Sample records for recoil alpha particle

  1. Transport of Radioactive Material by Alpha Recoil

    SciTech Connect

    Icenhour, A.S.

    2005-05-19

    The movement of high-specific-activity radioactive particles (i.e., alpha recoil) has been observed and studied since the early 1900s. These studies have been motivated by concerns about containment of radioactivity and the protection of human health. Additionally, studies have investigated the potential advantage of alpha recoil to effect separations of various isotopes. This report provides a review of the observations and results of a number of the studies.

  2. A Method of Measuring Hydrogen Isotopes in Surface Layers of Planetary Soils by Spectroscopy of Recoil Protons in Alpha Particle Elastic Scattering

    Microsoft Academic Search

    B. N. Korchuganov; G. G. Dol'nikov; M. V. Gerasimov; O. F. Prilutskii; R. Rider; G. Waenke; T. Economou

    2004-01-01

    A theoretical and experimental feasibility study of possible determination of the hydrogen and deuterium concentrations in the surface layers of planetary bodies is presented. The method under study is the recoil proton and deuteron spectrometry of forward scattering in the course of elastic interaction of alpha particles with the nuclei of hydrogen isotopes. The spectra of recoil protons and deuterons

  3. Alpha Particle

    Microsoft Academic Search

    P. Murdin

    2000-01-01

    Term that is sometimes used to describe a helium nucleus, a positively charged particle that consists of two protons and two neutrons, bound together. Alpha particles, which were discovered by Ernest Rutherford (1871-1937) in 1898, are emitted by atomic nuclei that are undergoing alpha radioactivity. During this process, an unstable heavy nucleus spontaneously emits an alpha particle and transmut...

  4. Recoil-alpha-fission and recoil-alpha-alpha-fission events observed in the reaction Ca-48 + Am-243

    E-print Network

    U. Forsberg; D. Rudolph; L. -L. Andersson; A. Di Nitto; Ch. E. Düllmann; J. M. Gates; P. Golubev; K. E. Gregorich; C. J. Gross; R. -D. Herzberg; F. P. Hessberger; J. Khuyagbaatar; J. V. Kratz; K. Rykaczewski; L. G. Sarmiento; M. Schädel; A. Yakushev; S. Åberg; D. Ackermann; M. Block; H. Brand; B. G. Carlsson; D. Cox; X. Derkx; J. Dobaczewski; K. Eberhardt; J. Even; C. Fahlander; J. Gerl; E. Jäger; B. Kindler; J. Krier; I. Kojouharov; N. Kurz; B. Lommel; A. Mistry; C. Mokry; W. Nazarewicz; H. Nitsche; J. P. Omtvedt; P. Papadakis; I. Ragnarsson; J. Runke; H. Schaffner; B. Schausten; Y. Shi; P. Thörle-Pospiech; T. Torres; T. Traut; N. Trautmann; A. Türler; A. Ward; D. E. Ward; N. Wiehl

    2015-02-10

    Products of the fusion-evaporation reaction Ca-48 + Am-243 were studied with the TASISpec set-up at the gas-filled separator TASCA at the GSI Helmholtzzentrum f\\"ur Schwerionenforschung. Amongst the detected thirty correlated alpha-decay chains associated with the production of element Z=115, two recoil-alpha-fission and five recoil-alpha-alpha-fission events were observed. The latter are similar to four such events reported from experiments performed at the Dubna gas-filled separator. Contrary to their interpretation, we propose an alternative view, namely to assign eight of these eleven decay chains of recoil-alpha(-alpha)-fission type to start from the 3n-evaporation channel 115-288. The other three decay chains remain viable candidates for the 2n-evaporation channel 115-289.

  5. Recoil-alpha-fission and recoil-alpha-alpha-fission events observed in the reaction Ca-48 + Am-243

    E-print Network

    Forsberg, U; Andersson, L -L; Di Nitto, A; Düllmann, Ch E; Gates, J M; Golubev, P; Gregorich, K E; Gross, C J; Herzberg, R -D; Hessberger, F P; Khuyagbaatar, J; Kratz, J V; Rykaczewski, K; Sarmiento, L G; Schädel, M; Yakushev, A; Åberg, S; Ackermann, D; Block, M; Brand, H; Carlsson, B G; Cox, D; Derkx, X; Dobaczewski, J; Eberhardt, K; Even, J; Fahlander, C; Gerl, J; Jäger, E; Kindler, B; Krier, J; Kojouharov, I; Kurz, N; Lommel, B; Mistry, A; Mokry, C; Nazarewicz, W; Nitsche, H; Omtvedt, J P; Papadakis, P; Ragnarsson, I; Runke, J; Schaffner, H; Schausten, B; Shi, Y; Thörle-Pospiech, P; Torres, T; Traut, T; Trautmann, N; Türler, A; Ward, A; Ward, D E; Wiehl, N

    2015-01-01

    Products of the fusion-evaporation reaction Ca-48 + Am-243 were studied with the TASISpec set-up at the gas-filled separator TASCA at the GSI Helmholtzzentrum f\\"ur Schwerionenforschung. Amongst the detected thirty correlated alpha-decay chains associated with the production of element Z=115, two recoil-alpha-fission and five recoil-alpha-alpha-fission events were observed. The latter are similar to four such events reported from experiments performed at the Dubna gas-filled separator. Contrary to their interpretation, we propose an alternative view, namely to assign eight of these eleven decay chains of recoil-alpha(-alpha)-fission type to start from the 3n-evaporation channel 115-288. The other three decay chains remain viable candidates for the 2n-evaporation channel 115-289.

  6. Exerpts from the history of alpha recoils.

    PubMed

    Samuelsson, Christer

    2011-05-01

    Any confined air volume holding radon ((222)Rn) gas bears a memory of past radon concentrations due to (210)Pb (T(1/2) = 22 y) and its progenies entrapped in all solid objects in the volume. The efforts of quantifying past radon exposures by means of the left-behind long-lived radon progenies started in 1987 with this author's unsuccessful trials of removing (214)Po from radon exposed glass objects. In this contribution the history and different techniques of assessing radon exposure to man in retrospect will be overviewed. The main focus will be on the implantation of alpha recoils into glass surfaces, but also potential traps in radon dwellings will be discussed. It is concluded that for a successful retrospective application, three crucial imperatives must be met, i.e. firstly, the object must persistently store a certain fraction of the created (210)Pb atoms, secondly, be resistant over decades towards disturbances from the outside and thirdly, all (210)Pb atoms analysed must originate from airborne radon only. For large-scale radon epidemiological studies, non-destructive and inexpensive measurement techniques are essential. Large-scale studies cannot be based on objects rarely found in dwellings or not available for measurements. PMID:21306801

  7. Imaging alpha particle detector

    DOEpatents

    Anderson, D.F.

    1980-10-29

    A method and apparatus for detecting and imaging alpha particles sources is described. A dielectric coated high voltage electrode and a tungsten wire grid constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source to be quantitatively or qualitatively analyzed. A thin polyester film window allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

  8. A Critical Review of Alpha Radionuclide Therapy—How to Deal with Recoiling Daughters?

    PubMed Central

    de Kruijff, Robin M.; Wolterbeek, Hubert T.; Denkova, Antonia G.

    2015-01-01

    This review presents an overview of the successes and challenges currently faced in alpha radionuclide therapy. Alpha particles have an advantage in killing tumour cells as compared to beta or gamma radiation due to their short penetration depth and high linear energy transfer (LET). Touching briefly on the clinical successes of radionuclides emitting only one alpha particle, the main focus of this article lies on those alpha-emitting radionuclides with multiple alpha-emitting daughters in their decay chain. While having the advantage of longer half-lives, the recoiled daughters of radionuclides like 224Ra (radium), 223Ra, and 225Ac (actinium) can do significant damage to healthy tissue when not retained at the tumour site. Three different approaches to deal with this problem are discussed: encapsulation in a nano-carrier, fast uptake of the alpha emitting radionuclides in tumour cells, and local administration. Each approach has been shown to have its advantages and disadvantages, but when larger activities need to be used clinically, nano-carriers appear to be the most promising solution for reducing toxic effects, provided there is no accumulation in healthy tissue. PMID:26066613

  9. A Critical Review of Alpha Radionuclide Therapy-How to Deal with Recoiling Daughters?

    PubMed

    de Kruijff, Robin M; Wolterbeek, Hubert T; Denkova, Antonia G

    2015-01-01

    This review presents an overview of the successes and challenges currently faced in alpha radionuclide therapy. Alpha particles have an advantage in killing tumour cells as compared to beta or gamma radiation due to their short penetration depth and high linear energy transfer (LET). Touching briefly on the clinical successes of radionuclides emitting only one alpha particle, the main focus of this article lies on those alpha-emitting radionuclides with multiple alpha-emitting daughters in their decay chain. While having the advantage of longer half-lives, the recoiled daughters of radionuclides like 224Ra (radium), 223Ra, and 225Ac (actinium) can do significant damage to healthy tissue when not retained at the tumour site. Three different approaches to deal with this problem are discussed: encapsulation in a nano-carrier, fast uptake of the alpha emitting radionuclides in tumour cells, and local administration. Each approach has been shown to have its advantages and disadvantages, but when larger activities need to be used clinically, nano-carriers appear to be the most promising solution for reducing toxic effects, provided there is no accumulation in healthy tissue. PMID:26066613

  10. Summary of Alpha Particle Transport

    SciTech Connect

    Medley, S.S.; White, R.B.; Zweben, S.J.

    1998-08-19

    This paper summarizes the talks on alpha particle transport which were presented at the 5th International Atomic Energy Agency's Technical Committee Meeting on "Alpha Particles in Fusion Research" held at the Joint European Torus, England in September 1997.

  11. Alpha-particle spectrometer experiment

    NASA Technical Reports Server (NTRS)

    Gorenstein, P.; Bjorkholm, P.

    1972-01-01

    Mapping the radon emanation of the moon was studied to find potential areas of high activity by detection of radon isotopes and their daughter products. It was felt that based on observation of regions overflown by Apollo spacecraft and within the field of view of the alpha-particle spectrometer, a radon map could be constructed, identifying and locating lunar areas of outgassing. The basic theory of radon migration from natural concentrations of uranium and thorium is discussed in terms of radon decay and the production of alpha particles. The preliminary analysis of the results indicates no significant alpha emission.

  12. Preferential leaching and natural annealing of alpha-recoil tracks in metamict betafite and samarskite

    SciTech Connect

    Lumpkin, G.R.; Ewing, R.C.; Eyal, Y.

    1988-03-01

    Leaching experiments on naturally occurring, metamict betafite and samarskite minerals in a bicarbonate--carbonate solution show strongly enhanced release to the solution of short-lived /sup 228/Th relative to its parent isotope /sup 232/Th (by a factor of 3 to 6), but only slightly enhanced dissolution (by a factor of 1.2 to 2) of long-lived /sup 234/U and /sup 230/Th relative to /sup 238/U and /sup 232/Th, respectively. The betafite (a complex Ca--U--Ti--Nb oxide of the pyrochlore group, A/sub 2-//sub m/B/sub 2/X/sub 6/Y/sub 0-1/xH/sub 2/O) and samarskite (a complex Y--Fe--U--Nb oxide with varying stoichiometry between ABO/sub 4/ and AB/sub 2/O/sub 6/) are x-ray and electron diffraction amorphous having experienced doses of 2.2--2.8 x 10/sup 17/ alpha-decay events/mg (24--31 dpa) and 3.8--4.4 x 10/sup 17/ alpha-decay events/mg (39--45 dpa), respectively. The isotopic fractionation is attributed to the radiation damage created by the alpha-decay events. Individual alpha-recoil tracks are preserved for some time as disordered regions of higher chemical reactivity in already fully damaged, aperiodic areas that result from the alpha-decay events. The annealing time of the alpha-recoil track within the aperiodic atomic array of the metamict state is calculated to be 29,300 +- 8100 years for samarskite and 42,700 +- 13,700 years for the betafite. These data plus data on an earlier studied betafite sample (annealing time = 2000 +- 1300 years) give an average annealing time of 25,000 +- 21,000 years.

  13. Electrochemical etching amplification of low-let recoil particle tracks in polymers for fast neutron dosimetry

    Microsoft Academic Search

    M. Sohrabi; K. Z. Morgan

    1975-01-01

    An electrochemical etching method for the amplification of fast-neutron-induced recoil particle tracks in polymers was investigated. The technique gave superior results over those obtained by conventional etching methods especially when polycarbonate foils were used for recoil particle track amplification. Electrochemical etching systems capable of multi-foil processing were designed and constructed to demonstrate the feasibility of the techniques for large-scale neutron

  14. cap alpha. Particle confinement in compact tori

    Microsoft Academic Search

    Bozhokin

    1986-01-01

    The motion of high-energy ..cap alpha.. particles in compact tori is studied. The classically accessible regions of motion of charged particles are found. The conditions are formulated under which the ..cap alpha.. particles produced in fusion reactions are absolutely confined. An ..cap alpha.. particle starting in a region enclosed by a ''critical'' surface will never, in the course of its

  15. Evaluation of ZnO(Ga)Coatings as Alpha Particle Transducers Within a Neutron Generator

    Microsoft Academic Search

    J. T. Mihalczo; J. S. Neal; J. C. Cooper; D. S. Koltick

    2002-01-01

    We report investigations and preliminary results from efforts to develop a recoil alpha particle detector for use in a portable neutron generator. The associated particle sealed tube neutron generator (APSTNG) will be used as an interrogation source for the Nuclear Materials Identification System (NMIS). With the emission of 14.1 MeV neutrons produced by the D-T reaction, associated 3.5 MeV alpha

  16. Experimental investigation of fission fragment and alpha-recoil induced ejection of secondary ions

    NASA Astrophysics Data System (ADS)

    Wien, K.; Becker, O.; Daab, P.; Nederveld, D.

    1980-03-01

    Secondary ions released from solid surfaces by fision fragments of 252Cf or by ?-recoil particles were studied with an improved time-of-flight mass spectrometer providing a mass resolution of ca. 2500. Firstly, we investigated the emission of secondary ions from insulators covered by a very thin metallic layer. At bombarding energies of ca. 100 MeV ion explosion spikes were expected to set in at a metallic surface coverage below 100 Å thickness. However, no substantial differences of yields were observed for 10-1000 Å Cr-films evaporated on Mylar. Secondly mass spectra and energy distributions of ions ejected by ca. 80 keV and ca. 100 MeV particles were studied. In both cases radioactive sources provided the bombarding particles. We used ?-recoil nuclei from 241Am and fission fragments from 252Cf. The comparison of the mass spectra shows clearly, that the energy transfer to secondary ions is considerably higher at 80 keV bombarding energy.

  17. cap alpha. -Particle confinement in compact tori

    SciTech Connect

    Bozhokin, S.V.

    1986-11-01

    The motion of high-energy ..cap alpha.. particles in compact tori is studied. The classically accessible regions of motion of charged particles are found. The conditions are formulated under which the ..cap alpha.. particles produced in fusion reactions are absolutely confined. An ..cap alpha.. particle starting in a region enclosed by a ''critical'' surface will never, in the course of its motion, intersect the separatrix of a compact torus. These critical surfaces are constructed. The ratio of the volume of absolute ..cap alpha.. confinement to the total volume of a compact torus is calculated as a function of the magnetic field strength and the dimensions of the compact torus.

  18. Cosmogenic production rates and recoil loss effects in micrometeorites and interplanetary dust particles

    NASA Astrophysics Data System (ADS)

    Trappitsch, Reto; Leya, Ingo

    2013-02-01

    We present a purely physical model to determine cosmogenic production rates for noble gases and radionuclides in micrometeorites (MMs) and interplanetary dust particles (IDPs) by solar cosmic-rays (SCR) and galactic cosmic-rays (GCR) fully considering recoil loss effects. Our model is based on various nuclear model codes to calculate recoil cross sections, recoil ranges, and finally the percentages of the cosmogenic nuclides that are lost as a function of grain size, chemical composition of the grain, and the spectral distribution of the projectiles. The main advantage of our new model compared with earlier approaches is that we consider the entire SCR particle spectrum up to 240 MeV and not only single energy points. Recoil losses for GCR-produced nuclides are assumed to be equal to recoil losses for SCR-produced nuclides. Combining the model predictions with Poynting-Robertson orbital lifetimes, we calculate cosmic-ray exposure ages for recently studied MMs, cosmic spherules, and IDPs. The ages for MMs and the cosmic-spherule are in the range <2.2-233 Ma, which corresponds, according to the Poynting-Robertson drag, to orbital distances in the range 4.0-34 AU. For two IDPs, we determine exposure ages of longer than 900 Ma, which corresponds to orbital distances larger than 150 AU. The orbital distance in the range 4-6 AU for one MM and the cosmic spherule indicate an origin either in the asteroid belt or release from comets coming either from the Kuiper Belt or the Oort Cloud. Three of the studied MMs have orbital distances in the range 23-34 AU, clearly indicating a cometary origin, either from short-period comets from the Kuiper Belt or from the Oort Cloud. The two IDPs have orbital distances of more than 150 AU, indicating an origin from Oort Cloud comets.

  19. Radioimmunotherapy with alpha-particle emitting radionuclides.

    PubMed

    Zalutsky, M R; Pozzi, O R

    2004-12-01

    An important consideration in the development of effective strategies for radioimmunotherapy is the nature of the radiation emitted by the radionuclide. Radionuclides decaying by the emission of alpha-particles offer the possibility of matching the cell specific reactivity of monoclonal antibodies with radiation with a range of only a few cell diameters. Furthermore, alpha-particles have important biological advantages compared with external beam radiation and beta-particles including a higher biological effectiveness, which is nearly independent of oxygen concentration, dose rate and cell cycle position. In this review, the clinical settings most likely to benefit from alpha-particle radioimmunotherapy will be discussed. The current status of preclinical and clinical research with antibodies labeled with 3 promising alpha-particle emitting radionuclides - (213)Bi, (225)Ac, and (211)At - also will be summarized. PMID:15640792

  20. Calculations of Alpha-Particle Trajectories for Long-Range Alpha Particles Emitted in Spontaneous Fission

    Microsoft Academic Search

    Y. Boneh; Z. Fraenkel; I. Nebenzahl

    1967-01-01

    Calculated angular and energy distributions of the alpha particles in long-range alpha-particle fission are presented. The distributions were obtained from calculated alpha-particle trajectories based on a three-point-charge model for the scissioning nucleus. The calculation is two dimensional, and spontaneous fission (no preferred direction) is assumed. This reduces the number of free variables of the system to seven (except for the

  1. The status of alpha-particle diagnostics

    SciTech Connect

    Young, K.M.; Johnson, D.W.

    1992-08-01

    There is a flurry of activity to complete alpha-particle diagnostics so that they can undergo some experimental testing in DT plasmas on JET or TFTR prior to implementation on ITER. Successful measurements of escaping charged fusion products have been made in DD plasmas, and the {alpha}-particle source can be well characterized by neutron profile measurement. These methods can be extrapolated to DT plasmas. Measurement of the confined {alpha}-particles requires a new technique. Collective Thomson scattering, methods involving charge-exchange interactions and nuclear reactions with impurities will be discussed. Some assessment is given of the capabilities of these techniques, bearing in mind the potential for their use in the physics phase of the ITER program.

  2. The status of alpha-particle diagnostics

    SciTech Connect

    Young, K.M.; Johnson, D.W.

    1992-01-01

    There is a flurry of activity to complete alpha-particle diagnostics so that they can undergo some experimental testing in DT plasmas on JET or TFTR prior to implementation on ITER. Successful measurements of escaping charged fusion products have been made in DD plasmas, and the {alpha}-particle source can be well characterized by neutron profile measurement. These methods can be extrapolated to DT plasmas. Measurement of the confined {alpha}-particles requires a new technique. Collective Thomson scattering, methods involving charge-exchange interactions and nuclear reactions with impurities will be discussed. Some assessment is given of the capabilities of these techniques, bearing in mind the potential for their use in the physics phase of the ITER program.

  3. Alternating current long range alpha particle detector

    DOEpatents

    MacArthur, D.W.; McAtee, J.L.

    1993-02-16

    An alpha particle detector, utilizing alternating currents, which is capable of detecting alpha particles from distinct sources. The use of alternating currents allows use of simpler ac circuits which, in turn, are not susceptible to dc error components. It also allows the benefit of gas gain, if desired. In the invention, a voltage source creates an electric field between two conductive grids, and between the grids and a conductive enclosure. Air containing air ions created by collision with alpha particles is drawn into the enclosure and detected. In some embodiments, the air flow into the enclosure is interrupted, creating an alternating flow of ions. In another embodiment, a modulated voltage is applied to the grid, also modulating the detection of ions.

  4. Alternating current long range alpha particle detector

    DOEpatents

    MacArthur, Duncan W. (Los Alamos, NM); McAtee, James L. (Los Alamos, NM)

    1993-01-01

    An alpha particle detector, utilizing alternating currents, whcih is capable of detecting alpha particles from distinct sources. The use of alternating currents allows use of simpler ac circuits which, in turn, are not susceptible to dc error components. It also allows the benefit of gas gain, if desired. In the invention, a voltage source creates an electric field between two conductive grids, and between the grids and a conductive enclosure. Air containing air ions created by collision with alpha particles is drawn into the enclosure and detected. In some embodiments, the air flow into the enclosure is interrupted, creating an alternating flow of ions. In another embodiment, a modulated voltage is applied to the grid, also modulating the detection of ions.

  5. The HERMES Recoil Detector Recoil Detector Test Beams

    E-print Network

    detector versus the of the incoming particle and the position of incidence on the strip. The data was takenThe HERMES Recoil Detector Recoil Detector Test Beams A will be installed to the HERMES experiment of fromprotons recoil detector Deeply Virtual Compton Scattering (DVCS). Recoil proton momentum versus polar

  6. Nuclear diagnostic for fast alpha particles

    DOEpatents

    Grisham, Larry R. (Lawrence Township, Mercer County, NJ); Post, Jr., Douglass E. (Belle Mead, NJ); Dawson, John M. (Pacific Palisades, CA)

    1986-01-01

    Measurement of the velocity distribution of confined energetic alpha particles resulting from deuterium-tritium fusion reactions in a magnetically contained plasma is provided. The fusion plasma is seeded with energetic boron neutrals for producing, by means of the reaction .sup.10 B (.alpha.,n) .sup.13 N reaction, radioactive nitrogen nuclei which are then collected by a probe. The radioactivity of the probe is then measured by conventional techniques in determining the energy distribution of the alpha particles in the plasma. In a preferred embodiment, diborane gas (B.sub.2 H.sub.6) is the source of the boron neutrals to produce .sup.13 N which decays almost exclusively by positron emission with a convenient half-life of 10 minutes.

  7. Alpha particle analysis using PEARLS spectrometry

    SciTech Connect

    McKlveen, J.W.; Klingler, G.W.; McDowell, W.J.; Case, G.N.

    1984-01-01

    Alpha particle assay by conventional plate-counting methods is difficult because chemical separation, tracer techniques, and/or self-absorption losses in the final sample may cause either non-reproducible results or create unacceptable errors. PEARLS (Photon-Electron Rejecting Alpha Liquid Scintillation) Spectrometry is an attractive alternative since radionuclides may be extracted into a scintillator in which there would be no self-absorption or geometry problems and in which up to 100% chemical recovery and counting efficiency is possible. Sample preparation may include extraction of the alpha emitter of interest by a specific organic-phase-soluble compound directly into the liquid scintillator. Detection electronics use energy and pulse-shape discrimination to provide discrete alpha spectra and virtual absence of beta and gamma backgrounds. Backgrounds on the order of 0.01 cpm are readily achievable. Accuracy and reproducibility are typically in the 100 +-1% range. Specific procedures have been developed for gross alpha, uranium, plutonium, thorium, and polonium assay. This paper will review liquid scintillation alpha counting methods and reference some of the specific applications. 8 refs., 1 fig.

  8. Patient-specific alpha-particle dosimetry.

    PubMed

    Palm, Stig; Elgqvist, Jörgen; Jacobsson, Lars

    2011-10-01

    Alpha-particle therapy has received increased attention during the last few years because of the development of new targeting constructs and new labeling techniques and the availability of suitable ?-particle - emitting radionuclides. This work provides an overview of methods that have been used in clinical trials in estimating the absorbed dose to tumors and healthy tissue in patients following such ?-particle therapy. Similarities and differences compared to conventional therapies using ?¯-particle emitters are presented. The specific challenges of establishing accurate dosimetry for ?- particles in the individual patient are also discussed, as is the effect that improved patient-specific dosimetry might have on the overall efficacy of this type of therapy. PMID:22202155

  9. Alpha-particle-induced soft errors in dynamic memories

    Microsoft Academic Search

    T. C. May; M. H. Woods

    1979-01-01

    A new physical soft error mechanism in dynamic RAM's and CCD's is the upset of stored data by the passage of alpha particles through the memory array area. The alpha particles are emitted by the radioactive decay of uranium and thorium which are present in parts-per-million levels in packaging materials. When an alpha particle penetrates the die surface, it can

  10. ALPHA-PARTICLE RADIOBIOLOGICAL EXPERIMENTS USING THIN CR-39 DETECTORS

    E-print Network

    Yu, K.N.

    ALPHA-PARTICLE RADIOBIOLOGICAL EXPERIMENTS USING THIN CR-39 DETECTORS K. F. Chan1 , S. Y. M. Siu2 advantages of using CR-39 detectors as the cell-culture substrates in alpha-particle radiobiological the DNA damage in individual HeLa cervix cancer cells after alpha-particle irradiation. We prepared thin

  11. Gallium Nitride Room Temperature alpha Particle Detectors

    Microsoft Academic Search

    Min Lu; Guo-Guang Zhang; Kai Fu; Guo-Hao Yu

    2010-01-01

    Gallium Nitride (GaN) room temperature alpha particle detectors are fabricated and characterized, whose device structure is Schottky diode. The current-voltage (I - V) measurements reveal that the reverse breakdown voltage of the detectors is more than 200 V owing to the consummate fabrication processes, and that the Schottky barrier and ideal factor of the detectors are 0.64 eV and 1.02,

  12. Alpha-recoil tracks in natural dark mica: Dating geological samples by optical and scanning force microscopy

    NASA Astrophysics Data System (ADS)

    Glasmacher, U. A.; Lang, M.; Klemme, S.; Moine, B.; Barbero, L.; Neumann, R.; Wagner, G. A.

    2003-08-01

    Alpha-recoil tracks (ART) are lattice defects caused by the ?-decay of 238U, 235U, 232Th, and daughter products. Visualization of etched ARTs in dark mica by phase-contrast microscopy allows dating of Quaternary geological as well as archaeological materials. Visualization of etched ARTs by Nomarski-differential-interference-contrast microscopy (NDICM) and scanning force microscopy (SFM) enables the access to areal densities ( ?a) of ART etch pits beyond 10 4 mm -2 and thus the extension of the new ART-dating technique to an age range >1 Ma. The successful application of SFM as a new tool in geochronology could open the way to a field to be characterized as nanogeochronology. In order to visualize ARTs by NDICM and SFM, dark mica was etched with 4% HF at 21 °C for 5-107 min. A linear relationship between ?a and etching time ( te) was observed for phlogopites from the Kerguelen Islands (French territory, Indian Ocean), and the Kovdor magmatic complex (Russia). The volume density ( ?v) of ART is a function of etching speed ( veff) and slope of the ?a-growth curve. The ART-age equation allows the calculation of an individual ?v-growth curve for the phlogopite analysed by us using the uranium and thorium content. The ART-ages were determined by combining the experimentally obtained volume density with the individual ?v-growth curve.

  13. Scintillation of Liquid Helium for Low-Energy Nuclear Recoils

    E-print Network

    Ito, T M

    2013-01-01

    The scintillation properties of liquid helium upon the recoil of a low energy helium atom are discussed in the context of the possible use of this medium as a detector of dark matter. It is found that the prompt scintillation yield in the range of recoil energies from a few keV to 100 keV is somewhat higher than that obtained by a linear extrapolation from the measured yield for an 5 MeV alpha particle. A comparison is made of both the scintillation yield and the charge separation by an electric field for nuclear recoils and for electrons stopped in helium.

  14. Recoil Distance Method lifetime measurements via gamma-ray and charged-particle spectroscopy at NSCL

    NASA Astrophysics Data System (ADS)

    Voss, Philip Jonathan

    The Recoil Distance Method (RDM) is a well-established technique for measuring lifetimes of electromagnetic transitions. Transition matrix elements derived from the lifetimes provide valuable insight into nuclear structure. Recent RDM investigations at NSCL present a powerful new model-independent tool for the spectroscopy of nuclei with extreme proton-to-neutron ratios that exhibit surprising behavior. Neutron-rich 18C is one such example, where a small B(E2; 2+1 ? 0+gs) represented a dramatic shift from the expected inverse relationship between the B(E2) and 2+1 excitation energy. To shed light on the nature of this quadrupole excitation, the RDM lifetime technique was applied with the Koln/NSCL plunger. States in 18C were populated by the one-proton knockout reaction of a 19N secondary beam. De-excitation gamma rays were detected with the Segmented Germanium Array in coincidence with reaction residues at the focal plane of the S800 Magnetic Spectrometer. The deduced B(E2) and excitation energy were both well described by ab initio no-core shell model calculations. In addition, a novel extension of RDM lifetime measurements via charged-particle spectroscopy of exotic proton emitters has been investigated. Substituting the reaction residue degrader of the Koln/NSCL plunger with a thin silicon detector permits the study of short-lived nuclei beyond the proton dripline. A proof of concept measurement of the mean lifetime of the two-proton emitter 19Mg was conducted. The results indicated a sub-picosecond lifetime, one order of magnitude smaller than the published results, and validate this new technique for lifetime measurements of charged-particle emitters.

  15. Targeted alpha particle immunotherapy for myeloid leukemia.

    PubMed

    Jurcic, Joseph G; Larson, Steven M; Sgouros, George; McDevitt, Michael R; Finn, Ronald D; Divgi, Chaitanya R; Ballangrud, Ase M; Hamacher, Klaus A; Ma, Dangshe; Humm, John L; Brechbiel, Martin W; Molinet, Roger; Scheinberg, David A

    2002-08-15

    Unlike beta particle-emitting isotopes, alpha emitters can selectively kill individual cancer cells with a single atomic decay. HuM195, a humanized anti-CD33 monoclonal antibody, specifically targets myeloid leukemia cells and has activity against minimal disease. When labeled with the beta-emitters (131)I and (90)Y, HuM195 can eliminate large leukemic burdens in patients, but it produces prolonged myelosuppression requiring hematopoietic stem cell transplantation at high doses. To enhance the potency of native HuM195 yet avoid the nonspecific cytotoxicity of beta-emitting constructs, the alpha-emitting isotope (213)Bi was conjugated to HuM195. Eighteen patients with relapsed and refractory acute myelogenous leukemia or chronic myelomonocytic leukemia were treated with 10.36 to 37.0 MBq/kg (213)Bi-HuM195. No significant extramedullary toxicity was seen. All 17 evaluable patients developed myelosuppression, with a median time to recovery of 22 days. Nearly all the (213)Bi-HuM195 rapidly localized to and was retained in areas of leukemic involvement, including the bone marrow, liver, and spleen. Absorbed dose ratios between these sites and the whole body were 1000-fold greater than those seen with beta-emitting constructs in this antigen system and patient population. Fourteen (93%) of 15 evaluable patients had reductions in circulating blasts, and 14 (78%) of 18 patients had reductions in the percentage of bone marrow blasts. This study demonstrates the safety, feasibility, and antileukemic effects of (213)Bi-HuM195, and it is the first proof-of-concept for systemic targeted alpha particle immunotherapy in humans. PMID:12149203

  16. Measurement of Alpha Particle Radioactivtiy in IC Device Packages

    Microsoft Academic Search

    E. S. Meieran; P. R. Engel; T. C. May

    1979-01-01

    Alpha particle radioactivity in package materials has been shown to cause soft errors in semiconductor devices. The particles are emitted by uranium and thorium decay sequence radioactive isotopes present as trace impurities in the raw materials used to make the package component parts. Chemical and radiation analys s techniques were correlated to alpha particle fluxes, which range in value from

  17. Alpha particle effects on the internal kink and fishbone modes

    SciTech Connect

    Wu, Y.; Cheng, C.Z.; White, R.B. (Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08540 (United States))

    1994-10-01

    The effects of alpha particles on the internal kink and fishbone modes are studied analytically. The nonadiabatic contribution from untrapped alpha particles is negligible. Finite inverse aspect ratio, plasma [beta], and plasma shaping effects can significantly enhance the trapped particle drift reversal domain in the pitch angle space and reduce the bounce-averaged magnetic drift frequency. The decrease of the drift magnitude and drift reversal effects on the ideal kink mode is small, but the [beta][sub [alpha

  18. Alpha particle loss in the TFTR DT experiments

    SciTech Connect

    Zweben, S.J.; Darrow, D.S.; Herrmann, H.W. [and others

    1995-01-01

    Alpha particle loss was measured during the TFTR DT experiments using a scintillator detector located at the vessel bottom in the ion grad-B drift direction. The DT alpha particle loss to this detector was consistent with the calculated first-orbit loss over the whole range of plasma current I=0.6-2.7 MA. In particular, the alpha particle loss rate per DT neutron did not increase significantly with fusion power up to 10.7 MW, indicating the absence of any new ``collective`` alpha particle loss processes in these experiments.

  19. Epithermal and thermal alpha-particle transport and control

    SciTech Connect

    Miley, G.H.; Hu, S.C.; Varadarajan, V. (Illinois Univ., Urbana, IL (United States))

    1990-12-01

    In this paper alpha-particle ash accumulation in tokamaks and two possible ash control techniques are discussed. The effect of thermal alpha-particle ash accumulation on plasma performance is examined using a zero-dimensional analysis with profile corrections. Alpha-particle accumulation is shown to have serious effects on ignition requirements. An analytical model developed to predict the effect of sawtooth disruption on ash accumulation is discussed. The analytical results indicate that the sawtooth is effective when the temperature profile is parabolic or flatter. Alpha-particle ejection by a fishbone oscillation is envisaged to be helpful in ash control, and a model of the physics in a large-aspect-ratio approximation is discussed using an extended version of a Chen et al. formalism. The trapped particle destabilization of the internal kinks due to the alpha particles and a second hot-particle species is considered, and the expected oscillation frequency and growth rates are derived.

  20. Analytic expressions for {alpha} particle preformation in heavy nuclei

    SciTech Connect

    Zhang, H. F.; Wang, Y. J.; Dong, J. M. [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Royer, G. [Laboratoire Subatech, UMR IN2P3/CNRS Universite Ecole des Mines, Nantes 44 (France); Zuo, W.; Li, J. Q. [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2009-11-15

    Experimental {alpha} decay energies and half-lives are investigated systematically to extract {alpha} particle preformation in heavy nuclei. Formulas for the preformation factors are proposed that can be used to guide microscopic studies on preformation factors and perform accurate calculations of the {alpha} decay half-lives. There is little evidence for the existence of an island of long stability of superheavy nuclei.

  1. Dosimetry and radiobiological studies of automated alpha-particle irradiator.

    PubMed

    M V, Jyothish Babu; Shinde, Sanjay G; S, Sunil Kumar; Ali, Manjoor; Vasumathy, R; Kumar, Amit; Kolekar, R; Kumar, Manish; Nema, P; Bhagwat, P V; Pandey, Badri N

    2013-01-01

    Understanding the effect of alpha radiation on biological systems is an important component of radiation risk assessment and associated health consequences. However, due to the short path length of alpha radiation in the atmosphere, in vitro radiobiological experiments cannot be performed with accuracy in terms of dose and specified exposure time. The present paper describes the design and dosimetry of an automated alpha-particle irradiator named 'BARC BioAlpha', which is suitable for in vitro radiobiological studies. Compared to alpha irradiators developed in other laboratories, BARC BioAlpha has integrated computer-controlled movement of the alpha-particle source, collimator, and electronic shutter. The diaphragm blades of the electronic shutter can control the area (diameter) of irradiation without any additional shielding, which is suitable for radiobiological bystander studies. To avoid irradiation with incorrect parameters, a software interlock is provided to prevent shutter opening, unless the user-specified speed of the source and collimator are achieved. The dosimetry of the alpha irradiator using CR-39 and silicon surface barrier detectors showed that ~4 MeV energy of the alpha particle reached the cells on the irradiation dish. The alpha irradiation was also demonstrated by the evaluation of DNA double-strand breaks in human cells. In conclusion, 'BARC BioAlpha' provides a user-friendly alpha irradiation system for radiobiological experiments with a novel automation mechanism for better accuracy of dose and exposure time. PMID:24266413

  2. Molecular modeling of the effects of 40Ar recoil in illite particles on their K-Ar isotope dating

    NASA Astrophysics Data System (ADS)

    Szczerba, Marek; Derkowski, Arkadiusz; Kalinichev, Andrey G.; ?rodo?, Jan

    2015-06-01

    The radioactive decay of 40K to 40Ar is the basis of isotope age determination of micaceous clay minerals formed during diagenesis. The difference in K-Ar ages between fine and coarse grained illite particles has been interpreted using detrital-authigenic components system, its crystallization history or post-crystallization diffusion. Yet another mechanism should also be considered: natural 40Ar recoil. Whether this recoil mechanism can result in a significant enough loss of 40Ar to provide observable decrease of K-Ar age of the finest illite crystallites at diagenetic temperatures - is the primary objective of this study which is based on molecular dynamics (MD) computer simulations. All the simulations were performed for the same kinetic energy (initial velocity) of the 40Ar atom, but for varying recoil angles that cover the entire range of their possible values. The results show that 40Ar recoil can lead to various deformations of the illite structure, often accompanied by the displacement of OH groups or breaking of the Si-O bonds. Depending on the recoil angle, there are four possible final positions of the 40Ar atom with respect to the 2:1 layer at the end of the simulation: it can remain in the interlayer space or end up in the closest tetrahedral, octahedral or the opposite tetrahedral sheet. No simulation angles were found for which the 40Ar atom after recoil passes completely through the 2:1 layer. The energy barrier for 40Ar passing through the hexagonal cavity from the tetrahedral sheet into the interlayer was calculated to be 17 kcal/mol. This reaction is strongly exothermic, therefore there is almost no possibility for 40Ar to remain in the tetrahedral sheet of the 2:1 layer over geological time periods. It will either leave the crystal, if close enough to the edge, or return to the interlayer space. On the other hand, if 40Ar ends up in the octahedral sheet after recoil, a substantially higher energy barrier of 55 kcal/mol prevents it from leaving the TOT layer over geological time. Based on the results of MD simulations, the estimates of the potential effect of 40Ar recoil on the K-Ar dating of illite show that some of 40Ar is lost and the loss is substantially dependent on the crystallite dimensions. The 40Ar loss can vary from 10% for the finest crystallites (two 2:1 layers thickness and <0.02 ?m in diameter) to close to zero for the thickest and largest (in the ab plane) ones. Because the decrease of the K-Ar estimated age is approximately proportional to the 40Ar loss, the finer crystallites show lower apparent age than the coarser ones, although the age of crystallization is assumed equal for all the crystallites. From the model it is also clear that the lack of K removal from illite fringes (potentially Ar-free) strongly increases the apparent age differences among crystallites of different size.

  3. ITER alpha particle diagnostics using knock-on ion tails

    SciTech Connect

    Fisher, R.K.; Parks, P.B.; McChesney, J.M. [and others

    1995-09-01

    Alpha particles will play a critical role in the physics and successful operation of ITER. Achieving fusion ignition requires that the {alpha} particles created by deuterium-tritium (D-T) reactions deposit a large fraction of their energy in the reacting plasma before they are lost. Toroidal field ripple can localize any alpha particle losses and cause first wall damage. We have proposed a new method of measuring the fast confined {alpha}-particle distribution in a reacting plasma. The same elastic collisions that transfer the alpha energy to the D-T plasma ions and allow fusion ignition will also create a high energy tail on the deuterium and tritium ion energy distributions. Some of these energetic tail ions will undergo fusion reactions with the background plasma producing neutrons whose energy is increased significantly above 14 MeV due to the kinetic energy of the reacting ions. Measurement of this high energy tail on the D-T neutron distribution as a function of plasma minor radius would provide information on the alpha density profile with a time response equal to the ion slowing-down time. Although this technique may provide only limited information on the {alpha}-particle energy distribution, experimental studies of fast ions on existing tokamaks have shown that the observed slowing-down is essentially classical. Hence the {alpha}-energy distribution is expected to be classical except in situations where the {alpha}-confinement is poor. The confinement of {alpha}`s can be affected by ripple losses and a number of instabilities. Toroidal field ripple can cause both prompt orbit losses and stochastic ripple diffusion losses. Magnetohydrodynamic activity, including fishbone instabilities, toroidal Alfven eigenmodes, and sawtooth oscillations, may also affect alpha confinement. The diagnostic proposed here, by monitoring the confined alpha population, can provide valuable information on the confinement of fast alphas in a reacting plasma.

  4. {alpha}-particle spectrum in the reaction p + {sup 11}B {yields} {alpha} + {sup 8}Be* {yields} 3{alpha}

    SciTech Connect

    Dmitriev, V. F., E-mail: dmitriev@inp.nsk.s [Budker Institute of Nuclear Physics (Russian Federation)

    2009-07-15

    Using a simple phenomenological parametrization of the reaction amplitude we calculated {alpha}-particle spectrumin the reaction p + {sup 11}B {yields} {alpha} + {sup 8}Be* {yields} 3{alpha} at the resonance proton energy of 675 keV. The parametrization includes Breit-Wigner factor with an energy-dependent width for intermediate {sup 8}Be* state and the Coulomb and the centrifugal factors in {alpha}-particle-emission vertices. The shape of the spectrum consists of a well-defined peak corresponding to emission of the primary {alpha} and a flat shoulder going down to very low energy. We found that below 1.5MeV there are 17.5% of {alpha}'s and below 1MeV there are 11% of them.

  5. Alpha particle effects on the internal kink and fishbone modes

    SciTech Connect

    Wu, Y.; Cheng, C.Z.; White, R.B.

    1994-06-01

    The effects of alpha particles on the internal kink and fishbone modes are studied analytically. The nonadiabatic contribution from untrapped alpha particles is negligible. Finite inverse aspect ratio, plasma {beta} and plasma shaping effects can significantly enhance the trapped particle drift reversal domain in the pitch angle space and reduce the bounce-averaged magnetic drift frequency. The drift reversal effect on the ideal kink mode is small, but the {beta}{sub {alpha}} threshold for the fishbone mode can be much lower than previously predicted. Moreover, the fishbone mode could be excited by alpha particles even when the plasma is stable in the ideal MHD limit. In addition, the ion diamagnetic drift frequency (finite ion Larmor radius effect) has a strong destabilizing effect on the fishbone mode when it is comparable with the trapped alpha averaged precessional drift frequency, even though it stabilizes the plasma in the ideal MHD limit.

  6. Effect of alpha particles on Toroidal Alfven Eigenmodes

    SciTech Connect

    Berk, H.L.

    1992-11-01

    An overview is given of the analytic structure for the linear theory of the Toroidal Alfven Eigenmode (TAE), where multiple gap structures occur. A discussion is given of the alpha particle drive and the various dissipation mechanisms that can stabilize the system. A self-consistent calculation of the TAE mode, for a low-beta high-aspect-ratio plasma, indicates that though the alpha particle drive is comparable to the dissipation mechanisms, overall stability is still achieved for ignited ITER-like plasma. A brief discussion is given of the nonlinear theory for the TAE mode and how nonlinear alpha particle dynamics can be treated by mapping methods.

  7. Alpha particle losses from Tokamak Fusion Test Reactor deuteriumtritium plasmas*

    E-print Network

    Alpha particle losses from Tokamak Fusion Test Reactor deuterium­tritium plasmas* D. S. Darrow, S. Petrov,e) C. K. Phillips, M. H. Redi, E. Ruskov,d) D. A. Spong,b) E. J. Strait,c) G. Taylor, R. B. White have a significant influence on tokamak reactor viability, the loss of deuterium­tritium alpha

  8. Measurement of alpha particle energy using windowless electret ion chambers.

    PubMed

    Dua, S K; Kotrappa, P; Srivastava, R; Ebadian, M A; Stieff, L R

    2002-10-01

    Electret ion chambers are inexpensive, lightweight, robust, commercially available, passive, charge-integrating devices for accurate measurement of different ionizing radiations. In an earlier work a chamber of dimensions larger than the range of alpha particles having aluminized Mylar windows of different thickness was used for measurement of alpha radiation. Correlation between electret mid-point voltage, alpha particle energy, and response was developed and it was shown that this chamber could be used for estimating the effective energy of an unknown alpha source. In the present study, the electret ion chamber is used in the windowless mode so that the alpha particles dissipate their entire energy inside the volume, and the alpha particle energy is determined from the first principles. This requires that alpha disintegration rate be accurately known or measured by an alternate method. The measured energies were within 1 to 4% of the true values for different sources (230Th, 237Np, 239Pu, 241Am, and 224Cm). This method finds application in quantitative determination of alpha energy absorbed in thin membrane and, hence, the absorbed dose. PMID:12240732

  9. Full orbit calculation for lost alpha particle measurement on ITERa)

    NASA Astrophysics Data System (ADS)

    Funaki, D.; Isobe, M.; Nishiura, M.; Sato, Y.; Okamoto, A.; Kobuchi, T.; Kitajima, S.; Sasao, M.

    2008-10-01

    An orbit following calculation code with full gyromotion under the ITER magnetic field configuration has been developed to investigate escaping alpha particle orbits in ITER and to determine the geometrical arrangement for alpha particle detection. The code contained the full geometrical information of the first wall panels. It was carefully investigated whether an alpha particle escaping from the plasma through the last closed flux surface does not touch or intersect the first wall boundary before reaching the detection point. Candidates of blanket module modification have been studied to achieve effective measurement geometry for escaping alpha particle detection. The calculations showed that direct orbit loss and banana diffusion can be detected with a probe head recessed from the first wall surface.

  10. Evaluation of silicon active pixel sensors for alpha particle detection

    NASA Astrophysics Data System (ADS)

    Maneuski, Dzmitry; Blue, Andrew; Hynds, Daniel; Mac Raighne, Aaron; O'Shea, Val

    2011-12-01

    Alpha particles can be used as a test stimulus offering several advantages for probing materials of micrometre thicknesses. In this work a silicon CMOS Active Pixel Sensor (APS) is evaluated for alpha particle detection and imaging. These devices can replace traditionally used solid-state track detectors, giving advantages of increased sensitivity, improved linearity and higher dynamic range. CMOS APSs offer high detection efficiency, low noise and digital readout. Qualitative and quantitative analysis of the back-illuminated back-thinned (BT) and standard sensor response to 5.5 MeV alpha particles is presented. Alpha particle detection efficiency was estimated and energy resolution was measured. Imaging capabilities were assessed and quantified. Cluster centroiding algorithms were implemented for image quality improvement.

  11. Full orbit calculation for lost alpha particle measurement on ITER

    SciTech Connect

    Funaki, D.; Isobe, M.; Nishiura, M.; Sato, Y.; Okamoto, A.; Kobuchi, T.; Kitajima, S.; Sasao, M. [Department of Quantum Energy Science, Tohoku University, Sendai 980-8579 (Japan)

    2008-10-15

    An orbit following calculation code with full gyromotion under the ITER magnetic field configuration has been developed to investigate escaping alpha particle orbits in ITER and to determine the geometrical arrangement for alpha particle detection. The code contained the full geometrical information of the first wall panels. It was carefully investigated whether an alpha particle escaping from the plasma through the last closed flux surface does not touch or intersect the first wall boundary before reaching the detection point. Candidates of blanket module modification have been studied to achieve effective measurement geometry for escaping alpha particle detection. The calculations showed that direct orbit loss and banana diffusion can be detected with a probe head recessed from the first wall surface.

  12. Q Values in alpha-Particle-Accompanied Ternary Fission

    Microsoft Academic Search

    N. Feather

    1968-01-01

    In relation to any mode of binary fission, there are nine possible ways in which the constituents of an alpha particle can be assembled using nucleons from one or both of the nascent binary fragments. Basing a definition of \\

  13. Alpha particle radiography with the CR39 nuclear track detector

    Microsoft Academic Search

    B. A. de Souza; S. C. Cabral; R. T. Lopes

    1995-01-01

    This work studies the alpha particle radiography technique, in conjunction with the CR-39 plastic track detector. The irradiations were made in the CV-28 cyclotron at IEN\\/CNEN\\/RJ, using a 7 MeV\\/nucleon alpha particle beam. All etches were performed by using a 6.25 N NaOH solution, at 70°C. The best etch time to obtain radiographs was determined. A calibration curve (Gray Levels

  14. Alpha particle effects on the internal kink modes

    SciTech Connect

    Wu, Yanlin; Cheng, C.Z.

    1994-08-01

    The {alpha}-particle effects on the internal kink mode stability are studied. Finite Grad-Shafranov Shift, plasma {beta}, and plasma shape can significantly enhance the trapped particle drift reversal domain in pitch angle space and reduce average magnetic drift frequency. The drift reversal effect on the ideal kink mode is small, but the {beta}{sub {alpha}} threshold for the fishbone mode can be much lower than previously predicted. In addition, the ion diamagnetic drift has a stronger destabilizing effect.

  15. Shielding of manned space vehicles against protons and alpha particles

    NASA Technical Reports Server (NTRS)

    Alsmiller, R. G., Jr.; Santoro, R. T.; Barish, J.; Claiborne, H. C.

    1972-01-01

    The available information on the shielding of manned space vehicles against protons and alpha particles is summarized. The emphasis is placed on shielding against Van Allen belt protons and against solar-flare protons and alpha particles, but information on shielding against galactic cosmic rays is also presented. The approximation methods for use by nonexperts in the space shielding field are those that are standard in the space shielding literature.

  16. Actinium-225 in targeted alpha-particle therapeutic applications.

    PubMed

    Scheinberg, David A; McDevitt, Michael R

    2011-10-01

    Alpha particle-emitting isotopes are being investigated in radioimmunotherapeutic applications because of their unparalleled cytotoxicity when targeted to cancer and their relative lack of toxicity towards untargeted normal tissue. Actinium- 225 has been developed into potent targeting drug constructs and is in clinical use against acute myelogenous leukemia. The key properties of the alpha particles generated by 225Ac are the following: i) limited range in tissue of a few cell diameters; ii) high linear energy transfer leading to dense radiation damage along each alpha track; iii) a 10 day halflife; and iv) four net alpha particles emitted per decay. Targeting 225Ac-drug constructs have potential in the treatment of cancer. PMID:22202153

  17. Alpha particle backscattering measurements used for chemical analysis of surfaces

    NASA Technical Reports Server (NTRS)

    Patterson, J. H.

    1967-01-01

    Alpha particle backscattering performs a chemical analysis of surfaces. The apparatus uses a curium source and a semiconductor detector to determine the energy spectrum of the particles. This in turn determines the chemical composition of the surface after calibration to known samples.

  18. High acceptance recoil polarimeter

    SciTech Connect

    The HARP Collaboration

    1992-12-05

    In order to detect neutrons and protons in the 50 to 600 MeV energy range and measure their polarization, an efficient, low-noise, self-calibrating device is being designed. This detector, known as the High Acceptance Recoil Polarimeter (HARP), is based on the recoil principle of proton detection from np[r arrow]n[prime]p[prime] or pp[r arrow]p[prime]p[prime] scattering (detected particles are underlined) which intrinsically yields polarization information on the incoming particle. HARP will be commissioned to carry out experiments in 1994.

  19. Analysis of radiation risk from alpha particle component of soalr particle events

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; Townsend, L. W.; Wilson, J. W.; Golightly, M. J.; Weyland, M.

    1994-01-01

    The Solar Particle Events (SPE) will contain a primary alpha particle component, representing a possible increase in the potential risk to astronauts during an SPE over the often studied proton component. We discuss the physical interactions of alpha particles important in describing the transport of these particles through spacecraft and body shielding. Models of light ion reactions are presented and their effects on energy and Linear Energy Transfer (LET) spectra in shielding are discussed. We present predictions of particle spectra, dose, and dose equivalent in organs of interest for SPE spectra typical of those occurring in recent solar cycles. The large events of solar cycle 19 are found to have substantial increase in biological risk from alpha particles, including a large increase in secondary neutron production from alpha particle breakup.

  20. Utility of extracting {alpha}-particle energy by waves

    SciTech Connect

    Fisch, N.J.; Herrmann, M.C.

    1994-05-01

    The utility of extracting {alpha}-particle power, and then diverting this power to fast fuel ions, is investigated. As power is diverted to fast ions and then to ions, a number of effects come into play, as the relative amounts of pressure taken up by electrons, fuel ions, and fast {alpha}-particles shift. In addition, if the {alpha}-particle power is diverted to fast fuel ions, there is an enhanced fusion reactivity because of the nonthermal component of the ion distribution. Some useful expressions for describing these effects are derived, and it is shown that fusion reactors with power density about twice what otherwise might be obtained can be contemplated, so long as a substantial amount of the {alpha}-particle power can be diverted. Interestingly, in this mode of operation, once the electron heat is sufficiently confined, further improvement in confinement is actually not desirable. A similar improvement in fusion power density can be obtained for advanced fuel mixtures such as D-He{sup 3}, where the power of both the energetic {alpha}-particles and the energetic protons might be diverted advantageously.

  1. Alpha-Particle Condensation in Nuclear Systems

    NASA Astrophysics Data System (ADS)

    Schuck, P.; Funaki, Y.; Horiuchi, H.; Röpke, G.; Tohsaki, A.; Yamada, T.

    2013-02-01

    The onset of quartetting, i.e. ?-particle condensation, in symmetric and asymmetric nuclear matter is studied with the help of an in-medium modified four nucleon equation. It is found that at very low density quartetting wins over pairing, because of the strong binding of the ?-particles. The critical temperature can reach values up to around 8 MeV. The disappearance of ?-particles with increasing density, i.e. the Mott transition, is investigated. In finite nuclei the Hoyle state, that is the 02+ of 12C is identified as an '?-particle condensate' state. It is conjectured that such states also exist in heavier n?-nuclei, like 16O, 20Ne, etc. The sixth 0+ state in 16O is proposed as an analogue to the Hoyle state. The Gross-Pitaevski equation is employed to make an estimate of the maximum number of ? particles a condensate state can contain. Possible quartet condensation in other systems is discussed briefly.

  2. Targeted alpha-particle immunotherapy for acute myeloid leukemia.

    PubMed

    Jurcic, Joseph G; Rosenblat, Todd L

    2014-01-01

    Because alpha-particles have a shorter range and a higher linear energy transfer (LET) compared with beta-particles, targeted alpha-particle immunotherapy offers the potential for more efficient tumor cell killing while sparing surrounding normal cells. To date, clinical studies of alpha-particle immunotherapy for acute myeloid leukemia (AML) have focused on the myeloid cell surface antigen CD33 as a target using the humanized monoclonal antibody lintuzumab. An initial phase I study demonstrated the safety, feasibility, and antileukemic effects of bismuth-213 ((213)Bi)-labeled lintuzumab. In a subsequent study, (213)Bi-lintuzumab produced remissions in some patients with AML after partial cytoreduction with cytarabine, suggesting the utility of targeted alpha-particle therapy for small-volume disease. The widespread use of (213)Bi, however, is limited by its short half-life. Therefore, a second-generation construct containing actinium-225 ((225)Ac), a radiometal that generates four alpha-particle emissions, was developed. A phase I trial demonstrated that (225)Ac-lintuzumab is safe at doses of 3 ?Ci/kg or less and has antileukemic activity across all dose levels studied. Fractionated-dose (225)Ac-lintuzumab in combination with low-dose cytarabine (LDAC) is now under investigation for the management of older patients with untreated AML in a multicenter trial. Preclinical studies using (213)Bi- and astatine-211 ((211)At)-labeled anti-CD45 antibodies have shown that alpha-particle immunotherapy may be useful as part conditioning before hematopoietic cell transplantation. The use of novel pretargeting strategies may further improve target-to-normal organ dose ratios. PMID:24857092

  3. Nuclear alpha-particle condensates or the emperor's new clothes

    E-print Network

    Zinner, N T

    2007-01-01

    We assess the validity of recent claims for appearance of alpha-cluster condensation in nuclei. We compare different measures of condensation and show that few-body nuclear condensates are ill-defined. We use the quantality condition of Mottelson, separating solid and mean-field structures, to emphasize the conflict between localization and condensate formation. We explore the connection between Ikeda diagrams, linear chains and Tonks-Girardeau gasses. We show that no new information is contained in approximations of nuclear states as alpha-cluster condensates. Condensate states of more than three alpha-particles do not exist due to couplings to other degrees of freedom.

  4. Selective flow path alpha particle detector and method of use

    DOEpatents

    Orr, Christopher Henry (Sellafield, Seascale, Cumbria, GB); Luff, Craig Janson (Sellafield, Seascale, Cumbria, GB); Dockray, Thomas (Sellafield, Seascale, Cumbria, GB); Macarthur, Duncan Whittemore (P.O. Box 1663, Los Alamos, NM 87545)

    2002-01-01

    A method and apparatus for monitoring alpha contamination are provided in which ions generated in the air surrounding the item, by the passage of alpha particles, are moved to a distant detector location. The parts of the item from which ions are withdrawn can be controlled by restricting the air flow over different portions of the apparatus. In this way, detection of internal and external surfaces separately, for instance, can be provided. The apparatus and method are particularly suited for use in undertaking alpha contamination measurements during the commissioning operations.

  5. Morphology and dynamics of craterlike structures created by recoiling elongated particles.

    PubMed

    Engelsberg, M; de Souza, R E; Campello, S L

    2011-10-01

    We study the morphology and dynamics of craterlike structures formed when free-falling, randomly oriented, elongated particles bounce off a flat surface in a single particle scattering mode. The origin of a sharply defined rim with its associated structure, the factors determining the rim diameter, and the scaling of the diameter with impact velocity are examined. The probability distribution of rebounding particle ranges is calculated for a particular example and shown to provide a precursor description of structure formation. PMID:22181139

  6. Alpha and recoil track detection in poly(methyl methacrylate) (PMMA)—Towards a method for in vitro assessment of radiopharmaceuticals internalized in cancer cells

    SciTech Connect

    Myhra, S., E-mail: sverre.myhra@materials.ox.ac.uk; Chakalova, R. [Oxford University Begbroke Science Park, University of Oxford, Oxford (United Kingdom)] [Oxford University Begbroke Science Park, University of Oxford, Oxford (United Kingdom); Falzone, N. [MRC/CRUK Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, United Kingdom and Department of Biomedical Science, Tshwane University of Technology, Pretoria (South Africa)] [MRC/CRUK Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, United Kingdom and Department of Biomedical Science, Tshwane University of Technology, Pretoria (South Africa)

    2014-03-15

    A method for detection and characterization of single MeV ?-particle and recoil tracks in PMMA photoresist by atomic force microscopy (AFM) analysis has been demonstrated. The energy deposition along the track is shown to lead to a latent pattern in the resist due to contrast reversal. It has been shown that the pattern, consisting of conical spikes, can be developed by conventional processing as a result of the dissolution rate of poly(methyl methacrylate) (PMMA) being greater than that for the modified material in the cylindrical volume of the track core. The spikes can be imaged and counted by routine AFM analysis. Investigations by angular-resolved near-grazing incidence reveal additional tracks that correspond to recoil tracks. The observations have been correlated with modelling, and shown to be in qualitative agreement with prevailing descriptions of collision cascades. The results may be relevant to technologies that are based on detection and characterization of single energetic ions. In particular, the direct visualization of the collision cascade may allow more accurate estimates of the actual interaction volume, which in turn will permit more precise assessment of dose distribution of ?-emitting radionuclides used for targeted radiotherapy. The results could also be relevant to other diagnostic or process technologies based on interaction of energetic ions with matter.

  7. Validating modeling assumptions of alpha particles in electrostatic turbulence

    NASA Astrophysics Data System (ADS)

    Wilkie, G. J.; Abel, I. G.; Highcock, E. G.; Dorland, W.

    2015-06-01

    To rigorously model fast ions in fusion plasmas, a non-Maxwellian equilibrium distribution must be used. In this work, the response of high-energy alpha particles to electrostatic turbulence has been analyzed for several different tokamak parameters. Our results are consistent with known scalings and experimental evidence that alpha particles are generally well confined: on the order of several seconds. It is also confirmed that the effect of alphas on the turbulence is negligible at realistically low concentrations, consistent with linear theory. It is demonstrated that the usual practice of using a high-temperature Maxwellian, while previously shown to give an adequate order-of-magnitude estimate of the diffusion coefficient, gives incorrect estimates for the radial alpha particle flux, and a method of correcting it in general is provided. Furthermore, we see that the timescales associated with collisions and transport compete at moderate energies, calling into question the assumption that alpha particles remain confined to a flux surface that is used in the derivation of the slowing-down distribution.

  8. Mutagenic effects of alpha particles in normal human skin fibroblasts

    SciTech Connect

    Chen, D.J.; Carpenter, S.; Hanks, T. [Los Alamos National Lab., NM (United States)

    1992-12-31

    Alpha-irradiation to the bronchial airways from inhaled radon progeny increases the risk of developing lung cancer. The molecular mechanism of radon-induced lung cancer is not clear, but one of the most important genetic effects of ionizing radiation is the induction of gene mutation. Mutations, especially those associated with visible chromosome abnormalities in humans, have been associated with cancer. Therefore, our objective is to use a well-defined model system to determine the mutagenic potential of alpha particles in normal human skin cells and to define this action at the molecular level. Normal human skin fibroblasts were irradiated with alpha particles (3.59 MeV, LET 115 keV {mu}m{sup {minus}1}) emitted from the decay of {sup 238}Pu. Mutagenicity was determined at the X-linked hypoxanthine guanine phosphoribosyl transferase (HPRT) locus. Results from this study indicate that beta particles were more efficient in mutation induction than gamma rays. Based on the initial slopes of the dose-response curves, the RBE for mutation is about 8 for alpha particles. HPRT-deficient mutants which are resistant to 6-thioguanine have been isolated and analyzed by the Southern blot technique. To date, we have characterized 69 gamma-ray-induced and 195 alpha-particle-induced HPRT-deficient mutants. Our data indicate that more than 50% of all gamma-ray-induced mutants have band patterns identical to that observed for the normal structural HPRT gene, whereas the remaining mutants (45%) contain either a rearrangement, partial deletion, or total deletion of the HPRT gene. In contrast, only 30% of alpha-particle-induced human HPRT mutants contain a normal Southern blot pattern, and about 50% indicate total deletion of the HPRT gene. Our results support the notion that high-LET radiation produces more unrepaired or misrepaired DNA damage than do gamma rays.

  9. AlphaRad, a new integrated CMOS System-On-Chip for high efficiency alpha particle counting.

    E-print Network

    Paris-Sud XI, Université de

    1 AlphaRad, a new integrated CMOS System-On-Chip for high efficiency alpha particle counting. D * corresponding author : daniel.husson@ires.in2p3.fr Abstract An integrated System-on-Chip (SoC) has been designed; #12;2 Key words: Solid state detectors; System-on-chip; Alpha particles; Neutrons. The field

  10. Optical appearance of alpha particle tracks in CR39 SSNTD

    Microsoft Academic Search

    K. N. Yu; H. H. W. Lee; A. W. T. Wong; Y. L. Law; S. F. L. Cheung; D. Nikezic; F. M. F. Ng

    2007-01-01

    A ray tracing method based on geometrical optics was used to study the tracks from alpha particles with different energies and with an incident angle of 50°. The transmission operation mode of the microscope is simulated. Considering the distribution of light intensities from the tracks, the mean and the 80% percentile gray levels from real experiments are proposed as quantitative

  11. Modelling and Dosimetry for Alpha-Particle Therapy

    PubMed Central

    Sgouros, George; Hobbs, Robert F.; Song, Hong

    2015-01-01

    As a consequence of the high potency and short range of alpha-particles, radiopharmaceutical therapy with alpha-particle emitting radionuclides is a promising treatment approach that is under active pre-clinical and clinical investigation. To understand and predict the biological effects of alpha-particle radiopharmaceuticals, dosimetry is required at the micro or multi-cellular scale level. At such a scale, highly non-uniform irradiation of the target volume may be expected and the utility of a single absorbed dose value to predict biological effects comes into question. It is not currently possible to measure the pharmacokinetic input required for micro scale dosimetry in humans. Accordingly, pre-clinical studies are required to provide the pharmacokinetic data for dosimetry calculations. The translation of animal data to the human requires a pharmacokinetic model that links macro- and micro-scale pharmacokinetics thereby enabling the extrapolation of micro-scale kinetics from macroscopic measurements. These considerations along with a discussion of the appropriate physical quantity and related units for alpha-particle radiopharmaceutical therapy are examined in this review. PMID:22201712

  12. Alpha-particle physics in the tokamak fusion test reactor DT experiment

    Microsoft Academic Search

    S. J. Zweben; V. Arunasalam; S. H. Batha; R. V. Budny; C. E. Bush; S. Cauffman; C. S. Chang; Z. Chang; C. Z. Cheng; D. S. Darrow; R. O. Dendy; H. H. Duong; N. J. Fisch; E. D. Fredrickson; R. K. Fisher; R. J. Fonck; G. Y. Fu; V. Goloborod'ko; N. Gorelenkov; R. J. Hawryluk; R. Heeter; W. W. Heidbrink; H. W. Herrmann; M. Herrmann; D. W. Johnson; J. Machuzak; R. Majeski; K. M. McGuire; G. McKee; S. S. Medley; H. E. Mynick; R. Nazikian; M. P. Petrov; M. H. Redi; S. Reznik; J. Rogers; G. Schilling; D. A. Spong; J. D. Strachan; B. C. Stratton; E. Synakowski; G. Taylor; S. Wang; R. B. White; K. L. Wong; V. Yavorski

    1997-01-01

    A summary is presented of recent alpha-particle experiments on the tokamak fusion test reactor. Alpha particles are generally well confined in MHD-quiescent discharges, and alpha heating of electrons has been observed. The theoretically predicted toroidicity-induced Alfvén eigenmode has been seen in discharges of <= 1 MW of alpha power, but only in plasmas with weak magnetic shear.

  13. Control of alpha-particle transport by ion cyclotron resonance heating

    SciTech Connect

    Chang, C.S.; Imre, K.; Weitzner, H.; Colestock, P. (Princeton Univ., NJ (United States). Plasma Physics Lab.)

    1990-12-01

    In this paper control of radial alpha-particle transport by using ion cyclotron range of frequency (ICRF) waves is investigated in a large-aspect-ratio tokamak geometry. Spatially inhomogeneous ICRF wave energy with properly selected frequencies and wave numbers can induce fast convective transports of alpha particles at the speed of order v{sub {alpha}} {approximately} (P{sub RF}/n{sub {alpha}}{epsilon}{sub 0}){rho}{sup p}, where R{sub RF} is the ICRF wave power density, n{sub {alpha}} is the alpha-particle density, {epsilon}{sub 0} is the alpha-particle birth energy, and {rho}{sub p} is the poloidal gyroradius of alpha particles at the birth energy. Application to International Thermonuclear Experimental Reactor (ITER) plasma is studied and possible antenna designs to control alpha-particle flux are discussed.

  14. Quality factors for alpha particles emitted in tissue

    NASA Technical Reports Server (NTRS)

    Borak, Thomas B.; Chatterjee, A. (Principal Investigator)

    2002-01-01

    A concept of a mean or dose averaged quality factor was defined in ICRP Publication 26 using relationships for quality factor as a function of LET. The concept of radiation weighting factors, wR, was introduced in ICRP Publication 60 in 1990. These are meant to be generalized factors that modify absorbed dose to reflect the risk of stochastic effects as a function of the quality of the radiation incident on the body or emitted by radioactivity within the body. The values of wr are equal to 20 for all alpha particles externally or internally emitted. This note compares the dose averaged quality factor for alpha particles originating in tissue using the old and revised recommendations for quality factor as a function of LET. The dose averaged quality factor never exceeds 20 using the old recommendations and is never less than 20 with the revised recommendations.

  15. A Novel Experiment to Investigate the Attenuation of Alpha Particles in Air

    ERIC Educational Resources Information Center

    Andrews, D. G. H.

    2008-01-01

    A simple student experiment investigating dependence on air pressure of the attenuation of alpha particles in air is described. An equation giving the pressure needed to absorb all alpha particles of a given energy is derived from the Bethe-Bloch formula. Results are presented for the attenuation of alpha particles from americium 241 and radium…

  16. Influence of Magnolol on the bystander effect induced by alpha-particle irradiation

    E-print Network

    Yu, K.N.

    Influence of Magnolol on the bystander effect induced by alpha-particle irradiation T.P.W. Wong, Hong Kong a r t i c l e i n f o Keywords: Bystander effect Alpha-particle CHO cells Magnolol a b s t r a c t In this work, the influence of Magnolol on the bystander effect in alpha-particle irradiated

  17. GaN-based PIN alpha particle detectors

    Microsoft Academic Search

    Guo Wang; Kai Fu; Chang-sheng Yao; Dan Su; Guo-guang Zhang; Jin-yan Wang; Min Lu

    GaN-based PIN alpha particle detectors are studied in this article. The electrical properties of detectors have been investigated, such as current–voltage (I–V) and capacitance–voltage (C–V). The reverse current of all detectors is in nA range applied at 30V, which is suitable for detector operation. The charge collection efficiency (CCE) is measured to be approximately 80% but the energy resolution is

  18. An alpha particle instrument with alpha, proton, and X-ray modes for planetary chemical analyses

    NASA Technical Reports Server (NTRS)

    Economou, T. E.; Turkevich, A. L.

    1976-01-01

    The interaction of alpha particles with matter is employed in a compact instrument that could provide rather complete in-situ chemical analyses of surfaces and thin atmospheres of extraterrestrial bodies. The instrument is a miniaturized and improved version of the Surveyor lunar instrument. The backscattering of alpha particles and (alpha, p) reactions provide analytical data on the light elements (carbon-iron). An X-ray mode that detects the photons produced by the alpha sources provides sensitivity and resolution for the chemical elements heavier than about silicon. The X-rays are detected by semiconductor detectors having a resolution between 150 and 250 eV at 5.9 keV. Such an instrument can identify and determine with good accuracy 99 percent of the atoms (except hydrogen) in rocks. For many trace elements, the detecting sensitivity is a few ppm. Auxiliary sources could be used to enhance the sensitivities for elements of special interest. The instrument could probably withstand the acceleration involved in semi-hard landings.

  19. The effects of alpha particle irradiation on stainless steel 

    E-print Network

    Shipp, John Douglas

    1999-01-01

    (1000), Pu 239, Pu 240, Am 241 +, deveta(1000), dev Jz, devflux, avgSae(1000) +, avgeta(1000), avg Jz, avgflux, stdSae(1000) +, stdeta(1000), std Jz, stdflux, particle(10), avgparticle, stdparticle, +sumparticle, Elow, Elo(10), devElo, stdElo, sum...THE EFFECTS OF ALPHA PARTICLE IRRADIATION ON STAINLESS STEEL A Thesis by JOHN DOUGLAS SHIPP Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE...

  20. Alpha-particle Measurements Needed for Burning Plasma Experiments

    SciTech Connect

    Kenneth M. Young

    2001-09-26

    The next major step in magnetic fusion studies will be the construction of a burning plasma (BP) experiment where the goals will be to achieve and understand the plasma behavior with the internal heating provided by fusion-generated alpha particles. Two devices with these physics goals have been proposed: the International Thermonuclear Experimental Reactor (ITER) and the Fusion Ignition Research Experiment (FIRE). Extensive conceptual design work for the instrumentation to try to meet the physics demands has been done for these devices, especially ITER. This article provides a new look at the measurements specifically important for understanding the physics aspects of the alpha particles taking into account two significant events. The first is the completion of physics experiments on the Joint European Torus (JET) and the Tokamak Fusion Test Reactor (TFTR) with deuterium-tritium fueling with the first chances to study alpha physics and the second is the realization that relatively compact plasmas, making use of advanced tokamak plasma concepts, are the most probable route to burning plasmas and ultimately a fusion reactor.

  1. SPECIAL TOPIC: Alpha particle physics experiments in the Tokamak Fusion Test Reactor

    NASA Astrophysics Data System (ADS)

    Zweben, S. J.; Budny, R. V.; Darrow, D. S.; Medley, S. S.; Nazikian, R.; Stratton, B. C.; Synakowski, E. J.; Taylor, G.; TFTR Group

    2000-01-01

    Alpha particle physics experiments were done on TFTR during its DT run from 1993 to 1997. These experiments utilized several new alpha particle diagnostics and hundreds of DT discharges to characterize the alpha particle confinement and wave-particle interactions. In general, the results from the alpha particle diagnostics agreed with the classical single particle confinement model in MHD quiescent discharges. The alpha loss due to toroidal field ripple was identified in some cases, and the low radial diffusivity inferred for high energy alphas was consistent with orbit averaging over small scale turbulence. Finally, the observed alpha particle interactions with sawteeth, toroidal Alfvén eigenmodes and ICRF waves were approximately consistent with theoretical modelling. What was learned is reviewed and what remains to be understood is identified.

  2. Particle-Mesh Simulations of the Lyman-Alpha Forest

    E-print Network

    A. Meiksin; M. White

    2000-08-15

    Numerical hydrodynamical simulations have proven a successful means of reproducing many of the statistical properties of the Lyman-Alpha forest as measured in high redshift quasar spectra. Pseudo-hydrodynamical methods based only on simulating the dark matter component have been claimed to yield a comparable level of success. We investigate the degree to which two pseudo-methods, with and without allowing for a pseudo-gas pressure, are able to match the predictions of fully hydrodynamical plus dark matter simulations. We also address the requirements for convergence to the statistics of the spectra and the inferred properties of the Lyman-Alpha forest as a function of resolution and box size. Generally we find it is possible to reach agreement with full hydrodynamic simulations at the 10% level in the cumulative distributions of the flux and absorption line parameter statistics for readily achievable particle and grid numbers, but difficult to do much better.

  3. GaN-based PIN alpha particle detectors

    NASA Astrophysics Data System (ADS)

    Wang, Guo; Fu, Kai; Yao, Chang-sheng; Su, Dan; Zhang, Guo-guang; Wang, Jin-yan; Lu, Min

    2012-01-01

    GaN-based PIN alpha particle detectors are studied in this article. The electrical properties of detectors have been investigated, such as current-voltage ( I- V) and capacitance-voltage ( C- V). The reverse current of all detectors is in nA range applied at 30 V, which is suitable for detector operation. The charge collection efficiency (CCE) is measured to be approximately 80% but the energy resolution is calculated to be about 40% mostly because the intrinsic layer is not sufficiently thick enough.

  4. Radiolytic gas production in the alpha particle degradation of plastics

    SciTech Connect

    Reed, D.T.; Hoh, J.; Emery, J. (Argonne National Lab., IL (United States)); Hobbs, D. (Westinghouse Savannah River Co., Aiken, SC (United States))

    1992-01-01

    Net gas generation due to alpha particle irradiation of polyethylene and polyvinyl chloride was investigated. Experiments were performed in an air environment at 30, 60, and 100{degree}C. The predominant radiolytic degradation products of polyethylene were hydrogen and carbon dioxide with a wide variety of trace organic species noted. Irradiation of polyvinyl chloride resulted in the formation of HCl in addition to the products observed for polyethylene. For both plastic materials, a strong enhancement of net yields was noted at 100{degree}C.

  5. Radiolytic gas production in the alpha particle degradation of plastics

    SciTech Connect

    Reed, D.T.; Hoh, J.; Emery, J. [Argonne National Lab., IL (United States); Hobbs, D. [Westinghouse Savannah River Co., Aiken, SC (United States)

    1992-05-01

    Net gas generation due to alpha particle irradiation of polyethylene and polyvinyl chloride was investigated. Experiments were performed in an air environment at 30, 60, and 100{degree}C. The predominant radiolytic degradation products of polyethylene were hydrogen and carbon dioxide with a wide variety of trace organic species noted. Irradiation of polyvinyl chloride resulted in the formation of HCl in addition to the products observed for polyethylene. For both plastic materials, a strong enhancement of net yields was noted at 100{degree}C.

  6. Two-electron capture from helium by fast [alpha] particles

    SciTech Connect

    Belkic, D.; Mancev, I.; Mudrinic, M. (University of Stockholm, Atomic Physics, Frescativaegen 24, S-104 05 Stockholm (Sweden) Institute of Physics, P.O. Box 57, 11001 Belgrade (Yugoslavia) Department of Physics, University of Nis, P.O. Box 91, 18001 Nis (Yugoslavia))

    1994-05-01

    Two-electron capture from helium by fast [alpha] particles is investigated. Working within the four-body framework of scattering theory, we perform detailed computations for differential as well as total cross sections, by means of the second-order Born distorted-wave (BDW) approximation, and find good agreement with the available experimental data. We also report the results obtained by means of the continuum distorted-wave (CDW) method in both the four-body formalism and the independent-particle model. The former fails to reproduce the measurement, whereas the latter emerges as a satisfactory method for [alpha]-He double-charge exchange. The reported study of the electronic continuum intermediate states clearly indicates that double-charge exchange is remarkably sensitive to inclusion of these long-range Coulomb effects, even at incident energies at which the Thomas double scattering is completely unimportant. This is in sharp contrast to the familiar situation at the comparable energies encountered in treating single-electron transfer in ion-atom collisions.

  7. Profiles and parameters of tracks in the LR115 detector irradiated with alpha particles

    E-print Network

    Yu, K.N.

    Profiles and parameters of tracks in the LR115 detector irradiated with alpha particles D. Nikezic particles. Some differences between the behavior of CR39 and LR115 detectors are discussed. Track parameters have been calculated and plotted for the CR39 detector irradiated with alpha particles [11]. Another

  8. Alpha particle losses from Tokamak Fusion Test Reactor deuterium-tritium plasmas

    SciTech Connect

    Darrow, D.S.; Zweben, S.J. [Princeton Univ., NJ (United States). Plasma Physics Lab.] [Princeton Univ., NJ (United States). Plasma Physics Lab.; Batha, S. [Fusion Physics and Technology, Torrance, CA (United States)] [Fusion Physics and Technology, Torrance, CA (United States)

    1996-01-01

    Because alpha particle losses can have a significant influence on tokamak reactor viability, the loss of deuterium-tritium alpha particles from the Tokamak Fusion Test Reactor (TFTR) has been measured under a wide range of conditions. In TFTR, first orbit loss and stochastic toroidal field ripple diffusion are always present. Other losses can arise due to magnetohydrodynamic instabilities or due to waves in the ion cyclotron range of frequencies. No alpha particle losses have yet been seen due to collective instabilities driven by alphas. Ion Bernstein waves can drive large losses of fast ions from TFTR, and details of those losses support one element of the alpha energy channeling scenario.

  9. A self-consistent theory of collective alpha particle losses induced by Alfvenic turbulence

    SciTech Connect

    Biglari, H. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Diamond, P.H. [California Univ., San Diego, La Jolla, CA (United States). Dept. of Physics

    1992-01-01

    The nonlinear dynamics of kinetic Alfven waves, resonantly excited by energetic ions/alpha particles, is investigated. It is shown that {alpha}-particles govern both linear instability and nonlinear saturation dynamics, while the background MHD turbulence results only in a nonlinear real frequency shift. The most efficient saturation mechanism is found to be self-induced profile modification. Expressions for the fluctuation amplitudes and the {alpha}-particle radial flux are self-consistently derived. The work represents the first self-consistent, turbulent treatment of collective {alpha}-particle losses by Alfvenic fluctuations.

  10. Anomalous loss of DT alpha particles in the Tokamak Fusion Test Reactor

    SciTech Connect

    Herrmann, H.W.

    1997-09-01

    An escaping alpha collector probe has been developed for TFTR`s DT phase. Energy distributions of escaping alphas have been determined by measuring the range of {alpha}-particles implanted into nickel foils located within the alpha collector. Results at 1.0 MA of plasma current are in good agreement with predictions for first orbit alpha loss. Results at 1.8 MA, however, show a significant anomalous loss of partially thermalized alphas (in addition to the expected first orbit loss), which is not observed with the lost alpha scintillator detectors in DT plasmas, but does resemble the anomalous delayed loss seen in DD plasmas. None of the candidate explanations proposed thus far are fully consistent with the anomalous loss observations. An experiment designed to study the effect of plasma major radius shifts on {alpha}-particle loss has led to a better understanding of {alpha}-particle dynamics in tokamaks. Intuitively, one might suppose that confined marginally passing {alpha}-particles forced to move toward higher magnetic field during an inward major radius shift (i.e., compression) would mirror and become trapped particles, leading to increased alpha loss. Such an effect was looked for during the shift experiment, however, no significant changes in alpha loss to the 90{degree} lost alpha scintillator detector were observed during the shifts. It is calculated that the energy gained by an {alpha}-particle during the inward shift is sufficient to explain this result. However, an unexpected loss of partially thermalized {alpha}-particles near the passing/trapped boundary was observed to occur between inward and outward shifts at an intermediate value of plasma current (1.4 MA). This anomalous loss feature is not yet understood.

  11. Enhanced production of low energy electrons by alpha particle impact.

    PubMed

    Kim, Hong-Keun; Titze, Jasmin; Schöffler, Markus; Trinter, Florian; Waitz, Markus; Voigtsberger, Jörg; Sann, Hendrik; Meckel, Moritz; Stuck, Christian; Lenz, Ute; Odenweller, Matthias; Neumann, Nadine; Schössler, Sven; Ullmann-Pfleger, Klaus; Ulrich, Birte; Fraga, Rui Costa; Petridis, Nikos; Metz, Daniel; Jung, Annika; Grisenti, Robert; Czasch, Achim; Jagutzki, Ottmar; Schmidt, Lothar; Jahnke, Till; Schmidt-Böcking, Horst; Dörner, Reinhard

    2011-07-19

    Radiation damage to living tissue stems not only from primary ionizing particles but to a substantial fraction from the dissociative attachment of secondary electrons with energies below the ionization threshold. We show that the emission yield of those low energy electrons increases dramatically in ion-atom collisions depending on whether or not the target atoms are isolated or embedded in an environment. Only when the atom that has been ionized and excited by the primary particle impact is in immediate proximity of another atom is a fragmentation route known as interatomic Coulombic decay (ICD) enabled. This leads to the emission of a low energy electron. Over the past decade ICD was explored in several experiments following photoionization. Most recent results show its observation even in water clusters. Here we show the quantitative role of ICD for the production of low energy electrons by ion impact, thus approaching a scenario closer to that of radiation damage by alpha particles: We choose ion energies on the maximum of the Bragg peak where energy is most efficiently deposited in tissue. We compare the electron production after colliding He(+) ions on isolated Ne atoms and on Ne dimers (Ne(2)). In the latter case the Ne atom impacted is surrounded by a most simple environment already opening ICD as a deexcitation channel. As a consequence, we find a dramatically enhanced low energy electron yield. The results suggest that ICD may have a significant influence on cell survival after exposure to ionizing radiation. PMID:21730184

  12. Realizing the potential of the Actinium-225 radionuclide generator in targeted alpha particle therapy applications.

    PubMed

    Miederer, Matthias; Scheinberg, David A; McDevitt, Michael R

    2008-09-01

    Alpha particle-emitting isotopes have been proposed as novel cytotoxic agents for augmenting targeted therapy. Properties of alpha particle radiation such as their limited range in tissue of a few cell diameters and their high linear energy transfer leading to dense radiation damage along each alpha track are promising in the treatment of cancer, especially when single cells or clusters of tumor cells are targeted. Actinium-225 (225 Ac) is an alpha particle-emitting radionuclide that generates 4 net alpha particle isotopes in a short decay chain to stable 209 Bi, and as such can be described as an alpha particle nanogenerator. This article reviews the literature pertaining to the research, development, and utilization of targeted 225 Ac to potently and specifically affect cancer. PMID:18514364

  13. A CMOS integrated pulse mode alpha-particle counter for application in radon monitoring

    SciTech Connect

    Ahmed, A.; Walkey, D.J.; Tarr, N.G. [Carleton Univ., Ottawa, Ontario (Canada). Dept. of Electronics] [Carleton Univ., Ottawa, Ontario (Canada). Dept. of Electronics

    1997-06-01

    A custom integrated circuit for detecting alpha particles for application in the monitoring of radon has been designed and tested. The design uses the reverse-biased well to a substrate capacitance of a p-n junction in a conventional CMOS process as a sense capacitor for incident alpha particles. A simple CMOS inverter is used as an analog amplifier to detect the small potential change induced by an alpha-particle strike on the sense capacitor. The design was implemented in a 1.2-{micro}m conventional CMOS process with a sense capacitor area of 110 {micro}m{sup 2}. Tests carried out under vacuum conditions using a calibrated {sup 241}Am alpha-particle source showed an output voltage swing of {ge}2.0 V for an alpha event. The detector is also shown to have good immunity to noise and high-quantum efficiency for alpha particles.

  14. Relative biological effectiveness of alpha particles at radon exposure.

    PubMed

    Zhukovsky, M; Bastrikova, N; Vasilyev, A

    2015-06-01

    The relative biological effectiveness (RBE) of alpha particles at radon exposure is estimated by comparison of radiation risks at external gamma exposure and radon exposure in different situations. For external gamma exposure, the BEIR VII model of radiation risk assessment was used. For occupational and indoor radon exposure, models such as BEIR VI, WISMUT, Tomasek's and combined miners population were considered. It was demonstrated that RBE values are strongly dependent on models of radiation risk assessment used for RBE calculation, sex of exposed peoples and age at the exposure. The average values of RBE in dependence on model of risk assessment choice are in the range from 1.5 to 12.0 for males and in the range from 0.34 to 2.7 for females. PMID:25979745

  15. A Double Scattering Analytical Model For Elastic Recoil Detection Analysis

    SciTech Connect

    Barradas, N. P.; Lorenz, K.; Alves, E. [Instituto Tecnologico e Nuclear, E.N. 10, Sacavem 2686-953 (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); Darakchieva, V. [Instituto Tecnologico e Nuclear, E.N. 10, Sacavem 2686-953 (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); IFM, Linkoeping University, SE-581 83 Linkoeping (Sweden)

    2011-06-01

    We present an analytical model for calculation of double scattering in elastic recoil detection measurements. Only events involving the beam particle and the recoil are considered, i.e. 1) an ion scatters off a target element and then produces a recoil, and 2) an ion produces a recoil which then scatters off a target element. Events involving intermediate recoils are not considered, i.e. when the primary ion produces a recoil which then produces a second recoil. If the recoil element is also present in the stopping foil, recoil events in the stopping foil are also calculated. We included the model in the standard code for IBA data analysis NDF, and applied it to the measurement of hydrogen in Si.

  16. Accounting for Recoil Effects in Geochronometers: A New Model Approach

    NASA Astrophysics Data System (ADS)

    Lee, V. E.; Huber, C.

    2012-12-01

    A number of geologically important chronometers are affected by, or owe their utility to, the "recoil effect". This effect describes the physical displacement of a nuclide due to energetic nuclear processes such as radioactive alpha decay (as in the case of various parent-daughter pairs in the uranium-series decay chains, and Sm-Nd), as well as neutron irradiation (in the case of the methodology for the 40Ar/39Ar dating method). The broad range of affected geochronometers means that the recoil effect can impact a wide range of dating method applications in the geosciences, including but not limited to: Earth surface processes, paleoclimate, volcanic processes, and cosmochemistry and planetary evolution. In particular, the recoil effect can have a notable impact on the use of fine grains (silt- and clay-sized particles) for geochronometric dating purposes. This is because recoil-induced loss of a nuclide from the surfaces of a grain can create an isotopically-depleted outer rind, and for small grains, this depleted rind can be volumetrically significant. When this recoil loss is measurable and occurs in a known time-dependent fashion, it can usefully serve as the basis for chronometers (such as the U-series comminution age method); in other cases recoil loss from fine particles creates an unwanted deviation from expected isotope values (such as for the Ar-Ar method). To improve both the accuracy and precision of ages inferred from geochronometric systems that involve the recoil of a key nuclide from small domains, it is necessary to quantify the magnitude of the recoil loss of that particular nuclide. It is also necessary to quantitatively describe the effect of geological processes that can alter the outer surface of grains, and hence the isotopically-depleted rind. Here we present a new mathematical and numerical model that includes two main features that enable enhanced accuracy and precision of ages determined from geochronometers. Since the surface area of the dated grain is a major control on the magnitude of recoil loss, the first feature is the ability to calculate recoil effects on isotopic compositions for realistic, complex grain shapes and surface roughnesses. This is useful because natural grains may have irregular shapes that do not conform to simple geometric descriptions. Perhaps more importantly, the surface area over which recoiled nuclides are lost can be significantly underestimated when grain surface roughness is not accounted for, since the recoil distances can be of similar characteristic lengthscales to surface roughness features. The second key feature is the ability to incorporate dynamical geologic processes affecting grain surfaces in natural settings, such as dissolution and crystallization. We describe the model and its main components, and point out implications for the geologically-relevant chronometers mentioned above.

  17. Self-consistent study of the alpha particle driven TAE mode

    SciTech Connect

    Wu, Y.; White, R.B.

    1994-04-01

    The interaction of high energy particles with an Alfven eigenmode is investigated self-consistently by using a realistic kinetic dispersion relation. All important poloidal mode numbers and their radial mode profiles as calculated with the NOVA-K code are included. A Hamiltonian guiding center code is used to simulate the alpha particle motion. The numerical simulations include particle orbit width, nonlinear particle dynamics and the effects of the modes on the particles. Modification of the particle distribution leading to mode saturation is observed. Particle loss is limited to devices in which the alpha particle gyro radius is a significant fraction of the minor radius.

  18. Anomalous Loss of DT Alpha Particles in the Tokamak Fusion Test Reactor

    SciTech Connect

    Herrmann, Hans W.

    1997-06-01

    Princeton's Tokamak Fusion Test Reactor (TFTR) is the first experimental fusion device to routinely use tritium to study the deuterium-tritium (DT) fusion reaction,allowing the first systematic study of DT alpha particles in tokamak plasmas. A crucial aspect of alpha-particle physics is the fraction of alphas that escape from the plasma, particularly since these energetic particles can do severe damage to the first wall of a reactor. An escaping alpha collector probe has been developed for TFTR's DT phase. Energy distributions of escaping alphas have been determined by measuring the range of alpha-particles implanted into nickel foils located within the alpha collector. Results at 1.0 MA of plasma current are in good agreement with predictions for first orbit alpha loss. Results at 1.8 MA, however, show a significant anomalous loss of partially thermalized alphas (in addition to the expected first orbit loss), which is not observed with the lost alpha scintillator detectors in DT plasmas, but does resemble the anomalous "delayed" loss seen in DD plasmas. None of the candidate explanations proposed thus far are fully consistent with the anomalous loss observations. An experiment designed to study the effect of plasma major radius shifts on alpha-particle loss has led to a better understanding of alpha-particle dynamics in tokamaks. Intuitively, one might suppose that confined marginally passing alpha-particles forced to move toward higher magnetic field during an inward major radius shift (i.e. compression) would mirror and become trapped particles, leading to increased alpha loss. Such an effect was looked for during the shift experiment, however, no significant changes in alpha loss to the 90 degree lost alpha scintillator detector were observed during the shifts. It is calculated that the energy gained by an alpha-particle during the inward shift is sufficient to explain this result. However, an unexpected loss of partially thermalized alpha-particles near the passing/trapped boundary was observed to occur between inward and outward shifts at an intermediate value of plasma current (1.4 MA). This anomalous loss feature is not yet understood.

  19. Enhanced homologous recombination is induced by alpha-particle radiation in somatic cells of Arabidopsis thaliana

    NASA Astrophysics Data System (ADS)

    Bian, Po; Liu, Ping; Wu, Yuejin

    Almost 9 percent of cosmic rays which strike the earth's atmosphere are alpha particles. As one of the ionizing radiations (IR), its biological effects have been widely studied. However, the plant genomic instability induced by alpha-particle radiation was not largely known. In this research, the Arabidopsis thaliana transgenic for GUS recombination substrate was used to evaluate the genomic instability induced by alpha-particle radiation (3.3MeV). The pronounced effects of systemic exposure to alpha-particle radiation on the somatic homologous recombination frequency (HRF) were found at different doses. The 10Gy dose of radiation induced the maximal HRF which was 1.9-fold higher than the control. The local radiation of alpha-particle (10Gy) on root also resulted in a 2.5-fold increase of somatic HRF in non-radiated aerial plant, indicating that the signal(s) of genomic instability was transferred to non-radiated parts and initiated their genomic instability. Concurrent treatment of seedlings of Arabidopsis thaliana with alpha-particle and DMSO(ROS scavenger) both in systemic and local radiation signifi- cantly suppressed the somatic HR, indicating that the free radicals produced by alpha-particle radiation took part in the production of signal of genomic instability rather than the signal transfer. Key words: alpha-particle radiation, somatic homologous recombination, genomic instability

  20. A global 2.5-dimensional three fluid solar wind model with alpha particles

    Microsoft Academic Search

    Bo Li; Xing Li; Nicolas Labrosse

    2006-01-01

    A global 2.5-dimensional three fluid solar wind model is presented. Two ion species, namely protons and alpha particles, are heated by an empirical energy flux while electrons are heated by the classical heat flux and Coulomb coupling with ions. It is found that for a reasonable relative speed between alpha particles and protons at 1 AU to be achieved, the

  1. WIND Measurements of Proton and Alpha Particle Flow and Number Density J. T. Steinberg

    E-print Network

    Richardson, John

    for investigating the interplanetary edium. The solar wind experiment (SWE) on WIND e e includes 2 Faraday cup-alpha particle differential flow can s a be determined. We present early SWE Faraday cup result nd compare proton detectors for measuring th nergy/charge spectrum of solar wind protons and alpha f t particles. The Faraday

  2. Ion Densities and Particle Charges for Alpha Ionization in an Aerosol Atmosphere: Columnar Recombination Corrections

    Microsoft Academic Search

    Y. S. Mayya; W. Holländer

    1995-01-01

    Ionization by alpha sources in an environment containing small aerosol particles is of interest in aerosol neutralizes, particle chargers and atmospheric electricity. It is known that the conventional ion-balance equation is inadequate in describing the bulk ion densities for alpha sources in view of the columnar recombination process. An earlier self-consistent formulation to include this effect is extended to the

  3. Simulation of Alpha Particles in Rotating Plasma Interacting with a Stationary Ripple

    SciTech Connect

    Abraham J. Fetterman and Nathaniel J. Fisch

    2011-01-11

    Superthermal ExB rotation can provide magnetohydrodynamic (MHD) stability and enhanced confinement to axisymmetric mirrors. However, the rotation speed has been limited by phenomena at end electrodes. A new prediction is that rotation might instead be produced using a magnetic ripple and alpha particle kinetic energy, in an extension of the alpha channeling concept. The interaction of alpha particles with the ripple results in visually interesting and practically useful orbits.

  4. Experimental determination of LR115 detector efficiency for exposure to alpha particles

    Microsoft Academic Search

    D Marocco; F Bochicchio

    2001-01-01

    The alpha particle detection efficiency of LR-115 detectors has been measured against alpha particle energy E and incidence angle ? (with respect to the normal to the detector surface), using an experimental apparatus with an 241Am alpha source and air in a pressure-controlled chamber as the degrading medium, and a spark-counter for counting tracks. About 200 LR-115 detectors were exposed

  5. Use of /sup 3/He/sup + +/ ICRF minority heating to simulate alpha particle heating

    DOEpatents

    Post, D.E. Jr.; Hwang, D.Q.; Hovey, J.

    1983-11-16

    It is an object of the present invention to provide a better understanding of alpha particle behavior in a magnetically confined, energetic plasma. Another object of the present invention is to provide an improved means and method for studying and measuring the energy distribution of heated alpha particles in a confined plasma. Yet another object of the present invention is to permit detailed analysis of energetic alpha particle behavior in a magnetically confined plasma for use in near term fusion reactor experiments. A still further object of the present invention is to simulate energetic alpha particle behavior in a deuterium-tritium plasma confined in a fusion reactor without producing the neutron activation associated with the thus produced alpha particles.

  6. Statistical-Model Calculation of the Angular Distributions of (alpha, n) Reaction Products

    Microsoft Academic Search

    D. G. Swanson; N. T. Porile

    1970-01-01

    A calculation of the angular distribution of recoil products resulting from compound nuclear (alpha, n) reactions has been programmed on the basis of the spin-dependent statistical theory of nuclear reactions. The program, which is based on the Monte Carlo technique, considers the emission of neutrons, protons, alpha particles, and gamma rays, and uses either the Fermi-gas or the superconductor model

  7. Angular distribution of {alpha} particles from oriented {sup 253,254}Es and {sup 255}Fm nuclei

    SciTech Connect

    Severijns, N.; Golovko, V.V.; Kraev, I.S.; Phalet, T. [Instituut voor Kern- en Stralingsfysica, K.U. Leuven, B-3001 Leuven (Belgium); Belyaev, A.A.; Lukhanin, A.A.; Noga, V.I. [Kharkov Institute of Physics and Technology, 61108 Kharkov (Ukraine); Erzinkyan, A.L.; Parfenova, V.P. [Institute of Nuclear Physics, Moscow State University, 119992 Moscow (Russian Federation); Eversheim, P.-D.; Herzog, P.; Tramm, C. [Helmholtz Institute fuer Strahlen- und Kernphysik, Universitaet Bonn, D-53115 Bonn (Germany); Filimonov, V.T.; Toporov, Yu.G.; Zotov, E. [Research Institute for Atomic Reactors, 433510 Dimitrovgrad-10 (Russian Federation); Gurevich, G.M.; Rusakov, A.V. [Institute for Nuclear Research, Russian Academy of Sciences, 119312, Moscow (Russian Federation); Vyachin, V.N. [RFNC All-Russian Scientific Research Institute of Experimental Physics, 607190 Sarov (Russian Federation); Zakoucky, D. [Nuclear Physics Institute, Academy of Sciences of Czech Republic, CZ-25068 Rez (Czech Republic)

    2005-04-01

    The anisotropy in the angular distribution of {alpha} particles from oriented {sup 253,254}Es and {sup 255}Fm nuclei, which are among the strongest deformed {alpha} emitters, was measured. Large {alpha} anisotropies have been observed for all three nuclei. The results are compared with calculations based on {alpha}-particle tunneling through a deformed Coulomb barrier.

  8. PPPL-3253, Preprint: June 1997, UC-420, 426, 427 Alpha Particle Loss in TFTR Deuterium-Tritium Plasmas

    E-print Network

    PPPL-3253, Preprint: June 1997, UC-420, 426, 427 Alpha Particle Loss in TFTR Deuterium-Tritium ions. This paper presents calculations of guiding-center code alpha particle orbit loss from deuterium-tritium

  9. Measurement of the Internal Magnetic Field of Plasmas using an Alpha Particle Source

    SciTech Connect

    S.J. Zweben; D.S. Darrow; P.W. Ross; J.L. Lowrance; G. Renda

    2004-05-13

    The internal magnetic fields of plasmas can be measured under certain conditions from the integrated v x B deflection of MeV alpha particles emitted by a small radioactive source. This alpha source and large-area alpha particle detector would be located inside the vacuum vessel but outside the plasma. Alphas with a typical energy of 5.5 MeV (241Am) can reach the center of almost all laboratory plasmas and magnetic fusion devices, so this method can potentially determine the q(r) profile of tokamaks or STs. Orbit calculations, background evaluations, and conceptual designs for such a vxB (or ''AVB'') detector are described.

  10. Feasibility study on the use of polyallyldiglycol-carbonate cell dishes in TUNEL assay for alpha particle radiobiological experiments

    E-print Network

    Yu, K.N.

    on polyallyldiglycol-carbonate (PADC) films to investigate the effects of alpha particles on HeLa cervix cancer cells to investigate the effects of alpha particles on HeLa cervix cancer cells. To directly provide evidence alpha particle hit positions. A special method involving ``base tracks'' for aligning the images of cell

  11. The Effects of Alpha Particle Confinement on Burning Plasma Tokamak Performance

    NASA Astrophysics Data System (ADS)

    Gormley, Robert P.

    In this thesis, three effects of alpha particle plasma interactions on the global performance of a fusion reactor are studied, namely, (i) the energy coupling efficiency of the fast alpha particles with the bulk plasma, (ii) the relationship between imperfect alpha energy coupling to the bulk plasma and the resultant alpha particle/helium ash fuel dilution; and (iii) the neoclassical bootstrap current induced by fusion born alpha particles calculated self-consistently with the plasma equilibrium. First, the ion drift kinetic equation for the high energy alpha particles is reduced from the exact five dimensional form to a two dimensional form in radius r and energy E (plus time t). The resulting slowing-down diffusion equation is solved by a multiple energy group method. A theoretically based anomalous diffusion coefficient D_sp{alpha}{an} is then introduced from a self-consistent alpha particle Alfven wave turbulence solution (by F. Gang), in which D_sp{alpha}{an } itself depends on the gradient in alpha density. The temporal and spatial behavior of eta_ alpha is analyzed for an ITER-CDA physics phase fusion reactor. We find that eta_ alpha can be as low as 0.95 depending on the plasma operating temperature. Next, the relationship between the alpha-particle power coupling efficiency and the actual alpha-particle power that is coupled with the bulk plasma is investigated, this time taking into account the concomitant helium ash accumulation. It is found that the coupled power varies less than linearly with eta_alpha and is, in fact, significantly depressed for eta_alpha near unity. Combining these effects with a thermal power balance shows that the high temperature "thermally stable" side of the ignition boundary is pushed toward lower temperatures if either D_alpha increases (which results in a lower eta_alpha) or the helium-ash confinement time lengthens. This is a consequence of strengthened fuel dilution and imperfect alpha power coupling. Implications on the thermal stability of a fusion reactor are also discussed. Lastly, we calculate the alpha particle induced bootstrap current produced, while retaining the effects of slowing-down drag, pitch-angle scattering, and arbitrary aspect ratio. The alpha drift kinetic equation is solved for the alpha bootstrap current density; and the resulting expression inserted into a simple cylindrical Ampere's Law. In addition, the alpha bootstrap current is more rigorously solved, self-consistently, with the full 2-D Grad-Shafranov equilibrium equations for three currently conceived tokamaks: TPX, ITER-CDA and ITER-EDA. In particular, the effect of varying plasma Zeff on the alpha bootstrap current is investigated. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617 -253-5668; Fax 617-253-1690.).

  12. WIND measurements of proton and alpha particle flow and number density

    NASA Technical Reports Server (NTRS)

    Steinberg, J. T.; Lazarus, A. J.; Ogilvie, J. T.; Lepping, R.; Byrnes, J.; Chornay, D.; Keller, J.; Torbert, R. B.; Bodet, D.; Needell, G. J.

    1995-01-01

    We propose to review measurements of the solar wind proton and alpha particle flow velocities and densities made since launch with the WIND SWE instrument. The SWE Faraday cup ion sensors are designed to be able to determine accurately flow vector directions, and thus can be used to detect proton-alpha particle differential flow. Instances of differential flow, and the solar wind features with which they are associated will be discussed. Additionally, the variability of the percentage of alpha particles as a fraction of the total solar wind ion density will be presented.

  13. MIRD Pamphlet No. 22 (Unabridged): Radiobiology and Dosimetry of alpha-Particle Emitters for Targeted Radionuclide Therapy

    SciTech Connect

    Sgouros, George; Roeske, John C.; McDevitt, Michael S.; Palm, Stig; Allen, Barry J.; Fisher, Darrell R.; Brill, Bertrand A.; Song, Hong; Howell, R. W.; Akabani, Gamal

    2010-02-28

    The potential of alpha-particle emitters to treat cancer has been recognized since the early 1900s. Advances in the targeted delivery of radionuclides, in radionuclide conjugation chemistry, and in the increased availability of alpha-emitters appropriate for clinical use have recently led to patient trials of alpha-particle-emitter labeled radiopharmaceuticals. Although alpha-emitters have been studied for many decades, their current use in humans for targeted therapy is an important milestone. The objective of this work is to review those aspects of the field that are pertinent to targeted alpha-particle-emitter therapy and to provide guidance and recommendations for human alpha-particle-emitter dosimetry.

  14. Alpha particle driven current and torque in ITER baseline scenarios with 3D perturbations

    NASA Astrophysics Data System (ADS)

    Snicker, A.; Asunta, O.; Ylitie, H.; Kurki-Suonio, T.; Schneider, M.; Pinches, S. D.

    2015-06-01

    In this paper three-dimensional (3D) kinetic Monte Carlo orbit-following simulations are carried out with the ASCOT code to estimate the alpha particle driven current and torque profiles in ITER baseline scenarios. Several different 3D magnetic field configurations, including TF ripple, ferritic inserts, test blanket modules and edge localized mode coil perturbations, are used in these simulations. The alpha particle current is found to be less than one percent for all configurations and scenarios. In axisymmetric magnetic field configurations, the collisional and j × B torque components cancel each other, whilst in non-axisymmetric cases, the total torque is nonzero. The total alpha driven torque is found to oppose that generated by the neutral beam injection particles and to be an order of magnitude smaller. Consequently, alpha particles will not significantly contribute to the plasma current nor act as a source of plasma rotation in the ITER baseline scenarios considered.

  15. Influence of rotation-induced nuclear deformation on. alpha. -particle evaporation spectra

    SciTech Connect

    Huizenga, J.R.; Behkami, A.N.; Govil, I.M.; Schroder, W.U.; Toke, J. (Department of Chemistry and Nuclear Structure Research Laboratory, University of Rochester, Rochester, New York 14627 (US))

    1989-08-01

    The shapes of {alpha}-particle spectra from hot, high-spin compound nuclei produced in energetic heavy-ion fusion reactions are analyzed within the framework of a statistical model. Contrary to claims made in the literature, good agreement is obtained between calculated and experimental spectra when the evaporation barrier of each nuclide in the complex cascade is assumed equal to its respective absorption channel barrier. The dependence of the shape of {alpha}-particle spectra on nuclear deformation is discussed both in terms of the transmission coefficients and the spin-dependent level density of deformed nuclei. For deformations of the magnitude given by the rotating liquid drop model, {alpha}-particle spectra and effective barriers are insensitive to whether deformed or spherical nucleus transmission coefficients are used. It is important, however, to include the deformation dependence in the nuclear level density. Model calculations indicate that the shape of {alpha}-particle spectra may be quite insensitive to large deformations.

  16. Direct and indirect effects of alpha-particle irradiations of human prostate tumor cells

    E-print Network

    Wang, Rong, Ph. D. Massachusetts Institute of Technology

    2005-01-01

    The objective of this project is to establish a model system to study the direct effect, the bystander effect and the combinational effect of alpha-particle irradiations of human prostate tumor cells, toward the goal of ...

  17. LIMITS ON ALPHA PARTICLE TEMPERATURE ANISOTROPY AND DIFFERENTIAL FLOW FROM KINETIC INSTABILITIES: SOLAR WIND OBSERVATIONS

    SciTech Connect

    Bourouaine, Sofiane; Verscharen, Daniel; Chandran, Benjamin D. G. [Space Science Center, University of New Hampshire, Durham, NH 03824 (United States)] [Space Science Center, University of New Hampshire, Durham, NH 03824 (United States); Maruca, Bennett A. [Space Science Laboratory, University of California, Berkeley, CA 94720 (United States)] [Space Science Laboratory, University of California, Berkeley, CA 94720 (United States); Kasper, Justin C., E-mail: s.bourouaine@unh.edu [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

    2013-11-01

    Previous studies have shown that the observed temperature anisotropies of protons and alpha particles in the solar wind are constrained by theoretical thresholds for pressure and anisotropy driven instabilities such as the Alfvén/ion-cyclotron (A/IC) and fast-magnetosonic/whistler (FM/W) instabilities. In this Letter, we use a long period of in situ measurements provided by the Wind spacecraft's Faraday cups to investigate the combined constraint on the alpha proton differential flow velocity and the alpha particle temperature anisotropy due to A/IC and FM/W instabilities. We show that the majority of the data are constrained to lie within the region of parameter space in which A/IC and FM/W waves are either stable or have extremely low growth rates. In the minority of observed cases in which the growth rate of the A/IC (FM/W) instability is comparatively large, we find relatively higher values of T {sub ?}/T {sub p} (T {sub ??}/T {sub ?p}) when the alpha proton differential flow velocity is small, where T {sub ?} and T {sub p} (T {sub ??} and T {sub ?p}) are the perpendicular (parallel) temperatures of alpha particles and protons. We conjecture that this observed feature might arise from preferential alpha particle heating which can drive the alpha particles beyond the instability thresholds.

  18. Limits on Alpha Particle Temperature Anisotropy and Differential Flow from Kinetic Instabilities: Solar Wind Observations

    NASA Astrophysics Data System (ADS)

    Bourouaine, Sofiane; Verscharen, Daniel; Chandran, Benjamin D. G.; Maruca, Bennett A.; Kasper, Justin C.

    2013-11-01

    Previous studies have shown that the observed temperature anisotropies of protons and alpha particles in the solar wind are constrained by theoretical thresholds for pressure and anisotropy driven instabilities such as the Alfvén/ion-cyclotron (A/IC) and fast-magnetosonic/whistler (FM/W) instabilities. In this Letter, we use a long period of in situ measurements provided by the Wind spacecraft's Faraday cups to investigate the combined constraint on the alpha proton differential flow velocity and the alpha particle temperature anisotropy due to A/IC and FM/W instabilities. We show that the majority of the data are constrained to lie within the region of parameter space in which A/IC and FM/W waves are either stable or have extremely low growth rates. In the minority of observed cases in which the growth rate of the A/IC (FM/W) instability is comparatively large, we find relatively higher values of T ?/T p (T ??/T ?p ) when the alpha proton differential flow velocity is small, where T ? and T p (T ?? and T ?p ) are the perpendicular (parallel) temperatures of alpha particles and protons. We conjecture that this observed feature might arise from preferential alpha particle heating which can drive the alpha particles beyond the instability thresholds.

  19. Modification of alpha-particle emission spectrum in beam-injected deuterium-tritium plasmas

    SciTech Connect

    Matsuura, H.; Nakao, Y. [Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Motooka, Fukuoka 819-0395 (Japan)

    2009-04-15

    The alpha ({alpha})-particle and neutron emission spectra in a deuterium-tritium plasma accompanied with neutral-beam-injection (NBI) heating are evaluated in a consistent way by solving the Boltzmann-Fokker-Planck equations for deuteron, triton, and {alpha}-particle simultaneously. It is shown that owing to the existence of non-Maxwellian tail component in fuel-ion distribution function due to NBI and/or nuclear elastic scattering, the generation rate of the energetic ({>=}4 MeV) {alpha}-particle increases significantly. When 20 MW intense deuterium beam with 1 MeV beam-injection energy is injected into an 800 m{sup 3} plasma (T{sub e}=10 keV, n{sub e}=6.2x10{sup 19} m{sup -3}), the enhancement of the fraction of the power carried by {alpha}-particles with energy above 4 (3.9) MeV to total {alpha}-particle power is almost twice (1.5 times) as much from the value for Gaussian distribution. A verification scenario for the modification of the emission spectrum by using the gamma ({gamma})-ray-generating {sup 9}Be({alpha},n{gamma}){sup 12}C reaction is also presented.

  20. Three sources and three components of success in detection of ultra-rare alpha decays at the Dubna Gas-Filled Recoil separator

    E-print Network

    Tsyganov, Y S

    2015-01-01

    General philosophy of procedure of detecting rare events in the recent experiments with 48Ca projectile at the Dubna Gas-Filled Recoil Separator(DGFRS) aimed to the synthesis of superheavy elements (SHE) has been reviewed. Specific instruments and methods are under consideration. Some historical sources of the successful experiments for Z=112-118 are considered too. Special attention is paid to application of method of active correlations in heavy-ion induced complete fusion nuclear reactions. Example of application in Z=115 experiment is presented. Brief description of the 243Am + 48Ca -> 291-x115+xn experiment is presented too. Some attention is paid to the role of chemical experiments in discoveries of SHEs. The DGFRS detection/monitoring system is presented in full firstly.

  1. Three sources and three components of success in detection of ultra-rare alpha decays at the Dubna Gas-Filled Recoil separator

    E-print Network

    Y. S. Tsyganov

    2015-06-05

    General philosophy of procedure of detecting rare events in the recent experiments with 48Ca projectile at the Dubna Gas-Filled Recoil Separator(DGFRS) aimed to the synthesis of superheavy elements (SHE) has been reviewed. Specific instruments and methods are under consideration. Some historical sources of the successful experiments for Z=112-118 are considered too. Special attention is paid to application of method of active correlations in heavy-ion induced complete fusion nuclear reactions. Example of application in Z=115 experiment is presented. Brief description of the 243Am + 48Ca -> 291-x115+xn experiment is presented too. Some attention is paid to the role of chemical experiments in discoveries of SHEs. The DGFRS detection/monitoring system is presented in full firstly.

  2. {alpha}-particle optical potentials for nuclear astrophysics (NA) and nuclear technology (NT)

    SciTech Connect

    Avrigeanu, V.; Avrigeanu, M. [Horia Hulubei National Institute for Physics and Nuclear Engineering, POBox MG-6, 077125 Magurele, Ilfov (Romania)

    2012-11-20

    The high precision of recent measurements for low-energy {alpha}-particle elastic-scattering as well as induced-reaction data makes possible the understanding of actual limits and possible improvement of the global optical model potentials parameters. Involvement of recent optical potentials for reliable description of both the elastic scattering and emission of {alpha}-particles, of equal interest for nuclear astrophysics (NA) and nuclear technology (NT) for fusion devices, is discussed in the present work.

  3. Alpha-particle interactions with nuclei at 12A GeV/c

    SciTech Connect

    Claesson, G.; Garpman, S.; Lund, I.; Otterlund, I.; Stenlund, E.; Soederstroem, K.; Bhalla, K.B.; Bharti, A.; Kumar, V.; Lokanathan, S.

    1986-05-01

    Pseudorapidity-density distributions of shower particles from 12A-GeV/c ..cap alpha..-emulsion interactions are presented. As compared to extrapolations from p-nucleus data, the central ..cap alpha..+(Ag,Br) interactions exhibit an excess of particles in the middle pseudorapidity region. The correlation between and can be understood within a wounded-nucleon model.

  4. Physical aspects of precise spectrometry of alpha-particles with silicon pn-junction detectors

    Microsoft Academic Search

    E. Verbitskaya; V. Eremin; N. Strokan; J. Kemmer; B. Schmidt; J. von Borany

    1994-01-01

    Investigations of energy and charge losses have been carried out for silicon planar alpha-particle detectors. The detectors were manufactured by an advanced technology, using ion implantation and various annealing temperatures. A detailed analysis of the recombination processes in alpha-particle tracks with a high electron-hole density and a measurement procedure for the main parameters of charge carrier loss have been developed.

  5. High-spin particle states in 151Sm studied with the (alpha, 3He) reaction

    Microsoft Academic Search

    G. Løvhøiden; J. R. Lien; J. C. Waddington; J. Rekstad; I. Espe; C. Gaarde; J. S. Larsen; S. van der Werf

    1981-01-01

    High-spin states have been located in 151Sm by means of the (alpha, 3He) reaction with 40 MeV alpha-particles. The scattered particles were momentum analyzed in a QMG\\/2 magnetic spectrometer and recorded in a position sensitive detector. Several high-spin states were observed in the energy range below 1.7 MeV excitation. The previously unknown strongly populated levels at 867 and 1480 keV

  6. High-spin particle states in 153Sm studied with the (alpha, 3He) reaction

    Microsoft Academic Search

    J. R. Lien; G. Løvhøiden; J. Rekstad; A. Henriques; C. Gaarde; J. S. Larsen; S. Y. van der Werf

    1984-01-01

    High-spin states have been located in 153Sm by means of the (alpha, 3He) reaction with 40 MeV alpha-particles. The scattered particles were momentum-analysed in a QMG\\/2 magnetic spectrometer and recorded in a position-sensitive detector. Several high-spin states were observed below 2 MeV of excitation. Strongly populated levels at 698, 1118 and 1708 keV can most likely be interpreted as 13\\/2+

  7. Relative determination of W-values for alpha particles in tissue-equivalent and other gases

    Microsoft Academic Search

    G L Krieger; J W Baum; M N Varma; J L Beach

    1979-01-01

    W (the average energy to form an ion pair) for 5.4 MeV 241Am alpha particles in a Rossi-type tissue-equivalent (TE) gas, argon and methane was determined to an accuracy better than 0.2% using a new automated data handling system. A vibrating reed electrometer and current digitiser were used to measure the current produced by completely stopping the alpha particles in

  8. Energy dependence of the differential W-value of alpha particles in tissue-equivalent gas

    Microsoft Academic Search

    J. Booz; Th Smit; A. Waker

    1972-01-01

    The linear ion density of alpha -particles of energies 0.27 to 5.3 MeV was measured in tissue-equivalent gas. The results were compared with experimental and theoretical mass stopping powers in order to evaluate the differential W-value of alpha -particles, walpha . Above 1.6 MeV walpha was within 3% agreement with Winfinity , the constant W-value of electrons. For low energies

  9. Behavior of low-energy protons and alpha particles during a disturbed time period

    NASA Technical Reports Server (NTRS)

    Ipavich, F. M.; Gloeckler, G.; Fan, C. Y.; Hovestadt, D.

    1976-01-01

    The paper presents observations of 130- to 1200-keV protons and 40- to 420-keV/nucleon alpha particles made on the earth-orbiting spacecraft Imp 8 and Imp 7 during an active solar period in September 1974, concentrating, in particular, on an energetic storm particle (ESP) event observed in association with an interplanetary shock wave on September 21. It is found that the observed variations in the proton-to-alpha particle ratios and spectral indices can be explained either by 'pileup' or by acceleration models of ESP events. Several instances of local acceleration of particles in the near-earth environment are also discussed.

  10. On resonant excitations of high-n magnetohydrodynamic modes by energetic/alpha particles in tokamaks

    SciTech Connect

    Chen, Liu

    1989-03-01

    Analytical theories for the excitations in tokamaks of magnetohydrodynamic (MHD) modes with large toroidal mode numbers (n>>1) are presented. Specifically, only instability mechanisms due to resonances with energetic ions/alpha particles are considered. It is noted that, while trapped energetic particles contribute to the ideal region, circulating energetic particles contribute mainly to the singular layer dynamics. A unified dispersion relation manifesting both fishbone-like modes and beam transit-resonance modes is then driven. Finally, we also analyze the stability property of toroidicity-induced shear Alfven waves excited via transit resonances with alpha particles in ignited tokamaks. 11 refs.

  11. Fluctuations in recoil numbers

    NASA Astrophysics Data System (ADS)

    Winterbon, K. B.

    The variance of the number of high-energy recoils produced in a cascade is calculated in the power-cross-section approximation. These' recoils have initial energy greater than some specified threshold value, which in turn is greater than a displacement energy. Displacement energy is neglected in this calculation. This distribution of high-energy-recoil number is wider than the Kinchin-Pease distribution but narrower than a Poisson distribution: the variance is (asymptotically) proportional to the number of recoils for all three, and the proportionality constant for the recoil number is greater than the Kinchin-Pease constant but less than unity. Both the asymptotic value of the variance and the energy dependence are obtained. These quantities should be of interest in the study of recoil implantation.

  12. Bose-Einstein condensation of {alpha} particles and Airy structure in nuclear rainbow scattering

    SciTech Connect

    Ohkubo, S. [Department of Applied Science and Environment, Kochi Women's University, Kochi 780-8515 (Japan); Hirabayashi, Y. [Information Initiative Center, Hokkaido University, Sapporo 060-0810 (Japan)

    2004-10-01

    It is shown that the dilute density distribution of {alpha} particles in nuclei can be observed in the Airy structure in nuclear rainbow scattering. We have analyzed {alpha}+{sup 12}C rainbow scattering to the 0{sub 2}{sup +} (7.65 MeV) state of {sup 12}C in a coupled-channel method with the precise wave functions for {sup 12}C. It is found that the enhanced Airy oscillations in the experimental angular distributions for the 0{sub 2}{sup +} state is caused by the dilute density distribution of this state in agreement for the idea of Bose-Einstein condensation of the three alpha particles.

  13. Simulation of {alpha}-particle redistribution due to sawteeth on TFTR

    SciTech Connect

    Yi Zhao; White, R.B.

    1996-12-31

    In recent Deuterium-Tritium experiments on the Tokamak Fusion Test Reactor (TFTR), both the Pellet Charge Exchange (PCX) and the alpha Charge Exchange Recombination Spectroscopy ({alpha}-CHERS) diagnostics indicate that sawtooth oscillations can cause significant broadening of the fusion alpha radial density profile. The authors investigate this sawtooth mixing phenomenon by applying a Hamiltonian guiding center approach. A model of time evolution of the Kadomtsev-type sawtooth is constructed. The presence of more than one mode in the nonlinear stage of the sawtooth crash is necessary to cause significant broadening of the alpha density profile. Use of numerical equilibria allows us to perform detailed comparisons with TFTR experimental data. The results are in reasonable agreement with {alpha}-CHERS and show a broadening of alpha particles similar to that seen in PCX measurements.

  14. Alpha particle transport in the presence of toroidal driftwaves

    NASA Astrophysics Data System (ADS)

    Nishimura, Y.; Huang, B.; Cheng, C. Z.

    2013-10-01

    Transport of fusion born ? particles is investigated in the presence of poloidally mode coupled ballooning type driftwaves. The onset of orbit stochasticity is understood as an overlapping of electric islands produced by the driftwaves, whose overlapping threshold is lower for the thermal particles than for the ? particles (high energy particles). For the trapped particles, transport is determined by the particles' sensitive response to the fluctuation at the banana tip where the parallel velocity decreases drastically. Time dependent turbulent signals (finite ?* effects) give rise to the shift of the resonant radial locations, which again is larger for the thermal particles than the high energy particles. The transport process is influenced by the microscopic structure of the islands, which deviates from the Gaussian process. This work is supported by National Science Council of Taiwan, NSC 100-2112-M-006-021-MY3 and NCKU Top University Project.

  15. Absorbed fractions for alpha-particles in tissues of cortical bone

    NASA Astrophysics Data System (ADS)

    Watchman, Christopher J.; Bolch, Wesley E.

    2009-10-01

    Bone-seeking alpha-particle emitting radionuclides are common health physics hazards. Additionally, they are under consideration as an option for therapeutic molecular radiotherapy applications. Current dose models do not account for energy or bone-site dependence as shown by alpha-particle absorbed fractions given in ICRP Publication 30. Energy-dependent, yet bone-site independent, alpha-particle absorbed fractions have been presented by the models of Stabin and Siegel (2003 Health Phys. 85 294-310). In this work, a chord-based computational model of alpha-particle transport in cortical bone has been developed that explicitly accounts for both the bone-site and particle-energy dependence of alpha-particle absorbed fractions in this region of the skeleton. The model accounts for energy deposition to three targets: cortical endosteum, haversian space tissues and cortical bone. Path length distributions for cortical bone given in Beddoe (1977 Phys. Med. Biol. 22 298-308) provided additional transport regions in the absorbed fraction calculation. Significant variations in absorbed fractions between different skeletal sites were observed. Differences were observed between this model and the absorbed fractions given in ICRP Publication 30, which varied by as much as a factor of 2.1 for a cortical bone surface source irradiating cortical endosteum.

  16. IV. ALPHA-PARTICLE PHYSICS IN BPX D. J. SIGMAR (MIT)

    E-print Network

    al- FUSION TECHNOLOGY VOL. 21 MAY 1992 pha power balance that the coupling parameter qa E [Pa distribution (fa) averaged al- pha pressure including the effect of ur, on the ki- netic equation for fa. (For. Quantitative measurements of 7"" due to al- pha particles require Q 2 2. 1113 #12;Sigmar ALPHA-PARTICLE PHYSICS

  17. Alpha decay of the new isotope 174 Hg

    Microsoft Academic Search

    J. Uusitalo; M. Leino; R. G. Allatt; T. Enqvist; K. Eskola; P. T. Greenless; S. Hurskanen; A. Keenan; H. Kettunen; P. Kuusiniemi; R. D. Page; W. H. Trzaska

    1997-01-01

    Neutron deficient mercury isotopes were produced in the reaction 36Ar + 144Sm using bombarding energies of 180-230 MeV. Fusion products were separated in-flight from the primary beam using a gas-filled recoil separator. An alpha line with the alpha particle energy and half-life of (7069ᆟ) keV and (2.1+1.8т.7) ms, respectively, was assigned to the new mercury isotope 174Hg.

  18. Use of .sup.3 He.sup.30 + ICRF minority heating to simulate alpha particle heating

    DOEpatents

    Post, Jr., Douglass E. (Belle Mead, NJ); Hwang, David Q. (Lawrencevill, NJ); Hovey, Jane (Plainsboro, NJ)

    1986-04-22

    Neutron activation due to high levels of neutron production in a first heated deuterium-tritium plasma is substantially reduced by using Ion Cyclotron Resonance Frequency (ICRF) heating of energetic .sup.3 He.sup.++ ions in a second deuterium-.sup.3 He.sup.++ plasma which exhibit an energy distribution and density similar to that of alpha particles in fusion reactor experiments to simulate fusion alpha particle heating in the first plasma. The majority of the fast .sup.3 He.sup.++ ions and their slowing down spectrum can be studied using either a modulated hydrogen beam source for producing excited states of He.sup.+ in combination with spectrometers or double charge exchange with a high energy neutral lithium beam and charged particle detectors at the plasma edge. The maintenance problems thus associated with neutron activation are substantially reduced permitting energetic alpha particle behavior to be studied in near term large fusion experiments.

  19. Mechanics and multiple-particle tracking microheterogeneity of alpha-actinin-cross-linked actin filament networks.

    PubMed Central

    Tseng, Y; Wirtz, D

    2001-01-01

    Cell morphology is controlled by the actin cytoskeleton organization and mechanical properties, which are regulated by the available contents in actin and actin regulatory proteins. Using rheometry and the recently developed multiple-particle tracking method, we compare the mechanical properties and microheterogeneity of actin filament networks containing the F-actin cross-linking protein alpha-actinin. The elasticity of F-actin/alpha-actinin networks increases with actin concentration more rapidly for a fixed molar ratio of actin to alpha-actinin than in the absence of alpha-actinin, for networks of fixed alpha-actinin concentration and of fixed actin concentration, but more slowly than theoretically predicted for a homogeneous cross-linked semiflexible polymer network. These rheological measurements are complemented by multiple-particle tracking of fluorescent microspheres imbedded in the networks. The distribution of the mean squared displacements of these microspheres becomes progressively more asymmetric and wider for increasing concentration in alpha-actinin and, to a lesser extent, for increasing actin concentration, which suggests that F-actin networks become progressively heterogeneous for increasing protein content. This may explain the slower-than-predicted rise in elasticity of F-actin/alpha-actinin networks. Together these in vitro results suggest that actin and alpha-actinin provides the cell with an unsuspected range of regulatory pathways to modulate its cytoskeleton's micromechanics and local organization in vivo. PMID:11509377

  20. Simple experimental method for alpha particle range determination in lead iodide films.

    PubMed

    Dmitriev, Yuri; Bennett, Paul R; Cirignano, Leonard J; Klugerman, Mikhail; Shah, Kanai S

    2007-05-01

    An experimental method for determining the range of alpha particles in films based on I-V(s) analysis has been suggested. The range of 5.5 MeV alpha particles in PbI(2) films determined by this technique is 30+/-5 microm, and this value is in agreement with the value calculated by SRIM (the stopping and range of ions in matter), r=24 microm in PbI(2). More than 100 I-V(s) of PbI(2) films with different thicknesses and quality have been analyzed, and the influence of alpha particle radiation on PbI(2) I-V(s) curves has been studied. Developed analytical methods (dependence of current density on electric field and conception of surface defects) were used, and the method limitations are discussed. It was shown that I-V(s) demonstrate the tendency to obey Ohm's law under alpha radiation. On the other hand, dark conductivity of the lead iodide films shows a typical impure character that can lead to an overestimation of the alpha particles' range in PbI(2) films. After films were exposed to alpha radiation, the dark resistivity and I-V shape of some films improved. Also, a weak decrease of the charge carrier concentration, due to a decrease of the "surface defect" concentration ("surface refining"), was registered after successive measurements of I-V(s). PMID:17552841

  1. Intense alpha-particle emitting crystallites in uranium mill wastes

    USGS Publications Warehouse

    Landa, E.R.; Stieff, L.R.; Germani, M.S.; Tanner, A.B.; Evans, J.R.

    1994-01-01

    Nuclear emulsion microscopy has demonstrated the presence of small, intense ??-particle emitting crystallites in laboratory-produced tailings derived from the sulfuric acid milling of uranium ores. The ??-particle activity is associated with the isotope pair 210Pb 210Po, and the host mineral appears to be PbSO4 occurring as inclusions in gypsum laths. These particles represent potential inhalation hazards at uranium mill tailings disposal areas. ?? 1994.

  2. Maximum gravitational recoil.

    PubMed

    Campanelli, Manuela; Lousto, Carlos O; Zlochower, Yosef; Merritt, David

    2007-06-01

    Recent calculations of gravitational radiation recoil generated during black-hole binary mergers have reopened the possibility that a merged binary can be ejected even from the nucleus of a massive host galaxy. Here we report the first systematic study of gravitational recoil of equal-mass binaries with equal, but counteraligned, spins parallel to the orbital plane. Such an orientation of the spins is expected to maximize the recoil. We find that recoil velocity (which is perpendicular to the orbital plane) varies sinusoidally with the angle that the initial spin directions make with the initial linear momenta of each hole and scales up to a maximum of approximately 4000 km s-1 for maximally rotating holes. Our results show that the amplitude of the recoil velocity can depend sensitively on spin orientations of the black holes prior to merger. PMID:17677894

  3. Quantum dynamics from the Brownian recoil principle

    Microsoft Academic Search

    Piotr Garbaczewski; Jean-Pierre Vigier

    1992-01-01

    We formulate a theory of the Brownian motion for particle ensembles, whose diffusive evolution is entirely generated by the surrounding random environment. By demanding the validity of the momentum conservation law on all conceivable scales adopted for the investigation of individual particle scattering (collisions) on the medium constituents, we are forced to incorporate the environmental recoil effects in the formalism.

  4. Effects of alpha-particles on survival and chromosomal aberrations in human mammary epithelial cells

    NASA Technical Reports Server (NTRS)

    Durante, M.; Grossi, G. F.; Gialanella, G.; Pugliese, M.; Nappo, M.; Yang, T. C.

    1995-01-01

    We have studied the radiation responses of a human mammary epithelial cell line, H184B5 F5-1 M/10. This cell line was derived from primary mammary cells after treatment with chemicals and heavy ions. The F5-1 M/10 cells are immortal, density-inhibited in growth, and non-tumorigenic in athymic nude mice and represent an in vitro model of the human epithelium for radiation studies. Because epithelial cells are the target of alpha-particles emitted from radon daughters, we concentrated our studies on the efficiency of alpha-particles. Confluent cultures of M/10 cells were exposed to accelerated alpha-particles [beam energy incident at the cell monolayer = 3.85 MeV, incident linear energy transfer (LET) in cell = 109 keV/microns] and, for comparison, to 80 kVp x-rays. The following endpoints were studied: (1) survival, (2) chromosome aberrations at the first postirradiation mitosis, and (3) chromosome alterations at later passages following irradiation. The survival curve was exponential for alpha-particles (D0 = 0.73 +/- 0.04 Gy), while a shoulder was observed for x-rays (alpha/beta = 2.9 Gy; D0 = 2.5 Gy, extrapolation number 1.6). The relative biological effectiveness (RBE) of high-LET alpha-particles for human epithelial cell killing was 3.3 at 37% survival. Dose-response curves for the induction of chromosome aberrations were linear for alpha-particles and linearquadratic for x-rays. The RBE for the induction of chromosome aberrations varied with the type of aberration scored and was high (about 5) for chromosome breaks and low (about 2) for chromosome exchanges.(ABSTRACT TRUNCATED AT 250 WORDS).

  5. Destabilization of planar lipid bilayers by. cap alpha. particles from polonium-210

    SciTech Connect

    Nelson, G.A.

    1984-01-01

    A system for measuring the interacton between ..cap alpha.. particles from /sup 210/Polonium and planar lipid bilayers is described. Membrane capacitance and conductance were simultaneously measured with a voltage clamp. A micrometer advance mechanism was used to control the position of a /sup 210/Polonium source with respect to a bowed-out bilayer. Conductance records showed an abrupt failure of the bilayer when the source was approximately 30 microns or less from the bilayer. Comparisons of conductance noise characteristics just prior to membrane breakage and noise characteristics with a source - bilayer separation of 50 microns or greater showed no difference. The range of the ..cap alpha.. particles inferred from observations of membrane failure is consistent with the expected maximum range of approximately 35 microns for ..cap alpha.. particles from the particular gold-covered source in water. The breakage mechanism is not directly peroxide-mediated as experiments with added peroxide alone did not show significant alterations. The breakdown of lipid bilayers by ..cap alpha.. particles may be analogous to the observations in a set of experiments which showed ..cap alpha.. particle destabilization of surfactant films in air. Evidence supports the hypothesis that free radicals generated in the bilayer, as opposed to aqueous solution free radicals, are the most important agent for bilayer destabilization.

  6. Alpha Particles Play a Relatively Minor Role in Magnetized Target Fusion Systems

    SciTech Connect

    Ryutov, D.D. [Lawrence Livermore National Laboratory (United States)

    2002-03-15

    Two problems related to alpha particle physics in magnetized target fusion (MTF) systems are briefly discussed. First, we evaluate the pressure and density of alpha particles under the assumption that they are perfectly confined and have a classical slowing-down distribution. It turns out that because of a comparatively low plasma temperature in MTF systems, the relative pressure and density of alpha particles are more than an order of magnitude less than in fusion reactors based on ITER-type tokamaks. Therefore, one may expect that even in the extreme case of a perfect confinement of alpha particles, their presence will have a much weaker (than in the case of tokamaks) effect on plasma stability and transport. Second, we discuss the kinetics of plasma burn under the opposite extreme assumption that all the alpha particles are instantaneously lost, without leaving any energy in a plasma. It turns out that even in this case, the plasma energy yield in batch-burn systems is only weakly affected by burnout effects.

  7. CR-SA hysteresis phenomenon on the basis of alpha-particle satellite data

    NASA Astrophysics Data System (ADS)

    Dorman, L. I.; Iucci, N.; Parisi, M.; Villoresi, G.

    We analyzed satellite 5-min data on alpha-particle fluxes in energy intervals 60-160 MeV, 160-260 MeV and 330-500 MeV during January 1986 -- May 2000. In the first we excluded periods with great CR increases caused by particle acceleration in solar flare events. Then we determined monthly averaged fluxes as well as 5 months and 11 months smooth averaged data. We corrected these data on drift effects according to the procedure described in Dorman (2004) in dependence of alpha-particle energies. Corrected on drifts alpha-particles fluxes we compare with expected according to convection-diffusion modulation for different values of supposed dimension of the modulation region (measured by time of solar wind propagation from the Sun to the boundary of this region Xo from 1 to 60 av. months; described in Dorman, 2004). By this way we can determine Xomax, at what the correlation coefficient reaches the maximum value. Then it can be determined the dimension of modulation region (with taking into account the influence of nonlinear processes on the solar wind speed in the outer Heliosphere according to Le Roux and Fichtner, 1997), the radial diffusion coefficient and transport path as well as expected alpha-particle intensity out of the modulation region and absolute alpha-particle modulation (relative to the alpha-particle intensity level in the interstellar space). References: Dorman L.I. ``Expected relative role of drift and convection-diffusion mechanisms in global small energy cosmic ray modulation''. Paper, submitted on the Session D1.2 of COSPAR 2004. Le Roux J.A. and H. Fichtner ``The influence of pickup, anomalous, and galactic cosmic ray protons on the structure of the heliospheric shock: a self consistent approach'', Astrophys. J, 477, L115-L118, 1997.

  8. Investigation of thermal and slowing-down alpha particles on JET using charge-exchange spectroscopy

    Microsoft Academic Search

    M. von Hellermann; W. Mandl; H. P. Summers; A. Boileau; R. Hoekstra; F. J. de Heer; J. Frieling

    1991-01-01

    Thermal alpha particles are observed in JET during helium discharges using spectral emission in He II (n=4 to 3) near 4685 AA following charge transfer reactions along the path of the neutral deuterium heating beams. New and reappraised He22\\/H charge transfer cross-sections are presented. The effects of cross-section energy dependence on temperatures, velocities and absolute densities deduced from thermal alpha

  9. Alpha particle condensation in {sup 12}C and nuclear rainbow scattering

    SciTech Connect

    Ohkubo, S. [Department of Applied Science and Environment, Kochi Women's University, Kochi 780-8515 (Japan); Hirabayashi, Y. [Information Initiative Center, Hokkaido University, Sapporo 060-0811 (Japan)

    2008-05-12

    It is shown that the large radius of the Hoyle state of {sup 12}C with a dilute density distribution in an {alpha} particle condensate can be clearly seen in the shift of the rainbow angle (therefore the Airy minimum) to a larger angle in {alpha}+{sup 12}C rainbow scattering at the high energy region and prerainbow oscillations in {sup 3}He+{sup 12}C scattering at the lower energy region.

  10. Track reconstruction and performance of DRIFT directional dark matter detectors using alpha particles

    Microsoft Academic Search

    S. Burgos; J. Forbes; C. Ghag; M. Gold; V. A. Kudryavtsev; T. B. Lawson; D. Loomba; P. Majewski; D. Muna; A. St J. Murphy; G. G. Nicklin; S. M. Paling; A. Petkov; S. J. S. Plank; M. Robinson; N. Sanghi; N. J. T. Smith; D. P. Snowden-Ifft; N. J. C. Spooner; T. J. Sumner; J. Turk; E. Tziaferi; T. Tziaferi

    2008-01-01

    First results are presented from an analysis of data from the DRIFT-IIa and DRIFT-IIb directional dark matter detectors at Boulby Mine in which alpha particle tracks were reconstructed and used to characterise detector performance—an important step towards optimising directional technology. The drift velocity in DRIFT-IIa was 59.3±0.2(stat)±7.5(sys)ms-1 based on an analysis of naturally occurring alpha-emitting background. The drift velocity in

  11. Fire hose instability driven by alpha particles in the solar wind

    NASA Astrophysics Data System (ADS)

    Matteini, Lorenzo; Hellinger, Petr; Schwartz, Steven J.; Landi, Simone

    2015-04-01

    We discuss the dynamics of fire hose parallel instability driven by anisotropic alpha particles in a plasma with typical solar wind composition (n? = 5%ne). We show, for the first time, the liner and nonlinear dynamics of the instability by means of hybrid numeric simulations, highlighting its dependence on the main plasma parameters, including the relative drift between the alphas and the main proton population. Our results confirm that the parallel fire hose instability can be efficiently excited by anisotropic distribution of the less abundant alpha particles, even when the rest of the plasma (electrons and protons) is Maxwellian. Moreover, our finding suggest that the dynamics driven by the alphas can also influence the properties of the protons. In particular the instability is found to significantly affect the evolution of the alpha-proton drift, constraining its final intensity to values smaller than the local Alfvén speed, as observed in the solar wind far from the Sun. When simulations with both species initially anisotropic are performed, we find a coexistence of the fire hose wave activity excited by both ions, leading to final stable configurations which reflect the marginal stability state of each species. As a consequence, when observed in the commonly used (?||,T?/T||) plane, alpha particles and protons are seen to saturate in different regions of the parameter space. This property is in very good agreement with recent solar wind in situ observations and strongly suggests that those instabilities play a role in regulating the anisotropy solar wind ions.

  12. Alpha particles induce apoptosis through the sphingomyelin pathway.

    PubMed

    Seideman, Jonathan H; Stancevic, Branka; Rotolo, Jimmy A; McDevitt, Michael R; Howell, Roger W; Kolesnick, Richard N; Scheinberg, David A

    2011-10-01

    The sphingomyelin pathway involves the enzymatic cleavage of sphingomyelin to produce ceramide, a second messenger that serves as a key mediator in the rapid apoptotic response to various cell stressors. Low-linear energy transfer (LET) ? radiation can initiate this pathway, independent of DNA damage, via the cell membrane. Whether short-ranged, high-LET ? particles, which are of interest as potent environmental carcinogens, radiotherapies and potential components of dirty bombs, can act through this mechanism to signal apoptosis is unknown. Here we show that irradiation of Jurkat cells with ? particles emitted by the ²²?Ac-DOTA-anti-CD3 IgG antibody construct results in dose-dependent apoptosis. This apoptosis was significantly reduced by pretreating cells with cholesterol-depleting nystatin, a reagent known to inhibit ceramide signaling by interfering with membrane raft coalescence and ceramide-rich platform generation. The effects of nystatin on ?-particle-induced apoptosis were related to disruption of the ceramide pathway and not to microdosimetry alterations, because similar results were obtained after external irradiation of the cells with a broad beam of collimated ? particles using a planar ²?¹Am source. External irradiation allowed for more precise control of the dosimetry and geometry of the irradiation, independent of antibody binding or cell internalization kinetics. Mechanistically consistent with these findings, Jurkat cells rapidly increased membrane concentrations of ceramide after external irradiation with an average of five ?-particle traversals per cell. These data indicate that ? particles can activate the sphingomyelin pathway to induce apoptosis. PMID:21631289

  13. Energetic/alpha particle effects on MHD modes and transport

    SciTech Connect

    Cheng, C.Z.; Budny, R. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Chen, L. [Univ. of California, Irvine, CA (United States). Dept. of Physics

    1995-01-01

    A nonvariational kinetic-MHD stability code (NOVA-K) has been employed to study TAE stability in TFRR D-T and DIII-D experiments and to achieve understanding of TAE instability drive and damping mechanism. Reasonably good agreement between theory and experiment has been obtained. In these experiments the dominant damping mechanism is due to both the thermal ion Landau damping and/or the beam ion Landau damping. Based on ITER EDA parameters, the TAE modes are expected to be unstable in normal ITER operations. Energetic particle transport has been studied using a test particle code (ORBIT). Energetic particle loss scales linearly with the TAE mode amplitude and can be large for TFRR and DIII-D for {delta}B{sub r}/B > 10{sup {minus}4} due to large banana orbit. From quasi-linear (ORBIT) and nonlinear kinetic-MHD (MH3D-K) simulations the saturation of TAE modes is due to nonlinear wave particle trapping and energetic particle profile modification in both radial and energy space. Finally, a convective bucket transport mechanism by MHD waves with time-dependent frequency is presented. Based on the energy-selective characteristics of the bucket transport mechanism, undesirable particles such as helium ash can be removed from the plasma core efficiently.

  14. High resolution alpha particle detectors based on 4H-SiC epitaxial layer

    NASA Astrophysics Data System (ADS)

    Zat'ko, B.; Dubecký, F.; Šagátová, A.; Sedla?ová, K.; Ry?, L.

    2015-04-01

    We fabricated and characterized 4H-SiC Schottky diodes as a spectrometric detector of alpha particles. A thin blocking contact of Ni/Au (15 nm) was used to minimize the influence on alpha particles energy. Current-voltage characteristics of the detector were measured and a low current density below 0.3 nAcm?2 was observed at room temperature. 239Pu241Am244Cm was used as a source of alpha particles within the energy range between 5.1 MeV and 5.8 MeV for detector testing. The charge collection efficiency close to 100 % at reverse bias exceeding 50 V was determined. The best spectrometric performance shows a pulse height spectrum at a reverse bias of 200 V giving an energy resolution of 0.25 % in the full width and half maximum for 5.486 MeV of 241Am.

  15. A study of the effects of MeV alpha particles in PE and PVDC

    SciTech Connect

    Evelyn, A.L.; Ila, D.; Zimmerman, R.L.; Bhat, K. [Center for Irradiation of Materials, Departments of Physics and Chemistry, Alabama AM University, P.O. Box 1447, Normal, Alabama 35762-1447 (United States); Poker, D.B.; Hensley, D.K. [Solid State Division, Oak Ridge National Laboratory, P.O. Box 2008, MS 6048, Oak Ridge, Tennessee 37831 (United States)

    1997-02-01

    We have mapped and studied the effects of MeV alpha-particle bombardment in polyvinylidene chloride (PVDC) and polyethylene (PE). We used 3.5 and 5.0 MeV alpha-particle incident beams and stacked polymer films to separate the contributing effects of the electronic ({var_epsilon}{sub e}) and nuclear ({var_epsilon}{sub n}) stopping powers. The electrical conductance and change in the chemical structures were measured by direct resistivity measurement, Raman microprobe, RBS and FTIR. The results indicate significant differences in the ({var_epsilon}{sub e}) and ({var_epsilon}{sub n}) effects at higher alpha-particle bombardment fluences. {copyright} {ital 1997 American Institute of Physics.}

  16. Rigidity-independent coronal propagation and escape of solar protons and alpha particles

    NASA Technical Reports Server (NTRS)

    Perron, C.; Domingo, V.; Reinhard, R.; Wenzel, K.-P.

    1978-01-01

    In a study of rigidity-independent coronal propagation processes, data on the azimuthal variation of the solar proton/alpha-particle ratio were obtained. Sources for the data included a statistical analysis of events observed by Heos-2, a comparative study of events recorded by both Heos-2 and Pioneer-10 and -11, and a multiday survey of individual events observed by Heos-2 and Pioneer-10. The statistical investigation of Heos-2 events reveals an increase of the lower value of the proton/alpha-particle ratio away from the well-connected region. The data from one or two spacecraft connected at different heliolongitudes indicates no azimuthal dependence of the proton/alpha-particle ratio. All the data appear to suggest rigidity-independent propagation or escape processes.

  17. Investigation of alpha particle induced single-event upsets in charge-coupled devices

    NASA Astrophysics Data System (ADS)

    Pepper, Gary T.; Fechete, Andrew

    1991-12-01

    The mechanisms for generation of single-event upsets (SEUs) in a linear charge coupled device (CCD) were studied through irradiation with monoenergetic 5.48 MeV alpha particles from a very low flux Am source. Spatial correlation (cluster analysis) of soft errors due to single alpha particle hits was demonstrated to be a necessary prerequisite for quantitative analysis of different SEU error-generating phenomena. The Texas Instruments TC-103 virtual phase CCD used in this study is shown to be sensitive to alpha particles not only in the vicinity of photosites as expected, but also in the transport CCDs. This latter effect may have adverse consequences for applications employing CCDs as position-sensitive ionizing radiation detectors. The techniques developed in this work for the analysis of one dimensional arrays is readily extensible to two dimensional CCD arrays.

  18. Quantum dynamics from the Brownian recoil principle

    NASA Astrophysics Data System (ADS)

    Garbaczewski, Piotr; Vigier, Jean-Pierre

    1992-10-01

    We formulate a theory of the Brownian motion for particle ensembles, whose diffusive evolution is entirely generated by the surrounding random environment. By demanding the validity of the momentum conservation law on all conceivable scales adopted for the investigation of individual particle scattering (collisions) on the medium constituents, we are forced to incorporate the environmental recoil effects in the formalism. The Brownian recoil principle elevates the individually negligible phenomena to the momentum conservation law on the ensemble average. The resultant dynamics of the statistical ensemble is governed by the Schrödinger equation, once the diffusion constant D is identified with ?/2m.

  19. Prediction of Lung Cells Oncogenic Transformation for Induced Radon Progeny Alpha Particles Using Sugarscape Cellular Automata

    PubMed Central

    Baradaran, Samaneh; Maleknasr, Niaz; Setayeshi, Saeed; Akbari, Mohammad Esmaeil

    2014-01-01

    Background Alpha particle irradiation from radon progeny is one of the major natural sources of effective dose in the public population. Oncogenic transformation is a biological effectiveness of radon progeny alpha particle hits. The biological effects which has caused by exposure to radon, were the main result of a complex series of physical, chemical, biological and physiological interactions. The cellular and molecular mechanisms for radon-induced carcinogenesis have not been clear yet. Methods Various biological models, including cultured cells and animals, have been found useful for studying the carcinogenesis effects of radon progeny alpha particles. In this paper, sugars cape cellular automata have been presented for computational study of complex biological effect of radon progeny alpha particles in lung bronchial airways. The model has included mechanism of DNA damage, which has been induced alpha particles hits, and then formation of transformation in the lung cells. Biomarkers were an objective measure or evaluation of normal or abnormal biological processes. In the model, the metabolism rate of infected cell has been induced alpha particles traversals, as a biomarker, has been followed to reach oncogenic transformation. Results The model results have successfully validated in comparison with “in vitro oncogenic transformation data” for C3H 10T1/2 cells. This model has provided an opportunity to study the cellular and molecular changes, at the various stages in radiation carcinogenesis, involving human cells. Conclusion It has become well known that simulation could be used to investigate complex biomedical systems, in situations where traditional methodologies were difficult or too costly to employ. PMID:25250147

  20. Enhanced retention of the alpha-particle-emitting daughters of Actinium-225 by liposome carriers.

    PubMed

    Sofou, Stavroula; Kappel, Barry J; Jaggi, Jaspreet S; McDevitt, Michael R; Scheinberg, David A; Sgouros, George

    2007-01-01

    Targeted alpha-particle emitters hold great promise as therapeutics for micrometastatic disease. Because of their high energy deposition and short range, tumor targeted alpha-particles can result in high cancer-cell killing with minimal normal-tissue irradiation. Actinium-225 is a potential generator for alpha-particle therapy: it decays with a 10-day half-life and generates three alpha-particle-emitting daughters. Retention of (225)Ac daughters at the target increases efficacy; escape and distribution throughout the body increases toxicity. During circulation, molecular carriers conjugated to (225)Ac cannot retain any of the daughters. We previously proposed liposomal encapsulation of (225)Ac to retain the daughters, whose retention was shown to be liposome-size dependent. However, daughter retention was lower than expected: 22% of theoretical maximum decreasing to 14%, partially due to the binding of (225)Ac to the phospholipid membrane. In this study, Multivesicular liposomes (MUVELs) composed of different phospholipids were developed to increase daughter retention. MUVELs are large liposomes with entrapped smaller lipid-vesicles containing (225)Ac. PEGylated MUVELs stably retained over time 98% of encapsulated (225)Ac. Retention of (213)Bi, the last daughter, was 31% of the theoretical maximum retention of (213)Bi for the liposome sizes studied. MUVELs were conjugated to an anti-HER2/neu antibody (immunolabeled MUVELs) and were evaluated in vitro with SKOV3-NMP2 ovarian cancer cells, exhibiting significant cellular internalization (83%). This work demonstrates that immunolabeled MUVELs might be able to deliver higher fractions of generated alpha-particles per targeted (225)Ac compared to the relative fractions of alpha-particles delivered by (225)Ac-labeled molecular carriers. PMID:17935286

  1. Annealing effect of the 6H-SiC semiconductor detector for alpha particles

    Microsoft Academic Search

    J. H. HA; S. M. Kang; S. H. Park; H. S. Kim; Y. H. Cho; J. H. Lee; N. H. Lee; J. B. Kim; Y. K. Kim

    2008-01-01

    Alpha-particle detectors based on 6H-SiC semiconductor were fabricated and their electrical and radiation performances were measured. Detector structure was Au\\/Ni\\/6H-SiC\\/Ni\\/Au multi-layer structure. The current–voltage characteristics of the SiC detectors were measured and the radiation response was evaluated by 238Pu with 5.5MeV alpha particles at room temperature in air. The 6H-SiC detectors were annealed by a rapid temperature annealing (RTA) device

  2. Alpha Particles Induce Apoptosis through the Sphingomyelin Pathway

    PubMed Central

    Seideman, Jonathan H.; Stancevic, Branka; Rotolo, Jimmy A.; McDevitt, Michael R.; Howell, Roger W.; Kolesnick, Richard N.; Scheinberg, David A.

    2011-01-01

    The sphingomyelin pathway involves the enzymatic cleavage of sphingomyelin to produce ceramide, a second messenger that serves as a key mediator in the rapid apoptotic response to various cell stressors. Low-linear energy transfer (LET) ? radiation can initiate this pathway, independent of DNA damage, via the cell membrane. Whether short-ranged, high-LET a particles, which are of interest as potent environmental carcinogens, radiotherapies and potential components of dirty bombs, can act through this mechanism to signal apoptosis is unknown. Here we show that irradiation of Jurkat cells with a particles emitted by the 225Ac-DOTA-anti-CD3 IgG antibody construct results in dose-dependent apoptosis. This apoptosis was significantly reduced by pretreating cells with cholesterol-depleting nystatin, a reagent known to inhibit ceramide signaling by interfering with membrane raft coalescence and ceramide-rich platform generation. The effects of nystatin on ?-particle-induced apoptosis were related to disruption of the ceramide pathway and not to microdosimetry alterations, because similar results were obtained after external irradiation of the cells with a broad beam of collimated a particles using a planar 241Am source. External irradiation allowed for more precise control of the dosimetry and geometry of the irradiation, independent of antibody binding or cell internalization kinetics. Mechanistically consistent with these findings, Jurkat cells rapidly increased membrane concentrations of ceramide after external irradiation with an average of five ?-particle traversals per cell. These data indicate that a particles can activate the sphingomyelin pathway to induce apoptosis. PMID:21631289

  3. Theory of energetic/alpha particle effects on magnetohydrodynamic modes in tokamaks

    SciTech Connect

    Chen, L.; White, R.B.; Rewoldt, G.; Colestock, P.; Rutherford, P.H.; Chen, Y.P.; Ke, F.J.; Tsai, S.T.; Bussac, M.N.

    1989-01-01

    The presence of energetic particles is shown to qualitatively modify the stability properties of ideal as well as resistive magnetohydrodynamic (MHD) modes in tokamaks. Specifically, we demonstrate that, consistent with highpower ICRF heating experiments in JET, high energy trapped particles can effectively stabilize the sawtooth mode, providing a possible route to stable high current tokamak operation. An alternative stabilization scheme employing barely circulating energetic particles is also proposed. Finally, we present analytical and numerical studies on the excitations of high-n MHD modes via transit resonances with circulating alpha particles. 14 refs., 3 figs.

  4. Gene expression profile of human lymphocytes exposed to (211)At alpha particles.

    PubMed

    Turtoi, A; Brown, I; Schläger, M; Schneeweiss, F H A

    2010-08-01

    In this study, the Whole Human Genome 44K DNA microarray assay was used for the first time to obtain gene expression profiles in human peripheral blood lymphocytes 2 h after exposure (in suspension) to 6.78 MeV mean energy alpha particles from extracellular (211)At. Lymphocytes were exposed to fluences of 0.3-9.6 x 10(6) alpha particles/cm(2) [corresponding to mean absorbed alpha-particle doses (D(alpha)) of 0.05-1.60 Gy] over 30 min. Significantly modulated expression was identified in 338 early-response genes. Up-regulated expression was evident in 183 early-response genes, while the remaining 155 were down-regulated. Over half of the up-regulated genes and 40% of the down-regulated genes had a known biological process related primarily to cell growth and maintenance and cell communication. Genes associated with cell death were found only in the up-regulated genes and those with development only in the down-regulated genes. Eight selected early-response genes that displayed a sustained up- or down-regulation (CD36, HSPA2, MS4A6A, NFIL3, IL1F9, IRX5, RASL11B and SULT1B1) were further validated in alpha-particle-irradiated lymphocytes of two human individuals using the TaqMan(R) RT-qPCR technique. The results confirmed the observed microarray gene expression patterns. The expression modulation profiles of IL1F9, IRX5, RASL11B and SULT1B1 genes demonstrated similar trends in the two individuals studied. However, no significant linear correlation between increasing relative gene expression and the alpha-particle dose was evident. The results suggest the possibility that a panel of genes that react to alpha-particle radiation does exist and that they merit further study in a greater number of individuals to determine their possible value regarding alpha-particle biodosimetry. PMID:20681779

  5. Nuclear reactions induced by high-energy alpha particles

    NASA Technical Reports Server (NTRS)

    Shen, B. S. P.

    1974-01-01

    Experimental and theoretical studies of nuclear reactions induced by high energy protons and heavier ions are included. Fundamental data needed in the shielding, dosimetry, and radiobiology of high energy particles produced by accelerators were generated, along with data on cosmic ray interaction with matter. The mechanism of high energy nucleon-nucleus reactions is also examined, especially for light target nuclei of mass number comparable to that of biological tissue.

  6. Cross section balance in the 14N + 159Tb reaction and the origin of fast alpha particles

    NASA Astrophysics Data System (ADS)

    Siemssen, R. H.; Balster, G. J.; Wilschut, H. W.; Bond, P. D.; Crouzen, P. C. N.; Goldhoorn, P. B.; Shukui, Han; Sujkowski, Z.

    1985-10-01

    Exclusive cross sections have been obtained from particle-K X-ray coincidence data measured at 236 MeV for ejectiles ranging from 4He to 15N. Production cross sections for primary fragments and alpha particle multiplicities associated with different channels have been deduced. The major fraction of the alpha particles appears to originate from inelastic (damped) processes in which only light particles with Z ? 2 are emitted.

  7. Distributions of Alpha Particles Escaping to the Wall because of Sawtooth Oscillations in TFTR

    SciTech Connect

    Kolesnichenko, Ya.I.; Lutsenko, V.V.; White, R.B.; Yakovenko, Yu.V., Zweben, S.J.

    1998-11-01

    It has been observed experimentally in deuterium-tritium shots of the Tokamak Fusion Test Reactor (TFTR) that crashes of sawtooth oscillations may result in very inhomogeneous flux of alpha particles to the wall. Namely, measurements with four detectors installed at the wall at 20°, 45°, 60°, and 90° below the midplane of the torus have shown that the alpha flux to the wall is strongly peaked at the 20° and 90° detectors and on the noise level at the 45° detector. To explain this phenomenon, both theoretical analysis and numerical simulation have been carried out. It is concluded that the "crash-induced prompt loss," i.e., the orbital loss of marginally trapped particles arising because of the crash-induced orbit transformation of circulating particles, is responsible for the flux to the 90° and 60° detectors, whereas the crash-induced stochastic diffusion of moderately trapped particles explains the large signal at the 20° detector. The calculated poloidal distributions of the integral alpha flux are in reasonable agreement with experimental data. In addition to the integral flux, the flux of particles with given energy was calculated. The energy spectrum of the escaping particles has also been calculated, which can be used for diagnostics of the crash type.

  8. CURRENT DRIVE BY LOWER HYBRID WAVES IN THE PRESENCE OF ENERGETIC ALPHA PARTICLES

    E-print Network

    energetic reactor plasma and, if they do, the wave power may be absorbed by alpha particles rather than not penetrate into the centre of the more energetic reactor plasma, and, second, if they do, as pointed out, reactor plasma, because there are sufficient hot electrons at a distance from the plasma centre

  9. Boron compounds as a dominant source of alpha particles in semiconductor devices

    Microsoft Academic Search

    Robert Baumann; Tim Hossain; Shinya Murata; Hideki Kitagawa

    1995-01-01

    The interaction of cosmic ray neutrons and boron is demonstrated as the dominant source of alpha particles and other radiations in electronic devices utilizing borophosphosilicate glass (BPSG). A simple process modification is proposed to significantly reduce this intense source of ionizing radiation without compromising the reflow and passivation properties of BPSG.

  10. RADON AND PROGENY ALPHA-PARTICLE ENERGY ANALYSIS USING NUCLEAR TRACK METHODOLOGY

    SciTech Connect

    Espinosa Garcia, Guillermo [ORNL; Golzarri y Moreno, Dr. Jose Ignacio [Instituto de Fisica, Mexico; Bogard, James S [ORNL

    2008-01-01

    A preliminary procedure for alpha energy analysis of radon and progeny using Nuclear Track Methodology (NTM) is described in this paper. The method is based on the relationship between alpha-particle energies deposited in polycarbonate material (CR-39) and the track size developed after a well-established chemical etching process. Track geometry, defined by parameters such as major or minor diameters, track area and overall track length, is shown to correlate with alpha-particle energy over the range 6.00 MeV (218Po) to 7.69 MeV (214Po). Track features are measured and the data analyzed automatically using a digital imaging system and commercial PC software. Examination of particle track diameters in CR-39 exposed to environmental radon reveals a multi-modal distribution. Locations of the maxima in this distribution are highly correlated with alpha particle energies of radon daughters, and the distributions are sufficiently resolved to identify the radioisotopes. This method can be useful for estimating the radiation dose from indoor exposure to radon and its progeny.

  11. PPPL-3164 -Preprint Date: January 1996, UC-420 Alpha Particle Losses from Tokamak Fusion Test Reactor

    E-print Network

    Reactor Deuterium-Tritium Plasmas D. S. Darrow, S. J. Zweben, S. Batha*, R. V. Budny, C. E. Bush, Z. Chang. S. Medley, M. Murakami, M. Petrov¶, C. K. Phillips, M. H. Redi, E. Ruskov§, D. A. Spong, E. J on tokamak reactor viability, the loss of deuterium-tritium alpha particles from the Tokamak Fusion Test

  12. alpha-particle knock-on signature in the neutron emission of DT plasmas

    Microsoft Academic Search

    L. Ballabio; G. Gorini; J. Käautllne

    1997-01-01

    The fast alpha-particle kinetic effects in fusion plasmas of deuterium and tritium are studied in the perspective that they can give rise to minority populations of fast fuel ions. The resulting modification of the neutron emission spectrum is computed for a plasma in the state of steady thermonuclear burn of conditions similar to those envisaged for the planned ITER tokamak.

  13. Depleted uranium-catalyzed oxidative DNA damage: absence of significant alpha particle decay

    Microsoft Academic Search

    Alexandra C. Miller; Michael Stewart; Kia Brooks; Lin Shi; Natalie Page

    2002-01-01

    Depleted uranium (DU) is a dense heavy metal used primarily in military applications. Published data from our laboratory have demonstrated that DU exposure in vitro to immortalized human osteoblast cells (HOS) is both neoplastically transforming and genotoxic. DU possesses both a radiological (alpha particle) and a chemical (metal) component. Since DU has a low-specific activity in comparison to natural uranium,

  14. The new Athena alpha particle X-ray spectrometer for the Mars Exploration Rovers

    Microsoft Academic Search

    R. Rieder; R. Gellert; J. Brückner; G. Klingelhöfer; G. Dreibus; A. Yen; S. W. Squyres

    2003-01-01

    The new alpha particle X-ray spectrometer (APXS) is part of the Athena payload of the two Mars Exploration Rovers (MER). The APXS sensor head is attached to the turret of the instrument deployment device (IDD) of the rover. The APXS is a very light-weight instrument for determining the major and minor elemental composition of Martian soils, rocks, and other geological

  15. Differential Flow Between Solar Wind Protons and Alpha Particles: First WIND Observations

    E-print Network

    Richardson, John

    made using the SWE Faraday cup detectors on the WIND p spacecraft are reported. Some overall trends solar wind. e e SWE includes two Faraday cup detectors for measuring th nergy-per-charge spectrum of solar wind protons and alpha - u particles [Ogilvie et al., 1995]. The Faraday cups provide meas rements

  16. Environmental Radioactivity 60 (2002) 293305 Absorbed dose delivered by alpha particles

    E-print Network

    Yu, K.N.

    2002-01-01

    fraction of alpha particles in sensitive cells of the tracheobronchial tree obtained by NRC and ICRP are in good agreement with those obtained previously by NRC and ICRP66. Using the semi-analytical method by NRC and ICRP, respectively, have been satisfactorily reproduced. Using the tissue stopping power

  17. Low temperature alpha particle irradiation of a STAR1000 CMOS APS

    Microsoft Academic Search

    G. R. Hopkinson; A. Mohammadzadeh

    2007-01-01

    A STAR1000 CMOS active pixel sensor was irradiated with alpha particles at -130degC and dark current measurements were made at temperatures up to 25degC. Approximately 90% of dark current spikes were seen to anneal near room temperature. This implies that room temperature irradiations will not give a good estimate of on-orbit effects for cooled applications.

  18. Low Temperature Alpha Particle Irradiation of a STAR1000 CMOS APS

    Microsoft Academic Search

    G. R. Hopkinson; A. Mohammadzadeh

    2008-01-01

    A STAR1000 CMOS active pixel sensor was irradiated with alpha particles at -130deg C and dark current measurements were made at temperatures up to 25degC. Approximately 90% of dark current spikes were seen to anneal near room temperature. This implies that room temperature irradiations will not give a good estimate of on-orbit effects for cooled applications.

  19. BJT detector with FPGA-based read-out for alpha particle monitoring

    Microsoft Academic Search

    V. Tyzhnevyi; G.-F. Dalla Betta; L. Rovati; G. Verzellesi; N. Zorzi

    2011-01-01

    In this work we introduce a new prototype of readout electronics (ALPHADET), which was designed for an alpha-particle detection system based on a bipolar junction transistor (BJT) detector. The system uses an FPGA, which provides many advantages at the stage of prototyping and testing the detector. The main design and electrical features of the board are discussed in this paper,

  20. Anomalous energy loss distributions of alpha particles in heavily implanted thin aluminium films

    Microsoft Academic Search

    K. M. Barfoot; S. E. Donnelly; R. Werz; P. Rietveld

    1982-01-01

    Anomalous energy loss distributions of Gd alpha particles have been observed in heavily implanted thin aluminium films. It is surmised that thin film micro-wrinkling is responsible for the observed effect and that the novel technique of energy loss spectral analysis (ELSA) should be useful in studies of the topography of such films.

  1. Destabilization of low mode number Alfven modes in a tokamak by energetic or alpha particles

    SciTech Connect

    Tsang, K. T.; Sigmar, D. J.; Whitson, J. C.

    1980-12-01

    With the inclusion of finite Larmor radius effects in the shear Alfven eigenmode equation, the continuous Alfven spectrum, which has been extensively discussed in ideal magnetohydrodynamics, is removed. Neutrally stable, discrete radial eigenmodes appear in the absence of sources of free energy and dissipation. Alpha (or energetic) particle toroidal drifts destabilize these modes, provided the particles are faster than the Alfven speed. Although the electron Landu resonance contributes to damping, a stability study of the parametric variation of the energy and the density scale length of the energetic particles shows that modes with low radial mode numbers remain unstable in most cases. Since the alpha particles are concentrated in the center of the plasma, this drift-type instability suggests anomalous helium ash diffusion. Indeed, it is shown that stochasticity of alpha orbits due to the overlapping of radially neighboring Alfven resonances is induced at low amplitudes, e/sub i//sup approx./phi/T/sub i/ greater than or equal to 0.05, implying a diffusion coefficient D/sub r//sup ..cap alpha../ greater than or equal to 4.4 x 10/sup 3/cm/sup 2//s.

  2. Fabrication of substrates with curvature for cell cultivation by alpha-particle irradiation and chemical etching of PADC films

    E-print Network

    Yu, K.N.

    . As an application, the present work studied mechanosensing of substrate curvature by epithelial cells (HeLa cellsFabrication of substrates with curvature for cell cultivation by alpha-particle irradiation online 16 February 2012 Keywords: Microfabrication Cell-culture substrates Alpha particles PADC Substrate

  3. Alpha Particle-Driven Toroidal Alfv en Eigenmodes in Tokamak Fusion Test Reactor Deuterium-Tritium Plasmas: Theory and

    E-print Network

    Alpha Particle-Driven Toroidal Alfv en Eigenmodes in Tokamak Fusion Test Reactor Deuterium-Tritium 26, 11 1984 Deuterium- Tritium plasmas are analyzed using the NOVA-K code C. Z. Cheng, Phys. Reports Deuterium-Tritium DT plasma, the fusion product alpha particles are born with an energy of 3:5 Me

  4. Studying effects of Magnolol on alpha-particle induced bystander effects using PADC-film based dishes

    E-print Network

    Yu, K.N.

    Studying effects of Magnolol on alpha-particle induced bystander effects using PADC-film based May 2009 Accepted 17 October 2009 Keywords: Bystander effect Alpha-particle CHO cells Magnolol PADC irradiated directly by ionizing radiation. In the present paper, the effects of Magnolol, an extract from

  5. Alpha particle induced DNA damage and repair in normal cultured thyrocytes of different proliferation status.

    PubMed

    Lyckesvärd, Madeleine Nordén; Delle, Ulla; Kahu, Helena; Lindegren, Sture; Jensen, Holger; Bäck, Tom; Swanpalmer, John; Elmroth, Kecke

    2014-07-01

    Childhood exposure to ionizing radiation increases the risk of developing thyroid cancer later in life and this is suggested to be due to higher proliferation of the young thyroid. The interest of using high-LET alpha particles from Astatine-211 ((211)At), concentrated in the thyroid by the same mechanism as (131)I [1], in cancer treatment has increased during recent years because of its high efficiency in inducing biological damage and beneficial dose distribution when compared to low-LET radiation. Most knowledge of the DNA damage response in thyroid is from studies using low-LET irradiation and much less is known of high-LET irradiation. In this paper we investigated the DNA damage response and biological consequences to photons from Cobolt-60 ((60)Co) and alpha particles from (211)At in normal primary thyrocytes of different cell cycle status. For both radiation qualities the intensity levels of ?H2AX decreased during the first 24h in both cycling and stationary cultures and complete repair was seen in all cultures but cycling cells exposed to (211)At. Compared to stationary cells alpha particles were more harmful for cycling cultures, an effect also seen at the pChk2 levels. Increasing ratios of micronuclei per cell nuclei were seen up to 1Gy (211)At. We found that primary thyrocytes were much more sensitive to alpha particle exposure compared with low-LET photons. Calculations of the relative biological effectiveness yielded higher RBE for cycling cells compared with stationary cultures at a modest level of damage, clearly demonstrating that cell cycle status influences the relative effectiveness of alpha particles. PMID:24769180

  6. Lung cancer risk from exposure to alpha particles and inhalation of other pollutants in rats

    SciTech Connect

    Burns, F.J.

    1990-01-01

    The goal of these experiments is to establish a quantitative correlation between early DNA damage and cancer incidence in a way that would be helpful for assessing the carcinogenic risk of radon alone or in combination with specific indoor pollutants. Rat tracheal epithelium has been exposed in vivo to {sup 210}Po alpha particles in the presence and absence of NO{sub 2} or cigarette smoke. The major accomplishments so far are: the design and implementation of a tracheal implant to simulate radon alpha particle exposure, the measurement of DNA breaks in a small 7.0 mm segment of the trachea exposed to external x-irradiation, the measurement of the rate of repair of the x-ray induced tracheal DNA strand breaks, the measurement of DNA strand breaks following inhalation of cigarette smoke or NO{sub 2}, the measurement of tracheal DNA stand breaks following exposure to high doses {sup 210}Po alpha particle radiation, the assessment of the amount of mucous in the goblet cells and in the underlying mucous glands. So far we have been unable to detect DNA strand breaks in the tracheal epithelium as a result of exposure to NO{sub 2} cigarette smoke or {sup 210}Po alpha particles. We have developed a simple artificial' trachea consisting of rat tracheal epithelial cells growing on a basement membrane coated millipore filter. Experiments are proposed to utilize these artificial tracheas to eliminate the potential interference of increased mucous secretion and/or inflammation that can significantly affect the radiation dose from the alpha particles. 61 refs., 17 figs.

  7. Production of actinium-225 for alpha particle mediated radioimmunotherapy.

    PubMed

    Boll, Rose A; Malkemus, Dairin; Mirzadeh, Saed

    2005-05-01

    The initial clinical trials for treatment of acute myeloid leukemia have demonstrated the effectiveness of the alpha emitter (213)Bi in killing cancer cells. Bismuth-213 is obtained from a radionuclide generator system from decay of 10-days (225)Ac parent. Recent pre-clinical studies have also shown the potential application of both (213)Bi, and the (225)Ac parent radionuclide in a variety of cancer systems and targeted radiotherapy. This paper describes our five years of experience in production of (225)Ac in partial support of the on-going clinical trials. A four-step chemical process, consisting of both anion and cation exchange chromatography, is utilized for routine separation of carrier-free (225)Ac from a mixture of (228)Th, (229)Th and (232)Th. The separation of Ra and Ac from Th is achieved using the marcoporous anion exchange resin MP1 in 8M HNO(3) media. Two sequential MP1/NO(3) columns provide a separation factor of approximately 10(6) for Ra and Ac from Th. The separation of Ac from Ra is accomplished on a low cross-linking cation exchange resin AG50-X4 using 1.2M HNO(3) as eluant. Two sequential AG50/NO(3) columns provide a separation factor of approximately 10(2) for Ac from Ra. A 60-day processing schedule has been adopted in order to reduce the processing cost and to provide the highest levels of (225)Ac possible. Over an 8-week campaign, a total of approximately 100 mCi of (225)Ac (approximately 80% of the theoretical yield) is shipped in 5-6 batches, with the first batch typically consisting of approximately 50 mCi. After the initial separation and purification of Ac, the Ra pool is re-processed on a bi-weekly schedule or as needed to provide smaller batches of (225)Ac. The averaged radioisotopic purity of the (225)Ac was 99.6 +/- 0.7% with a (225)Ra content of < or =0.6%, and an average (229)Th content of (4(-4)(+5)) x 10(-5)%. PMID:15763472

  8. Variation of the track etch rates of alpha-particle trajectory in PADC

    NASA Astrophysics Data System (ADS)

    Zaki, M. F.; Hegazy, T. M.; Seddik, U.; Morsy, A. A.

    2005-01-01

    The formation of etched tracks in solid-state nuclear track detectors is usually described by assuming an unequivocal correlation of the etch-rate ratio with the energy loss of charged particles. For alpha particles, this assumption could be verified within the scatter of the experimental data. In this article, the dependence of the depth (x) on the track etch rate (V-T) was determined experimentally by track length measurement. It is found that the track etch rate as a function of the depth within the detector follows the Bragg curve. The track etch rate has been found to be described by a generalization of the restricted energy loss, in good approximation along the trajectories of alpha particles.

  9. Map model for nonlinear alpha particle interaction with toroidal Alfven waves

    SciTech Connect

    Berk, H.L.; Breizman, B.N.; Ye, H.

    1992-09-01

    A map model has been developed for studying the nonlinear interaction of alpha particles with the toroidal Alfven eigenmodes. The map is constructed by assuming a linear interaction during a single poloidal transit, which allows the study of the nonlinear interaction over many transits. By using this map, analytic expressions are obtained for the particle nonlinear bounce frequency, and the wave amplitude threshold for the onset of particle orbit stochasticity. The map model can also facilitate self-consistent simulations which incorporate the time variation of the waves.

  10. Alpha-particle capture reactions in inverse kinematics relevant to p-process nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Uji?, P.; Lagoyannis, A.; Mertzimekis, T. J.; de Oliveira Santos, F.; Harissopulos, S.; Demetriou, P.; Perrot, L.; Stodel, Ch.; Saint-Laurent, M.-G.; Kamalou, O.; Lefebvre-Schuhl, A.; Spyrou, A.; Amthor, M. A.; Grevy, S.; Caceres, L.; Koivisto, H.; Laitinen, M.; Uusitalo, J.; Julin, R.

    2011-10-01

    The first feasibility study of an ?-particle capture reaction in inverse kinematics at energies relevant to the p process was performed at the Wien Filter of the LISE spectrometer at GANIL. Hereby, the 4He(78Kr,?)82Sr reaction was investigated using as target an 4He-implanted thin Al foil. The analysis of the data has shown that the determination of (?,?) reaction cross sections at rather low energies around 2 MeV/u in inverse kinematics is indeed feasible regarding the high rejection rate of the primary beam, which in the present work was better than a factor of 109. However, the expected position of the recoils of interest was completely masked by particles of currently unknown origin that could hardly be attributed to scattering of the primary beam. The most probable explanation for the origin of these "pollutants" could be microscopic dust particles of 10 ?m diameter and less, that are extremely difficult to avoid in standard experimental conditions. Hence, the use of a gas-jet target instead of a solid one is compulsory.

  11. Neoclassical Simulations of Fusion Alpha Particles in Pellet Charge Exchange Experiments on the Tokamak Fusion Test Reactor

    SciTech Connect

    Batha, S.H.; Budny, R.V.; Darrow, D.S.; Levinton, F.M.; Redi, M.H.; et al

    1999-02-01

    Neoclassical simulations of alpha particle density profiles in high fusion power plasmas on the Tokamak Fusion Test Reactor (TFTR) [Phys. Plasmas 5 (1998) 1577] are found to be in good agreement with measurements of the alpha distribution function made with a sensitive active neutral particle diagnostic. The calculations are carried out in Hamiltonian magnetic coordinates with a fast, particle-following Monte Carlo code which includes the neoclassical transport processes, a recent first-principles model for stochastic ripple loss and collisional effects. New global loss and confinement domain calculations allow an estimate of the actual alpha particle densities measured with the pellet charge exchange diagnostic.

  12. Electronic Properties of DNA-Based Schottky Barrier Diodes in Response to Alpha Particles.

    PubMed

    Al-Ta'ii, Hassan Maktuff Jaber; Periasamy, Vengadesh; Amin, Yusoff Mohd

    2015-01-01

    Detection of nuclear radiation such as alpha particles has become an important field of research in recent history due to nuclear threats and accidents. In this context; deoxyribonucleic acid (DNA) acting as an organic semiconducting material could be utilized in a metal/semiconductor Schottky junction for detecting alpha particles. In this work we demonstrate for the first time the effect of alpha irradiation on an Al/DNA/p-Si/Al Schottky diode by investigating its current-voltage characteristics. The diodes were exposed for different periods (0-20 min) of irradiation. Various diode parameters such as ideality factor, barrier height, series resistance, Richardson constant and saturation current were then determined using conventional, Cheung and Cheung's and Norde methods. Generally, ideality factor or n values were observed to be greater than unity, which indicates the influence of some other current transport mechanism besides thermionic processes. Results indicated ideality factor variation between 9.97 and 9.57 for irradiation times between the ranges 0 to 20 min. Increase in the series resistance with increase in irradiation time was also observed when calculated using conventional and Cheung and Cheung's methods. These responses demonstrate that changes in the electrical characteristics of the metal-semiconductor-metal diode could be further utilized as sensing elements to detect alpha particles. PMID:26007733

  13. Electronic Properties of DNA-Based Schottky Barrier Diodes in Response to Alpha Particles

    PubMed Central

    Al-Ta’ii, Hassan Maktuff Jaber; Periasamy, Vengadesh; Amin, Yusoff Mohd

    2015-01-01

    Detection of nuclear radiation such as alpha particles has become an important field of research in recent history due to nuclear threats and accidents. In this context; deoxyribonucleic acid (DNA) acting as an organic semiconducting material could be utilized in a metal/semiconductor Schottky junction for detecting alpha particles. In this work we demonstrate for the first time the effect of alpha irradiation on an Al/DNA/p-Si/Al Schottky diode by investigating its current-voltage characteristics. The diodes were exposed for different periods (0–20 min) of irradiation. Various diode parameters such as ideality factor, barrier height, series resistance, Richardson constant and saturation current were then determined using conventional, Cheung and Cheung’s and Norde methods. Generally, ideality factor or n values were observed to be greater than unity, which indicates the influence of some other current transport mechanism besides thermionic processes. Results indicated ideality factor variation between 9.97 and 9.57 for irradiation times between the ranges 0 to 20 min. Increase in the series resistance with increase in irradiation time was also observed when calculated using conventional and Cheung and Cheung’s methods. These responses demonstrate that changes in the electrical characteristics of the metal-semiconductor-metal diode could be further utilized as sensing elements to detect alpha particles. PMID:26007733

  14. Lost alpha-particle diagnostics from a D-T plasma by using nuclear reactions

    SciTech Connect

    Sasao, Mamiko [Organization for Research Initiative and Development, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan); Wada, Motoi [Graduate School of Science and Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan); Isobe, Mitsutaka [National Institute for Fusion Science, Toki Gifu 509-5292 (Japan)

    2014-08-21

    Among various methods proposed for alpha-particles loss measurement, we studied on those by measuring gamma rays of three cases, from (1) nuclear reactions induced by alpha particles, (2) those from short-life-time activities and (3) those from long-life-time activities induced by alpha particles. The time evolution of local alpha flux may possibly be measured by using the {sup 9}Be (a, n) {sup 12}C reaction (1). Using the same system, but with a target set up close to the first wall, activation measurement on site right after turning-off the discharge is possible (2). Nuclear reaction, {sup 25}Mg (a, p) {sup 28}Al, that produce radioisotopes of short lifetime of 2.2 minutes in one of the best candidates. As to the activation to a long lifetime (3), it is predicted that the gamma ray yield from {sup 19}F (a, n) {sup 22}Na reaction is enough for the measurement at the reactor site.

  15. Skeletal dosimetry models for alpha-particles for use in molecular radiotherapy

    NASA Astrophysics Data System (ADS)

    Watchman, Christopher J.

    Molecular radiotherapy is a cancer treatment methodology whereby a radionuclide is combined with a biologically active molecule to preferentially target cancer cells. Alpha-particle emitting radionuclides show significant potential for use in molecular radiotherapy due to the short range of the alpha-particles in tissue and their high rates of energy deposition. Current radiation dosimetry models used to assess alpha emitter dose in the skeleton were developed originally for occupational applications. In medical dosimetry, individual variability in uptake, translocation and other biological factors can result in poor correlation of clinical outcome with marrow dose estimates determined using existing skeletal models. Methods presented in this work were developed in response to the need for dosimetry models which account for these biological and patient-specific factors. Dosimetry models are presented for trabecular bone alpha particle dosimetry as well as a model for cortical bone dosimetry. These radiation transport models are the 3D chord-based infinite spongiosa transport model (3D-CBIST) and the chord-based infinite cortical transport model (CBICT), respectively. Absorbed fraction data for several skeletal tissues for several subjects are presented. Each modeling strategy accounts for biological parameters, such as bone marrow cellularity, not previously incorporated into alpha-particle skeletal dosimetry models used in radiation protection. Using these data a study investigating the variability in alpha-particle absorbed fractions in the human skeleton is also presented. Data is also offered relating skeletal tissue masses in individual bone sites for a range of ages. These data are necessary for dose calculations and have previously only been available as whole body tissue masses. A revised 3D-CBIST model is also presented which allows for changes in endosteum thickness to account for revised target cell location of tissues involved in the radiological induction of bone cancer. In addition, new data are presented on the location of bone-marrow stem cells within the marrow cavities of trabecular bone of the pelvis. All results presented in this work may be applied to occupational exposures, but their greatest utility lies in dose assessments for alpha-emitters in molecular radiotherapy.

  16. Search for {alpha}-states in {sup 13}C via elastic resonant scattering of {alpha} particles on {sup 9}Be

    SciTech Connect

    Lombardo, I.; Campajola, L.; Rosato, E.; Spadaccini, G.; Vigilante, M. [Dipartimento di Scienze Fisiche dell'Universita di Napoli Federico II INFN - Sezione di Napoli, Napoli (Italy)

    2013-07-18

    We will discuss new experimental data concerning the elastic resonant scattering of {alpha}-particles on {sup 9}Be nuclei at bombarding energies from 3.5 MeV up to 9.9 MeV. Several excitation functions have been obtained at different polar angles, mainly in the backward hemisphere in the centre of mass frame. Excitation functions show various anomalies that can be linked to the presence of various excited states in the {sup 13}C compound nucleus. In the literature, some of these states have been proposed to belong to rotational bands built on deformed a-cluster excited state. Unfortunately, up to date the spin-parity assignment of many of these states is doubtful. The set of excitation functions we obtained from the present experiment can contribute to improve spectroscopy of highling excited states of {sup 13}C.

  17. Ionization and scintillation response of high-pressure xenon gas to alpha particles

    NASA Astrophysics Data System (ADS)

    Álvarez, V.; Borges, F. I. G.; Cárcel, S.; Cebrián, S.; Cervera, A.; Conde, C. A. N.; Dafni, T.; Díaz, J.; Egorov, M.; Esteve, R.; Evtoukhovitch, P.; Fernandes, L. M. P.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Gehman, V. M.; Gil, A.; Goldschmidt, A.; Gómez, H.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Hauptman, J.; Hernando Morata, J. A.; Herrera, D. C.; Irastorza, I. G.; Jinete, M. A.; Labarga, L.; Laing, A.; Liubarsky, I.; Lopes, J. A. M.; Lorca, D.; Losada, M.; Luzón, G.; Marí, A.; Martín-Albo, J.; Miller, T.; Moiseenko, A.; Monrabal, F.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Natal da Luz, H.; Navarro, G.; Nebot-Guinot, M.; Nygren, D.; Oliveira, C. A. B.; Palma, R.; Pérez, J.; Pérez Aparicio, J. L.; Renner, J.; Ripoll, L.; Rodríguez, A.; Rodríguez, J.; Santos, F. P.; dos Santos, J. M. F.; Seguí, L.; Serra, L.; Shuman, D.; Simón, A.; Sofka, C.; Sorel, M.; Toledo, J. F.; Tomás, A.; Torrent, J.; Tsamalaidze, Z.; Vázquez, D.; Veloso, J. F. C. A.; Webb, R.; White, J. T.; Yahlali, N.

    2013-05-01

    High-pressure xenon gas is an attractive detection medium for a variety of applications in fundamental and applied physics. In this paper we study the ionization and scintillation detection properties of xenon gas at 10 bar pressure. For this purpose, we use a source of alpha particles in the NEXT-DEMO time projection chamber, the large scale prototype of the NEXT-100 neutrinoless double beta decay experiment, in three different drift electric field configurations. We measure the ionization electron drift velocity and longitudinal diffusion, and compare our results to expectations based on available electron scattering cross sections on pure xenon. In addition, two types of measurements addressing the connection between the ionization and scintillation yields are performed. On the one hand we observe, for the first time in xenon gas, large event-by-event correlated fluctuations between the ionization and scintillation signals, similar to that already observed in liquid xenon. On the other hand, we study the field dependence of the average scintillation and ionization yields. Both types of measurements may shed light on the mechanism of electron-ion recombination in xenon gas for highly-ionizing particles. Finally, by comparing the response of alpha particles and electrons in NEXT-DEMO, we find no evidence for quenching of the primary scintillation light produced by alpha particles in the xenon gas.

  18. Alpha-particle-induced luminescence of rare-earth-doped Y 2O 3 nanophosphors

    NASA Astrophysics Data System (ADS)

    Cress, Cory D.; Redino, Christopher S.; Landi, Brian J.; Raffaelle, Ryne P.

    2008-08-01

    The feasibility of utilizing Y 2O 3:Tb 3+ and Y 2O 3:Eu 3+ as radioluminescent nanophosphors under alpha-particle excitation is investigated. Materials synthesized by the urea homogeneous precipitation method were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The XRD analysis of as-produced precipitates and nanophosphors fired at temperatures ranging from 950 to 1100 °C indicated the presence of highly crystalline cubic Y 2O 3 with crystallite sizes of ˜40 nm. SEM and TEM analysis revealed that particles with average diameters of ˜200 nm and comprised of ˜40 nm grains were obtained. High-resolution radioluminescence and photoluminescence spectra were used to investigate the unwanted radioluminescence saturation effects associated with the high ionization rate of alpha-particles. Additionally, the radioluminescence intensity as a function of rare-earth ion dopant concentration is investigated for these materials under alpha-particle excitation. The prospect for utilizing these materials as intermediate absorbers in indirect-conversion radioisotope batteries is discussed.

  19. Cryogenic microcalorimeter system for ultra-high resolution alpha-particle spectrometry

    SciTech Connect

    Rabin, Michael W [Los Alamos National Laboratory; Hoover, Andrew S [Los Alamos National Laboratory; Bacrania, Mnesh K [Los Alamos National Laboratory; Croce, Mark P [Los Alamos National Laboratory; Hoteling, N J [Los Alamos National Laboratory; Lamont, S P [Los Alamos National Laboratory; Plionis, A A [Los Alamos National Laboratory; Dry, D E [Los Alamos National Laboratory; Ullom, J N [NIST; Bennett, D A [NIST; Horansky, R [NIST; Kotsubo, V [NIST; Cantor, R [STAR CRYOELECTRONICS

    2009-01-01

    Microcalorimeters have been shown to yield unsurpassed energy resolution for alpha spectrometry, up to 1.06 keV FWHM at 5.3 MeV. These detectors use a superconducting transition-edge sensor (TES) to measure the temperature change in an absorber from energy deposited by an interacting alpha particle. Our system has four independent detectors mounted inside a liquid nitrogen/liquid helium cryostat. An adiabatic demagnetization refrigerator (ADR) cools the detector stage to its operating temperature of 80 mK. Temperature regulation with {approx}15 uK peak-to-peak variation is achieved by PID control of the ADR. The detectors are voltage-biased, and the current signal is amplified by a commercial SQUID readout system and digitized for further analysis, This paper will discuss design and operation of our microcalorimeter alpha spectrometer, and will show recent results.

  20. Survival and yields of chromosome aberrations in hamster and human lung cells irradiated by alpha particles

    SciTech Connect

    Simmons, J.A.; Cohn, P.; Min, T. [Univ. of Westminster, London (United Kingdom)

    1996-02-01

    The effects of {alpha}-particle irradiation on hamster and human lung cells have been studied. In both cases two end points were taken, cell death and the induction of chromosome aberrations. The hamster cells were common stock V79 cells; the human ones were freshly derived from fetal material. For both types of cells, the survival curves could be described by straight lines in the conventional exponential plot, with values of D{sub 0} of 0.78 and 0.37 Gy for the hamster and human cells, respectively. The rate of induction of chromosome aberrations could also be described by straight lines with slopes of 0.30 and 0.62 aberration per cell per gray. Thus, for this second end point also, it appears that human cells are twice as sensitive to the effects of {alpha}-particle irradiation as hamster cells. 30 refs., 3 figs., 2 tabs.

  1. Targeted alpha-particle radiotherapy with 211At-labeled monoclonal antibodies.

    PubMed

    Zalutsky, Michael R; Reardon, David A; Pozzi, Oscar R; Vaidyanathan, Ganesan; Bigner, Darell D

    2007-10-01

    An attractive feature of targeted radionuclide therapy is the ability to select radionuclides and targeting vehicles with characteristics that are best suited for a particular clinical application. One combination that has been receiving increasing attention is the use of monoclonal antibodies (mAbs) specifically reactive to receptors and antigens that are expressed in tumor cells to selectively deliver the alpha-particle-emitting radiohalogen astatine-211 (211At) to malignant cell populations. Promising results have been obtained in preclinical models with multiple 211At-labeled mAbs; however, translation of the concept to the clinic has been slow. Impediments to this process include limited radionuclide availability, the need for suitable radiochemistry methods operant at high activity levels and lack of data concerning the toxicity of alpha-particle emitters in humans. Nonetheless, two clinical trials have been initiated to date with 211At-labeled mAbs, and others are planned for the near future. PMID:17921029

  2. Cytotoxic reaction and TNF-alpha response of macrophages to polyurethane particles.

    PubMed

    Ma, Nan; Petit, Alain; Yahia, L'Hocine; Huk, Olga L; Tabrizian, Maryam

    2002-01-01

    Their unique mechanical and biological properties make polyurethanes (PUs) ideal materials for many implantable devices. However, uncertain long-term biostability in the human physiological environment limits their extensive clinical applications. Chronic inflammatory response associated with macrophage activation has been suggested as a prime factor; although the mechanism of macrophage activation in response to biomaterial surfaces and debris is still unknown. The overall objective of this work was to study the response of macrophages to PU materials in vitro by measuring cell viability and activity. The studies were carried out using phagocytozable-size PU particles from three types of commercially-available PUs: Pellethane 2363 80ABA (PL); Tecothane TT2065 (TC65); and Tecothane TT2085 (TC85). These polymers posess the same generic composition but differ in the length of hard and soft segments, as revealed by the FTIR and NMR studies. The results showed that PU particles affected both viability and activity of J774 macrophages. The percentage of mortality ranged from 1 to 15% with 10-100 microg ml(-1) of particles after 24 and 48 h incubation. These three types of particles induced different mortality on the macrophages. Specifically, the mortality with PL particles was 1-4% (p > 0.05), while the mortality with TC85 particles was 2-10% (p < 0.05) and 4-15% with TC65 (p < 0.05). Conversely, these particles also affected cell proliferation. Cell numbers increased by 132 and 167% after 24 and 48 h incubation, respectively, without particles, whereas the cell numbers increased only 46 and 78% with TC65, 66 and 105% with TC85, and 67 and 110% with PL in the presence of 100 microg ml(-1) of particles for the respective incubation times. PU particles also increased TNF-alpha release from macrophage. After having been incubated for 24 h with 100 microg ml(-1) particles of TC65, TC85, and PL, macrophages release TNF-alpha 7.4, 5.2, and 4.1 times more than the control. In conclusion, PU particles had cytotoxic effects on J774 macrophage at high concentrations. The order of macrophage response for three types of particles was TC65 > TC85 > PL. PU particles' effect on macrophage viability and activity depends on the concentration of particles and their chemical composition, especially on the ratio of hard to soft segments. PMID:12102593

  3. Mutagenic effects of a single and an exact number of alpha particles in mammalian cells

    NASA Technical Reports Server (NTRS)

    Hei, T. K.; Wu, L. J.; Liu, S. X.; Vannais, D.; Waldren, C. A.; Randers-Pehrson, G.

    1997-01-01

    One of the main uncertainties in risk estimation for environmental radon exposure using lung cancer data from underground miners is the extrapolation from high- to low-dose exposure where multiple traversal is extremely rare. The biological effects of a single alpha particle are currently unknown. Using the recently available microbeam source at the Radiological Research Accelerator Facility at Columbia University, we examined the frequencies and molecular spectrum of S1- mutants induced in human-hamster hybrid (A(L)) cells by either a single or an exact number of alpha particles. Exponentially growing cells were stained briefly with a nontoxic concentration of Hoechst dye for image analysis, and the location of individual cells was computer-monitored. The nucleus of each cell was irradiated with either 1,2,4, or 8 alpha particles at a linear energy transfer of 90 keV/microm consistent with the energy spectrum of domestic radon exposure. Although single-particle traversal was only slightly cytotoxic to A(L) cells (survival fraction approximately 0.82), it was highly mutagenic, and the induced mutant fraction averaged 110 mutants per 10(5) survivors. In addition, both toxicity and mutant induction were dose-dependent. Multiplex PCR analysis of mutant DNA showed that the proportion of mutants with multilocus deletions increased with the number of particle traversals. These data provide direct evidence that a single a particle traversing a nucleus will have a high probability of resulting in a mutation and highlight the need for radiation protection at low doses.

  4. Determination of the range of alpha particles in histological samples using a proton beam

    Microsoft Academic Search

    M Giacomelli; J Skvar?; R Ili?

    2001-01-01

    The 70?m-thick sliced mouse samples used in boron neutron capture therapy research are normally freeze-dried and permanently mounted on a sticky tape. Such a preparation alters the tissue density and makes it impossible to correctly determine the ranges of the alpha particles from the 10B(n,?)7Li reaction. Proton radiography utilising etched-track detectors can be successfully used for the density determination of

  5. Ionisation cross sections of Cd, Sn, Te, I and Ba for protons and alpha particles

    Microsoft Academic Search

    L. Avaldi; M. Milazzo; G. Trivia; I. V. Mitchell

    1983-01-01

    K-shell X-ray production cross sections of 48Cd, 50Sn, 52Te, 53I and 56Ba have been measured for alpha particles with energies between 2.2 and 2.8 MeV. In addition, production cross sections for 52Te have been measured for protons between 1.6 and 3 MeV. The values have been compared with the earlier experiments and with the theoretical predictions given by four different

  6. Choosing fitting functions to describe peak tails in alpha-particle spectrometry

    Microsoft Academic Search

    C. John Bland

    1998-01-01

    We seek to identify the major differences between two types of peak-fitting programs for alpha-particle spectrometry. One function is the well-known convolution of a Gaussian function with two (usually) left-handed exponential functions. The other function is contained in an analysis program described by Koskelo et al. (Koskelo, M. J., Burnett, W. C. and Cable, P. H. (1996) An advanced analysis

  7. Alpha-Particle-Driven Toroidal Alfvén Eigenmodes in the Tokamak Fusion Test Reactor

    Microsoft Academic Search

    R. Nazikian; G. Y. Fu; S. H. Batha; M. G. Bell; R. E. Bell; R. V. Budny; C. E. Bush; Z. Chang; Y. Chen; C. Z. Cheng; D. S. Darrow; P. C. Efthimion; E. D. Fredrickson; N. N. Gorelenkov; B. Leblanc; F. M. Levinton; R. Majeski; E. Mazzucato; S. S. Medley; H. K. Park; M. P. Petrov; D. A. Spong; J. D. Strachan; E. J. Synakowski; G. Taylor; S. von Goeler; R. B. White; K. L. Wong; S. J. Zweben

    1997-01-01

    Alpha-particle-driven toroidal Alfvén eigenmodes (TAEs) have been observed for the first time in deuterium-tritium (D-T) plasmas on the tokamak fusion test reactor (TFTR). These modes are observed 100-200 ms following the end of neutral beam injection in plasmas with reduced central magnetic shear and elevated central safety factor [q0>1]. Mode activity is localized to the central region of the discharge

  8. GaN as a detector of alpha-particles and neutrons

    Microsoft Academic Search

    A. Y. Polyakov; N. B. Smirnov; A. V. Govorkov; In-Hwan Lee; S. J. Pearton; N. G. Kolin; I. L. Gazizov; V. M. Zalyetin

    2011-01-01

    Properties of GaN radiation detectors are analyzed. It is shown that present day epitaxial material is suitable for detection of alpha-particles with the charge collection efficiency close to 100%. Such detectors can operate at temperatures of at least 60°C and withstand irradiation with reactor neutrons fluences higher than 1015 cm-2. They keep the collection efficiency at 30% even after irradiation

  9. Study of the beta-delayed alpha-particle emission of [sup 16]N

    Microsoft Academic Search

    Z. Zhao; R. H. France; K. S. Lai; M. Gai; E. L. Wilds; R. A. Kryger; J. A. Winger; K. B. Beard

    1993-01-01

    The beta-delayed alpha-particle emission of [sup 16]N has been studied, with [sup 16]N nuclei produced using 80 MeV\\/nucleon [sup 18]O beams on [sup 9]Be targets. The [sup 16]N secondary nuclei were mass analyzed and separated from the reaction products using the Michigan State University A1200 isotope separator. A detector array, including four thin surface barrier detectors, a [ital p]-[ital i]-[ital

  10. Study of the beta-delayed alpha-particle emission of 16N

    Microsoft Academic Search

    Z. Zhao; R. H. France III; K. S. Lai; M. Gai; E. L. Wilds; R. A. Kryger; J. A. Winger; K. B. Beard

    1993-01-01

    The beta-delayed alpha-particle emission of 16N has been studied, with 16N nuclei produced using 80 MeV\\/nucleon 18O beams on 9Be targets. The 16N secondary nuclei were mass analyzed and separated from the reaction products using the Michigan State University A1200 isotope separator. A detector array, including four thin surface barrier detectors, a p-i-n diode, a Ge gamma-ray detector, and a

  11. Fusion alpha-particle losses in a high-beta rippled tokamak

    SciTech Connect

    Bunno, M.; Nakamura, Y. [Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan)] [Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Suzuki, Y. [National Institute for Fusion Science, Toki 509-5292 (Japan)] [National Institute for Fusion Science, Toki 509-5292 (Japan); Shinohara, K.; Matsunaga, G. [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan)] [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Tani, K. [Nippon Advanced Technology, Naka, Ibaraki 311-0102 (Japan)] [Nippon Advanced Technology, Naka, Ibaraki 311-0102 (Japan)

    2013-08-15

    In tokamak plasmas, the confinement of energetic ions depends on the magnetic field structure. If the plasma pressure is finite, the equilibrium current (i.e., the Pfirsch-Schlüter current and diamagnetic current) flows in the plasma to maintain the magnetohydrodynamic (MHD) equilibrium. These plasma currents generate poloidal and toroidal magnetic field and alter the field structure. Moreover, if we consider the non-axisymmetry of magnetic field structures such as toroidal field (TF) ripples, the non-axisymmetric component of the equilibrium current can alter TF ripples themselves. When the plasma beta becomes high, the changes in the field structure due to the equilibrium current might affect the confinement of energetic ions significantly. We intend to clarify how these currents alter the field structure and affect the confinement of alpha particles in high-beta plasma. The MHD equilibrium is calculated using VMEC and the orbits of fusion alpha particles are followed by using the fully three-dimensional magnetic field orbit-following Monte Carlo code. In relatively low-beta plasma (e.g., the volume-averaged beta value ?2%), the changes in the magnetic field component due to the plasma current negligibly affect the confinement of alpha particles except for the Shafranov shift effect. However, for ?3%, the diamagnetic effect reduces the magnetic field strength and significantly increases alpha-particle losses. In these high-beta cases, the non-axisymmetric field component generated by the equilibrium current also increases these losses, but not as effectively as compared to the diamagnetic effect.

  12. Accuracy testing using thick source alpha-particle spectroscopy for the U and Th series estimations.

    PubMed

    Michael, C T; Zacharias, N; Hein, A

    2010-01-01

    The new technique for the calculation of U and Th based on the alpha particle spectrum taken from a thick sample by using a silicon detector (PIPS) is tested and some technical problems are encountered and also some notifications for better accuracy are addressed. This technique which is mainly developed to be used for dose rate determination in TL, OSL and ESR dating applications, gives also the possibility for detecting and estimating possible disequilibrium in U and Th series. PMID:19900816

  13. Wurtzite Gallium Nitride as a scintillator detector for alpha particles (a Geant4 simulation)

    NASA Astrophysics Data System (ADS)

    Taheri, A.; Sheidaiy, M.

    2015-05-01

    Gallium Nitride has become a very popular material in electronics and optoelectronics. Because of its interesting properties, it is suitable for a large range of applications. This material also shows very good scintillation properties that make it a possible candidate for use as a charged particles scintillator detector. In this work, we simulated the scintillation and optical properties of the gallium nitride in the presence of alpha particles using Geant4. The results show that gallium nitride can be an appropriate choice for this purpose.

  14. Malignant transformation of human benign prostate epithelial cells by high linear energy transfer alpha-particles.

    PubMed

    Li, Hongzhen; Gu, Yongpeng; Miki, Jun; Hukku, Bharati; McLeod, David G; Hei, Tom K; Rhim, Johng S

    2007-09-01

    Although epidemiological studies have suggested a positive correlation between environmental radon exposure and prostate cancer, the mechanism involved is not clear. In the present study, we examined the oncogenic transforming potency of alpha-particles using non-tumorigenic, telomerase-immortalized human benign prostate epithelial cells. We report the malignant transformation of human benign prostate epithelial cells after a single exposure to 0.6 Gy dose of alpha-particles. Transformed cells showed anchorage-independent growth in soft agar and induced progressively growing tumors when transplanted into SCID mice. The tumors were characterized histologically as poorly differentiated adenocarcinomas. The cell line derived from tumor (SCID 5015), like the unirradiated cells, expressed cytokeratin 5, 8 and 18, NKX3.1 and AMACR. The malignant cells showed increased secretion of MMP2. Stepwise chromosomal changes in the progression to tumorigenicity were observed. Chromosome abnormalities were identified in both irradiated and tumorigenic cells relative to the non-irradiated control cells. Prominent changes in chromosomes 6, 11 and 16, as well as mutations and deletions of the p53 gene were observed in the tumor outgrowth and tumor cells. These findings provide the first evidence of malignant transformation of human benign prostate epithelial cells exposed to a single dose of alpha-particles. This model provides an opportunity to study the cellular and molecular alterations that occur in radiation carcinogenesis in human prostate cells. PMID:17671680

  15. Hormetic effect induced by alpha-particle-induced stress communicated in vivo between zebrafish embryos.

    PubMed

    Choi, V W Y; Cheung, A L Y; Cheng, S H; Yu, K N

    2012-11-01

    We report data showing that embryos of the zebrafish, Danio rerio, at 1.5 h post fertilization (hpf) subjected to a low-dose alpha-particle irradiation can release a stress signal into the water, which can be communicated to unirradiated bystander zebrafish embryos sharing the same water medium to induce a hormetic effect in the bystander embryos. Hormetic responses are characterized as biphasic dose-response relationships exhibiting a low-dose stimulation and a high-dose inhibition. The effects on the whole embryos were studied through quantification of apoptotic signals at 24 hpf through staining with the vital dye acridine orange, followed by counting the stained cells under a microscope. The results show that, for low alpha-particle dose, the number of apoptotic signals decreases in the irradiated embryos and also in the unirradiated bystander embryos having partnered with the irradiated embryos. These suggested that alpha-particle-irradiated zebrafish embryos could release a stress signal into the water, which could be communicated to unirradiated bystander zebrafish embryos sharing the same water medium to induce a hormetic effect in the bystander embryos. PMID:23050846

  16. Study of the beta-delayed alpha-particle emission of 16N

    NASA Astrophysics Data System (ADS)

    Zhao, Z.; France, R. H., III; Lai, K. S.; Gai, M.; Wilds, E. L.; Kryger, R. A.; Winger, J. A.; Beard, K. B.

    1993-07-01

    The beta-delayed alpha-particle emission of 16N has been studied, with 16N nuclei produced using 80 MeV/nucleon 18O beams on 9Be targets. The 16N secondary nuclei were mass analyzed and separated from the reaction products using the Michigan State University A1200 isotope separator. A detector array, including four thin surface barrier detectors, a p-i-n diode, a Ge gamma-ray detector, and a two-dimensional position sensitive parallel plate avalanche counter, was used for implantation and study of the separated nuclei. A beta-decay branching ratio of (1.3+/-0.3)×10-5 to the 1- state at 9.6 MeV and a centroid of 2.35+/-0.05 MeV for the beta-delayed alpha-particle emission were measured. These results are essential for the analysis of a high sensitivity measurement at Yale University of the low-energy beta-delayed alpha-particle emission of 16N, and for understanding the 12C(?,?)16O reaction in the helium burning process in massive stars.

  17. Electrostatic ion-acoustic-like instabilities in the solar wind with a backstreaming alpha particle beam

    SciTech Connect

    Gomberoff, L. [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Santiago (Chile); Gomberoff, K. [Department of Physics, Technion, Haifa 32000 (Israel); Deutsch, A. [Rafael, P.O. Box 2250, Haifa 31021 (Israel)

    2010-06-15

    Nonlinear electrostatic instabilities have been shown to occur frequently and under very different conditions in plasma with two ion beams such as the fast solar wind. These instabilities can be triggered when the phase velocity of electrostatic ion-acoustic waves propagating forward and backward relative to the interplanetary magnetic field overlaps due to the presence of a finite amplitude of circularly polarized wave. The instabilities can be triggered by waves supported by the same ion component, or by waves supported by different ion components. By assuming a beam of alpha particles moving backward relative to the external magnetic field, as observed in some events in the fast solar wind, it is shown that a very small negative drift velocity of the alpha particle beam relative to the core plasma--a few percent of the local Alfven velocity--can trigger a very rich variety of nonlinear electrostatic acousticlike instabilities. Their growth rates can be rather large and they persist for larger negative alpha particles drift velocities and temperatures.

  18. Acceleration of low-energy protons and alpha particles at interplanetary shock waves

    NASA Technical Reports Server (NTRS)

    Scholer, M.; Hovestadt, D.; Ipavich, F. M.; Gloeckler, G.

    1983-01-01

    The low-energy protons and alpha particles in the energy range 30 keV/charge to 150 keV/charge associated with three different interplanetary shock waves in the immediate preshock and postshock region are studied using data obtained by the ISEE 3. The spatial distributions in the preshock and postshock medium are presented, and the dependence of the phase space density at different energies on the distance from the shock and on the form of the distribution function of both species immediately at the shock is examined. It is found that in the preshock region the particles are flowing in the solar wind frame of reference away from the shock and in the postshock medium the distribution is more or less isotropic in this frame of reference. The distribution function in the postshock region can be represented by a power law in energy which has the same spectral exponent for both protons and alpha particles. It is concluded that the first-order Fermi acceleration process can consistently explain the data, although the spectra of diffuse bow shock associated particles are different from the spectra of the interplanetary shock-associated particles in the immediate vicinity of the shock. In addition, the mean free path of the low energy ions in the preshock medium is found to be considerably smaller than the mean free path determined by the turbulence of the background interplanetary medium.

  19. Coinhibition of viral interferon induction by Benzo(. alpha. )pyrene in association with occupation-related particles

    SciTech Connect

    Hahon, N. (National Inst. for Occupational Safety and Health, Morgantown, WV (United States) West Virginia Univ., Morgantown (United States)); Booth, J.A. (West Virginia Univ., Morgantown (United States)); Flowers, L. (Univ. of Pennsylvania, Philadelphia (United States))

    1990-06-01

    Benzo({alpha})pyrene (B(a)P) in combination with coal, asbestos, silicate, or metal particles was studied for its inhibitory effects on interferon-{alpha}/{beta} induction by influenza virus in rhesus monkey kidney (LLC-MK{sub 2}) cell monolayers. B(a)P per se had no adverse effect on the induction process. However, when cell cultures were pretreated with B(a)P that was bioactivated by rat liver S9 homogenate, from 52 to 65% inhibition of interferon induction occurred. Significantly greater depression (coinhibition) of viral interferon induction (>83%) resulted when bioactivated B(a)P was incorporated with coal particles representative of coal rank (anthracite, bituminous, lignite, peat). Coinhibition affected by bioactivated B(a)P was coal rank-independent but any interferon inhibitory activity affected by coal particles per se was coal rank-independent. When metals (aluminum, aluminum oxide, ferric oxide, nickel, or chromium) or asbestos fibers were individually mixed with bioactivated B(a)P, coinhibition of cellular interferon synthesis also resulted which was significantly greater than that manifested by bioactivated B(a)P or particles per se. Coinhibition of interferon induction by silicates and the bioactivated hydrocarbon was not in evidence although some silicates alone partially inhibited the induction process. Viral interferon induction was inhibited in a dose-response manner by B(a)P ({+-}S9) in combination with selected particles.

  20. Preferential energization of alpha particles in polar coronal holes at one solar radius above the photosphere

    NASA Astrophysics Data System (ADS)

    Chakravarty, Aniruddha; Bose, M.

    2015-04-01

    Heating of polar coronal holes (PCH) during solar minimum and acceleration of the fast solar wind issuing therefrom lack comprehensive theoretical understanding. Wave-particle interactions are considered to have crucial effects on the extreme properties of heavy ions in the collisionless region of the PCH. In this paper, we have presented a novel sensitivity analysis to investigate plasma heating by radio waves at lower hybrid (LH) frequencies. We have employed a three-fluid Maxwell model comprising electrons, protons, and ?-particles at around two solar radii heliocentric distance in the PCH and derived a dispersion relation as a 13th-order polynomial for the frequency. Our model provides indications of preferential heating of ?-particles in comparison with protons by means of LH instabilities. We have employed the electron velocity and spatial charge distribution as our basic study tools so as to show the effects of alpha-proton differential mass and differential perpendicular velocity on the preferential heating of ?-particles.

  1. Alpha particle transport in the presence of ballooning type electrostatic driftwaves

    NASA Astrophysics Data System (ADS)

    Nishimura, Y.; Huang, B.; Cheng, C. Z.

    2015-07-01

    Employing Hamiltonian mechanics, the transport of fusion born alpha particles in the presence of driftwave turbulence is investigated. An analytical turbulence model based on the toroidal drift eigenmode is employed for guiding center orbit-following calculations. It is shown that high energy particles are less susceptible to driftwave turbulence. The passing particle transport is due to overlapping of guiding center electric islands whose widths are inversely proportional to the square root of the parallel velocity. For trapped particles, through a coordinate transformation from the poloidal angle and the parallel velocity to the action-angle variables, the resonance between the bounce motion and the toroidal precession motion, which can cause secondary island formation in the phase space, is demonstrated.

  2. Effects of alpha particles on the angular momentum loss from the Sun

    E-print Network

    Bo Li; Xing Li

    2006-06-07

    The classic Weber-Davis model of the solar wind is reconsidered by incorporating alpha particles and by allowing the solar wind to flow out of the equatorial plane in an axisymmetrical configuration. In the ion momentum equations of the solar wind, the ion gyro-frequency is many orders of magnitude higher than any other frequency. This requires that the difference between proton and alpha velocity vectors be aligned with the background magnetic field. With the aid of this alignment condition, the governing equations of the multi-fluid solar wind are derived from the standard transport equations. The governing equations are numerically solved along a prescribed meridional magnetic field line located at colatitude $70^\\circ$ at 1AU and a steady state fast solar wind solution is found. A general analysis concludes, in agreement with the Weber-Davis model, that the magnetic field helps the coronal plasma to achieve an effective corotation out to the Alfv\\'enic radius, where the poloidal Alfv\\'enic Mach number $M_T$ equals unity ($M_T$ is defined by equation (\\ref{eq:mach})). The model computations show that, magnetic stresses predominate the angular momentum loss of the Sun. For the fast wind considered, the proton contribution to the angular momentum loss, which can be larger than the magnetic one, is almost completely canceled by the alpha particles that develop an azimuthal speed in the direction opposite to the solar rotation. The Poynting flux associated with the azimuthal components is negligible in the energy budget. However, the solar rotation can play some role in reducing the relative speed between alpha particles and protons for low latitude fast solar wind streams in interplanetary space.

  3. Quantum 1/f noise in nondegenerate semiconductors and emission statistics of alpha particles

    SciTech Connect

    Kousik, G.S.

    1985-01-01

    Charged particle scattering is accompanied by the emission of soft photons. Handel's theory of 1/f noise, based on the infrared divergent coupling of the system to the electromagnetic field or other elementary excitations, states that the current associated with a beam of scattered particles will exhibit 1/f noise. The fraction of the particles scattered with an energy loss epsilon to soft photon emission is proportional to 1/epsilon and herein lies the origin of the quantum theory of 1/f noise. The 1/f noise caused by mobility fluctuations in semiconductors is related to the scattering cross section fluctuation given by Handel's theory, through the relaxation time. Results are presented of the detailed calculation of mobility fluctuation 1/f noise and Hooge parameter in nondegenerate semiconductors. Numerical results are given for silicon and gallium arsenide. Data obtained from extensive measurements on counting techniques for alpha-particle radioactive decay from a source containing /sub 94/Pu/sup 239/, /sub 95/Am/sup 241/ and /sub 96/Cm/sup 244/ are presented. These data show that the statistics are non-Poissonian for large counting times (of the order of 1000 minutes) contrary to the popular belief that alpha decay is an example of Poissonian statistics.

  4. Exciton dynamics in alpha-particle tracks in organic crystals: Magnetic field study of the scintillation in tetracene crystals

    Microsoft Academic Search

    Nicholas E. Geacintov; Michael Binder; Charles E. Swenberg; Martin Pope

    1975-01-01

    The mechanisms of scintillation of organic crystals bombarded by alpha particles are discussed in terms of the current knowledge of exciton dynamics, which has been derived from a study of the photofluorescence of crystals such as anthracene and tetracene. The scintillation of tetracene excited by 4.4-MeV alpha particles incident in a direction perpendicular to the ab plane has been studied

  5. Deep level defects and carrier removal due to proton and alpha particle irradiation of InP

    Microsoft Academic Search

    George C. Rybicki; Christian A. Zorman

    1994-01-01

    Deep level transient spectroscopy and capacitance voltage measurements of the defect introduction rates and carrier removal rates for 2 MeV proton and 2 MeV alpha particle irradiations in p-type InP have been performed. The carrier removal rate for 2 MeV protons was 6500 cm?1 and for 2 MeV alpha particles was 73 400 cm?1, or 12 times higher. The defect

  6. Absolute number of photons produced by alpha-particles in liquid and gaseous xenon

    NASA Astrophysics Data System (ADS)

    Miyajima, Mitsuhiro; Sasaki, Shinichi; Shibamura, Eido

    1992-02-01

    The Ws which is defined as an average energy expended per scintillation photon, was found to be 16.3 ± 0.3 eV for alpha-particles in liquid xenon, and 49.6 ± 1.1 eV in gaseous xenon, respectively. These results followed from the number of photoelectrons measured with a VUV sensitive photomultiplier tube, which was used as a photodiode. The number of photoelectrons from the photomultiplier photocathode was measured absolutely with a well calibrated charge sensitive amplifier system as a function of distance between the alpha-source and the photomultiplier photocathode. The detection geometries included both reflective and nonreflective walls. The data were well fitted to corresponding curves obtained with a Monte Carlo simulation, and yielded the total number of scintillation photons.

  7. Orbit-averaged drift kinetic equation for the study of alpha-particle transport in tokamaks

    SciTech Connect

    Sager, G.T.; Miley, G.H. (Illinois Univ., Urbana, IL (United States). Fusion Studies Lab.); Burrell, K.H. (General Atomics Co., San Diego, CA (United States))

    1990-11-01

    Neoclassical transport of minority suprathermal alpha particles is investigated. This paper departs from previous investigations in that (a) the banana-width ordering parameter {rho}{sub {theta}}/L is not formally restricted to be a small parameter and (b) a linearized collision operator that retains the effects of pitch-angle scattering, electron and ion drag, and speed diffusion is used. A step model approximation for the large-aspect-ratio, circular-cross-section tokamak magnetic field is adopted to simplify the orbit-averaging procedure. Assuming that the suprathermal alphas are in the banana regime, an asymptotic expansion in {tau}{sub B}/{tau}{sub S} {much lt} l is carried out.

  8. Electron-hole pair generation in SiC high-temperature alpha particle detectors

    NASA Astrophysics Data System (ADS)

    Garcia, Timothy R.; Kumar, Ashutosh; Reinke, Benjamin; Blue, Thomas E.; Windl, Wolfgang

    2013-10-01

    We demonstrate alpha-particle detection in an n-type 4H-SiC Schottky diode detector up to a temperature of 500 °C using an Am-241 disc source. The measured spectra were used to calculate the electron-hole pair creation energy in 4H-SiC and its non-bandgap contribution, which are both found to decrease with increasing temperature. The full width at half maximum (FWHM) of the measured alpha-energy peaks was found to increase exponentially with temperature due to an exponential increase of leakage current. For our measurement system, above 300 °C, where the leakage current was 10-6 A, this increase exceeded the FWHM at room temperature.

  9. Electron-Hole Pair Generation in SiC High-Temperature Alpha Particle Detectors

    E-print Network

    Garcia, Timothy R; Reinke, Benjamin T; Blue, Thomas E; Windl, Wolfgang E

    2013-01-01

    We demonstrate alpha-particle detection in an n-type 4H-SiC Schottky diode detector up to an unprecedented temperature of 500 {\\deg}C using an Am-241 disc source. The measured spectra were used to calculate the electron-hole pair creation energy in 4H-SiC and its non-bandgap contribution, which are both found to decrease with increasing temperature. The full width at half maximum (FWHM) of the measured alpha-energy peaks was found to increase exponentially with temperature due to an exponential increase of leakage current. For our measurement system, above 300 {\\deg}C, where the leakage current was 10-6 A, this increase exceeded the FWHM at room temperature.

  10. Beams of protons and alpha particles greater than approximately 30 keV/charge from the earth's bow shock

    NASA Technical Reports Server (NTRS)

    Scholer, M.; Ipavich, F. M.; Gloeckler, G.

    1981-01-01

    Two beamlike particle events (30 keV/charge to 160 keV/charge) upstream of the earth's bow shock have been investigated with the Max-Planck-Institut/University of Maryland ultralow energy and charge analyzer on ISEE 1. These beams consist of protons as well as of alpha particles, and the spectra are generally steep and are decreasing with increasing energy. During one event the spectra of both protons and alpha particles have a maximum at approximately 65 keV/charge. During these events, the interplanetary magnetic field through the satellite position was almost tangent to the bow shock, and application of the theory of acceleration predicts acceleration of a solar wind particle up to 60 keV/nucleon in a single reflection. The observation of reflected protons as well as alpha particles has implications for the physical reflection process usually not discussed in acceleration theories.

  11. Investigations of factors affecting the use of uranium metal as a source of alpha particles for the evaluation of alpha track detectors

    E-print Network

    Voirin, Marc

    1994-01-01

    , an uranium foil was used as the alpha particle source. The foil created new problems which needed to be studied in detail. Among these problems, the effect of the thickness of the oxide layer on the uranium metal foil surface was the most important. To study...

  12. Investigations of factors affecting the use of uranium metal as a source of alpha particles for the evaluation of alpha track detectors 

    E-print Network

    Voirin, Marc

    1994-01-01

    , an uranium foil was used as the alpha particle source. The foil created new problems which needed to be studied in detail. Among these problems, the effect of the thickness of the oxide layer on the uranium metal foil surface was the most important. To study...

  13. Chemistry of Rocks and Soils in Gusev Crater from the Alpha Particle X-ray Spectrometer

    NASA Technical Reports Server (NTRS)

    Gellert, R.; Rieder, R.; Anderson, R. C.; Brueckner, J.; Clark, B. C.; Dreibus, G.; Economou, T.; Klingelhoefer, G.; Lugmair, G. W.; Ming, D. W.

    2005-01-01

    The alpha particle x-ray spectrometer on the Spirit rover determined major and minor elements of soils and rocks in Gusev crater in order to unravel the crustal evolution of planet Mars. The composition of soils is similar to those at previous landing sites, as a result of global mixing and distribution by dust storms. Rocks (fresh surfaces exposed by the rock abrasion tool) resemble volcanic rocks of primitive basaltic composition with low intrinsic potassium contents. High abundance of bromine (up to 170 parts per million) in rocks may indicate the alteration of surfaces formed during a past period of aqueous activity in Gusev crater.

  14. Damage of EUV optical coatings induced by alpha-particles bombardment

    NASA Astrophysics Data System (ADS)

    Pelizzo, M. G.; Zuccon, S.; Napolitani, E.; Corso, A. J.; Zuppella, P.; Tessarolo, E.; Nardello, M.; Gerlin, F.; Naletto, G.; Fineschi, S.; Antonucci, E.

    2014-09-01

    Future solar missions will investigate the Sun from very close distances and optical components are constantly exposed to low energy ions irradiation. Single layer thin films as well as extreme ultraviolet multilayer coatings have been exposed to low energy alpha particles (4keV). In order to change the total dose accumulated, for each ion fluency the time of exposure was varied. The experiment was carried out considering typical doses accumulated during the ESA Solar Orbiter mission. Results show that ion implantation affects the performances of both single and multilayer coatings.

  15. Chemistry of rocks and soils in Gusev Crater from the alpha particle x-ray spectrometer.

    PubMed

    Gellert, R; Rieder, R; Anderson, R C; Brückner, J; Clark, B C; Dreibus, G; Economou, T; Klingelhöfer, G; Lugmair, G W; Ming, D W; Squyres, S W; D'Uston, C; Wänke, H; Yen, A; Zipfel, J

    2004-08-01

    The alpha particle x-ray spectrometer on the Spirit rover determined major and minor elements of soils and rocks in Gusev crater in order to unravel the crustal evolution of planet Mars. The composition of soils is similar to those at previous landing sites, as a result of global mixing and distribution by dust storms. Rocks (fresh surfaces exposed by the rock abrasion tool) resemble volcanic rocks of primitive basaltic composition with low intrinsic potassium contents. High abundance of bromine (up to 170 parts per million) in rocks may indicate the alteration of surfaces formed during a past period of aqueous activity in Gusev crater. PMID:15297665

  16. Chemistry of rocks and soils at Meridiani Planum from the Alpha Particle X-ray Spectrometer.

    PubMed

    Rieder, R; Gellert, R; Anderson, R C; Brückner, J; Clark, B C; Dreibus, G; Economou, T; Klingelhöfer, G; Lugmair, G W; Ming, D W; Squyres, S W; d'Uston, C; Wänke, H; Yen, A; Zipfel, J

    2004-12-01

    The Alpha Particle X-ray Spectrometer on the Opportunity rover determined major and minor elements of soils and rocks in Meridiani Planum. Chemical compositions differentiate between basaltic rocks, evaporite-rich rocks, basaltic soils, and hematite-rich soils. Although soils are compositionally similar to those at previous landing sites, differences in iron and some minor element concentrations signify the addition of local components. Rocky outcrops are rich in sulfur and variably enriched in bromine relative to chlorine. The interaction with water in the past is indicated by the chemical features in rocks and soils at this site. PMID:15576611

  17. A Metastable Alpha-Particle Irradiation Induced Defect in n-GaAs

    NASA Astrophysics Data System (ADS)

    Auret, F.; Erasmus, Rudolph; Goodman, Stewart

    1994-04-01

    We report the introduction and characterization of a metastable alpha-particle irradiation induced defect, E?8, in n-GaAs by deep level transient spectroscopy (DLTS) using Schottky barrier diodes. The E?8 defect, with an energy level 0.18 eV below the conduction band, as determined by low-field DLTS measurements, could be reversibly transformed (removed and re-introduced) by employing zero and reverse bias anneals, respectively, in the 100 140 K temperature range. The transformation kinetics of E?8 displayed first order behaviour and was found to be charge state dependant.

  18. Mapping alpha-Particle X-Ray Fluorescence Spectrometer (Map-X)

    NASA Technical Reports Server (NTRS)

    Blake, D. F.; Sarrazin, P.; Bristow, T.

    2014-01-01

    Many planetary surface processes (like physical and chemical weathering, water activity, diagenesis, low-temperature or impact metamorphism, and biogenic activity) leave traces of their actions as features in the size range 10s to 100s of micron. The Mapping alpha-particle X-ray Spectrometer ("Map-X") is intended to provide chemical imaging at 2 orders of magnitude higher spatial resolution than previously flown instruments, yielding elemental chemistry at or below the scale length where many relict physical, chemical, and biological features can be imaged and interpreted in ancient rocks.

  19. Effects of pre-equilibrium nucleon emission on excitation functions of various reactions in vanadium induced by alpha particles

    Microsoft Academic Search

    N L Singh; S Mukherjee; A V Mohan Rao; L Chaturvedi; P P Singh

    1995-01-01

    Excitation functions for the 51V(( alpha ,n), ( alpha ,3n), ( alpha ,p3n), ( alpha ,p6n), ( alpha , alpha 3n), ( alpha , alpha 2pn), ( alpha ,2 alpha ), ( alpha ,2 alpha n) and ( alpha ,2 alpha 3n)) reactions have been measured up to 120 MeV using the stacked foil technique with a view to improving

  20. Comparitive Ionization Energies for Protons, Deuterons and Alpha Particles in High Purity Germanium and Si(Li) Nuclear Radiation Detectors

    Microsoft Academic Search

    M. Martini; T. W. Raudorf; W. R. Stott; J. C. Waddington

    1975-01-01

    Relative measurements of the average energy, ¿, expended for electron-hole pair generation in silicon and high purity germanium detectors were made using 10 to 19 MeV proton, deuteron and alpha particle beams. The results show that ¿ is constant for different particles in high purity germanium detectors but not in silicon detectors. A model is presented which could explain both

  1. Alfven waves, alpha particles, and pickup ions in the solar wind

    NASA Technical Reports Server (NTRS)

    Goldstein, B. E.; Neugebauer, M.; Smith, E. J.

    1995-01-01

    Past studies of the properties of Alfven waves in the solar wind have indicated that (1) the amplitude of the velocity fluctuations is almost always smaller than expected on the basis of the amplitude of the field fluctuations, even when the anisotropy of the plasma is taken into account, and (2) the alpha particles do not participate in the wave motions because they 'surf' on the waves carried by the proton fluid. Ulysses data are used to demonstrate that (1) the discrepancy between the velocity and field fluctuations is greater at high heliographic latitudes than in the ecliptic plane, and (2) the alphas do participate in the waves, being either in phase or out of phase with the proton motions depending on whether the differential flow speed between the alphas and protons is greater than or less than the 'observed' wave speed, B(sub o)(delta v squared / delta B squared)exp 1/2, as determined from the ratio of the amplitudes of the velocity and magnetic fluctuations. It is proposed that the modification of Alfven wave propagation speed is due to pressure anisotropies resulting from asymmetric distributions of interstellar pickup ions. If the proposed explanation is correct, it indicates that scattering of pickup ions onto a (bi)spherical shell may not be as complete as generally supposed.

  2. Alpha particle beam interactions with Fe-based FeCo-based amorphous magnets

    SciTech Connect

    Sorescu, M. [Duquesne Univ., Pittsburgh, PA (United States). Physics Dept.; Barb, D. [Inst. of Atomic Physics, Bucharest-Magurele (Romania)

    1997-12-01

    Samples of Fe{sub 78}B{sub 13}Si{sub 9} and Fe{sub 66}Co{sub 18}B{sub 15}Si{sub 1} metallic glasses were irradiated with alpha particle beams (W = 2.8 MeV) using radiation doses of 10{sup 16} and 10{sup 17} cm{sup {minus}2}. Irradiation-induced effects on the magnetic and structural properties of alloy samples were studied by transmission and conversion electron Moessbauer spectroscopy. The evolution of phases and microstructure during the radiation-induced amorphous-to-crystalline transformation was found to depend on the particle flux and sample composition. Differences between bulk and surface irradiation behaviors were demonstrated.

  3. Effects of gravitational-wave recoil on the dynamics and growth of supermassive black holes

    E-print Network

    Laura Blecha; Abraham Loeb

    2008-08-01

    Simulations of binary black hole mergers indicate that asymmetrical gravitational wave (GW) emission can cause black holes to recoil at speeds up to thousands of km/s. These GW recoil events can dramatically affect the coevolution of recoiling supermassive black holes (SMBHs) and their host galaxies. However, theoretical studies of SMBH-galaxy evolution almost always assume a stationary central black hole. In light of the numerical results on GW recoil velocities, we relax that assumption here and consider the consequences of recoil for SMBH evolution. We follow the trajectories of SMBHs ejected in a smooth background potential that includes both a stellar bulge and a multi-component gaseous disk. In addition, we calculate the accretion rate onto the SMBH as a function of time using a hybrid prescription of viscous (alpha-disk) and Bondi accretion. We find that recoil kicks between 100 km/s and the escape speed cause SMBHs to wander through the galaxy and halo for about 1 Myr - 1 Gyr before settling back to the galactic center. However, the mass accreted during this time is roughly constant at about 10% of the initial mass, independent of the recoil velocity. This indicates that while large recoils may disrupt active galactic nuclei feedback processes, recoil itself is an effective means of regulating SMBH growth. Recoiling SMBHs may be observable as spatially or kinematically offset quasars, but finding such systems could be challenging, because the largest offsets correspond to the shortest quasar lifetimes.

  4. Quantum 1/f noise in non-degerate semiconductors and emission statistics of alpha particles

    SciTech Connect

    Kousik, G.S.

    1985-01-01

    Charged particle scattering is accompanied by the emission of soft photons. Handel's theory of 1/f noise, based on the infrared divergent coupling of the system to the electromagnetic field or other elementary excitations, states that the current associated with a beam of scattered particles will exhibit 1/f noise. The fraction of the particles scattered with an energy loss epsilon to soft photon emission is proportional to 1/epsilon and herein lies the origin of the quantum theory of 1/f noise. The 1/f noise caused by mobility fluctuations in semiconductors is related to the scattering cross section fluctuation given by Handel's theory, through the relaxation time. Chapters Two through Five of this dissertation presents the results of the detailed calculation of mobility fluctuation 1/f noise and Hooge parameter in nondegenerate semiconductors. Numerical results are given for silicon and gallium arsenide. Data obtained from extensive measurements on counting techniques for alpha-particles radioactive decay from a source containing /sub 94/Pu/sup 239/, /sub 95/Am/sup 241/ and /sub 96/Cm/sup 244/ are presented in Chapters Six and Seven of this dissertation. These data show that the statistics are non-Poissonian for large counting times (of the order of 1000 minutes) contrary to the popular belief that alpha-decay is an example of Poissonian statistics. Measurements of the Allan variance indicated the presence of a slow Lorentzian flicker noise and 1/f noise and the magnitude of the noise for large counting times is considerably larger than that predicted by Poissonian statistics.

  5. Retention studies of recoiling daughter nuclides of 225Ac in polymer vesicles.

    PubMed

    Wang, G; de Kruijff, R M; Rol, A; Thijssen, L; Mendes, E; Morgenstern, A; Bruchertseifer, F; Stuart, M C A; Wolterbeek, H T; Denkova, A G

    2014-02-01

    Alpha radionuclide therapy is steadily gaining importance and a large number of pre-clinical and clinical studies have been carried out. However, due to the recoil effects the daughter recoil atoms, most of which are alpha emitters as well, receive energies that are much higher than the energies of chemical bonds resulting in decoupling of the radionuclide from common targeting agents. Here, we demonstrate that polymer vesicles (i.e. polymersomes) can retain recoiling daughter nuclei based on an experimental study examining the retention of (221)Fr and (213)Bi when encapsulating (225)Ac. PMID:24374072

  6. Observation of lunar radon emanation with the Apollo 15 alpha particle spectrometer.

    NASA Technical Reports Server (NTRS)

    Gorenstein, P.; Bjorkholm, P.

    1972-01-01

    The alpha particle spectrometer, a component of the orbital Sim Bay group of 'geochemistry' experiments on Apollo 15, was designed to detect alpha particles emitted during the decay of isotopes of radon gas and her daughter products. The purpose was to measure the gross activity of radon on the lunar surface and to find possible regions of increased local activity. Results are presented from a partial analysis of Apollo 15 data. For the moon as a whole, Rn220 was not observed and the upper limit on its decay rate above the lunar surface is 0.00038 disintegrations/sq cm-sec. Rn222 was marginally observed. Possible variations of radon activity on the lunar surface are being investigated. Po210 (a daughter product of Rn222) has been detected in a broad region from west of Mare Crisium to the Van de Graaff-Orlov region. The observed count rate is (4.6 plus or minus 1.4) x 0.001 disintegrations/sq cm-sec. The observed level of Po210 activity is in excess of the amount that would be in equilibrium with Rn222 by about an order of magnitude. This implies that larger levels of radon emanation have occurred on the moon within a time scale of 10 to 100 years.

  7. Results of the Alpha-Particle-X-Ray Spectrometer on Board of the Mars Exploration Rovers

    NASA Technical Reports Server (NTRS)

    Geller, R.; Zipfel, J.; Brueckner, J.; Dreibus, G.; Lugmair, G.; Rieder, R.; Waenke, H.; Klingelhoefer, G.; Clark, B. C.; Ming, D. W.

    2005-01-01

    The Mars Exploration Rovers Spirit and Opportunity landed at Gusev crater and Meridiani Planum. The Alpha Particle X-ray Spectrometer (APXS) is part of the instrument suite on both rovers. It is equipped with six 244Cm sources which provide x-ray excitation with alpha-particles (PIXE) and x-ray radiation (XRF). This combination allows x-ray spectroscopy of elements from Na to Br in the energy range of 0.9 to 16 keV. X-ray detectors with a high energy resolution of 160 eV at Fe K allow us to separate even closely spaced energy peaks, such as Na, Mg, Al and Si. The APXS is attached to the rover s arm and provides in-situ measurements of the chemical composition of soils, surfaces of rocks and outcrops and their abraded surfaces. This abstract gives an overview of APXS results obtained during the first year of operation on both landing sites.

  8. Selective Alpha-Particle Mediated Depletion of Tumor Vasculature with Vascular Normalization

    PubMed Central

    Seshan, Surya V.; Kappel, Barry J.; Chattopadhyay, Debjit; May, Chad; McDevitt, Michael R.; Nolan, Daniel; Mittal, Vivek; Benezra, Robert; Scheinberg, David A.

    2007-01-01

    Background Abnormal regulation of angiogenesis in tumors results in the formation of vessels that are necessary for tumor growth, but compromised in structure and function. Abnormal tumor vasculature impairs oxygen and drug delivery and results in radiotherapy and chemotherapy resistance, respectively. Alpha particles are extraordinarily potent, short-ranged radiations with geometry uniquely suitable for selectively killing neovasculature. Methodology and Principal Findings Actinium-225 (225Ac)-E4G10, an alpha-emitting antibody construct reactive with the unengaged form of vascular endothelial cadherin, is capable of potent, selective killing of tumor neovascular endothelium and late endothelial progenitors in bone-marrow and blood. No specific normal-tissue uptake of E4G10 was seen by imaging or post-mortem biodistribution studies in mice. In a mouse-model of prostatic carcinoma, 225Ac-E4G10 treatment resulted in inhibition of tumor growth, lower serum prostate specific antigen level and markedly prolonged survival, which was further enhanced by subsequent administration of paclitaxel. Immunohistochemistry revealed lower vessel density and enhanced tumor cell apoptosis in 225Ac-E4G10 treated tumors. Additionally, the residual tumor vasculature appeared normalized as evident by enhanced pericyte coverage following 225Ac-E4G10 therapy. However, no toxicity was observed in vascularized normal organs following 225Ac-E4G10 therapy. Conclusions The data suggest that alpha-particle immunotherapy to neovasculature, alone or in combination with sequential chemotherapy, is an effective approach to cancer therapy. PMID:17342201

  9. Non-equilibrium effects in alpha-particle-induced reactions in light, medium and heavy nuclei up to 120 MeV

    Microsoft Academic Search

    J. Rama Rao; A. V. Mohan Rao; S. Mukherjee; R. Upadhyay; N. L. Singh; S. Agarwal; L. Chaturvedi; P. P. Singh

    1987-01-01

    Alpha-particle-induced reactions on the target elements vanadium, niobium and holmium were investigated in the energy range from 10 to 120 MeV, using the foil stack activation technique and Ge(Li) gamma-ray spectroscopy. The excitation functions of six reactions of the ( alpha , xn) type were studied, of which three reactions 51V( alpha ,n)54Mn, 165Ho( alpha ,2n)167Tm and 165Ho( alpha ,4n)165Tm

  10. TEST PROCEDURE FOR GROSS ALPHA PARTICLE ACTIVITY IN DRINKING WATER: INTERLABORATORY COLLABORATIVE STUDY

    EPA Science Inventory

    Gross alpha activity values were calculated with four different alpha emitting radionuclide standard counting efficiencies to see which standard was best for gross alpha activity determinations. Thorium-230, a pure alpha emitter, appeared to be the best standard for gross alpha c...

  11. Feasibility study on the use of polyallyldiglycol-carbonate cell dishes in TUNEL assay for alpha particle radiobiological experiments

    NASA Astrophysics Data System (ADS)

    Chan, K. F.; Yum, E. H. W.; Wan, C. K.; Fong, W. F.; Yu, K. N.

    2007-08-01

    In the present work, we have studied the feasibility of a method based on polyallyldiglycol-carbonate (PADC) films to investigate the effects of alpha particles on HeLa cervix cancer cells. Thin PADC films with thickness of about 20 ?m were prepared from commercially available CR-39 films by chemical etching to fabricate custom-made petri dishes for cell culture, which could accurately record alpha particle hit positions. A special method involving "base tracks" for aligning the images of cell nuclei and alpha particle hits has been proposed, so that alpha particle transversals of cell nuclei can be visually counted. Radiobiological experiments were carried out to induce DNA damages, with the TdT-mediated d UTP Nick- End Labeling (TUNEL) fluorescence method employed to detect DNA strand breaks. The staining results were investigated by flow cytometer. The preliminary results showed that more strand breaks occurred in cells hit by alpha particles with lower energies. Moreover, large TUNEL positive signals were obtained even with small percentages of cells irradiated and TUNEL signals were also obtained from non-targeted cells. These provided evidence for the bystander effect.

  12. Scattering of 42 MeV alpha particles from copper-65

    NASA Technical Reports Server (NTRS)

    Stewart, W. M.; Seth, K. K.

    1973-01-01

    Beams of 42-MeV alpha particles were elastically and inelastically scattered from Cu-65 in an attempt to excite states which may be described in terms of an excited core model. Angular distributions were measured for 17 excited states. Seven of the excited states had angular distributions similar to a core quadrupole excitation and eight of the excited states had angular distributions similar to a core octupole excitation. The excited state at 2.858 MeV had an angular distribution which suggests that it may have results from the particle coupling to a two-phonon core state. An extended particle-core coupling calculation was performed and the predicted energy levels and reduced transition probabilities compared to the experimental data. The low lying levels are described quite well and the wavefunctions of these states explain the large spectroscopic factors measured in stripping reactions. For Cu-65 the coupling of the particle to the core is no larger weak as in the simpler model, and configuration mixing results.

  13. Differential Effects of Alpha-Particle Radiation and X-Irradiation on Genes Associated with Apoptosis

    PubMed Central

    Chauhan, Vinita; Howland, Matthew; Chen, Jeremy; Kutzner, Barbara; Wilkins, Ruth C.

    2011-01-01

    This study examined differential effects of alpha-(?-) particle radiation and X-rays on apoptosis and associated changes in gene expression. Human monocytic cells were exposed to ?-particle radiation and X-rays from 0 to 1.5?Gy. Four days postexposure, cell death was measured by flow cytometry and 84 genes related to apoptosis were analyzed using real-time PCR. On average, 33% of the cells were apoptotic at 1.5?Gy of ?-particle radiation. Transcript profiling showed statistical expression of 15 genes at all three doses tested. Cells exposed to X-rays were <5% apoptotic at ~1.5?Gy and induced less than a 2-fold expression in 6 apoptotic genes at the higher doses of radiation. Among these 6 genes, Fas and TNF-? were common to the ?-irradiated cells. This data suggests that ?-particle radiation initiates cell death by TNF-? and Fas activation and through intermediate signalling mediators that are distinct from X-irradiated cells. PMID:22091383

  14. Study of excitation functions of alpha-particle induced nuclear reactions on holmium for 167Tm production.

    PubMed

    Tárkányi, F; Hermanne, A; Király, B; Takács, S; Ignatyuk, A V

    2010-03-01

    (167)Tm is a candidate radioisotope for both nuclear medicine diagnostics and therapy due to its emitted Auger-electrons, low energy X- and gamma-rays. In the frame of a systematic study of excitation functions for production of medically relevant radioisotopes by charged particle induced reactions on rare earths, the (165)Ho(alpha,2n)(167)Tm reaction and the (165)Ho(alpha,n)(168)Tm, (165)Ho(alpha,3n)(166)Tm, (165)Ho(alpha,4n)(165)Tm side reactions were measured up to 40 MeV by the stacked foil irradiation technique and gamma-ray spectroscopy. The measured results were compared to the ALICE-IPPE and EMPIRE-II theoretical curves. Thick target yields, impurity levels and specific activities were deduced and compared with the same parameters for other charged particle production routes of (167)Tm. PMID:20022515

  15. Alpha-particle-driven instability of alfven waves in a tandem mirror. Final summary report, 21 February-20 May 1985

    SciTech Connect

    Ho, S.K.

    1985-08-20

    Alpha particles born at D-T fusion are mirror confined in the tandem mirror due to their relatively high energy. Therefore, they have a loss-cone type distribution in the velocity space. This anisotropy is susceptible to microinstability. The objective of this work is to study the possible instability that can be driven by the alpha loss-cone. The low frequency (at the order of the ion cyclotron frequency) wave spectrum is studied to seek the waves that can be destabilized by the alphas. The radial mode structure is found for the growth rate calculation. The alpha particle distribution with a loss-cone is obtained from a Legendre function expansion and a diffusion front method. The growth rate of the instability is formulated from linear stability theory and computed numerically. A marginal stability boundary in the ion density and temperature parameters is calculated.

  16. Status and Prospects of the HERMES Recoil Detector

    E-print Network

    /Scintillator sandwich Fiber Detector (SFT) 2 barrels with 4 layers of scintillating fibers 2 parallel and 2 stereo SFT Particle Identification 8HERMES Recoil Detector A. Mussgiller, SPIN 2008, 10/10/08 SSDV /c : SSD & SFT & PDp ~0.6 GeV /c #12; Particle Identification (p > 0

  17. Design, spectrum measurements and simulations for a 238Pu alpha-particle irradiator for bystander effect and genomic instability experiments.

    PubMed

    Hakanen, Arvi; Siiskonen, Teemu; Pöllänen, Roy; Kosunen, Antti; Turunen, Asko; Belyakov, Oleg

    2006-08-01

    Design, spectrum measurements and simulations for an alpha-particle irradiator for bystander effect and genomic instability experiments are presented. Measured alpha-particle energy spectra were used to confirm the characteristics of the source of the irradiator specified by the manufacturer of the source. The spectra were measured in vacuum with a high-resolution spectrometer and simulated with an AASI Monte Carlo code. As a next step, we simulated alpha-particle energy spectra at the target plane of the irradiator for three different source-to-target distances. In these simulations, helium was used as the medium between the source and the exit window of the irradiator; its pressure and temperature corresponded to those of the ambient air. Mean energies and full-widths at half-maximum (FWHM) were calculated for the three different helium gas tracks. PMID:16618543

  18. Cancer Stem Cell Targeting Using the Alpha-Particle Emitter, 213Bi: Mathematical Modeling and Feasibility Analysis

    PubMed Central

    Sgouros, George; Song, Hong

    2010-01-01

    There is increasing recognition that treatment failure in cancer may be associated with the failure to sterilize a small subpopulation of tumor cells that have been characterized as tumor stem cells. Defined as cells that are able to self-renew and also to replenish a phenotypically diverse tumor-cell population, such cells are also considered resistant to chemotherapy. These characteristics are optimal for targeting by using alpha-particle-emitting radionuclides. Because of their high-energy deposition density per track, alpha-particles are capable of targeting single cells or small clusters of cells with minimal normal organ toxicity. The DNA damage induced by alpha-particles is largely irreparable and, therefore, alpha-particle-induced damage is minimally susceptible to resistance mechanisms. In this work, theoretical modeling was performed to examine the potential of alpha-emitter targeting of such small clusters of cancer stem cells. Critical parameters influencing efficacy and toxicity were identified and their relationship elucidated. The results identify specific activity, antigen site density, and number of target cells as critical parameters for effective cell killing and demonstrate substantial efficacy gains by targeting a smaller number of stem cells, as opposed to the entire tumor-cell population. PMID:18298331

  19. Study of the absorption coefficient of alpha particles to lower hybrid waves in tokamak

    NASA Astrophysics Data System (ADS)

    Wang, Jianbing; Zhang, Xianmei; Yu, Limin; Zhao, Xiang

    2014-02-01

    Part of the energy of the Lower Hybrid (LH) waves may be absorbed by the ? particles via the so-called perpendicular landau damping mechanism, which depends on various parameters of fusion reactors and the LH waves. In this article, we calculate the absorption coefficient ?? of LH waves due to ? particles. Results show that, the ?? increases with the parallel refraction index n? while deceases with increasing the frequency of LH waves ?LH over a wide range. Higher background plasma temperature and toroidal magnetic field will increase the absorption, and there is a peak value of ?? when ne?8×1019m-3 for ITER-like scenario. The thermal corrections to the cold plasma dispersion relation will change the damping rate to a certain extent under some specific conditions. We have also evaluated the fraction of LH power absorbed by the alpha particles, ? ? 0.47% and 4.1% for an LH frequency of 5 GHz and 3.7 GHz respectively for ITER-like scenario. This work gives the effective reference for the choice of parameters of future fusion reactors.

  20. Study of the absorption coefficient of alpha particles to lower hybrid waves in tokamak

    SciTech Connect

    Wang, Jianbing, E-mail: zhangxm@ecust.edu.cn; Zhang, Xianmei, E-mail: zhangxm@ecust.edu.cn; Yu, Limin, E-mail: zhangxm@ecust.edu.cn; Zhao, Xiang, E-mail: zhangxm@ecust.edu.cn [Department of Physics, East China University of Science and Technology, P.O. Box 385, Shanghai 200237 (China)

    2014-02-12

    Part of the energy of the Lower Hybrid (LH) waves may be absorbed by the ? particles via the so-called perpendicular landau damping mechanism, which depends on various parameters of fusion reactors and the LH waves. In this article, we calculate the absorption coefficient ?{sub ?} of LH waves due to ? particles. Results show that, the ?{sub ?} increases with the parallel refraction index n{sub ?} while deceases with increasing the frequency of LH waves ?{sub LH} over a wide range. Higher background plasma temperature and toroidal magnetic field will increase the absorption, and there is a peak value of ?{sub ?} when n{sub e}?8×10{sup 19}m{sup ?3} for ITER-like scenario. The thermal corrections to the cold plasma dispersion relation will change the damping rate to a certain extent under some specific conditions. We have also evaluated the fraction of LH power absorbed by the alpha particles, ? ? 0.47% and 4.1% for an LH frequency of 5 GHz and 3.7 GHz respectively for ITER-like scenario. This work gives the effective reference for the choice of parameters of future fusion reactors.

  1. An SiC\\/GaN Detector\\/Front-End Detection System for High-Resolution Alpha-Particle Spectroscopy

    Microsoft Academic Search

    A. Pullia; G. Bertuccio; D. Maiocchi; S. Caccia; F. Zocca

    2008-01-01

    An alpha-particle spectrometer has been assembled, consisting of an epitaxial 50 mum thick 4H silicon carbide (SiC) detector connected to a gallium-nitride (GaN) high-electron mobility transistor (HEMT) used as input transistor of the front-end electronics. The depleted layer of the SiC diode detector was sufficient to stop all alpha particles in the 4.8-MeV to 5.8-MeV energy range. An excellent energy

  2. An alpha particle measurement system using an energetic neutral helium beam in ITER (invited)

    SciTech Connect

    Sasao, M.; Tanaka, N.; Terai, K.; Kaneko, O. [Graduate school of Engineering, Tohoku University, Sendai 980-8579 (Japan); Kisaki, M.; Kobuchi, T.; Tsumori, K.; Okamoto, A.; Kitajima, S. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Shinto, K. [IFMIF R and D Center, Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212 (Japan); Wada, M. [Graduate School of Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)

    2012-02-15

    An energetic helium neutral beam is involved in the beam neutralization measurement system of alpha particles confined in a DT fusion plasma. A full size strong-focusing He{sup +} ion source (2 A, the beam radius of 11.3 mm, the beam energy less than 20 keV). Present strong-focusing He{sup +} ion source shows an emittance diagram separated for each beamlet of multiple apertures without phase space mixing, despite the space charge of a beamlet is asymmetric and the beam flow is non-laminar. The emittance of beamlets in the peripheral region was larger than that of center. The heat load to the plasma electrode was studied to estimate the duty factor for the ITER application.

  3. Solar flare protons and alpha particles during the last three solar cycles

    NASA Technical Reports Server (NTRS)

    Goswami, J. N.; Mcguire, R. E.; Reedy, R. C.; Lal, D.; Jha, R.

    1988-01-01

    This paper presents solar-flare-associated proton and alpha-particle fluxes determined for major events from October 1972 through March 1987 (the period that represents the last part of solar cycle 20 and the whole of solar cycle 21), using data obtained by detectors on board the IMP-7 and IMP-8 satellites, along with earlier obtained data for cycle 20. It was found that the average omnidirectional flux of protons with kinetic energy above 10 MeV for cycle 21 (64/sq cm per sec) is lower than the corresponding number for cycle 20 (92/sq cm per sec) and for the cycle 19 (378/sq cm per sec). No definitive correlation was found to exist between cycle-averaged solar flare proton fluxes and peak sunspot numbers.

  4. Study of the beta-delayed alpha-particle emission of [sup 16]N

    SciTech Connect

    Zhao, Z.; France, R.H. III; Lai, K.S.; Gai, M. (A.W. Wright Nuclear Structure Laboratory, Department of Physics, Yale University, New Haven, Connecticut 06511 (United States)); Wilds, E.L. (Department of Physics, The University of Connecticut, Storrs, Connecticut 06268 (United States)); Kryger, R.A.; Winger, J.A. (National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States)); Beard, K.B. (Department of Physics, Hampton University, Hampton, Virgina 23668 (United States))

    1993-07-01

    The beta-delayed alpha-particle emission of [sup 16]N has been studied, with [sup 16]N nuclei produced using 80 MeV/nucleon [sup 18]O beams on [sup 9]Be targets. The [sup 16]N secondary nuclei were mass analyzed and separated from the reaction products using the Michigan State University A1200 isotope separator. A detector array, including four thin surface barrier detectors, a [ital p]-[ital i]-[ital n] diode, a Ge gamma-ray detector, and a two-dimensional position sensitive parallel plate avalanche counter, was used for implantation and study of the separated nuclei. A beta-decay branching ratio of (1.3[plus minus]0.3)[times]10[sup [minus]5] to the 1[sup [minus

  5. Receiver calibration of the JET fast ion and alpha particle diagnostic

    SciTech Connect

    Machuzak, J.S.; Woskov, P.P. (MIT Plasma Fusion Center, Cambridge, Massachusetts 02139 (United States)); Bindslev, H.; Comiskey, M.; Fessey, J.; Hoekzema, J.A.; Hughes, T.P. (JET Joint Undertaking, Abingdon, Oxon OX14 3EA (United Kingdom)); Orsitto, F. (ENEA CRE Frascati (Italy))

    1992-10-01

    A collective Thomson scattering diagnostic is being implemented at JET to diagnose the velocity distribution and density of alpha particles and energetic ions. This diagnostic consists of a number of major subsystems including: a high-power 140-GHz gyrotron, a 32-channel 12-GHz bandwidth heterodyne receiver, efficient corrugated waveguide systems, variable polarizers, and in vacuum beam steering mirrors. Proper calibration of these subsystems for signal level losses, positioning, and polarization is imperative for the successful operation of the diagnostic and to facilitate the interpretation of the scattered data. A low-power Gunn oscillator was used to verify the polarization rotation induced by the seven miter bends in the receiver transmission line. The full bandwidth receiver front end losses, including the sapphire tokamak vacuum window, were initially calibrated by using the hot tokamak vessel wall as a blackbody source at approximately 310 {degree}C. Background ECE measurements will be presented.

  6. Propagation distance of the alpha-particle-induced bystander effect: the role of nuclear traversal and gap junction communication.

    PubMed

    Gaillard, Sylvain; Pusset, David; de Toledo, Sonia M; Fromm, Michel; Azzam, Edouard I

    2009-05-01

    When cell populations are exposed to low-dose alpha-particle radiation, a significant fraction of the cells will not be traversed by a radiation track. However, stressful effects occur in both irradiated and bystander cells in the population. Characterizing these effects, and investigating their underlying mechanism(s), is critical to understanding human health risks associated with exposure to alpha particles. To this end, confluent normal human fibroblast cultures were grown on polyethylene terephthalate foil grafted to an ultrathin solid-state nuclear track detector and exposed under non-perturbing conditions to low-fluence alpha particles from a broadbeam irradiator. Irradiated and affected bystander cells were localized with micrometer precision. The stress-responsive protein p21(Waf1) (also known as CDKN1A) was induced in bystander cells within a 100-microm radius from an irradiated cell. The mean propagation distance ranged from 20 to 40 microm around the intranuclear alpha-particle impact point, which corresponds to a set of approximately 30 cells. Nuclear traversal, induced DNA damage, and gap junction communication were critical contributors to propagation of this stressful effect. The strategy described here may be ideal to investigate the size of radiation-affected target and the relative contribution of different cellular organelles to bystander effects induced by energetic particles, which is relevant to radioprotection and cancer radiotherapy. PMID:19580486

  7. Mitigation of radiation nephropathy after internal {alpha}-particle irradiation of kidneys

    SciTech Connect

    Jaggi, Jaspreet Singh [Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Seshan, Surya V. [Department of Pathology, Cornell University Weill Medical College, New York, NY (United States); McDevitt, Michael R. [Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Sgouros, George [Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Hyjek, Elizabeth [Department of Pathology, Cornell University Weill Medical College, New York, NY (United States); Scheinberg, David A. [Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, NY (United States) and Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)]. E-mail: d-scheinberg@ski.mskcc.org

    2006-04-01

    Purpose: Internal irradiation of kidneys as a consequence of radioimmunotherapy, radiation accidents, or nuclear terrorism can result in radiation nephropathy. We attempted to modify pharmacologically, the functional and morphologic changes in mouse kidneys after injection with the actinium ({sup 225}Ac) nanogenerator, an in vivo generator of {alpha}- and {beta}-particle emitting elements. Methods and Materials: The animals were injected with 0.35 {mu}Ci of the {sup 225}Ac nanogenerator, which delivers a dose of 27.6 Gy to the kidneys. Then, they were randomized to receive captopril (angiotensin-converting enzyme inhibitor), L-158,809 (angiotensin II receptor-1 blocker), spironolactone (aldosterone receptor antagonist), or a placebo. Results: Forty weeks after the {sup 225}Ac injection, the placebo-control mice showed a significant increase in blood urea nitrogen (BUN) (87.6 {+-} 6.9 mg/dL), dilated Bowman spaces, and tubulolysis with basement membrane thickening. Captopril treatment accentuated the functional (BUN 119.0 {+-} 4.0 mg/dL; p <0.01 vs. placebo controls) and histopathologic damage. In contrast, L-158,809 offered moderate protection (BUN 66.6 {+-} 3.9 mg/dL; p = 0.02 vs. placebo controls). Spironolactone treatment, however, significantly prevented the development of histopathologic and functional changes (BUN 31.2 {+-} 2.5 mg/dL; p <0.001 vs. placebo controls). Conclusions: Low-dose spironolactone and, to a lesser extent, angiotensin receptor-1 blockade can offer renal protection in a mouse model of internal {alpha}-particle irradiation.

  8. Renal tubulointerstitial changes after internal irradiation with alpha-particle-emitting actinium daughters.

    PubMed

    Jaggi, Jaspreet Singh; Seshan, Surya V; McDevitt, Michael R; LaPerle, Krista; Sgouros, George; Scheinberg, David A

    2005-09-01

    The effect of external gamma irradiation on the kidneys is well described. However, the mechanisms of radiation nephropathy as a consequence of targeted radionuclide therapies are poorly understood. The functional and morphologic changes were studied chronologically (from 10 to 40 wk) in mouse kidneys after injection with an actinium-225 (225Ac) nanogenerator, a molecular-sized, antibody-targeted, in vivo generator of alpha-particle-emitting elements. Renal irradiation from free, radioactive daughters of 225Ac led to time-dependent reduction in renal function manifesting as increase in blood urea nitrogen. The histopathologic changes corresponded with the decline in renal function. Glomerular, tubular, and endothelial cell nuclear pleomorphism and focal tubular cell injury, lysis, and karyorrhexis were observed as early as 10 wk. Progressive thinning of the cortex as a result of widespread tubulolysis, collapsed tubules, glomerular crowding, decrease in glomerular cellularity, interstitial inflammation, and an elevated juxtaglomerular cell count were noted at 20 to 30 wk after treatment. By 35 to 40 wk, regeneration of simplified tubules with tubular atrophy and loss with focal, mild interstitial fibrosis had occurred. A lower juxtaglomerular cell count with focal cytoplasmic vacuolization, suggesting increased degranulation, was also observed in this period. A focal increase in tubular and interstitial cell TGF-beta1 expression starting at 20 wk, peaking at 25 wk, and later declining in intensity with mild increase in the extracellular matrix deposition was noticed. These findings suggest that internally delivered alpha-particle irradiation-induced loss of tubular epithelial cells triggers a chain of adaptive changes that result in progressive renal parenchymal damage accompanied by a loss of renal function. These findings are dissimilar to those seen after gamma or beta irradiation of kidneys. PMID:15987754

  9. Alpha-quartz-induced chemokine expression by rat lung epithelial cells: effects of in vivo and in vitro particle exposure.

    PubMed Central

    Driscoll, K. E.; Howard, B. W.; Carter, J. M.; Asquith, T.; Johnston, C.; Detilleux, P.; Kunkel, S. L.; Isfort, R. J.

    1996-01-01

    Chemokines are chemotactic cytokines that can play a key role in leukocyte recruitment to sites of tissue injury or infection. Previous studies have demonstrated that exposure to alpha-quartz as well as other noxious particles increases chemokine gene expression in rat lung, although the cells responsible for chemokine expression and the mechanisms underlying this response have remained unclear. The present studies demonstrate that exposure of rats to alpha-quartz induced expression of mRNA for the chemokine macrophage-inflammatory protein (MIP)-2 in epithelial cells lining the terminal bronchioles and alveolar ducts as well as macrophages and alveolar type II cells in the more distal lung. Treatment of rats with an anti-MIP-2 antiserum before alpha-quartz exposure markedly attenuated neutrophilic infiltration of the lungs demonstrating an important role for MIP-2 in alpha-quartz-induced pulmonary inflammation. In vitro exposure of primary cultures of rat alveolar type II cells or the rat alveolar type II cell line RLE-6TN to tumor necrosis factor-alpha, endotoxin, or alpha-quartz increased mRNA for MIP-2 as well as the structurally and functionally similar chemokine cytokine-induced neutrophil chemoattractant but not the chemokine MIP-1 alpha. The alpha-quartz-induced increase in epithelial MIP-2 mRNA resulted, at least in part, from increased gene transcription and was associated with the release of active MIP-2 protein. Induction of RLE-6TN MIP-2 and cytokine-induced neutrophil chemoattractant mRNA expression was not unique to alpha-quartz, being also increased by crocidolite asbestus fibers but not by titanium dioxide or MMVF-10 glass fibers. These findings indicate that epithelial cells contribute to chemokine expression in rat lung after exposure to alpha-quartz and potentially other noxious particles and suggest that alpha-quartz-activated MIP-2 expression in vivo results, at least in part, from a direct action of the particles on the lung epithelium. Images Figure 1 Figure 3 Figure 5 Figure 6 Figure 7 Figure 8 PMID:8909252

  10. Further insight into gravitational recoil

    SciTech Connect

    Lousto, Carlos O.; Zlochower, Yosef [Center for Computational Relativity and Gravitation, School of Mathematical Sciences, Rochester Institute of Technology, 78 Lomb Memorial Drive, Rochester, New York 14623 (United States)

    2008-02-15

    We test the accuracy of our recently proposed empirical formula to model the recoil velocity imparted to the merger remnant of spinning, unequal-mass black-hole binaries. We study three families of black-hole binary configurations, all with mass ratio q=3/8 (to nearly maximize the unequal-mass contribution to the kick) and spins aligned (or counter-aligned) with the orbital angular momentum, two with spin configurations chosen to minimize the spin-induced tangential and radial accelerations of the trajectories, respectively, and a third family where the trajectories are significantly altered by spin-orbit coupling. We find good agreement between the measured and predicted recoil velocities for the first two families, and reasonable agreement for the third. We also reexamine our original generic binary configuration that led to the discovery of extremely large spin-driven recoil velocities and inspired our empirical formula, and find rough agreement between the predicted and measured recoil speeds.

  11. Review of mathematics, numerical factors, and corrections for dark matter experiments based on elastic nuclear recoil

    Microsoft Academic Search

    J. D. Lewin; P. F. Smith

    1996-01-01

    We present a systematic derivation and discussion of the practical formulae needed to design and interpret direct searches for nuclear recoil events caused by hypothetical weakly interacting dark matter particles. Modifications to the differential energy spectrum arise from the Earth's motion, recoil detection efficiency, instrumental resolution and threshold, multiple target elements, spin-dependent and coherent factors, and nuclear form factor. We

  12. 2948 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 39, NO. 11, NOVEMBER 2011 Simulation of Alpha Particles in Rotating Plasma

    E-print Network

    throat, and these electrodes limited the rotation speed to the Alfven critical ionization velocity (CIV2948 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 39, NO. 11, NOVEMBER 2011 Simulation of Alpha Particles in Rotating Plasma Interacting With a Stationary Ripple Abraham J. Fetterman and Nathaniel J

  13. Channeling of Fusion Alpha-Particle Power Using Minority Ion Catalysis A. I. Zhmoginov and N. J. Fisch

    E-print Network

    , with electrons kept cold, so that the effective fusion reactivity can be increased [9­11]. The meansChanneling of Fusion Alpha-Particle Power Using Minority Ion Catalysis A. I. Zhmoginov and N. J greatly facilitate controlled nuclear fusion. The parameter range for achieving this temperature disparity

  14. Lower hybrid instability driven by mono-energy {alpha}-particles with finite pitch angle spread in a plasma

    SciTech Connect

    Kumar, Pawan; Singh, Vishwesh; Tripathi, V. K. [Department of Physics, IIT Delhi, New Delhi-110016 (India)

    2013-02-15

    A kinetic formalism of lower hybrid wave instability, driven by mono-energy {alpha}-particles with finite pitch angle spread, is developed. The instability arises through cyclotron resonance interaction with high cyclotron harmonics of {alpha}-particles. The {alpha}-particles produced in D-T fusion reactions have huge Larmor radii ({approx}10 cm) as compared to the wavelength of the lower hybrid wave, whereas their speed is an order of magnitude smaller than the speed of light in vacuum. As a result, large parallel phase velocity lower hybrid waves, suitable for current drive in tokamak, are driven unstable via coupling to high cyclotron harmonics. The growth rate decreases with increase in pitch angle spread of the beam. At typical electron density of {approx}10{sup 19} m{sup -3}, magnetic field {approx}4 Tesla and {alpha}-particle concentration {approx}0.1%, the large parallel phase velocity lower hybrid wave grows on the time scale of 20 ion cyclotron periods. The growth rate decreases with plasma density.

  15. Cytotoxicity of alpha-particle-emitting astatine-211-labelled antibody in tumour spheroids: no effect of hyperthermia.

    PubMed Central

    Hauck, M. L.; Larsen, R. H.; Welsh, P. C.; Zalutsky, M. R.

    1998-01-01

    The high linear energy transfer, alpha-particle-emitting radionuclide astatine-211 (211At) is of interest for certain therapeutic applications; however, because of the 55- to 70-microm path length of its alpha-particles, achieving homogeneous tracer distribution is critical. Hyperthermia may enhance the therapeutic efficacy of alpha-particle endoradiotherapy if it can improve tracer distribution. In this study, we have investigated whether hyperthermia increased the cytotoxicity of an 211At-labelled monoclonal antibody (MAb) in tumour spheroids with a radius (approximately 100 microm) greater than the range of 211At alpha-particles. Hyperthermia for 1 h at 42 degrees C was used because this treatment itself resulted in no regrowth delay. Radiolabelled chimeric MAb 81C6 reactive with the extracellular matrix antigen tenascin was added to spheroids grown from the D-247 MG human glioma cell line at activity concentrations ranging from 0.125 to 250 kBq ml(-1). A significant regrowth delay was observed at 125 and 250 kBq ml(-1) in both hyperthermia-treated and untreated spheroids. For groups receiving hyperthermia, no increase in cytotoxicity was seen compared with normothermic controls at any activity concentration. These results and those from autoradiographs indicate that hyperthermia at 42 degrees C for 1 h had no significant effect on the uptake or distribution of this antitenascin MAb in D-247 MG spheroids. Images Figure 4 Figure 5 PMID:9514054

  16. Determination of Geometry and Absorption Effects and Their Impact on the Accuracy of Alpha Particle Soft Error Rate Extrapolations

    Microsoft Academic Search

    Robert C. Baumann; Daniele Radaelli

    2007-01-01

    The results of a physical experiment and extensive simulation runs are presented for the first time demonstrating the significant effects of geometry and air absorption on accelerated alpha particle soft error rate tests. These results show that geometry and absorption must be properly accounted for even when the source is in close proximity to the device to avoid substantial underestimation

  17. Determining the impact of alpha-particle-emitting contamination from the Fukushima Daiichi disaster on Japanese manufacturing sites

    Microsoft Academic Search

    Robert C. Baumann

    2011-01-01

    We briefly review nuclear reactor operation from the point of view of the major radioactive contaminants formed and consider how these were released and dispersed into the air, water, and soil around Fukushima. The risk of contamination from alpha-particle-emitting uranium and plutonium isotopes at semiconductor manufacturing sites in Japan is considered from theoretical aspects. We report the results of low

  18. Production and evaluation of ZnS thin films by the MOCVD technique as alpha-particle detectors

    Microsoft Academic Search

    H. Kashani

    1996-01-01

    Zinc sulphide thin films are deposited on several substrates such as glass, quartz, silicon, Teflon and Mylar. The chemical reaction of hydrogen sulphide with dimethylzinc is utilised for the deposition process. The optimum working conditions (deposition rate versus flow rate, temperature and pressure) are obtained. The acquired films are characterised and the films are examined for alpha-particle sensitivity. In general,

  19. The alpha-Decay Properties of 180,182,184Pb

    Microsoft Academic Search

    K. S. Toth; J. C. Batchelder; E. F. Zganjar; C. R. Bingham; J. Wauters; C. N. Davids; D. S. Seweryniak; R. J. Irvine; L. F. Conticchio; W. B. Walters; L. T. Brown

    1996-01-01

    Targets of 90Zr, 92Zr, and 94Zr were bombarded with 92Mo ions accelerated at the Argonne National Laboratory ATLAS facility to produce 180Pb, 182Pb, and 184Pb, respectively. Recoils ejected out of the targets were passed through the ATLAS Fragment Mass Analyzer and implanted into a double-sided-strip detector for the assay of alpha-particle radioactivity. Accumulated data are being analyzed and indications are

  20. Low doses of alpha particles do not induce sister chromatid exchanges in bystander Chinese hamster cells defective in homologous recombination

    SciTech Connect

    Nagasawa, H; Wilson, P F; Chen, D J; Thompson, L H; Bedford, J S; Little, J B

    2007-10-26

    We reported previously that the homologous recombinational repair (HRR)-deficient Chinese hamster mutant cell line irs3 (deficient in the Rad51 paralog Rad51C) showed only a 50% spontaneous frequency of sister chromatid exchange (SCE) as compared to parental wild-type V79 cells. Furthermore, when irradiated with very low doses of alpha particles, SCEs were not induced in irs3 cells, as compared to a prominent bystander effect observed in V79 cells (Nagasawa et al., Radiat. Res. 164, 141-147, 2005). In the present study, we examined additional Chinese hamster cell lines deficient in the Rad51 paralogs Rad51C, Rad51D, Xrcc2, and Xrcc3 as well as another essential HRR protein, Brca2. Spontaneous SCE frequencies in non-irradiated wild-type cell lines CHO, AA8 and V79 were 0.33 SCE/chromosome, whereas two Rad51C-deficient cell lines showed only 0.16 SCE/chromosome. Spontaneous SCE frequencies in cell lines defective in Rad51D, Xrcc2, Xrcc3, and Brca2 ranged from 0.23-0.33 SCE/chromosome, 0-30% lower than wild-type cells. SCEs were induced significantly 20-50% above spontaneous levels in wild-type cells exposed to a mean dose of 1.3 mGy of alpha particles (<1% of nuclei traversed by an alpha particle). However, induction of SCEs above spontaneous levels was minimal or absent after {alpha}-particle irradiation in all of the HRR-deficient cell lines. These data suggest that Brca2 and the Rad51 paralogs contribute to DNA damage repair processes induced in bystander cells (presumably oxidative damage repair in S-phase cells) following irradiation with very low doses of alpha particles.

  1. Deceleration of Alpha Particles in the Solar Wind by Instabilities and the Rotational Force: Implications for Heating, Azimuthal Flow, and the Parker Spiral Magnetic Field

    E-print Network

    Verscharen, Daniel; Bourouaine, Sofiane; Hollweg, Joseph V

    2014-01-01

    Protons and alpha particles in the fast solar wind are only weakly collisional and exhibit a number of non-equilibrium features, including relative drifts between particle species. Two non-collisional mechanisms have been proposed for limiting differential flow between alpha particles and protons: plasma instabilities and the rotational force. Both mechanisms decelerate the alpha particles. In this paper, we derive an analytic expression for the rate $Q_{\\mathrm{flow}}$ at which energy is released by alpha-particle deceleration, accounting for azimuthal flow and conservation of total momentum. We find that $Q_{\\mathrm{flow}} > 0 $ at $r r_{\\mathrm{crit}}$. We compare the value of $Q_{\\mathrm{flow}}$ at $rUlysses spacecraft. We find that $Q_{\\mathrm{flow}}$ exceeds $Q_{\\alpha}$ at $r < 1\\,\\mathrm{AU}$, $Q_{...

  2. Search for the heaviest N ~Z alpha emitters

    NASA Astrophysics Data System (ADS)

    Grzywacz, Robert; Go, Shintaro; Nishio, Katsuhisa; Andreyev, Andrei; Rykaczewski, Krzysztof; Kolos, Karolina; Xiao, Yongchi; Jenkins, David; Orlandi, Riccardo; Hirose, Kentaro; Makii, Hiroyuki; Nishinaka, Ichiro; Ikezoe, Hiroshi; Leguillon, Romain; Otsuki, Tsutomu; Chiba, Satoshi; Heßberger, Fritz Peter

    2014-09-01

    The enhancement of an alpha-decay probability for nuclei above 100Sn is expected since valence protons and neutrons above Z = N = 50 occupy the same single-particle orbitals. The search for new alpha emitters in this region has started at JAEA Tandem Laboratory at the Advanced Science Research Center (ASRC) at Tokai, Japan. We have performed the commissioning experiments at the Recoil Mass Separator (RMS) using two reactions: 58Ni+54Fe and 58Ni+58Ni with the 58Ni beams. The data-acquisition technique developed at UTK/ORNL enabled us to identify alpha-particles and protons from the decay of 108,109Te, 109I and 113Cs, and to detect the 109Xe-105Te-101Sn decay chain. The summary of the results will be presented to demonstrate the capabilities of the ASRC's RMS.

  3. Alpha-Particle/Proton Differential Flow in the Solar Wind: Implications for Plasma Heating, Azimuthal Flow, and the Parker Spiral Magnetic Field

    NASA Astrophysics Data System (ADS)

    Verscharen, D.; Bourouaine, S.; Chandran, B. D. G.

    2014-12-01

    Protons and alpha particles in the fast solar wind are only weakly collisional and exhibit a number of non-equilibrium features, including temperature anisotropies and relative drifts along the direction of the background magnetic field. Two mechanisms have been proposed for limiting differential flow between alpha particles and protons: plasma instabilities and the rotational force. Both mechanisms decelerate the alpha particles - for example, the Alfvén/ion-cyclotron and fast-magnetosonic/whistler instabilities limit the drift velocity to a value comparable to the Alfvén speed, which decreases with increasing heliocentric distance r. However, while plasma instabilities transform bulk-flow kinetic energy into heat and plasma waves, the rotational force does not. We present an analytic expression for the rate Qflow at which energy is released when alpha particles are decelerated by instabilities. We find that Qflow becomes zero at a critical radius r=rcrit, where rcrit is between 1.5 AU and 2 AU in the fast solar wind in the ecliptic plane, and rcrit increases with increasing heliographic latitude. We show that instabilities control the deceleration of alpha particles at ralpha particles at r>rcrit. We compare the value of Qflow at ralpha particles deduced from in-situ measurements of fast-wind streams from the Helios and Ulysses spacecraft. We find that Qflow exceeds the empirical heating rate for alpha particles at r<1 AU. We conclude that the continuous energy input from alpha-particle deceleration at ralpha-particle drift for the azimuthal flow velocities of the ions and for the Parker spiral magnetic field.

  4. Schottky barrier detectors on 4H-SiC n-type epitaxial layer for alpha particles

    NASA Astrophysics Data System (ADS)

    Chaudhuri, S. K.; Krishna, R. M.; Zavalla, K. J.; Mandal, K. C.

    2013-02-01

    Schottky barrier detectors have been fabricated on 50 ?m n-type 4H-SiC epitaxial layers grown on 360 ?m SiC substrates by depositing ?10 nm nickel contact. Current-voltage (I-V) and capacitance-voltage (C-V) measurements were carried out to investigate the Schottky barrier properties. The detectors were evaluated for alpha particle detection using a 241Am alpha source. An energy resolution of ?2.7% was obtained with a reverse bias of 100 V for 5.48 MeV alpha particles. The measured charge collection efficiency (CCE) was seen to vary as a function of bias voltage following a minority carrier diffusion model. Using this model, a diffusion length of?3.5 ?m for holes was numerically calculated from the CCE vs. bias voltage plot. Rise-time measurements of digitally recorded charge pulses for the 5.48 MeV alpha particles showed a presence of two sets of events having different rise-times at a higher bias of 200 V. A biparametric correlation scheme was successfully implemented for the first time to visualize the correlated pulse-height distribution of the events with different rise-times. Using the rise-time measurements and the biparametric plots, the observed variation of energy resolution with applied bias was explained.

  5. An investigation of alpha-like particles in the DIII-D tokamak using fusion-product diagnostics

    SciTech Connect

    Duong, H.H.

    1993-01-01

    Two important issues associated with alpha physics, the single-particle behavior and the effect of collective fast-ion-driven instabilities on fast-ion confinement, have been studied in the DIII-D tokamak using fusion product diagnostics. The single-particle behavior of alpha-like tritons and [sup 3]He ions produced in deuterium-deuterium fusion reactions is studied using the d(t,n)[alpha] and d([sup 3]he,p)[alpha] fusion reactions. Fusion-produced MeV ions exhibit classical behavior in high field (B[sub T] [ge] 1.0 T) DIII-D discharges, including the new class of [open quotes]very high[close quotes] confinement plasmas. However, discharges with strong sawtooth, fishbone, or TAE activity exhibit anomalous fusion product losses. For the high field discharges without strong MHD activity, the data imply an effective diffusion coefficient smaller than [approximately]0.1 m[sup 2]/s, but in the presence of strong MHD activity, the effective diffusion of the MeV ions exceeds 1.0 m[sup 2]/s. Collective alpha particle processes are simulated by means of neutral beam injected energetic ion minorities. Toroidicity-induced Alfven Eigenmodes (TAE) are observed in DIII-D when energetic beam ions ([approximately]75 keV) are used to destabilize the mode. Measurements of the neutron emission indicate that up to 70% of the injected power is lost during strong TAE activity. Measurements of the poloidal distribution of fast-ion losses suggest that the losses are greatest near the vessel midplane. Fast-ion losses in discharges with combined fishbones and TAE bursts are 1.5 to 2 times greater than losses in fishbone discharges without TAE activity. The scaling of fast ion losses with MHD mode amplitude exhibits no threshold in the mode amplitude, suggesting that mode-particle pumping is the dominant loss mechanism.

  6. Thorium and actinium polyphosphonate compounds as bone-seeking alpha particle-emitting agents.

    PubMed

    Henriksen, Gjermund; Bruland, Oyvind S; Larsen, Roy H

    2004-01-01

    The present study explores the use of alpha-particle-emitting, bone-seeking agents as candidates for targeted radiotherapy. Actinium and thorium 1,4,7,10 tetraazacyclododecane N,N',N'',N''' 1,4,7,10-tetra(methylene) phosphonic acid (DOTMP) and thorium-diethylene triamine N,N',N'' penta(methylene) phosphonic acid (DTMP) were prepared and their biodistribution evaluated in conventional Balb/C mice at four hours after injection. All three bone-seeking agents showed a high uptake in bone and a low uptake in soft tissues. Among the soft tissue organs, only kidney had a relatively high uptake. The femur/kidney ratios for 227Th-DTMP, 228-Ac-DOTMP and 227Th-DOTMP were 14.2, 7.6 and 6.0, respectively. A higher liver uptake of 228Ac-DOTMP was seen than for 227Th-DTMP and 227Th-DOTMP. This suggests that some demetallation of the 228Ac-DOTMP complex had occurred. The results indicate that 225Ac-DOTMP, 227Th-DOTMP and 227Th-DTMP have promising properties as potential therapeutic bone-seeking agents. PMID:15015582

  7. The Alpha Particle X-Ray Spectrometer (APXS): Results from Gusev Crater and Calibration Report

    NASA Technical Reports Server (NTRS)

    Gellert, R.; Rieder, R.; Brueckner, J.; Clark, B.; Dreibus, G.; Klingelhoefer, G.; Lugmair, G.; Ming, D.; Waenke, H.; Yen, A.; Zipfel, J.; Squyres, S.

    2006-01-01

    The chemical composition of rocks and soils on Mars analyzed during the Mars Exploration Rover Spirit Mission was determined by X-ray analyses with the Alpha Particle X-Ray Spectrometer (APXS). Details of the data analysis method and the instrument calibration are presented. Measurements performed on Mars to address geometry effects and background contributions are shown. Cross calibration measurements among several instrument sensors and sources are discussed. An unintentional swap of the two flight instruments is evaluated. New concentration data acquired during the first 470 sols of rover Spirit in Gusev Crater are presented. There are two geological regions, the Gusev plains and the Columbia Hills. The plains contain soils that are very similar to previous landing sites on Mars. A meteoritic component in the soil is identified. Rocks in the plains revealed thin weathering rinds. The underlying abraded rock was classified as primitive basalt. One of these rocks contained significant Br that is probably associated with vein-filling material of different composition. One of the trenches showed large subsurface enrichments of Mg, S, and Br. Disturbed soils and rocks in the Columbia Hills revealed different elemental compositions. These rocks are significantly weathered and enriched in mobile elements, such as P, S, Cl, or Br. Even abraded rock surfaces have high Br concentrations. Thus, in contrast to the rocks and soils in the Gusev Plains, the Columbia Hills material shows more significant evidence of ancient aqueous alteration.

  8. Particle size and interfacial effects on heat transfer characteristics of water and {alpha}-SiC nanofluids.

    SciTech Connect

    Timofeeva, E.; Smith, D. S.; Yu, W.; France, D. M.; Singh, D.; Routbort, J. L. (Energy Systems); ( NE); (Univ. of Illinois)

    2010-01-01

    The effect of average particle sizes on basic macroscopic properties and heat transfer performance of {alpha}-SiC/water nanofluids was investigated. The average particle sizes, calculated from the specific surface area of nanoparticles, were varied from 16 to 90 nm. Nanofluids with larger particles of the same material and volume concentration provide higher thermal conductivity and lower viscosity increases than those with smaller particles because of the smaller solid/liquid interfacial area of larger particles. It was also demonstrated that the viscosity of water-based nanofluids can be significantly decreased by pH of the suspension independently from the thermal conductivity. Heat transfer coefficients were measured and compared to the performance of base fluids as well as to nanofluids reported in the literature. Criteria for evaluation of the heat transfer performance of nanofluids are discussed and optimum directions in nanofluid development are suggested.

  9. Effect of Differential Flow of Alpha Particles on Proton Pressure Anisotropy Instabilities in the Solar Wind

    NASA Astrophysics Data System (ADS)

    Podesta, John J.; Gary, S. Peter

    2011-11-01

    In the solar wind, when the effects of proton-proton Coulomb collisions are negligible, alpha particles usually flow faster than the protons in such a way that the differential alpha-proton flow velocity V d = V ? - V p is on the order of the Alfvén speed, is directed away from the Sun, and is nearly aligned with the local mean magnetic field. When this differential flow is taken into account, solutions of the hot plasma dispersion relation show that for the parallel propagating electromagnetic ion cyclotron (EMIC) instability driven by the proton temperature anisotropy T bottomp > T parp , the maximum growth rate occurs in the + V d direction and for the parallel firehose instability driven by the opposite proton temperature anisotropy T parp > T bottomp , the maximum growth rate occurs in the - V d direction. Thus, the EMIC instability preferentially generates left circularly polarized Alfvén-ion-cyclotron waves propagating away from the Sun and the parallel firehose instability preferentially generates right circularly polarized magnetosonic-whistler waves propagating toward the Sun with the maximum growth rates occurring for frequencies on the order of the proton cyclotron frequency and wavenumbers on the order of the proton inertial length. Because of the Doppler shift caused by the motion of the solar wind, both types of waves are left circularly polarized in the spacecraft frame for observations taken when the local mean magnetic field is collinear with the solar wind flow velocity. Theoretical investigation of these instabilities also shows that regions of parameter space exist where the unstable waves are generated propagating unidirectionally such as, for the EMIC instability for example, when the temperature anisotropy is small |(T bottomp /T parp ) - 1| < 1. Taken together, the above properties can explain the origin of parallel propagating electromagnetic waves recently observed near the proton inertial length in high-speed solar wind. The observed waves are most likely produced in situ by these instabilities. A remarkable property of the proposed mechanism that may be of practical importance is that the magnetic helicity of the unstable waves has the same sign no matter whether the proton temperature anisotropy (T pbottom/T ppar) - 1 is positive or negative.

  10. The emission probabilities of long range alpha particles from even-even 244-252Cm isotopes

    NASA Astrophysics Data System (ADS)

    Santhosh, K. P.; Krishnan, Sreejith; Priyanka, B.

    2014-10-01

    The alpha accompanied cold ternary fission of even-even 244Cm, 246Cm, 248Cm, 250Cm and 252Cm isotopes has been studied by taking the interacting barrier as the sum of the Coulomb and proximity potential with the fragments in equatorial configuration. The favorable fragment combinations are obtained from the cold reaction valley plot and by calculating the relative yield for the charge minimized fragments. In the alpha accompanied ternary fission of the 244Cm isotope, the highest yield is found for the fragment combination 110Ru+4He+130Sn, which possess near doubly magic nuclei 130Sn. For the ternary fission of 246Cm, 248Cm, 250Cm and 252Cm isotopes with 4He as the light charged particle, the highest yield is obtained for the fragment combination with doubly magic nuclei 132Sn as the heavier fragment. The emission probabilities and kinetic energies of long range alpha particles have been computed for the 242,244,246,248Cm isotopes and are found to be in good agreement with the experimental data. The relative yields for the 4He accompanied ternary fission (equatorial and collinear) of 242-252Cm isotopes are compared with the corresponding yield for binary fission. The effect of deformation and orientation of fragments in the 4He accompanied ternary fission of 244-252Cm isotopes are studied. Our study reveals that the ground state deformation has as an important role in the alpha accompanied ternary fission as that of the shell effect.

  11. The emission probabilities of long range alpha particles from even-even 244-252Cm isotopes

    E-print Network

    K. P. Santhosh; Sreejith Krishnan; B. Priyanka

    2014-09-02

    The alpha accompanied cold ternary fission of even-even 244Cm, 246Cm, 248Cm, 250Cm and 252Cm isotopes have been studied by taking the interacting barrier as the sum of Coulomb and proximity potential with the fragments in equatorial configuration. The favorable fragment combinations are obtained from the cold reaction valley plot and by calculating the relative yield for the charge minimized fragments. In the alpha accompanied ternary fission of 244Cm isotope, the highest yield is found for the fragment combination 110Ru+4He+130Sn, which possess near doubly magic nuclei 130Sn. For the ternary fission of 246Cm, 248Cm, 250Cm and 252Cm isotopes with 4He as light charged particle, the highest yield is obtained for the fragment combination with doubly magic nuclei 132Sn as the heavier fragment. The emission probabilities and kinetic energies of long range alpha particle have been computed for the 242,244,246,248Cm isotopes and are found to be in good agreement with the experimental data. The relative yields for the 4He accompanied ternary fission (equatorial and collinear) of 242-252Cm isotopes are compared with the corresponding yield for binary fission. The effect of deformation and orientation of fragments in the 4He accompanied ternary fission of 244-252Cm isotopes are studied. Our study reveals that the ground state deformation has an important role in the alpha accompanied ternary fission as that of shell effect.

  12. Determination of alpha-particle track depths in CR39 detector from their cross-sections and replica heights

    Microsoft Academic Search

    F. M. F. Ng; K. Y. Luk; D. Nikezic; K. N. Yu

    2007-01-01

    A challenging task in the application of solid-state nuclear track detectors (SSNTDs) is the measurement of depths of the tracks. One approach involves breaking and polishing the side of SSNTDs to reveal the cross-sections of the tracks for direct measurements. Recently, surface profilometry was used to measure the heights of the replicas of alpha-particle tracks to give the track depths.

  13. Study on the Sensitivity of Solid State Nuclear Track Detector (SSNTD) CR39 for Alpha-Particles Registration

    Microsoft Academic Search

    M. Gaber; A. A. Abou El-Khier; N. M. Fahmi

    1991-01-01

    The bulk etch rate, VB, in CR-39 was determined by using three methods at different etching conditions. The study was carried out for alpha-particles of energies ranging from 2.35 to 4.3 MeV at three different dissolved layers of 5.4, 7.2 and 9 ?m. Based on published REL-data, a very simple empirical formula was given to calculate REL for different ions

  14. Alpha-Particle-Driven Toroidal Alfv{acute e}n Eigenmodes in the Tokamak Fusion Test Reactor

    Microsoft Academic Search

    R. Nazikian; G. Fu; M. Bell; R. Bell; R. Budny; C. Bush; Z. Chang; Y. Chen; C. Cheng; D. Darrow; P. Efthimion; E. Fredrickson; B. Leblanc; R. Majeski; E. Mazzucato; S. Medley; J. Strachan; E. Synakowski; G. Taylor; S. Von Goeler; R. White; K. Wong; S. Zweben; S. Batha; F. Levinton; N. Gorelenkov; M. Petrov; D. Spong

    1997-01-01

    Alpha-particle-driven toroidal Alfv{acute e}n eigenmodes (TAEs) have been observed for the first time in deuterium-tritium (D-T) plasmas on the tokamak fusion test reactor (TFTR). These modes are observed 100â200ms following the end of neutral beam injection in plasmas with reduced central magnetic shear and elevated central safety factor [q(0)<1]. Mode activity is localized to the central region of the discharge

  15. Mechanism of Scintillation of Helium, Helium-Argon, and Helium-Neon Gas Mixtures Excited by Alpha Particles

    Microsoft Academic Search

    Shinzou Kubota; Tan Takahashi; Tadayoshi Doke

    1968-01-01

    An experimental investigation of the mechanism of scintillation of helium, helium-argon, and helium-neon mixtures excited by alpha particles has been performed. No detectable decrease in light yield was observed at pressures less than 3 atm when the applied electric field was increased in steps to Ep~1.0 V\\/cm Torr, where E is the electric field and p is the gas pressure.

  16. Cross sections for the production of berylium isotopes from the 880 MeV alpha-particle bombardment of carbon

    Microsoft Academic Search

    J. Lestringuez; G. M. Raisbeck; F. Yiou; R. Bernas

    1971-01-01

    The cross sections for the production of 9Be and 10Be from the 880 MeV alpha-particle bombardment of carbon have been measured to be 10.6 +\\/- 1.7 and 6.5 +\\/- 1.4 mb. These values are essentially twice the high-energy proton cross sections. It is shown that the effect of the interstellar helium on the distribution of berylium isotopes in cosmic rays

  17. Evaluation of Melt-Grown, ZnO Single Crystals for Use as Alpha-Particle Detectors

    Microsoft Academic Search

    John S. Neal; Nancy C. Giles; Xiaocheng Yang; R. Andrew Wall; K. Burak Ucer; Richard T. Williams; Dariusz J. Wisniewski; Lynn A. Boatner; Varatharajan Rengarajan; Jeff E Nause; Bill Nemeth

    2008-01-01

    As part of an ongoing investigation of the scintillation properties of zinc-oxide-(ZnO)-based scintillators, several melt-grown, ZnO single crystals have been characterized using alpha-particle excitation, infrared reflectance, and room temperature photoluminescence. The crystals, grown by Cermet, Inc., using an oxygen-pressurized melt-growth process, were doped with Group 1 elements (Li), Group 2 elements (Mg), Group 3 elements (Ga, In) and lanthanides (Gd,

  18. NOTES ON MEASUREMENTS OF $alpha$PARTICLE ACTIVITY OF SOILS, FERTILIZERS, PLANTS AND ANIMALS

    Microsoft Academic Search

    1960-01-01

    A method is described for determining total alpha activity of a sample ; and at the same time determining the relative contributions of the uranium--; radium and thorium families. Results are reported from applications of the ; method in measurements of natural alpha radioactivity of samples of soils, ; fertilizers, plants, and animal materials. (C.H.);

  19. Cytogenetic and molecular genetic analysis of tumorigenic human bronchial epithelial cells induced by radon alpha particles.

    PubMed

    Weaver, D A; Hei, T K; Hukku, B; McRaven, J A; Willey, J C

    1997-06-01

    To establish a cell culture model for lung carcinogenesis, independent populations of the human papillomavirus 18-immortalized human bronchial epithelial cell line BEP2D were treated with high linear energy transfer radon-simulated alpha-particles, expanded and xenotransplanted into Nu/Nu mice. Six independent cell lines were established from tumors that developed from three separate radiation treatments as follows: treatment (Tx) 1 (30 cGy--two doses), H2BT, Tx 2 (30 cGy--single dose), R30T1L, R30T2 and R30T3L, Tx 3 (30 cGy--single dose), H1ATN and H1ATBA1. Cytogenetic analysis revealed common changes in all tumor lines: loss of the Y chromosome (ch), one of three copies of ch8, one of three copies of ch14, and one of two copies of ch4p16-pter and ch11p15-pter. Analysis of polymerase chain reaction-amplified short tandem repeats of informative loci confirmed the loss of chY in all lines and loss of heterozygosity (LOH) at eight loci spanning the length of ch8 in all lines from Tx's 1 and 2. Our data support previous studies indicating the presence of tumor suppressor genes on ch8. LOH also was confirmed on ch14 at locus D14S306 in all cell lines from Tx 2 and in one of two lines from Tx 3. This region, 14q12-q13, may contain changes in one of the five known somatostatin receptor genes (SSTR1). No LOH was detected at any of the informative loci tested for on ch4 or ch11. PMID:9214610

  20. First measurement of the head–tail directional nuclear recoil signature at energies relevant to WIMP dark matter searches

    Microsoft Academic Search

    S. Burgos; E. Daw; J. Forbes; C. Ghag; M. Gold; C. Hagemann; V. A. Kudryavtsev; T. B. Lawson; D. Loomba; P. Majewski; D. Muna; A. St J. Murphy; G. G. Nicklin; S. M. Paling; A. Petkov; S. J. S. Plank; M. Robinson; N. Sanghi; D. P. Snowden-Ifft; N. J. C. Spooner; J. Turk; E. Tziaferi

    2009-01-01

    We present first evidence for the so-called head–tail directional signature of neutron-induced nuclear recoil tracks at energies down to 1.5keV\\/amu using the DRIFT-IIc dark matter detector. This regime is appropriate for recoils induced by Weakly Interacting Massive Particle (WIMPs) but one where the differential ionization is poorly understood. We show that the distribution of recoil energies and directions induced here

  1. Force optimized recoil control system

    NASA Astrophysics Data System (ADS)

    Townsend, P. E.; Radkiewicz, R. J.; Gartner, R. F.

    1982-05-01

    Reduction of the recoil force of high rate of fire automatic guns was proven effective. This system will allow consideration of more powerful guns for use in both helicopter and armored personnel carrier applications. By substituting the large shock loads of firing guns with a nearly constant force, both vibration and fatigue problems that prevent mounting of powerful automatic guns is eliminated.

  2. Force optimized recoil control system

    Microsoft Academic Search

    P. E. Townsend; R. J. Radkiewicz; R. F. Gartner

    1982-01-01

    Reduction of the recoil force of high rate of fire automatic guns was proven effective. This system will allow consideration of more powerful guns for use in both helicopter and armored personnel carrier applications. By substituting the large shock loads of firing guns with a nearly constant force, both vibration and fatigue problems that prevent mounting of powerful automatic guns

  3. Synchrotron-radiation experiments with recoil ions

    SciTech Connect

    Levin, J.C.

    1989-01-01

    Studies of atoms, ions and molecules with synchrotron radiation have generally focused on measurements of properties of the electrons ejected during, or after, the photoionization process. Much can also be learned, however, about the atomic or molecular relaxation process by studies of the residual ions or molecular fragments following inner-shell photoionization. Measurements are reported of mean kinetic energies of highly charged argon, krypton, and xenon recoil ions produced by vacancy cascades following inner-shell photoionization using white and monochromatic synchrotron x radiation. Energies are much lower than for the same charge-state ions produced by charged-particle impact. The results may be applicable to design of future angle-resolved ion-atom collision experiments. Photoion charge distributions are presented and compared with other measurements and calculations. Related experiments with synchrotron-radiation produced recoil ion, including photoionization of stored ions and measurement of shakeoff in near-threshold excitation, are briefly discussed. 24 refs., 6 figs., 1 tab.

  4. First measurement of the ionization yield of nuclear recoils in liquid argon

    SciTech Connect

    Joshi, T. [Univ. of California, Berkeley, CA (United States). Dept. of Nuclear Engineering; Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Sangiorgio, Samuele [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Bernstein, A. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Foxe, Michael P. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Pennsylvania State Univ., University Park, PA (United States). Dept. of Mechanical and Nuclear Engineering; Hagmann, Chris [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Jovanovic, Igor [Pennsylvania State Univ., University Park, PA (United States). Dept. of Mechanical and Nuclear Engineering; Kazkaz, K. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Mozin, Vladimir V. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Norman, E. B. [Univ. of California, Berkeley, CA (United States). Dept. of Nuclear Engineering; Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Pereverzev, S. V. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Rebassoo, Finn O. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Sorensen, Peter F. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

    2014-05-01

    Liquid phase argon has long been used as a target medium for particle detection via scintillation light. Recently there has been considerable interest in direct detection of both hypothetical darkmatter particles and coherent elastic neutrino nucleus scattering. These as-yet unobserved neutral particle interactions are expected to result in a recoiling argon atom O(keV), generally referred to in the literature as a nuclear recoil. This prompts the question of the available electromagnetic signal in a liquid argon detector. In this Letter we report the first measurement of the ionization yield (Qy), detected electrons per unit energy, resulting from nuclear recoils in liquid argon, measured at 6.7 keV. This is also the lowest energy measurement of nuclear recoils in liquid argon.

  5. Improve the catalytic activity of {alpha}-Fe{sub 2}O{sub 3} particles in decomposition of ammonium perchlorate by coating amorphous carbon on their surface

    SciTech Connect

    Zhang Yifu [Engineering Research Center of Organosilicon Compound and Material, Ministry of Education of China, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Liu Xinghai, E-mail: liuxh@whu.edu.c [School of Printing and Packaging, Wuhan University, Wuhan 430079 (China); Nie Jiaorong [Jianghe Chemical Factory of CSSG, Yuan'an 444200 (China); Yu Lei; Zhong Yalan [Engineering Research Center of Organosilicon Compound and Material, Ministry of Education of China, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Huang Chi, E-mail: chihuang@whu.edu.c [Engineering Research Center of Organosilicon Compound and Material, Ministry of Education of China, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China)

    2011-02-15

    Sphere- and pod-like {alpha}-Fe{sub 2}O{sub 3} particles have been selectively synthesized using NH{sub 3}.H{sub 2}O and NaOH solution to adjust the pH value of the designed synthetic system, respectively. The sphere-like {alpha}-Fe{sub 2}O{sub 3} particles with diameter about 25 nm on average were encapsulated into carbon shells to fabricate a novel core-shell composite ({alpha}-Fe{sub 2}O{sub 3}-C) through the coating experiments. The catalytic performance of the products on the thermal decomposition of ammonium perchlorate (AP) was investigated by thermal gravimetric analyzer (TG) and differential thermal analysis (DTA). The thermal decomposition temperatures of AP in the presence of pod-like {alpha}-Fe{sub 2}O{sub 3}, sphere-like {alpha}-Fe{sub 2}O{sub 3} and {alpha}-Fe{sub 2}O{sub 3}-C are reduced by 72, 81 and 109 {sup o}C, respectively, which show that {alpha}-Fe{sub 2}O{sub 3}-C core-shell composites have higher catalytic activity than that of {alpha}-Fe{sub 2}O{sub 3}. -- Graphical abstract: The catalytic performance of pod-like {alpha}-Fe{sub 2}O{sub 3}, sphere-like {alpha}-Fe{sub 2}O{sub 3} and {alpha}-Fe{sub 2}O{sub 3}-C on the thermal decomposition of ammonium perchlorate (AP). Display Omitted Research highlights: {yields} Sphere- and pod-like {alpha}-Fe{sub 2}O{sub 3} particles have been selectively synthesized using NH{sub 3}.H{sub 2}O and NaOH solution to adjust the pH value. {yields} A novel core-shell composite ({alpha}-Fe{sub 2}O{sub 3}-C core-shell structured composite) has been successfully synthesized using sphere-like {alpha}-Fe{sub 2}O{sub 3} particles as the cores and glucose as the source of carbon. {yields} The thermal decomposition temperatures of AP in the presence of pod-like {alpha}-Fe{sub 2}O{sub 3}, sphere-like {alpha}-Fe{sub 2}O{sub 3} and {alpha}-Fe{sub 2}O{sub 3}-C are reduced by 72, 81 and 109 {sup o}C, respectively, which shows that these materials have high catalytic activity.

  6. The $\\alpha-\\alpha$ fishbone potential revisited

    E-print Network

    Day, J P; Elhanafy, M; Smith, E; Woodhouse, R; Papp, Z

    2011-01-01

    The fishbone potential of composite particles simulates the Pauli effect by nonlocal terms. We determine the $\\alpha-\\alpha$ fishbone potential by simultaneously fitting to two-$\\alpha$ resonance energies, experimental phase shifts and three-$\\alpha$ binding energies. We found that essentially a simple gaussian can provide a good description of two-$\\alpha$ and three-$\\alpha$ experimental data without invoking three-body potentials.

  7. The Radiation Chemistry of Aqueous Solutions. I. The Effect of Changing Linear Energy Transfer Along a Polonium alpha-Particle Track

    Microsoft Academic Search

    E. Collinson; F. S. Dainton; J. Kroh

    1962-01-01

    Absolute G values for chemical change when various aqueous solutions are irradiated with alpha-particles from an external polonium source have been determined for different fractions (x) of the alpha-particle track spent within the solution. G(Fe3+) for an aerated solution containing 1 mM ferrous ions and 0\\\\cdot1 N sulphuric acid decreases from 5\\\\cdot0 at x = 0\\\\cdot02 through a minimum value

  8. High-resolution alpha-particle spectroscopy with an hybrid SiC\\/GaN detector\\/front-end detection system

    Microsoft Academic Search

    A. Pullia; G. Bertuccio; D. Maiocchi; S. Caccia; F. Zocca

    2007-01-01

    An alpha-particle spectrometer has been assembled, consisting of an epitaxial 50 mum thick 4H silicon carbide detector connected to a gallium nitride HEMT used as input transistor of the front-end electronics. The depleted layer of the SiC diode detector was sufficient to stop all alpha particles of the used emitter in the 4.8-MeV to 5.8-MeV energy range. An excellent energy

  9. Selective gene amplification in mammalian cells after exposure to 60Co gamma rays, 241Am alpha particles, or uv light

    SciTech Connect

    Luecke-Huhle, C.P.; Pech, M.; Herrlich, P.

    1986-06-01

    Simian Virus 40 wild type (SV40)-transformed Chinese hamster embryo cells (Co631) contain about five viral copies integrated per cell genome. These SV40 sequences were used as endogenous indicator genes to study the response of mammalian cells to radiation at the gene level. An increase in copy number was detected by dispersed cell blotting and Southern analysis in combination with specific DNA hybridization. All types of radiation tested induce a 15- to 25-fold amplification of SV40 sequences without producing intact virus. The amplification is dose dependent and increases with time after irradiation: a maximum effect is observed at Day 3 after alpha particle or uv exposure and at Day 6 after gamma-ray exposure. A RBE of 6 can be calculated for alpha particles if amplification rates at Day 3 are compared. However, when the maximum effect is considered independent of time, no difference between different types of radiation is observed. Southern blots of genomic DNA show that not all integrated SV40 sequences are amplified upon radiation. Amplified sequences are found either in restriction fragments of relatively high molecular weight or in unit size fragments. SV40 amplification is selective in that the amplification of other genes, e.g., of alpha-actin, dhfr (dihydrofolate reductase), and of two oncogenes of the ras family (Kirsten ras and Harvey ras), was below detection level.

  10. Alpha-particle-induced luminescence of rare-earth-doped Y{sub 2}O{sub 3} nanophosphors

    SciTech Connect

    Cress, Cory D. [NanoPower Research Laboratories at the Rochester Institute of Technology, 85 Lomb Memorial Road, Rochester, NY 14623 (United States); Microsystems Engineering Program at the Rochester Institute of Technology, Rochester, NY 14623 (United States)], E-mail: cory_cress@hotmail.com; Redino, Christopher S. [NanoPower Research Laboratories at the Rochester Institute of Technology, 85 Lomb Memorial Road, Rochester, NY 14623 (United States)], E-mail: csr8932@rit.edu; Landi, Brian J. [NanoPower Research Laboratories at the Rochester Institute of Technology, 85 Lomb Memorial Road, Rochester, NY 14623 (United States)], E-mail: bjlsps@rit.edu; Raffaelle, Ryne P. [NanoPower Research Laboratories at the Rochester Institute of Technology, 85 Lomb Memorial Road, Rochester, NY 14623 (United States); Microsystems Engineering Program at the Rochester Institute of Technology, Rochester, NY 14623 (United States)], E-mail: rprsps@rit.edu

    2008-08-15

    The feasibility of utilizing Y{sub 2}O{sub 3}:Tb{sup 3+} and Y{sub 2}O{sub 3}:Eu{sup 3+} as radioluminescent nanophosphors under alpha-particle excitation is investigated. Materials synthesized by the urea homogeneous precipitation method were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The XRD analysis of as-produced precipitates and nanophosphors fired at temperatures ranging from 950 to 1100 deg. C indicated the presence of highly crystalline cubic Y{sub 2}O{sub 3} with crystallite sizes of {approx}40 nm. SEM and TEM analysis revealed that particles with average diameters of {approx}200 nm and comprised of {approx}40 nm grains were obtained. High-resolution radioluminescence and photoluminescence spectra were used to investigate the unwanted radioluminescence saturation effects associated with the high ionization rate of alpha-particles. Additionally, the radioluminescence intensity as a function of rare-earth ion dopant concentration is investigated for these materials under alpha-particle excitation. The prospect for utilizing these materials as intermediate absorbers in indirect-conversion radioisotope batteries is discussed. - Graphical abstract: The photoluminescence and radioluminesce emission from rare-earth doped Y{sub 2}O{sub 3} nanophosphors are being investigated. Below is a representative image of the photoluminescence from Y{sub 2}O{sub 3}:Eu{sup 3+} (left) and Y{sub 2}O{sub 3}:Tb{sup 3+} (right) under UV-light excitation.

  11. Production of TNF-alpha and bone resorbing activity by macrophages in response to different types of bone cement particles.

    PubMed

    Ingham, E; Green, T R; Stone, M H; Kowalski, R; Watkins, N; Fisher, J

    2000-05-01

    We have compared the capacity of clinically relevant wear debris from seven different cement types to activate macrophages to produce TNF-alpha, IL-1beta, IL-6 and bone resorbing activity in vitro. The bone cements were: CMW 1 original (PMMA only); CMW 1RO (1 microm BaSO4; 9.2%); CMW copolymer bone cement 1 (10 microm BaSO4; 10%); CMW copolymer bone cement 2 (1 microm BaSO4; 10%); Palacos R (10 microm ZrO2; 15.6%); CMW Calcium phosphate cement 20% (10 microm tri-calcium phosphate; 20%) and CMW calcium phosphate cement 30% (10 microm tri-calcium phosphate; 30%). Cement debris was produced aseptically using a simple configuration wear test. The majority of particles were in the size range 0.1-0.5 microm for each cement type. The cement particles were co-cultured with the U937 macrophage cell line at ratios of 10 and 100 microm3 particle volumes to macrophage cell numbers for 24 h. At the 10:1 ratio the particles had no effect on the cells. At the 100:1 ratio, the major cytokine produced was TNF-alpha and there were no statistical differences between the different types of cement debris. The bone resorption activity of the co-culture supernatants was significantly greater than the control (U937 cells without particles) for particles of CMW 1RO, CMW copolymer bone cement 1, CMW copolymer bone cement 2 and Palacos R (P < 0.05, ANOVA). However there were no statistical differences between the levels of bone resoprtion evoked by these four cement types. The CMW1 original and CMW calcium phosphate containing cements failed to induce the macrophages to elaborate bone resorption activity at the 100:1 ratio. These data suggest that the addition of radio-opaque additives to bone cement may increase the capacity of the debris to induce osteolysis. PMID:10768752

  12. Effect of composition and radiation on the Hertzian indentation behavior of nuclear waste glasses. [77-MeV alpha particles

    SciTech Connect

    Matzke, H.; Kahl, L.; Routbort, J.L.; Saidl, J.

    1983-01-01

    The Hertzian indentation technique has been used to determine the fracture toughness, K/sub Ic/ of two borosilicate glasses developed to contain high-level nuclear waste. For the product VG 98/12, adding selected groups of fission products leaves K/sub Ic/ unchanged, but addition of Pb lowers K/sub Ic/ by approx. 20%. Radiation with 77 MeV ..cap alpha..-particles to a dose of approx. 10/sup 15/ ..cap alpha../cm/sup 2/ increases K/sub Ic/ by approx. 75%. For the product SM 58 LW 11, the fracture toughness was measured on pieces taken from different parts of a large cylinder to investigate the effects of segregation phenomena and of partial crystallization and formation of small cristobalite inclusions which decrease K/sub Ic/ by approx. 25%.

  13. Fabrication, testing and simulation of a high spatial resolution alpha-particle imager based on ZnO nanowires in a polycarbonate nanoporous membrane

    NASA Astrophysics Data System (ADS)

    Taheri, Ali; Saramad, Shahyar; Ghalenoi, Samira; Setayeshi, Saeed

    2013-12-01

    A new architecture consisting of ZnO nanowires embedded in a polycarbonate nanoporous membrane was proposed, fabricated and simulated as a high spatial resolution alpha particle imager. The experimental and Geant4 simulation results showed that ZnO nanowires could act as scintillating fibers to prevent spread of the generated optical photons inside the imager. This property can be used to precisely determine alpha collision coordinates. An array of these nanowires can be also applied as a new high spatial resolution alpha particle imager.

  14. Interference, recoil, and uncontrollable interaction

    NASA Astrophysics Data System (ADS)

    Ulfbeck, Ole

    2014-07-01

    When the initial state in a collision involves indeterminate momenta, the conservation law for momentum no longer applies to the individual event with a sharpness beyond the indeterminacy. As a consequence, there are collisions that are recoilless in the sense that the state of one of the quanta is unchanged by the collision while the other quantum emerges in a superposition of momenta. Recoilless collisions that avoid entanglement are basic for experiments studying coherence effects for individual quanta involving interactions of the quantum with reflectors or diaphragms. The idea that in interference experiments there is an inevitable recoil that can be made unobservable by firmly bolting the reflector or diaphragm to a solid support is false since in interference with individual quanta there is no recoil to control. The highly quantal character of the reflector or diaphragm in the interference experiment apparently went unnoticed in the conception of complementarity.

  15. Radioimmunotherapy of Breast Cancer Metastases with Alpha-Particle-emitter 225Ac: Comparing Efficacy with 213Bi, 90Y

    PubMed Central

    Song, Hong; Hobbs, Robert F.; Vajravelu, Ravy; Huso, David L.; Esaias, Caroline; Apostolidis, Christos; Morgenstern, Alfred; Sgouros, George

    2009-01-01

    Alpha-particles are suitable to treat cancer micrometastases because of their short range and very high linear energy transfer. Alpha-particle-emitter 213Bi based radioimmunotherapy has shown efficacy in a variety of metastatic animal cancer models, such as breast, ovarian, prostate cancer and leukemia. Its clinical implementation, however, is challenging due to the limited supply of 225Ac, the high technical requirement to prepare radioimmunoconjugate with very short half-life (T1/2=45.6 mins) on site and prohibitive cost. In this study, we investigated the efficacy of the alpha-particle-emitter 225Ac, parent of 213Bi, in a mouse model of breast cancer metastases. A single administration of 225Ac (400 nCi) labeled anti-rat HER-2/neu monoclonal antibody (7.16.4) completely eradicated breast cancer lung micrometastases in about 67% of HER-2/neu transgenic mice and led to long-term survival of these mice for up to one year. Treatment with 225Ac-7.16.4 is significantly more effective than 213Bi-7.16.4 (120 ?Ci) (median survival = 61 days, P=0.001), and 90Y-7.16.4 (120 ?Ci) (median survival = 50 days, P<0.001), as well as untreated control (median survival = 41 days, P=0.0001). Dosimetric analysis showed that 225Ac treated metastases received a total dose of 9.6 Gy, significantly higher than 2.0 Gy from 213Bi and 2.4 Gy from 90Y. Biodistribution studies revealed that 225Ac daughters, 221Fr and 213Bi, accumulated in kidneys and probably contributed to the long-term renal toxicity observed in surviving mice. These data suggest 225Ac labeled anti-HER-2/neu monoclonal antibody could significantly prolong survival in HER-2/neu-positive metastatic breast cancer patients. PMID:19920193

  16. Radioimmunotherapy of breast cancer metastases with alpha-particle emitter 225Ac: comparing efficacy with 213Bi and 90Y.

    PubMed

    Song, Hong; Hobbs, Robert F; Vajravelu, Ravy; Huso, David L; Esaias, Caroline; Apostolidis, Christos; Morgenstern, Alfred; Sgouros, George

    2009-12-01

    alpha-Particles are suitable to treat cancer micrometastases because of their short range and very high linear energy transfer. alpha-Particle emitter (213)Bi-based radioimmunotherapy has shown efficacy in a variety of metastatic animal cancer models, such as breast, ovarian, and prostate cancers. Its clinical implementation, however, is challenging due to the limited supply of (225)Ac, high technical requirement to prepare radioimmunoconjugate with very short half-life (T(1/2) = 45.6 min) on site, and prohibitive cost. In this study, we investigated the efficacy of the alpha-particle emitter (225)Ac, parent of (213)Bi, in a mouse model of breast cancer metastases. A single administration of (225)Ac (400 nCi)-labeled anti-rat HER-2/neu monoclonal antibody (7.16.4) completely eradicated breast cancer lung micrometastases in approximately 67% of HER-2/neu transgenic mice and led to long-term survival of these mice for up to 1 year. Treatment with (225)Ac-7.16.4 is significantly more effective than (213)Bi-7.16.4 (120 microCi; median survival, 61 days; P = 0.001) and (90)Y-7.16.4 (120 microCi; median survival, 50 days; P < 0.001) as well as untreated control (median survival, 41 days; P < 0.0001). Dosimetric analysis showed that (225)Ac-treated metastases received a total dose of 9.6 Gy, significantly higher than 2.0 Gy from (213)Bi and 2.4 Gy from (90)Y. Biodistribution studies revealed that (225)Ac daughters, (221)Fr and (213)Bi, accumulated in kidneys and probably contributed to the long-term renal toxicity observed in surviving mice. These data suggest (225)Ac-labeled anti-HER-2/neu monoclonal antibody could significantly prolong survival in HER-2/neu-positive metastatic breast cancer patients. PMID:19920193

  17. The role of nuclear reactions and {alpha}-particle transport in the dynamics of inertial confinement fusion capsules

    SciTech Connect

    Garnier, Josselin [Laboratoire de Probabilites et Modeles Aleatoires and Laboratoire Jacques-Louis Lions, Universite Paris VII, 2 Place Jussieu, 75251 Paris Cedex 05 (France); Cherfils-Clerouin, Catherine [Commissariat a l'Energie Atomique, Direction des Applications Militaires, Boite Postale 12, 91680 Bruyeres le Chatel (France)

    2008-10-15

    This paper is devoted to the study of the deceleration phase of inertial confinement capsules. The purpose is to obtain a zero-dimensional model that has the form of a closed system of ordinary differential equations for the main hydrodynamic quantities. The model takes into account the energy released by nuclear reactions, a nonlocal model for the {alpha}-particle energy deposition process, and radiation loss by electron bremsstrahlung. The asymptotic analysis is performed in the case of a strong temperature dependence of the thermal conductivity. We finally study the beginning of the expansion phase after stagnation to derive an ignition criterion.

  18. Development of a He- and He0 beam source for alpha particle measurement in a burning plasma.

    PubMed

    Tanaka, N; Sasao, M; Terai, K; Okamoto, A; Kitajima, S; Yamaoka, H; Wada, M

    2012-02-01

    Proof of principle experiments of neutral helium beam production for alpha particle diagnostics was carried out on a test stand. Negative helium ions were produced in the Li charge exchange cell, in which stable and long time operation was possible. He(-) beam was accelerated to 157 keV. Finally, He(0) beam was successfully produced after the flight in the drift-tube through the auto-electron-detachment process from He(-) to He(0). A neutral beam detector using a pyroelectric device was also developed to measure He(0) beam intensity. The metastable component in the neutral helium beam was found to be less than 2%. PMID:22380272

  19. 1.5D Quasilinear Model for Alpha Particle-TAE Interaction in ARIES ACT-I

    SciTech Connect

    K. Ghantous, N.N. Gorelenkov, C. Kessel, F. Poli

    2013-01-30

    We study the TAE interaction with alpha particle fusion products in ARIES ACT-I using the 1.5D quasilinear model. 1.5D uses linear analytic expressions for growth and damping rates of TAE modes evaluated using TRANSP pro les to calculates the relaxation of pressure pro les. NOVA- K simulations are conducted to validate the analytic dependancies of the rates, and to normalize their absolute value. The low dimensionality of the model permits calculating loss diagrams in large parameter spaces.

  20. PPPL3164 Preprint Date: January 1996, UC420 Alpha Particle Losses from Tokamak Fusion Test Reactor

    E-print Network

    Reactor Deuterium­Tritium Plasmas D. S. Darrow, S. J. Zweben, S. Batha*, R. V. Budny, C. E. Bush + , Z. A. Spong + , E. J. Strait # , G. Taylor, R. B. White, J. R. Wilson, K.­L. Wong, and M. C. Zarnstorff can have a significant influence on tokamak reactor viability, the loss of deuterium­tritium alpha

  1. Nickel-59 in Surface Layers of Lunar Basalt 74275: Implications for the Solar Alpha Particle Flux

    NASA Technical Reports Server (NTRS)

    Schnabel, C.; Xue, S.; Ma, P.; Herzog, G. F.; Fifield, K.; Cresswell, R. G.; diTada, M. L.; Hausladen, Paul; Reedy, R. C.

    2000-01-01

    By using AMS we have profiled 59 Ni/Ni ratios in lunar basalt 74275. Activities (dpm 59 Ni/[kg Fe]) range from 120 to 10 at depths (mg/cm 2) from about 30 to 650. Modeling results hint at higher solar alpha fluxes during the last about 0.5 My than during the last approximately 1 My.

  2. TF Ripple Loss of Alpha Particles from the ITER Interim Design: Simulation and Theory

    E-print Network

    the normalization of a simple model for stochastic ripple losses within the TRANSP code [6]. Collisions were found without collisional eects. Good agree- ment was found in comparing appropriately normalized TRANSP in the ITER database. TRANSP simulations of ITER also provided alpha source pro#12;les, before and after

  3. TF Ripple Loss of Alpha Particles from the ITER Interim Design: Simulation and Theory

    E-print Network

    the normalization of a simple model for stochastic ripple losses within the TRANSP code [6]. Collisions were found without collisional effects. Good agree­ ment was found in comparing appropriately normalized TRANSP database. TRANSP simulations of ITER also provided alpha source profiles, before and after sawtooth

  4. Very High Efficiency, Miniaturized, Long-Lived Alpha Particle Power Source Using Diamond Devices for Extreme Space Environments

    NASA Technical Reports Server (NTRS)

    Kolawa, Elizabeth A. (Inventor); Patel, Jagdishbhai U. (Inventor); Fleurial, Jean-Pierre (Inventor)

    2004-01-01

    A power source that converts a-particle energy into electricity by coulomb collision in doped diamond films is described. Alpha particle decay from curium-244 creates electron-hole pairs by free- ing electrons and holes inside the crystal lattice in N- and P-doped diamond films. Ohmic contacts provide electrical connection to an electronic device. Due to the built-in electric field at the rectifying junction across the hT- and P-doped diamond films, the free electrons are constrained to traveling in generally one direction. This one direction then supplies electrons in a manner similar to that of a battery. The radioactive curium layer may be disposed on diamond films for even distribution of a-particle radiation. The resulting power source may be mounted on a diamond substrate that serves to insulate structures below the diamond substrate from a-particle emission. Additional insulation or isolation may be provided in order to prevent damage from a-particle collision. N-doped silicon may be used instead of N-doped diamond.

  5. Deceleration of Alpha Particles in the Solar Wind by Instabilities and the Rotational Force: Implications for Heating, Azimuthal Flow, and the Parker Spiral Magnetic Field

    NASA Astrophysics Data System (ADS)

    Verscharen, Daniel; Chandran, Benjamin D. G.; Bourouaine, Sofiane; Hollweg, Joseph V.

    2015-06-01

    Protons and alpha particles in the fast solar wind are only weakly collisional and exhibit a number of non-equilibrium features, including relative drifts between particle species. Two non-collisional mechanisms have been proposed for limiting differential flow between alpha particles and protons: plasma instabilities and the rotational force. Both mechanisms decelerate the alpha particles. In this paper, we derive an analytic expression for the rate {Q}{flow} at which energy is released by alpha-particle deceleration, accounting for azimuthal flow and conservation of total momentum. We show that instabilities control the deceleration of alpha particles at r\\lt {r}{crit}, and the rotational force controls the deceleration of alpha particles at r\\gt {r}{crit}, where {r}{crit}? 2.5 {AU} in the fast solar wind in the ecliptic plane. We find that {Q}{flow} is positive at r\\lt {r}{crit} and {Q}{flow}=0 at r?slant {r}{crit}, consistent with the previous finding that the rotational force does not lead to a release of energy. We compare the value of {Q}{flow} at r\\lt {r}{crit} with empirical heating rates for protons and alpha particles, denoted {Q}p and {Q}? , deduced from in situ measurements of fast-wind streams from the Helios and Ulysses spacecraft. We find that {Q}{flow} exceeds {Q}? at r\\lt 1 {AU}, and that {Q}{flow}/{Q}p decreases with increasing distance from the Sun from a value of about one at r = 0.29–0.42 AU to about 1/4 at 1 AU. We conclude that the continuous energy input from alpha-particle deceleration at r\\lt {r}{crit} makes an important contribution to the heating of the fast solar wind. We also discuss the implications of the alpha-particle drift for the azimuthal flow velocities of the ions and for the Parker spiral magnetic field.

  6. FISSION FRAGMENT RECOIL EFFECTS ON ZIRCONIUM OXIDATION

    Microsoft Academic Search

    W. C. Yee; G. H. Jenks; E. E. Stansbury

    1962-01-01

    Fission fragment recoil effects on zirconium oxidation in pure oxygen ; were studied at 1 atm pressure and 250 deg C. Specimens were oxidized under the ; following conditions: reactor radiations including recoils, reactor radiations in ; the absence of recoils, and no radiation. Irradiation experiments were conducted ; in a maximum thermal neutron flux of 8.5 x 10¹¹ neutrons\\/cm²-sec.

  7. Gene amplification and microsatellite instability induced in tumorigenic human bronchial epithelial cells by alpha particles and heavy ions

    NASA Technical Reports Server (NTRS)

    Piao, C. Q.; Hei, T. K.; Hall, E. J. (Principal Investigator)

    2001-01-01

    Gene amplification and microsatellite alteration are useful markers of genomic instability in tumor and transformed cell lines. It has been suggested that genomic instability contributes to the progression of tumorigenesis by accumulating genetic changes. In this study, amplification of the carbamyl-P-synthetase, aspartate transcarbamylase, dihydro-orotase (CAD) gene in transformed and tumorigenic human bronchial epithelial (BEP2D) cells induced by either alpha particles or (56)Fe ions was assessed by measuring resistance to N-(phosphonacetyl)-l-aspartate (PALA). In addition, alterations of microsatellite loci located on chromosomes 3p and 18q were analyzed in a series of primary and secondary tumor cell lines generated in nude mice. The frequency of PALA-resistant colonies was 1-3 x 10(-3) in tumor cell lines, 5-8 x 10(-5) in transformed cells prior to inoculation into nude mice, and less than 10(-7) in control BEP2D cells. Microsatellite alterations were detected in all 11 tumor cell lines examined at the following loci: D18S34, D18S363, D18S877, D3S1038 and D3S1607. No significant difference in either PALA resistance or microsatellite instability was found in tumor cell lines that were induced by alpha particles compared to those induced by (56)Fe ions.

  8. High resolution alpha particle detection using 4H-SiC epitaxial layers: Fabrication, characterization, and noise analysis

    NASA Astrophysics Data System (ADS)

    Chaudhuri, Sandeep K.; Zavalla, Kelvin J.; Mandal, Krishna C.

    2013-11-01

    In this article we report the fabrication and characterization of large area, room-temperature operable and very high resolution Schottky barrier detectors for alpha particles using 20 ?m thick n-type 4H-SiC epitaxial layers. Schottky barriers were fabricated by depositing circular nickel contacts of ~11 mm2 area on the 4H-SiC epitaxial layers. Room temperature current-voltage measurements revealed very high Schottky barrier height of 1.6 eV and extremely low leakage current of 3.5 pA at an operating reverse bias of -90 V. We also report an energy resolution of 0.29%, which is the best resolution obtained so far for uncollimated 5.48 MeV alpha particles in 4H-SiC epitaxial detectors with such a large area. Very low micropipe density (<1 cm-2) and low effective doping concentration (2.4×1014 cm-3) in the epilayer helped to achieve a high resolution even with the large detector area and a broad source. A diffusion length of ~18.6 ?m for holes has been determined in these detectors following a calculation based on a drift-diffusion model. A noise analysis in terms of equivalent noise charge revealed that the white series noise due to the detector capacitance has substantial effect on their spectroscopic performance.

  9. Screening materials with the XIA UltraLo alpha particle counter at Southern Methodist University

    SciTech Connect

    Nakib, M. Z.; Cooley, J.; Kara, B.; Qiu, H.; Scorza, S. [Department of Physics, Southern Methodist University, Dallas, TX (United States)] [Department of Physics, Southern Methodist University, Dallas, TX (United States); Guiseppe, V. E. [Department of Physics, University of South Dakota, Vermillion, SD (United States)] [Department of Physics, University of South Dakota, Vermillion, SD (United States); Rielage, K. [Los Alamos National Laboratory, Los Alamos, NM (United States)] [Los Alamos National Laboratory, Los Alamos, NM (United States); Schnee, R. W. [Department of Physics, Syracuse University, Syracuse, NY (United States)] [Department of Physics, Syracuse University, Syracuse, NY (United States)

    2013-08-08

    Southern Methodist University houses one of five existing commercially available UltraLo 1800 production model alpha counters made by XIA LLC. The instrument has an electron drift chamber with a 707 cm{sup 2} or 1800 cm{sup 2} counting region which is determined by selecting the inner electrode size. The SMU team operating this device is part of the SuperCDMS screening working group, and uses the alpha counter to study the background rates from the decay of radon in materials used to construct the SuperCDMS experiment. We have studied four acrylic samples obtained from the MiniCLEAN direct dark matter search with the XIA instrument demonstrating its utility in low background experiments by investigating the plate-out of {sup 210}Pb and comparing the effectiveness of cleaning procedures in removing {sup 222}Rn progenies from the samples.

  10. Substate Populations and Nuclear Polarization Produced by Inelastic Alpha-Particle Scattering on Carbon12

    Microsoft Academic Search

    T. D. Hayward; F. H. Schmidt

    1970-01-01

    We have measured the normalized alpha-gamma angular correlation in the reaction plane for excitation of the 4.44-MeV, 2+ state of 12C at 22.750 MeV. These data yield the relative populations (am)2 of the three magnetic substates referred to the normal to the reaction plane. The ambiguity between (a+2)2 and (a-2)2 was resolved by coincidence measurements of the circular polarization of

  11. Recommended Energy and Intensity Values of Alpha Particles from Radioactive Decay

    Microsoft Academic Search

    A. Rytz

    1991-01-01

    The present compilation in the third revised version of a collection of selected α-particle data found in the literature. It includes 516 values from 286 α-particle emitters, corresponding to an increase of 12% and 17%, respectively, over the 1979 version. The weighted means form a consistent set of recommended energy and branching values.

  12. Alpha track analysis and fission track analysis for localizing actinide-bearing micro-particles in the Yenisey River bottom sediments

    Microsoft Academic Search

    I. E. Vlasova; St. N. Kalmykov; Yu. V. Konevnik; S. G. Simakin; I. S. Simakin; A. Yu. Anokhin; Yu. A. Sapozhnikov

    2008-01-01

    Distribution of actinides in bottom sediment and flood land soil cores collected from the Yenisey River near the Krasnoyarsk Mining and Chemical Combine (MCC) were analyzed. Actinide-bearing micro-particles were localized using alpha track analysis (ATA) and fission track analysis (FTA). Different types of radioactive micro-particles were found by analysis of the ratios of fission tracks to ?-tracks from single particles.

  13. Single particle tracking of alpha7 nicotinic AChR in hippocampal neurons reveals regulated confinement at glutamatergic and GABAergic perisynaptic sites.

    PubMed

    Bürli, Thomas; Baer, Kristin; Ewers, Helge; Sidler, Corinne; Fuhrer, Christian; Fritschy, Jean-Marc

    2010-01-01

    Alpha7 neuronal nicotinic acetylcholine receptors (alpha7-nAChR) form Ca(2+)-permeable homopentameric channels modulating cortical network activity and cognitive processing. They are located pre- and postsynaptically and are highly abundant in hippocampal GABAergic interneurons. It is unclear how alpha7-nAChRs are positioned in specific membrane microdomains, particularly in cultured neurons which are devoid of cholinergic synapses. To address this issue, we monitored by single particle tracking the lateral mobility of individual alpha7-nAChRs labeled with alpha-bungarotoxin linked to quantum dots in live rat cultured hippocampal interneurons. Quantitative analysis revealed different modes of lateral diffusion of alpha7-nAChR dependent on their subcellular localization. Confined receptors were found in the immediate vicinity of glutamatergic and GABAergic postsynaptic densities, as well as in extrasynaptic clusters of alpha-bungarotoxin labeling on dendrites. alpha7-nAChRs avoided entering postsynaptic densities, but exhibited reduced mobility and long dwell times at perisynaptic locations, indicative of regulated confinement. Their diffusion coefficient was lower, on average, at glutamatergic than at GABAergic perisynaptic sites, suggesting differential, synapse-specific tethering mechanisms. Disruption of the cytoskeleton affected alpha7-nAChR mobility and cell surface expression, but not their ability to form clusters. Finally, using tetrodotoxin to silence network activity, as well as exposure to a selective alpha7-nAChR agonist or antagonist, we observed that alpha7-nAChRs cell surface dynamics is modulated by chronic changes in neuronal activity. Altogether, given their high Ca(2+)-permeability, our results suggest a possible role of alpha7-nAChR on interneurons for activating Ca(2+)-dependent signaling in the vicinity of GABAergic and glutamatergic synapses. PMID:20634896

  14. Cross-sections for Balmer-alpha excitation in heavy-particle collisions

    SciTech Connect

    Bae, Y.K.

    1982-08-01

    Doppler shifted and unshifted Balmer-alpha radiation has been observed in the absolute sense for energetic H/sup +/, H/sub 2//sup +/ and H/sub 3//sup +/ ions incident on molecular hydrogen by the method of decay inside the target within the energy range of 20 keV to 150 keV. Most of the measurements were based on single-collision conditions, but a simple thick-target experiment has been tried for the case of dissociative excitation of the target molecules by H atoms.

  15. Scintillation Response of Liquid Xenon to Low Energy Nuclear Recoils

    E-print Network

    E. Aprile; K. L. Giboni; P. Majewski; K. Ni; M. Yamashita; R. Hasty; A. Manzur; D. N. McKinsey

    2005-03-29

    Liquid Xenon (LXe) is expected to be an excellent target and detector medium to search for dark matter in the form of Weakly Interacting Massive Particles (WIMPs). Knowledge of LXe ionization and scintillation response to low energy nuclear recoils expected from the scattering of WIMPs by Xe nuclei is important for determining the sensitivity of LXe direct detection experiments. Here we report on new measurements of the scintillation yield of Xe recoils with kinetic energy as low as 10 keV. The dependence of the scintillation yield on applied electric field was also measured in the range of 0 to 4 kV/cm. Results are in good agreement with recent theoretical predictions that take into account the effect of biexcitonic collisions in addition to the nuclear quenching effect.

  16. Interpreting Recoil Motion for Undergraduate Students

    Microsoft Academic Search

    King Fahd

    The phenomenon of recoil is usually explained to students in the context of Newton's Third Law. When an object is launched from a larger one, the recoil of the large object is interpreted as a reaction to the ejection of the smaller one since \\

  17. Alexander Muck RECOIL-INDUCED RESONANCES FOR

    E-print Network

    Raizen, Mark G.

    the experiment and for the interesting discussions about physics and life in general. Daniel Steck supportedCopyright by Alexander M¨uck 1999 #12;RECOIL-INDUCED RESONANCES FOR VELOCIMETRY OF COLD CESIUM THE UNIVERSITY OF TEXAS AT AUSTIN August 1999 #12;RECOIL-INDUCED RESONANCES FOR VELOCIMETRY OF COLD CESIUM ATOMS

  18. Redefining Relative Biological Effectiveness in the Context of the EQDX Formalism: Implications for Alpha-Particle Emitter Therapy

    PubMed Central

    Hobbs, Robert F.; Howell, Roger W.; Song, Hong; Baechler, Sébastien; Sgouros, George

    2014-01-01

    Alpha-particle radiopharmaceutical therapy (?RPT) is currently enjoying increasing attention as a viable alternative to chemotherapy for targeting of disseminated micrometastatic disease. In theory, ?RPT can be personalized through pre-therapeutic imaging and dosimetry. However, in practice, given the particularities of ?-particle emissions, a dosimetric methodology that accurately predicts the thresholds for organ toxicity has not been reported. This is in part due to the fact that the biological effects caused by ?-particle radiation differ markedly from the effects caused by traditional external beam (photon or electron) radiation or ?-particle emitting radiopharmaceuticals. The concept of relative biological effectiveness (RBE) is used to quantify the ratio of absorbed doses required to achieve a given biological response with alpha particles versus a reference radiation (typically a beta emitter or external beam radiation). However, as conventionally defined, the RBE varies as a function of absorbed dose and therefore a single RBE value is limited in its utility because it cannot be used to predict response over a wide range of absorbed doses. Therefore, efforts are underway to standardize bioeffect modeling for different fractionation schemes and dose rates for both nuclear medicine and external beam radiotherapy. Given the preponderant use of external beams of radiation compared to nuclear medicine in cancer therapy, the more clinically relevant quantity, the 2 Gy equieffective dose, EQD2(?/?), has recently been proposed by the ICRU. In concert with EQD2(?/?), we introduce a new, redefined RBE quantity, named RBE2(?/?), as the ratio of the two linear coefficients that characterize the ? particle absorbed dose-response curve and the low-LET megavoltage photon 2 Gy fraction equieffective dose-response curve. The theoretical framework for the proposed new formalism is presented along with its application to experimental data obtained from irradiation of a breast cancer cell line. Radiobiological parameters are obtained using the linear quadratic model to fit cell survival data for MDA-MB-231 human breast cancer cells that were irradiated with either ? particles or a single fraction of low-LET 137Cs ? rays. From these, the linear coefficient for both the biologically effective dose (BED) and the EQD2(?/?) response lines were derived for fractionated irradiation. The standard RBE calculation, using the traditional single fraction reference radiation, gave RBE values that ranged from 2.4 for a surviving fraction of 0.82–6.0 for a surviving fraction of 0.02, while the dose-independent RBE2(4.6) value was 4.5 for all surviving fraction values. Furthermore, bioeffect modeling with RBE2(?/?) and EQD2(?/?) demonstrated the capacity to predict the surviving fraction of cells irradiated with acute and fractionated low-LET radiation, ? particles and chronic exponentially decreasing dose rates of low-LET radiation. RBE2(?/?) is independent of absorbed dose for ?-particle emitters and it provides a more logical framework for data reporting and conversion to equieffective dose than the conventional dose-dependent definition of RBE. Moreover, it provides a much needed foundation for the ongoing development of an ?-particle dosimetry paradigm and will facilitate the use of tolerance dose data available from external beam radiation therapy, thereby helping to develop ?RPT as a single modality as well as for combination therapies. PMID:24502376

  19. Use of neutralized knock-on ion fluxes for alpha-particle confinement studies

    NASA Astrophysics Data System (ADS)

    Nesenevich, V. G.; Afanasyev, V. I.; Goncharov, P. R.; Mironov, M. I.; Petrov, M. P.; Petrov, S. Ya

    2014-12-01

    One of the objectives of neutral particle diagnostics on large tokamaks exploring DT plasma is to measure the distribution functions of fast deuterium (D) and tritium (T) ions in a suprathermal energy range. High energy tails in D,T-ion energy distributions (so-called knock-on ions) appear as a result of close elastic collisions between thermal fuel ions and fusion ?-particles. The knock-on ion density depends directly on the density and energy distribution of the ?-particles. Therefore measurements of the neutralized knock-on D,T-ion fluxes escaping from the plasma volume can provide information on the ?-particle confinement in DT plasma. This paper presents the results of a numerical simulation for the neutralized fast D,T-ion fluxes in the case of ITER fusion plasma. Feasible experimental measurements of the fluxes are considered with respect to the neutral particle diagnostics. We will show that the diagnostics can provide information on the confinement properties of fast ions in DT fusion plasma.

  20. Coincidence measurements between alpha particles and gamma rays in reactions induced by 85 and 155 MeV ¹²C on ¹??Sm

    E-print Network

    Cala, Steven Edward

    1978-01-01

    COINCIDENCE MEASUREMENTS BETWEEN ALPHA PARTICLES AND GAMMA RAYS 12 154 IN REACTIONS INDUCED BY 85 AND 155 MEV C ON Sm A Thesis by STEVEN EDWARD CALA Submitted to the Graduate College of Texas A&M University in partial fulfillment... of the requirement for the degree of MASTER OF SCIENCE August 1978 Major Subject: Chemistry COINCIDENCE MEASUREMENTS BETWEEN ALPHA PARTICLES AND GAMMA RAYS 12 154 IN REACTIONS INDUCED BY 85 AND 155 MEV C ON Sm A Thesis by STEVEN EDWARD CALA Approved...

  1. Production of the therapeutic radionuclides 193mPt and 195mPt with high specific activity via alpha-particle-induced reactions on 192Os.

    PubMed

    Hilgers, K; Coenen, H H; Qaim, S M

    2008-04-01

    For the production of therapy-relevant radionuclides (193m)Pt (T(1/2)=4.33 d) and (195m)Pt (T(1/2)=4.03 d) with a high specific activity, the (192)Os(alpha,n)(195m)Pt and (192)Os(alpha,3n)(193m)Pt nuclear reactions were investigated for the first time from their respective thresholds up to 28 MeV. Thin samples of enriched (192)Os were prepared by electrodeposition on Ni, and the conventional stacked-foil technique was used for cross-section measurements. The calculated thick target yields were found to be 0.013 MBq/microA h for the (192)Os(alpha,n)(195m)Pt reaction in the energy range of E(alpha)=24-->18 MeV, and 0.25 MBq/microA h for the (192)Os(alpha,3n)(193m)Pt reaction in the energy range of E(alpha)=28-->24 MeV. The two radionuclides could not be detected in the interactions of (3)He particles with (192)Os. A production method involving high-current alpha-particle irradiation of enriched (192)Os and efficient chemical separation of radioplatinum was developed. Batch yields of about 1 MBq (195m)Pt and 8.7 MBq (193m)Pt were achieved. Compared to the reactor production these batch yields are very low, but the (192)Os(alpha,n)(195m)Pt and (192)Os(alpha,3n)(193m)Pt reactions are superior with respect to the specific activity of the products which is higher by two orders of magnitude. PMID:18083038

  2. Sub MeV Particles Detection and Identification in the MUNU detector ((1)ISN, IN2P3/CNRS-UJF, Grenoble, France, (2)Institut de Physique, Neuchâtel, Switzerland, (3) INFN, Padova Italy, (4) Physik-Institut, Zürich, Switzerland)

    E-print Network

    M. Avenier; C. Broggini; J. Busto; C. Cerna; V. Chazal; P. Jeanneret; G. Jonkmans; D. H. Koang; J. Lamblin; D. Lebrun; O. Link; R. Lüescher; F. Ouldsada; G. Puglierin; A. Stutz; A. Tadsen; J. -L. Vuilleumier

    2001-07-17

    We report on the performance of a 1 m$^{3}$ TPC filled with CF$_{4}$ at 3 bar, immersed in liquid scintillator and viewed by photomultipliers. Particle detection, event identification and localization achieved by measuring both the current signal and the scintillation light are presented. Particular features of $\\alpha$ particle detection are also discussed. Finally, the ${54}$Mn photopeak, reconstructed from the Compton scattering and recoil angle is shown.

  3. Complex aberrations in lymphocytes exposed to mixed beams of (241)Am alpha particles and X-rays.

    PubMed

    Staaf, Elina; Deperas-Kaminska, Marta; Brehwens, Karl; Haghdoost, Siamak; Czub, Joanna; Wojcik, Andrzej

    2013-08-30

    Modern radiotherapy treatment modalities are associated with undesired out-of-field exposure to complex mixed beams of high and low energy transfer (LET) radiation that can give rise to secondary cancers. The biological effectiveness of mixed beams is not known. The aim of the investigation was the analysis of chromosomal damage in human peripheral blood lymphocytes (PBL) exposed to a mixed beam of X-rays and alpha particles. Using a dedicated exposure facility PBL were exposed to increasing doses of alpha particles (from (241)Am), X-rays and a mixture of both. Chromosomal aberrations were analysed in chromosomes 2, 8 and 14 using fluorescence in situ hybridisation. The found and expected frequencies of simple and complex aberrations were compared. Simple aberrations showed linear dose-response relationships with doses. A higher than expected frequency of simple aberrations was only observed after the highest mixed beam dose. A linear-quadratic dose response curve for complex aberrations was observed after mixed-beam exposure. Higher than expected frequencies of complex aberrations were observed for the two highest doses. Both the linear-quadratic dose-response relationship and the calculation of expected frequencies show that exposure of PBL to mixed beams of high and low LET radiation leads to a higher than expected frequency of complex-type aberrations. Because chromosomal changes are associated with cancer induction this result may imply that the cancer risk of exposure to mixed beams in radiation oncology may be higher than expected based on the additive action of the individual dose components. PMID:23669292

  4. Studies on the variation of the track etch rate along alpha particle trajectories in CR39

    Microsoft Academic Search

    B Dörschel; H Hartmann; K Kadner; P Rö?ler

    1995-01-01

    At the beginning of the etching process a constant track etch rate can be assumed. In deeper detector layers, however, the etch rate varies drastically along the particle trajectories. Consequently, the indirect determination of the track etch rate by measuring the etch pit diameters on the detector surface does not yield correct results. Therefore, a method for the direct measurement

  5. The S{sub E1} factor of the {sup 12}C({alpha},{gamma}){sup 16}O Reaction and the {sup 16}N {beta}-delayed {alpha} Decay

    SciTech Connect

    Tang Xiaodong [University of Notre Dame, Notre Dame, IN 46530 (United States); Rehm, K. E.; Ahmad, I.; Greene, J. P.; Hecht, A. A.; Henderson, D.; Janssens, R. V. F.; Jiang, C. L.; Kahl, D.; Moore, E. F.; Notani, M.; Pardo, R. C.; Patel, N.; Savard, G.; Schiffer, J. P.; Sinha, S.; Shumard, B. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Brune, C. R. [Ohio University, Athens, Ohio 45701 (United States); Champagne, A. [University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Jisonna, L. [Northwestern University, Evanston, Illinois 60208 (United States)] (and others)

    2008-01-24

    The {sup 12}C({alpha},{gamma}){sup 16}O reaction is of great importance for the understanding the nuclear synthesis and explosion mechanism of the supernova. The cross section at the relevant stellar burning energies, around 300 keV, is dominated by the sub-threshold resonances. The {sup 16}N {beta}-delayed {alpha} decay data provide the most sensitive constrain on this sub-threshold resonance. Using twin-ionization chambers, we have measured the {alpha} particles and {sup 12}C recoil nuclei in coincidence. The spectrum has been fitted together with the published {sup 12}C({alpha},{gamma}){sup 16}O data and the elastic scattering phase shift data using R-matrix. The S{sub E1} factor at 300 keV has been determined as 73{+-}21 keVb.

  6. Indirect recoil implantation following nuclear reactions: Theory and potential applications

    NASA Astrophysics Data System (ADS)

    Conlon, T. W.

    1980-04-01

    A general treatment of indirect recoil implantation following nuclear reactions is given for the first time. This method allows implantation into any substrate of a wide range of species produced by nuclear reactions either in a thin sacrificial target or from a solid target. It is demonstrated that this can be done whilst avoiding primary beam damage to the substrate. Two cases are considered, the general one in which non-elastic nuclear reactions produce the recoil species of interest and secondly the special case of elastic recoils. In both cases a number of novel features of the process not previously described are outlined. For example, by controlling the angular acceptance of the substrate for recoil products the method can be tailored to give well controlled implantation profiles very similar to direct implantation (i.e., approximately Gaussian in range) or more extensive depth distributions whose profiles are simply determined by the centre of mass angular distribution of the reaction product. The flux of particles available for implantation is approximately 10 -4 smaller than from direct implantation facilities, but is comparable to the useful implantation dose achieved by the established technique of direct elastic recoil implantation. The radiation damage is little more than that associated with the indirect implant itself in contrast to direct elastic recoil implantation where the potential damage produced often mediates against the use of that technique. The main advantage of this relatively new method over the conventional methods is the wider range of species which can be implanted with minimum damage to the substrate. These include elements which cannot be conveniently produced from ion sources as well as exotic species which cannot be produced other than by nuclear reactions; radioactive species are good examples of both cases. The method could make an impact in a number of areas, for example, for the injection of radioactive isotopes of the substrate in the study of irradiation damage, diffusion and catalysis; thin film technology, device technology, implantation metallurgy and radiotracers are also possible areas of exploitation. A number of applications in the radiotracer area, viz to radiation sensitive materials, specifically for thin layer activation studies, are discussed.

  7. Evaluation of Melt-Grown, ZnO Single Crystals for Use as Alpha-Particle Detectors

    SciTech Connect

    Neal, John S [ORNL; Giles, N. C. [West Virginia University; Yang, Xiaocheng [West Virginia University; Wall, R. Andrew [Wake Forest University, Winston-Salem, NC; Ucer, Burak [Wake Forest University, Winston-Salem, NC; Williams, Richard T. [Wake Forest University, Winston-Salem, NC; Wisniewski, Dariusz J [ORNL; Boatner, Lynn A [ORNL; Rengarajan, Varatharajan [ORNL; Nause, Jeff E [ORNL; Nemeth, Bell [Cermet, Inc., Atlanta

    2008-01-01

    As part of an ongoing investigation of the scintillation properties of zinc-oxide-based scintillators, several melt-grown, ZnO single crystals have been characterized using -particle excitation, infrared reflectance, and room temperature photoluminescence. The crystals, grown by Cermet, Inc. using a pressurized melt growth process, were doped with Group 1 elements (Li), Group 2 elements (Mg), Group 3 elements (Ga, In) and Lanthanides (Gd, Er, Tm). The goals of these studies are to better understand the scintillation mechanisms associated with various members of the ZnO scintillator family and to then use this knowledge to improve the radiation detection capabilities of ZnO-based scintillators. One application for which ZnO is particularly well suited as a scintillator is as the associated particle detector in a deuterium-tritium (D-T) neutron generator. Application requirements include the exclusion of organic materials, outstanding timing resolution, and high radiation resistance. ZnO(Ga) and ZnO(In) have demonstrated fast (sub-nanosecond) decay times with relatively low light yields, and ZnO(Ga) has been used in a powder form as the associated particle detector for a D-T neutron generator. Four promising candidate materials, ZnO, ZnO:Ga, ZnO:In,Li, and ZnO:Er,Li, were identified in this study. These four samples demonstrated sub-nanosecond decay times and alpha particle excited luminescence comparable to BC-400 fast plastic scintillator. The ZnO:Mg,Ga, ZnO:Gd, and ZnO:Li samples demonstrated appreciable slow (microsecond) decay components that would be incompatible with high-counting-rate applications.

  8. Proton-nucleus optical potential in the alpha-particle model

    NASA Astrophysics Data System (ADS)

    Tan, Zhen-Qiang; Ruan, Wen-Ying

    1990-07-01

    In this paper, by using a phenomenological amplitude fitted with p- 4He elastic scattering data, and on the basis of the ?-particle model of the nucleus, a theoretical proton-nucleus optical potential is constructed. With this potential, the differential cross section, the polarization and the spin-rotation parameter for p- 12C elastic scattering are calculated at Tp = 200 and 398 MeV. The theoretical calculations are in good agreement with the experimental data.

  9. Minimum ionizing and alpha particles detectors based on epitaxial semiconductor silicon carbide

    Microsoft Academic Search

    F. Nava; P. Vanni; M. Bruzzi; S. Lagomarsino; S. Sciortino; G. Wagner; C. Lanzieri

    2004-01-01

    The relatively high value of the energy required to produce an electron-hole pair in silicon carbide, SiC, by a minimum ionizing particle (MIP) against the value for Si, imposes severe constrains in the crystallographic quality, the thickness and the doping concentration of the SiC epitaxial layer used as the detection medium. In this work, a 40 ?m thick 4 H-SiC

  10. Alpha-particle formation and decay rates from Skyrme-HFB wave functions

    NASA Astrophysics Data System (ADS)

    Ward, D. E.; Carlsson, B. G.; Åberg, S.

    2014-05-01

    ? decay is treated microscopically, where the unstable mother nucleus and residual daughter nucleus are described using Hartree-Fock-Bogoliubov (HFB) wave functions, obtained with the Skyrme effective interaction. From these wave functions the amplitude for forming ? particles in the mother nucleus is computed. Two different Skyrme parametrizations with different pairing properties are compared, and we find good agreement with experiment for relative decay rates in both cases. The absolute values of the decay rates are underestimated.

  11. Investigation on polycrystalline CVD diamond-based alpha-particle detectors

    Microsoft Academic Search

    S. G Wang; Q Zhang; S. F Yoon; J Ahn

    2002-01-01

    In this paper, ?-particle detectors have been fabricated using good quality polycrystalline CVD diamond thin films deposited by HFCVD technique. Coplanar electrical contacts with interelectrode spacing of 100?m were prepared on the growth side of the CVD diamond film using lift-off technology. The detector performance has been tested with a 241Am source with a characteristic energy of 5.5MeV at room

  12. Targeting Aberrant DNA double strand break repair in triple negative breast cancer with alpha particle emitter radiolabeled anti-EGFR antibody

    PubMed Central

    Song, Hong; Hedayati, Mohammad; Hobbs, Robert F.; Shao, Chunbo; Bruchertseifer, Frank; Morgenstern, Alfred; DeWeese, Theodore L.; Sgouros, George

    2013-01-01

    The higher potential efficacy of alpha-particle radiopharmaceutical therapy lies in the 3 to 8-fold greater biological effectiveness (RBE) of alpha particles relative to photon or beta-particle radiation. This greater RBE, however, also applies to normal tissue, thereby reducing the potential advantage of high RBE. Since alpha particles typically cause DNA double strand breaks (DSBs), targeting tumors that are defective in DSB repair effectively increases the RBE, yielding a secondary, RBE-based differentiation between tumor and normal tissue that is complementary to conventional, receptor-mediated tumor targeting. In some triple negative breast cancers (TNBC, ER?/PR?/HER-2?), germline mutation in BRCA-1, a key gene in homologous recombination (HR) DSB repair, predisposes patients to early onset of breast cancer. These patients have few treatment options once the cancer has metastasized. In this study, we investigated the efficacy of alpha particle emitter, 213Bi labeled anti-EGFR antibody, Cetuximab, in BRCA-1 defective TNBC. 213Bi-Cetuximab was found to be significantly more effective in the BRCA-1 mutated TNBC cell line HCC1937 than BRCA-1 competent TNBC cell MDA-MB-231. siRNA knockdown of BRCA-1 or DNA-PKcs, a key gene in non-homologous end joining (NHEJ) DSB repair pathway, also sensitized TNBC cells to 213Bi-Cetuximab. Furthermore, the small molecule inhibitor of DNA-PKcs, NU7441, sensitized BRCA-1 competent TNBC cells to alpha particle radiation. Immunofluorescent staining of ?H2AX foci and comet assay confirmed that enhanced RBE is caused by impaired DSB repair. These data offer a novel strategy for enhancing conventional receptor-mediated targeting with an additional, potentially synergistic radiobiological targeting that could be applied to TNBC. PMID:23873849

  13. Targeting aberrant DNA double-strand break repair in triple-negative breast cancer with alpha-particle emitter radiolabeled anti-EGFR antibody.

    PubMed

    Song, Hong; Hedayati, Mohammad; Hobbs, Robert F; Shao, Chunbo; Bruchertseifer, Frank; Morgenstern, Alfred; Deweese, Theodore L; Sgouros, George

    2013-10-01

    The higher potential efficacy of alpha-particle radiopharmaceutical therapy lies in the 3- to 8-fold greater relative biological effectiveness (RBE) of alpha particles relative to photon or beta-particle radiation. This greater RBE, however, also applies to normal tissue, thereby reducing the potential advantage of high RBE. As alpha particles typically cause DNA double-strand breaks (DSB), targeting tumors that are defective in DSB repair effectively increases the RBE, yielding a secondary, RBE-based differentiation between tumor and normal tissue that is complementary to conventional, receptor-mediated tumor targeting. In some triple-negative breast cancers (TNBC; ER(-)/PR(-)/HER-2(-)), germline mutation in BRCA-1, a key gene in homologous recombination DSB repair, predisposes patients to early onset of breast cancer. These patients have few treatment options once the cancer has metastasized. In this study, we investigated the efficacy of alpha-particle emitter, (213)Bi-labeled anti-EGF receptor antibody, cetuximab, in BRCA-1-defective TNBC. (213)Bi-cetuximab was found to be significantly more effective in the BRCA-1-mutated TNBC cell line HCC1937 than BRCA-1-competent TNBC cell MDA-MB-231. siRNA knockdown of BRCA-1 or DNA-dependent protein kinase, catalytic subunit (DNA-PKcs), a key gene in non-homologous end-joining DSB repair pathway, also sensitized TNBC cells to (213)Bi-cetuximab. Furthermore, the small-molecule inhibitor of DNA-PKcs, NU7441, sensitized BRCA-1-competent TNBC cells to alpha-particle radiation. Immunofluorescent staining of ?-H2AX foci and comet assay confirmed that enhanced RBE is caused by impaired DSB repair. These data offer a novel strategy for enhancing conventional receptor-mediated targeting with an additional, potentially synergistic radiobiological targeting that could be applied to TNBC. PMID:23873849

  14. Gas powered fluid gun with recoil mitigation

    DOEpatents

    Grubelich, Mark C; Yonas, Gerold

    2013-11-12

    A gas powered fluid gun for propelling a stream or slug of a fluid at high velocity toward a target. Recoil mitigation is provided that reduces or eliminates the associated recoil forces, with minimal or no backwash. By launching a quantity of water in the opposite direction, net momentum forces are reduced or eliminated. Examples of recoil mitigation devices include a cone for making a conical fluid sheet, a device forming multiple impinging streams of fluid, a cavitating venturi, one or more spinning vanes, or an annular tangential entry/exit.

  15. Further explorations of the alpha-particle optical model potential at low energies for the mass range A=45-209

    E-print Network

    V. Avrigeanu; M. Avrigeanu; C. M?n?ilescu

    2014-10-28

    The recent high-precision measurements of alpha-particle induced reaction data below the Coulomb barrier (B) make possible the understanding of limits and possible improvement of a previous optical model potential (OMP) for alpha-particles on nuclei within the mass number range 45130. Moreover, underestimation of reaction cross sections for well-deformed nuclei is removed by using ~7% larger radius for the surface imaginary part of this spherical OMP. Improved input parameters based on recent independent data, particularly gamma-ray strength functions, but no empirical rescaling factor of the gamma and/or neutron widths have been involved within statistical model calculation of the corresponding (alpha,x) reaction cross sections.

  16. The implications of particle energy and acidic media on gross alpha and gross beta determination using liquid scintillation.

    PubMed

    Zapata-García, D; Llauradó, M; Rauret, G

    2012-04-01

    The interaction of humans with radioactivity present in the environment from natural and artificial sources necessitates an evaluation of its risk on human health. Gross alpha and gross beta activities can provide a rapid evaluation of the radioactive content of a sample and can be simultaneously determined by using liquid scintillation counters. However, calibration of the liquid scintillation counter is required and is affected by many factors, such as particle energy and the acidity of the media. This study investigates what effect the particle energy used for calibration has on misclassification and how to account for this misclassification in routine measurements. The variability in measurement produced by the final pH, as well as any acids used in sample treatment, was also studied. These results showed that the most commonly used acid for these types of analyses, HNO(3), produced a high amount of misclassifications at very low pH. The results improved when HCl was used to adjust the sample to low pH. PMID:22200448

  17. Observation of alpha particle loss from JET plasmas during ion cyclotron resonance frequency heating using a thin foil Faraday cup detector array

    Microsoft Academic Search

    D. S. Darrow; F. E. Cecil; V. Kiptily; K. Fullard; A. Horton; A. Murari; Jet Efda Contributors

    2010-01-01

    The loss of MeV alpha particles from JET plasmas has been measured with a set of thin foil Faraday cup detectors during third harmonic heating of helium neutral beam ions. Tail temperatures of ~2 MeV have been observed, with radial scrape off lengths of a few centimeters. Operational experience from this system indicates that such detectors are potentially feasible for

  18. Radioactive Positron Emitter Production by Energetic Alpha Particles in Solar Flares

    NASA Astrophysics Data System (ADS)

    Murphy, R. J.; Kozlovsky, B.; Share, G. H.

    2014-12-01

    Measurements of the 0.511 MeV positron-annihilation line from solar flares are used to explore the flare process in general and ion acceleration in particular. In flares, positrons are produced primarily by the decay of radioactive positron-emitting isotopes resulting from nuclear interactions of flare-accelerated ions with ambient solar material. Kozlovsky et al. provided ion-energy-dependent production cross sections for 67 positron emitters evaluated from their threshold energies (some <1 MeV nucleon-1) to a GeV nucleon-1, incorporating them into a computer code for calculating positron-emitter production. Adequate cross-section measurements were available for proton reactions, but not for ?-particle reactions where only crude estimates were possible. Here we re-evaluate the ?-particle cross sections using new measurements and nuclear reaction codes. In typical large gamma-ray line flares, proton reactions dominate positron production, but ?-particle reactions will dominate for steeper accelerated-ion spectra because of their relatively low threshold energies. With the accelerated-3He reactions added previously, the code is now reliable for calculating positron production from any distribution of accelerated-ion energies, not just those of typical flares. We have made the code available in the online version of the Journal. We investigate which reactions, projectiles, and ion energies contribute to positron production. We calculate ratios of the annihilation-line fluence to fluences of other gamma-ray lines. Such ratios can be used in interpreting flare data and in determining which nuclear radiation is most sensitive for revealing acceleration of low-energy ions at the Sun.

  19. RADIOACTIVE POSITRON EMITTER PRODUCTION BY ENERGETIC ALPHA PARTICLES IN SOLAR FLARES

    SciTech Connect

    Murphy, R. J. [Code 7650, Naval Research Laboratory, Washington, DC 20375 (United States); Kozlovsky, B. [Tel Aviv University, Tel Aviv (Israel); Share, G. H., E-mail: murphy@ssd5.nrl.navy.mil, E-mail: benz@wise.tau.ac.il, E-mail: share@astro.umd.edu [University of Maryland, College Park, MD 20742 (United States)

    2015-01-01

    Measurements of the 0.511 MeV positron-annihilation line from solar flares are used to explore the flare process in general and ion acceleration in particular. In flares, positrons are produced primarily by the decay of radioactive positron-emitting isotopes resulting from nuclear interactions of flare-accelerated ions with ambient solar material. Kozlovsky et al. provided ion-energy-dependent production cross sections for 67 positron emitters evaluated from their threshold energies (some <1 MeV nucleon{sup –1}) to a GeV nucleon{sup –1}, incorporating them into a computer code for calculating positron-emitter production. Adequate cross-section measurements were available for proton reactions, but not for ?-particle reactions where only crude estimates were possible. Here we re-evaluate the ?-particle cross sections using new measurements and nuclear reaction codes. In typical large gamma-ray line flares, proton reactions dominate positron production, but ?-particle reactions will dominate for steeper accelerated-ion spectra because of their relatively low threshold energies. With the accelerated-{sup 3}He reactions added previously, the code is now reliable for calculating positron production from any distribution of accelerated-ion energies, not just those of typical flares. We have made the code available in the online version of the Journal. We investigate which reactions, projectiles, and ion energies contribute to positron production. We calculate ratios of the annihilation-line fluence to fluences of other gamma-ray lines. Such ratios can be used in interpreting flare data and in determining which nuclear radiation is most sensitive for revealing acceleration of low-energy ions at the Sun.

  20. Optical appearance of alpha particle tracks in CR-39 SSNTD K.N. Yu *, H.H.W. Lee, A.W.T. Wong, Y.L. Law, S.F.L. Cheung, D. Nikezic, F.M.F. Ng

    E-print Network

    Yu, K.N.

    .40; 23.60 Keywords: CR-39 detector; Alpha particles; Tracks; Ray tracing; Gray level 1. Introduction OneOptical appearance of alpha particle tracks in CR-39 SSNTD K.N. Yu *, H.H.W. Lee, A.W.T. Wong, Y of the challenging tasks in the application of solid- state nuclear track detectors (SSNTDs) is the automation

  1. Proton Recoil Energy and Angular Distribution of Neutron Radiative Beta Decay

    E-print Network

    A. N. Ivanov; R. Hollwieser; N. I. Troitskaya; M. Wellenzohn

    2013-09-27

    We analyse the proton recoil energy and angular distribution of the radiative beta-decay of the neutron to leading order in the large baryon mass expansion by taking into account the contributions of the proton-photon correlations. We show that the account for the proton-photon correlations does not contradict the description of the radiative corrections to the lifetime of the neutron and the proton recoil energy spectrum of the neutron beta-decay in terms of the functions (\\alpha/\\pi) g_n(E_e) and (\\alpha/\\pi) f_n(E_e), where E_e is the electron energy. In addition we find that the contributions of the proton-photon correlations in the radiative beta-decay of the neutron to the proton recoil asymmetry C are of order 10^(-4). They make the contributions of the radiative corrections to the proton recoil asymmetry C symmetric with respect to a change A_0 B_0, where A_0 and B_0 are the correlation coefficients of the neutron beta-decay.

  2. Ramsey type Sub-Recoil Cooling

    E-print Network

    Sander, F; Esslinger, T; Hänsch, T W; Sander, Frank; Devolder, Thibaut; Esslinger, Tilman; Hansch, Theodor W.

    1996-01-01

    We experimentally study the motion of atoms interacting with a periodically pulsed near resonant standing wave. For discrete pulse frequencies we observe a comb-like momentum distribution. The peaks have widths of 0.3 recoil momenta and a spacing which is an integer multiple of the recoil momentum. The atomic population is trapped in ground states which periodically evolve to dark states each time the standing wave is switched on.

  3. Applications of 211At and 223Ra in Targeted Alpha-Particle Radiotherapy

    PubMed Central

    Vaidyanathan, Ganesan; Zalutsky, Michael R.

    2012-01-01

    Targeted radiotherapy using agents tagged with ?-emitting radionuclides is gaining traction with several clinical trials already undertaken or ongoing, and others in the advanced planning stage. The most commonly used ?-emitting radionuclides are 213Bi, 211At, 223Ra and 225Ac. While each one of these has pros and cons, it can be argued that 211At probably is the most versatile based on its half life, decay scheme and chemistry. On the other hand, for targeting bone metastases, 223Ra is the ideal radionuclide because simple cationic radium can be used for this purpose. In this review, we will discuss the recent developments taken place in the application of 211At-labeled radiopharmaceuticals and give an overview of the current status of 223Ra for targeted ?-particle radiotherapy. PMID:22202151

  4. Readout cross-talk for alpha-particle measurements in a pixelated sensor system

    NASA Astrophysics Data System (ADS)

    Norlin, B.; Reza, S.; Krapohl, D.; Fröjdh, E.; Thungström, G.

    2015-05-01

    Simulations in Medici are performed to quantify crosstalk and charge sharing in a hybrid pixelated silicon detector. Crosstalk and charge sharing degrades the spatial and spectral resolution of single photon processing X-ray imaging systems. For typical medical X-ray imaging applications, the process is dominated by charge sharing between the pixels in the sensor. For heavier particles each impact generates a large amount of charge and the simulation seems to over predict the charge collection efficiency. This indicates that some type of non modelled degradation of the charge transport efficiency exists, like the plasma effect where the plasma might shield the generated charges from the electric field and hence distorts the charge transport process. Based on the simulations it can be reasoned that saturation of the amplifiers in the Timepix system might generate crosstalk that increases the charge spread measured from ion impact on the sensor.

  5. Applications of 211At and 223Ra in targeted alpha-particle radiotherapy.

    PubMed

    Vaidyanathan, Ganesan; Zalutsky, Michael R

    2011-10-01

    Targeted radiotherapy using agents tagged with ?-emitting radionuclides is gaining traction with several clinical trials already undertaken or ongoing, and others in the advanced planning stage. The most commonly used ?-emitting radionuclides are 213Bi, 211At, 223Ra and 225Ac. While each one of these has pros and cons, it can be argued that 211At probably is the most versatile based on its half life, decay scheme and chemistry. On the other hand, for targeting bone metastases, 223Ra is the ideal radionuclide because simple cationic radium can be used for this purpose. In this review, we will discuss the recent developments taken place in the application of 211At-labeled radiopharmaceuticals and give an overview of the current status of 223Ra for targeted ?-particle radiotherapy. PMID:22202151

  6. Alpha-Particle Emitting 213Bi-Anti-EGFR Immunoconjugates Eradicate Tumor Cells Independent of Oxygenation

    PubMed Central

    Gaertner, Florian C.; Bruchertseifer, Frank; Morgenstern, Alfred; Essler, Markus; Senekowitsch-Schmidtke, Reingard

    2013-01-01

    Hypoxia is a central problem in tumor treatment because hypoxic cells are less sensitive to chemo- and radiotherapy than normoxic cells. Radioresistance of hypoxic tumor cells is due to reduced sensitivity towards low Linear Energy Transfer (LET) radiation. High LET ?-emitters are thought to eradicate tumor cells independent of cellular oxygenation. Therefore, the aim of this study was to demonstrate that cell-bound ?-particle emitting 213Bi immunoconjugates kill hypoxic and normoxic CAL33 tumor cells with identical efficiency. For that purpose CAL33 cells were incubated with 213Bi-anti-EGFR-MAb or irradiated with photons with a nominal energy of 6 MeV both under hypoxic and normoxic conditions. Oxygenation of cells was checked via the hypoxia-associated marker HIF-1?. Survival of cells was analysed using the clonogenic assay. Cell viability was monitored with the WST colorimetric assay. Results were evaluated statistically using a t-test and a Generalized Linear Mixed Model (GLMM). Survival and viability of CAL33 cells decreased both after incubation with increasing 213Bi-anti-EGFR-MAb activity concentrations (9.25 kBq/ml–1.48 MBq/ml) and irradiation with increasing doses of photons (0.5–12 Gy). Following photon irradiation survival and viability of normoxic cells were significantly lower than those of hypoxic cells at all doses analysed. In contrast, cell death induced by 213Bi-anti-EGFR-MAb turned out to be independent of cellular oxygenation. These results demonstrate that ?-particle emitting 213Bi-immunoconjugates eradicate hypoxic tumor cells as effective as normoxic cells. Therefore, 213Bi-radioimmunotherapy seems to be an appropriate strategy for treatment of hypoxic tumors. PMID:23724085

  7. First measurement of the Head-Tail directional nuclear recoil signature at energies relevant to WIMP dark matter searches

    E-print Network

    S. Burgos; E. Daw; J. Forbes; C. Ghag; M. Gold; C. Hagemann; V. A. Kudryavtsev; T. B. Lawson; D. Loomba; P. Majewski; D. Muna; A. StJ. Murphy; G. G. Nicklin; S. M. Paling; A. Petkov; S. J. S. Plank; M. Robinson; N. Sanghi; D. P. Snowden-Ifft; N. J. C. Spooner; J. Turk; E. Tziaferi

    2008-09-10

    We present first evidence for the so-called Head-Tail asymmetry signature of neutron-induced nuclear recoil tracks at energies down to 1.5 keV/amu using the 1m^3 DRIFT-IIc dark matter detector. This regime is appropriate for recoils induced by Weakly Interacting Massive Particle (WIMPs) but one where the differential ionization is poorly understood. We show that the distribution of recoil energies and directions induced here by Cf-252 neutrons matches well that expected from massive WIMPs. The results open a powerful new means of searching for a galactic signature from WIMPs.

  8. Determination of 239Pu and 240Pu isotope ratio for a nuclear bomb particle using X-ray spectrometry in conjunction with gamma-ray spectrometry and non-destructive alpha-particle spectrometry

    Microsoft Academic Search

    R. Pöllänen; K. Ruotsalainen; H. Toivonen

    2009-01-01

    A nuclear bomb particle from Thule containing Pu and U was analyzed using X-ray spectrometry in combination with gamma-ray spectrometry and non-destructive alpha-spectrometry. The main objective was to investigate the possibility to determine the 239Pu and 240Pu isotope ratios. Previously, X-ray spectrometry together with the above-mentioned methods has been successfully applied for radiochemically processed samples, but not for individual particles.

  9. Monte Carlo particle-trajectory models for neutral cometary gases. I. Models and equations. II. The spatial morphology of the Lyman-alpha coma

    SciTech Connect

    Combi, M.R.; Smyth, W.H.

    1988-04-01

    The mathematical derivations of various methods employed in the Monte Carlo particle-trajectory model (MCPTM) are presented, and the application of the MCPTM to the calculation of the photochemical heating of the inner coma through the partial thermalization of cometary hydrogen atoms produced by the photodissociation of water is discussed. This model is then used to explain the observed morphology of the spatially extended Ly-alpha comas of comets. The rocket and Skylab images of the Ly-alpha coma of Comet Kohoutek are examined. 90 references.

  10. Characteristics and mechanisms of the bystander response in monolayer cell cultures exposed to very low fluences of alpha particles

    NASA Astrophysics Data System (ADS)

    Little, John B.; Azzam, Edouard I.; de Toledo, Sonia M.; Nagasawa, Hatsumi

    2005-02-01

    When confluent cultures of mammalian cells are irradiated with very low fluences of alpha particles whereby only occasional cells receive any radiation exposure, genetic changes are observed in the non-irradiated ("bystander") cells. Upregulation of the p53 damage-response pathway as well as activation of proteins in the MAPK family occurred in bystander cells; p53 was phosphorylated on the serine 15 residue suggesting that the upregulation of p53 was a consequence of DNA damage. Damage signals were transmitted to bystander cells through gap junctions, as confirmed by the use of genetically manipulated cells including connexin43 knockouts. Expression of connexin43 was markedly enhanced by irradiation. A moderate bystander effect was observed for specific gene mutations and chromosomal aberrations. This effect was markedly enhanced in cells defective in the non-homologous end joining DNA repair pathway. Finally, an upregulation of oxidative metabolism occurred in bystander cells; the increased levels of reactive oxygen species appeared to be derived from flavine-containing oxidase enzymes. We hypothesize that genetic effects observed in non-irradiated bystander cells are a consequence of oxidative base damage; >90% of mutations in bystander cells were point mutations. When bystander cells cannot repair DNA double strand breaks, they become much more sensitive to the induction of chromosomal aberrations and mutations, the latter consisting primarily of deletion mutants. While we propose that the genetic effects occurring in bystander cells are a consequence of oxidative stress, the nature of the signal that initiates this process remains to be determined.

  11. Cell Cycle Checkpoint Proteins p21 and Hus1 Regulating Intercellular Signaling Induced By Alpha Particle Irradiation

    NASA Astrophysics Data System (ADS)

    Wu, Lijun; Zhao, Ye; Wang, Jun; Hang, Haiying

    In recent years, the attentions for radiation induced bystander effects (RIBE) have been paid on the intercellular signaling events connecting the irradiated and non-irradiated cells. p21 is a member of the Cip/Kip family and plays essential roles in cell cycle progression arrest after cellular irradiation. DNA damage checkpoint protein Hus1 is a member of the Rad9-Rad1-Hus1 complex and functions as scaffold at the damage sites to facilitate the activation of downstream effectors. Using the medium trasfer method and the cells of MEF, MEF (p21-/-), MEF (p21-/-Hus1-/-) as either medium donor or receptor cells, it was found that with 5cGy alpha particle irradiation, the bystander cells showed a significant induction of -H2AX for normal MEFs (p¡0.05). However, the absence of p21 resulted in deficiency in inducing bystander effects. Further results indicated p21 affected the intercellular DNA damage signaling mainly through disrupting the production or release of the damage signals from irradiated cells. When Hus1 and p21 were both knocked out, an obvious induction of -H2AX recurred in bystander cells and the induction of -H2AX was GJIC (gap junction-mediated intercellular communication) dependent, indicating the interrelationship between p21 and Hus1 regulated the production and relay of DNA damage signals from irradiated cells to non-irradiated bystander cells.

  12. Calculation of effective atomic number and electron density of essential biomolecules for electron, proton, alpha particle and multi-energetic photon interactions

    NASA Astrophysics Data System (ADS)

    Kurudirek, Murat; Onaran, Tayfur

    2015-07-01

    Effective atomic numbers (Zeff) and electron densities (Ne) of some essential biomolecules have been calculated for total electron interaction, total proton interaction and total alpha particle interaction using an interpolation method in the energy region 10 keV-1 GeV. Also, the spectrum weighted Zeff for multi-energetic photons has been calculated using Auto-Zeff program. Biomolecules consist of fatty acids, amino acids, carbohydrates and basic nucleotides of DNA and RNA. Variations of Zeff and Ne with kinetic energy of ionizing charged particles and effective photon energies of heterogeneous sources have been studied for the given materials. Significant variations in Zeff and Ne have been observed through the entire energy region for electron, proton and alpha particle interactions. Non-uniform variation has been observed for protons and alpha particles in low and intermediate energy regions, respectively. The maximum values of Zeff have found to be in higher energies for total electron interaction whereas maximum values have found to be in relatively low energies for total proton and total alpha particle interactions. When it comes to the multi-energetic photon sources, it has to be noted that the highest Zeff values were found at low energy region where photoelectric absorption is the pre-dominant interaction process. The lowest values of Zeff have been shown in biomolecules such as stearic acid, leucine, mannitol and thymine, which have highest H content in their groups. Variation in Ne seems to be more or less the same with the variation in Zeff for the given materials as expected.

  13. Neutron scattering facility for the calibration of the response to nuclear recoils

    Microsoft Academic Search

    J. Jochum; B. Chambon; D. Drain; F. von Feilitzsch; J. Gascon; M. Huber; T. Jagemann; M. de Jésus; T. Lachenmaier; J.-C. Lanfranchi; O. Martineau; W. Potzel; A. Rüdig; J. Schnagl; E. Simon; M. Stark; M. Stern; H. Wulandari

    2002-01-01

    A possibility to search for elementary particles as dark matter candidates is to detect elastic scattering with cryogenic detectors. For the interpretation of the data one has to determine the detector response to nuclear recoils, the so-called quenching factors. They can differ for the heat-, for the scintillation- and for the ionization-signal and can be measured by scattering of neutrons.

  14. Low-altitude measurements of precipitating protons, alpha particles, and heavy ions during the geomagnetic storm on March 26-27, 1976

    NASA Technical Reports Server (NTRS)

    Scholer, M.; Hovestadt, D.; Hartmann, G.; Blake, J. B.; Fennell, J. F.; Gloeckler, G.

    1979-01-01

    During the geomagnetic storm of March 16-17, 1976, observations were made of precipitating protons, alpha particles, and heavy ions by two counter telescopes aboard the low-altitude S3-2 satellite. These observations are presented in this paper and their significance discussed. Briefly, a two-zone precipitation region is observed on the nightside, at L equals 2.7 and L equals 4.0 with an alpha/p ratio of about 0.008 in the low-latitude region and about 0.0009 at higher latitude at 0.4 MeV/necleon. The heavier ions, CNO nuclei, are seen in the low-latitude zone with a CNO/alpha ratio of about 0.056 at 0.25 MeV/nucleon.

  15. Reexamination of the {alpha}-{alpha}''fishbone'' potential

    SciTech Connect

    Day, J. P.; McEwen, J. E.; Elhanafy, M.; Smith, E.; Woodhouse, R.; Papp, Z. [Department of Physics and Astronomy, California State University Long Beach, Long Beach, California (United States)

    2011-09-15

    The fishbone potential of composite particles simulates the Pauli effect by nonlocal terms. We determine the {alpha}-{alpha} fishbone potential by simultaneously fitting to two-{alpha} resonance energies, experimental phase shifts, and three-{alpha} binding energies. We found that, essentially, a simple Gaussian can provide a good description of two-{alpha} and three-{alpha} experimental data without invoking three-body potentials.

  16. Non-destructive alpha-particle activation analysis of P, Cl, K and Ca in marine macro-alga samples using synthetic multielement reference material as comparative standard

    Microsoft Academic Search

    Y. Iwata; H. Naitoh; N. Suzuki

    1992-01-01

    A Synthetic Reference Material (SyRM) composed with accurately known amounts of 12 elements has been prepared. The elemental composition of the SyRM is closely similar to that of marine macro-algac sample. The elemental composition of the SyRM was regulated by the starting materials used for the synthesis. The SyRM was used as a comparative standard for non-destructive alpha-particle activation analysis

  17. Observation of alpha particle loss from JET plasmas during ion cyclotron resonance frequency heating using a thin foil Faraday cup detector array.

    PubMed

    Darrow, D S; Cecil, F E; Kiptily, V; Fullard, K; Horton, A; Murari, A

    2010-10-01

    The loss of MeV alpha particles from JET plasmas has been measured with a set of thin foil Faraday cup detectors during third harmonic heating of helium neutral beam ions. Tail temperatures of ? 2?MeV have been observed, with radial scrape off lengths of a few centimeters. Operational experience from this system indicates that such detectors are potentially feasible for future large tokamaks, but careful attention to screening rf and MHD induced noise is essential. PMID:21058457

  18. Observation of alpha particle loss from JET plasmas during ion cyclotron resonance frequency heating using a thin foil Faraday cup detector array

    SciTech Connect

    Darrow, D. S. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Cecil, F. E. [Physics Department, Colorado School of Mines, Golden, Colorado 80401 (United States); Kiptily, V.; Fullard, K.; Horton, A. [Culham Centre for Fusion Energy, Euratom/CCFE Fusion Assoc., Abingdon, Oxon OX14 3DB (United Kingdom); Murari, A. [Consorzio RFX-Associazione EURATOM ENEA per la Fusione, I-35127 Padova (Italy); Collaboration: JET EFDA Contributors

    2010-10-15

    The loss of MeV alpha particles from JET plasmas has been measured with a set of thin foil Faraday cup detectors during third harmonic heating of helium neutral beam ions. Tail temperatures of {approx}2 MeV have been observed, with radial scrape off lengths of a few centimeters. Operational experience from this system indicates that such detectors are potentially feasible for future large tokamaks, but careful attention to screening rf and MHD induced noise is essential.

  19. Design and calibration of a two-channel low-noise heterodyne receiver for use in a CO/sub 2/ laser Thomson scattering alpha particle diagnostic

    SciTech Connect

    Bennett, C.A.; Richards, R.K.; Hutchinson, D.P.

    1988-03-01

    A dual channel low noise heterodyne receiver has been constructed as part of a development effort to build a carbon dioxide laser based Thomson scattering alpha particle diagnostic for a burning plasma experiment. The receiver employs two wide bandwidth (>1 GHz) HgCdTe photovoltaic mixers followed by low noise IF amplifiers. A noise equivalent power of less than 3.0 )times) 10/sup -20/ WHz has been demonstrated. Design details and calibration methods are described. 8 refs

  20. Optical-Model Analysis of Alpha-Particle Scattering by 36Ar from 12.83 to 17.83 MeV

    Microsoft Academic Search

    W. J. Wallace; K. R. Knuth; R. H. Davis

    1970-01-01

    Forty-six-point angular distributions for the elastic scattering of alpha particles by 36Ar have been measured with a gas target from 12.83 to 17.83 MeV in 20-keV intervals throughout the angular range from 29.0 to 167.8° (c.m.). Optical-model fits to the data smoothed in energy with a Lorentzian weighting function have been obtained. The computed cross sections were obtained from an

  1. Ab initio alpha-alpha scattering

    E-print Network

    Serdar Elhatisari; Dean Lee; Gautam Rupak; Evgeny Epelbaum; Hermann Krebs; Timo A. Lähde; Thomas Luu; Ulf-G. Meißner

    2015-06-11

    Processes involving alpha particles and alpha-like nuclei comprise a major part of stellar nucleosynthesis and hypothesized mechanisms for thermonuclear supernovae. In an effort towards understanding alpha processes from first principles, we describe in this letter the first ab initio calculation of alpha-alpha scattering. We use lattice effective field theory to describe the low-energy interactions of nucleons and apply a technique called the adiabatic projection method to reduce the eight-body system to an effective two-cluster system. We find good agreement between lattice results and experimental phase shifts for S-wave and D-wave scattering. The computational scaling with particle number suggests that alpha processes involving heavier nuclei are also within reach in the near future.

  2. Ab initio alpha-alpha scattering

    E-print Network

    Elhatisari, Serdar; Rupak, Gautam; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A; Luu, Thomas; Meißner, Ulf-G

    2015-01-01

    Processes involving alpha particles and alpha-like nuclei comprise a major part of stellar nucleosynthesis and hypothesized mechanisms for thermonuclear supernovae. In an effort towards understanding alpha processes from first principles, we describe in this letter the first ab initio calculation of alpha-alpha scattering. We use lattice effective field theory to describe the low-energy interactions of nucleons and apply a technique called the adiabatic projection method to reduce the eight-body system to an effective two-cluster system. We find good agreement between lattice results and experimental phase shifts for S-wave and D-wave scattering. The computational scaling with particle number suggests that alpha processes involving heavier nuclei are also within reach in the near future.

  3. Stopping of 0.3 1.2 MeV/u protons and alpha particles in Si

    NASA Astrophysics Data System (ADS)

    Abdesselam, M.; Ouichaoui, S.; Azzouz, M.; Chami, A. C.; Siad, M.

    2008-09-01

    The stopping cross sections ?(E) of silicon for protons and alpha particles have been measured over the velocity range 0.3-1.2 MeV/u from a Si//SiO2//Si (SIMOX) target using the Rutherford backscattering spectrometry (RBS) with special emphasis put on experimental aspects. A detection geometry coupling simultaneously two solid-state Si detectors placed at 165° and 150° relative to each side of the incident beam direction was used to measure the energies of the scattered ions and determine their energy losses within the stopping medium. In this way, the basic energy parameter, Ex, at the Si/SiO2 interface for a given incident energy E0 is the same for ions backscattered in the two directions off both the Si and O target elements, and systematic uncertainties in the ?(E) data mainly originating from the target thickness are significantly minimized. A powerful computer code has been elaborated for extracting the relevant ?(E) experimental data and the associated overall uncertainty that amounts to less than 3%. The measured ?(E) data sets were found to be in fair agreement with Paul's compilation and with values calculated by the SRIM 06 computer code. In the case of 4He+ ions, experimental data for the ? effective charge parameter have been deduced by scaling the measured stopping cross sections to those of protons crossing the same target with the same velocity, and compared to the predictions of the SRIM 06 computer code. It is found that the ?-parameter values generated by the latter code slightly deviate from experiment over the velocity region around the stopping cross section maximum where strong charge exchanges usually occur.

  4. Elemental Analysis of the Surface of Comet 67p/Churyumov-Gerasimenko with the Alpha Particle X-Ray Spectrometer APXS on the Rosetta Lander Philae: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Klingelhoefer, G.; Schmanke, D.; Girones-Lopez, J.; Brueckner, J.; d'Uston, C.; Economou, T.; Gellert, R.; Markovski, C.

    2014-12-01

    After a 10 years cruise the Rosetta probe has reached its final target, the comet 67P/Churyumov-Gerasimenko. The main objectives of the mission are to gain more knowledge of the composition, the origin and formation of comets and the solar system. After extensive remote exploration of the comet the lander Philae will be separated to land on the comet surface, starting immediately examining its landing site with its scientific payload. Part of this payload is the APXS (Alpha Particle X-Ray Spectrometer). It will measure in situ the chemical composition of the comet's surface and it's changes during the journey of the comet towards the sun. APXS is a combination of two spectrometers in one single instrument. It will irradiate the comet surface using Curium 244 sources, which are emitting alpha-particle and X-rays. In the alpha-mode the instrument uses alpha backscattering spectroscopy to detect lower Z elements like C, N and O and groups of elements with higher Z. In the X-ray mode alpha particle / X-ray induced X-ray spectroscopy (XRF) will allow the detection of most of the higher Z elements from Na up to Ni and above. Both modes will be always run in parallel allowing to determine lower and higher Z elements simultaneously. For 3 years the solar powered Rosetta probe had to pass a hibernation phase because of a long passage far away to the sun. After wakeup in January 2014 an extensive test phase of all instruments and subsystems has been performed, including the APXS. After landing on the comet an intense initial measurement phase of all instruments is planned, the First Science Sequence (FSS). It will be followed by a long term science phase (LTS). As long as possible APXS and the other instruments will continue to measure and monitor the changes and increasing activity of the comet during its journey towards the inner region of the solar system.The project is funded by the German Space Agency DLR under contracts 50 QP 0404 and 50 QP 0902. References: G. Klingelhöfer et al., The Rosetta Alpha Particle X-ray Spectrometer (APXS), Space Science Reviews, Vol.128 (2007) 383-396;

  5. A gun recoil system employing a magnetorheological fluid damper

    Microsoft Academic Search

    Z C Li; J Wang

    2012-01-01

    This research aims to design and control a full scale gun recoil buffering system which works under real firing impact loading conditions. A conventional gun recoil absorber is replaced with a controllable magnetorheological (MR) fluid damper. Through dynamic analysis of the gun recoil system, a theoretical model for optimal design and control of the MR fluid damper for impact loadings

  6. RecoilUtils A ROOT based Analysis Framework for the

    E-print Network

    RecoilUtils A ROOT based Analysis Framework for the HERMES Recoil Detector Andreas Mussgiller DESY finished in February 2006 ­ Silicon detector finished in September 2006 Understand the detectors: Noise IT Seminar, 26/11/07 II. Physikalisches Institut #12;2 Outline The HERMES Recoil Detector General Idea

  7. A Silicon Recoil Detector for the HERMES Experiment

    E-print Network

    A Silicon Recoil Detector for the HERMES Experiment A. Vandenbroucke University Gent INW inside. Recoil Detector 4. Silicon Recoil Detector ª Sensors, Frame, Hybrid, Foils, Tests 5. Summary INW Inside 0 1 2 3 4 5 6 7 8 9 10 RICH SILICON 270 mrad 270 mrad MUON HODOSCOPE WIDE ANGLE FRONT MUON HODO

  8. Variation in RBE for Survival of V79-4 Cells as a Function of Alpha-Particle (Helium Ion) Energy.

    PubMed

    Tracy, Bliss L; Stevens, David L; Goodhead, Dudley T; Hill, Mark A

    2015-07-01

    High linear energy transfer (LET) ? particles are important with respect to the carcinogenic risk associated with human exposure to ionizing radiation, most notably to radon and its progeny. Additionally, the potential use of alpha-particle-emitting radionuclides in radiotherapy is increasingly being explored. Within the body the emitted alpha particles slow down, traversing a number of cells with a range of energies and therefore with varying efficiencies at inducing biological response. The LET of the particle typically rises from between ~70-90 keV ?m(-1) at the start of the track (depending on initial energy) to a peak of ~237 keV ?m(-1) towards the end of the track, before falling again at the very end of its range. To investigate the variation in biological response with incident energy, a plutonium-238 alpha-particle irradiator was calibrated to enable studies with incident energies ranging from 4.0 MeV down to 1.1 MeV. The variation in clonogenic survival of V79-4 cells was determined as a function of incident energy, along with the relative variation in the initial yields of DNA double-strand breaks (DSB) measured using the FAR assay. The clonogenic survival data also extends previously published data obtained at the Medical Research Council (MRC), Harwell using the same cells irradiated with helium ions, with energies ranging from 34.9 MeV to 5.85 MeV. These studies were performed in conjunction with cell morphology measurements on live cells enabling the determination of absorbed dose and calculation of the average LET in the cell. The results show an increase in relative biological effectiveness (RBE) for cell inactivation with decreasing helium ion energy (increasing LET), reaching a maximum for incident energies of ~3.2 MeV and corresponding average LET of 131 keV ?m(-1), above which the RBE is observed to fall at lower energies (higher LETs). The effectiveness of single alpha-particle traversals (relevant to low-dose exposure) at inducing cell inactivation was observed to increase with decreasing energy to a peak of ~68% survival probability for incident energies of ~1.8 MeV (average LET of 190 keV ?m(-1)) producing ~0.39 lethal lesions per track. However, the efficiency of a single traversal will also vary significantly with cell morphology and angle of incidence, as well as cell type. PMID:26121227

  9. The Benefits of B ---> K* l+ l- Decays at Low Recoil

    E-print Network

    Christoph Bobeth; Gudrun Hiller; Danny van Dyk

    2010-07-08

    Using the heavy quark effective theory framework put forward by Grinstein and Pirjol we work out predictions for B -> K* l+ l-, l = (e, mu), decays for a softly recoiling K*, i.e., for large dilepton masses sqrt{q^2} of the order of the b-quark mass m_b. We work to lowest order in Lambda/Q, where Q = (m_b, sqrt{q^2}) and include the next-to-leading order corrections from the charm quark mass m_c and the strong coupling at O(m_c^2/Q^2, alpha_s). The leading Lambda/m_b corrections are parametrically suppressed. The improved Isgur-Wise form factor relations correlate the B -> K* l+ l- transversity amplitudes, which simplifies the description of the various decay observables and provides opportunities for the extraction of the electroweak short distance couplings. We propose new angular observables which have very small hadronic uncertainties. We exploit existing data on B -> K* l+ l- distributions and show that the low recoil region provides powerful additional information to the large recoil one. We find disjoint best-fit solutions, which include the Standard Model, but also beyond-the-Standard Model ones. This ambiguity can be accessed with future precision measurements.

  10. Radium-223 dichloride bone-targeted alpha particle therapy for hormone-refractory breast cancer metastatic to bone

    PubMed Central

    2014-01-01

    Background Hormone-refractory breast cancer metastatic to bone is a clinically challenging disease associated with high morbidity, poor prognosis, and impaired quality of life owing to pain and skeletal-related events. In a preclinical study using a mouse model of breast cancer and bone metastases, Ra-223 dichloride was incorporated into bone matrix and inhibited proliferation of breast cancer cells and differentiation of osteoblasts and osteoclasts (all P values?alpha-particle therapy for the treatment of symptomatic bone metastases in patients with castration-resistant prostate cancer. On the basis of a strong preclinical rationale, we used Ra-223 dichloride to treat bone metastases in a patient with breast cancer. Results A 44-year-old white woman with metastatic breast cancer who was estrogen receptor–positive, BRCA1-negative, BRCA2-negative, PIK3CA mutation (p.His1047Arg) positive presented with diffuse bony metastases and bone pain. She had hormone refractory and chemotherapy refractory breast cancer. After Ra-223 therapy initiation her bone pain improved, with corresponding decrease in tumor markers and mixed response in 18F-FDG PET/CT and 18F-NaF bone PET/CT. The patient derived clinical benefit from therapy. Conclusion We have shown that Ra-223 dichloride can be safely administered in a patient with hormone-refractory bone metastasis from breast cancer at the US FDA–approved dose for prostate cancer. Furthermore, because the treatment did not cause any drop in hematologic parameters, it has the potential to be combined with other radiosensitizing therapies, which may include chemotherapy or targeted therapies. Given that Ra-223 dichloride is already commercially available, this case report may help future patients and provide a rationale for initiating clinical research in the use of Ra-223 dichloride to treat bone metastasis from breast cancer. A randomized clinical trial is needed to provide evidence of efficacy, safety, and good outcomes. PMID:25243101

  11. Formation of the isomeric pair {sup 194}Ir{sup m,g} in interactions of {alpha} particles with {sup 192}Os

    SciTech Connect

    Uddin, M. S.; Qaim, S. M. [Institut fuer Neurowissenschaften und Medizin, INM-5: Nuklearchemie, Forschungszentrum Juelich, D-52425 Juelich (Germany); Sudar, S. [Institut fuer Neurowissenschaften und Medizin, INM-5: Nuklearchemie, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute of Experimental Physics, Debrecen University, H-4001 Debrecen (Hungary)

    2011-08-15

    Cross sections were measured by the activation technique for the nuclear processes {sup 192}Os({alpha},d+pn+np){sup 194}Ir{sup m,g} up to {alpha}-particle energies of 39 MeV. From the measured data the isomeric cross-section ratio was deduced as a function of projectile energy. The present experimental data as well as those for the {sup 194}Pt(n,p){sup 194}Ir{sup m,g} reaction, given in the literature, were compared with the results of nuclear model calculations using the code talys, which combines the statistical, precompound, and direct interactions. In general, the experimental data were reproduced well by the model calculations, which were done using relatively low values of {eta} (i.e., {Theta}{sub eff}/{Theta}{sub rigid}). The results provide more evidence for the mass dependence of {eta}. The level density parameter for {sup 194}Ir was determined unambiguously.

  12. Mechanism of the sup 6 Li( e , e prime. alpha. ) reaction

    SciTech Connect

    Mitchell, J.H.; Blok, H.P.; Berman, B.L.; Briscoe, W.J.; Daman, M.A.; Ent, R.; Jans, E.; Lapikas, L.; Steijger, J.J.M. (Department of Physics and Astronomy, Vrije Universiteit, de Boelelaan 1081 (1081 HV Amsterdam) The Netherlands National Instituut voor Kernfysica en Hoge-Energiefysica, P. O. Box 41882 (1009 DB Amsterdam) The Netherlands Center for Nuclear Studies, Department of Physics, George Washington University, Washington, D.C. (USA))

    1991-11-01

    The {sup 6}Li({ital e},{ital e}{prime}{alpha}) reaction has been measured in parallel kinematics. The {ital Q}{sup 2} dependence of both the two-body and three-body breakup of {sup 6}Li has been studied at fixed recoil momentum. In addition, the recoil momentum dependence of the two-body {alpha}-{ital d} breakup has been investigated. The data indicate that the reaction mechanism is quasielastic in these kinematics.

  13. {alpha}-particle production: Direct and compound contribution in the reaction {sup 7}Li+{sup 28}Si at near-barrier energies

    SciTech Connect

    Pakou, A.; Nicolis, N.G.; Papachristodoulou, C. [Department of Physics, The University of Ioannina, GR-45110 Ioannina (Greece); Rusek, K. [Department of Nuclear Reactions, The Andrzej Soltan Institute for Nuclear Studies, Hoza 69, PL-00-681 Warsaw (Poland); Alamanos, N.; Gillibert, A.; Pollacco, E.C. [DSM/DAPNIA CEA SACLAY, F-91191 Gif-sur-Yvette (France); Doukelis, G. [Technical Educational Institute of Athens, GR-12210 Athens (Greece); Kalyva, G.; Lagoyannis, A.; Perdikakis, G.; Spyrou, A.; Zarkadas, Ch. [National Research Center, Demokritos (Greece); Kokkoris, M. [National Technical University of Athens, Athens (Greece); Musumarra, A. [Dipartimento di Metodologie Fisiche e Chimiche per l'Ingegneria dell'Universita di Catania, Catania (Italy); Pierroutsakou, D. [INFN Sezione di Napoli, I-80125 Naples (Italy)

    2005-06-01

    The production of {alpha} particles in the {sup 7}Li+{sup 28}Si reaction was studied at near-barrier energies. Angular distributions were measured at four energies, namely 9, 10, 11, and 13 MeV. The data were treated in a statistical model and DWBA framework to disentangle the degree of competition between direct and compound channels in the reaction and its energy evolution near the barrier. It was found that whereas the compound mechanism is substantial, d transfer and possibly t transfer are the dominant mechanism at near-barrier energies. The influence of the reaction channels on the optical potential threshold anomaly is discussed.

  14. A mechanism of variation in the electrical properties of polycrystalline p-PbSe films as a result of irradiation with {alpha} particles

    SciTech Connect

    Salii, Ya. P. [Stefanik Carpathian-region National University (Ukraine)

    2006-02-15

    The effect of irradiation with 5.5-MeV {alpha} particles on the electrical properties of polycrystalline p-PbSe films is studied. It is found that the concentration (p) and mobility ({mu}) of charge carriers decreases as a result of irradiation. The linear dependence of p and {mu}{sup -1} on the square root of the integrated flux {phi}{sup 1/2} is accounted for on the assumption that interstitial atoms in both sublattices are captured by intrinsic extended defects (dislocations and grain boundaries)

  15. Collective relaxation, single particle motion and short range order in. cap alpha. '-NbD/sub x/: A quasielastic neutron scattering study

    SciTech Connect

    Hempelmann, R.; Richter, D.; Faux, D.A.; Ross, D.K.

    1988-01-01

    Applying both incoherent and coherent quasielastic neutron scattering we have studied simultaneously single particle motion, collective relaxation and short range order of deuterium in ..cap alpha..'-NbD/sub x/. A comparison with recent Monte Carlo simulations lead to a consistent description of all results in terms of strongly repulsive deuterium-deuterium interactions. Relating the independently determined tracer and chemical diffusion coefficients with the also measured structure factor we show experimentally that for lattice gases the de Gennes narrowing Ansatz needs to be modified by correlation factors. 18 refs., 3 figs., 1 tab.

  16. The use of alpha particle tagged neutrons for the inspection of objects on the sea floor for the presence of explosives

    NASA Astrophysics Data System (ADS)

    Valkovic, V.; Sudac, D.; Obhodas, J.; Eleon, C.; Perot, B.; Carasco, C.; Sannié, G.; Boudergui, K.; Kondrasovs, V.; Corre, G.; Normand, S.; Woo, R.; Bourbotte, J. M.

    2013-03-01

    A system using a neutron sensor installed within a Remotely Operated Vehicle (ROV) for underwater inspection has been developed. The system can inspect objects for the presence of threat materials, such as explosives and chemical agents, by using alpha particle tagged neutrons from a sealed tube d+t neutron generator to produce characteristic gamma rays within the interrogated object. Here we show that the measured gamma spectra for commonly found ammunition charged with TNT explosives are dominated by C, O and Fe peaks enabling the underwater determination of explosives inside an ammunition shell.

  17. Black hole as a point radiator and recoil effect on the brane world.

    PubMed

    Frolov, Valeri; Stojkovi?, Dejan

    2002-10-01

    A small black hole attached to a brane in a higher-dimensional space emitting quanta into the bulk may leave the brane as a result of a recoil. We construct a field theory model in which such a black hole is described as a massive scalar particle with internal degrees of freedom. In this model, the probability of transition between the different internal levels is identical to the probability of thermal emission calculated for the Schwarzschild black hole. The discussed recoil effect implies that the thermal emission of the black holes, which might be created by interaction of high energy particles in colliders, could be terminated and the energy nonconservation can be observed in the brane experiments. PMID:12365979

  18. Acoustic studies for alpha background rejection in dark matter bubble chamber detectors

    SciTech Connect

    Bou-Cabo, M.; Felis, I.; Ardid, M.; Collaboration: COUPP Collaboration

    2013-08-08

    COUPP (Chicagoland Observatory for Underground Particle Physics) is an experiment with bubble chambers able to detect dark matter directly either with Spin-Dependent or with Spin-Independent interactions. The target material is a superheated liquid (usually CF3I) that can be bubble nucleated due to nuclear recoils produced by elastic collisions of dark matter particles. The bubble growth inside the chamber is accompanied with an acoustic signature. The acoustic technique has been successfully used to have a good alpha discrimination (about 99%). In this paper, we present different studies and results related with the characterization of the acoustic properties of the detector and the different phenomena involved in the acoustic measurements of the bubble growth, such as sound generation, sound transmission and optimization of piezoelectric transducers.

  19. Acoustic studies for alpha background rejection in dark matter bubble chamber detectors

    NASA Astrophysics Data System (ADS)

    Bou-Cabo, M.; Felis, I.; Ardid, M.; Coupp Collaboration

    2013-08-01

    COUPP (Chicagoland Observatory for Underground Particle Physics) is an experiment with bubble chambers able to detect dark matter directly either with Spin-Dependent or with Spin-Independent interactions. The target material is a superheated liquid (usually CF3I) that can be bubble nucleated due to nuclear recoils produced by elastic collisions of dark matter particles. The bubble growth inside the chamber is accompanied with an acoustic signature. The acoustic technique has been successfully used to have a good alpha discrimination (about 99%). In this paper, we present different studies and results related with the characterization of the acoustic properties of the detector and the different phenomena involved in the acoustic measurements of the bubble growth, such as sound generation, sound transmission and optimization of piezoelectric transducers.

  20. Single and multiple cross sections for ionizing processes of biological molecules by protons and alpha-particle impact: a classical Monte Carlo approach.

    PubMed

    Abbas, I; Champion, C; Zarour, B; Lasri, B; Hanssen, J

    2008-02-21

    A classical trajectory model has been used to predict total cross sections of single and double ionizing processes (including capture processes) for several ion-biological molecule collisional systems in the intermediate and high energy range. In this work, the systems studied are water, adenine or cytosine targets ionized by protons and alpha-particles with kinetic energies ranging from 25 keV amu(-1) to 3000 keV amu(-1). In our approach, we have combined several features of two classical methods namely the classical trajectory Monte Carlo (CTMC) and the classical over-barrier (COB) models. For the water target, our results are compared, for high kinetic energies of incident particles, to the available experimental and theoretical results, and reasonable agreement are generally observed especially for the single ionization (liberated electron moves freely after the collision) and the single capture (liberated electron captured by the projectile), both processes representing ionizing processes. Considering the double ionizing processes which have been largely less studied, the unique comparison concerns the double capture process for alpha+H(2)O collision for which we reproduce the experiment reasonably well. Finally, we present total cross sections of single and double ionizing processes for biological targets such as adenine and cytosine where no experimental results exist till now. PMID:18263940

  1. Do the various radiations present in BNCT act synergistically? Cell survival experiments in mixed alpha-particle and gamma-ray fields.

    PubMed

    Phoenix, Ben; Green, Stuart; Hill, Mark A; Jones, Bleddyn; Mill, Andrew; Stevens, David L

    2009-07-01

    In many radiotherapy situations patients are exposed to mixed field radiation. In particular in BNCT, as with all neutron beam exposures, a significant fraction of the dose is contributed by low LET gamma ray photons. The components of such a mixed field may show a synergistic interaction and produce a greater cell kill effect than would be anticipated from the independent action of the different radiation types. Such a synergy would have important implications for treatment planning and in the interpretation of clinical results. An irradiation setup has been created at the Medical Research Council in Harwell to allow simultaneous irradiation of cells by cobalt-60 gamma rays and plutonium-238 alpha-particles. The setup allows for variation of dose and dose rates for both sources along with variation of the alpha particle energy. A series of cell survival assays for this mixed field have been carried out using V79-4 cells and compared to exposures to the individual components of the field under identical conditions. In the experimental setup described no significant synergistic effect was observed. PMID:19376715

  2. Activation cross sections of $\\alpha$-particle induced nuclear reactions on hafnium and deuteron induced nuclear reaction on tantalum: production of $^{178}$W/$^{178m}$Ta generator

    E-print Network

    Tárk'anyi, F; Ditrói, F; Hermanne, A; Ignatyuk, A V; Uddin, M S

    2014-01-01

    In the frame of a systematic study of charged particle production routes of medically relevant radionuclei, the excitation function for indirect production of $^{178m}$Ta through $^{nat}$Hf($\\alpha$,xn)$^{178}$W-$^{178m}$Ta nuclear reaction was measured for the first time up to 40 MeV. In parallel, the side reactions $^{nat}$Hf($\\alpha$,x)$^{179,177,176,175}$W, $^{183,182,178g,177,176,175}$Ta, $^{179m,177m,175}$Hf were also assessed. Stacked foil irradiation technique and $\\gamma$-ray spectrometry were used. New experimental cross section data for the $^{nat}$Ta(d,xn)$^{178}$W reaction are also reported up to 40 MeV. The measured excitation functions are compared with the results of the ALICE-IPPE, and EMPIRE nuclear reaction model codes and with the TALYS 1.4 based data in the TENDL-2013 library. The thick target yields were deduced and compared with yields of other charged particle ((p,4n), (d,5n) and ($^3$He,x)) production routes for $^{178}$W.

  3. Fabrication of high resolution n-type 4H-SiC epitaxial layer alpha particle detectors, defect characterization and electronic noise analysis

    NASA Astrophysics Data System (ADS)

    Zavalla, Kelvin J.; Chaudhuri, Sandeep K.; Mandal, Krishna C.

    2013-09-01

    In the present work high-resolution alpha particle detectors have been fabricated on high quality 20 ?m thick n-type 4H-SiC epitaxial layers. Schottky barrier detectors have been fabricated by depositing 10 nm thick nickel contacts on the Si face of the epilayers. The detectors were characterized using current-voltage (I-V), capacitance-voltage (CV), alpha spectroscopic measurements, and deep level transient spectroscopy (DLTS). I-V measurements revealed a barrier height of ~1.6 eV, diode ideality factor of 1.09, and leakage current of the order of 14 pA at an operating bias of 110 V. C-V measurements revealed low effective doping concentrations of 3.1 × 1014 cm-3 in the epilayers. A micropipe density lower than 1 cm-2 was evaluated in the epilayers. Pulse-height spectroscopy exhibited energy resolution as high as 0.37 % for 5.48 MeV alpha particles with a detector active area of 11 mm2. A diffusion length of ~13.2 ?m for holes has been determined in these detectors following a calculation based on a drift-diffusion model. Detailed electronic noise analysis in terms of equivalent noise charge (ENC) was carried out to study the effect of various noise components that contribute to the total electronic noise in the detection system. The noise analysis revealed that the white series noise due to the detector capacitance has substantial effect on the detector's overall performance. DLTS measurements have revealed the presence of at least four majority (electron) carrier trap levels that can act as recombination/generation or trapping centers.

  4. Test of statistical model predictions for alpha-particle decay of 90,92,94,96Ru compound nuclei

    Microsoft Academic Search

    B. Fornal; F. Gramegna; G. Prete; G. Nebbia; R. Smith; G. D'erasmo; L. Fiore; A. Pantaleo; G. Viesti; P. Blasi; F. Lucarelli; I. Iori; A. Moroni

    1990-01-01

    The alpha decay of Ru compound nuclei populated in 32S on 58,60,62,64Ni reactions at Ebeam=135-185 MeV has been studied. Experimental data have been compared with statistical model calculations performed with two different computer codes. The quality of the agreement between calculations and experimental data was found, in one case, to depend on the compound nucleus populated. Comparing the results from

  5. Measurement of the OXYGEN-17(PROTON, Alpha Particle) Nitrogen -14 Cross Section at Stellar Energies (proton Energies, Resonant Reaction)

    NASA Astrophysics Data System (ADS)

    Blackmon, Jeffery Curtis

    The isotopic abundance ratio 16O/17O has been shown to be a good probe of mass flow and mixing in stars. This ratio is sensitive to the depth of convective mixing which occurs on the giant branch and to the amount of nonconvective mixing occurring on the main sequence. The interpretation of recent observations of this ratio in red giants is limited by a large uncertainty in the value of the 17O(p, alpha)14N reaction rate. This reaction rate is dominated at stellar energies by a resonance at E_{rm x} = 5673 keV in the compound nucleus 18 F, whose strength was previously uncertain. We have carried out a measurement of the ^ {17}O(p,alpha)^{14 }N cross section at proton energies of 75 keV and 65 keV. Thick, high-purity rm Ta_2O _5 targets enriched to 77% ^ {17}O were used in conjunction with beam currents of 0.45 mA and large-solid-angle detectors. The background for the experiment was measured using targets of natural isotopic composition. The resonance peak was observed in the data collected at 75 keV, and we determined the proton width of the 5673 keV state to be 22 +/- 4 neV. This implies a rate for the 17O(p,alpha)^ {14}N reaction that is ten times greater than the typical rates used previously in stellar models.

  6. Synthesis of single phase. alpha. -Fe, Fe sub 3 C and Fe sub 7 C sub 3 nano-particles by CO sub 2 laser pyrolysis technique

    SciTech Connect

    Eklund, P.C.; Bi, X.X.

    1992-01-01

    Iron-containing catalysts have been known to be useful in assisting the Fischer-Tropsch (FT) reaction for synthesizing hydrocarbons. However, it has been well recognized that iron catalyst are not stable during the reaction but converted into iron carbides. It is thus important to understand the role of the iron carbides in the catalytic reaction of the FT-synthesis. It has been found difficult to produce iron carbide nano-particles as a single phase, because iron carbide phases are only metastable under 1 atm pressure. Iron carbide bulk particles prepared so far are often contaminated with metallic iron, iron oxides and free carbon. In this study, we investigate the synthesis of iron carbide nano-particles using CO{sub 2} laser pyrolysis technique. We show that this technique is successful in synthesizing {alpha}-Fe, Fe{sub 3}C and Fe{sub 7}C{sub 3} nano-particles in their single phase with sizes in the range of 5--20nm. In particular, we have produced for the first time the Fe{sub 7}C{sub 3} which has been known to exist but unable to be produced as a single phase. Furthermore, it is interesting that Fe{sub 5}C{sub 2} which has carbon and iron ratio between Fe{sub 3}C and Fe{sub 7}C{sub 3}, is not seen in any run of our synthesis.

  7. Positronium hyperfine splitting: analytical value at m*alpha^6

    Microsoft Academic Search

    Andrzej Czarnecki; Kirill Melnikov; Alexander Yelkhovsky

    1998-01-01

    We present an analytic calculation of the m*alpha^6 recoil corrections to the\\u000ahyperfine splitting (HFS) of the ground state energy levels in positronium. We\\u000afind \\\\Delta E_{\\\\rm rec} = m alpha^6 (-1\\/6 ln(alpha) + 331\\/432 -ln(2)\\/4 - 17\\u000aZeta(3)\\/(8 pi^2) + 5\\/(12 pi^2)) \\\\approx m alpha^6 (- 1\\/6 ln(alpha) + 0.37632),\\u000aconfirming Pachucki's numerical result \\\\cite{Ph}. We present a complete

  8. Recoil order correction of ^8B beta decay for solar neutrino spectrum

    NASA Astrophysics Data System (ADS)

    Sumikama, Toshiyuki

    2009-10-01

    The solar neutrino spectrum of ^8B has been measured precisely at the Super-Kamiokande and the SNO. For the precise neutrino oscillation parameters, the systematic uncertainty about the ^8B neutrino spectrum without neutrino oscillation need to be reduced. Main uncertainty about the neutrino spectrum is the recoil order correction which includes matrix elements. The weak magnetism and the time component of the axial vector current, which is called the axial charge, are the recoil order correction in the ^8B neutrino spectrum. In the present study, the weak magnetism and the axial charge are determined directly from the beta-decay measurements, which are for the beta-alpha angular correlation term [1] and the recently measured spin-alignment correlation term [2]. I will present the extraction of the recoil order correction and compare it with the previous one [3].[4pt] [1] R.D. McKeown et al., Phys. Rev. C 22, 738 (1980).[0pt] [2] T. Sumikama et al., Phys. Lett. B 664, 235 (2008)[0pt] [3] C.E. Ortiz et al., Phys. Rev. Lett. 85, 2909 (2000), W.T. Winter et al., Phys. Rev. C 73, 025503 (2006).

  9. ESCA studies on recoil implanted aluminum substrates 

    E-print Network

    Mallya, Narayani R.

    1980-01-01

    for recoil 1mplantation of gold in A120&/Al substrates was done. Implantation is a technique which can be used for introducing impurit1es 1nto a substrate. Impurity doped surfaces are 1mportant model systems 1n several current areas of act1ve research... Sam le Pre aration Aluminum foil, 99. 999f. pure and 0. 25 mm th1ck (Alfa-Uentron) is cut 1nto rectangular pieces of 1. 2 cms X 1. 0 cms so as to fit the sample probe of the HP5950A ESCA spectrometer. Each piece is sputter etched with a I Kev argon...

  10. Neutron electric form factor via recoil polarimetry

    SciTech Connect

    Richard Madey; Andrei Semenov; Simon Taylor; Aram Aghalaryan; Erick Crouse; Glen MacLachlan; Bradley Plaster; Shigeyuki Tajima; William Tireman; Chenyu Yan; Abdellah Ahmidouch; Brian Anderson; Razmik Asaturyan; O. Baker; Alan Baldwin; Herbert Breuer; Roger Carlini; Michael Christy; Steve Churchwell; Leon Cole; Samuel Danagoulian; Donal Day; Mostafa Elaasar; Rolf Ent; Manouchehr Farkhondeh; Howard Fenker; John Finn; Liping Gan; Kenneth Garrow; Paul Gueye; Calvin Howell; Bitao Hu; Mark Jones; James Kelly; Cynthia Keppel; Mahbubul Khandaker; Wooyoung Kim; Stanley Kowalski; Allison Lung; David Mack; D. Manley; Pete Markowitz; Joseph Mitchell; Hamlet Mkrtchyan; Allena Opper; Charles Perdrisat; Vina Punjabi; Brian Raue; Tilmann Reichelt; Joerg Reinhold; Julie Roche; Yoshinori Sato; Wonick Seo; Neven Simicevic; Gregory Smith; Samuel Stepanyan; Vardan Tadevosyan; Liguang Tang; Paul Ulmer; William Vulcan; John Watson; Steven Wells; Frank Wesselmann; Stephen Wood; Chen Yan; Seunghoon Yang; Lulin Yuan; Wei-Ming Zhang; Hong Guo Zhu; Xiaofeng Zhu

    2003-05-01

    The ratio of the electric to the magnetic form factor of the neutron, G_En/G_Mn, was measured via recoil polarimetry from the quasielastic d({pol-e},e'{pol-n)p reaction at three values of Q^2 [viz., 0.45, 1.15 and 1.47 (GeV/c)^2] in Hall C of the Thomas Jefferson National Accelerator Facility. Preliminary data indicate that G_En follows the Galster parameterization up to Q^2 = 1.15 (GeV/c)^2 and appears to rise above the Galster parameterization at Q^2 = 1.47 (GeV/c)^2.

  11. High speed imaging system in continuum and H-alpha at the Hida observatory for the study of high energy particles in solar flares

    NASA Astrophysics Data System (ADS)

    Ichimoto, K.; Kawate, T.; Yoshikazu, N.; Ishii, T.; Nagata, S.; Asai, A.; Masuda, S.; Kusano, K.; Yamamoto, T. T.; Minoshima, T.; Yokoyama, T.; Watanabe, K.

    2011-12-01

    Non-thermal particles are the fundamental ingredient of solar flares that carry the bulk energy released from the coronal magnetic fields and cause subsequent heating of the solar atmosphere to produce the radiation of wide range of electro-magnetic waves. The observations of hard X-ray and radio emissions suggest a rapid change of population of high energy particles with a time scale of sub-second. Flare kernels observed in visible lights, ex., H-alpha and continuum, show drastic evolutions in space and time during the rising phase of solar flares, and thought to be representing the locations of the precipitation of high energy particles into the chromosphere. Therefore the observations of flare kernels with high spatial and temporal resolutions provide valuable diagnosis of the distribution of high energy particles together with the information of connectivity of coronal magnetic fields. We developed a new high speed imaging system on a 25cm diameter telescope of the Solar Magnetic Activity Research Telescope (SMART) at the Hida observatory of Kyoto University. Images in H-alpha (width~3A) and continuum (6547A, width~10A) are recorded simultaneously with two CCD cameras with a spatial sampling of 0.2 arcsec/pix, field coverage of 344 arcsec x 258 arcsec, and a frame rate of 30fr/sec. Observation is conducted continuously by focusing a targeted active region every day, while only data sets that capture flare events are permanently stored for further analysis. The spatial and temporal evolutions of flare kernels thus obtained are combined with photospheric vector magnetic field taken by the SMART, SOT/Hinode and HMI/SDO, radio data by NoRH, hard X-ray image by RHESSI, and X-ray / UV images by SXT/Hinode and AIA/SDO to identify the instantaneous locations of high energy particles injection in the corona. In this paper we will present an overview of the observing system and its initial results. This work was carried out by the joint research program of the Solar-Terrestorial Environment Laboratory, Nagoya University.

  12. Low energy ion scattering and recoiling

    NASA Astrophysics Data System (ADS)

    Wayne Rabalais, J.

    1994-01-01

    Ion scattering spectrometry was developed as a surface elemental analysis technique in the late 1960's. Further developments during the 1970's and 80's revealed the ability to obtain surface structural information. The recent use of time-of-flight (TOF) methods has led to a surface crystallography that is sensitive to all elements, including hydrogen, and the ability to directly detect hydrogen adsorption sites. TOF detection of both neutrals and ions provides the high sensitivity necessary for non-destructive analysis. Detection of atoms scattered and recoiled from surfaces in simple collision sequences, together with calculations of shadowing and blocking cones, can now be used to make direct measurements of interatomic spacings and adsorption sites within an accuracy of ? 0.1 Å. Structures are determined by monitoring the angular anisotropies in the scattered primary and recoiled target atom flux. Applications of such surface structure and adsorption site determinations are in the fields of catalysis, thin film growth, and interfaces. This article provides a short historical account of these developments along with some examples of the most recent capabilities of the technique.

  13. I. Excluded Volume Effects in Ising Cluster Distributions and Nuclear Multifragmentation II. Multiple-Chance Effects in Alpha-Particle Evaporation

    SciTech Connect

    Breus, Dimitry E.

    2005-05-16

    In Part 1, geometric clusters of the Ising model are studied as possible model clusters for nuclear multifragmentation. These clusters may not be considered as non-interacting (ideal gas) due to excluded volume effect which predominantly is the artifact of the cluster's finite size. Interaction significantly complicates the use of clusters in the analysis of thermodynamic systems. Stillinger's theory is used as a basis for the analysis, which within the RFL (Reiss, Frisch, Lebowitz) fluid-of-spheres approximation produces a prediction for cluster concentrations well obeyed by geometric clusters of the Ising model. If thermodynamic condition of phase coexistence is met, these concentrations can be incorporated into a differential equation procedure of moderate complexity to elucidate the liquid-vapor phase diagram of the system with cluster interaction included. The drawback of increased complexity is outweighted by the reward of greater accuracy of the phase diagram, as it is demonstrated by the Ising model. A novel nuclear-cluster analysis procedure is developed by modifying Fisher's model to contain cluster interaction and employing the differential equation procedure to obtain thermodynamic variables. With this procedure applied to geometric clusters, the guidelines are developed to look for excluded volume effect in nuclear multifragmentation. In part 2, an explanation is offered for the recently observed oscillations in the energy spectra of {alpha}-particles emitted from hot compound nuclei. Contrary to what was previously expected, the oscillations are assumed to be caused by the multiple-chance nature of {alpha}-evaporation. In a semi-empirical fashion this assumption is successfully confirmed by a technique of two-spectra decomposition which treats experimental {alpha}-spectra has having contributions from at least two independent emitters. Building upon the success of the multiple-chance explanation of the oscillations, Moretto's single-chance evaporation theory is augmented to include multiple-chance emission and tested on experimental data to yield positive results.

  14. Suppression of the Critical Temperature of Superconducting NdFeAs(OF) Single Crystals by Kondo-Like Defect Sites Induced by {alpha}-Particle Irradiation

    SciTech Connect

    Tarantini, C.; Gurevich, A.; Larbalestier, D. C. [National High Magnetic Field Laboratory, Florida State University, Tallahassee, 32310 Florida (United States); Putti, M. [CNR-SPIN and Department of Physics, University of Genova, 16146 Genova (Italy); Shen, Y.; Singh, R. K.; Rowell, J. M.; Newman, N. [Department of Materials Science and Engineering, Arizona State University, Tempe, 85287 Arizona (United States); Cheng Peng; Jia Ying; Wen Haihu [Institute of Physics and National Laboratory of Condensed Matter Physics, Chinese Academy of Sciences, 100190 Beijing (China)

    2010-02-26

    We report the effect of {alpha}-particle irradiation on the reduction of the critical temperature T{sub c} of a NdFeAs(OF) single crystal. Our data indicate that irradiation defects cause both nonmagnetic and magnetic scattering, resulting in the Kondo-like excess resistance {Delta}{rho}(T)propor tolnT over 2 decades in temperatures above T{sub c}. The critical density of magnetic irradiation defects which suppresses T{sub c} is found to be much higher than those for cuprates and multiband BCS superconductors. We suggest that such anomalously weak pair breaking by irradiation defects indicates that magnetic scattering in pnictides is coupled with pairing interactions mediated by spin fluctuations.

  15. Scaling of cross sections for K-electron capture by high-energy protons and alpha-particles from the multielectron atoms

    NASA Technical Reports Server (NTRS)

    Omidvar, K.

    1976-01-01

    Electron capture by protons from H, He, and the K-shell of Ar, and alpha particles from He are considered. It is shown that when a certain function of the experimental cross sections is plotted versus the inverse of the collision energy, at high energies the function falls on a straight line. At lower energies the function concaves up or down, depending on the charge of the projectile, the effective charge and the ionization potential of the electron that is being captured. The plot can be used to predict cross sections where experimental data are not available, and as a guide in future experiments. High energy scaling formulas for K-electron capture by low-charge projectiles are given.

  16. Development of a strongly focusing high-intensity He{sup +} ion source for a confined alpha particle measurement at ITER

    SciTech Connect

    Kisaki, M.; Shinto, K.; Kobuchi, T.; Okamoto, A.; Kitajima, S.; Sasao, M.; Tsumori, K.; Nishiura, M.; Kaneko, O.; Matsuda, Y.; Wada, M.; Sakakita, H.; Kiyama, S.; Hirano, Y. [School of Engineering, Tohoku University, Sendai 980-0579 (Japan); National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Department of Electronics, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan); National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8568 (Japan)

    2008-02-15

    A strongly focusing high-intensity He{sup +} ion source has been designed and constructed as a beam source for a high-energy He{sup 0} beam probe system for diagnosis of fusion produced alpha particles in the thermonuclear fusion plasmas. The He{sup +} beam was extracted from the ion source at an acceleration voltage of 18-35 kV. Temperature distributions of the beam target were observed with an IR camera. The 1/e-holding beam profile half-width was about 15 mm at optimum perveance (Perv) of 0.03 (I{sub beam}=2.4 A). A beam current about 3 A was achieved at an acceleration voltage of 26.7 kV with an arc power of 10 kW (Perv=0.023)

  17. Development of a He{sup -} and He{sup 0} beam source for alpha particle measurement in a burning plasma

    SciTech Connect

    Tanaka, N.; Sasao, M.; Terai, K.; Okamoto, A.; Kitajima, S. [Tohoku University, Aoba, Sendai 980-8579 (Japan); Yamaoka, H. [Harima Institute, RIKEN, Sayo, Hyogo 679-5148 (Japan); Wada, M. [Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)

    2012-02-15

    Proof of principle experiments of neutral helium beam production for alpha particle diagnostics was carried out on a test stand. Negative helium ions were produced in the Li charge exchange cell, in which stable and long time operation was possible. He{sup -} beam was accelerated to 157 keV. Finally, He{sup 0} beam was successfully produced after the flight in the drift-tube through the auto-electron-detachment process from He{sup -} to He{sup 0}. A neutral beam detector using a pyroelectric device was also developed to measure He{sup 0} beam intensity. The metastable component in the neutral helium beam was found to be less than 2%.

  18. Predictive theory for elastic scattering and recoil of protons from 4He

    NASA Astrophysics Data System (ADS)

    Hupin, Guillaume; Quaglioni, Sofia; Navrátil, Petr

    2014-12-01

    Low-energy cross sections for elastic scattering and recoil of protons from 4He nuclei (also known as ? particles) are calculated directly by solving the Schrödinger equation for five nucleons interacting through accurate two- and three-nucleon forces derived within the framework of chiral effective field theory. Precise knowledge of these processes at various proton backscattering/recoil angles and energies is needed for the ion-beam analysis of numerous materials, from the surface layers of solids, to thin films, to fusion-reactor materials. Indeed, the same elastic scattering process, in two different kinematic configurations, can be used to probe the concentrations and depth profiles of either hydrogen or helium. We compare our results to available experimental data and show that direct calculations with modern nuclear potentials can help to resolve remaining inconsistencies among data sets and can be used to predict these cross sections when measurements are not available.

  19. THE NEW HRIBF RECOIL MASS SPECTROMETER | PERFORMANCE AND FIRST RESULTS

    E-print Network

    than 15 years recoil mass spectrometers have served as an important tool for nuclear structure for 146Tm new proton transitions were identi ed possibly from the population of excited states in 145Er . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii Chapter I. THE ROLE OF RECOIL MASS SPECTROMETERS IN NUCLEAR SPECTROSCOPY 1 Nuclear Structure

  20. A Silicon Recoil Detector for the HERMES Experiment

    E-print Network

    A Silicon Recoil Detector for the HERMES Experiment A. Vandenbroucke University Gent On behalf Detector 3. Silicon Recoil Detector ª Sensors, Frame, Hybrid, Foils, Tests 4. Summary DPG Mainz, March 2004 0 1 2 3 4 5 6 7 8 9 10 RICH SILICON 270 mrad 270 mrad MUON HODOSCOPE WIDE ANGLE FRONT MUON HODO

  1. Asymmetry of recoil protons in neutron beta-decay

    E-print Network

    V. Gudkov

    2008-01-31

    A complete analysis of proton recoil asymmetry in neutron decay in the first order of radiative and recoil corrections is presented. The possible contributions from new physics are calculated in terms of low energy coupling constants, and the sensitivity of the measured asymmetry to models beyond the Standard model are discussed.

  2. Development of bubble chambers with enhanced stability and sensitivity to low-energy nuclear recoils

    NASA Astrophysics Data System (ADS)

    Bolte, W. J.; Collar, J. I.; Crisler, M.; Hall, J.; Holmgren, D.; Nakazawa, D.; Odom, B.; O'Sullivan, K.; Plunkett, R.; Ramberg, E.; Raskin, A.; Sonnenschein, A.; Vieira, J. D.

    2007-07-01

    The viability of using Bubble Chambers as dark matter particle detectors is considered. Techniques leading to the enhanced chamber stability needed for this new application are described in detail. Prototype trials show that sensitivity to the low-energy nuclear recoils induced by Weakly Interacting Massive Particles (WIMP) is possible in conditions of extreme insensitivity to minimum ionizing backgrounds. An understanding of detector response is demonstrated using existing theoretical models. We briefly comment on the prospects for detection of supersymmetric dark matter with large CF3I chambers.

  3. Evaluation of internal alpha-particle radiation exposure and subsequent fertility among a cohort of women formerly employed in the radium dial industry.

    PubMed

    Schieve, L A; Davis, F; Roeske, J; Handler, A; Freels, S; Stinchcomb, T; Keane, A

    1997-02-01

    This study examined the effect of internal exposure to alpha-particle radiation on subsequent fertility among women employed in the radium dial industry prior to 1930, when appreciable amounts of radium were often ingested through the practice of pointing the paint brush with the lips. The analysis was limited to women for whom a radium body burden measurement had been obtained and who were married prior to age 45 (n = 603). Internal radiation dose to the ovary was calculated based on initial intakes of radium-226 and radium-228, average ovarian mass, number and energy of alpha particles emitted, fraction of energy absorbed within the ovary, effective retention integrals and estimated photon irradiation. Time between marriage and pregnancy, number of pregnancies and number of live births served as surrogates for fertility. Radiation appeared to have no effect on fertility at estimated cumulative ovarian dose equivalents below 5 Sv; above this dose, however, statistically significant declines in both number of pregnancies and live births were observed. These trends persisted after multivariable adjustment for potential confounding variables and after exclusion of subjects contributing a potential classification or selection bias to the study. Additionally, the high-dose group experienced fewer live births than would have been expected based on population rates. There were no differences in time to first pregnancy between high- and low-dose groups. These results are consistent with earlier studies of gamma-ray exposures and suggest that exposure to high doses of radiation from internally deposited radium reduces fertility rather than inducing sterility. PMID:9008216

  4. Evaluation of internal alpha-particle radiation exposure and subsequent fertility among a cohort of women formerly employed in the radium dial industry

    SciTech Connect

    Schieve, L.A.; Davis, F.; Freels, S. [Univ. of Illinois, Chicago, IL (United States)] [and others

    1997-02-01

    This study examined the effect of internal exposure to {alpha}-particle radiation on subsequent fertility among women employed in radium dial industry prior to 1930, when appreciable amounts of radium were often ingested through the practice of pointing the paint brush with the lips. The analysis was limited to women for whom a radium body burden measurement had been obtained and who were married prior to age 45 (n = 603). Internal radiation dose to the ovary was calculated based on initial intakes of radium-226 and radium-228, average ovarian mass, number and energy of {alpha} particles emitted, fraction of energy absorbed within the ovary, effective retention integrals and estimated photon irradiation. Time between marriage and pregnancy, number of pregnancies and number of live births served as surrogates for fertility. Radiation appeared to have no effect on fertility at estimated cumulative ovarian dose equivalents below 5 Sv; above this dose, however, statistically significant declines in both number of pregnancies and live births were observed. These trends persisted after multivariable adjustment for potential confounding variables and after exclusion of subjects contributing a potential classification or selection bias to the study. Additionally, the high-dose group experienced fewer live births than would have been expected based on population rates. There were no differences in time to first pregnancy between high- and low-dose groups. These results are consistent with earlier studies of {gamma}-ray exposures and suggest that exposure to high doses of radiation from internally deposited radium reduces fertility rather than inducing sterility. 42 refs., 5 tabs.

  5. Determination of alpha quartz particle distribution in respirable coal-mine dust samples and reference standards. Rept. of Investigations\\/1985

    Microsoft Academic Search

    C. W. Huggins; S. N. Johnson; J. M. Segreti; J. G. Snyder

    1985-01-01

    The objective of the Bureau of Mines research was to compare the size distribution of respirable quartz collected at coal mines with that of several reference standards used to quantify quartz in coal-mine dust samples. Particle-size measurements were made on 23 samples and 4 reference standards using a scanning electron microscope in the backscatter electron mode of operation, interfaced with

  6. The Alpha Particle X-Ray Spectrometer APXS on the Rosetta lander Philae to explore the surface of comet 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Klingelhoefer, Goestar; Girones Lopez, Jordi; Schmanke, Dirk; Markovski, Cristina; Brückner, Johannes; d'Uston, Claude; Economu, Tom; Gellert, Ralf

    2015-04-01

    The Rosetta Mission was launched in 2004 with the main objectives to gain a better understanding of the origin and formation of comets and the solar system. After 10 years of cruise Rosetta rendevouded with the comet 67P/Churyumov-Gerasimenko in 2014 to study the nucleus of the comet and its environment. Rosetta consists of an orbiter and a lander (Philae) with 11 and 9 scientific experiments respectively. It did what has never been attempted before, orbiting and landing on a comet. After orbit insertion in August 2014, the main spacecraft will follow the comet for several months to investigate its surface. Subsequently, Philae has been deployed for a safe landing. As part of the lander payload the APXS will measure in situ the chemical composition of the comet's surface and it's changes during the journey of the comet around the sun. The data obtained with the APXS will be used to characterize the surface of the comet, to determine the chemical composition of the dust component, and to compare the dust with known meteorite types. APXS combines an alpha mode for alpha backscattering spectroscopy and an x-ray mode for alpha particle/x-ray induced x-ray spectroscopy (XRF) in one single instrument, being low in mass (640g) and power consumption (1.5 W in operating mode) [4]. The comet surface will be irradiated by a Curium 244 source exciting characteristic x-rays of the elements present in the surface material. The alpha mode will allow detection of elements like C and O and groups of elements with a higher Z. The x-ray-SD-detector will allow the detection of most of the elements from Na up to Ni and above. The design of the Rosetta APX spectrometer is based on the experience gained with the APXS built for Russian and American Mars missions: Mars 96 spacecraft and Mars Pathfinder, MPF [1]. Two APXS were also built for the Mars Exploration Rovers mission of the NASA, MER [2-3]. Acknowledgements This project is funded by the German Space Agency DLR under contracts 50 QP 0404 and 50 QP 0902 and the Max Planck Society. References: [1] Brückner, J., Dreibus, G., Rieder, R., and Wänke, H.: 2003, J. Geophys. Res. 108(E12), 8094. [2] Gellert, R., et al.: 2006, J. Geophys. Res. - Planets 111, E02S05. [3] Klingelhöfer, G., Brückner, J., D'uston, C., Gellert, R. und Rieder, R.: 2007, Space Science Reviews 383, 128.

  7. Soluble tumor necrosis factor (TNF) receptors p55 and p75 and interleukin-10 downregulate TNF-alpha activity during the lung response to silica particles in NMRI mice.

    PubMed

    Huaux, F; Arras, M; Vink, A; Renauld, J C; Lison, D

    1999-07-01

    We have found reduced activity of tumor necrosis factor (TNF)-alpha accompanying resolving and fibrosing alveolitis induced in NMRI mice by mineral particles (MnO2 and SiO2, respectively), which is in apparent contradiction to the well-recognized proinflammatory and profibrotic activities of this cytokine. The objective of this study was to examine the mechanisms involved in this paradoxical response in NMRI mice. Although lung tissue messenger RNA (mRNA) levels for TNF-alpha were transiently (up to 15 d) and persistently (up to 120 d) upregulated in the resolving and fibrosing models, respectively, these changes were not accompanied by a parallel release of TNF-alpha protein, which was respectively transiently and persistently downregulated in bronchoalveolar lavage fluid and bronchoalveolar lavage cell cultures. The downregulation of the TNF-alpha protein was concurrent with the accumulation of recruited polymorphonuclear neutrophils (PMNs) in alveoli, and coculture experiments showed that PMN explanted from the lungs of mice treated with silica particles were able to downregulate the expression of TNF-alpha protein by naive alveolar macrophages. In addition, PMN depletion prevented the downregulation of TNF-alpha induced by silica, further establishing the role of PMNs in the downregulation of TNF-alpha. The possible degradation of TNF-alpha by proteolytic enzymes could be excluded. Marked increases in soluble p55 and p75 TNF receptors (sTNF-R), as well as in interleukin (IL)-10, paralleled the downregulation of TNF-alpha protein. The role of these mediators in the observed reduction of TNF-alpha activity was confirmed by immunoneutralizing the activity of p55 and p75 sTNF-R and by using IL-10-deficient animals. Because IL-10 also exerts profibrotic activity in addition to its antiinflammatory activity, the protracted overproduction of IL-10 observed in fibrosing alveolitis may help the understanding of why, in NMRI mice treated with silica particles, lung fibrosis develops in association with a downregulation of TNF-alpha. PMID:10385602

  8. First In Vivo Evaluation of Liposome-encapsulated 223Ra as a Potential Alpha-particle-emitting Cancer Therapeutic Agent

    SciTech Connect

    Jonasdottir, Thora J.; Fisher, Darrell R.; Borrebaek, Jorgen; Bruland, Oyvind S.; Larsen, Roy H.

    2006-09-13

    Liposomes carrying chemotherapeutics have had some success in cancer treatment and may be suitable carriers for therapeutic radionuclides. This study was designed to evaluate the biodistribution of and to estimate the radiation doses from the alpha emitter 223Ra loaded into pegylated liposomes in selected tissues. 223Ra was encapsulated in pegylated liposomal doxorubicin by ionophore-mediated loading. The biodistribution of liposomal 223Ra was compared to free cationic 223Ra in Balb/C mice. We showed that liposomal 223 Ra circulated in the blood with an initial half-time in excess of 24 hours, which agreed well with that reported for liposomal doxorubicin in rodents, while the blood half-time of cationic 223Ra was considerably less than one hour. When liposomal 223 Ra was catabolized, the released 223Ra was either excreted or taken up in the skeleton. This skeletal uptake increased up to 14 days after treatment, but did not reach the level seen with free 223Ra. Pre-treatment with non-radioactive liposomal doxorubicin 4 days in advance lessened the liver uptake of liposomal 223 Ra. Dose estimates showed that the spleen, followed by bone surfaces, received the highest absorbed doses. Liposomal 223 Ra was relatively stable in vivo and may have potential for radionuclide therapy and combination therapy with chemotherapeutic agents.

  9. DNA Double Strand Breaks as Predictor of Efficacy of the Alpha-Particle Emitter Ac-225 and the Electron Emitter Lu-177 for Somatostatin Receptor Targeted Radiotherapy

    PubMed Central

    Graf, Franziska; Fahrer, Jörg; Maus, Stephan; Morgenstern, Alfred; Bruchertseifer, Frank; Venkatachalam, Senthil; Fottner, Christian; Weber, Matthias M.; Huelsenbeck, Johannes; Schreckenberger, Mathias; Kaina, Bernd; Miederer, Matthias

    2014-01-01

    Rationale Key biologic effects of the alpha-particle emitter Actinium-225 in comparison to the beta-particle emitter Lutetium-177 labeled somatostatin-analogue DOTATOC in vitro and in vivo were studied to evaluate the significance of ?H2AX-foci formation. Methods To determine the relative biological effectiveness (RBE) between the two isotopes (as - biological consequence of different ionisation-densities along a particle-track), somatostatin expressing AR42J cells were incubated with Ac-225-DOTATOC and Lu-177-DOTATOC up to 48 h and viability was analyzed using the MTT assay. DNA double strand breaks (DSB) were quantified by immunofluorescence staining of ?H2AX-foci. Cell cycle was analyzed by flow cytometry. In vivo uptake of both radiolabeled somatostatin-analogues into subcutaneously growing AR42J tumors and the number of cells displaying ?H2AX-foci were measured. Therapeutic efficacy was assayed by monitoring tumor growth after treatment with activities estimated from in vitro cytotoxicity. Results Ac-225-DOTATOC resulted in ED50 values of 14 kBq/ml after 48 h, whereas Lu-177-DOTATOC displayed ED50 values of 10 MBq/ml. The number of DSB grew with increasing concentration of Ac-225-DOTATOC and similarly with Lu-177-DOTATOC when applying a factor of 700-fold higher activity compared to Ac-225. Already 24 h after incubation with 2.5–10 kBq/ml, Ac-225-DOTATOC cell-cycle studies showed up to a 60% increase in the percentage of tumor cells in G2/M phase. After 72 h an apoptotic subG1 peak was also detectable. Tumor uptake for both radio peptides at 48 h was identical (7.5%ID/g), though the overall number of cells with ?H2AX-foci was higher in tumors treated with 48 kBq Ac-225-DOTATOC compared to tumors treated with 30 MBq Lu-177-DOTATOC (35% vs. 21%). Tumors with a volume of 0.34 ml reached delayed exponential tumor growth after 25 days (44 kBq Ac-225-DOTATOC) and after 21 days (34 MBq Lu-177-DOTATOC). Conclusion ?H2AX-foci formation, triggered by beta- and alpha-irradiation, is an early key parameter in predicting response to internal radiotherapy. PMID:24516620

  10. A gun recoil system employing a magnetorheological fluid damper

    NASA Astrophysics Data System (ADS)

    Li, Z. C.; Wang, J.

    2012-10-01

    This research aims to design and control a full scale gun recoil buffering system which works under real firing impact loading conditions. A conventional gun recoil absorber is replaced with a controllable magnetorheological (MR) fluid damper. Through dynamic analysis of the gun recoil system, a theoretical model for optimal design and control of the MR fluid damper for impact loadings is derived. The optimal displacement, velocity and optimal design rules are obtained. By applying the optimal design theory to protect against impact loadings, an MR fluid damper for a full scale gun recoil system is designed and manufactured. An experimental study is carried out on a firing test rig which consists of a 30 mm caliber, multi-action automatic gun with an MR damper mounted to the fixed base through a sliding guide. Experimental buffering results under passive control and optimal control are obtained. By comparison, optimal control is better than passive control, because it produces smaller variation in the recoil force while achieving less displacement of the recoil body. The optimal control strategy presented in this paper is open-loop with no feedback system needed. This means that the control process is sensor-free. This is a great benefit for a buffering system under impact loading, especially for a gun recoil system which usually works in a harsh environment.

  11. Event counting alpha detector

    DOEpatents

    Bolton, Richard D. (Los Alamos, NM); MacArthur, Duncan W. (Los Alamos, NM)

    1996-01-01

    An electrostatic detector for atmospheric radon or other weak sources of alpha radiation. In one embodiment, nested enclosures are insulated from one another, open at the top, and have a high voltage pin inside and insulated from the inside enclosure. An electric field is produced between the pin and the inside enclosure. Air ions produced by collision with alpha particles inside the decay volume defined by the inside enclosure are attracted to the pin and the inner enclosure. With low alpha concentrations, individual alpha events can be measured to indicate the presence of radon or other alpha radiation. In another embodiment, an electrical field is produced between parallel plates which are insulated from a single decay cavity enclosure.

  12. Alpha-Lipoic Acid Reduces LDL-Particle Number and PCSK9 Concentrations in High-Fat Fed Obese Zucker Rats

    PubMed Central

    Carrier, Bradley; Wen, Shin; Zigouras, Sophia; Browne, Richard W.; Li, Zhuyun; Patel, Mulchand S.; Williamson, David L.; Rideout, Todd C.

    2014-01-01

    We characterized the hypolipidemic effects of alpha-lipoic acid (LA, R-form) and examined the associated molecular mechanisms in a high fat fed Zucker rat model. Rats (n?=?8) were assigned to a high fat (HF) diet or the HF diet with 0.25% LA (HF-LA) for 30 days and pair fed to remove confounding effects associated with the anorectic properties of LA. Compared with the HF controls, the HF-LA group was protected against diet-induced obesity (102.5±3.1 vs. 121.5±3.6,% change BW) and hypercholesterolemia with a reduction in total-C (?21%), non-HDL-C (?25%), LDL-C (?16%), and total LDL particle number (?46%) and an increase in total HDL particles (?22%). This cholesterol-lowering response was associated with a reduction in plasma PCSK9 concentration (?70%) and an increase in hepatic LDLr receptor protein abundance (2 fold of HF). Compared with the HF-fed animals, livers of LA-supplemented animals were protected against TG accumulation (?46%), likely through multiple mechanisms including: a suppressed lipogenic response (down-regulation of hepatic acetyl-CoA carboxylase and fatty acid synthase expression); enhanced hepatic fat oxidation (increased carnitine palmitoyltransferase I? expression); and enhanced VLDL export (increased hepatic diacylglycerol acyltransferase and microsomal triglyceride transfer protein expression and elevated plasma VLDL particle number). Study results also support an enhanced fatty acid uptake (2.8 fold increase in total lipase activity) and oxidation (increased CPT1? protein abundance) in muscle tissue in LA-supplemented animals compared with the HF group. In summary, in the absence of a change in caloric intake, LA was effective in protecting against hypercholesterolemia and hepatic fat accumulation under conditions of strong genetic and dietary predisposition toward obesity and dyslipidemia. PMID:24595397

  13. Absolute ionization yield of 6.7 keV argon nuclear recoils in liquid argon

    NASA Astrophysics Data System (ADS)

    Sorensen, Peter

    2014-09-01

    We have made a first measurement of the total electronic energy loss of low-energy argon atoms stopping in liquid argon. The importance of the measurement is underscored by the fact that state of the art theoretical treatment of this problem is only approximate. While these results are of modest interest to condensed matter theory, they are of keen interest to experiments seeking to directly detect signals due to nuclear recoils. Two particular interactions which would result in nuclear recoil signals are the scattering of hypothetical dark matter particles, or coherent elastic neutrino nucleus scattering. Using quasi mono-energetic neutrons from a collimated and filtered 7Li(p,n) source, we measured the absolute ionization yield of nuclear recoils in liquid argon at 6.7 keV at applied electric fields ranging from 200--2130 V/cm. We will discuss the experimental setup used for these measurements, our findings and their implications, and finally our recent efforts to apply this technique to liquid xenon.

  14. Difference between a Photon's Momentum and an Atom's Recoil

    SciTech Connect

    Gibble, Kurt [Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2006-08-18

    When an atom absorbs a photon from a laser beam that is not an infinite plane wave, the atom's recoil is less than ({Dirac_h}/2{pi})k in the propagation direction. We show that the recoils in the transverse directions produce a lensing of the atomic wave functions, which leads to a frequency shift that is not discrete but varies linearly with the field amplitude and strongly depends on the atomic state detection. The same lensing effect is also important for microwave atomic clocks. The frequency shifts are of the order of the naive recoil shift for the transverse wave vector of the photons.

  15. Stellar and Primordial Nucleosynthesis of Be7: Measurement of He3(alpha,gamma)Be7

    Microsoft Academic Search

    A. di Leva; L. Gialanella; R. Kunz; D. Rogalla; D. Schürmann; F. Strieder; M. de Cesare; N. de Cesare; A. D'Onofrio; Z. Fülöp; G. Gyürky; G. Imbriani; G. Mangano; A. Ordine; V. Roca; C. Rolfs; M. Romano; E. Somorjai; F. Terrasi

    2009-01-01

    The He3(alpha,gamma)Be7 reaction presently represents the largest nuclear uncertainty in the predicted solar neutrino flux and has important implications on the big bang nucleosynthesis, i.e., the production of primordial Li7. We present here the results of an experiment using the recoil separator ERNA (European Recoil separator for Nuclear Astrophysics) to detect directly the Be7 ejectiles. In addition, off-beam activation and

  16. Analysis of accelerator based neutron spectra for BNCT using proton recoil spectroscopy

    SciTech Connect

    Wielopolski, L.; Ludewig, H.; Powell, J.R.; Raparia, D.; Alessi, J.G.; Lowenstein, D.I.

    1999-03-01

    Boron Neutron Capture Therapy (BNCT) is a promising binary treatment modality for high-grade primary brain tumors (glioblastoma multiforme, GM) and other cancers. BNCT employs a boron-10 containing compound that preferentially accumulates in the cancer cells in the brain. Upon neutron capture by {sup 10}B energetic alpha particles and triton released at the absorption site kill the cancer cell. In order to gain penetration depth in the brain Fairchild proposed, for this purpose, the use of energetic epithermal neutrons at about 10 keV. Phase 1/2 clinical trials of BNCT for GM are underway at the Brookhaven Medical Research Reactor (BMRR) and at the MIT Reactor, using these nuclear reactors as the source for epithermal neutrons. In light of the limitations of new reactor installations, e.g. cost, safety and licensing, and limited capability for modulating the reactor based neutron beam energy spectra, alternative neutron sources are being contemplated for wider implementation of this modality in a hospital environment. For example, accelerator based neutron sources offer the possibility of tailoring the neutron beams, in terms of improved depth-dose distributions, to the individual and offer, with relative ease, the capability of modifying the neutron beam energy and port size. In previous work new concepts for compact accelerator/target configuration were published. In this work, using the Van de Graaff accelerator the authors have explored different materials for filtering and reflecting neutron beams produced by irradiating a thick Li target with 1.8 to 2.5 MeV proton beams. However, since the yield and the maximum neutron energy emerging from the Li-7(p,n)Be-7 reaction increase with increase in the proton beam energy, there is a need for optimization of the proton energy versus filter and shielding requirements to obtain the desired epithermal neutron beam. The MCNP-4A computer code was used for the initial design studies that were verified with benchmark experiments using a proton recoil spectroscopy detection system. Comparison was also made between in phantom {sup 10}BF{sub 3} readings made at the BMRR and those made at the RARAF accelerator facility.

  17. ANALYSIS OF ACCELERATOR BASED NEUTRON SPECTRA FOR BNCT USING PROTON RECOIL SPECTROSCOPY

    SciTech Connect

    WIELOPOLSKI,L.; LUDEWIG,H.; POWELL,J.R.; RAPARIA,D.; ALESSI,J.G.; LOWENSTEIN,D.I.

    1998-11-06

    Boron Neutron Capture Therapy (BNCT) is a promising binary treatment modality for high-grade primary brain tumors (glioblastoma multiforme, GM) and other cancers. BNCT employs a boron-10 containing compound that preferentially accumulates in the cancer cells in the brain. Upon neutron capture by {sup 10}B energetic alpha particles and triton released at the absorption site kill the cancer cell. In order to gain penetration depth in the brain Fairchild proposed, for this purpose, the use of energetic epithermal neutrons at about 10 keV. Phase I/II clinical trials of BNCT for GM are underway at the Brookhaven Medical Research Reactor (BMRR) and at the MIT Reactor, using these nuclear reactors as the source for epithermal neutrons. In light of the limitations of new reactor installations, e.g. cost, safety and licensing, and limited capability for modulating the reactor based neutron beam energy spectra alternative neutron sources are being contemplated for wider implementation of this modality in a hospital environment. For example, accelerator based neutron sources offer the possibility of tailoring the neutron beams, in terms of improved depth-dose distributions, to the individual and offer, with relative ease, the capability of modifying the neutron beam energy and port size. In previous work new concepts for compact accelerator/target configuration were published. In this work, using the Van de Graaff accelerator the authors have explored different materials for filtering and reflecting neutron beams produced by irradiating a thick Li target with 1.8 to 2.5 MeV proton beams. However, since the yield and the maximum neutron energy emerging from the Li-7(p,n)Be-7 reaction increase with increase in the proton beam energy, there is a need for optimization of the proton energy versus filter and shielding requirements to obtain the desired epithermal neutron beam. The MCNP-4A computer code was used for the initial design studies that were verified with benchmark experiments using a proton recoil spectroscopy detection system. Comparison was also made between in phantom {sup 10}BF{sub 3} readings made at the BMRR and those made at the RARAF accelerator facility.

  18. Condition detection and fault diagnosis system for recoil system based on simulation

    Microsoft Academic Search

    Lijun Cao; Huibin Hu; Junqi Qin

    2009-01-01

    Dynamic analysis is carried out for recoil parts in recoil and counter-recoil process to find out the fault effects of liquid and gas leakage of recoil brake and recuperator. In order to detect and simulate the fault occurrence and development process, virtual prototyping is firstly adopted into fault simulation and detection fields in this paper. The basic steps of virtual

  19. The Apollo Alpha Spectrometer.

    NASA Technical Reports Server (NTRS)

    Jagoda, N.; Kubierschky, K.; Frank, R.; Carroll, J.

    1973-01-01

    Located in the Science Instrument Module of Apollo 15 and 16, the Alpha Particle Spectrometer was designed to detect and measure the energy of alpha particles emitted by the radon isotopes and their daughter products. The spectrometer sensor consisted of an array of totally depleted silicon surface barrier detectors. Biased amplifier and linear gate techniques were utilized to reduce resolution degradation, thereby permitting the use of a single 512 channel PHA. Sensor identification and in-flight radioactive calibration were incorporated to enhance data reduction.

  20. Heavy-to-light meson form factors at large recoil

    Microsoft Academic Search

    Richard J. Hill

    2006-01-01

    Heavy-to-light meson form factors at large recoil can be described using the same techniques as for hard exclusive processes involving only light hadrons. Two competing mechanisms appear in the large recoil regime, describing so-called ``soft-overlap'' and ``hard-scattering'' components of the form factors. It is shown how existing experimental data from B and D decays constrain the relative size of these

  1. Heavy-to-light Meson Form Factors at Large Recoil

    Microsoft Academic Search

    Richard J. Hill

    2005-01-01

    Heavy-to-light meson form factors at large recoil can be described using the same techniques as for hard exclusive processes involving only light hadrons. Two competing mechanisms appear in the large-recoil regime, describing so-called ''soft-overlap'' and ''hard-scattering'' components of the form factors. It is shown how existing experimental data from B and D decays constrain the relative size of these components,

  2. Heavy-to-light meson form factors at large recoil

    Microsoft Academic Search

    Richard J. Hill; Richard J

    2006-01-01

    Heavy-to-light meson form factors at large recoil can be described using the same techniques as for hard exclusive processes involving only light hadrons. Two competing mechanisms appear in the large recoil regime, describing so-called 'soft-overlap' and 'hard-scattering' components of the form factors. It is shown how existing experimental data from B and D decays constrain the relative size of these

  3. Alpha Thalassemia

    MedlinePLUS

    ... the anemia. Normal alpha globin genes found on chromosome 16 People who do not produce enough alpha ... by four genes, two on each strand of chromosome 16. Individuals who have one or two abnormal ...

  4. Sequential Cytarabine and Alpha-Particle Immunotherapy with Bismuth-213-Lintuzumab (HuM195) for Acute Myeloid Leukemia

    PubMed Central

    Rosenblat, Todd L.; McDevitt, Michael R.; Mulford, Deborah A.; Pandit-Taskar, Neeta; Divgi, Chaitanya R.; Panageas, Katherine S.; Heaney, Mark L.; Chanel, Suzanne; Morgenstern, Alfred; Sgouros, George; Larson, Steven M.; Scheinberg, David A.; Jurcic, Joseph G.

    2010-01-01

    Purpose Lintuzumab (HuM195), a humanized anti-CD33 antibody, targets myeloid leukemia cells and has modest single-agent activity against acute myeloid leukemia (AML). To increase the antibody’s potency without the nonspecific cytotoxicity associated with ?-emitters, the ? particle-emitting radionuclide bismuth-213 (213Bi) was conjugated to lintuzumab. This phase I/II trial was conducted to determine the maximum tolerated dose (MTD) and antileukemic effects of 213Bi-lintuzumab, the first targeted ?-emitter, after partially cytoreductive chemotherapy. Experimental Design Thirty-one patients with newly diagnosed (n = 13) or relapsed/refractory (n = 18) AML (median age, 67 years; range, 37–80) were treated with cytarabine 200 mg/m2/day for 5 days followed by 213Bi-lintuzumab 18.5–46.25 MBq/kg. Results The MTD of 213Bi-lintuzumab was 37 MB/kg; myelosuppression lasting > 35 days was dose-limiting. Extramedullary toxicities were primarily limited to ? grade 2 events, including infusion-related reactions. Transient grade 3/4 liver function abnormalities were seen in 5 patients (16%). Treatment-related deaths occurred in 2 of 21 patients (10%) who received the MTD. Significant reductions in marrow blasts were seen at all dose levels. The median response duration was 6 months (range, 2–12). Biodistribution and pharmacokinetic studies suggested that saturation of available CD33 sites by 213Bi-lintuzumab was achieved after partial cytoreduction with cytarabine. Conclusions Sequential administration of cytarabine and 213Bi-lintuzumab is tolerable and can produce remissions in patients with AML. PMID:20858843

  5. Alpha particle and proton relative thermoluminescence efficiencies in LiF:Mg,Cu,P:is track structure theory up to the task?

    PubMed

    Horowitz, Y S; Siboni, D; Oster, L; Livingstone, J; Guatelli, S; Rosenfeld, A; Emfietzoglou, D; Bilski, P; Obryk, B

    2012-07-01

    Low-energy alpha particle and proton heavy charged particle (HCP) relative thermoluminescence (TL) efficiencies are calculated for the major dosimetric glow peak in LiF:Mg,Cu,P (MCP-N) in the framework of track structure theory (TST). The calculations employ previously published TRIPOS-E Monte Carlo track segment values of the radial dose in condensed phase LiF calculated at the Instituto National de Investigaciones Nucleares (Mexico) and experimentally measured normalised (60)Co gamma-induced TL dose-response functions, f(D), carried out at the Institute of Nuclear Physics (Poland). The motivation for the calculations is to test the validity of TST in a TL system in which f(D) is not supralinear (f(D) >1) and is not significantly dependent on photon energy contrary to the behaviour of the dose-response of composite peak 5 in the glow curve of LiF:Mg,Ti (TLD-100). The calculated HCP relative efficiencies in LiF:MCP-N are 23-87% lower than the experimentally measured values, indicating a weakness in the major premise of TST which exclusively relates HCP effects to the radiation action of the secondary electrons liberated by the HCP slowing down. However, an analysis of the uncertainties involved in the TST calculations and experiments (i.e. experimental measurement of f(D) at high levels of dose, sample light self-absorption and accuracy in the estimation of D(r), especially towards the end of the HCP track) indicate that these may be too large to enable a definite conclusion. More accurate estimation of sample light self-absorption, improved measurements of f(D) and full-track Monte Carlo calculations of D(r) incorporating improvements of the low-energy electron transport are indicated in order to reduce uncertainties and enable a final conclusion. PMID:22042968

  6. Evaluation of alpha-fetoprotein (AFP) in human serum by chemiluminescence enzyme immunoassay with magnetic particles and coated tubes as solid phases.

    PubMed

    Zhang, Qianyun; Wang, Xu; Li, Zhenjia; Lin, Jin-Ming

    2009-01-12

    In this work, the monoclonal antibodies (McAbs) to alpha-fetoprotein (AFP) were immobilized on two different solid phases, i.e., magnetic particles (MP) and coated tubes (CT). Based on this, a MP based chemiluminescence enzyme immunoassay (MP-CLEIA) and a CT based CLEIA (CT-CLEIA) were proposed for the evaluation of AFP in human serum and their analytical merits were studied and compared. By detailed discussion of several performance variants, including the concentration of immobilized McAb, dilution ratio of horseradish peroxidase (HRP) labeled McAb (HRP-McAb), total assay time, substrate volume, chemiluminescent kinetics, and hook effect concentration, the advantages of MP-CLEIA became conspicuously apparent. Moreover, in the presence of MP, the catalytic activity of labeled enzyme was kept to high extent and the stability of immunoreagents was satisfied. Finally, 59 human serum samples were detected by the MP-CLEIA and a good correlation was obtained when comparing the results with that from a commercial electrochemiluminescence immunoassay kit. PMID:19084628

  7. Geochemical properties of rocks and soils in Gusev Crater, Mars: Results of the Alpha Particle X-Ray Spectrometer from Cumberland Ridge to Home Plate

    NASA Astrophysics Data System (ADS)

    Ming, D. W.; Gellert, R.; Morris, R. V.; Arvidson, R. E.; Brückner, J.; Clark, B. C.; Cohen, B. A.; d'Uston, C.; Economou, T.; Fleischer, I.; Klingelhöfer, G.; McCoy, T. J.; Mittlefehldt, D. W.; Schmidt, M. E.; Schröder, C.; Squyres, S. W.; Tréguier, E.; Yen, A. S.; Zipfel, J.

    2008-12-01

    Geochemical diversity of rocks and soils has been discovered by the Alpha Particle X-Ray Spectrometer (APXS) during Spirit's journey over Husband Hill and down into the Inner Basin from sol 470 to 1368. The APXS continues to operate nominally with no changes in calibration or spectral degradation over the course of the mission. Germanium has been added to the Spirit APXS data set with the confirmation that it occurs at elevated levels in many rocks and soils around Home Plate. Twelve new rock classes and two new soil classes have been identified at the Spirit landing site since sol 470 on the basis of the diversity in APXS geochemistry. The new rock classes are Irvine (alkaline basalt), Independence (low Fe outcrop), Descartes (outcrop similar to Independence with higher Fe and Mn), Algonquin (mafic-ultramafic igneous sequence), Barnhill (volcaniclastic sediments enriched in Zn, Cl, and Ge), Fuzzy Smith (high Si and Ti rock), Elizabeth Mahon (high Si, Ni, and Zn outcrop and rock), Halley (hematite-rich outcrop and rock), Montalva (high K, hematite-rich rock), Everett (high Mg, magnetite-rich rock), Good Question (high Si, low Mn rock), and Torquas (high K, Zn, and Ni magnetite-rich rock). New soil classes are Gertrude Weise (very high Si soil) and Eileen Dean (high Mg, magnetite-rich soil). Aqueous processes have played a major role in the formation and alteration of rocks and soils on Husband Hill and in the Inner Basin.

  8. Development of a Position Sensitive Beta and Recoil Ion Detectors for the 6He ? - ? Angular Correlation Measurement

    NASA Astrophysics Data System (ADS)

    Hong, Ran; Bagdasarova, Yelena; Garcia, Alejandro; Storm, Derek; Sternberg, Matthew; Swanson, Erik; Wauters, Frederik; Zumwalt, David; Bailey, Kevin; Leredde, Arnaud; Mueller, Peter; O'Connor, Thomas; Fléchard, Xavier; Liennard, Etienne; Knecht, Andreas; Naviliat-Cuncic, Oscar

    2014-09-01

    In order to measure the ? - ? angular correlation coefficient a and put more stringent limits on exotic tensor type weak currents, we constructed a system which detects ? particles in coincidence with recoil ions from the ?-decay of laser trapped 6He atoms. The ? particles are detected by a scintillator and a multi-wire proportional chamber (MWPC) with a capacitive charge division anode. The recoil ions are detected by a microchannel plate (MCP) with delay-line anodes. The coefficient a is extracted by fitting the coincidence data to GEANT4 based Monte Carlo simulations, which are also used to study systematic uncertainties related to the detector system. A new method of calibrating the MWPC using a cathode focusing effect will be presented. This work is supported by DOE, Office of Nuclear Physics, under contract nos. DE-AC02-06CH11357 and DE-FG02-97ER41020.

  9. Refinement of the $n-\\alpha$ and $p-\\alpha$ fish-bone potential

    E-print Network

    Smith, E; Papp, Z

    2012-01-01

    The fishbone potential of composite particles simulates the Pauli effect by nonlocal terms. We determine the $n-\\alpha$ and $p-\\alpha$ fish-bone potential by simultaneously fitting to the experimental phase shifts. We found that with a double Gaussian parametrization of the local potential can describe the $n-\\alpha$ and $p-\\alpha$ phase shifts for all partial waves.

  10. In-beam {gamma}-ray and {alpha}-decay spectroscopy of {sup 170}Ir

    SciTech Connect

    Hadinia, B.; Cederwall, B.; Wyss, R.; Johnson, A.; Lagergren, K.; Andgren, K.; Baeck, T.; Liotta, R. J.; Sandzelius, M. [Department of Physics, Royal Institute of Technology, SE-10691 Stockholm (Sweden); Joss, D. T.; Appelbe, D. E.; Barton, C. J.; Warner, D. D. [CCLRC, Daresbury Laboratory, Daresbury, Warrington, WA4 4AD (United Kingdom); Page, R. D.; Simpson, J.; Wiseman, D. R. [Oliver Lodge Laboratory, Department of Physics, University of Liverpool, Liverpool, L69 7ZE (United Kingdom); Scholey, C.; Eeckhaudt, S.; Grahn, T.; Greenlees, P. [Department of Physics, University of Jyvaeskylae, Post Office Box 35, University of Jyvaeskylae, FIN-40014 Jyvaeskylae (Finland)] (and others)

    2007-10-15

    Excited states in the highly neutron deficient odd-odd nucleus {sup 170}Ir have been investigated. The experiment was performed using the {sup 112}Sn({sup 60}Ni, pn){sup 170}Ir reaction and employing the recoil-decay tagging technique. Gamma rays were detected using the JUROGAM {gamma}-ray spectrometer and those belonging to {sup 170}Ir were selected based on recoil identification provided by the RITU gas-filled recoil separator and the GREAT spectrometer at the RITU focal plane. A partial level scheme of {sup 170}Ir is presented for the first time. New {alpha}-decay branches are assigned to {sup 170}Ir and a tentative level structure for {sup 166}Re is deduced from a study of the {alpha}-decay fine structure and the associated {alpha}-{gamma} correlations.

  11. Pulse-shape discrimination of scintillation from alpha and beta particles with liquid scintillator and Geiger-mode multipixel avalanche diodes

    Microsoft Academic Search

    I. Kreslo; I. Badhrees; S. Delaquis; A. Ereditato; S. Janos; M. Messina; U. Moser; B. Rossi; M. Zeller

    2011-01-01

    A successfull application of Geiger-mode multipixel avalanche diodes (GMAPDs) for pulse-shape discrimination in alpha-beta spectrometry using organic liquid scintillator is described in this paper. Efficient discrimination of alpha and beta components in the emission of radioactive isotopes is achieved for alpha energies above 0.3 MeV. The ultra-compact design of the scintillating detector helps to efficiently suppress cosmic-ray and ambient radiation

  12. DEVELOPMENT OF PHONON-MEDIATED CRYOGENIC PARTICLE DETECTORS WITH

    E-print Network

    California at Berkeley, University of

    DEVELOPMENT OF PHONON-MEDIATED CRYOGENIC PARTICLE DETECTORS WITH ELECTRON AND NUCLEAR RECOIL (background radiation) and nuclear recoil events (dark matter events). These detec- tors with built detectors designed to directly detect interactions with these WIMPs. These detectors are part of a new class

  13. Alpha Antihydrogen Experiment

    NASA Astrophysics Data System (ADS)

    Fujiwara, M. C.; Andresen, G. B.; Ashkezari, M. D.; Baquero-Ruiz, M.; Bertsche, W.; Bray, C. C.; Butler, E.; Cesar, C. L.; Chapman, S.; Charlton, M.; Cesar, C. L.; Fajans, J.; Friesen, T.; Gill, D. R.; Hangst, J. S.; Hardy, W. N.; Hayano, R. S.; Hayden, M. E.; Humphries, A. J.; Hydomako, R.; Jonsell, S.; Kurchaninov, L.; Lambo, R.; Madsen, N.; Menary, S.; Nolan, P.; Olchanski, K.; Olin, A.; Povilus, A.; Pusa, P.; Robicheaux, F.; Sarid, E.; Silveira, D. M.; So, C.; Storey, J. W.; Thompson, R. I.; van der Werf, D. P.; Wilding, D.; Wurtele, J. S.; Yamazaki, Y.

    2011-12-01

    ALPHA is an experiment at CERN, whose ultimate goal is to perform a precise test of CPT symmetry with trapped antihydrogen atoms. After reviewing the motivations, we discuss our recent progress toward the initial goal of stable trapping of antihydrogen, with some emphasis on particle detection techniques.

  14. Observations of short-range, high-LET recoil tracks in CR39 plastic nuclear track detector by visible light microscopy

    Microsoft Academic Search

    E. R. Benton; C. E. Johnson; J. DeWitt; N. Yasuda; E. V. Benton; M. H. Moyers; A. L. Frank

    2011-01-01

    Using standard visible light microscopy, we are able to observe particle tracks produced by <10 ?m range target fragment recoils in CR-39 plastic nuclear track detector (PNTD) following short chemical etching (bulk etch B ?1 ?m). In accelerator irradiations, targets of varying composition, including a number of elemental targets of high Z, were exposed in contact with layers of CR-39 PNTD to

  15. Detection of alpha radiation in a beta radiation field

    DOEpatents

    Mohagheghi, Amir H. (Albuquerque, NM); Reese, Robert P. (Edgewood, NM)

    2001-01-01

    An apparatus and method for detecting alpha particles in the presence of high activities of beta particles utilizing an alpha spectrometer. The apparatus of the present invention utilizes a magnetic field applied around the sample in an alpha spectrometer to deflect the beta particles from the sample prior to reaching the detector, thus permitting detection of low concentrations of alpha particles. In the method of the invention, the strength of magnetic field required to adequately deflect the beta particles and permit alpha particle detection is given by an algorithm that controls the field strength as a function of sample beta energy and the distance of the sample to the detector.

  16. Treatment of HER2-Expressing Breast Cancer and Ovarian Cancer Cells With Alpha Particle-Emitting {sup 227}Th-Trastuzumab

    SciTech Connect

    Heyerdahl, Helen; Krogh, Cecilie [Department of Radiation Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo (Norway); Borrebaek, Jorgen [Algeta ASA, Kjelsas, Oslo (Norway); Larsen, Asmund [Algeta ASA, Kjelsas, Oslo (Norway); Department of Radiation Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo (Norway); Dahle, Jostein, E-mail: jostein.dahle@rr-research.n [Department of Radiation Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo (Norway)

    2011-02-01

    Purpose: To evaluate the cytotoxic effects of low-dose-rate alpha particle-emitting radioimmunoconjugate {sup 227}Th-p-isothiocyanato-benzyl-DOTA-trastuzumab ({sup 227}Th-trastuzumab [where DOTA is 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]) internalized by breast and ovarian cancer cell lines in order to assess the potential of {sup 227}Th-trastuzumab as a therapeutic agent against metastatic cancers that overexpress the HER2 oncogene. Methods and Materials: Clonogenic survival and cell growth rates of breast cancer cells treated with {sup 227}Th-trastuzumab were compared with rates of cells treated with nonbinding {sup 227}Th-rituximab, cold trastuzumab, and X-radiation. Cell growth experiments were also performed with ovarian cancer cells. Cell-associated radioactivity was measured at several time points, and the mean radiation dose to cells was calculated. Results: SKBR-3 cells got 50% of the mean absorbed radiation dose from internalized activity and 50% from cell surface-bound activity, while BT-474 and SKOV-3 cells got 75% radiation dose from internalized activity and 25% from cell surface-bound activity. Incubation of breast cancer cells with 2.5 kBq/ml {sup 227}Th-trastuzumab for 1 h at 4{sup o}C, followed by washing, resulted in mean absorbed radiation doses of 2 to 2.5 Gy. A dose-dependent inhibition of cell growth and an increase in apoptosis were induced in all cell lines. Conclusions: Clinically relevant activity concentrations of {sup 227}Th-trastuzumab induced a specific cytotoxic effect in three HER2-expressing cell lines. The cytotoxic effect of {sup 227}Th-trastuzumab was higher than that of single-dose X-radiation (relative biological effectiveness = 1.2). These results warrant further studies of treatment of breast cancer and ovarian cancer with {sup 227}Th-trastuzumab.

  17. Submillisecond Elastic Recoil Reveals Molecular Origins of Fibrin Fiber Mechanics

    PubMed Central

    Hudson, Nathan E.; Ding, Feng; Bucay, Igal; O’Brien, E. Timothy; Gorkun, Oleg V.; Superfine, Richard; Lord, Susan T.; Dokholyan, Nikolay V.; Falvo, Michael R.

    2013-01-01

    Fibrin fibers form the structural scaffold of blood clots. Thus, their mechanical properties are of central importance to understanding hemostasis and thrombotic disease. Recent studies have revealed that fibrin fibers are elastomeric despite their high degree of molecular ordering. These results have inspired a variety of molecular models for fibrin’s elasticity, ranging from reversible protein unfolding to rubber-like elasticity. An important property that has not been explored is the timescale of elastic recoil, a parameter that is critical for fibrin’s mechanical function and places a temporal constraint on molecular models of fiber elasticity. Using high-frame-rate imaging and atomic force microscopy-based nanomanipulation, we measured the recoil dynamics of individual fibrin fibers and found that the recoil was orders of magnitude faster than anticipated from models involving protein refolding. We also performed steered discrete molecular-dynamics simulations to investigate the molecular origins of the observed recoil. Our results point to the unstructured ?C regions of the otherwise structured fibrin molecule as being responsible for the elastic recoil of the fibers. PMID:23790375

  18. Calculation of recoil implantation profiles using known range statistics

    NASA Technical Reports Server (NTRS)

    Fung, C. D.; Avila, R. E.

    1985-01-01

    A method has been developed to calculate the depth distribution of recoil atoms that result from ion implantation onto a substrate covered with a thin surface layer. The calculation includes first order recoils considering projected range straggles, and lateral straggles of recoils but neglecting lateral straggles of projectiles. Projectile range distributions at intermediate energies in the surface layer are deduced from look-up tables of known range statistics. A great saving of computing time and human effort is thus attained in comparison with existing procedures. The method is used to calculate recoil profiles of oxygen from implantation of arsenic through SiO2 and of nitrogen from implantation of phosphorus through Si3N4 films on silicon. The calculated recoil profiles are in good agreement with results obtained by other investigators using the Boltzmann transport equation and they also compare very well with available experimental results in the literature. The deviation between calculated and experimental results is discussed in relation to lateral straggles. From this discussion, a range of surface layer thickness for which the method applies is recommended.

  19. Angular distribution in alpha-induced fission of 232Th and 238U

    Microsoft Academic Search

    T. Datta; S. P. Dange; H. Naik; S. B. Manohar

    1993-01-01

    The angular distribution of fission products has been measured as a function of mass asymmetry in the fissioning systems 232Th(alpha39.1MeV, f), 238U(alpha29.0MeV, f), and 238U(alpha39.1MeV, f) using the recoil-catcher technique and off-line gamma spectrometry. The present data have been analyzed along with similar data reported earlier by us for 232Th(alpha29MeV, f) and 233U(alpha29MeV, f) and the literature data on mass-averaged

  20. Alpha-particle spectrometer experiment

    NASA Technical Reports Server (NTRS)

    Gorenstein, P.; Bjorkholm, P.

    1972-01-01

    Observation of lunar radon emanation during the Apollo 15 and 16 missions shows the existence of areas with locally high emanation rates. The most conspicuous Rn-222 feature found in the data analysis is a region that includes Aristarchus Crater. The excess emanating power of the Aristarchus region may be an indication of internal activity at that site. There are regions with anomalously high rates of Po-210 activity, which indicates transient phenomena involving the release of Rn-222 gas from certain areas of the moon.

  1. First detection of tracks of radon progeny recoils by MIMAC

    E-print Network

    Riffard, Q; Bosson, G; Bourrion, O; Descombes, T; Fourel, C; Guillaudin, O; Muraz, J -F; Colas, P; Ferrer-Ribas, E; Giomataris, I; Busto, J; Fouchez, D; Tao, C; Lebreton, L; Maire, D

    2015-01-01

    The MIMAC experiment is a $\\mu$-TPC matrix project for directional dark matter search. Directional detection is a strategy based on the measurement of the WIMP flux anisotropy due to the solar system motion with respect to the dark matter halo. The main purpose of MIMAC project is the measurement of the energy and the direction of nuclear recoils in 3D produced by elastic scattering of WIMPs. Since June 2012 a bi-chamber prototype is operating at the Modane underground laboratory. In this paper, we report the first ionization energy and 3D track observations of nuclear recoils produced by the radon progeny. This measurement shows the capability of the MIMAC detector and opens the possibility to explore the low energy recoil directionality signature.

  2. First detection of tracks of radon progeny recoils by MIMAC

    E-print Network

    Q. Riffard; D. Santos; G. Bosson; O. Bourrion; T. Descombes; C. Fourel; O. Guillaudin; J. -F. Muraz; P. Colas; E. Ferrer-Ribas; I. Giomataris; J. Busto; D. Fouchez; C. Tao; L. Lebreton; D. Maire

    2015-04-22

    The MIMAC experiment is a $\\mu$-TPC matrix project for directional dark matter search. Directional detection is a strategy based on the measurement of the WIMP flux anisotropy due to the solar system motion with respect to the dark matter halo. The main purpose of MIMAC project is the measurement of the energy and the direction of nuclear recoils in 3D produced by elastic scattering of WIMPs. Since June 2012 a bi-chamber prototype is operating at the Modane underground laboratory. In this paper, we report the first ionization energy and 3D track observations of nuclear recoils produced by the radon progeny. This measurement shows the capability of the MIMAC detector and opens the possibility to explore the low energy recoil directionality signature.

  3. Pulse-shape discrimination of scintillation from alpha and beta particles with liquid scintillator and Geiger-mode multipixel avalanche diodes

    E-print Network

    Kreslo, I; Delaquis, S; Ereditato, A; Janos, S; Messina, M; Moser, U; Rossi, B; Zeller, M

    2011-01-01

    A successfull application of Geiger-mode multipixel avalanche diodes (GMAPDs) for pulse-shape discrimination in alpha-beta spectrometry using organic liquid scintillator is described in this paper. Efficient discrimination of alpha and beta components in the emission of radioactive isotopes is achieved for alpha energies above 0.3 MeV. The ultra-compact design of the scintillating detector helps to efficiently suppress cosmic-ray and ambient radiation background. This approach allows construction of hand-held robust devices for monitoring of radioactive contamination in various environmental conditions.

  4. Pulse-shape discrimination of scintillation from alpha and beta particles with liquid scintillator and Geiger-mode multipixel avalanche diodes

    NASA Astrophysics Data System (ADS)

    Kreslo, I.; Badhrees, I.; Delaquis, S.; Ereditato, A.; Janos, S.; Messina, M.; Moser, U.; Rossi, B.; Zeller, M.

    2011-07-01

    A successfull application of Geiger-mode multipixel avalanche diodes (GMAPDs) for pulse-shape discrimination in alpha-beta spectrometry using organic liquid scintillator is described in this paper. Efficient discrimination of alpha and beta components in the emission of radioactive isotopes is achieved for alpha energies above 0.3 MeV. The ultra-compact design of the scintillating detector helps to efficiently suppress cosmic-ray and ambient radiation background. This approach allows construction of hand-held robust devices for monitoring of radioactive contamination in various environmental conditions.

  5. Stopping Power of Au for Ti Using Elastic Recoil Technique

    SciTech Connect

    Linares, R.; Freire, J. A.; Ribas, R. V.; Medina, N. H.; Oliveira, J. R. B.; Seale, W. A.; Cybulska, E. W.; Wiedemann, K. T.; Allegro, P. R.; Toufen, D. L. [Instituto de Fisica da Universidade de Sao Paulo, C.P. 66318, 05317-970, S. Paulo, SP (Brazil)

    2009-06-03

    The slowing down of heavy ions in matter is still not well understood especially at low energies (<0.5 MeV/u). In this contribution we present new experimental data for the stopping power of Au for Ti ions using an elastic recoil technique where a heavy-ion beam at low energies is produced by elastic scattering of an energetic primary beam imping on a thin target. Atoms from the target recoil at low energies. We compare our experimental data with previous data and with semi-empirical and theoretical models.

  6. Alpha detection on moving surfaces

    SciTech Connect

    MacArthur, D. [Los Alamos National Lab., NM (United States); Orr, C.; Luff, C. [BNFL Instruments Ltd., Sellafield (United Kingdom)

    1998-12-01

    Both environmental restoration (ER) and decontamination and decommissioning (D and D) require characterization of large surface areas (walls, floors, in situ soil, soil and rubble on a conveyor belt, etc.) for radioactive contamination. Many facilities which have processed alpha active material such as plutonium or uranium require effective and efficient characterization for alpha contamination. Traditional methods for alpha surface characterization are limited by the short range and poor penetration of alpha particles. These probes are only sensitive to contamination located directly under the probe. Furthermore, the probe must be held close to the surface to be monitored in order to avoid excessive losses in the ambient air. The combination of proximity and thin detector windows can easily cause instrument damage unless extreme care is taken. The long-range alpha detection (LRAD) system addresses these problems by detecting the ions generated by alpha particles interacting with ambient air rather than the alpha particle directly. Thus, detectors based on LRAD overcome the limitations due to alpha particle range (the ions can travel many meters as opposed to the several-centimeter alpha particle range) and penetrating ability (an LRAD-based detector has no window). Unfortunately, all LRAD-based detectors described previously are static devices, i.e., these detectors cannot be used over surfaces which are continuously moving. In this paper, the authors report on the first tests of two techniques (the electrostatic ion seal and the gridded electrostatic LRAD detector) which extend the capabilities of LRAD surface monitors to use over moving surfaces. This dynamic surface monitoring system was developed jointly by Los Alamos National Laboratory and at BNFL Instruments. All testing was performed at the BNFL Instruments facility in the UK.

  7. Alpha Channeling in Rotating Plasma with Stationary Waves

    SciTech Connect

    A. Fetterman and N.J. Fisch

    2010-02-15

    An extension of the alpha channeling effect to supersonically rotating mirrors shows that the rotation itself can be driven using alpha particle energy. Alpha channeling uses radiofrequency waves to remove alpha particles collisionlessly at low energy. We show that stationary magnetic fields with high n? can be used for this purpose, and simulations show that a large fraction of the alpha energy can be converted to rotation energy.

  8. Test modeling and parameter identification of a gun magnetorheological recoil damper

    Microsoft Academic Search

    Hu Hongsheng; Wang Jiong; Qian Suxiang; Jiang Xuezheng

    2009-01-01

    Since its performance requirements of gun recoil mechanism have been continuously increased, this paper was explored and aimed at its dynamic model and parameter identification of a new type of gun magnetorheological recoil damper. Combining with its recoil resistance rule and stroke requirements of the 37mm caliber gun, a long-stroke magnetorheological recoil damper was developed. Using the developed hardware-in-the-loop simulation

  9. On alpha heating in toroidal devices

    Microsoft Academic Search

    G. H. Miley

    1979-01-01

    Studies of the alpha particle losses and heating profiles for an alpha-heated TFTR-sized tokamak and a small field-reversed mirror reactor (FRM) are presented. The slowing-down and drift of high-energy alpha particles, including detailed orbital effects, is approximated for tokamak geometry using the SYMALF multi-energy-angle code. Results of the calculation for a beam-driven TFTR-type plasma indicate that, except for the center

  10. Dynamics of kinematically constrained bimolecular reactions having constant product recoil energy

    E-print Network

    Zare, Richard N.

    Dynamics of kinematically constrained bimolecular reactions having constant product recoil energy reactions in which the product recoil energy is assumed constant (CPR approximation). It is further assumed-shaped, peaking at the vibrational level with an energy equal to the reaction exoergicity minus the product recoil

  11. H + D2 Reaction Dynamics in the Limit of Low Product Recoil Energy J. Aldegunde,

    E-print Network

    Zare, Richard N.

    H + D2 Reaction Dynamics in the Limit of Low Product Recoil Energy J. Aldegunde, D. Herraez increases and the corresponding energy available for product recoil decreases. This behavior was attributed, whose influence becomes more significant as the recoil energy of the products tends to zero, which

  12. Diesel exhaust particles induce the over expression of tumor necrosis factor-alpha (TNF-alpha) gene in alvelor machrophage and failed to induce apoptosis through activation of nuclear factor-kappaB (NF-kappaB)

    EPA Science Inventory

    Exposure to particulate matter (PM2.5-10), including diesel exhaust particles (DEP) has been reported to induce lung injury and exacerbation of asthma and chronic obstructive pulmonary disease. Alveolar macrophages play a major role in the lung's response to inhaled particles and...

  13. Dynamic simulation of the recoil mechanism on artillery weapons

    Microsoft Academic Search

    T. Y. Lin; H. C. Ping; T. Y. Yang; C. T. Chan; C. C. Yang

    Summary The artillery weapons have been developed from the thirteenth century to the present. Generally, it contains a gun body and a gun mount. The gun body consists of a barrel, a breech, a breechblock, and a muzzle brake. In addition,thegun mount is composed of recoil mechanisms, elevating mechanisms, traversing mechanisms, and supporting parts. Among these parts, the muzzle brake

  14. Distribution of Recoil Nucleus in Pair Production by Photons

    Microsoft Academic Search

    R. Jost; J. M. Luttinger; M. Slotnick

    1950-01-01

    The angular and momentum distribution of the recoil nucleus in pair production by a photon is calculated covariantly by a method which utilizes the unitarity of the S matrix. The results are in disagreement with a recent experiment, particularly for small angles and high momentum transfers. The exact total cross section for pair creation is also given.

  15. Report on the HERMES Recoil Detector Sergey Yaschenko

    E-print Network

    Detector 2 layers of double-sided silicon strip sensors located in beam vacuum Strips: pitch=758 m, 300m hydrogen target: 38 Mio DIS (41.000 DVCS) Unpolarized deuterium target: 10 Mio DIS (7.500 DVCS) Two beam hydrogen and deuterium targets #12;S. Yaschenko, Report on the HERMES Recoil Detector 7 Silicon Strip

  16. In-beam studies of proton emitters using the Recoil-Decay Tagging method

    SciTech Connect

    Seweryniak, D.; Woods, P. J.; Ressler, J.; Davids, C. N.; Heinz, A.; Sonzogni, A.; Uusitalo, J.; Walters, W. B.; Caggiano, J.; Carpenter, M. P.; Cizewski, J. A.; Davinson, T.; Ding, K. Y.; Fotiades, N.; Garg, U.; Janssens, R. V. F.; Khoo, T.-L.; Kondev, F.; Lauritsen, T.; Lister, C. J.; Reiter, P.; Shergur, J.; Wiedenhoever, I.

    2000-01-19

    The last five years have witnessed a rapid increase in the volume of data on proton decaying nuclei. The path was led by decay studies with recoil mass separators equipped with double-sided Si strip detectors. The properties of many proton-decaying states were deduced, which triggered renewed theoretical interest in the process of proton decay. The decay experiments were closely followed by in-beam {gamma}-ray studies which extended one's knowledge of high-spin states of proton emitters. The unparalleled selectivity of the Recoil-Decay Tagging method combined with the high efficiency of large arrays of Ge detectors allowed, despite small cross sections and overwhelming background from strong reaction channels, the observation of excited states in several proton emitters. Recently, in-beam studies of the deformed proton emitters {sup 141}Ho and {sup 131}Eu have been performed with the GAMMASPHERE array of Ge detectors and the Fragment Mass Analyzer at ATLAS. Evidence was found for rotational bands in {sup 141}Ho and {sup 131}Eu. The deformations and the single-particle configurations proposed for the proton emitting states from the earlier proton-decay studies were confronted with the assignments deduced based on the in-beam data. It should be noted that the cross section for populating {sup 131}Eu is only about 50 nb, and it represents the weakest channel ever studied in an in-beam experiment.

  17. Pulse-shape discrimination between electron and nuclear recoils in a NaI(Tl) crystal

    E-print Network

    H. S. Lee; G. Adhikari; P. Adhikari; S. Choi; I. S. Hahn; E. J. Jeon; H. W. Joo; W. G. Kang; G. B. Kim; H. J. Kim; H. O. Kim; K. W. Kim; N. Y. Kim; S. K. Kim; Y. D. Kim; Y. H. Kim; J. H. Lee; M. H. Lee; D. S. Leonard; J. Li; S. Y. Oh; S. L. Olsen; H. K. Park; H. S. Park; K. S. Park; J. H. Shim; J. H. So

    2015-03-18

    We report on the response of a high light-output NaI(Tl) crystal to nuclear recoils induced by neutrons from an Am-Be source and compare the results with the response to electron recoils produced by Compton scattered 662 keV $\\gamma$-rays from a $^{137}$Cs source. The measured pulse-shape discrimination (PSD) power of the NaI(Tl) crystal is found to be significantly improved because of the high light output of the NaI(Tl) detector. We quantify the PSD power with a quality factor and estimate the sensitivity to the interaction rate for weakly interacting massive particles (WIMPs) with nucleons, and the result is compared with the annual modulation amplitude observed by the DAMA/LIBRA experiment. The sensitivity to spin-independent WIMP-nucleon interactions based on 100 kg$\\cdot$year of data from NaI detectors is estimated with simulated experiments, using the standard halo model.

  18. The mechanics of elastic loading and recoil in anuran jumping.

    PubMed

    Astley, Henry C; Roberts, Thomas J

    2014-12-15

    Many animals use catapult mechanisms to produce extremely rapid movements for escape or prey capture, resulting in power outputs far beyond the limits of muscle. In these catapults, muscle contraction loads elastic structures, which then recoil to release the stored energy extremely rapidly. Many arthropods employ anatomical 'catch mechanisms' to lock the joint in place during the loading period, which can then be released to allow joint motion via elastic recoil. Jumping vertebrates lack a clear anatomical catch, yet face the same requirement to load the elastic structure prior to movement. There are several potential mechanisms to allow loading of vertebrate elastic structures, including the gravitational load of the body, a variable mechanical advantage, and moments generated by the musculature of proximal joints. To test these hypothesized mechanisms, we collected simultaneous 3D kinematics via X-ray Reconstruction of Moving Morphology (XROMM) and single-foot forces during the jumps of three Rana pipiens. We calculated joint mechanical advantage, moment and power using inverse dynamics at the ankle, knee, hip and ilio-sacral joints. We found that the increasing proximal joint moments early in the jump allowed for high ankle muscle forces and elastic pre-loading, and the subsequent reduction in these moments allowed the ankle to extend using elastic recoil. Mechanical advantage also changed throughout the jump, with the muscle contracting against a poor mechanical advantage early in the jump during loading and a higher mechanical advantage late in the jump during recoil. These 'dynamic catch mechanisms' serve to resist joint motion during elastic loading, then allow it during elastic recoil, functioning as a catch mechanism based on the balance and orientation of forces throughout the limb rather than an anatomical catch. PMID:25520385

  19. ALPHA OMEGA ALPHA National Honor Medical Society

    E-print Network

    12/7/2011 1 ALPHA OMEGA ALPHA National Honor Medical Society www.alphaomegaalpha.org AA and Leadership William Root The Alpha Omega Alpha honor medical society was initially organized in 1902/community service. AA and Medical Professionalism "Be Worthy to Serve the Suffering" #12;Alpha Omega Alpha Honor

  20. Streptavidin in antibody pretargeting. 5. chemical modification of recombinant streptavidin for labeling with the alpha-particle-emitting radionuclides 213Bi and 211At.

    PubMed

    Wilbur, D Scott; Hamlin, Donald K; Chyan, Ming-Kuan; Brechbiel, Martin W

    2008-01-01

    We are investigating the use of recombinant streptavidin (rSAv) as a carrier molecule for the short-lived alpha-particle-emitting radionuclides 213Bi ( t 1/2 = 45.6 min) and 211At ( t 1/2 = 7.21 h) in cancer therapy. To utilize rSAv as a carrier, it must be modified in a manner that permits rapid chelation or bonding with these short-lived radionuclides and also modified in a manner that diminishes its natural propensity for localization in the kidney. Modification for labeling with (213)Bi was accomplished by conjugation of rSAv with the DTPA derivative p-isothiocyanato-benzyl-CHX-A'' (CHX-A''), 3a. Modification for direct labeling with 211At was accomplished by conjugation of rSAv with an isothiocyanatophenyl derivative of a nido-carborane (nCB), 3b, or an isothiocyanatophenyl-dPEG/decaborate(2-) derivative, 3c. After conjugation of the chelating or bonding moiety, rSAv was further modified by reaction with an excess (50-100 equivalents) of succinic anhydride. Succinylation of the lysine amines has previously been shown to greatly diminish kidney localization. rSAv modified by conjugation with 3a and succinylated rapidly radiolabeled with 213Bi (<5 min), providing a 72% isolated yield. 211At labeling of modified rSAv was accomplished in aqueous solution using chloramine-T as the oxidant. Astatination of rSAv conjugated with 3b and succinylated occurred very rapidly (<1 min), providing a 50% isolated radiochemical yield. Astatination of rSAv conjugated with 3c and succinylated was also very rapid (<1 min) providing 66-71% isolated radiochemical yields. Astatination of succinylated rSAv, 2a, which did not have conjugated borane cage moieties, resulted in a much lower radiolabeling yield (18%). The 213Bi or 211At-labeled modified rSAv preparations were mixed with the corresponding 125 I-labeled rSAv, and dual-label in vivo distributions were obtained in athymic mice. The in vivo data show that 213Bi-labeled succinylated rSAv [ 213Bi] 6a has tissue concentrations similar to those of 125 I-labeled modified rSAv [ 125 I] 6b, suggesting that (213)Bi is quite stable toward release from the chelate in vivo. In vivo data also indicate that the (211)At-labeled rSAv conjugated with 3b or 3c and succinylated are stable to in vivo deastatination, whereas succinylated rSAv lacking a boron cage moiety is subject to some deastatination. The modified rSAv conjugated with nido-carborane derivative 3b has a higher retention in many tissues than rSAv without the carborane conjugated. Interestingly, the rSAv conjugated with 3c, which also contains an m-dPEG 12 moiety, has significantly decreased concentrations in blood and other tissues when compared with those of direct-labeled rSAv, suggesting that it may be a good candidate for further study. In conclusion, rSAv that has been modified with CHX-A'' and succinylated (i.e., 5a) may be useful as a carrier of 213Bi. The encouraging results obtained with the PEGylated decaborate(2-) derivative 3c and succinylated (i.e., 5c) suggests that its further study as a carrier of 211At in pretargeting protocols is warranted. PMID:18072725

  1. A recoil resilient lumen support, design, fabrication and mechanical evaluation

    NASA Astrophysics Data System (ADS)

    Mehdizadeh, Arash; Ali, Mohamed Sultan Mohamed; Takahata, Kenichi; Al-Sarawi, Said; Abbott, Derek

    2013-06-01

    Stents are artificial implants that provide scaffolding to a cavity inside the body. This paper presents a new luminal device for reducing the mechanical failure of stents due to recoil, which is one of the most important issues in stenting. This device, which we call a recoil-resilient ring (RRR), is utilized standalone or potentially integrated with existing stents to address the problem of recoil. The proposed structure aims to minimize the need for high-pressure overexpansion that can induce intra-luminal trauma and excess growth of vascular tissue causing later restenosis. The RRR is an overlapped open ring with asymmetrical sawtooth structures that are intermeshed. These teeth can slide on top of each other, while the ring is radially expanded, but interlock step-by-step so as to keep the final expanded state against compressional forces that normally cause recoil. The RRRs thus deliver balloon expandability and, when integrated with a stent, bring both radial rigidity and longitudinal flexibility to the stent. The design of the RRR is investigated through finite element analysis (FEA), and then the devices are fabricated using micro-electro-discharge machining of 200-µm-thick Nitinol sheet. The standalone RRR is balloon expandable in vitro by 5-7 Atm in pressure, which is well within the recommended in vivo pressure ranges for stenting procedures. FEA compression tests indicate 13× less reduction of the cross-sectional area of the RRR compared with a typical stainless steel stent. These results also show perfect elastic recovery of the RRR after removal of the pressure compared to the remaining plastic deformations of the stainless steel stent. On the other hand, experimental loading tests show that the fabricated RRRs have 2.8× radial stiffness compared to a two-column section of a commercial stent while exhibiting comparable elastic recovery. Furthermore, testing of in vitro expansion in a mock artery tube shows around 2.9% recoil, approximately 5-11× smaller than the recoil reported for commercial stents. These experimental results demonstrate the effectiveness of the device design for the targeted luminal support and stenting applications.

  2. Use of the gas-filled-magnet technique for particle identification at low energies

    SciTech Connect

    Rehm, K.K.; Jiang, C.L.; Paul, M. [Hebrew Univ., Jerusalem (Israel)

    1995-08-01

    Reaction studies of interest to astrophysics with radioactive ion beams will be done mainly in inverse reaction kinematics, i.e., heavy particles bombarding a hydrogen target. The low energy of the outgoing heavy reaction products makes particle identification with respect to mass and nuclear charge a major challenge. For the planned {sup 18}F(p,{alpha}) experiment one expects five different types of particles in the outgoing channels: {sup 18}F and {sup 18}O (from elastic scattering of {sup 18}F and {sup 18}O on {sup 12}C), {sup 15}O and {sup 15}N (from the {sup 18}F and {sup 18}O induced (p,{alpha}) reactions) and {sup 12}C recoils from the polypropylene target. While mass determination can be achieved easily by time-of-flight (TOF) measurements, a determination of the nuclear charge presents a challenge, especially if the energy of the particles is below 500 keV/u. We studied the gas-filled magnet technique for Z-identification of light ions between Z = 6-9. In a gas-filled magnet the particles move with an average charge state {bar q} which in one parameterization is given by {bar q} = Z ln(avZ{sup {alpha}})/ln(bZ{sup {beta}}) where Z is the nuclear charge of the ions and v their velocity. Introducing into the expression for the magnetic rigidity B{rho} = mv/{bar q} results in a Z dependence of B{rho} which is valid to very low velocities. As a magnet we used the Enge split-pole spectrograph which was filled with nitrogen gas at a pressure of 0.5 Torr. The particles were detected in the focal plane with a 50 x 10 cm{sup 2} parallel-grid-avalanche counter which measured TOF and magnetic rigidity. The mass and Z separation was tested with {sup 13}C and {sup 18}O beams at energies of about 600 keV/u and recoil particles ranging from {sup 12}C to {sup 19}F. The Z-separation obtained at these energies was {triangle}Z/Z = 0.28 which is sufficient to separate individual elements for Z < 10.

  3. Recoil Decay Tagging Study Of Transitional Proton Emitters 145,146,147Tm

    SciTech Connect

    Robinson, A.P.; Woods, P.J.; Davinson, T.; Liu, Z. [University of Edinburgh, Edinburgh (United Kingdom); Davids, C.N.; Seweryniak, D.; Carpenter, M.P.; Hammond, N.; Janssens, R.V.F.; Mukherjee, G.; Sinha, S. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Blank, B. [CEN Bordeaux-Gradignan, IN2P3-CNRS (France); Freeman, S.J. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); University of Manchester, Manchester (United Kingdom); Hoteling, N.; Shergur, J.; Walters, W.B. [University of Maryland, College Park, Maryland 20742 (United States); Scholey, C. [University of Jyvaeskylae, Jyvaeskylae (Finland); Sonzogni, A.A. [NNDS Brookhaven National Laboratory, Upton, New York 11937 (United States); Woehr, A. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); University of Maryland, College Park, Maryland 20742 (United States)

    2005-04-05

    Gamma rays from the transitional proton emitting nuclei 145,146,147Tm have been observed using the recoil-decay tagging technique. The ground state band of 147Tm was confirmed and extended and the unfavoured signature sequence was observed. A ground state rotational band with properties of a decoupled h11/2 band was observed in 145Tm. In addition coincidences between the proton fine structure line and the 2+{yields}0+ {gamma}-ray transition in 144Er were detected at the focal plane of the FMA. This is the first time that coincidences between proton radioactive decays and {gamma} rays have been seen. The particle decay of 146Tm has been measured with improved statistics and a rotational band similar to 147Tm has been observed.

  4. A recoil proton detector using cylindrical multiwire proportional chambers with delay-line cathode readouts

    NASA Astrophysics Data System (ADS)

    Ambats, I.; Arenton, M. W.; Ayres, D. S.; Dawson, J.; Diebold, R.; May, E. N.; Sauer, J. R.; Walschon, E.; Wicklund, A. B.; Swallow, E. C.

    1980-08-01

    We have built and operated a set of two low-mass cylindrical multiwire proportional chambers to detect recoil protons emerging from a liquid hydrogen target. The chambers were 20 and 40 cm in diameter and ˜ 50 cm long, with axes and anode wires parallel to the beam direction. "Magic gas" was used to ensure that avalanches measured the points of closest approach for particle trajectories, which were often at small angles to the anode wires. Azimuthal coordinates were provided by the 2 mm-spaced anode wires (at positive high voltage); longitudinal coordinates were obtained from 4 mm-wide circular cathode strips perpendicular to the anode wires, read out by 12 nsec/cm delay lines. For single-track events, resolutions better than 1 mm rms were obtained for both coordinates.

  5. Neutron scattering facility for the calibration of the response to nuclear recoils

    NASA Astrophysics Data System (ADS)

    Jochum, J.; Chambon, B.; Drain, D.; von Feilitzsch, F.; Gascon, J.; Huber, M.; Jagemann, T.; de Jésus, M.; Lachenmaier, T.; Lanfranchi, J.-C.; Martineau, O.; Potzel, W.; Rüdig, A.; Schnagl, J.; Simon, E.; Stark, M.; Stern, M.; Wulandari, H.

    2002-02-01

    A possibility to search for elementary particles as dark matter candidates is to detect elastic scattering with cryogenic detectors. For the interpretation of the data one has to determine the detector response to nuclear recoils, the so-called quenching factors. They can differ for the heat-, for the scintillation- and for the ionization-signal and can be measured by scattering of neutrons. The CRESST- and the EDELWEISS-collaborations have set up a neutron scattering facility for cryogenic detectors at the tandem-accelerator of the Munich `Maier-Leibniz-Labor.' The scattering angle and the time-of-flight of the neutrons are measured by an array of liquid scintillator cells. The pulsed high energy (11 MeV) neutron beam is created by nuclear reaction of a 11B on a H2-gas target. The set-up and the results of first tests are presented. .

  6. Development of a new Recoil Distance Technique using Coulomb Excitation in Inverse Kinematics

    NASA Astrophysics Data System (ADS)

    Rother, Wolfram; Dewald, Alfred; Ilie, Gabriela; Pissulla, Thomas; Melon, Barbara; Jolie, Jan; Pascovici, Gheorghe; Iwasaki, Hironori; Hackstein, Matthias; Zell, Karl-Oskar; Julin, Rauno; Jones, Peter; Greenlees, Paul; Rahkila, Panu; Uusitalo, Juha; Scholey, Cath; Harissopulos, Sotirios; Lagoyannis, Anastasios; Konstantinopoulos, Theodore; Grahn, Tuomas; Balabanski, Dimiter; Petkov, Pavel

    2009-01-01

    We report on an experiment using Coulomb excitation in inverse kinematics in combination with the plunger technique for measuring lifetimes of excited states of the projectiles. Aside from the investigation of E(5) features in 128Xe, the aim was to explore the special features of such experiments which are also suited to be used with radioactive beams. The measurement was performed at the JYFL with the Köln coincidence plunger device and the JUROGAM spectrometer using a 128Xe beam impinging on a natFe target at a beam energy of 525 MeV. Recoils were detected by means of 32 solar cells placed at extreme forward angles. Particle-gated ?-singles and ??-coincidences were measured at different target-degrader distances. Details of the experiment and first results are presented.

  7. Recoiling black holes: electromagnetic signatures, candidates, and astrophysical implications

    E-print Network

    Komossa, S

    2012-01-01

    Supermassive black holes (SMBHs) may not always reside right at the centers of their host galaxies. This is a prediction of numerical relativity simulations, which imply that the newly formed single SMBH, after binary coalescence in a galaxy merger, can receive kick velocities up to several 1000 km/s due to anisotropic emission of gravitational waves. Long-lived oscillations of the SMBHs in galaxy cores, and in rare cases even SMBH ejections from their host galaxies, are the consequence. Observationally, accreting recoiling SMBHs would appear as quasars spatially and/or kinematically off-set from their host galaxies. The presence of the "kicks" has a wide range of astrophysical implications which only now are beginning to be explored, including consequences for black hole and galaxy assembly at the epoch of structure formation, black hole feeding, and unified models of Active Galactic Nuclei (AGN). Here, we review the observational signatures of recoiling SMBHs and the properties of the first candidates which...

  8. Time-of-flight direct recoil ion scattering spectrometer

    DOEpatents

    Krauss, A.R.; Gruen, D.M.; Lamich, G.J.

    1994-09-13

    A time-of-flight direct recoil and ion scattering spectrometer beam line is disclosed. The beam line includes an ion source which injects ions into pulse deflection regions and separated by a drift space. A final optics stage includes an ion lens and deflection plate assembly. The ion pulse length and pulse interval are determined by computerized adjustment of the timing between the voltage pulses applied to the pulsed deflection regions. 23 figs.

  9. Imaging the ionization track of alpha recoils for the directional detection of weapons grade plutonium

    E-print Network

    Koch, William Lawrence

    2013-01-01

    Since the dawn of the nuclear weapons era, political, military, and scientific leaders around the world have been working to contain the proliferation of Special Nuclear Material and explosively fissile material. This paper ...

  10. Revealing Compressed Stops Using High-Momentum Recoils

    E-print Network

    Macaluso, Sebastian; Shih, David; Tweedie, Brock

    2015-01-01

    Searches for supersymmetric top quarks at the LHC have been making great progress in pushing sensitivity out to higher mass, but are famously plagued by gaps in coverage around lower-mass regions where the decay phase space is closing off. Within the common stop-NLSP / neutralino-LSP simplified model, the line in the mass plane where there is just enough phase space to produce an on-shell top quark remains almost completely unconstrained. Here, we show that is possible to define searches capable of probing a large patch of this difficult region, with S/B ~ 1 and significances often well beyond 5 sigma. The basic strategy is to leverage the large energy gain of LHC Run 2, leading to a sizable population of stop pair events recoiling against a hard jet. The recoil not only re-establishes a MET signature, but also leads to a distinctive anti-correlation between the MET and the recoil jet transverse vectors when the stops decay all-hadronically. Accounting for jet combinatorics, backgrounds, and imperfections in ...

  11. Anatomy of the binary black hole recoil: A multipolar analysis

    SciTech Connect

    Schnittman, Jeremy D.; Buonanno, Alessandra [Maryland Center for Fundamental Physics, Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Meter, James R. van [Gravitational Astrophysics Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771 (United States); Center for Space Science and Technology, University of Maryland Baltimore County, Physics Department, 1000 Hilltop Circle, Baltimore, Maryland 21250 (United States); Baker, John G.; Centrella, Joan; Kelly, Bernard J. [Gravitational Astrophysics Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771 (United States); Boggs, William D.; McWilliams, Sean T. [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States)

    2008-02-15

    We present a multipolar analysis of the gravitational recoil computed in recent numerical simulations of binary black hole coalescence, for both unequal masses and nonzero, nonprecessing spins. We show that multipole moments up to and including l=4 are sufficient to accurately reproduce the final recoil velocity (within {approx_equal}2%) and that only a few dominant modes contribute significantly to it (within {approx_equal}5%). We describe how the relative amplitudes, and more importantly, the relative phases, of these few modes control the way in which the recoil builds up throughout the inspiral, merger, and ringdown phases. We also find that the numerical results can be reproduced by an 'effective Newtonian' formula for the multipole moments obtained by replacing the radial separation in the Newtonian formulas with an effective radius computed from the numerical data. Beyond the merger, the numerical results are reproduced by a superposition of three Kerr quasinormal modes. Analytic formulas, obtained by expressing the multipole moments in terms of the fundamental quasinormal modes of a Kerr black hole, are able to explain the onset and amount of 'antikick' for each of the simulations. Lastly, we apply this multipolar analysis to help explain the remarkable difference between the amplitudes of planar and nonplanar kicks for equal-mass spinning black holes.

  12. Recoil-induced Resonances as All-optical Switches

    NASA Astrophysics Data System (ADS)

    Narducci, F. A.; Desavage, S. A.; Gordon, K. H.; Duncan, D. L.; Welch, G. R.; Davis, J. P.

    2010-03-01

    We have measured recoil-induced resonances (RIR) [1,2] in our system of laser-cooled 85Rb atoms. Although this technique has been demonstrated to be useful for the purpose of extracting the cloud temperature [3], our aim was to demonstrate an all optical switch based on recoil-induced resonances. In addition to a very narrow ``free-space'' recoil-induced resonance of approximately 15 kHz, we also discovered a much broader resonance (˜30 MHz), caused by standing waves established by our trapping fields. We compare and contrast the switching dynamics of these two resonances and demonstrate optical switching using both resonances. Finally, we consider the applicability of the narrow, free-space resonance to the slowing of a weak probe field. [1] J. Guo, P.R. Berman, B. Dubetsky and G. Grynberg PRA, 46, 1426 (1992). [2] (a) P. Verkerk, B. Loumis, C. Salomon, C. Cohen-Tannoudji, J. Courtois PRL, 68, 3861 (1992). (b) G. Grynberg, J-Y Courtois, B. Lounis, P. Verkerk PRL, 72, 3017 (1994). [3] (a) T. Brzozowski, M. Brzozowska, J. Zachorowski, M. Zawada, W. Gawlik PRA, 71, 013401 (2005). (b) M. Brzozowska, T. Brzozowski J. Zachorowski, W. Gawlik PRA, 72, 061401(R), (2005).

  13. Anatomy of the Binary Black Hole Recoil: A Multipolar Analysis

    NASA Technical Reports Server (NTRS)

    Schnittman, Jeremy; Buonanno, Alessandra; vanMeter, James R.; Baker, John G.; Boggs, William D.; Centrella, Joan; Kelly, Bernard J.; McWilliams, Sean T.

    2007-01-01

    We present a multipolar analysis of the recoil velocity computed in recent numerical simulations of binary black hole coalescence, for both unequal masses and non-zero, non-precessing spins. We show that multipole moments up to and including 1 = 4 are sufficient to accurately reproduce the final recoil velocity (= 98%) and that only a few dominant modes contribute significantly to it (2 95%). We describe how the relative amplitude, and more importantly, the relative phase, of these few modes control the way in which the recoil builds up throughout the inspiral, merger, and ring-down phases. We also find that the numerical results can be reproduced, to a high level of accuracy, by an effective Newtonian formula for the multipole moments obtained by replacing in the Newtonian formula the radial separation with an effective radius computed from the numerical data. Beyond the merger, the numerical results are reproduced by a superposition of three Kerr quasi-normal modes. Analytic formulae, obtained by expressing the multipole moments in terms of the fundamental QNMs of a Kerr BH, are able to explain the onset and amount of '.anti-kick" for each of the simulations. Lastly, we apply this multipolar analysis to understand the remarkable difference between the amplitudes of planar and non-planar kicks for equal-mass spinning black holes.

  14. Recoiling black holes: electromagnetic signatures, candidates, and astrophysical implications

    E-print Network

    S. Komossa

    2012-02-09

    Supermassive black holes (SMBHs) may not always reside right at the centers of their host galaxies. This is a prediction of numerical relativity simulations, which imply that the newly formed single SMBH, after binary coalescence in a galaxy merger, can receive kick velocities up to several 1000 km/s due to anisotropic emission of gravitational waves. Long-lived oscillations of the SMBHs in galaxy cores, and in rare cases even SMBH ejections from their host galaxies, are the consequence. Observationally, accreting recoiling SMBHs would appear as quasars spatially and/or kinematically off-set from their host galaxies. The presence of the "kicks" has a wide range of astrophysical implications which only now are beginning to be explored, including consequences for black hole and galaxy assembly at the epoch of structure formation, black hole feeding, and unified models of Active Galactic Nuclei (AGN). Here, we review the observational signatures of recoiling SMBHs and the properties of the first candidates which have emerged, including follow-up studies of the candidate recoiling SMBH of SDSSJ092712.65+294344.0.

  15. ALPHA OMEGA ALPHA National Honor Medical Society

    E-print Network

    12/6/2012 1 ALPHA OMEGA ALPHA National Honor Medical Society www.alphaomegaalpha.org AA and Leadership The Alpha Omega Alpha honor medical society was organized in 1902 to "recognize and perpetuate Omega Alpha Honor Medical Society Wisconsin beta Chapter All upcoming MCW seniors who are interested

  16. H Ly-alpha transmittance of thin foils of C, Si/C, and Al/C for keV particle detectors

    NASA Technical Reports Server (NTRS)

    Drake, V. A.; Sandel, B. R.; Jenkins, D. G.; Hsieh, K. C.

    1992-01-01

    A class of instruments designed for remote sensing of space plasmas by measuring energetic neutral atoms (ENA) uses a thin foil as both a signal generator and a light shield. An ENA imager must look directly at the ENA source region, which is also usually an intense source of H Ly-alpha (1216 A) photons. It is desirable to minimize the energy threshold for ENA detectors, at the same time maximizing the blocking of H Ly-alpha. Optimizing filter design to meet these two contrary requirements has led us to measure the transmittance of thin C, Si/C, and Al/C foils at H Ly-alpha. Our results indicate that (1) transmittance of less than 0.0007 can be achieved with 7 micro-g/sq cm Si on 1.7 micro-g/sq cm C; (2) an Si/C composite foil with a thin carbon layer is more effective in blocking UV radiation while having the lowest energy threshold of all the foils measured; and (3) transmittance of Si/C foils of known Si and C thicknesses cannot be accurately predicted, but must be measured.

  17. Measurement of the track etch rates along proton and alpha particle trajectories in CR39 and calculation of the detection efficiency

    Microsoft Academic Search

    B. Dörschel; R. Bretschneider; D. Hermsdorf; K. Kadner; H. Kühne

    1999-01-01

    Computation of the neutron response of CR-39 detectors needs to simulate the track formation by neutron induced charged particles taking into account the bulk etch rate and the track etch rate varying along the particle trajectories. The latter one was determined experimentally by track length measurement. The results allowed to derive the relationship between the track etch rate and the

  18. Alpha-1 Antitrypsin Deficiency

    MedlinePLUS

    ... Liver Disease Information > Alpha-1 Antitrypsin Deficiency Alpha-1 Antitrypsin Deficiency Explore this section to learn more about alpha-1 antitrypsin deficiency, including a description of the disorder ...

  19. Synthesis of single phase {alpha}-Fe, Fe{sub 3}C and Fe{sub 7}C{sub 3} nano-particles by CO{sub 2} laser pyrolysis technique. Quarterly progress report, January--March, 1992

    SciTech Connect

    Eklund, P.C.; Bi, X.X.

    1992-07-01

    Iron-containing catalysts have been known to be useful in assisting the Fischer-Tropsch (FT) reaction for synthesizing hydrocarbons. However, it has been well recognized that iron catalyst are not stable during the reaction but converted into iron carbides. It is thus important to understand the role of the iron carbides in the catalytic reaction of the FT-synthesis. It has been found difficult to produce iron carbide nano-particles as a single phase, because iron carbide phases are only metastable under 1 atm pressure. Iron carbide bulk particles prepared so far are often contaminated with metallic iron, iron oxides and free carbon. In this study, we investigate the synthesis of iron carbide nano-particles using CO{sub 2} laser pyrolysis technique. We show that this technique is successful in synthesizing {alpha}-Fe, Fe{sub 3}C and Fe{sub 7}C{sub 3} nano-particles in their single phase with sizes in the range of 5--20nm. In particular, we have produced for the first time the Fe{sub 7}C{sub 3} which has been known to exist but unable to be produced as a single phase. Furthermore, it is interesting that Fe{sub 5}C{sub 2} which has carbon and iron ratio between Fe{sub 3}C and Fe{sub 7}C{sub 3}, is not seen in any run of our synthesis.

  20. g-Factor Measurements of First 2+ States of Heavy Te Isotopes Based on Nuclear Spin Deorientation for Nuclei Recoiling in Vacuum

    SciTech Connect

    Danchev, M. [University of Tennessee, Knoxville (UTK); Pavan, John R [ORNL; Stone, Nicholas J [ORNL; Stuchberry, A. E. [Australian National University, Canberra, Australia; Baktash, Cyrus [ORNL; Beene, James R [ORNL; Benczer-Koller, N. [Rutgers University; Bingham, Carrol R [ORNL; Dupak, J. [Institute of Scientific Instruments, Czech Republic; Galindo-Uribarri, Alfredo {nmn} [ORNL; Gross, Carl J [ORNL; Kumbartzki, Gerfried J [ORNL; Radford, David C [ORNL; Stone, Jirina R [ORNL; Timlin, Claire L [ORNL; Yu, Chang-Hong [ORNL; Zamfir, Nicolae Victor [ORNL

    2005-12-01

    We demonstrate that the recoil-in-vacuum (RIV) method can be used to determine the g-factor of the Coulomb excited first 2+ state of {sup 132}Te. This was possible owing to advantages provided by CLARION (ORNL clover multi-detector array) and the segmented charged particle detector HyBall. Calibratory experiments were performed with {sup 122,126,130}Te and a g-factor of {sup 132}Te was deduced g = (+)0.35(5).