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Sample records for neutron deficient te

  1. Deformation and shape transitions in hot rotating neutron deficient Te isotopes

    International Nuclear Information System (INIS)

    Aggarwal, Mamta; Mazumdar, I.

    2009-01-01

    Evolution of the nuclear shapes and deformations under the influence of temperature and rotation is investigated in Te isotopes with neutron number ranging from the proton drip line to the stability valley. Spin dependent critical temperatures for the shape transitions in Te nuclei are computed. Shape transitions from prolate at low temperature and spin to oblate via triaxiality are seen with increasing neutron number and spin.

  2. Study of neutron-deficient Sn isotopes

    International Nuclear Information System (INIS)

    Auger, G.

    1982-05-01

    The formation of neutron deficient nuclei by heavy ion reactions is investigated. The experimental technique is presented, and the results obtained concerning Sn et In isotopes reported: first excited states of 106 Sn, high spin states in 107 Sn and 107 In; Yrast levels of 106 Sn, 107 Sn, 108 Sn; study of neutron deficient Sn and In isotopes formed by the desintegration of the compound nucleus 112 Xe. All these results are discussed [fr

  3. Fast Neutron Detection Using Pixelated CdZnTe Spectrometers

    Science.gov (United States)

    Streicher, Michael; Goodman, David; Zhu, Yuefeng; Brown, Steven; Kiff, Scott; He, Zhong

    2017-07-01

    Fast neutrons are an important signature of special nuclear materials (SNMs). They have a low natural background rate and readily penetrate high atomic number materials that easily shield gamma-ray signatures. Therefore, they provide a complementary signal to gamma rays for detecting shielded SNM. Scattering kinematics dictate that a large nucleus (such as Cd or Te) will recoil with small kinetic energy after an elastic collision with a fast neutron. Charge carrier recombination and quenching further reduce the recorded energy deposited. Thus, the energy threshold of CdZnTe detectors must be very low in order to sense the small signals from these recoils. In this paper, the threshold was reduced to less than 5 keVee to demonstrate that the 5.9-keV X-ray line from 55Fe could be separated from electronic noise. Elastic scattering neutron interactions were observed as small energy depositions (less than 20 keVee) using digitally sampled pulse waveforms from pixelated CdZnTe detectors. Characteristic gamma-ray lines from inelastic neutron scattering were also observed.

  4. Laser Spectroscopy Study on the Neutron-Rich and Neutron-Deficient Te Isotopes

    CERN Multimedia

    2002-01-01

    We propose to perform laser spectroscopy measurements on the Te isotopes. This will give access to fundamental properties of the ground and rather long-lived isomeric states such as the change in the mean square charge radius ($\\delta\\langle$r$^2_c\\rangle$) and the nuclear moments. For these medium-mass isotopes, at this moment the optical resolution obtained with RILIS is not high enough to perform isotope shift measurements. Thus we will use the COMPLIS experimental setup which allows Resonant Ionization Spectroscopy (RIS) on laser desorbed atoms. The 5p$^{4}$ $^{3}$P$_{2} \\rightarrow$ 5p$^{3}$ 6s $^{3}$S$_{1}$ and 5p$^{4}$ $^{3}$P$_{2} \\rightarrow$ 5p$^{3}$ 6s $^{5}$S$_{2}$ optical transitions have been used to perform, on the stable Te isotopes, the tests required by the INTC committee. For this purpose stable-ion sources have been built and Te isotopes have been delivered as stable beams by the injector coupled to the COMPLIS setup. ISOLDE offers the opportunity for studying the Te isotope series over a ...

  5. Alpha decay of neutron-deficient isotopes with 52Te (T/sub 1/2/=60 mu s) and /sup 110/Xe

    CERN Document Server

    Schardt, D; Kirchner, R; Klepper, O; Kurcewicz, W; Roeckl, E; Tidemand-Petersson, P

    1981-01-01

    Using /sup 58/Ni(/sup 58/Ni, xpyn) reactions and on-line mass separation, the alpha -decays of very neutron-deficient isotopes of tellurium, iodine, xenon and cesium were studied. The new isotopes /sup 106/Te (T/sub 1/2/=60/sub -10//sup +30/ mu s) and /sup 110/Xe were identified by their alpha -lines of 4160+or-30 keV and 3737+or-30 keV energy, respectively, with the genetic relationship between the two successive alpha -decays being verified experimentally, while for several other alpha -decaying isotopes more precise data were obtained. The observed alpha -decay properties are discussed within the systematics of energy and reduced width. (19 refs).

  6. Yrast spectroscopy in the neutron-deficient nucleus 169Os

    International Nuclear Information System (INIS)

    Joss, D.T.; Simpson, J.; Appelbe, D.E.; Warner, D.D.; Page, R.D.; King, S.L.; Amzal, N.; Cullen, D.M.; Greenlees, P.T.; Keenan, A.; Baeck, T.; Cederwall, B.; Wyss, R.; Bentley, M.A.; Williams, S.J.; Cocks, J.F.C.; Helariutta, K.; Jones, P.M.; Julin, R.; Juutinen, S.

    2002-01-01

    Excited states in the neutron-deficient isotope 169 Os have been identified for the first time in an experiment using the Jurosphere γ-ray spectrometer in conjunction with the Ritu gas-filled recoil separator. The problems associated with identifying neutron-deficient isotopes produced with low fusion cross sections against a high background of competing channels, including fission, have been overcome by using the recoil-decay tagging technique. The band structures observed in 169 Os are interpreted in the context of the systematics of neighboring nuclei and the predictions of cranked Woods-Saxon calculations. The systematics of the second (i 13/2 ) 2 neutron alignment in this region are discussed

  7. Spectroscopy of very neutron-deficient hafnium and tungsten isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Dracoulis, G D; Fabricius, B; Davidson, P M [Australian National Univ., Canberra, ACT (Australia). Dept. of Nuclear Physics; Macchiavelli, A O; Oliviera, J; Burde, J; Stephens, F; Deleplanque, M A [Lawrence Berkeley Lab., CA (United States)

    1992-08-01

    Level schemes of the very neutron-deficient isotopes {sup 158}Hf and {sup 162}W have been identified, and that for {sup 164}W extended. Alignment of the H{sub 9/2} neutrons is suggested. (author). 12 refs., 7 figs.

  8. Study of Neutron-Deficient $^{202-205}$Fr Isotopes with Collinear Resonance Ionization Spectroscopy

    CERN Document Server

    De Schepper, Stijn; Cocolios, Thomas; Budincevic, Ivan

    The scope of this master’s thesis is the study of neutron-deficient $^{202−205}$Fr isotopes. These isotopes are inside the neutron-deficient lead region, a region that has shown evidence of shape coexistence. For this thesis, this discussion is limited to the phenomenon where a low lying excited state has a different shape than the ground state. Shape coexistence is caused by intruder states. These are single-particle Shell Model states that are perturbed in energy due to the interaction with a deformed core. In the neutron-deficient lead region the main proton intruder orbit is the 3s$_{1/2}$orbit. When going towards more neutron-deficient isotopes, deformation increases. The $\\pi3s_{1/2}$orbit will rise in energy and will eventually become the ground state in odd- A bismuth (Z=83) isotopes. It is also observed in odd-A astatine (Z=85) isotopes, already in less neutron-deficient nuclei. The same phenomenon is expected to be present francium (Z=87) isotopes already at $^{199}$Fr. Although it is currently ...

  9. Towards 100Sn: Studies on neutron-deficient even isotopes of tin

    International Nuclear Information System (INIS)

    Rathke, G.E.

    1987-02-01

    Neutron-deficient 108,106,104 Sn isotopes were produced by heavy ion induced fusion reactions using high-intensity 59 Ni beams from the UNILAC of the GSI. Their decay properties were studied by techniques of gamma and conversion electron spectroscopy employing the mass separator on-line to the UNILAC. Earlier information on the 108 Sn → 108 In and 106 Sn → 106 In decays was complemented and improved in the course of this work. The new nucleus 104 Sn and its decay to excited states in 104 In was identified and studied for the first time. These investigations yield the following results: the mass of 104 Sn and of nuclei linked to it by alpha decay or proton radioactivity, 108 Te, 112 Xe and 109 I, 113 Cs, respectively were determined from the measured Q EC value of 104 Sn and the known mass value of 104 In. These are nuclei very close or beyond the proton drip line. In addition, information on the quenching of the fast Gamow-Teller beta decay of the even neutron-deficient tin isotopes was obtained. This complements investigations on the N = 50 isotones 94 Ru and 96 Pd, and allows a systematic comparison of these transition strengths for nuclei near the doubly magic 100 Sn. The spreading of the vertical strokeπg 9/2 -1 vg 7/2 , 1 + > configuration over several states, due to residual interactions, and the centroid energies of these magnetic dipole states were determined for the corresponding odd-odd indium isotopes. (orig./HSI)

  10. Deficiency in Monte Carlo simulations of coupled neutron-gamma-ray fields

    NARCIS (Netherlands)

    Maleka, Peane P.; Maucec, Marko; de Meijer, Robert J.

    2011-01-01

    The deficiency in Monte Carlo simulations of coupled neutron-gamma-ray field was investigated by benchmarking two simulation codes with experimental data. Simulations showed better correspondence with the experimental data for gamma-ray transport only. In simulations, the neutron interactions with

  11. Symmetry structure in neutron deficient xenon nuclei

    International Nuclear Information System (INIS)

    Govil, I. M.

    1998-01-01

    The paper describes the measurements of the lifetimes of the excited states in the ground state band of the Neutron deficient Xe nuclei ( 122,124 Xe) by recoil Distance Method (RDM). The lifetimes of the 2 + state in 122 Xe agrees with the RDM measurements but for 124 Xe it does not agree the RDM measurements but agrees with the earlier Coulomb-excitation experiment. The experimental results are compared with the existing theories to understand the changes in the symmetry structure of the Xe-nuclei as the Neutron number decreases from N=76( 130 Xe) to N=64( 118 Xe)

  12. Symmetry structure in neutron deficient xenon nuclei

    Science.gov (United States)

    Govil, I. M.

    1998-12-01

    The paper describes the measurements of the lifetimes of the excited states in the ground state band of the Neutron deficient Xe nuclei (122,124Xe) by recoil Distance Method (RDM). The lifetimes of the 2+ state in 122Xe agrees with the RDM measurements but for 124Xe it does not agree the RDM measurements but agrees with the earlier Coulomb-excitation experiment. The experimental results are compared with the existing theories to understand the changes in the symmetry structure of the Xe-nuclei as the Neutron number decreases from N=76(130Xe) to N=64(118Xe).

  13. Evaluation of CdZnTe as neutron detector around medical accelerators

    International Nuclear Information System (INIS)

    Martin-Martin, A.; Iniguez, M. P.; Luke, P. N.; Barquero, R.; Lorente, A.; Morchon, J.; Gallego, E.; Quincoces, G.; Marti-Climent, J. M.

    2009-01-01

    The operation of electron linear accelerators (LINACs) and cyclotrons can produce a mixed gamma-neutron field composed of energetic neutrons coming directly from the source and scattered lower energy neutrons. The thermal neutron detection properties of a non-moderated coplanar-grid CdZnTe (CZT) gamma-ray detector close to an 18 MV electron LINAC and an 18 MeV proton cyclotron producing the radioisotope 18 F for positron emission tomography are investigated. The two accelerators are operated at conditions producing similar thermal neutron fluence rates of the order of 104 cm -2 s -1 at the measurement locations. The counting efficiency of the CZT detector using the prompt 558 keV photopeak following 113 Cd thermal neutron capture is evaluated and a good neutron detection performance is found at the two installations. (authors)

  14. Study of asymmetric fission yield behavior from neutron-deficient Hg isotope

    International Nuclear Information System (INIS)

    Perkasa, Y. S.; Waris, A.; Kurniadi, R.; Su'ud, Z.

    2014-01-01

    A study of asymmetric fission yield behavior from a neutron-deficient Hg isotope has been conducted. The fission yield calculation of the neutron-deficient Hg isotope using Brownian Metropolis shape had showed unusual result at decreasing energy. In this paper, this interesting feature will be validated by using nine degree of scission shapes parameterization from Brosa model that had been implemented in TALYS nuclear reaction code. This validation is intended to show agreement between both model and the experiment result. The expected result from these models considered to be different due to dynamical properties that implemented in both models

  15. Thin film CdTe based neutron detectors with high thermal neutron efficiency and gamma rejection for security applications

    Energy Technology Data Exchange (ETDEWEB)

    Smith, L.; Murphy, J.W. [Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Kim, J. [Korean Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of); Rozhdestvenskyy, S.; Mejia, I. [Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Park, H. [Korean Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of); Allee, D.R. [Flexible Display Center, Arizona State University, Phoenix, AZ 85284 (United States); Quevedo-Lopez, M. [Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Gnade, B., E-mail: beg031000@utdallas.edu [Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States)

    2016-12-01

    Solid-state neutron detectors offer an alternative to {sup 3}He based detectors, but suffer from limited neutron efficiencies that make their use in security applications impractical. Solid-state neutron detectors based on single crystal silicon also have relatively high gamma-ray efficiencies that lead to false positives. Thin film polycrystalline CdTe based detectors require less complex processing with significantly lower gamma-ray efficiencies. Advanced geometries can also be implemented to achieve high thermal neutron efficiencies competitive with silicon based technology. This study evaluates these strategies by simulation and experimentation and demonstrates an approach to achieve >10% intrinsic efficiency with <10{sup −6} gamma-ray efficiency.

  16. A Neutron Scattering Study of Lattice Dynamics of HgTe and HgSe

    DEFF Research Database (Denmark)

    Kepa, H.; Giebultowicz, T.; Buras, B.

    1982-01-01

    The dispersion relations for the acoustic and optic phonons in HgTe and for the acoustic phonons in HgSe were determined by neutron inelastic scattering in three high symmetry directions. The effect of the free-carrier screening of the long-range electric field of LO phonons in HgTe was observed....... The formalism of the rigid ion model is used for numerical calculations of the phonon dispersion relations and the phonon densities of states in HgTe and HgSe....

  17. Compensation scheme for online neutron detection using a Gd-covered CdZnTe sensor

    Energy Technology Data Exchange (ETDEWEB)

    Dumazert, Jonathan, E-mail: jonathan.dumazert@cea.fr; Coulon, Romain; Kondrasovs, Vladimir; Boudergui, Karim

    2017-06-11

    The development of portable and personal neutron dosimeters requires compact and efficient radiation sensors. Gd-157, Gd-155 and Cd-113 nuclei present the highest cross-sections for thermal neutron capture among natural isotopes. In order to allow for the exploitation of the low and medium-energy radiative signature of the said captures, the contribution of gamma background radiation, falling into the same energy range, needs to be cancelled out. This paper introduces a thermal neutron detector based on a twin-dense semiconductor scheme. The neutron-sensitive channel takes the form of a Gd-covered CdZnTe crystal, a high density and effective atomic number detection medium. The background compensation will be carried out by means of an identical CdZnTe sensor with a Tb cover. The setting of a hypothesis test aims at discriminating the signal generated by the signature of thermal neutron captures in Gd from statistical fluctuations over the compensation of both independent channels. The measurement campaign conducted with an integrated single-channel chain and two metal Gd and Tb covers, under Cs-137 and Cf-252 irradiations, provides first quantitative results on gamma-rejection and neutron sensitivity. The described study of concept gives grounds for a portable, online-compatible device, operable in conventional to controlled environments.

  18. Skin Dose Equivalent Measurement from Neutron-Deficient Isotopes

    International Nuclear Information System (INIS)

    Hsu, Hsiao-Hua; Costigan, Steve A.; Romero, Leonard L.; Whicker, Jeffrey J.

    1997-12-01

    Neutron-deficient-isotopes decay via positron emission and/or electron capture often followed by x-ray, gamma-ray, and 0.511 MeV photons from positron annihilation. For cases of significant area and/or personnel contamination with these isotopes, determination of skin dose equivalent (SDE) is required by 10CFR835. For assessment of SDE, we evaluated the MICROSPEC-2(TM) system manufactured by Bubble Technology Industries of Canada which uses three different probes for dose measurement. We used two probes: (1) the X-probe which measures lower energy (4 - 120 keV) photon energy distributions and determines deep dose equivalent, SDE and dose equivalent to eyes, and (2) the B-probe which measures electron (positron) energy distributions, and determines skin dose equivalent. Also, the measured photon and beta spectra can be used to identify radioactive isotopes in the contaminated area. Measurements with several neutron-deficient sources showed that this system provided reasonably accurate SDE rate measurements when compared with calculated benchmark SDE rates with an average percent difference of 40%. Variations were expected because of differences between the assumed geometries used by MlCROSPEC-2 and the calculations when compared to the measurement conditions

  19. Fluorescent atom coincidence spectroscopy of extremely neutron-deficient barium isotopes

    International Nuclear Information System (INIS)

    Wells, S.A.; Evans, D.E.; Griffith, J.A.R.; Eastham, D.A.; Groves, J.; Smith, J.R.H.; Tolfree, D.W.L.; Warner, D.D.; Billowes, J.; Grant, I.S.; Walker, P.M.

    1988-01-01

    Fluorescent atom coincidence spectroscopy (FACS) has been used to measure the nuclear mean square radii and moments of the extremely neutron-deficient isotopes 120-124 Ba. At N=65 an abrupt change in nuclear mean square charge radii is observed which can be understood in terms of the occupation of the spin-orbit partner g 7/2 5/2[413] neutron and g 9/2 9/2[404] proton orbitals and the consequent enhancement of the n-p interaction. (orig.)

  20. Structural studies of WO3-TeO2 glasses by high-Q-neutron diffraction and Raman spectroscopy

    International Nuclear Information System (INIS)

    Khanna, A.; Kaur, A.; Krishna, P.S.R.; Shinde, A.B.

    2013-01-01

    Glasses from the system: xWO 3 -(100-x)TeO 2 (x=15, 20 and 25 mol %) were prepared by melt quenching technique and characterized by density, UV-visible absorption spectroscopy, Differential Scanning Calorimetry (DSC), Raman spectroscopy and high-Q neutron diffraction measurements. Glass density and glass transition temperature increased with increase in WO 3 concentration, Raman spectroscopy indicated the conversion of TeO 4 units into TeO 3 units with increase in WO 3 content. The increase in glass transition temperature with the incorporation of WO 3 was attributed to the increase in average bond strength of the glass network since the bond dissociation energy of W-O bonds (672 kJ/mol) is significantly higher than that of Te-O bonds (376 kJ/mol). UV-visible studies found a very strong optical absorption band due to W 6+ ions, just below the absorption edge. High-Q neutron diffraction measurements were performed on glasses and radial distribution function analyses revealed changes in W-O and Te-O correlations in the glass network. The findings about changes in glass structure from neutron diffraction studies were consistent with structural information obtained from Raman spectroscopy and structure-property correlations were made. (author)

  1. Charge radii of neutron-deficient Ca isotopes

    Science.gov (United States)

    Miller, A. J.; Minamisono, K.; Klose, A.; Everett, N.; Kalman, C.; Powel, R. C.; Watkins, J.; Garand, D.; Sumithrarachchi, C.; Krämer, J.; Maa, B.; Nörtershäuser, W.; Rossi, D. M.; Kujawa, C.; Pineda, S.; Lantis, J.; Liu, Y.; Mantica, P. F.; Pearson, M. R.

    2017-09-01

    Nucleon shell closures are generally associated with a local minimum in mean-square charge radii, 〈r2 〉 , along an isotopic chain. The 〈r2 〉 of 18Ar and 19K isotopes, however, do not show this signature at the N = 20 neutron shell closure. To gain a microscopic understanding of this abnormal behavior, measurements of 〈r2 〉 of neutron-deficient Ca isotopes below N = 20 have been proposed at the BEam COoling and LAser spectroscopy (BECOLA) facility at NSCL/MSU. Preliminary results will be presented and the deduced charge radii will be compared to theoretical calculations and the trends in the nearby isotopic chains. Work supported in part by NSF Grant PHY-15-65546, U.S. DOE Grant DE-NA0002924 and by the Deutsche Forschungsgemeinschaft through Grant SFB 1245.

  2. Laser-assisted decay and optical spectroscopy studies of neutron-deficient thallium isotopes

    CERN Document Server

    Van Beveren, Céline; Huyse, Mark

    The neutron-deficient thallium isotopes with one proton less than the Z = 82 shell closure, are situated in an interesting region of the nuclear chart, notorious for intruder states and shape coexistence. Shape coexistence is the remarkable phenomenon in which two or more distinct types of deformation occur at low energy in the same atomic nucleus. Shape coexistence has been studied intensively, experimentally as well as theoretically in different nuclei in the light-lead region and the isomerism in the thallium isotopes was among the first indications of this phenomenon. Different shapes, whose structure has been linked to specific proton orbitals above and below the Z = 82 shell closure, are present at low energy in the neutron-deficient odd-mass thallium nuclei. In the odd-odd nuclei, the coupling of an unpaired proton and unpaired neutron gives rise to multiplets of low-lying states from which some can be isomeric. Since thallium has one proton missing in the major proton shell, and when approaching neutr...

  3. Radiochemical studies of neutron deficient actinide isotopes

    International Nuclear Information System (INIS)

    Williams, K.E.

    1978-04-01

    The production of neutron deficient actinide isotopes in heavy ion reactions was studied using alpha, gamma, x-ray, and spontaneous fission detection systems. A new isotope of berkelium, 242 Bk, was produced with a cross-section of approximately 10 μb in reactions of boron on uranium and nitrogen on thorium. It decays by electron capture with a half-life of 7.0 +- 1.3 minutes. The alpha-branching ratio for this isotope is less than 1% and the spontaneous fission ratio is less than 0.03%. Studies of (Heavy Ion, pxn) and (Heavy Ion, αxn) transfer reactions in comparison with (Heavy ion, xn) compound nucleus reactions revealed transfer reaction cross-sections equal to or greater than the compound nucleus yields. The data show that in some cases the yield of an isotope produced via a (H.I.,pxn) or (H.I.,αxn) reaction may be higher than its production via an xn compound nucleus reaction. These results have dire consequences for proponents of the ''Z 1 + Z 2 = Z/sub 1+2/'' philosophy. It is no longer acceptable to assume that (H.I.,pxn) and (H.I.,αxn) product yields are of no consequence when studying compound nucleus reactions. No evidence for spontaneous fission decay of 228 Pu, 230 Pu, 232 Cm, or 238 Cf was observed indicating that strictly empirical extrapolations of spontaneous fission half-life data is inadequate for predictions of half-lives for unknown neutron deficient actinide isotopes

  4. Neutron capture in 122,123,124Te: A critical test for s-process studies

    International Nuclear Information System (INIS)

    Wisshak, K.; Voss, F.; Kaeppeler, F.; Reffo, G.

    1991-11-01

    The neutron capture cross sections of 122,123,124,125,126 Te were measured in the energy range from 10 to 200 keV at the Karlsruhe Van de Graaff accelerator using gold as a standard. Neutrons were produced via the 7 Li(p,n) 7 Be reaction by bombarding metallic Li targets with a pulsed proton beam. Capture events were registered with the Karlsruhe 4π Barium Fluoride Detector. Several runs have been performed under different experimental conditions to study the systematic uncertainties in detail. The cross section ratios were determined with an overall uncertainty of ∝ 1%. This is an improvement by about a factor of five compared to the existing data. Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT=10 and 100 keV by normalizing the cross section shape up to 600 keV neutron energy reported in literature to the present data. These stellar cross sections were used in an s-process analysis. With the classical approach the abundances of the three s-only isotopes 122,123,124 Te could be reproduced within the experimental uncertainties of ∝ 1%. The accuracy of the present data allowed also to derive constraints for the existing stellar models with respect to the effective neutron density. Furthermore, the p-process abundances for the tellurium isotopes are discussed. (orig.) [de

  5. Improvement of radiation response characteristic on CdTe detectors using fast neutron irradiation

    International Nuclear Information System (INIS)

    Miyamaru, Hiroyuki; Takahashi, Akito; Iida, Toshiyuki

    1999-01-01

    The treatment of fast neutron pre-irradiation was applied to a CdTe radiation detector in order to improve radiation response characteristic. Electron transport property of the detector was changed by the irradiation effect to suppress pulse amplitude fluctuation in risetime. Spectroscopic performance of the pre-irradiated detector was compared with the original. Additionally, the pre-irradiated detector was employed with a detection system using electrical signal processing of risetime discrimination (RTD). Pulse height spectra of 241 Am, 133 Ba, and 137 Cs gamma rays were measured to examine the change of the detector performance. The experimental results indicated that response characteristic for high-energy photons was improved by the pre-irradiation. The combination of the pre-irradiated detector and the RTD processing was found to provide further enhancement of the energy resolution. Application of fast neutron irradiation effect to the CdTe detector was demonstrated. (author)

  6. Radiochemical studies of neutron deficient actinide isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Williams, K.E.

    1978-04-01

    The production of neutron deficient actinide isotopes in heavy ion reactions was studied using alpha, gamma, x-ray, and spontaneous fission detection systems. A new isotope of berkelium, /sup 242/Bk, was produced with a cross-section of approximately 10 ..mu..b in reactions of boron on uranium and nitrogen on thorium. It decays by electron capture with a half-life of 7.0 +- 1.3 minutes. The alpha-branching ratio for this isotope is less than 1% and the spontaneous fission ratio is less than 0.03%. Studies of (Heavy Ion, pxn) and (Heavy Ion, ..cap alpha..xn) transfer reactions in comparison with (Heavy ion, xn) compound nucleus reactions revealed transfer reaction cross-sections equal to or greater than the compound nucleus yields. The data show that in some cases the yield of an isotope produced via a (H.I.,pxn) or (H.I.,..cap alpha..xn) reaction may be higher than its production via an xn compound nucleus reaction. These results have dire consequences for proponents of the ''Z/sub 1/ + Z/sub 2/ = Z/sub 1+2/'' philosophy. It is no longer acceptable to assume that (H.I.,pxn) and (H.I.,..cap alpha..xn) product yields are of no consequence when studying compound nucleus reactions. No evidence for spontaneous fission decay of /sup 228/Pu, /sup 230/Pu, /sup 232/Cm, or /sup 238/Cf was observed indicating that strictly empirical extrapolations of spontaneous fission half-life data is inadequate for predictions of half-lives for unknown neutron deficient actinide isotopes.

  7. Shape coexistence in the neutron-deficient Pt isotopes in a configuration mixing IBM

    International Nuclear Information System (INIS)

    Morales, Irving O.; Vargas, Carlos E.; Frank, Alejandro

    2004-01-01

    The recently proposed matrix-coherent state approach for configuration mixing IBM is used to describe the evolving geometry of the neutron deficient Pt isotopes. It is found that the Potential Energy Surface (PES) of the Platinum isotopes evolves, when the number of neutrons decreases, from spherical to oblate and then to prolate shapes, in agreement with experimental measurements. Oblate-Prolate shape coexistence is observed in 194,192Pt isotopes

  8. Neutron scattering studies of a dilute magnetic semiconductor: Cd1-xMnxTe

    DEFF Research Database (Denmark)

    Steigenberger, Ursula; Lebech, Bente; Galazka, Robert R.

    1986-01-01

    The development of the magnetic ordering in the magnetic semiconductor Cd1-xMnxTe was investigated by elastic neutron scattering. A detailed study of the correlation length and the intensity as a function of temperature, direction in reciprocal space and concentration of the magnetic ions has been...

  9. Structure of Se-Te glasses studied using neutron, X-ray diffraction and reverse Monte Carlo modelling

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Keiji, E-mail: itoh@okayama-u.ac.jp [Graduate School of Education, Okayama University, Tsushima-naka, Okayama 700-8530 (Japan); Research Reactor Institute, Kyoto University, Kumatori, Osaka 590-0494 (Japan)

    2017-02-15

    Pulsed neutron diffraction and synchrotron X-ray diffraction measurements were performed on Se{sub 100-x}Te{sub x} bulk glasses with x=10, 20, 30 and 40. The coordination numbers obtained from the diffraction results demonstrate that Se and Te atoms are twofold coordinated and the glass structure is formed by the chain network. The three-dimensional structure model for Se{sub 60}Te{sub 40} glass obtained by using reverse Monte Carlo modelling shows that the alternating arrangements of Se and Te atoms compose the major part of the chain clusters but several other fragments such as Se{sub n} chains and Te-Te dimers are also present in large numbers. The chain clusters have geometrically disordered forms and the interchain atomic order is different from those in the crystal structures of trigonal Se and trigonal Te. - Graphical abstract: Coordination environment in Se{sub 60}Te{sub 40} glass.

  10. Deformation and mixing of co-existing shapes in the neutron-deficient polonium isotopes

    CERN Document Server

    AUTHOR|(CDS)2078559; Huyse, Mark

    The neutron-deficient polonium isotopes, with only 2 protons outside the Z = 82 shell closure, are situated in an interesting region of the nuclear chart. In the neighboring lead (Z = 82) and mercury (Z = 80) isotopes, experimental and theoretical efforts identified evidence of shape coexistence. Shape coexistence is the remarkable phenomenon in which two or more distinct types of deformation occur in states of the same angular momentum and similar excitation energy in a nucleus. The neutron-deficient polonium isotopes have also been studied intensively, experimentally as well as theoretically. The closed neutron-shell nucleus 210Po (N = 126) manifests itself as a two-particle nucleus where most of the excited states can be explained by considering the degrees of freedom of the two valence protons outside of 208Pb. The near-constant behavior of the yrast 2+1 and 4+1 states in the isotopes with mass 200 ≤ A ≤ 208 can be explained by coupling the two valence protons to a vibrating lead core. 200Po seems to ...

  11. Spallation production of neutron deficient radioisotopes in North America

    International Nuclear Information System (INIS)

    Jamriska, D.J.; Peterson, E.J.; Carty, J.

    1997-01-01

    The United States Department of Energy produces a number of neutron deficient radioisotopes by high energy proton induced spallation reactions in accelerators at Los Alamos National Laboratory in New Mexico and Brookhaven National Laboratory in New York. Research isotopes are also recovered from targets irradiated at TRIUMF in British Columbia, Canada. The radioisotopes recovered are distributed for use in nuclear medicine, environmental research, physics research, and industry worldwide. In addition to the main product line of Sr-82 from either Mo or Rb targets, Cu-67 from ZnO targets, and Ge-68 from RbBr targets, these irradiation facilities also produce some unique isotopes in quantities not available from any other source such as Be-10, Al-26, Mg-28, Si-32, El-44, Fe-52, Gd-248, and Hg-194. We will describe the accelerator irradiation facilities at the Los Alamos and Brookhaven National Laboratories. The high level radiochemical processing facilities at Los Alamos and brief chemical processes from Los Alamos and Brookhaven will be described. Chemical separation techniques have been developed to recover the radioisotopes of interest in both high radiochemical purity and yield and at the same time trying to reduce or eliminate the generation of mixed waste. nearly 75 neutron deficient radioisotopes produced in spallation targets have been produced and distributed to researchers around the world since the inception of the program in 1974

  12. Potassium Disorder in the Defect Pyrochlore KSbTeO6: A Neutron Diffraction Study

    Directory of Open Access Journals (Sweden)

    José Antonio Alonso

    2017-01-01

    Full Text Available KSbTeO6 defect pyrochlore has been prepared from K2C2O4, Sb2O3, and 15% excess TeO2 by solid-state reaction at 850 °C. Direct methods implemented in the software EXPO2013 allowed establishing the basic structural framework. This was followed by a combined Rietveld refinement from X-ray powder diffraction (XRD and neutron powder diffraction (NPD data, which unveiled additional structural features. KSbTeO6 is cubic, a = 10.1226(7 Å, space group F d 3 ¯ m , Z = 8 and it is made of a mainly covalent framework of corner-sharing (Sb,TeO6 octahedra, with weakly bonded K+ ions located within large cages. The large K-O distances, 3.05(3–3.07(3 Å, and quite large anisotropic atomic displacement parameters account for the easiness of K+ exchange for other cations of technological importance.

  13. Laser spectroscopy of neutron deficient Sn isotopes

    CERN Multimedia

    We propose to study the ground state properties of neutron-deficient Sn isotopes towards the doubly-magic nucleus $^{100}$Sn. Nuclear spins, changes in the rms charge radii and electromagnetic moments of $^{101-121}$Sn will be measured by laser spectroscopy using the CRIS experimental beam line. These ground-state properties will help to clarify the evolution of nuclear structure properties approaching the $\\textit{N = Z =}$ 50 shell closures. The Sn isotopic chain is currently the frontier for the application of state-of-the-art ab-initio calculations. Our knowledge of the nuclear structure of the Sn isotopes will set a benchmark for the advances of many-body methods, and will provide an important test for modern descriptions of the nuclear force.

  14. Collinear Resonance Ionization Spectroscopy of Neutron-Deficient Francium Isotopes

    CERN Document Server

    Flanagan, K T; Ruiz, R F Garcia; Budincevic, I; Procter, T J; Fedosseev, V N; Lynch, K M; Cocolios, T E; Marsh, B A; Neyens, G; Strashnov, I; Stroke, H H; Rossel, R E; Heylen, H; Billowes, J; Rothe, S; Bissell, M L; Wendt, K D A; de Groote, R P; De Schepper, S

    2013-01-01

    The magnetic moments and isotope shifts of the neutron-deficient francium isotopes Fr202-205 were measured at ISOLDE-CERN with use of collinear resonance ionization spectroscopy. A production-to-detection efficiency of 1\\% was measured for Fr-202. The background from nonresonant and collisional ionization was maintained below one ion in 10(5) beam particles. Through a comparison of the measured charge radii with predictions from the spherical droplet model, it is concluded that the ground-state wave function remains spherical down to Fr-205, with a departure observed in Fr-203 (N = 116).

  15. Disorder and transport properties of In3SbTe2 - an X-ray, neutron and electron diffraction study

    International Nuclear Information System (INIS)

    Schroeder, Thorsten; Rosenthal, Tobias; Grott, Sebastian; Stiewe, Christian; Boor, Johannes de; Oeckler, Oliver

    2013-01-01

    Quenched metastable In 3 SbTe 2 was investigated by X-ray and neutron powder diffraction as well as by single-crystal X-ray diffraction. The average structure corresponds to the rocksalt type, the anion position being occupied by antimony and tellurium. Neutron data indicate no antisite disorder of indium and antimony. The compound is a high-temperature phase that can be quenched to yield a metastable compound at ambient temperature which, upon heating, decomposes at ca. 320 C into InSb and InTe. Diffuse scattering in reconstructed X-ray and selected area electron diffraction patterns indicates local distortions of the crystal structure due to static atom displacement along <100> from the average positions, caused by the different size of the anions, but no superstructure. The electrical conductivity of In 3 SbTe 2 is 3.2 x 10 4 S.cm -1 at 25 C, the temperature characteristics correspond to metallic behavior. Consequently, the thermal conductivity is also rather high. The decomposition into InSb and InTe reduces the electrical conductivity by a factor of 3 in heterogeneous microstructures. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Shape coexistence in the neutron-deficient Pt isotopes in the configuration-mixed IBM

    International Nuclear Information System (INIS)

    Vargas, Carlos E.; Campuzano, Cuauhtemoc; Morales, Irving O.; Frank, Alejandro; Van Isacker, Piet

    2008-01-01

    The matrix-coherent state approach in the IBM with configuration mixing is used to describe the geometry of neutron-deficient Pt isotopes. Employing a parameter set for all isotopes determined previously, it is found that the lowest minimum goes from spherical to oblate and finally acquires a prolate shape when approaching the mid-shell Pt isotopes

  17. Mechanism of fission of neutron-deficient actinoids nuclides

    International Nuclear Information System (INIS)

    Sueki, Keisuke; Nakahara, Hiromichi; Tanase, Masakazu; Nagame, Yuichiro; Shinohara, Nobuo; Tsukada, Kazuaki.

    1996-01-01

    A heavy ion reaction ( 19 F+ 209 Bi) is selected. The reaction produces neutron-deficient 228 U which is compound nucleus with a pair of Rb(z=37) and Cs(Z=55). Energy dissipation problem of nucleus was studied by measuring the isotope distribution of two fissile nuclides. Bismuth metal evaporated on aluminium foil was irradiated by 19 F with the incident energy of 105-128 MeV. We concluded from the results that the excess energy of reaction system obtained with increasing the incident energy is consumed by (1) light Rb much more than Cs and (2) about 60% of energy is given to two fission fragments and the rest 40% to the translational kinetic energy or unknown anomalous γ-ray irradiation. (S.Y.)

  18. 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

  19. Semiconductor Thermal Neutron Detector

    Directory of Open Access Journals (Sweden)

    Toru Aoki

    2014-02-01

    Full Text Available The  CdTe  and  GaN  detector  with  a  Gd  converter  have  been developed  and  investigated  as  a  neutron  detector  for neutron  imaging.  The  fabricated  Gd/CdTe  detector  with  the  25  mm  thick  Gd  was  designed  on  the  basis  of  simulation results  of  thermal  neutron  detection  efficiency  and  spatial  resolution.  The  Gd/CdTe  detector  shows  the  detection  of neutron  capture  gamma  ray  emission  in  the  155Gd(n,  g156Gd,  157Gd(n,  g158Gd  and  113Cd(n,  g114Cd  reactions  and characteristic X-ray emissions due to conversion-electrons generated inside the Gd film. The observed efficient thermal neutron detection with the Gd/CdTe detector shows its promise in neutron radiography application. Moreover, a BGaN detector has also investigated to separate neutron signal from gamma-ray clearly. 

  20. Laserspectroscopic studies of collective properties of neutron deficient Ba nuclei

    International Nuclear Information System (INIS)

    Bekk, K.; Andl, A.; Goering, S.; Hanser, A.; Nowicki, G.; Rebel, H.; Schatz, G.

    1979-01-01

    Isotope shifts and hyperfine structure of the BaI resonance-line (lambda=553.6 nm) have been measured by dye laser induced resonance fluorescence on an atomic beam for sup(135m,129g,129m,126) Ba thus extending previous high resolution measurements of neutron deficient Ba nuclides (N - isomers sup(135m) Ba and sup(135m) Ba show a decreased staggering. Conspicuously the isomer shift of the g 7/2 + isomer sup(129m) Ba proves to be negative. The nuclear structure information is discussed in the context of gamma-spectroscopic studies of transitional nuclei with 50 [de

  1. Further studies of neutron-deficient Sn-isotopes using REX-ISOLDE

    CERN Multimedia

    Larsen, A; Syed naeemul, H; Siem, S

    2007-01-01

    Encouraged by the committee to submit the latter part of our latest addendum to experiment IS418 under a new heading this proposal focuses on the second physics case mentioned there. We propose to use Coulomb excitation of odd mass neutron-deficient Sn isotopes to study some dominantly "one quasi-particle" states in these nuclei. Due to spin selection rules these states are difficult to populate following either $\\beta$-decay or in a cascade after a fusion-evaporation reactions, whereas the excitation from the ground-state is of E2 character for some of the most interesting cases.

  2. New neutron-deficient isotopes of barium and rare-earth elements

    CERN Document Server

    Bogdanov, D D; Karnaukhov, V A; Petrov, L A; Plochocki, A; Subbotin, V G; Voboril, J

    1976-01-01

    The authors present an investigation of the short-lived neutron- deficient isotopes of barium and rare-earth elements. By using the BEMS-2 isotope separator on a heavy ion beam, 19 new isotopes were produced with mass numbers ranging from 117 to 138. Five of these (/sup 117/Ba, /sup 129,131/Nd and /sup 133,135/Sm) turned out to be delayed proton emitters. The beta -decay probabilities for the new isotopes have been analyzed in terms of the beta -strength function. An analysis of the proton spectrum shape has been performed using the statistical model for delayed proton emission.

  3. Fast neutron radiation induced Glu-B1 deficient lines of an elite bread wheat variety

    Science.gov (United States)

    Five isogenic wheat lines deficient in high-molecular weight subunit (HMW-GS) proteins encoded by the B-genome were identified from a fast-neutron radiation-mutagenized population of Summit, an elite variety of bread wheat (Triticum aestivum L.). The mutant lines differ from the wild-type progenit...

  4. Mechanism of fission of neutron-deficient actinoids nuclides

    Energy Technology Data Exchange (ETDEWEB)

    Sueki, Keisuke; Nakahara, Hiromichi [Tokyo Metropolitan Univ., Hachioji (Japan). Faculty of Science; Tanase, Masakazu; Nagame, Yuichiro; Shinohara, Nobuo; Tsukada, Kazuaki

    1996-01-01

    A heavy ion reaction ({sup 19}F+{sup 209}Bi) is selected. The reaction produces neutron-deficient {sup 228}U which is compound nucleus with a pair of Rb(z=37) and Cs(Z=55). Energy dissipation problem of nucleus was studied by measuring the isotope distribution of two fissile nuclides. Bismuth metal evaporated on aluminium foil was irradiated by {sup 19}F with the incident energy of 105-128 MeV. We concluded from the results that the excess energy of reaction system obtained with increasing the incident energy is consumed by (1) light Rb much more than Cs and (2) about 60% of energy is given to two fission fragments and the rest 40% to the translational kinetic energy or unknown anomalous {gamma}-ray irradiation. (S.Y.)

  5. Probing shape coexistence in neutron-deficient $^{72}$Se via low-energy Coulomb excitation

    CERN Multimedia

    We propose to study the evolution of nuclear structure in neutron-­deficient $^{72}$Se by performing a low-­energy Coulomb excitation measurement. Matrix elements will be determined for low-­lying excited states allowing for a full comparison with theoretical predictions. Furthermore, the intrinsic shape of the ground state, and the second 0$^{+}$ state, will be investigated using the quadrupole sum rules method.

  6. Experimental investigation of decay properties of neutron deficient $^{116-118}$Ba isotopes and test of $^{112-115}$Ba beam counts

    CERN Multimedia

    We propose to study decay of neutron deficient isotopes $^{116-118}$Ba using Double Sided Silicon Strip Detector (DSSSD). To study delayed-proton and $\\alpha$-decay branching ratios of $^{116-118}$Ba are of special interest because of their vicinity to the proton drip line. The nuclear life-times and properties of the proton unstable states of Cs isotopes, populated through decay of $^{116-118}$Ba isotopes will be measured. In addition to that we propose beam development of $^{112-115}$Ba to study exotic decay properties of these neutron deficient nuclei and to search for super-allowed $\\alpha$-decay in future.

  7. Thermal neutron capture cross sections of tellurium isotopes

    International Nuclear Information System (INIS)

    Tomandl, I.; Honzatko, J.; Egidy, T. von; Wirth, H.-F.; Belgya, T.; Lakatos, M.; Szentmiklosi, L.; Revay, Zs.; Molnar, G.L.; Firestone, R.B.; Bondarenko, V.

    2003-01-01

    New values for thermal neutron capture cross sections of the tellurium isotopes 122 Te, 124 Te, 125 Te, 126 Te, 128 Te, and 130 Te are reported. These values are based on a combination of newly determined partial γ-ray cross sections obtained from experiments on targets contained natural Te and γ intensities per capture of individual Te isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given

  8. Thermal neutron capture cross sections of tellurium isotopes

    International Nuclear Information System (INIS)

    Tomandl, I.; Honzatko, J.; Egidy, T. von; Wirth, H.-F.; Belgya, T.; Lakatos, M.; Szentmiklosi, L.; Revay, Zs.; Molnar, G.L.; Firestone, R.B.; Bondarenko, V.

    2004-01-01

    New values for thermal neutron capture cross sections of the tellurium isotopes 122Te, 124Te, 125Te, 126Te, 128Te, and 130Te are reported. These values are based on a combination of newly determined partial g-ray cross sections obtained from experiments on targets contained natural Te and gamma intensities per capture of individual Te isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given

  9. Thermal neutron capture cross sections of tellurium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Tomandl, I.; Honzatko, J.; von Egidy, T.; Wirth, H.-F.; Belgya, T.; Lakatos, M.; Szentmiklosi, L.; Revay, Zs.; Molnar, G.L.; Firestone, R.B.; Bondarenko, V.

    2004-03-01

    New values for thermal neutron capture cross sections of the tellurium isotopes 122Te, 124Te, 125Te, 126Te, 128Te, and 130Te are reported. These values are based on a combination of newly determined partial g-ray cross sections obtained from experiments on targets contained natural Te and gamma intensities per capture of individual Te isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given.

  10. Shape transition and coexistence in neutron-deficient rare earth isotopes

    CERN Multimedia

    We propose to study spectroscopic quadrupole moments of excited states and electromagnetic transition rates between them in the neutron-deficient rare earth nuclei $^{140}$Sm and $^{142}$Gd using projectile Coulomb excitation at energies of 4.7 MeV per nucleon. The rare earth nuclei below the N=82 shell closure form one of the few regions of the nuclear chart where oblate shapes are expected to occur near the ground state. Nuclear shapes are expected to change rapidly in this region, with coexistence of oblate and prolate shapes in some nuclei. The measurement of electromagnetic matrix elements represents therefore a particularly sensitive test of theoretical nuclear structure models.

  11. Measurement of cross sections producing short-lived nuclei by 14MeV neutron. Cd, Sn, Te, Nd, Gd, Re

    Energy Technology Data Exchange (ETDEWEB)

    Sakane, H.; Yamamoto, H.; Kawade, K. [Nagoya Univ. (Japan); Iida, T.; Takahashi, A.

    1998-03-01

    Nine neutron activation cross sections producing the nuclei with half-lives between 25sec and 22min were measured at energy range between 13.4 and 14.9 MeV by activation method. The (n,p) and (n,{alpha}) reaction cross sections were measured for the isotopes of {sup 110}Cd, {sup 112}Sn, {sup 122}Te, {sup 130}Te and {sup 185}Re and those of {sup 130}Te, {sup 148}Nd and {sup 158}Gd, respectively. The present results were compared with our systematics proposed on the basis of 58 cross section data of (n,p) and 33 data of (n,{alpha}) reaction. Good agreements have been seen between them. (author)

  12. Multi-quasiparticle excitation: Extending shape coexistence in A∼190 neutron-deficient nuclei

    International Nuclear Information System (INIS)

    Shi Yue; Liu, H. L.; Xu, F. R.; Walker, P. M.

    2010-01-01

    Multi-quasiparticle high-K states in neutron-deficient mercury, lead, and polonium isotopes have been investigated systematically by means of configuration-constrained potential-energy-surface calculations. An abundance of high-K states is predicted with both prolate and oblate shapes, which extends the shape coexistence of the mass region. Well-deformed shapes provide good conditions for the formation of isomers, as exemplified in 188 Pb. Of particular interest is the prediction of low-lying 10 - states in polonium isotopes, which indicate long-lived isomers.

  13. Gamma spectroscopic studies of the neutron-deficient g-g nucleus 74Kr by means of a neutron multiplicity measurement technique

    International Nuclear Information System (INIS)

    Roth, J.

    1981-01-01

    The g-g nucleus 74 Kr was studied by means of the reaction 58 Ni ( 19 F, p2n#betta#) 74 Kr. In order to make gamma spectroscopic studies at neutron deficient nuclei like 74 Kr a neutron multiplicity measurement technique was developed. Beside #betta# single spectra, #betta# excitation functions, #betta#-#betta# coincidences, #betta# angular distributions, and lifetime measurements by means of this technique all measurements in coincidence with up to two neutrons were taken up. From these measurement data an extended term scheme with 17 newly found excited states could be extracted. To all levels spins and parities could be assigned. From the four energetically lowest levels of the yrast cascade the mean lifetimes could be determined. A double backbending in the sequence of the yrast cascade was interpreted as crossing of the g 9/2 bands. The irregularities in the lower part of the yrast band correspond to the shape consistence picture. The results were considered in connection with the systematics of the even krypton isotopes and compared with a two-quasiparticle-plas-rotor model calculation. (HSI)

  14. 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.

  15. Commissioning of a new photon detection system for charge radii measurements of neutron-deficient Ca

    Science.gov (United States)

    Watkins, J.; Garand, D.; Miller, A. J.; Minamisono, K.; Everett, N.; Powel, R. C.; Maaß, B.; Nörtershäuser, W.; Kalman, C.; Lantis, J.; Kujawa, C.; Mantica, P.

    2017-09-01

    Calcium is unique for its possession of two stable isotopes of ``doubly magic'' nuclei at proton and neutron numbers (Z , N) = (20 , 20) and (20 , 28) . Recent charge radii measurements of neutron-rich calcium isotopes yielded an upward trend beyond current theoretical predictions. At the BECOLA facility at NSCL/MSU, Ca charge radii measurements will be extended to the neutron-deficient regime using collinear laser spectroscopy. A new photon detection system with an ellipsoidal reflector and a compound parabolic concentrator has been commissioned for the experiment. The system increases the signal-to-noise ratio by reducing background, which is critical for the low production rates of the Ca experiment. Details of the system and results of the characterization tests will be discussed. Work supported in part by NSF Grant PHY-15-65546, U.S. DOE Grant DE-NA0002924 and by the Deutsche Forschungsgemeinschaft Grant SFB 1245.

  16. Evolution of local structure in Ag2O-TeO2 glasses with addition of Ag2O analyzed by pulsed neutron diffraction and Raman spectroscopy

    International Nuclear Information System (INIS)

    Iwadate, Yasuhiko; Suzuki, Mineta; Hattori, Takeo; Fukushima, Kazuko; Nishiyama, Shin; Misawa, Masakatsu; Fukunaga, Toshiharu; Itoh, Keiji

    2005-01-01

    The local structure of Ag 2 O-TeO 2 glasses was studied by time-of-flight pulsed neutron diffraction (TOF-PND) and Raman spectroscopy. The results of Raman spectroscopy indicated that TeO 4 trigonal bipyramidal units (tbp) were converted to TeO 3 trigonal pyramidal units (tp) by addition of Ag 2 O to TeO 2 . Furthermore in PND, the structural parameters for each atomic pair were optimized in the Q-space, and the distances of the near neighbor Te-O correlations forming tbp units and tp units in the network were estimated with some accuracy

  17. β Decay in the Region of Neutron-deficient {sup 69,70,71}Kr

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, A.M., E-mail: ARogers@lbl.gov [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA, 94720 (United States); Giovinazzo, J. [Centre d' Etudes Nucléaires de Bordeaux-Gradignan, Université Bordeaux 1, UMR 5797 CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175, Gardignan Cedex (France); Lister, C.J. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Blank, B.; Canchel, G. [Centre d' Etudes Nucléaires de Bordeaux-Gradignan, Université Bordeaux 1, UMR 5797 CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175, Gardignan Cedex (France); Clark, J.A. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); France, G. de; Grévy, S. [GANIL CEA/DSM-CNRS/IN2P3, Boulevard Henri Becquerel, BP55027, 14076 CEAN Cedex 5 (France); Gros, S.; McCutchan, E.A. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Oliveira Santos, F. de [GANIL CEA/DSM-CNRS/IN2P3, Boulevard Henri Becquerel, BP55027, 14076 CEAN Cedex 5 (France); Savard, G.; Seweryniak, D. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Stefan, I.; Thomas, J.-C. [GANIL CEA/DSM-CNRS/IN2P3, Boulevard Henri Becquerel, BP55027, 14076 CEAN Cedex 5 (France)

    2014-06-15

    Decay spectroscopy was performed for neutron-deficient nuclei ranging from zinc to krypton with isospin −3/2 ≤T{sub z}≤0. Measurements of correlated β-delayed protons allowed us to determine the isobaric analog states fed from the decay of {sup 65}Se and {sup 69}Kr, constraining the spin of the {sup 69}Kr ground state. Preliminary results regarding the half lives for the T{sub z}=−1 systems, relevant to the rapid proton capture (rp) process, are discussed.

  18. Physics with Heavy Neutron Rich Ribs at the Hribf

    Science.gov (United States)

    Radford, David

    2002-10-01

    The Holifield Radioactive Ion Beam Facility at the Oak Ridge National Laboratory has recently produced the world's first post-accelerated beams of heavy neutron-rich nuclei. B(E2;0^+ arrow 2^+) values for neutron-rich ^126,128Sn and ^132,134,136Te isotopes have been measured by Coulomb excitation of radioactive ion beams in inverse kinematics. The results for ^132Te and ^134Te (N=80,82) show excellent agreement with systematics of lighter Te isotopes, but the B(E2) value for ^136Te (N=84) is unexpectedly small. Single-neutron transfer reactions leading to ^135Te were identified using a ^134Te beam on ^natBe and ^13C targets at energies just above the Coulomb barrier. The use of the Be target provided an unambiguous signature for neutron transfer through the detection of two correlated α particles, arising from the breakup of unstable ^8Be. The results of these experiments will be discussed, togther with plans for future experiments with these heavy n-rich RIBs.

  19. Spectroscopy of light neutron deficient nuclei: 31Ar and 27S decays

    International Nuclear Information System (INIS)

    Borrel, V.

    1991-01-01

    Light neutron-deficient nuclei exhibit several interesting decay modes. In some cases, beta-delayed alpha emission becomes possible, and beta-delayed three-proton emission can be allowed. The energy spectra of the emitted protons should give informations on the position of the isobaric analog state and on its deexcitation modes. Experimental results obtained at GANIL with the LISE spectrometer on the decay of the isotopes 31 Ar and 27 S are presented. These data are discussed and compared with the predicted isobaric analog state excitation energies and with shell-model calculations. (G.P.) 13 refs.; 7 figs.; 1 tab

  20. Measurements of competing structures in neutron-deficient Pb isotopes by employing Coulomb excitation

    CERN Multimedia

    Bastin, B; Kruecken, R; Larsen, A; Rahkila, P J; Srebrny, J; Clement, E; Wadsworth, R; Syed naeemul, H; Peura, P J; Siem, S; Hadynska-klek, K; Habs, D; Napiorkowski, P J; Diriken, J V J; Iwanicki, J S

    Coulomb excitation measurements to study the shape coexistence and quadrupole collectivity of the low-lying levels in neutron-deficient Pb nuclei are proposed. Even-mass $^{188−192}$Pb nuclei will be post-accelerated at REX-ISOLDE in order to measure transition probabilities and quadrupole moments for the first excited states. In combination with results obtained in lifetime measurements, this will allow the sign of the quadrupole deformation parameter to be extracted for the first time for 2$^{+}$ states in the even-mass $^{188−192}$Pb nuclei.

  1. Measurements of electric quadrupole moments of neutron-deficient Au, Pt, and Ir nuclei with NMR-ON in hcp-Co

    CERN Multimedia

    Smolic, E; Hagn, E; Zech, E; Seewald, G

    2002-01-01

    The aim of the experiments is the measurement of $\\,$i) nuclear magnetic moments and electric quadrupole moments of neutron-deficient isotopes in the region Os-Ir-Pt-Au with the methods of quadrupole-interaction-resolved NMR on oriented nuclei " QI-NMR-ON " and modulated adiabatic passage on oriented nuclei " MAPON " and $\\,$ii) the magnetic hyperfine field, electric field gradient (EFG), and spin-lattice relaxation of 5d elements in ferromagnetic Fe, Ni, fcc-Co and hcp-Co.\\\\ The measurements on Au isotopes have been finished successfully. The quadrupole moments of $^{186}$Au, $^{193m}$Au, $^{195}$Au, $^{195m}$Au, $^{197m}$Au, $^{198}$Au and $^{199}$Au were determined with high precision.\\\\ For neutron-deficient Ir isotopes QI-NMR-ON measurements were performed after implantation of Hg precursors. The EFG of Ir in hcp-Co has been calibrated. Thus precise values for the spectroscopic quadrupole mo...

  2. Measurement of the cross section for electromagnetic dissociation with neutron emission in Pb-Pb collisions at √SNN=2.76 TeV

    International Nuclear Information System (INIS)

    Abelev, B.; Garishvili, I.; Soltz, R.; Adam, J.; Bielcik, J.; Cepila, J.; Krelina, M.; Krus, M.; Pachr, M.; Petracek, V.; Petran, M.; Pospisil, V.; Smakal, R.; Tlusty, D.; Wagner, V.; Zach, C.; Vajzer, M.; Adamova, D.; Bielcikova, J.; Kushpil, S.; Kushpil, V.; Sumbera, M.; Adare, A.M.; Aronsson, T.; Caballero Orduna, D.; Caines, H.; Harris, J.W.; Hicks, B.; Hille, P.T.; Ma, R.; Oh, S.; Smirnov, N.; Aggarwal, M.M.; Bhati, A.K.; Chawla, I.; Rathee, D.; Sharma, N.; Aglieri Rinella, G.; Augustinus, A.; Baltasar Dos Santos Pedrosa, F.; Betev, L.; Brun, R.; Carena, F.; Carena, W.; Carminati, F.; Cavicchioli, C.; Chapeland, S.; Chibante Barroso, V.; Chochula, P.; Conesa del Valle, Z.; Costa, F.; Del Castillo Sanchez, E.; Di Mauro, A.; Divia, R.; Floris, M.; Fuchs, U.; Gheata, A.; Agocs, A.G.; Barnafoldi, G.G.; Bencedi, G.; Berenyi, D.; Boldizsar, L.; Denes, E.; Hamar, G.; Levai, P.; Agostinelli, A.; Arcelli, S.; Basile, M.; Bellini, F.; Cifarelli, L.; Falchieri, D.; Guerzoni, B.; Scioli, G.; Zichichi, A.; Aguilar Salazar, S.; Alfaro Molina, R.; Almaraz Avina, E.; Belmont-Moreno, E.; Cruz Alaniz, E.; Gonzalez-Trueba, L.H.; Grabski, V.; Martinez Davalos, A.; Menchaca-Rocha, A.; Ahammed, Z.; Basu, S.; Chattopadhyay, S.; Choudhury, S.; De, S.; Dubey, A.K.; Dutta Majumdar, M.R.; Ghosh, P.; Khan, S.A.; Mohanty, B.; Muhuri, S.; Mukherjee, M.; Nayak, T.K.; Baldisseri, A.; Borel, H.; Castillo Castellanos, J.; Charvet, J.L.; Geuna, C.; Pereira Da Costa, H.; Rakotozafindrabe, A.; Yang, H.

    2012-01-01

    The first measurement of neutron emission in electromagnetic dissociation of 208 Pb nuclei at the LHC is presented. The measurement is performed using the neutron zero degree calorimeters of the ALICE experiment, which detect neutral particles close to beam rapidity. The measured cross sections of single and mutual electromagnetic dissociation of Pb nuclei at √S NN = 2.76 TeV with neutron emission are σ singleEMD =187.4 ± 0.2(stat) +13.2 -11.2 (syst) b and σ mutualEMD = 5.7±0.1(stat) ± 0.4(syst) b, respectively. The experimental results are compared to the predictions from a relativistic electromagnetic dissociation model. (authors)

  3. Spallation production of neutron deficient radioisotopes in North America

    International Nuclear Information System (INIS)

    Jamriska, D.J.; Peterson, E.J.; Carty, J.

    1997-01-01

    The US Department of Energy produces a number of neutron deficient radioisotopes by high energy proton induced spallation reactions in accelerators at Los Alamos National Laboratory in New Mexico and Brookhaven National Laboratory in New York. Research isotopes are also recovered from targets irradiated at TRIUMF in British Columbia, Canada. The radioisotopes recovered are distributed for use in nuclear medicine, environmental research, physics research, and industry worldwide. In addition to the main product line of Sr-82 from either Mo or Rb targets, Cu-67 from ZnO targets, and Ge-68 and RbBr targets, these irradiation facilities also produce some unique isotopes in quantities not available from any other source such as Al-26, Mg-28, Si-32, Ti-44, Fe-52, Gd-148, and Hg-194. The authors will describe the accelerator irradiation facilities at the Los Alamos and Brookhaven National Laboratories. The high level radiochemical processing facilities at Los Alamos and brief chemical processes will be described

  4. Laser spectroscopy of neutron deficient gold and platinum isotopes

    International Nuclear Information System (INIS)

    Savard, G.

    1988-03-01

    A new method for on-line laser spectroscopy of radioactive atoms based on the resonant ionization spectroscopy of laser-desorbed radioactive samples has been devised. An experimental setup has been installed on-line at the ISOCELE mass separator in Orsay (France) and experiments have been performed on the region of transitional nuclei around Z=79. Isotopic shift measurements on four new isotopes 194 Au, 196 Au, 198 Au, 199 Au have been performed on gold and results on the neutron deficient isotopes down to 186 Au have been obtained confirming the nuclear ground-state shape transition from oblate to prolate between 187 Au and 186 Au. The first isotopic shift measurements on radioactive platinum isotopes have been obtained on 186 Pt, 188 Pt, 189 Pt. Indications of a shape transition have been observed between 186 Pt and 188 Pt. The extracted experimental changes in mean square charge radii δ 2 > A,A' along isotopic chains are compared to self-consistent Hartree-Fock plus BCS calculations

  5. Study of oblate nuclear shapes and shape coexistence in neutron-deficient rare earth isotopes

    CERN Multimedia

    Guttormsen, M S; Reiter, P; Larsen, A; Korten, W; Clement, E; Siem, S; Renstrom, T; Buerger, A; Jenkins, D G

    We propose to investigate nuclear shapes and shape coexistence in neutron-deficient rare earth nuclei below the N=82 shell closure at the ISOLDE facility by employing Coulomb excitation of Nd, Sm, Gd, and Dy beams from the REX accelerator and the Miniball experiment. Nuclear shapes are expected to change rapidly in this region of the nuclear chart. The measurement of electric quadrupole moments of excited states and the transition rates between them serves as a stringent test of theoretical models and effective nucleon-nucleon interactions.

  6. Coulomb Excitation of Neutron Deficient Sn-Isotopes using REX-ISOLDE

    CERN Multimedia

    Di julio, D D; Kownacki, J M; Marechal, F; Andreoiu, C; Siem, S; Perrot, F; Van duppen, P L E; Napiorkowski, P J; Iwanicki, J S

    2002-01-01

    It is proposed to study the evolution of the reduced transition probabilities, B(E2; 0$^{+} \\rightarrow$ 2$^{+}$), for neutron deficient Sn isotopes by Coulomb excitation in inverse kinematics using REX-ISOLDE and the MINIBALL detector array. Measurements of the reduced transition matrix element for the transition between the ground state and the first excited 2$^{+}$ state in light even-even Sn isotopes provide a means to study e.g. core polarization effects in the $^{100}$Sn core. Previous attempts to measure this quantity have been carried out using the decay of isomeric states populated in fusion evaporation reactions. We thus propose to utilize the unique opportunity provided by REX-ISOLDE, after the energy upgrade to 3.1 MeV/u, to use the more model-independent approach of Coulomb excitation to measure this quantity in a number of isotopes in this region.

  7. Prevalence of Nutritional Deficiencies in Hair Loss among Indian Participants: Results of a Cross-sectional Study.

    Science.gov (United States)

    Gowda, Dinesh; Premalatha, V; Imtiyaz, D B

    2017-01-01

    Nutritional deficiencies are known to be associated with hair loss; however, the exact prevalence is not known. The aim of this study is to evaluate the prevalence of nutritional deficiencies in participants with hair loss. In this cross-sectional study, 100 enrolled participants were divided into telogen effluvium (TE), male-pattern hair loss (MPHL), and female-pattern hair loss (FPHL) based on the type of hair loss. All participants underwent laboratory estimation for micronutrients and amino acid levels. Participants with hair loss showed varied amino acid and micronutrient deficiencies across all types of hair loss. Nutritional status did not vary much between the types of hair loss. Among the essential amino acids, histidine deficiency was seen in >90% of participants with androgenic alopecia and 77.78% of participants with TE while leucine deficiency was seen 98.15% of participants with TE and 100% with FPHL. Valine deficiency was also very common across alopecia subtypes. Among the nonessential amino acids, alanine deficiency was observed in 91.67% FPHL, 91.18% MPHL, and 90.74% TE. Cysteine deficiency was present in 55.58% and 50% of participants with MPHL and TE, respectively. A relatively higher proportion of participants with TE had iron deficiency compared to androgenic alopecia ( P = 0.069). Zinc deficiency was seen in 11.76% of participants with MPHL while copper deficiency was seen in 29.41% and 31.48% of participants with MPHL and TE, respectively. Nutritional deficiency is a common problem in participants with hair loss irrespective of the type of alopecia. The findings of our study suggest need for identification and correction of nutritional deficiencies in patients with hair loss.

  8. Long-lived high-spin isomers in the neutron-deficient 1g sub(9/2)-shell nuclei

    International Nuclear Information System (INIS)

    Ogawa, K.

    1981-09-01

    The neutron-deficient 1g sub(9/2)-shell nuclei are studied in the framework of the shell model with active nucleons occuping the 1g sub(9/2) and 2p sub(1/2) shells. The calculated result for 95 Pd shows good agreement with the recent experiment by Nolte and Hick. Many ''spin-gap'' Isomers are predicted in the region of A = 76 -- 84 and A = 95 -- 100. (author)

  9. Measurement of the Cross Section for Electromagnetic Dissociation with Neutron Emission in Pb-Pb Collisions at √sNN = 2.76 TeV

    CERN Document Server

    Abelev, Betty; Adamova, Dagmar; Adare, Andrew Marshall; Aggarwal, Madan; Aglieri Rinella, Gianluca; Agocs, Andras Gabor; Agostinelli, Andrea; Aguilar Salazar, Saul; Ahammed, Zubayer; Ahmad, Arshad; Ahmad, Nazeer; Ahn, Sang Un; Akindinov, Alexander; Aleksandrov, Dmitry; Alessandro, Bruno; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Almaraz Avina, Erick Jonathan; Alme, Johan; Alt, Torsten; Altini, Valerio; Altinpinar, Sedat; Altsybeev, Igor; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshauser, Harald; Arbor, Nicolas; Arcelli, Silvia; Arend, Andreas; Armesto, Nestor; Arnaldi, Roberta; Aronsson, Tomas Robert; Arsene, Ionut Cristian; Arslandok, Mesut; Augustinus, Andre; Averbeck, Ralf Peter; Awes, Terry; Aysto, Juha Heikki; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bailhache, Raphaelle Marie; Bala, Renu; Baldini Ferroli, Rinaldo; Baldisseri, Alberto; Baldit, Alain; Baltasar Dos Santos Pedrosa, Fernando; Ban, Jaroslav; Baral, Rama Chandra; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Barret, Valerie; Bartke, Jerzy Gustaw; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batyunya, Boris; Baumann, Christoph Heinrich; Bearden, Ian Gardner; Beck, Hans; Belikov, Iouri; Bellini, Francesca; Bellwied, Rene; Belmont-Moreno, Ernesto; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhati, Ashok Kumar; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Bjelogrlic, Sandro; Blanco, F; Blanco, Francesco; Blau, Dmitry; Blume, Christoph; Bock, Nicolas; Bogdanov, Alexey; Boggild, Hans; Bogolyubsky, Mikhail; Boldizsar, Laszlo; Bombara, Marek; Book, Julian; Borel, Herve; Borissov, Alexander; Bose, Suvendu Nath; Bossu, Francesco; Botje, Michiel; Bottger, Stefan; Boyer, Bruno Alexandre; Braidot, Ermes; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Browning, Tyler Allen; Broz, Michal; Brun, Rene; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Bugaiev, Kyrylo; Busch, Oliver; Buthelezi, Edith Zinhle; Caballero Orduna, Diego; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calvo Villar, Ernesto; Camerini, Paolo; Canoa Roman, Veronica; Cara Romeo, Giovanni; Carena, Francesco; Carena, Wisla; Carminati, Federico; Casanova Diaz, Amaya Ofelia; Castillo Castellanos, Javier Ernesto; Casula, Ester Anna Rita; Catanescu, Vasile; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Charvet, Jean-Luc Fernand; Chattopadhyay, Sukalyan; Chattopadhyay, Subhasis; Chawla, Isha; Cherney, Michael Gerard; Cheshkov, Cvetan; Cheynis, Brigitte; Chiavassa, Emilio; Chibante Barroso, Vasco Miguel; Chinellato, David; Chochula, Peter; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Coccetti, Fabrizio; Colamaria, Fabio; Colella, Domenico; Conesa Balbastre, Gustavo; Conesa del Valle, Zaida; Constantin, Paul; Contin, Giacomo; Contreras, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortes Maldonado, Ismael; Cortese, Pietro; Cosentino, Mauro Rogerio; Costa, Filippo; Cotallo, Manuel Enrique; Crochet, Philippe; Cruz Alaniz, Emilia; Cuautle, Eleazar; Cunqueiro, Leticia; D'Erasmo, Ginevra; Dainese, Andrea; Dalsgaard, Hans Hjersing; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Kushal; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; de Barros, Gabriel; De Caro, Annalisa; de Cataldo, Giacinto; de Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; de Rooij, Raoul Stefan; Del Castillo Sanchez, Eduardo; Delagrange, Hugues; Deloff, Andrzej; Demanov, Vyacheslav; Denes, Ervin; Deppman, Airton; Di Bari, Domenico; Di Giglio, Carmelo; Di Liberto, Sergio; Di Mauro, Antonio; Di Nezza, Pasquale; Diaz Corchero, Miguel Angel; Dietel, Thomas; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Dominguez, Isabel; Donigus, Benjamin; Dordic, Olja; Driga, Olga; Dubey, Anand Kumar; Ducroux, Laurent; Dupieux, Pascal; Dutta Majumdar, AK; Dutta Majumdar, Mihir Ranjan; Elia, Domenico; Emschermann, David Philip; Engel, Heiko; Erdal, Hege Austrheim; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Evans, David; Eyyubova, Gyulnara; Fabris, Daniela; Faivre, Julien; Falchieri, Davide; Fantoni, Alessandra; Fasel, Markus; Fearick, Roger Worsley; Fedunov, Anatoly; Fehlker, Dominik; Feldkamp, Linus; Felea, Daniel; Fenton-Olsen, Bo; Feofilov, Grigory; Fernandez Tellez, Arturo; Ferretti, Alessandro; Ferretti, Roberta; Figiel, Jan; Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Fragkiadakis, Michail; Frankenfeld, Ulrich Michael; Fuchs, Ulrich; Furget, Christophe; Fusco Girard, Mario; Gaardhoje, Jens Joergen; Gagliardi, Martino; Gago, Alberto; Gallio, Mauro; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Garabatos, Jose; Garcia-Solis, Edmundo; Garishvili, Irakli; Gerhard, Jochen; Germain, Marie; Geuna, Claudio; Gheata, Andrei George; Gheata, Mihaela; Ghidini, Bruno; Ghosh, Premomoy; Gianotti, Paola; Girard, Martin Robert; Giubellino, Paolo; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez, Ramon; Gonzalez Ferreiro, Elena; Gonzalez-Trueba, Laura Helena; Gonzalez-Zamora, Pedro; Gorbunov, Sergey; Goswami, Ankita; Gotovac, Sven; Grabski, Varlen; Graczykowski, Lukasz Kamil; Grajcarek, Robert; Grelli, Alessandro; Grigoras, Alina Gabriela; Grigoras, Costin; Grigoriev, Vladislav; 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Ilkiv, Iryna; Inaba, Motoi; Incani, Elisa; Innocenti, Gian Michele; Ippolitov, Mikhail; Irfan, Muhammad; Ivan, Cristian George; Ivanov, Andrey; Ivanov, Marian; Ivanov, Vladimir; Ivanytskyi, Oleksii; Jacholkowski, Adam Wlodzimierz; Jacobs, Peter; Jancurova, Lucia; Jangal, Swensy Gwladys; Janik, Malgorzata Anna; Janik, Rudolf; Jayarathna, Sandun; Jena, Satyajit; Jha, Deeptanshu Manu; Jimenez Bustamante, Raul Tonatiuh; Jirden, Lennart; Jones, Peter Graham; Jung, Hyung Taik; Jusko, Anton; Kakoyan, Vanik; Kalcher, Sebastian; Kalinak, Peter; Kalisky, Matus; Kalliokoski, Tuomo Esa Aukusti; Kalweit, Alexander Philipp; Kanaki, Kalliopi; Kang, Ju Hwan; Kaplin, Vladimir; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karpechev, Evgeny; Kazantsev, Andrey; Kebschull, Udo Wolfgang; Keidel, Ralf; Khan, Mohisin Mohammed; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Beomkyu; Kim, Dong Jo; Kim, Do Won; Kim, Jonghyun; Kim, Jin Sook; Kim, Minwoo; Kim, Se Yong; Kim, Seon Hee; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Klay, Jennifer Lynn; Klein, Jochen; Klein-Bosing, Christian; Kliemant, Michael; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Koch, Kathrin; Kohler, Markus; Kolojvari, Anatoly; Kondratiev, Valery; Kondratyeva, Natalia; Konevskih, Artem; Korneev, Andrey; Kour, Ravjeet; Kowalski, Marek; Kox, Serge; Koyithatta Meethaleveedu, Greeshma; Kral, Jiri; Kralik, Ivan; Kramer, Frederick; Kraus, Ingrid Christine; Krawutschke, Tobias; Krelina, Michal; Kretz, Matthias; Krivda, Marian; Krizek, Filip; Krus, Miroslav; Kryshen, Evgeny; Krzewicki, Mikolaj; Kucheriaev, Yury; Kuhn, Christian Claude; Kuijer, Paul; Kurashvili, Podist; Kurepin, A; Kurepin, AB; Kuryakin, Alexey; Kushpil, Svetlana; Kushpil, Vasily; Kweon, Min Jung; Kwon, Youngil; La Pointe, Sarah Louise; La Rocca, Paola; Ladron de Guevara, Pedro; Lakomov, Igor; Langoy, Rune; Lara, Camilo Ernesto; Lardeux, Antoine Xavier; Lazzeroni, Cristina; Le Bornec, Yves; Lea, Ramona; Lechman, Mateusz; Lee, Ki Sang; Lee, Sung Chul; Lefevre, Frederic; Lehnert, Joerg Walter; Leistam, Lars; Lemmon, Roy Crawford; Lenhardt, Matthieu Laurent; Lenti, Vito; Leon Monzon, Ildefonso; Leon Vargas, Hermes; Leoncino, Marco; Levai, Peter; Lien, Jorgen; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Liu, Lijiao; Loenne, Per-Ivar; Loggins, Vera; Loginov, Vitaly; Lohn, Stefan Bernhard; Lohner, Daniel; Loizides, Constantinos; Loo, Kai Krister; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lovhoiden, Gunnar; Lu, Xianguo; Luettig, Philipp; Lunardon, Marcello; Luo, Jiebin; Luparello, Grazia; Luquin, Lionel; Luzzi, Cinzia; Ma, Rongrong; Maevskaya, Alla; Mager, Magnus; Mahapatra, Durga Prasad; Maire, Antonin; Mal'Kevich, Dmitry; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Ludmila; Malzacher, Peter; Mamonov, Alexander; Manceau, Loic Henri Antoine; Manko, Vladislav; Manso, Franck; Manzari, Vito; Mao, Yaxian; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Marin, Ana Maria; Marin Tobon, Cesar Augusto; Markert, Christina; Martashvili, Irakli; Martinengo, Paolo; Martinez, Mario Ivan; Martinez Davalos, Arnulfo; Martinez Garcia, Gines; Martynov, Yevgen; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Mastromarco, Mario; Mastroserio, Annalisa; Matthews, Zoe Louise; Matyja, Adam Tomasz; Mayani, Daniel; Mayer, Christoph; Mazer, Joel; Mazzoni, Alessandra Maria; Meddi, Franco; Menchaca-Rocha, Arturo Alejandro; Mercado Perez, Jorge; Meres, Michal; Miake, Yasuo; Milano, Leonardo; Milosevic, Jovan; Mischke, Andre; Mishra, Aditya Nath; Miskowiec, Dariusz; Mitu, Ciprian Mihai; Mlynarz, Jocelyn; Mohanty, Ajit Kumar; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Monteno, Marco; Montes, Esther; Moon, Taebong; Morando, Maurizio; Moreira De Godoy, Denise Aparecida; Moretto, Sandra; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhuri, Sanjib; Mukherjee, Maitreyee; Muller, Hans; Munhoz, Marcelo; Musa, Luciano; Musso, Alfredo; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Nattrass, Christine; Naumov, Nikolay; Navin, Sparsh; Nayak, Tapan Kumar; Nazarenko, Sergey; Nazarov, Gleb; Nedosekin, Alexander; Nicassio, Maria; Nielsen, Borge Svane; Niida, Takafumi; Nikolaev, Sergey; Nikolic, Vedran; Nikulin, Sergey; Nikulin, Vladimir; Nilsen, Bjorn Steven; Nilsson, Mads Stormo; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Novitzky, Norbert; Nyanin, Alexandre; Nyatha, Anitha; Nygaard, Casper; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Oleniacz, Janusz; Oppedisano, Chiara; Ortiz Velasquez, Antonio; Ortona, Giacomo; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Pachmayer, Yvonne Chiara; Pachr, Milos; Padilla, Fatima; Pagano, Paola; Paic, Guy; Painke, Florian; Pajares, Carlos; Pal, S; Pal, Susanta Kumar; Palaha, Arvinder Singh; Palmeri, Armando; Papikyan, Vardanush; Pappalardo, Giuseppe; Park, Woo Jin; Passfeld, Annika; Patalakha, Dmitri Ivanovich; Paticchio, Vincenzo; Pavlinov, Alexei; Pawlak, Tomasz Jan; Peitzmann, Thomas; Pereira Da Costa, Hugo Denis Antonio; Pereira De Oliveira Filho, Elienos; Peresunko, Dmitri; Perez Lara, Carlos Eugenio; Perez Lezama, Edgar; Perini, Diego; Perrino, Davide; Peryt, Wiktor Stanislaw; Pesci, Alessandro; Peskov, Vladimir; Pestov, Yury; Petracek, Vojtech; Petran, Michal; Petris, Mariana; Petrov, Plamen Rumenov; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Piccotti, Anna; Pikna, Miroslav; Pillot, Philippe; Pinazza, Ombretta; Pinsky, Lawrence; Pitz, Nora; Piuz, Francois; Piyarathna, Danthasinghe; Ploskon, Mateusz Andrzej; Pluta, Jan Marian; Pocheptsov, Timur; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Polichtchouk, Boris; Pop, Amalia; Porteboeuf-Houssais, Sarah; Pospisil, Vladimir; Potukuchi, Baba; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puchagin, Sergey; Puddu, Giovanna; Pujol Teixido, Jordi; Pulvirenti, Alberto; Punin, Valery; Putis, Marian; Putschke, Jorn Henning; Quercigh, Emanuele; Qvigstad, Henrik; Rachevski, Alexandre; Rademakers, Alphonse; Radomski, Sylwester; Raiha, Tomi Samuli; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Ramirez Reyes, Abdiel; Raniwala, Rashmi; Raniwala, Sudhir; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Read, Kenneth Francis; Real, Jean-Sebastien; Redlich, Krzysztof; Reichelt, Patrick; Reicher, Martijn; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Rettig, Felix Vincenz; Revol, Jean-Pierre; Reygers, Klaus Johannes; Riccati, Lodovico; Ricci, Renato Angelo; Richert, Tuva; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Rodrigues Fernandes Rabacal, Bartolomeu; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roed, Ketil; Rohr, David; Rohrich, Dieter; Romita, Rosa; Ronchetti, Federico; Rosnet, Philippe; Rossegger, Stefan; Rossi, Andrea; Roukoutakis, Filimon; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Ryabinkin, Evgeny; Rybicki, Andrzej; Sadovsky, Sergey; Safarik, Karel; Sahoo, Raghunath; Sahu, Pradip Kumar; Saini, Jogender; Sakaguchi, Hiroaki; Sakai, Shingo; Sakata, Dosatsu; Salgado, Carlos Albert; Salzwedel, Jai; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sanchez Castro, Xitzel; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Sano, Satoshi; Santo, Rainer; Santoro, Romualdo; Sarkamo, Juho Jaako; Scapparone, Eugenio; Scarlassara, Fernando; Scharenberg, Rolf Paul; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schreiner, Steffen; Schuchmann, Simone; Schukraft, Jurgen; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Patrick Aaron; Scott, Rebecca; Segato, Gianfranco; Selyuzhenkov, Ilya; Senyukov, Serhiy; Seo, Jeewon; Serci, Sergio; Serradilla, Eulogio; Sevcenco, Adrian; Sgura, Irene; Shabetai, Alexandre; Shabratova, Galina; Shahoyan, Ruben; Sharma, Natasha; Sharma, Satish; Shigaki, Kenta; Shimomura, Maya; Shtejer, Katherin; Sibiriak, Yury; Siciliano, Melinda; Sicking, Eva; Siddhanta, Sabyasachi; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, catherine; Simonetti, Giuseppe; Singaraju, Rama Narayana; Singh, Ranbir; Singha, Subhash; Sinha, Bikash; Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Skjerdal, Kyrre; Smakal, Radek; Smirnov, Nikolai; Snellings, Raimond; Sogaard, Carsten; Soltz, Ron Ariel; Son, Hyungsuk; Song, Jihye; Song, Myunggeun; Soos, Csaba; Soramel, Francesca; Sputowska, Iwona; Spyropoulou-Stassinaki, Martha; Srivastava, Brijesh Kumar; Stachel, Johanna; Stan, Ionel; Stefanek, Grzegorz; Stefanini, Giorgio; Steinbeck, Timm Morten; Steinpreis, Matthew; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Stolpovskiy, Mikhail; Strabykin, Kirill; Strmen, Peter; Suaide, Alexandre Alarcon do Passo; Subieta Vasquez, Martin Alfonso; Sugitate, Toru; Suire, Christophe Pierre; Sukhorukov, Mikhail; Sultanov, Rishat; Sumbera, Michal; Susa, Tatjana; Szanto de Toledo, Alejandro; Szarka, Imrich; Szczepankiewicz, Adam; Szostak, Artur Krzysztof; Tagridis, Christos; Takahashi, Jun; Tapia Takaki, Daniel Jesus; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terrevoli, Cristina; Thader, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony; Tlusty, David; Toia, Alberica; Torii, Hisayuki; Tosello, Flavio; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ulery, Jason Glyndwr; Ullaland, Kjetil; Ulrich, Jochen; Uras, Antonio; Urban, Jozef; Urciuoli, Guido Marie; Usai, Gianluca; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vallero, Sara; van der Kolk, Naomi; van Leeuwen, Marco; Vande Vyvre, Pierre; Vannucci, Luigi; Vargas, Aurora Diozcora; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vechernin, Vladimir; Veldhoen, Misha; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Vikhlyantsev, Oleg; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Vinogradov, Alexander; Vinogradov, Leonid; Vinogradov, Yury; Virgili, Tiziano; Viyogi, Yogendra; Vodopianov, Alexander; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; von Haller, Barthelemy; Vranic, Danilo; Øvrebekk, Gaute; Vrlakova, Janka; Vulpescu, Bogdan; Vyushin, Alexey; Wagner, Boris; Wagner, Vladimir; Wan, Renzhuo; Wang, Dong; Wang, Mengliang; Wang, Yifei; Wang, Yaping; Watanabe, Kengo; Wessels, Johannes; Westerhoff, Uwe; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Alexander; Wilk, Grzegorz Andrzej; Williams, Crispin; Windelband, Bernd Stefan; Xaplanteris Karampatsos, Leonidas; Yaldo, Chris G; Yang, Hongyan; Yang, Shiming; Yasnopolsky, Stanislav; Yi, JunGyu; Yin, Zhongbao; Yoo, In-Kwon; Yoon, Jongik; Yu, Weilin; Yuan, Xianbao; Yushmanov, Igor; Zach, Cenek; Zampolli, Chiara; Zaporozhets, Sergey; Zarochentsev, Andrey; Zavada, Petr; Zaviyalov, Nikolai; Zbroszczyk, Hanna Paulina; Zelnicek, Pierre; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhou, Daicui; Zhou, Fengchu; Zhou, You; Zhu, Jianhui; Zhu, Xiangrong; Zichichi, Antonino; Zimmermann, Alice; Zinovjev, Gennady; Zoccarato, Yannick Denis; Zynovyev, Mykhaylo

    2012-01-01

    The first measurement of neutron emission in electromagnetic dissociation of 208Pb nuclei at the LHC is presented. The measurement is performed using the neutron Zero Degree Calorimeters of the ALICE experiment, which detect neutral particles close to beam rapidity. The measured cross sections of single and mutual electromagnetic dissociation of Pb nuclei at √sNN = 2.76 TeV with neutron emission are σ_single EMD = 187.2±0.2 (stat.) +13.8−12.0 (syst.) b and σ_mutual EMD = 6.2 ± 0.1 (stat.) ±0.4 (syst.) b respectively. The experimental results are compared to the predictions from a relativistic electromagnetic dissociation model.

  10. Projected shell model study of yrast states of neutron-deficient odd-mass Pr nuclei

    International Nuclear Information System (INIS)

    Ibanez-Sandoval, A.; Ortiz, M. E.; Velazquez, V.; Galindo-Uribarri, A.; Hess, P. O.; Sun, Y.

    2011-01-01

    A wide variety of modern instruments allow us to study neutron-deficient nuclei in the A=130 mass region. Highly deformed nuclei have been found in this region, providing opportunities to study the deformed rotational bands. The description of the 125,127,129,131,133 Pr isotopes with the projected shell model is presented in this paper. Good agreement between theory and experiment is obtained and some characteristics are discussed, including the dynamic moment of inertia J (2) , kinetic moment of inertia J (1) , the crossing of rotational bands, and backbending effects.

  11. Measurement of cross sections producing short-lived nuclei by 14 MeV neutron. Br, Te, Dy, Ho, Yb

    Energy Technology Data Exchange (ETDEWEB)

    Sakane, H.; Matsumoto, T.; Yamamoto, H.; Kawade, K. [Nagoya Univ. (Japan); Iida, T.; Takahashi, A.

    1997-03-01

    Nine neutron activation cross sections producing the nuclei with half-lives between 2 min and 57 min have been measured at energy range between 13.4 and 14.9 MeV for Br, Te, Dy, Ho, Yb. The cross sections of {sup 81}Br(n,p){sup 81m}Se, {sup 128}Te(n,p){sup 128m}Sb, {sup 128}Te(n,{alpha}){sup 125m}Sn, {sup 164}Dy(n,p){sup 164}Tb, {sup 165}Ho(n,{alpha}){sup 162}Tb, {sup 176}Yb(n,p){sup 176}Tm were newly obtained at the six energy points between 13.4-14.9 MeV, although the previous results have been obtained at one energy point. {sup 79}Br(n,2n){sup 78}Br, {sup 164}Dy(n,p){sup 164}Tb are compared with evaluated data of JENDL-3.2. The evaluations for these reactions agree reasonably well with experimental results. The cross sections of (n,p) reaction are compared with systematics by Kasugai et. al. The systematics agrees with experimental results. (author)

  12. Spectroscopy of heavy nuclei by configuration mixing of symmetry restored mean-field states: shape coexistence in neutron-deficient Pb isotopes

    International Nuclear Information System (INIS)

    Bender, M.; Heenen, P.H.; Bonche, P.; Duguet, T.

    2003-01-01

    We study shape coexistence and low-energy excitation spectra in neutron-deficient Pb isotopes using configuration mixing of angular-momentum and particle-number projected self-consistent mean-field states. The same Skyrme interaction SLy6 is used everywhere in connection with a density-dependent zero-range pairing force. (orig.)

  13. Nuclear charge radii and nuclear moments of neutron deficient Ba isotopes from high resolution laser spectroscopy

    International Nuclear Information System (INIS)

    Nowicki, G.; Bekk, K.; Goering, S.; Hanser, A.; Rebel, H.; Schatz, G.

    1978-07-01

    Isotope shifts and hyperfine structure of the BaI 6s 2 1 S 0 -6s6p 1 P 1 transitions (lambda = 553.6 nm) in neutron deficient Ba nuclides (N 131 Ba, 128 Ba, in addition to remeasurements of all stable Ba nuclides. The extracted values of delta 2 >, the observed odd-even staggering and the nuclear moments are discussed in the light of other theoretical and experimental nuclear structure studies of the region 50 [de

  14. First observation of excited structures in neutron-deficient 179Hg : evidence for multiple shape coexistence

    International Nuclear Information System (INIS)

    Kondev, F.G.; Carpenter, M.P.; Janssens, R.V.F.; Lister, C.J.; Abu Saleem, K.; Ahmad, I.; Amro, H.; Caggiano, J.; Davids, C.N.; Heinz, A.; Herskind, B.; Khoo, T.L.; Lauristen, T.; Ma, W.C.; Ressler, J.J.; Reviol, W.; Riedinger, L.L.; Sarantites, D.G.; Seweryniak, D.; Siem, S.; Sonzongni, A.A.; Varmette, P.G.; Wiedenhoever, I.

    2002-01-01

    Excited structures in the neutron-deficient nucleus 179 Hg have been established for the first time using the Gammasphere spectrometer in conjunction with the fragment mass analyzer. Competing states originating from three different minima associated with nearly spherical, oblate, and prolate deformations were found. This result can be contrasted with the situation in heavier odd-mass Hg isotopes where only two minima (oblate and prolate) have been seen. The implications of these three shapes at low spin and excitation energy are discussed in the general context of shape coexistence in this mass region.

  15. Shape coexistence measurements in even-even neutron-deficient polonium isotopes by Coulomb excitation, using REX-ISOLDE and the Ge MINIBALL array

    CERN Multimedia

    Butler, P; Bastin, B; Kruecken, R; Voulot, D; Rahkila, P J; Orr, N A; Srebrny, J; Grahn, T; Clement, E; Paul, E S; Gernhaeuser, R A; Dorsival, A; Diriken, J V J; Huyse, M L; Iwanicki, J S

    The neutron-deficient polonium isotopes with two protons outside the closed Z=82 shell represent a set of nuclei with a rich spectrum of nucleus structure phenomena. While the onset of the deformation in the light Po isotopes is well established experimentally, questions remain concerning the sign of deformation and the magnitude of the mixing between different configurations. Furthermore, controversy is present with respect to the transition from the vibrational-like character of the heavier Po isotopes to the shape coexistence mode observed in the lighter Po isotopes. We propose to study this transition in the even-mass neutron-deficient $^{198,200,202}$Po isotopes by using post-accelerated beams from REX-ISOLDE and "safe"-energy Coulomb excitation. $\\gamma$- rays will be detected by the MINIBALL array. The measurements of the Coulomb excitation differential cross section will allow us to deduce both the transition and diagonal matrix elements for these nuclei and, combined with lifetime measurements, the s...

  16. Characterization of L-cysteine capped CdTe quantum dots and application to test Cu(II) deficiency in biological samples from critically ill patients

    Energy Technology Data Exchange (ETDEWEB)

    Sáez, Laura; Molina, Jorge; Florea, Daniela I.; Planells, Elena M. [Institute of Nutrition and Food Technology and Department of Physiology, Faculty of Pharmacy, Campus Cartuja, University of Granada, E-18071 Granada (Spain); Cabeza, M. Carmen [Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, E-18071 Granada (Spain); Quintero, Bartolomé, E-mail: bqosso@ugr.es [Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, E-18071 Granada (Spain)

    2013-06-27

    Graphical abstract: -- Highlights: •We examinate stability of L-cysteine capped CdTe QD. •Factors influence QD fluorescence response are controlled. •Application in copper deficiency analysis is made. •We report comparison with other techniques. -- Abstract: The catalytic activity of copper ion gives, from the physiological point of view, a central role in many biological processes. Variations in the composition and location of cellular copper have been addressed given their physiological and pathological consequences. In this paper L-cysteine capped CdTe quantum dots is used for the fluorimetric determination of Cu(II) in biological samples from healthy individuals and patients admitted to the Intensive Care Units (ICU). An acceptable homogeneity in the CdTe QDs size has been obtained with an average value of 3 nm. No significant alterations in the spectral properties were observed for 2 months when stored in vacutainers at 6 °C and a concentration of approximately 2 μM. Data from oxidative stress markers such superoxide dismutase, total antioxidant capacity and DNA damage can be correlated with a Cu(II) deficiency for the ICU patients as measured by flame-atomic absorption spectroscopy (FAAS) and inductively coupled plasma source mass spectrometry (ICP-MS). Aqueous solutions 0.3 μM of L-cysteine capped CdTe QDs in MOPS buffer (6 mM, pH 7.4) used at 21 °C in the range 15–60 min after preparation of the sample for the measurements of fluorescence gives contents in Cu(II) for erythrocytes in good agreement with those obtained in FAAS and ICP-MS but the comparative ease of use makes the fluorimetric technique more suitable than the other two techniques for routine analysis.

  17. In situ neutron scattering study of nanostructured PbTe-PbS bulk thermoelectric material

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Fei [Temple University; Schmidt, Robert D [ORNL; Case, Eldon D [Michigan State University, East Lansing; An, Ke [ORNL

    2016-01-01

    Nanostructures play an important role in thermoelectric materials. Their thermal stability, such as phase change and evolution at elevated temperatures, is thus of great interest to the thermoelectric community. In this study, in situ neutron diffraction was used to examine the phase evolution of nanostructured bulk PbTe-PbS materials fabricated using hot pressing and pulsed electrical current sintering (PECS). The PbS second phase was observed in all samples in the as-pressed condition. The temperature dependent lattice parameter and phase composition data show an initial formation of PbS precipitates followed by a redissolution during heating. The redissolution process started around 570 600 K, and completed at approximately 780 K. During cooling, the PECS sample followed a reversible curve while the heating/cooling behavior of the hot pressed sample was irreversible.

  18. Nuclear structure studies in highly neutron-deficient (114,116)Xe

    Science.gov (United States)

    Degraaf, James Hendrick

    Lifetimes of nuclear states in 114Xe and 116Xe were measured for the first time; these nuclei represent the most neutron-deficient isotopes of xenon for which lifetimes have now been measured. The fusion-evaporation reactions 58Ni(60Ni, 2p)116Xe at 223 MeV beam energy and 58Ni(58Ni, 2p)114Xe at 215 MeV beam energy were used. Lifetimes were measured using the Recoil Distance Method (RDM) with the 8π gamma-ray spectrometer at Chalk River Laboratories. The new measurements of the B(E2;2+/to 0+) strength in these nuclei, coupled with the recent measurements for heavier xenon isotopes, are well described within the framework of the O(6) symmetry limit of the Interacting Boson Approximation. The octupole nature of the negative parity side-band was also studied, and the lifetime measurements indicate a change from a K/approx 3 structure in heavier xenon isotopes to a K/approx 0,/ 1 structure in 114Xe.

  19. Study of neutron deficient iridium isotopes by using laser spectroscopy; Etude des noyaux d'iridium deficients en neutrons par spectroscopie laser

    Energy Technology Data Exchange (ETDEWEB)

    Verney, D

    2000-12-19

    Resonance ionization spectroscopy was performed on neutron deficient iridium isotopes {sup 182-189}Ir, {sup 186}Ir{sup m} and stable isotopes {sup 191,193}Ir. Hyperfine spectra were recorded from the optical transition at 351,7 nm between the 5d{sup 7}6s{sup 2} {sup 4}F{sub 9/2} ground state and the 5d{sup 7}6s6p {sup 6}F{sub 11/2} excited state. Radioactive iridium isotopes were obtained from {beta}{sup +}/EC decay of radioactive mercury nuclei deposited on a graphite substrate. The radioactive mercury nuclei were produced at the ISOLDE facility at CERN through spallation reactions, by bombarding a molten lead target with the 1 GeV proton beam delivered by the PS-Booster. Magnetic dipole moments and spectroscopic quadrupole moments were extracted from the hyperfine spectra. The mean square charge radius variations, as deduced from the measured isotopic shift, show a sharp change between {sup 187}Ir and {sup 186}Ir{sup g}, accompanied by a sudden increase in deformation: from {beta}2 {approx} 0,16 to {beta}2 > 0, 2. These results were analysed in the framework of an axial rotor plus one or two quasiparticles. The wave functions of the osmium and platinum cores which are used in order to describe the iridium nuclei were calculated from the HF+BCS method with the Skyrme SIII effective interaction. The cores were constrained to take the deformation parameters extracted from the isotopic shift measurements. One shows then that this sudden deformation change corresponds also to a change in the proton state that describes the odd nuclei ground state or that participates in the coupling with the neutron in odd-odd nuclei. This state is identified with the {pi}3/2{sup +}[402] orbital for the smaller deformations nuclei and with the {pi}1/2{sup -}[541] orbital stemming from the h{sub 9/2} subshell for bigger deformations nuclei. (author)

  20. Neutron scattering study of the magnetic phases of USb0.8Te0.2

    DEFF Research Database (Denmark)

    Langridge, S.; Stirling, W.G.; Nuttall, W.J.

    1995-01-01

    The magnetic phases of USb0.8Te0.2 have been studied by neutron diffraction. Above the ordering temperature a detailed study has been made of the critical scattering and of the anisotropy between correlations parallel and perpendicular to the ordering wave vector....

  1. Structure of TeO2 - LiNbO3 glasses

    Science.gov (United States)

    Shinde, A. B.; Krishna, P. S. R.; Rao, Rekha

    2017-05-01

    Tellurite based lithium niobate glasses with composition (100-x)TeO2-xLiNbO3 (x=0.1,0.2 & 0.3) were prepared by conventional melt quenching method. The microscopic structural investigation of these glasses is carried out by means of neutron diffraction and Raman scattering measurements. It is found that the basic structural units in these glasses are TeO4 trigonal bipyramids(TBP), TeO3 trigonal pyramids(TP) and NbO6 Octahedra depending on the composition. It is evident from Raman studies that TBPs decreases, TPs increases and NbO6 Octahedra increases with increasing x. From Neutron diffraction studies it is found that network is comprised of TBPs and TPs along with TeO3+1 structural units. Distorted NbO6 octahedral units are present and also increase with the increase in x.

  2. The properties of atomic nuclei at the boundary of proton instability, discussed at the example of very neutron deficient isotopes in the mass range 100-150

    International Nuclear Information System (INIS)

    Roeckl, E.

    1981-10-01

    In this paper it shall be tried to strike the balance after the first years of experimenting at the on-line mass separator of the GSI Darmstadt and to present the main results of the study of very neutron deficient isotopes in the mass range 90-150 as well as the resulting questions for further experiments. First some foundations concerning the properties of neutron deficient nuclei and the measuring method are explained. The results and their interpretation are discussed using examples for the alpha decay, the beta decay, the mass-energy-area, and the proton-drip line. Finally the obtained results are summarized, and an outlook to further studies of nuclear properties far from beta stability is given. (orig.) [de

  3. Paschos-Wolfenstein relationship for nuclei and the NuTeV sin2θW measurement

    International Nuclear Information System (INIS)

    Kulagin, S.A.

    2003-01-01

    We discuss the nuclear effects in the Paschos-Wolfenstein relationship in the context of the extraction of the weak mixing angle. We point out that the neutron excess correction to the Paschos-Wolfenstein relationship for a neutron-rich target is negative and large on the scale of the experimental errors of a recent NuTeV measurement. We find a larger neutron excess correction to the Paschos-Wolfenstein relationship for the total cross sections than that discussed by the NuTeV Collaboration. The phenomenological applications of this observation are discussed in the context of the NuTeV deviation. The uncertainties in the neutron excess correction are estimated. The effects due to the Fermi motion, nuclear binding, and nuclear shadowing are also discussed in the context of the total cross sections

  4. Search for EC-decayed neutron-deficient actinide isotopes using gas-jet coupled JAERI-ISOL

    Energy Technology Data Exchange (ETDEWEB)

    Tsukada, Kazuaki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    To study the nuclear properties of unknown neutron deficient actinide isotopes which decay mainly via orbital electron capture (EC), we have developed a composite system consisting of a gas-jet transport apparatus and a thermal ion-source at the JAERI-ISOL. With this system, search for {sup 236}Am produced in the {sup 235}U({sup 6}Li, 5n) reaction has been performed. Pu KX-rays associated with the EC decay of {sup 236}Am are observed at the mass-236 fraction. The half-life of {sup 236}Am is evaluated to be 4.4min. The outline of the gas-jet coupled JAERI-ISOL system and typical performance are given. (author)

  5. Penning-trap mass spectrometry and mean-field study of nuclear shape coexistence in the neutron-deficient lead region

    Science.gov (United States)

    Manea, V.; Ascher, P.; Atanasov, D.; Barzakh, A. E.; Beck, D.; Blaum, K.; Borgmann, Ch.; Breitenfeldt, M.; Cakirli, R. B.; Cocolios, T. E.; Day Goodacre, T.; Fedorov, D. V.; Fedosseev, V. N.; George, S.; Herfurth, F.; Kowalska, M.; Kreim, S.; Litvinov, Yu. A.; Lunney, D.; Marsh, B.; Neidherr, D.; Rosenbusch, M.; Rossel, R. E.; Rothe, S.; Schweikhard, L.; Wienholtz, F.; Wolf, R. N.; Zuber, K.

    2017-05-01

    We present a study of nuclear shape coexistence in the region of neutron-deficient lead isotopes. The midshell gold isotopes 180,185,188,190Au (Z =79 ), the two long-lived nuclear states in 197At (Z =85 ), and the neutron-rich nuclide 219At were produced by the ISOLDE facility at CERN and their masses were determined with the high-precision Penning-trap mass spectrometer ISOLTRAP. The studied gold isotopes address the trend of binding energies in a region of the nuclear chart where the nuclear charge radii show pronounced discontinuities. Significant deviations from the atomic-mass evaluation were found for Au,190188. The new trend of two-neutron separation energies is smoother, although it does reveal the onset of deformation. The origin of this effect is interpreted in connection to the odd-even staggering of binding energies, as well as theoretically by Hartree-Fock-Bogoliubov calculations including quasiparticle blocking. The role of blocking for reproducing the large odd-even staggering of charge radii in the mercury isotopic chain is illustrated.

  6. Calorimetric dosimetry in neutron and charged particle beams

    International Nuclear Information System (INIS)

    McDonald, J.C.; Ma, I.C.; Laughlin, J.S.

    1978-01-01

    A portable tissue-equivalent (TE) calorimetric, constructed of A-150 plastic, has been employed for the measurement of absorbed dose in several neutron radiotherapy fields. Comparisons of spherical, cylindrical, and thimble shaped TE ionization chambers have been carried out using either air, or a flow of TE gas in the chamber

  7. Resonant x-ray and neutron diffraction study of USb0.8Te0.2

    DEFF Research Database (Denmark)

    Nuttall, W.J.; Langridge, S.; Stirling, W.G.

    1995-01-01

    Complementary neutron and magnetic x-ray scattering experiments have been performed on the pseudobinary compound USb0.8Te0.2. Both techniques reveal a succession of magnetic phases on cooling. On passing through the Neel temperature (T-N similar to 205 K), the system enters an antiferromagnetic (...

  8. Post-Irradiation Behaviour of I131 in TeO2

    International Nuclear Information System (INIS)

    Jaćimović, Lj.; Stevović, J.; Veljković, S.R.

    1965-01-01

    The system I 131 in TeO 2 is interesting because little is known about thermal chemical changes in this target. Radioiodine was produced by neutron irradiation of TeO 2 in the reactor. Irradiated TeO 2 was dissolved in diluted NaOH. The analysis of the iodine valency forms was made by ion exchange techniques. The thermal and radiation stability of TeO 2 was studied by using the spectrophotometric method for the determination of tellurium. Post-irradiation annealing of I 131 in TeO 2 was studied in dependence on the time and temperature of the heating. The main tendency of annealing was the reduction of radioiodine. The time dependence of this process indicates a fast change at high temperatures. The curves are more complex at lower temperatures. The annealing may appear complex because of the variety of thermal reactions of iodine intermediary. It may react with products of the following processes: tellurium recoil and corresponding hot zone, beta transition of Te 131 and TeO 2 itself. The kinetics of these changes was considered and an estimation of the processes during annealing was made. The influence of the neutron flux on the kinetics of annealing was also studied. (author) [fr

  9. Shape coexistence in the neutron-deficient mercury isotopes studied through Coulomb excitation

    CERN Document Server

    Bree, Nick

    This thesis describes the analysis and results of a series of Coulomb-excitation experiments on even-even neutron-deficient mercury isotopes aimed at obtaining a more detailed description of shape coexistence. Two experimental campaigns have been undertaken in the Summer of 2007 and 2008. Pure beams of 182,184,186,188Hg were produced and accelerated at the REX-ISOLDE radioactive-beam facility, located at CERN (Geneva, Switzerland). The beams were guided to collide with a stable target to induce Coulomb excitation. The scattered particles were registered by a double-sided silicon strip detector, and the emitted gamma rays by the MINIBALL gamma-ray spectrometer. The motivation to study these mercury isotopes, focused around shape coexistence in atomic nuclei, is addressed in chapter 1, as well as an overview of the knowledge in this region of the nuclear chart. A theoretical description of Coulomb excitation is presented in the second chapter, while the third chapter describes the setup employed for the experim...

  10. Comparison of CdZnTe neutron detector models using MCNP6 and Geant4

    Science.gov (United States)

    Wilson, Emma; Anderson, Mike; Prendergasty, David; Cheneler, David

    2018-01-01

    The production of accurate detector models is of high importance in the development and use of detectors. Initially, MCNP and Geant were developed to specialise in neutral particle models and accelerator models, respectively; there is now a greater overlap of the capabilities of both, and it is therefore useful to produce comparative models to evaluate detector characteristics. In a collaboration between Lancaster University, UK, and Innovative Physics Ltd., UK, models have been developed in both MCNP6 and Geant4 of Cadmium Zinc Telluride (CdZnTe) detectors developed by Innovative Physics Ltd. Herein, a comparison is made of the relative strengths of MCNP6 and Geant4 for modelling neutron flux and secondary γ-ray emission. Given the increasing overlap of the modelling capabilities of MCNP6 and Geant4, it is worthwhile to comment on differences in results for simulations which have similarities in terms of geometries and source configurations.

  11. Structure of zinc and niobium tellurite glasses by neutron and x-ray diffraction

    Science.gov (United States)

    Hoppe, U.; Yousef, E.; Rüssel, C.; Neuefeind, J.; Hannon, A. C.

    2004-03-01

    Neutron and x-ray diffraction experiments of high resolving power with neutrons from a spallation source and high-energy photons from a synchrotron have been performed on compositional series of binary Zn, Nb and on mixed Zn/Nb tellurite glasses. The Te-O, Zn-O and Nb-O coordination numbers are determined by Gaussian fitting of the first-neighbour peaks in the neutron and x-ray data simultaneously. The transition of TeO4 to TeO3 units with increasing fraction of a second component is indicated by decreasing total Te-O coordination numbers. This transition appears different for glasses with ZnO or Nb2O5 additions. Details of the Te-O peaks suggest there are two species of Te-O bonds with lengths of {\\sim }0.19 and {\\sim }0.21 nm. The change of their fractions shows excellent agreement with the existence of TeO4 trigonal bipyramids and TeO3 trigonal pyramids. All oxygen atoms from ZnO and Nb2O5 are used for rupture of Te-O-Te bridges, which is accompanied with a change of nearly all participating TeO4 to TeO3 groups. The tendency for a {\\mathrm {TeO}}_{4} \\to {\\mathrm {TeO}}_{3} change decreases for glasses of higher second component content which is accompanied by the occurrence of TeO4 groups with non-bridging oxygens. The Nb tellurite glasses show transition to network-forming behaviour with the formation of Nb-O-Nb bridges. The fractions of TeO3 units of ternary Zn/Nb tellurite glasses agree with an additivity behaviour of the modifying effects of ZnO and Nb2O5 additions. Some of these results have already been presented in thesis work: Yousef E 2003 A study of some physical properties of tellurite glass (Al-Azhar University, Assiut Egypt).

  12. Structure of zinc and niobium tellurite glasses by neutron and x-ray diffraction

    International Nuclear Information System (INIS)

    Hoppe, U; Yousef, E; Ruessel, C; Neuefeind, J; Hannon, A C

    2004-01-01

    Neutron and x-ray diffraction experiments of high resolving power with neutrons from a spallation source and high-energy photons from a synchrotron have been performed on compositional series of binary Zn, Nb and on mixed Zn/Nb tellurite glasses. The Te-O, Zn-O and Nb-O coordination numbers are determined by Gaussian fitting of the first-neighbour peaks in the neutron and x-ray data simultaneously. The transition of TeO 4 to TeO 3 units with increasing fraction of a second component is indicated by decreasing total Te-O coordination numbers. This transition appears different for glasses with ZnO or Nb 2 O 5 additions. Details of the Te-O peaks suggest there are two species of Te-O bonds with lengths of ∼ 0.19 and ∼ 0.21 nm. The change of their fractions shows excellent agreement with the existence of TeO 4 trigonal bipyramids and TeO 3 trigonal pyramids. All oxygen atoms from ZnO and Nb 2 O 5 are used for rupture of Te-O-Te bridges, which is accompanied with a change of nearly all participating TeO 4 to TeO 3 groups. The tendency for a TeO 4 → TeO 3 change decreases for glasses of higher second component content which is accompanied by the occurrence of TeO 4 groups with non-bridging oxygens. The Nb tellurite glasses show transition to network-forming behaviour with the formation of Nb-O-Nb bridges. The fractions of TeO 3 units of ternary Zn/Nb tellurite glasses agree with an additivity behaviour of the modifying effects of ZnO and Nb 2 O 5 additions

  13. Design and construction of the equipment and obtention process of TeO2 for the 131 I production

    International Nuclear Information System (INIS)

    Alanis M, J.

    2000-09-01

    This project was carried out in the National Institute of Nuclear Research, Nuclear Center of Mexico (ININ), with the name 'A New Method to Obtain 131 I by Neutron Irradiation of TeO 2 and it Dry Distillation'. This work establishes the optimal parameters to produce 131 I by neutron irradiation and foundry of TeO 2 sinterized. The TeO 2 of high purity was produced adding HNO 3 to the metallic tellurium (Merck 8100) and heating several samples to different temperatures until dryness in presence of an air current. The optimal conditions of temperature and reaction velocity were obtained, as well as of drying and sintering, to obtain TeO 2 crystals with high purity able to retain the 131 I produced by the radioactive decay. After drying and purified by the heating, the TeO 2 was sinterized, applying a next temperature to it melting point by few minutes, enough to create cavities in the middle of it crystalline structure, where the 131 I in gas form produced by the decay of the 131 Te it is retained, one time that the TeO 2 is bombarded with thermal neutrons in the nuclear reactor. Then, the reactions 130 Te(n, γ) 131 Te m (t 1/2 = 30 h) and 130 Te(n, γ) 131 Te (t 1/2 = 24.8 m) with an optimal irradiation time of 2.5 h. (Author)

  14. A preliminary inter-centre comparison study for photon, thermal neutron and epithermal neutron responses of two pairs of ionisation chambers used for BNCT

    International Nuclear Information System (INIS)

    Roca, Antoaneta; Liu, Yuan-Hao; Wojnecki, Cecile; Green, Stuart; Nievaart, Sander; Ghani, Zamir; Moss, Ray

    2009-01-01

    The dual ionisation chamber technique is the recommended method for mixed field dosimetry of epithermal neutron beams. This paper presents initial data from an ongoing inter-comparison study involving two identical pairs of ionisation chambers used at the BNCT facilities of Petten, NL and of University of Birmingham, UK. The goal of this study is to evaluate the photon, thermal neutron and epithermal neutron responses of both pairs of TE(TE) (Exradin T2 type) and Mg(Ar) (Exradin M2 type) ionisation chambers in similar experimental conditions. At this stage, the work has been completed for the M2 type chambers and is intended to be completed for the T2 type chambers in the near future.

  15. Coulomb excitation of $^{116}$Te and $^{118}$Te: a study of collectivity above the Z = 50 shell gap

    CERN Multimedia

    Cederkall, J A; Smith, J F; Voulot, D; Rahkila, P J; Darby, I G; Hadinia, B; Grahn, T; Paul, E S; Wadsworth, R; Bree, N C F; Baeck, T M; Julin, R J; Diriken, J V J; Jenkins, D G; Kroell, T; Leske, J; Huyse, M L

    We propose to study the nature and collectivity of low-energy excitations in $^{116}$Te and $^{118}$Te. We aim to measure the transition probability of the 0$^{+}$ $\\rightarrow$ 2$^{+}$ transition by means of Coulomb excitation, employing REX-ISOLDE and MINIBALL. The proposed study probes the systematics of B(E2) values in light Te nuclei, which lie in a region of the nuclear chart where unusual phenomena and evolution of collectivity have been observed. The proposed study will shed light on the role of the residual proton-neutron interactions in the development of collectivity when approaching the N = Z line. This is a resubmission of the P-277 proposal. The suggestions of INTC have been taken into account and the data from the Yale $^{120}$Te study has been included.

  16. Study of the odd-${A}$, high-spin isomers in neutron-deficient trans-lead nuclei with ISOLTRAP

    CERN Multimedia

    Herfurth, F; Blaum, K; Beck, D; Kowalska, M; Schwarz, S; Stanja, J; Huyse, M L; Wienholtz, F

    We propose to measure the excitation energy of the $\\frac{13^{+}}{2}$ isomers in the neutron-deficient isotopes $^{193,195,197}$Po with the ISOLTRAP mass spectrometer. The assignment of the low- and high-spin isomers will be made by measuring the energy of the $\\alpha$- particles emitted in the decay of purified beams implanted in a windmill system. Using $\\alpha$-decay information, it is then also possible to determine the excitation energy of the similar isomers in the $\\alpha$-daughter nuclei $^{189,191,193}$Pb, $\\alpha$-parent nuclei $^{197,199,201}$Rn, and $\\alpha$-grand-parent nuclei $^{201,203,205}$Ra. The polonium beams are produced with a UC$_{\\textrm{x}}$ target and using the RILIS.

  17. CdZnTe background measurements at balloon altitudes with PoRTIA

    International Nuclear Information System (INIS)

    Parsons, A.; Barthelmy, S.; Bartlett, L.; Gehrels, N.; Naya, J.; Stahle, C.M.; Tueller, J.; Teegarden, B.

    2004-01-01

    Measurements of the CdZnTe internal background at balloon altitudes are essential to determine which physical processes make the most important background contributions. We present results from CdZnTe background measurements made by PoRTIA, a small CdZnTe balloon instrument that was flown three times in three different shielding configurations. PoRTIA was passively shielded during its first flight from Palestine, Texas and actively shielded as a piggyback instrument on the GRIS balloon experiment during its second and third flights from Alice Springs, Australia, using the thick GRIS NaI anticoincidence shield. A significant CdZnTe background reduction was achieved during the third flight with PoRTIA placed completely inside the GRIS shield and blocking crystal, and thus completely surrounded by 15 cm of NaI. A unique balloon altitude background data set is provided by CdZnTe and Ge detectors simultaneously surrounded by the same thick anticoincidence shield; the presence of a single coaxial Ge detector inside the shield next to PoRTIA allowed a measurement of the ambient neutron flux inside the shield throughout the flight. These neutrons interact with the detector material to produce isomeric states of the Cd, Zn, and Te nuclei that radiatively decay; calculations are presented to determine the relative contribution of these decays to the fully shielded CdZnTe background measured by PoRTIA

  18. Measurement of very forward neutron energy spectra for 7 TeV proton--proton collisions at the Large Hadron Collider

    CERN Document Server

    Adriani, O.; Bonechi, L.; Bongi, M.; Castellini, G.; D'Alessandro, R.; Del Prete, M.; Haguenauer, M.; Itow, Y.; Kasahara, K.; Kawade, K.; Makino, Y.; Masuda, K.; Matsubayashi, E.; Menjo, H.; Mitsuka, G.; Muraki, Y.; Okuno, Y.; Papini, P.; Perrot, A-L.; Ricciarini, S.; Sako, T.; Sakurai, N.; Sugiura, Y.; Suzuki, T.; Tamura, T.; Tiberio, A.; Torii, S.; Tricomi, A.; Turner, W.C.; Zhou, Q.D.

    2015-01-01

    The Large Hadron Collider forward (LHCf) experiment is designed to use the LHC to verify the hadronic-interaction models used in cosmic-ray physics. Forward baryon production is one of the crucial points to understand the development of cosmic-ray showers. We report the neutron-energy spectra for LHC $\\sqrt{s}$ = 7 TeV proton--proton collisions with the pseudo-rapidity $\\eta$ ranging from 8.81 to 8.99, from 8.99 to 9.22, and from 10.76 to infinity. The measured energy spectra obtained from the two independent calorimeters of Arm1 and Arm2 show the same characteristic feature before unfolding the difference in the detector responses. We unfolded the measured spectra by using the multidimensional unfolding method based on Bayesian theory, and the unfolded spectra were compared with current hadronic-interaction models. The QGSJET II-03 model predicts a high neutron production rate at the highest pseudo-rapidity range similar to our results and the DPMJET 3.04 model describes our results well at the lower pseudo-...

  19. Design and construction of the equipment and obtention process of TeO{sub 2} for the {sup 131} I production; Diseno y construccion del equipo y proceso de obtencion de TeO{sub 2} para la produccion de {sup 131} I

    Energy Technology Data Exchange (ETDEWEB)

    Alanis M, J. [ININ, Departamento de Materiales Radiactivos, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2000-09-15

    This project was carried out in the National Institute of Nuclear Research, Nuclear Center of Mexico (ININ), with the name 'A New Method to Obtain {sup 131}I by Neutron Irradiation of TeO{sub 2} and it Dry Distillation'. This work establishes the optimal parameters to produce {sup 131}I by neutron irradiation and foundry of TeO{sub 2} sinterized. The TeO{sub 2} of high purity was produced adding HNO{sub 3} to the metallic tellurium (Merck 8100) and heating several samples to different temperatures until dryness in presence of an air current. The optimal conditions of temperature and reaction velocity were obtained, as well as of drying and sintering, to obtain TeO{sub 2} crystals with high purity able to retain the {sup 131}I produced by the radioactive decay. After drying and purified by the heating, the TeO{sub 2} was sinterized, applying a next temperature to it melting point by few minutes, enough to create cavities in the middle of it crystalline structure, where the {sup 131}I in gas form produced by the decay of the {sup 131}Te it is retained, one time that the TeO{sub 2} is bombarded with thermal neutrons in the nuclear reactor. Then, the reactions {sup 130}Te(n, {gamma}){sup 131}Te{sup m} (t{sub 1/2} = 30 h) and {sup 130}Te(n, {gamma}){sup 131}Te (t{sub 1/2} = 24.8 m) with an optimal irradiation time of 2.5 h. (Author)

  20. Scaling neutron absorbed dose distributions from one medium to another

    International Nuclear Information System (INIS)

    Awschalom, M.; Rosenberg, I.; Ten Haken, R.K.

    1983-01-01

    Central axis depth dose (CADD) and off-axis absorbed dose ratio (OAR) measurements were made in water, muscle and whole skeletal bone tissue-equivalent (TE) solutions, mineral oil, and glycerin with a clinical neutron therapy beam. These measurements show that, for a given neutron beam quality and field size, there is a universal CADD distribution at infinity if the depth in the phantom is expressed in terms of appropriate scaling lengths. These are essentially the kerma-weighted neutron mean free paths in the media. The method used in ICRU Report No. 26 to scale the CADD by the ratio of the densities is shown to give incorrect results. The OARs measured in different media at depths proportional to the respective mean free paths were also found to be independent of the media to a good approximation. Therefore, neutron beam CADDs and OARs may be measured in either TE solution (USA practice) or water (European practice), and having determined the respective scaling lengths, all measurements may be scaled from one medium to any other. It is recommended that for general treatment planning purposes, scaling be made to TE muscle with a density of 1.04 g cm -3 , since this value represents muscle and other soft tissues better than TE solution of density 1.07 g cm -3 . For such a transformation, relative measurements made in water are found to require very small corrections. Hence, it is further recommended that relative CADD and OAR measurements be performed in water because of its universality and convenience. Finally, a table of calculated scaling lengths is given for various neutron energy spectra and for various tissues and materials of practical importance in neutron dosimetry

  1. Neutron detection with cryogenics and semiconductors

    International Nuclear Information System (INIS)

    Bell, Zane W.; Carpenter, D.A.; Cristy, S.S.; Lamberti, V.E.; Burger, Arnold; Woodfield, Brian F.; Niedermayr, Thomas; Dragos Hau, I.; Labov, Simon E.; Friedrich, Stephan; Geoffrey West, W.; Pohl, Kenneth R.; Berg, Lodewijk van den

    2005-01-01

    The common methods of neutron detection are reviewed with special attention paid to the application of cryogenics and semiconductors to the problem. The authors' work with LiF- and boron-based cryogenic instruments is described as well as the use of CdTe and HgI 2 for direct detection of neutrons. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Rotation-aligned coupling and axial asymmetry in the neutron deficient lanthanum nuclei. Progress report, May 15, 1975--May 14, 1976

    International Nuclear Information System (INIS)

    Zganjar, E.F.

    1976-01-01

    The work on the neutron deficient nuclei in the Au region was brought nearer to completion, and systems necessary to extend the investigation to the La nuclei were developed. Twelve reports, including five journals articles, were generated during the reporting period, and the principal investigator received invitations to two international conferences. The LSU nuclear spectroscopy group was given a good deal of support and added strength (by the Department of Physics and Astronomy) through the addition of a nuclear structure theorist and a departmentally sponsored postdoctoral position

  3. CdZnTe detectors for gamma-ray Burst ArcSecond Imaging and Spectroscopy (BASIS)

    International Nuclear Information System (INIS)

    Stahle, C.M.; Palmer, D.; Bartlett, L.M.; Parsons, A.; Shi Zhiqing; Lisse, C.M.; Sappington, C.; Cao, N.; Shu, P.; Gehrels, N.; Teegarden, B.; Birsa, F.; Singh, S.; Odom, J.; Hanchak, C.; Tueller, J.; Barthelmy, S.; Krizmanic, J.; Barbier, L.

    1996-01-01

    A CdZnTe detector array is being developed for the proposed gamma-ray Burst ArcSecond Imaging and Spectroscopy (BASIS) spaceflight mission to accurately locate gamma-ray bursts, determine their distance scale, and measure the physical characteristics of the emission region. Two-dimensional strip detectors with 100 μm pitch have been fabricated and wire bonded to readout electronics to demonstrate the ability to localize 60 and 122 keV gamma-rays to less than 100 μm. Radiation damage studies on a CdZnTe detector exposed to MeV neutrons showed a small amount of activation but no detector performance degradation for fluences up to 10 10 neutrons/cm 2 . A 1 x 1 in. CdZnTe detector has also been flown on a balloon payload at 115 000 ft in order to measure the CdZnTe background rates. (orig.)

  4. Neutronic density perturbation by probes

    International Nuclear Information System (INIS)

    Vigon, M. A.; Diez, L.

    1956-01-01

    The introduction of absorbent materials of neutrons in diffuser media, produces local disturbances of neutronic density. The disturbance depends especially on the nature and size of the absorbent. Approximated equations which relates te disturbance and the distance to the absorbent in the case of thin disks have been drawn. The experimental comprobation has been carried out in two especial cases. In both cases the experimental results are in agreement with the calculated values from these equations. (Author)

  5. Yields of the rare-earth neutron-deficient isotopes in the reactions of Mo isotopes with 40Ca ions

    International Nuclear Information System (INIS)

    Adam, J.; Chaloun, P.; Gangrskij, Yu.P.

    1999-01-01

    The results of the joint Russian-Chinese experiment on the measurements of the reaction cross sections of the rare-earth neutron-deficient isotopes production and the study of their decay scheme are presented. The studied nuclides were obtained in the reactions 92 Mo + 40 Ca and 97 Mo + 40 Ca on the 4-meter cyclotron of the Flerov Laboratory of Nuclear Reactions, JINR. The recoil nuclei were stopped in the inert gas and transported by the gas flow to the detectors. The single and coincidence spectra of γ-, x-rays and delayed protons were measured. The enhanced yield of the reactions with the charge particle evaporation was observed

  6. Mass measurement of cooled neutron-deficient bismuth projectile fragments with time-resolved Schottky mass spectrometry at the FRS-ESR facility

    Energy Technology Data Exchange (ETDEWEB)

    Litvinov, Yu.A.; Geissel, H. [Giessen Univ. (Germany); Radon, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (DE)] [and others

    2005-06-01

    Masses of 582 neutron-deficient nuclides (30{<=}Z{<=}85) were measured with time-resolved Schottky mass spectrometry at the FRS-ESR facility at GSI, 117 were used for calibration. The masses of 71 nuclides were obtained for the first time. A typical mass accuracy of 30 {mu}u was achieved. These data have entered the latest atomic mass evaluation. The mass determination of about 140 additional nuclides was possible via known energies (Q-values) of {alpha}-, {beta}-, or proton decays. The obtained results are compared with the results of other measurements. (orig.)

  7. Syntheses, crystal structures, and characterization of two new Tl{sup +}-Cu{sup 2+}-Te{sup 6+} oxides: Tl{sub 4}CuTeO{sub 6} and Tl{sub 6}CuTe{sub 2}O{sub 10}

    Energy Technology Data Exchange (ETDEWEB)

    Yeon, Jeongho; Kim, Sang-Hwan [Department of Chemistry, University of Houston, 136 Fleming Building, Houston, TX 77204-5003 (United States); Green, Mark A. [Department of Materials Science and Engineering, University of Maryland, College Park, MD, 20742-2115 and NIST Center for Neutron Research, National Institute of Standard and Technology, 100 Bureau Drive, Gaithersburg, MD 20899-6103 (United States); Bhatti, Kanwal Preet; Leighton, C. [Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455-0132 (United States); Shiv Halasyamani, P., E-mail: psh@uh.edu [Department of Chemistry, University of Houston, 136 Fleming Building, Houston, TX 77204-5003 (United States)

    2012-12-15

    Crystals and polycrystalline powders of two new oxide materials, Tl{sub 4}CuTeO{sub 6} and Tl{sub 6}CuTe{sub 2}O{sub 10}, have been synthesized by hydrothermal and solid-state methods. The materials were structurally characterized by single-crystal X-ray diffraction. Tl{sub 4}CuTeO{sub 6} and Tl{sub 6}CuTe{sub 2}O{sub 10} exhibit one dimensional anionic slabs of [CuTeO{sub 6}]{sup 4-} and [CuTe{sub 2}O{sub 10}]{sup 6-}, respectively. Common to both slabs is the occurrence of Cu{sup 2+}O{sub 4} distorted squares and Te{sup 6+}O{sub 6} octahedra. The slabs are separated by Tl{sup +} cations. For Tl{sub 4}CuTeO{sub 6}, magnetic measurements indicate a maximum at {approx}8 K in the temperature dependence of the susceptibility. Low temperature neutron diffraction data confirm no long-range magnetic ordering occurs and the susceptibility was adequately accounted for by fits to a Heisenberg alternating chain model. For Tl{sub 6}CuTe{sub 2}O{sub 10} on the other hand, magnetic measurements revealed paramagnetism with no evidence of long-range magnetic ordering. Infrared, UV-vis spectra, thermogravimetric, and differential thermal analyses are also reported. Crystal data: Tl{sub 4}CuTeO{sub 6}, Triclinic, space group P-1 (No. 2), a=5.8629(8) A, b=8.7848(11) A, c=9.2572(12) A, {alpha}=66.0460(10), {beta}=74.2010(10), {gamma}=79.254(2), V=417.70(9) A{sup 3}, and Z=2; Tl{sub 6}CuTe{sub 2}O{sub 10}, orthorhombic, space group Pnma (No. 62), a=10.8628(6) A, b=11.4962(7) A, c=10.7238(6) A, V=1339.20(13) A{sup 3}, and Z=4. - Graphical Abstract: Two new oxide materials, Tl{sub 4}CuTeO{sub 6} and Tl{sub 6}CuTe{sub 2}O{sub 10}, have been synthesized and characterized. The materials exhibit one dimensional crystal structures consisting of CuO{sub 4} and TeO{sub 6} polyhedra. Highlights: Black-Right-Pointing-Pointer Two New Tl-Te-Cu-oxides have been synthesized and structurally characterized. Black-Right-Pointing-Pointer For Tl{sub 4}CuTeO{sub 6}, magnetic measurements indicate a

  8. Coulomb excitation of $^{182-184}$ Hg: Shape coexistence in the neutron-deficient lead region

    CERN Multimedia

    We put forward a study of the interplay between individual nucleon behavior and collective degrees of freedom in the nucleus, as manifested in shape coexistence in the neutron-deficient lead region. As a first step of this experimental campaign, we propose to perform Coulomb excitation on light mercury isotopes to probe their excited states and determine transitional and diagonal E2 matrix elements, especially reducing the current uncertainties. The results from previous Coulomb excitation measurements in this mass region performed with 2.85 MeV/u beams from REX-ISOLDE have shown the feasibility of these experiments. Based on our past experience and the results obtained, we propose a detailed study of the $^{182-184}$Hg nuclei, that exhibit a pronounced mixing between 2 low-lying excited states of apparently different deformation character, using the higher energy beams from HIE-ISOLDE which are crucial to reach our goal. The higher beam energy should result in an increased sensitivity with respect to the qua...

  9. Identification of excited states in 167Os and 168Os: shape coexistence at extreme neutron deficiency

    International Nuclear Information System (INIS)

    Joss, D.T.; King, S.L.; Page, R.D.; Simpson, J.; Keenan, A.; Amzal, N.; Baeck, T.; Bentley, M.A.; Cederwall, B.; Cocks, J.F.C.; Cullen, D.M.; Greenlees, P.T.; Helariutta, K.; Jones, P.M.; Julin, R.; Juutinen, S.; Kankaanpaeae, H.; Kettunen, H.; Kuusiniemi, P.; Leino, M.; Muikku, M.; Savelius, A.; Uusitalo, J.; Williams, S.J.

    2001-01-01

    Excited states in the very neutron-deficient isotopes 167 Os and 168 Os have been observed using the reaction 112 Sn( 58 Ni, 2pxn). The JUROSPHERE γ-ray spectrometer array was used in conjunction with the RITU gas-filled recoil separator to collect prompt γ radiation in coincidence with recoils implanted in a silicon strip detector located at the focal plane of RITU. Using a selective recoil decay tagging technique it has been possible to unambiguously assign γ-ray transitions to 167 Os and 168 Os through the characteristic α radioactivity of these nuclides. The high-spin structure of the bands is discussed in terms of quasiparticle configurations within the framework of the cranked shell model. The role of shape coexistence in 168 Os is examined with phenomenological three-band mixing calculations

  10. Phase diagrams of ZnTe-HgTe-Te and ZnTe-CdTe-HgTe-Te systems

    International Nuclear Information System (INIS)

    Andrukhiv, A.M.; Litvak, A.M.; Mironov, K.E.

    1992-01-01

    ZnTe-HgTe-Te system liquidus surface is investigated and solid solution layers are produced in this system by the method of liquid-phase epitaxy (LPE). The theoretical analysis of experimental and theoretical data allows to calculate the diagram of ZnTe-CdTe-HgTe-Te system fusibility. A significant effect of elastic stresses of the epitaxial layer, grown on CdTe substrate, on the process of LPE of solid solutions is established

  11. Heavy neutron-deficient radioactive beams: fission studies and fragment distributions

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, K.H.; Benlliure, J.; Heinz, A.; Voss, B. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Boeckstiegel, C.; Grewe, A.; Steinhaeuser, S.; Clerc, H.G.; Jong, M. de; Junghans, A.R.; Mueller, J. [Technische Hochschule Darmstadt (Germany). Inst. fuer Kernphysik; Pfuetzner, M. [Warsaw Univ. (Poland). Inst. of Experimental Physics

    1998-02-01

    The secondary-beam facility of GSI Darmstadt was used to study the fission process of short-lived radioactive nuclei. Relativistic secondary projectiles were produced by fragmentation of a 1 A GeV {sup 238}U primary beam and identified in nuclear charge and mass number. Their production cross sections were determined, and the fission competition in the statistical deexcitation was deduced for long isotopical chains. New results on the enhancement of the nuclear level density in spherical and deformed nuclei due to collective rotational and vibrational excitations were obtained. Using these reaction products as secondary beams, the dipole giant resonance was excited by electromagnetic interactions in a secondary lead target, and fission from excitation energies around 11 MeV was induced. The fission fragments were identified in nuclear charge, and their velocity vectors were determined. Elemental yields and total kinetic energies have been determined for a number of neutron-deficient actinides and preactinides which were not accessible with conventional techniques. The characteristics of multimodal fission of nuclei around {sup 226}Th were systematically investigated and related to the influence of shell effects on the potential energy and on the level density between fission barrier and scission. A systematic view on the large number of elemental yields measured gave rise to a new interpretation of the enhanced production of even elements in nuclear fission and allowed for a new understanding of pair breaking in large-scale collective motion. (orig.)

  12. Recent Re-Measurement of Neutron and Gamma-Ray Spectra 1080 Meters from the APRD (Army Pulse Radiation Division) Critical Facility,

    Science.gov (United States)

    1984-01-01

    TISSUE-EQUIVALENT ION CHAMBER GM - GEIGER-MUELLER COUNTER TE-GM - DIFFERENCE BETWEEN TE AND GM DATA MICRODOSE - MICRODOSIMETRY USING 0.5" ROSSI COUNTER...KERMA 4.26+8 1979 APRO NE-213+PR NEUTRON KERMA 4.26+8 1979 WWD NE-213 NEUTRON KERMA 3.10+8 > 550 KEV 1980 DREO MICRODOSE NEUTRON KERMA 4.32+8 1979...APRD GM GAMMA KERMA 3.86+7 1979 WWD NE-213 GAMMA KERMA 4.34+7 > 450 KEV 1980 DREO MICRODOSE GAMMA KERMA 3.90+7 76 1979 APRD TE TOTAL KERMA 4.50+8 50 c.c

  13. Neutron star evolution and emission

    Science.gov (United States)

    Epstein, R. I.; Edwards, B. C.; Haines, T. J.

    1997-01-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors investigated the evolution and radiation characteristics of individual neutron stars and stellar systems. The work concentrated on phenomena where new techniques and observations are dramatically enlarging the understanding of stellar phenomena. Part of this project was a study of x-ray and gamma-ray emission from neutron stars and other compact objects. This effort included calculating the thermal x-ray emission from young neutron stars, deriving the radio and gamma-ray emission from active pulsars and modeling intense gamma-ray bursts in distant galaxies. They also measured periodic optical and infrared fluctuations from rotating neutron stars and search for high-energy TeV gamma rays from discrete celestial sources.

  14. Resolution of the crystal structure of the deficient perovskite LaNiO2.5 from neutron powder diffraction data

    International Nuclear Information System (INIS)

    Alonso, J.A.; Martinez-Lope, M.J.

    1996-01-01

    The oxygen-deficient perovskite LaNiO 2.5 has been prepared by controlled reduction of LaNiO 3 with Zr metal. The XRD pattern could be indexed in a monoclinic unit-cell with dimensions a 0 xa 0 xa 0 (a 0 : lattice parameter of the ideal cubic perovskite). The indexing of the neutron powder diffraction pattern needed a doubled cell to account for the superstructure reflections originated by the oxygen vacancy ordering and the tilting of the Ni coordination polyhedra. The structure was solved and refined from the neutron powder data. The oxygen vacancies are ordered in such a way that square planar NiO 4 and NiO 6 octahedra alternate in the ab plane along the [110] direction. Both kinds of Ni polyhedra are fairly distorted and tilted in order to optimize the La-O distances, giving rise to a highly strained structure of metastable character. In fact, the compound readily takes oxygen, above 175 C in air, to give the much more stable LaNiO 3 perovskite. (orig.)

  15. Estimates of neutron fluence for the SDC detector

    International Nuclear Information System (INIS)

    Job, P.K.; Price, L.E.; Handler, T.; Gabriel, T.A.

    1994-01-01

    The high energy and high luminosity of SSC cause radiation problems to detectors. Almost all the radiation in the SDC detector comes from the 20 TeV on 20 TeV pp collisions. The design luminosity corresponds to 10 8 collisions per second. This luminosity is maintained for 10 7 seconds (one SSC year). It is important to know the radiation fields experienced by the tracking volume, calorimeter, electronics and the phototubes. The loss of light due to the radiation damage to the scintillators can adversely affect the physics performance of the calorimeter. Studies have been carried out earlier to estimate the radiation dose in the SDC detector. In this note the authors use ISAJET in combination with CALOR89 to make an accurate prediction of neutron fluence at the various locations of the SDC detector. The low energy neutrons are important because they can produce radioactive nuclides in large quantities. In CALOR89 the low energy neutron fluence is accurately estimated by MORSE code

  16. Calorimetric and ionometric dosimetry for cyclotron produced fast neutrons

    International Nuclear Information System (INIS)

    McDonald, J.C.; Ma, I.C.; Laughlin, J.S.

    1977-01-01

    A portable tissue equivalent (TE) calorimeter, constructed of A-150 plastic, has been employed for the measurement of absorbed dose in two fast neutron fields produced by the 9 Be( 3 He,n) and 9 Be(d,n) interactions. A disc shaped ionization chamber has also been constructed of A-150 plastic and has a collecting volume geometrically equivalent to the calorimeter core (2 cm in diameter and 0.2 cm thick). A flow of methane compounded TE gas was maintained through the chamber at a rate of approximately 5 cc/min during the measurements. The ionization chamber was mounted within an irradiation enclosure which simulated the outer dimensions of the calorimeter housing. In this way, both detectors were placed at the same depth in TE plastic and each received approximately the same scattered radiation. The gamma-ray component of absorbed dose has been determined by the use of a miniature Geiger-Mueller dosimeter. It was found that the response sensitivity ratio for the TE ionization chamber in the two neutron fields relative to the 60 Co gamma-ray field, when normalized to the absorbed dose measured by the TE calorimeter, was approximately 1.07. Uncertainties in these calorimetric and ionometric methods for the measurements of the absorbed dose will be discussed along with measurements of the thermal defect for A-150 TE plastic

  17. Nuclear decay scheme studies of 30-h 131Te/sup m/, 25-min 131Te/sup g/, and 55.5-min 105Cd

    International Nuclear Information System (INIS)

    Jackson, S.V.

    1975-01-01

    High-resolution Ge(Li) detectors have been used to observe γ-ray singles and coincidence spectra of 30-h 11 / 2 - , /sup 131m/Te, 25-min 3 / 2 + , and 55.5-min 5 / 2 + 105 Cd. Sources of /sup 131m/Te and /sup 131g/Te were produced by neutron irradiation of enriched 130 Te metal, and, in the case of /sup 131m/Te, were chemically purified to remove the 131 I daughter. A total of 190 and 80 γ-rays are attributed to the decays of /sup 131m/Te and /sup 131g/Te, respectively; and 174 and 77 of these transitions have been placed in a 131 I level scheme involving 52 excited states. Absolute β group intensities were determined for the transitions to 131 I levels. Spin and parity assignments were made for all observed levels. The β feeding from the 11 / 2 - /sup 131m/Te to the 7 / 2 + 131 I ground state was determined to be (5.2 +- 3.0) percent (log ft = 10.5). The isomeric transition of 11 / 2 - /sup 131m/Te to 3 / 2 + /sup 131g/Te was determined to be (22.2 +- 1.6) percent. The 6-nsec isomer in 131 I at 1797 keV has been assigned as 15 / 2 - and interpreted as a πν 1 ν 2 three quasi-particle state. Sources of 105 Cd were produced via the 106 Cd(n,2n) reaction on enriched 106 CdO using 14 MeV neutrons. A total of 274 γ-rays are attributed to the decay of 105 Cd, and 248 of these have been placed in a 105 Ag level scheme involving 50 excited states. Absolute values for the β + /EC transition intensities to 105 Ag levels were determined. The β + /EC feeding from the 5 / 2 + 105 Cd to the 7 / 2 + 25.5-keV isomeric state in 105 Ag was determined to be (51.4 +- 4.0) percent (log ft = 5.4). The experimentally determined level structures of 131 I and 105 Cd are interpreted in terms of the shell model and core excitation considerations with emphasis placed on the core coupling model and the three-particle models. (U.S.)

  18. The TE coupled RELAP5/PANTHER/COBRA code package and methodology for integrated PWR accident analysis

    International Nuclear Information System (INIS)

    Schneidesch, Christophe R.; Zhang, Jinzhao; Ammirabile, Luca; Dalleur, Jean-Paul

    2006-01-01

    At Tractebel Engineering (TE), a dynamic coupling has been developed between the best estimate thermal hydraulics system code RELAP5 and the 3-dimensional neutronics code PANTHER via the transient analysis code linkage program TALINK. An interface between PANTHER and the subchannel core thermal-hydraulic analysis code COBRA 3C has been established for on-line calculation of the Departure from Nucleate Boiling Ratio (DNBR). In addition to the standard RELAP5-PANTHER coupling, the fully dynamic coupling of the RELAP5/PANTHER/COBRA3C-TE code package can be activated for evaluation purposes in which the PANTHER close-channel thermal-hydraulics module is replaced by the COBRA3C-TE with cross flow modelling and extended T-H flow conditions capabilities. The qualification of the RELAP5-PANTHER coupling demonstrated the robustness achieved by the combined 3-D neutron kinetics/system T-H code package for transient simulations. The coupled TE code package has been approved by the Belgian Safety Authorities and is used at TE for analyzing asymmetric PWR accidents with strong core-system interactions. In particular, the TE coupled code package was first used to develop a main steam line break in hot shutdown conditions (SLBHZP) accident analysis methodology based on the TE deterministic bounding approach. This methodology has been reviewed and accepted by the Belgian Safety Authorities for specific applications. Those specific applications are related to the power up-rate and steam generator replacement project of the Doel 2 plant or to the Tihange-3 SLB accident re-analysis. A coupled feedwater line break (FLB) accident analysis methodology is currently being reviewed for application approval. The results of coupled thermal-hydraulic and neutronic analysis of SLB and FLB show that there exist important margins in the traditional final safety analysis report (FSAR) accident analysis. Those margins can be used to increase the operational flexibility of the plants. Moreover, the

  19. The TE coupled RELAP5/PANTHER/COBRA code package and methodology for integrated PWR accident analysis

    Energy Technology Data Exchange (ETDEWEB)

    Schneidesch, Christophe R.; Zhang, Jinzhao; Ammirabile, Luca; Dalleur, Jean-Paul [Suez-Tractebel Engineering, Avenue Ariane 7, B-1200 Brussels (Belgium)

    2006-07-01

    At Tractebel Engineering (TE), a dynamic coupling has been developed between the best estimate thermal hydraulics system code RELAP5 and the 3-dimensional neutronics code PANTHER via the transient analysis code linkage program TALINK. An interface between PANTHER and the subchannel core thermal-hydraulic analysis code COBRA 3C has been established for on-line calculation of the Departure from Nucleate Boiling Ratio (DNBR). In addition to the standard RELAP5-PANTHER coupling, the fully dynamic coupling of the RELAP5/PANTHER/COBRA3C-TE code package can be activated for evaluation purposes in which the PANTHER close-channel thermal-hydraulics module is replaced by the COBRA3C-TE with cross flow modelling and extended T-H flow conditions capabilities. The qualification of the RELAP5-PANTHER coupling demonstrated the robustness achieved by the combined 3-D neutron kinetics/system T-H code package for transient simulations. The coupled TE code package has been approved by the Belgian Safety Authorities and is used at TE for analyzing asymmetric PWR accidents with strong core-system interactions. In particular, the TE coupled code package was first used to develop a main steam line break in hot shutdown conditions (SLBHZP) accident analysis methodology based on the TE deterministic bounding approach. This methodology has been reviewed and accepted by the Belgian Safety Authorities for specific applications. Those specific applications are related to the power up-rate and steam generator replacement project of the Doel 2 plant or to the Tihange-3 SLB accident re-analysis. A coupled feedwater line break (FLB) accident analysis methodology is currently being reviewed for application approval. The results of coupled thermal-hydraulic and neutronic analysis of SLB and FLB show that there exist important margins in the traditional final safety analysis report (FSAR) accident analysis. Those margins can be used to increase the operational flexibility of the plants. Moreover, the

  20. Phonon spectra in the parent superconducting iron-tuned telluride F e1 +xTe from inelastic neutron scattering and ab initio calculations

    Science.gov (United States)

    Zbiri, Mohamed; Viennois, Romain

    2017-10-01

    We report inelastic neutron scattering measurements of phonon spectra in the parent superconductor iron-tuned chalcogenide F e1 +xTe for two different x contents (x ≤0.11 ) using neutron time-of-flight technique. Thermal neutron spectroscopy allowed the collection of the low-temperature Stokes spectra over an extended Q range at 2, 40, and 120 K, hence covering both the magnetic monoclinic and the paramagnetic tetragonal phases, whereas cold neutrons allowed the measurement of high-resolution anti-Stokes spectra at 140, 220, and 300 K, thus covering the tetragonal phase. Our results evidence a spin-phonon coupling behavior towards the observed noticeable temperature-dependent change of the Stokes spectra across the transition temperatures. On the other hand, the anti-Stokes spectra reveal a pronounced hardening of the low-energy, acoustic region of the phonon spectrum upon heating, indicating a strong anharmonicity and a subtle dependence of phonons on structural evolution within the tetragonal phase. Experimental results are accompanied by ab initio calculations of phonon spectra of the tetragonal stoichiometric phase for a comparison with the high-resolution anti-Stokes spectra. Calculations included different density functional methods. Spin polarization and van der Waals interaction were either considered or neglected, individually or concomitantly, in order to study their respective effect on lattice dynamics description. Our results suggest that including van der Waals interaction has only a slight effect on phonon dynamics; however, phonon spectra are better described when spin polarization is included in a cooperative way with van der Waals interactions.

  1. Single-Particle Structure of Neutron-Rich Nuclei

    International Nuclear Information System (INIS)

    Cizewski, Jolie; Jones, K.L.; Thomas, J.S.; Bardayan, Daniel W.; Blackmon, Jeff C.; Gross, Carl J.; Liang, J. Felix; Shapira, Dan; Smith, Michael Scott; Stracener, Daniel W.; Kozub, R.L.; Nesaraja, Caroline D.; Greife, U.; Livesay, Jake; Ma, Zhanwen

    2004-01-01

    Neutron transfer (d,p) reactions have been measured with rare isotope beams of 132Sn, 130Sn and 134Te accelerated to ∼4.5 MeV/u interacting with CD2 targets. Reaction protons were detected in an early implementation of the ORRUBA array of position-sensitive silicon strip detectors. Neutron excitations in the 2f7/2, 3p3/2, 3p1/2 and 2f5/2 orbitals were populated.

  2. Neutron Stars and NuSTAR

    Science.gov (United States)

    Bhalerao, Varun

    2012-05-01

    My thesis centers around the study of neutron stars, especially those in massive binary systems. To this end, it has two distinct components: the observational study of neutron stars in massive binaries with a goal of measuring neutron star masses and participation in NuSTAR, the first imaging hard X-ray mission, one that is extremely well suited to the study of massive binaries and compact objects in our Galaxy. The Nuclear Spectroscopic Telescope Array (NuSTAR) is a NASA Small Explorer mission that will carry the first focusing high energy X-ray telescope to orbit. NuSTAR has an order-of-magnitude better angular resolution and has two orders of magnitude higher sensitivity than any currently orbiting hard X-ray telescope. I worked to develop, calibrate, and test CdZnTe detectors for NuSTAR. I describe the CdZnTe detectors in comprehensive detail here - from readout procedures to data analysis. Detailed calibration of detectors is necessary for analyzing astrophysical source data obtained by the NuSTAR. I discuss the design and implementation of an automated setup for calibrating flight detectors, followed by calibration procedures and results. Neutron stars are an excellent probe of fundamental physics. The maximum mass of a neutron star can put stringent constraints on the equation of state of matter at extreme pressures and densities. From an astrophysical perspective, there are several open questions in our understanding of neutron stars. What are the birth masses of neutron stars? How do they change in binary evolution? Are there multiple mechanisms for the formation of neutron stars? Measuring masses of neutron stars helps answer these questions. Neutron stars in high-mass X-ray binaries have masses close to their birth mass, providing an opportunity to disentangle the role of "nature" and "nurture" in the observed mass distributions. In 2006, masses had been measured for only six such objects, but this small sample showed the greatest diversity in masses

  3. Low energy E0 transitions in odd-mass nuclei of the neutron deficient 180 < A < 200 region

    International Nuclear Information System (INIS)

    Zganjar, E.F.; Kortelahti, M.O.; Wood, J.L.; Papanicolopulos, C.D.

    1987-01-01

    The region of neutron-deficient nuclei near Z = 82 and N = 104 provides the most extensive example of low-energy shape coexistence anywhere on the mass surface. It is shown that E0 and E0 admixed transitions may be used as a fingerprint to identify shape coexistence in odd-mass nuclei. It is also shown that all the known cases of low energy E0 and E0 admixed transitions in odd-mass nuclei occur where equally low-lying O + states occur in neighboring even-even nuclei. A discussion of these and other relevant data as well as suggestions for new studies which may help to clarify and, more importantly, quantify the connection between E0 transitions and shape coexistence are presented. 60 refs., 7 figs., 4 tabs

  4. Study of the Neutron Deficient Pb and Bi Isotopes by Simultaneous Atomic- and Nuclear-Spectroscopy

    CERN Multimedia

    Kessler, T

    2002-01-01

    We propose to study systematically nuclear properties of the neutron deficient lead $^{183-189}$Pb, $^{191g}$Pb, $^{193g}$Pb and bismuth isotopes $^{188-200}$Bi by atomic spectroscopy with the ISOLDE resonance ionisation laser ion source (RILIS) combined with simultaneous nuclear spectroscopy at the detection set-up. The main focus is the determination of the mean square charge radii of $^{183-190}$Pb and $^{188-193}$Bi from which the influence of low-lying intruder states should become obvious. Also the nuclear spin and magnetic moments of ground-states and long-lived isomers will be determined unambiguously through evaluation of the hyperfine structure, and new isomers could be discovered. The decay properties of these nuclei can be measured by $\\alpha$-$\\gamma$ and $\\beta$-$\\gamma$ spectroscopy. With this data at hand, possible shape transitions around mid-shell at N$\\sim$104 will be studied. This data is crucial for the direct test of nuclear theory in the context of intruder state influence (e.g. energy ...

  5. Crystal structure and magnetic properties of the Ba3TeCo3P2O14, Pb3TeCo3P2O14, and Pb3TeCo3V2O14 langasites

    DEFF Research Database (Denmark)

    Krizan, J.W.; de la Cruz, C.; Andersen, Niels Hessel

    2013-01-01

    We report the structural and magnetic characterizations of Ba3TeCo3P2O14, Pb3TeCo3P2O14, and Pb3TeCo3V2O14, compounds that are based on the mineral dugganite, which is isostructural to langasites. The magnetic part of the structure consists of layers of Co2+ triangles. Nuclear and magnetic...... structures were determined through a co-refinement of synchrotron and neutron powder diffraction data. In contrast to the undistorted P321 langasite structure of Ba3TeCo3P2O14, a complex structural distortion yielding a large supercell is found for both Pb3TeCo3P2O14 and Pb3TeCo3V2O14. Comparison...... of the three compounds studied along with the zinc analog Pb3TeZn3P2O14, also characterized here, suggests that the distortion is driven by Pb2+ lone pairs; as such, the Pb compounds crystallize in a pyroelectric space group, P2. Magnetic susceptibility, magnetization, and heat capacity measurements were...

  6. TeV Gamma Rays From Galactic Center Pulsars

    Energy Technology Data Exchange (ETDEWEB)

    Hooper, Dan [Fermilab; Cholis, Ilias [Johns Hopkins U.; Linden, Tim [Ohio State U., CCAPP

    2017-05-25

    Measurements of the nearby pulsars Geminga and B0656+14 by the HAWC and Milagro telescopes have revealed the presence of bright TeV-emitting halos surrounding these objects. If young and middle-aged pulsars near the Galactic Center transfer a similar fraction of their energy into TeV photons, then these sources could dominate the emission that is observed by HESS and other ground-based telescopes from the innermost ~10^2 parsecs of the Milky Way. In particular, both the spectral shape and the angular extent of this emission is consistent with TeV halos produced by a population of pulsars. The overall flux of this emission requires a birth rate of ~100-1000 neutron stars per Myr near the Galactic Center, in good agreement with recent estimates.

  7. Absolute on-line in-pile measurement of neutron fluxes using self-powered neutron detectors: Monte Carlo sensitivity calculations

    Energy Technology Data Exchange (ETDEWEB)

    Vermeeren, L. [SCK/CEN, B-2400 Mol (Belgium)

    2001-07-01

    Self-powered neutron detectors (SPND) are well suited to monitor continuously the neutronic operating conditions of driver fuel of research reactors and to follow its burnup evolution. This is of particular importance when advanced or new MTR fuel designs need to be qualified. We have developed a detailed MCNP-4B based Monte Carlo approach for the calculation of neutron sensitivities of SPNDs. Results for the neutron sensitivity of a Rh SPND are in excellent agreement with experimental data recently obtained at the BR2 research reactor. A critical comparison of the Monte Carlo results with results from standard analytical methods reveals an important deficiency of the analytical methods in the description of the electron transport efficiency. Our calculation method allows a reliable on-line determination of the absolute in-pile neutron flux. (author)

  8. Absolute on-line in-pile measurement of neutron fluxes using self-powered neutron detectors: Monte Carlo sensitivity calculations

    International Nuclear Information System (INIS)

    Vermeeren, L.

    2001-01-01

    Self-powered neutron detectors (SPND) are well suited to monitor continuously the neutronic operating conditions of driver fuel of research reactors and to follow its burnup evolution. This is of particular importance when advanced or new MTR fuel designs need to be qualified. We have developed a detailed MCNP-4B based Monte Carlo approach for the calculation of neutron sensitivities of SPNDs. Results for the neutron sensitivity of a Rh SPND are in excellent agreement with experimental data recently obtained at the BR2 research reactor. A critical comparison of the Monte Carlo results with results from standard analytical methods reveals an important deficiency of the analytical methods in the description of the electron transport efficiency. Our calculation method allows a reliable on-line determination of the absolute in-pile neutron flux. (author)

  9. Shape coexistence in neutron-deficient Hg isotopes studied via lifetime measurements in $^{184,186}$Hg and two-state mixing calculations

    CERN Document Server

    Gaffney, L P; Page, R.D.; Grahn, T.; Scheck, M.; Butler, P.A.; Bertone, P.F.; Bree, N.; Carroll, R.J.; Carpenter, M.P.; Chiara, C.J.; Dewald, A.; Filmer, F.; Fransen, C.; Huyse, M.; Janssens, R.V.F.; Joss, D.T.; Julin, R.; Kondev, F.G.; Nieminen, P.; Pakarinen, J.; Rigby, S.V.; Rother, W.; Van Duppen, P.; Watkins, H.V.; Wrzosek-Lipska, K.; Zhu, S.

    2014-01-01

    The neutron-deficient mercury isotopes, $^{184,186}$Hg, were studied with the Recoil Distance Doppler Shift (RDDS) method using the Gammasphere array and the K\\"oln Plunger device. The Differential Decay Curve Method (DDCM) was employed to determine the lifetimes of the yrast states in $^{184,186}$Hg. An improvement on previously measured values of yrast states up to $8^{+}$ is presented as well as first values for the $9_{3}$ state in $^{184}$Hg and $10^{+}$ state in $^{186}$Hg. $B(E2)$ values are calculated and compared to a two-state mixing model which utilizes the variable moment of inertia (VMI) model, allowing for extraction of spin-dependent mixing strengths and amplitudes.

  10. Method for manufacture of neutron absorbing articles

    International Nuclear Information System (INIS)

    Owens, D.

    1980-01-01

    A one-step curing method for the manufacture of a neutron absorbing article which comprises irreversibly curing, in desired article form, a form-retaining mixture of boron carbide particles, curable phenolic resin in solid state and in particula te form and a minor proportion of a liquid medium, which boils at a temperature below 200*c., at an elevated temperature so as to obtain bonding of the irreversibly cured phenolic polymer resulting to the boron carbide particles and production of the neutron absorbing article in desired form

  11. Thermal conductivity of beryllium under low temperature high dose neutron irradiation

    International Nuclear Information System (INIS)

    Chakin, V.P.; Latypov, R.N.; Suslov, D.N.; Kupriyanov, I.B.

    2004-01-01

    Thermal conductivity of compact beryllium of several Russian grades such as TE-400, TE-56, TE-30, TIP and DIP differing in the production technology, grain size and impurity content has been investigated. The thermal diffusivity of beryllium was measured on the disks in the initial and irradiated conditions using the pulse method in the range from room temperature to 200degC. The thermal conductivity was calculated using the table values for the beryllium thermal capacity. The specimens and beryllium neutron source fragments were irradiation in the SM reactor at 70degC and 200degC to a neutron fluence of (0.5-11.4)·10 22 cm -2 (E>0.1 MeV) and in the BOR-60 reactor at 400degC to 16·10 22 cm -2 (E>0.1MeV), respectively. The low-temperature irradiation leads to the drop decrease of the beryllium thermal conductivity and the effect depends on the irradiation parameters. The paper analyses the effect of irradiation parameters (temperature, neutron fluence), measurement temperature and structural factors on beryllium conductivity. The experiments have revealed that the short time post-irradiation annealing at high temperature results in partial reduction of the thermal conductivity of irradiated beryllium. (author)

  12. Mechanisms of fission neutron emission

    International Nuclear Information System (INIS)

    Maerten, H.

    1991-01-01

    The time evolution in fission is the starting point for discussing not only the main mechanism of fission neutron emission, the evaporation from fully accelerated fragments, but also possible secondary ones connected with dynamical features of nuclear fission. ''Asymptotic'' conditions as relevant for describing the particle release from highly excited, rapidly moving fragments are defined. Corresponding statistical model approaches to fission neutron emission, based on the adequate consideration of the intricate fragment occurrence probability, reproduce most of the experimental data. The remarkable influence of fission modes on neutron observables is analyzed in the framework of a macroscopic-microscopic scission point model consistent with energy conservation. Finally, chances and deficiencies for solving the mechanism puzzle are summarized. (author). 87 refs, 21 figs

  13. Uptakes of trace elements in Zn-deficient mice

    International Nuclear Information System (INIS)

    Ohyama, T.; Yanaga, M.; Yoshida, T.; Maetsu, H.; Suganuma, H.; Omori, T.

    2002-01-01

    A multitracer technique was used to obtain uptake rates of essential trace elements in various organs and tissues in Zn-deficient mice. A multitracer solution, containing more than 20 radioisotopes, was injected intraperitoneally into Zn-deficient state mice and control ones. Uptake rates of the radioisotopes were compared with concentrations of trace elements determined by instrumental neutron activation analysis (INAA) in order to study a specific metabolism of Zn and other essential trace elements, such as Mn, Co, Se, Rb, and Sr. The result suggests that Zn is supplied from bone to other organs and tissues and an increase in Co concentration in all organs and tissues depends on its chemical form, under the Z-deficient state. (author)

  14. Proton-neutron correlations in a broken-pair model

    International Nuclear Information System (INIS)

    Akkermans, J.N.L.

    1981-01-01

    In this thesis nuclear-structure calculations are reported which were performed with the broken-pair model. The model which is developed, is an extension of existing broken-pair models in so far that it includes both proton and neutron valence pairs. The relevant formalisms are presented. In contrast to the number-non-conserving model, a proton-neutron broken-pair model is well suited to study the correlations which are produced by the proton-neutron interaction. It is shown that the proton-neutron force has large matrix elements which mix the proton- with neutron broken-pair configurations. This occurs especially for Jsup(PI)=2 + and 3 - pairs. This property of the proton-neutron force is used to improve the spectra of single-closed shell nuclei, where particle-hole excitations of the closed shell are a special case of broken-pair configurations. Using Kr and Te isotopes it is demonstrated that the proton-neutron force gives rise to correlated pair structures, which remain remarkably constant with varying nucleon numbers. (Auth.)

  15. Decay pattern of the Pygmy Dipole Resonance in 130Te

    Science.gov (United States)

    Isaak, J.; Beller, J.; Fiori, E.; Krtička, M.; Löher, B.; Pietralla, N.; Romig, C.; Rusev, G.; Savran, D.; Scheck, M.; Silva, J.; Sonnabend, K.; Tonchev, A.; Tornow, W.; Weller, H.; Zweidinger, M.

    2014-03-01

    The electric dipole strength distribution in 130Te has been investigated using the method of Nuclear Resonance Fluorescence. The experiments were performed at the Darmstadt High Intensity Photon Setup using bremsstrahlung as photon source and at the High Intensity overrightarrow γ -Ray Source, where quasi-monochromatic and polarized photon beams are provided. Average decay properties of 130Te below the neutron separation energy are determined. Comparing the experimental data to the predictions of the statistical model indicate, that nuclear structure effects play an important role even at sufficiently high excitation energies. Preliminary results will be presented.

  16. Decay pattern of the Pygmy Dipole Resonance in 130Te

    Directory of Open Access Journals (Sweden)

    Isaak J.

    2014-03-01

    Full Text Available The electric dipole strength distribution in 130Te has been investigated using the method of Nuclear Resonance Fluorescence. The experiments were performed at the Darmstadt High Intensity Photon Setup using bremsstrahlung as photon source and at the High Intensity γ→$\\overrightarrow \\gamma $-Ray Source, where quasi-monochromatic and polarized photon beams are provided. Average decay properties of 130Te below the neutron separation energy are determined. Comparing the experimental data to the predictions of the statistical model indicate, that nuclear structure effects play an important role even at sufficiently high excitation energies. Preliminary results will be presented.

  17. Performance of the multiple target He/PbI sub 2 aerosol jet system for mass separation of neutron-deficient actinide isotopes

    CERN Document Server

    Ichikawa, S; Asai, M; Haba, H; Sakama, M; Kojima, Y; Shibata, M; Nagame, Y; Oura, Y; Kawade, K

    2002-01-01

    A multiple target He/PbI sub 2 aerosol jet system coupled with a thermal ion source was installed in the isotope separator on line (JAERI-ISOL) at the JAERI tandem accelerator facility. The neutron-deficient americium and curium isotopes produced in the sup 2 sup 3 sup 3 sup , sup 2 sup 3 sup 5 U( sup 6 Li, xn) and sup 2 sup 3 sup 7 Np( sup 6 Li, xn) reactions were successfully mass-separated and the overall efficiency including the ionization of Am atoms was evaluated to be 0.3-0.4%. The identification of a new isotope sup 2 sup 3 sup 7 Cm with the present system is reported.

  18. CdZnTe γ detector for deep inelastic neutron scattering on the VESUVIO spectrometer

    Science.gov (United States)

    Andreani, C.; D'Angelo, A.; Gorini, G.; Imberti, S.; Pietropaolo, A.; Rhodes, N. J.; Schooneveld, E. M.; Senesi, R.; Tardocchi, M.

    In this paper it is shown that solid-state cadmium-zinc-telluride (CZT) is a promising photon detector for neutron spectroscopy in a wide energy interval, ranging from thermal ( 25 meV) to epithermal ( 70 eV) neutron energies. In the present study two CZT detectors were tested as part of the inverse-geometry neutron spectrometer VESUVIO operating at the ISIS pulsed neutron source. The response of the CZT detector to photon emission from radiative neutron capture in 238U was determined by biparametric measurements of neutron time of flight and photon energy. The scattering response function F(y) from a Pb sample has been derived using both CZT and conventional 6Li-glass scintillator detectors. The former showed both an improved signal to background ratio and higher efficiency as compared to 6Li glass, allowing us to measure F(y) up to the fourth 238U absorption energy (Er=66.02 eV). Due to the small size of CZT detectors, their use is envisaged in arrays, with high spatial resolution, for neutron-scattering studies at high energy (ω>1 eV) and low wavevector (q <10 Å-1) transfers.

  19. CdZnTe γ detector for deep inelastic neutron scattering on the VESUVIO spectrometer

    International Nuclear Information System (INIS)

    Andreani, C.; Pietropaolo, A.; Senesi, R.; D'Angelo, A.; Gorini, G.; Imberti, S.; Tardocchi, M.; Rhodes, N.J.; Schooneveld, E.M.

    2004-01-01

    In this paper it is shown that solid-state cadmium-zinc-telluride (CZT) is a promising photon detector for neutron spectroscopy in a wide energy interval, ranging from thermal (∝25 meV) to epithermal (∝70 eV) neutron energies. In the present study two CZT detectors were tested as part of the inverse-geometry neutron spectrometer VESUVIO operating at the ISIS pulsed neutron source. The response of the CZT detector to photon emission from radiative neutron capture in 238 U was determined by biparametric measurements of neutron time of flight and photon energy. The scattering response function F(y) from a Pb sample has been derived using both CZT and conventional 6 Li-glass scintillator detectors. The former showed both an improved signal to background ratio and higher efficiency as compared to 6 Li glass, allowing us to measure F(y) up to the fourth 238 U absorption energy (E r =66.02 eV). Due to the small size of CZT detectors, their use is envisaged in arrays, with high spatial resolution, for neutron-scattering studies at high energy (ℎω>1 eV) and low wavevector (q -1 ) transfers. (orig.)

  20. The progress of neutron induced prompt gamma analysis technique in 1988-2002

    International Nuclear Information System (INIS)

    Liu Yuren; Jing Shiwei

    2003-01-01

    The new development of the neutron induced prompt gamma-ray analysis (NIPGA) technology in 1988-2002 are described. The pulse fast-thermal neutron activation analysis method, which utilizes the inelastic reaction and capture reaction jointly is employed to measure the elemental content in the material more efficiently. The lifetime of the neutron generator is more than 10000 h and the capability of HPGe, TeZeCd and MCA (multi-channel analyser) reaches the high level. At the same time, Monte Carlo Library least-square method is used to solve the nonlinearity problem in the PGNAA (Prompt Gamma Neutron Activation Analysis)

  1. Fast neutron dosimetry. Progress report, July 1, 1979-June 30, 1980

    International Nuclear Information System (INIS)

    Attix, F.H.

    1980-01-01

    Progress is reported in: the development and testing of new gas mixtures more suitable for fast neutron dosimetry using the common A150-type Tissue-equivalent plastic ion chambers; comparison of photon doses determined with a graphite-walled proportional counter and with paired dosimeters irradiated by 14.8-MeV neutrons; a detector for the direct measurement of LET distributions from irradiation with fast neutrons; LET distributions from fast neutron irradiation of TE-plastic and graphite measured in a cylindrically symmetric geometry; progress in development of a tandem fast neutron and 60 Co gamma ray source irradiation facility; an approach to the correlation of cellular response with lineal energy; calculated and measured HTO atmospheric dispersion rates within meters of a release site; application of cavity theory to fast neutrons; and fast neutron dosimetry by thermally stimulated currents in Al 2 O 3

  2. Neutron dosimetry in boron neutron capture therapy

    International Nuclear Information System (INIS)

    Fairchild, R.G.; Miola, U.J.; Ettinger, K.V.

    1981-01-01

    The recent development of various borated compounds and the utilization of one of these (Na 2 B 12 H 11 SH) to treat brain tumors in clinical studies in Japan has renewed interest in neutron capture therapy. In these procedures thermal neutrons interact with 10 B in boron containing cells through the 10 B(n,α) 7 Li reaction producing charged particles with a maximum range of approx. 10μm in tissue. Borated analogs of chlorpromazine, porphyrin, thiouracil and deoxyuridine promise improved tumor uptake and blood clearance. The therapy beam from the Medical Research Reactor in Brookhaven contains neutrons from a modified and filtered fission spectrum and dosimetric consequences of the use of the above mentioned compounds in conjunction with thermal and epithermal fluxes are discussed in the paper. One of the important problems of radiation dosimetry in capture therapy is determination of the flux profile and, hence, the dose profile in the brain. This has been achieved by constructing a brain phantom made of TE plastic. The lyoluminescence technique provides a convenient way of monitoring the neutron flux distributions; the detectors for this purpose utilize 6 Li and 10 B compounds. Such compounds have been synthesized specially for the purpose of dosimetry of thermal and epithermal beams. In addition, standard lyoluminescent phosphors, like glutamine, could be used to determine the collisional component of the dose as well as the contribution of the 14 N(n,p) 14 C reaction. Measurements of thermal flux were compared with calculations and with measurements done with activation foils

  3. Analysis of a neutron scattering integral experiment on iron for neutron energies from 1 to 15 MeV

    International Nuclear Information System (INIS)

    Cramer, S.N.; Oblow, E.M.

    1976-11-01

    Monte Carlo calculations were made to analyze the results of an integral experiment with an iron sample to determine the adequacy of neutron scattering cross section data for iron. The experimental results analyzed included energy-dependent NE-213 detector count rates at a scattering angle of 90 deg and pulse-height spectra for scattered neutrons produced in an iron ring pulsed with a 1- to 20-MeV neutron source. The pulse-height data were unfolded to generate secondary neutron spectra at 90 deg as a function of incident neutron energy. Multigroup Monte Carlo calculations using the MORSE code and ENDF/B-IV cross sections were made to analyze all reported results. Discrepancies between calculated and measured responses were found for inelastic scattering reactions in the range from 1 to 4 MeV. These results were related to deficiencies in ENDF/B-IV iron cross section data

  4. Decay studies of new neutron deficient isotopes in the range of elements between gadolinium and lead

    CERN Document Server

    Hofmann, S; Faust, W; Guttner, K; Hessberger, F P; Münzenberg, G; Reisdorf, W; Schneider, J H R; Thuma, B

    1981-01-01

    Very neutron deficient isotopes below lead are produced with beams of /sup 58/Ni, /sup 92/Mo, and /sup 107/Ag accelerated by the linear accelerator UNILAC. After separation from the projectile beam by the velocity filter SHIP, the fusion products are implanted with their full recoil energy into an array of position-sensitive detectors. With a newly developed position and time correlation technique, parent daughter relationships, half lives and alpha branching ratios of a large number of isotopes are determined. Two new alpha emitting isomeric states are identified in /sup 155/Lu and /sup 156/Hf. The energies of the excited states are (1798+or-12) keV in /sup 155/Lu and (1977+18) keV in /sup 156/Hf, the half-lives are (2.60+or-0.07) ms and (444+or-17) mu s, respectively. Compared to the ground state transitions, a hindrance of 10/sup 5/ can be deduced for both transitions, possibly indicating orbital angular momenta of the order of 10 h(cross) for the alpha emitting states. The isomers are proposed to belong t...

  5. CdZnTe {gamma} detector for deep inelastic neutron scattering on the VESUVIO spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Andreani, C.; Pietropaolo, A.; Senesi, R. [Dipartimento di Fisica, Universita degli Studi di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133, Roma (Italy); Istituto Nazionale per la Fisica della Materia, UdR, Tor Vergata (Italy); D' Angelo, A. [Dipartimento di Fisica, Universita degli Studi di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133, Roma (Italy); Istituto Nazionale di Fisica Nucleare, Sezione, Roma II (Italy); Gorini, G.; Imberti, S.; Tardocchi, M. [Dipartimento di Fisica G. Occhialini, Universita degli Studi di Milano-Bicocca, Piazza della Scienza 3, 20126, Milano (Italy); Istituto Nazionale per la Fisica della Materia, UdR, Milano-Bicocca (Italy); Rhodes, N.J.; Schooneveld, E.M. [Isis Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, Oxfordshire (United Kingdom)

    2004-03-01

    In this paper it is shown that solid-state cadmium-zinc-telluride (CZT) is a promising photon detector for neutron spectroscopy in a wide energy interval, ranging from thermal ({proportional_to}25 meV) to epithermal ({proportional_to}70 eV) neutron energies. In the present study two CZT detectors were tested as part of the inverse-geometry neutron spectrometer VESUVIO operating at the ISIS pulsed neutron source. The response of the CZT detector to photon emission from radiative neutron capture in {sup 238}U was determined by biparametric measurements of neutron time of flight and photon energy. The scattering response function F(y) from a Pb sample has been derived using both CZT and conventional {sup 6}Li-glass scintillator detectors. The former showed both an improved signal to background ratio and higher efficiency as compared to {sup 6}Li glass, allowing us to measure F(y) up to the fourth {sup 238}U absorption energy (E{sub r}=66.02 eV). Due to the small size of CZT detectors, their use is envisaged in arrays, with high spatial resolution, for neutron-scattering studies at high energy ({Dirac_h}{omega}>1 eV) and low wavevector (q <10 A{sup -1}) transfers. (orig.)

  6. Determination of dose components in mixed gamma neutron fields by use of high pressure ionization chambers

    International Nuclear Information System (INIS)

    Golnik, N.; Pliszczynski, T.; Wysocka, A.; Zielczynski, M.

    1985-01-01

    The two ionization chamber method for determination of dose components in mixed γ-neutron field has been improved by increasing gas pressure in the chambers up to some milions pascals. Advantages of high pressure gas filling are the followings: 1) significant reduction of the ratio of neutron-to gamma sensitivity for the hydrogen-free chamber, 2) possibility of sensitivity correction for both chambers by application of appropriate voltage, 3) high sensitivity for small detectors. High-pressure, pen-like ionization chambers have been examined in fields of different neutron sources: a TE-chamber, filled with 0.2 MPa of quasi-TE-gas and a conductive PTFE chamber, filled with 3.1 MPa of CO 2 . The ratio of neutron-to-gamma sensitivity for the PTFE chamber, operated at electrical field strength below 100 V/cm, has not exceeded 0.01 for neutrons with energy below 8 MeV. Formula is presented for calculation of this ratio for any high-pressure, CO 2 -filled ionization chamber. Contribution of gamma component to total tissue dose in the field of typical neutron sources has been found to be 3 to 70%

  7. Improving the thermoelectric performance of metastable rock-salt GeTe-rich Ge-Sb-Te thin films through tuning of grain orientation and vacancies

    Energy Technology Data Exchange (ETDEWEB)

    Chen, I. Nan [Department of Physics, National Taiwan University, Taipei (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei (China); Chong, Cheong-Wei [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei (China); Center for Condensed Matter Sciences, National Taiwan University, Taipei (China); Wong, Deniz P.; Lyu, Liang-Ming; Chien, Wei-Lun; Anbalagan, Ramakrishnan; Aminzare, Masoud; Chen, Kuei-Hsien [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei (China); Chen, Yang-Fang [Department of Physics, National Taiwan University, Taipei (China); Chen, Li-Chyong [Center for Condensed Matter Sciences, National Taiwan University, Taipei (China)

    2016-12-15

    Phase-change memory materials such as the pseudobinary GeTe-Sb{sub 2}Te{sub 3} compounds have recently gained attention for their good thermoelectric properties, which can be used for power-generation/cooling applications. In this work, GeTe-rich Ge-Sb-Te thin films deposited using a radio-frequency magnetron sputtering method readily exhibit the metastable face-centered cubic (FCC) phase at room temperature. This is in stark contrast to its bulk form, which only transforms to its FCC phase after a transition temperature of around 350 C. Based on previous works, the FCC phase contributes to the superior thermoelectric properties of this material system. In this study, by decreasing the working deposition pressure, the preferred orientation of (200) plane is observed that translates to improved carrier mobility. Moreover, increasing the annealing temperature has been shown to decrease the carrier concentration due to Te deficiency, leading to a significant improvement in the Seebeck coefficient of the film. By combining these effects, an optimized thermoelectric power factor (21 μW/cm K{sup 2}) was obtained at an operating temperature of 350 C. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Neutron Interactions in the CUORE Neutrinoless Double Beta Decay Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Dolinski, Michelle Jean [Univ. of California, Berkeley, CA (United States)

    2008-10-01

    Neutrinoless double beta decay (0vDBD) is a lepton-number violating process that can occur only for a massive Majorana neutrino. The search for 0vDBD is currently the only practical experimental way to determine whether neutrinos are identical to their own antiparticles (Majorana neutrinos) or have distinct particle and anti-particle states (Dirac neutrinos). In addition, the observation of 0vDBD can provide information about the absolute mass scale of the neutrino. The Cuoricino experiment was a sensitive search for 0vDBD, as well as a proof of principle for the next generation experiment, CUORE. CUORE will search for 0vDBD of 130Te with a ton-scale array of unenriched TeO2 bolometers. By increasing mass and decreasing the background for 0vDBD, the half-life sensitivity of CUORE will be a factor of twenty better than that of Cuoricino. The site for both of these experiments is the Laboratori Nazionali del Gran Sasso, an underground laboratory with 3300 meters water equivalent rock overburden and a cosmic ray muon attenuation factor of 10-6. Because of the extreme low background requirements for CUORE, it is important that all potential sources of background in the 0vDBD peak region at 2530 keV are well understood. One potential source of background for CUORE comes from neutrons, which can be produced underground both by (α,n) reactions and by fast cosmic ray muon interactions. Preliminary simulations by the CUORE collaboration indicate that these backgrounds will be negligible for CUORE. However, in order to accurately simulate the expected neutron background, it is important to understand the cross sections for neutron interactions with detector materials. In order to help refine these simulations, I have measured the gamma-ray production cross sections for interactions of neutrons on the abundant stable isotopes of Te using the GEANIE detector array at the Los Alamos Neutron Science Center. In addition, I have used the GEANIE

  9. Empty sella syndrome associated with hormone deficiency in adults

    International Nuclear Information System (INIS)

    Oleaga, L.; Paja, M.; Goni, F.; Grande, J.; Grande, D.; Merino, M.; Delgado, A.

    1999-01-01

    The objective of this study was to correlate the magnetic resonance (MR) images in patients with hormone deficiencies with the clinical data and the hormonal status. We studied 11 cases ef empty sella with different peripheral pituitary deficiencies. Hormone levels were determined according to standard laboratory methods. All the patients underwent MR imaging. The studies were carried out with a 1 Tesla superconducting magnet, using the cranial cavity for transmission and reception. Segittal and coronal T1-weighted spin-echo sequences (TR/TE: 600/15 ms), axial T2-weighted spin-echo sequences (TR/TE: 3,500/19/93 ms) and gadolinium-enhanced (=.2 cc/kg body weight) sagital and coronal T1-weighted spin-echo sequences (TR/TE: 600/15 ms) were employed. Six of the patients presented partial or total hypopituitarism associated with the syndrome of inappropriate antidiuretic hormone secretion (SIADH); there was one case of panhypopituitarism without SIADH and four cases of primary hypothyroidism, there of which were associated with pituitary deficiency, MR imaging revealed five cases of partially empty sella with residual pituitary gland on the sella floor and six cases in which the sella was completely empty. This study also identified six cases of normally situated neurohypophysis, another four in which the neurohypophysis could not be identified and one case of ectopic neurohypophysis. MR imaging is the technique of choice in the study of abnormal hypothalamic-pituitary activity. Empty and partially empty sella should be included among the frequent causes of hypopituitarism, although there is no clear relationship between the degree of adenohypophyseal insufficiency and the degree of atrophy of this system as viewed in MR images. In some cases, this entity may be the radiological sign of a phase in the development of an autoimmune inflammatory process involving the pituitary gland. (Author) 16 refs

  10. Fast neutron dosimetry. Progress report, July 1, 1979-June 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Attix, F.H.

    1980-01-01

    Progress is reported in: the development and testing of new gas mixtures more suitable for fast neutron dosimetry using the common A150-type Tissue-equivalent plastic ion chambers; comparison of photon doses determined with a graphite-walled proportional counter and with paired dosimeters irradiated by 14.8-MeV neutrons; a detector for the direct measurement of LET distributions from irradiation with fast neutrons; LET distributions from fast neutron irradiation of TE-plastic and graphite measured in a cylindrically symmetric geometry; progress in development of a tandem fast neutron and /sup 60/Co gamma ray source irradiation facility; an approach to the correlation of cellular response with lineal energy; calculated and measured HTO atmospheric dispersion rates within meters of a release site; application of cavity theory to fast neutrons; and fast neutron dosimetry by thermally stimulated currents in Al/sub 2/O/sub 3/. (GHT)

  11. Scientific Design of the New Neutron Radiography Facility (SANRAD) at SAFARI-1 for South Africa

    Science.gov (United States)

    de Beer, F. C.; Gruenauer, F.; Radebe, J. M.; Modise, T.; Schillinger, B.

    The final scientific design for an upgraded neutron radiography/tomography facility at beam port no.2 of the SAFARI-1 nuclear research reactor has been performed through expert advice from Physics Consulting, FRMII in Germany and IPEN, Brazil. A need to upgrade the facility became apparent due to the identification of various deficiencies of the current SANRAD facility during an IAEA-sponsored expert mission of international scientists to Necsa, South Africa. A lack of adequate shielding that results in high neutron background on the beam port floor, a mismatch in the collimator aperture to the core that results in a high gradient in neutron flux on the imaging plane and due to a relative low L/D the quality of the radiographs are poor, are a number of deficiencies to name a few.The new design, based on results of Monte Carlo (MCNP-X) simulations of neutron- and gamma transport from the reactor core and through the new facility, is being outlined. The scientific design philosophy, neutron optics and imaging capabilities that include the utilization of fission neutrons, thermal neutrons, and gamma-rays emerging from the core of SAFARI-1 are discussed.

  12. Collinear laser spectroscopy on radioactive neutron-deficient lead and thallium isotopes

    International Nuclear Information System (INIS)

    Menges, R.

    1989-02-01

    The systematic study of the isotope shift in the neighbourhood of the closed shells was extended in this thesis to Z = 82. The elements lead and thallium were measured up to the mass 190 and 188 and the nuclear moments determined together with the change of the mean square charge radius. The accumulating of the recoil nuclei formed by heavy ion reactions in the bunched ion source of the GSI mass separator could be used in order to study the low-spin isomers with I = 2 of the neutron-deficient thallium isotopes up to A = 190. It is a clearly recognizable isomer shift against the I = 7 isomers shown which changes at A = 194 the sign. A phenomenon which also exists in the element mercury, but for which no sufficient explanation exists. The magnetic moments of the thallium isotopes complete the analysis of Ekstroem (1976) and confirm the choice of the sign of the magnetic moments of the I = 2 isomers. The application of the additivity rule to the odd-odd nuclei shows qualitatively good agreement with the experiment and confirms so the assignment of the configuration of the contributing nuclear states. The quadrupole moments show a slight oblate deformation of the 9/2 - intruder states. The moments of the lead isotopes show pronounced one-particle character and by this the nearly spherical shape of nuclei with closed proton shell. The deviation from the linear slope of the mean square radius of the lead isotopes onsetting at A = 194 cannot be explained by the mixing of the 0 1 + ground state with the deformed 0 2 + intruder state. The odd - even staggering and the buckling of the charge radii at the shell closure are very well reproduced by Hartree-Fock calculations which regard the 3- and 4-particle interactions in the nucleus. (orig.) [de

  13. Theory of neutron emission in fission

    International Nuclear Information System (INIS)

    Madland, D.G.

    1998-01-01

    A survey of theoretical representations of two of the observables in neutron emission in fission is given, namely, the prompt fission neutron spectrum N(E) and the average prompt neutron multiplicity bar ν p . Early representations of the two observables are presented and their deficiencies are discussed. This is followed by summaries and some examples of recent theoretical models for the calculation of these quantities. Emphasis is placed upon the predictability and accuracy of the recent models. In particular, the dependencies of N(E) and bar ν p upon the fissioning nucleus and its excitation energy are treated in detail for the Los Alamos model. Recent work in the calculation of the prompt fission neutron spectrum matrix N(E, E n ), where E n is the energy of the neutron inducing fission, is then discussed. Concluding remarks address the current status of the ability to calculate these observables with confidence, the direction of future theoretical efforts, and limitations to current (and future) approaches. This paper is an extension of a similar paper presented at the International Centre for Theoretical Physics in 1996

  14. Considerations in the design of an improved transportable neutron spectrometer

    CERN Document Server

    Williams, A M; Brushwood, J M; Beeley, P A

    2002-01-01

    The Transportable Neutron Spectrometer (TNS) has been used by the Ministry of Defence for over 15 years to characterise neutron fields in workplace environments and provide local correction factors for both area and personal dosimeters. In light of advances in neutron spectrometry, a programme to evaluate and improve TNS has been initiated. This paper describes TNS, presents its operation in known radioisotope fields and in a reactor environment. Deficiencies in the operation of the instrument are highlighted, together with proposals for updating the response functions and spectrum unfolding methodologies.

  15. Decay studies of the highly neutron-deficient indium isotopes

    International Nuclear Information System (INIS)

    Wouters, J.M.

    1982-02-01

    An extension of the experimentally known nuclidic mass surface to nuclei far from the region of beta-stability is of fundamental interest in providing a better determination of the input parameters for the various nuclear mass formulae, allowing a more accurate prediction of the ultimate limits of nuclear stability. In addition, a study of the shape of the mass surface in the vicinity of the doubly-closed nuclide 100 Sn provides initial information on the behavior of the shell closure to be expected when Z = N = 50. Experiments measuring the decay energies of 103 105 In by β-endpoint measurements are described with special attention focused on the development of a plastic scintillator β-telescope coupled to the on-line mass separator RAMA (Recoil Atom Mass Analyzer). An attempt to measure the β-endpoint energy of 102 In is also briefly described. The experimentally determined decay energies and derived masses for 103 105 In are compared with the predictions of different mass models to identify which models are more successful in this region. Furthermore, the inclusion in these comparisons of the available data on the neutron-rich indium nuclei permits a systematic study of their ground state mass behavior as a function of the neutron number between the shell closures at N = 50 and N = 82. These analyses indicate that the binding energy of 103 In is 1 MeV larger than predicted by the majority of the mass models. An examination of the Q/sub EC/ surface and the single- and two-neutron separation energies in the vicinity of 103 105 In is also performed to investigate further the deviation and other possible systematic variations in the mass surface in a model-independent way

  16. Structure of liquid Te-based alloys used in rewritable DVDs

    Energy Technology Data Exchange (ETDEWEB)

    Delheusy, M.; Raty, J.Y.; Detemple, R.; Welnic, W.; Wuttig, M.; Gaspard, J.-P

    2004-07-15

    We analyze the structure of Te-based chalcogenide compounds that are used as materials for rewritable DVDs by using a combination of neutron diffraction and ab initio computer simulation. We show that in the liquid, the atoms have a low average coordination number, as the result of a Peierls distortion. The partial pair correlation functions are obtained from the computer simulation data.

  17. Neutron dosimeters and survey meters in accelerators, reactors and other neutron environments

    International Nuclear Information System (INIS)

    1989-03-01

    Neutron fields in occupationally accessible areas around nuclear reactors, radioisotope sources and medical and high energy accelerators have been characterized using currently available information. Neutron, rem meters, such as the Leake detector, are the most suitable instruments available for conducting neutron dose rate surveys in the vicinity of radioisotope neutron sources, nuclear reactors and medical accelerators. However, these instruments have been shown to be deficient in that they overrespond by a factor of four to neutrons in the 0.1 to 1 MeV range and are insensitive to neutrons from about 1 eV up to about 10 keV. Also, they are insensitive to neutrons above 20 MeV and their use must be restricted near high energy accelerators where significant numbers of neutrons above 20 MeV are known to be present. The most suitable instrument of measure dose from neutrons above 20 MeV is the 12 C(n,2n) 11 C scintillation chamber. Commercially available rem meters frequently use BF 3 counters in the pulse mode to detect thermal neutrons. Therefore, measurements around pulsed accelerators must be made with caution to ensure that the detector is not saturated during each pulse and that the accelerator pulse period is greater than the response time of the detector. The personal neutron dosimeters currently available either are known to be insensitive to neutrons above 20 MeV or have not been tested. Also, all except the albedo dosimeter are insensitive to or have not been tested for neutron energies in the range 1 eV to 10 keV. Several dosimeter types respond reasonably well to neutrons in the energy range 0.1 to 15 MeV, for example, CR-39, bubble and superheated drop detectors. However, the first gas a lower limit of sensitivity of about 0.3 mSv. The bubble detector can be designed to measure doses as small as 1μSv and offers the additional benefit of direct-reading capability. The superheated drop detector is not suitable for use around pulsed accelerators because

  18. Neutron activation analysis of high purity tellurium

    International Nuclear Information System (INIS)

    Gil'bert, Eh.N.; Verevkin, G.V.; Obrazovskij, E.G.; Shatskaya, S.S.

    1980-01-01

    A scheme of neutron activation analysis of high purity tellurium is developed. Weighed amount of Te (0.5 g) is irradiated for 20-40 hr in the flux of 2x10 13 neutron/(cm 2 xs). After decomposition of the sample impurities of gold and palladium are determined by the extraction with organic sulphides. Tellurium separation from the remaining impurities is carried out by the extraction with monothiobenzoic acid from weakly acidic HCl solutions in the presence of iodide-ions, suppressing silver extraction. Remaining impurity elements in the refined product are determined γ-spectrometrically. The method allows to determine 34 impurities with determination limits 10 -6 -10 -11 g

  19. Neutron activation analysis of manganese-mercury telluride

    International Nuclear Information System (INIS)

    Sadykov, I. I.

    2003-01-01

    The triple semiconductor compound Mn x Hg 1-x Te is a worthwhile material for the development of infra-red detectors. It's properties, as well as other semiconductors ones depend on impurity elements content. So, analytical Purity control of Mn x Hg 1-x Te is required. Some procedures of the neutron activation analysis of Te[1], Hg [2] and that of their compounds (Cd x Hg 1-x Te [3], for instance) have been developed recently. However, no papers on the NAA of Mn x Hg 1-x Te have been found. This paper describes the procedure of the NAA of Mn x Hg 1-x Te based on anion-exchange chromatographic separation of impurity and matrix elements. Experimental The following reagents were used: commerciality available strongly based anion-exchange resin AW-17 (50-100 meash), hydrochloride hydrasine of analytical grade, solutions of HCl and HNO 3 prepared from concentrated acids of reagent grade. Separation processes were studied by radioactive tracers. The gamma-activity was measured on a HPGe detector GC1518 (efficiency 15 %, resolution 1,7 keV at 1332,5 keV line of 6 0C o) using DSA-1000 digital multichannel analyzer (Canberra, USA). Radioactive tracers were produced by irradiation of metals, salts or oxides of corresponding elements in WWR-SM water-water nuclear reactor. Irradiation of Mn x Hg 1-x Te samples and standards was carried out in a channel of WWR-SM reactor with a neutron flux density of 1.10 14 cm 2 .s -1 for 10 h. Solutions of manganese and mercury were prepared by dissolving their oxides in concentric hydrochloric acid. Solutions of tellurium were prepared by dissolving metallic tellurium in HCl:HNO 3 (3:1) mixture. Solution obtained was evaporated to dryness, the reside was dissolved in conc. HCl. To reduce tellurium to Te(IV) 1-2 mg of hydrazine were dissolved in solution at slight heating. Then, distilled water was added in a required quantities to get a desired concentration of HCl. The chromatographic behaviour of matrix and impurity elements was studied

  20. Strong anharmonicity in the phonon spectra of PbTe and SnTe from first principles

    Science.gov (United States)

    Ribeiro, Guilherme A. S.; Paulatto, Lorenzo; Bianco, Raffaello; Errea, Ion; Mauri, Francesco; Calandra, Matteo

    2018-01-01

    At room temperature, PbTe and SnTe are efficient thermoelectrics with a cubic structure. At low temperature, SnTe undergoes a ferroelectric transition with a critical temperature strongly dependent on the hole concentration, while PbTe is an incipient ferroelectric. By using the stochastic self-consistent harmonic approximation, we investigate the anharmonic phonon spectra and the occurrence of a ferroelectric transition in both systems. We find that vibrational spectra strongly depend on the approximation used for the exchange-correlation kernel in density-functional theory. If gradient corrections and the theoretical volume are employed, then the calculation of the phonon frequencies as obtained from the diagonalization of the free-energy Hessian leads to phonon spectra in good agreement with experimental data for both systems. In PbTe we evaluate the linear thermal expansion coefficient γ =2.3 ×10-5K-1 , finding it to be in good agreement with experimental value of γ =2.04 ×10-5K-1 . Furthermore, we study the phonon spectrum and we do reproduce the transverse optical mode phonon satellite detected in inelastic neutron scattering and the crossing between the transverse optical and the longitudinal acoustic modes along the Γ X direction. The phonon satellite becomes broader at high temperatures but its energy is essentially temperature independent, in agreement with experiments. We decompose the self-consistent harmonic free energy in second-, third-, and fourth-order anharmonic terms. We find that the third- and fourth-order terms are small. However, treating the third-order term perturbatively on top of the second-order self-consistent harmonic free energy overestimates the energy of the satellite associated with the transverse optical mode. On the contrary, a perturbative treatment on top of the harmonic Hamiltonian breaks down and leads to imaginary phonon frequencies already at 300 K. In the case of SnTe, we describe the occurrence of a ferroelectric

  1. Neutronic density perturbation by probes; Pertubacion de densidades neutronicas por sondas

    Energy Technology Data Exchange (ETDEWEB)

    Vigon, M A; Diez, L

    1956-07-01

    The introduction of absorbent materials of neutrons in diffuser media, produces local disturbances of neutronic density. The disturbance depends especially on the nature and size of the absorbent. Approximated equations which relates te disturbance and the distance to the absorbent in the case of thin disks have been drawn. The experimental comprobation has been carried out in two especial cases. In both cases the experimental results are in agreement with the calculated values from these equations. (Author)

  2. Study of proton and 2 protons emission from light neutron deficient nuclei around A=20

    International Nuclear Information System (INIS)

    Zerguerras, T.

    2001-09-01

    Proton and two proton emission from light neutron deficient nuclei around A=20 have been studied. A radioactive beam of 18 Ne, 17 F and 20 Mg, produced at the Grand Accelerateur National d'Ions Lourds by fragmentation of a 24 Mg primary beam at 95 MeV/A, bombarded a 9 Be target to form unbound states. Proton(s) and nuclei from the decay were detected respectively in the MUST array and the SPEG spectrometer. From energy and angle measurements, the invariant mass of the decaying nucleus could be reconstructed. Double coincidence events between a proton and 17 F, 16 O, 15 O, 14 O and 18 Ne were registered to obtain excitation energy spectra of 18 Ne, 17 F, 16 F, 15 F et 19 Na. Generally, the masses measures are in agreement with previous experiments. In the case of 18 Ne, excitation energy and angular distributions agree well with the predictions of a break up model calculation. From 17 Ne proton coincidences, a first experimental measurement of the ground state mass excess of 18 Na has been obtained and yields 24,19(0,15)MeV. Two proton emission from 17 Ne and 18 Ne excited states and the 19 Mg ground state was studied through triple coincidences between two proton and 15 O, 16 O and 17 Ne respectively. In the first case, the proton-proton relative angle distribution in the center of mass has been compared with model calculation. Sequential emission from excited states of 17 Ne, above the proton emission threshold, through 16 F is dominant but a 2 He decay channel could not be excluded. No 2 He emission from the 1.288 MeV 17 Ne state, or from the 6.15 MeV 18 Ne state has been observed. Only one coincidence event between 17 Ne and two proton was registered, the value of the one neutron stripping reaction cross section of 20 Mg being much lower than predicted. (author)

  3. Whole-Body Vibration Mimics the Metabolic Effects of Exercise in Male Leptin Receptor-Deficient Mice.

    Science.gov (United States)

    McGee-Lawrence, Meghan E; Wenger, Karl H; Misra, Sudipta; Davis, Catherine L; Pollock, Norman K; Elsalanty, Mohammed; Ding, Kehong; Isales, Carlos M; Hamrick, Mark W; Wosiski-Kuhn, Marlena; Arounleut, Phonepasong; Mattson, Mark P; Cutler, Roy G; Yu, Jack C; Stranahan, Alexis M

    2017-05-01

    Whole-body vibration (WBV) has gained attention as a potential exercise mimetic, but direct comparisons with the metabolic effects of exercise are scarce. To determine whether WBV recapitulates the metabolic and osteogenic effects of physical activity, we exposed male wild-type (WT) and leptin receptor-deficient (db/db) mice to daily treadmill exercise (TE) or WBV for 3 months. Body weights were analyzed and compared with WT and db/db mice that remained sedentary. Glucose and insulin tolerance testing revealed comparable attenuation of hyperglycemia and insulin resistance in db/db mice following TE or WBV. Both interventions reduced body weight in db/db mice and normalized muscle fiber diameter. TE or WBV also attenuated adipocyte hypertrophy in visceral adipose tissue and reduced hepatic lipid content in db/db mice. Although the effects of leptin receptor deficiency on cortical bone structure were not eliminated by either intervention, exercise and WBV increased circulating levels of osteocalcin in db/db mice. In the context of increased serum osteocalcin, the modest effects of TE and WBV on bone geometry, mineralization, and biomechanics may reflect subtle increases in osteoblast activity in multiple areas of the skeleton. Taken together, these observations indicate that WBV recapitulates the effects of exercise on metabolism in type 2 diabetes.

  4. Evolution of quadrupole and octupole collectivity north-east of $^{132}$ Sn: the even Te and Xe isotopes

    CERN Multimedia

    We propose to study excited states in isotopes north-east of the doubly-magic $^{132}$Sn by $\\gamma$-ray spectroscopy following "safe" Coulomb excitation. The experiment aims to the determine B(E2) and B(E3) values to follow the evolution of quadrupole and octupole collectivity when going away from the shell closures at Z = 50 and N = 82. The B(E2; 0$^+_{gs}$ $\\rightarrow$ 2$^+_{1}$) values in the even isotopes $^{138-144}$Xe have been measured at REX-ISOLDE and the systematic trend towards neutron-rich nuclei is well described even by an empirical Grodzins-type formula. An increasing dipole moment observed for $^{140,142}$Xe is interpreted as indirect signature of increasing octupole correlations peaking at N = 88. So far, no B(E3) values are known. In contrast to the Xe isotopes, the Te ones, in particular $^{136}$Te, are known for their notoriously irregular behaviour. In order to understand the nuclear structure also on a microscopic basis, the isotope $^{136}$Te with just one pair of protons and neutrons...

  5. Emergent nanoscale fluctuations in high rock-salt PbTe

    Science.gov (United States)

    Billinge, Simon

    2013-03-01

    Lead Telluride is one of the most promising thermoelectric materials in the temperature range just above room temperature. It is a narrow band gap semiconductor with a high Seebeck coefficient and a low thermal conductivity. It is structurally much simpler than many other leading candidates for high performance thermoelectrics being a binary rock-salt, isostructural to NaCl. The thermoelectric figure of merit, ZT, can be markedly improved by alloying with various other elements by forming quenched nanostructures. The undoped endmember, PbTe, does not have any such quenched nanostructure, yet has a rather low intrinsic thermal conductivity. There are also a number of interesting and non-canonical behaviors that it exhibits, such as an increasing measured band-gap with increasing temperature, exactly opposite to what is normally seen due to Fermi smearing of the band edge, and an unexpected non-monotonicity of the band gap in the series PbTe - PbSe - PbS. The material is on the surface simple, but hides some interesting complexity. We have investigated in detail the PbTe endmember using x-ray and neutron diffraction and neutron inelastic scattering. To our surprise, using the atomic pair distribution function (PDF) analysis of neutron powder diffraction data we found that an interesting and non-trivial local structure that appears on warming. with the Pb atoms moving off the high-symmetry rock-salt positions towards neighboring Te ions. No evidence for the off-centering of the Pb atoms is seen at low temperature. The crossover from the locally undistorted to the locally distorted state occurs on warming between 100 K and 250 K. This unexpected emergence of local symmetry broken distortions from an undistorted ground-state we have called emphanisis, from the Greek for appearing from nothing. We have also investigated the lattice dynamics of the system to search for a dynamical signature of this behavior and extended the studies to doped systems and I will also

  6. A coaxial double cylindrical TEPC for the microdosimetry of selected neutron energy bands in mixed fields of fast neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Saion, E.B.; Watt, D.E. (Saint Andrews Univ. (UK). Dept. of Physics); East, B.W. (Scottish Universities Research and Reactor Centre, Glasgow (UK)); Colautti, P. (Istituto Nazionale di Fisica Nucleare, Padua (Italy))

    1990-01-01

    A new low pressure tissue-equivalent proportional counter (TEPC) in a coaxial double cylindrical form has been developed to measure separately the microdose spectrum from any desired energy band of neutrons in the presence of mixed fields of faster neutrons, by selecting the thickness of the common TE dividing wall to be equivalent to the corresponding maximum proton ranges and by appropriate use of coincidence/anti-coincidence pulse arrangements. This thickness ensures charged particle equilibrium for the relevant neutron energy. Event spectra due to recoils generated by faster neutrons which interact with both the counters are removed completely by anti-coincidence techniques, thereby optimising the sensitivity of the inner microdosemeter to the event spectra of interest. The ability of this counter to discriminate in favour of events due to neutrons of energy <850 keV was achieved in microdosimetric measurements from mixed fields of a nuclear reactor. Mean values of lineal energy and quality factor for neutrons of energy <850 keV from a nuclear reactor were determined from the anti-coincidence spectrum. Good discrimination against {gamma} ray induced events is also achieved for the spectrum recorded in the anti-coincidence mode. This is an advantageous feature for other applications and requires further investigation. (author).

  7. A coaxial double cylindrical TEPC for the microdosimetry of selected neutron energy bands in mixed fields of fast neutrons

    International Nuclear Information System (INIS)

    Saion, E.B.; Watt, D.E.; Colautti, P.

    1990-01-01

    A new low pressure tissue-equivalent proportional counter (TEPC) in a coaxial double cylindrical form has been developed to measure separately the microdose spectrum from any desired energy band of neutrons in the presence of mixed fields of faster neutrons, by selecting the thickness of the common TE dividing wall to be equivalent to the corresponding maximum proton ranges and by appropriate use of coincidence/anti-coincidence pulse arrangements. This thickness ensures charged particle equilibrium for the relevant neutron energy. Event spectra due to recoils generated by faster neutrons which interact with both the counters are removed completely by anti-coincidence techniques, thereby optimising the sensitivity of the inner microdosemeter to the event spectra of interest. The ability of this counter to discriminate in favour of events due to neutrons of energy <850 keV was achieved in microdosimetric measurements from mixed fields of a nuclear reactor. Mean values of lineal energy and quality factor for neutrons of energy <850 keV from a nuclear reactor were determined from the anti-coincidence spectrum. Good discrimination against γ ray induced events is also achieved for the spectrum recorded in the anti-coincidence mode. This is an advantageous feature for other applications and requires further investigation. (author)

  8. Study on the dynamics of halogen elements in the agro-environment and these element`s deficiency, toxicity and environmental hazards by the application of the neutron activation analysis method

    Energy Technology Data Exchange (ETDEWEB)

    Yuita, Kouichi [National Inst. of Agro-Environmental Sciences, Tsukuba, Ibaraki (Japan)

    1998-03-01

    A neutron activation analysis method is an accurate and highly sensitive method for analyzing halogen elements (iodine, bromine and chlorine) except fluorine. It is unsubstitutable and valuable method especially for iodine (including radioactive {sup 129}I) and bromine which are present at lower levels. Halogen elements have high chemical and physiological activities and move widely in the environment. As a result, deficiency and an excess of halogen elements in plants and animals have occurred and artificial halogen compounds have caused environmental pollution in wide areas. We efficiently utilized the neutron activation analysis method and an activable tracer method to obtain valuable findings which contribute to the clarification of and measures against these actual problems and which are also concerned with the occurrence, distribution and migration of halogen elements in the environment, especially agricultural and forestry ecosystems in space and in time. (author)

  9. Post-scission fission theory: Neutron emission in fission

    International Nuclear Information System (INIS)

    Madland, D.G.

    1997-01-01

    A survey of theoretical representations of two of the observables in neutron emission in fission is given, namely, the prompt fission neutron spectrum N (E) and the average prompt neutron multiplicity bar ν p . Early representations of the two observables are presented and their deficiencies are discussed. This is followed by summaries and examples of recent theoretical models for the calculation of these quantities. Emphasis is placed upon the predictability and accuracy of the recent models. In particular, the dependencies of N (E) and bar ν p upon the fissioning nucleus and its excitation energy are treated. Recent work in the calculation of the prompt fission neutron spectrum matrix N (E, E n ), where E n is the energy of the neutron inducing fission, is then discussed. Concluding remarks address the current status of our ability to calculate these observables with confidence, the direction of future theoretical efforts, and limitations to current (and future) approaches

  10. Status of neutron dosimetry and damage analysis for the fusion materials program

    International Nuclear Information System (INIS)

    Greenwood, L.R.

    1979-01-01

    The status of neutron flux and spectral measurements is described for fusion material irradiations at reactor, T(d,n), Be(d,n), and spallation neutron sources. Such measurements are required for the characterization of an irradiation in terms of displacement damage, gas and transmutant production. Emphasis is placed on nuclear data deficiencies with specific recommendations for cross section measurements and calculations

  11. Neutron beams. Understanding and characterizing matter

    International Nuclear Information System (INIS)

    Pepy, G.

    2007-01-01

    This article treats of the numerous methods that use the undulatory properties of neutrons (their scattering in matter). Content: 1 - structure of crystallized matter: determination of a magnetic structure, hydrogen localization inside an alloy, 3D mapping of internal stresses inside materials, determination of the crystallographic structure, structure of a monocrystal by 4 circles diffraction; 2 - reflectometry, surface profiles: super-mirrors for neutron guides, giant magnetoresistance thin film devices; 3 - small angle scattering: protein and polyelectrolyte complexes, ropes integrity and microstructure, aggregates growth inside irradiated steels, microstructural evolution of defects inside race car engine pistons; 4 - dynamics: collective mode dynamics - three axis spectrometer, Mn Te magnons in thin film, scattering dynamics - quasi-elastic time-of-flight spectrometer, water diffusion inside cement. (J.S.)

  12. DOSIMETRIC response of a REM-500 in low energy neutron fields typical of nuclear power plants.

    Science.gov (United States)

    Aslam; Matysiak, W; Atanackovic, J; Waker, A J

    2012-06-01

    This study investigates the response of a REM-500 to assess neutron quality factor and dose equivalent in low energy neutron fields, which are commonly encountered in the workplace environment of nuclear power stations. The McMaster University 3 MV Van de Graaff accelerator facility was used to measure the response of the instrument in monoenergetic neutron fields in the energy range 51 to 727 keV by bombarding a thin LiF target with 1.93-2.50 MeV protons. The energy distribution of the neutron fields produced in the facility was measured by a (3)He filled gas ionization chamber. The MCA mode of the REM-500 instrument was used to collect lineal energy distributions at varying neutron energies and to calculate the frequency and dose-mean lineal energies. The effective quality factor, Q-, was also calculated using the values of Q(y)listed in the REM-500 operation manual and compared with those of ICRP 60. The authors observed a continuously increasing trend in y - F, y-D, and Q-with an increase in neutron energy. It is interesting to note that standard tissue equivalent proportional counters (TEPCs) filled with tissue equivalent(TE) gas give rise to a similar trend for these microdosimetric quantities of interest in the same energy range; however, the averages calculated in this study are larger by about 15%compared to a TEPC filled with propane-based TE gas probably because of the larger stopping power of protons in propane compared to TE gas. These somewhat larger event sizes did not result in any significant increase in the Q-compared to those obtained from a TEPC filled with TE gas and were found to be in good agreement with other measurements reported earlier at corresponding neutron energies. The instrument quality factor response, R(Q), defined as the ratio of measured quality factor to the calculated quality factor in an ICRU tissue sphere,was found to vary with neutron energy. The instrument response,R(Q), was ~0.6 at 727 keV, which deteriorates further to

  13. Theoretical models of neutron emission in fission

    International Nuclear Information System (INIS)

    Madland, D.G.

    1992-01-01

    A brief survey of theoretical representations of two of the observables in neutron emission in fission is given, namely, the prompt fission neutron spectrum N(E) and the average prompt neutron multiplicity bar v p . Early representations of the two observables are presented and their deficiencies are discussed. This is followed by summaries and examples of recent theoretical models for the calculation of these quantities. Emphasis is placed upon the predictability and accuracy of the new models. In particular, the dependencies of N(E) and bar v p upon the fissioning nucleus and its excitation energy are treated. Recent work in the calculation of the prompt fission neutron spectrum matrix N(E,E n ), where E n is the energy of the neutron inducing fission, is then discussed. Concluding remarks address the current status of our ability to calculate these observables with confidence, the direction of future theoretical efforts, and limititations to current and future calculations. Finally, recommendations are presented as to which model should be used currently and which model should be pursued in future efforts

  14. High density of (pseudo) periodic twin-grain boundaries in molecular beam epitaxy-grown van der Waals heterostructure: MoTe{sub 2}/MoS{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, Horacio Coy; Ma, Yujing; Chaghi, Redhouane; Batzill, Matthias [Department of Physics, University of South Florida, Tampa, Florida 33620 (United States)

    2016-05-09

    Growth of transition metal dichalcogenide heterostructures by molecular beam epitaxy (MBE) promises synthesis of artificial van der Waals materials with controllable layer compositions and separations. Here, we show that MBE growth of 2H-MoTe{sub 2} monolayers on MoS{sub 2} substrates results in a high density of mirror-twins within the films. The grain boundaries are tellurium deficient, suggesting that Te-deficiency during growth causes their formation. Scanning tunneling microscopy and spectroscopy reveal that the grain boundaries arrange in a pseudo periodic “wagon wheel” pattern with only ∼2.6 nm repetition length. Defect states from these domain boundaries fill the band gap and thus give the monolayer an almost metallic property. The band gap states pin the Fermi-level in MoTe{sub 2} and thus determine the band-alignment in the MoTe{sub 2}/MoS{sub 2} interface.

  15. Studies of Nuclei Close to 132Sn Using Single-Neutron Transfer Reactions

    International Nuclear Information System (INIS)

    Jones, K.L.; Pain, S.D.; Kozub, R.L.; Adekola, Aderemi S.; Bardayan, Daniel W.; Blackmon, Jeff C.; Catford, Wilton N.; Chae, K.Y.; Chipps, K.; Cizewski, J.A.; Erikson, Luke; Gaddis, A.L.; Greife, U.; Grzywacz, R.K.; Harlin, Christopher W.; Hatarik, Robert; Howard, Joshua A.; James, J.; Kapler, R.; Krolas, W.; Liang, J. Felix; Ma, Zhanwen; Matei, Catalin; Moazen, Brian; Nesaraja, Caroline D.; O'Malley, Patrick; Patterson, N.P.; Paulauskas, Stanley; Shapira, Dan; Shriner, J.F. Jr.; Sikora, M.; Sissom, D.J.; Smith, Michael Scott; Swan, T.P.; Thomas, J.S.; Wilson, Gemma L.

    2009-01-01

    Neutron transfer reactions were performed in inverse kinematics using radioactive ion beams of 132Sn, 130Sn, and 134Te and deuterated polyethylene targets. Preliminary results are presented. The Q-value spectra for 133Sn, 131Sn and 135Te reveal a number of previously unobserved peaks. The angular distributions are compatible with the expected lf7/2 nature of the ground state of 133Sn, and 2p3/2 for the 3.4 MeV state in 131Sn.

  16. Actinide neutron-induced fission up to 20 MeV

    International Nuclear Information System (INIS)

    Maslov, V.M.

    2001-01-01

    Fission and total level densities modelling along with double-humped fission barrier parameters allow to describe available actinide neutron-induced fission cross section data in the incident neutron energy range of ∼ 10 keV - 20 MeV. Saddle asymmetries relevant to shell correction model calculations influence fission barriers, extracted by cross section data analysis. The inner barrier was assumed axially symmetric in case of U, Np and Pu neutron-deficient nuclei. It is shown that observed irregularities in neutron-induced fission cross section data in the energy range of 0.5-3 MeV could be attributed to the interplay of few-quasiparticle excitations in the level density of fissioning and residual nuclei. Estimates of first-chance fission cross section and secondary neutron spectrum model were validated by 238 U fission, (n,2n) and (n,3n) data description up to 20 MeV. (author)

  17. Actinide neutron-induced fission up to 20 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Maslov, V M [Radiation Physics and Chemistry Problems Institute, Minsk-Sosny (Belarus)

    2001-12-15

    Fission and total level densities modelling along with double-humped fission barrier parameters allow to describe available actinide neutron-induced fission cross section data in the incident neutron energy range of {approx} 10 keV - 20 MeV. Saddle asymmetries relevant to shell correction model calculations influence fission barriers, extracted by cross section data analysis. The inner barrier was assumed axially symmetric in case of U, Np and Pu neutron-deficient nuclei. It is shown that observed irregularities in neutron-induced fission cross section data in the energy range of 0.5-3 MeV could be attributed to the interplay of few-quasiparticle excitations in the level density of fissioning and residual nuclei. Estimates of first-chance fission cross section and secondary neutron spectrum model were validated by {sup 238}U fission, (n,2n) and (n,3n) data description up to 20 MeV. (author)

  18. Neutron beam applications - Development of single crystal structure analysis technique using the HANARO neutron four circle diffractometer

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Il Hwan; Kim, Moon Jib; Kim, Jin Gyu [Chungnam National University, Taejon (Korea)

    2000-04-01

    As the four circle diffractometer (FCD) has been set up in HANARO, it has become possible to study the single crystal structures by means of the neutron diffraction. Taking account of the geometry of the FCD, a program for the control of te FCD and neutron data acquisition operating under Windows' circumstance has been accomplished. Also, a computer program which can automatically measure the diffraction intensity data has been developed. All data obtained from the FCD are processed automatically for further work and a software for the single crystal structure analyses has been prepared. A KC1 single crystal was selected as first test sample for a structure analysis had been successfully performed on the FCD using in-house developed program and accordingly their functionings with precision were confirmed. For regular single crystal diffraction experiments, the structure analyses of chrysoberyl and Zr(Y)0{sub 1.87} single crystals were performed using both neutron and X-ray diffraction methods, and the result showed that the neutron diffraction work is superior to the X-ray one from the viewpoint of certain crystallographic information obtainable only from the former one. 24 refs., 15 figs., 15 tabs. (Author)

  19. Mild riboflavin deficiency is highly prevalent in school-age children but does not increase risk for anaemia in Cote d'Ivoire

    NARCIS (Netherlands)

    Rohner, F.; Zimmermann, M.B.; Wegmueller, R.; Tschannen, A.B.; Hurrell, R.F.

    2007-01-01

    There are few data on the prevalence of riboflavin deficiency in sub-Saharan Africa, and it remains unclear whether riboflavin status influences the risk for anaemia. The aims of this study were to: (1) measure the prevalence of riboflavin deficiency in children in south-central Côte d'Ivoire; (2)

  20. Detection of wood discoloration in a canker fungus-inoculated Japanese cedar by neutron radiography

    International Nuclear Information System (INIS)

    Yamada, T.; Aoki, Y.; Yamato, M.; Komatsu, M.; Kusumoto, D.; Suzuki, K.; Nakanishi, T.M.

    2005-01-01

    Neutron radiography (NRG) was applied to trace the development of discolored tissue in the wood of Japanese cedar (Cryptomeria japonica) after being infected with a canker fungus. Japanese cedar seedlings were wound inoculated with a virulent and avirulent isolate of a canker fungus, Guignardia cryptomeriae. Three, 7, 13 and 22 days after the inoculation, the seedlings were irradiated with thermal neutrons. The image on the X-ray film showed that the whiteness in the image corresponded to the water content in the sample. Discolored tissue and surrounding dry zones induced by the fungal inoculation were detected as dark areas, indicating water deficiency with a high resolution. Through image analysis, the dry zones were detected as early as 3 days after inoculation. Neutron images also showed the difference in the size of water deficient parts due to the tissue damage among the treatments. The neutron beam dose used in this experiment had no effect on the growth rate of the fungus on a medium, showing that NRG is an effective method for pathological research of trees. (author)

  1. Alpha decay of 114Ba

    International Nuclear Information System (INIS)

    Mazzocchi, C.; Janas, Z.; Batist, L.; Belleguic, V.; Doering, J.; Kapica, M.; Kirchner, R.; Roeckl, E.; Gierlik, M.; Zylicz, J.; Mahmud, H.; Schmidt, K.; Woods, P.J.

    2003-01-01

    The neutron-deficient isotope 114 Ba was produced in a fusion evaporation reaction at the GSI On-Line Mass Separator. We measured the α-particle energy of 114 Ba, the half-life of its daughter nucleus 110 Xe, and the α-decay branching ratios for 114 Ba, 110 Xe and 106 Te. (orig.)

  2. Post-Irradiation Behaviour of I{sup 131} in TeO{sub 2}; Comportement de {sup 131}I Dans TeO{sub 2} Apres Irradiation; 041f 041e 0412 0415 0414 0415 041d 0418 0415 0419 041e 0414 0410 -131 0412 TeO{sub 2} 0433 041f 041e 0421 041b 0415 041e 0411 041b 0423 0427 0415 041d 0418 042f ; Comportamiento del {sup 131}I en TeO{sub 2} Despues de su Irradiacion

    Energy Technology Data Exchange (ETDEWEB)

    Jacimovic, Lj.; Stevovic, J.; Veljkovic, S. R. [Boris Kidric Institute of Nuclear Sciences, Belgrade, Yugoslavia (Serbia)

    1965-04-15

    The system I{sup 131} in TeO{sub 2} is interesting because little is known about thermal chemical changes in this target. Radioiodine was produced by neutron irradiation of TeO{sub 2} in the reactor. Irradiated TeO{sub 2} was dissolved in diluted NaOH. The analysis of the iodine valency forms was made by ion exchange techniques. The thermal and radiation stability of TeO{sub 2} was studied by using the spectrophotometric method for the determination of tellurium. Post-irradiation annealing of I{sup 131} in TeO{sub 2} was studied in dependence on the time and temperature of the heating. The main tendency of annealing was the reduction of radioiodine. The time dependence of this process indicates a fast change at high temperatures. The curves are more complex at lower temperatures. The annealing may appear complex because of the variety of thermal reactions of iodine intermediary. It may react with products of the following processes: tellurium recoil and corresponding hot zone, beta transition of Te{sup 131} and TeO{sub 2} itself. The kinetics of these changes was considered and an estimation of the processes during annealing was made. The influence of the neutron flux on the kinetics of annealing was also studied. (author) [French] Le cas de 131I dans TeO{sub 2} presente un interet en raison du peu de connaissances dont on dispose sur les modifications chimico-thermiques dans cette cible. Les auteurs ont obtenu le radioiode par exposition de TeO{sub 2} aux neutrons en pile, puis dissous TeO{sub 2} irradie dans NaOH dilue. Ils ont fait l'analyse des divers etats de valence de l'iode par des procedes d'echange d'ions. Ils ont etudie la stabilite thermique et la radiostabilite de TeO{sub 2} en recourant a la methode spectrophotometrique pour la determination du tellure. Ils ont etudie le recuit de 131I dans TeO{sub 2} apres irradiation en fonction du temps et de la temperature de chauffage. La tendance du recuit a ete surtout une tendance a la reduction du radioiode

  3. Phonon Density of States and Heat Capacity of La3-xTe4

    International Nuclear Information System (INIS)

    Delaire, Olivier A.; May, Andrew F.; McGuire, Michael A.; Porter, Wallace D.; Lucas, Matthew S.; Stone, Matthew B.; Abernathy, Douglas L.; Snyder, G.J.

    2009-01-01

    The phonon density of states (DOS) of La 3-x Te 4 compounds (x=0.0, 0.18, 0.32) was measured at 300, 520, and 780 K, using inelastic neutron scattering. A significant stiffening of the phonon DOS, and a large broadening of features were observed upon introduction of vacancies on La sites (increasing x). Heat capacity measurements were performed at temperatures ∼1.85 ≤ T ≤ 1200 K and were analyzed to quantify the contributions of phonons and electrons. The Debye temperature and the electronic coefficient of heat capacity determined from these measurements are consistent with the neutron scattering results, and with previously reported first-principles calculations. Our results indicate that La vacancies in La 3-x Te 4 strongly scatter phonons, and this source of scattering appears to be independent of temperature. The stiffening of the phonon DOS induced by the introduction of vacancies is explained in terms of the electronic structure and the change in bonding. The temperature dependence of the phonon DOS is captured satisfactorily by the quasiharmonic approximation.

  4. Neutron scattering techniques for structural studies of amorphous solids

    International Nuclear Information System (INIS)

    Wright, A.C.; Yarker, C.A.; Johnson, P.A.V.; Wedgwood, F.A.

    1976-01-01

    Preliminary data are presented for a series of glasses using some of the special features of neutron diffraction. In vitreous K 2 O x TiO 2 x 2SiO 2 each Ti atom is on average surrounded by 5.2 oxygen atoms at a distance of 1.95 A, whereas the structure of V 2 O 5 x TeO 2 is dominated by distorted TeO 6 octahedra. Features in the magnetic correlation function for vitreous O x 79Fe 2 O 3 x P 2 O 5 occur at the Fe,Fe distance found in crystalline FePO 4 . (orig.) [de

  5. Recent cross-section measurements of neutron-induced reactions of importance for background estimates in 0νββ searches

    Science.gov (United States)

    Tornow, W.; Bhike, M.; Finch, S. W.; Krishichayan

    2017-09-01

    We report on cross-section measurements for the reactions 76Ge(n,2n)75Ge, 76Ge(n,n'γ)76Ge, 126,127,128Te(n,γ)127,129,131Te, and 136Xe(n,n'γ)136Xe in the neutron energy range between 0.5 MeV and 15 MeV.

  6. Neutron Activation Resonance Integrals of 74Se, 78Se, 80Se, 81Br, 127I, 130Te, 138Ba, 140Ce, and 142Ce

    International Nuclear Information System (INIS)

    Ricabarra, M. D.; Turjanskl, R.; Ricabarra, G. H.; Bigham, C.B.

    1968-01-01

    A lithium-drift germanium γ-ray spectrometer has been used to make accurate intercomparisons of the ratio of resonance-integral to thermal-activation cross section by measuring cadmium ratios or relative activation rates in two different neutron spectra. The standard, gold, or secondary standard, indium, was mixed uniformly in the samples and the activities resolved with the spectrometer. Expressed as Westcott S 0 values, the results relative to S 0 = 17.7 for gold were as follows: 74 Se = 10.3 +± 0.1, 78 Se = 12.3 ± 0.3, 80 Sc = 2.65 ± 0.02, 81 Br = 24.3 ± 0.5, 127 I = 27.8 ± 0.5, 130 Te = 2.10 ± 0.07, 138 Ba = 0.649 ± 0.004, 140 Ce = 0.476 ± 0.003, 142 Ce = 0.865 ± 0.005. (author)

  7. Laboratory tests on neutron shields for gamma-ray detectors in space

    CERN Document Server

    Hong, J; Hailey, C J

    2000-01-01

    Shields capable of suppressing neutron-induced background in new classes of gamma-ray detectors such as CdZnTe are becoming important for a variety of reasons. These include a high cross section for neutron interactions in new classes of detector materials as well as the inefficient vetoing of neutron-induced background in conventional active shields. We have previously demonstrated through Monte-Carlo simulations how our new approach, supershields, is superior to the monolithic, bi-atomic neutron shields which have been developed in the past. We report here on the first prototype models for supershields based on boron and hydrogen. We verify the performance of these supershields through laboratory experiments. These experimental results, as well as measurements of conventional monolithic neutron shields, are shown to be consistent with Monte-Carlo simulations. We discuss the implications of this experiment for designs of supershields in general and their application to future hard X-ray/gamma-ray experiments...

  8. First direct constraints on Fierz interference in free-neutron β decay

    Science.gov (United States)

    Hickerson, K. P.; Sun, X.; Bagdasarova, Y.; Bravo-Berguño, D.; Broussard, L. J.; Brown, M. A.-P.; Carr, R.; Currie, S.; Ding, X.; Filippone, B. W.; García, A.; Geltenbort, P.; Hoagland, J.; Holley, A. T.; Hong, R.; Ito, T. M.; Knecht, A.; Liu, C.-Y.; Liu, J. L.; Makela, M.; Mammei, R. R.; Martin, J. W.; Melconian, D.; Mendenhall, M. P.; Moore, S. D.; Morris, C. L.; Pattie, R. W.; Pérez Galván, A.; Picker, R.; Pitt, M. L.; Plaster, B.; Ramsey, J. C.; Rios, R.; Saunders, A.; Seestrom, S. J.; Sharapov, E. I.; Sondheim, W. E.; Tatar, E.; Vogelaar, R. B.; VornDick, B.; Wrede, C.; Young, A. R.; Zeck, B. A.; UCNA Collaboration

    2017-10-01

    Precision measurements of free-neutron β decay have been used to precisely constrain our understanding of the weak interaction. However, the neutron Fierz interference term bn, which is particularly sensitive to beyond-standard-model tensor currents at the TeV scale, has thus far eluded measurement. Here we report the first direct constraints on this term, finding bn=0.067 ±0 .005stat-0.061+0.090sys , consistent with the standard model. The uncertainty is dominated by absolute energy reconstruction and the linearity of the β spectrometer energy response.

  9. Understanding arsenic incorporation in CdTe with atom probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Burton, G. L.; Diercks, D. R.; Ogedengbe, O. S.; Jayathilaka, P. A. R. D.; Edirisooriya, M.; Myers, T. H.; Zaunbrecher, K. N.; Moseley, J.; Barnes, T. M.; Gorman, B. P.

    2018-08-01

    Overcoming the open circuit voltage deficiency in Cadmium Telluride (CdTe) photovoltaics may be achieved by increasing p-type doping while maintaining or increasing minority carrier lifetimes. Here, routes to higher doping efficiency using arsenic are explored through an atomic scale understanding of dopant incorporation limits and activation in molecular beam epitaxy grown CdTe layers. Atom probe tomography reveals spatial segregation into nanometer scale clusters containing > 60 at% As for samples with arsenic incorporation levels greater than 7-8 x 10^17 cm-3. The presence of arsenic clusters was accompanied by crystal quality degradation, particularly the introduction of arsenic-enriched extended defects. Post-growth annealing treatments are shown to increase the size of the As precipitates and the amount of As within the precipitates.

  10. Neutron therapy in the 21. century

    International Nuclear Information System (INIS)

    Kroc, Thomas K.; Welsh, James S.

    2015-01-01

    The question of whether or not neutron therapy works has been answered. It is a qualified yes, as is the case with all of radiation therapy. But, neutron therapy has not kept pace with the rest of radiation therapy in terms of beam delivery techniques. Modern photon and proton based external beam radiotherapy routinely implements image-guidance, beam intensity-modulation and 3-dimensional treatment planning. The current iteration of fast neutron radiotherapy does not. Addressing these deficiencies, however, is not a matter of technology or understanding, but resources. The future of neutron therapy lies in better understanding the interaction processes of radiation with living tissue. A combination of radiobiology and computer simulations is required in order to optimise the use of neutron therapy. The questions that need to be answered are: Can we connect the macroscopic with the microscopic? What is the optimum energy? What is the optimum energy spectrum? Can we map the sensitivity of the various tissues of the human body and use that knowledge to our advantage? And once we gain a better understanding of the above radiobiological issues will we be able to capitalise on this understanding by precisely and accurately delivering fast neutrons in a manner comparable to what is now possible with photons and protons? This presentation will review the accomplishments to date. It will then lay out the questions that need to be answered for neutron therapy to truly be a 21. century therapy. (authors)

  11. Iodine as an oxidant in the topotactic deintercalation of interstitial iron in Fe(1+x)Te.

    Science.gov (United States)

    Rodriguez, Efrain E; Zavalij, Peter; Hsieh, Ping-Yen; Green, Mark A

    2010-07-28

    The layered telluride, Fe(1+x)Te, is a parent compound of the isostructural and superconducting phases, Fe(1+x)(Te, Se, S). Here we show that, through a simple reaction of I(2) vapor with both powder and single crystal samples, the interstitial iron can be removed from the FeTe framework topotactically. Neutron powder diffraction and X-ray single crystal diffraction confirm that the iron being extracted is the partially occupied site that lies between the 2-D blocks of edge-sharing FeTe(4) tetrahedra. The deintercalation process has consequences for both magnetic and crystallographic phase transitions in the compound at low temperatures. This technique could be of use for the tuning of stoichiometry of the superconducting phases and therefore enable more careful studies on how chemical composition affects magnetic and superconducting properties.

  12. Calibration of a spectrometry multisphere system for neutron fields

    International Nuclear Information System (INIS)

    Carelli, Jorge L.; Cruzate, Juan A.; Papadopulos, Susana B.; Gregori, Beatriz N.; Ciocci Brazzano, Ligia

    2005-01-01

    In this work it is presented the calibration of the neutrons spectrometric system of the Nuclear Regulatory Authority (ARN) in the Institut de Protection et Sure te Nucleaires (Ipn), Labourite dadaist et de Recherche s en Dosimetric Extern e, Cadarache, France. The multisphere system is composed of 9 polyethylene spheres of high density, with a gaseous detector of 3 He and associate electronics. The matrix of energy response to the system neutrons was obtained applying the MCNPX code for the range of energies between thermal and 100 MeV with cross sections taken from library ENDF/B-VI. The neutron spectra of the multisphere system were obtained applying the deconvolution code LOUHI82. The relationship between the theoretical responses and the experiences obtained with the AmBe and 252 Cf sources are also presented in this work [es

  13. Chemical transformations associated with neutronic irradiation of telluric acid

    International Nuclear Information System (INIS)

    Bertet, M.

    1963-01-01

    The chemical transformations which arise from irradiation of telluric acid with neutrons have been studied under several experimental conditions. The effects of the reaction (n, γ ) on Te VI and of the isomeric transitions 131m Te VI → 131 Te and 129m Te VI → 129 Te, and the oxidation states of 131 I formed by β decay of 131 Te have been investigated in detail. The Szilard-Chalmers effect has been put in evidence. Retention (R) depends on the isomeric state of Rd-Te and is higher for the metastable isotopes. R increases with the time of irradiation. R seems to be independent of the medium which is used for dissolving telluric acid irradiated in the solid state. Higher values of R are found if the acid is irradiated in neutral or alkaline solution; irradiation in acid solution leads to lower values for R. Retention for 131 Te VI and 129 Te VI formed by isomeric transition depends on the pH of the solution where this disintegration occurs. For instance, with 129 Te, R is greater in 6 M NaOH (80 per cent) than in 3 M HCI (40 per cent). The relative amounts of the oxidation states of 131 I (reduced fraction (I - , IO - , I 2 ), iodate and periodate) depend on the medium, both if the acid is irradiated in the solid state and it is irradiated in solution. In the first case, the reduced fraction increases from 12 to 89 per cent when the dissolving medium is changed from neutral to 0.8 M HNO 3 . In the second case, the reduced fraction is 90 per cent in neutral or acid solution and 64 per cent in 0.5 M KOH. It has been shown, furthermore, that microamounts of Te VI are formed in certain cases. (author) [fr

  14. Scaling neutron absorbed dose distributions from one medium to another

    International Nuclear Information System (INIS)

    Awschalom, M.; Rosenberg, I.; Ten Haken, R.K.

    1982-11-01

    Central axis depth dose (CADD) and off-axis absorbed dose ratio (OAR) measurements were made in water, muscle and whole skeletal bone TE-solutions, mineral oil and glycerin with a clinical neutron therapy beam. These measurements show that, for a given neutron beam quality and field size, there is a universal CADD distribution at infinity if the depth in the phantom is expressed in terms of appropriate scaling lengths. These are essentially the kerma-weighted neutron mean free paths in the media. The method used in ICRU No. 26 to scale the CADD by the ratio of the densities is shown to give incorrect results. the OAR's measured in different media at depths proportional to the respective mean free paths were also found to be independent of the media to a good approximation. It is recommended that relative CADD and OAR measurements be performed in water because of its universality and convenience. A table of calculated scaling lengths is given for various neutron energy spectra and for various tissues and materials of practical importance in neutron dosimetry

  15. Nucleosynthesis of neutron-rich heavy nuclei during explosive helium burning in massive stars

    International Nuclear Information System (INIS)

    Blake, J.B.; Woosley, S.E.; Weaver, T.A.; Schramm, D.N.

    1981-01-01

    The production of heavy nuclei during explosive helium burning has been calculated using a hydrodynamical model of a 15 M/sub sun/ (Type II) supernovae and a n-process nuclear reaction network. The resulting neutron-rich heavy nuclei are not produced in the relative abundances of solar-system r-process material, especially in the vicinity of Pt, nor are any actinides produced. These deficiencies reflect an inadequate supply of neutrons. However, some neutron-rich isotopes, normally associated with the r-process, are produced which may be significant for the production of isotopic anomalies in meteorites

  16. Astrophysical implications of hypothetical stable TeV-scale black holes

    CERN Document Server

    Giddings, Steven B

    2008-01-01

    We analyze macroscopic effects of TeV-scale black holes, such as could possibly be produced at the LHC, in what is regarded as an extremely hypothetical scenario in which they are stable and, if trapped inside Earth, begin to accrete matter. We examine a wide variety of TeV-scale gravity scenarios, basing the resulting accretion models on first-principles, basic, and well-tested physical laws. These scenarios fall into two classes, depending on whether accretion could have any macroscopic effect on the Earth at times shorter than the Sun's natural lifetime. We argue that cases with such effect at shorter times than the solar lifetime are ruled out, since in these scenarios black holes produced by cosmic rays impinging on much denser white dwarfs and neutron stars would then catalyze their decay on timescales incompatible with their known lifetimes. We also comment on relevant lifetimes for astronomical objects that capture primordial black holes. In short, this study finds no basis for concerns that TeV-scale...

  17. Feasibility study on BNCT-SPECT using a CdTe detector

    International Nuclear Information System (INIS)

    Murata, Isao; Mukai, Taiki; Ito, Masao; Miyamaru, Hiroyuki; Yoshida, Shigeo

    2011-01-01

    There is no doubt that boron neutron capture therapy (BNCT) is a promising cancer therapy in the near future. At present, one of the severest problems to solve is monitoring of the treatment effect during neutron irradiation. It is known to be difficult in real time. So far, activation foils, small detectors and so on were used to measure the thermal neutron fluence in a certain place of the tumor. The dose distribution is thus estimated from the measured result and prediction with a transport code. In the present study, 478 keV gamma-rays emitted from the excited state of 7 Li produced by 10 B(n,α) 7 Li reaction are directly measured to realize real time monitoring of the treatment effect of BNCT. In this paper, the result of the feasibility study carried out using a Monte Carlo transport code is summarized. We used CdTe detectors with a quite narrow collimator to obtain a BNCT image keeping good spatial resolution. The intensity of capture gamma-rays of 2223 keV produced by 1 H(n,γ) 2 H reaction is very much higher than that of 478 keV. We thus adjusted the detector efficiency by selecting an appropriate thickness so as to optimize the efficiency ratio between 478 and 2223 keV. From the result of the detector response calculation, in case of 20 mm thick CdTe detector with the collimator of 2 mm in diameter, sufficient net count of ∼1000 for 478 keV in 30 min. was realized. It means an efficient and high-resolution BNCT-SPECT image could be obtained. (author)

  18. Gamma decay of the compound state and change of structure of the 124Te excited levels

    International Nuclear Information System (INIS)

    Sukhovoj, A.M.; Khitrov, V.A.

    2008-01-01

    Independent analysis of a large amount of data on the spectrum of gamma rays of the radiative capture of thermal neutrons in 123 Te (Σ(i γ E γ )/B n = 0.49) obtained in Rez made it possible to obtain new and reliable information on the dependence of sums of radiative strength functions of dipole gamma transitions on the energy of levels excited by them. These data, as does the level density in 124 Te, demonstrate a strong change of structure of the nucleus practically for the whole region of the levels excited by a captured neutron. As in the earlier studied nuclei (using data on the intensities of two-step cascades), it is possible to reproduce the stated parameters of the gamma-decay process to the accuracy of experiment only by the models directly taking into account the coexistence and interaction of the usual and superfluid component of the nuclear matter

  19. Gamma-ray spectroscopy of 120-130Te nuclei

    International Nuclear Information System (INIS)

    Vanhoy, J.R.; Champine, B.R.; Coleman, R.T.; Crandell, K.A.; Tanyi, J.A.; Hicks, S.F.; Alexander, G.K.; Burkett, P.G.; Burns, M.C.; Collard, C.J.

    2000-01-01

    Complete text of publication follows. Structure of the even 120-130 Te nuclei have been investigated with prompt gamma-ray spectroscopy following the 122-126,nat Te(n,n'γ) reactions and the (α,2nγ) 120,124,126 Te reactions. Gamma-ray excitation functions, angular distributions, γγ-coincidences, and Doppler shifts have been measured. Level schemes have been constructed to approximately 3.3 MeV excitation energy, and spectroscopic information including level spins and parities, branching and multipole-mixing ratios, and lifetimes have been extracted. Three different types of structure are thought to play an important role in these low-lying excitations. These are: collective, two-particle, and 4p-2h intruder excitations. Because there are seven stable even-even Te nuclei, the evolution of these excitation modes over this wide range in neutron number is investigated. Level sequences and transition rates obtained from these measurements are compared to IBM-2 model calculations both with and without intruder-state mixing by Rikovska et al. (1), and to particle-vibrational coupling model calculations by Lopac (2). The IBM-2 model calculations with intruder mixing well reproduce the level energies in the low-mass Te; however, examination of the electromagnetic transition rates reveals that there is no clear improvement in the description of these nuclei by adding the intruder configurations. Additionally, no evidence of the 2 + mixed-symmetry strength is observed in the 2 3 + and 2 4 + levels in these nuclei. The particle-vibration model calculations appear to do a good job describing both the level scheme and the transition rates in the heavier nuclei investigated. (author)

  20. Partial enthalpies of Bi and Te in Bi-Te melts and of In and Te in In-Te melts

    International Nuclear Information System (INIS)

    Yassin, Abeer; Amzil, Abdelhamid; Castanet, Robert

    2000-01-01

    Full text.Calorimetric measurement are reported which allow the enthalpic behaviour of Bi-Te melts to be established. Further work is required, however, to supplement results obtained for In-Te melts. The partial enthalpies of bismuth and tellurium in the Bi-Te melts at 755K and those of indium and tellurium in the In-Te melts at 1010 and 987K were measured at high dilution by direct reaction calorimetry (drop method) with the help of a Tian-Calvet calorimeter. The limiting partial enthalpies of the components were deduced by extrapolation at infinite dilution: Δh f,∞ B i(755K)/KJ.mol -1 = -34.0 and Δh f,∞ Te(755K) /KJ·mol -1 = -24.1 in the Bi-Te melts Δh f,∞ In(1010K) /KJ·mol -1 = -75.9 and Δh f,∞ Te(1010K) /KJ·mol -1 = -47.8 in the In-Te melts Δh f,∞ In(987K) /KJ·mol -1 = -75.2 and Δh f,∞ Te(987K) /KJ·mol -1 = -48.0 in the In-Te melts

  1. Recent cross-section measurements of neutron-induced reactions of importance for background estimates in 0νββ searches

    Directory of Open Access Journals (Sweden)

    Tornow W.

    2017-01-01

    Full Text Available We report on cross-section measurements for the reactions 76Ge(n,2n75Ge, 76Ge(n,n′γ76Ge, 126,127,128Te(n,γ127,129,131Te, and 136Xe(n,n′γ136Xe in the neutron energy range between 0.5 MeV and 15 MeV.

  2. Radioactive ion beams produced by neutron-induced fission at ISOLDE

    CERN Document Server

    Catherall, R; Gilardoni, S S; Köster, U

    2003-01-01

    The production rates of neutron-rich fission products for the next-generation radioactive beam facility EURISOL are mainly limited by the maximum amount of power deposited by protons in the target. An alternative approach is to use neutron beams to induce fission in actinide targets. This has the advantage of reducing: the energy deposited by the proton beam in the target; contamination from neutron-deficient isobars that would be produced by spallation; and mechanical stress on the target. At ISOLDE CERN, tests have been made on standard ISOLDE actinide targets using fast neutron bunches produced by bombarding thick, high-Z metal converters with 1 and 1.4 GeV proton pulses. This paper reviews the first applications of converters used at ISOLDE. It highlights the different geometries and the techniques used to compare fission yields produced by the proton beam directly on the target with neutron-induced fission. Results from the six targets already tested, namely UC2/graphite and ThO2 targets with tungsten an...

  3. Study of proton and 2 protons emission from light neutron deficient nuclei around A=20; Etude de l'emission proton et de deux protons dans les noyaux legers deficients en neutrons de la region A=20

    Energy Technology Data Exchange (ETDEWEB)

    Zerguerras, T

    2001-09-01

    Proton and two proton emission from light neutron deficient nuclei around A=20 have been studied. A radioactive beam of {sup 18}Ne, {sup 17}F and {sup 20}Mg, produced at the Grand Accelerateur National d'Ions Lourds by fragmentation of a {sup 24}Mg primary beam at 95 MeV/A, bombarded a {sup 9}Be target to form unbound states. Proton(s) and nuclei from the decay were detected respectively in the MUST array and the SPEG spectrometer. From energy and angle measurements, the invariant mass of the decaying nucleus could be reconstructed. Double coincidence events between a proton and {sup 17}F, {sup 16}O, {sup 15}O, {sup 14}O and {sup 18}Ne were registered to obtain excitation energy spectra of {sup 18}Ne, {sup 17}F, {sup 16}F, {sup 15}F et {sup 19}Na. Generally, the masses measures are in agreement with previous experiments. In the case of {sup 18}Ne, excitation energy and angular distributions agree well with the predictions of a break up model calculation. From {sup 17}Ne proton coincidences, a first experimental measurement of the ground state mass excess of {sup 18}Na has been obtained and yields 24,19(0,15)MeV. Two proton emission from {sup 17}Ne and {sup 18}Ne excited states and the {sup 19}Mg ground state was studied through triple coincidences between two proton and {sup 15}O, {sup 16}O and {sup 17}Ne respectively. In the first case, the proton-proton relative angle distribution in the center of mass has been compared with model calculation. Sequential emission from excited states of {sup 17}Ne, above the proton emission threshold, through {sup 16}F is dominant but a {sup 2}He decay channel could not be excluded. No {sup 2}He emission from the 1.288 MeV {sup 17}Ne state, or from the 6.15 MeV {sup 18}Ne state has been observed. Only one coincidence event between {sup 17}Ne and two proton was registered, the value of the one neutron stripping reaction cross section of {sup 20}Mg being much lower than predicted. (author)

  4. Dependence of charge collection distributions and dose on the gas type filling the ionization chamber for a p(66)Be(49) clinical neutron beam

    International Nuclear Information System (INIS)

    Awschalom, M.; Haken, R.K.T.

    1985-01-01

    Measurements of central axis depth charge distributions (CADCD) in a p(66)Be(49) clinical neutron beam using A-150 TE plastic ionization chambers (IC) have shown that these distributions are dependent on the gas type filling the ICs. IC volumes from 0.1 to 8 cm 3 and nine different gases were investigated. Off axis ratios and build-up measurements do not seem to be as sensitive to gas type. The gas dosimetry constants given in the AAPM Protocol for Neutron Beam Dosimetry for air and methane based TE gases were tested for consistency in water and in TE solution filled phantoms at depths of 10 cm, when used in conjunction with an IC having 5 mm thick walls of A-150. 29 refs., 7 figs., 1 tab

  5. Cancer risks and neutron RBE's from Hiroshima and Nagasaki

    International Nuclear Information System (INIS)

    Dobson, R.L.; Straume, T.

    1982-01-01

    The new radiation dose estimates for Hiroshima and Nagasaki are radiobiologically examined for compatability with other human and experimental data. The new doses show certain improvements over the original T65 doses. However, they suggest for chronic granulocytic leukemia, total malignancies, and chromosome aberrations, at neutron doses of 1 rad, RBEs in excess of 100, higher than expected from other findings. This and other indications suggest that either there are unrecognized systematic problems with the various radiobiological data, or the new doses are deficient in neutrons for Hiroshima, by a factor of about five. If in fact there were actually some 5-fold more dose from neutrons at Hiroshima than estimated by the new calculations, the RBEs would agree well with laboratory results, and other inconsistencies would largely disappear. Cancer risks are estimated for neutrons from the new doses and are compared with those estimated from radiobiologically reconciled doses (the new doses adjusted by adding approximately 5-fold more neutrons). The latter appear more reasonable. For low-LET radiation, cancer risk estimates are changed very little by the new dose estimates for Nagasaki

  6. Structural chemistry and magnetic properties of the perovskite SrLa{sub 2}Ni{sub 2}TeO{sub 9}

    Energy Technology Data Exchange (ETDEWEB)

    Paria Sena, Robert; Hadermann, Joke [EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Chin, Chun-Mann; Hunter, Emily C. [Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR (United Kingdom); Battle, Peter D., E-mail: peter.battle@chem.ox.ac.uk [Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR (United Kingdom)

    2016-11-15

    A polycrystalline sample of SrLa{sub 2}Ni{sub 2}TeO{sub 9} has been synthesized using a standard ceramic method and characterized by neutron diffraction, magnetometry and electron microscopy. The compound adopts a monoclinic, perovskite-like structure with space group P2{sub 1}/n and unit cell parameters a=5.6008(1), b=5.5872(1), c=7.9018(2) Å, β=90.021(6)° at room temperature. The two crystallographically-distinct B sites are occupied by Ni{sup 2+} and Te{sup 6+} in ratios of 83:17 and 50:50. Both ac and dc magnetometry suggest that the compound is a spin glass below 35 K but the neutron diffraction data show that some regions of the sample are antiferromagnetic. Electron microscopy revealed twinning on a nanoscale and local variations in composition. These defects are thought to be responsible for the presence of two distinct types of antiferromagnetic ordering. - Highlights: • Coexistence of spin-glass and ordered phases. • Local inhomogeneity despite long-range inhomogeneity. • Contrasting magnetic properties of SrLa{sub 2}Ni{sub 2}TeO{sub 9} and La{sub 3}Ni{sub 2}SbO{sub 9}.

  7. Neutron diffraction studies of high-T/sub c/ superconductors

    International Nuclear Information System (INIS)

    Jorgensen, J.D.

    1988-03-01

    Neutron powder diffraction techniques have been used extensively for the study of high-T/sub c/ oxide superconductors because of the need to locate oxygen atoms and accurately determine the oxygen site occupancies, and the difficulty in obtaining single crystals. For example, in the case of YBa 2 Cu 3 O/sub 7-δ/, neutron powder diffraction and Rietveld structural refinement were used to obtain the first complete structural information. Subsequent experiments focussed on determining the relationship of superconducting properties to the number and distribution of oxygen vacancies on the Cu-O sublattice with measurements being done on samples in thermodynamic equilibrium, at high temperature in controlled oxygen atmospheres, and on metastable, oxygen-deficient samples produced by quenching. Neutron powder diffraction has also been used to determine the structures of compounds in which the properties have been modified by substitution on the Y, Ba, or Cu sites. This paper briefly reviews some of the neutron powder diffraction results in these areas. 17 refs

  8. Mutations for chlorophyll deficiency in barley: comparative effects of physical and chemical mutagens

    International Nuclear Information System (INIS)

    Constantin, M.J.

    1975-01-01

    The report concerns a comparison of effects from gamma rays, fission neutrons, and ethylmethane sulfonate based on chlorophyll-deficient mutant seedlings. Data from the literature and from the author's research are reviewed, and results are related to the practical application of mutation induction in barley breeding. (BSC) [de

  9. Study of proton and 2 protons emission from light neutron deficient nuclei around A=20; Etude de l'emission proton et de deux protons dans les noyaux legers deficients en neutrons de la region A=20

    Energy Technology Data Exchange (ETDEWEB)

    Zerguerras, T

    2001-09-01

    Proton and two proton emission from light neutron deficient nuclei around A=20 have been studied. A radioactive beam of {sup 18}Ne, {sup 17}F and {sup 20}Mg, produced at the Grand Accelerateur National d'Ions Lourds by fragmentation of a {sup 24}Mg primary beam at 95 MeV/A, bombarded a {sup 9}Be target to form unbound states. Proton(s) and nuclei from the decay were detected respectively in the MUST array and the SPEG spectrometer. From energy and angle measurements, the invariant mass of the decaying nucleus could be reconstructed. Double coincidence events between a proton and {sup 17}F, {sup 16}O, {sup 15}O, {sup 14}O and {sup 18}Ne were registered to obtain excitation energy spectra of {sup 18}Ne, {sup 17}F, {sup 16}F, {sup 15}F et {sup 19}Na. Generally, the masses measures are in agreement with previous experiments. In the case of {sup 18}Ne, excitation energy and angular distributions agree well with the predictions of a break up model calculation. From {sup 17}Ne proton coincidences, a first experimental measurement of the ground state mass excess of {sup 18}Na has been obtained and yields 24,19(0,15)MeV. Two proton emission from {sup 17}Ne and {sup 18}Ne excited states and the {sup 19}Mg ground state was studied through triple coincidences between two proton and {sup 15}O, {sup 16}O and {sup 17}Ne respectively. In the first case, the proton-proton relative angle distribution in the center of mass has been compared with model calculation. Sequential emission from excited states of {sup 17}Ne, above the proton emission threshold, through {sup 16}F is dominant but a {sup 2}He decay channel could not be excluded. No {sup 2}He emission from the 1.288 MeV {sup 17}Ne state, or from the 6.15 MeV {sup 18}Ne state has been observed. Only one coincidence event between {sup 17}Ne and two proton was registered, the value of the one neutron stripping reaction cross section of {sup 20}Mg being much lower than predicted. (author)

  10. Sociologia da deficiência: vozes por significados e práticas (mais inclusivas

    Directory of Open Access Journals (Sweden)

    Franco Ezequiel Harlos

    2015-05-01

    Full Text Available Na presente pesquisa objetiva-se sistematizar histórias e teorias associadas com a Sociologia da Deficiência, e identificar, nestes elementos sistematizados, vozes para repensar o significado da deficiência e práticas da Educação Especial. Para tanto, percorreu-se na pesquisa bibliográfica e documental 48 obras compiladas, primordialmente, da revista Disability and Society, da Asociación Española de Sociología de la Discapacidad e da base de dados do Centre of Disability Studies da Universidade de Leeds. As obras compiladas foram analisadas por meio de análise categorial. A primeira das categorias identificadas centra-se nas principais interpretações adotadas pelas Ciências da Saúde (paradigma médico para pensar a deficiência; a segunda, em histórias associadas com a constituição da Sociologia da Deficiência - nos movimentos sociais que, em resposta às interpretações da deficiência adotadas pelas Ciências da Saúde, (resignificaram a deficiência e fundaram os Estudos da Deficiência (Disability Studies; e, a terceira, nas múltiplas faces teóricas da Sociologia da Deficiência e nos novos modelos de compreensão da deficiência. A sistematização do conteúdo desvelou um paradigma sociológico de interpretação da deficiência: este paradigma apresenta vozes por significados e práticas mais inclusivas.

  11. /B(E2) values from low-energy Coulomb excitation at an ISOL facility: the /N=80,82 Te isotopes

    Science.gov (United States)

    Barton, C. J.; Caprio, M. A.; Shapira, D.; Zamfir, N. V.; Brenner, D. S.; Gill, R. L.; Lewis, T. A.; Cooper, J. R.; Casten, R. F.; Beausang, C. W.; Krücken, R.; Novak, J. R.

    2003-01-01

    B(E2;0+1→2+1) values for the unstable, neutron-rich nuclei 132,134Te were determined through Coulomb excitation, in inverse kinematics, of accelerated beams of these nuclei. The systematics of measured B(E2) values from the ground state to the first excited state have been extended to the N=82 shell closure in the Te nuclei and have been compared with the predictions of different theories. The measurements were performed at the Holifield Radioactive Ion Beam Facility (HRIBF) using the GRAFIK detector. The success of this approach, which couples a 5.7% efficient through-well NaI(Tl) γ-ray detector with thin foil microchannel plate beam detectors, also demonstrates the feasibility for Coulomb excitation studies of neutron-rich nuclei even further from the valley of beta stability, both at present-generation ISOL facilities and at the proposed Rare Isotope Accelerator.

  12. Ferromagnetism in Fe{sub 3-x-y}Ni{sub x}GeTe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Stahl, Juliane; Johrendt, Dirk [Muenchen Univ. (Germany). Dept. Chemie; Pomjakushin, Vladimir [Paul Scherrer Institute, Villigen (Switzerland). Lab. for Neutron Scattering

    2016-07-01

    Polycrystalline samples of Fe{sub 3-y}GeTe{sub 2} (0.08 ≤ y ≤ 0.29) and the solid solutions Fe{sub 3-x-y}Ni{sub x}GeTe{sub 2} (0.24 ≤ x ≤ 1.32; 0.14 ≤ y ≤ 0.41) were synthesized at 898-973 K in a resistance furnace and characterized by X-ray and neutron powder diffraction with Rietveld analysis (Fe{sub 3}GeTe{sub 2} type, P6{sub 3}/mmc, a = 402.665(3), c = 1632.820(14) pm for x = 0, y = 0.08). Fe{sub 3}Ge layers with planar FeGe hexagons and additional iron atoms above and below the rings are separated by double layers of tellurium atoms. Fe{sub 3}GeTe{sub 2} is ferromagnetic below T{sub C} = 230 K with magnetic moments aligned along the c axis. T{sub C} depends on the iron content and decreases with increasing iron vacancies continuously to 153 K in Fe{sub 2.71}GeTe{sub 2}. Further reduction of T{sub C} is possible by nickel substitution until magnetic ordering is nearly absent in Fe{sub 1.33}Ni{sub 1.32}GeTe{sub 2}. The suppression of the magnetic ordering is caused by random dilution of the magnetic iron atoms either by vacancies or by non-magnetic nickel atoms.

  13. Dosimetry with tissue-equivalent ionisation chambers in fast neutron fields for biomedical applications

    International Nuclear Information System (INIS)

    Zoetelief, J.; Broerse, J.J.

    1983-01-01

    The use of calibrated tissue-equivalent (TE) ionisation chambers is commonly considered to be the most practical method for total absorbed dose determinations in mixed neutron-photon fields for biomedical applications. The total absorbed dose can be derived from the charge produced within the cavity of an ionisation chamber employing a number of physical parameters. To arrive at the charge produced in the cavity several correction factors have to be introduced which are related to the operational characteristics of the chambers. Information on the operational characteristics of four TE ionisation chambers is presented in relation to ion collection, density and composition of gas in the cavity, wall thickness and effective point of measurement. In addition, some recent results from an ionisation chamber operated at high gas pressures are presented. The total absorbed doses derived from TE ionisation chambers show agreement within the uncertainty limits with results from other independent dosimetry methods, i.e., differential fluence measurements and a TE calorimeter. Conscientious experimentation and a common data base can provide dosimetry results with TE ionisation chambers with variations of less than +-2%. (author)

  14. Growth And Characterization Of LPE CdHgTe/CdZnTe/CdZnTe Structure

    Science.gov (United States)

    Pelliciari, B.; Chamonal, J. P.; Destefanis, G. L.; Dicioccio, L.

    1988-05-01

    The liquid phase epitaxial technique is used to grow Hgl_x Cdx Te (x = .23) from a Te - rich solution onto a Cdl_y ZnyTe (y = .04) buffer layer grown from a Te-rich solution onto a Cdi_yZnyTe bulk substrate in an open tube multibin horizontal slider apparatus.Growth conditions and physical characterizations of both the buffer layer and the CdHgTe layer are given ; electrical properties of the CdHgTe layer are also presen-ted. PV detectors were successfully obtained on such a structure using an ion-implanted technology and their characteristics at 77 K for a 10.1 ,um cut-off wavelength are given.

  15. Spin-isotropic continuum of spin excitations in antiferromagnetically ordered Fe1.07Te

    Science.gov (United States)

    Song, Yu; Lu, Xingye; Regnault, L.-P.; Su, Yixi; Lai, Hsin-Hua; Hu, Wen-Jun; Si, Qimiao; Dai, Pengcheng

    2018-02-01

    Unconventional superconductivity typically emerges in the presence of quasidegenerate ground states, and the associated intense fluctuations are likely responsible for generating the superconducting state. Here we use polarized neutron scattering to study the spin space anisotropy of spin excitations in Fe1.07Te exhibiting bicollinear antiferromagnetic (AF) order, the parent compound of FeTe1 -xSex superconductors. We confirm that the low-energy spin excitations are transverse spin waves, consistent with a local-moment origin of the bicollinear AF order. While the ordered moments lie in the a b plane in Fe1.07Te , it takes less energy for them to fluctuate out of plane, similar to BaFe2As2 and NaFeAs. At energies above E ≳20 meV, we find magnetic scattering to be dominated by an isotropic continuum that persists up to at least 50 meV. Although the isotropic spin excitations cannot be ascribed to spin waves from a long-range-ordered local-moment antiferromagnet, the continuum can result from the bicollinear magnetic order ground state of Fe1.07Te being quasidegenerate with plaquette magnetic order.

  16. Tunable (δπ, δπ)-Type Antiferromagnetic Order in α-Fe(Te,Se) Superconductors

    Science.gov (United States)

    Bao, Wei; Qiu, Y.; Huang, Q.; Green, M. A.; Zajdel, P.; Fitzsimmons, M. R.; Zhernenkov, M.; Chang, S.; Fang, Minghu; Qian, B.; Vehstedt, E. K.; Yang, Jinhu; Pham, H. M.; Spinu, L.; Mao, Z. Q.

    2009-06-01

    The new α-Fe(Te,Se) superconductors share the common iron building block and ferminology with the LaFeAsO and BaFe2As2 families of superconductors. In contrast with the predicted commensurate spin-density-wave order at the nesting wave vector (π, 0), a completely different magnetic order with a composition tunable propagation vector (δπ, δπ) was determined for the parent compound Fe1+yTe in this powder and single-crystal neutron diffraction study. The new antiferromagnetic order survives as a short-range one even in the highest TC sample. An alternative to the prevailing nesting Fermi surface mechanism is required to understand the latest family of ferrous superconductors.

  17. FLUKA Calculation of the Neutron Albedo Encountered at Low Earth Orbits

    CERN Document Server

    Claret, Arnaud; Combier, Natacha; Ferrari, Alfredo; Laurent, Philippe

    2014-01-01

    This paper presents Monte-Carlo simulations based on the Fluka code aiming to calculate the contribution of the neutron albedo at a given date and altitude above the Earth chosen by the user. The main input parameters of our model are the solar modulation affecting the spectra of cosmic rays, and the date of the Earth’s geomagnetic fi eld. The results consist in a two-parameter distribution, the neutron energy and the angle to the tangent plane of the sphere containing the orbi t of interest, and are provided by geographical position above the E arth at the chosen altitude. This model can be used to predict the te mporal variation of the neutron fl ux encountered along the orbit, and thus constrain the determination of the instrumental backg round noise of space experiments in low earth orbit.

  18. Total β-decay energies and atomic masses in regions far from β-stability

    International Nuclear Information System (INIS)

    Aleklett, K.

    1977-01-01

    This thesis is a summary of experimental investigations on total β-decay energies and deduced atomic masses of nuclei far from the region of β-stability. The Qsub(β) values are given for isotopes of Zn, Ga, Ge, As, Br, Rb, In, Sn, Sb, Te, Cs, Fr, Ra and Ac, with β-unstable nuclei. These unstable nuclei have very short half-lives, often below 10s, and the experimental techniques for the production, separation and collection of these short-lived nuclei are described. Neutron deficient nuclides were produced by spallation, in the ISOLDE facility, and neutron deficient nuclides were produced by thermal neutron induced fission of 235 U in the OSIRIS facility. β-spectra were recorded using an Si(Li)-detector and a coincidence system. Qsub(β) values obtained from mass formulae have been compared with experimental values obtained in different mass regions and a comparison made between results obtained from different droplet mass formulae. (B.D.)

  19. Thermochemical properties of silver tellurides including empressite (AgTe) and phase diagrams for Ag-Te and Ag-Te-O

    Science.gov (United States)

    Voronin, Mikhail V.; Osadchii, Evgeniy G.; Brichkina, Ekaterina A.

    2017-10-01

    This study compiles original experimental and literature data on the thermodynamic properties (ΔfG°, S°, ΔfH°) of silver tellurides (α-Ag2Te, β-Ag2Te, Ag1.9Te, Ag5Te3, AgTe) obtained by the method of solid-state galvanic cell with the RbAg4I5 and AgI solid electrolytes. The thermodynamic data for empressite (AgTe, pure fraction from Empress Josephine Mine, Colorado USA) have been obtained for the first time by the electrochemical experiment with the virtual reaction Ag + Te = AgTe. The Ag-Te phase diagrams in the T - x and log fTe2 (gas) - 1/ T coordinates have been refined, and the ternary Ag-Te-O diagrams with Ag-Te-TeO2 (paratellurite) composition range have been calculated.

  20. Cancer risks and neutron RBE's from Hiroshima and Nagasaki

    International Nuclear Information System (INIS)

    Dobson, R.L.; Straume, T.

    1982-01-01

    The new radiation dose estimates for Hiroshima and Nagasaki are here combined with epidemiologic data from the A-bomb survivors and examined radiobiologically for compatability with other human and experimental data. The new doses show certain improvements over the original T65 doses. However, they suggest for chronic granulocytic leukemia, total malignancies, and chromosome aberrations, at neutron doses of 1 rad, RBEs in excess of 100, higher than expected from other findings. This and other indications suggest that either there are unrecognized systematic problems with the various radiobiological data, or the new doses are deficient in neutrons for Hiroshima, by a factor of about five. If in fact there were actually some 5-fold more dose from neutrons at Hiroshima than estimated by the new calculations, the RBEs would agree well with laboratory results, and other inconsistencies would largely disappear. Cancer risks are estimated for neutrons from the new doses and are compared with those estimated from radiobiologically reconciled doses (the new doses adjusted by adding approximately 5-fold more neutrons). The latter estimates appear more reasonable. For low-LET radiation, cancer risk estimates are altered very little by the new dose estimates for Nagasaki

  1. CdTe as a passivating layer in CdTe/HgCdTe heterostructures

    International Nuclear Information System (INIS)

    Virt, I. S.; Kurilo, I. V.; Rudyi, I. A.; Sizov, F. F.; Mikhailov, N. N.; Smirnov, R. N.

    2008-01-01

    CdTe/Hg 1-x Cd x Te heterostructures are studied. In the structures, CdTe is used as a passivating layer deposited as a polycrystal or single crystal on a single-crystal Hg 1-x Cd x Te film. The film and a passivating layer were obtained in a single technological process of molecular beam epitaxy. The structure of passivating layers was studied by reflection high-energy electron diffraction, and the effect of the structure of the passivating layer on the properties of the active layer was studied by X-ray diffractometry. Mechanical properties of heterostructures were studied by the microhardness method. Electrical and photoelectrical parameters of the Hg 1-x Cd x Te films are reported.

  2. Conceptual design and neutronics analyses of a fusion reactor blanket simulation facility

    International Nuclear Information System (INIS)

    Beller, D.E.; Ott, K.O.; Terry, W.K.

    1987-01-01

    A new conceptual design of a fusion reactor blanket simulation facility has been developed. This design follows the principles that have been successfully employed in the Purdue Fast Breeder Blanket Facility (FBBF), where experiments have resulted in the discovery of substantial deficiencies in neutronics predictions. With this design, discrepancies between calculation and experimental data can be nearly fully attributed to calculation methods because design deficiencies that could affect results are insignificant. The conceptual design of this FBBF analog, the Fusion Reactor Blanket Facility, is presented

  3. Te/C nanocomposites for Li-Te Secondary Batteries

    Science.gov (United States)

    Seo, Jeong-Uk; Seong, Gun-Kyu; Park, Cheol-Min

    2015-01-01

    New battery systems having high energy density are actively being researched in order to satisfy the rapidly developing market for longer-lasting mobile electronics and hybrid electric vehicles. Here, we report a new Li-Te secondary battery system with a redox potential of ~1.7 V (vs. Li+/Li) adapted on a Li metal anode and an advanced Te/C nanocomposite cathode. Using a simple concept of transforming TeO2 into nanocrystalline Te by mechanical reduction, we designed an advanced, mechanically reduced Te/C nanocomposite electrode material with high energy density (initial discharge/charge: 1088/740 mA h cm-3), excellent cyclability (ca. 705 mA h cm-3 over 100 cycles), and fast rate capability (ca. 550 mA h cm-3 at 5C rate). The mechanically reduced Te/C nanocomposite electrodes were found to be suitable for use as either the cathode in Li-Te secondary batteries or a high-potential anode in rechargeable Li-ion batteries. We firmly believe that the mechanically reduced Te/C nanocomposite constitutes a breakthrough for the realization and mass production of excellent energy storage systems.

  4. The quadrupole interaction of 125Te and 129I in polycrystalline Te and in Te single crystals

    International Nuclear Information System (INIS)

    Langouche, G.; Rossum, M. van; Schmidt, K.P.; Coussement, R.

    1975-01-01

    Single crystals as hosts for Te and I sources were used in a study of Te. The Moessbauer spectra of 125 Te and 129 I in polycrystalline Te at liquid He temperature are given. Also presented are the Moessbauer spectra of 125 Te in a Te single crystal for the gamma ray parallel to the c-axis and perpendicular to the c-axis of the crystal at liquid He temperature. (Z.S.)

  5. Research into the electrical property variation of undoped CdTe and ZnTe crystals grown under Te-rich conditions

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yadong, E-mail: xyd220@nwpu.edu.cn; Liu, Hang; He, Yihui; Yang, Rui; Luo, Lin; Jie, Wanqi

    2014-11-05

    Highlights: • Conductivity type and resistivity of undoped Te-rich ZnTe and CdTe are different. • Te{sub i} and V{sub Zn} as the dominant defects account for the p-type low resistivity ZnTe. • Te{sub Cd} as the principle defect leading to the light n-type high resistivity CdTe. • DAP and eA peaks dominate the luminescence with their intensities anti-correlated. - Abstract: Both undoped ZnTe and CdTe bulk single crystals are grown under Te-saturated conditions from the solution and melt, respectively. To give an insight into the variation of the electrical properties, the defects structures in both tellurides are discussed. According to the actual growth velocities and the entire cooling history, tellurium interstitials (Te{sub i}) and Zinc vacancies (V{sub Zn}) are proposed as the dominant grown-in defects, account for the low resistivity of p-type ZnTe. However, relatively high pulling rates and slow cooling-down processes result in tellurium anti-sites (Te{sub Cd}) as the principle grown-in defects, leading to the high resistivity of light n-type CdTe. Further low-temperature (8.6 K) photoluminescence spectra of both tellurides are obtained. The donor–acceptor pair (DAP) and recombination of free electron to neutral acceptor (eA) dominate the luminescence, however, with their intensities are anti-correlated. eA is superior to DAP in undoped Te-rich ZnTe, suggests a high concentration of Te{sub i} or V{sub Zn}. On the contrary, DAP is the principal emission for undoped Te-rich CdTe. In addition, V-line is clearly identified in undoped Te-rich ZnTe, which possibly associated with V{sub Zn} or close Frenkel pair V{sub Zn}–Zn{sub i}.

  6. Surface composition of Cd{sub 1–x}Fe(Mn){sub x}Te{sub 1–y}Se{sub y} systems exposed to air

    Energy Technology Data Exchange (ETDEWEB)

    Bundaleski, Nenad [University of Belgrade–Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia); Universidade Nova de Lisboa–Faculdade de Ciências e Tecnologia, Quinta da Torre, 2829–516 Caparica (Portugal); Radisavljević, Ivana, E-mail: iva@vin.bg.ac.rs [University of Belgrade–Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia); Trigueiro, João [Universidade Nova de Lisboa–Faculdade de Ciências e Tecnologia, Quinta da Torre, 2829–516 Caparica (Portugal); Tolstogouzov, Alexander [Universidade Nova de Lisboa–Faculdade de Ciências e Tecnologia, Quinta da Torre, 2829–516 Caparica (Portugal); Ryazan State Radio Engineering University, Gagarin 59/1, 390005 Ryazan (Russian Federation); Rakočević, Zlatko; Medić, Mirjana [University of Belgrade–Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia); Teodoro, Orlando M.N.D. [Universidade Nova de Lisboa–Faculdade de Ciências e Tecnologia, Quinta da Torre, 2829–516 Caparica (Portugal); Romčević, Nebojša [University of Belgrade–Institute of Physics, Pregrevica 118, 11000 Belgrade (Serbia); Ivanović, Nenad [University of Belgrade–Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia)

    2017-03-01

    Using X–ray induced Photoelectron Spectroscopy, Time–of–Flight Secondary Ion Mass Spectrometry and Atomic Force Microscopy we have investigated elemental composition, structure and oxidation process taking place at the surfaces of polycrystalline Cd{sub 0.99}Fe{sub 0.01}Te{sub 0.97}Se{sub 0.03} and Cd{sub 0.95}Mn{sub 0.05}Te{sub 0.97}Se{sub 0.03} systems stored in ambient conditions. The surface oxidation destroys the native CdTe matrix and provokes substantial atomic rearrangement in the first few atomic layers. The near–surface region of both systems is enriched in Cd and to some extent Te–deficient, but the surface structure, morphology and the native oxide composition are all found to be considerably different. In Cd{sub 0.99}Fe{sub 0.01}Te{sub 0.97}Se{sub 0.03} system both Fe and Se dopants diffuse into the bulk and oxidation of its surface results in formation of a thin CdTeO{sub 3} layer which covers the CdTe matrix. In Cd{sub 0.95}Mn{sub 0.05}Te{sub 0.97}Se{sub 0.03} system oxygen–rich atmosphere triggers Mn and Se out–diffusion and the nonuniform oxide layer predominantly consists of MnO and a small amount of Te–oxide which both lay underneath a thin layer of metallic Cd segregated at the top of the surface. - Highlights: • Nature of the CdFe(Mn)TeSe surfaces exposed to air is substantially different. • Near–surface region is enriched in Cd and to some extent Te–deficient. • Presence of Mn drastically changes the surface oxidation conditions. • The surface oxidation in ambient conditions undergoes different mechanisms. • Oxygen triggers Mn out–diffusion, while Fe diffuses into the bulk.

  7. A thermodynamic stability of bulk and epitaxial CdHgTe, ZnHgTe and MnHgTe solid solutions

    International Nuclear Information System (INIS)

    Dejbuk, V.G.; Dremlyuzhenko, S.G.; Ostapov, S.Eh.

    2005-01-01

    A thermodynamics of Cd 1-x Hg x Te, Zn x Hg 1-x Te and Mg x Hg 1-x Te alloys has been investigated for a delta-lattice parameter model. The phase diagrams obtained show the stability of Cd 1-x Hg x Te, Zn x Hg 1-x Te in the whole range of compositions, alongside with a miscibility gap for Mn x Hg 1-x Te being of 0.35 x Hg 1-x Te/CdTe and Mn x Hg 1-x Te/Cd 0.96 Zn 0.04 Te epitaxial films result in lowering critical temperatures and narrowing the miscibility gap [ru

  8. Near-infrared emission bands of TeH and TeD

    Science.gov (United States)

    Fink, E. H.; Setzer, K. D.; Ramsay, D. A.; Vervloet, M.

    1989-11-01

    High-resolution emission spectra of TeH and TeD have been obtained in the region 4200 to 3600 cm -1 using a Bomem DA3.002 Fourier transform spectrometer. Analyses are given for the 0-0 and 1-1 bands of the X 22Π{1}/{2}-X 12Π{3}/{2} system of TeH and for the 0-0 band of TeD. In addition the 2-0 vibrational overtone bands of 130TeH, 128TeH, and 126TeH are observed and analyzed. Accurate molecular constants are given for the first time.

  9. Unified TeV scale picture of baryogenesis and dark matter.

    Science.gov (United States)

    Babu, K S; Mohapatra, R N; Nasri, Salah

    2007-04-20

    We present a simple extension of the minimal supersymmetric standard model which provides a unified picture of cosmological baryon asymmetry and dark matter. Our model introduces a gauge singlet field N and a color triplet field X which couple to the right-handed quark fields. The out-of-equilibrium decay of the Majorana fermion N mediated by the exchange of the scalar field X generates adequate baryon asymmetry for MN approximately 100 GeV and MX approximately TeV. The scalar partner of N (denoted N1) is naturally the lightest SUSY particle as it has no gauge interactions and plays the role of dark matter. The model is experimentally testable in (i) neutron-antineutron oscillations with a transition time estimated to be around 10(10)sec, (ii) discovery of colored particles X at LHC with mass of order TeV, and (iii) direct dark matter detection with a predicted cross section in the observable range.

  10. Conceptual design and neutronics analyses of a fusion reactor blanket simulation facility

    International Nuclear Information System (INIS)

    Beller, D.E.

    1986-01-01

    A new conceptual design of a fusion reactor blanket simulation facility was developed. This design follows the principles that have been successfully employed in the Purdue Fast Breeder Blanket Facility (FBBR), because experiments conducted in it have resulted in the discovery of deficiencies in neutronics prediction methods. With this design, discrepancies between calculation and experimental data can be fully attributed to calculation methods because design deficiencies that could affect results are insignificant. Inelastic scattering cross sections are identified as a major source of these discrepancies. The conceptual design of this FBBR analog, the fusion reactor blanket facility (FRBF), is presented. Essential features are a cylindrical geometry and a distributed, cosine-shaped line source of 14-MeV neutrons. This source can be created by sweeping a deuteron beam over an elongated titanium-tritide target. To demonstrate that the design of the FRBF will not contribute significant deviations in experimental results, neutronics analyses were performed: results of comparisons of 2-dimensional to 1-dimensional predictions are reported for two blanket compositions. Expected deviations from 1-D predictions which are due to source anisotropy and blanket asymmetry are minimal. Thus, design of the FRBF allows simple and straightforward interpretation of the experimental results, without a need for coarse 3-D calculations

  11. Nuclear structure from radioactive decay

    International Nuclear Information System (INIS)

    Wood, J.L.

    1991-01-01

    This report discusses nuclear structure from radioactive decay of the following: Neutron-Deficient Iridium Isotopes; Neutron-Deficient Platinum Isotopes; Neutron-Deficient Gold Isotopes; Neutron-Deficient Mercury Isotopes; Neutron-Deficient Thallium Isotopes; Neutron-Deficient Lead Isotopes; Neutron-Deficient Samarium Isotopes; Neutron-Deficient Promethium Isotopes; Neutron-Deficient Neodymium Isotopes; and Neutron-Deficient Praseodymium Isotopes. Also discussed are Nuclear Systematics and Models

  12. PbTe mechanosynthesis from PbO and Te

    International Nuclear Information System (INIS)

    Rojas-Chavez, Hugo; Diaz-de la Torre, Sebastian; Jaramillo-Vigueras, David; Plascencia, Gabriel

    2009-01-01

    Experimental results concerning the mechanosynthesis (MSY), of PbTe from the PbO-Te powder system, at room temperature an atmospheric conditions are reported. XRD results for samples milled for and after 5.4 ks only show PbTe diffraction peaks; neither Te nor PbO or any other solid phase were detected. Particle size and morphology, was followed by SEM observations. Phase evolution and quantification was monitored by Rietveld refinements of the X-ray diffraction data. It was found that the use of lead oxide as a component of the mechanosynthesis system reduces milling time with respect to the Pb-Te metallic system with mechanical alloying.

  13. n-(CdMgTe/CdTe)/(p-(CdTe/ZnCdTe/ZnTe)/p-GaAs heterostructure diode for photosensor applications

    Science.gov (United States)

    Yahia, I. S.; AlFaify, S.; Abutalib, M. M.; Chusnutdinow, S.; Wojtowicz, T.; Karczewski, G.; Yakuphanoglu, F.; Al-Bassam, A.; El-Naggar, A. M.; El-Bashir, S. M.

    2016-05-01

    High quality n-(CdMgTe:I/n-CdTe:I)/(p-CdTe:N/p-ZnCdTe:N/p-ZnTe:N)/p-GaAs heterojunction diodes have been fabricated by molecular beam epitaxial growth. The illumination effect on the complex impedance and conductivity of heterostructure diode was investigated. The illumination intensities were taken up to the 200 mW/cm2 with frequency range of 42 Hz to 1 MHz. The observed real and imaginary parts of the complex impedance were strongly dependent on the illumination frequency. The inverse relation was observed between the illumination intensity and the complex impedance. The relaxation mechanism of the diode was analyzed by the Cole-Cole plots. The radius of the Cole-Cole curve decreases with increasing illumination intensity. This suggests a mechanism of illumination dependent on the relaxation process. It is also found that the conductivity increases linearly with increasing the illumination intensity. We can conclude that the new design heterostructure diode in our work is a good candidate in photodetector and optoelectronic applications.

  14. Detection of gamma-neutron radiation by solid-state scintillation detectors. Detection of gamma-neutron radiation by novel solid-state scintillation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ryzhikov, V.; Grinyov, B.; Piven, L.; Onyshchenko, G.; Sidletskiy, O. [Institute for Scintillation Materials of the NAS of Ukraine, Kharkov, (Ukraine); Naydenov, S. [Institute for Single Crystals of the National Academy of Sciences of Ukraine, Kharkov, (Ukraine); Pochet, T. [DETEC-Europe, Vannes (France); Smith, C. [Naval Postgraduate School, Monterey, CA (United States)

    2015-07-01

    It is known that solid-state scintillators can be used for detection of both gamma radiation and neutron flux. In the past, neutron detection efficiencies of such solid-state scintillators did not exceed 5-7%. At the same time it is known that the detection efficiency of the gamma-neutron radiation characteristic of nuclear fissionable materials is by an order of magnitude higher than the efficiency of detection of neutron fluxes alone. Thus, an important objective is the creation of detection systems that are both highly efficient in gamma-neutron detection and also capable of exhibiting high gamma suppression for use in the role of detection of neutron radiation. In this work, we present the results of our experimental and theoretical studies on the detection efficiency of fast neutrons from a {sup 239}Pu-Be source by the heavy oxide scintillators BGO, GSO, CWO and ZWO, as well as ZnSe(Te, O). The most probable mechanism of fast neutron interaction with nuclei of heavy oxide scintillators is the inelastic scattering (n, n'γ) reaction. In our work, fast neutron detection efficiencies were determined by the method of internal counting of gamma-quanta that emerge in the scintillator from (n, n''γ) reactions on scintillator nuclei with the resulting gamma energies of ∼20-300 keV. The measured efficiency of neutron detection for the scintillation crystals we considered was ∼40-50 %. The present work included a detailed analysis of detection efficiency as a function of detector and area of the working surface, as well as a search for new ways to create larger-sized detectors of lower cost. As a result of our studies, we have found an unusual dependence of fast neutron detection efficiency upon thickness of the oxide scintillators. An explanation for this anomaly may involve the competition of two factors that accompany inelastic scattering on the heavy atomic nuclei. The transformation of the energy spectrum of neutrons involved in the (n, n

  15. Calculation of neutron fluence to dose equivalent conversion coefficients using GEANT4; Calculo de coeficientes de fluencia de neutrons para equivalente de dose individual utilizando o GEANT4

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Rosane M.; Santos, Denison de S.; Queiroz Filho, Pedro P. de; Mauricio, CLaudia L.P.; Silva, Livia K. da; Pessanha, Paula R., E-mail: rosanemribeiro@oi.com.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2014-07-01

    Fluence to dose equivalent conversion coefficients provide the basis for the calculation of area and personal monitors. Recently, the ICRP has started a revision of these coefficients, including new Monte Carlo codes for benchmarking. So far, little information is available about neutron transport below 10 MeV in tissue-equivalent (TE) material performed with Monte Carlo GEANT4 code. The objective of this work is to calculate neutron fluence to personal dose equivalent conversion coefficients, H{sub p} (10)/Φ, with GEANT4 code. The incidence of monoenergetic neutrons was simulated as an expanded and aligned field, with energies ranging between thermal neutrons to 10 MeV on the ICRU slab of dimension 30 x 30 x 15 cm{sup 3}, composed of 76.2% of oxygen, 10.1% of hydrogen, 11.1% of carbon and 2.6% of nitrogen. For all incident energy, a cylindrical sensitive volume is placed at a depth of 10 mm, in the largest surface of the slab (30 x 30 cm{sup 2}). Physic process are included for neutrons, photons and charged particles, and calculations are made for neutrons and secondary particles which reach the sensitive volume. Results obtained are thus compared with values published in ICRP 74. Neutron fluence in the sensitive volume was calculated for benchmarking. The Monte Carlo GEANT4 code was found to be appropriate to calculate neutron doses at energies below 10 MeV correctly. (author)

  16. Use of INAA to study the interaction between Se and Te in cells of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Czauderna, M.; Turska, M.; Sierokowska, S.; Smolinski, S.

    1996-01-01

    The differences in the effects of inorganic Se (IV and VI) compounds and seleno-cystine [(CySe) 2 ] on the Te (as Na 2 TeO 3 ) uptake by the yeast, Saccharomyces cerevisiae, has been studied. Se, Te, Ag, Zn, Fe and Co contents of the cells were measured by instrumental neutron activation analysis. For the determination of the Ag content, the monostandard method was applied as the analytical method. The contents of other elements were determined by comparison with standards having similar amounts of the determined element as the sample. Results obtained show that an antagonist interaction occurs between SeO 2 and Te. There was a significant increase in the concentration of Se and Te when the yeast was incubated in the medium containing (CySe) 2 and Te. (CySe) 2 markedly increased the Ag content of cells, especially within the first 8 h of incubation. The low level of SeO 2 in the medium are the exterior factor which produce an observable increase of the Ag concentration in the cells. The higher level of SeO 2 in the medium causes a long-term marked increase in the Ag content of the cells. The uptake yield of Ag also increased in the presence of (NH 4 ) 2 SeO 4 in the medium. The Te supply produced a significant enhancement in the Ag content of the cells during the initial 8 h of incubation. The presence of Se and/or Te in the medium causes change in the intracellular Zn, Fe and Co levels. (author)

  17. Partial Pressures of Te2 and Thermodynamic Properties of Ga-Te System

    Science.gov (United States)

    Su, Ching-Hua; Curreri, Peter A. (Technical Monitor)

    2001-01-01

    The partial pressures of Te2 in equilibrium with Ga(1-x)Te(x) samples were measured by optical absorption technique from 450 to 1100 C for compositions, x, between 0.333 and 0.612. To establish the relationship between the partial pressure of Te, and the measured optical absorbance, the calibration runs of a pure Te sample were also conducted to determine the Beer's Law constants. The partial pressures of Te2 in equilibrium with the GaTe(s) and Ga2Te3(s)compounds, or the so-called three-phase curves, were established. These partial pressure data imply the existence of the Ga3Te4(s) compound. From the partial pressures of Te2 over the Ga-Te melts, partial molar enthalpy and entropy of mixing for Te were derived and they agree reasonable well with the published data. The activities of Te in the Ga-Te melts were also derived from the measured partial pressures of Te2. These data agree well with most of the previous results. The possible reason for the high activity of Te measured for x less than 0.60 is discussed.

  18. Calculation of neutron fluence to dose equivalent conversion coefficients using GEANT4

    International Nuclear Information System (INIS)

    Ribeiro, Rosane M.; Santos, Denison de S.; Queiroz Filho, Pedro P. de; Mauricio, CLaudia L.P.; Silva, Livia K. da; Pessanha, Paula R.

    2014-01-01

    Fluence to dose equivalent conversion coefficients provide the basis for the calculation of area and personal monitors. Recently, the ICRP has started a revision of these coefficients, including new Monte Carlo codes for benchmarking. So far, little information is available about neutron transport below 10 MeV in tissue-equivalent (TE) material performed with Monte Carlo GEANT4 code. The objective of this work is to calculate neutron fluence to personal dose equivalent conversion coefficients, H p (10)/Φ, with GEANT4 code. The incidence of monoenergetic neutrons was simulated as an expanded and aligned field, with energies ranging between thermal neutrons to 10 MeV on the ICRU slab of dimension 30 x 30 x 15 cm 3 , composed of 76.2% of oxygen, 10.1% of hydrogen, 11.1% of carbon and 2.6% of nitrogen. For all incident energy, a cylindrical sensitive volume is placed at a depth of 10 mm, in the largest surface of the slab (30 x 30 cm 2 ). Physic process are included for neutrons, photons and charged particles, and calculations are made for neutrons and secondary particles which reach the sensitive volume. Results obtained are thus compared with values published in ICRP 74. Neutron fluence in the sensitive volume was calculated for benchmarking. The Monte Carlo GEANT4 code was found to be appropriate to calculate neutron doses at energies below 10 MeV correctly. (author)

  19. Installation and testing of an optimized epithermal neutron beam at the Brookhaven Medical Research Reactor (BMRR)

    Energy Technology Data Exchange (ETDEWEB)

    Fairchild, R.G.; Kalef-Ezra, J.; Saraf, S.K.; Fiarman, S.; Ramsey, E.; Wielopolski, L.; Laster, B.; Wheeler, F. (Brookhaven National Lab., Upton, NY (USA); Ioannina Univ. (Greece); Brookhaven National Lab., Upton, NY (USA); State Univ. of New York, Stony Brook, NY (USA). Health Science Center; Brookhaven National Lab., Upton, NY (USA); EG and G Idaho, Inc., Idaho Falls, ID (USA))

    1989-01-01

    Various calculations indicate that an optimized epithermal neutron beam can be produced by moderating fission neutrons either with a combination of Al and D{sub 2}O, or with Al{sub 2}O{sub 3}. We have designed, installed and tested an Al{sub 2}O{sub 3} moderated epithermal neutron beam at the Brookhaven Medical Research Reactor (BMRR). The epithermal neutron fluence rate of 1.8 {times} 10{sup 9} n/cm{sup 2}-sec produces a peak thermal neutron fluence rate of 1.9 to 2.8 {times} 10{sup 9} n/cm{sup 2}-sec in a tissue equivalent (TE) phantom head, depending on the configuration. Thus a single therapy treatment of 5 {times} 10{sup 12} n/cm{sup 2} can be delivered in 30--45 minutes. All irradiation times are given for a BMRR power of 3 MW, which is the highest power which can be delivered continuously. 18 refs., 8 figs., 4 tabs.

  20. Dose distributions in thorax inhomogeneity for fast neutron beam from NIRS cyclotron

    International Nuclear Information System (INIS)

    Kutsutani-Nakamura, Yuzuru; Furukawa, Shigeo; Iinuma, T.A.; Kawashima, Katsuhiro; Hoshino, Kazuo; Hiraoka, Takeshi; Maruyama, Takashi; Sakashita, Kunio; Tsunemoto, Hiroshi

    1990-01-01

    The power law tissue-air ratio (TAR) method developed by Batho appears to be practical use for inhomogeneity corrections to the dose calculated in a layered media for photon beam therapy. The validity was examined in applying the modified power law TAR and the isodose shift methods to the dose calculation in thorax tissue inhomogeneity containing the boundary region for fast neutron beam. The neutron beam is produced by bombarding a thick beryllium target with 30 MeV deuterons. Lung phantom was made of granulated tissue equivalent plastic, which resulted in density of 0.30 and 0.60 g/cm 3 . Depth dose distributions for neutron beam were measured in thorax phantom by an air-filled cylindrical ionization chamber with TE plastic wall. The power law TAR method considering TAR of zero depth at boundary was compared with the measured data and a good result was obtained that the calculated dose was within ±3 % against the measured. But the isodose shift method is not so good for dose calculation in thorax tissue inhomogeneity using fast neutron beam. (author)

  1. Infrared and near infrared emission spectra of TeH and TeD

    Science.gov (United States)

    Yu, Shanshan; Shayesteh, Alireza; Fu, Dejian; Bernath, Peter F.

    2005-04-01

    The vibration-rotation emission spectra for the X2Π ground state and the near infrared emission spectra of the X2Π 1/2- X2Π 3/2 system of the TeH and TeD free radicals have been measured at high resolution using a Fourier transform spectrometer. TeH and TeD were generated in a tube furnace with a DC discharge of a flowing mixture of argon, hydrogen (or deuterium), and tellurium vapor. In the infrared region, for the X2Π 3/2 spin component we observed the 1-0, 2-1, and 3-2 vibrational bands for most of the eight isotopologues of TeH and the 1-0 and 2-1 bands for three isotopologues of TeD. For the X2Π 1/2- X2Π 3/2 transition, we observed the 0-0 and 1-1 bands for TeH and the 0-0, 1-1, and 2-2 bands for TeD. Except for a few lines, the tellurium isotopic shift was not resolved for the X2Π 1/2- X2Π 3/2 transitions of TeH and TeD. Local perturbations with Δ v = 2 between the two spin components of the X2Π state of TeH were found: X2Π 1/2, v = 0 with X2Π 3/2, v = 2; X2Π 1/2, v = 1 with X2Π 3/2, v = 3. The new data were combined with the previous data from the literature and two kinds of fits (Hund's case (a) and Hund's case (c)) were carried out for each of the 10 observed isotopologues: 130TeD, 128TeD, 126TeD, 130TeH, 128TeH, 126TeH, 125TeH, 124TeH, 123TeH, and 122TeH.

  2. Extraction of the 1S0 neutron-neutron scattering length from a kinematically-complete n-d breakup experiment at TUNL

    International Nuclear Information System (INIS)

    Gonzalez Trotter, D. E.; Tornow, W.; Howell, C. R.; Salinas, F.; Walter, R. L.; Witalea, H.

    1999-01-01

    The 1 S 0 neutron-neutron (nn) scattering length's currently accepted value (a nn =-18.6±0.3 fm) is derived exclusively from two π - -d capture-reaction experiments, in disagreement with the average -16.7±0.5 fm extracted from kinematically-complete nd breakup experiments. This discrepancy may be due to deficiencies in the analyses of n-d breakup data and/or three-nucleon force (3NF) effects. A kinematically-complete n+d→n 1 +n 2 +p breakup experiment at an incident neutron energy of 13.0 MeV was performed recently at TUNL. The value of a nn was extracted from the direct comparison of experimental and rigorously-calculated theoretical nd breakup differential cross sections at four production angles of the nn pair. Using modern nucleon-nucleon potential models in the three-nucleon cross-section calculations we obtained a nn =-18.7±0.6 fm, in agreement with the π - -d result. We found no significant effect due to 3NFs on our a nn value

  3. Neutronic calculations for the conversion of the University of Florida Training Reactor from HEU to LEU fuel

    International Nuclear Information System (INIS)

    Dugan, E.T.; Diaz, N.J.; Kniedler, G.S.

    1983-01-01

    plate-type fuel. A final reason for converting to the SPERT fuel is related to a desire to upgrade the UFTR from a 100 to a 500 kw facility. Such a change would be difficult with the current aluminum-uranium alloy plate fuel since warping of the plates has been experienced at the 100 kw power level. A motivating force in the proposed UFTR conversion is the existence of the SPERT fuel in-house at the University of Florida (under a DOE agreement) and the DOE's encouragement to pursue the described conversion. The purpose of this paper is to present the results of detailed neutronic investigations performed as part of the feasibility study for the UFTR conversion from HEU to LEU fuel. These neutronics studies included two phases. In the first phase, the efforts were directed primarily towards finding a satisfactory metal-to-water ratio for the SPERT fuel. An acceptable metal-to-water ratio has to satisfy the following neutronics criteria: 1. The neutron multiplication factor, or k eff for the unrodded UFTR must lie in the range of 1.03 to 1.09 both for te current power limit of 100 kw and also for the proposed upgraded rating of 500 kw. 2. The system must be in an under moderated state. 3. Reactivity coefficients and other safety-related neutronics parameters (e.g. effective delayed neutron fraction and prompt neutron lifetime) must be such that current UFTR safety levels are either maintained or enhanced. For the Phase studies, the only permanent UFTR structural modification allowed is the insertion of new grid assemblies into the existing fuel boxes to hold the the cylindrical SPERT fuel in place. The Phase 2 neutronic studies examined the effects of certain additional UFTR structural changes using the metal-to-water ratio lattice determined in the Phase studies. These changes included systematic alterations in certain region thicknesses and compositions. Te primary intention of the Phase 2 studies was to optimize the peak thermal neutron flux level in the UFTR while

  4. Neutronic calculations for the conversion of the University of Florida Training Reactor from HEU to LEU fuel

    Energy Technology Data Exchange (ETDEWEB)

    Dugan, E T; Diaz, N J [Department of Nuclear Engineering Sciences, University of Florida, Gainesville, FL (United States); Kniedler, G S [Reactor Analysis Group, TVA, Chattanooga, TN (United States)

    1983-09-01

    the plate-type fuel. A final reason for converting to the SPERT fuel is related to a desire to upgrade the UFTR from a 100 to a 500 kw facility. Such a change would be difficult with the current aluminum-uranium alloy plate fuel since warping of the plates has been experienced at the 100 kw power level. A motivating force in the proposed UFTR conversion is the existence of the SPERT fuel in-house at the University of Florida (under a DOE agreement) and the DOE's encouragement to pursue the described conversion. The purpose of this paper is to present the results of detailed neutronic investigations performed as part of the feasibility study for the UFTR conversion from HEU to LEU fuel. These neutronics studies included two phases. In the first phase, the efforts were directed primarily towards finding a satisfactory metal-to-water ratio for the SPERT fuel. An acceptable metal-to-water ratio has to satisfy the following neutronics criteria: 1. The neutron multiplication factor, or k{sub eff} for the unrodded UFTR must lie in the range of 1.03 to 1.09 both for te current power limit of 100 kw and also for the proposed upgraded rating of 500 kw. 2. The system must be in an under moderated state. 3. Reactivity coefficients and other safety-related neutronics parameters (e.g. effective delayed neutron fraction and prompt neutron lifetime) must be such that current UFTR safety levels are either maintained or enhanced. For the Phase studies, the only permanent UFTR structural modification allowed is the insertion of new grid assemblies into the existing fuel boxes to hold the the cylindrical SPERT fuel in place. The Phase 2 neutronic studies examined the effects of certain additional UFTR structural changes using the metal-to-water ratio lattice determined in the Phase studies. These changes included systematic alterations in certain region thicknesses and compositions. Te primary intention of the Phase 2 studies was to optimize the peak thermal neutron flux level in the

  5. Possibility of hypothetical stable micro black hole production at future 100 TeV collider

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, A.V. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Lomonosov Moscow State University, Physics Department, Moscow (Russian Federation); Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Pshirkov, M.S. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow (Russian Federation); Pushchino Radio Astronomy Observatory, P.N. Lebedev Physical Institute, Pushchino (Russian Federation)

    2017-12-15

    We study the phenomenology of TeV-scale black holes predicted in theories with large extra dimensions, under the further assumption that they are absolutely stable. Our goal is to present an exhaustive analysis of safety of the proposed 100 TeV collider, as it was done in the case of the LHC. We consider the theories with different number of extra dimensions and identify those for which a possible accretion to macroscopic size would have timescales shorter than the lifetime of the Solar system. We calculate the cross sections of the black hole production at the proposed 100 TeV collider, the fraction of the black holes trapped inside the Earth and the resulting rate of capture inside the Earth via an improved method. We study the astrophysical consequences of stable micro black holes existence, in particular its influence on the stability of white dwarfs and neutron stars. We obtain constraints for the previously unexplored range of higher-dimensional Planck mass values. Several astrophysical scenarios of the micro black hole production, which were not considered before, are taken into account. Finally, using the astrophysical constraints we consider the implications for future 100 TeV terrestrial experiments. We exclude the possibility of the charged stable micro black holes production. (orig.)

  6. Electrical properties of MIS devices on CdZnTe/HgCdTe

    Science.gov (United States)

    Lee, Tae-Seok; Jeoung, Y. T.; Kim, Hyun Kyu; Kim, Jae Mook; Song, Jinhan; Ann, S. Y.; Lee, Ji Y.; Kim, Young Hun; Kim, Sun-Ung; Park, Mann-Jang; Lee, S. D.; Suh, Sang-Hee

    1998-10-01

    In this paper, we report the capacitance-voltage (C-V) properties of metal-insulator-semiconductor (MIS) devices on CdTe/HgCdTe by the metalorganic chemical vapor deposition (MOCVD) and CdZnTe/HgCdTe by thermal evaporation. In MOCVD, CdTe layers are directly grown on HgCdTe using the metal organic sources of DMCd and DiPTe. HgCdTe layers are converted to n-type and the carrier concentration, ND is low 1015 cm-3 after Hg-vacancy annealing at 260 degrees Celsius. In thermal evaporation, CdZnTe passivation layers were deposited on HgCdTe surfaces after the surfaces were etched with 0.5 - 2.0% bromine in methanol solution. To investigate the electrical properties of the MIS devices, the C-V measurement is conducted at 80 K and 1 MHz. C-V curve of MIS devices on CdTe/HgCdTe by MOCVD has shown nearly flat band condition and large hysteresis, which is inferred to result from many defects in CdTe layer induced during Hg-vacancy annealing process. A negative flat band voltage (VFB approximately equals -2 V) and a small hysteresis have been observed for MIS devices on CdZnTe/HgCdTe by thermal evaporation. It is inferred that the negative flat band voltage results from residual Te4+ on the surface after etching with bromine in methanol solution.

  7. Nuclear transition moment measurements of neutron rich nuclei

    Science.gov (United States)

    Starosta, Krzysztof

    2009-10-01

    The Recoil Distance Method (RDM) and related Doppler Shift Attenuation Method (DSAM) are well-established tools for lifetime measurements following nuclear reactions near the Coulomb barrier. Recently, the RDM was implemented at National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University using NSCL/K"oln plunger device and a unique combination of the state-of-the-art instruments available there. Doppler-shift lifetime measurements following Coulomb excitation, knock-out, and fragmentation at intermediate energies of ˜100 MeV/u hold the promise of providing lifetime information for excited states in a wide range of unstable nuclei. So far, the method was used to investigate the collectivity of the neutron-rich ^16,18,20C, ^62,64,66Fe, ^70,72Ni, ^110,114Pd isotopes and also of the neutron-deficient N=Z ^64Ge. A significant fraction of these experiments was performed using NSCL's Segmented Germanium Array instrumented with the Digital Data Acquisition System which enables gamma-ray tracking. The impact of GRETINA and gamma-ray tracking on RDM and DSAM studies of neutron-rich nuclei will be discussed.

  8. Calculations of neutron spectra after neutron-neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, B E [Gettysburg College, Box 405, Gettysburg, PA 17325 (United States); Stephenson, S L [Gettysburg College, Box 405, Gettysburg, PA 17325 (United States); Howell, C R [Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Mitchell, G E [North Carolina State University, Raleigh, NC 27695-8202 (United States); Tornow, W [Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Furman, W I [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Lychagin, E V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Muzichka, A Yu [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Nekhaev, G V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Strelkov, A V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Sharapov, E I [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Shvetsov, V N [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)

    2004-09-01

    A direct neutron-neutron scattering length, a{sub nn}, measurement with the goal of 3% accuracy (0.5 fm) is under preparation at the aperiodic pulsed reactor YAGUAR. A direct measurement of a{sub nn} will not only help resolve conflicting results of a{sub nn} by indirect means, but also in comparison to the proton-proton scattering length, a{sub pp}, shed light on the charge-symmetry of the nuclear force. We discuss in detail the analysis of the nn-scattering data in terms of a simple analytical expression. We also discuss calibration measurements using the time-of-flight spectra of neutrons scattered on He and Ar gases and the neutron activation technique. In particular, we calculate the neutron velocity and time-of-flight spectra after scattering neutrons on neutrons and after scattering neutrons on He and Ar atoms for the proposed experimental geometry, using a realistic neutron flux spectrum-Maxwellian plus epithermal tail. The shape of the neutron spectrum after scattering is appreciably different from the initial spectrum, due to collisions between thermal-thermal and thermal-epithermal neutrons. At the same time, the integral over the Maxwellian part of the realistic scattering spectrum differs by only about 6 per cent from that of a pure Maxwellian nn-scattering spectrum.

  9. Superconducting transition in TlBiTe/sub 2/ and TlTe compounds

    Energy Technology Data Exchange (ETDEWEB)

    Kantser, V G; Popovich, N S; Sidorenko, A S

    1985-10-01

    On the basis of zone structure calculation for TlBiTe/sub 2/ and TlTe it is found that TlBiTe/sub 2/ is a narrow-gap semiconductor and TlTe is a p-metal. At Tsub(c)=0.19 K TlTe is found to experience the superconducting transition. In TlBiTe/sub 2/ superconductivity is not observed to occur up to 0.05 K, since there is a possibility of occupying the high density of states zones because they are remote from actual ones. The earlier discovered superconducting transition in TlBiTe/sub 2/ is inherent in the alien phase of TlTe.

  10. From thermoelectric bulk to nanomaterials: Current progress for Bi2Te3 and CoSb3

    International Nuclear Information System (INIS)

    Peranio, N.; Eibl, O.; Baessler, S.; Nielsch, K.; Klobes, B.; Hermann, R.P.; Daniel, M.; Albrecht, M.; Goerlitz, H.; Pacheco, V.; Bedoya-Martinez, N.; Hashibon, A.; Elsaesser, C.

    2016-01-01

    Bi 2 Te 3 and CoSb 3 based nanomaterials were synthesized and their thermoelectric, structural, and vibrational properties analyzed to assess and reduce ZT-limiting mechanisms. The same preparation and/or characterization methods were applied in the different materials systems. Single-crystalline, ternary p-type Bi 15 Sb 29 Te 56 , and n-type Bi 38 Te 55 Se 7 nanowires with power factors comparable to nanostructured bulk materials were prepared by potential-pulsed electrochemical deposition in a nanostructured Al 2 O 3 matrix. p-type Sb 2 Te 3 , n-type Bi 2 Te 3 , and n-type CoSb 3 thin films were grown at room temperature using molecular beam epitaxy and were subsequently annealed at elevated temperatures. This yielded polycrystalline, single phase thin films with optimized charge carrier densities. In CoSb 3 thin films the speed of sound could be reduced by filling the cage structure with Yb and alloying with Fe yielded p-type material. Bi 2 (Te 0.91 Se 0.09 ) 3 /SiC and (Bi 0.26 Sb 0.74 ) 2 Te 3 /SiC nanocomposites with low thermal conductivities and ZT values larger than 1 were prepared by spark plasma sintering. Nanostructure, texture, chemical composition, as well as electronic and phononic excitations were investigated by X-ray diffraction, nuclear resonance scattering, inelastic neutron scattering, Moessbauer spectroscopy, and transmission electron microscopy. For Bi 2 Te 3 materials, ab-initio calculations together with equilibrium and non-equilibrium molecular dynamics simulations for point defects yielded their formation energies and their effect on lattice thermal conductivity, respectively. Current advances in thermoelectric Bi 2 Te 3 and CoSb 3 based nanomaterials are summarized. Advanced synthesis and characterization methods and theoretical modeling were combined to assess and reduce ZT-limiting mechanisms in these materials. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Gênero, maternidade e deficiência: representação da diversidade = Gender, Maternity and Deficiency: Representation of Diversity

    Directory of Open Access Journals (Sweden)

    Welter, Ivânia

    2008-01-01

    Full Text Available Este artigo é parte de pesquisa realizada no Curso de Serviço Social da Universidade do Oeste de Santa Catarina (UNOESC, Campus de São Miguel do Oeste, tendo como objetivo geral identificar as principais representações sociais de mães cujos filhos têm Síndrome de Down. O interesse pela temática apresentada surgiu a partir de experiências vivenciadas no período de Estágio Curricular, realizado junto à Escola Especial “Viviane” – APAE de São José do Cedro (SC. E, também, pelo fato de o Serviço Social contribuir por intermédio da atuação profissional nas problemáticas ocasionadas pela deficiência mental. O resultado deste trabalho foi constatado através de pesquisa de campo com seis mães que possuem filhos com Síndrome de Down, bem como em referenciais teóricos nos quais foram visualizadas as principais representações sociais que se refletem desde o contato inicial com a deficiência, identificadas através da culpa, negação/aceitação no relacionamento familiar e social e, principalmente, reafirmando a condição histórica e social da mulher/mãe como principal cuidadora do filho com deficiência. Apontamos, dentre as estratégias de enfrentamento da realidade vivenciada pela mulher/mãe, a contribuição de profissionais com preparo técnico, sendo que o assistente social poderá atuar na implantação e implementação de políticas de inclusão social da pessoa com deficiência e sua família

  12. S and Te inter-diffusion in CdTe/CdS hetero junction

    Energy Technology Data Exchange (ETDEWEB)

    Enriquez, J. Pantoja [Cuerpo Academico-Energia y Sustentabilidad, Universidad Politecnica de Chiapas, Eduardo J. Selvas S/N, Col. Magisterial, Tuxtla Gutierrez 29010, Chiapas (Mexico); Gomez Barojas, E. [CIDS-ICUAP, Apdo. Postal 1651, 72000 Puebla (Mexico); Silva Gonzalez, R.; Pal, U. [Instituto de Fisica, Benemerita Universidad Autonoma de Puebla, Puebla (Mexico)

    2007-09-22

    Effects of post formation thermal annealing of the CdTe-CdS device on the inter-diffusion of S and Te at the junction in a substrate configuration device have been studied by Auger electron spectroscopy. While the migration of S and Te atoms increases with annealing temperature, the extent of S diffusion is always higher than the diffusion of Te atoms. Inter-diffusion of S and Te causes the formation of CdTe{sub 1-x}S{sub x} ternary compound at the CdTe-CdS interface. (author)

  13. Astrophysical implications of hypothetical stable TeV-scale black holes

    International Nuclear Information System (INIS)

    Giddings, Steven B.; Mangano, Michelangelo L.

    2008-01-01

    We analyze macroscopic effects of TeV-scale black holes, such as could possibly be produced at the LHC, in what is regarded as an extremely hypothetical scenario in which they are stable and, if trapped inside Earth, begin to accrete matter. We examine a wide variety of TeV-scale gravity scenarios, basing the resulting accretion models on first-principles, basic, and well-tested physical laws. These scenarios fall into two classes, depending on whether accretion could have any macroscopic effect on the Earth at times shorter than the Sun's natural lifetime. We argue that cases with such an effect at shorter times than the solar lifetime are ruled out, since in these scenarios black holes produced by cosmic rays impinging on much denser white dwarfs and neutron stars would then catalyze their decay on time scales incompatible with their known lifetimes. We also comment on relevant lifetimes for astronomical objects that capture primordial black holes. In short, this study finds no basis for concerns that TeV-scale black holes from the LHC could pose a risk to Earth on time scales shorter than the Earth's natural lifetime. Indeed, conservative arguments based on detailed calculations and the best-available scientific knowledge, including solid astronomical data, conclude, from multiple perspectives, that there is no risk of any significance whatsoever from such black holes.

  14. Thermodynamic characterization of Ni3TeO6, Ni2Te3O8 and NiTe2O5

    Science.gov (United States)

    Dawar, Rimpi; Babu, R.; Ananthasivan, K.; Anthonysamy, S.

    2017-09-01

    Measurement of vapour pressure of TeO2(g) over the biphasic mixture Ni3TeO6 (s) + NiO(s) in the temperature range 1143-1272 K was carried out using transpiration-thermogravimetric technique (TTG). Gibbs energy of formation of Ni3TeO6 was obtained from the temperature dependence of vapour pressure of TeO2 (g) generated by the incongruent vapourisation reaction, Ni3TeO6 (s) → NiO(s) + TeO2 (g) + 1/2 O2 in the temperature range 1143-1272 K. An isoperibol type drop calorimeter was used to measure the enthalpy increments of Ni3TeO6, Ni2Te3O8 and NiTe2O5. Thermodynamic functions viz., heat capacity, entropy and Gibbs energy functions of these compounds were derived from the experimentally measured enthalpy increment values. Third-law analysis was carried out to ascertain absence of temperature dependent systematic errors in the measurement of vapour pressure of TeO2 (g). A value of -1265.1 ± 1.5 kJ mol-1 was obtained for Δ Hf,298K o (Ni3TeO6) using third-law analysis.

  15. Highest-order optical phonon-mediated relaxation in CdTe/ZnTe quantum dots

    International Nuclear Information System (INIS)

    Masumoto, Yasuaki; Nomura, Mitsuhiro; Okuno, Tsuyoshi; Terai, Yoshikazu; Kuroda, Shinji; Takita, K.

    2003-01-01

    The highest 19th-order longitudinal optical (LO) phonon-mediated relaxation was observed in photoluminescence excitation spectra of CdTe self-assembled quantum dots grown in ZnTe. Hot excitons photoexcited highly in the ZnTe barrier layer are relaxed into the wetting-layer state by emitting multiple LO phonons of the barrier layer successively. Below the wetting-layer state, the LO phonons involved in the relaxation are transformed to those of interfacial Zn x Cd 1-x Te surrounding CdTe quantum dots. The ZnTe-like and CdTe-like LO phonons of Zn x Cd 1-x Te and lastly acoustic phonons are emitted in the relaxation into the CdTe dots. The observed main relaxation is the fast relaxation directly into CdTe quantum dots and is not the relaxation through either the wetting-layer quantum well or the band bottom of the ZnTe barrier layer. This observation shows very efficient optical phonon-mediated relaxation of hot excitons excited highly in the ZnTe conduction band through not only the ZnTe extended state but also localized state in the CdTe quantum dots reflecting strong exciton-LO phonon interaction of telluride compounds

  16. Insulators for Pb(1-x)Sn(x)Te

    Science.gov (United States)

    Tsuo, Y. H.; Sher, A.

    1981-01-01

    Thin films of LaF3 were e-gun and thermally deposited on several substrates. The e-gun deposited films are fluorine deficient, have high ionic conductivities that persist to 77 K, and high effective dielectric constants. The thermally deposited material tends to be closer to stoichiometric, and have higher effective breakdown field strengths. Thermally deposited LaF3 films with resistivities in excess of 10 to the 12th power ohms - cm were deposited on metal coated glass substrates. The LaF3 films were shown to adhere well to PbSnTe, surviving repeated cycles between room temperature and 77 K. The LaF3 films on GaAs were also studied.

  17. Empty sella syndrome associated with hormone deficiency in adults; Silla turca vacia asociada a disfuncion hormonal en adultos

    Energy Technology Data Exchange (ETDEWEB)

    Oleaga, L.; Paja, M.; Goni, F.; Grande, J.; Grande, D. [Hospital de Basurto. Bilbao (Spain); Merino, M. [Hospital General Yague (Spain); Delgado, A. [Hospital Marques de Valdecilla. Santander (Spain)

    1999-07-01

    The objective of this study was to correlate the magnetic resonance (MR) images in patients with hormone deficiencies with the clinical data and the hormonal status. We studied 11 cases ef empty sella with different peripheral pituitary deficiencies. Hormone levels were determined according to standard laboratory methods. All the patients underwent MR imaging. The studies were carried out with a 1 Tesla superconducting magnet, using the cranial cavity for transmission and reception. Segittal and coronal T1-weighted spin-echo sequences (TR/TE: 600/15 ms), axial T2-weighted spin-echo sequences (TR/TE: 3,500/19/93 ms) and gadolinium-enhanced (=.2 cc/kg body weight) sagital and coronal T1-weighted spin-echo sequences (TR/TE: 600/15 ms) were employed. Six of the patients presented partial or total hypopituitarism associated with the syndrome of inappropriate antidiuretic hormone secretion (SIADH); there was one case of panhypopituitarism without SIADH and four cases of primary hypothyroidism, there of which were associated with pituitary deficiency, MR imaging revealed five cases of partially empty sella with residual pituitary gland on the sella floor and six cases in which the sella was completely empty. This study also identified six cases of normally situated neurohypophysis, another four in which the neurohypophysis could not be identified and one case of ectopic neurohypophysis. MR imaging is the technique of choice in the study of abnormal hypothalamic-pituitary activity. Empty and partially empty sella should be included among the frequent causes of hypopituitarism, although there is no clear relationship between the degree of adenohypophyseal insufficiency and the degree of atrophy of this system as viewed in MR images. In some cases, this entity may be the radiological sign of a phase in the development of an autoimmune inflammatory process involving the pituitary gland. (Author) 16 refs.

  18. Designing Diameter-Modulated Heterostructure Nanowires of PbTe/Te by Controlled Dewetting.

    Science.gov (United States)

    Kumar, Abinash; Kundu, Subhajit; Samantaray, Debadarshini; Kundu, Paromita; Zanaga, Daniele; Bals, Sara; Ravishankar, N

    2017-12-13

    Heterostructures consisting of semiconductors with controlled morphology and interfaces find applications in many fields. A range of axial, radial, and diameter-modulated nanostructures have been synthesized primarily using vapor phase methods. Here, we present a simple wet chemical routine to synthesize heterostructures of PbTe/Te using Te nanowires as templates. A morphology evolution study for the formation of these heterostructures has been performed. On the basis of these control experiments, a pathway for the formation of these nanostructures is proposed. Reduction of a Pb precursor to Pb on Te nanowire templates followed by interdiffusion of Pb/Te leads to the formation of a thin shell of PbTe on the Te wires. Controlled dewetting of the thin shell leads to the formation of cube-shaped PbTe that is periodically arranged on the Te wires. Using control experiments, we show that different reactions parameters like rate of addition of the reducing agent, concentration of Pb precursor and thickness of initial Te nanowire play a critical role in controlling the spacing between the PbTe cubes on the Te wires. Using simple surface energy arguments, we propose a mechanism for the formation of the hybrid. The principles presented are general and can be exploited for the synthesis of other nanoscale heterostructures.

  19. Microstructure analyses and thermoelectric properties of Ag1−xPb18Sb1+yTe20

    International Nuclear Information System (INIS)

    Perlt, S.; Höche, Th.; Dadda, J.; Müller, E.; Bauer Pereira, P.; Hermann, R.; Sarahan, M.; Pippel, E.; Brydson, R.

    2012-01-01

    This study reports microstructural investigations of long-term annealed Ag 1−x Pb m Sb 1+y Te 2+m (m=18, x=y=0, hereinafter referred to as AgPb 18 SbTe 20 ) (Lead–Antimony–Silver–Tellurium, LAST-18) as well as of Ag 1−x Pb 18 Sb 1+y Te 20 , i.e. Ag-deficient and Sb-excess LAST-18 (x≠0,y≠0), respectively. Two different length scales are explored. The micrometer scale was evaluated by SEM to analyze the volume fraction and the number of secondary phases as well as the impact of processing parameters on the homogeneity of bulk samples. For AgPb 18 SbTe 20 , site-specific FIB liftout of TEM lamellae from thermoelectrically characterized samples was accomplished to investigate the structure on the nanometer scale. High-resolution TEM and energy-filtered TEM were performed to reveal shape and size distribution of nanoprecipitates, respectively. A hypothesis concerning the structure–property relationship is set out within the frame of a gradient annealing experiment. This study is completed by results dealing with inhomogeneities on the micrometer scale of Ag 1−x Pb 18 Sb 1+y Te 20 and its electronic properties. Highlights: ► SEM and TEM microstructure investigation of long-term annealed AgPb 18 SbTe 20 . ► SEM and thermoelectric studies on Ag 1−x Pb 18 Sb 1+y Te 20 . ► Discussion concerning structure–property relationship in long-term annealed AgPb 18 SbTe 20 . ► Correlation between Ag 1−x Pb 18 Sb 1+y Te 20 microscale structure and electronic properties.

  20. Laser spectroscopy of cadmium isotopes: probing the nuclear structure between the neutron 50 and 82 shell closures

    CERN Multimedia

    Blaum, K; Stroke, H H; Krieger, A R

    We propose to study the isotopic chain of cadmium with high-resolution laser spectroscopy for the first time. Our goal is to determine nuclear spins, moments and root-mean-square charge radii of ground and isomeric states between the neutron 50 and 82 shell closures, contributing decisively to a better understanding of the nuclear structure in the vicinity of the doubly-magic $^{100}$Sn and $^{132}$Sn. On the neutron-rich side this is expected to shed light on a shell-quenching hypothesis and consequently on the duration of the r-process along the waiting-point nuclei below $^{130}$Cd. On the neutron-deficient side it may elucidate the role of the cadmium isotopes in the rp-process for rapidly accreting neutron stars.

  1. Comprehensive thermodynamic description of the quasiternary system PbTe-GeTe-SnTe

    International Nuclear Information System (INIS)

    Yashina, Lada V.; Leute, Volkmar; Shtanov, Vladimir I.; Schmidtke, Heinrich M.; Neudachina, Vera S.

    2006-01-01

    The equilibrium phase diagram of the quasiternary system PbTe-GeTe-SnTe was studied experimentally in the ranges of spinodal demixing and (solid + liquid) equilibrium by means of X-ray diffraction (XRD), electron microprobe analysis (EMA) and differential thermal analysis (DTA). A model description of the phase diagram was done on the base of composition dependent interaction parameters, which were determined for the solid and the liquid phases. The interaction parameters for the quasibinary systems were recalculated in order to reach better correlation between all experimental data. It was shown that the quasiternary phase diagram can be principally described using the interaction parameters for the quasibinary subsystems, but an additional ternary interaction parameter has also to be considered. The local structure of the quasiternary solid solution is described by a four-particle cluster model. Due to the tendency of the solid solution to demix, the probability of the (GeGeGe)Te cluster was found to be higher and that of the (PbGeGe)Te cluster to be lower than it is expected for the purely statistical distribution of the clusters

  2. Desorption of Te capping layer from ZnTe (100): Auger spectroscopy ...

    African Journals Online (AJOL)

    ... configurations of tellurium Te (c (2x2)) and Te (c (2x1)) are confirmed by scanning tunneling microscopy (STM). Such a study reveals a phase transition from a rich-Te to a poor-Te surface as the annealing temperature increases. Keywords: Zinc Tellure; solar cells; structural properties; optoelectronics; semiconductors.

  3. Study of Te Inclusions in CdMnTe Crystals for Nuclear Detector Applications

    International Nuclear Information System (INIS)

    Babalola, O.S.; Bolotnikov, A.; Groza, M.; Hossain, A.; Egarievwe, S.; James, R.; Burger, A.

    2009-01-01

    The concentration, size and spatial distribution of Te inclusions in the bulk of CdMnTe crystals mined from two batches of ingots were studied. An isolated planar layer decorated with Te inclusions was identified in CdMnTe crystals from the second ingot. The internal electric field of a CMT crystal was probed by infrared (IR) imaging employing Pockels electro-optic effect. The effect of an isolated plane of Te inclusions on the internal electric-field distribution within the CdMnTe crystal was studied. Space charge accumulation around the plane of Te inclusions was observed, which was found to be higher when the detector was reverse-biased. The effects of the plane of Te inclusions on the electric-field distribution within the CdMnTe crystal, and the quality of CdMnTe crystals for nuclear detector applications are discussed.

  4. Differential effect of ionizing radiation on transcription in repair-deficient and repair-proficient mice

    International Nuclear Information System (INIS)

    Munson, G.P.; Woloschak, G.E.

    1990-01-01

    Experiments were designed to examine in vivo changes in total transcription and in the expression of the c-fos gene following whole-body exposure of mice to JANUS fission-spectrum neutrons. Radiation repair-deficient (wst/wst) and -proficient (wst/., C57BL/6 x C3H F1) mice were exposed to JANUS fission-spectrum neutrons calibrated to deliver a gut dose of 50 cGy. Animals were sacrificed less than 10 or at 60 min postirradiation, and gut tissues were removed for study. Our results revealed that, in repair-proficient mice, an immediate depression (relative to untreated control) in total transcription was evident that continued through 1 h postirradiation. Conversely, radiation-sensitive wst/wst mice displayed doubled transcription levels postirradiation. Expression of c-fos was consistently depressed following radiation exposure in control and wst/wst mice. However, the depression of c-fos mRNA was delayed in wst/wst mice relative to controls. These results demonstrate abnormal regulation of transcription and of c-fos mRNA accumulation in repair-deficient wasted mice following exposure to ionizing radiation. In addition, this work documents rapid total transcriptional depression in normal mice following radiation exposure

  5. Solution Grown Se/Te Nanowires: Nucleation, Evolution, and The Role of Triganol Te seeds

    Directory of Open Access Journals (Sweden)

    Shan Xudong

    2009-01-01

    Full Text Available Abstract We have studied the nucleation and growth of Se–Te nanowires (NWs, with different morphologies, grown by a chemical solution process. Through systematic characterization of the Se–Te NW morphology as a function of the Te nanocrystallines (NCs precursor, the relative ratio between Se and Te, and the growth time, a number of significant insights into Se–Te NW growth by chemical solution processes have been developed. Specifically, we have found that: (i the growth of Se–Te NWs can be initiated from either long or short triganol Te nanorods, (ii the frequency of proximal interactions between nanorod tips and the competition between Se and Te at the end of short Te nanorods results in V-shaped structures of Se–Te NWs, the ratio between Se and Te having great effect on the morphology of Se–Te NWs, (iii by using long Te nanorods as seeds, Se–Te NWs with straight morphology were obtained. Many of these findings on Se–Te NW growth can be further generalized and provide very useful information for the rational synthesis of group VI based semiconductor NW compounds.

  6. Structural chemistry and magnetic properties of the perovskite Sr{sub 3}Fe{sub 2}TeO{sub 9}

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yawei; Hunter, Emily C. [Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR (United Kingdom); Battle, Peter D., E-mail: peter.battle@chem.ox.ac.uk [Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR (United Kingdom); Sena, Robert Paria; Hadermann, Joke [EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Avdeev, Maxim [Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234 (Australia); Cadogan, J.M. [School of Physical, Environmental and Mathematical Sciences, UNSW Canberra at the Australian Defence Force Academy, Canberra BC 2610 (Australia)

    2016-10-15

    A polycrystalline sample of perovskite-like Sr{sub 3}Fe{sub 2}TeO{sub 9} has been prepared in a solid-state reaction and studied by a combination of electron microscopy, Mössbauer spectroscopy, magnetometry, X-ray diffraction and neutron diffraction. The majority of the reaction product is shown to be a trigonal phase with a 2:1 ordered arrangement of Fe{sup 3+} and Te{sup 6+} cations. However, the sample is prone to nano-twinning and tetragonal domains with a different pattern of cation ordering exist within many crystallites. Antiferromagnetic ordering exists in the trigonal phase at 300 K and Sr{sub 3}Fe{sub 2}TeO{sub 9} is thus the first example of a perovskite with 2:1 trigonal cation ordering to show long-range magnetic order. At 300 K the antiferromagnetic phase coexists with two paramagnetic phases which show spin-glass behaviour below ~80 K. - Graphical abstract: Sr{sub 3}Fe{sub 2}TeO{sub 9} has a 2:1 ordered arrangement of Fe{sup 3+} and Te{sup 6+} cations over the octahedral sites of a perovskite structure and is antiferromagnetic at room temperature. - Highlights: • 2:1 Cation ordering in a trigonal perovskite. • Magnetically ordered trigonal perovskite. • Intergrowth of nanodomains in perovskite microstructure.

  7. Storage Pool Deficiencies

    Science.gov (United States)

    ... Deficiency Factor V Deficiency Combined FV & FVIII Deficiencies Factor VII Deficiency Factor X Deficiency Factor XI Deficiency Factor ... Deficiency Factor V Deficiency Combined FV & FVIII Deficiencies Factor VII Deficiency Factor X Deficiency Factor XI Deficiency Factor ...

  8. High-lying neutron hole strengths observed in pick-up reactions

    International Nuclear Information System (INIS)

    Gales, S.

    1980-01-01

    Neutron-hole states in orbits well below the Fermi surface have been observed in a number of medium-heavy nuclei from A=90 to 209 using one nucleon pick-up reactions. The excitation energies, angular distributions of such broad and enhanced structures will be discussed. The fragmentation of the neutron-hole strengths as well as the spreading of such simple mode of excitations into more complex states are compared to recent calculations within the quasiparticle-phonon or the single particle-vibration coupling nuclear models. We report on recent measurements of J for inner-hole states in 89 Zr and 115 Sn 119 Sn using the analyzing power of the (p,d) and (d,t) reactions. Large enhancement of cross-sections are observed at high excitation energy in the study of the (p,t) reactions on Zr, Cd, Sn, Te and Sm isotopes. The systematic features of such high-lying excitation are related to the ones observed in one neutron pick-up experiments. The origin of such concentration of two neutron-hole strengths in Cd and Sn isotopes will be discussed. Preliminary results obtained in the study of the (α, 6 He) reaction at 218 MeV incident energy on 90 Zr, 118 Sn and 208 Pb targets are presented and compared to the (p,t) results. Finally the properties of hole-analog states populated in neutron pick-up reactions (from 90 Zr to 208 Pb) will be presented

  9. Neutron--neutron logging

    International Nuclear Information System (INIS)

    Allen, L.S.

    1977-01-01

    A borehole logging tool includes a steady-state source of fast neutrons, two epithermal neutron detectors, and two thermal neutron detectors. A count rate meter is connected to each neutron detector. A first ratio detector provides an indication of the porosity of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two epithermal neutron detectors. A second ratio detector provides an indication of both porosity and macroscopic absorption cross section of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two thermal neutron detectors. By comparing the signals of the two ratio detectors, oil bearing zones and salt water bearing zones within the formation being logged can be distinguished and the amount of oil saturation can be determined. 6 claims, 2 figures

  10. Neutron activation analysis of high-purity zinc

    International Nuclear Information System (INIS)

    Khodzhamberdyeva, A.A.; Usmanova, M.M.; Gil'bert, Eh.N.; Ivanov, I.M.; Yankovskaya, T.A.; Kholyavko, E.P.

    1987-01-01

    The methods of neutron activation analysis of high-purity zinc with preliminary separation of the zinc base using extraction by trialkylbenzylammonium rhodanide in carbon tetrachloride from 0.5-2.0 M nitric acid solutions is developed. Only rhenium is quantitatively extracted together with zinc. Gold, iridium and molybdenum are extracted to 50-60%, and selenium - to 20%. The Na, K, La, Cr, Sc, Co, Cs, Rb, Fe, Zr, Sn, Te, As, Cd, Hf, W, Sb, Sm impurities remain in the aqueous phase. The methods permits to determine the impurities above with detection limits from 1x10 -6 to 4x10 -11 g

  11. Instrumental determination of iodine in milk by neutron activation analysis

    International Nuclear Information System (INIS)

    Isaac Olive, K.; Chatt, A.

    2006-01-01

    Iodine is an essential trace element. It is related to thyroid functions and its deficiency or excess can be harmful. Deficiency of iodine leads to brain damage including cretinism, excess of iodine blocks the thyroid gland ultimately producing iodine deficiency as well. World Health Organization has set a daily iodine intake dose of 150 μg d -1 . Currently there are 740 million people in the world at risk of iodine deficiency disorders; therefore the monitoring of iodine intake is necessary. Although the iodized salt policy has been adopted in many countries, milk is also one of the major natural sources of iodine and it is also the principal food in children. Therefore, the determination of iodine in milk is needed. This work deals with the determination of iodine in milk by neutron activation analysis. Different methods of irradiation-counting are compared in terms of sensitivity and detection limits. The quantification of iodine was calculated using also two methods, the classic relative one and the standardization of k 0 parameter. A brief analysis of the uncertainty sources in the analytical method is also discussed.(Full text)

  12. CuGaTe2-CuAlTe2 system

    International Nuclear Information System (INIS)

    Bodnar', I.V.

    2003-01-01

    The results of studies on the chemical interaction in the CuGaTe 2 -CuAlTe 2 as well as on the thermal and optical properties of the formed solid solutions are presented. It is shown, that continuous number of solid solutions are formed in the CuGaTe 2 -CuAlTe 2 system, which crystallize in the chalcopyrite structure. The diagram of state of this system is plotted. The thermal expansion of these materials is studied through the dilatometric method. The linear dependence of the thermal expansion coefficient on the composition is established. The concentration dependences of the forbidden zone width diverge from the linearity [ru

  13. The influence of the energy distribution of workplace fields on neutron personal dosemeter reading

    International Nuclear Information System (INIS)

    Tanner, R.J.; Thomas, D.J.; Bartlett, D.T.; Hager, L.G.; Horwood, N.A.

    2002-01-01

    Variations in the energy dependence of response of neutron personal dosemeters cause systematic errors in the readings obtained in workplace fields. The magnitude of these errors has been determined theoretically by folding measured and calculated workplace energy distributions with dosemeter response functions, to determine the response of a given personal dosemeter in that field. These results have been analysed with consideration of the dosemeter response to various calibration spectra, and with reference to different workplaces. The dosemeters in the study are discussed in terms of the workplaces for which they can be suitably calibrated. Deficiencies in the published neutron energy distributions are identified

  14. Study of Te Inclusion and Related Point Defects in THM-Growth CdMnTe Crystal

    Science.gov (United States)

    Mao, Yifei; Zhang, Jijun; Min, Jiahua; Liang, Xiaoyan; Huang, Jian; Tang, Ke; Ling, Liwen; Li, Ming; Zhang, Ying; Wang, Linjun

    2018-02-01

    This study establishes a model for describing the interaction between Te inclusions, dislocations and point defects in CdMnTe crystals. The role of the complex environment surrounding the formation of Te inclusions was analyzed. Images of Te inclusions captured by scanning electron microscope and infrared microscope were used to observe the morphology of Te inclusions. The morphology of Te inclusions is discussed in light of crystallography, from the crystal growth temperature at 900°C to the melting temperature of Te inclusions using the traveling heater method. The dislocation nets around Te inclusions were calculated by counting lattice mismatches between the Te inclusions and the bulk CdMnTe at 470°C. The point defects of Te antisites were found to be gathered around Te inclusions, with dislocation climb during the cooling phase of crystal growth from 470°C to room temperature. The Te inclusions, dislocation nets and surrounding point defects are considered to be an entirety for evaluating the effect of Te inclusions on CdMnTe detector performance, and an effective mobility-lifetime product (μτ) was obtained.

  15. Pulsar TeV Halos Explain the Diffuse TeV Excess Observed by Milagro.

    Science.gov (United States)

    Linden, Tim; Buckman, Benjamin J

    2018-03-23

    Milagro observations have found bright, diffuse TeV emission concentrated along the galactic plane of the Milky Way. The intensity and spectrum of this emission is difficult to explain with current models of hadronic γ-ray production, and has been named the "TeV excess." We show that TeV emission from pulsars naturally explains this excess. Recent observations have detected "TeV halos" surrounding pulsars that are either nearby or particularly luminous. Extrapolating this emission to the full population of Milky Way pulsars indicates that the ensemble of "subthreshold" sources necessarily produces bright TeV emission diffusively along the Milky Way plane. Models indicate that the TeV halo γ-ray flux exceeds that from hadronic γ rays above an energy of ∼500  GeV. Moreover, the spectrum and intensity of TeV halo emission naturally matches the TeV excess. Finally, we show that upcoming HAWC observations will resolve a significant fraction of the TeV excess into individual TeV halos, conclusively confirming, or ruling out, this model.

  16. Neutronics of pulsed spallation neutron sources

    CERN Document Server

    Watanabe, N

    2003-01-01

    Various topics and issues on the neutronics of pulsed spallation neutron sources, mainly for neutron scattering experiments, are reviewed to give a wide circle of readers a better understanding of these sources in order to achieve a high neutronic performance. Starting from what neutrons are needed, what the spallation reaction is and how to produce slow-neutrons more efficiently, the outline of the target and moderator neutronics are explained. Various efforts with some new concepts or ideas have already been devoted to obtaining the highest possible slow-neutron intensity with desired pulse characteristics. This paper also reviews the recent progress of such efforts, mainly focused on moderator neutronics, since moderators are the final devices of a neutron source, which determine the source performance. Various governing parameters for neutron-pulse characteristics such as material issues, geometrical parameters (shape and dimensions), the target-moderator coupling scheme, the ortho-para-hydrogen ratio, po...

  17. Neutronics of pulsed spallation neutron sources

    International Nuclear Information System (INIS)

    Watanabe, Noboru

    2003-01-01

    Various topics and issues on the neutronics of pulsed spallation neutron sources, mainly for neutron scattering experiments, are reviewed to give a wide circle of readers a better understanding of these sources in order to achieve a high neutronic performance. Starting from what neutrons are needed, what the spallation reaction is and how to produce slow-neutrons more efficiently, the outline of the target and moderator neutronics are explained. Various efforts with some new concepts or ideas have already been devoted to obtaining the highest possible slow-neutron intensity with desired pulse characteristics. This paper also reviews the recent progress of such efforts, mainly focused on moderator neutronics, since moderators are the final devices of a neutron source, which determine the source performance. Various governing parameters for neutron-pulse characteristics such as material issues, geometrical parameters (shape and dimensions), the target-moderator coupling scheme, the ortho-para-hydrogen ratio, poisoning, etc are discussed, aiming at a high performance pulsed spallation source

  18. RHEED studies of MBE growth mechanisms of CdTe and CdMnTe

    Energy Technology Data Exchange (ETDEWEB)

    Waag, A.; Behr, T.; Litz, T.; Kuhn-Heinrich, B.; Hommel, D.; Landwehr, G. (Physikalisches Inst., Univ. Wuerzburg (Germany))

    1993-01-30

    We report on reflection high energy electron diffraction (RHEED) studies of molecular beam epitaxy (MBE) growth of CdTe and CdMnTe on (100) oriented CdTe substrates. RHEED oscillations were measured for both the growth and desorption of CdTe and CdMnTe as a function of flux and temperature. For the first time, the influence of laser and electron irradiation on the growth rate, as well as desorption, of CdTe is studied in detail using RHEED oscillations. We found a very small effect on the growth rate as well as on the CdTe desorption rate. The growth rate of CdTe was determined for different temperatures and CdTe flux ratios. The obtained experimental results are compared with a kinetic growth model to get information on the underlying growth processes, taking into account the influence of a precursor by including surface diffusion. From the comparison between model and experimental results the sticking coefficients of Cd and Te are determined. The growth rate of CdMnTe increases with Mn flux. This dependence can be used to calibrate the Mn content during growth by comparing the growth rate of CdTe with the growth rate of CdMnTe. The change in growth rate has been correlated with Mn content via photoluminescence measurements. In addition, the sticking coefficient of Mn is derived by comparing experimental results with a kinetic growth model. For high manganese content a transition to three-dimensional growth occurs. (orig.).

  19. ASTRO-H CdTe detectors proton irradiation at PIF

    International Nuclear Information System (INIS)

    Limousin, O.; Renaud, D.; Horeau, B.; Dubos, S.; Laurent, P.; Lebrun, F.; Chipaux, R.; Boatella Polo, C.; Marcinkowski, R.; Kawaharada, M.; Watanabe, S.; Ohta, M.; Sato, G.; Takahashi, T.

    2015-01-01

    Asbstract: The French Atomic Energy Commission (CEA), with the support of the European Space Agency (ESA), is partner of the Soft Gamma-Ray Detector (SGD) and the Hard X-ray Imager (HXI) onboard the 6th Japanese X-ray scientific satellite ASTRO-H (JAXA) initiated by the Institute of Space and Astronautical Science (ISAS). Both scientific instruments, one hosting a series of Compton Gamma Cameras and the other being a focal plane of a grazing incidence mirror telescope in the hard X-ray domain, are equipped with Cadmium Telluride based detectors. ASTRO-H will be operated in a Low Earth Orbit with a 31° inclination at ~550 km altitude, thus passing daily through the South Atlantic Anomaly radiation belt, a specially harsh environment where the detectors are suffering the effect of the interaction with trapped high energy protons. As CdTe detector performance might be affected by the irradiation, we investigate the effect of the accumulated proton fluence on their spectral response. To do so, we have characterized and irradiated representative samples of SGD and HXI detector under different conditions. The detectors in question, from ACRORAD, are single-pixels having a size of 2 mm by 2 mm and 750 µm thick. The Schottky contact is either made of an Indium or Aluminum for SGD and HXI respectively. We ran the irradiation test campaign at the Proton Irradiation Facility (PIF) at PSI, and ESA approved equipment to evaluate the radiation hardness of flight hardware. We simulated the proton flux expected on the sensors over the entire mission, and secondary neutrons flux due to primary proton interactions into the surrounding BGO active shielding. We eventually characterized the detector response evolution, emphasizing each detector spectral response as well as its stability by studying the so-called Polarization effect. The latter is provoking a spectral response degradation against time as a charge accumulation process occurs in Schottky type CdTe sensors. In this paper

  20. Precipitation of Ag2Te in the thermoelectric material AgSbTe2

    International Nuclear Information System (INIS)

    Sugar, Joshua D.; Medlin, Douglas L.

    2009-01-01

    The microstructure of AgSbTe 2 , prepared by solidification, is investigated using electron microscopy. During solidification and thermal treatment, the material separates into a two-phase mixture of a rocksalt phase, which is Ag 22 Sb 28 Te 50 , and silver telluride, Ag 2 Te. Ag 2 Te formation results either from eutectic solidification (large lamellar structures), or by solid-state precipitation (fine-scale particles). The crystal structure of the AgSbTe 2 phase determined by electron diffraction is consistent with a rocksalt structure that has a disordered cation sublattice. A preferred crystallographic orientation relationship at the interface between the matrix and the low-temperature monoclinic Ag 2 Te phase is defined and discussed. This orientation relationship is observed for both second-phase morphologies. In both cases, the orientation relationship originates from a topotactic (cube-on-cube) alignment of the Te sublattices in the initially cubic Ag 2 Te and the matrix at elevated temperature. This Te sublattice alignment is retained as the Ag 2 Te undergoes a cubic-to-monoclinic transformation during cooling. This orientation relationship is observed for both second-phase morphologies.

  1. Analysis of CdS/CdTe devices incorporating a ZnTe:Cu/Ti Contact

    International Nuclear Information System (INIS)

    Gessert, T.A.; Asher, S.; Johnston, S.; Young, M.; Dippo, P.; Corwine, C.

    2007-01-01

    High-performance CdS/CdTe photovoltaic devices can be produced using a ZnTe:Cu/Ti back contact deposited onto the CdTe layer. We observe that prolonged exposure of the ZnTe:Cu and Ti sputtering targets to an oxygen-containing plasma significantly reduces device open-circuit voltage and fill factor. High-resolution compositional analysis of these devices reveals that Cu concentration in the CdTe and CdS layers is lower for devices with poor performance. Capacitance-voltage analysis and related numerical simulations indicate that the net acceptor concentration in the CdTe is also lower for devices with poor performance. Photoluminescence analyses of the junction region reveal that the intensity of a luminescent peak associated with a defect complex involving interstitial Cu (Cu i ) and oxygen on Te (O Te ) is reduced in devices with poor performance. Combined with thermodynamic considerations, these results suggest that oxygen incorporation into the ZnTe:Cu sputtering target reduces the ability of sputtered ZnTe:Cu film to diffuse Cu into the CdTe

  2. Liquidus surface of the triple reciprocal system PbTe+CdS↔PbS+CdTe

    International Nuclear Information System (INIS)

    Tomashik, Z.F.; Tomashik, V.N.

    1987-01-01

    Using differential-thermal and microstructural analyses and mathematical design interaction in PbTe-CdS system is studied. Liquidus surface of the triple reciprocal system PbTe+CdS↔PbS+CdTe is plotted. It is shown that PbTe-CdS system phase diagram is of eutectic type. Maximal solubility of CdS in PbTe attains 13 mol%, and of PbTe in CdS is not over 1 mol%. Projection of liquidus surface of the PbTe+CdS↔PbS+CdTe triple reciprocal system consists of two primary crystallization fields: CdTe x S 1-x and PbTe x S 1-x solid solutions separated by eutectic line

  3. Phase diagram of SnTe-CdSe cross-section of SnTe+CdSe reversible SnSe+CdTe ternary reciprocal system

    International Nuclear Information System (INIS)

    Dubrovin, I.V.; Budennaya, L.D.; Mizetskaya, I.B.; Sharkina, Eh.V.

    1986-01-01

    Phase equilibrium diagram of SnTe-CdSe cross-section of Sn, Cd long Te, Se ternary reciprocal system is investigated using the methods of differential thermal, X-ray phase, and microstructural analyses. Maximum length of solid solutions on the base of SnTe corresponds to approximately 14 mol.% at 1050 K and approximately 3 mol.% of CdSe at 670 K. Region of solid solutions on the base of CdSe corresponds to less than 1 mol.% of SnTe at room temperature. SnTe-CdSe cross-section is not a quasibinar one. Equilibrium is shifted to the left in the SnTe+CdSe reversible SnSe+CdTe reciprocal system

  4. The hydrogen anomaly problem in neutron Compton scattering

    Science.gov (United States)

    Karlsson, Erik B.

    2018-03-01

    Neutron Compton scattering (also called ‘deep inelastic scattering of neutrons’, DINS) is a method used to study momentum distributions of light atoms in solids and liquids. It has been employed extensively since the start-up of intense pulsed neutron sources about 25 years ago. The information lies primarily in the width and shape of the Compton profile and not in the absolute intensity of the Compton peaks. It was therefore not immediately recognized that the relative intensities of Compton peaks arising from scattering on different isotopes did not always agree with values expected from standard neutron cross-section tables. The discrepancies were particularly large for scattering on protons, a phenomenon that became known as ‘the hydrogen anomaly problem’. The present paper is a review of the discovery, experimental tests to prove or disprove the existence of the hydrogen anomaly and discussions concerning its origin. It covers a twenty-year-long history of experimentation, theoretical treatments and discussions. The problem is of fundamental interest, since it involves quantum phenomena on the subfemtosecond time scale, which are not visible in conventional thermal neutron scattering but are important in Compton scattering where neutrons have two orders of magnitude times higher energy. Different H-containing systems show different cross-section deficiencies and when the scattering processes are followed on the femtosecond time scale the cross-section losses disappear on different characteristic time scales for each H-environment. The last section of this review reproduces results from published papers based on quantum interference in scattering on identical particles (proton or deuteron pairs or clusters), which have given a quantitative theoretical explanation both regarding the H-cross-section reduction and its time dependence. Some new explanations are added and the concluding chapter summarizes the conditions for observing the specific quantum

  5. Aardkastanje, onopvallend en te weinig om te eten

    NARCIS (Netherlands)

    Spruijt, T.

    2010-01-01

    Hij staat vanaf half juni volop in bloei, maar wordt door weinigen gezien. Hoewel een zoektocht op Google anders doet vermoeden, wordt hij niet meer gegeten. De Aardkastanje is daarvoor te onopvallend en te zeldzaam in Nederland. Toch is het een bijzondere schermbloem.

  6. Neutron radiography with ultracold neutrons

    International Nuclear Information System (INIS)

    Bates, J.C.

    1981-01-01

    The neutron transmission factor of very thin films may be low if the neutron energy is comparable to the pseudo-potential of the film material. Surprisingly, perhaps, it is relatively easy to obtain neutrons with such low energies in sufficient numbers to produce neutron radiographs. (orig.)

  7. Optical phonons in PbTe/CdTe multilayer heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Novikova, N. N.; Yakovlev, V. A. [Russian Academy of Sciences, Institute for Spectroscopy (Russian Federation); Kucherenko, I. V., E-mail: kucheren@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Karczewski, G. [Polish Academy of Sciences, Institute of Physics (Poland); Aleshchenko, Yu. A.; Muratov, A. V.; Zavaritskaya, T. N.; Melnik, N. N. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2015-05-15

    The infrared reflection spectra of PbTe/CdTe multilayer nanostructures grown by molecular-beam epitaxy are measured in the frequency range of 20–5000 cm{sup −1} at room temperature. The thicknesses and high-frequency dielectric constants of the PbTe and CdTe layers and the frequencies of the transverse optical (TO) phonons in these structures are determined from dispersion analysis of the spectra. It is found that the samples under study are characterized by two TO phonon frequencies, equal to 28 and 47 cm{sup −1}. The first frequency is close to that of TO phonons in bulk PbTe, and the second is assigned to the optical mode in structurally distorted interface layers. The Raman-scattering spectra upon excitation with the radiation of an Ar{sup +} laser at 514.5 nm are measured at room and liquid-nitrogen temperatures. The weak line at 106 cm{sup −1} observed in these spectra is attributed to longitudinal optical phonons in the interface layers.

  8. Neutron Skins and Neutron Stars

    OpenAIRE

    Piekarewicz, J.

    2013-01-01

    The neutron-skin thickness of heavy nuclei provides a fundamental link to the equation of state of neutron-rich matter, and hence to the properties of neutron stars. The Lead Radius Experiment ("PREX") at Jefferson Laboratory has recently provided the first model-independence evidence on the existence of a neutron-rich skin in 208Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron be...

  9. One directional polarized neutron reflectometry with optimized reference layer method

    International Nuclear Information System (INIS)

    Masoudi, S. Farhad; Jahromi, Saeed S.

    2012-01-01

    In the past decade, several neutron reflectometry methods for determining the modulus and phase of the complex reflection coefficient of an unknown multilayer thin film have been worked out among which the method of variation of surroundings and reference layers are of highest interest. These methods were later modified for measurement of the polarization of the reflected beam instead of the measurement of the intensities. In their new architecture, these methods not only suffered from the necessity of change of experimental setup but also another difficulty was added to their experimental implementations. This deficiency was related to the limitations of the technology of the neutron reflectometers that could only measure the polarization of the reflected neutrons in the same direction as the polarization of the incident beam. As the instruments are limited, the theory has to be optimized so that the experiment could be performed. In a recent work, we developed the method of variation of surroundings for one directional polarization analysis. In this new work, the method of reference layer with polarization analysis has been optimized to determine the phase and modulus of the unknown film with measurement of the polarization of the reflected neutrons in the same direction as the polarization of the incident beam.

  10. Identification of new neutron-rich actinide isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Oura, Yasuji; Sakama, Minoru; Ohyama, T. [Tokyo Metropolitan Univ. (Japan)] [and others

    1999-10-01

    To advance research on new neutron-deficient actinide isotopes using an on-line isotope separator combined with a gas-jet injector installed in the JAERI Tandem accelerator, Tokai, performance test of the equipment was carried out. Efficiency of the product isotopes being transported from the target chamber to the measuring system was greatly improved by employing lead iodides (PbI{sub 2}) as the aerosol carrier. With the help of this technique, the authors succeeded in synthesizing and identifying actinide isotopes, {sup 235}Am and {sup 236}Am, and measured their alpha-decay half-life. (S. Ohno)

  11. Calibration of the GNU and HSREM neutron survey instruments

    International Nuclear Information System (INIS)

    Eakins, J.S.; Hager, L.G.; Leake, J.W.; Mason, R.S.; Tanner, R.J.

    2017-01-01

    Two innovative designs of neutron survey instrument have recently been developed to estimate ambient dose equivalent in the workplace: the GNU has an improved energy-independence of response in the meV to TeV range; the HSREM is a comparatively lightweight device covering the meV to 10 MeV range. Both designs offer good detection sensitivity, allowing measurements to be made efficiently and thereby minimizing the exposure to their users. Prototypes of both devices have been constructed and exposed to sets of well-characterized reference fields: the resulting measured responses are presented and discussed here, compared against comprehensive Monte Carlo data.

  12. Calibration of the GNU and HSREM neutron survey instruments

    Energy Technology Data Exchange (ETDEWEB)

    Eakins, J.S., E-mail: jonathan.eakins@phe.gov.uk [Public Health England, CRCE, Chilton, Didcot, Oxon OX11 0RQ (United Kingdom); Hager, L.G. [Public Health England, CRCE, Chilton, Didcot, Oxon OX11 0RQ (United Kingdom); Leake, J.W.; Mason, R.S. [Sherwood Nutec Scientific Ltd., Kent (United Kingdom); Tanner, R.J. [Public Health England, CRCE, Chilton, Didcot, Oxon OX11 0RQ (United Kingdom)

    2017-04-21

    Two innovative designs of neutron survey instrument have recently been developed to estimate ambient dose equivalent in the workplace: the GNU has an improved energy-independence of response in the meV to TeV range; the HSREM is a comparatively lightweight device covering the meV to 10 MeV range. Both designs offer good detection sensitivity, allowing measurements to be made efficiently and thereby minimizing the exposure to their users. Prototypes of both devices have been constructed and exposed to sets of well-characterized reference fields: the resulting measured responses are presented and discussed here, compared against comprehensive Monte Carlo data.

  13. Pessoas com deficiência: nossa maior minoria People with disability: our larger minority

    Directory of Open Access Journals (Sweden)

    Wederson Rufino dos Santos

    2008-09-01

    Full Text Available Os estudos internacionais sobre deficiência são um campo consolidado nas ciências sociais, embora no Brasil seja incipiente e frágil. O conceito de deficiência diz respeito às restrições sociais impostas às pessoas que possuem variedade nas habilidades corporais. O objetivo deste artigo é analisar o debate sobre deficiência a partir de dois enfoques: 1 compreender a deficiência como uma manifestação da diversidade humana, partindo da análise do debate do modelo social da deficiência - uma corrente política e teórica que reconhece a deficiência como opressão sofrida pelas pessoas com lesões em ambientes sociais pouco adaptados às diversidades corporais; 2 demonstrar que a mudança na compreensão do corpo com deficiência como manifestação da diversidade corporal traz melhores instrumentos para o modo como a sociedade deve se organizar para promover justiça às pessoas com deficiência, promovendo a garantia dos direitos de cidadania dessas pessoas que representam 14,5% da população brasileira, segundo o último Censo de 2000.Although incipient in Brazil, international studies on disability are a consolidated field in social sciences. The concept of disability concerns issues of health or illness faced by people whose abilities are restricted by body impairments. This paper aims to analyze the debate on disability based on two approaches: 1 to understand disability as a manifestation of the human being diversity, analyzing the debate on the social model of disability - a political and theoretical trend that considers deficiency as oppression suffered by impaired people in social environments not adapted to corporal diversities; 2 to show that changes in the comprehension of the disabled body as manifestation of corporal diversity brings better tools to the way society must organize itself to promote justice for disabled people, thus ensuring citizenship rights for those 14.5% of the Brazilian population, according to

  14. Neutron-neutron probe for uranium exploration

    International Nuclear Information System (INIS)

    Smith, R.C.

    1979-01-01

    A neutron activation probe for assaying the amount of fissionable isotopes in an ore body is described which comprises a casing which is movable through a borehole in the ore body, a neutron source and a number of delayed neutron detectors arranged colinearly in the casing below the neutron source for detecting delayed neutrons

  15. Study of the neutron deficient nucleus {sup 180}Pt

    Energy Technology Data Exchange (ETDEWEB)

    Mueller-Gatermann, Claus; Fransen, Christoph; Dewald, Alfred; Braunroth, Thomas; Litzinger, Julia; Jolie, Jan; Zell, Karl-Oskar [Institut fuer Kernphysik, Universitaet zu Koeln (Germany); Julin, Rauno; Grahn, Tuomas [Dept. of Physics, University of Jyvaeskylae (Finland); Petkov, Pavel [Bulgarian Academy of Sciences, Sofia (Bulgaria)

    2016-07-01

    The nuclei {sup 176,178,180}Os are known to show the characteristic features of the critical point symmetry X(5). This symmetry was introduced by F. Iachello and describes nuclei at the critical point of deformation phase transition from a vibrator to axial rotor. A rapid change in deformation is expected when the proton number is changed, because the neutron number is close to mid-shell. Therefore we performed measurements to determine the lifetimes of low lying states in {sup 180}Pt which is a neighbor of the X(5) type Os nuclei, from which absolute transition probabilities can be deduced directly. In this contribution we will report on a Recoil distance Doppler shift experiment which was performed at the JYFL, Jyvaeskylae (Finland). Furthermore the results of the {sup 168}Yb({sup 16}O,4n){sup 180}Pt experiment using the fast timing technique to determine the lifetime of the rather longlived first 2{sup +} state at the IKP, University of Cologne (Germany) are presented. The experimental results will be discussed in the framework of the Interacting Boson Model and compared to a General Collective Model calculation.

  16. Neutron activation determination of impurities in high-purity bismuth with separation of matrix in form of hydroxide

    International Nuclear Information System (INIS)

    Artyukhin, P.I.; Shavinskij, B.M.; Mityakin, Yu.L.

    1979-01-01

    The technique of neutron activation determination of 15 impurity elements (Au, Ag, Ba, Cd, Co, Cs, Cu, Hg, K, Na, Ni, Se, Sr, Te, Zn) in high-purity bismuth (impurity content is approximately 10 -6 -10 -10 %) is presented. Bismuth hydroxide precipitation by ammonia from nitric acid solutions was used to separate bismuth from alkali, alkaline earth metals and elements forming stable ammines. Gold, selenium and tellurium are isolated in the form of metals at reduction by muriatic hydrazine. Results of analyzing two samples of special purity bismuth are presented. Neutron flux comprised 0.8-1x10 13 n/cm 2 xs. Radiation time was equal to 90 hours

  17. High mobility 2D electron gas in CdTe/CdMgTe heterostructures

    International Nuclear Information System (INIS)

    Karczewski, G.; Jaroszynski, J.; Kurowski, M.; Barcz, A.; Wojtowicz, T.; Kossut, J.

    1997-01-01

    We report on iodine doping of molecular beam epitaxy (MBE)-grown Cd(Mn)Te quasi-bulk films and modulation-doped CdTe/Cd 1-y Mg y Te two-dimensional (2D) single quantum well structures. Modulation doping with iodine of CdTe/Cd 1-y Mg y Te structures resulted in fabrication of a 2D electron gas with mobility exceeding 10 5 cm 2 /(Vs). This is the highest mobility reported in wide-gap II-VI materials

  18. Cumulative effects of Te precipitates in CdZnTe radiation detectors

    International Nuclear Information System (INIS)

    Bolotnikov, A.E.; Camarda, G.S.; Carini, G.A.; Cui, Y.; Li, L.; James, R.B.

    2007-01-01

    High-quality radiation detector-grade CdZnTe material is free from large-scale defects, such as grain boundaries, twins, and large Te or Cd inclusions (>50 μm), although it usually contains high concentrations of uniformly distributed Te inclusions and precipitates, typically of ∼20-μm-diameter size or smaller. We address the effects of the small-size Te precipitates on charge collection in CZT detectors, the significance of which is not yet well characterized. The strong correlation that we earlier found between the high-resolution X-ray maps and IR images proved that even small Te precipitates can trap substantial fractions of charge from the electron cloud. In this work, we modeled the transport of an electron cloud across idealized CZT devices containing Te precipitates to demonstrate that their cumulative effect can explain the degradation of energy resolution and the detection efficiency losses observed in actual CZT devices. Due to lack of experimental data on how the Te precipitates interact with an electron cloud, we developed a simplified (phenomenological) model based on the geometrical aspects of the problem. Despite its simplicity, the model correctly reproduced many experimental facts and gave quantitative predictions on the extent to which the presence of Te precipitates and inclusions can be tolerated. The broadening of the electron cloud due to repulsion and diffusion is at the core of the problem, making even low concentrations of small precipitates important in the device's performance

  19. Iodine Deficiency

    Science.gov (United States)

    ... Fax/Phone Home » Iodine Deficiency Leer en Español Iodine Deficiency Iodine is an element that is needed ... world’s population remains at risk for iodine deficiency. Iodine Deficiency FAQs WHAT IS THE THYROID GLAND? The ...

  20. Neutron radiative capture reactions on nuclei of relevance to 0νββ, dark matter and neutrino/antineutrino searches

    Science.gov (United States)

    Tornow, W.; Bhike, Megha

    2015-05-01

    A program is underway at the Triangle Universities Nuclear Laboratory (TUNL) to measure the neutron capture cross section in the 0.5 to 15 MeV energy range on nuclei whose radioactive daughters could potentially create backgrounds in searches for rare events. Here, we refer to neutrino-less double-beta decay and dark-matter searches, and to detectors built for neutrino and/or antineutrino studies. Neutron capture cross-section data obtained by using the activation method are reported for 40Ar, 74,76Ge, 128,130Te and 136Xe and compared to model calculations and evaluations.

  1. Neutron radiative capture reactions on nuclei of relevance to 0νββ, dark matter and neutrino/antineutrino searches

    Directory of Open Access Journals (Sweden)

    Tornow W.

    2015-01-01

    Full Text Available A program is underway at the Triangle Universities Nuclear Laboratory (TUNL to measure the neutron capture cross section in the 0.5 to 15 MeV energy range on nuclei whose radioactive daughters could potentially create backgrounds in searches for rare events. Here, we refer to neutrino-less double-beta decay and dark-matter searches, and to detectors built for neutrino and/or antineutrino studies. Neutron capture cross-section data obtained by using the activation method are reported for 40Ar, 74,76Ge, 128,130Te and 136Xe and compared to model calculations and evaluations.

  2. Quantitative neutron radiography using neutron absorbing honeycomb

    International Nuclear Information System (INIS)

    Tamaki, Masayoshi; Oda, Masahiro; Takahashi, Kenji; Ohkubo, Kohei; Tasaka, Kanji; Tsuruno, Akira; Matsubayashi, Masahito.

    1993-01-01

    This investigation concerns quantitative neutron radiography and computed tomography by using a neutron absorbing honeycomb collimator. By setting the neutron absorbing honeycomb collimator between object and imaging system, neutrons scattered in the object were absorbed by the honeycomb material and eliminated before coming to the imaging system, but the neutrons which were transmitted the object without interaction could reach the imaging system. The image by purely transmitted neutrons gives the quantitative information. Two honeycombs were prepared with coating of boron nitride and gadolinium oxide and evaluated for the quantitative application. The relation between the neutron total cross section and the attenuation coefficient confirmed that they were in a fairly good agreement. Application to quantitative computed tomography was also successfully conducted. The new neutron radiography method using the neutron-absorbing honeycomb collimator for the elimination of the scattered neutrons improved remarkably the quantitativeness of the neutron radiography and computed tomography. (author)

  3. Measure of the slowing down area of thermal state 1,45 eV neutrons in the graphite; Mesure de l'aire de ralentissement des neutrons dans le graphite de 1,45 eV a l'etat thermique

    Energy Technology Data Exchange (ETDEWEB)

    Robert, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1956-12-15

    The life of a neutron emitted as a fast one within a moderating medium may be divided into two parts; at first it is slowed down colliding with the nuclei of the medium; later on, as soon as its energy is of the order of the thermal agitation energy, it diffuses until captured by some nucleus. As a matter of fact, dividing the evolution of a neutron into two phases, a slowing down phase and a diffusing phase is arbitrary, since the thermal equilibrium is attained stepwise. This report is intended to examine the means of inferring the distribution of thermal neutrons from the distribution of fast neutrons on the basis of the distribution of nascent thermal neutrons and of the law of scattering. (author) [French] La vie d'un neutron emis a l'etat rapide dans un milieu moderateur comprend 2 parties: au debut il se ralentit par chocs sur les noyaux du milieu; ensuite, lorsque son energie est de l'ordre de l'energie d'agitation thermique, il diffuse jusqu'a sa capture par un noyau. La separation de l'evolution d'un neutron en deux phases, phase de ralentissement, puis phase de diffusion, est, en realite, arbitraire; un neutron doit atteindre l'equilibre thermique progressivement. L'objet de ce rapport est de voir comment on peut deduire la repartition des thermiques de la repartition des rapides connaissant la repartition des thermiques naissants et la loi de diffusion. (au0010te.

  4. Electronic structures and stability of Ni/Bi2Te3 and Co/Bi2Te3 interfaces

    International Nuclear Information System (INIS)

    Xiong Ka; Wang Weichao; Alshareef, Husam N; Gupta, Rahul P; Gnade, Bruce E; Cho, Kyeongjae; White, John B

    2010-01-01

    We investigate the electronic structures and stability for Ni/Bi 2 Te 3 , NiTe/Bi 2 Te 3 , Co/Bi 2 Te 3 and CoTe 2 /Bi 2 Te 3 interfaces by first-principles calculations. It is found that the surface termination strongly affects the band alignment. Ni and Co are found to form Ohmic contacts to Bi 2 Te 3 . The interface formation energy for Co/Bi 2 Te 3 interfaces is much lower than that of Ni/Bi 2 Te 3 interfaces. Furthermore, we found that NiTe on Bi 2 Te 3 is more stable than Ni, while the formation energies for Co and CoTe 2 on Bi 2 Te 3 are comparable.

  5. Ga-Bi-Te system

    International Nuclear Information System (INIS)

    Rustamov, P.G.; Seidova, N.A.; Shakhbazov, M.G.; AN Azerbajdzhanskoj SSR, Baku. Inst. Neorganicheskoj i Fizicheskoj Khimii)

    1976-01-01

    To elucidate the nature of interaction in the system Ga-Bi-Te, a study has been made of sections GaTe-Bi 2 Te 3 , Ga 2 Te 3 -Bi, GaTe-Bi and Bi 2 Te 3 -Ga. The alloys have been prepared by direct melting of the components or their alloys with subsequent homogenizin.o annealing at 400 deg C. The study has been made by the methods of differential thermal, microstructural analysis and by microhardness measurements. On the basis of literature data and data obtained a projection of the liquidus surface of the phase diagram for the system Ga-Bi-Te has been constructed. In the ternary system there are 17 curves of monovariant equilibrium dividing the liquidus into 10 fields of primary crystallization of phases, 9 points of non-variant equilibrium of which 4 points are triple eutectics and 5 points are triple peritectics

  6. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1993-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  7. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1994-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  8. Neutron detection efficiency determinations for the TUNL neutron-neutron and neutron-proton scattering-length measurements

    International Nuclear Information System (INIS)

    Trotter, D.E. Gonzalez; Meneses, F. Salinas; Tornow, W.; Crowell, A.S.; Howell, C.R.; Schmidt, D.; Walter, R.L.

    2009-01-01

    The methods employed and the results obtained from measurements and calculations of the detection efficiency for the neutron detectors used at Triangle Universities Nuclear Laboratory (TUNL) in the simultaneous determination of the 1 S 0 neutron-neutron and neutron-proton scattering lengths a nn and a np , respectively, are described. Typical values for the detector efficiency were 0.3. Very good agreement between the different experimental methods and between data and calculation has been obtained in the neutron energy range below E n =13MeV.

  9. Status of neutron beam utilization at the Dalat nuclear research reactor

    International Nuclear Information System (INIS)

    Dien, Nguyen Nhi; Hai, Nguyen Canh

    2003-01-01

    The 500-kW Dalat nuclear research reactor was reconstructed from the USA-made 250-kW TRIGA Mark II reactor. After completion of renovation and upgrading, the reactor has been operating at its nominal power since 1984. The reactor is used mainly for radioisotope production, neutron activation analysis, neutron beam researches and reactor physics study. In the framework of the reconstruction and renovation project of the 1982-1984 period, the reactor core, the control and instrumentation system, the primary and secondary cooling systems, as well as other associated systems were newly designed and installed by the former Soviet Union. Some structures of the reactor, such as the reactor aluminum tank, the graphite reflector, the thermal column, horizontal beam tubes and the radiation concrete shielding have been remained from the previous TRIGA reactor. As a typical configuration of the TRIGA reactor, there are four neutron beam ports, including three radial and one tangential. Besides, there is a large thermal column. Until now only two-neutron beam ports and the thermal column have been utilized. Effective utilization of horizontal experimental channels is one of the important research objectives at the Dalat reactor. The research program on effective utilization of these experimental channels was conducted from 1984. For this purpose, investigations on physical characteristics of the reactor, neutron spectra and fluxes at these channels, safety conditions in their exploitation, etc. have been carried out. The neutron beams, however, have been used only since 1988. The filtered thermal neutron beams at the tangential channel have been extracted using a single crystal silicon filter and mainly used for prompt gamma neutron activation analysis (PGNAA), neutron radiography (NR) and transmission experiments (TE). The filtered quasi-monoenergetic keV neutron beams using neutron filters at the piercing channel have been used for nuclear data measurements, study on

  10. Electronic structures and stability of Ni/Bi2Te3 and Co/Bi2Te3 interfaces

    KAUST Repository

    Xiong, Ka; Wang, Weichao; Alshareef, Husam N.; Gupta, Rahul P.; White, John B.; Gnade, Bruce E.; Cho, Kyeongjae

    2010-01-01

    We investigate the electronic structures and stability for Ni/Bi 2Te3, NiTe/Bi2Te3, Co/Bi 2Te3 and CoTe2/Bi2Te3 interfaces by first-principles calculations. It is found that the surface termination strongly affects the band alignment. Ni and Co are found to form Ohmic contacts to Bi2Te3. The interface formation energy for Co/Bi2Te3 interfaces is much lower than that of Ni/Bi2Te3 interfaces. Furthermore, we found that NiTe on Bi2Te3 is more stable than Ni, while the formation energies for Co and CoTe2 on Bi2Te3 are comparable. © 2010 IOP Publishing Ltd.

  11. Electronic structures and stability of Ni/Bi2Te3 and Co/Bi2Te3 interfaces

    KAUST Repository

    Xiong, Ka

    2010-03-04

    We investigate the electronic structures and stability for Ni/Bi 2Te3, NiTe/Bi2Te3, Co/Bi 2Te3 and CoTe2/Bi2Te3 interfaces by first-principles calculations. It is found that the surface termination strongly affects the band alignment. Ni and Co are found to form Ohmic contacts to Bi2Te3. The interface formation energy for Co/Bi2Te3 interfaces is much lower than that of Ni/Bi2Te3 interfaces. Furthermore, we found that NiTe on Bi2Te3 is more stable than Ni, while the formation energies for Co and CoTe2 on Bi2Te3 are comparable. © 2010 IOP Publishing Ltd.

  12. Modelos teóricos da deficiência no discurso acadêmico brasileiro: perspectivas integracionistas e o campo da saúde coletiva

    OpenAIRE

    Bárbara Fonseca da Costa Caldeira de Andrada

    2013-01-01

    Atualmente, a deficiência é pensada através de dois modelos principais: o modelo médico e o modelo social. Cada um deles adota paradigmas próprios para a definição da deficiência e a proposição de ações reparadoras. Os efeitos sociais da adoção destes modelos variam amplamente, indo da exclusão à inclusão social de pessoas com deficiência. Esta dissertação apresenta a contribuição de perspectivas críticas recentes - nomeadas aqui como perspectivas integracionistas - que congregam elementos do...

  13. Neutron detection efficiency determinations for the TUNL neutron-neutron and neutron-proton scattering-length measurements

    Energy Technology Data Exchange (ETDEWEB)

    Trotter, D.E. Gonzalez [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)], E-mail: crowell@tunl.duke.edu; Meneses, F. Salinas [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Tornow, W. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)], E-mail: tornow@tunl.duke.edu; Crowell, A.S.; Howell, C.R. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Schmidt, D. [Physikalisch-Technische Bundesanstalt, D-38116, Braunschweig (Germany); Walter, R.L. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)

    2009-02-11

    The methods employed and the results obtained from measurements and calculations of the detection efficiency for the neutron detectors used at Triangle Universities Nuclear Laboratory (TUNL) in the simultaneous determination of the {sup 1}S{sub 0} neutron-neutron and neutron-proton scattering lengths a{sub nn} and a{sub np}, respectively, are described. Typical values for the detector efficiency were 0.3. Very good agreement between the different experimental methods and between data and calculation has been obtained in the neutron energy range below E{sub n}=13MeV.

  14. Electrical properties of gallium arsenide irradiated with electrons and neutrons

    International Nuclear Information System (INIS)

    Kol'chenko, T.I.; Lomako, V.M.

    1975-01-01

    A study was made of changes in the electrical properties of GaAs doped with Te, S, Se, Si, Ge, Sn (n 0 approximately 10 16 -10 18 cm -3 ) and irradiated either with 2.5-28 MeV electrons or with fast reactor neutrons. An analysis of changes in the electron density indicated that the rate of carrier removal by electron bombardment was independent of the dopant but was governed by isolated radiation defects. The change in the mobility due to irradiation with 2.5-10 MeV electrons was also governed by isolated defects. When the electron energy was increased to 28 MeV the main contribution to the change in the mobility was made by defect clusters. In the neutron-irradiation case the changes in the carrier density and mobility were mainly due to defect clusters and the nature of changes in the electrical properties was again independent of the dopant

  15. Use of the helium-3 proportional counter for neutron spectrometry; Utilisation du compteur proportionnel a helium 3 pour la spectrometrie des neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Vialettes, H; Le Thanh, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-07-01

    compteur proportionnel a helijum 3 a e,te envisagee. Ce rapport presente les principes d'utilisation du spectrometre a helium 3, et les methodes de calcul qui permettent de tenir compte des deux effets principaux qui tendent a deformer le spectre obtenus: - l'absorption d'energie par les parois du compteur - la perte d'energie des neutrons incidents par chocs elastiques sur les noyaux d'helium 3. A titre d'application on a trace le spectre des neutrons emis par une source de polonium-lithium; les resultats obtenus sont en excellent accord avec les predictions theoriques. (auteurs)

  16. Analysis of MCNP simulated gamma spectra of CdTe detectors for boron neutron capture therapy.

    Science.gov (United States)

    Winkler, Alexander; Koivunoro, Hanna; Savolainen, Sauli

    2017-06-01

    The next step in the boron neutron capture therapy (BNCT) is the real time imaging of the boron concentration in healthy and tumor tissue. Monte Carlo simulations are employed to predict the detector response required to realize single-photon emission computed tomography in BNCT, but have failed to correctly resemble measured data for cadmium telluride detectors. In this study we have tested the gamma production cross-section data tables of commonly used libraries in the Monte Carlo code MCNP in comparison to measurements. The cross section data table TENDL-2008-ACE is reproducing measured data best, whilst the commonly used ENDL92 and other studied libraries do not include correct tables for the gamma production from the cadmium neutron capture reaction that is occurring inside the detector. Furthermore, we have discussed the size of the annihilation peaks of spectra obtained by cadmium telluride and germanium detectors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Neutron activation analysis of zinc in forages used in intensive dairy cattle production systems

    International Nuclear Information System (INIS)

    Armelin, M.J.A.; Piasentin, R.M.; Primavesi, O.

    2002-01-01

    Instrumental neutron activation analysis (INAA) was applied for the determination of Zn concentration in the main tropical grass forages used in intensive dairy cattle production systems, in Brazil. Smaller Zn concentration could be verified in the rainy period. Comparison of results obtained in these analyses of forages dry matter with daily requirements pointed towards deficiency of Zn in the forages. (author)

  18. Piezoelectric effect in CdTe/CdMnTe and CdTe/CdZnTe quantum wells

    International Nuclear Information System (INIS)

    Andre, Regis

    1994-01-01

    Materials with zinc-blende type structure are piezoelectric: any strain along a polar axis generates an electrical polarisation. Strained quantum wells of cubic II-VI or III-V semiconductors, grown along [111] or [112] axis, exhibit a strong built-in piezo-electric field (100 kV/cm for 1% strains). Such structures are very promising for applications to optical modulation, but it is necessary to study first the physical properties of piezoelectric heterostructures before they can be used in optical devices. For this purpose, we have performed an optical study of strained CdTe/CdMnTe or CdTe/CdZnTe quantum wells coherently grown by molecular beam epitaxy on [111] or [112] oriented substrates. Effects of piezoelectric field on optical and electronic properties of quantum wells have been analyzed in terms of the envelop function model, taking into account the effects of biaxial strains for [hhk] growth axis. Moreover, we have proposed an original way of measuring piezoelectric field in strained quantum wells, and we have used this method to show that CdTe exhibits strong non-linearities for piezoelectric field versus strain. This effect has never been mentioned before. We have also performed measurements of the piezoelectric coefficient e14 under high hydrostatic pressure inducing strains up to 2%, which shows that part of the non-linear effect is a volume effect. We have also studied the effects of the piezoelectric field on excitons in quantum wells. The binding energy decreases slightly when the electric field increases, but the oscillator strength, for the fundamental transition, decreases dramatically with the overlap of the envelope wavefunctions of electrons and holes. We have performed a modelization of an exciton in a piezoelectric quantum well using two variational parameters. This model provides an accurate calculation of excitonic absorption. Our experimental and theoretical results are in very good agreement, without any fitting parameters, for a large

  19. Dual-Particle Imaging System with Neutron Spectroscopy for Safeguard Applications

    Energy Technology Data Exchange (ETDEWEB)

    Hamel, Michael C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Weber, Thomas M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-11-01

    A dual-particle imager (DPI) has been designed that is capable of detecting gamma-ray and neutron signatures from shielded SNM. The system combines liquid organic and NaI(Tl) scintillators to form a combined Compton and neutron scatter camera. Effective image reconstruction of detected particles is a crucial component for maximizing the performance of the system; however, a key deficiency exists in the widely used iterative list-mode maximum-likelihood estimation-maximization (MLEM) image reconstruction technique. For MLEM a stopping condition is required to achieve a good quality solution but these conditions fail to achieve maximum image quality. Stochastic origin ensembles (SOE) imaging is a good candidate to address this problem as it uses Markov chain Monte Carlo to reach a stochastic steady-state solution. The application of SOE to the DPI is presented in this work.

  20. Growth and optical properties of CdTe quantum dots in ZnTe nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Wojnar, Piotr; Janik, Elzbieta; Baczewski, Lech T.; Kret, Slawomir; Karczewski, G.; Wojtowicz, Tomasz [Institute of Physics, Polish Academy of Sciences, Al Lotnikow 32/46, 02-668 Warsaw (Poland); Goryca, Mateusz; Kazimierczuk, Tomasz; Kossacki, Piotr [Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul Hoza 69, 00-681 Warsaw (Poland)

    2011-09-12

    We report on the formation of optically active CdTe quantum dots in ZnTe nanowires. The CdTe/ZnTe nanostructures have been grown by a gold nanocatalyst assisted molecular beam epitaxy in a vapor-liquid solid growth process. The presence of CdTe insertions in ZnTe nanowire results in the appearance of a strong photoluminescence band in the 2.0 eV-2.25 eV energy range. Spatially resolved photoluminescence measurements reveal that this broad emission consists of several sharp lines with the spectral width of about 2 meV. The large degree of linear polarization of these individual emission lines confirms their nanowire origin, whereas the zero-dimensional confinement is proved by photon correlation spectroscopy.

  1. Electrical and optical properties of SnEuTe and SnSrTe films

    Science.gov (United States)

    Ishida, Akihiro; Tsuchiya, Takuro; Yamada, Tomohiro; Cao, Daoshe; Takaoka, Sadao; Rahim, Mohamed; Felder, Ferdinand; Zogg, Hans

    2010-06-01

    The SnTe, Sn1-xEuxTe and Sn1-xSrxTe (x<0.06) films were prepared by hot wall epitaxy. The ternary alloy films prepared in cation rich condition had hole concentration around 1×1019 cm-3 with high mobility exceeding 2000 cm2/V s at room temperature. Optical transmission spectra were also measured in the temperature range from 100 to 400 K and compared with theoretical calculations. Optical transmission spectra of the SnTe were simulated successfully assuming bumped band edge structures. A band inversion model was proposed for the Sn1-xEuxTe and Sn1-xSrxTe systems, and the optical transmission spectra were also simulated successfully assuming the band inversion model.

  2. Properties of Hg1-xCdxTe epitaxial films grown on (211)CdTe and (211)CdZnTe

    International Nuclear Information System (INIS)

    Di Stefano, M.C.; Gilabert, U.; Heredia, E.; Trigubo, A.B.

    2004-01-01

    Hg 1-x Cd x Te (MCT) epitaxial films have been grown employing single crystalline substrates of CdTe and Cd 0.96 Zn 0.04 Te with (211)Cd and (211)Te crystalline orientations. The Isothermal Vapor Phase Epitaxy (ISOVPE) technique without Hg overpressure has been used for the epitaxial growth. Substrates and films were characterized by optical microscopy, chemical etching and X ray diffraction (Laue technique). The electrical properties were determined by Hall effect measurements. The characterization results allowed to evaluate the crystalline quality of MCT films. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Research Home / < Back To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español Iron-deficiency ... iron-deficiency anemia. Blood tests to screen for iron-deficiency anemia To screen for iron-deficiency anemia, your doctor ...

  4. Neutron stars

    International Nuclear Information System (INIS)

    Irvine, J.M.

    1978-01-01

    The subject is covered in chapters entitled: introduction (resume of stellar evolution, gross characteristics of neutron stars); pulsars (pulsar characteristics, pulsars as neutron stars); neutron star temperatures (neutron star cooling, superfluidity and superconductivity in neutron stars); the exterior of neutron stars (the magnetosphere, the neutron star 'atmosphere', pulses); neutron star structure; neutron star equations of state. (U.K.)

  5. A description of odd mass Xe and Te isotopes in the Interacting Boson–Fermion Model

    Energy Technology Data Exchange (ETDEWEB)

    Abu-Musleh, S. [National Center of Research, Gaza, Palestine (Country Unknown); Phys. Dep., Faculty of Women for Art, Science and Education, Ain Shams University, Cairo (Egypt); Abu-Zeid, H.M. [Phys. Dep., Faculty of Women for Art, Science and Education, Ain Shams University, Cairo (Egypt); Scholten, O. [Kernfysisch Versneller Instituut, University of Groningen, 9747 AA, Groningen (Netherlands)

    2014-07-15

    Recent interest in spectroscopic factors for single-neutron transfer in low-spin states of the even–odd Xenon {sup 125,127,129.131}Xe and even–odd Tellurium, {sup 123,125,127,129,131}Te isotopes stimulated us to study these isotopes within the framework of the Interacting Boson–Fermion Model. The fermion that is coupled to the system of bosons is taken to be in the positive parity 3s{sub 1/2}, 2d{sub 3/2}, 2d{sub 5/2}, 1g{sub 7/2} and in the negative 1h{sub 11/2} single-particle orbits, the complete 50–82 major shell. The calculated energies of low-spin energy levels of the odd isotopes are found to agree well with the experimental data. Also, B(E2), B(M1) values and spectroscopic factors for single-neutron transfer are calculated and compared with experimental data.

  6. Laser Spectroscopy of Neutron Rich Bismuth Isotopes

    CERN Multimedia

    2002-01-01

    %IS344 :\\\\ \\\\ The aim of the experiment is to measure the optical isotope shifts and hyperfine structures of bismuth isotopes across the N=126 shell closure in order to extract the change in mean square charge radii ($\\delta\\langle r^{2}\\rangle$) and static moments. These include the first isotones of lead to be measured directly above the shell closure and will provide new information on the systematics of the kink ($\\delta\\langle r^{2}\\rangle)$ seen in the lead isotopic chain. After two very successful runs the programme has been extended to include the neutron deficient isotopes below $^{201}$Bi to study the systematics across the $i_{13/2}$ neutron sub-shell closure at N=118.\\\\ \\\\ During the initial 2 runs (9 shifts) the isotope shifts and hyperfine structures of three new isotopes, $ ^{210,212,213}$Bi and the 9$^{-}$ isomer of $^{210}$Bi have been measured. The accuracy of the previous measurements of $^{205,206,208}$Bi have been greatly improved. The samples of $ ^{208,210,210^{m}}$Bi were prepared by c...

  7. Performance and Metastability of CdTe Solar Cells with a Te Back-Contact Buffer Layer

    Science.gov (United States)

    Moore, Andrew

    Thin-film CdTe photovoltaics are quickly maturing into a viable clean-energy solution through demonstration of competitive costs and performance stability with existing energy sources. Over the last half decade, CdTe solar technology has achieved major gains in performance; however, there are still aspects that can be improved to progress toward their theoretical maximum efficiency. Perhaps equally valuable as high photovoltaic efficiency and a low levelized cost of energy, is device reliability. Understanding the root causes for changes in performance is essential for accomplishing long-term stability. One area for potential performance enhancement is the back contact of the CdTe device. This research incorporated a thin-film Te-buffer layer into the contact structure, between the CdTe and contact metal. The device performance and characteristics of many different back contact configurations were rigorously studied. CdTe solar cells fabricated with the Te-buffer contact showed short-circuit current densities and open-circuit voltages that were on par with the traditional back-contacts used at CSU. However, the Te-buffer contact typically produced 2% larger fill-factors on average, leading to greater conversation efficiency. Furthermore, using the Te buffer allowed for incorporation of 50% less Cu, which is used for p-type doping but is also known to decrease lifetime and stability. This resulted in an additional 3% fill-factor gain with no change in other parameters compared to the standard-Cu treated device. In order to better understand the physical mechanisms of the Te-buffer contact, electrical and material properties of the Te layer were extracted and used to construct a simple energy band diagram. The Te layer was found to be highly p-type (>1018 cm-3) and possess a positive valence-band offset of 0.35-0.40 eV with CdTe. An existing simulation model incorporating the Te-layer properties was implemented and validated by comparing simulated results of CdTe

  8. On the mean square displacements (MSD) of Hg and Te in HgTe

    International Nuclear Information System (INIS)

    Madhavan, Y.; Ramachandran, K.

    1989-01-01

    The mean square displacements (MSD) of Hg and Te in the perfect system of HgTe are worked out in the modified rigid ion model of Plumelle and Vandevyver. Also the MSD of Hg and Te neighbours around anion and cation vacancies in HgTe are worked out giving an active role for the vacancy following the theory of Maradudin et al. The results are compared with experimental values. (author)

  9. Iron-Deficiency Anemia

    Science.gov (United States)

    ... To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español Iron-deficiency ... anemia. Blood tests to screen for iron-deficiency anemia To screen for iron-deficiency anemia, your doctor ...

  10. M rate at TE. Monitoring at TeV energies

    Energy Technology Data Exchange (ETDEWEB)

    Dorner, Daniela [Universitaet Wuerzburg (Germany); Bretz, Thomas [RWTH Aachen (Germany); Gonzalez, Magdalena; Alfaro, Ruben [Universidad Nacional Autonoma de Mexico (Mexico); Tovmassian, Gagik [Instituto de Astronomia Sede Ensenada (Mexico)

    2016-07-01

    A dedicated long-term monitoring programm at TeV energies has been started by the FACT project about four years ago. Being limited to one site, gaps due to the rotation of the Earth remain in the measured light curves. This makes it difficult to study typical variability time scales of few hours to one day. To allow for systematic studies of continuous observations over up to 12 hours, a second telescope is being installed at a site in about six hours distance in longitude. For the M rate at TE (Monitoring at TeV energies) telescope, a mount from a previous experiment is being refurbished and will be equipped with a new camera. Using silicon based photo sensors like in FACT, an excellent and stable performance will be achieved. M rate at TE is a joint project of German and Mexican universities which aims at extending the blazar monitoring to so far unexplored time ranges. In the presentation, the status of this emerging project is reported.

  11. Solar flare pion and neutron production

    International Nuclear Information System (INIS)

    Forrest, D.J.; Vestrand, W.T.

    1992-01-01

    During cycle 21, the Gamma Ray Spectrometer on SMM observed three large flares with clear evidence for pion decay gamma rays and high energy neutrons. Two of these had an extended emission phase. The emission observed in these extended phases were clearly different from those observed in the impulsive phase. Compared to the impulsive phase, the extended phase emissions were strongly deficient in electron bremsstrahlung relative to the nuclear line emission in the 1.0-7.0 MeV band and appeared to have a reduced energetic neutron to pion gamma ray emission in the >10 MeV band. These changes can be produced either by a strong hardening of the accelerated ion spectrum together with a relative decrease in the energetic electron spectrum, or by a pronounced change in the geometry of the particle spectrum downwards towards the photosphere. The authors review the observational evidence in terms of these two possibilities. A dramatic change in the energetic particle geometry appears to offer the simplest explanation. If true these two flares represent the first clear evidence of strong particle geometry effects within individual flares

  12. Effect of polarizable lone pair cations on the second-harmonic generation (SHG) properties of noncentrosymmetric (NCS) Bi(2-x)Y(x)TeO₅ (x = 0-0.2).

    Science.gov (United States)

    Jo, Hongil; Kim, Yeong Hun; Lee, Dong Woo; Ok, Kang Min

    2014-08-14

    Y(3+)-doped noncentrosymmetric (NCS) bismuth tellurite materials, Bi(2-x)Y(x)TeO5 (x = 0, 0.1, and 0.2), have been synthesized through standard solid-state reactions and structurally characterized by powder neutron diffraction. The reported NCS materials crystallize in the orthorhombic space group Abm2 (no. 39), and exhibit pseudo-three-dimensional frameworks that are composed of BiO3, BiO5, and TeO3 polyhedra. Detailed diffraction studies show that the cell volume of Bi(2-x)Y(x)TeO5 decreases with an increasing amount of Y(3+)on the Bi(3+) sites. However, no ordering between Bi(3+) and Y(3+) was observed in the Bi(2-x)Y(x)TeO5. Powder second-harmonic generation (SHG) measurements, using 1064 nm radiation, reveal that Bi2TeO5, Bi(1.9)Y(0.1)TeO5, and Bi(1.8)Y(0.2)TeO5 exhibit SHG efficiencies of approximately 300, 200, and 60 times that of α-SiO2, respectively. The reduction in SHG for Y(3+)-doped materials is consistent with the lack of net moment originating from polyhedra with a polarizable Bi(3+) cation.

  13. Surface passivation of HgCdTe by CdZnTe and its characteristics

    Science.gov (United States)

    Lee, T. S.; Choi, K. K.; Jeoung, Y. T.; Kim, H. K.; Kim, J. M.; Kim, Y. H.; Chang, J. M.; Song, W. S.; Kim, S. U.; Park, M. J.; Lee, S. D.

    1997-06-01

    In this paper, we report the results of capacitance-voltage measurements conducted on several metal-insulator semiconductor (MIS) capacitors in which HgCdTe surfaces are treated with various surface etching and oxidation processes. CdZnTe passivation layers were deposited on HgCdTe surfaces by thermal evaporation after the surfaces were etched with 0.5-2.0% bromine in methanol solution, or thin oxide layers (tox ˜ few ten Å) were grown on the surfaces, in order to investigate effects of the surface treatments on the electrical properties of the surfaces, as determined from capacitance-voltage (C-V) measurements at 80K and 1 MHz. A negative flat band voltage has been observed for MIS capacitors fabricated after etching of HgCdTe surfaces with bromine in methanol solutions, which is reported to make the surface Te-rich. It is inferred that residual Te on the surface is a positive charge, Te4+. C-V characteristics for MIS capacitors fabricated on oxide surfaces grown by air-exposure and electrolytic process have shown large hysteresis effects, from which it is inferred that imperfect and electrically active oxide compounds and HgTe particles near the surface become slow interface states.

  14. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español Iron-deficiency ... anemia. Blood tests to screen for iron-deficiency anemia To screen for iron-deficiency anemia, your doctor ...

  15. Precipitation of Ag{sub 2}Te in the thermoelectric material AgSbTe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Sugar, Joshua D. [Materials Physics Department, Sandia National Laboratories, Livermore, CA (United States)], E-mail: jdsugar@sandia.gov; Medlin, Douglas L. [Materials Physics Department, Sandia National Laboratories, Livermore, CA (United States)

    2009-06-10

    The microstructure of AgSbTe{sub 2}, prepared by solidification, is investigated using electron microscopy. During solidification and thermal treatment, the material separates into a two-phase mixture of a rocksalt phase, which is Ag{sub 22}Sb{sub 28}Te{sub 50}, and silver telluride, Ag{sub 2}Te. Ag{sub 2}Te formation results either from eutectic solidification (large lamellar structures), or by solid-state precipitation (fine-scale particles). The crystal structure of the AgSbTe{sub 2} phase determined by electron diffraction is consistent with a rocksalt structure that has a disordered cation sublattice. A preferred crystallographic orientation relationship at the interface between the matrix and the low-temperature monoclinic Ag{sub 2}Te phase is defined and discussed. This orientation relationship is observed for both second-phase morphologies. In both cases, the orientation relationship originates from a topotactic (cube-on-cube) alignment of the Te sublattices in the initially cubic Ag{sub 2}Te and the matrix at elevated temperature. This Te sublattice alignment is retained as the Ag{sub 2}Te undergoes a cubic-to-monoclinic transformation during cooling. This orientation relationship is observed for both second-phase morphologies.

  16. Selenium Se and tellurium Te

    International Nuclear Information System (INIS)

    Busev, A.I.; Tiptsova, V.G.; Ivanov, V.M.

    1978-01-01

    The basic methods for determining selenium and tellurium in various objects are presented. The bichromatometric determination of Te in cadmium, zinc and mercury tellurides is based on oxidation of Te(4) to (6) in H 2 SO 4 with potassium bichromate. In steels, Te is determined photometrically with the aid of KI. The determination is hindered by Fe(3), Cu(2), Bi(3) and Se(4) ions, which must be separated. The extraction-photometric determination of Te in native sulfur is carried out with the aid of 5-mercapto-3-(naphthyl-2)-1,3,4-thiadiazolthione-2 (pH=4.8-5.0). The dyed complex is readily extracted with chloroform and benzene. The spectrophotometric determination of Te in selenium is performed with the aid of 3,5-diphenylpyrazoline-1-dithiocarbamate of sodium. Te is determined in commercial indium, arsenic and their semiconductor compounds photometrically with the aid of copper diethyldithiocarbamate. The method permits determining 5x10 -5 % Te in a weighed amount of 0.5 g. The chloride complex of Te(4) with diantipyriodolpropylmethane is quantitatively extracted with dichloroethane from hydrochloric acid solutions. Thus, any amounts of Te can be separated from Se and determined photometrically. The extraction-photometric determination of Te in commercial lead and bismuth is carried out with the aid of pyrazolone derivatives, in commercial copper with the aid of diantipyridolpropylmethane, and in ores (more than 0.01% Te) with the aid of bismuthol 2. Also described is the extraction-polarographic determination of Te in sulfide ores

  17. Comparison of the microdosimetric event-size method and the twin-chamber method of separating dose into neutron and gamma components

    International Nuclear Information System (INIS)

    Stinchcomb, T.G.; Kuchnir, F.T.; Skaggs, L.S.

    1980-01-01

    Microdosimetric measurements of event-size spectra, made with a proportional counter, are being used increasingly for separation of dose components in mixed n-γ fields. Measurements in fields produced by 8.3 MeV deuteron bombardment of thick beryllium and deuterium targets were made in air and at 6 and 12 cm depth in water with a spherical tissue-equivalent (TE) proportional counter and with a pair of calibrated ion chambers (TE-TE and Mg-Ar). The dose results obtained with the two methods agree well for the neutron components, but the gamma components do not demonstrate consistent agreement. An important source of error in the microdosimetric method is the matching of the spectra measured at different gain settings to cover the large range of event sizes. The effect of this and other sources of error is analysed. (author)

  18. Pulsed neutron sources for epithermal neutrons

    International Nuclear Information System (INIS)

    Windsor, C.G.

    1978-01-01

    It is shown how accelerator based neutron sources, giving a fast neutron pulse of short duration compared to the neutron moderation time, promise to open up a new field of epithermal neutron scattering. The three principal methods of fast neutron production: electrons, protons and fission boosters will be compared. Pulsed reactors are less suitable for epithermal neutrons and will only be briefly mentioned. The design principle of the target producing fast neutrons, the moderator and reflector to slow them down to epithermal energies, and the cell with its beam tubes and shielding will all be described with examples taken from the new Harwell electron linac to be commissioned in 1978. A general comparison of pulsed neutron performance with reactors is fraught with difficulties but has been attempted. Calculation of the new pulsed source fluxes and pulse widths is now being performed but we have taken the practical course of basing all comparisons on extrapolations from measurements on the old 1958 Harwell electron linac. Comparisons for time-of-flight and crystal monochromator experiments show reactors to be at their best at long wavelengths, at coarse resolution, and for experiments needing a specific incident wavelength. Even existing pulsed sources are shown to compete with the high flux reactors in experiments where the hot neutron flux and the time-of-flight methods can be best exploited. The sources under construction can open a new field of inelastic neutron scattering based on energy transfer up to an electron volt and beyond

  19. Neutron radiography using neutron imaging plate

    International Nuclear Information System (INIS)

    Chankow, Nares; Wonglee, Sarinrat

    2008-01-01

    Full text: The aims of this research are to study properties of neutron imaging plate, to obtain a suitable condition for neutron radiography and to use the neutron imaging plate for testing of materials nondestructively. The experiments were carried out by using a neutron beam from the Thai Research Reactor TRR-1/M1 at a power of 1.2 MW. A BAS-ND 2040 FUJI neutron imaging plate and a MX125 Kodak X-ray film/Gadolinium neutron converter screen combination were tested for comparison. It was found that the photostimulated light (PSL) read out of the imaging plate was directly proportional to the exposure time. It was also found that radiography with neutron using the imaging plate was approximately 40 times faster than the conventional neutron radiography using x-ray film/Gd converter screen combination. The sensitivity of the imaging plate to gamma-rays was investigated by using gamma-rays from an 192 Ir and a 60 Co radiographic sources. The imaging plate was found to be 5-6 times less sensitive to gamma-rays than a FUJI BAS-MS 2040 gamma-ray imaging plate. Finally, some specimens were selected to be radiographed with neutrons using the imaging plate and the x-ray film/Gd converter screen combination in comparison to x-rays. Parts containing light elements could be clearly observed by the two neutron radiographic techniques. It could be concluded that the image quality from the neutron imaging plate was comparable to the conventional x-ray film/Gd converter screen combination but the exposure time could be approximately reduced by a factor of 40

  20. Microscopic analysis of shape transition in neutron-deficient Yb isotopes

    Science.gov (United States)

    Fu, Y.; Tong, H.; Wang, X. F.; Wang, H.; Wang, D. Q.; Wang, X. Y.; Yao, J. M.

    2018-01-01

    The development of nuclear collectivity in even-even Yb-170152 is studied with three types of mean-field calculations: the nonrelativistic Hartree-Fock plus BCS calculation using the Skyrme SLy4 force plus a density-dependent δ pairing force and the relativistic mean-field calculation using a point-coupling energy functional supplemented with either a density-independent δ pairing force or a separable pairing force. The low-lying states are obtained by solving a five-dimensional collective Hamiltonian with parameters determined from the three mean-field solutions. The energy surfaces, excitation energies, electric multiple transition strengths, and differential isotope shifts are presented in comparison with available data. Our results show that different treatments of pairing correlations have a significant influence on the speed of developing collectivity as the increase of neutron number. All the calculations demonstrate the important role of dynamic shape-mixing effects in resolving the puzzle in the dramatic increase of charge radius from 152Yb to 154Yb and the role of triaxiality in Yb 160 ,162 ,164 .

  1. Ultracold neutrons

    International Nuclear Information System (INIS)

    Steenstrup, S.

    Briefly surveys recent developments in research work with ultracold neutrons (neutrons of very low velocity, up to 10 m/s at up to 10 -7 eV and 10 -3 K). Slow neutrons can be detected in an ionisation chamber filled with B 10 F 3 . Very slow neutrons can be used for investigations into the dipole moment of neutrons. Neutrons of large wave length have properties similar to those of light. The limit angle for total reflection is governed by the wave length and by the material. Total reflection can be used to filter ultracold neutrons out of the moderator material of a reactor. Total reflection can also be used to store ultracold neutrons but certain problems with storage have not yet been clarified. Slow neutrons can be made to lose speed in a neutron turbine, and come out as ultracold neutrons. A beam of ultracold neutrons could be used in a neutron microscope. (J.S.)

  2. Basic research of neutron radiography using cold neutron beam

    International Nuclear Information System (INIS)

    Oda, Masahiro; Tamaki, Masayoshi; Tasaka, Kanji

    1995-01-01

    As the result of demanding high quality images, now the nuclear reactors which can supply stably intense neutron beam have become the most general neutron source for radiography. For the purpose, mostly thermal neutrons have been used, but it is indispensable to use other neutrons than thermal neutrons for advancing neutron radiography technology and expanding the application fields. The radiography using cold neutrons is most behind in the development because the suitable neutron source was not available in Japan. The neutron sources for exclusively obtaining intense cold neutron beam were installed in the Kyoto University reactor in 1986 and in the JRR-3M of Japan Atomic Energy Research Institute in 1991. Basically as neutron energy lowers, the cross section of substances increases. In certain crystalline substances, the Bragg cutoff arises. The removal of scattered neutrons, the measurement of parallelism of beam and the relation of the thickness of objects with the transmissivity of cold neutrons are described. The imaging by TV method and the cold neutron CT in the CNRF and the simplified neutron CT by film method are reported. (K.I.)

  3. Breast MRI at very short TE (minTE). Image analysis of minTE sequences on non-fat-saturated, subtracted T1-weighted images

    Energy Technology Data Exchange (ETDEWEB)

    Wenkel, Evelyn; Janka, Rolf; Kaemmerer, Nadine; Uder, Michael; Hammon, Matthias; Brand, Michael [Univ. Hospital Erlangen (Germany). Dept. of Radiology; Geppert, Christian [Siemens Healthcare GmbH, Erlangen (Germany); Hartmann, Arndt [Univ. Hospital Erlangen (Germany). Dept. of Pathology

    2017-02-15

    The aim was to evaluate a minimum echo time (minTE) protocol for breast magnetic resonance imaging (MRI) in patients with breast lesions compared to a standard TE (nTE) time protocol. Breasts of 144 women were examined with a 1.5 Tesla MRI scanner. Additionally to the standard gradient-echo sequence with nTE (4.8 ms), a variant with minimum TE (1.2 ms) was used in an interleaved fashion which leads to a better temporal resolution and should reduce the scan time by approximately 50%. Lesion sizes were measured and the signal-to-noise ratio (SNR) as well as the contrast-to-noise ratio (CNR) were calculated. Subjective confidence was evaluated using a 3-point scale before looking at the nTE sequences (1 = very sure that I can identify a lesion and classify it, 2 = quite sure that I can identify a lesion and classify it, 3 = definitely want to see nTE for final assessment) and the subjective image quality of all examinations was evaluated using a four-grade scale (1 = sharp, 2 = slight blur, 3 = moderate blur and 4 = severe blur/not evaluable) for lesion and skin sharpness. Lesion morphology and contrast enhancement were also evaluated. With minTE sequences, no lesion was rated with ''definitely want to see nTE sequences for final assessment''. The difference of the longitudinal and transverse diameter did not differ significantly (p>0.05). With minTE, lesions and skin were rated to be significantly more blurry (p<0.01 for lesions and p<0.05 for skin). There was no difference between both sequences with respect to SNR, CNR, lesion morphology, contrast enhancement and detection of multifocal disease. Dynamic breast MRI with a minTE protocol is feasible without a major loss of information (SNR, CNR, lesion morphology, contrast enhancement and lesion sizes) and the temporal resolution can be increased by a factor of 2 using minTE sequences.

  4. Breast MRI at very short TE (minTE). Image analysis of minTE sequences on non-fat-saturated, subtracted T1-weighted images

    International Nuclear Information System (INIS)

    Wenkel, Evelyn; Janka, Rolf; Kaemmerer, Nadine; Uder, Michael; Hammon, Matthias; Brand, Michael; Hartmann, Arndt

    2017-01-01

    The aim was to evaluate a minimum echo time (minTE) protocol for breast magnetic resonance imaging (MRI) in patients with breast lesions compared to a standard TE (nTE) time protocol. Breasts of 144 women were examined with a 1.5 Tesla MRI scanner. Additionally to the standard gradient-echo sequence with nTE (4.8 ms), a variant with minimum TE (1.2 ms) was used in an interleaved fashion which leads to a better temporal resolution and should reduce the scan time by approximately 50%. Lesion sizes were measured and the signal-to-noise ratio (SNR) as well as the contrast-to-noise ratio (CNR) were calculated. Subjective confidence was evaluated using a 3-point scale before looking at the nTE sequences (1 = very sure that I can identify a lesion and classify it, 2 = quite sure that I can identify a lesion and classify it, 3 = definitely want to see nTE for final assessment) and the subjective image quality of all examinations was evaluated using a four-grade scale (1 = sharp, 2 = slight blur, 3 = moderate blur and 4 = severe blur/not evaluable) for lesion and skin sharpness. Lesion morphology and contrast enhancement were also evaluated. With minTE sequences, no lesion was rated with ''definitely want to see nTE sequences for final assessment''. The difference of the longitudinal and transverse diameter did not differ significantly (p>0.05). With minTE, lesions and skin were rated to be significantly more blurry (p<0.01 for lesions and p<0.05 for skin). There was no difference between both sequences with respect to SNR, CNR, lesion morphology, contrast enhancement and detection of multifocal disease. Dynamic breast MRI with a minTE protocol is feasible without a major loss of information (SNR, CNR, lesion morphology, contrast enhancement and lesion sizes) and the temporal resolution can be increased by a factor of 2 using minTE sequences.

  5. Neutron stars as cosmic neutron matter laboratories

    International Nuclear Information System (INIS)

    Pines, D.

    1986-01-01

    Recent developments which have radically changed our understanding of the dynamics of neutron star superfluids and the free precession of neutron stars are summarized, and the extent to which neutron stars are cosmic neutron matter laboratories is discussed. 17 refs., 1 tab

  6. The fingerprint of Te-rich and stoichiometric Bi2Te3 nanowires by Raman spectroscopy

    Science.gov (United States)

    Rodríguez-Fernández, Carlos; Manzano, Cristina V.; Romero, Aldo H.; Martín, Jaime; Martín-González, Marisol; Morais de Lima, Mauricio, Jr.; Cantarero, Andrés

    2016-02-01

    We unambiguously show that the signature of Te-rich bismuth telluride is the appearance of three new peaks in the Raman spectra of Bi2Te3, located at 88, 117 and 137 cm-1. For this purpose, we have grown stoichiometric Bi2Te3 nanowires as well as Te-rich nanowires. The absence of these peaks in stoichiometric nanowires, even in those with the smallest diameter, shows that they are not related to confinement effects or the lack of inversion symmetry, as stated in the literature, but to the existence of Te clusters. These Te clusters have been found in non-stoichiometric samples by high resolution electron microscopy, while they are absent in stoichiometric samples. The Raman spectra of the latter corresponds to the one for bulk Bi2Te3. The intensity of these Raman peaks are clearly correlated to the Te content. In order to ensure statistically meaningful results, we have investigated several regions from every sample.

  7. AsTeRICS.

    Science.gov (United States)

    Drajsajtl, Tomáš; Struk, Petr; Bednárová, Alice

    2013-01-01

    AsTeRICS - "The Assistive Technology Rapid Integration & Construction Set" is a construction set for assistive technologies which can be adapted to the motor abilities of end-users. AsTeRICS allows access to different devices such as PCs, cell phones and smart home devices, with all of them integrated in a platform adapted as much as possible to each user. People with motor disabilities in the upper limbs, with no cognitive impairment, no perceptual limitations (neither visual nor auditory) and with basic skills in using technologies such as PCs, cell phones, electronic agendas, etc. have available a flexible and adaptable technology which enables them to access the Human-Machine-Interfaces (HMI) on the standard desktop and beyond. AsTeRICS provides graphical model design tools, a middleware and hardware support for the creation of tailored AT-solutions involving bioelectric signal acquisition, Brain-/Neural Computer Interfaces, Computer-Vision techniques and standardized actuator and device controls and allows combining several off-the-shelf AT-devices in every desired combination. Novel, end-user ready solutions can be created and adapted via a graphical editor without additional programming efforts. The AsTeRICS open-source framework provides resources for utilization and extension of the system to developers and researches. AsTeRICS was developed by the AsTeRICS project and was partially funded by EC.

  8. Determination of Inorganic Elements in White Rice by Neutron Activation Analysis

    International Nuclear Information System (INIS)

    Moon, J. H.; Kim, S. H.; Lim, J. M.; Lee, Y. N.; Chung, Y. S.

    2011-01-01

    Rice is a staple food and provides an important information of mineral supplement as well as a large portion of calorie for Korean. As scientists have focused their researches on health impacts caused by mineral nutrient deficiency and hazardous elements, public concerns about mineral intake by dietary food is rising. The objectives of this study were to determine inorganic elemental contents in white rice by neutron activation analysis(NAA) and to assist the evaluation of nutritional and harmful status for Korean people

  9. Local atomic interdiffusion in CdTe/HgCdTe multilayered structures

    International Nuclear Information System (INIS)

    Kim, Y.; Ourmazd, A.; Feldman, R.D.; Rentschler, J.A.; Taylor, D.W.; Austin, R.F.

    1989-01-01

    The authors combine chemical lattice imaging with digital pattern recognition to study atomic interdiffusion at individual CdTe/HgCdTe interfaces in multi-quantum well structures. In this way they obtain quantitative composition profiles for as grown samples, and investigate their development as a function of annealing temperature. The authors' results indicate that interdiffusion depends on the position of the quantum well with respect to the surface, beginning first at quantum wells close to the surface, and proceeding towards the substrate. The authors' approach allows the quantification of interdiffusion as a function of time, temperature, and distance from the surface. The implications of these results for the stability of CdTe/HgCdTe structures, and the interpretation of X-ray data are discussed

  10. The microstructure network and thermoelectric properties of bulk (Bi,Sb)2Te3

    DEFF Research Database (Denmark)

    Xie, Wenjie; Hitchcock, Dale A.; Kang, Hye J.

    2012-01-01

    We report small-angle neutron scattering studies on the microstructure network in bulk (Bi,Sb)(2)Te-3 synthesized by the melt-spinning (MS) and the spark-plasma-sintering (SPS) process. We find that rough interfaces of multiscale microstructures generated by the MS are responsible for the large...... reduction of both lattice thermal conductivity and electrical conductivity. Our study also finds that subsequent SPS forms a microstructure network of similar to 10 nm thick lamellae and smooth interfaces between them. This nanoscale microstructure network with smooth interfaces increases electrical...... conductivity while keeping a low thermal conductivity, making it an ideal microstructure for high thermoelectric efficiency....

  11. Study of rare neutron induced processes and coincidence analyses to identify and reduce background contributions in the COBRA experiment

    International Nuclear Information System (INIS)

    Timm, Jan Horst Karl

    2015-11-01

    The aim of the COBRA experiment is the observation of neutrinoless double-beta decay, primarily of the isotope 116 Cd. The applied semiconductor detectors of cadmium zinc telluride that are 90% to be enriched enable both the detection and the source of this decay. The half-lives of decays of this kind are expected in the range of more than 10 26 years. Therefore, the reduction of contributions to the background is of decisive importance. The main subjects of this work are, on the one hand, the time synchronization of the data, which provides the basis for coincidence analysis. This analysis method has access not only to identification of contributions to the background, but also to observe decays involving positron annihilation and decays into excited states. In this study, the intrinsic detector contamination of some decay products of 238 U and 232 Th was measured and sensitivities to the half-lives of the decays like 120 Te and 128 Te in each case to the first excited state of daughter products are given. On the other hand, qualitative studies on the importance of neutrons in the COBRA experiment were conducted. These have shown that fast neutrons, thus with energies greater than 10 keV, only result in an insignificant contribution to the background for the detection of neutrinoless double-beta decay of the 116 Cd. Previous studies have also shown that the thermal neutron flux can be in situ determined by coincidence analysis.

  12. Simple one-pot aqueous synthesis of CdHgTe nanocrystals using sodium tellurite as the Te source

    International Nuclear Information System (INIS)

    Shen, Zhitao; Luo, Chunhua; Huang, Rong; Wang, Yiting; Peng, Hui; Travas-sejdic, Jadranka

    2014-01-01

    In this work, we systematically investigated the one-pot aqueous synthesis conditions of CdHgTe nanocrystals (NCs) using sodium tellurite (Na 2 TeO 3 ) as the Te source, and found that the added content of Hg 2+ and the initial pH value of reaction solutions significantly affected the photoluminescence quantum yield (PL QY) of alloyed CdHgTe NCs. When the concentration of Cd was 1.0 mmol L −1 , the mole ratio of Cd/Te/Hg/MPA was 1:0.5:0.05:2.4, and the initial pH value of the reaction solution was about 8.78, the PL QY of as-prepared CdHgTe NCs was up to 45%. Characterization by HRTEM and XRD confirmed the crystalline nature of CdHgTe NCs. Compared to other synthetic approaches of CdHgTe NCs, our experimental results indicate that Na 2 TeO 3 could be an attractive alternative Te source to directly synthesize CdHgTe NCs in aqueous media. - Highlights: • A one-pot method was developed for the synthesis of highly luminescent CdHgTe nanocrystals (NCs). • Sodium tellurite was used as the Te source. • The quantum yield reached up to 45%. • The experimental conditions were optimized and the prepared CdHgTe NCs were characterized

  13. PharmTeX: a LaTeX-Based Open-Source Platform for Automated Reporting Workflow.

    Science.gov (United States)

    Rasmussen, Christian Hove; Smith, Mike K; Ito, Kaori; Sundararajan, Vijayakumar; Magnusson, Mats O; Niclas Jonsson, E; Fostvedt, Luke; Burger, Paula; McFadyen, Lynn; Tensfeldt, Thomas G; Nicholas, Timothy

    2018-03-16

    Every year, the pharmaceutical industry generates a large number of scientific reports related to drug research, development, and regulatory submissions. Many of these reports are created using text processing tools such as Microsoft Word. Given the large number of figures, tables, references, and other elements, this is often a tedious task involving hours of copying and pasting and substantial efforts in quality control (QC). In the present article, we present the LaTeX-based open-source reporting platform, PharmTeX, a community-based effort to make reporting simple, reproducible, and user-friendly. The PharmTeX creators put a substantial effort into simplifying the sometimes complex elements of LaTeX into user-friendly functions that rely on advanced LaTeX and Perl code running in the background. Using this setup makes LaTeX much more accessible for users with no prior LaTeX experience. A software collection was compiled for users not wanting to manually install the required software components. The PharmTeX templates allow for inclusion of tables directly from mathematical software output as well and figures from several formats. Code listings can be included directly from source. No previous experience and only a few hours of training are required to start writing reports using PharmTeX. PharmTeX significantly reduces the time required for creating a scientific report fully compliant with regulatory and industry expectations. QC is made much simpler, since there is a direct link between analysis output and report input. PharmTeX makes available to report authors the strengths of LaTeX document processing without the need for extensive training. Graphical Abstract ᅟ.

  14. Excitons in tunnel coupled CdTe and (Cd,Mn)Te quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Terletskii, Oleg; Ryabchenko, Sergiy; Tereshchenko, Oleksandr [Institute of Physics NASU, pr. Nauki 46, 03680 Kyiv (Ukraine); Sugakov, Volodymyr; Vertsimakha, Ganna [Institute for Nuclear Research NASU, pr. Nauki 47, 03680 Kyiv (Ukraine); Karczewski, Grzegorz [Institute of Physics PAS, Al. Lotnikow 32/46, PL-02-668 Warsaw (Poland)

    2017-05-15

    The photoluminescence (PL) from structures containing Cd{sub 0.95}Mn{sub 0.05}Te and CdTe quantum wells (QWs) separated by a narrow (1.94 nm) barrier was studied. The PL lines of comparable intensities from several possible exciton states were observed simultaneously at energy distances substantially exceeding kT. This means that the energy transfer in the studied systems is slower than the radiative recombination of the confined excitons. For the CdTe QW width of about 8.7-9 nm, indirect excitons with the electron and heavy hole chiefly localized in the CdTe and Cd{sub 1-x}Mn{sub x}Te QWs, respectively, were detected in the magnetic field. These indirect excitons have PL energy of about 10-20 meV above the PL line of the direct excitons in the CdTe QW. The observation of the PL from the indirect excitons which are not the lowest excitations in the structure is a distinctive feature of the system. Photoluminescence intensity dependence on the energy and the magnetic field. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Polarized neutrons

    International Nuclear Information System (INIS)

    Williams, W.G.

    1988-01-01

    The book on 'polarized neutrons' is intended to inform researchers in condensed matter physics and chemistry of the diversity of scientific problems that can be investigated using polarized neutron beams. The contents include chapters on:- neutron polarizers and instrumentation, polarized neutron scattering, neutron polarization analysis experiments and precessing neutron polarization. (U.K.)

  16. Investigations on the system Te/O/Br

    International Nuclear Information System (INIS)

    Oppermann, H.; Kunze, G.; Wolf, E.; Titov, V.A.; Kokovin, G.A.

    1978-01-01

    The melting point diagram of the system TeBr 4 -TeO 2 was obtained by total pressure measurements and DTA measurements. A congruent melting composition Te 6 O 11 Br 2 exists, the melting point is 570 0 C. The enthalpy of formation and the standard entropy of the species TeOBr 2 ,g was derived from measurements of the total pressure over Te 6 O 11 Br 2 /TeBr 4 and from the transport behaviour of the TeO 2 with Br 2 . From the decomposition-pressure measurements over Te 6 O 11 Br 2 /TeO 2 follow the partial pressures. The enthalpy of formation ΔH 0 (Te 6 O 11 Br 2 ,f,298) -453.5 kcal/Mol was obtained from the enthalpy of solution. The transport-behaviour of TeO 2 with HBr, TeBr 4 and Br 2 and that of Te 6 O 11 Br 2 is clear with the thermodynamic data of TeOBr 2 . (author)

  17. New chalcogenide glasses in the CdTe-AgI-As{sub 2}Te{sub 3} system

    Energy Technology Data Exchange (ETDEWEB)

    Kassem, M. [Univ. Picardie Jules Verne, F-80000 Amiens (France); Le Coq, D., E-mail: david.lecoq@univ-littoral.fr [Univ. Lille Nord de France, F-59000 Lille (France); ULCO, LPCA, EA 4493, F-59140 Dunkerque (France); Boidin, R.; Bychkov, E. [Univ. Lille Nord de France, F-59000 Lille (France); ULCO, LPCA, EA 4493, F-59140 Dunkerque (France)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Determination of the glass-forming region in the pseudo-ternary CdTe-AgI-As{sub 2}Te{sub 3} system. Black-Right-Pointing-Pointer Characterization of macroscopic properties of the new CdTe-AgI-As{sub 2}Te{sub 3} glasses. Black-Right-Pointing-Pointer Characterization of the total conductivity of CdTe-AgI-As{sub 2}Te{sub 3} glasses. Black-Right-Pointing-Pointer Comparison between the selenide and telluride equivalent systems. -- Abstract: Chalcogenide glasses in the pseudo-ternary CdTe-AgI-As{sub 2}Te{sub 3} system were synthesized and the glass-forming range was determined. The maximum content of CdTe in this glass system was found to be equal to 15 mol.%. The macroscopic characterizations of samples have consisted in Differential Scanning Calorimetry, density, and X-ray diffraction measurements. The cadmium telluride addition does not generate any significant change in the glass transition temperature but the resistance of binary AgI-As{sub 2}Te{sub 3} glasses towards crystallisation is estimated to be decreasing on the base of {Delta}T = T{sub x} - T{sub g} parameter. The total electrical conductivity {sigma} was measured by complex impedance spectroscopy. First, the CdTe additions in the (AgI){sub 0.5}(As{sub 2}Te{sub 3}){sub 0.5} host glass, (CdTe){sub x}(AgI){sub 0.5-x/2}(As{sub 2}Te{sub 3}){sub 0.5-x/2} lead to a conductivity decrease at x {<=} 0.05. Then, the behaviour is reversed at 0.05 {<=} x {<=} 0.15. The obtained results are discussed by comparison with the equivalent selenide system.

  18. Neutron spectra produced by moderating an isotopic neutron source

    International Nuclear Information System (INIS)

    Carrillo Nunnez, Aureliano; Vega Carrillo, Hector Rene

    2001-01-01

    A Monte Carlo study has been carried out to determine the neutron spectra produced by an isotopic neutron source inserted in moderating media. Most devices used for radiation protection have a response strongly dependent on neutron energy. ISO recommends several neutron sources and monoenergetic neutron radiations, but actual working situations have broad spectral neutron distributions extending from thermal to MeV energies, for instance, near nuclear power plants, medical applications accelerators and cosmic neutrons. To improve the evaluation of the dosimetric quantities, is recommended to calibrate the radiation protection devices in neutron spectra which are nearly like those met in practice. In order to complete the range of neutron calibrating sources, it seems useful to develop several wide spectral distributions representative of typical spectra down to thermal energies. The aim of this investigation was to use an isotopic neutron source in different moderating media to reproduce some of the neutron fields found in practice. MCNP code has been used during calculations, in these a 239PuBe neutron source was inserted in H2O, D2O and polyethylene moderators. Moderators were modeled as spheres and cylinders of different sizes. In the case of cylindrical geometry the anisotropy of resulting neutron spectra was calculated from 0 to 2 . From neutron spectra dosimetric features were calculated. MCNP calculations were validated by measuring the neutron spectra of a 239PuBe neutron source inserted in a H2O cylindrical moderator. The measurements were carried out with a multisphere neutron spectrometer with a 6LiI(Eu) scintillator. From the measurements the neutron spectrum was unfolded using the BUNKIUT code and the UTA4 response matrix. Some of the moderators with the source produce a neutron spectrum close to spectra found in actual applications, then can be used during the calibration of radiation protection devices

  19. Matrix-controlled morphology evolution of Te inclusions in CdZnTe single crystal

    International Nuclear Information System (INIS)

    He, Yihui; Jie, Wanqi; Xu, Yadong; Wang, Tao; Zha, Gangqiang; Yu, Pengfei; Zheng, Xin; Zhou, Yan; Liu, Hang

    2012-01-01

    The fine morphologies of microscale Te inclusions in CdZnTe single crystal were investigated to reveal their shape evolution. Such inclusions from crystal ingots with different post-growth cooling rates were analyzed using scanning electron microscopy after surface treatment. A tetrakaidecahedron model embodying {1 0 0} and {1 1 1} matrix facets was developed to interpret the form of the Te inclusions. An entire shape evolution process was also proposed where the final configuration of the Te inclusions was a tetrahedron comprising {1 1 1}B facets.

  20. Evaluation of Tp-Te Interval and Tp-Te/QT Ratio in Patients with Coronary Slow Flow Tp-Te/QT Ratio and Coronary Slow Flow.

    Science.gov (United States)

    Tenekecioglu, Erhan; Karaagac, Kemal; Yontar, Osman Can; Agca, Fahriye Vatansever; Ozluk, Ozlem Arican; Tutuncu, Ahmet; Arslan, Burhan; Yilmaz, Mustafa

    2015-06-01

    Coronary slow flow (CSF) phenomenon is described by angiographically normal coronary arteries with delayed opacification of the distal vasculature. Several studies have suggested that the interval from the peak to the end of the electrocardiographic T wave (Tp-Te) may correspond to the transmural dispersion of the repolarization and that increased Tp-Te interval and Tp-Te/QT ratio are associated with malignant ventricular arrhythmias. The aim of this study was to evaluate the ventricular repolarization by using Tp-Te interval and Tp-Te/QT ratio in patients with CSF. This study included 50 CSF patients (40 male, mean age 48.6±12.5 years) and 40 control individuals (23 male, mean age 47.8±12.5 years). Tp-Te interval and Tp-Te/QT ratio were measured from the 12-lead electrocardiogram. These parameters were compared in groups. Baseline characteristics of the study groups were comparable. In electrocardiographic parameters analysis, QT and corrected QT were similar in CSF patients compared to the controls (357±35.2 vs 362±38.0 milliseconds and 419±25.8 vs 430±44.2 milliseconds, all p value >0.05). Tp-Te interval, Tp-Te/QT and Tp-Te/QTc ratio were significantly higher in CSF patients (85±13.7 vs 74±9.9 milliseconds and 0.24±0.03 vs 0.20±0.02 and 0.20±0.03 vs 0.17±0.02 all p value ratio are prolonged in patients with CSF.

  1. Trace element determination in fingernails, hair and blood serum in patients with Crohn's disease using neutron activation analysis

    International Nuclear Information System (INIS)

    Buschmann, H.

    1984-01-01

    The determination of trace elements and electrolyte concentrations in blood serum, hair and fingernails of 16 patients with Crohn's disease was carried out by means of instrumental neutron activation analysis. In the serum a significant decline in the zinc content could be registered, while the remaining trace elements remained in the normal range. The parenteral nutrition also showed a zinc deficiency. There was, however, also an iron deficiency. The studies of the hair and fingernails gave the following results: Rubidium and antimony in the normal range; zinc, selenium, iron and cobalt below normal values. (orig./PW) [de

  2. Neutron beam design for low intensity neutron and gamma-ray radioscopy using small neutron sources

    CERN Document Server

    Matsumoto, T

    2003-01-01

    Two small neutron sources of sup 2 sup 5 sup 2 Cf and sup 2 sup 4 sup 1 Am-Be radioisotopes were used for design of neutron beams applicable to low intensity neutron and gamma ray radioscopy (LINGR). In the design, Monte Carlo code (MCNP) was employed to generate neutron and gamma ray beams suited to LINGR. With a view to variable neutron spectrum and neutron intensity, various arrangements were first examined, and neutron-filter, gamma-ray shield and beam collimator were verified. Monte Carlo calculations indicated that with a suitable filter-shield-collimator arrangement, thermal neutron beam of 3,900 ncm sup - sup 2 s sup - sup 1 with neutron/gamma ratio of 7x10 sup 7 , and 25 ncm sup - sup 2 s sup - sup 1 with very large neutron/gamma ratio, respectively, could be produced by using sup 2 sup 5 sup 2 Cf(122 mu g) and a sup 2 sup 4 sup 1 Am-Be(37GBq)radioisotopes at the irradiation port of 35 cm from the neutron sources.

  3. Effects of Te inclusions on charge-carrier transport properties in CdZnTe radiation detectors

    International Nuclear Information System (INIS)

    Gu, Yaxu; Rong, Caicai; Xu, Yadong; Shen, Hao; Zha, Gangqiang; Wang, Ning; Lv, Haoyan; Li, Xinyi; Wei, Dengke; Jie, Wanqi

    2015-01-01

    Highlights: • This work reveals the behaviors of Te inclusion in affecting charge-carrier transport properties in CdZnTe detectors for the first time and analysis the mechanism therein. • The results show that charge collection efficiencies in Te inclusion degraded regions experience fast ascent under low biases and slow descent at high applied biases, which deviates from the Hecht rule. • This phenomenon is attributed to the competitive influence of two mechanisms under different biases, namely charge carrier trapping due to uniformly distributed point defects and Te inclusion induced transient charge loss. • A modified Hecht equation is further proposed to explain the effects of high-density localized defects, say Te inclusions, on the charge collection efficiency. • We believe that this research has wide appeal to analyze the macroscopic defects and their influence on charge transport properties in semiconductor radiation detectors. - Abstract: The influence of tellurium (Te) inclusions on the charge collection efficiency in cadmium zinc telluride (CdZnTe or CZT) detectors has been investigated using ion beam induced charge (IBIC) technique. Combining the analysis of infrared transmittance image, most of the low charge collection areas in the IBIC images prove the existence of Te inclusions. To further clarify the role of Te inclusions on charge transport properties, bias dependent local IBIC scan was performed on Te inclusion related regions from 20 V to 500 V. The result shows that charge collection efficiencies in Te inclusion degraded regions experience fast ascent under low biases and slow descent at high applied biases, which deviates from Hecht rule. This behavior is attributed to the competitive influence of two mechanisms under different biases, namely charge carrier trapping due to uniformly distributed point defects and Te inclusion induced transient charge loss. A modified Hecht equation is further proposed to explain the effects of high

  4. Neutron cooling and cold-neutron sources (1962); Refroidissement des neutrons et sources de neutrons froids (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Jacrot, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-07-01

    Intense cold-neutron sources are useful in studying solids by the inelastic scattering of neutrons. The paper presents a general survey covering the following aspects: a) theoretical considerations put forward by various authors regarding thermalization processes at very low temperatures; b) the experiments that have been carried out in numerous laboratories with a view to comparing the different moderators that can be used; c) the cold neutron sources that have actually been produced in reactors up to the present time, and the results obtained with them. (author) [French] Des sources intenses de neutrons froids sont utiles pour l'etude des solides par diffusion inelastique des neutrons. On presente une revue d'ensemble: a) des considerations theoriques faites par divers auteurs sur les processus de thermalisation a tres basse temperature; b) des experiences faites dans de nombreux laboratoires pour comparer les divers moderateurs possibles; c) des sources de neutrons froids effectivement realisees dans des piles a ce jour, et des resultats obtenus avec ces sources. (auteur)

  5. Structural and electric properties of AgGaTe{sub 2} layers prepared using mixed source of Ag{sub 2}Te and Ga{sub 2}Te{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Uruno, Aya [Department of Electrical Engineering and Bioscience, Waseda University, Tokyo (Japan); Kobayashi, Masakazu [Department of Electrical Engineering and Bioscience, Waseda University, Tokyo (Japan); Kagami Memorial Research Institute for Materials Science and Technology, Waseda University, Tokyo (Japan)

    2017-01-15

    AgGaTe{sub 2} layers were prepared on Si substrates by a closed space sublimation method using a mixed powder source of Ag{sub 2}Te and Ga{sub 2}Te{sub 3}. Ag{sub 2}Te buffer layer deposition was introduced to eliminate melt-back etching. The effect of the molar ratio of Ag{sub 2}Te and Ga{sub 2}Te{sub 3} in the mixed source on the crystallinity of the AgGaTe{sub 2} layer was investigated. The composition and the phase of the layer was found to change depending on the molar ratio in the deposits, which could be controlled by the source molar ratio along with the Ag{sub 2}Te buffer layer thickness. It was confirmed that (112) oriented uniform AgGaTe{sub 2} layer with an abrupt interface between AgGaTe{sub 2} and Si was formed after those parameters were tuned. The obtained layer exhibited the acceptor concentration of around 2.5 x 10{sup 16} cm{sup -3}. A solar cell was fabricated using the p-AgGaTe{sub 2}/n-Si heterojunction, and exhibited a conversion efficiency of 1.15%. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español Iron-deficiency anemia is a ... address the cause of your iron deficiency, such as any underlying bleeding. If undiagnosed or untreated, iron- ...

  7. Correction of diagnostic x-ray spectra measured with CdTe and CdZnTe detectors

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, M [Osaka Univ., Suita (Japan). Medical School; Kanamori, H; Toragaito, T; Taniguchi, A

    1996-07-01

    We modified the formula of stripping procedure presented by E. Di. Castor et al. We added the Compton scattering and separated K{sub {alpha}} radiation of Cd and Te (23 and 27keV, respectively). Using the new stripping procedure diagnostic x-ray spectra (object 4mm-Al) of tube voltage 50kV to 100kV for CdTe and CdZnTe detectors are corrected with comparison of those spectra for the Ge detector. The corrected spectra for CdTe and CdZnTe detectors coincide with those for Ge detector at lower tube voltage than 70kV. But the corrected spectra at higher tube voltage than 70kV do not coincide with those for Ge detector. The reason is incomplete correction for full energy peak efficiencies of real CdTe and CdZnTe detectors. (J.P.N.)

  8. Produção do conhecimento sobre o ensino de geografia para pessoas com deficiência

    Directory of Open Access Journals (Sweden)

    Taís Buch Pastoriza

    2015-08-01

    Full Text Available A matrícula de pessoas com deficiência nas escolas regulares em diferentes etapas tem crescido nos últimos anos e com isso também as pesquisas na interface da educação especial com as outras áreas do conhecimento. O objetivo deste estudo foi analisar a produção de pesquisas sobre ensino de geografia para pessoas com deficiência, com foco na visual, bem como analisar os temas pesquisados e as Instituições de Ensino Superior onde as pesquisas se realizaram com vistas a apontar os desafios e as possibilidades para futuros trabalhos. O referencial teórico sobre análise de produção científica pautou-se em Bueno (2010 e Silva e Gamboa (2011. O levantamento da produção foi realizado no banco de teses da Capes, e os descritores utilizados foram: inclusão, deficiência, cegueira e ensino de geografia. Os resultados dessa análise mostram que a escolarização das pessoas com deficiência tem sido um tema em crescimento nas pesquisas dos últimos anos, mas que o enfoque das pesquisas está nas metodologias de ensino. Também há uma indicação para uma possível diversificação nas deficiências estudadas e nas Instituições de Ensino Superior.

  9. X-ray diffraction study of epitaxial heterostructures of II-VI CdTe and ZnTe semiconductors; Etude par diffraction de rayons X d`heterostructures epitaxiees a base des semi-conducteurs II-VI CdTe et ZnTe

    Energy Technology Data Exchange (ETDEWEB)

    Bouchet-Boudet, N.

    1996-10-07

    This work deals with the structural study of II-VI semiconductor (CdTe and ZnTe) heterostructures by X-ray diffraction and reflectivity. These heterostructures have a high lattice parameter misfit and are grown by Molecular Beam Epitaxy. Two main subjects are developed: the characterization of ZnTe wires, grown by step propagation on a CdTe (001) vicinal surface, and the study of the vertical correlations in Cd{sub 0.8}Zn{sub 0.2}Te / CdTe superlattices and superlattices made of ZnTe fractional layers spaced by CdTe. The growth of organised system is up to date; its aim is to realize quantum boxes (or wires) superlattices which are laterally and vertically ordered. The deformation along the growth axis induced by a ZnTe fractional layer inserted in a CdTe matrix is modelled, in the kinematical approximation, to reproduce the reflectivity measured around the substrate (004) Bragg peak. The lateral periodicity of the wires, deposited on a vicinal surface is a new and difficult subject. Some results are obtained on a vertical superlattice grown on a 1 deg. mis-cut surface. The in-plane and out-of-plane correlation lengths of a Cd{sub 0.8}Zn{sub 0.2}Te / CdTe superlattice are deduced from the diffused scattered intensity measured at grazing incidence. The calculations are made within the `distorted Wave Born Approximation`. The vertical correlation in ZnTe boxes (or wines) superlattices can be measured around Bragg peaks. It is twice bigger in a superlattice grown on a 2 deg. mis-cut substrate than a nominal one. (author). 74 refs.

  10. A new type of one-dimensional compound: Structure of Nb4(Te2)4Te4I

    International Nuclear Information System (INIS)

    Deng Shuiquan; Zhuang Honghui; Lu Canzhong; Huang Jinshun; Huang Jingling

    1993-01-01

    The new infinite-chain niobium telluride iodide has been prepared by reaction of the elements at 893 K. Nb 4 (Te 2 ) 4 Te 4 I represents a new one-dimensional structure type. The structure consists of [Nb 4 (Te 2 ) 4 Te 4 I] ∞ chains which are formed by the four-nuclear butterfly cluster units 'Nb 4 (Te 2 ) 4 Te 4 ' with the I atoms bridging between different cluster units. (orig.)

  11. High thermoelectric potential of Bi{sub 2}Te{sub 3} alloyed GeTe-rich phases

    Energy Technology Data Exchange (ETDEWEB)

    Madar, Naor; Givon, Tom; Mogilyansky, Dmitry; Gelbstein, Yaniv [Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel)

    2016-07-21

    In an attempt to reduce our reliance on fossil fuels, associated with severe environmental effects, the current research is focused on the identification of the thermoelectric potential of p-type (GeTe){sub 1−x}(Bi{sub 2}Te{sub 3}){sub x} alloys, with x values of up to 20%. Higher solubility limit of Bi{sub 2}Te{sub 3} in GeTe, than previously reported, was identified around ∼9%, extending the doping potential of GeTe by the Bi{sub 2}Te{sub 3} donor dopant, for an effective compensation of the high inherent hole concentration of GeTe toward thermoelectrically optimal values. Around the solubility limit of 9%, an electronic optimization resulted in an impressive maximal thermoelectric figure of merit, ZT, of ∼1.55 at ∼410 °C, which is one of the highest ever reported for any p-type GeTe-rich alloys. Beyond the solubility limit, a Fermi Level Pinning effect of stabilizing the Seebeck coefficient was observed in the x = 12%–17% range, leading to stabilization of the maximal ZTs over an extended temperature range; an effect that was associated with the potential of the governed highly symmetric Ge{sub 8}Bi{sub 2}Te{sub 11} and Ge{sub 4}Bi{sub 2}Te{sub 7} phases to create high valence band degeneracy with several bands and multiple hole pockets on the Fermi surface. At this compositional range, co-doping with additional dopants, creating shallow impurity levels (in contrast to the deep lying level created by Bi{sub 2}Te{sub 3}), was suggested for further electronic optimization of the thermoelectric properties.

  12. Low-temperature sintering and microwave dielectric properties of Al2TeO6–TeO2 ceramics

    International Nuclear Information System (INIS)

    Kagomiya, Isao; Kodama, Yuichiro; Shimizu, Yukihiro; Kakimoto, Ken-ichi; Ohsato, Hitoshi; Miyauchi, Yasuharu

    2015-01-01

    Highlights: • This is the first study of dielectric properties of Al 2 TeO 6 –TeO 2 sintered at 900 °C. • The sintering at 900 °C contributed to densification, but it causes TeO 2 evaporation. • The annealing at 750 °C was effective for the further densification. • The both ε r and Q · f in the Al 2 TeO 6 –TeO 2 were improved with the annealing. - Abstract: We propose Al 2 TeO 6 –TeO 2 ceramics as a candidate for use as low-temperature co-fired ceramics (LTCC). We investigated microwave dielectric properties and low-temperature sintering conditions for Al 2 TeO 6 –TeO 2 ceramics. The calcined Al 2 TeO 6 powders were sintered at 900 °C for 2–10 h with 30–50 wt% additive TeO 2 . X-ray powder diffraction patterns showed that the sintered samples were Al 2 TeO 6 –TeO 2 composite with no other phase. The apparent density was improved with the additive TeO 2 content of up to 45 wt%. The dielectric constant (ε r ) increased by adding TeO 2 content from 35 to 45 wt%, although the quality factor (Q · f) decreased. During sintering at 900 °C, the ε r of the Al 2 TeO 6 –TeO 2 decreased slightly, whereas the Q · f increased gradually. The observed microstructures showed that the longer sintering time makes fewer pores in Al 2 TeO 6 –TeO 2 ceramics. Sintering at 900 °C for a long time contributes to densification, but it simultaneously causes TeO 2 evaporation. To prevent TeO 2 evaporation, we investigated the effects of annealing at 750 °C after sintering at 900 °C. Apparent densities or ε r for the annealed samples were higher than those of the non-annealed samples. The Q · f improved with increasing annealing duration time, suggesting that sintering proceeded well during annealing with slower TeO 2 evaporation at 750 °C. The results show that annealing at 750 °C is effective to facilitate sintering and to control TeO 2 evaporation

  13. Distinguishing new science from calibration effects in the electron-volt neutron spectrometer VESUVIO at ISIS

    Science.gov (United States)

    Chatzidimitriou-Dreismann, C. A.; Gray, E. MacA.; Blach, T. P.

    2012-06-01

    The "standard" procedure for calibrating the Vesuvio eV neutron spectrometer at the ISIS neutron source, forming the basis for data analysis over at least the last decade, was recently documented in considerable detail by the instrument's scientists. Additionally, we recently derived analytic expressions of the sensitivity of recoil peak positions with respect to fight-path parameters and presented neutron-proton scattering results that together called into question the validity of the "standard" calibration. These investigations should contribute significantly to the assessment of the experimental results obtained with Vesuvio. Here we present new results of neutron-deuteron scattering from D2 in the backscattering angular range (θ>90°) which are accompanied by a striking energy increase that violates the Impulse Approximation, thus leading unequivocally the following dilemma: (A) either the "standard" calibration is correct and then the experimental results represent a novel quantum dynamical effect of D which stands in blatant contradiction of conventional theoretical expectations; (B) or the present "standard" calibration procedure is seriously deficient and leads to artificial outcomes. For Case (A), we allude to the topic of attosecond quantum dynamical phenomena and our recent neutron scattering experiments from H2 molecules. For Case (B), some suggestions as to how the "standard" calibration could be considerably improved are made.

  14. Neutron radiography

    International Nuclear Information System (INIS)

    Hrdlicka, Z.

    1977-01-01

    Neutron radiography is a radiographic method using a neutron beam of a defined geometry. The neutron source usually consists of a research reactor, a specialized neutron radiography reactor or the 252 Cf radioisotope source. There are two types of the neutron radiography display system, viz., a system producing neutron radiography images by a photographic process or a system allowing a visual display, eg., using a television monitor. The method can be used wherever X-ray radiography is used except applications in the radiography of humans. The neutron radiography unit at UJV uses the WWR-S reactor as the neutron source and both types of the above mentioned display system. (J.P.)

  15. Molecular beam epitaxy of iodine-doped CdTe and (CdMg)Te

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, F.; Waag, A.; Litz, Th.; Scholl, S.; Schmitt, M.; Landwehr, G. (Physikalisches Inst. der Univ. Wuerzburg (Germany)); Bilger, G. (Zentrum fuer Sonnenenergie und Wasserstofforschung, Stuttgart (Germany))

    1994-08-01

    The n-type doping of CdTe and (CdMg)Te by the use of the solid dopant source material ZnI[sub 2] is reported. Doping levels as high as 7x10[sup 18] cm[sup -3] have been obtained in CdTe with carrier mobilities around 500 cm[sup 2]/V[center dot]s at room temperature. For a dopant incorporation higher than 1x10[sup 19] cm[sup -3] the free carrier concentration decreases, indicating the onset of a compensation mechanism, which is observed in the case of chlorine and bromine doping, too. Preliminary experiments show that with increasing Mg concentration the free carrier concentration decreases. Nevertheless, CdMgTe with a magnesium concentration x=0.37 (band gap 2.2 eV at room temperature) can be doped up to 2x10[sup 17] cm[sup -3]. The existence of deep donor levels in this CdTe based ternary is not supposed to be the only reason for the reduction of the free carrier concentration. For high Mg support during molecular beam epitaxial (MBE) growth of wide gap (CdMg)Te layers, the ZnI[sub 2] incorporation is reduced, leading to low doping levels, too

  16. Determination of K shell fluorescence cross-section and Kβ/Kα intensity ratios for Fe, Se, Te, FeSe, FeTe and TeSe

    International Nuclear Information System (INIS)

    Saydam, M.; Aksoy, C.; Cengiz, E.; Alaşalvar, C.; Tıraşoğlu, E.; Apaydın, G.

    2012-01-01

    The fluorescence cross-sections (σ Ki ) and the intensity ratios K β /K α for pure Fe, Se, Te elements and FeSe, FeTe, TeSe complexes have been investigated. The samples were excited by 59.5 keV γ-rays from 241 Am annular radioactive source and emitted X-rays. They were counted by an Ultra-LEGe detector with resolution of 150 eV at 5.9 keV. For pure elements results have been compared with the theoretical calculated values. According to our results band length and mutual interaction of atoms affected the results. We claimed that these effects would help researchers who study on superconductors, especially determining which compound can be show the superconductor properties. - Highlights: ► TeSe, FeSe and FeTe complexes have affected each other in terms of charge transfer. ► Fe excitement and enhancement have been made by Se and Te. ► Attractive interactions between electrons can help to becoming superconductivity.

  17. Neutron matter, neutron pairing, and neutron drops based on chiral effective field theory interactions

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, Thomas

    2016-10-19

    The physics of neutron-rich systems is of great interest in nuclear and astrophysics. Precise knowledge of the properties of neutron-rich nuclei is crucial for understanding the synthesis of heavy elements. Infinite neutron matter determines properties of neutron stars, a final stage of heavy stars after a core-collapse supernova. It also provides a unique theoretical laboratory for nuclear forces. Strong interactions are determined by quantum chromodynamics (QCD). However, QCD is non-perturbative at low energies and one presently cannot directly calculate nuclear forces from it. Chiral effective field theory circumvents these problems and connects the symmetries of QCD to nuclear interactions. It naturally and systematically includes many-nucleon forces and gives access to uncertainty estimates. We use chiral interactions throughout all calculation in this thesis. Neutron stars are very extreme objects. The densities in their interior greatly exceed those in nuclei. The exact composition and properties of neutron stars is still unclear but they consist mainly of neutrons. One can explore neutron stars theoretically with calculations of neutron matter. In the inner core of neutron stars exist very high densities and thus maybe exotic phases of matter. To investigate whether there exists a phase transition to such phases even at moderate densities we study the chiral condensate in neutron matter, the order parameter of chiral symmetry breaking, and find no evidence for a phase transition at nuclear densities. We also calculate the more extreme system of spin-polarised neutron matter. With this we address the question whether there exists such a polarised phase in neutron stars and also provide a benchmark system for lattice QCD. We find spin-polarised neutron matter to be an almost non-interacting Fermi gas. To understand the cooling of neutron stars neutron pairing is of great importance. Due to the high densities especially triplet pairing is of interest. We

  18. O papel da biblioteca universitária na inclusão de alunos com deficiência no ensino superior

    Directory of Open Access Journals (Sweden)

    Eliane Maria Stroparo

    2016-02-01

    Full Text Available DOI: http://dx.doi.org/10.5902/1984644417430O artigo apresenta reflexões sobre a educação como um direito de todos, tendo como recorte específico o papel das bibliotecas universitárias na inclusão dos alunos com deficiência no ensino superior. Como objetivo visa analisar e discutir a educação inclusiva no ensino superior procurando compreender os processos pelos quais se articula com as bibliotecas universitárias. A pesquisa se desenvolveu através de referencial teórico com enfoque descritivo. A coleta de dados foi efetuada por meio de observações em 10 bibliotecas, entrevistas semiestruturadas com os respectivos gestores de bibliotecas e com 17 alunos com deficiência matriculados na Universidade Federal do Paraná (UFPR. Destaca a acessibilidade no Sistema de Bibliotecas (SiBi da UFPR e a inclusão de alunos com deficiência, evidenciando-se a necessidade da implantação de política institucional inclusiva para erradicação de barreiras e favorecimento no acesso e permanência com sucesso de alunos com deficiência no ensino superior.

  19. The Los Alamos Neutron Science Center Spallation Neutron Sources

    International Nuclear Information System (INIS)

    Nowicki, Suzanne F.; Wender, Stephen A.; Mocko, Michael

    2017-01-01

    The Los Alamos Neutron Science Center (LANSCE) provides the scientific community with intense sources of neutrons, which can be used to perform experiments supporting civilian and national security research. These measurements include nuclear physics experiments for the defense program, basic science, and the radiation effect programs. This paper focuses on the radiation effects program, which involves mostly accelerated testing of semiconductor parts. When cosmic rays strike the earth's atmosphere, they cause nuclear reactions with elements in the air and produce a wide range of energetic particles. Because neutrons are uncharged, they can reach aircraft altitudes and sea level. These neutrons are thought to be the most important threat to semiconductor devices and integrated circuits. The best way to determine the failure rate due to these neutrons is to measure the failure rate in a neutron source that has the same spectrum as those produced by cosmic rays. Los Alamos has a high-energy and a low-energy neutron source for semiconductor testing. Both are driven by the 800-MeV proton beam from the LANSCE accelerator. The high-energy neutron source at the Weapons Neutron Research (WNR) facility uses a bare target that is designed to produce fast neutrons with energies from 100 keV to almost 800 MeV. The measured neutron energy distribution from WNR is very similar to that of the cosmic-ray-induced neutrons in the atmosphere. However, the flux provided at the WNR facility is typically 5×107 times more intense than the flux of the cosmic-ray-induced neutrons. This intense neutron flux allows testing at greatly accelerated rates. An irradiation test of less than an hour is equivalent to many years of neutron exposure due to cosmic-ray neutrons. The low-energy neutron source is located at the Lujan Neutron Scattering Center. It is based on a moderated source that provides useful neutrons from subthermal energies to ~100 keV. The characteristics of these sources

  20. The Los Alamos Neutron Science Center Spallation Neutron Sources

    Science.gov (United States)

    Nowicki, Suzanne F.; Wender, Stephen A.; Mocko, Michael

    The Los Alamos Neutron Science Center (LANSCE) provides the scientific community with intense sources of neutrons, which can be used to perform experiments supporting civilian and national security research. These measurements include nuclear physics experiments for the defense program, basic science, and the radiation effect programs. This paper focuses on the radiation effects program, which involves mostly accelerated testing of semiconductor parts. When cosmic rays strike the earth's atmosphere, they cause nuclear reactions with elements in the air and produce a wide range of energetic particles. Because neutrons are uncharged, they can reach aircraft altitudes and sea level. These neutrons are thought to be the most important threat to semiconductor devices and integrated circuits. The best way to determine the failure rate due to these neutrons is to measure the failure rate in a neutron source that has the same spectrum as those produced by cosmic rays. Los Alamos has a high-energy and a low-energy neutron source for semiconductor testing. Both are driven by the 800-MeV proton beam from the LANSCE accelerator. The high-energy neutron source at the Weapons Neutron Research (WNR) facility uses a bare target that is designed to produce fast neutrons with energies from 100 keV to almost 800 MeV. The measured neutron energy distribution from WNR is very similar to that of the cosmic-ray-induced neutrons in the atmosphere. However, the flux provided at the WNR facility is typically 5×107 times more intense than the flux of the cosmic-ray-induced neutrons. This intense neutron flux allows testing at greatly accelerated rates. An irradiation test of less than an hour is equivalent to many years of neutron exposure due to cosmic-ray neutrons. The low-energy neutron source is located at the Lujan Neutron Scattering Center. It is based on a moderated source that provides useful neutrons from subthermal energies to ∼100 keV. The characteristics of these sources, and

  1. Fabrication of Te and Te-Au Nanowires-Based Carbon Fiber Fabrics for Antibacterial Applications

    Directory of Open Access Journals (Sweden)

    Ting-Mao Chou

    2016-02-01

    Full Text Available Pathogenic bacteria that give rise to diseases every year remain a major health concern. In recent years, tellurium-based nanomaterials have been approved as new and efficient antibacterial agents. In this paper, we developed the approach to directly grow tellurium nanowires (Te NWs onto commercial carbon fiber fabrics and demonstrated their antibacterial activity. Those Te NWs can serve as templates and reducing agents for gold nanoparticles (Au NPs to deposit. Three different Te-Au NWs with varied concentration of Au NPs were synthesized and showed superior antibacterial activity and biocompability. These results indicate that the as-prepared carbon fiber fabrics with Te and Te-Au NWs can become antimicrobial clothing products in the near future.

  2. Delineation of phase fields at the Te-rich end of the Ru Te binary system

    Science.gov (United States)

    Ali (Basu), M.; Bharadwaj, S. R.; Das, D.

    2005-04-01

    The tellurium rich side of the ruthenium-tellurium binary system was studied by differential thermal analysis. To avoid reported problems of Te loss by evaporation and reactive interference of Te to the thermocouples of the thermal analyzer, the present study made use of specially designed sealed quartz capsules as DTA containers. The thermal analyses were carried out over the compositional range of 0.66 ⩽ xTe ⩽ 1.00 with the help of SETARAM TG/DTA and other indigenously built thermal analyzers available in this laboratory. The thermal data generated for fifteen different compositions were interpreted for the nature of phase transitions occurring at their characteristic temperatures. The Ru-Te binary system was found to have a eutectic transformation at 444 °C at a composition of xTe = 0.918 and a monotectic transformation at 447 °C at a composition of xTe = 0.700. Up to 6 at.% Ru is soluble in Te at about 440 °C.

  3. Delineation of phase fields at the Te-rich end of the Ru-Te binary system

    International Nuclear Information System (INIS)

    Ali, M.; Bharadwaj, S.R.; Das, D.

    2005-01-01

    The tellurium rich side of the ruthenium-tellurium binary system was studied by differential thermal analysis. To avoid reported problems of Te loss by evaporation and reactive interference of Te to the thermocouples of the thermal analyzer, the present study made use of specially designed sealed quartz capsules as DTA containers. The thermal analyses were carried out over the compositional range of 0.66 x Te 1.00 with the help of SETARAM TG/DTA and other indigenously built thermal analyzers available in this laboratory. The thermal data generated for fifteen different compositions were interpreted for the nature of phase transitions occurring at their characteristic temperatures. The Ru-Te binary system was found to have a eutectic transformation at 444 deg. C at a composition of x Te = 0.918 and a monotectic transformation at 447 deg. C at a composition of x Te = 0.700. Up to 6 at.% Ru is soluble in Te at about 440 deg. C

  4. Workshop on polarized neutron filters and polarized pulsed neutron experiments

    International Nuclear Information System (INIS)

    Itoh, Shinichi

    2004-07-01

    The workshop was held in KEK by thirty-three participants on April 26, 2004. The polarized neutron filter method was only discussed. It consists of three parts; the first part was discussed on the polarized neutron methods, the second part on the polarized neutron experiments and the third on the pulse neutron spectrometer and polarized neutron experiments. The six papers were presented such as the polarized 3 He neutron spin filter, neutron polarization by proton polarized filter, soft master and neutron scattering, polarized neutron in solid physics, polarization experiments by chopper spectroscope and neutron polarization system in superHRPD. (S.Y.)

  5. Neutron matter, symmetry energy and neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Stefano, Gandolfi [Los Alamos National Laboratory (LANL); Steiner, Andrew W [ORNL

    2016-01-01

    Recent progress in quantum Monte Carlo with modern nucleon-nucleon interactions have enabled the successful description of properties of light nuclei and neutron-rich matter. Of particular interest is the nuclear symmetry energy, the energy cost of creating an isospin asymmetry, and its connection to the structure of neutron stars. Combining these advances with recent observations of neutron star masses and radii gives insight into the equation of state of neutron-rich matter near and above the saturation density. In particular, neutron star radius measurements constrain the derivative of the symmetry energy.

  6. Fail-safe neutron shutter used for thermal neutron radiography

    International Nuclear Information System (INIS)

    Sachs, R.D.; Morris, R.A.

    1976-11-01

    A fail-safe, reliable, easy-to-use neutron shutter was designed, built, and put into operation at the Omega West Reactor, Los Alamos Scientific Laboratory. The neutron shutter will be used primarily to perform thermal neutron radiography, but is also available for a highly collimated source of thermal neutrons [neutron flux = 3.876 x 10 6 (neutrons)/(cm 2 .s)]. Neutron collimator sizes of either 10.16 by 10.16 cm or 10.16 by 30.48 cm are available

  7. Superstrengthening Bi2Te3 through Nanotwinning

    Science.gov (United States)

    Li, Guodong; Aydemir, Umut; Morozov, Sergey I.; Wood, Max; An, Qi; Zhai, Pengcheng; Zhang, Qingjie; Goddard, William A.; Snyder, G. Jeffrey

    2017-08-01

    Bismuth telluride (Bi2Te3 ) based thermoelectric (TE) materials have been commercialized successfully as solid-state power generators, but their low mechanical strength suggests that these materials may not be reliable for long-term use in TE devices. Here we use density functional theory to show that the ideal shear strength of Bi2Te3 can be significantly enhanced up to 215% by imposing nanoscale twins. We reveal that the origin of the low strength in single crystalline Bi2Te3 is the weak van der Waals interaction between the Te1 coupling two Te 1 - Bi - Te 2 - Bi - Te 1 five-layer quint substructures. However, we demonstrate here a surprising result that forming twin boundaries between the Te1 atoms of adjacent quints greatly strengthens the interaction between them, leading to a tripling of the ideal shear strength in nanotwinned Bi2Te3 (0.6 GPa) compared to that in the single crystalline material (0.19 GPa). This grain boundary engineering strategy opens a new pathway for designing robust Bi2Te3 TE semiconductors for high-performance TE devices.

  8. LIBRA-LiTE: A commercial size light ion fusion power plant

    International Nuclear Information System (INIS)

    Badger, B.; Choi, B.; Engelstad, R.L.; Kulcinski, G.L.; Lovell, E.G.; MacFarlane, J.J.; Mogehed, E.A.; Moses, G.A.; Peterson, R.R.; Rutledge, S.; Sawan, M.E.; Sviatoslavsky, G.; Sviatoslavsky, I.N.; Wittenberg, L.J.

    1992-05-01

    LIBRA-LiTE is a concept study for future 1000 MWe nuclear fusion reactors operating on the principle of inertial confinement. Light ions, e.g. lithium ions, are given an energy of 25-35 MeV in an accelerator and focused symmetrically onto a target (deuterium-tritium filled sphere of 7 mm diameter) in a reactor chamber. The fusion reaction is ignited by shock wave induced compression of the target. The radiation (photons, neutrons, ions) is absorbed in a blanket where the thermal power is removed by a coolant and tritium is rebred. The LIBRA-LiTE concept study is the continuation of the earlier LIBRA study (330 MWe) with a modified concept of light ion beam focusing. Starting from an ion source (diode), the lithium ion beams are focused ballistically onto the target. For this to be achieved, lithium must be used as the coolant in the reactor chamber and the blanket concept must be slightly modified by providing steel tubes (HT-9) as guiding tubes for the coolant flow. A particular engineering problem to be solved are the ion beam focusing magnets, which have to extend rather closely up to the center of the reactor chamber. (orig.) [de

  9. Electronic structure of Fe1.08Te bulk crystals and epitaxial FeTe thin films on Bi2Te3

    Science.gov (United States)

    Arnold, Fabian; Warmuth, Jonas; Michiardi, Matteo; Fikáček, Jan; Bianchi, Marco; Hu, Jin; Mao, Zhiqiang; Miwa, Jill; Singh, Udai Raj; Bremholm, Martin; Wiesendanger, Roland; Honolka, Jan; Wehling, Tim; Wiebe, Jens; Hofmann, Philip

    2018-02-01

    The electronic structure of thin films of FeTe grown on Bi2Te3 is investigated using angle-resolved photoemission spectroscopy, scanning tunneling microscopy and first principles calculations. As a comparison, data from cleaved bulk Fe1.08Te taken under the same experimental conditions is also presented. Due to the substrate and thin film symmetry, FeTe thin films grow on Bi2Te3 in three domains, rotated by 0°, 120°, and 240°. This results in a superposition of photoemission intensity from the domains, complicating the analysis. However, by combining bulk and thin film data, it is possible to partly disentangle the contributions from three domains. We find a close similarity between thin film and bulk electronic structure and an overall good agreement with first principles calculations, assuming a p-doping shift of 65 meV for the bulk and a renormalization factor of around two. By tracking the change of substrate electronic structure upon film growth, we find indications of an electron transfer from the FeTe film to the substrate. No significant change of the film’s electronic structure or doping is observed when alkali atoms are dosed onto the surface. This is ascribed to the film’s high density of states at the Fermi energy. This behavior is also supported by the ab initio calculations.

  10. High performance p-i-n CdTe and CdZnTe detectors

    CERN Document Server

    Khusainov, A K; Ilves, A G; Morozov, V F; Pustovoit, A K; Arlt, R D

    1999-01-01

    A breakthrough in the performance of p-i-n CdTe and CdZnTe detectors is reported. The detector stability has been significantly improved, allowing their use in precise gamma and XRF applications. Detectors with energy resolution close to Si and Ge were produced operating with only -30--35 deg. C cooling (by a Peltier cooler of 15x15x10 mm size and a consumed power less than 5 W). Presently detectors with volume of up to 300 mm sup 3 are available. In terms of photoelectric effect efficiency it corresponds to HPGe detectors with volumes of about 1.5 cm sup 3. The possibilities of further improvement of CdTe and CdZnTe detector characteristics are discussed in this paper.

  11. Extraction of the neutron-neutron scattering length ann from kinematically complete neutron-deuteron breakup experiments

    International Nuclear Information System (INIS)

    Witala, H.; Hueber, D.; Gloeckle, W.; Tornow, W.; Gonzalez Trotter, D.E.

    1996-01-01

    Data for the neutron-neutron final-state-interaction cross section obtained recently in a kinematically complete neutron-deuteron breakup experiment have been reanalyzed using rigorous solutions of the three-nucleon Faddeev equations with realistic nucleon-nucleon interactions. A discrepancy was found with respect to a recent analysis based on the W-matrix approximation to the Paris potential. We also estimate theoretical uncertainties in extracting the neutron-neutron scattering length resulting from the use of different nucleon-nucleon interactions and the possible action of the two pion-exchange three-nucleon force. We find that there exists a certain production angle for the interacting neutron-neutron pair where the uncertainties become minimal. (author)

  12. Neutron Absorbing Ability Variation in Neutron Absorbing Material Caused by the Neutron Irradiation in Spent Fuel Storage Facility

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Hee Dong; Han, Seul Gi; Lee, Sang Dong; Kim, Ki Hong; Ryu, Eag Hyang; Park, Hwa Gyu [Doosan Heavy Industries and Construction, Changwon (Korea, Republic of)

    2014-10-15

    In spent fuel storage facility like high density spent fuel storage racks and dry storage casks, spent fuels are stored with neutron absorbing materials installed as a part of those facilities, and they are used for absorbing neutrons emitted from spent fuels. Usually structural material with neutron absorbing material of racks and casks are located around spent fuels, so it is irradiated by neutrons for long time. Neutron absorbing ability could be changed by the variation of nuclide composition in neutron absorbing material caused by the irradiation of neutrons. So, neutron absorbing materials are continuously faced with spent fuels with boric acid solution or inert gas environment. Major nuclides in neutron absorbing material are Al{sup 27}, C{sup 12}, B{sup 11}, B{sup 10} and they are changed to numerous other ones as radioactive decay or neutron absorption reaction. The B{sup 10} content in neutron absorbing material dominates the neutron absorbing ability, so, the variation of nuclide composition including the decrease of B{sup 10} content is the critical factor on neutron absorbing ability. In this study, neutron flux in spent fuel, the activation of neutron absorbing material and the variation of nuclide composition are calculated. And, the minimum neutron flux causing the decrease of B{sup 10} content is calculated in spent fuel storage facility. Finally, the variation of neutron multiplication factor is identified according to the one of B{sup 10} content in neutron absorbing material. The minimum neutron flux to impact the neutron absorbing ability is 10{sup 10} order, however, usual neutron flux from spent fuel is 10{sup 8} order. Therefore, even though neutron absorbing material is irradiated for over 40 years, B{sup 10} content is little decreased, so, initial neutron absorbing ability could be kept continuously.

  13. Application of GaAs and CdTe photoconductor detectors to x-ray flash radiography

    International Nuclear Information System (INIS)

    Mathy, F.; Cuzin, M.; Gagelin, J.J.; Mermet, R.; Piaget, B.; Rustique, J.; Verger, L.

    1991-01-01

    Semi-insulating GaAs and CdTe:Cl photoconductor probes were qualified on high energy X ray single shot flash generators. The estimated minimum detected dose per flash corresponding to a 230 mrad direct beam attenuated by 200 mm lead was 20 μrad. The dynamic range was about 4 decades in amplitude or charges, with a good linearity. Such detectors, by locating the origin of the parasitic scattered beam, could be used to eliminate this parasitic beam in X ray flash radiography in detonics experiments. Imaging possibilities are mentioned, as well as X ray generator monitoring with such detectors or with neutron preirradiated photoconductors

  14. Application of GaAs and CdTe photoconductor detectors to X-ray flash radiography

    International Nuclear Information System (INIS)

    Mathy, F.; Cuzin, M.; Gagelin, J.J.; Mermet, R.; Piaget, B.; Rustique, J.; Verger, L.; Hauducoeur, A.; Nicolas, P.; Le Dain, L.; Hyvernage, M.

    1992-01-01

    Some insulating GaAs and CdTe:Cl photoconductor probes were qualified on high energy X-ray single-shot flash generators. The estimated minimum detected dose per flash corresponding to a 230 mrad direct beam attenuated by 200 mm lead was 20 μrad. The dynamic range was about 4 decades in amplitude or charge, with a good linearity. Such detectors, by locating the origin of the parasitic scattered beam, could be used to eliminate this parasitic beam in X-ray flash radiography in detonics experiments. Imaging possibilities are mentioned, as well as X-ray generator monitoring with such detectors or with neutron preirradiated photoconductors. (orig.)

  15. Application of GaAs and CdTe photoconductor detectors to X-ray flash radiography

    Energy Technology Data Exchange (ETDEWEB)

    Mathy, F.; Cuzin, M.; Gagelin, J.J.; Mermet, R.; Piaget, B.; Rustique, J.; Verger, L. (CEA, Direction des Technologies Avancees, Lab. d' Electronique, de Technologie et d' Instrumentation, DSYS, 38 - Grenoble (France)); Hauducoeur, A.; Nicolas, P.; Le Dain, L.; Hyvernage, M. (CEA, Direction des Applications Militaires, 77 - Courtry (France))

    1992-11-15

    Some insulating GaAs and CdTe:Cl photoconductor probes were qualified on high energy X-ray single-shot flash generators. The estimated minimum detected dose per flash corresponding to a 230 mrad direct beam attenuated by 200 mm lead was 20 [mu]rad. The dynamic range was about 4 decades in amplitude or charge, with a good linearity. Such detectors, by locating the origin of the parasitic scattered beam, could be used to eliminate this parasitic beam in X-ray flash radiography in detonics experiments. Imaging possibilities are mentioned, as well as X-ray generator monitoring with such detectors or with neutron preirradiated photoconductors. (orig.).

  16. Application of GaAs and CdTe photoconductor detectors to x-ray flash radiography

    Energy Technology Data Exchange (ETDEWEB)

    Mathy, F.; Cuzin, M.; Gagelin, J.J.; Mermet, R.; Piaget, B.; Rustique, J.; Verger, L. [CEA Centre d`Etudes de Grenoble, 38 (FR). Direction des Technologies Avancees; Hauducoeur, A.; Nicolas, P.; Le Dain, L.; Hyvernage, M. [CEA Centre d`Etudes de Vaujours, 77 - Courtry (FR)

    1991-12-31

    Semi-insulating GaAs and CdTe:Cl photoconductor probes were qualified on high energy X ray single shot flash generators. The estimated minimum detected dose per flash corresponding to a 230 mrad direct beam attenuated by 200 mm lead was 20 {mu}rad. The dynamic range was about 4 decades in amplitude or charges, with a good linearity. Such detectors, by locating the origin of the parasitic scattered beam, could be used to eliminate this parasitic beam in X ray flash radiography in detonics experiments. Imaging possibilities are mentioned, as well as X ray generator monitoring with such detectors or with neutron preirradiated photoconductors.

  17. Investigation of primary cooling water chemistry following the partial meltdown of Pu-Be neutron source in Tehran Research Reactor Core (TRR)

    Energy Technology Data Exchange (ETDEWEB)

    Aghoyeh, Reza Gholizadeh [School of Research and Development of Nuclear Reactors and Accelerators, Nuclear Science and Technology Research Institute (NSTRI), Atomic Energy Organization of Iran (AEOI), P.O. Box: 14155-1339, Tehran (Iran, Islamic Republic of); Khalafi, Hossein, E-mail: hkhalafi@aeoi.org.i [School of Research and Development of Nuclear Reactors and Accelerators, Nuclear Science and Technology Research Institute (NSTRI), Atomic Energy Organization of Iran (AEOI), P.O. Box: 14155-1339, Tehran (Iran, Islamic Republic of)

    2011-03-15

    Research highlights: Effect of Pu-Be neutron source meltdown in core on reactor water chemistry. Water chemistry of primary cooling before, during and after of above incident was compared. Training importance. Management of nuclear incident and accident. - Abstract: Effect of Pu-Be neutron source meltdown in core on reactor water chemistry was main aim of this study. Leaving the neutron source in the core after reactor power exceeds a few hundred Watts was the main reason for its partial meltdown. Water chemistry of primary cooling before, during and after of above incident was compared. Activity of some radio-nuclides such as Ba-140, La-140, I-131, I-132, Te-132 and Xe-135 increased. Other radio-nuclides such as Nd-147, Xe-133, Sr-91, I-133 and I-135 are also detected which were not existed before this incident.

  18. Neutron optics using transverse field neutron spin echo method

    International Nuclear Information System (INIS)

    Achiwa, Norio; Hino, Masahiro; Yamauchi, Yoshihiro; Takakura, Hiroyuki; Tasaki, Seiji; Akiyoshi, Tsunekazu; Ebisawa, Toru.

    1993-01-01

    A neutron spin echo (NSE) spectrometer with perpendicular magnetic field to the neutron scattering plane, using an iron yoke type electro-magnet has been developed. A combination of cold neutron guider, supermirror neutron polarizer of double reflection type and supermirror neutron analyser was adopted for the spectrometer. The first application of the NSE spectrometer to neutron optics by passing Larmor precessing neutrons through gas, solid and liquid materials of several different lengths which are inserted in one of the precession field have been examined. Preliminary NSE spectra of this sample geometry are discussed. (author)

  19. X-ray electron spectra of chalcogenide glasses and polycrystalline alloys of Ge-Te and As-Te systems

    International Nuclear Information System (INIS)

    Panus, V.R.

    1990-01-01

    Comparative investigation into structures of crystals and glasses in Ge-Te and As-Te two-component systems was conducted. Analysis of x-ray electron spectra of Ge-Te and As-Te systems indicates, that processes of dissociation-association resulting in formation of new structure units occur in telluride melts at synthesis temperatures. Structural chemical composition of binary glass-like alloys of Ge-Te and As-Te systems differs essentially from the one that corresponds to fusibility equilibrium curve. Oxygen doping into tellurium-base glasses results mainly in occurence of structures forecasted due to thermochemical calculation

  20. Neutron radiography

    International Nuclear Information System (INIS)

    Hiraoka, Eiichi

    1988-01-01

    The thermal neutron absorption coefficient is essentially different from the X-ray absorption coefficient. Each substance has a characteristic absorption coefficient regardless of its density. Neutron deams have the following features: (1) neutrons are not transmitted efficiently by low molecular weight substances, (2) they are transmitted efficiently by heavy metals, and (3) the transmittance differs among isotopes. Thus, neutron beams are suitable for cheking for foreign matters in heavy metals and testing of composites consisting of both heavy and light materials. A neutron source generates fast neutrons, which should be converted into thermal neutrons by reducing their energy. Major neutron souces include nuclear reactors, radioisotopes and particle accelerators. Photographic films and television systems are mainly used to observe neutron transmission images. Computers are employed for image processing, computerized tomography and three-dimensional analysis. The major applications of neutron radiography include inspection of neclear fuel; evaluation of material for airplane; observation of fuel in the engine and oil in the hydraulic systems in airplanes; testing of composite materials; etc. (Nogami, K.)

  1. Neutron Dosimetry

    International Nuclear Information System (INIS)

    Vanhavere, F.

    2001-01-01

    The objective of SCK-CEN's R and D programme on neutron dosimetry is to improve the determination of neutron doses by studying neutron spectra, neutron dosemeters and shielding adaptations. In 2000, R and D focused on the contiued investigation of the bubble detectors type BD-PND and BDT, in particular their sensitivity and temperature dependence; the updating of SCK-CEN's criticality dosemeter, the investigation of the characteristics of new thermoluminescent materials and their use in neutron dosemetry; and the investigation of neutron shielding

  2. Electric transport properties of the pentatelluride materials HfTe{sub 5} and ZrTe{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Tritt, T M; Wilson, M L; Littleton, R L [and others

    1997-07-01

    The authors have measured the resistivity and thermopower of single crystals as well as polycrystalline pressed powders of the low-dimensional pentatelluride materials: HfTe{sub 5} and ZrTe{sub 5}. They have performed these measurements as a function of temperature between 5K and 320K. In the single crystals there is a peak in the resistivity for both materials at a peak temperature, T{sub p} where T{sub p} {approx} 80K for HfTe{sub 5} and T{sub p} {approx} 145K for ZrTe{sub 5}. Both materials exhibit a large p-type thermopower around room temperature which undergoes a change to n-type below the peak. These data are similar to behavior observed previously in these materials. They have also synthesized pressed powders of polycrystalline pentatelluride materials, HfTe{sub 5} and ZrTe{sub 5}. They have measured the resistivity and thermopower of these polycrystalline materials as a function of temperature between 5K and 320K. For the polycrystalline material, the room temperature thermopower for each of these materials is relatively high, +95 {micro}V/K and +65 {micro}V/K for HfTe{sub 5} and ZrTe{sub 5}, respectively. These values compare closely to thermopower values for single crystals of these materials. At 77 K, the thermopower is +55 {micro}V/K for HfTe{sub 5} and +35 {micro}V/K for ZrTe{sub 5}. In fact, the thermopower for the polycrystals decreases monotonically with temperature to T {approx} 5K, thus exhibiting p-type behavior over the entire range of temperature. As expected, the resistivity for the polycrystals is higher than the single crystal material, with values of 430 m{Omega}-cm and 24 m{Omega}-cm for HfTe{sub 5} and ZrTe{sub 5} respectively, compared to single crystal values of 0.35 m{Omega}-cm (HfTe{sub 5}) and 1.0 m{Omega}-cm (ZrTe{sub 5}). The authors have found that the peak in the resistivity evident in both single crystal materials is absent in these polycrystalline materials. They will discuss these materials in relation to their potential as

  3. Trace element analysis of human blood serum by neutron activation analysis

    International Nuclear Information System (INIS)

    Nakahara, H.; Nagame, Y.; Yoshizawa, Y.; Oda, H.; Gotoh, S.; Murakami, Y.

    1979-01-01

    An attempt was made to determine if there is any correlation between trace element concentrations in human blood serum and some specific diseases. The serum samples of the patients suffering from cancer, Down syndrome, and Banti syndrome were analyzed by the neutron activation method and compared with the trace element concentrations observed among clinically healthy men. The cancer patients had concentrations in Rb, Mn, Fe, Co, Cu, Zn, Al and Se below normal. The Down syndrome patients were found to have similar deficiencies in Cr, Mn, Fe, Co, Zn, Cu and Sb. (author)

  4. Contribuições a um pensar sociológico sobre a deficiência

    Directory of Open Access Journals (Sweden)

    Gustavo Martins Piccolo

    2013-06-01

    Full Text Available O artigo, erigido mediante processo de revisão literária, objetiva apresentar as contribuições do grupo londrino denominado Disability Studies, arcabouço teórico pouco conhecido em terras brasileiras e cujos textos possibilitam uma transformação nuclear na maneira de interpretar a deficiência, ao abordá-la como produto da insensibilidade da sociedade capitalista em incorporar as diferenças nas suas mais distintas esferas, portanto, obra de complexa discriminação institucional para a qual a única resposta apropriada é a ação revolucionária sobre a estrutura que nos circunscreve.

  5. Neutron Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Vanhavere, F

    2001-04-01

    The objective of SCK-CEN's R and D programme on neutron dosimetry is to improve the determination of neutron doses by studying neutron spectra, neutron dosemeters and shielding adaptations. In 2000, R and D focused on the contiued investigation of the bubble detectors type BD-PND and BDT, in particular their sensitivity and temperature dependence; the updating of SCK-CEN's criticality dosemeter, the investigation of the characteristics of new thermoluminescent materials and their use in neutron dosemetry; and the investigation of neutron shielding.

  6. Manufacturing Te/PEDOT Films for Thermoelectric Applications.

    Science.gov (United States)

    Culebras, Mario; Igual-Muñoz, Ana María; Rodríguez-Fernández, Carlos; Gómez-Gómez, María Isabel; Gómez, Clara; Cantarero, Andrés

    2017-06-21

    In this work, flexible Te films have been synthesized by electrochemical deposition using PEDOT [poly(3,4-ethylenedioxythiophene)] nanofilms as working electrodes. The Te electrodeposition time was varied to find the best thermoelectric properties of the Te/PEDOT double layers. To show the high quality of the Te films grown on PEDOT, the samples were analyzed by Raman spectroscopy, showing the three Raman active modes of Te: E 1 , A 1 , and E 2 . The X-ray diffraction spectra also confirmed the presence of crystalline Te on top of the PEDOT films. The morphology of the Te/PEDOT films was studied using scanning electron microscopy, showing a homogeneous distribution of Te along the film. Also an atomic force microscope was used to analyze the quality of the Te surface. Finally, the electrical conductivity and the Seebeck coefficient of the Te/PEDOT films were measured as a function of the Te deposition time. The films showed an excellent thermoelectric behavior, giving a maximum power factor of about 320 ± 16 μW m -1 K -2 after 2.5 h of Te electrochemical deposition, a value larger than that reported for thin films of Te. Qualitative arguments to explain this behavior are given in the discussion.

  7. Preliminary study of CdTe and CdTe:Cu thin films nanostructures deposited by using DC magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Marwoto, Putut; Made, D. P. Ngurah; Sugianto [Departement of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Semarang, Gunungpati, Semarang 50229 Jawa Tengah (Indonesia); Wibowo, Edy; Astuti, Santi Yuli; Aryani, Nila Prasetya [Materials Research Group, Laboratory of Thin Film, Department of Physics, Universitas Negeri Semarang, Gunungpati, Semarang 50229 Jawa Tengah (Indonesia); Othaman, Zulkafli [Departement of Physics, Universiti Teknologi Malaysia (UTM), Skudai, Johor Bahru (Malaysia)

    2013-09-03

    Growth and properties of CdTe and CdTe:Cu thin films nanostrucures deposited by using dc magnetron sputtering are reported. Scanning electron microscope (SEM) was used to observe the surface morphologies of the thin films. At growth conditions of 250 °C and 14 W, CdTe films did not yet evenly deposited. However, at growth temperature and plasma power of 325 °C and 43 W, both CdTe and CdTe:Cu(2%) have deposited on the substrates. In this condition, the morphology of the films indicate that the films have a grain-like nanostructures. Grain size diameter of about 200 nm begin to appear on top of the films. Energy Dispersive X-rays spectroscopy (EDX) was used to investigate chemical elements of the Cu doped CdTe film deposited. It was found that the film deposited consist of Cd, Te and Cu elements. XRD was used to investigate the full width at half maximum (FWHM) values of the thin films deposited. The results show that CdTe:Cu(2%) thin film has better crystallographic properties than CdTe thin film. The UV-Vis spectrometer was used to investigate the optical properties of thin films deposited. The transmittance spectra showed that transmittance of CdTe:Cu(2%) film is lower than CdTe film. It was found that the bandgap energy of CdTe and CdTe:Cu(2%) thin films of about 1.48 eV.

  8. Super-light baryo-photons, weak gravity conjecture and exotic instantons in neutron-antineutron transitions

    Science.gov (United States)

    Addazi, Andrea

    2018-05-01

    In companion papers (A. Addazi, Nuovo Cim. C, 38(1): 21 (2015); A. Addazi, Z. Berezhiani, and Y. Kamyshkov, arXiv:1607.00348), we have discussed current bounds on a new super-light baryo-photon, associated with a U(1) B-L gauge, from current neutron-antineutron data, which are competitive with Eötvös-type experiments. Here, we discuss the implications of possible baryo-photon detection in string theory and quantum gravity. The discovery of a very light gauge boson should imply violation of the weak gravity conjecture, carrying deep consequences for our understanding of holography, quantum gravity and black holes. We also show how the detection of a baryo-photon would exclude the generation of all B–L violating operators from exotic stringy instantons. We will argue against the common statement in the literature that neutron-antineutron data may indirectly test at least the 300–1000 TeV scale. Searches for baryo-photons can provide indirect information on the Planck (or string) scale (quantum black holes, holography and non-perturbative stringy effects). This strongly motivates new neutron-antineutron experiments with adjustable magnetic fields dedicated to the detection of super-light baryo-photons.

  9. Neutronic analysis of JET external neutron monitor response

    Energy Technology Data Exchange (ETDEWEB)

    Snoj, Luka, E-mail: luka.snoj@ijs.si [Reactor Physics Division, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Lengar, Igor; Čufar, Aljaž [Reactor Physics Division, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Syme, Brian; Popovichev, Sergey [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, OX14 3DB, United Kingdom (United Kingdom); Batistoni, Paola [ENEA C. R. Frascati, via E. Fermi 45, 00044 Frascati, Roma (Italy); Conroy, Sean [VR Association, Uppsala University, Department of Physics and Astronomy, PO Box 516, SE-75120 Uppsala (Sweden)

    2016-11-01

    Highlights: • We model JET tokamak containing JET remote handling system. • We investigate effect of remote handling system on external neutron monitor response. • Remote handling system correction factors are calculated. • Integral correction factors are relatively small, i.e up to 8%. - Abstract: The power output of fusion devices is measured in terms of the neutron yield which relates directly to the fusion yield. JET made a transition from Carbon wall to ITER-Like Wall (Beryllium/Tungsten/Carbon) during 2010–11. Absolutely calibrated measurement of the neutron yield by JET neutron monitors was ensured by direct measurements using a calibrated {sup 252}Cf neutron source (NS) deployed by the in-vessel remote handling system (RHS) inside the JET vacuum vessel. Neutronic calculations were required in order to understand the neutron transport from the source in the vacuum vessel to the fission chamber detectors mounted outside the vessel on the transformer limbs of the tokamak. We developed a simplified computational model of JET and the JET RHS in Monte Carlo neutron transport code MCNP and analyzed the paths and structures through which neutrons reach the detectors and the effect of the JET RHS on the neutron monitor response. In addition we performed several sensitivity studies of the effect of substantial massive structures blocking the ports on the external neutron monitor response. As the simplified model provided a qualitative picture of the process only, some calculations were repeated using a more detailed full 3D model of the JET tokamak.

  10. Investigation of Response of Several Neutron Surveymeters by a DT Neutron Generator

    International Nuclear Information System (INIS)

    Kim, Sang In; Jang, In Su; Kim, Jang Lyul; Lee, Jung IL; Kim, Bong Hwan

    2012-01-01

    Several neutron measuring devices were tested under the neutron fields characterized with two distinct kinds of thermal and fast neutron spectrum. These neutron fields were constructed by the mixing of both thermal neutron fields and fast neutron fields. The thermal neutron field was constructed using by a graphite pile with eight AmBe neutron sources. The fast neutron field of 14 MeV was made by a DT neutron generator. In order to change the fraction of fast neutron fluence rate in each neutron fields, a neutron generator was placed in the thermal neutron field at 50 cm and 150 cm from the reference position. The polyethylene neutron collimator was used to make moderated 14 MeV neutron field. These neutron spectra were measured by using a Bonner sphere system with an LiI scintillator, and dosimetric quantities delivered to neutron surveymeters were determined from these measurement results.

  11. Surface preparation effects on efficient indium-tin-oxide-CdTe and CdS-CdTe heterojunction solar cells

    Science.gov (United States)

    Werthen, J. G.; Fahrenbruch, A. L.; Bube, R. H.; Zesch, J. C.

    1983-05-01

    The effects of CdTe surface preparation and subsequent junction formation have been investigated through characterization of ITO/CdTe and CdS/CdTe heterojunction solar cells formed by electron beam evaporation of indium-tin-oxide (ITO) and CdS onto single crystal p-type CdTe. Surfaces investigated include air-cleaved (110) surfaces, bromine-in-methanol etched (110) and (111) surfaces, and teh latter surfaces subjected to a hydrogen heat treatment. Both air-cleaved and hydrogen heat treated surfaces have a stoichiometric Cd to Te ratio. The ITO/CdTe junction formation process involves an air heat treatment, which ahs serious effects on the behavior of junctions formed on these surfaces. Etched surfaces which have a large excesss of Te, are less affected by the junction formation process and result in ITO/CdTe heterojunctions with solar efficiencies of 9% (Vsc =20 mA/cm2). Use of low-doped CdTe results in junctions characterized by considerably larger open-circuit votages (Voc =0.81 V) which are attributable to increasing diode factors caused by a shift from interfacial recombination to recombination in the depletion region. Resulting solar efficiencies reach 10.5% which is the highest value reported to date for a genuine CdTe heterojunction, CdS/CdTe heterojunctions show a strong dependence on CdTe surface condition, but less influence on the junction formation process. Solar efficiencies of 7.5% on an etched and heat treated surface are observed. All of these ITO/CdTe and CdS/CdTe heterojunctions have been stable for at least 10 months.

  12. Neutron Imaging at Compact Accelerator-Driven Neutron Sources in Japan

    Directory of Open Access Journals (Sweden)

    Yoshiaki Kiyanagi

    2018-03-01

    Full Text Available Neutron imaging has been recognized to be very useful to investigate inside of materials and products that cannot be seen by X-ray. New imaging methods using the pulsed structure of neutron sources based on accelerators has been developed also at compact accelerator-driven neutron sources and opened new application fields in neutron imaging. The world’s first dedicated imaging instrument at pulsed neutron sources was constructed at J-PARC in Japan owing to the development of such new methods. Then, usefulness of the compact accelerator-driven neutron sources in neutron science was recognized and such facilities were newly constructed in Japan. Now, existing and new sources have been used for neutron imaging. Traditional imaging and newly developed pulsed neutron imaging such as Bragg edge transmission have been applied to various fields by using compact and large neutron facilities. Here, compact accelerator-driven neutron sources used for imaging in Japan are introduced and some of their activities are presented.

  13. New developments in clinical applications of CdTe and CdZnTe detectors

    International Nuclear Information System (INIS)

    Scheiber, C.

    1996-01-01

    This review about the medical applications of CdTe and CdZnTe is an update on the 1992 paper (1992). This new paper is legitimized by the recent progress which has been made in this field. First of all, the usefulness of a new material, i.e. CdZnTe, has been demonstrated. While the two materials are still being improved, it seems as yet too early to debate which of CdTe:Cl or CdZnTe will be the best choice. Historical applications span over the past 18 years, involving devices like miniature probes for per-operative scintigraphy or the monitoring of physiological functions and, closer to us, appliances dedicated to bone densitometry, and have been expanding as such devices have become commercially available, for many years now. Newly available microelectronic circuitry allows 2D-arrays to be built for digital quantitative X-ray (chest, dental..) and for high-resolution gamma cameras. The clinical demand is very high, especially in the field of nuclear medicine. Although there already exist clinical demonstrators, the future of such CdTe applications depends on further reduction in material and device mounting costs. New perspectives concern XCT applications, but the data resulting from research work are kept for restricted use within industrial R and D laboratories. (orig.)

  14. Accelerator based neutron source for neutron capture therapy

    International Nuclear Information System (INIS)

    Salimov, R.; Bayanov, B.; Belchenko, Yu.; Belov, V.; Davydenko, V.; Donin, A.; Dranichnikov, A.; Ivanov, A.; Kandaurov, I; Kraynov, G.; Krivenko, A.; Kudryavtsev, A.; Kursanov, N.; Savkin, V.; Shirokov, V.; Sorokin, I.; Taskaev, S.; Tiunov, M.

    2004-01-01

    Full text: The Budker Institute of Nuclear Physics (Novosibirsk) and the Institute of Physics and Power Engineering (Obninsk) have proposed an accelerator based neutron source for neutron capture and fast neutron therapy for hospital. Innovative approach is based upon vacuum insulation tandem accelerator (VITA) and near threshold 7 Li(p,n) 7 Be neutron generation. Pilot accelerator based neutron source for neutron capture therapy is under construction now at the Budker Institute of Nuclear Physics, Novosibirsk, Russia. In the present report, the pilot facility design is presented and discussed. Design features of facility components are discussed. Results of experiments and simulations are presented. Complete experimental tests are planned by the end of the year 2005

  15. Formation of self assembled PbTe quantum dots in CdTe on Si(111)

    Science.gov (United States)

    Felder, F.; Fognini, A.; Rahim, M.; Fill, M.; Müller, E.; Zogg, H.

    2010-01-01

    We describe the growth and formation of self assembled PbTe quantum dots in a CdTe host on a silicon (111) substrate. Annealing yields different photoluminescence spectra depending on initial PbTe layer thickness, thickness of the CdTe cap layer and annealing temperature. Generally two distinct emission peaks at ˜0.3 eV and ˜0.45 eV are visible. Model calculations explaining their temperature dependence are performed. The dot size corresponds well with the estimated sizes from electron microscopy images. The quantum dots may be used as absorber within a mid-infrared detector.

  16. Studies of the nucleon-nucleus and the nucleon-nucleon interactions using polarized neutron beams

    International Nuclear Information System (INIS)

    Walter, R.L.; Howell, C.R.; Tornow, W.

    1988-01-01

    The results o four scattering measurements using beams of polarized neutrons are described. Results for the analyzing power A y (θ) for elastic scattering of neutrons from protons and deuterons are compared to calculations based on the Paris and the Bonn nucleon-nucleon interactions. Deficiencies particularly in the Bonn model are indicated. A nucleon-nucleus potential is derived from σ(θ) and A y (θ) data for n + 28 Si and p + 28 Si and the Coulomb correction terms are derived according to two approaches. A Fourier-Bessel expansion is used to investigate the form factors of the terms of the n + 208 Pb potential which are necessary to describe σ(θ) and A y (θ) data from 6 to 10 MeV. The nature of the spin-orbit term is also presented. (author)

  17. Operation of CdZnTe Semiconductor Detectors in Liquid Scintillator for the COBRA Experiment

    International Nuclear Information System (INIS)

    Oldorf, Christian

    2015-08-01

    COBRA, the Cadmium-Zinc-Telluride O-neutrino double-Beta Research Apparatus, is an experiment aiming for the measurement of the neutrinoless double beta decay with several isotopes, in particular 116 Cd, 106 Cd and 130 Te. A highly granular large scale experiment with about 400 kg of CdZnTe semiconductor detectors is currently under development. To provide evidence for the neutrinoless double beta decay of 116 Cd, a background rate in the order of 10 -3 counts/keV/kg/a is needed to achieve the required half-life sensitivity of at least 2 . 10 26 years. To reach this target, the detectors have to be operated in a highly pure environment, shielded from external radiation. Liquid scintillator is a promising candidate as a circum fluent replacement for the currently used lacquer. Next to the function as highly pure passivation material, liquid scintillator also acts as a neutron shield and active veto for external gammas. Within this thesis, the design, construction and assembly of a test set-up is described. The operation of four CdZnTe detectors after several years of storage in liquid scintillator is demonstrated. Next to extensive material compatibility tests prior to the assembly, the commissioning of the set-up and the characterization of the detectors are shown. Finally, results concerning the background reduction capability of liquid scintillator and the detection of cosmic muons are presented and compared to a Monte Carlo simulation.

  18. Comparative study of CdTe sources used for deposition of CdTe thin films by close spaced sublimation technique

    Directory of Open Access Journals (Sweden)

    Wagner Anacleto Pinheiro

    2006-03-01

    Full Text Available Unlike other thin film deposition techniques, close spaced sublimation (CSS requires a short source-substrate distance. The kind of source used in this technique strongly affects the control of the deposition parameters, especially the deposition rate. When depositing CdTe thin films by CSS, the most common CdTe sources are: single-crystal or polycrystalline wafers, powders, pellets or pieces, a thick CdTe film deposited onto glass or molybdenum substrate (CdTe source-plate and a sintered CdTe powder. In this work, CdTe thin films were deposited by CSS technique from different CdTe sources: particles, powder, compact powder, a paste made of CdTe and propylene glycol and source-plates (CdTe/Mo and CdTe/glass. The largest deposition rate was achieved when a paste made of CdTe and propylene glycol was used as the source. CdTe source-plates led to lower rates, probably due to the poor heat transmission, caused by the introduction of the plate substrate. The results also showed that compacting the powder the deposition rate increases due to the better thermal contact between powder particles.

  19. Design of hyper-thermal neutron irradiation fields for neutron capture therapy in KUR-heavy water neutron irradiation facility. Mounting of hyper-thermal neutron converter in therapeutic collimator

    International Nuclear Information System (INIS)

    Sakurai, Y.; Kobayashi, T.

    2001-01-01

    Neutron capture therapy (NCP) using thermal neutron needs to improve of depth dose distribution in a living body. Epi-thermal neutron following moderation of fast neutron is usually used for improving of the depth dose distribution. The moderation method of fast neutron, however, gets mixed some of high energy neutron which give some of serious effects to a living body, and involves the difficulty for collimation of thermal neutron to the diseased part. Hyper-thermal neutrons, which are in an energy range of 0.1-3 eV at high temperature side of thermal neutron, are under consideration for application to the NCP. The hyper-thermal neutrons can be produced by up-scattering of thermal neutron in a high temperature material. Fast neutron components in collimator for the NCP reduce on application of the up-scattering method. Graphite at high temperature (>1000k) is used as a hyper-thermal neutron converter. The hyper-thermal neutron converter is planted to mount on therapeutic collimator which is located at the nearest side of patient for the NCP. Total neutron flux, ratio of hyper-thermal neutron to total neutron, and ratio of gamma-ray dose to neutron flux are calculated as a function of thickness of the graphite converter using monte carlo code MCNP-V4B. (M. Suetake)

  20. The secondary neutron sources for generation of particular neutron fluxes

    International Nuclear Information System (INIS)

    Tracz, G.

    2007-07-01

    The foregoing paper presents the doctor's thesis entitled '' The secondary neutron sources for generation of particular neutron fluxes ''. Two secondary neutron sources have been designed, which exploit already existing primary sources emitting neutrons of energies different from the desired ones. The first source is devoted to boron-neutron capture therapy (BNCT). The research reactor MARIA at the Institute of Atomic Energy in Swierk (Poland) is the primary source of the reactor thermal neutrons, while the secondary source should supply epithermal neutrons. The other secondary source is the pulsed source of thermal neutrons that uses fast 14 MeV neutrons from a pulsed generator at the Institute of Nuclear Physics PAN in Krakow (Poland). The physical problems to be solved in the two mentioned cases are different. Namely, in order to devise the BNCT source the initial energy of particles ought to be increased, whilst in the other case the fast neutrons have to be moderated. Slowing down of neutrons is relatively easy since these particles lose energy when they scatter in media; the most effective moderators are the materials which contain light elements (mostly hydrogen). In order to increase the energy of neutrons from thermal to epithermal (the BNCT case) the so-called neutron converter should be exploited. It contains a fissile material, 235 U. The thermal neutrons from the reactor cause fission of uranium and fast neutrons are emitted from the converter. Then fissile neutrons of energy of a few MeV are slowed down to the required epithermal energy range. The design of both secondary sources have been conducted by means of Monte Carlo simulations, which have been carried out using the MCNP code. In the case of the secondary pulsed thermal neutron source, some of the calculated results have been verified experimentally. (author)

  1. Analysis of grain boundaries, twin boundaries, and Te precipitates in CdZnTe grown by high-pressure Bridgeman method

    International Nuclear Information System (INIS)

    Heffelfinger, J.R.; Medlin, D.L.; James, R.B.

    1998-03-01

    Grain boundaries and twin boundaries in commercial Cd 1-x Zn x Te, which is prepared by a high pressure Bridgeman technique, have been investigated with transmission electron microscopy, scanning electron microscopy, infrared light microscopy and visible light microscopy. Boundaries inside these materials were found to be decorated with Te precipitates. The shape and local density of the precipitates were found to depend on the particular boundary. For precipitates that decorate grain boundaries, their microstructure was found to consist of a single, saucer shaped grain of hexagonal Te (space group P3 1 21). Analysis of a Te precipitate precipitates by selected area diffraction revealed the Te to be aligned with the surrounding Cd 1-x Zn x Te grains. This alignment was found to match the (111) Cd 1-x Z x Te planes with the (1 bar 101) planes of hexagonal Te. Crystallographic alignments between the Cd 1-x Zn x Te grains were also observed for a high angle grain boundary. The structure of the grain boundaries and the Te/Cd 1-x Zn x Te interface are discussed

  2. Vitamin Deficiency Anemia

    Science.gov (United States)

    ... are unique to specific vitamin deficiencies. Folate-deficiency anemia risk factors include: Undergoing hemodialysis for kidney failure. ... the metabolism of folate. Vitamin B-12 deficiency anemia risk factors include: Lack of intrinsic factor. Most ...

  3. TLD-300 detectors for separate measurement of total and gamma absorbed dose distributions of single, multiple, and moving-field neutron treatments

    International Nuclear Information System (INIS)

    Rassow, J.

    1984-01-01

    Fast neutron therapy requirements, because of the poor depth dose characteristic of present therapeutical sources, are at least as complex in treatment plans as photon therapy. The physical part of the treatment planning is very important; however, it is much more complicated than for photons or electrons owing to the need for: Separation of total and gamma absorbed dose distributions (Dsub(T) and Dsub(G)); and more stringent tissue-equivalence conditions of phantoms than in photon therapy. Therefore, methods of clinical dosimetry for the separate determination of total and gamma absorbed dose distributions in irregularly shaped (inhomogeneous) phantoms are needed. A method using TLD-300 (CaF 2 :Tm) detectors is described, which is able to give an approximate solution of the above-mentioned dosimetric requirements. The two independent doses, Dsub(T) and Dsub(G), can be calculated by an on-line computer analysis of the digitalized glow curve of TLD-300 detectors, irradiated with d(14)+Be neutrons of the cyclotron isocentric neutron therapy facility CIRCE in Essen. Results are presented for depth and lateral absorbed dose distributions (Dsub(T) and Dsub(G)) for fixed neutron beams of different field sizes compared with measurements by standard procedures (TE-TE ionization chamber, GM counter) in an A-150 phantom. The TLD-300 results for multiple and moving-field treatments (with and without wedge filters) in a patient simulating irregularly shaped (inhomogeneous) phantoms, are shown together with computer calculations of these dose distributions. The probable causes for some systematic deviations are discussed, which lead to open problems for further investigations owing to features of the detector material and the evaluation method, but mainly to differences in the composition of phantom materials used for the calculations (standard dose distributions) and TLD-300 measurements. (author)

  4. Data for the neutron interactions with 6Li and 10B

    International Nuclear Information System (INIS)

    Poenitz, W.P.

    1984-01-01

    The 10 B(n,α), 10 B(n,α 1 ) and, increasingly in more recent measurement, the 6 Li(n,α) cross sections are the major references used in low energy experiments. Many data from modern measurements are available for the neutron interaction with 6 Li, including total, scattering, and absolute and relative (n,α) cross sections. A consensus has been reached with these new 6 Li + n data. In contrast, the data base for the 10 B neutron interaction cross sections is unfortunately poor. This is even the case for the total cross section which is supposed to be the easiest quantity to be measured. The most serious deficiency is the absence of data from absolute measurements of the 10 B(n,α) and 10 B(n,α 1 ) cross sections in the last 10 to 15 years. The available cross section data which were used for the ENDF/B-VI evaluation will be discussed. 43 references

  5. Calculations to support JET neutron yield calibration: Modelling of neutron emission from a compact DT neutron generator

    Science.gov (United States)

    Čufar, Aljaž; Batistoni, Paola; Conroy, Sean; Ghani, Zamir; Lengar, Igor; Milocco, Alberto; Packer, Lee; Pillon, Mario; Popovichev, Sergey; Snoj, Luka; JET Contributors

    2017-03-01

    At the Joint European Torus (JET) the ex-vessel fission chambers and in-vessel activation detectors are used as the neutron production rate and neutron yield monitors respectively. In order to ensure that these detectors produce accurate measurements they need to be experimentally calibrated. A new calibration of neutron detectors to 14 MeV neutrons, resulting from deuterium-tritium (DT) plasmas, is planned at JET using a compact accelerator based neutron generator (NG) in which a D/T beam impinges on a solid target containing T/D, producing neutrons by DT fusion reactions. This paper presents the analysis that was performed to model the neutron source characteristics in terms of energy spectrum, angle-energy distribution and the effect of the neutron generator geometry. Different codes capable of simulating the accelerator based DT neutron sources are compared and sensitivities to uncertainties in the generator's internal structure analysed. The analysis was performed to support preparation to the experimental measurements performed to characterize the NG as a calibration source. Further extensive neutronics analyses, performed with this model of the NG, will be needed to support the neutron calibration experiments and take into account various differences between the calibration experiment and experiments using the plasma as a source of neutrons.

  6. Calculations to support JET neutron yield calibration: Modelling of neutron emission from a compact DT neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Čufar, Aljaž, E-mail: aljaz.cufar@ijs.si [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Batistoni, Paola [ENEA, Department of Fusion and Nuclear Safety Technology, I-00044 Frascati, Rome (Italy); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Conroy, Sean [Uppsala University, Department of Physics and Astronomy, PO Box 516, SE-75120 Uppsala (Sweden); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Ghani, Zamir [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Lengar, Igor [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Milocco, Alberto; Packer, Lee [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Pillon, Mario [ENEA, Department of Fusion and Nuclear Safety Technology, I-00044 Frascati, Rome (Italy); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Popovichev, Sergey [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Snoj, Luka [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

    2017-03-01

    At the Joint European Torus (JET) the ex-vessel fission chambers and in-vessel activation detectors are used as the neutron production rate and neutron yield monitors respectively. In order to ensure that these detectors produce accurate measurements they need to be experimentally calibrated. A new calibration of neutron detectors to 14 MeV neutrons, resulting from deuterium–tritium (DT) plasmas, is planned at JET using a compact accelerator based neutron generator (NG) in which a D/T beam impinges on a solid target containing T/D, producing neutrons by DT fusion reactions. This paper presents the analysis that was performed to model the neutron source characteristics in terms of energy spectrum, angle–energy distribution and the effect of the neutron generator geometry. Different codes capable of simulating the accelerator based DT neutron sources are compared and sensitivities to uncertainties in the generator's internal structure analysed. The analysis was performed to support preparation to the experimental measurements performed to characterize the NG as a calibration source. Further extensive neutronics analyses, performed with this model of the NG, will be needed to support the neutron calibration experiments and take into account various differences between the calibration experiment and experiments using the plasma as a source of neutrons.

  7. Distinguishing new science from calibration effects in the electron-volt neutron spectrometer VESUVIO at ISIS

    Energy Technology Data Exchange (ETDEWEB)

    Chatzidimitriou-Dreismann, C.A., E-mail: dreismann@chem.tu-berlin.de [Institute of Chemistry (Sekr. C2), Technical University of Berlin, D-10623 Berlin (Germany); Gray, E. MacA., E-mail: e.gray@griffith.edu.au [Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane 4111 (Australia); Blach, T.P., E-mail: t.blach@griffith.edu.au [Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane 4111 (Australia)

    2012-06-01

    The 'standard' procedure for calibrating the Vesuvio eV neutron spectrometer at the ISIS neutron source, forming the basis for data analysis over at least the last decade, was recently documented in considerable detail by the instrument's scientists. Additionally, we recently derived analytic expressions of the sensitivity of recoil peak positions with respect to fight-path parameters and presented neutron-proton scattering results that together called into question the validity of the 'standard' calibration. These investigations should contribute significantly to the assessment of the experimental results obtained with Vesuvio. Here we present new results of neutron-deuteron scattering from D{sub 2} in the backscattering angular range ({theta}>90 Degree-Sign ) which are accompanied by a striking energy increase that violates the Impulse Approximation, thus leading unequivocally the following dilemma: (A) either the 'standard' calibration is correct and then the experimental results represent a novel quantum dynamical effect of D which stands in blatant contradiction of conventional theoretical expectations; (B) or the present 'standard' calibration procedure is seriously deficient and leads to artificial outcomes. For Case (A), we allude to the topic of attosecond quantum dynamical phenomena and our recent neutron scattering experiments from H{sub 2} molecules. For Case (B), some suggestions as to how the 'standard' calibration could be considerably improved are made.

  8. Study of neutron fields around an intense neutron generator.

    Science.gov (United States)

    Kicka, L; Machrafi, R; Miller, A

    2017-12-01

    Neutron fields in the vicinity of the newly built neutron facility, at the University of Ontario Institute of Technology (UOIT), have been investigated in a series of Monte Carlo simulations and measurements. The facility hosts a P-385 neutron generator based on a deuterium-deuterium fusion reaction. The neutron fluence at different locations around the neutron generator facility has been simulated using MCNPX 2.7E Monte Carlo particle transport program. To characterize neutron fields, three neutron sources were modeled with distributions corresponding to different incident deuteron energies of 90kV, 110kV, and 130kV. Measurements have been carried out to determine the dose rate at locations adjacent to the generator using bubble detectors (BDs). The neutron intensity was evaluated and the total dose rates corresponding to different applied acceleration potentials were estimated at various locations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Effect of Te atmosphere annealing on the properties of CdZnTe single crystals

    International Nuclear Information System (INIS)

    Yu Pengfei; Jie Wanqi; Wang Tao

    2011-01-01

    Low-resistivity CdZnTe:In (CZT:In) single crystals were annealed under Te atmosphere according to the behaviors of deep-donor Te antisite. The results indicated that the star-like Cd inclusions were completely eliminated after 120 h annealing. Meanwhile, the resistivity is greatly enhanced. The resistivity of the slice annealed after 240 h was achieved as high as 1.8x10 11 Ω cm, five orders of magnitude higher than that of as-grown slice. It suggested that the deep-donor level Te antisites were successfully introduced to pin the Fermi level at the mid band-gap position. The IR transmittances of the slices were also improved, which increased as the annealing time increased. PL measurement revealed that the (D 0 ,X) peak representing high quality of CZT crystal appeared. It can be concluded that the quality of CZT crystals is obviously improved after annealing under Te atmosphere. - Highlights: → High resistivity is due to deep-donor level Te Cd . → The resistivity achieved was as high as 1.8x10 11 Ω cm. → Star-like inclusions are Cd inclusions. → (D 0 ,X) peak represents the improvement of the crystal quality.

  10. Miscellaneous neutron techniques

    International Nuclear Information System (INIS)

    Iddings, F.A.

    1976-01-01

    Attention is brought to the less often uses of neutrons in the areas of neutron radiography, well logging, and neutron gaging. Emphasis on neutron radiography points toward the isotopic sensitivity of the method versus the classical bulk applications. Also recognized is the ability of neutron radiography to produce image changes that correspond to thickness and density changes obtained in photon radiography. Similarly, neutron gaging applications center on the measurement of radiography. Similarly, neutron gaging applications center on the measurement of water, oil, or plastics in industrial samples. Well logging extends the neutron gaging to encompass many neutron properties and reactions besides thermalization and capture. Neutron gaging also gives information on organic structure and concentrations of a variety of elements or specific compounds in selected matrices

  11. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... to moderate iron-deficiency anemia, or red blood cell transfusion for severe iron-deficiency anemia. You may ... body needs iron to make healthy red blood cells. Iron-deficiency anemia usually develops over time because ...

  12. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... you are diagnosed with iron-deficiency anemia. Risk Factors You may have an increased risk for iron- ... iron-deficiency anemia if you have certain risk factors , including pregnancy. To prevent iron-deficiency anemia, your ...

  13. Discovery of the neutron (to the fiftieth anniversary of neutron discovery)

    International Nuclear Information System (INIS)

    Pasechnik, M.V.

    1984-01-01

    Development of neutron physics in the USSR for the recent 50 years from the moment of neutron discovery is considered. History of neutron discovery is presented in brief. Neutron properties and fundamental problems of physics: electric dipole neutron moment, neutron β-decay, neutron interaction with nuclei and potential of nucleon interaction not conserving spatial parity are discussed. Main aspects of neutron physics application in power engineering, nuclear technology and other branches of science and technique are set forth

  14. Neutron rich matter, neutron stars, and their crusts

    International Nuclear Information System (INIS)

    Horowitz, C J

    2011-01-01

    Neutron rich matter is at the heart of many fundamental questions in Nuclear Physics and Astrophysics. What are the high density phases of QCD? Where did the chemical elements come from? What is the structure of many compact and energetic objects in the heavens, and what determines their electromagnetic, neutrino, and gravitational-wave radiations? Moreover, neutron rich matter is being studied with an extraordinary variety of new tools such as Facility for Rare Isotope Beams (FRIB) and the Laser Interferometer Gravitational Wave Observatory (LIGO). We describe the Lead Radius Experiment (PREX) that is using parity violation to measure the neutron radius in 208Pb. This has important implications for neutron stars and their crusts. Using large scale molecular dynamics, we model the formation of solids in both white dwarfs and neutron stars. We find neutron star crust to be the strongest material known, some 10 billion times stronger than steel. It can support mountains on rotating neutron stars large enough to generate detectable gravitational waves. Finally, we describe a new equation of state for supernova and neutron star merger simulations based on the Virial expansion at low densities, and large scale relativistic mean field calculations.

  15. Kinetic barriers for Cd and Te adatoms on Cd and Te terminated CdTe (111) surface using ab initio simulations

    Science.gov (United States)

    Naderi, Ebadollah; Nanavati, Sachin P.; Majumder, Chiranjib; Ghaisas, S. V.

    2014-03-01

    In the present work we have calculated using density functional theory (DFT), diffusion barrier potentials on both the CdTe (111) surfaces, Cd terminated (A-type) & Te terminated (B-type). We employ nudge elastic band method (NEB) for obtaining the barrier potentials. The barrier is computed for Cd and for Te adatoms on both A-type and B-type surfaces. We report two energetically favourable positions along the normal to the surface, one above and other below the surface. The one above the surface has binding energy slightly more the one below. According to the results of this work, binding energy (in all cases) for adatoms are reasonable and close to experimental data. The barrier potential for hopping adatoms (Cd and Te) on both the surfaces is less than 0.35 eV. Apart from these most probable sites, there are other at least two sites on both the types of surfaces which are meta stable. We have also computed barriers for hopping to and from these meta stable positions. The present results can shade light on the defect formation mechanism in CdTe thin films during growth. The authors would like to thank C-DAC for the computing time on its PARAM series of supercomputers and DST Govt. of India, for partial funding.

  16. First-principles study of lattice thermal conductivity in ZrTe5 and HfTe5

    Science.gov (United States)

    Wang, Cong; Wang, Haifeng; Chen, Y. B.; Yao, Shu-Hua; Zhou, Jian

    2018-05-01

    Recently, the layered transition-metal pentatellurides ZrTe5 and HfTe5 have attracted increasing attention because of their interesting topological electronic properties. Nevertheless, some of their other good physical properties seem to be ignored now. Actually, both ZrTe5 and HfTe5 have high electric conductivities (>105 Ω-1 m-1) and Seebeck coefficients (> 100 μV/K) at room temperature, thus making them promising thermoelectric materials. However, the disadvantage is that the thermal conductivities of the two materials are relatively high according to the few available experiments; meanwhile, the detailed mechanism of the intrinsic thermal conductivity has not been studied yet. Based on the density functional theory and the Boltzmann transport theory, we present here the theoretical study of the intrinsic lattice thermal conductivities of ZrTe5 and HfTe5, which are found to be in the range of 5-8 W/mṡK at room temperature and well consistent with the experimental results. We also find that the thermal conductivities of the two materials are anisotropic, which are mainly caused by their anisotropic crystal structures. Based on the detailed analysis, we proposed that the thermal conductivities of the two materials could possibly be reduced by different kinds of structural engineering at the atomic and mesoscopic scales, such as alloying, doping, nano-structuring, and polycrystalline structuring, which could make ZrTe5 and HfTe5 good thermoelectric materials for room temperature thermoelectric applications.

  17. What Are Rare Clotting Factor Deficiencies?

    Science.gov (United States)

    ... Deficiency Factor V Deficiency Combined FV & FVIII Deficiencies Factor VII Deficiency Factor X Deficiency Factor XI Deficiency Factor ... Deficiency Factor V Deficiency Combined FV & FVIII Deficiencies Factor VII Deficiency Factor X Deficiency Factor XI Deficiency Factor ...

  18. Crystallization and memory programming characteristics of Ge-doped SbTe materials of varying Sb : Te ratio

    International Nuclear Information System (INIS)

    Jeong, Jeung-hyun; Lee, Hyun Seok; Lee, Suyoun; Lee, Taek Sung; Kim, Won Mok; Wu Zhe; Cheong, Byung-ki; Kim, Seul Cham; Oh, Kyu Hwan

    2009-01-01

    A phase change memory (PCM) utilizes resistivity changes accompanying fast transitions from an amorphous to a crystalline phase (SET) and vice versa (RESET). An investigation was made on the SET characteristics of PCM cells with Ge-doped SbTe (Ge-ST) materials of two different Sb : Te ratios (4.53 and 2.08). For the material of higher Sb : Te (4.53), a SET operation was completed within several tens of nanoseconds via nucleation-free crystallization whereas the material of lower Sb : Te (2.08) rendered a slower SET operation requiring several hundred nanoseconds for a nucleation-mediated crystallization. From measurements of nucleation and growth kinetics via laser-induced crystallization, the observed SET characteristics of the former case were found to derive from a growth time about 10 3 times shorter than the nucleation time and those of the latter from a much shorter nucleation time as well as a longer growth time than in the former case. The measured nucleation kinetics of the lower Sb : Te (2.08) material is unexpected from the existing data, which has led us to advance an interesting finding that there occurs a trend-reversing change in the nucleation kinetics of the Ge-ST materials around the eutectic composition (Sb : Te ∼2.6); nucleation is accelerated with the increase in the Sb : Te ratio above Sb : Te of 2.6, but with a decrease in the Sb : Te ratio below it.

  19. Schreibende Messgeräte

    Science.gov (United States)

    Plaßmann, Wilfried

    Die schreibenden Messgeräte werden hauptsächlich eingesetzt, um Vorgänge aufzuzeichnen und zu dokumentieren, die sich im Minuten- und Stunden-Bereich abspielen. Sie sind weitgehend durch Oszilloskope oder elektronische Geräte ähnlich einem Oszilloskop ersetzt worden, die entsprechend für Langzeitaufnahmen ausgelegt sind. Der Vorteil dieser Geräte gegenüber den schreibenden Messgeräten ist der, dass die Daten dauerhaft gespeichert sind, einschließlich der notwendigen Kenngrößen wie Zeitmaßstab, Amplitude, Datum, Aufzeichnungsgerät usw., und sich in dieser Form beliebig oft ausdrucken und vor allem direkt weiterverarbeiten lassen. Weiterhin entfallen die Probleme mit der Mechanik, dem Papier und den Schreibstiften. Deshalb folgt hier eine nur kurze Darstellung der Geräte.

  20. Neutron induced fission cross sections for 232Th, 235,238U, 237Np, and 239Pu

    International Nuclear Information System (INIS)

    Lisowski, P.W.; Ullmann, J.L.; Balestrini, S.J.; Hill, N.W.; Carlson, A.D.; Wasson, O.A.

    1989-01-01

    Neutron-induced fission cross section ratios for samples of 232 Th, 235,238 U, 237 Np and 239 Pu have been measured from 1 to 400 MeV. The fission reaction rate was determined for all samples simultaneously using a fast parallel plate ionization chamber at a 20-m flight path. A well characterized annular proton recoil telescope was used to measure the neutron fluence from 3 to 30 MeV. Those data provided the shape of the 235 U(n,f) cross section relative to the hydrogen scattering cross section. That shape was then normalized to the very accurately known value for 235 U(n,f) at 14.178 MeV. From 30 to 400 MeV cross section values were determined using the neutron fluence measured with a plastic scintillator. Cross section values of 232 Th, 235,238 U, 237 Np and 239 Pu were computed from the ratio data using the authors' values for 235 U(n,f). In addition to providing new results at high neutron energies, these data highlight several areas of deficiency in the evaluated nuclear data files and provide new information for the 235 U(n,f) standard

  1. Study on the cause of iron-deficiency anemia in adolescent athletes by INAA with enriched stable isotopes

    International Nuclear Information System (INIS)

    Qian, Q.F.; Wu, S.Q.; Tian, J.B.; Huo, Z.P.; Chen, J.D.; Li, K.J.

    1991-01-01

    Iron deficiency anemia is still one of the most common nutritional deficiency diseases throughout the world. The incidence of iron deficiency is high especially in children, adolescent, and endurance athletes. The authors studied the iron absorption rate and iron balance in six child football players during training and non-training periods. The neutron activation method with enriched stable isotope 58Fe has been adopted. The results show that the rate of iron absorption in athletes during the training period (9.1 + 2.9%) was significantly lower than that during the non-training period (11.9 + 4.7%); the iron balance was negative and the sweat iron loss increased during training. Hair is one of the metabolism excretory organs. The physiological changes of body would influence the trace element contents in hair. The hairs collected from four athletes were measured by Synchrotron-induced X-ray Fluorescence analysis, so as to get the trace element contents. Preliminary results show that the changes of iron content in the hairs are in accordance with the athlete's physical activity. There are no perceptible changes for Zn and Ca. It is verified that exercise is one of the causes of iron deficiency in athletes. It is necessary to increase iron supply in an athletes' nutritional intake to ensure optimal performance ability

  2. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... for iron-deficiency anemia if you have certain risk factors , including pregnancy. To prevent iron-deficiency anemia, your doctor may recommend you eat heart-healthy foods or control other conditions that can cause iron-deficiency anemia. ...

  3. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Home / < Back To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español ... bleeding Consuming less than recommended daily amounts of iron Iron-deficiency anemia can be caused by getting ...

  4. Neutron Beam Filters

    International Nuclear Information System (INIS)

    Adib, M.

    2011-01-01

    The purpose of filters is to transmit neutrons with selected energy, while remove unwanted ones from the incident neutron beam. This reduces the background, and the number of spurious. The types of commonly used now-a-day neutron filters and their properties are discussed in the present work. There are three major types of neutron filters. The first type is filter of selective thermal neutron. It transmits the main reflected neutrons from a crystal monochromate, while reject the higher order contaminations accompanying the main one. Beams coming from the moderator always contain unwanted radiation like fast neutrons and gamma-rays which contribute to experimental background and to the biological hazard potential. Such filter type is called filter of whole thermal neutron spectrum. The third filter type is it transmits neutrons with energies in the resonance energy range (En . 1 KeV). The main idea of such neutron filter technique is the use of large quantities of a certain material which have the deep interference minima in its total neutron cross-section. By transmitting reactor neutrons through bulk layer of such material, one can obtain the quasimonochromatic neutron lines instead of white reactor spectrum.

  5. Neutron stochastic transport theory with delayed neutrons

    International Nuclear Information System (INIS)

    Munoz-Cobo, J.L.; Verdu, G.

    1987-01-01

    From the stochastic transport theory with delayed neutrons, the Boltzmann transport equation with delayed neutrons for the average flux emerges in a natural way without recourse to any approximation. From this theory a general expression is obtained for the Feynman Y-function when delayed neutrons are included. The single mode approximation for the particular case of a subcritical assembly is developed, and it is shown that Y-function reduces to the familiar expression quoted in many books, when delayed neutrons are not considered, and spatial and source effects are not included. (author)

  6. Structural phase transitions in the ordered double perovskite Sr2MnTeO6

    International Nuclear Information System (INIS)

    Ortega-San Martin, L; Chapman, J P; Hernandez-Bocanegra, E; Insausti, M; Arriortua, M I; Rojo, T

    2004-01-01

    The crystal structure of the ordered double perovskite Sr 2 MnTeO 6 has been refined at ambient temperature from high resolution neutron and x-ray powder diffraction data in the monoclinic space group P 12 1 /n 1 with a 5.7009(1) A, b = 5.6770(1) A, c = 8.0334(1) A and β = 90.085(1) deg. This represents a combination of in-phase (+) and out-of-phase (-) rotations of virtually undistorted MnO 6 and TeO 6 octahedra in the (-+) sense about the axes of the ideal cubic perovskite. High temperature x-ray powder diffraction shows three structural phase transitions at approximately 250, 550 and 675 deg. C, each corresponding to the disappearance of rotations about one of these axes. The first transition was analysed by differential scanning calorimetry and showed a thermal hysteresis with an enthalpy of 0.55 J g -1 . We propose the (P12 1 /n1 → I12/m1 → I4/m → Fm3barm) sequence of structural transitions which has not been previously reported for a double perovskite oxide

  7. Fundamental of neutron radiography and the present of neutron radiography in Japan

    International Nuclear Information System (INIS)

    Sekita, Junichiro

    1988-01-01

    Neutron radiography refers to the application of transmitted neutrons to analysis. In general, thermal neutron is used for neutron radiography. Thermal neutron is easily absorbed by light atoms, including hydrogen, boron and lithium, while it is not easily absorbed by such heavy atoms as tungsten, lead and uranium, permitting detection of impurities in heavy metals. Other neutrons than thermal neutron can also be applied. Cold neutron is produced from fast neutron using a moderator to reduce its energy down to below that of thermal neutron. Cold neutron is usefull for analysis of thick material. Epithermal neutron can induce resonance characteristic of each substance. With a relatively small reaction area, fast neutron permits observation of thick samples. Being electrically neutral, neutrons are difficult to detect by direct means. Thus a substance that releases charged particles is put in the path of neutrons for indirect measurement. X-ray film combined with converter screen for conversion of neutrons to charge particles is placed behind the sample. Photographing is carried out by a procedure similar to X-ray photography. Major institues and laboratories in Japan provided with neutron radiography facilities are listed. (Nogami, K.)

  8. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... anemia, your doctor may order the following blood tests to diagnose iron-deficiency anemia: Complete blood count (CBC) to ... than normal when viewed under a microscope. Different tests help your doctor diagnose iron-deficiency anemia. In iron-deficiency anemia, blood ...

  9. Determination of equilibrium phase composition in the Hg-HgTe-CdTe system by ''dew point'' method

    International Nuclear Information System (INIS)

    Vanyukov, A.V.; Krotov, I.I.; Ermakov, A.I.

    1978-01-01

    Using the ''dew point'' method a study has been made of the equilibrium composition of the solid and liquid phases in the Hg-HgTe-CdTe system at 404, 435 and 454 deg C. It has been pointed out that crystallization of cadmium-rich solid solutions of Cdsub(x)Hgsub(1-x) Te takes place from a liquid phase with a much higher concentration of Hg. The activity of Hg in the liquid phase increases along the liquidus isotherm in the direction from section Hg-HgTe to section HgCdTe in accordance with the increase of its concentration. An increase in activity of Hg in the solid phase of Cdsub(x)Hgsub(1-x)Te has been noted with the reduction of its concentration

  10. Review of Non-Neutron and Neutron Nuclear Data, 2004

    International Nuclear Information System (INIS)

    Holden, Norman E.

    2005-01-01

    Review articles are in preparation for the 2004 edition of the CRC Handbook of Chemistry and Physics dealing with the evaluation of both non-neutron and neutron nuclear data. Data on the discovery of element 110, Darmstadtium, and element 111 have been officially accepted, while data on element 118 have been withdrawn. Data to be presented include revised values for very short-lived nuclides, long-lived nuclides, and beta-beta decay measurements. There has been a reassessment of the spontaneous fission (sf) half-lives, which distinguishes between sf decay half-lives and cluster decay half-lives, and with cluster-fission decay. New measurements of isotopic abundance values for many elements will be discussed with an emphasis on the minor isotopes of interest for use in neutron activation analysis measurements. Neutron resonance integrals will be discussed emphasizing the differences between the calculated values obtained from the analytical integration over neutron resonances and the measured values in a neutron reactor-spectrum, which does not quite conform to the assumed 1/E neutron energy spectrum. The method used to determine the neutron resonance integral from measurement, using neutron activation analysis, will be discussed

  11. Self-Catalyzed CdTe Wires

    Directory of Open Access Journals (Sweden)

    Tom Baines

    2018-04-01

    Full Text Available CdTe wires have been fabricated via a catalyst free method using the industrially scalable physical vapor deposition technique close space sublimation. Wire growth was shown to be highly dependent on surface roughness and deposition pressure, with only low roughness surfaces being capable of producing wires. Growth of wires is highly (111 oriented and is inferred to occur via a vapor-solid-solid growth mechanism, wherein a CdTe seed particle acts to template the growth. Such seed particles are visible as wire caps and have been characterized via energy dispersive X-ray analysis to establish they are single phase CdTe, hence validating the self-catalysation route. Cathodoluminescence analysis demonstrates that CdTe wires exhibited a much lower level of recombination when compared to a planar CdTe film, which is highly beneficial for semiconductor applications.

  12. CdCl2 passivation of polycrystalline CdMgTe and CdZnTe absorbers for tandem photovoltaic cells

    Science.gov (United States)

    Swanson, Drew E.; Reich, Carey; Abbas, Ali; Shimpi, Tushar; Liu, Hanxiao; Ponce, Fernando A.; Walls, John M.; Zhang, Yong-Hang; Metzger, Wyatt K.; Sampath, W. S.; Holman, Zachary C.

    2018-05-01

    As single-junction silicon solar cells approach their theoretical limits, tandems provide the primary path to higher efficiencies. CdTe alloys can be tuned with magnesium (CdMgTe) or zinc (CdZnTe) for ideal tandem pairing with silicon. A II-VI/Si tandem holds the greatest promise for inexpensive, high-efficiency top cells that can be quickly deployed in the market using existing polycrystalline CdTe manufacturing lines combined with mature silicon production lines. Currently, all high efficiency polycrystalline CdTe cells require a chloride-based passivation process to passivate grain boundaries and bulk defects. This research examines the rich chemistry and physics that has historically limited performance when extending Cl treatments to polycrystalline 1.7-eV CdMgTe and CdZnTe absorbers. A combination of transmittance, quantum efficiency, photoluminescence, transmission electron microscopy, and energy-dispersive X-ray spectroscopy clearly reveals that during passivation, Mg segregates and out-diffuses, initially at the grain boundaries but eventually throughout the bulk. CdZnTe exhibits similar Zn segregation behavior; however, the onset and progression is localized to the back of the device. After passivation, CdMgTe and CdZnTe can render a layer that is reduced to predominantly CdTe electro-optical behavior. Contact instabilities caused by inter-diffusion between the layers create additional complications. The results outline critical issues and paths for these materials to be successfully implemented in Si-based tandems and other applications.

  13. Diffusion and influence of Cu on properties of CdTe thin films and CdTe/CdS cells

    Energy Technology Data Exchange (ETDEWEB)

    Dzhafarov, T.D.; Yesilkaya, S.S.; Yilmaz Canli, N.; Caliskan, M. [Department of Physics, Yildiz Technical University, Davutpasa, 34210 Istanbul (Turkey)

    2005-01-31

    The effective diffusion coefficients of Cu for thermal and photodiffusion in the CdTe films have been estimated from resistivity versus duration of thermal or photoannealing curves. In the temperature range 60-200{sup o}C the effective coefficient of thermal diffusion (D{sub t}) and photodiffusion (D{sub ph}) are described as D{sub t}=7.3x10{sup -7}exp(-0.33/kT) and D{sub ph}=4.7x10{sup -8}exp(-0.20/kT). It is found that the diffusion doping of CdTe thin films by Cu at 400{sup o}C results in a sharp decrease of resistivity up to 7 orders of magnitude of p-type material, depending on thickness of Cu film. The comparative study of performance of CdTe(Cu)/CdS and CdTe/CdS cells has been studied. It is shown that the diffusion doping of CdTe film by Cu increases efficiency of CdTe(Cu)/CdS cells from 0.9% to 6.8%. The degradation of photovoltaic parameters of CdTe(Cu)/CdS cell, during testing under forward and reverse bias at room temperature, proceeds at a larger rate than those of CdTe/CdS cell without Cu. The degradation of performance of CdTe(Cu)/CdS cells is tentatively assigned to electrodiffusion of Cu in CdTe, resulting in redistribution of concentration of Cu-related centers in CdTe film and heterojunction region.

  14. Observation of Neutron Skyshine from an Accelerator Based Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Franklyn, C. B. [Radiation Science Department, Necsa, PO Box 582, Pretoria 0001 (South Africa)

    2011-12-13

    A key feature of neutron based interrogation systems is the need for adequate provision of shielding around the facility. Accelerator facilities adapted for fast neutron generation are not necessarily suitably equipped to ensure complete containment of the vast quantity of neutrons generated, typically >10{sup 11} n{center_dot}s{sup -1}. Simulating the neutron leakage from a facility is not a simple exercise since the energy and directional distribution can only be approximated. Although adequate horizontal, planar shielding provision is made for a neutron generator facility, it is sometimes the case that vertical shielding is minimized, due to structural and economic constraints. It is further justified by assuming the atmosphere above a facility functions as an adequate radiation shield. It has become apparent that multiple neutron scattering within the atmosphere can result in a measurable dose of neutrons reaching ground level some distance from a facility, an effect commonly known as skyshine. This paper describes a neutron detection system developed to monitor neutrons detected several hundred metres from a neutron source due to the effect of skyshine.

  15. Health Deficiencies

    Data.gov (United States)

    U.S. Department of Health & Human Services — A list of all health deficiencies currently listed on Nursing Home Compare, including the nursing home that received the deficiency, the associated inspection date,...

  16. Pulsed neutron uranium borehole logging with prompt fission neutrons

    International Nuclear Information System (INIS)

    Bivens, H.M.; Smith, G.W.; Jensen, D.H.

    1976-01-01

    The gross count natural gamma log normally used for uranium borehole logging is seriously affected by disequilibrium. Methods for the direct measurement of uranium, such as neutron logging, which are not affected by disequilibrium have been the object of considerable effort in recent years. This paper describes a logging system for uranium which uses a small accelerator to generate pulses of 14 MeV neutrons to detect and assay uranium by the measurement of prompt fission neutrons in the epithermal energy range. After an initial feasibility study, a prototype logging probe was built for field evaluation which began in January 1976. Physical and operational characteristics of the prototype probe, the neutron tube-transformer assembly, and the neutron tube are described. In logging operations, only the epithermal prompt fission neutrons detected between 250 microseconds to 2500 microseconds following the excitation neutron pulse are counted. Comparison of corrected neutron logs with the conventional gross count natural gamma logs and the chemical assays of cores from boreholes are shown. The results obtained with this neutron probe clearly demonstrate its advantages over the gross count natural gamma log, although at this time the accuracy of the neutron log assay is not satisfactory under some conditions. The necessary correction factors for various borehole and formation parameters are being determined and, when applied, should improve the assay accuracy

  17. Neutron reflectometry

    International Nuclear Information System (INIS)

    Van Well, A.A.

    1999-01-01

    Neutron research where reflection, refraction, and interference play an essential role is generally referred to as 'neutron optics'. The neutron wavelength, the scattering length density and the magnetic properties of the material determine the critical angle for total reflection. The theoretical background of neutron reflection, experimental methods and the interpretation of reflection data are presented. (K.A.)

  18. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... if you are diagnosed with iron-deficiency anemia. Risk Factors You may have an increased risk for iron-deficiency anemia because of your age, ... or sex. Age You may be at increased risk for iron deficiency at certain ages: Infants between ...

  19. Study of CdTe:Cl and CdZnTe detectors for medical multi-slices X-ray Computed Tomography; Etude de detecteurs en CdTe:Cl et CdZnTe pour la tomographie X medicale multicoupes

    Energy Technology Data Exchange (ETDEWEB)

    Ricq, St

    1999-09-28

    The application of CdTe and CdZnTe detectors to medical X-ray Computed Tomography have been investigated. Different electrodes (Au, Pt, In) have been deposited on CdZnTe HPBM and on CdTe:ClTHM. Their injection properties have been determined with Current-Voltage characteristics. Under X-ray in CT conditions, injection currents measurements reveal trapped carriers space-charges formation. The same way, the comparisons of the responses to X-beam cut-off with various injection possibilities enable to follow the space-charges evolutions and then to determine the predominant traps types. Nevertheless, both hole and electron traps are responsible for the memory effect e.g. the currents levels dependence with irradiation history. This effect is noticed in particular on responses to fast flux variations that simulate scanner's conditions. Trap levels probably corresponding to native defects are responsible for these limitations. In order to make such detectors suitable for X-ray Computed Tomography, significant progresses in CdTe for CdZnTe crystal growth with an important defects densities reduction (factor 10), or possibly counting mode operation, seem necessary. (author)

  20. Pulsed neutron generator for use with pulsed neutron activation techniques

    International Nuclear Information System (INIS)

    Rochau, G.E.

    1980-01-01

    A high-output, transportable, pulsed neutron generator has been developed by Sandia National Laboratories for use with Pulsed Neutron Activation (PNA) techniques. The PNA neutron generator generates > 10 10 14 MeV D-T neutrons in a 1.2 millisecond pulse. Each operation of the unit will produce a nominal total neutron output of 1.2 x 10 10 neutrons. The generator has been designed to be easily repaired and modified. The unit requires no additional equipment for operation or measurement of output

  1. Neutron irradiation behavior of ITER candidate beryllium grades

    Energy Technology Data Exchange (ETDEWEB)

    Kupriyanov, I.B.; Gorokhov, V.A.; Nikolaev, G.N. [A.A.Bochvar All-Russia Scientific Research Inst. of Inorganic Materials (VNIINM), Moscow (Russian Federation); Melder, R.R.; Ostrovsky, Z.E.

    1998-01-01

    Beryllium is one of the main candidate materials both for the neutron multiplier in a solid breeding blanket and for the plasma facing components. That is why its behaviour under the typical for fusion reactor loading, in particular, under the neutron irradiation is of a great importance. This paper presents mechanical properties, swelling and microstructure of six beryllium grades (DshG-200, TR-30, TshG-56, TRR, TE-30, TIP-30) fabricated by VNIINM, Russia and also one - (S-65) fabricated by Brush Wellman, USA. The average grain size of the beryllium grades varied from 8 to 25 {mu}m, beryllium oxide content was 0.8-3.2 wt. %, initial tensile strength was 250-680 MPa. All the samples were irradiated in active zone of SM-3 reactor up to the fast neutron fluence (5.5-6.2) {center_dot} 10{sup 21} cm{sup -2} (2.7-3.0 dpa, helium content up to 1150 appm), E > 0.1 MeV at two temperature ranges: T{sub 1} = 130-180degC and T{sub 2} = 650-700degC. After irradiation at 130-180degC no changes in samples dimensions were revealed. After irradiation at 650-700degC swelling of the materials was found to be in the range 0.1-2.1 %. Beryllium grades TR-30 and TRR, having the smallest grain size and highest beryllium oxide content, demonstrated minimal swelling, which was no more than 0.1 % at 650-700degC and fluence 5.5 {center_dot} 10{sup 21} cm{sup -2}. Tensile and compression test results and microstructure parameters measured before and after irradiation are also presented. (author)

  2. Neutron nuclear physics under the neutron science project

    Energy Technology Data Exchange (ETDEWEB)

    Chiba, Satoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-11-01

    The concept of fast neutron physics facility in the Neutron Science Research project is described. This facility makes use of an ultra-short proton pulse (width < 1 ns) for fast neutron time-of-flight works. The current design is based on an assumption of the maximum proton current of 100 {mu}A. Available neutron fluence and energy resolution are explained. Some of the research subjects to be performed at this facility are discussed. (author)

  3. Development of highly effective neutron shields and neutron absorbing materials

    International Nuclear Information System (INIS)

    Tsuda, K.; Matsuda, F.; Taniuchi, H.; Yuhara, T.; Iida, T.

    1993-01-01

    A wide range of materials, including polymers and hydrogen-occluded alloys that might be usable as the neutron shielding material were examined. And a wide range of materials, including aluminum alloys that might be usable as the neutron-absorbing material were examined. After screening, the candidate material was determined on the basis of evaluation regarding its adaptabilities as a high-performance neutron-shielding and neutron-absorbing material. This candidate material was manufactured for trial, after which material properties tests, neutron-shielding tests and neutron-absorbing tests were carried out on it. The specifications of this material were thus determined. This research has resulted in materials of good performance; a neutron-shielding material based on ethylene propylene rubber and titanium hydride, and a neutron-absorbing material based on aluminum and titanium hydride. (author)

  4. Methods for absorbing neutrons

    Science.gov (United States)

    Guillen, Donna P [Idaho Falls, ID; Longhurst, Glen R [Idaho Falls, ID; Porter, Douglas L [Idaho Falls, ID; Parry, James R [Idaho Falls, ID

    2012-07-24

    A conduction cooled neutron absorber may include a metal matrix composite that comprises a metal having a thermal neutron cross-section of at least about 50 barns and a metal having a thermal conductivity of at least about 1 W/cmK. Apparatus for providing a neutron flux having a high fast-to-thermal neutron ratio may include a source of neutrons that produces fast neutrons and thermal neutrons. A neutron absorber positioned adjacent the neutron source absorbs at least some of the thermal neutrons so that a region adjacent the neutron absorber has a fast-to-thermal neutron ratio of at least about 15. A coolant in thermal contact with the neutron absorber removes heat from the neutron absorber.

  5. Nb/sub 2/Te/sub 2/O/sub 9/ and Ta/sub 2/Te/sub 2/O/sub 9/: Two new mixed oxides of Te(IV)

    International Nuclear Information System (INIS)

    Gaitan, M.; Jerez, A.; Pico, C.; Veiga, M.L.

    1987-01-01

    Nb/sub 2/Te/sub 2/O/sub 9/ and Ta/sub 2/Te/sub 2/O/sub 9/ were prepared by solid state reactions between amorphous TeO/sub 3/(s) and metallic pentoxides of Nb and Ta. A crystallographic analysis carried out by X-ray diffraction showed that these compounds are isostructural (space group: P2/sub 1//C. a = 6.883 A, b = 7.853 A, c = 14.591 A, β = 103.66 for Nb/sub 2/Te/sub 2/O/sub 9/ and a = 7.10 A, b = 7.48 A, c = 14.62 A, β = 102.9 for Ta/sub 2/Te/sub 2/O/sub 9/). The IR spectra and thermal decomposition processes of both mixed oxides were studied

  6. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Topics News & Resources Intramural Research Home / < Back To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer ... and symptoms as well as complications from iron-deficiency anemia. Research for Your Health The NHLBI is part of the U.S. Department ...

  7. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2013-01-01

    The following topics are dealt with: Neutron sources, symmetry of crystals, nanostructures investigated by small-angle neutron scattering, structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic neutron scattering, strongly correlated electrons, polymer dynamics, applications of neutron scattering. (HSI)

  8. Bacon, Lettuce and Tomato: een strategie om leerlingen te helpen hun antwoorden op examenvragen te verbeteren

    NARCIS (Netherlands)

    Kneppers, L.

    2014-01-01

    In Tutor2u las ik dat in een workshop een strategie was besproken om leerlingen te helpen hun examenantwoorden vollediger en juister te formuleren. De strategie heet in Groot Brittannië BLT, voor leerlingen daar gemakkelijk te onthouden vanwege de populaire Bacon, Lettuce en Tomato sandwich.

  9. HgTe based topological insulators

    International Nuclear Information System (INIS)

    Bruene, Christoph

    2014-01-01

    This PhD thesis summarizes the discovery of topological insulators and highlights the developments on their experimental observations. The work focuses on HgTe. The thesis is structured as follows: - The first chapter of this thesis will give a brief overview on discoveries in the field of topological insulators. It focuses on works relevant to experimental results presented in the following chapters. This includes a short outline of the early predictions and a summary of important results concerning 2-dimensional topological insulators while the final section discusses observations concerning 3-dimensional topological insulators. - The discovery of the quantum spin Hall effect in HgTe marked the first experimental observation of a topological insulator. Chapter 2 focuses on HgTe quantum wells and the quantum spin Hall effect. The growth of high quality HgTe quantum wells was one of the major goals for this work. In a final set of experiments the spin polarization of the edge channels was investigated. Here, we could make use of the advantage that HgTe quantum well structures exhibit a large Rashba spin orbit splitting. - HgTe as a 3-dimensional topological insulator is presented in chapter 3. - Chapters 4-6 serve as in depth overviews of selected works: Chapter 4 presents a detailed overview on the all electrical detection of the spin Hall effect in HgTe quantum wells. The detection of the spin polarization of the quantum spin Hall effect is shown in chapter 5 and chapter 6 gives a detailed overview on the quantum Hall effect originating from the topological surface state in strained bulk HgTe.

  10. Development of Cold Neutron Activation Station at HANARO Cold Neutron Source

    International Nuclear Information System (INIS)

    Sun, G. M.; Hoang, S. M. T.; Moon, J. H.; Chung, Y. S.; Cho, S. J.; Lee, K. H.; Park, B. G.; Choi, H. D.

    2012-01-01

    A new cold neutron source at the HANARO Research Reactor had been constructed in the framework of a five-year project, and ended in 2009. It has seven neutron guides, among which five guides were already allocated for a number of neutron scattering instruments. A new two-year project to develop a Cold Neutron Activation Station (CONAS) was carried out at the two neutron guides since May 2010, which was supported by the program of the Ministry of Education, Science and Technology, Korea. Fig. 1 shows the location of CONAS. CONAS is a complex facility including several radioanalytical instruments utilizing neutron capture reaction to analyze elements in a sample. It was designed to include three instruments like a CN-PGAA (Cold Neutron - Prompt Gamma Activation Analysis), a CN-NIPS (Cold Neutron - Neutron Induced Pair Spectrometer), and a CN-NDP (Cold Neutron - Neutron-induced prompt charged particle Depth Profiling). Fig. 2 shows the conceptual configuration of the CONAS concrete bioshield and the instruments. CN-PGAA and CN-NIPS measure the gamma-rays promptly emitted from the sample after neutron capture, whereas CN-NDP is a probe to measure the charged particles emitted from the sample surface after neutron capture. For this, we constructed two cold neutron guides called CG1 and CG2B guides from the CNS

  11. Evolution of collectivity in neutron-rich nuclei in the 132Sn region

    International Nuclear Information System (INIS)

    Kshetri, Ritesh; Sarkar, M. Saha; Sarkar, S.

    2006-01-01

    Motivated by the observed regularity in the energy spectra and the structure of the shell model wave functions for the levels of 137 Te and 137 I, a few weakly and moderately deformed neutron-rich odd-A nuclei above the doubly magic nucleus 132 Sn were studied using the particle rotor model (PRM). The calculated energy spectra and branching ratios agree reasonably well with the most recent experimental data. In a few cases ambiguity in level ordering was resolved and spin-parities were assigned to the levels. Observed octupole correlation in some of these nuclei is discussed in the light of the present results

  12. Constructing nanoporous carbon nanotubes/Bi2Te3 composite for synchronous regulation of the electrical and thermal performances

    Science.gov (United States)

    Zhang, Qihao; Xu, Leilei; Zhou, Zhenxing; Wang, Lianjun; Jiang, Wan; Chen, Lidong

    2017-02-01

    Porous nanograined thermoelectric materials exhibit low thermal conductivity due to scattering of phonons by pores, which are favorable for thermoelectric applications. However, the benefit is not large enough to overcome the deficiency in the electrical performance. Herein, an approach is presented to reduce the thermal conductivity and synchronously enhance the electrical conductivity through constructing a nanoporous thermoelectric composite. Carbon nanotubes (CNTs) are truncated and homogeneously dispersed within the Bi2Te3 matrix by a cryogenic grinding (CG) technique for the first time, which efficiently suppress the Bi2Te3 grain growth and create nanopores with the size ranging from dozens to hundreds of nanometers. The lattice thermal conductivity is substantially decreased by broad wavelength phonon scattering resulting from nanopores, increased grain boundaries, and newly formed interfaces. Meanwhile, the electrical conductivity is improved due to the enhanced carrier mobility, which may originate from the bridging effect between the Bi2Te3 grains and CNTs. The maximum ZT is improved by almost a factor of 2 due to the simultaneous optimization of electrical and thermal performances. Our study demonstrates the superiority of constructing a bulk thermoelectric composite with nanopores by the uniform dispersion of CNTs through a CG technique for enhanced thermoelectric properties, which provides a wider approach to thermoelectric nanostructure engineering.

  13. Study on the local stress induced dislocations on (1 bar 1 bar 1 bar) Te face of CdTe-based crystals

    Science.gov (United States)

    Fu, Xu; Xu, Yadong; Xu, Lingyan; Gu, Yaxu; Jia, Ningbo; Jie, Wanqi

    2017-11-01

    The rosette-like dislocation clusters around Te inclusions in as-grown CdZnTe/CdTe crystals and those introduced by the micro-indentation on CdZnTe/CdTe surface are studied experimentally. The extended dislocation patterns are formed around Te inclusions in both CdZnTe and CdTe crystals, owing to the build-in stress. Two mutually orthogonal tetrahedrons are observed in CdZnTe crystal. However, the ;double-arms; dislocation rosette pattern extended along 〈1 1 0〉 direction is observed in CdTe crystal. The Peierls kink pair mechanism and the Hirsch effects are used to explain the discrepancy of these two different rosette patterns. Similar dislocation rosette patterns are observed on indentation surface of CdZnTe crystal. The dislocation rosette patterns are found to be independent of the indenter orientation, but completely determined by the crystallographic properties of zinc-blende structure of the crystal. Furthermore, the Te(g) and Cd(g) dislocation arms are found to be mixed and bended with each other in CdTe crystal under high indentation stress, making it different from that generated around Te inclusions. A model concerning the comprehensive impact of stress field and electronic polarities dislocations is proposed to clarify the dislocation bending phenomenon.

  14. The magnetic diffusion of neutrons; La diffusion magnetique des neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, W C [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    The purpose of this report is to examine briefly the diffusion of neutrons by substances, particularly by crystals containing permanent atomic or ionic magnetic moments. In other words we shall deal with ferromagnetic, antiferromagnetic, ferrimagnetic or paramagnetic crystals, but first it is necessary to touch on nuclear diffusion of neutrons. We shall start with the interaction of the neutron with a single diffusion centre; the results will then be applied to the magnetic interactions of the neutron with the satellite electrons of the atom; finally we shall discuss the diffusion of neutrons by crystals. (author) [French] Le but de ce rapport est d'examiner, brievement, la diffusion des neutrons par les substances, et surtout, par des cristaux qui contiennent des moments magnetiques atomiques ou ioniques permanents. C'est-a-dire que nous nous interesserons aux cristaux ferromagnetiques, antiferromagnetiques, ferrimagnetiques ou paramagnetiques; il nous faut cependant rappeler d'abord la diffusion nucleaire des neutrons. Nous commencerons par l'interaction du neutron avec un seul centre diffuseur; puis les resultats seront appliques aux interactions magnetiques du neutron avec les electrons satellites de l'atome; enfin nous discuterons la diffusion des neutrons par les cristaux. (auteur)

  15. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)

  16. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2010-01-01

    The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)

  17. β-delayed charged particle decays of neutron-deficient nuclei 20Mg and 23Si and 22Si

    International Nuclear Information System (INIS)

    Babo, Mathieu

    2016-01-01

    The neutron-deficient nuclei 20 Mg, 23 Si and 22 Si were produced by fragmentation at NSCL, at MSU (USA), and implanted into an array of 3 double sided stripped Si detectors, surrounded by 16 high-purity Ge detectors. This novel arrangement allowed the detection of the charged particles emitted by the unbound excited states in coincidence with the γ rays emitted by the de-excitation of the daughter. The βp decay of 20 Mg is very well-known and therefore was used to test and optimize the analysis program. The β-delayed proton transitions to the first 3 excited states in 19 Ne were identified and compared to previous measurements. The half-life, the branching ratio of the transitions and the excitation energies, including the IAS, were measured and are in good agreement with the adopted values. The study of the β+ decay of 23 Si allowed the identification of 14 excited states in 23 Al. The emission of 2 protons from the IAS was unambiguously identified. The measurement of the IAS energy allowed a better determination of the mass excess of 23 Si, giving 23.27 (7) MeV. A possible β3p decay channel was also tentatively identified. Most of the theoretical predictions are in favor of a 2-proton radioactive 22 Si. The β2p decays to the first excited state and the ground state of 20 Na were identified. The branching ratio of the decay to the IAS is 2.05 (44) %, and the IAS excitation energy was measured to be 9040 (54) keV. The additional measurement of the half-life gives T 1/2 = 30.38 (45) ms, and allowed the determination of the partial half-life. In this study, we propose a parameterization of the statistical rate function f for the superallowed Fermi β decays. This allow the first indirect mass measurement of 22 Si ground state, 31.49 (14) MeV. The two-proton threshold is then S2p = 645 (100) keV and does not allow 2p radioactivity. (author) [fr

  18. Neutron polarization

    International Nuclear Information System (INIS)

    Firk, F.W.K.

    1976-01-01

    Some recent experiments involving polarized neutrons are discussed; they demonstrate how polarization studies provide information on fundamental aspects of nuclear structure that cannot be obtained from more traditional neutron studies. Until recently, neutron polarization studies tended to be limited either to very low energies or to restricted regions at higher energies, determined by the kinematics of favorable (p, vector n) and (d, vector n) reactions. With the advent of high intensity pulsed electron and proton accelerators and of beams of vector polarized deuterons, this is no longer the case. One has entered an era in which neutron polarization experiments are now being carried out, in a routine way, throughout the entire range from thermal energies to tens-of-MeV. The significance of neutron polarization studies is illustrated in discussions of a wide variety of experiments that include the measurement of T-invariance in the β-decay of polarized neutrons, a search for the effects of meson exchange currents in the photo-disintegration of the deuteron, the determination of quantum numbers of states in the fission of aligned 235 U and 237 Np induced by polarized neutrons, and the double- and triple-scattering of fast neutrons by light nuclei

  19. On the electronic structure and thermoelectric properties of BiTeBr and BiTeI single crystals and of BiTeI with the addition of BiI3 and CuI

    International Nuclear Information System (INIS)

    Kulbachinskii, Vladimir A.; Kytin, Vladimir G.; Kudryashov, Alexey A.; Kuznetsov, Alexei N.; Shevelkov, Andrei V.

    2012-01-01

    The electronic structures were calculated for BiTeBr and BiTeI using the density-functional theory approach and accounting for the strong spin–orbital interaction. Qualitatively, the band structures for two compounds are similar, showing strong mixing of the p states of all elements in vicinity of the Fermi level, with the band gaps of 0.595 and 0.478 eV for BiTeBr and BiTeI, respectively. The optimized crystal structures show a tendency for the Bi–X (X=Br, I) bond elongation compared to the Bi–Te one. Both compounds are intrinsic n-type semiconductors but display a metallic-like conductivity coupled to rather large thermopower, which is rationalized within the frames of the acoustic phonons scattering model. Because of larger thermopower BiTeBr exhibits a twice higher thermoelectric figure-of-merit near room temperature, ZT=0.17, compared to BiTeI. The addition of 1 mass% of BiI 3 or CuI to BiTeI decreases the mobility of electrons by two orders of magnitude, leading to significantly lower electrical conductivity, but at the same time effectively reduces the thermal conductivity. The prospects of further enhancing the thermoelectric efficiency are briefly discussed. - Graphical abstract: View of the crystal structure of BiTeBr is shown in the figure The optimized crystal structures show a tendency for the Bi–X (X=Br, I) bond elongation compared to the Bi–Te one. The electronic structures were calculated for BiTeBr and BiTeI using the density-functional theory approach and accounting for the strong spin–orbital interaction. Qualitatively, the band structures for two compounds are similar, showing strong mixing of the p states of all elements in vicinity of the Fermi level, with the band gaps of 0.595 and 0.478 eV for BiTeBr and BiTeI, respectively. Both compounds are intrinsic n-type semiconductors but display a metallic-like conductivity coupled to rather large thermopower, which is rationalized within the frames of the acoustic phonons scattering

  20. CdTe and Cd1-xZnxTe for nuclear detectors: facts and fictions

    International Nuclear Information System (INIS)

    Fougeres, P.; Siffert, P.; Hageali, M.; Koebel, J.M.; Regal, R.

    1999-01-01

    Both CdTe and Cd 1-x Zn x Te (CZT) can be considered from their physical properties as very good materials for room temperature X- and γ-rays detection. However, despite years of intense material research, no significant advance has been made to help one to choose between both semiconductors. This paper reviews a few facts about CdTe and CZT to attempt to draw a real comparison between both. THM-CdTe and HPB-CZT have been grown and characterized in Strasbourg. Crystal growth, alloying effects, transport properties and defects are reviewed on the basis of our results and the published ones. The results show that it is still very difficult to claim which one is the best

  1. Identification of Ag-acceptors in $^{111}Ag^{111}Cd$ doped ZnTe and CdTe

    CERN Document Server

    Hamann, J; Deicher, M; Filz, T; Lany, S; Ostheimer, V; Strasser, F; Wolf, H; Wichert, T

    2000-01-01

    Nominally undoped ZnTe and CdTe crystals were implanted with radioactive /sup 111/Ag, which decays to /sup 111/Cd, and investigated by photoluminescence spectroscopy (PL). In ZnTe, the PL lines caused by an acceptor level at 121 meV are observed: the principal bound exciton (PBE) line, the donor-acceptor pair (DAP) band, and the two-hole transition lines. In CdTe, the PBE line and the DAP band that correspond to an acceptor level at 108 meV appear. Since the intensities of all these PL lines decrease in good agreement with the half-life of /sup 111/Ag of 178.8 h, both acceptor levels are concluded to be associated with defects containing a single Ag atom. Therefore, the earlier assignments to substitutional Ag on Zn- and Cd-lattice sites in the respective II-VI semiconductors are confirmed. The assignments in the literature of the S/sub 1/, S /sub 2/, and S/sub 3/ lines in ZnTe and the X/sub 1//sup Ag/, X/sub 2 //sup Ag//C/sub 1//sup Ag/, and C/sub 2//sup Ag/ lines in CdTe to Ag- related defect complexes are ...

  2. Iodine deficiency disorders

    Energy Technology Data Exchange (ETDEWEB)

    Ali, S M [Pakistan Council for Science and Technology, Islamabad (Pakistan)

    1994-12-31

    Iodine deficiency (IDD) is one of the common problem in the diet. Iodine deficiency as prevalence of goiter in population occurs in the mountainous areas. There is consensus that 800 million people are at risk of IDD from living in iodine deficient area and 190 million from goiter. Very high prevalence of IDD in different parts of the world are striking. It has generally observed that in iodine-deficient areas about 50% are affected with goiter, 1-5% from cretinsim and 20% from impaired mental and/or mortor function. (A.B.).

  3. Neutron imaging integrated circuit and method for detecting neutrons

    Science.gov (United States)

    Nagarkar, Vivek V.; More, Mitali J.

    2017-12-05

    The present disclosure provides a neutron imaging detector and a method for detecting neutrons. In one example, a method includes providing a neutron imaging detector including plurality of memory cells and a conversion layer on the memory cells, setting one or more of the memory cells to a first charge state, positioning the neutron imaging detector in a neutron environment for a predetermined time period, and reading a state change at one of the memory cells, and measuring a charge state change at one of the plurality of memory cells from the first charge state to a second charge state less than the first charge state, where the charge state change indicates detection of neutrons at said one of the memory cells.

  4. Skin wound healing in MMP2-deficient and MMP2 / plasminogen double-deficient mice

    DEFF Research Database (Denmark)

    Frøssing, Signe; Rønø, Birgitte; Hald, Andreas

    2010-01-01

    -sensitive MMPs during wound healing. To address whether MMP2 is accountable for the galardin-induced healing deficiency in wildtype and Plg-deficient mice, incisional skin wounds were generated in MMP2 single-deficient mice and in MMP2/Plg double-deficient mice and followed until healed. Alternatively, tissue...... was isolated 7 days post wounding for histological and biochemical analyses. No difference was found in the time from wounding to overt gross restoration of the epidermal surface between MMP2-deficient and wildtype control littermate mice. MMP2/Plg double-deficient mice were viable and fertile, and displayed...... an unchallenged general phenotype resembling that of Plg-deficient mice, including development of rectal prolapses. MMP2/Plg double-deficient mice displayed a slight increase in the wound length throughout the healing period compared with Plg-deficient mice. However, the overall time to complete healing...

  5. Neutron reflector design with Californium 252 neutron for Boron neutron chapter therapy facility using MCNP5 simulation method

    International Nuclear Information System (INIS)

    Muhammad Fakhrurreza; Kusminanto; Y Sardjono

    2014-01-01

    In this research has made a reflector design to provide beams of Neutron for BNCT with Californium-252 radioactive source. This collimator is useful to obtain optimum epithermal neutron flux with the smallest impurity radiation (thermal neutron, fast neutron, and gamma). The design process is done using Monte Carlo N-Particle simulation version 5 (MCNP5) code to calculate the neutron flux tally form. The chosen reflector design is the reflectors which use material such as BeO ceramic with 13 cm thick. Moderator use sulfur material with the slope angle of the cone is 30°. From the calculation result, it is obtained that Reflector with 1 gram Californium-252 source can produce a neutron output thermal which has thermal neutron specification 2.23189 x 10 9 n/s.cm 2 , epithermal neutron 3.51548 x 10 9 n/s.cm 2 , and fast neutron 4.82241 x 10 9 n/s.cm 2 From the result, it needs additional collimator because the BNCT requirement. (author)

  6. Neutron spectometers

    International Nuclear Information System (INIS)

    Poortmans, F.

    1977-01-01

    Experimental work in the field of low-energy neutron physics can be subdivided into two classes: 1)Study of the decay process of the compound-nucleus state as for example the study of the capture gamma rays and of the neutron induced fission process; 2)Study of the reaction mechanism, mainly by measuring the reaction cross-sections and resonance parameters. These neutron cross-sections and resonance parameters are also important data required for many technological applications especially for reactor development programmes. In general, the second class of experiments impose other requirements on the neutron spectrometer than the first class. In most cases, a better neutron energy resolution and a broader neutron energy range are required for the study of the reaction mechanism than for the study of various aspects of the decay process. (author)

  7. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2012-01-01

    The following topics are dealt with: Neutron scattering in contemporary research, neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)

  8. Aerial Neutron Detection: Neutron Signatures for Nonproliferation and Emergency Response Applications

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, Richard J.; Stampahar, Thomas G.; Smith, Ethan X.; Mukhopadhyay, Sanjoy; Wolff, Ronald S.; Rourke, Timothy J.; LeDonne, Jeffrey P.; Avaro, Emanuele; Butler, D. Andre; Borders, Kevin L.; Stampahar, Jezabel; Schuck, William H.; Selfridge, Thomas L.; McKissack, Thomas M.; Duncan, William W.; Hendricks, Thane J.

    2012-10-17

    From 2007 to the present, the Remote Sensing Laboratory has been conducting a series of studies designed to expand our fundamental understanding of aerial neutron detection with the goal of designing an enhanced sensitivity detection system for long range neutron detection. Over 35 hours of aerial measurements in a helicopter were conducted for a variety of neutron emitters such as neutron point sources, a commercial nuclear power reactor, nuclear reactor spent fuel in dry cask storage, depleted uranium hexafluoride and depleted uranium metal. The goals of the project were to increase the detection sensitivity of our instruments such that a 5.4 × 104 neutron/second source could be detected at 100 feet above ground level at a speed of 70 knots and to enhance the long-range detection sensitivity for larger neutron sources, i.e., detection ranges above 1000 feet. In order to increase the sensitivity of aerial neutron detection instruments, it is important to understand the dynamics of the neutron background as a function of altitude. For aerial neutron detection, studies have shown that the neutron background primarily originates from above the aircraft, being produced in the upper atmosphere by galactic cosmic-ray interactions with air molecules. These interactions produce energetic neutrons and charged particles that cascade to the earth’s surface, producing additional neutrons in secondary collisions. Hence, the neutron background increases as a function of altitude which is an impediment to long-range neutron detection. In order to increase the sensitivity for long range detection, it is necessary to maintain a low neutron background as a function of altitude. Initial investigations show the variation in the neutron background can be decreased with the application of a cosmic-ray shield. The results of the studies along with a representative data set are presented.

  9. Study of CdTe:Cl and CdZnTe detectors for medical multi-slices X-ray Computed Tomography; Etude de detecteurs en CdTe:Cl et CdZnTe pour la tomographie X medicale multicoupes

    Energy Technology Data Exchange (ETDEWEB)

    Ricq, St

    1999-09-28

    The application of CdTe and CdZnTe detectors to medical X-ray Computed Tomography have been investigated. Different electrodes (Au, Pt, In) have been deposited on CdZnTe HPBM and on CdTe:ClTHM. Their injection properties have been determined with Current-Voltage characteristics. Under X-ray in CT conditions, injection currents measurements reveal trapped carriers space-charges formation. The same way, the comparisons of the responses to X-beam cut-off with various injection possibilities enable to follow the space-charges evolutions and then to determine the predominant traps types. Nevertheless, both hole and electron traps are responsible for the memory effect e.g. the currents levels dependence with irradiation history. This effect is noticed in particular on responses to fast flux variations that simulate scanner's conditions. Trap levels probably corresponding to native defects are responsible for these limitations. In order to make such detectors suitable for X-ray Computed Tomography, significant progresses in CdTe for CdZnTe crystal growth with an important defects densities reduction (factor 10), or possibly counting mode operation, seem necessary. (author)

  10. Fluctuations in induced charge introduced by Te inclusions within CdZnTe radiation detectors

    International Nuclear Information System (INIS)

    Bale, Derek S.

    2010-01-01

    Recently, homogenization theory based on a multiple-scale perturbation of the electron transport equation has been used to derive a mathematical framework for modeling the excess charge lost to Te inclusions within radiation detectors based on semi-insulating cadmium zinc telluride (CdZnTe). In that theory, the heterogeneous material is mathematically replaced by a homogenized CdZnTe crystal whose effective electron attenuation length incorporates the additional uniform electron trapping caused by the inclusions. In this paper, the homogenization theory is extended to incorporate fluctuations in the induced charge (i.e., charge collection nonuniformities) introduced by the random position and size distributions of a noncorrelated population of small (i.e, <20 μm) Te inclusions. Analysis of the effective parameters derived within the homogenized framework is used to develop a probability distribution of effective electron attenuation lengths, and therefore effective mobility-lifetime products, as a function of both the position and size distribution of Te inclusions. Example distributions are detailed for the case of an exponential size distribution at various number densities. Further, it is demonstrated that the inclusion-induced material nonuniformities derived in this paper can be numerically sampled efficiently, making them applicable to Monte Carlo device simulation of realistic CdZnTe detectors. Simulated charge induction maps and pulse-height spectra are presented and compared to recently published measurements.

  11. Synovectomy by Neutron capture; Sinovectomia por captura de neutrones

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R.; Torres M, C. [Centro Regional de Estudios Nucleares, Universidad Autonoma de Zacatecas, C. Cipres 10, Fracc. La Penuela, 98000 Zacatecas (Mexico)

    1998-12-31

    The Synovectomy by Neutron capture has as purpose the treatment of the rheumatoid arthritis, illness which at present does not have a definitive curing. This therapy requires a neutron source for irradiating the articulation affected. The energy spectra and the intensity of these neutrons are fundamental since these neutrons induce nuclear reactions of capture with Boron-10 inside the articulation and the freely energy of these reactions is transferred at the productive tissue of synovial liquid, annihilating it. In this work it is presented the neutron spectra results obtained with moderator packings of spherical geometry which contains in its center a Pu{sup 239} Be source. The calculations were realized through Monte Carlo method. The moderators assayed were light water, heavy water base and the both combination of them. The spectra obtained, the average energy, the neutron total number by neutron emitted by source, the thermal neutron percentage and the dose equivalent allow us to suggest that the moderator packing more adequate is what has a light water thickness 0.5 cm (radius 2 cm) and 24.5 cm heavy water (radius 26.5 cm). (Author)

  12. Assessing neutron generator output using neutron activation of silicon

    International Nuclear Information System (INIS)

    Kehayias, Pauli M.; Kehayias, Joseph J.

    2007-01-01

    D-T neutron generators are used for elemental composition analysis and medical applications. Often composition is determined by examining elemental ratios in which the knowledge of the neutron flux is unnecessary. However, the absolute value of the neutron flux is required when the generator is used for neutron activation analysis, to study radiation damage to materials, to monitor the operation of the generator, and to measure radiation exposure. We describe a method for absolute neutron output and flux measurements of low output D-T neutron generators using delayed activation of silicon. We irradiated a series of silicon oxide samples with 14.1 MeV neutrons and counted the resulting gamma rays of the 28 Al nucleus with an efficiency-calibrated detector. To minimize the photon self-absorption effects within the samples, we used a zero-thickness extrapolation technique by repeating the measurement with samples of different thicknesses. The neutron flux measured 26 cm away from the tritium target of a Thermo Electron A-325 D-T generator (Thermo Electron Corporation, Colorado Springs, CO) was 6.2 x 10 3 n/s/cm 2 ± 5%, which is consistent with the manufacturer's specifications

  13. Assessing neutron generator output using neutron activation of silicon

    Energy Technology Data Exchange (ETDEWEB)

    Kehayias, Pauli M. [Body Composition Laboratory, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111 (United States); Kehayias, Joseph J. [Body Composition Laboratory, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111 (United States)]. E-mail: joseph.kehayias@tufts.edu

    2007-08-15

    D-T neutron generators are used for elemental composition analysis and medical applications. Often composition is determined by examining elemental ratios in which the knowledge of the neutron flux is unnecessary. However, the absolute value of the neutron flux is required when the generator is used for neutron activation analysis, to study radiation damage to materials, to monitor the operation of the generator, and to measure radiation exposure. We describe a method for absolute neutron output and flux measurements of low output D-T neutron generators using delayed activation of silicon. We irradiated a series of silicon oxide samples with 14.1 MeV neutrons and counted the resulting gamma rays of the {sup 28}Al nucleus with an efficiency-calibrated detector. To minimize the photon self-absorption effects within the samples, we used a zero-thickness extrapolation technique by repeating the measurement with samples of different thicknesses. The neutron flux measured 26 cm away from the tritium target of a Thermo Electron A-325 D-T generator (Thermo Electron Corporation, Colorado Springs, CO) was 6.2 x 10{sup 3} n/s/cm{sup 2} {+-} 5%, which is consistent with the manufacturer's specifications.

  14. Probing Pb+Pb collisions at √sNN = 2.76 TeV with spectator neutrons in AMPT model

    International Nuclear Information System (INIS)

    Mohanty, Bedangadas; Bairathi, Vipul; Haque, Md. Rihan; Chatterjee, Sandeep

    2016-01-01

    In high energy heavy-ion collisions a precise knowledge of the initial state is required in order to describe properties of the strongly interacting medium. There is event by event geometric as well as quantum fluctuations in the initial condition of heavy-ion collisions. The standard technique of analyzing heavy-ion collisions in bins of centrality obtained from final state multiplicity averages out the various initial configurations and thus restricts the study to only a limited range of initial conditions. In this work, we propose an additional binning in terms of total spectator neutrons (L+R), which is sum of left (L) and right (R) going spectator neutrons in an event. This offers us a key control parameter to probe events with broader range of initial conditions providing us an opportunity to investigate events with rarer initial conditions which otherwise get masked when analyzed by centrality binning alone

  15. Hyper-thermal neutron irradiation field for neutron capture therapy

    International Nuclear Information System (INIS)

    Sakurai, Yoshinori; Kobayashi, Tooru; Kanda, Keiji

    1994-01-01

    The utilization of hyper-thermal neutrons, which have an energy spectrum of a Maxwell distribution higher than the room temperature of 300 K, has been studied in order to improve the thermal neutron flux distribution in a living body for a deep-seated tumor in neutron capture therapy (NCT). Simulation calculations using MCNP-V3 were carried out in order to investigate the characteristics of the hyper-thermal neutron irradiation field. From the results of simulation calculations, the following were confirmed: (i) The irradiation field of the hyper-thermal neutrons is feasible by using some scattering materials with high temperature, such as Be, BeO, C, SiC and ZrH 1.7 . Especially, ZrH 1.7 is thought to be the best material because of good characteristics of up-scattering for thermal neutrons. (ii) The ZrH 1.7 of 1200 K yields the hyper-thermal neutrons of a Maxwell-like distribution at about 2000 K and the treatable depth is about 1.5 cm larger comparing with the irradiation of the thermal neutrons of 300 K. (iii) The contamination by the secondary gamma-rays from the scattering materials can be sufficiently eliminated to the tolerance level for NCT through the bismuth layer, without the larger change of the energy spectrum of hyper-thermal neutrons. ((orig.))

  16. Effects of neutron spectrum and external neutron source on neutron multiplication parameters in accelerator-driven system

    International Nuclear Information System (INIS)

    Shahbunder, Hesham; Pyeon, Cheol Ho; Misawa, Tsuyoshi; Lim, Jae-Yong; Shiroya, Seiji

    2010-01-01

    The neutron multiplication parameters: neutron multiplication M, subcritical multiplication factor k s , external source efficiency φ*, play an important role for numerical assessment and reactor power evaluation of an accelerator-driven system (ADS). Those parameters can be evaluated by using the measured reaction rate distribution in the subcritical system. In this study, the experimental verification of this methodology is performed in various ADS cores; with high-energy (100 MeV) proton-tungsten source in hard and soft neutron spectra cores and 14 MeV D-T neutron source in soft spectrum core. The comparison between measured and calculated multiplication parameters reveals a maximum relative difference in the range of 6.6-13.7% that is attributed to the calculation nuclear libraries uncertainty and accuracy for energies higher than 20 MeV and also dependent on the reaction rate distribution position and count rates. The effects of different core neutron spectra and external neutron sources on the neutron multiplication parameters are discussed.

  17. Strong sp-d exchange coupling in ZnMnTe/ZnMgTe core/shell nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Wojnar, Piotr; Janik, Elzbieta; Szymura, Malgorzata; Zaleszczyk, Wojciech; Kret, Slawomir; Klopotowski, Lukasz; Wojciechowski, Tomasz; Baczewski, Lech T.; Wiater, Maciej; Karczewski, Grzegorz; Wojtowicz, Tomasz; Kossut, Jacek [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Suffczynski, Jan; Papierska, Joanna [Institute of Experimental Physics, Warsaw University, ul. Hoza 69, 00-681 Warsaw (Poland)

    2014-07-15

    In this work, our recent progress in the growth and optical studies of telluride nanowire heterostructures containing a small molar fraction of magnetic Mn-ions of only a few percent is overviewed. ZnMnTe/ZnMgTe core/shell nanowires (NWs) are grown by molecular beam epitaxy by employing the vapor-liquid-solid growth mechanism assisted with gold catalyst. The structures are studied by means of photoluminescence and microphotoluminescence in an external magnetic field. In the first step, however, an activation of the near band edge emission from ZnTe and ZnMnTe nanowires is described, which is achieved by coating the nanowires with shells made of ZnMgTe. The role of these shells is to passivate Zn(Mn)Te surface states. The incorporation of Mn ions into the crystalline lattice of ZnMnTe nanowires is manifested as a considerable blue shift of near band edge emission with increasing Mn concentration inside the nanowire cores, which reflects directly the increase of their energy gap. In an external magnetic field the near band edge emission exhibits a giant spectral redshift accompanied by an increase of the circular polarization of the emitted light. Both effect are fingerprints of giant Zeeman splitting of the band edges due to sp-d exchange interaction between the band carriers and magnetic Mn-ions. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Neutron dosimetry at SLAC: Neutron sources and instrumentation

    International Nuclear Information System (INIS)

    Liu, J.C.; Jenkins, T.M.; McCall, R.C.; Ipe, N.E.

    1991-10-01

    This report summarizes in detail the dosimetric characteristics of the five radioisotopic type neutron sources ( 238 PuBe, 252 Cf, 238 PuB, 238 PuF 4 , and 238 PuLi) and the neutron instrumentation (moderated BF 3 detector, Anderson-Braun (AB) detector, AB remmeter, Victoreen 488 Neutron Survey Meter, Beam Shut-Off Ionization Chamber, 12 C plastic scintillator detector, moderated indium foil detector, and moderated and bare TLDs) that are commonly used for neutron dosimetry at the Stanford Linear Accelerator Center (SLAC). 36 refs,. 19 figs

  19. Iodine Deficiency

    NARCIS (Netherlands)

    Zimmermann, M.B.

    2009-01-01

    Iodine deficiency has multiple adverse effects in humans, termed iodine deficiency disorders, due to inadequate thyroid hormone production. Globally, it is estimated that 2 billion individuals have an insufficient iodine intake, and South Asia and sub-Saharan Africa are particularly affected.

  20. The effect of dephasing on edge state transport through p-n junctions in HgTe/CdTe quantum wells.

    Science.gov (United States)

    Zhang, Ying-Tao; Song, Juntao; Sun, Qing-Feng

    2014-02-26

    Using the Landauer-Büttiker formula, we study the effect of dephasing on the transport properties of the HgTe/CdTe p-n junction. It is found that in the HgTe/CdTe p-n junction the topologically protected gapless helical edge states manifest a quantized 2e²/h plateau robust against dephasing, in sharp contrast to the case for the normal HgTe/CdTe quantum well. This robustness of the transport properties of the edge states against dephasing should be attributed to the special construction of the HgTe/CdTe p-n junction, which limits the gapless helical edge states to a very narrow region and thus weakens the influence of the dephasing on the gapless edge states to a large extent. Our results demonstrate that the p-n junction could be a substitute device for use in experimentally observing the robust edge states and quantized plateau. Finally, we present a feasible scheme based on current experimental methods.