intensities were normalized to well-known comparator 35Cl(n , ?) transitions using a LaCl3 . 7H2 O standard. These measurements have been used, together with statistical-model predictions calculated using the Monte Carlo program DICEBOX to simulate the thermal-capture ?-ray cascade, to evaluate the decay scheme of the compound nucleus 140La. An independent measurement of the total radiative thermal neutron-capture cross section, ?0, has also been determined; our preliminary result ?0 = 8 . 51 (43) b, is consistent with earlier literature. The total mean capture-state width is currently being investigated and may provide further insight into the validity of the Brink hypothesis in ? decay.

  17. Resonance neutron-capture cross sections of stable magnesium isotopes and their astrophysical implications

    SciTech Connect

    Pigni, Marco T [ORNL; Massimi, C. [Universita di Bologna; Vannini, G. [Universita di Bologna; Koehler, Paul [ORNL; Bisterzo, S. [University of Turin, Turin, Italy; Gallino, R. [University of Turin, Turin, Italy; Colonna, N. [Instituto Nazionale di Fisica Nucleare, Bari, Italy; Lorusso, G. [1st Nazl Fis Nucl, Bari, Italy; Barbagallo, M. [Instituto Nazionale di Fisica Nucleare, Bari, Italy; Marrone, S. [Instituto Nazionale di Fisica Nucleare, Bari, Italy; Tagliente, G. [Instituto Nazionale di Fisica Nucleare, Bari, Italy; Terlizzi, R. [Instituto Nazionale di Fisica Nucleare, Bari, Italy; Gunsing, F. [CEA, Saclay, France; Aerts, G. [CEA, Saclay, France; Andriamonje, S. [CEA, Saclay, France; Berthoumieux, E. [CEA, Saclay, France; Carrapico, C. [CEA, Saclay, France; Dridi, W. [CEA, Saclay, France; Lampoudis, C. [CEA, Saclay, France; Pancin, J. [CEA, Saclay, France; Perrot, L. [CEA, Saclay, France; Plukis, A. [CEA, Saclay, France; Kaeppeler, K. [Institut fur Kernphysik, Karlsruhe, Germany; Dillmann, I. [Institut fur Kernphysik, Karlsruhe, Germany; Mosconi, M. [Karlsruhe Institute of Technology, Karlsruhe, Germany; Plag, R. [Institut fur Kernphysik, Karlsruhe, Germany; Voss, F. [Institut fur Kernphysik, Karlsruhe, Germany; Walter, S. [Institut fur Kernphysik, Karlsruhe, Germany; Wisshak, K. [Institut fur Kernphysik, Karlsruhe, Germany; Mengoni, A. [International Atomic Energy Agency (IAEA); Capote, R. [International Atomic Energy Agency (IAEA); Frais-Koelbl, H. [International Atomic Energy Agency (IAEA); Griesmayer, E. [International Atomic Energy Agency (IAEA); Mengoni, A. [CERN, Geneva, Switzerland; Calviani, M. [CERN, Geneva, Switzerland; Cennini, P. [CERN, Geneva, Switzerland; Chiaveri, E. [CERN, Geneva, Switzerland; Dahlfors, M. [CERN, Geneva, Switzerland; Ferrari, A. [CERN, Geneva, Switzerland; Fitzpatrick, L. [CERN, Geneva, Switzerland; Herrera-Martinez, A. [CERN, Geneva, Switzerland; Kadi, Y. [CERN, Geneva, Switzerland; Losito, R. [CERN, Geneva, Switzerland; Sarchiapone, L. [CERN, Geneva, Switzerland; Vlachoudis, V. [CERN, Geneva, Switzerland; Wendler, H. [CERN, Geneva, Switzerland; Pignatari, M. [Universitat Basel, Switzerland; Rauscher, T. [Universitat Basel, Switzerland; Abbondanno, U. [Instituto Nazionale de Fisica Nucleare, Trieste, Italy; Belloni, F. [Instituto Nazionale de Fisica Nucleare, Trieste, Italy; Fujii, K. [Instituto Nazionale de Fisica Nucleare, Trieste, Italy; Milazzo, P. M. [Instituto Nazionale de Fisica Nucleare, Trieste, Italy; Moreau, C. [Instituto Nazionale de Fisica Nucleare, Trieste, Italy; Alvarez, H. [University of Santiago de Compostela, Spain; Duran, I. [Universidad de Santiago de Compostela; Paradela, C. [University of Santiago de Compostela, Spain; Tarrio, D. [University of Santiago de Compostela, Spain; Alvarez-Velarde, F. [Centro de Investigaciones Energeticas Medioambientales y Technol., Madrid, Spain; Cano-Ott, D. [CIEMAT, Madrid; Embid-Segura, M. [Centro de Investigaciones Energeticas Medioambientales y Technol., Madrid, Spain; Gonzalez-Romero, E. [CIEMAT, Madrid; Guerrero, C. [Centro de Investigaciones Energeticas Medioambientales y Technol., Madrid, Spain; Martinez, T. [Centro de Investigaciones Energeticas Medioambientales y Technol., Madrid, Spain; Mendoza, E. [Centro de Investigaciones Energeticas Medioambientales y Technol., Madrid, Spain; Villamarin, D. [Centro de Investigaciones Energeticas Medioambientales y Technol., Madrid, Spain; Andrzejewski, J. [University of Lodz, Lodz, Poland; Marganiec, J. [University of Lodz; Assimakopoulos, P. A. [University of Ioannina, Greece; Karadimos, D. [University of Ioannina, Greece; Karamanis, D. [University of Ioannina, Greece; Papachristodoulou, C. [University of Ioannina, Greece; Patronis, N. [University of Ioannina, Greece; Audouin, L. [Universite Paris XI, Orsay, France; et al.

    2012-01-01

    We have measured the neutron capture cross sections of the stable magnesium isotopes {sup 24,25,26}Mg in the energy range of interest to the s process using the neutron time-of-flight facility n{_}TOF at CERN. Capture events from a natural metal sample and from samples enriched in {sup 25}Mg and {sup 26}Mg were recorded using the total energy method based on C{sub 6}{sup 2}H{sub 6} detectors. Neutron resonance parameters were extracted by a simultaneous resonance shape analysis of the present capture data and existing transmission data on a natural isotopic sample. Maxwellian-averaged capture cross sections for the three isotopes were calculated up to thermal energies of 100 keV and their impact on s-process analyses was investigated. At 30 keV the new values of the stellar cross section for {sup 24}Mg, {sup 25}Mg, and {sup 26}Mg are 3.8 {+-} 0.2 mb, 4.1 {+-} 0.6 mb, and 0.14 {+-} 0.01 mb, respectively.

  18. Stellar neutron capture cross section of the unstable s-process branching point 151Sm

    NASA Astrophysics Data System (ADS)

    Wisshak, K.; Voss, F.; Käppeler, F.; Krti?ka, M.; Raman, S.; Mengoni, A.; Gallino, R.

    2006-01-01

    The neutron capture cross sections of the radioactive isotope 151Sm and of natural samarium have been measured in the energy range from 3 keV to 225 keV at the Karlsruhe 3.7 MV Van de Graaff accelerator. Neutrons were produced via the 7Li(p,n)7Be reaction by bombarding metallic Li targets with a pulsed proton beam and capture events were registered with the Karlsruhe 4? Barium Fluoride Detector. The cross sections were determined relative to the gold standard using a 206 mg sample of samarium oxide with 90% enrichment in 151Sm. Over most of the measured energy range uncertainties of ~2 3% could be achieved for the 151Sm/197Au ratio. Maxwellian averaged neutron capture cross sections of 151Sm were calculated for thermal energies between kT = 8 keV and 100 keV with due consideration of the stellar enhancement factor and were found to be systematically larger than all previous theoretical predictions used in the analysis of the s-process branching at 151Sm. In the context of the branching analysis, an experimental determination of the stellar enhancement factor due to captures in thermally excited states is proposed, and the tentative determination of the p-process residual of 152Gd and a few other cases is discussed.

  19. Diversity of abundance patterns of neutron-capture elements in very metal-poor stars

    SciTech Connect

    Aoki, Misa; Ishimaru, Yuhri [International Christian University 10-2, Osawa, Mitaka, Tokyo 181-0015 (Japan); Aoki, Wako; Wanajo, Shinya [National Astronomical Observatory of Japan (NAOJ) 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2014-05-02

    Observations of Very Metal-Poor stars indicate that there are at least two sites to r-process; “weak r-process” and “main r-process”. A question is whether these two are well separated or there exists a variation in the r-process. We present the results of abundance analysis of neutron-capture elements in the two Very Metal-Poor stars HD107752 and HD110184 in the Milky Way halo observed with the Subaru Telescope HDS. The abundance patterns show overabundace at light n-capture elements (e.g. Sr, Y), inferring the element yielding of weak r-process, while heavy neutron-capture elements (e.g. Ba, Eu) are deficient; however, the overabundance of light ones is not as significant as that previously found in stars representing the weak r-process (e.g. HD122563; Honda et al. 2006). Our study show diversity in the abundance patterns from light to heavy neutron-capture elements in VMP stars, suggesting a variation in r-process, which may depend on electron fraction of environment.

  20. Monte Carlo simulation of biological effects of boron neutron capture irradiation with d(14)+Be neutrons in vitro

    SciTech Connect

    Poeller, F.; Sauerwein, W. [Univ. of Essen (Germany)

    1995-04-01

    It was shown that radiation effects in tumor cells treated with fast neutrons may be increased by the neutron capture reaction {sup 10}B(n,{alpha}){sup 7}Li. The classic approach for macroscopic dosimetry in fast-neutron therapy cannot be applied to the dose in boron neutron capture therapy (BNCT). The effectiveness of BNCT in killing tumor cells depends on the number of {sup 10}B atoms delivered to the tumor, the subcellular distribution of {sup 10}B and the thermal neutron fluence at the site of the tumor. Monte Carlo calculations of the energy dispositions of short-range particles with high LET coming from {sup 10}B disintegrations were performed and compared to the observed biological effects. The simulation allows us to study the influence of the localization of intracellular {sup 10}B in the nucleus, cytoplasm, plasma membrane or extracellular space. The biological response function which describes the probability of the lethal effect produced by a single particle track through the cell nucleus was found by comparing the calculated microscopic dose distribution spectra for single events with the survival observed experimentally. Calculations for a human melanoma cell population treated as a monolayer in the presence or absence of boron with d(14)+Be neutrons will be demonstrated. Two different boron compounds enriched in {sup 10}B were investigated in this study: boric acid (H{sub 3}{sup 10}BO{sub 3}) and p-dihydroxyboryl phenylalanine (BPA). The study shows that a high fraction of BPA enters the cytoplasm while boric acid was found only in the extracellular space. The computer simulations indicate that BPA yields a higher potential effectiveness for inactivation of melanoma cells than boric acid. 52 refs., 9 figs., 3 tabs.

  1. Mixed-field dosimetry measurement of a target assembly for an accelerator-based neutron source for boron neutron capture therapy

    Microsoft Academic Search

    M. K. Reed; M. C. Dobelbower; J. E. Woollard; T. E Blue

    1998-01-01

    The objective of this work was to measure the neutron and gamma-ray absorbed dose components for a target assembly for an Accelerator-Based Neutron Source (ABNS) for Boron Neutron Capture Therapy (BNCT), and to compare these measurements with MCNP calculations in order to verify the calculations of the in-air neutron and gamma-ray absorbed dose components. The measurements were made using the

  2. Optimization of a moderator assembly for use in an accelerator-based neutron source for boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Woollard, Jeffrey Earl

    In this dissertation, the development and application of in-phantom neutron field optimization parameters for use in evaluating neutron fields for Boron Neutron Capture Therapy (BNCT) is presented. These parameters are based on dose rate distributions in a head phantom and include the effects of fractionation and an energy dependent normal-tissue neutron RBE. As a step in the development of these parameters, a methodology for calculating the energy dependent normal-tissue neutron RBE, RBE(Esbn), was developed. This methodology was used to obtain reasonable estimates for the RBE of neutrons, as a function of neutron energy, for skeletal muscle and brain tissue. Additionally, a sensitivity analysis was performed to examine the robustness of the calculations of RBE(Esbn) to necessary assumptions regarding the level of cell-survival at tolerance for brain. This analysis showed that differences in the RBE-dose rate as a function of depth in an ellipsoidal head phantom, as a result of different assumptions regarding the level of cell-survival at tolerance, were negligible, thus increasing our confidence in our mathematical method. The in-phantom neutron field optimization parameters were used to evaluate the neutron fields produced by several potential moderator assemblies and to determine the optimum moderator assembly for use in our Accelerator-Based Neutron Source (ABNS) for BNCT. Based on a comparison of the calculated in-phantom neutron field optimization parameters, for a single irradiation from the superior aspect, a 10 mA proton beam current, and the specified treatment parameters, a BeO-Lisb2COsb3 moderator assembly, with a 20 cm thick BeO moderator, was found to be the optimum moderator assembly for use in the ABNS. The second best moderator assembly was a Dsb2O-Lisb2COsb3 moderator assembly with a 25 cm thick Dsb2O moderator. An optimization analysis, based on in-air optimization parameters, was also performed on the same moderator assemblies considered in the in-phantom moderator assembly optimization analysis. This analysis concluded that the moderator assemblies shown as optimum in the in-phantom moderator assembly optimization analysis, were also the optimum moderator assemblies based on the in-air parameters. This indicates that both types of parameters agree on the optimal neutron field for use in an ABNS for BNCT.

  3. EPICS Slow Controls System in the Search for a Neutron Electric Dipole Moment

    NASA Astrophysics Data System (ADS)

    Taylor, Courtney

    2006-10-01

    The measurement of a nonzero electric dipole moment (EDM) of the neutron would significantly impact our understanding of the nature of the electro-weak and strong interactions. The goal of the current experiment is to improve the measurement sensitivity of the EDM by two orders of magnitude. The experiment is based on the magnetic-resonance technique of rotating a magnetic dipole moment in a magnetic field. The measurement of the neutron EDM comes from a measurement of the difference in the precession frequencies of neutrons when a strong electric field parallel to the magnetic field is reversed. This construction project is divided into a number of subsystems, five of which require automated control. The Experimental Physics and Industrial Control System (EPICS) is a slow-controls data acquisition (DAQ) system and is the system of choice for this experiment. It was selected for both its ease of use and ability to act as a total control system for large systems. As part of the initial research and development for the EDM project, we are setting up a prototype system that will eventually be copied and sent to the subsystem managers. This prototype consists of a VME crate housing a single board computer and DAQ modules. EPICS, running on a PC with CentOS Linux-x86, interfaces with the VME single board computer and provides a graphical user interface for the control system. The details on building this prototype DAQ system will be presented. Supported in part by the U.S. DoE.

  4. Quantitative neutron capture radiography for studying the biodistribution of tumor-seeking boron-containing compounds.

    PubMed

    Gabel, D; Holstein, H; Larsson, B; Gille, L; Ericson, G; Sacker, D; Som, P; Fairchild, R G

    1987-10-15

    Biodistribution of two compounds presently considered for use in neutron capture therapy has been studied in mice carrying a transplantable Harding-Passey melanoma. A method is described by which quantitative assessment can be made of the boron distribution in whole-body sections of such animals. An alpha-particle-sensitive film is placed in close contact with a freeze-dried section of an animal and exposed to neutrons. The tracks visible after etching are analyzed optoelectronically in fields of 0.6 X 0.6 mm2 and compared to standards of boron homogeneously distributed in liver homogenates. The dynamic range of this method is about two orders of magnitude in concentration, with a lower detection limit of 0.1 to 0.01 ppm 10B, depending on the rate of induction of spurious tracks by fast neutrons present in the neutron beam chosen. In a transplantable Harding-Passey melanoma in mice, it was found that the sulfhydryl boron hydride Na2B12H11SH presently used for therapy of glioblastoma clears blood, muscle, and brain very rapidly. Its accumulation in tumors was persistent for more than three days. A higher tumor accumulation was observed with its disulfide, which has been suggested for neutron capture therapy. For both compounds, a marked heterogeneity of boron distribution within one tumor was found. PMID:3652047

  5. Evaluation of an iron-filtered epithermal neutron beam for neutron-capture therapy

    SciTech Connect

    Musolino, S.V. (Safety and Environmental Protection Division, Brookhaven National Laboratory, Upton, NY (USA)); McGinley, P.H. (Nuclear Engineering and Health Physics, Georgia Institute of Technology, Atlanta, GA (USA)); Greenwood, R.C. (Idaho National Engineering Laboratory, P.O. Box 1625, Idaho Falls, ID (USA)); Kliauga, P. (College of Physicians and Surgeons, Columbia University, 630 West 168th Street NY (USA)); Fairchild, R.G. (Medical Department, Brookhaven National Laboratory, Upton, NY (USA))

    1991-07-01

    An epithermal neutron filter using iron, aluminum, and sulfur was evaluated to determine if the therapeutic performance could be improved with respect to aluminum--sulfur-based filters. An empirically optimized filter was developed that delivered a 93% pure beam of 24-keV epithermal neutrons. It was expected that a thick filter using iron with a density thickness {gt}200 g/cm{sup 2} would eliminate the excess gamma contamination found in Al--S filters. This research showed that prompt gamma production from neutron interactions in iron was the dominant dose component. Dosimetric parameters of the beam were determined from the measurement of absorbed dose in air, thermal neutron flux in a head phantom, neutron and gamma spectroscopy, and microdosimetry.

  6. Boron neutron capture therapy (BNCT) in Finland: technological and physical prospects after 20 years of experiences.

    PubMed

    Savolainen, Sauli; Kortesniemi, Mika; Timonen, Marjut; Reijonen, Vappu; Kuusela, Linda; Uusi-Simola, Jouni; Salli, Eero; Koivunoro, Hanna; Seppälä, Tiina; Lönnroth, Nadja; Välimäki, Petteri; Hyvönen, Heini; Kotiluoto, Petri; Serén, Tom; Kuronen, Antti; Heikkinen, Sami; Kosunen, Antti; Auterinen, Iiro

    2013-05-01

    Boron Neutron Capture Therapy (BNCT) is a binary radiotherapy method developed to treat patients with certain malignant tumours. To date, over 300 treatments have been carried out at the Finnish BNCT facility in various on-going and past clinical trials. In this technical review, we discuss our research work in the field of medical physics to form the groundwork for the Finnish BNCT patient treatments, as well as the possibilities to further develop and optimize the method in the future. Accordingly, the following aspects are described: neutron sources, beam dosimetry, treatment planning, boron imaging and determination, and finally the possibilities to detect the efficacy and effects of BNCT on patients. PMID:22613369

  7. A new target concept for proton accelerator driven boron neutron capture therapy applications

    SciTech Connect

    Powell, J.R.; Ludewig, H.; Todosow, M.; Reich, M.

    1998-11-01

    A new target concept termed Discs Incorporating Sector Configured Orbiting Sources (DISCOS), is proposed for spallation applications, including BNCT (Boron Neutron Capture Therapy). In the BNCT application a proton beam impacts a sequence of ultra thin lithium DISCOS targets to generate neutrons by the {sup 7}Li(p,n){sup 7}Be reaction. The proton beam loses only a few keV of its {approximately}MeV energy as it passes through a given target, and is re-accelerated to its initial energy, by a DC electric field between the targets.

  8. Tandem-ESQ for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT)

    NASA Astrophysics Data System (ADS)

    Kreiner, A. J.; Kwan, J. W.; Burlon, A. A.; Di Paolo, H.; Henestroza, E.; Minsky, D.; Valda, A.; Debray, M.; Somacal, H. R.

    2007-02-01

    A folded tandem, with 1.25 MV terminal voltage, combined with an ElectroStatic Quadrupole (ESQ) chain is being proposed as a machine for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT). The machine is shown to be capable of accelerating a 30 mA proton beam to 2.5 MeV. These are the specifications needed to produce sufficiently intense and clean epithermal neutron beams, based on the on the 7Li(p,n)7Be reaction, to perform BNCT treatment for deep seated tumors in less than an hour.

  9. Parametric study of dynamic s-process neutron-capture nucleosynthesis: nuclear data needs

    SciTech Connect

    Mathews, G.J.; Howard, W.M.; Takahashi, K.; Ward, R.A.

    1984-09-01

    We summarize the stellar parameters which characterize the s-process sigma N curve in the framework of models which produce an exponential distribution of exposures by periodic time-dependent neutron irradiations. The optimum parameter space, defined by the best fit to the solar-system sigma N curve, is distinctively different than the classical smooth monotonically decreasing curve. Constraints are placed on the s-process environment. The needs for better neutron-capture data in various mass regions are highlighted. 19 references.

  10. Feasibility study on pinhole camera system for online dosimetry in boron neutron capture therapy.

    PubMed

    Katabuchi, Tatsuya; Hales, Brian; Hayashizaki, Noriyosu; Igashira, Masayuki; Khan, Zareen; Kobayashi, Tooru; Matsuhashi, Taihei; Miyazaki, Koichi; Ogawa, Koichi; Terada, Kazushi

    2014-06-01

    The feasibility of a pinhole camera system for online dosimetry in boron neutron capture therapy (BNCT) was studied. A prototype system was designed and built. Prompt ?-rays from the (10)B(n,?)(7)Li reaction from a phantom irradiated with neutrons were detected with the prototype system. An image was reconstructed from the experimental data. The reconstructed image showed a good separation of the two borated regions in the phantom. The counting rates and signal-to-noise ratio when using the system in actual BNCT applications are also discussed. PMID:24433991

  11. The decays of ??,?²Ga to levels of ??,?²Ge and the neutron capture cross sections of ??,?¹Ga.

    PubMed

    Krane, K S

    2012-08-01

    The decays of 21-min (70)Ga and 14-h (72)Ga have been studied from neutron-irradiated Ga. Several discrepancies in previous studies are resolved and inconsistencies in the previous (72)Ge data set are addressed. New values are proposed for the energies and ?-decay branchings of the (72)Ge levels. Energies and intensities of the (70)Ga ? rays are also discussed. A new measurement and critical discussion of the (72)Ga half-life is offered. Measurements of the (69)Ga and (71)Ga thermal neutron capture cross sections and resonance integrals are also reported. PMID:22738841

  12. Dose point kernel for boron-11 decay and the cellular S values in boron neutron capture therapy

    SciTech Connect

    Ma Yunzhi; Geng Jinpeng; Gao Song; Bao Shanglian [Research Center for Tumor Diagnosis and Radiotherapy Physics and Laboratory of Medical Physics and Engineering, Peking University, Beijing 100871 (China); Department of Nuclear Physics, Chinese Institute of Atomic Energy, Beijing, 102413 (China); Research Center for Tumor Diagnosis and Radiotherapy Physics and Laboratory of Medical Physics and Engineering, Peking University, Beijing 100871 (China)

    2006-12-15

    The study of the radiobiology of boron neutron capture therapy is based on the cellular level dosimetry of boron-10's thermal neutron capture reaction {sup 10}B(n,{alpha}){sup 7}Li, in which one 1.47 MeV helium-4 ion and one 0.84 MeV lithium-7 ion are spawned. Because of the chemical preference of boron-10 carrier molecules, the dose is heterogeneously distributed in cells. In the present work, the (scaled) dose point kernel of boron-11 decay, called {sup 11}B-DPK, was calculated by GEANT4 Monte Carlo simulation code. The DPK curve drops suddenly at the radius of 4.26 {mu}m, the continuous slowing down approximation (CSDA) range of a lithium-7 ion. Then, after a slight ascending, the curve decreases to near zero when the radius goes beyond 8.20 {mu}m, which is the CSDA range of a 1.47 MeV helium-4 ion. With the DPK data, S values for nuclei and cells with the boron-10 on the cell surface are calculated for different combinations of cell and nucleus sizes. The S value for a cell radius of 10 {mu}m and a nucleus radius of 5 {mu}m is slightly larger than the value published by Tung et al. [Appl. Radiat. Isot. 61, 739-743 (2004)]. This result is potentially more accurate than the published value since it includes the contribution of a lithium-7 ion as well as the alpha particle.

  13. A New Thermal Neutron Flux Convention

    Microsoft Academic Search

    T B Ryves

    1969-01-01

    A new thermal neutron flux convention is proposed where the neutron slowing down spectrum per unit energy varies as 1\\/E1+? (| ? ln E | << 1). The neutron capture rate per atom for a detector may be written as n?0 ?0 [Gthg(T) + f C(?, T) Grh(?, Gr)I'\\/?0] where n is the neutron density, ?0 is the conventional 2200

  14. Nuclear structure of 170Tm from neutron-capture and (d,p)-reaction measurements

    NASA Astrophysics Data System (ADS)

    Hoff, R. W.; Börner, H. G.; Schreckenbach, K.; Colvin, G. G.; Hoyler, F.; Schauer, W.; von Egidy, T.; Georgii, R.; Ott, J.; Schründer, S.; Casten, R. F.; Gill, R. L.; Balodis, M.; Prokofjevs, P.; Simonova, L.; Kern, J.; Khitrov, V. A.; Sukhovoj, A. M.; Bersillon, O.; Joly, S.; Graw, G.; Hofer, D.; Valnion, B.

    1996-07-01

    We have made experimental measurements in 170Tm of the following: secondary ? rays, conversion electrons, and ?-? coincidences from thermal neutron capture in 169Tm, primary ? rays from average resonance capture with 2-keV and 24-keV neutron beams, and proton spectra from the (d,p) reaction on 169Tm. From these data and those of previous investigations, we have identified more than 130 excited levels in 170Tm below 1550 keV. Of these, 62 (with connecting transitions) are placed in 18 rotational bands with assigned Nilsson configurations. These results are in good agreement with a semiempirical modeling of 170Tm level structure. Values for seven Gallagher-Moszkowski splittings and four Newby shifts have been obtained. These matrix elements show remarkably good agreement with calculation. Among the observed K?=1- and 2- rotational bands, configuration mixing appears to play a significant role.

  15. Determination of Thermal Neutron Capture Cross-Sections at Budapest PGAA Facility

    SciTech Connect

    Revay, Zsolt; Belgya, Tamas [Institute of Isotopes HAS, H-1525 Budapest POB 77 (Hungary); Firestone, Richard B. [Lawrence Berkeley National Laboratory (United States)

    2007-10-26

    Prompt gamma activation analysis (PGAA) is a powerful nuclear analytical technique to determine the elemental and isotopic composition of materials. The PGAA facility at Budapest, Hungary is one of the leading laboratories of the world, determining spectroscopic data for chemical analysis to be used in other laboratories. These partial gamma-ray production cross-sections and k{sub 0} values, being proportional to the analytical sensitivities of the chemical elements, can be transformed into thermal neutron capture cross-sections, i.e. the probabilities of the (n,{gamma}) reactions, which are of broader interest in different fields of nuclear physics. Some preliminary results on thermal neutron capture cross-sections are presented.

  16. Low-energy level structure of 151Sm by neutron capture reactions and theoretical interpretation

    NASA Astrophysics Data System (ADS)

    Vandenput, G.; van Assche, P. H. M.; Jacobs, L.; van den Cruyce, J. M.; Smither, R. K.; Schreckenbach, K.; von Egidy, T.; Breitig, D.; Baader, H. A.; Koch, H. R.

    1986-04-01

    A nuclear structure study of 151Sm is presented on the basis of low-energy ?-ray and conversion electron spectroscopy, in connection with thermal neutron capture, and high-energy primary ?-ray measurements following average resonance neutron capture. The level scheme is established up to 1020 keV and incorporates 44 levels. Unique spin and parity assignments are made for 34 levels, and narrow limits are set for the remaining levels. Further possible levels are given between 355 and 1220 keV. Theoretical calculations are presented in the framework of the quasiparticle-rotor model, introducing Coriolis coupling and ?N=2 interaction. Comparisons between theoretical and experimental results are made for level energies, branching ratios, and multipole mixing ratios.

  17. DNA double-strand break induction in Ku80-deficient CHO cells following Boron Neutron Capture Reaction

    PubMed Central

    2011-01-01

    Background Boron neutron capture reaction (BNCR) is based on irradiation of tumors after accumulation of boron compound. 10B captures neutrons and produces an alpha (4He) particle and a recoiled lithium nucleus (7Li). These particles have the characteristics of high linear energy transfer (LET) radiation and have marked biological effects. The purpose of this study is to verify that BNCR will increase cell killing and slow disappearance of repair protein-related foci to a greater extent in DNA repair-deficient cells than in wild-type cells. Methods Chinese hamster ovary (CHO-K1) cells and a DNA double-strand break (DSB) repair deficient mutant derivative, xrs-5 (Ku80 deficient CHO mutant cells), were irradiated by thermal neutrons. The quantity of DNA-DSBs following BNCR was evaluated by measuring the phosphorylation of histone protein H2AX (gamma-H2AX) and 53BP1 foci using immunofluorescence intensity. Results Two hours after neutron irradiation, the number of gamma-H2AX and 53BP1 foci in the CHO-K1 cells was decreased to 36.5-42.8% of the levels seen 30 min after irradiation. In contrast, two hours after irradiation, foci levels in the xrs-5 cells were 58.4-69.5% of those observed 30 min after irradiation. The number of gamma-H2AX foci in xrs-5 cells at 60-120 min after BNCT correlated with the cell killing effect of BNCR. However, in CHO-K1 cells, the RBE (relative biological effectiveness) estimated by the number of foci following BNCR was increased depending on the repair time and was not always correlated with the RBE of cytotoxicity. Conclusion Mutant xrs-5 cells show extreme sensitivity to ionizing radiation, because xrs-5 cells lack functional Ku-protein. Our results suggest that the DNA-DSBs induced by BNCR were not well repaired in the Ku80 deficient cells. The RBE following BNCR of radio-sensitive mutant cells was not increased but was lower than that of radio-resistant cells. These results suggest that gamma-ray resistant cells have an advantage over gamma-ray sensitive cells in BNCR. PMID:21888676

  18. The calculation of neutron capture gamma-ray yields for space shielding applications

    NASA Technical Reports Server (NTRS)

    Yost, K. J.

    1972-01-01

    The application of nuclear models to the calculation of neutron capture and inelastic scattering gamma yields is discussed. The gamma ray cascade model describes the cascade process in terms of parameters which either: (1) embody statistical assumptions regarding electric and magnetic multipole transition strengths, level densities, and spin and parity distributions or (2) are fixed by experiment such as measured energies, spin and parity values, and transition probabilities for low lying states.

  19. Optimization of Boron Neutron Capture Therapy for the Treatment of Undifferentiated Thyroid Cancer

    Microsoft Academic Search

    Maria Alejandra Dagrosa; Lisa M. Sc. Thomasz; Juan Longhino; Marina Perona; Osvaldo Calzetta; Herman Blaumann; Raúl Jiménez Rebagliati; Romulo Cabrini; Steven Kahl; Guillermo Juan Juvenal; Mario Alberto Pisarev

    2007-01-01

    Purpose: To analyze the possible increase in efficacy of boron neutron capture therapy (BNCT) for undifferentiated thyroid carcinoma (UTC) by using p-boronophenylalanine (BPA) plus 2,4-bis (,-dihydroxyethyl)-deutero-porphyrin IX (BOPP) and BPA plus nicotinamide (NA) as a radiosensitizer of the BNCT reaction. Methods and Materials: Nude mice were transplanted with a human UTC cell line (ARO), and after 15 days they were

  20. New Methods for the Determination of Total Radiative Thermal Neutron Capture Cross Sections

    Microsoft Academic Search

    R. B. Firestone; M. Krticka; D. P. McNabb; B. Sleaford; U. Agvaanluvsan; T. Belgya; Zs. Revay

    2008-01-01

    Precise gamma-ray thermal neutron capture cross sections have been measured at the Budapest Reactor for all elements with Z = 1-83,92 except for He and Pm. These measurements and additional data from the literature been compiled to generate the Evaluated Gamma-ray Activation File (EGAF), which is disseminated by LBNL and the IAEA. These data are nearly complete for most isotopes

  1. Boron Neutron Capture Therapy in the Treatment of Locally Recurred Head and Neck Cancer

    Microsoft Academic Search

    Leena Kankaanranta; Tiina Seppaelae; Hanna Koivunoro; Kauko Saarilahti; Timo Atula; Juhani Collan; Eero Salli; Mika Kortesniemi; Jouni Uusi-Simola; Antti Maekitie; Marko Seppaenen; Heikki Minn; Petri Kotiluoto; Iiro Auterinen; Sauli Savolainen; Mauri Kouri; Heikki Joensuu

    2007-01-01

    Purpose: Head and neck carcinomas that recur locally after conventional irradiation pose a difficult therapeutic problem. We evaluated safety and efficacy of boron neutron capture therapy (BNCT) in the treatment of such cancers. Methods and Materials: Twelve patients with inoperable, recurred, locally advanced (rT3, rT4, or rN2) head and neck cancer were treated with BNCT in a prospective, single-center Phase

  2. Rat brain tumor models to assess the efficacy of boron neutron capture therapy: a critical evaluation

    Microsoft Academic Search

    Rolf F. Barth; Weilian Yang; Jeffrey A. Coderre

    2003-01-01

    Summary  Development of any therapeutic modality can be facilitated by the use of the appropriate animal models to assess its efficacy.\\u000a This report primarily will focus on our studies using the F98 and 9L rat glioma models to evaluate the effectiveness of boron\\u000a neutron capture therapy (BNCT) of brain tumors. Following intracerebral implantation the biological behavior of each tumor\\u000a resembles that

  3. Neutron Capture Cross Sections of ^234U and ^151Sm Measured at LANSCE

    Microsoft Academic Search

    R. S. Rundberg; J. B. Wilhelmy; G. G. Miller; D. Dry; P. Palmer; M. M. Fowler; J. L. Ullmann; R. C. Haight; L. Hunt

    2002-01-01

    The neutron capture cross section of radioactive and rare stable isotopes are needed both for the improved interpretation of historical nuclear weapons test data and the interpretation of isotopic distributions from s-process and r-process nucleosynthesis. ^151Sm is an important s-process branch point. Accurate cross sections in the energy range from 1 keV to 100 keV are needed to model the

  4. Pharmacokinetics of sodium borocaptate: a critical assessment of dosing paradigms for boron neutron capture therapy

    Microsoft Academic Search

    Christopher R. Gibson; Alfred E. Staubus; Rolf F. Barth; Weilian Yang; Amy K. Ferketich; Melvin M. Moeschberger

    2003-01-01

    Summary  The pharmacokinetics of sodium borocaptate (BSH), a drug that has been used clinically for boron neutron capture therapy (BNCT)\\u000a of malignant brain tumors, have been characterized by measuring boron concentrations by direct current plasma-atomic emission\\u000a spectroscopy (DCP-AES) in a group of 23 patients with high-grade gliomas. The disposition of BSH following intravenous (i.v.)\\u000a infusion, which was determined by measuring plasma

  5. Pharmacokinetics of Sodium Borocaptate: A Critical Assessment of Dosing Paradigms for Boron Neutron Capture Therapy

    Microsoft Academic Search

    Christopher R. Gibson; Alfred E. Staubus; Rolf F. Barth; Weilian Yang; Amy K. Ferketich; Melvin M. Moeschberger

    2003-01-01

    The pharmacokinetics of sodium borocaptate (BSH), a drug that has been used clinically for boron neutron capture therapy (BNCT) of malignant brain tumors, have been characterized by measuring boron concentrations by direct current plasma-atomic emission spectroscopy (DCP-AES) in a group of 23 patients with high-grade gliomas. The disposition of BSH following intravenous (i.v.) infusion, which was determined by measuring plasma

  6. Boron neutron capture therapy for oral precancer: proof of principle in an experimental animal model

    SciTech Connect

    A. Monti Hughes; ECC Pozzi; S. Thorp; M. A. Garabalino; R. O. Farias; S. J. Gonzalez; E. M. Heber; M. E. Itoiz; R. F. Aromando; A. J. Molinari; M. Miller; D. W. Nigg; P. Curotto; V. A. Trivillin; A. E. Schwint

    2013-11-01

    Field-cancerized tissue can give rise to second primary tumours, causing therapeutic failure. Boron neutron capture therapy (BNCT) is based on biological targeting and would serve to treat undetectable foci of malignant transformation. The aim of this study was to optimize BNCT for the integral treatment for oral cancer, with particular emphasis on the inhibitory effect on tumour development originating in precancerous conditions, and radiotoxicity of different BNCT protocols in a hamster cheek pouch oral precancer model.

  7. Analytical sensitivities and energies of thermal neutron capture gamma rays II

    USGS Publications Warehouse

    Senftle, F.E.; Moore, H.D.; Leep, D.B.; El-Kady, A.; Duffey, D.

    1971-01-01

    A table of the analytical sensitivities of the principal lines in the thermal neutron capture gamma-ray spectrum from 0 to 3 MeV has been compiled for most of the elements. A tabulation of the full-energy, single-escape, and double-escape peaks has also been made according to energy. The tables are useful for spectral interpretation and calibration. ?? 1971.

  8. Analytical sensitivities and energies of thermal-neutron-capture gamma rays

    USGS Publications Warehouse

    Duffey, D.; El-Kady, A.; Senftle, F.E.

    1970-01-01

    A table of the analytical sensitivities of the principal lines in the thermal-neutron-capture gamma ray spectrum has been compiled for most of the elements. In addition a second table of the full-energy, single-escape, and double-escape peaks has been compiled according to energy for all significant lines above 3 MeV. Lines that contrast well with adjacent lines are noted as prominent. The tables are useful for spectral interpretation and calibration. ?? 1970.

  9. Experimental evaluation of boron neutron capture therapy of human breast carcinoma implanted on nude mice

    NASA Astrophysics Data System (ADS)

    Bose, Satya Ranjan

    2000-06-01

    An in-pool small animal irradiation neutron tube (SAINT) facility was designed, constructed and installed at the University of Virginia Nuclear Research Reactor (UVAR). Thermal neutron flux profiles were measured by foil activation analysis (gold) and verified with DORT and MCNP computer code models. The gamma-ray absorbed dose in the neutron-gamma mixed field was determined from TLD measurements. The SAINT thermal neutron flux was used to investigate the well characterized human breast cancer cell line MCF-7B on both in-vitro samples and in- vivo animal subjects. Boronophenylalanine (BPA enriched in 95% 10B) was used as a neutron capturing agent. The in-vitro response of MCF-7B human breast carcinoma cells to BPA in a mixed field of neutron-gamma radiation or pure 60Co gamma radiation was investigated. The best result (lowest surviving fraction) was observed in cell cultures pre-incubated with BPA and given the neutron irradiation. The least effective treatment consisted of 60Co irradiation only. Immunologically deficient nude mice were inoculated subcutaneously with human breast cancer MCF-7B cells and estradiol pellets (to support tumor growth). The tumor volume in the mouse control group increased over time, as expected. The group of mice exposed only to neutron treatment exhibited initial tumor volume reduction lasting until 35 days following the treatment, followed by renewed tumor growth. Both groups given BPA plus neutron treatment showed continuous reduction in tumor volume over the 55-day observation period. The group given the higher BPA concentration showed the best tumor reduction response. The results on both in-vitro and in-vivo studies showed increased cell killing with BPA, substantiating the incorporation of BPA into the tumor or cell line. Therefore, BNCT may be a possible choice for the treatment of human breast carcinoma. However, prior to the initiation of any clinical studies, it is necessary to determine the therapeutic efficacy in a large animal model.

  10. Optimization of an accelerator-based epithermal neutron source for neutron capture therapy

    Microsoft Academic Search

    O. E. Kononov; V. N. Kononov; M. V. Bokhovko; V. V. Korobeynikov; A. N. Soloviev; A. S. Sysoev; I. A. Gulidov; W. T. Chu; D. W. Nigg

    2004-01-01

    A modeling investigation was performed to choose moderator material and size for creating optimal epithermal neutron beams for BNCT based on a proton accelerator and the 7Li(p,n)7Be reaction as a neutrons source. An optimal configuration is suggested for the beam shaping assembly made from polytetrafluoroethylene and magnesium fluorine to be placed on high current IPPE proton accelerator KG-2.5. Results of

  11. Optimization of an accelerator-based epithermal neutron source for neutron capture therapy

    SciTech Connect

    Kononov, O.E.; Kononov, V.N.; Bokhovko, M.V.; Korobeynikov, V.V.; Soloviev, A.N.; Chu, W.T.

    2004-02-20

    A modeling investigation was performed to choose moderator material and size for creating optimal epithermal neutron beams for BNCT based on a proton accelerator and the 7Li(p,n)7Be reaction as a neutrons source. An optimal configuration is suggested for the beam shaping assembly made from polytetrafluoroethylene and magnesium fluorine. Results of calculation were experimentally tested and are in good agreement with measurements.

  12. Development of the JAERI computational dosimetry system (JCDS) for boron neutron capture therapy. Cooperative research

    E-print Network

    Kumada, H; Matsumura, A; Nakagawa, Y; Nose, T; Torii, Y; Uchiyama, J; Yamamoto, K; Yamamoto, T

    2003-01-01

    The Neutron Beam Facility at JRR-4 enables us to carry out boron neutron capture therapy with epithermal neutron beam. In order to make treatment plans for performing the epithermal neutron beam BNCT, it is necessary to estimate radiation doses in a patient's head in advance. The JAERI Computational Dosimetry System (JCDS), which can estimate distributions of radiation doses in a patient's head by simulating in order to support the treatment planning for epithermal neutron beam BNCT, was developed. JCDS is a software that creates a 3-dimentional head model of a patient by using CT and MRI images, and that generates a input data file automatically for calculation of neutron flux and gamma-ray dose distributions in the brain with the Monte Carlo code MCNP, and that displays these dose distributions on the head model for dosimetry by using the MCNP calculation results. JCDS has any advantages as follows; By using CT data and MRI data which are medical images, a detail three-dimensional model of patient's head is...

  13. Low-lying levels of 77Se studied by thermal neutron capture and evidence for a new term in the E2 operator of RQM (IBM)

    NASA Astrophysics Data System (ADS)

    Tokunaga, Y.; Seyfarth, H.; Meyer, R. A.; Schult, O. W. B.; Börner, H. G.; Barreau, G.; Faust, H. R.; Schreckenbach, K.; Brant, S.; Paar, V.; Vouk, M.; Vretenar, D.

    1985-06-01

    A high-resolution study of the 76Se(n, ?) reaction was carried out with curved-crystal and pair spectrometers and conversion electrons were measured following slow-neutron capture. The resulting data yield very precise level energies and spin and parity assignments for most of the levels. The neutron separation energy of 77Se was measured as 7418.85 ± 0.07 keV. The experimental data were compared with theoretical results for the level energies in 77Se and the E2, M1 and E1 branching ratios obtained from the SU(6) particle-vibration model (PTQM). We used 76Se as a slightly perturbed SU(5) vibrational core and the particle-vibration interaction strengths from the PTQM calculation for 75Se. In this frame there is evidence for a ?n = 2 term in the E2 operator. This term has not been included so far in TQM and IBM calculations.

  14. Coulomb Dissociation of $^{15}$C and Radiative Neutron Capture on $^{14}$C

    E-print Network

    H. Esbensen

    2009-08-24

    The semiclassical, dynamical description of diffraction dissociation of weakly bound nuclei is applied to analyze the decay-energy spectra of $^{15}$C that have been measured at 68 MeV/nucleon on a Pb target. The optical potentials that are used to describe the nuclear interaction of $^{15}$C with the target nucleus are realistic because the fits to the two measured spectra, one with a small and one with a very large acceptance angle, are consistent and of similar quality. The cross section for the radiative neutron capture on $^{14}$C to the 1/2$^+$ ground state of $^{15}$C is deduced from the analysis. When combined with an estimated contribution from the capture to the 5/2$^+$ excited state of $^{15}$C, an excellent agreement with a recent direct capture measurement is achieved.

  15. Feasibility of using prompt neutron capture gamma rays to detect mercury

    SciTech Connect

    Bell, Z.W.

    1993-10-01

    This report describes a study to determine the feasibility to use neutrons to probe hidden spaces within buildings for the presence of mercury. The study was performed in four phases: First a search of the scientific literature was performed to ascertain the behavior of mercury subsequent to the capture of a thermal or near-thermal neutron. Second, a Monte Carlo investigation (using the code MCNP) of the effects of neutrons on materials expected to be found near and/or surrounding the mercury was undertaken. Third, a Monte Carlo study of the shielding and beam forming properties of various configurations of moderator material was started. Lastly, a Monte Carlo analysis of a likely field situation involving mercury behind 1 inch and 2 inch thicknesses of concrete was performed.

  16. Measurement of the weak nucleon-nucleon interaction by polarized cold neutron capture on protons

    NASA Astrophysics Data System (ADS)

    Alarcon, R.; Blyth, D.

    2014-03-01

    The NPDGamma Experiment at the Spallation Neutron Source at Oak Ridge National Laboratory is measuring the parity-odd correlation between the neutron spin and the direction of the emitted photon in the capture of polarized cold neutrons on protons. A parity violating asymmetry from this process is directly related to the strength of the hadronic weak interaction between nucleons. The experiment was run first with heavier nuclear targets to check systematic effects, false asymmetries, and backgrounds. Since early 2012 the experiment has been collecting data with a 16-liter liquid parahydrogen target. Data taking will continue through 2013 until statistics for a 10-8 asymmetry measurement are expected. The experiment performance will be discussed as well as the status of the asymmetry measurements.

  17. High Resolution Quantitative Auto-Radiography to determine microscopic distributions of B-10 in neutron capture therapy

    E-print Network

    Harris, Thomas C. (Thomas Cameron)

    2006-01-01

    The success of Boron Neutron Capture Therapy (BNCT) is heavily dependent on the microscopic distribution of B-10 in tissue. High Resolution Quantitative Auto-Radiography (HRQAR) is a potentially valuable analytical tool ...

  18. Determination of wax deposition and corrosion in pipelines by neutron back diffusion collimation and neutron capture gamma rays.

    PubMed

    Abdul-Majid, Samir

    2013-04-01

    Wax deposition in pipelines can be very costly for plant operation in oil industry. New techniques are needed for allocation and thickness determination of wax deposits. The timely removal of wax can make large saving in operational cost. Neutron back diffusion and neutron capture gamma rays were used in this study to measure paraffin, asphalt and polyethylene deposition thicknesses inside pipes and to enable simultaneous determination of scale and pipe corrosion. It was possible to determine a thickness change of less than one mm in 2 min. It was also possible to detect localized scale from a small region of the pipe of approximately 2 cm in diameter. Although experiments were performed in lab, the system can be made portable for field applications. PMID:23410615

  19. Neodymium neutron transmission and capture measurements and development of a new transmission detector

    NASA Astrophysics Data System (ADS)

    Barry, Devin P.

    Neodymium is a 235U fission product and is important in reactor neutronic calculations. The aim of this thesis is to improve upon the existing neutron cross section data of neodymium. Neutron capture and transmission measurements were performed by the time-of-flight technique at the Rensselaer Polytechnic Institute LINAC using metallic neodymium samples. The capture measurements were made at the 25-m flight station with a 16-segment Nal multiplicity detector, and the transmission measurements were performed at 15-m and 25-m flight stations, respectively, with 6Li glass scintillation detectors. After the data were collected and reduced, resonance parameters were determined by simultaneously fitting the transmission and capture data with the multilevel R-matrix Bayesian code SAMMY. The resonance parameters for all naturally occurring neodymium isotopes were deduced within the energy range of 1.0 eV to 500 eV. The resulting resonance parameters were used to calculate the capture resonance integral with this energy region and were compared to calculations obtained when using the resonance parameters from ENDF-B/VI. The RPI parameters gave a resonance integral value of 32 +/- 1 barns that is approximately 7% lower than that obtained with the ENDF-B/VI parameters. The current measurements significantly reduce the statistical uncertainties on the resonance parameters when compared with previously published parameters. This thesis also explains the resolution function in detail and discusses its importance when fitting experimental data to extract resonance parameters. More accurate resolution function parameters were determined for epithermal transmission and capture measurements by fitting well known resonances in Uranium-238. Improved transmission bare-bounce target in-beam photomultiplier tube (PMT) resolution function parameters were found and compared to those used previously at the RPI LINAC and a marked improvement in the quality of the fits is shown. In addition to finding improved resolution function parameters, a method was developed to find the 'estimated uncertainty' on these parameters. The 'estimated uncertainty' values for the resolution function parameters were chosen to represent a + or -10% change in the reduced chi-squared value in fits to uranium. This thesis also presents the design, construction, and implementation of a new out-of-beam detector (OBD) system for use in transmission experiments. MCNP modeling was used to validate that the OBD system has less neutron backscatter when compared with the previously used in-beam detector (IBD). This decrease in neutron backscatter offers an overall improvement in resolution function. Experiments were performed with the OBD system using uranium samples and resulting data was used to show this improvement in the resolution function.

  20. Dose point kernel for boron-11 decay and the cellular S values in boron neutron capture therapy

    Microsoft Academic Search

    Yunzhi Ma; Jinpeng Geng; Song Gao; Shanglian Bao

    2006-01-01

    The study of the radiobiology of boron neutron capture therapy is based on the cellular level dosimetry of boron-10's thermal neutron capture reaction ¹°B(n,α)⁷Li, in which one 1.47 MeV helium-4 ion and one 0.84 MeV lithium-7 ion are spawned. Because of the chemical preference of boron-10 carrier molecules, the dose is heterogeneously distributed in cells. In the present work, the

  1. Solid state detector for high spatial resolution coupled to a single event acquisition system for slow neutron detection

    NASA Astrophysics Data System (ADS)

    Casinini, F.; Petrillo, C.; Sacchetti, F.

    2012-05-01

    In the next years the slow neutron scattering community is waiting for a continuous improvement of the neutron detectors because of the development of the new and more intense neutron sources and to obtain a better performance of the neutron instrumentation to face the higher demands and new capabilities necessary for the novel experiments. In particular detectors having a faster response and a better shape of the time response must be produced, while new and more flexible acquisition systems must be introduced in order to collect in the proper way the information carried by the scattered neutrons. At present inside the neutron detector community the lack for detectors having a spatial resolution below 1 mm is evident. In the past it has been already demonstrated that a silicon microstrip detector coupled to a Gadolinium foil, used as neutron converter, provides a good performance neutron detector. In the present paper we present a 128 channel detector which has been designed for operation in the thermal neutron region with 0.55 mm spatial resolution, 100 ns time resolution and 25 ns time stamp accuracy. We present a new approach for the acquisition of the neutron arrival time, based on a single event storage by manipulating the detector digital output using a programmable acquisition system which takes advantage from high performance industrial standard hardware employing a FPGA and a real-time on board processor. We suggest the use of the single neutron event storing to make the time to energy transformation more efficient in the case of time of flight inelastic scattering, where the conversion from angle and time to momentum and energy is necessary.

  2. Study of moderator thickness for an accelerator-based neutron irradiation facility for boron neutron capture therapy using the 7Li(p,n) reaction near threshold.

    PubMed

    Zimin, S; Allen, B J

    2000-01-01

    Accelerator neutron sources for epithermal neutron capture therapy utilizing the 7Li(p,n) nuclear reaction will require a moderator even in the threshold range of 1.89 to 1.95 MeV. The corresponding neutron energies allow for a thinner reflector and moderator, with less reduction of the epithermal flux. To estimate the useful neutron flux within the epithermal range (4 eV-40 keV), the optimal thickness of a heavy water moderator was determined using the two-dimensional neutron transport S(N) code DORT. Optimized results are compared with the epithermal fluxes reported for the higher proton energy range, and are found to be inferior. Thus, this study supports the 2.5-3.0 MeV proton energy range for accelerator boron neutron capture therapy. PMID:10661583

  3. Progress towards boron neutron capture therapy at the High Flux Reactor Petten.

    PubMed

    Moss, R L

    1990-01-01

    During 1988 the first positive steps were taken to proceed with the design and construction of a neutron capture therapy facility on the High Flux Reactor (HFR) at Petten. The immediate aim is to realise within a short time (summer 1989), an epithermal neutron beam for radiobiological and filter optimisation studies on one of the 10 small aperture horizontal beam tubes. The following summer, a much larger neutron beam, i.e., in cross section and neutron fluence rate, will be constructed on one of the two large beam tubes that replaced the old thermal column in 1984. This latter beam tube faces one whole side of the reactor vessel, extending from a 50 x 40 cm input aperture to a 35 x 35 cm exit hole. The radiotherapeutic facility will be housed here, with the intention to start clinical trials at the beginning of 1991. This paper describes the present status of the project and includes: a general description of the pertinent characteristics with respect to NCT of the HFR; results of the recently completed preliminary neutron metrology and computer modeling at the input end of the candidate beam tube; the structure and planning of the proposed Work Programme; and the respective direct and indirect participation and collaboration with the Netherlands Cancer Institute and the European Collaboration Group on BNCT. PMID:2268238

  4. The rationale and requirements for the development of boron neutron capture therapy of brain tumors.

    PubMed

    Soloway, A H; Barth, R F; Gahbauer, R A; Blue, T E; Goodman, J H

    1997-05-01

    The dismal clinical results in the treatment of glioblastoma multiforme despite aggressive surgery, conventional radiotherapy, and chemotherapy, either alone or in combination has led to the development of alternative therapeutic modalities. Among these is boron neutron capture therapy (BNCT). This binary system is based upon two key requirements: (1) the development and use of neutron beams from nuclear reactors or other sources with the capability for delivering high fluxes of thermal neutrons at depths sufficient to reach all tumor foci, and (2) the development and synthesis of boron compounds that can penetrate the normal bloodbrain barrier, selectively target neoplastic cells, and persist therein for suitable periods of time prior to irradiation. The earlier clinical failures with BNCT related directly to the lack of tissue penetration by neutron beams and to boron compounds that showed little specificity for and low retention by tumor cells, while attaining high concentrations in blood. Progress has been made both in neutron beam and compound development, but it remains to be determined whether these are sufficient to improve therapeutic outcomes by BNCT in comparison with current therapeutic regimens for the treatment of malignant gliomas. PMID:9151219

  5. A capture-gated neutron calorimeter using plastic scintillators and 3He drift tubes

    SciTech Connect

    Wang, Zhehui [Los Alamos National Laboratory; Morris, Christopher L [Los Alamos National Laboratory; Spaulding, Randy J [Los Alamos National Laboratory; Bacon, Jeffrey D [Los Alamos National Laboratory; Borozdin, Konstantin N [Los Alamos National Laboratory; Chung, Kiwhan [Los Alamos National Laboratory; Clark, Deborah J [Los Alamos National Laboratory; Green, Jesse A [Los Alamos National Laboratory; Greene, Steven J [Los Alamos National Laboratory; Hogan, Gary E [Los Alamos National Laboratory; Jason, Andrew [Los Alamos National Laboratory; Lisowski, Paul W [Los Alamos National Laboratory; Makela, Mark F [Los Alamos National Laboratory; Mariam, Fessaha G [Los Alamos National Laboratory; Miyadera, Haruo [Los Alamos National Laboratory; Murray, Matthew M [Los Alamos National Laboratory; Saunders, Alexander [Los Alamos National Laboratory; Wysocki, Frederick J [Los Alamos National Laboratory; Gray, Frederick E [REGIS UNIV.

    2010-01-01

    A segmented neutron calorimeter using nine 4-inch x 4-inch x 48-inch plastic scintillators and sixteen 2-inch-diameter 48-inch-long 200-mbar-{sup 3}He drift tubes is described. The correlated scintillator and neutron-capture events provide a means for n/{gamma} discrimination, critical to the neutron calorimetry when the {gamma} background is substantial and the {gamma} signals are comparable in amplitude to the neutron signals. A single-cell prototype was constructed and tested. It can distinguish between a {sup 17}N source and a {sup 252}Cf source when the {gamma} and the thermal neutron background are sufficiently small. The design and construction of the nine-cell segmented detector assembly follow the same principle. By recording the signals from individual scintillators, additional {gamma}-subtraction schemes, such as through the time-of-flight between two scintillators, may also be used. The variations of the light outputs from different parts of a scintillator bar are less than 10%.

  6. Strong neutrino cooling by cycles of electron capture and ?- decay in neutron star crusts.

    PubMed

    Schatz, H; Gupta, S; Möller, P; Beard, M; Brown, E F; Deibel, A T; Gasques, L R; Hix, W R; Keek, L; Lau, R; Steiner, A W; Wiescher, M

    2014-01-01

    The temperature in the crust of an accreting neutron star, which comprises its outermost kilometre, is set by heating from nuclear reactions at large densities, neutrino cooling and heat transport from the interior. The heated crust has been thought to affect observable phenomena at shallower depths, such as thermonuclear bursts in the accreted envelope. Here we report that cycles of electron capture and its inverse, ?(-) decay, involving neutron-rich nuclei at a typical depth of about 150?metres, cool the outer neutron star crust by emitting neutrinos while also thermally decoupling the surface layers from the deeper crust. This 'Urca' mechanism has been studied in the context of white dwarfs and type Ia supernovae, but hitherto was not considered in neutron stars, because previous models computed the crust reactions using a zero-temperature approximation and assumed that only a single nuclear species was present at any given depth. The thermal decoupling means that X-ray bursts and other surface phenomena are largely independent of the strength of deep crustal heating. The unexpectedly short recurrence times, of the order of years, observed for very energetic thermonuclear superbursts are therefore not an indicator of a hot crust, but may point instead to an unknown local heating mechanism near the neutron star surface. PMID:24291788

  7. Strong neutrino cooling by cycles of electron capture and decay in neutron star crusts

    SciTech Connect

    Schatz, Hendrik [Michigan State University, East Lansing] [Michigan State University, East Lansing; Gupta, Sanjib [Indian Institute of Technology, Kanpur] [Indian Institute of Technology, Kanpur; Moeller, Peter [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Beard, Mary [University of Notre Dame, IN] [University of Notre Dame, IN; Brown, Edward [Michigan State University, East Lansing] [Michigan State University, East Lansing; Deibel, A. T. [Michigan State University, East Lansing] [Michigan State University, East Lansing; Gasques, Leandro [University of Sao Paulo, BRAZIL] [University of Sao Paulo, BRAZIL; Hix, William Raphael [ORNL] [ORNL; Keek, Laurens [Georgia Institute of Technology, Atlanta] [Georgia Institute of Technology, Atlanta; Lau, Rita [National Superconducting Cyclotron Laboratory (NSCL)] [National Superconducting Cyclotron Laboratory (NSCL); Steiner, Andrew M [University of Washington, Seattle] [University of Washington, Seattle; Wiescher, Michael [University of Notre Dame, IN] [University of Notre Dame, IN

    2013-01-01

    The temperature in the crust of an accreting neutron star, which comprises its outermost kilometre, is set by heating from nuclear reactions at large densities, neutrino cooling and heat transport from the interior. The heated crust has been thought to affect observable phenomena at shallower depths, such as thermonuclear bursts in the accreted envelope. Here we report that cycles of electron capture and its inverse, decay, involving neutron-rich nuclei at a typical depth of about 150 metres, cool the outer neutron star crust by emitting neutrinos while also thermally decoupling the surface layers from the deeper crust. This Urca mechanism has been studied in the context of white dwarfs13 and type Ia supernovae, but hitherto was not considered in neutron stars, because previous models1, 2 computed the crust reactions using a zero-temperature approximation and assumed that only a single nuclear species was present at any given depth. The thermal decoupling means that X-ray bursts and other surface phenomena are largely independent of the strength of deep crustal heating. The unexpectedly short recurrence times, of the order of years, observed for very energetic thermonuclear superbursts are therefore not an indicator of a hot crust, but may point instead to an unknown local heating mechanism near the neutron star surface.

  8. Neutron Capture Measurements on Minor Actinides at the n_TOF Facility at CERN: Past, Present and Future

    Microsoft Academic Search

    D. Cano-Ott; Paul Edward Koehler

    2011-01-01

    The successful development of advanced nuclear systems for sustainable energy production and nuclear waste management depends on high quality nuclear data libraries. Recent sensitivity studies and reports have identified the need for substantially improving the accuracy of neutron cross-section data for minor actinides. The n-TOF collaboration has initiated an ambitious experimental program for the measurement of neutron capture cross sections

  9. Neutron beam optimization for boron neutron capture therapy using the D-D and D-T high-energy neutron sources

    SciTech Connect

    Verbeke, J.M.; Vujic, J.L.; Leung, K.N.

    2000-02-01

    A monoenergetic neutron beam simulation study is carried out to determine the most suitable neutron energy for treatment of shallow and deep-seated brain tumors in the context of boron neutron capture therapy. Two figures-of-merit--the absorbed skin dose and the absorbed tumor dose at a given depth in the brain--are used to measure the neutron beam quality. Based on the results of this study, moderators, reflectors, and delimiters are designed and optimized to moderate the high-energy neutrons from the fusion reactions {sup 2}H(d,n){sup 3}He and {sup 3}H(d,n){sup 4}He down to a suitable energy spectrum. Two different computational models (MCNP and BNCT-RTPE) have been used to study the dose distribution in the brain. With the optimal beam-shaping assembly, a 1-A mixed deuteron/triton beam of energy 150 keV accelerated onto a titanium target leads to a treatment time of 1 h. The dose near the center of the brain obtained with this configuration is > 65% higher than the dose from a typical spectrum produced by the Brookhaven Medical Research Reactor and is comparable to the dose obtained by other accelerator-produced neutron beams.

  10. Comparative assessment of single-dose and fractionated boron neutron capture therapy

    SciTech Connect

    Coderre, J.A.; Micca, P.L.; Fisher, C.D. [Brookhaven National Laboratory, Upton, NY (United States)] [and others

    1995-12-01

    The effects of fractionating boron neutron capture therapy (BNCT) were evaluated in the intracerebral rat 9L gliosarcoma and rat spinal cord models using the Brookhaven Medical Research Reactor (BMRR) thermal neutron beam. The amino acid analog p-boronophenylalanine (BPA) was administered prior to each exposure to the thermal neutron beam. The total physical absorbed dose to the tumor during BNCT using BPA was 91% high-linear energy transfer (LET) radiation. Two tumor doses of 5.2 Gy spaced 48 h apart (n = 14) or three tumor doses of 5.2 Gy, each separated by 48 h (n = 10), produced 50 and 60% long-term (>1 year) survivors, respectively. The outcome of neither the two nor the three fractions of radiation was statistically different from that of the corresponding single-fraction group. In the rat spinal cord, the ED{sub 50} for radiation myelopathy (as indicated by limb paralysis within 7 months) after exposure to the thermal beam alone was 13.6 {+-} 0.4 Gy. Dividing the beam-only irradiation into two or four consecutive daily fractions increased the ED{sub 50} to 14.7 {+-} 0.2 Gy and 15.5 {+-} 0.4 Gy, respectively. Thermal neutron irradiation in the presence of BPA resulted in an ED{sub 50} for myelopathy of 13.8 {+-} 0.6 Gy after a single fraction and 14.9 {+-} 0.9 Gy after two fractions. An increase in the number of fractions to four resulted in an ED{sub 50} of 14.3 {+-} 0.6 Gy. The total physical absorbed dose to the blood in the vasculature of the spinal cord during BNCT using BPA was 80% high-LET radiation. It was observed that fractionation was of minor significance in the amelioration of damage to the normal central nervous system in the rat after boron neutron capture irradiation. 30 refs., 5 figs., 3 tabs.

  11. Optimization of Boron Neutron Capture Therapy for the Treatment of Undifferentiated Thyroid Cancer

    SciTech Connect

    Dagrosa, Maria Alejandra; Thomasz, Lisa M.Sc. [Department of Radiobiology (Constituyentes Atomic Center), National Atomic Energy Commission of Argentina, Buenos Aires (Argentina); Longhino, Juan [Nuclear Reactor RA-6 (Bariloche Atomic Center), National Atomic Energy Commission of Argentina, Buenos Aires (Argentina); Perona, Marina [Department of Radiobiology (Constituyentes Atomic Center), National Atomic Energy Commission of Argentina, Buenos Aires (Argentina); Calzetta, Osvaldo; Blaumann, Herman [Nuclear Reactor RA-6 (Bariloche Atomic Center), National Atomic Energy Commission of Argentina, Buenos Aires (Argentina); Rebagliati, Raul Jimenez [Department of Chemistry (Constituyentes Atomic Center), National Atomic Energy Commission of Argentina, Buenos Aires (Argentina); Cabrini, Romulo [Department of Radiobiology (Constituyentes Atomic Center), National Atomic Energy Commission of Argentina, Buenos Aires (Argentina); Kahl, Steven [Department of Pharmaceutical Chemistry, University of California, San Francisco, CA (United States); Juvenal, Guillermo Juan [Department of Radiobiology (Constituyentes Atomic Center), National Atomic Energy Commission of Argentina, Buenos Aires (Argentina); Pisarev, Mario Alberto [Department of Radiobiology (Constituyentes Atomic Center), National Atomic Energy Commission of Argentina, Buenos Aires (Argentina); Department of Human Biochemistry, School of Medicine, University of Buenos Aires, Buenos Aires (Argentina)], E-mail: pisarev@cnea.gov.ar

    2007-11-15

    Purpose: To analyze the possible increase in efficacy of boron neutron capture therapy (BNCT) for undifferentiated thyroid carcinoma (UTC) by using p-boronophenylalanine (BPA) plus 2,4-bis ({alpha},{beta}-dihydroxyethyl)-deutero-porphyrin IX (BOPP) and BPA plus nicotinamide (NA) as a radiosensitizer of the BNCT reaction. Methods and Materials: Nude mice were transplanted with a human UTC cell line (ARO), and after 15 days they were treated as follows: (1) control, (2) NCT (neutrons alone), (3) NCT plus NA (100 mg/kg body weight [bw]/day for 3 days), (4) BPA (350 mg/kg bw) + neutrons, (5) BPA + NA + neutrons, and (6) BPA + BOPP (60 mg/kg bw) + neutrons. The flux of the mixed (thermal + epithermal) neutron beam was 2.8 x 10{sup 8} n/cm{sup 2}/sec for 83.4 min. Results: Neutrons alone or with NA caused some tumor growth delay, whereas in the BPA, BPA + NA, and BPA + BOPP groups a 100% halt of tumor growth was observed in all mice at 26 days after irradiation. When the initial tumor volume was 50 mm{sup 3} or less, complete remission was found with BPA + NA (2 of 2 mice), BPA (1 of 4), and BPA + BOPP (7 of 7). After 90 days of complete regression, recurrence of the tumor was observed in BPA + NA (2 of 2) and BPA + BOPP (1 of 7). The determination of apoptosis in tumor samples by measurements of caspase-3 activity showed an increase in the BNCT (BPA + NA) group at 24 h (p < 0.05 vs. controls) and after the first week after irradiation in the three BNCT groups. Terminal transferase dUTP nick end labeling analysis confirmed these results. Conclusions: Although NA combined with BPA showed an increase of apoptosis at early times, only the group irradiated after the combined administration of BPA and BOPP showed a significantly improved therapeutic response.

  12. Boron containing macromolecules and nanovehicles as delivery agents for neutron capture therapy.

    PubMed

    Wu, Gong; Barth, Rolf F; Yang, Weilian; Lee, Robert J; Tjarks, Werner; Backer, Marina V; Backer, Joseph M

    2006-03-01

    Boron neutron capture therapy (BNCT) is based on the nuclear capture and fission reactions that occur when non-radioactive boron-10 is irradiated with low energy thermal neutrons to yield high linear energy transfer (LET) alpha particles ((4)He) and recoiling lithium -7((7)Li) nuclei. For BNCT to be successful, a sufficient number of (10)B atoms ( approximately 10(9) atoms/cell) must be selectively delivered to the tumor and enough thermal neutrons must be absorbed by them to sustain a lethal (10)B(n, alpha) (7)Li capture reaction. BNCT primarily has been used to treat patients with brain tumors, and more recently those with head and neck cancer. Two low molecular weight (LMW) boron delivery agents currently are being used clinically, sodium borocaptate and boronophenylalanine. However, a variety of high molecular weight (HMW) agents consisting of macromolecules and nanovehicles have been developed. This review will focus on the latter which include: monoclonal antibodies, dendrimers, liposomes, dextrans, polylysine, avidin, folic acid, and epidermal and vascular endothelial growth factors (EGF and VEGF). Procedures for introducing boron atoms into these HMW agents and their chemical properties will be discussed. In vivo studies on their biodistribution will be described, and the efficacy of a subset of them, which have been used for BNCT of tumors in experimental animals, will be discussed. Since brain tumors currently are the primary candidates for treatment by BNCT, delivery of these HMW agents across the blood-brain barrier presents a special challenge. Various routes of administration will be discussed including receptor-facilitated transcytosis following intravenous administration, direct intratumoral injection and convection enhanced delivery by which a pump is used to apply a pressure gradient to establish bulk flow of the HMW agent during interstitial infusion. Finally, we will conclude with a discussion relating to issues that must be addressed if these HMW agents are to be used clinically. PMID:16529539

  13. A Large-Scale Survey of Neutron-Capture Element Abundances in Planetary Nebulae

    E-print Network

    N. C. Sterling; Harriet L. Dinerstein; T. R. Kallman

    2007-08-09

    We present results from the first large-scale survey of neutron(n)-capture element abundances in planetary nebulae (PNe). This survey was motivated by the fact that a PN may be enriched in n-capture elements if its progenitor star experienced s-process nucleosynthesis during the asymptotic giant branch (AGB) phase. [Kr III] 2.199 and/or [Se IV] 2.287 $\\mu$m were detected in 81 PNe out of 120 PNe, for a detection rate of nearly 70%. We derive Se and Kr abundances or upper limits using ionization correction factors derived from photoionization models. A significant range is found in the Se and Kr abundances, from near solar (no enrichment), to enriched by a factor of ten. Our survey has increased the number of PNe with known n-capture element abundances by an order of magnitude, enabling us to explore correlations between s-process enrichments and other nebular and central star properties. In particular, the Se and Kr enrichments display a positive correlation with nebular C/O ratios, as theoretically expected. Peimbert Type I PNe and bipolar PNe, whose progenitors are believed to be intermediate-mass stars (>3-4 M_sun), exhibit little or no s-process enrichment. Interestingly, PNe with H-deficient [WC] central stars do not exhibit systematically larger s-process enrichments than other PNe, despite the fact that their central stars are enriched in C and probably n-capture elements. Finally, the few PNe in our sample with known or probable binary central star systems exhibit little s-process enrichment, which may be explained if binary interactions truncated their AGB phases. We also briefly discuss a new observational program to detect optical emission lines of n-capture elements, and new atomic data calculations that will greatly improve the accuracy of n-capture element abundance determinations in PNe.

  14. Boron Neutron Capture Therapy (BNCT) Dose Calculation using Geometrical Factors Spherical Interface for Glioblastoma Multiforme

    SciTech Connect

    Zasneda, Sabriani; Widita, Rena [Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha No. 10 Bandung, 40132 (Indonesia)

    2010-06-22

    Boron Neutron Capture Therapy (BNCT) is a cancer therapy by utilizing thermal neutron to produce alpha particles and lithium nuclei. The superiority of BNCT is that the radiation effects could be limited only for the tumor cells. BNCT radiation dose depends on the distribution of boron in the tumor. Absorbed dose to the cells from the reaction 10B (n, {alpha}) 7Li was calculated near interface medium containing boron and boron-free region. The method considers the contribution of the alpha particle and recoiled lithium particle to the absorbed dose and the variation of Linear Energy Transfer (LET) charged particles energy. Geometrical factor data of boron distribution for the spherical surface is used to calculate the energy absorbed in the tumor cells, brain and scalp for case Glioblastoma Multiforme. The result shows that the optimal dose in tumor is obtained for boron concentrations of 22.1 mg {sup 10}B/g blood.

  15. Description of the proton and neutron radiative capture reactions in the Gamow shell model

    E-print Network

    K. Fossez; N. Michel; M. P?oszajczak; Y. Jaganathen; R. M. Id Betan

    2015-02-10

    We formulate the Gamow shell model (GSM) in coupled-channel (CC) representation for the description of proton/neutron radiative capture reactions and present the first application of this new formalism for the calculation of cross-sections in mirror reactions 7Be(p,gamma)8B and 7Li(n,gamma)8Li. The GSM-CC formalism is applied to a translationally-invariant Hamiltonian with an effective finite-range two-body interaction. Reactions channels are built by GSM wave functions for the ground state 3/2- and the first excited state 1/2- of 7Be/7Li and the proton/neutron wave function expanded in different partial waves.

  16. Neutron capture cross section of unstable 63Ni: implications for stellar nucleosynthesis

    E-print Network

    C. Lederer; C. Massimi; S. Altstadt; J. Andrzejewski; L. Audouin; M. Barbagallo; V. Bécares; F. Bevá; F. Belloni; E. Berthoumieux; J. Billowes; V. Boccone; D. Bosnar; M. Brugger; M. Calviani; F. Calviño; D. Cano-Ott; C. Carrapiço; F. Cerutti; E. Chiaveri; M. Chin; N. Colonna; G. Cortés; M. A. Cortés-Giraldo; M. Diakaki; C. Domingo-Pardo; I. Duran; R. Dressler; N. Dzysiuk; C. Eleftheriadis; A. Ferrari; K. Fraval; S. Ganesan; A. R. García; G. Giubrone; M. B. Gómez-Hornillos; I. F. Gonçalves; E. González-Romero; E. Griesmayer; C. Guerrero; F. Gunsing; P. Gurusamy; D. G. Jenkins; E. Jericha; Y. Kadi; F. Käppeler; D. Karadimos; N. Kivel; P. Koehler; M. Kokkoris; G. Korschinek; M. Krtika; J. Kroll; C. Langer; H. Leeb; L. S. Leong; R. Losito; A. Manousos; J. Marganiec; T. Martínez; P. F. Mastinu; M. Mastromarco; M. Meaze; E. Mendoza; A. Mengoni; P. M. Milazzo; F. Mingrone; M. Mirea; W. Mondelaers; C. Paradela; A. Pavlik; J. Perkowski; M. Pignatari; A. Plompen; J. Praena; J. M. Quesada; T. Rauscher; R. Reifarth; A. Riego; F. Roman; C. Rubbia; R. Sarmento; P. Schillebeeckx; S. Schmidt; D. Schumann; G. Tagliente; J. L. Tain; D. Tarrío; L. Tassan-Got; A. Tsinganis; S. Valenta; G. Vannini; V. Variale; P. Vaz; A. Ventura; R. Versaci; M. J. Vermeulen; V. Vlachoudis; R. Vlastou; A. Wallner; T. Ware; M. Weigand; C. Weiß; T. J. Wright; P. Zugec

    2013-04-11

    The $^{63}$Ni($n, \\gamma$) cross section has been measured for the first time at the neutron time-of-flight facility n\\_TOF at CERN from thermal neutron energies up to 200 keV. In total, capture kernels of 12 (new) resonances were determined. Maxwellian Averaged Cross Sections were calculated for thermal energies from kT = 5 keV to 100 keV with uncertainties around 20%. Stellar model calculations for a 25 M$_\\odot$ star show that the new data have a significant effect on the $s$-process production of $^{63}$Cu, $^{64}$Ni, and $^{64}$Zn in massive stars, allowing stronger constraints on the Cu yields from explosive nucleosynthesis in the subsequent supernova.

  17. Neutron capture by (94,96)Zr and the decays of (97)Zr and (97)Nb.

    PubMed

    Krane, K S

    2014-12-01

    Cross sections for radiative neutron capture have been determined for (94)Zr and (96)Zr using the activation technique with samples of naturally occurring Zr metal. The sensitivity to the correction for epithermal neutrons in the determination of small thermal cross sections is discussed, particularly in view of the variation in the resonance integral at different sites in the reactor. Gamma-ray spectroscopic studies of the decays of (97)Zr and its daughter (97)Nb have been performed, leading to improved values of the energies and intensities of the emitted ? rays, and correspondingly improved values for the energy levels and ? feedings of excited states populated in (97)Nb and (97)Mo. PMID:25103250

  18. Study of characteristics for heavy water photoneutron source in boron neutron capture therapy

    E-print Network

    Salehi, Danial; Sardari, Dariush

    2013-01-01

    Bremsstrahlung photon beams produced by medical linear accelerators are currently the most commonly used method of radiation therapy for cancerous tumors. Photons with energies greater than 8-10 MeV potentially generate neutrons through photonuclear interactions in the accelerator's treatment head, patient's body, and treatment room ambient. Electrons impinging on a heavy target generate a cascade shower of bremsstrahlung photons, the energy spectrum of which shows an end point equal to the electron beam energy. By varying the target thickness, an optimum thickness exists for which, at the given electron energy, maximum photon flux is achievable. If a source of high-energy photons i.e. bremsstrahlung, is conveniently directed to a suitable D2O target, a novel approach for production of an acceptable flux of filterable photoneturons for boron neutron capture therapy (BNCT) application is possible. This study consists of two parts. 1. Comparison and assessment of deuterium photonuclear cross section data. 2. Ev...

  19. Synthesis and evaluation of boron compounds for neutron capture therapy of malignant brain tumors

    SciTech Connect

    Soloway, A.H.; Barth, R.F.

    1990-01-01

    Boron neutron capture therapy offers the potentiality for treating brain tumors currently resistant to treatment. The success of this form of therapy is directly dependent upon the delivery of sufficient numbers of thermal-neutrons to tumor cells which possess high concentrations of B-10. The objective of this project is to develop chemical methodology to synthesize boron-containing compounds with the potential for becoming incorporated into rapidly-dividing malignant brain tumor cells and excluded from normal components of the brain and surrounding tissues, to develope biological methods for assessing the potential of the compound by use of cell culture or intratumoral injection, to develop analytical methodology for measuring boron in cells and tissue using direct current plasma atomic emission spectroscopy (DCP-AES) and alpha track autoradiography, to develop biochemical and HPLC procedures for evaluating compound uptake and tissue half-life, and to develop procedures required to assess both in vitro and vivo efficacy of BNCT with selected compounds.

  20. Description of the proton and neutron radiative capture reactions in the Gamow shell model

    E-print Network

    Fossez, K; P?oszajczak, M; Jaganathen, Y

    2015-01-01

    We formulate the Gamow shell model (GSM) in coupled-channel (CC) representation for the description of proton/neutron radiative capture reactions and present the first application of this new formalism for the calculation of cross-sections in mirror reactions 7Be(p,gamma)8B and 7Li(n,gamma)8Li. The GSM-CC formalism is applied to a translationally-invariant Hamiltonian with an effective finite-range two-body interaction. Reactions channels are built by GSM wave functions for the ground state 3/2- and the first excited state 1/2- of 7Be/7Li and the proton/neutron wave function expanded in different partial waves.

  1. Computational study of the required dimensions for standard sized phantoms in boron neutron capture therapy dosimetry.

    PubMed

    Koivunoro, H; Auterinen, I; Kosunen, A; Kotiluoto, P; Seppälä, T; Savolainen, S

    2003-11-01

    The minimum size of a water phantom used for calibration of an epithermal neutron beam of the boron neutron capture therapy (BNCT) facility at the VTT FiR 1 research reactor is studied by Monte Carlo simulations. The criteria for the size of the phantom were established relative to the neutron and photon radiation fields present at the thermal neutron fluence maximum in the central beam axis (considered as the reference point). At the reference point, for the most commonly used beam aperture size at FiR 1 (14 cm diameter), less than 1% disturbance of the neutron and gamma radiation fields in a phantom were achieved with a minimum a 30 cm x 30 cm cross section of the phantom. For the largest 20 cm diameter beam aperture size, a minimum 40 cm x 40 cm cross-section of the phantom and depth of 20 cm was required to achieve undisturbed radiation field. This size can be considered as the minimum requirement for a reference phantom for dosimetry at FiR 1. The secondary objective was to determine the phantom dimensions for full characterization of the FiR 1 beam in a rectangular water phantom. In the water scanning phantom, isodoses down to the 5% level are measured for the verifications of the beam model in the dosimetric and treatment planning calculations. The dose distribution results without effects caused by the limited phantom size were achieved for the maximum aperture diameter (20 cm) with a 56 cm x 56 cm x 28 cm rectangular phantom. A similar approach to study the required minimum dimensions of the reference and water scanning phantoms can be used for epithermal neutron beams at the other BNCT facilities. PMID:14653569

  2. Single step synthesis of nanostructured boron nitride for boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Singh, Bikramjeet; Singh, Paviter; Kumar, Manjeet; Thakur, Anup; Kumar, Akshay

    2015-05-01

    Nanostructured Boron Nitride (BN) has been successfully synthesized by carbo-thermic reduction of Boric Acid (H3BO3). This method is a relatively low temperature synthesis route and it can be used for large scale production of nanostructured BN. The synthesized nanoparticles have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analyzer (DTA). XRD analysis confirmed the formation of single phase nanostructured Boron Nitride. SEM analysis showed that the particles are spherical in shape. DTA analysis showed that the phase is stable upto 900 °C and the material can be used for high temperature applications as well boron neutron capture therapy (BNCT).

  3. Tomographic image of prompt gamma ray from boron neutron capture therapy: A Monte Carlo simulation study

    SciTech Connect

    Yoon, Do-Kun; Jung, Joo-Young; Suk Suh, Tae, E-mail: suhsanta@catholic.ac.kr [Department of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, Catholic University of Korea, Seoul 505 (Korea, Republic of); Jo Hong, Key [Molecular Imaging Program at Stanford (MIPS), Department of Radiology, Stanford University, 300 Pasteur Drive, Stanford, California 94305 (United States)

    2014-02-24

    Purpose of paper is to confirm the feasibility of acquisition of three dimensional single photon emission computed tomography image from boron neutron capture therapy using Monte Carlo simulation. Prompt gamma ray (478?keV) was used to reconstruct image with ordered subsets expectation maximization method. From analysis of receiver operating characteristic curve, area under curve values of three boron regions were 0.738, 0.623, and 0.817. The differences between length of centers of two boron regions and distance of maximum count points were 0.3?cm, 1.6?cm, and 1.4?cm.

  4. First Stars VIII -- Enrichment of the neutron-capture elements in the early Galaxy

    E-print Network

    P. Francois; E. Depagne; V. Hill; M. Spite; F. Spite; B. Plez; T. C. Beers; J. Andersen; G. James; B. Barbuy; R. Cayrel; P. Bonifacio; P. Molaro; B. Nordström; F. Primas

    2007-09-21

    Our aim is to measure accurate, homogeneous neutron-capture element abundances for the sample of 32 EMP giant stars studied earlier in this series, including 22 stars with [Fe/H] $< -$3.0. Based on high-resolution, high S/N spectra from the ESO VLT/UVES, 1D, LTE model atmospheres, and synthetic spectrum fits, we determine abundances or upper limits for the 16 elements Sr, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, and Yb in all stars. As found earlier, [Sr/Fe], [Y/Fe], [Zr/Fe] and [Ba/Fe] are below Solar in the EMP stars, with very large scatter. However, we find a tight anti-correlation of [Sr/Ba], [Y/Ba], and [Zr/Ba] with [Ba/H] for $-4.5 <$ [Ba/H] $< -2.5$, also when subtracting the contribution of the main $r$-process as measured by [Ba/H]. The huge, well-characterised scatter of the [n-capture/Fe] ratios in our EMP stars is in stark contrast to the negligible dispersion in the [$\\alpha$/Fe] and [Fe-peak/Fe] ratios for the same stars found in Paper V. These results demonstrate that a second (``weak'' or LEPP) $r$-process dominates the production of the lighter neutron-capture elements for [Ba/H] $< -2.5$. The combination of very consistent [$\\alpha$/Fe] and erratic [n-capture/Fe] ratios indicates that inhomogeneous models for the early evolution of the halo are needed. Our accurate data provide strong constraints on future models of the production and mixing of the heavy elements in the early Galaxy.

  5. Boron neutron capture therapy of brain tumors: past history, current status, and future potential.

    PubMed

    Barth, R F; Soloway, A H; Brugger, R M

    1996-01-01

    Boron neutron capture therapy (BNCT) is based on the nuclear reaction that occurs when boron-10 is irradiated with low-energy thermal neutrons to yield alpha particles and recoiling lithium-7 nuclei. High-grade astrocytomas, glioblastoma multiforme, and metastatic brain tumors constitute a major group of neoplasms for which there is no effective treatment. There is growing interest in using BNCT in combination with surgery to treat patients with primary, and possibly metastatic brain tumors. For BNCT to be successful, a large number of 10B atoms must be localized on or preferably within neoplastic cells, and a sufficient number of thermal neutrons must reach and be absorbed by the 10B atoms to sustain a lethal 10B(n, alpha)7 Li reaction. Two major questions will be addressed in this review. First, how can a large number of 10B atoms be delivered selectively to cancer cells? Second, how can a high fluence of neutrons be delivered to the tumor? Two boron compounds currently are being used clinically, sodium borocaptate (BSH) and boronophenylalanine (BPA), and a number of new delivery agents are under investigation, including boronated porphyrins, nucleosides, amino acids, polyamines, monoclonal and bispecific antibodies, liposomes, and epidermal growth factor. These will be discussed, and potential problems associated with their use as boron delivery agents will be considered. Nuclear reactors, currently, are the only source of neutrons for BNCT, and the fission process within the core produces a mixture of lower-energy thermal and epithermal neutrons, fast or high (> 10,000 eV) energy neutrons, and gamma rays. Although thermal neutron beams have been used clinically in Japan to treat patients with brain tumors and cutaneous melanomas, epithermal neutron beams should be more useful because of their superior tissue-penetrating properties. Beam sources and characteristics will be discussed in the context of current and future BNCT trials. Finally, the past and present clinical trials on BNCT for brain tumors will be reviewed and the future potential of BNCT will be assessed. PMID:8951358

  6. Experimental assessment of the performance of a proposed lead slowing-down spectrometer at WNR/PSR (Weapons Neutron Research/Proton Storage Ring)

    SciTech Connect

    Moore, M.S.; Koehler, P.E.; Michaudon, A.; Schelberg, A. (Los Alamos National Lab., NM (USA)); Danon, Y.; Block, R.C.; Slovacek, R.E. (Rensselaer Polytechnic Inst., Troy, NY (USA)); Hoff, R.W.; Lougheed, R.W. (Lawrence Livermore National Lab., CA (USA))

    1990-01-01

    In November 1989, we carried out a measurement of the fission cross section of {sup 247}Cm, {sup 250}Cf, and {sup 254}Es on the Rensselaer Intense Neutron Source (RINS) at Rensselaer Polytechnic Institute (RPI). In July 1990, we carried out a second measurement, using the same fission chamber and electronics, in beam geometry at the Los Alamos Neutron Scattering Center (LANSCE) facility. Using the relative count rates observed in the two experiments, and the flux-enhancement factors determined by the RPI group for a lead slowing-down spectrometer compared to beam geometry, we can assess the performance of a spectrometer similar to RINS, driven by the Proton Storage Ring (PSR) at the Los Alamos National Laboratory. With such a spectrometer, we find that is is feasible to make measurements with samples of 1 ng for fission 1 {mu}g for capture, and of isotopes with half-lives of tens of minutes. It is important to note that, while a significant amount of information can be obtained from the low resolution RINS measurement, a definitive determination of average properties, including the level density, requires that the resonance structure be resolved. 12 refs., 5 figs., 3 tabs.

  7. Slow Neutron Cross Sections of Gold, Silver, Indium, Nickel, and Nickel Oxide

    Microsoft Academic Search

    R. G. Allen; T. E. Stephenson; C. P. Stanford; Seymour Bernstein

    1954-01-01

    The total reflection and selective attenuation properties of mirrors for neutrons were used to obtain essentially higher order free reflections of a beam of reactor neutrons from a quartz crystal. An arrangement of mirror, crystal, and sample, in series was used to measure the total cross section of Au, Ag, In, Ni, and NiO as a function of neutron wave

  8. Temperature dependence of the Westcott g-factor for neutron capture reactions in ENDF/B-VI

    SciTech Connect

    Holden, N.E.

    1993-08-01

    The Westcott g-factors, which allow the user to determine reaction rates for nuclear reactions taking place at various temperatures, have been calculated using data from the Evaluated Neutron Nuclear Data library, ENDF-VI. The nuclides chosen have g-factors which are significantly different from unity and result in different reaction rates compared to nuclides whose neutron capture cross section varies as the reciprocal of the neutron`s velocity. Values are presented as a function of temperature up to 400{degrees}C.

  9. Characterisation of neutron and gamma-ray emission from thick target Be(p,n) reaction for boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Guzek, J.; McMurray, W. R.; Mateva, T.; Franklyn, C. B.; Tapper, U. A. S.

    1998-04-01

    Low energy accelerator-based neutron sources have promising potential for use in a clinical treatment of cancer with boron neutron capture therapy (BNCT) and boron neutron capture synovectomy (BNCS). Such sources often utilise a thick target Be(p,n) reaction using incident proton energies from several hundred keV to 1-2 MeV above the reaction threshold of 2.06 MeV. The resulting neutron and gamma-ray beams require considerable moderation and filtration in order to obtain thermal and epithermal neutron fluxes for therapy. The detailed knowledge of neutron and gamma-ray spectra, yield and angular distribution are necessary in order to design effective moderators and filters to be used for the treatment. Thick and thin beryllium target neutron and gamma-ray spectra have been investigated in detail using the time-of-flight (TOF) technique, for incident proton energies from above threshold to 4 MeV. The results show characteristics of neutron and gamma-ray production of importance for the application of this neutron source for BNCT and BNCS.

  10. Boron neutron capture therapy of glioblastoma multiforme using the p- boronophenylalanine-fructose complex and epithermal neutrons

    SciTech Connect

    Coderre, J.A.; Chanana, A.D.; Joel, D.D.; Liu, H.B.; Slatkin, D.N.; Wielopolski, L. [Brookhaven National Lab., Upton, NY (United States); Bergland, R.; Elowitz, E. [Beth Israel Medical Center, New York, NY (United States). Dept. of Neurosurgery; Chadha, M. [Beth Israel Medical Center, New York, NY (United States). Dept. of Radiation Oncology

    1994-12-31

    The amino acid analogue p-boronophenylalanine (BPA) is under investigation as a neutron capture agent for BNCT of glioblastoma multiforme. A series of patients undergoing surgical removal of tumor received BPA orally as the free amino acid. Favorable tumor/blood boron concentration ratios were obtained but the absolute amount of boron in the tumor would have been insufficient for BNCT. BPA can be solubilized at neutral pH by complexation with fructose (BPA-F). Studies with rats suggest that intraperitoneal injection of BPA-F complex produces a much higher tumor boron concentration to rat intracerebral 9L gliosarcoma that were possible with oral BPA. Higher boron concentrations have allowed higher tumor radiation doses to be delivered while maintaining the dose to the normal brain vascular endothelium below the threshold of tolerance. The experience to date of the administration of BPA-F to one patient is provided in this report.

  11. Study of 194Ir via thermal neutron capture and (d,p) reactions .

    NASA Astrophysics Data System (ADS)

    Balodis, M.; Prokofjevs, P.; Kramere, N.; Simonova, L.; Berzins, J.; Krasta, T.; Georgii, R.; von Egidy, T.; Klora, J.; Lindner, H.; Mayerhofer, U.; Walter, A.; Cizewski, J. A.; Colvin, G. G.; Boerner, H. G.; Geltenbort, P.; Hoyler, F.; Kerr, S. A.; Schreckenbach, K.; Raemy, A.; Dousse, J. C.; Kern, J.; Schwitz, W.; Kondurov, I. A.; Loginov, Yu. E.; Sushkov, P. A.; Brant, S.; Paar, V.; Lopac, V.

    Levels of 194Ir were studied using thermal neutron capture reaction. A pair spectrometer was used to measure the high-energy g-ray spectrum from thermal-neutron capture in enriched 193Ir target over the energy range 4640 - 6100 keV. The low-energy g-radiation from the reaction was studied with crystal diffraction spectrometers, and conversion electrons were observed with magnetic spectrometers. The high-sensitivity measurements at the Grenoble reactor, evaluated for transition energies up to 500 keV, are compared with lower-sensitivity measurements at the Wuerenlingen and Salaspils reactors. The comparison helped to obtain reliable isotopic identification for a number of 194Ir lines. The multipolarity admixtures for 29 g-transitions were determined on the basis of conversion lines from different electron subshells. Prompt and delayed g-g coincidences were measured using semiconductor and scintillation detectors. The 193Ir(d,p) high-resolution spectra, observed with a magnetic spectrometer, are given. All these data contributed to establishing a detailed level scheme of 194Ir. Additional data and the interpretation of the results in terms of current models will be presented in a forthcoming paper.

  12. A stochastic model for subcellular dosimetry in boron neutron capture therapy.

    PubMed

    Ceberg, C P; Persson, A; Brun, A; Huiskamp, R; Salford, L G; Persson, B R

    1995-11-01

    The therapeutic effectiveness of boron neutron capture therapy is highly dependent on the microscopic distribution of the administered boron compound. Two boron compounds with different uptake mechanisms in the tumour cells may thus cause effects of different degrees even if the macroscopic boron concentrations in the tumour tissue are the same. This difference is normally expressed quantitatively by the so-called relative local efficiency (RLE). In this work, a stochastic model for the subcellular dosimetry has been developed. This model can be used to calculate the probability for an energy deposition above a certain threshold level in the cell nucleus due to a single neutron capture reaction. If a threshold cell-kill function is assumed, and if the dose is low enough that multiple energy depositions are rare, the model can also be applied to calculations of the survival probability for a cell population. Subcellular boron distributions in rats carrying RG 2 rat gliomas were measured by subcellular fractionation after administration of two different boron compounds: a sulphydryl boron hydride (BSH) and a boronated porphyrin (BOPP). Based on these data, the RLE factors were then calculated for these compounds using the stochastic model. PMID:8587934

  13. Hemorrhage in mouse tumors induced by dodecaborate cluster lipids intended for boron neutron capture therapy

    PubMed Central

    Schaffran, Tanja; Jiang, Nan; Bergmann, Markus; Küstermann, Ekkehard; Süss, Regine; Schubert, Rolf; Wagner, Franz M; Awad, Doaa; Gabel, Detlef

    2014-01-01

    The potential of boron-containing lipids with three different structures, which were intended for use in boron neutron capture therapy, was investigated. All three types of boron lipids contained the anionic dodecaborate cluster as the headgroup. Their effects on two different tumor models in mice following intravenous injection were tested; for this, liposomes with boron lipid, distearoyl phosphatidylcholine, and cholesterol as helper lipids, and containing a polyethylene glycol lipid for steric protection, were administered intravenously into tumor-bearing mice (C3H mice for SCCVII squamous cell carcinoma and BALB/c mice for CT26/WT colon carcinoma). With the exception of one lipid (B-THF-14), the lipids were well tolerated, and no other animal was lost due to systemic toxicity. The lipid which led to death was not found to be much more toxic in cell culture than the other boron lipids. All of the lipids that were well tolerated showed hemorrhage in both tumor models within a few hours after administration. The hemorrhage could be seen by in vivo magnetic resonance and histology, and was found to occur within a few hours. The degree of hemorrhage depended on the amount of boron administered and on the tumor model. The observed unwanted effect of the lipids precludes their use in boron neutron capture therapy. PMID:25114527

  14. Detector-Response Correction of Two-Dimensional ?-Ray Spectra from Neutron Capture

    NASA Astrophysics Data System (ADS)

    Rusev, G.; Jandel, M.; Arnold, C. W.; Bredeweg, T. A.; Couture, A.; Mosby, S. M.; Ullmann, J. L.

    2015-05-01

    The neutron-capture reaction produces a large variety of ?-ray cascades with different ?-ray multiplicities. A measured spectral distribution of these cascades for each ?-ray multiplicity is of importance to applications and studies of ?-ray statistical properties. The DANCE array, a 4? ball of 160 BaF2 detectors, is an ideal tool for measurement of neutron-capture ?-rays. The high granularity of DANCE enables measurements of high-multiplicity ?-ray cascades. The measured two-dimensional spectra (?-ray energy, ?-ray multiplicity) have to be corrected for the DANCE detector response in order to compare them with predictions of the statistical model or use them in applications. The detector-response correction problem becomes more difficult for a 4? detection system than for a single detector. A trial and error approach and an iterative decomposition of ?-ray multiplets, have been successfully applied to the detector-response correction. Applications of the decomposition methods are discussed for two-dimensional ?-ray spectra measured at DANCE from ?-ray sources and from the 10B(n, ?) and 113Cd(n, ?) reactions.

  15. The Impact of Updated Zr Neutron-capture Cross Sections and New Asymptotic Giant Branch Models on Our Understanding of the S Process and the Origin of Stardust

    NASA Astrophysics Data System (ADS)

    Lugaro, Maria; Tagliente, Giuseppe; Karakas, Amanda I.; Milazzo, Paolo M.; Käppeler, Franz; Davis, Andrew M.; Savina, Michael R.

    2014-01-01

    We present model predictions for the Zr isotopic ratios produced by slow neutron captures in C-rich asymptotic giant branch (AGB) stars of masses 1.25-4 M ? and metallicities Z = 0.01-0.03, and compare them to data from single meteoritic stardust silicon carbide (SiC) and high-density graphite grains that condensed in the outflows of these stars. We compare predictions produced using the Zr neutron-capture cross sections from Bao et al. and from n_TOF experiments at CERN, and present a new evaluation for the neutron-capture cross section of the unstable isotope 95Zr, the branching point leading to the production of 96Zr. The new cross sections generally present an improved match with the observational data, except for the 92Zr/94Zr ratios, which are on average still substantially higher than predicted. The 96Zr/94Zr ratios can be explained using our range of initial stellar masses, with the most 96Zr-depleted grains originating from AGB stars of masses 1.8-3 M ? and the others from either lower or higher masses. The 90, 91Zr/94Zr variations measured in the grains are well reproduced by the range of stellar metallicities considered here, which is the same needed to cover the Si composition of the grains produced by the chemical evolution of the Galaxy. The 92Zr/94Zr versus 29Si/28Si positive correlation observed in the available data suggests that stellar metallicity rather than rotation plays the major role in covering the 90, 91, 92Zr/94Zr spread.

  16. OCEAN: An ambitious experimental program for the qualification of integral capture cross sections of neutron absorbers

    SciTech Connect

    Hudelot, J. P.; Antony, M.; Bernard, D.; Leconte, P.; Testaniere, S.; Fougeras, P. [Commissariat a l'Energie Atomique, CEA/DEN Nuclear Energy Div., 13115 Saint-Paul-Lez-Durance Cedex (France)

    2006-07-01

    OCEAN (Oscillation in Core of Samples of Neutron Absorbers) is an ambitious experimental program supported by EDF and CEA. It is carried out in the MINERVE reactor of CEA Cadarache which is a low-power uranium fueled pool reactor. It started in 2005 and will end in 2008. It aims at improving the knowledge on nuclear basic data for the neutron absorbers. It deals at the same time with the improvement of the calculation tools and with the feasibility studies on the new options of the fuel cycle. It particularly supports, for the LWR reactors, the studies on the increase of the fuel cycle length in nuclear power plants, and on the plutonium management. It also aims at qualifying the calculation tools as regard with new neutron absorbers. The main framework is the European JEFF3 project. More in details, it deals with providing precise experimental data (capture cross sections) about the following absorbers: Gd-155, Gd-157, Gd-Nat, Hf-177, Hf-178, Hf-179, Hf-180, Er-166, Er-167, Er-168, Er-170, Dy-160, Dy-161, Dy-162, Dy-163, Dy-164, Eu-151, Eu-nat, and Eu-153. The study of the neutron absorbers is performed on a large range of neutron spectra (over-moderated thermal spectrum, PWR UOx standard spectrum, PWR 100% MOX spectrum and epithermal HCLWR type spectrum) corresponding respectively to the R2-UO{sub 2}, R1-UO{sub 2}, R1-MOX and MORGANE-R experimental lattices inside the MINERVE reactor. This paper first presents the objectives of the OCEAN experimental program. Then the description of the MINERVE facility is given, focusing on the different core configurations that will be studied, and the oscillation technique is reminded. Besides, the oscillation samples specially fabricated for the OCEAN program are described. Finally, the first preliminary experimental results in the R1-UO{sub 2} lattice are given and commented. (authors)

  17. Inertial electrostatic confinement: A unique compact accelerator-target source for neutron capture therapy

    SciTech Connect

    Miley, G.H. [Fusion Studies Lab., Urgana, IL (United States)

    1994-12-31

    The economic development of neutron capture therapy requires the availability of a compact, relatively inexpensive neutron source. A variety of accelerator-target concepts are considered competitors for this application, but all require considerable research and development to achieve the goals desired. In this presentation, a new concept is described, the Inertial Electrostatic Confinement or IEC device. The IEC is, in effect, an integrated ion-accelerator, plasma-target device. The use of a plasma-target removes the traditional target-heating issues, transferring heating to other components where it is more easily handled. A gaseous discharge in deuterium (or deuterium-tritium [D-T] mixtures) is developed between a spherical grid and the spherical vacuum-vessel wall. A high voltage applied to the grid not only creates the discharge, but also simultaneously extracts and focuses the ions into a small high-density volume at the center of the sphere where fusion occurs, producing neutrons. A high efficiency is obtained, since this creates a potential configuration which recirculates scattered ions through the dense center volume. Present experimental devices (30- to 60-cm diameter) at the U. of Illinois routinely produce 10{sup 6-7} 2.54-MeV D-D neutrons/sec steady-state/10{sup 8-9}u 14-MeV D-T n/s equivalent. Even higher neutron-emission rates have been achieved in a new pulsed version. As is, these devices are of interest for laboratory experiments, and a scaled-up version could be considered for human treatment. Concepts and issues related to scale-up will be presented.

  18. An Infrared Survey of Neutron-Capture Elements in Planetary Nebulae

    E-print Network

    N. C. Sterling; H. L. Dinerstein

    2004-08-25

    We present results from an ongoing survey of infrared emission lines from the neutron-capture elements Se and Kr in Galactic planetary nebulae (PNe). Se and Kr may be produced in the initial steps of the s-process during the asymptotic giant branch (AGB) phase of PN progenitor stars, and brought to the surface by convective dredge-up before PN ejection. Therefore, enriched Se and Kr abundances in PNe indicate that the s-process and dredge-up were active within the progenitor stars. We have detected the emission lines [Kr III] 2.199 and [Se IV] 2.287 microns in 68 of 119 Galactic PNe, and used these line fluxes to derive ionic and total elemental abundances. Using the ionization correction factors Se^{3+}/Se = Ar^{++}/Ar and Kr^{++}/Kr = S^{++}/S, we find a range of Se and Kr abundances, from nearly solar to enriched by a factor of 5-10 times, which implies varying degrees of dredge-up efficiency in the progenitor stars. We have searched for correlations between n-capture element abundances and other nebular properties, and find that PNe with Wolf-Rayet central stars tend to exhibit more elevated Se and Kr abundances than other nebulae. Bipolar nebulae, believed to arise from the most massive of PN progenitors, may have lower n-capture abundances than elliptical PNe.

  19. Stellar Neutron Capture on Promethium: Implications for the s-Process Neutron Density

    NASA Astrophysics Data System (ADS)

    Reifarth, R.; Arlandini, C.; Heil, M.; Käppeler, F.; Sedyshev, P. V.; Mengoni, A.; Herman, M.; Rauscher, T.; Gallino, R.; Travaglio, C.

    2003-01-01

    The unstable isotope 147Pm represents an important branch point in the s-process reaction path. This paper reports on the successful determination of the stellar (n, ?) cross section via the activation technique. The experiment was difficult because the relatively short 147Pm half-life of 2.62 yr enforced the sample mass to be restricted to 28 ng or 1014 atoms only. By means of a modular, high-efficiency Ge Clover array the low induced activity could be identified in spite of considerable backgrounds from various impurities. Both partial cross sections feeding the 5.37 day ground state and the 41.3 day isomer in 148Pm were determined independently, yielding a total (n, ?) cross section of 709+/-100 mbarn at a thermal energy of kT=30 keV. The (n, ?) cross sections of the additional branch point isotopes 147Nd and 148Pm as well as the effect of thermally excited states were obtained by detailed statistical model calculations. The present results allowed considerably refined analyses of the s-process branchings at A=147/148, which are probing the neutron density in the He-burning shell of low-mass asymptotic giant branch stars.

  20. Noble gas excimer scintillation following neutron capture in boron thin films

    E-print Network

    McComb, Jacob C; al-Sheikhly, Mohamed; Thompson, Alan K; Vest, Robert E; Clark, Charles W

    2014-01-01

    Far-ultraviolet (FUV) scintillation signals have been measured in heavy noble gases (argon, krypton, xenon) following boron-neutron capture ($^{10}$B($n,\\alpha$)$^7$Li) in $^{10}$B thin films. The observed scintillation yields are comparable to the yields from some liquid and solid neutron scintillators. At noble gas pressures of 10$^7$ kPa, the number of photons produced per neutron absorbed following irradiation of a 1200 nm thick $^{10}$B film was 14,000 for xenon, 11,000 for krypton, and 6000 for argon. The absolute scintillation yields from the experimental configuration were calculated using data from (1) experimental irradiations, (2) thin-film characterizations, (3) photomultiplier tube calibrations, and (4) photon collection modeling. Both the boron films and the photomultiplier tube were characterized at the National Institute of Standards and Technology. Monte Carlo modeling of the reaction cell provided estimates of the photon collection efficiency and the transport behavior of $^{10}$B($n,\\alpha$...

  1. Stellar neutron capture cross sections of Nd, Pm, and Sm isotopes

    SciTech Connect

    Toukan, K.A. (College of Engineering and Technology, The University of Jordan, Amman (Jordan)); Debus, K.; Kaeppeler, F. (Kernforschungszentrum Karlsruhe, Institut fuer Kernphysik, Postfach 3640 D-76021 Karlsruhe (Germany)); Reffo, G. (ENEA, Laboratorio Dati Nucleari, Viale Ercolani 8, I-40138 Bologna (Italy))

    1995-03-01

    The neutron capture cross sections of [sup 146,148,150]Nd have been determined relative to that of gold by means of the activation method. The samples were irradiated in a quasistellar neutron spectrum for [ital kT]=25 keV using the [sup 7]Li([ital p],[ital n])[sup 7]Be reaction near threshold. Variation of the experimental conditions in different activations and the use of different samples allowed for the reliable determination of corrections and the evaluation of systematic uncertainties. The resulting stellar cross sections can be given with uncertainties around 6%, which represents a considerable improvement compared to previous measurements. These data are complemented by a new set of calculated cross sections for the unstable isotopes [sup 147]Nd, [sup 147,148,149]Pm, and [sup 151]Sm, which act as branching points in the [ital s]-process path. Based on these results, the [ital s]-process flow in the Nd-Pm-Sm region is discussed with respect to the neutron density during stellar helium burning and to isotopic anomalies in meteorites. The updated [ital s]-abundances are also used for a discussion of [ital r]- and [ital p]-process residuals.

  2. Tetrakis(p-Carboranylthio-Tetrafluorophenyl)Chlorin (TPFC): Application for Photodynamic Therapy and Boron Neutron Capture Therapy

    PubMed Central

    HIRAMATSU, RYO; KAWABATA, SHINJI; TANAKA, HIROKI; SAKURAI, YOSHINORI; SUZUKI, MINORU; ONO, KOJI; MIYATAKE, SHIN-ICHI; KUROIWA, TOSHIHIKO; HAO, ERHONG; VICENTE, M. GRAÇA H.

    2015-01-01

    Carboranyl-containing chlorins have emerged as promising dual sensitizers for use in both photodynamic therapy (PDT) and boron neutron capture therapy (BNCT), by virtue of their known tumor affinity, low cytotoxicity in dark conditions, and their strong absorptions in the red region of the optical spectrum. Tetrakis(p-carboranylthio-tetrafluorophenyl)chlorin (TPFC) is a new synthetic carboranyl-containing chlorin of high boron content (24% by weight). To evaluate TPFC’s applicability as sensitizer for both PDT and BNCT, we performed an in vitro and in vivo study using F98 rat glioma cells and F98 rat glioma-bearing brain tumor models. For the in vivo BNCT study, we used boronophenylalanine (BPA), which is currently used in clinical BNCT studies, via intravenous administration (i.v.) and/or used TPFC via convection-enhanced delivery (CED), a method for local drug infusion directly into the brain. In the in vitro PDT study, the cell surviving fraction following laser irradiation (9 J/cm2) was 0.035 whereas in the in vitro BNCT study, the cell surviving fraction following neutron irradiation (thermal neutron = 1.73 × 1012 n/cm2) was 0.04. In the in vivo BNCT study, the median survival time following concomitant administration of BPA (i.v.) and TPFC (CED) was 42 days (95% confidence interval; 37–43 days). PMID:25546823

  3. Monte Carlo simulation of depth dose distribution in several organic models for boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Matsumoto, T.

    2007-09-01

    Monte Carlo simulations are performed to evaluate depth-dose distributions for possible treatment of cancers by boron neutron capture therapy (BNCT). The ICRU computational model of ADAM & EVA was used as a phantom to simulate tumors at a depth of 5 cm in central regions of the lungs, liver and pancreas. Tumors of the prostate and osteosarcoma were also centered at the depth of 4.5 and 2.5 cm in the phantom models. The epithermal neutron beam from a research reactor was the primary neutron source for the MCNP calculation of the depth-dose distributions in those cancer models. For brain tumor irradiations, the whole-body dose was also evaluated. The MCNP simulations suggested that a lethal dose of 50 Gy to the tumors can be achieved without reaching the tolerance dose of 25 Gy to normal tissue. The whole-body phantom calculations also showed that the BNCT could be applied for brain tumors without significant damage to whole-body organs.

  4. Measured microdosimetric spectra and therapeutic potential of boron neutron capture enhancement of 252Cf brachytherapy.

    PubMed

    Burmeister, J; Kota, C; Maughan, R L

    2005-09-01

    Californium-252 is a neutron-emitting radioisotope used as a brachytherapy source for radioresistant tumors. Presented here are microdosimetric spectra measured as a function of simulated site diameter and distance from applicator tube 252Cf sources. These spectra were measured using miniature tissue-equivalent proportional counters (TEPCs). An investigation of the clinical potential of boron neutron capture (BNC) enhancement of 252Cf brachytherapy is also provided. The absorbed dose from the BNC reaction was measured using a boron-loaded miniature TEPC. Measured neutron, photon and BNC absorbed dose components are provided as a function of distance from the source. In general, the absorbed dose results show good agreement with results from other measurement techniques. A concomitant boost to 252Cf brachytherapy may be provided through the use of the BNC reaction. The potential magnitude of this BNC enhancement increases with increasing distance from the source and is capable of providing a therapeutic gain greater than 30% at a distance of 5 cm from the source, assuming currently achievable boron concentrations. PMID:16137204

  5. Stellar neutron capture cross sections of Nd, Pm, and Sm isotopes

    NASA Astrophysics Data System (ADS)

    Toukan, K. A.; Debus, K.; Käppeler, F.; Reffo, G.

    1995-03-01

    The neutron capture cross sections of 146,148,150Nd have been determined relative to that of gold by means of the activation method. The samples were irradiated in a quasistellar neutron spectrum for kT=25 keV using the 7Li(p,n)7Be reaction near threshold. Variation of the experimental conditions in different activations and the use of different samples allowed for the reliable determination of corrections and the evaluation of systematic uncertainties. The resulting stellar cross sections can be given with uncertainties around 6%, which represents a considerable improvement compared to previous measurements. These data are complemented by a new set of calculated cross sections for the unstable isotopes 147Nd, 147,148,149Pm, and 151Sm, which act as branching points in the s-process path. Based on these results, the s-process flow in the Nd-Pm-Sm region is discussed with respect to the neutron density during stellar helium burning and to isotopic anomalies in meteorites. The updated s-abundances are also used for a discussion of r- and p-process residuals.

  6. Boron neutron capture therapy (BNCT) for liver metastasis: therapeutic efficacy in an experimental model

    SciTech Connect

    David W. Nigg

    2012-08-01

    Boron neutron capture therapy (BNCT) was proposed for untreatable colorectal liver metastases. The present study evaluates tumor control and potential radiotoxicity of BNCT in an experimental model of liver metastasis. BDIX rats were inoculated with syngeneic colon cancer cells DHD/K12/TRb. Tumor-bearing animals were divided into three groups: BPA–BNCT, boronophenylalanine (BPA) ? neutron irradiation; Beam only, neutron irradiation; Sham, matched manipulation. The total absorbed dose administered with BPA–BNCT was 13 ± 3 Gy in tumor and 9 ± 2 Gy in healthy liver. Three weeks posttreatment, the tumor surface area post-treatment/pre-treatment ratio was 0.46 ± 0.20 for BPA–BNCT, 2.7 ± 1.8 for Beam only and 4.5 ± 3.1 for Sham. The pre-treatment tumor nodule mass of 48 ± 19 mgfell significantly to 19 ± 16 mg for BPA–BNCT, but rose significantly to 140 ± 106 mg for Beam only and to 346 ± 302 mg for Sham. For both end points, the differences between the BPA–BNCT group and each of the other groups were statistically significant (ANOVA). No clinical, macroscopic or histological normal liver radiotoxicity was observed. It is concluded that BPA– BNCT induced a significant remission of experimental colorectal tumor nodules in liver with no contributory liver toxicity.

  7. Irradiation facility for boron neutron capture therapy application based on a rf-driven D-T neutron source and a new beam shaping assembly (abstract)

    NASA Astrophysics Data System (ADS)

    Cerullo, N.; Esposito, J.; Leung, K. N.

    2002-02-01

    Selecting the best neutron source for boron neutron capture therapy (BNCT) requires optimizing neutron beam parameters. This involves solving many complex problems. Safety issues related to the use of nuclear reactor in hospital environments, as well as lower costs have led to interest in the development of accelerator-driven neutron sources. The BNCT research programs at the Nuclear Departments of Pisa and Genova Universities (DIMNP and DITEC) focus on studies of new concepts for accelerator-based DT neutron sources. Simple and compact accelerator designs using relatively low deuteron beam energy, ˜100 keV, have been developed which, in turn, can generate high neutron yields. New studies have been started for optimization of moderator materials for the 14.1 MeV DT neutrons. Our aim is to obtain an epithermal neutron beam for therapeutic application at the exit end, with minimal beam intensity losses, the specific goal is to achieve an epithermal neutron flux of at least of 1×109 n/cm2 s at the beam port, with low gamma and fast neutron dose contamination. According to the most recent neutron BNCT beam parameters some moderating and spectrum shifter materials and geometrical configurations have thus far been tested, and neutron and gamma beam data at beam port have been computed. A possible beam shaping assembly model has been designed. This research demonstrates that a DT neutron source could be successfully implemented for BNCT application, with performance surpassing the minimum requirements stated above, using DT neutron sources with yields in the range 1013-1014 n/s. The latest Monte Carlo simulation results of an accelerator based facility which relies on a rf-driven DT fusion neutron generator will be presented.

  8. An irradiation facility for Boron Neutron Capture Therapy application based on a radio frequency driven DT neutron source and a new beam shaping assembly

    Microsoft Academic Search

    Nicola Cerullo; Juan Esposito; Ka Ngo Leung; Salvatore Custodero

    2002-01-01

    A line of the Boron Neutron Capture Therapy (BNCT) research program aimed at the treatment of brain tumors, carried on at the Nuclear Departments of Pisa and Genova Universities (DIMNP and DITEC), is being focused on a new, 3H(d,n)4He (D-T), accelerator-based neutron source concept, developed at Lawrence Berkeley National Laboratory (LBNL). Simple and compact accelerator designs, using mixed D+ T+

  9. Neutron radiative capture reactions on nuclei of relevance to 0???, dark matter and neutrino/antineutrino searches

    NASA Astrophysics Data System (ADS)

    Tornow, W.; Bhike, Megha

    2015-05-01

    A program is underway at the Triangle Universities Nuclear Laboratory (TUNL) to measure the neutron capture cross section in the 0.5 to 15 MeV energy range on nuclei whose radioactive daughters could potentially create backgrounds in searches for rare events. Here, we refer to neutrino-less double-beta decay and dark-matter searches, and to detectors built for neutrino and/or antineutrino studies. Neutron capture cross-section data obtained by using the activation method are reported for 40Ar, 74,76Ge, 128,130Te and 136Xe and compared to model calculations and evaluations.

  10. Determination of radiative neutron capture cross sections for unstable nuclei by the {gamma}-ray strength function method

    SciTech Connect

    Utsunomiya, H.; Goriely, S. [Department of Physics, Konan University, Okamoto 8-9-1, Higashinada, Kobe 658-8501 (Japan); Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles, Campus de la Plaine, CP-226, 1050 Brussels (Belgium)

    2012-11-12

    An indirect method referred to as the {gamma}-ray strength function method has been devised to determine radiative neutron capture cross sections for unstable nuclei along the valley of {beta}-stability. This method is based on the {gamma}-ray strength function which interconnects radiative neutron capture and photoneutron emission within the statistical model. The method was applied to several unstable nuclei such as {sup 93,95}Zr, {sup 107}Pd, and 121,123Sn. This method offers a versatile application extended to unstable nuclei far from the stability when combined with Coulomb dissociation experiments at RIKEN-RIBF and GSI.

  11. Noble gas excimer scintillation following neutron capture in boron thin films

    E-print Network

    Jacob C. McComb; Michael A. Coplan; Mohamed al-Sheikhly; Alan K. Thompson; Robert E. Vest; Charles W. Clark

    2014-03-24

    Far-ultraviolet (FUV) scintillation signals have been measured in heavy noble gases (argon, krypton, xenon) following boron-neutron capture ($^{10}$B($n,\\alpha$)$^7$Li) in $^{10}$B thin films. The observed scintillation yields are comparable to the yields from some liquid and solid neutron scintillators. At noble gas pressures of 107 kPa, the number of photons produced per neutron absorbed following irradiation of a 1200 nm thick $^{10}$B film was 14,000 for xenon, 11,000 for krypton, and 6000 for argon. The absolute scintillation yields from the experimental configuration were calculated using data from (1) experimental irradiations, (2) thin-film characterizations, (3) photomultiplier tube calibrations, and (4) photon collection modeling. Both the boron films and the photomultiplier tube were characterized at the National Institute of Standards and Technology. Monte Carlo modeling of the reaction cell provided estimates of the photon collection efficiency and the transport behavior of $^{10}$B($n,\\alpha$)$^7$Li reaction products escaping the thin films. Scintillation yields increased with gas pressure due to increased ionization and excitation densities of the gases from the $^{10}$B($n,\\alpha$)$^7$Li reaction products, increased frequency of three-body, excimer-forming collisions, and reduced photon emission volumes (i.e., larger solid angle) at higher pressures. Yields decreased for thicker $^{10}$B thin films due to higher average energy loss of the $^{10}$B($n,\\alpha$)$^7$Li reaction products escaping the films. The relative standard uncertainties in the measurements were determined to lie between 14 % and 16 %. The observed scintillation signal demonstrates that noble gas excimer scintillation is promising for use in practical neutron detectors.

  12. Parity violation in neutron-proton capture—The NPDGamma experiment

    NASA Astrophysics Data System (ADS)

    Gericke, Michael; Page, S.; Ramsay, D.; Alarcon, R.; Balascuta, S.; Barron, L.; Bowman, J. D.; Carlini, R. D.; Chen, W.; Chupp, T. E.; Crawford, C.; Covrig, S.; Dabaghyan, M.; Freedman, S. J.; Gentile, T. R.; Gillis, R. C.; Greene, G. L.; Hersman, F. W.; Ino, T.; Jones, G. L.; Lauss, B.; Leuschner, M.; Losowki, B.; Mahurin, R.; Masuda, Y.; Mei, J.; Mitchell, G. S.; Muto, S.; Nann, H.; Penttilä, S. I.; Salas-Bacci, A.; Santra, S.; Seo, P.-N.; Sharapov, E.; Sharma, M.; Smith, T.; Snow, W. M.; Wilburn, W. S.; Yuan, V.

    2009-12-01

    The NPDGamma collaboration has recently completed the first phase of a measurement to determine the size of the weak nucleon-nucleon interaction from cold neutron capture on a liquid hydrogen target. In the framework of the nearly 30 year old DDH model [B. Desplanques, J.F. Donoghue, B.R. Holstein, Annals of Physics 124 (1980) 449], the measured process is explained in terms of the weak pion-nucleon coupling, while the framework of modern effective field theory parameterizes the measured process in terms of the S13-P13, long range transition (essentially the Danilov parameter ?t) [S.L. Zhu et al., Nuclear Physics A 748 (2005) 435; C.-P. Liu, Phys. Rev. C 75 (2007) 065501]. The couplings in terms of either model are directly proportional to the parity violating up-down asymmetry in the angular distribution of gamma rays with respect to the neutron spin direction in the reaction n?+p?d+?. The asymmetry has a predicted size of 5×10-8 and the aim of the NPDGamma collaboration is to measure it to 20%. The first phase of the measurement was completed at the Los Alamos National Laboratory Neutron Science Center Spallation Source with a preliminary result of (-1.1±2.1 stat.±0.2 sys.)×10-7. Here, we report on the measurements and the results obtained so far. The experiment is currently being installed at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, for the remainder of its run time.

  13. Exploring Boron Neutron Capture Therapy for non-small cell lung cancer.

    PubMed

    Farías, Rubén O; Bortolussi, Silva; Menéndez, Pablo R; González, Sara J

    2014-12-01

    Boron Neutron Capture Therapy (BNCT) is a radiotherapy that combines biological targeting and high LET radiation. It consists in the enrichment of tumour with (10)B and in the successive irradiation of the target with low energy neutrons producing charged particles that mainly cause non-repairable damages to the cells. The feasibility to treat Non Small Cells Lung Cancer (NSCLC) with BNCT was explored. This paper proposes a new approach to determine treatment plans, introducing the possibility to choose the irradiation start and duration to maximize the tumour dose. A Tumour Control Probability (TCP) suited for lung BNCT as well as other high dose radiotherapy schemes was also introduced. Treatment plans were evaluated in localized and disseminated lung tumours. Semi-ideal and real energy spectra beams were employed to assess the best energy range and the performance of non-tailored neutron sources for lung tumour treatments. The optimal neutron energy is within [500 eV-3 keV], lower than the 10 keV suggested for the treatment of deep-seated tumours in the brain. TCPs higher than 0.6 and up to 0.95 are obtained for all cases. Conclusions drawn from [Suzuki et al., Int Canc Conf J 1 (4) (2012) 235-238] supporting the feasibility of BNCT for shallow lung tumours are confirmed, however discussions favouring the treatment of deeper lesions and disseminated disease are also opened. Since BNCT gives the possibility to deliver a safe and potentially effective treatment for NSCLC, it can be considered a suitable alternative for patients with few or no treatment options. PMID:25176019

  14. Radiobiology of boron neutron capture therapy: Problems with the concept of relative biological effectiveness

    SciTech Connect

    Coderre, J.A.; Makar, M.S.

    1990-01-01

    The radiation dose delivered to cells in vitro or vivo during boron neutron capture therapy (BNCT) is a mixture of photons, fast neutrons and heavy charged particles from the interaction of neutrons with nitrogen and born. The concept of relative biological effectiveness (RBE) had been developed to allow comparison of the effects of these radiations with the effects of standard photon treatments such as 250 kVp x-rays or {sup 60}Co gamma rays. The RBE value for all of these high linear energy transfer radiations can vary considerably depending upon the experimental conditions and endpoint utilized. The short range of the particles from the {sup 10}B(n,{alpha}) {sup 7}Li reaction make the precise subcellular location of the {sup 10}B atom of critical importance. The microscopic distribution of the {sup 10}B has a decided effect on the dosimetry. Monte Carlo simulations have shown that, at the cellular level, there is a profound difference in the probability of cell kill depending on the location of the {sup 10}B relative to the nucleus. Different boron-delivery agents will almost certainly have different distribution patterns at the subcellular level. The effect of BNCT with the amino acid p-boronophenylalanine (BPA) was compared with the effect of 250 kVp x-rays on a pigmented B16 melanoma subclone, both in vitro and in vivo. Generally accepted RBE values were applied to the relevant components of the Brookhaven Medical Research Reactor (BMRR) thermal neutron beam, however, there were still discrepancies when the resulting dose response curves were compared with the response to 250 kVp x-rays.

  15. Level structure of 89Sr investigated with thermal and fast neutron capture and the (d, p) reaction

    Microsoft Academic Search

    Ch. Winter; B. Krusche; K. P. Lieb; S. Michaelsen; G. Hlawatsch; H. Linder; T. von Egidy; F. Hoyler; R. F. Casten

    1989-01-01

    The gamma-ray spectrum emitted after thermal neutron capture in 88Sr was studied at the ILL high flux reactor with a pair-spectrometer and an intrinsic Ge detector. A total of 221 transitions were assigned to the decay 89Sr, and 55 of these, representing 55% of the observed flux, were placed in a level scheme of 19 states. The neutron binding energy

  16. Early clinical trial concept for boron neutron capture therapy: A critical assessment of the EORTC trial 11001

    Microsoft Academic Search

    A. Wittig; L. Collette; R. Moss; W. A. Sauerwein

    2009-01-01

    BNCT causes selective damage to tumor cells by neutron capture reactions releasing high LET-particles where 10B-atoms are present. Neither the 10B-compound nor thermal neutrons alone have any therapeutic effect. Therefore, the development of BNCT to a treatment modality needs strategies, which differ from the standard phase I–III clinical trials. An innovative trial design was developed including translational research and a

  17. Treatment planning and dosimetry for the Harvard-MIT Phase I clinical trial of cranial neutron capture therapy

    Microsoft Academic Search

    Matthew R. Palmer; J. Timothy Goorley; W. S. Kiger; Paul M. Busse; Kent J. Riley; Otto K. Harling; Robert G. Zamenhof

    2002-01-01

    Purpose: A Phase I trial of cranial neutron capture therapy (NCT) was conducted at Harvard-MIT. The trial was designed to determine maximum tolerated NCT radiation dose to normal brain.Methods and Materials: Twenty-two patients with brain tumors were treated by infusion of boronophenylalanine-fructose (BPA-f) followed by exposure to epithermal neutrons. The study began with a prescribed biologically weighted dose of 8.8

  18. The RPI multiplicity detector response to ?-ray cascades following neutron capture in 149 Sm and 150 Sm

    Microsoft Academic Search

    Shangwu Wang; M Lubert; Y Danon; N. C Francis; R. C. Block; F Be?vá?; M Krti?ka

    2003-01-01

    The response of the RPI 16-segment NaI(Tl) multiplicity detector system to the ?-rays following neutron radiative capture reactions is discussed. An algorithm which combines the Monte-Carlo ?-cascade code DICEBOX, based on the extreme statistical model, with the general MCNP(4C) Monte-Carlo particle transport computer program is presented. Two processes, the emission of the ?-cascades accompanying the individual events of the neutron

  19. Study of slow dynamics in supercooled water by molecular dynamics and quasi-elastic neutron scattering

    E-print Network

    Liu, Li, Ph. D. Massachusetts Institute of Technology

    2005-01-01

    The slow dynamics of supercooled water is studied by modelling the spectrum of test particle fluctuations: intermediate scattering function (ISF). The theoretical models are compared with experimental measurements by ...

  20. INVESTIGATION OF ROTATIONAL AND VIBRATIONAL FREEDOM IN MOLECULES BY CROSS SECTION MEASUREMENTS WITH SLOW NEUTRONS

    Microsoft Academic Search

    Rush

    1962-01-01

    Using a crystal spectrometer at the Brookhaven Reactor, total neutron ; cross sections have been obtained for a series to 2 ev. The compounds ; investigated include eight ammonium salts, ammonia gas, KHâPOâ, K\\/sub ; 2\\/HPOâ, and a series of liquid methylbenzenes. Cross sections were ; calculated from transmission measurements and were corrected for neutron ; absorption. Theoretical cross sections

  1. Critical evaluation of bispecific antibodies as targeting agents for boron neutron capture therapy of brain tumors.

    PubMed

    Liu, L; Barth, R F; Adams, D M; Soloway, A H; Reisfeld, R A

    1996-01-01

    Boron neutron capture therapy (BNCT) is based on the nuclear capture reaction that occurs when 10B, a stable isotope, is irradiated with low energy neutrons to produce high linear energy transfer (LET) alpha particles and recoiling 7Li nuclei. In order for BNCT to be successful in treating cancer, approximately 10(9) boron atoms must be delivered per tumor cell to sustain a lethal 10B, (n,a) 7Li capture reaction. In the present study, we have produced and characterized a bispecific antibody (BsAbB8), which was reactive with both human glioma and melanoma cell lines, as well as with a variety of polyhedral borane anions (PBA). The affinity constants (KA) of BsAb-B8 with D-54 MG and M21 cells were 3.49 and 2.57 x 10(8) M-1, respectively, which were almost identical to those of the parental mAb 9.2.27 with these cell lines. In vivo tumor localizing properties were studied in nude mice bearing subcutaneous xenografts of the D-54 MG glioma. Following intravenous injection of 131I-labeled BsAb-B8, 3.4 +/- 0.2% of the injected dose/g was detected in the tumor at 24 hours, and then slowly declined to 2.0 +/- 0.4% at 96 hours compared to 1.34 +/- 0.07% and 0.03 +/- 0.01%, respectively, for normal mouse IgG. Based on the assumption that all the tumor cell antigenic receptor sites could be saturated, the following calculations have been carried out. The maximum concentration of BsAb-B8 that could be delivered to 1 g of D-54 MG glioma cells would be 99.6 micrograms, which could bind 71.7 ng of a PBA. However, since at least 500 x more boron would be required per gram of tumor to sustain a lethal 10B (n,a) 7Li capture reaction, a macromolecule containing -10(3)-10(4) boron atoms rather than a low molecular weight PBA would be required to deliver this amount. Such boron containing macromolecules have been synthesized by us, and future studies should provide information on the feasibility of using them in combination with BsAb-B8 to deliver the requisite amount of 10B. PMID:8917355

  2. Development and in vitro studies of epidermal growth factor-dextran conjugates for boron neutron capture therapy.

    PubMed

    Gedda, L; Olsson, P; Pontén, J; Carlsson, J

    1996-01-01

    A delivery molecule for directed boron neutron capture therapy against epidermal growth factor (EGF) receptor-rich tumors, such as gliomas, squamous carcinomas, and breast cancers, is presented. EGF and sulfhydryl boron hydride (BSH) were covalently coupled to an allylated 70 kDa dextran chain to form a conjugate. Conjugates with low and high substitution rates of BSH, as well as without BSH, were investigated. The conjugate with a low amount of boron had approximately 6 BSH (72 boron atoms) per dextran, while the conjugates with higher amounts had an average substitution of 55 BSH (660 boron atoms) per dextran. The maximum substitution of boron to dextran in a single experiment was over 800 boron atoms. Binding, retention, and internalization of 125I-labeled conjugates were investigated on cultured human glioma cells. Binding of the conjugates was EGF receptor specific, but the amount of BSH coupled to dextran affected specificity, more than the presence of dextran. The nonspecific binding of the conjugates increased with the amount of attached boron. This was partly due to nonspecific adhesion to the plastic in the culture dishes. [125I]EGF-allyldextran with 6 BSH had a binding maximum after 4 h of continuous incubation and thereafter decreased in binding, while [125I]EGF-allyldextran with the higher substitution rate had a slow increase of binding during 24 h. Over 93% of the radioactivity bound to the cells was internalized, but the retention was quite poor. Only one-third of the cell-bound activity was still associated to the cells 4 h after incubation had ended. In conclusion, it is possible to load the conjugates produced with high amounts of boron, and they retained specificity for the EGF receptor and internalized into cultured cells. Theoretical calculations show that about 10(3) boron atoms per EGF-based conjugate are needed to give a satisfactory therapeutic response. These conjugates are within reach of that level. PMID:8889021

  3. Mixed-field dosimetry measurement of a target assembly for an accelerator-based neutron source for boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Reed, M. K.; Dobelbower, M. C.; Woollard, J. E.; Blue, T. E.

    1998-12-01

    The objective of this work was to measure the neutron and gamma-ray absorbed dose components for a target assembly for an Accelerator-Based Neutron Source (ABNS) for Boron Neutron Capture Therapy (BNCT), and to compare these measurements with MCNP calculations in order to verify the calculations of the in-air neutron and gamma-ray absorbed dose components. The measurements were made using the paired ionization chamber technique. The measured neutron and gamma-ray specific absorbed dose components agreed with calculations within experimental errors, which were approximately 10%. The measured gamma-ray specific absorbed dose rate of 140 cGy s -1 A -1 ±12% is consistent with reported yields of 478 keV gamma rays due to the 7Li(p, p') 7Li * reaction. This specific gamma absorbed dose rate is significant and should not be neglected in moderator assembly design.

  4. Radiative-neutron-capture gamma-ray analysis by a linear combination technique

    USGS Publications Warehouse

    Tanner, A.B.; Bhargava, R.C.; Senftle, F.E.; Brinkerhoff, J.M.

    1972-01-01

    The linear combination technique, when applied to a gamma-ray spectrum, gives a single number indicative of the extent to which the spectral lines of a sought element are present in a complex spectrum. Spectra are taken of the sought element and of various other substances whose spectra interfere with that of the sought element. A weighting function is then computed for application to spectra of unknown materials. The technique was used to determine calcium by radiative-neutron-capture gamma-ray analysis in the presence of interfering elements, notably titanium, and the results were compared with those for two popular methods of peak area integration. Although linearity of response was similar for the methods, the linear combination technique was much better at rejecting interferences. For analyses involving mixtures of unknown composition the technique consequently offers improved sensitivity. ?? 1972.

  5. First Measurement of ?_13 from Delayed Neutron Capture on Hydrogen in the Double Chooz Experiment

    E-print Network

    Double Chooz Collaboration; Y. Abe; C. Aberle; J. C. dos Anjos; J. C. Barriere; M. Bergevin; A. Bernstein; T. J. C. Bezerra; L. Bezrukhov; E. Blucher; N. S. Bowden; C. Buck; J. Busenitz; A. Cabrera; E. Caden; L. Camilleri; R. Carr; M. Cerrada; P. -J. Chang; P. Chimenti; T. Classen; A. P. Collin; E. Conover; J. M. Conrad; J. I. Crespo-Anadón; K. Crum; A. Cucoanes; E. Damon; J. V. Dawson; S. Dazeley; D. Dietrich; Z. Djurcic; M. Dracos; V. Durand; J. Ebert; Y. Efremenko; M. Elnimr; A. Erickson; A. Etenko; M. Fallot; M. Fechner; F. von Feilitzsch; J. Felde; S. M. Fernandes; V. Fischer; D. Franco; A. J. Franke; M. Franke; H. Furuta; R. Gama; I. Gil-Botella; L. Giot; M. Göger-Neff; L. F. G. Gonzalez; L. Goodenough; M. C. Goodman; J. TM. Goon; D. Greiner; N. Haag; S. Habib; C. Hagner; T. Hara; F. X. Hartmann; J. Haser; A. Hatzikoutelis; T. Hayakawa; M. Hofmann; G. A. Horton-Smith; A. Hourlier; M. Ishitsuka; J. Jochum; C. Jollet; C. L. Jones; F. Kaether; L. N. Kalousis; Y. Kamyshkov; D. M. Kaplan; T. Kawasaki; G. Keefer; E. Kemp; H. de Kerret; T. Konno; D. Kryn; M. Kuze; T. Lachenmaier; C. E. Lane; C. Langbrandtner; T. Lasserre; A. Letourneau; D. Lhuillier; H. P. Lima Jr; M. Lindner; J. M. López-Castaño; J. M. LoSecco; B. K. Lubsandorzhiev; S. Lucht; D. McKee; J. Maeda; C. N. Maesano; C. Mariani; J. Maricic; J. Martino; T. Matsubara; G. Mention; A. Meregaglia; M. Meyer; T. Miletic; R. Milincic; H. Miyata; Th. A. Mueller; Y. Nagasaka; K. Nakajima; P. Novella; M. Obolensky; L. Oberauer; A. Onillon; A. Osborn; I. Ostrovskiy; C. Palomares; I. M. Pepe; S. Perasso; P. Perrin; P. Pfahler; A. Porta; W. Potzel; G. Pronost; J. Reichenbacher; B. Reinhold; A. Remoto; M. Röhling; R. Roncin; S. Roth; B. Rybolt; Y. Sakamoto; R. Santorelli; F. Sato; S. Schönert; S. Schoppmann; T. Schwetz; M. H. Shaevitz; S. Shimojima; D. Shrestha; J-L. Sida; V. Sinev; M. Skorokhvatov; E. Smith; J. Spitz; A. Stahl; I. Stancu; L. F. F. Stokes; M. Strait; A. Stüken; F. Suekane; S. Sukhotin; T. Sumiyoshi; Y. Sun; R. Svoboda; K. Terao; A. Tonazzo; M. Toups; H. H. Trinh Thi; G. Valdiviesso; C. Veyssiere; S. Wagner; H. Watanabe; B. White; C. Wiebusch; L. Winslow; M. Worcester; M. Wurm; F. Yermia; V. Zimmer

    2013-08-29

    The Double Chooz experiment has determined the value of the neutrino oscillation parameter $\\theta_{13}$ from an analysis of inverse beta decay interactions with neutron capture on hydrogen. This analysis uses a three times larger fiducial volume than the standard Double Chooz assessment, which is restricted to a region doped with gadolinium (Gd), yielding an exposure of 113.1 GW-ton-years. The data sample used in this analysis is distinct from that of the Gd analysis, and the systematic uncertainties are also largely independent, with some exceptions, such as the reactor neutrino flux prediction. A combined rate- and energy-dependent fit finds $\\sin^2 2\\theta_{13}=0.097\\pm 0.034(stat.) \\pm 0.034 (syst.)$, excluding the no-oscillation hypothesis at 2.0 \\sigma. This result is consistent with previous measurements of $\\sin^2 2\\theta_{13}$.

  6. Are There Any Stars Lacking Neutron-Capture Elements? Evidence from Strontium and Barium

    E-print Network

    Roederer, Ian U

    2012-01-01

    The cosmic dispersion in the abundances of the heavy elements strontium and barium in halo stars is well known. Strontium and barium are detected in most cool, metal-poor giants, but are these elements always detectable? To identify stars that could be considered probable candidates for lacking these elements, I examine the stellar abundance data available in the literature for 1148 field stars and 226 stars in dwarf galaxies, 776 of which have metallicities lower than [Fe/H]Strontium or barium have been detected in all field, globular cluster, and dwarf galaxy environments studied. All upper limits are consistent with the lowest detected ratios of [Sr/H] and [Ba/H]. The frequent appearance of these elements raises the intriguing prospect that at least one kind of neutron-capture reaction operates as often as the nucleosynthesis mechanisms that produce lighter elements, like magnesium, calcium, or iron, although the yields of heavy elements may be more variable.

  7. Bispecific antibodies as targeting agents for boron neutron capture therapy of brain tumors.

    PubMed

    Liu, L; Barth, R F; Adams, D M; Soloway, A H; Reisfeld, R A

    1995-10-01

    Boron neutron capture therapy (BNCT) is based on the nuclear reaction that occurs when boron-10, a stable isotope, is irradiated with low energy (< or = 0.025 eV) or thermal neutrons to yield alpha particles and recoiling lithium-7 nuclei. A major requirement for the success of BNCT is the selective delivery of a sufficient number of boron atoms (approximately 10(9)) to individual cancer cells to sustain a lethal 10B (n, alpha) 7Li capture reaction. A panel of BsAb reactive with polyhedral borane anions (PBA) and a tumor-associated chondroitin sulfate proteoglycan has been produced. All of these BsAb showed strong reactivity with a panel of human glioblastoma and melanoma cell lines, as demonstrated by indirect membrane immunofluorescence. Two of them (H6 and B8) also reacted with cells that had been exposed to PBA (Na2B10H10 and Na2B12H11SH) and a boronated starburst dendrimer, which contained approximately 250-400 B atoms per molecule. The affinity constant (Ka) of BsAb-B8 was 2.57 x 10(8) M-1 on M21 human melanoma cell and 3.49 x 10(8) M-1 on A172 glioblastoma cells, which were almost identical to those of the parental monoclonal antibody (mAb) 9.2.27 on the same cell lines (2.62 x 10(8) M-1). Since our BsAb recognize both human glioblastoma and melanoma-associated antigens, as well as PBA, they potentially could be used to target 10B to these tumors for BNCT. PMID:8581388

  8. Boron Neutron Capture Therapy in the Treatment of Locally Recurred Head and Neck Cancer

    SciTech Connect

    Kankaanranta, Leena [Department of Oncology, Helsinki University Central Hospital, Helsinki (Finland); Seppaelae, Tiina; Koivunoro, Hanna [Department of Physical Sciences, University of Helsinki, Helsinki (Finland); Boneca Corporation Ltd (Finland); Saarilahti, Kauko [Department of Oncology, Helsinki University Central Hospital, Helsinki (Finland); Atula, Timo [Department of Otorhinolaryngology, Helsinki University Central Hospital, Helsinki (Finland); Collan, Juhani [Department of Oncology, Helsinki University Central Hospital, Helsinki (Finland); Salli, Eero; Kortesniemi, Mika [HUS Medical Imaging Center, Helsinki University Central Hospital, Helsinki (Finland); Uusi-Simola, Jouni [Department of Physical Sciences, University of Helsinki, Helsinki (Finland); HUS Medical Imaging Center, Helsinki University Central Hospital, Helsinki (Finland); Maekitie, Antti [Department of Otorhinolaryngology, Helsinki University Central Hospital, Helsinki (Finland); Seppaenen, Marko [Turku PET Centre, Turku University Hospital, Turku (Finland); Minn, Heikki [Department of Oncology, Turku University Hospital, Turku (Finland); Kotiluoto, Petri; Auterinen, Iiro [VTT Technical Research Centre of Finland, Espoo (Finland); Savolainen, Sauli [Department of Physical Sciences, University of Helsinki, Helsinki (Finland); HUS Medical Imaging Center, Helsinki University Central Hospital, Helsinki (Finland); Kouri, Mauri [Department of Oncology, Helsinki University Central Hospital, Helsinki (Finland); Joensuu, Heikki [Department of Oncology, Helsinki University Central Hospital, Helsinki (Finland)], E-mail: heikki.joensuu@hus.fi

    2007-10-01

    Purpose: Head and neck carcinomas that recur locally after conventional irradiation pose a difficult therapeutic problem. We evaluated safety and efficacy of boron neutron capture therapy (BNCT) in the treatment of such cancers. Methods and Materials: Twelve patients with inoperable, recurred, locally advanced (rT3, rT4, or rN2) head and neck cancer were treated with BNCT in a prospective, single-center Phase I-II study. Prior treatments consisted of surgery and conventionally fractionated photon irradiation to a cumulative dose of 56-74 Gy administered with or without concomitant chemotherapy. Tumor responses were assessed using the RECIST (Response Evaluation Criteria in Solid Tumors) criteria and adverse effects using the National Cancer Institute common toxicity grading v3.0. Intravenously administered boronophenylalanine-fructose (BPA-F, 400 mg/kg) was used as the boron carrier. Each patient was scheduled to be treated twice with BNCT. Results: Ten patients received BNCT twice; 2 were treated once. Ten (83%) patients responded to BNCT, and 2 (17%) had tumor growth stabilization for 5.5 and 7.6 months. The median duration of response was 12.1 months; six responses were ongoing at the time of analysis or death (range, 4.9-19.2 months). Four (33%) patients were alive without recurrence with a median follow-up of 14.0 months (range, 12.8-19.2 months). The most common acute adverse effects were mucositis, fatigue, and local pain; 2 patients had a severe (Grade 3) late adverse effect (xerostomia, 1; dysphagia, 1). Conclusions: Boron neutron capture therapy is effective and safe in the treatment of inoperable, locally advanced head and neck carcinomas that recur at previously irradiated sites.

  9. A new analytical formula for neutron capture gamma dose calculations in double-bend mazes in radiation therapy

    PubMed Central

    Ghiasi, Hosein; Mesbahi, Asghar

    2012-01-01

    Background Photoneutrons are produced in radiation therapy with high energy photons. Also, capture gamma rays are the byproduct of neutrons interactions with wall material of radiotherapy rooms. Aim In the current study an analytical formula was proposed for capture gamma dose calculations in double bend mazes in radiation therapy rooms. Materials and methods A total of 40 different layouts with double-bend mazes and a 18 MeV photon beam of Varian 2100 Clinac were simulated using MCNPX Monte Carlo (MC) code. Neutron capture gamma ray dose equivalent was calculated by the MC method along the maze and at the maze entrance door of all the simulated rooms. Then, all MC resulted data were fitted to an empirical formula for capture gamma dose calculations. Wu–McGinley analytical formula for capture gamma dose equivalent at the maze entrance door in single-bend mazes was also used for comparison purposes. Results For capture gamma dose equivalents at the maze entrance door, the difference of 2–11% was seen between MC and the derived equation, while the difference of 36–87% was found between MC and the Wu–McGinley methods. Conclusion Our results showed that the derived formula results were consistent with the MC results for all of 40 different geometries. However, as a new formula, further evaluations are required to validate its use in practical situations. Finally, its application is recommend for capture gamma dose calculations in double-bend mazes to improve shielding calculations. PMID:24377027

  10. Resonance capture by hydrogenous impurities and losses of ultracold neutrons in solid material traps

    E-print Network

    G. S. Danilov

    2009-03-03

    The capture of trapped ultracold neutrons (UCNs) by closed hydrogenous impurities within a solid coating of the trap is discussed as a possible cause of observed anomalously large losses of UCNs in solid material UCN traps. Then significant losses of UCNs arise only if resonances occur in the UCN-impurity scattering amplitude. For a large size impurity, higher partial waves in the UCN-impurity interaction are important, and they are taken into account in the present paper. The method of the calculation is applicable to irregular shape impurities as well. A small distortion of an impurity shape, if it splits the resonance, can increase the UCN losses by a few times. UCN losses in the beryllium trap are calculated assuming they are due to the UCN capture by ice spherical impurities within the coating of the trap walls. Both s- and p-wave resonances contribute significantly to the UCN losses considered. As an example, observed anomalous large UCN losses are achieved if the average radius of the impurity is about 600 Angstroms and the impurity density is about 3*10^{14}/cm^3. A distortion of the spherical shape of the impurity could increase the UCN losses and therefore decrease the impurity density.

  11. Dynamic infrared imaging for biological and medical applications in Boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Santa Cruz, Gustavo A.; González, Sara J.; Dagrosa, Alejandra; Schwint, Amanda E.; Carpano, Marina; Trivillin, Verónica A.; Boggio, Esteban F.; Bertotti, José; Marín, Julio; Monti Hughes, Andrea; Molinari, Ana J.; Albero, Miguel

    2011-05-01

    Boron Neutron Capture Therapy (BNCT) is a treatment modality, currently focused on the treatment of cancer, which involves a tumor selective 10B compound and a specially tuned neutron beam to produce a lethal nuclear reaction. BNCT kills target cells with microscopic selectivity while sparing normal tissues from potentially lethal doses of radiation. In the context of the Argentine clinical and research BNCT projects at the National Atomic Energy Commission and in a strong collaboration with INVAP SE, we successfully implemented Dynamic Infrared Imaging (DIRI) in the clinical setting for the observation of cutaneous melanoma patients and included DIRI as a non invasive methodology in several research protocols involving small animals. We were able to characterize melanoma lesions in terms of temperature and temperature rate-of-recovery after applying a mild cold thermal stress, distinguishing melanoma from other skin pigmented lesions. We observed a spatial and temporal correlation between skin acute reactions after irradiation, the temperature pattern and the dose distribution. We studied temperature distribution as a function of tumor growth in mouse xenografts, observing a significant correlation between tumor temperature and drug uptake; we investigated temperature evolution in the limbs of Wistar rats for a protocol of induced rheumatoid arthritis (RA), DIRI being especially sensitive to RA induction even before the development of clinical signs and studied surface characteristics of tumors, precancerous and normal tissues in a model of oral cancer in the hamster cheek pouch.

  12. Electron-capture delayed fission properties of neutron-deficient einsteinium nuclei

    SciTech Connect

    Shaughnessy, Dawn A.

    2000-01-05

    Electron-capture delayed fission (ECDF) properties of neutron-deficient einsteinium isotopes were investigated using a combination of chemical separations and on-line radiation detection methods. {sup 242}Es was produced via the {sup 233}U({sup 14}N,5n){sup 242}Es reaction at a beam energy of 87 MeV (on target) in the lab system, and was found to decay with a half-life of 11 {+-} 3 seconds. The ECDF of {sup 242}Es showed a highly asymmetric mass distribution with an average pre-neutron emission total kinetic energy (TKE) of 183 {+-} 18 MeV. The probability of delayed fission (P{sub DF}) was measured to be 0.006 {+-} 0.002. In conjunction with this experiment, the excitation functions of the {sup 233}U({sup 14}N,xn){sup 247{minus}x}Es and {sup 233}U({sup 15}N,xn){sup 248{minus}x}Es reactions were measured for {sup 243}Es, {sup 244}Es and {sup 245}Es at projectile energies between 80 MeV and 100 MeV.

  13. Characteristics of a heavy water photoneutron source in boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Danial, Salehi; Dariush, Sardari; M. Salehi, Jozani

    2013-07-01

    Bremsstrahlung photon beams produced by medical linear accelerators are currently the most commonly used method of radiation therapy for cancerous tumors. Photons with energies greater than 8-10 MeV potentially generate neutrons through photonuclear interactions in the accelerator's treatment head, patient's body, and treatment room ambient. Electrons impinging on a heavy target generate a cascade shower of bremsstrahlung photons, the energy spectrum of which shows an end point equal to the electron beam energy. By varying the target thickness, an optimum thickness exists for which, at the given electron energy, maximum photon flux is achievable. If a source of high-energy photons i.e. bremsstrahlung, is conveniently directed to a suitable D2O target, a novel approach for production of an acceptable flux of filterable photoneturons for boron neutron capture therapy (BNCT) application is possible. This study consists of two parts. 1. Comparison and assessment of deuterium photonuclear cross section data. 2. Evaluation of the heavy water photonuclear source.

  14. Stellar neutron capture cross sections of 20,21,22Ne

    NASA Astrophysics Data System (ADS)

    Heil, M.; Plag, R.; Uberseder, E.; Gallino, R.; Bisterzo, S.; Juseviciute, A.; Käppeler, F.; Lederer, C.; Mengoni, A.; Pignatari, M.

    2014-10-01

    The stellar (n ,? ) cross sections of the Ne isotopes are important for a number of astrophysical quests, i.e., for the interpretation of abundance patterns in presolar material or with respect to the s -process neutron balance in red giant stars. This paper presents resonance studies of experimental data in the keV range, which had not been fully analyzed before. The analyses were carried out with the R -matrix code sammy. With these results for the resonant part and by adding the components due to direct radiative capture, improved Maxwellian-averaged cross sections (MACS) could be determined. At k T =30 keV thermal energy we obtain MACS values of 240 ±29 ,1263 ±160 , and 53.2 ±2.7 ? barn for 20Ne>, 21Ne, and 22Ne, respectively. In earlier work the stellar rates of 20Ne and 21Ne had been grossly overestimated. 22Ne and 20Ne are significant neutron poisons for the s process in stars because their very small MACS values are compensated by their large abundances.

  15. GAMMA RAYS FROM MAJOR ELEMENTS BY THERMAL NEUTRON CAPTURE REACTIONS: EXPERIMENT AND SIMULATION FOR PLANETARY GAMMA-RAY SPECTROSCOPY.

    E-print Network

    Berezhnoi, Aleksei A.

    GAMMA RAYS FROM MAJOR ELEMENTS BY THERMAL NEUTRON CAPTURE REACTIONS: EXPERIMENT AND SIMULATION FOR PLANETARY GAMMA-RAY SPECTROSCOPY. N. Yamashita1 , N. Hasebe1 , M. -N. Kobayashi1 , T. Miyachi1 , O. Okudaira of planetary surface can be determined by remotely measuring the energies and intensities of gamma rays

  16. Demonstration of three-dimensional deterministic radiation transport theory dose distribution analysis for boron neutron capture therapy

    Microsoft Academic Search

    David W. Nigg; P. D. Randolph; F. J. Wheeler

    1991-01-01

    The Monte Carlo stochastic simulation technique has traditionally been the only well-recognized method for computing three-dimensional radiation dose distributions in connection with boron neutron capture therapy (BNCT) research. A deterministic approach to this problem would offer some advantages over the Monte Carlo method. This paper describes an application of a deterministic method to analytically simulate BNCT treatment of a canine

  17. Astrophysical reaction rates for Ni-58,Ni-60(n,gamma) from new neutron capture cross section measurements

    SciTech Connect

    Guber, Klaus H [ORNL; Derrien, Herve [ORNL; Leal, Luiz C [ORNL; Arbanas, Goran [ORNL; Wiarda, Dorothea [ORNL; Koehler, Paul [ORNL; Harvey, John A [ORNL

    2010-01-01

    New neutron capture cross section of 58,60Ni were measured in the energy range from 100 eV to 600 keV using the Oak Ridge Electron Linear Accelerator (ORELA). The combination of these new neutron capture data with previous transmission data allowed a resonance analysis up to 900 keV using R-matrix theory. The theoretically determined direct capture (DC) cross sections were included in the analyses. From these resonance parameters and the DC contribution, new (n,y) astrophysical reaction rates were determined over the entire energy range needed by the lastest stellar models describing the so-called weak s process. PACS numbers: 25.40.Lw, 26.20Kn, 27.40.+z, 27.50.+e, 97.10.Cv

  18. A Monte Carlo model for on-line neutron capture prompt gamma-ray analysis of coal in transmission geometry

    SciTech Connect

    Yuan, Y.L.; Gardner, R.P.; Verghese, K.

    1987-04-01

    A Monte Carlo simulation model has been developed to predict the unscattered gamma-ray intensities of an in situ neutron capture prompt gamma-ray analysis system for assaying the elemental concentrations of material that move on a conveyor belt. The model incorporates all pertinent neutron and photon interactions for the assay of coal and all variance reduction techniques necessary to make every history a success. Prompt gamma-ray intensities from all elements of interest over a range of elemental compositions of the sample matrix are calculated in one execution of the program. The calculated results are verified with experimental results on a coal sample in a test configuration that is spiked with variable amounts of sulfur and titanium as two sample elements of interest. The model is expected to be very useful for the optimum design and calibration of on-line neutron capture prompt gamma-ray analysis systems operating in the conveyor belt geometry.

  19. Opportunities afforded by the intense nanosecond neutron pulses from a plasma focus source for neutron capture therapy and the preliminary simulation results

    NASA Astrophysics Data System (ADS)

    Giannini, G.; Gribkov, V.; Longo, F.; Ramos Aruca, M.; Tuniz, C.

    2012-11-01

    The use of short and powerful neutron pulses for boron neutron capture therapy (BNCT) can potentially increase selectivity and reduce the total dose absorbed by the patient. The biological effects of radiation depend on the dose, the dose power and the spatial distribution of the microscopic energy deposition. A dense plasma focus (DPF) device emits very short (in the nanosecond range) and extremely intense pulses of fast neutrons (2.5 or 14 MeV neutrons—from D-D or D-T nuclear reactions) and x-rays. Optimal spectra of neutrons formed for use in BNCT must contain an epithermal part to ensure a reasonable penetration depth into tissues at high enough cross-section on boron. So the powerful nanosecond pulses of fast neutrons generated by DPF must be moderated. After this moderation, the pulse duration must be shorter compared with the duration of the reaction with free radicals, that is, ?1 ?s. In this work we focus on the development of a detailed simulation of interaction of short-pulse radiation from a DPF with the device's materials and with different types of moderators to estimate the dose power at the cells for this dynamic case. The simulation was carried out by means of the Geant4 toolkit in two main steps: the modeling of the pulsed neutron source device itself; the study of the interaction of fast mono-energetic neutrons with a moderator specific for BNCT.

  20. Design, construction, and characterization of a facility for neutron capture gamma ray analysis of sulfur in coal using californium-252

    SciTech Connect

    Layfield, J.R.

    1980-03-01

    A study of neutron capture gamma ray analysis of sulfur in coal using californium-252 as a neutron source is reported. Both internal and external target geometries are investigated. The facility designed for and used in this study is described. The external target geometry is found to be inappropriate because of the low thermal neutron flux at the sample location, which must be outside the biological shielding. The internal target geometry is found to have a sufficient thermal neutron flux, but an excessive gamma ray background. A water filled plastic facility, rather than the paraffin filled steel one used in this study, is suggested as a means of increasing flexibility and decreasing the beackground in the internal target geometry.

  1. Monte Carlo assessment of soil moisture effect on high-energy thermal neutron capture gamma-ray by 14N.

    PubMed

    Pazirandeh, Ali; Azizi, Maryam; Farhad Masoudi, S

    2006-01-01

    Among many conventional techniques, nuclear techniques have shown to be faster, more reliable, and more effective in detecting explosives. In the present work, neutrons from a 5 Ci Am-Be neutron source being in water tank are captured by elements of soil and landmine (TNT), namely (14)N, H, C, and O. The prompt capture gamma-ray spectrum taken by a NaI (Tl) scintillation detector indicates the characteristic photo peaks of the elements in soil and landmine. In the high-energy region of the gamma-ray spectrum, besides 10.829 MeV of (15)N, single escape (SE) and double escape (DE) peaks are unmistakable photo peaks, which make the detection of concealed explosive possible. The soil has the property of moderating neutrons as well as diffusing the thermal neutron flux. Among many elements in soil, silicon is more abundant and (29)Si emits 10.607 MeV prompt capture gamma-ray, which makes 10.829 MeV detection difficult. The Monte Carlo simulation was used to adjust source-target-detector distances and soil moisture content to yield the best result. Therefore, we applied MCNP4C for configuration very close to reality of a hidden landmine in soil. PMID:16081298

  2. The Abundances of Light Neutron-Capture Elements in Planetary Nebulae

    E-print Network

    N. C. Sterling; Harriet L. Dinerstein

    2006-05-02

    We present preliminary results from a large-scale survey of the neutron(n)-capture elements Se and Kr in Galactic planetary nebulae (PNe). These elements may be produced in PN progenitors by s-process nucleosynthesis, and brought to the stellar envelope by third dredge-up (TDU). We have searched for [Kr III] 2.199 and [Se IV] 2.287 $\\mu$m in 120 PNe, and detected one or both lines in 79 objects, for a detection rate of 66%. In order to determine abundances of Se and Kr, we have added these elements to the atomic database of the photoionization code CLOUDY, and constructed a large grid of models to derive corrections for unobserved ionization stages. Se and Kr are enriched in 73% of the PNe in which they have been detected, and exhibit a wide range of abundances, from roughly solar to enriched by a factor of 10 or more. These enrichments are interpreted as evidence for the operation of the s-process and TDU in the progenitor stars. In line with theoretical expectations, Kr is more strongly enhanced than Se, and the abundances of both elements are correlated with the carbon abundance. Kr and Se are strongly enhanced in Type I PNe, which may be evidence for the operation of the $^{22}$Ne neutron source in intermediate-mass AGB stars. These results constitute the first broad characterization of s-process enrichments in PNe as a population, and reveal the impact of low- and intermediate-mass stars on the chemical evolution of trans-iron elements in the Galaxy.

  3. Gadolinium incorporated reconstituted chylomicron emulsion for potential application in tumor neutron capture therapy.

    PubMed

    Dierling, Annie M; Sloat, Brian R; Cui, Zhengrong

    2006-04-01

    Gadolinium (Gd) neutron capture therapy (NCT) is currently under development as a potential approach for tumor therapy. Nanoparticles have been suggested as a potential delivery system to carry or target Gd to tumors for thermal or epithermal neutron irradiation. The reconstituted chylomicron emulsion is an artificial chylomicron remnant prepared using commercially available natural and biocompatible lipids. We proposed to use this nanometer-scale emulsion to deliver Gd to solid tumors by modifying the surface of the emulsion. A lipophilic Gd compound, gadolinium acetylacetonate (GdAcAc), was incorporated into the emulsion, resulting in a final pure Gd concentration of more than 1 mg/mL. The apparent solubility of GdAcAc was enhanced by about 6000-fold by this incorporation. The emulsion particles were shown to be stable in a two-week short-term stability study when stored at 4 degrees C. In addition, no extensive particle aggregation was observed when the emulsion particles were incubated in simulated biological media such as serum. Also, GdAcAc does not significantly 'leak' out from the emulsion particles. Only approximately 5% was released in 20 h in a SDS (0.5% w/v) in phosphate buffered saline (pH 7.4, 10 mM) medium. Finally, the emulsion particles were coated with polyethylene glycol (PEG), and injected into Balb/C mice via the tail vein. A significant proportion (71.6 +/- 18.4%) of the PEG-coated, GdAcAc-incorporated emulsion remained circulating in the blood 5 h after the injection, while the PEG-free emulsion was mainly accumulated inside the liver. This chylomicron emulsion may be used to deliver Gd into solid tumors for NCT. PMID:16274979

  4. Macroscopic geometric heterogeneity effects in radiation dose distribution analysis for boron neutron capture therapy.

    PubMed

    Moran, J M; Nigg, D W; Wheeler, F J; Bauer, W F

    1992-01-01

    Calculations of radiation flux and dose distributions for boron neutron capture therapy (BNCT) of brain tumors are typically performed using sophisticated three-dimensional analytical models based on either a homogeneous approximation or a simplified few-region approximation to the actual highly heterogeneous geometry of the irradiation volume. Such models should be validated by comparison with calculations using detailed models in which all significant macroscopic tissue heterogeneities and geometric structures are explicitly represented as faithfully as possible. This paper describes such a validation exercise for BNCT of canine brain tumors. Geometric measurements of the canine anatomical structures of interest for this work were performed by dissecting and examining two essentially identical Labrador retriever heads. Chemical analyses of various tissue samples taken during the dissections were conducted to obtain measurements of elemental compositions for the tissues of interest. The resulting geometry and tissue composition data were then used to construct a detailed heterogeneous calculational model of the Labrador head. Calculations of three-dimensional radiation flux distributions pertinent to BNCT were performed for this model using the TORT discrete-ordinates radiation transport code. The calculations were repeated for a corresponding volume-weighted homogeneous-tissue model. Comparison of the results showed that peak neutron and photon flux magnitudes were quite similar for the two models (within 5%), but that the spatial flux profiles were shifted in the heterogeneous model such that the fluxes in some locations away from the peak differed from the corresponding fluxes in the homogeneous model by as much as 10%-20%. Differences of this magnitude can be therapeutically significant, emphasizing the need for proper validation of simplified treatment planning models. PMID:1508112

  5. Macroscopic geometric heterogeneity effects in radiation dose distribution analysis for boron neutron capture therapy

    SciTech Connect

    Moran, J.M.; Nigg, D.W.; Wheeler, F.J.; Bauer, W.F. (Idaho National Engineering Laboratory, EG G Idaho, Inc., P.O. Box 1625, Idaho Falls, Idaho 83415-3515 (United States))

    1992-05-01

    Calculations of radiation flux and dose distributions for boron neutron capture therapy (BNCT) of brain tumors are typically performed using sophisticated three-dimensional analytical models based on either a homogeneous approximation or a simplified few-region approximation to the actual highly heterogeneous geometry of the irradiation volume. Such models should be validated by comparison with calculations using detailed models in which all significant macroscopic tissue heterogeneities and geometric structures are explicitly represented as faithfully as possible. This paper describes such a validation exercise for BNCT of canine brain tumors. Geometric measurements of the canine anatomical structures of interest for this work were performed by dissecting and examining two essentially identical Labrador retriever heads. Chemical analyses of various tissue samples taken during the dissections were conducted to obtain measurements of elemental compositions for the tissues of interest. The resulting geometry and tissue composition data were then used to construct a detailed heterogeneous calculational model of the Labrador head. Calculations of three-dimensional radiation flux distributions pertinent to BNCT were performed for this model using the TORT discrete-ordinates radiation transport code. The calculations were repeated for a corresponding volume-weighted homogeneous-tissue model. Comparison of the results showed that peak neutron and photon flux magnitudes were quite similar for the two models (within 5%), but that the spatial flux profiles were shifted in the heterogeneous model such that the fluxes in some locations away from the peak differed from the corresponding fluxes in the homogeneous model by as much as 10%--20%. Differences of this magnitude can be therapeutically significant, emphasizing the need for proper validation of simplified treatment planning models.

  6. Effect of bevacizumab combined with boron neutron capture therapy on local tumor response and lung metastasis

    PubMed Central

    MASUNAGA, SHIN-ICHIRO; SAKURAI, YOSHINORI; TANO, KEIZO; TANAKA, HIROKI; SUZUKI, MINORU; KONDO, NATSUKO; NARABAYASHI, MASARU; WATANABE, TSUBASA; NAKAGAWA, YOSUKE; MARUHASHI, AKIRA; ONO, KOJI

    2014-01-01

    The aim of the present study was to evaluate the effect of bevacizumab on local tumor response and lung metastatic potential during boron neutron capture therapy (BNCT) and in particular, the response of intratumor quiescent (Q) cells. B16-BL6 melanoma tumor-bearing C57BL/6 mice were continuously administered bromodeoxyuridine (BrdU) to label all proliferating (P) tumor cells. The tumors were irradiated with thermal neutron beams following the administration of a 10B-carrier [L-para-boronophenylalanine-10B (BPA) or sodium mercaptoundecahydrododecaborate-10B (BSH)], with or without the administration of bevacizumab. This was further combined with an acute hypoxia-releasing agent (nicotinamide) or mild temperature hyperthermia (MTH, 40°C for 60 min). Immediately following the irradiation, cells from certain tumors were isolated and incubated with a cytokinesis blocker. The responses of the Q cells and the total (P+Q) cell populations were assessed based on the frequency of micronuclei using immunofluorescence staining for BrdU. In other tumor-bearing mice, 17 days following irradiation, lung metastases were enumerated. Three days following bevacizumab administration, the sensitivity of the total tumor cell population following BPA-BNCT had increased more than that following BSH-BNCT. The combination with MTH, but not with nicotinamide, further enhanced total tumor cell population sensitivity. Regardless of the presence of a 10B-carrier, MTH enhanced the sensitivity of the Q cell population. Regardless of irradiation, the administration of bevacizumab, as well as nicotinamide treatment, demonstrated certain potential in reducing the number of lung metastases especially in BPA-BNCT compared with BSH-BNCT. Thus, the current study revealed that BNCT combined with bevacizumab has the potential to sensitize total tumor cells and cause a reduction in the number of lung metastases to a similar level as nicotinamide. PMID:24944637

  7. Fission fragment mass and energy distributions as a function of incident neutron energy measured in a lead slowing-down spectrometer

    Microsoft Academic Search

    C. Romano; Y. Danon; R. Block; J. Thompson; E. Blain; E. Bond

    2010-01-01

    A new method of measuring fission fragment mass and energy distributions as a function of incident neutron energy in the range from below 0.1 eV to 1 keV has been developed. The method involves placing a double-sided Frisch-gridded fission chamber in Rensselaer Polytechnic Institute's lead slowing-down spectrometer (LSDS). The high neutron flux of the LSDS allows for the measurement of

  8. The Radiative Neutron Capture on 2H, 6Li, 7Li, 12C AND 13C at Astrophysical Energies

    NASA Astrophysics Data System (ADS)

    Dubovichenko, Sergey; Dzhazairov-Kakhramanov, Albert; Burkova, Natalia

    2013-05-01

    The continued interest in the study of radiative neutron capture on atomic nuclei is due, on the one hand, to the important role played by this process in the analysis of many fundamental properties of nuclei and nuclear reactions, and, on the other hand, to the wide use of the capture cross-section data in the various applications of nuclear physics and nuclear astrophysics, and, also, to the importance of the analysis of primordial nucleosynthesis in the Universe. This paper is devoted to the description of results for the processes of the radiative neutron capture on certain light atomic nuclei at thermal and astrophysical energies. The consideration of these processes is done within the framework of the potential cluster model (PCM), general description of which was given earlier. The methods of usage of the results obtained, based on the phase shift analysis intercluster potentials, are demonstrated in calculations of the radiative capture characteristics. The considered capture reactions are not part of stellar thermonuclear cycles, but involve in the basic reaction chain of primordial nucleosynthesis in the course of the Universe formation.

  9. A Novel Method of Boron Delivery Using Sodium Iodide Symporter for Boron Neutron Capture Therapy

    PubMed Central

    KUMAR, Sanath; FREYTAG, Svend O.; BARTON, Kenneth N.; BURMEISTER, Jay; JOINER, Michael C.; SEDGHI, Bijan; MOVSAS, Benjamin; BINNS, Peter J.; KIM, Jae Ho; BROWN, Stephen L.

    2013-01-01

    Boron Neutron Capture Therapy (BNCT) effectiveness depends on the preferential sequestration of boron in cancer cells relative to normal tissue cells. We present a novel strategy for sequestering boron using an adenovirus expressing the sodium iodide symporter (NIS). Human glioma grown subcutaneously in athymic mice and orthotopic rat brain tumors were transfected with NIS using a direct tumor injection of adenovirus. Boron bound as sodium tetrafluoroborate (NaBF4) was administered systemically several days after transfection. Tumors were excised hours later and assessed for boron concentration using inductively coupled plasma atomic emission spectroscopy. In the human glioma transfected with NIS, boron concentration was more than 10 fold higher with 100 mg/kg of NaBF4, compared to tumor not transfected. In the orthotopic tumor model, the presence of NIS conferred almost 4 times the boron concentration in rat tumors transfected with human virus compared with contralateral normal brain not transfected. We conclude that adenovirus expressing NIS has the potential to be used as a novel boron delivery agent and should be explored for future clinical applications. PMID:20921830

  10. Methods for radiation dose distribution analysis and treatment planning in boron neutron capture therapy.

    PubMed

    Nigg, D W

    1994-03-30

    This article presents a survey of recent progress in the development and application of analytical methods for calculating macroscopic and microscopic radiation dose distributions for Boron Neutron Capture Therapy (BNCT). Such calculations are an essential component of in vivo BNCT research and will ultimately also be required for human BNCT treatment planning. Calculations of macroscopic absorbed dose distributions for BNCT are more complex than for photon therapy. There are several different dose components, each of which has its own characteristic spatial distribution, linear energy transfer, and relative biological effectiveness (RBE). Three-dimensional (3-D) energy-dependent radiation transport models with a detailed treatment of particle scattering are required. Geometric descriptions for such models are typically constructed directly from medical image data and both the Monte Carlo stochastic simulation method and the discrete-ordinates deterministic approach have been successfully used to perform the necessary radiation transport calculations. Microdosimetric effects can profoundly influence the therapeutic benefit that may be attainable in BNCT. These effects must be carefully taken into account in the interpretation of experimental data, especially when correlating observed in vivo radiobiological response with absorbed radiation dose. Calculations of microdosimetric parameters for BNCT are typically performed using the Monte Carlo method to generate single-event energy deposition frequency distributions for critical targets in various cell types of interest. This information is useful in the development of apparent RBE factors, or "compound factors" for the various dose components in BNCT. PMID:8175397

  11. Radiative neutron capture on a proton at big-bang nucleosynthesis energies

    SciTech Connect

    Ando, S. [Theory Group, TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada); Department of Physics and Institute of Basic Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Cyburt, R. H. [Theory Group, TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada); Hong, S. W. [Department of Physics and Institute of Basic Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Hyun, C. H. [Department of Physics and Institute of Basic Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); School of Physics, Seoul National University, Seoul 151-742 (Korea, Republic of)

    2006-08-15

    The total cross section for radiative neutron capture on a proton, np{yields}d{gamma}, is evaluated at big-bang nucleosynthesis (BBN) energies. The electromagnetic transition amplitudes are calculated up to next-to-leading-order within the framework of pionless effective field theory with dibaryon fields. We also calculate the d{gamma}{yields}np cross section and the photon analyzing power for the d{gamma}(vector sign){yields}np process from the amplitudes. The values of low-energy constants that appear in the amplitudes are estimated by a Markov Chain Monte Carlo analysis using the relevant low-energy experimental data. Our result agrees well with those of other theoretical calculations except for the np{yields}d{gamma} cross section at some energies estimated by an R-matrix analysis. We also study the uncertainties in our estimation of the np{yields}d{gamma} cross section at relevant BBN energies and find that the estimated cross section is reliable to within {approx}1% error.

  12. Boron neutron capture therapy outcomes for advanced or recurrent head and neck cancer

    PubMed Central

    Suzuki, Minoru; Kato, Ituro; Aihara, Teruhito; Hiratsuka, Junichi; Yoshimura, Kenichi; Niimi, Miyuki; Kimura, Yoshihiro; Ariyoshi, Yasunori; Haginomori, Shin-ichi; Sakurai, Yoshinori; Kinashi, Yuko; Masunaga, Shin-ichiro; Fukushima, Masanori; Ono, Koji; Maruhashi, Akira

    2014-01-01

    We retrospectively review outcomes of applying boron neutron capture therapy (BNCT) to unresectable advanced or recurrent head and neck cancers. Patients who were treated with BNCT for either local recurrent or newly diagnosed unresectable head or neck cancers between December 2001 and September 2007 were included. Clinicopathological characteristics and clinical outcomes were retrieved from hospital records. Either a combination of borocaptate sodium and boronophenylalanine (BPA) or BPA alone were used as boron compounds. In all the treatment cases, the dose constraint was set to deliver a dose <10–12 Gy-eq to the skin or oral mucosa. There was a patient cohort of 62, with a median follow-up of 18.7 months (range, 0.7–40.8). A total of 87 BNCT procedures were performed. The overall response rate was 58% within 6 months after BNCT. The median survival time was 10.1 months from the time of BNCT. The 1- and 2-year overall survival (OS) rates were 43.1% and 24.2%, respectively. The major acute Grade 3 or 4 toxicities were hyperamylasemia (38.6%), fatigue (6.5%), mucositis/stomatitis (9.7%) and pain (9.7%), all of which were manageable. Three patients died of treatment-related toxicity. Three patients experienced carotid artery hemorrhage, two of whom had coexistent infection of the carotid artery. This study confirmed the feasibility of our dose-estimation method and that controlled trials are warranted. PMID:23955053

  13. ARE THERE ANY STARS LACKING NEUTRON-CAPTURE ELEMENTS? EVIDENCE FROM STRONTIUM AND BARIUM

    SciTech Connect

    Roederer, Ian U., E-mail: iur@obs.carnegiescience.edu [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)

    2013-01-01

    The cosmic dispersion in the abundances of the heavy elements strontium and barium in halo stars is well known. Strontium and barium are detected in most cool, metal-poor giants, but are these elements always detectable? To identify stars that could be considered probable candidates for lacking these elements, I examine the stellar abundance data available in the literature for 1148 field stars and 226 stars in dwarf galaxies, 776 of which have metallicities lower than [Fe/H] <-2.0. Strontium or barium have been detected in all field, globular cluster, and dwarf galaxy environments studied. All upper limits are consistent with the lowest detected ratios of [Sr/H] and [Ba/H]. The frequent appearance of these elements raises the intriguing prospect that at least one kind of neutron-capture reaction operates as often as the nucleosynthesis mechanisms that produce lighter elements, such as magnesium, calcium, or iron, although the yields of heavy elements may be more variable.

  14. Boron neutron capture therapy outcomes for advanced or recurrent head and neck cancer.

    PubMed

    Suzuki, Minoru; Kato, Ituro; Aihara, Teruhito; Hiratsuka, Junichi; Yoshimura, Kenichi; Niimi, Miyuki; Kimura, Yoshihiro; Ariyoshi, Yasunori; Haginomori, Shin-Ichi; Sakurai, Yoshinori; Kinashi, Yuko; Masunaga, Shin-Ichiro; Fukushima, Masanori; Ono, Koji; Maruhashi, Akira

    2014-01-01

    We retrospectively review outcomes of applying boron neutron capture therapy (BNCT) to unresectable advanced or recurrent head and neck cancers. Patients who were treated with BNCT for either local recurrent or newly diagnosed unresectable head or neck cancers between December 2001 and September 2007 were included. Clinicopathological characteristics and clinical outcomes were retrieved from hospital records. Either a combination of borocaptate sodium and boronophenylalanine (BPA) or BPA alone were used as boron compounds. In all the treatment cases, the dose constraint was set to deliver a dose <10-12 Gy-eq to the skin or oral mucosa. There was a patient cohort of 62, with a median follow-up of 18.7 months (range, 0.7-40.8). A total of 87 BNCT procedures were performed. The overall response rate was 58% within 6 months after BNCT. The median survival time was 10.1 months from the time of BNCT. The 1- and 2-year overall survival (OS) rates were 43.1% and 24.2%, respectively. The major acute Grade 3 or 4 toxicities were hyperamylasemia (38.6%), fatigue (6.5%), mucositis/stomatitis (9.7%) and pain (9.7%), all of which were manageable. Three patients died of treatment-related toxicity. Three patients experienced carotid artery hemorrhage, two of whom had coexistent infection of the carotid artery. This study confirmed the feasibility of our dose-estimation method and that controlled trials are warranted. PMID:23955053

  15. Spectroscopic Study of 63Ni via Cold Neutron Capture Reaction: I. Nuclear Structure of 63Ni

    NASA Astrophysics Data System (ADS)

    Oshima, Masumi; Kin, Tadahiro; Nakamura, Shoji; Honma, Michio; Minato, Futoshi; Hayakawa, Takehito; Hara, Kaoru Y.; Kimura, Atsushi; Koizumi, Mitsuo; Harada, Hideo; Goto, Jun; Murakami, Yukihiro

    2012-08-01

    The ?-radiation has been investigated for 63Ni produced by cold neutron capture in an enriched 62Ni sample. The 315 ?-rays produced were placed in a 63Ni level scheme, in which 272 placements are new. We determined the excitation energies with 0.2--0.8 keV error and the branching ratios of 62 bound levels in 63Ni, including 30 new levels. The Q-value of the 62Ni(n,?)63Ni reaction amounts to 6837.75± 0.18 keV. A large-scale shell-model calculation was performed that included the four single-particle orbits of 0f7/2, 1p3/2, 0f5/2, and 1p1/2, assuming an inert 40Ca core for negative-parity states, and those of 1p3/2, 0f5/2, 1p1/2, and 0g9/2, assuming a 56Ni core for positive-parity states. The energies of the low-lying 63Ni states were successfully reproduced. A mean-field statistical-model calculation was also performed by using a self-consistent interaction between the Hartree--Fock + Bardeen--Cooper--Schrieffer method and the statistical calculation. The calculation result is consistent with the experimental level density of 63Ni.

  16. Evaluation of Lithium Gadolinium Borate Capture-Gated Spectrometer Neutron Efficiencies

    Microsoft Academic Search

    Nabil Menaa; Marcel Villani; Stephen Croft; Robert B. McElroy; Sasha A. Philips; J. Bart Czirr

    2009-01-01

    Accurate determination of neutron dose equivalent requires knowledge of the neutron energy distribution. Existing neutron spectrometers, such as Bonner sphere sets, are typically bulky and require long acquisition times. Hence, a handheld or portable system that could perform area monitoring with acceptable accuracy would be of interest. Such a device will require a detector that is efficient, and possesses gamma-neutron

  17. Monte Carlo-based treatment planning for boron neutron capture therapy using custom designed models automatically generated from CT data

    Microsoft Academic Search

    R. Zamenhof; E. Redmond; G. Solares; D. Katz; K. Riley; S. Kiger; O. Harling

    1996-01-01

    Purpose: A Monte Carlo-based treatment planning code for boron neutron capture therapy (BNCT), called NCTPLAN, has been developed in support of the NeW England Medical Center-Massachusetts Institute of Technology program in BNCT. This code has been used to plan BNCT irradiations in an ongoing peripheral melanoma BNCT protocol. The concept and design of the code is described and illustrative applications

  18. Unusual neutron-capture gamma-ray cascade in 124Te: A fingerprint of octupole-coupled multiphonon states

    Microsoft Academic Search

    R. Georgii; P. von Neumann-Cosel; T. von Egidy; M. Grinberg; V. A. Khitrov; J. Ott; P. Prokofjevs; A. Richter; W. Schauer; C. Schlegel; R. Schulz; L. J. Simonova; Ch. Stoyanov; A. M. Sukhovoj; A. V. Vojnov

    1995-01-01

    The properties of the special levels in 124Te that are strongly populated by thermal neutron-capture ?-rays have been determined with 123Te(n,?) and 124Te(?,??) experiments. The unusual decay pattern can be consistently explained within the quasiparticle-phonon model assuming a three-phonon |21+ ? 21+ ? 31?; 2?? configuration of the upper intermediate level at 3.101 MeV which exclusively decays to a close-lying

  19. Measurement of the neutron capture cross section of {sup 234}U in n-TOF at CERN

    SciTech Connect

    Dridi, W.; Aerts, G.; Andriamonje, S.; Berthoumieux, E.; Gunsing, F.; Pancin, J.; Perrot, L.; Plukis, A. [CEA/Saclay, DSM/DAPNIA, Gif-sur-Yvette (France); Abbondanno, U.; Fujii, K.; Milazzo, P. M.; Moreau, C. [Istituto Nazionale di Fisica Nucleare, Trieste (Italy); Alvarez, H.; Duran, I.; Paradela, C. [Universidade de Santiago de Compostela (Spain); Alvarez-Velarde, F.; Cano-Ott, D.; Embid-Segura, M.; Gonzalez-Romero, E.; Guerrero, C.; Villamarin, D.; Vincente, M. C. [Centro de Investigaciones Energeticas Medioambientales y Technologicas, Madrid (Spain); Andrzejewski, J.; Marganiec, J. [Univ. of Lodz, Lodz (Poland); Assimakopoulos, P.; Karadimos, D.; Karamanis, D.; Papachristodoulou, C.; Patronis, N. [Univ. of Ioannina (Greece); and others

    2006-07-01

    Accurate and reliable neutron capture cross sections are needed in many research areas, including stellar nucleosynthesis, advanced nuclear fuel cycles, waste transmutation, and other applied programs. In particular, the accurate knowledge of {sup 234}U(n, {gamma}) reaction cross section is required for the design and realization of nuclear power stations based on the thorium fuel cycle. We have measured the neutron capture cross section of {sup 234}U at the recently constructed neutron time-of-flight facility n-TOF at CERN [2] in the energy range from 0.03 eV to 1 MeV with high accuracy due to a combination of features unique in the world: A high instantaneous neutron fluence and excellent energy resolution of the n-TOF facility, an innovative Data Acquisition System based on flash ADCs [3] and the use of a high performance 4{Pi} BaF{sub 2} Total Absorption Calorimeter (TAC) as a detection device [4, 5], In this paper, we will describe the experimental apparatus including the various TAC components and its performance. We also will present results from the {sup 234}U(n, {gamma}) measurement. A sample of 38.7 mg of {sup 234}U{sub 3}O{sub 8} was pressed into a pellet and doubly encapsulated between Al and Ti foils which were 0.15 mm and 0.2 mm thick, respectively. Monte-Carlo simulations with GEANT4 [6] of the detector response have been performed. After the background subtraction and correction with dead time and pile-up, the capture yield from 0.03 eV up to 1.5 keV was derived. Preliminary analysis of the capture yield in terms of R-matrix resonance parameters is discussed. (authors)

  20. The combined effect of boronophenylalanine and borocaptate in boron neutron capture therapy for SCCVII tumors in mice

    Microsoft Academic Search

    Koji Ono; Shin-ichiro Masunaga; Minoru Suzuki; Yuko Kinashi; Masao Takagaki; Mitsuhiko Akaboshi

    1999-01-01

    Purpose: To increase the effect of boron neutron capture therapy (BNCT) on tumors in vivo, the combined effects of para-boronophenylalanine (BPA) and borocaptate sodium (BSH) were investigated.Methods and Materials: 10B-enriched BPA and BSH were administered to C3H\\/He mice bearing SCCVII tumors by intragastric and intravenous injections, respectively. The colony formation and tumor control assays were employed for investigating antitumor effects

  1. Clinical trials of boron neutron capture therapy [in humans] [at Beth Israel Deaconess Medical Center][at Brookhaven National Laboratory

    SciTech Connect

    Wallace, Christine

    2001-05-29

    Assessment of research records of Boron Neutron Capture Therapy was conducted at Brookhaven National Laboratory and Beth Israel Deaconess Medical Center using the Code of Federal Regulations, FDA Regulations and Good Clinical Practice Guidelines. Clinical data were collected from subjects' research charts, and differences in conduct of studies at both centers were examined. Records maintained at Brookhaven National Laboratory were not in compliance with regulatory standards. Beth Israel's records followed federal regulations. Deficiencies discovered at both sites are discussed in the reports.

  2. Comparison between the activation cross sections and integrated cross sections for the radiative capture of 14 MeV neutrons

    Microsoft Academic Search

    F. Cvelbar; A. Hudoklin; M. Potokar

    1970-01-01

    Cross sections obtained by the integration of prompt gamma-ray spectra from the radiative capture of 14 MeV neutrons in a series of elements are presented and compared wilh the activation cross sections reported by different authors. In contrast to the activation cross-section values, which are scattered between 1 mb and 10 mb as a function of mass number, the integrated

  3. Boron neutron capture therapy (BNCT) for the treatment of spontaneous nasal planum squamous cell carcinoma in felines

    Microsoft Academic Search

    Verónica A. Trivillin; Elisa M. Heber; Monica Rao; María A. Cantarelli; Maria E. Itoiz; David W. Nigg; Osvaldo Calzetta; Herman Blaumann; Juan Longhino; Amanda E. Schwint

    2008-01-01

    Recently, Boron neutron capture therapy (BNCT) was successfully applied to treat experimental squamous cell carcinomas (SCC)\\u000a of the hamster cheek pouch mucosa, with no damage to normal tissue. It was also shown that treating spontaneous nasal planum\\u000a SCC in terminal feline patients with low dose BNCT is safe and feasible. In an extension of this work, the present study aimed

  4. Convection enhanced delivery of boronated EGF as a molecular targeting agent for neutron capture therapy of brain tumors

    Microsoft Academic Search

    Weilian Yang; Rolf F. Barth; Gong Wu; Tianyao Huo; Werner Tjarks; Michael Ciesielski; Robert A. Fenstermaker; Brain D. Ross; Carol J. Wikstrand; Kent J. Riley; Peter J. Binns

    2009-01-01

    In the present study, we have evaluated a boronated dendrimer-epidermal growth factor (BD-EGF) bioconjugate as a molecular\\u000a targeting agent for boron neutron capture therapy (BNCT) of the human EGFR gene-transfected F98 rat glioma, designated F98EGFR. EGF was chemically linked to a heavily boronated polyamidoamine dendrimer (BD) by means of the heterobifunctional reagent,\\u000a mMBS. Biodistribution studies were carried out at 6 h

  5. Enantioselective synthesis of L-(-)-4-boronophenylalanine (L-BPA). [For boron neutron capture therapy of metastatic melanomas

    Microsoft Academic Search

    Samsel

    1991-01-01

    4-Boronophenylalanine (BPA) is being investigated for boron neutron capture therapy of metastatic melanomas and other tumors. It is believed that the pure enantiomer L-BPA is more biologically active than the D,L racemate. This patent discloses a method of making substantially pure L-BPA. The method comprises the steps of reacting 4-bromobenzaldehyde with ethylene glycol, reacting the resulting acetal with Mg to

  6. Neutron Capture Cross Section Measurement of 151Sm at the CERN Neutron Time of Flight Facility (n_TOF)

    SciTech Connect

    Abbondanno, U. [Instituto Nazionale de Fisica Nucleare, Trieste, Italy; Koehler, Paul Edward [ORNL; Collaboration, n_TOF [Collaboration affiliations

    2004-10-01

    The151Sm(n,?)152Sm cross section has been measured at the spallation neutron facility n{_}TOF at CERN in the energy range from 1 eV to 1 MeV. The new facility combines excellent resolution in neutron time-of-flight, low repetition rates, and an unsurpassed instantaneous luminosity, resulting in rather favorable signal/background ratios. The 151Sm cross section is of importance for characterizing neutron capture nucleosynthesis in asymptotic giant branch stars. At a thermal energy of ??kT=30??keV the Maxwellian averaged cross section of this unstable isotope (t1/2=93??yr) was determined to be 3100{+-}160??mb, significantly larger than theoretical predictions.

  7. Significant change in the construction of a door to a room with slowed down neutron field by means of commonly used inexpensive protective materials.

    PubMed

    Konefa?, Adam; ?aciak, Marcin; Dawidowska, Anna; Osewski, Wojciech

    2014-12-01

    The detailed analysis of nuclear reactions occurring in materials of the door is presented for the typical construction of an entrance door to a room with a slowed down neutron field. The changes in the construction of the door were determined to reduce effectively the level of neutron and gamma radiation in the vicinity of the door in a room adjoining the neutron field room. Optimisation of the door construction was performed with the use of Monte Carlo calculations (GEANT4). The construction proposed in this paper bases on the commonly used inexpensive protective materials such as borax (13.4 cm), lead (4 cm) and stainless steel (0.1 and 0.5 cm on the side of the neutron field room and of the adjoining room, respectively). The improved construction of the door, worked out in the presented studies, can be an effective protection against neutrons with energies up to 1 MeV. PMID:24324249

  8. Charged-partricle and neutron-capture processes in the high-entropy wind of core-collapse supernovae.

    SciTech Connect

    Farouqi, K.; Kratz, K.-L.; Pfeiffer, B.; Rauscher, T.; Thielemann, F.-K.; Truran, J. W.; Physics; Univ. of Chicago; Joint Inst. for Nuclear Astrophysics; Univ. Mainz; Virtual Inst. for Nuclear Structure and Astrophysics; Max-Planck-Inst. fur Chemie; Univ. of Basel

    2010-04-01

    The astrophysical site of the r-process is still uncertain, and a full exploration of the systematics of this process in terms of its dependence on nuclear properties from stability to the neutron drip-line within realistic stellar environments has still to be undertaken. Sufficiently high neutron-to-seed ratios can only be obtained either in very neutron-rich low-entropy environments or moderately neutron-rich high-entropy environments, related to neutron star mergers (or jets of neutron star matter) and the high-entropy wind of core-collapse supernova explosions. As chemical evolution models seem to disfavor neutron star mergers, we focus here on high-entropy environments characterized by entropy S, electron abundance Y{sub e}, and expansion velocity V{sub exp}. We investigate the termination point of charged-particle reactions, and we define a maximum entropy S{sub final} for a given V{sub exp} and Y{sub e}, beyond which the seed production of heavy elements fails due to the very small matter density. We then investigate whether an r-process subsequent to the charged-particle freeze-out can in principle be understood on the basis of the classical approach, which assumes a chemical equilibrium between neutron captures and photodisintegrations, possibly followed by a {beta}-flow equilibrium. In particular, we illustrate how long such a chemical equilibrium approximation holds, how the freeze-out from such conditions affects the abundance pattern, and which role the late capture of neutrons originating from {beta}-delayed neutron emission can play. Furthermore, we analyze the impact of nuclear properties from different theoretical mass models on the final abundances after these late freeze-out phases and {beta}-decays back to stability. As only a superposition of astrophysical conditions can provide a good fit to the solar r-abundances, the question remains how such superpositions are attained, resulting in the apparently robust r-process pattern observed in low metallicity stars.

  9. CHARGED-PARTICLE AND NEUTRON-CAPTURE PROCESSES IN THE HIGH-ENTROPY WIND OF CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Farouqi, K.; Truran, J. W. [Department of Astrophysics and Astronomy, University of Chicago, Chicago, IL 60637 (United States); Kratz, K.-L. [HGF Virtuelles Institut fuer Kernstruktur und Nukleare Astrophysik, Universitaet Mainz, D-55128 Mainz (Germany); Pfeiffer, B. [Institut fuer Kernchemie, Universitaet Mainz, D-55128 Mainz (Germany); Rauscher, T.; Thielemann, F.-K., E-mail: farouqi@uchicago.ed, E-mail: truran@nova.uchicago.ed, E-mail: BPfeiffe@uni-mainz.d, E-mail: k-l.Kratz@mpic.d, E-mail: Thomas.Rauscher@unibas.c, E-mail: F-K.Thielemann@unibas.c [Department of Physics, University of Basel, 4056 Basel (Switzerland)

    2010-04-01

    The astrophysical site of the r-process is still uncertain, and a full exploration of the systematics of this process in terms of its dependence on nuclear properties from stability to the neutron drip-line within realistic stellar environments has still to be undertaken. Sufficiently high neutron-to-seed ratios can only be obtained either in very neutron-rich low-entropy environments or moderately neutron-rich high-entropy environments, related to neutron star mergers (or jets of neutron star matter) and the high-entropy wind of core-collapse supernova explosions. As chemical evolution models seem to disfavor neutron star mergers, we focus here on high-entropy environments characterized by entropy S, electron abundance Y{sub e} , and expansion velocity V{sub exp}. We investigate the termination point of charged-particle reactions, and we define a maximum entropy S{sub final} for a given V{sub exp} and Y{sub e} , beyond which the seed production of heavy elements fails due to the very small matter density. We then investigate whether an r-process subsequent to the charged-particle freeze-out can in principle be understood on the basis of the classical approach, which assumes a chemical equilibrium between neutron captures and photodisintegrations, possibly followed by a beta-flow equilibrium. In particular, we illustrate how long such a chemical equilibrium approximation holds, how the freeze-out from such conditions affects the abundance pattern, and which role the late capture of neutrons originating from beta-delayed neutron emission can play. Furthermore, we analyze the impact of nuclear properties from different theoretical mass models on the final abundances after these late freeze-out phases and beta-decays back to stability. As only a superposition of astrophysical conditions can provide a good fit to the solar r-abundances, the question remains how such superpositions are attained, resulting in the apparently robust r-process pattern observed in low metallicity stars.

  10. Radiative Neutron Capture on 9Be, 14C, 14N, 15N and 16O at Thermal and Astrophysical Energies

    NASA Astrophysics Data System (ADS)

    Dubovichenko, Sergey; Dzhazairov-Kakhramanov, Albert; Afanasyeva, Nadezhda

    2013-10-01

    The total cross-sections of the radiative neutron capture processes on 9Be, 14C, 14N, 15N and 16O are described in the framework of the modified potential cluster model with the classification of orbital states according to Young tableaux. The continued interest in the study of these reactions is due, on the one hand, to the important role played by this process in the analysis of many fundamental properties of nuclei and nuclear reactions, and, on the other hand, to the wide use of the capture cross-section data in the various applications of nuclear physics and nuclear astrophysics, and, also, to the importance of the analysis of primordial nucleosynthesis in the Universe. This article is devoted to the description of results for the processes of the radiative neutron capture on certain light atomic nuclei at thermal and astrophysical energies. The considered capture reactions are not part of stellar thermonuclear cycles, but involve in the reaction chains of inhomogeneous Big Bang models.

  11. A nude rat model for neutron capture therapy of human intracerebral melanoma

    SciTech Connect

    Barth, R.F.; Matalka, K.Z.; Bailey, M.Q.; Staubus, A.E.; Soloway, A.H.; Moeschberger, M.L. (Ohio State Univ., Columbus, OH (United States)); Coderre, J.A. (Brookhaven National Lab., Upton, NY (United States)); Rofstad, E.K. (Norwegian Radium Hospital, Oslo (Norway))

    1994-03-30

    The present study was carried out to determine the efficacy of Boron Neutron Capture Therapy (BNCT) for intracerebral melanoma using nude rats, the human melanoma cell line MRA 27, and boronophenylalanine as the capture agent. MRA 27 cells (2 [times] 10[sup 5]) were implanted intracerebrally, and 30 days later, 120 mg of [sup 10]B-L-BPA were injected intraperitoneally into nude rats. Thirty days following implantation, tumor bearing rats were irradiated at the Brookhaven Medical Research Reactor. Six hours following administration of BPA, tumor, blood, and normal brain boron-10 levels were 23.7, 9.4, and 8.4 [mu]g/g respectively. Median survival time of untreated rats was 44 days compared to 76 days and 93 days for those receiving physical doses of 2.73 Gy and 3.64 Gy, respectively. Rats that have received both [sup 10]B-BPA and physical doses of 1.82, 2.73, or 3.64 Gy had median survival times of 170, 182, and 262 days, respectively. Forty percent of rats that had received the highest tumor dose (10.1 Gy) survived for > 300 days and in a replicate experiment 21% of the rats were longterm survivors (>220 days). Animals that received 12 Gy in a single dose or 18 Gy fractionated (2 Gy [times] 9) of gamma photons from a [sup 137]Cs source had median survival times of 86 and 79 days, respectively, compared to 47 days for untreated animals. Histopathologic examination of the brains of longterm surviving rats, euthanized at 8 or 16 months following BNCT, showed no residual tumor, but dense accumulations of melanin laden macrophages and minimal gliosis were observed. Significant prolongations in median survival time were noted in nude rats with intracerebral human melanoma that had received BNCT, thereby suggesting therapeutic efficacy. Large animal studies should be carried out to further assess BNCT of intracerebral melanoma before any human trials are contemplated. 49 refs., 7 figs., 2 tabs.

  12. Preliminary evaluation of neutron capture cross sections for /sup 144/Sm, /sup 145/Sm and /sup 145/Pm

    SciTech Connect

    Gardner, D.G.; Gardner, M.A.

    1986-02-13

    We have made preliminary neutron-capture cross-section calculations of the Hauser-Feshbach type for the isotopes /sup 144/Sm, /sup 145/Sm, and /sup 145/Pm to investigate the production of radioactive /sup 145/Pm by neutron capture on the stable isotope /sup 144/Sm. The calculations were made for incident neutron energies from 2.5 MeV to about 1/sup -4/ or 10/sup -5/ MeV, wherever the first unbound resonance was estimated to occur in each case. At that energy, the calculated value was reduced by a somewhat arbitrary factor, and the excitation function extended down to thermal energy using a (E/sub n/)/sup -1/2/ energy dependence. Since very large uncertainties are associated with the position and magnitude of the first unbound resonance and the subsequent extrapolation back to thermal energy, the cross sections in this low-energy region should not be considered more accurate than +- a factor of 10. For incident neutron energies above each step, the calculations represent an average through the separated and overlapping resonance regions and may be accurate to better than +- a factor of 2. 18 refs., 7 figs., 5 tabs.

  13. Boron neutron capture irradiation of the rat spinal cord: Histopathological evidence of a vascular-mediated pathogenesis

    SciTech Connect

    Morris, G. M.; Bywaters, A.; Hopewell, J.W. [Univ. of Oxford, Oxford (United Kingdom); Coderre, J.A. [Brookhaven National Lab., Upton, NY (United States)

    1996-09-01

    A histopathological study was carried out on the spinal cord of rats after boron neutron capture (BNC) irradiation. Rats were irradiated with thermal neutrons alone or in combination with borocaptate sodium (BSH) or p-boronophenylalanine (BPA). Spinal cords were examined 1 year after irradiation, or at earlier times in rats developing myelothapy. Considered overall, the pathology of the spinal cord after BNC irradiation was comparable with that reported previously after X irradiation of the spinal cord in the identical strain of rat. When BSH was used as the neutron capture agent, the biologically effective dose of radiation delivered to the CNS parechyma was a factor of {approx}2.7 lower than that delivered to the vascular endothelium. In effect, the blood vessels were selectively irradiated using this BNC modality. The resultant pathology was similar to that observed after irradiation with thermal neutrons alone or in the presence of BPA, situations in which the CNS vasculature was not selectively irradiated. This points to the vascular endothelium as being the critical target cell population, damage to which results in the development of the lesions seen in the spinal cord after BNC irradiation and, by inference, after irradiation with more conventional modalities. 37 refs., 6 figs., 4 tabs.

  14. Experimental and Simulated Characterization of a Beam Shaping Assembly for Accelerator- Based Boron Neutron Capture Therapy (AB-BNCT)

    NASA Astrophysics Data System (ADS)

    Burlon, Alejandro A.; Girola, Santiago; Valda, Alejandro A.; Minsky, Daniel M.; Kreiner, Andrés J.

    2010-08-01

    In the frame of the construction of a Tandem Electrostatic Quadrupole Accelerator facility devoted to the Accelerator-Based Boron Neutron Capture Therapy, a Beam Shaping Assembly has been characterized by means of Monte-Carlo simulations and measurements. The neutrons were generated via the 7Li(p, n)7Be reaction by irradiating a thick LiF target with a 2.3 MeV proton beam delivered by the TANDAR accelerator at CNEA. The emerging neutron flux was measured by means of activation foils while the beam quality and directionality was evaluated by means of Monte Carlo simulations. The parameters show compliance with those suggested by IAEA. Finally, an improvement adding a beam collimator has been evaluated.

  15. A Small-Animal Irradiation Facility for Neutron Capture Therapy Research at the RA-3 Research Reactor

    SciTech Connect

    Emiliano Pozzi; David W. Nigg; Marcelo Miller; Silvia I. Thorp; Amanda E. Schwint; Elisa M. Heber; Veronica A. Trivillin; Leandro Zarza; Guillermo Estryk

    2007-11-01

    The National Atomic Energy Commission of Argentina (CNEA) has constructed a thermal neutron source for use in Boron Neutron Capture Therapy (BNCT) applications at the RA-3 research reactor facility located in Buenos Aires. The Idaho National Laboratory (INL) and CNEA have jointly conducted some initial neutronic characterization measurements for one particular configuration of this source. The RA-3 reactor (Figure 1) is an open pool type reactor, with 20% enriched uranium plate-type fuel and light water coolant. A graphite thermal column is situated on one side of the reactor as shown. A tunnel penetrating the graphite structure enables the insertion of samples while the reactor is in normal operation. Samples up to 14 cm height and 15 cm width are accommodated.

  16. Boron neutron capture therapy (BNCT) for glioblastoma multiforme: A phase II study evaluating a prolonged high-dose of boronophenylalanine (BPA)

    Microsoft Academic Search

    Roger Henriksson; Jacek Capala; Annika Michanek; Sten-Åke Lindahl; Leif G. Salford; Lars Franzén; Erik Blomquist; Jan-Erik Westlin; A. Tommy Bergenheim

    2008-01-01

    Background and purposeTo evaluate the efficacy and safety of boron neutron capture therapy (BNCT) for glioblastoma multiforme (GBM) using a novel protocol for the boronophenylalanine–fructose (BPA-F) infusion.

  17. CONVECTION ENHANCED DELIVERY OF CARBORANYLPORPHYRINS FOR NEUTRON CAPTURE THERAPY OF BRAIN TUMORS

    PubMed Central

    Kawabata, Shinji; Yang, Weilian; Wu, Gong; Huo, Tianyao; Binns, Peter J.; Riley, Kent J.; Ongayi, Owendi; Gottumukkala, Vijay; Vicente, M. Graça H.

    2010-01-01

    Boron neutron capture therapy (BNCT) is based on the nuclear capture and fission reactions that occur when non-radioactive 10B is irradiated with low energy thermal neutrons to produce ?-particles (10B[n,?]7Li). Carboranylporphyrins are a class of substituted porphyrins containing multiple carborane clusters. Three of these have been evaluated in the present study: 5,10,15,20-tetra-(4-nido-carboranyphenyl)tetrabenzoporphyrin (H2TBP), 5,10,15,20-tetra-(4-nido-carboranylphenyl)porphyrin (H2TCP) and 5,15-di-[3,5-(nido-carboranylmethyl)phenyl]-porphyrin (H2DCP). The goals of this study were two-fold. First, to determine the biodistribution of H2TBP, H2TCP and H2DCP following intracerebral (i.c.) administration by means of short term (30 min) convection enhanced delivery (CED) or sustained delivery over 24 h by osmotic pumps to F98 glioma bearing rats. Second, to determine the efficacy of H2TCP and H2TBP as boron delivery agents for BNCT in F98 glioma bearing rats. Tumor boron concentrations immediately after i.c. osmotic pump delivery were high (36–88 µg/g) and they remained so at 24 h (62–103 µg/g) The corresponding normal brain concentrations were low (0.8–5.2 µg/g) and the blood and liver concentrations were all undetectable. Based on these data, therapy studies were initiated at the Massachusetts Institute of Technology (MIT) Research Reactor (MITRR) with H2TCP and H2TBP 24 h after CED or osmotic pump delivery. Mean survival times (MST) of untreated and irradiated control rats were 23±3 and 27±3 d, respectively, while animals that received H2TCP or H2TBP, followed by BNCT, had a MST of 35±4 d and 44±10 d, respectively, which were better than those obtained following i.v. administration of boronophenylalanine (37±3 d). However, since the tumor boron concentrations of the carboranylporphyrins were 3–5X > i.v. BPA (~25 µg/g), we had expected that the MSTs would have been greater. Histopathologic examination of brains of BNCT treated rats revealed that there were large numbers of porphyrin-laden macrophages, as well as extracellular accumulations of porphyrins indicating that the seemingly high tumor boron concentrations did not represent the true tumor cellular uptake. Our data are the first to show that carboranyl porphyrins are effective delivery agents for BNCT of an experimental brain tumor. Based on these results, we now are in the process of evaluating carboranylporphyrins that could have enhanced cellular uptake following administration and improved therapeutic efficacy. PMID:20848301

  18. Lithium-6 filter for a fission converter-based Boron Neutron Capture Therapy irradiation facility beam

    E-print Network

    Gao, Wei, Ph. D.

    2005-01-01

    (cont.) A storage system was designed to contain the lithium-6 filter safely when it is not in use. A mixed field dosimetry method was used to measure the photon, thermal neutron and fast neutron dose. The measured advantage ...

  19. Parity violation in neutron capture on the proton: Determining the weak pion-nucleon coupling

    NASA Astrophysics Data System (ADS)

    de Vries, J.; Li, N.; Meißner, Ulf-G.; Nogga, A.; Epelbaum, E.; Kaiser, N.

    2015-07-01

    We investigate the parity-violating analyzing power in neutron capture on the proton at thermal energies in the framework of chiral effective field theory. By combining this analysis with a previous analysis of parity violation in proton-proton scattering, we are able to extract the size of the weak pion-nucleon coupling constant. The uncertainty is significant and dominated by the experimental error which is expected to be reduced soon. the one-body convection current in combination with the PV OPE potential, the two-body PC OPE currents in combination with the PV OPE potential, the two-body PV OPE currents. All these contributions appear at the same order in the chiral counting and we present the results in Table 2. The individual contributions are all of the same order, as expected from the power counting, and suffer only from minor uncertainties due to cut-off variations. However, the total result has a much larger relative uncertainty due to cancellations between the individual contributions. These cancellations were found also in Ref. [40] where the AV18 potential has been applied in combination with the same currents. Our central value is also in good agreement with results based on various phenomenological strong potentials and the Siegert theorem for the electric dipole currents [39,41,42]. These calculations do, however, not provide an uncertainty estimate. In Ref. [43] a smaller uncertainty was found when varying the cut-off (roughly ± 0.015h?), but the authors did not vary the strong potential simultaneously. In addition the Siegert theorem was applied for the electric dipole currents. The significant dependence of the total result on the cut-off parameters indicates that the extraction of h? from data on a? is less clean than might be expected. Having available the prediction for a? as a function of h?, we can now compare to data. For a long time only a bound on a? existed

  20. Power burst facility/boron neutron capture therapy program for cancer treatment. [Borocaptate sodium

    SciTech Connect

    Dorn, R.V. III.

    1990-11-01

    Highlights of the Power Burst Facility/Boron Neutron Capture Therapy (PBF/BNCT) Program in November, 1990 are described. One of our major projects is support of technological development. In this area, progress has been seen in gross boron analysis of biological samples, higher purity borocaptate sodium (BSH), planning of experiments to investigate BSH biochemistry and oxidation products, bidding out for an ion microscope to investigate subcellular distribution of boron, and reduction of the gamma field in the irradiation room due to addition of lithiated polyethylene shielding. No progress was made on noninvasive boron quantitation, because the MRI system used is being upgraded, and the boron MR software must be rewritten. Brandy'' Hoff, a canine patient in the Large Animal Model studies, passed her one year physical and neurological exam. Three of the last four dogs treated for spontaneous brain tumors are doing well. Researchers at the University of Utah are planning human pharmacokinetic studies of BSH. BSH and BSS uptake in exemptions of terminal glioblastoma patients will be investigated. Layout and planning of tasks to begin PBF/BNCT Program reactor modifications have been initiated. The final design review for the bismuth reflector core partition sheet and lower orifice plate was completed on November 20, 1990. Agreements with DOE-ID relating to expenditure of the $13M for the PBF/BNCT Program have been reached. A review of the program by the National Academy of Science was requested by Admiral Watkins and took place in Washington, DC on November 5, 1990. This progress report also contains a summary of the 1990 accomplishments within the melanoma project. 2 figs. (MHB)

  1. Boron neutron capture therapy for newly diagnosed glioblastoma multiforme: an assessment of clinical potential

    PubMed Central

    Sköld, K; Gorlia, T; Pellettieri, L; Giusti, V; H-Stenstam, B; Hopewell, J W

    2010-01-01

    The purpose of this study was to assess the potential of boron neutron capture therapy (BNCT), with a 6-h infusion of the boron carrier l-boronophenylalanine as a fructose preparation (BPA-f), as first-line radiotherapy for newly diagnosed glioblastoma multiforme (GBM). Patient survival data from a Phase II study using BNCT were compared with retrospective data from the two arms of a Phase III study using conventional radiotherapy (RT) in the reference arm and using RT plus concomitant and adjuvant medication with temozolomide (TMZ) in the experimental arm, and were also compared with small subgroups of these patients for whom the methylation status of the MGMT (O6-methylguanine–DNA methyltransferase) DNA repair gene was known. Differences in the baseline characteristics, salvage therapy after recurrence and levels of severe adverse events were also considered. The results indicate that BNCT offers a treatment that is at least as effective as conventional RT alone. For patients with an unmethylated MGMT DNA repair gene, a possible clinical advantage of BNCT over RT/TMZ was suggested. BNCT is a single-day treatment, which is of convenience to patients, with mild side effects, which would offer an initial 6 weeks of good-quality life during the time when patients would otherwise be undergoing daily treatments with RT and TMZ. It is suggested that the use of BNCT with a 6-h infusion of BPA-f should be explored in a stratified randomised Phase II trial in which patients with the unmethylated MGMT DNA repair gene are offered BNCT in the experimental arm and RT plus TMZ in the reference arm. PMID:20603410

  2. Derivations of relative biological effectiveness for the high-let radiations produced during boron neutron capture irradiations of the 9L rat gliosarcoma in vitro and in vivo

    Microsoft Academic Search

    Jeffrey A. Coderre; Michael S. Makar; Peggy L. Micca; Marta M. Nawrocky; Hungyuan B. Liu; Darrel D. Joel; Daniel N. Slatkin; Howard I. Amols

    1993-01-01

    The purpose of this study was to independently determine RBE values for all of the boron neutron capture therapy dose components. Clonogenic cell survival data were obtained for 9L rat gliosarcoma cells irradiated in the Brookhaven Medical Research Reactor thermal neutron beam both in vitro and as an intracerebral tumor. These data were analyzed using the linear quadratic model for

  3. Indirect Determination of Neutron Capture Cross Sections on Spherical and Near-Spherical Nuclei Using the Surrogate Method

    SciTech Connect

    Goldblum, B. L. [Univ. California-Berkeley/UTK/LBNL; Wiedeking, M. [LLNL/iThemba LABS, SA; Reed, T. [UTK; Alfonso, K. [University of California-Berkeley; Allmond, James M [ORNL; Bernstein, L. A. [Lawrence Livermore National Laboratory (LLNL); Bleuel, D.L. [Lawrence Livermore National Laboratory (LLNL); Dietrich, F. S. [Lawrence Livermore National Laboratory (LLNL); Hatarik, R. [Lawrence Berkeley National Laboratory (LBNL); Lake, P. T. [Lawrence Berkeley National Laboratory (LBNL); Lee, I.-Y. [Lawrence Berkeley National Laboratory (LBNL); Lesher, S. R. [Lawrence Livermore National Laboratory (LLNL); Paschalis, S. [Lawrence Berkeley National Laboratory (LBNL); Petri, M. [Lawrence Berkeley National Laboratory (LBNL); Phair, L. [Lawrence Berkeley National Laboratory (LBNL); Scielzo, N.D. [Lawrence Livermore National Laboratory (LLNL); Vial, R. [Univ. California-Berkeley/Grenoble INP-Phelma, France; Baktash, Cyrus [ORNL; Vujic, J. [University of California-Berkeley

    2012-01-01

    The 92Mo(n, ) cross section was obtained using both the absolute surrogate approach and surrogate ratio method (SRM), relative to the 94 Mo(n, ) cross section, in an equivalent neutron energy range of 80 to 890 keV. Excited 93Mo and 95Mo nuclei were populated using the 92Mo(d, p) and 94Mo(d, p) reactions, respectively. Both discrete and statistical tagging approaches were employed to identify the -decay channel and were examined in terms of their sensitivity to the initial angular momentum population distribution. The absolute surrogate 92 Mo(n, ) cross sections disagree with evaluated neutron capture cross section data by as much as a factor of 4, whereas the results obtained using the SRM trend more favorably with the evaluated result. Experimental results suggest that discrete and statistical tagging approaches may sample different contributions of the cascade for near-spherical nuclei. This work uses the surrogate method in the determination of neutron capture cross sections on spherical and quasispherical nuclei in the mass-90 region and provides a possible pathway to extend the SRM to a broader mass range.

  4. Indirect determination of neutron capture cross sections on spherical and near-spherical nuclei using the surrogate method

    NASA Astrophysics Data System (ADS)

    Goldblum, B. L.; Wiedeking, M.; Reed, T.; Alfonso, K.; Allmond, J. M.; Bernstein, L. A.; Bleuel, D. L.; Dietrich, F. S.; Hatarik, R.; Lake, P. T.; Lee, I.-Y.; Lesher, S. R.; Paschalis, S.; Petri, M.; Phair, L.; Scielzo, N. D.; Vial, R.; Vujic, J.

    2012-05-01

    The 92Mo(n,?) cross section was obtained using both the absolute surrogate approach and surrogate ratio method (SRM), relative to the 94Mo(n,?) cross section, in an equivalent neutron energy range of 80 to 890 keV. Excited 93Mo and 95Mo nuclei were populated using the 92Mo(d,p) and 94Mo(d,p) reactions, respectively. Both discrete and statistical tagging approaches were employed to identify the ?-decay channel and were examined in terms of their sensitivity to the initial angular momentum population distribution. The absolute surrogate 92Mo(n,?) cross sections disagree with evaluated neutron capture cross section data by as much as a factor of 4, whereas the results obtained using the SRM trend more favorably with the evaluated result. Experimental results suggest that discrete and statistical tagging approaches may sample different contributions of the ? cascade for near-spherical nuclei. This work uses the surrogate method in the determination of neutron capture cross sections on spherical and quasispherical nuclei in the mass-90 region and provides a possible pathway to extend the SRM to a broader mass range.

  5. Unblocking of the Gamow-Teller strength in stellar electron capture on neutron-rich Germanium isotopes

    E-print Network

    K. Langanke; E. Kolbe; D. J. Dean

    2000-12-11

    We propose a new model to calculate stellar electron capture rates for neutron-rich nuclei. These nuclei are encountered in the core-collapse of a massive star. Using the Shell Model Monte Carlo approach, we first calculate the finite temperature occupation numbers in the parent nucleus. We then use these occupation numbers as a starting point for calculations using the random phase approximation. Using the RPA approach, we calculate electron capture rates including both allowed and forbidden transitions. Such a hybrid model is particularly useful for nuclei with proton numbers Z40, where allowed Gamow-Teller transitions are only possible due to configuration mixing by the residual interaction and by thermal unblocking of $pf$-shell single-particle states. Using the even germanium isotopes Ge-68 to Ge-76 as examples, we demonstrate that the configuration mixing is strong enough to unblock the Gamow-Teller transitions at all temperatures relevant to core-collapse supernovae.

  6. Upper Bounds on Parity Violating Gamma-Ray Asymmetries in Compound Nuclei from Polarized Cold Neutron Capture

    E-print Network

    M. T. Gericke; J. D. Bowman; R. D. Carlini; T. E. Chupp; K. P. Coulter; M. Dabaghyan; M. Dawkins; D. Desai; S. J. Freedman; T. R. Gentile; R. C. Gillis; G. L. Greene; F. W. Hersman; T. Ino; G. L. Jones; M. Kandes; B. Lauss; M. Leuschner; W. R. Lozowski; R. Mahurin; M. Mason; Y. Masuda; G. S. Mitchell; S. Muto; H. Nann; S. A. Page; S. I. Penttila; W. D. Ramsay; S. Santra; P. -N. Seo; E. I. Sharapov; T. B. Smith; W. M. Snow; W. S. Wilburn; V. Yuan; H. Zhu

    2006-08-03

    Parity-odd asymmetries in the electromagnetic decays of compound nuclei can sometimes be amplified above values expected from simple dimensional estimates by the complexity of compound nuclear states. In this work we use a statistical approach to estimate the root mean square (RMS) of the distribution of expected parity-odd correlations $\\vec{s_{n}} \\cdot \\vec{k_{\\gamma}}$, where $\\vec {s_{n}}$ is the neutron spin and $\\vec{k_{\\gamma}}$ is the momentum of the gamma, in the integrated gamma spectrum from the capture of cold polarized neutrons on Al, Cu, and In and we present measurements of the asymmetries in these and other nuclei. Based on our calculations, large enhancements of asymmetries were not predicted for the studied nuclei and the statistical estimates are consistent with our measured upper bounds on the asymmetries.

  7. Performance measurement of the scintillator with optical fiber detector for boron neutron capture therapy.

    PubMed

    Komeda, M; Kumada, H; Ishikawa, M; Nakamura, T; Yamamoto, K; Matsumura, A

    2009-07-01

    The thermal neutron flux can be easily measured in real time by using the scintillator with optical fiber (SOF) detector. However the irradiation damage under high-intensity neutron flux causes deterioration of the SOF detector due to radiation damage to the plastic scintillator in which (6)LiF is blended. After irradiating the SOF detector for 4 h (thermal neutron fluence is approximately 2.0 x 10(13)neutrons/cm(2)), the sensitivity of the SOF detector decreased by 3.0%. After irradiating the SOF detector for 2 months (thermal neutron fluence approximately 6.4 x 10(14)neutrons/cm(2)), the sensitivity was reduced to 42% of baseline. Supposing that the thermal neutron fluence is 2 x 10(12)neutrons/cm(2) on the surface of a patient in a BNCT treatment, the sensitivity of the SOF detector is reduced by approximately 0.3%. This report presents investigations on the deterioration of the SOF detector in irradiation experiments. PMID:19398347

  8. Use of nude mice in experimental neutron capture therapy with 10B-BPA

    SciTech Connect

    Tamaoki, N.; Ueda, M.; Tamauchi, S.; Yamamoto, K.; Mishima, Y. (Tokai Univ., Kanagawa-ken (Japan))

    1989-07-01

    Mouse B16 melanoma allografts in nude mice were successfully treated by thermal neutron irradiation after IP injection of 10B-paraboronophenylalanine hydrochloride. The tumor growth was significantly suppressed for 4 weeks after irradiation, compared with animals given neutron irradiation alone. Tumor-bearing nude mice were shown to be useful for evaluating the treatment for melanoma.

  9. Neutronics design of the INEL (Idaho National Engineering Laboratory) facility for boron neutron capture therapy clinical trials

    Microsoft Academic Search

    D. K. Parsons; F. J. Wheeler; B. L. Rushton; D. W. Nigg

    1988-01-01

    The PBF reactor at INEL has been redesigned for BNCT treatment of Gliobiastoma Multiforme. Analysis indicates that the design goals of 1.0E + 10 n\\/cm²{center dot}s epithermal neutron flux at the beam port can be met without exceeding the design goals of 2.6E -11 J cGy\\/(n\\/cm²) for the fast neutron KERMA and 2.0E-11 cGy\\/(n\\/cm²) for the gamma KERMA. These design

  10. Facility for non-destructive analysis for major and trace elements using neutron-capture gamma-ray spectrometry

    Microsoft Academic Search

    D. L. Anderson; M. P. Failey; W. H. Zoller; W. B. Walters; G. E. Gordon; R. M. Lindstrom

    1981-01-01

    A facility for neutron-capture ?-ray spectroscopy for analytical purposes has been developed and tested at the National Bureau\\u000a of Standards reactor. The system consists of an internal beam tube with collimators, an external beam tube and irradiation\\u000a station, a Compton-suppressed Ge(Li) ?-ray detection system, and a minicomputer-based data-collection and-analysis system.\\u000a Detection limits have been established for many elements and errors

  11. Neutron capture time scale of the s-process, estimated from s-process krypton in a meteorite

    NASA Technical Reports Server (NTRS)

    Matsuda, J.-I.; Lewis, R. S.; Anders, E.

    1980-01-01

    A krypton fraction enriched in s-process isotopes was extracted from a mineral fraction of the Murchison C2 chondrite. The (Kr-86)/(Kr-84) ratio is enhanced by 6 standard deviations, showing that significant amounts of Kr-86 were made in the s-process, despite the short, 10.8 yr beta-decay half-life of its precursor, Kr-85. Judging from this sample, the mean neutron capture time in the s-process was on the order of 5-100 yr for nuclei with cross sections of 125 mb.

  12. Molecular Medicine: Synthesis and In Vivo Detection of Agents for use in Boron Neutron Capture Therapy. Final Report

    SciTech Connect

    Kabalka, G. W.

    2005-06-28

    The primary objective of the project was the development of in vivo methods for the detection and evaluation of tumors in humans. The project was focused on utilizing positron emission tomography (PET) to monitor the distribution and pharamacokinetics of a current boron neutron capture therapy (BNCT) agent, p-boronophenylalanine (BPA) by labeling it with a fluorine-18, a positron emitting isotope. The PET data was then used to develop enhanced treatment planning protocols. The study also involved the synthesis of new tumor selective BNCTagents that could be labeled with radioactive nuclides for the in vivo detection of boron.

  13. User's manual of a supporting system for treatment planning in boron neutron capture therapy. JAERI computational dosimetry system

    E-print Network

    Kumada, H

    2002-01-01

    A boron neutron capture therapy (BNCT) with epithermal neutron beam is expected to treat effectively for malignant tumor that is located deeply in the brain. It is indispensable to estimate preliminarily the irradiation dose in the brain of a patient in order to perform the epithermal neutron beam BNCT. Thus, the JAERI Computational Dosimetry System (JCDS), which can calculate the dose distributions in the brain, has been developed. JCDS is a software that creates a 3-dimensional head model of a patient by using CT and MRI images and that generates a input data file automatically for calculation neutron flux and gamma-ray dose distribution in the brain by the Monte Carlo code: MCNP, and that displays the dose distribution on the head model for dosimetry by using the MCNP calculation results. JCDS has any advantages as follows; By treating CT data and MRI data which are medical images, a detail three-dimensional model of patient's head is able to be made easily. The three-dimensional head image is editable to ...

  14. Neutron-capture Nucleosynthesis in the He-Flash Convective Zone in Extremely Metal-Poor Stars

    SciTech Connect

    Nishimura, Takanori; Fujimoto, Masayuki Y. [Graduate School of Science, Hokkaido University, Kita-ku, Sapporo 060-0810 (Japan); Iwamoto, Nobuyuki [Nuclear Data Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Suda, Takuma [Meme Media Laboratory, Hokkaido University, Kita-ku, Sapporo 060-0810 (Japan); Aikawa, Masayuki [Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles, Campus de la Plaine, CP226, 1050 Brussels (Belgium); Iben, Icko Jr. [Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

    2006-07-12

    We investigate the nucleosynthesis in the helium flash convective zone, triggered by the hydrogen mixing, for extremely metal-poor stars of low and intermediate mass. Mixed hydrogen is converted into neutron through 12C(p,{gamma})13N(e+{nu})13C({alpha},n)16O and the doubly neutron-recycling reactions 12C(n,{gamma})13C({alpha},n)16O(n,{gamma})17O({alpha},n)20Ne operate. In addition to oxygen and neon, not only light elements from sodium through phosphorus but also the s-process elements, heavier than iron, are synthesized via successive neutron captures with 20Ne as seeds even in the stars originally devoid of metals. We follow the both the doubly neutron-recycling reactions and the s-process nucleosynthesis up to Pb and Bi by varying model parameters such as the amount of mixed 13C. The resultant abundance patterns is shown to reproduce the observed enhancement not only of oxygen, the light elements but also Sr observed from HE 0107-5240 and HE 1327-2326.

  15. RBEs of thermal neutron capture therapy and 10B(n, alpha)7 Li reaction on melanoma-bearing hamsters

    SciTech Connect

    Hiratsuka, J.; Kono, M.; Mishima, Y. (Kobe Univ. School of Medicine (Japan))

    1989-07-01

    Using Greene's melanoma transplanted into Syrian (golden) hamsters, we determined the relative biological effectiveness (RBE) of thermal neutron capture therapy (TNCT) using 10B-paraboronophenylalanine (10B-BPA) in comparison with a 9-MeV electron beam. We also obtained the RBE of the 10B(n, alpha)7 Li reaction by calculation based on summed dose data from TNCT. Throughout this study, the Kyoto University Research Reactor was used as the source for thermal neutrons; the reactor was specially altered to attain a low contamination level both for gamma-rays and fast neutrons. 10B-BPA was administered 8 hours before thermal neutron irradiation to the hamsters with melanoma. The tumor was then irradiated at 5 MW for 90 minutes. The absorbed dose from this TNCT was calculated by the method of Fairchild and Goodman. The RBEs of the TNCT and the 10B(n, alpha)7 Li reaction obtained by the tumor growth delay time (TGDT) method were 2.22 and 2.51, respectively, at 10.5 days of TGDT. These RBE values varied with TGDT and the absorbed dose. The RBE value of TNCT had a peak at 7.0 days of TGDT; that of the 10B(n, alpha)7Li reaction was higher at a low absorbed dose level and lower at a high absorbed dose level.

  16. Accelerator-Based Boron Neutron Capture Therapy and the Development of a Dedicated Tandem-Electrostatic-Quadrupole

    NASA Astrophysics Data System (ADS)

    Kreiner, A. J.; Di Paolo, H.; Burlon, A. A.; Kesque, J. M.; Valda, A. A.; Debray, M. E.; Giboudot, Y.; Levinas, P.; Fraiman, M.; Romeo, V.; Somacal, H. R.; Minsky, D. M.

    2007-10-01

    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 7Li(p,n)7Be 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 7Li(p,n)7Be 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.

  17. Boron neutron capture therapy induces cell cycle arrest and cell apoptosis of glioma stem/progenitor cells in vitro

    PubMed Central

    2013-01-01

    Background Glioma stem cells in the quiescent state are resistant to clinical radiation therapy. An almost inevitable glioma recurrence is due to the persistence of these cells. The high linear energy transfer associated with boron neutron capture therapy (BNCT) could kill quiescent and proliferative cells. Methods The present study aimed to evaluate the effects of BNCT on glioma stem/progenitor cells in vitro. The damage induced by BNCT was assessed using cell cycle progression, apoptotic cell ratio and apoptosis-associated proteins expression. Results The surviving fraction and cell viability of glioma stem/progenitor cells were decreased compared with differentiated glioma cells using the same boronophenylalanine pretreatment and the same dose of neutron flux. BNCT induced cell cycle arrest in the G2/M phase and cell apoptosis via the mitochondrial pathway, with changes in the expression of associated proteins. Conclusions Glioma stem/progenitor cells, which are resistant to current clinical radiotherapy, could be effectively killed by BNCT in vitro via cell cycle arrest and apoptosis using a prolonged neutron irradiation, although radiosensitivity of glioma stem/progenitor cells was decreased compared with differentiated glioma cells when using the same dose of thermal neutron exposure and boronophenylalanine pretreatment. Thus, BNCT could offer an appreciable therapeutic advantage to prevent tumor recurrence, and may become a promising treatment in recurrent glioma. PMID:23915425

  18. Synthesis, characterization and biological evaluation of carboranylmethylbenzo[b]acridones as novel agents for boron neutron capture therapy.

    PubMed

    da Silva, A Filipa F; Seixas, Raquel S G R; Silva, Artur M S; Coimbra, Joana; Fernandes, Ana C; Santos, Joana P; Matos, António; Rino, José; Santos, Isabel; Marques, Fernanda

    2014-07-28

    Herein we present the synthesis and characterization of benzo[b]acridin-12(7H)-ones bearing carboranyl moieties and test their biological effectiveness as boron neutron capture therapy (BNCT) agents in cancer treatment. The cellular uptake of these novel compounds into the U87 human glioblastoma cells was evaluated by boron analysis (ICP-MS) and by fluorescence imaging (confocal microscopy). The compounds enter the U87 cells exhibiting a similar profile, i.e., preferential accumulation in the cytoskeleton and membranes and a low cytotoxic activity (IC50 values higher than 200 ?M). The cytotoxic activity and cellular morphological alterations after neutron irradiation in the Portuguese Research Reactor (6.6 × 10(7) neutrons cm(-2) s(-1), 1 MW) were evaluated by the MTT assay and by electron microscopy (TEM). Post-neutron irradiation revealed that BNCT has a higher cytotoxic effect on the cells. Accumulation of membranous whorls in the cytoplasm of cells treated with one of the compounds correlates well with the cytotoxic effect induced by radiation. Results provide a strong rationale for considering one of these compounds as a lead candidate for a new generation of BNCT agents. PMID:24915168

  19. MANTRA: An Integral Reactor Physics Experiment to Infer the Neutron Capture Cross Sections of Actinides and Fission Products in Fast and Epithermal Spectra

    NASA Astrophysics Data System (ADS)

    Youinou, G.; Vondrasek, R.; Veselka, H.; Salvatores, M.; Paul, M.; Pardo, R.; Palmiotti, G.; Palchan, T.; Nusair, O.; Nimmagadda, J.; Nair, C.; Murray, P.; Maddock, T.; Kondrashev, S.; Kondev, F. G.; Jones, W.; Imel, G.; Glass, C.; Fonnesbeck, J.; Berg, J.; Bauder, W.

    2014-05-01

    This paper presents an update of an on-going collaborative INL-ANL-ISU integral reactor physics experiment whose objective is to infer the effective neutron capture cross sections for most of the actinides of importance for reactor physics and fuel cycle studies in both fast and epithermal spectra. Some fission products are also being considered. The principle of the experiment is to irradiate very pure actinide samples in the Advanced Test Reactor at INL and, after a given time, determine the amount of the different transmutation products. The determination of the nuclide densities before and after neutron irradiation together with the neutron fluence will allow inference of effective neutron capture cross-sections in different neutron spectra.

  20. Compact D-D Neutron Source-Driven Subcritical Multiplier and Beam-Shaping Assembly for Boron Neutron Capture Therapy

    SciTech Connect

    Francesco Ganda; Jasmina Vujic; Ehud Greenspan; Ka-Ngo Leung

    2010-12-01

    This work assesses the feasibility of using a small, safe, and inexpensive keff 0.98 subcritical fission assembly [subcritical neutron multiplier (SCM)] to amplify the treatment neutron beam intensity attainable from a compact deuterium-deuterium (D-D) fusion neutron source delivering [approximately]1012 n/s. The objective is to reduce the treatment time for deep-seated brain tumors to [approximately]1 h. The paper describes the optimal SCM design and two optimal beam-shaping assemblies (BSAs) - one designed to maximize the dose rate and the other designed to maximize the total dose that can be delivered to a deep-seated tumor. The neutron beam intensity amplification achieved with the optimized SCM and BSA results in an increase in the treatment dose rate by a factor of 18: from 0.56 Gy/h without the SCM to 10.1 Gy/h. The entire SCM is encased in an aluminum structure. The total amount of 20% enriched uranium required for the SCM is 8.5 kg, and the cost (not including fabrication) is estimated to be less than $60,000. The SCM power level is estimated at 400 W when driven by a 1012 n/s D-D neutron source. This translates into consumption of only [approximately]0.6% of the initially loaded 235U atoms during 50 years of continuous operation and implies that the SCM could operate continuously for the entire lifetime of the facility without refueling. Cooling the SCM does not pose a challenge; it may be accomplished by natural circulation as the maximum heat flux is only 0.034 W/cm2.

  1. Boron neutron capture therapy using mixed epithermal and thermal neutron beams in patients with malignant glioma-correlation between radiation dose and radiation injury and clinical outcome

    SciTech Connect

    Kageji, Teruyoshi [Department of Neurosurgery, Graduate School of Health Biosciences, University of Tokushima, Tokushima (Japan)]. E-mail: kageji@clin.med.tokushima-u.ac.jp; Nagahiro, Shinji [Department of Neurosurgery, Graduate School of Health Biosciences, University of Tokushima, Tokushima (Japan); Matsuzaki, Kazuhito [Department of Neurosurgery, Graduate School of Health Biosciences, University of Tokushima, Tokushima (Japan); Mizobuchi, Yoshifumi [Department of Neurosurgery, Graduate School of Health Biosciences, University of Tokushima, Tokushima (Japan); Toi, Hiroyuki [Department of Neurosurgery, Graduate School of Health Biosciences, University of Tokushima, Tokushima (Japan); Nakagawa, Yoshinobu [Department of Neurosurgery, National Kagawa Children's Hospital, Kagawa (Japan); Kumada, Hiroaki [Department of Research Reactor, Tokai Research Establishment, Japan Atomic Energy Research Institute, Ibaragi (Japan)

    2006-08-01

    Purpose: To clarify the correlation between the radiation dose and clinical outcome of sodium borocaptate-based intraoperative boron neutron capture therapy in patients with malignant glioma. Methods and Materials: The first protocol (P1998, n = 8) prescribed a maximal gross tumor volume (GTV) dose of 15 Gy. In 2001, a dose-escalated protocol was introduced (P2001, n 11), which prescribed a maximal vascular volume dose of 15 Gy or, alternatively, a clinical target volume (CTV) dose of 18 Gy. Results: The GTV and CTV doses in P2001 were 1.1-1.3 times greater than those in P1998. The maximal vascular volume dose of those with acute radiation injury was 15.8 Gy. The mean GTV and CTV dose in long-term survivors with glioblastoma was 26.4 and 16.5 Gy, respectively. A statistically significant correlation between the GTV dose and median survival time was found. In the 11 glioblastoma patients in P2001, the median survival time was 19.5 months and 1- and 2-year survival rate was 60.6% and 37.9%, respectively. Conclusion: Dose escalation contributed to the improvement in clinical outcome. To avoid radiation injury, the maximal vascular volume dose should be <12 Gy. For long-term survival in patients with glioblastoma after boron neutron capture therapy, the optimal mean dose of the GTV and CTV was 26 and 16 Gy, respectively.

  2. Power Burst Facility/Boron Neutron Capture Therapy Program for cancer treatment

    SciTech Connect

    Ackermann, A.L. (ed.); Dorn, R.V. III.

    1990-09-01

    This monthly bulletin describes activities in the following project areas during this reporting period: supporting technology development, large animal model studies, neutron source and facility preparation, administration and common support, and PBF operations. (FI)

  3. The abilities of LiF thermoluminescent detectors for dosimetry at boron neutron capture therapy beams

    Microsoft Academic Search

    M. Toivonen; V. Chernov; H. Jungner; C. Aschan; A. Toivonen

    1998-01-01

    Thermoluminescent detectors based on natural LiF are sensitive to epithermal and thermal neutrons of BNCT beams. A sensitivity reduction by a factor of 10–20 is necessary to keep the response of LiF:Mg,Ti detectors in the linear dose range. This reduction does not increase significantly the random uncertainties of gamma and neutron dose measurements (standard deviation ?3.5 and 7%, respectively) when

  4. Thermal-neutron scattering lengths and capture by even calcium isotopes

    Microsoft Academic Search

    S. Raman; S. Kahane; R. M. Moon; J. A. Fernandez-Baca; J. L. Zarestky; J. E. Lynn; Richardson J. W. Jr

    1989-01-01

    Neutron-diffraction patterns have been measured for isotopically enriched powder samples of calcite using both steady-state and pulsed-neutron techniques. Greatly enhanced precision over previous work has been achieved for ⁴°Ca and ⁴⁴Ca, while the results for ⁴²Ca, ⁴³Ca, and ⁴⁸Ca represent new data. The coherent scattering lengths deduced from these measurements have been employed in a more definitive analysis of primary

  5. Unblocking of the Gamow-Teller strength in stellar electron capture on neutron-rich germanium isotopes

    SciTech Connect

    Langanke, K.; Kolbe, E.; Dean, D. J.

    2001-03-01

    We propose a new model to calculate stellar electron capture rates for neutron-rich nuclei. These nuclei are encountered in the core collapse of a massive star. Using the shell model Monte Carlo approach, we first calculate the finite temperature occupation numbers in the parent nucleus. We then use these occupation numbers as a starting point for calculations using the random phase approximation (RPA). Using the RPA approach, we calculate electron capture rates including both allowed and forbidden transitions. Such a hybrid model is particularly useful for nuclei with proton numbers Z<40 and neutron numbers N>40, where allowed Gamow-Teller transitions are only possible due to configuration mixing by the residual interaction and by thermal unblocking of pf-shell single-particle states. Using the even germanium isotopes {sup 68-76}Ge as examples, we demonstrate that the configuration mixing is strong enough to unblock the Gamow-Teller transitions at all temperatures relevant to core-collapse supernovae.

  6. Demonstration of three-dimensional deterministic radiation transport theory dose distribution analysis for boron neutron capture therapy.

    PubMed

    Nigg, D W; Randolph, P D; Wheeler, F J

    1991-01-01

    The Monte Carlo stochastic simulation technique has traditionally been the only well-recognized method for computing three-dimensional radiation dose distributions in connection with boron neutron capture therapy (BNCT) research. A deterministic approach to this problem would offer some advantages over the Monte Carlo method. This paper describes an application of a deterministic method to analytically simulate BNCT treatment of a canine head phantom using the epithermal neutron beam at the Brookhaven medical research reactor (BMRR). Calculations were performed with the TORT code from Oak Ridge National Laboratory (ORNL), an implementation of the discrete ordinates, or Sn method. Calculations were from first principles and used no empirical correction factors. The phantom surface was modeled by flat facets of approximately 1 cm2. The phantom interior was homogeneous. Energy-dependent neutron and photon scalar fluxes were calculated on a 32 x 16 x 22 mesh structure with 96 discrete directions in angular phase space. The calculation took 670 min on an Apollo DN10000 workstation. The results were subsequently integrated over energy to obtain full three-dimensional dose distributions. Isodose contours and depth-dose curves were plotted for several separate dose components of interest. Phantom measurements were made by measuring neutron activation (and therefore neutron flux) as a function of depth in copper-gold alloy wires that were inserted through catheters placed in holes drilled in the phantom. Measurements agreed with calculations to within about 15%. The calculations took about an order of magnitude longer than comparable Monte Carlo calculations but provided various conveniences, as well as a useful check. PMID:1901131

  7. Specification of the physical and biologically effective absorbed dose in radiation therapies utilizing the boron neutron capture reaction

    NASA Astrophysics Data System (ADS)

    Burmeister, Jay William

    Boron Neutron Capture Therapy (BNCT) is a promising bimodal radiation therapy used primarily for highly malignant gliomas. Specification of the absorbed and biologically effective dose in BNCT is a primary concern in the implementation of this therapeutic technique. Providing accurate dosimetry for the complex mixed field encountered in BNCT and understanding the microscopic nature of the absorbed dose are of paramount importance. This work will address issues concerning the dosimetry of BNCT, offering a method to accurately obtain the absorbed dose and a framework for understanding its biological effectiveness. The rationale for microdosimetry as well as its advantages for BNCT dosimetry are considered. A dual miniature tissue-equivalent proportional counter (TEPC) technique is introduced as a tool for microdosimetry of the BNC reaction. A detailed outline of the design, construction, characterization, and calibration of the miniature TEPCs is provided. Dosimetric characterization of a 252Cf radiation field and a d(48.5)+Be fast neutron therapy beam using the miniature TEPCs is also presented. Furthermore, a compilation of data collected in clinical BNCT beams at the Brookhaven National Laboratory and the Massachusetts Institute of Technology is given. This work also furnishes an intercomparison of the radiation quality and beam characteristics of these two BNCT facilities. In addition, an outline of the potential enhancement of fast neutron therapy using the BNC reaction is presented. Methods for beam modification as well as dosimetric results for the modified beam are reviewed. An ionization chamber-based method designed for BNC dosimetry of the modified fast neutron beam is also introduced. Design, construction, calibration and characterization of the ion chambers are examined, as well as a comparison of results with other dosimetry methods. The significance of these dosimetry methods for neutron beams used for radiation therapy is discussed.

  8. In situ elemental analysis using neutron-capture gamma-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Evans, Larry G.; Lapides, Jeffrey R.; Trombka, Jacob I.; Jensen, Dal H.

    In situ chemical analysis has become increasingly important in many areas of geochemical exploration and environmental monitoring. However, the determination of absolute or relative concentrations by neutron-gamma techniques can be difficult because of the variety of materials that can be encountered. Changes in concentration of neutron moderators, particularly water, and of strong absorbers, such as iron, can result in spatial and energy distribution variations of the neutron flux in the material. These lead to changes in the measured gamma-ray spectrum. We have been developing analytical procedures which allow the absolute and relative abundances of major and minor elements to be determined from the measured neutron-induced gamma-ray spectrum. Calculations are made using the one-dimensional neutron and gamma transport code ANISN. From the calculations, conversion factors are obtained that can be used to convert gamma-ray count rates to elemental concentrations. Once these conversion factors are determined as a function of water content and the macroscopic cross section, they can be used to determine compositions of unknown samples. To explore the application of these analytical methods, a number of different experimental test programs have been initiated to collect measured gamma-ray spectra. Field tests have been conducted in soils of various compositions using a 120 cm 3 HPGe detector and a 14 MeV pulsed neutron generator.

  9. Study of boron neutron capture therapy used neutron source with protons bombarding a thick 9Be target.

    PubMed

    Yue, G; Chen, J; Song, R

    1997-06-01

    Neutron sources created by 4-, 3.5-, and 3-MeV protons striking a thick beryllium target were studied via the time-of-flight technique. Protons were accelerated by the Peking University 4.5 MV electrostatic accelerator. Two disk-shaped 9Be targets with thickness 1.5 and 3 mm were used in the measurements. The time-of-flight spectra were observed at zero degrees with respect to the incident proton beam. The analysis to these time-of-flight spectra is given. The time-of-flight spectra were converted to the energy spectra and compared to a neutron spectrum of 7Li(p, n)7 Be reaction with incident energy 2.5 MeV, which was also measured in this work. Restricted by the spectrometer itself, the threshold of the measurements is 400 keV. The results show that by using several MeV protons bombarding a thick beryllium target, reactions other than 9Be(p, n)9B produce significant contributions to the neutron yield with energy less than 1 MeV. PMID:9198018

  10. Neutron capture on Pt isotopes in iron meteorites and the Hf-W chronology of core formation in planetesimals

    NASA Astrophysics Data System (ADS)

    Kruijer, Thomas S.; Fischer-Gödde, Mario; Kleine, Thorsten; Sprung, Peter; Leya, Ingo; Wieler, Rainer

    2013-01-01

    The short-lived 182Hf-182W isotope system can provide powerful constraints on the timescales of planetary core formation, but its application to iron meteorites is hampered by neutron capture reactions on W isotopes resulting from exposure to galactic cosmic rays. Here we show that Pt isotopes in magmatic iron meteorites are also affected by capture of (epi)thermal neutrons and that the Pt isotope variations are correlated with variations in 182W/184W. This makes Pt isotopes a sensitive neutron dosimeter for correcting cosmic ray-induced W isotope shifts. The pre-exposure 182W/184W derived from the Pt-W isotope correlations of the IID, IVA and IVB iron meteorites are higher than most previous estimates and are more radiogenic than the initial 182W/184W of Ca-Al-rich inclusions (CAI). The Hf-W model ages for core formation range from +1.6±1.0 million years (Ma; for the IVA irons) to +2.7±1.3 Ma after CAI formation (for the IID irons), indicating that there was a time gap of at least ˜1 Ma between CAI formation and metal segregation in the parent bodies of some iron meteorites. From the Hf-W ages a time limit of <1.5-2 Ma after CAI formation can be inferred for the accretion of the IID, IVA and IVB iron meteorite parent bodies, consistent with earlier conclusions that the accretion of differentiated planetesimals predated that of most chondrite parent bodies.

  11. Neutron transmission and capture measurements and analysis of /sup 60/Ni from 1 to 450 keV

    SciTech Connect

    Perey, C.M.; Harvey, J.A.; Macklin, R.L.; Winters, R.R.; Perey, F.G.

    1982-11-01

    High-resolution transmission and capture measurements of /sup 60/Ni-enriched targets have been made at the Oak Ridge Electron Linear Accelerator (ORELA) from a few eV to 1800 keV in transmission and from 2.5 keV to 5 MeV in capture . The transmission data from 1 to 450 keV were analyzed with a multi-level R-matrix code which uses the Bayes' theorem for the fitting process. This code provides the energies and neutron widths of the resonances inside the 1- to 450-keV region as well as a possible parameterization for outside resonances to describe the smooth cross section in this region. The capture data were analyzed with a least-squares fitting code using the Breit-Wigner formula. From 2.5 to 450 keV, 166 resonances were seen in both sets of data. Correspondence between the energy scales shows a discontinuity around 300 keV which makes the matching of resonances at higher energies difficult. Eighty-nine resonances were seen in the capture data only. Average parameters for the 30 observed s-wave resonances were deduced. The average level spacing D/sub 0/ was found to be equal to 15.2 +- 1.5 keV, the strength function, S/sub 0/, equal to (2.2 +- 0.6) x 10/sup -4/ and the average radiation width, GAMMA/sub ..gamma../, equal to 1.30 +- 0.07 eV. The staircase plot of the reduced level widths and the plot of the Lorentz-weighted strength function averaged over various energy intervals show possible evidence for doorway states. The level densities calculated with the Fermi-gas model for l = 0 and for l > 0 resonances were compared with the cumulative number of observed resonances, but the analysis is not conclusive. The average capture cross section as a function of the neutron incident energy is compared to the tail of the giant electric dipole resonance prediction.

  12. Current status of boron neutron capture therapy of high grade gliomas and recurrent head and neck cancer

    PubMed Central

    2012-01-01

    Boron neutron capture therapy (BNCT) is a biochemically targeted radiotherapy based on the nuclear capture and fission reactions that occur when non-radioactive boron-10, which is a constituent of natural elemental boron, is irradiated with low energy thermal neutrons to yield high linear energy transfer alpha particles and recoiling lithium-7 nuclei. Clinical interest in BNCT has focused primarily on the treatment of high grade gliomas, recurrent cancers of the head and neck region and either primary or metastatic melanoma. Neutron sources for BNCT currently have been limited to specially modified nuclear reactors, which are or until the recent Japanese natural disaster, were available in Japan, the United States, Finland and several other European countries, Argentina and Taiwan. Accelerators producing epithermal neutron beams also could be used for BNCT and these are being developed in several countries. It is anticipated that the first Japanese accelerator will be available for therapeutic use in 2013. The major hurdle for the design and synthesis of boron delivery agents has been the requirement for selective tumor targeting to achieve boron concentrations in the range of 20??g/g. This would be sufficient to deliver therapeutic doses of radiation with minimal normal tissue toxicity. Two boron drugs have been used clinically, a dihydroxyboryl derivative of phenylalanine, referred to as boronophenylalanine or “BPA”, and sodium borocaptate or “BSH” (Na2B12H11SH). In this report we will provide an overview of other boron delivery agents that currently are under evaluation, neutron sources in use or under development for BNCT, clinical dosimetry, treatment planning, and finally a summary of previous and on-going clinical studies for high grade gliomas and recurrent tumors of the head and neck region. Promising results have been obtained with both groups of patients but these outcomes must be more rigorously evaluated in larger, possibly randomized clinical trials. Finally, we will summarize the critical issues that must be addressed if BNCT is to become a more widely established clinical modality for the treatment of those malignancies for which there currently are no good treatment options. PMID:22929110

  13. Current status of boron neutron capture therapy of high grade gliomas and recurrent head and neck cancer.

    PubMed

    Barth, Rolf F; Vicente, M Graca H; Harling, Otto K; Kiger, W S; Riley, Kent J; Binns, Peter J; Wagner, Franz M; Suzuki, Minoru; Aihara, Teruhito; Kato, Itsuro; Kawabata, Shinji

    2012-01-01

    Boron neutron capture therapy (BNCT) is a biochemically targeted radiotherapy based on the nuclear capture and fission reactions that occur when non-radioactive boron-10, which is a constituent of natural elemental boron, is irradiated with low energy thermal neutrons to yield high linear energy transfer alpha particles and recoiling lithium-7 nuclei. Clinical interest in BNCT has focused primarily on the treatment of high grade gliomas, recurrent cancers of the head and neck region and either primary or metastatic melanoma. Neutron sources for BNCT currently have been limited to specially modified nuclear reactors, which are or until the recent Japanese natural disaster, were available in Japan, United States, Finland and several other European countries, Argentina and Taiwan. Accelerators producing epithermal neutron beams also could be used for BNCT and these are being developed in several countries. It is anticipated that the first Japanese accelerator will be available for therapeutic use in 2013. The major hurdle for the design and synthesis of boron delivery agents has been the requirement for selective tumor targeting to achieve boron concentrations in the range of 20 ?g/g. This would be sufficient to deliver therapeutic doses of radiation with minimal normal tissue toxicity. Two boron drugs have been used clinically, a dihydroxyboryl derivative of phenylalanine, referred to as boronophenylalanine or "BPA", and sodium borocaptate or "BSH" (Na2B12H11SH). In this report we will provide an overview of other boron delivery agents that currently are under evaluation, neutron sources in use or under development for BNCT, clinical dosimetry, treatment planning, and finally a summary of previous and on-going clinical studies for high grade gliomas and recurrent tumors of the head and neck region. Promising results have been obtained with both groups of patients but these outcomes must be more rigorously evaluated in larger, possibly randomized clinical trials. Finally, we will summarize the critical issues that must be addressed if BNCT is to become a more widely established clinical modality for the treatment of those malignancies for which there currently are no good treatment options. PMID:22929110

  14. Tidal capture of a primordial black hole by a neutron star: implications for constraints on dark matter

    NASA Astrophysics Data System (ADS)

    Pani, Paolo; Loeb, Abraham

    2014-06-01

    In a close encounter with a neutron star, a primordial black hole can get gravitationally captured by depositing a considerable amount of energy into nonradial stellar modes of very high angular number l. If the neutron-star equation of state is sufficiently stiff, we show that the total energy loss in the point-particle approximation is formally divergent. Various mechanisms — including viscosity, finite-size effects and the elasticity of the crust — can damp high-l modes and regularize the total energy loss. Within a short time, the black hole is trapped inside the star and disrupts it by rapid accretion. Estimating these effects, we predict that the existence of old neutron stars in regions where the dark-matter density ?DMgtrsim102(?/km s-1) GeV cm-3 (where ? is the dark-matter velocity dispersion) limits the abundance of primordial black holes in the mass range 1017 glesssimmPBHlesssim1024 g, which was previously unconstrained. In combination with existing limits, our results suggest that primordial black holes cannot be the dominant dark matter constituent.

  15. Estimation of relative biological effectiveness for boron neutron capture therapy using the PHITS code coupled with a microdosimetric kinetic model.

    PubMed

    Horiguchi, Hironori; Sato, Tatsuhiko; Kumada, Hiroaki; Yamamoto, Tetsuya; Sakae, Takeji

    2015-03-01

    The absorbed doses deposited by boron neutron capture therapy (BNCT) can be categorized into four components: ? and (7)Li particles from the (10)B(n, ?)(7)Li reaction, 0.54-MeV protons from the (14)N(n, p)(14)C reaction, the recoiled protons from the (1)H(n, n) (1)H reaction, and photons from the neutron beam and (1)H(n, ?)(2)H reaction. For evaluating the irradiation effect in tumors and the surrounding normal tissues in BNCT, it is of great importance to estimate the relative biological effectiveness (RBE) for each dose component in the same framework. We have, therefore, established a new method for estimating the RBE of all BNCT dose components on the basis of the microdosimetric kinetic model. This method employs the probability density of lineal energy, y, in a subcellular structure as the index for expressing RBE, which can be calculated using the microdosimetric function implemented in the particle transport simulation code (PHITS). The accuracy of this method was tested by comparing the calculated RBE values with corresponding measured data in a water phantom irradiated with an epithermal neutron beam. The calculation technique developed in this study will be useful for biological dose estimation in treatment planning for BNCT. PMID:25428243

  16. Proton nuclear magnetic resonance measurement of p-boronophenylalanine (BPA): A therapeutic agent for boron neutron capture therapy

    PubMed Central

    Zuo, C. S.; Prasad, P. V.; Busse, Paul; Tang, L.; Zamenhof, R. G.

    2015-01-01

    Noninvasive in vivo quantitation of boron is necessary for obtaining pharmacokinetic data on candidate boronated delivery agents developed for boron neutron capture therapy (BNCT). Such data, in turn, would facilitate the optimization of the temporal sequence of boronated drug infusion and neutron irradiation. Current approaches to obtaining such pharmacokinetic data include: positron emission tomography employing F-18 labeled boronated delivery agents (e.g., p-boronophenylalanine), ex vivo neutron activation analysis of blood (and very occasionally tissue) samples, and nuclear magnetic resonance (NMR) techniques. In general, NMR approaches have been hindered by very poor signal to noise achieved due to the large quadrupole moments of B-10 and B-11 and (in the case of B-10) very low gyromagnetic ratio, combined with low physiological concentrations of these isotopes under clinical conditions. This preliminary study examines the feasibility of proton NMR spectroscopy for such applications. We have utilized proton NMR spectroscopy to investigate the detectability of p-boronophenylalanine fructose (BPA-f) at typical physiological concentrations encountered in BNCT. BPA-f is one of the two boron delivery agents currently undergoing clinical phase-I/II trials in the U.S., Japan, and Europe. This study includes high-resolution 1H spectroscopic characterization of BPA-f to identify useful spectral features for purposes of detection and quantification. The study examines potential interferences, demonstrates a linear NMR signal response with concentration, and presents BPA NMR spectra in ex vivo blood samples and in vivo brain tissues. PMID:10435522

  17. A New Signal Processing Technique for Neutron Capture Cross Section Measurement Based on Pulse Width Analysis

    NASA Astrophysics Data System (ADS)

    Katabuchi, T.; Matsuhashi, T.; Terada, K.; Mizumoto, M.; Hirose, K.; Kimura, A.; Furutaka, K.; Hara, K. Y.; Harada, H.; Hori, J.; Igashira, M.; Kamiyama, T.; Kitatani, F.; Kino, K.; Kiyanagi, Y.; Koizumi, M.; Nakamura, S.; Oshima, M.; Toh, Y.

    2014-05-01

    A fast data acquisition method based on pulse width analysis was developed for ?-ray spectroscopy with an NaI(Tl) detector. The new method was tested in experiments with standard ?-ray sources and pulsed neutron beam from a spallation neutron source. Pulse height spectra were successfully reconstructed from pulse width distribution by use of an energy calibration curve. The 197Au(n, ?)198Au cross section was measured by this method to test the viability. The obtained experimental cross section showed a good agreement with a calculation using the resonance parameters of JENDL-4.0.

  18. Measurement of neutron capture cross section of Li-7 at J-PARC / MLF / ANNRI

    SciTech Connect

    Makii, H.; Ota, S.; Nishinaka, I.; Nishio, I. [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Segawa, M.; Kimura, A.; Harada, H. [Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 391-1195 (Japan)

    2014-05-02

    We have measured the {sup 7}Li(n,?){sup 8}Li reaction at Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) installed at the Material and Life science experimental Facility in the Japan Proton Accelerator Research Complex (J-PARC / MLF). In this experiment, we used intense pulsed neutron beam provided by J-PARC / MLF and high performance Ge spectrometer, which is one of the main detectors of the ANNRI. We clearly detected ? rays from the {sup 7}Li(n,?){sup 8}Li reaction with sufficient signal-to-noise ratio.

  19. Fission fragment mass and energy distributions as a function of incident neutron energy measured in a lead slowing-down spectrometer

    SciTech Connect

    Romano, C.; Danon, Y.; Block, R.; Thompson, J.; Blain, E. [Rensselaer Polytechnic Institute, Department of Mechanical, Aerospace, and Nuclear Engineering, NES 1-25, 110 8th Street, Troy, New York 12180 (United States); Bond, E. [Los Alamos National Lab, Los Alamos, New Mexico 87545 (United States)

    2010-01-15

    A new method of measuring fission fragment mass and energy distributions as a function of incident neutron energy in the range from below 0.1 eV to 1 keV has been developed. The method involves placing a double-sided Frisch-gridded fission chamber in Rensselaer Polytechnic Institute's lead slowing-down spectrometer (LSDS). The high neutron flux of the LSDS allows for the measurement of the energy-dependent, neutron-induced fission cross sections simultaneously with the mass and kinetic energy of the fission fragments of various small samples. The samples may be isotopes that are not available in large quantities (submicrograms) or with small fission cross sections (microbarns). The fission chamber consists of two anodes shielded by Frisch grids on either side of a single cathode. The sample is located in the center of the cathode and is made by depositing small amounts of actinides on very thin films. The chamber was successfully tested and calibrated using 0.41+-0.04 ng of {sup 252}Cf and the resulting mass distributions were compared to those of previous work. As a proof of concept, the chamber was placed in the LSDS to measure the neutron-induced fission cross section and fragment mass and energy distributions of 25.3+-0.5 mug of {sup 235}U. Changes in the mass distributions as a function of incident neutron energy are evident and are examined using the multimodal fission mode model.

  20. Fission fragment mass and energy distributions as a function of incident neutron energy measured in a lead slowing-down spectrometer

    NASA Astrophysics Data System (ADS)

    Romano, C.; Danon, Y.; Block, R.; Thompson, J.; Blain, E.; Bond, E.

    2010-01-01

    A new method of measuring fission fragment mass and energy distributions as a function of incident neutron energy in the range from below 0.1 eV to 1 keV has been developed. The method involves placing a double-sided Frisch-gridded fission chamber in Rensselaer Polytechnic Institute’s lead slowing-down spectrometer (LSDS). The high neutron flux of the LSDS allows for the measurement of the energy-dependent, neutron-induced fission cross sections simultaneously with the mass and kinetic energy of the fission fragments of various small samples. The samples may be isotopes that are not available in large quantities (submicrograms) or with small fission cross sections (microbarns). The fission chamber consists of two anodes shielded by Frisch grids on either side of a single cathode. The sample is located in the center of the cathode and is made by depositing small amounts of actinides on very thin films. The chamber was successfully tested and calibrated using 0.41±0.04 ng of Cf252 and the resulting mass distributions were compared to those of previous work. As a proof of concept, the chamber was placed in the LSDS to measure the neutron-induced fission cross section and fragment mass and energy distributions of 25.3±0.5?g of U235. Changes in the mass distributions as a function of incident neutron energy are evident and are examined using the multimodal fission mode model.