Science.gov

Sample records for 50-130 mev range

  1. Ultrabroadband 50-130 THz pulses generated via phase-matcheddifference frequency mixing in LiIO3

    SciTech Connect

    Zentgraf, Thomas; Huber, Rupert; Nielsen, Nils C.; Chemla, DanielS.; Kaindl, Robert A.

    2006-10-10

    We report the generation of ultrabroadband pulses spanningthe 50-130 THz frequency range via phase-matched difference frequencymixing within the broad spectrum of sub-10 fs pulses in LiIO_3. Modelcalculations reproduce the octave-spanning spectra and predict few-cycleTHz pulse durations less than 20~;fs. The applicability of this scheme isdemonstrated with 9-fs pulses from a Ti:sapphire oscillator and with 7-fsamplified pulses from a hollow fiber compressor as pumpsources.

  2. Reconstruction of cogeneration plants equipped with LMZ R-50-130 steam turbines

    NASA Astrophysics Data System (ADS)

    Ermolaev, V. V.; Gudkov, N. N.; Shklyar, A. I.; Dudin, N. N.; Adamson, D. A.; Babiev, A. N.; Koshelev, S. A.; Solov'ev, A. K.; Miroshnichenko, S. A.

    2009-04-01

    The problems of how to use backpressure turbines underloaded for objective reasons at industrial cogeneration plants (CPs) are analyzed. The means of modernization of R-50-130 turbines implemented by the Teploenergoservis group of companies, which make it possible to meet the changed requirements for power and heat supply from a CP equipped with R-50-130 turbines and to increase productivity of CP fixed assets, are described.

  3. GRB spectra in the MeV range: hints from INTEGRAL

    SciTech Connect

    Bulik, Tomasz; Denis, Miroslaw; Marcinkowski, Radoslaw; Goldoni, Paolo; Laurent, Philip; Osuch, Lukasz

    2007-07-12

    INTEGRAL detects a large number of gamma-ray bursts outside of its field of view with the SPI ACS. Several of these bursts are also detected by IBIS. We present the results of the spectral analysis using the ISRGI, PICSIT and Compton mode data of several bursts. These bursts show very hard spectra with the high energy index reaching -2 above 1 MeV We show that there is a group of bursts with the peak energy Epeak in the MeV range. We discuss the implications of these findings for GLAST.

  4. Corrosion under argon irradiation of titanium in the low MeV range: A study coupling AFM and Spectroscopic Ellipsometry

    NASA Astrophysics Data System (ADS)

    Do, Ngoc-Long; Garcia-Caurel, Enric; Bérerd, Nicolas; Moncoffre, Nathalie; Gorse-Pomonti, Dominique

    2014-05-01

    This paper reports on a recent study of the corrosion under argon ion irradiation of titanium in the low MeV range (1-9 MeV), associating AFM and Spectroscopic Ellipsometry. Irradiation with MeV Arn+ (n = 1, 3) ions produces damages on the titanium surface. Large craters form on the oxidized titanium surface whose characteristics vary as a function of the argon energy between 2 and 9 MeV. The superficial oxide grows thicker under irradiation over the same energy range, especially near 3 MeV. It is suggested that collisions cascades play a significant role in the overall damage process.

  5. The Origin of the Cosmic Gamma-ray Background in the MeV Range

    NASA Astrophysics Data System (ADS)

    Ruiz-Lapuente, Pilar; The, Lih-Sin; Hartmann, Dieter H.; Ajello, Marco; Canal, Ramon; Röpke, Friedrich K.; Ohlmann, Sebastian T.; Hillebrandt, Wolfgang

    2016-04-01

    There has been much debate about the origin of the diffuse γ-ray background in the MeV range. At lower energies, AGNs and Seyfert galaxies can explain the background, but not above ≃0.3 MeV. Beyond ˜10 MeV blazars appear to account for the flux observed. That leaves an unexplained gap for which different candidates have been proposed, including annihilations of WIMPS. One candidate is Type Ia supernovae (SNe Ia). Early studies concluded that they were able to account for the γ-ray background in the gap, while later work attributed a significantly lower contribution to them. All those estimates were based on SN Ia explosion models that did not reflect the full 3D hydrodynamics of SN Ia explosions. In addition, new measurements obtained since 2010 have provided new, direct estimates of high-z SN Ia rates beyond z ˜ 2. We take into account these new advances to see the predicted contribution to the gamma-ray background. We use here a wide variety of explosion models and a plethora of new measurements of SN Ia rates. SNe Ia still fall short of the observed background. Only for a fit, which would imply ˜150% systematic error in detecting SN Ia events, do the theoretical predictions approach the observed fluxes. This fit is, however, at odds at the highest redshifts with recent SN Ia rate estimates. Other astrophysical sources such as flat-spectrum radio quasars do match the observed flux levels in the MeV regime, while SNe Ia make up to 30%-50% of the observed flux.

  6. Turbulent transport of MeV range cyclotron heated minorities as compared to alpha particles

    NASA Astrophysics Data System (ADS)

    Pusztai, István; Wilkie, George J.; Kazakov, Yevgen O.; Fülöp, Tünde

    2016-11-01

    We study the turbulent transport of an ion cyclotron resonance heated (ICRH), MeV range minority ion species in tokamak plasmas. Such highly energetic minorities, which can be produced in the three ion minority heating scheme (Kazakov et al (2015) Nucl. Fusion 55 032001), have been proposed to be used to experimentally study the confinement properties of fast ions without the generation of fusion alphas. We compare the turbulent transport properties of ICRH ions with that of fusion born alpha particles. Our theoretical predictions indicate that care must be taken when conclusions are drawn from experimental results: while the effect of turbulence on these particles is similar in terms of transport coefficients, differences in their distribution functions—ultimately their generation processes—make the resulting turbulent fluxes different.

  7. Spectroscopy in the 10 keV to 10 MeV range

    NASA Technical Reports Server (NTRS)

    Matteson, J. L.

    1981-01-01

    Spectral lines in the 10 keV to 1 MeV range carry information of fundamental importance on many astronomical objects. Since the lines are directly related to specific physical processes this information is model independent and gives the physical conditions in the objects. At the sensitivities achieved to date, approximately 0.0001 to 0.001 phsq cm. sec for steady sources and approximately 0.01 to 1 ph/sq cm sec for transient sources, lines were detected from the galactic center, gamma-ray bursts and transients, X-ray pulsators, the Crab pulsar and solar flares. Future instruments with a factor of approximately 100 sensitivity improvement will allow detailed spectroscopic study of these classes of objects as well as supernova remnants, active galaxies and the interstellar medium. This sensitivity improvement can be obtained through the use of detector technology already proven in balloon and satellite instruments.

  8. Systematics of Fission Cross Sections in the MeV Range

    SciTech Connect

    Westfall, Robert Michael; Wright, Richard Q

    2009-01-01

    Twenty-nine years ago J. W. Behrens published a paper on the systematics of fission cross sections (3 5 MeV average). His study included 57 isotopes of elements ranging from radium through einsteinium (Z = 88 to 99). A systematic trend was seen for the element range from protactinium through curium. For a given element, the fission cross section decreased as the A-number increased. Fission cross sections are considerably more accurate now than those available in 1980. The current study represents an update of the Behrens study. Data for 11 elements and 53 nuclides were used. Trends for both the (Z,A) variation and the (2Z N) correlation are demonstrated. The current study clearly shows that the trends are quite well represented by straight lines. The trend for the fission cross sections of a given element to decrease with increasing A-number is observed for values of A < 248. For A > 248 there is a trend for the fission cross section to increase with increasing A-number.

  9. Personal dose equivalent conversion coefficients for neutron fluence over the energy range of 20 to 250 MeV

    SciTech Connect

    Mclean, Thomas D; Justus, Alan L; Gadd, S Milan; Olsher, Richard H; Devine, Robert T

    2009-01-01

    Monte Carlo simulations were performed to extend existing neutron personal dose equivalent fluence-to-dose conversion coefficients to an energy of 250 MeV. Presently, conversion coefficients, H(p,slab)(10,alpha)/Phi, are given by ICRP-74 and ICRU-57 for a range of angles of radiation incidence (alpha = 0, 15, 30, 45, 60 and 75 degrees ) in the energy range from thermal to 20 MeV. Standard practice has been to base operational dose quantity calculations <20 MeV on the kerma approximation, which assumes that charged particle secondaries are locally deposited, or at least that charged particle equilibrium exists within the tally cell volume. However, with increasing neutron energy the kerma approximation may no longer be valid for some energetic secondaries such as protons. The Los Alamos Monte Carlo radiation transport code MCNPX was used for all absorbed dose calculations. Transport models and collision-based energy deposition tallies were used for neutron energies >20 MeV. Both light and heavy ions (HIs) (carbon, nitrogen and oxygen recoil nuclei) were transported down to a lower energy limit (1 keV for light ions and 5 MeV for HIs). Track energy below the limit was assumed to be locally deposited. For neutron tracks <20 MeV, kerma factors were used to obtain absorbed dose. Results are presented for a discrete set of angles of incidence on an ICRU tissue slab phantom.

  10. Measurements of galactic plane gamma ray emission in the energy range from 10 - 80 MeV

    NASA Technical Reports Server (NTRS)

    Bertsch, D. L.; Kniffen, D. A.

    1982-01-01

    A spark chamber gamma ray telescope was developed and flown to observe diffuse gamma ray emission from the central region of the galaxy. The extension of observations down to 10 MeV provides important new data indicating that the galactic diffuse gamma ray spectrum continues as a power law down to about 10 MeV, an observation in good agreement with recent theoretical predictions. Data from other experiments in the range from 100 keV to 10 MeV show a significant departure from the extension of the power-law fit to the medium energy observations reported here, possibly indicating that a different mechanism may be responsible for the emissions below and above a few MeV. The intensity of the spectrum above 10 MeV implies a galactic electron spectrum which is also very intense down to about 10 MeV. Electrons in this energy range cannot be observed in the solar cavity because of solar modulation effects. The galactic gamma ray data are compared with recent theoretical predictions.

  11. Measurements of galactic plane gamma-ray emission in the energy range 10-80 MeV

    NASA Technical Reports Server (NTRS)

    Bertsch, D. L.; Kniffen, D. A.

    1983-01-01

    A spark chamber gamma ray telescope was developed and flown to observe diffuse gamma ray emission from the central region of the galaxy. The extension of observations down to 10 MeV provides important new data indicating that the galactic diffuse gamma ray spectrum continues as a power law down to about 10 MeV, an observation in good agreement with recent theoretical predictions. Data from other experiments in the range from 100 keV to 10 MeV show a significant departure from the extension of the power-law fit to the medium energy observations reported here, possibly indicating that a different mechanism may be responsible for the emissions below and above a few MeV. The intensity of the spectrum above 10 MeV implies a galactic electron spectrum which is also very intense down to about 10 MeV. Electrons in this energy range cannot be observed in the solar cavity because of solar modulation effects. The galactic gamma ray data are compared with recent theoretical predictions. Previously announced in STAR as N83-17444

  12. Personal dose equivalent conversion coefficients for neutron fluence over the energy range of 20-250 MeV.

    PubMed

    Olsher, R H; McLean, T D; Justus, A L; Devine, R T; Gadd, M S

    2010-03-01

    Monte Carlo simulations were performed to extend existing neutron personal dose equivalent fluence-to-dose conversion coefficients to an energy of 250 MeV. Presently, conversion coefficients, H(p,slab)(10,alpha)/Phi, are given by ICRP-74 and ICRU-57 for a range of angles of radiation incidence (alpha = 0, 15, 30, 45, 60 and 75 degrees ) in the energy range from thermal to 20 MeV. Standard practice has been to base operational dose quantity calculations <20 MeV on the kerma approximation, which assumes that charged particle secondaries are locally deposited, or at least that charged particle equilibrium exists within the tally cell volume. However, with increasing neutron energy the kerma approximation may no longer be valid for some energetic secondaries such as protons. The Los Alamos Monte Carlo radiation transport code MCNPX was used for all absorbed dose calculations. Transport models and collision-based energy deposition tallies were used for neutron energies >20 MeV. Both light and heavy ions (HIs) (carbon, nitrogen and oxygen recoil nuclei) were transported down to a lower energy limit (1 keV for light ions and 5 MeV for HIs). Track energy below the limit was assumed to be locally deposited. For neutron tracks <20 MeV, kerma factors were used to obtain absorbed dose. Results are presented for a discrete set of angles of incidence on an ICRU tissue slab phantom. PMID:19887515

  13. Range measurement of boron isotopes in silicon from 600 keV to 2 MeV

    NASA Astrophysics Data System (ADS)

    Goppelt, P.; Biersack, J. P.; Gebauer, B.; Fink, D.; Bohne, W.; Wilpert, M.; Wilpert, Th.

    1993-06-01

    Ranges of boron isotopes with masses 10 and 11 were measured in silicon for implantation energies of 600 keV, 1.0, 1.5 and 2.0 MeV by use of high-energy elastic recoil detection analysis (HE-ERDA). The measured ranges were compared with TRIM and PRAL calculations. The experimental data show a deviation to larger depth particularly at higher energies. The ratio of the ranges of the isotopes is always lower than theoretically predicted. The experimental results can be interpreted as follows: the electronic stopping, which dominates this energy regime, increases slower than expected. The maximum of the stopping power is shifted towards lower energies and is lower than calculated. In the lower energy range the stopping power must be larger than predicted leading to smaller ranges for energies up to 1 MeV. Our experiment is in good agreement with former range measurements of Behar et al. [Nucl. Instr. and Meth. B34 (1988) 316] who used the very reliable 10B(n, α) 6Li nuclear reaction technique (neutron depth profiling: NDP), and of Svensson et al. [J. Appl. Phys. 68 (1990) 73] using secondary ion mass spectroscopy (SIMS), who both found this behavior, too.

  14. High order magnetic optics for high dynamic range proton radiography at a kinetic energy 800 MeV

    DOE PAGES

    Sjue, Sky K. L.; Morris, Christopher L.; Merrill, Frank Edward; Mariam, Fesseha Gebre; Saunders, Alexander

    2016-01-14

    Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the protonimaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane.more » Furthermore, comparison with a series of static calibrationimages demonstrates the model’s accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets.« less

  15. Activation cross-sections of proton induced reactions on vanadium in the 37-65 MeV energy range

    NASA Astrophysics Data System (ADS)

    Ditrói, F.; Tárkányi, F.; Takács, S.; Hermanne, A.

    2016-08-01

    Experimental excitation functions for proton induced reactions on natural vanadium in the 37-65 MeV energy range were measured with the activation method using a stacked foil irradiation technique. By using high resolution gamma spectrometry cross-section data for the production of 51,48Cr, 48V, 48,47,46,44m,44g,43Sc and 43,42K were determined. Comparisons with the earlier published data are presented and results predicted by different theoretical codes (EMPIRE and TALYS) are included. Thick target yields were calculated from a fit to our experimental excitation curves and compared with the earlier experimental yield data. Depth distribution curves to be used for thin layer activation (TLA) are also presented.

  16. High order magnetic optics for high dynamic range proton radiography at a kinetic energy of 800 MeV.

    PubMed

    Sjue, S K L; Mariam, F G; Merrill, F E; Morris, C L; Saunders, A

    2016-01-01

    Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the proton imaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane. Comparison with a series of static calibration images demonstrates the model's accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets. PMID:26827356

  17. High order magnetic optics for high dynamic range proton radiography at a kinetic energy of 800 MeV

    NASA Astrophysics Data System (ADS)

    Sjue, S. K. L.; Mariam, F. G.; Merrill, F. E.; Morris, C. L.; Saunders, A.

    2016-01-01

    Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the proton imaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane. Comparison with a series of static calibration images demonstrates the model's accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets.

  18. NUCLEAR CROSS-SECTION CALCULATIONS IN THE 1 MEV TO 5 GEV RANGE WITH COMBINED SEMI-CLASSICAL AND QUANTUM MECHANICAL MODELS

    SciTech Connect

    Guimaraes, F.B.

    2002-03-07

    In this work we describe neutron and proton induced reaction cross-sections for iron produced by the codes TNG and CEM95 in the 5 to 300 MeV energy range. TNG calculations cover the 5-90 MeV range, while CEM95 covers the 50-300 MeV high energy range. The two codes show some disagreements in the overlap energy range, both among themselves and with the experimental data, which are presently being addressed. The experimental data used are from NNDC and/or from LA150 NSE references. We also describe some developments for combining TNG and CEM95 into a new code called CETNG (Cascade Exciton TNG).

  19. Extension of the energy range of experimental activation cross-sections data of deuteron induced nuclear reactions on indium up to 50MeV.

    PubMed

    Tárkányi, F; Ditrói, F; Takács, S; Hermanne, A; Ignatyuk, A V

    2015-11-01

    The energy range of our earlier measured activation cross-sections data of longer-lived products of deuteron induced nuclear reactions on indium were extended from 40MeV up to 50MeV. The traditional stacked foil irradiation technique and non-destructive gamma spectrometry were used. No experimental data were found in literature for this higher energy range. Experimental cross-sections for the formation of the radionuclides (113,110)Sn, (116m,115m,114m,113m,111,110g,109)In and (115)Cd are reported in the 37-50MeV energy range, for production of (110)Sn and (110g,109)In these are the first measurements ever. The experimental data were compared with the results of cross section calculations of the ALICE and EMPIRE nuclear model codes and of the TALYS 1.6 nuclear model code as listed in the on-line library TENDL-2014.

  20. Excitation of 11/2- isomeric state in 137Ce in (γ,n) reaction within 10-22MeV energy range

    NASA Astrophysics Data System (ADS)

    Mazur, V. M.; Bigan, Z. M.; Derechkey, P. S.; Symochko, D. M.

    2016-09-01

    Isomeric yields ratios and energy differential cross-section of metastable state excitation in the 138Ce(γ,n)137m,gCe reaction has been studied in the 10-22MeV end-point energy range of bremsstrahlung beams. Experimental data are compared with Hauser-Feshbach calculations performed with TALYS-1.6 statistical model code.

  1. Interaction of Gold Nuclei with Photoemulsion Nuclei at Energies in the Range 100-1200 MeV per Nucleon and Cascade-Evaporation Model

    SciTech Connect

    Bogdanov, S.D.; Shablya, E.Ya.; Kosmach, V.F.; Vokal, S.; Plyuschev, V.A.

    2005-09-01

    The interaction of gold nuclei with photoemulsion nuclei at energies in the range 100-1200 MeV per nucleon was studied experimentally. A consistent comparison of the experimental data obtained in this way with the results of the calculations based on the cascade-evaporation model is performed.

  2. Elastic Scattering of {sup 7}Li+{sup 27}Al at Backward Angles in the 7-11 MeV Energy Range for Application in RBS

    SciTech Connect

    Carnelli, P. F. F.; Arazi, A.; Cardona, M. A.; Figueira, J. M.; Hojman, D.; Martinez Heimann, D.; Negri, A. E.; Pacheco, A. J.; Abriola, D.; Capurro, O. A.; Fimiani, L.; Grinberg, P.; Marti, G. V.; Fernandez Niello, J. O.

    2010-08-04

    We have measured elastic excitation functions for the {sup 7}Li+{sup 27}Al system, in an energy range close to its Coulomb barrier (E{sub lab} = 8.4 MeV) in steps of 0.25 MeV. For this purpose, an array of eight surface-barrier detectors was used. To get an insight on the background composition (mainly {alpha} particles), a telescope-detector was used for atomic-number identification. Identical measurements for the {sup 6}Li+{sup 27}Al system are planned for the near future.

  3. The sup 252 Cf(sf) neutron spectrum in the 5- to 20-MeV energy range

    SciTech Connect

    Marten, H.; Richter, D.; Seeliger, D. ); Fromm, W.D. ); Bottger, R.; Klein, H. )

    1990-11-01

    This paper reports on the {sup 252}Cf neutron spectrum measured at high energies with a miniature ionization chamber and two different NE-213 neutron detectors. The gamma-ray background and the main cosmic background caused by muons were suppressed by applying efficient pulse-shape discrimination. On the basis of two-dimensional spectroscopy of the neutron time-of-flight and scintillation pulse height, the sliding bias method is used to minimize experimental uncertainties. The experimental data, corrected for several systematic influences, confirm earlier results that show negative deviations from a reference Maxwellian distribution with a 1.42-MeV spectrum temperature for neutron energies above 6 MeV. Experimental results of this work are compared with various statistical model approaches to the {sup 252}Cf(sf) neutron spectrum.

  4. Experimental investigation of the 19F( n, α)16N reaction excitation function in the neutron energy range of 4 to 7.35 MeV

    NASA Astrophysics Data System (ADS)

    Bondarenko, I. P.; Khryachkov, V. A.; Ivanova, T. A.; Kuz'minov, B. D.; Semenova, N. N.; Sergachev, A. I.

    2013-07-01

    The interaction of neutrons with light nuclei study is of interest for understanding nuclear-reaction mechanisms. Fluorine nuclei are worth particular attention because they are abundant in the core of the promising molten-salt reactors and can noticeably affect the chain reaction kinetics. In this work we have experimentally investigated the 19F( n, α)16N reaction cross-section at neutron energies ranging from 4 to 7.35 MeV.

  5. Au, Bi, Co and Nb cross-section measured by quasimonoenergetic neutrons from p + 7Li reaction in the energy range of 18-36 MeV

    NASA Astrophysics Data System (ADS)

    Majerle, M.; Bém, P.; Novák, J.; Šimečková, E.; Štefánik, M.

    2016-09-01

    Au, Bi, Co and Nb samples were irradiated several times with quasi-monoenergetic neutrons from p + 7Li reaction in the energy range of 18-36 MeV. The activities of the samples were measured with the HPGe detector and the reaction rates were calculated. The cross-sections were extracted using the SAND-II method with the reference cross-sections from the EAF-2010 database. The uncertainties of the final results are discussed.

  6. A Multigroup Library of Neutron and Gamma Cross Sections and Response Functions in the Energy Range up to 800 MeV.

    1987-05-20

    Version 00 The energy range of the library, from thermal to 800 MeV is relevant to the solution of shielding, nuclear heating, and other radiation protection problems connected with the accelerator neutron sources e.g. spallation target. The data contains 10 elements of shielding and biological importance. They can be easily implemented to the neutron transport codes like ANISN and DOT by using the activity option.

  7. The ( 3He, tf) as a surrogate reaction to determine ( n, f) cross sections in the 10-20 MeV energy range

    NASA Astrophysics Data System (ADS)

    Basunia, M. S.; Clark, R. M.; Goldblum, B. L.; Bernstein, L. A.; Phair, L.; Burke, J. T.; Beausang, C. W.; Bleuel, D. L.; Darakchieva, B.; Dietrich, F. S.; Evtimova, M.; Fallon, P.; Gibelin, J.; Hatarik, R.; Jewett, C. C.; Lesher, S. R.; McMahan, M. A.; Rodriguez-Vieitez, E.; Wiedeking, M.

    2009-06-01

    The surrogate reaction 238U( 3He, tf) is used to determine the 237Np( n, f) cross section indirectly over an equivalent neutron energy range from 10 to 20 MeV. A self-supporting ˜761 μg/cm 2 metallic 238U foil was bombarded with a 42 MeV 3He 2+ beam from the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory (LBNL). Outgoing charged particles and fission fragments were identified using the Silicon Telescope Array for Reaction Studies (STARS) consisted of two 140 μm and one 1000 μm Micron S2 type silicon detectors. The 237Np( n, f) cross sections, determined indirectly, were compared with the 237Np( n, f) cross section data from direct measurements, the Evaluated Nuclear Data File (ENDF/B-VII.0), and the Japanese Evaluated Nuclear Data Library (JENDL 3.3) and found to closely follow those datasets. Use of the ( 3He, tf) reaction as a surrogate to extract ( n, f) cross sections in the 10-20 MeV equivalent neutron energy range is found to be suitable.

  8. Neutron-induced fission cross section of 237Np in the keV to MeV range at the CERN n_TOF facility

    NASA Astrophysics Data System (ADS)

    Diakaki, M.; Karadimos, D.; Vlastou, R.; Kokkoris, M.; Demetriou, P.; Skordis, E.; Tsinganis, A.; Abbondanno, U.; Aerts, G.; Álvarez, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.; Badurek, G.; Baumann, P.; Bečvář, F.; Berthoumieux, E.; Calviani, M.; Calviño, F.; Cano-Ott, D.; Capote, R.; Carrillo de Albornoz, A.; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Couture, A.; Cox, J.; David, S.; Dolfini, R.; Domingo-Pardo, C.; Dorochenko, A.; Dridi, W.; Duran, I.; Eleftheriadis, Ch.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; Fitzpatrick, L.; Frais-Koelbl, H.; Fuji, K.; Furman, W.; Goncalves, I.; Gallino, R.; Gonzalez-Romero, E.; Goverdovski, A.; Gramegna, F.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Igashira, M.; Ioannidis, K.; Isaev, S.; Jericha, E.; Kadi, Y.; Käppeler, F.; Karamanis, D.; Kerveno, M.; Ketlerov, V.; Koehler, P.; Kolokolov, D.; Konovalov, V.; Krtička, M.; Lamboudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marques, L.; Marrone, S.; Massimi, C.; Mastinu, P.; Mengoni, A.; Milazzo, P. M.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; O'Brien, S.; Oshima, M.; Pancin, J.; Papadopoulos, C.; Paradela, C.; Patronis, N.; Pavlik, A.; Pavlopoulos, P.; Perrot, L.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Pretel, C.; Quesada, J.; Rauscher, T.; Reifarth, R.; Rosetti, M.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Sarchiapone, L.; Savvidis, I.; Sedysheva, M.; Stamoulis, K.; Stephan, C.; Tagliente, G.; Tain, J. L.; Tassan-Got, L.; Tavora, L.; Terlizzi, R.; Vannini, G.; Vaz, P.; Ventura, A.; Villamarin, D.; Vincente, M. C.; Vlachoudis, V.; Voss, F.; Wendler, H.; Wiescher, M.; Wisshak, K.; n TOF Collaboration

    2016-03-01

    The neutron-induced fission cross section of 237Np was experimentally determined at the high-resolution and high-intensity facility n_TOF, at CERN, in the energy range 100 keV to 9 MeV, using the 235U(n ,f ) and 238U(n ,f ) cross section standards below and above 2 MeV, respectively. A fast ionization chamber was used in order to detect the fission fragments from the reactions and the targets were characterized as far as their mass and homogeneity are concerned by means of α spectroscopy and Rutherford backscattering spectroscopy respectively. Theoretical calculations within the Hauser-Feshbach formalism have been performed, employing the empire code, and the model parameters were tuned in order to successfully reproduce the experimental fission cross-sectional data and simultaneously all the competing reaction channels.

  9. Neutron-induced fission cross section of Np237 in the keV to MeV range at the CERN n_TOF facility

    DOE PAGES

    Diakaki, M.; Karadimos, D.; Vlastou, R.; Kokkoris, M.; Demetriou, P.; Skordis, E.; Tsinganis, A.; Abbondanno, U.; Aerts, G.; Álvarez, H.; et al

    2016-03-17

    We experimentally determined the neutron-induced fission cross section of Np-237 at the high-resolution and high-intensity facility n_TOF, at CERN, in the energy range 100 keV to 9 MeV, using the U-235(n, f) and U-238(n, f) cross section standards below and above 2 MeV, respectively. Moreover, a fast ionization chamber was used in order to detect the fission fragments from the reactions and the targets were characterized as far as their mass and homogeneity are concerned by means of a spectroscopy and Rutherford backscattering spectroscopy respectively. Finally, theoretical calculations within the Hauser-Feshbach formalism have been performed, employing the EMPIRE code, andmore » the model parameters were tuned in order to successfully reproduce the experimental fission cross-sectional data and simultaneously all the competing reaction channels.« less

  10. Response functions of Fuji imaging plates to monoenergetic protons in the energy range 0.6-3.2 MeV

    SciTech Connect

    Bonnet, T.; Denis-Petit, D.; Gobet, F.; Hannachi, F.; Tarisien, M.; Versteegen, M.; Aleonard, M. M.

    2013-01-15

    We have measured the responses of Fuji MS, SR, and TR imaging plates (IPs) to protons with energies ranging from 0.6 to 3.2 MeV. Monoenergetic protons were produced with the 3.5 MV AIFIRA (Applications Interdisciplinaires de Faisceaux d'Ions en Region Aquitaine) accelerator at the Centre d'Etudes Nucleaires de Bordeaux Gradignan (CENBG). The IPs were irradiated with protons backscattered off a tantalum target. We present the photo-stimulated luminescence response of the IPs together with the fading measurements for these IPs. A method is applied to allow correction of fading effects for variable proton irradiation duration. Using the IP fading corrections, a model of the IP response function to protons was developed. The model enables extrapolation of the IP response to protons up to proton energies of 10 MeV. Our work is finally compared to previous works conducted on Fuji TR IP response to protons.

  11. The (3He,tf) as a surrogate reaction to determine (n,f) cross sections in the 10 to 20 MeV energy range

    SciTech Connect

    Basunia, M. S.; Clark, R. M.; Goldblum, B. L.; Bernstein, L. A.; Phair, L.; Burke, J. T.; Beausang, C. W.; Bleuel, D. L.; Darakchieva, B.; Dietrich, F. S.; Evtimova, M.; Fallon, P.; Gibelin, J.; Hatarik, R.; Jewett, C. C.; Lesher, S. R.; McMahan, M. A.; Rodriguez-Vieitez, E.; Wiedeking, M.

    2009-02-25

    The surrogate reaction 238U(3He,tf) is used to determine the 237Np(n,f) cross section indirectly over an equivalent neutron energy range from 10 to 20 MeV. A self-supporting ~;;761 mu g/cm2 metallic 238U foil was bombarded with a 42 MeV 3He2+ beam from the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory (LBNL). Outgoing charged particles and fission fragments were identified using the Silicon Telescope Array for Reaction Studies (STARS), consists of two 140 mu m and one 1000 mu m Micron S2 type silicon detectors. The 237Np(n,f) cross sections, determined indirectly, were compared with the 237Np(n,f) cross section data from direct measurements, the Evaluated Nuclear Data File (ENDF/B-VII.0), and the Japanese Evaluated Nuclear Data Library (JENDL 3.3) and found to closely follow those datasets. Use of the (3He,tf) reaction as a surrogate to extract (n,f) cross section in the 10 to 20 MeV equivalent neutron energy is found to be suitable.

  12. Response of a BaF 2 scintillation detector to quasi-monoenergetic fast neutrons in the range of 45 to 198 MeV

    NASA Astrophysics Data System (ADS)

    Gunzert-Marx, K.; Schardt, D.; Simon, R. S.; Gutermuth, F.; Radon, T.; Dangendorf, V.; Nolte, R.

    2005-01-01

    We have studied the neutron response of a scintillation detector consisting of a 14 cm long, hexagonal-shaped BaF 2-crystal with an inner diameter of 8.75 cm coupled to an EMI9821QB photomultiplier tube. The detector was exposed to calibrated quasi-monoenergetic neutron fields obtained from 7Li(p,n) 7Be reactions. The measurements were performed at neutron energies of 45, 60, 96, 147 and 198 MeV as given by the energies of the incident protons. The experimental pulse-height spectra of the BaF 2-detector are compared with Monte Carlo simulations using the FLUKA code. The detection efficiency of the BaF 2-detector in the energy range of 45-198 MeV was determined as a function of the discriminator threshold and compared to the literature data. At neutron energies above 100 MeV the detection efficiency of the BaF 2-detector was found to be a factor of two higher than that of an NE213-detector of comparable size.

  13. Secondary neutron spectrum from 250-MeV passively scattered proton therapy: Measurement with an extended-range Bonner sphere system

    SciTech Connect

    Howell, Rebecca M.; Burgett, E. A.

    2014-09-15

    Purpose: Secondary neutrons are an unavoidable consequence of proton therapy. While the neutron dose is low compared to the primary proton dose, its presence and contribution to the patient dose is nonetheless important. The most detailed information on neutrons includes an evaluation of the neutron spectrum. However, the vast majority of the literature that has reported secondary neutron spectra in proton therapy is based on computational methods rather than measurements. This is largely due to the inherent limitations in the majority of neutron detectors, which are either not suitable for spectral measurements or have limited response at energies greater than 20 MeV. Therefore, the primary objective of the present study was to measure a secondary neutron spectrum from a proton therapy beam using a spectrometer that is sensitive to neutron energies over the entire neutron energy spectrum. Methods: The authors measured the secondary neutron spectrum from a 250-MeV passively scattered proton beam in air at a distance of 100 cm laterally from isocenter using an extended-range Bonner sphere (ERBS) measurement system. Ambient dose equivalent H*(10) was calculated using measured fluence and fluence-to-ambient dose equivalent conversion coefficients. Results: The neutron fluence spectrum had a high-energy direct neutron peak, an evaporation peak, a thermal peak, and an intermediate energy continuum between the thermal and evaporation peaks. The H*(10) was dominated by the neutrons in the evaporation peak because of both their high abundance and the large quality conversion coefficients in that energy interval. The H*(10) 100 cm laterally from isocenter was 1.6 mSv per proton Gy (to isocenter). Approximately 35% of the dose equivalent was from neutrons with energies ≥20 MeV. Conclusions: The authors measured a neutron spectrum for external neutrons generated by a 250-MeV proton beam using an ERBS measurement system that was sensitive to neutrons over the entire

  14. Energy dependence of proton induced fission cross sections for heavy nuclei in the energy range 200-1000 MeV

    SciTech Connect

    Kotov, A. A.; Vaishnene, L. A.; Vovchenko, V. G.; Gavrikov, Yu. A.; Poliakov, V. V.; Tverskoy, M. G.; Fedorov, O. Ya.; Chestnov, Yu. A.; Shchetkovskiy, A. I.; Shvedchikov, A. V.; Doroshenko, A. Yu.; Fukahori, T.

    2006-09-15

    Total cross sections for proton induced fission of {sup nat}Pb, {sup 209}Bi, {sup 232}Th, {sup 233}U, {sup 235}U, {sup 238}U, {sup 237}Np, and {sup 239}Pu nuclei were measured in the range 200-1000 MeV with an energy step of 100 MeV. The experiment was carried out at 1 GeV in a PNPI synchrocyclotron. Complementary fragments of the binary fission from a thin target were detected in coincidence by two parallel plate avalanche counters (PPAC) located close to the target. An assembly of the two PPACs and with the target in between them was placed directly into the beam, which provided a large solid angle acceptance. The beam monitoring system employed a scintillation counter telescope that was used for direct proton counting as well as for registration of the elastic pp-scattering events from the auxiliary (CH{sub 2}){sub n} target. The measured energy dependence of the total fission cross sections is presented. The results are compared with other available experimental data as well as with calculations in the frame of the cascade-evaporation model.

  15. Isobar-model partial-wave analysis of πN-->ππN in the c.m. energy range 1320-1930 MeV

    NASA Astrophysics Data System (ADS)

    Manley, D. Mark; Arndt, Richard A.; Goradia, Yogesh; Teplitz, Vigdor L.

    1984-09-01

    We study the reactions πN-->ππN in the center-of-mass energy range 1320-1930 MeV within the framework of the isobar model. The present analysis includes over 30% more events than the most extensive previous analysis. Data for π-p-->π+π-n, π-p-->π0π-p, π+p-->π0π+p, and π+p-->π+π+n are simultaneously fitted assuming production of ɛ, ρ, Δ(P33) and N*(P11). The cross section for π-p-->π0π0n is predicted and found to be in good agreement with experiment. πN-->πN* amplitudes for I=12 are investigated for the first time. We confirm the existence of a significant πN* decay for the second P33 resonance and determine that πN* is the dominant inelastic channel for the P31 partial wave. The ρN decay of the G17 wave is observed for the first time. Evidence is found for unestablished resonances near 1900 MeV in the S11, P11, P13, and F15 partial waves. We also discuss evidence for a second F35 resonance. Signs of resonant amplitudes determined from this analysis are compared with results of previous analyses and with predictions from several models.

  16. Measurement of the neutron fields produced by a 62 MeV proton beam on a PMMA phantom using extended range Bonner sphere spectrometers

    NASA Astrophysics Data System (ADS)

    Amgarou, K.; Bedogni, R.; Domingo, C.; Esposito, A.; Gentile, A.; Carinci, G.; Russo, S.

    2011-10-01

    The experimental characterization of the neutron fields produced as parasitic effect in medical accelerators is assuming an increased importance for either the patient protection or the facility design aspects. Medical accelerators are diverse in terms of particle type (electrons or hadrons) and energy, but the radiation fields around them have in common (provided that a given threshold energy is reached) the presence of neutrons with energy span over several orders of magnitude. Due to the large variability of neutron energy, field or dosimetry measurements in these workplaces are very complex, and in general, cannot be performed with ready-to-use commercial instruments. In spite of its poor energy resolution, the Bonner Sphere Spectrometer (BSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. The energy range of this instrument is limited to E<20 MeV if only polyethylene spheres are used, but can be extended to hundreds of MeV by including metal-loaded spheres (extended range BSS, indicated with ERBSS). With the aim of providing useful data to the scientific community involved in neutron measurements at hadron therapy facilities, an ERBSS experiment was carried out at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) of INFN—LNS (Laboratori Nazionali del Sud), where a proton beam routinely used for ophthalmic cancer treatments is available. The 62 MeV beam was directed towards a PMMA phantom, simulating the patient, and two neutron measurement points were established at 0° and 90° with respect to the beam-line. Here the ERBSS of UAB (Universidad Autónoma de Barcelona— Grup de Física de les Radiacions) and INFN (Istituto Nazionale di Fisica Nucleare—Laboratori Nazionali di Frascati) were exposed to characterize the "forward" and "sideward" proton-induced neutron fields. The use of two ERBSS characterized by different set of spheres, central detectors, and independently established and

  17. Analysis of gamma-ray spectra from foils activated in a range-thick lead target by 800-MeV protons. Final technical report

    SciTech Connect

    Laird, C.E.; Mullins, D.H.

    1995-06-12

    Approximately 400 gamma-ray spectra have been analyzed to obtain the types and quantities of radioisotopes produced when 800-MeV protons interact with a range-thick lead target. These spectra were obtained from the radioactive decay of product isotopes in lead disks placed at various depths and radial positions within the target. These spectra were analyzed with the computer code HYPERMET and the photopeak areas were reduced to nuclei produced per incident proton per cubic centimeter of material. Product nuclei ranged from atomic mass 160 to mass 206 and over a range of half lives from a few minutes to several weeks. The results of this analysis have been outlined in this report and transmitted on computer disk to Los Alamos National Laboratory. The consistency of these analyses have been confirmed by a comparison of photopeak areas obtained at LANL with the computer code GAMANAL with those from HYPERMET for two gamma-ray spectra. Also, the nuclear production per proton per cm{sub 3} obtained from these two spectra analyzed both at LANL and at EKU have been found to agree to within the statistical accuracy of the peak-fitting programs. This analysis of these 400 gamma-ray spectra has determined the nuclear production per incident proton per cm{sub 3} at five regularly-spaced radial positions and depths up to 40 cm into a range-thick lead target.

  18. Excitation function for 63Cu(n,p)63Ni reaction in neutron energy range up to 15 MeV.

    PubMed

    Takamiya, K; Ota, Y; Akamine, M; Shibata, S; Shibata, T; Ito, Y; Imamura, M; Uwamino, Y; Nogawa, N; Baba, M; Iwasaki, S; Matsuyama, S

    2008-10-01

    The excitation function for the (63)Cu(n,p)(63)Ni reaction has been measured by activation method using the 4.5 MV Dynamitron accelerator of the Fast Neutron Laboratory of Tohoku University. Copper plates and hollow spherical copper shells were irradiated by neutrons of various energy up to 14.9 MeV produced by the T(p,n), D(d,n), and T(d,n) reactions. The (63)Ni produced in the irradiated copper target was chemically separated. The beta-rays emitted from the extracted (63)Ni were measured by a liquid scintillation method. The cross sections obtained were compared with the evaluated data files of JENDL-3.3, ENDF/B-VI and FENDL/A-2.0. Consequently, it is found that FENDL/A-2.0 is consistent with our experimental data in the energy range studied in this work. The effect of proton shell appeared in the excitation function obtained is also discussed.

  19. Elastic neutron scattering at 96 MeV from 12C and 208Pb

    NASA Astrophysics Data System (ADS)

    Klug, J.; Blomgren, J.; Ataç, A.; Bergenwall, B.; Hildebrand, A.; Johansson, C.; Mermod, P.; Nilsson, L.; Pomp, S.; Tippawan, U.; Elmgren, K.; Olsson, N.; Jonsson, O.; Prokofiev, A. V.; Renberg, P.-U.; Nadel-Turonski, P.; Dangtip, S.; Phansuke, P.; Österlund, M.; Le Brun, C.; Lecolley, J. F.; Lecolley, F. R.; Louvel, M.; Marie-Noury, N.; Schweitzer, C.; Eudes, Ph.; Haddad, F.; Lebrun, C.; Koning, A. J.; Bauge, E.; Delaroche, J. P.; Girod, M.; Ledoux, X.; Romain, P.; Madland, D. G.; Amos, K.; Deb, P. K.; Karataglidis, S.; Crespo, R.; Moro, A. M.

    2003-03-01

    A facility for detection of scattered neutrons in the energy interval 50 130 MeV, scattered nucleon detection assembly, has recently been installed at the 20 180 MeV neutron beam line of The Svedberg Laboratory, Uppsala. First results on elastic neutron scattering from 12C and 208Pb at 96 MeV incident neutron energy are presented. This experiment represents the highest neutron energy where the ground state has been resolved from the first excited state in neutron scattering. The results are compared with modern optical model predictions.

  20. Shape of spectra and mean energies of prompt fission neutrons from {sup 237}Np fission induced by primary neutrons of energy in the range E{sub n} < 20 MeV

    SciTech Connect

    Svirin, M. I.

    2008-10-15

    An analysis of the spectrum of prompt neutrons originating from {sup 237}Np fission induced by primary neutrons of energy E{sub n} = 14.7 MeV confirms the results obtained previously for {sup 232}Th (E{sub n} = 14.7, 17.7 MeV), {sup 235}U (14.7 MeV), and {sup 238}U (13.2, 14.7, 16, and 17.7 MeV) nuclei. In the experimental spectrum measured in the emissive fission of {sup 237}Np, there is also an excess of soft neutrons in the energy range E < 2 MeV in relation to what follows from a traditional theoretical description that considers two sources of prompt fission neutrons: fully accelerated fission fragments and excited nuclei prior to their separation. In just the same way as in the cases of {sup 232}Th and {sup 235,238}U, the shape of the prompt-fission-neutron spectrum for {sup 237}Np is reproduced theoretically over the entire measured range of secondary-neutron energies upon including nonaccelerated fragments as a third source of neutrons in the computational scheme. A description of the spectra and mean energies of prompt fission neutrons versus the bombarding-neutron energy is obtained on the basis of experimental data and their analysis. The results on mean energies are compared with data on the proton-induced fission of {sup 236,238}U nuclei.

  1. Vacancy-related defects in n-type Si implanted with a rarefied microbeam of accelerated heavy ions in the MeV range

    NASA Astrophysics Data System (ADS)

    Capan, I.; Pastuović, Ž.; Siegele, R.; Jaćimović, R.

    2016-04-01

    Deep level transient spectroscopy (DLTS) has been used to study vacancy-related defects formed in bulk n-type Czochralski-grown silicon after implantation of accelerated heavy ions: 6.5 MeV O, 10.5 MeV Si, 10.5 MeV Ge, and 11 MeV Er in the single ion regime with fluences from 109 cm-2 to 1010 cm-2 and a direct comparison made with defects formed in the same material irradiated with 0.7 MeV fast neutron fluences up to 1012 cm-2. A scanning ion microprobe was used as the ion implantation tool of n-Cz:Si samples prepared as Schottky diodes, while the ion beam induced current (IBIC) technique was utilized for direct ion counting. The single acceptor state of the divacancy V2(-/0) is the most prominent defect state observed in DLTS spectra of n-CZ:Si samples implanted by selected ions and the sample irradiated by neutrons. The complete suppression of the DLTS signal related to the double acceptor state of divacancy, V2(=/-) has been observed in all samples irradiated by ions and neutrons. Moreover, the DLTS peak associated with formation of the vacancy-oxygen complex VO in the neutron irradiated sample was also completely suppressed in DLTS spectra of samples implanted with the raster scanned ion microbeam. The reason for such behaviour is twofold, (i) the local depletion of the carrier concentration in the highly disordered regions, and (ii) the effect of the microprobe-assisted single ion implantation. The activation energy for electron emission for states assigned to the V2(-/0) defect formed in samples implanted by single ions follows the Meyer-Neldel rule. An increase of the activation energy is strongly correlated with increasing ion mass.

  2. Double beta decay of Uranium-238: Proton reactions of {sup 238}U in 5--12 MeV range. Final report, April 15, 1987--March 31, 1992

    SciTech Connect

    Turkevich, A.; Economou, T.E.

    1993-06-01

    This report is in two parts. The first part reports on the experimental work determining the half-life for double beta decay of {sup 238}U to {sup 238}PU to be (2.0 {plus_minus} 0.6) {times} 10{sup 21} years. This is the first evidence for a third mode of decay of this heaviest naturally occurring nucleus. This rate is about 10{sup 6} times slower than spontaneous fission, which itself is about 10{sup 6} times slower than alpha decay. The implication of this double beta decay to neutrino masses depends on uncertain theoretical calculations of the rate for such a heavy nucleus. The second part reports on yields of principal fission products from 5.6, 7.3, 9.4, and 11.5 MeV proton interactions with {sup 238}U. The yields at 11.5 MeV are similar to those from 14 MeV neutron fission of {sup 238}U. At the same time, the production cross sections of {sup 238}Np at the same energies are determined. This nuclide is produced as often as fission at the lowest energy but only 3.8% as often at the highest energy.

  3. Point-by-Point model calculation of the prompt neutron multiplicity distribution ν (A ) for 238U(n ,f ) at incident neutron energies ranging from 1 MeV to 80 MeV

    NASA Astrophysics Data System (ADS)

    Tudora, A.; Hambsch, F.-J.; Tobosaru, V.

    2016-10-01

    Prompt neutron multiplicity distributions ν(A ) are generally required for prompt emission correction of double energy (2 E ) measurements of fission fragments in order to determine pre-neutron fragment properties. The lack of experimental ν(A ) data especially at higher incident neutron energy imposes the use of prompt emission models to predict ν(A ). At incident neutron energies (En ) where multiple fission chances are involved, the Point-by-Point (PbP) model of prompt emission is able to provide the individual ν(A ) of the compound nuclei of the main and secondary nucleus chains that are undergoing fission at a given En . The total ν(A ) are obtained by averaging these individual ν(A ) over the fission chance probabilities (expressed as total and partial fission cross-section ratios). An indirect validation of the total ν(A ) results is proposed. At high En (above 70 MeV) the PbP results of individual ν(A ) of the first few nuclei of the main and secondary nucleus chains exhibit an almost linear increase. This shape is explained by the damping of shell effects entering the superfluid expression of the level-density parameters. They tend to approach the asymptotic values for a great part of the fragments. This fact leads to a smooth and almost linear increase of fragment excitation energy with the fragment mass number that is reflected in a smooth and almost linear behavior of individual ν(A ). The comparison of the present results with those of the GEF code reveals different shapes of ν(A ) as well as different total average neutron multiplicity as a function of the En . At high En the PbP calculations definitely reflect the influence of the almost linear shape of individual ν(A ) of the first few nuclei of the U and Pa chains. The differences between the total ν(A ) obtained by averaging the PbP results of individual ν(A ) over fission cross-section ratios of different evaluations are insignificant.

  4. Neutron spectral and angular distribution measurements for 113 and 256 MeV protons on range-thick Al and sup 238 U targets using the foil activation techniques

    SciTech Connect

    Greenwood, L.R.; Intasorn, A.

    1989-07-01

    Second neutron yields, energy spectra, and angular distributions have been measured at seven angles from 0 to 150{degree} for 113 and 256 MeV protons stopped in range-thick targets of aluminum and depleted uranium ({sup 238}U). Thin foil stacks of ten different materials were activated by secondary neutrons at distances of 20--30 cm from the targets. Following each irradiation, 30--40 different activation products were measured by gamma-ray spectroscopy. These activation rates were then used to adjust neutron energy spectra calculated by the HETC computer code. Activation cross sections were taken from ENDF/BV below 20 MeV, from literature values tested in Be(d,n) fields up to 50 MeV, and from proton spallation data and calculations from 50--250 MeV. Spectral adjustments were made with the STAY'SL computer code using a least-squares technique to minimize {chi}{sup 2} for a covariance matrix determined from uncertainties in the measured activities, cross sections, and calculated flux spectra. Neutron scattering effects were estimated from foil packets irradiated at different distances from the target. Proton effects were measured with (p,n) reactions. Systematic differences were found between the adjusted and calculated neutron spectra, namely, that HETC underpredicts the neutron flux at back angles by a factor of 2--3 and slightly overpredicts the flux at forward angles. 19 refs., 23 figs., 13 tabs.

  5. Effective atomic number and electron density of amino acids within the energy range of 0.122-1.330 MeV

    NASA Astrophysics Data System (ADS)

    More, Chaitali V.; Lokhande, Rajkumar M.; Pawar, Pravina P.

    2016-08-01

    Photon attenuation coefficient calculation methods have been widely used to accurately study the properties of amino acids such as n-acetyl-L-tryptophan, n-acetyl-L-tyrosine, D-tryptophan, n-acetyl-L-glutamic acid, D-phenylalanine, and D-threonine. In this study, mass attenuation coefficients (μm) of these amino acids for 0.122-, 0.356-, 0.511-, 0.662-, 0.884-, 1.170, 1.275-, 1.330-MeV photons are determined using the radio-nuclides Co57, Ba133, Cs137, Na22, Mn54, and Co60. NaI (Tl) scintillation detection system was used to detect gamma rays with a resolution of 8.2% at 0.662 MeV. The calculated attenuation coefficient values were then used to determine total atomic cross sections (σt), molar extinction coefficients (ε), electronic cross sections (σe), effective atomic numbers (Zeff), and effective electron densities (Neff) of the amino acids. Theoretical values were calculated based on the XCOM data. Theoretical and experimental values are found to be in a good agreement (error<5%). The variations of μm, σt, ε, σe, Zeff, and Neff with energy are shown graphically. The values of μm, σt, ε, σe are higher at lower energies, and they decrease sharply as energy increases; by contrast, Zeff and Neff were found to be almost constant.

  6. OBSERVATIONS OF THE 2006 DECEMBER 13 AND 14 SOLAR PARTICLE EVENTS IN THE 80 MeV n{sup -1}-3 GeV n{sup -1} RANGE FROM SPACE WITH THE PAMELA DETECTOR

    SciTech Connect

    Adriani, O.; Bonechi, L.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; Bruno, A.; Boezio, M.; Bonvicini, V.; Bogomolov, E. A.; Bongi, M.; Bottai, S.; Borisov, S.; Casolino, M.; De Pascale, M. P.; Cafagna, F.; Campana, D.; Carbone, R.; Consiglio, L.; Carlson, P.; Castellini, G.; and others

    2011-12-01

    We present the space spectrometer PAMELA observations of proton and helium fluxes during the 2006 December 13 and 14 solar particle events. This is the first direct measurement of the solar energetic particles in space with a single instrument in the energy range from {approx}80 MeV n{sup -1} up to {approx}3 GeV n{sup -1}. For the December 13 event, measured energy spectra of solar protons and helium are compared with results obtained by neutron monitors and other detectors. Our measurements show a spectral behavior different from those derived from the neutron monitor network. No satisfactory analytical fitting was found for the energy spectra. During the first hours of the December 13 event, solar energetic particles spectra were close to the exponential form, demonstrating rather significant temporal evolution. Solar He with energy up to 1 GeV n{sup -1} was recorded on December 13. For the December 14 event, energy of solar protons reached 600 MeV, whereas the maximum energy of He was below 100 MeV n{sup -1}. The spectra were slightly bent in the lower energy range and preserved their form during the second event. Differences in the particle flux appearance and temporal evolution of these two events may argue for special conditions leading to the acceleration of solar particles up to relativistic energies.

  7. Extension of the energy range of the experimental activation cross-sections data of longer-lived products of proton induced nuclear reactions on dysprosium up to 65MeV.

    PubMed

    Tárkányi, F; Ditrói, F; Takács, S; Hermanne, A; Ignatyuk, A V

    2015-04-01

    Activation cross-sections data of longer-lived products of proton induced nuclear reactions on dysprosium were extended up to 65MeV by using stacked foil irradiation and gamma spectrometry experimental methods. Experimental cross-sections data for the formation of the radionuclides (159)Dy, (157)Dy, (155)Dy, (161)Tb, (160)Tb, (156)Tb, (155)Tb, (154m2)Tb, (154m1)Tb, (154g)Tb, (153)Tb, (152)Tb and (151)Tb are reported in the 36-65MeV energy range, and compared with an old dataset from 1964. The experimental data were also compared with the results of cross section calculations of the ALICE and EMPIRE nuclear model codes and of the TALYS nuclear reaction model code as listed in the latest on-line libraries TENDL 2013.

  8. Microscopic model analysis of the 6He, 6Li+28Si total reaction cross sections at the energy range 5-50 A MeV

    SciTech Connect

    Lukyanov, K. V.; Kukhtina, I. N.; Lukyanov, V. K.; Penionzhkevich, Yu. E.; Sobolev, Yu. G.; Zemlyanaya, E. V.

    2007-05-22

    The existing and some preliminary experimental data on the total cross sections of the 4,6He, 6,7Li+28Si reactions at energies E=5-50 A MeV are demonstrated. The data on 6Li,6He+28Si are analyzed in the framework of the microscopic optical potential with real and imaginary parts obtained with a help of the double-folding procedure and by using the current models of densities of the projectile nuclei. Besides, the microscopic double-folding Coulomb potential is calculated and its effect on cross sections is compared with that when one applies the traditional Coulomb potential of the uniform charge distribution. The semi-microscopic potentials are constructed from both the renormalized microscopic potentials and their derivatives to take into account collective motion effect and to improve an agreement with experimental data.

  9. Studies on effective atomic numbers for photon energy absorption and electron density of some narcotic drugs in the energy range 1 keV-20 MeV

    NASA Astrophysics Data System (ADS)

    Gounhalli, Shivraj G.; Shantappa, Anil; Hanagodimath, S. M.

    2013-04-01

    Effective atomic numbers for photon energy absorption ZPEA,eff, photon interaction ZPI,eff and for electron density Nel, have been calculated by a direct method in the photon-energy region from 1 keV to 20 MeV for narcotic drugs, such as Heroin (H), Cocaine (CO), Caffeine (CA), Tetrahydrocannabinol (THC), Cannabinol (CBD), Tetrahydrocannabivarin (THCV). The ZPEA,eff, ZPI,eff and Nel values have been found to change with energy and composition of the narcotic drugs. The energy dependence ZPEA,eff, ZPI,eff and Nel is shown graphically. The maximum difference between the values of ZPEA,eff, and ZPI,eff occurs at 30 keV and the significant difference of 2 to 33% for the energy region 5-100 keV for all drugs. The reason for these differences is discussed.

  10. Measurement of Recoil Losses and Ranges for Spallation Products Produced in Proton Interactions with Al, Si, Mg at 200 and 500 MeV

    NASA Technical Reports Server (NTRS)

    Sisterson, J. M.

    2005-01-01

    Cosmic rays interact with extraterrestrial materials to produce a variety of spallation products. If these cosmogenic nuclides are produced within an inclusion in such material, then an important consideration is the loss of the product nuclei, which recoil out of the inclusion. Of course, at the same time, some atoms of the product nuclei under study may be knocked into the inclusion from the surrounding material, which is likely to have a different composition to that of the inclusion [1]. For example, Ne-21 would be produced in presolar grains, such as SiC, when irradiated in interstellar space. However, to calculate a presolar age, one needs to know how much 21Ne is retained in the grain. For small grains, the recoil losses might be large [2, 3] To study this effect under laboratory conditions, recoil measurements were made using protons with energies from 66 - 1600 MeV on Si, Al and Ba targets [3, 4, 5].

  11. Elastic Neutron Scattering at 96 MeV

    NASA Astrophysics Data System (ADS)

    Hildebrand, A.; Blomgren, J.; Ataç, A.; Bergenwall, B.; Johansson, C.; Klug, J.; Mermod, P.; Nilsson, L.; Pomp, S.; Österlund, M.; Dangtip, s.; Tippawan, U.; Phansuke, P.; Jonsson, O.; Renberg, P.-U.; Prokofiev, A.; Nadel-Turonski, P.; Elmgren, K.; Olsson, N.; Blideanu, V.; Le Brun, C.; Lecolley, J.-F.; Lecolley, F.-R.; Louvel, M.; Marie-Noury, N.; Schweitzer, C.; Eudes, Ph.; Haddad, F.; Lebrun, C.; Koning, A. J.

    2005-05-01

    A facility for detection of scattered neutrons in the energy interval 50-130 MeV, SCANDAL (SCAttered Nucleon Detection AssembLy), has recently been installed at the 20 - 180-MeV neutron beam line of The Svedberg Laboratory, Uppsala. Elastic neutron scattering from 12C, 16O, 56Fe, 89Y, and 208Pb has been studied at 96 MeV in the 10 - 70° interval. The results from 12C and 208Pb have recently been published,6 while the data from 16O, 56Fe, and 89Y are under analysis. The achieved energy resolution, 3.7 MeV, is about an order of magnitude better than for any previous experiment above 65 MeV incident energy. The present experiment represents the highest neutron energy where the ground state has been resolved from the first excited state in neutron scattering. A novel method for normalization of the absolute scale of the cross section has been used. The estimated normalization uncertainty, 3%, is unprecedented for a neutron-induced differential cross section measurement on a nuclear target. The results are compared with modern optical model predictions, based on phenomenology or microscopic theory. Applications for these measurements are nuclear-waste incineration, single-event upsets in electronics, and fast-neutron therapy.

  12. Threshold photoelectron source for the study of low-energy electron scattering: Total cross section for electron scattering from krypton in the energy range from 14 meV to 20 eV

    SciTech Connect

    Kurokawa, M.; Kitajima, M.; Toyoshima, K.; Odagiri, T.; Kato, H.; Kawahara, H.; Hoshino, M.; Tanaka, H.; Ito, K.

    2010-12-15

    An experimental technique for the measurement of the total cross section for electron scattering from atoms and molecules at high resolution is described. The total cross sections for electron scattering from Kr in the energy range from 14 meV to 20 eV obtained with the technique are also reported. The present technique employs a combination of the penetrating field technique and the threshold photoionization of rare-gas atoms using synchrotron radiation as an electron source in order to produce a high-resolution electron beam at very low energy. The characteristics of the electron sources were determined by measuring the ionizing photon energy dependence of photoelectron yield. Absolute total cross sections for electron scattering are obtained by the attenuation method. The measured absolute values of the total cross sections for electron scattering from Kr agree with those obtained by other groups down to 175 meV, above which several experimental works have been reported. Below 175 meV, the present results generally agree with theoretical cross sections down to 14 meV. The resonant structures in the total cross sections due to Kr{sup -} (4p{sup 5}5s{sup 2} {sup 2}P{sub 3/2}) and the Kr{sup -} (4p{sup 5}5s{sup 2} {sup 2}P{sub 1/2}) Feshbach resonances are also reported. The resolution of the present setup has been estimated from a fit of the measured profile of the Kr{sup -} (4p{sup 5}5s{sup 2} {sup 2}P{sub 3/2}) resonance by the theoretical curve obtained from the resonant scattering theory.

  13. Angular distributions and anisotropy of the fission fragments from neutron-induced fission of 233U and 209Bi in intermediate energy range 1-200 MeV

    NASA Astrophysics Data System (ADS)

    Vorobyev, A. S.; Gagarski, A. M.; Shcherbakov, O. A.; Vaishnene, L. A.; Barabanov, A. L.

    2016-09-01

    New results of the neutron-induced fission experiments carried out at the neutron time-of-flight spectrometer GNEIS of the PNPI are given. Angular distributions of fission fragments from the neutron-induced fission of 233U and 209Bi nuclei have been measured in the energy range 1-200 MeV using position sensitive multiwire proportional counters as fission fragment detector. The recent improvements of the measurement and data processing procedures are described. The data on anisotropy of fission fragments deduced from the measured angular distributions are presented in comparison with the experimental data of other authors.

  14. K -shell ionization cross sections of Al, Si, S, Ca, and Zn for oxygen ions in the energy range 1. 1--8 MeV

    SciTech Connect

    Geretschlaeger, M. ); Smit, Z. ); Steinbauer, E. )

    1992-03-01

    {ital K}-shell ionization cross sections induced by 1.1--8-MeV oxygen ions in Al, Si, S, Ca, and Zn were measured using different target thicknesses. The cross sections for vanishingly thin and for charge-equilibrium targets were obtained by extrapolation. The experimental results are compared to the perturbed stationary-state approximation with energy-loss, Coulomb, and relativistic corrections (ECPSSR) cross sections (Brandt and Lapicki, Phys. Rev. A 23, 1717 (1981)), to the modification of the ECPSSR theory (MECPSSR) (Benka, Geretschlaeger, and Paul, J. Phys. (Paris) Colloq. Suppl. 12, C9-251 (1987)), to the theory for direct Coulomb ionization of the 1{ital s}{sigma} molecular orbital (Montenegro and Sigaud, J. Phys. B 18, 299 (1985)), and to several semiclassical approximation codes using either the united atom binding procedure or the variational approach of Andersen {ital et} {ital al}. (Nucl. Instrum. Methods 192, 79 (1982)). The cross sections were also compared to the statistical molecular-orbital theory of inner-shell ionization for (nearly) symmetric atomic collisions (Mittelman and Wilets, Phys. Rev. 154, 12 (1967)). For fast collisions ({xi}{similar to}1), the ionization cross sections are well reproduced by theories for direct Coulomb ionization. For slower collisions ({xi}{lt}1), the experimental cross sections are systematically higher than the direct-ionization values, but they agree satisfactorily with the summed cross sections for direct Coulomb ionization and for molecular-orbital ionization. Best agreement (within a factor of 2) was found for the sums of MECPSSR and statistical cross sections.

  15. K-italic-shell ionization cross sections for Al, Ti, V, Cr, Fe, Ni, Cu, and Ag by protons and oxygen ions in the energy range 0. 3--6. 4 MeV

    SciTech Connect

    Geretschlaeger, M.; Benka, O.

    1986-08-01

    Absolute K-italic-shell ionization cross sections have been measured for thin targets of Al, Ti, and Cu for protons in the energy range 0.3--2.0 MeV and for thin targets of Ti, V, Cr, Fe, Ni, Cu, and Ag for oxygen ions in the energy range 1.36--6.4 Mev. The experimental results are compared to the perturbed-stationary-state (PSS) approximation with energy-loss (E), Coulomb (C), and relativistic (R) corrections, i.e., the ECPSSR approximation (Brandt and Lapicki), to the semiclassical approximation (Laegsgaard, Andersen, and Lund), and to a theory for direct Coulomb ionization of the 1s-italicsigma molecular orbital (Montenegro and Sigaud (MS)). The proton results agree within 3% with empirical reference cross sections. Also, the ECPSSR provides best overall agreement for protons. For oxygen ions, ECPSSR and MS predict experimental results satisfactorily for scaled velocities xi> or =0.4. For lower scaled velocities, the experimental cross sections become considerably higher than theoretical predictions for Coulomb ionization. This deviation increases with increasing Z-italic/sub 1//Z/sub 2/; it cannot be explained by electron transfer to the projectile or by ionization due to target recoil atoms.

  16. Charge-collection efficiency of single-crystal CVD diamond detector for low-energy charged particles with energies ranging from 100 keV to 2 MeV

    NASA Astrophysics Data System (ADS)

    Sato, Yuki; Murakami, Hiroyuki; Shimaoka, Takehiro; Tsubota, Masakatsu; Kaneko, Junichi H.

    2016-10-01

    The performance of a diamond detector created from a single-crystal diamond grown by chemical vapor deposition was studied for application in detecting charged particles having energies ranging from 100 keV to 2 MeV. Energy peaks of different low-energy ions were clearly observed. However, we observed that the pulse height for individual incident ions decreases with increasing atomic number of the ions. We estimated the charge collection efficiency of the generated charge carriers by the incident charged particles. The charge collection efficiencies are 97.0 ± 0.7% for 2 MeV helium-ions (He+). On the other hand, compared with that of He+, silicon-ions (Si+) and gold-ions (Au3+) show low charge collection efficiency: 70.6 ± 2.2% and 29.5 ± 4.2% for 2 MeV-Si+ and 2 MeV-Au3+, respectively. We also found that the charge collection efficiency decreases as the generated charge density inside the diamond crystal increases.

  17. Energy loss, range, and bremsstrahlung yield for 10-keV to 100-MeV electrons in various elements and chemical compounds

    NASA Astrophysics Data System (ADS)

    Pages, Lucien; Bertel, Evelyne; Joffre, Henri; Sklavenitis, Laodamas

    2012-12-01

    Even though the United States lacks a national climate policy, significant action has occurred at the local and regional levels. Some of the most aggressive climate change policies have occurred at the state and local levels and in interagency cooperation on specific management issues. While there is a long history of partnerships in dealing with a wide variety of policy issues, the uncertainty and the political debate surrounding climate change has generated new challenges to establishing effective policy networks. This paper investigates the formation of climate policy networks in the State of Nevada. It presents a methodology based on social network analysis for assessing the structure and function of local policy networks across a range of substantive climate impacted resources (water, landscape management, conservation, forestry and others). It draws from an emerging literature on federalism and climate policy, public sector innovation, and institutional analysis in socio-ecological systems. Comparisons across different policy issue networks in the state are used to highlight the influence of network structure, connectivity, bridging across vertical and horizontal organizational units, organizational diversity, and flows between organizational nodes.

  18. Determination of integral cross sections of 3H in Al foils monitors irradiated by protons with energies ranging from 40 to 2600 MeV

    NASA Astrophysics Data System (ADS)

    Titarenko, Yu. E.; Batyaev, V. F.; Chauzova, M. V.; Chauzova, M. V.; Kashirin, I. A.; Malinovskiy, S. V.; Pavlov, K. V.; Rogov, V. I.; Titarenko, A. Yu.; Zhivun, V. M.; Mashnik, S. G.; Stankovskiy, A. Yu.

    2016-05-01

    The results of 3H production in Al foil monitors (˜ 59 mg/cm2 thickness) are presented. These foils have been irradiated in 15×15 mm polyethylene bags of ˜ 14 mg/cm2 thickness together with foils of Cr (˜ 395 mg/cm2 thickness) and 56Fe (˜ 332 mg/cm2 thickness) by protons of different energies in a range of 0.04 - 2.6 GeV. The diameters of all the foils were 10.5 mm. The irradiations were carried out at the ITEP accelerator U-10 under the ISTC Project # 3266 in 2006-2009. 3H has been extracted from Al foils using an A307 Sample Oxidizer. An ultra low level liquid scintillation spectrometer Quantulus1220 was used to measure the 3H β-spectra and the SpectraDec software package was applied for spectra processing, deconvolution and 3H activity determination. The values of the Al (p, x)3H reaction cross sections obtained in these experiments are compared with data measured at other labs and with results of simulations by the MCNP6 radiation transport code using the CEM03.03 event generator.

  19. Study of the process e+e- → KS0 KL0 in the center-of-mass energy range 1004-1060 MeV with the CMD-3 detector at the VEPP-2000 e+e- collider

    NASA Astrophysics Data System (ADS)

    Kozyrev, E. A.; Solodov, E. P.; Amirkhanov, A. N.; Anisenkov, A. V.; Aulchenko, V. M.; Banzarov, V. S.; Bashtovoy, N. S.; Berkaev, D. E.; Bondar, A. E.; Bragin, A. V.; Eidelman, S. I.; Epifanov, D. A.; Epshteyn, L. B.; Erofeev, A. L.; Fedotovich, G. V.; Gayazov, S. E.; Grebenuk, A. A.; Gribanov, S. S.; Grigoriev, D. N.; Ignatov, F. V.; Ivanov, V. L.; Karpov, S. V.; Kasaev, A. S.; Kazanin, V. F.; Kirpotin, A. N.; Korobov, A. A.; Kovalenko, O. A.; Kozyrev, A. N.; Koop, I. A.; Krokovny, P. P.; Kuzmenko, A. E.; Kuzmin, A. S.; Logashenko, I. B.; Lukin, P. A.; Mikhailov, K. Yu.; Okhapkin, V. S.; Otboev, A. V.; Pestov, Yu. N.; Popov, A. S.; Razuvaev, G. P.; Ruban, A. A.; Ryskulov, N. M.; Ryzhenenkov, A. E.; Senchenko, A. I.; Shebalin, V. E.; Shemyakin, D. N.; Shwartz, B. A.; Shwartz, D. B.; Sibidanov, A. L.; Shatunov, P. Yu.; Shatunov, Yu. M.; Titov, V. M.; Talyshev, A. A.; Vorobiov, A. I.; Yudin, Yu. V.

    2016-09-01

    The e+e- → KS0 KL0 cross section has been measured in the center-of-mass energy range 1004-1060 MeV at 25 energy points using 6.1 ×105 events with KS0 →π+π- decay. The analysis is based on 5.9 pb-1 of an integrated luminosity collected with the CMD-3 detector at the VEPP-2000 e+e- collider. To obtain ϕ (1020) meson parameters the measured cross section is approximated according to the Vector Meson Dominance model as a sum of the ρ , ω , ϕ-like amplitudes and their excitations. This is the most precise measurement of the e+e- → KS0 KL0 cross section with a 1.8% systematic uncertainty.

  20. Measurement of the total cross section of heavy water in the 0.1 meV-1 eV energy range at 20 and 50 ° C

    NASA Astrophysics Data System (ADS)

    Márquez Damián, J. I.; Granada, J. R.; Baxter, D. V.; Parnell, S. R.; Evans, D. C.

    2016-11-01

    Despite the importance of heavy water as a neutron moderator, there are few measurements of its total neutron cross section for cold and thermal energies, and none of them covers the range of temperature (40-70 ° C) used in moderator and reflector tanks in research reactors, and in CANDU nuclear power plants. To cover this deficit, we measured the total cross section of liquid heavy water at 20 ° C and 50 ° C using the SANS beamline at the LENS facility at Indiana University. The time-of-flight technique was used, in a sample-in/sample-out measurement. The use of the solid methane cold neutron source at LENS allowed measuring in a broad range in energy, from 0.1meV to 1eV. In this paper we present details of the measurement and processing of the data, and comparison with previous experimental measurements and calculation models. This work is included in the Action Plan of the IAEA Coordinated Research Project "Advanced Moderators for Intense Cold Neutron Beams in Materials Research".

  1. Cosmic-ray isotopic composition of C, N, O, Ne, Mg, Si nuclei in the energy range 50-200 MeV per nucleon measured by the Voyager spacecraft during the solar minimum period

    NASA Technical Reports Server (NTRS)

    Lukasiak, A.; Ferrando, P.; Mcdonald, F. B.; Webber, W. R.

    1994-01-01

    The isotopic composition of C, N, O, Ne, Mg, Si cosmic ray nuclei has been measured in the energy range 50-200 MeV per nucleon using data collected by the High-Energy Telescope of the cosmic-ray subsystem experiment on the Voyager 1 and 2 spacecraft. These data were collected during the period of minimum solar activity in 1986-1988 at an average distance of 27 AU with an effective solar modulation that was much less than at the Earth. The isotope analysis, based on the energy loss - total energy method, has a mass resolution of 0.2 amu for carbon and 0.4 amu at silicon. We find a (C-13)/(C-12) ratio slightly lower and a (O-18)/(O-16) ratio slightly enhanced over their solar system value. We also observe the previously reported enhancement of the (Ne-22)/(Ne-20) ratio relative to solar at the cosmic-ray source but only a weak, if any, enhancement of the (Mg-25)/(Mg-24), (Mg-26)/(Mg 24), and (Si-30)/(Si-28) ratios.

  2. Time features of delayed neutrons and partial emissive-fission cross sections for the neutron-induced fission of {sup 232}Th nuclei in the energy range 3.2-17.9 MeV

    SciTech Connect

    Roshchenko, V. A. Piksaikin, V. M. Korolev, G. G.; Egorov, A. S.

    2010-06-15

    The energy dependence of the relative abundances of delayed neutrons and the energy dependence of the half-lives of their precursors in the neutron-induced fission of {sup 232}Th nuclei in the energy range 3.2-17.9 MeV were measured for the first time. A systematics of the time features of delayed neutrons is developed. This systematics makes it possible to estimate the half-life of delayed-neutron precursors as a function of the nucleonic composition of fissile nuclei by using a single parameter set for all nuclides. The energy dependence of the partial cross sections for emissive fission in the reaction {sup 232}Th(n, f) was analyzed on the basis of data obtained for the relative abundances of delayed neutrons and the aforementioned half-lives and on the basis of the created systematics of the time features of delayed neutrons. It was shown experimentally for the first time that the decrease in the cross section after the reaction threshold in the fission of {sup 232}Th nuclei (it has a pronounced first-chance plateau) is not an exclusion among the already studied uranium, plutonium, and curium isotopes and complies with theoretical predictions obtained for the respective nuclei with allowance for shell, superfluid, and collective effects in the nuclear-level density and with allowance for preequilibrium neutron emission

  3. Measurements of the cross section for the (182)W(n,p)(182(m+g))Ta and (184)(n,p)(184)Ta reactions in the 14MeV energy range using the activation technique.

    PubMed

    Song, Yueli; Zhou, Fengqun; Tian, Mingli; Li, Yong; Yuan, Shuqing; Lan, Changlin

    2015-04-01

    The cross section for the (182)W(n,p)(182(m+g))Ta and (184)W(n,p)(184)Ta reactions has been measured in the neutron energy range of 13.5-14.7MeV using the activation technique and a coaxial HPGe γ-ray detector. In our experiment, the fast neutrons were produced by the T(d,n)(4)He reaction at the ZF-300-II Intense Neutron Generator at Lanzhou University. Natural wolfram foils of 99.9% purity were used as target materials. The neutron flux was determined using the monitor reaction (93)Nb(n,2n)(92m)Nb and the neutron energies were determined using the method of cross-section ratio measurements employing the (90)Zr(n,2n)(89)Zr to (93)Nb(n,2n)(92m)Nb reactions. The results of this work are compared with experimental data found in the literature and the estimates obtained from a published empirical formula based on the statistical model with Q-value dependence and odd-even effects taken into consideration.

  4. Elastic neutron scattering at 96 MeV from 12 C and 208 Pb

    NASA Astrophysics Data System (ADS)

    Klug, J.; Blomgren, J.; Ataç, A.; Bergenwall, B.; Hildebrand, A.; Johansson, C.; Mermod, P.; Nilsson, L.; Pomp, S.; Tippawan, U.; Elmgren, K.; Olsson, N.; Jonsson, O.; Prokofiev, A. V.; Renberg, P.-U.; Nadel-Turonski, P.; Dangtip, S.; Phansuke, P.; Österlund, M.; Le Brun, C.; Lecolley, J. F.; Lecolley, F. R.; Louvel, M.; Marie-Noury, N.; Schweitzer, C.; Eudes, Ph.; Haddad, F.; Lebrun, C.; Koning, A. J.; Ledoux, X.

    2003-12-01

    A facility for detection of scattered neutrons in the energy interval 50 130 MeV , SCANDAL, has recently been installed at the 20 180 MeV neutron beam line of the The Svedberg Laboratory, Uppsala. Elastic neutron scattering from 12 C and 208 Pb has been studied at 96 MeV in the 10° 70° interval. The achieved energy resolution, 3.7 MeV , is about an order of magnitude better than for any previous experiment above 65 MeV incident energy. The present experiment represents the highest neutron energy where the ground state has been resolved from the first excited state in neutron scattering. A novel method for normalization of the absolute scale of the cross section has been used. The estimated normalization uncertainty, 3% , is unprecedented for a neutron-induced differential cross section measurement on a nuclear target. The results are compared with modern optical model predictions based on phenomenology or microscopic nuclear theory.

  5. A comprehensive study on energy absorption and exposure buildup factors for some essential amino acids, fatty acids and carbohydrates in the energy range 0.015-15 MeV up to 40 mean free path

    NASA Astrophysics Data System (ADS)

    Kurudirek, Murat; Özdemir, Yüksel

    2011-01-01

    The gamma ray energy absorption ( EABF) and exposure buildup factors ( EBF) have been calculated for some essential amino acids, fatty acids and carbohydrates in the energy region 0.015-15 MeV up to a penetration depth of 40 mfp (mean free path). The five parameter geometric progression (G-P) fitting approximation has been used to calculate both EABF and EBF. Variations of EABF and EBF with incident photon energy, penetration depth and weight fraction of elements have been studied. While the significant variations in EABF and EBF for amino acids and fatty acids have been observed at the intermediate energy region where Compton scattering is the main photon interaction process, the values of EABF and EBF appear to be almost the same for all carbohydrates in the continuous energy region. It has been observed that the fatty acids have the largest EABF and EBF at 0.08 and 0.1 MeV, respectively, whereas the maximum values of EABF and EBF have been observed for aminoacids and carbohydrates at 0.1 MeV. At the fixed energy of 1.5 MeV, the variation of EABF with penetration depth appears to be independent of the variations in chemical composition of the amino acids, fatty acids and carbohydrates. Significant variations were also observed between EABF and EBF which may be due to the variations in chemical composition of the given materials.

  6. K -shell ionization cross sections for Si, P, K, Ca, Zn, and Ga by protons and carbon ions in the energy range 1--6. 4 MeV

    SciTech Connect

    Geretschlaeger, M. ); Smit, Z. ); Benka, O. )

    1990-01-01

    Absolute {ital K}-shell ionization cross sections have been measured for thin targets of Si, P, S, K, Ca, Zn, and Ga using carbon ions between 1.0 and 6.4 MeV and protons of 1 and 2 MeV. The dependence of x-ray production cross sections on target thickness was determined. The experimental results are compared to the semiclassical approximation (Laegsgaard, Andersen, and Lund in 3 Proceedings of the Tenth International Conference on the Physics of Electron and Atomic Collisions, Paris, 1977, edited by G. Watel (North-Holland, Amsterdam 1977)), to the theory for direct Coulomb ionization of the 1{ital s}{sigma} molecular orbital (Montenegro and Sigaud, J. Phys. B. 18, 299 (1985)), to the perturbed stationary-state approximation with energy-loss, Coulomb, and relativistic corrections (ECPSSR) (Brandt and Lapicki, Phys. Rev. A 23, 1717 (1981)), and to the modification of the ECPSSR approximation (MECPSSR) (Benka, Geretschlaeger, and Paul, J. Phys. (Paris) Suppl. 12, C9-251 (1987)). The results for carbon ions are also compared to the statistical molecular orbital theory of inner-shell ionization for symmetric or nearly symmetric atomic collisions (Mittelman and Wilets, Phys. Rev. 154, 12 (1967)).

  7. Cross sections for (n, 2n), (n, p) and (n, ) reactions on osmium isotopes in the neutron energy range of 13.5-14.8 MeV.

    PubMed

    Zhao, Liangyong; Yuan, Jilong; Tuo, Fei; Zhang, Yanbin; Kong, Xiangzhong; Liu, Rong; Jiang, Li

    2008-10-01

    Cross sections for (n, 2n), (n, p) and (n, alpha) reactions on the osmium isotopes were measured in the neutron energies 13.5-14.8 MeV by the activation technique with the monitor reaction (93)Nb(n, 2n)(92 m)Nb. Our measurements were carried out by gamma-detection using a coaxial high-purity germanium (HPGe) detector. Natural high-purity osmium powder (99.9%) was fabricated as the samples. The neutron energies were determined by the cross-section ratios for (93)Nb(n, 2n)(92 m)Nb and (90)Zr(n, 2n)(89 m+g)Zr reactions. The fast neutrons were produced by the T(d, n)(4)He reaction. The results obtained were compared with previous data.

  8. Characterization of 2 MeV, 4 MeV, 6 MeV and 18 MeV buildup caps for use with a 0.6 cubic centimeter thimble ionization chamber

    SciTech Connect

    Salyer, R.L.; VanDenburg, J.W.; Prinja, A.K.; Kirby, T.; Busch, R.; Hong-Nian Jow

    1996-07-01

    The purpose of this research is to characterize existing 2 MeV, 4 MeV and 6 MeV buildup caps, and to determine if a buildup cap can be made for the 0.6 cm{sup 3} thimble ionization chamber that will accurately measure exposures in a high-energy photon radiation field. Two different radiation transport codes were used to computationally characterize existing 2 MeV, 4 MeV, and 6 MeV buildup caps for a 0.6 cm{sup 3} active volume thimble ionization chamber: ITS, The Integrated TIGER Series of Coupled Electron-Photon Monte Carlo Transport Codes; and CEPXS/ONEDANT, A One-Dimensional Coupled Electron-Photon Discrete Ordinates Code Package. These codes were also used to determine the design characteristics of a buildup cap for use in the 18 MeV photon beam produced by the 14 TW pulsed power HERMES-III electron accelerator. The maximum range of the secondary electron, the depth at which maximum dose occurs, and the point where dose and collision kerma are equal have been determined to establish the validity of electronic equilibrium. The ionization chamber with the appropriate buildup cap was then subjected to a 4 MeV and a 6 MeV bremmstrahlung radiation spectrum to determine the detector response.

  9. H{sup +} ion-implantation energy dependence of electronic transport properties in the MeV range in n-type silicon wafers using frequency-domain photocarrier radiometry

    SciTech Connect

    Wang Chinhua; Mandelis, Andreas; Tolev, Jordan; Burchard, Bernd; Meijer, Jan

    2007-06-15

    Industrial n-type Si wafers (resistivity of 5-10 {omega} cm) were H{sup +} ion implanted with energies between 0.75 and 2.00 MeV, and the electronic transport properties of the implanted layer (recombination lifetime, carrier diffusion coefficient, and front-surface and implanted-interface recombination velocities s{sub 1} and s{sub 2}) were studied using photocarrier radiometry (PCR). A quantitative fitting procedure to the diffusing photoexcited free-carrier density wave was introduced using a relatively simple two-layer PCR model in lieu of the more realistic but substantially more complicated three-layer model. The experimental trends in the transport properties of H{sup +}-implanted Si layers extracted from the PCR amplitude and phase data as functions of implantation energy corroborate a physical model of the implanted layer in which (a) overlayer damage due to the light H{sup +} ions decreases with increased depth of implantation at higher energies (b) the implanted region damage close to the interface is largely decoupled from the overlayer crystallinity, and (c) the concentration of implanted H{sup +} ions decreases at higher implantation energies at the interface, thus decreasing the degree of implantation damage at the interface proper.

  10. Determination of 9Be(p,p0)9Be, 9Be(p,d0)8Be and 9Be(p,α0)6Li cross sections at 150° in the energy range 0.5-2.35 MeV

    NASA Astrophysics Data System (ADS)

    Catarino, N.; Barradas, N. P.; Alves, E.

    2016-03-01

    Beryllium and Tungsten have been chosen as the new "plasma facing materials" for fusion reactors. Understanding plasma wall interactions and their effects such as erosion and redeposition leading to the formation of alloys from the different materials present in the reactor chamber, is critical to model the retention of hydrogen isotopes by the wall materials. Determining the amount and the depth profile of Be and other elements deposited in the walls is a mandatory requirement in fusion reactors, making the knowledge of the relevant cross sections essential for IBA analysis. In this work we measured the 9Be(p,p0)9Be, 9Be(p,d0)8Be and 9Be(p,α0)6Li cross sections in the energy range 0.5-2.35 MeV, at an angle of 150°.

  11. Proton-Proton Scattering at 105 Mev and 75 Mev

    DOE R&D Accomplishments Database

    Birge, R. W.; Kruse, U. E.; Ramsey, N. F.

    1951-01-31

    The scattering of protons by protons provides an important method for studying the nature of nuclear forces. Recent proton-proton scattering experiments at energies as high as thirty Mev{sup 1} have failed to show any appreciable contribution to the cross section from higher angular momentum states, but it is necessary to bring in tensor forces to explain the magnitude of the observed cross section.

  12. EGRET observations of bursts at MeV energies

    SciTech Connect

    Catelli, J. R.; Schneid, E. J.

    1998-05-16

    We present preliminary results from the analysis of 16 bright bursts that have been observed by the EGRET NaI calorimeter, or TASC. Seven bursts have been imaged in the EGRET spark chamber above 30 MeV, but in most cases the TASC data gives the highest energy spectra available for these bursts. The TASC can obtain spectral and rate information for bursts well outside the field of view of the EGRET spark chambers, and is sensitive in the energy range from 1 to 200 MeV. The spectra for these bursts are mostly consistent with a simple power law with spectral index in the range from 1.7 to 3.7, with several of the brighter bursts showing emission past 100 MeV. No high energy cutoff has been observed. These high energy photons offer important clues to the physical processes involved at the origin of burst emission. For bursts at cosmological distances extremely high bulk Lorentz factors are implied by the presence of MeV and GeV photons which have not been attenuated by pair production with the lower energy photons from the source.

  13. Level Density of COBALT-57 in the Energy Region 1 Mev to 14 Mev

    NASA Astrophysics Data System (ADS)

    Mishra, Vivek

    The level density of ^{57 }Co is studied in the energy region of 1-14 MeV using three experimental techniques. Levels are counted in the resolved region, evaporation spectra are measured in the resolved to continuum region, and the coherence width is measured in the region of level overlap. Use of Hauser-Feshbach fits to the evaporation cross sections requires level densities of the residual nucleus. A two -parameter based Fermi gas form is used for the calculation of level density as a function of the nuclear excitation energy. This procedure enables level density calculation beyond the energy region in which the two fixed parameters provide the best fits to the data. A comparison is made between the level density obtained from the above described methods and the predictions of the microscopic model in an energy range of 1-20 MeV. This model utilizes a BCS pairing Hamiltonian and specific sets of single particle states and calculates numerical values of the level density. Comparisons are also made with level density of ^{57 }Co obtained in various other studies. Both the resolved level studies and the fits to the evaporation spectra were conducted using the ^{56}Fe(d,n)^{57 }Co and ^{57}Fe(p,n) ^{57}Co reactions. Standard neutron time-of-flight techniques including pulse shape discrimination for elimination of gamma -rays were employed. An energy resolution as good as 6 keV at 1-1.5 MeV neutron energy was obtained for high resolution measurements. For Ericson fluctuation measurements, the excitation functions corresponding to the ground state and the first two excited states of the residual nucleus in the ^{56}Fe(p,n) ^{56}Co reaction were obtained for lab angles between 0^circ and 150^circ. The ^{56}Fe(d,n) ^{57}Co reaction proves to be very selective in populating resolved states and includes substantial contributions from mechanisms other than the compound nuclear. The ^{57 }Fe(p,n)^{57}Co reaction populated 14 previously unknown levels. The fits to the

  14. Inclusive proton reactions at 164 MeV

    NASA Astrophysics Data System (ADS)

    Segel, R. E.; Chen, T.; Rutledge, L. L., Jr.; Maher, J. V.; Wiggins, John; Singh, P. P.; Debevec, P. T.

    1982-12-01

    Singles proton, deuteron, triton, 3He, and alpha spectra resulting from the bombardment of 27Al, 58Ni, 62Ni, and 208Pb targets were measured. Data were taken over the angular range 25°-150°. Most of the data were taken at a bombarding energy of 164 MeV; some data were taken at 100 MeV. The ratios of fast (>30 MeV) particle yields are p:d:t:3He:α~100:10:1:1:1. The deuteron spectra fall off more sharply with exit particle energy than do the proton spectra while tritons fall still more sharply, and the fast 3He and α spectra are similar in shape to the triton spectra. Fast particle angular distributions are all forward peaked with the forward peaking increasing with increasing outgoing particle energy. Angular distributions for the different particle species are quite similar and shapes of both spectral and angular distributions are rather independent of target. Proton and alpha evaporation peaks are prominent, deuterons less so, and evaporation peaks are not apparent in the triton and 3He spectra. NUCLEAR REACTIONS 164, 100 MeV p on 27Al, 58Ni, 62Ni, 208Pb; measured outgoing p, d, t, 3He, α spectra 25°<=θ<=150°.

  15. Valine radiolysis by MeV ions

    NASA Astrophysics Data System (ADS)

    Da Silveira, Enio

    2016-07-01

    Valine, (CH3)2 CHCH (NH2) COOH, is a protein amino acid that has been identified in extraterrestrial environments and in the Murchison meteorite [1]. The knowledge of half-lives of small organic molecules under ionizing radiation is important for the setup of models describing the spread out of prebiotics across the Solar System or the Galaxy. We have investigated typical effects of MeV cosmic ray ions on prebiotic molecules in laboratory by impinging ions produced by the PUC-Rio Van de Graaff accelerator. Pure valine films, deposited by evaporation on KBr substrates, were irradiated by H ^{+}, He ^{+} and N ^{+} ion beams, from 0.5 to 1.5 MeV and up to a fluence of 10 ^{15} projectiles/cm ^{2}. The sample temperature was varied from 10 K to 300 K. The irradiation was interrupted several times for Mid-FTIR analysis of the sample. The main findings are: 1- The column density of the valine decreases exponentially with fluence. 2- In some cases, a second exponential appears in the beginning of irradiation; this feature has been attributed to sample compaction by the ion beam [2]. 3- Destruction cross sections of valine are in the 10 ^{-15} cm ^{2} range, while compaction cross sections are in the 10 ^{-14} cm ^{2} range. 4- Destruction cross section increases with the stopping power of the beam and also with the sample temperature. 5- Surprisingly, during the radiolysis of valine, just CO _{2} is seen by as a daughter molecule formed in the bulk. 6- After long beam fluence, also a CO peak appears in the infrared spectrum; this species is however interpreted as a fragment of the formed CO2 molecules. 7- Considering the flux ratio between laboratory experiments and actual galactic cosmic rays, half-life of valine is predicted for ISM conditions [3]. This work on pure valine is the first measurement of a series. New experiments are planned for determining cross sections of valine dissolved in H _{2}O or CO _{2}, inspired by the study performed for glycine [4]. [1] P

  16. MeV neutrinos in double {beta} decay

    SciTech Connect

    Zuber, K.

    1997-08-01

    The effect of Majorana neutrinos in the MeV mass range on the double {beta} decay of various isotopes is studied on pure phenomenological arguments. By using only experimental half-life data, limits on the mixing parameter U{sub eh}{sup 2} of the order 10{sup {minus}7} can be derived. Also the possible achievements of upcoming experiments and some consequences are outlined. {copyright} {ital 1997} {ital The American Physical Society}

  17. XRD study of yttria stabilized zirconia irradiated with 7.3 MeV Fe, 10 MeV I, 16 MeV Au, 200 MeV Xe and 2.2 GeV Au ions

    NASA Astrophysics Data System (ADS)

    Nakano, K.; Yoshizaki, H.; Saitoh, Y.; Ishikawa, N.; Iwase, A.

    2016-03-01

    To simulate energetic neutron irradiation effects, yttria-stabilized zirconia (YSZ) which is one of the major materials for electrical corrosion potential sensors (ECP sensors) was irradiated with heavy ions at energies ranging from 7.3 MeV to 2.2 GeV. Ion irradiation effects on the lattice structure were analyzed using the X-ray diffraction (XRD). The increase in lattice constant was induced by the ion irradiation. It was dominated by the elastic collision process and not by the electronic excitation process. The lattice disordering which was observed as a broadening of XRD peaks was also induced by the irradiation especially for 200 MeV Xe ion irradiation. The present result suggests that the expansion and/or the disordering of YSZ lattice induced by energetic neutrons may affect the durability of a joint interface between a metal housing and YSZ membrane for the usage of ECP sensors in nuclear power reactors.

  18. Observations of gamma radiation between 0.4 MeV and 7 MeV at balloon altitudes using a Compton telescope

    NASA Technical Reports Server (NTRS)

    Lockwood, J. A.; Webber, W. R.; Friling, L. A.; Macri, J.; Hsieh, L.

    1981-01-01

    Balloon-borne measurements of the atmospheric and diffuse gamma-ray flux in the energy range 0.4-7.0 MeV with a Compton telescope, which included pulse-shape discrimination of the first scattering detector and a time-of-flight system between the first and second detector elements, are reported. Comparison of the diffuse cosmic gamma-ray flux to the atmospheric gamma rays indicates that 0.2-5.0 MeV is the optimum energy range for measurements made at the top of the earth's atmosphere. The measured total atmospheric gamma-ray flux between zero and 40 deg has an energy spectrum that agrees with the calculations of Ling (1975). Observations indicate that the ratio of the diffuse to atmospheric gamma ray fluxes at 3.5 g/sq cm is a maximum, about 1.0, between 0.7 and 3.0 MeV.

  19. Measurement of inner radiation belt electrons with kinetic energy above 1 MeV

    NASA Astrophysics Data System (ADS)

    Selesnick, R. S.

    2015-10-01

    Data from the Proton-Electron Telescope on the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) satellite, taken during 1992-2009, are analyzed for evidence of inner radiation belt electrons with kinetic energy E > 1 MeV. It is found that most of the data from a detector combination with a nominal energy threshold of 1 MeV were, in fact, caused by a chance coincidence response to lower energy electrons or high-energy protons. In particular, there was no detection of inner belt or slot region electrons above 1 MeV following the 2003 Halloween storm injection, though they may have been present. However, by restricting data to a less-stable, low-altitude trapping region, a persistent presence of inner belt electrons in the energy range 1 to 1.6 MeV is demonstrated. Their soft, exponential energy spectra are consistent with extrapolation of lower energy measurements.

  20. Measurement of neutron yield by 62 MeV proton beam on a thick beryllium target

    NASA Astrophysics Data System (ADS)

    Osipenko, M.; Ripani, M.; Alba, R.; Ricco, G.; Schillaci, M.; Barbagallo, M.; Boccaccio, P.; Celentano, A.; Colonna, N.; Cosentino, L.; Del Zoppo, A.; Di Pietro, A.; Esposito, J.; Figuera, P.; Finocchiaro, P.; Kostyukov, A.; Maiolino, C.; Santonocito, D.; Scuderi, V.; Viberti, C. M.

    2013-09-01

    The design of a low-power prototype of neutron amplifier recently proposed within the INFN-E project indicated the need for more accurate data on the neutron yield produced by a proton beam with energy of about 70 MeV impinging on a thick beryllium target. Such measurement was performed at the LNS superconducting cyclotron, covering a wide angular range from 0° to 150° and a complete neutron energy interval from thermal to beam energy. Neutrons with energy above 0.5 MeV were measured by liquid scintillators exploiting their time of flight to determine the kinetic energy. For lower energy neutrons, down to thermal energy, a 3He detector was used. The obtained data are in good agreement with previous measurements at 0° using 66 MeV proton beam, covering neutron energies >10 MeV, as well as with measurements at few selected angles using protons of 46, 55 and 113 MeV energy. The present results extend the neutron yield data in the 60-70 MeV beam energy range. A comparison of measured yields to MCNP, FLUKA and Geant4 Monte Carlo simulations was performed.

  1. Photonuclear reaction based high-energy x-ray spectrometer to cover from 2 MeV to 20 MeV.

    PubMed

    Sakata, S; Arikawa, Y; Kojima, S; Ikenouchi, T; Nagai, T; Abe, Y; Inoue, H; Morace, A; Utsugi, M; Kato, R; Nishimura, H; Nakai, M; Shiraga, H; Fujioka, S; Azechi, H

    2014-11-01

    A photonuclear-reaction-based hard x-ray spectrometer is developed to measure the number and energy spectrum of fast electrons generated by interactions between plasma and intense laser light. In this spectrometer, x-rays are converted to neutrons through photonuclear reactions, and the neutrons are counted with a bubble detector that is insensitive to x-rays. The spectrometer consists of a bundle of hard x-ray detectors that respond to different photon-energy ranges. Proof-of-principle experiment was performed on a linear accelerator facility. A quasi-monoenergetic electron bunch (Ne = 1.0 × 10(-6) C, Ee = 16 ± 0.32 MeV) was injected into a 5-mm-thick lead plate. Bremsstrahlung x-rays, which emanate from the lead plate, were measured with the spectrometer. The measured spectral shape and intensity agree fairly well with those computed with a Monte Carlo simulation code. The result shows that high-energy x-rays can be measured absolutely with a photon-counting accuracy of 50%-70% in the energy range from 2 MeV to 20 MeV with a spectral resolution (Δhν/hν) of about 15%. Quantum efficiency of this spectrometer was designed to be 10(-7), 10(-4), 10(-5), respectively, for 2-10, 11-15, and 15-25 MeV of photon energy ranges.

  2. Response of AGATA segmented HPGe detectors to gamma rays up to 15.1 MeV

    NASA Astrophysics Data System (ADS)

    Crespi, F. C. L.; Avigo, R.; Camera, F.; Akkoyun, S.; Ataç, A.; Bazzacco, D.; Bellato, M.; Benzoni, G.; Blasi, N.; Bortolato, D.; Bottoni, S.; Bracco, A.; Brambilla, S.; Bruyneel, B.; Ceruti, S.; Ciemała, M.; Coelli, S.; Eberth, J.; Fanin, C.; Farnea, E.; Gadea, A.; Giaz, A.; Gottardo, A.; Hess, H.; Kmiecik, M.; Leoni, S.; Maj, A.; Mengoni, D.; Michelagnoli, C.; Million, B.; Montanari, D.; Nicolini, R.; Pellegri, L.; Recchia, F.; Reiter, P.; Riboldi, S.; Ur, C. A.; Vandone, V.; Valiente-Dobon, J. J.; Wieland, O.; Wiens, A.; Agata Collaboration

    2013-03-01

    The response of AGATA segmented HPGe detectors to gamma rays in the energy range 2-15 MeV was measured. The 15.1 MeV gamma rays were produced using the reaction d(11B,nγ)12C at Ebeam=19.1 MeV, while gamma rays between 2 and 9 MeV were produced using an Am-Be-Fe radioactive source. The energy resolution and linearity were studied and the energy-to-pulse-height conversion resulted to be linear within 0.05%.Experimental interaction multiplicity distributions are discussed and compared with the results of Geant4 simulations. It is shown that the application of gamma-ray tracking allows a suppression of background radiation caused by n-capture in Ge nuclei. Finally the Doppler correction for the 15.1 MeV gamma line, performed using the position information extracted with Pulse-shape analysis is discussed.

  3. The calibration of photographic and spectroscopic films: The response of 2aO film to small dosages of alpha particles from 3/10th's rad to 8 rads at energy levels 153 MeV, 79 MeV and 47 MeV

    NASA Technical Reports Server (NTRS)

    Hammond, E. C., Jr.; Peters, Kevin; Stober, AL

    1984-01-01

    The 2aO film, pre-exposed to a series of neutral density filters which on development under standard conditions will produce the standard H-D curve for that film, were then exposed to Alpha paricles with a dose range of 3/10ths rads to 8 rads while varying the energy of the particles using 153 MeV, 70 MeV, and 47 MeV, respectively. An analysis of the film shows that the 3/10th rad dose produces the lowest optical density changes at 70 MeV and 47 MeV. While the optical density readings for the darker patterns seem to oscillate and decrease when exposed to radiation dosages of 3/10th rads to 8 rads.

  4. MeV Dark Matter and Small Scale Structure

    SciTech Connect

    Hooper, Dan; Kaplinghat, Manoj; Strigari, Louis E.; Zurek, Kathryn M.; /Wisconsin U., Madison

    2007-04-01

    WIMPs with electroweak scale masses (neutralinos, etc.) remain in kinetic equilibrium with other particle species until temperatures approximately in the range of 10 MeV to 1 GeV, leading to the formation of dark matter substructure with masses as small as 10{sup -4} M{sub {circle_dot}} to 10{sup -12} M{sub {circle_dot}}. However, if dark matter consists of particles with MeV scale masses, as motivated by the observation of 511 keV emission from the Galactic Bulge, such particles are naturally expected to remain in kinetic equilibrium with the cosmic neutrino background until considerably later times. This would lead to a strong suppression of small scale structure with masses below about 10{sup 7}M{sub {circle_dot}} to 10{sup 4} M{sub {circle_dot}}. This cutoff scale has important implications for present and future searches for faint Local Group satellite galaxies and for the missing satellites problem.

  5. X-ray FEL with a meV bandwidth

    NASA Astrophysics Data System (ADS)

    Saldin, E. L.; Schneidmiller, E. A.; Shvyd'ko, Yu. V.; Yurkov, M. V.

    2001-12-01

    A new design for a single pass X-ray Self-Amplified Spontaneous Emission (SASE) FEL was proposed by Feldhaus et al. (Opt. Commun. 140 (1997) 341) and named "two-stage SASE FEL". The scheme consists of two undulators and an X-ray monochromator located between them. For the Angström wavelength range the monochromator can be realized using Bragg reflections from crystals. We propose a scheme of monochromator with a bandwidth of 20 meV for the 14.4 keV X-ray SASE FEL being developed in the framework of the TESLA linear collider project. The spectral bandwidth of the radiation from the two-stage SASE FEL (20 meV) is determined by the finite duration of the electron pulse. The shot-to-shot fluctuations of energy spectral density are dramatically reduced in comparison with the 100% fluctuations in a SASE FEL. The peak and average brilliance are three orders of magnitude higher than the values which could be reached by a conventional X-ray SASE FEL.

  6. Study of {sup 27}Al(n,x{gamma}) reactions up to a neutron energy of 400 MeV

    SciTech Connect

    Hitzenberger, H.; Pavlik, A.; Vonach, H.; Chadwick, M.B.; Haight, R.C.; Nelson, R.O.; Young, P.G.

    1994-06-01

    The prompt {gamma}-radiation from the interaction of fast neutrons with Al was measured using the white neutron beam of the WNR facility at the Los Alamos National Laboratory. Partial production cross sections for residual nuclei in the range from F to Al were measured from threshold up to 400 MeV by observing the most intense {gamma}-transitions between low lying levels of these nuclei. Two-dimensional neutron time-of-flight versus gamma pulse height spectra from the interaction of the neutrons with Al were observed after flight-paths of about 20 and 40 m with a high-purity Ge-detector. The neutron cross sections for prominent {gamma}-transitions in a large number of residual nuclei could be derived with typical uncertainties of 10--20% up to a neutron energy of 400 MeV. The energy resolution varies from {approx}0.2 MeV at 10 MeV to {approx}50 MeV at 400 MeV. In the low energy range (up to 60 MeV) the results are compared with nuclear model calculations using the code GNASH. A very good overall agreement is obtained without special adjustment of parameters.

  7. Upper limit on the inner radiation belt MeV electron intensity

    PubMed Central

    Li, X; Selesnick, RS; Baker, DN; Jaynes, AN; Kanekal, SG; Schiller, Q; Blum, L; Fennell, J; Blake, JB

    2015-01-01

    No instruments in the inner radiation belt are immune from the unforgiving penetration of the highly energetic protons (tens of MeV to GeV). The inner belt proton flux level, however, is relatively stable; thus, for any given instrument, the proton contamination often leads to a certain background noise. Measurements from the Relativistic Electron and Proton Telescope integrated little experiment on board Colorado Student Space Weather Experiment CubeSat, in a low Earth orbit, clearly demonstrate that there exist sub-MeV electrons in the inner belt because their flux level is orders of magnitude higher than the background, while higher-energy electron (>1.6 MeV) measurements cannot be distinguished from the background. Detailed analysis of high-quality measurements from the Relativistic Electron and Proton Telescope on board Van Allen Probes, in a geo-transfer-like orbit, provides, for the first time, quantified upper limits on MeV electron fluxes in various energy ranges in the inner belt. These upper limits are rather different from flux levels in the AE8 and AE9 models, which were developed based on older data sources. For 1.7, 2.5, and 3.3 MeV electrons, the upper limits are about 1 order of magnitude lower than predicted model fluxes. The implication of this difference is profound in that unless there are extreme solar wind conditions, which have not happened yet since the launch of Van Allen Probes, significant enhancements of MeV electrons do not occur in the inner belt even though such enhancements are commonly seen in the outer belt. Key Points Quantified upper limit of MeV electrons in the inner belt Actual MeV electron intensity likely much lower than the upper limit More detailed understanding of relativistic electrons in the magnetosphere PMID:26167446

  8. Search for narrow structures in the anti pp annihilation cross section from 1925 to 1955 MeV

    SciTech Connect

    Lowenstein, D I; Peaslee, D C; Bromberg, C

    1980-01-01

    The anti pp annihilation cross section has been measured over the CM energy range 1925 to 1955 MeV with an RMS resolution of +-2.5 MeV on the average. This search yields no evidence for narrow enhancements in the S(1936) region. Using an A + B/p dependent background, a two standard deviation upper limit of 9 mb-MeV is set for the integrated area of any resonance with mass between 1936 and 1942 and with width less than or equal to 4 MeV.

  9. ETAII 6 MEV PEPPERPOT EMITTANCE MEASUREMENT

    SciTech Connect

    Paul, A C; Richardson, R; Weir, J

    2004-10-18

    We measured the beam emittance at the ETAII accelerator using a pepper-pot diagnostic at nominal parameters of 6 MeV and 2000 Amperes. During the coarse of these experiments, a ''new tune'' was introduced which significantly improved the beam quality. The source of a background pedestal was investigated and eliminated. The measured ''new tune'' emittance is {var_epsilon}= 8.05 {plus_minus} 0. 53 cm - mr or a normalized emittance of {var_epsilon}{sub n} = 943 {plus_minus} 63 mm - mr In 1990 the ETAII programmatic emphasis was on free electron lasers and the paramount parameter was whole beam brightness. The published brightness for ETAII after its first major rebuild was J = 1 - 3 x 10{sup 8} A/(m - rad){sup 2} at a current and energy of 1000-1400 Amperes and 2.5 MeV. The average normalized emittance derived from table 2 of that report is 864 mm-mr corresponding to a real emittance of 14.8 cm-mr.

  10. Absolute polarimeter for the proton-beam energy of 200 MeV

    SciTech Connect

    Zelenski, A. N.; Atoian, G.; Bogdanov, A. A.; Nurushev, S. B.; Pylaev, F. S.; Raparia, D.; Runtso, M. F.; Stephenson, E.

    2013-12-15

    A polarimeter is upgraded and tested in a 200-MeV polarized-proton beam at the accelerator-collider facility of the Brookhaven National Laboratory. The polarimeter is based on the elastic polarizedproton scattering on a carbon target at an angle of 16.2°, in which case the analyzing power is close to unity and was measured to a very high degree of precision. It is shown that, in the energy range of 190–205 MeV, the absolute polarization can be measured to a precision better than ±0.5%.

  11. MeV heavy ion microprobe PIXE for the analysis of the materials surface

    NASA Astrophysics Data System (ADS)

    Mokuno, Y.; Horino, Y.; Kinomura, A.; Chayahara, A.; Kiuchi, M.; Fujii, K.; Takai, M.

    1994-03-01

    Micro PIXE analysis using MeV phosphorus microprobes was performed to a surface structure which consists of multilevel aluminum wirings in silicon nitride and these results were compared with those from a proton microprobe. In the case of a 2 MeV phosphorus microprobe, the X-ray production was enhanced near the surface due to the large energy deposition rate or the short projectile range. As a result, the increase in surface sensitivity was clearly shown in PIXE mapping images of aluminum, silicon, and phosphorus.

  12. The 500-MeV, 2 1/2% duty factor linear electron accelerator (MEA)

    SciTech Connect

    Bruinsma, P.J.T.; Kroes, F.B.; Kuijer, L.H.; Noomen, J.G.; Spelt, J.B.; Vogel, A.G.C.

    1983-08-01

    Although the intermediate energy electron accelerator in Amsterdam has not reached completely its design specifications, since early 1981 a fully grown scientific program has developed using beams with an energy ranging from 20 to 120 MeV in the 140 MeV substation (for radio-chemistry and low-energy electron scattering over 180/sup 0/) and from 70 to 400 MeV in the high energy stations for electron scattering and physics with pion and muon beams. A brief description of the MIT-type accelerator and its performance will be given with emphasis on typical features of the machine. Some examples will be given of recently obtained scientific data from which can be derived that the quality of the beam is in full accordance with the high performance level of the scientific equipment, involving a complex beam transport system and a pair of spectrometers for high resolution (1x10/sup -4/) work.

  13. MeV ion-beam analysis of optical data storage films

    NASA Technical Reports Server (NTRS)

    Leavitt, J. A.; Mcintyre, L. C., Jr.; Lin, Z.

    1993-01-01

    Our objectives are threefold: (1) to accurately characterize optical data storage films by MeV ion-beam analysis (IBA) for ODSC collaborators; (2) to develop new and/or improved analysis techniques; and (3) to expand the capabilities of the IBA facility itself. Using H-1(+), He-4(+), and N-15(++) ion beams in the 1.5 MeV to 10 MeV energy range from a 5.5 MV Van de Graaff accelerator, film thickness (in atoms/sq cm), stoichiometry, impurity concentration profiles, and crystalline structure were determined by Rutherford backscattering (RBS), high-energy backscattering, channeling, nuclear reaction analysis (NRA) and proton induced X-ray emission (PIXE). Most of these techniques are discussed in detail in the ODSC Annual Report (February 17, 1987), p. 74. The PIXE technique is briefly discussed in the ODSC Annual Report (March 15, 1991), p. 23.

  14. Measurement of the Am241(n,2n) reaction cross section from 7.6 MeV to 14.5 MeV

    NASA Astrophysics Data System (ADS)

    Tonchev, A. P.; Angell, C. T.; Boswell, M.; Crowell, A. S.; Fallin, B.; Hammond, S.; Howell, C. R.; Hutcheson, A.; Karwowski, H. J.; Kelley, J. H.; Pedroni, R. S.; Tornow, W.; Becker, J. A.; Dashdorj, D.; Kenneally, J.; Macri, R. A.; Stoyer, M. A.; Wu, C. Y.; Bond, E.; Chadwick, M. B.; Fitzpatrick, J.; Kawano, T.; Rundberg, R. S.; Slemmons, A.; Vieira, D. J.; Wilhelmy, J. B.

    2008-05-01

    The (n,2n) cross section of the radioactive isotope Am241 (T1/2=432.6 y) has been measured in the incident neutron energy range from 7.6 to 14.5 MeV in steps of a few MeV using the activation technique. Monoenergetic neutron beams were produced via the H2(d,n)He3 reaction by bombarding a pressurized deuterium gas cell with an energetic deuteron beam at the TUNL 10-MV Van de Graaff accelerator facility. The induced γ-ray activity of Am240 was measured with high-resolution HPGe detectors. The cross section was determined relative to Al, Ni, and Au neutron activation monitor foils, measured in the same geometry. Good agreement is obtained with previous measurements at around 9 and 14 MeV, whereas for a large discrepancy is observed when our data are compared to those reported by Perdikakis near 11 MeV. Very good agreement is found with the END-B/VII evaluation, whereas the JENDL-3.3 evaluation is in fair agreement with our data.

  15. Cross sections of the (n ,p ) reaction on the 78Se and 80Se isotopes measured for 13.73 MeV to 14.77 MeV and estimated for 10 MeV to 20 MeV neutron energies

    NASA Astrophysics Data System (ADS)

    Attar, F. M. D.; Dhole, S. D.; Bhoraskar, V. N.

    2014-12-01

    The cross sections of 78Se(n ,p ) 78As and 80Se(n ,p ) 80As reactions were measured at five neutron energies over the range 13.73 MeV to 14.77 MeV using 56Fe and 19F as monitor elements, respectively. The cross sections were also theoretically estimated using EMPIRE-II and TALYS codes over 10 MeV to 20 MeV neutrons and matched with the experimental cross sections by making proper choice of the model parameters. The theoretical and experimental cross sections of 80Se(n ,p ) 80As reaction are smaller as compared to the 78Se(n ,p ) 78As reaction at each neutron energy. This difference is attributed to the competing 80Se(n ,2 n )79Se and 80Se( n ,α )Ge77m reactions, which effectively decrease the cross sections of 80Se(n ,p ) 80As reaction as compared to that of the 78Se(n ,p ) 78As reaction over the neutron energy range used in the present work. The cross sections of 78Se(n ,p ) 78As and 80Se(n ,p ) 80As reactions estimated by the EMPIRE-II code initially increase but later on decrease with neutron energy, respectively, above 16 MeV and 19 MeV, whereas those estimated by the TALYS code continuously increase with neutron energy. The present results indicate that the trends in the variation of cross section with neutron energy depend on the model used in the calculations. The cross sections of the 80Se(n ,p ) 80As reaction at different neutron energies reported in the present work can be added as a new data in the nuclear data library.

  16. {sup {bold 6}}Li(vector)+{sup {bold 12}}C inelastic scattering at 30 and 50 MeV

    SciTech Connect

    Kerr, P.L.; Kemper, K.W.; Green, P.V.; Mohajeri, K.; Myers, E.G.; Schmidt, B.G.; Hnizdo, V.

    1996-09-01

    A complete set of analyzing powers (AP`s), {ital iT}{sub 11}, {ital T}{sub 20}, {ital T}{sub 21}, and {ital T}{sub 22}, for 50 MeV {sup 12}C({sup 6}Li(vector),{sup 6}Li) elastic scattering and inelastic scattering to the {sup 12}C(2{sup +}, 4.44 MeV), {sup 12}C(0{sup +}, 7.65 MeV), and {sup 12}C(3{sup {minus}}, 9.64 MeV) states over the center-of-mass (c.m.) angular range 10{degree}{endash}115{degree} is reported. In addition, cross sections for the excited states 3{sup +}(2.18 MeV), 2{sup +}(4.31 MeV), and 1{sup +}(5.65 MeV) of {sup 6}Li were measured by using the inverse-kinematics reaction {sup 6}Li({sup 12}C,{sup 12}C) at 100 MeV. A combined analysis of the new 50 MeV data and previous 30 MeV data has been carried out using the coupled-channels (CC) code FRESCO. The CC calculations use an optical potential with double-folded (DF) real central, Woods-Saxon imaginary central, and Thomas real spin-orbit (SO) potentials. Calculations include reorientation terms and coupling to the first three excited states of {sup 6}Li and the first two nonzerospin states of {sup 12}C. The {sup 6}Li coupling strengths were fixed by the measured {sup 6}Li excited-state cross sections. The elastic-scattering cross sections and A.P.`s are described well. The need for an explicit SO potential is apparent in the elastic and inelastic-scattering AP`s {ital iT}{sub 11}, more so at 30 MeV than at 50 MeV. The rank-2 AP`s up to 50{degree} c.m. arise mainly from ground-state reorientation effects. The DF potential normalization constant {ital N} approaches unity for the 50 MeV data. At both energies, the {sup 12}C(2{sup +}) cross sections are underestimated at large angles, and the description of the {sup 12}C(3{sup {minus}}) cross sections is poor in detail. The {sup 12}C(3{sup {minus}}) AP`s and the {sup 12}C(2{sup +}) {ital iT}{sub 11} are not reproduced at either energy. {copyright} {ital 1996 The American Physical Society.}

  17. Isotopic production cross sections in proton-nucleus collisions at 200 MeV

    SciTech Connect

    Machner, H.; Aschman, D.G.; Steyn, D.; Baruth-Ram, K.; Carter, J.; Sideras-Haddad, E.; Sellschop, J.P.F.; Cowley, A.A.; Goldenbaum, F.; Nangu, B.M.; Spoelstra, B.; Pilcher, J.V.; Smit, F.D.

    2006-04-15

    Intermediate-mass fragments from the interaction of {sup 27}Al, {sup 59}Co, and {sup 197}Au with 200-MeV protons were measured in an angular range from 20 deg. to 120 deg. in the laboratory system. The fragments, ranging from isotopes of helium up to isotopes of carbon, were isotopically resolved. Double-differential cross sections, energy-differential cross sections, and total cross sections were extracted.

  18. Shielding measurements for a 230 MeV proton beam

    SciTech Connect

    Siebers, J.V.

    1990-01-01

    Energetic secondary neutrons produced as protons interact with accelerator components and patients dominate the radiation shielding environment for proton radiotherapy facilities. Due to the scarcity of data describing neutron production, attenuation, absorbed dose, and dose equivalent values, these parameters were measured for 230 MeV proton bombardment of stopping length Al, Fe, and Pb targets at emission angles of 0{degree}, 22{degree}, 45{degree}, and 90{degree} in a thick concrete shield. Low pressure tissue-equivalent proportional counters with volumes ranging from 1 cm{sup 3} to 1000 cm{sup 3} were used to obtain microdosimetric spectra from which absorbed dose and radiation quality are deduced. Does equivalent values and attenuation lengths determined at depth in the shield were found to vary sharply with angle, but were found to be independent of target material. Neutron dose and radiation length values are compared with Monte Carlo neutron transport calculations performed using the Los Alamos High Energy Transport Code (LAHET). Calculations used 230 MeV protons incident upon an Fe target in a shielding geometry similar to that used in the experiment. LAHET calculations overestimated measured attenuation values at 0{degree}, 22{degree}, and 45{degree}, yet correctly predicted the attenuation length at 90{degree}. Comparison of the mean radiation quality estimated with the Monte Carlo calculations with measurements suggest that neutron quality factors should be increased by a factor of 1.4. These results are useful for the shielding design of new facilities as well as for testing neutron production and transport calculations.

  19. Pion Induced Pion Production on Oxygen at 280 Mev.

    NASA Astrophysics Data System (ADS)

    Rozon, Francis Martin

    A first coincident measurement of the pion induced pion production reaction cross-section on a complex nucleus (A > 2) has been successfully performed. In particular, the reaction ^{16}O( pi^+,pi^+pi^-) was measured at 280 MeV incident pion energy. The only previous published measures of this reaction on nuclei consisted of a dated measurement done on emulsion nuclei (BBD*69) and did not provide very stringent limits to the nuclear cross section. Single arm experiments have previously been done elsewhere on the proton (BJK*80) and the deuteron (PGM*84). The reaction was measured at TRIUMF using the QQD magnetic spectrometer in coincidence with the CARUZ (RGR88), a total absorption scintillator range telescope. The measured four-fold differential cross sections were extrapolated to the unmeasured portions of the phase-space to extract the total reaction cross-section at 280 MeV, which was found to be sigma_{tot} = 2.250 +/-.350mb . The (pi,2pi ) cross-section is thus observed to provide approximately 40% of the inclusive double charge exchange cross section (Woo84) at this energy. The model of (OV86) is found to explain many of the features of the data, including sigma _{tot}. The present data do not preclude effects due to pion condensate precursor phenomena as proposed by (CE83) but they do not support the existence of a strong effect. The data are also compared to kinematical Monte Carlo simulations of some possible reaction mechanisms and it is found that the presence of an intermediate Delta can aid the explanation of the low energy features of the pi^+ energy spectrum.

  20. Photonuclear reaction based high-energy x-ray spectrometer to cover from 2 MeV to 20 MeV

    SciTech Connect

    Sakata, S. Arikawa, Y.; Kojima, S.; Ikenouchi, T.; Nagai, T.; Abe, Y.; Inoue, H.; Morace, A.; Utsugi, M.; Nishimura, H.; Nakai, M.; Shiraga, H.; Fujioka, S.; Azechi, H.; Kato, R.

    2014-11-15

    A photonuclear-reaction-based hard x-ray spectrometer is developed to measure the number and energy spectrum of fast electrons generated by interactions between plasma and intense laser light. In this spectrometer, x-rays are converted to neutrons through photonuclear reactions, and the neutrons are counted with a bubble detector that is insensitive to x-rays. The spectrometer consists of a bundle of hard x-ray detectors that respond to different photon-energy ranges. Proof-of-principle experiment was performed on a linear accelerator facility. A quasi-monoenergetic electron bunch (N{sub e} = 1.0 × 10{sup −6} C, E{sub e} = 16 ± 0.32 MeV) was injected into a 5-mm-thick lead plate. Bremsstrahlung x-rays, which emanate from the lead plate, were measured with the spectrometer. The measured spectral shape and intensity agree fairly well with those computed with a Monte Carlo simulation code. The result shows that high-energy x-rays can be measured absolutely with a photon-counting accuracy of 50%–70% in the energy range from 2 MeV to 20 MeV with a spectral resolution (Δhν/hν) of about 15%. Quantum efficiency of this spectrometer was designed to be 10{sup −7}, 10{sup −4}, 10{sup −5}, respectively, for 2–10, 11–15, and 15–25 MeV of photon energy ranges.

  1. Technical Note: On Cerrobend shielding for 18-22 MeV electron beams

    SciTech Connect

    Wojcicka, Jadwiga B.; Yankelevich, Rafael; Werner, Barry Leonard; Lasher, Donette E.

    2008-10-15

    The purpose of this study is to investigate (1) the depth at which the measurement of the block transmission factor should be made, and (2) the level of the transmission of 18 and 22 MeV electron beams through conventional Cerrobend. We measured the block transmission in water phantom as ionization profiles across the beam and as ionization distributions along the central axis of the beam for 18 and 22 MeV electron beams, for cone sizes ranging from 6x10 cm{sup 2} to 25x25 cm{sup 2}. In our analysis, we separated the bremsstrahlung component produced in the Cerrobend block from the component originating in the head in the transmitted dose under the standard Cerrobend block. The block transmission for both beam energies and cone sizes was maximum on the central axis of the beam at depths between 0.4 and 0.7 cm. For the 18 MeV beam, the maximum transmission was 6.2% for the 6x10 cm{sup 2} cone, and 7.4% for the 25x25 cm{sup 2} cone. For the 22 MeV beam, it was 9.5% for the 6x10 cm{sup 2} cone, and 11.3% for the 25x25 cm{sup 2} cone. For the 22 MeV beam and 15x15 cm{sup 2} cone, it takes 2.95 and 1.4 cm of Cerrobend to reduce the maximum block transmission to 5% and 10%, respectively. The maximum dose under a blocked electron beam occurs on the central axis closer to the surface than it does for the open beam, and the block transmission factor should be defined at this shallower depth. To decrease the block transmission factor to the level of 5% on the central axis, electron beams with energy 18 MeV and greater require additional shielding.

  2. Energy monitoring device for 1.5-2.4 MeV electron beams

    NASA Astrophysics Data System (ADS)

    Fuochi, P. G.; Lavalle, M.; Martelli, A.; Kovács, A.; Mehta, K.; Kuntz, F.; Plumeri, S.

    2010-03-01

    An easy-to-use and robust energy monitoring device has been developed for reliable detection of day-to-day small variations in the electron beam energy, a critical parameter for quality control and quality assurance in industrial radiation processing. It has potential for using on-line, thus providing real-time information. Its working principle is based on the measurement of currents, or charges, collected by two aluminium absorbers of specific thicknesses (dependent on the beam energy), insulated from each other and positioned within a faraday cup-style aluminium cage connected to the ground. The device has been extensively tested in the energy range of 4-12 MeV under standard laboratory conditions at Institute of Isotopes and CNR-ISOF using different types of electron accelerators; namely, a TESLA LPR-4 LINAC (3-6 MeV) and a L-band Vickers LINAC (7-12 MeV), respectively. This device has been also tested in high power electron beam radiation processing facilities, one equipped with a 7-MeV LUE-8 linear accelerator used for crosslinking of cables and medical device sterilization, and the other equipped with a 10 MeV Rhodotron TT100 recirculating accelerator used for in-house sterilization of medical devices. In the present work, we have extended the application of this method to still lower energy region, i.e. from 1.5 to 2.4 MeV. Also, we show that such a device is capable of detecting deviation in the beam energy as small as 40 keV.

  3. Neutron production in neutron-induced reactions at 96 MeV on 56Fe and 208Pb

    NASA Astrophysics Data System (ADS)

    Sagrado García, I. C.; Lecolley, J. F.; Lecolley, F. R.; Blideanu, V.; Ban, G.; Fontbonne, J. M.; Itis, G.; Lecouey, J. L.; Lefort, T.; Marie, N.; Steckmeyer, J. C.; Le Brun, C.; Blomgren, J.; Johansson, C.; Klug, J.; Orhn, A.; Mermod, P.; Olsson, N.; Pomp, S.; Osterlund, M.; Tippawan, U.; Prokofiev, A. V.; Nadel-Turonski, P.; Fallot, M.; Foucher, Y.; Guertin, A.; Haddad, F.; Vatre, M.

    2011-10-01

    Double-differential cross sections for neutron production were measured in 96-MeV neutron-induced reactions at The Svedberg Laboratory in Uppsala, Sweden. Measurements for Fe and Pb targets were performed using two independent setups: DECOI-DEMON, time-of-flight telescope dedicated to the detection of emitted neutrons with energies between a few and 50MeV and CLODIA-SCANDAL device devoted to measuring emitted neutrons with energies above 40MeV. Double-differential cross sections were measured for an angular range between 15 and 98 deg and with low-energy thresholds (≈2 MeV). Angular and energy distributions and total neutron emission cross sections have been obtained from those measurements. Results have been compared with predictions given by different models included in several transport codes (MCNPX, GEANT, TALYS, PHITS, and DYWAN) and with other experimental data (the EXFOR database).

  4. Modification of ROSPEC to cover neutrons from thermal to 18 MeV.

    PubMed

    Ing, H; Djeffal, S; Clifford, T; Li, L; Noulty, R; Machrafi, R

    2007-01-01

    Rotating Spectrometer (ROSPEC) is a neutron spectrometer designed to measure neutron energy distributions, and provide accurate neutron dosimetry. It is a completely self-contained unit and measures neutron energy via recoiling protons in gas proportional counters. Each of the four original gas counters is dedicated to a particular neutron energy range dictated by sensitivity to gamma rays at the low energy end of the spectrum and by proton collisions with the counter walls at the high energy end. Introduced originally in 1992, ROSPEC has a proven operational record with a program of continued upgrades. The operating range of the original ROSPEC spans 50 keV-4.5 MeV. The range of the ROSPEC has now been extended down to include epithermal and thermal neutrons by adding two 2 in. (3)He counters. Also, an optional simple scintillation spectrometer was designed to extend the upper limit of ROSPEC up to 18 MeV.

  5. Determination of partial-wave inelasticities for elastic pion-nucleon scattering with the aid of experimental data on π N → ππ N processes in the beam-momentum range 300 < P beam < 500 MeV/ c

    NASA Astrophysics Data System (ADS)

    Kozhevnikov, V. A.; Sherman, S. G.

    2008-11-01

    The partial-wave inelasticity parameters of the amplitude for elastic pion-nucleon scattering are determined with the aid of the phenomenological amplitude for inelastic π N → ππ N processes in the energy range extending to the threshold for the production of two pions. The resulting inelasticity parameters are compared with their counterparts derived from modern partial-wave analyses. The largest inelastic-scattering cross section in the P11 wave is in excellent agreement with the analogous value from the analysis performed at the George Washington University in 2006. For other waves, however, the present results differ in the majority of cases from respective values given by partial-wave analyses (the distinctions are especially large for the isospin-3/2 amplitudes).

  6. MERLIN - A meV Resolution Beamline at the ALS

    SciTech Connect

    Reininger, Ruben; Bozek, John; Chuang, Y.-D.; Howells, Malcolm; Kelez, Nicholas; Prestemon, Soren; Marks, Steve; Warwick, Tony; Hussain, Zahid; Jozwiak, Chris; Lanzara, Alessandra; Hasan, M. Zahid

    2007-01-19

    An ultra-high resolution beamline is being constructed at the Advanced Light Source (ALS) for the study of low energy excitations in strongly correlated systems with the use of high-resolution inelastic scattering and angle-resolved photoemission. This new beamline, given the acronym Merlin (for meV resolution line), will cover the energy range 10-150 eV. The monochromator has fixed entrance and exit slits and a plane mirror that can illuminate a spherical grating at the required angle of incidence (as in the SX-700 mechanism). The monochromator can be operated in two different modes. In the highest resolution mode, the energy scanning requires translating the monochromator chamber (total travel 1.1 m) as well as rotating the grating and the plane mirror in front of the grating. The resolution in this mode is practically determined by the slits width. In the second mode, the scanning requires rotating the grating and the plane mirror. This mode can be used to scan a few eV without a significant resolution loss. The source for the beamline is a 1.9 m long, 90 mm period quasi periodic EPU. The expected flux at the sample is higher than 1011 photons/s at a resolving power of 5 x 104 in the energy range 16-130 eV. A second set of gratings can be used to obtain higher flux at the expense of resolution.

  7. Two nucleon systems at mπ~450MeV from lattice QCD

    DOE PAGES

    Orginos, Kostas; Parreño, Assumpta; Savage, Martin J.; Beane, Silas R.; Chang, Emmanuel; Detmold, William

    2015-12-23

    Nucleon-nucleon systems are studied with lattice quantum chromodynamics at a pion mass ofmore » $$m_\\pi\\sim 450~{\\rm MeV}$$ in three spatial volumes using $n_f=2+1$ flavors of light quarks. At the quark masses employed in this work, the deuteron binding energy is calculated to be $$B_d = 14.4^{+3.2}_{-2.6} ~{\\rm MeV}$$, while the dineutron is bound by $$B_{nn} = 12.5^{+3.0}_{-5.0}~{\\rm MeV}$$. Over the range of energies that are studied, the S-wave scattering phase shifts calculated in the 1S0 and 3S1-3D1 channels are found to be similar to those in nature, and indicate repulsive short-range components of the interactions, consistent with phenomenological nucleon-nucleon interactions. In both channels, the phase shifts are determined at three energies that lie within the radius of convergence of the effective range expansion, allowing for constraints to be placed on the inverse scattering lengths and effective ranges. Thus, the extracted phase shifts allow for matching to nuclear effective field theories, from which low energy counterterms are extracted and issues of convergence are investigated. As part of the analysis, a detailed investigation of the single hadron sector is performed, enabling a precise determination of the violation of the Gell-Mann–Okubo mass relation.« less

  8. Scintillation detector efficiencies for neutrons in the energy region above 20 MeV

    SciTech Connect

    Dickens, J.K.

    1991-01-01

    The computer program SCINFUL (for SCINtillator FUL1 response) is a program designed to provide a calculated complete pulse-height response anticipated for neutrons being detected by either an NE-213 (liquid) scintillator or an NE-110 (solid) scintillator in the shape of a right circular cylinder. The point neutron source may be placed at any location with respect to the detector, even inside of it. The neutron source may be monoenergetic, or Maxwellian distributed, or distributed between chosen lower and upper bounds. The calculational method uses Monte Carlo techniques, and it is relativistically correct. Extensive comparisons with a variety of experimental data have been made. There is generally overall good agreement (less than 10% differences) of results for SCINFUL calculations with measured integral detector efficiencies for the design incident neutron energy range of 0.1 to 80 MeV. Calculations of differential detector responses, i.e. yield versus response pulse height, are generally within about 5% on the average for incident neutron energies between 16 and 50 MeV and for the upper 70% of the response pulse height. For incident neutron energies between 50 and 80 MeV, the calculated shape of the response agrees with measurements, but the calculations tend to underpredict the absolute values of the measured responses. Extension of the program to compute responses for incident neutron energies greater than 80 MeV will require new experimental data on neutron interactions with carbon. 32 refs., 6 figs., 2 tabs.

  9. Neutron-induced fission cross sections of 242Pu from 0.3 MeV to 3 MeV

    NASA Astrophysics Data System (ADS)

    Salvador-Castiñeira, P.; Bryś, T.; Eykens, R.; Hambsch, F.-J.; Göök, A.; Moens, A.; Oberstedt, S.; Sibbens, G.; Vanleeuw, D.; Vidali, M.; Pretel, C.

    2015-10-01

    The majority of the next generation of nuclear power plants (GEN-IV) will work in the fast-neutron-energy region, as opposed to present day thermal reactors. This leads to new and more accurate nuclear-data needs for some minor actinides and structural materials. Following those upcoming demands, the Organisation for Economic Cooperation and Development Nuclear Energy Agency performed a sensitivity study. Based on the latter, an improvement in accuracy from the present 20% to 5% is required for the 242Pu(n ,f ) cross section. Within the same project both the 240Pu(n ,f ) cross section and the 242Pu(n ,f ) cross section were measured at the Van de Graaff accelerator of the Joint Research Centre at the Institute for Reference Materials and Measurements, where quasimonoenergetic neutrons were produced in an energy range from 0.3 MeV up to 3 MeV. A twin Frisch-grid ionization chamber has been used in a back-to-back configuration as fission-fragment detector. The 242Pu(n ,f ) cross section has been normalized to three different isotopes: 237Np(n ,f ) , 235U(n ,f ) , and 238U(n ,f ) . A comprehensive study of the corrections applied to the data and the uncertainties associated is given. The results obtained are in agreement with previous experimental data at the threshold region up to 0.8 MeV. The resonance-like structure at 0.8 to 1.1 MeV, visible in the evaluations and in most previous experimental values, was not reproduced with the same intensity in this experiment. For neutron energies higher than 1.1 MeV, the results of this experiment are slightly lower than the Evaluated Nuclear Data File/B-VII.1 evaluation but in agreement with the experiment of Tovesson et al. (2009) as well as Staples and Morley (1998). Finally, for energies above 1.5 MeV, the results show consistency with the present evaluations.

  10. Neutron total and scattering cross sections of /sup 6/Li in the few MeV region

    SciTech Connect

    Smith, A.; Guenther, P.; Whalen, J.

    1980-02-01

    Neutron total cross sections of /sup 6/Li are measured from approx. 0.5 to approx. 4.8 MeV at intervals of approx.< 10 keV. Neutron differential elastic-scattering cross sections are measured from 1.5 to 4.0 MeV at approx.> 10 scattering angles and at incident-neutron intervals of approx.< 100 keV. Neutron differential inelastic-scattering cross sections are measured in the incident-energy range 3.5 to 4.0 MeV. The experimental results are extended to lower energies using measured neutron total cross sections recently reported elsewhere by the authors. The composite experimental data (total cross sections from 0.1 to 4.8 MeV and scattering cross sections from 0.22 to 4.0 MeV) are interpreted in terms of a simple two-level R-matrix model which describes the observed cross sections and implies the reaction cross section in unobserved channels; notably the (n;..cap alpha..)t reaction (Q = 4.783 MeV). The experimental and calculational results are compared with previously reported results as summarized in the ENDF/B-V evaluated nuclear data file.

  11. Response of detector modules of the neutron hodoscope SENECA to neutrons with energies 7-70 MeV

    NASA Astrophysics Data System (ADS)

    v. Edel, G.; Selke, O.; Pöch, C.; Smend, F.; Schumacher, M.; Nolte, R.; Schrewe, U.; Brede, H. J.; Schuhmacher, H.; Henneck, R.

    1993-07-01

    SENECA is a hodoscope for recoil neutrons from photoreactions on nuclei and nucleons in the photon energy range 50-900 MeV. It consists of 32 hexagonal scintillation detector modules in a honeycomb array. Differential detection efficiency spectra of a single module as well as the cross-talk between neighbouring modules were measured at neutron energies between 7 and 70 MeV. Neutron detection efficiencies were determined in the same energy range with an average experimental uncertainty of 7.6%. The experimental results agree with predictions from Monte Carlo codes within the limits of the experimental error.

  12. rvec p + sup 13 rvec C elastic scattering at 500 MeV

    SciTech Connect

    Tanaka, N.

    1990-01-01

    For the first time, an elastic scattering experiment was performed at LAMPF using polarized protons and a polarized target nucleus ({rvec p} + {sup 13}{rvec C}). The analyzing powers (A{sub ooon}({Theta})) and (A{sub oonn}({Theta})) were measured using an incident beam energy of 500 MeV over the laboratory angular range of 10{degree}--30{degree}. Motivation for the experiment and some preliminary results and conclusions are presented. 12 refs., 7 figs.

  13. Gamma radiation from the Crab nebula above 35 MeV

    NASA Technical Reports Server (NTRS)

    Kniffen, D. A.; Hartman, R. C.; Thompson, D. J.; Bignami, G. F.; Fichtel, C. E.; Oegelman, H.; Tuemer, T.

    1974-01-01

    Electromagnetic radiation from the Crab nebula were observed, showing that the Crab is unique among strong X-ray sources in that major component in the low energy range (1 to 10 KeV) shows little or no temporal variation. Observations of the Crab above 35 MeV were made with the high energy gamma ray telescope flown on SAS-2. The detector and technique are described in detail.

  14. Ion desorption from frozen H 2O irradiated by MeV heavy ions

    NASA Astrophysics Data System (ADS)

    Collado, V. M.; Farenzena, L. S.; Ponciano, C. R.; Silveira, E. F. da; Wien, K.

    2004-10-01

    Nitrogen (0.13-0.85 MeV) and 252Cf fission fragments (˜65 MeV) beams are employed to sputter positive and negative secondary ions from frozen water. Desorption yields are measured for different ice temperatures and projectile energies. Target surface is continuously refreshed by condensed water while the target temperature varies and ice thickness changes. In both projectile energy ranges, the preferentially ejected ions are H +, H2+ and (H 2O) nH +-cluster ions. The yields of the corresponding negative ions H - and (H 2O) nO - or (H 2O) nOH - are 1-2 orders of magnitude lower. The (H 2O) nH + desorption yields decrease exponentially as the cluster size, n, increases. In the low energy range, the desorption of positive ion clusters may occur in a two-step process: first, desorption of preformed H 2O clusters and, then, ionization by H + or H 3O + capture. For 0.81 MeV N + projectile ions, the cluster ion emission contributes with 0.05% to the total H 2O desorbed yield. There are indications that emission of the (H 2O) nH + disappears for an electronic energy loss lower than 20 eV/Å. For the high energy range, desorption of small ion clusters is particularly enhanced, revealing that a fragmentation process also exists.

  15. X-ray FEL with a meV bandwidth

    NASA Astrophysics Data System (ADS)

    Saldin, E. L.; Schneidmiller, E. A.; Shvyd'ko, Yu. V.; Yurkov, M. V.

    2001-08-01

    A new design for a single pass X-ray Self-Amplified Spontaneous Emission (SASE) FEL was proposed in [1] and named two-stage SASE FEL. The scheme consists of two undulators and an X-ray monochromator located between them. For the Angström wavelength range the monochromator could be realized using Bragg reflections from crystals. Proposed scheme of monochromator is illustrated for the 14.4 keV X-ray SASE FEL being developed in the framework of the TESLA linear collider project. The spectral bandwidth of the radiation from the two-stage SASE FEL (20 meV) is defined by the finite duration of the electron pulse. The shot-to-shot fluctuations of energy spectral density are dramatically reduced in comparison with the 100% fluctuations in a SASE FEL. The peak and average brilliance are by three orders of magnitude higher than the values which could be reached by a conventional X-ray SASE FEL.

  16. Emittance measurements in Grumman 1 MeV beamline

    SciTech Connect

    Debiak, T.; Gammel, G.; Melnychuk, S.

    1992-12-01

    The emittance of a 30 keV H{sup {minus}} beam has been measured with an Allison type electrostatic analyser at two positions separated by 85 cm along the Grumman 1 MeV beamline LEBT at low currents (about 4 mA, no Cs{sub 2}O additive in the source) and at higher currents (10-15 mA, with Cs{sub 2}O additive in the source). No emittance growth was observed between the two positions, but, at the higher current level, the emittance was about 60% higher than at the low current level ({Sigma}{sub n},rms = .0045 {pi} cm-mrad vs. 0070 {pi} cm-mrad). Argon was then introduced up to a partial pressure of 4x10{sup {minus}5} torr, and the emittance decreased back to a range corresponding to that found at the lower currents. However, beam noise was observed at the downstream position, and there is evidence for a small amount of emittance growth (<20%) between the two positions.

  17. Probing the Cosmic X-Ray and MeV Gamma-Ray Background Radiation through the Anisotropy

    SciTech Connect

    Inoue, Yoshiyuki; Murase, Kohta; Madejski, Grzegorz M.; Uchiyama, Yasunobu

    2013-09-24

    While the cosmic soft X-ray background is very likely to originate from individual Seyfert galaxies, the origin of the cosmic hard X-ray and MeV gamma-ray background is not fully understood. It is expected that Seyferts including Compton thick population may explain the cosmic hard X-ray background. At MeV energy range, Seyferts having non-thermal electrons in coronae above accretion disks or MeV blazars may explain the background radiation. We propose that future measurements of the angular power spectra of anisotropy of the cosmic X-ray and MeV gamma-ray backgrounds will be key to deciphering these backgrounds and the evolution of active galactic nuclei (AGNs). As AGNs trace the cosmic large-scale structure, spatial clustering of AGNs exists. We show that e-ROSITA will clearly detect the correlation signal of unresolved Seyferts at 0.5-2 keV and 2-10 keV bands and will be able to measure the bias parameter of AGNs at both bands. Once the future hard X-ray all sky satellites achieve the sensitivity better than 10-12 erg/cm2/s-1 at 10-30 keV or 30-50 keV - although this is beyond the sensitivities of current hard X-ray all sky monitors - angular power spectra will allow us to independently investigate the fraction of Compton-thick AGNs in all Seyferts. We also find that the expected angular power spectra of Seyferts and blazars in the MeV range are different by about an order of magnitude, where the Poisson term, so-called shot noise, is dominant. Current and future MeV instruments will clearly disentangle the origin of the MeV gamma-ray background through the angular power spectrum.

  18. Gamma-ray astronomy in the medium energy (10-50 MeV) range

    NASA Technical Reports Server (NTRS)

    Kniffen, D. A.; Bertsch, D. L.; Morris, D. J.; Palmeira, R. A. R.; Rao, K. R.

    1977-01-01

    To observe the medium energy component of the intense galactic center gamma-ray emission, two balloon flights of a medium energy gamma-ray spark chamber telescope were flown in Brazil in 1975. The results indicate the emission is higher than previously thought and above the predictions of a theoretical model proposed.

  19. Effects of MeV ion beam on polymers

    SciTech Connect

    Evelyn, A.L.; Ila, D.; Zimmerman, R.L.; Bhat, K.; Poker, D.B.; Hensley, D.K.

    1997-12-01

    The electronic ({var_epsilon}{sub c}) and nuclear ({var_epsilon}{sub n}) stopping effects produced by 3.5 MeV and 5.0 MeV ion bombardment in polyvinylidine chloride (PVDC), polyethylene (PE) and polyethylene sulfide were studied and compared. To separate these effects the authors chose two bombardment energies and a thin film polymer stacking technique developed in house. The resulting stacked layered system consisting of each polymer was bombarded with 3.5 MeV and 5.0 MeV alpha particles. The layered system was selected such that the first few layers experience most of the effects of the electronic energy deposited and the last layer receives the effects of the nuclear stopping. The electrical conductance and the changes in the chemical structure were measured by direct resistivity measurements, Raman microprobe analysis, RBS, and FTIR. The post-irradiation characterization resolved the effects of the stopping powers on the polymer films.

  20. Production of 14 MeV neutrons by heavy ions

    DOEpatents

    Brugger, Robert M.; Miller, Lowell G.; Young, Robert C.

    1977-01-01

    This invention relates to a neutron generator and a method for the production of 14 MeV neutrons. Heavy ions are accelerated to impinge upon a target mixture of deuterium and tritium to produce recoil atoms of deuterium and tritium. These recoil atoms have a sufficient energy such that they interact with other atoms of tritium or deuterium in the target mixture to produce approximately 14 MeV neutrons.

  1. Time-dependent 2.2 MeV and 0.5 MeV lines from solar flares

    NASA Technical Reports Server (NTRS)

    Wang, H. T.; Ramaty, R.

    1975-01-01

    The time dependences of the 2.2 MeV and 0.51 MeV gamma ray lines from solar flares are calculated and the results are compared with observations of the 1972, August 4 and 7 flares. Time lag between the nuclear reactions and the formation of these two lines are caused, respectively, by capture of the neutrons, and by deceleration of the positrons and decay of the radioactive nuclei. Results show that the calculation is consistent with the observed rise of the 2.2 MeV line on August 4, and it does not require different time dependences for the accelerated protons and electrons in the flare region. The above lags can explain the delayed gamma ray emission observed on August 7. Positrons of energies greater than about 10 MeV could be detected in interplanetary space following large solar flares.

  2. Celestial diffuse gamma radiation above 30 MeV observed by SAS-2

    NASA Technical Reports Server (NTRS)

    Fichtel, C. E.; Kniffen, D. A.; Hartman, R. C.

    1973-01-01

    The Small Astronomy Satellite (SAS)-2, launched on November 15, 1972, carried into orbit a 32-deck magnetic-core digitized spark chamber gamma ray telescope to study celestial gamma radiation in the energy range above 30 MeV. In the study of several regions with b sub 2 15 deg, a finite, diffuse flux of gamma rays with a steep energy spectrum in the energy region from 35 to 200 MeV is observed. Representing the energy spectrum by a power law of the form dJ/dE = AE to - alpha power over this energy range, alpha is found along with the integral flux above 100 MeV. Combining this result with existing low energy gamma ray data yields an energy spectrum which is not a simple power law in energy, as in the X-ray region, but which demonstrates first an increase and then a decrease in slope, consistent within uncertainties with that predicted by cosmological theories, including the continuous production of high energy gamma rays primarily from neutral pi mesons throughout the history of the universe.

  3. The response of CR-39 nuclear track detector to 1-9 MeV protons

    SciTech Connect

    Sinenian, N.; Rosenberg, M. J.; Manuel, M.; McDuffee, S. C.; Casey, D. T.; Zylstra, A. B.; Rinderknecht, H. G.; Johnson, M. Gatu; Seguin, F. H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D.

    2011-10-28

    The response of CR-39 nuclear track detector (TasTrak®) to protons in the energy range of 0.92-9.28 MeV has been studied. Previous studies of the CR-39 response to protons have been extended by examining the piece-to-piece variability in addition to the effects of etch time and etchant temperature; it is shown that the shape of the CR-39 response curve to protons can vary from piece-to-piece. The effects due to the age of CR-39 have also been studied using 5.5 MeV alpha particles over a 5-year period. Track diameters were found to degrade with the age of the CR-39 itself rather than the age of the tracks, consistent with previous studies utilizing different CR-39 over shorter time periods.

  4. The response of CR-39 nuclear track detector to 1-9 MeV protons

    SciTech Connect

    Sinenian, N.; Rosenberg, M. J.; Manuel, M.; McDuffee, S. C.; Casey, D. T.; Zylstra, A. B.; Rinderknecht, H. G.; Gatu Johnson, M.; Seguin, F. H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D.

    2011-10-15

    The response of CR-39 nuclear track detector (TasTrak) to protons in the energy range of 0.92-9.28 MeV has been studied. Previous studies of the CR-39 response to protons have been extended by examining the piece-to-piece variability in addition to the effects of etch time and etchant temperature; it is shown that the shape of the CR-39 response curve to protons can vary from piece-to-piece. Effects due to the age of CR-39 have also been studied using 5.5 MeV alpha particles over a 5-year period. Track diameters were found to degrade with the age of the CR-39 itself rather than the age of the tracks, consistent with previous studies utilizing different CR-39 over shorter time periods.

  5. The response of CR-39 nuclear track detector to 1-9 MeV protons

    DOE PAGES

    Sinenian, N.; Rosenberg, M. J.; Manuel, M.; McDuffee, S. C.; Casey, D. T.; Zylstra, A. B.; Rinderknecht, H. G.; Johnson, M. Gatu; Seguin, F. H.; Frenje, J. A.; et al

    2011-10-28

    The response of CR-39 nuclear track detector (TasTrak®) to protons in the energy range of 0.92-9.28 MeV has been studied. Previous studies of the CR-39 response to protons have been extended by examining the piece-to-piece variability in addition to the effects of etch time and etchant temperature; it is shown that the shape of the CR-39 response curve to protons can vary from piece-to-piece. The effects due to the age of CR-39 have also been studied using 5.5 MeV alpha particles over a 5-year period. Track diameters were found to degrade with the age of the CR-39 itself rather thanmore » the age of the tracks, consistent with previous studies utilizing different CR-39 over shorter time periods.« less

  6. Exclusive measurements of light fragment production at forward angles in Ne-Pb and Ne-NaF collisions at E/A=400 MeV and 800 MeV

    NASA Technical Reports Server (NTRS)

    Bastid, N.; Alard, J. P.; Arnold, J.; Augerat, J.; Babinet, R.; Biagi, F.; Brochard, F.; Crouau, M.; Charmensat, P.; Dupieux, P.; et, a. l.; Schimmerling, W. (Principal Investigator)

    1990-01-01

    Emission of light fragments at small angles is studied in relativistic heavy ion collisions using the Diogene plastic wall for both symmetrical and non-symmetrical target-projectile systems with 400 MeV per nucleon and 800 MeV per nucleon incident neon nuclei. Efficiency of multiplicity measurements in the small angle range for the selection of central or peripheral collisions is confirmed for asymmetric systems. Differential production cross sections of Z = 1 fragments show evidence for the existence of two emitting sources. The apparent temperature of each source is obtained from comparison with a thermodynamical model.

  7. (19)F(α,n) thick target yield from 3.5 to 10.0 MeV.

    PubMed

    Norman, E B; Chupp, T E; Lesko, K T; Grant, P J; Woodruff, G L

    2015-09-01

    Using a target of PbF2, the thick-target yield from the (19)F(α,n) reaction was measured from E(α)=3.5-10 MeV. From these results, we infer the thick-target neutron yields from targets of F2 and UF6 over this same alpha-particle energy range.

  8. A comparison of radiation damage in transistors from cobalt-60 gamma rays and 2.2 MeV electrons

    NASA Technical Reports Server (NTRS)

    Nichols, D. K.; Price, W. E.; Gauthier, M. K.

    1982-01-01

    The total ionizing dose response of ten bipolar transistor types has been measured using Co-60 gamma rays and 2.2 MeV electrons from exposure levels of 750, 1500, and 3000 Gy(Si). Gain measurements were made for a range of collector-emitter voltages and collector currents.

  9. The thick-target sup 9 Be(d,n) neutron spectra for deuteron energies between 2. 6 and 7. 0-MeV

    SciTech Connect

    Meadows, J.W.

    1991-11-01

    The measurement of the zero deg. neutron spectra and yields from deuterons incident on thick beryllium metal targets is described. {sup 235}U and {sup 238}U fission ion chambers were used as neutron detectors to span the neutron energy range above 0.05-MeV with a time resolution of {le} 3 nanosec. Measurements were made for incident deuteron energies from 2.6 to 7.0-MeV, at 0.4-MeV intervals, using time-of-flight techniques with flight paths of 2.7 and 6.8 meters. The results are presented in graphical form and in tables.

  10. The thick-target {sup 9}Be(d,n) neutron spectra for deuteron energies between 2.6 and 7.0-MeV

    SciTech Connect

    Meadows, J.W.

    1991-11-01

    The measurement of the zero deg. neutron spectra and yields from deuterons incident on thick beryllium metal targets is described. {sup 235}U and {sup 238}U fission ion chambers were used as neutron detectors to span the neutron energy range above 0.05-MeV with a time resolution of {le} 3 nanosec. Measurements were made for incident deuteron energies from 2.6 to 7.0-MeV, at 0.4-MeV intervals, using time-of-flight techniques with flight paths of 2.7 and 6.8 meters. The results are presented in graphical form and in tables.

  11. Proton-induced cross sections relevant to production of 225Ac and 223Ra in natural thorium targets below 200 MeV.

    PubMed

    Weidner, J W; Mashnik, S G; John, K D; Hemez, F; Ballard, B; Bach, H; Birnbaum, E R; Bitteker, L J; Couture, A; Dry, D; Fassbender, M E; Gulley, M S; Jackman, K R; Ullmann, J L; Wolfsberg, L E; Nortier, F M

    2012-11-01

    Cross sections for (223,)(225)Ra, (225)Ac and (227)Th production by the proton bombardment of natural thorium targets were measured at proton energies below 200 MeV. Our measurements are in good agreement with previously published data and offer a complete excitation function for (223,)(225)Ra in the energy range above 90 MeV. Comparison of theoretical predictions with the experimental data shows reasonable-to-good agreement. Results indicate that accelerator-based production of (225)Ac and (223)Ra below 200 MeV is a viable production method.

  12. Proton-induced cross sections relevant to production of 225Ac and 223Ra in natural thorium targets below 200 MeV.

    PubMed

    Weidner, J W; Mashnik, S G; John, K D; Hemez, F; Ballard, B; Bach, H; Birnbaum, E R; Bitteker, L J; Couture, A; Dry, D; Fassbender, M E; Gulley, M S; Jackman, K R; Ullmann, J L; Wolfsberg, L E; Nortier, F M

    2012-11-01

    Cross sections for (223,)(225)Ra, (225)Ac and (227)Th production by the proton bombardment of natural thorium targets were measured at proton energies below 200 MeV. Our measurements are in good agreement with previously published data and offer a complete excitation function for (223,)(225)Ra in the energy range above 90 MeV. Comparison of theoretical predictions with the experimental data shows reasonable-to-good agreement. Results indicate that accelerator-based production of (225)Ac and (223)Ra below 200 MeV is a viable production method. PMID:22940414

  13. Proton-induced production of residual radionuclides in natRe up to 2590 MeV

    NASA Astrophysics Data System (ADS)

    Issa, Shams A. M.; Uosif, M. A. M.; Michel, R.; Herpers, U.; Malmborg, P.; Holmqvist, B.

    2013-03-01

    The excitation functions for residual nuclide production by proton reactions on rhenium was investigated using activated targets from irradiation experiments at the cyclotron of the Svedberg Laboratory at Uppsala up to 180 MeV and the higher energies were used at the Laboratoire Saturne at Saclay. The measured experimental results were compared with previous published and theoretical models calculations by the codes TALYS, INCL4+ABLA and Bertini/Dresner. A total of 5252 cross-section was determined covering 54 residual nuclides in the energy range from 78.2 to 2590 MeV.

  14. Correlation between laser accelerated MeV proton and electron beams using simple fluid model for target normal sheath acceleration

    SciTech Connect

    Tampo, M.; Awano, S.; Nakamura, H.; Nakatsutsumi, M.; Tanimoto, T.; Yabuuchi, T.; Bolton, P. R.; Kondo, K.; Mima, K.; Mori, Y.; Stephens, R. B.; Tanaka, K. A.; Kodama, R.

    2010-07-15

    High density energetic electrons that are created by intense laser plasma interactions drive MeV proton acceleration. The correlation between accelerated MeV protons and escaped electrons is experimentally investigated at laser intensities in the range of 10{sup 18}-10{sup 19} W/cm{sup 2} with S-polarization. Observed proton maximum energies are linearly proportional to escaped electron slope temperatures with a scaling coefficient of about 10. In the context of the simple analytical fluid model for transverse normal sheath acceleration, hot electron sheath density near the target rear surface can be estimated if an empirical acceleration time is assumed.

  15. Results of using the axisymmetric RF focusing by means of field spatial harmonics at 7 MeV proton linac

    NASA Astrophysics Data System (ADS)

    Dyubkov, V. S.

    2016-09-01

    For several decades, axially symmetric channels with RF focusing by means of nonsynchronous spatial harmonics of the accelerating field are offered as an attractive alternative to proven and reliable RFQ linacs. In a number of works an effectiveness of channels with axially symmetric RF focusing by means of the nonsynchronous harmonics of the field was demonstrated in the proton energy range up to 2 MeV. An effectiveness of discussed channels for protons at energies up to 7 MeV is considered in this paper. Numerical simulation results of proton self-consistent dynamics in a channel with axisymmetric RF focusing are presented and discussed in this article.

  16. Design and experiments of RF transverse focusing in S-Band, 1 MeV standing wave linac

    NASA Astrophysics Data System (ADS)

    Mondal, J.; Chandan, Shiv; Parashar, S.; Bhattacharjee, D.; Tillu, A. R.; Tiwari, R.; Jayapraksh, D.; Yadav, V.; Banerjee, S.; Choudhury, N.; Ghodke, S. R.; Dixit, K. P.; Nimje, V. T.

    2015-09-01

    S-Band standing wave (SW) linacs in the range of 1-10 MeV have many potential industrial applications world wide. In order to mitigate the industrial requirement it is required to reduce the overall size and weight of the system. On this context a 2856 M Hz, 1 Me V, bi-periodic on axis coupled self transverse focused SW linac has been designed and tested. The RF phase focusing is achieved by introducing an asymmetric field distribution in the first cell of the 1 MeV linac. The pulsed electron beam of 40 keV, 650 mA and 5 μs duration is injected from a LaB6 thermionic gun. This paper presents the structure design, beam dynamics simulation, fabrication and experimental results of the 1 MeV auto-focusing SW linac.

  17. A measurement of cosmic-ray beryllium isotopes from 200 to 1500 MeV per nucleon

    NASA Technical Reports Server (NTRS)

    Buffington, A.; Orth, C. D.; Mast, T. S.

    1978-01-01

    A balloon-borne superconducting magnetic spectrometer was used in the measurement of cosmic-ray isotopic abundances from lithium through oxygen in the energy range 200-1500 MeV per nucleon. Except for Be-7 all isotopic composition is essentially energy-independent. Be-10 is nearly absent, indicating a mean cosmic-ray age of 6(-3, +10) x 10 to the 6th years. Above about 500 MeV per nucleon, Be-7 drops dramatically in abundance relative to Be-9 and C. By 1500 MeV per nucleon, the relative abundance of Be-7 has become one-half of its lower-energy value. Since Be-7 is the only isotope measured which decays by electron capture, this result is interpreted as indicating that higher-energy Be-7 had an appreciable probability of not being stripped of all its electrons before entering interstellar space where electron pickup is negligible.

  18. Neutron propagation and 2.2 MeV gamma-ray line production in the solar atmosphere

    NASA Technical Reports Server (NTRS)

    Wang, H. T.; Ramaty, R.

    1974-01-01

    The 2.2 MeV gamma ray line intensity from the sun was calculated using a Monte Carlo method for neutron propagation in the solar atmosphere. Detailed results are provided on the total gamma ray yield per neutron and on the time profile of the 2.2 MeV line from an instantaneous and monoenergetic neutron source. The parameters which have the most significant effects on the line intensity are the energies of the neutrons, the position of the neutron source on the sun, and the abundance of He-3 in the photosphere. For an isotropic neutron source which is not too close to the limb of the sun, the gamma ray yield is between about 0.02 to 0.2 photons per neutron, provided that the neutron energies are in the range 1 to 100 MeV and the ratio He-3/H is less than about .00005.

  19. Solar Gamma Rays Above 8 MeV

    NASA Technical Reports Server (NTRS)

    Crannell, C. J.; Crannell, H.; Ramaty, R.

    1978-01-01

    Processes which lead to the production of gamma rays with energy greater than 8 MeV in solar flares are reviewed and evaluated. Excited states produced by inelastic scattering, charge exchange, and spallation reactions in the abundant nuclear species are considered in order to identify nuclear lines which may contribute to the Gamma ray spectrum of solar flares. The flux of 15.11 MeV Gamma rays relative to the flux of 4.44 MeV Gamma rays from the de-excitation of the corresponding states in C12 is calculated for a number of assumed distributions of exciting particles. This flux ratio is a sensitive diagnostic of accelerated particle spectra. Other high energy nuclear levels are not so isolated as the 15.11 MeV state and are not expected to be so strong. The spectrum of Gamma rays from the decay of Pi dey is sensitive to the energy distribution of particles accelerated to energies greater than 100 MeV.

  20. FTIR analysis of polyethylene terephthalate irradiated by MeV He+

    NASA Astrophysics Data System (ADS)

    Djebara, M.; Stoquert, J. P.; Abdesselam, M.; Muller, D.; Chami, A. C.

    2012-03-01

    The degradation induced by MeV He+ ions onto polyethylene terephthalate (PET) is investigated as a function of fluence and electronic stopping power (dE/dx)e. Stack samples of four 3.6 μm PET films are irradiated by 3.5 MeV He+ under vacuum and room temperature at fluence ranging from 1013 to 1.5 × 1015 He+ cm-2. The entrance energies range from 3.5 MeV for the front film to 0.573 MeV for the rear one at the beginning of the irradiation and the corresponding mean (dE/dx)e lie for pristine PET between 158 and 264 keV/μm. A Fourier transform infrared spectroscopy (FTIR) analysis is undertaken. The different stack films present similar damages with magnitude increase as the fluence goes up. Moreover, higher is the electronic stopping power (dE/dx)e more important is the damage. The evolution of the normalized integrated absorbance A(ϕ)/A0 of the internal reference 1410 cm-1 band as a function of the fluence ϕ presents a complex behavior characterized by a two-exponential decay associated to low and high fluence range. The analysis reveals clearly that the A(ϕ)/A0 of the characteristic benzene ring 1577 cm-1 band remains steady till fluence around 3 × 1014 He+ cm-2 and then decreases smoothly as fluence increases. The band appearing at 1610 cm-1, assigned to mono substituted benzene, presents an integrated absorbance A(ϕ) which rises progressively and levels off beyond a critical fluence around 4 × 1014 He+ cm-2. The cross section of the creation of the monosubstituted benzene lies between 3 × 10-15 and 6 × 10-15 cm2 for (dE/dx)e = 158 and 264 keV/μm, respectively. Drastic loss of crystallinity is induced by the MeV He+ ion irradiation in the polymer. The amorphization is monitored by the evolution of the specific bands of the trans and gauche ethylene glycol residue conformations. A sudden drop in the integrated absorbance of the 1340 cm-1 band which characterizes the trans conformation is observed at fluence around 2 × 1014 He+ cm-2. On the other hand, a

  1. Observational Search for >10 MeV Electrons in the Inner Magnetosphere Using the Van Allen Probes Relativistic Proton Spectrometer

    NASA Astrophysics Data System (ADS)

    Mazur, J. E.; Looper, M. D.; O'Brien, T. P., III; Blake, J. B.

    2015-12-01

    Any detection of ultra-relativistic electrons (>10 MeV) trapped in the inner magnetosphere is potentially a sensitive indicator of a unique particle acceleration process or of a unique particle source. The 24 March 1991 shock injection of >15 MeV electrons is a classic example of the former, while the latter includes measurements in low Earth orbit of >100 MeV electrons and positrons from cosmic ray interactions with the atmosphere. In this paper we use new instrumentation on the Van Allen Probes to survey the inner magnetosphere for signatures of ultra-relativistic electrons. The Relativistic Proton Spectrometer, designed primarily for spectroscopy of 60 to 2000 MeV protons in the inner belt, nonetheless is capable of detecting minimum-ionizing electrons in a silicon detector stack. More critical to this survey is the instrument's Cherenkov radiator subsystem whose response to incident electrons ranges from a threshold near 10 MeV and reaches light saturation above 50 MeV. Together with the silicon detector system we are able to explore an energy range that has not been routinely studied in the context of the Earth's magnetosphere. We will report on quiet-time and storm-time signatures in regions of the inner magnetosphere that heretofore have not been explored with an orbit like that of Van Allen Probes. We will also quantitatively compare our electron energy spectra, or flux limits, with other measurements from Van Allen Probes and prior glimpses of high-energy electrons from low Earth orbit.

  2. Development of a Quasi-monoenergetic 6 MeV Gamma Facility at NASA Goddard Space Flight Center

    NASA Technical Reports Server (NTRS)

    Nowicki, Suzanne F.; Hunter, Stanley D.; Parsons, Ann M.

    2012-01-01

    The 6 MeV Gamma Facility has been developed at NASA Goddard Space Flight Center (GSFC) to allow in-house characterization and testing of a wide range of gamma-ray instruments such as pixelated CdZnTe detectors for planetary science and Compton and pair-production imaging telescopes for astrophysics. The 6 MeV Gamma Facility utilizes a circulating flow of water irradiated by 14 MeV neutrons to produce gamma rays via neutron capture on oxygen (O-16(n,p)N-16 yields O-16* yields O-16 + gamma). The facility provides a low cost, in-house source of 2.742, 6.129 and 7.117 MeV gamma rays, near the lower energy range of most accelerators and well above the 2.614 MeV line from the Th-228 decay chain, the highest energy gamma ray available from a natural radionuclide. The 7.13 s half-life of the N-16 decay allows the water to be irradiated on one side of a large granite block and pumped to the opposite side to decay. Separating the irradiation and decay regions allows for shielding material, the granite block, to be placed between them, thus reducing the low-energy gamma-ray continuum. Comparison between high purity germanium (HPGe) spectra from the facility and a manufactured source, Pu-238/C-13, shows that the low-energy continuum from the facility is reduced by a factor approx. 30 and the gamma-ray rate is approx.100 times higher at 6.129 MeV.

  3. Kinematically incomplete breakup reaction /sup 1/H(vector d,p)pn at 16 MeV

    SciTech Connect

    Ohlsen, G.G.; Correll, F.D.; Brown, R.E.; Jarmie, N.; Hardekopf, R.A.

    1980-12-01

    Angular distributions of the differential cross section sigma(E*,theta/sub 1//sup l/) and of the vector and tensor analyzing powers A/sub y/(E*,theta/sub 1//sup l/), A/sub xz/(E*,theta/sub 1//sup l/), A/sub xx/(E*,theta/sub 1//sup l/), A/sub yy/(E*,theta/sub 1//sup l/) for the 3-nucleon breakup reaction /sup 1/H(vector d,p)pn were measured for a deuteron bombarding energy of 16.0 MeV. The data are reported as functions of the excitation energy E* in the pn system and of the laboratory angle theta/sub 1//sup l/. Laboratory angles between 15 and 42.5/sup 0/ were studied. The excitation energy range varies from 0 to 2.6 MeV at 15/sup 0/ to 0 to 0.2 MeV at 42.5/sup 0/. An excitation energy range (bin) of 0.2 MeV, which corresponds to laboratory energy bins from 0.3 to 0.4 MeV, was used to partition the proton continua. The experimental laboratory energy resolution is about 0.15 MeV. Large effects are seen in the tensor analyzing powers, particularly in A/sub xz/, at the lowest excitation energies. Except for A/sub yy/, there is no similarity of the observed analyzing powers to the corresponding elastic-scattering analyzing powers. Some data for A/sub xz/(E*,theta/sub 1//sup l/) at other energies are also presented. 11 figures, 6 tables.

  4. Design study of a 9 MeV compact cyclotron system for PET

    NASA Astrophysics Data System (ADS)

    Lee, Byeong-No; Shin, Seung-Wook; Song, Hoseung; Kim, Hyun-Wook; Chai, Jong-Seo

    2013-06-01

    A cyclotron is an accelerator which can be applied to both cancer diagnosis and treatment. Among commercially sold cyclotrons, the major energy is used for positron emission tomography (PET) ranges from 10 to 20 MeV. In this research, 9 MeV compact cyclotron for PET was designed. The research was conducted on the response cross section and the yield for the energy distribution to decide the design features. Also, it was determined the specifications on the basis of the fluoro-deoxy-glucose (FDG) maximum dose. The machine, which has a 20 uA beam current, is designed to be installed in small-to-medium-sized hospitals in local cities because of its relatively light weight (6 tons). This compact cyclotron, which provides 9-MeV proton beams, is composed of a azimuthally varying field (AVF) electromagnet, 83-MHz RF systems with a 20 kW amplifier, a panning ion gauge (PIG) type ion-source for negative hydrogen, and a double-stage high-vacuum system. The basic model design was done by using 3-D CAD program, CATIA and all the field calculations were performed using commercial electromagnetic field analysis code, OPERA-3D TOSCA. From this research, we expect a time reduction for FDG production, a decrease of radioactive exposure for workers, and an equipment cost reduction.

  5. 1 MeV, 10 kW DC electron accelerator for industrial applications

    NASA Astrophysics Data System (ADS)

    Nayak, B.; Acharya, S.; Bhattacharjee, D.; Bakhtsingh, R. I.; Rajan, R.; Sharma, D. K.; Dewangan, S.; Sharma, V.; Patel, R.; Tiwari, R.; Benarjee, S.; Srivastava, S. K.

    2016-03-01

    Several modern applications of radiation processing like medical sterilization, rubber vulcanization, polymerization, cross-linking and pollution control from thermal power stations etc. require D.C. electron accelerators of energy ranging from a few hundred keVs to few MeVs and power from a few kilowatts to hundreds of kilowatts. To match these requirements, a 3 MeV, 30 kW DC electron linac has been developed at BARC, Mumbai and current operational experience of 1 MeV, 10 kW beam power will be described in this paper. The LINAC composed mainly of Electron Gun, Accelerating Tubes, Magnets, High Voltage source and provides 10 kW beam power at the Ti beam window stably after the scanning section. The control of the LINAC is fully automated. Here Beam Optics study is carried out to reach the preferential parameters of Accelerating as well as optical elements. Beam trials have been conducted to find out the suitable operation parameters of the system.

  6. The 2-MEV model: Constancy of adolescent environmental values within an 8-year time frame

    NASA Astrophysics Data System (ADS)

    Bogner, F. X.; Johnson, B.; Buxner, S.; Felix, L.

    2015-08-01

    The 2-MEV model is a widely used tool to monitor children's environmental perception by scoring individual values. Although the scale's validity has been confirmed repeatedly and independently as well as the scale is in usage within more than two dozen language units all over the world, longitudinal properties still need clarification. The purpose of the present study therefore was to validate the 2-MEV scale based on a large data basis of 10,676 children collected over an eight-year period. Cohorts of three different US states contributed to the sample by responding to a paper-and-pencil questionnaire within their pre-test initiatives in the context of field center programs. Since we used only the pre-program 2-MEV scale results (which is before participation in education programs), the data were clearly unspoiled by any follow-up interventions. The purpose of analysis was fourfold: First, to test and confirm the hypothesized factorized structure for the large data set and for the subsample of each of the three states. Second, to analyze the scoring pattern across the eight years' time range for both preservation and utilitarian preferences. Third, to investigate any age effects in the extracted factors. Finally, to extract suitable recommendations for educational implementation efforts.

  7. New COMPTEL results on pulsar studies at MeV energies

    NASA Technical Reports Server (NTRS)

    Hermsen, W.; Kuiper, L.; Schoenfelder, V.; Strong, A. W.; Bennett, K.; Much, R.; McConnell, M.; Ryan, J.; Carraminana, A.

    1997-01-01

    The Compton telescope (COMPTEL) onboard the Compton Gamma Ray Observatory (CGRO) detected the pulsar PSR B1951-32 at MeV energies, and found indications of a signal from PSR B0656+14. In the combined spectra from COMPTEL and the energetic gamma ray experiment telescope (EGRET) onboard CGRO, it can be seen that the maximum luminosities of these objects are reached in the COMPTEL energy range. These spectra can be compared with those from four other pulsars observed in MeV energies with COMPTEL. The spectral properties of five of the six pulsars, Vela, PSR B1509-58, PSR B1951-32 and PSR B0656+14, require breaks and bends at MeV energies. The sixth pulsar, the Crab pulsar, approximately follows a power law flux relation from keV to GeV energies. It is concluded that this spectral behavior may play a role in the discrimination between current gamma ray emission models.

  8. 10MeV 25KW industrial electron LINAC

    NASA Astrophysics Data System (ADS)

    Kamino, Y.

    1998-06-01

    A 10MeV 25KW plus class electron LINAC was developed for sterilisation of medical devices. The LINAC composed of a standing wave type single cavity prebuncher and a 2m electro-plated travelling wave guide uses a 5MW 2856MHz pulse klystron as an RF source and provides 25KW beam power at the Ti alloy beam window stably after the energy analysing magnet with 10MeV plus-minus 1 MeV energy slit. The practical maximum beam power reached 29 KW and this demonstrated the LINAC as one of the most powerful S-band electron LINACs in the world. The control of the LINAC is fully automated and the "One-Button Operation" is realised, which is valuable for easy operation as a plant system. 2 systems have been delivered and are being operated stably.

  9. Defects and diffusion in MeV implanted silicon

    SciTech Connect

    Venezia, V. C.; Haynes, T. E.; Agarwal, Aditya; Gossmann, H.-J.; Pelaz, L.; Jacobson, D. C.; Eaglesham, D. J.; Duggan, J. L.

    1999-06-10

    In this work we demonstrate that the defects that are created by 2-MeV Si ions can interact with dopant atoms both during implantation and during post-implant annealing. We show that the interstitials and vacancies created during MeV Si implantation result in a radiation enhanced diffusion of B and Sb markers, respectively, when the temperature of implantation is above the threshold temperature for formation of mobile dopant complexes. With the use of these dopant markers we also demonstrate that a vacancy-rich near surface region results during post-implant annealing of MeV implanted silicon. The depth distribution and the thermal evolution of clustered vacancies was measured by a Au labeling technique.

  10. Photon detector for MEGA. [53 MeV

    SciTech Connect

    Gagliardi, C.A.; Tribble, R.E.

    1992-01-01

    The MEGA photon detector is designed to observe the 52.83-MeV photon produced in a [mu] [yields] e[gamma] decay with an energy resolution of 1.25 MeV, a position resolution of 2 [times] 5 mm[sup 2], a directional resolution of 10[degree], a time resolution of 500 ps, and an efficiency of about 5.4%. It will consist of three independent concentric cylindrical pair spectrometers mounted within a 1.5 T magnetic field produced by a superconducting solenoid magnet. Each pair spectrometer includes two thin Pb foils to convert photons into e[sup +]e[sup [minus

  11. Earth albedo neutrons from 10 to 100 MeV.

    NASA Technical Reports Server (NTRS)

    Preszler, A. M.; Simnett, G. M.; White, R. S.

    1972-01-01

    We report the measurement of the energy and angular distributions of earth albedo neutrons from 10 to 100 MeV at 40 deg N geomagnetic latitude from a balloon at 120,000 ft, below 4.65 g/sq cm. The albedo-neutron omnidirectional energy distribution is flat to 50 MeV, then decreases with energy. The absolute neutron energy distribution is of the correct strength and shape for the albedo neutrons to be the source of the protons trapped in earth's inner radiation belt.

  12. Large momentum transfer neutron pickup with the (. pi. /sup +/,p) and (p,d) reactions. [90 and 180 MeV, 800 MeV

    SciTech Connect

    Smith, G.R.

    1980-01-01

    The (p,d) reaction was studied for the first time at 800 MeV on seven targets ranging from /sup 7/Li to /sup 40/Ca. The experimental resolution (approx. 400 keV) attained was sufficient to observe many discrete levels in each of the residual nuclei. A modified version of the one-nucleon model successfully describes the magnitude and angular dependence of almost all of the transitions observed. A specific counter example to the two-nucleon model of the reaction mechanism is suggested. The calculations are also sensitive to the neutron single-particle wave function, in accordance with the expectation that the high-momentum components of this wave function are probed at higher bombarding energies. States that have never been seen before were strongly populated in the high excitation region (up to 25 MeV) of some of the residual nuclei. The relative intensities of the other levels observed suggest that coupled-channels mechanisms play an important role for some of these states. Explicit calculations were performed to confirm this for several examples. The first high-resolution measurements of the (..pi../sup +/,p) reaction were also performed on /sup 6/Li, /sup 7/Li, /sup 12/C, and /sup 13/C at pion bombarding energies on and off the pion-nucleon resonance. Calculations employing a one-nucleon model of the reaction mechanism similar to the model successfully used for the (p,d) reaction are unable to account for transitions in the (..pi../sup +/,p) reaction. It is, however, unclear whether this failure is due to a fundamental inadequacy of the model or improper treatment of details in the calculations. A striking similarity was observed in the spectra of the (..pi../sup +/,p) and 800-MeV (p,d) reactions on the same target; this result implies a similar mechanism for the two reactions. 120 references, 97 figures, 15 tables.

  13. Measurements of the response functions of a large size NE213 organic liquid scintillator for neutrons up to 800 MeV.

    PubMed

    Taniguchi, S; Moriya, T; Takada, M; Hatanaka, K; Wakasa, T; Saito, T

    2005-01-01

    The response functions of 25.4 cm (length) x 25.4 cm (diameter) NE213 organic liquid scintillator have been measured for neutrons in the energy range from 20 to 800 MeV at the Heavy-Ion Medical Accelerator in Chiba (HIMAC) and at the Research Center for Nuclear Physics (RCNP) of Osaka University. At HIMAC, white (continuous) energy spectrum neutrons were produced by the 400 MeV per nucleon carbon ion bombardment on a thick graphite target, whose energy spectrum has already been measured by Kurosawa et al., [Nucl. Sci. Eng. 132, 30 (1999)] and the response functions of the time-of-flight-gated monoenergetic neutrons in a wide energy range from 20 to 800 MeV were simultaneously measured. At RCNP, the quasi-monoenergetic neutrons were produced via 7Li(p,n)7Be reaction by 250 MeV proton beam bombardment on a thin 7Li target, and the TOF-gated 245 MeV peak neutrons were measured. The absolute peak neutron yield was obtained by the measurement of 478 keV gamma rays from the 7Be nuclei produced in a Li target. The measured results show that the response functions for monoenergetic neutrons < 250 MeV have a recoil proton plateau and an edge around the maximum light output, which increases with increasing incident neutron energy, on the other hand > 250 MeV, the plateau and the edge become unclear because the proton range becomes longer than the detector size and the escaping protons increase. It can be found that the efficiency of the 24.5 cm (diameter) x 25.4 cm (length) NE213 for the 250 MeV neutrons is -10 times larger than the 12.7 cm (length) x 12.7 cm (diameter) NE213, which is widely used as a neutron spectrometer. PMID:16604622

  14. Time-dependent 2.2-MeV and 0.5-MeV lines from solar flares

    NASA Technical Reports Server (NTRS)

    Wang, H. T.; Ramaty, R.

    1975-01-01

    The time dependences of the 2.2- and 0.51-MeV gamma-ray lines from solar flares are calculated, and the results are compared with observations of the 1972 August 4 and 7 flares. The time lag between the nuclear reactions and the formation of these two lines is caused by capture of the neutrons and subsequent deceleration of the positrons and decay of the radioactive nuclei. Our main results are that the calculation is consistent with the observed rise of the 2.2-MeV line on August 4, and it does not require different time dependences for the accelerated protons and high-energy electrons in the flare region. The above lags can explain the delayed gamma-ray emission observed on August 7. Positrons of energies greater than about 10 MeV could be detected in interplanetary space following large solar flares.

  15. Development of mass spectrometry by high energy focused heavy ion beam: MeV SIMS with 8 MeV Cl7+ beam

    NASA Astrophysics Data System (ADS)

    Jeromel, Luka; Siketić, Zdravko; Ogrinc Potočnik, Nina; Vavpetič, Primož; Rupnik, Zdravko; Bučar, Klemen; Pelicon, Primož

    2014-08-01

    Particle induced X-ray emission (PIXE) at microprobe of Jožef Stefan Institute is used to measure two-dimensional quantitative elemental maps of biological tissue. To improve chemical and biological understanding of the processes in vivo, supplementary information about chemical bonding and/or molecular distributions could be obtained by heavy-ion induced molecular desorption and a corresponding mass spectroscopy with Time-Of-Flight (TOF) mass spectrometer. As the method combines the use of heavy focused ions in MeV energy range and TOF Secondary Ion Mass Spectrometry, it is denoted as MeV SIMS. At Jožef Stefan Institute, we constructed a linear TOF spectrometer and mount it to our multipurpose nuclear microprobe. A beam of 8 MeV 35Cl7+ could be focused to a diameter of better than 3 μm × 3 μm and pulsed by electrostatic deflection at the high-energy side of accelerator. TOF mass spectrometer incorporates an 1 m long drift tube and a double stack microchannel plate (MCP) as a stop detector positioned at the end of the drift path. Secondary ions are focused at MCP using electrostatic cylindrical einzel lens. Time of flight spectra are currently acquired with a single-hit time-to-digital converter. Pulsed ion beam produces a shower of secondary ions that are ejected from positively biased target and accelerated towards MCP. We start our time measurement simultaneously with the start of the beam pulse. Signal of the first ion hitting MCP is used to stop the time measurement. Standard pulses proportional to the time of flight are produced with time to analog converter (TAC) and fed into analog-to-digital converter to obtain a time histogram. To enable efficient detection of desorbed fragments with higher molecular masses, which are of particular interest, we recently implemented a state-of art Field Programmable Gate Array (FPGA)-based multi-hit TOF acquisition. To test the system we used focused 8 MeV 35Cl7+ ion beam with pulse length of 180 ns. Mass resolution

  16. 207,208Pb(n,xnγ) reactions for neutron energies from 3 to 200 MeV

    NASA Astrophysics Data System (ADS)

    Vonach, H.; Pavlik, A.; Chadwick, M. B.; Haight, R. C.; Nelson, R. O.; Wender, S. A.; Young, P. G.

    1994-10-01

    High-resolution γ-ray spectra from the interaction of neutrons in the energy range from 3 to 200 MeV with 207,208Pb were measured with the white neutron source at the weapons neutron research (WNR) facility at Los Alamos National Laboratory. From these data, excitation functions for prominent γ transitions in 200,202,204,206,207,208Pb were derived from threshold to 200 MeV incident neutron energy. These γ-production cross sections reflect the excitation cross sections for the respective residual nuclei. The results are compared with the predictions of nuclear reaction calculations based on the exciton model for precompound emission, the Hauser-Feshbach theory for compound nucleus decay, and coupled channels calculations to account for direct excitation of collective levels. Good agreement was obtained over the entire energy range covered in the experiment with reasonable model parameters. The results of this work clearly demonstrate that multiple preequilibrium emission has to be taken into account above about 40 MeV, and that the level density model of Ignatyuk, which accounts for the gradual disappearance of shell effects with increasing excitation energy, should be used instead of the Gilbert-Cameron and backshifted Fermi-gas models if excitation energies exceed about 30 MeV. No indication for a reduction of the nuclear moment of inertia below the rigid body value was found.

  17. The 400 MeV Linac Upgrade at Fermilab

    SciTech Connect

    Noble, R.J.

    1992-12-01

    The Fermilab Linac Upgrade in planned to increase the energy of the H{sup {minus}} linac from 200 to 400 MeV. This is intended to reduce the incoherent space-charge tuneshift at injection into the 8 GeV Booster which limit either the brightness or the total intensity of the beam. The Linac Upgrade will be achieved by replacing the last four 201.25 MHs drift-tube linac (DTL) tanks which accelerate the beam from 116 to 200 MeV, with seven 805 MRs side-coupled cavity modules operating at an average axial field of about 7.5 MV/meter. This will allow acceleration to 400 MeV in the existing Linac enclosure. Each accelerator module will be driven with a 12 MW klystron-based rf power supply. Three of seven accelerator modules have been fabricated, power tested and installed in their temporary location adjacent to the existing DTL. All seven RF Modulators have been completed and klystron installation has begun. Waveguide runs have completed from the power supply gallery to the accelerator modules. The new linac will be powered in the temporary position without beam in order to verify overall system reliability until the laboratory operating schedule permits final conversion to 400 MeV operation.

  18. 150 MeV proton medical cyclotron design study.

    PubMed

    Burleigh, R J; Clark, D J; Flood, W S

    1975-01-01

    A brief design study has been done for a 150 MeV proton sector cyclotron. The object was to minimize cost but maintain good reliability and easy maintenance. The use of the proton beam would be for therapy, radiography and isotope production.

  19. Analysis of 33 MeV Nitrogen irradiated UHMWPE

    SciTech Connect

    Grosso, Mariela del; Chappa, Veronica; Garcia Bermudez, Gerardo

    2007-10-26

    In this work, we irradiated UHMWPE with 33 MeV Nitrogen ions, at several fluences, to generate surface modifications without affecting the bulk properties. These modifications were quantified by means of wear resistance tests and Fourier transform infrared spectroscopy (FTIR) measurements. Experimental results show an optimum ion fluence value that maximizes UHMWPE wear resistance.

  20. History of the ZGS 500 MeV booster.

    SciTech Connect

    Simpson, J.; Martin; R.; Kustom, R.

    2006-05-09

    The history of the design and construction of the Argonne 500 MeV booster proton synchrotron from 1969 to 1982 is described. This accelerator has since been in steady use for the past 25 years to power the Argonne Intense Pulsed Neutron Source (IPNS).

  1. The Gent University 15 MeV high-current linear electron accelerator facility

    NASA Astrophysics Data System (ADS)

    Mondelaers, W.; Van Laere, K.; Goedefroot, A.; Van den Bossche, K.

    1996-01-01

    The Gent University 15 MeV 20kW linear electron accelerator facility was initially designed for fundamental nuclear physics research. During the last years a large effort has been devoted to the expansion of the range of machine applications in view of a new extensive experimental programme in the fields of atomic and solid-state physics, biomaterials research, polymer chemistry, space research, food technology, high-dose dosimetry and radiation therapy. The accelerator facility in its present configuration, the peripheral equipment and the experimental programme are described with emphasis on the original features.

  2. Regrowth-related defect formation and evolution in 1 MeV amorphized (001) Ge

    SciTech Connect

    Hickey, D. P.; Bryan, Z. L.; Jones, K. S.; Elliman, R. G.; Haller, E. E.

    2007-03-26

    Ge implanted with 1 MeV Si{sup +} at a dose of 1x10{sup 15} cm{sup -2} creates a buried amorphous layer that, upon regrowth, exhibits several forms of defects-end-of-range (EOR), regrowth-related, and clamshell defects. Unlike Si, no planar (311) defects are observed. The minimal EOR defects are small dotlike defects and are very unstable, dissolving between 450 and 550 deg. C. This is in contrast to Si, where the EOR defects are very stable. The amorphous layer results in both regrowth-related defects and clamshell defects, which were more stable than the EOR damage.

  3. 6 MeV heavy ion beam probe on the Large Helical Device

    SciTech Connect

    Ido, T.; Shimizu, A.; Nishiura, M.; Nishizawa, A.; Katoh, S.; Tsukada, K.; Yokota, M.; Ogawa, H.; Inoue, T.; Hamada, Y.; Crowley, T. P.

    2006-10-15

    A heavy ion beam probe (HIBP) has been installed on the Large Helical Device (LHD). A MeV-range beam is required for the LHD-HIBP. The probing beam is accelerated up to 6 MeV by use of a tandem accelerator. A new energy analyzer with tandem electrodes has also been developed to analyze such a high energy beam. As a result, a secondary beam can be detected and its energy successfully analyzed. It is verified, in principle, that the potential profile can be measured using the HIBP.

  4. MeV Mono-Energetic Gamma Ray Compton Scattering Source R&D

    NASA Astrophysics Data System (ADS)

    Hartemann, Fred; Albert, Felicie; Anderson, Scott; Chu, Sam; Cross, Rick; Ebbers, Chris; Gibson, David; Messerly, Mike; Semenov, Vlad; Shverdin, Miro; Siders, Craig; McNabb, Dennis; Barty, Chris; Vlieks, Arnold; Tantawi, Sami

    2009-11-01

    A precision, tunable gamma-ray source driven by a compact, high-gradient X-band linac is currently under development at LLNL. High-brightness, relativistic electron bunches produced by the linac interact with a Joule-class, 10 ps laser pulse to generate tunable γ-rays in the 0.5-2.5 MeV photon energy range via Compton scattering. The source will be used to excite nuclear resonance fluorescence lines in various isotopes; applications include homeland security, stockpile science and surveillance, nuclear fuel assay, and waste imaging and assay. The source design, key parameters, and current status are presented.

  5. Neutron-proton spin-correlation parameter A sub z z at 68 MeV

    SciTech Connect

    Hammans, M.; Brogli-Gysin, C.; Burzynski, S.; Campbell, J.; Haffter, P.; Henneck, R.; Lorenzon, W.; Pickar, M.A.; Sick, I. ); Konter, J.A.; Mango, S.; van den Brandt, B. )

    1991-05-06

    We report a first measurement of the spin-correlation parameter {ital A}{sub {ital z}{ital z}} in neutron-proton scattering at 67.5 MeV. The results, obtained in the angular range 105{degree}{le}{theta}{sub c.m.}{le}170{degree} with typical accuracies of 0.008, are highly sensitive to the {sup 3}{ital S}{sub 1}-{sup 3}{ital D}{sub 1} mixing parameter {epsilon}{sub 1}. A phase-shift analysis based on the current world data yields a value of {epsilon}{sub 1} significantly higher than predicted by modern potential models.

  6. An analysis of 100 MeV F 8+ ion and 50 MeV Li 3+ ion irradiation effects on silicon NPN rf power transistors

    NASA Astrophysics Data System (ADS)

    Pushpa, N.; Praveen, K. C.; Gnana Prakash, A. P.; Prabhakara Rao, Y. P.; Tripati, Ambuj; Revannasiddaiah, D.

    2010-08-01

    The dc characteristics exhibited by NPN power transistors are studied systematically before and after irradiation by 100 MeV F 8+ ions and 50 MeV Li 3+ ions in the dose range of 100 krad to 100 Mrad. The transistor parameters such as excess base current (Δ IB= IBpost- IBpre), dc current gain ( hFE), transconductance ( gm), and collector-saturation current ( ICsat) were studied before and after irradiation. The damage factors ( k) for hFE were calculated for ion irradiated transistors using Messenger-Spratt relation. The base current ( IB) was found to increase significantly after ion irradiation and this in turn decreases the hFE of the transistors. The gm decreases significantly after ion irradiation. Moreover, the output characteristics of irradiated devices also show that the collector current ( IC) in the saturation region ( ICsat) decrease with increase in ion dose. The observed change in these characteristics may be due to the ion induced generation-recombination (G-R) centers in emitter-base (E-B) spacer oxide and the ion induced point defects and their complexes in the transistor structure.

  7. The Spectrum of Isotropic Diffuse Gamma-Ray Emission Between 100 Mev and 820 Gev

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Ajello, M.; Albert, A.; Atwood, W. B.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Brandt, T. J.; Hays, E.; Perkins, J. S.

    2014-01-01

    The gamma-ray sky can be decomposed into individually detected sources, diffuse emission attributed to the interactions of Galactic cosmic rays with gas and radiation fields, and a residual all-sky emission component commonly called the isotropic diffuse gamma-ray background (IGRB). The IGRB comprises all extragalactic emissions too faint or too diffuse to be resolved in a given survey, as well as any residual Galactic foregrounds that are approximately isotropic. The first IGRB measurement with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi) used 10 months of sky-survey data and considered an energy range between 200 MeV and 100 GeV. Improvements in event selection and characterization of cosmic-ray backgrounds, better understanding of the diffuse Galactic emission, and a longer data accumulation of 50 months, allow for a refinement and extension of the IGRB measurement with the LAT, now covering the energy range from 100 MeV to 820 GeV. The IGRB spectrum shows a significant high-energy cutoff feature, and can be well described over nearly four decades in energy by a power law with exponential cutoff having a spectral index of 2.32 plus or minus 0.02 and a break energy of (279 plus or minus 52) GeV using our baseline diffuse Galactic emission model. The total intensity attributed to the IGRB is (7.2 plus or minus 0.6) x 10(exp -6) cm(exp -2) s(exp -1) sr(exp -1) above 100 MeV, with an additional +15%/-30% systematic uncertainty due to the Galactic diffuse foregrounds.

  8. Damage formation during 1.0 MeV Si self-implantation at low temperatures

    SciTech Connect

    Huang, M.B.; Mitchell, I.V.

    1999-04-01

    The effect of substrate temperature and ion flux on lattice damage in silicon induced by 1.0 MeV Si ion implantation has been investigated using Rutherford backscattering channeling (RBSC) and Raman spectroscopy. Over the temperature range of 77--323K, the temperature dependence of near-surface damage is found to be different from that of end-of-range damage. This may suggest that different mechanisms for damage growth are dominant along the ion path. The flux effect on damage accumulation varies with substrate temperatures. Around liquid nitrogen temperature (77K), the near-surface damage decreases with increasing flux, contrary to the case around room temperature (300K). In the temperature range of {approximately}120--250K, damage is almost independent of implant flux. Possible causes of the observed phenomena are discussed.

  9. Measurement and Analysis of Gamma-Rays Emitted From Spent Nuclear Fuel Above 3 MeV

    SciTech Connect

    Rodriguez, Douglas C.; Anderson, Elaina R.; Anderson, Kevin K.; Campbell, Luke W.; Fast, James E.; Jarman, Kenneth D.; Kulisek, Jonathan A.; Orton, Christopher R.; Runkle, Robert C.; Stave, Sean C.

    2013-12-01

    The gamma-ray spectrum of spent nuclear fuel in the 3- to 6-MeV energy range is important for active interrogation since emitted gamma rays emitted from nuclear decay are not expected to interfere with measurements in this energy region. There is, unfortunately, a dearth of empirical measurements from spent nuclear fuel in this region. This work is an initial attempt to partially ll this gap by presenting an analysis of gamma-ray spectra collected from a set of spent nuclear fuel sources using a high-purity germanium detector array. This multi-crystal array possesses a large collection volume, providing high energy resolution up to 16 MeV. The results of these measurements establish the continuum count-rate in the energy region between 3- and 6-MeV. Also assessed is the potential for peaks from passive emissions to interfere with peak measurements resulting from active interrogation delayed emissions. As one of the first documented empirical measurements of passive emissions from spent fuel for energies above 3 MeV, this work provides a foundation for active interrogation model validation and detector development.

  10. Measurement and analysis of gamma-rays emitted from spent nuclear fuel above 3 MeV.

    PubMed

    Rodriguez, Douglas C; Anderson, Elaina; Anderson, Kevin K; Campbell, Luke W; Fast, James E; Jarman, Kenneth; Kulisek, Jonathan; Orton, Christopher R; Runkle, Robert C; Stave, Sean

    2013-12-01

    The gamma-ray spectrum of spent nuclear fuel in the 3-6 MeV energy range is important for active interrogation since gamma rays emitted from nuclear decay are not expected to interfere with measurements in this energy region. There is, unfortunately, a dearth of empirical measurements from spent nuclear fuel in this region. This work is an initial attempt to partially fill this gap by presenting an analysis of gamma-ray spectra collected from a set of spent nuclear fuel sources using a high-purity germanium detector array. This multi-crystal array possesses a large collection volume, providing high energy resolution up to 16 MeV. The results of these measurements establish the continuum count-rate in the energy region between 3 and 6 MeV. Also assessed is the potential for peaks from passive emissions to interfere with peak measurements resulting from active interrogation delayed emissions. As one of the first documented empirical measurements of passive emissions from spent fuel for energies above 3 MeV, this work provides a foundation for active interrogation model validation and detector development. PMID:24035928

  11. Measurement of 14 MeV neutrons at TFTR with Si-diode detectors

    SciTech Connect

    Ruskov, E.; Heidbrink, W.W.; Duong, H.H.; Roquemore, A.L.; Strachan, J.D. )

    1995-01-01

    A detector system based on partially depleted silicon surface barrier detectors and fast front-end electronics has been built and cross calibrated to a set of absolutely calibrated [sup 4]He recoil detectors. The cross-calibration factor for the channel with the widest dynamic range is 2.5[times]10[sup [minus]13] counts per 14 MeV source neutron. These data agree well with the independent neutron activation data. The new detector system covers a large dynamic range (corresponding to 10[sup 13]--10[sup 18] neutrons/s). The response is linear, except at the highest count rates where the detector dead time ([similar to]200 ns) causes departure from linearity. The noise discrimination against 2.5 MeV neutrons and [gamma] pileup is excellent. Measurements of D-T neutrons from a tritium gas puff experiment as well as from a high-power D-T discharge in the TFTR tokamak are presented.

  12. Tunable nanometer electrode gaps by MeV ion irradiation

    PubMed Central

    Cheang-Wong, J.-C.; Narumi, K.; Schürmann, G. M.; Aziz, M. J.; Golovchenko, J. A.

    2012-01-01

    We report the use of MeV ion-irradiation-induced plastic deformation of amorphous materials to fabricate electrodes with nanometer-sized gaps. Plastic deformation of the amorphous metal Pd80Si20 is induced by 4.64 MeV O2+ ion irradiation, allowing the complete closing of a sub-micrometer gap. We measure the evolving gap size in situ by monitoring the field emission current-voltage (I-V) characteristics between electrodes. The I-V behavior is consistent with Fowler-Nordheim tunneling. We show that using feedback control on this signal permits gap size fabrication with atomic-scale precision. We expect this approach to nanogap fabrication will enable the practical realization of single molecule controlled devices and sensors. PMID:22550357

  13. Magnifying lens for 800 MeV proton radiography.

    PubMed

    Merrill, F E; Campos, E; Espinoza, C; Hogan, G; Hollander, B; Lopez, J; Mariam, F G; Morley, D; Morris, C L; Murray, M; Saunders, A; Schwartz, C; Thompson, T N

    2011-10-01

    This article describes the design and performance of a magnifying magnetic-lens system designed, built, and commissioned at the Los Alamos National Laboratory (LANL) for 800 MeV flash proton radiography. The technique of flash proton radiography has been developed at LANL to study material properties under dynamic loading conditions through the analysis of time sequences of proton radiographs. The requirements of this growing experimental program have resulted in the need for improvements in spatial radiographic resolution. To meet these needs, a new magnetic lens system, consisting of four permanent magnet quadrupoles, has been developed. This new lens system was designed to reduce the second order chromatic aberrations, the dominant source of image blur in 800 MeV proton radiography, as well as magnifying the image to reduce the blur contribution from the detector and camera systems. The recently commissioned lens system performed as designed, providing nearly a factor of three improvement in radiographic resolution. PMID:22047305

  14. Magnifying lens for 800 MeV proton radiography

    NASA Astrophysics Data System (ADS)

    Merrill, F. E.; Campos, E.; Espinoza, C.; Hogan, G.; Hollander, B.; Lopez, J.; Mariam, F. G.; Morley, D.; Morris, C. L.; Murray, M.; Saunders, A.; Schwartz, C.; Thompson, T. N.

    2011-10-01

    This article describes the design and performance of a magnifying magnetic-lens system designed, built, and commissioned at the Los Alamos National Laboratory (LANL) for 800 MeV flash proton radiography. The technique of flash proton radiography has been developed at LANL to study material properties under dynamic loading conditions through the analysis of time sequences of proton radiographs. The requirements of this growing experimental program have resulted in the need for improvements in spatial radiographic resolution. To meet these needs, a new magnetic lens system, consisting of four permanent magnet quadrupoles, has been developed. This new lens system was designed to reduce the second order chromatic aberrations, the dominant source of image blur in 800 MeV proton radiography, as well as magnifying the image to reduce the blur contribution from the detector and camera systems. The recently commissioned lens system performed as designed, providing nearly a factor of three improvement in radiographic resolution.

  15. Magnifying lens for 800 MeV proton radiography

    SciTech Connect

    Merrill, F. E.; Campos, E.; Espinoza, C.; Hogan, G.; Hollander, B.; Lopez, J.; Mariam, F. G.; Morley, D.; Morris, C. L.; Murray, M.; Saunders, A.; Schwartz, C.; Thompson, T. N.

    2011-10-15

    This article describes the design and performance of a magnifying magnetic-lens system designed, built, and commissioned at the Los Alamos National Laboratory (LANL) for 800 MeV flash proton radiography. The technique of flash proton radiography has been developed at LANL to study material properties under dynamic loading conditions through the analysis of time sequences of proton radiographs. The requirements of this growing experimental program have resulted in the need for improvements in spatial radiographic resolution. To meet these needs, a new magnetic lens system, consisting of four permanent magnet quadrupoles, has been developed. This new lens system was designed to reduce the second order chromatic aberrations, the dominant source of image blur in 800 MeV proton radiography, as well as magnifying the image to reduce the blur contribution from the detector and camera systems. The recently commissioned lens system performed as designed, providing nearly a factor of three improvement in radiographic resolution.

  16. First Light: MeV Astrophysics from the Moon

    NASA Astrophysics Data System (ADS)

    Miller, Richard S.; Lawrence, David J.

    2016-06-01

    We report evidence of the first astrophysical source detected from the Moon at MeV energies. Our detection of Cygnus X-1 is a validation of a new investigative paradigm in which the lunar environment is intrinsic to the detection approach: the Lunar Occultation Technique (LOT). NASA’s Lunar Prospector mission served as a proxy for a dedicated LOT-based mission. The characteristic signature of temporal modulation, generated by repeated lunar occultations and encoded within acquired gamma-ray data (0.5-9 MeV), is consistent with an unambiguous detection of Cygnus X-1 at 5.4σ significance. Source localization and long-term monitoring capabilities of the LOT are also demonstrated. This “first light” detection verifies the basic tenets of the LOT methodology, reinforces its feasibility as an alternative astronomical detection paradigm for nuclear astrophysics investigations, and is an illustration of the fundamental benefits of the Moon as a platform for science.

  17. Anisotropies in the interplanetary intensity of solar protons with energies greater than 0.3 MeV.

    NASA Technical Reports Server (NTRS)

    Innanen, W. G.; Van Allen, J. A.

    1973-01-01

    By using Explorer 35 interplanetary observations of solar protons with energies greater than 0.3 MeV during ten selected solar events (1967-1970) the tine dependence of intensity and of the angular distribution of intensity has been studied for the first time in the sub-MeV range of energy. The respective contributions of diffusive and convective transport are resolved. Results are qualitatively similar to those of McCracken et al. (1968, 1971) in the energy range from 7.5to 45 MeV; but, as was expected, convective transport is found to be relatively more important at the lower energies. The convective component of the anisotropy vector yields values of the solar wind velocity in good agreement with directly measured values.

  18. 5 MeV Mott Polarimeter Development at Jefferson Lab

    SciTech Connect

    Price, J. S.; Sinclair, C. K.; Cardman, L. S.; Haanskneccht, J.; Mack, D. J.; Piot, P.; Assamagan, K. A.; Grames, J.

    1997-01-01

    Low energy (E{sub k}=100 keV) Mott scattering polarimeters are ill- suited to support operations foreseen for the polarized electron injector at Jefferson Lab. One solution is to measure the polarization at 5 MeV where multiple and plural scattering are unimportant and precision beam monitoring is straightforward. The higher injector beam current offsets the lower cross-sections. Recent improvements in the CEBAF injector polarimeter scattering chamber have improved signal to noise.

  19. RADIATION DAMAGE TO BSCCO-2223 FROM 50 MEV PROTONS

    SciTech Connect

    Zeller, A.F.; Ronningen, R.M.; Godeke, A.; Heilbronn, L.H.; McMahan-Norris, P.; Gupta, R.

    2007-11-27

    The use of HTS materials in high radiation environmentsrequires that the superconducting properties remain constant up to aradiation high dose. BSCCO-2223 samples from two manufacturers wereirradiated with 50 MeV protons at fluences of up to 5 x 1017 protons/cm2.The samples lost approximately 75 percent of their pre-irradiation Ic.This compares with Nb3Sn, which loses about 50 percent at the samedisplacements per atom.

  20. RADIATION DAMAGE TO BSCCO-2223 FROM 50 MEV PROTONS

    SciTech Connect

    Zeller, A.F.; Ronningen, R.M.; Godeke, Arno; Heibronn, L.H; McMahan-Norris, P.; Gupta, R.

    2007-11-01

    The use of HTS materials in high radiation environments requires that the superconducting properties remain constant up to a radiation high dose. BSCCO-2223 samples from two manufacturers were irradiated with 50 MeV protons at fluences of up to 5 x 10{sup 17} protons/cm{sup 2}. The samples lost approximately 75% of their pre-irradiation I{sub c}. This compares with Nb{sub 3}Sn, which loses about 50% at the same displacements per atom.

  1. Fission studies with 140 MeV {alpha} particles

    SciTech Connect

    Buttkewitz, A.; Duhm, H. H.; Strauss, W.; Goldenbaum, F.; Machner, H.

    2009-09-15

    Binary fission induced by 140 MeV {alpha} particles has been measured for {sup nat}Ag, {sup 139}La, {sup 165}Ho, and {sup 197}Au targets. The measured quantities are the total kinetic energies, fragment masses, and fission cross sections. The results are compared with other data and systematics. A minimum of the fission probability in the vicinity Z{sup 2}/A=24 is observed.

  2. Discovery of a 1731-MeV narrow resonance

    NASA Astrophysics Data System (ADS)

    Vladimirsky, V. V.; Grigor'ev, V. K.; Erofeev, I. A.; Erofeeva, O. N.; Zaitsev, A. P.; Katinov, Yu. V.; Lisin, V. I.; Luzin, V. N.; Nozdrachev, V. N.; Sokolovsky, V. V.; Fadeeva, E. A.; Shkurenko, Yu. P.

    2007-10-01

    Results obtained by studying a previously unknown narrow meson of mass about 1731 MeV are presented. This state was found in a system of two K S mesons. The experimental-data set subjected to the present analysis was obtained with a 6-m spectrometer of the Institute of Theoretical and Experimental Physics (ITEP, Moscow). The statistical sample of event of double K S -meson production was accumulated in π- p interactions by using a beam of 40-GeV pions from the U-70 accelerator of the Institute of High Energy Physics (IHEP, Protvino). There are 58 events at the respective maximum, its statistical significance being close to six standard deviations. The parameters of the observed meson are the following; the mass is M = 1731 ± 2.5 MeV, the width is σ = 3.2 ± 2 MeV, and the product of the production cross section and the respective branching ratio is not less than 20 nb. The fact that the observed meson is extremely narrow does not have a satisfactory theoretical explanation.

  3. Femtosecond time-resolved MeV electron diffraction

    SciTech Connect

    Zhu, Pengfei; Zhu, Y.; Hidaka, Y.; Wu, L.; Cao, J.; Berger, H.; Geck, J.; Kraus, R.; Pjerov, S.; Shen, Y.; Tobey, R. I.; Hill, J. P.; Wang, X. J.

    2015-06-02

    We report the experimental demonstration of femtosecond electron diffraction using high-brightness MeV electron beams. High-quality, single-shot electron diffraction patterns for both polycrystalline aluminum and single-crystal 1T-TaS2 are obtained utilizing a 5 fC (~3 × 104 electrons) pulse of electrons at 2.8 MeV. The high quality of the electron diffraction patterns confirms that electron beam has a normalized emittance of ~50 nm rad. The transverse and longitudinal coherence length is ~11 and ~2.5 nm, respectively. The timing jitter between the pump laser and probe electron beam was found to be ~100 fs (rms). The temporal resolution is demonstrated by observing the evolution of Bragg and superlattice peaks of 1T-TaS2 following an 800 nm optical pump and was found to be 130 fs. Lastly, our results demonstrate the advantages of MeV electrons, including large elastic differential scattering cross-section and access to high-order reflections, and the feasibility of ultimately realizing below 10 fs time-resolved electron diffraction.

  4. Femtosecond time-resolved MeV electron diffraction

    DOE PAGES

    Zhu, Pengfei; Zhu, Y.; Hidaka, Y.; Wu, L.; Cao, J.; Berger, H.; Geck, J.; Kraus, R.; Pjerov, S.; Shen, Y.; et al

    2015-06-02

    We report the experimental demonstration of femtosecond electron diffraction using high-brightness MeV electron beams. High-quality, single-shot electron diffraction patterns for both polycrystalline aluminum and single-crystal 1T-TaS2 are obtained utilizing a 5 fC (~3 × 104 electrons) pulse of electrons at 2.8 MeV. The high quality of the electron diffraction patterns confirms that electron beam has a normalized emittance of ~50 nm rad. The transverse and longitudinal coherence length is ~11 and ~2.5 nm, respectively. The timing jitter between the pump laser and probe electron beam was found to be ~100 fs (rms). The temporal resolution is demonstrated by observing themore » evolution of Bragg and superlattice peaks of 1T-TaS2 following an 800 nm optical pump and was found to be 130 fs. Lastly, our results demonstrate the advantages of MeV electrons, including large elastic differential scattering cross-section and access to high-order reflections, and the feasibility of ultimately realizing below 10 fs time-resolved electron diffraction.« less

  5. Measurement of the Z31 contribution to the stopping power using MeV protons and antiprotons: The Barkas effect

    NASA Astrophysics Data System (ADS)

    Andersen, L. H.; Hvelplund, P.; Knudsen, H.; Möller, S. P.; Pedersen, J. O. P.; Uggerhöj, E.; Elsener, K.; Morenzoni, E.

    1989-04-01

    The stopping power for antiprotons has been measured for the first time. The antiproton stopping power of silicon is found to be 3%-19% lower than for equivelocity protons over the energy range 3.01 to 0.538 MeV. The ``Z31 contribution'' to the stopping power (the Barkas effect) is deduced by comparing the stopping power for protons and antiprotons.

  6. Incident particle range dependence of radiation damage in a power bipolar junction transistor

    NASA Astrophysics Data System (ADS)

    Liu, Chao-Ming; Li, Xing-Ji; Geng, Hong-Bin; Rui, Er-Ming; Guo, Li-Xin; Yang, Jian-Qun

    2012-10-01

    The characteristic degradations in silicon NPN bipolar junction transistors (BJTs) of type 3DD155 are examined under the irradiations of 25-MeV carbon (C), 40-MeV silicon (Si), and 40-MeV chlorine (Cl) ions respectively. Different electrical parameters are measured in-situ during the exposure of heavy ions. The experimental data shows that the changes in the reciprocal of the gain variation (Δ(1/β)) of 3DD155 transistors irradiated respectively by 25-MeV C, 40-MeV Si, and 40-MeV Cl ions each present a nonlinear behaviour at a low fluence and a linear response at a high fluence. The Δ(1/β) of 3DD155 BJT irradiated by 25-MeV C ions is greatest at a given fluence, a little smaller when the device is irradiated by 40-MeV Si ions, and smallest in the case of the 40-MeV Cl ions irradiation. The measured and calculated results clearly show that the range of heavy ions in the base region of BJT affects the level of radiation damage.

  7. Large scale silver nanowires network fabricated by MeV hydrogen (H+) ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Honey, S.; Naseem, S.; Ishaq, A.; Maaza, M.; Bhatti, M. T.; Wan, D.

    2016-04-01

    A random two-dimensional large scale nano-network of silver nanowires (Ag-NWs) is fabricated by MeV hydrogen (H+) ion beam irradiation. Ag-NWs are irradiated under H+ ion beam at different ion fluences at room temperature. The Ag-NW network is fabricated by H+ ion beam-induced welding of Ag-NWs at intersecting positions. H+ ion beam induced welding is confirmed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Moreover, the structure of Ag NWs remains stable under H+ ion beam, and networks are optically transparent. Morphology also remains stable under H+ ion beam irradiation. No slicings or cuttings of Ag-NWs are observed under MeV H+ ion beam irradiation. The results exhibit that the formation of Ag-NW network proceeds through three steps: ion beam induced thermal spikes lead to the local heating of Ag-NWs, the formation of simple junctions on small scale, and the formation of a large scale network. This observation is useful for using Ag-NWs based devices in upper space where protons are abandoned in an energy range from MeV to GeV. This high-quality Ag-NW network can also be used as a transparent electrode for optoelectronics devices. Project supported by the National Research Foundation of South Africa (NRF), the French Centre National pour la Recherche Scientifique, iThemba-LABS, the UNESCO-UNISA Africa Chair in Nanosciences & Nanotechnology, the Third World Academy of Science (TWAS), Organization of Women in Science for the Developing World (OWSDW), the Abdus Salam ICTP via the Nanosciences African Network (NANOAFNET), and the Higher Education Commission (HEC) of Pakistan.

  8. Neutron-neutron quasifree scattering in nd breakup at 10 MeV

    NASA Astrophysics Data System (ADS)

    Malone, R. C.; Crowe, B.; Crowell, A. S.; Cumberbatch, L. C.; Esterline, J. H.; Fallin, B. A.; Friesen, F. Q. L.; Han, Z.; Howell, C. R.; Markoff, D.; Ticehurst, D.; Tornow, W.; Witała, H.

    2016-03-01

    The neutron-deuteron (nd) breakup reaction provides a rich environment for testing theoretical models of the neutron-neutron (nn) interaction. Current theoretical predictions based on rigorous ab-initio calculations agree well with most experimental data for this system, but there remain a few notable discrepancies. The cross section for nn quasifree (QFS) scattering is one such anomaly. Two recent experiments reported cross sections for this particular nd breakup configuration that exceed theoretical calculations by almost 20% at incident neutron energies of 26 and 25 MeV [1, 2]. The theoretical values can be brought into agreement with these results by increasing the strength of the 1S0 nn potential matrix element by roughly 10%. However, this modification of the nn effective range parameter and/or the 1S0 scattering length causes substantial charge-symmetry breaking in the nucleon-nucleon force and suggests the possibility of a weakly bound di-neutron state [3]. We are conducting new measurements of the cross section for nn QFS in nd breakup. The measurements are performed at incident neutron beam energies below 20 MeV. The neutron beam is produced via the 2H(d, n)3He reaction. The target is a deuterated plastic cylinder. Our measurements utilize time-of-flight techniques with a pulsed neutron beam and detection of the two emitted neutrons in coincidence. A description of our initial measurements at 10 MeV for a single scattering angle will be presented along with preliminary results. Also, plans for measurements at other energies with broad angular coverage will be discussed.

  9. Cross sections and analyzing powers of sup 15 N(p,n) sup 15 O at 200 MeV and 494 MeV

    SciTech Connect

    Ciskowski, D.E. )

    1989-11-01

    Differential cross sections and analyzing powers have been measured for the {sup 15}N(p,n){sup 15} O(g.s.) reaction at bombarding energies of 200 MeV and 494 MeV. The 494 MeV data were obtained at the LAMPF Neutron Time-Of-Flight Facility on an 82 m flight path with a resolution of about 2.7 MeV. The 200 MeV data were obtained at IUCF on a 76m flight path with a resolution of about 1.1 MeV. At both energies, the measured analyzing power is small, the magnitude is less than .2 for momentum transfers of less than 1 fm{sup {minus}1}. In contrast, both Relativistic and standard DWIA calculations predict a maximum of A={minus}.7 near q=0.7 fm{sup {minus}1}. 53 refs., 44 figs.

  10. 17O(n,α)14C cross section from 25 meV to approximately 1 MeV

    NASA Astrophysics Data System (ADS)

    Koehler, P. E.; Graff, S. M.

    1991-12-01

    We have measured the 17O(n,α)14C cross section from thermal energy to approximately 1 MeV. A bump in the data near 3 keV could be fitted by a state whose properties are consistent with a known subthreshold J π=1- level at Ex=8.039 MeV. The cause of the 1/v cross section near thermal energy could not be determined although the known 2+ state at 8.213 MeV was found to be too narrow to contribute much to the thermal cross section. Our data are compared to measurements made via the inverse reaction. There are many differences between the two sets of data. The astrophysical reaction rate was calculated from the measured cross section. This reaction plays a role in the nucleosynthesis of heavy elements in nonstandard big-bang models. At big-bang temperatures, the experimental rate was found to be in fair agreement with the rate estimated from the previously known properties of states of 18O in this region. Furthermore, using the available information from experiments, it was estimated that the 17O(n,α)14C rate is approximately a factor of 103-104 times larger than the 17O(n,γ)18O rate at big-bang temperatures. As a result, there may be significant cycling between 14C and 17O resulting in a reduction of heavy-element nucleosynthesis.

  11. Study of imaging plate detector sensitivity to 5-18 MeV electrons

    SciTech Connect

    Boutoux, G. Rabhi, N.; Batani, D.; Ducret, J.-E.; Binet, A.; Nègre, J.-P.; Reverdin, C.; Thfoin, I.; Jakubowska, K.

    2015-11-15

    Imaging plates (IPs) are commonly used as passive detectors in laser-plasma experiments. We calibrated at the ELSA electron beam facility (CEA DIF) the five different available types of IPs (namely, MS-SR-TR-MP-ND) to electrons from 5 to 18 MeV. In the context of diagnostic development for the PETawatt Aquitaine Laser (PETAL), we investigated the use of stacks of IP in order to increase the detection efficiency and get detection response independent from the neighboring materials such as X-ray shielding and detector supports. We also measured fading functions in the time range from a few minutes up to a few days. Finally, our results are systematically compared to GEANT4 simulations in order to provide a complete study of the IP response to electrons over the energy range relevant for PETAL experiments.

  12. Capacitance and conductance studies on silicon solar cells subjected to 8 MeV electron irradiations

    NASA Astrophysics Data System (ADS)

    Sathyanarayana Bhat, P.; Rao, Asha; Sanjeev, Ganesh; Usha, G.; Priya, G. Krishna; Sankaran, M.; Puthanveettil, Suresh E.

    2015-06-01

    The space grade silicon solar cells were irradiated with 8 MeV electrons with doses ranging from 5-100 k Gy. Capacitance and conductance measurements were carried out in order to investigate the anomalous degradation of the cells in the radiation harsh environments and the results are presented in this paper. Detailed and systematic analysis of the frequency-dependent capacitance and conductance measurements were performed to extract the information about the interface trap states. The small increase in density of interface states was observed from the conductance-frequency measurements. The reduction in carrier concentration upon electron irradiation is due to the trapping of charge carriers by the radiation induced trap centres. The Drive Level Capacitance Profiling (DLCP) technique has been applied to study the properties of defects in silicon solar cells. A small variation in responding state densities with measuring frequency was observed and the defect densities are in the range 1015 -1016 cm-3.

  13. Forward-angle neutron-proton scattering at 96 MeV

    SciTech Connect

    Johansson, C.; Blomgren, J.; Atac, A.; Bergenwall, B.; Hildebrand, A.; Klug, J.; Mermod, P.; Pomp, S.; Oesterlund, M.; Dangtip, S.; Tippawan, U.; Elmgren, K.; Jonsson, O.; Prokofiev, A.V.; Renberg, P.-U.; Nadel-Turonski, P.; Nilsson, L.; Olsson, N.

    2005-02-01

    The differential np scattering cross section has been measured at 96 MeV in the angular range {theta}{sub c.m.}=20 deg. -76 deg. Together with an earlier data set at the same energy, covering the angles {theta}{sub c.m.}=74 deg. -180 deg., a new data set has been formed in the angular range {theta}{sub c.m.}=20 deg. - 180 deg. This extended data set has been normalized to the experimental total np cross section, resulting in a renormalization of the earlier data of 0.7%, which is well within the reported normalization uncertainty for that experiment. A novel normalization technique has been investigated. The results on forward np scattering are in reasonable agreement with theory models and partial wave analyses and have been compared with data from the literature.

  14. Low-energy theorems for nucleon-nucleon scattering at Mπ=450 MeV

    NASA Astrophysics Data System (ADS)

    Baru, V.; Epelbaum, E.; Filin, A. A.

    2016-07-01

    We apply the low-energy theorems to analyze the recent lattice QCD results for the two-nucleon system at a pion mass of Mπ≃450 MeV obtained by the NPLQCD Collaboration. We find that the binding energies of the deuteron and dineutron are inconsistent with the low-energy behavior of the corresponding phase shifts within the quoted uncertainties and vice versa. Using the binding energies of the deuteron and dineutron as input, we employ the low-energy theorems to predict the phase shifts and extract the scattering length and the effective range in the S31 and S10 channels. Our results for these quantities are consistent with those obtained by the NPLQCD Collaboration from effective field theory analyses but are in conflict with their determination based on the effective-range approximation.

  15. Interaction of Superconducting YBa2Cu(sub 3-x)Zn(sub x)O(sub 7-y) with MeV Radiation

    NASA Technical Reports Server (NTRS)

    Lewis, R. A.; Robertson, G. A.

    2005-01-01

    When the high Tc superconductor Y-Ba-Cu-O is cooled with liquid nitrogen, the conduction holes form a macroscopic collective or entangled state. While collective effects have been observed with radiation energies up to 5 eV, no high-sensitivity experiments have previously been carried out to search for comparable effects with MeV radiation. Here an experiment using a pair of scintillation counters arranged to search for changes in the natural background of high energy radiation adjacent to a warm and cold Y-Ba-Cu-O superconductor is described. The experiment showed a shift toward higher pulse heights when the SC was cooled, with a 4 standard deviation excess of 9.12+/-2.28 events/ksec over the range of 0 to 18 MeV. The net difference spectrum shows a 5.5 standard deviation excess signal for the range of 3 to 6 MeV.

  16. Production of α-particle emitting 211At using 45 MeV α-beam

    NASA Astrophysics Data System (ADS)

    Kim, Gyehong; Chun, Kwonsoo; Park, Sung Ho; Kim, Byungil

    2014-06-01

    Among the α-particle emitting radionuclides, 211At is considered to be a promising radionuclide for targeted cancer therapy due to its decay properties. The range of alpha particles produced by the decay of 211At are less than 70 µm in water with a linear energy transfer between 100 and 130 keV µm-1, which are about the maximum relative biological effectiveness for heavy ions. It is important to note that at the present time, only a few of cyclotrons routinely produce 211At. The direct production method is based on the nuclear reactions 209Bi(α,2n)211At. Production of the radionuclide 211At was carried out using the MC-50 cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). To ensure high beam current, the α-beam was extracted with an initial energy of 45 MeV, which was degraded to obtain the appropriate α-beam energy. The calculations of beam energy degradation were performed utilizing the MCNPX. Alumina-baked targets were prepared by heating the bismuth metal powder onto a circular cavity in a furnace. When using an Eα, av of 29.17 MeV, the very small contribution of 210At confirms the right choice of the irradiation energy to obtain a pure production of 211At isotope.

  17. Neutron induced light-ion production from Iron and Bismuth at 175 MeV

    NASA Astrophysics Data System (ADS)

    Bevilacqua, R.; Pomp, S.; Simutkin, V.; Tippawan, U.; Andersson, P.; Blomgren, J.; Österlund, M.; Hayashi, M.; Hirayama, S.; Naito, Y.; Watanabe, Y.; Tesinsky, M.; Lecolley, F.-R.; Marie, N.; Hjalmarsson, A.; Prokofiev, A.; Kolozhvari, A.

    2010-03-01

    We have measured light-ion (p, d, t, 3He and α) production in the interaction of 175 MeV neutrons with iron and bismuth, using the MEDLEY setup. A large set of measurements at 96 MeV has been recently completed and published, and now higher energy region is under investigation. MEDLEY is a conventional spectrometer system that allows low-energy thresholds and offers measurements over a wide angular range. The system consists of eight telescopes, each of them composed of two silicon surface barrier detectors, to perform particle identification, and a CsI(Tl) scintillator to fully measure the kinetic energy of the produced light-ions. The telescopes are placed at angles from 20° to 160°, in steps of 20°. Measurements have been performed at The Svedberg Laboratory, Uppsala (Sweden), where a quasi mono-energetic neutron beam is available and well characterized. Time of flight techniques are used to select light-ion events induced by neutrons in the main peak of the source neutron spectrum. We report preliminary double differential cross sections for production of protons, deuterons and tritons in comparison with model calculations using TALYS-1.0 code.

  18. The 2.5 MeV neutron flux monitor for MAST

    NASA Astrophysics Data System (ADS)

    Cecconello, M.; Sangaroon, S.; Conroy, S.; Donato, M.; Ericsson, G.; Marini-Bettolo, C.; Ronchi, R.; Stro¨m, P.; Weiszflog, M.; Wodniak, I.; Turnyanskiy, M.; Akers, R.; Cullen, A.; Fitzgerald, I.; McArdle, G.; Pacoto, C.; Thomas-Davies, N.

    2014-07-01

    A proof-of-principle collimated Neutron flux Camera (NC) monitor for the measurement of the 2.45 MeV neutron emission from the deuterium-deuterium fusion reactions has been developed, installed and put into use at the Mega Ampere Spherical Tokamak (MAST). The NC measures the spatial and time resolved volume integrated neutron emissivity in deuterium fusion plasmas in the presence of auxiliary plasma heating along two equatorial and two diagonal lines of sight whose tangency radius can be varied between plasma discharges. This paper describes the NC design principles, their technical realization and its performances illustrated with experimental observations of different plasma scenarios. Neutron count rates in the range 0.1-1.5 MHz are routinely observed allowing time resolutions as high as 1 ms with a statistical uncertainty less than 10% and an energy threshold of 0.5 MeV. Examples of the effect of plasma instabilities on the neutron emission are presented. The good results obtained will be used for the design of the neutron flux camera monitor for MAST Upgrade.

  19. LET spectrometry of 14 MeV (D-T) neutrons using CR-39 track detectors

    NASA Astrophysics Data System (ADS)

    Sahoo, G. S.; Tripathy, S. P.; Sunil, C.; Sarkar, P. K.

    2013-04-01

    Linear energy transfer (LET) spectrum in water in the range of 12 keV/μm to 382 keV/μm due to 14 MeV (D-T) neutrons is estimated using the track size parameters in two different types of CR-39 track detectors, viz. Intercast (1.5 mm) and Pershore (0.5 mm). Another set of CR-39s (Intercast) combined with 1 mm polyethylene (PE) radiators is exposed to study the effect of enhanced recoils on the LET spectrum. The detection efficiencies for all these cases and the enhancement ratio due to PE radiator are determined. Using this LET spectrum, the microdosimetric spectra of absorbed doses and dose equivalents are estimated based on the Q-L conversion factors as given in ICRP 60. The shape of the LET spectra are found to be similar in all the cases, however, the dose equivalents obtained with the CR-39+PE radiator is about 20% more than the other detectors without PE. The ratios of dose equivalents obtained from LET spectra (HLET) and the ambient dose equivalent (H*(10)) obtained from fluence-to-dose equivalent conversion factors (ICRP 74) for 14 MeV neutrons are used to estimate the dose response of the detectors. H*(10) is also measured using a neutron rem meter, the response of which is found to be about 23% less than the actual dose.

  20. Thick photoresist outgassing during MeV implantation (mechanism & impact on production)

    SciTech Connect

    Lee, W.J.; Tokoro, N.; Cho, H.T.

    1996-12-31

    The generation of an ion beam and its impact into photoresist-masked wafers will have an adverse effect on the vacuum of an MeV ion implanter. This is particularly significant when implanting with higher energies and higher beam current through the thick photoresist. In this paper, we will present the mechanism and effects of photoresist outgassing caused by high energy ion implantation (250KeV to 3 MeV). Due to photoresist outgassing and its effects, production usable beam current on small process chamber can be significantly limited. Photoresist outgassing from various implant conditions will be discussed. Photoresist of various thicknesses up to 4.5um from several vendors and both positive and negative acting resists were compared. Both ionization (electron stripping) and neutralization (electron addition) were measured as dose shift (underdose or overdose) using TW and Rs analysis. Depending on the ion species, energy and beam current, chamber pressure rises. The pressure rise could be as high as in the E-4 torr range. If the chamber pressure is kept below 3.0E-5 torr no observable dose shift could be detected.

  1. The solar gamma ray spectrum between 4 and 8 MeV

    NASA Technical Reports Server (NTRS)

    Ramaty, R.; Kozlovsky, B.; Suri, A. N.

    1976-01-01

    The properties of nuclear gamma ray emission in the 4 to 8 MeV range were evaluated. This emission consists of broad and narrow lines resulting from nuclear reactions of energetic H, He, C and O nuclei with ambient matter. Calculations were compared with observations of the 1972, August 4 flare and show that: (1) essentially all the observed radiation in the 4 to 8 MeV region is to the superposition of broad and narrow lines of nuclear origin with almost no contribution from other mechanisms; (2) the accelerated particles in the energy region from about 10 to 100 MeV/amu have a relatively flat Energy spectrum; (3) the calculated gamma ray spectrum, obtained from an isotropic distribution of accelerated particles, fits the observed spectrum better than the spectrum derived from an anisotropic distribution for which the particles' velocity vectors point towards the photosphere; and (4) it is possible to set a stringent upper limit on the ratio of relativistic electrons to protons in flares, consistent with the small, but finite, electron-to-proton ratio in galactic cosmic rays.

  2. MeV proton flux predictions near Saturn's D ring

    NASA Astrophysics Data System (ADS)

    Kollmann, P.; Roussos, E.; Kotova, A.; Cooper, J. F.; Mitchell, D. G.; Krupp, N.; Paranicas, C.

    2015-10-01

    Radiation belts of MeV protons have been observed just outward of Saturn's main rings. During the final stages of the mission, the Cassini spacecraft will pass through the gap between the main rings and the planet. Based on how the known radiation belts of Saturn are formed, it is expected that MeV protons will be present in this gap and also bounce through the tenuous D ring right outside the gap. At least one model has suggested that the intensity of MeV protons near the planet could be much larger than in the known belts. We model this inner radiation belt using a technique developed earlier to understand Saturn's known radiation belts. We find that the inner belt is very different from the outer belts in the sense that its intensity is limited by the densities of the D ring and Saturn's upper atmosphere, not by radial diffusion and satellite absorption. The atmospheric density is relatively well constrained by EUV occultations. Based on that we predict an intensity in the gap region that is well below that of the known belts. It is more difficult to do the same for the region magnetically connected to the D ring since its density is poorly constrained. We find that the intensity in this region can be comparable to the known belts. Such intensities pose no hazard to the mission since Cassini would only experience these fluxes on timescales of minutes but might affect scientific measurements by decreasing the signal-to-contamination ratio of instruments.

  3. The 14 MeV Frascati neutron generator

    NASA Astrophysics Data System (ADS)

    Martone, M.; Angelone, M.; Pillon, M.

    1994-09-01

    The 14-MeV Frascati neutron generator (FNG) uses the T(d, n)α fusion reaction to produce 5.0 × 10 11 n/s. In FNG a beam of deuterons is accelerated up to 300 keV by means of a linear electrostatic tube and directed onto a tritiated-titanium target containing 37 × 10 10 Bq of tritium. This paper describes the FNG facility and its auxiliary apparatus as well as the neutron source calibration performed using the associated α-particle method.

  4. Stability Study of ATF 80MeV Injector Linac

    SciTech Connect

    McCormick, Douglas

    2003-06-09

    A beam stability test was carried out at ATF 80 MeV injector linac. The test was performed by taking data of each monitor in pulse to pulse base. A data acquisition system which consists of a PC and a GPIB network was used for the test. In order to analyze the data, ''Correlation Plot'' method is used which is effective to find out some source of the observed beam fluctuation. This paper describes the result of the stability measurement and the comparison between ATF injector and SLC injector.

  5. Polarization observables in deuteron photodisintegration below 360 MeV

    SciTech Connect

    Glister, J.; Ron, G.; Lee, B. W.; Gilman, R.; Sarty, A. J.; Strauch, S.; Higinbotham, D. W.; Piasetzky, E.; Allada, K.; Armstrong, W.; Arrington, J.; Arenhövel, H.; Beck, A.; Benmokhtar, F.; Berman, B. L.; Boeglin, W.; Brash, E.; Camsonne, A.; Calarco, J.; Chen, J. P.; Choi, S.; Chudakov, E.; Coman, L.; Craver, B.; Cusanno, F.; Dumas, J.; Dutta, C.; Feuerbach, R.; Freyberger, A.; Frullani, S.; Garibaldi, F.; Hansen, J. -O.; Holmstrom, T.; Hyde, C. E.; Ibrahim, H.; Ilieva, Y.; de Jager, C. W.; Jiang, X.; Jones, M. K.; Kang, Hyekoo; Kelleher, A.; Khrosinkova, E.; Kuchina, E.; Kumbartzki, G.; LeRose, J. J.; Lindgren, R.; Markowitz, P.; May-Tal Beck, S.; McCullough, E.; Meekins, D.; Meziane, M.; Meziani, Z. -E.; Michaels, R.; Moffit, B.; Norum, B. E.; Oh, Y.; Olson, M.; Paolone, M.; Paschke, K.; Perdrisat, C. F.; Potokar, M.; Pomatsalyuk, R.; Pomerantz, I.; Puckett, A.; Punjabi, V.; Qian, X.; Qiang, Y.; Ransome, R. D.; Reyhan, M.; Roche, J.; Rousseau, Y.; Saha, A.; Sawatzky, B.; Schulte, E.; Schwamb, M.; Shabestari, M.; Shahinyan, A.; Shneor, R.; Širca, S.; Slifer, K.; Solvignon, P.; Song, J.; Sparks, R.; Subedi, R.; Urciuoli, G. M.; Wang, K.; Wojtsekhowski, B.; Yan, X.; Yao, H.; Zhan, X.; Zhu, X.

    2011-02-03

    We performed high precision measurements of induced and transferred recoil proton polarization in d($\\vec{γ}$, $\\vec{p}$)n for photon energies of 277--357 MeV and θcm = 20 ° -- 120 °. The measurements were motivated by a longstanding discrepancy between meson-baryon model calculations and data at higher energies. Moreover, at the low energies of this experiment, theory continues to fail to reproduce the data, indicating that either something is missing in the calculations and/or there is a problem with the accuracy of the nucleon-nucleon potential being used.

  6. Polarization observables in deuteron photodisintegration below 360 MeV

    DOE PAGES

    Glister, J.; Ron, G.; Lee, B. W.; Gilman, R.; Sarty, A. J.; Strauch, S.; Higinbotham, D. W.; Piasetzky, E.; Allada, K.; Armstrong, W.; et al

    2011-02-03

    We performed high precision measurements of induced and transferred recoil proton polarization in d(more » $$\\vec{γ}$$, $$\\vec{p}$$)n for photon energies of 277--357 MeV and θcm = 20 ° -- 120 °. The measurements were motivated by a longstanding discrepancy between meson-baryon model calculations and data at higher energies. Moreover, at the low energies of this experiment, theory continues to fail to reproduce the data, indicating that either something is missing in the calculations and/or there is a problem with the accuracy of the nucleon-nucleon potential being used.« less

  7. Diffuse cosmic gamma rays at 1-20 MeV: a trace of the dark matter?

    SciTech Connect

    Lawson, Kyle; Zhitnitsky, Ariel R E-mail: arz@phas.ubc.ca

    2008-01-15

    Several independent observations of the galactic core suggest hitherto unexplained sources of energy. The most well known case is the 511 keV line which has proven very difficult to explain with conventional astrophysical positron sources. A similar, but less well known mystery is the excess of gamma ray photons detected by COMPTEL across a broad energy range {approx}1-20 MeV. Such photons are found to be very difficult to produce via known astrophysical sources. We show in this work that dark matter in the form of dense antimatter droplets provides a natural explanation for the observed flux of gamma rays in the {approx}1-20 MeV range. We argue that such photons must always accompany the 511 keV line as they are produced by the same mechanism within our framework. We calculate the spectrum and intensity of the {approx}1-20 MeV gamma rays, and find it to be consistent with the COMPTEL data.

  8. High resolution inelastic gamma-ray measurements with a white neutron source from 1 to 200 MeV

    SciTech Connect

    Nelson, R.O.; Laymon, C.M.; Wender, S.A.

    1990-01-01

    Measurements of prompt gamma rays following neutron-induced reactions have recently been made at the spallation neutron source at the WNR target area of LAMPF using germanium detectors. These experiments provide extensive excitation function data for inelastic neutron scattering as well as for other reactions such as (n,{alpha}), (n,n{alpha}), (n,p), (n,np), (n,nnp) and (n,xn) for 1 {le} {times} {le} 11. The continuous energy coverage available from 1 MeV to over 200 MeV is ideal for excitation function measurements and greatly extends the energy range for such data. The results of these measurements will provide a database for interpretation of gamma-ray spectra from the planned Mars Observer mission, aid in radiation transport calculations, allow verification of nuclear reaction models, and improve the evaluated neutron reaction data base.

  9. Nucleon-induced reactions at intermediate energies: New data at 96 MeV and theoretical status

    NASA Astrophysics Data System (ADS)

    Blideanu, V.; Lecolley, F. R.; Lecolley, J. F.; Lefort, T.; Marie, N.; Ataç, A.; Ban, G.; Bergenwall, B.; Blomgren, J.; Dangtip, S.; Elmgren, K.; Eudes, Ph.; Foucher, Y.; Guertin, A.; Haddad, F.; Hildebrand, A.; Johansson, C.; Jonsson, O.; Kerveno, M.; Kirchner, T.; Klug, J.; Le Brun, Ch.; Lebrun, C.; Louvel, M.; Nadel-Turonski, P.; Nilsson, L.; Olsson, N.; Pomp, S.; Prokofiev, A. V.; Renberg, P.-U.; Rivière, G.; Slypen, I.; Stuttgé, L.; Tippawan, U.; Österlund, M.

    2004-07-01

    Double-differential cross sections for light charged particle production (up to A=4 ) were measured in 96 MeV neutron-induced reactions, at the TSL Laboratory Cyclotron in Uppsala (Sweden). Measurements for three targets, Fe , Pb , and U , were performed using two independent devices, SCANDAL and MEDLEY. The data were recorded with low-energy thresholds and for a wide angular range ( 20° 160° ) . The normalization procedure used to extract the cross sections is based on the np elastic scattering reaction that we measured and for which we present experimental results. A good control of the systematic uncertainties affecting the results is achieved. Calculations using the exciton model are reported. Two different theoretical approaches proposed to improve its predictive power regarding the complex particle emission are tested. The capabilities of each approach is illustrated by comparison with the 96 MeV data that we measured, and with other experimental results available in the literature.

  10. Low energy spread 100 MeV-1 GeV electron bunches from laserwakefiel d acceleration at LOASIS

    SciTech Connect

    Geddes, C.G.R.; Esarey, E.; Michel, P.; Nagler, B.; Nakamura, K.; Plateau, G.R.; Schroeder, C.B.; Shadwick, B.A.; Toth, Cs.; Van Tilborg,J.; Leemans, W.P.; Hooker, S.M.; Gonsalves, A.J.; Michel, E.; Cary, J.R.; and Bruhwiler, D.

    2006-08-01

    Experiments at the LOASIS laboratory of LBNL recentlydemonstrated production of 100 MeV electron beams with low energy spreadand low divergence from laser wakefield acceleration. The radiationpressure of a 10 TW laser pulse guided over 10 diffraction ranges by aplasma density channel was used to drive an intense plasma wave(wakefield), producing acceleration gradients on the order of 100 GV/m ina mm-scale channel. Beam energy has now been increased from 100 to 1000MeV by using a cm-scale guiding channel at lower density, driven by a 40TW laser, demonstrating the anticipated scaling to higher beam energies.Particle simulations indicate that the low energy spread beams wereproduced from self trapped electrons through the interplay of trapping,loading, and dephasing. Other experiments and simulations are alsounderway to control injection of particles into the wake, and henceimprove beam quality and stability further.

  11. Neutron induced fission cross section of {sup 237}Np from 100 keV to 200 MeV

    SciTech Connect

    Tovesson, F.; Hill, T. S.

    2007-03-15

    An experimental program at Los Alamos Neutron Science Center (LANSCE) has been developed to precisely measure fission cross sections over ten decades in incident neutron energy for a range of actinides relevant to advanced nuclear reactor designs and transmutation concepts. The first completed measurement is of {sup 237}Np(n,f), and the above-reaction-threshold part of the measurement is reported here. The result is in close agreement with ENDF/B-VI in the energy region of first- and second-chance fission. The cross section ratio to {sup 235}U is shown to be constant from 30 MeV to the highest measured energy of 200 MeV.

  12. The Measurement and Interpretation of the Cosmic Gamma-ray Spectrum Between 0.3 and 27 Mev as Obtained During the Apollo Mission

    NASA Technical Reports Server (NTRS)

    Peterson, L. E.; Trombka, J. I.

    1973-01-01

    An analysis was made of data collected by Apollo 15 on the total cosmic gamma ray background over the 0.3 to 27 MeV range. Sources of interference with respect to the determination of diffused gamma ray spectrum were considered. Attempts were made to correct the measured spectrum for these background effects.

  13. First Light: MeV Astrophysics from the Moon

    NASA Astrophysics Data System (ADS)

    Miller, Richard S.; Lawrence, David J.

    2016-06-01

    We report evidence of the first astrophysical source detected from the Moon at MeV energies. Our detection of Cygnus X-1 is a validation of a new investigative paradigm in which the lunar environment is intrinsic to the detection approach: the Lunar Occultation Technique (LOT). NASA’s Lunar Prospector mission served as a proxy for a dedicated LOT-based mission. The characteristic signature of temporal modulation, generated by repeated lunar occultations and encoded within acquired gamma-ray data (0.5–9 MeV), is consistent with an unambiguous detection of Cygnus X-1 at 5.4σ significance. Source localization and long-term monitoring capabilities of the LOT are also demonstrated. This “first light” detection verifies the basic tenets of the LOT methodology, reinforces its feasibility as an alternative astronomical detection paradigm for nuclear astrophysics investigations, and is an illustration of the fundamental benefits of the Moon as a platform for science.

  14. Effects of MeV Ions on PE and PVDC

    SciTech Connect

    Evelyn, A.L.; Ila, D.; Zimmerman, R.L.; Bhat, K.; Poker, D.B.; Hensley, D.K.

    1997-12-31

    We studied the effects of 3.5 and 5.0 MeV alpha bombardment on polyethylene and polyvinylidene chloride both of which have simple chemical structures. Using a thin polymer film stacking technique, we were able to map the effects of the MeV alpha particles in their track. The first layer of the thin polymer film stack experienced most of the effects of the electronic energy deposited and the last layer received most of the effects of the nuclear stopping. Using Raman microprobe analysis and measuring the ratio of the formation of graphene structures (G-line) to the disordered (amorphous) carbon line (D-line), we were able to separate the severed bond effects in the end of the alpha particles` track in the last polymer film layers from the effects of the electronic energy deposited in the first polymer film layers. The results are in agreement with our other measurements of each polymer film using FTIR, RBS and resistance measurements.

  15. Effect of 3.0 MeV helium implantation on electrical characteristics of 4H-SiC BJTs

    NASA Astrophysics Data System (ADS)

    Usman, Muhammad; Hallén, Anders; Ghandi, Reza; Domeij, Martin

    2010-11-01

    Degradation of 4H-SiC power bipolar junction transistors (BJTs) under the influence of a high-energy helium ion beam was studied. Epitaxially grown npn BJTs were implanted with 3.0 MeV helium in the fluence range of 1010-1011 cm-2. The devices were characterized by their current-voltage (I-V) behaviour before and after the implantation, and the results showed a clear degradation of the output characteristics of the devices. Annealing these implanted devices increased the interface traps between passivation oxide and the semiconductor, resulting in an increase of base current in the low-voltage operation range.

  16. Wide-range neutron spectrometer on gas proportional counters

    SciTech Connect

    Shvetsov, A.M.; Fomushkin, E.F.

    1994-12-31

    A neutron spectrometer with four cylindrical gas proportional counters was developed, produced and tested in VNIIEF. Active lengths of the counters are concentrated in the range of {approximately}10-100 cm, while the diameters - in the range of {approximately}2-8 cm. Hydrogen, methane, argon, krypton and {sup 3}He were used as working gases. Energy range of the spectrometer constitutes {approximately}0.01MeV, the best energy resolution being 2.1%.

  17. Measurement of prompt X-rays in 238U(n,f) from threshold to 400 MeV. Investigation of fission charge yield evolution

    NASA Astrophysics Data System (ADS)

    Granier, T.; Nelson, R. O.; Ethvignot, T.; Devlin, M.; Fotiades, N.; Garrett, P. E.; Younes, W.

    2013-09-01

    Prompt K X-ray emission yields in the fission induced by neutrons on 238U have been measured for the first time for incident energies ranging from below 1MeV up to 400MeV. Results are used to investigate the evolution with incident neutron energy of the fragment elemental distribution and the X-ray emission probability per element. The progressive increase of the symmetric fission probability with neutron energy is observed in qualitative agreement with Wahl systematics for the primary fission fragment charge yields.

  18. Fixed fluorescent images of an 80 MeV proton pencil beam

    NASA Astrophysics Data System (ADS)

    Warman, J. M.; de Haas, M. P.; Luthjens, L. H.; Denkova, A. G.; Kavatsyuk, O.; van Goethem, M.-J.; Kiewiet, H. H.; Brandenburg, S.

    2013-04-01

    We have used an organic radio-fluorogenic gel to make fixed fluorescent images of the track of an 80 MeV proton pencil beam NB this is not a scintillation effect; rather a small fraction of the molecules of the medium are converted permanently from a non-emissive to an emissive form. The spatial resolution of the images is better than 0.1 mm and the cuboid form of the gels allows the track to be viewed along the direction of the beam or transverse to it. The fluorescence diverges and increases in intensity with increasing depth up to the Bragg peak with 80-20% post-peak fall-off in 1.4±0.1 mm. From the effect of interposed polystyrene sheets on the proton range in the gel, its water equivalent thickness is determined to be 0.91.

  19. Fabrication of waveguides in Yb:YCOB crystal by MeV oxygen ion implantation

    NASA Astrophysics Data System (ADS)

    Jiao, Yang; Chen, Feng; Wang, Xue-Lin; Wang, Ke-Ming; Wang, Lei; Wang, Liang-Ling; Zhang, Huai-Jin; Lu, Qing-Ming; Ma, Hong-Ji; Nie, Rui

    2007-07-01

    Oxygen ions with energies of 6.0 or 3.0 MeV were implanted into y-cut Yb:YCOB crystals at fluences ranging from 5.0 × 10 13 to 2.0 × 10 15 ions/cm 2 at room temperature, forming optical planar waveguide structures. Dark-mode line spectroscopy was applied at two wavelengths, 633 and 1539 nm, in various excitation configurations, showing strong enhancement of one of the indices ( nx) in the implanted near surface. The nx refractive index profile is reconstructed by a reflectivity calculation method and compared to the ion energy losses profiles deduced from SRIM-code simulation. Moreover, the near-field patterns were imaged by an end-fire coupling arrangement.

  20. Ion shaking in the 200 MeV XLS-ring

    SciTech Connect

    Bozoki, E.; Kramer, S.L.

    1992-12-31

    It has been shown that ions, trapped inside the beam`s potential, can be removed by the clearing electrodes when the amplitude of the ion oscillation is increased by vertically shaking the ions. We will report on a similar experiment in the 200 Mev XLS ring. The design of the ion clearing system for the ring and the first results obtained, were already reported. In the present series of experiments, RF voltage was applied on a pair of vertical strip-lines. The frequency was scanned in the range of the ion (from H{sub 2} to CO{sub 2}) bounce frequencies in the ring (1--10 MHz). The response of the beam size, vertical betatron tune and lifetime was studied.

  1. Ion shaking in the 200 MeV XLS-ring

    SciTech Connect

    Bozoki, E.; Kramer, S.L.

    1992-01-01

    It has been shown that ions, trapped inside the beam's potential, can be removed by the clearing electrodes when the amplitude of the ion oscillation is increased by vertically shaking the ions. We will report on a similar experiment in the 200 Mev XLS ring. The design of the ion clearing system for the ring and the first results obtained, were already reported. In the present series of experiments, RF voltage was applied on a pair of vertical strip-lines. The frequency was scanned in the range of the ion (from H[sub 2] to CO[sub 2]) bounce frequencies in the ring (1--10 MHz). The response of the beam size, vertical betatron tune and lifetime was studied.

  2. Effect of MeV nitrogen ion implantation on the resistivity transition in Czochralski silicon wafers

    NASA Astrophysics Data System (ADS)

    Moon, Byeong-Sam; Lee, In-Ji; Park, Jea-Gun

    2012-12-01

    We investigated how MeV nitrogen ion implantation affects the resistivity transition in Czochralski (CZ) silicon wafers. After annealing at 800 °C for 20 h and again at 1000 °C for 10 h, the implanted nitrogen atoms accumulated in the projected range (R P ) for ion doses less than 5 × 1014 cm-2 whereas they accumulated at both R P /2 and R P at ion doses above 3 × 1015 cm-2. These results indicate that no resistivity transition was found at nitrogen ion doses less than 5 × 1013 cm-2 whereas n-/p or n+/p resistivity transition was shown at ion doses higher than 5 × 1014 cm-2. Many fewer than 1% of the implanted nitrogen atoms were ionized after the heat treatment. Thus, the resistivity of nitrogen-doped silicon wafers is more than 100 times higher than that of phosphorous-doped silicon wafers.

  3. Calibration of imaging plates to electrons between 40 and 180 MeV.

    PubMed

    Rabhi, N; Bohacek, K; Batani, D; Boutoux, G; Ducret, J-E; Guillaume, E; Jakubowska, K; Thaury, C; Thfoin, I

    2016-05-01

    This paper presents the response calibration of Imaging Plates (IPs) for electrons in the 40-180 MeV range using laser-accelerated electrons at Laboratoire d'Optique Appliquée (LOA), Palaiseau, France. In the calibration process, the energy spectrum and charge of electron beams are measured by an independent system composed of a magnetic spectrometer and a Lanex scintillator screen used as a calibrated reference detector. It is possible to insert IPs of different types or stacks of IPs in this spectrometer in order to detect dispersed electrons simultaneously. The response values are inferred from the signal on the IPs, due to an appropriate charge calibration of the reference detector. The effect of thin layers of tungsten in front and/or behind IPs is studied in detail. GEANT4 simulations are used in order to analyze our measurements. PMID:27250413

  4. Effect of low doses of 14 MeV neutrons on polymers.

    PubMed

    Rivaton, Agnès; Arnold, Jack; Dos Santos, Morgane; Bussière, Pierre-Olivier; Taviot-Gueho, Christine

    2010-11-01

    The structural modifications of polymers irradiated with 14 MeV neutrons were studied. Two elastomers, a polypropylene-type polymer and poly(ethylene oxide) were exposed to low doses of fast neutrons in the range of 0.3-14 Gy. The radiation damages were observed at the molecular scale by infrared spectroscopy. The morphological changes were investigated by steric exclusion chromatography, insoluble fraction measurements, differential scanning calorimetry and X-ray diffraction. It was found that neutrons provoked oxidation processes accompanied by modifications in the polymer architecture, including chain scissions, crosslinking reactions and changes in the crystallinity. Moreover, the conventional antioxidants were shown to be inefficient in inhibiting the aging of the polymers. These results also suggest that the radiation damages could be used successfully for dosimetry applications using an easily implementable protocol.

  5. Pion scattering from polarized sup 15 N at T sub. pi. =164 MeV

    SciTech Connect

    Meier, R.; Boschitz, E.T.; Ritt, S.; Tacik, R.; Wessler, M. Institut fuer Experimentelle Kernphysik der Universitaet Karlsruhe, Karlsruhe ); Konter, J.A.; Mango, S.; Renker, D.; van den Brandt, B. ); Meyer, W.; Thiel, W. ); Mach, R. ); Amaudruz, P.; Johnson, R.R.; Smith, G.R.; Weber, P. University of Britich Columbia, Vancouver, BC )

    1990-11-01

    The analyzing power {ital A}{sub {ital y}} was measured for {pi}{sup +}{endash}{sup 15}{rvec N} elastic scattering at {ital T}{sub {pi}}=164 MeV between 40{degree} and 100{degree} using a polarized {sup 15}NH{sub 3} target. Within the statistical accuracy of the data {ital A}{sub {ital y}}({theta}) was found to be zero over the full angular range. These data together with differential cross sections from the literature are compared with theoretical predictions based on a momentum-space coupled-channel formalism. While the cross section is very well reproduced there are large discrepancies in the analyzing power for which large spin effects are predicted close to the cross-section minima. Possible deficiencies in the theoretical model are discussed.

  6. Polypropylene compositional evolution under 3.5 MeV He+ ion irradiation

    NASA Astrophysics Data System (ADS)

    Abdesselam, M.; Muller, D.; Djebara, M.; Chami, A. C.; Montgomery, P.

    2012-05-01

    A helium beam at 3.5 MeV was used to induce damage in thin polypropylene film of 5.1 μm in thickness. The fluence ranges from 2 × 1012 to 3.5 × 1015 cm-2. The evolution of the atomic composition (C and H) as a function of the fluence was investigated in situ by forward elastic scattering (C(α, α)C) and hydrogen elastic recoil detection (H(α, H)α), respectively. The helium beam was used at the same time for irradiation and analysis. In respect to the high sensitivity of the polypropylene to radiation damage, the beam current was kept at very low intensity of 0.5 nA. The mass loss becomes significant above a fluence of ˜5 × 1013 He+ cm-2. The carbon depletion levels off at a fluence of ˜5 × 1014 He+ cm-2 approximately while hydrogen loss continues to be present along the whole of the studied fluence range. The final carbon and hydrogen losses, at the highest fluence, are around 17% and 48% of their initial contents, respectively. Satisfactory fits to the release curves have been obtained in the framework of the bulk molecular recombination model (BMR). The deduced hydrogen and carbon release cross sections are 7.8 and 65.2 × 10-16 cm2, respectively. A comparison with our previous measurements of polyethylene terephthalate (PET) film irradiated with 3.7 MeV He+ beam is made.

  7. Study of the radioactivity induced in air by a 15-MeV proton beam.

    PubMed

    Braccini, S; Ereditato, A; Nesteruk, K P; Scampoli, P; Zihlmann, K

    2015-02-01

    Radioactivity induced by a 15-MeV proton beam extracted into air was studied at the beam transport line of the 18-MeV cyclotron at the Bern University Hospital (Inselspital). The produced radioactivity was calculated and measured by means of proportional counters located at the main exhaust of the laboratory. These devices were designed for precise assessment of air contamination for radiation protection purposes. The main produced isotopes were (11)C, (13)N and (14)O. Both measurements and calculations correspond to two different irradiation conditions. In the former, protons were allowed to travel for their full range in air. In the latter, they were stopped at the distance of 1.5 m by a beam dump. Radioactivity was measured continuously in the exhausted air starting from 2 min after the end of irradiation. For this reason, the short-lived (14)O isotope gave a negligible contribution to the measured activity. Good agreement was found between the measurements and the calculations within the estimated uncertainties. Currents in the range of 120-370 nA were extracted in air for 10-30 s producing activities of 9-22 MBq of (11)C and (13)N. The total activities for (11)C and (13)N per beam current and irradiation time for the former and the latter irradiation conditions were measured to be (3.60 ± 0.48) × 10(-3) MBq (nA s)(-1) and (2.89 ± 0.37) × 10(-3) MBq (nA s)(-1), respectively.

  8. Spectrum of atmospheric gamma rays to 10 MeV at lambda = 40 deg. [as function of altitude

    NASA Technical Reports Server (NTRS)

    Peterson, L. E.; Schwartz, D. A.; Ling, J. C.

    1973-01-01

    Results of measurements of the differential counting rate spectra due to atmospheric gamma rays as a function of altitude to 3.6 g/sq cm over Texas. Two gain settings and a 128-channel pulse height analyzer were used to cover the range from 0.2 to 10 MeV. The detector was a 7.6 x 7.6 cm NaI crystal, which was surrounded on five sides by a 2-cm-thick plastic anticoincidence shield for charged particle rejection. The system had a nearly isotropic response to photons above 0.2 MeV. The spectrum at ceiling appeared as a steep continuum with a power-law index of about 1.4. The only obvious feature was the 0.51-MeV positron annihilation line. The spectral shape was independent for depths less than 20 g/sq cm, the absolute intensity varying in proportion to the intensity of the cosmic ray secondary charged particles. Also, at depths less than 30 g/sq cm the observed flux variation with altitude can be described in terms of an empirical depth-dependent source function.

  9. Elastic and inelastic scattering of polarized protons from carbon-12 at 400, 600, and 700 MeV

    SciTech Connect

    Jones, K.W.

    1984-04-01

    Good resolution cross section and analyzing power (p vector, p') data for many states in /sup 12/C up to an excitation energy of 21 MeV and spanning a momentum transfer range of 0.3 to 2.1 fm/sup -1/ were obtained using the High Resolution Spectrometer at the Clinton P. Anderson Meson Physics Facility at incident beam energies of 398, 597, and 698 MeV. Optical model potentials were obtained from the elastic scattering data. Inelastic data were analyzed in the Distorted Wave Impulse Approximation using the Love-Franey effective nucleon-nucleon interaction. The energy dependent isoscalar natural parity cross sections were underestimated, while phase difficulties were encountered in fitting analyzing powers. The energy independent isovector natural parity cross sections were reasonably reproduced, but analyzing powers were not, the calculations yielding positive trends whereas the data are of opposite sign. The energy independent isoscalar and isovector unnatural parity cross sections were quite well reproduced up to moderate momentum transfers, and striking successes were observed for some analyzing power data. Systematics of energy dependence together with the results of the DWIA calculations permitted the assignment of spin, parity and isospin quantum numbers to states in the 18-21 MeV excitation region. 64 references.

  10. Calibration of indium response functions in an Au-In-BSE system up to 800 MeV.

    PubMed

    Wang, Zhonglu; Howell, Rebecca M; Burgett, Eric A; Kry, Stephen F; Hertel, Nolan E; Salehpour, Mohammad

    2010-06-01

    Calibration of the response functions of a gold (Au)-indium (In) dual foil Bonner sphere extended (BSE) system was described. The response of the In and Au foil of the system was calculated using MCNPX code with different activation cross-sectional libraries: (ACTL and ENDF VI for gold and ACTL and 532DOS2 for In). To verify and correct the calculated response functions the Bonner sphere set (BSS) was irradiated using (252)Cf and (241)AmBe sources of known neutron strengths for neutrons ranging from thermal to 20 MeV, and was irradiated at the 800-MeV neutron beam of the Los Alamos Neutron Science Center. The neutron spectrum of the 800 MeV beam was determined using time-of-flight (TOF) technique. We observed that the uncertainty of activation cross section in the resonance region can result in great uncertainty in the MCNPX-calculated response functions of activation foil-based BSS. The MCNPX-calculated response functions must be corrected using neutron sources of known spectrum and strength.

  11. Two charmoniumlike charged axial resonances near 3885 MeV

    NASA Astrophysics Data System (ADS)

    Voloshin, M. B.

    2016-10-01

    It is argued that the charged Zc+(3885 ) resonance, treated as a "molecular" state of charmed D and D* mesons, is likely to consist of two peaks unequally coupled to the D*+D¯0 and D+D¯*0 channels. The peaks should be split in mass by at least approximately 1.5 MeV. This behavior arises from an enhancement of the effect of isospin violation in the masses of the D and D* mesons due to apparent suppression of forces between the mesons depending on the spins of the heavy as well as the light quarks. The suggested double-peak structure can be studied either by direct shape measurement in the channels with heavy mesons, or by isospin-violating transitions from Zc±(3885 ) to the states of charmonium plus a light meson.

  12. The 50 MeV Beam Test Facility at LBL

    SciTech Connect

    Leemans, W.; Behrsing, G.; Kim, K.J.; Krupnick, J.; Matuk, C.; Selph, F.; Chattopadhyay, S.

    1993-05-01

    A new beam line, expected to be built by September 1993, will transport the 50 MeV electron beam from the ALS LINAC into an experimental area to support various R&D activities in the Center for Beam Physics at LBL. A variety of experiments are planned involving the interaction of such a relativistic electron beam with plasmas (plasma focusing), laser beams (generation of femtosecond X-ray pulses) and electromagnetic cavities (Crab cavities etc....). The beam line is designed using the measured emittance and Twiss parameters of the ALS linac. It accommodates the different requirements of the various experiments on the electron beam properties (charge, energy, pulse length) and on the handling of the beam before and after the interaction point. Special attention has also been given to incorporate diagnostics for measuring the beam properties (such as the electron energy, bunch length and charge) needed in the interpretation of the experiments.

  13. Detectors for energies less than 10 MeV

    NASA Technical Reports Server (NTRS)

    1981-01-01

    In the energy domain 100 keV to 10 MeV, both crystal scintillations and semiconductors are widely used for gamma ray detectors in spectrometer systems. These detectors' operation depend on the fact that gamma rays lose energy by ionization in these materials and electrons and holes are produced. In the case of semiconductors, these electrons and holes are collected by an electric field, and they provide an electric signal that is a direct measure of the energy lost by the gamma ray in the material. Scintillation detectors depend on a further conversion of the energy lost in electron hole pair production to the production of photons. A photomultiplier tube measures the intensity of the photon flux, and an electrical pulse proportional to the photon intensity is produced at the photomultiplier output.

  14. Little Boy neutron spectrum below 3 MeV

    SciTech Connect

    Evans, A.E.; Bennett, E.F.; Yule, T.J.

    1984-01-01

    The leakage neutron spectrum from the Little Boy replica has been measured from 12 keV to 3 MeV using a high-resolution /sup 3/He ionization chamber, and from 1 keV to 3 MeV using proton-recoil proportional counters. The /sup 3/He-spectrometer measurements were made at distances of 0.75 and 2.0 m from the active center and at angles of 0/sup 0/, 45/sup 0/, and 90/sup 0/ with respect to the axis of the assembly. Proton-recoil measurments were made at 90/sup 0/ to the assembly axis at distances of 0.75 and 2.0 m, with a shielded measurement made at 2.0 m to estimate background due to scattering. The /sup 3/He spectrometer was calibrated at Los Alamos using monoenergetic /sup 7/Li(p,n)/sup 7/Be neutrons to generate a family of response functions. The proton-recoil counters were calibrated at Argonne by studying the capture of thermal neutrons by nitrogen in the counters, by observation of the 24-keV neutron resonance in iron, and by relating to the known hydrogen content of the counters. The neutron spectrum from Little Boy was found to be highly structured, with peaks corresponding to minima in the iron total neutron cross section. In particular, influence of the 24-keV iron window was evident in both sets of spectra. The measurements provide information for dosimetry calculations and also a valuable intercomparison of neutron spectrometry using the two different detector types. Spectra measured with both detectors are in essential agreement. 8 references, 7 figures, 2 tables.

  15. Compton-Pair Production Space Telescope (ComPair) for MeV Gamma-ray Astronomy

    NASA Astrophysics Data System (ADS)

    Moiseev, Alexander

    2016-04-01

    The gamma-ray energy range from a few hundred keV to a few hundred MeV has remained largely unexplored, mainly due to the challenging nature of the measurements, since the pioneering, but limited, observations by COMPTEL on the Compton Gamma-Ray Observatory (1991- 2000). This energy range is a transition region between thermal and nonthermal processes, and accurate measurements are critical for answering a broad range of astrophysical questions. We are developing a MIDEX-scale wide-aperture discovery mission, ComPair (Compton-Pair Production Space Telescope), to investigate the energy range from 200 keV to > 500 MeV with high energy and angular resolution and with sensitivity approaching a factor of 100 better than COMPTEL. This instrument will be equally capable to detect both Compton-scattering events at lower energy and pair-production events at higher energy. ComPair will build on the heritage of successful space missions including Fermi LAT, AGILE, AMS and PAMELA, and will utilize well-developed space-qualified detector technologies including Si-strip and CdZnTe-strip detectors, heavy inorganic scintillators, and plastic scintillators.

  16. Modification of radiobiological effects of 171 MeV protons by elements of physical protection

    NASA Astrophysics Data System (ADS)

    Bulinina, Taisia; Shurshakov, Vyacheslav; Ivanov, Alexander; Molokanov, Alexander

    2016-07-01

    Space radiation includes protons of various energies. Physical protection is effective in the case of low energy protons (50-100 MeV) and becomes insufficient for radiation with a high part of high-energy protons. In the experiment performed on outbred mice, the purpose of the study was to evaluate the radiobiological effect of 171 MeV protons and protons modified by elements of physical protection of the spacecraft, on a complex of indicators of the functional condition of the system hematopoiesis and the central nervous system in 24 hours after irradiation at 20 cGy dose. The spacecraft radiation protection elements used in the experiment were a construction of wet hygiene wipes called a «protective curtain», and a glass plate imitating an ISS window. Mass thickness of the " protective curtain" in terms of water equivalent was ̴ 6,2 g/cm2. Physical shielding along the path of 171 MeV protons increases their linear energy transfer leading to the absorbed dose elevation and strengthening of the radiobiological effect. In the experiment, the two types of shielding together raised the absorbed dose from 20 to 23.2 cGy. Chemically different materials (glass and water in the wipes) were found to exert unequal modifying effects on physical and biological parameters of the proton-irradiated mice. There was a distinct dose-dependent reduction of bone marrow cellularity within the dose range from 20 cGy to 23.2 cGy in 24 hours after exposure. No modifying effect of the radiation protection elements on spontaneous motor activity was discovered when compared with entrance protons. The group of animals protected by the glass plate exhibited normal orientative-trying reactions and weakened grip with the forelimbs. The effects observed in the experiment indicate the necessity to carry out comprehensive radiobiological researches (physical, biological and mathematical) in assessing the effects of physical protection, that are actual for ensuring radiation safety of crews in

  17. Monte Carlo 20 and 45 MeV Bremsstrahlung and dose-reduction calculations

    SciTech Connect

    Goosman, D.R.

    1984-08-14

    The SANDYL electron-photon coupled Monte Carlo code has been compared with previously published experimental bremsstrahlung data at 20.9 MeV electron energy. The code was then used to calculate forward-directed spectra, angular distributions and dose-reduction factors for three practical configurations. These are: 20 MeV electrons incident on 1 mm of W + 59 mm of Be, 45 MeV electrons of 1 mm of W and 45 MeV electrons on 1 mm of W + 147 mm of Be. The application of these results to flash radiography is discussed. 7 references, 12 figures, 1 table.

  18. Recombination characteristics in 2-3 MeV protons irradiated FZ Si

    NASA Astrophysics Data System (ADS)

    Gaubas, E.; Čeponis, T.; Uleckas, A.; Vaitkus, J.; Raisanen, J.

    2010-01-01

    Combined analysis of the carrier recombination and generation lifetime as well as reverse recovery durations ( τ RR), dependent on proton irradiation fluence in the range of 7×10 12-7×10 14 p/cm 2, has been performed in FZ silicon PIN diodes and wafer structures. A δ-layer and triangle profiles of radiation induced defects were formed by varying energy of protons in the range 2-3 MeV. Carrier decay constituents and values of recombination lifetime have been evaluated by employing a microwave probed photoconductivity transient technique, while deep levels spectra ascribed to generation lifetime variations have been examined by exploiting capacitance deep-level transient (DLTS) spectroscopy. Recombination lifetime decreases from several μs to few ns, while DLTS spectra show an increase in the amplitude of a DLTS peak at 170 K with irradiation fluence. Transforms of DLTS spectra and a decrease in density of the majority carrier traps have been revealed after 24 h isochronal anneals in the range of temperatures of 80-420 °C. Inhomogeneous depth distribution of recombination lifetime in proton irradiated samples has been revealed from the cross-sectional scans of the excess carrier lifetime measured by MW-PC technique and compared for δ-layer and triangle profiles of radiation induced defects. After isochronal anneals, the τ RR changes its behaviour as a function of irradiation fluence.

  19. Portable 1,5 MeV X-Band Linac For Non-destructive Radiography

    NASA Astrophysics Data System (ADS)

    Saversky, A. J.; Rodionov, A. E.; Shaltyrev, A. P.; Shchedrin, I. S.

    1997-05-01

    Portable linear electron accelerator Y-34 developed in Small Accelerator Laboratory of MEPhI for non-destructive industrial radiography. This Linac is a fully self-contained device with the exception of external electric power 220Vx50Gz, 1 phase, 5 kVA. Full mass of Linac Y-34 - less than 300 kg. The Radiographic parameters: Nominal Energy - 1,5 MeV; Energy Range - 0,7...1,8 MeV; Maximum pulse current - 100 mA; Maximum Intensity - 15 R/min@m; Focal spot size - less than 2 mm. The Linac is comprised of 4 subassemblies. The X-ray head with weight less than 100 kg, dimensions: 0,7x0,7x1,0 m contains the traveling-wave accelerating structure with lens 0,4 m, electron gun, vacuum pump, tungsten target and RF-system with 500-kW magnetron. The permanent magnets focusing system provides focal spot less than 2 mm. The high voltage power unit consist of a line-type magnetron/electron gun modulator 2 kW power supply, the weight is equal 70 kg. The self-contained cooling water supply provides temperature controlled water for accelerator structure and magnetron. The control console allows convenient monitoring of critical system and Linac parameters by manual or remote computer. Portable X-band Linac Y-34 is the effective X - ray and/or electron beam source for such applications as non-destructive examination of nuclear reactor systems, solid rocket motors, technology research.

  20. Validation of the GEANT4 simulation of bremsstrahlung from thick targets below 3 MeV

    NASA Astrophysics Data System (ADS)

    Pandola, L.; Andenna, C.; Caccia, B.

    2015-05-01

    The bremsstrahlung spectra produced by electrons impinging on thick targets are simulated using the GEANT4 Monte Carlo toolkit. Simulations are validated against experimental data available in literature for a range of energy between 0.5 and 2.8 MeV for Al and Fe targets and for a value of energy of 70 keV for Al, Ag, W and Pb targets. The energy spectra for the different configurations of emission angles, energies and targets are considered. Simulations are performed by using the three alternative sets of electromagnetic models that are available in GEANT4 to describe bremsstrahlung. At higher energies (0.5-2.8 MeV) of the impinging electrons on Al and Fe targets, GEANT4 is able to reproduce the spectral shapes and the integral photon emission in the forward direction. The agreement is within 10-30%, depending on energy, emission angle and target material. The physics model based on the Penelope Monte Carlo code is in slightly better agreement with the measured data than the other two. However, all models over-estimate the photon emission in the backward hemisphere. For the lower energy study (70 keV), which includes higher-Z targets, all models systematically under-estimate the total photon yield, providing agreement between 10% and 50%. The results of this work are of potential interest for medical physics applications, where knowledge of the energy spectra and angular distributions of photons is needed for accurate dose calculations with Monte Carlo and other fluence-based methods.

  1. ICPP: Scale size of of magnetic turbulence as probed with 30 MeV runaway electrons

    NASA Astrophysics Data System (ADS)

    Jaspers, Roger

    2000-10-01

    This paper reviews results concerning generation, confinement and transport of runaway electrons in the energy range 20-30 MeV in the TEXTOR tokamak. For future fusion reactors, it is of major importance to know the processes of runaway generation and runaway loss after disruptions, because of the potential damage to first wall components. Second, since the runaway electrons are effectively collisionless, their confinement is determined by the magnetic field turbulence. In this way the runaway transport provides a unique opportunity to probe turbulence in the core of a thermonuclear plasma. Runaway electrons above 20 MeV emit synchrotron radiation in the (near) infrared, which can easily be detected by thermographic cameras. This technique is developed and exploited at the TEXTOR-94 tokamak and has resulted in some spectacular results. These include: the experimental evidence of the secondary (`knock-on') runaway generation; the discovery of the runaway snake; the observation of disruption generated runaways; the probing of magnetic turbulence in the core of the plasma in Ohmic and additionally heated plasmas. The paper reviews these results with special emphasis on the subject of probing magnetic turbulence in the core of the plasma. Measurements in the TEXTOR-94 tokamak show that after switching on Neutral Beam Injection, the runaway population decays. The decay only starts with a significant delay, which decreases with increasing NBI heating power. This delay provides direct evidence of the energy dependence of runaway confinement, which is expected if magnetic modes govern the loss of runaway electrons. These observations allow to estimate the mode width δ of the magnetic perturbations:δ smaller than 0.5 cm in Ohmic discharges, increasing to δ=3D 4.4 cm for 0.6 MW NBI power.

  2. A comparative study of 30MeV boron{sup 4+} and 60MeV oxygen{sup 8+} ion irradiated Si NPN BJTs

    SciTech Connect

    Kumar, M. Vinay Krishnaveni, S.; Yashoda, T.; Dinesh, C. M.; Krishnakumar, K. S.; Jayashree, B.; Ramani

    2015-06-24

    The impact of 30MeV boron{sup 4+} and 60MeV oxygen{sup 8+} ion irradiation on electrical characteristics of 2N3773 Si NPN Bipolar junction transistors (BJTs) is reported in the present study. The transistors were decapped and irradiated at room temperature. Gummel characteristics, DC current gain and Capacitance-voltage (C-V) characteristics were studied before and after irradiation at different fluences. DC current gain has decreased significantly in both boron and oxygen ion irradiation. Also the value of capacitance decreased 3-4 times with increase in fluence. Both 30MeV boron ion and 60MeV oxygen ion induced similar extent of degradation in electrical characteristics of the transistor.

  3. A comparative study of 30MeV boron4+ and 60MeV oxygen8+ ion irradiated Si NPN BJTs

    NASA Astrophysics Data System (ADS)

    Kumar, M. Vinay; Yashoda, T.; Dinesh, C. M.; Krishnakumar, K. S.; Jayashree, B.; Ramani, Krishnaveni, S.

    2015-06-01

    The impact of 30MeV boron4+ and 60MeV oxygen8+ ion irradiation on electrical characteristics of 2N3773 Si NPN Bipolar junction transistors (BJTs) is reported in the present study. The transistors were decapped and irradiated at room temperature. Gummel characteristics, DC current gain and Capacitance-voltage (C-V) characteristics were studied before and after irradiation at different fluences. DC current gain has decreased significantly in both boron and oxygen ion irradiation. Also the value of capacitance decreased 3-4 times with increase in fluence. Both 30MeV boron ion and 60MeV oxygen ion induced similar extent of degradation in electrical characteristics of the transistor.

  4. Effect of 1.33 Mev gamma radiation and 0.5 Mev electrons on the mechanical properties of graphite fiber composites

    NASA Technical Reports Server (NTRS)

    Fornes, R. E.; Memory, J. D.; Naranong, N.

    1982-01-01

    Epoxy/graphite fiber, polyimide/graphite fiber, and polysulfone/graphite fiber composites were exposed to 1.33 Mev gamma irradiation and 0.5 Mev electron bombardment for varying periods of time. The effects of the irradiation treatments on the breaking stress and Young's modulus were studied by a three point bending test. Effects were small; both electron radiation up to 5000 Mrad and gamma radiation up to 350 Mrad resulted in slight increases in both stress and modulus.

  5. Observations of solar flare photon energy spectra from 20 keV to 7 MeV

    NASA Technical Reports Server (NTRS)

    Yoshimori, M.; Watanabe, H.; Nitta, N.

    1985-01-01

    Solar flare photon energy spectra in the 20 keV to 7 MeV range are derived from the Apr. 1, Apr. 4, apr. 27 and May 13, 1981 flares. The flares were observed with a hard X-ray and a gamma-ray spectrometers on board the Hinotori satellite. The results show that the spectral shape varies from flare to flare and the spectra harden in energies above about 400 keV. Effects of nuclear line emission on the continuum and of higher energy electron bremsstrahlung are considered to explain the spectral hardening.

  6. The influence of 175 MeV nickel ion irradiation on the electrical characteristics of power transistors (HF13)

    NASA Astrophysics Data System (ADS)

    Pushpa, N.; Praveen, K. C.; Gnana Prakash, A. P.; Naik, P. S.; Gupta, S. K.; Revannasiddaiah, D.

    2012-10-01

    The dc electrical characteristics of NPN RF power transistors were studied systematically before and after 175 MeV Ni13+ ion and Co-60 gamma irradiation in the dose range from 100 krad to 100 Mrad. The transistor parameters such as excess base current (ΔIB= IBpost-IBpre), dc current gain (hFE), and collector-saturation current (ICSat) were studied. The base current (IB) was found to increase significantly after irradiation and this in turn decreases the hFE of the transistors. Further, the output characteristics of the irradiated devices exhibit the decrease in the collector current at the saturation region (ICSat) with increase of radiation dose.

  7. Variation of carrier concentration and interface trap density in 8MeV electron irradiated c-Si solar cells

    SciTech Connect

    Bhat, Sathyanarayana Rao, Asha; Krishnan, Sheeja; Sanjeev, Ganesh; Suresh, E. P.

    2014-04-24

    The capacitance and conductance measurements were carried out for c-Si solar cells, irradiated with 8 MeV electrons with doses ranging from 5kGy – 100kGy in order to investigate the anomalous degradation of the cells in the radiation harsh environments. Capacitance – Voltage measurements indicate that there is a slight reduction in the carrier concentration upon electron irradiation due to the creation of radiation induced defects. The conductance measurement results reveal that the interface state densities and the trap time constant increases with electron dose due to displacement damages in c-Si solar cells.

  8. Extending the dynamic range of nuclear pulse spectrometers

    SciTech Connect

    Pullia, A.; Zocca, F.; Pascovici, G.; Bazzacco, D.

    2008-03-15

    Using an innovative time-varying front-end electronics in conjunction with a bulky coaxial high-purity germanium detector, we were able to extend the range of the radionuclide spectra well beyond the analog to digital converter (ADC) saturation point. The electronics automatically conditions the signal for digital-filtering optimization if it is in the ADC voltage range and for time-over-threshold analysis if it exceeds the ADC range. A high spectroscopic resolution has been achieved in both operation ranges. An unprecedented wide energy range from 5 keV to 150 MeV of equivalent energy, or 90 dB, has been obtained using a single acquisition chain, while maintaining a high-energy resolution in the whole spectrum. For example, with an ADC range of 3 MeV a resolution has been obtained of 1.3/2.2 keV full width at half maximum on the 122/1332 keV gamma-ray lines of {sup 57}Co and {sup 60}Co, and of <0.4% in the time-over-threshold region, or for energy deposits beyond 3 MeV.

  9. Measurements of radiological data of some amino acids in the energy range 0.122-1.330MeV

    NASA Astrophysics Data System (ADS)

    Lokhande, Rajkumar M.; More, Chaitali V.; Surung, Bharat S.; Raut, Siddheshwar D.; Pawar, Pravina P.

    2016-05-01

    Radiological parameters such as μm, σt, σe, Zeff and Neff of amino acids, namely Lysine (C6H15N2O2), Histidine (C6H9N3O2) and Arginine (C6H15N4O2), were measured using NaI (Tl)-based gamma spectrometry. Radioactive sources used in the study are 57Co, 133Ba, 137Cs, 54Mn, 60Co and 22Na. Gamma ray transmission method in a narrow beam good geometry set up was used in the study. The measured data were compared against XCOM-based data. The agreement is within 2%.

  10. 10B(n, Z) measurements in the energy range 0.7 to 5.0 MeV

    DOE PAGES

    Massey, T. N.; Ralston, J.; Grimes, S. M.; Haight, R. C.

    2014-09-03

    Four ΔE E telescopes were used at the WNR (n,Z) station to investigate the production of charged particles from 10B. The telescope consisted of a gas proportional detector and a silicon surface barrier detector. The flux was determined using a 238U fission chamber. A clear separation of the ground state alpha group and first excited state a was not achieved due to the target thickness. Proton emission was also observed. Furthermore, the proton branch was up to an order of magnitude larger than predicted in ENDF/B-VII A simple R-matrix analysis has been performed on the available data

  11. Little Boy neutron spectrum below 1 MeV

    SciTech Connect

    Evans, A.E.

    1984-01-01

    A high-resolution /sup 3/He ionization chamber of the type development by Cuttler and Shalev was used to study the neutron spectrum from the Little Boy mockup. Measurements were made at distances of 0.75 and 2.0 m and at angles of 0/sup 0/, 45/sup 0/, and 90/sup 0/ with respect to the axis of the assembly, which was operated at power levels from 8.6 to 450 mW. Detector efficiency as a function of energy as well as parameters for correction of pulse-height distributions for proton-recoil and wall effects were determined from a set of response functions for monoenergetic neutrons measured at the Los Alamos 3.75-MeV Van de Graaff Accelerator Facility. Pulse-shape discrimination was used to separate /sup 3/He-recoil pulses from the pulse-height distribution. The spectrum was found to be highly structured, with peaks corresponding to minima in the total neutron cross section of iron. In particular, 15% of the neutrons above the epithermal peak in energy were found to be in the 24-keV iron window. Lesser peaks out to 700 keV are also attributable to filtering action of the weapon's heavy iron casing. Data taken using experimental proton-recoil proportional counters are compared with the high-resolution spectra.

  12. Multipurpose 5-MeV linear induction accelerator

    NASA Astrophysics Data System (ADS)

    Birx, D. L.; Hawkins, S. A.; Poor, S. E.; Reginato, L. L.; Smith, M. W.

    1984-06-01

    Although linear induction accelerators (LIAs) are quite reliable by most standards, they are limited in repeating rate, average power, and reliability because the final stage of energy delivery is based on spark gap performance. In addition, they have a low duty factor of operation. To provide a higher burst rate and greater reliability, new technology was used to develop a magnetic pulse compression scheme that eliminates all spark gaps and exceeds requirements. The magnetic drive system are tailored to drive induction cells from a few kA to over 10 kA at 500 kV, with average beam power levels in the megawatts. This new 5-MeV, 2.5-kA LIA under construction at the Lawrence Livermore National Laboratory (LLNL) will be used for the development of high brightness sources and will provide a test bed for the new technology, which should lead to LIAs that surpass the radio frequency linacs for efficiency and reliability, as well as fit other industrial applications, such as sewage sterilization.

  13. Multipurpose 5-MeV linear induction accelerator

    SciTech Connect

    Birx, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L. Smith, M.W.

    1984-06-11

    Although linear induction accelerators (LIAs) are quite reliable by most standards, they are limited in repeating rate, average power, and reliability because the final stage of energy delivery is based on spark gap performance. In addition, they have a low duty factor of operation. To provide a higher burst rate and greater reliability, the researchers used new technology to develop a magnetic pulse compression scheme that eliminates all spark gaps and exceeds requirements. The paper describes the scheme. The magnetic drive system can be tailored to drive induction cells from a few kA to over 10 kA at 500 kV, with average beam power levels in the megawatts. This new 5-MeV, 2.5-kA LIA under construction at the Lawrence Livermore National Laboratory (LLNL) will be used for the development of high brightness sources and will provide a test bed for the new technology, which should lead to LIAs that surpass the radio frequency linacs for efficiency and reliability, as well as fit other industrial applications, such as sewage sterilization.

  14. 400 MeV upgrade for the Fermilab linac

    SciTech Connect

    MacLachlan, J.A.

    1989-03-24

    Fermilab has plans for a comprehensive accelerator upgrade to open new possibilities for both the fixed target and collider experimental programs. An early step in this program is to increase the energy of the linac from 200 to 400 MeV by replacing the last four of its nine 201 MHz Alvarez tanks with twenty-eight 805 MHz side-coupled cavity chains operating at about 8 MV/m average axial field. The principal purpose is to reduce the incoherent spacecharge tuneshift at injection into the Booster which currently limits both the brightness of the beam, an important determinant of collider luminosity, and total intensity to produce both the antiprotons for the collider and the beams to fixed target experimental areas. Other consequences of higher Booster injection energy expected to contribute to some degree of higher intensity limits and improved operational characteristics include improved quality of the guide field at injection, reduced frequency swing for the rf systems, and smaller emittance for the injected beam. The linac upgrade project has moved from a 1986 study through a development project including structure models and numerical studies to a full-feature module prototyping starting this year.

  15. 2 MeV linear accelerator for industrial applications

    NASA Astrophysics Data System (ADS)

    Smith, Richard R.; Farrell, Sherman R.

    1997-02-01

    RPC Industries has developed a high average power scanned electron beam linac system for medium energy industrial processing, such as in-line sterilization. The parameters are: electron energy 2 MeV; average beam current 5.0 mA; and scanned width 0.5 meters. The control system features data logging and a Man-Machine Interface system. The accelerator is vertically mounted, the system height above the floor is 3.4 m, and the footprint is 0.9×1.2 meter2. The typical processing cell inside dimensions are 3.0 m by 3.5 m by 4.2 m high with concrete side walls 0.5 m thick above ground level. The equal exit depth dose is 0.73 gm cm-2. Additional topics that will be reported are: throughput, measurements of dose vs depth, dose uniformity across the web, and beam power by calorimeter and magnetic deflection of the beam.

  16. ETFE polymer bombarded with 1 MeV proton

    NASA Astrophysics Data System (ADS)

    Parada, M. A.; de Almeida, A.; Muntele, I.; Muntele, C.; Delalez, N.; Ila, D.

    2005-12-01

    The ethylenetetrafluoroethylene (ETFE) is a polymer formed by alternating ethylene and tetrafluoroethylene segments. It has high impact resistance and useful mechanical properties. ETFE can be used as components of pumps, valves, tie wraps, and electrical components. It can also be applied in the field of medical physics as intra venous catheters and as radiation dosimeter. When a material is exposed to the ionizing radiation, it suffers damage that depends on the type, energy and intensity of the radiation. In order to determine the radiation damage mechanism, ETFE films were bombarded with 1 MeV protons to the fluence between 1 × 1011 and 1 × 1016 protons/cm2 and the chemical species emitted during the bombardment were measured with residual gas analysis (RGA) and show that HF gas is the entity preferentially emitted. Optical absorption photospectrometry (OAP) and attenuated total reflectometry fourier transform infrared (ATR-FTIR) shows quantitative chemical evidence of the damage. Our results show that damage is detectable at low proton fluence, but damage that can compromise the application in dosimetry occurs only for fluence greater than 1014 protons/cm2.

  17. Determination of the {sup 233}Pa(n,f) reaction cross section from 11.5 to 16.5 MeV neutron energy by the hybrid surrogate ratio approach

    SciTech Connect

    Nayak, B. K.; Saxena, A.; Biswas, D. C.; Mirgule, E. T.; John, B. V.; Santra, S.; Vind, R. P.; Choudhury, R. K.; Ganesan, S.

    2008-12-15

    A new hybrid surrogate ratio approach has been employed to determine neutron-induced fission cross sections of {sup 233}Pa in the energy range of 11.5 to 16.5 MeV for the first time. The fission probability of {sup 234}Pa and {sup 236}U compound nuclei produced in {sup 232}Th({sup 6}Li, {alpha}){sup 234}Pa and {sup 232}Th({sup 6}Li, d){sup 236}U transfer reaction channels has been measured at E{sub lab}=38.0 MeV in the excitation energy range of 17.0 to 22.0 MeV within the framework of the absolute surrogate method. The {sup 233}Pa(n,f) cross sections are then deduced from the measured fission decay probability ratios of {sup 234}Pa and {sup 236}U compound nuclei using the surrogate ratio method. The {sup 233}Pa(n,f) cross section data from the present experiment along with the data from the literature, covering the neutron energy range of 1.0 to 16.5 MeV have been compared with the predictions of statistical model code EMPIRE-2.19. While the present data are consistent with the model predictions, there is a discrepancy between the earlier experimental data and EMPIRE-2.19 predictions in the neutron energy range of 7.0 to 10.0 MeV.

  18. Elastic scattering of polarised deuterons from 16O at 200, 400 and 700 MeV

    NASA Astrophysics Data System (ADS)

    van Sen, Nguyen; Yanlin, Ye; Arvieux, J.; Gaillard, G.; Bonin, B.; Boudard, A.; Bruge, G.; Lugol, J. C.; Hasegawa, T.; Soga, F.; Antonuk, L. E.; Cameron, J. M.; Lam, S. T.; Neilson, G. C.; Roy, G.; Sheppard, D. M.; Babinet, R.

    1987-03-01

    Angular distributions of cross section, and Ay and Ayy analysing powers were measured for polarised deuteron elastic scattering from 16O at 200, 400 and 700 MeV. The data at 200 MeV bear evidence of the nuclear rainbow phenomenon while those at 400 and 700 MeV are reminiscent of the proton scattering results at equivalent energies. The data were analysed in terms of the optical model. The real central potential shape changes from an attractive Woods-Saxon form at 200 MeV to a wine-bottle-bottom form with a repulsive interior at 700 MeV. The total reaction cross sections deduced display a clear nuclear transparency effect in the present energy domain in agreement with predictions from the Glauber theory optical limit. Comparison with previous results for 40Ca and 58Ni targets is made.

  19. EGRET Diffuse Gamma Ray Maps Between 30 MeV and 10 GeV

    NASA Technical Reports Server (NTRS)

    Cillis, A, N.; Hartman, R. C.

    2004-01-01

    This paper presents all-sky maps of diffuse gamma radiation in various energy ranges between 30 MeV and 10 GeV, based on data collected by the EGRET instrument on the Compton Gamma Ray Observatory. Although the maps can be used for a variety of applications. the immediate goal is the generation of diffuse gamma-ray maps which can be used as a diffuse background/foreground for point source analysis of the data to be obtained from new high-energy gamma-ray missions like GLAST and AGILE. To generate the diffuse gamma maps from the raw EGRET maps, the point sources in the Third EGRET Catalog were subtracted out using the appropriate point spread function for each energy range. After that, smoothing was performed to minimize the effects of photon statistical noise. A smoothing length of 1 deg vas used for the Galactic plane maps. For the all-sky maps, a procedure was used which resulted in a smoothing length roughly equivalent to 4 deg. The result of this work is 16 maps of different energy intervals for absolute value of b < or equal to 20 deg, and 32 all-sky maps, 16 in equatorial coordinates (J2000) and 16 in Galactic coordinates.

  20. EGRET Diffuse Gamma Ray Maps Between 30 MeV and 10 GeV

    NASA Technical Reports Server (NTRS)

    Cillis, A. N.; Hartman, R. C.

    2004-01-01

    This paper presents all-sky maps of diffuse gamma radiation in various energy ranges between 30 MeV and 10 GeV, based on data collected by the EGRET instrument on the Compton Gamma Ray Observatory. Although the maps can be used for a variety of applications, the immediate goal is the generation of diffuse gamma-ray maps which can be used as a diffuse background/foreground for point source analysis of the data to be obtained from new high-energy gamma-ray missions like GLAST and AGILE. To generate the diffuse gamma maps from the raw EGRET maps, the point sources in the Third EGRET Catalog were subtracted out using the appropriate point spread function for each energy range. After that, smoothing was performed to minimize the effects of photon statistical noise. A smoothing length of 1deg was used for the Galactic plane maps. For the all-sky maps, a procedure was used which resulted in a smoothing length roughly equivalent to 4deg. The result of this work is 16 maps of different energy intervals for [b]less than or equal to 20deg, and 32 all-sky maps, 16 in equatorial coordinates (J2000) and 16 in Galactic coordinates.

  1. Suzaku Observations of Extreme MeV Blazar Swift J0746.3+2548

    SciTech Connect

    Watanabe, Shin; Sato, Rie; Takahashi, Tadayuki; Kataoka, Jun; Madejski, Greg; Sikora, Marek; Tavecchio, Fabrizio; Sambruna, Rita; Romani, Roger; Edwards, Philip G.; Pursimo, Tapio

    2008-12-01

    We report the Suzaku observations of the high luminosity blazar SWIFT J0746.3+2548 (J0746) conducted in November 2005. This object, with z = 2.979, is the highest redshift source observed in the Suzaku Guaranteed Time Observer (GTO) period, is likely to show high gamma-ray flux peaking in the MeV range. As a result of the good photon statistics and high signal-to-noise ratio spectrum, the Suzaku observation clearly confirms that J0746 has an extremely hard spectrum in the energy range of 0.3-24 keV, which is well represented by a single power-law with a photon index of {Lambda}{sub ph} {approx_equal} 1.17 and Galactic absorption. The multiwavelength spectral energy distribution of J0746 shows two continuum components, and is well modeled assuming that the high-energy spectral component results from Comptonization of the broad-line region photons. In this paper we search for the bulk Compton spectral features predicted to be produced in the soft X-ray band by scattering external optical/UV photons by cold electrons in a relativistic jet. We discuss and provide constraints on the pair content resulting from the apparent absence of such features.

  2. Compton-Pair Production Space Telescope: Extending Fermi-LAT Discoveries into MeV Gamma-ray Astronomy

    NASA Astrophysics Data System (ADS)

    Smith, Andrew; ComPair Team

    2016-03-01

    The keV-MeV gamma-ray energy range has remained largely unexplored over the last decade despite offering an exciting window into many astrophysical questions. This energy range is particularly challenging because it is firmly in the Compton-dominated regime where the interaction cross section is minimized. We are developing a MIDEX-scale wide-aperture discovery mission, Compton-Pair Production Space Telescope (ComPair), to investigate the energy range from 200 keV to >500 MeV with good energy and angular resolution and with sensitivity approaching a factor of 20-50 better than previous instruments. ComPair will build on the heritage of successful space missions including Fermi-LAT, AGILE, AMS and PAMELA, and will use well-developed space-qualified detector technologies including Si-strip and CdZnTe-strip detectors, heavy inorganic scintillators, and plastic scintillators. on behalf of the ComPair Team.

  3. 80 MeV C6+ ion irradiation effects on the DC electrical characteristics of silicon NPN power transistors

    NASA Astrophysics Data System (ADS)

    Bharathi, M. N.; Pushpa, N.; Vinayakprasanna, N. H.; Prakash, A. P. Gnana

    2016-05-01

    The total dose effects of 80 MeV C6+ ions on the DC electrical characteristics of Silicon NPN rf power transistors have been studied in the dose range of 100 krad to 100 Mrad. The SRIM simulation was used to understand the energy loss and range of the ions in the transistor structure. The different electrical parameters such as Gummel characteristics, excess base current (ΔIB = IBpost - IBpre), dc forward current gain (hFE), transconductance (gm), displacement damage factor (K) and output characteristics (VCE-IC) were studied systematically before and after irradiation. The significant degradation in base current (IB) and hFE was observed after irradiation. Isochronal annealing study was conducted on the irradiated transistors to analyze the recovery in different electrical parameters. These results were compared with 60C0 gamma irradiation results in the same dose range.

  4. The thermoluminescence characteristics and the glow curves of Thulium doped silica fiber exposed to 10MV photon and 21MeV electron radiation.

    PubMed

    Alawiah, A; Alina, M S; Bauk, S; Abdul-Rashid, H A; Gieszczyk, W; Noramaliza, M N; Mahdiraji, G A; Tamchek, N; Zulkifli, M I; Bradley, D A; Marashdeh, M W

    2015-04-01

    The thermoluminescence (TL) glow curves and kinetics parameters of Thulium (Tm) doped silica cylindrical fibers (CF) are presented. A linear accelerator (LINAC) was used to deliver high-energy radiation of 21MeV electrons and 10MV photons. The CFs were irradiated in the dose range of 0.2-10Gy. The experimental glow curve data was reconstructed by using WinREMS. The WinGCF software was used for the kinetic parameters evaluation. The TL sensitivity of Tm-doped silica CF is about 2 times higher as compared to pure silica CF. Tm-doped silica CF seems to be more sensitive to 21MeV electrons than to 10MV photons. Surprisingly, no supralinearity was displayed and a sub-linear response of Tm-doped silica CF was observed within the analyzed dose range for both 21MeV electrons and 10MV photons. The Tm-doped silica CF glow curve consists of 5 individual glow peaks. The Ea of peak 4 and peak 5 was highly dependent on dose when irradiated with photons. We also noticed that the electron radiation (21MeV) caused a shift of glow peak by 7-13°C to the higher temperature region compared with photons radiation (10MV). Our Tm-doped fibers seem to give high TL response after 21MeV electrons, which gives around 2 times higher peak integral as compared with 10MV photon radiation. We concluded that peak 4 is the first-order kinetic peak and can be used as the main dosimetric peak of Tm-doped silica CF.

  5. Experimental evaluation of the response of micro-channel plate detector to ions with 10s of MeV energies

    NASA Astrophysics Data System (ADS)

    Jeong, Tae Won; Singh, P. K.; Scullion, C.; Ahmed, H.; Kakolee, K. F.; Hadjisolomou, P.; Alejo, A.; Kar, S.; Borghesi, M.; Ter-Avetisyan, S.

    2016-08-01

    The absolute calibration of a microchannel plate (MCP) assembly using a Thomson spectrometer for laser-driven ion beams is described. In order to obtain the response of the whole detection system to the particles' impact, a slotted solid state nuclear track detector (CR-39) was installed in front of the MCP to record the ions simultaneously on both detectors. The response of the MCP (counts/particles) was measured for 5-58 MeV carbon ions and for protons in the energy range 2-17.3 MeV. The response of the MCP detector is non-trivial when the stopping range of particles becomes larger than the thickness of the detector. Protons with energies E ≳ 10 MeV are energetic enough that they can pass through the MCP detector. Quantitative analysis of the pits formed in CR-39 and the signal generated in the MCP allowed to determine the MCP response to particles in this energy range. Moreover, a theoretical model allows to predict the response of MCP at even higher proton energies. This suggests that in this regime the MCP response is a slowly decreasing function of energy, consistently with the decrease of the deposited energy. These calibration data will enable particle spectra to be obtained in absolute terms over a broad energy range.

  6. Experimental evaluation of the response of micro-channel plate detector to ions with 10s of MeV energies.

    PubMed

    Jeong, Tae Won; Singh, P K; Scullion, C; Ahmed, H; Kakolee, K F; Hadjisolomou, P; Alejo, A; Kar, S; Borghesi, M; Ter-Avetisyan, S

    2016-08-01

    The absolute calibration of a microchannel plate (MCP) assembly using a Thomson spectrometer for laser-driven ion beams is described. In order to obtain the response of the whole detection system to the particles' impact, a slotted solid state nuclear track detector (CR-39) was installed in front of the MCP to record the ions simultaneously on both detectors. The response of the MCP (counts/particles) was measured for 5-58 MeV carbon ions and for protons in the energy range 2-17.3 MeV. The response of the MCP detector is non-trivial when the stopping range of particles becomes larger than the thickness of the detector. Protons with energies E ≳ 10 MeV are energetic enough that they can pass through the MCP detector. Quantitative analysis of the pits formed in CR-39 and the signal generated in the MCP allowed to determine the MCP response to particles in this energy range. Moreover, a theoretical model allows to predict the response of MCP at even higher proton energies. This suggests that in this regime the MCP response is a slowly decreasing function of energy, consistently with the decrease of the deposited energy. These calibration data will enable particle spectra to be obtained in absolute terms over a broad energy range.

  7. Experimental evaluation of the response of micro-channel plate detector to ions with 10s of MeV energies.

    PubMed

    Jeong, Tae Won; Singh, P K; Scullion, C; Ahmed, H; Kakolee, K F; Hadjisolomou, P; Alejo, A; Kar, S; Borghesi, M; Ter-Avetisyan, S

    2016-08-01

    The absolute calibration of a microchannel plate (MCP) assembly using a Thomson spectrometer for laser-driven ion beams is described. In order to obtain the response of the whole detection system to the particles' impact, a slotted solid state nuclear track detector (CR-39) was installed in front of the MCP to record the ions simultaneously on both detectors. The response of the MCP (counts/particles) was measured for 5-58 MeV carbon ions and for protons in the energy range 2-17.3 MeV. The response of the MCP detector is non-trivial when the stopping range of particles becomes larger than the thickness of the detector. Protons with energies E ≳ 10 MeV are energetic enough that they can pass through the MCP detector. Quantitative analysis of the pits formed in CR-39 and the signal generated in the MCP allowed to determine the MCP response to particles in this energy range. Moreover, a theoretical model allows to predict the response of MCP at even higher proton energies. This suggests that in this regime the MCP response is a slowly decreasing function of energy, consistently with the decrease of the deposited energy. These calibration data will enable particle spectra to be obtained in absolute terms over a broad energy range. PMID:27587107

  8. Accuracy evaluation of a Compton X-ray spectrometer with bremsstrahlung X-rays generated by a 6 MeV electron buncha)

    NASA Astrophysics Data System (ADS)

    Kojima, Sadaoki; Arikawa, Yasunobu; Nishimura, Yasuhiko; Togawa, Hiromi; Zhang, Zhe; Ikenouchi, Takahito; Ozaki, Tetsuo; Morace, Alessio; Nagai, Takahiro; Abe, Yuki; Sakata, Shouhei; Inoue, Hiroaki; Utsugi, Masaru; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Kato, Ryukou; Fujioka, Shinsuke; Azechi, Hiroshi

    2014-11-01

    A Compton-scattering-based X-ray spectrometer is developed to obtain the energy distribution of fast electrons produced by intense laser and matter interactions. Bremsstrahlung X-rays generated by fast electrons in a material are used to measure fast electrons' energy distribution in matter. In the Compton X-ray spectrometer, X-rays are converted into recoil electrons by Compton scattering in a converter made from fused silica glass, and a magnet-based electron energy analyzer is used to measure the energy distribution of the electrons that recoil in the direction of the incident X-rays. The spectrum of the incident X-rays is reconstructed from the energy distribution of the recoil electrons. The accuracy of this spectrometer is evaluated using a quasi-monoenergetic 6 MeV electron bunch that emanates from a linear accelerator. An electron bunch is injected into a 1.5 mm thick tungsten plate to produce bremsstrahlung X-rays. The spectrum of these bremsstrahlung X-rays is obtained in the range from 1 to 9 MeV. The energy of the electrons in the bunch is estimated using a Monte Carlo simulation of particle-matter interactions. The result shows that the spectrometer's energy accuracy is ±0.5 MeV for 6.0 MeV electrons.

  9. Accuracy evaluation of a Compton X-ray spectrometer with bremsstrahlung X-rays generated by a 6 MeV electron bunch

    SciTech Connect

    Kojima, Sadaoki Arikawa, Yasunobu; Zhang, Zhe; Ikenouchi, Takahito; Morace, Alessio; Nagai, Takahiro; Abe, Yuki; Sakata, Shouhei; Inoue, Hiroaki; Utsugi, Masaru; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Fujioka, Shinsuke; Azechi, Hiroshi; Nishimura, Yasuhiko; Togawa, Hiromi; Ozaki, Tetsuo; Kato, Ryukou

    2014-11-15

    A Compton-scattering-based X-ray spectrometer is developed to obtain the energy distribution of fast electrons produced by intense laser and matter interactions. Bremsstrahlung X-rays generated by fast electrons in a material are used to measure fast electrons’ energy distribution in matter. In the Compton X-ray spectrometer, X-rays are converted into recoil electrons by Compton scattering in a converter made from fused silica glass, and a magnet-based electron energy analyzer is used to measure the energy distribution of the electrons that recoil in the direction of the incident X-rays. The spectrum of the incident X-rays is reconstructed from the energy distribution of the recoil electrons. The accuracy of this spectrometer is evaluated using a quasi-monoenergetic 6 MeV electron bunch that emanates from a linear accelerator. An electron bunch is injected into a 1.5 mm thick tungsten plate to produce bremsstrahlung X-rays. The spectrum of these bremsstrahlung X-rays is obtained in the range from 1 to 9 MeV. The energy of the electrons in the bunch is estimated using a Monte Carlo simulation of particle-matter interactions. The result shows that the spectrometer's energy accuracy is ±0.5 MeV for 6.0 MeV electrons.

  10. Origin of the MeV energy nucleon flux associated with CIRs

    SciTech Connect

    Christon, S.P.

    1981-10-01

    Measurements of recurrent enhancements of interplanetary nucleon flux in the MeV energy range, detected at widely separated points in the heliosphere by charged particle instruments on board the Pioneer 10 and 11, IMP 7 and 8, and Mariner 10 spacecraft, are presented and interpreted. These features recur at the solar rotation period in association with stream-stream plasma interaction regions corotating with the sun (CIRs) and are not directly produced by solar flaring activity. At distances from the sun r<1 AU, the maximum intensities of the hydrogen (H) and helium (He) components in these flux enhancements increase with increasing r at the same rate, usually between 300 %/AU and 600 %/AU. The nucleon abundance ratio H/He and the slopes of H and He differential energy spectra are relatively constant with r. One of the models proposed to explain these enhanced fluxes predicts the acceleration of nuclei from keV plasma energies to MeV energies via the transit time damping of magnetosonic waves as solar wind plasma flows from the sun. The predicted acceleration rates of H and He different in this model. We compute numerical solutions of the transport equation to show that this model does not reproduce the radial variations of the H and He fluxes observed with nearly identical University of Chicago instruments. Flux associated with one of the relatively rare CIR shocks at 1 AU is shown to be similar to the flux in other corotating enhancements. Direct estimates of the radial diffusive mean free path lambda/sub r/ ranging from 0.03 AU to 0.11 AU, are evaluated by using the sunward diffusive anisotropies obtained at 1 AU and the simultaneous increase of intensity with r. These values of lambda/sub r/ are consistent with those derived in studies of solar flare related particle flux and other corotating nucleon flux enhancements at higher rigidities. The observations are consistent with nucleon acceleration at the CIR shocks beyond 1 AU with subsequent diffusion inward.

  11. Phase shift analysis of all proton-proton scattering data below T sub lab =350 MeV

    SciTech Connect

    Bergervoet, J.R.; Campen, P.C. van; Klomp, R.A.M.; Kok, J. de; Rijken, T.A.; Stoks, V.G.J.; Swart, J.J. de )

    1990-04-01

    As a continuation of our 0--30 MeV analysis we present a multienergy phase shift analysis of all {ital pp} scattering data below {ital T}{sub lab}=350 MeV. In the description of all partial waves we take exactly into account the long-range potential consisting of the improved Coulomb potential (including the magnetic moment interaction), the vacuum polarization potential, and the tail of the one-pion-exchange potential. To describe the short-range interaction in the lower partial waves we use a {ital P}-matrix parametrization. The intermediate partial waves are treated either by optimal mapping techniques or by using the Nijmegen soft-core potential. The latter gives a better description of the data. The final data set comprises 1626 scattering observables. The best fit to this final data set results in {chi}{sup 2}/{ital N}{sub df}=1.117, where {ital N}{sub df}=1576 is the number of degrees of freedom. The {ital pp}{pi}{sup 0} pseudovector coupling constant is determined to be {ital f}{sub 0}{sup 2}=(74.9{plus minus}0.7){times}10{sup {minus}3}. Single-energy phase shifts and errors are also given.

  12. Cross-section for proton tritium scattering from 1.4 to 3.4 MeV at the laboratory angle of 165°

    NASA Astrophysics Data System (ADS)

    Xia, X. J.; Ding, W.; Zhang, B.; Long, X. G.; Luo, S. Z.; Peng, S. M.; Hutton, R.; Shi, L. Q.

    2008-03-01

    The elastic scattering cross-section for proton scattering from tritium was measured at a laboratory angle of 165° and over an incident proton energy range from 1.4 to 3.4 MeV. A thin solid target containing 1.62 × 1017 T atoms/cm2 was prepared by absorption of tritium into a film of titanium on aluminium foil backing. The cross-section increases almost linearly with decreasing energy in the higher energy region of 2-3.4 MeV. The currently measured cross-section data are compared with data available in the literature values and they show a similarly linear trend in a similar higher energy range. The maximum difference in the cross-section at almost the same scattering angle between current data and the previous results is no worse than 2.3%.

  13. Absolute calibration of photostimulable image plate detectors used as (0.5-20 MeV) high-energy proton detectors.

    PubMed

    Mancić, A; Fuchs, J; Antici, P; Gaillard, S A; Audebert, P

    2008-07-01

    In this paper, the absolute calibration of photostimulable image plates (IPs) used as proton detectors is presented. The calibration is performed in a wide range of proton energies (0.5-20 MeV) by exposing simultaneously the IP and calibrated detectors (radiochromic films and solid state detector CR39) to a source of broadband laser-accelerated protons, which are spectrally resolved. The final result is a calibration curve that enables retrieving the proton number from the IP signal. PMID:18681694

  14. Comparison of the vector analyzing power iT sub 11 for. pi. sup + d scattering at 180 MeV

    SciTech Connect

    Tacik, R.; Boschitz, E.T.; Gyles, W.; Wessler, M. Institut fuer Kernphysik and Institut fuer Experimentelle Kernphysik der Universitaet Karlsruhe ); Mango, S.; van den Brandt, B.; Konter, J.A. ); Gill, D.R.; Weber, P. )

    1990-11-01

    The vector analyzing power {ital iT}{sub 11} has been measured for the first time for {pi}{sup +}{ital d} and {pi}{sup {minus}}{ital d} elastic scattering at {ital T}{sub {pi}}=180 MeV in the angular range between 50{degree} and 110{degree}, using a polarized deuteron target and a magnetic spectrometer. The data are compared with theoretical calculations involving different Coulomb prescriptions.

  15. Angular distribution of 4.43-MeV γ-rays produced in inelastic scattering of 14.1-MeV neutrons by 12C nuclei

    NASA Astrophysics Data System (ADS)

    Bystritsky, V. M.; Grozdanov, D. N.; Zontikov, A. O.; Kopach, Yu. N.; Rogov, Yu. N.; Ruskov, I. N.; Sadovsky, A. B.; Skoy, V. R.; Barmakov, Yu. N.; Bogolyubov, E. P.; Ryzhkov, V. I.; Yurkov, D. I.

    2016-07-01

    The work is devoted to measuring the angular distribution of 4.43-MeV γ-rays produced in inelastic scattering of 14.1-MeV neutrons by 12C nuclei. A portable ING-27 neutron generator (designed and fabricated at VNIIA, Moscow) with a built-in 64-pixel silicon α-detector was used as a source of tagged neutrons. The γ-rays of characteristic nuclear radiation from 12C were detected with a spectrometric system that consisted of 22 γ-detectors based on NaI(Tl) crystals arranged around the carbon target. The measured angular distribution of 4.43-MeV γ-rays is analyzed and compared with the results of other published experimental works.

  16. 76Se(t,p)78Se reaction at 17 MeV

    NASA Astrophysics Data System (ADS)

    Watson, D. L.; Fortune, H. T.

    1987-02-01

    The 76Se(t,p)78Se reaction has been studied at an incident energy of 17 MeV. Excitation energies for 80 states (or groups of states) up to 6.16 MeV have been measured. Angular distributions have been obtained for 61 of them, below Ex=5.03 MeV. Comparison of the data with distorted-wave Born approximation calculations, using pure configurations for the transfer amplitudes, have enabled the L transfer (and hence Jπ value) to be determined for 58 of these states. Of these assignments, 52 are new.

  17. The reaction proton deuteron yields triton pion at 470 and 590 MeV

    NASA Technical Reports Server (NTRS)

    Dollhopf, W.; Lunke, C.; Perdrisat, C. F.; Roberts, W. K.; Kitching, P.; Olsen, W. C.; Priest, J. R.

    1973-01-01

    The preliminary results from a study of the deuteron (proton, positive pion)triton reaction are reported. The differential cross section for this reaction was measured for a number of center of mass angles from 37 deg to 160 deg at incident proton energies of 470 and 590 MeV. The cross sections measured at 590 MeV agree with predictions made considering a two-nucleon process. The 470 MeV data shows a peak in the backward direction which is not predicted by this mechanism.

  18. A Compton scatter camera for spectral imaging of 0.5 to 3.0 MeV gamma rays

    SciTech Connect

    Martin, J.B.

    1994-12-31

    A prototype Compton scatter camera for imaging gamma rays has been built and tested. This camera addresses unique aspects of gamma-ray imaging at nuclear industrial sites, including gamma-ray energies in the 0.5 to 3.0 MeV range and polychromatic fields. Analytic models of camera efficiency, resolution and contaminating events are developed. The response of the camera bears strong similarity to emission computed tomography devices used in nuclear medicine. A direct Fourier based algorithm is developed to reconstruct two-dimensional images of measured gamma-ray fields. Iterative ART and MLE algorithms are also investigated. The point response of the camera to gamma rays of energies from 0.5 to 2.8 MeV is measured and compared to the analytic models. The direct reconstruction algorithm is at least ten times more efficient than the iterative algorithms are also investigated. The point response of the camera to gamma rays energies from 0.5 to 2.8 MeV is measured and compared to the analytic models. The direct reconstruction algorithm is at least ten times more efficient than the iterative algorithms and produces images that are, in general, of the same quality. Measured images of several phantoms are shown. Important results include angular resolutions as low as 4.4{degrees}, reproduction of phantom size and position within 7%, and contrast recovery of 84% or better. Spectral imaging is demonstrated with independent images from a multi-energy phantom consisting of two sources imaged simultaneously.

  19. Study on strontium isotope abundance-ratio measurements by using a 13-MeV proton beam

    NASA Astrophysics Data System (ADS)

    Jeong, Cheol-Ki; Jang, Han; Lee, Goung-Jin

    2016-09-01

    The Rb-Sr dating method is used in dating Paleozoic and Precambrian rocks. This method measures the 87Rb and the 87Sr concentrations by using thermal ionization mass spectrometry (TIMS) [J. Hefne et al., Inter. J. Phys. Sci. 3(1), 28 (2008)]. In addition, it calculates the initial 87Sr/86Sr ratio to increase the reliability of Rb-Sr dating. In this study, the 87Sr/86Sr ratio was measured by using a 13-MeV proton accelerator. Proton kinetic energies are in the range of tens of megaelectronvolts, and protons have large absorption cross-sections for ( p, n) reactions with most substances. After absorbing a proton with such a high kinetic energy, an element is converted into a nuclide with its atomic number increased by one via nuclear transmutation. These nuclides usually have short half-lives and return to the original state through radioactive decay. When a strontium sample is irradiated with protons, nuclear transmutation occurs; thus, the strontium isotope present in the sample changes to a yttrium isotope, which is an activated radioisotope. Based on this, the 87Sr/86Sr ratio was calculated by analyzing the gamma-rays emitted by each yttrium isotope. The KIRAMS-13 cyclotron at the Cyclotron Center of Chosun University, where 13-MeV protons can be extracted, was utilized in our experiment. The 87Sr/86Sr isotope ratio was computed for samples irradiated with these protons, and the result was similar to the isotope ratio for the Standard Reference Material, i.e., 98.2 ± 3.4%. As part of the analysis, proton activation analyses were performed using 13-MeV protons, and the experimental results of this research suggest a possible approach for measuring the strontium-isotope abundance ratio of samples.

  20. Accurate measurements of the collision stopping powers for 5 to 30 MeV electrons

    NASA Astrophysics Data System (ADS)

    MacPherson, Miller Shawn

    Accurate knowledge of electron stopping powers is crucial for accurate radiation dosimetry and radiation transport calculations. Current values for stopping powers are based on a theoretical model, with estimated uncertainties of 0.5-1% (1σ) for electron energies greater than 100 keV. This work presents the first measurements of electron collision stopping powers capable of testing the theoretical values within these stated uncertainties. A large NaI spectrometer was used to measure the change in electron energy when an absorbing disk of known thickness was placed in an electron beam. Monte Carlo simulations of the experiment were performed to account for the effects of surrounding materials. Energy differences between the calculated and measured spectra were used to determine corrections to the soft collision component of the theoretical stopping powers employed by the Monte Carlo simulations. Four different elemental materials were studied: Be, Al, Cu, and Ta. This provided a wide range of atomic numbers and densities over which to test the theory. In addition, stopping powers were measured for graphite (both standard and pyrolytic), A-150 tissue equivalent plastic, C-552 air equivalent plastic, and water. The incident electron energies ranged from 5 to 30 MeV. Generally, the measured stopping powers agree with the theoretical values within the experimental uncertainties, which range from 0.4% to 0.7% (1σ). Aluminum, however, exhibits a 0.7% discrepancy at higher electron energies. Furthermore, these measurements have established that the grain density stopping power is appropriate for graphite, contrary to the recommendations of ICRU Report 37. This removes a 0.2% uncertainty in air kerma calibrations, and impacts on dosimetric quantities determined via graphite calorimetry, such as ɛG for Fricke dosimetry and (W/ e)air for ion chamber measurements.

  1. Comparison of bactericidal efficiency of 7.5 MeV X-rays, gamma-rays, and 10 MeV e-beams

    NASA Astrophysics Data System (ADS)

    Song, Beom-Seok; Lee, Yunjong; Moon, Byeong-Geum; Go, Seon-Min; Park, Jong-Heum; Kim, Jae-Kyung; Jung, Koo; Kim, Dong-Ho; Ryu, Sang-Ryeol

    2016-08-01

    This study was performed to verify the feasibility of 7.5 MeV X-rays for food pasteurization through a comparison of the bactericidal efficiency with those of other sources for selected bacterial pathogens. No significant differences were observed between the overall bactericidal efficiency for beef-inoculated pathogens based on the uncertainty of the absorbed dose and variations in bacterial counts. This result supported that all three irradiation sources were effective for inactivation of food-borne bacteria and that 7.5 MeV X-rays may be used for food pasteurization.

  2. Absolute Calibration of Image Plate for electrons at energy between 100 keV and 4 MeV

    SciTech Connect

    Chen, H; Back, N L; Eder, D C; Ping, Y; Song, P M; Throop, A

    2007-12-10

    The authors measured the absolute response of image plate (Fuji BAS SR2040) for electrons at energies between 100 keV to 4 MeV using an electron spectrometer. The electron source was produced from a short pulse laser irradiated on the solid density targets. This paper presents the calibration results of image plate Photon Stimulated Luminescence PSL per electrons at this energy range. The Monte Carlo radiation transport code MCNPX results are also presented for three representative incident angles onto the image plates and corresponding electron energies depositions at these angles. These provide a complete set of tools that allows extraction of the absolute calibration to other spectrometer setting at this electron energy range.

  3. Radiation damage induced in Al2O3 single crystal by 90 MeV Xe ions

    NASA Astrophysics Data System (ADS)

    Zirour, H.; Izerrouken, M.; Sari, A.

    2015-12-01

    Radiation damage induced in Al2O3 single crystal by 90 MeV Xe ions were investigated by optical absorption measurements, Raman spectroscopy and X-ray diffraction (XRD) techniques. The irradiations were performed at the GANIL accelerator in Caen, France for the fluence in the range from 1012 to 6 × 1013 cm-2 at room temperature under normal incidence. The F+ and F22+ centers kinetic as a function of fluence deduced from the optical measurements explains that the single defects (F and F+) aggregate to F center clusters (F2 , F2+, F22+) during irradiation at high fluence (>1013 cm-2). Raman and XRD analysis reveal a partial disorder of 40% of Al2O3 in the studied fluence range in accordance with Kabir et al. (2008) study. The result suggests that this is due to the stress relaxation process which occurs at high fluence (>1013 cm-2).

  4. Fractionated dose of 35-MEV fast neutrons and hypoxic tumor cell survival curve.

    PubMed

    U, R; Evans, J C; Cavanaugh, P J; Abramson, N; Thompson, T T; Wheless, D M

    1975-06-01

    The determination of the RBE for the MANTA fast neutrons produced by NRL is inprogress, with the model system using tumor cell population kinetic response patterns assayed in vitro after irradiation in vivo. Ascites tumor cells BW-5147 were irradiated with a clinically usable fast neutron beam from the NRL cyclotron, which is produced by accelrating deuterons to 35 MeV and using htem to bombard a thick berylliumtarget. The comparison of dose-effect relationships was made for doses ranging from30 to 1000 rads. The doses required for an isoeffect on BW-5147 hypoxic tumor cell survival and impairment of its reproductive capacity from fast neutron exposure were not different wheither it was given a single dose or the same dose given in three fractions separated by long recovery periods in situ. No intracellular repair of sublethal injury when the dose was given in three fractions, although the hypoxic BWp5147 tumor cells haveno effective reoxygenation or repopulation in this time interval. The RBE for the fast neutron beam is 4 relative to x rays for fractionated doses at the surviving fractionlevel of 0.6-0.7, while the RBE IS 2.5 FOR SINGLE DOSES. However, at a surviving fraction of 0.1, the RBE is 1.9 for single and 2.8 for fractionated doses. Analysis of thedaily cell population rate or mitotic delay between the two types of radiations at a similiar level of survival.

  5. Testing a prototype BGO calorimeter with 100-800 MeV positron beams

    NASA Astrophysics Data System (ADS)

    Ishikawa, T.; Fujimura, H.; Grigoriev, D. N.; Hashimoto, R.; Kaida, S.; Kitazawa, R.; Kuznetsov, G. N.; Nakamura, A.; Shimizu, H.; Suzuki, K.; Takahashi, S.; Tsuchikawa, Y.; Vasiliev, Ya. V.; Yamazaki, H.

    2016-11-01

    An electromagnetic calorimeter, BGOegg, composed of 1320 BGO crystals, has been constructed at the Research Center for Electron Photon Science, Tohoku University to study the structure of hadrons in detail using photo-induced reactions. The design of the new electromagnetic calorimeter and the basic characteristics of the manufactured BGO crystals are described. A performance test has been conducted for the prototype, which consists of 25 crystals arranged in a 5×5 matrix, using positron beams at energies ranging from 100 to 800 MeV. The obtained energy resolution is (σE / E) 2 =(0.63 %) 2 +(1.15 % ± 0.04 %) 2 /(E / GeV) +(0.42 % ± 0.03 %) 2 /(E / GeV) 2 at room temperature. The energy resolution corresponds to 1.38 % ± 0.05 % for 1-GeV positrons. The position resolution is found to be σr / mm =(3.07 ± 0.03)(E / GeV) - 0.202 ± 0.008 which corresponds to an angular resolution of approximately 1 ° for 1-GeV positrons.

  6. Electric-field-induced electron detachment of 800-MeV H{sup {minus}} ions

    SciTech Connect

    Keating, P.B.; Gulley, M.S.; Bryant, H.C.; MacKerrow, E.P.; Miller, W.A.; Rislove, D.C.; Cohen, S.; Donahue, J.B.; Fitzgerald, D.H.; Funk, D.J.; Frankle, S.C.; Hutson, R.L.; Macek, R.J.; Plum, M.A.; Stanciu, N.G.; van Dyck, O.B.; Wilkinson, C.A.

    1995-12-01

    The lifetime of 800-MeV H{sup {minus}} ions against electron detachment in a static electric field was measured over a range of eight orders of magnitude in experiments at the High Resolution Atomic Beam Facility of the Los Alamos Meson Physics Facility. The ions traversed a linear gradient magnetic field of 1.3-T peak strength resulting in a 6-MV/cm peak rest-frame electric field capable of stripping a large fraction of H{sup {minus}} ions. The unstripped H{sup {minus}} ions, neutral H{sup 0} atoms, and protons were detected 5.5 m from the magnet. This spectrum was analyzed to determine the lifetime of the H{sup {minus}} ion versus electric-field strength and the results were compared with previous studies. Three parametrizations of the lifetime formula based on an existing theory were used to calculate the stripping probability. The data were fit to the lifetime formula and good agreement with theoretical predictions was found. Finally, a possible experiment for observing excited states of H{sup {minus}} is briefly discussed.

  7. Positron probing of phosphorus-vacancy complexes in silicon irradiated with 15 MeV protons

    NASA Astrophysics Data System (ADS)

    Arutyunov, N.; Emtsev, V.; Krause-Rehberg, R.; Elsayed, M.; Kessler, C.; Kozlovski, V.; Oganesyan, G.

    2015-06-01

    Defects in phosphorus-doped silicon samples of floating-zone material, n-FZ-Si(P), produced under irradiation with 15 MeV protons at room temperature are studied by positron annihilation lifetime spectroscopy over the temperature range of ∼ 30 K - 300 K and by low- temperature Hall effect measurements. After annealing of E-centersand divacancies, we detected for the first time high concentrations of positron traps which had not been observed earlier. These defects are isochronally annealed over the temperature interval of ∼ 320 °C - 700 °C they manifest themselves as electrically neutral deep donor centersin the material of n-type. A long-lived component of the positron lifetime, τ2(I2 < 60%) ∼ 280 ps, attributed to these centers, suggests a relaxed configuration involving two vacancies. The enthalpy and entropy of annealing of these centersare Ea ∼ 1.05(0.21) eV and ΔSm ≈ 3.1(0.6)kB, respectively. It is argued that the microstructure of the defect consists of two vacancies, VV, and one atom of phosphorus, P. The split configuration of the VPV complex is shortly discussed.

  8. Photocatalytic activity of 6.5 MeV electron-irradiated ZnO nanorods

    NASA Astrophysics Data System (ADS)

    Sapnar, K. B.; Ghule, L. A.; Bhoraskar, S. V.; Garadkar, K. M.; Dhole, S. D.; Bhoraskar, V. N.

    2012-04-01

    The microwave-synthesized zinc-oxide (ZnO) nanonorods of average length of ∼ 1500 nm and diameter ∼ 100 nm were irradiated with 6.5 meV electrons. From sample to sample, the electron fluence was varied over the range 5×1014 to 2.5×1015 e-cm-2. The pre- and post-electron-irradiated ZnO nanorods were characterized by X-ray diffraction, UV-VIS, EDAX, scanning electron microscopy, transmission electron microscopy, and BET methods. The results show that after electron irradiation, the ZnO nanorods could retain the hexagonal phase with the wurtzite structure; however, the average length of the ZnO nanorods reduced to ∼ 800 nm. Moreover, the oxygen atoms from a fraction of ZnO molecules were dislodged, and the process contributed to the formation of Zn-ZnO mixed phase, with increased zinc to oxygen ratio. In the photo-degradation of Rhodamine-B, a significant enhancement in the photocatalytic activity of the electron-irradiated ZnO nanorods was observed. This could be attributed to the induced defects, reduced dimensions, and increased surface area of the ZnO nanorods, in addition to the formation of the Zn-ZnO phase. All these could collectively contribute to the effective separation of the photogenerated electrons from the holes on the ZnO nanorods, and therefore enhance the photocatalytic activity under UV exposure.

  9. A new study of 25Mg 28Si angular distributions at MeV

    NASA Astrophysics Data System (ADS)

    Caciolli, A.; Marchi, T.; Depalo, R.; Appannababu, S.; Blasi, N.; Broggini, C.; Cinausero, M.; Collazuol, G.; Degerlier, M.; Fabris, D.; Gramegna, F.; Leone, M.; Mastinu, P.; Menegazzo, R.; Montagnoli, G.; Rossi Alvarez, C.; Rigato, V.; Wieland, O.

    2014-09-01

    The observation of 26Al gives us the proof of active nucleosynthesis in the Milky Way. However the identification of the main producers of 26Al is still a matter of debate. Many sites have been proposed, but our poor knowledge of the nuclear processes involved introduces high uncertainties. In particular, the limited accuracy on the 25Mg 28Si reaction cross section has been identified as the main source of nuclear uncertainty in the production of 26Al in C/Ne explosive burning in massive stars, which has been suggested to be the main source of 26Al in the Galaxy. We studied this reaction through neutron spectroscopy at the CN Van de Graaff accelerator of the Legnaro National Laboratories. Thanks to this technique we are able to discriminate the events from possible contamination arising from parasitic reactions. In particular, we measured the neutron angular distributions at 5 different beam energies (between 3 and 5 MeV) in the - laboratory system angular range. The presented results disagree with the assumptions introduced in the analysis of a previous experiment.

  10. Characteristics of a normoxic polymethacrylic acid gel dosimeter for a 72-MeV proton beam

    NASA Astrophysics Data System (ADS)

    Bong, Jihye; Shin, Dongho; Kwon, Soo-Il

    2014-01-01

    The characteristics of a normoxic polymethacrylic acid gel dosimeter for a 72-MeV proton beam were evaluated. A polymer gel dosimeter was synthesized using gelatin, methacrylic acid, hydroquinone, tetrakis(hydroxymethyl) phosphonium chloride, and highly purified distilled water. The dosimeter was manufactured by placement in a polyethylene (PE) container. Irradiated dosimeters were analyzed to determine the transverse relaxation time (T2) using a 1.5-T MRI. A calibration curve was obtained as a function of the absorbed dose. A Bragg curve made by irradiating the gel with mono-energy was compared with the results for a parallel plate ionization chamber. The spread-out Bragg peak (SOBP) range and distal dose fall-off (DDF) were comparatively analyzed by comparing the irradiated gel with a spread-out Bragg peak against with the ion chamber. Lastly, the gel's usefulness as a dosimeter for therapeutic radiation quality assurance was evaluated by obtaining its practical field size, flatness, and symmetry, through comparison of the profiles of the gel and ion chamber.

  11. Vortex dynamics of 250 MeV Ag ions irradiated YBCO films

    NASA Astrophysics Data System (ADS)

    Khatua, Sanghamitra; Kumar, Ravi; Mishra, P. K.; Sahni, V. C.; Pinto, R.

    YBCO thin films with c-axis orientation were grown in-situ by KrF laser on LaAIO 3 substrate. The films were irradiated with 250 MeV Ag ions at doses equivalent to B φ ranging from 1 T to 4 T. Critical currents were measured using SQUID magnetometer with field parallel to columnar defects. There is a marked enhancement of vortice pinning due to generation of additional pinning centres. There seems to be an upper limit to the irradiation doses beyond which there is a 'smearing effect' on Jc. We also find a shift in Irreversibility Line towards higher field which is attributed to better pinning induced by columnar defects. Defect production is examined in the framework of "Coulomb explosion" model and the consequences are analysed in terms of defect-induced behaviour within the purview of models such as "Bean model", 'Exponential model' and "Vortex Glass" model. We point out that the 'stress model' provides a qualitative explanation for the reduced Tc and a broad transition at high fluence.

  12. MeV Gamma Ray Detection Algorithms for Stacked Silicon Detectors

    NASA Technical Reports Server (NTRS)

    McMurray, Robert E. Jr.; Hubbard, G. Scott; Wercinski, Paul F.; Keller, Robert G.

    1993-01-01

    By making use of the signature of a gamma ray event as it appears in N = 5 to 20 lithium-drifted silicon detectors and applying smart selection algorithms, gamma rays in the energy range of 1 to 8 MeV can be detected with good efficiency and selectivity. Examples of the types of algorithms used for different energy regions include the simple sum mode, the sum-coincidence mode used in segmented detectors, unique variations on sum-coincidence for an N-dimensional vector event, and a new and extremely useful mode for double escape peak spectroscopy at pair-production energies. The latter algorithm yields a spectrum similar to that of the pair spectrometer, but without the need of the dual external segments for double escape coincidence, and without the large loss in efficiency of double escape events. Background events due to Compton scattering are largely suppressed. Monte Carlo calculations were used to model the gamma ray interactions in the silicon, in order to enable testing of a wide array of different algorithms on the event N-vectors for a large-N stack.

  13. Design study for a 500 MeV proton synchrotron with CSNS linac as an injector

    NASA Astrophysics Data System (ADS)

    Huang, Liang-Sheng; Ji, Hong-Fei; Wang, Sheng

    2016-09-01

    Using the China Spallation Neutron Source (CSNS) linac as the injector, a 500 MeV proton synchrotron is proposed for multidisciplinary applications, such as biology, material science and proton therapy. The synchrotron will deliver proton beam with energy from 80 MeV to 500 MeV. A compact lattice design has been worked out, and all the important beam dynamics issues have been investigated. The 80 MeV H- beam is stripped and injected into the synchrotron by using multi-turn injection. In order to continuously extraction the proton with small beam loss, an achromatic structure is proposed and a slow extraction method with RF knock-out is adopted and optimized.

  14. Design study for a 500 MeV proton synchrotron with CSNS linac as an injector

    NASA Astrophysics Data System (ADS)

    Huang, Liang-Sheng; Ji, Hong-Fei; Wang, Sheng

    2016-09-01

    Using the China Spallation Neutron Source (CSNS) linac as the injector, a 500 MeV proton synchrotron is proposed for multidisciplinary applications, such as biology, material science and proton therapy. The synchrotron will deliver proton beam with energy from 80 MeV to 500 MeV. A compact lattice design has been worked out, and all the important beam dynamics issues have been investigated. The 80 MeV H‑ beam is stripped and injected into the synchrotron by using multi-turn injection. In order to continuously extraction the proton with small beam loss, an achromatic structure is proposed and a slow extraction method with RF knock-out is adopted and optimized.

  15. Observation of a 1750 MeV narrow meson decaying into ηη

    NASA Astrophysics Data System (ADS)

    Alde, D.; Binon, F.; Bricman, C.; Donskov, S. V.; Gouanère, M.; Inyakin, A. V.; Kachanov, V. A.; Kakauridze, D. B.; Khaustov, G. V.; Knapp, E. A.; Kulik, A. V.; Lagnaux, J. P.; Lednev, A. A.; Mikhailov, Yu. V.; Mouthuy, Th.; Peigneux, J. P.; Prokoshkin, Yu. D.; Rodnov, Yu. V.; Sadovsky, S. A.; Samoilenko, V. D.; Shagin, P. M.; Shtannikov, A. V.; Singovsky, A. V.; Stroot, J. P.; Sugonyaev, V. P.

    1986-12-01

    A narrow meson which decays into ηη is observed in 38 GeV/c π-p collisions at large momentum transfer. The experiment has been performed at the Serpukhov accelerator with the GAMS-2000 spectrometer. The mass of this new meson is (1755 +/- 8) MeV, its width is less than 50 MeV. Its spin-parity is JPC=0++ or less probably 2++.

  16. The alpha optical potential at 1,370 MeV

    NASA Astrophysics Data System (ADS)

    Bauhoff, W.

    1986-06-01

    Data for elastic scattering of alpha particles from12C and Ca-isotopes at 1,370 MeV are analyzed in terms of a phenomenological optical potential. No evidence is found for deviations of the real part from the usual Woods-Saxon shape, as it is the case for proton scattering at corresponding energies. A further increase in nuclear transparency is found compared to 700 MeV.

  17. Measurement and evaluation of selected 14-MeV neutron cross sections for fusion

    SciTech Connect

    Meadows, J.W.; Smith, D.L.; Cox, S.A.

    1985-01-01

    Experimental neutron-activation cross-section data in the vicinity of 14 MeV are evaluated for several reactions of fusion-related interest using a least-squares method. New experimental measurements are performed at 14.7 MeV for all of these considered reactions and for some commonly-used standard reactions as well. Comparison is made between measured and evaluated results.

  18. Production of α-particle emitting ²¹¹At using 45 MeV α-beam.

    PubMed

    Kim, Gyehong; Chun, Kwonsoo; Park, Sung Ho; Kim, Byungil

    2014-06-01

    Among the α-particle emitting radionuclides, (211)At is considered to be a promising radionuclide for targeted cancer therapy due to its decay properties. The range of alpha particles produced by the decay of (211)At are less than 70 µm in water with a linear energy transfer between 100 and 130 keV µm(-1), which are about the maximum relative biological effectiveness for heavy ions. It is important to note that at the present time, only a few of cyclotrons routinely produce (211)At. The direct production method is based on the nuclear reactions (209)Bi(α,2n)(211)At. Production of the radionuclide (211)At was carried out using the MC-50 cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). To ensure high beam current, the α-beam was extracted with an initial energy of 45 MeV, which was degraded to obtain the appropriate α-beam energy. The calculations of beam energy degradation were performed utilizing the MCNPX. Alumina-baked targets were prepared by heating the bismuth metal powder onto a circular cavity in a furnace. When using an E(α, av) of 29.17 MeV, the very small contribution of (210)At confirms the right choice of the irradiation energy to obtain a pure production of (211)At isotope. PMID:24819557

  19. Observation of the nuclear rainbow scattering for12C+12C at E Lab =300 MeV

    NASA Astrophysics Data System (ADS)

    Bohlen, H. G.; Clover, M. R.; Ingold, G.; Lettau, H.; von Oertzen, W.

    1982-06-01

    The elastic and inelastic scattering of12C on12C has been measured in the angular range between 2.8° and 70.4° in the c.m. system at E Lab =300 MeV. Optical model calculations have been performed with Woods-Saxon and folded potentials, the ground state and the first 2+-state were coupled in the calculations. The large cross sections of the elastic scattering at large angles is related to the nuclear rainbow scattering, which is centered at about 56°. This requires a potential depth of 100 MeV at a distance of 3 fm, the fit to the data is sensitive down to this region. The calculations with the folded potential show a better agreement with the data than those with the Woods-Saxon shape. The total reaction cross section of 1,420 mb, obtained from the optical model analysis, corresponds to the geometrical value; no transparency is observed.

  20. On the origin of the MeV energy nucleon flux associated with CIRs. [plasma interaction regions corotating with sun

    NASA Technical Reports Server (NTRS)

    Christon, S. P.

    1981-01-01

    Measurements of recurrent enhancements of interplanetary nucleon flux in the MeV energy range are presented and interpreted. The features recur at the solar rotation period in association with stream-stream plasma interaction regions corotating with the sun. At distances from the sun less than 1 AU, the maximum intensities of the hydrogen and helium components increase with increasing distance between 300%/AU and 600%/AU. A model is proposed which predicts the acceleration of nuclei from keV plasma energies to MeV energies by means of transit time damping of magnetosonic waves as solar wind plasma flows from the sun. Numerical solutions of the transport equation are derived to demonstrate that the model does not reproduce radial variations of hydrogen and helium fluxes, and estimates are made of the radial diffusive mean free path. Finally, the observations are found to be consistent with nucleon acceleration at the CIR shocks beyond 1 AU with subsequent diffusion toward the sun.

  1. Production of α-particle emitting ²¹¹At using 45 MeV α-beam.

    PubMed

    Kim, Gyehong; Chun, Kwonsoo; Park, Sung Ho; Kim, Byungil

    2014-06-01

    Among the α-particle emitting radionuclides, (211)At is considered to be a promising radionuclide for targeted cancer therapy due to its decay properties. The range of alpha particles produced by the decay of (211)At are less than 70 µm in water with a linear energy transfer between 100 and 130 keV µm(-1), which are about the maximum relative biological effectiveness for heavy ions. It is important to note that at the present time, only a few of cyclotrons routinely produce (211)At. The direct production method is based on the nuclear reactions (209)Bi(α,2n)(211)At. Production of the radionuclide (211)At was carried out using the MC-50 cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). To ensure high beam current, the α-beam was extracted with an initial energy of 45 MeV, which was degraded to obtain the appropriate α-beam energy. The calculations of beam energy degradation were performed utilizing the MCNPX. Alumina-baked targets were prepared by heating the bismuth metal powder onto a circular cavity in a furnace. When using an E(α, av) of 29.17 MeV, the very small contribution of (210)At confirms the right choice of the irradiation energy to obtain a pure production of (211)At isotope.

  2. Excitation function of the 60Ni(p ,γ )61Cu reaction from threshold to 16 MeV

    NASA Astrophysics Data System (ADS)

    Uddin, M. S.; Sudár, S.; Spahn, I.; Shariff, M. A.; Qaim, S. M.

    2016-04-01

    Excitation function of the reaction 60Ni(p ,γ )61Cu was measured via the activation technique in the energy range of 1.3-16.0 MeV using a low-energy accelerator and a small cyclotron. The results are comparable to those previously obtained via prompt γ counting. In addition excitation functions of the more common competing 60Ni(p ,n )60Cu and 60Ni(p ,α )57Co reactions were also measured. Theoretical calculations on proton-induced reactions on 60Ni were performed using the nuclear model code talys. The results suggest that near the threshold of the reaction the compound nucleus mechanism dominates. Thereafter the contribution of direct interactions becomes rather strong, especially between 4 and 6 MeV, i.e., just below the threshold of the 60Ni(p ,n )60Cu reaction. The cross section at the maximum of the excitation function of each of the three reactions, namely, 60Ni(p ,γ )61Cu,60Ni(p ,n )60Cu , and 60Ni(p ,α )57Co , amounts to 2, 320, and 85 mb, respectively. The (p ,n ) reaction is thus the most commonly occurring process, and the (p ,γ ) reaction is the weakest, possibly due to higher probability of particle emission than γ-ray emission from the highly excited intermediate nucleus 61Cu formed in the interaction of a proton with the target nucleus 60Ni.

  3. Evidence for the existence of the astrophysically important 6.40-MeV state of 31S

    NASA Astrophysics Data System (ADS)

    Irvine, D.; Chen, A. A.; Parikh, A.; Setoodehnia, K.; Faestermann, T.; Hertenberger, R.; Wirth, H.-F.; Bildstein, V.; Bishop, S.; Clark, J. A.; Deibel, C. M.; Hendriks, J.; Herlitzius, C.; Krücken, R.; Lennard, W. N.; Lepyoshkina, O.; Longland, R.; Rugel, G.; Seiler, D.; Straub, K.; Wrede, C.

    2013-11-01

    Proton-unbound excited states of 31S have been populated with the 32S(d,t)31S reaction at a beam energy of 24 MeV. Tritons corresponding to 31S states with Ex(31S)≈6.3-7.1 MeV were momentum analyzed with a high resolution quadrupole-dipole-dipole-dipole (Q3D) magnetic spectrograph at six angles ranging from θlab=15∘ to 58.5∘. We report a statistically significant detection of an astrophysically important state at Ex(31S)=6402 (2) keV, whose existence as a third state in this region has been under debate. Using updated A=31 nuclear structure information, we present a new set of proposed 31S-31P mirror assignments for 31S, in which this state is tentatively assigned a spin of 7/2. This level, corresponding to a 30P + p resonance at 271 keV, is likely to have a significant influence on the 30P(p,γ)31S reaction rate in explosive hydrogen burning in classical novae.

  4. Study of proton induced reactions on niobium targets up to 70 MeV

    NASA Astrophysics Data System (ADS)

    Ditrói, F.; Takács, S.; Tárkányi, F.; Baba, M.; Corniani, E.; Shubin, Yu. N.

    2008-12-01

    Niobium is a metal with important technological applications: use as alloying element to increase strength of super alloys, as thin layer for tribological applications, as superconductive material, in high temperature engineering systems, etc. In the frame of a systematic study of activation cross-sections of charged particle induced reactions on structural materials proton induced excitation functions on Nb targets were determined with the aim of applications in accelerator and reactor technology and for thin layer activation (TLA). The charged particle activation cross-sections on this element are also important for yield calculation of medical isotope production ( 88,89Zr, 86,87,88Y) and for dose estimation in PET targetry. As Niobium is a monoisotopic element it is an ideal target material to test nuclear reaction theories. We present here the integral excitation functions of 93Nb(p,x) 90,93mMo, 92m,91m,90Nb, 86,88,89Zr, 86,87mg,88Y and 85Sr in the energy range 30-70 MeV, some measured for the first time at this energy range. The results were compared with the theoretical cross-sections calculated by means of the code ALICE-IPPE and with the literature data. The calculations have been carried out without any parameter adjustment. The theory reproduces the shape of the measured results well and magnitude is also acceptable. Thick target yields calculated from our fitted cross-section give reliable estimations for production of medically relevant radioisotopes and for dose estimation in accelerator technology.

  5. An 800-MeV proton radiography facility for dynamic experiments

    NASA Astrophysics Data System (ADS)

    King, N. S. P.; Ables, E.; Adams, Ken; Alrick, K. R.; Amann, J. F.; Balzar, Stephen; Barnes, P. D., Jr.; Crow, M. L.; Cushing, S. B.; Eddleman, J. C.; Fife, T. T.; Flores, Paul; Fujino, D.; Gallegos, R. A.; Gray, N. T.; Hartouni, E. P.; Hogan, G. E.; Holmes, V. H.; Jaramillo, S. A.; Knudsson, J. N.; London, R. K.; Lopez, R. R.; McDonald, T. E.; McClelland, J. B.; Merrill, F. E.; Morley, K. B.; Morris, C. L.; Naivar, F. J.; Parker, E. L.; Park, H. S.; Pazuchanics, P. D.; Pillai, C.; Riedel, C. M.; Sarracino, J. S.; Shelley, F. E., Jr.; Stacy, H. L.; Takala, B. E.; Thompson, Richard; Tucker, H. E.; Yates, G. J.; Ziock, H.-J.; Zumbro, J. D.

    1999-11-01

    The capability has successfully been developed at the Los Alamos Nuclear Science Center (LANSCE) to utilize a spatially and temporally prepared 800 MeV proton beam to produce proton radiographs. A series of proton bursts are transmitted through a dynamic object and transported, via a unique magnetic lens system, to an image plane. The magnetic lens system permits correcting for the effects of multiple coulomb scattering which would otherwise completely blur the spatially transmitted information at the image plane. The proton radiographs are recorded either on a time integrating film plate or with a recently developed multi-frame electronic imaging camera system. The latter technique permits obtaining a time dependent series of proton radiographs with time intervals (modulo 358 ns) up to many microseconds and variable time intervals between images. One electronically shuttered, intensified, CCD camera is required per image. These cameras can detect single protons interacting with a scintillating fiber optic array in the image plane but also have a dynamic range which permits recording radiographs with better than 5% statistics for observation of detailed density variations in the object. A number of tests have been carried out to characterize the quality of the proton radiography system for absolute mass determination, resolution, and dynamic range. Initial dynamic experiments characterized the temporal and spatial behavior of shock propagation in a high explosive sample with up to six images per experiment. Based on experience with the prototype system, a number of upgrades are being implemented including the anticipated capability for enhanced mass discrimination through differential multiple coulomb scattering radiographs and more images with improved imaging techniques.

  6. Proton-induced fragmentation of carbon at energies below 100 MeV

    NASA Technical Reports Server (NTRS)

    Schmitz, M.; Streibel, T.; Roecher, H.; Dreute, J.; Hirzebruch, S. E.; Huentrup, G.; Heinrich, Wolfgang

    1994-01-01

    Radiation effects caused by single cosmic ray particles have been studied for many years in radiobiological experiments for different biological objects and biological end-points. Additionally, single event effects in microelectronic devices have gained large interest. There are two fundamental mechanisms by which a single particle can cause radiation effects. On the one hand, a cosmic ray ion with high linear energy transfer can deposit a high dose along its path. On the other hand, in a nuclear collision, a high dose can be deposited by short range particles emitted from the target nucleus. In low earth orbits a large contribution to target fragmentation events originates from trapped protons which are encountered in the South Atlantic Anomaly. These protons have energies up to a few hundred MeV. We study the fragmentation of C, O and Si nuclei - the target nuclei of biological material and microelectronic devices - in nuclear collisions. Our aim is to measure production cross sections, energy spectra, emission directions and charge correlations of the emitted fragments. The present knowledge concerning these data is rather poor. M. Alurralde et al. have calculated cross sections and average energies of fragments produced from Si using the cascade-evaporation model. D.M. Ngo et al. have used the semiempirical cross section formula of Silberberg and Tsao to calculate fragment yields and the statistical model of Goldhaber to describe the reaction kinematics. Cross sections used in these models have uncertainties within a factor of two. Our data will help to test and improve existing models especially for energies below 300 MeV/nucleon. Charge correlations of fragments emitted in the same interaction are of particular importance, since high doses can be deposited if more than one heavy fragment with a short range is produced.

  7. DETECTORS AND EXPERIMENTAL METHODS: Measurement of the response function and the detection efficiency of an organic liquid scintillator for neutrons between 1 and 30 MeV

    NASA Astrophysics Data System (ADS)

    Huang, Han-Xiong; Ruan, Xi-Chao; Chen, Guo-Chang; Zhou, Zu-Ying; Li, Xia; Bao, Jie; Nie, Yang-Bo; Zhong, Qi-Ping

    2009-08-01

    The light output function of a varphi50.8 mm × 50.8 mm BC501A scintillation detector was measured in the neutron energy region of 1 to 30 MeV by fitting the pulse height (PH) spectra for neutrons with the simulations from the NRESP code at the edge range. Using the new light output function, the neutron detection efficiency was determined with two Monte-Carlo codes, NEFF and SCINFUL. The calculated efficiency was corrected by comparing the simulated PH spectra with the measured ones. The determined efficiency was verified at the near threshold region and normalized with a Proton-Recoil-Telescope (PRT) at the 8-14 MeV energy region.

  8. Study of the (3He,t) Charge Transfer Reaction as a Surrogate for Neutron Energy Between 10 to 20 MeV

    NASA Astrophysics Data System (ADS)

    Basunia, M. S.; Clark, R. M.; Bernstein, L. A.; Lyles, B. F.; Burke, J. T.; Beausang, C. W.; Bleuel, D. L.; Darakchieva, B.; Dietrich, F. S.; Evtimova, M.; Fallon, P.; Gibelin, J.; Lesher, S. R.; McMahan, M. A.; Phair, L.; Rodriguez-Vieitez, E.; Wiedeking, M.

    2008-04-01

    We have indirectly determined the 237Np(n,f) cross section over an equivalent neutron energy range from 10 to 20 MeV using the surrogate reaction 238U(3He,tf). A self-supporting ˜761 μg/cm2 metallic 238U foil was bombarded with a 42 MeV 3He2+ beam from the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory (LBNL). Outgoing charged particles and fission fragments were identified using the Silicon Telescope Array for Reaction Studies (STARS) consisted of two 140 μm and one 1000 μm Micron S2 type silicon detectors. These results were compared with the 237Np(n,f) cross section data from the direct measurements, the Evaluated Nuclear Data File (ENDF/B-VII.0), and the Japanese Evaluated Nuclear Data Library (JENDL 3.3) and found to closely follow those datasets.

  9. Effect of the energy of recoil atoms on conductivity compensation in moderately doped n-Si and n-SiC under irradiation with MeV electrons and protons

    NASA Astrophysics Data System (ADS)

    Kozlovski, V. V.; Lebedev, A. A.; Emtsev, V. V.; Oganesyan, G. A.

    2016-10-01

    Processes of radiation defect formation and conductivity compensation in silicon and silicon carbide irradiated with 0.9 MeV electrons are considered in comparison with the electron irradiation at higher energies. The experimental values of the carrier removal rate at the electron energy of 0.9 MeV are nearly an order of magnitude smaller than the similar values of the parameter for higher energy electrons (6-9 MeV). At the same time, the formation cross-section of primary radiation defects (Frenkel pairs, FPs) is nearly energy-independent in this range. It is assumed that these differences are due to the influence exerted by the energy of primary knocked-on atoms (PKAs). As the PKA energy increases, the average distance between the genetically related FPs grows and, as a consequence, the fraction of FPs unrecombined under irradiation becomes larger. The FP recombination radius is estimated (∼1.1 nm), which makes it possible to ascertain the charge state of the recombining components. Second, the increase in the PKA energy enables formation of new, more complex secondary radiation defects. At electron energies exceeding 15 MeV, the average PKA energies are closer to the values obtained under irradiation with 1 MeV protons, compared with an electron irradiation at the same energy. As for the radiation-induced defect formation, the irradiation of silicon with MeV protons can be, in principle, regarded as a superposition of the irradiation with 1 MeV electrons and that with silicon ions having energy of ∼1 keV, with the "source" of silicon ions generating these ions uniformly across the sample thickness.

  10. Theoretical model analysis of (d ,x n ) reactions on 9Be and 12C at incident energies up to 50 MeV

    NASA Astrophysics Data System (ADS)

    Nakayama, Shinsuke; Kouno, Hiroshi; Watanabe, Yukinobu; Iwamoto, Osamu; Ogata, Kazuyuki

    2016-07-01

    Background: In the design of deuteron accelerator neutron sources, accurate nuclear data of deuteron-induced reactions are indispensable over a wide range of incident energy. Reliable model calculations play an important role in completing the necessary nuclear data since currently available experimental data are insufficient. We have been developing a code system dedicated for the deuteron-induced reactions, called deuteron-induced reaction analysis code system (DEURACS). It was applied successfully to (d ,x p ) reactions at 56 and 100 MeV. Purpose: The purpose of the present work is to investigate the applicability of DEURACS to (d ,x n ) reactions on 9Be and 12C for incident energies below 50 MeV and to clarify neutron production mechanism. Methods: Double-differential thick target neutron yields (TTNYs) from deuteron bombardment on thick Be and C targets are analyzed. The TTNYs are derived using the double differential (d ,x n ) cross sections calculated by DEURACS and the stopping power of deuteron in the target. The calculated TTNYs are decomposed into individual components corresponding to elastic breakup, proton stripping, and statistical decay reactions. Results: The calculated TTNYs reproduced the experimental data quantitatively well in the incident energy range up to 50 MeV. From the analysis, it was found that the proton stripping reaction makes the most dominant contribution to neutron production. Conclusions: DEURACS is applicable to (d ,x n ) reactions on 9Be and 12C for incident energies below 50 MeV. Modeling of the stripping reaction is essential to predict neutron production yields accurately in the design of deuteron accelerator neutron sources.

  11. Telemetry Ranging: Concepts

    NASA Astrophysics Data System (ADS)

    Hamkins, J.; Kinman, P.; Xie, H.; Vilnrotter, V.; Dolinar, S.

    2015-11-01

    Telemetry ranging is a proposed alternative to conventional two-way ranging for determining the two-way time delay between a Deep Space Station (DSS) and a spacecraft. The advantage of telemetry ranging is that the ranging signal on the uplink is not echoed to the downlink, so that telemetry alone modulates the downlink carrier. The timing information needed on the downlink, in order to determine the two-way time delay, is obtained from telemetry frames. This article describes the phase and timing estimates required for telemetry ranging, and how two-way range is calculated from these estimates. It explains why the telemetry ranging architecture does not require the spacecraft transponder to have a high-frequency or high-quality oscillator, and it describes how a telemetry ranging system can be infused in the Deep Space Network.

  12. Complete identification of states in 208Pb below Ex=6.2 MeV

    NASA Astrophysics Data System (ADS)

    Heusler, A.; Jolos, R. V.; Faestermann, T.; Hertenberger, R.; Wirth, H.-F.; von Brentano, P.

    2016-05-01

    The Q3D magnetic spectrograph at the Maier-Leibnitz-Laboratorium of the Ludwig-Maximilians-Universität München and the Technische Universität München (Garching, Germany), was used to study the 208Pb(p ,p' ) , 206,207,208Pb (d,p), and 208Pb(d ,d' ) reactions. One hundred fifty-one states at Ex<6.20 MeV in 208Pb are identified and spin and parity assigned. Four states are newly identified and new spins and/or parities are assigned to 25 states. Tentative spin assignments are done to five states at 5.90 MeV . Nearly 50 levels below Ex=6.20 MeV listed by the Nuclear Data Sheets as of 2007 are recognized to be nonexistent or doubly placed. The schematic shell model describing one-particle-one-hole configurations without residual interaction is extended by including two-particle-two-hole configurations. The number of configurations thus predicted at Ex<6.20 MeV nearly agrees with the number of states identified. Several states with dominant two-particle-two-hole configurations are identified. New isobaric analog resonances in 209Bi with two-particle-one-hole structure are discovered at Eres=17.6 MeV . The excitation energies of 70 states with unnatural parity at Ex<6.20 MeV are found to agree within about 200 keV with one-particle-one-hole configurations predicted by the extended schematic shell model. In contrast, the excitation energies of about 20 natural parity states are more than 0.5 MeV lower than predicted, demonstrating the residual interaction among the configurations to be much larger for natural parity than for unnatural parity.

  13. RADIO RANGING DEVICE

    DOEpatents

    Nieset, R.T.

    1961-05-16

    A radio ranging device is described. It utilizes a super regenerative detector-oscillator in which echoes of transmitted pulses are received in proper phase to reduce noise energy at a selected range and also at multiples of the selected range.

  14. SAR ambiguous range suppression.

    SciTech Connect

    Doerry, Armin Walter

    2006-09-01

    Pulsed Radar systems suffer range ambiguities, that is, echoes from pulses transmitted at different times arrive at the receiver simultaneously. Conventional mitigation techniques are not always adequate. However, pulse modulation schemes exist that allow separation of ambiguous ranges in Doppler space, allowing easy filtering of problematic ambiguous ranges.

  15. Highly Stripped Ion Sources for MeV Ion Implantation

    SciTech Connect

    Hershcovitch, Ady

    2009-06-30

    Original technical objectives of CRADA number PVI C-03-09 between BNL and Poole Ventura, Inc. (PVI) were to develop an intense, high charge state, ion source for MeV ion implanters. Present day high-energy ion implanters utilize low charge state (usually single charge) ion sources in combination with rf accelerators. Usually, a MV LINAC is used for acceleration of a few rnA. It is desirable to have instead an intense, high charge state ion source on a relatively low energy platform (de acceleration) to generate high-energy ion beams for implantation. This de acceleration of ions will be far more efficient (in energy utilization). The resultant implanter will be smaller in size. It will generate higher quality ion beams (with lower emittance) for fabrication of superior semiconductor products. In addition to energy and cost savings, the implanter will operate at a lower level of health risks associated with ion implantation. An additional aim of the project was to producing a product that can lead to long­ term job creation in Russia and/or in the US. R&D was conducted in two Russian Centers (one in Tomsk and Seversk, the other in Moscow) under the guidance ofPVI personnel and the BNL PI. Multiple approaches were pursued, developed, and tested at various locations with the best candidate for commercialization delivered and tested at on an implanter at the PVI client Axcelis. Technical developments were exciting: record output currents of high charge state phosphorus and antimony were achieved; a Calutron-Bemas ion source with a 70% output of boron ion current (compared to 25% in present state-of-the-art). Record steady state output currents of higher charge state phosphorous and antimony and P ions: P{sup 2+} (8.6 pmA), P{sup 3+} (1.9 pmA), and P{sup 4+} (0.12 pmA) and 16.2, 7.6, 3.3, and 2.2 pmA of Sb{sup 3+} Sb {sup 4 +}, Sb{sup 5+}, and Sb{sup 6+} respectively. Ultimate commercialization goals did not succeed (even though a number of the products like high

  16. AGILE as a particle detector: Magnetospheric measurements of 10-100 MeV electrons in L shells less than 1.2

    NASA Astrophysics Data System (ADS)

    Argan, A.; Piano, G.; Tavani, M.; Trois, A.

    2016-04-01

    We study the capability of the AGILE gamma ray space mission in detecting magnetospheric particles (mostly electrons) in the energy range 10-100 MeV. Our measurements focus on the inner magnetic shells with L ≲ 1.2 in the magnetic equator. The instrument characteristics and a quasi-equatorial orbit of ˜500 km altitude make it possible to address several important properties of the particle populations in the inner magnetosphere. We review the on board trigger logic and study the acceptance of the AGILE instrument for particle detection. We find that the AGILE effective geometric factor (acceptance) is R≃50 cm2 sr for particle energies in the range 10-100 MeV. Particle event reconstruction allows to determine the particle pitch angle with the local magnetic field with good accuracy. We obtain the pitch angle distributions for both the AGILE "pointing" phase (July 2007 to October 2009) and the "spinning" phase (November 2009 to present). In spinning mode, the whole range (0-180 degrees) is accessible every 7 min. We find a pitch angle distribution of the "dumbbell" type with a prominent depression near α = 90° which is typical of wave-particle resonant scattering and precipitation in the inner magnetosphere. Most importantly, we show that AGILE is not affected by solar particle precipitation events in the magnetosphere. The satellite trajectory intersects magnetic shells in a quite narrow range (1.0 ≲ L ≲ 1.2); AGILE then has a high exposure to a magnetospheric region potentially rich of interesting phenomena. The large particle acceptance in the 10-100 MeV range, the pitch angle determination capability, the L shell exposure, and the solar-free background make AGILE a unique instrument for measuring steady and transient particle events in the inner magnetosphere.

  17. The temperature dependence of void and bubble formation and growth in aluminium during 600 MeV proton irradiation

    NASA Astrophysics Data System (ADS)

    Victoria, M.; Green, W. V.; Singh, B. N.; Leffers, T.

    1984-05-01

    As a part of a continuing program, we report in the present paper results obtained from irradiating pure aluminium samples in the PIREX facility installed in the 600 MeV proton beam of the accelerator at the Swiss Institute for Nuclear Research (SIN). The aluminium foils have been irradiated at 8 different temperatures in the range from 130°-430°C, to displacement doses of up to 5 dpa and helium contents of over 1000 appm. The TEM examinations have shown that at all irradiation temperatures and displacement doses, helium bubbles are formed uniformly through the whole grain interior. No voids are observed at temperatures above 160° C. At all temperatures, irradiation induced dislocations have been observed, most of them linked to bubbles. At higher temperatures and doses, clear evidence of irradiation induced precipitation has been observed; the precipitates are normally decorated with helium bubbles.

  18. Friction wear and auger analysis of iron implanted with 1.5-MeV nitrogen ions

    NASA Technical Reports Server (NTRS)

    Ferrante, J.; Jones, W. R., Jr.

    1982-01-01

    The effect of implantation of 1.5-MeV nitrogen ions on the friction and wear characteristics of pure iron sliding against steel was studied in a pin-on disk apparatus. An implantation dose of 5 x 10 to the 17th power ions/sq cm was used. Small reductions in initial and steady-state wear rates were observed for nitrogen-implanted iron riders as compared with unimplanted controls. Auger electron spectroscopy revealed a subsurface Gaussian nitrogen distribution with a maximum concentration of 15 at. % at a depth of 8 x 10 to the -7th m. A similar analysis within the wear scar of an implanted rider after 20 microns of wear yielded only background nitrogen concentration, thus giving no evidence for diffusion of nitrogen beyond the implanted range.

  19. Slab optical waveguides in Er3 +-doped tellurite glass by N+ ion implantation at 1.5 MeV

    NASA Astrophysics Data System (ADS)

    Berneschi, Simone; Brenci, Massimo; Nunzi Conti, Gualtiero; Pelli, Stefano; Bettinelli, Marco; Speghini, Adolfo; Bányász, Istvan; Fried, Miklós; Khanh, Nguyen Q.; Lohner, Tivadar; Petrik, Péter; Watterich, Andrea; Zolnai, Zsolt

    2011-07-01

    Slab optical waveguides were fabricated in tung-sten-tellurite glass doped with Er3 + ions by means of nitrogen ion implantation at 1.5 MeV. A wide range of ion doses (from 5.1012 to 8.1016 ions/cm2) was used. Optical characterization, performed by dark-line spectroscopy, revealed that the waveguides were of optical barrier type: the implanted layer exhibited a decrease of the refractive index with respect to the virgin bulk glass, while the region comprised between the sample surface and the end of the ion track acted as an optical guiding structure. It was also demonstrated that a post-implantation annealing process, performed at various temperatures on the samples implanted at higher doses, contributes to the reduction of the barrier region.

  20. Fabrication of copper and gold nanoclusters in MgO (100) by MeV ion implantation

    SciTech Connect

    Zimmerman, R.L.; Ila, D.; Williams, E.K.; Sarkisov, S.S.; Poker, D.B.; Hensley, D.K.

    1997-10-01

    MeV ions of Au and Cu were implanted into single crystals of MgO (100) and the formation of metallic nanoclusters was observed by an indirect method of optical absorption spectrophotometry. Using Mei`s theory the authors related the observed optical absorption band to the formation of nanoclusters and using Doyle`s theory, as well as Rutherford Backscattering Spectrometry (RB S), the authors correlated the fill width half maximum (FWHM) of the absorption bands to the estimated size of the metallic nanoclusters between 1--10 nm. These clusters were formed by implantation above the threshold fluence for cluster formation and by a combination of threshold fluence of the implanted species and thermal annealing. The changes in the estimated size of the nanoclusters, after annealing at temperatures ranging from 5,000 C to 10,000 C, were observed using optical absorption spectrophotometry and calculated using Doyle`s theory.

  1. HRTEM study of track evolution in 120-MeV U irradiated Gd2Ti2O7

    SciTech Connect

    Jozwik Biala, Iwona; Jagielski, Jacek K.; Thome, Lionel; Arey, Bruce W.; Kovarik, Libor; Sattonay, G.; Debelle, A.; Monnet, I.

    2012-09-01

    High resolution Scanning Transmission Electron Microscopy (HRTEM) experiments were performed on Gd2Ti2O7 pyrochlores irradiated with 120-MeV U ions. A judicious choice of irradiation energy, sample preparation (using Focused Ion Beam) and analytical technique (HRTEM) allowed us to visualize the complete evolution of tracks from the surface of samples down to depths exceeding the projected range of irradiating ions. Such features as variation of track diameters, changes in track directions and discontinuous segments of tracks were clearly documented at various depths. By using two different STEM imaging modes: High- and Low-Angle Annular Dark Field imaging (HAADF and LAADF), it was possible to observe the layered structure of tracks composed of an amorphous core surrounded by a strained crystalline envelope.

  2. Transition from participant to spectator fragmentation in Au+Au reactions between 60A and 150A MeV

    SciTech Connect

    Zbiri, K.; Aichelin, J.; Le Fevre, A.; Lukasik, J.; Reisdorf, W.; Lynen, U.; Mueller, W. F. J.; Orth, H.; Schwarz, C.; Sfienti, C.; Trautmann, W.; Turzo, K.; Gulminelli, F.; Lopez, O.; Vient, E.; Zwieglinski, B.; Chbihi, A.; Frankland, J. D.; Wieleczko, J. P.; Charvet, J. L.

    2007-03-15

    Using the quantum molecular dynamics approach, we analyzed the results of the recent INDRA Collaboration Au+Au experiments at GSI in the energy range between 60A and 150A MeV. It turns out that in this energy region, the transition toward a participant-spectator scenario takes place. The large Au+Au system displays, in the simulations as in the experiment, simultaneously dynamical and statistical behavior, which we analyze in detail. The composition of fragments close to midrapidity follows statistical laws, and the system shows bimodality, i.e., a sudden transition between different fragmentation patterns, as a function of centrality, as expected for a phase transition. The fragment spectra at small and large rapidities, on the other hand, are determined by dynamics, and the system as a whole does not come to equilibrium--an observation that is confirmed by FOPI Collaboration experiments for the same system.

  3. Production cross-sections of radionuclides from α-induced reactions on natural copper up to 50MeV.

    PubMed

    Usman, Ahmed Rufai; Khandaker, Mayeen Uddin; Haba, Hiromitsu; Otuka, Naohiko; Murakami, Masashi; Komori, Yukiko

    2016-08-01

    The excitation functions were measured for the (nat)Cu(α,x)(66,67)Ga,(65)Zn,(57,58,60)Co reactions in the energy range of 16.5 -50MeV. A conventional stacked-foil activation technique combined with HPGe γ-ray spectrometry was employed to determine cross-sections. The measured cross-sections were critically compared with relevant previous experimental data and also with the evaluated data in the TENDL-2014 library. Present results confirmed some of the previous experimental data, whereas only a partial agreement was found with the evaluated data. The measured data are useful for reducing the existing discrepancies in the literature, to improve the nuclear reaction model codes, and to enrich the experimental database towards various applications.

  4. HRTEM study of track evolution in 120-MeV U irradiated Gd2Ti2O7

    NASA Astrophysics Data System (ADS)

    Jozwik-Biala, I.; Jagielski, J.; Thomé, L.; Arey, B.; Kovarik, L.; Sattonnay, G.; Debelle, A.; Monnet, I.

    2012-09-01

    High Resolution Scanning Transmission Electron Microscopy (HRTEM) experiments were performed on Gd2Ti2O7 pyrochlore irradiated with 120-MeV U ions. A judicious choice of irradiation energy, sample preparation (using Focused Ion Beam) and analytical technique (HRTEM) allowed us to visualize the complete evolution of tracks from the surface of samples down to depths exceeding the projected range of irradiating ions. Such features as variation of track diameters, changes in track directions and discontinuous segments of tracks were clearly documented at various depths. By using two different Scanning Transmission Electron Microscopy (STEM) imaging modes: High- and Low-Angle Annular Dark Field imaging (HAADF and LAADF), it was possible to observe the radial substructure of tracks composed of an amorphous core surrounded by a damaged and strained crystalline envelope.

  5. Neutron-Helium-3 Analyzing Powers between 1.60 and 5.54 MeV

    NASA Astrophysics Data System (ADS)

    Esterline, J. H.; Crowell, A. S.; Fallin, B. A.; Howell, C. R.; Hutcheson, A.; Kidd, M. F.; Kiser, M. R.; Macri, R. A.; Tajima, S.; Tornow, W.; Crowe, B. J.; Pedroni, R. S.; Weisel, G. J.

    2007-10-01

    As part of a broader investigation of the four-nucleon system, the analyzing power for neutron-helium-3 scattering was measured at Triangle Universities Nuclear Laboratory (TUNL) at five neutron energies between 1.60 and 5.54 MeV. Measurements were made at around thirty angles for each energy using neutron beams, produced by the T(p,n)^3He and D(d,n)^3He source reactions, with polarizations ranging from 0.3 to 0.5. The data, recently corrected for finite geometry and multiple scattering effects, are compared to earlier experimental results as well as new ab initio calculations, as from [1]. [1] A. Deltuva and A.C. Fonseca, Phys. Rev. C 75, 014005 (2007).

  6. Production cross-sections of radionuclides from α-induced reactions on natural copper up to 50MeV.

    PubMed

    Usman, Ahmed Rufai; Khandaker, Mayeen Uddin; Haba, Hiromitsu; Otuka, Naohiko; Murakami, Masashi; Komori, Yukiko

    2016-08-01

    The excitation functions were measured for the (nat)Cu(α,x)(66,67)Ga,(65)Zn,(57,58,60)Co reactions in the energy range of 16.5 -50MeV. A conventional stacked-foil activation technique combined with HPGe γ-ray spectrometry was employed to determine cross-sections. The measured cross-sections were critically compared with relevant previous experimental data and also with the evaluated data in the TENDL-2014 library. Present results confirmed some of the previous experimental data, whereas only a partial agreement was found with the evaluated data. The measured data are useful for reducing the existing discrepancies in the literature, to improve the nuclear reaction model codes, and to enrich the experimental database towards various applications. PMID:27227905

  7. Temperature dependent surface modification of T91 steel under 3.25 MeV Fe-ion implantation

    NASA Astrophysics Data System (ADS)

    Zhu, Huiping; Wang, Zhiguang; Cui, Minghuan; Li, Bingsheng; Gao, Xing; Sun, Jianrong; Yao, Cunfeng; Wei, Kongfang; Shen, Tielong; Pang, Lilong; Zhu, Yabin; Li, Yuanfei; Wang, Ji; Xie, Erqing

    2015-01-01

    Ion implantation is an established technique for modifying the surface properties of a wide range of materials. In this research, temperature dependent surface modification induced by Fe-ion implantation in T91 steel was investigated. The T91 samples were implanted with 3.25 MeV Fe-ions to fluence of 1.7 × 1016 ions/cm2 at room temperature, 300 and 450 °C, respectively. After implantation, the T91 samples were characterized by means of positron annihilation Doppler broadening spectroscopy (PADBS) and nano-indention technology (NIT). It was found that the concentration of open-volume defects in T91 samples decreased with increasing implantation temperature. From NIT analysis, it was found that all the samples were hardened after implantation and the hardness of the implanted T91 samples increased with increasing implantation temperature.

  8. Neutron field produced by 25 MeV deuteron on thick beryllium for radiobiological study; energy spectrum.

    PubMed

    Takada, Masashi; Mihara, Erika; Sasaki, Michiya; Nakamura, Takashi; Honma, Toshihiko; Kono, Koji; Fujitaka, Kazunobu

    2004-01-01

    Biological data is necessary for estimation of protection from neutrons, but there is a lack of data on biological effects of neutrons for radiation protection. Radiological study on fast neutrons has been done at the National Institute of Radiological Sciences. An intense neutron source has been produced by 25 MeV deuterons on a thick beryllium target. The neutron energy spectrum, which is essential for neutron energy deposition calculation, was measured from thermal to maximum energy range by using an organic liquid scintillator and multi-sphere moderated 3He proportional counters. The spectrum of the gamma rays accompanying the neutron beam was measured simultaneously with the neutron spectrum using the organic liquid scintillator. The transmission by the shield of the spurious neutrons originating from the target was measured to be less than 1% by using the organic liquid scintillator placed behind the collimator. The measured neutron energy spectrum is useful in dose calculations for radiobiology studies.

  9. High-temperature scintillation of alumina under 32 MeV 63Cu5+ heavy-ion irradiation

    NASA Astrophysics Data System (ADS)

    Lederer, S.; Akhmadaliev, S.; von Borany, J.; Gütlich, E.; Lieberwirth, A.; Zimmermann, J.; Ensinger, W.

    2015-09-01

    Polycrystalline alumina samples (α-Al2O3, purity: 99.8%) were irradiated with 63Cu5+ ions of 32 MeV kinetic energy (≈0.5 MeV/u) up to fluences of 1014 ions/cm2 at various temperatures ranging from 295 to 973 K. Ion beam induced luminescence and emission spectra were monitored at wavelengths from 320 to 800 nm. Optical absorption measurements were performed to deduce color center formation. Results were evaluated by the Birks model to determine the material's radiation hardness. The applicability of alumina as scintillation screens for ion beam diagnostics could be extended by enhanced temperature operation. Analysis of the emission spectra shows a complex color center formation behavior as a function of fluence and temperature.

  10. (65)Cu isomeric cross sections for (n,α) reaction using approximately 14MeV neutrons.

    PubMed

    Durusoy, Ayşe; Reyhancan, Iskender Atilla; Akçalı, Özgür

    2015-05-01

    In this paper, activation cross-section measurements for the (65)Cu(n,α)(62m)Co (T1/2=13.86min.) reaction at six different neutron energies ranging from 13.6 and 14.9MeV are presented. The fast neutrons were produced via (3)H(d, n)(4)He reactions from an SAMES T-400 neutron generator. An activation technique was used to measure induced gamma activities. A high-resolution gamma-ray spectrometer with a high-purity germanium (HpGe) detector was used to acquire the data. The measured cross section data were corrected for gamma-ray attenuations, pulse pile-up effects, dead time, variations in neutron flux, and contributions from scattered low-energy neutrons. The measured cross sections were compared with statistical model calculations (TALYS 1.6 code), the experimental data available in the literature and the data obtained from TENDL.

  11. Measurement of the {pi}{sup +}{ital p{searrow}} analyzing power at 68.3 MeV

    SciTech Connect

    Wieser, R.; Denig, A.; von Hagel, U.; Joram, C.; Kluge, W.; Andermann, R.; Bilger, R.; Clement, H.; Foehl, K.; Heitlinger, K.; Wagner, G.J.; van den Brandt, B.; Foroughi, F.; Hautle, P.; Konter, A.; Mango, S.; Kovalev, A. |||

    1996-10-01

    The analyzing power {ital A}{sub {ital y}} for {pi}{sup +}{ital p{searrow}} scattering at 68.3 MeV has been measured at the Paul Scherrer Institut with the magnetic spectrometer LEPS. The measurements cover the angular range 40{degree}{le}{theta}{sub lab}{le}70{degree}. The protons have been polarized in a butanol target, operated in frozen spin mode. The {ital S}31 phase shift comes out by about 1{degree} smaller than the Koch-Pietarinen [Nucl. Phys. A {bold 336}, 331 (1980)] phase shift analysis, supporting the necessity of an alternative dispersion analysis of {pi}{ital N} scattering to determine the {sigma} term and the {pi}{ital N} coupling constant. {copyright} {ital 1996 The American Physical Society.}

  12. Beam-dump/diagnostics box for a 10-kA 50-MeV, 50-ns electron beam

    SciTech Connect

    White, J.M.; Fessenden, T.J.; Fontaine, R.A.; Harvey, A.R.; Paul, A.C.

    1983-03-09

    We have developed a dump for the ATA beam that consists of a series of carbon plates whose collective thickness totals approximately 1.5 ranges at 50 MeV. The energy dissipated in the plates is radiated to a water-cooled wall. The dump is designed to dissipate up to 175 kW of average power. A small hole along the axis of the plates forms a beamlet that passes through an energy analyzer. The analyzer consists of a 60/sup 0/ bending magnet and two high-sensitivity beam-current/position monitors. The ratio of the beamlet current to full current is used to estimate the beam emittance.

  13. Telemetry Ranging: Signal Processing

    NASA Astrophysics Data System (ADS)

    Hamkins, J.; Kinman, P.; Xie, H.; Vilnrotter, V.; Dolinar, S.

    2016-02-01

    This article describes the details of the signal processing used in a telemetry ranging system in which timing information is extracted from the downlink telemetry signal in order to compute spacecraft range. A previous article describes telemetry ranging concepts and architecture, which are a slight variation of a scheme published earlier. As in that earlier work, the telemetry ranging concept eliminates the need for a dedicated downlink ranging signal to communicate the necessary timing information. The present article describes the operation and performance of the major receiver functions on the spacecraft and the ground --- many of which are standard tracking loops already in use in JPL's flight and ground radios --- and how they can be used to provide the relevant information for making a range measurement. It also describes the implementation of these functions in software, and performance of an end-to-end software simulation of the telemetry ranging system.

  14. Cross sections for proton induced high energy γ -ray emission (PIGE) in reaction 19 F(p, αγ)16 O at incident proton energies between 1.5 and 4 MeV

    NASA Astrophysics Data System (ADS)

    Cabanelas, P.; Cruz, J.; Fonseca, M.; Henriques, A.; Lourenço, F.; Luís, H.; Machado, J.; Pires Ribeiro, J.; Sánchez-Benítez, A. M.; Teubig, P.; Velho, P.; Zarza-Moreno, M.; Galaviz, D.; Jesus, A. P.

    2016-08-01

    We have studied the high energy gamma-rays produced in the reaction 19 F(p, αγ)16 O for incident proton energies from 1.5 to 4.0 MeV over NaF/Ag and CaF2/Ag thin targets in two different sets of data. Gamma-rays were detected with a High Purity Ge detector with an angle of 130° with respect to the beam axis. The cross-sections for the high energy gamma-rays of 6.129, 6.915 and 7.115 MeV have been measured for the whole group between 5 and 7.2 MeV with accuracy better than 10%. A new energy range was covered and more points are included in the cross-sections data base expanding the existing set of data. Results are in agreement with previous measurements in similar conditions.

  15. Energy-range relations for hadrons in nuclear matter

    NASA Technical Reports Server (NTRS)

    Strugalski, Z.

    1985-01-01

    Range-energy relations for hadrons in nuclear matter exist similarly to the range-energy relations for charged particles in materials. When hadrons of GeV kinetic energies collide with atomic nuclei massive enough, events occur in which incident hadron is stopped completely inside the target nucleus without causing particle production - without pion production in particular. The stoppings are always accompanied by intensive emission of nucleons with kinetic energy from about 20 up to about 400 MeV. It was shown experimentally that the mean number of the emitted nucleons is a measure of the mean path in nuclear matter in nucleons on which the incident hadrons are stopped.

  16. Telemetry-Based Ranging

    NASA Technical Reports Server (NTRS)

    Hamkins, Jon; Vilnrotter, Victor A.; Andrews, Kenneth S.; Shambayati, Shervin

    2011-01-01

    A telemetry-based ranging scheme was developed in which the downlink ranging signal is eliminated, and the range is computed directly from the downlink telemetry signal. This is the first Deep Space Network (DSN) ranging technology that does not require the spacecraft to transmit a separate ranging signal. By contrast, the evolutionary ranging techniques used over the years by NASA missions, including sequential ranging (transmission of a sequence of sinusoids) and PN-ranging (transmission of a pseudo-noise sequence) whether regenerative (spacecraft acquires, then regenerates and retransmits a noise-free ranging signal) or transparent (spacecraft feeds the noisy demodulated uplink ranging signal into the downlink phase modulator) relied on spacecraft power and bandwidth to transmit an explicit ranging signal. The state of the art in ranging is described in an emerging CCSDS (Consultative Committee for Space Data Systems) standard, in which a pseudo-noise (PN) sequence is transmitted from the ground to the spacecraft, acquired onboard, and the PN sequence is coherently retransmitted back to the ground, where a delay measurement is made between the uplink and downlink signals. In this work, the telemetry signal is aligned with the uplink PN code epoch. The ground station computes the delay between the uplink signal transmission and the received downlink telemetry. Such a computation is feasible because symbol synchronizability is already an integral part of the telemetry design. Under existing technology, the telemetry signal cannot be used for ranging because its arrival-time information is not coherent with any Earth reference signal. By introducing this coherence, and performing joint telemetry detection and arrival-time estimation on the ground, a high-rate telemetry signal can provide all the precision necessary for spacecraft ranging.

  17. Analysis of a measured neutron background below 6 MeV for fast-neutron imaging systems

    NASA Astrophysics Data System (ADS)

    Ide, K.; Becchetti, M. F.; Flaska, M.; Poitrasson-Riviere, A.; Hamel, M. C.; Polack, J. K.; Lawrence, C. C.; Clarke, S. D.; Pozzi, S. A.

    2012-12-01

    Detailed and accurate information on the neutron background is relevant for many applications that involve radiation detection, both for non-coincidence and coincidence countings. In particular, for the purpose of developing advanced neutron-detection techniques for nuclear non-proliferation and nuclear safeguards, the energy-dependent, ground-level, neutron-background information is needed. There are only a few previous studies available about the neutron background below 10 MeV, which is a typical neutron energy range of interest for nuclear non-proliferation and nuclear-safeguards applications. Thus, there is a potential for further investigation in this energy range. In this paper, neutron-background measurement results using organic-liquid scintillation detectors are described and discussed, with a direct application in optimization simulations of a fast-neutron imager based on liquid scintillators. The measurement was performed in summer 2011 in Ann Arbor, Michigan, USA, and the measurement setup consisted of several EJ-309 liquid scintillators and a fast waveform digitizer. The average neutron flux below 6 MeV was measured to be approximately 4e-4 counts/cm2/s. In addition, the relationship between the neutron-background count rate and various environmental quantities, such as humidity, at Earth's ground level was investigated and the results did not reveal any straightforward dependences. The measured pulse height distribution (PHD) was unfolded to determine the energy spectrum of the background neutrons. The unfolded neutron-background spectrum was implemented to a previously-created MCNPX-PoliMi model of the neutron-scatter camera and simple-backprojection images of the background neutrons were acquired. Furthermore, a simulated PHD was obtained with the MCNPX-PoliMi code using the "Cosmic-Ray Shower Library" (CRY) source sub-routine which returns various types of radiation, including neutrons and photons at a surface, and accounts for solar cycle

  18. The Evolution of Swift/BAT blazars and the origin of the MeV background

    SciTech Connect

    Ajello, M.; Costamante, L.; Sambruna, R.M.; Gehrels, N.; Chiang, J.; Rau, A.; Escala, A.; Greiner, J.; Tueller, J.; Wall, J.V.; Mushotzky, R.F.; /NASA, Goddard

    2009-10-17

    We use 3 years of data from the Swift/BAT survey to select a complete sample of X-ray blazars above 15 keV. This sample comprises 26 Flat-Spectrum Radio Quasars (FSRQs) and 12 BL Lac objects detected over a redshift range of 0.03 < z < 4.0. We use this sample to determine, for the first time in the 15-55 keV band, the evolution of blazars. We find that, contrary to the Seyfert-like AGNs detected by BAT, the population of blazars shows strong positive evolution. This evolution is comparable to the evolution of luminous optical QSOs and luminous X-ray selected AGNs. We also find evidence for an epoch-dependence of the evolution as determined previously for radio-quiet AGNs. We interpret both these findings as a strong link between accretion and jet activity. In our sample, the FSRQs evolve strongly, while our best-fit shows that BL Lacs might not evolve at all. The blazar population accounts for 10-20% (depending on the evolution of the BL Lacs) of the Cosmic X-ray background (CXB) in the 15-55 keV band. We find that FSRQs can explain the entire CXB emission for energies above 500 keV solving the mystery of the generation of the MeV background. The evolution of luminous FSRQs shows a peak in redshift (z{sub c} = 4.3 {+-} 0.5) which is larger than the one observed in QSOs and X-ray selected AGNs. We argue that FSRQs can be used as tracers of massive elliptical galaxies in the early Universe.

  19. Low dose irradiation creep of pure nickel. [17 or 15 MeV deuterons

    SciTech Connect

    Henager, C.H. Jr.

    1984-10-01

    A detailed climb-controlled glide model of low dose irradiation creep has been developed to rationalize irradiation creep data of pure nickel irradiated in a light ion irradiation creep apparatus. Experimental irradiation creep data were obtained to study the effects of initial microstructure and stress on low dose irradiation creep in pure nickel. Pure nickel specimens (99.992% Ni), with three different microstructures, were irradiated with 17 or 15 MeV deuterons at 473 K and stresses ranging from 0.35 to 0.9 of the unirradiated yield stress. Transmission electron microscopy revealed that the microstructure following irradiation to 0.05 dpa consisted of a high density of small dislocation loops, some small voids and network dislocations. The creep model predicted creep rates proportional to the mobile dislocation density and a comparison of experimental irradiation creep rates as a function of homologous stress revealed a dependence on initial microstructure of the magnitude predicted by the measured dislocation densities. The three microstructures that were irradiated consisted of 85% and 25% cold-worked Ni specimens and well-annealed Ni specimens. A weak stress dependence of irradiation creep was observed in 85% cold-worked Ni in agreement with experimental determinations of the stress dependence of irradiation creep by others. The weak stress dependence was shown to be a consequence of the stress independence of the dislocation climb velocity and the weak stress dependence of the barrier removal process. The irradiation creep rate was observed to be proportional to the applied stress. This linear stress dependence was suggested to be due to the stress dependence of the mobile dislocation density. 101 references, 27 figures, 11 tables.

  20. Ambiguities in the elastic scattering of 8 MeV neutrons from adjacent nuclei

    SciTech Connect

    Smith, A.B.; Lawson, R.D.; Guenther, P.T.

    1989-10-01

    Ratios of the cross sections for elastic scattering of 8 MeV neutrons from adjacent nuclei are measured over the angular range {approx}20{degree} {minus} 160{degree} for the target pairs {sup 51}V/Cr, {sup 59}Co/{sup 58}Ni, Cu/Zn, {sup 89}Y/{sup 93}Nb, {sup 89}Y/Zr, {sup 93}Nb/Zr, In/Cd and {sup 209}Bi/Pb. The observed ratios vary from unity by as much as a factor of {approx}2 at some angles for the lighter target pairs. Approximately half the measured ratios are reasonably explained by a simple spherical optical model, including size and isospin contributions. In all cases, the geometry of the real optical--model potential is essentially the same for neighboring nuclei, and the real--potential strengths are consistent with the Lane model. In contrast, it is found that the imaginary potential may be quite different for adjacent nuclei, and the nature of this difference is examined. It is shown that the spin--spin interaction has a negligible effect on the calculation of the elastic--scattering ratios, but that channel coupling, leading to a large reorientation of the target ground state, can be a consideration, particularly in the {sup 59}Co/{sup 58}Ni case. In the A {approx} 50--60 region the calculated ratios are sensitive to spin--orbit effects, but the exact nature of this interaction must await more definitive polarization measurements. The measured and calculated results suggest that the concept of a conventional global'' or even regional'' optical potential provides no more than a qualitative representation of the physical reality for a number of cases. 48 refs., 14 figs., 3 tabs.

  1. COMPTEL Studies of Gamma-Ray Bursts at MeV Energies

    NASA Technical Reports Server (NTRS)

    McConnell, Mark L.

    1999-01-01

    The purpose of this program was to analyse and interpret gamma-ray burst (GRB) data using both telescope mode data and single detector burst mode data from COMPTEL. Collectively, these data span the energy range from 300 keV up to 30 MeV. The initial goal of our proposal was to perform a standard analysis for each significant GRB event seen by COMPTEL. This includes GRBs that are registered by the telescope mode data as well as GRBs that are registered only in the burst mode data. (The latter category includes both GRBs that he outside of the FoV as well as GRBs within the FoV that are too weak to be seen in the telescope mode.) A second goal of our proposal was to define a set of data products (including deconvolved photon spectra) that, for each detected GRB event, would be made available via the COMPTEL GRB Web Page. The third goal of our program was to perform more detailed studies of selected GRB events. This represented a continuation of past GRB studies by the COMPTEL team. In general, we have met with only limited success in achieving these goals, in part due to the limited resources provided and our philosophy of utilizing local high school students to participate in this effort. Using local high school student support, however, we expect that considerable progress will be made in our efforts to catalog the COMPTEL gamma-ray burst data between now and the end of the current academic year. In addition, observations with COMPTEL contributed to an analysis of GRB 990123, the first gamma-ray burst with simultaneous optical observations.

  2. Irradiation damage induced on polyethylene terephtalate by 1.6 MeV deuteron ions

    NASA Astrophysics Data System (ADS)

    Abdesselam, M.; Djebara, M.; Chami, A. C.; Siad, M.

    2008-09-01

    The irradiation damage caused on polyethylene terephtalate (Mylar, PET) samples by 1.6 MeV deuteron ions has been measured using simultaneously the nuclear reaction analysis (NRA) and the transmission energy loss (TEL) techniques. The irradiation was carried out at normal incidence relative to the target surface with the irradiation beam being used as the analysis beam. The evolution of the overall damage during irradiation was evaluated by measuring the variation of the energy loss of the deuteron beam passing through the target. For this purpose, a solid state Si detector placed at a forward angle of 30° relative to the incident beam direction was used. The NRA spectra recorded by a second Si detector located backward at 150° allowed the evaluation of the carbon and the oxygen depletion. The beam spot size was circular in shape and 1 mm in diameter and the beam current was set at 5 nA. The ion fluence was increased up to the value of 2.5 × 1016 deuterons/cm2. It was observed that the target energy loss decreased steadily as the fluence increased and levelled off at high fluence. The 16O(d,p0)17O, 16O(d,p1)17O∗ and 12C(d,p0)13C reactions were used for monitoring the evolution of the oxygen and carbon content as a function of the deuteron fluence. A monotonic decrease of the oxygen content with the increase of ion fluence was observed. At the highest fluence the oxygen depletion reached a value of about 75%. For carbon, a weak depletion was observed at fluence ranging from 2.5 × 1015 d/cm2 to 1.0 × 1016 d/cm2 followed by a levelling-off with a total loss around 20%.

  3. The study of optical property of sapphire irradiated with 73 MeV Ca ions

    NASA Astrophysics Data System (ADS)

    Yang, Yitao; Zhang, Chonghong; Song, Yin; Gou, Jie; Liu, Juan; Xian, Yongqiang

    2015-12-01

    Single crystals of sapphire were irradiated with 73 MeV Ca ions at room temperature to the fluences of 0.1, 0.5 and 1.0 × 1014 ions/cm2. Optical properties of these samples were characterized by ultraviolet-visible spectrometry (UV-VIS) and fluorescence spectrometer (PL). In UV-VIS spectra, it is observed the absorbance bands from oxygen single vacancy (F and F+ color centers) and vacancy pair (F2+ and F22+ color centers). The oxygen single vacancy initially increases rapidly and then does not increase in the fluence range from 0.1 to 0.5 × 1014 ions/cm2. When the fluence is higher than 0.5 × 1014 ions/cm2, oxygen single vacancy starts to increase again. Oxygen vacancy pair increases monotonically with fluence for all irradiated samples. The variation of oxygen single vacancy with fluence is probably associated with the recombination of oxygen vacancies with Al interstitials and complex defect formation (such as vacancy clusters). From PL spectra, two emission bands around 3.1 and 2.34 eV are observed. The PL intensity of the emission band around 3.1 eV decreases for all the irradiated samples. For the emission band around 2.34 eV, the PL intensity initially decreases, and then increases with fluence. Meanwhile, the peak position of the emission band around 2.34 eV gradually shifts to high energy direction with increase of fluence. The decrease of the intensity of the emission bands around 3.1 and 2.34 eV could be induced by stress from the damage layer in the irradiated samples. The shift of peak position for the emission band around 2.34 eV is induced by the appearance of emission band from Al interstitials.

  4. Observations of 1-30 MeV gamma rays from the galactic center

    NASA Technical Reports Server (NTRS)

    Zanrosso, E.; Long, J. L.; Zych, A. D.; White, R. S.

    1981-01-01

    Preliminary results are reported for gamma ray observations of the galactic center region made during a 15-hour balloon flight from Alice Springs, Australia on April 18, 1979. The observations were carried out with the UGR double-scatter gamma-ray telescope at energies of 1 to 30 MeV. The observations are compatible with a galactic source of approximately equal brightness along the region of system II galactic longitudes between 300 and 60 deg. The energy distribution joins smoothly to previous spark chamber results at energies above 30 MeV and to scintillator results below 1 MeV. It appears to be a combination of nuclear gamma ray lines superimposed on a power-law bremsstrahlung spectrum. The metastable C-12 line at 4.4 MeV appears to be present with a significance of about 16 standard deviations. The flux in the line is 0.0006 + or - 0.0003 photons/sq cm per sec per rad. The oxygen line at 6.1 MeV does not seem to appear significantly above background.

  5. Gamma ray lines from solar flares. [with 2.2 MeV line being strongest

    NASA Technical Reports Server (NTRS)

    Ramaty, R.; Lingenfelter, R. E.

    1974-01-01

    The strongest line, both predicted theoretically and detected observationally at 2.2 MeV, is due to neutron capture by protons in the photosphere. The neutrons are produced in nuclear reactions of flare accelerated particles which also positrons and prompt nuclear gamma rays. From the comparison of the observed and calculated intensities of the lines at 4.4 or 6.1 MeV to that of the 2.2 MeV line, it is possible to deduce the spectrum of accelerated nuclei in the flare region; and from the absolute intensities of these lines, it is possible to obtain the total number of accelerated nuclei at the sun. The study of the 2.2 MeV line also gives information on the amount of He-3 in the photosphere. The study of the line at 0.51 MeV resulting from positron annihilation complements the data obtained from the other lines; in addition it gives information on the temperature and density in the annihilation region.

  6. Modification of semiconductor or metal nanoparticle lattices in amorphous alumina by MeV heavy ions

    NASA Astrophysics Data System (ADS)

    Bogdanović Radović, I.; Buljan, M.; Karlušić, M.; Jerčinović, M.; Dražič, G.; Bernstorff, S.; Boettger, R.

    2016-09-01

    In the present work we investigate effects of MeV heavy ions (from 0.4 MeV Xe to 15 MeV Si) on regularly ordered nanoparticle (NP) lattices embedded in amorphous alumina matrix. These nanostructures were produced by self-assembling growth using magnetron-sputtering deposition. From grazing incidence small-angle x-ray scattering measurements we have found that the used MeV heavy ions do not change the NP sizes, shapes or distances among them. However, ions cause a tilt of the entire NP lattice in the direction parallel to the surface. The tilt angle depends on the incident ion energy, type and the applied fluence and a nearly linear increase of the tilt angle with the ion fluence and irradiation angle was found. This way, MeV heavy ion irradiation can be used to design custom-made NP lattices. In addition, grazing incidence small-angle x-ray scattering can be effectively used as a method for the determination of material redistribution/shift caused by the ion hammering effect. For the first time, the deformation yield in amorphous alumina was determined for irradiation performed at the room temperature.

  7. Independent isotopic yields in 25 MeV and 50 MeV proton-induced fission of natU

    NASA Astrophysics Data System (ADS)

    Penttilä, H.; Gorelov, D.; Elomaa, V.-V.; Eronen, T.; Hager, U.; Hakala, J.; Jokinen, A.; Kankainen, A.; Karvonen, P.; Moore, I. D.; Parkkonen, J.; Peräjärvi, K.; Pohjalainen, I.; Rahaman, S.; Rinta-Antila, S.; Rissanen, J.; Rubchenya, V. A.; Saastamoinen, A.; Simutkin, V.; Sonoda, T.; Weber, C.; Voss, A.; Äystö, J.

    2016-04-01

    Independent isotopic yields for elements from Zn to La in the 25 MeV proton-induced fission of {}^{nat}U were determined with the JYFLTRAP facility. In addition, isotopic yields for Zn, Ga, Rb, Sr, Zr, Pd and Xe in the 50 MeV proton-induced fission of {}^{nat}U were measured. The deduced isotopic yield distributions are compared with a Rubchenya model, the GEF model with universal parameters and the semi-empirical Wahl model. Of these, the Rubchenya model gives the best overall agreement with the obtained data. Combining the isotopic yield data with mass yield data to obtain the absolute independent yields was attempted. The result depends on the mass yield distribution.

  8. Micron Accurate Absolute Ranging System: Range Extension

    NASA Technical Reports Server (NTRS)

    Smalley, Larry L.; Smith, Kely L.

    1999-01-01

    The purpose of this research is to investigate Fresnel diffraction as a means of obtaining absolute distance measurements with micron or greater accuracy. It is believed that such a system would prove useful to the Next Generation Space Telescope (NGST) as a non-intrusive, non-contact measuring system for use with secondary concentrator station-keeping systems. The present research attempts to validate past experiments and develop ways to apply the phenomena of Fresnel diffraction to micron accurate measurement. This report discusses past research on the phenomena, and the basis of the use Fresnel diffraction distance metrology. The apparatus used in the recent investigations, experimental procedures used, preliminary results are discussed in detail. Continued research and equipment requirements on the extension of the effective range of the Fresnel diffraction systems is also described.

  9. Limits on the antiproton/proton ratio in the cosmic radiation from 100 MeV to 1580 MeV

    NASA Technical Reports Server (NTRS)

    Salamon, M. H.; Mckee, S.; Musser, J. A.; Tarle, G.; Tomasch, A.

    1990-01-01

    A search for antiprotons (p-bars) in the cosmic radiation with energies below 1580 MeV at the top of the atmosphere was performed using the PBAR balloon-borne magnetic spectrometer. No antiprotons were observed in 124,000 proton events. For the energy interval 100-640 MeV, an upper limit is reported to the p-bar/p ratio of 2.8 x 10 to the -5th at the top of the atmosphere, after correcting for instrumental efficiencies and contributions from secondary particles. No antiproton was observed in the energy interval 640-1580 MeV, which yields an upper limit to the p-bar/p ratio of 6.1 x 10. By combining both data sets, the limits on the p-bar/p ratio can be improved to 2.0 x 10 to the -5th. The detector performance and instrumental efficiencies of the individual detector components are discussed. A detail Monte Carlo calculation was used to evaluate the instrumental efficiency for both antiprotons and protons as a function of momentum.

  10. Tests of a Compton imaging prototype in a monoenergetic 4.44 MeV photon field—a benchmark setup for prompt gamma-ray imaging devices

    NASA Astrophysics Data System (ADS)

    Golnik, C.; Bemmerer, D.; Enghardt, W.; Fiedler, F.; Hueso-González, F.; Pausch, G.; Römer, K.; Rohling, H.; Schöne, S.; Wagner, L.; Kormoll, T.

    2016-06-01

    The finite range of a proton beam in tissue opens new vistas for the delivery of a highly conformal dose distribution in radiotherapy. However, the actual particle range, and therefore the accurate dose deposition, is sensitive to the tissue composition in the proton path. Range uncertainties, resulting from limited knowledge of this tissue composition or positioning errors, are accounted for in the form of safety margins. Thus, the unverified particle range constrains the principle benefit of proton therapy. Detecting prompt γ-rays, a side product of proton-tissue interaction, aims at an on-line and non-invasive monitoring of the particle range, and therefore towards exploiting the potential of proton therapy. Compton imaging of the spatial prompt γ-ray emission is a promising measurement approach. Prompt γ-rays exhibit emission energies of several MeV. Hence, common radioactive sources cannot provide the energy range a prompt γ-ray imaging device must be designed for. In this work a benchmark measurement-setup for the production of a localized, monoenergetic 4.44 MeV γ-ray source is introduced. At the Tandetron accelerator at the HZDR, the proton-capture resonance reaction 15N(p,α γ4.439)12C is utilized. This reaction provides the same nuclear de-excitation (and γ-ray emission) occurrent as an intense prompt γ-ray line in proton therapy. The emission yield is quantitatively described. A two-stage Compton imaging device, dedicated for prompt γ-ray imaging, is tested at the setup exemplarily. Besides successful imaging tests, the detection efficiency of the prototype at 4.44 MeV is derived from the measured data. Combining this efficiency with the emission yield for prompt γ-rays, the number of valid Compton events, induced by γ-rays in the energy region around 4.44 MeV, is estimated for the prototype being implemented in a therapeutic treatment scenario. As a consequence, the detection efficiency turns out to be a key parameter for prompt

  11. A high resolution liquid xenon imaging telescope for 0.3-10 MeV gamma-ray astrophysics: Construction and initial balloon flights

    NASA Technical Reports Server (NTRS)

    Aprile, Elena

    1994-01-01

    An instrument is described which will provide a direct image of gamma-ray line or continuum sources in the energy range 300 keV to 10 MeV. The use of this instrument to study the celestial distribution of the (exp 26)Al isotope by observing the 1.809 MeV deexcitation gamma-ray line is illustrated. The source location accuracy is 2' or better. The imaging telescope is a liquid xenon time projection chamber coupled with a coded aperture mask (LXe-CAT). This instrument will confirm and extend the COMPTEL observations from the Compton Gamma-Ray Observatory (CGRO) with an improved capability for identifying the actual Galactic source or sources of (exp 26)Al, which are currently not known with certainty. sources currently under consideration include red giants on the asymptotic giant branch (AGB), novae, Type 1b or Type 2 supernovae, Wolf-Rayet stars and cosmic-rays interacting in molecular clouds. The instrument could also identify a local source of the celestial 1.809 MeV gamma-ray line, such as a recent nearby supernova.

  12. Neutron spectra produced by 30, 35 and 40 MeV proton beams at KIRAMS MC-50 cyclotron with a thick beryllium target

    NASA Astrophysics Data System (ADS)

    Shin, Jae Won; Bak, Sang-In; Ham, Cheolmin; In, Eun Jin; Kim, Do Yoon; Min, Kyung Joo; Zhou, Yujie; Park, Tae-Sun; Hong, Seung-Woo; Bhoraskar, V. N.

    2015-10-01

    Neutrons over a wide range of energies are produced by bombarding a 1.05 cm thick beryllium target with protons of different energies delivered by the MC-50 Cyclotron of the Korea Institute of Radiological Medical Sciences (KIRAMS). The neutron flux Φ(En) versus neutron energy En, produced by protons of 30, 35, and 40 MeV energies, was obtained by using the GEANT4 code with a data-based hadronic model. For the experimental validation of the simulated neutron spectra, a number of pure aluminum and iron oxide samples were irradiated with the neutrons produced by 30, 35, and 40 MeV protons at 20 μA beam current. The gamma-ray activities of 24Na and 56Mn produced, respectively, through 27Al(n,α)24Na and 56Fe(n,p)56Mn reactions were measured by a HPGe detector. The neutron flux Φ(En) at each neutron energy from the simulation was multiplied with the evaluated cross-sections σ(En) of the respective nuclear reaction, and the summation ∑ Φ(En) σ(En) was calculated over the neutron spectrum for each proton energy of 30, 35, and 40 MeV. The measured gamma-ray activities of 24Na and 56Mn were found in good agreement with the activities estimated by using the summed values of ∑ Φ(En) σ(En) along with other parameters in a neutron activation method.

  13. A comparison of 4 MeV Proton and Co-60 gamma irradiation induced degradation in the electrical characteristics of N-channel MOSFETs

    NASA Astrophysics Data System (ADS)

    Anjum, Arshiya; Vinayakprasanna, N. H.; Pradeep, T. M.; Pushpa, N.; Krishna, J. B. M.; Gnana Prakash, A. P.

    2016-07-01

    N-channel depletion MOSFETs were irradiated with 4 MeV Proton and Co-60 gamma radiation in the dose range of 100 krad(Si) to 100 Mrad(Si). The electrical characteristics of MOSFET such as threshold voltage (Vth), density of interface trapped charges (ΔNit), density of oxide trapped charges (ΔNot), transconductance (gm), mobility (μ), leakage current (IL) and drain saturation current (ID Sat) were studied as a function of dose. A considerable increase in ΔNit and ΔNot and decrease in Vth,gm, μ, and ID Sat was observed after irradiation. The results of 4 MeV Proton irradiation were compared with that of Co-60 gamma radiation and it is found that the degradation is more for the devices irradiated with 4 MeV Protons when compared with the Co-60 gamma radiation. This indicates that Protons induce more trapped charges in the field oxide region when compared to the gamma radiation.

  14. Gamma-radiation with E gamma 5 MeV detected from Seyfert galaxy 3C120 and region with 1" = 190 deg and b" = 20 deg

    NASA Technical Reports Server (NTRS)

    Damle, S. V.; Fradkin, M. I.; Iyudin, A. F.; Kirillov-Ugryumov, V. G.; Kotov, Y. D.; Kurnosova, L. V.; Smirnov, Y. V.; Yurov, V. N.

    1985-01-01

    The observation of the Galaxy anticenter region in gamma-rays with E gamma = 5 / 100 MeV was made by gamma-telescope Natalya-1 in a balloon flight. The flight was performed at the ceiling 5.1 + or - 0.1 g/sq cm, magnetic cutoff being 17 GV. The description of the instrument and the analysis of the experiment conditions are given. The tracks of electron-positron pairs generated by gamma-quanta in the convertors were detected by wire spark chambers. The recorded events were classified manually by an operator using a graphic display into three classes: pairs, single and bad events. The arrival angle of gamma-quanta and their energy for selected gamma-ray events (pairs and singles) were determined through multiple scattering of pair components in the convertors. On the basis of the data obtained the celestial maps were made in gamma-rays for E sub gamma 5 MeV and E gamma 20 MeV energy ranges.

  15. Statistical analysis of energetic electrons (3. 4-16 MeV) at geosynchronous altitude and their relationship to interplanetary parameters. Master's thesis

    SciTech Connect

    Smith, W.L.

    1983-12-01

    This analysis attempted to examine the relationship between energetic electrons in the magnetosphere between the energy levels of 3.4-16 MeV, solar wind speed, and the Bz component of the Interplanetary Magnetic Field (IMF). The statistical analysis was accomplished using the SPSS computerized package and data from DOD spacecraft 1979-053 at geosynchronous altitude. The electron flux data from this satellite was compared statistically with IMF and solar sind plasma data measured by other spacecraft located in the solar wind stream. Analytic techniques used included graphical plotting, descriptive statistics, scatter plots, correlation analysis, and analysis of variance (ANOVA) tests. This statistical analysis of energetic electrons at geosynchronous altitude and their relationship to solar wind speed and the IMF Bz component resulted in different findings for electron flux above and below approximately 6.6 MeV energy level. There was a weak, positive correlation between electron flux in the energy ranges 3.4 - 4.9 and 4.9 - 6.6 MeV and values of solar wind speed, after two days passage.

  16. Response of the Li-7-enriched Cs2LiYCl6:Ce (CLYC-7) scintillator to 6-60 MeV neutrons

    NASA Astrophysics Data System (ADS)

    Woolf, Richard S.; Hutcheson, Anthony L.; Phlips, Bernard F.; Wulf, Eric A.

    2015-12-01

    We discuss a test campaign designed to irradiate the 7Li-enriched Cs2LiYCl6:Ce3+ (CLYC-7) scintillator with 6-60 MeV neutrons using the cyclotron located at the Crocker Nuclear Laboratory in Davis, CA. CLYC-7 is a newly developed scintillator that exhibits the ability to make good γ-ray measurements and has the ability to detect and discriminate fast neutrons via pulse shape discrimination (PSD) while functioning as a spectrometer. This allows a single detector to make good measurement of both stimuli simultaneously. The response of this scintillation detector has been investigated below 20 MeV [1] but has yet to be explored for energies greater than 20 MeV. Understanding the spectral and pulse shape response across a broad energy range is important for any radiation detection instrumentation capable of detecting multiple species. At the highest energies sampled, the CLYC-7 PSD demonstrated not only the standard electron/proton separation expected in a mixed γ/n field but the ability to discriminate locally produced deuterons, tritons and α particles. We show the results from the four different neutron beam energies sampled during the experiment. Lastly, we present the results obtained for relating the light output equivalence between electrons and protons/deuterons.

  17. Fluence-to-dose conversion coefficients from monoenergetic neutrons below 20 MeV based on the VIP-Man anatomical model

    NASA Astrophysics Data System (ADS)

    Bozkurt, A.; Chao, T. C.; Xu, X. G.; Bozkurt, A.; Chao, T. C.

    2000-10-01

    A new set of fluence-to-absorbed dose and fluence-to-effective dose conversion coefficients have been calculated for neutrons below 20 MeV using a whole-body anatomical model, VIP-Man, developed from the high-resolution transverse colour photographic images of the National Library of Medicine's Visible Human Project®. Organ dose calculations were performed using the Monte Carlo code MCNP for 20 monoenergetic neutron beams between 1×10-9 MeV and 20 MeV under six different irradiation geometries: anterior-posterior, posterior-anterior, right lateral, left lateral, rotational and isotropic. The absorbed dose for 24 major organs and effective dose results based on the realistic VIP-Man are presented and compared with those based on the simplified MIRD-based phantoms reported in the literature. Effective doses from VIP-Man are not significantly different from earlier results for neutrons in the energy range studied. There are, however, remarkable deviations in organ doses due to the anatomical differences between the image-based and the earlier mathematical models.

  18. Automatic range selector

    DOEpatents

    McNeilly, Clyde E.

    1977-01-04

    A device is provided for automatically selecting from a plurality of ranges of a scale of values to which a meter may be made responsive, that range which encompasses the value of an unknown parameter. A meter relay indicates whether the unknown is of greater or lesser value than the range to which the meter is then responsive. The rotatable part of a stepping relay is rotated in one direction or the other in response to the indication from the meter relay. Various positions of the rotatable part are associated with particular scales. Switching means are sensitive to the position of the rotatable part to couple the associated range to the meter.

  19. Resonance frequency control for the KOMAC 100-MeV drift tube linac

    NASA Astrophysics Data System (ADS)

    Kwon, Hyeok-Jung

    2015-02-01

    A 100-MeV proton accelerator has been developed, and the operation and beam service started at the Korea Multi-purpose Accelerator Complex (KOMAC) in July 2013. The accelerator consists of a 50-keV proton injector, a 3-MeV radio-frequency quadrupole (RFQ) and a 100-MeV drift tube linac (DTL). The resonance frequencies of the DTL tanks are controlled by using the resonance frequency control cooling system (RCCS), installed at every DTL tank. Until now, the RCCS has been operating in the constant temperature mode. If the system is to be stabilized better, the RCCS must be operated in the frequency control mode. For this purpose, studies, including the relation between the resonance frequency and RCCS operation temperature, were done under various conditions. In this paper, the preparations for the frequency control loop of the RCCS are described.

  20. Evidence for a 3.8 MeV state in 9Be

    NASA Astrophysics Data System (ADS)

    Smith, R.; Wheldon, C.; Freer, M.; Curtis, N.; Kokalova, Tz.; Almaraz-Calderon, S.; Aprahamian, A.; Ashwood, N. I.; Barr, M.; Bucher, B.; Copp, P.; Couder, M.; Fang, X.; Goldring, G.; Jung, F.; Lesher, S. R.; Lu, W.; Malcolm, J. D.; Roberts, A.; Tan, W. P.; Ziman, V. A.

    2016-07-01

    The breakup reaction 9Be(4He,3 α )n was measured using an array of four double-sided silicon strip detectors at beam energies of 22 and 26 MeV. Excited states in 9Be up to 8 MeV were populated and reconstructed through measurements of the charged reaction products. Evidence is given for a state in 9Be at 3 .82-0.09+0.08 MeV with Γ =1240-90+270 keV. This is consistent with two recent measurements of a state with similar properties in the mirror nucleus 9B. An analysis of the reduced widths (g.s.8Be channel) of this state along with the proposed mirror state has led to a firm limit of J ≤7 /2 and a tentative assignment of Jπ=1 /2- or 3 /2- .

  1. A proposed diagnostic for time-resolved 14 MeV neutron measurements on TFTR

    SciTech Connect

    Ku, L.P.; Nazikian, R.; Prorvitch, V.

    1990-06-01

    A novel method for time resolved measurements of the 14 MeV neutron flux in an intense 2.5 MeV neutron and {gamma}-ray background has been developed. Discrimination against the background 2.5 MeV neutron and {gamma}-ray flux is achieved by the use of polyethylene and lead shielding. A high detection efficiency of DT neutrons is obtained by the use of large volume plastic scintillators and photomultiplier tube designed for operating in high magnetic field environments. Design computations for a such a detector system on TFTR show that an absolute detection efficiency of {approximately}10{sup {minus}8} counts per DT neutron may be obtained. A source strength of 10{sup 13} DT n/s may readily be detected by this method using both count mode and current mode operation with a resolution of {approximately}10 ms within a statistical accuracy of {approximately}5%. 12 refs., 8 figs., 2 tabs.

  2. Commissioning and first operational experience of the 400 MeV Linac at Fermilab

    SciTech Connect

    Junck, K.; Allen, L.; Kroc, T.; MacLachlan, J.; McCrory, E.; Moretti, A.; Noble, R.; Popovic, M.; Schmidt, C.

    1994-07-01

    Commissioning of the Fermilab High Energy Linac during September and October of 1993 has increased the energy of the H- linac from 200 to 400 MeV. The Linac Upgrade is one portion of the Fermilab Upgrad and is intended to reduce the incoherent space-charge tuneshift at injection into the 8 GeV Booster. To accomplish this increase in energy within the existing enclosure, four 201.25 MHz drift-tube linac tankshave been replaced by seven 805 MHz side-coupled cavity modules to accelerate the beam from 116 MeV to 400 MeV. Each module is driven with a klystron amplifier delivering 10 MW of peak power for 60 {mu}sec with a maximum pulse repetition rate of 15 Hz. Nominal beam current is 35 mA with a pulselength of 40 {mu}sec. Results from commissioning and operational experience during Fermilab Collider Run 1B are presented.

  3. Neutron-induced 2.2 MeV background in gamma ray telescopes

    NASA Technical Reports Server (NTRS)

    Zanrosso, E. M.; Long, J. L.; Zych, A. D.; White, R. S.

    1985-01-01

    Neutron-induced gamma ray production is an important source of background in Compton scatter gamma ray telescopes where organic scintillator material is used. Most important is deuteron formation when atmospheric albedo and locally produced neutrons are thermalized and subsequently absorbed in the hydrogenous material. The resulting 2.2 MeV gamma ray line radiation essentially represents a continuous isotropic source within the scintillator itself. Interestingly, using a scintillator material with a high hydrogen-to-carbon ratio to minimize the scintillator material with a high hydrogen-to-carbon ratio to minimize the neutron-induced 4.4 MeV carbon line favors the np reaction. The full problem of neutron-induced background in Compton scatter telescopes has been previously discussed. Results are presented of observations with the University of California balloon-borne Compton scatter telescope where the 2.2 MeV induced line emission is prominently seen.

  4. RF phase stability in the 100-MeV proton linac operation

    NASA Astrophysics Data System (ADS)

    Seol, Kyung-Tae

    2015-02-01

    The 100-MeV proton linac of the Korea multi-purpose accelerator complex (KOMAC) has been operated to provide a proton beam to users. The 100-MeV linac consists of a 3-MeV radio-frequency quadrupole accelerator (RFQ), four 20-MeV drift-tube linac (DTL) tanks, two medium-energy beam-transmitter (MEBT) tanks, and seven 100-MeV DTL tanks. The requirements of the field stability are within ±1% in RF amplitude and ±1 degree in RF phase. The RF phase stability is influenced by a RF reference line, RF transmission lines, and a RF control system. The RF reference signal is chosen to be a 300-MHz local oscillator (LO) signal, and a rigid copper coaxial line with temperature control was installed for an RF reference distribution. A phase stability of ±0.1 degrees was measured under a temperature change of ±0.1 °C. A digital feedback control system with a field-programmable gate-array (FPGA) module was adopted for a high RF stability. The RF phase was maintained within ±0.1 degrees with a dummy cavity and was within ±0.3 degrees at RFQ operation. In the case of the 20-MeV DTL tanks, one klystron drives 4 tanks, and the input phases of 4 tanks were designed to be in phase. The input phases of 4 tanks were fixed within ±1 degree by adjusting a phase shifter in each waveguide.

  5. Neutron induced fission of U isotopes up to 100 MeV

    SciTech Connect

    Lestone, J.P.; Gavron, A.

    1993-10-01

    We have developed a statistical model description of the neutron induced fission of U isotopes using densities of intrinsic states and spin cut off parameters obtained directly from appropriate Nilsson model single particle levels. The first chance fission cross sections are well reproduced when the rotational contributions to the nuclear level densities are taken into account. In order to fit the U(n,f) cross sections above the threshold of second chance fission, we need to: (1) assume that the triaxial level density enhancement is washed out at an excitation energy of {approximately}7 MeV above the triaxial barriers with a width of {approximately}1 MeV, implying a {gamma} deformation for the first barriers of 10{degree} < {gamma} < 20{degree}; and (2) include pre-equilibrium particle emission in the calculations. Above an incoming neutron kinetic energy of {approximately}17 MeV our statistical model U(n,f) cross sections increasingly overestimate the experimental data when so called ``good`` optical model potentials are used to calculate the compound nucleus formation cross sections. This is not surprising since at these high energies little data exists on the scattering of neutrons to help guide the choice of optical model parameters. A satisfactory reproduction of all the available U(n,f) cross sections above 17 MeV is obtained by a simple scaling of our calculated compound nucleus formation cross sections. This scaling factor falls from 1.0 at 17 MeV to 0.82 at 100 MeV.

  6. Exploratory study of fission product yields of neutron-induced fission of 235U , 238U , and 239Pu at 8.9 MeV

    NASA Astrophysics Data System (ADS)

    Bhatia, C.; Fallin, B. F.; Gooden, M. E.; Howell, C. R.; Kelley, J. H.; Tornow, W.; Arnold, C. W.; Bond, E.; Bredeweg, T. A.; Fowler, M. M.; Moody, W.; Rundberg, R. S.; Rusev, G. Y.; Vieira, D. J.; Wilhelmy, J. B.; Becker, J. A.; Macri, R.; Ryan, C.; Sheets, S. A.; Stoyer, M. A.; Tonchev, A. P.

    2015-06-01

    Using dual-fission chambers each loaded with a thick (200 -400 -mg /c m2) actinide target of 235 ,238U or 239Pu and two thin (˜10 -100 -μ g /c m2) reference foils of the same actinide, the cumulative yields of fission products ranging from 92Sr to 147Nd have been measured at En= 8.9 MeV . The 2H(d ,n ) 3He reaction provided the quasimonoenergetic neutron beam. The experimental setup and methods used to determine the fission product yield (FPY) are described, and results for typically eight high-yield fission products are presented. Our FPYs for 235U(n ,f ) , 238U(n ,f ) , and 239Pu(n ,f ) at 8.9 MeV are compared with the existing data below 8 MeV from Glendenin et al. [Phys. Rev. C 24, 2600 (1981), 10.1103/PhysRevC.24.2600], Nagy et al. [Phys. Rev. C 17, 163 (1978), 10.1103/PhysRevC.17.163], Gindler et al. [Phys. Rev. C 27, 2058 (1983), 10.1103/PhysRevC.27.2058], and those of Mac Innes et al. [Nucl. Data Sheets 112, 3135 (2011), 10.1016/j.nds.2011.11.009] and Laurec et al. [Nucl. Data Sheets 111, 2965 (2010), 10.1016/j.nds.2010.11.004] at 14.5 and 14.7 MeV, respectively. This comparison indicates a negative slope for the energy dependence of most fission product yields obtained from 235U and 239Pu , whereas for 238U the slope issue remains unsettled.

  7. Characterization of PARIS LaBr3(Ce)-NaI(Tl) phoswich detectors up to Eγ ~ 22 MeV

    NASA Astrophysics Data System (ADS)

    Ghosh, C.; Nanal, V.; Pillay, R. G.; Anoop, K. V.; Dokania, N.; Pal, Sanjoy; Pose, M. S.; Mishra, G.; Rout, P. C.; Kumar, Suresh; Pandit, Deepak; Mondal, Debasish; Pal, Surajit; Banerjee, S. R.; Napiorkowski, P. J.; Dorvaux, O.; Kihel, S.; Mathieu, C.; Maj, A.

    2016-05-01

    In order to understand the performance of the PARIS (Photon Array for the studies with Radioactive Ion and Stable beams) detector, detailed characterization of two individual phoswich (LaBr3(Ce)-NaI(Tl)) elements has been carried out. The detector response is investigated over a wide range of Eγ = 0.6 to 22.6 MeV using radioactive sources and employing 11B(p,γ) reaction at Ep = 163 keV and Ep = 7.2 MeV . The linearity of energy response of the LaBr3(Ce) detector is tested upto 22.6 MeV using three different voltage dividers. The data acquisition system using CAEN digitizers is set up and optimized to get the best energy and time resolution. The energy resolution of ~ 2.1% at Eγ = 22.6 MeV is measured for the configuration giving best linearity up to high energy. Time resolution of the phoswich detector is measured with a 60Co source after implementing CFD algorithm for the digitized pulses and is found to be excellent (FWHM ~ 315 ps). In order to study the effect of count rate on detectors, the centroid position and width of the Eγ = 835 keV peak were measured upto 220 kHz count rate. The measured efficiency data with radioactive sources are in good agreement with GEANT4 based simulations. The total energy spectrum after the add-back of energy signals in phoswich components is also presented.

  8. RBE and genetic susceptibility of mouse and rat spermatogonial stem cells to protons, heavy charged particles and 1.5 MeV neutrons

    NASA Astrophysics Data System (ADS)

    Vaglenov, A.; Fedorenko, B.; Kaltenboeck, B.

    The main purpose of the present study is to provide data on RBE and genetic susceptibility in the mouse and the rat when exposed to protons, HZE particles and neutrons. Genetic damage from exposure to 50 MeV and 9 GeV protons, 4 GeV/nucleon helium ions, 4 GeV/nucleon carbon ions and 1.5 MeV neutrons was studied in adult (CBA × C57Bl/6J) F1 mice. Damage from 9 GeV protons and 4 GeV helium ions was studied in adult Wistar rats. The incidence of reciprocal translocations (RT) induced in the spermatogonial stem cells of each species was recorded. RBE values were derived by comparing linear regression coefficients from dose-responses within the same dose-range for each of the radiation types tested and 60Co γ-rays or by means of a direct nonparametric method. RT yields measured after mouse and rat spermatogonial irradiation with protons, heavy charged particles and neutrons fit the linear model of the dose-response relationship. Relative to 60Co γ-rays, RBE values are as follows for mouse spermatogonia: 0.9 for 50 MeV protons; 1.3 for 9 GeV protons; 0.7 for 4 GeV helium ions; and 1.3 for 4 GeV carbon ions. For rat spermatogonia, values were: 1.7 for 9 GeV protons and 1.3 for helium ions. Compared to mice irradiated using the same experimental design, rats were more susceptible to high-LET radiations, with susceptibility assessed by genetic damage to their spermatogonial stem cells. The RBE of 1.5 MeV neutron is about 6.6.

  9. Attenuation of 10 MeV electron beam energy to achieve low doses does not affect Salmonella spp. inactivation kinetics

    NASA Astrophysics Data System (ADS)

    Hieke, Anne-Sophie Charlotte; Pillai, Suresh D.

    2015-05-01

    The effect of attenuating the energy of a 10 MeV electron beam on Salmonella inactivation kinetics was investigated. No statistically significant differences were observed between the D10 values of either Salmonella 4,[5],12:i:- or a Salmonella cocktail (S. 4,[5],12:i:-, Salmonella Heidelberg, Salmonella Newport, Salmonella Typhimurium, Salmonella) when irradiated with either a non-attenuated 10 MeV eBeam or an attenuated 10 MeV eBeam (~2.9±0.22 MeV). The results show that attenuating the energy of a 10 MeV eBeam to achieve low doses does not affect the inactivation kinetics of Salmonella spp. when compared to direct 10 MeV eBeam irradiation.

  10. Range Scheduling Aid (RSA)

    NASA Technical Reports Server (NTRS)

    Logan, J. R.; Pulvermacher, M. K.

    1991-01-01

    Range Scheduling Aid (RSA) is presented in the form of the viewgraphs. The following subject areas are covered: satellite control network; current and new approaches to range scheduling; MITRE tasking; RSA features; RSA display; constraint based analytic capability; RSA architecture; and RSA benefits.

  11. Loss of alpha-like MeV fusion products from TFTR

    SciTech Connect

    Zweben, S.J.; Boivin, R.L.; Diesso, M.; Hayes, S.E.; Hendel, H.W.; Park, H.; Strachan, J.D.

    1990-03-01

    A detailed comparison between the observed and expected loss of alpha-like MeV fusion products in TFTR is presented. The D-D fusion products (mainly the 1 MeV triton) were measured with an 2-D imaging scintillation detector. The expected first-orbit loss was calculated with a simple Lorentz orbit code. In almost all cases the measured loss was consistent with the expected first-orbit loss model. Exceptions are noted for small major radius plasmas and during strong MHD activity. 37 refs., 28 figs.

  12. Protactinium neutron-induced fission up to 200 MeV

    NASA Astrophysics Data System (ADS)

    Maslov, V.

    2010-03-01

    The theoretical evaluation of 230-233Pa(n,F) cross sections is based on direct data, 230-234Pa fission probabilities and ratios of fission probabilities in first-chance and emissive fission domains, surrogate for neutroninduced fission. First chance fission cross sections trends of Pa are based on consistent description of 232Th(n,F), 232Th(n,2n) and 238U(n,F), 238U(n,xn) data, supported by the ratio surrogate data by Burke et al., 2006, for the 237U(n,F) reaction. Ratio surrogate data on fission probabilities of 232Th(6 Li,4 He)234Pa and 232 Th(6 Li,d)236U by Nayak et al., 2008, support the predicted 233Pa(n, F) cross section at En=11.5-16.5 MeV. The predicted trends of 230-232Pa(n, F) cross section up to En=20 MeV, are consistent with fissilities of Pa nuclides, extracted by 232Th(p,F) (Isaev et al., 2008) and 232Th(p,3n) (Morgenstern et al., 2008) data analysis. The excitation energy and nucleon composition dependence of the transition from asymmetric to symmetric scission for fission observables of Pa nuclei is defined by analysis of p-induced fission of 232Th at Ep=1-200 MeV. Predominantly symmetric fission in 232Th(p,F) at En( p)=200 MeV as revealed by experimental branching ratios (Dujvestijn et al., 1999) is reproduced. Steep transition from asymmetric to symmetric fission with increase of nucleon incident energy is due to fission of neutron-deficient Pa (A≤229) nuclei. A structure of the potential energy surface (a drop of f f symmetric and asymmetric fission barriers difierence (EfSYM - EfASYM) from ~3.5 MeV to ~1 MeV) of N-deficient Pa nuclides (A≤226) and available phase space at outer fission saddles, are shown to be responsible for the sharp increase with En( p) of the symmetric fission component contribution for 232Th(p,F) and 230-233 Pa(n, F) reactions. That is a strong evidence of emissive fission nature of moderately excited Pa nuclides, reliably quantified only up to En( p)~20(30) MeV. Predicted fission cross section of 232Pa(n,F) coincides

  13. Inelastic scattering of 61 MeV protons by pb-207

    NASA Technical Reports Server (NTRS)

    Owais, M.

    1976-01-01

    Differential cross sections for the excitation of the first four neutron-hole states and the doublet at 2.61 MeV by 61.2 MeV protons were measured. The data are analyzed in terms of both a purely collective model description and a microscopic model supplemented by macroscopic core polarization. A realistic two-body interaction is used and knock-on amplitudes are included. Core polarization is found to be important but represents a relatively smaller contribution than in most nuclei previously studied. A parallel analysis of similar data at lower proton bombarding energies reveals a surprisingly strong energy dependence of the reaction mechanisms.

  14. Interaction of MeV ions and VUV photons with polymers and high molecular hydrocarbons

    NASA Astrophysics Data System (ADS)

    Mahfouz, R. M.; Sauer, M.; Atwa, S. T.; Kaiser, R. I.; Roessler, K.

    1992-03-01

    Organic solids such as polymethylene, polyethylene, polyoxymethylene, aliphatic and cyclic paraffins, naphthalene, anthracene and kerogen were irradiated at 77 K with 10-20 MeV cyclotron ions (p, 3He) and up to 10 eV photons. The products were analysed by quadrupole mass spectrometry (QMS). Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and gas chromatography (GC). Besides radiolytic fragmentation, also synthesis of new and complex compounds was observed as a consequence of hot carbon chemistry. Vacuum ultraviolet (VUV) irradiation proved to be less effective in the buildup of new structures than MeV ions, due to its lower linear energy transfer.

  15. Clarification of the three-body decay of 12C (12.71 MeV).

    PubMed

    Fynbo, H O U; Prezado, Y; Bergmann, U C; Borge, M J G; Dendooven, P; Huang, W X; Huikari, J; Jeppesen, H; Jones, P; Jonson, B; Meister, M; Nyman, G; Riisager, K; Tengblad, O; Vogelius, I S; Wang, Y; Weissman, L; Wilhelmsen Rolander, K; Aystö, J

    2003-08-22

    Using beta decays of a clean source of 12N produced at the IGISOL facility, we have measured the breakup of the 12C (12.71 MeV) state into three alpha particles with a segmented particle detector setup. The high quality of the data permits solving the question of the breakup mechanism of the 12.71 MeV state, a longstanding problem in few-body nuclear physics. Among existing models, a modified sequential model fits the data best, but systematic deviations indicate that a three-body description is needed.

  16. Production of Highly Polarized Positrons Using Polarized Electrons at MeV Energies

    NASA Astrophysics Data System (ADS)

    Abbott, D.; Adderley, P.; Adeyemi, A.; Aguilera, P.; Ali, M.; Areti, H.; Baylac, M.; Benesch, J.; Bosson, G.; Cade, B.; Camsonne, A.; Cardman, L. S.; Clark, J.; Cole, P.; Covert, S.; Cuevas, C.; Dadoun, O.; Dale, D.; Dong, H.; Dumas, J.; Fanchini, E.; Forest, T.; Forman, E.; Freyberger, A.; Froidefond, E.; Golge, S.; Grames, J.; Guèye, P.; Hansknecht, J.; Harrell, P.; Hoskins, J.; Hyde, C.; Josey, B.; Kazimi, R.; Kim, Y.; Machie, D.; Mahoney, K.; Mammei, R.; Marton, M.; McCarter, J.; McCaughan, M.; McHugh, M.; McNulty, D.; Mesick, K. E.; Michaelides, T.; Michaels, R.; Moffit, B.; Moser, D.; Muñoz Camacho, C.; Muraz, J.-F.; Opper, A.; Poelker, M.; Réal, J.-S.; Richardson, L.; Setiniyaz, S.; Stutzman, M.; Suleiman, R.; Tennant, C.; Tsai, C.; Turner, D.; Ungaro, M.; Variola, A.; Voutier, E.; Wang, Y.; Zhang, Y.; PEPPo Collaboration

    2016-05-01

    The Polarized Electrons for Polarized Positrons experiment at the injector of the Continuous Electron Beam Accelerator Facility has demonstrated for the first time the efficient transfer of polarization from electrons to positrons produced by the polarized bremsstrahlung radiation induced by a polarized electron beam in a high-Z target. Positron polarization up to 82% have been measured for an initial electron beam momentum of 8.19 MeV /c , limited only by the electron beam polarization. This technique extends polarized positron capabilities from GeV to MeV electron beams, and opens access to polarized positron beam physics to a wide community.

  17. Design of a compact spectrometer for high-flux MeV gamma-ray beams

    SciTech Connect

    Corvan, D. J. Sarri, G.; Zepf, M.

    2014-06-15

    A novel design for a compact gamma-ray spectrometer is presented. The proposed system allows for spectroscopy of high-flux multi-MeV gamma-ray beams with MeV energy resolution in a compact design. In its basic configuration, the spectrometer exploits conversion of gamma-rays into electrons via Compton scattering in a low-Z material. The scattered electron population is then spectrally resolved using a magnetic spectrometer. The detector is shown to be effective for gamma-ray energies between 3 and 20 MeV. The main properties of the spectrometer are confirmed by Monte Carlo simulations.

  18. Experimental evidence of the superfocusing effect for axially channeled MeV protons

    NASA Astrophysics Data System (ADS)

    Motapothula, M.; Petrović, S.; Nešković, N.; Breese, M. B. H.

    2016-08-01

    Sub-Ångström focusing of megaelectronvolt (MeV) ions within axial channels was predicted over 10 years ago, but evidence proved elusive. We present experimental angular distributions of axially channeled MeV protons in a 55-nm-thick (001) silicon membrane through which multiple scattering is negligible. Fine angular structure is in excellent agreement with Monte Carlo simulations based on three interaction potentials, providing indirect evidence of the existence of the superfocusing effect with flux enhancement of around 800 within a focused beam width of ˜20 pm .

  19. Design of a compact spectrometer for high-flux MeV gamma-ray beams.

    PubMed

    Corvan, D J; Sarri, G; Zepf, M

    2014-06-01

    A novel design for a compact gamma-ray spectrometer is presented. The proposed system allows for spectroscopy of high-flux multi-MeV gamma-ray beams with MeV energy resolution in a compact design. In its basic configuration, the spectrometer exploits conversion of gamma-rays into electrons via Compton scattering in a low-Z material. The scattered electron population is then spectrally resolved using a magnetic spectrometer. The detector is shown to be effective for gamma-ray energies between 3 and 20 MeV. The main properties of the spectrometer are confirmed by Monte Carlo simulations.

  20. Thin Object Radiography with a 2.2 MeV Pulsed Power Machine

    NASA Astrophysics Data System (ADS)

    Haines, Todd; Danielson, Jeremy; Wood, W. Monty

    2015-06-01

    An experimental series was performed at a pulsed-power 2.2 MeV flash radiography machine to determine the lower limits of its mass sensitivity. This machine uses a rod-pinch diode with accelerating potential of 2.2 MeV and 50 ns pulse duration. Tungsten, aluminum, and titanium rod anodes were used to tune the emitted bremsstrahlung spectrum; as well as aluminum and beryllium filter materials. Analysis of thin tantalum foils shows a mass sensitivity as low as 300 μg/cm2. This is a factor of 5 better than previous measurements.

  1. Neutron-induced charged-particle emission studies below 100 MeV at WNR

    SciTech Connect

    Haight, R.C.; Lee, T.M.; Sterbenz, S.M.

    1994-07-01

    Charged-particles produced by neutron bombardment of selected targets with Z=5 through 53 have been studied for neutron energies from 1 MeV to about 100 MeV using the spallation neutron source at WNR/LAMPF. Particle detection with energy measurement and particle identification is accomplished by two-element {Delta}E-E counters, three-element {Delta}E{sub l}-{Delta}E{sub 2}-E counters or with pulse-shape discrimination using scintillators directly in the neutron beam. The experimental techniques for these measurements are described and comparisons made among the different approaches. This presentation introduces five papers contributed to this conference.

  2. Effect of 100MeV oxygen ion irradiation on silicon NPN power transistor

    NASA Astrophysics Data System (ADS)

    Kumar, M. Vinay; Krishnakumar, K. S.; Dinesh, C. M.; Krishnaveni, S.; Ramani

    2012-06-01

    The radiation response of npn Bipolar junction transistor (BJT) has been examined for 100 MeV O7+ ion. Key electrical properties like Gummel characteristics, dc current gain and capacitance-voltage of 100MeV O7+ ion irradiated transistor were studied before and after irradiation. The device was decapped and the electrical characterizations were performed at room temperature. Base current is observed to be more sensitive than collector current and gain appears to be degraded with ion fluence, also considerable degradation in C-V characteristics is observed and doping concentration is found to be increased along with the increase in ion fluence.

  3. MeV negative ion generation from ultra-intense laser interaction with a water spray

    SciTech Connect

    Ter-Avetisyan, S.; Ramakrishna, B.; Borghesi, M.; Doria, D.; Zepf, M.; Sarri, G.; Ehrentraut, L.; Steinke, S.; Sandner, W.; Schnuerer, M.; Andreev, A.; Nickles, P. V.; Tikhonchuk, V.

    2011-08-01

    MeV negative oxygen ions are obtained from a water spray target irradiated by high intensity (5 x 10{sup 19} W/cm{sup 2}) and ultrashort (50 fs) laser pulses. Generation of negative ions is ascribed to electron-capture processes that the laser-accelerated high-energy positive ion experiences when it interacts with atoms in the spray. This mechanism implies the existence of a large number of MeV neutral oxygen atoms, which is consistent with indirect experimental evidence.

  4. Home range and travels

    USGS Publications Warehouse

    Stickel, L.F.; King, John A.

    1968-01-01

    The concept of home range was expressed by Seton (1909) in the term 'home region,' which Burr (1940, 1943) clarified with a definition of home range and exemplified in a definitive study of Peromyscus in the field. Burt pointed out the ever-changing characteristics of home-range area and the consequent absence of boundaries in the usual sense--a finding verified by investigators thereafter. In the studies summarized in this paper, sizes of home ranges of Peromyscus varied within two magnitudes, approximately from 0.1 acre to ten acres, in 34 studies conducted in a variety of habitats from the seaside dunes of Florida to the Alaskan forests. Variation in sizes of home ranges was correlated with both environmental and physiological factors; with habitat it was conspicuous, both in the same and different regions. Food supply also was related to size of home range, both seasonally and in relation to habitat. Home ranges generally were smallest in winter and largest in spring, at the onset of the breeding season. Activity and size also were affected by changes in weather. Activity was least when temperatures were low and nights were bright. Effects of rainfall were variable. Sizes varied according to sex and age; young mice remained in the parents' range until they approached maturity, when they began to travel more widely. Adult males commonly had larger home ranges than females, although there were a number of exceptions. An inverse relationship between population density and size of home range was shown in several studies and probably is the usual relationship. A basic need for activity and exploration also appeared to influence size of home range. Behavior within the home range was discussed in terms of travel patterns, travels in relation to home sites and refuges, territory, and stability of size of home range. Travels within the home range consisted of repeated use of well-worn trails to sites of food, shelter, and refuge, plus more random exploratory travels

  5. Residual radioactivity at the CERN 600 MeV synchro-cyclotron

    NASA Astrophysics Data System (ADS)

    Carbonez, P.; La Torre, F. P.; Michaud, R.; Silari, M.

    2012-12-01

    The 600 MeV synchro-cyclotron (SC) was the first accelerator that came into operation at CERN in 1957. It provided beams for CERN's first particle and nuclear physics experiments and operated for 33 years until it was shut down in 1990. In view of a planned partial decommissioning of the facility, a range of measurements were carried out to evaluate the levels of residual radioactivity in the accelerator and its surrounding after about 20 years of cooling time. Gamma spectrometry measurements were performed on 113 samples collected inside the three floors of the accelerator vault, on the cyclotron itself and on concrete samples taken from various parts of the building walls, up to a depth of 50 cm in the shield. About 40% of all samples contain traces of neutron-induced radionuclides, mainly 60Co (in metals), 133Ba, 137Cs, 152Eu and 154Eu (in concrete). Values of specific activities range from 5 mBq/g to 781 Bq/g. The maximum activity induced in concrete was observed at the depth of 40 cm in the wall near the cyclotron extraction channel. The laboratory measurements were supplemented by in-situ gamma spectrometry performed with the ISOCS system. A complete dose rate survey was also performed yielding isodose maps of the three levels of the building. The isotope production and the residual radioactivity in the barite walls of the SC bunker were simulated with the FLUKA and JEREMY codes in use at CERN for predicting residual radioactivity in activated accelerator components, and the results compared with the gamma spectrometry data. A detailed comparison of calculated and measured specific activities shows generally good agreement, to within a factor 2 in most cases. These results serve as indirect validation of the capabilities of these codes to correctly predict residual radioactivity with only a very approximate knowledge of the irradiation profile and after a very long (20 years) cooling time. Overall the results provided in this paper may be of use for

  6. Neutron scattering measurements in {sup 197}Au from 850 keV to 2.0 MeV

    SciTech Connect

    O`Connor, M.; Chen, J.; Egan, J.J.

    1995-10-01

    Differential elastic and inelastic neutron scattering cross-sections for low lying levels in {sup 197}Au have been measured for incident neutron energies of 1.0 MeV, 1.5 MeV and 2.0 MeV. In addition, the total neutron cross sections in {sup 197}Au was measured from 850 keV to 1.5 MeV. For both experiments the UML 5.5 MV Van-de-Graaff accelerator with a Mobley post acceleration compression system, produced subnanosecond proton pulses which generated neutrons via the {sup 7}Li(p,n) {sup 7}Be reaction.

  7. Radiobiological intercomparison of the 160 MeV and 230 MeV proton therapy beams at the Harvard Cyclotron Laboratory and at Massachusetts General Hospital.

    PubMed

    Wouters, Bradly G; Skarsgard, Lloyd D; Gerweck, Leo E; Carabe-Fernandez, Alejandro; Wong, Michelle; Durand, Ralph E; Nielson, Deanna; Bussiere, Marc R; Wagner, Miles; Biggs, Peter; Paganetti, Harald; Suit, Herman D

    2015-02-01

    The purpose of this study was to determine the relative biological effectiveness (RBE) along the axis of two range-modulated proton beams (160 and 230 MeV). Both the depth and the dose dependence of RBE were investigated. Chinese hamster V79-WNRE cells, suspended in medium containing gelatin and cooled to 2 °C, were used to obtain complete survival curves at multiple positions throughout the entrance and 10 cm spread-out Bragg peak (SOBP). Simultaneous measurements of the survival response to (60)Co gamma rays served as the reference data for the proton RBE determinations. For both beams the RBE increased significantly with depth in the 10 cm SOBP, particularly in the distal half of the SOBP, then rose even more sharply at the distal edge, the most distal position measured. At a 4 Gy dose of gamma radiation (S = 0.34) the average RBE values for the entrance, proximal half, distal half and distal edge were 1.07 ± 0.01, 1.10 ± 0.01, 1.17 ± 0.01 and 1.21 ± 0.01, respectively, and essentially the same for both beams. At a 2 Gy dose of gamma radiation (S = 0.71) the average RBE values rose to 1.13 ± 0.03, 1.15 ± 0.02, 1.26 ± 0.02 and 1.30 ± 0.02, respectively, for the same four regions of the SOBP. The difference between the 4 Gy and 2 Gy RBE values reflects the dose dependence of RBE as measured in these V79-WNRE cells, which have a low α/β value, as do other widely used cell lines that also show dose-dependent RBE values. Late-responding tissues are also characterized by low α/β values, so it is possible that these cell lines may be predictive for the response of such tissues (e.g., spinal cord, optic nerve, kidney, liver, lung). However, in the very small number of studies of late-responding tissues performed to date there appears to be no evidence of an increased RBE for protons at low doses. Similarly, RBE measurements using early responding in vivo systems (mostly mouse jejunum, an early-responding tissue which has a large α/β ∼ 10 Gy) have

  8. Experimental studies of H13CO+ recombining with electrons at energies between 2-50,000 meV.

    PubMed

    Hamberg, Mathias; Kashperka, Iryna; Thomas, Richard D; Roueff, Evelyne; Zhaunerchyk, Vitali; Danielsson, Mathias; af Ugglas, Magnus; Österdah, Fabian; Vigren, Erik; Kaminska, Magdalena; Källberg, Anders; Simonsson, Ansgar; Paal, Andras; Gerin, Maryvonne; Larsson, Mats; Geppert, Wolf D

    2014-08-01

    An investigation into the dissociative recombination process for H(13)CO(+) using merged ion-electron beam methods has been performed at the heavy ion storage ring CRYRING, Stockholm, Sweden. We have measured the branching fractions of the different product channels at ∼ 0 eV collision energy to be the following: CO + H 87 ± 2%, OH + C 9 ± 2%, and O + CH 4 ± 2%. The formation of electronically excited CO in the dominant reaction channel has also been studied, and we report the following tentative branching fractions for the different CO product electronic states: CO(X (1)Σ(+)) + H, 54 ± 10%; CO(a (3)Π) + H, 23 ± 4%; and CO(a' (3)Σ(+)) + H, 23 ± 4%. The absolute cross section between ∼ 2-50 000 meV was measured and showed resonance structures between 3 and 15 eV. The cross section was fitted in the energy range relevant to astrophysics, i.e., between 1 and 300 meV, and was found to follow the expression σ = 1.3 ± 0.3 × 10(-16) E(-1.29 ± 0.05) cm(2) and the corresponding thermal rate constant was determined to be k(T) = 2.0 ± 0.4 × 10(-7)(T/300)(-0.79 ± 0.05) cm(3) s(-1). Radioastronomical observations with the IRAM 30 m telescope of HCO(+) toward the Red Rectangle yielded an upper column density limit of 4 × 10(11) cm(-2) of HCO(+) at the 1σ level in that object, indicating that previous claims that the dissociative recombination of HCO(+) plays an important role in the production of excited CO molecules emitting the observed Cameron bands in that object are not supported.

  9. Decommissioning procedures for an 11 MeV self-shielded medical cyclotron after 16 years of working time.

    PubMed

    Calandrino, R; del Vecchio, A; Savi, A; Todde, S; Griffoni, V; Brambilla, S; Parisi, R; Simone, G; Fazio, F

    2006-06-01

    The present article describes the decommissioning of a compact, self-shielded, 11 MeV medical cyclotron. A Monte Carlo simulation of the possible nuclear reactions was performed in order to plan the decommissioning activities. In the course of the cyclotron dismantling, cyclotron components, shields, and floor concrete samples were measured. Residual activities were analyzed with a Ge(Li) detector and compared with simulation data. Doses to staff involved in the decommissioning procedure were monitored by individual TL dosimeters. The simulations identified five radioactive nuclides in shields and floor concrete: 55Fe and 45Ca (beta emitters, total specific activity: 2.29 x 10(4) Bq kg) and 152Eu, 154Eu, 60Co (gamma emitters, total specific activity: 1.62 x 10(3) Bq kg-1). Gamma-ray spectrometry confirmed the presence of gamma emitters, corresponding to a total specific activity of 3.40 x 10(2) Bq kg-1. The presence of the radioisotope 124Sb in the lead contained in the shield structure, corresponding to a simulated specific activity of 9.38 x 10(3) Bq kg-1, was experimentally confirmed. The measured dose from external exposure of the involved staff was <20 muSv, in accordance with the expected range of values between 10 and 20 muSv. The measured dose from intake was negligible. Finally, the decommissioning of the 11 MeV cyclotron does not represent a risk for the involved staff, but due to the presence of long-lived radioisotopes, the cyclotron components are to be treated as low level radioactive waste and stored in an authorized storage area. PMID:16691108

  10. SNOWY RANGE WILDERNESS, WYOMING.

    USGS Publications Warehouse

    Houston, Robert S.; Bigsby, Philip R.

    1984-01-01

    A mineral survey of the Snowy Range Wilderness in Wyoming was undertaken and was followed up with more detailed geologic and geochemical surveys, culminating in diamond drilling of one hole in the Snowy Range Wilderness. No mineral deposits were identified in the Snowy Range Wilderness, but inasmuch as low-grade uranium and associated gold resources were identified in rocks similar to those of the northern Snowy Range Wilderness in an area about 5 mi northeast of the wilderness boundary, the authors conclude that the northern half of the wilderness has a probable-resource potential for uranium and gold. Closely spaced drilling would be required to completely evaluate this mineral potential. The geologic terrane precludes the occurrence of fossil fuels.

  11. Monte Carlo simulation of electron beam transport in graphite for composite application from MeV down to eV

    NASA Astrophysics Data System (ADS)

    Leger, J.; Yousfi, M.; Eichwald, O.; Loiseau, J. F.; Held, B.

    2005-04-01

    A Monte Carlo method, based on the treatment of the individual interactions and using the null collision technique to reduce the computation time, has been developed for the simulation of electron-matter interactions and validated for the case of graphite. Results describing the electron energy behaviour (energy deposition, energy distribution, electron density, etc) have been obtained for various initial energies (1 MeV, 500 keV, 100 keV, 10 keV and 1.6 keV) of the electron beam down to several lower limit or cutoff energies (100 keV, 25 keV, 5 keV and 10 eV). The specificity of the present simulation is, therefore, to cover quite a wide energy range (e.g. from 1 MeV down to 10 eV) during the electron transport in graphite. The electron-matter collision cross sections needed for the simulation over such an energy range (from 10 eV up to 1 MeV) are given. At higher energies, the elastic and inner-shell inelastic collision cross sections take into account the relativistic effects, and the photons resulting from the bremsstrahlung processes are considered as electron sources when they undergo Compton and photoelectric processes. At intermediate and low energy ranges, the inelastic collision cross sections for the conduction band excitations are obtained from a classical dielectric function model. The significant effect of the lowering of the cutoff energy on the deposited energy is emphasized, while the contribution to the deposited energy of the photon interactions is shown to be quite low in the case of the present initial beam energies.

  12. Mu-2 ranging

    NASA Technical Reports Server (NTRS)

    Martin, W. L.; Zygielbaum, A. I.

    1977-01-01

    The Mu-II Dual-Channel Sequential Ranging System designed as a model for future Deep Space Network ranging equipment is described. A list of design objectives is followed by a theoretical explanation of the digital demodulation techniques first employed in this machine. Hardware and software implementation are discussed, together with the details relating to the construction of the device. Two appendixes are included relating to the programming and operation of this equipment to yield the maximum scientific data.

  13. Positron-electron decay of 28Si at an excitation energy of 50 MeV

    NASA Astrophysics Data System (ADS)

    Buda, A.; Bacelar, J. C.; Balanda, A.; van der Ploeg, H.; Sujkowski, Z.; van der Woude, A.

    1993-03-01

    The electron-position pair decay of 28Si at 50 MeV excitation produced by the isospin T=0 (α + 24Mg) and the mixed isospin T=0,1 (3He + 25Mg) reactions has been studied using a special designed Positron-Electron pair spectrometer PEPSI.

  14. Flare vs. Shock Acceleration of >100 MeV Protons in Large Solar Particle Events

    NASA Astrophysics Data System (ADS)

    Cliver, Edward W.

    2016-05-01

    Recently several studies have presented correlative evidence for a significant-to-dominant role for a flare-resident process in the acceleration of high-energy protons in large solar particle events. In one of these investigations, a high correlation between >100 MeV proton fluence and 35 GHz radio fluence is obtained by omitting large proton events associated with relatively weak flares; these outlying events are attributed to proton acceleration by shock waves driven by coronal mass ejections (CMEs). We argue that the strong CMEs and associated shocks observed for proton events on the main sequence of the scatter plot are equally likely to accelerate high-energy protons. In addition, we examine ratios of 0.5 MeV electron to >100 MeV proton intensities in large SEP events, associated with both well-connected and poorly-connected solar eruptions, to show that scaled-up versions of the small flares associated with classical impulsive SEP events are not significant accelerators of >100 MeV protons.

  15. Residual Nuclei Production in the reaction {sup 136}Xe+ deuterium at 500 A MeV

    SciTech Connect

    Alcantara-Nunez, J. A.; Benlliure, J.; Perez-Loureiro, D.; Casarejos, E.; Fernandez Ordonez, M.; Pereira, J.; Armbruster, P.; Enqvist, T.; Henzl, V.; Henzlova, D.; Kelic, A.; Pleskac, R.; Ricciardi, M. V.; Schmidt, K.-H.; Schmitt, C.; Yordanov, O.; Audouin, L.; Bernas, M.; Lafriaskh, A.; Stephan, C.

    2010-04-26

    More than six hundred nuclei produced in the fragmentation of {sup 136}Xe projectiles at 500 A MeV on a liquid deuterium target were identified using inverse kinematics at the GSI Fragment Separator (FRS). These data are relevant for understanding of spallation reactions.

  16. Proton irradiation of conventional and lithium solar cells - 11-37 MeV

    NASA Technical Reports Server (NTRS)

    Anspaugh, B. E.; Carter, J. R.

    1974-01-01

    Conventional n/p and lithium solar cells were irradiated with 11- to 37-MeV protons. The energy dependence of the solar cell degradation, calculated from electrical parameters and lifetime measurements, is shown to be very slight. Damage coefficients for the n/p cells are calculated. Annealing characteristics of both the lithium cells and the n/p cells are presented.

  17. Voltage holding study of 1 MeV accelerator for ITER neutral beam injector.

    PubMed

    Taniguchi, M; Kashiwagi, M; Umeda, N; Dairaku, M; Takemoto, J; Tobari, H; Tsuchida, K; Yamanaka, H; Watanabe, K; Kojima, A; Hanada, M; Sakamoto, K; Inoue, T

    2012-02-01

    Voltage holding test on MeV accelerator indicated that sustainable voltage was a half of that of ideal quasi-Rogowski electrode. It was suggested that the emission of the clumps is enhanced by a local electric field concentration, which leads to discharge initiation at lower voltage. To reduce the electric field concentration in the MeV accelerator, gaps between the grid supports were expanded and curvature radii at the support corners were increased. After the modifications, the accelerator succeeded in sustaining -1 MV in vacuum without beam acceleration. However, the beam energy was still limited at a level of 900 keV with a beam current density of 150 A∕m(2) (346 mA) where the 3 × 5 apertures were used. Measurement of the beam profile revealed that deflection of the H(-) ions was large and a part of the H(-) ions was intercepted at the acceleration grid. This causes high heat load on the grids and the breakdowns during beam acceleration. To suppress the direct interception, new grid system was designed with proper aperture displacement based on a 3D beam trajectory analysis. As the result, the beam deflection was compensated and the voltage holding during the beam acceleration was improved. Beam parameter of the MeV accelerator was increased to 980 keV, 185 A∕m(2) (427 mA), which is close to the requirement of ITER accelerator (1 MeV, 200 A∕m(2)).

  18. DPA damage analysis for 14-MeV neutrons on PFC materials

    NASA Astrophysics Data System (ADS)

    Kim, Dong-woo; Lee, Bo-young; Ko, Seung-kook; Kim, Hee-soo; Noh, Seung-jung

    2015-06-01

    The dpa (displacement per atom) damage for 14-MeV neutron in a pfc materials was simulated using MCNPX/SPECTER code. The dpa values in the main components of the structural material SS316L, Fe, Cr and Ni, were calculated to analyze the effect of nuclear damage. According to the neutron wall load for ITER design base, a neutron flux of 3.5 × 1013 neutrons/cm2·sec was applied. The simulated dpa values were found to be as 3.0 dpa/fpy for Fe, 2.9 dpa/fpy for Cr and 3.1 dpa/fpy for Ni. For practical experiments, the simulated dpa values due to the irradiation damage of 17-MeV protons were found to be as 0.67 dpa at the peak and 0.05 at the surface for SS316L using by SRIM code at the same fluence. For the 17-MeV proton irradiation, the Bragg peak appears at a 0.64-mm depth. Also, SS316L specimens irradiated by a 17-MeV proton beam with a fluence of 1016 protons/cm2 were analyzed by using transmission electron microscopy.

  19. Properties of 16C(6.11 MeV) and its mirror in 16Ne

    NASA Astrophysics Data System (ADS)

    Fortune, H. T.

    2016-07-01

    From previous data for the reaction 14C(t ,p )16C , I have extracted a width of 32.6(5) keV for the strong state at Ex=6.11 MeV . Here, I examine its likely Jπ and configuration. The predicted width of its mirror in 16Ne is estimated to be about 260 keV.

  20. Deuteron-proton breakup reaction at Ed=7.4 MeV

    NASA Astrophysics Data System (ADS)

    Kröger, H.; Nachabe, A. M.; Slobodrian, R. J.

    1986-04-01

    The reaction d+p-->p+p+n is investigated at Elabd=7.4 MeV. Calculations of the cross section are compared with recent kinematically complete measurements. The Coulomb potential is taken fully into account in the calculations based on the strong approximation of Mo/ller wave operator approach.

  1. The 2-MEV Model: Constancy of Adolescent Environmental Values within an 8-Year Time Frame

    ERIC Educational Resources Information Center

    Bogner, F. X.; Johnson, B.; Buxner, S.; Felix, L.

    2015-01-01

    The 2-MEV model is a widely used tool to monitor children's environmental perception by scoring individual values. Although the scale's validity has been confirmed repeatedly and independently as well as the scale is in usage within more than two dozen language units all over the world, longitudinal properties still need clarification. The purpose…

  2. Measurement of the. pi. d. -->. pp reaction at T/sub. pi. / = 65 MeV

    SciTech Connect

    Ottermann, C.R.; Boschitz, E.T.; Gyles, W.; List, W.; Tacik, R.; Mango, S.; Konter, J.A.; van den Brandt, B.; Smith, G.R.

    1986-05-01

    The vector analyzing power iT/sub 11/ has been measured for the ..pi..d..-->..pp reaction at an incident pion energy of 65 MeV, using a vector polarized deuteron target. The data are compared with predictions from coupled channels, Faddeev, and perturbation theory calculations.

  3. Measurement of cross sections for the 63Cu(alpha,gamma)67Ga reaction from 5.9-8.7 MeV

    SciTech Connect

    Basunia, M. Shamsuzzoha; Norman, Eric B.; Shugart, Howard A.; Smith, Alan R.; Dolinski, Michelle J.; Quiter, Brian J.

    2004-09-23

    We have measured cross sections for the 63Cu(alpha,gamma)67Ga reaction in the 5.9-8.7 MeV energy range using an activation technique. Natural Cu foils were bombarded with alpha beams from the 88 Cyclotron at Lawrence Berkeley National Laboratory (LBNL). Activated foils were counted using gamma spectrometry system at LBNL's Low Background Facility. The 63Cu(alpha,gamma)67Ga cross-sections were determined and compared with the latest NON-SMOKER theoretical values. Experimental cross sections were found to be in agreement with theoretical values.

  4. Spectroscopy of the {sup 29}Si(p,{gamma}) reaction for E{sub p}=1.00{endash}1.75 MeV

    SciTech Connect

    Vavrina, G.A.; Bybee, C.R.; Mitchell, G.E.; Moore, E.F.; Shriner, J.D.; Bilpuch, E.G.; Wallace, P.M.; Westerfeldt, C.R.; Shriner, J.F. , Jr.

    1997-03-01

    The {sup 29}Si(p,{gamma}) reaction has been studied in the range E{sub p}=1.00{endash}1.75 MeV. Three previously unknown states in {sup 30}P were identified, and one state previously assigned to {sup 30}P was identified as a state in {sup 14}N. Gamma-ray strengths were determined for the three new levels, and branching ratios were measured for 17 resonances. Revised J{sup {pi}};T assignments were made for nine of these states. {copyright} {ital 1997} {ital The American Physical Society}

  5. Neutron production at 0{degree} from the {sup 40}Ca+H reaction at E{sub lab}=357A and 565A MeV

    SciTech Connect

    Tuve, C.; Albergo, S.; Boemi, D.; Caccia, Z.; Costa, S.; Insolia, A.; Potenza, R.; Reito, S.; Romanski, J.; Russo, G.V.; Cronqvist, M.; Lindstrom, P.J.; Chen, C.; Guzik, T.G.; Tull, C.E.; Wefel, J.P.; Crawford, H.J.; Engelage, J.; Greiner, L.; Knott, C.N.; Waddington, C.J.; Webber, W.R.; Soutoul, A.; Testard, O.; Mitchell, J.W.

    1997-08-01

    Neutrons produced in the {sup 40}Ca+H reaction at E{sub lab}=357A and 565A MeV have been detected using a three-module version of the multifunctional neutron spectrometer MUFFINS. The detector covered a narrow angular range around the beam in the forward direction (0{degree}{minus}3.2{degree}). Semi-inclusive neutron production cross sections, at the two energies, are reported together with neutron energy spectra, angular, rapidity, and transverse momentum distributions. Comparison with a Boltzmann-Nordheim-Vlasov approach + phase space coalescence model is discussed. {copyright} {ital 1997} {ital The American Physical Society}

  6. Studies of the response of CR-39 track detectors to protons from a 3 MeV Van de Graaff accelerator

    NASA Astrophysics Data System (ADS)

    Bernardi, L.; Cecchi, A.; Gori, C.; Lucarelli, F.; Renzi, R.

    1991-01-01

    A Van de Graaff proton accelerator was tested for its application to the study of CR-39 SSNTD response to accelerated protons. The energies of the proton beams ranged from 0.2 to 2.3 MeV. Two different beam angles of incidence were taken into consideration for each proton energy (i.e. normal incidence and 45°). The complete procedure for the irradiation of a CR-39 sample required relatively little time and the results obtained — in agreement with others as reported in the literature — demonstrated that the Van de Graaff proton accelerator can find a useful application to the problem of neutron dosimetry using SSNTDs.

  7. Laser Ranging Simulation Program

    NASA Technical Reports Server (NTRS)

    Piazolla, Sabino; Hemmati, Hamid; Tratt, David

    2003-01-01

    Laser Ranging Simulation Program (LRSP) is a computer program that predicts selected aspects of the performances of a laser altimeter or other laser ranging or remote-sensing systems and is especially applicable to a laser-based system used to map terrain from a distance of several kilometers. Designed to run in a more recent version (5 or higher) of the MATLAB programming language, LRSP exploits the numerical and graphical capabilities of MATLAB. LRSP generates a graphical user interface that includes a pop-up menu that prompts the user for the input of data that determine the performance of a laser ranging system. Examples of input data include duration and energy of the laser pulse, the laser wavelength, the width of the laser beam, and several parameters that characterize the transmitting and receiving optics, the receiving electronic circuitry, and the optical properties of the atmosphere and the terrain. When the input data have been entered, LRSP computes the signal-to-noise ratio as a function of range, signal and noise currents, and ranging and pointing errors.

  8. 1000 MeV Proton beam therapy facility at Petersburg Nuclear Physics Institute Synchrocyclotron

    NASA Astrophysics Data System (ADS)

    Abrosimov, N. K.; Gavrikov, Yu A.; Ivanov, E. M.; Karlin, D. L.; Khanzadeev, A. V.; Yalynych, N. N.; Riabov, G. A.; Seliverstov, D. M.; Vinogradov, V. M.

    2006-05-01

    Since 1975 proton beam of PNPI synchrocyclotron with fixed energy of 1000 MeV is used for the stereotaxic proton therapy of different head brain diseases. 1300 patients have been treated during this time. The advantage of high energy beam (1000 MeV) is low scattering of protons in the irradiated tissue. This factor allows to form the dose field with high edge gradients (20%/mm) that is especially important for the irradiation of the intra-cranium targets placed in immediate proximity to the life critical parts of the brain. Fixation of the 6 0mm diameter proton beam at the isodose centre with accuracy of ±1.0 mm, two-dimensional rotation technique of the irradiation provide a very high ratio of the dose in the irradiation zone to the dose at the object's surface equal to 200:1. The absorbed doses are: 120-150 Gy for normal hypophysis, 100-120 Gy for pituitary adenomas and 40-70 Gy for arterio-venous malformation at the rate of absorbed dose up to 50 Gy/min. In the paper the dynamics and the efficiency of 1000 MeV proton therapy treatment of the brain deceases are given. At present time the feasibility study is in progress with the goal to create a proton therapy on Bragg peak by means of the moderation of 1000 MeV proton beam in the absorber down to 200 MeV, energy required for radiotherapy of deep seated tumors.

  9. Acceleration of ampere class H(-) ion beam by MeV accelerator.

    PubMed

    Taniguchi, M; Inoue, T; Umeda, N; Kashiwagi, M; Watanabe, K; Tobari, H; Dairaku, M; Sakamoto, K

    2008-02-01

    The H(-) ion accelerator R&D to realize the international thermonuclear experimental reactor neutral beam is ongoing at Japan Atomic Energy Agency (JAEA). The required performance for the prototype MeV accelerator developed at JAEA is 1 MeV, 500 mA (current density of 200 A/m(2)) H(-) ion beam at the beamlet divergence angle of less than 7 mrad. Up to 2005, 836 keV, 146 A/m(2) H(-) ion beam was successfully accelerated as the highest record of the current density at MeV class energy beams. In the present work, high current negative ion beam acceleration test was performed by increasing the beam extraction apertures from 3 x 3 (9 apertures) to 3 x 5 (15 apertures). By fixing the air leak at the source chamber due to backstream ions as well as the improvement of voltage holding capability by a new fiber reinforced plastic insulator ring, the performance of the MeV accelerator was improved. So far, H(-) ion beam of 320 mA was successfully accelerated up to 796 keV with the beam divergence angle of 5.5 mrad. The accelerated drain current including the electron reaches close to the power supply limit for the MeV test facility. The heat flux by the backstream ion during the above beam acceleration was estimated to be 360 W/cm(2). The Cs leakage to the accelerator during the test campaign (Cs total input of 5.0 g) was 0.26 mg (7.0 microg/cm(2)). This is considered to be the allowable level from the viewpoint of voltage holding. PMID:18315236

  10. Measurement of 181 MeV H- ions stripping cross-sections by carbon stripper foil

    NASA Astrophysics Data System (ADS)

    Saha, P. K.; Yoshimoto, M.; Yamazaki, Y.; Hotchi, H.; Harada, H.; Okabe, K.; Kinsho, M.; Irie, Y.

    2015-03-01

    The stripping cross-sections of 181 MeV H- (negative hydrogen) ions by the carbon stripper foil are measured with good accuracy. The present experiment was carried out at the 3-GeV RCS (Rapid Cycling Synchrotron) of J-PARC (Japan Proton Accelerator Research Complex). The stripping cross-sections for different charge states, also known as electron loss cross-sections of H- ion, are denoted as σ-11, σ-10 and σ01, for both electrons stripping (H- →H+), one-electron stripping (H- →H0) and the 2nd-electron stripping (H0 →H+) proceeding σ-10, respectively. We have established very unique and precise techniques for such measurements so as also to determine a foil stripping efficiency very accurately. The cross-sections σ-11, σ-10 and σ01 are obtained to be (0.002 ± 0.001) ×10-18cm2, (1.580 ± 0.034) ×10-18cm2 and (0.648 ± 0.014) ×10-18cm2, respectively. The presently given cross-sections are newly available experimental results for an incident H- energy below 200 MeV and they are also shown to be consistent with recently proposed energy (1 /β2) scaled cross-sections calculated from the previously measured data at 200 and 800 MeV. The present results have a great importance not only at J-PARC for the upgraded H- beam energy of 400 MeV but also for many new and upgrading similar accelerators, where H- beam energies in most cases are considered to be lower than 200 MeV.

  11. Reconfigurable laser ranging instrument

    NASA Astrophysics Data System (ADS)

    Schneiter, John

    1994-03-01

    This paper describes the design and operation of a fast, flexible, non-contact, eye-safe laser ranging instrument useful in a variety of industrial metrology situations, such as in-process machining control and part inspection. The system has variable computer-controlled standoff and depth of field, and can obtain 3-D images of surfaces within a range of from 1.5 ft to almost 10 ft from the final optical element. The minimum depth of field is about 3.5 in. at 1.5 ft and about 26 in. at the far range. The largest depth of field for which useful data are available is about 41 in. Resolution, with appropriate averaging, is about one part in 4000 of the depth of field, which implies a best case resolution for this prototype of 0.00075 in. System flexibility is achieved by computer controlled relative positioning of optical components.

  12. The range scheduling aid

    NASA Technical Reports Server (NTRS)

    Halbfinger, Eliezer M.; Smith, Barry D.

    1991-01-01

    The Air Force Space Command schedules telemetry, tracking and control activities across the Air Force Satellite Control network. The Range Scheduling Aid (RSA) is a rapid prototype combining a user-friendly, portable, graphical interface with a sophisticated object-oriented database. The RSA has been a rapid prototyping effort whose purpose is to elucidate and define suitable technology for enhancing the performance of the range schedulers. Designing a system to assist schedulers in their task and using their current techniques as well as enhancements enabled by an electronic environment, has created a continuously developing model that will serve as a standard for future range scheduling systems. The RSA system is easy to use, easily ported between platforms, fast, and provides a set of tools for the scheduler that substantially increases his productivity.

  13. Western Aeronautical Test Range

    NASA Technical Reports Server (NTRS)

    Sakahara, Robert D.

    2008-01-01

    This viewgraph presentation reviews the work of the Western Aeronautical Test Range (WATR). NASA's Western Aeronautical Test Range is a network of facilities used to support aeronautical research, science missions, exploration system concepts, and space operations. The WATR resides at NASA's Dryden Flight Research Center located at Edwards Air Force Base, California. The WATR is a part of NASA's Corporate Management of Aeronautical Facilities and funded by the Strategic Capability Asset Program (SCAP). Maps show the general location of the WATR area that is used for aeronautical testing and evaluation. The products, services and facilities of WATR are discussed,

  14. Himalayan Mountain Range, India

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Snow is present the year round in most of the high Himalaya Mountain Range (33.0N, 76.5E). In this view taken at the onset of winter, the continuous snow line can be seen for hundreds of miles along the south face of the range in the Indian states of Punjab and Kashmir. The snow line is at about 12,000 ft. altitude but the deep Cenab River gorge is easily delineated as a break along the south edge of the snow covered mountains. '

  15. Satellite Laser Ranging operations

    NASA Technical Reports Server (NTRS)

    Pearlman, Michael R.

    1994-01-01

    Satellite Laser Ranging (SLR) is currently providing precision orbit determination for measurements of: 1) Ocean surface topography from satellite borne radar altimetry, 2) Spatial and temporal variations of the gravity field, 3) Earth and ocean tides, 4) Plate tectonic and regional deformation, 5) Post-glacial uplift and subsidence, 6) Variations in the Earth's center-of-mass, and 7) Variations in Earth rotation. SLR also supports specialized programs in time transfer and classical geodetic positioning, and will soon provide precision ranging to support experiments in relativity.

  16. Satellite laser ranging

    NASA Astrophysics Data System (ADS)

    Osorio, J. P.

    1992-03-01

    Laser ranging to satellites is one of the most precise methods for positio ning on the surface of the Earth. Reference is made to the need for precise posi tioning and to the improvement brought by the use of space techniques. Satellite Laser Ranging system is then described and in view of the high precision of the results derived from its measurements comments are made to some of the more important applications: high precision networks tectonic plate motion polar motion and earth''s rotation. Finally plans for system improvement in the near future are also presented.

  17. Near-earth injection of MeV electrons associated with intense dipolarization electric fields: Van Allen Probes observations

    DOE PAGES

    Dai, Lei; Wang, Chi; Duan, Suping; He, Zhaohai; Wygant, John R.; Cattell, Cynthia A.; Tao, Xin; Su, Zhenpeng; Kletzing, Craig; Baker, Daniel N.; et al

    2015-08-10

    Substorms generally inject tens to hundreds of keV electrons, but intense substorm electric fields have been shown to inject MeV electrons as well. An intriguing question is whether such MeV electron injections can populate the outer radiation belt. Here we present observations of a substorm injection of MeV electrons into the inner magnetosphere. In the premidnight sector at L~5.5, Van Allen Probes (Radiation Belt Storm Probes)-A observed a large dipolarization electric field (50 mV/m) over ~40 s and a dispersionless injection of electrons up to ~3 MeV. Pitch angle observations indicated betatron acceleration of MeV electrons at the dipolarization front.more » Corresponding signals of MeV electron injection were observed at LANL-GEO, THEMIS-D, and GOES at geosynchronous altitude. Through a series of dipolarizations, the injections increased the MeV electron phase space density by 1 order of magnitude in less than 3 h in the outer radiation belt (L > 4.8). Our observations provide evidence that deep injections can supply significant MeV electrons.« less

  18. Near-earth injection of MeV electrons associated with intense dipolarization electric fields: Van Allen Probes observations

    SciTech Connect

    Dai, Lei; Wang, Chi; Duan, Suping; He, Zhaohai; Wygant, John R.; Cattell, Cynthia A.; Tao, Xin; Su, Zhenpeng; Kletzing, Craig; Baker, Daniel N.; Li, Xinlin; Malaspina, David; Blake, J. Bernard; Fennell, Joseph; Claudepierre, Seth; Turner, Drew L.; Reeves, Geoffrey D.; Funsten, Herbert O.; Spence, Harlan E.; Angelopoulos, Vassilis; Fruehauff, Dennis; Chen, Lunjin; Thaller, Scott; Breneman, Aaron; Tang, Xiangwei

    2015-08-10

    Substorms generally inject tens to hundreds of keV electrons, but intense substorm electric fields have been shown to inject MeV electrons as well. An intriguing question is whether such MeV electron injections can populate the outer radiation belt. Here we present observations of a substorm injection of MeV electrons into the inner magnetosphere. In the premidnight sector at L~5.5, Van Allen Probes (Radiation Belt Storm Probes)-A observed a large dipolarization electric field (50 mV/m) over ~40 s and a dispersionless injection of electrons up to ~3 MeV. Pitch angle observations indicated betatron acceleration of MeV electrons at the dipolarization front. Corresponding signals of MeV electron injection were observed at LANL-GEO, THEMIS-D, and GOES at geosynchronous altitude. Through a series of dipolarizations, the injections increased the MeV electron phase space density by 1 order of magnitude in less than 3 h in the outer radiation belt (L > 4.8). Our observations provide evidence that deep injections can supply significant MeV electrons.

  19. RADIO RANGING DEVICE

    DOEpatents

    Bogle, R.W.

    1960-11-22

    A description is given of a super-regenerative oscillator ranging device provided with radiating and receiving means and being capable of indicating the occurrence of that distance between itself and a reflecting object which so phases the received echo of energy of a preceding emitted oscillation that the intervals between oscillations become uniform.

  20. Agriculture, forest, and range

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The findings and recommendations of the panel for developing a satellite remote-sensing global information system in the next decade are reported. User requirements were identified in five categories: (1) cultivated crops, (2) land resources, (3)water resources, (4)forest management, and (5) range management. The benefits from the applications of satellite data are discussed.

  1. Agriculture, forestry, range resources

    NASA Technical Reports Server (NTRS)

    Crea, W. J.

    1974-01-01

    In the area of crop specie identification, it has been found that temporal data analysis, preliminary stratification, and unequal probability analysis were several of the factors that contributed to high identification accuracies. Single data set accuracies on fields of greater than 80,000 sq m (20 acres) are in the 70- to 90-percent range; however, with the use of temporal data, accuracies of 95 percent have been reported. Identification accuracy drops off significantly on areas of less than 80,000 sq m (20 acres) as does measurement accuracy. Forest stratification into coniferous and deciduous areas has been accomplished to a 90- to 95-percent accuracy level. Using multistage sampling techniques, the timber volume of a national forest district has been estimated to a confidence level and standard deviation acceptable to the Forest Service at a very favorable cost-benefit time ratio. Range specie/plant community vegetation mapping has been accomplished at various levels of success (69- to 90-percent accuracy). However, several investigators have obtained encouraging initial results in range biomass (forage production) estimation and range readiness predictions. Soil association map correction and soil association mapping in new area appear to have been proven feasible on large areas; however, testing in a complex soil area should be undertaken.

  2. Agriculture, forestry, range resources

    NASA Technical Reports Server (NTRS)

    Macdonald, R. B.

    1974-01-01

    The necessary elements to perform global inventories of agriculture, forestry, and range resources are being brought together through the use of satellites, sensors, computers, mathematics, and phenomenology. Results of ERTS-1 applications in these areas, as well as soil mapping, are described.

  3. Institutional Long Range Planning.

    ERIC Educational Resources Information Center

    Caldwell Community Coll. and Technical Inst., Lenoir, NC.

    Long-range institutional planning has been in effect at Caldwell Community College and Technical Institute since 1973. The first step in the process was the identification of planning areas: administration, organization, educational programs, learning resources, student services, faculty, facilities, maintenance/operation, and finances. The major…

  4. STDN ranging equipment

    NASA Technical Reports Server (NTRS)

    Jones, C. E.

    1975-01-01

    Final results of the Spaceflight Tracking and Data Network (STDN) Ranging Equipment program are summarized. Basic design concepts and final design approaches are described. Theoretical analyses which define requirements and support the design approaches are presented. Design verification criteria are delineated and verification test results are specified.

  5. Laser ranging data analysis

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Center for Space Research efforts have focused on the near real-time analysis of Lageos laser ranging data and on the production of predictive ephemerides. The data are analyzed in terms of range bias, time bias, and internal precision, and estimates for the Earth orientation parameters X(sub p), Y(sub p) and UT1 are obtained. The results of these analyses are reported in a variety of formats. In addition several additional stations began sending not only quick-look observations but also normal points created on-site with new software. These normal points are transmitted in a new standard format different from either current quick-look or MERIT-II full-rate formats. Thus new preprocessing software was written and successfully tested on these data. Inspection of the Bendix produced Lageos full-rate normal points continued, with detailed analyses and filtering of all 1991 A and B release normal points for Lageos through the beginning of 1992. A summary of the combined full-rate and quick-look normal point data set created for 1991 is provided. New long-term ephemerides for Lageos satellite, as well as for Etalon-1 and Etalon-2 (the so-called high satellites used for laser ranging) were produced and distributed to the network stations in cooperation with the Crustal Dynamics Project and Eurolas. These predictions are used by essentially every laser ranging site obtaining regular returns from any of these three satellites.

  6. Front Range Branch Officers

    NASA Astrophysics Data System (ADS)

    The Front Range Branch of AGU has installed officers for 1990: Ray Noble, National Center for Atmospheric Research, chair; Sherry Oaks, U.S. Geological Survey, chair-elect; Howard Garcia, NOAA, treasurer; Catharine Skokan, Colorado School of Mines, secretary. JoAnn Joselyn of NOAA is past chair. Members at large are Wallace Campbell, NOAA; William Neff, USGS; and Stephen Schneider, NCAR.

  7. Fact Sheet: Range Complex

    NASA Technical Reports Server (NTRS)

    Cornelson, C.; Fretter, E.

    2004-01-01

    NASA Ames has a long tradition in leadership with the use of ballistic ranges and shock tubes for the purpose of studying the physics and phenomena associated with hypervelocity flight. Cutting-edge areas of research run the gamut from aerodynamics, to impact physics, to flow-field structure and chemistry. This legacy of testing began in the NACA era of the 1940's with the Supersonic Free Flight Tunnel, and evolved dramatically up through the late 1950s with the pioneering work in the Ames Hypersonic Ballistic Range. The tradition continued in the mid-60s with the commissioning of the three newest facilities: the Ames Vertical Gun Range (AVGR) in 1964, the Hypervelocity Free Flight Facility (HFFF) in 1965 and the Electric Arc Shock Tube (EAST) in 1966. Today the Range Complex continues to provide unique and critical testing in support of the Nation's programs for planetary geology and geophysics; exobiology; solar system origins; earth atmospheric entry, planetary entry, and aerobraking vehicles; and various configurations for supersonic and hypersonic aircraft.

  8. Electric vehicles: Driving range

    NASA Astrophysics Data System (ADS)

    Kempton, Willett

    2016-09-01

    For uptake of electric vehicles to increase, consumers' driving-range needs must be fulfilled. Analysis of the driving patterns of personal vehicles in the US now shows that today's electric vehicles can meet all travel needs on almost 90% of days from a single overnight charge.

  9. Mobile satellite ranging

    NASA Technical Reports Server (NTRS)

    Silverberg, E. C.

    1978-01-01

    A brief review of the constraints which have limited satellite ranging hardware and an outline of the steps which are underway to improve the status of the equipment in this area are given. In addition, some suggestions are presented for the utilization of newer instruments and for possible future research and development work in this area.

  10. MeV per nucleon ion irradiation of nuclear materials with high energy synchrotron X-ray characterization

    NASA Astrophysics Data System (ADS)

    Pellin, M. J.; Yacout, Abdellatif M.; Mo, Kun; Almer, Jonathan; Bhattacharya, S.; Mohamed, Walid; Seidman, D.; Ye, Bei; Yun, D.; Xu, Ruqing; Zhu, Shaofei

    2016-04-01

    The combination of MeV/Nucleon ion irradiation (e.g. 133 MeV Xe) and high energy synchrotron x-ray characterization (e.g. at the Argonne Advanced Photon Source, APS) provides a powerful characterization method to understand radiation effects and to rapidly screen materials for the nuclear reactor environment. Ions in this energy range penetrate ∼10 μm into materials. Over this range, the physical interactions vary (electronic stopping, nuclear stopping and added interstitials). Spatially specific x-ray (and TEM and nanoindentation) analysis allow individual quantification of these various effects. Hard x-rays provide the penetration depth needed to analyze even nuclear fuels. Here, this combination of synchrotron x-ray and MeV/Nucleon ion irradiation is demonstrated on U-Mo fuels. A preliminary look at HT-9 steels is also presented. We suggest that a hard x-ray facility with in situ MeV/nucleon irradiation capability would substantially accelerate the rate of discovery for extreme materials.

  11. New excitation functions for proton induced reactions on natural titanium, nickel and copper up to 70 MeV

    NASA Astrophysics Data System (ADS)

    Garrido, E.; Duchemin, C.; Guertin, A.; Haddad, F.; Michel, N.; Métivier, V.

    2016-09-01

    New excitation functions for proton induced nuclear reactions on natural titanium, nickel and copper were measured, using the stacked-foil technique and gamma spectrometry, up to 70 MeV. The experimental cross sections were measured using the Ti-nat(p,x) V-48, Ni-nat(p,x) Ni-57 and Cu-nat(p,x) Zn-62,Co-56 monitor reactions recommended by the International Atomic Energy Agency (IAEA), depending on the investigated energy range. Data have been extracted for the Ti-nat(p,x) Sc-43,44m,46,47,48, V-48, K-42,43, Ni-nat(p,x) Ni-56,57, Co-55,56,57,58, Mn-52,54, Cu-nat(p,x) Cu-61,64, Ni-57, Co-56,57,58,60, Zn-62,65, Mn-54 reactions. Our results are discussed and compared to the existing ones as well as with the TALYS code version 1.6 calculations using default models. Our experimental data are in overall good agreement with the literature. TALYS is able to reproduce, in most cases, the experimental trend. Our new experimental results allow to expand our knowledge on these excitation functions, to confirm the existing trends and to give additional values on a large energy range. This work is in line with the new Coordinated Research Project (CRP) launched by the IAEA to expand the database of monitor reactions.

  12. The radial diffusion coefficient of 1.3 - 2.3 MeV protons in recurrent proton streams

    NASA Technical Reports Server (NTRS)

    Mewaldt, R. A.; Stone, E. C.; Vogt, R. E.

    1978-01-01

    The paper presents anisotropy measurements of 1.3-2.3 MeV protons in the interplanetary space during recurrent events for which the radial intensity variation is measured within the radial range from about 0.3 to about 4 AU for the period from June, 1973 through April, 1976. The simultaneous measurements of the diffusive anisotropy and the radial gradient are used to make a direct estimate of the interplanetary radial diffusion coefficient, which is independent of any particular solution of the propagation equation. IMP 7 and 8 is required to be sunward of the earth and hence outside of the magnetosphere; if both spacecraft are sunward, measurements from the one farthest from the magnetosphere are used. The resulting values for the radial diffusivity coefficient near 1 AU lie in the range (3 to 9) x 10 to the 20th sq cm/sec, corresponding to scattering mean free paths between 0.03 and 0.1 AU with a mean of 0.06 AU.

  13. Effect of 50 MeV Li 3+ ion irradiation on electrical characteristics of high speed NPN power transistor

    NASA Astrophysics Data System (ADS)

    Dinesh, C. M.; Ramani; Radhakrishna, M. C.; Dutt, R. N.; Khan, S. A.; Kanjilal, D.

    2008-04-01

    Silicon NPN overlay RF power high speed commercial bipolar junction transistors (BJTs) find applications in military, space and communication equipments. Here we report the effect of 50 MeV Li3+ ion irradiation in the fluence range 1 × 1011-1.8 × 1012 ions cm-2 on NPN power transistor. The range (R), electronic energy loss (Se), nuclear energy loss (Sn), total ionizing dose (TID) and total displacement damage (Dd) in the silicon target are calculated from TRIM Monte Carlo Code. Output resistance is 3.568 × 104 Ω for unirradiated device and it increases to 6 × 107 Ω as the fluence is increased from 1 × 1011 to 1.8 × 1012 ions cm-2. The capacitance of the emitter-base junction of the transistor decreases and dielectric loss of the emitter-base junction increases with increase in ion fluence. The built in voltage of the unirradiated sample is 0.5 V and it shifts to 0.4 V after irradiation at fluence of 1.8 × 1012 ions cm-2 and the corresponding doping density reduced to 5.758 × 1016 cm-3. The charge carrier removal rate varies linearly with the increase in ion fluence.

  14. Radiation effects on silicon bipolar transistors caused by 3-10 MeV protons and 20-60 MeV bromine ions

    NASA Astrophysics Data System (ADS)

    Li, Xingji; Geng, Hongbin; Lan, Mujie; Liu, Chaoming; Yang, Dezhuang; He, Shiyu

    2010-03-01

    The current gain degradation in silicon NPN bipolar junction transistors (BJTs) was examined under irradiation with 3-10 MeV protons and 20-60 MeV bromine (Br) ions with various dose levels. To characterize the radiation damage of the NPN BJTs, the ionizing dose D i and displacement dose D d as a function of chip depth in the NPN BJTs were calculated for both the protons and Br ions with different energies. Based on the irradiation testing and calculated results, it is shown that the current gain degradation of NPN BJTs is sensitive to the ratio of D d/( D d+ D i) in the sensitive region given by protons and Br ions. The irradiation particles (protons and Br ions), which give larger D d/( D d+ D i) at a given total dose, would generate more severe damage to the NPN BJTs. The reciprocal of the gain variation as a function of the displacement dose was compared, showing that the Messenger-Spratt equation becomes relevant to describe the experimental data, when the ratio of the D d/( D d+ D i) are larger and the displacement dose are higher than a certain value.

  15. Light beam range finder

    DOEpatents

    McEwan, T.E.

    1998-06-16

    A ``laser tape measure`` for measuring distance is disclosed which includes a transmitter such as a laser diode which transmits a sequence of electromagnetic pulses in response to a transmit timing signal. A receiver samples reflections from objects within the field of the sequence of visible electromagnetic pulses with controlled timing, in response to a receive timing signal. The receiver generates a sample signal in response to the samples which indicates distance to the object causing the reflections. The timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The receive timing signal causes the receiver to sample the reflection such that the time between transmission of pulses in the sequence in sampling by the receiver sweeps over a range of delays. The transmit timing signal causes the transmitter to transmit the sequence of electromagnetic pulses at a pulse repetition rate, and the received timing signal sweeps over the range of delays in a sweep cycle such that reflections are sampled at the pulse repetition rate and with different delays in the range of delays, such that the sample signal represents received reflections in equivalent time. The receiver according to one aspect of the invention includes an avalanche photodiode and a sampling gate coupled to the photodiode which is responsive to the received timing signal. The transmitter includes a laser diode which supplies a sequence of visible electromagnetic pulses. A bright spot projected on to the target clearly indicates the point that is being measured, and the user can read the range to that point with precision of better than 0.1%. 7 figs.

  16. Light beam range finder

    DOEpatents

    McEwan, Thomas E.

    1998-01-01

    A "laser tape measure" for measuring distance which includes a transmitter such as a laser diode which transmits a sequence of electromagnetic pulses in response to a transmit timing signal. A receiver samples reflections from objects within the field of the sequence of visible electromagnetic pulses with controlled timing, in response to a receive timing signal. The receiver generates a sample signal in response to the samples which indicates distance to the object causing the reflections. The timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The receive timing signal causes the receiver to sample the reflection such that the time between transmission of pulses in the sequence in sampling by the receiver sweeps over a range of delays. The transmit timing signal causes the transmitter to transmit the sequence of electromagnetic pulses at a pulse repetition rate, and the received timing signal sweeps over the range of delays in a sweep cycle such that reflections are sampled at the pulse repetition rate and with different delays in the range of delays, such that the sample signal represents received reflections in equivalent time. The receiver according to one aspect of the invention includes an avalanche photodiode and a sampling gate coupled to the photodiode which is responsive to the received timing signal. The transmitter includes a laser diode which supplies a sequence of visible electromagnetic pulses. A bright spot projected on to the target clearly indicates the point that is being measured, and the user can read the range to that point with precision of better than 0.1%.

  17. Refractive index profiles in YCa 4O(BO 3) 3 and Nd:YCa 4O(BO 3) 3 waveguides created by MeV He ions

    NASA Astrophysics Data System (ADS)

    Wang, Ke-Ming; Hu, Hui; Chen, Feng; Lu, Fei; Shi, Bo-Rong; Shen, Ding-Yu; Liu, Yao-Gang; Wang, Ji-Yang; Lu, Qing-Ming

    2002-05-01

    YCa 4O(BO 3) 3 (YCOB) is one of the rare-earth calcium oxyborate family of crystals. The crystal has good potential to be used for self-frequency doubling due to its excellent combination of nonlinear and laser properties. We have used MeV He + ions to make waveguides in YCOB and Nd:YCOB (NdYCOB) crystals. The ion implantation was carried out with 2.8 MeV He + ions at room temperature. The fluences have varied from 1.5×10 16 to 5.5×10 16 ions/cm 2. The model 2010 prism coupler was used to measure the modes in YCOB and NdYCOB waveguides formed by MeV He + ion implantation. The refractive index profiles are fitted based on the reflectivity calculation method. We have used TRIM'98 simulation to get the range and damage profiles by MeV He + ions in YCOB. Especially the refractive index change as a function of fluence is discussed.

  18. Study on geomagnetic storms driving motion of 0.1-2 MeV radiation belt electrons

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenxia; Li, Xinqiao

    2016-08-01

    Using more than five years' worth of data observed by the Instrument for the Detection of Particles (IDP) spectrometer onboard the Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions (DEMETER) satellite, we studied the motion characteristics of energetic electrons in different regions, i.e., the inner radiation belt, the outer radiation belt, and the slot region in geomagnetic storms. We investigated the flux change of 0.1-2.4 MeV electrons and the energy change of 0.1-1.0 MeV electrons in these different regions. By cross correlation analysis, we came to the following conclusions. First, when Dst < -50, the correlation coefficient (c.c.) of the electron flux and Dst index ranges from -0.63 to -0.86, and the enhancement of the electron flux generally occurs during the storm's main and recovery phases. Second, the storms greatly influence the lower energy region of the electron energy spectrum in the inner radiation belt, while the enhancement in the higher energy region is more significant in the outer radiation belt and the slot region. Third, the effects of geomagnetic storms on electrons are not distinguished significantly between in the day and night, and independent of the timing of the events. For storms with -50 < Dst < -30, there is a negative correlation of -0.51 to -0.57 between the Dst index and the electron flux in the outer radiation belt. Our analysis suggests that strong storms cause energetic electron ejections across a wide range, and the ejection level is affected by the storm intensity. Furthermore, the electron energy region influenced by the strong geomagnetic storms is opposite in the inner and outer radiation belts. The proportion of electrons accelerated to relativistic energies is greater in the outer radiation and slot regions, while the ejection energetic electrons are more concentrated in the low energy region of the inner radiation belt. This phenomenon reflects the different electron injection mechanisms and

  19. Steady-state operation and high energy particle production of MeV energy in the Large Helical Device

    NASA Astrophysics Data System (ADS)

    Mutoh, T.; Kumazawa, R.; Seki, T.; Saito, K.; Kasahara, H.; Nakamura, Y.; Masuzaki, S.; Kubo, S.; Takeiri, Y.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Watanabe, T.; Ogawa, H.; Miyazawa, J.; Shoji, M.; Ashikawa, N.; Nishimura, K.; Osakabe, M.; Tsumori, K.; Ikeda, K.; Nagaoka, K.; Oka, Y.; Chikaraishi, H.; Funaba, H.; Morita, S.; Goto, M.; Inagaki, S.; Narihara, K.; Tokuzawa, T.; Sakamoto, R.; Morisaki, T.; Peterson, B. J.; Tanaka, K.; Nakanishi, H.; Nishiura, M.; Ozaki, T.; Shimpo, F.; Nomura, G.; Takahashi, C.; Yokota, M.; Zhao, Y. P.; Kwak, J. G.; Murakami, S.; Okada, H.; Yamada, H.; Kawahata, K.; Ohyabu, N.; Kaneko, O.; Ida, K.; Nagayama, Y.; Watanabe, K. Y.; Noda, N.; Komori, A.; Sudo, S.; Motojima, O.

    2007-09-01

    Achieving steady-state plasma operation at high plasma temperatures is one of the important goals of worldwide magnetic fusion research. High temperatures of approximately 1-2 keV, and steady-state plasma sustainment operations have been reported. Recently the steady-state operation regime was greatly extended in the Large Helical Device (LHD). A high-temperature plasma was created and maintained for 54 min with 1.6 GJ in the 2005FY experimental programme. The three-dimensional heat-deposition profile of the LHD helical divertor was modified, and during long-pulse discharges it effectively dispersed the heat load using a magnetic axis swing technique developed at the LHD. A sweep of only 3 cm in the major radius of the magnetic axis position (less than 1% of the major radius of the LHD) was enough to disperse the divertor heat load. The steady-state plasma was heated and sustained mainly by hydrogen minority ion heating using ion cyclotron range of frequencies and partially by electron cyclotron of fundamental resonance frequency. By accumulating the small flux of charge-exchanged neutral particles during the long-pulse operation, a high energy ion tail which extended up to 1.6 MeV was observed. This is the first experimental evidence of high energetic ion confinement of MeV range in helical devices. The long-pulse operations lasted until a sudden increase in radiation loss occurred, presumably because of metal wall flakes dropping into the plasma. The sustained line-averaged electron density and temperature were approximately 0.8 × 1019 m-3 and 2 keV, respectively, at a 1.3 GJ discharge (#53776) and 0.4 × 1019 m-3 and 1 keV at a 1.6 GJ discharge (#66053). The average input power was 680 kW and 490 kW, and the plasma duration was 32 min and 54 min, respectively. These successful long operations show that the heliotron configuration has a high potential as a steady-state fusion reactor.

  20. A new 5 MeV-300 kW dynamitron for radiation processing

    NASA Astrophysics Data System (ADS)

    Galloway, R. A.; Lisanti, T. F.; Cleland, M. R.

    2004-09-01

    The high beam power required to deliver reasonably effective levels of X-rays for processing food and medical products has driven the development of a new high-power Dynamitron ® system. For many years, RDI accelerators have been providing up to 200 kW of DC electron beam power at energies up to 5.0 MeV. This new system, designed to operate at 300 kW of beam power at 5.0 MeV, is also capable of producing up to 75 mA of beam current when operating at lower voltages. Achieving this high power level and maintaining the high reliability that Dynamitrons are known for has required new designs offering lower power losses yielding higher efficiency and reducing stress in critical components. Improvements in beam control and optics add to the stability and reliability of the system providing a basis for a highly reliable high-power system.

  1. Plasma production for the 50 MeV plasma lens experiment at LBL

    SciTech Connect

    Leemans, W.; van der Geer, B.; de Loos, M.; Conde, M.; Govil, R.; Chattopadhyay, S.

    1994-06-01

    The Center for Beam Physics at LBL has constructed a Beam Test Facility (BTF) housing a 50 MeV electron beam transport line, which uses the linac injector from the Advanced Light Source, and a terawatt Ti:Al{sub 2}O{sub 3} laser system. The linac operates at 50 MeV and generates 15 ps long electron bunches containing a charge of up to 2 nC. The measured unnormalized beam emittance is 0.33 mm-mrad. These parameters allow for a comprehensive study of focusing of relativistic electron beams with plasma columns, in both the overdense and underdense regime (adiabatic and tapered lenses). A study of adiabatic and/or tapered lenses requires careful control of plasma density and scale lengths of the plasma. We present experimental results on the production of plasmas through resonant two-photon ionization, with parameters relevant to an upcoming plasma lens experiment.

  2. Probing MeV dark matter at low-energy e+e- colliders.

    PubMed

    Borodatchenkova, Natalia; Choudhury, Debajyoti; Drees, Manuel

    2006-04-14

    It has been suggested that the pair annihilation of dark matter particles chi with mass between 0.5 and 20 MeV into e+e- pairs could be responsible for the excess flux (detected by the INTEGRAL satellite) of 511 keV photons coming from the central region of our Galaxy. The simplest way to achieve the required cross section while respecting existing constraints is to introduce a new vector boson U with mass M(U) below a few hundred MeV. We point out that over most of the allowed parameter space, the process e+e--->U(gamma), followed by the decay of U into either an e+e- pair or an invisible (nu(-)nu or chi(-)chi) channel, should lead to signals detectable by current B-factory experiments. A smaller, but still substantial, region of parameter space can also be probed at the Phi factory DAPhiNE.

  3. Energy loss and straggling of MeV ions through biological samples

    SciTech Connect

    Ma Lei; Wang Yugang; Xue Jianming; Chen Qizhong; Zhang Weiming; Zhang Yanwen

    2007-10-15

    Energy loss and energy straggling of energetic ions through natural dehydrated biological samples were investigated using transmission technique. Biological samples (onion membrane, egg coat, and tomato coat) with different mass thickness were studied, together with Mylar for comparison. The energy loss and energy straggling of MeV H and He ions after penetrating the biological and Mylar samples were measured. The experimental results show that the average energy losses of MeV ions through the biological samples are consistent with SRIM predictions; however, large deviation in energy straggling is observed between the measured results and the SRIM predictions. Taking into account inhomogeneity in mass density and structure of the biological sample, an energy straggling formula is suggested, and the experimental energy straggling values are well predicted by the proposed formula.

  4. Energy loss and straggling of MeV ions through biological samples

    SciTech Connect

    Ma, Lie; Wang, Yugang; Xue, Jianming; Chen, Qizhong; Zhang, Weiming; Zhang, Yanwen

    2007-10-15

    Energy loss and energy straggling of energetic ions through natural dehydrated biological samples were investigated using transmission technique. Biological samples (onion membrane, egg coat and tomato coat) with different mass thickness were studied, together with mylar for comparison, in this work. The energy loss and energy straggling of MeV H and He ions after penetrating from the biological and mylar samples were measured. The experimental results show that the average energy losses of MeV ions through the biological samples are consistent with SRIM predictions, however, large deviation in energy straggling is observed between the measured result and the SRIM predictions. Taking into account inhomogeneity in mass density and structure of the biological sample, an energy straggling formula is suggested, and the experimental energy straggling values are well predicated by the proposed formula.

  5. MeV ion beam interaction with polymer films containing cross-linking agents

    SciTech Connect

    Evelyn, A. L.

    1999-06-10

    Polymer films containing cross linking enhancers were irradiated with MeV alpha particles to determine the effects of MeV ion beam interaction on these materials. The contributed effects from the electronic and nuclear stopping powers were separated by irradiating stacked thin films of polyvinyl chloride (PVC), polystyrene (PS) and polyethersulfone (PES). This layered system allowed most of the effects of the electronic energy deposited to be experienced by the first layers and the last layers to receive most of the effects of the nuclear stopping power. RGA, Raman microprobe analysis, RBS and FTIR measured changes in the chemical structures of the irradiated films. The characterization resolved the effects of the stopping powers on the PVC, PS and PES and the results were compared with those from previously studied polymers that did not contain any cross linking agents.

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

    SciTech Connect

    Evelyn, A.L.; Ila, D.; Zimmerman, R.L.; Bhat, K.; Poker, D.B.; Hensley, D.K.

    1997-02-01

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

  7. A new proton fluence model for E greater than 10 MeV

    NASA Technical Reports Server (NTRS)

    Feynman, Joan; Armstrong, T. P.; Dao-Gibner, L.; Silverman, S.

    1988-01-01

    Researchers describe a new engineering model for the fluence of protons with energies greater than 10 MeV. The data set used is a combination of observations made primarily from the Earth's surface between 1956 and 1963 and observations made from spacecraft in the vicinity of Earth between 1963 and 1985. With this data set we find that the distinction between ordinary proton events and anomalously large proton events made in earlier work disappears. The greater than 10 MeV fluences at 1 AU calculated with the new model are about twice those expected on the basis of models now in use. In contrast to earlier models, results do not depend critically on the fluence from any one event.

  8. Transverse Beam Emittance Measurements of a 16 MeV Linac at the Idaho Accelerator Center

    SciTech Connect

    S. Setiniyaz, T.A. Forest, K. Chouffani, Y. Kim, A. Freyberger

    2012-07-01

    A beam emittance measurement of the 16 MeV S-band High Repetition Rate Linac (HRRL) was performed at Idaho State University's Idaho Accelerator Center (IAC). The HRRL linac structure was upgraded beyond the capabilities of a typical medical linac so it can achieve a repetition rate of 1 kHz. Measurements of the HRRL transverse beam emittance are underway that will be used to optimize the production of positrons using HRRL's intense electron beam on a tungsten converter. In this paper, we describe a beam imaging system using on an OTR screen and a digital CCD camera, a MATLAB tool to extract beamsize and emittance, detailed measurement procedures, and the measured transverse emittances for an arbitrary beam energy of 15 MeV.

  9. Modification & alignment of beam line of 10 MeV RF electron beam accelerator

    NASA Astrophysics Data System (ADS)

    Barnwal, R.; Ghodke, S. R.; Bhattacharjee, D.; Kumar, M.; Jayaprakash, D.; Chindarkar, A. R.; Mishra, R. L.; Dolas, S.; Kulkarni, S. Y.; Kumar, M.; P, Dixit K.; S, Acharya; Barje, S. R.; Lawangare, N. K.; C, Saroj P.; Nimje, V. T.; Chandan, S.; Tillu, A. R.; V, Sharma; Chavan, R. B.; V, Yadav; P, Roychowdhury; Mittal, K. C.; Chakravarthy, D. P.; Ray, A. K.

    2008-05-01

    A 10 MeV, 10 kW RF industrial Electron linac designed and developed at BARC is installed at the Electron Beam Center Kharghar, Navi Mumbai. The entire RF accelerator assembly consists of Electron gun, RF source, RF linac structure, Beam diagnostic chamber, Drift tube, Scanning magnet, Beam sensing aperture, Scan horn, and is spread over two floors at EBC. The paper discusses in detail about the alignment procedure adopted for the equipments of 10 MeV RF beamline. The complete electron beamline will be maintained under ultra high vacuum of the order of 10-7 torr. The paper discusses about the present problem of alignment, measurement technique of alignment, reason for misalignment, possible ways to solve the problem, equipment used for alignment, supports & arrestors, verification of alignment under vacuum

  10. Analysis of the pp analyzing-power data at 50.04 Mev

    NASA Astrophysics Data System (ADS)

    Stoks, V. G. J.; de Swart, J. J.

    1990-07-01

    The recent, very accurate proton-proton analyzing-power measurements by the Zürich group at tlab = 50.04 MeV are analyzed. We show that in order to arrive at a proper description of these data, the magnetic-moment interaction has to be included in all partial waves. It is also shown that some of the approximations made in the literature, when trying to incorporate this magnetic-moment interaction, are inadequate. From these beautiful data one can now determine quite accurately the phase shifts at 50 MeV. We compare our results with the phase shifts found in other phase-shift analyses. Some of our phase shifts differ by 6-9 standard deviations from these analyses. Finally, we compare the predictions of some well-known nucleon-nucleon potential models with these high-precision data.

  11. A three-dimensional study of 30- to 300-MeV atmospheric gamma rays

    NASA Technical Reports Server (NTRS)

    Thompson, D. J.

    1974-01-01

    A three-dimensional study of atmospheric gamma rays with energy greater than 30 MeV has been carried out. A knowledge of these atmospheric secondaries has significant applications to the study of cosmic gamma rays. For detectors carried on balloons, atmospherically produced gamma rays are the major source of background. For satellite detectors, atmospheric secondaries provide a calibration source. Experimental results were obtained from four balloon flights from Palestine, Texas, with a 15 cm by 15 cm digitized wire grid spark chamber. The energy spectrum for downward-moving gamma rays steepens with increasing atmospheric depth. Near the top of the atmosphere, the spectrum steepens with increasing zenith angle. A new model of atmospheric secondary production has calculated the depth, the energy, and the zenith angle dependence of gamma rays above 30 MeV, using a comprehensive three-dimensional Monte Carlo model of the nucleon-meson-electromagnetic cascade.

  12. The New Sorgentina Fusion Source-NSFS: 14 MeV neutrons for fusion and beyond

    NASA Astrophysics Data System (ADS)

    Pietropaolo, A.; Console Camprini, P.; Agostini, P.; Amendola, R.; Angelone, M.; Bernardi, D.; Bruni, F.; Capogni, M.; Colognesi, D.; Faccini, R.; Filabozzi, A.; Flammini, D.; Fiori, F.; Frisoni, M.; Grazzi, F.; Pillon, M.; Pizzuto, A.; Quintieri, L.; Sacchetti, F.; Valente, P.

    2016-09-01

    The importance of the design for the realization of an intense 14 MeV neutron facility devoted to test and validate materials suitable for harsh neutron environments, such as a fusion reactor, is well established. The “New Sorgentina” Fusion Source (NSFS) is a project that proposes an intense D-T 14 MeV neutron source achievable with T and D ion beams impinging on 2 m radius rotating targets. NSFS may produce about 1015 n/s at the target and has to be intended as an European facility that maybe realized in a few years, once provided a preliminary technological program devoted to the operation of the ion source in continuous mode, target heat loading/removal, target and tritium handling, inventor as well as site licensing. In this contribution, the main characteristics of NSFS project will be presented and its possible use as a multipurpose facility outlined.

  13. STATUS OF NEW 2.5 MEV TEST FACILITY AT SNS

    SciTech Connect

    Aleksandrov, Alexander V; Champion, Mark; Crofford, Mark T; Kang, Yoon W; Menshov, Alexander A; Roseberry, Jr., R Tom; Stockli, Martin P; Webster, Anthony W; Welton, Robert F; Zhukov, Alexander P

    2014-01-01

    A new 2.5MeV beam test facility is being built at SNS. It consists of a 65 keV H- ion source, a 2.5MeV RFQ, a beam line with various beam diagnostics and a 6 kW beam dump. The facility is capable of producing one-ms-long pulses at 60Hz repetition rate with up to 50mA peak current. The commissioning with reduced average beam power is planned for fall 2014 to verify operation of all systems. The full power operation is scheduled to begin in 2015. The status of the facility will be presented as well as a discussion of the future R&D program.

  14. Gas cooking range

    SciTech Connect

    Narang, R.K.; Narang, K.

    1984-02-14

    An energy-efficient gas cooking range features an oven section with improved heat circulation and air preheat, a compact oven/broiler burner, a smoke-free drip pan, an efficient piloted ignition, flame-containing rangetop burner rings, and a small, portable oven that can be supported on the burner rings. Panels spaced away from the oven walls and circulation fans provide very effective air flow within the oven. A gas shutoff valve automatically controls the discharge of heated gases from the oven so that they are discharged only when combustion is occurring.

  15. Light response of YAP:Ce and LaBr3:Ce scintillators to 4-30 MeV protons for applications to Telescope Proton Recoil neutron spectrometers

    NASA Astrophysics Data System (ADS)

    Cazzaniga, C.; Cremona, A.; Nocente, M.; Rebai, M.; Rigamonti, D.; Tardocchi, M.; Croci, G.; Ericsson, G.; Fazzi, A.; Hjalmarsson, A.; Mazzocco, M.; Strano, E.; Gorini, G.

    2016-06-01

    The light response of two thin inorganic scintillators based on YAP:Ce and LaBr3:Ce crystals has been measured with protons in the 4-8 MeV energy range at the Uppsala tandem accelerator and in the 8-26 MeV energy range at the Legnaro tandem accelerator. The crystals have been calibrated in situ with 137Cs and 60Co γ-ray sources. The relative light yields of protons with respect to gammas have been measured and are here reported to be (96±2)% and (80±2)% for YAP:Ce and LaBr3:Ce, respectively. The results open up to the development of a Telescope Proton Recoil spectrometer based on either of the two crystals as alternative to a silicon based spectrometer for applications to high neutron fluxes.

  16. Scattering of {sup 8}He on {sup 208}Pb at 22 MeV

    SciTech Connect

    Marquinez-Duran, G.; Sanchez-Benitez, A. M.; Martel, I.; Berjillos, R.; Duenas, J. A.; Parkar, V. V.; Acosta, L.; Rusek, K.; Alvarez, M. A. G.; Gomez-Camacho, J.; Borge, M. J. G.; Cruz, C.; Cubero, M.; Pesudo, V.; Tengblad, O.; Chbihi, A.; Fernandez-Garcia, J. P.; Moro, A. M.; Fernandez-Martinez, B.; Labrador, J. A.; and others

    2013-06-10

    The skin nucleus {sup 8}He is investigated by measuring the angular distribution of the elasticly scattered {sup 8}He and the {sup 6,4}He fragments produced in the collision with a {sup 208}Pb target at 22 MeV, just above the Coulomb barrier. The experiment was carried out at SPIRAL/GANIL in 2010. Here we present preliminary results for the elastic scattering.

  17. Comments on (n, charged particle) reactions at E/sub n/ = 14 MeV

    SciTech Connect

    Haight, R.C.

    1984-01-01

    The study of charged particles produced by bombarding materials with 14 MeV neutrons is important for the development of fusion reactors and for biomedical applications as well as for the basic understanding of nuclear reactions. Several experimental techniques for investigating these reactions are discussed here. The interpretation of the data requires the consideration of several possible reaction mechanisms including equilibrium and preequilibrium particle emission and, for light nuclei, sequential particle emission, final state interactions, and the effect of resonances. 17 references.

  18. Voltage holding study of 1 MeV accelerator for ITER neutral beam injector

    SciTech Connect

    Taniguchi, M.; Kashiwagi, M.; Umeda, N.; Dairaku, M.; Takemoto, J.; Tobari, H.; Tsuchida, K.; Yamanaka, H.; Watanabe, K.; Kojima, A.; Hanada, M.; Sakamoto, K.; Inoue, T.

    2012-02-15

    Voltage holding test on MeV accelerator indicated that sustainable voltage was a half of that of ideal quasi-Rogowski electrode. It was suggested that the emission of the clumps is enhanced by a local electric field concentration, which leads to discharge initiation at lower voltage. To reduce the electric field concentration in the MeV accelerator, gaps between the grid supports were expanded and curvature radii at the support corners were increased. After the modifications, the accelerator succeeded in sustaining -1 MV in vacuum without beam acceleration. However, the beam energy was still limited at a level of 900 keV with a beam current density of 150 A/m{sup 2} (346 mA) where the 3 x 5 apertures were used. Measurement of the beam profile revealed that deflection of the H{sup -} ions was large and a part of the H{sup -} ions was intercepted at the acceleration grid. This causes high heat load on the grids and the breakdowns during beam acceleration. To suppress the direct interception, new grid system was designed with proper aperture displacement based on a 3D beam trajectory analysis. As the result, the beam deflection was compensated and the voltage holding during the beam acceleration was improved. Beam parameter of the MeV accelerator was increased to 980 keV, 185 A/m{sup 2} (427 mA), which is close to the requirement of ITER accelerator (1 MeV, 200 A/m{sup 2}).

  19. Nuclear multifragmentation by 700–1500 MeV photons: New data of GRAAL experiment

    SciTech Connect

    Nedorezov, V. G. Lapik, A. M.; Collaboration: GRAAL Collaboration

    2015-12-15

    The cross sections of carbon nucleus photodisintegration into protons and neutrons with high multiplicity for photon energies from 700 to 1500 MeV were measured. The experiment was performed at the tagged photon beam of the GRAAL setup using the wide-aperture detector LAGRANγE. It was shown that multifragmentation up to complete disintegration into separate nucleons is initiated by elementary reactions of meson photoproduction with a subsequent intranuclear cascade.

  20. Accelerator driven system based on plutonium subcritical reactor and 660 MeV phasotron

    NASA Astrophysics Data System (ADS)

    Arkhipov, V. A.; Barashenkov, V. S.; Buttsev, V. S.; Chultem, D.; Dudarev, S. Yu.; Furman, V. I.; Gudowski, W.; Janczyszyn, J.; Maltsev, A. A.; Onischenko, L. M.; Pogodajev, G. N.; Polanski, A.; Popov, Yu. P.; Puzynin, I. V.; Sissakian, A. N.; Taczanowski, S.

    1999-11-01

    The proposal presents a PLUTONIUM BASED ENERGY AMPLIFIER TESTING CONCEPT which employs a plutonium subcritical assembly and a 660 MeV proton accelerator, operating in the the JINR (Dubna, Russia). To make the present conceptual design of the Plutonium Energy Amplifier we have chosen a nominal unit capacity of 20 kW (thermal). This corresponds to the multiplication coefficient keff between 0.94 and 0.95 and the energetic gain about 20.

  1. Biomedical user facility at the 400-MeV Linac at Fermilab

    SciTech Connect

    Chu, W.T.

    1993-12-01

    In this paper, general requirements are discussed on a biomedical user facility at the Fermilab`s 400-MeV Linac, which meets the needs of biology and biophysics experiments, and a conceptual design and typical operations requirements of the facility is presented. It is assumed that no human patient treatment will take place in this facility. If human patients were treated, much greater attention would have to be paid to safeguarding the patients.

  2. Impurity/defect interactions during MeV Si{sup +} ion implantation annealing

    SciTech Connect

    Agarwal, A.; Koveshnikov, S.; Christensen, K.

    1995-08-01

    Ion implantation of dopant atoms at MeV energies is currently being explored in several integrated circuit device manufacturing processes. MeV implantation offers immediate advantages such as vertical well modulation, latch-up protection, device structure isolation, and reduced temperature processing. Simultaneously, it presents an opportunity to achieve {open_quotes}proximity{close_quotes} gettering of impurities from the active device region by placing high impurity solubility and/or secondary defect gettering sites within microns of the surface. If the MeV implanted species is a dopant ion, all three gettering mechanisms, i.e, segregation, relaxation and injection, can be involved in the gettering process, complicating the analysis and optimization of the process. However, investigation of gettering using non-dopant Si{sup +} ion damage allows the relaxation component of the gettering process to be isolated and examined separately. In general, gettering is verified by a reduction in impurity concentration in the region of interest, usually the device region, and/or a build-up of concentration/precipitation in a non-device sink region. An alternate and more meaningful approach is to use simple devices as materials characterization probes via changes in the electrical activity of the gettering sites. Device space charge probes also allow the evolution of the defect sites upon contamination to be tracked. We report here results of the electrical, structural, and chemical characterization of MeV implanted Si{sup +} damage using Deep Level Transient Spectroscopy (DLTS), Transmission Electron Microscopy (TEM), and Secondary Ion Mass Spectroscopy (SIMS). The damage has been characterized both as a function of annealing from 600 to 1100{degrees}C for 1 hr, and after contamination with Fe followed by low temperature gettering annealing.

  3. Irradiation Effects of 22 and 240 MeV Protons on Several Transistors and Solar Cells

    NASA Technical Reports Server (NTRS)

    Hulten, W. C.; Honaker, W. C.; Patterson, John L.

    1961-01-01

    The work covered in this report has been directed toward the investigation of the irradiation effects of 22 and 240 MeV protons on several transistors, solar cells, resistors, and condensers to be used in the space radiation environment. The experimental data indicated definite detrimental effects on transistors and solar cells but no apparent effects on the types of resistors and condensers tested. The detrimental effects are of two distinct types: transient and permanent.

  4. Direct experimental reconstruction of the pp elastic scattering matrix at 579 MeV

    SciTech Connect

    Aprile, E.; Eisenegger, C.; Hausammann, R.; Heer, E.; Hess, R.; Lechanoine-Leluc, C.; Leo, W.R.; Morenzoni, S.; Onel, Y.; Rapin, D.; Mango, S.

    1981-04-20

    We have made, for the first time, a direct reconstruction of the pp elastic scattering matrix at 579 MeV from a series of experiments performed with a polarized beam line. Fifteen observables consisting of the polarization, two-spin correlation and transfer parameters, and three-spin parameters were measured at seven angles between 66/sup 0/ and 90/sup 0/ center of mass. The experimental results and reconstructed amplitudes are presented and compared to a phase-shift analysis.

  5. Western Aeronautical Test Range

    NASA Technical Reports Server (NTRS)

    Sakahara, Robert D.

    2008-01-01

    NASA's Western Aeronautical Test Range (WATR) is a network of facilities used to support aeronautical research, science missions, exploration system concepts, and space operations. The WATR resides at NASA's Dryden Flight Research Center located at Edwards Air Force Base, California. The WATR is a part of NASA's Corporate Management of Aeronautical Facilities and funded by the Strategic Capability Asset Program (SCAP). It is managed by the Aeronautics Test Program (ATP) of the Aeronautics Research Mission Directorate (ARMD) to provide the right facility at the right time. NASA is a tenant on Edwards Air Force Base and has an agreement with the Air Force Flight Test Center to use the land and airspace controlled by the Department of Defense (DoD). The topics include: 1) The WATR supports a variety of vehicles; 2) Dryden shares airspace with the AFFTC; 3) Restricted airspace, corridors, and special use areas are available for experimental aircraft; 4) WATR Products and Services; 5) WATR Support Configuration; 6) Telemetry Tracking; 7) Time Space Positioning; 8) Video; 9) Voice Communication; 10) Mobile Operations Facilities; 11) Data Processing; 12) Mission Control Center; 13) Real-Time Data Analysis; and 14) Range Safety.

  6. Monocular visual ranging

    NASA Astrophysics Data System (ADS)

    Witus, Gary; Hunt, Shawn

    2008-04-01

    The vision system of a mobile robot for checkpoint and perimeter security inspection performs multiple functions: providing surveillance video, providing high resolution still images, and providing video for semi-autonomous visual navigation. Mid-priced commercial digital cameras support the primary inspection functions. Semi-autonomous visual navigation is a tertiary function whose purpose is to reduce the burden of teleoperation and free the security personnel for their primary functions. Approaches to robot visual navigation require some form of depth perception for speed control to prevent the robot from colliding with objects. In this paper present the initial results of an exploration of the capabilities and limitations of using a single monocular commercial digital camera for depth perception. Our approach combines complementary methods in alternating stationary and moving behaviors. When the platform is stationary, it computes a range image from differential blur in the image stack collected at multiple focus settings. When the robot is moving, it extracts an estimate of range from the camera auto-focus function, and combines this with an estimate derived from angular expansion of a constellation of visual tracking points.

  7. Range Process Simulation Tool

    NASA Technical Reports Server (NTRS)

    Phillips, Dave; Haas, William; Barth, Tim; Benjamin, Perakath; Graul, Michael; Bagatourova, Olga

    2005-01-01

    Range Process Simulation Tool (RPST) is a computer program that assists managers in rapidly predicting and quantitatively assessing the operational effects of proposed technological additions to, and/or upgrades of, complex facilities and engineering systems such as the Eastern Test Range. Originally designed for application to space transportation systems, RPST is also suitable for assessing effects of proposed changes in industrial facilities and large organizations. RPST follows a model-based approach that includes finite-capacity schedule analysis and discrete-event process simulation. A component-based, scalable, open architecture makes RPST easily and rapidly tailorable for diverse applications. Specific RPST functions include: (1) definition of analysis objectives and performance metrics; (2) selection of process templates from a processtemplate library; (3) configuration of process models for detailed simulation and schedule analysis; (4) design of operations- analysis experiments; (5) schedule and simulation-based process analysis; and (6) optimization of performance by use of genetic algorithms and simulated annealing. The main benefits afforded by RPST are provision of information that can be used to reduce costs of operation and maintenance, and the capability for affordable, accurate, and reliable prediction and exploration of the consequences of many alternative proposed decisions.

  8. Linac-beam characterizations at 600 MeV using optical transition radiation diagnostics

    NASA Astrophysics Data System (ADS)

    Lumpkin, A. H.; Berg, W. J.; Yang, B. X.; White, M.

    1998-12-01

    Selected optical diagnostics stations were upgraded in anticipation of low-emittance, bright electron beams from a thermionic rf gun or a photoelectric rf gun on the Advanced Photon Source (APS) injector linac. The upgrades include the installation of optical transition radiation (OTR) screens, transport lines, and cameras for use in transverse beam size measurements and longitudinal profile measurements. Using beam from the standard thermionic gun, tests were done at 50 MeV and 400 to 650 MeV. Data were obtained on the limiting spatial (σ˜200 μm) and temporal resolutions (300 ms) of the Chromox (Al2O3:Cr) screen (250 μm thick) in comparison to the OTR screens. Both charge-ecoupled device (CCD) and charge-injection device (CID) video cameras were used, as well as a Hamamatsu C5680 synchroscan streak camera operating at a vertical deflection rate of 119.0 MHz (the 24th subharmonic of the S-band 2856 MHz frequency). Beam transverse sizes as small as σx=60 μm for a 600 MeV beam and micropulse bunch lengths of στ<3 ps have been recorded for macropulse-averaged behavior with charges of about 2 to 3 nC per macropulse. These techniques are applicable to linac-driven, fourth-generation light source R&D experiments, including the APS's SASE FEL experiment.

  9. μCF based 14 MeV intense neutron source

    NASA Astrophysics Data System (ADS)

    Anisimov, V. V.; Cavalleri, E.; Karmanov, F. I.; Konobeyev, A. Yu.; Latysheva, L. N.; Ponomarev, L. I.; Pshenichnov, I. A.; Slobodtchouk, V. I.; Vecchi, M.

    1999-06-01

    Results of a design study for an advanced scheme of a μCF based 14 MeV intense neutron source for test material irradiation including the liquid lithium primary target and a low temperature liquid deuterium-tritium (D-T) mixture as a secondary target are presented. According to this scheme negative pions are produced inside a 150-cm-long 0.75-cm-radius lithium target. Pions and muons resulting from the pion decay in flight are collected in the backward direction and stopped in the D-T mixture. The fusion chamber has the shape of a 10-cm-radius sphere surrounded by two 0.03-cm-thickness titanium shells. Assuming 100 fusions per muon in this scheme one can produce 14-MeV neutrons with a source strength up to 1017 n/s. A neutron flux of up to 1014 n/cm2/s can be achieved in a test volume of about 2.5 l and on the surface of about 350 cm2. The results of the thermophysical and thermomechanical analysis show that the technological limits are not exceeded. This source has the advantage of producing the original 14 MeV fusion spectrum without tails, isotropically into a 4π solid angle, contrary to the d-Li stripping neutron source.

  10. Measurement of Ay for the pd Breakup Reaction at 250 MeV

    SciTech Connect

    Maeda, Y.; Uesaka, T.; Kawabata, T.; Suda, K.; Sasamoto, Y.; Sakaguchi, S.; Sakai, H.; Yako, K.; Sasano, M.; Noji, S.; Hatanaka, K.; Tamii, A.; Shimizu, Y.; Takechi, M.; Tameshige, Y.; Matsubara, H.; Sagara, K.; Wakasa, T.; Dozono, M.; Ihara, E.

    2007-06-13

    From the recent studies, it has been found that the differential cross sections of the elastic Nd scattering at the energy below 150 MeV can be well reproduced by incorporating the 3NF in the Faddeev calculation based on modern nucleon-nucleon (NN) interactions. On the other hand, the differential cross sections of nd and pd at 250 MeV show large discrepancies between the data and the Faddeev calculations with 3NF. It indicates the presence of the missing features of the three nucleon system at this energy region. For the next step of the 3NF study, we measured the vector analyzing power Ay and the differential cross sections for the 2H(p, pp)n breakup reaction at 250 MeV. The experiment was carried out by detecting two protons in the final state with using the double-armed spectrometer Grand Raiden (GR) and Large Acceptance Spectrometer (LAS) at Research Center for Nuclear Physics (RCNP). These data provide important information on the 3NF effects and make a discrimination between 3NF models.

  11. Trends and applications for MeV electrostatic ion beam accelerators

    NASA Astrophysics Data System (ADS)

    Norton, G. A.; Stodola, S. E.

    2014-08-01

    The 1970s into the 1980s saw a major broadening of applications for electrostatic accelerators. Prior to this time, all accelerators were used primarily for nuclear structure research. In the 70s there was a significant move into production ion implantation with the necessary MeV ion beam analysis techniques such as RBS and ERD. Accelerators are still being built for these materials analysis techniques today. However, there is still a great ongoing expansion of applications for these machines. At the present time, the demand for electrostatic accelerators is near an all time high. The number of applications continues to grow. This paper will touch on some of the current applications which are as diverse as nuclear fission reactor developments and pharmacokinetics. In the field of nuclear engineering, MeV ion beams from electrostatic accelerators are being used in material damage studies and for iodine and actinide accelerator mass spectrometry (AMS). In the field of pharmacokinetics, electrostatic MeV accelerators are being used to detect extremely small amounts of above background 14C. This has significantly reduced the time required to reach first in human studies. These and other applications will be discussed.

  12. ({ital p},{ital d}) reaction on {sup 62}Ni at 65 MeV

    SciTech Connect

    Matoba, M.; Kurohmaru, K.; Iwamoto, O.; Nohtomi, A.; Uozumi, Y.; Sakae, T.; Koori, N.; Ohgaki, H.; Ijiri, H.; Maki, T.; Nakano, M.; Sen Gupta, H.M.

    1996-04-01

    The {sup 62}Ni({ital p},{ital d}){sup 61}Ni reaction has been studied with 65 MeV polarized protons. Angular distributions of the differential cross section and analyzing power have been measured for neutron hole states in {sup 61}Ni up to an excitation energy of 7 MeV. The data analysis with a standard distorted-wave Born approximation theory provides transferred angular momenta {ital l} and {ital j} and spectroscopic factors for several strongly excited states. The 1{ital f}{sub 7/2} hole state spreads largely in the excitation energy region of 2{endash}6 MeV, while the 1{ital f}{sub 5/2}, 2{ital p}{sub 3/2}, and 2{ital p}{sub 1/2} hole states into only 2{endash}4 levels. The strength function of the 1{ital f}{sub 7/2} hole state is analyzed with an asymmetrical Lorentzian function. The damping mechanism of the single hole states is discussed. {copyright} {ital 1996 The American Physical Society.}

  13. A 0. 5 to 3. 0 MeV monoenergetic positron beam

    SciTech Connect

    Huomo, H.; AsokaKumar, P.; Henderson, S.D.; Phlips, B.F.; Mayer, R.; McDonough, J.; Hacker, H.; McCorkle, S.; Schnitzenbaumer, P.; Greenberg, J.S.

    1988-01-01

    An adjustable, 0.5--3 MeV monoenergetic positron beam has been constructed at Brookhaven. Currently a /sup 22/Na source with a W(100) foil transmission moderator produces a 1.1 mm FWHN beam with an intensity of 3/times/10/sup 5/ e/sup +//sec at a target located downstream from the accelerator. The divergence of the beam is less than 0.1/degree/ at 2.2 MeV energy. A SOA gun with 2 lens transport system brings the beam to a focus at the entrance of an electrostatic 3 MeV Dynamitron accelerator. The post acceleration beam transport system comprises 3 focusing solenolds, 4 sets of steering magnets and a 90/degree/ double focusing bending magnet. The beam energy spread at the target is <1 keV FWHN deduced from the beam size. Below we describe the positron extraction optics and acceleration, the construction of the beamline and the beam diagnostic devices. The salient beam parameters are listed at the end of this paper. 2 refs., 3 figs., 1 tab.

  14. Simulation of electron behavior in PIG ion source for 9 MeV cyclotron

    NASA Astrophysics Data System (ADS)

    J. Mu, X.; Ghergherehchi, M.; H. Yeon, Y.; W. Kim, J.; S. Chai, J.

    2014-12-01

    In this paper, we focus on a PIG source for producing intense H-ions inside a 9 MeV cyclotron. The properties of the PIG ion source were simulated for a variety of electric field distributions and magnetic field strengths using a CST particle studio. After analyzing the secondary electron emission (SEE) as a function of both magnetic and electric field strengths, we found that for the modeled PIG geometry, a magnetic field strength of 0.2 T provided the best results in terms of the number of secondary electrons. Furthermore, at 0.2 T, the number of secondary electrons proved to be greatest regardless of the cathode potential. Also, the modified PIG ion source with quartz insulation tubes was tested in a KIRAMS-13 cyclotron by varying the gas flow rate and arc current, respectively. The capacity of the designed ion source was also demonstrated by producing plasma inside the constructed 9 MeV cyclotron. As a result, the ion source is verified as being capable of producing an intense H- beam and high ion beam current for the desired 9 MeV cyclotron. The simulation results provide experimental constraints for optimizing the strength of the plasma and final ion beam current at a target inside a cyclotron.

  15. CR-39 track detector calibration for H, He, and C ions from 0.1-0.5 MeV up to 5 MeV for laser-induced nuclear fusion product identification

    SciTech Connect

    Baccou, C. Yahia, V.; Labaune, C.; Depierreux, S.; Neuville, C.; Goyon, C.; Consoli, F.; De Angelis, R.; Ducret, J. E.; Boutoux, G.; Rafelski, J.

    2015-08-15

    Laser-accelerated ion beams can be used in many applications and, especially, to initiate nuclear reactions out of thermal equilibrium. We have experimentally studied aneutronic fusion reactions induced by protons accelerated by the Target Normal Sheath Acceleration mechanism, colliding with a boron target. Such experiments require a rigorous method to identify the reaction products (alpha particles) collected in detectors among a few other ion species such as protons or carbon ions, for example. CR-39 track detectors are widely used because they are mostly sensitive to ions and their efficiency is near 100%. We present a complete calibration of CR-39 track detector for protons, alpha particles, and carbon ions. We give measurements of their track diameters for energy ranging from hundreds of keV to a few MeV and for etching times between 1 and 8 h. We used these results to identify alpha particles in our experiments on proton-boron fusion reactions initiated by laser-accelerated protons. We show that their number clearly increases when the boron fuel is preformed in a plasma state.

  16. CR-39 track detector calibration for H, He, and C ions from 0.1-0.5 MeV up to 5 MeV for laser-induced nuclear fusion product identification.

    PubMed

    Baccou, C; Yahia, V; Depierreux, S; Neuville, C; Goyon, C; Consoli, F; De Angelis, R; Ducret, J E; Boutoux, G; Rafelski, J; Labaune, C

    2015-08-01

    Laser-accelerated ion beams can be used in many applications and, especially, to initiate nuclear reactions out of thermal equilibrium. We have experimentally studied aneutronic fusion reactions induced by protons accelerated by the Target Normal Sheath Acceleration mechanism, colliding with a boron target. Such experiments require a rigorous method to identify the reaction products (alpha particles) collected in detectors among a few other ion species such as protons or carbon ions, for example. CR-39 track detectors are widely used because they are mostly sensitive to ions and their efficiency is near 100%. We present a complete calibration of CR-39 track detector for protons, alpha particles, and carbon ions. We give measurements of their track diameters for energy ranging from hundreds of keV to a few MeV and for etching times between 1 and 8 h. We used these results to identify alpha particles in our experiments on proton-boron fusion reactions initiated by laser-accelerated protons. We show that their number clearly increases when the boron fuel is preformed in a plasma state.

  17. CR-39 track detector calibration for H, He, and C ions from 0.1-0.5 MeV up to 5 MeV for laser-induced nuclear fusion product identification.

    PubMed

    Baccou, C; Yahia, V; Depierreux, S; Neuville, C; Goyon, C; Consoli, F; De Angelis, R; Ducret, J E; Boutoux, G; Rafelski, J; Labaune, C

    2015-08-01

    Laser-accelerated ion beams can be used in many applications and, especially, to initiate nuclear reactions out of thermal equilibrium. We have experimentally studied aneutronic fusion reactions induced by protons accelerated by the Target Normal Sheath Acceleration mechanism, colliding with a boron target. Such experiments require a rigorous method to identify the reaction products (alpha particles) collected in detectors among a few other ion species such as protons or carbon ions, for example. CR-39 track detectors are widely used because they are mostly sensitive to ions and their efficiency is near 100%. We present a complete calibration of CR-39 track detector for protons, alpha particles, and carbon ions. We give measurements of their track diameters for energy ranging from hundreds of keV to a few MeV and for etching times between 1 and 8 h. We used these results to identify alpha particles in our experiments on proton-boron fusion reactions initiated by laser-accelerated protons. We show that their number clearly increases when the boron fuel is preformed in a plasma state. PMID:26329181

  18. Range imaging laser radar

    DOEpatents

    Scott, M.W.

    1990-06-19

    A laser source is operated continuously and modulated periodically (typically sinusoidally). A receiver imposes another periodic modulation on the received optical signal, the modulated signal being detected by an array of detectors of the integrating type. Range to the target determined by measuring the phase shift of the intensity modulation on the received optical beam relative to a reference. The receiver comprises a photoemitter for converting the reflected, periodically modulated, return beam to an accordingly modulated electron stream. The electron stream is modulated by a local demodulation signal source and subsequently converted back to a photon stream by a detector. A charge coupled device (CCD) array then averages and samples the photon stream to provide an electrical signal in accordance with the photon stream. 2 figs.

  19. Range imaging laser radar

    DOEpatents

    Scott, Marion W.

    1990-01-01

    A laser source is operated continuously and modulated periodically (typicy sinusoidally). A receiver imposes another periodic modulation on the received optical signal, the modulated signal being detected by an array of detectors of the integrating type. Range to the target determined by measuring the phase shift of the intensity modulation on the received optical beam relative to a reference. The receiver comprises a photoemitter for converting the reflected, periodically modulated, return beam to an accordingly modulated electron stream. The electron stream is modulated by a local demodulation signal source and subsequently converted back to a photon stream by a detector. A charge coupled device (CCD) array then averages and samples the photon stream to provide an electrical signal in accordance with the photon stream.

  20. Long-range connectomics.

    PubMed

    Jbabdi, Saad; Behrens, Timothy E

    2013-12-01

    Decoding neural algorithms is one of the major goals of neuroscience. It is generally accepted that brain computations rely on the orchestration of neural activity at local scales, as well as across the brain through long-range connections. Understanding the relationship between brain activity and connectivity is therefore a prerequisite to cracking the neural code. In the past few decades, tremendous technological advances have been achieved in connectivity measurement techniques. We now possess a battery of tools to measure brain activity and connections at all available scales. A great source of excitement are the new in vivo tools that allow us to measure structural and functional connections noninvasively. Here, we discuss how these new technologies may contribute to deciphering the neural code.

  1. Measurement of excitation function for 63Cu(n, p) 63Ni reaction up to En=15 MeV

    NASA Astrophysics Data System (ADS)

    Shibata, S.; Shibata, T.; Imamura, M.; Ohkubo, T.; Satoh, S.; Uwamino, Y.; Nogawa, N.; Baba, M.; Matsuyama, S.; Iwasaki, S.

    1999-01-01

    The excitation function for the 63Cu(n, p) 63Ni reaction were measured using neutrons produced by the T(p, n) reaction at En=˜1.5 MeV, D(d, n) at En=˜6.5 MeV and T(d, n) at En=˜14 MeV, respectively. Irradiations were performed using the dynamitron accelerator at the Fast Neutron Laboratory of Tohoku University. After irradiation, the nickel was separated by anion-exchange and solvent extraction. The 63Ni was measured by liquid scintillation method. The cross sections obtained were compared with the calculated values of JENDL-3.

  2. Further modeling of spur processes in the radiation chemistry of pure water and aqueous solutions. [14 MeV electron pulse and gamma radiation

    SciTech Connect

    Youngblade, W.

    1984-01-01

    All of the data from a comprehensive study of the kinetics of hydrated electron decay in the 14 MeV electron pulse radiolysis of pure water and aqueous solutions have been modeled within experimental error. The overlapping spur model utilized employs a constant energy fraction (0.2) of high, constant spur density (representing blobs/short tracks) and another constant energy fraction (0.8) of a low, variable spur density region (representing isolated spurs) whose spur density is proportional to the pulse dose. The model also contains a hydrated electron probability density displaced from the center of the spur. Adjustments made to fit experimental data from different aqueous solution pulse radiolysis studies have been minor and in agreement with independent experimental data. The spur model has been successfully tested against experimental hydrated electron data for 14 MeV electrons over a wide range of pulse doses (0.5-80 Gy), time regimes (10/sup -11/-10/sup -5/ s), and types of scavengers of spur transients (e/sub aq//sup -/, .OH, and H/sup +/). Modeling calculations were extended to include comparisons with pulsed 14 MeV electron and ..gamma.. radiolysis experiments which measured H/sub 2/, H/sub 2/O/sub 2/ and non-molecular product yields in the presence of various OH., H. and e/sub aq/-scavengers. Modeling parameters were unchanged from those used for the hydrated electron decay calculations described above. Non-molecular product yield calculations were in good agreement with experiment.

  3. Measurements of 15.11-MeV gamma-ray flux produced in the reactions C-12(p, p')-C-12*(15.11 MeV) and O-16(p, p' alpha)-C-12*(15.11 MeV)

    NASA Technical Reports Server (NTRS)

    Lapides, J. R.; Crannell, C. J.; Crannell, H.; Hornyak, W. F.; Seltzer, S. M.; Trombka, J. I.; Wall, N. S.

    1978-01-01

    The flux of 15.11 MeV gamma rays relative to the flux of 4.44 MeV gamma rays which are emitted from the corresponding states of C-12 are a sensitive measure of the spectrum of exciting particles in solar flares and other cosmic sources. Emission of 15.11 MeV gamma rays may result not only from the direct excitation of C-12 but also from the interaction O-16 (p,p' alpha) C-12* sup 15.11 MeV. Although the cross sections for the direct reaction was studied extensively, the cross section for the spallation interaction with O-16 is not reported in the literature. Preliminary measurements demonstrated the feasibility of measuring the production of 15.11 MeV gamma rays by proton interactions with O-16 using the University of Maryland cyclotron facility. For both carbon and oxygen targets the flux of 15.11 MeV gamma rays is being measured relative to the flux of 4.44 MeV gamma rays. The gamma ray emission from de-excitation of the giant dipole resonances is being measured.

  4. Alpha particle emission in the interaction of 12C with 59Co and 93Nb at incident energies of 300 and 400 MeV

    NASA Astrophysics Data System (ADS)

    Gadioli, E.; Cavinato, M.; Fabrici, E.; Gadioli Erba, E.; Birattari, C.; Mica, I.; Solia, S.; Steyn, G. F.; Förtsch, S. V.; Lawrie, J. J.; Nortier, F. M.; Stevens, T. G.; Connell, S. H.; Sellschop, J. P. F.; Cowley, A. A.

    1999-08-01

    The results of measured inclusive double differential cross section of α particles emitted in the interaction of 12C ions with 59Co and 93Nb at incident energies of 300 and 400 MeV are presented. The analysis of these data allows us to isolate the contributions of the different reaction mechanisms, thereby confirming previous conclusions of a comprehensive analysis of a large number of excitation function, forward recoil ranges and angular distributions of residues produced in the interaction of 12C with a target nucleus in the same mass range. In particular, the probabilities associated with α-particle reemission following incomplete fussion processes have been reaffirmed. Several refinements to the theoretical model proposed in earlier studies of the interaction of 12C with nuclei are presented.

  5. Optical absorption in fused silica at elevated temperatures during 1.5-MeV electron irradiation

    NASA Technical Reports Server (NTRS)

    Smith, A. B.

    1972-01-01

    An experimental determination of the optical transmission of Corning 7940 UV and Suprasil 1 and 2 fused silica has been made during 1.5-MeV electron bombardment. The fused silica reached temperatures ranging from 150 to 1000 C. The Lewis Research Center dynamitron provided electron current densities which corresponded to a dose rate of 2.6 to 20 Mrad/sec. The irradiation induced absorption was measured at 215.0, 270.0, and 450.0 nm (2150, 2700, 4500 A). The length of each irradiation was sufficient so that an equilibrium between radiation induced coloration and high temperature annealing was reached. The experimental results indicate a significant optical absorption, with values of the induced absorption coefficient at 215.0 nm (2150 A) of 14.5 to 2.2/cm, at 270.0 nm (2700 A) of 9.7 to 3.0/cm and at 450.0 nm (4500 A) of 3.7 to 0.5/cm. This would make the use of fused silica as the separating wall material in the nuclear light bulb propulsion concept questionable.

  6. Scattering process for the system 7Be + 58Ni at 23.2 MeV beam energy

    NASA Astrophysics Data System (ADS)

    Mazzocco, M.; Torresi, D.; Fierro, N.; Acosta, L.; Boiano, A.; Boiano, C.; Glodariu, T.; Guglielmetti, A.; La Commara, M.; Martel, I.; Mazzocchi, C.; Molini, P.; Pakou, A.; Parascandolo, C.; Parker, V. V.; Patronis, N.; Pierroutsakou, D.; Romoli, M.; Sanchez-Benitez, A. M.; Sandoli, M.; Signorini, C.; Silvestri, R.; Soramel, F.; Stiliaris, E.; Strano, E.; Stroe, L.; Zerva, K.

    2013-03-01

    We measured for the first time the scattering process of 7Be nuclei from a 58Ni target at 23.2 MeV beam energy. The experiment was performed at the Laboratori Nazionali di Legnaro (LNL, Italy), where the 7Be Radioactive Ion Beam was in-flight produced with the facility EXOTIC. Charged reaction products were detected by means of the detector array DINEX, arranged in a cylindrical configuration around the target to ensure a polar angle coverage in the ranges θcm = 40°-80° and 110°-150°. The scattering differential cross section was analyzed within the optical model formalism with the coupled-channel code FRESCO to extract the total reaction cross section. The result was compared with those obtained at lower beam energies in an earlier experiment performed at the University of Notre Dame (USA). At the present stage of our analysis, the two data sets were found to be not fully consistent each other.

  7. Dependence of the MeV ion-induced deformation of colloidal silica particles on the irradiation angle

    NASA Astrophysics Data System (ADS)

    Cheang-Wong, J. C.; Morales, U.; Reséndiz, E.; López-Suárez, A.; Rodríguez-Fernández, L.

    2008-06-01

    Colloidal silica particles are being intensively studied due to their potential applications in catalysis, intelligent materials, optoelectronic devices and coating technology. For this work, spherical sub-micrometer-sized silica particles were prepared by the Stöber process and deposited onto silicon wafers. The samples were then irradiated at room temperature with Si ions at 8 MeV and fluences up to 5 × 1015 Si/cm2, under different angles θ, ranging from 15° to 75° with respect to the sample normal. The size, size distribution and shape of the silica particles were determined using scanning electron microscopy. After the Si irradiation the as-prepared spherical silica particles turned into ellipsoidal particles, as a result of the increase of the particle dimension perpendicular to the ion beam and a decrease in the direction parallel to the ion beam. This effect increases with the ion fluence, and the dependence of the deformation rate on the irradiation angle is discussed.

  8. Chromosome aberrations in human lymphocytes induced by 250 MeV protons: effects of dose, dose rate and shielding

    NASA Technical Reports Server (NTRS)

    George, K.; Willingham, V.; Wu, H.; Gridley, D.; Nelson, G.; Cucinotta, F. A.

    2002-01-01

    Although the space radiation environment consists predominantly of energetic protons, astronauts inside a spacecraft are chronically exposed to both primary particles as well as secondary particles that are generated when the primary particles penetrate the spacecraft shielding. Secondary neutrons and secondary charged particles can have an LET value that is greater than the primary protons and, therefore, produce a higher relative biological effectiveness (RBE). Using the accelerator facility at Loma Linda University, we exposed human lymphocytes in vitro to 250 MeV protons with doses ranging from 0 to 60 cGy at three different dose rates: a low dose rate of 7.5 cGy/h, an intermediate dose rate of 30 cGy/h and a high dose rate of 70 cGy/min. The effect of 15 g/cm2 aluminum shielding on the induction of chromosome aberrations was investigated for each dose rate. After exposure, lymphocytes were incubated in growth medium containing phytohemagglutinin (PHA) and chromosome spreads were collected using a chemical-induced premature chromosome condensation (PCC) technique. Aberrations were analyzed using the fluorescence in situ hybridization (FISH) technique with three different colored chromosome-painting probes. The frequency of reciprocal and complex-type chromosome exchanges were compared in shielded and unshielded samples. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

  9. Possible evidence for the SIGMA* resonance with J{sup P}=1/2{sup -} around 1380 MeV

    SciTech Connect

    Wu Jiajun; Dulat, S.; Zou, B. S.

    2010-04-15

    The unquenched quark models predict the new particle SIGMA* with spin-parity J{sup P}=1/2{sup -} and its mass is around the well-established SIGMA*(1385) with J{sup P}=3/2{sup +}. Here, by using the effective Lagrangian approach, we study K{sup -}p->LAMBDApi{sup -}pi{sup +} reaction at the range of LAMBDA*(1520) peak, comparing the resulting total cross section, and pi{sup +}pi{sup -}, LAMBDApi{sup +}, LAMBDApi{sup -} invariant squared mass distributions for various incident K{sup -} momenta, as well as the production angular distribution of the LAMBDA with the data from the Lawrence Berkeley Laboratory 25-inch hydrogen bubble chamber; we find that, apart from the existing resonance SIGMA*(1385) with J{sup P}=3/2{sup +}, there is evidence for possible existence of the new resonance SIGMA* with J{sup P}=1/2{sup -} around 1380 MeV. Higher statistic data on relevant reactions are needed to clarify the situation.

  10. Improve the physical and chemical properties of biocompatible polymer material by MeV He ion beam

    NASA Astrophysics Data System (ADS)

    Abdul-Kader, A. M.; El-Gendy, Y. A.; Al-Rashdy, Awad A.

    2012-07-01

    There is a high interest in improving the hydrophilicity of polymer surfaces due to their wide use for technological purposes. In this study Ultra High Molecular Weight Polyethylene (UHMWPE) as a biocompatible material was bombarded with 1 MeV He ions to the fluences ranging from 1×1013 to 5×1014 cm-2. The pristine and ion beam modified samples were investigated by photoluminescence (PL), ultraviolet-visible (UV-vis) spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR). The changes of wettability and surface free energy were determined by the contact angle measurements. The obtained results showed that the ion bombardment induced decrease in integrated luminescence intensity and decrease in the transmittance with increase of ion fluence as well. This is might be attributed to degradation of polymer surface and/or creation of new electronic levels in the forbidden gap. The FTIR spectral studies indicate that the ion beam induces chemical modifications within the bombarded UHMWPE. Formation of carbonyl groups (C=O) on the polymer surface was studied. Direct relationship of the wettability and surface free energy of the bombarded polymer with the ion fluences was observed.

  11. LCS/CINDER`90 accelerator tunnel activation calculations for the APT 1700-MeV accelerator tunnel

    SciTech Connect

    Court, J.D.; Snow, E.C.; Wilson, W.B.; Pitcher, E.R.

    1998-09-01

    Calculations have been done to determine the amount of activation in the linac components and tunnel air for the Accelerator Production of Tritium 1700-MeV superconducting linac. Proton transport is accomplished through the use of the LAHET Code System. Particle production and depletion from proton and high-energy neutron reactions, calculated in LAHET, as well as low-energy neutron fluxes calculated by MCNP, are passed to the radionuclide production code CINDER`90 to determine the source terms at various times after irradiation. The upper limit on total air activation based on conservative assumptions, for the entire tunnel air volume, was found to be 4.77 Ci after a nine-month irradiation. This is reduced to 0.09 Ci after a 10-hour cooling off period. The total activation for the full 1-km of beamline components was found to be less than 4 kCi, with the half-lives of the highest contributors ranging from 12 years to 2 minutes. This beamline component activation calculation was done for an irradiation time of 40 years, which is the anticipated lifetime of the superconducting linac.

  12. Neutron range spectrometer

    DOEpatents

    Manglos, Stephen H.

    1989-06-06

    A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are collimnated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. The computer solves the following equation in the analysis: ##EQU1## where: N(x).DELTA.x=the number of neutron interactions measured between a position x and x+.DELTA.x, A.sub.i (E.sub.i).DELTA.E.sub.i =the number of incident neutrons with energy between E.sub.i and E.sub.i +.DELTA.E.sub.i, and C=C(E.sub.i)=N .sigma.(E.sub.i) where N=the number density of absorbing atoms in the position sensitive counter means and .sigma. (E.sub.i)=the average cross section of the absorbing interaction between E.sub.i and E.sub.i +.DELTA.E.sub.i.

  13. The first SEPServer event catalogue ~68-MeV solar proton events observed at 1 AU in 1996-2010

    NASA Astrophysics Data System (ADS)

    Vainio, Rami; Valtonen, Eino; Heber, Bernd; Malandraki, Olga E.; Papaioannou, Athanasios; Klein, Karl-Ludwig; Afanasiev, Alexander; Agueda, Neus; Aurass, Henry; Battarbee, Markus; Braune, Stephan; Dröge, Wolfgang; Ganse, Urs; Hamadache, Clarisse; Heynderickx, Daniel; Huttunen-Heikinmaa, Kalle; Kiener, Jürgen; Kilian, Patrick; Kopp, Andreas; Kouloumvakos, Athanasios; Maisala, Sami; Mishev, Alexander; Miteva, Rositsa; Nindos, Alexander; Oittinen, Tero; Raukunen, Osku; Riihonen, Esa; Rodríguez-Gasén, Rosa; Saloniemi, Oskari; Sanahuja, Blai; Scherer, Renate; Spanier, Felix; Tatischeff, Vincent; Tziotziou, Kostas; Usoskin, Ilya G.; Vilmer, Nicole

    2013-03-01

    SEPServer is a three-year collaborative project funded by the seventh framework programme (FP7-SPACE) of the European Union. The objective of the project is to provide access to state-of-the-art observations and analysis tools for the scientific community on solar energetic particle (SEP) events and related electromagnetic (EM) emissions. The project will eventually lead to better understanding of the particle acceleration and transport processes at the Sun and in the inner heliosphere. These processes lead to SEP events that form one of the key elements of space weather. In this paper we present the first results from the systematic analysis work performed on the following datasets: SOHO/ERNE, SOHO/EPHIN, ACE/EPAM, Wind/WAVES and GOES X-rays. A catalogue of SEP events at 1 AU, with complete coverage over solar cycle 23, based on high-energy (~68-MeV) protons from SOHO/ERNE and electron recordings of the events by SOHO/EPHIN and ACE/EPAM are presented. A total of 115 energetic particle events have been identified and analysed using velocity dispersion analysis (VDA) for protons and time-shifting analysis (TSA) for electrons and protons in order to infer the SEP release times at the Sun. EM observations during the times of the SEP event onset have been gathered and compared to the release time estimates of particles. Data from those events that occurred during the European day-time, i.e., those that also have observations from ground-based observatories included in SEPServer, are listed and a preliminary analysis of their associations is presented. We find that VDA results for protons can be a useful tool for the analysis of proton release times, but if the derived proton path length is out of a range of 1 AU < s ≲ 3 AU, the result of the analysis may be compromised, as indicated by the anti-correlation of the derived path length and release time delay from the associated X-ray flare. The average path length derived from VDA is about 1.9 times the nominal length

  14. Single event upsets calculated from new ENDF/B-VI proton and neutron data up to 150 MeV

    SciTech Connect

    Chadwick, M.B.; Normand, E.

    1999-06-01

    Single-event upsets (SEU) in microelectronics are calculated from newly-developed silicon nuclear reaction recoil data that extend up to 150 MeV, for incident protons and neutrons. Calculated SEU cross sections are compared with measured data.

  15. Gamma rays of 1-30 MeV from the Vela Pulsar PSR 0833-45

    NASA Technical Reports Server (NTRS)

    Tumer, T.; Long, J.; Oneill, T.; Zych, A.; White, R. S.; Dayton, B.

    1983-01-01

    Results are reported for observations of gamma rays of 1-30 MeV from the Vela Pulsar PSR 0833 - 45 carried out with the UCR double scatter gamma ray telescope on a balloon launched from Alice Springs, Australia on November 10, 1981. An integrated flux of (5.3 + or - 1.3) x 10 to the -4th photons/sq cm/s is found for the Vela region above 2 MeV. This value, together with those for the energy intervals of 2-4, 4-7, and 7-15 MeV are in reasonable agreement with the power law found by COS-B at energies above 50 MeV. A sky contour map of the fluxes is shown.

  16. Elastic and inelastic neutron scattering from /sup 27/Al at 11, 14, and 17 MeV

    SciTech Connect

    Whisnant, C.S.; Dave, J.H.; Gould, C.R.

    1984-11-01

    Fast neutron scattering cross sections have been measured for /sup 27/Al using a neutron time-of-flight facility. Angular distributions were measured at angles from 20/sup 0/ to 160/sup 0/ in 5/sup 0/ increments, at incident neutron energies of 11, 14, and 17 MeV. Data are presented for elastic scattering and for inelastic scattering to the sum of the 0.84 and 1.01 MeV states, the 2.21 MeV state, and the sum of the 2.73, 2.98, and 3.00 MeV states. After correcting for compound nucleus effects, the elastic scattering cross sections are well reproduced by the spherical optical model using a linear energy dependence in the real well depth. The inelastic data are interpreted with a coupled channels calculation and the excited core model.

  17. Compton scattering in jets: A mechanism for approximately 0.4 and less than or approximately 0.2 MeV line production

    NASA Technical Reports Server (NTRS)

    Skibo, J. G.; Dermer, C. D.; Ramaty, R.

    1994-01-01

    We show that gamma-ray line emission at approximately 0.4 and less than or approximately 0.2 MeV can be produced by Compton scattering of beamed radiation in the jets of Galactic black hole candidates. This mechanism has the novel feature of not invoking the presence of e(exp +)-e(exp -) pairs. To produce the two lines, we employ a symmetric double-sided jet with bulk flow velocity of about 0.5c and incident beam radiation with a hard energy spectrum. We show that the two lines can be seen at viewing-angle cosines relative to the jet ranging from 0.2 to 0.6. This comprises 40% of the total solid angle. In addition, the line radiation is approximately 10% polarized. Depending on the bulk flow and viewing angle, the model can produce lines at other energies as well. In particular, a broad feature near 1 MeV can be seen by viewing the jet close to its axis. Our model can also accommodate single-line spectra if the beamed gamma-ray emission or the jets themselves are asymmetric.

  18. Energy measurement of prompt fission neutrons in 239Pu(n,f) for incident neutron energies from 1 to 200 MeV

    SciTech Connect

    Haight, Robert C; Devlin, Matthew J; Nelson, Ronald O; O' Donnell, John M; Chatillon, Audrey; Granier, Thierry; Taieb, Julien; Belier, Gilbert; Laurent, Benoit; Noda, Shusaku

    2010-01-01

    An experimental campaign was started in 2002 in the framework of a collaboration belween CEA-DAM and the Los Alamos National Laboratory to measure the prompt fission neutron spectra (PFNS) for incident neutron energies from 1 to 200 MeV with consistent error uncertainties over the whole energy range. The prompt neutron spectra in {sup 235,238}U(n,f) and {sup 237}Np(n,f) have been already studied successfully. A first attempt to characterize the prompt neutrons emitted during the fission of the {sup 239}Pu was done in 2007. This contribution will focus on the results obtained during the final experiment to measure the PFNS in {sup 239}Pu(n,f) performed in 2008. Prompt fission neutron spectra in the neutron-induced fission of {sup 239}Pu have been measured for incident neutron energies from 1 to 200 MeV at the Los Alamos Neutron Science Center. Mean energies obtained from the spectra are discussed and compared to theoretical model calculation.

  19. Dosimetry for Neutrons from 0.25 to 15 MeV by the Measurement of Linear Energy Transfer Distributions for Secondary Charged Particles in CR-39 Plastic

    NASA Astrophysics Data System (ADS)

    Tawara, Hiroko; Eda, Kazuyoshi; Sanami, Toshiya; Sasaki, Shinichi; Takahashi, Kazutoshi; Sonkawade, Rajendra; Nagamatsu, Aiko; Kitajo, Keiichi; Kumagai, Hidenori; Doke, Tadayoshi

    2008-03-01

    In the radiation fields of high energy accelerator facilities, high-altitude aircraft and space flights, high-energy neutron dosimetry of ˜20 MeV or more is a significant issue for radiological protection. We studied the feasibility of experimental measurements of linear energy transfer (LET) distributions for secondary charged particles induced by fast neutrons using CR-39 plastic nuclear track detectors. In order to investigate a method of analyzing the CR-39 detectors that is appropriate for fast neutron dosimetry, two-layer CR-39 stacks were exposed to monochromatic neutrons (0.25, 0.55, 5, and 15 MeV) at the Fast Neutron Laboratory of Tohoku University in Japan. We also conducted Monte Carlo calculations to estimate the detection efficiency of the CR-39 detector for recoil protons. The CR-39 detectors treated by single-step chemical etching were used to obtain LET distributions for LET > 10 keV/µm-water. The results indicated that measurements of short-range particles are very important for obtaining the correct LET distributions. Using the measured LET distributions, we calculated neutron sensitivities, absorbed doses and dose equivalents based on the ICRP 60 Q-L relation and averaged quality factors. The dose equivalents were compared with the neutron fluence-to-dose equivalent conversion factors given by ICRP 74 and the averaged quality factors were compared with weighting factors given by ICRP 60 and ICRP 92.

  20. [BIOLOGICAL EFFECTIVENESS OF FISSION SPECTRUM NEUTRONS AND PROTONS WITH ENERGIES OF 60-126 MEV DURING ACUTE AND PROLONGED IRRADIATION].

    PubMed

    Shafirkin, A V

    2015-01-01

    Neutrons of the fission spectrum are characterized by relatively high values of linear energy transfer (LET). Data about their effects on biological objects are used to evaluate the risk of delayed effects of accelerated ions within the same LET range that serve as an experimental model of the nuclei component of galactic cosmic rays (GCR). Additionally, risks of delayed consequences to cosmonaut's health and average lifetime from certain GCR fluxes and secondary neutrons can be also prognosticated. The article deals with comparative analysis of the literature on reduction of average lifespan (ALS) of animals exposed to neutron reactor spectrum, 60-126 MeV protons, and X- and γ-rays in a broad range of radiation intensity and duration. It was shown that a minimal lifespan reduction by 5% occurs due to a brief exposure to neutrons with the absorbed dose of 5 cGy, whereas same lifespan reduction due to hard X- and γ-radiation occurs after absorption of a minimal dose of 100 cGy. Therefore, according to the estimated minimal ALS reduction in mice, neutron effectiveness is 20-fold higher. Biological effectiveness of protons as regards ALS reduction is virtually equal to that of standard types of radiation. Exposure to X- and γ-radiation with decreasing daily doses, and increasing number of fractions and duration gives rise to an apparent trend toward a less dramatic ALS reduction in mice; on the contrary, exposure to neutrons of varying duration had no effect on threshold doses for the specified ALS reductions. Factors of relative biological effectiveness of neutrons reached 40. PMID:26934784