WorldWideScience

Sample records for 50-130 mev range

  1. SCANDAL -- A facility for elastic neutron scattering studies in the 50--130 MeV range

    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 facility of the The Svedberg Laboratory, Uppsala. It is primarily intended for studies of elastic neutron scattering, but can be used for the (n,p) and (n,d) reaction experiments as well. The performance of the spectrometer is illustrated in measurements of the (n,p) and (n,n) reactions on 1H and 12C. In addition, the neutron beam facility is described in some detail

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

    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.

  3. High energy resolution electron beam spectrometer in the MeV range

    Two electron spectrometers have been developed for the characterisation of scintillating counters with MeV range electrons. These spectrometers offer a monoenergetic electron beam ranging from 0.4 to 1.8 MeV with an energy resolution (FWHM) of 1.0 ± 0.2% at 1 MeV and a linearity better than 2%. The transverse profile of the beams consists of a typical 3.0 mm Gaussian width. These electron beams can automatically scan surfaces up to 60 × 200 cm2 in 1 mm increments. They have been used in the calorimeter module development for the SuperNEMO experiment

  4. Theoretical study of cylindrical energy analyzers for MeV range heavy ion beam probes

    A cylindrical energy analyzer with drift spaces is shown to have a second order focusing for beam incident angle when the deflection angle is properly chosen. The analyzer has a possibility to be applied to MeV range heavy ion beam probes, and will be also available for accurate particle energy measurements in many other fields. (author)

  5. Recoil proton polarization of neutral pion photoproduction from proton in the energy range between 400 MeV and 1142 MeV

    The recoil proton polarization of the reaction γp → π0p were measured at a C.M. angle of 1000 for incident photon energies between 451 and 1106 MeV, and at an angle of 1300 for energies from 400 MeV to 1142 MeV. One photon decayed from a π0-meson and a recoil proton were detected in coincidence. Two kinds of polarization scatterers were employed. In the range of proton kinetic energy less than 420 MeV and higher than 346 MeV, carbon plates and liquid hydrogen were used for determining the polarization. Results are compared with recent phenomenological analyses. From the Comparison between the present data and the asymmetry data given by the polarized target, the contribution of the invariant amplitudes A3 can be estimated to be small at 1000. (author)

  6. Implants of aluminum in the 50-120 MeV energy range into silicon

    Al ions in the 50-120 MeV energy range were implanted in Si substrates for fluences varying between 1 x 1014 and 3.5 x 1015 /cm2. The electrical and chemical Al distributions were obtained by spreading resistance profilometry and secondary ion mass spectroscopy and the two principal moments, Rp and ΔRp, were measured. On low resistivity samples, ρ = 0.01 Ω cm, the disorder profile induced by the 100 MeV Al implant was determined from the electrical measurement of the inactivated bulk dopant (boron) distribution. The diffusion coefficient of Al implanted into floating-zone silicon was extracted from the electrical profiles after thermal treatments in the 1000-1290degC temperature range with the result D = 7.4 exp[-3.42(eV)/kT](cm2/s). (orig.)

  7. Implants of aluminum in the 50-120 MeV energy range into silicon

    La Ferla, A.; Torrisi, L.; Galvagno, G.; Rimini, E. (Dipt. di Fisica, Univ. di Catania (Italy)); Ciavola, G. (Lab. Nazionale del Sud, INFN, Catania (Italy)); Carnera, A.; Gasparotto, A. (Dipt. di Fisica, Univ. di Padova (Italy))

    1993-01-01

    Al ions in the 50-120 MeV energy range were implanted in Si substrates for fluences varying between 1 x 10[sup 14] and 3.5 x 10[sup 15] /cm[sup 2]. The electrical and chemical Al distributions were obtained by spreading resistance profilometry and secondary ion mass spectroscopy and the two principal moments, R[sub p] and [Delta]R[sub p], were measured. On low resistivity samples, [rho] = 0.01 [Omega] cm, the disorder profile induced by the 100 MeV Al implant was determined from the electrical measurement of the inactivated bulk dopant (boron) distribution. The diffusion coefficient of Al implanted into floating-zone silicon was extracted from the electrical profiles after thermal treatments in the 1000-1290degC temperature range with the result D = 7.4 exp[-3.42(eV)/kT](cm[sup 2]/s). (orig.).

  8. Implants of aluminum in the 50-120 MeV energy range into silicon

    La Ferla, A.; Torrisi, L.; Galvagno, G.; Rimini, E.; Ciavola, G.; Carnera, A.; Gasparotto, A.

    1993-01-01

    Al ions in the 50-120 MeV energy range were implanted in Si substrates for fluences varying between 1 × 10 14 and 3.5 × 10 15/cm 2. The electrical and chemical Al distributions were obtained by spreading resistance profilometry and secondary ion mass spectroscopy and the two principal moments, Rp and ΔRp, were measured. On low resistivity samples, τ = 0.01 Ω cm, the disorder profile induced by the 100 MeV Al implant was determined from the electrical measurement of the inactivated bulk dopant (boron) distribution. The diffusion coefficient of Al implanted into floating-zone silicon was extracted from the electrical profiles after thermal treatments in the 1000-1290°C temperature range with the result D = 7.4 exp[ {-3.42( eV) }/{kT}] {( cm2}/{s) }.

  9. The H(n,n) cross section in the 20 MeV to 350 MeV range

    The differential H(n,n) cross section has been used as a standard relative to which other neutron emission cross sections, e.g., elastic or inelastic scattering, have been measured in several Mev region and these measured values are compared with the VL40 solution of R. Arndt, and R.L. Workman, Nuclear Data Standards for Nuclear Measurements, H. Conde (ed.). NEANDC-311, INDC (SEC)-101, 1992, p. 17. For hydrogen, the differential elastic scattering cross section can be directly related to the total cross section, since no other channels of importance are open below the pion production threshold at about 280 MeV (the capture and Bremsstrahlung cross section are very small). 16 refs, 3 figs

  10. Absolute calibration of neutron detectors in the 10--30 MeV energy range

    A central problem in fast neutron research is that of finding the absolute efficiency of neutron detectors. Using the associated particle method for this purpose, we have designed a chamber to count He particles from the D(d,n)3He or the T(d,n)4He reaction in coincidence with neutron events. The reactions take place in deuterium or tritium gas and a ΔE solid state counter at 800, 650, or 430 to the 2-10 MeV deuteron beam direction detects the He particles with 100 percent efficiency. To reduce background we allow the deuterons to pass out of the gas chamber through a Ni window and stop the beam approximately 150 cm from the counters. With the D(d,n)3He reaction we have obtained approximately 2 percent efficiency calibration of the central portion of a liquid scintillator in the 9-10 MeV energy range. With the T(d,n) reaction this calibration can be extended to approximately 27 MeV and the efficiency can be mapped out as a function of position in the scintillator

  11. Study of the thermal oxidation of titanium and zirconium under argon ion irradiation in the low MeV range (E = 15 MeV)

    We have shown that argon ion irradiation between 1 and 15 MeV produces damage on both titanium and zirconium surfaces, taking the form of accelerated oxidation and/or craterization effects, varying as a function of the projectile energy and the annealing atmosphere (temperature and pressure) simulating the environmental conditions of the fuel/cladding interface of PWR fuel rods. Using AFM, we have shown that the titanium and zirconium surface is attacked under light argon ion bombardment at high temperature (up to 500 C) in weakly oxidizing medium (under rarefied dry air pressure ranging from 5,7 10-5 Pa to 5 10-3 Pa) for a fixed fluence of about 5 1014 ions.cm-2. We observed the formation of nano-metric craters over the whole titanium surface irradiated between 2 and 9 MeV and the whole zirconium surface irradiated at 4 MeV, the characteristics of which vary depending on the temperature and the pressure. In the case of the Ar/Ti couple, the superficial damage efficiency increases when the projectile energy decreases from 9 to 2 MeV. Moreover, whereas the titanium surface seems to be transparent under the 15-MeV ion beam, the zirconium surface exhibits numerous micrometric craters surrounded by a wide halo. The crater characteristics (size and superficial density) differ significantly from that observed both in the low energy range (keV) where the energy losses are controlled by ballistic collisions (Sn) and in the high energy range (MeV - GeV) where the energy losses are controlled by electronic excitations (Se), which was not completely unexpected in this intermediate energy range for which combined Sn - Se stopping power effects are possibly foreseen. Using XPS associated to ionic sputtering, we have shown that there is an irradiation effect on thermal oxidation of titanium, enhanced under the argon ion beam between 2 and 9 MeV, and that there is also an energy effect on the oxide thickness and stoichiometry. The study conducted using Spectroscopic Ellipsometry

  12. Calculation of Multisphere Neutron Spectrometer Response Functions in Energy Range up to 20 MeV

    Martinkovic, J

    2005-01-01

    Multisphere neutron spectrometer is a basic instrument of neutron measurements in the scattered radiation field at charged-particles accelerators for radiation protection and dosimetry purposes. The precise calculation of the spectrometer response functions is a necessary condition of the propriety of neutron spectra unfolding. The results of the response functions calculation for the JINR spectrometer with LiI(Eu) detector (a set of 6 homogeneous and 1 heterogeneous moderators, "bare" detector within cadmium cover and without it) at two geometries of the spectrometer irradiation - in uniform monodirectional and uniform isotropic neutron fields - are given. The calculation was carried out by the code MCNP in the neutron energy range 10$^{-8}$-20 MeV.

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

    Pusztai, István; Kazakov, Yevgen O; Fülöp, Tünde

    2016-01-01

    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 [Ye. O. 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 results 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.

  14. Calculation of multisphere neutron spectrometer response functions in energy range up to 20 MeV

    Multisphere neutron spectrometer is a basic instrument of neutron measurements in the scattered radiation field at charged-particles accelerators for radiation protection and dosimetry purposes. The precise calculation of the spectrometer response functions is a necessary condition of the propriety of neutron spectra unfolding. The results of the response functions calculation for the JINR spectrometer with LiI(Eu) detector (a set of 6 homogeneous and 1 heterogeneous moderators, 'bare' detector within cadmium cover and without it) at two geometries of the spectrometer irradiation - in uniform monodirectional and uniform isotropic neutron fields - are given. The calculation was carried out by the code MCNP in the neutron energy range 10-8 - 20 MeV

  15. Neutron production in the energy range 7 to 12 MeV using a gas-target

    A gas-target for operation at a tandem-accelerator is described. Using the DD-reaction, an energy range of neutrons between 7 and 12 MeV can be realised. Construction and operation are described in detail. For neutron energies below 9 MeV the neutron source is almost monoenergetic; above this energy the deuteron break-up limits the monoenergetic behaviour. (author)

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

    Mclean, Thomas D [Los Alamos National Laboratory; Justus, Alan L [Los Alamos National Laboratory; Gadd, S Milan [Los Alamos National Laboratory; Olsher, Richard H [RP-2; Devine, Robert T [RP-2

    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.

  17. Simulation of Neutron Production in Selected Targets by Proton and Deuteron Beam in Energy Range from 10 MeV to 75 MeV

    Initial inter-comparison study of simulation of neutron production by beam of protons and deuterons in different target materials, in energy range from 10 MeV to 75 MeV, is shown in the paper. An idealised cylindrical (diameter = height = 2.5 cm) target is bombarded, along the central axis, perpendicularly at target base, by an infinite thin particle beam. Simulation is carried out for the target surrounded by void, i.e., the 'return effect' from surrounding materials in a real system is not encountered. The study is carried out using Monte Carlo based computer codes for intermediate and high-energy nucleon transport: LCS, ver.2.7 (LANL, USA) and SHIELD (INR, Russia). Yield (total number of neutrons in 4 , per incident particle) and spectrum of neutrons escaping the target surfaces are determined for different targets made from 208Pb/Pb, 238U/U, 184W/W, Be and 7Li. Maximum neutron yield, near 30%, is calculated for proton beam energy of 75 MeV bombarding 238U/U target, shaped as mentioned above. Generally, neutron yield for deuteron beam is less than neutron yield for proton beam of the same energy for targets made from high-Z nuclides. The opposite conclusion is derived for targets made from low-Z nuclides. (author)

  18. Dual sightline measurements of MeV range deuterons with neutron and gamma-ray spectroscopy at JET

    Eriksson, J.; Nocente, M.; Binda, F.;

    2015-01-01

    with predictions from ab initio models of RF heating at multiple harmonics. The results presented in this paper are of relevance for the development of advanced diagnostic techniques for MeV range ions in high performance fusion plasmas, with applications to the experimental validation of RF heating codes and...

  19. Neutron cross-sections for 55Mn in the energy range from 0.2 to 22 MeV

    RAHMAN, Abul Khaer Mohammad Rezaur

    2012-01-01

    Neutron total and differential elastic scattering cross-sections for 55Mn nucleus was calculated from different global spherical optical potential (SOP) sets for different neutron energies ranging from 0.2 MeV to 22 MeV using the well known computer program SCAT-2 on an IBM PC-AT. In addition, the angular distributions of elastically scattered neutrons at different neutron energies were calculated. The results were compared with those of the experimental data obtained from the EXFOR d...

  20. Measurement of Neutron Activation Cross Sections on Mo isotopes in the Energy Range from 7 MeV to 15 MeV

    Semkova Valentina; Nolte Ralf

    2014-01-01

    An experimental study of the 92Mo(n,p)92Nbm, 92Mo(n,α)89Zr, 95Mo(n,p)95Nbm, 95Mo(n,p)95Nb, 96Mo(n,p)96Nb, 97Mo(n,p)97Nb, 98Mo(n,p)98Nbm, 98Mo(n,a)95Zr, 100Mo(n,α) 97Zr, and 92Mo(n,2n)99Mo activation reaction cross sections were carried out in the 7-15 MeV energy range at the CV28 compact cyclotron at Physikalisch-Technische Bundesanstalt, Braunschweig. The PTB TOF spectrometer with a D(d,n) source is well suited for this difficult energy range were significant correction for non-monoenergetic...

  1. Absolute calibration of neutron detectors in the 10- to 30-MeV range

    An experiment was conducted to determine the forward scattering of neutrons from protons at energies below 30 MeV. The associated particle method was used to determine the absolute efficiency of the neutron detector. The reaction chamber for absolute calibration is diagrammed. (U.S.)

  2. A measurement of auroral electrons in the 1–10 MeV range

    Gils, J.N. van; Beek, H.F. van; Fetter, L.D. de; Hendrickx, R.V.

    1969-01-01

    Particle fluxes have been measured by means of shielded Geiger-Müller telescopes mounted m a rocket, which was launched from ESRANGE(Kiruna) into a diffuse aurora. The analysis of the dependence of the counting rates on altitude indicates that a weak flux of energetic electrons, 1–10 MeV, has been d

  3. Long-Range Alpha Particle Emission in the Fission of U235 by 3-MeV Neutrons

    The energy and angular distribution of long-range alpha particles emitted in the fission of U235 induced by 3-MeV neutrons have been measured. The alpha panicles were detected by solid-state detector and the fission fragments were detected by a gas scintillation counter. The neutrons were produced by the T (p, n) He3 reaction using a 5.5- MeV Van de Graaff accelerator. About 3000 fission events accompanied by the emission of a high-energy alpha panicle were recorded. The most probable energy of the alpha particles is between 15-16 MeV. and the energy distribution has a full width at half maximum of about D MeV, which is the same as observed in tliermal- neutron fission. The angular distribution of the long-range alpha panicles with respect to the incident neutron direction was found to be forward-peaked, in agreement with previous work on alpha emission in 14-MeV neutron-induced fission of LP. At angles of 0° and 90° with respect to the incident neutron direction the alpha panicles were detected with an angular spread of about ± 25°. The anisotropy [Nα(0°)/ Nα(90°)] was found to be 1.320 ± 0.12. This value is in agreement with the anisotropy calculated on the basis of statistical evaporation of panicles. The results of the present investigation are consistent with the hypothesis that the emission of long-range alpha panicles in fission is an evaporation process. The implications of the results of this work and of other recent investigations on long-range alpha emission are discussed. (author)

  4. Reaction cross sections for protons in the energy range 220-570 MeV

    Renberg, P U; Measday, D F; Pepin, M; Serre, Claude; Schwaller, P

    1972-01-01

    Proton reaction cross sections have been measured for targets of natural isotopic abundance of the following elements and compounds: He, Be, C, Al, Fe, Cu, Ge, Sn, Pb, H/sub 2/O, B/sub 4/C and NaI. Data for proton energies between 220 and 570 MeV have been obtained with two types of transmission-counter assembly. The total errors are of the order of +or-3%. A slight increase of the reaction cross sections with energy is observed for most of the elements studied. The results interpreted in terms of the semi-classical theory of reaction cross section as function of energy clearly demonstrate the onset of pion- production above 250 MeV. (32 refs).

  5. Compton scattering from 12C using tagged photons in the energy range 65 - 115 MeV

    Myers, L S; Preston, M F; Anderson, M D; Annand, J R M; Boselli, M; Briscoe, W J; Brudvik, J; Capone, J I; Feldman, G; Fissum, K G; Hansen, K; Henshaw, S S; Isaksson, L; Jebali, R; Kovash, M A; Lewis, K; Lundin, M; MacGregor, I J D; Middleton, D G; Mittelberger, D E; Murray, M; Nathan, A M; Nutbeam, S; O'Rielly, G V; Schröder, B; Seitz, B; Stave, S C; Weller, H R

    2014-01-01

    Elastic scattering of photons from 12C has been investigated using quasi-monoenergetic tagged photons with energies in the range 65 - 115 MeV at laboratory angles of 60 deg, 120 deg, and 150 deg at the Tagged-Photon Facility at the MAX IV Laboratory in Lund, Sweden. A phenomenological model was employed to provide an estimate of the sensitivity of the 12C(g,g)12C cross section to the bound-nucleon polarizabilities.

  6. DM2 results on e+e- annihilation into multihadrons in the 1350-2400 MeV energy range

    We present preliminary results on the study of e+e- annihilation into π+π-π+π-, π+π-π0π0, π+π-π0, π+π-π+π-π0, K+K-π+π- and Ks0K±π-+ in the 1350-2400 MeV energy range. Data have been collected with the DM2 detector at DCI, the Orsay colliding ring, and refer to about 2 pb-1 integrated luminosity

  7. Incomplete fusion studies using recoil range distribution measurement for 16O + 156Gd system at 86 MeV

    In the present study we have made an attempt to measure the forward recoil range distributions (RRDs) of the residues produced in an interaction of 16O with 156Gd at 86 MeV to get a more clear picture of linear momentum transferred from projectile to target. The measurement of RRD can also be used to distinguish different ICF processes where the same residue may be formed by fusion of different fragments in the projectile break-up with target followed by the emission of different groups of particle. To the best of our knowledge RRDs for this system has been measured for the first time

  8. Evaluation of 242Pu data for the incident neutron energy range 5-20 MeV

    Models, procedures and parameters are presented for the calculation of neutron cross sections, the neutron angular distributions and the neutron energy distributions of 242Pu in the energy range 5-20 MeV. The interaction takes place through direct interaction and compound nucleus mechanism. For heavy deformed nucleus the direct interaction was treated with the coupled channel process, using the ECIS code. For the compound nucleus mechanism, a statistical treatment was used for fission, neutron elastic and inelastic scattering, radiative capture, (n,2n), (n,3n), (n,4n) cross section calculations, using the GNASH code. (R.P.)

  9. A calculation on n-D scattering cross sections in the energy range 0 to 20 MeV

    A calculation on n-D scattering cross sections with phase shift analysis is carried out in the neutron energy range of 0 to 20 MeV. An optimum set of parameters are obtained by fitting the experimental data which include total, (n,2n) and differential cross section of n-D scattering. The comparisons were made between this calculated results and previous works. It was showed that the obtained differential elastic cross sections are in good agreement with the experimental values

  10. Gamma Ray Buildup Factor for Finite Media in Energy Range (4-10) MeV for Al and Pb

    A computer program based on Monte Carlo method had been designed and written in visual basic computer language and utilized for simulating the classic problem of gamma ray beam incident on finite plane slabs of absorbing materials.The source geometry adopted in this program is plane normal source. Dose buildup factor of gamma photons in the absence and presence pair production effect have been calculated in the energy range (4-10) MeV for Aluminum and Lead up to 5 mean free path thickness.Dose buildup factor in the presence of pair production is higher than dose buildup factor in the absence of pair production effect.The deviation between the values of dose buildup factor in the presence and absence pair production is increased when the energy is increased within the studied energy range because the cross section for pair production is increased within the studied energy range

  11. Range and energy loss rate of 118 MeV 28Si in some polymers

    In the present work, range and energy loss rate of 28Si in four dielectric track detectors viz: Makrofol-KG (MFKG), Makrofol-G (MFG), Triafol-BN (TBN) and LR-115 (cellulose nitrate) have been measured. To calculate these parameters, a curve fitting method was proved to be very useful and easier with more accuracy. (author)

  12. Cross sections in the energy range from 10 to 40 MeV calculated with the GNASH code. [GNASA, below 40 MeV

    Arthur, E.D.; Young, P.G.

    1977-01-01

    A brief description of the preequilibrium-statistical model code GNASH is given. Features which make the code applicable to the calculation of cross sections induced by nucleons of energy 40 MeV or less are described. Finally, examples of calculations of neutron- and proton-induced reaction cross sections, activation cross sections, and secondary spectra made with global input parameters are given.

  13. Acceleration of atomic clusters in the MeV energy range by the 1 MV Tandetron accelerator

    Atomic clusters of Bn, Cn, Aln, Sin and Cun can be accelerated in the MeV energy range by using the 1 MV Tandetron accelerator at the University of Tsukuba. The negative cluster ions are generated by a Cesium sputtering ion source and extracted by the energy of 20 keV. The charge exchange from negative to positive cluster ion is achieved by collision with stripper gas in a gas cell at the high voltage terminal. It is necessary to accelerate cluster ions as the same energy ratio (MeV/atom) for the interaction experiment between cluster ions and the target. The terminal voltage of the 1 MV Tandetron accelerator is possible to be varied from 0.1 to 1.0 MV. We select the accelerating energy to 0.24 MeV/atom for small cluster ions (n ≤ 8). Experimental results obtained with accelerating Cn cluster ions are reported. (author)

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

    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.

  15. Activation cross sections of deuteron induced reactions on niobium in the 30-50 MeV energy range

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

    2016-04-01

    Activation cross-sections of deuterons induced reactions on Nb targets were determined with the aim of different applications and comparison with theoretical models. We present the experimental excitation functions of 93Nb(d,x)93m,90Mo, 92m,91m,90Nb, 89,88Zr and 88,87m,87gY in the energy range of 30-50 MeV. The results were compared with earlier measurements and with the cross-sections calculated by means of the theoretical model codes ALICE-D, EMPIRE-D and TALYS (on-line TENDL-2014 and TENDL-2015 libraries). Possible applications of the radioisotopes are discussed in detail.

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

    Sjue, S. K. L., E-mail: sjue@lanl.gov; Mariam, F. G.; Merrill, F. E.; Morris, C. L.; Saunders, A. [Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2016-01-15

    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.

  17. Stopping power of palladium for protons in the energy range 0.300-3.100 MeV

    Miranda, P. A.; Sepúlveda, A.; Morales, J. R.; Rodriguez, T.; Burgos, E.; Fernández, H.

    2014-01-01

    The stopping power of palladium for protons has been measured using the transmission method with an overall uncertainty of around 5% over the energy range Ep=(0.300-3.100) MeV. These stopping power data are then compared to stopping power values calculated by the SRIM-2010 code and to those derived from a model based on the dielectric formalism. Subsequently, and within the framework of the modified Bethe-Bloch theory, this stopping power data were used for extracting Pd target mean excitation and ionization potential, (I = 468 ± 5 eV), and Barkas effect parameter, (b = 1.51 ± 0.06). A good agreement is found between the obtained results and values reported in literature.

  18. Neutron-induced fission cross sections of 233U and 243Am in the energy range 0.5 Mev En 20 MeV @ n_TOF

    Belloni, F; Milazzo, P M; Calviani, M; Colonna, N; Mastinu, P; Abbondanno, U; Aerts, G; Álvarez, H; Álvarez-Velarde, F; Andriamonje, S; Andrzejewski, J; Assimakopoulos, P; Audouin, L; Badurek, G; Baumann, P; Becvár, F; Berthoumieux, E; Calviño, F; Cano-Ott, D; Capote, R; Carrapiço, C; Cennini, P; Chepel, V; Chiaveri, E; Cortes, G; Couture, A; Cox, J; Dahlfors, M; David, S; Dillmann, I; Domingo-Pardo, C; Dridi, W; Duran, I; Eleftheriadis, C; Embid-Segura, M; Ferrant, L; Ferrari, A; Ferreira-Marques, R; Fujii, K; Furman, W; Goncalves, I; González-Romero, E; Gramegna, F; Guerrero, C; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martinez, A; Igashira, M; Jericha, E; Käppeler, F; Kadi, Y; Karadimos, D; Karamanis, D; Kerveno, M; Koehler, P; Kossionides, E; Krticka, M; Lampoudis, C; Leeb, H; Lindote, A; Lopes, I; Lozano, M; Lukic, S; Marganiec, J; Marrone, S; Martínez, T; Massimi, C; Mengoni, A; Moreau, C; Mosconi, M; Neves, F; Oberhummer, H; O'Brien, S; Pancin, J; Papachristodoulou, C; Papadopoulos, C; Paradela, C; Patronis, N; Pavlik, A; Pavlopoulos, P; Perrot, L; Pigni, M T; Plag, R; Plompen, A; Plukis, A; Poch, A; Praena, J; Pretel, C; Quesada, J; Rauscher, T; Reifarth, R; Rubbia, C; Rudolf, G; Rullhusen, P; Salgado, J; Santos, C; Sarchiapone, L; Savvidis, I; Stephan, C; Tagliente, G; Tain, J L; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vazl, P; Ventura, A; Villamarin, D; Vincente, M C; Vlachoudis, V; Vlastou, R; Voss, F; Walter, S; Wiescher, M; Wisshak, K

    2011-01-01

    Neutron-induced fission cross-sections of actinides have been recently measured at the neutron time of flight facility n_TOF at CERN in the frame of a research project involving isotopes relevant for nuclear astrophysics and nuclear technologies. Fission fragments are detected by a gas counter with good discrimination between nuclear fission products and background events. Neutron-induced fission cross-sections of 233U and 243Am were determined relative to 235U. The present paper reports the results obtained at neutron energies between 0.5 and 20 MeV.

  19. Stopping power of palladium for protons in the energy range 0.300–3.100 MeV

    Miranda, P.A., E-mail: pjmirand@gmail.com; Sepúlveda, A.; Morales, J.R.; Rodriguez, T.; Burgos, E.; Fernández, H.

    2014-01-01

    The stopping power of palladium for protons has been measured using the transmission method with an overall uncertainty of around 5% over the energy range E{sub p}=(0.300–3.100) MeV. These stopping power data are then compared to stopping power values calculated by the SRIM-2010 code and to those derived from a model based on the dielectric formalism. Subsequently, and within the framework of the modified Bethe–Bloch theory, this stopping power data were used for extracting Pd target mean excitation and ionization potential, (I = 468 ± 5 eV), and Barkas effect parameter, (b = 1.51 ± 0.06). A good agreement is found between the obtained results and values reported in literature. It is worth mentioning that these are the first reported results for protons on palladium over this energy range, which is often used in IBA applications, such as Rutherford Backscattering Spectrometry (RBS) and Proton Induced X-ray Emission (PIXE)

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

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

    2016-01-01

    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 40 MeV up to 50 MeV. 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 37-50 MeV 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 TALYS1.6 nuclear model code as listed in the on-line library TENDL-2014.

  1. Proton Inelastic Mean Free Path in a Group of Organic Materials in 0.05-10 MeV Range

    TAN Zhen-Yu; XIA Yue-Yuan; ZHAO Ming-Wen; LIU Xiang-Dong

    2010-01-01

    @@ Inelastic mean free paths (MFPs) of 0.05-10 MeV protons in a group of 10 organic compounds are systematically calculated.The calculations are based on the method newly derived from the Ashley optical-data model and from the higher-order correction terms in stopping power calculations.Especially,in this method the new and empirical Bloch correction for the inelastic MFP is given.An evaluation for the optical energy loss function is incorporated into the present calculatious because of the lack of available experimental optical data for the considered organic compounds expect for kapton.The proton inelastic MFPs for these 10 organic compounds in the energy range from 0.05 to 10 Me V are presented here for the first time,and the combination of these inelastic MFP data and our previous data of stopping power calculation for these bioorganic compounds may form a useful database for Monte Carlo track-structure studies of various radiation effects on these materials.

  2. Finite range distorted wave analysis of 101.3 MeV 16O(p, pd)14N* reaction

    Experimental and theoretical studies of cluster knockout reactions have been progressing for the past several decades. This is to study the cluster structure as well as to yield the cluster spectroscopic factor in the light-medium mass nuclei using quasi-free (p, pα), (α, 2α), (p, pd), (α, αd) type of reactions. The spectroscopic factors deduced from the (α, 2α) reactions are found be almost 100 times larger than expected from the conventional shell model estimates. These values were deduced by comparing the experimental data with the predictions of the conventional Zero Range-Distorted Wave Impulse Approximation (ZR-DWIA) calculations. Analysis using the FR-DWIA formalism has been performed for the 101.3 MeV 16O(p, pd)14N* quasi-free reaction using all-through attractive (A) and an L-dependent attractive plus repulsive core (A+R) (of 2.5 fm) between the p and d potential

  3. Neutron spectra in the energy range from 10-8 to hundreds of MeV measurement in hard scattered radiation fields

    The technique of neutron spectra unfolding in wide energy range from 10-8 to hundreds of MeV on the base of multisphere Bonner's detector and plastic scintillator spectrometer ridings has been described. This technique is intended for neutron spectra measurements in fields of mixed scattered radiation behind accelerators shielding and neutron component of cosmic background. The expressions of neutron maximum equivalent and ambient doses in wide energy range and neutron fluences of energy above 20 MeV are presented. 13 refs.; 5 figs

  4. Application of pulsed neutron technique for integral neutron cross-section tests in the MeV range

    The spectra of neutrons scattered by several elements and compounds for an incident beam of 14 MeV neutrons have been studied by the time of flight method at Livermore in the so called 'Livermore Pulsed Sphere Program'. The measurements have been compared with results of Monte Carlo and neutron transport codes to provide checks on the input cross-sections. Similar measurements have been carried out at Oak ridge for incident neutron energies between 1 MeV to 20 MeV with a view to obtain information useful for neutron shielding calculations. The salient features of these measurements and proposals for an experimental program for obtaining data of interest are reviewed. (author)

  5. Fission fragment mass, kinetic energy and angular distribution for 235U(n,f) in the neutron energy range from thermal to 6 MeV

    A double Frisch gridded ionization chamber has been used for the measurements. For both fission fragments the mass, kinetic energy and emission angle is found. Data have been measured at different neutron energies, Esub(n), ranging from thermal to 6.0 MeV in steps of 0.5 MeV. The measured angular anisotropies will be shown. A fit, based on statistical theory, to earlier measurements of negative anisotropies for Esub(n)<=0.2 MeV will be discussed.The measured total kinetic energy averaged over all fragment masses, TKE-bar(Esub(n)), shows a sudden decrease at Esub(n)approx. 4.5 MeV in agreement with earlier measurements. This sudden decrease can not be explained by the measured change in the mass distribution. The present data of TKE-bar(Esub(n)) as function of mass-split reveal that TKE-bar(Esub(n)) decreases with Esub(n) for mass splits around the 104/132 split as predicted by calculations of B.D. Wilkins et al. It is also seen that TKE-bar(Esub(n)) increases with Esub(n) for the symmetric and the extreme asymmetric fissions. The very structured mass distribution from approximately cold fragmentation will be presented. (author)

  6. An improved long counter for neutron fluence measurement with a flat response over a wide energy range from 1 keV to 15 MeV

    A new long counter has been developed with a flat energy response over a wide range from 1 keV to 15 MeV. It consists of five 3He proportional counter tubes and a number of carefully designed polyethylene moderators. The structure of this detector was determined by careful Monte Carlo simulations. The calculated results show that the efficiency of this counter is uniform from 1 keV neutron energy to 15 MeV. Calibration was performed on an Am–Be source and the accelerator-produced monoenergetic D–D and D–T neutron sources. Fluctuation of the response curve is less than 10% over this energy range

  7. Curves for the response of a Ge(Li) detector to gamma rays in the energy range up to 11 MeV

    Kopecký, J.; Ratyński, W.; Warming, Inge Elisabeth

    1967-01-01

    The response function of a Ge(Li) coaxial detector with a sensitive volume of 17 cm3 for gamma rays of energies ranging from 2.23 to 10.83 MeV has been determined. The measurements were carried out with an experimental set-up using the neutron beam from the DR 3 reactor ar Risö and the (n, γ...

  8. Calculation of SF6-/SF6 and Cl-/CFCl3 electron attachment cross sections in the energy range 0-100 meV

    Chutjian, A.

    1982-01-01

    Electron attachment cross sections for the processes SF6-/SF6 and Cl-/CFCl3 are calculated in a local theory using a model in which diatomic-like potential energy curves for the normal modes are constructed from available spectroscopic data. Thermally populated vibrational and rotational levels are included. Good agreement is found with experimental cross sections in the energy range 5-100 meV for a particular choice of potential energy curve parameters.

  9. Excitation functions of some neutron threshold reactions on 89Y in the energy range of 7.8 to 14.7 MeV

    Excitation functions were measured for 89Y(n,2n)88Y, 89Y(n,p)89Sr and 89Y(n,α)86Rb reactions from their respective thresholds up to 14.7 MeV using the activation technique. Quasi-monoenergetic neutrons in the energy range of 7.8 to 13.3 MeV were produced via the 2H(d,n)3He reaction on a D2 gas target at the Juelich compact cyclotron (CV 28), and monoenergetic neutrons in the range of 13.8 to 14.7 MeV using the D-T neutron generator at Debrecen. For characterization of 88Y and 86Rb, high-resolution γ-ray spectrometry was applied. The latter product was also separated radiochemically and characterized by low-level β- counting; the results obtained using the two counting methods were generally in good agreement. The product 89Sr is a pure β- emitter: its activity was exclusively assayed via radiochemical separation and β- counting. Our results agree with the literature values on the (n,2n) reaction and provide the first consistent set of data on the (n,p) and (n,α) reactions near their thresholds. Statistical model calculations incorporating precompound effects were performed on the three excitation functions under consideration. The experimental and theoretical results were found to be in good agreement. Some systematic trends in the excitation functions in this mass region are discussed. (orig.)

  10. Neutron Radiative Capture Cross Section of 232Th in the Energy Range from 0.06 to 2 MeV

    The neutron capture cross section of 232Th has been measured relative to σ(n, γ) for 197Au and σ(n,f) for 235U in the energy range from 60 keV to 2 MeV. Neutrons were produced by the 7Li(p,n) and T(p,n) reactions at the 4-MV Van de Graaff Accelerator of CEN Bordeaux-Gradignan. The activation technique was used, and the cross section was measured relative to the 197Au(n,γ) standard cross section up to 1 MeV. The characteristic gamma lines of the product nuclei 233Pa and 198Au were measured with a 40% high-purity germanium detector. Above this energy, the reaction 235U(n,f) was also used as a second standard, and the fission fragments were detected with a photovoltaic cell. The results, after applying the appropriate corrections, indicate that the cross sections are close to the JENDL-3 database values up to 800 keV and over 1.4 MeV. For energies in the intermediate range, our values are slightly lower than those from all the libraries

  11. Neutron radiative capture cross-section of 232Th in the energy range from 0.06 to 2 MeV

    Neutron capture cross-section of 232Th have been measured relative to σ(n,γ) for 197Au and σ(n,f) for 235U in the energy range from 60 keV to 2 MeV. Neutrons were produced by the 7Li(p,n) and T(p,n) reactions at the 4 MV Van de Graaff Accelerator of CEN/Bordeaux. The activation technique was used and the cross-section was measured relative to the 197Au(n,γ) standard cross-section up to 1 MeV. Above this energy, the reaction 235U(n,f) was also used as a second standard and the fission fragments were detected with a photovoltaic cell. The results after applying the appropriate corrections indicate that the cross-sections are close to the JENDL-3 database values up to 800 keV and over 1.4 MeV. For energies in the intermediate range, values are slightly lower to the ones from all the libraries. (author)

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

    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/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. 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.

  13. Forward-to-backward asymmetry of the (γ,n) reaction in the energy range 20-30 MeV

    The forward-to-backward asymmetry of neutrons emitted in the (γ,n) reactions on /sup nat/Pb and /sup nat/Cd targets was measured for photons in the range of 20 to 30 MeV, where the isovector quadrupole giant resonance is expected to lie. The asymmetry was observed to increase from small values (≅0.2) to large ones (≅0.6 and 0.8) for /sup nat/Cd and /sup nat/Pb, respectively. This phenomenon is interpreted as the interference between E1 and E2 amplitudes. From an analysis of the asymmetry the excitation energies of the E2 isovector resonances were estimated to be 23.5 +- 1.5 and 26.5 +- 1.5 MeV for the Pb and Cd nuclei, respectively. The E2 isovector resonances are found to be considerably wider than the E1 resonances. 36 refs., 15 figs., 4 tabs

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

    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.

  15. Violent collisions between Ar and Ag in the energy range 30-60 MeV per nucleon: persistence of deeply inelastic collisions and temperature limits

    The dynamics of violent collisions for the 40Ar + natAg system is studied between 27 and 57 MeV per nucleon. The dominance of binary dissipative collisions, accompanied by an increasing abundance of pre-equilibrium emission for central collisions, is demonstrated over the whole bombarding energy range studied. The experimentally observed correlation between the emission angle of the light partner and the damping of the relative motion yields information on the in-medium nucleon-nucleon section. Finally, for the most violent collisions, a saturation of the temperature for the heavy partner is observed at a value of about 7 MeV. At the same time, this saturation is also observed in the multiplicities for evaporated light charged particles. (authors)

  16. Proton inelastic mean free path in a group of bioorganic compounds and water in 0.05-10 MeV range - Including higher-order corrections

    Tan Zhenyu, E-mail: tzy@sdu.edu.c [School of Electrical Engineering, Shandong University, Jinan 250061, Shandong (China); Xia Yueyuan; Zhao Mingwen; Liu Xiangdong [School of Physics, Shandong University, Jinan 250100, Shandong (China)

    2010-07-15

    The systematic calculations of the inelastic mean free paths (MFP) of 0.05-10 MeV protons in a group of eleven important bioorganic compounds, i.e. DNA, five bases, three fatty acids, cellulose and {beta}-carotene, have been performed. The expressions for the calculations are derived from the Ashley's optical-data model and from the higher-order correction terms in stopping power calculations. Especially, the Bloch correction for the inelastic MFP is proposed empirically in this work. The inelastic MFPs for energetic protons in water are also evaluated and compared with other theoretical calculations. The proton inelastic MFPs for these 11 bioorganic compounds in the energy range from 0.05 to 10 MeV are presented here for the first time, and might be useful for studies of various radiation effects in these materials.

  17. Tables of range and stopping power of chemical elements for charged particles of energy 0.5 to 500 MeV

    The range, energy loss, and differential of rate of energy loss were tabulated for 5 incident particles or ions (proton, deuteron, triton, helium-3 and helium-4) and for 37 target materials (H, He, Li, Be, B, C, N, O, F, Ne, Na, Al, Si, Cl, Ca, V, Fe, Ni, Cu, Ge, Br, Y, Zr, Mo, Rh, Ag, Cd, Sn, I, Cs, Nd, Gd, Er, Ta, Au, Pb, U) The incident energy range covered is from 0.05 to 500 MeV. An erratum report is added: 74 pages from 223 to 296 of the initial report have to be replaced by the pages contained in the erratum report

  18. Evaluation of 242Pu data for the incident neutron energy range 0.1 - 6 MeV

    This report presents the models and the procedures used for the calculation of the quantities required by Files 3, 4 and 5 of ENDF-6 for 242Pu. These quantities are the integrated cross sections for the total, fission, scattering and gamma-capture reactions and the angular and energy distributions of the scattered neutrons for the incident neutron energies 0.01/6 MeV. The direct mechanism was treated with the coupled-channel method using a deformed optical potential defined by a set of actinide region parameters established by the authors. For the compound nucleus calculations, a new HRTW version of the statistical model extended to describe the fission at subbarrier energies was used. To describe the continuous part of the transition states spectrum, analytical expressions have been established. The energy distributions of the scattered neutrons have been calculated with an author's version of the Los Alamos model. The agreement of the calculations with the existing experimental data is good. (author)

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

    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

  20. The investigation of neutron cross section with the energy range from 1 to 50 MeV for some near-spherical nuclei

    In this paper, we calculated the total and reaction cross sections of elastic scattering and pickup reactions of neutron with incident energies from 1 to 50 MeV for four near-spherical nuclei, which the mass number range from 48 to 208. In our calculation, the optical model potential (OMP) and Born approximations are used to describe the direct interactions between neutron and these nuclei, parameters for OMP and properties of the nuclei are taken from RIPL-3. Our results are compared with experimental and evaluated data from TENDL. (author)

  1. Experimental SF6/-//SF6 and Cl/-//CFC13 electron-attachment cross sections in the energy range 0-200 meV

    Chutjian, A.

    1981-01-01

    Experimental cross sections for the electron-attachment processes for SF6(-)/SF6 and Cl(-)/CFl3 are reported in the energy range 0-200 meV by normalizing each attachment line shape to measurement of a thermal rate coefficient. When the same ion states are detected, good agreement is found between present values, for which a monoenergetic electron source is used, and swarm-unfolded results. The present data constitute a new limit for cross sections reported at high resolution at the lowest electron energy.

  2. Hauser-Feshbach calculations of neutron-induced reaction cross sections for 52Cr in 6-20 MeV neutron energy range

    Calculations of cross sections of neutron induced reactions for 52Cr in 6-20 MeV energy range have been performed using Hauser-Feshbach code developed by the author. The calculations include cross sections of (n,n'), (n.np), (n,2n), (n,p), (n,pn), (n,pγ), (n,α), (n,αγ) and (n, αn) reactions induced in 52Cr. The calculations have been compared with measurements and evaluations. (author). 30 refs, 11 figs, 2 tabs

  3. Measurement of secondary neutrons and gamma rays produced by neutron bombardment of water over the incident energy range 1 to 20 MeV

    The spectra of secondary neutrons and gamma rays produced by neutron bombardment of a thick (approx. 1 mean free path) sample of water have been measured as a function of the incident neutron energy over the range 1 to 20 MeV. Data were taken for angles of 900 and 1400. A linac (ORELA) was used as a neutron source with a 47-m flight path. Incident energy was determined by time-of-flight, while secondary spectra were determined by pulse-height unfolding techniques. The results of the measurements are presented in forms suitable for comparison to calculations based on the evaluated data files. (6 figures, 9 tables) (auth)

  4. To calculating the gamma radiation interaction coefficients by an interpolation method in the 0.02-2 MeV energy range

    Interpolation formula earlier used for determining linear coefficients of gamma radiation attenuation in a substance is applied for determining mass coefficients of attenuation without regard for coherent scattering and mass coefficients of interaction due to incoherent scattering on bound electrons as well as mass coefficients of energy absorption. It is concluded that approximation error for 0.02-2 MeV energy range doesn't exceed 1.5 % except for several points for which the difference constitutes 2.5-3 %

  5. Responses of conventional and extended-range neutron detectors in mixed radiation fields around a 150-MeV electron LINAC

    This study analyzed the responses of two types of neutron detector in mixed gamma-ray and neutron radiation fields around a 150-MeV electron linear accelerator (LINAC). The detectors were self-assembled, high efficiency, and designed in two configurations: (1) a conventional moderated-type neutron detector based on a large cylindrical He-3 proportional counter; and (2) an extended-range version with an embedded layer of lead in the moderator to increase the detector’s sensitivity to high-energy neutrons. Two sets of the detectors were used to measure neutrons at the downstream and lateral locations simultaneously, where the radiation fields differed considerably in intensities and spectra of gamma rays and neutrons. Analyzing the detector responses through a comparison between calculations and measurements indicated that not only neutrons but also high-energy gamma rays (>5 MeV) triggered the detectors because of photoneutrons produced in the detector materials. In the lateral direction, the contribution of photoneutrons to both detectors was negligible. Downstream of the LINAC, where high-energy photons were abundant, photoneutrons contributed approximately 6% of the response of the conventional neutron detector; however, almost 50% of the registered counts of the extended-range neutron detector were from photoneutrons because of the presence of the detector rather than the effect of the neutron field. Dose readings delivered by extended-range neutron detectors should be interpreted cautiously when used in radiation fields containing a mixture of neutrons and high-energy gamma rays

  6. Measurement of cross sections for the scattering of neutrons in the energy range from 2 MeV to 4 MeV with the {sup 15}N(p,n) reaction as neutron source; Messung von Wirkungsquerschnitten fuer die Streuung von Neutronen im Energiebereich von 2 MeV bis 4 MeV mit der {sup 15}N(p,n)-Reaktion als Neutronenquelle

    Poenitz, Erik

    2010-04-26

    In future nuclear facilities, the materials lead and bismuth can play a more important role than in today's nuclear reactors. Reliable cross section data are required for the design of those facilities. In particular the neutron transport in the lead spallation target of an Accelerator-Driven Subcritical Reactor strongly depends on the inelastic neutron scattering cross sections in the energy region from 0.5 MeV to 6 MeV. In the recent 20 years, elastic and inelastic neutron scattering cross sections were measured with high precision for a variety of elements at the PTB time-of-flight spectrometer. The D(d,n) reaction was primarily used for the production of neutrons. Because of the Q value of the reaction and the available deuteron energies, neutrons in the energy range from 6 MeV to 16 MeV can be produced. For the cross section measurement at lower energies, however, another neutron producing reaction is required. The {sup 15}N(p,n){sup 15}O reaction was chosen, as it allows the production of monoenergetic neutrons with up to 5.7MeV energy. In this work, the {sup 15}N(p,n) reaction was studied with focus on the suitability as a source for monoenergetic neutrons in scattering experiments. This includes the measurement of differential cross sections for the neutron producing reaction and the choice of optimum target conditions. Differential elastic and inelastic neutron scattering cross sections were measured for lead at four energies in the region from 2 MeV to 4 MeV incident neutron energy using the time-of-flight technique. A lead sample with natural isotopic composition was used. NE213 liquid scintillation detectors with well-known detection efficiencies were used for the detection of the scattered neutrons. Angle-integrated cross sections were determined by a Legendre polynomial expansion using least-squares methods. Additionally, measurements were carried out for isotopically pure {sup 209}Bi and {sup 181}Ta samples at 4 MeV incident neutron energy

  7. Efficiency calibration of scintillation detectors in the neutron energy range 1.5-25 MeV by the associated particle technique

    The associated particle technique, with a gas target, has been used to measure the absolute central neutron detection efficiency of two scintillators, (NE213 and NE102A) with an uncertainty of less than +- 2%, over the energy range 1.5-25 MeV. A commercial n/γ discrimination system was used with NE213. Efficiencies for various discrimination levels were determined simultaneously by two parameter computer storage. The average efficiency of each detector was measured by scanning the neutron cone across the front face. The measurements have been compared with two Monte Carlo efficiency programs (Stanton's and 05S), without artificially fitting any parameters. When the discrimination level (in terms of proton energy) is determined from the measured light output relationship, very good agreement (to about 3%) is obtained between the measurements and the predictions. The agreement of a simple analytical expression is also found to be good over the energy range where n-p scattering dominates. (orig.)

  8. Performance of Geant4 in simulating semiconductor particle detector response in the energy range below 1 MeV

    Geant4 simulations play a crucial role in the analysis and interpretation of experiments providing low energy precision tests of the Standard Model. This paper focuses on the accuracy of the description of the electron processes in the energy range between 100 and 1000 keV. The effect of the different simulation parameters and multiple scattering models on the backscattering coefficients is investigated. Simulations of the response of HPGe and passivated implanted planar Si detectors to β particles are compared to experimental results. An overall good agreement is found between Geant4 simulations and experimental data

  9. Calculated neutron-activation cross sections for E/sub n/ /le/ 100 MeV for a range of accelerator materials

    Activation problems associated with particle accelerators are commonly dominated by reactions of secondary neutrons produced in reactions of beam particles with accelerator or beam stop materials. Measured values of neutron-activation cross sections above a few MeV are sparse. Calculations with the GNASH code have been made for neutrons incident on all stable nuclides of a range of elements common to accelerator materials. These elements include B, C, N, O, Ne, Mg, Al, Si, P, S, Ar, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, Nd, and Sm. Calculations were made for a grid of incident neutron energies extending to 100 MeV. Cross sections leading to the direct production of as many as 87 activation products for each of 84 target nuclide were tabulated on this grid of neutron energies, each beginning with the threshold for the product nuclide's formation. Multigrouped values of these cross sections have been calculated and are being integrated into the cross-section library of the REAC-2 neutron activation code. Illustrative cross sections are presented. 20 refs., 6 figs., 1 tab

  10. Proton Inelastic Mean Free Path in a Group of Organic Materials in 0.05–10 MeV Range

    Inelastic mean free paths (MFPs) of 0.05–10 MeV protons in a group of 10 organic compounds are systematically calculated. The calculations are based on the method newly derived from the Ashley optical-data model and from the higher-order correction terms in stopping power calculations. Especially, in this method the new and empirical Bloch correction for the inelastic MFP is given. An evaluation for the optical energy loss function is incorporated into the present calculations because of the lack of available experimental optical data for the considered organic compounds expect for kapton. The proton inelastic MFPs for these 10 organic compounds in the energy range from 0.05 to 10 MeV are presented here for the first time, and the combination of these inelastic MFP data and our previous data of stopping power calculation for these bioorganic compounds may form a useful database for Monte Carlo track-structure studies of various radiation effects on these materials. (atomic and molecular physics)

  11. Differential cross section measurement of the elastic neutron-deuteron-scattering in the energy range 2.5-30 MeV

    The differential cross-section of the elastic D(n, n)D scattering has been measured in the energy range 2.5-30 MeV. A pulsed 'white' neutron beam from deuterons (Esub(d) approx. equal to 48 MeV) on natural uranium was collimated by bulk metal shielding in a approx. equal to 60 m long vacuum tube in the THETAsub(LAB) = O0-direction. The collimated neutrons were scattered from a partially and a totally deuterated scintillator. The mixed scatterer of hydrogen, deuterium and carbon provided the absolute calibration of the (n, d)-cross-section by the well-known (n, p)-cross-section. The scattered neutrons were detected by two detectors at 14 laboratory angles. Five parameters for each event were measured in coincidence, so that background reduction could be done. Additional contributions from multiple-scattering were determined by Monte-Carlo calculations. Twenty angular distributions were obtained with uncertainties between 2 and 6%. Some significant deviations from older measurements and from exact 3-body-calculations were found. Much importance was attached to the determination of the properties of the neutron-detectors, especially of the so-called 'black-detector'. (orig.)

  12. Forward recoil range distribution (FRRD) measurements in 16O + 156Gd system at ∼ 72, 82 and 93 MeV energies

    Incomplete fusion (ICF) reaction dynamics has been a subject of increasing interest in the last two decades. It has been observed that above the Coulomb barrier ICF process is the dominant one. In the ICF reaction mechanism, a part of the projectile fuses with target nucleus and remaining part of the projectile (projectile like fragments) moves in the forward direction as a spectator, which lead to transfer of partial linear momentum from the projectile to the target nucleus. The main objective of the present work is the measurement of forward recoil range distributions (RRDs) to understand the degree of linear momentum transfer from projectile 16O to target 156Gd, at different projectile energies, E ∼ 72, 82 and 93 MeV

  13. Elastic recoil cross section determination of deuterium by helium-4 ions at 30° with the energy range of 2.6-7.4 MeV

    Han, Zhibin; Hao, Wanli; Wang, Chunjie; Shi, Liqun

    2016-05-01

    The elastic recoil cross section for D(4He, D) 4He was determined at a recoil angle of 30° over an incident helium energy range from 2.6 to 7.4 MeV. A thin solid target Ta/TiDx/Si used for cross section measurement was prepared by direct current magnetron sputtering, and it was so stable to ion beam bombardment that nearly no deuterium loss (less than 0.2%) exists over the whole experiment. A relative determination method is adopted in this measurement. It can avoid the error from the beam dose and the solid angle of the detectors and it is also free to direct measurement of D content in the film. The total uncertainty in the cross section determination is less than 5%.

  14. Measurement of (n,2n) reaction cross-sections on isotopes of zinc, germanium and scandium in neutron energy range 13.82-14.7 MeV

    The cross-sections for the reactions 64Zn(n,2n)63Zn, 76Ge (n,2n)75m+gGe and 45Sc(n,2n)44mSc were measured in the energy range 13.82-14.71 MeV. The activation technique was used in combination with high resolution HPGe detector gamma-ray spectroscopy. Neutrons were produced via D-T reaction at J-25 neutron generator of the Institute of Nuclear Science and Technology, AERE, Dhaka, Bangladesh. The neutron flux at each energy was determined using monitor reaction 27Al(n, α)24Na. The nuclear model calculations using the computer codes SINCROS-II and EXIFON were undertaken to describe the excitation functions of the investigated reactions. (author)

  15. A fully microscopic model analysis of the elastic and inelastic scattering of protons from 12C and for energies in the range 200 to 800 MeV

    Medium modified effective two nucleon interactions are defined for protons incident upon 12C with energies in the range 200 to 800 MeV. Those effective interactions have been folded with the ground state density to specify nonlocal optical potentials that were then used to analyse the elastic scattering differential cross sections and analysing powers. A select set of isoscalar and isovector, positive and negative parity, inelastic proton scattering transitions have also been analysed using the same (microscopic) optical models to define the distorted wave functions needed in Distorted Wave Approximation calculations of the associated differential cross sections and analysing powers. All results are compared with ones found using the Love-Franey effective interactions. The nuclear structure relating to these transitions was chosen from (0+2) ℎω and (1+3)ℎω shell model calculations of the positive and negative parity spectra of 12C respectively. 21 refs., 12 figs

  16. Energy dependence of some neutron detector sensitivity in the energy range from 17 keV up to 1 MeV

    The results of experimental determination of sensitivity of neutron detectors used as dosimeters in the energy range from 17 keV to 1 MeV are presented. The measurements were performed in the EhG-2.5 accelerator. Monoenergetic neutrons were produced in the T (p, n)3He reaction at different proton energies. The detectors were placed at angles from 30 deg to 120 deg to proton beam direction. The detector sensitivity was evaluated by comparison of their values with those of the OVC-3M standard neutron counter. The obtained results could be used for determining energy dependences of sensitivities of detectors under study and for evaluating the errors of measurements of neutron doses in the radiation fields behind nuclear-physical installation shielding

  17. Observations of diffuse cosmic gamma radiation in the 100-700 MeV energy range on the ''Kosmos-731'' satellite

    Using the ''Cosmos-731'' satellite with a gamma telescope and an acoustic spark chamber diffusive cosmic γ radiation in the 100-700 MeV range is investigated. The γ radiation intensity which is 2.5+-0.6x10-5 quanta x cm-2 x s-1 x sr-1 is determined. The dependence of the diffusive γ radiation intensity on the galaxial latitude is given. The γ quanta distribution in the Galaxy is homogeneous along the galaxial latitude. According to the least square method the index of integral exponential spectrum is found to be k-1=0.9+-0.3. In the total Galaxy region no local γ radiation sources with the flux exceeding 10-5 quantaxcm-2xs-1 is observed

  18. Response function of a superheated drop neutron monitor with lead shell in the thermal to 400-MeV energy range.

    Itoga, Toshiro; Asano, Yoshihiro; Tanimura, Yoshihiko

    2011-07-01

    Superheated drop detectors are currently used for personal and environmental dosimetry and their characteristics such as response to neutrons and temperature dependency are well known. A new bubble counter based on the superheated drop technology has been developed by Framework Scientific. However, the response of this detector with the lead shell is not clear especially above several tens of MeV. In this study, the response has been measured with quasi-monoenergetic and monoenergetic neutron sources with and without a lead shell. The experimental results were compared with the results of the Monte Carlo calculations using the 'Event Generator Mode' in the PHITS code with the JENDL-HE/2007 data library to clarify the response of this detector with a lead shell in the entire energy range. PMID:21493607

  19. Measurements of double differential charged particle emission cross sections and development of a wide range charged particles spectrometer for ten`s MeV neutrons

    Nauchi, Yasushi; Baba, Mamoru; Kiyosumi, Takehide [Tohoku Univ., Sendai (Japan). Faculty of Engineering] [and others

    1997-03-01

    We measured (n,xp), (n,xd) cross sections of C and Al for En=64.3 MeV neutrons at the {sup 7}Li(p,n) neutron sources facility at TIARA (Takasaki Establishment, JAERI) by using a conventional SSD-NaI telescope placed in the air. They show characteristic energy and angular dependence in high energy regions. In order to extend the measurements to low energy protons and {alpha} particles, a new spectrometer consisting of low pressure gas counters and BaF{sub 2} scintillators is now under development. A low threshold for low energy {alpha} particles will be achieved by using the gas counters. The particle identification over a wide energy range will be achieved by combining the {Delta}E-E method for low energy particles with the pulse shape discrimination (PSD) method of BaF{sub 2} for high energy particles. (author)

  20. Contributions to the study of fast neutron spectrum in the 10 keV - 3 MeV range

    The main objective of the work presented in this thesis was to create a fast neutron spectrum corresponding to the conditions required for a reference neutron field. The reference system for the fast neutron dosimetry in reactors, which the author promoted, is referred to as ΣΣ-ITN in the books. The conditions for introducing the ΣΣ systems into the thermal columns have been determined. The original contribution consists in determining the Westcott parameters of reactions 151Eu(n,γ) 152Eu and 176Lu(n,γ) 17+H7Lu used as thermal spectrum factors. The neutron description of the spectrum in cavity ΣΣ revealed that it is a Maxwell thermal spectrum displaying a temperature of 305+-7 deg C and a very small epithermal component (phisub(epi)/phisub(thermal) =4,5.10-4). Better methods for determining reaction absolute rates resulted in less errors in calculating the microscopic integral sections mediated on the ΣΣ spectrum; there are under 5% errors for the fission cross sections and between 3% and 8% errors for the activating ones. The section values determined by the author have been included into the EXFOR library (IAEA); they are considered as reference measuremtns for the nuclear data improvement program. Testing the proposed method for the TRIGA on the ΣΣ-INT system proved that the multiple foil method provides correct results for both describing the spectral shape and for obtaining absolute values of the flux. Taking into account that the ΣΣ-ITN spectrum is a rapid one, the proposed method could not be tested within the low energy thermal and epithermal domain. For testing the method on an operational reactor, the core of the VVR-S IFIN reactor was employed. Due to the spectral structure of this reactor, it was possible to test the procedure within the whole energy range. In this view, the 5/10 core channel was selected which is similar to the channel required for measurements in the TRIGA-ROMANIA reactor. The absolute spectrum values are given in a

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

    Amgarou, K. [Grup de Recerca en Radiacions Ionitzants, Departament de Fisica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Bedogni, R., E-mail: roberto.bedogni@lnf.infn.it [INFN-Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Via E. Fermi n. 40, 00044 Frascati (Italy); Domingo, C. [Grup de Recerca en Radiacions Ionitzants, Departament de Fisica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Esposito, A.; Gentile, A.; Carinci, G. [INFN-Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Via E. Fermi n. 40, 00044 Frascati (Italy); Russo, S. [INFN-Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 44, 95123 Catania (Italy)

    2011-10-21

    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{sup o} and 90{sup o} with respect to the beam-line. Here the ERBSS of UAB (Universidad Autonoma de Barcelona-Grup de Fisica 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

  2. Design Concept of a Seal-off Type 14 MeV Neutron Generator of 10''1''1n/s Range

    In, S. R.; Oh, B. H. [KAERI, Daejeon (Korea, Republic of)

    2015-05-15

    The total neutron fluence during the life time is expected to be around 10MW·yr/m''2 which may cause a damage of -100 dpa in materials. To estimate the adaptability of candidate materials in a few years, a 14MeV neutron source with a flux level of 3 - 5 x 10''1''8 n/s·m''2, which is the goal of the IFMIF facility costing more than ¤1000M, is necessitated. The problem in making an intense neutron generator of beam target type is really not on the neutron production rate, but on the huge heat generated in the target, because the fusion power is only one of thousands of beam power exerted on the target. We have a plan to develop neutron generators step by step from a 10''8 n/s level. The final goal is establishing a 14MeV neutron irradiation facility at 10''1''4 intensity level.. Up to the 10''1''0 n/s level, there occurs basically no critical thermal problem, because beam power density is in the range of tens W/cm''2. The neutron generator designed in a sealed-off type because of tritium safety is mainly composed of an ion source, target, reaction chamber, and getter pump.. The major design concepts for the neutron generator with the neutron production rate of 10''1''1 n/s range were presented. The specifications of the ion source, target and getter have been determined for attaining the goal of the neutron generation rate.

  3. The measurement of neutron differential scattering cross sections for 12C, 14N and 16O in the energy range 20-26 Mev

    The Ohio University Beam Swinger provides a high resolution, low back-ground time-of-flight facility for the measurement of elastic and inelastic neutron scattering. It has been used to obtain a comprehensive set of differential scattering cross sections for 12C, 14N, 16O and 40Ca between 18 and 26 MeV. The elastic cross sections can be used directly to obtain partial kerma factors and, combined with the known total cross sections, provide accurate values for the reaction cross sections. Angular distributions have been measured for inelastic scattering from all the nuclear levels that cannot decay by particle emission thus providing (by subtraction) a limit on the sum of all charged-particle producing reactions. The integrated cross sections for inelastic scattering from some particle-unstable states in 12C are in excellent agreement with the cross sections for three-body breakup obtained by Antolkovic et al. The differential data have been used, together with higher energy proton scattering data to produce energy-dependent optical model parameters for each of these nuclei in the energy range 20-60 MeV. It has been found that the elastic differential cross sections at theta > 1000 for 12C, 14N and 16O cannot be well described by a spherical optical model. Explicit consideration of coupled-channel effects, and in the case of 12C, deformation of the ground state, improves the agreement between calculation and experiment. Heavy ion recoil kerma factors and reaction cross sections have been obtained for each element and compared with previous calculations and measurements

  4. Measurement of proton polarization in the deuteron photodisintegration reaction on the linearly polarized photon beam in the energy range Eγ=290-420 MeV at angle Θpx=65 deg cms

    The results of measurement of proton polarization in the reaction plane (Pxz) and in the plane (Py) perpendicular to it, in the deuteron photodisintegration reaction in the photon energy range from 290 MeV to 420 MeV at proton escape angle in cms Θpx=65 deg, are presented. The results are compared with the predictions of theoretical calculations of the gradient-invariant model with account of dibaryon resonances. 6 refs.; 2 figs.; 1 tab

  5. Electron-transfer reactions of fast Xe/sup n/+ ions with Xe in the energy range 15 keV to 1.6 MeV

    Electron-transfer cross sections for the reactions of Xe/sup n/+ (n = 1--4) with Xe atoms have been determined as a function of projectile-ion kinetic energy in the range 15 keV--1.6 MeV. For Xe/sup n/+ (n = 2, 3, 4), cross sections for sequential transfer of two or more electrons in single-ion--atom collisions have been obtained. These cross sections decrease with increasing number of electrons transferred. The observed insensitivity of cross sections to projectile kinetic energy in the range investigated follows the condition that the linear velocity of the ion is less than the orbital velocity of a valence electron in the slow-moving target atom. Attenuation cross sections for reactions of Xe/sup n/+ (n = 2, 3, 4) follow approximately a Z2/sub direct-sum/ charge dependence. A simple classical model based on Coulomb forces yields cross sections with a reasonable fit to the experimental data

  6. Ion emission in solids bombarded with Aun+ (n = 1 - 9) clusters accelerated within the 0.15 - 1.25 MeV energy range

    This experimental work is devoted to the study of the ion emission in solids at the impact of gold clusters of energies within 0.15 to 1.25 MeV range. The physics of ion-solid collisions and the theoretical models of sputtering of solids under ion bombardment are presented in the first chapter. The chapter no. 2 deals with the description of the experimental setup. The study of a gold target allowed to evidence the role of the size and energy of the clusters in determining the emission intensity and the mass distribution of the ions. The 4. chapter gives results from the study of cesium iodide in which the intense emission of CsI clusters could be investigated quantitatively due to multiplicity measurements. Finally, the chapter no. 5 was devoted to the study of a biologic molecule, the phenylalanine, and of a pesticide molecule, chlorosulfuron. This work evidenced the importance of clusters for surface analyses by mass spectrometry

  7. High-resolution integrated germanium Compton polarimeter for the γ-ray energy range 80 keV-1 MeV

    Sareen, R. A.; Urban, W.; Barnett, A. R.; Varley, B. J.

    1995-06-01

    Parameters which govern the choice of a detection system to measure the linear polarization of γ rays at low energies are discussed. An integrated polarimeter is described which is constructed from a single crystal of germanium. It is a compact planar device with the sectors defined electrically, and which gives an energy resolution in the add-back mode of 1 keV at 300 keV. Its performance is demonstrated in a series of calibration measurements using both unpolarized radiation from radioactive sources and polarized γ rays from the 168Er(α,2n)170Yb reaction at Eα=25 MeV. Polarization measurements at energies as low as 84 keV have been achieved, where the sensitivity was 0.32±0.09. The sensitivity, efficiency, and energy resolution are reported. Our results indicate that energy resolution should be included in the definition of the figure of merit and we relate the new definition to earlier work. The comparisons show the advantages of the present design in the energy range below 300 keV and its competitiveness up to 1500 keV.

  8. High-resolution integrated germanium Compton polarimeter for the γ-ray energy range 80 keV--1 MeV

    Parameters which govern the choice of a detection system to measure the linear polarization of γ rays at low energies are discussed. An integrated polarimeter is described which is constructed from a single crystal of germanium. It is a compact planar device with the sectors defined electrically, and which gives an energy resolution in the add-back mode of 1 keV at 300 keV. Its performance is demonstrated in a series of calibration measurements using both unpolarized radiation from radioactive sources and polarized γ rays from the 168Er(α,2n)170Yb reaction at Eα=25 MeV. Polarization measurements at energies as low as 84 keV have been achieved, where the sensitivity was 0.32±0.09. The sensitivity, efficiency, and energy resolution are reported. Our results indicate that energy resolution should be included in the definition of the figure of merit and we relate the new definition to earlier work. The comparisons show the advantages of the present design in the energy range below 300 keV and its competitiveness up to 1500 keV. copyright 1995 American Institute of Physics

  9. Application of PWO crystals for detection of low-activity gamma- radiation in the energy range above 3 MeV

    Drobychev, G Yu; Fedorov, A A; Khruschinsky, A A; Korjik, M V; Lecoq, P; Missevitch, O V

    2005-01-01

    Lead tungstate PbWO4 (PWO) scintillator was developed during the R&D project initiated in a frame of preparation of experiments in high- energy physics to be carried out at new generation of colliders like LHC (CERN, Geneva, Switzerland). Compared to other promising fast and dense scintillators, PWO is an optimal compromise to make a very compact detector with good performance and the best price/performance ratio. Moreover, the results of PWO development carried out by the INP team together with collaborators show that scintillation parameters of PWO crystals can be further modified, which significantly extends opportunities of PWO application. One such field where an application of PWO scintillator can be very advantageous is a detection of low-activity gamma-radiation in the energy range above 3 MeV. Application of heavy scintillator allows to decrease a detector volume and therefore to reduce background. According to our preliminary estimations, PWO scintillation crystal will allow to reach significant...

  10. Excitation function of 59 Co (n, 2n) 58 Co process in the energy range 13.9-14.7 MeV

    The objective of the study is to measure the neutron cross sections for the 59 Co (n, 2n) 58 Co reaction around the 14 MeV energy region. Neutron activation cross section for almost all the nuclei, mostly in the medium energy region e.g., 7 to 20 MeV are reported in literature. Neutron cross section data around 14 MeV is of immense importance for the design of D + T fusion reactors. The accuracy of the cross section data at this energy region is a requirement for correct prediction of reactor parameters e.g., tritium breeding, nuclear heating, induced activity, etc. In order to perform the experiment, the Co-sample sandwiched in Ni foils was irradiated employing the J-25 Neutron Generator at the AERE, Savar, Dhaka. After irradiation, the counting was done by the activation technique using a high resolution Hp Ge gamma ray spectrometer. The gamma ray spectra was analyzed in a Canberra series-40 Multi-channel Analyzer. Calculations for cross sections were done at four different energies e.g., 13.870 MeV, 14.09 MeV, 14.483 MeV and 14.656 MeV. It was observed that the cross section data of the present work agrees well with JENDL-2 and other theoretical data. However, the ENDF/B-Vχ data is higher than the present values by about 11.60 to 14.27%. 1 fig., 17 refs., 2 tables (author)

  11. Secondary electron emission of thin carbon foils under the impact of hydrogen atoms, ions and molecular ions, under energies within the MeV range

    This work focuses on the study of the emission statistics of secondary electrons from thin carbon foils bombarded with H0, H2+ and H3+ projectiles in the 0.25-2.2 MeV energy range. The phenomenon of secondary electron emission from solids under the impact of swift ions is mainly due to inelastic interactions with target electrons. The phenomenological and theoretical descriptions, as well as a summary of the main theoretical models are the subject of the first chapter. The experimental set-up used to measure event by event the electron emission of the two faces of a thin carbon foil traversed by an energetic projectile is described in the chapter two. In this chapter are also presented the method and algorithms used to process experimental spectra in order to obtain the statistical distribution of the emitted electrons. Chapter three presents the measurements of secondary electron emission induced by H atoms passing through thin carbon foils. The secondary electron yields are studied in correlation with the emergent projectile charge state. We show the peculiar role of the projectile electron, whether it remains or not bound to the incident proton. The fourth chapter is dedicated to the secondary electron emission induced by H2+ and H3+ polyatomic ions. The results are interpreted in terms of collective effects in the interactions of these ions with solids. The role of the proximity of the protons, molecular ion fragments, upon the amplitude of these collective effects is evidenced from the study of the statistics of forward emission. These experiences allowed us to shed light on various aspects of atom and polyatomic ion inter-actions with solid surfaces. (author)

  12. Measurements of Neutron-Induced Fission Cross Sections of 205Tl, 204, 206, 207, 208Pb, and 209Bi using Quasi-Monoenergetic Neutrons in the Energy Range 35 - 174 MeV

    Tutin, Gennady A.; Ryzhov, Igor V.; Eismont, Vilen P.; Mitryukhin, Andrey G.; Oplavin, Valery S.; Soloviev, Sergey M.; Blomgren, Jan; Condè, Henri; Olsson, Nils; Renberg, Per-Ulf

    2005-05-01

    Cross sections for neutron-induced fission of 205Tl, 204, 206, 207, 208Pb, and 209Bi were measured in the energy range from 35 MeV to 174 MeV. The experiments were done at the neutron beam facility of The Svedberg Laboratory, using a multi-section Frisch-gridded ionization chamber for detection of the fission fragments. The neutron-induced fission cross section of 238U was employed as a reference. The results of the measurements are compared with existing experimental data.

  13. Measurements of the Fe-54 (n,p) Mn-54 Reaction Cross Section in the Neutron Energy Range 2.3-3.8 MeV

    We have measured the 54Fe (n, p) 54Mn reaction cross section using a surface barrier detector to record the number of protons released in the reaction. The neutron flux was determined by means of a hydrogenous radiator, detecting the scattered protons with the solid state detector, and calculating the number of impinging neutrons from the well known n-p scattering cross section. The 54Fe (n, p) 54Mn reaction cross section is found to increase from 25 mb at 2.3 MeV to 208 mb at 3.5 MeV

  14. Measure of elastic differential cross sections 3He (π±,π±) 3He and 4He (π±,π±) 4He in the 25 to 65 MeV range

    Measurement of low energy pion elastic differential cross sections on light nuclei 3He and 4He has been made to improve our understanding of pion-nucleus interaction mechanisms. For this purpose, π+ and π- cross sections at 25 and 51 MeV on 4He and 30, 45 and 65 MeV on 3He have been measured for scattering angles between 40 and 140 deg. in the laboratory. The pion flux was known within 2 pc accuracy and low temperature liquid targets were used. The scattered π+ and π- were detected in range spectrometers with 90 pc efficiency and 2 MeV energy resolution. Overall accuracy on the cross section is 5 pc. Comparison with microscopic optical potential calculations shows that much remains to be done to reproduced the measured cross sections. More particularly, Coulomb corrections, binding energy effects of the scattering nucleon and pion absorption should be more realistic to account properly for the data. (author)

  15. Excitation functions of proton-induced reactions on natural Nd and production of radionuclides relevant for double beta decay: Completing measurement in 5–35 MeV energy range

    Lebeda, O., E-mail: lebeda@ujf.cas.cz [Nuclear Physics Institute AS CR, v.v.i., Husinec-Řež 130, 250 68 Řež (Czech Republic); Lozza, V.; Petzoldt, J. [Institut für Kern und Teilchenphysik, Technische Universität Dresden, Zellescher Weg 19, 01069 Dresden (Germany); Štursa, J.; Zdychová, V. [Nuclear Physics Institute AS CR, v.v.i., Husinec-Řež 130, 250 68 Řež (Czech Republic); Zuber, K. [Institut für Kern und Teilchenphysik, Technische Universität Dresden, Zellescher Weg 19, 01069 Dresden (Germany)

    2014-09-15

    Cross-sections for the proton-induced reactions on natural neodymium in energy regions 5–10 MeV and 30–35 MeV were measured using the cyclotron U-120M at the Nuclear Physics Institute at Řež near Prague. This measurement completes the investigation previously done in the 10–30 MeV energy range. Results revealed practical production thresholds and secondary maxima and minima in the excitation functions. It allowed for more appropriate calculation of thick target yields and production rates of many longer-lived radionuclides potentially disturbing the search for neutrinoless double beta decay. Measured cross-sections are consistent with our previously published data.

  16. Excitation functions of proton-induced reactions on natural Nd and production of radionuclides relevant for double beta decay: Completing measurement in 5-35 MeV energy range

    Lebeda, O; Petzoldt, J; Stursa, J; Zdychova, V; Zuber, K

    2015-01-01

    Cross-sections for the proton-induced reactions on natural neodymium in energy regions 5-10 MeV and 30-35 MeV were measured using the cyclotron U-120M at the Nuclear Physics Institute at Rez near Prague. This measurement completes the investigation previously done in the 10-30 MeV energy range. Results revealed practical production thresholds and secondary maxima and minima in the excitation functions. It allowed for more appropriate calculation of thick target yields and production rates of many longer-lived radionuclides potentially disturbing the search for neutrinoless double beta decay. Measured cross-sections are consistent with our previously published data.

  17. Production of plutonium tracers in Np-237 nuclear reactions with He-3-ions in the energy range from 26 to 60 MeV

    Aaltonen, J; Dendooven, P; Gromova, EA; Jakovlev, VA; Trzaska, WH

    1998-01-01

    Cross-sections for the reaction Np-237 + He-3 --> Pu-236,Pu-237,Pu-238 at He-3 bombarding energies from 26 to 60 MeV were measured. Thick-target yields, based on the measured and previously known cross-sections were constructed. The results are discussed and compared with Ether reactions leading to

  18. Measurement of the cross-section of the process e+e- → π+π- at the CMD-2 detector in the 370-520 MeV energy range

    The cross sections of the process e+e- → π+π- have been measured in the c.m. energy range 370-520 MeV. The systematic error of measurements is 0.7%. The electromagnetic radius of pion is calculated in the vector dominant model by means of all CMD-2 detector data about pion form factor. The cross section of muon production is measured in the energy range of this experiment

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

    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.

  20. Gamma ray production cross sections in proton induced reactions on natural Mg, Si and Fe targets over the proton energy range 30 up to 66 MeV

    Yahia-Chérif, W; Kiener, J; Tatischeff, V; Lawrie, E; Lawrie, J J; Belhout, A; Benhabiles, H; Bucher, T D; Chafa, A; Damache, S; Debabi, M; Deloncle, I; Easton, J L; Hamadache, C; Hammache, F; Jones, P; Kheswa, B V; Khumalo, N; Lamula, T; Majola, S T H; Negi, D; Ndayishimye, J; Noncolela, S P; Moussa, D; Nchodu, R; Papka, P; de Sereville, N; Sharpey-Schafer, J F; Shirinda, O; Wiedeking, M; Wyngaardt, S

    2015-01-01

    Gamma-ray excitation functions have been measured for 30, 42, 54 and 66 MeV proton beams accelerated onto C + O (Mylar), Mg, Si, and Fe targets of astrophysical interest at the separate-sector cyclotron of iThemba LABS in Somerset West (Cape Town, South Africa). A large solid angle, high energy resolution detection system of the Eurogam type was used to record Gamma-ray energy spectra. Derived preliminary results of Gamma-ray line production cross sections for the Mg, Si and Fe target nuclei are reported and discussed. The current cross section data for known, intense Gamma-ray lines from these nuclei consistently extend to higher proton energies previous experimental data measured up to Ep ~ 25 MeV at the Orsay and Washington tandem accelerators. Data for new Gamma-ray lines observed for the first time in this work are also reported.

  1. WISP Dark Matter eXperiment and Prospects for Broadband Dark Matter Searches in the $1\\,\\mu$eV--$10\\,$meV Mass Range

    Horns, Dieter; Lobanov, Andrei; Ringwald, Andreas

    2014-01-01

    Light cold dark matter consisting of weakly interacting slim (or sub-eV) particles (WISPs) has been in the focus of a large number of studies made over the past two decades. The QCD axion and axion-like particles with masses in the $0.1\\,\\mu$eV--$100\\,$meV are strong candidates for the dark matter particle, together with hidden photons with masses below $\\lesssim 100\\,$meV. This motivates several new initiatives in the field, including the WISP Dark Matter eXperiment (WISPDMX) and novel conceptual approaches for broad-band WISP searches using radiometry measurements in large volume chambers. First results and future prospects for these experiments are discussed in this contribution.

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

    This report is in two parts. The first part reports on the experimental work determining the half-life for double beta decay of 238U to 238PU to be (2.0 ± 0.6) x 1021 years. This is the first evidence for a third mode of decay of this heaviest naturally occurring nucleus. This rate is about 106 times slower than spontaneous fission, which itself is about 106 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 238U. The yields at 11.5 MeV are similar to those from 14 MeV neutron fission of 238U. At the same time, the production cross sections of 238Np 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. Total cross section of hadron photoproduction on Be, C, Hsub(2)O and Al nuclei in the energy range Esub(γ)=(200-900) MeV

    New experimental results of the measurement of total cross section of hadron photoproduction on Be, C, H2O and Al nuclei for the photon energy of (0.2-0.9) GeV obtained on the tagged photon beam by means of hadron detectors covering the solid angle approximately 4π are reported. The results are compared with the available data on total cross section of hadron photoproduction. For the oxygen nucleus the comparison is carried out with the theoretical predictions for the photon energy up to 400 MeV

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

    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 (errorenergy 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.

  5. 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 65 MeV

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

    2016-01-01

    Activation cross-sections data of longer-lived products of proton induced nuclear reactions on dysprosium were extended up to 65 MeV 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 36-65 MeV 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.

  6. Neutron-induced fission cross-section of 233U in the energy range 0.5n< 20 MeV

    The neutron-induced fission cross-section of 233U has been measured at the CERN n-TOF facility relative to the standard fission cross-section of 235U between 0.5 and 20MeV. The experiment was performed with a fast ionization chamber for the detection of the fission fragments and to discriminate against α -particles from the natural radioactivity of the samples. The high instantaneous flux and the low background of the n-TOF facility result in data with uncertainties of ∼ 3%, which were found in good agreement with previous experiments. The high quality of the present results allows to improve the evaluation of the 233U (n,f) cross-section and, consequently, the design of energy systems based on the Th/U cycle. (orig.)

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

    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.

  8. Neutron-induced fission cross-section of {sup 233}U in the energy range 0.5MeV

    Belloni, F.; Milazzo, P.M.; Abbondanno, U.; Fujii, K.; Moreau, C. [Istituto Nazionale di Fisica Nucleare (INFN), Trieste (Italy); Calviani, M. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare (INFN), Legnaro (Italy); CERN, Geneva (Switzerland); Colonna, N.; Marrone, S.; Meaze, M.H.; Tagliente, G.; Terlizzi, R. [Istituto Nazionale di Fisica Nucleare (INFN), Bari (Italy); Mastinu, P.; Gramegna, F. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Legnaro (Italy); Aerts, G.; Andriamonje, S.; Berthoumieux, E.; Dridi, W.; Gunsing, F.; Pancin, J.; Perrot, L.; Plukis, A. [CEA, Irfu, Gif-sur-Yvette (France); Alvarez, H.; Cano-Ott, D.; Duran, I.; Embid-Segura, M.; Gonzalez-Romero, E.; Paradela, C. [Univ. de Santiago de Compostela, Santiago (Spain); Alvarez-Velarde, F.; Guerrero, C.; Martinez, T.; Villamarin, D.; Vincente, M.C. [Centro de Investigaciones Energeticas Medioambientales y Technologicas, Madrid (Spain); Andrzejewski, J.; Marganiec, J. [Univ. of Lodz, Lodz (Poland); Audouin, L.; Dillmann, I.; Heil, M.; Kaeppeler, F.; Mosconi, M.; Plag, R.; Voss, F.; Walter, S.; Wisshak, K. [Inst. fuer Kernphysik, Karlsruhe Inst. of Technology, Campus Nord, Karlsruhe (Germany); Badurek, G.; Jericha, E.; Leeb, H.; Oberhummer, H.; Pigni, M.T. [Technische Univ. Wien, Atominstitut der Oesterreichischen Univ., Wien (Austria); Baumann, P.; David, S.; Kerveno, M.; Lukic, S.; Rudolf, G. [Centre National de la Recherche Scientifique/IN2P3 - IReS, Strasbourg (France); Becvar, F.; Krticka, M. [Charles Univ., Faculty of Mathematics and Physics, Prague (Czech Republic); Calvino, F.; Cortes, G.; Poch, A.; Pretel, C. [Univ. Politecnica de Catalunya, Barcelona (Spain); Capote, R. [NAPC/Nuclear Data Section, International Atomic Energy Agency, Vienna (Austria); Univ. de Sevilla, Sevilla (Spain); Carrapico, C.; Goncalves, I.; Salgado, J.; Santos, C.; Tavora, L.; Vaz, P. [Inst. Tecnologico e Nuclear, Lisbon (Portugal)] [and others

    2011-01-15

    The neutron-induced fission cross-section of {sup 233}U has been measured at the CERN n-TOF facility relative to the standard fission cross-section of {sup 235}U between 0.5 and 20MeV. The experiment was performed with a fast ionization chamber for the detection of the fission fragments and to discriminate against {alpha} -particles from the natural radioactivity of the samples. The high instantaneous flux and the low background of the n-TOF facility result in data with uncertainties of {approx} 3%, which were found in good agreement with previous experiments. The high quality of the present results allows to improve the evaluation of the {sup 233}U (n,f) cross-section and, consequently, the design of energy systems based on the Th/U cycle. (orig.)

  9. Electron transport simulation in the range 1 keV-4 MeV for the purpose of high-resolution dosimetric application

    Cobut, V. [Univ. de Cergy-Pontoise, Neuville/Oise (France). Lab. Pharmacophores Redox, Phytochimie et Radiobiologie; Cirioni, L.; Patau, J.P. [Univ. Paul Sabatier, Toulouse (France). Faculte de Pharmacie

    2001-07-01

    Experimental spectrometry and dosimetry can offer some reliable answers. However, they are not easy to implement in some specific situations. Furthermore, information on dose distributions cannot always be obtained with the desirable geometrical resolution. A way to get rid of these disadvantages consist in simulating every successive individual interactions suffered by electrons and photons along their path. We applied this principle to simulate the response of a detector placed in the field of beta-gamma sources, which maximum energy does not exceed 4 MeV. A part of this work is presented here, which concerns Monte Carlo simulation of electron transport in materials encountered in experimental dosimetric devices. Electrons were followed down to a cutoff energy of 1 keV. (orig.)

  10. McSUB, a Monte Carlo Library for neutron transport in two different media for the neutron energy range 0.1-20 MeV

    Library McSUB is a package of easy-to-use subroutines and functions treating neutron transport in two different kind of media by Monte Carlo calculations. The first medium, D0, contains deuterium and natural carbon while the second medium, D1, contains hydrogen and natural carbon. In the neutron energy interval 0.1-20 MeV eight different kinds of interactions are considered: Elastic and (n,2n) interactions with deuterium, elastic interactions with hydrogen and elastic and inelastic interactions with natural carbon. The inelastic interaction with carbon are subdivided into four different interaction classes, one for each excited state of the recoiled carbon nucleus. The neutron cross sections and Legendre coefficients (expressing differential cross sections) have been supplied by NEA Data Bank in France. (author)

  11. Heavy-ion induced damage of crystalline Ge and W at 0.5 to 8 A · MeV range

    High energy heavy-ion induced damage of the Ge and W crystals was studied by means of blocking and channeling. Beams of ions from C to Au with energies from 12 to 266 MeV were used both for the damage of the crystal and for the 'in-situ' measurements of the lattice disordering. The blocking minimum yield and angular half-width have been measured as a function of dose, and it is shown that the ion relative damaging efficiency for Ge decreases at high electronic energy-loss values. The mechanism of microannealing along the ion path is discussed. The saturation and dose-rate dependence of damage are explained in terms of the defect mobility and recombination processes. For W crystal the initial damaging power is proportional to the TRIM predicted displacements, and a disorder saturation is observed at high doses

  12. Study of excited states of the nucleus 12C in the range of overlapping resonances using the proton scattering on 11B and the nuclear reaction 11B(p,α0)8Be in the energy range Ep = 4.5 ... 7.5 MeV

    Using a partial wave analysis the angular distributions measured for the reactions 11B (p,p') 11B* and 11B (p,a) 8Be in the energy range from 4.5 to 7.5 MeV the resonance states of 12C were determined including level widths, spin, parity, and isopin. (HSI)

  13. 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 65 MeV

    Activation cross-sections data of longer-lived products of proton induced nuclear reactions on dysprosium were extended up to 65 MeV by using stacked foil irradiation and gamma spectrometry experimental methods. Experimental cross-sections data for the formation of the radionuclides 159Dy, 157Dy, 155Dy, 161Tb, 160Tb, 156Tb, 155Tb, 154m2Tb, 154m1Tb, 154gTb, 153Tb, 152Tb and 151Tb are reported in the 36–65 MeV 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. - Highlights: • Proton induced reactions on natural dysprosium up to 65 MeV. • Stacked foil irradiation including monitor and energy degrader foils. • Comparison of experimental results with the ALICE, EMPIRE and TALYS theoretical codes. • Calculation and comparison of thick target integral yields. • Discussion of application fields

  14. Study of the Dynamics in a Linac Booster for Proton Therapy in the 30-62 MeV Energy Range

    Vaccaro, Vittorio G; De Martinis, Carlo; Giove, Dario; Lanzone, S; Masullo, Maria R; Mauri, Marco; Rainò, Antonio; Variale, Vincenzo

    2005-01-01

    Recent results in accelerator physics have shown the feasibility of a coupling scheme between a cyclotron and a linac for proton acceleration. Cyclotrons with energies up to 30 MeV, mainly devoted to radioisotopes production, are available in a large number of medical centres. These two evidences have suggested the idea to study and design a linac booster able to increase the initial proton energy up to the values required for the treatment of tumors, like the ocular ones. Among the challenges in such a project one of the main ones is related to meet the requirement of having sufficient mean current for therapy from a given injection current coming from the cyclotron. In this paper we will review the rationale of the project in order to optimize the transmittance and to minimize the duty-cycle. In this frame we will discuss the basic design of a compact 3GHz linac with a new approach to the cavities used in a SCL (Side Coupled Linac) structure.

  15. Neutron cross section evaluations of europium isotopes in 1 keV - 30 MeV energy range. Format - validation - comparison; Evaluation de sections efficaces pour des neutrons incidents sur des isotopes d'europium aux energies 1 keV - 30 MeV. Format - validation - comparaison

    Dossantos-Uzarralde, P.; Le Luel, C.; Bauge, E. [CEA Bruyeres le Chatel, 91 (France). Dept. de Physique Theorique et Appliquee

    2004-07-01

    This paper presents neutron cross section evaluations of Europium isotopes. The cross sections are evaluated in 1 keV - 30 MeV energy range for the isotopes {sup 146}Eu, {sup 147}Eu, {sup 148}Eu, {sup 149}Eu, {sup 150}Eu, {sup 151}Eu, {sup 152}Eu, {sup 153}Eu, {sup 154}Eu in their ground state. This evaluation includes cross section productions of the long life isomeric states. Special attention is put on the options used for the description of the files written in ENDF-6 format. The final issue is a proposal of a new breed of ENDF-6 formatted neutron activation file. (authors)

  16. Study of the process $e^+ e^- \\to K\\overline{K}$ in the center-of-mass energy range 1004--1060 MeV with the CMD-3 detector at $e^+ e^-$ VEPP-2000 collider

    Kozyrev, E A

    2016-01-01

    The $e^+ e^- \\to K^0_{S}K^0_{L}$ and $e^+ e^- \\to K^{-}K^{+}$ cross sections have been measured in the center-of-mass energy range 1004--1060 MeV for 25 energy points with about 2$\\div$3\\% systematic uncertainties. The analysis is based on 5.5 pb$^{-1}$ of integrated luminosity collected with the CMD-3 detector at the VEPP-2000 $e^+ e^-$ collider. The measured cross section is approximated according to Vector Meson Dominance model as a sum of $\\phi, \\omega, \\rho$-like amplitudes and their excitations, and $\\phi(1020)$ meson parameters have been obtained.

  17. Method for determination of the average parameters of the dispersion optical potential for p+A in the range of 40 ≤ A ≤ 208 and -60 ≤ E ≤ 65 MeV

    The method for determination of the average parameters of the proton dispersion optical potential, applicable in the area of the nuclei mass numbers 40 ≤ A ≤ 208 and within the energy range of -60 ≤ E ≤+65 MeV is proposed. Application of the average parameters makes it possible to reliable forecast the differential cross sections of elastic scattering and polarization, complete cross sections of reactions, characteristics of the single-particle proton stets in the A-1 and A+1 nuclei

  18. Experimental study of deuteron production in α-particle collisions with C, Cu and Pb target nucleus at energies ranging from 200 to 800 A. MeV

    Deuteron production in collisions between alpha-particle and carbon, copper or lead target nuclei at 200, 400, 600 and 800 MeV (Mega-electron Volt) per nucleon have been measured by using the large solid angle detector DIOGENE. Nucleus-nucleus collisions at intermediate energies offer the possibility of studying the properties of highly excited nuclear matter at high density and temperature. Among the different observables measured for the determination of the nuclear matter equation of state, light fragment production measurements has raised considerable interest during the last years because of the close relationship between entropy and nuclear cluster formation. In chapter 1, a general presentation of the main experimental and theoretical aspects of the relativistic heavy ion collision is presented. Chapter 2 is devoted to the description of the detector DIOGENE used at the SATURNE (Saclay-France) accelerator. This detector can measure simultaneously the momenta, masses and emission angles of most of the particles (pions, protons, deuterons ...) emitted in each collision. The chapter 3 describes the method used in order to extract from the raw data the momentum, mass and emission angles of each particle measured in the detector. The deuteron production in central relativistic heavy ion collision is reviewed in chapter 4. Then we present the results of deuteron production measurements, using the DIOGENE detector. In chapter 5 deuteron differential cross-sections are compared with theoretical predictions obtained with intra-nuclear cascade model. In chapter 6 deuteron differential cross-sections are presented for the most central reactions. These spectra are investigated in order to extract the size of the interaction region at the end of the collision. Finally the deuteron-to-proton ratio is studied in relationship with the proton number measured in each event; this ratio is used to evaluate the entropy per nucleon in the most central collisions

  19. Energy dependence of relative abundances and periods of separate groups of delayed neutrons at neutron induced fission of 239Pu in a range of neutrons energies 0.37 - 5 MeV

    The fundamental role of delayed neutrons in behavior, control and safety of reactors is well known today. Delayed neutron data are of great interest not only for reactor physics but also for nuclear fission physics and astrophysics. The purpose of the present work was the measurement of energy dependence of delayed neutrons (DN) group parameters at fission of nuclei 239Pu in a range of energies of primary neutrons from 0.37 up to 5 MeV. The measurements were executed on installation designed on the basis of the electrostatic accelerator of KG - 2.5 SSC RF IPPE. The data are obtained in 6-group representation. It is shown, that there is a significant energy dependence of DN group parameters in a range of primary neutrons energies from thermal meanings up to 5 MeV, which is expressed in reduction of the average half-life of nuclei of the DN precursors on 10 %. The data, received in the present work, can be used at creation of a set of group constants for reactors with an intermediate spectrum of neutrons. (authors)

  20. A study of e+e- annihilation in the 1400-2250 MeV energy range with the magnetic detector DM2 at DCI

    We present here the results obtained with the magnetic detector DM2 on the Orsay e+e- colliding beams DCI for 1400 -1 over the whole energy range. Cross sections are given for e+e- annihilation into pantip, π+π-π0, π+π-π+π- and K+K-

  1. Fusion and transfer cross sections of He-3 induced reaction on Pt and Au in energy range 10-24.5 MeV

    Skobelev, N. K.; Penionzhkevich, Y. E.; Voskoboynik, E. I.; Kroha, Václav; Burjan, Václav; Hons, Zdeněk; Mrázek, Jaromír; Piskoř, Štěpán; Šimečková, Eva; Kugler, Andrej

    2014-01-01

    Roč. 11, č. 2 (2014), s. 114-120. ISSN 1547-4771 R&D Projects: GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : cross section * energy range * Coulomb barrier Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  2. Finite range distorted wave analysis of 139.2 MeV 16O(α, αd)14N reaction

    Experimental and theoretical studies of cluster knockout reactions has been done for the past several decades to study the cluster structure as well as to yield the cluster spectroscopic factor in light to medium mass nuclei. Similar calculations have been performed for the carbon knockout reactions using carbon beam. The absolute spectroscopic factors obtained from the Finite Range-Distorted Wave Impulse Approximation (FR-DWIA) calculations were found to be consistent with the structure estimates

  3. Measurements of the ratio fo 239Pu and 235U fission cross sections in the 0.024-7.4 MeV neutron energy range

    Aimed at improving the accuracy of available nuclear data 239Pu-to-235U fission cross section ratios were measured in a broad range of neutron energies. The measurements were taken in electrostatic accelerators with the Li(p,n)-,T(p,n)- and D(d,n) reactions used as neutron sources. The fission fragments were registered by a twin ionization chamber. The measured energy dependence curve of the fission cross section ratios was calibrated by means of an auxiliary technique employing glass detectors. The quantity ratio of the fissioning nuclei in 239Pu- and 235U layers was determined by two independent methods: from the alpha-activity in the layers and by taking measurements in the reactor thermal column. The total errors in the measured results makes up 1.4 to 1.5% for the most portion of the investigated neutron energy range, while rowing up to 1.7 to 2% in the range below 100 keV

  4. Analysis of the Nb(n,xn) and Bi(n,xn) reaction in the 5-27 MeV incident neutron energy range

    Results of a detailed study of the generation of neutron emission spectra, taking into account the contribution of the pre-equilibrium decay and direct reaction mechanisms to the formation of the compound nucleus are presented. Main consideration is given to the determination of the nuclear level density in the neutron inelastic scattering channel which is the primary contributor to the shape of the soft part of neutron emission spectra. A good description of the experimentally observed spectra over the whole energy range was obtained. The level density parameters which were determined are in good agreement with those taken from well known systematics in the case of Nb, but not in the case of Bi. (author). 29 refs, 12 figs, 2 tab

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

    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 Eo and 90o with respect to the beam-line. Here the ERBSS of UAB (Universidad Autonoma de Barcelona-Grup de Fisica 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 calibrated, is important for guaranteeing the robustness of the measured spectra and estimating their overall uncertainties.

  6. 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

    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.

  7. Proton induced K X-ray production cross sections of the elements Al, Si, Ti, Fe, and Ni in the 0.7-2.0 MeV energy range

    Bertol, Ana Paula Lamberti; Hinrichs, Ruth; Vasconcellos, Marcos A. Z.

    2015-12-01

    Proton induced K-shell ionization cross sections were obtained for the elements Al, Si, Ti, Fe, and Ni in the 0.7-2.0 MeV energy range. The accuracy of these fundamental parameters is essential for PIXE analysis and the data in the literature present a considerable spread, mainly for Al and Si. The values obtained for Ti, Fe and Ni are compatible with the current theories and the experimental results reported in the literature. However, Al and Si cross sections present important differences from theoretical and experimental data. We propose values for the fluorescent yields of Al and Si that are compatible with recent results and can be incorporated in the computations of K X-ray production cross sections.

  8. 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

    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.

  9. Study of the process $e^+ e^- \\to K^0_{S}K^0_{L}$ in the center-of-mass energy range 1004--1060 MeV with the CMD-3 detector at the VEPP-2000 $e^+ e^-$ collider

    Kozyrev, E A

    2016-01-01

    The $e^+ e^- \\to K^0_{S}K^0_{L}$ cross section has been measured in the center-of-mass energy range 1004--1060 MeV at 25 energy points using $6.1 \\times 10^5$ events with $K^0_{S}\\to \\pi^+\\pi^-$ 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 $\\phi(1020)$ meson parameters the measured cross section is approximated according to the Vector Meson Dominance model as a sum of the $\\rho, \\omega, \\phi$-like amplitudes and their excitations. This is the most precise measurement of the $e^+ e^- \\to K^0_{S}K^0_{L}$ cross section with a 1.8\\% systematic uncertainty.

  10. Elastic recoil cross section determination of 1H by 4He ions at 30° and energy range of 1.6–6.0 MeV

    In this paper, the differential cross-section for forward recoiling 1H with 4He ions has been determined in the energy range of 1.6–6.0 MeV at a laboratory angle of 30°. A film of ∼54 nm TiHx on the Si substrate with an overlayer of ∼7 nm Ta on the TiHx foil was used as the target, and hydrogen loss of the target due to ion bombardment can be fully ignored (<0.1%) through the whole measurement. A method of relative determination for the cross-section measurement was employed to be free from absolute determination of hydrogen content in the target as well as absolute measurements of beam dose and solid angles of the detectors. The uncertainty of the determination is less than 5.2%

  11. Measurement of the differential cross sections of the reaction γ+p → π++n at mean production angles and photon energies from 735 to 2005 MeV and parametrization of the c.m. angular distributions in the energy range from 300 to 1985 MeV

    In this experiment the differential cross sections of the reaction γp → π+n in the photon energy interval from 735 MeV to 2005 MeV under the pion laboratory angle of 330 and 60.80 were measured. (orig./HSI)

  12. Measurements of {sup 67}Ga production cross section induced by protons on {sup nat}Zn in the low energy range from 1.678 to 2.444 MeV

    Wachter, J.A., E-mail: javier.wachter@utem.cl [Departamento de Física, Facultad de Ciencias Naturales, Matemática y del Medio Ambiente, Universidad Tecnológica Metropolitana, Santiago 7800002 (Chile); Miranda, P.A. [Departamento de Física, Facultad de Ciencias Naturales, Matemática y del Medio Ambiente, Universidad Tecnológica Metropolitana, Santiago 7800002 (Chile); Morales, J.R.; Cancino, S.A. [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Correa, R. [Departamento de Física, Facultad de Ciencias Naturales, Matemática y del Medio Ambiente, Universidad Tecnológica Metropolitana, Santiago 7800002 (Chile)

    2015-02-01

    The experimental production cross section for the reaction {sup nat}Zn(p,x){sup 67}Ga has been measured in the energy range from 1.678 to 2.444 MeV. The methodology used in this work is based on characteristic X-ray emitted after irradiation by the daughter nuclei that decays by electron capture (EC) and the use of a complementary PIXE experiment. By doing so, expressions needed to determine cross section values are simplified since experimental factors such as geometric setup and an detector efficiency are avoided. {sup 67}Ga is a radionuclide particularly suited for this method since it decays by electron capture in 100% and the subsequent characteristic X-ray emission is easily detected. Natural zinc targets were fabricated by PVD technique and afterwards their thicknesses were determined by Rutherford Backscattering Spectrometry. Cross sections measurements were carried out by using the Van de Graaff accelerator located at Faculty of Sciences, University of Chile. It was found that our data for the {sup nat}Zn(p,x){sup 67}Ga reaction are, in general, in good agreement when compared to existing experimental data and to those calculated ALICE/ASH nuclear code. On the other hand, values predicted by Talys-1.6 are showing systematically lower magnitudes than our measured data.

  13. Measurements of 67Ga production cross section induced by protons on natZn in the low energy range from 1.678 to 2.444 MeV

    The experimental production cross section for the reaction natZn(p,x)67Ga has been measured in the energy range from 1.678 to 2.444 MeV. The methodology used in this work is based on characteristic X-ray emitted after irradiation by the daughter nuclei that decays by electron capture (EC) and the use of a complementary PIXE experiment. By doing so, expressions needed to determine cross section values are simplified since experimental factors such as geometric setup and an detector efficiency are avoided. 67Ga is a radionuclide particularly suited for this method since it decays by electron capture in 100% and the subsequent characteristic X-ray emission is easily detected. Natural zinc targets were fabricated by PVD technique and afterwards their thicknesses were determined by Rutherford Backscattering Spectrometry. Cross sections measurements were carried out by using the Van de Graaff accelerator located at Faculty of Sciences, University of Chile. It was found that our data for the natZn(p,x)67Ga reaction are, in general, in good agreement when compared to existing experimental data and to those calculated ALICE/ASH nuclear code. On the other hand, values predicted by Talys-1.6 are showing systematically lower magnitudes than our measured data

  14. Differential cross section measurements of 27Al(p,p/γ)27Al and 27Al(p,αγ)24Mg reactions in the energy range of 1.6-3.0 MeV

    Jokar, A.; Kakuee, O.; Lamehi-Rachti, M.; Sharifzadeh, N.; Fathollahi, V.

    2015-11-01

    In this work measurement of differential cross sections of 27Al(p,p/γ)27Al (Eγ = 844, 1014 keV) and 27Al(p,αγ)24Mg (Eγ = 1369 keV) nuclear reactions in the proton energy range of 1.6-3.0 MeV are described and the measured values are presented. Thin Al target was prepared by evaporating a 26 μg/cm2 Al onto a 129 μg/cm2 self-supporting Ag film. The gamma-rays and backscattered protons were detected simultaneously. The gamma-rays and protons were collected by an HPGe detector placed at an angle of 90° with respect to beam direction and an ion implanted Si detector placed at a scattering angle of 165°, respectively. In this experimental setup the great advantage is that differential cross sections could be independent on absolute values of the collected beam charge. The overall systematic uncertainty of cross sections was estimated to be ±9% while statistical errors were less than ±5%.

  15. 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

    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.

  16. Within the framework of the new fuel cycle 232Th/233U, determination of the 233Pa(n.γ) radiative capture cross section for neutron energies ranging between 0 and 1 MeV

    The Thorium cycle Th232/U233 may face brilliant perspectives through advanced concepts like molten salt reactors or accelerator driven systems but it lacks accurate nuclear data concerning some nuclei. Pa233 is one of these nuclei, its high activity makes the direct measurement of its radiative neutron capture cross-section almost impossible. This difficulty has been evaded by considering the transfer reaction Th232(He3,p)Pa234* in which the Pa234 nucleus is produced in various excited states according to the amount of energy available in the reaction. The first chapter deals with the thorium cycle and its assets to contribute to the quenching of the fast growing world energy demand. The second chapter gives a detailed description of the experimental setting. A scintillation detector based on deuterated benzene (C6D6) has been used to counter gamma ray cascades. The third chapter is dedicated to data analysis. In the last chapter we compare our experimental results with ENDF and JENDL data and with computed values from 2 statistical models in the 0-1 MeV neutron energy range. Our results disagree clearly with evaluated data: our values are always above ENDF and JENDL data but tend to near computed values. We have also perform the measurement of the radiative neutron cross-section of Pa231 for a 110 keV neutron: σ(n,γ) 2.00 ± 0.14 barn. (A.C.)

  17. Spin-flip (p,n) reactions on 26Mg, 54Fe, and 56Fe at selected proton bombarding energies in the range of 17 to 25 MeV

    New data are presented for the 26Mg(p,n)26Al reaction at E/sub p/ = 19.12 and 24.97 MeV, for the 54Fe(p,n)54Co reaction at E/sub p/ = 17.20, 18.60, and 24.60 MeV, and for the 56Fe(p,n)56Co reaction at E/sub p/ = 19.12 and 24.59 MeV. Data were taken with the LLNL Cyclograaff at 16 angles from 3.50 to 159.00. A large detector at 23.80 with a long neutron flight path collected high resolution spectra. This large detector also collected separate 00 high resolution data on the 26Mg and 56Fe(p,n) reactions at E/sub p/ = 19 MeV. Absolute differential (p,n) cross sections were extracted for 1+ states in 26Al, 54Co, and 56Co, for the 0+ isobaric analong state (IAS) in 54Co and 56Co, for a 2+ state in each residual nucleus, and for the 0.199 MeV 7+ state of 54Co. No new experimental states were identified. Only relative cross sections were extracted at 00. Experimental angle-integrated cross sections were obtained for all but one state. DWBA79 was used, with the G-matrix effective nucleon-nucleon interaction of Bertsch et al. (with the central triplet-odd component V/sub to/ = O) and the Livermore shell model wave functions to calculate differential (p,n) cross sections to 1+ states and to the 54Co and 56Co IAS. Normalization of the DWBA angle-integrated cross sections to measurements for the 54Co and 56Co IAS (at E/sub p/ = 24.6 MeV) yielded the renormalized V/sub tau/ = 21.4 +- 2.1 MeV. Normalization of the DWBA angle-integrated cross sections to measurements for the 24.6 MeV 54Co and 56Co 1+ states, coupled with the normalization of the wave functions to previously experimentally determined GT strength, yield the renormalized V/sub sigmatau/ = 12.3 +- 1.2 MeV. The experimental Gamow-Teller strength B(GT)/sub exp./ of the T = 1 26Al state at 9.44 MeV was found to be 0.69; B(GT)/sub exp/ of the T = 1 26Al state at 10.47 MeV was found to be 0.39

  18. Secondary electron emission of thin carbon foils under the impact of hydrogen atoms, ions and molecular ions, under energies within the MeV range; Multiplicite des electrons secondaires emis par des cibles minces de carbone sous l'impact de projectiles H0, H2+, H3+ d'energie de l'ordre du MeV

    Vidovic, Z

    1997-06-15

    This work focuses on the study of the emission statistics of secondary electrons from thin carbon foils bombarded with H{sup 0}, H{sub 2}{sup +} and H{sub 3}{sup +} projectiles in the 0.25-2.2 MeV energy range. The phenomenon of secondary electron emission from solids under the impact of swift ions is mainly due to inelastic interactions with target electrons. The phenomenological and theoretical descriptions, as well as a summary of the main theoretical models are the subject of the first chapter. The experimental set-up used to measure event by event the electron emission of the two faces of a thin carbon foil traversed by an energetic projectile is described in the chapter two. In this chapter are also presented the method and algorithms used to process experimental spectra in order to obtain the statistical distribution of the emitted electrons. Chapter three presents the measurements of secondary electron emission induced by H atoms passing through thin carbon foils. The secondary electron yields are studied in correlation with the emergent projectile charge state. We show the peculiar role of the projectile electron, whether it remains or not bound to the incident proton. The fourth chapter is dedicated to the secondary electron emission induced by H{sub 2}{sup +} and H{sub 3}{sup +} polyatomic ions. The results are interpreted in terms of collective effects in the interactions of these ions with solids. The role of the proximity of the protons, molecular ion fragments, upon the amplitude of these collective effects is evidenced from the study of the statistics of forward emission. These experiences allowed us to shed light on various aspects of atom and polyatomic ion inter-actions with solid surfaces. (author)

  19. Elastic Neutron Scattering at 96 MeV from {sup 12}C and {sup 208}Pb

    Klug, J.; Blomgren, J.; Atac, A. [and others

    2003-04-01

    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 The Svedberg Laboratory, Uppsala. Elastic neutron scattering from {sup 12}C and {sup 208}Pb has been studied at 96 MeV in the 10-70 deg 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 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.

  20. Elastic Neutron Scattering at 96 MeV from 12C and 208Pb

    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 The Svedberg Laboratory, Uppsala. Elastic neutron scattering from 12C and 208Pb has been studied at 96 MeV in the 10-70 deg 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 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

  1. The analyzing power Asub(y)(THETA) for 12C(n vector,nsub(0,1))12C in the neutron energy range from 6.8 to 17.3 MeV

    The analyzing power for the elastic and inelastic neutron scattering to the first excited state on 12C was measured at 21 energies from 6.8 to 17.3 MeV. The data from 8.9 to 14.9 MeV were together with very precise cross section data from the literature studied in the framework of the spherical optical model and the coupled channel formalism. The coupled channel analysis of the elastic and inelastic scattering on 12C in the framework of the rotator model yielded a good agreement between measured and calculated angular distributions. The determined quadrupole deformation parameter β2 = -0.67 agrees well with values from the literature. The existence of different qudrupole deformations for the central and spin-orbit components of the optical potential was studied. Large differences for the quadrupole deformations β2sup(c) and β2sup(so) were found at 8.9, 11.9, and 12.9 MeV. Especially at 8.9 MeV by this a great improvement of the fit to the data was reached. (orig./HSI)

  2. Energy dependent response of the Fricke gel dosimeter prepared with 270 Bloom gelatine for photons in the energy range 13.93 keV-6 MeV

    Cavinato, C.C. [Instituto de Pesquisas Energeticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, 05508-000 Sao Paulo, SP (Brazil); Campos, L.L., E-mail: lcrodri@ipen.b [Instituto de Pesquisas Energeticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, 05508-000 Sao Paulo, SP (Brazil)

    2010-07-21

    The spectrophotometric energy dependent response to photons with effective energies between 13.93 keV and 6 MeV of the Fricke xylenol gel (FXG) dosimeter developed at IPEN, prepared using 270 Bloom gelatine, was evaluated in order to verify the possible dosimeter application in other medicine areas in addition to radiosurgery, for example, breast radiotherapy and blood bags radiosterilization. Other dosimetric characteristics were also evaluated. The obtained results indicate that the FXG dosimeter can contribute to dosimetry in different medical application areas including magnetic resonance imaging (MRI) evaluation technique that permits three-dimensional (3D) dose distribution evaluation.

  3. Energy dependent response of the Fricke gel dosimeter prepared with 270 Bloom gelatine for photons in the energy range 13.93 keV-6 MeV

    The spectrophotometric energy dependent response to photons with effective energies between 13.93 keV and 6 MeV of the Fricke xylenol gel (FXG) dosimeter developed at IPEN, prepared using 270 Bloom gelatine, was evaluated in order to verify the possible dosimeter application in other medicine areas in addition to radiosurgery, for example, breast radiotherapy and blood bags radiosterilization. Other dosimetric characteristics were also evaluated. The obtained results indicate that the FXG dosimeter can contribute to dosimetry in different medical application areas including magnetic resonance imaging (MRI) evaluation technique that permits three-dimensional (3D) dose distribution evaluation.

  4. Calculation of neutron cross sections for 90Zr, 208Pb and 209Bi in the energy range of 0.5-25 MeV by using the optical model potentials

    Neutron total cross sections and differential elastic scattering cross sections for the nuclides 90Zr, 208Pb and 209Bi were calculated using different global spherical optical potential (SOP) parameter sets at neutron energies from 0.5-25 MeV. Calculated cross sections for the corresponding nuclides were compared with their experimental data obtained by the EXFOR file to select the best fit parameter sets. It is found that the parameter sets of Ferer Rapaport for 90Zr and Bechetti and Greenless for 208Pb and 209Bi are the best fitted set to obtain the experimental data of total cross sections and angular distributions of these nuclides. (author)

  5. Performance of TEPCs at low pressures: some attempts to improve their dose equivalent response to the neutron energy range from 10keV to 1 MeV

    A TEPC, from its operational principle, fulfils reasonably well the requirements of an area monitor with a dose equivalent response nearly independent of neutron energy to be used for radiation protection dosimetry at various work places. However, between neutron energies from 10 keV to 1 MeV, which are of relevance for environments with strongly moderated neutron fields, the response of TEPCs with thin walls is too low. Attempts to increase the response in this energy region by modifying gas pressure, gas composition and wall thickness show that significant improvement first requires operation of the TEPC at lower simulated diameters compared with the 2 μm diameter commonly used. Preliminary investigations to improve the operational properties of TEPCs at low pressures are presented. (author)

  6. MeV fullerene impacts on mica

    Doebeli, M.; Scandella, L. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Ames, F. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1997-09-01

    Hillock heights on mica irradiated with MeV C{sub 60} ions have been investigated systematically. Results show that the small range of secondary particles along the track plays a crucial role in defect production. (author) figs., tab., refs.

  7. Review of neutron data: 10 to 40 MeV

    Neutron data are reviewed for incident neutron energies between 10 and 40 MeV. A census of the data shows that there are many gaps in this range and that the existing data are primarily for neutron energies around 14 MeV. Aside from total cross sections, there are few data between 10 and 13 MeV and between 15 and 40 MeV. Examples are presented to show the quality of selected data for total, elastic, inelastic, activation, and charged-particle and gamma-ray production cross sections. The spectra of emitted particles are also discussed

  8. Neutron photoproduction in sup 2 sup 3 sup 2 Th and sup 2 sup 3 sup 8 U using thermal neutron capture gamma-rays in the energy range 5.61 to 10.83 MeV

    Goncalez, O L

    1998-01-01

    Neutron photoproduction studies for sup 2 sup 3 sup 2 Th and sup 2 sup 3 sup 8 U were carried out from 5.6 to 10.8 MeV, using neutron capture gamma-rays with high resolution in energy (3 to 21 eV), produced by 30 target materials, placed inside a tangential beam port, near the core of the IPEN/CNEN-SP IEA-R1 2 MW research reactor. The samples (17.76 g of U sub 3 sub O sub 8 depleted to 0.349% in sup 2 sup 3 sup 5 U and 19.93 g of natural Th O sub 2) have been irradiated inside a 4 pi geometry neutron detector system sup L ong Counter sup , 520.5 cm away from the capture target. The capture gamma-ray flux was determined by means of the analysis of the gamma spectrum obtained by using a Ge(Li) solid-state detector (E G and G Ortec, 25 cm sup 3 , 5%), previously calibrated with capture gamma-rays from a standard target of Nitrogen (Melamine). The neutron photoproduction cross section has been measured for each target capture gamma-ray spectrum (compound cross section). A methodology for unfolding the set of expe...

  9. Excitation functions of proton-induced reactions on natural Nd in the 10-30 MeV energy range, and production of radionuclides relevant for double-{\\beta} decay

    Lebeda, O; Schrock, P; Štursa, J; Zuber, K; 10.1103/PhysRevC.85.014602

    2012-01-01

    A preferred candidate for neutrinoless double-{\\beta} decay, 150Nd, is present in natural neodymium at an abundance level of 5.64%. However, neodymium could be activated by cosmic rays during the period it spends on the Earth's surface. Its activation by protons is therefore of interest when it comes to estimating the possible disturbance effects and increased background during neutrinoless double-{\\beta}-decay experiments like Sudbury Neutrino Observatory plus liquid scintillator (SNO+). In most cases, we lack experimental data on proton-induced reactions on neodymium. Therefore, a measurement of cross sections has been performed for the formation of 141Pm, 143Pm, 144Pm, 146Pm, 148Pm, 148Pmm, 149Pm, 150Pm, 140Nd, 141Nd, 147Nd, 149Nd, 138Prm, 139Pr, 142Pr, and 139Ce by 10-30 MeV protons. Oxidation-protected metal foil targets of natural isotopic abundance were irradiated by the usual stacked-foil technique on the external proton beam of the isochronous cyclotron U-120M at the Nuclear Physics Institute at \\v{R...

  10. Technical Note: Influence of the phantom material on the absorbed-dose energy dependence of the EBT3 radiochromic film for photons in the energy range 3 keV–18 MeV

    Purpose: Water is the reference medium for radiation therapy dosimetry, but for film dosimetry it is more practical to use a solid phantom. As the composition of solid phantoms differs from that of water, the energy dependence of film exposed within solid phantoms may also differ. The energy dependence of a radiochromic film for a given beam quality Q (energy for monoenergetic beams) has two components: the intrinsic energy dependence and the absorbed-dose energy dependence f(Q), the latter of which can be calculated through a Monte Carlo simulation of radiation transport. The authors used Monte Carlo simulations to study the influence of the phantom material on the f(Q) of the EBT3 radiochromic film (Ashland Specialty Ingredients, Wayne, NJ) for photon beams with energies between 3 keV and 18 MeV. Methods: All simulations were carried out with the general-purpose Monte Carlo code PENELOPE 2011. The geometrical model consisted of a cylindrical phantom, with the film positioned at different depths depending on the initial photon energy. The authors simulated monoenergetic parallel photon beams and x-ray beams from a superficial therapy system. To validate their choice of simulation parameters, they also calculated f(Q) for older film models, EBT and EBT2, comparing with published results. In addition to water, they calculated f(Q) of the EBT3 film for solid phantom materials commonly used for film dosimetry: RW1 and RW3 (PTW-Freiburg, Freiburg, Germany), Solid Water (Gammex-RMI, Madison, WI), and PMMA. Finally, they combined their calculated f(Q) with published overall energy response data to obtain the intrinsic energy dependence of the EBT3 film in water. Results: The calculated f(Q) for EBT and EBT2 films was statistically compatible with previously published data. Between 10 keV and 18 MeV, the variation found in f(Q) of the EBT3 film for water was within 2.3%, with a standard statistical uncertainty less than 1%. If the quantity dose-to-water in the phantom is

  11. Atomic inner shell ionization: a new method of nuclear interaction lifetimes in the range 10-16-10-18 second. Lifetime measurement of the compound nucleus in the reaction 106Cd+p (Ep=10 and 12 MeV)

    A new method to measure the lifetime of the compound nucleus formed in the reaction 106Cd+p at Ep=10 and 12 MeV is described. The nuclear lifetime is compared to the known lifetime of an atomic inner shell vacancy created in the entrance channel of the nuclear reaction. If the ionization probability in he way-in of the nuclear reaction is kown the compound nucleus lifetime is deduced by a simple relation from the number of compound X-rays measured in coincidence with one of the reaction products. A large number of ionization probability values measured in very small impact parameter collisions induced by H+, He+, D+ on Al, Cu, S, Ti, Si, Ag, Cd are reported. The data are interpreted in terms of the corrected SCA theory of ionization. New effects such as angular dependence and trajectory effect (hair-pin-curve effect) are shown experimentally. The influence of a nuclear delay time on the ionization probability value is considered; the effect on a nuclear reaction of the energy losses by the projectile during the ionization process is analysed in detail. The yield curve of the resonant nuclear reaction 27Al(p,γ)28Si is taken as an example. A detailed analysis of the compound nucleus 107In lifetimes is given. Attention has been paid to competitive processes leading to X ray emission of same energy as the compound X rays. Extensions of the method to measure compound nucleus lifetimes in collision induced by heavy ions and to separate the shape elastic and compound elastic mechanisms are presented

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

    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 cm3 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 cm3 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

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

    Salyer, R.L.; VanDenburg, J.W.; Prinja, A.K.; Kirby, T.; Busch, R. [Univ. of New Mexico, Albuquerque, NM (United States); Hong-Nian Jow [Sandia National Laboratories, Albuquerque, NM (United States)

    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.

  14. Ion emission in solids bombarded with Au{sub n}{sup +} (n = 1 - 9) clusters accelerated within the 0.15 - 1.25 MeV energy range; Emission ionique des solides a l'impact d'agregats Au{sub n}{sup +} (n=1-9) acceleres entre 0,15 et 1,25 MeV

    Wehbe, Nimer [Universite Claude Bernard Lyon-I, 43 boulevard du 11 Novembre 1918, 69622 Villeurbanne cedex (France)

    2006-06-15

    This experimental work is devoted to the study of the ion emission in solids at the impact of gold clusters of energies within 0.15 to 1.25 MeV range. The physics of ion-solid collisions and the theoretical models of sputtering of solids under ion bombardment are presented in the first chapter. The chapter no. 2 deals with the description of the experimental setup. The study of a gold target allowed to evidence the role of the size and energy of the clusters in determining the emission intensity and the mass distribution of the ions. The 4. chapter gives results from the study of cesium iodide in which the intense emission of CsI clusters could be investigated quantitatively due to multiplicity measurements. Finally, the chapter no. 5 was devoted to the study of a biologic molecule, the phenylalanine, and of a pesticide molecule, chlorosulfuron. This work evidenced the importance of clusters for surface analyses by mass spectrometry.

  15. Cross sections of electron loss and capture for beams of O{sup +} in water vapor from the energy range of 0,2 to 1,2 MeV; Secoes de choque de perda e captura eletronica para feixes de O{sup +} em vapor de agua em uma faixa de energia entre 0,2 e 1,2 MeV

    Oliveira, Vitor Jesus de

    2015-06-01

    The study of the interactions between atoms and molecules is important for the knowledge of the cross sections of the processes that contribute to the deposition of energy by charged particle beams used in radiotherapy planning and transport particle simulation codes. Heavy ions, such as oxygen, induce many cellular and molecular damages in human cells.as a result of interaction between the projectile and atoms and molecules. The use of proton and carbon as the projectile interacting with water molecules is well characterized, however there are few studies with oxygen ions. In this work we are interested in the study of electron loss (projectile ionization) and electron capture with charge state 1+. The Pelletron accelerator of 1.7 MeV from the Federal University of Rio de Janeiro housed in the Atomic and Molecular collisions Laboratory (LACAM) has been used, which can accelerate atomic and molecular ions up to speeds of the order of hundredths of light speed, and consists of the source of negative ions, the Wien filter, the accelerator itself and the magnet load selector. The detection device used to evaluate the processes of interaction (capture and loss) between the beam of the O{sup +} and the water molecule is a Microchannel Plate (MCP) at the position sensitive anode. The collisions of O{sup +} beans are being studied in the range of 0.2 to 1.2 MeV with water vapor (Z = 10). Were obtained the respective absolute cross sections for electron loss and electron capture and compared with the cross sections of the molecule methane (CH4 → Z = 10), the isoelectronic water molecule. The experimental results show an agreement between the measurements with water and methane. Comparisons were made with results of theoretical models for electron loss using the 'Free Collision Model' and for capture the Bohr and Lindhard model. The theoretical results for electron loss show an agreement of experimental data with the model used. The model of Bohr and Lindhard

  16. Measurements of the 24Mg(d,p0,1,2,3,4) and natMg(d,d0) reactions cross sections in the energy range of 1.2-2 MeV for NRA and EBS applications

    Rafi-kheiri, H.; Kakuee, O.; Lamehi-Rachti, M.

    2016-04-01

    Differential cross sections of the 24Mg(d,p0,1,2,3,4) reactions were obtained in the range Ed,lab = 1.2-2 MeV and at the scattering angles of 90°, 135°, 150° and 165° using a thin Mg target having thickness of 76.7 ± 3.1 μg/cm2. The cross section values were determined with an average energy step of ∼25 keV while the detailed measurements were carried out with an energy step of ∼5 keV around the resonance peaks. Elastic scattering data for three steep backward angles (135°, 150° and 165°) were also studied for the same incident deuteron energy range and steps. The results were compared with those of the previous studies. Moreover, the validity of the measured data has been benchmarked using a thick Mg target at two deuteron beam energies of 1.7 and 2 MeV.

  17. Observation of complete- and incomplete-fusion components in {sup 159}Tb,{sup 169}Tm({sup 16}O,x) reactions: Measurement and analysis of forward recoil ranges at E/A{approx}5-6 MeV

    Singh, Pushpendra P.; Kumar Sharma, Manoj; Unnati; Singh, Devendra P.; Singh, B.P.; Prasad, R. [A. M. University, Accelerator Laboratory, Department of Physics, Aligarh (India); Kumar, Rakesh; Golda, K.S. [Inter-University Accelerator Center, NP Group, P. O. Box No. 10502, New Delhi (India)

    2007-10-15

    With a view to study complete- and incomplete-fusion components in {sup 159}Tb,{sup 169}Tm({sup 16}O,x) reactions, experiments have been carried out at the Inter-University Accelerator Center, New Delhi, India using the 15UD Pelletron accelerator facilities. The forward mean recoil ranges for some radio-nuclides: {sup 168m}Lu, {sup 167}Lu, {sup 167}Yb, {sup 166}Tm produced in the {sup 16}O+{sup 159}Tb system at {approx}90 MeV, and {sup 179}Re, {sup 177}Re, {sup 177}W, {sup 178}Ta and {sup 177}Hf produced in the {sup 16}O+{sup 169}Tm system at {approx}87 MeV have been measured. The recoil-catcher activation technique followed by off-line {gamma}-spectrometry has been employed in the present work. The analysis of forward mean ranges for different radio-nuclides has been done in the framework of the degree of linear momentum transfer from projectile to target nucleus by adopting break-up fusion model considerations. Different complete- and incomplete-fusion components, which may be attributed to the fusion of {sup 16}O and/or {sup 12}C and {sup 8}Be transfer from the {sup 16}O projectile to the target nucleus have been observed. An attempt has also been made to separate out the relative percentage contributions of complete- and incomplete-fusion components using experimentally measured forward recoil ranges. The complete-fusion contributions deduced from recoil range distribution are found to be consistent with the prediction of the theoretical model code PACE. The analysis of data indicates the complete- and incomplete-fusion competition for both the systems at the given energies. (orig.)

  18. Production of no-carrier-added 135La at an 18 MeV cyclotron and its purification for investigations at a concentration range down to 10-15 mol/L

    The production of non-commercially available 135La by proton irradiation of an isotopically enriched [135Ba]BaCO3 target at a cyclotron is described. The purification of the radionuclide was performed by a La-selective resin. 135La was separated in no-carrier-added (n.c.a) form in a nitric acid solution with a radiochemical yield of 83 ± 5% and a total activity per batch of 43 ± 3 MBq. The enriched [135Ba]Ba was recycled to the carbonate form with a recovery of 90 ± 3%. On the basis of a detection limit of 1 Bq/mL, solutions of n.c.a. 135La could be measured down to the 10-15 mol/L concentration range.

  19. Production of no-carrier-added {sup 135}La at an 18 MeV cyclotron and its purification for investigations at a concentration range down to 10{sup -15} mol/L

    Mansel, Alexander; Franke, Karsten [Helmholtz-Zentrum Dresden-Rossendorf, Leipzig (Germany). Reactive Transport Div.

    2015-07-01

    The production of non-commercially available {sup 135}La by proton irradiation of an isotopically enriched [{sup 135}Ba]BaCO{sub 3} target at a cyclotron is described. The purification of the radionuclide was performed by a La-selective resin. {sup 135}La was separated in no-carrier-added (n.c.a) form in a nitric acid solution with a radiochemical yield of 83 ± 5% and a total activity per batch of 43 ± 3 MBq. The enriched [{sup 135}Ba]Ba was recycled to the carbonate form with a recovery of 90 ± 3%. On the basis of a detection limit of 1 Bq/mL, solutions of n.c.a. {sup 135}La could be measured down to the 10{sup -15} mol/L concentration range.

  20. Electret dosemeter response to electrons with energy of 3 Mev, 7 Mev, 11 Mev

    The preliminary results obtained when electret ionization chambers are irradiated with electron of 3, 7, 11 Mev, from 12 mevatron accelerators using a external cop of polyethylene and nylon are presented. (C.G.C.)

  1. 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

    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°.

  2. Differential and channel cross sections for the reactions K0sub(L)p → K0sub(S)p and K0sub(L)p → Λ0π+ in the c.m. energy range 1605 to 1910 MeV

    The differential and channel cross sections have been measured for the reactions K0sub(L)p→ K0sub(S)p and K0sub(L)p → Λ0π+ in nine energy intervals in the c.m. range 1605 to 1910 MeV. The regeneration reaction is a combination of the KN amplitudes with I = 0 and 1) and the KN amplitude (I = 1) and is very sensitive to the various KN phase-shift solutions, some of which show an exotic I=0, P1 resonance. The present results have been expressed in terms of frequency distributions and cross sections, normalised by the Λ0π+ reaction. These results have been compared with the predictions of various partial-wave analyses. Qualitatively one can eliminate the P1 non-resonant solution, though no solution correctly predicts the results. (Auth.)

  3. Differential and channel cross sections for the reactions K0sub(L)p→K0sub(S)p and K0sub(L)p→Λ0π+ in the CM energy range 1605 to 1910MeV

    The differential and channel cross sections have been measured for the reactions K0sub(L)p→K0sub(S)p and K0sub(L)p→Λ0π+ in nine energy intervals in the center of mass range 1605 to 1910 MeV. The regeneration reaction is a combination of the KN amplitudes (with I=0 and 1) and the anti-KN amplitude (I=1) and is very sensitive to the various KN phase shift solutions, some of which show an exotic I=0 P1-resonance. The results have been expressed in terms of frequency distributions and cross sections, normalised by the Λ0π+ reaction. These results have been compared with the predictions of various partial wave analyses. Qualitatively one can eliminate the P1-nonresonant solution though no solution correctly predicts the results

  4. 50 MeV polarimeter

    A description is given of the construction, operation and calibration of the 50 MeV polarimeter which was used at the ZGS. The dependence of the observed counts on various parameters, including the beam polarization, beam intensity and the solid angle in the two polarimeter arms is also discussed

  5. Gamma-Light: High-Energy Astrophysics above 10 MeV

    Morselli, Aldo; Argan, Andrea; Barbiellini, Guido;

    2013-01-01

    The energy range between 10 and 50 MeV is an experimentally very difficult range and remained uncovered since the time of COMPTEL. Here we propose a possible mission to cover this energy range.......The energy range between 10 and 50 MeV is an experimentally very difficult range and remained uncovered since the time of COMPTEL. Here we propose a possible mission to cover this energy range....

  6. Gamma-Light: High-Energy Astrophysics above 10 MeV

    Morselli, Aldo; Argan, Andrea; Barbiellini, Guido; Bonvicini, Walter; Bulgarelli, Andrea; Cardillo, Martina; Chen, Andrew C. N.; Coppi, Paolo; Di Giorgio, Anna Maria; Donnarumma, Immacolata; Del Monte, Ettore; Fioretti, Valentina; Galli, Marcello; Giusti, Manuela; Ferrari, Attilio; Fuschino, Fabio; Giommi, Paolo; Giuliani, Andrea; Labanti, Claudio; Lipari, Paolo; Longo, Francesco; Marisaldi, Martino; Molinari, Sergio; Muñoz, Carlos; Neubert, Torsten; Orleański, Piotr; Paredes, Josep M.; Pérez-García, M.Á.M. Ángeles; Piano, Giovanni; Picozza, Piergiorgio; Pilia, Maura; Pittori, Carlotta; Pucella, Gianluca; Sabatini, Sabina; Striani, Edoardo; Tavani, Marco; Trois, Alessio; Vacchi, Andrea; Vercellone, Stefano; Verrecchia, Francesco; Vittorini, Valerio; Zdziarski, Andrzej; Ivan De Mitri, Nicola Giglietto, Giovanni Marsella, Antonio Surdo

    The energy range between 10 and 50 MeV is an experimentally very difficult range and remained uncovered since the time of COMPTEL. Here we propose a possible mission to cover this energy range.......The energy range between 10 and 50 MeV is an experimentally very difficult range and remained uncovered since the time of COMPTEL. Here we propose a possible mission to cover this energy range....

  7. MeV neutrinos in double beta decay

    Zuber, K.

    1996-01-01

    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 $U_{eh}^2$ of the order 10$^{-7}$ can be derived. Also the possible achievements of upcoming experiments and some consequences are outlined.

  8. The JHP 200-MeV proton linear accelerator

    Kato, Takao [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

    1997-11-01

    A 200-MeV proton linear accelerator for the Japanese Hadron Project (JHP) has been designed. It consists of a 3-MeV radio-frequency quadrupole linac (RFQ), a 50-MeV drift tube linac (DTL) and a 200-MeV separated-type drift tube linac (SDTL). A frequency of 324 MHz has been chosen for all of the rf structures. A peak current of 30 mA (H{sup -} ions) of 400 {mu}sec pulse duration will be accelerated at a repetition rate of 25 Hz. A future upgrade plan up to 400 MeV is also presented, in which annular-coupled structures (ACS) of 972 MHz are used in an energy range of above 150 or 200 MeV. One of the design features is its high performance for a beam-loss problem during acceleration. It can be achieved by separating the transition point in the transverse motion from that of the longitudinal motion. The transverse transition at a rather low-energy range decreases the effects of space-charge, while the longitudinal transition at a rather high-energy range decreases the effects of nonlinear problems related to acceleration in the ACS. Coupled envelope equations and equipartitioning theory are used for the focusing design. The adoption of the SDTL structure improves both the effective shunt impedance and difficulties in fabricating drift tubes with focusing magnets. An accurate beam-simulation code on a parallel supercomputer was used for confirming any beam-loss problem during acceleration. (author)

  9. AVERAGE REACTION CROSS-SECTIONS FOR 74-MEV TO 112-MEV ALPHA-PARTICLES ON I-127 AND CS-133

    WARNER, RE; WILSCHUT, HW; RULLA, WF; FELDER, GN

    1991-01-01

    The average reaction cross section for 74- to 112-MeV alpha particles on I-127 and Cs-133 was measured by a new method using a magnetic spectrograph and a CsI scintillation detector. The result, sigma-R = 2220+/-50 mb, is in good agreement with optical model calculations and finite-range microscopic

  10. Crab Nebula observations - 0.2-10 MeV

    Gruber, D. E.

    1975-01-01

    Observations of the total emission from the Crab Nebula and also of the pulsed component were made over the 0.2 to 10-MeV range during three balloon flights in 1971 with an actively-collimated NaI scintillator. The total emission flux was positively observed over the entire interval. The observed spectrum to 1 MeV agrees with an extrapolation of the E to the -2.2 power law, which fits lower-energy data. The observations above 1 MeV are factors of 3 and 20 above this law and are better fit with a spectral index of 0.8. Confidence levels are 3 sigma or better for each half-decade band. The three observations are consistent with a constant flux level. The NP 0532 flux, detected during one flight only (August 8) between 0.2 and 0.38 MeV, agrees with the exponential power law spectrum already determined from other observations. The possibility of a rapidly rising pulsed emission fraction over the 0.1- to 1-MeV interval is excluded by this observation.

  11. THE ZR-90(N, P)Y-90 REACTION AT E(N) = 98 MEV

    CONDE, H; OLSSON, N; RAMSTROM, E; RONNQVIST, T; ZORRO, R; BLOMGREN, J; HAKANSSON, A; TIBELL, G; JONSSON, O; NILSSON, L; RENBERG, PU; OSTERLUND, M; UNKELBACH, W; WAMBACH, J; VANDERWERF, SY; ULLMANN, J; WENDER, SA

    1992-01-01

    Double-differential cross sections of the Zr-90(n, p) reaction have been measured at 98 MeV in the angular range 0-degrees-30-degrees for excitation energies up to 40 MeV. The spectra have been interpreted in terms of direct and multistep reactions. The contributions from the latter have been calcul

  12. Elastic and inelastic scattering of 30 MeV and 180 MeV antiprotons on nuclei

    This thesis reports on the first measurements of angular distributions for elastic and inelastic scattering of antiprotons from nuclei, which have been performed, using the beam delivered by LEAR and the spectrometer SPES II, over a wide angular range and with good precision. Angular distributions for elastic scattering of 50 MeV antiprotons from 12C, 40Ca, 208Pb and 180 MeV antiprotons from 12C, 16O, 18O, 40Ca, 208Pb have been measured. Data on the inelastic 4.4 MeV and 9.6 MeV excited states of 12C and 1.98 MeV excited state of 18O have also been collected. The diffractive angular distributions are first analysed in terms of a fuzzy black disk model, which confirms that the antiproton is strongly absorbed (annihilation) by the nuclei. Optical model analysis, with Woods-Saxon geometry, shows that the real potential is attractive and shallow. The potentials are only determined at the nuclear surface, around the strong absorption radius, where /W(R)/ > 2 /V(R)/. Main characteristics of the antip-nucleus elastic scattering cross sections are well described within microscopic models using the free elementary antiN N interaction, like KMT which have no free parameters. Possibility for test of spin-isospin dependence of the elementary amplitude antiN-N from the measurement of unnatural parity states is also studied

  13. Re-measurement of the neutron-induced gamma-ray production cross sections for iron in the energy range 850 keV less than or equal to E/sub n/ less than or equal to 20. 0 MeV. [Tables

    Chapman, G.T.; Morgan, G.L.; Perey, F.G.

    1976-07-01

    Values of the gamma-ray production cross sections for neutron interactions with iron as reported by previous investigators have differed by as much as a factor of 1.5 or more at neutron energies greater than about 5 MeV. Because of this discrepancy, the measurements were repeated at ORNL using the ORELA as a pulsed source of neutrons with energies between 850 keV and 20 MeV. The data were obtained using a NaI(Tl) gamma-ray spectrometer oriented at an angle of 125/sup 0/ to the incident neutron beam. The sample was positioned in the beam at a distance of 47.35 meters from the neutron source. The resulting data, presented as differential cross sections (d/sup 2/sigma/d..cap omega..dE) for gamma rays between 0.7 and 10.5 MeV, show good agreement with some previously published data, but are significantly different from previous ORNL measurements for neutron energies greater than 5 MeV.

  14. Valine radiolysis by MeV ions

    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

  15. Scanning magnet power supply for 10 MeV linac

    The 10 MeV/10 kW RF Linac, coming up at Radiation Processing Facility, Indore; requires a variable frequency and variable amplitude saw-tooth current source for its scanning magnet. In this paper, development of a power supply, which is capable of generating a bipolar saw-tooth current wave up to ±10 A at a frequency, ranging from 0.5 Hz to 50 Hz, is presented. (author)

  16. Radiation effects on MOS and bipolar devices by 8 MeV protons, 60 MeV Br ions and 1 MeV electrons

    The radiation effects of the metal-oxide-semiconductor (MOS) and the bipolar devices are characterised using 8 MeV protons, 60 MeV Br ions and 1 MeV electrons. Key parameters are measured in-situ and compared for the devices. The ionising and nonionising energy losses of incident particles are calculated using the Geant4 and the stopping and range of ions in matter code. The results of the experiment and energy loss calculation for different particles show that different incident particles may give different contributions to MOS and bipolar devices. The irradiation particles, which cause a larger displacement dose within the same chip depth of bipolar devices at a given total dose, would generate more severe damage to the voltage parameters of the bipolar devices. On the contrary, the irradiation particles, which cause larger ionising damage in the gate oxide, would generate more severe damage to MOS devices. In this investigation, we attempt to analyse the sensitivity to radiation damage of the different parameter of the MOS and bipolar devices by comparing the irradiation experimental data and the calculated results using Geant4 and SRIM code. (condensed matter: structure, thermal and mechanical properties)

  17. Study on Beam Steering in the PEFP 20 MeV DTL

    The Proton Engineering Frontier Project (PEFP) is developing a proton linac which accelerate 20 mA proton beams up to 100 MeV. The accelerator consists of an ion source, a low energy beam transport (LEBT), a 3 MeV radio-frequency quadrupole (RFQ), a 100 MeV drift-tube linac (DTL). The DTL structure divides into two parts. One is a DTL (called DTL1) whose energy range is from 3 MeV to 20 MeV. It is designed to operate with 24% beam duty. The other is another DTL (called DTL2) for 20 ∼ 100 MeV with 8% beam duty. There is a MEBT between two DTL structures which will be operated with different beam duties. The main purposes of the MEBT are extracting 20 MeV proton beams to the user group and matching proton beams into the DTL2. This brief report related to the steering properties of the PEFP DTL tanks. For the beam dynamics study related with the steering magnets, we concentrated on the displacement error of the 20 MeV DTL tanks which consists of 4 tanks

  18. Production of the omega meson in the pd --> 3He omega reaction at 1450 MeV and 1360 MeV

    Schonning, K; Bashkanov, M; Berlowski, M; Bogoslawsky, D; Calén, H; Clement, H; Demirors, L; Ekström, C; Fransson, K; Geren, L; Gustafsson, L; Höistad, B; Ivanov, G; Jacewicz, M; Jiganov, E; Johansson, T; Keleta, S; Khakimova, O; Khemchandani, K P; Kren, F; Kullander, Sven; Kupsc, A; Kuzmin, A; Lindberg, K; Marciniewski, P; Morosov, B; Oelert, W; Pauly, C; Petren, H; Petukhov, Yu P; Povtorejko, A; Ruber, R J M Y; Scobel, W; Shafigullin, R; Shwartz, B; Skorodko, T; Sopov, V; Stepaniak, J; Tegner, P -E; Engblom, P Thorngren; Tikhomirov, V; Turowiecki, A; Wagner, G J; Wilkin, C; Wolke, M; Zabierowski, J; Zartova, I; Zlomanczuk, Yu

    2009-01-01

    The production of $\\omega$ mesons in the $pd \\to{}^3$He$ \\omega$ reaction has been studied at two energies near the kinematic threshold, $T_p=1450$ MeV and $T_p=1360$ MeV. The differential cross section was measured as a function of the $\\omega$ cm angle at both energies over the whole angular range. Whereas the results at 1360 MeV are consistent with isotropy, strong rises are observed near both the forward and backward directions at 1450 MeV. Calculations made using a two-step model with an intermediate pion fail to reproduce the shapes of the measured angular distributions and also underestimate the total cross sections.

  19. The Karlsruhe Neutron Transmission Experiment (KANT): Spherical shell transmission measurements with 14 MeV neutrons on beryllium

    This is a set of viewgraphs (no additional text) of a presentation on spherical shell transmission measurements with 14 MeV neutrons on beryllium; the cross for 9Be(n,2n)2α for the energy range between threshold (1.85 MeV) and 20 MeV neutron energy is measured and the measurement is compared with the literature. Also, neutron leakage multiplication in spherical Be shells with various thicknesses are presented. Figs, tabs

  20. 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

    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.

  1. Two body photodisintegration of the deuteron from 100 to 800 MeV

    The total and the differential cross sections for the D(γ,p)n reaction have been measured over the photon energy range 100-800 MeV at the 855 MeV MAMI Microtron in Mainz. The data are presented in the form of thirty-five angular distributions at c.m. proton angles between 30 deg-160 deg in 10 deg intervals and at photon energies in steps of 20 MeV. Previous experimental work is reassessed in the light of the present results and the results compared with some recent theoretical calculations. (author)

  2. Measurement of 14 MeV Neutron Spectrum with Threshold Detectors

    The neutron spectrum of 14 MeV neutron from 'J-25' 150 keV/2.5 neutron generator has been measured for seven different reactions, with threshold energies in the range 3.75-13.00 MeV, by multiple-foil activation technique. The measured activation rates were unfolded with the modified SAND II code. The result was compared with one from TOF measurement at Chiang Mai University

  3. Low energy pion production by 400 to 500 MeV protons

    Using TRIUMF proton beams of 400- to 500-MeV bombarding carbon and copper targets we have measured positive pion production cross sections for pion energies 20 to 100 MeV and pion angles 60 to 1500. The pions were stopped in a range telescope in which time-of-flight, energy loss, and the detection of the pion decay were used for particle identification

  4. The Pb-208(n,p)Tl-208 reaction at E-n=97 MeV

    Ringbom, A; Hakansson, A; Tibell, G; Zorro, R; Blomgren, J; Conde, H; Rahm, J; Olsson, N; Ramstrom, E; Ronnqvist, T; Jonsson, O; Nilsson, L; Renberg, PU; vanderWerf, SY; Lenske, H

    1997-01-01

    Double-differential cross sections of the Pb-208(n,p) reaction have been measured at 97 MeV in the angular range 0 degrees-30 degrees for excitation energies up to 40 MeV. The experimental proton spectra have been compared with calculated spectra obtained with a statistical multistep direct reaction

  5. Measurement of neutron yield by 62 MeV proton beam on a thick Beryllium target

    Osipenko, M; Alba, R; Ricco, G; 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; Schillaci, M; Scuderi, V; Viberti, C M

    2013-01-01

    The design of a low-power prototype of neutron amplifier recently proposed within the INFN-E project indicated the need for more accurate called for detailed 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 degrees 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 $^3$He detector was used. The obtained data are in good agreement with previous measurements at 0 degree with 66 MeV proton beam, covering neutron energies >10 MeV, as well as with measurements at few selected angles with 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 measu...

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

    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 >10MeV, 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

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

    Osipenko, M., E-mail: osipenko@ge.infn.it [INFN, sezione di Genova, 16146 Genova (Italy); Ripani, M. [INFN, sezione di Genova, 16146 Genova (Italy); Alba, R. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Ricco, G. [INFN, sezione di Genova, 16146 Genova (Italy); Schillaci, M. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Barbagallo, M. [INFN, sezione di Bari, 70126 Bari (Italy); Boccaccio, P. [INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Celentano, A. [Dipartimento di Fisica dell' Università di Genova, 16146 Genova (Italy); Colonna, N. [INFN, sezione di Bari, 70126 Bari (Italy); Cosentino, L.; Del Zoppo, A.; Di Pietro, A. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Esposito, J. [INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Figuera, P.; Finocchiaro, P. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Kostyukov, A. [Moscow State University, Moscow 119992 (Russian Federation); Maiolino, C.; Santonocito, D.; Scuderi, V. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Viberti, C.M. [Dipartimento di Fisica dell' Università di Genova, 16146 Genova (Italy)

    2013-09-21

    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 {sup 3}He detector was used. The obtained data are in good agreement with previous measurements at 0° using 66 MeV proton beam, covering neutron energies >10MeV, 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.

  8. <600> MeV synchro-cyclotron

    1971-01-01

    One of the 14 pancakes of the new magnet coils for the 600 MeV synchro-cyclotron which were wound and coated with epoxy resin on the CERN site. These new coils will replace the present ones which have been in use for more than 14 years but are now showing signs of deteriorations.

  9. Attenuation of 10 MeV electron beam energy to achieve low doses does not affect Salmonella spp. inactivation kinetics

    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. - Highlights: • 10 MeV eBeam energy was attenuated to 2.9±0.22 MeV using HDPE sheets. • Attenuation of eBeam energy does not affect the inactivation kinetics of Salmonella. • Microbial inactivation is independent of eBeam energy in the range of 3–10 MeV

  10. Measurement of (n,Xn) reaction cross sections at 96 MeV; Measure des sections efficaces (n,Xn) a 96 MeV

    Sagrado Garcia, Melle Inmaculada C. [Ecole Doctorale: SINEM, U.F.R. de Sciences, Universite de Caen/Basse-Normandie, Esplanade Paix14000 Caen (France)

    2006-10-15

    Nucleon induced reactions in the 20-200 MeV energy range are intensively studied since a long time. The evaporation and the pre-equilibrium processes correspond to an important contribution of the production cross section in these reactions. Several theoretical approaches have been proposed and their predictions must be tested. The experimental results shown in this work are the only complete set of data for the (n,Xn) reactions in this energy range. Neutron double differential cross section measurements using lead and iron targets for an incident neutron beam at 96 MeV were carried out at TSL Laboratory in Uppsala, Sweden. The measurements have been performed for the first time with an energy threshold of 2 MeV and for a wide angular range (15 angle - 98 angle). Neutrons have been detected using two independent setups, DECOI and DEMON and CLODIA and SCANDAL, in order to cover the whole energy range (2-100) MeV. The angular distributions, the differential cross sections and the total inelastic production cross sections have been calculated using the double differential cross sections. The comparison between the experimental data and the predictions given by two of the most popular simulation codes, GEANT3 and MCNPX, have been performed, as well as the comparison with the predictions of the microscopic simulation model DYWAN, selected for its treatment of nucleon-nucleon reactions. (author)

  11. Calorimetry for absorbed dose measurement at 1-4 MeV electron accelerators

    Calorimeters are used for dose measurement, calibration and intercomparisons at industrial electron accelerators, and their use at 10 MeV electron accelerators is well documented. The work under this research agreement concerns development of calorimeters for use at electron accelerators with energies in the range of 2-4 MeV. The dose range of the calorimeters is 3-40 kGy, and their temperature stability after irradiation was found to be sufficient for practical use in an industrial environment. Measurement uncertainties were determined to be 5% at k = 2. (author)

  12. Thermoluminescence response of Ge-, Al- and Nd- doped optical fibers by 6 MeV - electron and 6 MeV - photon irradiations

    In this paper, we report the prediction of thermoluminescence responses of Neodymium-doped SiO2 optical fibre with various dose ranges from 0.5 Gy to 4.0 Gy by 6 MeV - electron irradiations without requirement for experimental measurements. A technique has been developed to calculate prediction of 6 MeV - electron response of Neodymium-doped SiO2 optical fibre by observing the measured TL response of 6 MV - photon and the ratio of known measured photon/electron yield ratio distribution for Ge-doped, Al-doped optical fibre and standard TLD 100 dosimeter. The samples were kept in gelatin capsule an irradiated with 6 MV - photon at the dose range from 0.5 Gy to 4.0 Gy. Siemens model Primus 3368 linear accelerator located at Hospital Sultan Ismail, Johor Bahru has been used to deliver the photon beam to the samples. We found the average response ratio of 6 MV - photon and 6 MeV - electron in Ge-doped, Al-doped optical fibre and standard TLD-100 dosimeter are 0.83(3). Observing the measured value of 6 MV - photon irradiation this average ratio is useful to find the prediction of thermoluminescence responses by 6 MeV - electron irradiation of Neodymium-doped SiO2 optical fibre by the requirement for experimental measurements with various dose ranges from 0.5 Gy to 4.0 Gy by 6 MV - photon irradiations.

  13. 14 MeV proton activation analysis

    A fast nuclear nondestructive method for protein analysis using the 14 MeV proton activation has been developed. The total nitrogen content was measured through the reaction: 14N (p,n) 14O, (Tsub(1/2)=71 s). The 14O activity was detected by means of its characteristic 2.312 MeV gamma-ray line with a NaI(Tl) detector. For a fast determination of a large number of samples a mechanized sistem reacting a rate of one sample per minute has been developed. The laboratory electronics comprises a multichannel analyser, a PDP computer and an electronic module comtroller. Comparison of the results obtained by the method described and the classical Kjeldal technique for samples of various cereal grains (soya bean seads, wheat, barley and corn) showed good correlation. A problem of the analysis of the whole protein region on corn and soya-bean seads, where this region is thicker (0,2 - 2 mm), is mentioned. In this case flour was proposed to be used to obtain a protein homogeneous sample and the irradiaton dose for a sample was about 33,000 Gy, mainly (99%) from protons (27 s x 100 nA x 14 MeV)

  14. Radiation chemical investigations of Fricke solution using 30 MeV alpha beam from cyclotron

    Systematic investigations on the radiolysis of liquid systems using 30 MeV alpha beam from cyclotron at the Variable Energy Cyclotron Centre (VECC) have been initiated. A liquid target assembly incorporating current measurement devices in solution as well as on the target assembly window has been designed. Suitable aluminium absorbers of different thickness have been used to extract different energies of alpha ranging from 24.82 MeV to 6.41 MeV corresponding to the LET range of 2.77 eV/A0 to 7.98 eV/A0. A fricke solution using 10 mM Fe2+ in 0.8 NH2SO4 in presence of 5mM NaCl under continuous oxygen bubbling has been radiolysed with radiation of different LET. The effect of LET on the G(Fe3+) has been investigated and the results are discussed. (author)

  15. DC Electron Accelerators - a perspective on 3 MeV DC accelerator at EBC

    Electron beam accelerators are finding wide ranging applications like surface curing of coatings, cross-linking polymeric materials, sterilization of medical products, coloration of diamonds, disinfection and preservation of food products, purification of industrial and biological waste etc. Electron beam energy and dose rate for different application differs widely depending upon the type of product and the desired modification. The beam energy and dose rate requirement for these types of applications ranges between 0.15 MeV to 10 MeV and few kilowatt to hundreds of kilowatts. Electrostatic accelerators (direct current type) are suitable option for large throughput, high electrical efficiency for the above applications. In view of the growing needs we have taken up indigenous development of industrial accelerators at APPD, BARC. A machine rated for 3 MeV, 30 kW beam power is in the trial operations at Electron Beam Centre, Kharghar, Navi Mumbai. The 3 MV DC supply for this based on a parallel fed voltage multiplier scheme considering power efficiency, energy stability and reliability. The accelerator is designed to operate with beam energies from 1 MeV to 3 MeV with beam current of 0-10 mA

  16. Shielding measurements for a 230 MeV proton beam

    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 cm3 to 1000 cm3 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

  17. The measurement of (n,2n) cross section for 23Na at 13.3 to 18.5 MeV

    The (n,2n) cross-section for 23Na has been measured by the activation method in the energy range 13.3 to 18.5 MeV. Monoenergitic neutrons were obtained from T(d,n)4He reaction with 2.3 MeV deuteron energy. The induced specific activities were detected by a coincidence counting setup. For comparison existed data and theoretical calculation from 12∼20 MeV are also given

  18. Measurement of neutron-induced fission cross-sections of Th232, U238, U233 and Np237 relative to U235 from 1 MeV to 200 MeV

    Shcherbakov, O.A.; Laptev, A.B.; Petrov, G.A. [Petersburg Nuclear Physics Inst., Gatchina, Leningrad district (Russian Federation); Fomichev, A.V.; Donets, A.Y.; Osetrov, O.I.

    1998-11-01

    The measurements of neutron-induced cross-section ratios for Th232, U238, U233 and Np237 relative to U235 have been carried out in the energy range from 1 MeV up to 200 MeV using the neutron time-of-flight spectrometer GNEIS based on 1 GeV proton synchrocyclotron. Below 20 MeV, the results of present measurements are roughly in agreement with evaluated data though there are some discrepances to be resolved. (author)

  19. The scattering of polarized deuterons on 3He between 10 and 17 MeV

    Using the LASL polarized beam facility, the cross section and vector and tensor analysing powers for the 3He(d vector,d)3He and 3He(d vector,p)4He reactions have been measured in a large angular range at energies between 10 and 17 MeV. (orig./WL)

  20. Neutron scattering and reactions on 59Co from 1 to 20 MeV

    The paper presents a complete analysis of all the interactions of neutrons with 59Co in the energy range 1-20 meV, excluding the resonance region at very low energies. Optical model calculations, compound nucleus calculations and Weisskopf-Ewing calculations are given. (U.K.)

  1. Energy dissipation of 0.6 and 0.8MeV electrons in elemental materials

    The spatial distributions of energy dissipation of electrons in Be, Al, Cu and Ag were obtained experimentally for well collimated electron beams of 0.6 and 0.8 MeV. Experimental results of the present work join smoothly to the previous ones of 1.0 MeV to 2.0 MeV electrons. Comparing with Spencer theory, it is found that our experiment and theory are generally in agreement except in shallow penetration depth. The extrapolated range values of the present work join also smoothly in the atomic number curves of previous ones. (author)

  2. Spectrum of neutrons emitted from a thick beryllium target bombarded with 7 MeV deuterons

    The spectrum of neutrons emitted from a thick beryllium target bombarded with 7 MeV deuterons is measured at 25 reaction angles distributed between 00 and 1580, and over the neutron energy range ≅11.0 MeV. The spectrum is determined relative to the standard 252Cf prompt-fission-neutron-spectrum using fast time-of-flight techniques. The results are presented as angle-energy differential distributions and as relative numerical group cross sections suitable for establishing a reference field for applied studies. 24 refs., 4 figs

  3. Performance of the compact 300 MeV electron ring JSR

    Yokomizo, H.; Yanagida, K.; Harada, S.; Mashiko, K.; Yokoyama, M.; Hashimoto, H.; Nakayama, K.; Kabasawa, M.; Harami, T.; Suzuki, Y.

    1990-05-01

    A compact ring, JSR, has been constructed in a short period of 15 months. The magnets, vacuum chamber and rf system are well manufactured, coming up to the design expectation. The good-field region {ΔB}/{B} JSR at a maximum energy of 300 MeV. The lifetime of the stored electrons is ˜ 30 min, which is mainly determined by collisions with the residual gas in the vacuum chamber. JSR has proved to work correctly in the storage and acceleration of electrons within an energy range from 150 to 300 MeV.

  4. Intensity maps of MeV electrons and protons below the radiation belt

    The global distributions of energetic electrons (0.19 - 3.2 MeV) and protons (0.64 - 35 MeV) are shown in the form of contour maps. The data were obtained by two sets of energetic particle telescopes on board the satellite OHZORA. The observed altitude range is 350 - 850 Km. Ten degress meshes in longitude and latitude were used to obtain the intensity contours. A pitch angle distribution of J(α) = J(90). sinnα with n = 5A is assumed to get the average intensity in each mesh. (author)

  5. Design of the MYRRHA 17-600 MeV Superconducting Linac

    Biarrotte, J-L; Bouly, F; Carneiro, J-P; Vandeplassche, D

    2013-01-01

    The goal of the MYRRHA project is to demonstrate the technical feasibility of transmutation in a 100MWth Accelerator Driven System (ADS) by building a new flexible irradiation complex in Mol (Belgium). The MYRRHA facility requires a 600 MeV accelerator delivering a maximum proton flux of 4 mA in continuous operation, with an additional requirement for exceptional reliability. This paper will briefly describe the beam dynamics design of the main superconducting linac section which covers the 17 to 600 MeV energy range and requires enhanced fault-tolerance capabilities.

  6. New techniques in neutron data measurements above 30 MeV

    Recent developments in experimental facilities have enabled new techniques for measurements of neutron interactions above 30 MeV. Foremost is the development of both monoenergetic and continuous neutron sources using accelerators in the medium energy region between 100 and 800 MeV. Measurements of the reaction products have been advanced by the continuous improvement in detector systems, electronics and computers. Corresponding developments in particle transport codes and in the theory of nuclear reactions at these energies have allowed more precise design of neutron sources, experimental shielding and detector response. As a result of these improvements, many new measurements are possible and the data base in this energy range is expanding quickly

  7. Neutron response matrix for unfolding NE-213 measurements to 21 MeV

    A neutron response matrix from measured neutron responses of NE-213 in the energy range of 0.2 to 22 MeV is presented. An interpolation scheme was used to construct an 81-column matrix from the data of Verbinski, Burrus, Love, Zobel, and Hill. As a test of the new response matrix, the Cf-252 neutron spectrum was measured and unfolded using the new response matrix and the FORIST unfolding code. The spectrum agrees well with previous measurements at lower energies, while providing new information above 8 MeV

  8. Number transmission of 0.6 and 0.8MeV electrons in elemental materials

    The number transmissions of electrons in Be, Al, Cu and Ag were obtained experimentally for well collimated electron beams of 0.6 and 0.8 MeV. Experimental results of the present work join smoothly to the previous ones of 1.0 MeV to 2.0 MeV electrons. The ratios of extrapolated range Rsub(ex) to true range R0 give generally minimum values near 1 MeV (approximately 2mc2) as well as the stopping power. An investigation was done for empirical equation of the form eta=exp(-xP/CEsup(m)), where E is the incident electron energy, x, penetration depth, and p, C and m are the parameters determined from experimental data. (author)

  9. ETAII 6 MEV PEPPERPOT EMITTANCE MEASUREMENT

    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. Proton scattering from 4He at 500 MeV

    We calculate the optical potential for the scattering of 500 MeV protons from 4He using first-order Brueckner theory and compare with experimental data. The real part of the calculated potential has a 'wine bottle' shape in agreement with recent phenomenological analyses. The agreement with experiment is good for scattering angles less than 700. We also analyse the same data using the Dirac equation. The fits to the data over a wide angular range are very good. We find ambiguities in the relativistic potentials as several sets of parameters fit the data almost equally well. In all cases the real vector and scalar potentials exhibit central minima. The 'Schroedinger equivalent' potentials again have 'wine bottle' shapes. We discuss the similarities between the two approaches. (orig.)

  11. Proton polarimeter calibration between 82 and 217 MeV

    The proton analyzing power in carbon has been measured for energies of 82-217 MeV and proton scattering angles of 5-410. The measurements were carried out using polarized protons from the elastic scattering 1H(e→,p→) reaction and the Focal Plane Polarimeter (FPP) in Hall A of Jefferson Lab. A new parameterization of the FPP p-C analyzing power was fit to the data, which is in good agreement with previous parameterizations and provides an extension to lower energies and larger angles. The main conclusions are that all polarimeters to date give consistent measurements of the carbon analyzing power, independently of the details of their construction and that measuring on a larger angular range significantly improves the polarimeter figure of merit at low energies.

  12. Proton Polarimeter Calibration between 82 and 217 MeV

    Glister, J; Lee, B; Beck, A; Brash, E; Camsonne, A; Choi, S; Dumas, J; Feuerbach, R; Gilman, R; Higinbotham, D W; Jiang, X; Jones, M K; May-Tal Beck, S; McCullough, E; Paolone, M; Piasetzky, E; Roche, J; Rousseau, Y; Sarty, A J; Sawatzky, B

    2009-07-01

    The proton analyzing power in carbon has been measured for energies of 82 to 217 MeV and proton scattering angles of 5 to 41 degrees. The measurements were carried out using polarized protons from the elastic scattering H(pol. e, pol. p) reaction and the Focal Plane Polarimeter (FPP) in Hall A of Jefferson Lab. A new parameterization of the FPP p-C analyzing power was fit to the data, which is in good agreement with previous parameterizations and provides an extension to lower energies and larger angles. The main conclusions are that all polarimeters to date give consistent measurements of the carbon analyzing power, independently of the details of their construction and that measuring on a larger angular range significantly improves the polarimeter figure of merit at low energies.

  13. Proton polarimeter calibration between 82 and 217 MeV

    Glister, J. [Department of Astronomy and Physics, Saint Mary' s University, Halifax, Nova Scotia, B3H 3C3 (Canada); Dalhousie University, Halifax, Nova Scotia, B3H 3J5 (Canada)], E-mail: jglister@jlab.org; Ron, G. [Tel Aviv University, Tel Aviv 69978 (Israel); Lee, B. [Seoul National University, Seoul 151-747 (Korea, Republic of); Beck, A. [NRCN, P.O. Box 9001, Beer-Sheva 84190 (Israel); Brash, E. [Christopher Newport University, Newport News, VA 23606 (United States); Camsonne, A. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Choi, S. [Seoul National University, Seoul 151-747 (Korea, Republic of); Dumas, J. [Rutgers, State University of New Jersey, Piscataway, NJ 08855 (United States); Feuerbach, R. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Gilman, R. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Rutgers, State University of New Jersey, Piscataway, NJ 08855 (United States); Higinbotham, D.W. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Jiang, X. [Rutgers, State University of New Jersey, Piscataway, NJ 08855 (United States); Jones, M.K. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); May-Tal Beck, S. [NRCN, P.O. Box 9001, Beer-Sheva 84190 (Israel); McCullough, E. [Department of Astronomy and Physics, Saint Mary' s University, Halifax, Nova Scotia, B3H 3C3 (Canada); Paolone, M. [University of South Carolina, Columbia, SC 29208 (United States); Piasetzky, E. [Tel Aviv University, Tel Aviv 69978 (Israel); Roche, J. [Ohio University, Athens, OH 45701 (United States); Rousseau, Y. [Rutgers, The State University of New Jersey, Piscataway, NJ 08855 (United States); Sarty, A.J. [Department of Astronomy and Physics, Saint Mary' s University, Halifax, Nova Scotia, B3H 3C3 (Canada)] (and others)

    2009-07-21

    The proton analyzing power in carbon has been measured for energies of 82-217 MeV and proton scattering angles of 5-41{sup 0}. The measurements were carried out using polarized protons from the elastic scattering {sup 1}H(e{sup {yields}},p{sup {yields}}) reaction and the Focal Plane Polarimeter (FPP) in Hall A of Jefferson Lab. A new parameterization of the FPP p-C analyzing power was fit to the data, which is in good agreement with previous parameterizations and provides an extension to lower energies and larger angles. The main conclusions are that all polarimeters to date give consistent measurements of the carbon analyzing power, independently of the details of their construction and that measuring on a larger angular range significantly improves the polarimeter figure of merit at low energies.

  14. Study of calf thymus DNA irradiated in vitro with MeV fluorine ions

    A study of the fragments of DNA irradiated with MeV ions is important for the understanding of the DNA damage mechanism and the subsequent biological effects (induced by heavy ions). In this experiment, the products of calf thymus DNA (CT DNA) irradiated with MeV fluorine ions were analyzed using agarose gel electrophoresis, modified time-of-flight mass spectrometer (MALDI-TOF), and high-performance liquid chromatography (HPLC). The results showed that the molecular mass of the fragments were concentrated around 831 bp with agarose gel electrophoresis, there was no observable product in the range of 1,000-30,000 (m/q) using MALDI-TOF, and small biomolecules were separated from the products. The results of this study indicated that the strand breaks of calf thymus DNA induced by MeV fluorine ions were nonrandom. (authors)

  15. Extrapolated neutron activation cross sections for dosimetry to 44 MeV

    Thirty-one neutron activation cross sections have been extrapolated to 44 MeV for dosimetry applications at high-energy, accelerator-based neutron sources. All cross sections have undergone integral testing in Be(d,n) fields at E/sub d/ = 14, 16, and 40 MeV. The integral activities for most of the reactions agree within 10% with calculations based on time-of-flight measurements of the flux spectra. Tests show that at least 25 of the cross sections can be used with the SAND II code to unfold neutron spectra with differential errors of 10 to 30% in the neutron energy range from 2 to 30 MeV

  16. Performance of the compact 300 MeV electron ring JSR

    A compact ring, JSR, has been constructed in a short period of 15 months. The magnets, vacuum chamber and rf system are well manufactured, coming up to the design expectation. The good-field region ΔB/B-4 extends over ±45 mm in the dipole magnets. The base pressure has reached 3x10-10 Torr at the pump head. An electron beam was successfully injected from a linac at an energy of ∝150 MeV, and electrons were smoothly accelerated and stored in JSR at a maximum energy of 300 MeV. The lifetime of the stored electrons is ∝30 min, which is mainly determined by collisions with the residual gas in the vacuum chamber. JSR has proved to work correctly in the storage and acceleration of electrons within an energy range from 150 to 300 MeV. (orig.)

  17. Dispersive spherical optical model of neutron scattering from Al27 up to 250 MeV

    Molina, A; Quesada, J M; Lozano, M

    2002-01-01

    A spherical optical model potential (OMP) containing a dispersive term is used to fit the available experimental database of angular distribution and total cross section data for n + Al27 covering the energy range 0.1- 250 MeV using relativistic kinematics and a relativistic extension of the Schroedinger equation. A dispersive OMP with parameters that show a smooth energy dependence and energy independent geometry are determined from fits to the entire data set. A very good overall agreement between experimental data and predictions is achieved up to 150 MeV. Inclusion of nonlocality effects in the absorptive volume potential allows to achieve an excellent agreement up to 250 MeV.

  18. Telescope for studying charged particles produced by 14 MeV neutrons

    We have developed a telescope using semi-conductor detectors for studying the charged particles produced in a thin radiator by 14 MeV neutrons. It consists of a proportional CO2-counter and two cooled semiconductor detectors (one of the ΔE/ΔX type, the other of the E type). This low-noise telescope has good energy resolution (370 keV). Used in conjunction with a bi-parametric recording (ΔE - E) it gives a satisfactory identification and discrimination of the charged particles (p,d) detected. This telescope has been used to observe the spectrum of protons from the reaction D(n,p)2n emitted at 0 deg. (En 13.9 MeV) in the energy range 4 - 14 MeV. (author)

  19. Study of calf thymus DNA irradiated in vitro with MeV fluorine ions

    2006-01-01

    A study of the fragments of DNA irradiated with MeV ions is important for the understanding of the DNA damage mechanism and the subsequent biological effects (induced by heavy ions). In this experiment, the products of calf thymus DNA (CT DNA) irradiated with MeV fluorine ions were analyzed using agarose gel electrophoresis,modified time-of-flight mass spectrometer (MALDI-TOF), and high-performance liquid chromatography (HPLC).The results showed that the molecular mass of the fragments were concentrated around 831 bp with agarose gel electrophoresis, there was no observable product in the range of 1,000- 30,000 (m/q) using MALDI-TOF, and small biomolecules were separated from the products. The results of this study indicated that the strand breaks of calf thymus DNA induced by MeV fluorine ions were nonrandom.

  20. Relativistic analysis of nuclear ground state densities at 135 to 200 MeV

    M A Suhail; N Neeloffer; Z A Khan

    2005-12-01

    A relativistic analysis of p + 40Ca elastic scattering with different nuclear ground state target densities at 135 to 200 MeV is presented in this paper. It is found that the IGO densities are more consistent in reproducing the data over the energy range considered here. The reproduction of spin-rotation-function data with the simultaneous fitting of differential cross-section and analyzing power, and the appearance of wine-bottle-bottom shaped Re eff() in the transition energy region, sensitively depends on the input nuclear ground state densities and are not solely the relativistic characteristic signatures. We also found that the wine-bottle-bottom shaped Re eff() is preferred by the spin observables in the transition energy region (i.e. 181 MeV to 200 MeV).

  1. Neutron total and scattering cross sections of 6Li in the few MeV region

    Neutron total cross sections of 6Li are measured from approx. 0.5 to approx. 4.8 MeV at intervals of 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;α)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

  2. Measurements of neutron spectra from iron and boron—in—polyethylene bomareded with 14MeV nuetrons

    ZhouYu-Qing; ChenYuan; 等

    1997-01-01

    The leakage spectra of 14MeV neutrons from spheres of iron and boron-inpolyethylene with three differnet mass ratios of boron carbide to polyethylene were measured over the energy range of 20 keV to 16MeV by using proton recoil method.The integral leakages and removal cross sections at different lower cut-off energy were given.

  3. Study of the gamma spectra emitted in a nuclear reaction - Measurement of the half-lives of the levels 6.13 MeV, 6.92 MeV and 7.12 MeV of 16O

    When the energy shifts of the gamma spectrum released during a nuclear reaction are important compared with the detector resolution, the comparison of the experimental spectrum with theoretical spectra allows us to determine the half-life of the initial state of the transition. The calculation of the experimental spectrum implies to know the slowing-down of the recoil nucleus in the matter in order to take into account the Doppler effect. For recoil energies in the range of the MeV and for solid media, the Lindhard theory agrees well with experimental data. The phenomenon of deflection which appears at very low energies must be taken into account by restraining the measurement domain. By choosing an adequate media we can measure half-lives in the domain 1 and 100 fs without needing to take into account deflection effects. We have measured the half-life of the first 3 energy levels of 16O (6.135 MeV, 6.923 MeV and 7.121 MeV), these levels are reached through the reaction 19F(p,αγ)16O with proton incident energies ranging from 0.872 MeV to 2.42 MeV. We have used a coaxial germanium semi-conductor with lithium additions that was connected to an amplification line of Ortec type. 2 kinds of target have been used: calcium fluoride and copper fluoride evaporated on tantalum support. We have obtained the following values for the half-life: (16±4) fs for the 6.923 MeV level, (18±4) fs for the 7.121 MeV level, and for the 6.135 MeV we can only give a lower limit since the gamma decay occurs when the nucleus is at rest τ > 200 fs

  4. Underwater Ranging

    S. P. Gaba

    1984-01-01

    Full Text Available The paper deals with underwater laser ranging system, its principle of operation and maximum depth capability. The sources of external noise and methods to improve signal-to-noise ratio are also discussed.

  5. Demonstration of multilayer reflective optics at photon energies above 0.6 MeV

    Brejnholt, Nicolai F.; Soufli, Regina; Descalle, Marie-Anne; Fernandez-Perea, Monica; Christensen, Finn Erland; Jakobsen, Anders Clemen; Honkimaeki, Veijo; Pivovaroff, Michael J.

    2014-01-01

    Focusing optics operating in the soft gamma-ray photon energy range can advance a range of scientific and technological applications that benefit from the large improvements in sensitivity and resolution that true imaging provides. An enabling technology to this end is multilayer coatings. We show that very short period multilayer coatings deposited on super-polished substrates operate efficiently above 0.6 MeV. These experiments demonstrate that Bragg scattering theory established for multil...

  6. Si exfoliation by MeV proton implantation

    Proton implantation in silicon and subsequent annealing are widely used in the Smart Cut™ technology to transfer thin layers from a substrate to another. The low implantation energy range involved in this process is usually from a few ten to a few hundred of keV, which enables the separation of up to 2 μm thick layers. New applications in the fields of 3D integration and photovoltaic wafer manufacturing raise the demand for extending this technology to higher energy in order to separate thicker layer from a substrate. In this work, we propose to investigate the effect of proton implantation in single crystalline silicon in the 1–3 MeV range which corresponds to a 15–100 μm range for the hydrogen maximum concentration depth. We show that despites a considerably lower hydrogen concentration at Rp, the layer separation is obtained with fluence close to the minimum fluence required for low energy implantation. It appears that the fracture propagation in Si and the resulting surface morphology is affected by the substrate orientation. Defects evolution is investigated with Fourier Transform Infrared Spectroscopy. The two orientations reveal similar type of defects but their evolution under annealing appears to be different.

  7. 14 MeV neutrons physics and applications

    Valkovic, Vladivoj

    2015-01-01

    Despite the often difficult and time-consuming effort of performing experiments with fast (14 MeV) neutrons, these neutrons can offer special insight into nucleus and other materials because of the absence of charge. 14 MeV Neutrons: Physics and Applications explores fast neutrons in basic science and applications to problems in medicine, the environment, and security.Drawing on his more than 50 years of experience working with 14 MeV neutrons, the author focuses on:Sources of 14 MeV neutrons, including laboratory size accelerators, small and sealed tube generators, well logging sealed tube ac

  8. Neutron- and proton-induced evaluated transport library up to 150 MeV

    A new evaluated nuclear data library has been created. The library consists of two sub-libraries for neutron and proton incident particles. The neutron sub-library contains nuclear data for transport, heating and shielding applications for 242 nuclides with atomic numbers ranging from 8 to 82 in the energy region of primary neutrons from 10-5 eV to 150 MeV. Data below 20 MeV are taken mainly from ENDF/B-VI (revision 8) and for some nuclides, from the JENDL-3.3 and JEFF-3.0 libraries. The proton sub-library should contain data for the same range of target nuclides and energies. Proton-induced evaluated cross-section files are available for 15 nuclides at the moment. The evaluation of emitted particle energy and angular distributions at energies above 20 MeV (for incident neutrons) and above the reaction threshold (for incident protons) was performed with the help of the ALICE/ASH code and the analysis of available experimental data. The total cross-sections, elastic cross-sections and elastic scattering angular distributions were calculated with the help of the coupled channel model. The results of the calculation were adjusted to the data from ENDF/B-VI, JENDL-3.3, or JEFF-3.0 at the neutron energy equal to 20 MeV. The library is written in ENDF-6 format using the MF=3/MT=5 and MF=6/MT=5 representations

  9. Powerful industrial electron accelerators type ILU for energy up to 10 MeV

    The industrial electron accelerators type ILU are developed and produced by the Budker Institute of Nuclear Physics. The ILU accelerators are working in many countries in the industrial lines as well as in some research establishments starting from the beginning of 70-s. These machines are the pulse RF type accelerators with relatively low working frequency - 120 MHz for ILU-6 and ILU-10 and 180 MHz for ILU-8. Their energy range is from 0.8 MeV (ILU-8) to 5 MeV (ILU-10), beam power is up to 50 kW. The ILU machines are working in various technological processes - radiation modification of polymer tubes and films, polymer pipes for hot water supply, wires, cables, sterilization of single use medical products (syringes, hospital and operation gowns, sets for operations, etc.), decontamination of the medicinal raw. The ILU accelerators are very compact machines because they do not need the big high pressure vessel filled with insulating gas. The height of the ILU-10 machine (with energy up to 5 MeV) is less than 3 meters. The ILU-8 machine with energy range 0.8 - 1 MeV can be installed inside the local shield with height of 3.24 m. The local shield can be placed in the ordinary industrial shops. The ILU accelerators are equipped with several beam extraction devices - linear scanner and scanners with 4 windows permitting to organize the irradiation of the long products (tubes, cables, wires, pipes) from 4 sides. The rewinding devices providing the twist-free transportation of the long products in the irradiation zone are also designed and produced by the Institute. The new ILU-14 machine for energy range 7.5 - 10 MeV is under development. This machine is very good for radiation sterilization. (author)

  10. A study of S-wave n-p scattering using a new effective range formula

    The phase shift data from 1 to 500 MeV are studied using a new effective range formula. An excellent fit to data up to 200 MeV is obtained which extrapolates to 500 MeV still reproducing the data with deviations small compared to the size of the error bars. This fit yields a value of the scattering length in agreement with the literature but a value of the effective range that is off. (author)

  11. 10 MeV Medical Cyclotron Prototype Beam Commissioning

    GUAN; Feng-ping; GE; Tao; YIN; Zhi-guo; SONG; Guo-fang; ZHANG; Tian-jue; JI; Bin; LI; Peng-zhan; CAO; Lei; HOU; Shi-gang; LIU; Geng-shou; WANG; Feng; LEI; Yu; WU; Long-cheng; WEN; Li-peng; LI; Zhen-guo; CUI; Tao; JIA; Xian-lu; YAO; Hong-juan; PAN; Gao-feng; ZHANG; Su-ping; CAI; Hong-ru; XIE; Huai-dong

    2012-01-01

    <正>A 10 MeV medical cyclotron prototype for the production of short-lived isotopes has been developed independently at CIAE with a time span of 2 years. On the inner target, 8 hours stability test has been finished. The extraction beam is 10 MeV with a beam intensity of 100 μA.

  12. Dosimetric comparison of 4 MeV and 6 MeV electron beams for total skin irradiation

    In this study, dosimetric aspects of TSEI consisting of a 4 MeV beam with no spoiler were investigated in comparison to a nominal 6 MeV beam with spoiler, and the potential for clinical applications was evaluated. The TSEI technique is based on the Stanford technique, which utilizes a beam configuration of six-dual fields. MOSFETs were used to measure the optimal gantry angle, profile uniformity, and absolute dose at the calibration point. The depth dose curve of the central axis was measured in the treatment plane using EBT2 film. Photon contamination was measured as the dose at 5 cm depth in a solid water phantom relative to the maximum dose using a parallel plate ion chamber. A MOSFET dosimeter placed on the surface of a humanoid phantom, and EBT2 films inserted into a humanoid phantom were used to verify the TSEI commissioning. Dosimetric aspects of the 4 MeV TSEI beam, such as profile uniformity (±10%) and relative photon contamination (<0.001%), were comparable to those of a 6 MeV TSEI beam. The relative depth dose of the 4 MeV electrons was 81.4% at the surface and 100% at 0.4 cm. For the 6 MeV electrons, the relative depth dose was 93.4% at the surface and 100% from 0.2 cm to 0.4 cm. The calculated B-factor of the 4 MeV TSEI beam was 1.55, and 1.53 for the 6 MeV TSEI. 80% of the prescribed dose was obtained at 0.22 cm depth for the 4 MeV TSEI beam and 0.53 cm for the 6 MeV TSEI beam in the humanoid phantom measurement. The suggested 4 MeV beam for TSEI could be applied to shallow depth skin diseases and to electron boost as second treatment course

  13. The experiment 787 high efficiency photon veto detector in the 20 - 300 MEV range

    Experiment E787 is searching for the rare decay K → πνν at the Brookhaven Alternating Gradient Synchrotron (AGS). To suppress the background from the dominant K → ππo branch, a fast lead scintillator sandwich veto assembly system was used. An inefficiency level of ∼ 1 x 10-6 has been achieved for detecting πo. The limitations are in part geometrical in part due to photonuclear interactions. Our present understanding of these limitations will be presented together with our upgrading plans using pure CSI crystals. (author). 7 refs., 4 figs

  14. The reaction π+ + d = 2p in the 300 MeV range

    The inelastic pion deuteron scattering is studied for pion impulses in the centre-of-mass system at 50 to 300 MeV/c and polarization effects in the reaction p + p = π+ + d for the case of polarized protons are analyzed too. A detailed comparison with experiments is given. (author)

  15. Evaluated Nuclear Data Library for Transport Calculations at Energies up to 150 MeV

    A new evaluated nuclear data library has been created. The library consists of two sub-libraries for neutron and proton incident particles. The first version of neutron sub-library has been completed and described in the present paper. The library contains nuclear data for transport, heating, and shielding applications for 242 nuclides ranging in atomic number from 8 to 82 in the energy region of primary neutrons from 10-5 eV to 150 MeV. Data below 20 MeV are taken mainly from ENDF/B-VI (Revision 8) and for some nuclides, from the JENDL-3.3 and JEFF-3.0 libraries. The evaluation of emitted particle energy and angular distributions at the energies above 20 MeV was performed with the help of the ALICE/ASH code and the analysis of available experimental data. The total cross sections, elastic cross sections, and elastic scattering angular distributions were calculated with the help of the coupled channel model. The results of the calculation were adjusted to the data from ENDF/B-VI, JENDL-3.3m or JEFF-3.0 at the neutron energy equal to 20 MeV. The library is written in ENDF/B-VI format using the MF=3/MT=5 and MF=6/MT=5 representations

  16. 3He(t,t)3He elastic scattering measurements from 9 to 17 MeV

    Angular distributions of the analyzing power and differential cross section for 3He(t,t)3He elastic scattering are reported for triton bombarding energies of 9.02, 11.00, 13.02, 15.02, 16.00, and 17.02 MeV, over a c.m. angular range from 25degree to 155degree. Excitation functions for the analyzing power are presented for the energy range 14.42--17.22 MeV. Problems in the phase-shift analysis of the data are discussed

  17. Factors determining the lifetime damage coefficients and the low-frequency noise in MeV proton irradiated silicon diodes

    The impact of several factors, related to the doping density, the substrate type and the thermal pre-treatment on the proton radiation damage coefficients of Si diodes is discussed and verified experimentally. The diode parameters investigated are the leakage current density, the recombination lifetime and the low-frequency noise current spectral density. Proton irradiations have been performed in the energy range 10 MeV to 100 MeV and in the fluence range of 5 x 109 to 4 x 1011 cm-2, typical for space applications. The obtained coefficients are compared with theoretical NIEL predictions. (author)

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

    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.

  19. Grain Boundary Related Effects in Aluminium during 600 MeV Proton Irradiation of Different Temperatures

    Singh, Bachu Narain; Leffers, Torben; Green, W.V.; Victoria, M.

    Samples of high-purity aluminium were irradiated with 600 MeV protons at temperatures in the range 130 to 433°C; in these experiments 615 and 125 appm of hydrogen and helium, respectively, are produced per dpa. Bubble formation and growth at grain boundaries and in the zone adjacent to the bubble......-denuded zone are described. Precipitation at grain boundaries and migration of grain boundaries during irradiation are also reported....

  20. The angular distribution of neutron-proton scattering at 27.3 MeV

    The results of experimental investigations are presented to study a forward-backward asymmetry in the n-p scattering angular distribution for angles from 34 deg to 116 deg. To improve the precision of the measurements the neutron detector efficiency factor was analyzed in the 5-25 MeV energy range. Features of the time-of-flight spectrum are discussed. The data obtained confirm the asymmetry predicted by the phase shift evaluations

  1. Cavity Formation in Aluminium Irradiated with a Pulsating Beam of 225 MeV Electrons

    Singh, Bachu Narain; Bilde-Sørensen, Jørgen; Leffers, Torben;

    1984-01-01

    High-purity aluminium was irradiated with a pulsating beam of 225 MeV electrons to a maximum dose of 0.035 dpa with a helium generation rate of up to 17 appm/dpa. The irradiated samples contained cavities in the size range 5 to 70 nm. In a zone of up to 14 μm from the grain boundaries cavity size...

  2. Measurement of the Detection Efficiency of the Kloe Calorimeter for Neutrons Between 20 and 174 Mev

    Gauzzi, P.; Anelli, M.; Battistoni, G.; Bertolucci, S.; Bini, C.; Branchini, P.; Curceanu, C.; de Zorzi, G.; di Domenico, A.; di Micco, B.; Ferrari, A.; Fiore, S.; Gauzzi, P.; Giovannella, S.; Happacher, F.; Iliescu, M.; Martini, M.; Miscetti, S.; Nguyen, F.; Passeri, A.; Prokofiev, A.; Sala, P.; Sciascia, B.; Sirghi, F.

    2008-06-01

    The detection efficiency of a KLOE calorimeter prototype to neutrons of kinetic energy of 21, 46 and 174 MeV has been measured by exposing it to the neutron beam of the The Svedberg Laboratory, Uppsala. The measurement of the neutron detection efficiency of a NE110 scintillator provided a reference calibration. At the lowest trigger threshold, the ratio between the calorimeter and scintillator efficiency ranges from 2.5 to 3.2.

  3. Ternary fission with 4He emission in 16O(144 Mev) + 232Th and 12C(108 Mev) + 197Au reactions

    Results of coincidence study of 4He emission with fission fragments in 12C (108 MeV) ions with sup(197)Au target and 16O (144 MeV) ions with sup(223)Th target reactions are presented. On the basis of Monte Carlo kinematic simulation of nuclear reactions analysis of energy and velocity spectra of α-particles has been performed. The conclusion has been performed. The conclusion has been drawn that the main source of 4He emission was the evaporation from a fissioning compound nucleus. Substantial part of α-particles was emitted from fully accelerated fission fragments. Some of 4He nuclei with mean energy of about 16 MeV emitted mainly perpendicular to the fission axis were identified as similar to long range α-particles in ternary fission of heavy nuclei with low excitation energy. Multiplicities of emission of these particles are considerably higher than those at low excitation energy. Comparison of experimental results with statistical model calculations has been made

  4. Study of the reaction mechanisms leading to projectile fragmentation in 40 Ar + Ag nat reactions at 30 MeV and 60 MeV per nucleon

    This work is devoted to a study of the reaction mechanisms leading to projectile fragmentation in heavy ion collisions at intermediate energy (less than 100 MeV per nucleon). In contradiction with some theoretical calculations, inclusive measurements of projectile fragments as well as correlation measurements between projectile and target fragments in the reaction 40Ar + natAg at 30 MeV and 60 MeV per nucleon do not show any evidence for a change in the reaction mechanism in this energy range. Angular, mass and velocity correlations between projectile and target fragments enable us to reject mass transfer from projectile to target as a leading mechanism in projectile fragmentations. However, a coherent description of the data can be given either in the framework of an abrasion-ablation model in which the primary fragments of the projectile and of the target are produced with very low excitation energies, or assuming a two-body reaction, reminiscent of the first steps of deeply inelastic collisions, in which the dissipated energy is shared about equally between strongly excited projectile and target. The high excitation energies deduced from the two-body analysis bring in question our description of the fragmentation process. Thus, the excitation energy of the primary fragment is a key parameter which may be used in future experiments to distinguish between different reaction mechanisms

  5. Non-elastic cross-sections for neutron interactions with carbon and oxygen above 14 MeV

    In the light of the new generation of high energy (less than or equal to 80 MeV) neutron therapy facilities currently being tested, the need for neutron kerma factors in the range from 15 to 80 MeV on carbon and oxygen has become of urgent importance. Not enough experimental data currently exist or are likely to be measured soon, so a nuclear model is essential for interpolation or, less satisfactorily, extrapolation of available data. The use of a suitable model, applicable to light nuclei, is shown to be crucial. Such a model is described, and good agreement between its results and the experimental data in the energy range of interest is reported. Comparisons between the model predictions and the ENDF/B-V evaluation of the non-elastic cross section for carbon between 15 and 20 MeV indicate that a re-evaluation of ENDF is required. 35 refs., 12 figs., 6 tabs

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

    Inoue, Yoshiyuki [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States); Murase, Kohta [Inst. for Advanced Study, Princeton, NJ (United States). School of Natural Sciences; Madejski, Grzegorz M. [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States); Uchiyama, Yasunobu [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States); Rikkyo Univ., Tokyo (Japan). Dept. of Physics

    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.

  7. Multiple Coulomb scattering of 160 MeV protons

    Gottschalk, B.; Koehler, A. M.; Schneider, R. J.; Sisterson, J. M.; Wagner, M. S.

    1993-06-01

    We have measured multiple Coulomb scattering of 158.6 MeV protons in fourteen materials from beryllium to uranium including brass and several plastics. Targets ranged from thin (negligible energy loss) to very thick (greater than the mean proton range). The angular distribution was measured by means of a single diode dosimeter scanned typically over two decades of dose falloff. Each data set was fitted with a Molière scattering distribution (using Bethe's tables) to extract a characteristic angle θ M as well as a Gaussian distribution to extract a characteristic angle θ 0. As expected in the small angle region, the Gaussian fits about as well as the Molière shape. The θM values were compared with Molière's predicted value ( {χ cB}/{2}) including Fano's correction for scattering by atomic electrons and using Molière's formalism to account for energy loss and/or compound targets or mixtures. The distribution of the deviation from theory for 115 independent measurements is approximately normal, with a mean value - 0.5 ± 0.4% and an rms spread of 5%. The θ 0 values were compared with Highland's formula and with an "improved Highland" formula of Lynch and Dahl, using our own generalization to thick targets. The overall accuracy of Highland's formula is slightly worse than that of Molière theory. The distribution of the deviation from theory for 115 independent measurements is normal, with a mean value - 2.6 ± 0.5% and an rms spread of 6%. The Lynch formula gives nearly the same average statistics though details of the fit are different. Some data were taken for very thick targets (thickness greater than 97% of the mean proton range) where only a fraction of the incident protons emerge. Here the characteristic angle appears to level off or even to fall slightly with target thickness perhaps due to the filtering out of large-angle protons. These measurements are presented but were excluded from the comparison with theory. We have reviewed six other published

  8. Neutron doses in an 8 MeV linear accelerator and an 18 MeV betatron

    Using uranium fission track dosimeters, dose distributions of neutrons produced by photonuclear reaction in the shielding material were measured near an 8 MeV linear accelerator and an 18 MeV betatron. Dose equivalents, as a function of bremsstrahlung doses in the central beam, are given for different points outside the irradiation field, in particular at the location of the patient. The neutron production was determined as a function of photon energy between 8 and 18 MeV and compared with literature values. (orig./HP)

  9. Experiments on n-p scattering with 260-Mev neutrons

    Kelley, E.; Segre, E.; Leith, C.; Wiegand, C.

    1950-03-06

    Neutrons produced by 350 Mev protons impinging on beryllium are scattered by hydrogen. The authors measure the differential scattering cross section as a function of the scattering angle. Results are summarized here.

  10. EXPERIMENTS ON N-P SCATTERING WITH 260 MEV NEUTRONS

    Kelly, E.; Leith, C.; Segre, E.; Wiegand, C.

    1950-03-06

    Neutrons produced by 350 Mev protons impinging on beryllium are scattered by hydrogen. We measure the differential scattering cross section as a function of the scattering angle. Results are summarized in Fig. 3 of the paper.

  11. Performances of large BGO crystals below 20 MeV

    This paper presents the performances of large tapered BGO crystals to low energy photons of 6 to 20 MeV. The read-out of the crystals was made with large area photodiodes associated to shaping amplifiers

  12. Production of 14 MeV neutrons by heavy ions

    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.

  13. Diagnostics for the 400 MeV FNAL Linac

    The last four 201 MHz alvarez tanks of the twenty-year-old, 200 MeV Fermilab Linac are being replaced by seven high-gradient (7 KV/m), high-frequency (805 MHz) side-coupled-cavity structures to produce a 400 MeV beam for injection into the Booster. Good, reliable beam diagnostics are an important factor in the success of this project. This paper discusses the diagnostic systems

  14. A novel source of MeV positron bunches driven by energetic protons for PAS application

    Tan, Zongquan; Xu, Wenzhen; Liu, Yanfen; Xiao, Ran; Kong, Wei; Ye, Bangjiao

    2014-11-01

    This paper proposes a novel methodology of MeV positrons generation for PAS application. Feasibility of this proposal analyzed by G4Beamline and Transport have shown reasonable success. Using 2 Hz, 1.6 GeV, 100 ns and 1.5 μC/bunch proton bunches for bombarding a graphite target, about 100 ns e+ bunches are generated. Quasi-monochromatic positrons in the range of 1-10 MeV included in these bunches have a flux of >107/s, peak brightness of 1014/s. A magnetic-confinement beamline is utilized to transport the positrons and a "Fast Beam Chopper" is unprecedentedly extended to chop those relativistic bunches. The positron beam can be finally characterized by the energy range of 1-10 MeV and bunch width from one hundred ps up to 1 ns. Such ultrashort bunches can be useful in tomography-type positron annihilation spectroscopy (PAS) as well as other applications.

  15. Comprehensive Measurement of Neutron Yield Produced by 62 MeV Protons on Beryllium Target

    A low-power prototype of neutron amplifier, based on a 70 MeV, high current proton cyclotron being installed at LNL for the SPES RIB facility, was recently proposed within INFN-E project. This prototype uses a thick Beryllium converter to produce a fast neutron spectrum feeding a sub-critical reactor core. To complete the design of such facility the new measurement of neutron yield from a thick Beryllium target was performed at LNS. This measurement used liquid scintillator detectors to identify produced neutrons by Pulse Shape Discrimination and Time of Flight technique to measure neutron energy in the range 0.5-62 MeV. To extend the covered neutron energy range 3He detector was used to measure neutrons below 0.5 MeV. The obtained yields were normalized to the charge deposited by the proton beam on the metallic Beryllium target. These techniques allowed to achieve a wide angular coverage from 0 to 150 degrees and to explore almost complete neutron energy interval. (authors)

  16. Comprehensive Measurement of Neutron Yield Produced by 62 MeV Protons on Beryllium Target

    Osipenko, 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

    2013-01-01

    A low-power prototype of neutron amplifier, based on a 70 MeV, high current proton cyclotron being installed at LNL for the SPES RIB facility, was recently proposed within INFN-E project. This prototype uses a thick Beryllium converter to produce a fast neutron spectrum feeding a sub-critical reactor core. To complete the design of such facility the new measurement of neutron yield from a thick Beryllium target was performed at LNS. This measurement used liquid scintillator detectors to identify produced neutrons by Pulse Shape Discrimination and Time of Flight technique to measure neutron energy in the range 0.5-62 MeV. To extend the covered neutron energy range He3 detector was used to measure neutrons below 0.5 MeV. The obtained yields were normalized to the charge deposited by the proton beam on the metallic Beryllium target. These techniques allowed to achieve a wide angular coverage from 0 to 150 degrees and to explore almost complete neutron energy interval.

  17. Cross sections from proton irradiation of thorium at 800 MeV

    Engle, Jonathan W; Weidner, John W; Wolfsberg, Laura E; Fassbender, Michael E; Jackman, Kevin; Couture, Aaron; Bitteker, Leo J; Ullmann, John L; Gulley, Mark S; Pillai, Chandra; John, Kevin D; Birnbaum, Eva R; Nortier, Francois M

    2013-01-01

    Nuclear formation cross sections are reported for 65 nuclides produced from 800-MeV proton irradiation of thorium foils. These data are useful as benchmarks for computational predictions in the ongoing process of theoretical code development and also to the design of spallation-based radioisotope production currently being considered for multiple radiotherapeutic pharmaceutical agents. Measured data are compared with the predictions of three MCNP6 event generators and used to evaluate the potential for 800-MeV productions of radioisotopes of interest for medical radiotherapy. In only a few instances code predictions are discrepant from measured values by more than a factor of two, demonstrating satisfactory predictive power across a large mass range. Similarly, agreement between measurements presented here and those previously reported is good, lending credibility to predictions of target yields and radioimpurities for high-energy accelerator-produced radionuclides.

  18. Modeling the Bremsstrahlung of 30-60 MeV electrons. Source term calculation

    The photofission process has been recently considered for the production of neutron rich isotopes and the development of radioactive beams. The radioprotection hazard should be studied accordingly. A survey of the radiative electron energy loss theory is reported in order to estimate numerically the Bremsstrahlung production of thick targets. The resulted Bremsstrahlung angular and energy theoretical distributions delivered from W and UCx thick converters are presented and compared with previous results. This study is focused on initial kinetic energies of the electron beam included in the range 30-60 MeV, suitable for the production of large photon yields able to induce the 238U fission. The source term for 50 MeV incident electrons is reported for radioprotection purposes. (authors)

  19. The 59Co(n,α) reaction from threshold to 30 MeV

    Neutron-induced reactions that result in alpha-particle emission have been investigated for the target nucleus 59Co over the neutron energy range from threshold to 30 MeV with the spallation neutron source at WNR/LAMPF. Double-differential cross sections were measured at alpha-particle emission angles of 30, 60, 90 and 135 degree. Integrated cross sections agree well with activation data below 14 MeV where only the 59Co(n,α)56Mn reaction contributes to alpha-particle emission. At higher energies, the integrated alpha-particle emission cross section exceeds the activation data. The results will be interpreted in terms of statistical and pre-compound reaction mechanisms. The sensitivity to nuclear level density parameters will be discussed

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

    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. PMID:26115205

  1. Calculations of an HPGe detector peak efficiency curve up to 11 MeV with EGS4 and GEANT4

    We determined an efficiency curve of an HPGe detector in the energy range of 0.3 - 11 MeV within 0.5% accuracy with the measured data of the 14N(n,γ)15N reaction and the aid of the Monte Carlo cords EGS4 and GEANT4. (author)

  2. An evaluation of the neutron-induced reaction cross sections on carbon from 10 to 20 MeV

    Available data on the neutron-induced reactions on carbon are reviewed for the energy range from 10 to 20 MeV. Evaluated cross sections obtained at Bruyeres-le-Chatel are discussed. Comparisons with coupled-channel calculations are presented for the total, elastic and inelastic (to the 2+ level) cross sections of 12C

  3. Modification of EXIFON code and analysis of O16+n reactions in En=20-50 MeV

    Murata, Toru [Nippon Nuclear Fuel Development Co. Ltd., Oarai, Ibaraki (Japan)

    1997-03-01

    To evaluate the nuclear data concerning neutron induced reactions of O-16 and N-14 in the incident energy range of 20-50 MeV, the statistical multistep reaction code EXIFON was modified to include the outgoing channels of deuteron, triton and He-3. The calculated double differential cross sections (DDXs) with the modified code are compared with experimental DDXs. (author)

  4. Demonstration of multilayer reflective optics at photon energies above 0.6 MeV

    Brejnholt, Nicolai F.; Soufli, Regina; Descalle, Marie-Anne;

    2014-01-01

    Focusing optics operating in the soft gamma-ray photon energy range can advance a range of scientific and technological applications that benefit from the large improvements in sensitivity and resolution that true imaging provides. An enabling technology to this end is multilayer coatings. We show...... that very short period multilayer coatings deposited on super-polished substrates operate efficiently above 0.6 MeV. These experiments demonstrate that Bragg scattering theory established for multilayer applications as low as 1 eV continues to work well into the gamma-ray band. (C) 2014 Optical Society...

  5. Dopant, defects and oxygen interaction in MeV implanted Czochralski silicon

    La Ferla, A.; Galvagno, G.; Raineri, V.; Priolo, F.; Carnera, A.; Gasparotto, A.; Rimini, E.

    1995-03-01

    An oxygen precipitation phenomenon was evidenced on high energy implanted Czochralski silicon samples. Al, Si, P, O and C ions with nergies in the 1-6.8 MeV range and doses in the 4 × 10 14-1 × 10 15 / cm 2 range were single or double implanted in CZSi. A strong interaction was evidenced between the implanted species, the damage and the oxygen present in the substrates after annealing at 1100 or 1200°C for 30 min. The oxygen precipitation is greatly enhanced by the presence of Al that interacting with O results almost completely electrically inactive.

  6. A study on the proton beam energy(50 MeV) measurement and diagnosis (II)

    Chae, Jong Suh; Lee, Dong Hoon; Kim, Yoo Suk; Park, Chan Won; Lee, Yong Min; Hong, Sung Suk; Lee, Min Yong; Lee, Ji Sub; Hah, Hang Hoh [Korea Cancer Center Hospital of Korea Atomic Energy Research Institute, Seoul (Korea, Republic of)

    1995-02-01

    The main purpose of this project is the precise ion measurement of proton beam energy extracted at RF 25.89 MHz from the MC-50 cyclotron of SF type. There are several method for particle energy measurement. We measured the 50 MeV proton energy by using the E-{Delta}E method in 1993. And also in our experiment used range, reapproval of energy of extracted proton beam at RF 25.89 MHz was performed, which attained the same energy with the result used elastic scattering within the error range. 10 figs, 2 pix, 3 tabs, 3 refs. (Author).

  7. Semiclassical distorted wave model analysis of inclusive (N, N'x) reactions for incident energies up to 400 MeV

    The semiclassical distorted wave (SCDW) model with the Wigner transform of a one-body density matrix is applied to analyses of multistep direct processes in (p, p'x) reactions on 12C, 90Zr, and 197Au at incident energies near 150 MeV, and 392 MeV (p, p'x) and 346 MeV (p, nx) reactions on 40Ca. The calculations show good agreement with experimental double-differential cross sections over a wide mass range of target nuclei, except at backward angles. (author)

  8. WIND. Nuclear data library for transactinides at energies up to 100 MeV. Version 1. Description and files

    The nuclear cross section data library WIND contains ENDF/B-6 formatted cross section data for neutron induced fission and threshold reactions (n,xn), (n,pxn) and (n,αxn) for 232-238U, 237,239Np and 236-244Pu at energies up to 100 MeV. It was created at the Institute of Nuclear Power Engineering, Obninsk to meet requirements on nuclear data for waste incineration process in the accelerator based units. The current version of WIND contains also the preliminary evaluated data for proton induced reactions on 238U in the energy range up to 100 MeV. (author)

  9. Tests of health physics detectors and dosimeters to 6 and 9 MeV gamma-radiation

    The CEA health physicists working group on standardization and testing of detectors for the measurements of external exposure has set up and calibrated a capture #betta# beam. 6 and 9 MeV energies were obtained by means of Ti and Ni targets. These beams made it possible to determine the response of a number of detectors and dosimeters used in health physics to these energy ranges. Most generally, these tests showed that at 6 or 9 MeV the responses of instruments calibrated with 60Co #betta#-rays could vary as much as a factor 2 when compared to the maximun of the absorbed dose in a human body

  10. 25Na and 25Mg fragmentation on 12C at 9.23 MeV per nucleon at TRIUMF

    HERACLES is a multidetector that is used to study heavy-ion collisions, with ion beams with an energy range between 8 to 15 MeV per nucleon. It has 78 detectors axially distributed around the beam axis in 6 rings allowing detection of multiple charged fragments from nuclear reactions. HERACLES has 4 different types of detectors, BC408/BaF2 phoswich, Si/CsI(Tl) telescope, BC408/BC444 phoswich and CsI(Tl) detectors. The multidetector has been run with a radioactive 25Na beam and a stable 25Mg beam at 9.23 MeV per nucleon on a carbon target.

  11. Use of the nuclear model code GNASH to calculate cross section data at energies up to 100 MeV

    The nuclear theory code GNASH has been used to calculate nuclear data for incident neutrons, protons, and deuterons at energies up to 100 MeV. Several nuclear models and theories are important in the 10--100 MeV energy range, including Hauser-Feshbach statistical theory, spherical and deformed optical model, preequilibrium theory, nuclear level densities, fission theory, and direct reaction theory. In this paper we summarize general features of the models in GNASH and describe the methodology utilized to determine relevant model parameters. We illustrate the significance of several of the models and include comparisons with experimental data for certain target materials that are important in applications

  12. Response of electret dosemeters to eletrons with energies of 3 MeV, 7 MeV, 11 MeV

    The response of the electret dosemeter to electrons of 3,7 and 11 MeV from an accelerator Mevatron 12 is studied. Two external coatings (polyethylene or nylon) are used and a comparative evaluation is presented. (M.A.C.)

  13. A calender of high multiplicity 16O induced reactions in Ag(Br) at 200A MeV

    This calendar contains information about all charged particles in 50 high multiplicity 16O + 107Ag or 80Br events in nuclear emulsions between 200A MeV and 220A MeV. A stack of 26 Ilford G5 pellicles, each 10*10*0.06 cm3, has been exposed horizontally to the 250A MeV 16O beam from the Berkeley Bevalac with a flux of 5*104 ions/cm2. All charged particles with a range >= 5 μm are registered and indentified by conventional methods. Except for Z=1 particles, no mass determination could be performed experimentally and the adopted mass values are otherwise those of the most stable isotopes. The tables could be used to: Estimation of source velocity. Correlation studies of various kind - angles, phase space etc. Flow tensor calculations. (author) (50 tables, 50 figures)

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

    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

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

    Mondal, J., E-mail: jmondal@barc.gov.in; 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.

    2015-09-21

    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 LaB{sub 6} thermionic gun. This paper presents the structure design, beam dynamics simulation, fabrication and experimental results of the 1 MeV auto-focusing SW linac.

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

    Crespi, F.C.L., E-mail: fabio.crespi@mi.infn.it [Dipartimento di Fisica, Università di Milano, Milano I-20133 (Italy); INFN, Sezione di Milano, Milano I-20133 (Italy); Avigo, R.; Camera, F. [Dipartimento di Fisica, Università di Milano, Milano I-20133 (Italy); INFN, Sezione di Milano, Milano I-20133 (Italy); Akkoyun, S. [Department of Physics, Faculty of Science, Cumhuriyet University, Campus 58140, Sivas (Turkey); Ataç, A. [Department of Physics, Faculty of Science, Ankara University, Tandoðan 06100, Ankara (Turkey); Bazzacco, D; Bellato, M. [INFN, Sezione di Padova, Padova I-35131 (Italy); Benzoni, G.; Blasi, N. [INFN, Sezione di Milano, Milano I-20133 (Italy); Bortolato, D. [INFN, Laboratori Nazionali di Legnaro, Legnaro IT-35020 (Italy); Bottoni, S.; Bracco, A. [Dipartimento di Fisica, Università di Milano, Milano I-20133 (Italy); INFN, Sezione di Milano, Milano I-20133 (Italy); Brambilla, S. [INFN, Sezione di Milano, Milano I-20133 (Italy); Bruyneel, B. [CEA-Saclay DSM/IRFU/SPhN, Gif-sur-Yvette 91191 (France); Ceruti, S. [Dipartimento di Fisica, Università di Milano, Milano I-20133 (Italy); INFN, Sezione di Milano, Milano I-20133 (Italy); Ciemała, M. [The Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Krakow (Poland); Coelli, S. [INFN, Sezione di Milano, Milano I-20133 (Italy); Eberth, J. [Institut für Kernphysik, Universität zu Köln, Zülpicher Str. 77, Köln D-50937 (Germany); Fanin, C.; Farnea, E. [INFN, Sezione di Padova, Padova I-35131 (Italy); and others

    2013-03-21

    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({sup 11}B,nγ){sup 12}C at E{sub beam}=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.

  17. Phase-shift analysis of NN scattering below 160 MeV: Indication for a strong tensor force

    A new phase-shift analysis of NN scattering in the energy range 15--160 MeV is presented. The analysis is based on the carefully reviewed world pp+np data, including recent results for higher-order spin observables in n-p scattering. The latter are essential to determine the mixing parameter var-epsilon 1 which is directly related to the isoscalar tensor force. var-epsilon 1 displays a high trend, in agreement with recent analyses above 140 MeV, and is only reproduced by potential models with a strong tensor force. The prediction of the full Bonn potential is too low by 20% for energies above 40 MeV. All other I=0 phase shifts show agreement with potential models; in particular, the notorious problem with 1P1 around 50 MeV has disappeared. Around 25 MeV a ten parameter fit based purely on np data agrees with the corresponding fit to the pp data and reveals no indication of anomalous charge independence breaking

  18. Development and application of a detector for absolute measurement of neutron fluence rate in MeV region

    The development and performance of the DTS (Dual Thin Scintillator) for the absolute measurement of the neutron fluence rate between 1 and 15 MeV is decribed. The DTS detector consists of a pair of organic scintillators in a dual configuration, where the incident produces a proton-recoil which is detected in a 2Π geometry therefore avoiding the effect of the escape of protons. Thin scintillators are used resulting in small multiple scattering corrections. The theoretical caluclations of detector efficiency and proton-recoil spectrum were performed by means of a Monte Carlos code - CARLO DTS. The calculated efficiency was compared to the experimental one at two neutron energies namely 2.446 MeV and 14.04 MeV applying the Time Correlated Associated Particle technique. The theoretical and experimental efficiencies agreed within the experimental uncertainties of 1.44% and 0.77%, respectively. The performance of the DTS has been verified in an absolute 235U(n,f) cross section measurement between 1 and 6 MeV neutron energy. The cross section results were compared to those obtained replacing the DTS detector by the NBS (National Bureau of Standards, USA) Black Neutron Detector. The agreement was excellent in the overlapping energy interval of the two experiments (between 1 and 3 MeV), within the estimated uncertainly in the range of 1,0 to 1,7%. The agreement with the most recent evaluation from the ENDF/B-VI was excellent in almost all the energy range between 1 and 6 MeV. The 235U(n,f) cross section, average over the 252Cf fission neutron spectrum has been evaluated. The result including the cross section values of the present work was 1220 mb, in excellent agreement with the average value among the most recent measurements, 1227 +- 12 mb, and with the value 1213 mb, using the ENDF/B-VI data. (author)

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

    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 (16O(n,p)16N→16O⁎→16O+γ). 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 228Th decay chain, the highest energy gamma ray available from a natural radionuclide. The 7.13 s half-life of the 16N 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, 238Pu/13C, shows that the low-energy continuum from the facility is reduced by a factor ∼30 and the gamma-ray rate is ∼100 times higher at 6.129 MeV

  20. Temporal Structure of MeV Electron Precipitation

    Millan, R. M.; Lorentzen, K. R.; Lin, R. P.; Smith, D. M.

    2001-12-01

    On January 12, 2000, the MAXIS (MeV Auroral X-ray Imaging and Spectroscopy) long duration balloon experiment was launched from McMurdo, Antarctica carrying x-ray instrumentation designed to search for MeV electron precipitation similar to the event observed in 1996 over Kiruna, Sweden (L=5.8). MAXIS detected seven x-ray bursts with significant flux extending above 0.8 MeV during the 18 day flight in addition to extended periods of softer X-ray activity. These seven events are characterized by an extremely flat spectrum ( ~E-1.7) indicating that the bulk of precipitating electrons producing the x-rays is at relativistic energies. The bursts were detected between magnetic latitudes 58o-67o (corresponding to L-values between 3.8-6.7) with durations varying from several minutes to several hours. The MeV bursts were found to occur preferentially in the late afternoon/dusk sectors (14:30-00:00 MLT) while softer precipitation was detected at all magnetic local times. Two of the strongest MeV events detected by MAXIS show strong modulation of the x-ray count rate at ULF timescales ( ~150 s) similar to modulations observed during the Kiruna event at 100-200 s. We present results from temporal analysis of the MAXIS germanium spectrometer data and examine ground-based and spacecraft observations for evidence of coincident ULF wave activity.

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

    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.

  2. Heavy-ion hot hadron matter freezes out at T=170-320 MeV?

    Vovchenko, Volodymyr

    2015-01-01

    The conventional hadron-resonance gas (HRG) model with the Particle Data Group (PDG) hadron input and the mass dependent eigenvolume corrections is employed to fit the ALICE hadron mid-rapidity yield data on the most central Pb+Pb collisions. For the case of the point-like hadrons a well-known fit result of $T \\sim 155$ MeV is reproduced. However, when we apply the eigenvolume corrections with the mass-proportional eigenvolume $v_i \\sim m_i$, fixed to the realistic proton hard-core radius $r_p \\simeq 0.4-0.5$ fm, we observe a second minimum in the temperature dependence of the $\\chi^2$, located at the significantly higher temperatures. For instance, at $r_p = 0.5$ fm the fit quality is better than in the point-particle HRG case in a very wide temperature range of $170-320$ MeV, with the global minimum located at $T \\simeq 275$ MeV and $\\chi^2/N_{\\rm dof} \\simeq 1.5$. These results show that one cannot extract the chemical freeze-out temperature with high reliability from the LHC hadron yield data. Implication...

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

    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.

  4. Online calibration of neutrino liquid scintillator detectors above 10 MeV

    Chepurnov, A. S.; Gromov, M. B.; Shamarin, A. F.

    2016-02-01

    Online calibration of neutrino liquid scintillator detector at energies above 10 MeV is very important for study of such rare process as supernova and for correct calculation of backgrounds if spectral properties is the focus of researches. The traditional procedure implies the usage of radioactive sources with well-known spectral properties but such approach is limited by available radioactive sources, upper possible energies (∼10-11 MeV) and dangerous for ultra low background environment of modern detectors. The approach we propose is based on simulation of events with controllable UV double LED pulser. The LED's main wavelength fits the scintillator excitation wavelength. This technique allows to simulate physical events within the detector in very wide energy range from a few hundred keV to about 50 MeV. Additional studies like pile-up analysis can be performed due to double-LEDs scheme which generates two delayed signals with different adjustable amplitudes. The delay time is also adjustable parameter.

  5. Study of elastic pion scattering from 9Be, 28Si, 58Ni, and 208Pb at 162 MeV

    Elastic pion scattering from 9Be, 28Si, 58Ni, and 208Pb at 162 MeV is analyzed and compared with an optical model theory which incorporates a pion--nucleon range. Excellent fits to the data are obtained in all but one case. The fitted values of the pion--nucleon range, as well as other fitted values are listed. 108 references

  6. 3 MeV Test Stand commissioning report

    Bellodi, Guilia; Andreassen, O; Comblin, J-F; Dimov, V; Lallement, J-B; Martin, C; Midttun, O; Ovalle, E; Raich, U; Roncarolo, F; Rossi, C; Scrivens, R; Vollaire, J; Yarmohammadi Satri, M; Zocca, Z

    2013-01-01

    Linac4 is a normal-conducting 160 MeV H- linear accelerator, presently under construction, that will replace the present 50 MeV Linac2 as injector of the CERN proton accelerator complex with the goal of increasing the LHC luminosity. The Linac4 front-end, composed of a 45 keV ion source, a Low Energy Beam Transport (LEBT), a 352.2 MHz Radio Frequency Quadrupole (RFQ) and a Medium Energy Beam Transport (MEBT) housing a beam chopper, was commissioned at the 3 MeV test stand area during the first half of 2013. This report gives details of the installation and operational systems used, describes the commissioning phases and measurements performed and summarizes the results that were finally achieved and the lessons learnt in the process.

  7. Nuclear Resonance Fluorescence from Uranium above 2 MeV

    Kwan, E.; Howell, C. R.; Raut, R.; Rusev, G.; Tonchev, A. P.; Tornow, W.; Adekola, A.; Hammond, S. L.; Karwowski, H. J.; Tompkins, J. R.; Huibregtse, C.; Kelley, J. H.; Johnson, B.

    2009-10-01

    The detection of special nuclear materials is critical to the nation's efforts to counter serious threat from nuclear terrorist attacks. A research program has been initiated at TUNL to address the need for new nuclear data on the actinides using the High-Intensity Gamma-Ray Source (HIγS). The high-intensity nearly monoenergic and 100% polarized γ-ray beams from HγS were utilized to search for dipole states in ^235U and ^238U above 2 MeV. This information is necessary for developing technologies using Nuclear-Resonance Fluorescence (NRF) to nonintrusively scan cargo for specific nuclei. The existence of strong nuclear dipole transitions in the actinides above 2 MeV is important for nuclear forensics, because interrogation photons using NRF are the most penetrating at these energies. Results from our experiments at Eγ> 2.0 MeV on uranium will be presented.

  8. An RFQ accelerator system for MeV ion implantation

    Hirakimoto, Akira; Nakanishi, Hiroaki; Fujita, Hiroyuki; Konishi, Ikuo; Nagamachi, Shinji; Nakahara, Hiroshi; Asari, Masatoshi

    1989-02-01

    A 4-vane-type Radio-Frequency Quadrupole (RFQ) accelerator system for MeV ion implantation has been constructed and ion beams of boron and nitrogen have been accelerated successfully up to an energy of 1.01 and 1.22 MeV, respectively. The acceleration of phosphorus is now ongoing. The design was performed with two computer codes called SUPERFISH and PARMTEQ. The energy of the accelerated ions was measured by Rutherford backscattering spectroscopy. The obtained values agreed well with the designed ones. Thus we have confirmed the validity of our design and have found the possibility that the present RFQ will break through the production-use difficulty of MeV ion implantation.

  9. 10MeV 25KW industrial electron LINAC

    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.

  10. Neutron-induced fission cross section of 240Pu from 0.5 MeV to 3 MeV

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

    2015-07-01

    240Pu has recently been pointed out by a sensitivity study of the Organization for Economic Cooperation and Development (OECD) Nuclear Energy Agency (NEA) to be one of the isotopes whose fission cross section lacks accuracy to meet the upcoming needs for the future generation of nuclear power plants (GEN-IV). In the High Priority Request List (HPRL) of the OECD, it is suggested that the knowledge of the 240Pu(n ,f ) cross section should be improved to an accuracy within 1-3 %, compared to the present 5%. A measurement of the 240Pu cross section has been performed at the Van de Graaff accelerator of the Joint Research Center (JRC) Institute for Reference Materials and Measurements (IRMM) using quasi-monoenergetic neutrons in the energy range from 0.5 MeV to 3 MeV. A twin Frisch-grid ionization chamber (TFGIC) has been used in a back-to-back configuration as fission fragment detector. The 240Pu(n ,f ) cross section has been normalized to three different isotopes: 237Np(n ,f ) , 235U (n ,f ) , and 238U (n ,f ) . Additionally, the secondary standard reactions were benchmarked through measurements against the primary standard reaction 235U (n ,f ) in the same geometry. A comprehensive study of the corrections applied to the data and the associated uncertainties is given. The results obtained are in agreement with previous experimental data at the threshold region. For neutron energies higher than 1 MeV, the results of this experiment are slightly lower than the ENDF/B-VII.1 evaluation, but in agreement with the experiments of Laptev et al. (2004) as well as Staples and Morley (1998).

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

    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.

  12. Resolution considerations in MeV ion microscopy and lithography

    Norarat, Rattanaporn, E-mail: rattanaporn@rmutl.ac.th [University of Applied Sciences (HES-SO), Haute Ecole Arc Ingénierie, Eplatures-Gris 17, CH-2300 La Chaux-de-Fonds (Switzerland); Faculty of Sciences and Agricultural Technology, Rajamangala University of Technology Lanna, Chiang Rai, 57120 Chiang Rai (Thailand); Whitlow, Harry J. [University of Applied Sciences (HES-SO), Haute Ecole Arc Ingénierie, Eplatures-Gris 17, CH-2300 La Chaux-de-Fonds (Switzerland)

    2015-04-01

    There a disparity between the way the resolution is specified in microscopy and lithography using light compared to MeV ion microscopy and lithography. In this work we explore the implications of the way the resolution is defined with a view to answering the questions; how are the resolving powers in MeV ion microscopy and lithography relate to their optical counterparts? and how do different forms of point spread function affect the modulation transfer function and the sharpness of the edge profile?.

  13. Crosslinking of commercial polyethylenes by 10 MeV electrons

    Commercial polyethylenes were irradiated with 10 MeV electrons to induce crosslinking. The gel fraction data measured as a function of total dose suggests that crosslinking proceeds on irradiation, as expected. A number of the properties of the irradiated polyethylenes, such as the degree of oxidation, crystallinity and thermal degradation, were studied by Fourier transform infrared/photo acoustic spectroscopy, X-ray diffraction, and a pyrolysis technique coupled with gas chromatography and mass spectrometry. The results of this study suggest that commercial polyethylenes can be crosslinked to a gel fraction of ∼70%, required for wire and cable applications, by 10 MeV electrons. (author). 35 refs., 6 figs

  14. Medical electrical equipment. Part 2-1: Particular requirements for the safety of electron accelerators in the range of 1 MeV to 50 MeV

    The International Standard has the statute of a Czech Technical Standard. The following topics are dealt with: requirements for the environment; protection against electric shock; protection against mechanical hazard; protection against unwanted or excessive radiation; protection against the ignition of flammable mixtures of anaesthetics; abnormal operation and failure states, testing the effect of environment; and requirements for design. (P.A.)

  15. Measurement of omega, the energy required to create an ion pair, for 150-MeV protons in nitrogen and argon

    The purpose of this thesis is to provide a 1% measurement of omega, the energy required to produce an ion pair, for 150 MeV protons in various gases. Such a measurement should improve the accuracy of proton ionization chamber dosimetry at the Harvard Cyclotron Laboratory. Currently, no measurements of omega exist in the energy range of 30 to 150 MeV, and present ionization chamber dosimetry at the Cyclotron relies on average values of measurements at lower and higher energies (i.e. for E < 3 MeV and E = 340 MeV). Contrary to theoretical expectations, these low and high energy data differ by as much as 9% in some gases. The results of this investigation demonstrate that the existing high energy data is probably in error, and current proton ionization chamber dosimetry underestimates omega, and hence the proton dose, by 5%

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

    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

  17. Development of mass spectrometry by high energy focused heavy ion beam: MeV SIMS with 8 MeV Cl{sup 7+} beam

    Jeromel, Luka [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Siketić, Zdravko [Ruđer Bošković Institute, P.O. Box 180, 10000 Zagreb (Croatia); Ogrinc Potočnik, Nina [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); LOTRIČ Metrology Ltd., Selca 163, SI-4227 Selca (Slovenia); Vavpetič, Primož; Rupnik, Zdravko; Bučar, Klemen [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Pelicon, Primož, E-mail: primoz.pelicon@ijs.si [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia)

    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 {sup 35}Cl{sup 7+} 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 {sup 35}Cl{sup 7+} ion beam with pulse length of

  18. Relative biological effectiveness for protons of energies up to 31 MeV

    The relative biological effectiveness (RBE) was determined for proton beams of 31,12, and 8 MeV produced at the Milano University Cyclotron. Survival curves for human cells grown in monolayer at different proton energies and for γ rays from 60Co were determined. The minimum clone size to be chosen for definition of true survivors was examined. RBE values of 1.0 +- 0.1, 1.4 +- 0.2, and 1.5 +- 0.2, respectively, were found and compared with the results of other experiments in this energy range

  19. Germination of arabidopsis thaliana seeds irradiated by MeV ions

    Dry seeds of Arabidopsis thaliana were irradiated with F ions and H ions with the energy range from keV to MeV, respectively. The inhibition of germination was investigated to display the influences of ion mass, energy and fluence. The results show that H ion irradiation is more effective in decreasing the germination rate than heavier F ion irradiation. After irradiation of F ions, a decrease-increase-decease type of germination rate-fluence response curve was found and the ion fluence at the peak position decreases with ion energy increase. The possible mechanism of above experimental results is discussed in this paper. (authors)

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

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

    2012-01-01

    In the framework of research on IVth generation reactors and high intensity neutron sources a low-power prototype neutron amplifier was recently proposed by INFN. It is based on a low-energy, high current proton cyclotron, whose beam, impinging on a thick Beryllium converter, produces a fast neutron spectrum. The world database on the neutron yield from thick Beryllium target in the 70 MeV proton energy domain is rather scarce. The new measurement was performed at LNS, covering a wide angular range from 0 to 150 degrees and an almost complete neutron energy interval. In this contribution the preliminary data are discussed together with the proposed ADS facility.

  1. Radiochemical measurement of 10-15 MeV proton induced fission yields for U-238

    The production of realistic nuclear forensics debris requires an accurate knowledge of cross sections and fission yields for large number of systems. Proton induced fission of U-238 was examined for incident energies in the range of 10-15 MeV. Fission yields were first measured directly from the irradiated materials. The valley and wing fission products were then isolated in various chemical fractions in order to increase the counting statistics leading to improvements in the fission yields. In addition to the total fission cross section and the fission mass yields for U-238, proton based reaction cross sections on U-238 and U-235 were also measured. (author)

  2. 'Cabinet-safe' study of 1-8 MeV electron accelerators

    Wells, D P; Yoon, W Y; Harmon, F

    2001-01-01

    The development of 'cabinet-safe' accelerator technology for approx 1-8 MeV electron LINACs would remove the only major barrier to large-scale 'field' applications of these accelerators. These applications range from non-destructive evaluation and assay to radiolytic degradation of hazardous waste. All field applications require large forward dose and very little lateral dose. We investigated the origin, energy, and angular distribution of unwanted lateral radiation dose from two different electron LINACS at three energies. We report on the contributions of various beam parameters to unwanted radiation dose and propose methods to control key beam parameters that significantly contribute to these doses.

  3. Neutron-proton spin-correlation parameter Azz at 68 MeV

    We report a first measurement of the spin-correlation parameter Azz in neutron-proton scattering at 67.5 MeV. The results, obtained in the angular range 105 degree ≤θc.m.≤170 degree with typical accuracies of 0.008, are highly sensitive to the 3S1-3D1 mixing parameter ε1. A phase-shift analysis based on the current world data yields a value of ε1 significantly higher than predicted by modern potential models

  4. Neutron emission in 19F+181Ta reaction at 150 MeV

    In this work we concentrate on the HMS Model and the ALICE 2014 code. In fact one of the aims of the present study is to produce new data that will provide stringent test of the code. Neutron emission and light charged particle emission are useful tools for such a study. In the experiment we measured both neutron and charged particle spectra for a range of targets, and at three 19F beam energies. In this contribution we present the angle-dependent neutron spectra for 19F + 181Ta at beam energy of 150 MeV

  5. Measurement of neutron yield by 62 MeV proton beam on a thick Beryllium target

    In the framework of research on IVth generation reactors and high intensity neutron sources a low-power prototype neutron amplifier was recently proposed by INFN. It is based on a low-energy, high current proton cyclotron, whose beam, impinging on a thick Beryllium converter, produces a fast neutron spectrum. The world database on the neutron yield from thick Beryllium target in the 70 MeV proton energy domain is rather scarce. The new measurement was performed at LNS, covering a wide angular range from 0 to 150 degrees and an almost complete neutron energy interval. In this contribution the preliminary data are discussed together with the proposed ADS facility.

  6. Application of 12 MeV proton activation to the analysis of archaeological specimens

    12 MeV proton activation analysis is applied to a variety of archaeological specimens (glass, pottery, mortar and ivory) and its usefulness studied. The method is non-destructive and Ca, Ti, V, Cr, Fe, Cu, Zn, As, Sr, Y, Zr and Sb, ranging from percentage to parts per million (ppm) level were determined. The detection limits in archaeological glass for Ti, V, Cr, Fe, As, Sr, Y and Zr are at 1-10 ppm level; Cu, Zn and Sb at 20-35 ppm level, and Ca at 150 ppm level. (author)

  7. 14 MeV neutron work at the Lawrence Livermore National Laboratory

    The 14 MeV neutron work at Lawrence Livermore National Laboratory (LLNL) covers two main areas of interest to this Symposium: (1) measurements and calculations of differential cross sections; and (2) integral measurements of the neutron and gamma emission spectra. In both areas a large number of materials have been studied, spanning a wide mass range (6 < A < 239), of interest to fusion and hybrid reactors. In this presentation a brief description of the experimental techniques and calculational analysis is given for each of the above areas and the measured and calculated cross sections are discussed. 28 refs., 7 figs., 3 tabs

  8. 14 MeV neutron work at the Lawrence Livermore National Laboratory

    Hansen, L.F.

    1985-07-01

    The 14 MeV neutron work at Lawrence Livermore National Laboratory (LLNL) covers two main areas of interest to this Symposium: (1) measurements and calculations of differential cross sections; and (2) integral measurements of the neutron and gamma emission spectra. In both areas a large number of materials have been studied, spanning a wide mass range (6 < A < 239), of interest to fusion and hybrid reactors. In this presentation a brief description of the experimental techniques and calculational analysis is given for each of the above areas and the measured and calculated cross sections are discussed. 28 refs., 7 figs., 3 tabs.

  9. Reaction mechanisms in 12C(γ,pp) near 200 MeV

    Inclusive 12C(γ,pp) cross sections have been measured with tagged photons in the range Eγ=187 endash 227 MeV using the Saskatchewan-Alberta Large Acceptance Detector (SALAD). The large angular acceptance allowed the measurement of noncoplanar pp emission. The cross sections were compared to a Monte Carlo intranuclear cascade calculation. Agreement was reasonable for the shapes of the cross sections but the calculated total cross section was 3.9 times larger than the data. copyright 1996 The American Physical Society

  10. Ion shaking in the 200 MeV XLS-ring

    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. A similar experiment in the 200 MeV XLS ring is described. In the experiments, RF voltage was applied on a pair of vertical striplines. The frequency was scanned in the range of the ion (from H2 to CO2) bounce frequencies in the ring (1-10 MHz). The response of the beam size, vertical betatron tune and lifetime was studied. (author) 19 refs.; 4 figs

  11. M-shell electron capture and direct ionization of gold by 25-MeV carbon and 32-MeV oxygen ions

    M-shell x-ray production cross sections have been measured for thin solid targets of Au for 25 MeV 12C/sup q+/ (q = 4, 5, 6) and for 32 MeV 16O/sup q+/ (q = 5, 7, 8). The microscopic cross sections were determined from measurements made with targets ranging in thickness from 0.5 to 100 μg/cm2. For projectiles with one or two K-shell vacancies, the M-shell x-ray production cross sections are found to be enhanced over those by projectiles without a K-shell vacancy. The sum of direct ionization to the continuum (DI) and electron capture (EC) to the L, M, N ... shells and EC to the K-shell of the projectile have been extracted from the data. The results are compared to the predictions of first Born theories i.e. PWBA for DI and OBK of Nikolaev for EC and the ECPSSR approach that accounts for energy loss, Coulomb deflection and relativistic effects in the perturbed stationary state theory. 25 references, 3 figures, 1 table

  12. (γ,n) reaction in nuclei of the 12<=A<=238 interval in the intermediate energy region (300 MeV-1000MeV)

    The absolute cross section of the 12C(γ,n)11C, 19F(γ,n)18F, 23Na(γ,n)22Na, 31P(γ,n)30P, 52Cr(γ,n)51Cr, 55Mn(γ,n)54Mn, 59Co(γ,n)58Co, 75As(γ,n)74As, 103Rh(γn)102Rh, 127I(γ,n)126I, 197Au(γ,n)196Au and 238U(γ,n)237U reactions were determined, experimentally, in the energy range from 300 MeV to 1000 MeV, using Bremsstrahlung photons. The measured cross sections were compared with results estimated by Monte Carlo Method applied to intranuclear cascades initiated by phothons. A functional dependence between the average value of (γ,n) absolute cross section and the mass number, were established. The (γ,n) absolute cross sections from simple relations, which transparencies of complexe nuclei for mesons and nucleons photo produced were also determined. (M.C.K.)

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

    Caputo, Regina; ComPair Team

    2016-01-01

    The gamma-ray energy range from several hundred keV to a hundred MeV has remained largely unexplored, since the observations by instruments on the Compton Gamma-Ray Observatory (1991- 2000) and on INTEGRAL (since 2002). Accurate measurements in this energy range are critical for answering a broad range of astrophysical questions, but they are particularly challenging because this range encompasses the Compton scattering/pairproduction transition zone (~10 MeV) where the interaction cross section is minimized. These interaction processes require different optimizations in both detection and event reconstruction. 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 high energy and angular resolution and with sensitivity approaching a factor of 20-50 better than COMPTEL. This instrument will be capable of measuring 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, CGRO, INTEGRAL, 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.

  14. GAMMA-LIGHT: High-Energy Astrophysics above 10 MeV

    Morselli, Aldo; Barbiellini, Guido; Bonvicini, Walter; Bulgarelli, Andrea; Cardillo, Martina; Chen, Andrew; Coppi, Paolo; Di Giorgio, Anna Maria; Donnarumma, Immacolata; Del Monte, Ettore; Fioretti, Valentina; Galli, Marcello; Giusti, Manuela; Ferrari, Attilio; Fuschino, Fabio; Giommi, Paolo; Giuliani, Andrea; Labanti, Claudio; Lipari, Paolo; Longo, Francesco; Marisaldi, Martino; Molinari, Sergio; Muñoz, Carlos; Neubert, Torsten; Orleanski, Piotr; Paredes, Josep M; Pérez-García, M Ángeles; Piano, Giovanni; Picozza, Piergiorgio; Pilia, Maura; Pittori, Carlotta; Pucella, Gianluca; Sabatini, Sabina; Striani, Edoardo; Tavani, Marco; Trois, Alessio; Vacchi, Andrea; Vercellone, Stefano; Verrecchia, Francesco; Vittorini, Valerio; Zdziarski, Andrzej

    2014-01-01

    High-energy phenomena in the cosmos, and in particular processes leading to the emission of gamma- rays in the energy range 10 MeV - 100 GeV, play a very special role in the understanding of our Universe. This energy range is indeed associated with non-thermal phenomena and challenging particle acceleration processes. The technology involved in detecting gamma-rays is challenging and drives our ability to develop improved instruments for a large variety of applications. GAMMA-LIGHT is a Small Mission which aims at an unprecedented advance of our knowledge in many sectors of astrophysical and Earth studies research. The Mission will open a new observational window in the low-energy gamma-ray range 10-50 MeV, and is configured to make substantial advances compared with the previous and current gamma-ray experiments (AGILE and Fermi). The improvement is based on an exquisite angular resolution achieved by GAMMA-LIGHT using state-of-the-art Silicon technology with innovative data acquisition. GAMMA-LIGHT will add...

  15. Neutron cross sections at 14 MeV

    Neutron activation cross sections on Nd isotopes at 14 MeV were measured using the Ge(Li) gamma-ray spectroscopy. The nonlinear least square method was used for resolving the gamma spectra. The results obtained are discussed in detail and compared with theoretical results on other isotopes

  16. The 400 MeV Linac Upgrade at Fermilab

    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.

  17. Analysis of 33 MeV Nitrogen irradiated UHMWPE

    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

  18. Linac4 crosses the 100 MeV threshold

    Corinne Pralavorio

    2016-01-01

    The new linear accelerator, which from 2020 will be the first link in the accelerator chain, has entered a new stage of its commissioning.   Members of the team in charge of the commissioning of Linac4 in the accelerator’s control room. A few hours earlier, Linac4 accelerated a beam to 107 MeV for the first time. We couldn’t have imagined a more appropriate date: on 1 July (1.07), Linac4 reached an energy of 107 MeV. Having crossed the 100 MeV barrier, the linear accelerator is now on the home straight of its commissioning. “This stage was very quick – it took less than two weeks,” says Alessandra Lombardi, deputy project leader of Linac4, in charge of the commissioning. In 2020, Linac4 will replace the existing Linac2 as the first link in the accelerator chain. It will accelerate beams of H- ions (protons surrounded by two electrons) to 160 MeV, compared to 50 MeV with Linac2. The new machine is particularly sophisticated as it comprises...

  19. 200 MeV RF linac for synchrotron injection

    Construction has been completed on an electron linear accelerator for the Brookhaven National Laboratory. This accelerator will be used for the injection of a 200 MeV electron beam into a synchrotron for lithography experiments. This paper describes the conceptual design of the linac, its e-gun pulser, and its control and timing systems. 3 figs., ref

  20. Reaction mechanisms of fast neutrons on stable Mo isotopes below 21 MeV

    A large number of new measurements with the activation technique were performed for (n,2n) and neutron-induced ΔZ=1,2 reaction cross sections on the stable molybdenum isotopes in the energy range from 13.5 to 21 MeV. First results were obtained for the 92Mo(n,2n)91Mom,92Mo(n,α)89Zrm,94Mo(n,2n)93Mom,95Mo(n,p)95Nbm,96Mo(n,p) 96Nb,96Mo(n,x)95Nbm, 97Mo(n,p)97Nb, 97Mo(n,p)97Nbm, 97Mo(n,x)96Nb, 98Mo(n,p)98Nbm, 98Mo(n,x)97Nb, 98Mo(n,x)97Nbm, and 100Mo(n,α)97Zr reactions, above 16 MeV. A significant number of high-accuracy 14 MeV measurements were performed which are in good agreement with the measurements above 16 MeV for reactions studied in both energy ranges. The rather complete database for the molybdenum isotopes was analyzed with two different sets of consistent model calculations: a local and a global approach. The global approach (a blind calculation with the TALYS code) provides a good overall description of the dominant reaction channels, although the (n,α) reactions for the heavy isotopes are overpredicted. The local approach (an adjusted calculation with the STAPRE-H code) describes the shapes and magnitudes of the excitation functions well from the reaction thresholds up to 21 MeV using a consistent parameter set, which was optimized based on all experimental information for the nuclei at hand and their immediate neighbors. The agreement between experimental and calculated data is, in general, good both at the maxima and at the tails of the excitation functions, and both for total activation cross sections of a particular channel and for cross sections leading to isomers, showing the viability of the level densities, the optical models, and the γ widths. Comparison of the two model calculations with the data indicates the relevance of an appropriate treatment for preequilibrium (PE) α-particle emission for the description of the data above 14 MeV. Comparison between the model calculations shows largely different PE deuteron emission contributions to the

  1. The nuclear response in the 54Fe(p vector, p' vector) reaction at 290 Mev

    Cross sections, analysing powers and spin-flip probabilities have been measured for inclusive inelastic scattering of 290 MeV protons from 54Fe at laboratory angles between 3.1 degrees and 20 degrees. The momentum transfers vary from small values (q ∼ 0.2 fm-1) where individual giant resonances of low multipolarity are observed, to larger values (q ∼ 1.4 fm-1) where quasielastic scattering dominates. For the observed range of momentum and energy transfers (ω ≤ 96 MeV at 20 degrees, ≤ 45 MeV at smaller angles) the spin-flip probabilities Snn and spin-flip strengths σSnn appear to be insensitive to assumptions about the reaction mechanism and are qualitatively described by a nonrelativistic model of quasielastic scattering which approximates the nuclear response by that of a semi-infinite slab with RPA correlations. Strongly enhanced Snn values are observed for ω > 25 MeV and q ≅ 100 MeV/c in agreement with similar observations for several other nuclei. The slab model gives a reasonable account of cross sections and angular distributions for the 54Fe(n,p)54Mn reaction at 298 MeV. The inclusion of damping of the response by 2 particle-2 hole excitations and of contributions from two-step processes improves the agreement with the (n,p) data. Using the experimental cross sections for (p,p') and (n,p) reactions and the measured spin-flip strengths in (p,p'), we have separated the nuclear response into spin (ΔS = 0, ΔS = 1), isospin (Tf = 1,2) and angular momentum (L 0,1,2...) components. The distribution and strengths of the Gamow Teller, the isovector giant dipole, and the (isoscalar) giant quadrupole resonances have been determined from this analysis and are compared to results from complementary reactions. Relative to quasiparticle RPA calculations the Gamow Teller quenching factors deduced from the σSnn data are slightly smaller than those from (p,n) and (n,p) reactions. (Author) (64 refs., 5 tabs., 20 figs.)

  2. High resolution 12C(γ,p) experiments at Eγ ≅ 25-75 MeV

    Absolute differential cross sections for the 12C(γ,p)11B reaction have been measured over proton detection angels ranging from 30 to 150 deg, using tagged photons of 25-75 MeV energy, for low-lying regions of residual excitation energy in 11B. Four experiments were performed at the MAX laboratory in Lund in order to provide data. Previously reported cross sections for the reaction had systematic uncertainties of a magnitude which made them agree, in spite of a large spread in absolute values. The cross sections reported, with a systematic uncertainty of 8%, remove previous ambiguities for Eγ=40-75 MeV. A reinterpretation of the states excited in11B at E about 7 MeV is also presented. The data are compared with quasi-elastic (e,e'p) results in PWIA in the same recoil momentum range. It is found that the momentum distributions do not scale for the two reaction types. Furthermore, the data are compared with the results for the inverse reaction (p,γ) in the centre-of-momentum system by detailed balance. The comparison with respect to missing momentum indicates an angular dependence in the (γ,p) reaction which is not present in the inverse (p,γ) reaction. Recent results from the MAX laboratory for the (γ,n) reaction are compared to the (γ,p) results. The mirror nuclei 11C and 11B have almost identical excitation energy spectra at Eγ=60 MeV. It is concluded that HF-RPA calculations with essential contributions of meson exchange currents provide a qualitative description of the angular distributions obtained for the (γ,p) reaction. An extension of the spherical symmetric basis for the wave function is suggested for the states at E about 7 MeV in 11B. 108 refs, 83 figs

  3. European Collaboration for High-Resolution Measurements of Neutron Cross Sections between 1 MeV and 250 MeV

    Leal, L C; Kitis, G; Guber, K H; Yuasa nakagawa, K; Koehler, P E; Quaranta, A

    2002-01-01

    The experimental determination of neutron cross section data has always been of primary importance in Nuclear Physics. Many of the salient features of nuclear levels and densities can be determined from the resonant structure of such cross sections and of their decay scheme. An associated importance of precise neutron induced reaction cross sections has resulted from the worldwide interest in Accelerator Driven Systems (ADS) that has emerged at CERN and elsewhere. Many applications, such as accelerator-based transmutation of nuclear waste, energy amplification medical research, astrophysical applications and also fusion research require nuclear data that quantitatively and qualitatively go beyond the presently available traditional evaluation.\\\\ \\\\We consider a spallation driven TOF facility at the CERN-PS with an unprecedented neutron flux (1000 times the existing ones) in the broad energy range between 1 eV and 250 MeV and with very high energy resolution. The present concept for an intense neutron source m...

  4. Evaluation of d + 6,7Li data for deuteron incident energies up to 50 MeV

    A new evaluation of the nuclear data for a particle transport calculations was performed for d + 6,7Li interactions in the energy region from 4 to 50 MeV incident energy. Use was made of the available new optical model potential for d + Li interactions. For the description of a neutron emission a new optical model potential for n + 9Be was elaborated for the neutron energies from 0.1 to 22 MeV. Global optical model potentials were used for the neutrons above 22 MeV and for protons, tritons, He-3 and alphas - in the whole energy range. The following nuclear processes were accounted for: particle evaporation and preequilibrium emission, stripping of the proton from the deuteron and direct interactions of deuterons with lithium nuclei. GNASH and ECIS96 codes were applied for the first two process descriptions, the Serber model was utilised for stripping processes and the DWUCK4 code was used for direct reaction processes modelling. Total neutron emission spectra were calculated as a sum of the spectra in all these processes. A complete transport file was finally prepared in ENDF-6 format covering the deuteron incident energies up to 50 MeV. The newly evaluated data are in good agreement with experimental data for neutron emission spectra. The evaluated data files were successfully tested with a modified version of the MCNP computer code

  5. Double sided irradiation on homogenous products of different densities at an industrial EB accelerator of 2 MeV energy

    An industrial type 2 MeV/20 kW electron beam accelerator is operational in India for development of applications and technology demonstration to the Indian industry in the field of polymer modifications and for processing of various other products. For routine monitoring of beam current during radiation processing of products at the facility, a current density measurement system was fabricated using high quality graphite material. Depth–dose distribution was experimentally measured in materials of different densities for optimizing suitable thickness for double sided irradiation under 2 MeV beam. The present paper describes the features of the current density measurement system and experiments for optimizing thickness suitable for double sided irradiation for materials of different densities. - Highlights: • A current density measurement system was fabricated using high quality graphite material for routine monitoring of electron beam current for 2 MeV ILU-6 accelerator. • Effect of double sided irradiation on products under 2 MeV electron beam has been studied. • Dose distribution in homogenous products of different densities in the range of 0.3–1.4 g/cm3 has been studied

  6. Fusion with projectiles form carbon to argon at energies between 20A and 60A MeV

    A review of the linear momentum transfer is made, considering essentially heavy targets and two important parameters in the entrance channel: the projectile energy and its mass. Over a broad mass range, and for energies up to 30A MeV, the momentum transfer scales with the mass of the projectile. At 30A MeV, the most probable value of projectile momentum transferred to the fused system is 80%, and this represents roughly 180 MEV/c per projectile nucleon. At higher bombarding energies, the momentum distribution in the fused systems, as observed from binary fission events, seems to depend on the mass of the projectile. Further studies are still needed to understand this behaviour. Finally, the decay of highly excited (E* approximately 500-800 MeV) fused systems, with masses close to 270 amu, is studied from the characteristics of both fusion fragments and light charged particles. It is shown that thermal equilibrium is reached before fission, even for such high energy deposition. However, the decay sequence is sensitive to dynamical effects and does not depend only on available phase space

  7. Measurement of the neutron spectrum from the reaction of 30-MeV deuterons on a thick beryllium target

    Measurements were made of the neutron spectrum produced by bombarding a thick beryllium target with 30-MeV deuterons at the University of California, Davis cyclotron. This spectrum is of interest in studying the effect of neutrons on materials to be used in future fusion reactors. The spectrum was inferred from the activation of two sets of detector foils placed at 00 to the deuteron beam, one immediately behind the beryllium target block, and one 40 mm to the rear. A least-squares program was used to analyze the foil activation data to obtain the fluence in each of seven energy groups. The neutron spectrum (fluence/MeV) close to the target decreases continuously with energy in the range 5-32 MeV, while the spectrum 40 mm back has a peak at about 13 MeV. The contribution from neutrons of energies less than 10 MeV is much greater than that found in previous spectral measurements made at large distances from the target. This difference is attributed to the neutrons which are emitted at large angles from the deuteron beam. These observations show the importance of evaluating the neutron spectrum near the target if samples of materials are to be irradiated in this location

  8. Excitation functions of the proton induced nuclear reactions on {sup nat}Zn up to 40 MeV

    Uddin, M.S. [Department of Physics, Kyungpook National University, 1370 Sankyok-dong, Buk-gu, Daegu 702-701 (Korea, Republic of); Institute of Nuclear Science and Technology, Atomic Energy Research Establishment, Savar, GPO Box No. 3787, Dhaka-1000 (Bangladesh); Khandaker, M.U. [Department of Physics, Kyungpook National University, 1370 Sankyok-dong, Buk-gu, Daegu 702-701 (Korea, Republic of); Kim, K.S. [Department of Physics, Kyungpook National University, 1370 Sankyok-dong, Buk-gu, Daegu 702-701 (Korea, Republic of); Lee, Y.S. [Department of Physics, Kyungpook National University, 1370 Sankyok-dong, Buk-gu, Daegu 702-701 (Korea, Republic of); Kim, G.N. [Department of Physics, Kyungpook National University, 1370 Sankyok-dong, Buk-gu, Daegu 702-701 (Korea, Republic of)]. E-mail: gnkim@knu.ac.kr

    2007-05-15

    We measured the excitation functions of the {sup nat}Zn(p,xn){sup 66,67}Ga, {sup nat}Zn(p,pxn){sup 62,65,69m}Zn, and {sup nat}Zn(p,{alpha}xn){sup 61}Cu nuclear processes up to 40 MeV by using a stacked-foil activation technique at the MC50 cyclotron of the Korea Institute of Radiological and Medical Sciences. The results were compared with the earlier reported experimental data and theoretical calculations based on the ALICE-IPPE code. We have given new data points for the formation of the above radionuclides. The present values are in good agreement with some well-measured literature values. Integral yields were also deduced from the measured cross-sections. The reported direct measured thick target yields for the formation of the {sup 66}Ga and {sup 67}Ga radionuclides at 22 MeV support our deduced yields. The optimum formation of the {sup 66}Ga and {sup 61}Cu radionuclides with minimum impurities can be obtained at 8-15 MeV and 10-20 MeV energy range, respectively. The yields and decay characteristics of the nuclide {sup 65}Zn are suitable for thin layer activation analysis.

  9. Photon activation analysis of the scraper in a 200-MeV electron accelerator using gamma-spectrometry depth profiling

    Lijuan, He; Guobing, Yu; Guangyi, Ren; Zongjin, Duan

    2014-01-01

    For a high energy electron facility, the estimates of induced radioactivity in materials are of major importance to keep exposure to personnel and to the environment as low as reasonably achievable. In addition, an accurate prediction of induced radioactivity is also essential for the design, operation and decommissioning of a high energy electron linear accelerator. The research of induced radioactivity focuses on the photonuclear reaction, whose giant resonance response in the copper is ranging from 10 MeV to 28 MeV. The 200 MeV electron linac of NSRL is one of the earliest high-energy electron linear accelerators in P. R. China. The electrons are accelerated to 200 MeV by five acceleration tubes and collimated by the scrapers made of copper. At present, it is the first retired high-energy electron linear accelerator in domestic. Its decommissioning provides an efficient way for the induced radioactivity research of such accelerators, and is a matter of great significance to the accumulation of the induced ...

  10. Cold model test of the 0.45MeV RFQ

    As the first stage accelerator of the KOMAC(Korea Multipurpose Accelerator Complex) 0.45MeV, 350MHz, CW Radio-Frequency Quadrupole (RFQ) will be built to produce proton beam. Vane shape and endplate size are decided by using a RFQ cold model with Al alloy before 0.45MeV RFQ with OFHC. To investigate the effect and electrical characteristics of tuner and stabilizer rod which are component of RFQ. As conducting materials increase by 0.1cm on undercut which has 4cm depth, a resonant frequency increase. When an endplate increases in the range of a vane end and 3cm, the resonant frequency rapidly varies, and in the range of 3cm and 6.5cm it smoothly varies, after 6.5cm it holds constant. As tuners insert to 4.5cm in the RFQ cavity, the resonant frequency of a quadrupole mode, TE210, can control to 1.88MHz. Stabilizer rod shifts a dipole mode, TE11n, from the quadrupole mode and decreases an amplitude of the dipole mode. n is a longitudinal mode number

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

    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. - Highlights: • Space grade Si solar cells were subjected to 8 MeV electron radiation. • Capacitance and conductance measurements were done before and after irradiation. • Density of interface states and the interface trap time constant is found to increase with increasing electron dose. • The displacement damage formed due to electron is not uniform throughout the active region of c-Si solar cell

  12. 6 MeV storage ring dedicated to hard X-ray imaging and far-infrared spectroscopy

    M M Haque; A Moon; T Hirai; H Yamada

    2011-02-01

    The tabletop storage ring, 6 MeV MIRRORCLE, is dedicated to hard X-ray imaging as well as far-infrared (FIR) spectroscopy. In spite of low electron energy, the 6 MeV MIRRORCLE generates hard X-rays ranging from 10 keV up to its electron energy and milliwatt order submillimetre range FIR rays. Bremsstrahlung is the mechanism for the hard X-ray generation. Images produced with 11 × geometrical magnification display a sharply enhanced edge effect when generated using a 25 mm rod electron target. Bright far-infrared is generated in the same way using a conventional synchrotron light source, but with MIRRORCLE the spectral flux is found to be ∼ 1000 times greater than that of a standard thermal source. Partially coherent enhancement is observed in the case of FIR output.

  13. Calculation of the neutron induced fission cross-section of 233Pa up to 20 MeV

    Since very recently, direct measurements of the 233Pa(n,f) cross-section are available in the energy range from 1.0 to 8.5 MeV. This has stimulated a new, self-consistent, neutron cross-section evaluation for the n+233Pa system, in the incident neutron energy range 0.01-20 MeV. Since higher fission chances are involved also the lighter Pa-isotopes had to be re-evaluated in a consistent manner. The results are quite different compared to earlier evaluation attempts. Since 233Pa is a key isotope in the thorium based fuel cycle the quality of its reaction cross-sections is important for the modeling of future advanced fuel and reactor concepts. The present status of the evaluated libraries is that they differ by a factor of two in the absolute fission cross-section and also in the threshold energy value

  14. Stopping powers of havar for 0.63 5.9 MeV protons and 2.6 24 MeV alpha particles

    Porter, L. E.; Trzaska, W. H.; Räisänen, J.; Lyapin, V.

    2004-11-01

    A transmission experiment utilizing thin foil targets has been conducted in order to establish the stopping powers of the cobalt-base alloy, havar, for 0.6-5.9 MeV protons and 2.6-24 MeV alpha particles. The basic technique of the novel experimental method used was to record both the projectile energy and the time of flight while alternating measurements with and without the target in place. The uncertainties of the proton and alpha particle data sets ranged from 1.4 to 2.3% and 1.1 to 1.5%, respectively. Modified Bethe-Bloch theory was applied to the measurements in order to ascertain values of the target mean excitation energy (I) and Barkas-effect parameter (b) for each projectile. The extracted values were I = 304.3 ± 2.4 eV and b = 1.37 ± 0.04 for the case of protons, and I = 306.3 ± 2.3 eV and b = 1.47 ± 0.03 for the case of alpha particles. The I-values are somewhat higher than the additivity-based expectation of 295.7 eV, whereas the b-values are clearly consistent with the expected range of 1.4 ± 0.1. The parameter values extracted from the measurements are appraised for compatibility with recently observed trends in values of I and of b with increasing projectile atomic number.

  15. Measurement of leakage neutron spectra from a spherical pile of zirconium irradiated with 14MeV neutrons and validation of its nuclear data

    In order to make a benchmark validation of the nuclear data for Zr, the leakage neutron spectrum from a Zr sphere of a 61-cm diameter was measured between 0.1 and 16MeV using a time-of-flight technique with a 14MeV neutron source facility, OKTAVIAN. The result was compared with the calculation using the Monte Carlo code MCNP-4A. To investigate the spectrum dependence on the individual neutron reactions, test calculations were carried out with the MCNP-4A code using the JENDL-3.2-based libraries, in which partial cross section values were reduced from the original values. From the comparison between the measured and the calculated spectra, it was found that each of the results could predict well the experiment in general. However, in detail, both ENDF/B-VI and EFF-2.4 gave considerable overestimation above 1 MeV. The JENDL-3.2 predicts the spectrum almost satisfactorily except below 0.8 MeV and around 10 MeV. The discrepancy found in JENDL-3.2 calculation is considered due to the cross section values of the (n, 2n) reaction and its secondary energy distributions (SED). The modified JENDL-3.2 library with the reduced (n, 2n) reaction values and the lower SED below 1 MeV reproduced the experiment with better agreement over the whole energy range. (author)

  16. Total photoabsorption cross sections for 1H, 2H and 3He from 200 to 800 MeV

    The total photoabsorption cross sections for 1H, 2H and 3He have been measured for incident photon energies ranging from 200 to 800 MeV. The results show clearly the changes in the nucleon resonances in going from 1H to 3He. In particular, for the D13 region the behaviour for 3He is intermediate between that for 1H, 2H and heavier nuclei. (author)

  17. Differential cross sections for pion charge exchange on the proton at 27.5 MeV

    We have measured pion single charge exchange differential cross sections on the proton at 27.5 MeV incident π- kinetic energy in the center of momentum angular range between 0 degree and 55 degree. The extracted cross sections are compared with predictions of the standard pion-nucleon partial wave analysis and found to be in excellent agreement. copyright 1998 The American Physical Society

  18. Calculated proton-induced thick-target neutron and radionuclide yields for Ep ≤ 100 MeV

    Earlier proton-induced thick-target yield calculations have been extended in proton energy range and to additional target elements, using the proton stopping cross section data of Anderson and Ziegler and cross sections modeled with the GNASH code. The targets now described include Be, C, O, Ne, Al, Si, Fe, Co, Ni, Cu, W, Pb and Bi. Thick-target yields are presented for these thirteen targets, with most extending to 100 MeV. 13 refs., 3 figs., 13 tabs

  19. Operating experience of 10 MeV industrial linac

    For the past three years, an Industrial 10 MeV RF Electron linac has been in operation at Electron Beam Centre, Navi Mumbai. This pulsed linac has an on-axis coupled cavity bi-periodic π/2 structure and operates at frequency of 2856 MHz. The linac has been tested up to a maximum beam power of 5 kW and is being used for industrial applications. A successful 24-hour continuous run, at 3 kW, established the long term stability of all the linac parameters. This paper describes the high power operating experience of the 10 MeV linac. Details of RF conditioning and performance of the linac during long term tests is presented. Effect of various linac parameters, including injection voltage, RF input power, PRF, gun filament heating power, on the output beam power and energy has been discussed. (author)

  20. Upgrade of the Brookhaven 200 MeV linac

    The Brookhaven 200 MeV linac serves as the injector for the AGS Booster, as well as delivering beam to the Biomedical Isotope Resource Center. During the past year, many linac systems have been upgraded to allow operation at 2.5 times higher average current (150 μA). This was achieved by an increase in rep-rate from 5 to 7.5 Hz, an increase in beam current from 25 mA to 37 mA, and a slight increase in pulse width to ∼530 μs. Additional upgrades were made to improve reliability and modernize old systems. This paper describes improvements made in the 35 keV and 750 keV beam transport, 200 MeV beam transport, rf transmission line, rf power supplies, control systems, and instrumentation

  1. Femtosecond Time-resolved MeV Electron Diffraction

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

    2013-01-01

    We report the experimental demonstration of electron diffraction with 130 femtosecond time resolution using bench-top MeV electron beams. High-quality, single-shot electron diffraction patterns for both polycrystalline aluminium and single-crystal 1T-TaS_{2} are obtained utilizing a 5 femto-Coulomb (~3x10^{4} electrons) pulse of electrons at 2.8 MeV. The timing jitter between the pump laser and probe electron beam was found to be ~ 100 fs. The time resolution is demonstrated by observing the evolution of Bragg and superlattice peaks of 1T-TaS_{2} following an optical pump. Our experiemntal results demonstrate the feasibility of ultimately realizing 40 fs time-resolved electron diffraction.

  2. Magnifying lens for 800 MeV proton radiography

    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.

  3. Initial Test of the PEFP 20MeV DTL

    Kim, Han-Sung; Han, Sang-Hyo; Hwang, Yong-Suk; Jang, Ji-Ho; Kim, Yong-Hwan; Kwon, Hyeok-Jung; Park, Mi-Young; Tae Seol, Kyung

    2005-01-01

    A conventional 20MeV drift tube linac (DTL) for the Proton Engineering Frontier Project (PEFP) has been developed as a low energy section of 100MeV accelerator. The machine consists of four tanks with 152 cells supplied with 900kW RF power from 350MHz klystron through the ridge-loaded waveguide coupler. We assembled the fabricated accelerator components and aligned each part with care. We have also prepared the subsystems for the test of the DTL such as RF power delivery system, high voltage DC power supply, vacuum system, cooling system, measurements and control system and so on. The detailed description of the initial test setup and preliminary test results will be given in this paper.

  4. MeV electron populations as measured on DMSP

    A dosimeter flown on the DMSP F7 spacecraft during solar minimum from January 1984 through October 1987 measured electron fluxes and dose behind four different dome thicknesses. The spacecraft was in an 840 km, circular, polar orbit with a 101 minute orbit period. Using sophisticated display and analysis software developed for the CRRES program, the DMSP data base was re-examined. Displays of the data set uncovered previously unseen phenomena to include > 2.5 MeV electron penetrations to low magnetic latitudes during magnetospheric storm periods. During three periods (1 August 1984, 8--9 February 1986 and 12 September 1986) the > 2.5 MeV electrons were measured penetrating all the way to the magnetic equator. This is the first known report of these particles at the magnetic equator at 840 km. The particle penetrations occurred during periods of high magnetic activity as indicated by Kp and other indices

  5. Evolution of the 400 MeV linac design

    MacLachlan, J.A.

    1987-11-09

    The basic premises of the conceptual design for the linac upgrade are pursued to establish lengths, gradients, power dissipation, etc., for the 400 MeV linac and matching section. The discussion is limited to accelerating and focusing components. Wherever values depend on the choice of the accelerating structure, the disk-and-washer structure is emphasized; the results are generally relevant to the side coupled cavity choice also.

  6. Construction of 35 MeV DSM at Nihon University

    High quality electron beam is needed for the excitation of the free electron laser(FEL). Construction of the 35 MeV double-sided microtron for the FEL has been started at 1984. This accelerator will feed a electron beam which has narrow energy width and low emittance. A first one turn beam line has been completed. Beam accelerating experiments and high power microwave tests are performed. (author)

  7. Construction of a pulsed MeV positron beam line

    Masuno, Shin-ichi; Okada, Sohei; Kawasuso, Atsuo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    To develop a fast (1 MeV) and short pulsed (100 ps) positron beam which enables defect behavior analysis of bulk states of materials even at high temperatures where a usual positron source would melt, we have been performing design study and construction of the beam line in a three-year program since 1994. This report describes the components, design study results and experimental results of the completed parts until now. (author)

  8. Radiation sterilization by 10 MeV electron beams

    Gamma-ray sterilization by 60Co source has been already popular in Japan. Many Kinds of medical plastic devices such as catheters, disposable syringes, dializers etc, has been irradiated at 60Co irradiation facilities instead of the conventional ethylene oxide fumigation method. On the other hand, improvement of the quality of electron accelerators has made it easier to take advantage of relatively high energy electrons which are profitable for radiation sterilization because of their high dose rate saving process hours and easiness of source handling and radiation control. So electron-beam sterilization is now under investigation in Japan and, partly, it will be practiced in the near future. Yet few data are available in the present situation. Especially for high energy electron beams near 10 MeV, more data are necessary for practical application of electron-beam sterilization. Therefore, in this study, sensitivity of Bacillus pumilus E601, the biological standard of radiation sterilization, was examined using 10 MeV electron beams from linear accelerator and sterility of the beams was also checked at each depth of plastic boards in order to get basic information for determination of sterility dose. Endospores from B. pumilus were dried on filter papers (Toyo No.1) and irradiated by 10 MeV electron beams of 60Co gamma-rays. The survival curves were shown in Fig. 1. The D values were obtained as 1.9 kGy ± 0.2 for electron beams and 1.7 kGy ± 0.1 for 60Co gamma-rays, both of which were similar. Electron beams could sterilize the endospores nearly uniformly till 3 cm depth of plastic boards at 10 MeV (Fig. 2,3). This indicates a possibility to sterilize relatively bulky products such as dializers etc. (author)

  9. True absorption and scattering of 50 MeV pions

    The inclusive pion inelastic scattering and true absorption cross sections at 50 MeV were measured for π+ on natural Li, C, Fe, Nb, Bi and for π- on C, Fe, Bi. The results show that π- cross sections are much larger than π+, the difference being significantly larger than expected from a simple Coulomb calculation. In particular, in 12C the absorption of negative pions is about twice that of positive pions

  10. Scattering of MeV neutrons from elemental iron

    Neutron elastic- and inelastic-scattering cross sections of elemental iron are measured from 1.5 to 4.0 MeV with incident-neutron resolutions of < or approx. = to 50 keV and at incident-neutron energy intervals of < or approx. = to 50 keV. Cross sections for the excitation of observed levels at 0.853, 1.389, 2.097, 2.579, 2.677, 2.974 and 3.152 MeV are determined. The observed elastic- and inelastic-scattering angular distributions fluctuate strongly with incident energy. The experimental results are averaged over broad energy intervals and interpreted in terms of spherical optical-statistical and coupled-channels models including consideration of direct-vibrational excitations. The importance of a comprehensive data base in such energy-averaged interpretations and of the direct-vibrational excitations is stressed. The present measured and calculated results, combined with those reported in the literature, are used to formulate an evaluated scattered-neutron data file in the ENDF format extending from 1.0 to 4.0 MeV. 41 references

  11. MeV ion processing applications for industry

    Ions beams with MeV energies produce a variety of interactions with matter, broadly classified as either electronic or nuclear. These interactions in turn lead to changes in the properties of the matter which may be beneficial or detrimental. In high technology industry, use is increasingly made of ion beam technologies to process novel materials. Typical applications include high energy implantation, in which the deposition of a specific element at depth within the structure of material is the required objective, and irradiation modification, in which the balance between the beneficial and the detrimental effects of the fast ion interactions is exploited. The basic principles behind MeV ion processing are described. Broad areas of application in industrial materials include effects in ion beam analysis, Thin Layer Activation for wear and corrosion measurement, carrier lifetime control in electronic devices, and the simulation of radiation damage effects in, for example, solar cells for spacecraft. New development areas are described in which subtle but potentially significant changes in the chemistry of surfaces and interfaces may be generated by exposure to MeV ion beams. (orig.)

  12. Investigation of gas stripping at 4.1 MeV for high mass negative ions

    We have used a tandem accelerator to measure charge state distributions at 4.1 MeV for negative ions ranging from carbon to uranium oxide passing through the gases helium, argon and xenon. The gas density was varied over a wide range to observe the onset of equilibrium stripping conditions. Using a 12° electrostatic deflector after the accelerator, charge states from 1+ to 8+ have been measured. For carbon, the charge state is seen to strip progressively from a low charge of around 1+ towards equilibrium with increasing gas thickness. However, for all the other ions, there is a high probability of multiple electron loss in single collisions with the gas, leading to mean charge states greater than 2 even at very low gas stripper pressure. This effect is observed to be gas-independent.

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

    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.

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

    Boutoux, G., E-mail: boutoux@celia.u-bordeaux1.fr; Rabhi, N.; Batani, D.; Ducret, J.-E. [Univ. de Bordeaux, CNRS, CEA, CELIA (Centre Lasers Intenses et Applications), UMR 5107, F-33405 Talence (France); Binet, A.; Nègre, J.-P.; Reverdin, C.; Thfoin, I. [CEA DAM DIF, F-91297 Arpajon (France); Jakubowska, K. [Institute of Plasma Physics and Laser Microfusion, Hery Street 23, 01-497 Warsaw (Poland)

    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.

  15. Luminescence properties of 100 MeV swift Si7+ ions irradiated nanocrystalline zirconium oxide

    Nanocrystalline zirconium oxide (ZrO2) has been synthesized by combustion technique. The X-ray diffraction (XRD) pattern of ZrO2 confirms the monoclinic phase. The average crystallite sizes are estimated using Scherrer's formula and found to be ∼35 nm. Surface morphology and elemental composition of the ZrO2 is analyzed using the field emission scanning electron microscope (FESEM) equipped with Energy dispersive x-ray analysis (EDX). ZrO2 pellets are irradiated with 100 MeV swift Si7+ heavy ions in the fluence range of 1 × 1010–1 × 1014 ions cm−2. The broad photoluminescence (PL) emission with peak at ∼ 466 nm is observed and attributed to F-centers. Thermoluminescence (TL) glow curves of ion irradiated samples reveal a well resolve peak at ∼ 418 K (Tm1) and an unresolved peak at ∼ 502 K (Tm2). TL intensity increases up to 3 × 1011 ions cm−2 and then TL intensity decreases as increase in fluence. TL parameters of ion irradiated ZrO2 samples are described by general order kinetics. - Graphical abstract: Thermoluminescence glow curves of 100 MeV swift Si7+ ion irradiated ZrO2. - Highlights: • Single phase of ZrO2 synthesized by combustion technique. • Sample irradiated with 100 MeV Si7+ ions for various fluence. • Highest PL and TL response at same fluence due to defect concentration. • New TL glow peak appear at 455 K for above fluence 1 × 1011 ions cm−2

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

    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.

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

    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.

  18. Polarization transfer in quasifree p-vector,n-vector reactions on C, Ca, and Pb targets at 197 MeV

    A complete set of polarization-transfer observables has been measured at 197 MeV in the quasifree region for the (p(vector sign),n(vector sign)) reactions on C, Ca, and Pb targets. Data have been obtained at laboratory scattering angles of 13 deg., 24 deg., 37 deg., and 48 deg., which span an energy-loss range up to 150 MeV, with a corresponding momentum-transfer range q=0.75-2.4 fm-1. The empirical results are compared to the observables obtained from the free nucleon-nucleon data base. Derived spin-longitudinal and spin-transverse responses for Ca are compared with those previously obtained at 346 and 495 MeV incident energies

  19. The dosimetry of 3 MeV and 14 MeV neutrons with the ferrous sulphate solution

    The aim of the present work is to determine the G value of a standard ferrous sulphate solution for neutrons with mean energies of 3 MeV and 14 MeV. The number of the transformed Fe ions is evaluated by means of a spectrophotometrical procedure and the absorbed energy is determined by applying the ionometrical method. Especial attention is payed to the calculation of the mean total dose in the irradiated sample taking radiation attenuation into account. For this purpose the spatial distribution of absorbed energy within the probe is determined. Further, it is investigated how the fraction of the γ component in the total absorbed dose varies in the sample, in order to evaluate its mean value, which is needed for the final determination of the G value for the neutron component. (orig.)

  20. The disintegration of nuclei in violent heavy ion interactions at 55 A MeV-110 A MeV

    High multiplicity 12C induced reactions in Ag(Br) at energies between 55 A MeV and 110 A MeV have been selected and investigated event by event in nuclear emulsions. Only a fraction of these events can possibly be described in terms of a normal thermal spectator-participant mechanism. Several events exhibit a violent breakup into several light and medium-mass fragments. A strong suppression of projectile associated proton- and composite particle emission in the forward direction is found in comparison with inclusive spectra. A large part of the low energy protons originates from a very slow source, with a velocity comparable to that of the heaviest fragment. The parallel fraction of the C.m. energy in each event, which is governed by the more energetic protons, has a broad distribution with a mean value of 0.61 and thus with no signals of collective production mechanisms. (orig.)

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

    Differential cross sections and analyzing powers have been measured for the 15N(p,n)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-1. In contrast, both Relativistic and standard DWIA calculations predict a maximum of A=-.7 near q=0.7 fm-1. 53 refs., 44 figs

  2. Application of calorimeters for 5 MeV EB and bremsstrahlung dosimetry

    Sato, T.; Takahashi, T.; Saito, T.;

    1993-01-01

    Graphite and water calorimeters, which were developed for use a 10 MeV electron beams (EB) at Riso National Laboratory, were used for process validation and routine dosimeter calibration at a 5 MeV EB. Water calorimeters were used for reference measurements for 5 MeV EB, the response was found to...... at 5 MeV EB. Graphite calorimeters gave reproducible readings within 3.3 % relative errors (95 % confidence level) for X-ray measurement....

  3. First H- beam accelerated at Linac4: 3MeV done, 157 MeV to go!

    Linac4 Project Team

    2013-01-01

    On 14 November, the first H- (one proton surrounded by two electrons) beam was accelerated to the energy of 3 MeV in the Linac4 - the new linear accelerator that will replace Linac2 as low-energy injector in the LHC accelerator chain.      A view of the Linac4 taken during the recent tests (top image) and the current measured by the instruments at the end of the acceleration line on 14 November (bottom image). Images: Linac4 collaboration. Using the recently installed Radio Frequency Quadrupole (RFQ) accelerator, 13 mA of current were accelerated to the energy of 3 MeV. After the successful commissioning of the Linac4 RFQ at the 3 MeV test stand completed during the first months of 2013, the whole equipment (composed of the RFQ itself, the following Medium Energy Beam Transport line and its diagnostic line) were moved to the Linac4 tunnel during summer and installed in their final position. In the meantime, a new ion source was assembled, installed and successfu...

  4. Gettering in SOI and MeV ion-implanted silicon

    Beaman, Kevin Lloyd

    1999-11-01

    Gettering schemes have been proposed and investigated for two advanced silicon materials platforms, silicon-on-insulator (SOI) and Mega-electron volt (MeV) ion implanted silicon. These platforms require novel gettering techniques suitable for low thermal budget advanced device processing. For SOI materials, the devices are separated from traditional IG sites by the buried oxide (BOX). If impurities can easily diffuse through the BOX intrinsic defects from the SOI formation process may be used as gettering sites directly below the BOX. Our findings indicate that these defects are efficient gettering sites, but that low diffusivity through the BOX may prevent any benefit for devices. Another gettering option we propose for SOI is to form laterally displaced gettering sites in the top silicon layer. We have found that by self-aligned ion implantation, a buried layer of dislocation loops can be formed which can significantly reduce the concentration of Fe in intentionally contaminated bulk samples. In SOI wafers, we have shown that lateral gettering provides an improvement in gate oxide integrity for several SOI wafer types. MeV ion implantation is used in device processing to form vertically modulated wells, which have benefits for device operation. If ions of sufficient mass and dose are used, a buried layer of defects can form near the projected range (Rp), and these defects are known to getter metallic impurities. By investigating Si and Ge as the implanted species, we were able to separate the effects of the damage region from any chemical effects. The mechanism of gettering for Fe was found to be relaxation. The gettering efficiency was found to be independent of oxygen concentration, as well as implant species and dose, provided a buried layer of dislocation loops is formed. The efficiency does depend on competitive gettering from substrate B. A second gettering region near Rp/2 was investigated and found to be the result of vacancy clusters. The thermal

  5. Stopping powers of polycarbonate for 0.36-5.94-MeV protons and 1.0-24.0-MeV α particles

    Räisänen, J.; Trzaska, W. H.; Alanko, T.; Lyapin, V.; Porter, L. E.

    2003-08-01

    The stopping powers of polycarbonate for protons of energy 0.6-5.9 MeV and α particles of energy 2.0-24.0 MeV have been measured in a transmission experiment employing thin-foil targets. The essence of the novel experimental method employed in the present measurements is to record both projectile energy and time of flight while constantly alternating measurements with and without the target foil in place. The accuracies of the proton data and α-particle data range from 2.0% to 3.0% and 2.2% to 2.7%, respectively. All of the resulting measurements were analyzed in terms of modified Bethe-Bloch theory in order to extract values of the target mean excitation energy (I) and Barkas-effect parameter (b). The composite results for the two projectiles are that I=71.52 eV and b=1.13, the former value lying about one standard deviation below the additivity value and the latter value lying about one standard deviation below the expected value of 1.4±0.1. Previous measurements of the stopping power of polycarbonate for 7Li ions were analyzed by the same method, but with the inclusion of an effective charge parameter (λ). The proton and α-particle data, with a few lower-energy points included, were analyzed for a three-parameter fit, also. Results for the three projectiles studied indicate both internal consistency and agreement with expectations based on modified Bethe-Bloch theory.

  6. Target irradiation facility and targetry development at 160 MeV proton beam of Moscow linac

    Zhuikov, B L; Konyakhin, N A; Vincent, J

    1999-01-01

    A facility has been built and successfully operated with the 160 MeV proton beam of Moscow Meson factory LINAC, Institute for Nuclear Research (INR) of Russian Academy of Science, Troitsk. The facility was created for various isotope production goals as well as for fundamental nuclear investigations at high intensity beam (100 mu A and more). An important part of the facility targetry system is a high-intensity beam monitoring collimator device. Measurements of the temperature distribution between collimator sectors, cooling water flow and temperature, and the beam current, provide an opportunity to compute beam losses and beam position. The target holder design allows easy insertion by manipulator and simultaneous bombardment of several different targets of various types and forms, and variation of proton energy on each target over a wide range below 160 MeV. The main target utilized for commercial sup 8 sup 2 Sr isotope production is metallic rubidium in a stainless-steel container. A regular wet chemistry ...

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

    Sahoo, G.S. [Accelerator Radiation Safety Section, Health Physics Division, Bhabha Atomic Research Center, Mumbai 400085 (India); Tripathy, S.P., E-mail: tripathy@barc.gov.in [Accelerator Radiation Safety Section, Health Physics Division, Bhabha Atomic Research Center, Mumbai 400085 (India); Sunil, C.; Sarkar, P.K. [Accelerator Radiation Safety Section, Health Physics Division, Bhabha Atomic Research Center, Mumbai 400085 (India)

    2013-04-21

    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 (H{sub LET}) 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.

  8. The excitation function for Li+HF-->LiF+H at collision energies below 80 meV

    Bobbenkamp, Rolf; Mudrich, Marcel; Stienkemeier, Frank

    2011-01-01

    We have measured the dependence of the relative integral cross section of the reaction Li+HF-->LiF+H on the collision energy using crossed molecular beams. By varying the intersection angle of the beams from 37{\\deg} to 90{\\deg} we covered the energy range 25 meV < E_tr < 131 meV. We observe a monotonous rise of the cross section with decreasing energy over the entire energy range indicating that a possible translational energy threshold to the reaction is significantly smaller than 25 meV. The steep rise is quantitatively recovered by a Langevin-type excitation function based on a vanishing threshold and a mean interaction potential energy ~R^-2.5 where R is the distance between the reactants. To date all threshold energies deduced from ab-initio potentials and zero-point vibrational energies are at variance with our results, however, our findings support recent quantum scattering calculations that predict significant product formation at collision energies far below these theoretical thresholds.

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

    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.

  10. A study of radiation effects of 9 and 12 MeV protons on Chinese CMOS image sensor degradation

    The 9 and 12 MeV proton irradiations of the Chinese CMOS Image Sensor in the fiuence range from 1x109 to 4xl010 cm-2and 1x109 to 2x1012 cm-2 have been carried out respectively. The color pictures and dark output images are captured, and the average brightness of dark output images is calculated. The anti-irradiation fluence thresholds for 9 and 12 MeV protons are about 4x1010 and 2x1012 cm-2, respectively. These can be explained by the change of the concentrations of irradiation-induced electron-hole pairs and vacancies in the various layers of CMOS image sensor calculated by the TRIM simulation program. (authors)

  11. Nucleon-induced reactions at intermediate energies: new data at 96 MeV and theoretical status

    Blideanu, V.; Lecolley, F.R.; Lecolley, J.F.; Lefort, T.; Marie, N.; Ban, G.; Louvel, M. [Caen Univ., Lab. de Physique Corpusculaire, ENSICAEN, IN2P3-CNRS ISMRA, 14 (France); Atac, A.; Bergenwall, B.; Blomgren, J.; Dangtip, S.; Hildebrand, A.; Hohansson, C.; Klug, J.; Nilsson, L.; Ollson, N.; Pomp, S.; Tippawan, U.; Osterlund, M. [Uppsala Univ., Nykoeping (Sweden). Dept. of Neutron Research; Tippawan, U. [Chiang Mai University, Fast Neutron Research Facility (Thailand); Elmgren, K.; Olsson, N. [Swedish Defense Research Agency, Stokholm (Sweden); Eudes, Ph.; Guertin, A.; Haddad, F.; Kirchner, T.; Lebrun, C.; Riviere, G. [Nantes Univ., Subatech, 44 (France); Foucher, Y. [CEA Saclay, Dept. d' Astrophysique, de Physique des Particules de Physique Nucleaire et de l' Instrumentation Associee, 91- Gif sur Yvette (France); Jonsson, O.; Prokofiev, A.V.; Renberg, P.U. [Uppsala Univ., Svedberg Laboratory (Sweden); Kerveno, M.; Stuttge, L. [IReS, Strasbourg (France); Le Brun, Ch. [Laboratoire de Physique Subatomique et de Cosmologie, 38 - Grenoble (France); Nadel-Turonski, P. [Uppsala Univ. (Sweden). Dept. of Radiation Sciences; Slypen, I. [Universite Catholique de Louvain (UCL), Institut de Physique Nucleaire, Louvain-la-Neuve (Belgium)

    2004-04-01

    Double-differential cross sections for light charged particle production (up to A = 4) were measured in 96 MeV neutron-induced reactions, at 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 annular range (20 - 160 degrees). 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. (authors)

  12. Nucleon-induced reactions at intermediate energies: new data at 96 MeV and theoretical status

    Double-differential cross sections for light charged particle production (up to A = 4) were measured in 96 MeV neutron-induced reactions, at 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 annular range (20 - 160 degrees). 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. (authors)

  13. Dosimetric Characteristics of Circular 6-MeV X-Ray Beams for Stereotactic Radiotherapy with a Linear Accelerator

    Wysocka, A.; Rostkowska, J.; Kania, M.; Bulski, W.; Fijuth, J.

    2000-01-01

    Dosimetric characteristics of 6 MeV circular X-ray beams of diameters ranging from 7.5 to 35.0 mm are reported. The 6-MeV X-ray beam from Clinac 2300CD was formed using additional cylindrical BrainLAB's collimators. The mechanical stability of the entire system was verified. Specific quantities measured include tissue maximum ratios (TMR), beam profiles (off-axis ratios OAR) and relative output factors. Measurements of these parameters were performed in a water phantom using small cylindrical ionization chambers and a diamond detector. Comparison of TMR values measured with the ionization chamber and the diamond detector showed no significant differences. It was shown that the latter yields more accurate results for beam profiles than ionization chambers. The mechanical and dosimetric characteristics of this radiotherapy unit are found to be suitable for stereotactic radiosurgery and radiotherapy.

  14. Low energy spread 100 MeV-1 GeV electron bunches from laser wakefield acceleration at LOASIS

    Experiments at the LOASIS laboratory of LBNL recently demonstrated production of 100 MeV electron beams with low energy spread and low divergence from laser wakefield acceleration. The radiation pressure of a 10 TW laser pulse guided over 10 diffraction ranges by a plasma density channel was used to drive an intense plasma wave (wakefield), producing acceleration gradients on the order of 100 GV/m in a mm-scale channel. Beam energy has now been increased from 100 to 1000 MeV 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 were produced from self trapped electrons through the interplay of trapping, loading, and dephasing. Other experiments and simulations are also underway to control injection of particles into the wake, and hence improve beam quality and stability further

  15. Evidence for detection of 1-10 MeV emission from the Taurus region in 1971 August

    Gruber, D. E.; Ling, J. C.

    1977-01-01

    Results are reported for three observations of the Crab Nebula with a balloon-borne actively collimated NaI detector over the energy range from 0.2 to 10 MeV. Possible changes in instrument performance and environmental background levels during the balloon flights are investigated, and fits for source strength are made over four broad energy channels. X-ray power-law spectra and pulsed-flux fractions are determined for both the Crab Nebula and its pulsar, NP 0532. A statistically significant flux greatly in excess of the power law was detected above 1 MeV during one flight; this flux, which has declined by at least a factor of 4 or 5 at the times of more recent observations, is assumed to be real and is attributed to the nebula.

  16. A study of radiation effects of 9 and 12 MeV protons on Chinese CMOS image sensor degradation

    MENG Xiang-Ti; HUANG Qiang; MA Yan-Xiu; ZHENG Yong-Nan; FAN Ping; ZHU Sheng-Yun

    2008-01-01

    The 9 and 12 MeV proton irradiations of the Chinese CMOS Image Sensor in the fluence range from 1×109to 4×1010 cm-2and 1×109 to 2×1012 cm-2 have been carried out respectively. The color pictures and dark output images are captured, and the average brightness of dark output images is calculated. The anti-irradiation fluence thresholds for 9 and 12 MeV protons are about 4×1010 and 2×1012 cm-2, respectively. These can be explained by the change of the concentrations of irradiation-induced electron-hole pairs and vacancies in the various layers of CMOS image sensor calculated by the TRIM simulation program.

  17. Development of polystyrene calorimeter for application at electron energies down to 1.5 MeV

    Miller, A.; Kovacs, A.; Kuntz, F.

    2002-01-01

    were tested: (1) real time temperature measurement during the irradiation and (2) pre- and post-irradiation temperature measurement. The advantages and drawbacks of these methods are discussed. Depth dose measurements have been carried out in the PS calorimeter to define the relationship between the...... average and the surface dose and to prove the applicability of the new low energy calorimeter for calibration purposes at 1.5 and 2 MeV electron energy. Alanine dosimeters of 2 mm thickness were used to calibrate the calorimeters and their use for nominal dose measurements was demonstrated in a series of...... intercomparisons. The use as routine dosimeters at electron accelerators operating in the energy range of 1.5-4 MeV was also demonstrated. (C) 2002 Elsevier Science Ltd. All rights reserved....

  18. Biological response of arabidopsis seed to MeV proton irradiation at different region of its embryo

    The water saturated Arabidopsis seeds were irradiated with protons in air. The ion energy is from 1.1 MeV to 6.5 MeV. According to TRIM simulation, the damaged region of the seed induced by the incident ions is near the surface region of the embryo, half of the embryo and the whole embryo, respectively. The protons with high energy can damage the shoot apical meristem (SAM) in the embryo while the protons with low energy cannot. The ion fluence used in this experiment was in the range of 4 x 109 to 1 x 1014 ions/cm2. The experimental results showed that both the germination and survival rates decrease while increasing ion fluence, and the fluence-response curve for different damaged region of the embryo has different characters. Besides SAM, which is generally considered as the main radiobiological target, the existence of a secondary target besides SAM is proposed in this paper. (authors)

  19. Radiochemical studies on the neutron- and proton-induced 7Be emission at energies up to 100 MeV

    Cross sections for 7Be emission in neutron and proton induced reaction on medium and heavy mass nuclei were measured up to 100 MeV using the activation method, radiochemical separations and γ-ray spectroscopy. For this purpose chemical separations were developed and modified to optain 7Be in a radiochemically pure form. In this work the excitation functions of (p,7Be) reactions on the target nuclei V, Nb, Au and Bi could be measured radiochemically for the first time in the energy range of 35 to 100 MeV. The cross sections for gold amount to a few μb, for vanadium to several tens of μb and for niobium to several hundred μb. (orig./HSI)

  20. A 600 MeV cyclotron for radioactive beam production

    The magnetic field design for a 600 MeV proton cyclotron is described. The cyclotron has a single stage, a normal conducting magnet coil and a 9.8 m outside yoke diameter. It has 8 sectors, with a transition to 4 sectors in the center region. The magnetic field design was done using 1958 Harwell rectangular ridge system measurements and was compared with recent 3-dimensional field calculations with the program TOSCA at NSCL. The center region 4--8 sector transition focussing was also checked with TOSCA

  1. 14MeV facility and research in IPPE

    Review of experimental facility and research, performed at 14MeV incident neutron energy in the Institute of Physics and Power Engineering, are given. These studies cover the next topics: double differential neutron emission cross sections (DDX), neutron-gamma coincidence experiments (n, n'γ) and neutron leakage spectra for spherical assemblies (benchmark). The paper contains description and main parameters of pulsed neutron generator KG-0.3, fast neutron time of flight spectrometer, measuring and data reduction procedures, review of experimental data. Results of experiments are compared with other data; evaluated data files BROND-2, ENDF/B6, JENDL-3; basic theoretical and transport model calculations. (author)

  2. Dose determination of 600 MeV proton irradiated specimens

    The calculation method for the experimental determination of the atomic production cross section from the γ activity measurements are presented. This method is used for the determination of some isotope production cross sections for 600 MeV proton irradition in MANET steel, copper, tungsten, gold and titanium. The results are compared with some calculation. These values are used to determine the dose of specimens irradiated in the PIREX II facility. The results are discussed in terms of the irradiation parameters. A guide for the use of the production cross section determined in the dosimetry experiment are given. (author) tabs., refs

  3. Polarization Observables in Deuteron Photodisintegration below 360 MeV

    Glister, J; Lee, B W; Gilman, R; Sarty, A J; Strauch, S; Higinbotham, D W; Piasetzky, E; Allada, K; Armstrong, W; Arrington, J; Beck, A; Benmokhtar, F; Berman, B L; Boeglin, W; Brash, E; Camsonne, A; Calarco, J; Chen, J P; Choi, Seonho; Chudakov, E; Coman, L; Craver, B; Cusanno, F; Dumas, J; Dutta, C; Feuerbach, R; Freyberger, A; Frullani, S; Garibaldi, F; Hansen, J -0; Holmstrom, T; Hyde, C E; Ibrahim, H; Ilieva, Y; de Jager, C W; Jiang, X; Jones, M K; Kang, H; Kelleher, A; Khrosinkova, E; Kuchina, E; Kumbartzki, G; LeRose, J J; Lindgren, R; Markowitz, P; Beck, S May-Tal; 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; Reyhan, M; Roche, J; Rousseau, Y; Saha, A; Sawatzky, B; Schulte, E; Shabestari, M; Shahinyan, A; Shneor, R; Sirca, 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

    2010-01-01

    High precision measurements of induced and transferred recoil proton polarization in d(polarized gamma, polarized p})n have been performed for photon energies of 277--357 MeV and theta_cm = 20 degrees -- 120 degrees. The measurements were motivated by a longstanding discrepancy between meson-baryon model calculations and data at higher energies. 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.

  4. An intense 14 MeV neutron source

    Su Tongling; Sun Biehe; Yang Baotai; Piao Yubo; Shui Yongqing; Chen Kefan; Wang Xuezhi; Yang Cheng; Niu Zhanqi; Liu Yanton; Pan Minshen; Hong Zhongti; Chen Qin (Lanzhou Univ., GS (China). Inst. of Nuclear Research)

    1990-02-15

    A 3x10{sup 12} n/s source of 14 MeV neutrons is described in this paper. The neutrons are produced by the T(d,n){sup 4}He reaction under a 30 mA, 300 keV deuteron beam bombarding a water-cooled, rotating titanium-tritide target. The size of the beam spot on the target is 1.8 cm, and at the distance of closest approach to the source a neutron flux of 5x10{sup 11} n/cm{sup 2} s is obtained. (orig.).

  5. Boeing 120 MeV RF linac for FEL research

    A new electron linac for high power, visible wavelength, free electron laser research is under construction at the Boeing Radiation Laboratory in Seattle. The linac is a five section, traveling wave, L band structure with a specialized comb pulse format of widely separated high charge micropulses. The paper describes the accelerator design and prototyping of key components of the linac. These include a double subharmonic injector and a long pulse phase and amplitude stabilized RF source which have been tested on Boeing's 20 MeV S band linac

  6. 14-MeV neutron streaming through shield gaps

    Monte Carlo calculations have been performed to determine the neutron streaming through straight and single-bend gaps for three different shield thicknesses. A uniform plane source emitting 14-MeV neutrons with a cosine angular distribution was used in the analyses. The results obtained are discussed in terms of how they might be used in the early stages of a shield design to obtain approximate solutions to design questions. These results have direct implications regarding neutron-streaming problems that will be encountered in the shielding analyses of tokamak fusion reactors which are constructed from pie-shaped shield/vacuum chamber segments

  7. Polarization observables in deuteron photodisintegration below 360 MeV

    Glister, Jacqueline; Lee, Byungwuek; Gilman, R; Sarty, Adam; Strauch, Steffen; Higinbotham, Douglas; Piasetzky, Eliazer; Allada, Kalyan; Armstrong, Whitney; Arrington, John; Beck, Arie; Benmokhtar, Fatiha; Berman, Barry; Boeglin, Werner; Brash, Edward; Camsonne, Alexandre; Calarco, John; Chen, Jian-Ping; Choi, Seonho; Chudakov, Eugene; Coman, Luminita; Craver, Brandon; Cusanno, Francesco; Dumas, Jonathan; Dutta, Chiranjib; Feuerbach, Robert; Freyberger, Arne; Frullani, Salvatore; Garibaldi, Franco; Hansen, Jens-Ole; Holmstrom, Timothy; Hyde, Charles; Ibrahim, Hassan; Ilieva, Yordanka; De Jager, Cornelis; Jiang, Xiaodong; Jones, Mark; Kang, Hoyoung; Kelleher, Aidan; Khrosinkova, Elena; Kuchina, Elena; Kumbartzki, Gerfried; LeRose, John; Lindgren, Richard; Markowitz, Pete; Beck, S. May-Tal; McCullough, Emily; Meekins, David; Meziane, Mehdi; Meziane, Zein-Eddine; Michaels, Robert; Moffit, Bryan; Norum, Blaine; Oh, Yongseok; Olson, Michael; Paolone, Michael; Paschke, Kent; Perdrisat, Charles; Potokar, Milan; Pomatsalyuk, Roman; Pomerantz, Ishay; Puckett, Andrew; Punjabi, Vina; Qian, Xin; Qiang, Yi; Ransome, Ronald; Reyhand, Meral; Roche, Julie; Rousseau, Yannick; Saha, Arunava; Sawatzky, Bradley; Schulte, Elaine; Hashemi Shabestari, Mitra; Shahinyan, Albert; Shneor, R; Sirca, Simon; Slifer, Karl; Solvignon, Patricia; Song, JeongSeog; Sparks, Rachel; Subedi, Ramesh; Urciuoli, Guido; Wang, Kebin; Wojtsekhowski, Bogdan; Yan, Xinhu; Yao, Huan; Zhan, Xiaohui

    2011-03-01

    High precision measurements of induced and transferred recoil proton polarization in d(polarized gamma, polarized p})n have been performed for photon energies of 277--357 MeV and theta_cm = 20 degrees -- 120 degrees. The measurements were motivated by a longstanding discrepancy between meson-baryon model calculations and data at higher energies. 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.

  8. neutron-proton elastic scattering between 200 and 500 MeV - 2. Measurement of Rsub(t) and Asub(t)

    The Wolfenstein parameters Rsub(t) and Asub(t) have been measured in free np elastic scattering at 220, 325, 425 and 495 MeV at 100 intervals in the centre of mass range 60 to 1600, with errors typically +- 0.05. (author)

  9. Correlations of $\\alpha$-particles in splitting of $^{12}$C nuclei by neutrons of energy of 14.1 MeV

    Kattabekov, R R; Artemenkov, D A; Bradnova, V; Zarubin, P I; Zarubina, I G; Majling, L; Rusakova, V V; Sadovsky, A B

    2014-01-01

    Correlations of $\\alpha$-particles are studied on statistics of 400 events of splitting $^{12}$C $\\rightarrow$ 3$\\alpha$ in nuclear track emulsion exposed to $14.1 MeV$ neutrons. The ranges and emission angles of the $\\alpha$-particles are measured. Distributions over energy of $\\alpha$-particle pairs and triples are obtained.

  10. Astronomical telescope for photons-gamma rays of low energy (approximately 4 MeV using the difference method like a Venetian blind

    de Aguiar, O. D.; Martin, I. M.

    1980-07-01

    A description of a gamma ray telescope, which is sensitive to photons in the energy range of 3 - 10 MeV is presented. Collimation was provided by a passive shield which functioned somewhat like a 'venetian blind' to block the signal from one of the detectors. Signal subtraction techniques were used to obtain the desired information.

  11. Undamped surface waves in the scattering of 16O + 28Si at E/sub c. m./ = 35 MeV

    The elastic scattering of 16O + 28Si at E/sub c. m./ = 35 MeV has been measured in the angular range 20degree -2. The structure at backward angles is of the form of a Legendre Polynomial (mod P/sub l 26/(costheta))2, indicating the existence of a partial-wave (orbiting) resonance

  12. Measurements of 12C(→γ,pp) photon asymmetries for Eγ= 200–450 MeV

    Robinson, J; MacGregor, I.J.D.; Annand, J. R. M.; Aguar-Bartolomé, P.; Akasoy, L. K.; Arends, H.J.(Institut für Kernphysik, University of Mainz, Mainz, D-55099, Germany); Azimov, Y. I.; Bantawa, K.(Kent State University, Kent, OH, 44242, USA); Beck, R.; Bekrenev, V. S.; H. Berghäuser; Braghieri, A.; Branford, D.; Briscoe, W. J.; Brudvik, J.

    2013-01-01

    The 12C (→γ ,pp) reaction has been studied in the photon energy range 200-450 MeV at the Mainz microtron MAMI-C, where linearly polarised photons were energy-tagged using the Glasgow-Mainz Tagged Photon Spectrometer and protons were detected in the Crystal Ball detector. The photon asymmetry Σ has been measured over a wider Eγ range than previous measurements. The strongest asymmetries were found at low missing energies where direct emission of nucleon pairs is expected. Cuts on the dif...

  13. Measurement of the (236)U(n,f) cross section from 170 MeV to 2 MeV at the CERN n_TOF Facility

    Sarmento, R. [Instituto Tecnologico e Nuclear, Sacavem, Portugal; Goncalves, I. F. [Instituto Tecnologico e Nuclear, Sacavem, Portugal; Vaz, P. [Instituto Tecnologico e Nuclear (ITN), Lisbon, Portugal; Carrapico, C. [Instituto Tecnologico e Nuclear (ITN), Lisbon, Portugal; Carrillo de Albornoz, A. [Instituto Tecnologico e Nuclear, Sacavem, Portugal; Marques, L. [Instituto Tecnologico e Nuclear, Sacavem, Portugal; Salgado, J. [Instituto Tecnologico e Nuclear, Sacavem, Portugal; Tavora, L. [Instituto Tecnologico e Nuclear, Sacavem, Portugal; Calviani, M. [CERN, Geneva, Switzerland; Andriamonje, S. [CERN, Geneva, Switzerland; Chiaveri, E. [CERN, Geneva, Switzerland; Guerrero, C. [CERN, Geneva, Switzerland; Vlachoudis, V. [CERN, Geneva, Switzerland; Colonna, N. [Instituto Nazionale di Fisica Nucleare, Bari, Italy; Barbagallo, M. [Instituto Nazionale di Fisica Nucleare, Bari, Italy; Marrone, S. [Instituto Nazionale di Fisica Nucleare, Bari, Italy; Tagliente, G. [Instituto Nazionale di Fisica Nucleare, Bari, Italy; Terlizzi, R. [Instituto Nazionale di Fisica Nucleare, Bari, Italy; Belloni, F. [Instituto Nazionale de Fisica Nucleare, Trieste, Italy; Fuji, K. [Instituto Nazionale de Fisica Nucleare, Trieste, Italy; Milazzo, P. M. [Instituto Nazionale de Fisica Nucleare, Trieste, Italy; Moreau, C. [Instituto Nazionale de Fisica Nucleare, Trieste, Italy; Alvarez-Velarde, F. [Centro de Investigaciones Energeticas Medioambientales y Technol., Madrid, Spain; Cano-Ott, D. [CIEMAT, Madrid; Gonzalez-Romero, E. [CIEMAT, Madrid; Guerrero, C. [Centro de Investigaciones Energeticas Medioambientales y Technol., Madrid, Spain; Martinez, T. [Centro de Investigaciones Energeticas Medioambientales y Technol., Madrid, Spain; Mendoza, E. [Centro de Investigaciones Energeticas Medioambientales y Technol., Madrid, Spain; Villamarin, D. [Centro de Investigaciones Energeticas Medioambientales y Technol., Madrid, Spain; Vicente, M. C. [Centro de Investigaciones Energeticas Medioambientales y Technol., Madrid, Spain; Andrzejewski, Jozef [ORNL; Karamanis, D. [University of Ioannina, Greece; Marganiec, J. [University of Lodz; Assimakopoulos, P. A. [University of Ioannina, Greece; Karadimos, D. [University of Ioannina, Greece; Papachristodoulou, C. [University of Ioannina, Greece; Patronis, N. [University of Ioannina, Greece; Audouin, L. [Universite Paris XI, Orsay, France; David, S. [CNRS, Orsay, France; Ferrant, L. [Universite Paris XI, Orsay, France; Isaev, S. [CNRS/IN2P3, Orsay, France; Stephan, C. [CNRS/IN2P3, Orsay, France; Tassan-Got, L. [CNRS/IN2P3, Orsay, France; Badurek, G. [Vienna University of Technology, Austria; Jericha, E. [Vienna University of Technology, Austria; Leeb, H. [Vienna University of Technology, Austria; Oberhummer, H. [Vienna University of Technology, Austria; Pigni, M. T. [Vienna University of Technology, Austria; Baumann, P. [CNRS, Strasbourg, France; Kerveno, M. [CNRS, Strasbourg, France; Lukic, S. [CNRS, Strasbourg, France; Rudolf, G. [CNRS, Strasbourg, France; Becvar, F. [Charles University, Prague, Czech Republic; Krticka, M. [Charles University, Prague, Czech Republic; Calvino, F. [Universidad Politecnica de Madrid, Spain; Capote, R. [International Atomic Energy Agency (IAEA); Frais-Koelbl, H. [International Atomic Energy Agency (IAEA); Griesmayer, E. [International Atomic Energy Agency (IAEA); Mengoni, A. [International Atomic Energy Agency (IAEA); Praena, J. [University of Seville; Capote, R. [University of Seville; Lozano, M. [University of Seville; Quesada, J. [University of Seville; Cennini (et al.), P. [INFN, Laboratori Nazionali di Legnaro, Italy; Chapel, V. [University of Ciombra, Portugal; Ferreira-Marques, R. [University of Ciombra, Portugal; Lindote, A. [University of Ciombra, Portugal; Lopes, I. [University of Ciombra, Portugal; Neves, F. [University of Ciombra, Portugal; et al.

    2011-01-01

    The neutron-induced fission cross section of {sup 236}U was measured at the neutron Time-of-Flight (n-TOF) facility at CERN relative to the standard {sup 235}U(n,f) cross section for neutron energies ranging from above thermal to several MeV. The measurement, covering the full range simultaneously, was performed with a fast ionization chamber, taking advantage of the high resolution of the n-TOF spectrometer. The n-TOF results confirm that the first resonance at 5.45 eV is largely overestimated in some nuclear data libraries. The resonance triplet around 1.2 keV was measured with high resolution and resonance parameters were determined with good accuracy. Resonances at high energy have also been observed and characterized and different values for the cross section are provided for the region between 10 keV and the fission threshold. The present work indicates various shortcomings of the current nuclear data libraries in the subthreshold region and provides the basis for an accurate re-evaluation of the {sup 236}U(n,f) cross section, which is of great relevance for the development of emerging or innovative nuclear reactor technologies.

  14. Total-absorption detector with CsI(Tl) crystal for measurement of gamma-quantum energies of 10-104 MeV

    A total-absorption shower scintillation gamma spectrometer is described. The spectrometer is designed for measurement of the energies of gamma quanta produced by interaction of relativistic particles with single crystals. The detector is based on a CsI(Tl) crystal, which is viewed by an FEU-49 photomultiplier operating at 660 V. The dynamic range of gamma-quantum energy measurement is 10-104 MeV. The energy resolution is 9% for gamma quanta with an energy of 4.43 MeV

  15. MeV ion beam deformation of colloidal silica particles

    Spherical sub-micrometer-sized silica particles were prepared by the Stoeber process, from a reaction mixture containing tetraethoxysilane, ammonia and ethanol, and deposited into silicon wafers. The samples were then irradiated at room temperature with 4 MeV Si, Ti, Pt or Au ions at a fluence of 4 x 1015 ions/cm2, under an angle of 49o with respect to the sample surface. The size, size distribution and shape of the silica particles were determined using scanning electron microscopy (SEM) and atomic force microscopy (AFM). After the irradiation the spherical silica particles can be 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 depends on the electronic stopping power of the impinging ion. For the series of 4 MeV ions we used in this work a relative transverse diameter change of 17% per 1 keV/nm was obtained and it seems that no threshold for the electronic energy loss exists

  16. Advantages and limits of 14-MeV neutron radiography

    Brzosko, J.S. (Istituto Avogadro di Tecnologia, S.R.L., Ravenna (Italy) Stevens Inst. of Tech., Hoboken, NJ (United States)); Robouch, B.V. (Ass. EURATOM-ENEA, Centro Ricerche Energie, Frascati (Italy)); Ingrosso, L. (Avogadro Energy Systems Inc., New York (United States)); Bortolotti, A. (Ferrara Univ. (Italy)); Nardi, V. (Stevens Inst. of Tech., Hoboken, NJ (United States) Ferrara Univ. (Italy))

    1992-10-01

    The paper evaluates the potentials of fast-neutron radiography (FNR) for the inspection of bulky, solid objects. Data for both a fast (E[sub n] = 14.7 MeV) and a slow (E[sub n] = 0.1 eV) neutron source are compared. The reproduction of images consists of Monte Carlo simulations of (a) the neutron random walk in a slab (iron, SiC ceramic, and polyethelene (CH[sub 2])[sub n] plastic) with a void, (b) the process of neutron recording in a detector, and (c) a print-out of images. For a general analysis, 3D-MCSC-RWR software operates without simplification of either the FNR design or the nuclear data files. The results first show the feasibility of the use of 14-MeV neutron radiography, then the superiority of FNR over slow-neutron radiography in-the-field when the thickness of the full slab is over 1 cm and requires a resolution better than 0.1 mm. Examples of some numerically simulated images as well as FNR scaling functions are shown. A review of the available fast-neutron sources reveals that only plasma-focus machines would simultaneously meet all FNR requirements: Y[sub n] [>=] 10[sup 13] n/pulse, small-source dimensions and mobility.

  17. Advantages and limits of 14-MeV neutron radiography

    The paper evaluates the potentials of fast-neutron radiography (FNR) for the inspection of bulky, solid objects. Data for both a fast (En = 14.7 MeV) and a slow (En = 0.1 eV) neutron source are compared. The reproduction of images consists of Monte Carlo simulations of (a) the neutron random walk in a slab (iron, SiC ceramic, and polyethelene (CH2)n plastic) with a void, (b) the process of neutron recording in a detector, and (c) a print-out of images. For a general analysis, 3D-MCSC-RWR software operates without simplification of either the FNR design or the nuclear data files. The results first show the feasibility of the use of 14-MeV neutron radiography, then the superiority of FNR over slow-neutron radiography in-the-field when the thickness of the full slab is over 1 cm and requires a resolution better than 0.1 mm. Examples of some numerically simulated images as well as FNR scaling functions are shown. A review of the available fast-neutron sources reveals that only plasma-focus machines would simultaneously meet all FNR requirements: Yn ≥ 1013 n/pulse, small-source dimensions and mobility

  18. Upgrading the Linac 400 MeV Switchyard

    This note describes changes in the 400 MeV beam transfer system from the Linac to improve the quality of the beam delivered to the Booster and to add the capability to direct beam to the MuCool Test Area (MTA). The new configuration has two pairs of pulsed dipole magnets on each side of the 400 MeV electrostatic Chopper. The smaller pair deflects vertically to replace the kick of the Chopper to send the beam to the Booster while the larger pair deflects horizontally to transfer the beam to the MTA. In this new scheme, the Chopper is uncharged while the beam is injected into the Booster such that the injection position does not rely on Chopper power supply regulation as it does now. A feature of the proposed upgrade is that no changes in the lattice functions are required in the lines to the Booster or to the Dump; once the four new magnets are installed, the switch between the old and new operating modes can be done from upstairs. The transfer to the MTA is already described in a previous note

  19. First Light: MeV Astrophysics from the Moon

    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.

  20. Angular spreading measurements using MeV ion microscopes

    Whitlow, Harry J., E-mail: harry.whitlow@he-arc.ch [Institut des Microtechnologies Appliquées, Haute Ecole Arc Ingénierie, Eplatures-Gris 17, CH-2300 La Chaux-de-Fonds (Switzerland); Department of Physics, P.O. Box 35 (YFL), FI-40014 University of Jyväskylä (Finland); Ren, Minqin; Chen, Xiao; Osipowicz, Thomas; Kan, Jeroen A. van; Watt, Frank [Centre for Ion Beam Applications, National University of Singapore (Singapore)

    2013-07-01

    The sharpness of MeV ion microscope images is governed by small-angle scattering and associated lateral spreading of the ion beam in the sample. We have investigated measurement of the half-angle of the angular spreading distribution by characterising the image blurring in direct-Scanning Transmission Ion Microscopy (direct-STIM). In these tests Mylar™ foils of 0.5–6 μm were used to induce angular spreading. Images were taken of an electron microscope grid using 2 MeV protons with, and without, the foils in the beam path. The blurring was measured by fitting the width of a circular Gaussian point spread function to the images with and without the foil in position. The results show the half-angle width of the spreading has a square root dependence on foil thickness that lies intermediate between SRIM predictions and the theoretical estimates (Bird and Williams fits to the Sigmund and Winterbon data and Amsel et al.)

  1. Development of MeV cluster ion beams and irradiation effects

    Saito, Yuichi; Mizuhashi, Kiyoshi; Tajima, Satoshi; Arakawa, Kazuo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Hirata, Kouichi; Kobayashi, Yoshinori [National Inst. of Materials and Chemical Research, Tsukuba, Ibaraki (Japan)

    2001-02-01

    The production and acceleration of cluster ion beams were developed by using a sputtering ion source and a tandem accelerator. Molecular beams of iron oxides were produced from Fe{sub 2}O{sub 3} powder prepared as the specimen of the ion source and accelerated to energy of MeV range. Defect densities in silicon and polycarbonate targets by irradiation were compared between monoatomic carbon ions and carbon cluster beams (C{sub 2}-C{sub 4}). Beam currents by injection of carbon cluster beams (C{sub 8}) were measured for various targets such as Si, Al, Al{sub 2}O{sub 3} and polycarbonate. The target and time dependence of the beam currents were originated from sputtered ions due to water molecules and oxides adhered at the surface of the targets. (Y. Kazumata)

  2. TEM observations of radiation damage in tungsten irradiated by 20 MeV W ions

    Ciupiński, Ł., E-mail: lciupinski@gmail.com [Warsaw University of Technology, ul. Woloska 141, PL-02507 Warsaw (Poland); Ogorodnikova, O.V. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Płociński, T.; Andrzejczuk, M.; Rasiński, M. [Warsaw University of Technology, ul. Woloska 141, PL-02507 Warsaw (Poland); Mayer, M. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Kurzydłowski, K.J. [Warsaw University of Technology, ul. Woloska 141, PL-02507 Warsaw (Poland)

    2013-12-15

    Polycrystalline, recrystallized W targets were subjected to implantation with 20 MeV W{sup 6+} ions in order to simulate radiation damage caused by fusion neutrons. Three samples with cumulative damage of 0.01, 0.1 and 0.89 dpa were produced. The near-surface zone of each sample has been analyzed by transmission electron microscopy (TEM). To this end, lamellae oriented perpendicularly to the targets implanted surface were milled out using focused ion beam (FIB). A reference lamella from non-irradiated, recrystallized W target was also prepared to estimate the damage introduced during FIB processing. TEM studies revealed a complex microstructure of the damaged zones as well as its evolution with cumulative damage level. The experimentally observed damage depth agrees very well with the one calculated using the Stopping and Range of Ions in Matter (SRIM) software.

  3. Reaction mechanisms of fast neutrons on stable Mo isotopes below 21 MeV

    Reimer, P.; Avrigeanu, V.; Chuvaev, S. V.; Filatenkov, A. A.; Glodarin, T.; de Koning, A; Plompen, A. J. M.; Qaim, S. M.; Smith, D. L.; Weigmann, H.

    2005-01-01

    A large number of new measurements with the activation technique were performed for (n,2n) and neutron-induced Delta Z=1,2 reaction cross sections on the stable molybdenum isotopes in the energy range from 13.5 to 21 MeV. First results were obtained for the Mo-92(n,2n)Mo-91(m),Mo-92(n,alpha)Zr-89(m),Mo-94(n,2n)Mo-93(m),Mo-95(n,p)Nb-95(m),Mo-96(n,p)Nb-96,Mo-96(n,x)Nb-95(m), Mo-97(n,p)Nb-97, Mo-97(n,p)Nb-97(m), Mo-97(n,x)Nb-96, Mo-98(n,p)Nb-98(m), Mo-98(n,x)Nb-97, Mo-98(n,x)Nb-97(m), and Mo-100...

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

    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

  5. Pion scattering from polarized 15N at Tπ=164 MeV

    The analyzing power Ay was measured for π+endash 15 rvec N elastic scattering at Tπ=164 MeV between 40 degree and 100 degree using a polarized 15NH3 target. Within the statistical accuracy of the data Ay(θ) 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. Physical and chemical response of 70 MeV carbon ion irradiated Kapton-H polymer

    H S Virk; P S Chandi; A K Srivastava

    2001-10-01

    Physical and chemical responses of 70 MeV carbon ion irradiated Kapton-H polymer were studied by using UV-visible, FTIR and XRD techniques. The ion fluences ranging from 9.3 × 1011–9 × 1013 ions cm–2 were used. Recorded UV-visible spectra clearly showed a decrease in absorption initially with fluence, but for the higher fluences it showed a recovery characteristic. A decrease in band-gap energy of 0.07 eV was observed. The FTIR analysis indicated the high resistance to radiation induced degradation of polymer. The diffraction pattern of Kapton-H indicates that this polymer is semi-crystalline in its nature. In case of irradiated one, there was an average increase of crystallite size by 20%, but diffuse pattern indicates that there was a decrease in crystallinity, which may be attributed to the formation of complex structure induced by the cross-linking of the polymeric chains.

  7. Radiation vulcanization of natural rubber latex with 3 MeV electron beams, 1

    The sensitized radiation vulcanization of natural rubber latex has been carried out with a 3 MeV, 25 mA Dynamitron electron accelerator. Latex was irradiated over a range of dose rate from 0.3 to 60 kGy/sec in the presence of sensitizers such as n-butyl acrylate, 2-ethylhexyl acrylate, and 1,6-hexanediol diacrylate. The sensitized vulcanization of NR latex with electron beams is greatly affected by dose rate. The vulcanization dose increases with increasing dose rate. The maximum tensile strength of rubber films from the irradiated latex decreases slightly with increasing dose rate. There is negligible effect of dose rate on the viscosity of the irradiated latex. (author)

  8. Intercomparison exercise with MeV neutrons using various electronic personal dosimeters

    Electronic personal neutron dosimeters developed at GSF, PTB, and LMU, were exposed with mono-energetic neutrons at the PTB neutron irradiation facility in Braunschweig, Germany. The neutron energies used ranged from 1.5 to 4.1 MeV. The doses measured by each dosimeter were compared to each other and to the Saphydose-n dosimeter that is commercially available. All dosimeters were calibrated based on either 252Cf and/or 241Am-Be neutron sources or a 60Co secondary standard reference field. The doses measured were compared to estimates of reference values based on a long counter. Generally, all dosimeters produced reasonable results, given the uncertainties involved. It was noticed that the dosimeter responses show slight dependencies on energy. The corresponding differences are summarised and discussed

  9. 150 MeV Nickel ion beam irradiation effects on polytetrafluoroethylene (PTFE) polymer

    Polytetrafluoroethylene (PTFE) films were irradiated under vacuum and at room temperature with 150 MeV Ni11+ ions and fluences ranging from 5 x 1010 to 5 x 1012 ions/cm2. Ion induced modifications in optical, chemical and structural properties were studied by means of Fourier transform infrared (FTIR) spectroscopy, UV-vis spectroscopy and X-ray diffractometer (XRD). FTIR analysis indicated the defluorination of the PTFE due to the rupture of C-C and C-F bonds. UV-vis measurements indicated the decrease in the band gap Eg of pristine sample from 2.16 to 1.73 eV at a highest fluence of 5 x 1012 ions/cm2. The diffraction pattern of PTFE revealed an increase in the crystallinity at lower fluences while it decreased as the ion fluence was increased.

  10. Dislocation Climb Sources Activated by 1 MeV Electron Irradiation of Copper-Nickel Alloys

    Barlow, P.; Leffers, Torben

    1977-01-01

    irradiation temperatures corresponding to the highest source densities is approximately 350°–500°C. The climb sources are not related to any pre-existing dislocations resolved in the microscope. The sources emit three types of loop: ‘rectangular’ loops with a100 Burgers vector and {100} habit plane, normal...... prismatic loops with Burgers vector a/2110, and Frank loops. There is no significant difference between the apparent activation energy for growth of the three types of loops. The source points are suggested to be submicroscopic nickel precipitates-with reference to the existing evidence that......Climb sources emitting dislocation loops are observed in Cu-Ni alloys during irradiation with 1 MeV electrons in a high voltage electron microscope. High source densities are found in alloys containing 5, 10 and 20% Ni, but sources are also observed in alloys containing 1 and 2% Ni. The range of...

  11. (p,pα) cluster-knockout reaction on 9Be at 200 MeV

    The (p,pα) cluster-knockout reaction on 9Be has been investigated experimentally at a bombarding energy of 200 MeV. Coincident data were obtained at five quasifree angle pairs for proton angles ranging from 40 degree to 80 degree. The data were analyzed in terms of the distorted-wave impulse approximation. The calculated energy-sharing distributions reproduce the data reasonably well, indicating that the quasifree-knockout mechanism dominates the reaction. The factorization approximation employed in the calculation is found to be valid. The absolute spectroscopic factors derived from the data are in excellent agreement with lower-energy results, and compare well with shell-model predictions

  12. A test of charge symmetry in n-p scattering at En=183 MeV

    Measurements of the spin-dependent left-right asymmetries for n-p elastic scattering at En = 183 MeV have been obtained by scattering polarized neutrons from polarized protons. If charge symmetry holds in the n-p system, the two analyzing powers An and Ap must be equal. Our preliminary experimental result for the average value of An-Ap in the range 82.2deg ≤ θcm ≤ 116.1deg is (32.1 ± 6.1 ± 6)x10-4 where the first error is the statistical uncertainty and the second is the systematic uncertainty. This result provides clear evidence of charge symmetry breaking in the nuclear force, and agrees well with meson-exchange predictions based on the Bonn nucleon-nucleon potential. (orig.)

  13. Total cross section for p-d breakup below 30 MeV

    Kievsky, A; Viviani, M

    2000-01-01

    The total cross section for p-d breakup is studied in terms of the elastic S-matrix through the unitary condition. Calculations using the complex Kohn variational method along with the Pair Correlated Hyperspherical Harmonic basis are presented. The results have been restricted to energies below Ep=30 MeV where Coulomb effects are expected to be sizable and are compared to the existing data. Two different measurements have been found in the literature: 40 years ago, Gibbons and Macklin (1959); and 26 years ago, Carlosn et al. (1973). The calculations are found to be in reasonable agreement with these old data, though a discrepancy is observed near the deuteron breakup threshold. Moreover, a detailed analysis of the contributions to the observable from different partial waves has been presented. Unexpectedly, the main contribution for a wide range of energies has been detected in the J=3/2- state.

  14. 520 MeV proton irradiation effects on GaAs/Ge space solar cells

    Wang Rong; Guo Zeng Liang; Zhang Xin; Zhai Zuo Xu

    2002-01-01

    High-energy proton irradiation effects on GaAs/Ge solar cells for space use are studied. The cells are irradiated by protons with an energy of 5-20 MeV up to a fluence ranging from 1 x 10 sup 9 to 7 x 10 sup 1 sup 3 cm sup - sup 2 , and then the change of the photovoltaic performances is measured at AMO. It is shown that the performances of the cells keep no change under 1 x 10 sup 9 cm sup - sup 2 irradiation. Above 1 x 10 sup 9 cm sup - sup 2 irradiation, I sub s sub c , V sub o sub c and P sub m sub a sub x degrade, as proton irradiation fluence increases. But the higher the proton energy, the less the degradation of I sub s sub c , V sub o sub c and P sub m sub a sub x

  15. Structural evolution of Co/Cu nanostructures under 1 MeV ion-beam irradiation

    Co/Cu multilayers with composition wavelength ranging from 2 to 10 nm have been deposited and irradiated at various doses from 1x1014 to 3x1016 ions/cm2 using 1 MeV Si+ ions. The ion-beam-induced variation in structural properties such as interfacial mixing, interface roughness, crystallographic texture, and grain size, are characterized by a variety of x-ray scattering techniques. Irradiating Co/Cu multilayers generate metastable Co-Cu alloys whose electrical and magnetic properties have been found to be very similar to the Co-Cu alloys fabricated by other nonequilibrium methods. Fitting to the low-angle x-ray reflectivity spectra using a standard optical model yields a mixing efficiency comparable to the prediction of a ballistic ion-beam mixing model, and interfacial mixing widths consistent with the values estimated from saturation magnetization measurements

  16. Mutation effect of MeV protons on bioflocculant bacteria Bacillus cereus

    A 3.2 MeV proton beam was used to irradiate bioflocculant bacteria (Bacillus cereus) to achieve mutation. The ion fluence ranged from 1011 to 1014/cm2. Most of the bacteria were killed when the ion fluence reached 1012 ions/cm2. The survival ratio drops in an exponential way on further increasing the ion fluence. The flocculating activity of 7 samples out of 51 showed a positive change, and a perfect mutant C7-23 with a stable high capacity of bioflocculant production was found. RAPD measurements showed that a new lane appears in this sample. The flocculating activity of the C7-23 bacteria increased by factors of 22%, 54% and 217% under pH values of 4, 7 or 10, respectively

  17. Mutation effect of MeV protons on bioflocculant bacteria Bacillus cereus

    Yang, Y. N.; Ren, N.; Xue, J. M.; Yang, J.; Rong, B. L.

    2007-09-01

    A 3.2 MeV proton beam was used to irradiate bioflocculant bacteria (Bacillus cereus) to achieve mutation. The ion fluence ranged from 1011 to 1014/cm2. Most of the bacteria were killed when the ion fluence reached 1012 ions/cm2. The survival ratio drops in an exponential way on further increasing the ion fluence. The flocculating activity of 7 samples out of 51 showed a positive change, and a perfect mutant C7-23 with a stable high capacity of bioflocculant production was found. RAPD measurements showed that a new lane appears in this sample. The flocculating activity of the C7-23 bacteria increased by factors of 22%, 54% and 217% under pH values of 4, 7 or 10, respectively.

  18. Disintegration of {sup 12}C nuclei by 700–1500 MeV photons

    Nedorezov, V. [Institute for Nuclear Research, Russian Academy of Sciences, Prospekt 60-letiya Oktyabrya 7a, 117312 Moscow (Russian Federation); D' Angelo, A.; Bartalini, O. [Dipartimento di Fisica – Università degli Studi di Roma “Tor Vergata”, via della Ricerca Scientifica 1, I-00133 Roma (Italy); INFN – Sezione di Roma “Tor Vergata”, via della Ricerca Scientifica 1, I-00133 Roma (Italy); Bellini, V. [Dipartimento di Fisica – Università degli Studi di Catania, via Santa Sofia 64, I-95123 Catania (Italy); INFN – Sezione di Catania, via Santa Sofia 64, I-95123 Catania (Italy); Capogni, M. [Dipartimento di Fisica – Università degli Studi di Roma “Tor Vergata”, via della Ricerca Scientifica 1, I-00133 Roma (Italy); INFN – Sezione di Roma “Tor Vergata”, via della Ricerca Scientifica 1, I-00133 Roma (Italy); Casano, L.E. [INFN – Sezione di Roma “Tor Vergata”, via della Ricerca Scientifica 1, I-00133 Roma (Italy); Castoldi, M. [Dipartimento di Fisica – Università degli Studi di Genova, via Dodecaneso 33, I-16146 Genova (Italy); Curciarello, F.; De Leo, V. [Dipartimento di Fisica e di Scienze della Terra, Università di Messina, salita Sperone 31, I-98166 Messina (Italy); INFN – Sezione di Catania, via Santa Sofia 64, I-95123 Catania (Italy); Didelez, J.-P. [IN2P3, Institut de Physique Nucléaire, Rue Georges Clemenceau, F-91406 Orsay (France); and others

    2015-08-15

    Disintegration of {sup 12}C nuclei by tagged photons of 700–1500 MeV energy at the GRAAL facility has been studied by means of the LAGRANγE detector with a wide angular acceptance. The energy and momentum distributions of produced neutrons and protons as well as their multiplicity distributions were measured and compared with corresponding distributions calculated with the RELDIS model based on the intranuclear cascade and Fermi break-up models. It was found that eight fragments are created on average once per about 100 disintegration events, while a complete fragmentation of {sup 12}C into 12 nucleons is observed typically only once per 2000 events. Measured multiplicity distributions of produced fragments are well described by the model. The measured total photoabsorption cross section on {sup 12}C in the same energy range is also reported.

  19. Ion shaking in the 200 MeV XLS-ring

    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 H2 to CO2) bounce frequencies in the ring (1--10 MHz). The response of the beam size, vertical betatron tune and lifetime was studied

  20. Ion shaking in the 200 MeV XLS-ring

    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.

  1. Ion shaking in the 200 MeV XLS-ring

    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.

  2. Ion shaking in the 200 MeV XLS-ring

    Bozoki, E.; Kramer, S. L.

    1992-03-01

    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 H2 to CO2) bounce frequencies in the ring (1-10 MHz). The response of the beam size, vertical betatron tune, and lifetime was studied.

  3. Capacitance-voltage investigation of silicon photodiodes damaged by MeV energy light ions

    Complete text of publication follows. Nuclear radiation creates not only deep centers, but in addition influences shallow dopant concentration in semiconductors, as well. At a given temperature the maximum frequency a center can respond to depends on its energy level, therefore the capacitance-voltage (C-V) characteristics of radiation damaged semiconductor diodes should ideally be measured as function of frequency in order to obtain the physical and energy depth distribution of ionized centers [1,2]. In our experiments C-V plots of MeV energy ion irradiated photodiodes were taken at fixed 1 kHz frequency, which is low enough to be sensitive at room temperature to some of the deep levels expected. During, for example, an irradiation with 5.5 MeV α particles the capacitance of a p+nn+ diode increased significantly at low voltages, but showed rather small changes at higher ones. The former turned out to be merely related to a decrease of the built in voltage, corresponding to a lifetime to relaxation type transition of the semiconductor [3]. Rescaling C-V data for this change, the remaining, actual capacitance changes could be interpreted as related to nuclear recoil caused damage located around the end of particle tracks. C-V technique has also been used for follow up investigation of spontaneous self annealing at room temperature of irradiated samples. This is shown here by plotting capacitance data normalized to their virgin values as function of depletion depth for irradiation with 430 keV protons, whose range is about 5 μm. The sensitivity of the method is illustrated for low fluence of 6.5 MeV oxygen, whose range is 5 μm, too, and where the normalization is now made to data taken one week after the irradiation. Acknowledgement This work was supported by the Hungarian Research and Technology Innovation Fund and the Croatian Ministry of Science, Education and Sports within the framework of the Hungarian-Croatian Intergovernmental Science and Technology Co

  4. Vector and tensor analyzing powers in the 208Pb(vector d,t)207Pb reaction at 200 and 360 MeV

    Cross-sections, vector and tensor analyzing powers for the main levels in 207Pb have been measured via the 208Pb (d,t) 207Pb reaction at 200 and 360 MeV incident energies. Ay and Ayy spin observables allow a clear identification of the valence levels, especially at 200 MeV. The results are compared with finite range DWBA calculations using the Paris projectile-ejectile form factor including the S and D components. The analysis shows a large effect of the D component on the tensor analyzing powers at the most forward angles. At both energies, the spin part of the deuteron optical potential is very important to describe the analyzing powers and especially Ayy. The good description of all observables at 200 MeV allows this reaction to be used as a spectroscopic tool

  5. Fissility of Bi, Pb, Au, Pt, W, Ta, V, and Ti nuclei measured with 100 MeV compton back-scattered photons

    Photofission cross sections of 209 Bi, nat Pb, 197 Au, nat Pt, nat W, 181 Ta, 51 V, and nat Ti nuclei have been measured at an incident photon energy of 100 MeV using monochromatic photons produced by Compton backscattering at the ROKK-1M facility (BINP, Novosibirsk). Detection of fission fragments has been performed by means of Makrofol track-etch detectors in close contact with metallic foils of the target elements. The values of fissility at 100 MeV deduced for the targets under investigation are found to range between 10-4 and 10-2. The present results show consistency with the fissility trends calculated for 69- and 600-MeV monoenergetic photons using a formalism based on the current two-step model for intermediate-energy photofission reactions. (author). 39 refs., 4 figs., 3 tabs

  6. Multistep direct mechanism in the (p-vector,3He) inclusive reaction on 59Co and 93Nb at incident energies between 100 and 160 MeV

    Emission-energy distributions for cross sections as well as analyzing powers were investigated for (p-vector,3He) reactions on 59Co and 93Nb to the continuum from a threshold of ∼40 MeV up to the kinematic limit at incident energies of 130 and 160 MeV. A range of scattering angles from 15 degree sign to 140 deg. (laboratory) was explored. The experimental distributions were compared with a multistep direct theory in which a reaction mechanism based on deuteron pickup is employed. Reasonable agreement between experimental double differential cross sections and analyzing powers and the theoretical expectation was obtained. This work, together with published results for the same reaction and targets at a lower projectile energy of 100 MeV, allowed the incident-energy dependence of the cross section and analyzing power distributions to be explored

  7. Simultaneous quiet time observations of energetic radiation belt protons and helium ions - The equatorial alpha/p ratio near 1 MeV

    Fritz, T. A.; Spjeldvik, W. N.

    1979-01-01

    Simultaneous monitoring of energetic helium ions and protons in the earth's radiation belts has been conducted with Explorer 45 in the immediate vicinity of the equatorial plane. Protons were measured from less than 1 keV to 1.6 MeV and also above 3.3 MeV in a channel responsive up to 22 MeV; helium ions were monitored in three passbands: 910 keV to 3.15 MeV, 590 to 910 keV, and 2.0 to 3.99 MeV. Alpha/proton flux ratios were found to vary significantly with energy and location in the radiation belts. At equal energy per nucleon a range of variability for alpha/p from 0.0001 to well above 0.001 was found, and at equal energy per ion the corresponding variability was from 0.001 to above 10. The latter findings emphasize the relative importance of the very energetic helium ions in the overall radiation belt ion populations.

  8. Determination of the 233Pa(n, f) reaction cross-section from 10.5 to 16.5 MeV neutron energy by surrogate ratio method

    In the present work, we have employed surrogate ratio method to derive 233Pa(n,f) cross sections from the measurement of the ratio of the fission decay probabilities of 234Pa and 236U compound systems at same excitation energy over the excitation energy range of 16.0 MeV to 22.0 MeV, that are formed in 232Th(6Li, α)-234Pa and 232Th(6Li, d)-236U transfer reactions

  9. High-resolution Auger spectroscopy on 79 MeV Ar5+, 89 MeV Ar6+, and 136 MeV Ar7+ ions after excitation by helium

    In this thesis the atomic structure of highly excited Ar6+ and Ar7+ ions was studied. For this 79 MeV Ar5+, 89 MeV Ar6+, and 136 MeV Ar7+ ions of a heavy ion accelerator were excited by a He gas target to autoionizing states and the Auger electrons emitted in the decay were measured in highly-resolving state. The spectra were taken under an observational angle of zero degree relative to the beam axis in order to minimize the kinematical broadening of the Auger lines. (orig./HSI)

  10. Degradation of micromorph silicon solar cells after exposure to 65 MeV protons

    Neitzert, Heinz-Christoph [DIIIE, Salerno University, Fisciano (Italy); NanoMates, Salerno University, Fisciano (Italy); Labonia, Laura; Citro, Michele [DIIIE, Salerno University, Fisciano (Italy); Delli Veneri, Paola; Mercaldo, Lucia [ENEA Portici Research Center (Italy)

    2010-04-15

    Silicon micromorph tandem solar cells, grown on commercial TCO coated substrates by plasma enhanced chemical vapour deposition, with an initial efficiency higher than 10%, have been degraded, in order to check their stability under space conditions, by irradiation with 65 MeV protons with fluences ranging from 10{sup 12}protons/cm{sup 2} up to 10{sup 14}protons/cm{sup 2}. For low proton fluences we find a stronger decrease of the top amorphous cell photocurrent due to the stronger impact of the proton beam on the glass substrate transparency in the visible wavelength range, as compared to the infrared range. Only for very high fluences a stronger degradation of the photocurrent in the infrared wavelength range where the bottom microcrystalline cell is dominating the spectral response, has been observed. Because the non-irradiated cell has been found to be spectrally mismatched in favour of the top amorphous cell under AM1.5 and even more under AM0 irradiation conditions, for low and intermediate fluences the irradiation decreases the spectral mismatch of the micromorph tandem cells and results consequently in a relative stabilization of the irradiation induced degradation. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Elastic scattering for 16O + 12C at 140 MeV and 218 MeV

    In this work, angular distribution of cross sections have been measured for 12C(16O,16O)12C at two energies. The measurements were carried out in 0.50 intervals between 50-19.50C (lab.) at 140 MeV, 4.50-14.50 at 218 MeV. An optical model analysis of these strong structure angular distributions was done. Good fits of the data were obtained using the optical model search code GENOA with a full Woods-Saxon potential form. This yielded parameters subject to considerable ambiguities as it is known to occur for strongly absorbed particles. These ambiguities were explored in detail and it was found that both the real and the imaginary parts present some characteristics that have been found before for the real potential (as Igo relation for continous ambiguities and the fact that potentials with different diffusivities tend to have the same value at the strong absorption radii). It was found, among other results, that the real volume integral, the mean square radius, as well as the total reaction cross section (σsub(r)) cannot be determined unambiguously. A strong correlation was found between σsub(r) and the imaginary diffusivity. A systematic study of how the variation of the potential parameters affects the angular distribution is presented and some features of the diffraction structure of the angular distribution are discussed. (author)

  12. A Monte Carlo comparison of PGNAA system performance using 252Cf neutrons, 2.8-MeV neutrons and 14-MeV neutrons

    Naqvi, A. A.

    2003-10-01

    Monte Carlo simulations were carried out to compare performance of a 252Cf neutron and a 14-MeV neutron-based prompt γ-ray neutron activation analysis (PGNAA) system with that of the 2.8-MeV neutron-based PGNAA system at King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia. Since the energy of neutron beam used in the KFUPM PGNAA system is very close to that produced by a DD neutron generator, performance comparison between a DD and a DT neutron generator-based PGNAA system is highly desired. For the sake of comparison, the calculations were carried out for the PGNAA system with geometry similar to the KFUPM PGNAA system. These calculations were required to determine improvement in performance of the KFUPM PGNAA system if its 2.8-MeV neutron source is replaced by a 252Cf neutron source or a 14-MeV neutron source. Results of the calculations revealed that the geometry of the 252Cf neutron and the 2.8-MeV neutron-based PGNAA system are not significantly different but the geometry of the 14-MeV neutron-based system is significantly different from that of the 2.8-MeV neutron-based PGNAA system. Accordingly, the prompt γ-ray yields from the 252Cf neutron and the 2.8-MeV neutron-based PGNAA system is comparable but prompt γ-ray yields from 14-MeV neutron-based PGNAA system are about three times smaller than that from the 2.8-MeV neutron-based PGNAA system. This study has shown that performance of the 252Cf neutron-based PGNAA system is comparable with that of the 2.8-MeV neutron-based PGNAA system but the performance of the 14-MeV neutron-based PGNAA system is poorer than that of the 2.8-MeV neutron-based PGNAA system.

  13. A Monte Carlo comparison of PGNAA system performance using {sup 252}Cf neutrons, 2.8-MeV neutrons and 14-MeV neutrons

    Naqvi, A.A. E-mail: aanaqvi@kfupm.edu.sa

    2003-10-01

    Monte Carlo simulations were carried out to compare performance of a {sup 252}Cf neutron and a 14-MeV neutron-based prompt {gamma}-ray neutron activation analysis (PGNAA) system with that of the 2.8-MeV neutron-based PGNAA system at King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia. Since the energy of neutron beam used in the KFUPM PGNAA system is very close to that produced by a DD neutron generator, performance comparison between a DD and a DT neutron generator-based PGNAA system is highly desired. For the sake of comparison, the calculations were carried out for the PGNAA system with geometry similar to the KFUPM PGNAA system. These calculations were required to determine improvement in performance of the KFUPM PGNAA system if its 2.8-MeV neutron source is replaced by a {sup 252}Cf neutron source or a 14-MeV neutron source. Results of the calculations revealed that the geometry of the {sup 252}Cf neutron and the 2.8-MeV neutron-based PGNAA system are not significantly different but the geometry of the 14-MeV neutron-based system is significantly different from that of the 2.8-MeV neutron-based PGNAA system. Accordingly, the prompt {gamma}-ray yields from the {sup 252}Cf neutron and the 2.8-MeV neutron-based PGNAA system is comparable but prompt {gamma}-ray yields from 14-MeV neutron-based PGNAA system are about three times smaller than that from the 2.8-MeV neutron-based PGNAA system. This study has shown that performance of the {sup 252}Cf neutron-based PGNAA system is comparable with that of the 2.8-MeV neutron-based PGNAA system but the performance of the 14-MeV neutron-based PGNAA system is poorer than that of the 2.8-MeV neutron-based PGNAA system.

  14. Scintillation response of Ce-doped or intrinsic scintillating crystals in the range up to 1 MeV

    Mareš, Jiří A.; Beitlerová, Alena; Nikl, Martin; Solovieva, Natalia; D´Ambrosio, C.; Blažek, K.; Malý, P.; Nejezchleb, K.; De Notaristefani, F.

    2004-01-01

    Roč. 38, - (2004), s. 353-357. ISSN 1350-4487 R&D Projects: GA MŠk(CZ) ME 462 Grant ostatní: NATO SfP(XX) 973510 Institutional research plan: CEZ:AV0Z1010914 Keywords : scintillation * Ce-doped scintillators * photoelectron and light yields * intrinsic and extrinsic scintillators Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.664, year: 2004

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

    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%.

  16. Accurate transport simulation of electron tracks in the energy range 1 keV-4 MeV

    Cobut, V. E-mail: vincent.cobut@chim.u-cergy.fr; Cirioni, L.; Patau, J.P

    2004-01-01

    Multipurpose electron transport simulation codes are widely used in the fields of radiation protection and dosimetry. Broadly based on multiple scattering theories and continuous energy loss stopping powers with some mechanism taking straggling into account, they give reliable answers to many problems. However they may be unsuitable in some specific situations. In fact, many of them are not able to accurately describe particle transport through very thin slabs and/or in high atomic number materials, or also when knowledge of high-resolution depth dose distributions is required. To circumvent these deficiencies, we developed a Monte Carlo code simulating each interaction along electron tracks. Gas phase elastic cross sections are corrected to take into account solid state effects. Inelastic interactions are described within the framework of the Martinez et al. [J. Appl. Phys. 67 (1990) 2955] theory intended to deal with energy deposition in both condensed insulators and conductors. The model described in this paper is validated for some materials as aluminium and silicon, encountered in spectrometric and dosimetric devices. Comparisons with experimental, theoretical and other simulation results are made for angular distributions and energy spectra of transmitted electrons through slabs of different thicknesses and for depth energy distributions in semi-infinite media. These comparisons are quite satisfactory.

  17. 160 MeV laser-accelerated protons from CH2 nano-targets for proton cancer therapy

    Hegelich, B M; Albright, B J; Cheung, M; Dromey, B; Gautier, D C; Hamilton, C; Letzring, S; Munchhausen, R; Palaniyappan, S; Shah, R; Wu, H -C; Yin, L; Fernández, J C

    2013-01-01

    Proton (and ion) cancer therapy has proven to be an extremely effective even supe-rior method of treatment for some tumors 1-4. A major problem, however, lies in the cost of the particle accelerator facilities; high procurement costs severely limit the availability of ion radiation therapy, with only ~26 centers worldwide. Moreover, high operating costs often prevent economic operation without state subsidies and have led to a shutdown of existing facilities 5,6. Laser-accelerated proton and ion beams have long been thought of as a way out of this dilemma, with the potential to provide the required ion beams at lower cost and smaller facility footprint 7-14. The biggest challenge has been the achievement of sufficient particle energy for therapy, in the 150-250 MeV range for protons 15,16. For the last decade, the maximum exper-imentally observed energy of laser-accelerated protons has remained at ~60 MeV 17. Here we the experimental demonstration of laser-accelerated protons to energies exceeding 150 MeV, re...

  18. MeV gold irradiation induced damage in α-quartz: Competition between nuclear and electronic stopping

    Damage creation in crystalline α-quartz by irradiation is studied using gold ions of energies between 0.5 and 10 MeV. For all ions, the total stopping power (dE/dx)tot has a value of about 4.5 keV/nm, whereas the contribution of the electronic stopping power ranges from 0.93 keV/nm at 0.5 MeV to 3.6 keV/nm at 10 MeV. This variation allows us to test which role the nuclear and the electronic collisions plays for the damage processes. The kinetic of the ion induced damage was determined by channeling RBS and the volume increase by profilometry. Single ion impacts create damage when electronic stopping dominates, while several impacts are necessary to achieve damage in the nuclear stopping regime. A detailed analysis allows us to deduce the damage cross-sections of the two processes. The electronic stopping power of damage creation appears above an electronic dE/dx threshold of 1.4±0.3 keV/nm

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

    Good resolution cross section and analyzing power (p vector, p') data for many states in 12C up to an excitation energy of 21 MeV and spanning a momentum transfer range of 0.3 to 2.1 fm-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

  20. Measurement and analysis of leakage neutron spectrum from a spherical pile of silicon with incident 14 MeV neutrons

    Absolute leakage neutron spectrum in the energy range between 0.1 and 15 MeV from a silicon spherical pile of 60-cm diameter was measured using an intense 14 MeV pulsed neutron source. OKTAVIAN, for the purpose of the benchmark validation of the nuclear data of silicon in JENDL-3.2, JENDL-3.3, ENDF/B-VI (release 2), ENDF/B-VI (release 5) and EFF-2.4. The neutron spectrum was compared with the calculated results using MCNP with different nuclear data. For estimating sensitivity of the individual cross section, the calculations were also performed using modified JENDL-3.2 based data libraries. It was found that the all nuclear data could predict the measured spectrum with the measurement fairly well. ENDF/B-VI (release 2) gave considerably large discrepancy over the whole energy region presumably caused by the inadequate inelastic scattering cross section values. The discrepancy found in the JENDL-3.2, JENDL-3.3 and EFF-2.4 between 5 and 10 MeV could be attributed to the too low values of the discrete inelastic scattering cross section values. The prediction with ENDF/B-VI (release 5) was almost satisfactory over whole energy region. (author)

  1. Depth-dependent nanoindentation hardness of reduced-activation ferritic steels after MeV Fe-ion irradiation

    Highlights: • We investigate nanoindentation hardness of reduced-activation ferritic steels after ion irradiation. • We model the depth-dependent bulk-equivalent hardness with considering indentation size effect. • We examine a film/substrate model to explain softer substrate effect. • Damage gradient effect is terminated by the appearance of softer substrate effect. • The critical depth of softer substrate effect depends on the amount of irradiation hardening. - Abstract: The irradiation hardening behavior of F82H reduced-activation ferritic steels after MeV Fe-ion beam irradiation experiments was investigated with a nanoindentation test. Two sets of ion-irradiation experiments were conducted at 270 °C with 10.5 MeV Fe3+ ions up to 5 dpa at a 1000 nm depth at TIARA facility and at 290 °C with 6.4 MeV Fe3+ ions up to 3 dpa at a 600 nm depth at DuET facility, respectively. The measured nanoindentation hardness was converted to the depth-dependent bulk-equivalent hardness based on a combination of the Nix–Gao model to explain the indentation size effect and the film/substrate model to explain the damage gradient effect in the ion-irradiated region and softer substrate effect of the non-irradiated region beyond the irradiated depth range

  2. Sustained performance of 8 MeV Microtron

    Energetic electrons and intense bremsstrahlung radiation from 8 MeV Microtron are being utilized in variety of collaborative research programs in radiation physics and allied sciences involving premier institutions of the country and sister universities of the region. The first of its kind electron accelerator in the country, set up at Mangalore University in collaboration with RRCAT Indore and BARC Mumbai, has been facilitating researchers since its inception with its inherent simplicity, ease of construction, low cost and excellent beam quality. A bird's eye view on the reliable aspects of the machine, efforts behind the continuous operation of the accelerator and important applications of the accelerator in physical and biological sciences are presented in this paper.

  3. The 50 MeV Beam Test Facility at LBL

    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 ampersand 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

  4. Focussed MeV ion beam implanted waveguides

    Von Bibra, M.L.; Roberts, A.; Nugent, K.; Jamieson, D.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    Single mode buried optical waveguides have been fabricated in fused silica by MeV proton implantation using a focussed hydrogen ion beam. The technique has the potential to direct write waveguide devices and produce multi-layered structures, without the need for intermediate steps such as mask fabrication or layered depositions. A micron resolution Confocal Raman Spectrometer has been used to map the distribution of atomic vacancies that forms the waveguiding region. The results are compared with theoretical calculations. Losses of 3 dB cm{sup -1} have been measured in unannealed samples, which decreases to less than 0.5 dB cm{sup -1} after annealing at 500 degrees Celsius. We describe methods for determining the refractive index distribution of single mode buried waveguides from their output intensity distributions via an inversion of the scalar wave equation. (authors). 5 figs.

  5. Proton-proton bremsstrahlung at 280 MeV

    A proton-proton bremsstrahlung experiment has been carried out at TRIUMF using a 280-MeV polarized proton beam impinging on a liquid-hydrogen target. All three outgoing particles were detected: the higher-energy proton in a magnetic spectrometer, the lower-energy proton with plastic scintillators, and the photon in lead-glass Cherenkov detectors. The experiment shows the first unambiguous evidence for off-shell effects in the free nucleon-nucleon interaction, in that the analyzing powers disagree strongly with the predictions of the soft-photon approximation (which incorporates only on-shell information) but are consistent with the results of calculations using the Bonn and Paris potentials

  6. Polarized triton elastic scattering at 17 MeV

    We present differential-cross-section and analyzing-power angular distributions for the elastic scattering of polarized tritons from 13 nuclei with 40 0 0 are the basis for an optical-model analysis in which parameters which fit both observables simultaneously are determined. It is observed that the analyzing-power data delimit the real potential well parameters much more precisely than do cross-section data alone. Although the spin-orbit potential is less well defined, the average spin-orbit well depth is V/sub so/=6.2 +- 1.5 MeV with geometry parameters similar to those for nucleons. The spin-orbit volume integrals are about a factor of 3 greater than predicted from simple folding models

  7. Reaction mechanism of light nuclei below 20 MeV

    The light nuclei are the elements in 1p shell. At the incident neutron energies below 20 MeV, the reaction mechanism could be classified as follows: 1. one particle emission, 2. sequential two particles emission, 3. the two cluster separation, when the residual are 8Be, 5He, 5Li, 4. three body break-up process, when the residual nuclei are 10Be, 6He. The Legendre expansion coefficients of the double differential cross section of outgoing particles in each type reaction mechanism are set up for the model calculating. The double differential cross section of secondary particle emission is calculated for light nuclei reaction and calculation formulation is also given. The problem on energy balance in light nuclear reaction is discussed

  8. Two charmoniumlike charged axial resonances near 3885 MeV

    Voloshin, M B

    2016-01-01

    It is argued that the charged $Z^+_c(3885)$ resonance, treated as a `molecular' state of charmed $D$ and $D^*$ mesons, is likely to consist of two peaks unequally coupled to the $D^{*+} \\bar D^0$ and $D^+ \\bar D^{*0}$ 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 of 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 $Z_c^\\pm(3885)$ to the states of charmonium plus a light meson.

  9. Multipole Stack for the 800 MeV PS Booster

    1975-01-01

    The 800 MeV PS Booster had seen first beam in its 4 superposed rings in 1972, routine operation began in 1973. In the strive for ever higher beam intensities, the need for additional multipole lenses became evident. After detailed studies, the manufacture of 8 stacks of multipoles was launched in 1974. Each stack consists of 4 superposed multipoles and each multipole has 4 concentric shells. From the innermost to the outermost shell, Type A contains octupole, skew-octupole, sextupole, skew-sextupole. Type B contains skew-octupole, skew-sextupole, vertical dipole, horizontal dipole. Completion of installation in 1976 opened the way to higher beam intensities. M. Battiaz is seen here with a multipole stack and its many electrical connections.

  10. The 5 MeV bump - a nuclear whodunit mystery

    Huber, Patrick

    2016-01-01

    We perform a combined analysis of recent NEOS and Daya Bay data on the reactor antineutrino spectrum. This analysis includes approximately 1.5 million antineutrino events, which is the largest neutrino event sample analyzed to date. We use a double ratio which cancels flux model dependence and related uncertainties as well as the effects of the detector response model. We find at 3-4 standard deviation significance level, that plutonium-239 and plutonium-241 are disfavored as the single source for the the so-called 5 MeV bump. This analysis method has general applicability and in particular with higher statistics data sets will be able to shed significant light on the issue of the bump. With some caveat this also should allow to improve the sensitivity for sterile neutrino searches in NEOS.

  11. Collective flow studies in central collisions between nuclei at several hundreds of MeV per nucleon

    The main purpose for studying collisions between heavy nuclei, in the 200-2000 MeV per nucleon energy range, is to determine the equation of state and the properties of dense and hot nuclear matter. The insensitiveness of the inclusive data to the equation of state has led experimental physicists to build large solid angle detectors capable of detecting simultaneously the tens of particles emitted in each event. Such measurements allow to estimate the impact parameter, the reaction plane on an event-by-event basis, and to calculate various global variables involving all particles emitted in each event. In this thesis, we study global variables which characterize the nuclear matter collective flow in a direction which is different from the direction of incident motion, for argon-nucleus collisions at 400 and 600 MeV by nucleon and for neon-nucleus collisions at 400 and 800 MeV by nucleon. The measurements have been performed with the DIOGENE detector installed at SATURNE. For the argon-beam experiments, two parallel plate avalanche counters have been used to locate the interaction point of each incoming ion with the target, which improves the reconstruction of the particle tracks in the DIOGENE central chamber. Double differential cross-sections, in the reaction plane and in the plane orthogonal to the reaction plane, are fitted with two-dimensional Gaussian distributions. Through this procedure, we get rid of geometrical acceptance effects. Several quantities, related to the collective flow (flow angle, aspect ratios, flow parameter), are thus extracted and corrected for the fluctuations of the estimated reaction plane. For argon-nucleus collisions at 400 MeV by nucleon, our results are in agreement with results obtained by other groups with different methods. For argon-nucleus collisions, the discrepancy between our experimental results and predictions of intranuclear cascade calculations is increasing with the mass asymmetry of the colliding system

  12. Collective flow studies in central collisions between nuclei at several hundreds of MeV per nucleon

    The main purpose for studying collisions between heavy nuclei, in the 200-2000 MeV per nucleon energy range, is to determine the equation of state and the properties of dense and hot nuclear matter. The insensitiveness of the inclusive data to the equation of state has led experimental physicists to build large solid angle detectors capable of detecting simultaneously the tens of particles emitted in each event. Such measurements allow to estimate the impact parameter, the reaction plane on an event-by-event basis, and to calculate various global variables involving all particles emitted in each event. In this thesis, we study global variables which characterize the nuclear matter collective flow in a direction which is different from the direction of incident motion, for argon-nucleus collisions at 400 and 600 MeV by nucleon and for neon-nucleus collisions at 400 and 800 MeV by nucleon. The measurements have been performed with the DIOGENE detector installed at SATURNE. For the argon-beam experiments, two parallel plate avalanche counters have been used to locate the interaction point of each incoming ion with the target, which improves the reconstruction of the particle tracks in the DIOGENE central chamber. Double differential cross sections, in the reaction plane and in the plane orthogonal to the reaction plane, are fitted with two-dimensional Gaussian distributions. Through this procedure, we get rid of geometrical acceptance effects. Several quantities, related to the collective flow (flow angle, aspect ratios, flow parameter), are thus extracted and corrected for the fluctuations of the estimated reaction plane. For the argon-nucleus collisions at 400 MeV by nucleon, our results are in agreement with results obtained by other groups with different methods. For argon-nucleus collisions, the discrepancy between our experimental results and predictions of intranuclear cascade calculations is increasing with the mass asymmetry of the colliding system

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

    Moiseev, A A; Buckley, J H; Caputo, R; Ferrara, E C; Hartmann, D H; Hays, E; McEnery, J E; Mitchell, J W; Ojha, R; Perkins, J S; Racusin, J L; Smith, A W; Thompson, D J

    2015-01-01

    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 pi- oneering, 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 her- itage of successful space missions including Fermi LAT, AGILE, AMS and PAMELA, and will utilize well-developed space...

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

    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.

  15. Little Boy neutron spectrum below 3 MeV

    The leakage neutron spectrum from the Little Boy replica has been measured from 12 keV to 3 MeV using a high-resolution 3He ionization chamber, and from 1 keV to 3 MeV using proton-recoil proportional counters. The 3He-spectrometer measurements were made at distances of 0.75 and 2.0 m from the active center and at angles of 00, 450, and 900 with respect to the axis of the assembly. Proton-recoil measurments were made at 900 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 3He spectrometer was calibrated at Los Alamos using monoenergetic 7Li(p,n)7Be 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

  16. Contribution to proton transport simulation from the MeV range to the keV range by the Monte-Carlo method

    This study settles on a contribution to the elaboration of slow protons transport simulation. Atomic inner shell ionization is studied in the Plane Wave Born Approximations and in the Binary Encounter Approximation. BRINKMAN-KRAMER's theory and DMITRIEV's theory are used to study charge exchange phenomena. Protons slowing down is studied with the BRICE's stopping power, with the VAVILOV and SYMON's energy straggling distributions and with the MOLIERE, KEIL and MEYER's angular deflexion distributions. Transport simulation is made with Monte Carlo Method; K electrons motion is also taken into account

  17. Inclusive π- production in heavy ion collisions below 100 A MeV

    Negative pion production in 41 A MeV 14N + C reaction was studied for Tπ ≥ 30 MeV and θlab ≤ 90 degrees. The cross sections fall exponentially with Tpi and the exponential slope factor in the spectrum at 95 degrees in the center of mass frame is determined to be 17.5 ± 2.0 MeV. The slope factor was found to be constant below beam energy. 100 A MeV which is anomalous compared to the monotonic decrease of the slope factor down to 100 A MeV. In this paper the preliminary result for 67 A MeV is given. The production mechanism of energetic pions far below the N-N threshold is discussed under several models

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

    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

  19. Neutron production from 200-500 MeV proton interaction with spacecraft materials

    We report on detailed energy spectra of neutron production >14 MeV from collisions of 200-500 MeV protons with combinations of aluminium, graphite and polyethylene. Comparisons of normalised neutron spectra are made with respect to incident proton energy, angle of neutron production and material. In general, carbon (graphite) or polyethylene (by itself or in combination with aluminium) reduce secondary neutron production >14 MeV relative to the production from interactions in aluminium. (authors)

  20. Assembly and installation of the 2 MeV FMIT accelerator

    The front end of the 35-MeV Fusion Materials Irradiation Test (FMIT) Facility accelerator is being assembled and installed at Los Alamos. The machine ultimately will produce a 500-kW continuous-duty beam at 5 MeV, although only the first 2 MeV will be installed this year. The 2-MeV system will include the most-powerful radio-frequency quadrupole (RFQ) in existence. The assembly and installation of the hardware are described, along with the unique problems arising from the large size and high power of the components involved

  1. (3He,t) reaction at 80MeV on 90Zr and 208Pb

    An experiment using the 80MeV 3He beam of the ISN cyclotron at Grenoble has been done on a target of 90Zr and another one of 208Bi. The 90Zr and 208Pb IAS angular distributions are fitted by DWBA calculations. For the previously reported Gamow Teller transition centered in 90Nb at 8.4MeV, two components are observed. The first one of M1 type is centered at 7.2MeV, the other one of unknown polarity at 9.7MeV

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

    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

  3. Neutron-induced fission cross sections of uraniums up to 40 MeV

    Maslov, V.M. [Radiation Physics and Chemistry Problems Inst., Minsk-Sosny (Belarus); Hasegawa, A.

    1998-11-01

    Statistical theory of nuclear reactions, well-proved below 20 MeV, is applied for {sup 235}U and {sup 238}U fission data analysis up to {approx}40 MeV. It is shown that measured data could be reproduced. Chance structure of measured fission cross section is provided, it`s validity is supported by description of data for competing (n,xn)-reactions. Role of fissility of target nucleus is addressed. It seems that gap in incident neutron energy interval of 20 MeV - 50 MeV, below which evaluation approaches are well-developed, and above which simplified statistical approaches are valid, could be covered. (author)

  4. Search for an elusive 4.4-MeV α emitter in uranium minerals

    A search for an unidentified 4.4-MeV α-emitter in Belgian Congo pitchblende and uranium raffinates is described, and a history of observations of 4.4-MeV activity over the last 55 years in radiogenic haloes, zinc ores, monazite, thorite, huttonite, ultrabasic and other abyssal rocks, osmiridium, uranium ores, and raffinates of uranium is given. No evidence of excess 4.4-MeV activity was shown in any of the chemically separated fractions investigated. Upper limits for 4.4-MeV α activity in each of four studied samples are given

  5. Enhanced photoelectrochemical properties of 100 MeV Si8+ ion irradiated barium titanate thin films

    Highlights: ► Effect of 100 MeV Si8+ ion irradiation on photoelectrochemical (PEC) properties of BaTiO3 thin films was studied. ► Films were deposited on Indium doped Tin Oxide (ITO) coated glass by sol–gel spin coating technique. ► Optimal irradiation fluence for best PEC response was 5 × 1011 ion cm−2. ► Maximum photocurrent density was observed to be 0.7 mA cm−2 at 0.4 V/SCE. ► Enhanced photo-conversion efficiency was due to maximum negative flatband potential, donor density and lowest resistivity. -- Abstract: Effects of high electronic energy deposition on the structure, surface topography, optical property and photoelectrochemical behavior of barium titanate (BaTiO3) thin films were investigated by irradiating films with 100 MeV Si8+ ions at different ion fluences in the range of 1 × 1011–2 × 1013 ions cm−2. BaTiO3 thin films were deposited on indium tin oxide coated glass substrate by sol gel spin coating method. Irradiation induced modifications in the films were analyzed using the results from XRD, SEM, cross sectional SEM, AFM and UV–Vis spectrometry. Maximum photocurrent density of 0.7 mA cm−2 at 0.4 V/SCE and applied bias hydrogen conversion efficiency (ABPE) of 0.73% was observed for BaTiO3 film irradiated at 5 × 1011 ions cm−2, which can be attributed to maximum negative value of the flatband potential and donor density and lowest resistivity

  6. High resolution (γ, n) experiments in light nuclei at Eγ ≅ 60 MeV

    The experiments was undertaken to establish the real photon reaction mechanism on light nuclei in the intermediate photon-energy region, Eγ ≅ 60 MeV. The shortage of high quality (γ, n) data was the main motivation for starting a systematic investigation of this reaction channel. In this work, 12C and 16O were examined. In the future, both heavier (40Ca) and lighter (4He) targets will be investigated. Two neutron detector arrays were built and tested. A state-of-the-art neutron spectrometer was constructed by combining these arrays with a high resolution (≅ 300 keV) photon tagger. The intrinsic time resolution of this spectrometer (≅ 800 ps) allowed an excellent neutron energy resolution to be achieved (≅ 1 MeV) with fairly short flight paths (≅ 6 m), thereby optimizing the geometrical efficiency (≅ 10 msr) of the apparatus. The excellent energy resolution of the spectrometer allowed individual states (or cluster of states) to be resolved. This resolution approaches that available for the (γ, p) reaction. For 12C and 16O the same states seen in the (γ, p) reaction were observed over an angular range from 30-115 degrees. The most important result, concerning the obtained absolute differential cross sections, is the striking similarity between the (γ, p) and (γ, n) reaction channels. This applies to both target nuclei for all populated states, independent of character (1h or 2h1p). A much detailed comparison is thus possible with these new data, providing greater constraints on the theoretical models. Further, access to more and better data will hopefully attract greater theoretical interest. The experiment was a collaboration between the Photonuclear research group at Lund University in Sweden and the Nuclear structure group from the University of Glasgow. The data were collected at MAX-lab in Lund, Sweden, during two run periods in November 1990 and February 1992. 96 refs, 105 figs, 28 tabs

  7. Cross Sections for High-Energy Gamma Transitions from MeV Neutron Capture in 206Pb

    Gamma-ray spectra from neutron capture in Pb (radiogenic lead) in the energy range 1.5 to 8.5 MeV were recorded using time-of-flight techniques. The spectrometer was a Nal (Tl) crystal, 20.8 cm long and 22.6 cm in diameter. The spectra are dominated by gamma transitions to levels with large single-particle strength, in agreement with predictions of semi-direct capture theories. The theories predict enhancements of the direct capture cross section by a factor of 10 - 15 in the region of the giant dipole resonance. The observed enhancement is about 50

  8. Program DDCS for nucleon and composite particle DDX of nucleon induced reactions up to tens of MeV

    DDCS is a program for calculating the neutron or proton induced reactions of medium-heavy nuclei in the incident energy range up to 50 MeV including 5 emission processes. This program is written in FORTAN-77 on microscopic computer 486. DDCS is constructed within the framework of optical model, generalized master equation of the exciton model, and the evaporation model. The effect of recoil nucleus is considered in this program. DDCS has been used to calculate reactions of n + 56Fe, n + 93Nb, P + 120Sn, P + 197Au, and P + 209Bi. Pretty good results in agreement with the experimental data were obtained

  9. Heavy ion reaction studies of NbAu at E/A = 50, 75 and 100 MeV

    We report on measurements of the system Nb+Au at incident energies of E/A = 50, 75 and 100 MeV made with a large solid angle, large dynamic range gas-scintillator array. We observe that in these reactions fission is the result of peripheral collisions. Somewhat less peripheral reactions result in heavy residues which do not undergo fission. More central reactions result in high multiplicities of light particles and intermediate mass fragments. Correlations between fragments, energetic light charged particles, and forward moving projectile-like fragments are presented to support these observations. (orig.)

  10. Influence of 2 MeV electrons irradiation on gallium phosphide light-emitting diodes reverse currents

    Results of reverse electrophysical characteristics study of red and green LED's, initial and irradiated with 2 MeV electrons were given. It was found that reverse current was predominantly caused by carriers tunneling at Urev <- 9 V, and by the avalanche multiplication at Urev >- 13 V, in the range U = 9-13 V both mechanisms are available. Current increase at high voltage areas (Urev > 19 V) is limited by the base resistance of diode. In the case of significant reverse currents (I > 1 mA) irradiation of diodes leads to the shift of reverse current-voltage characteristics into the high voltages direction

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

    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

  12. Production of medium-weight isotopes by fragmentation in 750 A MeV 238U on 208Pb collisions

    Projectile fragmentation of 238U in a lead target was investigated at a bombarding energy of 750 A MeV. Isotopic production cross sections of about 250 different projectile fragments in the element range Z=30-53 were measured with the fragment separator (FRS). The magnetic selection and the kinematical analysis of the measured isotopes allowed to disentangle fission and fragmentation residues. The mass loss of these residues indicates a violent collision where a large amount of energy is dissipated. The position of the fragmentation corridor defined by the measured residues was used to determine an effective proton-evaporation barrier. (orig.)

  13. Spectroscopic quadrupole moment of the 2+ state at 4.439 MeV in 12C

    The long standing predictions of α-cluster states in 12C plays an important role to account for the observed abundance of carbon in the Universe. The α-cluster configurations based on 02+ state (Hoyle state) at 7.65 MeV has considerable mixing with the 0+ ground state and decays to it via the 21+ excited state. Theoretically, the predictions of various model calculations such as isomorphic shell model, rotational models, α-particle model etc., are inconsistent with each other and suggest the ground state of 12C associate with deformation ranging from spherical to strong oblate

  14. Investigation of incomplete fusion dynamics from the measurement of angular distributions at E ≈ 88 MeV

    The present work has been carried out to provide some definite conclusions regarding ICF reaction dynamics below 10 MeV/nucleon energies. We have measured the angular distributions of evaporated residues produced in 12C + 175Lu system at ≈ 88 MeV energy. Moreover, this work is aimed to provide the new experimental data on angular distributions, which is not available in the literature to the best of our knowledge. This is a complementary experiment to support and strengthen the findings of Excitation Functions and Recoil Range Distribution measurements

  15. Investigation of nα-reactions on medium mass nuclei at En 4.5-6.75 MeV

    The 39K(nα)36Cl, 40Ca(nα)37Ar and 64Zn (nα)61Ni reactions are studied within the energy values range of 4.5-6.75 MeV. The energy spectra and reaction products angular distributions are obtained. The complete and partial cross sections of the transitions into the excited states of the daughter nuclei as well as the differential cross sections are determined. The analysis of the obtained data is carried out within the frames of the optical model alongside with the data from other works

  16. The reaction 7Li(e,3H)4He,e' between 6 and 15 MeV

    Tritons resulting from the electrodisintegration of 7Li have been measured at 90 deg for an incident electron energy of 23.8 MeV over an energy range which ensured that only tritons emitted in the two-body channel were detected. The electrodisintegration cross sections were converted to equivalent photodisintegration data and compared to earlier results. Large discrepancies are observed. It is found that the (γ,3H) channel contributes appreciably to the electric dipole sum rule for 7Li. (author)

  17. Beam-dump/diagnostics box for a 10-kA 50-MeV, 50-ns electron beam

    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 600 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

  18. Cooperative long range protein-protein dynamics in Purple Membrane

    Rheinstadter, Maikel; Schmalzl, Karin; Wood, Kathleen; Strauch, Dieter

    2008-01-01

    We present experimental evidence for a long-range protein-protein interaction in purple membrane (PM). The interprotein dynamics were quantified by measuring the spectrum of the acoustic phonons in the 2D bacteriorhodopsin (BR) protein lattice using inelastic neutron scattering. Phonon energies of about 1 meV were determined. The data are compared to an analytical model, and the effective spring constant for the interaction between neighboring protein trimers are determined to be k=53 N/m. Ad...

  19. Telemetry Ranging: Concepts

    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.

  20. Minnesota Pheasant Range

    Minnesota Department of Natural Resources — This dataset delineates the spatial range of wild pheasant populations in Minnesota as of 2002 by dividing the MN state boundary into 2 units: pheasant range and...

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

    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

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

    Kumar, M. Vinay, E-mail: Vkm288@gmail.com; Krishnaveni, S. [Department of studies in Physics, University of Mysore, Manasagangotri, Mysore 570006 (India); Yashoda, T. [Deparment of Physics, AVK College for women, Hassan-573201 (India); Dinesh, C. M. [Department of Physics, Govt. First grade college for women, Chintamani-563125 (India); Krishnakumar, K. S. [Department of Physics, APS College of Engineering (India); Jayashree, B. [Department of Physics, Maharanis Science College for Women, Bangalore-560001 (India); Ramani [Department of Physics, Bangalore University, Jnanabharathi, Bangalore-560056 (India)

    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. Gain ranging amplifier

    A gain ranging amplifier system is provided for use in the acquisition of data. Voltage offset compensation is utilized to correct errors in the gain ranging amplifier system caused by thermal drift and temperature dependent voltage offsets, both of which are associated with amplifiers in the gain ranging amplifier system

  4. Monitoring of a 14 MeV neutron source

    Accelerator-driven systems (ADS) may allow the transmutation of the most radio-toxic nuclear waste. They consist of the coupling of an intense high-energy proton beam, hitting a high atomic number target, and a sub-critical reactor core. For safety reasons, an on-line accurate and robust core reactivity monitoring is mandatory. The beam current delivered by the accelerator and the power level, or neutron flux, of the reactor core are strongly correlated through a proportionality relationship which has to be investigated, since, among different techniques, it could give access to any reactivity change. To demonstrate the feasibility of such an on-line reactivity monitoring, an experimental program is planned at the YALINA facility, in Bielorussia, in the framework of the EUROTRANS Integrated Project (6. FP). At this sub-critical installation, the incident 14 MeV neutron flux is produced by a deuteron beam impinging on a 3H target. Due to the consumption of the 3H target, the deuteron beam current will not remain proportional to the neutron production-rate over time. Therefore, in order to monitor the neutron production rate, we developed a new detector device. It is composed of a thin CH-2 foil, followed by three Si detectors. This telescope will be installed a few meters downstream the 3H target, at 0 deg.. The detection method is based on the conversion of neutrons into recoiling protons, which are then detected by the three Si. Their thicknesses and thresholds have been chosen so that the most energetic protons, associated with the 14 MeV neutrons, are stopped in the last stage of the telescope. Requiring triple coincidences in the telescope enable then to select events originating only from neutrons produced in the d+3H reactions. Doing so, the correlation between a change of the source intensity and the flux will be kept and the proportionality constant can be investigated and determined (via a calibration) and therefore used to detect any reactivity change of

  5. Ultrafast laser driven micro-lens to focus and energy select MeV protons

    A technique for simultaneous focusing and energy selection of high-current, MeV proton beams using radial, transient electric fields (107-1010 V/m) triggered on the inner wall of a hollow micro-cylinder by an intense, sub-picosecond laser-pulse is presented. Due to the transient nature of the radial focusing field, the proposed method allows selection of a desired range out of the spectrum of the poly-energetic proton beam. This technique addresses current drawbacks of laser-accelerated proton beams, i.e. their broad spectrum and divergence at the source. This thesis presents both experimental and computational studies that led to the understanding of the physical processes driving the micro-lens. After an one side irradiation of a hollow metallic cylinder a radial electric field develops inside the cylinder. Hot electrons generated by the interaction between laser pulse and cylinder wall spread inside the cylinder generating a plasma at the wall. This plasma expands into vacuum and sustains an electric field that acts as a collecting lens on a proton beam propagating axially through the cylinder. Both focusing and the reduction of the intrinsic beam divergence from 20 deg to.3 deg for a narrow spectral range was demonstrated. By sub-aperturing the beam a narrow spectral range (δε/ε < 3%) was selected from the poly-energetic beam. The micro-lens properties are tunable allowing for optimization towards applications. Optical probing techniques and proton imaging were employed to study the spacial and temporal evolution of the field and revealed a complex physical scenario of the rise and decay of the radial electric field. Each aspect studied experimentally is interpreted using 2D PIC and ray tracing simulations. A very good agreement between the experimental and computational data is found. The PIC simulations are used to upscale the demonstrated micro-lens capabilities to the focusing of a 270 MeV proton beam, an energy relevant for medical applications such as

  6. Ultrafast laser driven micro-lens to focus and energy select MeV protons

    Toncian, Toma

    2008-05-15

    A technique for simultaneous focusing and energy selection of high-current, MeV proton beams using radial, transient electric fields (10{sup 7}-10{sup 10} V/m) triggered on the inner wall of a hollow micro-cylinder by an intense, sub-picosecond laser-pulse is presented. Due to the transient nature of the radial focusing field, the proposed method allows selection of a desired range out of the spectrum of the poly-energetic proton beam. This technique addresses current drawbacks of laser-accelerated proton beams, i.e. their broad spectrum and divergence at the source. This thesis presents both experimental and computational studies that led to the understanding of the physical processes driving the micro-lens. After an one side irradiation of a hollow metallic cylinder a radial electric field develops inside the cylinder. Hot electrons generated by the interaction between laser pulse and cylinder wall spread inside the cylinder generating a plasma at the wall. This plasma expands into vacuum and sustains an electric field that acts as a collecting lens on a proton beam propagating axially through the cylinder. Both focusing and the reduction of the intrinsic beam divergence from 20 deg to.3 deg for a narrow spectral range was demonstrated. By sub-aperturing the beam a narrow spectral range ({delta}{epsilon}/{epsilon} < 3%) was selected from the poly-energetic beam. The micro-lens properties are tunable allowing for optimization towards applications. Optical probing techniques and proton imaging were employed to study the spacial and temporal evolution of the field and revealed a complex physical scenario of the rise and decay of the radial electric field. Each aspect studied experimentally is interpreted using 2D PIC and ray tracing simulations. A very good agreement between the experimental and computational data is found. The PIC simulations are used to upscale the demonstrated micro-lens capabilities to the focusing of a 270 MeV proton beam, an energy relevant

  7. Telemetry Ranging: Signal Processing

    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.

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

    A new hybrid surrogate ratio approach has been employed to determine neutron-induced fission cross sections of 233Pa in the energy range of 11.5 to 16.5 MeV for the first time. The fission probability of 234Pa and 236U compound nuclei produced in 232Th(6Li, α)234Pa and 232Th(6Li, d)236U transfer reaction channels has been measured at Elab=38.0 MeV in the excitation energy range of 17.0 to 22.0 MeV within the framework of the absolute surrogate method. The 233Pa(n,f) cross sections are then deduced from the measured fission decay probability ratios of 234Pa and 236U compound nuclei using the surrogate ratio method. The 233Pa(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

  9. Telemetry-Based Ranging

    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.

  10. Supervisory control system for 10 MeV linac

    A 10 MeV Linac is being tested at Raja Ramanna Centre for Advanced Technology. The Linac system consists of subsystems like RF system, magnet power supplies, vacuum pumps and gauges, radiation monitoring systems, interlocks and personnel safety system and the support systems required for the operation of Linac. A supervisory control system for Linac and associated subsystems is developed at Raja Ramanna Centre for Advanced Technology. The control system features monitoring and controls of diversified subsystems, timing trigger system, synthesizer, oscilloscopes, machine and personnel safety interlocks. The control system hardware is VME bus based controller referred to as the Equipment controller (EC). All the subsystems are interfaced to the EC with isolation in each interface signal. Interlocks are supervised directly in hardware. Personnel safety is ensured by the 'Area Search' interlock. The software layer of the control system consists of a server and client based Supervisory Control And Data Acquisition (SCADA) system implemented in LabView. Software system also includes GUI at operator console and dedicated softwares developed to control various instruments connected on Ethernet. The server interacts with the EC over RS232 link. A Web site is also developed to locally display the historical data of beam current, beam energy and facilitates the retrieval of the various parameter values logged in the data base. The paper describes the architecture of control system, the hardware and software developments, features and operational experiences. (author)

  11. Multipurpose 5-MeV linear induction accelerator

    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

  12. Calculation of 14 MeV neutron transmission

    The possibility of using the 28 group constant system (28-GCS) for calculating the transport of neutrons with initial energy of 14 MeV in thermonuclear reactor blankets is studied. A blanket project suggested by the Oak Ridge National Laboratory is used as a test version to estimate applicability of the 28-GCS. Niobium is used in a blanket as a structural material. A mixture of lithium nuclides is used for tritium production. The results of blanket test calculation and the calculational results obtained using the 28-GCS from the UKNDL library are compared. The numerical 28-group calculation of blonket is carried out by means of the ROZ-6 and ROZ-9 codes but not by the Monte-Carlo method as compared with the test calculation. Time of the blanket calculation on the BESM-6 computer by means of the ROZ-9 code in 2P5 approximation using the 28-GCS amounts to 10 min. It is noted that to create effective codes for the numerical blanket calculation different calculational grids are necessary for different energy grups. The calculations carried out have shown the possibility of using the 28-group library of cross sections for the numerical solution of the neutron transport equation in estimating analysis of blankets

  13. Multipurpose 5-MeV linear induction accelerator

    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.

  14. Two-color infrared FEL facility employing a 250-MeV Linac injector for SAGA synchrotron light source

    A two-color infrared free electron laser (FEL) facility is proposed, for which a 250-MeV linac type injector for the Saga synchrotron light source (SLS) is employed in FEL mode. The linac has two operation modes; short macropulse mode of 1 μa at 250 MeV for injection to the 1.4 GeV storage ring and long macropulse mode of 13 μs at 40 MeV for two-color infrared FEL facility, where simultaneous infrared (IR) and far-infrared (FIR) FELs are supplied for application researches by using two undulators for IR and FIR ranges like the FEL two-color FEL facility. The macropulse beam consists of a train of several ps, 0.6 nC micropulses (peak current 100A) repeating at 22.3125 or 89.25 MHz. The two-color FEL facility can supply high-power density photon beams of 10-GW/cm2 level covering an attractive wavelength range from 3.1 μm(0.4 eV) to 248 μm(0.005 eV) for scientific researches, bio-medical and industrial applications. The construction of the Saga SLS has been conducted by the Saga Prefectural Government as a six-year project started in 1998. The project is promoted by the Science and Technology Agency and the Saga Prefectural Government. The Saga SLS will be operated in 2004 to promote material science, bio-medical and industrial applications in Kyushu area. (author)

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

    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.

  16. Leptonic origin of the 100 MeV gamma-ray emission from the Galactic Centre

    Malyshev, D; Neronov, A; Walter, R

    2015-01-01

    The Galactic Centre is a bright gamma-ray source with the GeV-TeV band spectrum composed of two distinct components in the 1-10 GeV and 1-10 TeV energy ranges. The nature of these two components is not clearly understood. We investigate the gamma-ray properties of the GC in order to clarify the origin of the observed emission. We report imaging, spectral and timing analysis of the data of 74 months of observations of the Galactic Centre by FERMI/LAT gamma-ray telescope complemented by the sub-MeV data from ~10 years of INTEGRAL/PICsIT observations. We find that in the GeV band the Galactic Centre is spatially consistent with a point source. The 3 sigma upper limit on its radius is 0.13 degree. The spectrum of the source in the 100 MeV energy range does not have a characteristic turnover which would point to the pion decay origin of the signal. Instead, the source spectrum is consistent with a model of inverse Compton scattering by high-energy electrons. In such a model, the GeV bump in the spectrum originates...

  17. X-ray generation by MeV electrons in silicon: temperature, tilt, and thickness dependence

    When relativistic electrons strike a single crystal target, sharp peaks are observed in the x-ray spectrum generated. One type of radiation, called coherent bremsstrahlung, results from coherent electron scattering by atoms arranged on the crystal lattice. The other type of radiation is channeling radiation. The electrons channeling near major crystal axes enter quantized orbits and emit x-ray photons as a consequence of transitions between orbits. Observations of channeling and coherent bremsstrahlung spectra using 2 to 3 MeV electrons incident on targets 1 and 3 μm thick are described. Large changes in channeling x-ray energies and intensities are observed over a narrow range of temperature from room temperature to 20000C. There are no such large changes in the coherent bremsstrahlung spectra under the same conditions. Intensity measurements over a range of thicknesses for both types of radiation are reported. Finally, changes in the energy of the highest energy channeling peak are found as the channeling axis is tilted away from the electron beam

  18. High-sensitivity measurements of the excitation function for Bhabha scattering at MeV energies

    Using a monochromatic e+ beam scattered on a Be foil and a high-resolution detector device, the excitation function for elastic e+e- scattering was measured with a statistical accuracy of 0.25% in 1.4 keV steps in the c.m.-energy range between 770 keV and 840 keV (1.79 - 1.86 MeV/c2) at c.m. scattering angles between 800 and 1000 (FWHM). Within the experimental sensitivity of 0.5 b.eV/sr (c.m.) for the energy-integrated differential cross section no resonances were observed (97% CL). From this limit we infer that a hypothetical spinless resonant state should have a width of less than 1.9 meV corresponding to a lifetime limit of 3.5x10-13 s. This limit establishes the most stringent bound for new particles in this mass range derived from Bhabha scattering and is independent of assumptions about the internal structure of the hypothetical particles. Less sensitivite limits were, in addition, derived around 520 keV c.m. energy (≅ 1.54 MeV/c2) from an investigation with a thorium and a mylar foil as scatterers. (orig.)

  19. Nuclear halo of a 177\\,MeV proton beam in water

    Gottschalk, Bernard; Daartz, Juliane; Wagner, Miles S

    2014-01-01

    The dose distribution of a pencil beam in a water tank consists of a core, a halo and an aura. The core consists of primary protons which suffer multiple Coulomb scattering (MCS) and slow down by multiple collisions with atomic electrons (Bethe-Bloch theory). The halo consists of charged secondaries, many of them protons, from elastic interactions with H, elastic and inelastic interactions with O, and nonelastic interactions with O. We show that the halo radius is roughly one third of the beam range. The aura consists of neutral secondaries (neutrons and gamma rays) and the charged particles they set in motion. We have measured the core/halo at 177 MeV using a test beam offset in a water tank. The beam monitor was a plane parallel ionization chamber (IC) and the field IC a dose calibrated Exradin T1. Our dose measurements are absolute. We took depth-dose scans at ten displacements from the beam axis ranging from 0 to 10 cm. The dose spans five orders of magnitude, and the transition from halo to aura is obvio...

  20. Measurement of charge symmetry breaking in np elastic scattering at 350 MeV

    TRIUMF experiment 369, a measurement of charge symmetry breaking in np elastic scattering at 350 MeV, has completed data taking. Scattering asymmetries were measured with a polarized (unpolarized) neutron beam incident on an unpolarized (polarized) frozen spin target. Coincident scattered neutrons and recoil protons were detected by a mirror symmetric detection system in the center-of-mass angle range from 50 deg - 90 deg. A preliminary result for the difference of the zero-crossing angles, where analyzing powers cross zero, is Δθcm = 0.445 deg ± 0.054 deg (stat.) ± 0.051 deg (syst.) based on fits over the angle range 53.4 deg ≤ θcm ≤ 86.9 deg. The difference of the analyzing powers ΔA ≡ An - Ap, where the subscripts denote polarized nucleons, was deduced with dA/dθcm = (-1.35 ± 0.05) x 10-2deg-1 to be [60 ± 7(stat.) ± 7(syst.) ± 2(syst.)] x 10-4. (author). 11 refs., 6 figs