WorldWideScience

Sample records for k-electron capture probabilities

  1. K-electron capture probability in 171Lu

    International Nuclear Information System (INIS)

    Mishra, N.R.; Vara Prasad, N.V.S.; Chandrasekhara Rao, M.V.S.; Satyanarayana, G.; Sastry, D.L.; Chintalapudi, S.N.

    1999-01-01

    The K-electron capture probability in the decay of 171 Lu to the 835.06 keV level of the daughter nucleus 171 Yb is measured to be 0.822 ± 0.027 involving two transitions, in agreement with the theoretical value 0.833. The experimental value is seen to be consistent with the mass prediction of the relationship due to Wapstra and Bos. (author)

  2. Measurement of K-electron capture probability in the decay of 87Y

    International Nuclear Information System (INIS)

    Prasad, N.V.S.V.; Murty, G.S.K.; Rao, M.V.S.C.; Sastry, D.L.

    1993-01-01

    The K-electron capture probability for the 1/2 - to 3/2 - transition in the decay of 87 Y to the 873.0 keV level in the daughter 87 Sr was measured for the first time using an x-γ summing method. The experimental P K value was found to be 0.911 ± 0.047, in agreement with the theoretical value of 0.878. (author)

  3. Relative K-electron capture probabilities in the decay of 99Rh

    International Nuclear Information System (INIS)

    Mishra, N.R.; Chandrasekhar Rao, M.V.S.; Satyanarayana, G.; Sastry, D.L.; Chintalapudi, S.N.

    2000-01-01

    The relative K-electron capture probabilities (P K ) to the 1383.23, 896.98, 618.09, 442.78 and 322.43 keV levels in 99 Ru in the decay of 99 Rh are measured employing the X-γ internal sum-coincidence technique. The measured values P K 1383.23=0.851±0.066, P K 896.98=0.834±0.061, P K 618.09=0.870±0.01, P K 442.78=0.882±0.035 and P K 322.43=0.852±0.061 are found to be in good agreement with the theoretical values. The dependence of P K on EC transition energy is discussed. (author)

  4. Measurement of K-electron capture probability in the decay of [sup 87]Y

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, N.V.S.V.; Murty, G.S.K.; Rao, M.V.S.C.; Sastry, D.L. (Andhra Univ., Visakhapatnam (India). Labs. for Nuclear Research); Chintalapudi, S.N. (Inter University Consortium for DAE Facilities, Calcutta (India))

    1993-04-01

    The K-electron capture probability for the 1/2[sup -] to 3/2[sup -]transition in the decay of [sup 87]Y to the 873.0 keV level in the daughter [sup 87]Sr was measured for the first time using an x-[gamma] summing method. The experimental P[sub K] value was found to be 0.911 [+-] 0.047, in agreement with the theoretical value of 0.878. (author).

  5. Measurement on K-electron capture probability in the decay of 97Ru

    International Nuclear Information System (INIS)

    Kalayani, V.D.M.L.; Vara Prasad, N.V.S.; Chandrasekhar Rao, M.V.S.; Satyanarayana, G.; Sastry, D.L.; Chintalapudi, S.N.

    1999-01-01

    The K-electron capture probabilities of two strong allowed transitions 5/2 + →5/2 + and 5/2 + →7/2 + were measured in the decay of 97 Ru employing the X-γ internal summing technique. The two P K experimental values were found to be 0.884±0.046 and 0.886±0.018 in agreement with the theoretical values 0.878 and 0.878, respectively. The theoretical values are seen to be insensitive for Q EC values above 200 keV

  6. Measurement on K-electron capture probabilities in the decay of [sup 183]Re and [sup 168]Tm

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, N.V.S.V.; Rao, M.V.S.C.; Reddy, S.B.; Satyanarayana, G.; Sastry, D.L. (Andhra Univ., Visakhapatnam (India). Swami Jnanananda Labs. for Nuclear Research); Murty, G.S.K. (UNDNJ, Newark, NJ (United States). Dept. of Radiology); Chintalapudi, S.N. (Inter University Consortium for DAE Facilities, Calcutta (India))

    1994-03-01

    The K-electron capture probabilities for the 5/2[sup +] to 3/2[sup -]transition in the electron capture decay of [sup 183]Re to the 208.805 keV level in the daughter [sup 183]W and for the 3[sup (+)] to 3[sup -]and 3[sup (+)] to 4[sup -] transitions in the electron capture decay of [sup 168]Tm to the 1541.4 keV and 1093.0 keV levels, respectively, in the daughter [sup 168]Er were measured for the first time using an x-[gamma] summing method. The experimental P[sub K] values are reported in this paper, together with those due to theory, and discussed. (Author).

  7. Measurement on K-electron capture probability in the decay of {sup 97}Ru

    Energy Technology Data Exchange (ETDEWEB)

    Kalayani, V.D.M.L.; Vara Prasad, N.V.S.; Chandrasekhar Rao, M.V.S.; Satyanarayana, G.; Sastry, D.L. [Swami Jnanananda Laboratories for Nuclear Research, Andhra University, Visakhapatnam (India); Chintalapudi, S.N. [Inter University Consortium for DEA Facililities, Calcutta (India)

    1999-08-01

    The K-electron capture probabilities of two strong allowed transitions 5/2{sup +}{yields}5/2{sup +} and 5/2{sup +}{yields}7/2{sup +} were measured in the decay of {sup 97}Ru employing the X-{gamma} internal summing technique. The two P{sub K} experimental values were found to be 0.884{+-}0.046 and 0.886{+-}0.018 in agreement with the theoretical values 0.878 and 0.878, respectively. The theoretical values are seen to be insensitive for Q{sub EC} values above 200 keV.

  8. Experimental study of K-electron capture probability in the decay of {sup 111}In

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, N.R.; Kalyani, V.D.M.L.; Maldhusudhana Rao, P.V.; Vara Prasad, N.V.; Chandrasekhar Rao, M.V.S.; Satyanarayana, G.; Sastry, D.L. [Visakhapatnam, Andhra Univ. (India). Swami Jnanananda Lab. for Nuclear Research; Chintalapudi, S.N. [Calcutt, Inter-Univ. Consortium for DAEW Facilities (India)

    1998-03-01

    The K-electron capture probability in the decay of {sup 111}In to the 416.64 keV level of the daughter nucleus {sup 111}Cd was measured to be 0.853 {+-}0.037 in agreement with the theoretical value 0.865. The experimental value is seen to be consistent with the mass prediction of the relationship due to Wapstra and Bos.

  9. Electron capture probabilities in sup 105 Ag

    Energy Technology Data Exchange (ETDEWEB)

    Chandrasekhar Rao, M.V.S.; Sree Krishna Murty, G.; Radha Krishna, K.; Bhuloka Reddy, S.; Satyanarayana, G.; Raghavaiah, C.V.; Sastry, D.L. (Andhra Univ., Visakhapatnam (India). Labs. for Nuclear Research); Chintalapudi, S.N. (Bhabha Atomic Research Centre, Calcutta (India). Variable Energy Cyclotron Centre)

    1990-01-01

    The K-electron capture probabilities for the 1/2{sup -}yields3/2{sup -} and 1/2{sup -}yields1/2{sup +} transitions in the decay of {sup 105}Ag were measured for the first time using the sum coincidence method. The experimental P{sub K} values were estimated to be 0.824{plus minus}0.042 and 0.851{plus minus}0.046 for the allowed and first-forbidden beta transitions, respectively in agreement with the theory. The P{sub L} experimental values to these two levels were also computed using the experimental P{sub L}/P{sub K} values reported by earlier authors. These results are also found to be consistent with the theoretical P{sub L} values. (orig.).

  10. Double K-shell ionization in electron capture decay

    International Nuclear Information System (INIS)

    Intemann, R.L.

    1985-01-01

    Using a semirelativistic theory previously developed by the author, we have computed the total probability per K-capture event for the ionization of the remaining K electron for a dozen nuclides of interest. Based on hydrogenic wave functions and accurate to relative order (Zα) 2 , the theory takes into account the correlation between the two initial K electrons and permits adjustments for screening. Numerical results exhibiting the effects of screening are presented. A comprehensive comparison of the predictions of this theory, as well as those of other theoretical models, with recent experimental data is also given

  11. New approach to K-electron-capture probabilities to the 437 and 384 keV levels in the decay of /sup 133/Ba

    Energy Technology Data Exchange (ETDEWEB)

    Singh, K; Sahota, H S [Punjabi Univ., Patiala (India). Dept. of Physics

    1983-12-01

    The K-electron-capture probabilities to the 437 and 384 keV levels in the decay of /sup 133/Ba have been determined from a measurement of gamma-ray intensities in conjunction with an analysis of the K x-ray-gamma-ray sum peaks. The results are independent of fluorescence yield and detector efficiency.

  12. Κ-electron capture probability in 167Tm

    International Nuclear Information System (INIS)

    Sree Krishna Murty, G.; Chandrasekhar Rao, M.V.S.; Radha Krishna, K.; Bhuloka Reddy, S.; Satyanarayana, G.; Ramana Rao, P.V.; Sastry, D.L.

    1990-01-01

    The Κ-electron capture probability in the decay of 167 Tm for the first-forbidden transition 1/2 + →3/2 - was measured using the sum-coincidence method and employing a hyper-pure Ge system. The P Κ value is found to be 0.835±0.029, in agreement with the theoretical value of 0.829. (author)

  13. K-capture probabilities in the decay of /sup 133/Ba

    Energy Technology Data Exchange (ETDEWEB)

    Singh, K; Sahota, H S

    1983-07-01

    The K-capture probabilities in the decay of /sup 133/Ba to 437, 383, 161 and 81 keV levels have been determined from the analysis of the K X-ray-gamma ray sumpeaks observed with an intrinsic Ge detector. The measurements on 161 and 81 keV levels are reported for the first time in literature.

  14. Kappa. -electron capture probability in sup 167 Tm

    Energy Technology Data Exchange (ETDEWEB)

    Sree Krishna Murty, G.; Chandrasekhar Rao, M.V.S.; Radha Krishna, K.; Bhuloka Reddy, S.; Satyanarayana, G.; Ramana Rao, P.V.; Sastry, D.L. (Andhra Univ., Visakhapatnam (India). Labs. for Nuclear Research); Chintalapudi, S.N. (Variable Energy Cyclotron Centre, Calcutta (India))

    1990-07-01

    The {Kappa}-electron capture probability in the decay of {sup 167}Tm for the first-forbidden transition 1/2{sup +}{yields}3/2{sup -} was measured using the sum-coincidence method and employing a hyper-pure Ge system. The P{sub {Kappa}} value is found to be 0.835{plus minus}0.029, in agreement with the theoretical value of 0.829. (author).

  15. Determination of Psub(K) values to the 172, 103 and 97 keV levels and the fluorescence yield. omega. sub(K) of Eu after electron capture by /sup 153/Gd

    Energy Technology Data Exchange (ETDEWEB)

    Singh, K; Grewal, B S; Sahota, H S [Punjabi Univ., Patiala (India). Dept. of Physics

    1985-03-01

    From an analysis of K x-ray-..gamma..-ray sum peaks observed with an intrinsic Ge detector the K-capture probabilities (Psub(K)) to the 172, 103 and 97 keV levels in the decay of /sup 153/Gd have been determined; these yield an electron-capture energy Qsub(EC)=245 +- 2. The K-capture probability to the 172 keV level differs significantly from that found in the literature. With these results the K-shell fluorescence yield of Eu is ..omega..sub(K)=0.935 +- 0.019.

  16. Multiple electron capture in close ion-atom collisions

    International Nuclear Information System (INIS)

    Schlachter, A.S.; Stearns, J.W.; Berkner, K.H.

    1989-01-01

    Collisions in which a fast highly charged ion passes within the orbit of K electron of a target gas atom are selected by emission of a K x-ray from the projectile or target. Measurement of the projectile charge state after the collision, in coincidence with the K x-ray, allows measurement of the charge-transfer probability during these close collisions. When the projectile velocity is approximately the same as that of target electrons, a large number of electrons can be transferred to the projectile in a single collision. The electron-capture probability is found to be a linear function of the number of vacancies in the projectile L shell for 47-MeV calcium ions in an Ar target. 18 refs., 9 figs

  17. Probabilities and energies to obtain the counting efficiency of electron-capture nuclides, KLMN model

    International Nuclear Information System (INIS)

    Casas Galiano, G.; Grau Malonda, A.

    1994-01-01

    An intelligent computer program has been developed to obtain the mathematical formulae to compute the probabilities and reduced energies of the different atomic rearrangement pathways following electron-capture decay. Creation and annihilation operators for Auger and X processes have been introduced. Taking into account the symmetries associated with each process, 262 different pathways were obtained. This model allows us to obtain the influence of the M-electron-capture in the counting efficiency when the atomic number of the nuclide is high

  18. Probabilities and energies to obtain the counting efficiency of electron-capture nuclides. KLMN model

    International Nuclear Information System (INIS)

    Galiano, G.; Grau, A.

    1994-01-01

    An intelligent computer program has been developed to obtain the mathematical formulae to compute the probabilities and reduced energies of the different atomic rearrangement pathways following electron-capture decay. Creation and annihilation operators for Auger and X processes have been introduced. Taking into account the symmetries associated with each process, 262 different pathways were obtained. This model allows us to obtain the influence of the M-electro capture in the counting efficiency when the atomic number of the nuclide is high. (Author)

  19. Alpha-particle and electron capture decay of 209Po

    International Nuclear Information System (INIS)

    Schima, F.J.; Colle, R.

    1996-01-01

    Gamma-ray and Kα X-ray emissions have been measured from a very pure 209 Po source containing less than 0.13% 208 Po activity and no detectable 210 Po (≤2 x 10 -4 %). The alpha-particle emission rate for this source has previously been determined. Data are presented that confirm alpha decay to the 205 Pb excited level at 262.8 keV, with an alpha-particle emission probability (±standard uncertainty) of 0.00559±0.00008. The ratio of K-shell electron capture to total electron capture for the second forbidden unique electron capture decay to the 896.6 keV level in 209 Bi was determined to be 0.594±0.018. The electron capture decay fraction was found to be 0.00454±0.00007, while the probabilities per decay for the 896.6, 262.8, and 260.5 keV gamma rays and the Bi Kα and Pb Kα X-rays were measured as 0.00445±0.00007, 0.00085±0.00002, 0.00254±0.00003, 0.00202±0.00005, and 0.00136±0.00005, respectively. (orig.)

  20. K-capture probabilities to 400. 56 and 279. 48 keV levels in the decay of /sup 75/Se

    Energy Technology Data Exchange (ETDEWEB)

    Singh, K; Sahota, H S

    1984-02-01

    Precisely calibrated high resolution intrinsic semiconductor detector has been used to find K-capture probabilities to 400.56 and 279.48 keV levels in the decay of /sup 75/Se. The measurement to 279.48 keV level is reported for the first time in literature.

  1. 'Mathematical model of K Capture and its implications'

    International Nuclear Information System (INIS)

    Angus, Andrew C.

    2000-01-01

    The mechanism of K Capture, the nuclear absorption of electron in the K shell, as induced by electricity, is explained in this article. Furthermore, a mathematical model of K Capture is formulated. Then, K Capture is applied to explain the negative results obtained by Steven Jones and the positive results obtained by Pons-Fleischmann in Deuterium Oxide Electrolysis Experiments. The most important implication of K Capture is the possibility of obtaining nuclear energy by fusion at low temperature from heavy water

  2. Multiple electron capture in close ion-atom collisions

    International Nuclear Information System (INIS)

    Schlachter, A.S.

    1987-10-01

    Multiple electron capture is reported for Ca 17+ in Ar. Close collisions are defined by the observation of a coincident Ca K or Ar K x-ray. A large number of electrons is transferred to the projectile in a single close collision when the Ca ion projectile is of the order of the Ar L-shell electron velocity. The cross section for electron capture is reported

  3. Interatomic Coulombic electron capture

    International Nuclear Information System (INIS)

    Gokhberg, K.; Cederbaum, L. S.

    2010-01-01

    In a previous publication [K. Gokhberg and L. S. Cederbaum, J. Phys. B 42, 231001 (2009)] we presented the interatomic Coulombic electron capture process--an efficient electron capture mechanism by atoms and ions in the presence of an environment. In the present work we derive and discuss the mechanism in detail. We demonstrate thereby that this mechanism belongs to a family of interatomic electron capture processes driven by electron correlation. In these processes the excess energy released in the capture event is transferred to the environment and used to ionize (or to excite) it. This family includes the processes where the capture is into the lowest or into an excited unoccupied orbital of an atom or ion and proceeds in step with the ionization (or excitation) of the environment, as well as the process where an intermediate autoionizing excited resonance state is formed in the capturing center which subsequently deexcites to a stable state transferring its excess energy to the environment. Detailed derivation of the asymptotic cross sections of these processes is presented. The derived expressions make clear that the environment assisted capture processes can be important for many systems. Illustrative examples are presented for a number of model systems for which the data needed to construct the various capture cross sections are available in the literature.

  4. Electrofishing capture probability of smallmouth bass in streams

    Science.gov (United States)

    Dauwalter, D.C.; Fisher, W.L.

    2007-01-01

    Abundance estimation is an integral part of understanding the ecology and advancing the management of fish populations and communities. Mark-recapture and removal methods are commonly used to estimate the abundance of stream fishes. Alternatively, abundance can be estimated by dividing the number of individuals sampled by the probability of capture. We conducted a mark-recapture study and used multiple repeated-measures logistic regression to determine the influence of fish size, sampling procedures, and stream habitat variables on the cumulative capture probability for smallmouth bass Micropterus dolomieu in two eastern Oklahoma streams. The predicted capture probability was used to adjust the number of individuals sampled to obtain abundance estimates. The observed capture probabilities were higher for larger fish and decreased with successive electrofishing passes for larger fish only. Model selection suggested that the number of electrofishing passes, fish length, and mean thalweg depth affected capture probabilities the most; there was little evidence for any effect of electrofishing power density and woody debris density on capture probability. Leave-one-out cross validation showed that the cumulative capture probability model predicts smallmouth abundance accurately. ?? Copyright by the American Fisheries Society 2007.

  5. Electron capture and stellar collapse

    International Nuclear Information System (INIS)

    Chung, K.C.

    1979-01-01

    In order, to investigate the function of electron capture in the phenomenon of pre-supernovae gravitacional collapse, an hydrodynamic caculation was carried out, coupling capture, decay and nuclear reaction equation system. A star simplified model (homogeneous model) was adopted using fermi ideal gas approximation for tthe sea of free electrons and neutrons. The non simplified treatment from quasi-static evolution to collapse is presented. The capture and beta decay rates, as wellas neutron delayed emission, were calculated by beta decay crude theory, while the other reaction rates were determined by usual theories. The preliminary results are presented. (M.C.K.) [pt

  6. Simultaneous electron capture and excitation in ion-atom collisions

    International Nuclear Information System (INIS)

    Tanis, J.A.; Bernstein, E.M.; Graham, W.G.; Clark, M.; Shafroth, S.M.; Johnson, B.M.; Jones, K.; Meron, M.

    1982-01-01

    A review of recent efforts to observe simultaneous electron capture-and-K-shell excitation in ion-atom collisions is presented. This process which has been referred to as resonant-transfer-and-excitation (RTE), is qualitatively analogous to dielectronic recombination (inverse Auger transition) in free-electron-ion collisions, and, hence, is expected to be resonant. Experimentally, events having the correct signature for simultaneous capture-and-excitation are isolated by detecting projectile K x rays in coincidence with ions which capture a single electron. In a recent experiment involving 70-160 MeV S 13+ ions incident on Ar, a maximum was observed in the yield of projectile K x rays associated with electron capture. This maximum is attributed to simultaneous capture - and excitation. The position (120 MeV) and width (60 MeV) of the observed maximum are in good agreement with theoretical calculations. The data indicate that RTE is an important mechanism for inner-shell vacancy production in the energy range studied

  7. Resonant Electron capture for be-like ions with K- and L- shell excitations

    International Nuclear Information System (INIS)

    Hanafy, H.

    2005-01-01

    Resonant electron capture in electron-ion collisions is known as dielectronic recombination (DR). It was proved that, DR dominants usually over radiative recombination (RR) at high energy. Since 1980's, DR is considered a very important process in thermal plasma. The DR is an effective process in self-cooling and ionization balance as well as plasma modeling. Experimental works are still carried out to understand the trends of DR process. In the present work, DR cross sections are calculated for Be-like ions with K- and L- shell excitations. It is found that, DR cross sections increase as the effective charge (Zeff) increases for both types of excitations. DR rates coefficient in case of L-shell excitation is found to be five times larger than that of K-shell excitation

  8. Radiative electron capture by channeled ions

    International Nuclear Information System (INIS)

    Pitarke, J.M.; Ritchie, R.H.; Tennessee Univ., Knoxville, TN

    1989-01-01

    Considerable experimental data have been accumulated relative to the emission of photons accompanying electron capture by swift, highly stripped atoms penetrating crystalline matter under channeling conditions. Recent data suggest that the photon energies may be less than that expected from simple considerations of transitions from the valence band of the solid to hydrogenic states on the moving ion. We have studied theoretically the impact parameter dependence of the radiative electron capture (REC) process, the effect of the ion's wake and the effect of capture from inner shells of the solid on the photon emission probability, using a statistical approach. Numerical comparisons of our results with experiment are made. 13 refs., 6 figs

  9. Electron capture rate of a composite of partially ionized atomic nuclei

    International Nuclear Information System (INIS)

    Yokoi, K.; Takahashi, K.

    1979-01-01

    Electron captures (or more generally β-transitions) are known to play key roles at various stages of stellar evolution and in many nucleosynthesis processes. With decreasing temperatures and densities, the bound electron captures start to compete with the free electron captures, and eventually in the low-temperature, low-density limit the total capture rate shall converge to that of the orbital electrons observed in laboratory. The authors calculate the occupation probabilities of the electron orbits and the electron capture rates in a mixture of atoms and ions which are supposedly under a chemical equilibrium. (orig./AH)

  10. CDW (continuum distorted wave) type approximation for electron capture at large angles

    International Nuclear Information System (INIS)

    Fojon, O.A.; Maidagan, J.M.

    1990-01-01

    A calculation is made for the probability of electron capture in shell K at great angles using a second order symmetrical model used related to the continuum distorted wave (CDW) approximation. The influence of Coulomb distortion of nuclei is studied and compared with OBK and CIS type calculations. Numerical results are compared with experimental results of the collision of H + on C at intermediate energies. (Author). 19 refs., 2 figs

  11. Single electron capture measurements in collisions of K{sup +} on N{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Alarcón, F.B. [Laboratorio de Espectroscopia, Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62210 Cuernavaca, Morelos (Mexico); Fuentes, B.E., E-mail: beatriz.fuentes@ciencias.unam.mx [Facultad de Ciencias, Universidad Nacional Autónoma de México, Circuito Exterior, Cd. Universitaria, 04510 México D.F. (Mexico); Martínez, H. [Laboratorio de Espectroscopia, Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62210 Cuernavaca, Morelos (Mexico); Yousif, F.B. [Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Av. Universidad #1000, Col. Chamilpa, C.P. 62210, Cuernavaca, Morelos (Mexico)

    2014-08-01

    Absolute total charge transfer cross sections have been measured for K{sup +}–N{sub 2} collisions, at impact energies between 1.0 and 3.5 keV. The charge transfer cross sections show a monotonic increasing behaviour as a function of the incident energy. Agreement with other groups is observed as the present measurements extend to lower energies. A semi-empirical calculation shows a similar behaviour to the present data with respect to the electron capture cross sections as a function of energy.

  12. Towards saturation of the electron-capture delayed fission probability: The new isotopes 240Es and 236Bk

    Directory of Open Access Journals (Sweden)

    J. Konki

    2017-01-01

    Full Text Available The new neutron-deficient nuclei 240Es and 236Bk were synthesised at the gas-filled recoil separator RITU. They were identified by their radioactive decay chains starting from 240Es produced in the fusion–evaporation reaction 209Bi(34S,3n240Es. Half-lives of 6(2s and 22−6+13s were obtained for 240Es and 236Bk, respectively. Two groups of α particles with energies Eα=8.19(3MeV and 8.09(3MeV were unambiguously assigned to 240Es. Electron-capture delayed fission branches with probabilities of 0.16(6 and 0.04(2 were measured for 240Es and 236Bk, respectively. These new data show a continuation of the exponential increase of ECDF probabilities in more neutron-deficient isotopes.

  13. Radiative electron capture into the K-, L-, and M-shell of decelerated, hydrogenic Ge projectiles

    International Nuclear Information System (INIS)

    Stoehlker, T.; Kozhuharov, C.; Livingston, A.E.; Mokler, P.H.; Stachura, Z.; Warczak, A.

    1991-12-01

    Radiative Electron Capture (REC) in 4 to 12 MeV/u Ge 31+ →H 2 collisions has been studied using an X-ray/particle coincidence technique. This technique allowed a systematic investigation of K-shell REC as well as a separation of REC into the projectile L- and M-shells. The cross sections are discussed within a general scaling picture based on the reduced projectile velocity. (orig.)

  14. Orbital electron capture measurements with an internal-source spectrometer

    International Nuclear Information System (INIS)

    Gerner, C.P.

    1978-01-01

    Electron-capture measurements have been performed on 131 Ba and on 106 Agsup(m). For 131 Ba the L/K-and M/L-capture rations of the allowed decay have been measured to the 1048 keV level in 131 Cs. The Qsub(EC) value, the exchange- and overlap-correction factors Xsup(L/K) and Xsup(M/L) and the reduced capture ratios have been determined. For 106 Agsup(m) the L/K-capture ratio of the allowed decay has been measured to the 2757 keV level in 106 Pd. The Q value, the exchange- and overlap-correction factor Xsup(L/K) and the reduced L/K- capture ratio have been derived. The measurements indicate that agreement between experimentally determined capture ratios and exchange-corrected theoretical predictions is fairly good, both for allowed and for first-forbidden non-unique transitions. (Auth./C.F.)

  15. Correlated double electron capture in slow, highly charged ion-atom collisions

    International Nuclear Information System (INIS)

    Stolterfoht, N.; Havener, C.C.; Phaneuf, R.A.; Swenson, J.K.; Shafroth, S.M.; Meyer, F.W.

    1986-01-01

    Recent measurements of autoionization electrons produced in slow, highly charged ion-atom collisions are reviewed. Mechanisms for double electron capture into equivalent and nonequivalent configurations are analyzed by comparing the probabilities for the creation of L 1 L 23 X Coster Kronig electrons and L-Auger electrons. It is shown that the production of the Coster-Kronig electrons is due to electron correlation effects whose analysis leads beyond the independent-particle model. The importance of correlation effects on different capture mechanisms is discussed. 28 refs., 6 figs

  16. Electron capture in asymmetric collisions

    International Nuclear Information System (INIS)

    Graviele, M.S.; Miraglia, J.E.

    1988-01-01

    It is calculated the electronic capture of K shell by protons using the on-shell impulsive wave functions, exact and eikonal, in the initial and final channels respectively. Both wave functions are normalized and have the correct asyntotic conditions. A good agreement to the experimental data is found. (A.C.A.S.) [pt

  17. Correlated double electron capture in slow, highly charged ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Stolterfoht, N.; Havener, C.C.; Phaneuf, R.A.; Swenson, J.K.; Shafroth, S.M.; Meyer, F.W.

    1986-01-01

    Recent measurements of autoionization electrons produced in slow, highly charged ion-atom collisions are reviewed. Mechanisms for double electron capture into equivalent and nonequivalent configurations are analyzed by comparing the probabilities for the creation of L/sub 1/L/sub 23/X Coster Kronig electrons and L-Auger electrons. It is shown that the production of the Coster-Kronig electrons is due to electron correlation effects whose analysis leads beyond the independent-particle model. The importance of correlation effects on different capture mechanisms is discussed. 28 refs., 6 figs.

  18. Ultra-fast electron capture by electrosterically-stabilized gold nanoparticles.

    Science.gov (United States)

    Ghandi, Khashayar; Findlater, Alexander D; Mahimwalla, Zahid; MacNeil, Connor S; Awoonor-Williams, Ernest; Zahariev, Federico; Gordon, Mark S

    2015-07-21

    Ultra-fast pre-solvated electron capture has been observed for aqueous solutions of room-temperature ionic liquid (RTIL) surface-stabilized gold nanoparticles (AuNPs; ∼9 nm). The extraordinarily large inverse temperature dependent rate constants (k(e)∼ 5 × 10(14) M(-1) s(-1)) measured for the capture of electrons in solution suggest electron capture by the AuNP surface that is on the timescale of, and therefore in competition with, electron solvation and electron-cation recombination reactions. The observed electron transfer rates challenge the conventional notion that radiation induced biological damage would be enhanced in the presence of AuNPs. On the contrary, AuNPs stabilized by non-covalently bonded ligands demonstrate the potential to quench radiation-induced electrons, indicating potential applications in fields ranging from radiation therapy to heterogeneous catalysis.

  19. Radiative electron capture

    International Nuclear Information System (INIS)

    Biggerstaff, J.A.; Appleton, B.R.; Datz, S.; Moak, C.D.; Neelavathi, V.N.; Noggle, T.S.; Ritchie, R.H.; VerBeek, H.

    1975-01-01

    Some data are presented for radiative electron capture by fast moving ions. The radiative electron capture spectrum is shown for O 8+ in Ag, along with the energy dependence of the capture cross-section. A discrepancy between earlier data, theoretical prediction, and the present data is pointed out. (3 figs) (U.S.)

  20. Electron capture by highly charged ions from surfaces and gases

    International Nuclear Information System (INIS)

    Allen, F.

    2008-01-01

    In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar 17+ and Ar 18+ ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu -1 , charge-selected and then decelerated down to 5 eVu -1 for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar 17+ and Ar 18+ ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu -1 , charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar 16+ and Xe 44+ and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

  1. Genetic effects of decay by electron capture of radionuclides in yeasts cell

    International Nuclear Information System (INIS)

    Gracheva, L.M.; Korolev, V.G.

    1984-01-01

    Regularities of genetic effect on the yeast cell Saccharomyces cerevisiae, incorporated radionuclides decaying according to the scheme of k-capture- 7 Be, 54 Mn, 85 Sr are studied. It is known that this type of decay models the ionization of internal electron shells of atoms which is most probable when a cell is affected by external ionizing radiation. It is shown that the decay of radionuclides connecting with a DNA molecule in a cell according to the scheme of D-capture brings about a strong lethal effect. The relative mutagenic efficiency is much lower than that for gamma-radiation and many radionuclides decaying according to the scheme of B-decay. In the mutation spectrum induced by these radionuclides the increase in the number of mutations of the reading frame shift type is observed

  2. Electron capture by highly charged ions from surfaces and gases

    Energy Technology Data Exchange (ETDEWEB)

    Allen, F.

    2008-01-11

    In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar{sup 17+} and Ar{sup 18+} ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu{sup -1}, charge-selected and then decelerated down to 5 eVu{sup -1} for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar{sup 17+} and Ar{sup 18+} ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu{sup -1}, charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar{sup 16+} and Xe{sup 44+} and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

  3. Dynamic plasma screening effects on electron capture process in hydrogenic ion fully stripped ion collisions in dense plasmas

    International Nuclear Information System (INIS)

    Jung, Y.

    1997-01-01

    In dense plasmas, dynamic plasma screening effects are investigated on electron capture from hydrogenic ions by past fully stripped ions. The classical Bohr Lindhard model has been applied to obtain the electron capture probability. The interaction potential in dense plasmas is represented in terms of the longitudinal dielectric function. The classical straight-line trajectory approximation is applied to the motion of the projectile ion in order to visualize the electron capture probability as a function of the impact parameter, projectile energy, and plasma parameters. The electron capture probability including the dynamic plasma screening effect is always greater than that including the static plasma screening effect. When the projectile velocity is smaller than the electron thermal velocity, the dynamic polarization screening effect becomes the static plasma screening effect. When the projectile velocity is greater than the plasma electron thermal velocity, the interaction potential is almost unshielded. The difference between the dynamic and static plasma screening effects is more significant for low energy projectiles. It is found that the static screening formula obtained by the Debye Hueckel model overestimates the plasma screening effects on the electron capture processes in dense plasmas. copyright 1997 American Institute of Physics

  4. Atomic and nuclear parameters of single electron capture decaying nuclides

    International Nuclear Information System (INIS)

    Grau, A.

    1981-01-01

    Atomic and nuclear parameters of the following nuclides which decay by electron capture have been calculated: 37 A r, 41 C a, 49 V , 53 M n, 55 F e,59 N i, 68Ge,82 S r, 97 T c, 118 T e, 131 C s, 137 L a, 140 N d, 157 T b, 165 E r, 193 p t, 194 H g, and 205 P h The evaluation rules are included in the first part of the paper. The values and the associated uncertainties of the following parameters have been tabulated: decay energy, electron capture probabilities, fluorescence yield, electron emission and X-ray emission. (Author) 27 refs

  5. Probabilities and energies to obtain the counting efficiency of electron-capture nuclides. KLMN model; Probabilidades y energias de reestructuracion atomica subsiguientes a la captura electronica. Modelo KLMN

    Energy Technology Data Exchange (ETDEWEB)

    Galiano, G.; Grau, A.

    1994-07-01

    An intelligent computer program has been developed to obtain the mathematical formulae to compute the probabilities and reduced energies of the different atomic rearrangement pathways following electron-capture decay. Creation and annihilation operators for Auger and X processes have been introduced. Taking into account the symmetries associated with each process, 262 different pathways were obtained. This model allows us to obtain the influence of the M-electro capture in the counting efficiency when the atomic number of the nuclide is high. (Author)

  6. Low-Energy Nuclear Reactions Resulting as Picometer Interactions with Similarity to K-Shell Electron Capture

    Science.gov (United States)

    Hora, H.; Miley, G. H.; Li, X. Z.; Kelly, J. C.; Osman, F.

    2006-02-01

    Since the appeal by Brian Josephson at the meeting of the Nobel Laureates July 2004, it seems to be indicated to summarize the following serious, reproducible and confirmed observations on reactions of protons or deuterons incorporated in host metals such as palladium. Some reflections to Rutherford's discovery of nuclear physics, the Cockroft-Oliphant discovery of anomalous low-energy fusion reactions and the chemist Hahn's discovery of fission had to be included. Using gaseous atmosphere or discharges between palladium targets, rather significant results were seen e.g. from the "life after death" heat production of such high values per host atom that only nuclear reactions can be involved. This supports the earlier evaluation of neutron generation in fully reversible experiments with gas discharges hinting that a reasonable screening effect - preferably in the swimming electron layer - may lead to reactions at nuclear distances d of picometers with reaction probability times U of about megaseconds similar to the K-shell capture radioactivity. Further electrolytic experiments led to low-energy nuclear reactions (LENR) where the involvement of pollution could be excluded from the appearance of very seldom rare earth elements. A basically new theory for DD cross-sections is used to confirm the picometer-megasecond reactions of cold fusion. Other theoretical aspects are given from measured heavy element distributions similar to the standard abundance distribution, SAD, in the Universe with consequences on endothermic heavy nuclei generation, magic numbers and to quark-gluon plasmas.

  7. Low-energy nuclear reactions resulting as parametric interactions with similarity to K-shell electron capture

    International Nuclear Information System (INIS)

    Hora, H.; Miley, G.H.; Li, X.Z.; Kelly, J.C.; Osman, F.

    2006-01-01

    Since the appeal by Brian Josephson at the meeting of the Nobel Laureates July 2004, it seems to be indicated to summarize the following serious, reproducible and confirmed observations on reactions of protons of deuterons incorporated in host metals such as palladium. Some reflections to Rutherford's discovery of nuclear physics, the Cockcroft Oliphant discovery of anomalous low-energy fusion reactions and the chemist Hahn's discovery of fission had to be included. Using gaseous atmosphere or discharges between palladium targets, rather significant results were seen e.g. from the 'life after death' heat production of such high values per host atom that only nuclear reactions can be involved. This supports the earlier evaluation of neutron generation in fully reversible experiments with gas discharges hinting that a reasonable screening effect - preferably in the swimming electron layer - may lead to reactions at nuclear distances d of pico-meters with reaction probability times U of about mega-seconds similar to the K-shell capture radioactivity. Further electrolytic experiments led to low-energy nuclear reactions (LENR) where the involvement of pollution could be excluded from the appearance of very seldom rare earth elements. A basically new theory for DD cross-sections is used to confirm the pico-meter- mega-second reactions of cold fusion. Other theoretical aspects are given from measured heavy element distributions similar to the standard abundance distribution, SAD, in the Universe with consequences on endothermic heavy nuclei generation, magic numbers and to quark-gluon plasmas. (authors)

  8. Electronic radiative capture in solid targets

    International Nuclear Information System (INIS)

    Pregliasco, R.; Nemirovsky, I.; Suarez, S.

    1988-01-01

    X-ray spectra originating from electron radiative capture from aluminium target to K shell on F 9+ and F 8+ beams with 115MeV are studied. Using an electrostatic analyzer, it was obtained the charge fractions Fi to aluminiun thicknesses of 39 and 58 micrograms/cm 2 . These thicknesses are determined by the stopping power of alpha particles. (A.C.A.S.) [pt

  9. The electron capture in 163Ho experiment - ECHo

    Science.gov (United States)

    Gastaldo, L.; Blaum, K.; Chrysalidis, K.; Day Goodacre, T.; Domula, A.; Door, M.; Dorrer, H.; Düllmann, Ch. E.; Eberhardt, K.; Eliseev, S.; Enss, C.; Faessler, A.; Filianin, P.; Fleischmann, A.; Fonnesu, D.; Gamer, L.; Haas, R.; Hassel, C.; Hengstler, D.; Jochum, J.; Johnston, K.; Kebschull, U.; Kempf, S.; Kieck, T.; Köster, U.; Lahiri, S.; Maiti, M.; Mantegazzini, F.; Marsh, B.; Neroutsos, P.; Novikov, Yu. N.; Ranitzsch, P. C. O.; Rothe, S.; Rischka, A.; Saenz, A.; Sander, O.; Schneider, F.; Scholl, S.; Schüssler, R. X.; Schweiger, Ch.; Simkovic, F.; Stora, T.; Szücs, Z.; Türler, A.; Veinhard, M.; Weber, M.; Wegner, M.; Wendt, K.; Zuber, K.

    2017-06-01

    Neutrinos, and in particular their tiny but non-vanishing masses, can be considered one of the doors towards physics beyond the Standard Model. Precision measurements of the kinematics of weak interactions, in particular of the 3H β-decay and the 163Ho electron capture (EC), represent the only model independent approach to determine the absolute scale of neutrino masses. The electron capture in 163Ho experiment, ECHo, is designed to reach sub-eV sensitivity on the electron neutrino mass by means of the analysis of the calorimetrically measured electron capture spectrum of the nuclide 163Ho. The maximum energy available for this decay, about 2.8 keV, constrains the type of detectors that can be used. Arrays of low temperature metallic magnetic calorimeters (MMCs) are being developed to measure the 163Ho EC spectrum with energy resolution below 3 eV FWHM and with a time resolution below 1 μs. To achieve the sub-eV sensitivity on the electron neutrino mass, together with the detector optimization, the availability of large ultra-pure 163Ho samples, the identification and suppression of background sources as well as the precise parametrization of the 163Ho EC spectrum are of utmost importance. The high-energy resolution 163Ho spectra measured with the first MMC prototypes with ion-implanted 163Ho set the basis for the ECHo experiment. We describe the conceptual design of ECHo and motivate the strategies we have adopted to carry on the present medium scale experiment, ECHo-1K. In this experiment, the use of 1 kBq 163Ho will allow to reach a neutrino mass sensitivity below 10 eV/ c 2. We then discuss how the results being achieved in ECHo-1k will guide the design of the next stage of the ECHo experiment, ECHo-1M, where a source of the order of 1 MBq 163Ho embedded in large MMCs arrays will allow to reach sub-eV sensitivity on the electron neutrino mass.

  10. Calculations on Electron Capture in Low Energy Ion-Molecule Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Stancil, P.C. [Oak Ridge National Lab., TN (United States); Zygelman, B. [W.M. Keck Lab. for Computational Physics, Univ. of Nevada, Las Vegas, NV (United States); Kirby, K. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

    1997-12-31

    Recent progress on the application of a quantal, molecular-orbital, close-coupling approach to the calculation of electron capture in collisions of multiply charged ions with molecules is discussed. Preliminary results for single electron capture by N{sup 2+} with H{sub 2} are presented. Electron capture by multiply charged ions colliding with H{sub 2} is an important process in laboratory and astrophysical plasmas. It provides a recombination mechanism for multiply charged ions in x-ray ionized astronomical environments which may have sparse electron and atomic hydrogen abundances. In the divertor region of a tokamak fusion device, charge exchange of impurity ions with H{sub 2} plays a role in the ionization balance and the production of radiative energy loss leading to cooling, X-ray and ultraviolet auroral emission from Jupiter is believed to be due to charge exchange of O and S ions with H{sub 2} in the Jovian atmosphere. Solar wind ions interacting with cometary molecules may have produced the x-rays observed from Comet Hyakutake. In order to model and understand the behavior of these environments, it is necessary to obtain total, electronic state-selective (ESS), and vibrational (or rotational) state-selective (VSS) capture cross sections for collision energies as low as 10 meV/amu to as high as 100 keV/amu in some instances. Fortunately, charge transfer with molecular targets has received considerable experimental attention. Numerous measurements have been made with flow tubes, ion traps, and ion beams. Flow tube and ion trap studies generally provide information on rate coefficients for temperatures between 800 K and 20,000 K. In this article, we report on the progress of our group in implementing a quantum-mechanical Molecular Orbital Close Coupling (MOCC) approach to the study of electron capture by multiply charged ions in collisions with molecules. We illustrate this with a preliminary investigation of Single Electron Capture (SEC) by N{sup 2+} with H

  11. Low-energy nuclear reactions resulting as parametric interactions with similarity to K-shell electron capture

    Energy Technology Data Exchange (ETDEWEB)

    Hora, H. [University of New South Wales, Sydney 2052 (Australia); Miley, G.H. [Fusion Studies Laboratory, University of Illinois, Urbana, lL 61801 (United States); Li, X.Z. [Physics Department, Tsinghua University, Beijing 100084 (China); Kelly, J.C. [School of Physics, Sydney University, Sydney 2006 (Australia); Osman, F. [University of Western Sydney, Penrith-Soutti, NSW 1791 (Australia)

    2006-07-01

    Since the appeal by Brian Josephson at the meeting of the Nobel Laureates July 2004, it seems to be indicated to summarize the following serious, reproducible and confirmed observations on reactions of protons of deuterons incorporated in host metals such as palladium. Some reflections to Rutherford's discovery of nuclear physics, the Cockcroft Oliphant discovery of anomalous low-energy fusion reactions and the chemist Hahn's discovery of fission had to be included. Using gaseous atmosphere or discharges between palladium targets, rather significant results were seen e.g. from the 'life after death' heat production of such high values per host atom that only nuclear reactions can be involved. This supports the earlier evaluation of neutron generation in fully reversible experiments with gas discharges hinting that a reasonable screening effect - preferably in the swimming electron layer - may lead to reactions at nuclear distances d of pico-meters with reaction probability times U of about mega-seconds similar to the K-shell capture radioactivity. Further electrolytic experiments led to low-energy nuclear reactions (LENR) where the involvement of pollution could be excluded from the appearance of very seldom rare earth elements. A basically new theory for DD cross-sections is used to confirm the pico-meter- mega-second reactions of cold fusion. Other theoretical aspects are given from measured heavy element distributions similar to the standard abundance distribution, SAD, in the Universe with consequences on endothermic heavy nuclei generation, magic numbers and to quark-gluon plasmas. (authors)

  12. Interatomic Coulombic electron capture in atomic, molecular, and quantum dot systems

    Directory of Open Access Journals (Sweden)

    Bande Annika

    2015-01-01

    Full Text Available The interatomic Coulombic electron capture (ICEC process has recently been predicted theoretically for clusters of atoms and molecules. For an atom A capturing an electron e(ε it competes with the well known photorecombination, because in an environment of neutral or anionic neighboring atoms B, A can transfer its excess energy in the ultrafast ICEC process to B which is then ionized. The cross section for e(ε + A + B → A− + B+ + e(ε′ has been obtained in an asymptotic approximation based on scattering theory for several clusters [1,2]. It was found that ICEC starts dominating the PR for distances among participating species of nanometers and lower. Therefore, we believe that the ICEC process might be of importance in the atmosphere, in biological systems, plasmas, or in nanostructured materials. As an example for the latter, ICEC has been investigated by means of electron dynamics in a model potential for semiconductor double quantum dots (QDs [3]. In the simplest case one QD captures an electron while the outgoing electron is emitted from the other. The reaction probability for this process was found to be relatively large.

  13. Multiple capture investigated by coincident electron spectroscopy in X7++Ar, at 70 keV

    International Nuclear Information System (INIS)

    Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A.

    1999-01-01

    The multiple electron capture in N 7+ + Ar and F 7+ (1s 2 ) + Ar systems is investigated at 70 keV with a new electron-recoil ion charge coincidence experiment. The whole electron energy range has been studied. Up to six electrons are found to be captured into autoionizing states. The recoil ion charge distribution associated with the emission of electrons is similar for both systems and found to be in good agreement with the prediction of Niehaus's model roughly adapted to take into account autoionizing cascades. New findings for the coincident double and triple captures are briefly discussed. A capture of an inner L-shell electron of Ar into the K-shell of the projectile is also observed in N 7+ + Ar collisions. (orig.)

  14. Transition probabilities between levels of K and K+

    International Nuclear Information System (INIS)

    Campos Gutierrez, J.; Martin Vicente, A.

    1984-01-01

    In this work transition probabilities between Ievels of n < 11 for K and for the known of K+ are calculated. Two computer programs based on the Coulomb approximation and the most suitable coupling schemes has been used. Lifetimes of all these levels are also calculated. (Author)

  15. Radiative double electron capture in fast heavy ion-atom collisions

    International Nuclear Information System (INIS)

    Yakhontov, V.L.; Amusia, M.Ya.

    1996-01-01

    Two-electron capture with emission of a single photon (TESP) in collisions of highly charged ions with light atoms is considered. Such a process is actually a time-reversed double photoionization but occurring at specific kinematics. In the lowest order in the inter-electron interaction, the TESP probability is determined by two diagrams which are evaluated analytically by means of the Coulomb Green function. The calculated ratio of the TESP and single recombination cross sections is in fair agreement with the data obtained in the recent experimental study of this phenomena. (orig.)

  16. Gamow-Teller strength distributions and electron capture rates for 55Co and 56Ni

    International Nuclear Information System (INIS)

    Nabi, Jameel-Un; Rahman, Muneeb-Ur

    2005-01-01

    The Gamow-Teller strength (GT) distributions and electron capture rates on 55 Co and 56 Ni have been calculated using the proton-neutron quasiparticle random phase approximation theory. We calculate these weak interaction mediated rates over a wide temperature (0.01x10 9 -30x10 9 K) and density (10-10 11 gcm -3 ) domain. Electron capture process is one of the essential ingredients involved in the complex dynamics of supernova explosion. Our calculations of electron capture rates show differences with the reported shell model diagonalization approach calculations and are comparatively enhanced at presupernova temperatures. We note that the GT strength is fragmented over many final states

  17. Entrained Flow Reactor Study of K-Capture by Solid Additives

    DEFF Research Database (Denmark)

    Wang, Guoliang; Jensen, Peter Arendt; Wu, Hao

    2016-01-01

    are collected from the cyclone and filter. The K-capture reaction is evaluated by determining the fraction of water-insoluble K in the products. The results showed that KCl can effectively be captured by kaolin and coal fly ash, forming water-insoluble K-aluminosilicates. The amount of K, captured per gram...

  18. Studing electronic structure of water molecules in aquocomplexes by the method of pions minus capture by hydrogen

    International Nuclear Information System (INIS)

    Dezhi, I.; Krumshtejn, Z.V.; Molnar, B.; Petrukhin, V.I.; Rybakov, V.N.; Suvorov, V.M.; Khorvat, D.; Tsisek, Z.; Yutlandov, I.A.

    1980-01-01

    Using the effect of electron shell state on π-meson capture by chemically bound hydrogen studied has been change of electron density in hydrogen atoms of water molecules bound into aquocomplexes. The fact of depression of π-meson capture probability by hydrogen of water in aquocomplexes has been established. The magnitudes of depression indicate essential decrease of electron density in a hydrogen atom of coordinated water. Interaction of ligands with oxygen-containing anions also essentially contributes to a magnitude of depression

  19. Multiple capture investigated by coincident electron spectroscopy in X{sup 7+}+Ar, at 70 keV

    Energy Technology Data Exchange (ETDEWEB)

    Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A. [Universite Paul Sabatier, Toulouse (France). Lab. Collisions-Agregats-Reactivite

    1999-11-01

    The multiple electron capture in N{sup 7+} + Ar and F{sup 7+}(1s{sup 2}) + Ar systems is investigated at 70 keV with a new electron-recoil ion charge coincidence experiment. The whole electron energy range has been studied. Up to six electrons are found to be captured into autoionizing states. The recoil ion charge distribution associated with the emission of electrons is similar for both systems and found to be in good agreement with the prediction of Niehaus`s model roughly adapted to take into account autoionizing cascades. New findings for the coincident double and triple captures are briefly discussed. A capture of an inner L-shell electron of Ar into the K-shell of the projectile is also observed in N{sup 7+} + Ar collisions. (orig.) 10 refs.

  20. K-forbidden transition probabilities

    International Nuclear Information System (INIS)

    Saitoh, T.R.; Sletten, G.; Bark, R.A.; Hagemann, G.B.; Herskind, B.; Saitoh-Hashimoto, N.; Tsukuba Univ., Ibaraki

    2000-01-01

    Reduced hindrance factors of K-forbidden transitions are compiled for nuclei with A∝180 where γ-vibrational states are observed. Correlations between these reduced hindrance factors and Coriolis forces, statistical level mixing and γ-softness have been studied. It is demonstrated that the K-forbidden transition probabilities are related to γ-softness. The decay of the high-K bandheads has been studied by means of the two-state mixing, which would be induced by the γ-softness, with the use of a number of K-forbidden transitions compiled in the present work, where high-K bandheads are depopulated by both E2 and ΔI=1 transitions. The validity of the two-state mixing scheme has been examined by using the proposed identity of the B(M1)/B(E2) ratios of transitions depopulating high-K bandheads and levels of low-K bands. A break down of the identity might indicate that other levels would mediate transitions between high- and low-K states. (orig.)

  1. Sampling the stream landscape: Improving the applicability of an ecoregion-level capture probability model for stream fishes

    Science.gov (United States)

    Mollenhauer, Robert; Mouser, Joshua B.; Brewer, Shannon K.

    2018-01-01

    Temporal and spatial variability in streams result in heterogeneous gear capture probability (i.e., the proportion of available individuals identified) that confounds interpretation of data used to monitor fish abundance. We modeled tow-barge electrofishing capture probability at multiple spatial scales for nine Ozark Highland stream fishes. In addition to fish size, we identified seven reach-scale environmental characteristics associated with variable capture probability: stream discharge, water depth, conductivity, water clarity, emergent vegetation, wetted width–depth ratio, and proportion of riffle habitat. The magnitude of the relationship between capture probability and both discharge and depth varied among stream fishes. We also identified lithological characteristics among stream segments as a coarse-scale source of variable capture probability. The resulting capture probability model can be used to adjust catch data and derive reach-scale absolute abundance estimates across a wide range of sampling conditions with similar effort as used in more traditional fisheries surveys (i.e., catch per unit effort). Adjusting catch data based on variable capture probability improves the comparability of data sets, thus promoting both well-informed conservation and management decisions and advances in stream-fish ecology.

  2. Radiative double-electron capture in collisions of fast heavy ions with solid carbon targets

    International Nuclear Information System (INIS)

    Yakhontov, V.L.; Amusia, M.Y.

    1997-01-01

    Two-electron capture with an emission of a single photon (TESP) in collisions of highly charged ions with light atoms is considered. Such a process is actually a time-reversed double photoionization but occurring at specific kinematics. In the lowest order in the interelectron interaction, the TESP probability is determined by two diagrams which are evaluated analytically by means of the Coulomb Green close-quote s function. The calculated ratio of the radiative double-electron capture and single recombination cross sections is in fair agreement with the data obtained in the recent experimental study of this phenomenon. copyright 1997 The American Physical Society

  3. CDW-EIS model for single-electron capture in ion-atom collisions involving multielectronic targets

    International Nuclear Information System (INIS)

    Abufager, P N; MartInez, A E; Rivarola, R D; Fainstein, P D

    2004-01-01

    A generalization of the continuum distorted wave eikonal initial state (CDW-EIS) approximation, for the description of single-electron capture in ion-atom collisions involving multielectronic targets is presented. This approximation is developed within the framework of the independent electron model taking particular care of the representation of the bound and continuum target states. Total cross sections for single-electron capture from the K-shell of He, Ne and Ar noble gases by impact of bare ions are calculated. Present results are compared to previous CDW-EIS ones and to experimental data

  4. Model of electron capture in low-temperature glasses

    International Nuclear Information System (INIS)

    Bartczak, W.M.; Swiatla, D.; Kroh, J.

    1983-01-01

    The new model of electron capture by a statistical variety of traps in glassy matrices is proposed. The electron capture is interpreted as the radiationless transition (assisted by multiphonon emission) of the mobile electron to the localized state in the trap. The conception of 'unfair' and 'fair' traps is introduced. The 'unfair' trap captures the mobile electron by the shallow excited state. In contrast, the 'fair' trap captures the electron by the ground state. The model calculations of the statistical distributions of the occupied electron traps are presented and discussed with respect to experimental results. (author)

  5. EVOLUTION OF PROGENITORS FOR ELECTRON CAPTURE SUPERNOVAE

    International Nuclear Information System (INIS)

    Takahashi, Koh; Umeda, Hideyuki; Yoshida, Takashi

    2013-01-01

    We provide progenitor models for electron capture supernovae (ECSNe) with detailed evolutionary calculation. We include minor electron capture nuclei using a large nuclear reaction network with updated reaction rates. For electron capture, the Coulomb correction of rates is treated and the contribution from neutron-rich isotopes is taken into account in each nuclear statistical equilibrium (NSE) composition. We calculate the evolution of the most massive super asymptotic giant branch stars and show that these stars undergo off-center carbon burning and form ONe cores at the center. These cores become heavier up to the critical mass of 1.367 M ☉ and keep contracting even after the initiation of O+Ne deflagration. Inclusion of minor electron capture nuclei causes convective URCA cooling during the contraction phase, but the effect on the progenitor evolution is small. On the other hand, electron capture by neutron-rich isotopes in the NSE region has a more significant effect. We discuss the uniqueness of the critical core mass for ECSNe and the effect of wind mass loss on the plausibility of our models for ECSN progenitors.

  6. Capture dynamics of hot electrons on quantum dots in RTDs studied by noise measurement

    International Nuclear Information System (INIS)

    Hees, S S; Kardynal, B E; Shields, A J; Farrer, I; Ritchie, D A

    2008-01-01

    We investigate the noise in quantum dot resonant tunnelling diodes (QDRTDs), where the quantum dots (QDs) placed in the collector experience electric fields that vary in a wide range. The trapping/detrapping of electrons on the QDs dominated the measured electrical noise. The model that we derived for the noise explains the experimental data well. The QD capture cross-section is one to two orders of magnitude smaller than the physical size of the QDs due to the reduced probability of capturing a hot electron on the QD. The model is a powerful tool to design the noise characteristics of QDRTD single photon-detectors

  7. Effect of collective response on electron capture and excitation in collisions of highly charged ions with fullerenes.

    Science.gov (United States)

    Kadhane, U; Misra, D; Singh, Y P; Tribedi, Lokesh C

    2003-03-07

    Projectile deexcitation Lyman x-ray emission following electron capture and K excitation has been studied in collisions of bare and Li-like sulphur ions (of energy 110 MeV) with fullerenes (C(60)/C(70)) and different gaseous targets. The intensity ratios of different Lyman x-ray lines in collisions with fullerenes are found to be substantially lower than those for the gas targets, both for capture and excitation. This has been explained in terms of a model based on "solidlike" effect, namely, wakefield induced stark mixing of the excited states populated via electron capture or K excitation: a collective phenomenon of plasmon excitation in the fullerenes under the influence of heavy, highly charged ions.

  8. Electron-capture ratios in radio-active decay

    International Nuclear Information System (INIS)

    Pelt, J. van.

    1978-01-01

    A review of the theory of electron capture is given and expressions for the electron-capture ratios derived. Attention is paid to the calculations of exchange and overlap correction factors. The theoretical results are then compared with experimental values on the basis of two recently published compilations. The experimental set-up used in this investigation is described and the analysis of the scintillation spectra discussed. Measurements on 131 Ba, 106 Agsup(m) and 196 Au are described and values derived for the exchange and overlap corrections and for the atomic electron-capture transition energy Qsub(EC). (Auth.)

  9. Identification and systematical studies of the electron-capture delayed fission (ECDF) in the lead region

    CERN Multimedia

    Pauwels, D B; Lane, J

    2008-01-01

    In our recent experiment (March 2007) at the velocity filter SHIP(GSI) we observed the electron-capture delayed fission of the odd-odd isotope $^{194}$At. This is the first unambiguous identification of this phenomenon in the very neutron-deficient nuclei in the vicinity of the proton shell closure at Z=82. In addition, the total kinetic energy (TKE) for the daughter nuclide $^{194}$Po was measured, despite the fact that this isotope does not decay via spontaneous fission. Semi-empirical analysis of the electron-capture Q$_{EC}$ values and fission barriers B$_{f}$ shows that a relatively broad island of ECDF must exist in this region of the Nuclide Chart, with some of the nuclei having unusually high ECDF probabilities. Therefore, this Proposal is intended to initiate the systematic identification and study of $\\beta$-delayed fission at ISOLDE in the very neutron-deficient lead region. Our aim is to provide unique low-energy fission data (e.g. probabilities, TKE release, fission barriers and their isospin dep...

  10. Isomer depletion as experimental evidence of nuclear excitation by electron capture

    Science.gov (United States)

    Chiara, C. J.; Carroll, J. J.; Carpenter, M. P.; Greene, J. P.; Hartley, D. J.; Janssens, R. V. F.; Lane, G. J.; Marsh, J. C.; Matters, D. A.; Polasik, M.; Rzadkiewicz, J.; Seweryniak, D.; Zhu, S.; Bottoni, S.; Hayes, A. B.; Karamian, S. A.

    2018-02-01

    The atomic nucleus and its electrons are often thought of as independent systems that are held together in the atom by their mutual attraction. Their interaction, however, leads to other important effects, such as providing an additional decay mode for excited nuclear states, whereby the nucleus releases energy by ejecting an atomic electron instead of by emitting a γ-ray. This ‘internal conversion’ has been known for about a hundred years and can be used to study nuclei and their interaction with their electrons. In the inverse process—nuclear excitation by electron capture (NEEC)—a free electron is captured into an atomic vacancy and can excite the nucleus to a higher-energy state, provided that the kinetic energy of the free electron plus the magnitude of its binding energy once captured matches the nuclear energy difference between the two states. NEEC was predicted in 1976 and has not hitherto been observed. Here we report evidence of NEEC in molybdenum-93 and determine the probability and cross-section for the process in a beam-based experimental scenario. Our results provide a standard for the assessment of theoretical models relevant to NEEC, which predict cross-sections that span many orders of magnitude. The greatest practical effect of the NEEC process may be on the survival of nuclei in stellar environments, in which it could excite isomers (that is, long-lived nuclear states) to shorter-lived states. Such excitations may reduce the abundance of the isotope after its production. This is an example of ‘isomer depletion’, which has been investigated previously through other reactions, but is used here to obtain evidence for NEEC.

  11. Exact capture probability analysis of GSC receivers over i.n.d. Rayleigh fading channels

    KAUST Repository

    Nam, Sungsik

    2013-07-01

    A closed-form expression of the capture probability of generalized selection combining (GSC) RAKE receivers was introduced in [1]. The idea behind this new performance metric is to quantify how the remaining set of uncombined paths affects the overall performance both in terms of loss in power and increase in interference levels. In this previous work, the assumption was made that the fading is both independent and identically distributed from path to path. However, the average strength of each path is different in reality. In order to derive a closed-form expression of the capture probability over independent and non-identically distributed (i.n.d.) fading channels, we need to derive the joint statistics of ordered non-identical exponential variates. With this motivation in mind, we first provide in this paper some new order statistics results in terms of both moment generating function (MGF) and probability density function (PDF) expressions under an i.n.d. assumption and then derive a new exact closed-form expression for the capture probability GSC RAKE receivers in this more realistic scenario. © 2013 IEEE.

  12. Role of projectile anti K-electrons in single and double K to anti K transfer: Comparison of passive anti K-electron models and of the IFPM with data for Cl17+,16+,≤14+ + Ti

    International Nuclear Information System (INIS)

    Becker, R.L.

    1987-01-01

    Electron transfer between a neutral target and a projectile ion is one of the more interesting and difficult processes to calculate. Experimentally, there is no simple, yet clean, way to measure transfer from a given shell to a given shell. For the case of K to anti K transfer (the bar designating the projectile) an indirect method is common. One measures K-vacancy cross sections for projectiles with ionic charges q=Z, Z-1, and ≤(Z-2). Then with the assumption that the initial anti K electrons are inert, one infers the K 1 to anti K 1 and K 2 to anti K 2 cross sections from linear combinations of the measured cross sections. The postulate that anti K-electrons are inert is brought into doubt by noting that the probability of inverse (anti K to K) transfer is equal by time-reversal invariance to that for K to anti K transfer. An extensive set of such measurements has been reported recently by Hall et al. for the nearly symmetric, strongly interacting systems 17 Cl q+ + 22 Ti. We have performed coupled-channels calculations for these systems and have compared results of various forms of the independent Fermi particle model (IFPM) with and without the assumption that any initially present anti K electron is passive. The passive anti K-electron models provide only a fair approximation to the results of the full IFPM. (orig.)

  13. Capturing alternative secondary structures of RNA by decomposition of base-pairing probabilities.

    Science.gov (United States)

    Hagio, Taichi; Sakuraba, Shun; Iwakiri, Junichi; Mori, Ryota; Asai, Kiyoshi

    2018-02-19

    It is known that functional RNAs often switch their functions by forming different secondary structures. Popular tools for RNA secondary structures prediction, however, predict the single 'best' structures, and do not produce alternative structures. There are bioinformatics tools to predict suboptimal structures, but it is difficult to detect which alternative secondary structures are essential. We proposed a new computational method to detect essential alternative secondary structures from RNA sequences by decomposing the base-pairing probability matrix. The decomposition is calculated by a newly implemented software tool, RintW, which efficiently computes the base-pairing probability distributions over the Hamming distance from arbitrary reference secondary structures. The proposed approach has been demonstrated on ROSE element RNA thermometer sequence and Lysine RNA ribo-switch, showing that the proposed approach captures conformational changes in secondary structures. We have shown that alternative secondary structures are captured by decomposing base-paring probabilities over Hamming distance. Source code is available from http://www.ncRNA.org/RintW .

  14. Neutrinoless double electron capture decay of 54-Fe

    International Nuclear Information System (INIS)

    Bikit, I; Krmar, M.; Slivka, J.; Anicin, I.; Veskovic, M.; Convie, L.

    1994-01-01

    Double electron capture is the only decay mode of 54-Fe to 54-Cr. The most probable KK capture in the 0 nu case would lead to an otherwise not populated excited state of 54-Cr with the energy of 668 + - KeV. This process has not been yet investigated, probably because the lacking theoretical arguments on the nature of the excited state which could favour the decay. On the other hand if we suppose that gamma transition from this state to the ground state is allowed the 668 KeV gamma ray would be a definite signature of the process. Having in mind the relatively large abundance of 54-Fe in natural iron, a large quantity of iron in some shields in low level gamma spectroscopy systems and the low and flat background in the 668 keV spectral region, we easily estimate that the sensitivity for measuring the half life of this process is quit high. With our equipment consisting of a 25% efficiency commercial HP Ge spectrometer, placed in a cubic shaped iron shield with wall thickness of 25 cm from the background spectrum measured for only 100 days we calculated the lower limit for the half life of the 0 nu EC.EC decay of 54-Fe on the 68% confidence level to be T > 3.1 *10 sup 2 sup 2 years. 2 figs., 5 refs. (author)

  15. On Z-dependence of probability of atomic capture of mesons in matter

    International Nuclear Information System (INIS)

    Vasil'ev, V.A.; Petrukhin, V.I.; Suvorov, V.M.; Khorvat, D.

    1976-01-01

    All experimental data available on the atomic capture of negative muons and pions are systematically studied to find more appropriate empirical expression for the capture probability as a function of the atomic number. It is shown that Z-dependence, as a rule, does not hold. Zsup(1/3)-dependence gives more satisfactory results. A modified Zsup(1/3-dependence is proposed which is more appropriate for hydrogen - containing compounds

  16. Negative meson capture in hydrogen

    International Nuclear Information System (INIS)

    Baird, T.J.

    1977-01-01

    The processes of deexcitation and capture of negative mesons and hadrons in atomic hydrogen are investigated. Only slow collisions in which the projectile-atom relative velocity is less than one atomic unit are considered, and the motion of the incident particle is treated classically. For each classical trajectory the probability of ionizing the hydrogen atom is determined, together with the energy spectrum of the emitted electron. Ionization probabilities are calculated using the time-dependent formulation of the perturbed stationary state method. Exact two-center electronic wave functions are used for both bound and continuum states. The total ionization cross section and electron energy spectrum have been calculated for negative muons, kaons and antiprotons at incident relative velocities between 0.04 and 1.0 atomic units. The electron energy spectrum has a sharp peak for electron kinetic energies on the order of 10 -3 Rydbergs. The ionization process thus favors the emission of very slow electrons. The cross section for ionization with capture of the incident particle was calculated for relative kinetic energies greater than 1.0 Rydberg. Since ionization was found to occur with the emission of electrons of nearly zero kinetic energy, the fraction of ionizing collisions which result in capture decreases very rapidly with projectile kinetic energy. The energy distributions of slowed down muons and hadrons were also computed. These distributions were used together with the capture cross section to determine the distribution of kinetic energies at which capture takes place. It was found that most captures occur for kinetic energies slightly less than 1.0 Rydbergs with relatively little capture at thermal energies. The captured particles therefore tend to go into very large and loosely found orbits with binding energies less than 0.1 Rydbergs

  17. Radiative electron capture for F8+ and F9+ ions in collisions with a He gas target

    International Nuclear Information System (INIS)

    Kawatsura, K.; Richard, P.; Tawara, H.

    1981-01-01

    The x rays from the radiative electron capture (REC) to the projectile K-shell were investigated for F 8+ and F 9+ ions incident on the He target atoms in the projectile energy range from 15 to 40 MeV. The peak energies of the K-REC x-ray spectra were found to decrease linearly with a decrease of the projectile energies as expected and extrapolated to the correct ls binding energies at zero velocity. According to theory the distribution width of the REC energies should be independent of the binding energy of electrons in the projectile ions. However, it is found that this width for F 8+ ions is systematically smaller by 20% than that for F 9+ ions. The measured REC cross sections for F 9+ ions are slightly larger than twice those for F 8+ ions and the total REC cross sections for F 8+ and F 9+ ions were found to be more than three orders of magnitude smaller than the total electron capture cross sections and the capture cross sections into excited states

  18. Selection of the optimum condition for electron capture detector operation

    International Nuclear Information System (INIS)

    Lasa, J.; Korus, A.

    1974-01-01

    A method of determination of the optimal work conditions for the electron capture detector is presented in the paper. Physical phenomena which occur in the detector, as well as the energetic dependence of the electron attachment process are taken into consideration. The influence of the kind of carrier gas, temperature, and the parameters of the supplied voltage in both direct and pulse methods on average values of electron energy is described. Dependence of the sensitivity of the electron capture detector on the carrier gas and the polarizing voltage is illustrated for the Model DNW-300 electron capture detector produced in Poland. Practical indications for selecting optimal conditions of electron capture detector operation are given at the end of the paper. (author)

  19. Electron capture in proton collisions with alkali atoms as a three-body problem

    International Nuclear Information System (INIS)

    Avakov, G.V.; Blokhintsev, L.D.; Kadyrov, A.S.; Mukhamedzhanov, A.M.

    1992-01-01

    A previous paper proposed an approach to the calculation of electron transfer reactions in ion-atomic collisions based on the Faddeev three-body equations written in the Alt-Grassberger-Sandhas form. In the present work this approach is used to describe the electron capture in proton collisions with alkali atoms. The results of calculation of the total and partial cross sections for charge exchange in proton collisions with Li, Na, K and Rb atoms are presented. The calculated total cross sections are in good agreement with experiment for light target atoms. In going over to heavier targets, the theoretical total cross sections, while agreeing in form, tend to be larger than the experimental ones. The calculated partial cross sections for electron capture into the 2s state of the H atom are also in agreement with experiment. Some other partial cross sections were also calculated. (author)

  20. The mass of the electron neutrino and electron capture in 163Ho

    International Nuclear Information System (INIS)

    Yasumi, S.; Rajasekaran, G.; Ando, M.; Ochiai, F.; Ikeda, H.; Ohta, T.; Stefan, P.M.; Maruyama, M.; Nashimoto, N.; Fujioka, M.; Ishii, K.; Shinozuka, T.; Sera, K.; Omori, T.; Izawa, G.; Yagi, M.; Masumoto, K.; Shima, K.

    1983-01-01

    To determine the mass of the electron neutrino, electron capture in 163 Ho was studied. From the intensity of M X-rays and the total number of 163 Ho atoms in a source, as determined by the PIXE method, the partial M-capture half life of 163 Ho was estimated to be (4.5 +- 1.5) x 10 4 yr. A relation between the Q-value of 163 Ho and the mass of the electron neutrino was obtained. (orig.)

  1. K-shell ionization probability in energetic nearly symmetric heavy-ion collisions

    International Nuclear Information System (INIS)

    Tserruya, I.; Schmidt-Boecking, H.; Schuch, R.

    1977-01-01

    Impact parameter dependent K-x-ray emission probabilities for the projectile and target atoms have been measured in 35 MeV Cl on Cl, Cl on Ti and Cl on Ni collisions. The sum of projectile plus target K-shell ionization probability is taken as a measure of the total 2psigma ionization probability. The 2pπ-2psigma totational coupling model is in clear disagreement with the present results. On the other hand the sum of probabilities is reproduced both in shape and absolute magnitude by the statistical model for inner-shell ionization. The K-shell ionization probability of the higher -Z collision partner is well described by this model including the 2psigma-1ssigma vacancy sharing probability calculated as a function of the impact parameter. (author)

  2. Radiative electron capture studied in relativistic heavy-ion--atom collisions

    International Nuclear Information System (INIS)

    Stoehlker, T.; Kozhuharov, C.; Mokler, P.H.; Warczak, A.; Bosch, F.; Geissel, H.; Moshammer, R.; Scheidenberger, C.; Eichler, J.; Ichihara, A.; Shirai, T.; Stachura, Z.; Rymuza, P.

    1995-01-01

    The process of radiative electron capture (REC) in relativistic collisions of high-Z ions with low-Z gaseous and solid targets is studied experimentally and theoretically. The observed x-ray spectra are analyzed with respect to photon angular distributions as well as to total K-REC cross sections. The experimental results for angle-differential cross sections are well reproduced by exact relativistic calculations which yield significant deviations from standard sin 2 θ distributions. Total cross sections for K-REC are shown to follow a simple scaling rule obtained from exact relativistic calculations as well as from a nonrelativistic dipole approximation. The agreement between these different theoretical approaches must be regarded as fortuitous, but it lends support to the use of the nonrelativistic approach for practical purposes

  3. Electron-capture process and ion mobility spectra in plasma chromatography

    International Nuclear Information System (INIS)

    Karasek, F.W.; Spangler, G.E.

    1981-01-01

    The basic principles of plasma chromatography are introduced and ion mobility relationships presented. The relationships of plasma chromatography to electron-capture detector mechanisms are discussed, including electron energy considerations and electron-capture reactions. A number of experimental studies by plasma chromatography are described. (C.F.)

  4. Estimating the population size and colony boundary of subterranean termites by using the density functions of directionally averaged capture probability.

    Science.gov (United States)

    Su, Nan-Yao; Lee, Sang-Hee

    2008-04-01

    Marked termites were released in a linear-connected foraging arena, and the spatial heterogeneity of their capture probabilities was averaged for both directions at distance r from release point to obtain a symmetrical distribution, from which the density function of directionally averaged capture probability P(x) was derived. We hypothesized that as marked termites move into the population and given sufficient time, the directionally averaged capture probability may reach an equilibrium P(e) over the distance r and thus satisfy the equal mixing assumption of the mark-recapture protocol. The equilibrium capture probability P(e) was used to estimate the population size N. The hypothesis was tested in a 50-m extended foraging arena to simulate the distance factor of field colonies of subterranean termites. Over the 42-d test period, the density functions of directionally averaged capture probability P(x) exhibited four phases: exponential decline phase, linear decline phase, equilibrium phase, and postequilibrium phase. The equilibrium capture probability P(e), derived as the intercept of the linear regression during the equilibrium phase, correctly projected N estimates that were not significantly different from the known number of workers in the arena. Because the area beneath the probability density function is a constant (50% in this study), preequilibrium regression parameters and P(e) were used to estimate the population boundary distance 1, which is the distance between the release point and the boundary beyond which the population is absent.

  5. Correlated electron capture and inner-shell excitation measurements in ion-atom collisions

    International Nuclear Information System (INIS)

    Tanis, J.A.; Bernstein, E.M.; Clark, M.W.

    1985-01-01

    In an ion-atom collision projectile excitation and charge transfer (electron capture) may occur together in a single encounter. If the excitation and capture are correlated, then the process is called resonant transfer and excitation (RTE); if they are uncorrelated, then the process is termed nonresonant transfer and excitation (NTE). Experimental work to date has shown the existence of RTE and provided strong evidence for NTE. Results presented here provide information on the relative magnitudes of RTE and NTE, the charge state dependence of RTE, the effect of the target momentum distribution on RTE, the magnitude of L-shell RTE compared to K-shell RTE, and the target Z dependences of RTE and NTE. 15 refs., 5 figs

  6. Elastic K-means using posterior probability.

    Science.gov (United States)

    Zheng, Aihua; Jiang, Bo; Li, Yan; Zhang, Xuehan; Ding, Chris

    2017-01-01

    The widely used K-means clustering is a hard clustering algorithm. Here we propose a Elastic K-means clustering model (EKM) using posterior probability with soft capability where each data point can belong to multiple clusters fractionally and show the benefit of proposed Elastic K-means. Furthermore, in many applications, besides vector attributes information, pairwise relations (graph information) are also available. Thus we integrate EKM with Normalized Cut graph clustering into a single clustering formulation. Finally, we provide several useful matrix inequalities which are useful for matrix formulations of learning models. Based on these results, we prove the correctness and the convergence of EKM algorithms. Experimental results on six benchmark datasets demonstrate the effectiveness of proposed EKM and its integrated model.

  7. State selective single-electron capture in O6++Nacollisions

    NARCIS (Netherlands)

    Knoop, S; Keim, M; Ludde, HJ; Kirchner, T; Morgenstern, [No Value; Hoekstra, R

    2005-01-01

    Single-electron capture in O6+ + Na collisions at 1-9 keV/amu collision energy has been studied both experimentally and theoretically. Partial cross sections for electron capture into n = 5, 6, 7, 8 and n >= 9 have been obtained from target recoil momenta measured by the technique of MOTRIMS and are

  8. Total K-vacancy production in Ne (10 MeV) traversing Al

    International Nuclear Information System (INIS)

    Groeneveld, K.O.; Kolb, B.; Schader, J.; Sevier, K.D.

    1976-01-01

    Deexcitation of projectile inner shell vacancies created while traversing a solid foil may take place via competing processes: a) vacancy sharing with foil atoms in close impacts, b) radiative and non-radiative electron capture, and c) such X-ray and Auger electron transitions are possible in the heavy ion projectile. The change in K-vacancy creation with foil thickness can be investigated by measuring either projectile or target X-rays where the vacancies are created by Coulomb excitation and process a. In the system Ne (10 MeV) on Al, detecting Al K X-rays, the Ne K-vacancy production probability has been determined. (orig.) [de

  9. Three L-subshells atomic model to compute counting efficiency of electron-capture nuclides; Modelo con tres subcapas L para calcular la eficiencia de recuento de nucleidos que se desintegran por captura electronica

    Energy Technology Data Exchange (ETDEWEB)

    Grau, A.; Arcos, J. M. los

    1986-07-01

    The present paper develops a three L-subshell a and K, M-a hells atomic model in order to obtain the counting efficiency in liquid scintillation counting. Mathematical expressions are given to calculate the probabilities of 264 different atomic rearrangement way so as the corresponding effective energies. This new model will permit to test the influence of the different atomic and nuclear parameters upon the counting efficiency nuclides of low and medium atomic number decaying by electron capture. (Author) 8 refs.

  10. Electron capture detector based on a non-radioactive electron source: operating parameters vs. analytical performance

    Directory of Open Access Journals (Sweden)

    E. Bunert

    2017-12-01

    Full Text Available Gas chromatographs with electron capture detectors are widely used for the analysis of electron affine substances such as pesticides or chlorofluorocarbons. With detection limits in the low pptv range, electron capture detectors are the most sensitive detectors available for such compounds. Based on their operating principle, they require free electrons at atmospheric pressure, which are usually generated by a β− decay. However, the use of radioactive materials leads to regulatory restrictions regarding purchase, operation, and disposal. Here, we present a novel electron capture detector based on a non-radioactive electron source that shows similar detection limits compared to radioactive detectors but that is not subject to these limitations and offers further advantages such as adjustable electron densities and energies. In this work we show first experimental results using 1,1,2-trichloroethane and sevoflurane, and investigate the effect of several operating parameters on the analytical performance of this new non-radioactive electron capture detector (ECD.

  11. Radiative electron capture studied in relativistic heavy-ion atom collisions

    International Nuclear Information System (INIS)

    Stoehlker, T.; Kozhuharov, C.; Mokler, P.H.; Warczak, A.; Bosch, F.; Geissel, H.; Moshammer, R.; Scheidenberger, C.; Eichler, J.; Shirai, T.; Stachura, Z.; Rymuza, P.

    1994-08-01

    The process of Radiative Electron Capture (REC) in relativistic collisions of high-Z ions with low-Z gaseous and solid targets is studied experimentally and theoretically. The observed X-ray spectra are analysed with respect to photon angular distributions as well as to total K-REC cross sections. The experimental results for angle-differential cross sections are well-reproduced by exact relativistic calculations which yield significant deviations from standard sin 2 θ distributions. Total cross sections for K-REC are shown to follow a simple scaling rule obtained from exact relativistic calculations as well as from a non-relativistic dipole approximation. The agreement between these different theoretical approaches must be regarded as fortuitous, but it lends support to the use of the non-relativistic approach for practical purposes. (orig.)

  12. Electron capture and transfer-ionization processes in {sup 4}He{sup 2+}+Ar collision at 12.5 keV amu{sup -1}

    Energy Technology Data Exchange (ETDEWEB)

    Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A.; Benhenni, M. [Laboratoire Collisions, Agregats, Reactivite, IRSAMC, UMR 5589 CNRS and Universite Paul Sabatier, 31062 Toulouse Cedex (France)

    1998-05-14

    Electron emission in the {sup 4}He{sup 2+}+Ar collisional system has been investigated at 35 deg. and 12.5 keV amu{sup -1} collision velocity, in coincidence with the recoil target ion charges. Direct single ionization is found to be negligible with respect to single-electron capture. Contributions of transfer-ionization processes are stressed in the production of Ar{sup 2+} to Ar{sup 4+} ions; those of direct ionization, double excitation of the target and double capture into autoionization states of helium are instead found to be much less probable. Among the two-electron processes which explain the formation of Ar{sup 2+} ions, the double capture into autoionizing states of helium remains unimportant with respect to a pure transfer ionization process (one captured electron plus one ionized electron). The measured predominant production of Ar{sup 3+} ions illustrates the role played by three-electron processes, mainly a two-electron transfer accompanied by a single-target ionization. Finally, the formation of Ar{sup 4+} ions is connected with more complex transfer ionization processes. A qualitative analysis of these results is made within the quasimolecular approach. (author). Letter-to-the-editor.

  13. Electronic case report forms and electronic data capture within clinical trials and pharmacoepidemiology.

    Science.gov (United States)

    Rorie, David A; Flynn, Robert W V; Grieve, Kerr; Doney, Alexander; Mackenzie, Isla; MacDonald, Thomas M; Rogers, Amy

    2017-09-01

    Researchers in clinical and pharmacoepidemiology fields have adopted information technology (IT) and electronic data capture, but these remain underused despite the benefits. This review discusses electronic case report forms and electronic data capture, specifically within pharmacoepidemiology and clinical research. The review used PubMed and the Institute of Electrical and Electronic Engineers library. Search terms used were agreed by the authors and documented. PubMed is medical and health based, whereas Institute of Electrical and Electronic Engineers is technology based. The review focuses on electronic case report forms and electronic data capture, but briefly considers other relevant topics; consent, ethics and security. There were 1126 papers found using the search terms. Manual filtering and reviewing of abstracts further condensed this number to 136 relevant manuscripts. The papers were further categorized: 17 contained study data; 40 observational data; 27 anecdotal data; 47 covering methodology or design of systems; one case study; one literature review; two feasibility studies; and one cost analysis. Electronic case report forms, electronic data capture and IT in general are viewed with enthusiasm and are seen as a cost-effective means of improving research efficiency, educating participants and improving trial recruitment, provided concerns about how data will be protected from misuse can be addressed. Clear operational guidelines and best practises are key for healthcare providers, and researchers adopting IT, and further work is needed on improving integration of new technologies with current systems. A robust method of evaluation for technical innovation is required. © 2017 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.

  14. Exact capture probability analysis of GSC receivers over Rayleigh fading channel

    KAUST Repository

    Nam, Sungsik

    2010-01-01

    For third generation systems and ultrawideband systems, RAKE receivers have been introduced due to the advantage of RAKE receivers which is their ability to combine different replicas of the transmitted signal arriving at different delays in a rich multipath environment. In principle, RAKE receivers combine all resolvable paths which gives the best performance in a rich diversity environment. However, this is usually costly in terms of hardware required as the number of RAKE fingers increases. Therefore, generalized selection combining (GSC) RAKE reception was proposed and has been studied by many researcher as an alternative to the classical two fundamental diversity schemes: maximal ratio combining and selection combining. Previous work on performance analyses of GSC RAKE receivers based on the signal to noise ratio focused on the development of methodologies to derive exact closedform expressions for various performance measures. However, the remaining set of uncombined paths affect the overall performance both in terms of loss in power. Therefore, to have a full understanding of the performance of GSC RAKE receivers, we introduce in this paper the notion of capture probability, which is defined as the ratio of the captured power (essentially combined paths power) to that of the total available power. The major difficulty in these problems is to derive some joint statistics of ordered exponential variates. With this motivation in mind, we capitalize in this paper on some new order statistics results to derive exact closed-form expressions for the capture probability over independent and identically distributed Rayleigh fading channels. © 2010 IEEE.

  15. Single electron capture in N^+ -(Ne, Kr, Xe) collisions

    Science.gov (United States)

    Reyes, Pedro G.; Castillo, Fermin; Martinez, Horacio

    2001-05-01

    Total cross sections for single electron capture of N^+ ions impinging on Ne, Kr and Xe were measured in the energy range of 1.5 to 5.0 keV. The electron capture cross sections for all the targets studied are found to be in excellent agreement with previous data in the low-energy range. The present data together with previous measurements give a general shape of the whole curve of single electron capture cross sections for the N^+ - Ne system. For the cases of N^+ - (Kr, Xe) systems, semiempirical calculation using the two-state approximation are in very good agreement with present cross sections data. Research supported by DGAPA IN-100392 and CONACyT 32175-E

  16. Evidence for correlated double-electron capture in slow O6+ + He collisions

    International Nuclear Information System (INIS)

    Phaneuf, R.A.; Meyer, F.W.; Havener, C.C.; Stolterfoht, N.; Swenson, J.K.; Shafroth, S.M.

    1987-01-01

    Double electron capture by few-electron multicharged ions during slow collisions with He may result in Auger-decaying product states of the projectile, provided the initial projectile charge exceeds +4. These autoionizing states can be characterized by either (nearly) equivalent electron configurations, in which the two captured electrons occupy essentially the same or adjacent shells, or by non-equivalent configurations, in which one of the electrons is in a Rydberg state. Using the method of zero-degree Auger spectroscopy, the authors have verified population of both types of autoionizing states by double electron capture during slow collisions of O 6+ with He: for these systems, both LMM Auger electrons, attributed to the (nearly) equivalent electron configuration (1s 2 ) 3iota3iota' or (1s 2 )3iota4iota', and L 1 L 23 M-Coster Kronig electrons, attributed to the non-equivalent electron configurations (1s 2 )2pniota, were observed. Comparison of the LMM Auger electron and Coster Kronig electron production cross sections suggests that the correlated double capture process is of comparable importance to the sequential single capture mechanism

  17. Electron capture to autoionizing states of multiply charged ions

    International Nuclear Information System (INIS)

    Mack, E.M.

    1987-01-01

    The present thesis investigates electron capture reactions resulting from slow collisions (V q+ ) and neutral gas targets (B). The energy spectra of the emitted electrons are measured; detection angle is 50 0 . Mainly, autoionizing double capture resulting from collisions with two-electron targets (He, H 2 ) is studied; then, the emitted electrons stem from doubly excited projectile states. The projectiles used are bare C 6+ , the H-like and He-like ions of C, N and O, He-like Ne 8+ and Ne-like Ar 8+ . Excited metastable projectiles used are C 5+ (2s), He-like projectiles A q+ (1s2s 3 S) and Ar 8+ (...2p 5 3s). Comparison is made with the predictions of a recently proposed extended classical barrier model, that was developed in connection with the work. This model assumes sequential capture of the electrons ('two-step' process); it predicts the realized binding enegies of the captured electrons - which may be directly determined from the autoionization spectra using only the projectile charge, the ionization potentials of the target and the collision velocity as parameters. No adjustable parameter enters into the calculations. The term energies and decay modes of the highly excited product ions themselves are studied. Generally, the autoionizing decay of these states is found to proceed preferentially to the directly adjacent lower singly excited state. Experimental evidence is presented, that triply excited states decay by successive emission of two electrons, whenever this is energetically possible. Finally, the L-MM decay in few-electron systems is considered. 314 refs.; 96 figs.; 29 tabs

  18. Physics Reach with a Monochromatic Neutrino Beam from Electron Capture

    CERN Document Server

    Bernabeu, J.; Espinoza, C.; Lindroos, M.

    2005-01-01

    Neutrino oscillation experiments from different sources have demonstrated non-vanishing neutrino masses and flavour mixings. The next experiments have to address the determination of the connecting mixing U(e3) and the existence of the CP violating phase. Whereas U(e3) measures the strength of the oscillation probability in appearance experiments, the CP phase acts as a phase-shift in the interference pattern. Here we propose to separate these two parameters by energy dependence, using the novel idea of a monochromatic neutrino beam facility based on the acceleration of ions that decay fast through electron capture. Fine tuning of the boosted neutrino energy allows precision measurements able to open a window for the discovery of CP violation, even for a mixing as small as 1 degree

  19. Precision electron-capture energy in {sup 202}Pb and its relevance for neutrino mass determination

    Energy Technology Data Exchange (ETDEWEB)

    Welker, A. [CERN, Geneva (Switzerland); Technische Universitaet Dresden, Dresden (Germany); Filianin, P. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Althubiti, N.A.S. [The University of Manchester, School of Physics and Astronomy, Manchester (United Kingdom); Atanasov, D.; Blaum, K.; Eliseev, S.; Kreim, S. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Cocolios, T.E. [The University of Manchester, School of Physics and Astronomy, Manchester (United Kingdom); KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Herfurth, F.; Neidherr, D. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Lunney, D. [CSNSM-IN2P3-CNRS, Universite Paris-Sud, Orsay (France); Manea, V. [CERN, Geneva (Switzerland); Novikov, Yu. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Physics Faculty, St. Petersburg State University (Russian Federation); Rosenbusch, M.; Schweikhard, L.; Wienholtz, F. [Ernst-Moritz-Arndt-Universitaet, Institut fuer Physik, Greifswald (Germany); Wolf, R.N. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); The University of Sydney, ARC Centre of Excellence for Engineered Quantum Systems, Sydney (Australia); Zuber, K. [Technische Universitaet Dresden, Dresden (Germany)

    2017-07-15

    Within the framework of an extensive programme devoted to the search for alternative candidates for the neutrino mass determination, the atomic mass difference between {sup 202}Pb and {sup 202}Tl has been measured with the Penning trap mass spectrometer ISOLTRAP at the ISOLDE facility at CERN. The obtained value Q{sub EC} = 38.8(43) keV is three times more precise than the AME2012 value. While it will probably not lead to a replacement of {sup 163}Ho in modern experiments on the determination of the electron-neutrino mass, the electron capture in {sup 202}Pb would however allow a determination of the electron-neutrino mass on the few-eV level using a cryogenic micro-calorimeter. (orig.)

  20. Correlated electron capture in the impact parameter and final projectile charge-state dependence of ECC cusp production in 0.53 MeV u-1 F8+ + Ne

    International Nuclear Information System (INIS)

    Skutlartz, A.; Hagmann, S.; Schmidt-Boecking, H.

    1988-01-01

    The impact parameter dependence of ECC cusp electron production in collisions of fast, highly charged ions with atoms is investigated by measuring the scattered projectiles in coincidence with cusp electrons emitted at 0 0 with respect to the beam axis. The absolute probabilities for ECC cusp production show a maximum at b ≅ 0.10 au, decrease strongly for smaller impact parameters and more gently toward larger impact parameters. In addition the final charge state of the scattered projectile is also determined simultaneously for each collision event. The probabilities, as a function of the projectile final charge state, are large for the case where at least one or more electrons are simultaneously captured into bound states of the projectile, but are surprisingly small for collisions in which a projectile did not capture an electron into a bound state. (author)

  1. Maximum entropy theory of recoil charge distributions in electron-capture collisions

    International Nuclear Information System (INIS)

    Aberg, T.; Blomberg, A.; Tulkki, J.; Goscinski, O.

    1984-01-01

    A generalized Fermi-Dirac distribution is derived and applied to charge-state distributions in single collisions between multiply charged ions and rare-gas atoms. It relates multiple electron loss in single-electron capture to multiple ionization in multiphoton absorption and discloses inner-shell vacancy formation in double- and triple-electron capture

  2. Supernovae and nuclear structure: Electron capture and the nuclear incompressibility

    International Nuclear Information System (INIS)

    Cooperstein, J.

    1985-01-01

    The author considers the effects of electron capture and the high density equation of state on supernovae. Electron captures on nuclei with 60 s it is helpful for supernovae to have a soft equation of state. Present knowledge of the nuclear matter parameters is considered and implications for supernovae are drawn. (orig.)

  3. Enhanced electron capture by fast heavy di-clusters exciting solids

    International Nuclear Information System (INIS)

    Cooney, P.J.; Faibis, A.; Kanter, E.P.; Koenig, W.; Maor, D.; Zabransky, B.J.

    1985-01-01

    The authors have studied the dependence of the charge-state-distributions of heavy-ion fragments resulting from the foil-induced dissociation of 4.2-MeV N 2 + ions on the thickness of the carbon target foil. The results were compared to those distributions measured for impact of 2.1-MeV N + projectiles. Whereas the charge-state distributions for atomic ion impact are already equilibrated in the thinnest targets used (2 μg/cm 2 ), those measured for molecular ion impact are strongly dependent on the target thickness, even for the thickest targets (100 + g/cm 2 ). The distributions for molecular-ion impact show a marked shift towards lower charge states, evidencing an enhanced electron capture probability over the case of monatomic ion impact. A quantitative model was developed to explain this phenomenon

  4. The boundary-corrected second Born (B2B) approximation: proton-hydrogen electron capture

    International Nuclear Information System (INIS)

    Dewangan, D.P.; Bransden, B.H.

    1988-01-01

    The probability amplitude for proton-hydrogen ground-state electron capture at 125 keV in the boundary-corrected second Born approximation has been evaluated numerically by retaining all significant bound and continuum hydrogenic intermediate states for which the orbital angular momentum l ≤ 3. The differential cross section is found to be in good agreement with the experimental data for scattering angles less than about 1 mrad in the centre of mass system. The value of the boundary-corrected second Born total cross section is similar to that obtained in the boundary-corrected first Born approximation. (author)

  5. Ultralow energy calibration of LUX detector using Xe 127 electron capture

    Science.gov (United States)

    Akerib, D. S.; Alsum, S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Brás, P.; Byram, D.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; Dobi, A.; Druszkiewicz, E.; Edwards, B. N.; Fallon, S. R.; Fan, A.; Fiorucci, S.; Gaitskell, R. J.; Genovesi, J.; Ghag, C.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Jacobsen, R. G.; Ji, W.; Kamdin, K.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Manalaysay, A.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O'Sullivan, K.; Oliver-Mallory, K. C.; Palladino, K. J.; Pease, E. K.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Solmaz, M.; Solovov, V. N.; Sorensen, P.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W. C.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Velan, V.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Xu, J.; Yazdani, K.; Young, S. K.; Zhang, C.

    2017-12-01

    We report an absolute calibration of the ionization yields (Qy ) and fluctuations for electronic recoil events in liquid xenon at discrete energies between 186 eV and 33.2 keV. The average electric field applied across the liquid xenon target is 180 V /cm . The data are obtained using low energy Xe 127 electron capture decay events from the 95.0-day first run from LUX (WS2013) in search of weakly interacting massive particles. The sequence of gamma-ray and x-ray cascades associated with I 127 deexcitations produces clearly identified two-vertex events in the LUX detector. We observe the K-(binding energy, 33.2 keV), L-(5.2 keV), M-(1.1 keV), and N-(186 eV) shell cascade events and verify that the relative ratio of observed events for each shell agrees with calculations. The N-shell cascade analysis includes single extracted electron (SE) events and represents the lowest-energy electronic recoil in situ measurements that have been explored in liquid xenon.

  6. Search for neutrinoless double-electron capture of 156Dy

    Science.gov (United States)

    Finch, S. W.; Tornow, W.

    2015-12-01

    Background: Multiple large collaborations are currently searching for neutrinoless double-β decay, with the ultimate goal of differentiating the Majorana-Dirac nature of the neutrino. Purpose: Investigate the feasibility of resonant neutrinoless double-electron capture, an experimental alternative to neutrinoless double-β decay. Method: Two clover germanium detectors were operated underground in coincidence to search for the de-excitation γ rays of 156Gd following the neutrinoless double-electron capture of 156Dy. 231.95 d of data were collected at the Kimballton underground research facility with a 231.57 mg enriched 156Dy sample. Results: No counts were seen above background and half-life limits are set at O (1016-1018) yr for the various decay modes of 156Dy. Conclusion: Low background spectra were efficiently collected in the search for neutrinoless double-electron capture of 156Dy, although the low natural abundance and associated lack of large quantities of enriched samples hinders the experimental reach.

  7. Experimental studies of electron capture

    International Nuclear Information System (INIS)

    Pedersen, E.H.

    1983-01-01

    This thesis discusses the main results of recent experimental studies of electron capture in asymmetric collisions. Most of the results have been published, but the thesis also contains yet unpublished data, or data presented only in unrefereed conference proceedings. The thesis aims at giving a coherent discussion of the understanding of the experimental results, based first on simple qualitative considerations and subsequently on quantitative comparisons with the best theoretical calculations currently available. (Auth.)

  8. Electron Capture Cross Sections for Stellar Nucleosynthesis

    Directory of Open Access Journals (Sweden)

    P. G. Giannaka

    2015-01-01

    Full Text Available In the first stage of this work, we perform detailed calculations for the cross sections of the electron capture on nuclei under laboratory conditions. Towards this aim we exploit the advantages of a refined version of the proton-neutron quasiparticle random-phase approximation (pn-QRPA and carry out state-by-state evaluations of the rates of exclusive processes that lead to any of the accessible transitions within the chosen model space. In the second stage of our present study, we translate the abovementioned e--capture cross sections to the stellar environment ones by inserting the temperature dependence through a Maxwell-Boltzmann distribution describing the stellar electron gas. As a concrete nuclear target we use the 66Zn isotope, which belongs to the iron group nuclei and plays prominent role in stellar nucleosynthesis at core collapse supernovae environment.

  9. Atomic and nuclear parameters of single electron capture decaying nuclides; Constantes atomicas y nucleares de nucleidos que se desintegran por captura electronica pura

    Energy Technology Data Exchange (ETDEWEB)

    Grau, A

    1981-07-01

    Atomic and nuclear parameters of the following nuclides which decay by electron capture have been calculated: 37{sup A}r, 41{sup C}a, 49{sup V}, 53{sup M}n, 55{sup F}e,59{sup N}i, 68Ge,82{sup S}r, 97{sup T}c, 118{sup T}e, 131{sup C}s, 137{sup L}a, 140{sup N}d, 157{sup T}b, 165{sup E}r, 193{sup p}t, 194{sup H}g, and 205{sup P}h The evaluation rules are included in the first part of the paper. The values and the associated uncertainties of the following parameters have been tabulated: decay energy, electron capture probabilities, fluorescence yield, electron emission and X-ray emission. (Author) 27 refs.

  10. Introductory remarks on electron capture by multicharged ions

    International Nuclear Information System (INIS)

    Crandall, D.H.

    1979-01-01

    An overview is presented of applications of multicharged-ion electron capture and, through the qualitative assessment of availability of information, the general status of current understanding of such capture. A chart is given on which the various ion collision processes are related to other pertinent fields of physical research notably fusion, astrophysics, the solar corona, and lasers. The production and transport of ions is also noted. The symposium considers collision velocities less than 4 x 10 8 cm/s, where the capture cross sections are largest and where most of the available results are quite recent

  11. Probability of K atomic shell ionization by heavy particles impact, in functions of the scattering angle

    International Nuclear Information System (INIS)

    Oliveira, P.M.C. de.

    1976-12-01

    A method of calculation of the K atomic shell ionization probability by heavy particles impact, in the semi-classical approximation is presented. In this approximation, the projectile has a classical trajectory. The potential energy due to the projectile is taken as perturbation of the Hamiltonian of the neutral atom. We use scaled Thomas-Fermi wave function for the atomic electrons. The method is valid for intermediate atomic number elements and particle energies of some MeV. Probabilities are calculated for the case of Ag (Z = 47) and protons of 1 and 2 MeV. Results are given as function of scattering angle, and agree well known experimental data and also improve older calculations. (Author) [pt

  12. Rank-k Maximal Statistics for Divergence and Probability of Misclassification

    Science.gov (United States)

    Decell, H. P., Jr.

    1972-01-01

    A technique is developed for selecting from n-channel multispectral data some k combinations of the n-channels upon which to base a given classification technique so that some measure of the loss of the ability to distinguish between classes, using the compressed k-dimensional data, is minimized. Information loss in compressing the n-channel data to k channels is taken to be the difference in the average interclass divergences (or probability of misclassification) in n-space and in k-space.

  13. State-selective electron capture

    International Nuclear Information System (INIS)

    Dunford, R.W.; Liu, C.J.; Berry, H.G.; Pardo, R.C.; Raphaelian, M.L.A.

    1988-01-01

    We report results from a new atomic physics program using the Argonne PII ECR ion source which is being built as part of the upgrade of the Argonne Tandem-Linear Accelerator (ATLAS). Our initial experiments have been aimed at studying state-selective electron capture in ion-atom collisions using the technique of Photon Emission Spectroscopy. We are extending existing cross section measurements at low energy ( 6+ and O 7+ on He and H 2 targets in the energy range from 1-105 keV/amu. We also present uv spectra obtained in collisions of O 6+ , O 5+ and N 5+ on a sodium target. 4 refs., 2 figs., 1 tab

  14. Electron capture in pseudo-two-electron systems: Ar8++He

    International Nuclear Information System (INIS)

    Kimura, M.; Olson, R.E.

    1985-01-01

    Molecular-structure calculations using the pseudopotential method have been performed on the (ArHe) 8+ system. The cross section for single-electron capture in Ar 8+ +He collisions was calculated for energies from 20 eV to 10 keV/amu. The perturbed-stationary-state method [M. Kimura, H. Sato, and R. E. Olson, Phys. Rev. A 28, 2085 (1983)], modified to include electron translation factors appropriate to two-electron systems, was used. The total cross section is relatively energy independent with a value of approximately 2.5 x 10 -15 cm 2 . The n = 4 level of Ar 7+ is found to be preferentially populated, with the 4f level being dominant

  15. On the use of mean groundwater age, life expectancy and capture probability for defining aquifer vulnerability and time-of-travel zones for source water protection.

    Science.gov (United States)

    Molson, J W; Frind, E O

    2012-01-01

    Protection and sustainability of water supply wells requires the assessment of vulnerability to contamination and the delineation of well capture zones. Capture zones, or more generally, time-of-travel zones corresponding to specific contaminant travel times, are most commonly delineated using advective particle tracking. More recently, the capture probability approach has been used in which a probability of capture of P=1 is assigned to the well and the growth of a probability-of-capture plume is tracked backward in time using an advective-dispersive transport model. This approach accounts for uncertainty due to local-scale heterogeneities through the use of macrodispersion. In this paper, we develop an alternative approach to capture zone delineation by applying the concept of mean life expectancy E (time remaining before being captured by the well), and we show how life expectancy E is related to capture probability P. Either approach can be used to delineate time-of-travel zones corresponding to specific travel times, as well as the ultimate capture zone. The related concept of mean groundwater age A (time since recharge) can also be applied in the context of defining the vulnerability of a pumped aquifer. In the same way as capture probability, mean life expectancy and groundwater age account for local-scale uncertainty or unresolved heterogeneities through macrodispersion, which standard particle tracking neglects. The approach is tested on 2D and 3D idealized systems, as well as on several watershed-scale well fields within the Regional Municipality of Waterloo, Ontario, Canada. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Dipole-Guided Electron Capture Causes Abnormal Dissociations of Phosphorylated Pentapeptides

    DEFF Research Database (Denmark)

    Moss, Christopher L.; Chung, Thomas W.; Wyer, Jean

    2011-01-01

    energies and fluoranthene anion radicals in an ion trap resulted in the loss of a hydrogen atom, ammonia, and backbone cleavages forming complete series of sequence z ions. Elimination of phosphoric acid was negligible. In contrast, capture of lowenergy electrons by doubly charged ions in a Penning ion...... mapping of the potential energy surface provided structures for the precursor phosphopeptide dications. Electron attachment produces a multitude of low lying electronic states in charge-reduced ions that determine their reactivity in backbone dissociations and H- atom loss. The predominant loss of H atoms......Abstract Electron transfer and capture mass spectra of a series of doubly charged ions that were phosphorylated pentapeptides of a tryptic type (pS,A,A,A,R) showed conspicuous differences in dissociations of charge-reduced ions. Electron transfer from both gaseous cesium atoms at 100 keV kinetic...

  17. Investigation of the Mechanism of Electron Capture and Electron Transfer Dissociation of Peptides with a Covalently Attached Free Radical Hydrogen Atom Scavenger.

    Science.gov (United States)

    Sohn, Chang Ho; Yin, Sheng; Peng, Ivory; Loo, Joseph A; Beauchamp, J L

    2015-11-15

    The mechanisms of electron capture and electron transfer dissociation (ECD and ETD) are investigated by covalently attaching a free-radical hydrogen atom scavenger to a peptide. The 2,2,6,6-tetramethylpiperidin-l-oxyl (TEMPO) radical was chosen as the scavenger due to its high hydrogen atom affinity (ca. 280 kJ/mol) and low electron affinity (ca. 0.45 ev), and was derivatized to the model peptide, FQX TEMPO EEQQQTEDELQDK. The X TEMPO residue represents a cysteinyl residue derivatized with an acetamido-TEMPO group. The acetamide group without TEMPO was also examined as a control. The gas phase proton affinity (882 kJ/mol) of TEMPO is similar to backbone amide carbonyls (889 kJ/mol), minimizing perturbation to internal solvation and sites of protonation of the derivatized peptides. Collision induced dissociation (CID) of the TEMPO tagged peptide dication generated stable odd-electron b and y type ions without indication of any TEMPO radical induced fragmentation initiated by hydrogen abstraction. The type and abundance of fragment ions observed in the CID spectra of the TEMPO and acetamide tagged peptides are very similar. However, ECD of the TEMPO labeled peptide dication yielded no backbone cleavage. We propose that a labile hydrogen atom in the charge reduced radical ions is scavenged by the TEMPO radical moiety, resulting in inhibition of N-C α backbone cleavage processes. Supplemental activation after electron attachment (ETcaD) and CID of the charge-reduced precursor ion generated by electron transfer of the TEMPO tagged peptide dication produced a series of b + H (b H ) and y + H (y H ) ions along with some c ions having suppressed intensities, consistent with stable O-H bond formation at the TEMPO group. In summary, the results indicate that ECD and ETD backbone cleavage processes are inhibited by scavenging of a labile hydrogen atom by the localized TEMPO radical moiety. This observation supports the conjecture that ECD and ETD processes involve long

  18. Resonant electron capture by aspartame and aspartic acid molecules.

    Science.gov (United States)

    Muftakhov, M V; Shchukin, P V

    2016-12-30

    The processes for dissociative electron capture are the key mechanisms for decomposition of biomolecules, proteins in particular, under interaction with low-energy electrons. Molecules of aspartic acid and aspartame, i.e. modified dipeptides, were studied herein to define the impact of the side functional groups on peptide chain decomposition in resonant electron-molecular reactions. The processes of formation and decomposition of negative ions of both aspartame and aspartic acid were studied by mass spectrometry of negative ions under resonant electron capture. The obtained mass spectra were interpreted under thermochemical analysis by quantum chemical calculations. Main channels of negative molecular ions fragmentation were found and characteristic fragment ions were identified. The СООН fragment of the side chain in aspartic acid is shown to play a key role like the carboxyl group in amino acids and aliphatic oligopeptides. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Electron capture Auger aftereffect of ammine cobalt complex

    International Nuclear Information System (INIS)

    Harada, Masayuki; Sano, Hirotoshi

    1976-01-01

    The study of ammine cobalt complex by luminescent Moessbauer spectrometry method was performed. The method was compared with hot atom chemistry method. The electron states in atoms are changed by the aftereffect on Auger emission following the electron capture process. The state of oxidation of disintegration products is usually higher than that of parent nuclei. However, sometimes, lower oxidation is seen in Fe-57, the daughter nuclei of Co-57. This phenomenon may be due to radiation chemistry process, and this effect can be observed by the luminescent Moessbauer spectrometry method. However, the range of the effect can not be seen by the Moessbauer method. Estimation showed that the Auger electrons stay within the surrounding area of the disintegration atom, and the effect does not reach to distant places. The yield of Fe-57 in the electron capture process of Co-57 in cobalt complex, the G-value, and the hot atom chemical yield were obtained. It is concluded that the aftereffect of the Auger process is the localized radiation chemistry effect. Good correlation was seen between the present method and the hot atom chemistry method. (Kato, T.)

  20. Single-electron capture in He2+-D2 collisions

    International Nuclear Information System (INIS)

    Bordenave-Montesquieu, D.; Dagnac, R.

    1994-01-01

    Doubly differential cross sections of single-electron capture were measured for He 2+ impinging on a molecular deuterium target. The investigated collision energies are 4, 6 and 8 keV and the scattering angles range from 10' to 2 o 30' (laboratory frame). The exothermic capture leading to He + (1s) + D 2 +* was found to be the most important process at low energies and angles, whereas the endothermic channels leading to dissociative capture become the main processes at high scattering angles, i.e. at small impact parameters. (author)

  1. Electron-capture delayed fission properties of neutron-deficient einsteinium nuclei

    International Nuclear Information System (INIS)

    Shaughnessy, Dawn A.

    2000-01-01

    Electron-capture delayed fission (ECDF) properties of neutron-deficient einsteinium isotopes were investigated using a combination of chemical separations and on-line radiation detection methods. 242 Es was produced via the 233 U( 14 N,5n) 242 Es reaction at a beam energy of 87 MeV (on target) in the lab system, and was found to decay with a half-life of 11 ± 3 seconds. The ECDF of 242 Es showed a highly asymmetric mass distribution with an average pre-neutron emission total kinetic energy (TKE) of 183 ± 18 MeV. The probability of delayed fission (P DF ) was measured to be 0.006 ± 0.002. In conjunction with this experiment, the excitation functions of the 233 U( 14 N,xn) 247-x Es and 233 U( 15 N,xn) 248-x Es reactions were measured for 243 Es, 244 Es and 245 Es at projectile energies between 80 MeV and 100 MeV

  2. Quasi-resonant K-K charge transfer

    International Nuclear Information System (INIS)

    Hagmann, S.; Cocke, C.L.; Richard, P.; Skutlartz, A.; Kelbch, S.; Schmidt-Boecking, H.; Schuch, R.

    1983-01-01

    The impact parameter dependence, P(b), of single and double K to K charge transfer have been deduced from the coincidences between K-Auger electrons and scattered particles for F 9+ + Ne and F 9+ + Ne collisions at 10 MeV and 4.4 MeV. The 4.4 MeV single K-K transfer probability exhibits oscillations with b. The P(b) for delta-electron emission is also reported. To obtain more details on the mechanism, K-Auger electron-Ne recoil ion coincidences are measured for both F 8+ and F 9+ projectiles. The relative amounts of recoil ions and of satellite and hypersatellite Auger transitions vary substantially with projectile charge state. 11 references, 11 figures

  3. Theory of nuclear excitation by electron capture for heavy ions

    International Nuclear Information System (INIS)

    Palffy, Adriana; Scheid, Werner; Harman, Zoltan

    2006-01-01

    We investigate the resonant process of nuclear excitation by electron capture (NEEC), in which a continuum electron is captured into a bound state of an ion with the simultaneous excitation of the nucleus. In order to derive the cross section a Feshbach projection operator formalism is introduced. Nuclear states and transitions are described by a nuclear collective model and making use of experimental data. Transition rates and total cross sections for NEEC followed by the radiative decay of the excited nucleus are calculated for various heavy-ion collision systems

  4. Responses and mechanisms of positive electron affinity molecules in the N2 mode of the thermionic ionization detector and the electron-capture detector

    International Nuclear Information System (INIS)

    Jones, C.S.

    1989-01-01

    Very little knowledge has been acquired in the past on the mechanistic pathway by which molecules respond in the N 2 mode of the thermionic ionization detector. An attempt is made here to elucidate the response mechanism of the detector. The basic response mechanisms are known for the electron capture detector, and an attempt is made to identify the certain mechanism by which selected molecules respond. The resonance electron capture rate constant has been believed to be temperature independent, and investigations of the temperature dependence of electron capture responses are presented. Mechanisms for the N 2 mode of the thermionic ionization detector have been proposed by examining the detector response to positive electron affinity molecules and by measurement of the ions produced by the detector. Electron capture mechanisms for selected molecules have been proposed by examining their temperature dependent responses in the electron capture detector and negative ion mass spectra of the samples. In studies of the resonance electron capture rate constant, the relative responses of selected positive electron affinity molecules and their temperature dependent responses were investigated. Positive electron affinity did not guarantee large responses in the N 2 mode thermionic ionization detector. High mass ions were measured following ionization of samples in the detector. Responses in the electron capture detector varied with temperature and electron affinity

  5. Impact of electron-captures on nuclei near N = 50 on core-collapse supernovae

    Science.gov (United States)

    Titus, R.; Sullivan, C.; Zegers, R. G. T.; Brown, B. A.; Gao, B.

    2018-01-01

    The sensitivity of the late stages of stellar core collapse to electron-capture rates on nuclei is investigated, with a focus on electron-capture rates on 74 nuclei with neutron number close to 50, just above doubly magic 78Ni. It is demonstrated that variations in key characteristics of the evolution, such as the lepton fraction, electron fraction, entropy, stellar density, and in-fall velocity are about 50% due to uncertainties in the electron-capture rates on nuclei in this region, although thousands of nuclei are included in the simulations. The present electron-capture rate estimates used for the nuclei in this high-sensitivity region of the chart of isotopes are primarily based on a simple approximation, and it is shown that the estimated rates are likely too high, by an order of magnitude or more. Electron-capture rates based on Gamow-Teller strength distributions calculated in microscopic theoretical models will be required to obtain better estimates. Gamow-Teller distributions extracted from charge-exchange experiments performed at intermediate energies serve to guide the development and benchmark the models. A previously compiled weak-rate library that is used in the astrophysical simulations was updated as part of the work presented here, by adding additional rate tables for nuclei near stability for mass numbers between 60 and 110.

  6. Optical transition probabilities in electron-vibration-rotation spectra of diatomic molecules

    International Nuclear Information System (INIS)

    Kuznetsova, L.A.; Kuz'menko, N.E.; Kuzyakov, Yu.Ya.; Plastinin, Yu.A.

    1974-01-01

    The present review systematizes the data on the absolute probabilities of electron transitions in diatomic molecules, which have been published since the beginning of 1961 and up to the end of 1973, and those on the relative transition probabilities, which have been published since the beginning of 1966 till the end of 1973. The review discussed the theoretical relationships underlying the experimental techniques of determining the absolute transition probabilities. Modifications of the techniques under discussion are not specially examined; the details of interest can be found, however, in the references cited. The factual material-, such as the values of the absolute probabilities of electron transitions, the dependences of the electron transition moments on the internuclear distance and the values of the Franck-Condon factors,- is presented in tables 1, 2 and 4, respectively, embracing all the relevant works known to the present authors. Along with a complete systematization of the transition probability data, the authors have attempted a critical analysis of the available data in order to select the most reliable results. The recommended values of the squared matrix elements of the electron transition dipole moments are given in table 3. The last chaper of the work compares the results of calculations of the Franck-Condon factors obtained with the different milecular potentials [ru

  7. Thermal neutron capture cross section for the K isomer 177Lum

    International Nuclear Information System (INIS)

    Belier, G.; Roig, O.; Daugas, J.-M.; Giarmana, O.; Meot, V.; Letourneau, A.; Marie, F.; Foucher, Y.; Aupiais, J.; Abt, D.; Jutier, Ch.; Le Petit, G.; Bettoni, C.; Gaudry, A.; Veyssiere, Ch.; Barat, E.; Dautremer, T.; Trama, J.-Ch.

    2006-01-01

    The thermal neutron radiative capture cross section for the K isomeric state in 177 Lu has been measured for the first time. Several 177 Lu m targets have been prepared and irradiated in various neutron fluxes at the Lauee Langevin Institute in Grenoble and at the CEA reactors OSIRIS and ORPHEE in Saclay. The method consists of measuring the 178 Lu activity by γ-ray spectroscopy. The values obtained in four different neutron spectra have been used to calculate the resonance integral of the radiative capture cross section for 177 Lu m . In addition, an indirect method leads to the determination of the 177 Lu g neutron radiative capture cross section

  8. Experimental study on pion capture by hydrogen bound in molecules

    International Nuclear Information System (INIS)

    Horvath, D.; Aniol, K.A.; Entezami, F.; Measday, D.F.; Noble, A.J.; Stanislaus, S.; Virtue, C.J.

    1988-08-01

    An experiment was performed at TRIUMF to study the formation of pionic hydrogen atoms and molecules in solids, particularly in groups of organic molecules of slightly different structure in order to help further clarify the problem. The nuclear capture of pions by hydrogen was measured using the charge exchange of stopped pions. The coincident photons emitted by the decaying π 0 mesons were detected by TRIUMF's two large NaI spectrometers. New experimental results were obtained for the capture probability of stopped π - mesons in the nuclei of hydrogen atoms, chemically bound in molecules of some simple hydrides, acid anhydrides, and sugar isomers. A linear relation was found between pion capture in hydrogen and melting point in sugar isomers. The pion capture probability in acid anhydrides is fairly well described by a simple atomic capture model in which the capture probability on the hydrogen dramatically increases as the hydrogen atom is separated from the strongly electronegative C 2 O 3 group. Both effects are consistent with a correlation between pion capture and electron density on hydrogen atoms. (Author) (38 refs., 4 tabs., 7 figs.)

  9. Ionization and single electron capture in collision of highly charged Ar16+ ions with helium

    International Nuclear Information System (INIS)

    Wang Fei; Gou Bingcong

    2008-01-01

    This paper uses the two-centre atomic orbital close-coupling method to study the ionization and the single electron capture in collision of highly charged Ar 16+ ions with He atoms in the velocity range of 1.2–1.9 a.u. The relative importance of single ionization (SI) to single capture (SC) is explored. The comparison between the calculation and experimental data shows that the SI/SC cross section ratios from this work are in good agreement with experimental data. The total single electron ionization cross sections and the total single electron capture cross sections are also given for this collision. The investigation of the partial electron capture cross section shows a general tendency of capture to larger n and l with increasing velocity from 1.2 to 1.9 a.u

  10. Electron Capture in Proton Collisions with CO.

    Science.gov (United States)

    Stancil, P. C.; Schultz, D. R.; Kimura, M.; Gu, J.-P.; Hirsch, G.; Buenker, R. J.; Li, Y.

    1999-10-01

    Electron capture by protons following collisions with carbon monoxide is studied with a variety of theoretical approaches including quantal and semiclassical molecular-orbital close-coupling (MOCC) and classical trajectory Monte Carlo (CTMC) techniques. The MOCC treatments utilize potential surfaces and couplings computed for a range of H^+-CO orientation angles and C-O separations. Results including integral, differential, electronic state-selective, and vibrational state-selective cross sections will be presented for low- to intermediate-energies. Comparison with experiment will be made where possible and the relevance of the reaction in astrophysics and atmospheric physics will be discussed.

  11. Asymptotic coulombic conditions in the electron capture process

    International Nuclear Information System (INIS)

    Corchs, S.E.; Maidagan, J.M.; Rivarola, R.D.

    1990-01-01

    Several first order perturbative approximations of the transition amplitude for electronic capture are studied. Different models in which the long range Coulomb potential is represented by different internuclear dependent phases, in the initial and final wave functions, are analysed and compared. (Author). 8 refs., 2 figs

  12. Recent investigations on electronic capture in atomic collisions

    International Nuclear Information System (INIS)

    Rivarola, R.D.

    1988-01-01

    In this work, electron capture processes in ion-atom collisions at various impact energy ranges are dicussed: i) intermediate non-relativistic energy; ii) high energy; iii) high relativistic energy. Much attention is given to the development and use of distorted wave models. (A.C.A.S.) [pt

  13. Search for new candidates for the neutrino-oriented mass determination by electron-capture

    CERN Multimedia

    Herfurth, F; Boehm, C; Blaum, K; Beck, D

    2008-01-01

    This proposal is part of an extended program dedicated to the neutrino-mass determination in the electron-capture sector, which aims at ultra-precise mass measurements by Penning traps in combination with cryogenic micro-calorimetry for atomic de-excitation measurements. Here, precise mass measurements with ISOLTRAP are proposed for the orbital electron-capture nuclides $^{194}$Hg and $^{202}$Pb, as well as their daughters, with the goal to determine accurately their Q-values. These values are expected to be the smallest ones among a great variety of known electron-capture precursors. Therefore, these nuclides are strong candidates for an improved electron-neutrino mass determination. We ask for 8 shifts of on-line beam at ISOLDE for mass measurements of $^{194}$Hg, $^{194}$ Au, $^{202}$Pb, and $^{202}$Tl at ISOLTRAP.

  14. Double electron capture by protons in collisions with H2

    International Nuclear Information System (INIS)

    Salazar-Zepeda, M.H.; Gleason, Cristian; Gonzalez, Eduardo; Gonzalez-Magana, O.; Hinojosa, Guillermo

    2010-01-01

    Double electron capture of protons in collisions with molecular hydrogen in the energy range 1.5-10 keV was studied by measuring the resulting H - velocity distributions. In this paper, a technique that provides experimental evidence about double capture mechanisms is proposed. In addition, cross-sections for this process were measured in the energy range of 1-5 keV.

  15. Electron capture by highly charged low-velocity ions

    International Nuclear Information System (INIS)

    Cocke, C.L.; Dubois, R.; Justiniano, E.; Gray, T.J.; Can, C.

    1982-01-01

    This paper describes the use of a fast heavy ion beam to produce, by bombardment of gaseous targets, highly-charged low-velocity recoil ions, and the use of these secondary ions in turn as projectiles in studies of electron capture and ionization in low-energy collision systems. The interest in collisions involving low-energy highly-charged projectiles comes both from the somewhat simplifying aspects of the physics which attend the long-range capture and from applications to fusion plasmas, astrophysics and more speculative technology such as the production of X-ray lasers. The ions of interest in such applications should have both electronic excitation and center-of-mass energies in the keV range and cannot be produced by simply stripping fast heavy ion beams. Several novel types of ion source have been developed to produce low-energy highly-charged ions, of which the secondary ion recoil source discussed in this paper is one. (Auth.)

  16. Electron capture and energy-gain spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Taulbjerg, K.

    1989-01-01

    The applicability of translation energy spectroscopy as a tool to determine individual reaction cross sections in atomic collisions is analyzed with special emphasis on the electron capture process in highly charged ion collisions. A condition is derived to separate between higher collision energies where translation energy spectroscopy is problem free and lower energies where strong overlap of individual spectra features prohibits an analysis of the total translation energy spectrum by means of a simple deconvolution procedure. 8 refs., 6 figs.

  17. Magnetar crust electron capture for {sup 55}Co and {sup 56}Ni

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jing-Jing; Liu, Dong-Mei [Hainan Tropical Ocean University, College of Marine Science and Technology, Sanya (China)

    2018-01-15

    Based on the relativistic mean-field effective interaction principle and random phase approximation theory in superstrong magnetic fields (SMFs), we present an analysis of the influence of SMFs on the electron Fermi energy, nuclear blinding energy, single-particle level structure and electron capture for {sup 55}Co, and {sup 56}Ni by the shell-model Monte Carlo method in the magnetar's crust. The electron capture rates increase by two orders of magnitude due to an increase in the electron Fermi energy and a change in single-particle level structure by SMFs. Then the rates decrease by more than two orders of magnitude due to an increase in the nuclear binding energy and a reduction in the electron Fermi energy by SMFs. (orig.)

  18. Electron correlations in single-electron capture from helium by fast protons and α particles

    International Nuclear Information System (INIS)

    Mancev, Ivan; Milojevic, Nenad

    2010-01-01

    Single-electron capture from heliumlike atomic systems by bare projectiles is investigated by means of the four-body boundary-corrected first Born approximation (CB1-4B). The effect of the dynamic electron correlation is explicitly taken into account through the complete perturbation potential. The quantum-mechanical post and prior transition amplitudes for single charge exchange encompassing symmetric and/or asymmetric collisions are derived in terms of two-dimensional real integrals in the case of the prior form and five-dimensional quadratures for the post form. An illustrative computation is performed for single-electron capture from helium by protons and α particles at intermediate and high impact energies. The role of dynamic correlations is examined as a function of increased projectile energy. The validity and utility of the proposed CB1-4B method is critically assessed in comparison with the existing experimental data for total cross sections, and excellent agreement is obtained.

  19. Direct and indirect stabilisation mechanisms in multiple electron capture

    Energy Technology Data Exchange (ETDEWEB)

    Roncin, P. [Paris-11 Univ., 91 - Orsay (France). Lab. de Collisions Atomiques et Moleculaires; Barat, M. [Paris-11 Univ., 91 - Orsay (France). Lab. de Collisions Atomiques et Moleculaires; Gaboriaud, M.N. [Paris-11 Univ., 91 -Orsay (France). Lab. de Collisions Atomiques et Moleculaires; Szilagyi, Z.S. [Paris-11 Univ., 91 - Orsay (France). Lab. de Collisions Atomiques et Moleculaires; Kazansky, A.K. [Paris-11 Univ., 91 - Orsay (France). Lab. de Collisions Atomiques et Moleculaires

    1995-05-01

    During the last years both experimental and theoretical works have focused on the problem of the stabilisation of two excited electrons on the projectile. In this contribution we would like to give experimental examples of the two suggested mechanisms and their extension to multiple electron capture. Our data are discussed together with those obtained with other experimental techniques and with theoretical predictions. (orig./WL).

  20. Electron capture by highly stripped ions

    International Nuclear Information System (INIS)

    Greenland, P.T.

    1981-06-01

    This review describes theories of electron capture suitable for the description of rearrangement collisions between atomic hydrogen and completely stripped projectiles with charge greater than unity. The region of impact velocity considered lies between 0.05 and 3 au, which is of technological importance in fusion power devices. The semiclassical, impact parameter formalism is discussed and the use of atomic expansions at medium impact velocity is described. Experimental results for both completely and partially stripped projectiles are reviewed. The use of a molecular basis at low energy, and the role of pseudocrossings peculiar to the two centre Coulomb interaction are described. Finally, purely classical techniques, in which the electron wavefunction is represented by an ensemble of Kepler orbits are considered. The review was completed in February 1981. (author)

  1. Electron capture cross-section of Au-Fe complex in silicon

    International Nuclear Information System (INIS)

    Ali, Akbar; Shafi, M; Majid, Abdul

    2006-01-01

    A deep level transient spectroscopy technique is applied to study the capture cross-section of an iron-gold complex. The thermal ionization energy obtained from emission rate data is found to be E c -0.36 eV. The Au-Fe complex is a single defect having a capture cross-section of 2.48x10 -16 cm 2 for electrons which is independent of temperature

  2. Differential cross sections for single-electron capture in He{sup 2+}-D collisions

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, D.; Dagnac, R. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France)]|[Toulouse-3 Univ., 31 (France)

    1995-06-14

    A translational energy spectroscopy technique was used to study single-electron capture into the He{sup +} (n = 2) and He{sup +} (n 3) states in He{sup 2+}-D collisions. Differential cross sections were determined at 4, 6 and 8 keV in the angular range 5`-1{sup o}30` (laboratory frame). As expected, single-electron capture into the n = 2 state was found to be the dominant process; total cross sections for capture into the He{sup +} (n = 3) state were compared to other experimental and theoretical results. (author).

  3. Potassium Capture by Kaolin, Part 2: K2CO3, KCI, and K2SO4

    DEFF Research Database (Denmark)

    Wang, Guoliang; Jensen, Peter Arendt; Wu, Hao

    2018-01-01

    residence time on the reaction was investigated. The results showed that the K-capture level (C-K) (g potassium reacted by per g kaolin available) of K2CO3 and KCI by kaolin generally followed the equilibrium predictions at temperatures above 1100 degrees C, when using a kaolin particle size of D50 = 5.......47 mu m and a residence time of 1.2 s. This revealed that a nearly full conversion was obtained without kinetic or transport limitations at the conditions applied. At 800 and 900 degrees C, the measured conversions were lower than the equilibrium predictions, indicating that the reactions were either...

  4. Measurements of Pair Production and Electron Capture from the Continuum in Heavy Particle Collisions

    CERN Multimedia

    2002-01-01

    Large transient Coulomb fields, which are generated in collisions of high-Z systems at sufficiently high energies, lead to copious production of electron-positron pairs. It has been suggested that these lepton pairs might mask signals arising from plasma phase interaction. Pair-production cross sections have been calculated by several authors with results which differ significantly from each other. Some of the electrons produced may be captured into bound states of the ion, thereby, reducing its charge state by one unit. This process which has been termed ``Electron Capture from Pair Production``, represents the only electron capture pro which increases with energy, and as such, will dominate all others in the ultrarelativistic energy regime. Ions having undergone this process would be lost from storage-type accelerators. The absolute cross sections for capture have been calculated with results which differ by as much as an order of magnitude. If as large as some of the calculations predict, Relativistic Heav...

  5. Indication of Electron Neutrino Appearance in the T2K experiment and its long-term implications

    CERN Multimedia

    CERN. Geneva

    2011-01-01

    T2K (Tokai-to-Kamioka) is a long-baseline neutrino oscillation experiment primarily searching for oscillations of muon neutrinos into electron neutrinos. T2K will also make precise measurements of the atmospheric oscillation parameters via muon neutrino disappearance. The experiment uses 30 GeV protons from the new J-PARC Main Ring accelerator, located in Tokai, Japan, to generate a conventional neutrino beam to the Super-Kamiokande far detector. The hadron production measurements of the NA61 experiment at CERN were used to predict the neutrino fluxes at the near and far detectors. The T2K oscillation analysis compares the rates of observed and predicted muon and electron neutrino candidates in the far detector. We present first results based on data accumulated from January 2010 to March 2011. Six electron neutrino events pass the selection criteria for electron appearance at Super-Kamiokande, whereas the expected number of background events is 1.5±0.3. The probability of a fluctuation of the back...

  6. Electron capture cross-section of Au-Fe complex in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Akbar; Shafi, M; Majid, Abdul [Advance Materials Physics Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad (Pakistan)

    2006-10-15

    A deep level transient spectroscopy technique is applied to study the capture cross-section of an iron-gold complex. The thermal ionization energy obtained from emission rate data is found to be E{sub c} -0.36 eV. The Au-Fe complex is a single defect having a capture cross-section of 2.48x10{sup -16} cm{sup 2} for electrons which is independent of temperature.

  7. Accelerated Electron-Beam Formation with a High Capture Coefficient in a Parallel Coupled Accelerating Structure

    Science.gov (United States)

    Chernousov, Yu. D.; Shebolaev, I. V.; Ikryanov, I. M.

    2018-01-01

    An electron beam with a high (close to 100%) coefficient of electron capture into the regime of acceleration has been obtained in a linear electron accelerator based on a parallel coupled slow-wave structure, electron gun with microwave-controlled injection current, and permanent-magnet beam-focusing system. The high capture coefficient was due to the properties of the accelerating structure, beam-focusing system, and electron-injection system. Main characteristics of the proposed systems are presented.

  8. Detection efficiency for radionuclides decaying by electron capture and gamma-Ray

    International Nuclear Information System (INIS)

    Grau, A.; Fernandez, A.

    1985-01-01

    In this paper, the electron capture partial counting efficiency vs the figure of merit for electron-capture and gamma-ray emitters has been computed. The radionuclides tabulated are 48 c r, 54 M n, 57 C o 56 N i, 72 S e, 73 A s, 85 S r, 88 Z r, 92 N b, 103 P d, 111 l n, 119 S b, 125 I , 139 C e and 152 D y. It has been assumed that the liquid is a toluene based scintillator solution in standard glass vials containing 15 cm 3 . (Author) 17 refs

  9. Electron capture to the continuum from atomic hydrogen

    International Nuclear Information System (INIS)

    Glass, G.A.; Engar, P.; Berry, S.D.; Breinig, M.; Deserio, R.; Elston, S.B.; Sellin, I.A.

    1984-01-01

    The first known measurement of the differential cross section for electron capture to the continuum(ECC) from atomic hydrogen is presented. A 12 MeV beam of C 6+ ions traversed a static target of atomic hydrogen produced by an electron impact heated dissociation oven. The resulting ECC spectrum was obtained with a channel electron multiplier detector mounted at the exit of a 160 0 spherical sector electrostatic spectrometer with an angular acceptance of 2 0 . The ECC spectrum clearly shows the asymmetry generally associated with ECC spectra from gaseous targets. The ratio of the singly differential cross section of H to that of H 2 was found to be 0.80. 16 references, 3 figures

  10. Transition probabilities between levels of K and K+; Probabilidades de transicion entre niveles en el atomo de potasio y en el ion K+

    Energy Technology Data Exchange (ETDEWEB)

    Campos, J.; Martin, A.

    1984-07-01

    In this work transition probabilities between Ievels of n < 11 for K and for the known of K+ are calculated. Two computer programs based on the Coulomb approximation and the most suitable coupling schemes has been used. Lifetimes of all these levels are also calculated. (Author)

  11. K and L X-ray emission intensities of some radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Verma, H R; Pal, D [Punjabi Univ., Patiala (India). Dept. of Physics

    1985-01-01

    The K and L x-ray emission intensities per 100 disintegrations have been calculated for some radionuclides using the latest adopted data for gamma-ray intensities, electron capture and internal conversion coefficients for the parent nuclides, fluorescence yield values, Coster-Kronig transition probabilities, average total number of primary L shell vacancies produced in the decay of K shell vacancies and emission rates for various shells and subshells for the daughter nuclei. The results are in good agreement with theoretical and experimental values for the K x-ray intensities. There are no experimental results available to compare with the present calculations for the L x-ray intensities; however, there is a marked discrepancy in the L..cap alpha.. and L..beta.. intensities available on the basis of theoretical estimates.

  12. Measurement of vacancy transfer probability from K to L shell using ...

    Indian Academy of Sciences (India)

    73, No. 4. — journal of. October 2009 physics pp. 711–718. Measurement of vacancy transfer probability from K to L shell using K-shell fluorescence yields. ¨O S¨O˘GÜT1,∗, E BÜYÜKKASAP2, A KÜC¸ ÜK¨ONDER1 and T TARAKC¸ IO ˇGLU1. 1Department of Physics, Faculty of Science and Letters, Kahramanmaras Sütçü ˙ ...

  13. Electron loss and capture from low-charge-state oxygen projectiles in methane

    International Nuclear Information System (INIS)

    Santos, A C F; Wolff, W; Sant’Anna, M M; Sigaud, G M; DuBois, R D

    2013-01-01

    Absolute cross sections for single- and double-electron loss and single- and multiple-electron capture of 15–1000 keV oxygen projectiles (q = −1, 0, 1, 2) colliding with the methane molecule are presented. The experimental data are used to examine cross-section scaling characteristics for the electron loss of various projectiles. In addition, a modified version of the free-collision model was employed for the calculation of the single- and total-electron-loss cross sections of oxygen projectiles presented in this work. The comparison of the calculated cross sections with the present experimental data shows very good agreement for projectile velocities above 1.0 au. The comparison of the present single-electron-capture cross sections with other projectiles having the same charge shows good agreement, and a common curve can be drawn through the different data sets. (paper)

  14. Determination of the Electron Neutrino Mass from Experiments on Electron-Capture Beta-Decay (EC)

    CERN Multimedia

    2002-01-01

    The aim of the programme is to measure the electron-neutrino mass, for which at present an upper limit of 500~eV is known. \\\\ \\\\ The experiment studies the shape of the internal bremsstrahlung spectrum in electron-capture near its upper end-point and deduces a mass from small shape changes completely analogous to those in the well-known determination of the electron antineutrino mass in the tritium beta-minus decay. \\\\ \\\\ In a low-energy bremsstrahlung process, the capture takes place from a virtual S state associated with a radiative P~@A~S electromagnetic transition, and the resonant nature of the process leads to important enhancements of the photon intensities at low energy, in particular near the resonance energies co (X-rays). This effect gives this type of experiment a chance to compete with experiments on continuous beta spectra. \\\\ \\\\ The programme concentrates on two long-lived isotopes: \\\\ \\\\ 1)~~|1|6|3Ho. The Q value for this isotope has been found to be 2.6-2.7 keV. A detector specially construct...

  15. K-shell x-ray production cross sections of selected elements Al to Ni for 4. 0 to 38. 0 MeV /sup 10/B ions. [Cross sections, 4. 0 to 38 MeV, binding energy, electron capture decay, PWBA, energy shifts, multiple ionization

    Energy Technology Data Exchange (ETDEWEB)

    Monigold, G.; McDaniel, F.D.; Duggan, J.L.; Mehta, R.; Rice, R.; Miller, P.D.

    1976-01-01

    K-Shell x-ray production cross sections for the target elements Sc, Ti, V, Mn, Fe, Co, and Ni were measured for incident /sup 10/B ions over the energy range 4.0 to 38.0 MeV. The cross section data were compared to the theoretical predictions of the binary encounter approximation (BEA); the plane wave born approximation (PWBA); and the PWBA modified to include corrections for increased binding energy (B), Coulomb deflection of the incident ion (C), orbital perturbation due to polarization (P), and relativistic effects (R). In addition, fluorescence yield variations (W/sub K/) and contributions to the cross sections from electron capture (EC) were included. It was found that the predictions of the fully modified PWBA with contributions from electron capture and fluorescence yield variations included provided the best fit to the experimental data over the entire energy range for each target element. The K..beta../K..cap alpha.. x-ray intensity ratios were compared to theoretical values that assume single hole ionization, and the x-ray energy shifts presented as a function of the energy of the incident ion. These two measurements provided confirmation of the occurrence of multiple ionization for /sup 10/B bombardment of target elements in the range 21 less than or equal to Z/sub 2/ less than or equal to 28.

  16. Can the neutrino mass be measured using /sup 163/Ho electron capture

    International Nuclear Information System (INIS)

    Bennett, C.L.

    1985-01-01

    The safest limit on the neutrino mass comes from allowing the interference amplitude to be a free parameter in a fit to Springer's inner bremsstrahlung data while fixing the Q value to its upper limit based on the results of the relative capture rates from F. Hartmann's data. Since /sup 163/Ho was the most promising electron capture candidate for a neutrino mass detector, it is unlikely that electron capture will ever compete with tritium beta decay in terms of sensitivity to neutrino mass. The best fundamental thing that can be said is that the limit of the difference in the mass of the neutrino and its anti-particle is smaller in absolute value than for any other fermion anti-fermion pair

  17. Revisiting the U-238 thermal capture cross section and gamma-raymission probabilities from Np-239 decay

    Energy Technology Data Exchange (ETDEWEB)

    Trkov, A.; Molnar, G.L.; Revay, Zs.; Mughabghab, S.F.; Firestone,R.B.; Pronyaev, V.G.; Nichols, A.L.; Moxon, M.C.

    2005-03-03

    The precise value of the thermal capture cross section of238U is uncertain, and evaluated cross sections from various sourcesdiffer by more than their assigned uncertainties. A number of theoriginal publications have been reviewed to assess the discrepant data,corrections were made for more recent standard cross sections andotherconstants, and one new measurement was analyzed. Due to the strongcorrelations in activation measurements, the gamma-ray emissionprobabilities from the beta decay of 239Np were also analyzed. As aresult of the analysis, a value of 2.683 +- 0.012 barns was derived forthe thermal capture cross section of 238U. A new evaluation of thegamma-ray emission probabilities from 239Np decay was alsoundertaken.

  18. Assembly for the measurement of the most probable energy of directed electron radiation

    International Nuclear Information System (INIS)

    Geske, G.

    1987-01-01

    This invention relates to a setup for the measurement of the most probable energy of directed electron radiation up to 50 MeV. The known energy-range relationship with regard to the absorption of electron radiation in matter is utilized by an absorber with two groups of interconnected radiation detectors embedded in it. The most probable electron beam energy is derived from the quotient of both groups' signals

  19. Search for two-neutrino double electron capture on 124Xe with the XMASS-I detector

    Directory of Open Access Journals (Sweden)

    K. Abe

    2016-08-01

    Full Text Available Double electron capture is a rare nuclear decay process in which two orbital electrons are captured simultaneously in the same nucleus. Measurement of its two-neutrino mode would provide a new reference for the calculation of nuclear matrix elements whereas observation of its neutrinoless mode would demonstrate lepton number violation. A search for two-neutrino double electron capture on 124Xe is performed using 165.9 days of data collected with the XMASS-I liquid xenon detector. No significant excess above background was observed and we set a lower limit on the half-life as 4.7×1021 years at 90% confidence level. The obtained limit has ruled out parts of some theoretical expectations. We obtain a lower limit on the 126Xe two-neutrino double electron capture half-life of 4.3×1021 years at 90% confidence level as well.

  20. ANISOTROPY EFFECTS IN ELECTRON-CAPTURE BY O6+ FROM ALIGNED NA-ASTERISK(3P)

    NARCIS (Netherlands)

    SCHLATMANN, AR; WIERSEMA, WP; HOEKSTRA, R; MORGENSTERN, R; OLSON, RE; PASCALE, J

    1994-01-01

    We report results of one electron capture by highly charged ions colliding with laser excited aligned Na*(3p). The 0 vi(10-->8) photon emission cross section after electron capture by the O6+ projectile is measured in the collision energy range 2-8 keV/amu. Effects of the Na*(3p) orbital alignment

  1. Electron capture isotopes as cosmic ray 'hydrometers'

    International Nuclear Information System (INIS)

    Raisbeck, G.M.; Comstock, G.; Perron, C.; Yiou, F.

    1975-01-01

    Following our earlier work, a computer program has been developed to investigate in detail the survival of pure electron capture isotopes in cosmic rays as a function of their propagation conditions. It is found that this survival is very insensitive to certain parameters such as the type of path length distribution, but very sensitive to the density of the medium in which they are formed. Observation of these isotopes may thus provide clues as to this density. (orig.) [de

  2. Electron-capture delayed fission properties of neutron-deficient einsteinium nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Shaughnessy, Dawn A. [Univ. of California, Berkeley, CA (United States)

    2000-01-01

    Electron-capture delayed fission (ECDF) properties of neutron-deficient einsteinium isotopes were investigated using a combination of chemical separations and on-line radiation detection methods. 242Es was produced via the 233U(14N,5n)242Es reaction at a beam energy of 87 MeV (on target) in the lab system, and was found to decay with a half-life of 11 ± 3 seconds. The ECDF of 242Es showed a highly asymmetric mass distribution with an average pre-neutron emission total kinetic energy (TKE) of 183 ± 18 MeV. The probability of delayed fission (PDF) was measured to be 0.006 ± 0.002. In conjunction with this experiment, the excitation functions of the 233U(14N,xn)247-xEs and 233U(15N,xn)248-xEs reactions were measured for 243Es, 244Es and 245Es at projectile energies between 80 MeV and 100 MeV.

  3. Limit on the radiative neutrinoless double electron capture of ^{36}Ar from GERDA Phase I

    Science.gov (United States)

    Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Barros, N.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; di Vacri, A.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Fedorova, O.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Csáthy, J. Janicskó; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Medinaceli, E.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Palioselitis, D.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Salathe, M.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schütz, A.-K.; Schulz, O.; Schwingenheuer, B.; Selivanenko, O.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Stepaniuk, M.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wilsenach, H.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    2016-12-01

    Neutrinoless double electron capture is a process that, if detected, would give evidence of lepton number violation and the Majorana nature of neutrinos. A search for neutrinoless double electron capture of ^{36}Ar has been performed with germanium detectors installed in liquid argon using data from Phase I of the GERmanium Detector Array ( Gerda) experiment at the Gran Sasso Laboratory of INFN, Italy. No signal was observed and an experimental lower limit on the half-life of the radiative neutrinoless double electron capture of ^{36}Ar was established: T_{1/2} > 3.6 × 10^{21} years at 90% CI.

  4. The Importance of Electron Captures in Core-Collapse Supernovae

    International Nuclear Information System (INIS)

    Langanke, K.; Sampaio, J.M.; Martinez-Pinedo, G.

    2004-01-01

    Nuclear physics plays an essential role in the dynamics of a type II supernova (a collapsing star). Recent advances in nuclear many-body theory allow now to reliably calculate the stellar weak-interaction processes involving nuclei. The most important process is the electron capture on finite nuclei with mass numbers A > 55. It is found that the respective capture rates, derived from modern many-body models, differ noticeably from previous, more phenomenological estimates. This leads to significant changes in the stellar trajectory during the supernova explosion, as has been found in state-of-the-art supernova simulations. (author)

  5. Electron thermalization distances and free-ion yields in dielectric fluids: Effect of electron scavengers

    International Nuclear Information System (INIS)

    Gee, N.; Freeman, G.R.

    1985-01-01

    Free-ion yields were measured in isobutane and in solutions containing sulfur hexafluoride, at densities from the liquid at 295 K to the supercritical fluid. A modified Onsager model was used to estimate the most probable thermalization distances b/sub GP/ (GP denotes a Gaussian power-law distribution). The density-normalized distance b/sub GP/d in isobutane increased from 6.3 x 10 -6 kg/m 2 at 295 K to a maximum of 10.5 x 10 -6 kg/m 2 at 395 K, and then decreased to 5.6 x 10 -6 kg/m 2 at 408 K (T/sub c/). The maximum, which is evidence of conduction-band enhancement of b/sub GP/, was suppressed in solutions containing small amounts of SF 6 . The SF 6 captured the electrons while they were still at epithermal energies, and terminated their flight away from their sibling ions. The values of b/sub GP/ and the free-ion yields were thereby decreased

  6. Warm Dark Matter Sterile Neutrinos in Electron Capture and Beta Decay Spectra

    Directory of Open Access Journals (Sweden)

    O. Moreno

    2016-01-01

    Full Text Available We briefly review the motivation to search for sterile neutrinos in the keV mass scale, as dark matter candidates, and the prospects to find them in beta decay or electron capture spectra, with a global perspective. We describe the fundamentals of the neutrino flavor-mass eigenstate mismatch that opens the possibility of detecting sterile neutrinos in such ordinary nuclear processes. Results are shown and discussed for the effect of heavy neutrino emission in electron capture in Holmium 163 and in two isotopes of Lead, 202 and 205, as well as in the beta decay of Tritium. We study the deexcitation spectrum in the considered cases of electron capture and the charged lepton spectrum in the case of Tritium beta decay. For each of these cases, we define ratios of integrated transition rates over different regions of the spectrum under study and give new results that may guide and facilitate the analysis of possible future measurements, paying particular attention to forbidden transitions in Lead isotopes.

  7. Derivation of capture and reaction cross sections from experimental quasi-elastic and elastic backscattering probabilities

    International Nuclear Information System (INIS)

    Sargsyan, V.V.; Adamian, G.G.; Antonenko, N.V.; Gomes, P.R.S.

    2014-01-01

    We suggest simple and useful methods to extract reaction and capture (fusion) cross sections from the experimental elastic and quasi-elastic backscattering data.The direct measurement of the reaction or capture (fusion) cross section is a difficult task since it would require the measurement of individual cross sections of many reaction channels, and most of them could be reached only by specific experiments. This would require different experimental setups not always available at the same laboratory and, consequently, such direct measurements would demand a large amount of beam time and would take probably some years to be reached. Because of that, the measurements of elastic scattering angular distributions that cover full angular ranges and optical model analysis have been used for the determination of reaction cross sections. This traditional method consists in deriving the parameters of the complex optical potentials which fit the experimental elastic scattering angular distributions and then of deriving the reaction cross sections predicted by these potentials. Even so, both the experimental part and the analysis of this latter method are not so simple. In the present work we present a much simpler method to determine reaction and capture (fusion) cross sections. It consists of measuring only elastic or quasi-elastic scattering at one backward angle, and from that, the extraction of the reaction or capture cross sections can easily be performed. (author)

  8. Theory of nuclear excitation by electron capture for heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Gagyi-Palffy, A.

    2006-07-01

    The resonant process of nuclear excitation by electron capture (NEEC) in collisions involving highly-charged ions has been investigated theoretically. NEEC is a rare recombination process in which a free electron is captured into a bound shell of an ion with the simultaneous excitation of the nucleus. Total cross sections for NEEC followed by the radiative decay of the excited nucleus are presented for various collision systems. The possibility to observe the NEEC in scattering experiments with trapped or stored ions was discussed focusing on the cases with the largest calculated resonance strength. As the photons emitted in different channels of the electron recombination process are indistinguishable in the total cross section, the interference between NEEC followed by the radiative decay of the nucleus and radiative recombination was investigated. The angular distribution of the emitted photons in the recombination process provides means to discern the two processes. Angular differential cross sections for the emitted photons in the case of E2 nuclear transitions were presented for several heavy elements. (orig.)

  9. Single-electron capture in He[sup 2+]-D[sub 2] collisions

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, D.; Dagnac, R. (Toulouse-3 Univ., 31 (France))

    1994-02-14

    Doubly differential cross sections of single-electron capture were measured for He[sup 2+] impinging on a molecular deuterium target. The investigated collision energies are 4, 6 and 8 keV and the scattering angles range from 10' to 2[sup o]30' (laboratory frame). The exothermic capture leading to He[sup +] (1s) + D[sub 2][sup +*] was found to be the most important process at low energies and angles, whereas the endothermic channels leading to dissociative capture become the main processes at high scattering angles, i.e. at small impact parameters. (author).

  10. Influence of the parameters of supplying pulses and polarization voltage on the signal and shape of current characteristics of the electron capture detector

    International Nuclear Information System (INIS)

    Lasa, J.; Sliwka, I.; Drozdowicz, B.

    1989-01-01

    The paper contains results of measurements of current characteristics and of the signal for the constant concentration of freon F-11 of the ECD supplied with pulse voltage of changeable time of pulse duration t p , amplitude U 1 and the time of pulse repetition t r . In the course of measurements the detector worked at temperature 573 K with the additional constant polarization voltage. The polarization voltage has been observed to cause the effect of hypercoulometry. The presented mathematical analysis helps to determine the values of the coefficient of efficiency of electron capture p, the coefficient of electron loss k D , the coefficient of collecting of electric charges by the anode k' 3 and the coefficient of collecting of electric charges by the detector cathode k u . The coefficients are determined on the basis of experimental measurements. An attempt of physical interpretation of calculated values of these coefficients and their dependence on the parameters of the pulses supplying the detector has been presented. This interpretation requires the assumption that in some pulse periods t r the concentration of positive ions in the detector considerably exceeds concentration n 0 + = √a xα e /V, where a is an efficiency of the carrier gas ionization, α e is the coefficient of the electron-ion recombination and V is the detector volume. This statement helping to describe the effects observed in the electron capture polarized by voltage U a contradicts the recognized concept that the concentration of positive ions in the detector does not exceed the concentration n 0 + . The paper shows that the detector of the cylindrical construction, supplied with a pulse voltage can be used for coulometric measurements and the voltage polarizing the cathode can cause an effect of hypercoulometry. 33 figs., 9 refs. (author)

  11. Single-electron capture in low-energy Ar6+-He collisions

    International Nuclear Information System (INIS)

    Akguengoer, K.; Kamber, E.Y.; Ferguson, S.M.

    1997-01-01

    Double differential cross sections for state-selective single-electron capture processes in Ar 6+ -He collisions have been measured at laboratory energies between 75 and 900 eV and scattering angles between 0 and 8 . At the lowest energy, the zero-angle spectrum shows capture into Ar 5+ (4p) to be the most important channel. However, as the scattering angle is increased, a second peak appears at angles ≥2 and becomes more pronounced relative to the 4p capture channel. The energy spectra are interpreted qualitatively in terms of the reaction windows, which are calculated using the single-crossing Landau-Zener model. Total and differential cross sections are also measured and compared with available measurements and calculations. (orig.)

  12. Measurements of Pair Production and Electron Capture from the Continuum in Heavy Particle Collisions

    CERN Multimedia

    2002-01-01

    % WA99 \\\\ \\\\ Large transient Coulomb fields, which are generated in collisions of high-Z systems at sufficiently high energies, lead to copious production of electron-positron pairs. It has been suggested that these lepton pairs might mask signals arising from plasma phase interaction. Pair-production cross-sections have been calculated by several authors with results that differ significantly from each other. For very heavy ions and high energies, multiple pairs are expected to be formed even in single peripheral collisions. Perturbative and nonperturbative treatments lead to various predictions for the fractions of multiple pair formation out of the total cross-sections. Some of the electrons produced will be captured into bound states of the ion, thereby, reducing its charge state by one unit. This process which has been termed $^{\\prime\\prime}$Electron Capture from Pair Production$^{\\prime\\prime}$, represents the only electron capture process which increases with energy, and as such, will dominate all oth...

  13. Low-energy electron collisions with metal clusters: Electron capture and cluster fragmentation

    International Nuclear Information System (INIS)

    Kresin, V.V.; Scheidemann, A.; Knight, W.D.

    1993-01-01

    The authors have carried out the first measurement of absolute cross sections for the interaction between electrons and size-resolved free metal clusters. Integral inelastic scattering cross sections have been determined for electron-Na n cluster collisions in the energy range from 0.1 eV to 30 eV. At energies ≤1 eV, cross sections increase with decreasing impact energies, while at higher energies they remain essentially constant. The dominant processes are electron attachment in the low-energy range, and collision-induced fragmentation at higher energies. The magnitude of electron capture cross sections can be quantitatively explained by the effect of the strong polarization field induced in the cluster by the incident electron. The cross sections are very large, reaching values of hundreds of angstrom 2 ; this is due to the highly polarizable nature of metal clusters. The inelastic interaction range for fragmentation collisions is also found to considerably exceed the cluster radius, again reflecting the long-range character of electron-cluster interactions. The important role played by the polarization interaction represents a bridge between the study of collision processes and the extensive research on cluster response properties. Furthermore, insight into the mechanisms of electron scattering is important for understanding production and detection of cluster ions in mass spectrometry and related processes

  14. Electron capture in collisions of S4+ with helium

    International Nuclear Information System (INIS)

    Wang, J.G.; Stancil, P.C.; Turner, A.R.; Cooper, D.L.; Schultz, D.R.; Rakovic, M.J.; Fritsch, W.; Zygelman, B.

    2002-01-01

    Charge transfer due to collisions of ground-state S 4+ (3s 2 1 S) ions with helium is investigated for energies between 0.1 meV u -1 and 10 MeV u -1 . Total and state-selective single electron capture (SEC) cross sections and rate coefficients are obtained utilizing the quantum mechanical molecular-orbital close-coupling (MOCC), atomic-orbital close-coupling (AOCC), classical trajectory Monte Carlo (CTMC) and continuum distorted wave methods. The MOCC calculations utilize ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained with the spin-coupled valence-bond approach. Previous data are limited to a calculation of the total SEC rate coefficient using the Landau-Zener model that is, in comparison to the results presented here, three orders of magnitude smaller. The MOCC SEC cross sections at low energy reveal a multichannel interference effect. True double capture is also investigated with the AOCC and CTMC approaches while autoionizing double capture and transfer ionization (TI) is explored with CTMC. SEC is found to be the dominant process except for E>200 keV u -1 when TI becomes the primary capture channel. Astrophysical implications are briefly discussed. (author)

  15. Electron capture in collisions of S4+ with helium

    Science.gov (United States)

    Wang, J. G.; Turner, A. R.; Cooper, D. L.; Schultz, D. R.; Rakovic, M. J.; Fritsch, W.; Stancil, P. C.; Zygelman, B.

    2002-07-01

    Charge transfer due to collisions of ground-state S4+(3s2 1S) ions with helium is investigated for energies between 0.1 meV u-1 and 10 MeV u-1. Total and state-selective single electron capture (SEC) cross sections and rate coefficients are obtained utilizing the quantum mechanical molecular-orbital close-coupling (MOCC), atomic-orbital close-coupling (AOCC), classical trajectory Monte Carlo (CTMC) and continuum distorted wave methods. The MOCC calculations utilize ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained with the spin-coupled valence-bond approach. Previous data are limited to a calculation of the total SEC rate coefficient using the Landau-Zener model that is, in comparison to the results presented here, three orders of magnitude smaller. The MOCC SEC cross sections at low energy reveal a multichannel interference effect. True double capture is also investigated with the AOCC and CTMC approaches while autoionizing double capture and transfer ionization (TI) is explored with CTMC. SEC is found to be the dominant process except for E>200 keV u-1 when TI becomes the primary capture channel. Astrophysical implications are briefly discussed.

  16. Comparison of the potentials used for the calculation of the resonant coherent electron capture and loss cross sections

    International Nuclear Information System (INIS)

    Pauly, N.; Dubus, A.; Roesler, M.

    2003-01-01

    For incident protons with velocities around 1 a.u., electron capture and loss processes are known to play an important role. In particular, electron emission as well as electronic stopping power are strongly influenced by the charge changing processes. Several different electron capture and loss processes have been identified [Solid State Phys. 43 (1990) 229], i.e. Auger valence band processes, shell processes and resonant coherent processes. In the latter, the incident projectile undergoes a periodic excitation due to the periodic crystalline potential so that an electron can be lost or captured. In the literature, several different choices have been made for the crystalline potential. It is precisely the aim of the present work to review and compare the various potentials used in the literature and to show the influence of this choice on the resonant coherent electron capture and loss cross sections

  17. Single-photon emission associated with double electron capture in F9+ + C collisions

    CERN Document Server

    Elkafrawy, Tamer; Tanis, John A; Warczak, Andrzej

    2016-01-01

    Radiative double electron capture (RDEC), the one-step process occurring in ion-atom collisions, has been investigated for bare fluorine ions colliding with carbon. RDEC is completed when two target electrons are captured to a bound state of a projectile simultaneously with the emission of a single photon. This work is a follow-up to our earlier measurement of RDEC for bare oxygen projectiles, thus providing a recipient system free of electron-related Coulomb fields in both cases and allowing for the comparison between the two collision systems as well as with available theoretical studies. The most significant mechanisms of x-ray emission that may contribute to the RDEC energy region as background processes are also addressed.

  18. Classical description of the electron capture to the continuum cusp formation in ion-atom collisions

    International Nuclear Information System (INIS)

    Illescas, Clara; Pons, B.; Riera, A.

    2002-01-01

    Classical calculations are used to describe the dynamics of the electron capture to the continuum (ECC) cusp formation in H + +He collisions. We illustrate the frontier character of the ECC electrons between capture and ionization, and confirm that it is a temporary capture, through projectile focusing, that is responsible for the ECC cusp. Furthermore, the cusp is not a divergence smoothed by the experiment, and is slightly shifted from the impact-velocity value because of the residual pull from the target after ionization. This shift is larger the smaller the nuclear velocity

  19. Electron capture study of Ar[sup 7+] + He(H[sub 2]) by U. V. spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bouchama, T. (Inst. de Physique, Univ. des Sciences et de la Technologie, Alger (Algeria)); El Motassadeq, A. (Lab. Traitement du Signal et Instrumentation, Univ. Jean Monnet, 42 Saint-Etienne (France)); Salmoun, A. (Univ. Cady Ayad, Marrakech (Morocco)); Druetta, M. (Lab. Traitement du Signal et Instrumentation, Univ. Jean Monnet, 42 Saint-Etienne (France)); Church, D.A. (Dept. of Physics, Texas AM Univ., College Station, TX (United States))

    1993-11-01

    Partial nl and total cross-sections for the low energy collisions Ar[sup 7+] + He(H[sub 2]) at 35-70 keV have been measured by photon spectroscopy. In addition to single electron capture, one electron capture with excitation of a core electron has been observed and measured. Comparisons with calculations based on the Extended Classical Over-Barrier (ECB) model and the assumption of conservation of angular momentum show good agreement between the experimental and predicted l-distributions. (orig.).

  20. Single and double electron capture in collisions of highly ionized, decelerated Ge ions with Ne

    International Nuclear Information System (INIS)

    Stoehlker, T.; Kozhuharov, C.; Mokler, P.H.; Olson, R.E.; Stachura, Z.; Warczak, A.

    1992-03-01

    Experimental cross-sections for non-radiative single and double electron capture from Ne target into H-like Ge ions at low intermediate collision energies (4-12) MeV/u are presented. The results are compared with theoretical calculations and an empirical scaling rule. Information concerning the impact parameter dependence of electron capture is extracted using classical trajectory Monte Carlo calculations. (orig.)

  1. K-capture by Al-Si based Additives in an Entrained Flow Reactor

    DEFF Research Database (Denmark)

    Wang, Guoliang; Jensen, Peter Arendt; Wu, Hao

    2016-01-01

    A water slurry, consisting of KCl and Al-Si based additives (kaolin and coal fly ash) was fed into an entrained flow reactor (EFR) to study the K-capturing reaction of the additives at suspension-fired conditions. Solid products collected from the reactor were analysed with respect to total...... of KCl to K-aluminosilicate decreased. When reaction temperature increased from 1100 °C to 1450 °C, the conversion of KCl does not change significantly, which differs from the trend observed in fixed-bed reactor....

  2. State-selective electron capture into He-like U90+ ions in collisions with gaseous targets

    International Nuclear Information System (INIS)

    Ma, X.; Stoehlker, T.; Brinzanescu, O.; Fritzsche, S.; Ludziejewski, T.; Stachura, Z.; Warczak, A.

    2000-11-01

    For He-like uranium, a state-selective electron capture study was carried out for relativistic collisions with gaseous targets. In the experiment, the projectile X-ray emission produced by electron capture in collisions of 223 MeV/u U 90+ ions on N 2 , Ar, Kr, and Xe targets was measured in coincidence with down-charged U 89+ projectiles. Due to the large fine structure splitting in heavy ions, the well resolved Balmer transitions observed were used to deduce subshell sensitive cross-sections for electron capture. For this purpose a theoretical spectrum analysis and simulation was performed by taking into account electron cascades from states up to n = 40. The state-selective data are compared with theoretical calculations as a function of target atomic number. An overall agreement is found between the experimental data and the theoretical approaches applied except for the j-sensitive part. (orig.)

  3. Electron capture by fast protons from helium-like ions

    International Nuclear Information System (INIS)

    Samanta, R.; Purkait, M.

    2011-01-01

    Four-body formalism of boundary corrected continuum intermediate state (BCCIS-4B) approximation have been applied to calculate the single-electron capture cross sections by fast protons through some helium-like ions in a large energy range from 30-1000 keV. In this model, distortion has been taken into account in the entrance channel. In the final channel, the passive electron plays the role of screening of the target ion. However, continuum states of the projectile and the electron in the field of the residual target ion are included. The comparison of the results is made with those of other theoretical investigations and experimental findings. The present calculated results are found to be in good agreement with the available experimental findings. (authors)

  4. Limit on the radiative neutrinoless double electron capture of "3"6Ar from GERDA Phase I

    International Nuclear Information System (INIS)

    Agostini, M.; Balata, M.; D'Andrea, V.; Di Vacri, A.; Junker, M.; Laubenstein, M.; Allardt, M.; Domula, A.; Lehnert, B.; Schneider, B.; Wester, T.; Wilsenach, H.; Zuber, K.; Bakalyarov, A.M.; Belyaev, S.T.; Lebedev, V.I.; Zhukov, S.V.; Barabanov, I.; Bezrukov, L.; Doroshkevich, E.; Fedorova, O.; Gurentsov, V.; Kazalov, V.; Kuzminov, V.V.; Lubsandorzhiev, B.; Moseev, P.; Selivanenko, O.; Veresnikova, A.; Yanovich, E.; Barros, N.; Baudis, L.; Benato, G.; Kish, A.; Miloradovic, M.; Mingazheva, R.; Walter, M.; Bauer, C.; Hakenmueller, J.; Heisel, M.; Heusser, G.; Hofmann, W.; Kihm, T.; Kirsch, A.; Knoepfle, K.T.; Lindner, M.; Maneschg, W.; Salathe, M.; Schreiner, J.; Schwingenheuer, B.; Simgen, H.; Smolnikov, A.; Stepaniuk, M.; Wagner, V.; Wegmann, A.; Bellotti, E.; Belogurov, S.; Kornoukhov, V.N.; Bettini, A.; Brugnera, R.; Garfagnini, A.; Medinaceli, E.; Sada, C.; Sturm, K. von; Bode, T.; Csathy, J.J.; Lazzaro, A.; Schoenert, S.; Wiesinger, C.; Borowicz, D.; Brudanin, V.; Egorov, V.; Kochetov, O.; Nemchenok, I.; Rumyantseva, N.; Zhitnikov, I.; Zinatulina, D.; Caldwell, A.; Gooch, C.; Kneissl, R.; Liao, H.Y.; Majorovits, B.; Palioselitis, D.; Schulz, O.; Vanhoefer, L.; Cattadori, C.; Salamida, F.; Chernogorov, A.; Demidova, E.V.; Kirpichnikov, I.V.; Vasenko, A.A.; Falkenstein, R.; Freund, K.; Grabmayr, P.; Hegai, A.; Jochum, J.; Schmitt, C.; Schuetz, A.K.; Frodyma, N.; Misiaszek, M.; Panas, K.; Pelczar, K.; Wojcik, M.; Zuzel, G.; Gangapshev, A.; Gusev, K.; Hemmer, S.; Lippi, I.; Stanco, L.; Hult, M.; Lutter, G.; Inzhechik, L.V.; Klimenko, A.; Lubashevskiy, A.; Macolino, C.; Pandola, L.; Pullia, A.; Riboldi, S.; Shirchenko, M.

    2016-01-01

    Neutrinoless double electron capture is a process that, if detected, would give evidence of lepton number violation and the Majorana nature of neutrinos. A search for neutrinoless double electron capture of "3"6Ar has been performed with germanium detectors installed in liquid argon using data from Phase I of the GERmanium Detector Array (Gerda) experiment at the Gran Sasso Laboratory of INFN, Italy. No signal was observed and an experimental lower limit on the half-life of the radiative neutrinoless double electron capture of "3"6Ar was established: T_1_/_2 > 3.6 x 10"2"1 years at 90% CI. (orig.)

  5. Limit on the radiative neutrinoless double electron capture of {sup 36}Ar from GERDA Phase I

    Energy Technology Data Exchange (ETDEWEB)

    Agostini, M.; Balata, M.; D' Andrea, V.; Di Vacri, A.; Junker, M.; Laubenstein, M. [INFN Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, Assergi (Italy); Allardt, M.; Domula, A.; Lehnert, B.; Schneider, B.; Wester, T.; Wilsenach, H.; Zuber, K. [Technische Universitaet Dresden, Institut fuer Kern- und Teilchenphysik, Dresden (Germany); Bakalyarov, A.M.; Belyaev, S.T.; Lebedev, V.I.; Zhukov, S.V. [National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Barabanov, I.; Bezrukov, L.; Doroshkevich, E.; Fedorova, O.; Gurentsov, V.; Kazalov, V.; Kuzminov, V.V.; Lubsandorzhiev, B.; Moseev, P.; Selivanenko, O.; Veresnikova, A.; Yanovich, E. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Barros, N. [Technische Universitaet Dresden, Institut fuer Kern- und Teilchenphysik, Dresden (Germany); University of Pennsylvania, Philadelphia, PA (United States); Baudis, L.; Benato, G.; Kish, A.; Miloradovic, M.; Mingazheva, R.; Walter, M. [Physik Institut der Universitaet Zuerich, Zurich (Switzerland); Bauer, C.; Hakenmueller, J.; Heisel, M.; Heusser, G.; Hofmann, W.; Kihm, T.; Kirsch, A.; Knoepfle, K.T.; Lindner, M.; Maneschg, W.; Salathe, M.; Schreiner, J.; Schwingenheuer, B.; Simgen, H.; Smolnikov, A.; Stepaniuk, M.; Wagner, V.; Wegmann, A. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Bellotti, E. [Universita Milano Bicocca, Dipartimento di Fisica, Milan (Italy); INFN Milano Bicocca, Milan (Italy); Belogurov, S.; Kornoukhov, V.N. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Institute for Theoretical and Experimental Physics NRC ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Bettini, A.; Brugnera, R.; Garfagnini, A.; Medinaceli, E.; Sada, C.; Sturm, K. von [Dipartimento di Fisica e Astronomia dell' Universita di Padova, Padua (Italy); INFN Padova, Padua (Italy); Bode, T.; Csathy, J.J.; Lazzaro, A.; Schoenert, S.; Wiesinger, C. [Technische Universitaet Muenchen, Physik Department and Excellence Cluster Universe, Munich (Germany); Borowicz, D. [Jagiellonian University, Institute of Physics, Krakow (Poland); Joint Institute for Nuclear Research, Dubna (Russian Federation); Brudanin, V.; Egorov, V.; Kochetov, O.; Nemchenok, I.; Rumyantseva, N.; Zhitnikov, I.; Zinatulina, D. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Caldwell, A.; Gooch, C.; Kneissl, R.; Liao, H.Y.; Majorovits, B.; Palioselitis, D.; Schulz, O.; Vanhoefer, L. [Max-Planck-Institut fuer Physik, Munich (Germany); Cattadori, C.; Salamida, F. [INFN Milano Bicocca, Milan (Italy); Chernogorov, A.; Demidova, E.V.; Kirpichnikov, I.V.; Vasenko, A.A. [Institute for Theoretical and Experimental Physics NRC ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Falkenstein, R.; Freund, K.; Grabmayr, P.; Hegai, A.; Jochum, J.; Schmitt, C.; Schuetz, A.K. [Eberhard Karls Universitaet Tuebingen, Physikalisches Institut, Tuebingen (Germany); Frodyma, N.; Misiaszek, M.; Panas, K.; Pelczar, K.; Wojcik, M.; Zuzel, G. [Jagiellonian University, Institute of Physics, Krakow (Poland); Gangapshev, A. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Gusev, K. [Joint Institute for Nuclear Research, Dubna (Russian Federation); National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Technische Universitaet Muenchen, Physik Department and Excellence Cluster Universe, Munich (Germany); Hemmer, S.; Lippi, I.; Stanco, L. [INFN Padova, Padua (Italy); Hult, M.; Lutter, G. [European Commission, JRC-Geel, Geel (Belgium); Inzhechik, L.V. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Moscow Institute of Physics and Technology, Moscow (Russian Federation); Klimenko, A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); International University for Nature, Society and Man ' ' Dubna' ' , Dubna (Russian Federation); Lubashevskiy, A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Macolino, C. [INFN Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, Assergi (Italy); LAL, CNRS/IN2P3, Universite Paris-Saclay, Orsay (France); Pandola, L. [INFN Laboratori Nazionali del Sud, Catania (Italy); Pullia, A.; Riboldi, S. [Universita degli Studi di Milano, Dipartimento di Fisica, Milan (Italy); INFN Milano (Italy); Shirchenko, M. [Joint Institute for Nuclear Research, Dubna (Russian Federation); National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Collaboration: GERDA collaboration

    2016-12-15

    Neutrinoless double electron capture is a process that, if detected, would give evidence of lepton number violation and the Majorana nature of neutrinos. A search for neutrinoless double electron capture of {sup 36}Ar has been performed with germanium detectors installed in liquid argon using data from Phase I of the GERmanium Detector Array (Gerda) experiment at the Gran Sasso Laboratory of INFN, Italy. No signal was observed and an experimental lower limit on the half-life of the radiative neutrinoless double electron capture of {sup 36}Ar was established: T{sub 1/2} > 3.6 x 10{sup 21} years at 90% CI. (orig.)

  6. First Calorimetric Measurement of OI-line in the Electron Capture Spectrum of $^{163}$Ho

    CERN Document Server

    Ranitzsch, P. C. -O.; Wegner, M.; Kempf, S.; Fleischmann, A.; Enss, C.; Gastaldo, L.; Herlert, A.; Johnston, K.

    2014-01-01

    The isotope $^{163}$Ho undergoes an electron capture process with a recommended value for the energy available to the decay, $Q_{\\rm EC}$, of about 2.5 keV. According to the present knowledge, this is the lowest $Q_{\\rm EC}$ value for electron capture processes. Because of that, $^{163}$Ho is the best candidate to perform experiments to investigate the value of the electron neutrino mass based on the analysis of the calorimetrically measured spectrum. We present for the first time the calorimetric measurement of the atomic de-excitation of the $^{163}$Dy daughter atom upon the capture of an electron from the 5s shell in $^{163}$Ho, OI-line. The measured peak energy is 48 eV. This measurement was performed using low temperature metallic magnetic calorimeters with the $^{163}$Ho ion implanted in the absorber. We demonstrate that the calorimetric spectrum of $^{163}$Ho can be measured with high precision and that the parameters describing the spectrum can be learned from the analysis of the data. Finally, we dis...

  7. Gene-specific characterization of human histone H2B by electron capture dissociation.

    Science.gov (United States)

    Siuti, Nertila; Roth, Michael J; Mizzen, Craig A; Kelleher, Neil L; Pesavento, James J

    2006-02-01

    The basis set of protein forms expressed by human cells from the H2B gene family was determined by Top Down Mass Spectrometry. Using Electron Capture Dissociation for MS/MS of H2B isoforms, direct evidence for the expression of unmodified H2B.Q, H2B.A, H2B.K/T, H2B.J, H2B.E, H2B.B, H2B.F, and monoacetylated H2B.A was obtained from asynchronous HeLa cells. H2B.A was the most abundant form, with the overall expression profile not changing significantly in cells arrested in mitosis by colchicine or during mid-S, mid-G2, G2/M, and mid-G1 phases of the cell cycle. Modest hyperacetylation of H2B family members was observed after sodium butyrate treatment.

  8. Real-time capture and reconstruction system with multiple GPUs for a 3D live scene by a generation from 4K IP images to 8K holograms.

    Science.gov (United States)

    Ichihashi, Yasuyuki; Oi, Ryutaro; Senoh, Takanori; Yamamoto, Kenji; Kurita, Taiichiro

    2012-09-10

    We developed a real-time capture and reconstruction system for three-dimensional (3D) live scenes. In previous research, we used integral photography (IP) to capture 3D images and then generated holograms from the IP images to implement a real-time reconstruction system. In this paper, we use a 4K (3,840 × 2,160) camera to capture IP images and 8K (7,680 × 4,320) liquid crystal display (LCD) panels for the reconstruction of holograms. We investigate two methods for enlarging the 4K images that were captured by integral photography to 8K images. One of the methods increases the number of pixels of each elemental image. The other increases the number of elemental images. In addition, we developed a personal computer (PC) cluster system with graphics processing units (GPUs) for the enlargement of IP images and the generation of holograms from the IP images using fast Fourier transform (FFT). We used the Compute Unified Device Architecture (CUDA) as the development environment for the GPUs. The Fast Fourier transform is performed using the CUFFT (CUDA FFT) library. As a result, we developed an integrated system for performing all processing from the capture to the reconstruction of 3D images by using these components and successfully used this system to reconstruct a 3D live scene at 12 frames per second.

  9. Location Prediction Based on Transition Probability Matrices Constructing from Sequential Rules for Spatial-Temporal K-Anonymity Dataset

    Science.gov (United States)

    Liu, Zhao; Zhu, Yunhong; Wu, Chenxue

    2016-01-01

    Spatial-temporal k-anonymity has become a mainstream approach among techniques for protection of users’ privacy in location-based services (LBS) applications, and has been applied to several variants such as LBS snapshot queries and continuous queries. Analyzing large-scale spatial-temporal anonymity sets may benefit several LBS applications. In this paper, we propose two location prediction methods based on transition probability matrices constructing from sequential rules for spatial-temporal k-anonymity dataset. First, we define single-step sequential rules mined from sequential spatial-temporal k-anonymity datasets generated from continuous LBS queries for multiple users. We then construct transition probability matrices from mined single-step sequential rules, and normalize the transition probabilities in the transition matrices. Next, we regard a mobility model for an LBS requester as a stationary stochastic process and compute the n-step transition probability matrices by raising the normalized transition probability matrices to the power n. Furthermore, we propose two location prediction methods: rough prediction and accurate prediction. The former achieves the probabilities of arriving at target locations along simple paths those include only current locations, target locations and transition steps. By iteratively combining the probabilities for simple paths with n steps and the probabilities for detailed paths with n-1 steps, the latter method calculates transition probabilities for detailed paths with n steps from current locations to target locations. Finally, we conduct extensive experiments, and correctness and flexibility of our proposed algorithm have been verified. PMID:27508502

  10. Electron capture in ion atom and ion-ion collisions

    International Nuclear Information System (INIS)

    Barat, M.

    1986-01-01

    Electron capture (EC) by positive ions in collision with various targets has remained one of the most important subjects of research since the early 30's. From a theoretical point of view, EC is obviously a coupled 3-body problem: at least two cores and an active electron that jumps between them. Practical interest in EC arose in a variety of fields. Recently a renewed interest arose from the physics of thermonuclear fusion, where capture by highly charged ionic impurities were found to be an important process in tokamak devices. For that reasons, a number of reviews were devoted to this subject during the past years, including lectures given in various NATO advanced science institutes. The aim of this lecture is not at all to add a new review to this list, but (i) to summarize the very basis of the present theoretical approaches at low and moderate collision energy, (ii) to pinpoint some crucial difficulties in the theoretical treatment, (iii) to select specific examples which, to the taste of the author, reflect some present practical interest, or some significant advances. 48 references, 38 figures, 1 table

  11. Testing the Pauli Exclusion Principle for electrons at LNGS

    CERN Document Server

    Shi, H.; Bertolucci, S.; Berucci, C.; Bragadireanu, A.M.; Cargnelli, M.; Clozza, A.; Curceanu, C.; De Paolis, L.; Di Matteo, S.; d'Uffizi, A.; Egger, J.-P.; Guaraldo, C.; Iliescu, M.; Ishiwatari, T.; Marton, J.; Laubenstein, M.; Milotti, E.; Pietreanu, D.; Piscicchia, K.; Ponta, T.; Romero Vidal, A.; Sbardella, E.; Scordo, A.; Sirghi, D.L.; Sirghi, F.; Sperandio, L.; Vazquez Doce, O.; Widmann, E.; Zmeskal, J.

    High-precision experiments have been done to test the Pauli exclusion principle (PEP) for electrons by searching for anomalous $K$-series X-rays from a Cu target supplied with electric current. With the highest sensitivity, the VIP (VIolation of Pauli Exclusion Principle) experiment set an upper limit at the level of $10^{-29}$ for the probability that an external electron captured by a Cu atom can make the transition from the 2$p$ state to a 1$s$ state already occupied by two electrons. In a follow-up experiment at Gran Sasso, we aim to increase the sensitivity by two orders of magnitude. We show proofs that the proposed improvement factor is realistic based on the results from recent performance tests of the detectors we did at Laboratori Nazionali di Frascati (LNF).

  12. Theoretical treatment of electron capture and excitation in two-electron system ion-atom, atom-atom collisions at low to intermediate energy

    International Nuclear Information System (INIS)

    Kimura, M.

    1986-01-01

    A review of various theoretical treatments which have been used to study electron-capture and excitation processes in two-electron-system ion-atom, atom-atom collisions at low to intermediate energy is presented. Advantages as well as limitations associated with these theoretical models in application to practical many-electron ion-atom, atom-atom collisions are specifically pointed out. Although a rigorous theoretical study of many-electron systems has just begun so that reports of theoretical calculations are scarce to date in comparison to flourishing experimental activities, some theoretical results are of great interest and provide important information for understanding collision dynamics of the system which contains many electrons. Selected examples are given for electron capture in a multiply charged ion-He collision, ion-pair formation in an atom-atom collision and alignment and orientation in a Li + + He collision. (Auth.)

  13. A mobile and asynchronous electronic data capture system for epidemiologic studies.

    Science.gov (United States)

    Meyer, Jens; Fredrich, Daniel; Piegsa, Jens; Habes, Mohamad; van den Berg, Neeltje; Hoffmann, Wolfgang

    2013-06-01

    A Central Data Management (CDM) system based on electronic data capture (EDC) software and study specific databases is an essential component for assessment and management of large data volumes in epidemiologic studies. Conventional CDM systems using web applications for data capture depend on permanent access to a network. However, in many study settings permanent network access cannot be guaranteed, e.g. when participants/patients are visited in their homes. In such cases a different concept for data capture is needed. The utilized EDC software must be able to ensure data capture as stand-alone instance and to synchronize captured data with the server at a later point in time. This article describes the design of the mobile information capture (MInCa) system an EDC software meeting these requirements. In particular, we focus on client and server design, data synchronization, and data privacy as well as data security measures. The MInCa software has already proven its efficiency in epidemiologic studies revealing strengths and weaknesses concerning both concept and practical application which will be addressed in this article. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  14. Single electron capture by state-prepared Ar2+ projectiles in Ar

    International Nuclear Information System (INIS)

    Puerta, J.; Huber, B.A.

    1985-03-01

    Electron capture by state-selected Ar 2+ projectiles in Ar has been studied at low collision energies ( 2+ ions are measured explaining existing discrepancies of partial and total cross sections in the Ar 2+ /Ar collision system. Although highly excited metastable ions ( 5 D 4 0 , 3 F 4 0 ) represent a minor contamination of a non-prepared Ar 2+ beam (proportional1%), their contributions are found to dominate the capture process due to cross section values larger than 10 -15 cm 2 . (orig.)

  15. Measurement of the activity of electron capturing isotopes

    International Nuclear Information System (INIS)

    Szoerenyi, A.

    1980-01-01

    In order to measure precisely the activity of electron capturing isotopes, an equipment was constructed for the detection the X-photons, the Auger- and the conversing electrons by a high-pressure, gas-flow 4π proportional counter. The proportional counter and the NaI(Tl) scintillation counter are placed in a common lead-shielding, thus, the equipment is suited for the measurement of radioisotopes decaying in coincidence. The structure of the proportional counter and of the pressure-control system are detailed. As an example, the energy spectra of a 109 Cd solution, taken at different pressures, are published. At a pressure of 1.1 MPa the 3 peaks are well separated. The results of an international test, in which the radioactivity of a 57 Co sample was determined, are published, too. (L.E.)

  16. Electron capture from H(2s) by H+ at low energies

    International Nuclear Information System (INIS)

    Blanco, S.A.; Falcon, C.A.; Piacentini, R.D.

    1986-01-01

    Total cross sections for resonant electron capture by protons from metastable H(2s) targets have been computed in a six-state molecular close-coupling formalism. Transitions between degenerate sublevels of the L shell of the target occurring at large internuclear distances have been taken into account in the impact parameter approximation. Cross sections are presented for impact velocities between 0.05 and 0.3 au. The results are compared with theoretical calculations for capture from H(2s) by Li 3+ , C 6+ and N 7+ . (author)

  17. CRESU studies of electron attachment and Penning ionization at temperatures down to 48 K

    International Nuclear Information System (INIS)

    Le Garrec, J.L.; Mitchell, J.B.A.; Rowe, B.R.

    1996-01-01

    The object of the present report is to present results obtained for electron attachment and Penning ionization, obtained with the addition of a Langmuir probe to the measurement apparatus. Measurements of the rate coefficients for electron attachment and Penning ionization are performed using the standard techniques for the flow reactors. Rate coefficients for the Penning ionisation of argon, nitrogen molecule, oxygen molecule by helium metastable are presented. The results obtained concerning the attachment of electrons to SF 6 (non-dissociative), CCl 2 F 2 (producing Cl - ), and CF 3 Br as a function of temperature are presented. The differences observed, and the variation of the value of β below 100 K, provides evidence of the strong influence of the internal state (probably vibrational) of the CF 3 Br molecule on its dissociative attachment

  18. Interpretation of second Born amplitudes in electron capture

    International Nuclear Information System (INIS)

    McGuire, J.H.; Simony, P.R.; Weaver, O.L.; Macek, J.

    1982-01-01

    Exact sound Born amplitudes for 1s-1s electron capture are presented and interpreted in terms of contributions from intermediate states off the energy shell and on the energy shell. The classical model of Thomas corresponds to two-step scattering via one particular on-shell intermediate state. In the high-velocity limit for 1s-1s capture, this on-shell intermediate state of the Thomas model accounts for one-half of the total cross section, i.e., the second Born cross section. The other half comes from off-energy-shell intermediate states near the on-shell Thomas state. Above 5 MeV both the off-shell and on-shell amplitudes have a simple structure near the Thomas peak. Below 1 MeV, contributions from a broader range of intermediate states are evident in the amplitudes. Although the contribution from the Thomas state is not large below 1 MeV, other second Born effects are significant

  19. Influence of Magnetic Field Decay on Electron Capture in Magnetars ...

    Indian Academy of Sciences (India)

    Abstract. The de-excited energy of electron capture (EC) induced by magnetic field decay may be a new source for heating magnetar crust, so we do a quantitative calculation on EC process near the outer crust and analyse their influence on persistent X-ray radiation of magnetars, adopt- ing the experimental data or the ...

  20. Electron capture and excitation processes in H+-H collisions in dense quantum plasmas

    Science.gov (United States)

    Jakimovski, D.; Markovska, N.; Janev, R. K.

    2016-10-01

    Electron capture and excitation processes in proton-hydrogen atom collisions taking place in dense quantum plasmas are studied by employing the two-centre atomic orbital close-coupling (TC-AOCC) method. The Debye-Hückel cosine (DHC) potential is used to describe the plasma screening effects on the Coulomb interaction between charged particles. The properties of a hydrogen atom with DHC potential are investigated as a function of the screening strength of the potential. It is found that the decrease in binding energy of nl levels with increasing screening strength is considerably faster than in the case of the Debye-Hückel (DH) screening potential, appropriate for description of charged particle interactions in weakly coupled classical plasmas. This results in a reduction in the number of bound states in the DHC potential with respect to that in the DH potential for the same plasma screening strength, and is reflected in the dynamics of excitation and electron capture processes for the two screened potentials. The TC-AOCC cross sections for total and state-selective electron capture and excitation cross sections with the DHC potential are calculated for a number of representative screening strengths in the 1-300 keV energy range and compared with those for the DH and pure Coulomb potential. The total capture cross sections for a selected number of screening strengths are compared with the available results from classical trajectory Monte Carlo calculations.

  1. Super-AGB Stars and their Role as Electron Capture Supernova Progenitors

    Science.gov (United States)

    Doherty, Carolyn L.; Gil-Pons, Pilar; Siess, Lionel; Lattanzio, John C.

    2017-11-01

    We review the lives, deaths and nucleosynthetic signatures of intermediate-mass stars in the range ≈6-12 M⊙, which form super-AGB stars near the end of their lives. The critical mass boundaries both between different types of massive white dwarfs (CO, CO-Ne, ONe), and between white dwarfs and supernovae, are examined along with the relative fraction of super-AGB stars that end life either as an ONe white dwarf or as a neutron star (or an ONeFe white dwarf), after undergoing an electron capture supernova event. The contribution of the other potential single-star channel to electron-capture supernovae, that of the failed massive stars, is also discussed. The factors that influence these different final fates and mass limits, such as composition, rotation, the efficiency of convection, the nuclear reaction rates, mass-loss rates, and third dredge-up efficiency, are described. We stress the importance of the binary evolution channels for producing electron-capture supernovae. Recent nucleosynthesis calculations and elemental yield results are discussed and a new set of s-process heavy element yields is presented. The contribution of super-AGB star nucleosynthesis is assessed within a Galactic perspective, and the (super-)AGB scenario is considered in the context of the multiple stellar populations seen in globular clusters. A brief summary of recent works on dust production is included. Last, we conclude with a discussion of the observational constraints and potential future advances for study into these stars on the low mass/high mass star boundary.

  2. Calculation of the detection efficiency in liquid scintillators. III. Single electron-capture radionuclides; Calculo de la eficiencia de deteccion en liquidos centelleadores. III. Nucleidos que se desintegran por captura electronica pura

    Energy Technology Data Exchange (ETDEWEB)

    Grau Malonda, A

    1982-07-01

    In this paper, counting efficiency vs figure of merit for 19 electron capture radionuclides has been computed. Toluene based s c i n t i l l a t o r solution of 15 cm{sup 3} has been assumed in the computation. The relationships to obtain the probability per decay are given and the computed efficiency tabulated.(Author)

  3. Single-electron capture in keV Ar15+...18++He collisions

    NARCIS (Netherlands)

    Knoop, S.; Fischer, D.; Xue, Y.; Zapukhlyak, M.; Osborne, C. J.; Ergler, Th; Ferger, T.; Braun, J.; Brenner, G.; Bruhns, H.; Dimopoulou, C.; Epp, S. W.; Martinez, A. J. Gonzalez; Sikler, G.; Orts, R. Soria; Tawara, H.; Kirchner, T.; Lopez-Urrutia, J. R. Crespo; Moshammer, R.; Ullrich, J.; Hoekstra, R.; Gonzales Martinez, A.J.

    2008-01-01

    Single-electron capture in 14 keV q(-1) Ar15+...18++He collisions is investigated both experimentally and theoretically. Partial cross sections and projectile scattering angle dependencies have been deduced from the target ion recoil momenta measured by the COLTRIMS technique. The comparison with

  4. Calculation of current-voltage characteristics of electron-capture detectors

    International Nuclear Information System (INIS)

    Hinneburg, D.; Grosse, H.J.; Leonhardt, J.; Popp, P.

    1983-01-01

    Starting from the law of conservation of charge a stationary one-dimensional non-linear differential equation system is derived, which is applied to the direct-current mode of an electron-capture detector with parallel electrode plates. The theory takes into account space-charge, recombination, and inhomogeneous ionization and it deals with three kinds of charge carriers with different mobilities (positive and negative ions, electrons). Terms due to diffusion and gas-flow losses are excluded. The equations so constructed were programmed to get a means of calculating the charge and field distributions and the current-voltage characteristics as functions of various parameters of the detectors, the attaching gas and the ionization. For two cases the results are given. (author)

  5. Electron capture into excited states of multi-charged ions

    International Nuclear Information System (INIS)

    Dijkkamp, D.

    1985-01-01

    This thesis deals with charge exchange reactions in slow collisions of multi-charged ions with neutral atoms or molecules. These reactions proceed very efficiently via a curve crossing mechanism, which leads to preferential population of excited states of the ion. The subsequent decay of these states leads to the emission of characteristic radiation. From wavelength resolved measurements of the absolute intensity of this radiation, cross sections for selective population of the excited (n,l-) states of the ion were determined. In addition, for some systems the total capture cross section was measured directly by means of charge state analysis of the secondary projectile ions. The role of charge exchange processes in fusion plasmas and in astrophysical plasmas is indicated. An experimental set-up is described with emphasis on the Electron Cyclotron Resonance Ion Source that was used in the experiments. Results for collisions of C 6+ , N 6+ , O 6+ and Ne 6+ with He, H 2 and Ar are presented as well as for electron capture from Li atoms by C 4+ and He 2+ . The interaction of the iso-electronic sequence C 4+ , N 5+ , O 6+ with atomic hydrogen, molecular hydrogen and helium is studied. First results for partial and total cross sections in collisions of fully stripped carbon, nitrogen and oxygen ions with atomic hydrogen are presented. These data are of particular importance for applications in fusion diagnostics. The data indicate that calculations of both molecular and atomic orbital type yield correct results, if an extended basis set is used. (Auth.)

  6. Radiative capture of slow electrons by tungsten surface

    International Nuclear Information System (INIS)

    Artamonov, O.M.; Belkina, G.M.; Samarin, S.N.; Yakovlev, I.I.

    1987-01-01

    Isochromatic spectra of radiation capture of slow electrons by the surface of mono- and polycrystal tungsten recorded on 322 and 405 nm wave lengths are presented. The effect of oxygen adsorption on isochromates of the (110) face of tungsten monocrystal is investigated. The obtained isochromatic spectra are compared with energy band structure of tungsten. Based on the analysis of the obtained experimental results it is assumed that optical transition to the final state at the energy of 7.3 eV relatively to Fermi level is conditioned by surface states of the tungsten face (110)

  7. Electron capture and ionization in collisions of multiply charged ions with H(2s)

    International Nuclear Information System (INIS)

    Errea, L F; Guzman, F; Illescas, Clara; Mendez, L; Pons, B; Riera, A; Suarez, J

    2007-01-01

    We present total cross sections for electron capture and ionization in collisions of B 5+ and Ne 10+ with H(2s), calculated using two methods: the semiclassical close-coupling molecular formalism and the eikonal-CTMC method. We have evaluated partial cross sections for capture into excited n-levels, required in plasma diagnostics

  8. Molecular treatment of single (dissociative and nondissociative) and double electron capture in He2+ + H2 collisions

    International Nuclear Information System (INIS)

    Errea, L F; Macias, A; Mendez, L; Pons, B; Riera, A

    2003-01-01

    We present close-coupling calculations of total cross sections for single and double electron capture in He 2+ + H 2 collisions in the range 0.5- 25 keV amu -1 , and compare them with experimental data. We confirm the experimental finding that the dominant process for E ∼> 3 keV amu -1 is the nondissociative capture He 2+ + H 2 → He + (2l) + H 2 + (1σ g ), while at lower energies it is dissociative capture leading to He + (1s) + H + + H. Our calculations also show that He(1s2l) is the main output of the two electron capture process. (letter to the editor)

  9. Quantum effects on the formation of negative hydrogen ion by polarization electron capture in partially ionized dense hydrogen plasmas

    International Nuclear Information System (INIS)

    Jung, Young-Dae; Kato, Daiji

    2009-05-01

    The quantum effects on the formation of the negative hydrogen ion (H - ) by the polarization electron capture process are investigated in partially ionized dense hydrogen plasmas. It is shown that the quantum effect strongly suppresses the electron capture radius as well as the cross section for the formation of the negative hydrogen ion. In addition, it has been found that the electron capture position is receded from the center of the projectile with decreasing the quantum effect of the plasma. (author)

  10. Electron capture dissociation proceeds with a low degree of intramolecular migration of peptide amide hydrogens

    DEFF Research Database (Denmark)

    Rand, Kasper D; Adams, Christopher M; Zubarev, Roman A

    2008-01-01

    scrambling) that occurs during vibrational excitation of gas-phase ions. Unlike traditional collisional ion activation, electron capture dissociation (ECD) is not associated with substantial vibrational excitation. We investigated the extent of intramolecular backbone amide hydrogen (1H/2H) migration upon...... ECD using peptides with a unique selective deuterium incorporation. Our results show that only limited amide hydrogen migration occurs upon ECD, provided that vibrational excitation prior to the electron capture event is minimized. Peptide ions that are excessively vibrationally excited...

  11. The Skyrme-TQRPA calculations of electron capture on hot nuclei in pre-supernova environment

    Energy Technology Data Exchange (ETDEWEB)

    Dzhioev, Alan A., E-mail: dzhioev@theor.jinr.ru; Vdovin, A. I., E-mail: vdovin@theor.jinr.ru [JINR, Bogoliubov Laboratory of Theoretical Physics (Russian Federation); Stoyanov, Ch., E-mail: stoyanov@inrne.bas.bg [Bulgarian Academy of Sciences, Institute for Nuclear Research and Nuclear Energy (Bulgaria)

    2016-11-15

    We combine the thermal QRPA approach with the Skyrme energy density functional theory (Skyrme–TQRPA) for modelling the process of electron capture on nuclei in supernova environment. For a sample nucleus, {sup 56}Fe, the Skyrme–TQRPA approach is applied to analyze thermal effects on the strength function of GT{sub +} transitions which dominate electron capture at E{sub e} ≤ 30 MeV. Several Skyrme interactions are used in order to verify the sensitivity of the obtained results to the Skyrme force parameters. Finite-temperature cross sections are calculated and the results are comparedwith those of the other model calculations.

  12. Two-electron capture into autoionising configurations N/sup 4 +/(1snln'l') with n = 2,3,4 and n' >= n, observed by electron spectrometry in collisions of N/sup 6 +/(1s) with He and H/sub 2/, at 4. 2 keV amu/sup -1/

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, A.; Benoit-Cattin, P.; Gleizes, A.; Marrakchi, A.I.; Dousson, S.; Hitz, D.

    1984-04-14

    Double electron transfer into autoionising states N/sup 4 +/(1snln'l'), with n = 2,3,4 and n' >= n has been observed in a collision between a one-electron highly charged N/sup 6 +/(1s) ion and a two-electron target (He or H/sub 2/), by electron spectrometry. The same configurations are excited in the two collisional systems but with very different probabilities. Electron capture mainly occurs into 1s2ln'l' in He-systems whereas transfer into 1s3ln'l' is stronger in H/sub 2/ systems.

  13. Electron-capture negative-ion mass spectrometry: a technique for environmental contaminant identification

    International Nuclear Information System (INIS)

    Stemmler, E.A.

    1986-01-01

    Electron capture negative ion mass spectrometry (ECNIMS) is a method used to generate negative ions in a mass spectrometer by electron-molecule reactions. This technique facilitates the sensitive and selective detection of many toxic contaminants in environmental samples. Applications of this technique have been hindered by the limited understanding of instrumental parameters, by the questionable reproducibility of negative ion mass spectra, and by the inability to interpret negative ion mass spectra. Instrumental parameters which were important to control include the ion source temperature, ion source pressure, sample concentration, and the focus lens potential. The ability to obtain reproducible spectra was demonstrated by measurement of the spectrum of decafluorotriphenylphosphine (DFTPP) over a period of one year. Negative ion fragmentation mechanisms were studied by measuring the spectra of structurally related classes of compounds and isotopically labelled compounds. These results were combined with data obtained by other researchers. Fragmentations characteristic of particular functional groups or molecular structures have been summarized. From this data set, guidelines for the interpretation of electron capture negative ion mass spectra have been developed

  14. Electron capture in collisions of S{sup 4+} with helium

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.G.; Stancil, P.C. [Department of Physics and Astronomy and Center for Simulational Physics, University of Georgia, Athens, GA (United States)]. E-mails: wangjg@physast.uga.edu; stancil@physast.uga.edu; Turner, A.R.; Cooper, D.L. [Department of Chemistry, University of Liverpool (United Kingdom)]. E-mail: dlc@liv.ac.uk; Schultz, D.R.; Rakovic, M.J. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)]. E-mails: schultzd@ornl.gov; milun@mail.phy.ornl.gov; Fritsch, W. [Abteilung Theoretische Physik, Hahn-Meitner-Institut Berlin, Berlin (Germany)]. E-mail: fritsch@hmi.de; Zygelman, B. [Department of Physics, University of Nevada, Las Vegas, NV (United States)]. E-mail: bernard@physics.unlv.edu

    2002-07-28

    Charge transfer due to collisions of ground-state S{sup 4+}(3s{sup 2} {sup 1}S) ions with helium is investigated for energies between 0.1 meV u{sup -1} and 10 MeV u{sup -1}. Total and state-selective single electron capture (SEC) cross sections and rate coefficients are obtained utilizing the quantum mechanical molecular-orbital close-coupling (MOCC), atomic-orbital close-coupling (AOCC), classical trajectory Monte Carlo (CTMC) and continuum distorted wave methods. The MOCC calculations utilize ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained with the spin-coupled valence-bond approach. Previous data are limited to a calculation of the total SEC rate coefficient using the Landau-Zener model that is, in comparison to the results presented here, three orders of magnitude smaller. The MOCC SEC cross sections at low energy reveal a multichannel interference effect. True double capture is also investigated with the AOCC and CTMC approaches while autoionizing double capture and transfer ionization (TI) is explored with CTMC. SEC is found to be the dominant process except for E>200 keV u{sup -1} when TI becomes the primary capture channel. Astrophysical implications are briefly discussed. (author)

  15. Annihilation probability density and other applications of the Schwinger multichannel method to the positron and electron scattering

    International Nuclear Information System (INIS)

    Varella, Marcio Teixeira do Nascimento

    2001-12-01

    We have calculated annihilation probability densities (APD) for positron collisions against He atom and H 2 molecule. It was found that direct annihilation prevails at low energies, while annihilation following virtual positronium (Ps) formation is the dominant mechanism at higher energies. In room-temperature collisions (10 -2 eV) the APD spread over a considerable extension, being quite similar to the electronic densities of the targets. The capture of the positron in an electronic Feshbach resonance strongly enhanced the annihilation rate in e + -H 2 collisions. We also discuss strategies to improve the calculation of the annihilation parameter (Z eff ), after debugging the computational codes of the Schwinger Multichannel Method (SMC). Finally, we consider the inclusion of the Ps formation channel in the SMC and show that effective configurations (pseudo eigenstates of the Hamiltonian of the collision ) are able to significantly reduce the computational effort in positron scattering calculations. Cross sections for electron scattering by polyatomic molecules were obtained in three different approximations: static-exchange (SE); tatic-exchange-plus-polarization (SEP); and multichannel coupling. The calculations for polar targets were improved through the rotational resolution of scattering amplitudes in which the SMC was combined with the first Born approximation (FBA). In general, elastic cross sections (SE and SEP approximations) showed good agreement with available experimental data for several targets. Multichannel calculations for e - -H 2 O scattering, on the other hand, presented spurious structures at the electronic excitation thresholds (author)

  16. Compound hypernucleus interpretation of the Λ4H formation probabilities in the stopped K- absorption

    International Nuclear Information System (INIS)

    Tamura, H.; Yamazaki, T.; Sano, M.; Yamamoto, Y.; Wakai, M.; Bando, H.

    1988-06-01

    For the abundant Λ 4 H production observed in the stopped K - absorption on light nuclei, a theoretical model is proposed, in which the basic ingredient is formation and fragmentation of a Λ compound nucleus. The estimated Λ 4 H formation probabilities per stopped K - are in rather good agreement with the observed values. (author)

  17. Studies of collision mechanisms in electron capture by slow multiply charged ions

    International Nuclear Information System (INIS)

    Gilbody, H B; McCullough, R W

    2004-01-01

    We review measurements based on translational energy spectroscopy which are being used to identify and assess the relative importance of the various collision mechanisms involved in one-electron capture by slow multiply charged ions in collisions with simple atoms and molecules

  18. Neutrino Signals in Electron-Capture Storage-Ring Experiments

    Directory of Open Access Journals (Sweden)

    Avraham Gal

    2016-06-01

    Full Text Available Neutrino signals in electron-capture decays of hydrogen-like parent ions P in storage-ring experiments at GSI are reconsidered, with special emphasis placed on the storage-ring quasi-circular motion of the daughter ions D in two-body decays P → D + ν e . It is argued that, to the extent that daughter ions are detected, these detection rates might exhibit modulations with periods of order seconds, similar to those reported in the GSI storage-ring experiments for two-body decay rates. New dedicated experiments in storage rings, or using traps, could explore these modulations.

  19. Study of the radiolysis of tetracycline hydrochloride in powder form, in aqueous solutions and in benzyl alcohol, at 77K, by electron paramagnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Guedes, S.M.L.

    1984-01-01

    The radiolysis of tetracycline hydrochloride in powder form, dissolved in benzyl alcohol and in acid, neutral and alkaline aerated aqueous solutions at 77K is studied by electron paramagnetic resonance spectroscopy. Mechanisms of reactions that occur in the radiolysis of these systems are proposed and some aspects of the reactions that occurs with electrons and with hydrogen atoms at 77K are investigated, since tetracycline hydrochloride captures both paramagnetic species. Also discussed is the influence of some factors in the migration of these species at 77K, such as: the position of solutes, the crystalline structure of the solvent, the kinetic energy of the species and the angle of incidence in the channeling. The rate constants for the reaction between the electron and physical and chemical traps which are present in the alkaline aerated aqueous solutions, at 77k, are calculated. The values found are, respectively: k=9.6 x 10 15 1 mol -1 s -1 and k= 1.8 x 10 10 1 mol -1 s -1 . (Author) [pt

  20. Probable interaction between an oral vitamin K antagonist and turmeric (Curcuma longa).

    Science.gov (United States)

    Daveluy, Amélie; Géniaux, Hélène; Thibaud, Lucile; Mallaret, Michel; Miremont-Salamé, Ghada; Haramburu, Françoise

    2014-01-01

    We report a probable interaction between a vitamin K antagonist, fluindione, and the herbal medicine turmeric that resulted in the elevation of the international normalized ratio (INR). The case presented here underlines the importance of considering potential exposure to herbal medications when assessing adverse effects. © 2014 Société Française de Pharmacologie et de Thérapeutique.

  1. An electron-microscopical analysis of capture and initial stages of penetration of nematodes by Arthrobotrys oligospora

    NARCIS (Netherlands)

    Veenhuis, Marten; Nordbring-Hertz, Birgit; Harder, Wim

    1985-01-01

    A detailed analysis was made of the capture and subsequent penetration of nematodes by the nematophagous fungus Arthrobotrys oligospora using different electron-microscopical techniques. Capture of nematodes by this fungus occurred on complex hyphal structures (traps) and was effectuated by an

  2. Differential Single-Capture Cross Sections for Fast Alpha–Helium Collisions

    International Nuclear Information System (INIS)

    Ghanbari-Adivi, Ebrahim; Ghavaminia, Hoda

    2014-01-01

    A four-body theoretical study of the single charge transfer process in collision of energetic alpha ions with helium atoms in their ground states is presented. The model utilizes the Coulomb–Born distorted wave approximation with correct boundary conditions to calculate the single-electron capture differential and integral cross sections. The influence of the dynamic and static electron correlations on the capture probability is investigated. The results of the calculations are compared with the recent experimental measurements for differential cross sections and with the other theoretical manipulations. The results for scattering at extreme forward angles are in good agreement with the experimental measurements, but in other scattering angles the agreement is poor. However, the present four-body results for integral cross sections are in excellent agreement with the experimental data. (author)

  3. Pair production with electron capture in peripheral collisions of relativistic heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Bertulani, C.A.C.A. E-mail: bertu@if.ufrj.br; Dolci, D.D. E-mail: dolci@if.ufrj.br

    2001-02-26

    The production of electron-positron pairs with the capture of the electron in an atomic orbital is investigated for the conditions of the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). Dirac wave functions for the leptons are used, taking corrections to orders of Z{alpha} into account. The dependence on the transverse momentum transfer is studied and the accuracy of the equivalent photon approximation is discussed as a function of the nuclear charge.

  4. Electron Capture Dissociation of Weakly Bound Polypeptide Polycationic Complexes

    DEFF Research Database (Denmark)

    Haselmann, Kim F; Jørgensen, Thomas J D; Budnik, Bogdan A

    2002-01-01

    as well as specific complexes of modified glycopeptide antibiotics with their target peptide. The weak nature of bonding is substantiated by blackbody infrared dissociation, low-energy collisional excitation and force-field simulations. The results are consistent with a non-ergodic ECD cleavage mechanism.......We have previously reported that, in electron capture dissociation (ECD), rupture of strong intramolecular bonds in weakly bound supramolecular aggregates can proceed without dissociation of weak intermolecular bonds. This is now illustrated on a series of non-specific peptide-peptide dimers...

  5. Exact Time-Dependent Exchange-Correlation Potential in Electron Scattering Processes

    Science.gov (United States)

    Suzuki, Yasumitsu; Lacombe, Lionel; Watanabe, Kazuyuki; Maitra, Neepa T.

    2017-12-01

    We identify peak and valley structures in the exact exchange-correlation potential of time-dependent density functional theory that are crucial for time-resolved electron scattering in a model one-dimensional system. These structures are completely missed by adiabatic approximations that, consequently, significantly underestimate the scattering probability. A recently proposed nonadiabatic approximation is shown to correctly capture the approach of the electron to the target when the initial Kohn-Sham state is chosen judiciously, and it is more accurate than standard adiabatic functionals but ultimately fails to accurately capture reflection. These results may explain the underestimation of scattering probabilities in some recent studies on molecules and surfaces.

  6. Electronic data capture and DICOM data management in multi-center clinical trials

    Science.gov (United States)

    Haak, Daniel; Page, Charles-E.; Deserno, Thomas M.

    2016-03-01

    Providing eligibility, efficacy and security evaluation by quantitative and qualitative disease findings, medical imaging has become increasingly important in clinical trials. Here, subject's data is today captured in electronic case reports forms (eCRFs), which are offered by electronic data capture (EDC) systems. However, integration of subject's medical image data into eCRFs is insufficiently supported. Neither integration of subject's digital imaging and communications in medicine (DICOM) data, nor communication with picture archiving and communication systems (PACS), is possible. This aggravates the workflow of the study personnel, in special regarding studies with distributed data capture in multiple sites. Hence, in this work, a system architecture is presented, which connects an EDC system, a PACS and a DICOM viewer via the web access to DICOM objects (WADO) protocol. The architecture is implemented using the open source tools OpenClinica, DCM4CHEE and Weasis. The eCRF forms the primary endpoint for the study personnel, where subject's image data is stored and retrieved. Background communication with the PACS is completely hidden for the users. Data privacy and consistency is ensured by automatic de-identification and re-labelling of DICOM data with context information (e.g. study and subject identifiers), respectively. The system is exemplarily demonstrated in a clinical trial, where computer tomography (CT) data is de-centrally captured from the subjects and centrally read by a chief radiologists to decide on inclusion of the subjects in the trial. Errors, latency and costs in the EDC workflow are reduced, while, a research database is implicitly built up in the background.

  7. Recent progress in nonperturbative electromagnetic lepton-pair production with capture in relativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    Wells, J.C.; Oberacker, V.E.; Umar, A.S.

    1993-01-01

    The prospect of new colliding-beam accelerators capable of producing collisions of highly stripped high-Z ions, at fixed-target energies per nucleon up to 20 TeV or more, has motivated much interest in lepton-pair production from the QED vacuum. The time-dependent and essentially classical electromagnetic fields involved in such collisions contain larger Fourier components which give rise to sizable lepton-pair production in addition to many other exotic particles. The process of electron-positron production with electron capture is a principal beam-loss mechanism for highly charged ions in a storage ring. In this process, the electron is created in a bound state of one of the participant heavy ions (most likely the 1s state), thus changing the ion's charge state and causing it to be deflected out of the beam. There is a long and sometimes controversial history concerning the use of perturbative methods in studying electromagnetic lepton-pair production; however, reliable perturbative calculations have been used as input into design models for the Relativistic Heavy-Ion Collider (RHIC). Applying perturbation theory to these processes at high energies and small impact parameters results in probabilities which violate unitarity, and cross sections which violate the Froissart bound. This evidence, along with the initial nonperturbative studies, suggests that higher-order QED effects will be important for extreme relativistic collisions. Clearly, large nonperturbative effects in electron-pair production with capture would have important implications for RHIC. In this paper, the authors briefly discuss recent progress in nonperturbative studies of the capture problem. In Section 2, they state the Dirac equation for a lepton in the time-dependent external field of a heavy ion which must be solved to compute lepton-capture probabilities. Section 4 surveys results from recent applications of coupled-channel and lattice techniques to the lepton-capture problem

  8. 77 FR 4059 - Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof; Receipt...

    Science.gov (United States)

    2012-01-26

    ... INTERNATIONAL TRADE COMMISSION [DN 2869] Certain Electronic Devices for Capturing and Transmitting... Interest AGENCY: U.S. International Trade Commission. ACTION: Notice. SUMMARY: Notice is hereby given that the U.S. International Trade Commission has received a complaint entitled In Re Certain Electronic...

  9. The β+-electron capture decay of 73Kr

    International Nuclear Information System (INIS)

    Miehe, C.; Dessagne, P.; Pujol, Ch.; Walter, G.; Jonson, B.; Lindroos, M.

    1999-01-01

    The β + - electron capture decay of 73 Kr, produced at the ISOLDE CERN facility, has been studied by β-delayed proton and gamma emission. The established decay scheme involves 15 up to now unreported gamma emitting levels in 73 Br. The total proton branching ratio has been measured to be 0.0025±0.0003. From this work, a spin and parity 3/2 - is assigned to the 73 Kr ground state, on the basis of the allowed β branch to the 73 Br J π =1/2 - ground state and the feeding of the 5/2 + level located at 286 keV in 73 Br. (orig.)

  10. Single-electron capture into Ar+ excited states in Ar2 + Na collision below 12 keV, 1

    International Nuclear Information System (INIS)

    Matsumoto, Atsushi; Tsurubuchi, Seiji; Okuno, Kazuhiko; Ohtani, Shunsuke; Iwai, Tsuruji.

    1979-08-01

    Emission spectra between 2800 and 6000 A have been observed at the ionic energies from 0.2 to 12 keV. Absolute measurements of emission cross-sections have been made for the emission lines coming from ArII excited states at 4 and 8 keV with a crossed-beam technique. Processes of single-electron capture into the ArII 4p- and 4p'-states, with exothermicity of a few eV, take place dominantly (--10 15 cm 2 ), while the endothermic processes producing ArII in the 4d- and 5s-states occur with small cross-sections. Sum of the cross-sections for electron capture into the excited states observed is comparable with the total single-electron capture cross-section estimated from attenuation measurements of ion currents. Possible errors and uncertainties are discussed. (author)

  11. Single-electron capture into Ar+ excited states in Ar2++Na collision below 12 keV, 1

    International Nuclear Information System (INIS)

    Matsumoto, Atsushi; Tsurubuchi, Seiji; Iwai, Tsuruji; Ohtani, Shunsuke; Okuno, Kazuhiko

    1980-01-01

    Emission spectra between 2800 and 6000 A have been observed at the ionic energies from 0.2 to 12 keV. Absolute measurements of emission cross-sections have been made for the emission lines coming from ArII excited states at 4 and 8 keV with a crossed-beam technique. Processes of single-electron capture into the ArII 4p- and 4p'-states, with exothermicity of a few eV, take place dominantly (--10 -15 cm 2 ), while the endothermic processes producing ArII in the 4d- and 5s-states occur with small cross-sections. Sum of the cross-sections for electron capture into the excited states observed is comparable with the total single-electron capture cross-section estimated from attenuation measurements of ion currents. Possible errors and uncertainties are discussed. (author)

  12. Production of 147Eu for gamma-ray emission probability measurement

    International Nuclear Information System (INIS)

    Katoh, Keiji; Marnada, Nada; Miyahara, Hiroshi

    2002-01-01

    Gamma-ray emission probability is one of the most important decay parameters of radionuclide and many researchers are paying efforts to improve the certainty of it. The certainties of γ-ray emission probabilities for neutron-rich nuclides are being improved little by little, but the improvements of those for proton-rich nuclides are still insufficient. Europium-147 that decays by electron capture or β + -particle emission is a proton-rich nuclide and the γ-ray emission probabilities evaluated by Mateosian and Peker have large uncertainties. They referred to only one report concerning with γ-ray emission probabilities. Our final purpose is to determine the precise γ-ray emission probabilities of 147 Eu from disintegration rates and γ-ray intensities by using a 4πβ-γ coincidence apparatus. Impurity nuclides affect largely to the determination of disintegration rate; therefore, a highly pure 147 Eu source is required. This short note will describe the most proper energy for 147 Eu production through 147 Sm(p, n) reaction. (author)

  13. Application of a distorted wave model to electron capture in atomic collisions

    International Nuclear Information System (INIS)

    Deco, G.R.; Martinez, A.E.; Rivarola, R.D.

    1988-01-01

    In this work, it is presented the CDW-EIS approximation applied to the description of processes of electron capture in ion-atom collisions. Differential and total cross sections are compared to results obtained by other theoretical models, as well as, to experimental data. (A.C.A.S.) [pt

  14. Monitoring compliance with transfusion guidelines in hospital departments by electronic data capture

    DEFF Research Database (Denmark)

    Norgaard, Astrid; De Lichtenberg, Trine Honnens; Nielsen, Jens

    2014-01-01

    -transfusion haemoglobin levels at the departmental level. In a tertiary care hospital, no such data were produced before this study. Our aim was to establish a Patient Blood Management database based on electronic data capture in order to monitor compliance with transfusion guidelines at departmental and hospital levels...

  15. New measurement of neutron capture resonances of 209Bi

    CERN Document Server

    Domingo-Pardo, C.; Aerts, G.; Alvarez-Pol, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.; Badurek, G.; Baumann, P.; Becvar, F.; Berthoumieux, E.; Calvino, F.; Cano-Ott, D.; Capote, R.; Carrillode Albornoz, A.; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Couture, A.; Cox, J.; Dahlfors, M.; David, S.; Dillman, I.; Dolfini, R.; Dridi, W.; Duran, I.; Eleftheriadis, C.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; Fitzpatrick, L.; Frais-Koelbl, H.; Fujii, K.; Furman, W.; Gallino, R.; Goncalves, I.; Gonzalez-Romero, E.; Goverdovski, A.; Gramegna, F.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Igashira, M.; Isaev, S.; Jericha, E.; Kadi, Y.; Kappeler, F.; Karamanis, D.; Karadimos, D.; Kerveno, M.; Ketlerov, V.; Koehler, P.; Konovalov, V.; Kossionides, E.; Krticka, M.; Lamboudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marques, L.; Marrone, S.; Mastinu, P.; Mengoni, A.; Milazzo, P.M.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; Oshima, M.; O'Brien, S.; Pancin, J.; Papachristodoulou, C.; 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.; Stephan, C.; Tagliente, G.; Tain, J.L.; Tassan-Got, L.; Tavora, L.; Terlizzi, R.; Vannini, G.; Vaz, P.; Ventura, Alberto; Villamarin, D.; Vincente, M.C.; Vlachoudis, V.; Vlastou, R.; Voss, F.; Walter, S.; Wendler, H.; Wiescher, M.; Wisshak, K.

    2006-01-01

    The neutron capture cross section of Bi209 has been measured at the CERN n TOF facility by employing the pulse-height-weighting technique. Improvements over previous measurements are mainly because of an optimized detection system, which led to a practically negligible neutron sensitivity. Additional experimental sources of systematic error, such as the electronic threshold in the detectors, summing of gamma-rays, internal electron conversion, and the isomeric state in bismuth, have been taken into account. Gamma-ray absorption effects inside the sample have been corrected by employing a nonpolynomial weighting function. Because Bi209 is the last stable isotope in the reaction path of the stellar s-process, the Maxwellian averaged capture cross section is important for the recycling of the reaction flow by alpha-decays. In the relevant stellar range of thermal energies between kT=5 and 8 keV our new capture rate is about 16% higher than the presently accepted value used for nucleosynthesis calculations. At th...

  16. Removal of nonorthogonality in the Born theory used for study of electron capture in high energy ion-atom collisions

    International Nuclear Information System (INIS)

    Kimura, M.

    1989-01-01

    We show the complete removal of the nonorthogonality of wave functions between initial and final states in the Born theory. Hence, this treatment offers more realistic electron capture cross sections in high energy ion-atom collisions. Representative results for resonant electron capture in H + + H collision are discussed in conjunction with other perturbative results. 10 refs., 1 fig

  17. Electron capture in collisions of Si3+ ions with atomic hydrogen from low to intermediate energies

    Science.gov (United States)

    Liu, C. H.; Liu, L.; Wang, J. G.

    2014-07-01

    The electron capture process for the Si3+(3s) + H(1s) collisions is investigated by the quantum-mechanical molecular orbital close-coupling (MOCC) method and by the two-center atomic orbital close-coupling (AOCC) method in the energy range of 10-5-10 keV/u and 0.8-200 keV/u, respectively. Total and state-selective cross sections are presented and compared with the available theoretical and experimental results. The present MOCC and AOCC results agree well with the experimental measurements, but show some discrepancy with the calculations of Wang et al. [Phys. Rev. A 74, 052709 (2006), 10.1103/PhysRevA.74.052709] at E > 40 eV/u because of the inclusion of rotational couplings, which play important roles in the electron capture process. At lower energies, the present results are about three to five times smaller than those of Wang et al. due to the difference in the molecular data at large internuclear distances. The energy behaviors of the electron capture cross sections are discussed on the basis of identified reaction mechanisms.

  18. Electron-trapping probability in natural dosemeters as a function of irradiation temperature

    DEFF Research Database (Denmark)

    Wallinga, J.; Murray, A.S.; Wintle, A.G.

    2002-01-01

    The electron-trapping probability in OSL traps as a function of irradiation temperature is investigated for sedimentary quartz and feldspar. A dependency was found for both minerals; this phenomenon could give rise to errors in dose estimation when the irradiation temperature used in laboratory...... procedures is different from that in the natural environment. No evidence was found for the existence of shallow trap saturation effects that Could give rise to a dose-rate dependency of electron trapping....

  19. Experimental impact-parameter--dependent probabilities for K-shell vacancy production by fast heavy-ion projectiles

    International Nuclear Information System (INIS)

    Randall, R.R.; Bednar, J.A.; Curnutte, B.; Cocke, C.L.

    1976-01-01

    The impact-parameter dependence of the probability for production of target K x rays has been measured for oxygen projectiles on copper and for carbon and fluorine projectiles on argon at scaled velocities near 0.5. The O-on-Cu data were taken for 1.56-, 1.88-, and 2.69-MeV/amu O beams incident upon thin Cu foils. A thin Ar-gas target was used for 1.56-MeV/amu C and F beams, permitting measurements to be made for charge-pure C +4 , C +6 , F +9 and F +5 projectiles. Ar and Cu K x rays were observed with a Si(Li) detector and scattered projectiles with a collimated surface-barrier detector. Comparison of the shapes of the measured K-vacancy--production probability curves with predictions of the semiclassical Coulomb approximation (SCA) shows adequate agreement for the O-on-Cu system. For the higher ratio of projectile-to-target nuclear charge (Z 1 /Z 2 ) characterizing the C-on-Ar and F-on-Ar systems, the SCA predictions are entirely inadequate in describing the observed impact-parameter dependence. In particular, they cannot account for large probabilities found at large impact parameters. Furthermore, the dependence of the shapes on the projectile charge state is found to become pronounced at larger Z 1 /Z 2 . Attempts to account for this behavior in terms of alternative vacancy-production processes are discussed

  20. Ultra low-K shrinkage behavior when under electron beam in a scanning electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Lorut, F.; Imbert, G. [ST Microelectronics, 850 rue Jean Monnet, 38926 Crolles Cedex (France); Roggero, A. [Centre National d' Etudes Spatiales, 18 Avenue Edouard Belin, 31400 Toulouse (France)

    2013-08-28

    In this paper, we investigate the tendency of porous low-K dielectrics (also named Ultra Low-K, ULK) behavior to shrink when exposed to the electron beam of a scanning electron microscope. Various experimental electron beam conditions have been used for irradiating ULK thin films, and the resulting shrinkage has been measured through use of an atomic force microscope tool. We report the shrinkage to be a fast, cumulative, and dose dependent effect. Correlation of the shrinkage with incident electron beam energy loss has also been evidenced. The chemical modification of the ULK films within the interaction volume has been demonstrated, with a densification of the layer and a loss of carbon and hydrogen elements being observed.

  1. Identification and measurement of chlorinated organic pesticides in water by electron-capture gas chromatography

    Science.gov (United States)

    Lamar, William L.; Goerlitz, Donald F.; Law, LeRoy M.

    1965-01-01

    Pesticides, in minute quantities, may affect the regimen of streams, and because they may concentrate in sediments, aquatic organisms, and edible aquatic foods, their detection and their measurement in the parts-per-trillion range are considered essential. In 1964 the U.S. Geological Survey at Menlo Park, Calif., began research on methods for monitoring pesticides in water. Two systems were selected--electron-capture gas chromatography and microcoulometric-titration gas chromatography. Studies on these systems are now in progress. This report provides current information on the development and application of an electron-capture gas chromatographic procedure. This method is a convenient and extremely sensitive procedure for the detection and measurement of organic pesticides having high electron affinities, notably the chlorinated organic pesticides. The electron-affinity detector is extremely sensitive to these substances but it is not as sensitive to many other compounds. By this method, the chlorinated organic pesticide may be determined on a sample of convenient size in concentrations as low as the parts-per-trillion range. To insure greater accuracy in the identifications, the pesticides reported were separated and identified by their retention times on two different types of gas chromatographic columns.

  2. Single electron capture in ion-atom collisions involving multielectronic targets

    International Nuclear Information System (INIS)

    Abufager, P.N.; Martinez, A.E.; Rivarola, R.D.; Fainstein, P.D.

    2005-01-01

    The generalized continuum distorted wave-eikonal initial state (GCDW-EIS) approximation is employed to study single electron capture by impact of protons on Ne and Ar targets. We analyze the contributions to the total cross sections coming from the different target shells. Present results are compared with theoretical calculations obtained using the previous CDW-EIS formulation and to experimental data in order to show the importance of the description of the bound and continuum target states in the entry and exit channels, respectively

  3. Calculation of the electron trajectory for 200 kV self-shielded electron accelerator

    International Nuclear Information System (INIS)

    Wang Shuiqing

    2000-01-01

    In order to calculate the electron trajectory of 200 kV self-shielded electron accelerator, the electric field is calculated with a TRAJ program. In this program, following electron track mash points one by one, the electron beam trajectories are calculated. Knowing the effect of grid voltage on electron optics and gaining grid voltage focusing effect in the various energy grades, the authors have gained scientific basis for adjusting grid voltage, and also accumulated a wealth of experience for designing self-shielded electron accelerator or electron curtain in future

  4. High temperature CO2 capture of hydroxyapatite extracted from tilapia scales

    Directory of Open Access Journals (Sweden)

    Oscar H. Ojeda-Niño

    2017-11-01

    Full Text Available Hydroxyapatite (HAp was obtained from tilapia scales by two extraction methods: direct calcination and acid-base treatment. The physicochemical characteristics of the obtained HAps were evaluated by thermogravimetric analysis, X-ray fluorescence, X-ray diffraction, scanning electron microscopy, surface area, infrared spectroscopy, and basicity measurement at 298 K by CO2-pulse titration. Furthermore, the CO2 capture capacity of the solids at high temperature was also determined. Both methods showed the presence of a HAp phase although significant differences in the properties of the solids were found. The HAp obtained by direct calcination exhibited a lower crystallinity and a greater surface area and basicity than the HAp obtained by the acid-base treatment. These features were correlated with the solid’s CO2 capture capacity. In this work, CO2 capture capacity values for HAp yielded by calcination ranged from 2.5 to 3.2 mg CO2 /g captured at 973 K, and for the acid-base treatment-derived HAp, CO2 capture capacity values between 1.2 to 2.5 mg CO2 /g were recorded. These results reveal the potential of HAps extracted from tilapia scales as solids with high CO2 capture capacity, thermal stability, and capture/release cycles reversibility.

  5. Electron cyclotron emission measurements at the stellarator TJ-K

    Energy Technology Data Exchange (ETDEWEB)

    Sichardt, Gabriel; Ramisch, Mirko [Institut fuer Grenzflaechenverfahrenstechnik und Plasmatechnologie, Universitaet Stuttgart (Germany); Koehn, Alf [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)

    2016-07-01

    Electron temperature (T{sub e}) measurements in the magnetised plasmas of the stellarator TJ-K are currently performed by means of Langmuir probes. The use of these probes is restricted to relatively low temperatures and the measurement of temperature profiles requires the acquisition of the local current-voltage characteristics which limits strongly the sampling rate. As an alternative, T{sub e} can be measured using the electron cyclotron emission (ECE) that is generated by the gyration of electrons in magnetised plasmas. Magnetic field gradients in the plasma lead to a spatial distribution of emission frequencies and thus the measured intensity at a given frequency can be related to its point of origin. The T{sub e} dependence of the intensity then leads to a temperature profile along the line of sight for Maxwellian velocity distributions. A diagnostic system for T{sub e} measurements using ECE is currently being set up at TJ-K. When non-thermal electrons are present the emission spectrum changes dramatically. Therefore, the ECE can also be used to investigate the contribution of fast electrons to previously observed toroidal net currents in TJ-K. Simulations are used to examine the role of electron drift orbits in generating these currents.

  6. Characterisation of 100 kW electron beam melting gun and its adaptation as electron gun for high power DC electron accelerators

    International Nuclear Information System (INIS)

    Banerjee, Srutarshi; Bhattacharjee, Dhruva; Waghmare, Abhay; Tiwari, Rajnish; Bakhtsingh, R.I.; Dasgupta, K.; Gupta, Sachin; Prakash, Baibhaw; Jha, M.N.

    2015-01-01

    The paper deals with the characterization of the 100 kW electron beam melting gun for its adaptation in high power DC Electron Accelerators. The indigenously designed electron beam melting system at BARC is chosen for characterization. It comprises of electron gun as source of electrons, two electromagnetic focusing lenses viz. upper focusing lens and lower focusing lens for beam focusing, intermediate beam aperture for vacuum decoupling between gun region and melt zone, deflection and oscillation lens for maneuvering the beam on the melt charge and water cooled crucible that acts as a beam dump. In this system, the electron gun is designed for 40 kV and 100 kW corresponding to a maximum beam current of 2.5 A. The electron gun uses directly heated spiral tungsten filament. The operating temperature of the filament is 2800 °K. The focusing electrode and the anode profile are designed based on Pierce geometry. High Power DC Electron Accelerators require high currents of 1 A. The beam must comply with the requirement of 40 mm beam diameter and 10 mrad divergence at the exit of the electron gun. The characterization of the existing electron gun was done to find out all the beam parameters, for e.g. beam size, beam divergence, perveance etc. to be adapted or to be modified for the design of electron gun for high power DC accelerators. This paper shows limitations and the possible solutions for design of high power DC accelerators. (author)

  7. Electron Capture in Slow Collision of He^2++H : Revisited

    Science.gov (United States)

    Krstic, Ps

    2003-05-01

    Very early experimental data (Fite et al. al., Proc. R. Soc. A 268, 527 (1962)) for He^2++H, recent ORNL measurements for Ne^2+ + H and our theoretical estimates suggest that the electron capture cross sections for these strongly exoergic collision systems drop slower toward low collision energies than expected from previous theories. We perform a theoretical study to establish and understand the true nature of this controversy. The calculations are based on the Hidden Crossings MOCC method, augmented with rotational and turning point effects.

  8. Measurement of the Mis-identification Probability of τ Leptons from Hadronic Jets and from Electrons

    CERN Document Server

    The ATLAS collaboration

    2011-01-01

    Measurements of the mis-identification probability of QCD jets and electrons as hadronically decaying τ leptons using tag-and-probe methods are described. The analyses are based on 35pb−1 of proton-proton collision data, taken by the ATLAS experiment at a center-of-mass energy of sqrt(s) = 7 TeV. The mis-identification probabilities range between 10% and 0.1% for QCD jets, and about (1 − 2)% for electrons. They depend on the identification algorithm chosen, the pT and the number of prongs of the τ candidate, and on the amount of pile up present in the event.

  9. Continuum capture in the three-body problem

    International Nuclear Information System (INIS)

    Sellin, I.A.

    1980-01-01

    The three-body problem, especially the problem of electron capture to the continuum in heavy particle collisions is reviewed. Major topics covered include: second born-induced asymmetry in electron capture to the continuum; historical context, links to other tests of atomic scattering theory; experiments characterizing the velocity distribution of ECC electrons; other atomic physics tests of high velocity Born expansions; atom capture; capture by positrons; and pion capture to the continuum

  10. Correlated charge changing interactions and K x-ray emission in ion-atom collisions. Progress report, August 15, 1983-March 15, 1984

    International Nuclear Information System (INIS)

    Bernstein, E.M.; Tanis, J.A.

    1984-03-01

    Correlations between K x-ray emission and charge-changing interactions have been investigated for highly charged vanadium and sulfur ions incident on gas targets under single collision conditions. From measurements of K x-rays coincident with single electron capture, significant new evidence was obtained for the existence of resonant-transfer-and-excitation (RTE) in 180 to 460 MeV V 19+ 20+ 21+ + He collisions and 70 to 160 MeV S 13+ + He collisions. The RTE process, which proceeds via an inverse Auger transition, is qualitatively analogous to dielectronic recombination. For both vanadium and sulfur, the cross section for coincidences between K x rays and capture showed strong resonant behavior. Of particular significance is the observation that for V + He all three charge states exhibited two maxima in the coincidence cross section. Calculations show that these maxima are correlated to intermediate states in the RTE process for which the excited and captured electrons have principal quantum numbers n = 2,2 and n = 2, greater than or equal to 3, respectively. In these same experiments, coincidences between K x-rays and ions which lose an electron were also measured, as well as cross sections for total K x-ray production and total electron capture and loss

  11. Single-electron capture for 2-8 keV incident energy and direct scattering at 6 keV in He2+-He collisions

    International Nuclear Information System (INIS)

    Bordenave-Montesquieu, D.; Dagnac, R.

    1992-01-01

    We studied the single-electron capture as well as the direct processes occurring when a He 2+ ion is scattered by a He target. Doubly differential cross sections were measured for single-electron capture with a collision energy ranging from 2 to 8 keV and a scattering angle varying from 10' to 3 o 30' (laboratory frame). Single-electron capture into excited states of He + was found to be the dominant process, confirming a previous experimental study. Elastic scattering and ionization differential cross sections were measured for E = 6 keV. (Author)

  12. K-shell-hole production, multiple-hole production, charge transfer, and antisymmetry

    International Nuclear Information System (INIS)

    Reading, J.F.; Ford, A.L.

    1980-01-01

    In calculating K-shell-hole production when an ion collides with an atom, account must be taken of the fact that processes involving electrons other than the K-shell electron can occur. For example, after making a K-shell hole an L-shell electron may be knocked into it, or an L-shell vacancy may be produced and the K-shell electron promoted to that vacancy in the ''Fermi sea'' of the target-atom orbitals. In 1973 a theorem was proved by one of the present authors demonstrating that all these multielectron processes cancel in an independent-particle model for the target atom. In this paper it is shown that the same thing occurs for hole production by charge transfer to the ion. The authors demonstrate that multihole production does not obey this simple rule and that the probability for multihole production is not the product of independent single-electron probabilities. The correct expressions that should be used for these processes are given, together with new results for charge-transfer processes accompanied by hole production

  13. Studies of electron correlation effects in multicharged ion atom collisions involving double capture

    International Nuclear Information System (INIS)

    Stolterfoht, N.; Sommer, K.; Griffin, D.C.; Havener, C.C.; Huq, M.S.; Phaneuf, R.A.; Swenson, J.K.; Meyer, F.W.

    1988-01-01

    We review measurements of L-Coster Kronig and Auger electron production in slow, multicharged collision systems to study electron correlation effects in the process of double electron capture. The n/sup /minus/3/ law was confirmed for the production of the Coster-Kronig configurations 1s 2 2pn/ell/ (n ≥ 6) in O 6+ + He collisions. Enhancement of high angular momentum /ell/ in specific 1s 2 2pn/ell/ configurations was observed by means of high-resolution measurements of the Coster-Kronig lines. The importance of electron correlation effects in couplings of potential energy curves leading to the 1s 2 2pn/ell/ configurations is verified by means of Landau-Zener model calculations. 32 refs., 4 figs

  14. ELECTRON-CAPTURE FROM LI BY B-5+, N-5+ AND BE-4+ IONS

    NARCIS (Netherlands)

    HOEKSTRA, R; OLSON, RE; FOLKERTS, HO; WOLFRUM, E; PASCALE, J; DEHEER, FJ; MORGENSTERN, R; WINTER, H

    1993-01-01

    We present state selective experimental and theoretical results for electron capture in B-5+ and N5+-Li collisons at energies in the range of 1-10 keV amu-1. Experimentally we have used photon emission spectroscopy in the VUV and visible spectral range and theoretically we have performed classical

  15. Effect of field-dependent mobility on the escape probability. I. Electrons photoinjected in neopentane

    International Nuclear Information System (INIS)

    Mozumder, A.; Carmichael, I.

    1978-01-01

    A general procedure is described for calculating the escape probability of an electron against neutralization in the presence of an external field after it has been ejected into a dielectric liquid from a planar surface. The present paper utilizes the field-dependent electron mobility measurement in neopentane by Bakale and Schmidt. The calculated escape probability, upon averaging over the initial distribution, is compared with the current efficiency measurement of Holroyd et al. The median thermalization legnth, inferred from this comparison, depends in general upon the assumed form of initial distribution. It is less than the value obtained when the field dependence of the mobility is ignored but greater than that applicable to the high energy irradiation case. A plausible explanation is offered

  16. Electron capture in slow collisions of multicharged ions with hydrogen atoms using merged beams

    International Nuclear Information System (INIS)

    Havener, C.C.; Nesnidal, M.P.; Porter, M.R.; Phaneuf, R.A.

    1991-01-01

    Absolute total electron-capture cross-section mesurements are reported for collisions of O 3+ and O 4+ with atomic hydrogen in the energy range 1-1000 eV /amu using merged beams. The data are compared with available coupled-states theoretical calculations. (orig.)

  17. Hydrogen/deuterium exchange mass spectrometry with top-down electron capture dissociation for characterizing structural transitions of a 17 kDa protein.

    Science.gov (United States)

    Pan, Jingxi; Han, Jun; Borchers, Christoph H; Konermann, Lars

    2009-09-09

    Amide H/D exchange (HDX) mass spectrometry (MS) is widely used for protein structural studies. Traditionally, this technique involves protein labeling in D(2)O, followed by acid quenching, proteolytic digestion, and analysis of peptide deuteration levels by HPLC/MS. There is great interest in the development of alternative HDX approaches involving the top-down fragmentation of electrosprayed protein ions, instead of relying on enzymatic cleavage and solution-phase separations. A number of recent studies have demonstrated that electron capture dissociation (ECD) results in fragmentation of gaseous protein ions with little or no H/D scrambling. However, the successful application of this approach for in-depth protein conformational studies has not yet been demonstrated. The current work uses horse myoglobin as a model system for assessing the suitability of HDX-MS with top-down ECD for experiments of this kind. It is found that ECD can pinpoint the locations of protected amides with an average resolution of less than two residues for this 17 kDa protein. Native holo-myoglobin (hMb) shows considerable protection from exchange in all of its helices, whereas loops are extensively deuterated. Fraying is observable at some helix termini. Removal of the prosthetic heme group from hMb produces apo-myoglobin (aMb). Both hMb and aMb share virtually the same HDX protection pattern in helices A-E, whereas helix F is unfolded in aMb. In addition, destabilization is evident for some residues close to the beginning of helix G, the end of helix H, and the C-terminus of the protein. The structural changes reported herein are largely consistent with earlier NMR data for sperm whale myoglobin, although small differences between the two systems are evident. Our findings demonstrate that the level of structural information obtainable with top-down ECD for small to medium-sized proteins considerably surpasses that of traditional HDX-MS experiments, while at the same time greatly reducing

  18. Electron capture and loss to continuum states in gases and solids

    International Nuclear Information System (INIS)

    Sellin, I.A.; Laubert, R.

    1981-01-01

    A key feature of our experimental procedure is the easy interchange of short gaseous and thin solid targets at the same physical position, with all apparatus aperture sizes, dimensions, positions, and other experimental details unaltered. It has therefore been possible to cancel most systematic apparatus effects in comparing gaseous and solid target results. By using single ion-atom collision techniques, by using bare and few-electron ions of appreciably higher charge than heretofore, by extending the velocity range of measurement appreciably above that of earlier experiments, and by studying charge-state variation over an appreciably wider range than used previously, we have been able to test experimentally features of continuum electron-capture and -loss theories which have been inaccessible in previous experiments. (orig./TW)

  19. Studies of electron correlation effects in multicharged ion atom collisions involving double capture

    Energy Technology Data Exchange (ETDEWEB)

    Stolterfoht, N.; Sommer, K.; Griffin, D.C.; Havener, C.C.; Huq, M.S.; Phaneuf, R.A.; Swenson, J.K.; Meyer, F.W.

    1988-01-01

    We review measurements of L-Coster Kronig and Auger electron production in slow, multicharged collision systems to study electron correlation effects in the process of double electron capture. The n/sup /minus/3/ law was confirmed for the production of the Coster-Kronig configurations 1s/sup 2/2pn/ell/ (n greater than or equal to 6) in O/sup 6 +/ + He collisions. Enhancement of high angular momentum /ell/ in specific 1s/sup 2/2pn/ell/ configurations was observed by means of high-resolution measurements of the Coster-Kronig lines. The importance of electron correlation effects in couplings of potential energy curves leading to the 1s/sup 2/2pn/ell/ configurations is verified by means of Landau-Zener model calculations. 32 refs., 4 figs.

  20. The calorimetric spectrum of the electron-capture decay of $^{163}$Ho. A preliminary analysis of the preliminary data

    CERN Document Server

    De Rújula, A.

    2015-01-01

    It is in principle possible to measure directly the electron neutrino mass (or masses and mixing angles) in weak electron-capture decays. The optimal nuclide in this respect is $^{163}$Ho. The favoured experimental technique, currently pursued in various experiments (ECHo, HOLMES and NuMECS) is "calorimetric". The calorimetric energy spectrum is a sum over the unstable vacant orbitals, or "holes", left by the electrons weakly captured by the nucleus. We discuss the current progress in this field and analize the preliminary data. Our conclusion is that, as pointed out by Robertson, the contribution of two-hole states is not negligible. But --in strong contradistinction with the tacit conclusion of previous comparisons of theory and observations-- we find a quite satisfactory agreement. A crucial point is that, in the creation of secondary holes, electron shakeoff and not only electron shakeup must be taken into account.

  1. Nonperturbative electromagnetic muon-pair production with capture in peripheral relativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    Wells, J.C.

    1991-01-01

    We discuss preliminary calculations of impact-parameter-dependent probabilities and cross sections for muon-pair production with capture of the negative muon into the K-shell of the target caused by the time-dependent electromagnetic fields generated in peripheral relativistic heavy-ion collisions. Our approach is nonperturbative in that we calculate probabilities by solving the time-dependent Dirac equation on a three-dimensional Cartesian lattice using the basis-spline collocation method. Use of the axial gauge for the electromagnetic potentials produces an interaction easier to implement on the lattice than the Lorentz gauge. 19 refs., 5 figs

  2. Electron capture in collisions between O6+ ions and H2O molecules

    NARCIS (Netherlands)

    Bodewits, D.; Hoekstra, R.

    By means of photon emission spectroscopy, state selective electron capture cross section for low energy (0.1-7.5 keV/amu) collisions of O6+ on H2O molecules have been measured. Over the range of interaction energies the state selective cross sections change strongly, i.e., by factors up to 5, while

  3. Characterization and testing of 30 kV, 60 kW electron optical column for melting applications

    Energy Technology Data Exchange (ETDEWEB)

    Baibhaw, Prakash; Gupta, Sachin; Malik, Pravanjan, E-mail: bprakash@barc.gov.in [Bhabha Atomic Research Centre, Mumbai (India)

    2014-07-01

    High energy electron beams (30-150 keV) are widely used as intense heat source in welding, melting and evaporation of refractory metals. These operations are mostly carried out in high vacuum (10{sup -4}-10{sup -5} mbar) to aid unimpeded flow of electrons from generation to the point of application. A 30 kV, 60 kW Electron beam optical column (EOC) is designed and developed under the high power beam technology programme. The optical column consists of an electron gun and twin electromagnetic focusing lenses. The heating power of emitter, gun perveance, grid voltage control, beam focusing with the twin electromagnetic lenses and beam spot size measurements are reported in this paper. The results are compared with the design values. Operational issues during the high power melting and the strategy for automation of the electron gun are discussed. (author)

  4. Electronic data capture in a rural African setting: evaluating experiences with different systems in Malawi

    OpenAIRE

    King, Carina; Hall, Jenny; Banda, Masford; Beard, James; Bird, Jon; Kazembe, Peter; Fottrell, Ed

    2014-01-01

    Background\\ud \\ud As hardware for electronic data capture (EDC), such as smartphones or tablets, becomes cheaper and more widely available, the potential for using such hardware as data capture tools in routine healthcare and research is increasing.\\ud \\ud Objective\\ud \\ud We aim to highlight the advantages and disadvantages of four EDC systems being used simultaneously in rural Malawi: two for Android devices (CommCare and ODK Collect), one for PALM and Windows OS (Pendragon), and a custom-b...

  5. Electron-capture Isotopes Could Constrain Cosmic-Ray Propagation Models

    Science.gov (United States)

    Benyamin, David; Shaviv, Nir J.; Piran, Tsvi

    2017-12-01

    Electron capture (EC) isotopes are known to provide constraints on the low-energy behavior of cosmic rays (CRs), such as reacceleration. Here, we study the EC isotopes within the framework of the dynamic spiral-arms CR propagation model in which most of the CR sources reside in the galactic spiral arms. The model was previously used to explain the B/C and sub-Fe/Fe ratios. We show that the known inconsistency between the 49Ti/49V and 51V/51Cr ratios remains also in the spiral-arms model. On the other hand, unlike the general wisdom that says the isotope ratios depend primarily on reacceleration, we find here that the ratio also depends on the halo size (Z h) and, in spiral-arms models, also on the time since the last spiral-arm passage ({τ }{arm}). Namely, EC isotopes can, in principle, provide interesting constraints on the diffusion geometry. However, with the present uncertainties in the lab measurements of both the electron attachment rate and the fragmentation cross sections, no meaningful constraint can be placed.

  6. Non-Maxwellian electron energy probability functions in the plume of a SPT-100 Hall thruster

    Science.gov (United States)

    Giono, G.; Gudmundsson, J. T.; Ivchenko, N.; Mazouffre, S.; Dannenmayer, K.; Loubère, D.; Popelier, L.; Merino, M.; Olentšenko, G.

    2018-01-01

    We present measurements of the electron density, the effective electron temperature, the plasma potential, and the electron energy probability function (EEPF) in the plume of a 1.5 kW-class SPT-100 Hall thruster, derived from cylindrical Langmuir probe measurements. The measurements were taken on the plume axis at distances between 550 and 1550 mm from the thruster exit plane, and at different angles from the plume axis at 550 mm for three operating points of the thruster, characterized by different discharge voltages and mass flow rates. The bulk of the electron population can be approximated as a Maxwellian distribution, but the measured distributions were seen to decline faster at higher energy. The measured EEPFs were best modelled with a general EEPF with an exponent α between 1.2 and 1.5, and their axial and angular characteristics were studied for the different operating points of the thruster. As a result, the exponent α from the fitted distribution was seen to be almost constant as a function of the axial distance along the plume, as well as across the angles. However, the exponent α was seen to be affected by the mass flow rate, suggesting a possible relationship with the collision rate, especially close to the thruster exit. The ratio of the specific heats, the γ factor, between the measured plasma parameters was found to be lower than the adiabatic value of 5/3 for each of the thruster settings, indicating the existence of non-trivial kinetic heat fluxes in the near collisionless plume. These results are intended to be used as input and/or testing properties for plume expansion models in further work.

  7. Radiative proton-capture nuclear processes in metallic hydrogen

    International Nuclear Information System (INIS)

    Ichimaru, Setsuo

    2001-01-01

    Protons being the lightest nuclei, metallic hydrogen may exhibit the features of quantum liquids most relevant to enormous enhancement of nuclear reactions; thermonuclear and pycnonuclear rates and associated enhancement factors of radiative proton captures of high-Z nuclei as well as of deuterons are evaluated. Atomic states of high-Z impurities are determined in a way consistent with the equations of state and screening characteristics of the metallic hydrogen. Rates of pycnonuclear p-d reactions are prodigiously high at densities ≥20 g/cm 3 , pressures ≥1 Gbar, and temperatures ≥950 K near the conditions of solidification. It is also predicted that proton captures of nuclei such as C, N, O, and F may take place at considerable rates, owing to strong screening by K-shell electrons, if the densities ≥60-80 g/cm 3 , the pressures ≥7-12 Gbar, and the temperatures just above solidification. The possibilities and significance of pycnonuclear p-d fusion experiments are specifically remarked

  8. 77 FR 11588 - Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof

    Science.gov (United States)

    2012-02-27

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-831] Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof AGENCY: U.S. International Trade Commission... Trade Commission on January 10, 2012, under section 337 of the Tariff Act of 1930, as amended, 19 U.S.C...

  9. Electron capture by C2+ and Ti2+ ions in H and H2

    International Nuclear Information System (INIS)

    Nutt, W.L.; McCullough, R.W.; Gilbody, H.B.

    1978-01-01

    Cross sections for electron capture by C 2+ and Ti 2+ ions in H and H 2 have been determined within the energy range 0.5 to 14 keV from measurements made using a tungsten-tube furnace to provide a target of highly dissociated hydrogen. (author)

  10. Electron spin resonance of gamma, electron, neutron and fission fragments irradiated K2SO4

    International Nuclear Information System (INIS)

    Kamali, J.; Walton, G.N.

    1985-01-01

    The electron spin resonance (ESR) of K 2 SO 4 irradiated by γ, electron, neutron and fission fragments has been investigated. The ESR spectra are attributed mainly to the formation of SO 3 - , SO 4 - , SO 2 - , and O 3 - radical ions. The most intense radical ion observed was due to the SO 3 - , and the other radicals were relatively much lower in intensity. Thermal annealing showed a significant decrease in the concentration of radical ions. The concentration of SO 3 - was measured in γ-irradiated K 2 SO 4 and K 2 SO 4 containing fission fragments. In fission fragments irradiated K 2 SO 4 , the G-value observed for SO 3 - radical formation was about eight times higher than that of γ-irradiated K 2 SO 4 . This was attributed to the high LET (Linear Energy Transfer) of the fission fragments. (author)

  11. Capturing structured, pulmonary disease-specific data elements in electronic health records.

    Science.gov (United States)

    Gronkiewicz, Cynthia; Diamond, Edward J; French, Kim D; Christodouleas, John; Gabriel, Peter E

    2015-04-01

    Electronic health records (EHRs) have the potential to improve health-care quality by allowing providers to make better decisions at the point of care based on electronically aggregated data and by facilitating clinical research. These goals are easier to achieve when key, disease-specific clinical information is documented as structured data elements (SDEs) that computers can understand and process, rather than as free-text/natural-language narrative. This article reviews the benefits of capturing disease-specific SDEs. It highlights several design and implementation considerations, including the impact on efficiency and expressivity of clinical documentation and the importance of adhering to data standards when available. Pulmonary disease-specific examples of collection instruments are provided from two commonly used commercial EHRs. Future developments that can leverage SDEs to improve clinical quality and research are discussed.

  12. Correlation between atomic negative muon capture and electron distribution in organic sp2-hybridization compounds CxHyClz

    International Nuclear Information System (INIS)

    Sakai, Yoichi; Tominaga, Takeshi; Ikuta, Shigeru

    1986-01-01

    The atomic negative muon capture ratios determined experimentally in organic sp 2 -hybridization compound, C x H y Cl z , were compared with the electron populations of carbon atomic orbitals obtained by an ab initio molecular orbital calculation in such systems. A clear positive correlation was found between the C 2s and C 2pz populations and the negative muon capture ratio A (C/Cl), suggesting the mesomolecular process in the initial stage of muon capture. (orig.)

  13. A technique for searching for the 2 K capture in 124Xe with a copper proportional counter

    Science.gov (United States)

    Gavrilyuk, Yu. M.; Gangapshev, A. M.; Kazalov, V. V.; Kuzminov, V. V.; Panasenko, S. I.; Ratkevich, S. S.; Tekueva, D. A.; Yakimenko, S. P.

    2015-12-01

    An experimental technique for searching for the 2 K capture in 124Xe with a large low-background copper proportional counter is described. Such an experiment is conducted at the Baksan Neutrino Observatory of the Institute for Nuclear Research of the Russian Academy of Sciences. The experimental setup is located in the Low-Background Deep-Level Laboratory at a depth of 4900 m.w.e., where the flux of muons of cosmic rays is suppressed by a factor of 107 relative to that at the Earth's surface. The setup incorporates a proportional counter and low-background shielding (18 cm of copper, 15 cm of lead, and 8 cm of borated polyethylene). The results of processing the data obtained in 5 months of live measurement time are presented. A new limit on the half-life of 124Xe with respect to the 2 K capture is set at the level of 2.5 × 1021 years.

  14. Multiple electron processes of He and Ne by proton impact

    Science.gov (United States)

    Terekhin, Pavel Nikolaevich; Montenegro, Pablo; Quinto, Michele; Monti, Juan; Fojon, Omar; Rivarola, Roberto

    2016-05-01

    A detailed investigation of multiple electron processes (single and multiple ionization, single capture, transfer-ionization) of He and Ne is presented for proton impact at intermediate and high collision energies. Exclusive absolute cross sections for these processes have been obtained by calculation of transition probabilities in the independent electron and independent event models as a function of impact parameter in the framework of the continuum distorted wave-eikonal initial state theory. A binomial analysis is employed to calculate exclusive probabilities. The comparison with available theoretical and experimental results shows that exclusive probabilities are needed for a reliable description of the experimental data. The developed approach can be used for obtaining the input database for modeling multiple electron processes of charged particles passing through the matter.

  15. Single-electron capture for 2-8 keV incident energy and direct scattering at 6 keV in He[sup 2+]-He collisions

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, D.; Dagnac, R. (Toulouse-3 Univ., 31 (France). Centre de Physique Atomique)

    1992-06-14

    We studied the single-electron capture as well as the direct processes occurring when a He[sup 2+] ion is scattered by a He target. Doubly differential cross sections were measured for single-electron capture with a collision energy ranging from 2 to 8 keV and a scattering angle varying from 10' to 3[sup o]30' (laboratory frame). Single-electron capture into excited states of He[sup +] was found to be the dominant process, confirming a previous experimental study. Elastic scattering and ionization differential cross sections were measured for E = 6 keV. (Author).

  16. Microfluidic device for cell capture and impedance measurement.

    Science.gov (United States)

    Jang, Ling-Sheng; Wang, Min-How

    2007-10-01

    This work presents a microfluidic device to capture physically single cells within microstructures inside a channel and to measure the impedance of a single HeLa cell (human cervical epithelioid carcinoma) using impedance spectroscopy. The device includes a glass substrate with electrodes and a PDMS channel with micro pillars. The commercial software CFD-ACE+ is used to study the flow of the microstructures in the channel. According to simulation results, the probability of cell capture by three micro pillars is about 10%. An equivalent circuit model of the device is established and fits closely to the experimental results. The circuit can be modeled electrically as cell impedance in parallel with dielectric capacitance and in series with a pair of electrode resistors. The system is operated at low frequency between 1 and 100 kHz. In this study, experiments show that the HeLa cell is successfully captured by the micro pillars and its impedance is measured by impedance spectroscopy. The magnitude of the HeLa cell impedance declines at all operation voltages with frequency because the HeLa cell is capacitive. Additionally, increasing the operation voltage reduces the magnitude of the HeLa cell because a strong electric field may promote the exchange of ions between the cytoplasm and the isotonic solution. Below an operating voltage of 0.9 V, the system impedance response is characteristic of a parallel circuit at under 30 kHz and of a series circuit at between 30 and 100 kHz. The phase of the HeLa cell impedance is characteristic of a series circuit when the operation voltage exceeds 0.8 V because the cell impedance becomes significant.

  17. Correlation effects on double electron capture in highly-charged, low-energy ion-atom collisions

    International Nuclear Information System (INIS)

    Meyer, F.W.; Griffin, D.C.; Havener, C.C.; Huq, M.S.; Phaneuf, R.A.; Swenson, J.K.; Stolterfoht, N.

    1987-01-01

    The method of zero-degree Auger electron spectroscopy has been used to study two-electron excited states populated in slow double capture collisions of highly charged ions with He and H 2 . The focus of this study is on production of autoionization electrons originating from the non-equivalent 1s 2 2pnl electron configurations in comparison with electron production resulting from the Auger decay of (near) equivalent 1s 2 nln'l' (with n∼n') configurations. It is shown that production of non-equivalent electron configurations is significant and involves electron-electron correlation effects whose analysis leads beyond the independent-particle model. Recent results that include a measurement at non-zero angles are presented to illustrate the angular dependence of electron emission from non-equivalent electron configurations, as well as the dependence on projectile charge state and target species. Comparison of high resolution scans over two lines of the 1s 2 2pnl sequence for the O 6+ + He system with accurate transition energy calculations shows preferential population of high angular momentum substation

  18. Electron capture in low- and intermediate-energy collisions between completely stripped light ions and metastable H(2s) targets

    International Nuclear Information System (INIS)

    Blanco, S.A.; Falcon, C.A.; Reinhold, C.O.; Casaubon, J.I.; Piacentini, R.D.

    1987-01-01

    Total cross sections for electron capture from H(2s) targets by He 2+ ions have been computed in the impact velocity range 0.05-0.5 au. Calculations were performed using a molecular close-coupling approach with inclusion of electron translation factors. A ten-state molecular basis set was considered. A comparison is made with Landau-Zener results for the same system. Intermediate projectile energy classical Monte Carlo capture cross sections are also presented for H + , He 2+ , Li 3+ and C 6+ projectiles. (author)

  19. Search of 2K(2ν) capture in 78 Kr and 124 Xe by means of wall-less proportional counters

    International Nuclear Information System (INIS)

    Volchenko, G.V.; Gavrilyuk, Yu.M.; Kuz'minov, V.V.; Osetrova, N.Ya.; Ratkevich, S.S.

    1998-01-01

    The technique of the experiment on the double two-neutrino K-capture search in isotopes of rare gases 78 Kr and 124 Xe is described. Multiwire wall-less proportional counters of a large volume are used in this experiment. Methods of decreasing the counter background noise in the energy range 10-100 keV are considered. These methods are based on the discrimination of events on the coordinate along the anode filament and the pulse rise time. The sensitivity of the experimental installation is estimated according to the half-life 78 Kr (1.2 x 10 21 years) and 124 Xe (2.6 x 10 20 years) with respect to the 2K(2ν) capture (68% certain level)

  20. A generalized electron energy probability function for inductively coupled plasmas under conditions of nonlocal electron kinetics

    Science.gov (United States)

    Mouchtouris, S.; Kokkoris, G.

    2018-01-01

    A generalized equation for the electron energy probability function (EEPF) of inductively coupled Ar plasmas is proposed under conditions of nonlocal electron kinetics and diffusive cooling. The proposed equation describes the local EEPF in a discharge and the independent variable is the kinetic energy of electrons. The EEPF consists of a bulk and a depleted tail part and incorporates the effect of the plasma potential, Vp, and pressure. Due to diffusive cooling, the break point of the EEPF is eVp. The pressure alters the shape of the bulk and the slope of the tail part. The parameters of the proposed EEPF are extracted by fitting to measure EEPFs (at one point in the reactor) at different pressures. By coupling the proposed EEPF with a hybrid plasma model, measurements in the gaseous electronics conference reference reactor concerning (a) the electron density and temperature and the plasma potential, either spatially resolved or at different pressure (10-50 mTorr) and power, and (b) the ion current density of the electrode, are well reproduced. The effect of the choice of the EEPF on the results is investigated by a comparison to an EEPF coming from the Boltzmann equation (local electron kinetics approach) and to a Maxwellian EEPF. The accuracy of the results and the fact that the proposed EEPF is predefined renders its use a reliable alternative with a low computational cost compared to stochastic electron kinetic models at low pressure conditions, which can be extended to other gases and/or different electron heating mechanisms.

  1. Angular distributions of projectiles following electron capture from C60 by 2.5-keV Ar8+

    International Nuclear Information System (INIS)

    Walch, B.; Thumm, U.; Stoeckli, M.; Cocke, C.L.; Klawikowski, S.

    1998-01-01

    Experimental measurements of the projectile angular distributions for 2.5-keV Ar 8+ ions capturing one to five electrons from a gas-phase C 60 target are presented. The number of captured electrons was determined by demanding a coincidence between the scattered projectile and a charge-state-analyzed intact C 60 recoil ion. The results are compared to calculations based on a dynamical classical overbarrier model. Good agreement is obtained only if the influence on the projectile trajectory by the large polarizability of the C 60 target is taken into account, thereby making the collective dielectric response of the cluster target observable in a scattering experiment. copyright 1998 The American Physical Society

  2. L-subshell resolved photon angular distribution of radiative electron capture into He-like uranium

    International Nuclear Information System (INIS)

    Stoehlker, T.; Geissel, H.; Irnich, H.; Kandler, T.; Kozhuharov, C.; Mokler, P.H.; Muenzenberg, G.; Nickel, F.; Scheidenberger, C.; Suzuki, T.; Kucharski, M.; Stachura, Z.; Kriessbach, A.; Shirai, T.

    1994-08-01

    The photon angular distributions for radiative electron capture (REC) into the j=1/2 and j=3/2 L-subshell levels were measured and calculated for U 90+ →C collisions at 89 MeV/u. The experiment provides the first study of the photon angular distribution of REC into a projectile p-state (j=3/2) which was found to exhibit a slight backward peaking in the laboratory frame. For radiative capture to the j=1/2 states the measured angular distribution deviates considerably from symmetry around 90 . The results demonstrate that the usual sin 2 θ lab distribution is not valid in the high-Z regime. (orig.)

  3. Liquid scintillation counting efficiency in three photomultiplier systems. Pure electron capture

    International Nuclear Information System (INIS)

    Los Arcos, J. M.; Grau Carles, A.; Grau Malonda, A.

    1990-01-01

    The tables of counting efficiency as a function of the figure of merit for a liquid scintillation counting system working with three phototubes are presented. The evaluation has been carried out for a Toluene-based scintillator with 5, 10 and 15 ml column, and 19 different radionuclides decaying by pure electron capture: 37Ar 41Ca, 49V, 53 Mn, 55Fe, 59Ni, 68Ge 7iGe, 82Sr, 97Tc, 118Te, 131CS, 137La, 140Ca, 157Tb, 165Er, 193Pt, 194Hg, 205Pb. (Author) 22 refs

  4. Capture of muons with high energy transfer (μ-,pn) on the 2040Ca

    International Nuclear Information System (INIS)

    Arques, Marc

    1978-01-01

    As several Russian experiments had shown that the capture of mesons of negative charge in some target nuclei (Si, S, Ca, Cu, Pb) could lead to the emission of high energy protons and neutrons (a kinetic energy higher than 30 MeV), the author reports a preliminary measurement of the capture or a negatively charged muon in a K orbit around a nucleus, actually a capture with a simultaneous emission of a proton and a neutron, and of a neutrino with an as low as possible energy. After having outlined the interest of such an experiment, the author describes the kinematics of capture of a resting muon, the production of muons, the experimental assembly, the experiment and the associated electronics. Results are interpreted

  5. Anisotropy evidence for the K-shell ionization probability in the use of Ag(p,p)Ag reaction

    International Nuclear Information System (INIS)

    Andriamonje, S.

    1976-01-01

    The ionization probability of silver by 1MeV protons has been measured at large angles up to 110 0 C. The experimental results have been obtained using the coincidence between scattered protons and KX rays. The angular dependence in the ionization probability at small impact parameters indicates an anisotropy as expected by Ciochetti and Molinari in their theoretical study of K-shell ionization probability associated with nuclear reactions. The results have been compared to the predictions of the BEA (Binary Exchange Approximation) method, including relativistic corrections of deflection and binding energy. The anisotropy coefficient deduced from the comparison of experimental and theoretical results is in good agreement with expected values [fr

  6. Improvement of the 400 kV linac electron source of AmPS

    International Nuclear Information System (INIS)

    Kroes, F.B.; Beuzekom, M.G. van; Dobbe, N.J.; Es, J.T. van; Jansweijer, P.P.M.; Kruijer, A.H.; Luigjes, G.; Sluijk, T.G.B.

    1992-01-01

    An existing linac (MEA) injects electrons into the Amsterdam Pulse Stretcher (AmPS) ring. The linac's peak current increases from 20 to 80 mA. This requires the modification of the 400 kV low emittance gun. The fourfold increase of the peak current is obtained by doubling both the gun perveance (new gun part) and the pulsed extractor voltage. To obtain optimum beam quality over this increased current range, the hot deck electronics has been exchanged by a fast high voltage FET switching supply. A built-in microprocessor, coupled to the local computer by optical fibers, is used to monitor and control the gun parameters. The 5 kV gun extractor voltage pulse shape can be monitored by means of an analog fibre transducer with build in calibration. Finally, in order to improve the energy stability of the accelerated electrons, a serial electron-tube stabilizer was added to the 400 kV DC power supply. (K.A.) 4 refs.; 6 figs

  7. Capture of a quantum particle by a moving trapping potential

    International Nuclear Information System (INIS)

    Shegelski, Mark R A; Poole, Tyler; Thompson, Cole

    2013-01-01

    We investigate the capture of a quantum particle in free space by a moving trapping potential. The capture is investigated for various initial conditions. We examine the dependence of the probability of capture on the shape and depth of the trapping potential, initial speed and mass of the particle, and other parameters. We take the trapping potential to move with an initial speed v 0 and to decelerate with constant acceleration a c until the well stops moving. We study the motion during the time the well is moving and after the well has stopped. We compare the probability of capture to the probability that the particle is in a stationary state (while the well is moving) and the probability the particle is in a bound state (after the well's motion has stopped). Our work could be of interest to instructors and students in upper-year undergraduate quantum mechanics courses. (paper)

  8. Potassium Capture by Kaolin, Part 1: KOH

    DEFF Research Database (Denmark)

    Wang, Guoliang; Jensen, Peter Arendt; Wu, Hao

    2018-01-01

    -capture level. The effect of reaction temperature,K-concentration in the flue gas, and, thereby, molar ratio of K/(Al+Si) in reactants, gas residence time, and solid particle size on K-capture reaction was systematically investigated. Corresponding equilibrium calculations were conducted with FactSage 7.......0. The experimental results showed that kaolin reached almost full conversion to K-aluminosilicates under suspension-fired conditions at 1100–1450 °C for a residence time of 1.2 s and a particle size of D50 = 5.47 μm. The amount of potassium captured by kaolin generally followed the equilibrium at temperatures above...

  9. Electron capture by multicharged ions at eV energies

    International Nuclear Information System (INIS)

    Havener, C.C.; Huq, M.S.; Meyer, F.W.; Phaneuf, R.A.

    1988-01-01

    A multicharged ion-atom merged-beams apparatus has been used in conjunction with the ORNL-ECR ion source to measure accurate absolute electron-capture cross sections in the energy range from below 1 eV/amu to 1500 eV/amu. Measurements for N/sup 3+,4+,5+/ /plus/ H(D) collisions indicate good agreement with available theoretical calculations. However, measurements with O 5+ /plus/ H(D) show an unexpected low-energy behavior which may be attributable to the ion-induced-dipole attraction between the reactants. Scaled Landau-Zener calculations presented here identify a transfer plus excitation channel which has the correct energy dependence at low energies. This finding suggest the need for a comprehensive coupled channel calculation which would include such product states. 25 refs., 8 figs

  10. Survival probability in small angle scattering of low energy alkali ions from alkali covered metal surfaces

    International Nuclear Information System (INIS)

    Neskovic, N.; Ciric, D.; Perovic, B.

    1982-01-01

    The survival probability in small angle scattering of low energy alkali ions from alkali covered metal surfaces is considered. The model is based on the momentum approximation. The projectiles are K + ions and the target is the (001)Ni+K surface. The incident energy is 100 eV and the incident angle 5 0 . The interaction potential of the projectile and the target consists of the Born-Mayer, the dipole and the image charge potentials. The transition probability function corresponds to the resonant electron transition to the 4s projectile energy level. (orig.)

  11. Negative pion capture in chemical compounds

    International Nuclear Information System (INIS)

    Butsev, V.S.; Chultem, D.; Gavrilov, Yu.K.; Ganzorig, Dz.; Norseev, Yu.V.; Presperin, V.

    1976-01-01

    The results are reported of an experiment of determination of the probability of capture of resting negative pions by iodine nuclei in alkali metal iodides (LiI, NaI, KI, RbI, CsI). The yield of an isomer sup(116m)(Sb/8 - ) with a high spin number, formed in the reaction 127 I(π - , lp 10n) allows to determine the relative probability of the nuclear capture of pions in the above compounds. The results obrained are compared with the predictions of the Fermi-Teller Z-law

  12. Comparison of Electronic Data Capture (EDC) with the Standard Data Capture Method for Clinical Trial Data

    Science.gov (United States)

    Walther, Brigitte; Hossin, Safayet; Townend, John; Abernethy, Neil; Parker, David; Jeffries, David

    2011-01-01

    Background Traditionally, clinical research studies rely on collecting data with case report forms, which are subsequently entered into a database to create electronic records. Although well established, this method is time-consuming and error-prone. This study compares four electronic data capture (EDC) methods with the conventional approach with respect to duration of data capture and accuracy. It was performed in a West African setting, where clinical trials involve data collection from urban, rural and often remote locations. Methodology/Principal Findings Three types of commonly available EDC tools were assessed in face-to-face interviews; netbook, PDA, and tablet PC. EDC performance during telephone interviews via mobile phone was evaluated as a fourth method. The Graeco Latin square study design allowed comparison of all four methods to standard paper-based recording followed by data double entry while controlling simultaneously for possible confounding factors such as interview order, interviewer and interviewee. Over a study period of three weeks the error rates decreased considerably for all EDC methods. In the last week of the study the data accuracy for the netbook (5.1%, CI95%: 3.5–7.2%) and the tablet PC (5.2%, CI95%: 3.7–7.4%) was not significantly different from the accuracy of the conventional paper-based method (3.6%, CI95%: 2.2–5.5%), but error rates for the PDA (7.9%, CI95%: 6.0–10.5%) and telephone (6.3%, CI95% 4.6–8.6%) remained significantly higher. While EDC-interviews take slightly longer, data become readily available after download, making EDC more time effective. Free text and date fields were associated with higher error rates than numerical, single select and skip fields. Conclusions EDC solutions have the potential to produce similar data accuracy compared to paper-based methods. Given the considerable reduction in the time from data collection to database lock, EDC holds the promise to reduce research-associated costs

  13. Comparison of electronic data capture (EDC with the standard data capture method for clinical trial data.

    Directory of Open Access Journals (Sweden)

    Brigitte Walther

    Full Text Available BACKGROUND: Traditionally, clinical research studies rely on collecting data with case report forms, which are subsequently entered into a database to create electronic records. Although well established, this method is time-consuming and error-prone. This study compares four electronic data capture (EDC methods with the conventional approach with respect to duration of data capture and accuracy. It was performed in a West African setting, where clinical trials involve data collection from urban, rural and often remote locations. METHODOLOGY/PRINCIPAL FINDINGS: Three types of commonly available EDC tools were assessed in face-to-face interviews; netbook, PDA, and tablet PC. EDC performance during telephone interviews via mobile phone was evaluated as a fourth method. The Graeco Latin square study design allowed comparison of all four methods to standard paper-based recording followed by data double entry while controlling simultaneously for possible confounding factors such as interview order, interviewer and interviewee. Over a study period of three weeks the error rates decreased considerably for all EDC methods. In the last week of the study the data accuracy for the netbook (5.1%, CI95%: 3.5-7.2% and the tablet PC (5.2%, CI95%: 3.7-7.4% was not significantly different from the accuracy of the conventional paper-based method (3.6%, CI95%: 2.2-5.5%, but error rates for the PDA (7.9%, CI95%: 6.0-10.5% and telephone (6.3%, CI95% 4.6-8.6% remained significantly higher. While EDC-interviews take slightly longer, data become readily available after download, making EDC more time effective. Free text and date fields were associated with higher error rates than numerical, single select and skip fields. CONCLUSIONS: EDC solutions have the potential to produce similar data accuracy compared to paper-based methods. Given the considerable reduction in the time from data collection to database lock, EDC holds the promise to reduce research

  14. The experiments of high power electron beam emission by the K-9M-57 and K-9M-58 rockets

    International Nuclear Information System (INIS)

    Kaneko, Osamu; Sasaki, Susumu; Yamori, Akira; Hagiwara, Michinobu; Kawashima, Nobuki

    1977-01-01

    Active experiments have been conducted to obtain the precise picture of the ionosphere and magnetosphere. As the turbulence source of the active experiment by the authors, electron beam was employed, and the variation of the rocket potential, wave excitation and turbulence of peripheral plasma were investigated. The rated voltage and current of the present electron gun were 6 kV and 500 mA, respectively. The Langmuir probe, floating probe, optical detector and wave receiver were used for the measurement of various phenomena associated with electron beam emission. The experimental data on the voltage-current characteristics of the electron gun, the rocket potential, total light emission and plasma density and temperature were obtained by the K-9M-57 and K-9M-58 rockets. (Yoshimori, M.)

  15. Study of K-REC with bare 60 MeV/u Kr ions channeled in a Si crystal. Experiments and simulations

    Energy Technology Data Exchange (ETDEWEB)

    Chevallier, M.; Dauvergne, D.; Krisch, R.; Poizat, J.C.; Remillieux, J. [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; Andriamonje, S. [Institut National de Physique Nucleaire et de Physique des Particules (IN2P3), 75 - Paris (France); Cohen, C.; L`Hoir, A. [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France); Cue, N. [Hong Kong Univ. (Hong Kong); Fujimoto, F. [CEA-Ecole Polytechnique, 91 - Palaiseau (France). Lab. d`Etudes des Solides Irradies] [and others

    1996-04-01

    K-shell Radiative Electron Capture (K-REC) measurements are presented with bare 60.1 MeV/u incident krypton ions, both in channeling conditions and for random orientation of a 37 {mu}m silicon crystal. Simulations of the K-REC photon lines have been developed. The K-REC photon peak was calculated within the non-relativistic dipole approximation, K-REC being assumed to be a purely local process. Solid state electron densities were used, and impact parameter dependent electron momentum distributions (Compton profiles) were calculated for 2s and 2p silicon electrons. (author). 31 refs.; Submitted to Physical Review, A (US).

  16. A technique for searching for the 2K capture in {sup 124}Xe with a copper proportional counter

    Energy Technology Data Exchange (ETDEWEB)

    Gavrilyuk, Yu. M.; Gangapshev, A. M.; Kazalov, V. V.; Kuzminov, V. V. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Panasenko, S. I.; Ratkevich, S. S. [Karazin Kharkiv National University (Ukraine); Tekueva, D. A., E-mail: t.jami.a@mail.ru; Yakimenko, S. P. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)

    2015-12-15

    An experimental technique for searching for the 2K capture in {sup 124}Xe with a large low-background copper proportional counter is described. Such an experiment is conducted at the Baksan Neutrino Observatory of the Institute for Nuclear Research of the Russian Academy of Sciences. The experimental setup is located in the Low-Background Deep-Level Laboratory at a depth of 4900 m.w.e., where the flux of muons of cosmic rays is suppressed by a factor of 10{sup 7} relative to that at the Earth’s surface. The setup incorporates a proportional counter and low-background shielding (18 cm of copper, 15 cm of lead, and 8 cm of borated polyethylene). The results of processing the data obtained in 5 months of live measurement time are presented. A new limit on the half-life of {sup 124}Xe with respect to the 2K capture is set at the level of 2.5 × 10{sup 21} years.

  17. Electron capture, electron loss, and deexcitation of fast H(2 2S) and H(1 2S) atoms in collisions with molecular hydrogen and inert gases

    International Nuclear Information System (INIS)

    Roussel, F.; Pradel, P.; Spiess, G.

    1977-01-01

    Collisions of ground-state (1 2 S) and metastable (2 2 S) hydrogen atoms with rare gases and molecular hydrogen have been studied in the energy range 0.5--3.0 keV. For an acceptance angle of 55 mrad, the electron loss and the electron-capture cross sections of both H(1 2 S) and H(2 2 S) have been measured and compared with previous experimental values. The deexcitation cross section for H(2 2 S) has been deduced with the help of previously measured total-quenching cross sections for H(2 2 S). The ratio of the electron-capture cross sections for H(2 2 S) relative to H(1 2 S) is found to be very large for argon at low energies. The effects of large-angle scattering and of highly excited states of H are discussed

  18. Electron-electron scattering-induced channel hot electron injection in nanoscale n-channel metal-oxide-semiconductor field-effect-transistors with high-k/metal gate stacks

    International Nuclear Information System (INIS)

    Tsai, Jyun-Yu; Liu, Kuan-Ju; Lu, Ying-Hsin; Liu, Xi-Wen; Chang, Ting-Chang; Chen, Ching-En; Ho, Szu-Han; Tseng, Tseung-Yuen; Cheng, Osbert; Huang, Cheng-Tung; Lu, Ching-Sen

    2014-01-01

    This work investigates electron-electron scattering (EES)-induced channel hot electron (CHE) injection in nanoscale n-channel metal-oxide-semiconductor field-effect-transistors (n-MOSFETs) with high-k/metal gate stacks. Many groups have proposed new models (i.e., single-particle and multiple-particle process) to well explain the hot carrier degradation in nanoscale devices and all mechanisms focused on Si-H bond dissociation at the Si/SiO 2 interface. However, for high-k dielectric devices, experiment results show that the channel hot carrier trapping in the pre-existing high-k bulk defects is the main degradation mechanism. Therefore, we propose a model of EES-induced CHE injection to illustrate the trapping-dominant mechanism in nanoscale n-MOSFETs with high-k/metal gate stacks.

  19. Theory of inelastic multiphonon scattering and carrier capture by defects in semiconductors: Application to capture cross sections

    Science.gov (United States)

    Barmparis, Georgios D.; Puzyrev, Yevgeniy S.; Zhang, X.-G.; Pantelides, Sokrates T.

    2015-12-01

    Inelastic scattering and carrier capture by defects in semiconductors are the primary causes of hot-electron-mediated degradation of power devices, which holds up their commercial development. At the same time, carrier capture is a major issue in the performance of solar cells and light-emitting diodes. A theory of nonradiative (multiphonon) inelastic scattering by defects, however, is nonexistent, while the theory for carrier capture by defects has had a long and arduous history. Here we report the construction of a comprehensive theory of inelastic scattering by defects, with carrier capture being a special case. We distinguish between capture under thermal equilibrium conditions and capture under nonequilibrium conditions, e.g., in the presence of an electrical current or hot carriers where carriers undergo scattering by defects and are described by a mean free path. In the thermal-equilibrium case, capture is mediated by a nonadiabatic perturbation Hamiltonian, originally identified by Huang and Rhys and by Kubo, which is equal to linear electron-phonon coupling to first order. In the nonequilibrium case, we demonstrate that the primary capture mechanism is within the Born-Oppenheimer approximation (adiabatic transitions), with coupling to the defect potential inducing Franck-Condon electronic transitions, followed by multiphonon dissipation of the transition energy, while the nonadiabatic terms are of secondary importance (they scale with the inverse of the mass of typical atoms in the defect complex). We report first-principles density-functional-theory calculations of the capture cross section for a prototype defect using the projector-augmented wave, which allows us to employ all-electron wave functions. We adopt a Monte Carlo scheme to sample multiphonon configurations and obtain converged results. The theory and the results represent a foundation upon which to build engineering-level models for hot-electron degradation of power devices and the performance

  20. Second-order symmetric eikonal approximation for electron capture at high energies

    Energy Technology Data Exchange (ETDEWEB)

    Deco, G R; Rivarola, R D [Rosario Univ. Nacional (Argentina). Dept. de Fisica

    1985-06-14

    A symmetric eikonal approximation for electron capture in ion-atom collisions at high energies has been developed within the Dodd and Greider (1966, Phys. Rev. 146 675) formalism. Implicit intermediate states are included through the choice of distorted initial and final wavefunctions. Explicit intermediate state are considered by the introduction of a free-particle Green's function G/sup +//sub 0/. The model is applied for the resonant charge exchange in H/sup +/+H(1s) collisions. Also, the characteristic dip of the continuum distorted-wave model is analysed when higher orders are included at 'realistic' high energies.

  1. Stopping power of K electrons at extreme relativistic energies

    International Nuclear Information System (INIS)

    Leung, P.T.; Rustgi, M.L.

    1983-01-01

    The recent work of Anholt on K-vacancy production by relativistic projectiles has been applied to calculate the stopping power of the K electrons. The results show that for protons of energy approx.10 3 GeV and heavy target elements, the relativistic contributions to the stopping power amount to several times the resuls due to the longitudinal terms obtained from Walske's work

  2. Photoion Auger-electron coincidence measurements near threshold

    International Nuclear Information System (INIS)

    Levin, J.C.; Biedermann, C.; Keller, N.; Liljeby, L.; Short, R.T.; Sellin, I.A.; Lindle, D.W.

    1990-01-01

    The vacancy cascade which fills an atomic inner-shell hole is a complex process which can proceed by a variety of paths, often resulting in a broad distribution of photoion charge states. We have measured simplified argon photoion charge distributions by requiring a coincidence with a K-LL or K-LM Auger electron, following K excitation with synchrotron radiation, as a function of photon energy, and report here in detail the argon charge distributions coincident with K-L 1 L 23 Auger electrons. The distributions exhibit a much more pronounced photon-energy dependence than do the more complicated non-coincident spectra. Resonant excitation of the K electron to np levels, shakeoff of these np electrons by subsequent decay processes, double-Auger decay, and recapture of the K photoelectron through postcollision interaction occur with significant probability. 17 refs

  3. A 1-kW power demonstration from the advanced free electron laser

    International Nuclear Information System (INIS)

    Sheffield, R.L.; Conner, C.A.; Fortgang, C.M.

    1997-01-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The main objective of this project was to engineer and procure an electron beamline compatible with the operation of a 1-kW free-electron laser (FEL). Another major task is the physics design of the electron beam line from the end of the wiggler to the electron beam dump. This task is especially difficult because electron beam is expected to have 20 kW of average power and to simultaneously have a 25% energy spread. The project goals were accomplished. The high-power electron design was completed. All of the hardware necessary for high-power operation was designed and procured

  4. A new magnetic spectrometer for the investigation of the internal conversion electron in capture reaction

    International Nuclear Information System (INIS)

    Suarez, A.A.

    1978-01-01

    Planning, development and manufacture of a new beta spectrometer for the investigation of the internal conversion electrons, from 0,02 to 10 MeV, emitted during the radioative capture process of the thermal neutrons. The resolution on the base of resolution curve is about 1,5 X 10 sup(-3) [pt

  5. Evidence for correlated double-electron capture in slow collisions of multicharged ions with He and H2

    International Nuclear Information System (INIS)

    Meyer, F.W.; Havener, C.C.; Phaneuf, R.A.; Swenson, J.K.; Shafroth, S.M.; Stolterfoht, N.

    1986-01-01

    High resolution measurements of the production of L 1 L 23 M Coster-Kronig and LMM-Auger electrons in slow collisions of C 4+ , N 5+ , O 6+ , and 0 7+ with He and H 2 have been performed, using the method of 0 0 Auger spectroscopy. For the latter three projectiles, strong Coster Kronig lines are observed, which are attributed to the configurations (core)2pnl, produced by double-electron capture. It is argued that production of these nonequivalent electron configurations must involve electron-electron correlation. From a comparison of the production cross sections for these Coster-Kronig electrons and the LMM-Auger electrons, it is further argued the correlation plays a significant role in two-electron transfer processes. 7 refs., 5 figs

  6. Negative muon capture in noble gas mixtures

    International Nuclear Information System (INIS)

    Hutson, R.L.; Knight, J.D.; Leon, M.; Schillaci, M.E.; Knowles, H.B.; Reidy, J.J.

    1980-01-01

    We have determined the probabilities of atomic negative muon capture in binary mixtures of the gases He, Ne, Ar, and Kr at partial pressures near five atmospheres. Relative capture rates were deduced from measured muonic X-ray yields. (orig.)

  7. ELECTRON-CAPTURE AND β-DECAY RATES FOR sd-SHELL NUCLEI IN STELLAR ENVIRONMENTS RELEVANT TO HIGH-DENSITY O–NE–MG CORES

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Toshio [Department of Physics and Graduate School of Integrated Basic Sciences, College of Humanities and Sciences, Nihon University Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan); Toki, Hiroshi [Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka 567-0047 (Japan); Nomoto, Ken’ichi, E-mail: suzuki@phys.chs.nihon-u.ac.jp [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan)

    2016-02-01

    Electron-capture and β-decay rates for nuclear pairs in the sd-shell are evaluated at high densities and high temperatures relevant to the final evolution of electron-degenerate O–Ne–Mg cores of stars with initial masses of 8–10 M{sub ⊙}. Electron capture induces a rapid contraction of the electron-degenerate O–Ne–Mg core. The outcome of rapid contraction depends on the evolutionary changes in the central density and temperature, which are determined by the competing processes of contraction, cooling, and heating. The fate of the stars is determined by these competitions, whether they end up with electron-capture supernovae or Fe core-collapse supernovae. Since the competing processes are induced by electron capture and β-decay, the accurate weak rates are crucially important. The rates are obtained for pairs with A = 20, 23, 24, 25, and 27 by shell-model calculations in the sd-shell with the USDB Hamiltonian. Effects of Coulomb corrections on the rates are evaluated. The rates for pairs with A = 23 and 25 are important for nuclear Urca processes that determine the cooling rate of the O–Ne–Mg core, while those for pairs with A = 20 and 24 are important for the core contraction and heat generation rates in the core. We provide these nuclear rates at stellar environments in tables with fine enough meshes at various densities and temperatures for studies of astrophysical processes sensitive to the rates. In particular, the accurate rate tables are crucially important for the final fates of not only O–Ne–Mg cores but also a wider range of stars, such as C–O cores of lower-mass stars.

  8. ELECTRON-CAPTURE AND β-DECAY RATES FOR sd-SHELL NUCLEI IN STELLAR ENVIRONMENTS RELEVANT TO HIGH-DENSITY O–NE–MG CORES

    International Nuclear Information System (INIS)

    Suzuki, Toshio; Toki, Hiroshi; Nomoto, Ken’ichi

    2016-01-01

    Electron-capture and β-decay rates for nuclear pairs in the sd-shell are evaluated at high densities and high temperatures relevant to the final evolution of electron-degenerate O–Ne–Mg cores of stars with initial masses of 8–10 M ⊙ . Electron capture induces a rapid contraction of the electron-degenerate O–Ne–Mg core. The outcome of rapid contraction depends on the evolutionary changes in the central density and temperature, which are determined by the competing processes of contraction, cooling, and heating. The fate of the stars is determined by these competitions, whether they end up with electron-capture supernovae or Fe core-collapse supernovae. Since the competing processes are induced by electron capture and β-decay, the accurate weak rates are crucially important. The rates are obtained for pairs with A = 20, 23, 24, 25, and 27 by shell-model calculations in the sd-shell with the USDB Hamiltonian. Effects of Coulomb corrections on the rates are evaluated. The rates for pairs with A = 23 and 25 are important for nuclear Urca processes that determine the cooling rate of the O–Ne–Mg core, while those for pairs with A = 20 and 24 are important for the core contraction and heat generation rates in the core. We provide these nuclear rates at stellar environments in tables with fine enough meshes at various densities and temperatures for studies of astrophysical processes sensitive to the rates. In particular, the accurate rate tables are crucially important for the final fates of not only O–Ne–Mg cores but also a wider range of stars, such as C–O cores of lower-mass stars

  9. Distinguishing of Ile/Leu amino acid residues in the PP3 protein by (hot) electron capture dissociation in Fourier transform ion cyclotron resonance mass spectrometry

    DEFF Research Database (Denmark)

    Kjeldsen, Frank; Haselmann, Kim F; Sørensen, Esben Skipper

    2003-01-01

    In hot electron capture dissociation (HECD), multiply protonated polypeptides fragment upon capturing approximately 11-eV electrons. The excess of energy upon the primary c, z* cleavage induces secondary fragmentation in z* fragments. The resultant w ions allow one to distinguish between the isom...

  10. Measurement of low energy neutrino absorption probability in thallium 205

    International Nuclear Information System (INIS)

    Freedman, M.S.

    1986-01-01

    A major aspect of the P-P neutrino flux determination using thallium 205 is the very difficult problem of experimentally demonstrating the neutrino reaction cross section with about 10% accuracy. One will soon be able to completely strip the electrons from atomic thallium 205 and to maintain the bare nucleus in this state in the heavy storage ring to be built at GSI Darmstadt. This nucleus can decay by emitting a beta-minus particle into the bound K-level of the daughter lead 205 ion as the only energetically open decay channel, (plus, of course, an antineutrino). This single channel beta decay explores the same nuclear wave functions of initial and final states as does the neutrino capture in atomic thallium 205, and thus its probability or rate is governed by the same nuclear matrix elements that affect both weak interactions. Measuring the rate of accumulation of lead 205 ions in the circulating beam of thallium 205 ions gives directly the cross section of the neutrino capture reaction. The calculations of the expected rates under realistic experimental conditions will be shown to be very favorable for the measurement. A special calibration experiment to verify this method and check the theoretical calculations will be suggested. Finally, the neutrino cross section calculation based on the observed rate of the single channel beta-minus decay reaction will be shown. Demonstrating bound state beta decay may be the first verification of the theory of this very important process that influences beta decay rates of several isotopes in stellar interiors, e.g., Re-187, that play important roles in geologic and cosmologic dating and nucleosynthesis. 21 refs., 2 figs

  11. Wave functions and two-electron probability distributions of the Hooke's-law atom and helium

    International Nuclear Information System (INIS)

    O'Neill, Darragh P.; Gill, Peter M. W.

    2003-01-01

    The Hooke's-law atom (hookium) provides an exactly soluble model for a two-electron atom in which the nuclear-electron Coulombic attraction has been replaced by a harmonic one. Starting from the known exact position-space wave function for the ground state of hookium, we present the momentum-space wave function. We also look at the intracules, two-electron probability distributions, for hookium in position, momentum, and phase space. These are compared with the Hartree-Fock results and the Coulomb holes (the difference between the exact and Hartree-Fock intracules) in position, momentum, and phase space are examined. We then compare these results with analogous results for the ground state of helium using a simple, explicitly correlated wave function

  12. Electron capture and excitation in collisions of O+(4S,2D,2P) with H2 molecules

    International Nuclear Information System (INIS)

    Pichl, Lukas; Li Yan; Liebermann, Heinz-Peter; Buenker, Robert J.; Kimura, Mineo

    2004-01-01

    Using an electronic-state close-coupling method, we treated the electron capture and excitation processes of O + ions both in ground state O + ( 4 S) and metastable states O +* ( 2 D) and O +* ( 2 P) in collisions with the H 2 molecule. In the ground-state projectile energy region considered (from 50 eV/amu to 10 keV/amu), the experimental data vary by orders of magnitude: our results smoothly connect to the data by Flesch and Ng [J. Chem. Phys. 94, 2372 (1991)] and Xu et al. [J. Phys. B 23, 1235 (1990)] at low energy and agree with Phaneuf et al. [Phys. Rev. A 17, 534 (1978)] in the high-energy region. The present values differ from Sieglaff et al. [Phys. Rev. A 59, 3538 (1999)] and Nutt et al. [J. Phys. B 12, L157 (1979)], especially in the energy region below 1 keV/amu. We provide the first calculated state-resolved cross sections of electron capture and target-projectile electronic excitations for the O + ( 4 S, 2 D, 2 P)-H 2 collision system

  13. COINCIDENCES BETWEEN ELECTRONS AND TARGET IONS TO IDENTIFY CAPTURE CHANNELS IN COLLISIONS OF MULTIPLY CHARGED IONS ON GAS TARGETS

    NARCIS (Netherlands)

    POSTHUMUS, JH; MORGENSTERN, R

    1992-01-01

    We have investigated multielectron capture processes in collisions of Ar9+ on Ar by measuring the resulting Auger electrons in coincidence with charge-state-analyzed target ions. In this way it was possible to reconstruct partial electron energy spectra, each corresponding to a particular number of

  14. Probability of defect detection of Posiva's electron beam weld

    International Nuclear Information System (INIS)

    Kanzler, D.; Mueller, C.; Pitkaenen, J.

    2013-12-01

    The report 'Probability of Defect Detection of Posiva's electron beam weld' describes POD curves of four NDT methods radiographic testing, ultrasonic testing, eddy current testing and visual testing. POD-curves are based on the artificial defects in reference blocks. The results are devoted to the demonstration of suitability of the methods for EB weld testing. Report describes methodology and procedure applied by BAM. Report creates a link from the assessment of the reliability and inspection performance to the risk assessment process of the canister final disposal project. Report ensures the confirmation of the basic quality of the NDT methods and their capability to describe the quality of the EB-weld. The probability of detection curves are determined based on the MIL-1823 standard and it's reliability guidelines. The MIL-1823 standard was developed for the determination of integrity of gas turbine engines for the US military. In the POD-process there are determined as a key parameter for the defect detectability the a90/95 magnitudes, i.e. the size measure a of the defect, for which the lower 95 % confidence band crosses the 90 % POD level. By this way can be confirmed that defects with a size of a90/95 will be detected with 90 % probability. In case the experiment will be repeated 5 % might fall outside this confidence limit. (orig.)

  15. Measurement of K-p radiative capture to γΛ and γΣ0 for pK- between 514 and 750 MeV/c

    International Nuclear Information System (INIS)

    Prakhov, S.; Phaisangittisakul, N.; Nefkens, B. M. K.; Marusic, A.; McDonald, S.; Price, J. W.; Starostin, A.; Vancraeyveld, P.; De Cruz, L.; Ryckebusch, J.; Van Cauteren, T.; Bekrenev, V.; Koulbardis, A.; Kozlenko, N.; Kruglov, S.; Lopatin, I.; Briscoe, W. J.; Shafi, A.; Strakovsky, I. I.; Isenhower, D.

    2010-01-01

    Differential cross sections for K - radiative capture in flight on the proton, leading to the γΛ and γΣ 0 final states, have been measured at eight K - momenta between 514 and 750 MeV/c. The data were obtained with the Crystal Ball multiphoton spectrometer installed at the separated K/π beam line C6 of the BNL Alternating Gradient Synchrotron. The results substantially improve the existing experimental data available for studying radiative decays of excited hyperon states. An exploratory theoretical analysis is performed within the Regge-plus-resonance approach. According to this analysis, the γΣ 0 final state is dominated by hyperon-resonance exchange and hints at an important role for a resonance in the mass region of 1700 MeV. In the γΛ final state, in contrast, the resonant contributions account for only half the strength, and the data suggest the importance of a resonance in the mass region of 1550 MeV.

  16. Computation of the average energy for LXY electrons

    International Nuclear Information System (INIS)

    Grau Carles, A.; Grau, A.

    1996-01-01

    The application of an atomic rearrangement model in which we only consider the three shells K, L and M, to compute the counting efficiency for electron capture nuclides, requires a fine averaged energy value for LMN electrons. In this report, we illustrate the procedure with two example, ''125 I and ''109 Cd. (Author) 4 refs

  17. Impact-parameter dependence of the total probability for electromagnetic electron-positron pair production in relativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    Hencken, K.; Trautmann, D.; Baur, G.

    1995-01-01

    We calculate the impact-parameter-dependent total probability P total (b) for the electromagnetic production of electron-positron pairs in relativistic heavy-ion collisions in lowest order. We study expecially impact parameters smaller than the Compton wavelength of the electron, where the equivalent-photon approximation cannot be used. Calculations with and without a form factor for the heavy ions are done; the influence is found to be small. The lowest-order results are found to violate unitarity and are used for the calculation of multiple-pair production probabilities with the help of the approximate Poisson distribution already found in earlier publications

  18. Theory of K-MM radiative-Auger transitions

    International Nuclear Information System (INIS)

    Baptista, G.B.

    1975-01-01

    Presently available calculations of transition probabilities for radiative-Auger and double-Auger processes are based on shake-off theory. In this theory, such processes are thought of as being due to electron core rearrangement associated with de-excitation of an inner shell vacancy. It is suggested that radiative-Auger processes result from the interaction of two electrons with one another and the radiation field in the presence of an inner shell vacancy, while double-Auger processes result from the interaction of an electron with two electrons in the presence of a similar vacancy. Expressions for the transition probabilities of these processes are derived in second order time dependent perturbation theory. The interaction is taken as the sum of the Coulomb interaction and electron-field interaction of the electrons involved. This approach allows calculation of the detailed photon or electron energy distribution resulting from such processes, as well as the relative and absolute transition rates involved. As a specific example of this approach the transition probability for the K-MM radiative-Auger effect in argon is calculated and compared with available experimental data. Scaled Thomas-Fermi wavefunctions are used to calculate the total transition probability which is found to be 2.68 x 10 -4 eV/h-bar In addition, the spectral distribution of emitted photons is obtained, and agreement both in magnitude and with the general features of the experimental data is excellent

  19. Design of diode electron gun for 250 kW CW klystron

    International Nuclear Information System (INIS)

    Prasad, M.; Pande, S.A.; Hannurkar, P.R.

    2005-01-01

    A 250 kW CW klystron at frequencies 350 MHz and 700 MHz is being developed at Centre for Advanced Technology. These klystrons are required for forthcoming project like 100 MeV proton Linac for Spallation Neutron Source (SNS) as a main rf sources. In order to develop klystrons, we have designed the diode electron gun, which delivers more than 10 A beam current at 50 kV. This paper describes the simulation results of electron gun with computer code EGUN. (author)

  20. Compact Source of Electron Beam with Energy of 200 kEv and Average Power of 2 kW

    CERN Document Server

    Kazarezov, Ivan; Balakin, Vladimir E; Bryazgin, Alex; Bulatov, Alexandre; Glazkov, Ivan; Kokin, Evgeny; Krainov, Gennady; Kuznetsov, Gennady I; Molokoedov, Andrey; Tuvik, Alfred

    2005-01-01

    The paper describes a compact electron beam source with average electron energy of 200 keV. The source operates with pulse power up to 2 MW under average power not higher than 2 kW, pulsed beam current up to 10 A, pulse duration up to 2 mks, and repetition rate up to 5 kHz. The electron beam is extracted through aluminium-beryllium alloy foil. The pulse duration and repetition rate can be changed from control desk. High-voltage generator for the source with output voltage up to 220 kV is realized using the voltage-doubling circuit which consists of 30 sections. The insulation type - gas, SF6 under pressure of 8 atm. The cooling of the foil supporting tubes is provided by a water-alcohol mixture from an independent source. The beam output window dimensions are 180?75 mm, the energy spread in the beam +10/-30%, the source weight is 80 kg.

  1. Comparison of quantification methods for the analysis of polychlorinated alkanes using electron capture negative ionization mass spectrometry.

    NARCIS (Netherlands)

    Rusina, T.; Korytar, P.; de Boer, J.

    2011-01-01

    Four quantification methods for short-chain chlorinated paraffins (SCCPs) or polychlorinated alkanes (PCAs) using gas chromatography electron capture negative ionisation low resolution mass spectrometry (GC-ECNI-LRMS) were investigated. The method based on visual comparison of congener group

  2. Comparison of quantification methods for the analysis of polychlorinated alkanes using electron capture negative ionisation mass spectrometry

    NARCIS (Netherlands)

    Rusina, T.; Korytar, P.; Boer, de J.

    2011-01-01

    Four quantification methods for short-chain chlorinated paraffins (SCCPs) or polychlorinated alkanes (PCAs) using gas chromatography electron capture negative ionisation low resolution mass spectrometry (GC-ECNI-LRMS) were investigated. The method based on visual comparison of congener group

  3. Design and simulation of a 30 kV, 60 kW electron optical column for melting applications

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Sachin; Kandaswamy, E.; Bapat, A.V., E-mail: saching@barc.gov.in [Bhabha Atomic Research Centre, Mumbai (India)

    2014-07-01

    Electron beam offers unique advantages as a heat source for melting of refractory metals. It provides contamination free homogeneous melting with precise heat control on the melt target. This paper reports the complete electron optics design procedure for a 30 kV, 60 kW melting gun. The design objective of the electron optical column is to obtain the required power density on the target (10{sup 3}-10{sup 4} W/cm{sup 2}) using electrostatic and electromagnetic lenses. The design constrains are to minimize the high voltage discharges in the gun and beam losses in the beam transport. The challenging task of reducing the electrical discharges in the gun during high power melting with the help of twin electromagnetic lenses is presented in the paper. (author)

  4. Independent center, independent electron approximation for dynamics of molecules and clusters

    International Nuclear Information System (INIS)

    McGuire, J.H.; Straton, J.C.; Wang, J.; Wang, Y.D.; Weaver, O.L.; Corchs, S.E.; Rivarola, R.D.

    1996-01-01

    A formalism is developed for evaluating probabilities and cross sections for multiple-electron transitions in scattering of molecules and clusters by charged collision partners. First, the molecule is divided into subclusters each made up of identical centers (atoms). Within each subcluster coherent scattering from identical centers may lead to observable phase terms and a geometrical structure factor. Then, using a mean field approximation to describe the interactions between centers we obtain A I ∼ summation k product ke iδ k I A Ik . Second, the independent electron approximation for each center may be obtained by neglecting the correlation between electrons in each center. The probability amplitude for each center is then a product of single electron transition probability amplitudes, a Ik i , i.e. A Ik ≅ product iaik i . Finally, the independent subcluster approximation is introduced by neglecting the interactions between different subclusters in the molecule or cluster. The total probability amplitude then reduces to a simple product of amplitudes for each subcluster, A≅ product IAI . Limitations of this simple approximation are discussed. copyright 1996 American Institute of Physics

  5. Dipole and Coulomb forces in electron capture dissociation and electron transfer dissociation mass spectroscopy.

    Science.gov (United States)

    Świerszcz, Iwona; Skurski, Piotr; Simons, Jack

    2012-02-23

    Ab initio electronic structure calculations were performed on a doubly charged polypeptide model H(+)-Lys(Ala)(19)-CO-CH(NH(2))-CH(2)-SS-CH(2)-(NH(2))CH-CO-(Ala)(19)-Lys-H(+) consisting of a C-terminal protonated Lys followed by a 19-Ala α-helix with a 20th Ala-like unit whose side chain is linked by a disulfide bond to a corresponding Ala-like unit connected to a second 19-Ala α-helix terminated by a second C-terminal-protonated Lys. The Coulomb potentials arising from the two charged Lys residues and dipole potentials arising from the two oppositely directed 72 D dipoles of the α-helices act to stabilize the SS bond's σ* orbital. The Coulomb potentials provide stabilization of 1 eV, while the two large dipoles generate an additional 4 eV. Such stabilization allows the SS σ* orbital to attach an electron and thereby generate disulfide bond cleavage products. Although calculations are performed only on SS bond cleavage, discussion of N-C(α) bond cleavage caused by electron attachment to amide π* orbitals is also presented. The magnitudes of the stabilization energies as well as the fact that they arise from Coulomb and dipole potentials are supported by results on a small model system consisting of a H(3)C-SS-CH(3) molecule with positive and negative fractional point charges to its left and right designed to represent (i) two positive charges ca. 32 Å distant (i.e., the two charged Lys sites of the peptide model) and (ii) two 72 D dipoles (i.e., the two α-helices). Earlier workers suggested that internal dipole forces in polypeptides could act to guide incoming free electrons (i.e., in electron capture dissociation (ECD)) toward the positive end of the dipole and thus affect the branching ratios for cleaving various bonds. Those workers argued that, because of the huge mass difference between an anion donor and a free electron, internal dipole forces would have a far smaller influence over the trajectory of a donor (i.e., in electron transfer dissociation

  6. Electron capture by Ne3+ ions from atomic hydrogen

    International Nuclear Information System (INIS)

    Rejoub, R.; Bannister, M.E.; Havener, C.C.; Savin, D.W.; Verzani, C.J.; Wang, J.G.; Stancil, P.C.

    2004-01-01

    Using the Oak Ridge National Laboratory ion-atom merged-beam apparatus, absolute total electron-capture cross sections have been measured for collisions of Ne 3+ ions with hydrogen (deuterium) atoms at energies between 0.07 and 826 eV/u. Comparison to previous measurements shows large discrepancies between 50 and 400 eV/u. Previously published molecular-orbital close-coupling (MOCC) calculations were performed over limited energy ranges, but show good agreement with the present measurements. Here MOCC calculations are presented for energies between 0.01 and 1000 eV/u for collisions with both H and D. For energies below ∼1 eV/u, an enhancement in the magnitude of both the experimental and theoretical cross sections is observed which is attributed to the ion-induced dipole attraction between the reactants. Below ∼4 eV/u, the present calculations show a significant target isotope effect

  7. Electron capture by Ne3+ ions from atomic hydrogen

    Science.gov (United States)

    Rejoub, R.; Bannister, M. E.; Havener, C. C.; Savin, D. W.; Verzani, C. J.; Wang, J. G.; Stancil, P. C.

    2004-05-01

    Using the Oak Ridge National Laboratory ion-atom merged-beam apparatus, absolute total electron-capture cross sections have been measured for collisions of Ne3+ ions with hydrogen (deuterium) atoms at energies between 0.07 and 826 eV/u . Comparison to previous measurements shows large discrepancies between 50 and 400 eV/u . Previously published molecular-orbital close-coupling (MOCC) calculations were performed over limited energy ranges, but show good agreement with the present measurements. Here MOCC calculations are presented for energies between 0.01 and 1000 eV/u for collisions with both H and D. For energies below ˜1 eV/u , an enhancement in the magnitude of both the experimental and theoretical cross sections is observed which is attributed to the ion-induced dipole attraction between the reactants. Below ˜4 eV/u , the present calculations show a significant target isotope effect.

  8. Electron spectroscopy studies of argon K-shell excitation and vacancy cascades

    International Nuclear Information System (INIS)

    Southworth, S.H.; MacDonald, M.A.; LeBrun, T.; Azuma, Y.; Cooper, J.W.

    1995-01-01

    Electron spectroscopy combined with tunable synchrotron radiation has been used for studies of Ar K-shell excitation and vacancy decay processes. In addition, electrons and fluorescent X-rays have been recorded in coincidence to select subsets of the ejected electron spectra. Examples are presented for Ar 1s photoelectrons and KLL and LMM Auger spectra

  9. Particle Identification in the T2K TPCs and study of the electron neutrino component in the T2K neutrino beam

    International Nuclear Information System (INIS)

    Giganti, Claudio

    2010-01-01

    our method we measured a deposited energy resolution of 7.5% for Minimum Ionizing Particles. I developed and tested the TPC PID methods using a Monte Carlo simulation based on the Near Detector official software. The energy loss curve was parameterized as a function of the βγ of the particle and then we defined a pull variable to give the particle identification probability. These methods are described in the chapter 4 of this thesis. We also validated the PID methods using the TPC beam test. I directly participated to these beam tests that were performed at TRIUMF for each of the TPCs in 2008 and 2009. The beam provided monoenergetic particles (pions, muons and electrons) with momenta up to 400 MeV/c. I analyzed the data of the beam tests for each of the TPC, checking the dependencies of the deposited energy on the momentum, the angle, the number of samples and the external conditions. This analysis allowed us to validate the PID methods and the TPC performances before the installation in Japan and the results are shown in chapter 5. In the Autumn of 2009 the TPCs were installed and commissioned at JPARC, in the Near Detector hall. During the thesis I spent 4 months at JPARC working on the installation of the TPCs, on the electronics and the data acquisition commissioning and on the TPC online monitoring. I also analyzed the first cosmic and beam data taken in 2010 to check the Particle Identification measurements. The results are shown in chapter 6. I also made a Monte Carlo based analysis to measure the electron neutrino component in the T2K beam: the analysis, described in chapter 7, mainly uses the TPC PID capabilities and shows the feasibility of this measurement, with a residual background mainly coming from electrons entering the TPCs and not generated by ν e . Finally in the chapter 8 I will show the analysis at the Near Detector of the first physics run of the T2K experiment. We performed a selection of the electron neutrinos interactions in the near

  10. Measurement of the intensity ratio of Auger and conversion electrons for the electron capture decay of 125I

    Science.gov (United States)

    Alotiby, M.; Greguric, I.; Kibédi, T.; Lee, B. Q.; Roberts, M.; Stuchbery, A. E.; Tee, Pi; Tornyi, T.; Vos, M.

    2018-03-01

    Auger electrons emitted after nuclear decay have potential application in targeted cancer therapy. For this purpose it is important to know the Auger electron yield per nuclear decay. In this work we describe a measurement of the ratio of the number of conversion electrons (emitted as part of the nuclear decay process) to the number of Auger electrons (emitted as part of the atomic relaxation process after the nuclear decay) for the case of 125I. Results are compared with Monte-Carlo type simulations of the relaxation cascade using the BrIccEmis code. Our results indicate that for 125I the calculations based on rates from the Evaluated Atomic Data Library underestimate the K Auger yields by 20%.

  11. Measurement of the intensity ratio of Auger and conversion electrons for the electron capture decay of 125I.

    Science.gov (United States)

    Alotiby, M; Greguric, I; Kibédi, T; Lee, B Q; Roberts, M; Stuchbery, A E; Tee, Pi; Tornyi, T; Vos, M

    2018-03-21

    Auger electrons emitted after nuclear decay have potential application in targeted cancer therapy. For this purpose it is important to know the Auger electron yield per nuclear decay. In this work we describe a measurement of the ratio of the number of conversion electrons (emitted as part of the nuclear decay process) to the number of Auger electrons (emitted as part of the atomic relaxation process after the nuclear decay) for the case of 125 I. Results are compared with Monte-Carlo type simulations of the relaxation cascade using the BrIccEmis code. Our results indicate that for 125 I the calculations based on rates from the Evaluated Atomic Data Library underestimate the K Auger yields by 20%.

  12. Electron addition to alkyl cobalamins, coenzyme B12 and vitamin B12

    International Nuclear Information System (INIS)

    Rao, D.N.R.; Symons, M.C.R.

    1983-01-01

    Exposure of dilute solutions of methyl and ethyl cobalamins and coenzyme B 12 in dilute solutions (D 2 O+CD 3 OD) to 60 Co #betta#-rays at 77 K gave a single broad feature in the free-spin region assigned to electron-capture species with the excess electron largely confined to a π* corrin orbital. On warming above 77 K the methyl derivative gave a novel species with spectral features characteristic of an unpaired electron in the Co(dsub(x 2 -y 2 )) orbital. The other two substrates gave spectra due to Cosup(II)Bsub(12r) both on warming and after photolyses with visible light. The acetyl derivative gave an electron-capture species whose e.s.r. spectrum was characteristic of an electron in the Co(dsub(z 2 )) orbital, which on warming above 77 K changed to the normal Cosup(II)Bsub(12r) spectrum. The cyano derivative (vitamin B 12 ) gave electron addition into the Co(dsub(z 2 )) orbital, as evidenced by the large hyperfine coupling to 13 C from 13 CN ligands. On annealing, cyanide ions were lost irreversibly, Bsub(12r) being detected by e.s.r. spectroscopy. In contrast, the dicyano derivative on electron addition at 77 K gave a species containing only one 13 CN ligand. Hence in this case one CN - ligand was lost at 77 K, with no return of the dimethylbenzimidazole ligand. These results are discussed in terms of a new mechanism for electron-addition to alkyl cobalamins. (author)

  13. Effect of electron correlation on the forced electric dipole transition probabilities in fsup(N) systems

    International Nuclear Information System (INIS)

    Jankowski, K.; Smentek-Mielczarek, L.

    1981-01-01

    Results of model studies of the impact of electron correlation on the forced electric dipole transition probabilities between states of the 4fsup(N) configuration are reported for the [ 3 P] 0 - [ 3 F] 4 , [ 3 H] 4 transitions in Pr 3+ : LaCl 3 and for [ 7 F] 0 - [ 5 D] 2 , [ 7 F] 1 - [ 5 D] 1 hypersensitive transitions in Eu 3+ : LaCl 3 . For the former system the correlation effects cause a modification of earlier results by 40-95 per cent, whereas for the latter the probability changes by as much as two orders of magnitude. The great changes found in the case of hypersensitive transitions suggest that electron correlation effects may belong to the most important factors determining the nature of these transitions. Several types of effective correlation operators are considered and their relative importance is discussed. The results indicate that intermediate configurations including g orbitals are very important for the description of correlation effects. (author)

  14. A 120kV IGBT modulator for driving a Pierce electron gun

    International Nuclear Information System (INIS)

    Earley, Lawrence M.; Brown, Richard W.; Carlson, Randolph L.; Ferguson, Patrick; Haynes, William B.; Kirbie, Hugh C.; Russell, Steven J.; Sigler, Floyd E.; Smirnova, Evgenya I.; Wheat, Robert M. Jr.

    2004-01-01

    An IGBT modulator has been developed to drive a 120 kV, 23 A Pierce electron gun. The modulator is capable of producing pulses up to 10 μs in width at repetition rates up to 10Hz with no active reset. The pulse rise time on the electron gun will be approximately 2 μs and the remaining 8 μs of flattop is tuned to have a ripple of less than 1 percent rms. The modulator technology was developed from a previous 50 kV prototype. The modulator consists of six boards, each with one EUPEC IGBT that drives a single common step-up transformer wound on METGLAS 2605SC cores. The six transformer cores share a common bi-filar output secondary winding. The modulator uses a fiber optic trigger system and has a high voltage cable output with an epoxy receptacle on the oil end and a ceramic receptacle on the vacuum end. The 120 kV electron gun was manufactured by MDS Co. and will be used to generate sheet electron beams from the standard pencil beam produced by the Pierce electron gun.

  15. Capture of negative muons in magnesium oxides and crystalline modifications of phosphorus

    International Nuclear Information System (INIS)

    Zinov, V.G.; Kachalkin, A.K.; Nikityuk, L.N.; Pokrovskij, V.N.; Rybakov, V.N.; Yutlandov, I.A.

    1977-01-01

    The paper is aimed at comparing the structure of mesic K X-ray patterns of phosphorus in its crystalline modifications, comparing the structure of mesic X-ray patterns of magnesium and oxygen in compounds of MgO, MgO 2 , H 2 O and metallic magnesium, as well as comparison of propabilities of μ - atomic capture in magnesium oxides. By analyzing the mesic K X-ray patterns of red and white phosphorus it is concluded that the phosphorus crystalline modification produces the effect on the line structure, the higher series number being somewhat larger for the allotrope of phosphorus with polymeric structure. A comparison is made of the mesic X-ray series of the magnesium in oxide and metal, of the oxygen in oxide and water with the analogous data for aluminium and silicon. The data confirm the supposition that chemical bond (valence electrons) plays a substantial role in meson capture

  16. K-intercalated carbon systems: Effects of dimensionality and substrate

    KAUST Repository

    Kaloni, Thaneshwor P.; Kahaly, M. Upadhyay; Cheng, Yingchun; Schwingenschlö gl, Udo

    2012-01-01

    the charge carrier density. Reasonably high values are found for all systems, the highest carrier density for the bilayer. The band structure and electron-phonon coupling of free-standing K-intercalated bilayer graphene points to a high probability

  17. Double-electron excitation above Xe K-edge

    International Nuclear Information System (INIS)

    Ito, Y.; Tochio, T.; Vlaicu, A.M.; Mutaguchi, K.; OhHashi, H.; Shigeoka, N.; Nakata, Y.; Akahama, Y.; Uruga, T.; Emura, Sh.

    2000-01-01

    When X-rays fall on any substance, whether solid, liquid, or gaseous, a photoabsorption occurs. Photoabsorption in atoms has been generally treated as a single-electron excitation process. However, the existence of the multi-electron excitation process, where the removal of a core electron by photoabsorption causes excitation of additional electrons in the same atoms, has been known in x-ray absorption spectra for a long time. In x-ray absorption spectra, experimental investigations of the shake processes in inner-shell ionization phenomena have been performed by detecting discontinuities. The shake effect which is a consequence of rearrangement of the atomic electrons, occurs in association with inner-shell excitation and ionization phenomena in x-ray absorption. The shake process has been studied extensively in various gases, because it is usually considered that the measurement of the multi-electron excitation is only possible for monatomic gases or vapors. The x-ray absorption spectra in Kr gas were measured by Ito et al. in order to observe precisely x-ray absorption spectra and to investigate the multi-electron excitation cross sections in Kr as a function of photon energy using synchrotron radiation. However, no suitable measured K x-ray absorption spectra was available to elucidate the shake processes. In the present work, the photoabsorption cross sections in Xe have been precisely measured in order to determine the features on the shake processes resulting from multiple electron excitations as a function of photon energy. Double-electron transitions of [1s4d], [1s4p], [1s4s], and [1s3d] are first detected. (author)

  18. Electron-capture Rates for pf-shell Nuclei in Stellar Environments and Nucleosynthesis

    Science.gov (United States)

    Suzuki, Toshio; Honma, Michio; Mori, Kanji; Famiano, Michael A.; Kajino, Toshitaka; Hidakai, Jun; Otsuka, Takaharu

    Gamow-Teller strengths in pf-shell nuclei obtained by a new shell-model Hamltonian, GXPF1J, are used to evaluate electron-capture rates in pf-shell nuclei at stellar environments. The nuclear weak rates with GXPF1J, which are generally smaller than previous evaluations for proton-rich nuclei, are applied to nucleosynthesis in type Ia supernova explosions. The updated rates are found to lead to less production of neutron-rich nuclei such as 58Ni and 54Cr, thus toward a solution of the problem of over-production of neutron-rich isotopes of iron-group nuclei compared to the solar abundance.

  19. Analysis of neonicotinoids by gas chromatography coupled to nuclide 63Ni - Electron Capture Detector - GC/ECD

    International Nuclear Information System (INIS)

    Amaral, Priscila O.; Leao, Claudio; Redigolo, Marcelo M.; Crepaldi, Caike; Bustillos, Oscar V.

    2015-01-01

    Recently, several reports have been published discussing reduction in bee population which polymerizes cultures around the world this phenomenon is known as Colony Collapse Disorder (CCD). The phenomenon describes the lack of worker honeybees in the colony despite having pups and food. The causes of this problem are unknown but there are studies that claim that reduction of population of bees is linked to poisoning through insecticides specifically neonicotinoids. Among this type of pesticide are imidacloprid (C 9 H 10 ClN 5 O 2 ), clothianidin (C 6 H 8 ClN 5 O 2 S) and thiamethoxam (C 8 H 10 ClN 5 O 3 S). This paper presents the analysis of neonicotinoids - clothianidin, imidacloprid and thiamethoxam - by the technique of gas chromatography coupled to nuclide 63 Ni electron capture detector (GC/ECD). The electron capture detector (ECD) is a gas chromatography detector that has been used for the detection of organic halogens, nitriles, nitrates and organometallic compounds. The ECD detector ionizes the analytes by the beta particles from the nuclide sources 63 Ni within carrier gas N 2 . The electrons produced in this process are collected and create a current that are amplified and generates a chromatographic peak. Methodology and details of the analysis are present in this work. (author)

  20. Influence of the Coulomb interaction in the final state on the cross section of single-electron capture by fast ions

    International Nuclear Information System (INIS)

    Novikov, N.V.; Teplova, Ya.A.

    2011-01-01

    It is shown that the Coulomb interaction of ions in the final state must be taken into account in the estimation of the cross section of electron capture by fast ions. The cross section of electron capture decreases considerably, and the dependence of the cross section on the collision energy becomes close to the experimental one if the interaction of charged particles after collision is taken into account. -- Highlights: → Coulomb interaction of ions in the final state must be taken into account. → This interaction leads to a considerable decrease in the cross section. → The dependence on energy close to the experimental one.

  1. Beam Transport Devices for the 10 kW IR Free Electron Laser

    International Nuclear Information System (INIS)

    Lawrence Dillon-Townes; Michael Bevins; David Kashy; Stephanie Slachtouski; Ronald Lassiter; George Neil; Michelle Shinn; Joseph Gubeli; Christopher Behre; David Douglas; David W. Waldman; George Biallas; Lawrence Munk; Christopher Gould

    2005-01-01

    Beam transport components for the 10kW IR Free Electron Laser (FEL) at Thomas Jefferson National Accelerator Facility (Jefferson Lab) were designed to manage (1) electron beam transport and (2) photon beam transport. An overview of the components will be presented in this paper. The electron beam transport components were designed to address RF heating, maintain an accelerator transport vacuum of 1 x 10 -8 torr, deliver photons to the optical cavity, and provide 50 kW of beam absorption during the energy recovery process. The components presented include a novel shielded bellows, a novel zero length beam clipper, a one decade differential pumping station with a 7.62 cm (3.0 inch) aperture, and a 50 kW beam dump. The photon beam transport components were designed to address the management of photons delivered by the accelerator transport. The optical cavity manages the photons and optical transport delivers the 10 kW of laser power to experimental labs. The optical cavity component presented is a unique high reflector vessel and the optical transport component presented is a turning mirror cassette

  2. Rcapture: Loglinear Models for Capture-Recapture in R

    Directory of Open Access Journals (Sweden)

    Sophie Baillargeon

    2007-04-01

    Full Text Available This article introduces Rcapture, an R package for capture-recapture experiments. The data for analysis consists of the frequencies of the observable capture histories over the t capture occasions of the experiment. A capture history is a vector of zeros and ones where one stands for a capture and zero for a miss. Rcapture can fit three types of models. With a closed population model, the goal of the analysis is to estimate the size N of the population which is assumed to be constant throughout the experiment. The estimator depends on the way in which the capture probabilities of the animals vary. Rcapture features several models for these capture probabilities that lead to different estimators for N. In an open population model, immigration and death occur between sampling periods. The estimation of survival rates is of primary interest. Rcapture can fit the basic Cormack-Jolly-Seber and Jolly-Seber model to such data. The third type of models fitted by Rcapture are robust design models. It features two levels of sampling; closed population models apply within primary periods and an open population model applies between periods. Most models in Rcapture have a loglinear form; they are fitted by carrying out a Poisson regression with the R function glm. Estimates of the demographic parameters of interest are derived from the loglinear parameter estimates; their variances are obtained by linearization. The novel feature of this package is the provision of several new options for modeling capture probabilities heterogeneity between animals in both closed population models and the primary periods of a robust design. It also implements many of the techniques developed by R. M. Cormack for open population models.

  3. Probing Protein Structure and Folding in the Gas Phase by Electron Capture Dissociation

    Science.gov (United States)

    Schennach, Moritz; Breuker, Kathrin

    2015-07-01

    The established methods for the study of atom-detailed protein structure in the condensed phases, X-ray crystallography and nuclear magnetic resonance spectroscopy, have recently been complemented by new techniques by which nearly or fully desolvated protein structures are probed in gas-phase experiments. Electron capture dissociation (ECD) is unique among these as it provides residue-specific, although indirect, structural information. In this Critical Insight article, we discuss the development of ECD for the structural probing of gaseous protein ions, its potential, and limitations.

  4. A Generalized Estimating Equations Approach to Model Heterogeneity and Time Dependence in Capture-Recapture Studies

    Directory of Open Access Journals (Sweden)

    Akanda Md. Abdus Salam

    2017-03-01

    Full Text Available Individual heterogeneity in capture probabilities and time dependence are fundamentally important for estimating the closed animal population parameters in capture-recapture studies. A generalized estimating equations (GEE approach accounts for linear correlation among capture-recapture occasions, and individual heterogeneity in capture probabilities in a closed population capture-recapture individual heterogeneity and time variation model. The estimated capture probabilities are used to estimate animal population parameters. Two real data sets are used for illustrative purposes. A simulation study is carried out to assess the performance of the GEE estimator. A Quasi-Likelihood Information Criterion (QIC is applied for the selection of the best fitting model. This approach performs well when the estimated population parameters depend on the individual heterogeneity and the nature of linear correlation among capture-recapture occasions.

  5. Contribution of vitamin K1 to the electron spin polarization in spinach photosystem I

    International Nuclear Information System (INIS)

    Rustandi, R.R.; Snyder, S.W.; Feezel, L.L.; Michalski, T.J.; Norris, J.R.; Thurnauer, M.C.; Biggins, J.

    1990-01-01

    The electron spin polarized (ESP) electron paramagnetic resonance (EPR) signal observed in spinach photosystem I (PSI) particles was examined in preparations depleted of vitamin K1 by solvent extraction and following biological reconstitution by the quinone. The ESP EPR signal was not detected in the solvent-extracted PSI sample but was restored upon reconstitution with either protonated or deuterated vitamin K1 under conditions that also restored electron transfer to the terminal PSI acceptors. Reconstitution using deuterated vitamin K1 resulted in a line narrowing of the ESP EPR signal, supporting the conclusion that the ESP EPR signals in the reconstituted samples arise from a radical pair consisting of the oxidized PSI primary donor, P700+, and reduced vitamin K1

  6. EDF: Computing electron number probability distribution functions in real space from molecular wave functions

    Science.gov (United States)

    Francisco, E.; Pendás, A. Martín; Blanco, M. A.

    2008-04-01

    Given an N-electron molecule and an exhaustive partition of the real space ( R) into m arbitrary regions Ω,Ω,…,Ω ( ⋃i=1mΩ=R), the edf program computes all the probabilities P(n,n,…,n) of having exactly n electrons in Ω, n electrons in Ω,…, and n electrons ( n+n+⋯+n=N) in Ω. Each Ω may correspond to a single basin (atomic domain) or several such basins (functional group). In the later case, each atomic domain must belong to a single Ω. The program can manage both single- and multi-determinant wave functions which are read in from an aimpac-like wave function description ( .wfn) file (T.A. Keith et al., The AIMPAC95 programs, http://www.chemistry.mcmaster.ca/aimpac, 1995). For multi-determinantal wave functions a generalization of the original .wfn file has been introduced. The new format is completely backwards compatible, adding to the previous structure a description of the configuration interaction (CI) coefficients and the determinants of correlated wave functions. Besides the .wfn file, edf only needs the overlap integrals over all the atomic domains between the molecular orbitals (MO). After the P(n,n,…,n) probabilities are computed, edf obtains from them several magnitudes relevant to chemical bonding theory, such as average electronic populations and localization/delocalization indices. Regarding spin, edf may be used in two ways: with or without a splitting of the P(n,n,…,n) probabilities into α and β spin components. Program summaryProgram title: edf Catalogue identifier: AEAJ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAJ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 5387 No. of bytes in distributed program, including test data, etc.: 52 381 Distribution format: tar.gz Programming language: Fortran 77 Computer

  7. CEBAF 200 kV Inverted Electron Gun

    International Nuclear Information System (INIS)

    Grames, J.M.; Adderley, P.A.; Clark, J.; Hansknecht, J.; Poelker, M.; Stutzman, M.L.; Suleiman, R.; Surles-Law, K.E.L.

    2011-01-01

    Two DC high voltage GaAs photoguns have been built at Jefferson Lab based on a compact inverted insulator design. One photogun provides the polarized electron beam at CEBAF and operates at 130 kV bias voltage. The other gun is used for high average current lifetime studies at a dedicated test facility and has been operated at bias voltage up to 225 kV. The advantages of higher DC voltage for CEBAF include reduced space-charge emittance growth and the potential for prolonged photocathode lifetime. However, a consequence of operating at higher voltages is the increased likelihood of field emission or breakdown, both of which are unacceptable. Highlights of the R and D studies leading toward a production 200keV GaAs photogun for CEBAF will be presented.

  8. Weak radiative decay Λ→nγ and the radiative capture reaction K-p→Σ(1385)γ

    International Nuclear Information System (INIS)

    Larson, K.D.; Noble, A.J.; Bassalleck, B.; Burkhardt, H.; Fickinger, W.J.; Hall, J.R.; Hallin, A.L.; Hasinoff, M.D.; Horvath, D.; Jones, P.G.; Lowe, J.; McIntyre, E.K.; Measday, D.F.; Miller, J.P.; Roberts, B.L.; Robinson, D.K.; Sakitt, M.; Salomon, M.; Stanislaus, S.; Waltham, C.E.; Warner, T.M.; Whitehouse, D.A.; Wolfe, D.M.

    1993-01-01

    The branching ratio for the Λ weak radiative decay Λ→nγ has been measured. Three statistically independent results from the same experiment (Brookhaven E811) are reported here. They are combined with a previously published measurement, also from Brookhaven E811, to yield a result of (Λ→nγ)/(Λ→anything)=(1.75±0.15)x10 -3 , based on 1800 events after background subtraction. This represents a factor of 75 increase in statistics over the previous world total. A comparison with recent theoretical papers shows that no existing model provides a completely satisfactory description of all data on weak radiative decays. A search is also reported for the radiative capture process K - p→Σ(1385)γ at rest. No signal was observed and an upper limit on the branching ratio of [K - p→Σ(1385)γ]/[K - p→anything] -4 (90% C.L.) was determined

  9. Phase control of the probability of electronic transitions in the non-perturbative laser field intensity

    International Nuclear Information System (INIS)

    Yokoyama, Keiichi; Sugita, Akihiro; Yamada, Hidetaka; Teranishi, Yoshiaki; Yokoyama, Atsushi

    2007-01-01

    A preparatory study on the quantum control of the selective transition K(4S 1/2 ) → K(4P J ) (J=1/2, 3/2) in intense laser field is reported. To generate high average power femtosecond laser pulses with enough field intensity, a Ti:Sapphire regenerative amplifier system with a repetition rate of 1 kHz is constructed. The bandwidth and pulse energy are shown to qualify the required values for the completely selective transition with 100% population inversion. A preliminary experiment of the selective excitation shows that the fringe pattern formed by a phase related pulse pair depends on the laser intensity, indicating that the perturbative behavior of the excitation probabilities is not valid any more and the laser intensity reaches a non-perturbative region. (author)

  10. Maximum Entropy and Probability Kinematics Constrained by Conditionals

    Directory of Open Access Journals (Sweden)

    Stefan Lukits

    2015-03-01

    Full Text Available Two open questions of inductive reasoning are solved: (1 does the principle of maximum entropy (PME give a solution to the obverse Majerník problem; and (2 isWagner correct when he claims that Jeffrey’s updating principle (JUP contradicts PME? Majerník shows that PME provides unique and plausible marginal probabilities, given conditional probabilities. The obverse problem posed here is whether PME also provides such conditional probabilities, given certain marginal probabilities. The theorem developed to solve the obverse Majerník problem demonstrates that in the special case introduced by Wagner PME does not contradict JUP, but elegantly generalizes it and offers a more integrated approach to probability updating.

  11. Electron capture in collisions of S4+ with atomic hydrogen

    Science.gov (United States)

    Stancil, P. C.; Turner, A. R.; Cooper, D. L.; Schultz, D. R.; Rakovic, M. J.; Fritsch, W.; Zygelman, B.

    2001-06-01

    Charge transfer processes due to collisions of ground state S4+(3s2 1S) ions with atomic hydrogen are investigated for energies between 1 meV u-1 and 10 MeV u-1 using the quantum mechanical molecular-orbital close-coupling (MOCC), atomic-orbital close-coupling, classical trajectory Monte Carlo (CTMC) and continuum distorted wave methods. The MOCC calculations utilize ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained with the spin-coupled valence-bond approach. A number of variants of the CTMC approach were explored, including different momentum and radial distributions for the initial state, as well as effective charge and quantum-defect models to determine the corresponding quantum state after capture into final partially stripped S3+ excited classical states. Hydrogen target isotope effects are explored and rate coefficients for temperatures between 100 and 106 K are also presented.

  12. One-electron capture and target ionization in He+-neutral-atom collisions

    International Nuclear Information System (INIS)

    Shevelko, V.P.; Tolstikhina, I.Yu.; Kato, D.; Tawara, H.; Song, M-.Y.; Yoon, J-.S.

    2009-12-01

    One-electron capture and target-ionization cross sections in collisions of He + ions with neutral atoms: He + + A → He + A + and He + + A → He + + A + + e, A = H, He(1s 2 , 1s2s), Ne, Ar, Kr, Xe, are calculated and compared with available experimental data over the broad energy range E = 0.1 keV/u - 10 MeV/u of He + ions. The role of the metastable states of neutral helium atoms in such collisions, which are of importance in plasma physics applications, is briefly discussed. The recommended cross section data for these processes are presented in a closed analytical form (nine-order polynomials) which can be used for a plasma modeling and diagnostics. (author)

  13. Absolute E3 and M2 transition probabilities for the electromagnetic decay of the I{sup {pi}}=K{sup {pi}}=8{sup -} isomeric state in {sup 132}Ce

    Energy Technology Data Exchange (ETDEWEB)

    Perkowski, J.; Andrzejewski, J.; Krol, A. [University of Lodz, Faculty of Physics and Applied Informatics, Lodz (Poland); Srebrny, J.; Kownacki, J.; Zielinska, M. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); Bruce, A.M. [University of Brighton, School of Environment and Technology, Brighton (United Kingdom); Droste, C.; Grodner, E.; Morek, T. [University of Warsaw, Nuclear Physics Division, IEP, Warsaw (Poland); Kisielinski, M. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); The Andrzej Soltan Institute for Nuclear Studies, Warsaw (Poland); Korman, A. [The Andrzej Soltan Institute for Nuclear Studies, Warsaw (Poland); Kowalczyk, M.; Mierzejewski, J. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); University of Warsaw, Nuclear Physics Division, IEP, Warsaw (Poland); Marganiec, J. [University of Lodz, Faculty of Physics and Applied Informatics, Lodz (Poland); Gesellschaft fuer Schwerionenforschung (GSI), Reactions and Nuclear Astrophysics Division, Darmstadt (Germany); Sobczak, K. [University of Lodz, Faculty of Physics and Applied Informatics, Lodz (Poland); Institute of Physics Polish Academy of Sciences, Warsaw (Poland); Trzaska, W.H. [University of Jyvaeskylae, Department of Physics, Survontie 9, P.O. Box 35, Jyvaeskylae (Finland); Helsinki Institute of Physics, Survontie 9, P.O. Box 35, Helsinki (Finland)

    2009-12-15

    The decay of the I{sup {pi}}=K{sup {pi}}=8{sup -} isomeric state at 2340keV in {sup 132}Ce has been investigated in the {sup 120}Sn({sup 16}O,4n){sup 132}Ce reaction. The measurements were carried out in e-{gamma} and {gamma}-{gamma} coincidence modes using an electron spectrometer coupled to the OSIRIS II gamma-ray array at the Heavy Ion Laboratory of the University of Warsaw. Experimentally obtained internal conversion coefficients for the 8{sup -}{yields}6{sup +} and 8{sup -}{yields}5{sup +} transitions allowed the multipolarities, mixing ratios, reduced transition probabilities and hindrance factors to be determined. (orig.)

  14. Shifts in electron capture to the continuum at low collision energies: Enhanced role of target postcollision interactions

    International Nuclear Information System (INIS)

    Shah, M. B.; McGrath, C.; Luna, H.; Crothers, D.S.F.; O'Rourke, S.F.C.; Gilbody, H.B.; Illescas, Clara; Riera, A.; Pons, B.

    2003-01-01

    Measurements of electron velocity distributions emitted at 0 deg. for collisions of 10- and 20-keV H + incident ions on H 2 and He show that the electron capture to the continuum cusp formation, which is still possible at these low impact energies, is shifted to lower momenta than its standard position (centered on the projectile velocity), as recently predicted. Classical trajectory Monte Carlo calculations reproduce the observations remarkably well, and indicate that a long-range residual interaction of the electron with the target ion after ionization is responsible for the shifts, which is a general effect that is enhanced at low nuclear velocities

  15. Electron scavenging in ethylene glycol-water glass at 4 and 77 K: scavenging of trapped vs mobile electrons. [. gamma. -rays, x radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, D P; Kevan, L [Wayne State Univ., Detroit, Mich. (USA). Dept. of Chemistry; Steen, H B

    1976-01-01

    Electron scavenging efficiencies have been measured at 77 and 4 K in ethylene glycol-water glass for the following scavengers which span a 250-fold range of scavenger efficiencies at 77 K: HCl, NaNO/sub 3/ and K/sub 2/Cr0/sub 4/. The range of scavenging efficiencies decreases to 62 at 4 K with the largest relative change occurring for the less efficient scavengers. These results are suggested to be most consistent with a model in which scavenging occurs by tunneling from shallowly and deeply trapped electrons at 4 and 77 K, respectively.

  16. Relativistic electron beam interaction and $K_{\\alpha}$-generation in solid targets

    CERN Document Server

    Fill, E; Eder, D; Eidmann, K; Saemann, A

    1999-01-01

    When fs laser pulses interact with solid surfaces at intensities I lambda /sup 2/ >10/sup 18/ W/cm/sup 2/ mu m/sup 2/, collimated relativistic electron beams are generated. These electrons can be used for producing intense X-radiation (bremsstrahlung or K/sub alpha /) for pumping an innershell X-ray laser. The basic concept of such a laser involves the propagation of the electron beam in a material which converts electron energy into appropriate pump photons. Using the ATLAS titanium-sapphire laser at Max-Planck-Institut fur Quantenoptik, we investigate the generation of hot electrons and of characteristic radiation in copper. The laser (200 mJ/130 fs) is focused by means of an off-axis parabola to a diameter of about 10 mu m. By varying the position of the focus, we measure the copper K/sub alpha /-yield as a function of intensity in a range from 10/sup 15/ to 2 x 10/sup 18/ W/cm/sup 2/ while keeping the laser pulse energy constant. Surprisingly, the highest emission is obtained at an intensity of about 10/s...

  17. Improvement of the 400 kV linac electron source of AmPS

    International Nuclear Information System (INIS)

    Kroes, F.B.; Beuzekom, M.G. van; Dobbe, N.J.; Es, J.T. van; Jansweijer, P.P.M.; Kruijer, A.H.; Luigjes, G.; Sluijk, T.G.B.

    1992-01-01

    The installation of the 900 MeV Amsterdam Pulse Stretcher is nearly completed and its commissioning will start Spring 1992. The existing linac MEA will inject electrons in the AmPS ring. The linacs peak current will be increased from 20 to 80 mA. This requires modification of the 400 kV low emittance gun which now will deliver a peak current of maximum 400 mA instead of 100 mA at a pulse width of 2.1 μsec. The fourfold increase of the peakcurrent is obtained by doubling both the gun perveance (new gun part) and the pulsed extractor voltage. After chopping and pre-bunching more than 80 mA will be available for acceleration in MEA. To obtain optimum beam quality over this increased current range the hot deck electronics, operating at -400 kV, has been exchanged by a state of the art fast high voltage FET switching supply. The increased space charge forces in the beam require stronger electro-static focusing in the first electrostatic gap to define the beam diameter at the gun exit. This is accomplished with a 25 kV controlled power supply. A build in microprocessor, coupled to the local computer by optical fibers, is used to monitor and control the gun parameters. The 5kV gun extractor voltage pulse shape can be monitored by means of an analog fibre transducer with build in calibration. Finally, in order to improve the energy stability of the accelerated electrons a serial electron-tube stabilizer was added to the 400 kV DC power supply. A supply stability of 2. 10 -5 has been achieved. (author). 4 refs.; 6 figs

  18. Atomic physics at the Argonne PII ECR [electron cyclotron resonance] Ion Source

    International Nuclear Information System (INIS)

    Dunford, R.W.; Berry, H.G.; Billquist, P.J.; Pardo, R.C.; Zabransky, B.J.; Bakke, E.; Groeneveld, K.O.; Hass, M.; Raphaelian, M.L.A.

    1987-01-01

    An atomic physics beam line has been set up at the Argonne PII ECR Ion Source. The source is on a 350-kV high-voltage platform which is a unique feature of particular interest in work on atomic collisions. We describe our planned experimental program which includes: measurement of state-selective electron-capture cross sections, studies of doubly-excited states, precision spectroscopy of few-electron ions, tests of quantum electrodynamics, and studies of polarization transfer using optically pumped polarized alkali targets. The first experiments will be measurements of cross sections for electron capture into specific nl subshells in ion-atom collisions. Our method is to observe the characteristic radiation emitted after capture using a VUV spectrometer. Initial data from these experiments are presented. 12 refs., 4 figs

  19. Energy-filtered real- and k-space secondary and energy-loss electron imaging with Dual Emission Electron spectro-Microscope: Cs/Mo(110)

    Energy Technology Data Exchange (ETDEWEB)

    Grzelakowski, Krzysztof P., E-mail: k.grzelakowski@opticon-nanotechnology.com

    2016-05-15

    Since its introduction the importance of complementary k{sub ||}-space (LEED) and real space (LEEM) information in the investigation of surface science phenomena has been widely demonstrated over the last five decades. In this paper we report the application of a novel kind of electron spectromicroscope Dual Emission Electron spectroMicroscope (DEEM) with two independent electron optical channels for reciprocal and real space quasi-simultaneous imaging in investigation of a Cs covered Mo(110) single crystal by using the 800 eV electron beam from an “in-lens” electron gun system developed for the sample illumination. With the DEEM spectromicroscope it is possible to observe dynamic, irreversible processes at surfaces in the energy-filtered real space and in the corresponding energy-filtered k{sub ǁ}-space quasi-simultaneously in two independent imaging columns. The novel concept of the high energy electron beam sample illumination in the cathode lens based microscopes allows chemically selective imaging and analysis under laboratory conditions. - Highlights: • A novel concept of the electron sample illumination with “in-lens” e- gun is realized. • Quasi-simultaneous energy selective observation of the real- and k-space in EELS mode. • Observation of the energy filtered Auger electron diffraction at Cs atoms on Mo(110). • Energy-loss, Auger and secondary electron momentum microscopy is realized.

  20. Characteristic length of the knotting probability revisited

    International Nuclear Information System (INIS)

    Uehara, Erica; Deguchi, Tetsuo

    2015-01-01

    We present a self-avoiding polygon (SAP) model for circular DNA in which the radius of impermeable cylindrical segments corresponds to the screening length of double-stranded DNA surrounded by counter ions. For the model we evaluate the probability for a generated SAP with N segments having a given knot K through simulation. We call it the knotting probability of a knot K with N segments for the SAP model. We show that when N is large the most significant factor in the knotting probability is given by the exponentially decaying part exp(−N/N K ), where the estimates of parameter N K are consistent with the same value for all the different knots we investigated. We thus call it the characteristic length of the knotting probability. We give formulae expressing the characteristic length as a function of the cylindrical radius r ex , i.e. the screening length of double-stranded DNA. (paper)

  1. Electronic Procedures for Medical Operations

    Science.gov (United States)

    2015-01-01

    Electronic procedures are replacing text-based documents for recording the steps in performing medical operations aboard the International Space Station. S&K Aerospace, LLC, has developed a content-based electronic system-based on the Extensible Markup Language (XML) standard-that separates text from formatting standards and tags items contained in procedures so they can be recognized by other electronic systems. For example, to change a standard format, electronic procedures are changed in a single batch process, and the entire body of procedures will have the new format. Procedures can be quickly searched to determine which are affected by software and hardware changes. Similarly, procedures are easily shared with other electronic systems. The system also enables real-time data capture and automatic bookmarking of current procedure steps. In Phase II of the project, S&K Aerospace developed a Procedure Representation Language (PRL) and tools to support the creation and maintenance of electronic procedures for medical operations. The goal is to develop these tools in such a way that new advances can be inserted easily, leading to an eventual medical decision support system.

  2. Resonance enhancement of neutrinoless double electron capture

    International Nuclear Information System (INIS)

    Krivoruchenko, M.I.; Simkovic, Fedor; Frekers, Dieter; Faessler, Amand

    2011-01-01

    The process of neutrinoless double electron (0νECEC) capture is revisited for those cases where the two participating atoms are nearly degenerate in mass. The theoretical framework is the formalism of an oscillation of two atoms with different total lepton number (and parity), one of which can be in an excited state so that mass degeneracy is realized. In such a case and assuming light Majorana neutrinos, the two atoms will be in a mixed configuration with respect to the weak interaction. A resonant enhancement of transitions between such pairs of atoms will occur, which could be detected by the subsequent electromagnetic de-excitation of the excited state of the daughter atom and nucleus. Available data of atomic masses, as well as nuclear and atomic excitations are used to select the most likely candidates for the resonant transitions. Assuming an effective mass for the Majorana neutrino of 1 eV, some half-lives are predicted to be as low as 10 22 years in the unitary limit. It is argued that, in order to obtain more accurate predictions for the 0νECEC half-lives, precision mass measurements of the atoms involved are necessary, which can readily be accomplished by today's high precision Penning traps. Further advancements also require a better understanding of high-lying excited states of the final nuclei (i.e. excitation energy, angular momentum and parity) and the calculation of the nuclear matrix elements.

  3. Electron diffraction using ultrafast electron bunches from a laser-wakefield accelerator at kHz repetition rate

    Science.gov (United States)

    He, Z.-H.; Thomas, A. G. R.; Beaurepaire, B.; Nees, J. A.; Hou, B.; Malka, V.; Krushelnick, K.; Faure, J.

    2013-02-01

    We show that electron bunches in the 50-100 keV range can be produced from a laser wakefield accelerator using 10 mJ, 35 fs laser pulses operating at 0.5 kHz. It is shown that using a solenoid magnetic lens, the electron bunch distribution can be shaped. The resulting transverse and longitudinal coherence is suitable for producing diffraction images from a polycrystalline 10 nm aluminum foil. The high repetition rate, the stability of the electron source, and the fact that its uncorrelated bunch duration is below 100 fs make this approach promising for the development of sub-100 fs ultrafast electron diffraction experiments.

  4. Electron diffraction using ultrafast electron bunches from a laser-wakefield accelerator at kHz repetition rate

    Energy Technology Data Exchange (ETDEWEB)

    He, Z.-H.; Thomas, A. G. R.; Nees, J. A.; Hou, B.; Krushelnick, K. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48106-2099 (United States); Beaurepaire, B.; Malka, V.; Faure, J. [Laboratoire d' Optique Appliquee, ENSTA-CNRS-Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France)

    2013-02-11

    We show that electron bunches in the 50-100 keV range can be produced from a laser wakefield accelerator using 10 mJ, 35 fs laser pulses operating at 0.5 kHz. It is shown that using a solenoid magnetic lens, the electron bunch distribution can be shaped. The resulting transverse and longitudinal coherence is suitable for producing diffraction images from a polycrystalline 10 nm aluminum foil. The high repetition rate, the stability of the electron source, and the fact that its uncorrelated bunch duration is below 100 fs make this approach promising for the development of sub-100 fs ultrafast electron diffraction experiments.

  5. Determination of DDTs and PCBs by capillary gas chromatography and electron capture detection

    International Nuclear Information System (INIS)

    1988-01-01

    This reference method deals with the determination of DDTs and PCBs in marine environmental samples using high resolution gas chromatography. Several other halogenated pesticides and other electron capturing organic compounds may be present in samples and many of these may also be determined by this method. Not all electron capturing residues will be resistant to all of the clean up procedures described here for the analysis of DTTs and PCBs. Therefore, additional information on the stability of some common pesticides using this methodology is also provided. The high separation power of open tubular (''capillary'') columns allows the identification and quantification of many compounds in the complex mixtures occurring in environmental samples. This manual provides information on the theoretical and practical aspects of the use of these high resolution columns for the analysis of DDTs and PCBs in environmental samples. The qualitative and quantitative method can be applied to any sample type (aerosol/vapour, water, particulates, biota, etc.) provided that suitable cleaned-up extracts dissolved in n-hexane are available for injection into the GC system. For example, methods for obtaining these cleaned-up sample extracts from marine organisms are described in detail in UNEP Reference Method no. 14 and for sediments in No. 17. The change in the field of application by analysing by capillary rather than packed columns may be less dramatic for DDTs. However, with the increased separation, the possibilities of inaccurate analysis resulting from overlap with interfering compounds is reduced. 7 refs, 1 fig., 3 tabs

  6. The problem of latent attentional capture: Easy visual search conceals capture by task-irrelevant abrupt onsets.

    Science.gov (United States)

    Gaspelin, Nicholas; Ruthruff, Eric; Lien, Mei-Ching

    2016-08-01

    Researchers are sharply divided regarding whether irrelevant abrupt onsets capture spatial attention. Numerous studies report that they do and a roughly equal number report that they do not. This puzzle has inspired numerous attempts at reconciliation, none gaining general acceptance. The authors propose that abrupt onsets routinely capture attention, but the size of observed capture effects depends critically on how long attention dwells on distractor items which, in turn, depends critically on search difficulty. In a series of spatial cuing experiments, the authors show that irrelevant abrupt onsets produce robust capture effects when visual search is difficult, but not when search is easy. Critically, this effect occurs even when search difficulty varies randomly across trials, preventing any strategic adjustments of the attentional set that could modulate probability of capture by the onset cue. The authors argue that easy visual search provides an insensitive test for stimulus-driven capture by abrupt onsets: even though onsets truly capture attention, the effects of capture can be latent. This observation helps to explain previous failures to find capture by onsets, nearly all of which used an easy visual search. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  7. Electron capture in collisions of ? with H and ? with C

    Science.gov (United States)

    Stancil, P. C.; Gu, J.-P.; Havener, C. C.; Krstic, P. S.; Schultz, D. R.; Kimura, M.; Zygelman, B.; Hirsch, G.; Buenker, R. J.; Bannister, M. E.

    1998-08-01

    A comprehensive theoretical and experimental study of electron capture in collisions of 0953-4075/31/16/017/img15 with H and 0953-4075/31/16/017/img16 with C extending over the energy range 0953-4075/31/16/017/img17 to 0953-4075/31/16/017/img18 is presented. A variety of theoretical approaches were used including those based on quantal molecular-orbital close-coupling (MOCC), multielectron hidden crossings (MEHC), quantal decay and classical trajectory Monte Carlo techniques. Radiative charge transfer cross sections were computed using the optical potential/distorted wave (OPDW) and fully quantal (FQ) approaches. The MOCC, OPDW and FQ calculations incorporated ab initio potentials, nonadiabatic coupling matrix elements and transition moments computed at the configuration-interaction level. Ab initio potential surfaces in the plane of complex internuclear distance were obtained for the MEHC calculations. Merged-beam measurements were performed between 0953-4075/31/16/017/img19 and 0953-4075/31/16/017/img20 for the 0953-4075/31/16/017/img21 collision system. Diagnostics of the 0953-4075/31/16/017/img15 beam with a crossed electron beam could find no presence of a 0953-4075/31/16/017/img15 metastable component. The current results, in conjunction with previous measurements, are used to deduce a set of recommended cross sections.

  8. Design and development of 3 MeV, 30 kW DC industrial electron accelerator at Electron Beam Centre, Kharghar

    International Nuclear Information System (INIS)

    Mittal, K.C.; Nanu, K.; Jain, A.

    2006-01-01

    High power electron beam accelerators are becoming an important tool for industrial radiation process applications. Keeping this in mind, a 3 MeV, 10 mA, 30 kW DC industrial electron accelerator has been designed and is in advanced stage of development at Electron Beam Center, Kharghar, Navi Mumbai. The operating range of this accelerator is 1 MeV to 3 MeV with maximum beam current of 10 mA. Electron beam at 5 keV is generated in electron gun with LaB 6 cathode and is injected into accelerating column at a vacuum of 10 -7 torr. After acceleration the beam is scanned and taken out in air through a 100 cm X 7 cm titanium window for radiation processing applications. The high voltage accelerating power supply is based on a capacitive coupled parallel fed voltage multiplier scheme operating at 120 kHz. A 50 kW oscillator feeds power to high voltage multiplier column. The electron gun, accelerating column and high voltage multiplier column are housed in accelerator tank filled with SF 6 gas insulation at 6 kg/cm 2 . The accelerator is located in a RCC building with product conveyor for handling products. A central computerized control system is adopted for operation of the accelerator. Accelerator is in the advance stage of commissioning. Many of the subsystems have been commissioned and tested. This paper describes the design details and current status of the accelerator and various subsystems. (author)

  9. New limit on the half-life of 78Kr with respect to the 2K(2ν)-capture decay mode

    International Nuclear Information System (INIS)

    Gavriljuk, Ju.M.; Kuzminov, V.V.; Osetrova, N.Ya.; Ratkevich, S.S.

    2000-01-01

    The features of data accumulated for 1817 h in an experimental search for the 2K(2ν)-capture mode of 78 Kr decay are discussed. A new limit on the half-life for this decay is found: T 1sol2 ≥ 2.3 x 10 20 yr (at a 90% C.L.)

  10. Population of Rydberg states by electron capture in fast-ion--atom collisions

    International Nuclear Information System (INIS)

    Burgdoerfer, J.; Dube, L.J.

    1985-01-01

    The l,m-substate distribution in low-lying Rydberg manifolds (nroughly-equal10) following electron capture H + +H(1s)→H(n)+H + is calculated at high velocities (v>1 a.u.) in the continuum-distorted-wave (CDW) approximation. The standard CDW approximation is modified to account for final-state Stark mixing of the Rydberg manifold in the exit channel using the post-collision-interaction model. The influence of multiple-scattering contributions is analyzed and comparison is made with sigma/sub l/m predicted by the Born approximation. We find that the double-scattering contribution, closely connected with the classical Thomas process, becomes visible in the CDW approximation at surprisingly low nonasymptotic velocities

  11. Electron capture rates in stars studied with heavy ion charge exchange reactions

    Science.gov (United States)

    Bertulani, C. A.

    2018-01-01

    Indirect methods using nucleus-nucleus reactions at high energies (here, high energies mean ~ 50 MeV/nucleon and higher) are now routinely used to extract information of interest for nuclear astrophysics. This is of extreme relevance as many of the nuclei involved in stellar evolution are short-lived. Therefore, indirect methods became the focus of recent studies carried out in major nuclear physics facilities. Among such methods, heavy ion charge exchange is thought to be a useful tool to infer Gamow-Teller matrix elements needed to describe electron capture rates in stars and also double beta-decay experiments. In this short review, I provide a theoretical guidance based on a simple reaction model for charge exchange reactions.

  12. Electron capture by multicharged ions from hydrogen atoms at eV energies

    International Nuclear Information System (INIS)

    Havener, C.C.; Nesnidal, M.P.; Porter, M.R.; Phaneuf, R.A.

    1990-01-01

    To quantitatively study electron capture during collisions of multiply charged ions with neutral atoms at near-thermal energies, keV-energy multicharged ion beams are merged with ground-state beams of H or D atoms of chosen velocity such that collisions in the relative energy range 1--1000 eV/amu result. Recent data for O 3+ , O 4+ + H(D) are presented and compared with theoretical predictions. Recently completed modifications to the apparatus are described that will provide a significant improvement in signal-to-background and angular collection. These improvements will allow measurements to be extended to lower energies, where effects due to the ion-induced dipole attraction may be evident

  13. K-intercalated carbon systems: Effects of dimensionality and substrate

    KAUST Repository

    Kaloni, Thaneshwor P.

    2012-06-01

    Density functional theory is employed to investigate the electronic properties of K-intercalated carbon systems. Young\\'s modulus indicates that the intercalation increases the intrinsic stiffness. For K-intercalated bilayer graphene on SiC(0001) the Dirac cone is maintained, whereas a trilayer configuration exhibits a small splitting at the Dirac point. Interestingly, in contrast to many other intercalated carbon systems, the presence of the SiC(0001) substrate does not suppress but rather enhances the charge carrier density. Reasonably high values are found for all systems, the highest carrier density for the bilayer. The band structure and electron-phonon coupling of free-standing K-intercalated bilayer graphene points to a high probability for superconductivity in this system. © 2012 Europhysics Letters Association.

  14. Effect of spin-orbit coupling on the wave vector and spin dependent transmission probability for the GaN/AlGaN/GaN heterostructure

    International Nuclear Information System (INIS)

    Li, M; Zhao, Z B; Fan, L B

    2015-01-01

    The effect of the Rashba and Dresselhaus spin–orbit coupling (SOC) on the transmission of electrons through the GaN/AlGaN/GaN heterostructure is studied. It is found that the Dresselhaus SOC causes the evident dependence of the transmission probability on the spin polarization and the in-plane wave vector of electrons, and also induces evident spin splitting of the resonant peaks in the (E z -k) plane. Because the magnitude of the Rashba SOC is relatively small, its effect on the transmission of electrons is much less. As k increases, the peaks of transmission probability for spin-up electrons (T + ) shift to a higher energy region and increase in magnitude, while the peaks of transmission probability for spin-down electrons (T − ) shift to a lower energy region and decrease in magnitude. The polarization efficiency (P) is found to peak at the resonant energies and increases with the in-plane wave vector. Moreover, the built-in electric field caused by the spontaneous and piezoelectric polarization can increase the amplitude of P. Results obtained here are helpful for the efficient spin injection into the III-nitride heterostructures by nonmagnetic means from the device point of view. (paper)

  15. Positronium formation at low temperatures: The role of trapped electrons

    DEFF Research Database (Denmark)

    Hirade, T.; Maurer, F.H.J.; Eldrup, Morten Mostgaard

    2000-01-01

    Measurements have been carried out of electron spin densities (by electron spin resonance technique) and positronium (Ps) formation probability as functions of Co-60 gamma-irradiation dose in poly(methyl methacrylate) and linear poly(ethylene) at 77 K. We observe a linear relationship between...

  16. Gadolinium neutron capture therapy

    International Nuclear Information System (INIS)

    Akine, Yasuyuki; Tokita, Nobuhiko; Tokuuye, Koichi; Satoh, Michinao; Churei, Hisahiko

    1993-01-01

    Gadolinium neutron capture therapy makes use of photons and electrons produced by nuclear reactions between gadolinium and lower-energy neutrons which occur within the tumor. The results of our studies have shown that its radiation effect is mostly of low LET and that the electrons are the significant component in the over-all dose. The dose from gadolinium neutron capture reactions does not seem to increase in proportion to the gadolinium concentration, and the Gd-157 concentration of about 100 μg/ml appears most optimal for therapy. Close contact between gadolinium and the cell is not necessarily required for cell inactivation, however, the effect of electrons released from intracellular gadolinium may be significant. Experimental studies on tumor-bearing mice and rabbits have shown that this is a very promising modality though further improvements in gadolinium delivery to tumors are needed. (author)

  17. Kilo-electron-volt neutron capture cross sections of the krypton isotopes

    International Nuclear Information System (INIS)

    Walter, G.; Leugers, B.; Kappeler; Bao, Z.Y.; Reffo, G.; Fabbri, F.

    1986-01-01

    The neutron capture cross sections of the stable krypton isotopes were determined in the energy interval from 4 to 250 keV using a C/sub 6/D/sub 6/-detector system in conjunction with the time-of-flight technique. The energy resolution of the measurement was 4% at 20 keV and 6% at 100 keV, and the experimental uncertainties were typically 6 to 10%. The measurements were complemented by statistical model calculations of all krypton isotopes in the mass range 78 < A < 86 to also obtain reliable cross sections for the unstable nuclei /sup 79,81,85/Kr. These calculations were based on local systematics for all relevant parameters, and the results were estimated to show uncertainties of 20 to 25%. Maxwellian average cross sections were calculated for kT=30 keV

  18. Seeing with electrons

    International Nuclear Information System (INIS)

    Nellist, P.

    2006-01-01

    Commercially available lens correctors are extending the reach of electron microscopes to unprecedented atomic scales, as Peter Nellist describes. The electron microscope was invented in 1933 and is based on the principle that electrons have a wavelength that is inversely proportional to their momentum. There are two basic types: transmission electron microscopes and scanning electron microscopes, plus a hybrid of the two. The lenses in an electron microscope are provided by electromagnetic fields, but they suffer from spherical aberration. The addition of octupole and quadrupole corrector fields has improved the resolution of the electron microscope to better than 0.1 nm in the last decade. The next step is to correct for chromatic aberration, after which the resolution of the microscope will probably be limited by the size of the atom itself. (U.K.)

  19. Experimental transition probabilities for several spectral lines arising from the 5d10 6s{8s, 7p, 5f, 5g} electronic configurations of Pb III

    International Nuclear Information System (INIS)

    Alonso-Medina, A.

    2010-01-01

    Transition probabilities for 30 spectral lines, arising from the 5d 10 6s{8s, 7p, 5f, 5g} electronic configurations of Pb III (20 measured for the first time), have been experimentally determined from measurements of emission line intensities in a plasma lead induced by ablation with a Nd:YAG laser. The line intensities were obtained with the target placed in molecular argon at 6 Torr, recorded at a 400 ns delay from the laser pulse, which provides appropriate measurement conditions, and analysed between 200 and 700 nm. They are measured when the plasma reaches local thermodynamic equilibrium (LTE). The plasma under study had an electron temperature (T) of 21,400 K and an electron number density (N e ) of 7x10 16 cm -3 . The influence of self-absorption has been estimated for every line, and plasma homogeneity has been checked. The values obtained were compared with previous experimental values and theoretical estimates where possible.

  20. Electron temperature fluctuation in the HT-7 tokamak plasma observed by electron cyclotron emission imaging

    International Nuclear Information System (INIS)

    Xiao-Yuan, Xu; Jun, Wang; Yi, Yu; Yi-Zhi, Wen; Chang-Xuan, Yu; Wan-Dong, Liu; Bao-Nian, Wan; Xiang, Gao; Luhmann, N. C.; Domier, C. W.; Wang, Jian; Xia, Z. G.; Shen, Zuowei

    2009-01-01

    The fluctuation of the electron temperature has been measured by using the electron cyclotron emission imaging in the Hefei Tokamak-7 (HT-7) plasma. The electron temperature fluctuation with a broadband spectrum shows that it propagates in the electron diamagnetic drift direction, and the mean poloidal wave-number k-bar θ is calculated to be about 1.58 cm −1 , or k-bar θρ s thickapprox 0.34. It indicates that the fluctuation should come from the electron drift wave turbulence. The linear global scaling of the electron temperature fluctuation with the gradient of electron temperature is consistent with the mixing length scale qualitatively. Evolution of spectrum of the fluctuation during the sawtooth oscillation phases is investigated, and the fluctuation is found to increase with the gradient of electron temperature increasing during most phases of the sawtooth oscillation. The results indicate that the electron temperature gradient is probably the driver of the fluctuation enhancement. The steady heat flux driven by electron temperature fluctuation is estimated and compared with the results from power balance estimation. (fluids, plasmas and electric discharges)

  1. Electron addition to alkyl cobalamins, coenzyme B/sub 12/ and vitamin B/sub 12/. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Rao, D N.R.; Symons, M C.R. [Leicester Univ. (UK). Dept. of Chemistry

    1983-01-01

    Exposure of dilute solutions of methyl and ethyl cobalamins and coenzyme B/sub 12/ in dilute solutions (D/sub 2/O+CD/sub 3/OD) to /sup 60/Co ..gamma..-rays at 77 K gave a single broad feature in the free-spin region assigned to electron-capture species with the excess electron largely confined to a ..pi..* corrin orbital. On warming above 77 K the methyl derivative gave a novel species with spectral features characteristic of an unpaired electron in the Co(dsub(x/sup 2/-y/sup 2/)) orbital. The other two substrates gave spectra due to Cosup(II)Bsub(12r) both on warming and after photolyses with visible light. The acetyl derivative gave an electron-capture species whose e.s.r. spectrum was characteristic of an electron in the Co(dsub(z/sup 2/)) orbital, which on warming above 77 K changed to the normal Cosup(II)Bsub(12r) spectrum. The cyano derivative (vitamin B/sub 12/) gave electron addition into the Co(dsub(z/sup 2/)) orbital, as evidenced by the large hyperfine coupling to /sup 13/C from /sup 13/CN ligands. On annealing, cyanide ions were lost irreversibly, Bsub(12r) being detected by e.s.r. spectroscopy. In contrast, the dicyano derivative on electron addition at 77 K gave a species containing only one /sup 13/CN ligand. Hence in this case one CN/sup -/ ligand was lost at 77 K, with no return of the dimethylbenzimidazole ligand. These results are discussed in terms of a new mechanism for electron-addition to alkyl cobalamins.

  2. Single-electron-capture processes in collisions of He2+, Liq+ (q=1,2,3), C6+, and O8+ ions with helium

    International Nuclear Information System (INIS)

    Samanta, R.; Purkait, M.; Mandal, C. R.

    2011-01-01

    Cross sections for single-electron capture in collisions of He 2+ , Li q+ (q = 1,2,3), C 6+ , and O 8+ ions with helium atoms at incident energy ranging from 50 to 5000 keV/amu have been calculated in the framework of four-body boundary-corrected continuum intermediate state (BCCIS-4B) approximation in both prior and post forms. In this formalism, distortion in the final channel related to the Coulomb continuum states of the projectile ion and the active electron in the field of residual target ion are included. In all cases, total single-electron-capture cross sections have been calculated by summing over all contributions up to n = 3 shells and subshells, respectively. It has been observed that the contribution of the capture cross section into the excited states is significant for asymmetric collision (Z P >Z T ) and is insignificant for symmetric collision. Numerical results for the total cross sections show good agreement with the available experimental findings, particularly in the post form. Post-prior discrepancy has been found to be within 30% except for Li + + He interactions below 150 keV/amu.

  3. Simulating satellite observations of 100 kHz radio waves from relativistic electron beams above thunderclouds

    OpenAIRE

    M. Füllekrug; C. Hanuise; M. Parrot

    2010-01-01

    Relativistic electron beams above thunderclouds emit 100 kHz radio waves which illuminate the Earth's atmosphere and near-Earth space. This contribution aims to clarify the physical processes which are relevant for the spatial spreading of the radio wave energy below and above the ionosphere and thereby enables simulating satellite observations of 100 kHz radio waves from relativistic electron beams above thunderclouds. The simulation uses the DEMETER satellite which observes 100 kHz ...

  4. Calibration of radionuclides with decay trough beta emission or electron capture by liquid scintillation technique

    International Nuclear Information System (INIS)

    Loureiro, Jamir dos Santos

    2000-02-01

    In this work is reported a methodology a methodology for pure beta and electron capture radionuclides standardization, suing liquid scintillation technique. In this sense the CIEMAT/NIST method, recently utilized by international laboratories, was implemented and the lack in the Laboratorio Nacional das Radiacoes Ionizantes - LNMRI, of the Comissao Nacional de Energia Nuclear - CNEN, for adequate methodology to standardize this kind if radionuclides was filled, fact that was not present with alpha and gamma radionuclides. The implementation procedure evaluation was provided by concentration activity determination of the following radionuclides: 14 C and 90 Sr, pure beta emitters; 55 Fe, electron capture decay; 204 Tl, electron capture and beta decay and 60 Co, beta-gamma emitter. In this way, a careful analysis of the implementation procedure with these radionuclides types, ranging on a broad energy spectral, was possible. To check the calibration results, intercomparisons among our measurements of these radionuclides and the reference values of the CIEMAT/Spain laboratory were provided. To check the calibration results, intercomparisons among our measurements of these radionuclides and the reference values of the CIEMAT/Spain laboratory were provided. Besides this intercomparisons, one was provided with a 204 Tl solution, utilized in the international comparison recently promoted by BIPM, and another one with a 60 C solution calibrated in LNMRI/CNEN previously by a relative calibration system, with a well type pressurized ionization chamber, and an absolute beta-gamma coincidence system, with a pill-box type proportional counter 4 π geometry, coupled with a scintillator system with a sodium iodide cristal of 4x4 inches. The comparisons among LNMRI/CNEN results and the reference values, showed a small deviation of 1,32% for 14 C, 0,40% for 60 Co, 1,12% for 55 Fe, 0,10% for 90 Sr and 0,73% for 204 Tl. For the BIPM solution the deviation was 0,46% and for 60 Co

  5. On the shake-off probability for atomic systems

    Energy Technology Data Exchange (ETDEWEB)

    Santos, A.C.F., E-mail: toniufrj@gmail.com [Instituto de Física, Universidade Federal do Rio de Janeiro, P.O. Box 68528, 21941-972 Rio de Janeiro, RJ (Brazil); Almeida, D.P. [Departamento de Física, Universidade Federal de Santa Catarina, 88040-900 Florianópolis (Brazil)

    2016-07-15

    Highlights: • The scope is to find the relationship among SO probabilities, Z and electron density. • A scaling law is suggested, allowing us to find the SO probabilities for atoms. • SO probabilities have been scaled as a function of target Z and polarizability. - Abstract: The main scope in this work has been upon the relationship between shake-off probabilities, target atomic number and electron density. By comparing the saturation values of measured double-to-single photoionization ratios from the literature, a simple scaling law has been found, which allows us to predict the shake-off probabilities for several elements up to Z = 54 within a factor 2. The electron shake-off probabilities accompanying valence shell photoionization have been scaled as a function of the target atomic number, Z, and polarizability, α. This behavior is in qualitative agreement with the experimental results.

  6. k-Space imaging of anisotropic 2D electron gas in GaN/GaAlN high-electron-mobility transistor heterostructures

    OpenAIRE

    Lev, L. L.; Maiboroda, I. O.; Husanu, M. -A.; Grichuk, E. S.; Chumakov, N. K.; Ezubchenko, I. S.; Chernykh, I. A.; Wang, X.; Tobler, B.; Schmitt, T.; Zanaveskin, M. L.; Valeyev, V. G.; Strocov, V. N.

    2018-01-01

    Nanostructures based on buried interfaces and heterostructures are at the heart of modern semiconductor electronics as well as future devices utilizing spintronics, multiferroics, topological effects and other novel operational principles. Knowledge of electronic structure of these systems resolved in electron momentum k delivers unprecedented insights into their physics. Here, we explore 2D electron gas formed in GaN/AlGaN high-electron-mobility transistor (HEMT) heterostructures with an ult...

  7. Intermolecular effects on the radiogenic formation of electron-capture phosphorus-centered radicals. A single-crystal ESR study of diastereoisomeric precursors

    Energy Technology Data Exchange (ETDEWEB)

    Aagaard, O.M.; Janssen, R.A.J.; de Waal, B.F.M.; Buck, H.M. (Eindhoven Univ. of Technology (Netherlands))

    1990-01-31

    ESR experiments on X-irradiated single crystals of the 2R,4S,5R and 2S,4S,5R diastereoisomers of 2-chloro-3,4-dimethyl-5-phenyl-1,3,2-oxazaphospholidine 2-sulfide reveal that the yield of radiogenic electron-capture reactions in the solid state strongly depends on intermolecular interactions in the crystal. In the present case a high yield of P-Cl three-electron-bond phosphoranyl radical anions is found in crystals of the 2R,4S,5R isomer, whereas no radical formation can be detected for the 2S,4S,5R isomer. An analysis of nonbonded interactions with neighboring molecules reveals that the geometry relaxation necessary for the radical stabilization is easily accommodated in crystals of the 2R,4S,SR isomer but not in the 2S,4S,5R isomer, explaining the observed difference in electron-capture efficiency. Experiments on radical formation in a MeTHF host matrix give further insight into the importance of the environment on radiogenic radical formation. The possible concurrent effect of the matrix on the electronic configuration and spin density distribution of the resulting phosphoranyl radical is discussed.

  8. Intermolecular effects on the radiogenic formation of electron-capture phosphorus-centered radicals. A single-crystal ESR study of diastereoisomeric precursors

    International Nuclear Information System (INIS)

    Aagaard, O.M.; Janssen, R.A.J.; de Waal, B.F.M.; Buck, H.M.

    1990-01-01

    ESR experiments on X-irradiated single crystals of the 2R,4S,5R and 2S,4S,5R diastereoisomers of 2-chloro-3,4-dimethyl-5-phenyl-1,3,2-oxazaphospholidine 2-sulfide reveal that the yield of radiogenic electron-capture reactions in the solid state strongly depends on intermolecular interactions in the crystal. In the present case a high yield of P-Cl three-electron-bond phosphoranyl radical anions is found in crystals of the 2R,4S,5R isomer, whereas no radical formation can be detected for the 2S,4S,5R isomer. An analysis of nonbonded interactions with neighboring molecules reveals that the geometry relaxation necessary for the radical stabilization is easily accommodated in crystals of the 2R,4S,SR isomer but not in the 2S,4S,5R isomer, explaining the observed difference in electron-capture efficiency. Experiments on radical formation in a MeTHF host matrix give further insight into the importance of the environment on radiogenic radical formation. The possible concurrent effect of the matrix on the electronic configuration and spin density distribution of the resulting phosphoranyl radical is discussed

  9. Electron-phonon relaxation and excited electron distribution in gallium nitride

    Energy Technology Data Exchange (ETDEWEB)

    Zhukov, V. P. [Institute of Solid State Chemistry, Urals Branch of the Russian Academy of Sciences, Pervomayskaya st. 91, Yekaterinburg (Russian Federation); Donostia International Physics Center (DIPC), P. Manuel de Lardizabal 4, 20018 San Sebastian (Spain); Tyuterev, V. G., E-mail: valtyut00@mail.ru [Donostia International Physics Center (DIPC), P. Manuel de Lardizabal 4, 20018 San Sebastian (Spain); Tomsk State Pedagogical University, Kievskaya st. 60, Tomsk (Russian Federation); Tomsk State University, Lenin st. 36, Tomsk (Russian Federation); Chulkov, E. V. [Donostia International Physics Center (DIPC), P. Manuel de Lardizabal 4, 20018 San Sebastian (Spain); Tomsk State University, Lenin st. 36, Tomsk (Russian Federation); Departamento de Fisica de Materiales, Facultad de Ciencias Qumicas, UPV/EHU and Centro de Fisica de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, Apdo. 1072, 20080 San Sebastian (Spain); Echenique, P. M. [Donostia International Physics Center (DIPC), P. Manuel de Lardizabal 4, 20018 San Sebastian (Spain); Departamento de Fisica de Materiales, Facultad de Ciencias Qumicas, UPV/EHU and Centro de Fisica de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, Apdo. 1072, 20080 San Sebastian (Spain)

    2016-08-28

    We develop a theory of energy relaxation in semiconductors and insulators highly excited by the long-acting external irradiation. We derive the equation for the non-equilibrium distribution function of excited electrons. The solution for this function breaks up into the sum of two contributions. The low-energy contribution is concentrated in a narrow range near the bottom of the conduction band. It has the typical form of a Fermi distribution with an effective temperature and chemical potential. The effective temperature and chemical potential in this low-energy term are determined by the intensity of carriers' generation, the speed of electron-phonon relaxation, rates of inter-band recombination, and electron capture on the defects. In addition, there is a substantial high-energy correction. This high-energy “tail” largely covers the conduction band. The shape of the high-energy “tail” strongly depends on the rate of electron-phonon relaxation but does not depend on the rates of recombination and trapping. We apply the theory to the calculation of a non-equilibrium distribution of electrons in an irradiated GaN. Probabilities of optical excitations from the valence to conduction band and electron-phonon coupling probabilities in GaN were calculated by the density functional perturbation theory. Our calculation of both parts of distribution function in gallium nitride shows that when the speed of the electron-phonon scattering is comparable with the rate of recombination and trapping then the contribution of the non-Fermi “tail” is comparable with that of the low-energy Fermi-like component. So the high-energy contribution can essentially affect the charge transport in the irradiated and highly doped semiconductors.

  10. Metadata capture in an electronic notebook: How to make it as simple as possible?

    Directory of Open Access Journals (Sweden)

    Menzel, Julia

    2015-09-01

    Full Text Available In the last few years electronic laboratory notebooks (ELNs have become popular. ELNs offer the great possibility to capture metadata automatically. Due to the high documentation effort metadata documentation is neglected in science. To close the gap between good data documentation and high documentation effort for the scientists a first user-friendly solution to capture metadata in an easy way was developed.At first, different protocols for the Western Blot were collected within the Collaborative Research Center 1002 and analyzed. Together with existing metadata standards identified in a literature search a first version of the metadata scheme was developed. Secondly, the metadata scheme was customized for future users including the implementation of default values for automated metadata documentation.Twelve protocols for the Western Blot were used to construct one standard protocol with ten different experimental steps. Three already existing metadata standards were used as models to construct the first version of the metadata scheme consisting of 133 data fields in ten experimental steps. Through a revision with future users the final metadata scheme was shortened to 90 items in three experimental steps. Using individualized default values 51.1% of the metadata can be captured with present values in the ELN.This lowers the data documentation effort. At the same time, researcher could benefit by providing standardized metadata for data sharing and re-use.

  11. Electron-electron interaction and transfer ionization in fast ion-atom collisions

    International Nuclear Information System (INIS)

    Voitkiv, A B

    2008-01-01

    Recently it was pointed out that electron capture occurring in fast ion-atom collisions can proceed via a mechanism which earlier was not considered. In the present paper we study this mechanism in more detail. Similarly as in radiative capture, where the electron transfer occurs due to the interaction with the radiation field and proceeds via emission of a photon, within this mechanism the electron capture is caused by the interaction with another atomic electron leading mainly to the emission of the latter. In contrast to the electron-electron Thomas capture, this electron-electron (E-E) mechanism is basically a first-order one having similarities to the kinematic and radiative capture channels. It also possesses important differences with the latter two. Leading to transfer ionization, this first-order capture mechanism results in the electron emission mainly in the direction opposite to the motion of the projectile ion. The same, although less pronounced, feature is also characteristic for the momenta of the target recoil ions produced via this mechanism. It is also shown that the action of the E-E mechanism is clearly seen in recent experimental data on the transfer ionization in fast proton-helium collisions.

  12. Analysis of neonicotinoids by gas chromatography coupled to nuclide {sup 63}Ni - Electron Capture Detector - GC/ECD

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Priscila O.; Leao, Claudio; Redigolo, Marcelo M.; Crepaldi, Caike; Bustillos, Oscar V., E-mail: priscilaoamaral@gmail.com, E-mail: claudio.leao@usp.br, E-mail: marceloredigolo@gmail.com, E-mail: caike1995@gmail.com, E-mail: ovega@ipen.bremails [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Recently, several reports have been published discussing reduction in bee population which polymerizes cultures around the world this phenomenon is known as Colony Collapse Disorder (CCD). The phenomenon describes the lack of worker honeybees in the colony despite having pups and food. The causes of this problem are unknown but there are studies that claim that reduction of population of bees is linked to poisoning through insecticides specifically neonicotinoids. Among this type of pesticide are imidacloprid (C{sub 9}H{sub 10}ClN{sub 5}O{sub 2}), clothianidin (C{sub 6}H{sub 8}ClN{sub 5}O{sub 2}S) and thiamethoxam (C{sub 8}H{sub 10}ClN{sub 5}O{sub 3}S). This paper presents the analysis of neonicotinoids - clothianidin, imidacloprid and thiamethoxam - by the technique of gas chromatography coupled to nuclide {sup 63}Ni electron capture detector (GC/ECD). The electron capture detector (ECD) is a gas chromatography detector that has been used for the detection of organic halogens, nitriles, nitrates and organometallic compounds. The ECD detector ionizes the analytes by the beta particles from the nuclide sources {sup 63}Ni within carrier gas N{sub 2}. The electrons produced in this process are collected and create a current that are amplified and generates a chromatographic peak. Methodology and details of the analysis are present in this work. (author)

  13. Low energy electron capture in collisions of C3+ with He

    International Nuclear Information System (INIS)

    Wu, Y.; Qi, Y.Y.; Yan, J.; Wang, J.G.; Li, Y.; Buenker, R.J.; Kato, D.

    2009-06-01

    Charge transfer processes due to collisions of ground state C 3+ (1s 2 2s 2 S) ions with He atom are investigated using the quantum-mechanical molecular-orbital close-coupling (QMOCC) method for energies between 10 -4 eV/u and 10 3 eV/u. The ab initio adiabatic potential and radial coupling utilized in the QMOCC calculations are obtained from the multi-reference single- and double-excitation configuration interaction (MRD-CI) approach. Total and state-selective single electron capture (SEC) cross sections and rate coefficients are obtained and compared with the available experimental and theoretical data. Good agreement between the measured SEC cross sections and the present calculation is found, but the previous calculation of total rate coefficient using the Landau-Zener model is one or two orders of magnitude smaller than the present result. (author)

  14. Nonlinear electrostatic emittance compensation in kA, fs electron bunches

    International Nuclear Information System (INIS)

    Geer, S.B. van der; Loos, M.J. de; Botman, J.I.M.; Luiten, O.J.; Wiel, M.J. van der

    2002-01-01

    Nonlinear space-charge effects play an important role in emittance growth in the production of kA electron bunches with a bunch length much smaller than the bunch diameter. We propose a scheme employing the radial third-order component of an electrostatic acceleration field, to fully compensate the nonlinear space-charge effects. This results in minimal transverse root-mean-square emittance. The principle is demonstrated using our design simulations of a device for the production of high-quality, high-current, subpicosecond electron bunches using electrostatic acceleration in a 1 GV/m field. Simulations using the GPT code produce a bunch of 100 pC and 73 fs full width at half maximum pulse width, resulting in a peak current of about 1.2 kA at an energy of 2 MeV. The compensation scheme reduces the root-mean-square emittance by 34% to 0.4π mm mrad

  15. Capturing Chemistry in Action with Electrons: Realization of Atomically Resolved Reaction Dynamics.

    Science.gov (United States)

    Ischenko, Anatoly A; Weber, Peter M; Miller, R J Dwayne

    2017-08-23

    One of the grand challenges in chemistry has been to directly observe atomic motions during chemical processes. The depiction of the nuclear configurations in space-time to understand barrier crossing events has served as a unifying intellectual theme connecting the different disciplines of chemistry. This challenge has been cast as an imaging problem in which the technical issues reduce to achieving not only sufficient simultaneous space-time resolution but also brightness for sufficient image contrast to capture the atomic motions. This objective has been met with electrons as the imaging source. The review chronicles the first use of electron structural probes to study reactive intermediates, to the development of high bunch charge electron pulses with sufficient combined spatial-temporal resolution and intensity to literally light up atomic motions, as well as the means to characterize the electron pulses in terms of temporal brightness and image reconstruction. The use of femtosecond Rydberg spectroscopy as a novel means to use internal electron scattering within the molecular reference frame to obtain similar information on reaction dynamics is also discussed. The focus is on atomically resolved chemical reaction dynamics with pertinent references to work in other areas and forms of spectroscopy that provide additional information. Effectively, we can now directly observe the far-from-equilibrium atomic motions involved in barrier crossing and categorize chemistry in terms of a power spectrum of a few dominant reaction modes. It is this reduction in dimensionality that makes chemical reaction mechanisms transferrable to seemingly arbitrarily complex (large N) systems, up to molecules as large as biological macromolecules (N > 1000 atoms). We now have a new way to reformulate reaction mechanisms using an experimentally determined dynamic mode basis that in combination with recent theoretical advances has the potential to lead to a new conceptual basis for

  16. Electronic capture of patient-reported and clinician-reported outcome measures in an elective orthopaedic setting: a retrospective cohort analysis.

    Science.gov (United States)

    Malhotra, Karan; Buraimoh, Olatunbosun; Thornton, James; Cullen, Nicholas; Singh, Dishan; Goldberg, Andrew J

    2016-06-20

    To determine whether an entirely electronic system can be used to capture both patient-reported outcomes (electronic Patient-Reported Outcome Measures, ePROMs) as well as clinician-validated diagnostic and complexity data in an elective surgical orthopaedic outpatient setting. To examine patients' experience of this system and factors impacting their experience. Retrospective analysis of prospectively collected data. Single centre series. Outpatient clinics at an elective foot and ankle unit in the UK. All new adult patients attending elective orthopaedic outpatient clinics over a 32-month period. All patients were invited to complete ePROMs prior to attending their outpatient appointment. At their appointment, those patients who had not completed ePROMs were offered the opportunity to complete it on a tablet device with technical support. Matched diagnostic and complexity data were captured by the treating consultant during the appointment. Capture rates of patient-reported and clinician-reported data. All information and technology (IT) failures, language and disability barriers were captured. Patients were asked to rate their experience of using ePROMs. The scoring systems used included EQ-5D-5L, the Manchester-Oxford Foot Questionnaire (MOxFQ) and the Visual Analogue Scale (VAS) pain score. Out of 2534 new patients, 2176 (85.9%) completed ePROMs, of whom 1090 (50.09%) completed ePROMs at home/work prior to their appointment. 31.5% used a mobile (smartphone/tablet) device. Clinician-reported data were captured on 2491 patients (98.3%). The mean patient experience score of using Patient-Reported Outcome Measures (PROMs) was 8.55±1.85 out of 10 and 666 patients (30.61%) left comments. Of patients leaving comments, 214 (32.13%) felt ePROMs did not adequately capture their symptoms and these patients had significantly lower patient experience scores (ptechnology into a service improvement programme. Excellent capture rates of ePROMs and clinician

  17. Capture into resonance and phase-space dynamics in an optical centrifuge

    Science.gov (United States)

    Armon, Tsafrir; Friedland, Lazar

    2016-04-01

    The process of capture of a molecular ensemble into rotational resonance in the optical centrifuge is investigated. The adiabaticity and phase-space incompressibility are used to find the resonant capture probability in terms of two dimensionless parameters P1 ,2 characterizing the driving strength and the nonlinearity, and related to three characteristic time scales in the problem. The analysis is based on the transformation to action-angle variables and the single resonance approximation, yielding reduction of the three-dimensional rotation problem to one degree of freedom. The analytic results for capture probability are in good agreement with simulations. The existing experiments satisfy the validity conditions of the theory.

  18. The coulometric electron capture detector and its application to the selected freons in water and air. Part of a coordinated programme on the analysis of organic compounds by electron capture gas chromatography

    International Nuclear Information System (INIS)

    Lasa, J.

    1981-01-01

    In developing the use of Freon-11 and Freon-12 as environmental tracers in aeronomy, oceanography and hydrology electron capture gas chromatography was used to measure the concentration changes. A detector in the coulometric mode was designed and operated as a solute switch. The detection limit was in the order of 0.2x10 -12 g for a modified head space method in handling aqueous samples. Theoretical analysis of the detector design and the effects of factors including pulsing period, flowrates of carrier gas and the radioactivity of the detector source were discussed and confirmed experimentally

  19. Compton scattering of 145 keV gamma rays by K-shell electrons of silver

    Energy Technology Data Exchange (ETDEWEB)

    Acharya, V B; Singh, B; Ghumman, B S [Punjabi Univ., Patiala (India). Dept. of Physics

    1981-01-01

    Differential cross-sections for the incoherent scattering of 145 keV photons from K-shell electrons of silver are measured at scattering angles ranging from 30/sup 0/ to 150/sup 0/ to investigate the effect of electron binding on the scattering process in the low energy region. Measurements are made employing two NaI (Tl) scintillation spectrometers and a slow-fast coincidence circuit of resolving time 30 ns. The experimental results are compared with the available theoretical data. The total K-shell scattering cross-section is also estimated and is about 45% of the free electron cross-section.

  20. JAERI 200 kV electron gun with an NEA-GaAs photocathode

    International Nuclear Information System (INIS)

    Nishitani, Tomohiro; Minehara, Eisuke J.; Hajima, Ryoichi; Nagai, Ryoji; Sawamura, Masaru; Nishimori, Nobuyuki; Kikuzawa, Nobuhiro; Yamauchi, Toshihiko

    2004-01-01

    The photocathode DC-gun with high average current, low beam emittance and long operational lifetime is considered to be indispensable for ERL-FEL. We have started the development program of a 200 keV electron gun with the NEA-GaAs photocathode for the first time in JAERI. In order to long an NEA surface lifetime, the JAERI 200 kV electron gun system consists of a 200 kV DC-gun chamber on extreme high vacuum condition and an NEA activation chamber with load-lock system. We report the goal of photocathode DC-gun R and D and the schedule of a developmental program. (author)

  1. Radioprotective effects of dimethyl sulfoxide in golden hamster embryo cells exposed to gamma rays at 77 K. I. Radical formation as studied by electron spin resonance

    International Nuclear Information System (INIS)

    Miyazaki, T.; Hayakawa, Y.; Suzuki, K.; Suzuki, M.; Watanabe, M.

    1990-01-01

    Formation of free radicals in golden hamster embryo (GHE) cells in the frozen living state by gamma irradiation has been studied by electron spin resonance spectroscopy at 4.2 and 77 K. The relative yields of H atoms, OH radicals, and organic radicals trapped in the irradiated GHE cells are 12, 72, and 16%, respectively, of total radical yields. When dimethylsulfoxide (DMSO) is added to GHE cells at 77 K, a large quantity of CH2SOCH3 radicals (DMSO radicals) are formed after gamma irradiation. The yields of OH radicals are not affected by the addition of DMSO. When the GHE cell-DMSO mixtures are irradiated with gamma rays at 77 K and then warmed to 111 K, the OH radicals decay, whereas the DMSO radicals do not increase complementarily. Moreover, the decay rates of the OH radicals at 111 K do not depend upon the concentration of DMSO. Thus OH radicals do not react with DMSO during warming of the irradiated sample. When H atoms are produced by gamma irradiation of acid ice at 60 K, the decay rates of the H atoms at 77 K increase with increasing DMSO concentration, indicating that DMSO reacts with H atoms (CH3SOCH3 + H----.CH2SOCH3 + H2) at 77 K by quantum-mechanical tunneling. When the GHE cell-DMSO mixture is irradiated with gamma rays at 77 or 4.2 K in the dark, DMSO ions are produced in addition to DMSO radicals. Therefore it is concluded that DMSO does not scavenge OH radicals, but does capture H atoms, holes and/or electrons in the gamma-irradiated cells, resulting in the remarkable formation of DMSO radicals. This scavenger effect of DMSO may be related to the radioprotection of DMSO against cell killing

  2. Evolution of the spectrum of the solvated electron in BeF2 aqueous glasses at 76 K

    International Nuclear Information System (INIS)

    Nguyen, T.Q.; Walker, D.C.; Gillis, H.A.

    1978-01-01

    Evidence is presented for a spontaneous shift from infrared-to- red-to-green in the overall spectrum of the electron trapped in an aqueous glass at 76 K following nanosecond pulse radiolysis. As with the alcohols, after the pulse the infrared absorption decays, there is a growth-then-decay of absorbance at intermediate wavelengths and net growth of absorption due to the equilibrated trapped electron state, e - /sub vis/. This progressive transition was not characterised by a single-step process and was discernible in aqueous glasses containing 7.5 or 10.7M BeF 2 in D 2 O. At higher BeF 2 concentrations, or with LiBr as glass-forming electrolyte, no growth of e - /sub vis/ was observed, probably because of concurrent loss of e - /sub vis/ in those glasses, as in LiCl and other glasses. BeF 2 glasses of trapped electrons showed several other features of interest: (i) wavelength- selective bleaching of the e - /sub vis/ band indicates that it is composed of a broad ''green'' band (lambda/sub max/, 530--590 nm) which bleaches homogeneously, and a broad ''red'' region which bleaches inhomogeneously. (ii) lambda/sub max/ for e - /sub vis/ changes with BeF 2 concentration, being blue shifted with increasing concentration , with both green and red underlying structures shifting slightly. (iii) No absorption due to F - 2 was found following pulse radiolysis in these glasses at 76 K. (iv) Several recent findings with LiCl are mimicked by F - 2 glasses. For instance, G (e - /sub vis/) increases and G (e - /sub ir/) decreases as the electrolyte concentration is increased, while the combined yield remains constant at 1.8 +- 0.1

  3. Capture into resonance and phase space dynamics in optical centrifuge

    Science.gov (United States)

    Armon, Tsafrir; Friedland, Lazar

    2016-05-01

    The process of capture of a molecular enesemble into rotational resonance in the optical centrifuge is investigated. The adiabaticity and phase space incompressibility are used to find the resonant capture probability in terms of two dimensionless parameters P1 , 2 characterising the driving strength and the nonlinearity, and related to three characteristic time scales in the problem. The analysis is based on the transformation to action-angle variables and the single resonance approximation, yielding reduction of the three-dimensional rotation problem to one degree of freedom. The analytic results for capture probability are in a good agreement with simulations. The existing experiments satisfy the validity conditions of the theory. This work was supported by the Israel Science Foundation Grant 30/14.

  4. Electron capture in very low energy collisions of multicharged ions with H and D in merged beams

    International Nuclear Information System (INIS)

    Havener, C.C.; Meyer, F.W.; Phaneuf, R.A.

    1991-01-01

    An ion-atom merged-beams technique is being used to measure total absolute electron-capture cross sections for multicharged ions in collisions with H (or D) in the energy range between 0.1 and 1000 eV/amu. Comparison between experiment and theory over such a large energy range constitutes a critical test for both experiment and theory. Total capture cross-section measurements for O 3+ H(D) and O 5+ + H(D) are presented and compared to state selective and differential cross section calculations. Landau-Zener calculations show that for O 5+ the sharp increase in the measured cross section below 1 eV/amu is partly due to trajectory effects arising from the ion-induced dipole interaction between the reactants. 20 refs., 8 figs

  5. Double capture in the O8+ + He collision investigated by electron spectroscopy (80 keV, 10 deg)

    International Nuclear Information System (INIS)

    Moretto-Capelle, P.; Benoit-Cattin, P.; Bordenave-Montesquieu, A.; Boudjema, M.; Gleizes, A.; Dousson, S.; Hitz, D.

    1989-01-01

    Double capture into (3,n) autoionising states of O 6+ is observed in the O 8+ + He collision system by electron spectroscopy at 80 keV, 10 0 . A comparison of the experimental results with theoretical positions and lifetimes allows the (3,3) states as well as three groups of (3,4) states to be identified. The present experimental findings are compared with earlier data for the N 7+ + He and Ne 8+ (1s 2 ) + He systems. The influence of the core of the multicharged ion is studied by examining the O 8+ and Ne 8+ (1s 2 ) results. The total double capture cross section is found to be large and it is compared with available experimental and theoretical data. (author)

  6. CO2 Capture by Absorption with Potassium Carbonate

    Energy Technology Data Exchange (ETDEWEB)

    Gary T. Rochelle; Eric Chen; Babatunde Oyenekan; Andrew Sexton; Jason Davis; Marcus Hilliard; Amorvadee Veawab

    2006-07-28

    The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. The pilot plant data have been reconciled using 17% inlet CO{sub 2}. A rate-based model demonstrates that the stripper is primarily controlled by liquid film mast transfer resistance, with kinetics at vacuum and diffusion of reactants and products at normal pressure. An additional major unknown ion, probably glyoxylate, has been observed in MEA degradation. Precipitation of gypsum may be a feasible approach to removing sulphate from amine solutions and providing for simultaneous removal of CO{sub 2} and SO{sub 2}. Corrosion of carbon steel in uninhibited MEA solution is increased by increased amine concentration, by addition of piperazine, and by greater CO{sub 2} loading.

  7. Capture and transfer of stopped pions in alcohols

    International Nuclear Information System (INIS)

    Harston, M.R.; Armstrong, D.S.; Measday, D.F.; Stanislaus, S.; Weber, P.; Horvath, D.

    1990-02-01

    The pion charge exchange probability in hydrogen for stopped π - has been measured for a series of alcohols. The relative atomic capture probabilities for hydrogen in different chemical environments as well as for the other molecular constituents were extracted from the data using a phenomenological approach. The results allow the prediction of the charge exchange probability in other molecules of similar chemical structure. The charge exchange probability in deuterated methanols was measured and compared to the prediction of our model. A comprehensive picture is obtained if pion transfer from hydrogen to deuterium is included

  8. Diffraction and absorption of inelastically scattered electrons for K-shell ionization

    International Nuclear Information System (INIS)

    Josefsson, T.W.; Allen, L.J.

    1995-01-01

    An expression for the nonlocal inelastic scattering cross section for fast electrons in a crystalline environment, which explicitly includes diffraction as well as absorption for the inelastically scattered electrons, is used to carry out realistic calculations of K-shell electron energy loss spectroscopy (EELS) and energy dispersive x-ray (EDX) analysis cross sections. The calculations demonstrate quantitatively why, in EDX spectroscopy, integration over the dynamical states of the inelastically scattered electron averages in such a way that an effective plane wave representation of the scattered electrons is a good approximation. This is only the case for large enough acceptance angles of the detector in an EELS experiment. For EELS with smaller detector apertures, explicit integration over the dynamical final states is necessary and inclusion of absorption for the scattered electrons is important, particularly for thicker crystals. 50 refs., 7 figs

  9. On the universality of knot probability ratios

    Energy Technology Data Exchange (ETDEWEB)

    Janse van Rensburg, E J [Department of Mathematics and Statistics, York University, Toronto, Ontario M3J 1P3 (Canada); Rechnitzer, A, E-mail: rensburg@yorku.ca, E-mail: andrewr@math.ubc.ca [Department of Mathematics, University of British Columbia, 1984 Mathematics Road, Vancouver, BC V6T 1Z2 (Canada)

    2011-04-22

    Let p{sub n} denote the number of self-avoiding polygons of length n on a regular three-dimensional lattice, and let p{sub n}(K) be the number which have knot type K. The probability that a random polygon of length n has knot type K is p{sub n}(K)/p{sub n} and is known to decay exponentially with length (Sumners and Whittington 1988 J. Phys. A: Math. Gen. 21 1689-94, Pippenger 1989 Discrete Appl. Math. 25 273-8). Little is known rigorously about the asymptotics of p{sub n}(K), but there is substantial numerical evidence. It is believed that the entropic exponent, {alpha}, is universal, while the exponential growth rate is independent of the knot type but varies with the lattice. The amplitude, C{sub K}, depends on both the lattice and the knot type. The above asymptotic form implies that the relative probability of a random polygon of length n having prime knot type K over prime knot type L. In the thermodynamic limit this probability ratio becomes an amplitude ratio; it should be universal and depend only on the knot types K and L. In this communication we examine the universality of these probability ratios for polygons in the simple cubic, face-centred cubic and body-centred cubic lattices. Our results support the hypothesis that these are universal quantities. For example, we estimate that a long random polygon is approximately 28 times more likely to be a trefoil than be a figure-eight, independent of the underlying lattice, giving an estimate of the intrinsic entropy associated with knot types in closed curves. (fast track communication)

  10. Measurement of Plutonium-240 Angular Momentum Dependent Fission Probabilities Using the Alpha-Alpha' Reaction

    Science.gov (United States)

    Koglin, Johnathon

    Accurate nuclear reaction data from a few keV to tens of MeV and across the table of nuclides is essential to a number of applications of nuclear physics, including national security, nuclear forensics, nuclear astrophysics, and nuclear energy. Precise determination of (n, f) and neutron capture cross sections for reactions in high- ux environments are particularly important for a proper understanding of nuclear reactor performance and stellar nucleosynthesis. In these extreme environments reactions on short-lived and otherwise difficult-to-produce isotopes play a significant role in system evolution and provide insights into the types of nuclear processes taking place; a detailed understanding of these processes is necessary to properly determine cross sections far from stability. Indirect methods are often attempted to measure cross sections on isotopes that are difficult to separate in a laboratory setting. Using the surrogate approach, the same compound nucleus from the reaction of interest is created through a "surrogate" reaction on a different isotope and the resulting decay is measured. This result is combined with appropriate reaction theory for compound nucleus population, from which the desired cross sections can be inferred. This method has shown promise, but the theoretical framework often lacks necessary experimental data to constrain models. In this work, dual arrays of silicon telescope particle identification detectors and photovoltaic (solar) cell fission fragment detectors have been used to measure the fission probability of the 240Pu(alpha, alpha'f) reaction - a surrogate for the 239Pu(n, f) - and fission of 35.9(2)MeV at eleven scattering angles from 40° to 140° in 10° intervals and at nuclear excitation energies up to 16MeV. Within experimental uncertainty, the maximum fission probability was observed at the neutron separation energy for each alpha scattering angle. Fission probabilities were separated into five 500 keV bins from 5:5MeV to

  11. The development of a 200 kV monochromated field emission electron source

    Energy Technology Data Exchange (ETDEWEB)

    Mukai, Masaki, E-mail: mmukai@jeol.co.jp [JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558 (Japan); Kim, Judy S. [University of Oxford, Department of Materials, Parks Road, Oxford, OX1 3PH (United Kingdom); Omoto, Kazuya; Sawada, Hidetaka; Kimura, Atsushi; Ikeda, Akihiro; Zhou, Jun; Kaneyama, Toshikatsu [JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558 (Japan); Young, Neil P.; Warner, Jamie H.; Nellist, Peter D.; Kirkland, Angus I. [University of Oxford, Department of Materials, Parks Road, Oxford, OX1 3PH (United Kingdom)

    2014-05-01

    We report the development of a monochromator for an intermediate-voltage aberration-corrected electron microscope suitable for operation in both STEM and TEM imaging modes. The monochromator consists of two Wien filters with a variable energy selecting slit located between them and is located prior to the accelerator. The second filter cancels the energy dispersion produced by the first filter and after energy selection forms a round monochromated, achromatic probe at the specimen plane. The ultimate achievable energy resolution has been measured as 36 meV at 200 kV and 26 meV at 80 kV. High-resolution Annular Dark Field STEM images recorded using a monochromated probe resolve Si–Si spacings of 135.8 pm using energy spreads of 218 meV at 200 kV and 217 meV at 80 kV respectively. In TEM mode an improvement in non-linear spatial resolution to 64 pm due to the reduction in the effects of partial temporal coherence has been demonstrated using broad beam illumination with an energy spread of 134 meV at 200 kV. - Highlights: • Monochromator for 200 kV aberration corrected TEM and STEM was developed. • Monochromator produces monochromated and achromatic probe at specimen plane. • Ultimate energy resolution was measured to be 36 meV at 200 kV and 26 meV at 80 kV. • Atomic resolution STEM images were recorded using monochromated electron probe. • Improvements of TEM resolution were confirmed using monochromated illumination.

  12. The development of a 200 kV monochromated field emission electron source

    International Nuclear Information System (INIS)

    Mukai, Masaki; Kim, Judy S.; Omoto, Kazuya; Sawada, Hidetaka; Kimura, Atsushi; Ikeda, Akihiro; Zhou, Jun; Kaneyama, Toshikatsu; Young, Neil P.; Warner, Jamie H.; Nellist, Peter D.; Kirkland, Angus I.

    2014-01-01

    We report the development of a monochromator for an intermediate-voltage aberration-corrected electron microscope suitable for operation in both STEM and TEM imaging modes. The monochromator consists of two Wien filters with a variable energy selecting slit located between them and is located prior to the accelerator. The second filter cancels the energy dispersion produced by the first filter and after energy selection forms a round monochromated, achromatic probe at the specimen plane. The ultimate achievable energy resolution has been measured as 36 meV at 200 kV and 26 meV at 80 kV. High-resolution Annular Dark Field STEM images recorded using a monochromated probe resolve Si–Si spacings of 135.8 pm using energy spreads of 218 meV at 200 kV and 217 meV at 80 kV respectively. In TEM mode an improvement in non-linear spatial resolution to 64 pm due to the reduction in the effects of partial temporal coherence has been demonstrated using broad beam illumination with an energy spread of 134 meV at 200 kV. - Highlights: • Monochromator for 200 kV aberration corrected TEM and STEM was developed. • Monochromator produces monochromated and achromatic probe at specimen plane. • Ultimate energy resolution was measured to be 36 meV at 200 kV and 26 meV at 80 kV. • Atomic resolution STEM images were recorded using monochromated electron probe. • Improvements of TEM resolution were confirmed using monochromated illumination

  13. The 50 kV inverted source of polarized electrons at ELSA

    International Nuclear Information System (INIS)

    Hillert, Wolfgang; Gowin, Michael; Neff, Berhold

    2001-01-01

    The future medium energy physics program at the electron stretcher accelerator ELSA of Bonn University mainly relies on experiments requiring a beam of polarized electrons and a polarized target. To provide a polarized beam with high polarization and sufficient intensity a pulsed 50 kV inverted gun of polarized electrons has been set into operation. The gun is operated in space charge limitation, producing a peak current of 100 mA in rectangular 1μs long electron pulses. Photocathode lifetime during operation is higher than 3000 hours. Using a Be-InGaAs/Be-AlGaAs superlattice photocathode a polarization of 80% and a corresponding quantum efficiency of 0.4% could be obtained

  14. Predicting non-square 2D dice probabilities

    Science.gov (United States)

    Pender, G. A. T.; Uhrin, M.

    2014-07-01

    The prediction of the final state probabilities of a general cuboid randomly thrown onto a surface is a problem that naturally arises in the minds of men and women familiar with regular cubic dice and the basic concepts of probability. Indeed, it was considered by Newton in 1664 (Newton 1967 The Mathematical Papers of Issac Newton vol I (Cambridge: Cambridge University Press) pp 60-1). In this paper we make progress on the 2D problem (which can be realized in 3D by considering a long cuboid, or alternatively a rectangular cross-sectioned dreidel). For the two-dimensional case we suggest that the ratio of the probabilities of landing on each of the two sides is given by \\frac{\\sqrt{{{k}^{2}}+{{l}^{2}}}-k}{\\sqrt{{{k}^{2}}+{{l}^{2}}}-l}\\frac{arctan \\frac{l}{k}}{arctan \\frac{k}{l}} where k and l are the lengths of the two sides. We test this theory both experimentally and computationally, and find good agreement between our theory, experimental and computational results. Our theory is known, from its derivation, to be an approximation for particularly bouncy or ‘grippy’ surfaces where the die rolls through many revolutions before settling. On real surfaces we would expect (and we observe) that the true probability ratio for a 2D die is a somewhat closer to unity than predicted by our theory. This problem may also have wider relevance in the testing of physics engines.

  15. Distribution characteristics of energetic electron according to data of Interkosmos-17 satellite

    International Nuclear Information System (INIS)

    Martynov, A.I.; Makhmutov, V.S.; Petrov, V.M.; Shurshakov, V.A.

    1990-01-01

    Distributions of quasi-captured and precipitating electrons with E=10-70 keV within L=3-15 by local time and local pitch-angle for different conditions of magnetic perturbation are studied using measurement data from Interkosmos-17 satellite (polar circular orbit, h∼500 km). Dependence of electron flows on local time obtained for K p >1 is close to corresponding dependence from AE-4 model, and level of magnetosphere perturbation affects character of this dependence. Electron distributions by invariant latitude in the Earth polar cap are calculated at different levels of geomagnetic perturbation; electron flows during strong magnetic perturbations (K p >4) increase by ∼2 times, in this case, space heterogeneity of their distribution is intensified

  16. Notification determining technical standards concerning prevention of radiation injuries by electron capture detectors for gas chromatography

    International Nuclear Information System (INIS)

    1981-01-01

    This rule is established under the provisions of the law on the prevention of radiation injuries by radioisotopes, the ordinance and the regulation for the execution of the law. This rule is applied to electron capture detectors for gas chromatography under the law. Basic terms are defined, such as detector radiation source, detector container and carrier gas. The detectors shall consist of detector radiation sources and containers, and the containers must be such that the radiation sources can not be easily taken away and never cause the danger to fall off. The induction and discharge mouths of the detector containers shall be shut tightly with caps, etc. The main structures and radiation sources of detectors shall be made of materials, which are difficult to corrode, and do not melt and easily cause chemical change below 800 deg. C. Detector radiation sources shall be made of metals plated with nickel 63 less than 20 milli-curie. The radiation dose rate on the surface of a detector shall be shielded to less than 0.06 milli-rem an hour. The temperature of detectors and carrier gas shall not exceed 350 deg. C. Corrosive gas shall not be used as carrier gas. The period of effective indication is 5 years. The method of washing, and the conditions of leak, heat-resistance and shock-resistance examinations are defined, respectively. (Okada, K.)

  17. Electron capture in collisions of S{sup 4+} with atomic hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Stancil, P.C. [Department of Physics and Astronomy, University of Georgia, Athens, GA (United States)]. E-mail: stancil@physast.uga.edu; Turner, A.R. [Department of Chemistry, University of Liverpool, Liverpool (United Kingdom)]. E-mail: art@liv.ac.uk; Cooper, D.L. [Department of Chemistry, University of Liverpool, Liverpool (United Kingdom)]. E-mail: dlc@liv.ac.uk; Schultz, D.R. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)]. E-mail: schultz@mail.phy.ornl.gov; Rakovic, M.J. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)]. E-mail: milun@mail.phy.ornl.gov; Fritsch, W. [Abteilung Theoretische Physik, Hahn-Meitner-Institut Berlin, Berlin (Germany)]. E-mail: fritsch@hmi.de; Zygelman, B. [Department of Physics, University of Nevada, Las Vegas, NV (United States)]. E-mail: bernard@physics.unlv.edu

    2001-06-28

    Charge transfer processes due to collisions of ground state S{sup 4+}(3s{sup 2} {sup 1}S) ions with atomic hydrogen are investigated for energies between 1 meV u{sup -1} and 10 MeV u{sup -1} using the quantum mechanical molecular-orbital close-coupling (MOCC), atomic-orbital close-coupling, classical trajectory Monte Carlo (CTMC) and continuum distorted wave methods. The MOCC calculations utilize ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained with the spin-coupled valence-bond approach. A number of variants of the CTMC approach were explored, including different momentum and radial distributions for the initial state, as well as effective charge and quantum-defect models to determine the corresponding quantum state after capture into final partially stripped S{sup 3+} excited classical states. Hydrogen target isotope effects are explored and rate coefficients for temperatures between 100 and 10{sup 6} K are also presented. (author)

  18. Zero field reversal probability in thermally assisted magnetization reversal

    Science.gov (United States)

    Prasetya, E. B.; Utari; Purnama, B.

    2017-11-01

    This paper discussed about zero field reversal probability in thermally assisted magnetization reversal (TAMR). Appearance of reversal probability in zero field investigated through micromagnetic simulation by solving stochastic Landau-Lifshitz-Gibert (LLG). The perpendicularly anisotropy magnetic dot of 50×50×20 nm3 is considered as single cell magnetic storage of magnetic random acces memory (MRAM). Thermally assisted magnetization reversal was performed by cooling writing process from near/almost Curie point to room temperature on 20 times runs for different randomly magnetized state. The results show that the probability reversal under zero magnetic field decreased with the increase of the energy barrier. The zero-field probability switching of 55% attained for energy barrier of 60 k B T and the reversal probability become zero noted at energy barrier of 2348 k B T. The higest zero-field switching probability of 55% attained for energy barrier of 60 k B T which corespond to magnetif field of 150 Oe for switching.

  19. Atomic ionization at positron-electron annihilation at β+-decay

    International Nuclear Information System (INIS)

    Fedotkin, S.N.

    2012-01-01

    The role of the nuclear charge screening and corrections to the Born approximation for the flying from atom electron in a process of atomic ionization at annihilation of positron with another electron of daughter's atom at β + - decay is studied. It was considered the processes of ionization of different atomic shells (n = 1, 2, 3, 4) at annihilation of positron, emitted at β'+ - decay with K- electron of daughter's atom. It is shown that the screening effect is important only for shell with n = 4. While corrections to the Born approximation plays the essential role for all shells. It is shown that the most probable process is related with emission of the another K- electron

  20. Thermodynamic modeling of NH_3-CO_2-SO_2-K_2SO_4-H_2O system for combined CO_2 and SO_2 capture using aqueous NH_3

    International Nuclear Information System (INIS)

    Qi, Guojie; Wang, Shujuan

    2017-01-01

    Highlights: • A new application of aqueous NH_3 based combined CO_2 and SO_2 process was proposed. • A thermodynamic model simulated the heat of absorption and the K_2SO_4 precipitation. • The CO_2 content can be regenerated in a stripper with lower heat of desorption. • The SO_2 content can be removed by K_2SO_4 precipitation from the lean NH_3 solvent. - Abstract: A new application of aqueous NH_3 based post-combustion CO_2 and SO_2 combined capture process was proposed to simultaneously capture CO_2 and SO_2, and remove sulfite by solid (K_2SO_4) precipitation method. The thermodynamic model of the NH_3-CO_2-SO_2-K_2SO_4-H_2O system for the combined CO_2 and SO_2 capture process was developed and validated in this work to analyze the heat of CO_2 and SO_2 absorption in the NH_3-CO_2-SO_2-H_2O system, and the K_2SO_4 precipitation characteristics in the NH_3-CO_2-SO_2-K_2SO_4-H_2O system. The average heat of CO_2 absorption in the NH_3-CO_2-H_2O system at 40 °C is around −73 kJ/mol CO_2 in 2.5 wt% NH_3 with CO_2 loading between 0.2 and 0.5 C/N. The average heat of SO_2 absorption in the NH_3-SO_2-H_2O system at 40 °C is around −120 kJ/mol SO_2 in 2.5 wt% NH_3 with SO_2 loading between 0 and 0.5 S/N. The average heat of CO_2 absorption in the NH_3-CO_2-SO_2-H_2O system at 40 °C is 77, 68, and 58 kJ/mol CO_2 in 2.5 wt% NH_3 with CO_2 loading between 0.2 and 0.5 C/N, when SO_2 loading is 0, 0.1, 0.2 S/N, respectively. The solubility of K_2SO_4 increases with temperature, CO_2 and SO_2 loadings, but decreases with NH_3 concentration in the CO_2 and SO_2 loaded aqueous NH_3. The thermodynamic evaluation indicates that the combined CO_2 and SO_2 capture process could employ the typical absorption/regeneration process to simultaneously capture CO_2 and SO_2 in an absorber, thermally desorb CO_2 in a stripper, and feasibly remove sulfite (oxidized to sulfate) content by precipitating K_2SO_4 from the lean NH_3 solvent after the lean/rich heat exchanger.

  1. J-PARC Press Release: Electron neutrino oscillation detected at T2K

    CERN Multimedia

    T2K Press Office

    2011-01-01

    Tsukuba, Japan, June 15, 2011. The T2K experiment, whose primary purpose is to study neutrino interactions at a large distance from their source, has detected 6 electron neutrino candidate events based on the data collected before March 11, 2011. For the first time, it was possible to observe an indication that muon neutrinos are able to transform into electron neutrinos over a distance of 295 km through the quantum mechanical phenomena of neutrino flavor oscillations.   The Super-Kamiokande detector, in Japan. © 2011, High Energy Accelerator Research Organization, KEK. The T2K experiment is searching for the neutrino oscillation phenomena, where particular types of neutrinos transform into other types of neutrinos. These observations help determine neutrino masses, as well elucidating the uncharted nature of neutrinos, such as the relationship among three neutrino generations (types). T2K aims at the world’s best sensitivity by detecting neutrinos with the Super-Kamiokande d...

  2. Device of capturing for radioactive corrosion products

    International Nuclear Information System (INIS)

    Ohara, Atsushi; Fukushima, Kimichika.

    1984-01-01

    Purpose: To increase the area of contact between the capturing materials for the radioactive corrosion products contained in the coolants and the coolants by producing stirred turbulent flows in the coolant flow channel of LMFBR type reactors. Constitution: Constituent materials for the nuclear fuel elements or the reactor core structures are activated under the neutron irradiation, corroded and transferred into the coolants. While capturing devices made of pure metal nickel are used for the elimination of the corrosion products, since the coolants form laminar flows due to the viscosity thereof near the surface of the capturing materials, the probability that the corrosion products in the coolants flowing through the middle portion of the channel contact the capturing materials is reduced. In this invention, rotating rolls and flow channels in which the balls are rotated are disposed at the upstream of the capturing device to forcively disturb the flow of the liquid sodium, whereby the radioactive corrosion products can effectively be captured. (Kamimura, M.)

  3. Sufficient Statistics for Divergence and the Probability of Misclassification

    Science.gov (United States)

    Quirein, J.

    1972-01-01

    One particular aspect is considered of the feature selection problem which results from the transformation x=Bz, where B is a k by n matrix of rank k and k is or = to n. It is shown that in general, such a transformation results in a loss of information. In terms of the divergence, this is equivalent to the fact that the average divergence computed using the variable x is less than or equal to the average divergence computed using the variable z. A loss of information in terms of the probability of misclassification is shown to be equivalent to the fact that the probability of misclassification computed using variable x is greater than or equal to the probability of misclassification computed using variable z. First, the necessary facts relating k-dimensional and n-dimensional integrals are derived. Then the mentioned results about the divergence and probability of misclassification are derived. Finally it is shown that if no information is lost (in x = Bz) as measured by the divergence, then no information is lost as measured by the probability of misclassification.

  4. Electron paramagnetic resonance study of radicals formed by radiolysis at 77 K of nitroalkanes and of their solutions in organic glasses. Chromatography analysis of radiolysis products of nitromethane in ethanol solution in a vitreous medium

    International Nuclear Information System (INIS)

    Rosilio, C.

    1969-01-01

    With a view to explaining the formation of the final products resulting from the photolysis and the radiolysis of nitro-alkanes, we have attempted to identify the paramagnetic species formed as intermediates during the radiolysis. Our work has covered the structure and the reactivity of the radicals formed by 7 irradiation of the nitrogen containing derivatives at 77 K, and on the mechanism of formation and of disappearance of these radicals in the various matrices used. The radicals resulting from the removal of a hydrogen atom in the α position of the NO 2 group, and the radicals resulting from addition reactions on the nitrogen group characterized by an unpaired electron on the nitrogen have been identified, either during the radiolysis of pure nitroalkanes, or during the radiolysis of nitro-alkanes in solution in organic glasses at 77 K. A study has been made of the conformation and the movements of radicals in the matrices, and the mechanism of formation of the observed radicals produced generally by the capture by the nitro-alkanes of primary radiolysis species. The nitro-alkanes in ethanol solution can behave as traps both for electrons and for free radicals. The study of the radiolysis of nitro-alkanes in solution in a polar ethanol glass has been completed with chemical analyses on the final radiolysis products; it has been possible to deduce the capture efficiency of trapped electrons and of free radicals by nitro-alkanes in ethanol. For this we have determined the radio-chemical yields of hydrogen, acetaldehyde and glycol as a function of the capture agent concentration, for the nitro-methane-ethanol system. A mechanism for the disappearance of the observed radicals is proposed. (author) [fr

  5. The bimolecular reaction of radiolysis product of hydrated electron at temperature up to 473K; Reaksi bimolekular antar produk radiolisis elektron terhidrasi pada temperatur hingga 473K

    Energy Technology Data Exchange (ETDEWEB)

    Sunaryo, G R [Reactor Safety Technology Research Centre, National Atomic Energy Agency, Serpong (Indonesia)

    1996-06-01

    Rate constant from the bimolecular reaction of hydrated electron was determined by using radiolysis method. The methanol solution with concentration of 5 x 10{sup -2} dm{sup 3} mol{sup -1} was used as a scavenger of H and OH radicals. The pH was kept by adding the buffer solution of 1.0 x 10{sup -3} dm{sup 3} mol{sup -1} Na{sub 2}HPO{sub 4} + 1.0 x 10{sup 4} dm{sup 3} mol{sup -1} NaH{sub 2}PO{sub 4}. The irradiation was done by using the electron beam which come from linear accelerator 28 MeV with pulse width 10ns and dose of 80 Gy per pulse. The absorbance of hydrated electron was observed at wavelength of 824 nm. By using the kinetic equation the rate reaction constants were obtained. The bimolecular reaction of hydrated electron increase with temperature up to 423K. The activation energy was 19.3 kJ mol{sup -1} and the 2 k (298K) was 1.1 x 10{sup 10} dm{sup 3} mol{sup -1}. Then this bimolecular reaction decrease at temperature higher than 423K and the rate reaction constant at 473K almost similar with that at 298K. (author)

  6. Cross sections of electron loss and capture for beams of O+ in water vapor from the energy range of 0,2 to 1,2 MeV

    International Nuclear Information System (INIS)

    Oliveira, Vitor Jesus de

    2015-01-01

    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 + and the water molecule is a Microchannel Plate (MCP) at the position sensitive anode. The collisions of O + 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 describes

  7. A review of electron-capture and electron-transfer dissociation tandem mass spectrometry in polymer chemistry

    International Nuclear Information System (INIS)

    Hart-Smith, Gene

    2014-01-01

    Graphical abstract: -- Highlights: •ECD and ETD can produce unique and diagnostically useful polymer ion fragmentation data. •The operating principles of ECD and ETD are discussed in relation to other dissociation techniques. •Key characteristics of ECD and ETD spectra, as observed from biological analytes, are discussed. •ECD and ETD analyses are compared to CID analyses for different classes of synthetic polymer. -- Abstract: Mass spectrometry (MS)-based studies of synthetic polymers often characterise detected polymer components using mass data alone. However when mass-based characterisations are ambiguous, tandem MS (MS/MS) offers a means by which additional analytical information may be collected. This review provides a synopsis of two particularly promising methods of dissociating polymer ions during MS/MS: electron-capture and electron-transfer dissociation (ECD and ETD, respectively). The article opens with a summary of the basic characteristics and operating principles of ECD and ETD, and relates these techniques to other methods of dissociating gas-phase ions, such as collision-induced dissociation (CID). Insights into ECD- and ETD-based MS/MS, gained from studies into proteins and peptides, are then discussed in relation to polymer chemistry. Finally, ECD- and ETD-based studies into various classes of polymer are summarised; for each polymer class, ECD- and ETD-derived data are compared to CID-derived data. These discussions identify ECD and ETD as powerful means by which unique and diagnostically useful polymer ion fragmentation data may be generated, and techniques worthy of increased utilisation by the polymer chemistry community

  8. Stability of a slotted ALOHA system with capture effect

    Science.gov (United States)

    Onozato, Yoshikuni; Liu, Jin; Noguchi, Shoichi

    1989-02-01

    The stability of a slotted ALOHA system with capture effect is investigated under a general communication environment where terminals are divided into two groups (low-power and high-power) and the capture effect is modeled by capture probabilities. An approximate analysis is developed using catastrophe theory, in which the effects of system and user parameters on the stability are characterized by the cusp catastrophe. Particular attention is given to the low-power group, since it must bear the strain under the capture effect. The stability conditions of the two groups are given explicitly by bifurcation sets.

  9. Alignment in double capture processes

    International Nuclear Information System (INIS)

    Moretto-Capelle, P.; Benhenni, M.; Bordenave-Montesquieu, A.; Benoit-Cattin, P.; Gleizes, A.

    1993-01-01

    The electron spectra emitted when a double capture occurs in N 7+ +He and Ne 8+ +He systems at 10 qkeV collisional energy, allow us to determine the angular distributions of the 3 ell 3 ell ' lines through a special spectra fitting procedure which includes interferences between neighbouring states. It is found that the doubly excited states populated in double capture processes are generally aligned

  10. DETECTION OF K-RAS AND P53 MUTATIONS IN SPUTUM SAMPLES OF LUNG CANCER PATIENTS USING LASER CAPTURE MICRODISSECTION MICROSCOPE AND MUTATION ANALYSIS

    Science.gov (United States)

    Detection of K-ras and p53 Mutations in Sputum Samples of Lung Cancer Patients Using Laser Capture Microdissection Microscope and Mutation AnalysisPhouthone Keohavong a,*, Wei-Min Gao a, Kui-Cheng Zheng a, Hussam Mady b, Qing Lan c, Mona Melhem b, and Judy Mumford d.<...

  11. Double electron capture in collisions of the helium-like ions N5+, O6+ and Ne8+ with helium atoms

    International Nuclear Information System (INIS)

    Boudjema, M.; Moretto-Capelle, P.; Bordenave-Montesquieu, A.

    1989-01-01

    A fitting procedure of 1s 2 3l3l' lines observed in A (z-2)+ (1s 2 )+He collisions (Z = 7, 8 and 10), at 10 q keV collision energy (q = Z -2) and 10 0 observation angle, allows us to compare new theoretical positions and lifetimes, and experimental electron spectra. It is found that the spin conservation rule holds and that only singlet states are populated in these capture processes. As in N 7+ and O 8+ + He systems, capture into the highest angular momentum 1 G state is favoured in O 6+ and Ne 8+ + He systems and accounts for 26% of the double capture at 10 0 . In N 5+ + He, the L distribution is broader and no L value is clearly predominant. (author)

  12. Enhancing Protein Disulfide Bond Cleavage by UV Excitation and Electron Capture Dissociation for Top-Down Mass Spectrometry

    OpenAIRE

    Wongkongkathep, Piriya; Li, Huilin; Zhang, Xing; Loo, Rachel R. Ogorzalek; Julian, Ryan R.; Loo, Joseph A.

    2015-01-01

    The application of ion pre-activation with 266 nm ultraviolet (UV) laser irradiation combined with electron capture dissociation (ECD) is demonstrated to enhance top-down mass spectrometry sequence coverage of disulfide bond containing proteins. UV-based activation can homolytically cleave a disulfide bond to yield two separated thiol radicals. Activated ECD experiments of insulin and ribonuclease A containing three and four disulfide bonds, respectively, were performed. UV-activation in comb...

  13. Estimating temporary emigration and breeding proportions using capture-recapture data with Pollock's robust design

    Science.gov (United States)

    Kendall, W.L.; Nichols, J.D.; Hines, J.E.

    1997-01-01

    Statistical inference for capture-recapture studies of open animal populations typically relies on the assumption that all emigration from the studied population is permanent. However, there are many instances in which this assumption is unlikely to be met. We define two general models for the process of temporary emigration, completely random and Markovian. We then consider effects of these two types of temporary emigration on Jolly-Seber (Seber 1982) estimators and on estimators arising from the full-likelihood approach of Kendall et al. (1995) to robust design data. Capture-recapture data arising from Pollock's (1982) robust design provide the basis for obtaining unbiased estimates of demographic parameters in the presence of temporary emigration and for estimating the probability of temporary emigration. We present a likelihood-based approach to dealing with temporary emigration that permits estimation under different models of temporary emigration and yields tests for completely random and Markovian emigration. In addition, we use the relationship between capture probability estimates based on closed and open models under completely random temporary emigration to derive three ad hoc estimators for the probability of temporary emigration, two of which should be especially useful in situations where capture probabilities are heterogeneous among individual animals. Ad hoc and full-likelihood estimators are illustrated for small mammal capture-recapture data sets. We believe that these models and estimators will be useful for testing hypotheses about the process of temporary emigration, for estimating demographic parameters in the presence of temporary emigration, and for estimating probabilities of temporary emigration. These latter estimates are frequently of ecological interest as indicators of animal movement and, in some sampling situations, as direct estimates of breeding probabilities and proportions.

  14. CAMAC - supported electronic set-up for the determination of the capture cross section of the reaction 1H(n,d)γ

    International Nuclear Information System (INIS)

    Hutsch, J.; Moeller, K.; Moesner, J.; Neubert, W.; Pilz, W.; Schmidt, G.; Stiehler, T.; Kudin, L.G.; Spiridenkov, E.M.; Volkov, S.S.

    1984-08-01

    After a brief description of the physical problem the experimental apparatus and the electronic set-up for the investigation of the capture reaction 1 H(n,d)γ at E/sub n/ = 25 MeV are described. (author)

  15. Formation of negative hydrogen ion: polarization electron capture and nonthermal shielding.

    Science.gov (United States)

    Ki, Dae-Han; Jung, Young-Dae

    2012-09-07

    The influence of the nonthermal shielding on the formation of the negative hydrogen ion (H(-)) by the polarization electron capture are investigated in partially ionized generalized Lorentzian plasmas. The Bohr-Lindhard method has been applied to obtain the negative hydrogen formation radius and cross section as functions of the collision energy, de Broglie wave length, Debye length, impact parameter, and spectral index of the plasma. The result shows that the nonthermal character of the plasma enhances the formation radius of the negative hydrogen, especially, for small Debye radii. It is found that the nonthermal effect increases the formation cross section of the negative hydrogen. It is also found that the maximum position of the formation cross section approaches to the collision center with an increase of the spectral index. In addition, it is found that the formation cross section significantly decreases with an increase of the Debye length, especially, for small spectral indices.

  16. Formation of negative hydrogen ion: Polarization electron capture and nonthermal shielding

    International Nuclear Information System (INIS)

    Ki, Dae-Han; Jung, Young-Dae

    2012-01-01

    The influence of the nonthermal shielding on the formation of the negative hydrogen ion (H − ) by the polarization electron capture are investigated in partially ionized generalized Lorentzian plasmas. The Bohr-Lindhard method has been applied to obtain the negative hydrogen formation radius and cross section as functions of the collision energy, de Broglie wave length, Debye length, impact parameter, and spectral index of the plasma. The result shows that the nonthermal character of the plasma enhances the formation radius of the negative hydrogen, especially, for small Debye radii. It is found that the nonthermal effect increases the formation cross section of the negative hydrogen. It is also found that the maximum position of the formation cross section approaches to the collision center with an increase of the spectral index. In addition, it is found that the formation cross section significantly decreases with an increase of the Debye length, especially, for small spectral indices.

  17. K-band single-chip electron spin resonance detector.

    Science.gov (United States)

    Anders, Jens; Angerhofer, Alexander; Boero, Giovanni

    2012-04-01

    We report on the design, fabrication, and characterization of an integrated detector for electron spin resonance spectroscopy operating at 27 GHz. The microsystem, consisting of an LC-oscillator and a frequency division module, is integrated onto a single silicon chip using a conventional complementary metal-oxide-semiconductor technology. The achieved room temperature spin sensitivity is about 10(8)spins/G Hz(1/2), with a sensitive volume of about (100 μm)(3). Operation at 77K is also demonstrated. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Alignment in double capture processes

    Energy Technology Data Exchange (ETDEWEB)

    Moretto-Capelle, P.; Benhenni, M.; Bordenave-Montesquieu, A.; Benoit-Cattin, P.; Gleizes, A. (IRSAMC, URA CNRS 770, Univ. Paul Sabatier, 118 rte de Narbonne, 31062 Toulouse Cedex (France))

    1993-06-05

    The electron spectra emitted when a double capture occurs in N[sup 7+]+He and Ne[sup 8+]+He systems at 10 qkeV collisional energy, allow us to determine the angular distributions of the 3[ell]3[ell] [prime] lines through a special spectra fitting procedure which includes interferences between neighbouring states. It is found that the doubly excited states populated in double capture processes are generally aligned.

  19. Lifetime of the long-lived isomer of /sup 236/Np from. cap alpha. -,. beta. - and electron-capture decay measurements

    Energy Technology Data Exchange (ETDEWEB)

    Lindner, M.; Dupzyk, R.J.; Hoff, R.W.; Nagle, R.J. (California Univ., Livermore (USA). Lawrence Livermore National Lab.)

    1981-01-01

    The half-life of long-lived /sup 236/Np, due to ..cap alpha.., ..beta.. and electron-capture decay, was found to be 1.55 x 10/sup 5/ yr. Of all decays, 88% populate excited states in /sup 236/U and 12% populate levels in /sup 236/Pu. Lifetimes measured by growth of the ground states of /sup 236/U and /sup 236/Pu agree with values from corresponding ..gamma.. de-excitations in these daughter nuclei. Therefore, nearly all the electron-capture decays populate the 6/sup +/ level of the ground-state band in /sup 236/U. Similarly, essentially all the ..beta../sup -/ decay populates an analogous 6/sup +/ level in /sup 236/Pu, which de-excites through a previously unreported transition of 158.3 keV. If a very week ..gamma..-ray at 894 keV can be ascribed to a level in /sup 232/U populated by ..beta.. decay of /sup 232/Pa, its existence establishes a 0.2% ..cap alpha..-branching decay in /sup 236/Np.

  20. Thermal neutron capture cross sections resonance integrals and g-factors

    International Nuclear Information System (INIS)

    Mughabghab, S.F.

    2003-02-01

    The thermal radiative capture cross sections and resonance integrals of elements and isotopes with atomic numbers from 1 to 83 (as well as 232 Th and 238 U) have been re-evaluated by taking into consideration all known pertinent data published since 1979. This work has been undertaken as part of an IAEA co-ordinated research project on 'Prompt capture gamma-ray activation analysis'. Westcott g-factors for radiative capture cross sections at a temperature of 300K were computed by utilizing the INTER code and ENDF-B/VI (Release 8) library files. The temperature dependence of the Westcott g-factor is illustrated for 113 Cd, 124 Xe and 157 Gd at temperatures of 150, 294 and 400K. Comparisons have also been made of the newly evaluated capture cross sections of 6 Li, 7 Li, 12 C and 207 Pb with those determined by the k 0 method. (author)

  1. Fabrication of Nonvolatile Memory Effects in High-k Dielectric Thin Films Using Electron Irradiation

    International Nuclear Information System (INIS)

    Park, Chanrock; Cho, Daehee; Kim, Jeongeun; Hwang, Jinha

    2010-01-01

    Electron Irradiation can be applied towards nano-floating gate memories which are recognized as one of the next-generation nonvolatile memory semiconductors. NFGMs can overcome the preexisting limitations encountered in Dynamic Random Access Memories and Flash memories with the excellent advantages, i. e. high-density information storage, high response speed, high compactness, etc. The traditional nano-floating gate memories are fabricated through multi-layered nano structures of the dissimilar materials where the charge-trapping portions are sandwiched into the high-k dielectrics. However, this work reports the unique nonvolatile responses in single-layered high-k dielectric thin films if irradiated with highly accelerated electron beams. The implications of the electron irradiation will be discussed towards high-performance nano-floating gate memories

  2. The perception of probability.

    Science.gov (United States)

    Gallistel, C R; Krishan, Monika; Liu, Ye; Miller, Reilly; Latham, Peter E

    2014-01-01

    We present a computational model to explain the results from experiments in which subjects estimate the hidden probability parameter of a stepwise nonstationary Bernoulli process outcome by outcome. The model captures the following results qualitatively and quantitatively, with only 2 free parameters: (a) Subjects do not update their estimate after each outcome; they step from one estimate to another at irregular intervals. (b) The joint distribution of step widths and heights cannot be explained on the assumption that a threshold amount of change must be exceeded in order for them to indicate a change in their perception. (c) The mapping of observed probability to the median perceived probability is the identity function over the full range of probabilities. (d) Precision (how close estimates are to the best possible estimate) is good and constant over the full range. (e) Subjects quickly detect substantial changes in the hidden probability parameter. (f) The perceived probability sometimes changes dramatically from one observation to the next. (g) Subjects sometimes have second thoughts about a previous change perception, after observing further outcomes. (h) The frequency with which they perceive changes moves in the direction of the true frequency over sessions. (Explaining this finding requires 2 additional parametric assumptions.) The model treats the perception of the current probability as a by-product of the construction of a compact encoding of the experienced sequence in terms of its change points. It illustrates the why and the how of intermittent Bayesian belief updating and retrospective revision in simple perception. It suggests a reinterpretation of findings in the recent literature on the neurobiology of decision making. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  3. Iodide- and bromide-specific electron-capture/photodetachment-modulated detector for the trace analysis of halocarbon mixtures

    International Nuclear Information System (INIS)

    Mock, R.S.; Grimsrud, E.P.

    1988-01-01

    The use of photodetachment (PD) of electrons from negative ions in a pulsed electron capture detector (ECD) is described. By passing a chopped light beam through the ECD and amplification of the modulated component of the ECD signal, the photodetachment-modulated (PDM) pulsed ECD can be made to respond selectively and sensitively to iodine- containing hydrocarbons alone, or to iodine- and bromine-containing hydrocarbons in the presence of chlorinated hydrocarbons. The detection limit of the iodide/bromide-specific mode of the PDM-ECD to CH 3 I is shown to be competitive with that of the normal mode of the pulsed ECD. This detection mode of the ECD is shown to be of great assistance in the gas chromatographic analysis of organobromides and organoiodides in complex mixtures which contain a large number of organochlorides

  4. Formation of S-type planets in close binaries: scattering induced tidal capture of circumbinary planets

    Science.gov (United States)

    Gong, Yan-Xiang; Ji, Jianghui

    2018-05-01

    Although several S-type and P-type planets in binary systems were discovered in past years, S-type planets have not yet been found in close binaries with an orbital separation not more than 5 au. Recent studies suggest that S-type planets in close binaries may be detected through high-accuracy observations. However, nowadays planet formation theories imply that it is difficult for S-type planets in close binaries systems to form in situ. In this work, we extensively perform numerical simulations to explore scenarios of planet-planet scattering among circumbinary planets and subsequent tidal capture in various binary configurations, to examine whether the mechanism can play a part in producing such kind of planets. Our results show that this mechanism is robust. The maximum capture probability is ˜10%, which can be comparable to the tidal capture probability of hot Jupiters in single star systems. The capture probability is related to binary configurations, where a smaller eccentricity or a low mass ratio of the binary will lead to a larger probability of capture, and vice versa. Furthermore, we find that S-type planets with retrograde orbits can be naturally produced via capture process. These planets on retrograde orbits can help us distinguish in situ formation and post-capture origin for S-type planet in close binaries systems. The forthcoming missions (PLATO) will provide the opportunity and feasibility to detect such planets. Our work provides several suggestions for selecting target binaries in search for S-type planets in the near future.

  5. Preclinical studies on gadolinium neutron capture therapy

    International Nuclear Information System (INIS)

    Akine, Yasuyuki

    1994-01-01

    Gadolinium neutron capture therapy is based on radiations (photons and electrons) produced in the tumor by a nuclear reaction between gadolinium and lower-energy neutrons. Studies with Chinese hamster cells have shown that the radiation effect resulting from gadolinium neutron capture reactions is mostly of low LET and that released electrons are the significant component in the over-all dose. Biological dosimetry revealed that the dose does not seem to increase in proportion to the gadolinium concentration, leading to a conclusion that there is a range of gadolinium concentrations most efficient for gadolinium neutron capture therapy. The in vivo studies with transplantable tumors in mice and rabbits have revealed that close contact between gadolinium and the cell is not necessarily required for cell inactivation and that gadolinium delivery selective to tumors is crucial. The results show that the potential of gadolinium neutron capture therapy as a therapeutic modality appears very promising. (author)

  6. Soybean P34 Probable Thiol Protease Probably Has Proteolytic Activity on Oleosins.

    Science.gov (United States)

    Zhao, Luping; Kong, Xiangzhen; Zhang, Caimeng; Hua, Yufei; Chen, Yeming

    2017-07-19

    P34 probable thiol protease (P34) and Gly m Bd 30K (30K) show high relationship with the protease of 24 kDa oleosin of soybean oil bodies. In this study, 9 day germinated soybean was used to separate bioprocessed P34 (P32) from bioprocessed 30K (28K). Interestingly, P32 existed as dimer, whereas 28K existed as monomer; a P32-rich sample had proteolytic activity and high cleavage site specificity (Lys-Thr of 24 kDa oleosin), whereas a 28K-rich sample showed low proteolytic activity; the P32-rich sample contained one thiol protease. After mixing with purified oil bodies, all P32 dimers were dissociated and bound to 24 kDa oleosins to form P32-24 kDa oleosin complexes. By incubation, 24 kDa oleosin was preferentially hydrolyzed, and two hydrolyzed products (HPs; 17 and 7 kDa) were confirmed. After most of 24 kDa oleosin was hydrolyzed, some P32 existed as dimer, and the other as P32-17 kDa HP. It was suggested that P32 was the protease.

  7. Single electron capture differential cross section in H+ + He collisions at intermediate and high collision energies

    International Nuclear Information System (INIS)

    Abufager, P N; Fainstein, P D; MartInez, A E; Rivarola, R D

    2005-01-01

    The generalized continuum distorted wave-eikonal initial state (CDW-EIS II) approximation is employed to study differential cross sections (DCS) for single electron capture in H + + He collisions at intermediate and high energies. Present results are compared with theoretical calculations obtained using the previous CDW-EIS formulation in order to show the importance of the description of the bound and continuum target states in the entrance and exit channels, respectively. Both DCS are also shown together with other theoretical results and with experimental data

  8. Coiled-coil formation of the membrane-fusion K/E peptides viewed by electron paramagnetic resonance.

    Directory of Open Access Journals (Sweden)

    Pravin Kumar

    Full Text Available The interaction of the complementary K (Ac-(KIAALKE3-GW-NH2 and E (Ac-(EIAALEK3-GY-NH2 peptides, components of the zipper of an artificial membrane fusion system (Robson Marsden H. et al. Angew Chemie Int Ed. 2009 is investigated by electron paramagnetic resonance (EPR. By frozen solution continuous-wave EPR and double electron-electron resonance (DEER, the distance between spin labels attached to the K- and to the E-peptide is measured. Three constructs of spin-labelled K- and E-peptides are used in five combinations for low temperature investigations. The K/E heterodimers are found to be parallel, in agreement with previous studies. Also, K homodimers in parallel orientation were observed, a finding that was not reported before. Comparison to room-temperature, solution EPR shows that the latter method is less specific to detect this peptide-peptide interaction. Combining frozen solution cw-EPR for short distances (1.8 nm to 2.0 nm and DEER for longer distances thus proves versatile to detect the zipper interaction in membrane fusion. As the methodology can be applied to membrane samples, the approach presented suggests itself for in-situ studies of the complete membrane fusion process, opening up new avenues for the study of membrane fusion.

  9. Electron-impact-induced K plus M shell ionization in solid targets of medium-Z elements studied by means of high-resolution x-ray spectroscopy

    International Nuclear Information System (INIS)

    Ludziejewski, T.; Rymuza, P.; Sujkowski, Z.; Borchert, G.; Dousse, J.; Rheme, C.; Polasik, M.

    1996-01-01

    The Kβ 2 x-ray spectra of zirconium, niobium, molybdenum, and palladium bombarded by 150 and 300 keV electrons were measured with a high-resolution transmission curved crystal spectrometer. Multiconfiguration Dirac-Fock calculations were used for the decomposition of the experimental spectra into the Kβ 2 M 0 (diagram) and Kβ 2 M 1 (satellite) components. The probabilities of energy dependent (direct Coulomb and two-step) processes were estimated from the differences in the satellite line yields for electrons and photons. The satellite yields are found to be considerably enhanced in comparison with those for the proton-induced ionization recently measured and analyzed in the same way [T. Ludziejewski et al., Phys. Rev. A 52, 2791 (1995)]. This result indicates the importance of multielectron effects in the K plus M shell ionization by energetic projectiles. copyright 1996 The American Physical Society

  10. Isotope separation by photoselective dissociative electron

    International Nuclear Information System (INIS)

    Stevens, C.G.

    1978-01-01

    A method of separating isotopes based on photoselective electron capture dissociation of molecules having an electron capture cross section dependence on the vibrational state of the molecule is described. A molecular isotope source material is irradiated to selectively excite those molecules containing a desired isotope to a predetermined vibrational state having associated therewith an electron capture energy region substantially non-overlapping with the electron capture energy ranges associated with the lowest vibration states of the molecules. The isotope source is also subjected to electrons having an energy corresponding to the non-overlapping electron capture region whereby the selectively excited molecules preferentially capture electrons and dissociate into negative ions and neutrals. The desired isotope may be in the negative ion product or in the neutral product depending upon the mechanism of dissociation of the particular isotope source used. The dissociation product enriched in the desired isotope is then separated from the reaction system by conventional means. Specifically, 235 UF 6 is separated from a UF 6 mixture by selective excitation followed by dissociative electron capture into 235 UF 5 - and F

  11. Transition probabilities of some Si II lines obtained by laser produced plasma emission

    International Nuclear Information System (INIS)

    Blanco, F.; Botho, B.; Campos, J.

    1995-01-01

    The absolute transition probabilities for 28 Si II spectral lines have been determined by measurement of emission line intensities from laser-produced plasmas of Si in Ar and Kr atmospheres. The studied plasma has a temperature of about 2 . 10 4 K and 10 17 cm -3 electron density. The local thermodynamic equilibrium conditions and plasma homogeneity have been checked. The results are compared with the available experimental and theoretical data and with present Hartree-Fock calculations in LS coupling. (orig.)

  12. Probability shapes perceptual precision: A study in orientation estimation.

    Science.gov (United States)

    Jabar, Syaheed B; Anderson, Britt

    2015-12-01

    Probability is known to affect perceptual estimations, but an understanding of mechanisms is lacking. Moving beyond binary classification tasks, we had naive participants report the orientation of briefly viewed gratings where we systematically manipulated contingent probability. Participants rapidly developed faster and more precise estimations for high-probability tilts. The shapes of their error distributions, as indexed by a kurtosis measure, also showed a distortion from Gaussian. This kurtosis metric was robust, capturing probability effects that were graded, contextual, and varying as a function of stimulus orientation. Our data can be understood as a probability-induced reduction in the variability or "shape" of estimation errors, as would be expected if probability affects the perceptual representations. As probability manipulations are an implicit component of many endogenous cuing paradigms, changes at the perceptual level could account for changes in performance that might have traditionally been ascribed to "attention." (c) 2015 APA, all rights reserved).

  13. The Bells' Capture note TH-3054-CERN

    Energy Technology Data Exchange (ETDEWEB)

    Hartouni, Ed P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-01-29

    This document revisits the paper by M. Bell and J. S. Bell “Capture of Cooling Electrons by Cool Protons” TH-3054-CERN (March 30, 1981). I expand the treatment to include e+e- capture.

  14. Differential charge transfer and continuum electron capture studies for ions in atomic hydrogen. Final report, August 1, 1979-September 31, 1983

    International Nuclear Information System (INIS)

    Sellin, I.A.; Elston, S.B.

    1983-01-01

    A final technical narrative is given of progress and results obtained during the period August 1, 1979 through September 30, 1983 in a project designed to test existing theories of electron capture to continuum states of fully stripped nuclei traversing atomic hydrogen targets. 5 references

  15. State-selective electron capture in collisions of ground and metastable O2+ ions with H(1s)

    International Nuclear Information System (INIS)

    Cabello, C N; Errea, L F; Fernandez, L; Mendez, L; Macias, A; Rabadan, I; Riera, A

    2003-01-01

    An ab initio calculation of the electron capture cross sections for collisions of ground and metastable states of O 2+ with H(1s) is presented. For impact energies between 0.125 and 3.4 keV amu -1 , we find good agreement between the cross sections from the ground state ion with the mixed beam experimental data of Phaneuf et al (Phaneuf A, Alvarez I, Meyer F W and Crandall D H 1982 Phys. Rev. A 26 1892)

  16. Electron emission from transfer ionization reaction in 30 keV amu‑1 He 2+ on Ar collision

    Science.gov (United States)

    Amaya-Tapia, A.; Antillón, A.; Estrada, C. D.

    2018-06-01

    A model is presented that describes the transfer ionization process in H{e}2++Ar collision at a projectile energy of 30 keV amu‑1. It is based on a semiclassical independent-particle close-coupling method that yields a reasonable agreement between calculated and experimental values of the total single-ionization and single-capture cross sections. It is found that the transfer ionization reaction is predominantly carried out through simultaneous capture and ionization, rather than by sequential processes. The transfer-ionization differential cross section in energy that is obtained satisfactorily reproduces the global behavior of the experimental data. Additionally, the probabilities of capture and ionization as function of the impact parameter for H{e}2++A{r}+ and H{e}++A{r}+ collisions are calculated, as far as we know, for the first time. The results suggest that the model captures essential elements that describe the two-electron transfer ionization process and could be applied to systems and processes of two electrons.

  17. Studies on chemical effects on x-ray intensity ratios of K/sub β//K/sub α/ in nuclear decay of technetium nuclides /sup 99m/Tc, /sup 97m/Tc, and /sup 95m/Tc

    International Nuclear Information System (INIS)

    Yamoto, I.; Kaji, H.; Yoshihara, K.

    1986-01-01

    Chemical effects of characteristic x-ray intensity ratios of K/sub β//K/sub α/ were investigated for the second d-group element Tc in the decay processes /sup 99m/Tc → 99 Tc (two-step isomeric transition), /sup 97m/Tc → 97 Tc (one-step isomeric transition), and /sup 95m/Tc → 95 Mo (electron capture). The objective nuclides were produced by (n, γ)β - , (d, xn), and (α, xn) reactions and were chemically separated from the target materials. The x rays were measured with a pure germanium detector, and the K/sub β/ x rays were analyzed into the two components K/sup prime//sub beta1/ and K/sup //sub beta2/ using a computer program. The chemical effect of the intensity ratio was more pronounced for K/sup prime//sub beta2//K/sub α/ than for K/sup //sub beta1//K/sub α/, as expected. The effect was larger in KTcO 4 than in the other species of Tc 2 S 7 , K 2 TcCl 6 , and Tc metal. The effect in the two-step isomeric transition in /sup 99m/Tc was found to be larger than in the one-step isomeric transition in /sup 97m/Tc. The effect in the electron capture in /sup 95m/Tc (Mo x rays) was similar to that in /sup 97m/Tc although the ratio K/sub β//K/sub α/ was smaller in /sup 95m/Tc than in /sup 97m/Tc, reflecting the change of nuclear charge. The tendency of the observed chemical effect was explained by taking into account the interfering factors which involve Pauling's ionicity in chemical bonding between Tc and its counter atom

  18. Double capture in the O/sup 8+/ + He collision investigated by electron spectroscopy (80 keV, 10 deg)

    Energy Technology Data Exchange (ETDEWEB)

    Moretto-Capelle, P.; Benoit-Cattin, P.; Bordenave-Montesquieu, A.; Boudjema, M.; Gleizes, A.; Oza, D.H.; Dousson, S.; Hitz, D.

    1989-01-28

    Double capture into (3,n) autoionising states of O/sup 6+/ is observed in the O/sup 8+/ + He collision system by electron spectroscopy at 80 keV, 10/sup 0/. A comparison of the experimental results with theoretical positions and lifetimes allows the (3,3) states as well as three groups of (3,4) states to be identified. The present experimental findings are compared with earlier data for the N/sup 7+/ + He and Ne/sup 8+/(1s/sup 2/) + He systems. The influence of the core of the multicharged ion is studied by examining the O/sup 8+/ and Ne/sup 8+/(1s/sup 2/) results. The total double capture cross section is found to be large and it is compared with available experimental and theoretical data.

  19. Electronic States of High-k Oxides in Gate Stack Structures

    Science.gov (United States)

    Zhu, Chiyu

    In this dissertation, in-situ X-ray and ultraviolet photoemission spectroscopy have been employed to study the interface chemistry and electronic structure of potential high-k gate stack materials. In these gate stack materials, HfO2 and La2O3 are selected as high-k dielectrics, VO2 and ZnO serve as potential channel layer materials. The gate stack structures have been prepared using a reactive electron beam system and a plasma enhanced atomic layer deposition system. Three interrelated issues represent the central themes of the research: 1) the interface band alignment, 2) candidate high-k materials, and 3) band bending, internal electric fields, and charge transfer. 1) The most highlighted issue is the band alignment of specific high-k structures. Band alignment relationships were deduced by analysis of XPS and UPS spectra for three different structures: a) HfO2/VO2/SiO2/Si, b) HfO 2-La2O3/ZnO/SiO2/Si, and c) HfO 2/VO2/ HfO2/SiO2/Si. The valence band offset of HfO2/VO2, ZnO/SiO2 and HfO 2/SiO2 are determined to be 3.4 +/- 0.1, 1.5 +/- 0.1, and 0.7 +/- 0.1 eV. The valence band offset between HfO2-La2O3 and ZnO was almost negligible. Two band alignment models, the electron affinity model and the charge neutrality level model, are discussed. The results show the charge neutrality model is preferred to describe these structures. 2) High-k candidate materials were studied through comparison of pure Hf oxide, pure La oxide, and alloyed Hf-La oxide films. An issue with the application of pure HfO2 is crystallization which may increase the leakage current in gate stack structures. An issue with the application of pure La2O3 is the presence of carbon contamination in the film. Our study shows that the alloyed Hf-La oxide films exhibit an amorphous structure along with reduced carbon contamination. 3) Band bending and internal electric fields in the gate stack structure were observed by XPS and UPS and indicate the charge transfer during the growth and process. The oxygen

  20. PbSnTe:In compound: Electron capture levels, galvanomagnetic properties, and THz sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Ishchenko, D. V., E-mail: miracle4348@gmail.com; Klimov, A. E.; Shumsky, V. N.; Epov, V. S. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation)

    2016-12-15

    A model of the Pb{sub 1–x}Sn{sub x}Te:In compound, based on concepts of the theory of disordered systems is considered. The temperature dependences of the Fermi-level position and carrier concentration are calculated depending on the indium doping level and are compared with experimental data. The transient current–voltage characteristics are calculated in the mode of injection from the contact and current limitation by space charge at various voltage-variation rates. The data obtained are compared with the experiments. It is demonstrated that the shape of the characteristics is controlled by the parameters of electron capture at localized states. Photocurrent relaxation in a magnetic field is studied, and the mechanism of such relaxation is discussed under the assumption of the magnetic freezing of carriers.

  1. Indication for a K/sup π/ = 0- octupole band in 150Nd from electron scattering

    International Nuclear Information System (INIS)

    Creswell, C.; Hirsch, A.; Bertozzi, W.; Heisenberg, J.; Kowalski, S.; Sargent, C.P.; Turchinetz, W.; Dieperink, A.

    1978-01-01

    Recent electron scattering results on the 0.850 MeV level of 150 Nd, when analyzed in terms of the interacting boson model, are inconsistent with the interpretation of this level as a pure J/sup π/(K) = 2 + (0) state. Very recent (n,n'γ) work has shown this level to be a 1 - , 2 + doublet. Assuming this level to be the band head of a ''K/sup π/ = 0 - '' octupole band, a simple model is used to predict electron scattering form factors for the 0.850 MeV state and a 3 - octupole level observed at 0.931 MeV. Comparison is made between these predicted form factors and recent electron scattering data

  2. Probability and information theory, with applications to radar

    CERN Document Server

    Woodward, P M; Higinbotham, W

    1964-01-01

    Electronics and Instrumentation, Second Edition, Volume 3: Probability and Information Theory with Applications to Radar provides information pertinent to the development on research carried out in electronics and applied physics. This book presents the established mathematical techniques that provide the code in which so much of the mathematical theory of electronics and radar is expressed.Organized into eight chapters, this edition begins with an overview of the geometry of probability distributions in which moments play a significant role. This text then examines the mathematical methods in

  3. Does the Finite Size of Electrons Affect Quantum Noise in Electronic Devices?

    International Nuclear Information System (INIS)

    Colomés, E; Marian, D; Oriols, X

    2015-01-01

    Quantum transport is commonly studied with the use of quasi-particle infinite- extended states. This leads to a powerful formalism, the scattering-states theory, able to capture in compact formulas quantities of interest, such as average current, noise, etc.. However, when investigating the spatial size-dependence of quasi-particle wave packets in quantum noise with exchange and tunneling, unexpected new terms appear in the quantum noise expression. For this purpose, the two particle transmission and reflection probabilities for two initial one-particle wave packets (with opposite central momentums) spatially localized at each side of a potential barrier are studied. After the interaction, each wave packet splits into a transmitted and a reflected component. It can be shown that the probability of detecting two (identically injected) electrons at the same side of the barrier is different from zero in very common (single or double barrier) scenarios. This originates an increase of quantum noise which cannot be obtained through the scattering states formalism. (paper)

  4. 5 MeV 300 kW electron accelerator project

    International Nuclear Information System (INIS)

    Auslender, V.L.; Cheskidov, V.G.; Gornakov, I.V.

    2004-01-01

    The paper presents a project of a high power linear accelerator for industrial applications. The accelerator has a modular structure and consists of the chain of accelerating cavities connected by the axis-located coupling cavities with coupling slots in the common walls. Main parameters of the accelerator are: operating frequency of 176 MHz, electron energy of up to 5 MeV, average beam power of 300 kW. The required RF pulse power can be supplied by the TH628 diacrode

  5. Mass measurements of neutron rich isotopes in the Fe region and electron capture processes in neutron star crusts

    International Nuclear Information System (INIS)

    Estrade, Alfredo; Matos, M.; Schatz, Hendrik; Amthor, A.M.; Beard, Mary; Brown, Edward; Bazin, D.; Becerril, A.; Elliot, T.; Gade, A.; Galaviz, D.; Gupta, Sanjib; Hix, William Raphael; Lau, Rita; Moeller, Peter; Pereira, J.; Portillo, M.; Rogers, A.M.; Shapira, Dan; Smith, E.; Stolz, A.; Wallace, M.; Wiescher, Michael

    2011-01-01

    Experimental knowledge of nuclear masses of exotic nuclei is important for understanding nuclear structure far from the valley of stability, and as a direct input into astrophysical models. Electron capture processes in the crust of accreting neutron stars have been proposed as a heat source that can affect the thermal structure of the star. Nuclear masses of very neutron-rich nuclides are necessary inputs to model the electron capture process. The time-of-flight (TOF) mass measurement technique allows measurements on very short-lived nuclei. It has been effectively applied using the fast fragment beams produced at the National Superconducting Cyclotron Lab (NSCL) to reach masses very far from stability. Measurements were performed for neutron-rich isotopes in the region of the N=32 and N=40 subshells, which coincides with the mass range of carbon superburst ashes. We discuss reaction network calculations performed to investigate the impact of our new measurements and to compare the effect of using different global mass models in the calculations. It is observed that the process is sensitive to the differences in the odd-even mass staggering predicted by the mass models, and our new result for 66Mn has a significant impact on the distribution of heat sources in the crust.

  6. Electron capture on 20Ne and the ultimate fate of stars in the mass range 8-10 M⊙

    International Nuclear Information System (INIS)

    Kirsebom, Oliver S.; Cederkall, Joakim; Jenkins, David G.; Joshi, Pankaj; Julin, Rauno; Kankainen, Anu; Trzaska, Wladyslaw H.; Kibedi, Tibor; Tengblad, Olof

    2016-01-01

    Knowledge of the electron-capture rate on 20 Ne is of critical importance to understand the final evolution of stars in the mass range 8-10M⊙. A recent study has highlighted the importance of the second-forbidden transition between the ground states of 20 Ne and 20 F, which is believed to dominate the capture rate in an important temperature-density range. The strength of this transition is, however, not well constrained, neither experimentally nor theoretically, making an experimental determination highly desirable. The transition strength can be determined from the branching ratio of the inverse transition in the decay of 20 F, for which the experimental upper limit is 10 -5 , while the most recent theoretical prediction is 1.3 x 10 -6 . To facilitate an experimental determination of the branching ratio we are refurbishing an intermediate-image magnetic spectrometer capable of focusing 7 MeV electrons, and designing a scintillator detector surrounded by an active cosmic-ray veto shield, which will serve as an energy- dispersive device at the focal plane. In this contribution, GEANT4 simulations of the expected performance of the setup will be presented and the astrophysical motivation for the experiment will be discussed. (author)

  7. Results from Super-Kamiokande and K2K

    Indian Academy of Sciences (India)

    The probability of flavor oscillation (in the simplest, two-component case) is ..... K2K had collected about half of its total planned protons-on-target when the accident at ... [14] Design, construction, and operation of SciFi tracking detector for K2K ...

  8. Total cross-sections for single electron capture from H, He and H2 targets by impact of Be4+ and B5+ ions

    International Nuclear Information System (INIS)

    Busnengo, H.F.; Rivarola, R.D.; Universidad Nacional de Rosario; Rosario Univ. Nacional

    1996-01-01

    Single electron capture from H, He and H 2 targets by impact of Be 4+ and B 5+ projectiles is studied for intermediate and high collision energies. Total cross-sections are calculated using the continuum distorted wave-eikonal final state model. Theoretical results corresponding to capture to selective final bound states and to all final states are presented for impact energies ranging from 50 keV/amu to 3 MeV/amu. A comparison with available experimental data is also shown. (orig.)

  9. Development of methods for activity determination for radionuclides with double decay emission β- β+ / electron capture - application to the standardization of 192Ir, 152Eu and 186 Re

    International Nuclear Information System (INIS)

    Hilario, Katia Aparecida Fonseca

    2002-01-01

    In the present work alternative procedures have been developed for standardization of radionuclides with double decay, β - β + / electron capture using the 4πβ-γ coincidence technique, applying different systems. Two 4πβ-γ coincidence systems were used: one with a 4π gas-flow proportional counter coupled to a pair of NaI(Tl) scintillators and the other one with the same type of proportional counter coupled to HPGe detector. The radionuclides selected for this standardization, due to great interest in nuclear medicine, detector calibration and industrial radiography, were 192 Ir, 152 Eu and 186 Re. The first and the second were part of international comparisons sponsored by the Bureau International des Poids et Mesures (BIPM), France, who supplied the radioactive solution. For 186 Re, the gamma-ray emission probability per decay was measured by means REGe spectrometer system, previously calibrated with standard ampoules. All the uncertainties involved were treated rigorously, by means of covariance analysis. (author)

  10. Some ways for the investigation of the solar modulation of cosmic electrons; Moyens d'etude de la modulation solaire des electrons cosmiques

    Energy Technology Data Exchange (ETDEWEB)

    Mercier, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-07-01

    In this report, we are investigating the solar modulation of cosmic electrons, in different ways. By comparing the calculated intensity with the measured intensity of positrons, we can evaluate the solar modulation of positrons, hence the modulation of negatons, since the modulation of negatons is probably the same that for positrons. By comparing the electron spectrum in interstellar space needed to explain the galactic background radio emission with that observed near the earth, we can deduce information about the modulation of electrons. We can investigate the modulation through the observation of its variations during the solar cycle. This different ways lead us to compatible results. In spite of the fact that the precision of the experimental data is poor, the modulation can be represented by: a constant or a form in exp(- K/Ro{beta}) under the rigidity Ro {approx_equal} 0,5 BV; a form in exp(- K/R) or exp(- K/R{beta}) above this rigidity. In addition, the investigation of both electrons and protons displays that the diffusion-convection theory is inadequate to explain all the features of the solar modulation. (author) [French] Dans le present rapport, nous etudions la modulation solaire des electrons cosmiques a l'aide de plusieurs methodes. Par comparaison entre l'intensite calculee et l'intensite mesuree des positons, on peut evaluer la modulation solaire des positons, et aussi des negatons, puisque la modulation des negatons est probablement la meme que celle des positons. Par le calcul, a partir du bruit de fond radio, du flux des electrons a l'exterieur du systeme solaire et sa confrontation avec le flux observe a l'orbite de la Terre permet l'etude de la modulation solaire des electrons. On peut aussi analyser ce phenomene de modulation pour l'etude de ses variations au cours du cycle solaire. Ces diverses methodes donnent des resultats compatibles. En depit de la precision mediocre des donnees experimentales, on peut caracteriser la modulation par: une

  11. Exploration on anion ordering, optical properties and electronic structure in K3WO3F3 elpasolite

    International Nuclear Information System (INIS)

    Atuchin, V.V.; Isaenko, L.I.; Kesler, V.G.; Lin, Z.S.; Molokeev, M.S.; Yelisseyev, A.P.; Zhurkov, S.A.

    2012-01-01

    Room-temperature modification of potassium oxyfluorotungstate, G2-K 3 WO 3 F 3 , has been prepared by low-temperature chemical route and single crystal growth. Wide optical transparency range of 0.3–9.4 μm and forbidden band gap E g =4.32 eV have been obtained for G2-K 3 WO 3 F 3 crystal. Meanwhile, its electronic structure has been calculated with the first-principles calculations. The good agreement between the theorectical and experimental results have been achieved. Furthermore, G2-K 3 WO 3 F 3 is predicted to possess the relatively large nonlinear optical coefficients. - Graphical abstract: Using the cm-size K 3 WO 3 F 3 crystal (left upper), the transmission spectrum (right upper) and XPS valence electronic states (left lower) were measured, agreed with the ab initio results (right lower). Highlights: ► The cm-size G2-K 3 WO 3 F 3 single crystals are obtained. ► Optical absorption edge and transmission range are defined for G2-K 3 WO 3 F 3 crystal. ► Crystal structures of all known K 3 WO 3 F 3 polymorph modifications are determined. ► Experimental electronic structure is consistent with the first-principles result. ► G2-K 3 WO 3 F 3 is predicted as a crystal with large NLO coefficients.

  12. Electron capture detection of sulphur gases in carbon dioxide at the parts-per-billion level

    International Nuclear Information System (INIS)

    Pick, M.E.

    1979-01-01

    A gas chromatograph with an electron capture detector has been used to determine sulphur gases in CO 2 at the parts-per-billion level, with particular application to the analysis of coolant from CO 2 cooled nuclear reactors. For COS, CS 2 , CH 3 SH, H 2 S and (CH 3 ) 2 S 2 the detector has a sensitivity comparable with the more commonly used flame photometric detector, but it is much less sensitive towards (CH 3 ) 2 S and thiophene. In addition, the paper describes a simple method for trapping sulphur gases which might enable detection of sub parts-per-billion levels of sulphur compounds. (Auth.)

  13. Comparison between the mechanical and radiative electron-capture processes at high energies

    International Nuclear Information System (INIS)

    Gonzalez, A.D.; Miraglia, J.E.

    1984-01-01

    The ground-state--ground-state mechanical and radiative electron-capture processes are studied at very high, but not relativistic, projectile velocities. Three-body calculations were carried out with use of the continuum distorted-wave theoretical method for both processes. Total cross sections and final-atom angular distributions were computed, and the importance of each mechanism examined. For total cross sections, the numerical results reaffirm that the radiative process is the predominant mechanism at very high projectile energies. For a given incident charge, the range of projectile energies in which the nonrelativistic radiative mechanism is the most important decreases as the target charge increases. It is found that the radiative mechanism produces a very sharp final-atom angular distribution in the forward direction. When both processes, the radiative and mechanical, give the same total cross section, the calculations show that the radiative differential cross section in the forward direction is almost 2 orders of magnitude larger than the mechanical one

  14. Kinetic energy of shakeoff atomic electrons from 37K β+ decay

    Science.gov (United States)

    Behr, J. A.; Gorelov, A.; Farfan, C.; Smale, S.; Olchanski, K.; Kurchananov, L.; Anholm, M.; Behling, R. S.; Fenker, B.; Shidling, P. D.; Mehlman, M.; Melconian, D.; Ashery, D.; Gwinner, G.; Trinat Collaboration

    2013-10-01

    We have measured the kinetic energies from 0 to 30 eV of atomic shakeoff electrons from the β+ decay of 37K. Despite much experimental and theoretical work on the distribution of final ion charge states, shakeoff electrons from β- decay have only been measured with energies above 150 eV [Mitrokhovich, Nucl. Phys. Atom. Energy, 11, 125 (2010)]. We use our magneto-optical trap's time-varying magnetic quadrupole field combined with a uniform electric field as a spectrometer. Our result has more 15 eV electrons than a model using the sudden approximation and hydrogenic wavefunctions [Levinger, Phys. Rev. 90, 11 (1958)]. The total energy carried away by electrons is, as expected, a negligible correction to superallowed Ft values. Understanding the energy of these low-energy electrons is important for their use in precision β decay to select events coming from trapped atoms and start time-of-flight for the recoil ions. Our results could provide a benchmark for shakeoff electron calculations used for biological radiation damage [Lee, Comp. Math. Meth in Medicine doi:10.1155/2012/651475]. Support: NSERC, NRC through TRIUMF, DOE ER41747 ER40773, State of Texas, Israel Science Foundation.

  15. Probability Theory Plus Noise: Descriptive Estimation and Inferential Judgment.

    Science.gov (United States)

    Costello, Fintan; Watts, Paul

    2018-01-01

    We describe a computational model of two central aspects of people's probabilistic reasoning: descriptive probability estimation and inferential probability judgment. This model assumes that people's reasoning follows standard frequentist probability theory, but it is subject to random noise. This random noise has a regressive effect in descriptive probability estimation, moving probability estimates away from normative probabilities and toward the center of the probability scale. This random noise has an anti-regressive effect in inferential judgement, however. These regressive and anti-regressive effects explain various reliable and systematic biases seen in people's descriptive probability estimation and inferential probability judgment. This model predicts that these contrary effects will tend to cancel out in tasks that involve both descriptive estimation and inferential judgement, leading to unbiased responses in those tasks. We test this model by applying it to one such task, described by Gallistel et al. ). Participants' median responses in this task were unbiased, agreeing with normative probability theory over the full range of responses. Our model captures the pattern of unbiased responses in this task, while simultaneously explaining systematic biases away from normatively correct probabilities seen in other tasks. Copyright © 2018 Cognitive Science Society, Inc.

  16. PROBABLE CHARACTERISTICS ОF ELECTROMAGNETIC FIELD ENVIRONMENT AT EARTH SURFACE CAUSED BY RADIO-ELECTRONIC AIDS OPERATING OVER EARTH SURFACE

    OpenAIRE

    V. I. Mordachev

    2009-01-01

    The paper provides results of modeling distribution of signal probability of radio-electronic aids located over the Earth surface at a specific height and determining an electromagnetic environment on its surface according to a power parameter and an input direction angle at an optionally selected observation point being on the earth surface.

  17. High power pulsed/microwave technologies for electron accelerators vis a vis 10MeV, 10kW electron LINAC for food irradiation at CAT

    International Nuclear Information System (INIS)

    Shrivastava, Purushottam; Mulchandani, J.; Mohania, P.; Baxy, D.; Wanmode, Y.; Hannurkar, P.R.

    2005-01-01

    Use of electron accelerators for irradiation of food items is gathering momentum in India. The various technologies for powering the electron LINAC were needed to be developed in the country due to embargo situations as well as reservations of the developers worldwide to share the information related to this development. Centre for Advanced Technology, CAT, Indore, is engaged in the development of particle accelerators for medical industrial and scientific applications. Amongst other electron accelerators developed in CAT, a 10MeV, 10kW LINAC for irradiation of food items has been commissioned and tested for full rated 10kW beam power. The high power pulsed microwave driver for the LINAC was designed, developed and commissioned with full indigenous efforts, and is right now operational at CAT. It consists of a 6MW, 25kW S-band pulsed klystron, 15MW peak power pulse modulator system for the klystron, microwave driver amplifier chain, stabilized generator, protection and control electronics, waveguide system to handle the high peak and average power, gun modulator electronics, grid electronics etc. The present paper highlights various technologies like the pulsed power systems and components, microwave circuits and systems etc. Also the performance results of the high power microwave driver for the 10MeV LINAC at CAT are discussed. Future strategies for developing the state of art technologies are highlighted. (author)

  18. K Coverage Probability of 5G Wireless Cognitive Radio Network under Shadow Fading Effects

    Directory of Open Access Journals (Sweden)

    Ankur S. Kang

    2016-09-01

    Full Text Available Land mobile communication is burdened with typical propagation constraints due to the channel characteristics in radio systems.Also,the propagation characteristics vary form place to place and also as the mobile unit moves,from time to time.Hence,the tramsmission path between transmitter and receiver varies from simple direct LOS to the one which is severely obstructed by buildings,foliage and terrain.Multipath propagation and shadow fading effects affect the signal strength of an arbitrary Transmitter-Receiver due to the rapid fluctuations in the phase and amplitude of signal which also determines the average power over an area of tens or hundreds of meters.Shadowing introduces additional fluctuations,so the received local mean power varies around the area –mean.The present section deals with the performance analysis of fifth generation wireless cognitive radio network on the basis of signal and interference level based k coverage probability under the shadow fading effects.

  19. Electron capture by He2+ ions in collisions with H and H2 at impact energies below 10 keV

    International Nuclear Information System (INIS)

    Nutt, W.L.; McCullough, R.W.; Brady, K.; Shah, M.B.; Gilbody, H.B.

    1978-01-01

    Total cross sections for the process He 2+ + H(1s) → He + (Σn, 1) + H + involving capture into all final bound states of He + have been determined for 3 He 2+ ions in the range 1.5-9.0 keV using a furnace-target technique previously employed for similar measurements at higher impact energies. Measured cross sections are considerably smaller than those measured previously by Fite et al (Proc. R.Soc.; A268:527 (1962)) and are in better accord with recent theoretical estimates. A likely explanation for the discrepancy is given in terms of the corresponding cross sections for electron capture in He 2+ -H 2 collisions which have also been determined. (author)

  20. Minimal exposure technique in the Cambridge University 600kV high resolution electron microscope

    International Nuclear Information System (INIS)

    Fryer, J.R.; Cleaver, J.R.A.; Smith, D.J.

    1980-01-01

    Radiation damage due to the incident electron beam imposes a fundamental limitation on the information obtainable by electron microscopy about organic materials; it is desirable therefore that exposure of the specimen to the electron beam should be restricted to the actual period during which the image is being recorded. A description is given of methods employed in the observation of the organic aromatic hydrocarbons quaterrylene, ovalene and coronene with the Cambridge University 600kV high resolution electron microscope (HREM). In particular, the condenser-objective mode of operation of this microscope lends itself to the use of an area-defining aperture below the second condenser lens conjugate with the specimen. Furthermore, operation at the higher accelerating voltage of this instrument could be anticipated to reduce the rate of damage, depending on the dominant beam-specimen interaction, whilst the increased width of the first broad band of the contrast transfer function of this microscope at the optimum defocus may overcome the reported resolution limitation of current 100kV microscopes for the observation of related materials. (author)

  1. Thermal and optical excitation of trapped electrons in high-density polyethylene (HDPE) studied through positron annihilation

    International Nuclear Information System (INIS)

    Nahid, F.; Zhang, J.D.; Yu, T.F.; Ling, C.C.; Fung, S.; Beling, C.D.

    2011-01-01

    Positronium (Ps) formation in high-density polyethylene (HDPE) has been studied below the glass transition temperature. The formation probability increases with positron irradiation time due to an increasing number of inter-track trapped electrons becoming available for positron capture. The temperature variation of the saturated Ps level is discussed in different models. The quenching of trapped electrons by light has been studied and the optical de-trapping cross-section for different photon energies has been estimated over the visible region.

  2. Carbon captured from the air

    International Nuclear Information System (INIS)

    Keith, D.

    2008-01-01

    This article presented an innovative way to achieve the efficient capture of atmospheric carbon. A team of scientists from the University of Calgary's Institute for Sustainable Energy, Environment and Economy have shown that it is possible to reduce carbon dioxide (CO 2 ) using a simple machine that can capture the trace amount of CO 2 present in ambient air at any place on the planet. The thermodynamics of capturing the small concentrations of CO 2 from the air is only slightly more difficult than capturing much larger concentrations of CO 2 from power plants. The research is significant because it offers a way to capture CO 2 emissions from transportation sources such as vehicles and airplanes, which represent more than half of the greenhouse gases emitted on Earth. The energy efficient and cost effective air capture technology could complement other approaches for reducing emissions from the transportation sector, such as biofuels and electric vehicles. Air capture differs from carbon capture and storage (CCS) technology used at coal-fired power plants where CO 2 is captured and pipelined for permanent storage underground. Air capture can capture the CO 2 that is present in ambient air and store it wherever it is cheapest. The team at the University of Calgary showed that CO 2 could be captured directly from the air with less than 100 kWhrs of electricity per tonne of CO 2 . A custom-built tower was able to capture the equivalent of 20 tonnes per year of CO 2 on a single square meter of scrubbing material. The team devised a way to use a chemical process from the pulp and paper industry to cut the energy cost of air capture in half. Although the technology is only in its early stage, it appears that CO 2 could be captured from the air with an energy demand comparable to that needed for CO 2 capture from conventional power plants, but costs will be higher. The simple, reliable and scalable technology offers an opportunity to build a commercial-scale plant. 1 fig

  3. Quantum ballistic transistor and low noise HEMT for cryo-electronics lower than 4.2 K

    International Nuclear Information System (INIS)

    Gremion, E.

    2008-01-01

    Next generations of cryo-detectors, widely used in physics of particles and physics of universe, will need in the future high-performance cryo-electronics less noisy and closer to the detector. Within this context, this work investigates properties of two dimensional electron gas GaAlAs/GaAs by studying two components, quantum point contact (QPC) and high electron mobility transistor (HEMT). Thanks to quantized conductance steps in QPC, we have realized a quantum ballistic transistor (voltage gain higher than 1), a new component useful for cryo-electronics thanks to its operating temperature and weak power consumption (about 1 nW). Moreover, the very low capacity of this component leads to promising performances for multiplexing low temperature bolometer dedicated to millimetric astronomy. The second study focused on HEMT with very high quality 2DEG. At 4.2 K, a voltage gain higher than 20 can be obtained with a very low power dissipation of less than 100 μW. Under the above experimental conditions, an equivalent input voltage noise of 1.2 nV/√(Hz) at 1 kHz and 0.12 nV/√(Hz) at 100 kHz has been reached. According to the Hooge formula, these noise performances are get by increasing gate capacity estimated to 60 pF. (author)

  4. Quantum probability and conceptual combination in conjunctions.

    Science.gov (United States)

    Hampton, James A

    2013-06-01

    I consider the general problem of category conjunctions in the light of Pothos & Busemeyer (P&B)'s quantum probability (QP) account of the conjunction fallacy. I argue that their account as presented cannot capture the "guppy effect" - the case in which a class is a better member of a conjunction A^B than it is of either A or B alone.

  5. Study of the mass of the electron neutrino in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Yasumi, Shinjiro; Maezawa, Hideki [eds.

    1996-02-01

    This report describes a study of the mass of the electron neutrino using electron capture in {sup 163}Ho in Japan for the period from 1981 to 1994. This monograph has two purposes, one is to supplement the papers on the mass of the electron neutrino already published by us and another is to make a record on some details of our experiments for future. Electron capture in a nucleus takes place in a rather small space inside an atom, where atomic physics, nuclear physics and particle physics work closely together. Therefore, this study needed an intimate collaboration of atomic physicists, nuclear physicists and particle physicists. In addition, it was necessary for this study to use various fine techniques, including metallurgy, production of {sup 163}Ho activity, micro-analysis by wet chemistry, isotope-dilution mass spectrometry, undulator radiation source technology, the soft X-ray monochromator technology, a counting technique for very intense soft X-rays and so on. As a result, our collaboration consisted of many researchers from various fields as follows; M. Ando, H. Arai, M. Fujioka, N. Hashimoto, H. Ikeda, Y. Inagaki, K. Ishii, K. Itoh, G. Izawa, O. Kawakami, S. Kishimoto, H. Kitamura, H. Maezawa, M. Maruyama, A. Masuda, K. Masumoto, A. Mikuni, T. Mizogawa, T. Mukoyama, F. Ochiai, T. Ohta, T. Omori, G. Rajasekaran, K. Sera, K. Shima, T. Shinozuka, P.M. Stefan, I. Sugai, H. Taketani, M. Yagi, and S. Yasumi. Without such an excellent collaboration, this study would not have been completed. We would like to express our sincere gratitude to Professor T. Sasaki for supporting this study and recommending the undulator beam line of 2.5 GeV Photon Factory Storage Ring as a light source to be used in the experiment. We also would like to thank Dr. A. Yagishita and Dr. Y. Kitajima who are responsible for the BL-2 beamline. Finally we are grateful to Ms. M. Noji for her patient typewriting of manuscripts written by hand. (author).

  6. Study of the mass of the electron neutrino in Japan

    International Nuclear Information System (INIS)

    Yasumi, Shinjiro; Maezawa, Hideki

    1996-02-01

    This report describes a study of the mass of the electron neutrino using electron capture in 163 Ho in Japan for the period from 1981 to 1994. This monograph has two purposes, one is to supplement the papers on the mass of the electron neutrino already published by us and another is to make a record on some details of our experiments for future. Electron capture in a nucleus takes place in a rather small space inside an atom, where atomic physics, nuclear physics and particle physics work closely together. Therefore, this study needed an intimate collaboration of atomic physicists, nuclear physicists and particle physicists. In addition, it was necessary for this study to use various fine techniques, including metallurgy, production of 163 Ho activity, micro-analysis by wet chemistry, isotope-dilution mass spectrometry, undulator radiation source technology, the soft X-ray monochromator technology, a counting technique for very intense soft X-rays and so on. As a result, our collaboration consisted of many researchers from various fields as follows; M. Ando, H. Arai, M. Fujioka, N. Hashimoto, H. Ikeda, Y. Inagaki, K. Ishii, K. Itoh, G. Izawa, O. Kawakami, S. Kishimoto, H. Kitamura, H. Maezawa, M. Maruyama, A. Masuda, K. Masumoto, A. Mikuni, T. Mizogawa, T. Mukoyama, F. Ochiai, T. Ohta, T. Omori, G. Rajasekaran, K. Sera, K. Shima, T. Shinozuka, P.M. Stefan, I. Sugai, H. Taketani, M. Yagi, and S. Yasumi. Without such an excellent collaboration, this study would not have been completed. We would like to express our sincere gratitude to Professor T. Sasaki for supporting this study and recommending the undulator beam line of 2.5 GeV Photon Factory Storage Ring as a light source to be used in the experiment. We also would like to thank Dr. A. Yagishita and Dr. Y. Kitajima who are responsible for the BL-2 beamline. Finally we are grateful to Ms. M. Noji for her patient typewriting of manuscripts written by hand. (author)

  7. PROBABLE CHARACTERISTICS ОF ELECTROMAGNETIC FIELD ENVIRONMENT AT EARTH SURFACE CAUSED BY RADIO-ELECTRONIC AIDS OPERATING OVER EARTH SURFACE

    Directory of Open Access Journals (Sweden)

    V. I. Mordachev

    2009-01-01

    Full Text Available The paper provides results of modeling distribution of signal probability of radio-electronic aids located over the Earth surface at a specific height and determining an electromagnetic environment on its surface according to a power parameter and an input direction angle at an optionally selected observation point being on the earth surface.

  8. Low frequency internal friction behaviour of copper after electron-irradiation at 20 K

    International Nuclear Information System (INIS)

    Sokolowski, G.; Kabsch, Z.; Moser, P.

    1978-01-01

    High-purity ASARCO-copper has been irradiated with 3MeV-electrons at 20 K. Then the temperature dependence of modulus and decrement has been measured at 2 Hz and a strain amplitude of 10 -5 . The dislocation pinning in stage I can be seen in modulus and decrement. It is followed by a depinning process in the modulus between 130 and 190 K. This depinning corresponds to the temperature where the decrement begins to increase again after stage I-pinning. The effects are discussed and compared to 78K irradiations using the same sample material and similar pre-treatment

  9. Capture from pair production as a beam loss mechanism for heavy ions at RHIC

    International Nuclear Information System (INIS)

    Feinberg, B.; Belkacem, A.; Claytor, N.; Dinneen, T.; Gould, H.

    1997-05-01

    Electron capture from electron-positron pair production is predicted to be a major source of beam loss for the heaviest ions at RHIC. Achieving the highest luminosity thus requires an understanding of the capture process. The authors report measurements of this process at Brookhaven National Laboratory's AGS using 10.8 GeV/nucleon Au 79+ projectiles on Au targets. Capture from pair production is a process in which the very high electromagnetic field involved in the collision of two relativistic heavy ions results in the production of an electron-positron pair with the capture of the electron by one of the ions. There are many theoretical papers published on capture from pair production with discrepancies between predicted cross sections. The experimental results are compared to theory and to previous experiments at 1 GeV/nucleon. The implications of extrapolations to RHIC energies are presented

  10. The influence of the electron wave function on the Pt Lsub(I) and Lsub(III) ionization probabilities by 3.6 MeV He impact

    International Nuclear Information System (INIS)

    Ullrich, J.; Dangendorf, V.; Dexheimer, K.; Do, K.; Kelbch, C.; Kelbch, S.; Schadt, W.; Schmidt-Boecking, H.; Stiebing, K.E.; Roesel, F.; Trautmann, D.

    1986-01-01

    For 3.6 MeV He impact the Lsub(I) and Lsub(III) subshell ionization probabilities of Pt have been measured. Due to relativistic effects in the electron wave functions, the Lsub(I) subshell ionization probability Isub(LI)(b) is strong enhanced at small impact parameters exceeding even Isub(LIII)(b) in nice agreement with the SCA theory. (orig.)

  11. CAPTURE OF TROJANS BY JUMPING JUPITER

    International Nuclear Information System (INIS)

    Nesvorný, David; Vokrouhlický, David; Morbidelli, Alessandro

    2013-01-01

    Jupiter Trojans are thought to be survivors of a much larger population of planetesimals that existed in the planetary region when planets formed. They can provide important constraints on the mass and properties of the planetesimal disk, and its dispersal during planet migration. Here, we tested a possibility that the Trojans were captured during the early dynamical instability among the outer planets (aka the Nice model), when the semimajor axis of Jupiter was changing as a result of scattering encounters with an ice giant. The capture occurs in this model when Jupiter's orbit and its Lagrange points become radially displaced in a scattering event and fall into a region populated by planetesimals (that previously evolved from their natal transplanetary disk to ∼5 AU during the instability). Our numerical simulations of the new capture model, hereafter jump capture, satisfactorily reproduce the orbital distribution of the Trojans and their total mass. The jump capture is potentially capable of explaining the observed asymmetry in the number of leading and trailing Trojans. We find that the capture probability is (6-8) × 10 –7 for each particle in the original transplanetary disk, implying that the disk contained (3-4) × 10 7 planetesimals with absolute magnitude H disk ∼ 14-28 M Earth , is consistent with the mass deduced from recent dynamical simulations of the planetary instability.

  12. Dose due to 40K

    International Nuclear Information System (INIS)

    Escareno J, E.; Vega C, H. R.

    2011-10-01

    The dose due to 40 K has been estimated. Potassium is one of the most abundant elements in nature, being approximately 2% of the Earth's crust. Potassium has three isotopes 39 K, 40 K and 41 K, two are stable while 40 K is radioactive with a half life of 1.2x10 9 years; there is 0.0117% 40 K-to-K ratio. Potassium plays an important role in plants, animals and humans growth and reproduction. Due to the fact that K is an essential element for humans, 40 K is the most abundant radioisotope in human body. In order to keep good health conditions K must be intake at daily basis trough food and beverages, however when K in ingested above the requirements produce adverse health effects in persons with renal, cardiac and hypertension problems or suffering diabetes. In 89.3% 40 K decays to 40 C through β-decay, in 10.3% decays through electronic capture and emitting 1.46 MeV γ-ray. K is abundant in soil, construction materials, sand thus γ-rays produced during 40 K decay contribute to external dose. For K in the body practically all 40 K decaying energy is absorbed by the body; thus 40 K contributes to total dose in humans and it is important to evaluate its contribution. In this work a set of 40 K sources were prepared using different amounts of KCl salt, a γ-ray spectrometer with a NaI(Tl) was characterized to standardized the sources in order to evaluate the dose due to 40 K. Using thermoluminescent dosemeters the dose due to 40 K was measured and related to the amount of 40 K γ-ray activity. (Author)

  13. Radiative electron rearrangement and polarization in target K x-ray spectra

    International Nuclear Information System (INIS)

    Jamison, K.A.

    1978-01-01

    Two topics in the atomic physics of ion-atom collisions are studied. The first is an investigation of a free-atom decay process that is shown to be a two-electron one-photon decay. This two-electron decay requires an initial state with multiple inner-shell vacancies that has a high probability of creation in ion-atom collisions. Because this decay promotes one electron to a higher shell while allowing the other to fall to a lower shell, it is referred to as radiative electron rearrangement (RER). The investigation of this process includes the experimental study of the x-ray spectra region approx. 150 eV below the characteristic Kα 1 2 target radiation in third period elements when bombarded by various ion beams in the energy range 1 to 2 MeV/amu. Theoretical calculations of the transition energies, line strengths, and line widths are performed to verify the origin of the RER lines. The second topic of consideration is the study of the polarization of Kα satellite radiation from targets of Al and Si. It is shown that the polarization, which is observed experimentally with a curved-crystal polarimeter, is due to the nonstatistical population of the magnetic substates created in specific ion-atom collisions. Further, the polarization of the RER lines is studied. The connection between the polarization of the normal Kα satellite radiation and the polarization of the RER lines adds final proof to their origin as two-electron one-photon transitions

  14. Intravenous coronary angiography utilizing K-emission and bremsstrahlung X-rays produced by electron bombardment

    International Nuclear Information System (INIS)

    1992-01-01

    The screening of the general population for coronary artery disease would be practical if a method existed for visualizing the extent of occlusion after an intravenous injection of contrast agent. Measurements performed with synchrotron radiation at SSRL and NSLS have shown that such an intravenous angiography procedure would be possible with an intense source of monochromatic X-rays. Because of the high cost of an electron synchrotron, theoretical analysis and experiments using inanimate phantoms has been undertaken to demonstrate the feasibility of using the spectrum produced by two appropriately chosen anode materials when bombarded with electrons in the 100--500 keV energy range for angiography. By using the X-rays emitted at 120 degree to the incident electron direction, about 20--30% of the X-ray intensity would be due to K-emission lines. Calculations using the TIGERP Monte Carlo Code, have shown that high quality angiograms of human coronary arteries should be possible with a contrast agent containing ytterbium, if an electron beam pulses of 16 kJ were used for each anode target. The experimental program supported in part by the DOE has consisted of these theoretical calculations and experiments at the Dynamitron Electron Accelerator Facility at BNL

  15. Absolute disintegration rate and 320 keV {gamma}-ray emission probability of {sup 51}Cr

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, M.C.M. de [Laboratorio Nacional de Metrologia das Radiacoes Ionizantes /Instituto de Radioprotecao e Dosimetria (LNMRI/ IRD), Avenida Salvador Allende, s/no. Recreio-Rio de Janeiro, CEP 22780-160 (Brazil)], E-mail: candida@ird.gov.br; Iwahara, A.; Poledna, R.; Silva, C.J. da; Delgado, J.U. [Laboratorio Nacional de Metrologia das Radiacoes Ionizantes /Instituto de Radioprotecao e Dosimetria (LNMRI/ IRD), Avenida Salvador Allende, s/no. Recreio-Rio de Janeiro, CEP 22780-160 (Brazil)

    2007-09-21

    This work describes the procedures for determining absolutely the {sup 51}Cr disintegration rate by using the 4{pi}{beta}-{gamma} coincidence and anti-coincidence counting and the sum-peak methods. A 4''x4''-NaI(Tl) scintillation detector was used in the {gamma}- channel of the 4{pi}{beta}-{gamma} coincidence system for {gamma}-ray counting. In the {beta}-channel, a 4{pi} gas flow proportional counter was used for counting of characteristic X-rays and Auger electrons originating from the electron capture events of the {sup 51}Cr decay scheme. Gamma spectrometry measurements by high-pure planar and coaxial germanium detectors were performed in the sum-peak method and in the determination of the 320 keV {gamma}-emission probability of {sup 51}Cr. This latter determined value agrees with the recent values found in the literature, confirming the reliability of the three methods used in this work for the disintegration rate measurements.

  16. Spin-polarized electron capture for the Na+3He2+ system at a 3He2+ impact energy of 5.33--9.33 keV/amu

    International Nuclear Information System (INIS)

    Tanaka, M.; Shimakura, N.; Ohshima, T.; Katori, K.; Fujiwara, M.; Ogata, H.; Kondo, M.

    1994-01-01

    3 He + atomic polarizations following the spin-polarized electron capture process for the N rvec a(3s)+ 3 He 2+ system were measured at 3 He 2+ impact energies from 5.33 to 9.33 keV/amu. The magnitude of the 3 He + atomic polarizations was deduced from the 3 He + nuclear polarization measured by means of beam-foil spectroscopy. The observed polarization transfer coefficient P T defined by the ratio of the 3 He + atomic polarization to the sodium one showed a pronounced reduction from unity, which was qualitatively explained by the prediction of a simple cascade photon decay model. Evidence for a further reduction of P T from the above model and a possible impact energy dependence of P T suggested an excessive depolarization due to the presence of the collision alignment parameter A 0 col of 3 He + formed by the electron capture process. In order to see this more closely, the observed P T 's were examined theoretically using the semiclassical impact parameter method, in which an 18-state molecular expansion was employed, and atomic-type electron translation effects were rigorously taken into account. Ensuring that both the absolute values and the impact energy dependence of the observed capture cross sections were remarkably well reproduced by the calculations in which the states up to 4f in 3 He + were introduced, it was demonstrated that the calculated results for P T qualitatively reproduced not only the absolute values of the observed P T 's but also their gentle decrease with increasing impact energy. Production of nuclear polarizations resulting from the polarized electron capture processes between multicharged heavy ions and alkaline-earth-metal atoms is an example of one use of the future project of universal polarized heavy-ion sources

  17. Exploratory investigations of hypervelocity intact capture spectroscopy

    Science.gov (United States)

    Tsou, P.; Griffiths, D. J.

    1993-01-01

    The ability to capture hypervelocity projectiles intact opens a new technique available for hypervelocity research. A determination of the reactions taking place between the projectile and the capture medium during the process of intact capture is extremely important to an understanding of the intact capture phenomenon, to improving the capture technique, and to developing a theory describing the phenomenon. The intact capture of hypervelocity projectiles by underdense media generates spectra, characteristic of the material species of projectile and capture medium involved. Initial exploratory results into real-time characterization of hypervelocity intact capture techniques by spectroscopy include ultra-violet and visible spectra obtained by use of reflecting gratings, transmitting gratings, and prisms, and recorded by photographic and electronic means. Spectrometry proved to be a valuable real-time diagnostic tool for hypervelocity intact capture events, offering understanding of the interactions of the projectile and the capture medium during the initial period and providing information not obtainable by other characterizations. Preliminary results and analyses of spectra produced by the intact capture of hypervelocity aluminum spheres in polyethylene (PE), polystyrene (PS), and polyurethane (PU) foams are presented. Included are tentative emission species identifications, as well as gray body temperatures produced in the intact capture process.

  18. Water Capture Device Signal Integration Board

    Science.gov (United States)

    Chamberlin, Kathryn J.; Hartnett, Andrew J.

    2018-01-01

    I am a junior in electrical engineering at Arizona State University, and this is my second internship at Johnson Space Center. I am an intern in the Command and Data Handling Branch of Avionics Division (EV2), my previous internship was also in EV2. During my previous internship I was assigned to the Water Capture Device payload, where I designed a prototype circuit board for the electronics system of the payload. For this internship, I have come back to the Water Capture Device project to further the work on the electronics design I completed previously. The Water Capture Device is an experimental payload to test the functionality of two different phase separators aboard the International Space Station (ISS). A phase separator sits downstream of a condensing heat exchanger (CHX) and separates the water from the air particles for environmental control on the ISS. With changing CHX technology, new phase separators are required. The goal of the project is to develop a test bed for the two phase separators to determine the best solution.

  19. Study of K, L vacancies production mechanisms by X spectrometry in the interaction induced by a few MeV/A charged particles

    International Nuclear Information System (INIS)

    Andriamonje, S.

    1982-01-01

    The analysis of different mechanisms producing electronic inner shell vacancies in ion atom collisions at a few MeV/A charged is presented. The mutual influence of nuclear and atomic excitation in the ionization probability has been discussed. The 106 Cd(p,p') 106 Cd reaction (Ep=10 MeV) has been particularly investigated from this point. The investigation is followed up by the description of the theoretical and experimental methods which permit the determination of the total and/or differential X rays production cross section for different interaction. The gold sub-shell L 1 , L 2 , L 3 ionization probability has been studied in the Au(H + ,H + )Au reaction at Ep=1 MeV. In the second part of the manuscript we investigate in detail the influence of the charge exchange process on inner shell vacancy production. The N 2 , Ar, Kr targets have been produced by a system jet gas and bombarded by 0.8 28 Si 14+ ions at E=125 MeV. The cross section for the capture of an electron in K shell, L shell and total charge exchange have been measured and compared to the CDW theory (Continuum Distorted Wave). In the CDW validity domain the experimental and theoretical results are a good agreement. In the collisions induced by H + , ionization is found to be the main excitation process. On the contrary, in collisions induced by 28 Si 14+ charge exchange is dominant compared to ionization [fr

  20. Spectral study of the electron beam emitted from a 3 kJ plasma focus

    International Nuclear Information System (INIS)

    Patran, A; Tan, L C; Stoenescu, D; Rafique, M S; Rawat, R S; Springham, S V; Tan, T L; Lee, P; Zakaullah, M; Lee, S

    2005-01-01

    In a 3 kJ Mather-type plasma focus device operated in neon, the electron beam emission is investigated using both a magnetic electron energy analyser (in the 30-660 keV range) and a Rogowski coil (coupled with an appropriate RC passive integrator). Several electron emission features are identified and correlated with the x-ray emission in different energy ranges. The electron beam output shows very strong correlation with the general plasma dynamics (breakdown, axial and radial acceleration, pinch and post-pinch phases). The electrons' energy spectra showed most of the electron emission concentrating below 200 keV and negligible emission with energy above 350 keV. At 4 mbar neon, the electron emission, as well as the beam energy, is the highest and has a good shot-to-shot reproducibility