Science.gov

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. Alpha Particle

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    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...

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. Imaging alpha particle detector

    DOEpatents

    Anderson, David F. (Los Alamos, NM)

    1985-01-01

    A method and apparatus for detecting and imaging alpha particles sources is described. A conducting coated high voltage electrode (1) and a tungsten wire grid (2) 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 (3) to be quantitatively or qualitatively analyzed. A thin polyester film window (4) 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. Alpha-particle diagnostics

    SciTech Connect

    Young, K.M.

    1991-01-01

    This paper will focus on the state of development of diagnostics which are expected to provide the information needed for {alpha}- physics studies in the future. Conventional measurement of detailed temporal and spatial profiles of background plasma properties in DT will be essential for such aspects as determining heating effectiveness, shaping of the plasma profiles and effects of MHD, but will not be addressed here. This paper will address (1) the measurement of the neutron source, and hence {alpha}-particle birth profile, (2) measurement of the escaping {alpha}-particles and (3) measurement of the confined {alpha}-particles over their full energy range. There will also be a brief discussion of (4) the concerns about instabilities being generated by {alpha}-particles and the methods necessary for measuring these effects. 51 refs., 10 figs.

  11. Alpha Particle Diagnostic

    SciTech Connect

    Fisher, Ray, K.

    2009-05-13

    The study of burning plasmas is the next frontier in fusion energy research, and will be a major objective of the U.S. fusion program through U.S. collaboration with our international partners on the ITER Project. For DT magnetic fusion to be useful for energy production, it is essential that the energetic alpha particles produced by the fusion reactions be confined long enough to deposit a significant fraction of their initial ~3.5 MeV energy in the plasma before they are lost. Development of diagnostics to study the behavior of energetic confined alpha particles is a very important if not essential part of burning plasma research. Despite the clear need for these measurements, development of diagnostics to study confined the fast confined alphas to date has proven extremely difficult, and the available techniques remain for the most part unproven and with significant uncertainties. Research under this grant had the goal of developing diagnostics of fast confined alphas, primarily based on measurements of the neutron and ion tails resulting from alpha particle knock-on collisions with the plasma deuterium and tritium fuel ions. One of the strengths of this approach is the ability to measure the alphas in the hot plasma core where the interesting ignition physics will occur.

  12. 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.

  13. Long range alpha particle detector

    DOEpatents

    MacArthur, D.W.; Wolf, M.A.; McAtee, J.L.; Unruh, W.P.; Cucchiara, A.L.; Huchton, R.L.

    1993-02-02

    An alpha particle detector capable of detecting alpha radiation from distant sources. In one embodiment, a high voltage is generated in a first electrically conductive mesh while a fan draws air containing air molecules ionized by alpha particles through an air passage and across a second electrically conductive mesh. The current in the second electrically conductive mesh can be detected and used for measurement or alarm. The detector can be used for area, personnel and equipment monitoring.

  14. Long range alpha particle detector

    DOEpatents

    MacArthur, Duncan W. (Los Alamos, NM); Wolf, Michael A. (Los Alamos, NM); McAtee, James L. (Los Alamos, NM); Unruh, Wesley P. (Los Alamos, NM); Cucchiara, Alfred L. (Los Alamos, NM); Huchton, Roger L. (Los Alamos, NM)

    1993-01-01

    An alpha particle detector capable of detecting alpha radiation from distant sources. In one embodiment, a high voltage is generated in a first electrically conductive mesh while a fan draws air containing air molecules ionized by alpha particles through an air passage and across a second electrically conductive mesh. The current in the second electrically conductive mesh can be detected and used for measurement or alarm. The detector can be used for area, personnel and equipment monitoring.

  15. Nuclear Alpha-Particle Condensates

    E-print Network

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

    2011-03-21

    The $\\alpha$-particle condensate in nuclei is a novel state described by a product state of $\\alpha$'s, all with their c.o.m. in the lowest 0S orbit. We demonstrate that a typical $\\alpha$-particle condensate is the Hoyle state ($E_{x}=7.65$ MeV, $0^+_2$ state in $^{12}$C), which plays a crucial role for the synthesis of $^{12}$C in the universe. The influence of antisymmentrization in the Hoyle state on the bosonic character of the $\\alpha$ particle is discussed in detail. It is shown to be weak. The bosonic aspects in the Hoyle state, therefore, are predominant. It is conjectured that $\\alpha$-particle condensate states also exist in heavier $n\\alpha$ nuclei, like $^{16}$O, $^{20}$Ne, etc. For instance the $0^+_6$ state of $^{16}$O at $E_{x}=15.1$ MeV is identified from a theoretical analysis as being a strong candidate of a $4\\alpha$ condensate. The calculated small width (34 keV) of $0^+_6$, consistent with data, lends credit to the existence of heavier Hoyle-analogue states. In non-self-conjugated nuclei such as $^{11}$B and $^{13}$C, we discuss candidates for the product states of clusters, composed of $\\alpha$'s, triton's, and neutrons etc. The relationship of $\\alpha$-particle condensation in finite nuclei to quartetting in symmetric nuclear matter is investigated with the help of an in-medium modified four-nucleon equation. A nonlinear order parameter equation for quartet condensation is derived and solved for $\\alpha$ particle condensation in infinite nuclear matter. The strong qualitative difference with the pairing case is pointed out.

  16. Alpha particle emitters in medicine

    SciTech Connect

    Fisher, D.R.

    1989-09-01

    Radiation-induced cancer of bone, liver and lung has been a prominent harmful side-effect of medical applications of alpha emitters. In recent years, however, the potential use of antibodies labeled with alpha emitting radionuclides against cancer has seemed promising because alpha particles are highly effective in cell killing. High dose rates at high LET, effectiveness under hypoxic conditions, and minimal expectancy of repair are additional advantages of alpha emitters over antibodies labeled with beta emitting radionuclides for cancer therapy. Cyclotron-produced astatine-211 ({sup 211}At) and natural bismuth-212 ({sup 212}Bi) have been proposed and are under extensive study in the United States and Europe. Radium-223 ({sup 223}Ra) also has favorable properties as a potential alpha emitting label, including a short-lived daughter chain with four alpha emissions. The radiation dosimetry of internal alpha emitters is complex due to nonuniformly distributed sources, short particle tracks, and high relative specific ionization. The variations in dose at the cellular level may be extreme. Alpha-particle radiation dosimetry, therefore, must involve analysis of statistical energy deposition probabilities for cellular level targets. It must also account fully for nonuniform distributions of sources in tissues, source-target geometries, and particle-track physics. 18 refs., 4 figs.

  17. Alpha particle confinement in tokamaks

    SciTech Connect

    White, R.B.; Mynick, H.E.

    1988-11-01

    An assessment of diffusive tokamak transport mechanisms of concern for alpha particles indicates that the ''stochastic regime'' is the only one which appears to pose a real danger for adequate alpha confinement. This fact, in conjunction with the threshold character of that mechanism, allows one to decide whether an alpha born at a given location will be lost or confined, according to a very simple criterion. Implementing this criterion numerically results in a new code for the assessment of alpha confinement, which is orders of magnitude faster than earlier codes used for this purpose. 13 refs., 3 figs., 1 tab.

  18. 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.

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

    E-print Network

    .1016/S0168-583X(03)00676-1 Nuclear Instruments and Methods in Physics Research B 209 (2003) 351­356 www, E-11510 Puerto Real, Spain Abstract Alpha-recoil tracks (ART) are lattice defects caused by the a-decay of 238 U, 235 U, 232 Th, and daughter products. Visualization of etched ARTs in dark mica by phase

  20. 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.

  1. Alpha particles in effective field theory

    SciTech Connect

    Caniu, C.

    2014-11-11

    Using an effective field theory for alpha (?) particles at non-relativistic energies, we calculate the strong scattering amplitude modified by Coulomb corrections for a system of two ?s. For the strong interaction, we consider a momentum-dependent interaction which, in contrast to an energy dependent interaction alone [1], could be more useful in extending the theory to systems with more than two ? particles. We will present preliminary results of our EFT calculations for systems with two alpha particles.

  2. Alpha particles in effective field theory

    NASA Astrophysics Data System (ADS)

    Caniu, C.

    2014-11-01

    Using an effective field theory for alpha (?) particles at non-relativistic energies, we calculate the strong scattering amplitude modified by Coulomb corrections for a system of two ?s. For the strong interaction, we consider a momentum-dependent interaction which, in contrast to an energy dependent interaction alone [1], could be more useful in extending the theory to systems with more than two ? particles. We will present preliminary results of our EFT calculations for systems with two alpha particles.

  3. Concepts of alpha-particle condensation

    E-print Network

    Y. Funaki; H. Horiuchi; W. von Oertzen; G. Roepke; P. Schuck; A. Tohsaki; T. Yamada

    2009-12-15

    Certain aspects of the recently proposed antisymmetrised alpha particle product state wave function, or THSR alpha cluster wave function, for the description of the ground state in 8Be, the Hoyle state in 12C, and analogous states in heavier nuclei, are elaborated in detail. For instance, the influence of antisymmetrisation in the Hoyle state on the bosonic character of the alpha particles is studied carefully. It is shown to be weak, so that bosonic aspects are predominant. The de Broglie wave length of alpha particles in the Hoyle state is shown to be much larger than the inter-alpha distance. It is pointed out that the bosonic features of low density alpha gas states have measurable consequences, one of which, that is enhanced multi-alpha decay properties, likely already have been detected. Consistent with experiment, the width of the proposed analogue to the Hoyle state in 16O at the excitation energy of E_x=15.1 MeV is estimated to be very small (34 keV), lending credit to the existence of heavier Hoyle-like states. The intrinsic single boson density matrix of a self-bound Bose system can, under physically desirable boundary conditions, be defined unambiguously. One eigenvalue then separates out, being close to the number of alpha's in the system. Differences between Brink and THSR alpha cluster wave functions are worked out. No cluster model of the Brink type can describe the Hoyle state with a single configuration. On the contrary, many superpositions of the Brink type are necessary, implying delocalisation towards an alpha product state. It is shown that single alpha particle orbits in condensates of different nuclei are almost the same. It is thus argued that alpha particle antisymmetrised product states of the THSR type are a very promising novel and useful concept in nuclear physics.

  4. 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

  5. Dynamics of Primordial Hydrogen Recombination with Allowance for a Recoil for Scattering in the Ly-alpha Line

    E-print Network

    S. I. Grachev; V. K. Dubrovich

    2008-01-22

    It is shown that taking into account a recoil for radiation scattering in the Ly-alpha line can lead to a noticable acceleration of primordial hydrogen recombination. Thus for LambdaCDM model a decrease of ionization degree exceeds 1% for redshifts z in a range 800 - 1050 achieving approximately 1.3% at z=900. Corresponding corrections to the cosmic microwave background power spectra can achieve 1.1% for TT spectra and 1.7% for EE ones. Radiative transfer in these calculations was treated in a quasistationary approximation. Numerical solutions are also obtained in diffusion approximation for a nonstationary problem of Ly-alpha line radiative transfer under partial frequency redistribution with a recoil. An evolution of a local line profile is traced to as well as an evolution of a relative number of uncompensated transitions from 2p state down to 1s one. It is shown that taking into account nonstationarity of Ly-alpha line radiative transfer can lead to an additional acceleration of primordial hydrogen recombination.

  6. Nuclear diagnostic for fast alpha particles

    DOEpatents

    Grisham, L.R.; Post, D.E. Jr.; Dawson, J.M.

    1983-11-23

    This invention relates generally to high energy confined plasmas and more particularly is directed to measuring the velocity distribution of confined energetic alpha particles resulting from deuterium-tritium fusion reactions in a confined energetic plasma.

  7. A new setup for elastic recoil analysis using ion induced electron emission for particle identification

    NASA Astrophysics Data System (ADS)

    Steinbauer, E.; Benka, O.; Steinbatz, M.

    1998-03-01

    We describe a new setup for elastic recoil detection analysis (ERDA) using our recently developed particle identification method. Before the ions and elastic recoil atoms from the target reach a silicon surface barrier detector for energy analysis, they penetrate a set of thin foils (e.g. carbon). The ion induced electron emission yield from the foils depends on the nuclear charge of the penetrating ion and it is roughly proportional to the energy loss in the foil. The emitted electrons are accelerated towards a microchannel plate (MCP), which gives a signal amplitude proportional to the number of emitted electrons. This signal is measured in coincidence with the energy signal from the surface barrier detector using our dual-parameter multichannel analyzer system M2D. Since the energy resolution is not measurably deteriorated by the particle identification our setup offers optimum depth resolution for light elements. Due to the compact design large solid angles for high sensitivity can be achieved. A new measuring chamber has been built which offers considerable improvements. The ERDA scattering angle (30° or 45°) and the target orientation can be selected for optimum depth resolution or sensitivity. Element separation for light elements has been enhanced by several improvements: A new geometry of the foil setup improves the collection efficiency for ion induced electrons onto the MCP, coating of the carbon foils with insulators enhances the electron emission yield. Finally, a new data evaluation procedure has been developed in which the pulse height spectrum of the MCP is considered to be a linear combination of individual spectra from the incident ion and of the recoil atoms. The normalized shapes of these spectra are taken from calibration measurements, the intensities are then calculated using a linear fitting algorithm and finally give the depth profiles of the elements in the target. For hydrogen in near surface layers even isotopic separation is possible. Examples for 1H and 2H in a Be matrix will be given.

  8. Typical uncertainties in alpha-particle spectrometry

    NASA Astrophysics Data System (ADS)

    Pommé, S.

    2015-06-01

    Alpha-particle spectrometry is routinely performed with the aim of measuring absolute activities, activity ratios between different alpha-emitting nuclides or decay data such as branching factors, alpha emission probabilities and relative half-lives. It is most commonly performed with ion-implanted silicon detectors. Strong features of the technique are the low background levels that can be achieved due to low sensitivity to other types of radiation, the intrinsic efficiency close to 1 which reduces the efficiency calculations to a geometrical problem and the uniqueness of the energy spectra for each ?-decaying nuclide. The main challenge is the limitation to the attainable energy resolution, even with thin and homogenous sources, which causes alpha energy peaks to be partially unresolved due to their width and low-energy tailing. The spectral deconvolution often requires fitting of analytical functions to each peak in the alpha spectrum. True coincidence effects between alpha particles and subsequently emitted conversion electrons cause distortions of the alpha spectra which lead to significant changes in the apparent peak area ratios. Optimum energy resolution can only be achieved on very thin sources, which puts constraints on the source preparation techniques. Radiochemical separations may be needed to extract the alpha emitters from voluminous matrices and efficiency tracing is performed by adding in another isotope by known amounts. Typical uncertainty components are discussed by means of some hypothetical examples.

  9. Alpha-particle sensitive test SRAMs

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Blaes, B. R.

    1990-01-01

    A bench-level test is being developed to evaluate memory-cell upsets in a test SRAM designed with a cell offset voltage. This offset voltage controls the critical charge needed to upset the cell. The effect is demonstrated using a specially designed 2-micron n-well CMOS 4-kb test SRAM and a Po-208 5.1-MeV 0.61-LET alpha-particle source. This test SRAM has been made sensitive to alpha particles through the use of a cell offset voltage, and this has allowed a bench-level characterization in a laboratory setting. The experimental data are linked to a alpha-particle interaction physics and to SPICE circuit simulations through the alpha-particle collection depth. The collection depth is determined by two methods and found to be about 7 micron. In addition, alpha particles that struck outside the bloated drain were able to flip the SRAM cells. This lateral charge collection was observed to be more than 6 micron.

  10. Measurement of $\\alpha$-particle quenching in LAB based scintillator in independent small-scale experiments

    E-print Network

    von Krosigk, B; Hans, S; Junghans, A R; Kögler, T; Kraus, C; Kuckert, L; Liu, X; Nolte, R; O'Keeffe, H M; Tseung, H S Wan Chan; Wilson, J R; Wright, A; Yeh, M; Zuber, K

    2015-01-01

    The $\\alpha$-particle light response of liquid scintillators based on linear alkylbenzene (LAB) has been measured with three different experimental approaches. In the first approach, $\\alpha$-particles were produced in the scintillator via $^{12}$C($n$,$\\alpha$)$^9$Be reactions. In the second approach, the scintillator was loaded with 2% of $^{\\mathrm{nat}}$Sm providing an $\\alpha$-emitter, $^{147}$Sm, as an internal source. In the third approach, a scintillator flask was deployed into the water-filled SNO+ detector and the radioactive contaminants $^{222}$Rn, $^{218}$Po and $^{214}$Po provided the $\\alpha$-particle signal. The behavior of the observed $\\alpha$-particle light outputs are in agreement with each case successfully described by Birks' law. The resulting Birks parameter $kB$ ranges from $(0.0071\\pm0.0003)$ cm/MeV to $(0.0076\\pm0.0003)$ cm/MeV. In the first approach, the $\\alpha$-particle light response was measured simultaneously with the light response of recoil protons produced via neutron-proto...

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Lunar surface outgassing and alpha particle measurements

    SciTech Connect

    Lawson, S. L.; Feldman, W. C.; Lawrence, David J. ,; Moore, K. R.; Elphic, R. C.; Maurice, S.; Belian, Richard D.; Binder, Alan B.

    2002-01-01

    The Lunar Prospector Alpha Particle Spectrometer (LP APS) searched for lunar surface gas release events and mapped their distribution by detecting alpha particle?; produced by the decay of gaseous radon-222 (5.5 MeV, 3.8 day half-life), solid polonium-2 18 (6.0 MeV, 3 minute half-life), and solid polonium-210 (5.3 MeV, 138 day half-life, but held up in production by the 21 year half-life of lead-210). These three nuclides are radioactive daughters from the decay of uranium-238.

  16. Nuclear Alpha-Particle Condensates

    NASA Astrophysics Data System (ADS)

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

    The ?-particle condensate in nuclei is a novel state described by a product state of ?'s, all with their c.o.m. in the lowest 0S orbit. We demonstrate that a typical ?-particle condensate is the Hoyle state (Ex=7.65 MeV,0^+_2 state in ^{12}C), which plays a crucial role for the synthesis of ^{12}C in the universe. The influence of antisymmentrization in the Hoyle state on the bosonic character of the ? particle is discussed in detail. It is shown to be weak. The bosonic aspects in the Hoyle state, therefore, are predominant. It is conjectured that ?-particle condensate states also exist in heavier n? nuclei, like ^{16}O,^{20}Ne, etc. For instance the 0^+_6 state of ^{16}O at Ex=15.1 MeV is identified from a theoretical analysis as being a strong candidate of a 4? condensate. The calculated small width (140 keV) of 0^+_6, consistent with data, lends credit to the existence of heavier Hoyle-analogue states. In non-self-conjugated nuclei such as ^{11} B and ^{13} C, we discuss candidates for the product states of clusters, composed of ?'s, triton's, and neutrons etc. The relationship of ?-particle condensation in finite nuclei to quartetting in symmetric nuclear matter is investigated with the help of an in-medium modified four-nucleon equation. A nonlinear order parameter equation for quartet condensation is derived and solved for ? particle condensation in infinite nuclear matter. The strong qualitative difference with the pairing case is pointed out.

  17. 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.

  18. 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.

  19. Alpha Particle Physics Experiments in the Tokamak Fusion Test Reactor

    SciTech Connect

    Budny, R.V.; Darrow, D.S.; Medley, S.S.; Nazikian, R.; Zweben, S.J.; et al.

    1998-12-14

    Alpha particle physics experiments were done on the Tokamak Fusion Test Reactor (TFTR) during its deuterium-tritium (DT) run from 1993-1997. 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 magnetohydrodynamic (MHD) quiescent discharges. Also, the observed alpha particle interactions with sawteeth, toroidal Alfvén eigenmodes (TAE), and ion cyclotron resonant frequency (ICRF) waves were roughly consistent with theoretical modeling. This paper reviews what was learned and identifies what remains to be understood.

  20. Thermal recrystallization of alpha-recoil damaged minerals of the pyrochlore structure type

    SciTech Connect

    Lumpkin, G.R.; Ewing, R.C.; Foltyn, E.M.

    1985-10-01

    Thermal recrystallization effects (heat of recrystallization and identification of phases formed), have been determined for naturally occurring members of the pyrochlore group which have received alpha doses of up to 4 X 10{sup 16} alphas/mg. The heats of recrystallization, E{sub t}, range from 125 to 210 J/g. Release of energy decreases as a function of crystallinity (estimated on the basis of the intensity of x-ray diffraction maxima), with the fully-metamict samples approaching 210 J/g. Lower measured values (40-125 J/g) are the result of alteration of the pyrochlores. Other metamict, complex oxides with stoichiometries of ABO{sub 4} and AB{sub 2}O{sub 6} have lower heats of recrystallization (40-85 J/g), and are easily distinguished from pyrochlore group minerals. Activation energies of recrystallization, E{sub a}, range between values of 0.29 to 0.97 eV, less than those measured for Pu-doped, synthetic zirconolites.

  1. Recoil-Implantation Of Multiple Radioisotopes Towards Wear Rate Measurements And Particle Tracing In Prosthetic Joints

    NASA Astrophysics Data System (ADS)

    Warner, Jacob A.; Smith, Paul N.; Scarvell, Jennifer M.; Gladkis, Laura; Timmers, Heiko

    2011-06-01

    This study demonstrates a new method of radioisotope labeling of ultra-high molecular weight polyethylene inserts in prosthetic joints for wear studies. The radioisotopes 97Ru, 100Pd, 100Rh, and 101mRh are produced in fusion evaporation reactions induced by 12C ions in a 92Zr target foil. The fusion products recoil-implant into ultra-high molecular weight polyethylene plugs, machined to fit into the surface of the inserts. During laboratory simulations of the joint motion, a wear rate of the labeled polyethylene may be measured and the pathways of wear debris particles can be traced by detecting characteristic gamma-rays. The concentration profiles of the radioisotopes extend effectively uniformly from the polyethylene surface to a depth of about 4 ?m. The multiplicity of labeling and the use of several gamma-ray lines aids with avoiding systematic measurement uncertainties. Two polyethylene plugs were labeled and one was fitted into the surface of the tibial insert of a knee prosthesis, which had been worn in. Actuation over close to 100,000 cycles with a 900 N axial load and a 24° flexion angle removed (14±1)% of the gamma-ray activity from the plug. Most of this activity dispersed into the serum lubricant identifying this as the important debris pathway. Less than 1% activity was transferred to the femoral component of the prosthesis and the measured activity on the tibial tray was insignificant. Assuming uniform wear across the superior surface of the insert, a wear rate of (12±3) mm3/Megacycle was determined. This is consistent with wear rate measurements under similar conditions using other techniques.

  2. Recoil-Implantation Of Multiple Radioisotopes Towards Wear Rate Measurements And Particle Tracing In Prosthetic Joints

    SciTech Connect

    Warner, Jacob A.; Timmers, Heiko; Smith, Paul N.; Scarvell, Jennifer M.; Gladkis, Laura

    2011-06-01

    This study demonstrates a new method of radioisotope labeling of ultra-high molecular weight polyethylene inserts in prosthetic joints for wear studies. The radioisotopes {sup 97}Ru, {sup 100}Pd, {sup 100}Rh, and {sup 101m}Rh are produced in fusion evaporation reactions induced by {sup 12}C ions in a {sup 92}Zr target foil. The fusion products recoil-implant into ultra-high molecular weight polyethylene plugs, machined to fit into the surface of the inserts. During laboratory simulations of the joint motion, a wear rate of the labeled polyethylene may be measured and the pathways of wear debris particles can be traced by detecting characteristic gamma-rays. The concentration profiles of the radioisotopes extend effectively uniformly from the polyethylene surface to a depth of about 4 {mu}m. The multiplicity of labeling and the use of several gamma-ray lines aids with avoiding systematic measurement uncertainties. Two polyethylene plugs were labeled and one was fitted into the surface of the tibial insert of a knee prosthesis, which had been worn in. Actuation over close to 100,000 cycles with a 900 N axial load and a 24 deg. flexion angle removed (14{+-}1)% of the gamma-ray activity from the plug. Most of this activity dispersed into the serum lubricant identifying this as the important debris pathway. Less than 1% activity was transferred to the femoral component of the prosthesis and the measured activity on the tibial tray was insignificant. Assuming uniform wear across the superior surface of the insert, a wear rate of (12{+-}3) mm{sup 3}/Megacycle was determined. This is consistent with wear rate measurements under similar conditions using other techniques.

  3. {alpha}-particle optical potential tests below the Coulomb barrier

    SciTech Connect

    Avrigeanu, M.; Avrigeanu, V.

    2009-02-15

    The results of two recent papers concerning ({alpha},{gamma}) and ({alpha},n) reaction cross sections close to the reaction thresholds are discussed with regard to predictions of a recent {alpha}-particle regional optical potential. It is found that the new measured cross sections are rather well described especially for the dominant reaction channels. Particular features of the {alpha}-particle optical potential at energies below the Coulomb barrier explain the failure of a former regional potential obtained by analysis of {alpha}-particle elastic scattering alone at higher energies. Additional limitations of statistical model calculations for minor reaction channels are also discussed.

  4. Turbulent transport of alpha particles in reactor plasmas

    SciTech Connect

    Estrada-Mila, C.; Candy, J.; Waltz, R. E.

    2006-11-15

    A systematic study of the behavior of energetic ions in reactor plasmas is presented. Using self-consistent gyrokinetic simulations, in concert with an analytic asymptotic theory, it is found that alpha particles can interact significantly with core ion-temperature-gradient turbulence. Specifically, the per-particle flux of energetic alphas is comparable to the per-particle flux of thermal species (deuterium or helium ash). This finding opposes the conventional wisdom that energetic ions, because of their large gyroradii, do not interact with the turbulence. For the parameters studied, a turbulent modification of the alpha-particle density profile appears to be stronger than turbulent modification of the alpha-particle pressure profile. Crude estimates indicate that the alpha density modification, which is directly proportional to the core turbulence intensity, could be in the range of 15% at midradius in a reactor. The corresponding modification of the alpha-particle pressure profile is predicted to be smaller (in the 1% range)

  5. Alpha-Particle Gas-Pressure Sensor

    NASA Technical Reports Server (NTRS)

    Buehler, M. C.; Bell, L. D.; Hecht, M. H.

    1996-01-01

    An approximate model was developed to establish design curves for the saturation region and a more complete model developed to characterize the current-voltage curves for an alpha-particle pressure sensor. A simple two-parameter current-voltage expression was developed to describe the dependence of the ion current on pressure. The parameters are the saturation-current pressure coefficient and mu/D, the ion mobility/diffusion coefficient. The sensor is useful in the pressure range between 0.1 and 1000 mb using a 1 - mu Ci(241) Am source. Experimental results, taken between 1 and up to 200 mb, show the sensor operates with an anode voltage of 5 V and a sensitivity of 20 fA/mb in nitrogen.

  6. 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.

  7. Collective alpha-particle effects in burning plasma experiments.

    E-print Network

    ¦ ¥¦¡ G ¦ ¢ ¢ £ ¨¦ ¤ £ ¥ ¨¦ G ¦ ¥ ¡ ¥ Q S £ © £ ¦ £ ¥ ! #12;Collective alpha-particle effects can be grouped into: 1. single particle 2. collective Have to answer: Will alphas be confined in BP activity (PD, BP) 2. collective: Fish-bone instability (PD, BP) Alfvén instabilities (TAE

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

    E-print Network

    Yu, Peter K.N.

    ALPHA-PARTICLE RADIOBIOLOGICAL EXPERIMENTS USING THIN CR-39 DETECTORS K. F. Chan1 , S. Y. M. Siu2 of the human respiratory tract. It is therefore pertinent to estimate the risk by investigating the biological. These can be studied in alpha-particle radiobiological experiments to determine the rela- tionship between

  9. 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.

  10. A High-Throughput Screen for Alpha Particle Radiation Protectants

    PubMed Central

    Seideman, Jonathan H.; Shum, David; Djaballah, Hakim

    2010-01-01

    Abstract Alpha-particle-emitting elements are of increasing importance as environmental and occupational carcinogens, toxic components of radiation dispersal devices and accidents, and potent therapeutics in oncology. Alpha particle radiation differs from radiations of lower linear energy transfer in that it predominantly damages DNA via direct action. Because of this, radical scavengers effective for other radiations have had only limited effect in mitigating alpha particle toxicity. We describe here a simple assay and a pilot screen of 3,119 compounds in a high-throughput screen (HTS), using the alpha-particle-emitting isotope, 225Ac, for the discovery of compounds that might protect mammalian cells from alpha particles through novel mechanisms. The assay, which monitored the viability of a myeloid leukemic cell line upon alpha particle exposure, was robust and reproducible, yielding a Z' factor of 0.66 and a signal-to-noise ratio of nearly 10 to 1. Surprisingly, 1 compound emerged from this screen, epoxy-4,5-?-dihydroxysantonin (EDHS), that showed considerable protective activity. While the value of EDHS remains to be determined, its discovery is a proof of concept and validation of the utility of this HTS methodology. Further application of the described assay could yield compounds useful in minimizing the toxicity and carcinogenesis associated with alpha particle exposure. PMID:20658946

  11. The mutagenicity of. cap alpha. particles from plutonium-238

    SciTech Connect

    Thacker, J.; Stretch, A.; Goodhead, D.T.

    1982-11-01

    Cell killing and the frequency of mutation to thioguanine resistance (HGPRT enzyme deficiency) were measured after irradiation of cultured hamster cells with 250-kV X rays and with /sup 238/Pu ..cap alpha.. particles. The frequency of mutants induced by these ..cap alpha.. particles, for a given level of cell killing, was approximately twice that induced by X rays. This agrees with expectations from our previously published data on mutation induction by radiations of high linear energy transfer, but disagrees with another recently published report of the relative mutagenicity of /sup 238/Pu ..cap alpha.. particles. Possible reasons for this discrepancy are discussed.

  12. Fire Hose instability driven by alpha particle temperature anisotropy

    E-print Network

    Matteini, Lorenzo; Schwartz, Steven; Landi, Simone

    2015-01-01

    We investigate properties of a solar wind-like plasma including a secondary alpha particle population exhibiting a parallel temperature anisotropy with respect to the background magnetic field, using linear and quasi-linear predictions and by means of one-dimensional hybrid simulations. We show that anisotropic alpha particles can drive a parallel fire hose instability analogous to that generated by protons, but that, remarkably, the instability can be triggered also when the parallel plasma beta of alpha particles is below unity. The wave activity generated by the alpha anisotropy affects the evolution of the more abundant protons, leading to their anisotropic heating. When both ion species have sufficient parallel anisotropies both of them can drive the instability, and we observe generation of two distinct peaks in the spectra of the fluctuations, with longer wavelengths associated to alphas and shorter ones to protons. If a non-zero relative drift is present, the unstable modes propagate preferentially in...

  13. 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 particles from the Tokamak Fusion Test Reactor TFTR K. M. McGuire et al., Phys. Plasmas 2, 2176 1995 has-induced losses result from perturbations to the particle orbits that arise from the magnetic fields of the modes

  14. Particle Physics Aspects of Antihydrogen Studies with ALPHA at CERN

    E-print Network

    Wurtele, Jonathan

    Particle Physics Aspects of Antihydrogen Studies with ALPHA at CERN M.C. Fujiwaraa , G. B the context of the ALPHA experiment at CERN's Antiproton Decelerator facility. We review the fundamental antihydrogen atoms were first produced by the ATHENA [1] and ATRAP [2] experiments in 2002 at CERN's Antiproton

  15. Alpha particle nonionizing energy loss (NIEL) for device applications

    NASA Technical Reports Server (NTRS)

    Jun, Insoo; Xapsos, Michael A.; Messenger, Scott R.; Burke, Edward A.; Walters, Robert J.; Summers, Geoff; Jordan, Thomas

    2004-01-01

    A method developed for the proton NIEL calculation previously is extended to incident alpha particles in this study: ZBL screened potential for Coulomb interactions and MCNPX 'thin target approximation' for nuclear interactions.

  16. Alpha-particle effects on ballooning flute modes in tokamaks

    SciTech Connect

    Andrushchenko, Z.N.; Bijko, A.Y.; Cheremnykh, O.K. )

    1990-11-01

    In this paper a more accurate dispersion equation for ideal ballooning flute modes in a plasma with alpha particles is obtained. It is shown that circulating and trapped alpha particles generate the eigenbranches of the mode oscillations with frequencies {omega} {approx lt} {omega}{sub *i}, where {omega}{sub *i}, is the ion drift frequency. The relevant growth rates and frequencies are found. It is ascertained that in the frequency range {omega}{sub *i} {lt} {omega} {lt} {bar {omega}{sub Db}}, where {bar {omega}{sub Db}} is the magnetic drift frequency average over a bounce period, trapped alpha particles may generate forced oscillations that influence the ideal ballooning flute mode stability boundary. It is shown that the stability may be improved for certain plasma parameters and trapped alpha-particle pressures.

  17. 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.

  18. 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

  19. 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.

  20. Alpha particle behavior, modeling and monitoring using long-range alpha detector (LRAD) technology

    SciTech Connect

    Johnson, J.D.; Allander, K.A.; Bounds, J.A.

    1993-10-01

    Long-Range Alpha Detector (LRAD) systems are used to measure alpha sources by directly measuring the ionization caused by the alpha Particle interaction with air. Two different types of alpha detectors have been developed using LRAD technology: air-flow and fanless detectors. Investigations have been carried out using these detectors to transport properties of the ion pairs created by alpha par-pressures and temperatures in several different gasses. Tests have also being carried out to determine the effects of variation in airflow on detector response. Monte Carlo codes have been written to better model the stopping distance and behavior of alpha particles, beta particles and ions for various source and detector geometries. LRAD detectors have proven to be many times more sensitive than traditional alpha detectors and, therefore, may be used in applications for which a high degree of sensitivity is required. This paper will discuss the results of our tests, as well as the basic LRAD technology and its applications.

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

    NASA Astrophysics Data System (ADS)

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

    1994-10-01

    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.

  2. 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.

  3. {alpha} particles and the ''pasta'' phase in nuclear matter

    SciTech Connect

    Avancini, S. S.; Barros, C. C. Jr.; Menezes, D. P.; Providencia, C.

    2010-08-15

    The effects of the {alpha} particles in nuclear matter at low densities are investigated within three different parametrizations of relativistic models at finite temperature. Both homogeneous and inhomogeneous matter (pasta phase) are described for neutral nuclear matter with fixed proton fractions and stellar matter subject to {beta} equilibrium and trapped neutrinos. In homogeneous matter, {alpha} particles are present only at densities below 0.02 fm{sup -3} and their presence decreases with increase of the temperature and, for a fixed temperature, the {alpha} particle fraction decreases for smaller proton fractions. A repulsive interaction is important to mimic the dissolution of the clusters in homogeneous matter. The effect of the {alpha} particles on the pasta structure is very small except close to the critical temperatures and/or proton fractions, when it may still predict a pasta phase while no pasta phase would occur in the absence of light clusters. It is shown that for densities above 0.01 fm{sup 3} the {alpha}-particle fraction in the pasta phase is much larger than that in homogeneous matter.

  4. 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

  5. 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.

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

    NASA Astrophysics Data System (ADS)

    Myhra, S.; Falzone, N.; Chakalova, R.

    2014-03-01

    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. 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. Chakalova, R.; Falzone, N.

    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.

  8. Performance comparison of scintillators for alpha particle detectors

    NASA Astrophysics Data System (ADS)

    Morishita, Yuki; Yamamoto, Seiichi; Izaki, Kenji; Kaneko, Junichi H.; Toui, Kohei; Tsubota, Youichi; Higuchi, Mikio

    2014-11-01

    Scintillation detectors for alpha particles are often used in nuclear fuel facilities. Alpha particle detectors have also become important in the research field of radionuclide therapy using alpha emitters. ZnS(Ag) is the most often used scintillator for alpha particle detectors because its light output is high. However, the energy resolution of ZnS(Ag)-based scintillation detectors is poor because they are not transparent. A new ceramic sample, namely the cerium doped Gd2Si2O7 (GPS) scintillator, has been tested as alpha particle detector and its performances have been compared to that one of three different scintillating materials: ZnS(Ag), GAGG and a standard plastic scintillator. The different scintillating materials have been coupled to two different photodetectors, namely a photomultiplier tube (PMT) and a Silicon Photo-multiplier (Si-PM): the performances of each detection system have been compared. Promising results as far as the energy resolution performances (10% with PMT and 14% with Si-PM) have been obtained in the case of GPS and GAGG samples. Considering the quantum efficiencies of the photodetectors under test and their relation to the emission wavelength of the different scintillators, the best results were achieved coupling the GPS with the PMT and the GAGG with the Si-PM

  9. 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.

  10. Experimental setup for studying the effects of alpha particles on zebrafish embryos

    E-print Network

    Yu, Peter K.N.

    Experimental setup for studying the effects of alpha particles on zebrafish embryos E.H.W. Yum to study effects of alpha particles on dechorionated zebrafish embryos. Thin PADC films with a thickness substrates for holding zebrafish embryos for alpha-particle irradiation. These films recorded alpha

  11. Fire Hose Instability Driven by Alpha Particle Temperature Anisotropy

    NASA Astrophysics Data System (ADS)

    Matteini, L.; Hellinger, P.; Schwartz, S. J.; Landi, S.

    2015-10-01

    We investigate properties of a solar wind-like plasma, including a secondary alpha particle population exhibiting a parallel temperature anisotropy with respect to the background magnetic field, using linear and quasi-linear predictions and by means of one-dimensional hybrid simulations. We show that anisotropic alpha particles can drive a parallel fire hose instability analogous to that generated by protons, but that, remarkably, can also be triggered when the parallel plasma beta of alpha particles is below unity. The wave activity generated by the alpha anisotropy affects the evolution of the more abundant protons, leading to their anisotropic heating. When both ion species have sufficient parallel anisotropies, both of them can drive the instability, and we observe the generation of two distinct peaks in the spectra of the fluctuations, with longer wavelengths associated to alphas and shorter ones to protons. If a non-zero relative drift is present, the unstable modes propagate preferentially in the direction of the drift associated with the unstable species. The generated waves scatter particles and reduce their temperature anisotropy to a marginally stable state, and, moreover, they significantly reduce the relative drift between the two ion populations. The coexistence of modes excited by both species leads to saturation of the plasma in distinct regions of the beta/anisotropy parameter space for protons and alpha particles, in good agreement with in situ solar wind observations. Our results confirm that fire hose instabilities are likely at work in the solar wind and limit the anisotropy of different ion species in the plasma.

  12. The effect of alpha particles on bacteriophage T4Br+.

    PubMed

    Leont'eva, G A; Akoev, I G; Grigor'ev, A E

    1983-01-01

    It is generally accepted that heavy charged particles play an important part in generating the secondary flux of nuclear particles formed by the interaction of space hadrons with nuclei. It is assumed that these particles are responsible for the high biological efficiency of space hadrons in causing cellular damage by their strong interactions. To examine this assumption we investigated the effects of 5.3 MeV alpha particles on bacteriophage T4. This energy provides a LET value of 88.6 KeV/micrometer lying in the range of the highest biological efficiency. PMID:11542756

  13. TF ripple loss of alpha particles in TFTR DT experiments

    SciTech Connect

    Redi, M.H.; Budny, R.V.; Darrow, D.S.

    1995-08-01

    Quantitative evaluation of TF ripple loss of DT alpha particles is a central issue for reactor design because of potentially severe first wall heat load problems. DT experiments on TFTR allow experimental measurements to be compared to modeling of the underlying alpha physics, with code validation an important goal. Modeling of TF ripple loss of alphas in TFTR now includes neoclassical calculations of alpha losses arising from first orbit loss, stochastic ripple diffusion, ripple trapping and collisional effects. Recent Hamiltonian coordinate guiding center code (ORBIT) simulations for TFTR have shown that collisions enhance the stochastic TF ripple losses at TFTR. A faster way to simulate experiment has been developed and is discussed here which uses a simple stochastic domain model for TF ripple loss within the TRANSP analysis code.

  14. The effects of alpha particle irradiation on stainless steel 

    E-print Network

    Shipp, John Douglas

    1999-01-01

    -surface region of stainless steel as would be produced by alpha particles from WGPu. This value was found to be 4.45E13 ?He? ions/cm² for each year of storage. Rutherford backscattering and channeling analysis was then used to analyze single crystal iron which...

  15. 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

  16. HIGH-TISTABILITY OF ALPHA PARTICLE DRIVEN ALFVEN EIGENMODES

    E-print Network

    Vlad, Gregorio

    , we analyse the two dimensional (2-D) mode structures and global stability of the Alfvkn branches is solved using a two spatial-scale WKBJ formalism without employing perturbation theory in treating drive experiment, in fact, the Alfvkn frequency is of the order of the alpha particle transit frequency [3

  17. Radioadaptive Response Induced by Alpha-Particle-Induced Stress

    E-print Network

    Yu, Peter K.N.

    of radioadaptive response (RAR) by com- munication of radiation-induced bystander signals. RAR is a kind of lowRadioadaptive Response Induced by Alpha-Particle-Induced Stress Communicated in Vivo between and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, and Department

  18. Alpha-particle losses in compact torsatron reactors

    SciTech Connect

    Painter, S.L.; Lyon, J.F.

    1989-01-01

    Loss of alpha particles in compact torsatron reactors is studied. For 6, 9, and 12 field period reactors, the direct loss is a relatively weak function of radius and energy and varies from approx. =33% for M = 6 to approx. =18% for M = 12. Loss of alpha particles through scattering into the loss region is calculated using the Fokker-Plank equation for fast ions and found to contribute an additional alpha-particle energy loss of approx. =15%. The consequences of these relatively large losses for torsatron reactor design are discussed. The relationship between the direct particle losses and the magnetic field structure is also studied. Orbit losses from a variety of stellarator configurations are calculated and a figure-of-merit that characterizes the orbit confinement of a magnetic configuration is deduced from these calculations. This figure-of-merit is used to show how the direct losses might be reduced at low aspect-ratio. Effects of finite beta on the direct particle losses are also addressed, and are shown to significantly increase the direct losses in some configurations. 15 refs., 8 figs.

  19. Michrochannel plate for position sensitive alpha particle detection

    SciTech Connect

    Paul Hurley and James Tinsley

    2007-08-31

    This paper will describe the use of a microchannel plate (MCP) as the associated particle detector on a sealed tube neutron generator. The generator produces neutrons and associated alpha particles for use as a probe to locate and identify hidden explosives in associated particle imaging (API). The MCP measures the position in two dimensions and precise timing of the incident alpha particle, information which is then used to calculate the emission time and direction of the corresponding neutron. The MCP replaces the position-sensitive photomultipler tube (PSPMT) which, until recently, had been the only detector available for measuring position and timing for alpha particles in neutron generator applications. Where the PSPMT uses charge division for generating position information, a process that requires a first order correction to each pulse, the MCP uses delay-line timing, which requires no correction. The result is a device with an order of magnitude improvement in both position resolution and timing compared to the PSPMT. Hardware and software development and the measurements made to characterize the MCP for API applications are described.

  20. LRAD-based alpha-particle contamination monitoring of personnel and equipment

    SciTech Connect

    Macarthur, D.W.; Allander, K.S.; Bounds, J.A.; Mcatee, J.L. )

    1993-05-01

    Traditional alpha-particle contamination monitors are limited in usefulness because of the short range of alpha particles in air. This range limitation makes it impossible to adequately monitor for alpha-particle contamination on uneven surfaces and inside equipment. Personnel must be scanned manually, a procedure that is comparatively uncertain. The long-range alpha detector eliminates many of the difficulties associated with equipment and personnel monitoring by detecting the ions produced by the alpha particles interaction with the air, rather than detecting the alpha particle itself. The personnel and equipment monitors are described in detail, and other potential applications are suggested.

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

    SciTech Connect

    Chang, C.S.; Imre, K.; Weitzner, H.; Colestock, P. . 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.

  2. {alpha} particle preformation in heavy nuclei and penetration probability

    SciTech Connect

    Zhang, H. F.; Royer, G.

    2008-05-15

    The {alpha} particle preformation in the even-even nuclei from {sup 108}Te to {sup 294}118 and the penetration probability have been studied. The isotopes from Pb to U have been firstly investigated since the experimental data allow us to extract the microscopic features for each element. The assault frequency has been estimated using classical methods and the penetration probability from tunneling through the Generalized Liquid Drop Model (GLDM) potential barrier. The preformation factor has been extracted from experimental {alpha} decay energies and half-lives. The shell closure effects play the key role in the {alpha} preformation. The more the nucleon number is close to the magic numbers, the more the formation of {alpha} cluster is difficult inside the mother nucleus. The penetration probabilities reflect that 126 is a neutron magic number. The penetration probability range is very large compared to that of the preformation factor. The penetration probability determines mainly the {alpha} decay half-life while the preformation factor allows us to obtain information on the nuclear structure. The study has been extended to the newly observed heaviest nuclei.

  3. 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.

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

    E-print Network

    Yu, Peter 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

  5. Simple preparation of thin CR-39 detectors for alpha-particle radiobiological experiments

    E-print Network

    Yu, Peter K.N.

    detector, were used for culturing HeLa cells. The feasibility of using these thin CR-39 detectors Alpha-particle radiobiological experiments involve irradiating cells with alpha particles and require accurate positions where the alpha particles hit the cells. In the present work, we prepared thin CR-39

  6. 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…

  7. Alpha particle fusion reaction product modeling in DRACO

    NASA Astrophysics Data System (ADS)

    Moses, Gregory; Yuan, Jiankui

    2003-10-01

    Alpha particle fusion reaction product transport in DRACO is computed using either multi-group flux-limited diffusion theory or continuous energy Monte Carlo particle tracking. Both of these transport models incorporate the same basic slowing down model of Li and Petrasso. Detailed comparisons of particle transport and energy loss predicted by the two models will be presented. Results of 2D lagrangian fusion burn simulations will be compared for the two models. The Monte Carlo model can be used in either an "adiabatic" approximation on each time step or a time dependent model where in-flight particles are remembered for the next time step. Both models are implemented using parallel computing algorithms using the MPI parallel programming interface. Work supported by the Laboratory for Laser Energetics, University of Rochester.

  8. 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.

  9. Interaction of alpha particle beams with metallic glasses

    SciTech Connect

    Sorescu, M.; Barb, D.

    1998-09-18

    Samples of Fe{sub 40}Ni{sub 38}Mo{sub 4}B{sub 18}, Fe{sub 78}B{sub 13}Si{sub 9} and Fe{sub 66}Co{sub 18}B{sub 15}Si{sub 1} metallic glasses, selected with respect to the different values of their magnetostriction constants, were irradiated with alpha particle beams (W = 2.8 MeV) using radiation doses of 10{sup 16} and 10{sup 17}/cm{sup 2}. The fundamental effects underlying the interaction of alpha particle beams with amorphous magnets were studied by transmission and conversion electron Moessbauer spectroscopy (CEMS), hysteresis loops and a.c. susceptibility measurements, and scanning electron microscopy (SEM). 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 behaviors of the magnetic texture and constituent phases were evidenced. Radiation-driven changes in the saturation magnetic moment, coercive field, real and imaginary components of the a.c. response were observed for all samples studied and found to depend on the radiation dose employed. The surface morphology of the radiation-induced crystalline precipitates was shown to vary as a function of composition, such that both spherical and dendritical modes of growth were observed. By stimulating unconventional pathways for the crystallization process, the interaction of alpha particle beams with glassy ferromagnets offers unique opportunities to understand the fundamentals of nucleation and growth in these systems.

  10. Energetic alpha particle deposition in a magnetized plasma

    SciTech Connect

    Smitherman, D.P.; Kirkpatrick, R.C.

    1991-01-01

    The problem of energetic alpha particle deposition in a dense, magnetized deuterium-tritium (DT) thermonuclear fuel has been studied numerically for the case of coulomb interactions in cylindrical geometry. This was done by following the particle trajectories initiated at various radii and in different directions through the plasma and its imposed field until they had either left the plasma or deposited all their energy. The resulting complex particle trajectories in the static magnetized fuel make a detailed treatment of the problem computationally intensive. Therefore, we have attempted to use detailed modeling to produce a data base for a neural nets algorithm for incorporation in an ignition critical profile code. While the accuracy of the neutral net in reproducing the detailed calculational results is not high, it is approximately 6000 times faster. 7 refs., 1 fig.

  11. Control of alpha particle transport by spatially inhomogeneous ion cyclotron resonance heating

    SciTech Connect

    Chang, C.S.; Imre, K.; Weitzner, H. . Courant Inst. of Mathematical Sciences); Colestock, P. . Plasma Physics Lab.)

    1990-02-01

    Control of the radial alpha particle transport by using Ion Cyclotron Range of Frequency waves is investigated in a large-aspect-ratio tokamak geometry. It is shown that spatially inhomogeneous ICRF-wave energy with properly selected frequencies and wave numbers can induce fast convective transport of alpha particles at the speed of order {upsilon}{sub alpha} {approximately} (P{sub RF}/n{sub {alpha}}{epsilon}{sub 0}) {rho}{sub p}, where P{sub RF} is the ICRF-wave power density, n{sub {alpha}} is the alpha density, {epsilon}{sub 0} is the alpha birth energy, and {rho}{sub p} is the poloidal gyroradius of alpha particles at the birth energy. Application to ITER plasmas is studied and possible antenna designs to control alpha particle flux are discussed. 8 refs., 3 figs.

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

    SciTech Connect

    Reed, D.T.; Hoh, J.; Emery, J. ); Hobbs, D. )

    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.

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

    SciTech Connect

    Reed, D.T.; Hoh, J.; Emery, J.; Hobbs, D.

    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.

  14. Sawtooth mixing of alpha particles in TFTR D-T plasmas

    SciTech Connect

    Petrov, M.P.; Budny, R.V.; Chang, Z.

    1996-12-31

    Radially resolved confined alpha particle energy and density distributions are routinely measured on TFTR using two diagnostics: PCX and {alpha}-CHERS. The Pellet Charge-eXchange (PCX) diagnostic uses the ablation cloud formed by an impurity pellet (Li or B) for neutralization of the alphas followed by analysis of the escaping helium neutrals. PCX detects deeply trapped alpha particles in the energy range 0.5 - 3.8 MeV. The {alpha}-CHERS technique, were the alpha signal is excited by charge-exchange between alphas and the deuterium atoms of one of the heating beams and appears as a wing on the He{sup +} 468.6 nm line, detects mainly passing alphas in the range of 0.15 - 0.7 MeV. Studies of alpha losses during DT experiments on TFTR have also been conducted using lost alpha detectors located on the walls of the plasma chamber. All of these diagnostics were used for investigating the influence of sawtooth crashes on alphas in high power D-T discharges in TFTR. Both PCX and {alpha}-CHERS measurements show a strong depletion of the alpha core density and transport of trapped alphas radially outwards well beyond q = 1 surface after a sawtooth crash. Lost alpha detectors measure bursts of alpha loss of the previously confined alphas (<1%). Thus, a sawtooth crash leads mainly to radial redistribution of the alphas rather than losses. For modeling of alpha sawtooth mixing, a code is used which is based on the conventional model of magnetic reconnection and the conservation of particles, energy and magnetic flux. The effect of the particle orbit averaged toroidal drift in a perturbed helical electric field generated by the crash has also been included in the code. It is shown that mixing of the passing alphas is dominated by the magnetic reconnection whereas trapped alphas are affected mainly by ExB drift.

  15. Detection of alpha particles using DNA/Al Schottky junctions

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

    Deoxyribonucleic acid or DNA can be utilized in an organic-metallic rectifying structure to detect radiation, especially alpha particles. This has become much more important in recent years due to crucial environmental detection needs in both peace and war. In this work, we fabricated an aluminum (Al)/DNA/Al structure and generated current-voltage characteristics upon exposure to alpha radiation. Two models were utilized to investigate these current profiles; the standard conventional thermionic emission model and Cheung and Cheung's method. Using these models, the barrier height, Richardson constant, ideality factor and series resistance of the metal-DNA-metal structure were analyzed in real time. The barrier height, ? value calculated using the conventional method for non-radiated structure was 0.7149 eV, increasing to 0.7367 eV after 4 min of radiation. Barrier height values were observed to increase after 20, 30 and 40 min of radiation, except for 6, 8, and 10 min, which registered a decrease of about 0.67 eV. This was in comparison using Cheung and Cheung's method, which registered 0.6983 eV and 0.7528 eV for the non-radiated and 2 min of radiation, respectively. The barrier height values, meanwhile, were observed to decrease after 4 (0.61 eV) to 40 min (0.6945 eV). The study shows that conventional thermionic emission model could be practically utilized for estimating the diode parameters including the effect of series resistance. These changes in the electronic properties of the Al/DNA/Al junctions could therefore be utilized in the manufacture of sensitive alpha particle sensors.

  16. Preliminary results from the lunar prospector alpha particle spectrometer

    SciTech Connect

    Lawson, S. L.

    2001-01-01

    The Lunar Prospector Alpha Particle Spectrometer (LP APS) builds on Apollo heritage and maps the distribution of outgassing sites on the Moon. The APS searches for lunar surface gas release events and maps their distribution by detecting alpha particles produced by the decay of gaseous radon-222 (5.5 MeV, 3.8 day half-life) and solid polonium-210 (5.3 MeV, 138 day half-life, but remains on the surface with a 21 year half-life as lead-210), which are radioactive daughters from the decay of uranium-238. Radon is in such small quantities that it is not released directly from the lunar interior, rather it is entrained in a stream of gases and serves as a tracer for such gases. Once released, the radon spreads out by 'bouncing' across the surface on ballistic trajectories in a random-walk process. The 3.8 day half-life of radon-222 allows the gas to spread out by several 100 km before it decays and allows the APS to detect gas release events up to a few days after they occur. The long residence time (10s of years) of the lead-210 precursor to the polonium-210 allows the mapping of gas vents which have been active over the last approximately 50 years. Because radon and polonium are daughter products of the decay of uranium, the background level of alpha particle activity is a function of the lunar crustal uranium distribution. Using radioactive radon and polonium as tracers, the Apollo 15 and 16 Command Module orbital alpha particle experiments obtained evidence for the release of gases at several sites beneath the orbit tracks, especially over the Aristarchus Plateau and Mare Fecunditatis [1]. Aristarchus crater had previously been identified by ground-based observers as the site of transient optical events [2]. The Apollo 17 surface mass spectrometer showed that argon-40 is released from the lunar interior every few months, apparently in concert with some of the shallow moonquakes that are believed to be of tectonic origin [3]. The latter tectonic events could be associated with very young scarps identified in the lunar highlands [4] and are believed to indicate continued global contraction. Such quakes could open fissures leading to the release of gases that are trapped below the surface. The detection of radon-222 outgassing events at the margins of Fecunditatis basin was surprising because the observed surface distribution of uranium and thorium do not extend sufficiently eastward to cover Fecunditatis. If the Apollo detections prove sound, then those alpha particle emissions indicate substantial subsurface concentrations of uranium-238 within Fecunditatis. A primary goal of the APS was to map gas-release events, thus allowing both an appraisal of the current level of tectonic activity on the Moon and providing a probe of subsurface uranium concentrations.

  17. INSTABILITIES DRIVEN BY THE DRIFT AND TEMPERATURE ANISOTROPY OF ALPHA PARTICLES IN THE SOLAR WIND

    SciTech Connect

    Verscharen, Daniel; Bourouaine, Sofiane; Chandran, Benjamin D. G. E-mail: s.bourouaine@unh.edu

    2013-08-20

    We investigate the conditions under which parallel-propagating Alfven/ion-cyclotron (A/IC) waves and fast-magnetosonic/whistler (FM/W) waves are driven unstable by the differential flow and temperature anisotropy of alpha particles in the solar wind. We focus on the limit in which w{sub Parallel-To {alpha}} {approx}> 0.25v{sub A}, where w{sub Parallel-To {alpha}} is the parallel alpha-particle thermal speed and v{sub A} is the Alfven speed. We derive analytic expressions for the instability thresholds of these waves, which show, e.g., how the minimum unstable alpha-particle beam speed depends upon w{sub Parallel-To {alpha}}/v{sub A}, the degree of alpha-particle temperature anisotropy, and the alpha-to-proton temperature ratio. We validate our analytical results using numerical solutions to the full hot-plasma dispersion relation. Consistent with previous work, we find that temperature anisotropy allows A/IC waves and FM/W waves to become unstable at significantly lower values of the alpha-particle beam speed U{sub {alpha}} than in the isotropic-temperature case. Likewise, differential flow lowers the minimum temperature anisotropy needed to excite A/IC or FM/W waves relative to the case in which U{sub {alpha}} = 0. We discuss the relevance of our results to alpha particles in the solar wind near 1 AU.

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

    E-print Network

    Yu, Peter 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

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

    E-print Network

    1 PPPL-3164 - Preprint Date: January 1996, UC-420 Alpha Particle Losses from Tokamak Fusion Test on tokamak reactor viability, the loss of deuterium-tritium alpha particles from the Tokamak Fusion Test from perturba- tions to the particle orbits which arise from the magnetic fields of the modes. Any sort

  20. Study of backscattering in alpha-particle sources with the new code AlfaMC

    NASA Astrophysics Data System (ADS)

    Vargas, M. Jurado; Timón, A. Fernández

    2015-01-01

    The activity of alpha-particle sources with negligible thickness can be absolutely determined using 2? counting geometry detectors, requiring corrections for backscattering from the source backing. The experimental determination of these corrections is subject to large uncertainties, because the contribution of the backscattered alpha particles to the total counting is generally very low. An interesting alternative is then to use Monte Carlo methods which simulate the transport of alpha-particles into the source. The programme AlfaMC, a new Monte Carlo code developed to simulate specifically the transport of alpha particles, was here applied to the study of the backscattering in alpha-particle sources. Energy and angular distributions for the backscattered alpha particles were deeply analysed based on a multiple scattering process, as a result of a large number of weak collisions with atomic electrons. Some calculated values for the backscattering coefficient were compared with experimental values, showing a good agreement.

  1. 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.

  2. Breakup of {sup 12}C resonances into three alpha particles

    SciTech Connect

    Kirsebom, O. S.; Fynbo, H. O. U.; Hyldegaard, S.; Riisager, K.; Alcorta, M.; Borge, M. J. G.; Cubero, M.; Dominguez-Reyes, R.; Madurga, M.; Perea, A.; Tengblad, O.; Diget, C. A.; Fulton, B. R.; Fraile, L. M.; Jonson, B.; Nilsson, T.; Nyman, G.; Munoz Martin, A.

    2010-06-15

    The reaction {sup 3}He+{sup 11}B->d+{sup 12}C* has been used to populate resonances in {sup 12}C up to an excitation energy of 15 MeV. The subsequent breakup to three alpha particles has been measured in complete kinematics. Dalitz plots are used to visualize and analyze the data. The Dalitz plot intensity distribution exhibits zero points characteristic of the total spin and parity of the 3alpha system allowing us to determine the spin and parity of a state in {sup 12}C at 13.35 MeV whose quantum numbers were hitherto not well established. The Dalitz plot intensity distributions of the 2{sup -} state at 11.83 MeV and the 1{sup +} state at 12.71 MeV are compared with the predictions of a recent three-body calculation as well as with simpler models. All are able to reproduce the gross structures seen in the Dalitz plot, but none give an accurate description of the detailed profile of the distributions.

  3. Ionization of sodium by the impact of alpha particle

    NASA Astrophysics Data System (ADS)

    Bhattacharya, S.; Choudhury, K. B.; Deb, N. C.; Sinha, C.; Roy, K.; Msezane, A. Z.

    2008-05-01

    A one channel distorted wave approximation has been used to calculate the ionization cross section for the 3s electron of Na atom by alpha particle impact. For a consistency check we have also run the standard CDW-EIS code of McSherry et al. [Comput. Phys. Commun. 155, 144 (2003)] and found reasonable agreement in the high energy region among the present results, the CDW-EIS results and the classical trajectory Monte Carlo (CTMC) calculations. It is also found that the present results tend to agree qualitatively with the low energy measurement of Knoop et al. [J. Phys. B 38, 1987 (2005)] at as low as 10 keV amu-1, although the present theoretical approach is expected to be suitable in the high energy area. This qualitative agreement in the low energy region is attributed to the partially correlated ground state wave function used in the present calculation.

  4. Detection of lost alpha particle by concealed lost ion probe

    SciTech Connect

    Okamoto, A.; Kitajima, S.; Sasao, M.; Isobe, M.

    2010-10-15

    Full orbit-following calculation is performed for the final orbit of the lost alpha particles, showing some orbits escaping from the last closed flux surface could be detected by a concealed lost ion probe (CLIP) installed under the shadow of the original first wall surface. While both passing and trapped orbits hit the same wall panel, detecting a trapped orbit by the CLIP is easier than detecting passing orbits. Whether the final orbit is detected or not is determined by the position of the reflection point. The CLIP successfully detects the trapped orbits, which are reflected before they hit to a first wall. Then the pitch angles of the orbits at the CLIP are close to and smaller than 90 deg. Optimization of the position of the CLIP in terms of broader detection window is investigated.

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

    PubMed Central

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

    2013-01-01

    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 (225Ac) is an alpha particle-emitting radionuclide that generates 4 net alpha particle isotopes in a short decay chain to stable 209Bi, 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 225Ac to potently and specifically affect cancer. PMID:18514364

  6. 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

  7. 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.

  8. Experimental Study of the Cross Sections of {alpha}-Particle Induced Reactions on 209Bi

    SciTech Connect

    Hermanne, A.; Tarkanyi, F.; Takacs, S.; Szucs, Z.

    2005-05-24

    Alpha particle induced reactions for generation of 211At used in therapeutic nuclear medicine and possible contaminants were investigated with the stacked foil activation technique on natural bismuth targets up to E{alpha}=39 MeV. Excitation functions for the reactions 209Bi({alpha},2n)211At, 209Bi({alpha},3n)210At, 209Bi({alpha},x) 210Po obtained from direct alpha emission measurements and gamma spectra from decay products are compared with earlier literature values. Thick target yields have been deduced from the experimental cross sections.

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

    E-print Network

    CURRENT DRIVE BY LOWER HYBRID WAVES IN THE PRESENCE OF ENERGETIC ALPHA PARTICLES N.J. FISCH, J of America ABSTRACT. Many experiments have proved the effectiveness of lower hybrid waves for driving by electrons. The paper addresses mathematically the interaction between lower hybrid waves and alpha particles

  10. Induction of a bystander mutagenic effect of alpha particles in mammalian cells

    E-print Network

    Induction of a bystander mutagenic effect of alpha particles in mammalian cells Hongning Zhou selected AL cells with 20 alpha particles each results in a mutant fraction that is 3-fold higher than of cells with the radical scavenger DMSO had no effect on the mutagenic incidence. In contrast, cells

  11. {alpha}-particle production in {sup 6}He+{sup 120}Sn collisions

    SciTech Connect

    Faria, P. N. de; Lichtenthaeler, R.; Pires, K. C. C.; Lepine-Szily, A.; Guimaraes, V.; Mendes, D. R. Jr.; Barioni, A.; Morcelle, V.; Morais, M. C.; Moro, A. M.; Arazi, A.

    2010-09-15

    The collision {sup 6}He+{sup 120}Sn has been investigated at four energies near the Coulomb barrier. A large yield of {alpha} particles has been detected, with energies around the energy of the scattered {sup 6}He beam. The energy and angular distributions of the {alpha} particles have been analyzed and compared with breakup and neutron transfer calculations.

  12. 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.

  13. Excitation of high-n toroidicity-induced shear Alfven eigenmodes by energetic particles and fusion alpha particles in tokamaks

    SciTech Connect

    Fu, G.Y.; Cheng, C.Z.

    1992-07-01

    The stability of high-n toroidicity-induced shear Alfven eigenmodes (TAE) in the presence of fusion alpha particles or energetic ions in tokamaks is investigated. The TAE modes are discrete in nature and thus can easily tap the free energy associated with energetic particle pressure gradient through wave particle resonant interaction. A quadratic form is derived for the high-n TAE modes using gyro-kinetic equation. The kinetic effects of energetic particles are calculated perturbatively using the ideal MHD solution as the lowest order eigenfunction. The finite Larmor radius (FLR) effects and the finite drift orbit width (FDW) effects are included for both circulating and trapped energetic particles. It is shown that, for circulating particles, FLR and FDW effects have two opposite influences on the stability of the high-n TAE modes. First, they have the usual stabilizing effects by reducing the wave particle interaction strength. Second, they also have destabilizing effects by allowing more particles to resonate with the TAE modes. It is found that the growth rate induced by the circulating alpha particles increase linearly with toroidal mode number n for small {kappa}{sub {theta}}{rho}{sub {alpha}}, and decreases as 1/n for {kappa}{sub {theta}}{rho}{sub {alpha}} {much_gt} 1. The maximum growth rate is obtained at {kappa}{sub {theta}}{rho}{sub {alpha}} on the order of unity and is nearly constant for the range of 0.7 < {upsilon}{sub {alpha}}/{upsilon}{sub A} < 2.5. On the other hand, the trapped particle response is dominated by the precessional drift resonance. The bounce resonant contribution is negligible. The growth rate peaks sharply at the value of {kappa}{sub {theta}}{rho}{sub {alpha}} such that the precessional drift resonance occurs for the most energetic trapped particles. The maximum growth rate due to the energetic trapped particles is comparable to that of circulating particles.

  14. Excitation of high-n toroidicity-induced shear Alfven eigenmodes by energetic particles and fusion alpha particles in tokamaks

    SciTech Connect

    Fu, G.Y.; Cheng, C.Z.

    1992-07-01

    The stability of high-n toroidicity-induced shear Alfven eigenmodes (TAE) in the presence of fusion alpha particles or energetic ions in tokamaks is investigated. The TAE modes are discrete in nature and thus can easily tap the free energy associated with energetic particle pressure gradient through wave particle resonant interaction. A quadratic form is derived for the high-n TAE modes using gyro-kinetic equation. The kinetic effects of energetic particles are calculated perturbatively using the ideal MHD solution as the lowest order eigenfunction. The finite Larmor radius (FLR) effects and the finite drift orbit width (FDW) effects are included for both circulating and trapped energetic particles. It is shown that, for circulating particles, FLR and FDW effects have two opposite influences on the stability of the high-n TAE modes. First, they have the usual stabilizing effects by reducing the wave particle interaction strength. Second, they also have destabilizing effects by allowing more particles to resonate with the TAE modes. It is found that the growth rate induced by the circulating alpha particles increase linearly with toroidal mode number n for small {kappa}{sub {theta}}{rho}{sub {alpha}}, and decreases as 1/n for {kappa}{sub {theta}}{rho}{sub {alpha}} {much gt} 1. The maximum growth rate is obtained at {kappa}{sub {theta}}{rho}{sub {alpha}} on the order of unity and is nearly constant for the range of 0.7 < {upsilon}{sub {alpha}}/{upsilon}{sub A} < 2.5. On the other hand, the trapped particle response is dominated by the precessional drift resonance. The bounce resonant contribution is negligible. The growth rate peaks sharply at the value of {kappa}{sub {theta}}{rho}{sub {alpha}} such that the precessional drift resonance occurs for the most energetic trapped particles. The maximum growth rate due to the energetic trapped particles is comparable to that of circulating particles.

  15. 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.; Belyaev, A.A.; Lukhanin, A.A.; Noga, V.I.; Erzinkyan, A.L.; Parfenova, V.P.; Eversheim, P.-D.; Herzog, P.; Tramm, C.; Filimonov, V.T.; Toporov, Yu.G.; Zotov, E.; Gurevich, G.M.; Rusakov, A.V.; Vyachin, V.N.; Zakoucky, D.

    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.

  16. High-resolution alpha-particle spectrometry of the 230U decay series.

    PubMed

    Marouli, M; Pommé, S; Paepen, J; Van Ammel, R; Jobbágy, V; Dirican, A; Suliman, G; Stroh, H; Apostolidis, C; Abbas, K; Morgenstern, A

    2012-09-01

    High-resolution alpha-particle spectrometry was performed on the (230)U decay series. A (230)U source was prepared on a stainless steel disc by electrodeposition in an ammonium nitrate solution. Spectrometry of the alpha-particle energy spectrum was performed with ion-implanted planar silicon detectors in vacuum. A set of alpha emission probabilities is presented for (230)U and (226)Th. The measured peak intensities were corrected mathematically for coincidental detection of alpha-particles and conversion electrons emitted in the same decay. A good agreement with literature data was observed. The uncertainty budget and the correlation matrix are presented. The validity of the alpha-particle energies was tested and could be confirmed for most peaks within a few keV, but discrepancies were found for the 2nd peak of (226)Th and the main peak of (218)Rn. PMID:22424835

  17. Observation of sawtooth redistribution of nonthermal, confined alpha particles in TFTR D-T discharges

    SciTech Connect

    Stratton, B.; Budny, R.; Chang, Z.; Fonck, R.; Wising, F.; Odblom, A.

    1996-05-01

    Radial profiles of the density of confined alpha particles with energies in the 0.15-0.6 MeV range are spectroscopically observed before and after a sawtooth crash in a TFTR D-T plasma. A large drop in the core alpha density is seen indicating expulsion of alphas from the core to the plasma periphery. The measured changes in the alpha density profiles are consistent with predictions based on the Kolesnichenko sawtooth model, indicating that it may be used to reliably predict the effect of sawteeth on fusion-produced alphas.

  18. The interaction of energetic alpha-particles with intense lower hybrid waves

    SciTech Connect

    Fisch, N.J.; Rax, J.M.

    1992-06-01

    Lower hybrid waves are a demonstrated, continuous means of driving toroidal current in a tokamak. When these waves propagate in a tokamak fusion reactor, in which there are energetic {alpha}- particles, there are conditions under which the {alpha}-particles do not appreciably damp, and may even amplify, the wave, thereby enhancing the current-drive effect. Waves traveling in one poloidal direction, in addition to being directed in one toroidal direction, are shown to be the most efficient drivers of current in the presence of the energetic {alpha}-particles.

  19. On the approximations of the distribution function of fusion alpha particles

    SciTech Connect

    Bilato, R. Brambilla, M.; Poli, E.

    2014-10-15

    The solution of the drift-kinetic equation for fusion-born alpha particles is derived in the limit of dominant parallel streaming, and it is related to the usual slowing-down distribution function. The typical approximations of the fast tail of fusion-born alpha particles are briefly compared and discussed. In particular, approximating the distribution function of fast-alpha particles with an “equivalent” Maxwellian is inaccurate to describe absorption of radio-frequency waves in the ion-cyclotron range of frequencies.

  20. Method for characterizing the upset response of CMOS circuits using alpha-particle sensitive test circuits

    NASA Technical Reports Server (NTRS)

    Buehler, Martin G. (Inventor); Blaes, Brent R. (Inventor); Nixon, Robert H. (Inventor); Soli, George A. (Inventor)

    1995-01-01

    A method for predicting the SEU susceptibility of a standard-cell D-latch using an alpha-particle sensitive SRAM, SPICE critical charge simulation results, and alpha-particle interaction physics. A technique utilizing test structures to quickly and inexpensively characterize the SEU sensitivity of standard cell latches intended for use in a space environment. This bench-level approach utilizes alpha particles to induce upsets in a low LET sensitive 4-k bit test SRAM. This SRAM consists of cells that employ an offset voltage to adjust their upset sensitivity and an enlarged sensitive drain junction to enhance the cell's upset rate.

  1. PPPL3164 Preprint Date: January 1996, UC420 Alpha Particle Losses from Tokamak Fusion Test Reactor

    E-print Network

    1 PPPL­3164 ­ Preprint Date: January 1996, UC­420 Alpha Particle Losses from Tokamak Fusion Test particles from the Tokamak Fusion Test Reactor (TFTR) has been measured under a wide range of conditions of the tokamak's magnetic geometry and such losses may be computed by following orbits of individual particles

  2. 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.

  3. 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.

  4. Design of a neutron-TPC prototype and its performance evaluation based on an alpha-particle test

    NASA Astrophysics Data System (ADS)

    Huang, Meng; Li, Yu-Lan; Niu, Li-Bo; Li, Jin; Deng, Zhi; He, Li; Zhang, Hong-Yan; Cheng, Xiao-Lei; Fu, Jian-Qiang; Li, Yuan-Jing

    2015-08-01

    A neutron-TPC (nTPC) is being developed for use as a fast neutron spectrometer in the fields of nuclear physics, nuclear reactor operation monitoring, and thermo-nuclear fusion plasma diagnostics. An nTPC prototype based on a GEM-TPC (Time Projection Chamber with Gas Electron Multiplier amplification) has been assembled and tested using argon-hydrocarbon mixture as the working gas. By measuring the energy deposition of the recoil proton in the sensitive volume and the angle of the proton track, the incident neutron energy can be deduced. A Monte Carlo simulation was carried out to analyze the parameters affecting the energy resolution of the nTPC, and gave an optimized resolution under ideal conditions. An alpha particle experiment was performed to verify its feasibility, and to characterize its performance, including energy resolution and spatial resolution. Based on the experimental measurement and analysis, the energy resolution (FWHM) of the nTPC prototype is predicted to be better than 3.2% for 5 MeV incident neutrons, meeting the performance requirement (FWHM<5%) for the nTPC prototype.

  5. PPPL3119 Preprint: July 1995, UC426 Alfvnic Behavior of Alpha Particle Driven Ion Cyclotron

    E-print Network

    PPPL­3119 ­ Preprint: July 1995, UC­426 Alfvénic Behavior of Alpha Particle Driven Ion Cyclotron, Oxfordshire, OX14 3DB UK (Euratom/UKAEA Fusion Association) ABSTRACT Ion cyclotron emission (ICE) has been the top and bottom of the vacuum vessel. Harmonics of the alpha cyclotron frequency (W a ) evaluated

  6. PPPL-3119 -Preprint: July 1995, UC-426 Alfvnic Behavior of Alpha Particle Driven Ion Cyclotron

    E-print Network

    PPPL-3119 - Preprint: July 1995, UC-426 Alfvénic Behavior of Alpha Particle Driven Ion Cyclotron, Oxfordshire, OX14 3DB UK (Euratom/UKAEA Fusion Association) ABSTRACT Ion cyclotron emission (ICE) has been the top and bottom of the vacuum vessel. Harmonics of the alpha cyclotron frequency ( ) evaluated

  7. 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.

  8. Interaction of neutrons with alpha particles: A tribute to Heinz Barschall

    E-print Network

    B. Hoop

    2015-03-16

    As a tribute to our teacher and mentor on the occasion of his centennial celebration, we provide a brief historical overview and a summary of sustained interest in the topic of interaction of neutrons with alpha particles.

  9. 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 ...

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

    SciTech Connect

    Matsuura, H.; Nakao, Y.

    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.

  11. Calculations of alpha particle loss for reversed magnetic shear in the Tokamak Fusion Test Reactor

    SciTech Connect

    Redi, M.H.; White, R.B.; Batha, S.H.; Levinton, F.M.; McCune, D.C.

    1997-03-01

    Hamiltonian coordinate, guiding center code calculations of the toroidal field ripple loss of alpha particles from a reversed shear plasma predict both total alpha losses and ripple diffusion losses to be greater than those from a comparable non-reversed magnetic shear plasma in the Tokamak Fusion Test Reactor (TFTR) [Fusion Technol. 21, 1324 (1992)]. High central q is found to increase alpha ripple losses as well as first orbit losses of alphas in the reversed shear simulations. A simple ripple loss model, benchmarked against the guiding center code, is found to work satisfactorily in transport analysis modelling of reversed and monotonic shear scenarios. Alpha ripple transport on TFTR affects ions within r/a=0.5, not at the plasma edge. The entire plasma is above threshold for stochastic ripple loss of alpha particles at birth energy in the reversed shear case simulated, so that all trapped 3.5 MeV alphas are lost stochastically or through prompt losses. The 40% alpha particle loss predictions for TFTR suggest that reduction of toroidal field ripple will be a critical issue in the design of a reversed shear fusion reactor.

  12. Studies of biocompatibility of chemically etched CR-39 SSNTDs in view of their applications in alpha-particle radiobiological experiments

    E-print Network

    Yu, Peter K.N.

    of the cultured HeLa cells. The wetting properties of these etched CR-39 SSNTDs are also studied. The moderately-state nuclear track detector; CR-39; Etching; Radiobiology; Alpha particle; HeLa cells 1. Introduction Alpha online 13 June 2006 Abstract Alpha-particle radiobiological experiments involve irradiating cells

  13. 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

  14. 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.

  15. 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.

  16. 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).

  17. TCAD simulation for alpha-particle spectroscopy using SIC Schottky diode.

    PubMed

    Das, Achintya; Duttagupta, Siddhartha P

    2015-12-01

    There is a growing requirement of alpha spectroscopy in the fields context of environmental radioactive contamination, nuclear waste management, site decommissioning and decontamination. Although silicon-based alpha-particle detection technology is mature, high leakage current, low displacement threshold and radiation hardness limits the operation of the detector in harsh environments. Silicon carbide (SiC) is considered to be excellent material for radiation detection application due to its high band gap, high displacement threshold and high thermal conductivity. In this report, an alpha-particle-induced electron-hole pair generation model for a reverse-biased n-type SiC Schottky diode has been proposed and verified using technology computer aided design (TCAD) simulations. First, the forward-biased I-V characteristics were studied to determine the diode ideality factor and compared with published experimental data. The ideality factor was found to be in the range of 1.4-1.7 for a corresponding temperature range of 300-500 K. Next, the energy-dependent, alpha-particle-induced EHP generation model parameters were optimised using transport of ions in matter (TRIM) simulation. Finally, the transient pulses generated due to alpha-particle bombardment were analysed for (1) different diode temperatures (300-500 K), (2) different incident alpha-particle energies (1-5 MeV), (3) different reverse bias voltages of the 4H-SiC-based Schottky diode (-50 to -250 V) and (4) different angles of incidence of the alpha particle (0°-70°).The above model can be extended to other (wide band-gap semiconductor) device technologies useful for radiation-sensing application. PMID:25634901

  18. Effects of q(r) on the Alpha Particle Ripple Loss in TFTR

    SciTech Connect

    D.S. Darrow; M. Diesso; R.V. Budny; S. Batha; S.J. Zweben; et al.

    1997-09-01

    An experiment was done with TFTR DT plasmas to determine the effect of the q(r) profile on the alpha particle ripple loss to the outer midplane. The alpha particle loss measurements were made using a radially movable scintillator detector 20 degrees below the outer midplane. The experimental results were compared with TF ripple loss calculations done using a Monte Carlo guiding center orbit following code, ORBIT. Although some of the experimental results are consistent with the ORBIT code modeling, the variation of the alpha loss with the q(r) profiles is not well explained by this code. Quantitative interpretation of these measurements requires a careful analysis of the limiter shadowing effect, which strongly determines the diffusion of alphas into the detector aperture.

  19. Alpha-particle-induced bystander effects between zebrafish embryos in vivo E.H.W. Yum a

    E-print Network

    Yu, Peter K.N.

    Alpha-particle-induced bystander effects between zebrafish embryos in vivo E.H.W. Yum a , V Keywords: Bystander effect Alpha particles Zebrafish embryos PADC a b s t r a c t Dechorionaed embryos-particle-induced bystander effects between zebrafish embryos in vivo, and a general positive correlation between the cell

  20. Fusion alpha-particle diagnostics for DT experiments on the joint European torus

    SciTech Connect

    Kiptily, V. G.; Beaumont, P.; Syme, D. B.; Cecil, F. E.; Riva, M.; Conroy, S.; Ericsson, G.; Craciunescu, T.; Garcia-Munoz, M.; Curuia, M.; Soare, S.; Darrow, D.; Fernandes, A. M.; Pereira, R. C.; Sousa, J.; Gorini,; Nocente, M.; and others

    2014-08-21

    JET equipped with ITER-like wall (a beryllium wall and a tungsten divertor) can provide auxiliary heating with power up to 35MW, producing a significant population of ?-particles in DT operation. The direct measurements of alphas are very difficult and ?-particle studies require a significant development of dedicated diagnostics. JET now has an excellent set of confined and lost fast particle diagnostics for measuring the ?-particle source and its evolution in space and time, ?-particle energy distribution, and ?-particle losses. This paper describes how the above mentioned JET diagnostic systems could be used for ?-particle measurements, and what options exist for keeping the essential ?-particle diagnostics functioning well in the presence of intense DT neutron flux. Also, ?-particle diagnostics for ITER are discussed.

  1. Alpha particle heating in hot diamagnetic cavities. [in solar wind near earth's bow shock

    NASA Technical Reports Server (NTRS)

    Galvez, Miguel; Fuselier, Stephen A.; Gary, S. Peter; Thomsen, Michelle F.; Winske, Dan

    1990-01-01

    Observational data from ISEE 1 are analyzed and a one-dimensional electromagnetic hybrid computer simulation is conducted for the heating of solar wind alpha particles in hot diamagnetic cavities (HDCs). In the simulation, which envisions alpha heating by ion-ion instabilities, low beam densities excite the proton/proton right-hand resonant instability that then pitch-angle scatters the beam without significantly heating the alphas. At greater beam densities, the proton/proton nonresonant instability undergoes saturation through a trapping of all three ion components. These results support the Thomsen et al. (1988) hypothesis that the nonresonant instability is the primary source of ion heating in hot diamagnetic cavities.

  2. 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.

  3. 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

  4. 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.

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

    E-print Network

    Chakravarty, Aniruddha

    2015-01-01

    Heating of polar coronal holes 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 collision-less region of the polar coronal holes. In this article, we have presented a novel sensitivity analysis to investigate plasma heating by radio waves at lower hybrid frequencies. We have employed a three fluid Maxwell model comprising electrons, protons, and alpha particles at around two solar radius heliocentric distance in the polar coronal holes and derived a dispersion relation as a thirteenth order polynomial for the frequency. Our model provides indications of preferential heating of alpha particles in comparison with protons by means of lower hybrid 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 differen...

  6. On the correlation between the binding energies of the triton and the alpha-particle

    E-print Network

    L. Platter; H. -W. Hammer; U. -G. Meißner

    2004-11-22

    We consider the correlation between the binding energies of the triton and the alpha-particle which is empirically observed in calculations employing different phenomenological nucleon-nucleon interactions. Using an effective quantum mechanics approach for short-range interactions with large scattering length |a| >> l, where l is the natural low-energy length scale, we construct the effective interaction potential at leading order in l/|a|. In order to renormalize the four-nucleon system, it is sufficient to include a SU(4)-symmetric one-parameter three-nucleon interaction in addition to the S-wave nucleon-nucleon interactions. The absence of a four-nucleon force at this order explains the empirically observed correlation between the binding energies of the triton and the alpha-particle. We calculate this correlation and obtain a prediction for the alpha-particle binding energy. Corrections to our results are suppressed by l/|a|.

  7. 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

  8. 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

  9. 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

  10. Energy and frequency dependence of the alpha particle redistribution produced by internal kink modes

    SciTech Connect

    Farengo, R.; Ferrari, H. E.; Garcia-Martinez, P. L.; Firpo, M.-C.; Ettoumi, W.; Lifschitz, A. F.

    2014-08-15

    The redistribution of alpha particles due to internal kink modes is studied. The exact particle trajectories in the total fields, equilibrium plus perturbation, are calculated. The equilibrium has circular cross section and the plasma parameters are similar to those expected in ITER. The alpha particles are initially distributed according to a slowing down distribution function and have energies between 18?keV and 3.5?MeV. The (1, 1), (2, 2), and (2, 1) modes are included and the effect of changing their amplitude and frequency is studied. When only the (1, 1) mode is included, the spreading of high energy (E?1?MeV) alpha particles increases slowly with the energy and mode frequency. At lower energies, the redistribution is more sensitive to the mode frequency and particle energy. When a (2, 1) mode is added, the spreading increases significantly and particles can reach the edge of the plasma. Trapped particles are the most affected and the redistribution parameter can have maxima above 1?MeV, depending on the mode frequency. These results can have important implications for ash removal.

  11. 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

  12. 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.

  13. 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

    The original goal of the present thesis was to compare several Solid State Nuclear Track Detectors (SSNTD) as alpha particle detectors. The SSNTD to be compared were different polycarbonates and a cellulose nitrate detector. ...

  14. PPPL-3239 -Preprint: March 1997, UC-420, 427 Calculations of alpha particle loss for reversed magnetic shear

    E-print Network

    magnetic shear in the Tokamak Fusion Test Reactor M. H. Redi, R. B. White, S. H. Batha, F. M. Levinton, D particles in toroidal magnetic PPPL-3239 - Preprint: March 1997, UC-420, 427 Calculations of alpha particle loss for reversed

  15. Study of nuclear recoils in liquid argon with monoenergetic neutrons

    E-print Network

    Regenfus, C; Amsler, C; Creus, W; Ferella, A; Rochet, J; Walter, M

    2012-01-01

    For the development of liquid argon dark matter detectors we assembled a setup in the laboratory to scatter neutrons on a small liquid argon target. The neutrons are produced mono-energetically (E_kin=2.45 MeV) by nuclear fusion in a deuterium plasma and are collimated onto a 3" liquid argon cell operating in single-phase mode (zero electric field). Organic liquid scintillators are used to tag scattered neutrons and to provide a time-of-flight measurement. The setup is designed to study light pulse shapes and scintillation yields from nuclear and electronic recoils as well as from {\\alpha}-particles at working points relevant to dark matter searches. Liquid argon offers the possibility to scrutinise scintillation yields in noble liquids with respect to the populations of the two fundamental excimer states. Here we present experimental methods and first results from recent data towards such studies.

  16. 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.

  17. October 17, 1997 Effects of q(r) on the Alpha Particle Ripple Loss in TFTR

    E-print Network

    to the outer midplane. The alpha particle loss measurements were made using a radially movable scintillator diffusion is fundamentally different from the ripple loss which occurs when an ion is trapped in the low. Although there were several simplifying assumptions used in deriving Eq. 1, a fundamental feature

  18. Photocatalytic water oxidation with suspended alpha-Fe2O3 particles-effects of nanoscaling

    E-print Network

    Osterloh, Frank

    V) for all materials. Cyclic voltammetry gave the water oxidation overpotentials (versus NHE at pH ¼ 7, at 1Photocatalytic water oxidation with suspended alpha-Fe2O3 particles-effects of nanoscaling Troy K on using freely dispersed Fe2O3 nanocrystals for photocatalytic water oxidation. Three morphologies

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

    E-print Network

    Richardson, John

    Differential Flow Between Solar Wind Protons and Alpha J Particles: First WIND Observations . T with bulk - a solar wind flow speed. The detailed WIND measurements en ble us to investigate instances when, it is shown I here to also occur at 1 AU in the ecliptic. ntroduction The solar wind's two primary ion

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

    SciTech Connect

    Espinosa Garcia, Guillermo; Golzarri y Moreno, Dr. Jose Ignacio; Bogard, James S

    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.

  1. Incidence characteristics of alpha particles on detectors irradiated in a radon progeny atmosphere

    E-print Network

    Yu, Peter K.N.

    Incidence characteristics of alpha particles on detectors irradiated in a radon þ progeny: Natural radioactivity; Radon; Detector sensitivity; Monte Carlo methods 1. Introduction It has been established a long time ago that the absorbed radon dose in the human lung is not delivered by radon itself

  2. Nucleon-Alpha Particle Disequilibrium and Short-Lived r-Process Radioactivities

    NASA Technical Reports Server (NTRS)

    Meyer, B. S.; Clayton, D. D.; Chellapilla, S.; The, L.-S.

    2002-01-01

    r-Process yields can be extremely sensitive to expansion parameters when a persistent disequilibrium between free nucleons and alpha particles is present. This may provide a natural scenario for understanding the variation of heavy and light r-process isotopes in different r-process events. Additional information is contained in the original extended abstract.

  3. Can Bose condensation of alpha particles be observed in heavy ion collisions?

    NASA Technical Reports Server (NTRS)

    Tripathi, Ram K.; Townsend, Lawrence W.

    1993-01-01

    Using a fully self-consistent quantum statistical model, we demonstrate the possibility of Bose condensation of alpha particles with a concomitant phase transition in heavy ion collisions. Suggestions for the experimental observation of the signature of the onset of this phenomenon are made.

  4. 1. INTRODUCTION High-energy fusion-product (fp) transport (e.g., alpha particle

    E-print Network

    Hively, Lee M.

    1 1. INTRODUCTION High-energy fusion-product (fp) transport (e.g., alpha particle transport in D-T plasmas) is a central issue in fusion reactor de- velopment. Important effects dependent on fp transport-induced instabilities [2J; the high-energy fp thermali- zation profile and subsequent "ash" build-up [3J; fp bombardment

  5. Fabrication of micropillar substrates using replicas of alpha-particle irradiated and chemically etched PADC films

    E-print Network

    Yu, Peter K.N.

    Fabrication of micropillar substrates using replicas of alpha-particle irradiated and chemically PADC PDMS HeLa cells Cell proliferation a b s t r a c t We proposed a simple method to fabricate. In the micron-scale regime, many micro-fabrication techniques were deployed to create specified surface

  6. A Strange Box and a Stubborn Brit: Rutherford's Experiments with Alpha Particles.

    ERIC Educational Resources Information Center

    Digilov, M.

    1991-01-01

    Discusses 5 innovative experiments conducted by Rutherford in early 1900s utilizing the 30 milligrams of radium salt he personally carried from Europe to Canada in 1903. Traces his work with alpha particles from his original results which determined their nature, charge, and mass, to his technique of backscattering which helped to advance…

  7. Study of Superdeformation in the A {approx_equal} 60 Mass Region; High Resolution {gamma}-Ray Spectroscopy at EUROBALL IV with the Recoil Filter Detector and the EUCLIDES Charged Particle Detector

    SciTech Connect

    Dobaczewski, J.; Vivien, J. P.; Byrski, T.; Curien, D.; Dorvaux, O.; Duchene, G.; Gall, B.; Merdinger, J.C.; Robin, J.; Zuber, K.; Grebosz, J.; Maj, A.; Meczynski, W.; Styczen, J.; Zieblinski, M.; Bednarczyk, P.; De Angelis, G.; Gadea, A.; Farnea, E.; Isocrate, R.

    2004-02-27

    High spin studies of A {approx_equal} 60 nuclei have been carried out with EUROBALL. The nuclei of interest were populated in the fusion-evaporation reaction with a 125 MeV 16O beam bombarding a thin 56Fe target. The use of the Recoil Filter Detector and the charged particle detector EUCLIDES resulted in a significant reduction of {gamma}-line widths and facilitated a reaction channel selection. In this article, several new linking transitions of the previously known terminating band in 64Zn are reported. Such bands are also observed in 61Cu and 63Cu. New SD bands identified in 61,63Cu are discussed.

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

    E-print Network

    Yu, Peter 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 a b s t r a c t Radiation-induced bystander effect refers to the biological response found in cells

  9. 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

  10. 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.

  11. 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

  12. Further measurement of the {beta}-delayed {alpha}-particle emission of {sup 16}N

    SciTech Connect

    France III, R. H.; Wilds, E. L.; McDonald, J. E.; Gai, M.

    2007-06-15

    We measured the {beta}-delayed {alpha}-particle emission spectrum of {sup 16}N with a sensitivity for {beta}-decay branching ratios of the order of 10{sup -10}. The {sup 16}N nuclei were produced using the d({sup 15}N,{sup 16}N)p reaction with 70 MeV {sup 15}N beams and a deuterium gas target 7.5 cm long at a pressure of 1250 torr. The {sup 16}N nuclei were collected (over 10 s) using a thin aluminum foil with an areal density of 180 {mu}g/cm{sup 2} tilted at 7 deg. with respect to the beam. The activity was transferred to the counting area by means of a stepping motor in less than 3 s with the counting carried out over 8 s. The {beta}-delayed {alpha}-particles were measured using a time-of-flight method to achieve a sufficiently low background. Standard calibration sources ({sup 148}Gd, {sup 241}Am, {sup 208,209}Po, and {sup 227}Ac) as well as {alpha} particles and {sup 7}Li from the {sup 10}B(n,{alpha}){sup 7}Li reaction were used for an accurate energy calibration. The energy resolution of the catcher foil (180-220 keV) was calculated and the time-of-flight resolution (3-10 nsec) was measured using the {beta}-delayed {alpha}-particle emission from {sup 8}Li that was produced using the d({sup 7}Li,{sup 8}Li)p reaction with the same setup. The line shape was corrected to account for the variation in the energy and time resolution and a high statistics spectrum of the {beta}-delayed {alpha}-particle emission of {sup 16}N is reported. However, our data (as well as earlier Mainz data and unpublished Seattle data) do not agree with an earlier measurement of the {beta}-delayed {alpha}-particle emission of {sup 16}N taken at TRIUMF after averaging over the energy resolution of our collection system. This disagreement, among other issues, prohibits accurate inclusion of the f-wave component in the R-matrix analysis.

  13. Density-induced suppression of the alpha-particle condensate in nuclear matter and the structure of alpha cluster states in nuclei

    E-print Network

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

    2008-01-21

    At low densities, with decreasing temperatures, in symmetric nuclear matter alpha-particles are formed, which eventually give raise to a quantum condensate with four-nucleon alpha-like correlations (quartetting). Starting with a model of alpha-matter, where undistorted alpha particles interact via an effective interaction such as the Ali-Bodmer potential, the suppression of the condensate fraction at zero temperature with increasing density is considered. Using a Jastrow-Feenberg approach, it is found that the condensate fraction vanishes near saturation density. Additionally, the modification of the internal state of the alpha particle due to medium effects will further reduce the condensate. In finite systems, an enhancement of the S state wave function of the c.o.m. orbital of alpha particle motion is considered as the correspondence to the condensate. Wave functions have been constructed for self-conjugate 4n nuclei which describe the condensate state, but are fully antisymmetrized on the nucleonic level. These condensate-like cluster wave functions have been successfully applied to describe properties of low-density states near the n alpha threshold. Comparison with OCM calculations in 12C and 16O shows strong enhancement of the occupation of the S-state c.o.m. orbital of the alpha-particles. This enhancement is decreasing if the baryon density increases, similar to the density-induced suppression of the condensate fraction in alpha matter. The ground states of 12C and 16O show no enhancement at all, thus a quartetting condensate cannot be formed at saturation densities.

  14. 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.

  15. Many-particle decays of {alpha}-chain structures in {sup 24}Mg

    SciTech Connect

    Wuosmaa, A.H.

    1993-12-31

    We have searched for evidence of exotic cluster configurations in {sup 24}Mg resembling a linear chain of {alpha} particles in various many-particle final states of the {sup 12}C+{sup 12}C system, including {sup 1}C(O{sub 2}{sup +})+{sup 12}C(O{sub 2}{sup +}) and {sup 8}Be+{sup 16}O*(4a). Such configurations are predicted to occur by a number of different theoretical models of the structure of {sup 24}Mg. An array of highly segmented Double-Sided Silicon Strip Detectors permits detailed, high resolution reconstruction of these many-charged-particle final states.

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

    SciTech Connect

    Sasao, Mamiko; Wada, Motoi; Isobe, Mitsutaka

    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.

  17. A spin filter polarimeter and an {alpha}-particle D-state study

    SciTech Connect

    Lemieux, S.K.

    1993-12-31

    A Spin Filter Polarimeter (SFP) which reveals populations of individual hyperfine states of nuclear spin-polarized H{sup {+-}} (or D{sup {+-}}) beams has been tested. the SFP is based on unique properties of a three-level interaction in the 2S{sub 1/2} and 2P{sub 1/2} states of the hydrogen (or deuterium) atoms, created when the polarized ion beams pick up electrons in cesium vapor. The SFP has potential for an absolute accuracy of better than 1.5%, thus it could be used for calibrating polarimeters absolutely for low energy experiments for which no nuclear polarization standard exists. Test results show that the SFP provides a quick and elegant measure of the relative hyperfine state populations in the beam. This {alpha}-particle study is a small part of a larger project studying the deuteron-deuteron configuration of the {alpha}-particle wave function. The differential cross section and tensor analyzing powers (TAP) were measured for the {sup 50}Ti({bar d},{alpha}){sup 48}Sc reaction to the J{sup {pi}} = 7{sup +} state in {sup 48}Sc at E{sub x} = 1.097 MeV and compared with exact finite-range distorted-wave Born approximation (DWBA) calculations. The DWBA calculations use realistic {alpha}-particle wave functions generated from variational Monte-Carlo calculations.

  18. Evidence for alpha-particle chain configurations in {sup 24}Mg

    SciTech Connect

    Wuosmaa, A.H.; Back, B.B.; Betts, R.R.; Ferre, M.; Gehring, J.; Glagola, P.G.; Happ, Th.; Henderson, D.J.; Wilt, P.; Bearden, I.G.

    1992-09-01

    Many theoretical models have been employed to described the structure of the nucleus {sup 24}Mg. Among these are the Cranked Shell model (CSM), the Cranked Cluster Model (CCM), and calculations have also been performed using the Hartree-Fock formalism. One very striking prediction of these calculations is that in this nucleus there exist very unusual configurations, with structures reminiscent of linear chains of alpha particles. In the CSM, for instance, such a configuration is identified with a pronounced minimum in the potential energy energy at very large prolate deformation. In the CCM, several very different alpha-particle duster configurations are identified, many having rather large deformations. These cluster configurations can be associated with the different potential-energy minima obtained in the CSM results. In the case of the CCM, a 6{alpha} chain-like configuration is predicted to occur at excitation energies between 40 and 50 MeV, with predicted rotational spacing given by {Dirac_h}{sup 2}/2I=22 keV. At this excitation energy, such a chain configuration would lie well above the threshold for the decay of {sup 24}Mg into 6 alpha particles, and its identification poses a difficult experimental challenge. This report discusses this challenge.

  19. Evidence for alpha-particle chain configurations in sup 24 Mg

    SciTech Connect

    Wuosmaa, A.H.; Back, B.B.; Betts, R.R.; Ferre, M.; Gehring, J.; Glagola, P.G.; Happ, Th.; Henderson, D.J.; Wilt, P. ); Bearden, I.G. . Dept. of Physics)

    1992-01-01

    Many theoretical models have been employed to described the structure of the nucleus {sup 24}Mg. Among these are the Cranked Shell model (CSM), the Cranked Cluster Model (CCM), and calculations have also been performed using the Hartree-Fock formalism. One very striking prediction of these calculations is that in this nucleus there exist very unusual configurations, with structures reminiscent of linear chains of alpha particles. In the CSM, for instance, such a configuration is identified with a pronounced minimum in the potential energy energy at very large prolate deformation. In the CCM, several very different alpha-particle duster configurations are identified, many having rather large deformations. These cluster configurations can be associated with the different potential-energy minima obtained in the CSM results. In the case of the CCM, a 6{alpha} chain-like configuration is predicted to occur at excitation energies between 40 and 50 MeV, with predicted rotational spacing given by {Dirac h}{sup 2}/2I=22 keV. At this excitation energy, such a chain configuration would lie well above the threshold for the decay of {sup 24}Mg into 6 alpha particles, and its identification poses a difficult experimental challenge. This report discusses this challenge.

  20. 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

  1. 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

  2. Alpha-Particle Angular Distributions of At and Rn Isotopes and Their Relation to Nuclear Structure

    SciTech Connect

    NICOLE Collaboration and ISOLDE Collaboration

    1996-12-01

    We report on an extensive on-line nuclear orientation study of the angular distribution of {alpha} particles emitted in the favored decay of neutron deficient At and Rn nuclei near the {ital N}=126 shell closure. Surprisingly large anisotropies were observed, showing pronounced changes from one isotope to another. Comparing these data with several theoretical models shows that anisotropic {alpha} emission in favored decays from near-spherical nuclei can well be explained within the shell model, implying that it is mainly determined by the structure of the decaying nucleus. {copyright} {ital 1996 The American Physical Society.}

  3. Effect of Alpha-Particle Irradiation on Brain Glycogen in the Rat

    NASA Technical Reports Server (NTRS)

    Wolfe, L. S.; Klatzo, Igor; Miquel, Jaime; Tobias, Cornelius; Haymaker, Webb

    1962-01-01

    The studies of Klatzo, Miquel, Tobias and Haymaker (1961) have shown that one of the earliest and most sensitive indications of the effects of alpha-particle irradiation on rat bran is the appearance of glycogen granules mainly in the neuroglia of the exposed area of the brain. Periodic acid-Schiff (PAS) positive, alpha-amylase soluble granules were demonstrated within 12 hr after irradiation, preceding by approximately 36 hr the first microscopically detectable vascular permeability disturbances, as shown by the fluorescein labeled serum protein technique. These studies suggested that the injurious effects of alpha-particle energy were on cellular elements primarily, according to the physical properties and distribution of the radiation in the tissue, and that the vascular permeability disturbances played a secondary role in pathogenesis. The purpose of this study was to correlate the histochemical observations on glycogen with a quantitative assessment of the glycogen in the irradiated brain tissue. It is felt that such a study may contribute to the understanding of radiation injury at the molecular level. A practical aspect of this problem is that the information on biological radiation effects due to accelerated particles from the cyclotron source, is employed in this study, is applicable to radiation from cosmic particles both in free space and entrapped in the Van Allen belts.

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

    E-print Network

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

    2013-05-21

    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.

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

    SciTech Connect

    Rabin, Michael W; Hoover, Andrew S; Bacrania, Mnesh K; Croce, Mark P; Hoteling, N J; Lamont, S P; Plionis, A A; Dry, D E; Ullom, J N; Bennett, D A; Horansky, R; Kotsubo, V; Cantor, R

    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.

  6. New measurements of W-values for protons and alpha particles.

    PubMed

    Giesen, U; Beck, J

    2014-10-01

    The increasing importance of ion beams in cancer therapy and the lack of experimental data for W-values for protons and heavy ions in air require new measurements. A new experimental set-up was developed at PTB and consistent measurements of W-values in argon, nitrogen and air for protons and alpha particles with energies from 0.7 to 3.5 MeV u(-1) at PTB, and for carbon ions between 3.6 and 7.0 MeV u(-1) at GSI were carried out. This publication concentrates on the measurements with protons and alpha particles at PTB. The experimental methods and the determination of corrections for recombination effects, beam-induced background radiation and additional effects are presented. PMID:24262925

  7. Development of scintillator plates with high energy resolution for alpha particles made of GPS scintillator grains

    NASA Astrophysics Data System (ADS)

    Shimaoka, Takehiro; Kaneko, Junichi H.; Izaki, Kenji; Tsubota, Youichi; Higuchi, Mikio; Nishiyama, Shusuke

    2014-01-01

    A scintillator plate with high energy resolution was developed to produce an alpha particle monitor used in nuclear fuel reprocessing plants and mixed plutonium-uranium oxide (MOX) fuel plants. Grains of a Gd2Si2O7 (GPS) scintillator of several 10 to 550 ?m were fixed on a glass substrate and were then mechanically polished. By increasing the size of scintillator grains and removing fine powders, the collected light yield and energy resolution for alpha particles were drastically improved. Energy resolution of 9.3% was achieved using average grain size of 91 ?m. Furthermore, the ratios between counts in a peak and total counts were improved by more than 60% by the further increase of grain size and adoption of mechanically polished surfaces on both sides. Beta and gamma ray influences were suppressed sufficiently by the thin 100 ?m scintillator plates.

  8. 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.

    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.

  9. Collisional stochastic ripple diffusion of alpha particles and beam ions on TFTR

    SciTech Connect

    Redi, M.H.; Zarnstorff, M.C,; White, R.B.; Budny, R.V.; Schivell, J.F.; Scott, S.D.; Zweben, S.J.

    1994-09-01

    Predictions for ripple loss of fast ions from TFTR are investigated with a guiding center including both collisional and ripple effects. Discrepancies between measurements and calculations of plasma beta at low current and large major radius are resolved when both effects are included for neutral beam ions. A synergistic enhancement of fast ion diffusion is found for toroidal field ripple with collisions. S = 5.4 for neutral beam ions and S = 1.4--2.4 for alpha particles. A 20--30% reduction in alpha particle heating is predicted for R = 2.6 m DT plasmas on TFTR due to first orbit and collisional stochastic ripple diffusion, although these losses will be reduced if q{sub a} and R are smaller, as for most planned DT experiments.

  10. 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.

  11. 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

  12. Nanodosimetry and nanodosimetric-based models of radiation action for radon alpha particles

    SciTech Connect

    Zaider, M.

    1992-01-01

    We report on a theory for describing the biological effects of ionizing radiation in particular radon [alpha] particles. Behind this approach is the recognition that biological effects such as chromosome aberrations, cellular transformation, cellular inactivation, etc, are the result of a hierarchic sequence of radiation effects. We indicate how to treat each of the individual processes in this sequence, and also how to relate one effect to the hierarchically superior one.

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

    SciTech Connect

    Bunno, M.; Nakamura, Y.; Suzuki, Y.; Shinohara, K.; Matsunaga, G.; Tani, K.

    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.

  14. The local skin dose conversion coefficients of electrons, protons and alpha particles calculated using the Geant4 code.

    PubMed

    Zhang, Bintuan; Dang, Bingrong; Wang, Zhuanzi; Wei, Wei; Li, Wenjian

    2013-10-01

    The skin tissue-equivalent slab reported in the International Commission on Radiological Protection (ICRP) Publication 116 to calculate the localised skin dose conversion coefficients (LSDCCs) was adopted into the Monte Carlo transport code Geant4. The Geant4 code was then utilised for computation of LSDCCs due to a circular parallel beam of monoenergetic electrons, protons and alpha particles <10 MeV. The computed LSDCCs for both electrons and alpha particles are found to be in good agreement with the results using the MCNPX code of ICRP 116 data. The present work thus validates the LSDCC values for both electrons and alpha particles using the Geant4 code. PMID:23610196

  15. Critical temperature for {alpha}-particle condensation within a momentum-projected mean-field approach

    SciTech Connect

    Sogo, T.; Roepke, G.; Lazauskas, R.

    2009-05-15

    {alpha}-particle (quartet) condensation in homogeneous spin-isospin symmetric nuclear matter is investigated. The usual Thouless criterion for the critical temperature is extended to the quartet case. The in-medium four-body problem is strongly simplified by the use of a momentum-projected mean-field ansatz for the quartet. The self-consistent single-particle wave functions are shown and discussed for various values of the density at the critical temperature. Excellent agreement of the critical temperature with a numerical solution of the Faddeev-Yakubovsky equation is obtained.

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

    SciTech Connect

    Gomberoff, L.; Gomberoff, K.; Deutsch, A.

    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.

  17. Radioluminescence of solid neodymium-doped laser materials excited by {alpha}-particles and fission fragments

    SciTech Connect

    Seregina, E A; Seregin, A A

    2013-02-28

    The characteristics of radioluminescence of Nd{sup 3+} : Y{sub 3}Al{sub 5}O{sub 12} crystals and laser glasses under excitation by plutonium-239 ({sup 239}Pu) {alpha}-particles, as well as by {alpha}-particles and spontaneous fission fragments of californium-252 ({sup 252}Cf), are studied. The radioluminescence branching ratios {beta}{sub ij} for the transition from the {sup 2}F2{sub 5/2} level to the {sup 2S+1}L{sub J} levels in Nd{sup 3+} : Y{sub 3}Al{sub 5}O{sub 12} crystals are measured. Radioluminescence from the {sup 2}P{sub 3/2} level to low-lying levels is observed. The {beta}{sub ij} ratios for transitions from the high-lying {sup 2}F2{sub 5/2}, {sup 4}D{sub 3/2}, and {sup 2}P{sub 3/2} levels are theoretically calculated. The lifetimes of metastable levels of Nd{sup 3+} excited by {sup 252}Cf fission fragments are measured. The efficiency of the conversion of energy of {alpha}-particles and fission fragments to the energy of optical radiation of Nd{sup 3+} : Y{sub 3}Al{sub 5}O{sub 12} crystals and laser glasses is determined. (active media)

  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. 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.

  20. 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.

  1. 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.

  2. Electron Microscopy Study of Stainless Steel Radiation Damage Due to Long-Term Irradation by Alpha Particles Emitted From Plutonium

    SciTech Connect

    Unlu, Kenan; Rios-Martinez, Carlos; Saglam, Mehmet; Hart, Ron R.; Shipp, John D.; Rennie, John

    1998-04-16

    Radiation damage and associated surface and microstructural changes produced in stainless steel encapsulation by high-fluence alpha particle irradiations from weapons-grade plutonium of 316-stainless steel are being investigated.

  3. CHARGE-EXCHANGE LIMITS ON LOW-ENERGY {alpha}-PARTICLE FLUXES IN SOLAR FLARES

    SciTech Connect

    Hudson, H. S.; Fletcher, L.; MacKinnon, A. L.; Woods, T. N.

    2012-06-20

    This paper reports on a search for flare emission via charge-exchange radiation in the wings of the Ly{alpha} line of He II at 304 A, as originally suggested for hydrogen by Orrall and Zirker. Via this mechanism a primary {alpha} particle that penetrates into the neutral chromosphere can pick up an atomic electron and emit in the He II bound-bound spectrum before it stops. The Extreme-ultraviolet Variability Experiment on board the Solar Dynamics Observatory gives us our first chance to search for this effect systematically. The Orrall-Zirker mechanism has great importance for flare physics because of the essential roles that particle acceleration plays; this mechanism is one of the few proposed that would allow remote sensing of primary accelerated particles below a few MeV nucleon{sup -1}. We study 10 events in total, including the {gamma}-ray events SOL2010-06-12 (M2.0) and SOL2011-02-24 (M3.5) (the latter a limb flare), seven X-class flares, and one prominent M-class event that produced solar energetic particles. The absence of charge-exchange line wings may point to a need for more complete theoretical work. Some of the events do have broadband signatures, which could correspond to continua from other origins, but these do not have the spectral signatures expected from the Orrall-Zirker mechanism.

  4. Interaction of alpha particle beams with Fe-based and FeNi-based glassy ferromagnets

    SciTech Connect

    Sorescu, M.; Barb, D.

    1996-12-31

    Samples of Fe{sub 78}B{sub 13}Si{sub 9} and Fe{sub 40}Ni{sub 38}Mo{sub 4}B{sub 18} 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 texture and phase composition of alloy samples were studied by Moessbauer spectroscopy. Related morphological changes and resultant crystalline precipitates were characterized by scanning electron microscopy. 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. The lowest radiation dose employed was found to be more effective in inducing amorphous-to-crystalline transformations in both ferromagnetic alloys studied. In addition, the FeNi-based amorphous system investigated was found to be more stale than the Fe-based metallic glass, exposed to the same particle-beam irradiation conditions. By stimulating unconventional pathways for the crystallization process, the interaction of alpha particle beams with glassy ferromagnets offers unique opportunities to understand the fundamentals of nucleation and growth in amorphous magnets.

  5. Identification of gene-based responses in human blood cells exposed to alpha particle radiation

    PubMed Central

    2014-01-01

    Background The threat of a terrorist-precipitated nuclear event places humans at danger for radiological exposures. Isotopes which emit alpha (?)-particle radiation pose the highest risk. Currently, gene expression signatures are being developed for radiation biodosimetry and triage with respect to ionizing photon radiation. This study was designed to determine if similar gene expression profiles are obtained after exposures involving ?-particles. Methods Peripheral blood mononuclear cells (PBMCs) were used to identify sensitive and robust gene-based biomarkers of ?-particle radiation exposure. Cells were isolated from healthy individuals and were irradiated at doses ranging from 0-1.5 Gy. Microarray technology was employed to identify transcripts that were differentially expressed relative to unirradiated cells 24 hours post-exposure. Statistical analysis identified modulated genes at each of the individual doses. Results Twenty-nine genes were common to all doses with expression levels ranging from 2-10 fold relative to control treatment group. This subset of genes was further assessed in independent complete white blood cell (WBC) populations exposed to either ?-particles or X-rays using quantitative real-time PCR. This 29 gene panel was responsive in the ?-particle exposed WBCs and was shown to exhibit differential fold-changes compared to X-irradiated cells, though no ?-particle specific transcripts were identified. Conclusion Current gene panels for photon radiation may also be applicable for use in ?-particle radiation biodosimetry. PMID:25017500

  6. A new mechanism for DNA alterations induced by alpha particles such as those emitted by radon and radon progeny.

    PubMed Central

    Lehnert, B E; Goodwin, E H

    1997-01-01

    The mechanism(s) by which alpha (alpha) particles like those emitted from inhaled radon and radon progeny cause their carcinogenic effects in the lung remains unclear. Although direct nuclear traversals by alpha-particles may be involved in mediating these outcomes, increasing evidence indicates that a particles can cause alterations in DNA in the absence of direct hits to cell nuclei. Using the occurrence of excessive sister chromatid exchanges (SCE) as an index of DNA damage in human lung fibroblasts, we investigated the hypothesis that alpha-particles may induce DNA damage through the generation of extracellular factors. We have found that a relatively low dose of alpha-particles can result in the generation of extracellular factors, which, upon transfer to unexposed normal human cells, can cause excessive SCE to an extent equivalent to that observed when the cells are directly irradiated with the same irradiation dose. A short-lived, SCE-inducing factor(s) is generated in alpha-irradiated culture medium containing serum in the absence of cells. A more persistent SCE-inducing factor(s), which can survive freeze-thaw and is heat labile is produced by fibroblasts after exposure to the alpha-particles. These results indicate that the initiating target for alpha-particle-induced genetic changes can be larger than a cell's nucleus or even a whole cell. How transmissible factors like those observed here in vitro may extend to the in vivo condition in the context of a-particle-induced carcinogenesis in the respiratory tract remains to be determined. PMID:9400706

  7. Discrimination between Nuclear Recoils and Electron Recoils by Simultaneous Detection of Phonons and Scintillation Light

    E-print Network

    P. Meunier; M. Bravin; M. Bruckmayer; S. Giordano; M. Loidl; O. Meier; F. Proebst; W. Seidel; M. Sisti; L. Stodolsky; S. Uchaikin; L. Zerle

    1999-06-08

    We have developed a detector, consisting of a cryogenic calorimeter with a scintillating crystal as absorber, and a second calorimeter for the detection of the scintillation light, both operated at 12 mK. Using a CaWO4 crystal with a mass of 6g as scintillating absorber, we have achieved a discrimination of nuclear recoils against electron recoils with a suppression factor of 99.7% at energies above 15 keV. This novel method will be applied for background rejection in the CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) experiment looking for dark matter Weakly Interacting Massive Particles (WIMPs).

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

    NASA Astrophysics Data System (ADS)

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

    2003-11-01

    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 materials at the MER landing sites. The sensor head has simply to be docked by the IDD on the surface of the selected sample. X-ray radiation, excited by alpha particles and X rays of the radioactive sources, is recorded by a high-resolution X-ray detector. The X-ray spectra show elements starting from sodium up to yttrium, depending on their concentrations. The backscattered alpha spectra, measured by a ring of detectors, provide additional data on carbon and oxygen. By means of a proper calibration, the elemental concentrations are derived. Together with data from the two other Athena instruments mounted on the IDD, the samples under investigation can be fully characterized. Key APXS objectives are the determination of the chemistry of crustal rocks and soils and the examination of water-related deposits, sediments, or evaporates. Using the rock abrasion tool attached to the IDD, issues of weathering can be addressed by measuring natural and abraded surfaces of rocks.

  9. Induction of a bystander mutagenic effect of alpha particles in mammalian cells

    NASA Technical Reports Server (NTRS)

    Zhou, H.; Randers-Pehrson, G.; Waldren, C. A.; Vannais, D.; Hall, E. J.; Hei, T. K.; Chatterjee, A. (Principal Investigator)

    2000-01-01

    Ever since the discovery of X-rays was made by Rontgen more than a hundred years ago, it has always been accepted that the deleterious effects of ionizing radiation such as mutation and carcinogenesis are attributable mainly to direct damage to DNA. Although evidence based on microdosimetric estimation in support of a bystander effect appears to be consistent, direct proof of such extranuclear/extracellular effects are limited. Using a precision charged particle microbeam, we show here that irradiation of 20% of randomly selected A(L) cells with 20 alpha particles each results in a mutant fraction that is 3-fold higher than expected, assuming no bystander modulation effect. Furthermore, analysis by multiplex PCR shows that the types of mutants induced are significantly different from those of spontaneous origin. Pretreatment of cells with the radical scavenger DMSO had no effect on the mutagenic incidence. In contrast, cells pretreated with a 40 microM dose of lindane, which inhibits cell-cell communication, significantly decreased the mutant yield. The doses of DMSO and lindane used in these experiments are nontoxic and nonmutagenic. We further examined the mutagenic yield when 5-10% of randomly selected cells were irradiated with 20 alpha particles each. Results showed, likewise, a higher mutant yield than expected assuming no bystander effects. Our studies provide clear evidence that irradiated cells can induce a bystander mutagenic response in neighboring cells not directly traversed by alpha particles and that cell-cell communication process play a critical role in mediating the bystander phenomenon.

  10. Cavity cooling below the recoil limit.

    PubMed

    Wolke, Matthias; Klinner, Julian; Keßler, Hans; Hemmerich, Andreas

    2012-07-01

    Conventional laser cooling relies on repeated electronic excitations by near-resonant light, which constrains its area of application to a selected number of atomic species prepared at moderate particle densities. Optical cavities with sufficiently large Purcell factors allow for laser cooling schemes, avoiding these limitations. Here, we report on an atom-cavity system, combining a Purcell factor above 40 with a cavity bandwidth below the recoil frequency associated with the kinetic energy transfer in a single photon scattering event. This lets us access a yet-unexplored regime of atom-cavity interactions, in which the atomic motion can be manipulated by targeted dissipation with sub-recoil resolution. We demonstrate cavity-induced heating of a Bose-Einstein condensate and subsequent cooling at particle densities and temperatures incompatible with conventional laser cooling. PMID:22767925

  11. 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.

  12. Energy distribution of ternary {alpha} particles in spontaneous fission of {sup 252}Cf

    SciTech Connect

    Mutterer, M.; Kalben, J. von; Kopatch, Yu. N.; Yamaledtinov, S. R.; Lyapin, V. G.; Sillanpaeae, M.; Trzaska, W. H.; Khlebnikov, S. V.; Tyurin, G. P.

    2008-12-15

    The energy distribution of the ternary {alpha} particles in spontaneous fission of {sup 252}Cf was measured. For the first time an energy threshold as low as 1 MeV was reached. The experiment used an array of unshielded silicon detectors measuring energy and time-of-flight (TOF) of ternary particles in coincidence with fission fragments. The TOF resolution of the system was sufficient for clear separation of {sup 6}He and tritons from {sup 4}He. The statistics were adequate to extract the {sup 6}He/{sup 4}He yield ratio. For both {sup 4}He and {sup 6}He, an excess in the yield (as compared to a Gaussian shape) was observed at energies below 9 MeV. The measured ternary {alpha} spectrum was corrected for the distortion induced by the detection geometry covering equatorial particle emission only. The emission angle was found to affect mainly the width of the energy distribution by up to 1 MeV.

  13. Proton and alpha particle precipitation onto the upper atmosphere of Venus

    NASA Astrophysics Data System (ADS)

    Stenberg Wieser, G.; Ashfaque, M.; Nilsson, H.; Futaana, Y.; Barabash, S.; Diéval, C.; Fedorov, A.; Zhang, T. L.

    2015-08-01

    We study the precipitation of protons and alpha-particles onto the upper atmosphere of Venus, using particle data recorded by the Venus Express spacecraft inside the induced magnetosphere. Our investigations are limited to the dayside close to the terminator. We observe on average a net downward flux of protons, which originate partly from the planetary atmosphere and partly from the solar wind. We present median energy spectra of the precipitating protons divided into two energy ranges, 10-100 eV and 100 eV-30 keV. The total dayside precipitation of solar wind protons is estimated to be 3×1022 s-1, assuming only protons with energies above 500 eV will reach the exobase. Downgoing protons are frequently observed but only in 3% of the available data records we see He2+. These observations are made close to the induced magnetosphere boundary and we argue that at lower altitude the countrates for alpha-particles fall below detection limits. We estimate the precipitation of He2+ onto the dayside exobase to be 1×1021 s-1, which is not enough enough to replace the helium escaping from the planet.

  14. Secondary ion mass spectrometry combined with alpha track detection for isotope abundance ratio analysis of individual uranium-bearing particles.

    PubMed

    Esaka, Fumitaka; Magara, Masaaki

    2014-03-01

    Secondary ion mass spectrometry (SIMS) was used in combination with alpha track detection for the efficient analysis of uranium-bearing particles with higher (235)U abundances in environmental samples. A polycarbonate film containing particles was prepared and placed in contact with a CR-39 plastic detector. After exposure for 28 days, the detector was etched in a NaOH solution and each uranium-bearing particle was identified through observation of the alpha tracks recorded in the detector. A portion of the film containing each uranium-bearing particle was cut out and put onto a glassy carbon planchet. The films on the planchet were decomposed through plasma ashing for subsequent uranium abundance ratio analysis with SIMS. The alpha track-SIMS analysis of 10 uranium-bearing particles in a sample taken from a nuclear facility enabled n((235)U)/n((238)U) abundance ratios in the range 0.0072-0.25 to be detected, which were significantly higher than those obtained by SIMS without alpha track detection. The duration of the whole analytical process for analysis of 10 particles was about 32 days. The detection efficiency was calculated to be 27.1±6.5%, based on the analysis of the particles in uranium reference materials. The detection limits, defined as the diameter of the particle which produces alpha tracks more than one for a 28-days exposure, were estimated to be 0.8, 0.9, 1.1, 2.1 and 3.0 ?m for the particles having the same uranium abundance ratios with NBL CRM U850, U500, U350, U050 and U010 reference materials, respectively. The use of alpha track detection for subsequent SIMS analysis is an inexpensive and an efficient way to measure uranium-bearing particles with higher (235)U abundances. PMID:24468381

  15. Differential Velocity between Solar Wind Protons and Alpha Particles in Pressure Balance Structures

    NASA Technical Reports Server (NTRS)

    Yamauchi, Yohei; Suess, Steven T.; Steinberg, John T.; Sakurai, Takashi

    2004-01-01

    Pressure balance structures (PBSs) are a common high-plasma beta feature in high-latitude, high-speed solar wind. They have been proposed as remnants of coronal plumes. If true, they should reflect the observation that plumes are rooted in unipolar magnetic flux concentrations in the photosphere and are heated as oppositely directed flux is advected into and reconnects with the flux concentration. A minimum variance analysis (MVA) of magnetic discontinuities in PBSs showed there is a larger proportion of tangential discontinuities than in the surrounding high-speed wind, supporting the hypothesis that plasmoids or extended current sheets are formed during reconnection at the base of plumes. To further evaluate the character of magnetic field discontinuities in PBSs, differential streaming between alpha particles and protons is analyzed here for the same sample of PBSs used in the MVA. Alpha particles in high-speed wind generally have a higher radial flow speed than protons. However, if the magnetic field is folded back on itself, as in a large-amplitude Alfven wave, alpha particles will locally have a radial flow speed less than protons. This characteristic is used here to distinguish between folded back magnetic fields (which would contain rotational discontinuities) and tangential discontinuities using Ulysses high-latitude, high-speed solar wind data. The analysis indicates that almost all reversals in the radial magnetic field in PBSs are folded back field lines. This is found to also be true outside PBSs, supporting existing results for typical high-speed, high-latitude wind. There remains a small number of cases that appear not to be folds in the magnetic field and which may be flux tubes with both ends rooted in the Sun. The distinct difference in MVA results inside and outside PBSs remains unexplained.

  16. Differential Velocity Between Solar Wind Protons and Alpha Particles in Pressure Balance Structures

    NASA Technical Reports Server (NTRS)

    Yamauchi, Y.; Suess, S. T.; Steinberg, J. T.; Sakurai, T.

    2003-01-01

    Pressure balance structures (PBSs) are a common high plasma beta feature in high latitude, high speed solar wind. They have been proposed as remnants of coronal plumes. If true, they should reflect the observation that plumes are rooted in unipolar magnetic flux concentrations in the photosphere and are heated as oppositely directed flux is advected into and reconnects with the flux concentration. A minimum variance analysis (MVA) of magnetic discontinuities in PBSs showed there is a larger proportion of tangential discontinuities than in the surrounding high speed wind, supporting the hypothesis that plasmoids or extended current sheets are formed during reconnection at the base of plumes. To further evaluate the character of magnetic field discontinuities in PBSs, differential streaming between alpha particles and protons is analyzed here for the same sample of PBSs used in the MVA. Alpha particles in high speed wind generally have a higher radial flow speed than protons. However, if the magnetic field is folded back on itself, as in a large amplitude Alfven wave, alpha particles will locally have a radial flow speed less than protons. This characteristic is used here to distinguish between folded back magnetic fields (which would contain rotational discontinuities) and tangential discontinuities using Ulysses high latitude, high speed solar wind data. The analysis indicates that almost all reversals in the radial magnetic field in PBSs are folded back field lines. This is found to also be true outside PBSs, supporting existing results for typical high speed, high latitude wind. There remains a small number of cases that appear not to be folds in the magnetic field and which may be flux tubes with both ends rooted in the Sun. The distinct difference in MVA results inside and outside PBSs remains unexplained.

  17. Elastic scattering of alpha particles and the phase of the nucleon-nucleon scattering amplitude

    NASA Technical Reports Server (NTRS)

    Franco, V.; Yin, Y.

    1985-01-01

    Glauber theory can describe elastic scattering of alpha particles by He-4, He-3, H-2, and H-1 at 7 GeV/c if the phase of the nucleon-nucleon elastic-scattering amplitude varies with momentum transfer. The phase variation leads to diffraction patterns differing markedly from those typical of constant-phase calculations and greatly affects the magnitudes of the intensities. These changes are mainly due to changes in the interference between amplitudes for different orders of multiple scattering and to a decrease in their moduli.

  18. Model of alpha particle diffusion in the outer limiter shadow of TFTR

    SciTech Connect

    Wang, S. |; Zweben, S.J.

    1996-05-01

    A new code, Monte Carlo Collisional Stochastic Orbit Retracing (MCCSOR), has been developed to model the alpha particle loss signal as measured by the outer midplane scintillator detector in TFTR. The shadowing effects due to the outer limiters and the detector itself have been included, along with a pitch angle scattering and stochastic ripple diffusion. Shadowing by the outer limiters has a strong effect on both the magnitude and pitch angle distribution of the calculated loss. There is at least qualitative agreement between the calculated results and the experimental data.

  19. Generation of volatile organic compounds by alpha particle degradation of WIPP plastic and rubber material

    SciTech Connect

    Reed, D.T.; Molecke, M.A.

    1993-12-31

    The generation of volatile organic compounds (VOCs), hydrogen, and carbon oxides due to alpha particle irradiation of polyethylene, polyvinylchloride, hypalon, and neoprene, is being investigated. A wide diversity of VOCs was found including alkenes, alkanes, alcohols, ketones, benzene derivatives, and nitro compounds. Their yields however, were quite low. The relative amounts of these compounds depended on the material, atmosphere present, and the absorbed dose. This investigation will help evaluate the effect of ionizing radiation on the long-term performance assessment and regulatory compliance issues related to the Waste Isolation Pilot Plant (WIPP).

  20. 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.

  1. Evidence for strong refraction of $^3$He in an alpha-particle condensate

    E-print Network

    S. Ohkubo; Y. Hirabayashi

    2011-02-09

    We have analyzed $^{3}$He scattering from $^{12}$C at 34.7 and 72 MeV in a coupled channel method with a double folding potential derived from the precise wave functions for the ground 0$^+$ state and $0_2^+$ (7.65 MeV) Hoyle state, which has been suggested to be an $\\alpha$ particle condensate. It is found that strong refraction of $^3$He in the Hoyle state can be clearly seen in the experimental angular distribution at {\\it low} incident energy region as an Airy minimum of the {\\it pre-rainbow oscillations}.

  2. Anomalous effect of trench-oxide depth on alpha-particle-induced charge collection

    SciTech Connect

    Shin, H.; Kim, N.M.

    1999-06-01

    The effect of trench-oxide depth on the alpha-particle-induced charge collection is analyzed for the first time. From the simulation results, it was found that the depth of trench oxide has a considerable influence on the amount of collected charge. The confining of generated charge by the trench oxide was identified as a cause of this anomalous effect. Therefore, the tradeoff between soft error rate and cell to cell isolation characteristics should be considered in optimizing the depth of trench oxide.

  3. 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.

  4. THE ROLE OF ALPHA PARTICLES IN THE EVOLUTION OF THE SOLAR-WIND TURBULENCE TOWARD SHORT SPATIAL SCALES

    SciTech Connect

    Perrone, D.; Valentini, F.; Veltri, P.

    2011-11-01

    We present a numerical study of the kinetic dynamics of protons and alpha particles during the evolution of the solar-wind turbulent cascade, in which the energy injected in large-scale slab-type Alfvenic fluctuations is transferred toward short spatial scale lengths, across the proton skin depth. We make use of a hybrid Vlasov-Maxwell code that integrates numerically the Vlasov equation for both the ion species, while the electrons are considered as a fluid. The system evolution is investigated in terms of different values of the electron to proton and alpha particle to proton temperature ratios. The numerical results show that the previously studied kinetic dynamics of protons is not strongly affected by the presence of alpha particles, at least when they are present in low concentration. Our simulations not only provide a physical explanation for the generation of beams of accelerated particles along the direction of the ambient magnetic field for both protons and alpha particles, but also show that this mechanism is more efficient for protons than for alpha particles, in agreement with recent solar-wind data analyses.

  5. The fine structure constant alpha: relevant for a model of a self-propelling photon and for particle masses

    NASA Astrophysics Data System (ADS)

    Greulich, Karl O.

    2015-09-01

    A model for a self propelling (i.e. massless) photon1 is based on oscillations of a pair of charges amounting to elementary charge divided by SQRT alpha, where alpha is the fine structure (Sommerfeld) constant. When one assumes a similar model for particles that do have rest mas (i.e. which are non- self propelling), alpha plays also a role in the rest masses of elementary particles. Indeed all fundamental elementary particle masses can be described by the alpha / beta rule2 --> m(particle) = alpha-n * betam* 27.2 eV /c2 where beta is the proton to electron mass ratio 183612 and n= 0….14, m= -1,0 or Thus, photons and particle masses are intimately related to the fine structure constant. If the latter would not have been strictly constant throughout all times, this would have had consequences for the nature of light and for all masses including those of elementary particles.

  6. 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.

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

    SciTech Connect

    Sorescu, M.; Barb, D.

    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.

  8. Realistic Ghost State : Pauli Forbidden State from Rigorous Solution of the Alpha Particle

    E-print Network

    H. Kamada; S. Oryu; A. Nogga

    2000-05-06

    The antisymmetrization of the composite particles in cluster model calculations manifests itself in Pauli forbidden states (ghost states), if one restricts oneself on undeformed cluster in the low energy region. The resonating group method and the generating coordinate method rely on a property of the norm kernel, which introduces some of the ghost states. The norm kernel has been usually calculated under the assumption that the inner wavefunctions have a simple Gaussian form. It is the first time that this assumption is tested by the rigorous way. In the 4He+N system, we demonstrate a ghost state, which is calculated from a rigorous solution of Yakubovsky equations for the alpha particle. The ghost states calculated by rigorous and approximate methods turn out to have a very similar form. It is analytically proved that the trace of the norm kernel does not depend on the inner wavefunction we choose.

  9. Measurement of ion cascade energies through resolution degradation of alpha particle microcalorimeters

    SciTech Connect

    Horansky, Robert D.; Stiehl, Gregory M.; Beall, James A.; Irwin, Kent D.; Ullom, Joel N.; Plionis, Alexander A.; Rabin, Michael W.

    2010-02-15

    Atomic cascades caused by ions impinging on bulk materials have remained of interest to the scientific community since their discovery by Goldstein in 1902. While considerable effort has been spent describing and, more recently, simulating these cascades, tools that can study individual events are lacking and several aspects of cascade behavior remain poorly known. These aspects include the material energies that determine cascade magnitude and the variation between cascades produced by monoenergetic ions. We have recently developed an alpha particle detector with a thermodynamic resolution near 100 eV full-width-at-half-maximum (FWHM) and an achieved resolution of 1.06 keV FWHM for 5.3 MeV particles. The detector relies on the absorption of particles by a bulk material and a thermal change in a superconducting thermometer. The achieved resolution of this detector provides the highest resolving power of any energy dispersive technique and a factor of 8 improvement over semiconductor detectors. The exquisite resolution can be directly applied to improved measurements of fundamental nuclear decays and nuclear forensics. In addition, we propose that the discrepancy between the thermodynamic and achieved resolution is due to fluctuations in lattice damage caused by ion-induced cascades in the absorber. Hence, this new detector is capable of measuring the kinetic energy converted to lattice damage in individual atomic cascades. This capability allows new measurements of cascade dynamics; for example, we find that the ubiquitous modeling program, SRIM, significantly underestimates the lattice damage caused in bulk tin by 5.3 MeV alpha particles.

  10. 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

  11. An improved electrostatic integrating radon monitor with the CR-39 as alpha-particle detector.

    PubMed

    Fan, D; Zhuo, W; Chen, B; Zhao, C; Yi, Y; Zhang, Y

    2015-11-01

    In this study, based on the electrostatic integrating radon monitor (EIRM) developed by Iida et al., a new type of EIRM with the allyl glycol carbonate (CR-39) as alpha-particle detector was developed for outdoor radon measurements. Besides using the CR-39 to replace the cellulose nitrate film as alpha-particle detector, the electrode and the setting place of the CR-39 were also optimally designed based on the simulation results of the electric field and the detection efficiency. The calibration factor of the new EIRM was estimated to be 0.136±0.002 tracks cm(-2) (Bq m(-3) h)(-1), with the lower detection limit of 0.6 Bq m(-3) for a 2-month exposure. Furthermore, both the battery and the dry agent were also replaced to protect the environment. The results of intercomparison and field experiments showed that the performances of the new EIRM were much better than the original one. It suggests that the new type of ERIM is more suitable for large-scale and long-term outdoor radon surveys. PMID:25920784

  12. Detailed 8-transistor SRAM cell analysis for improved alpha particle radiation hardening in nanometer technologies

    NASA Astrophysics Data System (ADS)

    Bota, Sebastià A.; Torrens, Gabriel; Verd, Jaume; Segura, Jaume

    2015-09-01

    Eight-transistor (8T) cells were introduced to improve variability tolerance, cell stability and low-voltage operation in high-speed SRAM caches by decoupling the read and write design requirements. Altogether, 8T-SRAM can be designed without significant area penalty over 6T-SRAM. Ionizing radiation effects are nowadays a major concern for reliability and dependability of emerging electronic SRAM devices, even for sea-level applications. In this paper we demonstrate from experimental results that the 8T-SRAM also exhibits an enhanced overall intrinsic tolerance to alpha particle radiation even though its critical charge values are smaller than conventional 6T cells. We have experimentally found that the soft error rate measured in accelerated experiments with alpha particles in SRAM devices implemented in a 65 nm CMOS is 56% better for 8T cells with respect to standard 6T-cells. Even more, we show that this value can be increased up to a 200% through transistor sizing optimization.

  13. 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.

  14. 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.

  15. Interpreting Recoil for Undergraduate Students

    ERIC Educational Resources Information Center

    Elsayed, Tarek A.

    2012-01-01

    The phenomenon of recoil is usually explained to students in the context of Newton's third law. Typically, when a projectile is fired, the recoil of the launch mechanism is interpreted as a reaction to the ejection of the smaller projectile. The same phenomenon is also interpreted in the context of the conservation of linear momentum, which is…

  16. 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

  17. 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...

  18. Interpreting Recoil for Undergraduate Students

    NASA Astrophysics Data System (ADS)

    Elsayed, Tarek A.

    2012-04-01

    The phenomenon of recoil is usually explained to students in the context of Newton's third law. Typically, when a projectile is fired, the recoil of the launch mechanism is interpreted as a reaction to the ejection of the smaller projectile. The same phenomenon is also interpreted in the context of the conservation of linear momentum, which is closely related to Newton's third law. Since the actual microscopic causes of recoil differ from one problem to another, some students (and teachers) may not be satisfied with understanding recoil through the principles of conservation of linear momentum and Newton's third law. For these students, the origin of the recoil motion should be presented in more depth.

  19. 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.

  20. 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

  1. 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.

  2. Half-life estimation of the first excited state of {sup 229}Th by using {alpha}-particle spectrometry

    SciTech Connect

    Kikunaga, H.; Kasamatsu, Y.; Haba, H.; Mitsugashira, T.; Hara, M.; Takamiya, K.; Ohtsuki, T.; Yokoyama, A.; Nakanishi, T.; Shinohara, A.

    2009-09-15

    To search for a direct-decay signal from the isomer {sup 229}Th{sup m}, {alpha}-particle spectra of {sup 229}Th{sup m,g} produced from 93 mg of {sup 233}U have been measured by using a rapid and high-resolution {alpha}-particle spectrometry, which can distinguish {alpha} lines of {sup 229}Th{sup m} from those of its ground state. Although {alpha} events were not obtained in the expected energy region for {sup 229}Th{sup m} with the exception of those derived from {sup 229}Th{sup g}, we can estimate that the half-life of {sup 229}Th{sup m} is shorter than 2 h at 3{sigma} confidence level under the chemical condition of chloride or hydroxide.

  3. Transcriptional and Secretomic Profiling of Epidermal Cells Exposed to Alpha Particle Radiation

    PubMed Central

    Chauhan, Vinita; Howland, Matthew; Greene, Hillary Boulay; Wilkins, Ruth C

    2012-01-01

    Alpha (?)-particle emitters are probable isotopes to be used in a terrorist attack. The development of biological assessment tools to identify those who have handled these difficult to detect materials would be an asset to our current forensic capacity. In this study, for the purposes of biomarker discovery, human keratinocytes were exposed to ?-particle and X-radiation (0.98 Gy/h at 0, 0.5, 1.0, 1.5 Gy) and assessed for differential gene and protein expression using microarray and Bio-Plex technology, respectively. Secretomic analysis of supernatants showed expression of two pro-inflammatory cytokines (IL-13 and PDGF-bb) to be exclusively affected in ?-particle exposed cells. The highest dose of ?-particle radiation modulated a total of 67 transcripts (fold change>|1.5|, (False discovery rate) FDR<0.05) in exposed cells. Several genes which responded with high expression levels (>2 fold) included KIF20A, NEFM, C7orf10, HIST1H2BD, BMP6, and HIST1H2AC. Among the high expressing genes, five (CCNB2, BUB1, NEK2, CDC20, AURKA) were also differentially expressed at the medium (1.0 Gy) dose however, these genes were unmodulated following exposure to X-irradiation. Networks of these genes clustered around tumor protein-53 and transforming growth factor-beta signaling. This study has identified some potential gene /protein responses and networks that may be validated further to confirm their specificity and potential to be signature biomarkers of ?-particle exposure. PMID:23002402

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

    SciTech Connect

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

    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.

  5. 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.

  6. Effect of crystal thickness and geometry on the alpha-particle resolution of CsI (Tl)

    USGS Publications Warehouse

    Martinez, P.; Senftle, F.E.

    1960-01-01

    The resolution of CsI(Tl) for Po210 alpha particles has been measured as a function of crystal thickness. The best resolution of a 12;-in. diam cylindrical crystal was obtained for a thickness of 0.38 mm, and the effect of thickness on the resolution is discussed. Based on the proposed model, a conical crystal was designed, which yielded a line width of 1.8% for Po 210 alpha particles with a selected photomultiplier tube. ?? 1960 The American Institute of Physics.

  7. The optical, wettability and hardness properties of polyethylene improved by alpha particle irradiations.

    PubMed

    Zaki, M F

    2015-12-01

    In this work, the optical, chemical and morphological changes of alpha irradiated low-density polyethylene (LDPE) were investigated using UV/Vis spectroscopy, Fourier transform infrared spectrometer (FTIR) and scanning electron microscope (SEM). In addition to, the wettability and Vicker's Micro-Hardness have been studied using the contact angle measurements and Vicker's Micro-Hardness tester. The polymer samples are irradiated with different times of alpha particles. UV/Vis spectra show that the absorbance increases with increase in the irradiation time and the absorption edge shifts toward the higher wavelength. This indicates to a decrease in the optical band gap energy and an increase in number of carbon clusters. FTIR analysis reveals that the formation of CH groups and O-H has been observed and also indicated the presence of unsaturations due to vinyl end groups in the irradiated samples. Noticeable decreases in the contact angle of irradiated samples were observed. This decrease reflects the increase in the wettability and consequently the surface free energy. This behavior is due to the formation of oxidized layer on the irradiated surface polymer. Induced increasing in the Vicker's hardness in the irradiated polymers was observed, that can be attributed to crosslinking effects in the chain of the polymers. PMID:26184467

  8. 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. ); Wilds, E.L. ); Kryger, R.A.; Winger, J.A. ); Beard, K.B. )

    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

  9. [Near infrared distance sensing method for Chang'e-3 alpha particle X-ray spectrometer].

    PubMed

    Liang, Xiao-Hua; Wu, Ming-Ye; Wang, Huan-Yu; Peng, Wen-Xi; Zhang, Cheng-Mo; Cui, Xing-Zhu; Wang, Jin-Zhou; Zhang, Jia-Yu; Yang, Jia-Wei; Fan, Rui-Rui; Gao, Min; Liu, Ya-Qing; Zhang, Fei; Dong, Yi-Fan; Guo, Dong-Ya

    2013-05-01

    Alpha particle X-ray spectrometer (APXS) is one of the payloads of Chang'E-3 lunar rover, the scientific objective of which is in-situ observation and off-line analysis of lunar regolith and rock. Distance measurement is one of the important functions for APXS to perform effective detection on the moon. The present paper will first give a brief introduction to APXS, and then analyze the specific requirements and constraints to realize distance measurement, at last present a new near infrared distance sensing algorithm by using the inflection point of response curve. The theoretical analysis and the experiment results verify the feasibility of this algorithm. Although the theoretical analysis shows that this method is not sensitive to the operating temperature and reflectance of the lunar surface, the solar infrared radiant intensity may make photosensor saturation. The solutions are reducing the gain of device and avoiding direct exposure to sun light. PMID:23905352

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

    E-print Network

    Álvarez, V; 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; Morata, J A Hernando; 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; Vidal, J Muñoz; da Luz, H Natal; Navarro, G; Nebot, M; Nygren, D; Oliveira, C A B; Palma, R; Pérez, J; Aparicio, J L Pérez; Renner, J; Ripoll, L; Rodríguez, A; Rodríguez, J; Santos, F P; Santos, J M F dos; Segui, 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

    2012-01-01

    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 transport properties of ionization electrons, and the mechanism of electron-ion recombination, in 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. Our electron drift velocity and longitudinal diffusion results are similar to expectations based on available electron scattering cross sections on pure xenon, favoring low-diffusion models. In addition, two types of measurements addressing the connection between the ionization and scintillation yields were 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, similarly to what has already bee...

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

    SciTech Connect

    Sasao, M.; Tanaka, N.; Terai, K.; Kaneko, O.; Kisaki, M.; Kobuchi, T.; Tsumori, K.; Okamoto, A.; Kitajima, S.; Shinto, K.; Wada, M.

    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.

  12. Characterization of coal and charcoal by alpha-particle and gamma-ray spectrometry

    NASA Astrophysics Data System (ADS)

    Carrasco Lourtau, A. M.; Rubio Montero, M. P.; Jurado Vargas, M.

    2015-11-01

    Although coal and charcoal have similar physical and chemical characteristics, there are several crystallographic procedures used to distinguish and characterize them. But if the matrix is crushed, there is no standard procedure to distinguish coal from charcoal. In this work, a procedure to characterize coal and charcoal samples based on the radioactive content is proposed. The first assay is by gamma-ray spectrometry, which allows a part of the radioactive content to be determined rapidly and non-destructively. Then, alpha-particle spectrometry is applied to assay the content of those radionuclides which are difficult to determine precisely by gamma-ray spectrometry. This second technique requires prior chemical purification of the carbon sample in order to separate the corresponding radionuclides of interest.

  13. Radiation risk to low fluences of alpha particles may be greater than we thought.

    PubMed

    Zhou, H; Suzuki, M; Randers-Pehrson, G; Vannais, D; Chen, G; Trosko, J E; Waldren, C A; Hei, T K

    2001-12-01

    Based principally on the cancer incidence found in survivors of the atomic bombs dropped in Hiroshima and Nagasaki, the International Commission on Radiation Protection (ICRP) and the United States National Council on Radiation Protection and Measurements (NCRP) have recommended that estimates of cancer risk for low dose exposure be extrapolated from higher doses by using a linear, no-threshold model. This recommendation is based on the dogma that the DNA of the nucleus is the main target for radiation-induced genotoxicity and, as fewer cells are directly damaged, the deleterious effects of radiation proportionally decline. In this paper, we used a precision microbeam to target an exact fraction (either 100% or < or =20%) of the cells in a confluent population and irradiated their nuclei with exactly one alpha particle each. We found that the frequencies of induced mutations and chromosomal changes in populations where some known fractions of nuclei were hit are consistent with non-hit cells contributing significantly to the response. In fact, irradiation of 10% of a confluent mammalian cell population with a single alpha particle per cell results in a mutant yield similar to that observed when all of the cells in the population are irradiated. This effect was significantly eliminated in cells pretreated with a 1 mM dose of octanol, which inhibits gap junction-mediated intercellular communication, or in cells carrying a dominant negative connexin 43 vector. The data imply that the relevant target for radiation mutagenesis is larger than an individual cell and suggest a need to reconsider the validity of the linear extrapolation in making risk estimates for low dose, high linear-energy-transfer (LET) radiation exposure. PMID:11734643

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

    SciTech Connect

    Jaggi, Jaspreet Singh; Seshan, Surya V.; McDevitt, Michael R.; Sgouros, George; Hyjek, Elizabeth; Scheinberg, David A. . 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.

  15. 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

  16. Fission time scale from prescission neutron, proton, and {alpha} particle multiplicities in {sup 28}Si+{sup 175}Lu

    SciTech Connect

    Ramachandran, K.; Chatterjee, A.; Navin, A.; Mahata, K.; Shrivastava, A.; Tripathi, V.; Kailas, S.; Saxena, A.; Thomas, R.G.; Kumar, Suresh; Sahu, P.K.; Nanal, V.; Pillay, R.G.

    2006-06-15

    Prescission neutron, proton, and {alpha}-particle multiplicities for the reaction {sup 28}Si+{sup 175}Lu at 159 MeV were measured simultaneously. The multiplicity data were analyzed using deformation dependent particle transmission coefficients, binding energies, and level densities to extract fission time scales and the mean deformation of the saddle-to-scission emitter. The neutron and charged particle data could be explained consistently, a better fit being obtained by considering the emission of neutrons to be favored toward larger deformation as compared to charged particles. The total fission time scale is deduced as 36-41x10{sup -21}s.

  17. Excitation of high-[ital n] toroidicity-induced shear Alfven eigenmodes by energetic particles and fusion alpha particles in tokamaks

    SciTech Connect

    Fu, G.Y.; Cheng, C.Z. )

    1992-11-01

    The stability of high-[ital n] toroidicity-induced shear Alfven eigenmodes (TAE) in the presence of fusion alpha particles or energetic ions in tokamaks is investigated. The TAE modes are discrete in nature, and thus can easily tap the free energy associated with energetic particle pressure gradient through wave particle resonant interaction. A quadratic form is derived for the high-[ital n] TAE modes using gyrokinetic equation. The kinetic effects of energetic particles are calculated perturbatively using the ideal magnetohydrodynamic (MHD) solution as the lowest-order eigenfunction. The finite Larmor radius (FLR) effects and the finite drift orbit width (FDW) effects are included for both circulating and trapped energetic particles. It is shown that, for circulating particles, FLR and FDW effects have two opposite influences on the stability of the high-[ital n] TAE modes. First, they have the usual stabilizing effects by reducing the wave particle interaction strength. Second, they also have destabilizing effects by allowing more particles to resonate with the TAE modes. It is found that the growth rate induced by the circulating alpha particles increases linearly with the toroidal mode number [ital n] for small [ital k][sub [theta

  18. 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

  19. Study of influence of catechins on bystander responses in alpha-particle radiobiological experiments using thin PADC films

    E-print Network

    Yu, Peter K.N.

    , leading to a variety of biological effects via a bystander effect. An earlier study showed that bystander of only 0.1-1% of cell nuclei (Nagasawa and Little, 1992). Bystander effect has been demonstrated for both such as alpha particles. Although the underlying mechanisms of the bystander effect are not yet well understood

  20. 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.

    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.

  1. Production of the Alpha-Particle Emitting Radionuclide Astatine-211 at the Texas A&M Cyclotron Institute 

    E-print Network

    Bhakta, Viharkumar Satish

    2011-10-21

    The need of a stable production of At-211 is necessary to continue research in alpha-particle targeted radionuclide therapy. Our objectives were to establish the production of Astatine-211 at Texas A&M Cyclotron Institute, optimize the production...

  2. PPPL3239 Preprint: March 1997, UC420, 427 Calculations of alpha particle loss for reversed magnetic shear

    E-print Network

    magnetic shear in the Tokamak Fusion Test Reactor M. H. Redi, R. B. White, S. H. Batha, F. M. Levinton, DPPPL­3239 ­ Preprint: March 1997, UC­420, 427 Calculations of alpha particle loss for reversed losses to be greater than those from a comparable non­reversed magnetic shear plasma in the Tokamak

  3. Alpha particle-driven toroidal Alfven eigenmodes in Tokamak Fusion Test Reactor deuteriumtritium plasmas: Theory and experiments

    E-print Network

    Fu, Guoyong

    Alpha particle-driven toroidal Alfve´n eigenmodes in Tokamak Fusion Test Reactor deuterium August 1998 The toroidal Alfve´n eigenmodes TAE in the Tokamak Fusion Test Reactor K. Young et al localized on the high field side of the magnetic axis with a mode frequency substantially below the TAE

  4. 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 en eigenmodes TAE in the Tokamak Test Fusion Reactor K. Young et al., Plasma Phys. Controlled Fusion on the high eld side of the magnetic axis with a mode frequency substantially below the TAE frequency. 52

  5. 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.

  6. Computation of Cosmic Ray Ionization and Dose at Mars: a Comparison of HZETRN and Planetocosmics for Proton and Alpha Particles

    NASA Technical Reports Server (NTRS)

    Gronoff, Guillaume; Norman, Ryan B.; Mertens, Christopher J.

    2014-01-01

    The ability to evaluate the cosmic ray environment at Mars is of interest for future manned exploration. To support exploration, tools must be developed to accurately access the radiation environment in both free space and on planetary surfaces. The primary tool NASA uses to quantify radiation exposure behind shielding materials is the space radiation transport code, HZETRN. In order to build confidence in HZETRN, code benchmarking against Monte Carlo radiation transport codes is often used. This work compares the dose calculations at Mars by HZETRN and the Geant4 application Planetocosmics. The dose at ground and the energy deposited in the atmosphere by galactic cosmic ray protons and alpha particles has been calculated for the Curiosity landing conditions. In addition, this work has considered Solar Energetic Particle events, allowing for the comparison of varying input radiation environments. The results for protons and alpha particles show very good agreement between HZETRN and Planetocosmics.

  7. 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.

  8. Interaction of the human cytomegalovirus particle with the host cell induces hypoxia-inducible factor 1 alpha

    SciTech Connect

    McFarlane, Steven; Nicholl, Mary Jane; Sutherland, Jane S.; Preston, Chris M.

    2011-05-25

    The cellular protein hypoxia-inducible factor 1 alpha (HIF-1{alpha}) was induced after infection of human fibroblasts with human cytomegalovirus (HCMV). HCMV irradiated with ultraviolet light (uv-HCMV) also elicited the effect, demonstrating that the response was provoked by interaction of the infecting virion with the cell and that viral gene expression was not required. Although induction of HIF-1{alpha} was initiated by an early event, accumulation of the protein was not detected until 9 hours post infection, with levels increasing thereafter. Infection with uv-HCMV resulted in increased abundance of HIF-1{alpha}-specific RNA, indicating stimulation of transcription. In addition, greater phosphorylation of the protein kinase Akt was observed, and the activity of this enzyme was required for induction of HIF-1{alpha} to occur. HIF-1{alpha} controls the expression of many cellular gene products; therefore the findings reveal new ways in which interaction of the HCMV particle with the host cell may cause significant alterations to cellular physiology.

  9. Alpha spectrometric characterization of process-related particle size distributions from active particle sampling at the Los Alamos National Laboratory uranium foundry

    SciTech Connect

    Plionis, Alexander A; Peterson, Dominic S; Tandon, Lav; Lamont, Stephen P

    2009-01-01

    Uranium particles within the respirable size range pose a significant hazard to the health and safety of workers. Significant differences in the deposition and incorporation patterns of aerosols within the respirable range can be identified and integrated into sophisticated health physics models. Data characterizing the uranium particle size distribution resulting from specific foundry-related processes are needed. Using personal air sampling cascade impactors, particles collected from several foundry processes were sorted by activity median aerodynamic diameter onto various Marple substrates. After an initial gravimetric assessment of each impactor stage, the substrates were analyzed by alpha spectrometry to determine the uranium content of each stage. Alpha spectrometry provides rapid nondestructive isotopic data that can distinguish process uranium from natural sources and the degree of uranium contribution to the total accumulated particle load. In addition, the particle size bins utilized by the impactors provide adequate resolution to determine if a process particle size distribution is: lognormal, bimodal, or trimodal. Data on process uranium particle size values and distributions facilitate the development of more sophisticated and accurate models for internal dosimetry, resulting in an improved understanding of foundry worker health and safety.

  10. Field Theory of the d+t -> n+alpha Reaction Dominated by a 5He* Unstable Particle

    E-print Network

    Lowell S. Brown; Gerald M. Hale

    2013-08-01

    An effective, non-relativistic field theory for low-energy d+t -> n+alpha reaction is presented. The theory assumes that the reaction is dominated by an intermediate 5He* unstable spin 3/2+ resonance. It involves two parameters in the coupling of the d+t and n+alpha particles to the unstable resonant state, and the resonance energy level -- only three real parameters in all. All Coulomb corrections to this process are computed. The resultant field theory is exactly solvable and provides an excellent description of the d+t fusion process.

  11. 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.

  12. 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

  13. 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.

    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.

  14. Directional recoil rate for direct detection of WIMPs

    NASA Astrophysics Data System (ADS)

    Alenazi, Moqbil; Gondolo, Paolo

    2007-10-01

    The problem of directional direct detection of weakly interacting massive particles (WIMPs) dark matter (DM) is investigated. We compute, analytically and numerically, the directional differential recoil rate dRd? of recoiled target nuclei hit by WIMPs in direct detection experiments in terms of the angle ?, which is the angle between the reference direction and the recoil direction. While the analytic method is for fixed reference direction and Gaussian distribution of WIMPs, the numeric method is a general method. The two methods give the same results. We apply the numeric method to various Maxwellian distributions including; a stream of WIMPs, the standard dark halo, streams of WIMPs from Sikivie's late-infall (SLI) halo model, and streams with anisotropic velocity distributions. We show the results as distributions of the nuclei's directional differential recoil rate dRd? as a function of ?. We introduce a `folded' directional differential recoil rate dRd|?| to overcome the difficulty of head-tail discrimination in some WIMP's direct detectors. We conclude that dRd|?| can be helpful in recognizing cases of anisotropic streams and isotropic standard dark halo but not in the case of SLI streams.

  15. Median recoil direction as a WIMP directional detection signal

    SciTech Connect

    Green, Anne M.; Morgan, Ben

    2010-03-15

    Direct detection experiments have reached the sensitivity to detect dark matter weakly interacting massive particles (WIMPs). Demonstrating that a putative signal is due to WIMPs, and not backgrounds, is a major challenge, however. The direction dependence of the WIMP scattering rate provides a potential WIMP 'smoking gun'. If the WIMP distribution is predominantly smooth, the Galactic recoil distribution is peaked in the direction opposite to the direction of Solar motion. Previous studies have found that, for an ideal detector, of order 10 WIMP events would be sufficient to reject isotropy, and rule out an isotropic background. We examine how the median recoil direction could be used to confirm the WIMP origin of an anisotropic recoil signal. Specifically, we determine the number of events required to confirm the direction of solar motion as the median inverse recoil direction at 95% confidence. We find that for zero background 31 events are required, a factor of {approx}2 more than are required to simply reject isotropy. We also investigate the effect of a nonzero isotropic background. As the background rate is increased the number of events required increases, initially fairly gradually and then more rapidly, once the signal becomes subdominant. We also discuss the effect of features in the speed distribution at large speeds, as found in recent high resolution simulations, on the median recoil direction.

  16. Recoil-decay tagging spectroscopy of 74162W88

    NASA Astrophysics Data System (ADS)

    Li, H. J.; Cederwall, B.; Bäck, T.; Qi, C.; Doncel, M.; Jakobsson, U.; Auranen, K.; Bönig, S.; Drummond, M. C.; Grahn, T.; Greenlees, P.; HerzáÅ, A.; Julin, R.; Juutinen, S.; Konki, J.; Kröll, T.; Leino, M.; McPeake, C.; O'Donnell, D.; Page, R. D.; Pakarinen, J.; Partanen, J.; Peura, P.; Rahkila, P.; Ruotsalainen, P.; Sandzelius, M.; Sarén, J.; Say??, B.; Scholey, C.; Sorri, J.; Stolze, S.; Taylor, M. J.; Thornthwaite, A.; Uusitalo, J.; Xiao, Z. G.

    2015-07-01

    Excited states in the highly neutron-deficient nucleus 162W have been investigated via the 92Mo (78Kr,2? ) 162W reaction. Prompt ? rays were detected by the JUROGAM II high-purity germanium detector array and the recoiling fusion-evaporation products were separated by the recoil ion transport unit (RITU) gas-filled recoil separator and identified with the gamma recoil electron alpha tagging (GREAT) spectrometer at the focal plane of RITU. ? rays from 162W were identified uniquely using mother-daughter and mother-daughter-granddaughter ? -decay correlations. The observation of a rotational-like ground-state band is interpreted within the framework of total Routhian surface (TRS) calculations, which suggest an axially symmetric ground-state shape with a ? -soft minimum at ?2?0.15 . Quasiparticle alignment effects are discussed based on cranked shell model calculations. New measurements of the 162W ground-state ? -decay energy and half-life were also performed. The observed ? -decay energy agrees with previous measurements. The half-life of 162W was determined to be t1 /2=990 (30 ) ms. This value deviates significantly from the currently adopted value of t1 /2=1360 (70 ) ms. In addition, the ? -decay energy and half-life of 166Os were measured and found to agree with the adopted values.

  17. Nanodosimetry and nanodosimetric-based models of radiation action for radon alpha particles. Progress report, July 1990--June 1992

    SciTech Connect

    Zaider, M.

    1992-12-31

    We report on a theory for describing the biological effects of ionizing radiation in particular radon {alpha} particles. Behind this approach is the recognition that biological effects such as chromosome aberrations, cellular transformation, cellular inactivation, etc, are the result of a hierarchic sequence of radiation effects. We indicate how to treat each of the individual processes in this sequence, and also how to relate one effect to the hierarchically superior one.

  18. Optical Model Potential Parameters for p, d, {sup 3}He and Alpha-Particle Scattering on Lithium Nuclei

    SciTech Connect

    Burtebayev, N.; Nassurlla, Marzhan; Nassurlla, Maulen; Kerimkulov, Zh. K.; Sakuta, S. B.

    2008-11-11

    Analysis of the p, d, {sup 3}He and {alpha}-particles elastic scattering on the {sup 6}Li and {sup 7}Li nuclei has been done in the framework of the optical model at the beam energies up to 72 MeV. It was shown that the account of the cluster exchange mechanism together with the potential scattering allow reproducing the experimental cross-sections in the whole angular range.

  19. Angular distributions of the alpha particle production in the 7Li+144Sm system at near-barrier energies

    NASA Astrophysics Data System (ADS)

    Carnelli, P. F. F.; Arazi, A.; Capurro, O. A.; Fernández Niello, J. O.; Martinez Heimann, D.; Pacheco, A. J.; Cardona, M. A.; de Barbará, E.; Figueira, J. M.; Hojman, D. L.; Martí, G. V.; Negri, A. E.

    2015-07-01

    We have studied the production of alpha particles in reactions induced by 7Li projectiles on a 144Sm target at bombarding energies of 18, 24 and 30 MeV over the 15°-140° angular range. The purpose of the investigation has been to determine the contribution of different mechanisms in reactions that involve weakly bound projectiles. We have included in our analysis several processes that can either directly or sequentially lead to the emission of alpha particles: complete fusion, direct transfer of 3H, capture breakup (incomplete fusion, sequential complete fusion) and non-capture breakup. In order to distinguish alpha particles stemming from these processes it is necessary to determine the mass and charge of the reaction products and to obtain precise measurements of their energies and scattering angles over relatively wide ranges of these variables. We have done this using a detection system consisting of an ionization chamber plus three position sensitive detectors. We present results of these measurements and a preliminary interpretation based on kinematical considerations and comparisons with predictions from a statistical model.

  20. Dependence of alpha particle track diameter on the free volume holes size using positron annihilation lifetime technique

    NASA Astrophysics Data System (ADS)

    El-Gamal, S.; Abdalla, Ayman M.; Abdel-Hady, E. E.

    2015-09-01

    The alpha particle track diameter dependence of the free volume holes size (Vf) in DAM-ADC and CR-39 nuclear track detectors was investigated using positron annihilation lifetime technique. The effect of temperature on the alpha particle track diameter and free volume were also investigated in the T-range (RT-130 °C). The obtained results revealed that the values of ortho-positronium lifetime ?3 and Vf increases while I3 slightly increases as T increases for the two detectors. The values of ?3, Vf and I3 are higher in CR-39 than DAM-ADC. The interpretation of obtained results is based on the fact that increasing T leads to significant enhancement of thermal expansion of the polymer matrix and consequently Vf increases. The track diameter increases as T increases. This can be explained by the fact that the increase in T increases the crystal size and Vf in the polymer. A relationship between Vf and the alpha particle track diameter was obtained. Moreover results of detector irradiation, along with free volume evaluation are addressed and thoroughly discussed.

  1. Electron recombination in low-energy nuclear recoils tracks in liquid argon

    E-print Network

    Wojcik, Mariusz

    2015-01-01

    This paper presents an analysis of electron-ion recombination processes in ionization tracks of recoiled atoms in liquid argon (LAr) detectors. The analysis is based on the results of computer simulations which use realistic models of electron transport and reactions. The calculations reproduce the recent experimental results of the ionization yield from 6.7 keV nuclear recoils in LAr. The statistical distribution of the number of electrons that escape recombination is found to deviate from the binomial distribution, and estimates of recombination fluctuations for nuclear recoils tracks are obtained. A study of the recombination kinetics shows that a significant part of electrons undergo very fast static recombination, an effect that may be responsible for the weak drift-field dependence of the ionization yield from nuclear recoils in some noble liquids. The obtained results can be useful in the search for hypothetical dark matter particles and in other studies that involve detection of recoiled nuclei.

  2. In situ and time resolved study of the {gamma}/{alpha}-Fe{sub 2}O{sub 3} transition in nanometric particles

    SciTech Connect

    Belin, T. Millot, N. Bovet, N.; Gailhanou, M.

    2007-08-15

    In situ and real-time study of the {gamma} to {alpha}-Fe{sub 2}O{sub 3} transition is carried out on the H10 beamline at LURE (France). {gamma}-Fe{sub 2}O{sub 3} particles are synthesized by soft chemistry. These particles have an average diameter evaluated by X-ray diffraction of 9{+-}1nm and a specific surface area of 116m{sup 2}g{sup -1}. The size of produced {alpha}-Fe{sub 2}O{sub 3} particles is determined by in situ and time resolved X-ray diffraction measurements at different temperatures. An amazing evolution of size with time is revealed: an abrupt doubling of the {alpha}-Fe{sub 2}O{sub 3} particle size is observed whatever the heating temperature. Some assumptions are given in order to explain this phenomenon which implies at the same time surface energy, granulometric distribution and coalescence of particles. -- A brutal increase of the X-rays coherent domain sizes of the {alpha}-Fe{sub 2}O{sub 3} particles during the {gamma}/{alpha} transition at nanometric scale. Maghemite {gamma}-Fe{sub 2}O{sub 3} particles ({phi}=9{+-}1nm) were heated at 723 K. First germs (or grains) of {alpha}-Fe{sub 2}O{sub 3} were detected with a size of 2 nm.

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

    SciTech Connect

    Joshi, T.; Sangiorgio, Samuele; Bernstein, A.; Foxe, Michael P.; Hagmann, Chris; Jovanovic, Igor; Kazkaz, K.; Mozin, Vladimir V.; Norman, E. B.; Pereverzev, S. V.; Rebassoo, Finn O.; Sorensen, Peter F.

    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.

  4. Overview of the first workshop on alpha particle physics in TFTR

    SciTech Connect

    Zweben, S.J.; Biglari, H.

    1991-07-01

    The First Workshop on Alpha Physics in TFTR'' was held at the Princeton Plasma Physics Lab March 28--29, 1991. The motivation for this meeting was to clarify and strengthen the TFTR alpha physics program, and to increase the involvement of the fusion community outside PPPL in the TFTR D-T experiments. Therefore the meeting was sharply focused on alpha physics relevant to the upcoming TFTR D-T simulation, and was asked to devote half of his talk to specific TFTR issues. The Workshop consisted of 27 talks on: (1) experimental possibilities; (2) theoretical possibilities; (3) diagnostic possibilities; (4) relevance for future machines; and (5) discussion/summary session. This summary contains a brief sampling of the new results and ideas brought out by these talks, followed by two more general overviews of the status of experiment and theory.

  5. Modelling TF ripple loss of alpha particles in TFTR DT experiments

    SciTech Connect

    Redi, M.H.; Budny, R.V.; Darrow, D.S.

    1995-07-01

    Modelling of TF ripple loss of alphas in DT experiments on TFTR now includes neoclassical calculations of first orbit loss, stochastic ripple diffusion, ripple trapping and collisional effects. A rapid way to simulate experiment has been developed which uses a simple stochastic domain model for TF ripple loss within the TRANSP analysis code, with the ripple diffusion threshold evaluated by comparison with more accurate but computationally expensive Hamiltonian coordinate guiding center code simulations. Typical TF collisional ripple loss predictions are 6-10% loss of alphas for TFTR D-T experiments at I{sub p} = 1.0-2.0 MA and R = 2.52 m.

  6. Simulation of the alpha particle heating and the helium ash source in an International Thermonuclear Experimental Reactor-like tokamak with an internal transport barrier

    SciTech Connect

    Ye, Lei Guo, Wenfeng; Xiao, Xiaotao; Dai, Zongliang; Wang, Shaojie

    2014-12-15

    A guiding center orbit following code, which incorporates a set of non-singular coordinates for orbit integration, was developed and applied to investigate the alpha particle heating in an ITER-like tokamak with an internal transport barrier. It is found that a relatively large q (safety factor) value can significantly broaden the alpha heating profile in comparison with the local heating approximation; this broadening is due to the finite orbit width effects; when the orbit width is much smaller than the scale length of the alpha particle source profile, the heating profile agrees with the source profile, otherwise, the heating profile can be significantly broadened. It is also found that the stagnation particles move to the magnetic axis during the slowing-down process, thus the effect of stagnation orbits is not beneficial to the helium ash removal. The source profile of helium ash is broadened in comparison with the alpha source profile, which is similar to the heating profile.

  7. 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

  8. Response of Ni/4H-SiC Schottky barrier diodes to alpha-particle irradiation at different fluences

    NASA Astrophysics Data System (ADS)

    Omotoso, E.; Meyer, W. E.; Auret, F. D.; Diale, M.; Ngoepe, P. N. M.

    2016-01-01

    Irradiation experiments have been carried out on 1.9×1016 cm-3 nitrogen-doped 4H-SiC at room temperature using 5.4 MeV alpha-particle irradiation over a fluence ranges from 2.6×1010 to 9.2×1011 cm-2. Current-voltage (I-V), capacitance-voltage (C-V) and deep level transient spectroscopy (DLTS) measurements have been carried out to study the change in characteristics of the devices and free carrier removal rate due to alpha-particle irradiation, respectively. As radiation fluence increases, the ideality factors increased from 1.20 to 1.85 but the Schottky barrier height (SBHI-V) decreased from 1.47 to 1.34 eV. Free carrier concentration, Nd decreased with increasing fluence from 1.7×1016 to 1.1×1016 cm-2 at approximately 0.70 ?m depth. The reduction in Nd shows that defects were induced during the irradiation and have effect on compensating the free carrier. The free carrier removal rate was estimated to be 6480±70 cm-1. Alpha-particle irradiation introduced two electron traps (E0.39 and E0.62), with activation energies of 0.39±0.03 eV and 0.62±0.08 eV, respectively. The E0.39 as attribute related to silicon or carbon vacancy, while the E0.62 has the attribute of Z1/Z2.

  9. Detection of Alpha Particles and Low Energy Gamma Rays by Thermo-Bonded Micromegas in Xenon Gas

    E-print Network

    Yuehuan Wei; Liang Guan; Zhiyong Zhang; Qing Lin; Xiaolian Wang; Kaixuan Ni; Tianchi Zhao

    2013-08-09

    Micromegas is a type of micro-pattern gaseous detector currently under R&D for applications in rare event search experiments. Here we report the performance of a Micromegas structure constructed with a micromesh thermo-bonded to a readout plane, motivated by its potential application in two-phase xenon detectors for dark matter and neutrinoless double beta decay experiments. The study is carried out in pure xenon at room temperature. Measurements with alpha particles from the Americium-241 source showed that gas gains larger than 200 can be obtained at xenon pressure up to 3 atm. Gamma rays down to 8 keV were observed with such a device.

  10. 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.

  11. Detection of Alpha Particles and Low Energy Gamma Rays by Thermo-Bonded Micromegas in Xenon Gas

    E-print Network

    Wei, Yuehuan; Zhang, Zhiyong; Lin, Qing; Wang, Xiaolian; Ni, Kaixuan; Zhao, Tianchi

    2013-01-01

    Micromegas is a type of micro-pattern gaseous detector currently under R&D for applications in rare event search experiments. Here we report the performance of a Micromegas structure constructed with a micromesh thermo-bonded to a readout plane, motivated by its potential application in two-phase xenon detectors for dark matter and neutrinoless double beta decay experiments. The study is carried out in pure xenon at room temperature. Measurements with alpha particles from the Americium-241 source showed that gas gains larger than 200 can be obtained at xenon pressure up to 3 atm. Gamma rays down to 8 keV were observed with such a device.

  12. Alpha-Cluster Model, Charge Symmetry of Nuclear Force and Single Particle Bound State Potential in Symmetrical Nuclei

    E-print Network

    G. K. Nie

    2011-06-21

    A phenomenological alpha-cluster model based on the charge symmetry of nuclear force allows one to estimate the last proton position radius (LPPR) in a symmetrical nucleus. The values of LPPR obtained for the symmetrical nuclei with 5=15 it is inappropriate to represent a single particle bound state by the Woods-Saxon potential. For the nuclei with 5<=Z<=14 the error of the spectroscopic factor obtained with standard parameters in DWBA analysis of pure peripheral one nucleon transfer reactions is estimated. It is shown that for some nuclei using the standard parameters brings an error more than 20%.

  13. 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.

  14. Influence of catechins on bystander responses in CHO cells induced by alpha-particle irradiation

    E-print Network

    Yu, Peter K.N.

    , Tat Chee Avenue, Kowloon Tong, Hong Kong a r t i c l e i n f o Keywords: Bystander effect Alpha-mediated bystander effects in Chinese hamster ovary (CHO) cells through micronucleus (MN) assay. We showed proved the protection effect of catechins on bystander cells from radiation. & 2009 Elsevier Ltd. All

  15. Feasibility studies of colorless LR 115 SSNTD for alpha-particle radiobiological experiments

    E-print Network

    Yu, Peter K.N.

    on the top side was more desirable. In relation to this, culture of HeLa cells on the bottom side HeLa cells. The feasibility is assessed by taking photographs of the HeLa cells and alpha of the active layer was found feasible although the cultured cell number was relatively smaller. The fea

  16. 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.

  17. A Comparitive Assessement of Cytokine Expression in Human-Derived Cell Lines Exposed to Alpha Particles and X-Rays

    PubMed Central

    Chauhan, Vinita; Howland, Matthew; Wilkins, Ruth

    2012-01-01

    Alpha- (?-) particle radiation exposure has been linked to the development of lung cancer and has been identified as a radiation type likely to be employed in radiological dispersal devices. Currently, there exists a knowledge gap concerning cytokine modulations associated with exposure to ?-particles. Bio-plex technology was employed to investigate changes in proinflammatory cytokines in two human-derived cell lines. Cells were irradiated at a dose of 1.5?Gy to either ?-particles or X-rays at equivalent dose rates. The two cell lines exhibited a unique pattern of cytokine expression and the response varied with radiation type. Of the 27 cytokines assessed, only vascular endothelin growth factor (VEGF) was observed to be modulated in both cell lines solely after ?-particle exposure, and the expression of VEGF was shown to be dose responsive. These results suggest that certain proinflammatory cytokines may be involved in the biological effects related to ?- particle exposure and the responses are cell type and radiation type specific. PMID:22619631

  18. Interpreting Recoil Motion for Undergraduate Students

    E-print Network

    Mokhiemer, Tarek Ahmed

    2007-01-01

    In this paper, I outline some problems in the students' understanding of the reason of recoil motion when introduced to them in the context of Newton's third law. I propose to explain the origin of recoil and the fundamental mechanism which produces this motion when presenting recoil to students to give them more insight into the physical processes involved. This mechanism differs from one system to another. Several examples that can be easily implemented in the classroom environment are given in this paper. Such a deep understanding of recoil may reflect on the level of understanding of other physical phenomena sought by students.

  19. 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.

  20. Influence of Alpha-Particles on Parameters of Plasma Confined in Open Traps

    NASA Astrophysics Data System (ADS)

    Chebotaev, P. Z.

    1987-01-01

    The numerical calculations of the longitudinal motion in multi-mirror reactor have shown that the energy contribution of ?-particles has substantial influence on the gain factor (the given off thermonuclear energy/ the initial imparted energy) in the temperature region 5-7 keV. The numerical technique has been developed that takes into account the radial distribution of ?-particles caused by their drag on electrons. This effect is substantial for varrho?/R >= 1/2 (where varrho? is ?-particles gyro radius, R is a plasma radius), e.g. for Gas-Dynamic trap. In a Tandem-Mirror reactor some part of fusion ?-particles have the probability to slow down to the plasma energy, that can lead to the `poisoning' of the reactor by the thermonuclear reaction products. The fusion ?-particles can have a strong effect on accumulation of impurities with z <= 15 and thermal ?-particles in TMR.

  1. Dissipation of Parallel and Oblique Alfvén-Cyclotron Waves—Implications for Heating of Alpha Particles in the Solar Wind

    NASA Astrophysics Data System (ADS)

    Maneva, Y. G.; Viñas, Adolfo F.; Moya, Pablo S.; Wicks, Robert T.; Poedts, Stefaan

    2015-11-01

    We perform 2.5D hybrid simulations with massless fluid electrons and kinetic particle-in-cell ions to study the temporal evolution of ion temperatures, temperature anisotropies, and velocity distribution functions in relation to the dissipation and turbulent evolution of a broadband spectrum of parallel and obliquely propagating Alfvén-cyclotron waves. The purpose of this paper is to study the relative role of parallel versus oblique Alfvén-cyclotron waves in the observed heating and acceleration of alpha particles in the fast solar wind. We consider collisionless homogeneous multi-species plasma, consisting of isothermal electrons, isotropic protons, and a minor component of drifting ? particles in a finite-? fast stream near the Earth. The kinetic ions are modeled by initially isotropic Maxwellian velocity distribution functions, which develop nonthermal features and temperature anisotropies when a broadband spectrum of low-frequency nonresonant, ? ? 0.34 ?p, Alfvén-cyclotron waves is imposed at the beginning of the simulations. The initial plasma parameter values, such as ion density, temperatures, and relative drift speeds, are supplied by fast solar wind observations made by the Wind spacecraft at 1 AU. The imposed broadband wave spectra are left-hand polarized and resemble Wind measurements of Alfvénic turbulence in the solar wind. The imposed magnetic field fluctuations for all cases are within the inertial range of the solar wind turbulence and have a Kraichnan-type spectral slope ? = ?3/2. We vary the propagation angle from ? = 0° to ? = 30° and ? = 60°, and find that the heating of alpha particles is most efficient for the highly oblique waves propagating at 60°, whereas the protons exhibit perpendicular cooling at all propagation angles.

  2. Measurement of $?$-particle quenching in LAB based scintillator in independent small-scale experiments

    E-print Network

    B. von Krosigk; M. Chen; S. Hans; A. R. Junghans; T. Kögler; C. Kraus; L. Kuckert; X. Liu; R. Nolte; H. M. O'Keeffe; H. S. Wan Chan Tseung; J. R. Wilson; A. Wright; M. Yeh; K. Zuber

    2015-10-02

    The $\\alpha$-particle light response of liquid scintillators based on linear alkylbenzene (LAB) has been measured with three different experimental approaches. In the first approach, $\\alpha$-particles were produced in the scintillator via $^{12}$C($n$,$\\alpha$)$^9$Be reactions. In the second approach, the scintillator was loaded with 2% of $^{\\mathrm{nat}}$Sm providing an $\\alpha$-emitter, $^{147}$Sm, as an internal source. In the third approach, a scintillator flask was deployed into the water-filled SNO+ detector and the radioactive contaminants $^{222}$Rn, $^{218}$Po and $^{214}$Po provided the $\\alpha$-particle signal. The behavior of the observed $\\alpha$-particle light outputs are in agreement with each case successfully described by Birks' law. The resulting Birks parameter $kB$ ranges from $(0.0071\\pm0.0003)$ cm/MeV to $(0.0076\\pm0.0003)$ cm/MeV. In the first approach, the $\\alpha$-particle light response was measured simultaneously with the light response of recoil protons produced via neutron-proton elastic scattering. This enabled a first time a direct comparison of $kB$ describing the proton and the $\\alpha$-particle response of LAB based scintillator. The observed $kB$ values describing the two light response functions deviate by more than $5\\sigma$. The presented results are valuable for all current and future detectors, using LAB based scintillator as target, since they depend on an accurate knowledge of the scintillator response to different particles.

  3. 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.

  4. Screening materials with the XIA UltraLo alpha particle counter at Southern Methodist University

    NASA Astrophysics Data System (ADS)

    Nakib, M. Z.; Cooley, J.; Guiseppe, V. E.; Kara, B.; Qiu, H.; Rielage, K.; Schnee, R. W.; Scorza, S.

    2013-08-01

    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 cm2 or 1800 cm2 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 210Pb and comparing the effectiveness of cleaning procedures in removing 222Rn progenies from the samples.

  5. 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.; Guiseppe, V. E.; Rielage, K.; Schnee, R. W.

    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.

  6. Localized cyclotron mode driven by fast alpha particles under a nonuniform magnetic field

    SciTech Connect

    Chen, K. R.; Tsai, T. H.; Chen, L.

    2010-02-15

    Resonance requires precise synchronization. Surprisingly, relativistic cyclotron instability can survive under a magnetic field with its nonuniformity larger than the requirement of synchronism. Localized eigenmode observed in a hybrid simulation is found to be consistent with that predicted by an analytical theory including both profile and eigenvalue. Half of the spatial area of the wave profile is located where the frequency mismatch is negative as against to the positive requirement generally believed. The consequence on the alpha dynamics is also demonstrated.

  7. Remnant mass, spin, and recoil from spin aligned black-hole binaries

    E-print Network

    Healy, James; Zlochower, Yosef

    2014-01-01

    We perform a set of 36 nonprecessing black-hole binary simulations with spins either aligned or counteraligned with the orbital angular momentum in order to model the final mass, spin, and recoil of the merged black hole as a function of the individual black hole spin magnitudes and the mass ratio of the progenitors. We find that the maximum recoil for these configurations is $V_{max}=526\\pm23\\,km/s$, which occurs when the progenitor spins are maximal, the mass ratio is $q_{max}=m_1/m_2=0.623\\pm0.038$, the smaller black-hole spin is aligned with the orbital angular momentum, and the larger black-hole spin is counteraligned ($\\alpha_1=-\\alpha_2=1$). This maximum recoil is about $80\\,km/s$ larger than previous estimates, but most importantly, because the maximum occurs for smaller mass ratios, the probability for a merging binary to recoil faster than $400\\,km/s$ can be as large as $17\\%$, while the probability for recoils faster than $250\\, km/s$ can be as large as $45\\%$. We provide explicit phenomenological ...

  8. Trojan horse particle invariance studied with the {sup 6}Li(d,{alpha}){sup 4}He and {sup 7}Li(p,{alpha}){sup 4}He reactions

    SciTech Connect

    Pizzone, R. G.; Spitaleri, C.; Lamia, L.; Cherubini, S.; La Cognata, M.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Bertulani, C.; Mukhamedzhanov, A.; Blokhintsev, L.; Burjan, V.; Hons, Z.; Kroha, V.; Mrazek, J.; Piskor, S.; Kiss, G. G.; Li, C.; Tumino, A.

    2011-04-15

    The Trojan horse nucleus invariance for the binary reaction cross section extracted from the Trojan horse reaction was tested using the quasifree {sup 3}He({sup 6}Li,{alpha}{alpha})H and {sup 3}He({sup 7}Li,{alpha}{alpha}){sup 2}H reactions. The cross sections for the {sup 6}Li(d,{alpha}){sup 4}He and {sup 7}Li(p,{alpha}){sup 4}He binary processes were extracted in the framework of the plane wave approximation. They are compared with direct behaviors as well as with cross sections extracted from previous indirect investigations of the same binary reactions using deuteron as the Trojan horse nucleus instead of {sup 3}He. The very good agreement confirms the applicability of the plane wave approximation which suggests the independence of the binary indirect cross section on the chosen Trojan horse nucleus, at least for the investigated cases.

  9. 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.

  10. 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.

  11. Radiative recoil corrections to hyperfine splitting: Polarization insertions in the electron factor

    SciTech Connect

    Eides, M. I.; Shelyuto, V. A.

    2010-01-15

    We consider three-loop radiative recoil corrections to hyperfine splitting in muonium due to insertions of the one-loop polarization operator in the electron factor. The contribution generated by electron polarization insertions is a cubic polynomial in the large logarithm of the electron-muon mass ratio. The leading logarithm cubed and logarithm squared terms are well known for some time. We calculate all single-logarithmic and nonlogarithmic radiative recoil corrections of the order {alpha}{sup 3}(m/M)E{sub F} generated by diagrams with the electron and muon polarization insertions.

  12. 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

  13. The Collective Atomic Recoil Laser

    SciTech Connect

    Courteille, Ph.W.; Cube, C. avon; Deh, B.; Kruse, D.; Ludewig, A.; Slama, S.; Zimmermann, C.

    2005-05-05

    An ensemble of periodically ordered atoms coherently scatters the light of an incident laser beam. The scattered and the incident light may interfere and give rise to a light intensity modulation and thus to optical dipole forces which, in turn, emphasize the atomic ordering. This positive feedback is at the origin of the collective atomic recoil laser (CARL). We demonstrate this dynamics using ultracold atoms confined by dipole forces in a unidirectionally pumped far red-detuned high-finesse optical ring cavity. Under the influence of an additional dissipative force exerted by an optical molasses the atoms, starting from an unordered distribution, spontaneously form a density grating moving at constant velocity. Additionally, steady state lasing is observed in the reverse direction if the pump laser power exceeds a certain threshold. We compare the dynamics of the atomic trajectories to the behavior of globally coupled oscillators, which exhibit phase transitions from incoherent to coherent states if the coupling strength exceeds a critical value.

  14. Quantum design using a multiple internal reflections method in a study of fusion processes in the capture of alpha-particles by nuclei

    E-print Network

    Sergei P. Maydanyuk; Peng-Ming Zhang; Sergei V. Belchikov

    2015-04-02

    A high precision method to determine fusion in the capture of $\\alpha$-particles by nuclei is presented. For $\\alpha$-capture by $^{40}{\\rm Ca}$ and $^{44}{\\rm Ca}$, such an approach gives (1) the parameters of the $\\alpha$--nucleus potential and (2) fusion probabilities. This method found new parametrization and fusion probabilities and decreased the error by $41.72$ times for $\\alpha + ^{40}{\\rm Ca}$ and $34.06$ times for $\\alpha + ^{44}{\\rm Ca}$ in a description of experimental data in comparison with existing results. We show that the sharp angular momentum cutoff proposed by Glas and Mosel is a rough approximation, Wong's formula and the Hill-Wheeler approach determine the penetrability of the barrier without a correct consideration of the barrier shape, and the WKB approach gives reduced fusion probabilities. Based on our fusion probability formula, we explain the difference between experimental cross-sections for $\\alpha + ^{40}{\\rm Ca}$ and $\\alpha + ^{44}{\\rm Ca}$, which is connected with the theory of coexistence of the spherical and deformed shapes in the ground state for nuclei near the neutron magic shell $N=20$. To provide deeper insight into the physics of nuclei with the new magic number $N=26$, the cross-section for $\\alpha + ^{46}{\\rm Ca}$ is predicted for future experimental tests. The role of nuclear deformations in calculations of the fusion probabilities is analyzed.

  15. Influence of plasma parameters on the absorption coefficient of alpha particles to lower hybrid waves in tokamaks

    SciTech Connect

    Wang, J.; Zhang, X. Yu, L.; Zhao, X.

    2014-12-15

    In tokamaks, fusion generated ? particles may absorb lower hybrid (LH) wave energy, thus reducing the LH current drive efficiency. The absorption coefficient ?{sub ?} of LH waves due to ? particles changing with some typical parameters is calculated in this paper. Results show that ?{sub ?} increases with the parallel refraction index n{sub ?}, while decreases with the frequency of LH waves ? over a wide range. Higher background plasma temperature and toroidal magnetic field will increase the absorption. The absorption coefficient ?{sub ?} increases with n{sub e} when n{sub e} ? 8 × 10{sup 19} m{sup ?3}, while decreases with n{sub e} when n{sub e} becomes larger, and there is a peak value of ?{sub ?} when n{sub e} ? 8 × 10{sup 19} m{sup ?1} for the ITER-like scenario. The influence of spectral broadening in parametric decay instabilities on the absorption coefficient is evaluated. The value of ?{sub ?} with n{sub ?} being 2.5 is almost two times larger than that with n{sub ?} being 2.0 and is even lager in the case of 2.9, which will obviously increase the absorption of the LH power by alpha particles.

  16. Genomic Profiling of a Human Leukemic Monocytic Cell-Line (THP-1) Exposed to Alpha Particle Radiation

    PubMed Central

    Chauhan, Vinita; Howland, Matthew

    2012-01-01

    This study examined alpha (?-) particle radiation effects on global changes in gene expression in human leukemic monocytic cells (THP-1) for the purposes of mining for candidate biomarkers that could be used for the development of a biological assessment tool. THP-1 cells were exposed to ?-particle radiation at a dose range of 0 to 1.5 Gy. Twenty-four hours and three days after exposure gene expression was monitored using microarray technology. A total of 16 genes were dose responsive and classified as early onset due to their expression 24 h after exposure. Forty-eight transcripts were dose responsive and classified as late-onset as they were expressed 72 h after exposure. Among these genes, 6 genes were time and dose responsive and validated further using alternate technology. These transcripts were upregulated and associated with biological processes related to immune function, organelle stability and cell signalling/communication. This panel of genes merits further validation to determine if they are strong candidate biomarkers indicative of ?-particle exposure. PMID:23097634

  17. Nuclear recoil effect in the Lamb shift of light hydrogen-like atoms

    E-print Network

    Yerokhin, V A

    2015-01-01

    We report high-precision calculations of the nuclear recoil effect to the Lamb shift of hydrogen-like atoms to the first order in the electron-nucleus mass ratio and to all orders in the nuclear binding strength parameter $Z\\alpha$. The results are in excellent agreement with the known terms of the $Z\\alpha$ expansion and allow an accurate identification of the nonperturbative higher-order remainder. For hydrogen, the higher-order remainder was found to be much larger than anticipated. This result resolves the long-standing disagreement between the numerical all-order and the analytical $Z\\alpha$-expansion approaches to the recoil effect and completely removes the second-largest theoretical uncertainty in the hydrogen Lamb shift of the $1S$ and $2S$ states.

  18. The {alpha}-particle excited scintillation response of the liquid phase epitaxy grown LuAG:Ce thin films

    SciTech Connect

    Prusa, P.; Cechak, T.; Mares, J. A.; Nikl, M.; Beitlerova, A.; Solovieva, N.; Zorenko, Yu. V.; Gorbenko, V. I.; Tous, J.; Blazek, K.

    2008-01-28

    Liquid phase epitaxy grown Lu{sub 3}Al{sub 5}O{sub 12}:Ce (LuAG:Ce) 20 {mu}m thick films and plate cut from the bulk Czochralski-grown LuAG:Ce crystal were prepared for comparison of photoelectron yield (PhY) and PhY dependence on shaping time (0.5-10 {mu}s). {sup 241}Am ({alpha} particles) was used for excitation. At the 0.5 {mu}s shaping time, the best film shows comparable PhY with the bulk sample. PhY of bulk material increases noticeably more with shaping time than that of the films. Energy resolution of films is better. Influence of Pb{sup 2+} contamination in the films (from the flux) and antisite Lu{sub Al} defect in bulk material is discussed.

  19. Hit rates and radiation doses to nuclei of bone lining cells from alpha-particle-emitting radionuclides

    NASA Technical Reports Server (NTRS)

    Polig, E.; Jee, W. S.; Kruglikov, I. L.

    1992-01-01

    Factors relating the local concentration of a bone-seeking alpha-particle emitter to the mean hit rate have been determined for nuclei of bone lining cells using a Monte Carlo procedure. Cell nuclei were approximated by oblate spheroids with dimensions and location taken from a previous histomorphometric study. The Monte Carlo simulation is applicable for planar and diffuse labels at plane or cylindrical bone surfaces. Additionally, the mean nuclear dose per hit, the dose mean per hit, the mean track segment length and its second moment, the percentage of stoppers, and the frequency distribution of the dose have been determined. Some basic features of the hit statistics for bone lining cells have been outlined, and the consequences of existing standards of radiation protection with regard to the hit frequency to cell nuclei are discussed.

  20. A high-resolution drift chamber for Alpha-particle position measurements 

    E-print Network

    Oliver, Jon Patrick

    1996-01-01

    A drift chamber module with 5 anode wires covering an active region of 9 cm x 76 cm has been built to locate the vertical position of a-particle trajectories to within 295 mm full-width-half-maximum (FWEM) in isobutane at ...

  1. Technical NoteFEASIBILITY STUDIES OF ALPHA-PARTICLE CHANNELING IN MIRROR MACHINES

    E-print Network

    in fusion ash buildup. Plasma instabilities excited by a particles, in turn, heat the back- ground plasma8 is an attractive concept both for fusion reactors and for other plasma applica- tions because of its relative or by otherwise sustaining plasma confinement, thus increasing the effective fusion reactiv- ity. To identify

  2. 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.

  3. Photon Recoil Momentum in Dispersive Media

    SciTech Connect

    Campbell, Gretchen K.; Leanhardt, Aaron E.; Mun, Jongchul; Boyd, Micah; Streed, Erik W.; Ketterle, Wolfgang; Pritchard, David E.

    2005-05-06

    A systematic shift of the photon recoil momentum due to the index of refraction of a dilute gas of atoms has been observed. The recoil frequency was determined with a two-pulse light grating interferometer using near-resonant laser light. The results show that the recoil momentum of atoms caused by the absorption of a photon is n({Dirac_h}/2{pi})k, where n is the index of refraction of the gas and k is the vacuum wave vector of the photon. This systematic effect must be accounted for in high-precision atom interferometry with light gratings.

  4. 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

  5. RADIOACTIVE POSITRON EMITTER PRODUCTION BY ENERGETIC ALPHA PARTICLES IN SOLAR FLARES

    SciTech Connect

    Murphy, R. J.; Kozlovsky, B.; Share, G. H. E-mail: benz@wise.tau.ac.il

    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.

  6. Giant Resonances Observed in Scattering of 96-Mev and 115-Mev Alpha-Particles 

    E-print Network

    Youngblood, David H.; Moss, JM; Rozsa, C. M.; Bronson, J. D.; Bacher, A. D.; Brown, D. R.

    1976-01-01

    . In numer- ous studies of low-lying collective states n inelas- tic scattering has proven to be a valuable spectro- scopic tool." Additionally, e angular distributions are characterized by diffraction structure which 13 994 13 GIANT RESONAN CES OBS... ~ 36, the spectra are characterized by a well- defined broad peak (which we shall call the GQR) at an excitation energy of about 63/A'~' MeV (Fig. 3) sitting on a large n-particle continuum. This peak is not apparent" for targets with A & 32...

  7. Recoil polarimetery in meson photoproduction reactions 

    E-print Network

    Sikora, Mark

    2011-11-23

    A large acceptance polarimeter has been designed to measure recoil polarisation in pseudoscalar (J?=0?) meson photoproduction reactions. The device was installed at the MAMI facility at the Institut für Kernphysik in ...

  8. Recoil effects in multiphoton electron-positron pair creation

    SciTech Connect

    Krajewska, K.; Kaminski, J. Z.

    2010-07-15

    Triply differential probability rates for electron-positron pair creation in laser-nucleus collisions, calculated within the S-matrix approach, are investigated as functions of the nuclear recoil. Pronounced enhancements of differential probability rates of multiphoton pair production are found for a nonzero momentum transfer from the colliding nucleus. The corresponding rates show a very dramatic dependence on the polarization of the laser field impinging on the nucleus; only for a linearly polarized light are the multiphoton rates for electron-positron pair production considerably large. We focus therefore on this case. Our numerical results for different geometries of the reaction particles demonstrate that, for the linearly polarized laser field of an infinite extent (which is a good approximation for femtosecond laser pulses), the pair creation is far more efficient if the nucleus is detected in the direction of the laser-field propagation. The corresponding angular distributions of the created particles show that the high-energy pairs are predominantly produced in the plane spanned by the polarization vector and the laser-field propagation direction, while the low-energy pairs are rather spread around the latter of the two directions. The enhancement of differential probability rates at each energy sector, defined by the four-momentum conservation relation, is observed with varying the energy of the produced particles. The total probability rates of pair production are also evaluated and compared with the corresponding results for the case when one disregards the recoil effect. A tremendous enhancement of the total probability rates of the electron-positron pair creation is observed if one takes into account the nuclear recoil.

  9. Recoil by Auger electrons: Theory and application

    SciTech Connect

    Demekhin, Ph. V.; Scheit, S.; Cederbaum, L. S.

    2009-10-28

    General equations accounting for the molecular dynamics induced by the recoil of a fast Auger electron are presented. The implications of the degree of localization of the molecular orbitals of diatomic molecules involved in the Auger decay are analyzed. It is shown that the direct and exchange terms of the Auger transition matrix element may give rise to opposite signs and hence to opposite directions of the recoil momenta transferred to the nuclear vibrational motion. Consequently, these terms have a different impact on the recoil-induced nuclear dynamics in the final Auger decay state. The developed theory is applied to study the influence of the recoil on the interatomic Coulombic decay (ICD) following the K-LL Auger decay of the Ne dimer. Our calculations illustrate a significant effect of the recoil of nuclei on the computed wave packets propagating on the potential energy curve populated by the Auger decay. The corresponding final states of the Auger process decay further by ICD. We show that the recoil momentum imparted onto the nuclei modifies the computed ICD spectra considerably.

  10. {alpha}-decay properties of the new neutron deficient isotope {sup 212}Pa

    SciTech Connect

    Mitsuoka, S.; Ikezoe, H.; Ikuta, T.; Nagame, Y.; Tsukada, K.; Nishinaka, I.; Oura, Y.; Zhao, Y.L.

    1997-03-01

    The new neutron deficient isotope {sup 212}Pa has been produced in the {sup 182}W({sup 35}Cl,5n) reaction at a beam energy of 182.5 MeV. Evaporation residues have been separated with the JAERI recoil mass separator and identified on the basis of time- and position-correlated {alpha}-decay chains. The {alpha} decay from the ground state of {sup 212}Pa has been observed with an {alpha}-particle energy of 8.270(30) MeV and a half-life of 5.1{sub {minus}1.9}{sup +6.1} ms. {copyright} {ital 1997} {ital The American Physical Society}

  11. 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

  12. 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

  13. Relative Sizes of Ca-40,48 from Scattering of 79 Mev Alpha-Particles 

    E-print Network

    Lerner, G. M.; Hiebert, John C.; Rutledge, L. L.; Papanicolas, C.; Berenstein, A. M.

    1975-01-01

    = 30' is i1lustrated (see text for discussion). 12 THE SCAT TERING~o, &8 Ca F RPME SIzEs pF 781 I.O 4oca 4SC& 5R =O.O fm 48C~ gR =O. I fm 0.06? (b) IO rh I I I ? ) /", 0.05? n O.O4- O IJJ 0.02 O.ol ec m. (deg) il I 30 lO ' 2p... optical model analysis; deduced rDls matter x'adli. I. INTRODUCTION U(r. ) =(A?+iA,) p(r)V?,,?(r-rgd7 (la) or (((r, )=(X, ?(5;~ p(r))'.?(r?|,)dv, ((b) 6' where A?and A, (or 5;) are empirical functions of 1: (the n particle energy), p(r...

  14. 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.

  15. Measurement of scintillation efficiency for nuclear recoils in liquid argon

    E-print Network

    D. Gastler; E. Kearns; A. Hime; L. C. Stonehill; S. Seibert; J. Klein; W. H. Lippincott; D. N. McKinsey; J. A. Nikkel

    2012-05-08

    The scintillation light yield of liquid argon from nuclear recoils relative to electronic recoils has been measured as a function of recoil energy from 10 keVr up to 250 keVr. The scintillation efficiency, defined as the ratio of the nuclear recoil scintillation response to the electronic recoil response, is 0.25 \\pm 0.01 + 0.01(correlated) above 20 keVr.

  16. 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

  17. 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.

  18. Gold Coated Lanthanide Phosphate Nanoparticles for Targeted Alpha Generator Radiotherapy

    SciTech Connect

    McLaughlin, Mark F; Woodward, Jonathan; Boll, Rose Ann; Wall, Jonathan; Rondinone, Adam Justin; Kennel, Steve J; Mirzadeh, Saed; Robertson, David J.

    2013-01-01

    Targeted radiotherapies maximize cytotoxicty to cancer cells. In vivo generators such as 225Ac, which emits four particles in its decay chain, can significantly amplify the radiation dose delivered to the target site. However, renal dose from unbound 213Bi escaping during the decay process limits the dose of 225Ac that can be administered. Traditional chelating moieties are unable to sequester the radioactive daughters because of the high recoil energy from alpha particle emission. To counter this, we demonstrate that an engineered multilayered nanoparticle-antibody conjugate can both deliver radiation and contain the decay daughters of the in vivo -generator 225Ac while targeting biologically relevant receptors. These multi-shell nanoparticles combine the radiation resistance of crystalline lanthanide phosphate to encapsulate and contain 225Ac and its radioactive decay daughters, the magnetic properties of gadolinium phosphate for easy separation, and established surface chemistry of gold for attachment of nanoparticles to targeting antibodies.

  19. 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.

  20. 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.

  1. 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.

  2. Effects of Alpha Particle and Proton Beam Irradiation as Putative Cross-Talk between A549 Cancer Cells and the Endothelial Cells in a Co-Culture System

    PubMed Central

    Riquier, Hélène; Abel, Denis; Wera, Anne-Catherine; Heuskin, Anne-Catherine; Genard, Géraldine; Lucas, Stéphane; Michiels, Carine

    2015-01-01

    Background: High-LET ion irradiation is being more and more often used to control tumors in patients. Given that tumors are now considered as complex organs composed of multiple cell types that can influence radiosensitivity, we investigated the effects of proton and alpha particle irradiation on the possible radioprotective cross-talk between cancer and endothelial cells. Materials and Methods: We designed new irradiation chambers that allow co-culture study of cells irradiated with a particle beam. A549 lung carcinoma cells and endothelial cells (EC) were exposed to 1.5 Gy of proton beam or 1 and 2 Gy of alpha particles. Cell responses were studied by clonogenic assays and cell cycle was analyzed by flow cytometry. Gene expression studies were performed using Taqman low density array and by RT-qPCR. Results: A549 cells and EC displayed similar survival fraction and they had similar cell cycle distribution when irradiated alone or in co-culture. Both types of irradiation induced the overexpression of genes involved in cell growth, inflammation and angiogenesis. Conclusions: We set up new irradiation chamber in which two cell types were irradiated together with a particle beam. We could not show that tumor cells and endothelial cells were able to protect each other from particle irradiation. Gene expression changes were observed after particle irradiation that could suggest a possible radioprotective inter-cellular communication between the two cell types but further investigations are needed to confirm these results. PMID:25794049

  3. Design of an alpha-particle counting system at a defined solid angle at Turkish atomic energy authority-Sarayköy nuclear research and training center (TAEK-SANAEM)

    NASA Astrophysics Data System (ADS)

    Seferino?lu, Meryem; Yeltepe, Emin

    2015-12-01

    The design details of an alpha-particle counting set-up at a defined solid angle (ACS-DSA) constructed in Radionuclide Metrology Department at TAEK-SANAEM for use in the primary standardization of radioactive solutions and determination of nuclear decay data of alpha-particle emitters is presented. The counting system is designed such that the solid angle is very well-defined and directly traceable to the national standards. The design involves mechanical construction of different parts like the source chamber, various coaxial flanges, and circular diaphragms in front of the passivated implanted planar silicon (PIPS®) detector, distance tubes, a digital caliper and a sliding piston to allow for different measurement configurations. All geometric configurations are easily changeable and characterisable with high accuracy which facilitates the solid angle calculation. A mixed alpha source was counted to check performance of assembled ACS-DSA system and good energy resolution and low peak tailing in the alpha energy spectrum was observed for small diaphragm apertures and far source-to-detector geometries.

  4. Cavitation Bubble Nucleation by Energetic Particles

    SciTech Connect

    West, C.D.

    1998-12-01

    In the early sixties, experimental measurements using a bubble chamber confirmed quantitatively the thermal spike theory of bubble nucleation by energetic particles: the energy of the slow, heavy alpha decay recoils used in those experiments matched the calculated bubble nucleation energy to within a few percent. It was a triumph, but was soon to be followed by a puzzle. Within a couple of years, experiments on similar liquids, but well below their normal boiling points, placed under tensile stress showed that the calculated bubble nucleation energy was an order of magnitude less than the recoil energy. Why should the theory work so well in the one case and so badly in the other? How did the liquid, or the recoil particle, "know" the difference between the two experiments? Another mathematical model of the same physical process, introduced in 1967, showed qualitatively why different analyses would be needed for liquids with high and low vapor pressures under positive or negative pressures. But, the quantitative agreement between the calculated nucleation energy and the recoil energy was still poor--the former being smaller by a factor of two to three. In this report, the 1967 analysis is extended and refined: the qualitative understanding of the difference between positive and negative pressure nucleation, "boiling" and "cavitation" respectively, is retained, and agreement between the negative pressure calculated to be needed for nucleation and the energy calculated to be available is much improved. A plot of the calculated negative pressure needed to induce bubble formation against the measured value now has a slope of 1.0, although there is still considerable scatter in the individual points.

  5. ITER Plasma at Ion Cyclotron Frequency Domain: The Fusion Alpha Particles Diagnostics Based on the Stimulated Raman Scattering of Fast Magnetosonic Wave off High Harmonic Ion Bernstein Modes

    NASA Astrophysics Data System (ADS)

    Stefan, V. Alexander

    2014-10-01

    A novel method for alpha particle diagnostics is proposed. The theory of stimulated Raman scattering, SRS, of the fast wave and ion Bernstein mode, IBM, turbulence in multi-ion species plasmas, (Stefan University Press, La Jolla, CA, 2008). is utilized for the diagnostics of fast ions, (4)He (+2), in ITER plasmas. Nonlinear Landau damping of the IBM on fast ions near the plasma edge leads to the space-time changes in the turbulence level, (inverse alpha particle channeling). The space-time monitoring of the IBM turbulence via the SRS techniques may prove efficient for the real time study of the fast ion velocity distribution function, spatial distribution, and transport. Supported by Nikola Tesla Labs., La Jolla, CA 92037.

  6. Energy transport via quasiparticle and phonon diffusion in superheated superconducting granule detectors after nuclear recoils

    NASA Astrophysics Data System (ADS)

    Gabutti, A.

    1995-04-01

    The energy transport via thermal diffusion inside superheated superconducting granules (SSG) after nuclear recoils is discussed. The decay towards equilibrium of the initial disturbance is described by a set of coupled heat-flow equations for the effective quasiparticle and phonon temperatures. The solution is carried out analytically for a point source located anywhere inside the superconducting granule with the initial energy distributed in both quasiparticle and phonon systems. The calculated sensitivity to nuclear recoils and the decay in time between interaction and phase transition are compared with irradiation measurements performed on Sn and Zn granules. The derived expressions for the quasiparticle and phonon temperatures are useful to predict the sensitivity of SSG detectors to nuclear recoils produced in dark matter particle or neutrino interactions.

  7. Determination of primary energy in nucleus-nucleus collisions and the high P(sub)T tail of alpha-particles

    NASA Technical Reports Server (NTRS)

    Freier, P. S.; Atwater, T. W.

    1985-01-01

    A determination of primary energy is required in order to study the energy dependence of meson multiplicity in A-A collisions in cosmic rays. Various procedures which estimate the energy of a primary nucleus from its interaction were investigated. An average of two methods were used, one using the pions and wounded protons and the other using spectator protons and alpha particles. The high P sub T tail observed for Z = 2 fragments requires a modification of the latter method.

  8. Utilization of wavelength-shifting fibers coupled to ZnS(Ag) and plastic scintillator for simultaneous detection of alpha/beta particles

    NASA Astrophysics Data System (ADS)

    Ifergan, Y.; Dadon, S.; Israelashvili, I.; Osovizky, A.; Gonen, E.; Yehuda-Zada, Y.; Smadja, D.; Knafo, Y.; Ginzburg, D.; Kadmon, Y.; Cohen, Y.; Mazor, T.

    2015-06-01

    Low level radioactive surface contamination measurements require lightweight, large area and high efficiency detector. In most existing scintillation detectors there is a tradeoff between effective area and scintillation light collection. By using wavelength shifting (WLS) fibers the scintillation light may be collected efficiently also in a large area detector. In this study, WLS fibers were coupled to a beta sensitive plastic scintillator layer and to a alpha sensitive silver-activated zinc sulfide ZnS(Ag) layer for detecting both alpha and beta particles. The WLS fibers collect the scintillation light from the whole detector and transfer it to a single PMT. This first prototype unique configuration enables monitoring radioactive contaminated surfaces by both sides of the detector and provides high gamma rejection. In this paper, the detector structure, as well as the detector's measured linear response, will be described. The measured detection efficiency of 238Pu alpha particles (5.5 MeV) is ~63%. The measured detection efficiency for beta particles is ~89% for 90Sr-90Y (average energy of 195.8 keV, 934.8 keV), ~50% for 36Cl (average energy of 251.3 keV), and 35% for 137Cs (average energy of 156.8 keV).

  9. Engineered Modular Recombinant Transporters: Application of New Platform for Targeted Radiotherapeutic Agents to {alpha}-Particle Emitting {sup 211}At

    SciTech Connect

    Rosenkranz, Andrey A.; Vaidyanathan, Ganesan; Pozzi, Oscar R.; Lunin, Vladimir G.; Zalutsky, Michael R. Sobolev, Alexander S.

    2008-09-01

    Purpose: To generate and evaluate a modular recombinant transporter (MRT) for targeting {sup 211}At to cancer cells overexpressing the epidermal growth factor receptor (EGFR). Methods and Materials: The MRT was produced with four functional modules: (1) human epidermal growth factor as the internalizable ligand, (2) the optimized nuclear localization sequence of simian vacuolating virus 40 (SV40) large T-antigen, (3) a translocation domain of diphtheria toxin as an endosomolytic module, and (4) the Escherichia coli hemoglobin-like protein (HMP) as a carrier module. MRT was labeled using N-succinimidyl 3-[{sup 211}At]astato-5-guanidinomethylbenzoate (SAGMB), its {sup 125}I analogue SGMIB, or with {sup 131}I using Iodogen. Binding, internalization, and clonogenic assays were performed with EGFR-expressing A431, D247 MG, and U87MG.wtEGFR human cancer cell lines. Results: The affinity of SGMIB-MRT binding to A431 cells, determined by Scatchard analysis, was 22 nM, comparable to that measured before labeling. The binding of SGMIB-MRT and its internalization by A431 cancer cells was 96% and 99% EGFR specific, respectively. Paired label assays demonstrated that compared with Iodogen-labeled MRT, SGMIB-MRT and SAGMB-MRT exhibited more than threefold greater peak levels and durations of intracellular retention of activity. SAGMB-MRT was 10-20 times more cytotoxic than [{sup 211}At]astatide for all three cell lines. Conclusion: The results of this study have demonstrated the initial proof of principle for the MRT approach for designing targeted {alpha}-particle emitting radiotherapeutic agents. The high cytotoxicity of SAGMB-MRT for cancer cells overexpressing EGFR suggests that this {sup 211}At-labeled conjugate has promise for the treatment of malignancies, such as glioma, which overexpress this receptor.

  10. 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.

  11. 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;

  12. Measured Nuclear Recoil Discrimination for HPGS, a Proposed Ton-Scale Dark Matte r Search in Room Temperature Gas

    NASA Astrophysics Data System (ADS)

    Martin, C.; Barton, D.; Dion, M. P.; Esterline, J. H.; Howell, C. R.; Martoff, C. J.; Smith, P. F.; Tornow, W.

    2009-05-01

    The HPGS dark matter proposal is for a simple, room-temperature, ton-scale, 5-10 bar gas scintillation array with nuclear recoil discrimination by pulse-shape, aided by electric fields to suppress wall events. The first experimental confirmation of nuclear recoil discrimination by Xe gas scintillation pulse shape is reported here. Pulse shapes for ?- and x-rays, neutrons, and ? particles were measured using highly purified Xe gas at 1-6 bar with a UV-sensitive photomultiplier. Nuclear recoil and ? pulses were dominated by recombination scintillation with time constant 250 ns, while gamma and x-ray scintillation was completely contained within 15 ns. We will present detailed comparison of our nuclear recoil pulse shape discrimination to liquid Xe, and discuss the outlook for simpler and lower cost room temperature ton-scale dark matter detectors. (We heartily thank A. Bolotnikov for access to high-purity Xe in his lab at Brookhaven National Laboratory.)

  13. Ab initio alpha-alpha scattering.

    PubMed

    Elhatisari, Serdar; Lee, Dean; Rupak, Gautam; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A; Luu, Thomas; Meißner, Ulf-G

    2015-12-01

    Processes such as the scattering of alpha particles ((4)He), the triple-alpha reaction, and alpha capture play a major role in stellar nucleosynthesis. In particular, alpha capture on carbon determines the ratio of carbon to oxygen during helium burning, and affects subsequent carbon, neon, oxygen, and silicon burning stages. It also substantially affects models of thermonuclear type Ia supernovae, owing to carbon detonation in accreting carbon-oxygen white-dwarf stars. In these reactions, the accurate calculation of the elastic scattering of alpha particles and alpha-like nuclei--nuclei with even and equal numbers of protons and neutrons--is important for understanding background and resonant scattering contributions. First-principles calculations of processes involving alpha particles and alpha-like nuclei have so far been impractical, owing to the exponential growth of the number of computational operations with the number of particles. Here we describe an ab initio calculation of alpha-alpha scattering that uses lattice Monte Carlo simulations. We use lattice effective field theory to describe the low-energy interactions of protons and neutrons, and apply a technique called the 'adiabatic projection method' to reduce the eight-body system to a two-cluster system. We take advantage of the computational efficiency and the more favourable scaling with system size of auxiliary-field Monte Carlo simulations to compute an ab initio effective Hamiltonian for the two clusters. We find promising agreement between lattice results and experimental phase shifts for s-wave and d-wave scattering. The approximately quadratic scaling of computational operations with particle number suggests that it should be possible to compute alpha scattering and capture on carbon and oxygen in the near future. The methods described here can be applied to ultracold atomic few-body systems as well as to hadronic systems using lattice quantum chromodynamics to describe the interactions of quarks and gluons. PMID:26632590

  14. Proton recoil scintillator neutron rem meter

    DOEpatents

    Olsher, Richard H. (Los Alamos, NM); Seagraves, David T. (Los Alamos, NM)

    2003-01-01

    A neutron rem meter utilizing proton recoil and thermal neutron scintillators to provide neutron detection and dose measurement. In using both fast scintillators and a thermal neutron scintillator the meter provides a wide range of sensitivity, uniform directional response, and uniform dose response. The scintillators output light to a photomultiplier tube that produces an electrical signal to an external neutron counter.

  15. Cross sections for {alpha}-particle induced reactions on {sup 115,116}Sn around the Coulomb barrier

    SciTech Connect

    Filipescu, D.; Avrigeanu, V.; Glodariu, T.; Mihai, C.; Bucurescu, D.; Ivascu, M.; Cata-Danil, I.; Stroe, L.; Deleanu, D.; Ghita, D. G.; Marginean, N.; Marginean, R.; Negret, A.; Pascu, S.; Sava, T.; Suliman, G.; Zamfir, N. V.; Sima, O.; Cata-Danil, G.

    2011-06-15

    The cross sections of the {sup 115}Sn({alpha},{gamma}){sup 119}Te, {sup 115}Sn({alpha},n){sup 118}Te, and {sup 116}Sn({alpha},n){sup 119}Te reactions (both on ground and isomeric states) have been measured at effective center-of-mass energies from 9.3 to 14.8 MeV. During a first experiment, enriched self-supporting {sup 115}Sn (51.2%) + {sup 116}Sn (24.4%) foils were bombarded with an {alpha} beam delivered by the Bucharest IFIN-HH Tandem Accelerator. In a second experiment, a highly enriched {sup 116}Sn target was irradiated in order to disentangle the experimental cross section contributions due to {sup 115}Sn({alpha},{gamma}){sup 119}Te and {sup 115}Sn({alpha},n){sup 118}Te reactions obtained in the first measurement. The beam-induced activity was measured with two large volume HPGe detectors in close geometry. The experimental results were compared with theoretical predictions obtained in the framework of the statistical model.

  16. Evaluation of an ITER compatible, thin foil Faraday collector as a lost alpha particle diagnostic for high yield D{endash}T fusion plasmas

    SciTech Connect

    Loughlin, M.J.; Cecil, F.E.; Hone, M.; Jarvis, O.N.; Medley, S.S.; Roquemore, A.L.; Sadler, G.J.; van Belle, P.; Whitfield, G.

    1997-01-01

    We have examined the concept of a thin foil Faraday collector as a lost alpha particle detector capable of operating under ITER-like conditions. A prototype detector consisting of a single set of four 2.5 {mu}m Ni foils was installed on the JET first wall and operated during a variety of deuterium plasma conditions during the 1995 JET run period. Although there was no significant production of alpha particles during these plasmas, the prototype demonstrated the expected resistance to the high temperature and x-ray backgrounds, as well as moderate neutron and gamma ray backgrounds characteristic of these plasmas. In addition, this prototype showed no significant response to neutral beam, rf, or lower hybrid plasma heating. The device did pick up a low level signal when neutral beams were injected simultaneously with heavy gas puffing. Strong intermittent correlations {ital were} seen with excursions in the H{alpha} edge brightness signal. In addition, the detector produced a significant signal in response to a roughly 250 ms disruption precursor. A similar prototype detector was installed immediately {ital outside} the Tokamak Fusion Test Reactor vacuum vessel during the 1994 D{endash}T run period to test the expected insensitivity to neutron backgrounds. No signal was seen above background during D{endash}T plasmas for which the fast neutron production was in excess of 2{times}10{sup 18} n/s. {copyright} {ital 1997 American Institute of Physics.}

  17. Development of Bubble Chambers With Enhanced Stability and Sensitivity to Low-Energy Nuclear Recoils

    E-print Network

    W. J. Bolte; J. I. Collar; M. Crisler; J. Hall; D. Holmgren; D. Nakazawa; B. Odom; K. O'Sullivan; R. Plunkett; E. Ramberg; A. Raskin; A. Sonnenschein; J. D. Vieira

    2005-03-17

    The viability of using a Bubble Chamber for rare event searches and in particular for the detection of dark matter particle candidates is considered. Techniques leading to the deactivation of inhomogeneous nucleation centers and subsequent enhanced stability in such a detector are described. Results from prototype trials indicate that sensitivity to low-energy nuclear recoils like those expected from Weakly Interacting Massive Particles can be obtained in conditions of near total insensitivity to minimum ionizing backgrounds. An understanding of the response of superheated heavy refrigerants to these recoils is demonstrated within the context of existing theoretical models. We comment on the prospects for the detection of supersymmetric dark matter particles with a large $CF_{3}I$ chamber.

  18. Development of bubble chambers with enhanced stability and sensitivity to low-energy nuclear recoils

    SciTech Connect

    Bolte, W.J.; Collar, Juan 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.; /Chicago U., EFI /KICP, Chicago /Fermilab

    2005-03-01

    The viability of using a Bubble Chamber for rare event searches and in particular for the detection of dark matter particle candidates is considered. Techniques leading to the deactivation of inhomogeneous nucleation centers and subsequent enhanced stability in such a detector are described. Results from prototype trials indicate that sensitivity to low-energy nuclear recoils like those expected from Weakly Interacting Massive Particles can be obtained in conditions of near total insensitivity to minimum ionizing backgrounds. An understanding of the response of superheated heavy refrigerants to these recoils is demonstrated within the context of existing theoretical models. We comment on the prospects for the detection of supersymmetric dark matter particles with a large CF{sub 3}I chamber.

  19. Ionization and scintillation of nuclear recoils in gaseous xenon

    NASA Astrophysics Data System (ADS)

    Renner, J.; Gehman, V. M.; Goldschmidt, A.; Matis, H. S.; Miller, T.; Nakajima, Y.; Nygren, D.; Oliveira, C. A. B.; Shuman, D.; Álvarez, V.; Borges, F. I. G.; Cárcel, S.; Castel, J.; Cebrián, S.; Cervera, A.; Conde, C. A. N.; Dafni, T.; Dias, T. H. V. T.; Díaz, J.; Esteve, R.; Evtoukhovitch, P.; Fernandes, L. M. P.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Gil, A.; Gómez, H.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Hauptman, J.; Hernando Morata, J. A.; Herrera, D. C.; Iguaz, F. J.; 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.; Martínez, A.; Moiseenko, A.; Monrabal, F.; Monserrate, M.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Natal da Luz, H.; Navarro, G.; Nebot-Guinot, M.; Palma, R.; Pérez, J.; Pérez Aparicio, J. L.; Ripoll, L.; Rodríguez, A.; Rodríguez, J.; Santos, F. P.; dos Santos, J. M. F.; Seguí, L.; Serra, L.; Simón, A.; Sofka, C.; Sorel, M.; Toledo, J. F.; Tomás, A.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Villar, J. A.; Webb, R. C.; White, J.; Yahlali, N.

    2015-09-01

    Ionization and scintillation produced by nuclear recoils in gaseous xenon at approximately 14 bar have been simultaneously observed in an electroluminescent time projection chamber. Neutrons from radioisotope ?-Be neutron sources were used to induce xenon nuclear recoils, and the observed recoil spectra were compared to a detailed Monte Carlo employing estimated ionization and scintillation yields for nuclear recoils. The ability to discriminate between electronic and nuclear recoils using the ratio of ionization to primary scintillation is demonstrated. These results encourage further investigation on the use of xenon in the gas phase as a detector medium in dark matter direct detection experiments.

  20. The scintillation and ionization yield of liquid xenon for nuclear recoils

    E-print Network

    P. Sorensen; A. Manzur; C. E. Dahl; J. Angle; E. Aprile; F. Arneodo; L. Baudis; A. Bernstein; A. Bolozdynya; P. Brusov; L. C. C. Coelho; L. DeViveiros; A. D. Ferella; L. M. P. Fernandes; S. Fiorucci; R. J. Gaitskell; K. L. Giboni; R. Gomez; R. Hasty; L. Kastens; J. Kwong; J. A. M. Lopes; N. Madden; A. Manalaysay; D. N. McKinsey; M. E. Monzani; K. Ni; U. Oberlack; J. Orboeck; G. Plante; R. Santorelli; J. M. F. dos Santos; P. Shagin; T. Shutt; S. Schulte; C. Winant; M. Yamashita; for the XENON10 Collaboration

    2008-12-31

    XENON10 is an experiment designed to directly detect particle dark matter. It is a dual phase (liquid/gas) xenon time-projection chamber with 3D position imaging. Particle interactions generate a primary scintillation signal (S1) and ionization signal (S2), which are both functions of the deposited recoil energy and the incident particle type. We present a new precision measurement of the relative scintillation yield \\leff and the absolute ionization yield Q_y, for nuclear recoils in xenon. A dark matter particle is expected to deposit energy by scattering from a xenon nucleus. Knowledge of \\leff is therefore crucial for establishing the energy threshold of the experiment; this in turn determines the sensitivity to particle dark matter. Our \\leff measurement is in agreement with recent theoretical predictions above 15 keV nuclear recoil energy, and the energy threshold of the measurement is 4 keV. A knowledge of the ionization yield \\Qy is necessary to establish the trigger threshold of the experiment. The ionization yield \\Qy is measured in two ways, both in agreement with previous measurements and with a factor of 10 lower energy threshold.

  1. 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.; Sudar, S.

    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.

  2. A Recoil Mass Spectrometer for the HHIRF facility

    SciTech Connect

    Cole, J.D. ); Cormier, T.M. ); Hamilton, J.H. . Dept. of Physics and Astronomy)

    1989-01-01

    A Recoil Mass Spectrometer (RMS) is to be built that will carry out a broad research program in heavy-ion science. The RMS will make possible the study of otherwise inaccessible exotic nuclei. Careful attention has been given to match the RMS to all the beams available from the HHIRF accelerators, including those beams with the highest energy, as well as massive particles for use in inverse reactions. The RMS is to be a momentum achromat followed by a split electric-dipole mass spectrometer of the type operating at NSRL at the University of Rochester. The RMS is essential for many of the proposed experiments on short-lived and/or low cross-section products. The spectrometer design is discussed, with examples and comparisons with other spectrometers given. Detector arrays to be used with the RMS are also discussed. 21 refs., 4 figs., 1 tab.

  3. Skyrmion recoil in pion-nucleon scattering

    SciTech Connect

    Hughes, J. Physics Department, University of California at Davis, Davis, California 95616 ); Mathews, G.J. )

    1992-08-01

    We calculate the lowest-order recoil corrections to the pion-nucleon scattering matrix in the SU(2) Skyrme model. The corrections result from a direct semiclassical evaluation of path-integral expressions for relevant finite-time transition amplitudes. The {ital S} matrix for pion-nucleon scattering is extracted from these amplitudes by using a configuration-space representation for the asymptotic nucleons; the quanta are treated just as in the vacuum sector. The recoil corrections result from the Skyrmion freely translating between initial and final positions, and are relevant to a kinematical regime opposite to that where the impulse approximation is valid. The form of the corrections is model independent, unchanged for any chiral model with hedgehog solitary wave solutions. Remarkably, new lowest-lying resonances emerge in the {ital p} channels, whereas the {ital s} and {ital d} waves are not noticeably improved.

  4. Experiments with recoil ions and other considerations

    SciTech Connect

    Cocke, C.L.

    1987-01-01

    Some opportunities in collisions physics with slow, multiply charged ions are addressed. A distinction between inner and outer shell collisions is drawn. The applicability of recoil ion sources to outer shell collision systems is discussed, with emphasis on the quality of the beam desired. An example of an inner shell collision is discussed, and the usefulness of not pushing the collision energy too low is pointed out. 13 refs., 14 figs.

  5. 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.

  6. 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.

  7. Imprints of recoiling massive black-holes on the hot gas of early type galaxies

    E-print Network

    B. Devecchi; E. Rasia; M. Dotti; M. Volonteri; M. Colpi

    2008-12-11

    Anisotropic gravitational radiation from a coalescing black hole binary is known to impart recoil velocities of up to ~1000 km/s to the remnant black hole. In this context, we study the motion of a recoiling black hole inside a galaxy modelled as an Hernquist sphere, and the signature that the hole imprints on the hot gas, using N-body/SPH simulations. Ejection of the black hole results in a sudden expansion of the gas ending with the formation of a gaseous core, similarly to what is seen for the stars. A cometary tail of particles bound to the black hole is initially released along its trail. As the black hole moves on a return orbit, a nearly spherical swarm of hot gaseous particles forms at every apocentre: this feature can live up to ~ 100 Myr. If the recoil velocity exceeds the sound speed initially, the black hole shocks the gas in the form of a Mach cone in density near each super-sonic pericentric passage. We find that the X-ray fingerprint of a recoiling black hole can be detected in Chandra X-ray maps out to a distance of Virgo. For exceptionally massive black holes the Mach cone and the wakes could be observed out to a few hundred of Mpc. Detection of the Mach cone is found to become of twofold importance: i) as a probe of high-velocity recoils and ii) as an assessment of the scatter of the mass-sigma relation at large black hole masses.

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

    E-print Network

    Yu, Peter K.N.

    from non-targeted cells. These provided evidence for the bystander effect. Ó 2007 Elsevier B.V. All-targeted) cells. The latter are known as bystander effects which occur when an irradiated cell communicates for the depen- dence of DNA strand breaks on the LET or for the presence of bystander effects, accurate alpha

  9. Relativistic nuclear recoil corrections to the energy levels of hydrogen-like and high $Z$ lithium like atoms in all orders in $?Z$

    E-print Network

    A. N. Artemyev; V. M. Shabaev; V. A. Yerokhin

    1995-06-14

    The relativistic nuclear recoil corrections to the energy levels of low-laying states of hydrogen-like and high $Z$ lithium-like atoms in all orders in $\\alpha Z$ are calculated. The calculations are carried out using the B-spline method for the Dirac equation. For low $Z$ the results of the calculation are in good agreement with the $\\alpha Z$ -expansion results. It is found that the nuclear recoil contribution, additional to the Salpeter's one, to the Lamb shift ($n=2$) of hydrogen is $-1.32(6)\\,kHz$. The total nuclear recoil correction to the energy of the $(1s)^{2}2p_{\\frac{1}{2}}-(1s)^{2}2s$ transition in lithium-like uranium constitutes $-0.07\\,eV$ and is largely made up of QED contributions.

  10. Elementary Analysis of a Cometary Surface - the Alpha Particle X-Ray Spectrometer APXS on the Rosetta Mission to Comet 67P/CHURYUMOV-GERASIMENKO

    NASA Astrophysics Data System (ADS)

    Schmanke, Dirk; Economou, Thanasis; Brueckner, Johannes; Gellert, Ralf; Rodionov, Daniel; Klingelhoefer, Goestar; Girones Lopez, Jordi; Uston, Lionel D.

    After a 10 years cruise the Rosetta probe will reach its final target in the middle of this year, 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 examination of the comet the lander Philae will be separated to land on the comet surface. It will start immediately examining the landing site with its scientific payload. A 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 its changes during the journey of the comet towards the sun. APXS is a combination of two spectrometers in one single instrument, being low in mass and power consumption. It will irradiate the cometary surface with 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. During the long duration travel to the comet checkouts and software updates of the Rosetta probe and its payload were performed at regular intervals. In recent 3 years the solar powered Rosetta probe had to pass a hibernation phase because of a long passage far away from the sun. After the successful wakeup in January 2014 an extensive test phase of all instruments and subsystems has to be performed, including the APXS. After the landing on the comet an intense long measurement phase of all instruments is planned, the First Science Sequence (FSS). It will be followed by a long term science phase (LTS), determined by periodical changes between measurements and forced breaks to recharge the lander batteries. During these operations the Rosetta probe will escort the comet and the lander along the comets trajectory around the sun. As long as possible APXS and the other instruments will continue to repeat their measurements to monitor the changes and rising activity of the comet. This will shed light on state, composition, evolution and the origin of comets and the solar system. Acknowledgements: This project is funded by the German Space Agency DLR under contracts 50 QP 0404 and 50 QP 0902. References: G. Klingelhöfer, J. Brückner, C. d'Uston, R. Gellert, and R. Rieder, The Rosetta Alpha Particle X-ray Spectrometer (APXS), Space Science Reviews, Vol.128 (2007) 383-396; doi:10.1007/s11214-006-9137-3

  11. 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

  12. Scintillation of liquid neon from electronic and nuclear recoils

    E-print Network

    J. A. Nikkel; R. Hasty; W. H. Lippincott; D. N. McKinsey

    2006-12-04

    We have measured the time dependence of scintillation light from electronic and nuclear recoils in liquid neon, finding a slow time constant of 15.4+-0.2 us. Pulse shape discrimination is investigated as a means of identifying event type in liquid neon. Finally, the nuclear recoil scintillation efficiency is measured to be 0.26+-0.03 for 387 keV nuclear recoils.

  13. 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.

  14. Thermal recoil force, telemetry, and the Pioneer anomaly

    SciTech Connect

    Toth, Viktor T.; Turyshev, Slava G.

    2009-02-15

    Precision navigation of spacecraft requires accurate knowledge of small forces, including the recoil force due to anisotropies of thermal radiation emitted by spacecraft systems. We develop a formalism to derive the thermal recoil force from the basic principles of radiative heat exchange and energy-momentum conservation. The thermal power emitted by the spacecraft can be computed from engineering data obtained from flight telemetry, which yields a practical approach to incorporate the thermal recoil force into precision spacecraft navigation. Alternatively, orbit determination can be used to estimate the contribution of the thermal recoil force. We apply this approach to the Pioneer anomaly using a simulated Pioneer 10 Doppler data set.

  15. Site-specific recoil diffraction of backscattered electrons in crystals.

    PubMed

    Winkelmann, Aimo; Vos, Maarten

    2011-02-25

    A novel diffraction effect in high-energy electron backscattering is demonstrated: the formation of element-specific diffraction patterns via nuclear recoil. For sapphire (Al(2)O(3)), the difference in recoil energy allows us to determine if an electron scattered from aluminum or from oxygen. The angular electron distribution obtained in such measurements is a strong function of the recoiling lattice site. These element-specific recoil diffraction features are explained using the dynamical theory of electron diffraction. Our observations open up new possibilities for local, element-resolved crystallographic analysis using quasielastically backscattered electrons in scanning electron microscopy. PMID:21405583

  16. Site-Specific Recoil Diffraction of Backscattered Electrons in Crystals

    NASA Astrophysics Data System (ADS)

    Winkelmann, Aimo; Vos, Maarten

    2011-02-01

    A novel diffraction effect in high-energy electron backscattering is demonstrated: the formation of element-specific diffraction patterns via nuclear recoil. For sapphire (Al2O3), the difference in recoil energy allows us to determine if an electron scattered from aluminum or from oxygen. The angular electron distribution obtained in such measurements is a strong function of the recoiling lattice site. These element-specific recoil diffraction features are explained using the dynamical theory of electron diffraction. Our observations open up new possibilities for local, element-resolved crystallographic analysis using quasielastically backscattered electrons in scanning electron microscopy.

  17. 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.

  18. Hygroscopicity of particles generated from photooxidation of alpha-pinene under different oxidation conditions in the presence of sulfate seed aerosols.

    PubMed

    Chu, Biwu; Wang, Kun; Takekawa, Hideto; Li, Junhua; Zhou, Wei; Jiang, Jingkun; Ma, Qinxing; He, Hong; Hao, Jiming

    2014-01-01

    Smog chamber experiments were conducted to investigate the hygroscopicity of particles generated from photooxidation of alpha-pinene/NO(x) with different sulfate seed aerosols or oxidation conditions. Hygroscopicity of particles was measured by a tandem differential mobility analyzer (TDMA) in terms of hygroscopic growth factor (Gf), with a relative humidity of 85%. With sulfate seed aerosols present, Gf of the aerosols decreased very fast before notable secondary organic aerosols (SOA) formation was observed, indicating a heterogeneous process between inorganic seeds and organic products might take place as soon as oxidation begins, rather than only happening after gas-aerosol partition of organic products starts. The final SOA-coated sulfate particles had similar or lower Gf than seed-free SOA. The hygroscopicity of the final particles was not dependent on the thickness but on the hygroscopicity properties of the SOA, which were influenced by the initial sulfate seed particles. In the two designed aging processes, Gf of the particles increased more significantly with introduction of OH radical than with ozone. However, the hygroscopicity of SOA was very low even after a long time of aging, implying that either SOA aging in the chamber was very slow or the Gf of SOA did not change significantly in aging. Using an aerosol composition speciation monitor (ACSM) and matrix factorization (PMF) method, two factors for the components of SOA were identified, but the correlation between SOA hygroscopicity and the proportion of the more highly oxidized factor could be either positive or negative depending on the speciation of seed aerosols present. PMID:24649698

  19. A gas ionisation detector in the axial (Bragg) geometry used for the time-of-flight elastic recoil detection analysis.

    PubMed

    Siketi?, Zdravko; Skukan, Natko; Bogdanovi? Radovi?, Iva

    2015-08-01

    In this paper, time-of-flight elastic recoil detection analysis spectrometer with a newly constructed gas ionization detector for energy detection is presented. The detector is designed in the axial (Bragg) geometry with a 3 × 3 array of 50 nm thick Si3N4 membranes as an entrance window. 40 mbar isobutane gas was sufficient to stop a 30 MeV primary iodine beam as well as all recoils in the detector volume. Spectrometer and detector performances were determined showing significant improvement in the mass and energy resolution, respectively, comparing to the spectrometer with a standard silicon particle detector for an energy measurement. PMID:26329175

  20. A gas ionisation detector in the axial (Bragg) geometry used for the time-of-flight elastic recoil detection analysis

    NASA Astrophysics Data System (ADS)

    Siketi?, Zdravko; Skukan, Natko; Bogdanovi? Radovi?, Iva

    2015-08-01

    In this paper, time-of-flight elastic recoil detection analysis spectrometer with a newly constructed gas ionization detector for energy detection is presented. The detector is designed in the axial (Bragg) geometry with a 3 × 3 array of 50 nm thick Si3N4 membranes as an entrance window. 40 mbar isobutane gas was sufficient to stop a 30 MeV primary iodine beam as well as all recoils in the detector volume. Spectrometer and detector performances were determined showing significant improvement in the mass and energy resolution, respectively, comparing to the spectrometer with a standard silicon particle detector for an energy measurement.

  1. 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.

  2. New Measurement of the Scintillation Efficiency of Low-Energy Nuclear Recoils in Liquid Xenon

    E-print Network

    G. Plante; E. Aprile; R. Budnik; B. Choi; K. -L. Giboni; L. W. Goetzke; R. F. Lang; K. E. Lim; A. J. Melgarejo Fernandez

    2011-04-13

    Particle detectors that use liquid xenon (LXe) as detection medium are among the leading technologies in the search for dark matter weakly interacting massive particles (WIMPs). A key enabling element has been the low-energy detection threshold for recoiling nuclei produced by the interaction of WIMPs in LXe targets. In these detectors, the nuclear recoil energy scale is based on the LXe scintillation signal and thus requires knowledge of the relative scintillation efficiency of nuclear recoils, Leff. The uncertainty in Leff at low energies is the largest systematic uncertainty in the reported results from LXe WIMP searches at low masses. In the context of the XENON Dark Matter project, a new LXe scintillation detector has been designed and built specifically for the measurement of Leff at low energies, with an emphasis on maximizing the scintillation light detection efficiency to obtain the lowest possible energy threshold. We report new measurements of Leff at low energies performed with this detector. Our results suggest a Leff which slowly decreases with energy, from 0.144 +/- 0.009 at 15 keV down to 0.088 +0.014 -0.015 at 3 keV.

  3. A coherent understanding of low-energy nuclear recoils in liquid xenon

    SciTech Connect

    Sorensen, Peter

    2010-09-01

    Liquid xenon detectors such as XENON10 and XENON100 obtain a significant fraction of their sensitivity to light (?<10 GeV) particle dark matter by looking for nuclear recoils of only a few keV, just above the detector threshold. Yet in this energy regime a correct treatment of the detector threshold and resolution remains unclear. The energy dependence of the scintillation yield of liquid xenon for nuclear recoils also bears heavily on detector sensitivity, yet numerous measurements have not succeeded in obtaining concordant results. In this article we show that the ratio of detected ionization to scintillation can be leveraged to constrain the scintillation yield. We also present a rigorous treatment of liquid xenon detector threshold and energy resolution. Notably, the effective energy resolution differs significantly from a simple Poisson distribution. We conclude with a calculation of dark matter exclusion limits, and show that existing data from liquid xenon detectors strongly constrain recent interpretations of light dark matter.

  4. Pulse-shape discrimination between electron and nuclear recoils in a NaI(Tl) crystal

    NASA Astrophysics Data System (ADS)

    Lee, H. S.; Adhikari, G.; Adhikari, P.; Choi, S.; Hahn, I. S.; Jeon, E. J.; Joo, H. W.; Kang, W. G.; Kim, G. B.; Kim, H. J.; Kim, H. O.; Kim, K. W.; Kim, N. Y.; Kim, S. K.; Kim, Y. D.; Kim, Y. H.; Lee, J. H.; Lee, M. H.; Leonard, D. S.; Li, J.; Oh, S. Y.; Olsen, S. L.; Park, H. K.; Park, H. S.; Park, K. S.; Shim, J. H.; So, J. H.

    2015-08-01

    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 ?-rays from a 137Cs 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·year of data from NaI detectors is estimated with simulated experiments, using the standard halo model.

  5. Two Years of Chemical Sampling on Meridiani Planum by the Alpha Particle X-Ray Spectrometer Onboard the Mars Exploration Rover Opportunity

    NASA Technical Reports Server (NTRS)

    Bruckner, J.; Gellert, R.; Clark, B.C.; Dreibus, G.; Rieder, R.; Wanke, H.; d'Uston, C.; Economou, T.; Klingelhofer, G.; Lugmair, G.; Ming, D.W.; Squyres, S.W.; Yen, A.; Zipfel, J.

    2006-01-01

    For over two terrestrial years, the Mars Exploration Rover Opportunity has been exploring the martian surface at Meridiani Planum using the Athena instrument payload [1], including the Alpha Particle X-Ray Spectrometer (APXS). The APXS has a small sensor head that is mounted on the robotic arm of the rover. The chemistry, mineralogy and morphology of selected samples were investigated by the APXS along with the Moessbauer Spectrometer (MB) and the Microscopic Imager (MI). The Rock Abrasion Tool (RAT) provided the possibility to dust and/or abrade rock surfaces down to several millimeters to expose fresh material for analysis. We report here on APXS data gathered along the nearly 6-kilometers long traverse in craters and plains of Meridiani.

  6. 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.

  7. Heavy-to-light Meson Form Factors at Large Recoil

    SciTech Connect

    Hill, Richard J.; /SLAC

    2005-05-27

    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, and how lattice data can be used to study properties such as the energy scaling laws obeyed by the individual components. Symmetry relations between different form factors (F{sub +}, F{sub 0} and F{sub T}), and between different heavy initial-state mesons (B and D), are derived in the combined heavy-quark and large-recoil limits, and are shown to generalize corresponding relations valid at small recoil. Form factor parameterizations that are consistent with the large-recoil limit are discussed.

  8. 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.

  9. 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.

    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.

  10. 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.

  11. Thermodynamic magnon recoil for domain wall motion

    NASA Astrophysics Data System (ADS)

    Yan, Peng; Cao, Yunshan; Sinova, Jairo

    2015-09-01

    We predict a thermodynamic magnon recoil effect for domain wall motions in the presence of temperature gradients. All current thermodynamic theories assert that a magnetic domain wall must move toward the hotter side, based on equilibrium thermodynamic arguments. Microscopic calculations, on the other hand, show that a domain wall can move either along or against the direction of heat currents, depending on how strong the magnonic heat currents are reflected by the domain wall. We have resolved the inconsistency between these two approaches by augmenting the theory in the presence of thermal gradients by incorporating in the free energy of domain walls a heat current term present in nonequilibrium steady states. The condition to observe a domain wall propagation toward the colder regime is derived analytically and can be tested by future experiments.

  12. Designing experimental setup and procedures for studying alpha-particle-induced adaptive response in zebrafish embryos in vivo

    E-print Network

    Yu, Peter K.N.

    in zebrafish embryos in vivo V.W.Y. Choi a , R.K.K. Lam a , E.Y.W. Chong a , S.H. Cheng b , K.N. Yu a track detector PADC Biological effects Adaptive response Zebrafish embryos a b s t r a c t The present-particle-induced adaptive response in zebrafish embryos in vivo. Thin PADC films with a thickness of 16 lm were fabricated

  13. 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.

  14. On the features of bursts of neutrons, hard x-rays and alpha-particles in the pulse vacuum discharge with a virtual cathode and self-organization

    NASA Astrophysics Data System (ADS)

    Kurilenkov, Yu K.; Tarakanov, V. P.; Gus'kov, S. Yu; Samoylov, I. S.; Ostashev, V. E.

    2015-11-01

    In this paper, we continue the discussion of the experimental results on the yield of DD neutrons and hard x-rays in the nanosecond vacuum discharge (NVD) with a virtual cathode, which was started in the previous article of this issue, and previously (Kurilenkov Y K et al 2006 J. Phys. A: Math. Gen. 39 4375). We have considered here the regimes of very dense interelectrode aerosol ensembles, in which diffusion of even hard x-rays is found. The yield of DD neutrons in these regimes is conditioned not only by the head-on deuteron-deuteron collisions in the potential well of virtual cathode, but also by the channel of “deuteron-deuterium cluster” reaction, which exceeds overall yield of neutrons per a shot by more than an order of magnitude, bringing it up to ? 107/(4?). Very bright bursts of hard x-rays are also represented and discussed here. Presumably, their nature may be associated with the appearance in the NVD of some properties of random laser in the x-ray spectrum. Good preceding agreeing of the experiment on the DD fusion in the NVD with its particle-in-cell (PIC) simulations provides a basis to begin consideration of nuclear burning “proton-boron” in the NVD, which will be accompanied by the release of alpha particles only. With this objective in view, there has been started the PIC-simulation of aneutronic burning of p-B11, and its preliminary results are presented.

  15. 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

  16. Nuclear Structure Studies from Hg and Au Alpha Decay Chains

    NASA Astrophysics Data System (ADS)

    Goon, J. Tm.; Bingham, C. R.; Hartley, D. J.; Zhang, Jing-Ye; Riedinger, L. L.; Danchev, M.; Kondev, F. G.; Carpenter, M. P.; Janssens, R. V. F.; Abu Saleem, K. H.; Ahmad, I.; Davids, C. N.; Heinz, A.; Khoo, T. L.; Lauritsen, T.; Lister, C. J.; Poli, G. L.; Seweryniak, D.; Wiedenhover, I.; Ma, W. C.; Amro, H.; Reviol, W.; Cizewski, J. A.; Smith, M.

    2003-04-01

    Neutron deficient nuclei near the Z = 82 shell gap have been a source of great interest. This region is known to exhibit the phenomena of shape-coexistence and triaxiality. Alpha decay study of these nuclei coupled with gamma-rayspectroscopy data can give a better understanding of their nuclear structure properties. The decay chains of ^173-177Au and ^175-179Hg were studied following the bombardment of ^92,94,96Mo targets with ^84Sr beam from the ATLAS accelerator at the Argonne National Laboratory. The experiment utilized the Gammasphere array in conjunction with the Fragment Mass Analyzer (FMA) for mass identification and a Double-sided Silicon Strip Detector (DSSD) that was used to detect the recoiling implants and the alpha particles associated with each nuclide. An array of four Ge detectors and a low-energy photon spectrometer (LEPS) was used at the focal plane of the FMA to detect ? rays in coincidence with the ? particles. This information was used to elucidate the ?-decay fine structures. Inverse radioactive decay tagging was also useful in assigning certain fine structure ? peaks to a particular nuclide. New ? decay lines were observed and their energies, and half-lives were measured. These include fine structure lines in the ? decays of ^174,176Au and ^173Pt. The decay schemes resulting from the fine structure observations will be presented. The ? decay reduced widths are used to suggest spin and parity assignments. The structure of these states will be discussed in the framework of the Nilsson model and alpha decay selection rules. * This work is supported by the Department of Energy through contract numbers DE-FG02-96ER40983 (UT), W-31-109-ENG-38 (ANL), DE-FG02-95ER40939 (MSU), DE-FG05-88ER40406 (WU), and by the National Science Foundation (RU

  17. Modeling the Observability of Recoiling Black Holes as Offset Quasars

    NASA Astrophysics Data System (ADS)

    Blecha, Laura; Torrey, Paul; Vogelsberger, Mark; Genel, Shy; Springel, Volker; Sijacki, Debora; Snyder, Gregory; Bird, Simeon; Nelson, Dylan; Xu, Dandan; Hernquist, Lars

    2015-08-01

    The merger of two supermassive black holes (SMBHs) imparts a gravitational-wave (GW) recoil kick to the remnant SMBH. In extreme cases these kicks may be thousands of km/s -- enough to easily eject them from their host galaxies. Moderate recoil kicks may also cause substantial displacements of the SMBH, however. An actively-accreting, recoiling SMBH may be observable as an offset quasar. Prior to the advent of a space-based GW observatory, detections of these offset quasars may offer the best chance for identifying recent SMBH mergers. Indeed, observational searches for recoiling quasars have already identified several promising candidates. However, systematic searches for recoils are currently hampered by large uncertainties regarding how often offset quasars should be observable, where they are most likely to be found, and whether BH spin alignment prior to merger is efficient at suppressing large recoils. Motivated by this, we have developed a model for the observable population of recoiling quasars in a cosmological framework, utilizing detailed information about the progenitor galaxies from state-of-the-art cosmological hydrodynamic simulations (the Illustris Project). The model for offset quasar lifetimes includes a physically-motivated, time-dependent model for accretion onto kicked SMBHs, and results are analyzed for a range of possible BH spin alignment models. We find that the observability of offset quasars depends strongly on the efficiency of pre-merger spin alignment, with promising indications that observations of recoils could distinguish between at least the extreme limits of spin alignment models. Our results also suggest that observable offset quasars should inhabit preferred types of host galaxies, where again these populations depend on the degree of pre-merger spin alignment. These findings will be valuable for planned and future dedicated searches for recoiling quasars, and they indicate that such objects might be used to place indirect constraints on SMBH spins.

  18. Alpha decay of the new isotope 215U

    NASA Astrophysics Data System (ADS)

    Yang, H. B.; Zhang, Z. Y.; Wang, J. G.; Gan, Z. G.; Ma, L.; Yu, L.; Jiang, J.; Tian, Y. L.; Ding, B.; Guo, S.; Wang, Y. S.; Huang, T. H.; Sun, M. D.; Wang, K. L.; Zhou, S. G.; Ren, Z. Z.; Zhou, X. H.; Xu, H. S.; Xiao, G. Q.

    2015-07-01

    The new neutron-deficient isotope 215U was produced in the complete-fusion reaction 180W (40Ar, 5n) 215U. Evaporation residues recoiled from the target were separated in flight from the primary beam by the gas-filled recoil separator SHANS and subsequently identified on the basis of energy-position-time correlation measurement. The -particle energy and half-life of 215U were determined to be MeV and ms, respectively.

  19. Difference between a Photon's Momentum and an Atom's Recoil

    SciTech Connect

    Gibble, Kurt

    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.

  20. Quenching Factor for Low Energy Nuclear Recoils in a Plastic Scintillator

    E-print Network

    L. Reichhart; D. Yu. Akimov; H. M. Araujo; E. J. Barnes; V. A. Belov; A. A. Burenkov; V. Chepel; A. Currie; L. DeViveiros; B. Edwards; V. Francis; C. Ghag; A. Hollingsworth; M. Horn; G. E. Kalmus; A. S. Kobyakin; A. G. Kovalenko; V. N. Lebedenko; A. Lindote; M. I. Lopes; R. Luscher; P. Majewski; A. St J. Murphy; F. Neves; S. M. Paling; J. Pinto da Cunha; R. Preece; J. J. Quenby; P. R. Scovell; C. Silva; V. N. Solovov; N. J. T. Smith; P. F. Smith; V. N. Stekhanov; T. J. Sumner; C. Thorne; R. J. Walker

    2011-11-09

    Plastic scintillators are widely used in industry, medicine and scientific research, including nuclear and particle physics. Although one of their most common applications is in neutron detection, experimental data on their response to low-energy nuclear recoils are scarce. Here, the relative scintillation efficiency for neutron-induced nuclear recoils in a polystyrene-based plastic scintillator (UPS-923A) is presented, exploring recoil energies between 125 keV and 850 keV. Monte Carlo simulations, incorporating light collection efficiency and energy resolution effects, are used to generate neutron scattering spectra which are matched to observed distributions of scintillation signals to parameterise the energy-dependent quenching factor. At energies above 300 keV the dependence is reasonably described using the semi-empirical formulation of Birks and a kB factor of (0.014+/-0.002) g/MeVcm^2 has been determined. Below that energy the measured quenching factor falls more steeply than predicted by the Birks formalism.

  1. 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.

  2. Event counting alpha detector

    DOEpatents

    Bolton, R.D.; MacArthur, D.W.

    1996-08-27

    An electrostatic detector is disclosed 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. 6 figs.

  3. Alpha voltaic batteries and methods thereof

    NASA Technical Reports Server (NTRS)

    Raffaelle, Ryne P. (Inventor); Jenkins, Phillip (Inventor); Wilt, David (Inventor); Scheiman, David (Inventor); Chubb, Donald (Inventor); Castro, Stephanie (Inventor)

    2011-01-01

    An alpha voltaic battery includes at least one layer of a semiconductor material comprising at least one p/n junction, at least one absorption and conversion layer on the at least one layer of semiconductor layer, and at least one alpha particle emitter. The absorption and conversion layer prevents at least a portion of alpha particles from the alpha particle emitter from damaging the p/n junction in the layer of semiconductor material. The absorption and conversion layer also converts at least a portion of energy from the alpha particles into electron-hole pairs for collection by the one p/n junction in the layer of semiconductor material.

  4. Particle mesh simulations of the Lyman-alpha forest and the signature of Baryon Acoustic Oscillations in the intergalactic medium

    E-print Network

    White, Martin; Carlson, Jordan; Heitmann, Katrin; Habib, Salman; Fasel, Patricia; Daniel, David; Lukic, Zarija

    2009-01-01

    We present a set of ultra-large particle-mesh simulations of the LyA forest targeted at understanding the imprint of baryon acoustic oscillations (BAO) in the inter-galactic medium. We use 9 dark matter only simulations which can, for the first time, simultaneously resolve the Jeans scale of the intergalactic gas while covering the large volumes required to adequately sample the acoustic feature. Mock absorption spectra are generated using the fluctuating Gunn-Peterson approximation which have approximately correct flux probability density functions (PDFs) and small-scale power spectra. On larger scales there is clear evidence in the redshift space correlation function for an acoustic feature, which matches a linear theory template with constant bias. These spectra, which we make publicly available, can be used to test pipelines, plan future experiments and model various physical effects. As an illustration we discuss the basic properties of the acoustic signal in the forest, the scaling of errors with noise ...

  5. Design of the SUPERB Recoil Separator

    NASA Astrophysics Data System (ADS)

    Jackson, Zachary; Carpenter, Lisa; Amthor, Matt

    2013-10-01

    The reaccelerator ReA12 upgrade planned at the National Superconducting Cyclotron Lab (NSCL) at Michigan State University will produce higher energy rare isotope beams close to the neutron and proton drip lines. We present one option for the recoil separator which aims to take full advantage of the new capabilities of ReA12 in studying rare isotopes. The Separator for Unique Products of Experiments with Radioactive Beams (SUPERB), patterned after the second half of the Super Separator-Spectrometer (S3) currently under construction at the Grand Accélérateur National d'Ions Lourds (GANIL). This design includes both electric and magnetic dipoles and this will allow physical separation by mass-to-charge ratio (m/q) with a maximum solid angle of 26 msr and a maximum magnetic rigidity of 1.44 Tm. This design also allows for flexibility of optical modes. Both large acceptance and unit magnification modes will be presented. Also, a fully magnetic configuration is considered that would eliminate the expected electric rigidity limit of 10 MV and increase the maximum magnetic rigidity to 1.92 Tm. We will present optical designs and simulations of SUBERB developed in the code COSY Infinity including a first order system and a higher order Monte Carlo calculation simulating 100Sn production. This research was funded by the NSF REU program, grant PHY-1165694 with additional support from the DoD ASSURE program.

  6. Binary Black Hole Mergers and Recoil Kicks

    NASA Technical Reports Server (NTRS)

    Centrella, Joan; Baker, J.; Choi, D.; Koppitz, M.; vanMeter, J.; Miller, C.

    2006-01-01

    Recent developments in numerical relativity have made it possible to follow reliably the coalescence of two black holes from near the innermost stable circular orbit to final ringdown. This opens up a wide variety of exciting astrophysical applications of these simulations. Chief among these is the net kick received when two unequal mass or spinning black holes merge. The magnitude of this kick has bearing on the production and growth of supermassive black holes during the epoch of structure formation, and on the retention of black holes in stellar clusters. Here we report the first accurate numerical calculation of this kick, for two nonspinning black holes in a 1.5:1 mass ratio, which is expected based on analytic considerations to give a significant fraction of the maximum possible recoil. We have performed multiple runs with different initial separations, orbital angular momenta, resolutions, extraction radii, and gauges. The full range of our kick speeds is 86-116 kilometers per second, and the most reliable runs give kicks between 86 and 97 kilometers per second. This is intermediate between the estimates from two recent post-Newtonian analyses and suggests that at redshifts z greater than 10, halos with masses less than 10(exp 9) M(sub SUN) will have difficulty retaining coalesced black holes after major mergers.

  7. RECOILING SUPERMASSIVE BLACK HOLES IN SPIN-FLIP RADIO GALAXIES

    SciTech Connect

    Liu, F. K.; Wang Dong; Chen Xian

    2012-02-20

    Numerical relativity simulations predict that coalescence of supermassive black hole (SMBH) binaries leads not only to a spin flip but also to a recoiling of the merger remnant SMBHs. In the literature, X-shaped radio sources are popularly suggested to be candidates for SMBH mergers with spin flip of jet-ejecting SMBHs. Here we investigate the spectral and spatial observational signatures of the recoiling SMBHs in radio sources undergoing black hole spin flip. Our results show that SMBHs in most spin-flip radio sources have mass ratio q {approx}> 0.3 with a minimum possible value q{sub min} {approx_equal} 0.05. For major mergers, the remnant SMBHs can get a kick velocity as high as 2100 km s{sup -1} in the direction within an angle {approx}< 40 Degree-Sign relative to the spin axes of remnant SMBHs, implying that recoiling quasars are biased to be with high Doppler-shifted broad emission lines while recoiling radio galaxies are biased to large apparent spatial off-center displacements. We also calculate the distribution functions of line-of-sight velocity and apparent spatial off-center displacements for spin-flip radio sources with different apparent jet reorientation angles. Our results show that the larger the apparent jet reorientation angle is, the larger the Doppler-shifting recoiling velocity and apparent spatial off-center displacement will be. We investigate the effects of recoiling velocity on the dust torus in spin-flip radio sources and suggest that recoiling of SMBHs would lead to 'dust-poor' active galactic nuclei. Finally, we collect a sample of 19 X-shaped radio objects and for each object give the probability of detecting the predicted signatures of recoiling SMBH.

  8. 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.

  9. Rosuvastatin Alters the Proteome of High Density Lipoproteins: Generation of alpha-1-antitrypsin Enriched Particles with Anti-inflammatory Properties.

    PubMed

    Gordon, Scott M; McKenzie, Benjamin; Kemeh, Georgina; Sampson, Maureen; Perl, Shira; Young, Neal S; Fessler, Michael B; Remaley, Alan T

    2015-12-01

    Statins lower plasma cholesterol by as much as 50%, thus reducing future cardiovascular events. However, the physiological effects of statins are diverse and not all are related to low density lipoprotein cholesterol (LDL-C) lowering. We performed a small clinical pilot study to assess the impact of statins on lipoprotein-associated proteins in healthy individuals (n = 10) with normal LDL-C (<130 mg/dL), who were treated with rosuvastatin (20 mg/day) for 28 days. Proteomic analysis of size-exclusion chromatography isolated LDL, large high density lipoprotein (HDL-L), and small HDL (HDL-S) fractions and spectral counting was used to compare relative protein detection before and after statin therapy. Significant protein changes were found in each lipoprotein pool and included both increases and decreases in several proteins involved in lipoprotein metabolism, complement regulation and acute phase response. The most dramatic effect of the rosuvastatin treatment was an increase in ?-1-antirypsin (A1AT) spectral counts associated with HDL-L particles. Quantitative measurement by ELISA confirmed an average 5.7-fold increase in HDL-L associated A1AT. Molecular modeling predictions indicated that the hydrophobic reactive center loop of A1AT, the functional domain responsible for its protease inhibitor activity, is likely involved in lipid binding and association with HDL was found to protect A1AT against oxidative inactivation. Cell culture experiments, using J774 macrophages, demonstrated that the association of A1AT with HDL enhances its antiprotease activity, preventing elastase induced production of tumor necrosis factor ?. In conclusion, we show that statins can significantly alter the protein composition of both LDL and HDL and our studies reveal a novel functional relationship between A1AT and HDL. The up-regulation of A1AT on HDL enhances its anti-inflammatory functionality, which may contribute to the non-lipid lowering beneficial effects of statins. PMID:26483418

  10. 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

  11. Membrane-Dependent Bystander Effect Contributes to Amplification of the Response to Alpha-Particle Irradiation in Targeted and Nontargeted Cells

    SciTech Connect

    Hanot, Maite; Hoarau, Jim; Carriere, Marie; Angulo, Jaime F.; Khodja, Hicham

    2009-11-15

    Purpose: Free radicals are believed to play an active role in the bystander response. This study investigated their origin as well as their temporal and spatial impacts in the bystander effect. Methods and Materials: We employed a precise alpha-particle microbeam to target a small fraction of subconfluent osteoblastic cells (MC3T3-E1). gammaH2AX-53BP1 foci, oxidative metabolism changes, and micronuclei induction in targeted and bystander cells were assessed. Results: Cellular membranes and mitochondria were identified as two distinct reactive oxygen species producers. The global oxidative stress observed after irradiation was significantly attenuated after cells were treated with filipin, evidence for the primal role of membrane in the bystander effect. To determine the membrane's impact at a cellular level, micronuclei yield was measured when various fractions of the cell population were individually targeted while the dose per cell remained constant. Induction of micronuclei increased in bystander cells as well as in targeted cells and was attenuated by filipin treatment, demonstrating a role for bystander signals between irradiated cells in an autocrine/paracrine manner. Conclusions: A complex interaction of direct irradiation and bystander signals leads to a membrane-dependent amplification of cell responses that could influence therapeutic outcomes in tissues exposed to low doses or to environmental exposure.

  12. Labeling monoclonal antibodies and F(ab')2 fragments with the alpha-particle-emitting nuclide astatine-211: preservation of immunoreactivity and in vivo localizing capacity.

    PubMed Central

    Zalutsky, M R; Garg, P K; Friedman, H S; Bigner, D D

    1989-01-01

    alpha-Particles such as those emitted by 211At may be advantageous for radioimmunotherapy since they are radiation of high linear energy transfer, depositing high energy over a short distance. Here we describe a strategy for labeling monoclonal antibodies and F(ab')2 fragments with 211At by means of the bifunctional reagent N-succinimidyl 3-(trimethylstannyl)benzoate. An intact antibody, 81C6, and the F(ab')2 fragment of Me1-14 (both reactive with human gliomas) were labeled with 211At in high yield and with a specific activity of up to 4 mCi/mg in a time frame compatible with the 7.2-hr half-life of 211At. Quantitative in vivo binding assays demonstrated that radioastatination was accomplished with maintenance of high specific binding and affinity. Comparison of the biodistribution of 211At-labeled Me1-14 F(ab')2 to that of a nonspecific antibody fragment labeled with 211At and 131I in athymic mice bearing D-54 MG human glioma xenografts demonstrated selective and specific targeting of 211At-labeled antibody in this human tumor model. PMID:2476813

  13. 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.

  14. Lorentz Violation and Alpha-Decay

    E-print Network

    Brett Altschul

    2008-12-11

    Relating the effective Lorentz violation coefficients for composite particles to the coefficients for their constituent fields is a challenging problem. We calculate the Lorentz violation coefficients relevant to the dynamics of an alpha-particle in terms of proton and neutron coefficients. The alpha-particle coefficients would lead to anisotropies in the alpha-decays of nuclei, and because the decay process involves quantum tunneling, the effects of any Lorentz violations could be exponentially enhanced.

  15. Three-Loop Radiative-Recoil Corrections to Hyperfine Splitting in Muonium: Diagrams with Polarization Loops

    SciTech Connect

    Eides, Michael I.; Shelyuto, Valery A.

    2009-09-25

    We consider three-loop radiative-recoil corrections to hyperfine splitting in muonium generated by the diagrams with electron and muon vacuum polarizations. We calculate single-logarithmic and nonlogarithmic contributions of order alpha{sup 3}(m/M)E{sub F} generated by gauge invariant sets of diagrams with electron and muon polarization insertions in the electron and muon factors. Combining these corrections with the older results, we obtain total contribution to hyperfine splitting generated by all diagrams with electron and muon polarization loops. The calculation of this contribution completes an important stage in the implementation of the program of reduction of the theoretical uncertainty of hyperfine splitting below 10 Hz. The new results improve the theory of hyperfine splitting and affect the value of the electron-muon mass ratio extracted from experimental data on muonium hyperfine splitting.

  16. Long-range alpha detector

    SciTech Connect

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

    1991-01-01

    Historically, alpha-particle and alpha-contamination detectors have been limited by the very short range of alpha particles in air and by relatively poor sensitivity even if the particles are intercepted. Alpha detectors have had to be operated in a vacuum or in close proximity to the source if reasonable efficiency is desired. Alpha particles interact with the ambient air, producing ionization in the air at the rate of {approximately}30,000 ion pairs per mega-electron-volt of alpha energy. These charges can be transported over significant distances (several meters) in a moving current of air generated by a small fan. An ion chamber located in front of the fan measures the current carried by the moving ions. The long-range alpha detector (LRAD) offers several advantages over more traditional alpha detectors. First and foremost, it can operate efficiently even if the contamination is not easily accessible. Second, ions generated by contamination in crevices and other unmonitorable locations can be detected if the airflow penetrates those areas. Third, all of the contamination on a large surface will generate ions that can be detected in a single detector; hence, the detector's sensitivity to distributed sources is not limited by the size of the probe. Finally, a simple ion chamber can detect very small electric currents, making this technique potentially quite sensitive.

  17. Environmental alpha contamination monitoring with the LRAD

    SciTech Connect

    MacArthur, D.W.; Allander, K.S.; Bounds, J.A.; Catlett, M.M.; Caress, R.W.; Rutherford, D.A.

    1993-12-31

    Traditional alpha detection systems used for environmental analysis of potential alpha contamination are hampered by relative poor sensitivity and by the short range of alpha particles in air. The long-range alpha detector (LRAD) addresses both of these limitations by detecting the ionized gas molecules created by the alpha particles` interaction with the ambient air, rather than the alpha particles themselves. In addition, LRAD monitors are sensitive to contamination in any location to which air can penetrate and are able to monitor large surfaces simultaneously. All of these characteristics are important in environmental monitoring for alpha contamination. The authors will present the basic LRAD technology as well as applications to soil, water, and air monitors. Results from field tests of several of these alpha monitors will be presented.

  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. The rejoining of DNA double-strand breaks following irradiation with 238Pu alpha-particles: evidence for a fast component of repair as measured by neutral filter elution.

    PubMed

    Fox, J C; McNally, N J

    1990-03-01

    The induction and repair of DNA double-strand breaks (DSB) following exposure to 238Pu alpha-particles was examined in V79-379A cells. The technique of neutral filter elution was used in these investigations at both pH 9.6 and pH 7.2. The initial dsb yield was found to be similar to that seen after 250 kVp X-ray or 2.3 MeV neutron exposure. However, the pattern of dsb rejoining after alpha-particle irradiation did not follow that seen after X-rays or neutrons. A very fast initial component, complete within 2 min of incubation following irradiation, removed 70 per cent of the dsb seen after 40 Gy alpha-particles; very little slow rejoining was seen. This contrasts sharply with the dsb rejoining seen after X-ray or neutron exposure, and presumably reflects the differences in the nature of the dsb induced and the way they are repaired. PMID:1968944

  20. Treatment of HER2-Expressing Breast Cancer and Ovarian Cancer Cells With Alpha Particle-Emitting {sup 227}Th-Trastuzumab

    SciTech Connect

    Heyerdahl, Helen; Krogh, Cecilie; Borrebaek, Jorgen; Larsen, Asmund; Dahle, Jostein

    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.

  1. Efficient one-step radiolabeling of monoclonal antibodies to high specific activity with Actinium-225 for alpha-particle radioimmunotherapy of cancer

    PubMed Central

    Maguire, William F.; McDevitt, Michael R.; Smith-Jones, Peter M.; Scheinberg, David A.

    2015-01-01

    Targeted alpha-particle radiation using the radioisotope 225Actinium (225Ac) is a promising form of therapy for various types of cancer. Historical obstacles to the use of 225Ac have been the difficulty in finding suitable chelators to stably attach it to targeting vehicles such as peptides and monoclonal antibodies, the low specific activities of the products, and the lack of cost-effective radiolabeling procedures. We initially solved the first problem with a procedure involving two chemical steps that has been used as a standard in preclinical and clinical studies. However, this procedure involves the loss of 90% of the input 225Ac. A more efficient, economical process is needed to facilitate the more widespread use of 225Ac. Methods We conjugated representative antibodies with two forms of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), as well as other chelators as controls. We developed conditions to radiolabel these constructs in one chemical step and characterized their stability, immunoreactivity, biodistribution, and therapeutic efficacy in healthy and tumor-bearing mice. Results DOTA- antibody constructs were labeled to a wide range of specific activities in one chemical step at 37 °C. Radiochemical yields were approximately 10-fold higher and specific activities were up to 30-fold higher than with the previous approach. The products retained immunoreactivity and were stable to serum challenge in vitro and in mice. Labeling kinetics of DOTA- antibody constructs linked through a benzyl isothiocyanate linkage were more favorable than those linked through a N-hydroxysuccinimide linkage. Tissue distribution was similar but not identical between the constructs. The constructs produced specific therapeutic responses in a mouse model of acute myeloid leukemia. Conclusion We have characterized an efficient, one-step radiolabeling method that produces stable, therapeutically active conjugates of antibodies with 225Ac at high specific activity. We propose that this technology greatly expands the possible clinical applications of 225Ac -monoclonal antibodies. PMID:24982438

  2. Long-range alpha detection

    SciTech Connect

    Kasper, K.

    1998-12-01

    The detection and measurement of alpha contamination is not an easy task. An alpha particle`s characteristic high charge and large mass make it highly interactive with surrounding matter. The particle is often absorbed before its presence can be sensed with a detector. Los Alamos National Laboratory has studied this problem and has developed an improved process to detect alpha-emitting contaminants. The process is called long-range alpha detection (LRAD). The LRAD process focuses on the collection and measurement of ions created as a result of an alpha particle`s interaction with air. With only about 35 eV necessary to create an ion pair, a typical 5-MeV alpha particle, upon emission from its maternal nucleus, creates about 150,000 pairs of charged particles. In air these charged particles take several seconds to locate a mate and become electrically neutral. During this time, ions can be pulled away from the source, collected, and measured. Ions can be motivated to a collection device by using an electric field or by moving the air mass in which the ions are located. The collected charges create a small but discrete current that can give some useful information about the alpha-emitting source. In this article, two commercially available applications of the LRADS technology will be discussed. One of these, a device used primarily for pipe monitoring, is from BNFL Instruments, Inc. The other is a monitoring box of sorts from Eberline that will produce an alpha measurement on anything that is placed in the box.

  3. 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.

  4. 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.

  5. 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.

  6. Ar-39 recoil losses and presolar ages in Allende inclusions

    NASA Technical Reports Server (NTRS)

    Villa, I. M.; Huneke, J. C.; Wasserburg, G. J.

    1983-01-01

    Argon analyses were performed for five coarse-grained, Ca-Al-rich inclusions from the Allende meteorite. The samples were neutron-irradiated in evacuated ampuoles, and the Ar in the ampuoles and in the samples was analyzed. Up to 60 percent of Ar-39 was lost from the samples into the ampuoles due to recoil during neutron-irradiation; this loss resulted in substantial increases in the apparent Ar-40-Ar-39 ages of the samples. Substantial amounts of trapped Ar-36 of unknown origin were found in the inclusions, and the presence of trapped Ar-40 could not be ruled out. It is inferred that the interpretation of high Ar-40/K-40 ratios as very high (presolar) ages may be subject to question. It is noted that the degrees of Ar-39 recoil loss reported is comparable to recoil loss in terrestrial rocks and cannot be attributed to KCl contamination of the samples.

  7. 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.

  8. Angular distributions of very low energy recoil ions

    SciTech Connect

    Gonzalez Lepera, C.E.; Breinig, M.; Burgdoerfer, J.; DeSerio, R.; Elston, S.B.; Gibbons, J.P.; Huelskoetter, H.P.; Liljeby, L.; Vane, C.R.; Sellin, I.A.

    1986-01-01

    We present the first measurements of the angular distribution of recoil ions near 90/sup 0/ with respect to the incident projectile direction. Beams of 22.5 and 33 MeV chlorine ions (incident charge states q =4,5,8) have been used as ''hammer'' beams incident on Ne atoms. We confirm the long standing assumption that these recoil ions are ejected preferentially at angles near 90/sup 0/ with respect to the primary beam direction and with energies typically less than 5 eV. Recoil ions ejected around 90/sup 0/ have an energy distribution appreciably wider than those ejected at either larger or smaller angles. 9 refs., 6 figs.

  9. Pulse-shape discrimination of scintillation from alpha and beta particles with liquid scintillator and Geiger-mode multipixel avalanche diodes

    E-print Network

    I. Kreslo; I. Badhrees; S. Delaquis; A. Ereditato; S. Janos; M. Messina; U. Moser; B. Rossi; M. Zeller

    2011-06-23

    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.

  10. Exclusion of Leptophilic Dark Matter Models using XENON100 Electronic Recoil Data

    E-print Network

    Aprile, E; Alfonsi, M; Arazi, L; Arisaka, K; Arneodo, F; Auger, M; Balan, C; Barrow, P; Baudis, L; Bauermeister, B; Behrens, A; Brown, A; Brown, E; Bruenner, S; Bruno, G; Budnik, R; Buetikofer, L; Cardoso, J M R; Cervantes, M; Coderre, D; Colijn, A P; Contreras, H; Cussonneau, J P; Decowski, M P; Di Giovanni, A; Duchovni, E; Fattori, S; Ferella, A D; Fieguth, A; Fulgione, W; Gao, F; Garbini, M; Geis, C; Goetzke, L W; Grignon, C; Gross, E; Hampel, W; Itay, R; Kaether, F; Kaminsky, B; Kessler, G; Kish, A; Landsman, H; Lang, R F; Calloch, M Le; Lellouch, D; Levinson, L; Levy, C; Lindemann, S; Lindner, M; Lopes, J A M; Lyashenko, A; Macmullin, S; Undagoitia, T Marrodan; Masbou, J; Massoli, F V; Paras, D Mayani; Fernandez, A J Melgarejo; Meng, Y; Messina, M; Miguez, B; Molinario, A; Morana, G; Murra, M; Naganoma, J; Ni, K; Oberlack, U; Orrigo, S E A; Pakarha, P; Pantic, E; Persiani, R; Piastra, F; Pienaar, J; Plante, G; Priel, N; Rauch, L; Reichard, S; Reuter, C; Rizzo, A; Rosendahl, S; Santos, J M F dos; Sartorelli, G; Schindler, S; Schreiner, J; Schumann, M; Lavina, L Scotto; Selvi, M; Shagin, P; Simgen, H; Teymourian, A; Thers, D; Tiseni, A; Trinchero, G; Tunnell, C; Vitells, O; Wall, R; Wang, H; Weber, M; Weinheimer, C

    2015-01-01

    Laboratory experiments searching for galactic dark matter particles scattering off nuclei have so far not been able to establish a discovery. We use data from the XENON100 experiment to search for dark matter interacting with electrons. With no evidence for a signal above the low background of our experiment, we exclude a variety of representative dark matter models that would induce electronic recoils. For axial-vector couplings to electrons, we exclude cross-sections above 6x10^(-35) cm^2 for particle masses of m_chi = 2 GeV/c^2. Independent of the dark matter halo, we exclude leptophilic models as explanation for the long-standing DAMA/LIBRA signal, such as couplings to electrons through axial-vector interactions at a 4.4 sigma confidence level, mirror dark matter at 3.6 sigma, and luminous dark matter at 4.6 sigma.

  11. Simulation of Velocity Filters in the Daresbury Recoil Separator at the HRIBF

    NASA Astrophysics Data System (ADS)

    Rogers, J. P.; Kozub, R. L.; Pain, S. D.; Smith, M. S.; Bardayan, D. W.; Liu, Y.; Matos, M.

    2008-10-01

    The Daresbury Recoil Separator (DRS) at Oak Ridge National Lab's (ORNL) Holifield Radioactive Ion Beam Facility (HRIBF) is used for the study of nuclear reactions of astrophysical importance. For example, the DRS enables direct measurements of proton capture reactions on radioactive ions which occur in stellar explosions such as novae and X-ray bursts. The DRS uses velocity filters (Wien filters) that are tuned to transmit the reaction products with a specific velocity while deflecting the unreacted primary beam particles away from the optical axis, where they are stopped on adjustable slits. Data from earlier calculations of the electromagnetic fields inside and around the filters has been implemented into a FORTRAN program to provide accurate calculations and graphic representations of particle trajectories through the Wien filters. This information can be used to predetermine optimum positions of the slits for future experiments. The program will be used as an experimental setup tool for the DRS.

  12. Exclusion of leptophilic dark matter models using XENON100 electronic recoil data

    NASA Astrophysics Data System (ADS)

    Collaboration, The XENON; Aprile, E.; Agostini, F.; Alfonsi, M.; Arazi, L.; Arisaka, K.; Arneodo, F.; Auger, M.; Balan, C.; Barrow, P.; Baudis, L.; Bauermeister, B.; Behrens, A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Cardoso, J. M. R.; Cervantes, M.; Coderre, D.; Colijn, A. P.; Contreras, H.; Cussonneau, J. P.; Decowski, M. P.; Di Giovanni, A.; Duchovni, E.; Fattori, S.; Ferella, A. D.; Fieguth, A.; Fulgione, W.; Gao, F.; Garbini, M.; Geis, C.; Goetzke, L. W.; Grignon, C.; Gross, E.; Hampel, W.; Itay, R.; Kaether, F.; Kaminsky, B.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Le Calloch, M.; Lellouch, D.; Levinson, L.; Levy, C.; Lindemann, S.; Lindner, M.; Lopes, J. A. M.; Lyashenko, A.; Macmullin, S.; Undagoitia, T. Marrodán; Masbou, J.; Massoli, F. V.; Mayani, D.; Fernandez, A. J. Melgarejo; Meng, Y.; Messina, M.; Miguez, B.; Molinario, A.; Morana, G.; Murra, M.; Naganoma, J.; Ni, K.; Oberlack, U.; Orrigo, S. E. A.; Pakarha, P.; Pantic, E.; Persiani, R.; Piastra, F.; Pienaar, J.; Plante, G.; Priel, N.; Rauch, L.; Reichard, S.; Reuter, C.; Rizzo, A.; Rosendahl, S.; dos Santos, J. M. F.; Sartorelli, G.; Schindler, S.; Schreiner, J.; Schumann, M.; Lavina, L. Scotto; Selvi, M.; Shagin, P.; Simgen, H.; Teymourian, A.; Thers, D.; Tiseni, A.; Trinchero, G.; Tunnell, C.; Vitells, O.; Wall, R.; Wang, H.; Weber, M.; Weinheimer, C.

    2015-08-01

    Laboratory experiments searching for galactic dark matter particles scattering off nuclei have so far not been able to establish a discovery. We use data from the XENON100 experiment to search for dark matter interacting with electrons. With no evidence for a signal above the low background of our experiment, we exclude a variety of representative dark matter models that would induce electronic recoils. For axial-vector couplings to electrons, we exclude cross sections above 6 × 10-35 cm2 for particle masses of m? = 2 GeV/c2. Independent of the dark matter halo, we exclude leptophilic models as an explanation for the long-standing DAMA/LIBRA signal, such as couplings to electrons through axial-vector interactions at a 4.4? confidence level, mirror dark matter at 3.6?, and luminous dark matter at 4.6?.

  13. ASTROPHYSICS. Exclusion of leptophilic dark matter models using XENON100 electronic recoil data.

    PubMed

    2015-08-21

    Laboratory experiments searching for galactic dark matter particles scattering off nuclei have so far not been able to establish a discovery. We use data from the XENON100 experiment to search for dark matter interacting with electrons. With no evidence for a signal above the low background of our experiment, we exclude a variety of representative dark matter models that would induce electronic recoils. For axial-vector couplings to electrons, we exclude cross sections above 6 × 10(-35) cm(2) for particle masses of m(?) = 2 GeV/c(2). Independent of the dark matter halo, we exclude leptophilic models as an explanation for the long-standing DAMA/LIBRA signal, such as couplings to electrons through axial-vector interactions at a 4.4? confidence level, mirror dark matter at 3.6?, and luminous dark matter at 4.6?. PMID:26293959

  14. Exclusion of Leptophilic Dark Matter Models using XENON100 Electronic Recoil Data

    E-print Network

    The XENON Collaboration; E. Aprile; F. Agostini; M. Alfonsi; L. Arazi; K. Arisaka; F. Arneodo; M. Auger; C. Balan; P. Barrow; L. Baudis; B. Bauermeister; A. Behrens; A. Brown; E. Brown; S. Bruenner; G. Bruno; R. Budnik; L. Buetikofer; J. M. R. Cardoso; M. Cervantes; D. Coderre; A. P. Colijn; H. Contreras; J. P. Cussonneau; M. P. Decowski; A. Di Giovanni; E. Duchovni; S. Fattori; A. D. Ferella; A. Fieguth; W. Fulgione; F. Gao; M. Garbini; C. Geis; L. W. Goetzke; C. Grignon; E. Gross; W. Hampel; R. Itay; F. Kaether; B. Kaminsky; G. Kessler; A. Kish; H. Landsman; R. F. Lang; M. Le Calloch; D. Lellouch; L. Levinson; C. Levy; S. Lindemann; M. Lindner; J. A. M. Lopes; A. Lyashenko; S. Macmullin; T. Marrodan Undagoitia; J. Masbou; F. V. Massoli; D. Mayani Paras; A. J. Melgarejo Fernandez; Y. Meng; M. Messina; B. Miguez; A. Molinario; G. Morana; M. Murra; J. Naganoma; K. Ni; U. Oberlack; S. E. A. Orrigo; P. Pakarha; E. Pantic; R. Persiani; F. Piastra; J. Pienaar; G. Plante; N. Priel; L. Rauch; S. Reichard; C. Reuter; A. Rizzo; S. Rosendahl; J. M. F. dos Santos; G. Sartorelli; S. Schindler; J. Schreiner; M. Schumann; L. Scotto Lavina; M. Selvi; P. Shagin; H. Simgen; A. Teymourian; D. Thers; A. Tiseni; G. Trinchero; C. Tunnell; O. Vitells; R. Wall; H. Wang; M. Weber; C. Weinheimer

    2015-07-28

    Laboratory experiments searching for galactic dark matter particles scattering off nuclei have so far not been able to establish a discovery. We use data from the XENON100 experiment to search for dark matter interacting with electrons. With no evidence for a signal above the low background of our experiment, we exclude a variety of representative dark matter models that would induce electronic recoils. For axial-vector couplings to electrons, we exclude cross-sections above 6x10^(-35) cm^2 for particle masses of m_chi = 2 GeV/c^2. Independent of the dark matter halo, we exclude leptophilic models as explanation for the long-standing DAMA/LIBRA signal, such as couplings to electrons through axial-vector interactions at a 4.4 sigma confidence level, mirror dark matter at 3.6 sigma, and luminous dark matter at 4.6 sigma.

  15. particles

    NASA Astrophysics Data System (ADS)

    Xia, Yu; Chen, Zhihong; Zhang, Zhengguo; Fang, Xiaoming; Liang, Guozheng

    2014-05-01

    We explore a facile and nontoxic hydrothermal route for synthesis of a Cu2ZnSnS4 nanocrystalline material by using l-cysteine as the sulfur source and ethylenediaminetetraacetic acid (EDTA) as the complexing agent. The effects of the amount of EDTA, the mole ratio of the three metal ions, and the hydrothermal temperature and time on the phase composition of the obtained product have been systematically investigated. The addition of EDTA and an excessive dose of ZnCl2 in the hydrothermal reaction system favor the generation of kesterite Cu2ZnSnS4. Pure kesterite Cu2ZnSnS4 has been synthesized at 180°C for 12 h from the reaction system containing 2 mmol of EDTA at 2:2:1 of Cu/Zn/Sn. It is confirmed by Raman spectroscopy that those binary and ternary phases are absent in the kesterite Cu2ZnSnS4 product. The kesterite Cu2ZnSnS4 material synthesized by the hydrothermal process consists of flower-like particles with 250 to 400 nm in size. It is revealed that the flower-like particles are assembled from single-crystal Cu2ZnSnS4 nanoflakes with ca. 20 nm in size. The band gap of the Cu2ZnSnS4 nanocrystalline material is estimated to be 1.55 eV. The films fabricated from the hierarchical Cu2ZnSnS4 particles exhibit fast photocurrent responses under intermittent visible-light irradiation, implying that they show potentials for use in solar cells and photocatalysis.

  16. Alpha detection on moving surfaces

    SciTech Connect

    MacArthur, D.; Orr, C.; Luff, C.

    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.

  17. Zero-recoil sum rules for ?b ??c form factors

    NASA Astrophysics Data System (ADS)

    Mannel, Thomas; van Dyk, Danny

    2015-12-01

    We set up a zero recoil sum rule to constrain the form factors of the ?b ??c transition. Our results are compared with the recent lattice calculation for these transitions. We find the same situation as in the case for B ?D*: The lattice results practically saturate the sum rules, leaving basically no room for excited states.

  18. Elastic recoil detection (ERD) with extremely heavy ions

    NASA Astrophysics Data System (ADS)

    Forster, J. S.; Currie, P. J.; Davies, J. A.; Siegele, R.; Wallace, S. G.; Zelenitsky, D.

    1996-06-01

    Extremely heavy-ion beams such as 209Bi in elastic recoil detection (ERD) make ERD a uniquely valuable technique for thin-film analysis of elements with mass ? 100. We report ERD measurements of compositional analysis of dinosaur eggshells and bones. We also show the capability of the ERD technique on studies of thin-film, high-temperature superconductors.

  19. A Chimeric 18L1-45RG1 Virus-Like Particle Vaccine Cross-Protects against Oncogenic Alpha-7 Human Papillomavirus Types

    PubMed Central

    Huber, Bettina; Schellenbacher, Christina; Jindra, Christoph; Fink, Dieter; Shafti-Keramat, Saeed; Kirnbauer, Reinhard

    2015-01-01

    Persistent infection with oncogenic human papillomaviruses (HPV) types causes all cervical and a subset of other anogenital and oropharyngeal carcinomas. Four high-risk (hr) mucosal types HPV16, 18, 45, or 59 cause almost all cervical adenocarcinomas (AC), a subset of cervical cancer (CxC). Although the incidence of cervical squamous cell carcinoma (SCC) has dramatically decreased following introduction of Papanicolaou (PAP) screening, the proportion of AC has relatively increased. Cervical SCC arise mainly from the ectocervix, whereas AC originate primarily from the endocervical canal, which is less accessible to obtain viable PAP smears. Licensed (bivalent and quadrivalent) HPV vaccines comprise virus-like particles (VLP) of the most important hr HPV16 and 18, self-assembled from the major capsid protein L1. Due to mainly type-restricted efficacy, both vaccines do not target 13 additional hr mucosal types causing 30% of CxC. The papillomavirus genus alpha species 7 (?7) includes a group of hr types of which HPV18, 45, 59 are proportionally overrepresented in cervical AC and only partially (HPV18) targeted by current vaccines. To target these types, we generated a chimeric vaccine antigen that consists of a cross-neutralizing epitope (homologue of HPV16 RG1) of the L2 minor capsid protein of HPV45 genetically inserted into a surface loop of HPV18 L1 VLP (18L1-45RG1). Vaccination of NZW rabbits with 18L1-45RG1 VLP plus alum-MPL adjuvant induced high-titer neutralizing antibodies against homologous HPV18, that cross-neutralized non-cognate hr ?7 types HPV39, 45, 68, but not HPV59, and low risk HPV70 in vitro, and induced a robust L1-specific cellular immune response. Passive immunization protected mice against experimental vaginal challenge with pseudovirions of HPV18, 39, 45 and 68, but not HPV59 or the distantly related ?9 type HPV16. 18L1-45RG1 VLP might be combined with our previously described 16L1-16RG1 VLP to develop a second generation bivalent vaccine with extended spectrum against hr HPV. PMID:25790098

  20. 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

  1. 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...

  2. 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

    2015-08-26

    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.

  3. New Methods for Targeted Alpha Radiotherapy

    NASA Astrophysics Data System (ADS)

    Robertson, J. David

    2014-03-01

    Targeted radiotherapies based on alpha emitters are a promising alternative to beta emitting radionuclides. Because of their much shorter range, targeted ?-radiotherapy (TAT) agents have great potential for application to small, disseminated tumors and micro metastases and treatment of hematological malignancies consisting of individual, circulating neoplastic cells. A promising approach to TAT is the use of the in vivo ?-generator radionuclides 223 = 11.4 d) and 225Ac 1/2 = 10.0 d). In addition to their longer half-lives, these two isotopes have the potential of dramatically increasing the therapeutic efficacy of TAT as they each emit four ? particles in their decay chain. This principle has recently been exploited in the development of Xofigo®, the first TAT agent approved for clinical use by the U.S. FDA. Xofigo, formulated as 223RaCl2, is used for treatment of metastatic bone cancer in men with castration-resistant prostate cancer. TAT with 223Ra works, however, only in the case of bone cancer because radium, as a chemical analogue of calcium, efficiently targets bone. In order to bring the benefits of TAT with 223Ra or 225Ac to other tumor types, a new delivery method must be devised. Retaining the in vivo ? generator radionuclides at the target site through the decay process is one of the major challenges associated with the development of TAT. Because the recoil energy of the daughter radionuclides from the ?-emission is ~ 100 keV - a value which is four orders of magnitude greater than the energy of a covalent bond - the daughters will not remain bound to the bioconjugate at the targeting site. Various approaches have been attempted to achieve retention of the ?-generator daughter radionuclides at the target site, including incorporation of the in vivo generator into liposomes and fullerenes. Unfortunately, to date single wall liposomes and fullerenes are able to retain less than 10% of the daughter radionuclides. We have recently demonstrated that a multilayered nanoparticle-antibody conjugate can deliver multiple ? radiations from the in vivo ?-generator 225Ac at biologically relevant receptor sites. The nanoparticles retained over 90% of the 221Fr daughter over the course of three weeks in in vitro experiments. In in vivo experiments, approximately 90% of the 213Bi was retained in the target tissue 24 hours after injection of the antibody labeled nanoparticle. An overview of the development and application of this promising, new approach to targeted alpha therapy will be presented.

  4. Long-range alpha detector sample monitoring

    NASA Astrophysics Data System (ADS)

    Johnson, J. D.; Allander, K. S.; Bounds, J. A.; Garner, S. E.; Johnson, J. P.; MacArthur, D. W.; Sprouse, L. L.; Walters, S. G.

    1994-12-01

    Long-range alpha detector (LRAD) systems are designed to monitor alpha sources and contamination by measuring the number of ions created in air by ionizing radiation. Traditional alpha detectors are designed to detect alpha particles directly and must be passed slowly within about 3 cm of an alpha source to operate effectively. LRAD detectors collect the ions created from alpha interactions with air. Therefore, they are better able to monitor equipment and complex surfaces and can be operated at a much greater distance from an alpha source than traditional alpha detectors. Furthermore, because LRAD detectors remain stationary during monitoring, they are less subject to operator error than traditional alpha detectors. This paper will discuss the basic operation as well as recent advances that have been made to LRAD Sample Monitors.

  5. Alpha Thalassemia

    MedlinePLUS

    ... an apparently normal individual has a child with hemoglobin H disease or alpha thalassemia minor. It can ... gene on one chromosome 25% 25% 25% 25% hemoglobin H disease there is a 25% chance with ...

  6. Alpha channeling in rotating plasma with stationary waves Abraham J. Fetterman and Nathaniel J. Fisch

    E-print Network

    the system.14 Alpha particles interact stochastically with radio frequency rf waves, causing average outwardAlpha channeling in rotating plasma with stationary waves Abraham J. Fetterman and Nathaniel J particle energy. Alpha channeling uses radiofrequency waves to remove alpha particles collisionlessly

  7. Experimental Identification of Spin-Parities and Single-Particle Configurations in {sup 257}No and Its {alpha}-Decay Daughter {sup 253}Fm

    SciTech Connect

    Asai, M.; Tsukada, K.; Ichikawa, S.; Nagame, Y.; Nishinaka, I.; Akiyama, K.; Sakama, M.; Ishii, T.; Osa, A.; Oura, Y.; Sueki, K.; Shibata, M.

    2005-09-02

    {alpha}-{gamma} and {alpha}-electron coincidence spectroscopy for a short-lived heavy actinide nucleus {sup 257}No (T{sub 1/2}=24.5 s) has been performed using a gas-jet transport system and an on-line isotope separator. Spin-parities of excited states in {sup 253}Fm fed by the {alpha} decay of {sup 257}No have been identified on the basis of the measured internal conversion coefficients. The {nu}3/2{sup +}[622] configuration has been assigned to the ground state of {sup 257}No as well as to the 124.1 keV level in {sup 253}Fm. It was found that the ground-state configuration of {sup 257}No is different from that of lighter N=155 isotones.

  8. 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.

  9. L-shell X-ray production cross sections induced by protons and alpha-particles in the 0.7-2.0 MeV/amu range for Ru and Ag

    NASA Astrophysics Data System (ADS)

    Bertol, A. P. L.; Trincavelli, J.; Hinrichs, R.; Vasconcellos, M. A. Z.

    2014-01-01

    The X-ray emissions induced by protons and alpha-particles of the elements Ag and Ru were measured on mono-elemental thin films. L-shell X-ray production cross sections were obtained for the three L-subshells, considering absorption corrections. The Ag X-ray production cross sections agree with experimental data of other authors and with theoretical models, and were used to endorse the quality of the experimental values for Ru, that were not found in the literature.

  10. 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

  11. MODELING AEROSOL FORMATION FROM ALPHA-PINENE + NOX IN THE PRESENCE OF NATURAL SUNLIGHT USING GAS PHASE KINETICS AND GAS-PARTICLE PARTITIONING THEORY. (R826771)

    EPA Science Inventory

    A kinetic mechanism was used to link and model the gas-phase reactions and
    aerosol accumulation resulting from src="/ncer/pubs/images/alpha.gif">-pinene reactions in the presence of sunlight,
    ozone (O3), and oxides of nitrogen
    (NO

  12. Recoil Decay Tagging Study Of Transitional Proton Emitters 145,146,147Tm

    SciTech Connect

    Robinson, A.P.; Woods, P.J.; Davinson, T.; Liu, Z.; Davids, C.N.; Seweryniak, D.; Carpenter, M.P.; Hammond, N.; Janssens, R.V.F.; Mukherjee, G.; Sinha, S.; Blank, B.; Freeman, S.J.; Hoteling, N.; Shergur, J.; Walters, W.B.; Scholey, C.; Sonzogni, A.A.; Woehr, A.

    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.

  13. Search for Event Rate Modulation in XENON100 Electronic Recoil Data.

    PubMed

    Aprile, E; Aalbers, J; Agostini, F; Alfonsi, M; Anthony, M; Arazi, L; Arisaka, K; Arneodo, F; Balan, C; Barrow, P; Baudis, L; Bauermeister, B; Breur, P A; Brown, A; Brown, E; Bruenner, S; Bruno, G; Budnik, R; Bütikofer, L; Cardoso, J M R; Cervantes, M; Coderre, D; Colijn, A P; Contreras, H; Cussonneau, J P; Decowski, M P; de Perio, P; Di Giovanni, A; Duchovni, E; Fattori, S; Ferella, A D; Fieguth, A; Fulgione, W; Gao, F; Garbini, M; Geis, C; Goetzke, L W; Grignon, C; Gross, E; Hampel, W; Hasterok, C; Itay, R; Kaether, F; Kaminsky, B; Kessler, G; Kish, A; Landsman, H; Lang, R F; Le Calloch, M; Lellouch, D; Levinson, L; Levy, C; Lindemann, S; Lindner, M; Lopes, J A M; Lyashenko, A; Macmullin, S; Marrodán Undagoitia, T; Masbou, J; Massoli, F V; Mayani, D; Melgarejo Fernandez, A J; Meng, Y; Messina, M; Micheneau, K; Miguez, B; Molinario, A; Murra, M; Naganoma, J; Ni, K; Oberlack, U; Orrigo, S E A; Pakarha, P; Persiani, R; Piastra, F; Pienaar, J; Plante, G; Priel, N; Rauch, L; Reichard, S; Reuter, C; Rizzo, A; Rosendahl, S; Dos Santos, J M F; Sartorelli, G; Schindler, S; Schreiner, J; Schumann, M; Scotto Lavina, L; Selvi, M; Shagin, P; Simgen, H; Teymourian, A; Thers, D; Tiseni, A; Trinchero, G; Tunnell, C; Wall, R; Wang, H; Weber, M; Weinheimer, C; Zhang, Y

    2015-08-28

    We have searched for periodic variations of the electronic recoil event rate in the (2-6) keV energy range recorded between February 2011 and March 2012 with the XENON100 detector, adding up to 224.6 live days in total. Following a detailed study to establish the stability of the detector and its background contributions during this run, we performed an unbinned profile likelihood analysis to identify any periodicity up to 500 days. We find a global significance of less than 1? for all periods, suggesting no statistically significant modulation in the data. While the local significance for an annual modulation is 2.8?, the analysis of a multiple-scatter control sample and the phase of the modulation disfavor a dark matter interpretation. The DAMA/LIBRA annual modulation interpreted as a dark matter signature with axial-vector coupling of weakly interacting massive particles to electrons is excluded at 4.8?. PMID:26371638

  14. Search for Event Rate Modulation in XENON100 Electronic Recoil Data

    NASA Astrophysics Data System (ADS)

    Aprile, E.; Aalbers, J.; Agostini, F.; Alfonsi, M.; Anthony, M.; Arazi, L.; Arisaka, K.; Arneodo, F.; Balan, C.; Barrow, P.; Baudis, L.; Bauermeister, B.; Breur, P. A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Cardoso, J. M. R.; Cervantes, M.; Coderre, D.; Colijn, A. P.; Contreras, H.; Cussonneau, J. P.; Decowski, M. P.; de Perio, P.; di Giovanni, A.; Duchovni, E.; Fattori, S.; Ferella, A. D.; Fieguth, A.; Fulgione, W.; Gao, F.; Garbini, M.; Geis, C.; Goetzke, L. W.; Grignon, C.; Gross, E.; Hampel, W.; Hasterok, C.; Itay, R.; Kaether, F.; Kaminsky, B.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Le Calloch, M.; Lellouch, D.; Levinson, L.; Levy, C.; Lindemann, S.; Lindner, M.; Lopes, J. A. M.; Lyashenko, A.; Macmullin, S.; Marrodán Undagoitia, T.; Masbou, J.; Massoli, F. V.; Mayani, D.; Melgarejo Fernandez, A. J.; Meng, Y.; Messina, M.; Micheneau, K.; Miguez, B.; Molinario, A.; Murra, M.; Naganoma, J.; Ni, K.; Oberlack, U.; Orrigo, S. E. A.; Pakarha, P.; Persiani, R.; Piastra, F.; Pienaar, J.; Plante, G.; Priel, N.; Rauch, L.; Reichard, S.; Reuter, C.; Rizzo, A.; Rosendahl, S.; Dos Santos, J. M. F.; Sartorelli, G.; Schindler, S.; Schreiner, J.; Schumann, M.; Scotto Lavina, L.; Selvi, M.; Shagin, P.; Simgen, H.; Teymourian, A.; Thers, D.; Tiseni, A.; Trinchero, G.; Tunnell, C.; Wall, R.; Wang, H.; Weber, M.; Weinheimer, C.; Zhang, Y.; Xenon Collaboration

    2015-08-01

    We have searched for periodic variations of the electronic recoil event rate in the (2-6) keV energy range recorded between February 2011 and March 2012 with the XENON100 detector, adding up to 224.6 live days in total. Following a detailed study to establish the stability of the detector and its background contributions during this run, we performed an unbinned profile likelihood analysis to identify any periodicity up to 500 days. We find a global significance of less than 1 ? for all periods, suggesting no statistically significant modulation in the data. While the local significance for an annual modulation is 2.8 ? , the analysis of a multiple-scatter control sample and the phase of the modulation disfavor a dark matter interpretation. The DAMA/LIBRA annual modulation interpreted as a dark matter signature with axial-vector coupling of weakly interacting massive particles to electrons is excluded at 4.8 ? .

  15. The new vacuum-mode recoil separator MARA at JYFL

    NASA Astrophysics Data System (ADS)

    Sarén, J.; Uusitalo, J.; Leino, M.; Greenlees, P. T.; Jakobsson, U.; Jones, P.; Julin, R.; Juutinen, S.; Ketelhut, S.; Nyman, M.; Peura, P.; Rahkila, P.; Scholey, C.; Sorri, J.

    2008-10-01

    A new vacuum-mode recoil separator MARA (Mass Analysing Recoil Apparatus) is under design and construction at the Department of Physics in the University of Jyväskylä. The separator is intended to separate reaction products from the primary beam in mass region below A = 150 . The ion-optical configuration of the separator will be QQQDEDM, where a magnetic quadrupole (Q) triplet is followed by an electrostatic deflector (DE) and a magnetic dipole (DM). The total length of MARA will be less than 7.0 m and the first order resolving power more than 250 for a beam spot size of 2 mm. In this contribution the main properties of MARA are given and results from simulations are shown.

  16. Gravitational wave recoil in Robinson-Trautman spacetimes

    NASA Astrophysics Data System (ADS)

    Macedo, Rodrigo P.; Saa, Alberto

    2008-11-01

    We consider the gravitational recoil due to nonreflection-symmetric gravitational wave emission in the context of axisymmetric Robinson-Trautman spacetimes. We show that regular initial data evolve generically into a final configuration corresponding to a Schwarzschild black hole moving with constant speed. For the case of (reflection-)symmetric initial configurations, the mass of the remnant black hole and the total energy radiated away are completely determined by the initial data, allowing us to obtain analytical expressions for some recent numerical results that have appeared in the literature. Moreover, by using the Galerkin spectral method to analyze the nonlinear regime of the Robinson-Trautman equations, we show that the recoil velocity can be estimated with good accuracy from some asymmetry measures (namely the first odd moments) of the initial data. The extension for the nonaxisymmetric case and the implications of our results for realistic situations involving head-on collision of two black holes are also discussed.

  17. Recoiling supermassive black holes: a search in the nearby universe

    SciTech Connect

    Lena, D.; Robinson, A.; Axon, D. J.; Merritt, D.; Marconi, A.; Capetti, A.; Batcheldor, D.

    2014-11-10

    The coalescence of a binary black hole can be accompanied by a large gravitational recoil due to anisotropic emission of gravitational waves. A recoiling supermassive black hole (SBH) can subsequently undergo long-lived oscillations in the potential well of its host galaxy, suggesting that offset SBHs may be common in the cores of massive ellipticals. We have analyzed Hubble Space Telescope archival images of 14 nearby core ellipticals, finding evidence for small (? 10 pc) displacements between the active galactic nucleus (AGN; the location of the SBH) and the center of the galaxy (the mean photocenter) in 10 of them. Excluding objects that may be affected by large-scale isophotal asymmetries, we consider six galaxies to have detected displacements, including M87, where a displacement was previously reported by Batcheldor et al. In individual objects, these displacements can be attributed to residual gravitational recoil oscillations following a major or minor merger within the last few gigayears. For plausible merger rates, however, there is a high probability of larger displacements than those observed, if SBH coalescence took place in these galaxies. Remarkably, the AGN-photocenter displacements are approximately aligned with the radio source axis in four of the six galaxies with displacements, including three of the four having relatively powerful kiloparsec-scale jets. This suggests intrinsic asymmetries in radio jet power as a possible displacement mechanism, although approximate alignments are also expected for gravitational recoil. Orbital motion in SBH binaries and interactions with massive perturbers can produce the observed displacement amplitudes but do not offer a ready explanation for the alignments.

  18. Time-of-flight direct recoil ion scattering spectrometer

    DOEpatents

    Krauss, Alan R. (Naperville, IL); Gruen, Dieter M. (Downers Grove, IL); Lamich, George J. (Orland Park, IL)

    1994-01-01

    A time of flight direct recoil and ion scattering spectrometer beam line (10). The beam line (10) includes an ion source (12) which injects ions into pulse deflection regions (14) and (16) separated by a drift space (18). A final optics stage includes an ion lens and deflection plate assembly (22). 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 (14) and (16).

  19. 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.

  20. 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 ...

  1. 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).

  2. Anatomy of the binary black hole recoil: A multipolar analysis

    E-print Network

    Jeremy D. Schnittman; Alessandra Buonanno; James R. van Meter; John G. Baker; William D. Boggs; Joan Centrella; Bernard J. Kelly; Sean T. McWilliams

    2007-12-20

    We present a multipolar analysis of the gravitational recoil computed in recent numerical simulations of binary black hole (BH) coalescence, for both unequal masses and non-zero, non-precessing spins. We show that multipole moments up to and including l=4 are sufficient to accurately reproduce the final recoil velocity (within ~2%) and that only a few dominant modes contribute significantly to it (within ~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 formulae 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 (QNMs). 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 help explain the remarkable difference between the amplitudes of planar and non-planar kicks for equal-mass spinning black holes.

  3. 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.

  4. The recoil proton polarization in. pi. p elastic scattering

    SciTech Connect

    Seftor, C.J.

    1988-09-01

    The polarization of the recoil proton for ..pi../sup +/p and ..pi../sup -/p elastic scattering has been measured for various angles at 547 MeV/c and 625 MeV/c by a collaboration involving The George Washington University; the University of California, Los Angeles; and Abilene Christian University. The experiment was performed at the P/sup 3/ East experimental area of the Los Alamos Meson Physics Facility. Beam intensities varied from 0.4 to 1.0 x 10/sup 7/ ..pi../sup -/'s/sec and from 3.0 to 10.0 x 10/sup 7/ ..pi../sup +/'s/sec. The beam spot size at the target was 1 cm in the horizontal direction by 2.5 cm in the vertical direction. A liquid-hydrogen target was used in a flask 5.7 cm in diameter and 10 cm high. The scattered pion and recoil proton were detected in coincidence using the Large Acceptance Spectrometer (LAS) to detect and momentum analyze the pions and the JANUS recoil proton polarimeter to detect and measure the polarization of the protons. Results from this experiment are compared with previous measurements of the polarization, with analyzing power data previously taken by this group, and to partial-wave analysis predictions. 12 refs., 53 figs., 18 tabs.

  5. Investigation of the effective atomic numbers of dosimetric materials for electrons, protons and alpha particles using a direct method in the energy region 10 keV-1 GeV: a comparative study.

    PubMed

    Kurudirek, Murat; Aksakal, O?uz; Akku?, Tuba

    2015-11-01

    A direct method has been used for the first time, to compute effective atomic numbers (Z eff) of water, air, human tissues, and some organic and inorganic compounds, for total electron proton and alpha particle interaction in the energy region 10 keV-1 GeV. The obtained values for Z eff were then compared to those obtained using an interpolation procedure. In general, good agreement has been observed for electrons, and the difference (%) in Z eff between the results of the direct and the interpolation method was found to be <10 % for all materials, in the energy range from 10 keV to 1 MeV. More specifically, results of the two methods were found to agree well (Dif. <10 %) for air, calcium fluoride, kapton polyimide film, paraffin wax and plastic scintillator in the entire energy region with respect to the total electron interaction. On the other hand, values for Z eff calculated using both methods for protons and alpha particles generally agree with each other in the high-energy region above 10 MeV. PMID:26082026

  6. 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.

  7. Alpha-1 Antitrypsin Deficiency

    MedlinePLUS

    ... Liver > 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 ...

  8. 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.; Pavan, John R; Stone, Nicholas J; Stuchberry, A. E.; Baktash, Cyrus; Beene, James R; Benczer-Koller, N.; Bingham, Carrol R; Dupak, J.; Galindo-Uribarri, Alfredo {nmn}; Gross, Carl J; Kumbartzki, Gerfried J; Radford, David C; Stone, Jirina R; Timlin, Claire L; Yu, Chang-Hong; Zamfir, Nicolae Victor

    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).

  9. Nuclear recoil corrections to the $2p_\\frac{3}{2}$ state energy of hydrogen-like and high $Z$ lithium like atoms in all orders in $?Z$

    E-print Network

    A. N. Artemyev; V. M. Shabaev; V. A. Yerokhin

    1995-10-16

    The relativistic nuclear recoil corrections to the energy of the $2p_{\\frac{3}{2}}$ state of hydrogen-like and the $(1s)^{2}2p_{\\frac{3}{2}}$ state of high $Z$ lithium-like atoms in all orders in $\\alpha Z$ are calculated. The calculations are carried out using the B-spline method for the Dirac equation. For low $Z$ the results of the calculation are in good agreement with the $\\alpha Z$ -expansion results. It is found that the total nuclear recoil contribution to the energy of the $(1s)^{2}2p_{\\frac{3}{2}}- (1s)^{2}2s$ transition in lithium-like uranium constitutes $-0.09\\,eV$.

  10. Ionization Yield from Nuclear Recoils in Liquid-Xenon Dark Matter Detection

    E-print Network

    Wei Mu; Xiangdong Ji

    2013-10-08

    The ionization yield in the two-phase liquid xenon dark-matter detector has been studied in keV nuclear-recoil energy region. The newly-obtained nuclear quenching as well as the recently-measured average energy required to produce an electron-ion pair are used to calculate the total electric charges produced. To estimate the fraction of the electron charges collected, the Thomas-Imel model is generalized to describing the field dependence for nuclear recoils in liquid xenon. With free parameters fitted to experiment measured 56.5 keV nuclear recoils, the energy dependence of ionization yield for nuclear recoils is predicted, which increases with the decreasing of the recoiling energy and reaches the maximum value at 2~3 keV. This prediction agrees well with existing data and may help to lower the energy detection threshold for nuclear recoils to ~1 keV.

  11. Multipurpose Radiation Resistant Semiconductor Detectors for Alpha, Neutron & Low Energy Gamma Ray Measurements at High Temperatures in High-Intensity Gamma Ray

    SciTech Connect

    Ruddy, Frank H.

    2005-06-01

    Work scheduled under year two of DOE Grant DE-FG02-04ER63734 is on schedule and all year-two milestones have or will be met. Results to date demonstrate that unprecedented silicon carbide (SiC) energy resolution has been obtained, and that SiC detectors may achieve energy resolution that exceeds that obtainable with the best silicon alpha spectrometers. Fast-neutron energy spectrometry measurements indicate that recoil-ion energy spectrometry should be possible with SiC detectors. Furthermore, SiC detectors have been demonstrated to perform well even after gamma-ray exposures of 1.E09 Rad. This result and the previously demonstrated capability of SiC detectors to operate in elevated-temperature environments are very promising for potential DOE EMSP applications. A new class of multipurpose, radiation-resistant semiconductor detectors that can be used in elevated-temperature and high-radiation environments is being developed under this grant. These detectors, based on silicon carbide (SiC) semiconductor are designed to have larger active volumes than previously available SiC detectors, and are being tested for their response to alpha particles, X-rays and low energy gamma rays, and fast neutrons. Specifically, SiC radiation detectors with larger areas and 100-micrometer thick active regions have been designed and manufactured according to detector-design specifications. Detectors based on a Schottky diode design were specified in order to minimize the effects of the detector entrance window on alpha particle measurements. During manufacture of the Schottky diodes, the manufacturer also provided a set of large-volume SiC p-i-n diodes for testing Extensive alpha particle measurements have been carried out to test and quantify the response of the SiC Schottky diodes. Exposures to 148-Gd, 213-Po, 217-At, 221-Fr, 225-Ac, 237-Np, 238-Pu, 240-Pu, and 242-Pu sources were used to obtain detailed alpha response data in the alpha energy range from 3182.787 keV to 8375.9 keV. The 148-Gd, 213-Po, 217-At, and 221-Fr sources provide energy-separated, mono-energetic alpha particle peaks which can be analyzed to provide detailed information on the energy response characteristics of the detectors.

  12. Recoil ion charge state distribution following the beta(sup +) decay of {sup 21}Na

    SciTech Connect

    Scielzo, Nicholas D.; Freedman, Stuart J.; Fujikawa, Brian K.; Vetter, Paul A.

    2003-01-03

    The charge state distribution following the positron decay of 21Na has been measured, with a larger than expected fraction of the daughter 21Ne in positive charge states. No dependence on either the positron or recoil nucleus energy is observed. The data is compared to a simple model based on the sudden approximation. Calculations suggest a small but important contribution from recoil ionization has important consequences for precision beta decay correlation experiments detecting recoil ions.

  13. Alpha-Particle-Induced Complex Chromosome Exchanges Transmitted through Extra-Thymic Lymphopoiesis In Vitro Show Evidence of Emerging Genomic Instability

    PubMed Central

    Sumption, Natalia; Goodhead, Dudley T.; Anderson, Rhona M.

    2015-01-01

    Human exposure to high-linear energy transfer ?-particles includes environmental (e.g. radon gas and its decay progeny), medical (e.g. radiopharmaceuticals) and occupational (nuclear industry) sources. The associated health risks of ?-particle exposure for lung cancer are well documented however the risk estimates for leukaemia remain uncertain. To further our understanding of ?-particle effects in target cells for leukaemogenesis and also to seek general markers of individual exposure to ?-particles, this study assessed the transmission of chromosomal damage initially-induced in human haemopoietic stem and progenitor cells after exposure to high-LET ?-particles. Cells surviving exposure were differentiated into mature T-cells by extra-thymic T-cell differentiation in vitro. Multiplex fluorescence in situ hybridisation (M-FISH) analysis of naïve T-cell populations showed the occurrence of stable (clonal) complex chromosome aberrations consistent with those that are characteristically induced in spherical cells by the traversal of a single ?-particle track. Additionally, complex chromosome exchanges were observed in the progeny of irradiated mature T-cell populations. In addition to this, newly arising de novo chromosome aberrations were detected in cells which possessed clonal markers of ?-particle exposure and also in cells which did not show any evidence of previous exposure, suggesting ongoing genomic instability in these populations. Our findings support the usefulness and reliability of employing complex chromosome exchanges as indicators of past or ongoing exposure to high-LET radiation and demonstrate the potential applicability to evaluate health risks associated with ?-particle exposure. PMID:26252014

  14. Synthesis of phosphorus-32 labeled compounds using recoil atoms. II. Synthesis of o,o-diakyl-s-alkylthio (/sup 32/P) phosphates and study of kinetics of thiol group substitution

    SciTech Connect

    Makarov, A.M.; Genkina, G.K.; Mastryukova, T.A.

    1985-07-01

    The authors synthesize O,O-Dialkyl-S-alkylthio ( /sup 32/ P) phosphates in a state without carrier by reactions of phosphorous-32 recoil atoms, formed in the reaction /sup 35/Cl (n, alpha) /sup 32/P in the CCl/sub 4/-alkanol-alkanethiol system. Using radiochromatography, they study the kinetics of substitution of the thiol group in O,Odibutyl-S-butylthio ( /sup 32/ P) phosphate. They determine the hydrolysis and transesterification constants.

  15. Revealing Compressed Stops Using High-Momentum Recoils

    E-print Network

    Sebastian Macaluso; Michael Park; David Shih; Brock Tweedie

    2015-06-25

    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 MET measurements, we estimate that Run 2 will already start to close the gap in exclusion sensitivity with the first few 10s of inverse-fb. By 300/fb, exclusion sensitivity may extend from stop masses of 550 GeV on the high side down to below 200 GeV on the low side, approaching the "stealth" point at m(stop) = m(top) and potentially overlapping with limits from top pair cross section and spin correlation measurements.

  16. Measurements of Scintillation Efficiency and Pulse-Shape for Low Energy Recoils in Liquid Xenon

    E-print Network

    D. Akimov; A. Bewick; D. Davidge; J. Dawson; A. S. Howard; I. Ivaniouchenkov; W. G. Jones; M. Joshi; V. A. Kudryavtsev; T. B. Lawson; V. Lebedenko; M. J. Lehner; P. K. Lightfoot; I. Liubarsky; R. Luscher; J. E. McMillan; C. D. Peak; J. J. Quenby; N. J. C. Spooner; T. J. Sumner; D. R. Tovey; C. K. Ward

    2001-06-08

    Results of observations of low energy nuclear and electron recoil events in liquid xenon scintillator detectors are given. The relative scintillation efficiency for nuclear recoils is 0.22 +/- 0.01 in the recoil energy range 40 keV - 70 keV. Under the assumption of a single dominant decay component to the scintillation pulse-shape the log-normal mean parameter T0 of the maximum likelihood estimator of the decay time constant for 6 keV pulse-shapes are found to be well fitted by single exponential functions although some evidence is found for a double exponential form for the nuclear recoil pulse-shape.

  17. Long-range alpha detector (LRAD)

    SciTech Connect

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

    1991-01-01

    Historically, alpha detectors have been limited by the very short range of alpha particles in air and by relatively poor sensitivity, even if the particles are intercepted. Of necessity, these detectors are operated in a vacuum or in close proximity to the source if reasonable efficiency is desired. In our new long-range alpha detector (LRAD), alpha particles interact with the ambient air, producing ionization in the air at the rate of about 30,000 ion pairs per MeV of alpha energy. These charges can be transported over significant distances (several meters) in a moving current of air generated by a small fan. An ion chamber located in front of the fan measures the current carried by the moving ions. The LRAD-based monitor is more sensitive and more thorough than conventional monitors. We present current LRAD sensitivity limits and results, practical monitor designs, and proposed uses for LRAD monitors. 4 refs., 7 figs.

  18. Secondary organic aerosol formation from alpha-pinene and toluene: Laboratory studies examining the role of pre-existing particles, relative humidity and oxidant type

    NASA Astrophysics Data System (ADS)

    Cui, Tianqu

    Secondary organic aerosol (SOA) is a major fraction of fine particulate matter (PM2.5), thus impacting air quality and climate. In the first section of this thesis, experiments were performed to investigate SOA formation from both ozonolysis and hydroxyl radical (OH)-initiated oxidation (so-called photooxidation) of alpha-pinene under conditions with varying relative humidity (RH) and seed aerosol acidity at the UNC dual outdoor smog chamber facility. Formation of dimer esters was observed only in SOA derived from alpha-pinene ozonolysis with increased concentrations at high RH, indicating these compounds could serve as tracers for SOA enhanced by anthropogenic pollution. In the second section of this thesis, toluene photooxidation experiments in presence of nitric oxide were conducted to examine the effect of the pre-existing titanium dioxide (TiO2) seed aerosol, as an instance of engineered metal oxide nanomaterials, considering their unique photocatalytic properties. Results indicate that TiO2 aerosol enhanced and accelerated SOA formation from toluene.

  19. Collective atomic recoil lasing including friction and diffusion effects

    SciTech Connect

    Robb, G.R.M.; Piovella, N.; Ferraro, A.; Bonifacio, R.; Courteille, Ph.W.; Zimmermann, C.

    2004-04-01

    We extend the collective atomic recoil lasing (CARL) model including the effects of friction and diffusion forces acting on the atoms due to the presence of optical molasses fields. The results from this model are consistent with those from a recent experiment by Kruse et al. [ Phys. Rev. Lett. 91, 183601 (2003) ]. In particular, we obtain a threshold condition above which collective backscattering occurs. Using a nonlinear analysis we show that the backscattered field and the bunching evolve to a steady state, in contrast to the nonstationary behavior of the standard CARL model. For a proper choice of the parameters, this steady state can be superfluorescent.

  20. Is CHF triggered by the vapor recoil effect?

    E-print Network

    Nikolayev, Vadim S; Chatain, D

    2007-01-01

    This paper deals with the triggering mechanism of the boiling crisis, a transition from nucleate to film boiling. We observe the boiling crisis in pool saturated boiling experimentally at nearly critical pressure to take advantage of the slowness of the bubble growth and of the smallness of the Critical Heat Flux (CHF) that defines the transition point. Such experiments require the reduced gravity conditions. Close to the CHF, the slow growth of the individual dry spots and their subsequent fusion on the transparent heater are observed through the latter. As discussed in the paper, these observations are consistent with numerical results obtained with the vapor recoil model of the boiling crisis.

  1. Search for $?$-mesic nuclei in recoil-free transfer reaction

    E-print Network

    The COSY-GEM Collaboration; :; A. Budzanowski

    2008-12-22

    We have studied the reaction $p+{^{27}Al}\\to {^3{He}}+p+\\pi^-+X$ at recoil-free kinematics. An $\\eta$ meson possibly produced in this reaction would be thus almost at rest in the laboratory system and could therefore be bound with high probability, if nuclear $\\eta$ states exist. The decay of such a state through the $N^*(1535)$ resonance would lead to a proton-$\\pi^-$ pair emitted in opposite directions. For these conditions we find some indication of such a bound state. An upper limit of $\\approx$ 0.5 nb is found.

  2. B -> D* l nu at zero recoil: an update

    SciTech Connect

    Bailey, Jon A.; Bazavov, A.; Bernard, C.; Bouchard, C.M.; DeTar, C.; El-Khadra, A.X.; Freeland, E.D.; Gamiz, E.; Gottlieb, Steven; Heller, U.M.; Hetrick, J.E.

    2010-11-01

    We present an update of our calculation of the form factor for {bar B} {yields} D*{ell}{bar {nu}} at zero recoil, with higher statistics and finer lattices. As before, we use the Fermilab action for b and c quarks, the asqtad staggered action for light valence quarks, and the MILC ensembles for gluons and light quarks (Luescher-Weisz married to 2+1 rooted staggered sea quarks). In this update, we have reduced the total uncertainty on F(1) from 2.6% to 1.7%.

  3. Projectile paths corrected for recoil and air resistance

    NASA Astrophysics Data System (ADS)

    Kemp, H. R.

    1986-01-01

    The angle of projection of a bullet is not the same as the angle of the bore of the firearm just before firing. This is because recoil alters the direction of the barrel as the bullet moves along the barrel. Neither is the angle of projection of an arrow the same as the direction of the arrow just before it is projected. The difficulty in obtaining the angle of projection limits the value of the standard equation for trajectories relative to a horizontal plane. Furthermore, air resistance makes this equation unrealistic for all but short ranges.

  4. B -> D* l nu at zero recoil: an update

    E-print Network

    Jon A. Bailey; A. Bazavov; C. Bernard; C. M. Bouchard; C. DeTar; A. X. El-Khadra; E. D. Freeland; E. Gámiz; Steven Gottlieb; U. M. Heller; J. E. Hetrick; A. S. Kronfeld; J. Laiho; L. Levkova; P. B. Mackenzie; M. B. Oktay; J. N. Simone; R. Sugar; D. Toussaint; R. S. Van de Water

    2010-11-09

    We present an update of our calculation of the form factor for B -> D* l nu at zero recoil, with higher statistics and finer lattices. As before, we use the Fermilab action for b and c quarks, the asqtad staggered action for light valence quarks, and the MILC ensembles for gluons and light quarks (L\\"uscher-Weisz married to 2+1 rooted staggered sea quarks). In this update, we have reduced the total uncertainty on F(1) from 2.6% to 1.7%. At Lattice2010 we presented a still-blinded result, but this writeup includes the unblinded result from the September 2010 CKM workshop.

  5. Recoil proton distribution in high energy photoproduction processes

    E-print Network

    E. Bartos; E. A. Kuraev; Yu. P. Peresunko; E. A. Vinokurov

    2006-11-22

    For high energy linearly polarized photon--proton scattering we have calculated the azimuthal and polar angle distributions in inclusive on recoil proton experimental setup. We have taken into account the production of lepton and pseudoscalar meson charged pairs. The typical values of cross sections are of order of hundreds of picobarn. The size of polarization effects are of order of several percents. The results are generalized for the case of electroproduction processes on the proton at rest and for high energy proton production process on resting proton.

  6. Swelling induced by alpha decay in monazite and zirconolite ceramics: A XRD and TEM comparative study

    NASA Astrophysics Data System (ADS)

    Deschanels, X.; Seydoux-Guillaume, A. M.; Magnin, V.; Mesbah, A.; Tribet, M.; Moloney, M. P.; Serruys, Y.; Peuget, S.

    2014-05-01

    Zirconolite and monazite matrices are potential ceramics for the containment of actinides (Np, Cm, Am, Pu) which are produced over the reprocessing of spent nuclear fuel. Actinides decay mainly through the emission of alpha particles, which in turn causes most ceramics to undergo structural and textural changes (amorphization and/or swelling). In order to study the effects of alpha decays on the above mentioned ceramics two parallel approaches were set up. The first involved the use of an external irradiation source, Au, which allowed the deposited recoil energy to be simulated. The second was based on short-lived actinide doping with 238Pu, (i.e. an internal source), via the incorporation of plutonium oxide into both the monazite and zirconolite structures during synthesis. In both types of irradiation experiments, the zirconolite samples became amorphous at room temperature with damage close to 0.3 dpa; corresponding to a critical dose of 4 × 1018 ? g-1 (i.e. ?1.3 × 1021 keV cm-3). Both zirconolite samples also showed the same degree of macroscopic swelling at saturation (?6%), with ballistic processes being the predominant damaging effect. In the case of the monazite however, the macroscopic swelling and amorphization were dependent on the nature of the irradiation. Externally, (Au), irradiated samples became amorphous while also demonstrating a saturation swelling of up to 8%. In contrast to this, the swelling of the 238Pu doped samples was much smaller at ?1%. Also, unlike the externally (Au) irradiated monazite these 238Pu doped samples remained crystalline up to 7.5 × 1018 ? g-1 (0.8 dpa). XRD, TEM and swelling measurements were used to fully characterize and interpret this behavior. The low swelling and the conservation of the crystalline state of 238Pu doped monazite samples indicates that alpha annealing took place within this material.

  7. 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 massive particls (WIMPs). This thesis describes the development of silicon based cryogenic particle detectors designed to directly detect interactions with these WIMPs. These detectors are part of a new class

  8. Low Energy Electron and Nuclear Recoil Thresholds in the DRIFT-II Negative Ion TPC for 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. St. J. Murphy; 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

    2009-03-30

    Understanding the ability to measure and discriminate particle events at the lowest possible energy is an essential requirement in developing new experiments to search for weakly interacting massive particle (WIMP) dark matter. In this paper we detail an assessment of the potential sensitivity below 10 keV in the 1 m^3 DRIFT-II directionally sensitive, low pressure, negative ion time projection chamber (NITPC), based on event-by-event track reconstruction and calorimetry in the multiwire proportional chamber (MWPC) readout. By application of a digital smoothing polynomial it is shown that the detector is sensitive to sulfur and carbon recoils down to 2.9 and 1.9 keV respectively, and 1.2 keV for electron induced events. The energy sensitivity is demonstrated through the 5.9 keV gamma spectrum of 55Fe, where the energy resolution is sufficient to identify the escape peak. The effect a lower energy sensitivity on the WIMP exclusion limit is demonstrated. In addition to recoil direction reconstruction for WIMP searches this sensitivity suggests new prospects for applications also in KK axion searches.

  9. Nuclear isospin asymmetry in $\\alpha$ decays of heavy nuclei

    E-print Network

    Shin, Eunkyoung; Hyun, Chang Ho; Oh, Yongseok

    2015-01-01

    The effects of nuclear isospin asymmetry on $\\alpha$ decay lifetimes of heavy nuclei are investigated within various phenomenological models of nuclear potential for the $\\alpha$ particle. We consider the widely used simple square well potential and Woods-Saxon potential, and modify them by including an isospin asymmetry term. We then suggest a model for the potential of the $\\alpha$ particle motivated by a microscopic phenomenological approach of the Skyrme force model, which naturally introduce the isospin dependent form of the nuclear potential for the $\\alpha$ particle. The empirical $\\alpha$ decay lifetime formula of Viola and Seaborg is also modified to include isospin asymmetry effects. The obtained $\\alpha$ decay half-lives are in good agreement with the experimental data and we find that including the nuclear isospin effects somehow improves the theoretical results for $\\alpha$ decay half-lives. The implications of these results are discussed and the predictions on the $\\alpha$ decay lifetimes of sup...

  10. Reviews Book: Marie Curie and Her Daughters Resource: Cumulus Equipment: Alpha Particle Scattering Apparatus Equipment: 3D Magnetic Tube Equipment: National Grid Transmission Model Book: Einstein's Physics Equipment: Barton's Pendulums Equipment: Weather Station Web Watch

    NASA Astrophysics Data System (ADS)

    2013-09-01

    WE RECOMMEND Marie Curie and Her Daughters An insightful study of a resilient and ingenious family and their achievements Cumulus Simple to install and operate and with obvious teaching applications, this weather station 'donationware' is as easy to recommend as it is to use Alpha Particle Scattering Apparatus Good design and construction make for good results National Grid Transmission Model Despite its expense, this resource offers excellent value Einstein's Physics A vivid, accurate, compelling and rigorous treatment, but requiring an investment of time and thought WORTH A LOOK 3D Magnetic Tube Magnetic fields in three dimensions at a low cost Barton's Pendulums A neat, well-made and handy variant, but not a replacement for the more traditional version Weather Station Though not as robust or substantial as hoped for, this can be put to good use with the right software WEB WATCH An online experiment and worksheet are useful for teaching motor efficiency, a glance at CERN, and NASA's interesting information on the alpha-magnetic spectrometer and climate change

  11. Effects of Low-Dose Alpha-Particle Irradiation in Human Cells: The Role of Induced Genes and the Bystander Effect. Final Technical Report (9/15/1998-5/31/2005)

    SciTech Connect

    Little, John B.

    2013-09-17

    This grant was designed to examine the cellular and molecular mechanisms for the bystander effect of radiation (initially described in this laboratory) whereby damage signals are passed from irradiated to non-irradiated cells in a population. These signals induce genetic effects including DNA damage, mutations and chromosomal aberrations in the nonirradiated cells. Experiments were carried out in cultured mammalian cells, primarily human diploid cells, irradiated with alpha particles. This research resulted in 17 publications in the refereed literature and is described in the Progress Report where it is keyed to the publication list. This project was initiated at the Harvard School of Public Health (HSPH) and continued in collaboration with students/fellows at Colorado State University (CSU) and the New Jersey Medical School (NJMS).

  12. Alpha modification of Tokamak ballooning instabilities

    SciTech Connect

    Spong, D.A.; Leboeuf, J-N.; Holmes, J.A.; Christenson, P.J.

    1989-01-01

    This paper will discuss the high-n ballooning limit (drift resonant effects included in noncircular tokamak geometry) and the hybrid fluid-particle code (inhomogeneous, sheared slab geometry, full FLR alphas, linear and nonlinear).

  13. Precision spectroscopy by photon-recoil signal amplification.

    PubMed

    Wan, Yong; Gebert, Florian; Wübbena, Jannes B; Scharnhorst, Nils; Amairi, Sana; Leroux, Ian D; Hemmerling, Börge; Lörch, Niels; Hammerer, Klemens; Schmidt, Piet O

    2014-01-01

    Precision spectroscopy of atomic and molecular ions offers a window to new physics, but is typically limited to species with a cycling transition for laser cooling and detection. Quantum logic spectroscopy has overcome this limitation for species with long-lived excited states. Here we extend quantum logic spectroscopy to fast, dipole-allowed transitions and apply it to perform an absolute frequency measurement. We detect the absorption of photons by the spectroscopically investigated ion through the photon recoil imparted on a co-trapped ion of a different species, on which we can perform efficient quantum logic detection techniques. This amplifies the recoil signal from a few absorbed photons to thousands of fluorescence photons. We resolve the line centre of a dipole-allowed transition in (40)Ca(+) to 1/300 of its observed linewidth, rendering this measurement one of the most accurate of a broad transition. The simplicity and versatility of this approach enables spectroscopy of many previously inaccessible species. PMID:24477261

  14. Binary Black Holes: Spin Dynamics and Gravitational Recoil

    E-print Network

    Herrmann, Frank; Shoemaker, Deirdre M; Laguna, Pablo; Matzner, Richard A

    2007-01-01

    We present a study of spinning black hole binaries focusing on the spin dynamics of the individual black holes as well as on the gravitational recoil acquired by the black hole produced by the merger. We consider two series of initial spin orientations away from the binary orbital plane. In one of the series, the spins are anti-aligned; for the second series, one of the spins points away from the binary along the line separating the black holes. We find a remarkable agreement between the spin dynamics predicted at 2nd post-Newtonian order and those from numerical relativity. For each configuration, we compute the kick of the final black hole. We use the kick estimates from the series with anti-aligned spins to fit the parameters in the Kidder kick formula, and verify that the recoil along the direction of the orbital angular momentum is proportional to $\\sin\\theta$ and on the orbital plane to $\\cos\\theta$, with $\\theta$ the angle between the spin directions and the orbital angular momentum.

  15. Binary Black Holes: Spin Dynamics and Gravitational Recoil

    E-print Network

    Frank Herrmann; Ian Hinder; Deirdre M. Shoemaker; Pablo Laguna; Richard A. Matzner

    2007-09-17

    We present a study of spinning black hole binaries focusing on the spin dynamics of the individual black holes as well as on the gravitational recoil acquired by the black hole produced by the merger. We consider two series of initial spin orientations away from the binary orbital plane. In one of the series, the spins are anti-aligned; for the second series, one of the spins points away from the binary along the line separating the black holes. We find a remarkable agreement between the spin dynamics predicted at 2nd post-Newtonian order and those from numerical relativity. For each configuration, we compute the kick of the final black hole. We use the kick estimates from the series with anti-aligned spins to fit the parameters in the \\KKF{,} and verify that the recoil along the direction of the orbital angular momentum is $\\propto \\sin\\theta$ and on the orbital plane $\\propto \\cos\\theta$, with $\\theta$ the angle between the spin directions and the orbital angular momentum. We also find that the black hole spins can be well estimated by evaluating the isolated horizon spin on spheres of constant coordinate radius.

  16. The WITCH experiment: Acquiring the first recoil ion spectrum

    E-print Network

    V. Yu. Kozlov; M. Beck; S. Coeck; P. Delahaye; P. Friedag; M. Herbane; A. Herlert; I. S. Kraev; M. Tandecki; S. Van Gorp; F. Wauters; Ch. Weinheimer; F. Wenander; D. Zakoucky; N. Severijns

    2008-07-22

    The standard model of the electroweak interaction describes beta-decay in the well-known V-A form. Nevertheless, the most general Hamiltonian of a beta-decay includes also other possible interaction types, e.g. scalar (S) and tensor (T) contributions, which are not fully ruled out yet experimentally. The WITCH experiment aims to study a possible admixture of these exotic interaction types in nuclear beta-decay by a precise measurement of the shape of the recoil ion energy spectrum. The experimental set-up couples a double Penning trap system and a retardation spectrometer. The set-up is installed in ISOLDE/CERN and was recently shown to be fully operational. The current status of the experiment is presented together with the data acquired during the 2006 campaign, showing the first recoil ion energy spectrum obtained. The data taking procedure and corresponding data acquisition system are described in more detail. Several further technical improvements are briefly reviewed.

  17. Binary black holes: Spin dynamics and gravitational recoil

    NASA Astrophysics Data System (ADS)

    Herrmann, Frank; Hinder, Ian; Shoemaker, Deirdre M.; Laguna, Pablo; Matzner, Richard A.

    2007-10-01

    We present a study of spinning black hole binaries focusing on the spin dynamics of the individual black holes as well as on the gravitational recoil acquired by the black hole produced by the merger. We consider two series of initial spin orientations away from the binary orbital plane. In one of the series, the spins are antialigned; for the second series, one of the spins points away from the binary along the line separating the black holes. We find a remarkable agreement between the spin dynamics predicted at 2nd post-Newtonian order and those from numerical relativity. For each configuration, we compute the kick of the final black hole. We use the kick estimates from the series with antialigned spins to fit the parameters in the Kidder kick formula, and verify that the recoil in the direction of the orbital angular momentum is ?sin?? and on the orbital plane ?cos??, with ? the angle between the spin directions and the orbital angular momentum. We also find that the black hole spins can be well estimated by evaluating the isolated horizon spin on spheres of constant coordinate radius.

  18. Analyzing power of the {sup 40}Ca(p-vector,p{alpha}) reaction at 100 MeV

    SciTech Connect

    Neveling, R.; Buthelezi, Z.; Foertsch, S. V.; Lawrie, J. J.; Steyn, G. F.; Smit, F. D.; Cowley, A. A.; Fujita, H.; Hillhouse, G. C.; Wyngaardt, S. M.; Botha, N. T.; Mudau, L.; Ntshangase, S. S.

    2008-03-15

    Analyzing powers have been measured for the {sup 40}Ca(p-vector,p{alpha}){sup 36}Ar reaction at an incident energy of 100 MeV for coplanar scattering angles corresponding to zero recoil momentum of the residual nucleus. Predictions based on the distorted wave impulse approximation fail to reproduce the data.

  19. Detection Efficiency of a ToF Spectrometer from Heavy-Ion Elastic Recoil Detection

    SciTech Connect

    Barbara, E. de; Marti, G. V.; Capurro, O. A.; Fimiani, L.; Mingolla, M. G.; Negri, A. E.; Arazi, A.; Figueira, J. M.; Pacheco, A. J.; Martinez Heimann, D.; Carnelli, P. F. F.; Fernandez Niello, J. O.

    2010-08-04

    The detection efficiency of a time-of-flight system based on two micro-channel plates (MCP) time zero detectors plus a conventional silicon surface barrier detector was obtained from heavy ion elastic recoil measurements (this ToF spectrometer is mainly devoted to measurements of total fusion cross section of weakly bound projectiles on different mass-targets systems). In this work we have used beams of {sup 7}Li, {sup 16}O, {sup 32}S and {sup 35}Cl to study the mass region of interest for its application to measurements fusion cross sections in the {sup 6,7}Li+{sup 27}Al systems at energies around and above the Coulomb barrier (0.8V{sub B{<=}}E{<=}2.0V{sub B}). As the efficiency of a ToF spectrometer is strongly dependent on the energy and mass of the detected particles, we have covered a wide range of the scattered particle energies with a high degree of accuracy at the lowest energies. The different experimental efficiency curves obtained in that way were compared with theoretical electronic stopping power curves on carbon foils and were applied.

  20. Analysis of the low-energy electron-recoil spectrum of the CDMS experiment

    NASA Astrophysics Data System (ADS)

    Ahmed, Z.; Akerib, D. S.; Arrenberg, S.; Bailey, C. N.; Balakishiyeva, D.; Baudis, L.; Bauer, D. A.; Beaty, J.; Brink, P. L.; Bruch, T.; Bunker, R.; Cabrera, B.; Caldwell, D. O.; Cooley, J.; Cushman, P.; Dejongh, F.; Dragowsky, M. R.; Duong, L.; Figueroa-Feliciano, E.; Filippini, J.; Fritts, M.; Golwala, S. R.; Grant, D. R.; Hall, J.; Hennings-Yeomans, R.; Hertel, S.; Holmgren, D.; Hsu, L.; Huber, M. E.; Kamaev, O.; Kiveni, M.; Kos, M.; Leman, S. W.; Mahapatra, R.; Mandic, V.; Moore, D.; McCarthy, K. A.; Mirabolfathi, N.; Nelson, H.; Ogburn, R. W.; Pyle, M.; Qiu, X.; Ramberg, E.; Rau, W.; Reisetter, A.; Saab, T.; Sadoulet, B.; Sander, J.; Schnee, R. W.; Seitz, D. N.; Serfass, B.; Sundqvist, K. M.; Wang, G.; Wikus, P.; Yellin, S.; Yoo, J.; Young, B. A.

    2010-02-01

    We report on the analysis of the low-energy electron-recoil spectrum from the CDMS II experiment using data with an exposure of 443.2 kg-days. The analysis provides details on the observed counting rate and possible background sources in the energy range of 2-8.5 keV. We find no significant excess of a peaked contribution to the total counting rate above the background model, and compare this observation to the recent DAMA results. In the framework of a conversion of a dark matter particle into electromagnetic energy, our 90% confidence level upper limit of 0.246events/kg/day at 3.15 keV is lower than the total rate above background observed by DAMA. In absence of any specific particle physics model to provide the scaling in cross section between NaI and Ge, we assume a Z2 scaling. With this assumption the observed rate in DAMA remains higher than the upper limit in CDMS. Under the conservative assumption that the modulation amplitude is 6% of the total rate we obtain upper limits on the modulation amplitude a factor of ˜2 lower than observed by DAMA, constraining some possible interpretations of this modulation.