WorldWideScience

Sample records for beam lifetime spectroscopy

  1. Lifetime Resolved Fluorescence Fluctuation Spectroscopy

    Science.gov (United States)

    Guo, Peng; Berland, Keith

    2009-11-01

    Fluorescence correlation spectroscopy (FCS) has been widely used investigate molecular dynamics and interactions in biological systems. FCS typically resolves the component species of a sample either through differences in diffusion coefficient or molecular brightness. Diffusion based assays currently have a major limitation which requires that the diffusion coefficients of component species in a sample must be substantially different in order to be resolved. This criterion is not met in many important cases, such as when molecules of similar molecular weight bind to each other. This limitation can be overcome, and resolution of FCS measurements enhanced, by combining FCS measurements with measurements of fluorescence lifetimes. By using of global analysis on simultaneously acquired FCS and lifetime data we show that we can dramatically enhance resolution in FCS measurements, and accurately resolve the concentration and diffusion coefficients of multiple sample components even when their diffusion coefficients are identical provided there is a difference in the lifetime of the component species. We show examples of this technique using both simulations and experiments. It is expected that this method will be of significance for binding assays studying molecular interactions.

  2. Positron annihilation lifetime spectroscopy at a superconducting electron accelerator

    Science.gov (United States)

    Wagner, A.; Anwand, W.; Attallah, A. G.; Dornberg, G.; Elsayed, M.; Enke, D.; Hussein, A. E. M.; Krause-Rehberg, R.; Liedke, M. O.; Potzger, K.; Trinh, T. T.

    2017-01-01

    The Helmholtz-Zentrum Dresden-Rossendorf operates a superconducting linear accelerator for electrons with energies up to 35 MeV and average beam currents up to 1.6 mA. The electron beam is employed for production of several secondary beams including X-rays from bremsstrahlung production, neutrons, and positrons. The secondary positron beam after moderation feeds the Monoenergetic Positron Source (MePS) where positron annihilation lifetime (PALS) and positron annihilation Doppler-broadening experiments in materials science are performed in parallel. The adjustable repetition rate of the continuous-wave electron beams allows matching of the pulse separation to the positron lifetime in the sample under study. The energy of the positron beam can be set between 0.5 keV and 20 keV to perform depth resolved defect spectroscopy and porosity studies especially for thin films.

  3. Measurements of aperture and beam lifetime using movable beam scrapers in Indus-2 electron storage ring

    Science.gov (United States)

    Kumar, Pradeep; Ghodke, A. D.; Karnewar, A. K.; Holikatti, A. C.; Yadav, S.; Puntambekar, T. A.; Singh, G.; Singh, P.

    2013-12-01

    In this paper, the measurements of vertical and horizontal aperture which are available for stable beam motion in Indus-2 at beam energy 2.5 GeV using movable beam scrapers are presented. These beam scrapers are installed in one of the long straight sections in the ring. With the movement of beam scrapers towards the beam centre, the beam lifetime is measured. The beam lifetime data obtained from the movement of vertical and horizontal beam scrapers are analyzed. The contribution of beam loss due to beam-gas scattering (vacuum lifetime) and electron-electron scattering within a beam bunch (Touschek lifetime) is separated from the measured beam lifetime at different positions of the beam scrapers. Vertical and horizontal beam sizes at scrapers location are estimated from the scraper movement towards the beam centre in quantum lifetime limit and their values closely agree with measured value obtained using X-ray diagnostic beamline.

  4. Measurements of aperture and beam lifetime using movable beam scrapers in Indus-2 electron storage ring.

    Science.gov (United States)

    Kumar, Pradeep; Ghodke, A D; Karnewar, A K; Holikatti, A C; Yadav, S; Puntambekar, T A; Singh, G; Singh, P

    2013-12-01

    In this paper, the measurements of vertical and horizontal aperture which are available for stable beam motion in Indus-2 at beam energy 2.5 GeV using movable beam scrapers are presented. These beam scrapers are installed in one of the long straight sections in the ring. With the movement of beam scrapers towards the beam centre, the beam lifetime is measured. The beam lifetime data obtained from the movement of vertical and horizontal beam scrapers are analyzed. The contribution of beam loss due to beam-gas scattering (vacuum lifetime) and electron-electron scattering within a beam bunch (Touschek lifetime) is separated from the measured beam lifetime at different positions of the beam scrapers. Vertical and horizontal beam sizes at scrapers location are estimated from the scraper movement towards the beam centre in quantum lifetime limit and their values closely agree with measured value obtained using X-ray diagnostic beamline.

  5. Active Beam Spectroscopy

    Science.gov (United States)

    von Hellermann, M. G.; Delabie, E.; Jaspers, R. J. E.; Biel, W.; Marchuk, O.; Summers, H. P.; Whiteford, A.; Giroud, C.; Hawkes, N. C.; Zastrow, K. D.

    2008-03-01

    Charge eXchange Recombination Spectroscopy (CXRS) plays a pivotal role in the diagnostics of hot fusion plasmas and is implemented currently in most of the operating devices. In the present report the main features of CXRS are summarized and supporting software packages encompassing "Spectral Analysis Code CXSFIT", "Charge Exchange Analysis Package CHEAP", and finally "Forward Prediction of Spectral Features" are described. Beam Emission Spectroscopy (BES) is proposed as indispensable cross-calibration tool for absolute local impurity density measurements and also for the continuous monitoring of the neutral beam power deposition profile. Finally, a full exploitation of the `Motional Stark Effect' pattern is proposed to deduce local pitch angles, total magnetic fields and possibly radial electric fields. For the proposed active beam spectroscopy diagnostic on ITER comprehensive performance studies have been carried out. Estimates of expected spectral signal-to-noise ratios are based on atomic modelling of neutral beam stopping and emissivities for CXRS, BES and background continuum radiation as well as extrapolations from present CXRS diagnostic systems on JET, Tore Supra, TEXTOR and ASDEX-UG. Supplementary to thermal features a further promising application of CXRS has been proposed recently for ITER, that is a study of slowing-down alpha particles in the energy range up to 2 MeV making use of the 100 keV/amu DNB (Diagnostic Neutral Beam) and the 500 keV/amu HNB (Heating Neutral Beam). Synthetic Fast Ion Slowing-Down spectra are evaluated in terms of source rates and slowing-down parameters

  6. Lifetime obtained by ion beam assisted deposition

    Energy Technology Data Exchange (ETDEWEB)

    Chakaroun, M. [XLIM-MINACOM-UMR 6172, Faculte des Sciences et Techniques, 123 av. Albert Thomas, 87060 Limoges cedex (France); Antony, R. [XLIM-MINACOM-UMR 6172, Faculte des Sciences et Techniques, 123 av. Albert Thomas, 87060 Limoges cedex (France)], E-mail: remi.antony@unilim.fr; Taillepierre, P.; Moliton, A. [XLIM-MINACOM-UMR 6172, Faculte des Sciences et Techniques, 123 av. Albert Thomas, 87060 Limoges cedex (France)

    2007-09-15

    We have fabricated green organic light-emitting diodes based on tris-(8-hydroxyquinoline)aluminium (Alq3) thin films. In order to favor the charge carriers transport from the anode, we have deposited a N,N'-diphenyl-N,N'-bis (3-methylphenyl)-1,1'-diphenyl-4,4'-diamine (TPD) layer (hole transport layer) on a ITO anode. Cathode is obtained with a calcium layer covered with a silver layer. This silver layer is used to protect the other layers against oxygen during the OLED use. All the depositions are performed under vacuum and the devices are not exposed to air during their realisation. In order to improve the silver layer characteristics, we have realized this layer with the ion beam assisted deposition process. The aim of this process is to densify the layer and then reduce the permeation of H{sub 2}O and O{sub 2}. We have used argon ions to assist the silver deposition. All the OLEDs optoelectronic characterizations (I = f(V), L = f(V)) are performed in the ambient air. We compare the results obtained with the assisted layer with those obtained with a classical cathode realized by thermal unassisted evaporation. We have realized lifetime measurements in the ambient air and we discuss about the assisted layer influence on the OLEDs performances.

  7. MULTI-OBJECTIVE ONLINE OPTIMIZATION OF BEAM LIFETIME AT APS

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yipeng

    2017-06-25

    In this paper, online optimization of beam lifetime at the APS (Advanced Photon Source) storage ring is presented. A general genetic algorithm (GA) is developed and employed for some online optimizations in the APS storage ring. Sextupole magnets in 40 sectors of the APS storage ring are employed as variables for the online nonlinear beam dynamics optimization. The algorithm employs several optimization objectives and is designed to run with topup mode or beam current decay mode. Up to 50\\% improvement of beam lifetime is demonstrated, without affecting the transverse beam sizes and other relevant parameters. In some cases, the top-up injection efficiency is also improved.

  8. Photoelectron photoion molecular beam spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Trevor, D.J.

    1980-12-01

    The use of supersonic molecular beams in photoionization mass spectroscopy and photoelectron spectroscopy to assist in the understanding of photoexcitation in the vacuum ultraviolet is described. Rotational relaxation and condensation due to supersonic expansion were shown to offer new possibilities for molecular photoionization studies. Molecular beam photoionization mass spectroscopy has been extended above 21 eV photon energy by the use of Stanford Synchrotron Radiation Laboratory (SSRL) facilities. Design considerations are discussed that have advanced the state-of-the-art in high resolution vuv photoelectron spectroscopy. To extend gas-phase studies to 160 eV photon energy, a windowless vuv-xuv beam line design is proposed.

  9. Electron Beam Lifetime in SPEAR3: Measurement and Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Corbett, J.; Huang, X.; Lee, M.; Lui, P.; /SLAC; Sayyar-Rodsari, B.; /Pavilon Tech., Austin

    2007-12-19

    In this paper we report on electron beam lifetime measurements as a function of scraper position, RF voltage and bunch fill pattern in SPEAR3. We then outline development of an empirical, macroscopic model using the beam-loss rate equation. By identifying the dependence of loss coefficients on accelerator and beam parameters, a numerically-integrating simulator can be constructed to compute beam decay with time. In a companion paper, the simulator is used to train a parametric, non-linear dynamics model for the system [1].

  10. BEAM LIFETIME DEPENDENCE ON THE BEAM-GAS INTERACTIONS IN RHIC.

    Energy Technology Data Exchange (ETDEWEB)

    TRBOJEVIC,D.; HSUEH,H.C.; MACKAY,W.; DREES,A.; FLILLER,R.

    2001-06-18

    In the Relativistic Heavy ion Collider (RHIC) much larger background signals were occurring at BRAMS, one of the four experiments. This was especially pronounced at the time when vacuum conditions deteriorated due to the beam ionization profile monitor replacements. Recording the beam intensities during the store provided the beam lifetime. Predictions from the beam gas interactions to the above measured values are compared The ionization gauges simultaneously recorded the vacuum pressure data.

  11. Positron annihilation lifetime spectroscopy source correction determination: A simulation study

    Science.gov (United States)

    Kanda, Gurmeet S.; Keeble, David J.

    2016-02-01

    Positron annihilation lifetime spectroscopy (PALS) can provide sensitive detection and identification of vacancy-related point defects in materials. These measurements are normally performed using a positron source supported, and enclosed by, a thin foil. Annihilation events from this source arrangement must be quantified and are normally subtracted from the spectrum before analysis of the material lifetime components proceeds. Here simulated PALS spectra reproducing source correction evaluation experiments have been systematically fitted and analysed using the packages PALSfit and MELT. Simulations were performed assuming a single lifetime material, and for a material with two lifetime components. Source correction terms representing a directly deposited source and various foil supported sources were added. It is shown that in principle these source terms can be extracted from suitably designed experiments, but that fitting a number of independent, nominally identical, spectra is recommended.

  12. Application of impedance spectroscopy during the lifetime of organic coatings

    NARCIS (Netherlands)

    Weijde, D.H. van der; Westing, E.P.M. van; Ferrari, G.M.; Wit, J.H.W. de

    1998-01-01

    In this paper the use of Electrochemical Impedance Spectroscopy is evaluated for three situations during the lifetime of organic barrier coating. These situations are: • Defect free coatings • Delaminated, but intact coatings • Coatings with defects combined with cathodic delamination It is shown th

  13. Bessel beam fluorescence lifetime tomography of live embryos (Conference Presentation)

    Science.gov (United States)

    Xu, Dongli; Peng, Leilei

    2016-03-01

    Optical tomography allows isotropic 3D imaging of embryos. Scanning-laser optical tomography (SLOT) has superior light collecting efficiency than wide-field optical tomography, making it ideal for fluorescence imaging of live embryos. We previously reported an imaging system that combines SLOT with a novel Fourier-multiplexed fluorescence lifetime imaging (FmFLIM) technique named FmFLIM-SLOT. FmFLIM-SLOT performs multiplexed FLIM-FRET readout of multiple FRET sensors in live embryos. Here we report a recent effort on improving the spatial resolution of the FmFLIM-SLOT system in order to image complex biochemical processes in live embryos at the cellular level. Optical tomography has to compromise between resolution and the depth of view. In SLOT, the commonly-used focused Gaussian beam diverges quickly from the focal plane, making it impossible to achieve high resolution imaging in a large volume specimen. We thus introduce Bessel beam laser-scanning tomography, which illuminates the sample with a spatial-light-modulator-generated Bessel beam that has an extended focal depth. The Bessel beam is scanned across the whole specimen. Fluorescence projection images are acquired at equal angular intervals as the sample rotates. Reconstruction artifacts due to annular-rings of the Bessel beam are removed by a modified 3D filtered back projection algorithm. Furthermore, in combination of Fourier-multiplexing fluorescence lifetime imaging (FmFLIM) method, the Bessel FmFLIM-SLOT system is capable of perform 3D lifetime imaging of live embryos at cellular resolution. The system is applied to in-vivo imaging of transgenic Zebrafish embryos. Results prove that Bessel FmFLIM-SLOT is a promising imaging method in development biology research.

  14. Beam lifetime measurement and analysis in Indus-2 electron storage ring

    Indian Academy of Sciences (India)

    Pradeep Kumar; A D Ghodke; Gurnam Singh

    2013-05-01

    In this paper, the beam lifetime measurement and its theoretical analysis are presented using measured vacuum pressure and applied radio frequency (RF) cavity voltage in Indus-2 electron storage ring at 2 GeV beam energy. Experimental studies of the effect of RF cavity voltage and bunched beam filling pattern on beam lifetime are also presented. An equation of stable beam current decay is evolved and this equation closely follows the observed beam current decay pattern. It shows that the beam is stable and the beam current decay is due to the beam–residual gas interaction (vacuum lifetime) and electron–electron interaction within a bunch (Touschek lifetime). The estimated vacuum, Touschek and total beam lifetimes from analytical formulations are also compared with the measured beam lifetime.

  15. Active beam spectroscopy for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Von Hellermann, M.; Giroud, C.; Jaspers, R. [Association Euratom-Fom, FOM Institute for Plasma Physics Rijnhuizen, Trilateral Euregio Cluster (Netherlands); Hawkes, N.C.; Mullane, M.O.; Zastrow, K.D. [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon (United Kingdom); Krasilnikov, A.; Tugarinov, S. [SRC RF TRINITI, Troitsk, Moscow region (Russian Federation); Lotte, P. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; McKee, G. [Wisconsin Univ., Madison, WI (United States); Malaquias, A. [Associacao EURATOM/IST, Instituto Superior Tecnico, Lisboa (Portugal); Rachlew, E. [Kungliga Tekniska Hoegskolan (KTH), Stockholm(Sweden)

    2003-07-01

    The latest status of 'Active Beam' related spectroscopy aspects as part of the ITER diagnostic scenario is presented. A key issue of the proposed scheme is based on the concept that in order to achieve the ultimate goal of global data consistency, all particles involved, that is, intrinsic and seeded impurity ions as well as helium ash ions and bulk plasma ions and also the plasma background data (e.g. magnetic and electric fields, electron density and temperature profiles) need to be addressed. A further sensible step in this direction is the decision of exploiting both a dedicated low-energy, low-power diagnostic beam (DNB, 2.2 MW 100 keV/amu) as well as the high-power, high-energy heating beams (HNB, 17 MW 500 keV/amu) for maximum diagnostic information. The authors report some new aspects referring to the use of DNB for motional Stark effect (MSE) where the main idea is to treat both beams (HNB and DNB) as potential diagnostic tools with complementary roles. The equatorial ports for the DNB promise excellent spatial resolution, however, the angles are less favourable for a polarimetric MSE exploitation. HNB can be used as probe beam for diagnosing slowing-down fusion alpha with a birth energy of 3,5 MeV.

  16. Preservation of beam loss induced quenches, beam lifetime and beam loss measurements with the HERAp beam-loss-monitor system

    Science.gov (United States)

    Wittenburg, Kay

    1994-06-01

    The beam-loss-monitors (BLMs) in the HERA-proton-ring (HERAp) must fulfill the following requirements: They have to measure losses sensitive and fast enough to prevent the superconducting magnets from beam loss induced quenching; the dynamic range of the monitors must exceed several decades in order to measure losses during beam lifetimes of hundreds of hours as well as the much stronger losses that may quench superconducting magnets; they have to be insensitive to the synchrotron radiation of the adjacent electron-ring (HERAe); and their radiation hardness must allow a monitor-lifetime of a few years of HERA operation. These requirements are well satisfied by the HERAp-BLM-System.

  17. Active beam spectroscopy for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Hellermann, M.G. von, E-mail: mgvh@jet.u [FOM Institute Rijnhuizen, Euratom Association, 3430BE Nieuwegein (Netherlands); Barnsley, R. [ITER Organization, 13108 St.-Paul-Lez-Durance, Cadarache (France); Biel, W. [Institut fuer Energieforschung, Plasmaphysik, Forschungszentrum Juelich, Euratom Association, 52425 Juelich (Germany); Delabie, E. [FOM Institute Rijnhuizen, Euratom Association, 3430BE Nieuwegein (Netherlands); Hawkes, N. [Culham Centre for Fusion Energy, Euratom Association, Culham OX14 3DB (United Kingdom); Jaspers, R. [FOM Institute Rijnhuizen, Euratom Association, 3430BE Nieuwegein (Netherlands); Johnson, D. [Princeton Plasma Physics Laboratory, Princeton, NJ-08548 (United States); Klinkhamer, F. [TNO Science and Industry, Stieltjesweg 1, 2628CK Delft (Netherlands); Lischtschenko, O. [FOM Institute Rijnhuizen, Euratom Association, 3430BE Nieuwegein (Netherlands); Marchuk, O. [Institut fuer Energieforschung, Plasmaphysik, Forschungszentrum Juelich, Euratom Association, 52425 Juelich (Germany); Schunke, B. [ITER Organization, 13108 St.-Paul-Lez-Durance, Cadarache (France); Singh, M.J. [Institute for Plasma Research, Bhat, Gandhinagar, Gurajat 384828 (India); Snijders, B. [TNO Science and Industry, Stieltjesweg 1, 2628CK Delft (Netherlands); Summers, H.P. [Culham Centre for Fusion Energy, Euratom Association, Culham OX14 3DB (United Kingdom); Thomas, D. [ITER Organization, 13108 St.-Paul-Lez-Durance, Cadarache (France); Tugarinov, S. [TRINITI Troitsk, Moscow Region 142092 (Russian Federation); Vasu, P. [Institute for Plasma Research, Bhat, Gandhinagar, Gurajat 384828 (India)

    2010-11-11

    Since the first feasibility studies of active beam spectroscopy on ITER in 1995 the proposed diagnostic has developed into a well advanced and mature system. Substantial progress has been achieved on the physics side including comprehensive performance studies based on an advanced predictive code, which simulates active and passive features of the expected spectral ranges. The simulation has enabled detailed specifications for an optimized instrumentation and has helped to specify suitable diagnostic neutral beam parameters. Four ITER partners share presently the task of developing a suite of ITER active beam diagnostics, which make use of the two 0.5 MeV/amu 18 MW heating neutral beams and a dedicated 0.1 MeV/amu, 3.6 MW diagnostic neutral beam. The IN ITER team is responsible for the DNB development and also for beam physics related aspects of the diagnostic. The RF will be responsible for edge CXRS system covering the outer region of the plasma (1>r/a>0.4) using an equatorial observation port, and the EU will develop the core CXRS system for the very core (0

  18. Evaluation of actinic cheilitis using fluorescence lifetime spectroscopy

    Science.gov (United States)

    Saito Nogueira, Marcelo; Cosci, Alessandro; Pratavieira, Sebastião.; Takahama, Ademar; Souza Azevedo, Rebeca; Kurachi, Cristina

    2016-03-01

    Actinic cheilitis is a potentially malignant disorder that mostly affects the vermilion border of the lower lip and can lead to squamous cell carcinoma. Because of its heterogeneous clinical aspect, it is difficult to indicate representative biopsy area. Late diagnosis is a limiting factor of therapeutic possibilities available to treat oral cancer. The diagnosis of actinic cheilitis is mainly based on clinical and histopathological analysis and it is a time consuming procedure to get the results. Information about the organization and chemical composition of the tissues can be obtained using fluorescence lifetime spectroscopy techniques without the need for biopsy. The main targeted fluorophores are NADH (nicotinamide adenine dinucleotide) and FAD (flavin adenine dinucleotide), which have free and bound states, each one with different average lifetimes. The average lifetimes for free and bound NADH and FAD change according to tissue metabolic alterations and allow a quick and non-invasive clinical investigation of injuries and to help clinicians with the early diagnosis of actinic cheilitis. This study aims to evaluate the fluorescence lifetime parameters at the discrimination of three degrees of epithelial dysplasia, the most important predictor of malignant development, described in up to 100% of actinic cheilitis cases.

  19. Plunger lifetime measurements after Coulomb excitation at intermediate beam energies

    Energy Technology Data Exchange (ETDEWEB)

    Hackstein, Matthias; Dewald, Alfred; Fransen, Christoph; Ilie, Gabriela; Jolie, Jan; Melon, Barbara; Pissulla, Thomas; Rother, Wolfram; Zell, Karl-Oskar [University of Cologne (Germany); Petkov, Pavel [University of Cologne (Germany); INRNE (Bulgaria); Chester, Aaron; Adrich, Przemyslaw; Bazin, Daniel; Bowen, Matt; Gade, Alexandra; Glasmacher, Thomas; Miller, Dave; Moeller, Victoria; Starosta, Krzysztof; Stolz, Andreas; Vaman, Constantin; Voss, Philip; Weissharr, Dirk [Michigan State Univerity (United States); Moeller, Oliver [TU Darmstadt (Germany)

    2008-07-01

    Two recoil-distance-doppler-shift (RDDS) experiments were performed at the NSCL/MSU using Coulomb excitations of the projectile nuclei {sup 110}Pd, {sup 114}Pd at beam energies of 54 MeV/u in order to investigate the evolution of deformation of neutron rich paladium isotopes. The experimental set-up consisted of a dedicated plunger device, developed at the University of Cologne, the SEGA Ge-array and the S800 spectrometer. Lifetimes of the 2{sub 1}{sup +}-states in {sup 110}Pd and {sup 114}Pd were derived from the analysis of the {gamma}-line-shapes as well as from the measured decay-curves. Special features of the data analysis, e.g. features originating from the very high recoil velocities, are discussed.

  20. Benchmarking of Touschek Beam Lifetime Calculations for the Advanced Photon Source

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, A.; Yang, B.

    2017-06-25

    Particle loss from Touschek scattering is one of the most significant issues faced by present and future synchrotron light source storage rings. For example, the predicted, Touschek-dominated beam lifetime for the Advanced Photon Source (APS) Upgrade lattice in 48-bunch, 200-mA timing mode is only ∼ 2 h. In order to understand the reliability of the predicted lifetime, a series of measurements with various beam parameters was performed on the present APS storage ring. This paper first describes the entire process of beam lifetime measurement, then compares measured lifetime with the calculated one by applying the measured beam parameters. The results show very good agreement.

  1. Laser spectroscopy of the antiprotonic helium atom – its energy levels and state lifetimes

    CERN Document Server

    Hidetoshi, Yamaguchi

    2003-01-01

    The antiprotonic atom is a three-body exotic system consisting of an antiproton, an electron and a helium nucleus. Its surprising longevity was found and has been studied for more than 10 years. In this work, transition energies and lifetimes of this exotic atom were systematically studied by using the antiproton beam of AD(Antiproton Decelerator) facility at CERN, with an RFQ antiproton decelerator, a narrow-bandwidth laser, Cerenkov counters with fast-response photomultiplier tubes, and cryogenic helium target systems. Thirteen transition energies were determined with precisions of better than 200 ppb by a laser spectroscopy method, together with the elimination of the shift effect caused by collisions with surrounding atoms. Fifteen lifetimes (decay rates) of short-lived states were determined from the time distributions of the antiproton-annihilation signals and the resonance widths of the atomic spectral lines. The relation between the magnitude of the decay rates and the transition multipolarity was inv...

  2. Lifetime measurements and decay spectroscopy of 132I

    Directory of Open Access Journals (Sweden)

    Bhattacharyya S.

    2014-03-01

    Full Text Available The low-lying states of odd-odd 132I, the 3p-3h nucleus with respect to the doubly magic 132Sn, have been characterized from decay spectroscopy. The neutron rich Iodine and Tellurium isotopes have been produced as fission product of alpha-induced fission of 235U and radiochemically separated. The life-time of the first excited state of 132I have been precisely measured using LaBr3(Ce scintillators from the decay of 132Te. The IT decay of the high spin isomer (8- in 132I has been measured with a Low Energy Photon Spectrometer (LEPS of segmented planar Ge detector.

  3. Fluorescence lifetime spectroscopy for breast cancer margins assessment

    Science.gov (United States)

    Gorpas, Dimitris; Fatakdawala, Hussain; Zhang, Yanhong; Bold, Richard; Marcu, Laura

    2015-03-01

    During breast conserving surgery (BCS), which is the preferred approach to treat most early stage breast cancers, the surgeon attempts to excise the tumor volume, surrounded by thin margin of normal tissue. The intra-operative assessment of cancerous areas is a challenging procedure, with the surgeon usually relying on visual or tactile guidance. This study evaluates whether time-resolved fluorescence spectroscopy (TRFS) presents the potential to address this problem. Point TRFS measurements were obtained from 19 fresh tissue slices (7 patients) and parameters that characterize the transient signals were quantified via constrained least squares deconvolution scheme. Fibrotic tissue (FT, n=69), adipose tissue (AT, n=76), and invasive ductal carcinoma (IDC, n=27) were identified in histology and univariate statistical analysis, followed by multi-comparison test, was applied to the corresponding lifetime data. Significant differentiation between the three tissue types exists at 390 nm and 500 nm bands. The average lifetime is 3.23+/-0.74 ns for AT, 4.21+/-0.83 ns for FT and 4.71+/-0.35 ns (ptissue in real-time and assess tumor margins.

  4. The radiation measurement applied to beam lifetime study on the synchrotron radiation facilities

    Science.gov (United States)

    Li, Yuxiong; Li, Juexin; Liu, Zuping; Cui, Yonggang; Gong, Guanghua; Shao, Beibei

    2003-06-01

    To collect beam loss information from an accelerator radiation field is helpful to machine study and operation. For a synchrotron radiation storage ring, shower electrons give a distinct clue to loss location and a BLM-XS model detector is suitable to detect them. Recently, we set up a new beam loss monitoring system by this method for National Synchrotron Radiation Laboratory (NSRL) storage ring. It does not interfere with the vacuum chamber and machine operation. Different from other systems, the detectors are used in pairs, fixed on opposite sides of the chamber separately. Some interesting phenomena about beam lifetime were observed. We located exactly where an excessive beam loss took place during ramping process and solved the problem. It was proved that gas accumulated at the front ends of photo-beam lines strongly impacted the electron beam and led to beam lifetime decreases. The cause of beam lifetime decrease because of superconducting wiggler is discussed.

  5. BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

    Science.gov (United States)

    Bonomo, F.; Ruf, B.; Barbisan, M.; Cristofaro, S.; Schiesko, L.; Fantz, U.; Franzen, P.; Pasqualotto, R.; Riedl, R.; Serianni, G.; Wünderlich, D.

    2015-04-01

    The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the Hα light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of Hα spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

  6. CO sub 2 absorption of perovskites as seen by positron lifetime spectroscopy

    CERN Document Server

    Suevegh, K; Juhasz, G; Homonnay, Z; Vertes, A

    2000-01-01

    The CO sub 2 absorption of several ABO sub 3 type perovskites was studied by positron lifetime spectroscopy. The longer positron lifetime was associated with positrons trapped by A site vacancies. The evaluated positron lifetime data indicated the relative stability of the crystal structure of Sr(Co sub 0 sub . sub 5 Fe sub 0 sub . sub 5)O sub 3 sub - subdelta against Ca doping at low Ca concentrations. Oxygen desorption and CO sub 2 absorption/desorption could also be followed by positron lifetime spectroscopy. It was shown that the concentration of oxygen vacancies has a large effect on positron lifetime data through the electron density of A site vacancies.

  7. Chiral specific electron vortex beam spectroscopy

    CERN Document Server

    Yuan, J; Babiker, M

    2013-01-01

    Electron vortex beams carry well-defined orbital angular momentum (OAM) about the propagation axis. Such beams are thus characterised by chirality features which make them potentially useful as probes of magnetic and other chiral materials. An analysis of the inelastic processes in which electron vortex beams interact with atoms and which involve OAM exchange is outlined, leading to the multipolar selection rules governing this chiral specific electron vortex beam spectroscopy. Our results show clearly that the selection rules are dependent on the dynamical state and location of the atoms involved. In the most favorable scenario, this form of electron spectroscopy can induce magnetic sublevel transitions which are commonly probed using circularly polarized photon beams.

  8. Role of electron-ion recombination processes in the lifetime of stored D{sup +} beams

    Energy Technology Data Exchange (ETDEWEB)

    Gao, H.; Justiniano, E.; Asp, S.; Danared, H.; DeWitt, D.R.; Schuch, R. [Department of Atomic Physics, Stockholm University, S-104 05 Stockholm (Sweden)]|[Manne Siegbahn Laboratory, Stockholm University, S-104 05 Stockholm (Sweden)

    1996-10-01

    We have studied spontaneous electron-ion recombination processes taking place in the electron cooler of a storage ring by a systematic investigation of the lifetimes of a stored beam for several choices of the cooler electron beam density. The measurements were performed with 8- and 21-MeV/amu D{sup +} and, in this case, it is found that the main contributor to the beam lifetime is radiative recombination. Contributions to the lifetime from other processes such as three-body recombination and single elastic scattering are examined. {copyright} {ital 1996 The American Physical Society.}

  9. BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Bonomo, F., E-mail: federica.bonomo@igi.cnr.it [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Istituto Gas Ionizzati - CNR, Corso Stati Uniti 4, 35127 Padova (Italy); Ruf, B.; Schiesko, L.; Fantz, U.; Franzen, P.; Riedl, R.; Wünderlich, D. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Barbisan, M.; Pasqualotto, R.; Serianni, G. [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Cristofaro, S. [Universitá degli Studi di Padova, Via 8 Febbraio 2, 35122 Padova (Italy)

    2015-04-08

    The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (< 0.4 °) together with a low source pressure (≤ 0.3 Pa) would permit to reduce the ion losses along the beamline, keeping the stripping particle losses below 30%. However, the attainment of such beam properties is not straightforward. At IPP, the negative ion source testbed BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the H{sub α} light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of H{sub α} spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

  10. Relativistic atomic beam spectroscopy II

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1991-12-31

    We are requesting support for a postdoctoral person to participate in H{sup -} studies at Los Alamos. In addition, we are requesting funding for a state-of-the-art YAG laser system that would allow us to obtain data at three times our present rate with improved beam quality.

  11. Positron annihilation lifetime spectroscopy study of roller burnished magnesium alloy

    Directory of Open Access Journals (Sweden)

    Zaleski Radosław

    2015-12-01

    Full Text Available The effect of roller burnishing on Vickers’ hardness and positron lifetimes in the AZ91HP magnesium alloy was studied. The microhardness increases with an increase in the burnishing force and with a decrease in the feed. The comparison of various methods of analysis of positron annihilation lifetime (PAL spectra allowed identification of two components, which are related to solute-vacancy complexes and vacancy clusters, respectively. It was found that the increase in microhardness was related to the increase in the concentration of vacancy clusters.

  12. Lifetime spectroscopy a method of defect characterization in silicon for photovoltaic applications

    CERN Document Server

    Rein, Stefan

    2005-01-01

    Lifetime spectroscopy is one of the most sensitive diagnostic tools for the identification and analysis of impurities in semiconductors. Since it is based on the recombination process, it provides insight into precisely those defects that are relevant to semiconductor devices such as solar cells. This book introduces a transparent modeling procedure that allows a detailed theoretical evaluation of the spectroscopic potential of the different lifetime spectroscopic techniques. The various theoretical predictions are verified experimentally with the context of a comprehensive study on different metal impurities. The quality and consistency of the spectroscopic results, as explained here, confirms the excellent performance of lifetime spectroscopy.

  13. Lifetime

    Institute of Scientific and Technical Information of China (English)

    姚祎

    2004-01-01

    @@ 继ESPN刊出同名杂志之后,2003年赫斯特公司(Hearst Corp.)和迪斯尼(Walt Disney Co.)的合作促成了一本新杂志的诞生:(Lifetime),其目标读者是成百万收看同名有线电视网节目的妇女们.

  14. Degradation of encapsulants for photovoltaic modules made of ethylene vinyl acetate studied by positron annihilation lifetime spectroscopy

    Science.gov (United States)

    Hagihara, Hideaki; Kunioka, Masao; Suda, Hiroyuki; Hara, Yukiko; Masuda, Atsushi

    2016-10-01

    The structure of ethylene vinyl acetate (EVA) encapsulants of crystalline-Si photovoltaic modules after the damp heat (DH) test was evaluated by positron annihilation lifetime spectroscopy (PALS). A reduction in free-volume hole size, which indicates the progress of deacetylation, was observed after the DH test. The difference in lifetime (Δτ) between the initial and DH-tested samples clearly increased after the DH test for 3000 h. The increase in Δτ was correlated with the acetic acid concentration in the EVA estimated by ion chromatography. The depth profile analysis by slow positron beam PALS revealed that Δτ in the near-surface region of the Si-cell side was significantly larger than that of the cover-glass side. This result indicates that deacetylation near the Si cell/EVA interface is accelerated.

  15. Analytical estimation of the beam-beam interaction limited dynamic apertures and lifetimes in e{sup +}e{sup -} circular colliders

    Energy Technology Data Exchange (ETDEWEB)

    Gao, J

    2000-12-01

    Physically speaking, the delta function like beam-beam nonlinear forces at interaction points (IPs) act as a sum of delta function nonlinear multipoles. By applying the general theory established in ref. [1], in this paper we investigate analytically the beam-beam interaction limited dynamic apertures and the corresponding beam lifetimes for both the round and the flat beams. Relations between the beam-beam limited beam lifetimes and the beam-beam tune shifts are established, which show clearly why experimentally one has always a maximum beam-beam tune shift, {zeta}{sub y,max}, around 0.045 for e{sup +}e{sup -} circular colliders, and why one can use round beams to double this value approximately. Comparisons with some machine parameters are given. Finally, we discuss the mechanism of the luminosity reduction due to a definite collision crossing angle. (author)

  16. Nanoscopic properties of silica filled polydimethylsiloxane by means of positron annihilation lifetime spectroscopy

    DEFF Research Database (Denmark)

    Wiinberg, P.; Eldrup, Morten Mostgaard; Maurer, F.H.J.

    2004-01-01

    Positron annihilation lifetime spectroscopy (PALS) was performed on a series of polydimethylsiloxane (PDMS)/fumed silicon dioxide (SiO2) composites at temperatures between -185 and 100degreesC to study the effect of filler content and filler particle size on the free volume properties and the pos......Positron annihilation lifetime spectroscopy (PALS) was performed on a series of polydimethylsiloxane (PDMS)/fumed silicon dioxide (SiO2) composites at temperatures between -185 and 100degreesC to study the effect of filler content and filler particle size on the free volume properties...

  17. Applications of beam-foil spectroscopy to atomic collisions in solids

    Science.gov (United States)

    Sellin, I. A.

    1976-01-01

    Some selected papers presented at the Fourth International Conference on Beam-Foil Spectroscopy, whose results are of particular pertinence to ionic collision phenomena in solids, are reviewed. The topics discussed include solid target effects and means of surmounting them in the measurement of excited projectile ion lifetimes for low-energy heavy element ions; the electron emission accompanying the passage of heavy particles through solid targets; the collision broadening of X rays emitted from 100 keV ions moving in solids; residual K-shell excitation in chlorine ions penetrating carbon; comparison between 40 MeV Si on gaseous SiH4 targets at 300 mtorr and 40 MeV Si on Al; and the emergent surface interaction in beam-foil spectroscopy. A distinct overlap of interests between the sciences of beam-foil spectroscopy and atomic collisions in solids is pointed out.

  18. Assessing the photoaging process at sun exposed and non-exposed skin using fluorescence lifetime spectroscopy

    Science.gov (United States)

    Saito Nogueira, Marcelo; Kurachi, Cristina

    2016-03-01

    Photoaging is the skin premature aging due to exposure to ultraviolet light, which damage the collagen, elastin and can induce alterations on the skin cells DNA, and, then, it may evolve to precancerous lesions, which are widely investigated by fluorescence spectroscopy and lifetime. The fluorescence spectra and fluorescence lifetime analysis has been presented as a technique of great potential for biological tissue characterization at optical diagnostics. The main targeted fluorophores are NADH (nicotinamide adenine dinucleotide) and FAD (flavin adenine dinucleotide), which have free and bound states, each one with different average lifetimes. The average lifetimes for free and bound NADH and FAD change according to tissue metabolic alterations and may contribute to a non-invasive clinical investigation of injuries such as skin lesions. These lesions and the possible areas where they may develop can be interrogated using fluorescence lifetime spectroscopy taking into account the variability of skin phototypes and the changes related to melanin, collagen and elastin, endogenous fluorophores which have emissions that spectrally overlap to the NADH and FAD emission. The objective of this study is to assess the variation on fluorescence lifetimes of normal skin at sun exposed and non-exposed areas and associate this variation to the photoaging process.

  19. Advances in Contactless Silicon Defect and Impurity Diagnostics Based on Lifetime Spectroscopy and Infrared Imaging

    Directory of Open Access Journals (Sweden)

    Jan Schmidt

    2007-01-01

    Full Text Available This paper gives a review of some recent developments in the field of contactless silicon wafer characterization techniques based on lifetime spectroscopy and infrared imaging. In the first part of the contribution, we outline the status of different lifetime spectroscopy approaches suitable for the identification of impurities in silicon and discuss—in more detail—the technique of temperature- and injection-dependent lifetime spectroscopy. The second part of the paper focuses on the application of infrared cameras to analyze spatial inhomogeneities in silicon wafers. By measuring the infrared signal absorbed or emitted from light-generated free excess carriers, high-resolution recombination lifetime mappings can be generated within seconds to minutes. In addition, mappings of non-recombination-active trapping centers can be deduced from injection-dependent infrared lifetime images. The trap density has been demonstrated to be an important additional parameter in the characterization and assessment of solar-grade multicrystalline silicon wafers, as areas of increased trap density tend to deteriorate during solar cell processing.

  20. Charge-exchange cross sections and beam lifetimes for stored and decelerated bare uranium ions

    Energy Technology Data Exchange (ETDEWEB)

    Stoehlker, T. [Frankfurt Univ. (Germany). Inst. fuer Kernphysik]|[Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Ludziejewski, T.; Reich, H.; Bosch, F.; Franzke, B.; Kozhuharov, C.; Menzel, G.; Mokler, P.H.; Nolden, F.; Steck, M. [Frankfurt Univ. (Germany). Inst. fuer Kernphysik; Dunford, R.W. [Argonne National Lab., IL (United States). Physics Div.; Eichler, J. [Hahn-Meitner-Institut Berlin GmbH (Germany). Bereich Theoretische Physik]|[Freie Univ. Berlin (Germany). Fachbereich Physik; Rymuza, P. [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland); Stachura, Z. [Institute of Nuclear Physics, Cracow (Poland); Swiat, P.; Warczak, A. [Uniwersytet Jagiellonski, Cracow (Poland). Inst. Fizyki; Winkler, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)

    1998-08-01

    Charge-exchange cross sections and beam lifetimes are studied for decelerated bare uranium ions at the ESR storage ring. By deceleration from the initial energy of 358 MeV/u down to various energies as low as 49 MeV/u, i.e. far below the production energy of bare ionic species, the electron pick-up cross sections were obtained for collisions with N{sub 2}, Ar, CH{sub 4} and Kr gaseous targets. The measured cross sections and beam lifetimes are compared with the theoretical results for radiative and non-radiative electron capture. The present data along with the theoretical approximations discussed, provide a solid basis for the estimation of beam lifetimes for decelerated bare high-Z ions. Moreover, a normalization procedure is proposed, in which absolute total charge-exchange cross sections are derived by normalizing the simultaneously measured yield of K-REC photons to rigorously calculated relativistic cross sections. This method along with the unprecedented beam conditions at the ESR storage ring, allows a significant improvement in the accuracy of cross section data. (orig.)

  1. Sulfonated polyetherketone (SPEK-C) films investigated by positron annihilation lifetime spectroscopy and atomic force microscopy

    Institute of Scientific and Technical Information of China (English)

    Htwe Htwe Yin; YIN Ze-Jie; TANG Shi-Biao; HUANG Huan; ZHU Da-Ming

    2005-01-01

    The characterization of sulfonated polyetherketone (SPEK-C) films was investigated by using positron annihilation lifetime spectroscopy (PALS) and atomic force microscopy (AFM). It was found that free volume radius and intensity depend on the variation of sulfonation degree and solvent evaporation time of the films. Pore size and distribution determined from PALS and AFM measurements showed reasonable agreement.

  2. Study of positron annihilation lifetime spectroscopy in carbon black-filled HDPE composite

    CERN Document Server

    Zhang Xian Feng; Zhou Xian Yi; Weng Hu Imin; Ye Bang Jiao; Han Rong Dian; Jia Shao Jin; Zhang Zhi Cheng

    2002-01-01

    The variation of the electrical conductivity of high density polyethylene (HDPE) with the carbon black (CB) content was studied using positron annihilation lifetime spectroscopy (PALS) and free-volume model, the crystallinity of HDPE/CB composite and 'percolation' effect were discussed with measurements of conductivity and DSC test

  3. The study of synthetic food dyes by positron annihilation lifetime spectroscopy.

    Science.gov (United States)

    Pivtsaev, A. A.; Razov, V. I.

    2015-06-01

    By method of positron annihilation lifetime spectroscopy (PALS), substances are food dyes were studied: E-102 (Tartrazine), E-124 (Ponso 4R), E 132 (Indigo carmine), E-133 (Brilliant Blue), E-151 (Black Shiny). They are examined for the presence of carcinogenic properties. The difference between dyes having explicit carcinogenic properties and mutagenic properties (non-explicit carcinogens) is established.

  4. Spectroscopy with Hadrons Beams at COMPASS

    CERN Document Server

    CERN. Geneva

    2007-01-01

    Following numerous interactions with the SPSC in 2007 we review projected capa- bilities of the COMPASS spectrometer in the field of light hadron spectroscopy. The paper describes in detail a full simulation with subsequent partial wave analysis of two final states for central production. Both, neutral and all charged states can very well be observed and analyzed within COMPASS. In addition we show the result of a full partial wave analysis of data taken in the pilot run 2004 using the diffractively produced $\\pi^+\\pi^-\\pi^-$ final state. The results agree remarkably well with previous data taken an BNL. We also vaticinate the physics data sample expected for 2008, using projected beam times for different reaction mechanisms.

  5. Applications and advances of positron beam spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Howell, R., LLNL

    1998-03-18

    Over 50 scientists from DOE-DP, DOE-ER, the national laboratories, academia and industry attended a workshop held on November 5-7, 1997 at Lawrence Livermore National Laboratory. Workshop participants were charged to address two questions: Is there a need for a national center for materials analysis using positron techniques and can the capabilities at Lawrence Livermore National Laboratory serve this need. To demonstrate the need for a national center, the workshop participants discussed the technical advantages enabled by high positron currents and advanced measurement techniques, the role that these techniques would play in materials analysis and the demand for the data. Livermore now leads the world in materials analysis capabilities by positrons due to developments in response to demands of stockpile stewardship. The Livermore facilities now include the world`s highest current beam of keV positrons, a scanning pulsed positron microprobe under development capable of three dimensional maps of defect size and concentration, an MeV positron beam for defect analysis of large samples, and electron momentum spectroscopy by positrons. It was concluded that the positron microprobe under development at LLNL and other new instruments that would be relocated at LLNL at the high current keV source are an exciting step forward in providing results for the positron technique. These new data will impact a wide variety of applications.

  6. Decay Lifetimes of the Vector and Tensor Polarization of a Stored Deuteron Beam

    CERN Document Server

    Mane, S R

    2015-01-01

    An rf solenoid was operated in the IUCF Cooler to induce a depolarizing spin resonance for a stored polarized deuteron beam. The decay lifetimes of the vector and tensor polarizations were found to be in the ratio $1.9:1$, as opposed to the expected ratio of $3:1$ from standard angular momentum theory. This report describes my investigations and attempts to formulate a theoretical explanation of the above phenomenon.

  7. Optimized frequency dependent photothermal beam deflection spectroscopy

    Science.gov (United States)

    Korte, D.; Cabrera, H.; Toro, J.; Grima, P.; Leal, C.; Villabona, A.; Franko, M.

    2016-12-01

    In the letter the optimization of the experimental setup for photothermal beam deflection spectroscopy is performed by analyzing the influence of its geometrical parameters (detector and sample position, probe beam radius and its waist position etc) on the detected signal. Furthermore, the effects of the fluid’s thermo-optical properties, for optimized geometrical configuration, on the measurement sensitivity and uncertainty determination of sample thermal properties is also studied. The examined sample is a recently developed CuFeInTe3 material. It is seen from the obtained results, that it is a complex problem to choose the proper geometrical configuration as well as sensing fluid to enhance the sensitivity of the method. A signal enhancement is observed at low modulation frequencies by placing the sample in acetonitrile (ACN), while at high modulation frequencies the sensitivity is higher for measurements made in air. For both, detection in air and acetonitrile the determination of CuFeInTe3 thermal properties is performed. The determined values of thermal diffusivity and thermal conductivity are (0.048  ±  0.002)  ×  10-4 m2 s-1 and 4.6  ±  0.2 W m-1 K-1 and (0.056  ±  0.005)  ×  10-4 m2 s-1 and 4.8  ±  0.4 W m-1 K-1 for ACN and air, respectively. It is seen, that the determined values agree well within the range of their measurement uncertainties for both cases, although the measurement uncertainty is two times lower for the measurements in ACN providing more accurate results. The analysis is performed by the use of recently developed theoretical description based on the complex geometrical optics. It is also shown, how the presented work fits into the current status of photothermal beam deflection spectroscopy.

  8. Extraction of carrier lifetime in Ge waveguides using pump probe spectroscopy

    Science.gov (United States)

    Srinivasan, S. A.; Pantouvaki, M.; Verheyen, P.; Lepage, G.; Absil, P.; Van Campenhout, J.; Van Thourhout, D.

    2016-05-01

    Carrier lifetimes in Ge-on-Si waveguides are deduced using time-resolved infrared transmission pump-probe spectroscopy. Dynamics of pump-induced excess carriers generated in waveguides with varying Ge thickness and width is probed using a CW laser. The lifetimes of these excess carriers strongly depend on the thickness and width of the waveguide due to defect assisted surface recombination. Interface recombination velocities of 0.975 × 104 cm/s and 1.45 × 104 cm/s were extracted for the Ge/Si and the Ge/SiO2 interfaces, respectively.

  9. Determination of carrier lifetime and mobility in colloidal quantum dot films via impedance spectroscopy

    Science.gov (United States)

    Rath, Arup K.; Lasanta, Tania; Bernechea, Maria; Diedenhofen, Silke L.; Konstantatos, Gerasimos

    2014-02-01

    Impedance Spectroscopy (IS) proves to be a powerful tool for the determination of carrier lifetime and majority carrier mobility in colloidal quantum dot films. We employ IS to determine the carrier lifetime in PbS quantum dot Schottky solar cells with Al and we verify the validity of the technique via transient photovoltage. We also present a simple approach based on an RC model that allows the determination of carrier mobility in PbS quantum dot films and we corroborate the results via comparison with space charge limited measurements. In summary, we demonstrate the potential of IS to characterize key-to-photovoltaics optoelectronic properties, carrier lifetime, and mobility, in a facile way.

  10. Fluorescence lifetime spectroscopy in multiple-scattering environments: an application to biotechnology

    Science.gov (United States)

    Cerussi, Albert E.; Gratton, Enrico; Fantini, Sergio

    1999-07-01

    Over the past few years, there has been significant research activity devoted to the application of fluorescence spectroscopy to strongly scattering media, where photons propagate diffusely. Much of this activity focused on fluorescence as a source of contrast enhancement in optical tomography. Our efforts have emphasized the quantitative recovery of fluorescence parameters for spectroscopy. Using a frequency-domain diffusion-based model, we have successfully recovered the lifetime, the absolute quantum yield, the fluorophore concentration, and the emission spectrum of the fluorophore, as well as the absorption and the reduced scattering coefficients at the emission wavelength of the medium in different measurements. In this contribution, we present a sensitive monitor of the binding between ethidium bromide and bovine cells in fresh milk. The spectroscopic contrast was the approximately tenfold increase in the ethidium bromide lifetime upon binding to DNA. The measurement clearly demonstrated that we could quantitatively measure the density of cells in the milk, which is an application vital to the tremendous economic burden of bovine subclinical mastitis detection. Furthermore, we may in principle use the spirit of this technique as a quantitative monitor of the binding of fluorescent drugs inside tissues. This is a first step towards lifetime spectroscopy in tissues.

  11. Application of the Time of Flight Technique for Lifetime Measurements with Relativistic Beams of Heavy Nuclei

    CERN Document Server

    Chester, A; Bazin, D; Becerril, A; Campbell, C M; Cook, J M; Dewald, A; Dinca, D C; Miller, D; Moeller, V; Müller, W F; Norris, R P; Portillo, M; Starosta, K; Stolz, A; Terry, J R; Vaman, C; Zwahlen, H

    2006-01-01

    A novel method for picosecond lifetime measurements of excited gamma-ray emitting nuclear states has been developed for fast beams from fragmentation reactions. A test measurement was carried out with a beam of 124Xe at an energy of ~55 MeV/u. The beam ions were Coulomb excited to the first 2+ state on a movable target. Excited nuclei emerged from the target and decayed in flight after a distance related to the lifetime. A stationary degrader positioned downstream with respect to the target was used to further reduce the velocity of the excited nuclei. As a consequence, the gamma-ray decays from the 2+ excited state that occurred before or after traversing the degrader were measured at a different Doppler shift. The gamma-ray spectra were analyzed from the forward ring of the Segmented Germanium Array; this ring positioned at 37 deg. simultaneously provides the largest sensitivity to changes in velocity and the best energy resolution. The ratio of intensities in the peaks at different Doppler shifts gives inf...

  12. Development of time projection chamber for precise neutron lifetime measurement using pulsed cold neutron beams

    CERN Document Server

    Arimoto, Y; Igarashi, Y; Iwashita, Y; Ino, T; Katayama, R; Kitahara, R; Kitaguchi, M; Matsumura, H; Mishima, K; Oide, H; Otono, H; Sakakibara, R; Shima, T; Shimizu, H M; Sugino, T; Sumi, N; Sumino, H; Taketani, K; Tanaka, G; Tanaka, M; Tauchi, K; Toyoda, A; Yamada, T; Yamashita, S; Yokoyama, H; Yoshioka, T

    2015-01-01

    A new time projection chamber (TPC) was developed for neutron lifetime measurement using a pulsed cold neutron spallation source at the Japan Proton Accelerator Research Complex (J-PARC). Managing considerable background events from natural sources and the beam radioactivity is a challenging aspect of this measurement. To overcome this problem, the developed TPC has unprecedented features such as the use of polyether-ether-ketone plates in the support structure and internal surfaces covered with $^6$Li-enriched tiles to absorb outlier neutrons. In this paper, the design and performance of the new TPC are reported in detail.

  13. Development of time projection chamber for precise neutron lifetime measurement using pulsed cold neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Arimoto, Y. [High Energy Accelerator Research Organization, Ibaraki (Japan); Higashi, N. [Graduate School of Science, University of Tokyo, Tokyo (Japan); Igarashi, Y. [High Energy Accelerator Research Organization, Ibaraki (Japan); Iwashita, Y. [Institute for Chemical Research, Kyoto University, Kyoto (Japan); Ino, T. [High Energy Accelerator Research Organization, Ibaraki (Japan); Katayama, R. [Graduate School of Science, University of Tokyo, Tokyo (Japan); Kitaguchi, M. [Kobayashi-Maskawa Institute, Nagoya University, Aichi (Japan); Kitahara, R. [Graduate School of Science, Kyoto University, Kyoto (Japan); Matsumura, H.; Mishima, K. [High Energy Accelerator Research Organization, Ibaraki (Japan); Nagakura, N.; Oide, H. [Graduate School of Science, University of Tokyo, Tokyo (Japan); Otono, H., E-mail: otono@phys.kyushu-u.ac.jp [Research Centre for Advanced Particle Physics, Kyushu University, Fukuoka (Japan); Sakakibara, R. [Department of Physics, Nagoya University, Aichi (Japan); Shima, T. [Research Center for Nuclear Physics, Osaka University, Osaka (Japan); Shimizu, H.M.; Sugino, T. [Department of Physics, Nagoya University, Aichi (Japan); Sumi, N. [Faculty of Sciences, Kyushu University, Fukuoka (Japan); Sumino, H. [Department of Basic Science, University of Tokyo, Tokyo (Japan); Taketani, K. [High Energy Accelerator Research Organization, Ibaraki (Japan); and others

    2015-11-01

    A new time projection chamber (TPC) was developed for neutron lifetime measurement using a pulsed cold neutron spallation source at the Japan Proton Accelerator Research Complex (J-PARC). Managing considerable background events from natural sources and the beam radioactivity is a challenging aspect of this measurement. To overcome this problem, the developed TPC has unprecedented features such as the use of polyether-ether-ketone plates in the support structure and internal surfaces covered with {sup 6}Li-enriched tiles to absorb outlier neutrons. In this paper, the design and performance of the new TPC are reported in detail.

  14. In-beam spectroscopy of the heaviest elements

    Science.gov (United States)

    Herzberg, Rolf-Dietmar

    2016-12-01

    In-beam spectroscopy provides many powerful tools for the detailed study of nuclear structure. Over the past two decades the coupling of sensitive in-beam spectrometers to recoil separators has allowed the study of weakly populated reaction channels, such as the fusion-evaporation reactions leading to nuclei beyond fermium (Z = 100). The methods, observables, and limitations of this approach are discussed.

  15. Minority carrier lifetime in iodine-doped molecular beam epitaxy-grown HgCdTe

    Energy Technology Data Exchange (ETDEWEB)

    Madni, I.; Umana-Membreno, G. A.; Lei, W.; Gu, R.; Antoszewski, J.; Faraone, L. [School of Electrical, Electronic and Computer Engineering, The University of Western Australia, Crawley, Western Australia 6009 (Australia)

    2015-11-02

    The minority carrier lifetime in molecular beam epitaxy grown layers of iodine-doped Hg{sub 1−x}Cd{sub x}Te (x ∼ 0.3) on CdZnTe substrates has been studied. The samples demonstrated extrinsic donor behavior for carrier concentrations in the range from 2 × 10{sup 16} cm{sup −3} to 6 × 10{sup 17} cm{sup −3} without any post-growth annealing. At a temperature of 77 K, the electron mobility was found to vary from 10{sup 4} cm{sup 2}/V s to 7 × 10{sup 3} cm{sup 2}/V s and minority carrier lifetime from 1.6 μs to 790 ns, respectively, as the carrier concentration was increased from 2 × 10{sup 16} cm{sup −3} to 6 × 10{sup 17} cm{sup −3}. The diffusion of iodine is much lower than that of indium and hence a better alternative in heterostructures such as nBn devices. The influence of carrier concentration and temperature on the minority carrier lifetime was studied in order to characterize the carrier recombination mechanisms. Measured lifetimes were also analyzed and compared with the theoretical models of the various recombination processes occurring in these materials, indicating that Auger-1 recombination was predominant at higher doping levels. An increase in deep-level generation-recombination centers was observed with increasing doping level, which suggests that the increase in deep-level trap density is associated with the incorporation of higher concentrations of iodine into the HgCdTe.

  16. Characterization of control mesoporous glasses (CPGs) using positron annihilation lifetime spectroscopy (PALS)

    Energy Technology Data Exchange (ETDEWEB)

    Sayed Ahmed, Essmat Mahmoud Hassan

    2008-01-30

    This thesis has two main goals. Firstly and for the first time, the positron annihilation lifetime technique (PALS) is used to characterize the control porous glasses (CPGs) media. All the positron annihilation spectroscopy (PAS) investigations have been interested in the commercial Vycor glass media of pores size {<=} 4 nm. Therefore, the PALS is used to establish basic correlations between the important physical properties of the CPG (pore size, surface area, and porosity) and the orthopositronium (o-Ps) lifetime. The second goal is to use these correlations to verify the validity of some suggested models and theories to discover possible deviations from the expected behaviour and to discuss the physical point of view for these deviations. Chapter 1 presents an overview of positron, positronium and their interaction with solid materials. Chapter 2 of this thesis is concerned with characterization of porous glass materials. This chapter discusses in detail the preparation methods of porous glasses specially control porous glass and Vycor glass. The gas adsorption phenomenon in porous glass and the related definitions are discussed. The most important terms of the porous glass such as pore size, shape, volume, pore size distribution, surface area, and porosity are discussed. Chapter 3 presents in detail the well known models and the derived equations which correlate between the lifetime of the o-Ps long-lived component and the pore size, pore shape and the temperature dependence of the porous media. Chapter 4 presents an overview of the main experimental techniques used in this thesis, namely positron annihilation lifetime spectroscopy. Chapter 5 explains the sample preparation for the measurements. The chapter represents also the experimental data for the correlation between the o-Ps lifetime and pore sizes for a system of CPG media (from 1 nm to 64 nm). I also studied the temperature dependence of the o-Ps long-lived component in different pore sizes. In this

  17. Studies of unicellular microorganisms Saccharomyces cerevisiae by means of positron annihilation lifetime spectroscopy

    Directory of Open Access Journals (Sweden)

    Kubicz Ewelina

    2015-12-01

    Full Text Available Results of positron annihilation lifetime spectroscopy (PALS and microscopic studies on simple microorganisms, brewing yeasts, are presented. Lifetime of ortho-positronium (o-Ps were found to change from 2.4 to 2.9 ns (longer-lived component for lyophilized and aqueous yeasts, respectively. Also hygroscopicity of yeasts in time was examined, allowing to check how water – the main component of the cell – affects PALS parameters, thus lifetime of o-Ps were found to change from 1.2 to 1.4 ns (shorter-lived component for the dried yeasts. The time sufficient to hydrate the cells was found below 10 hours. In the presence of liquid water, an indication of reorganization of yeast in the molecular scale was observed. Microscopic images of the lyophilized, dried, and wet yeasts with best possible resolution were obtained using inverted microscopy (IM and environmental scanning electron microscopy (ESEM methods. As a result, visible changes to the surface of the cell me mbrane were observed in ESEM images.

  18. Electric field of a buried interfacial region measured by positron-lifetime spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Shek, Y.F.; Ling, C.C.; Beling, C.D.; Fung, S. [Hong Kong Univ. (Hong Kong). Dept. of Physics

    2002-02-01

    Positrons from a radioactive source are implanted into a reverse-biased metal-semiconductor contact and are drifted back towards the contact by the internal electric field where they trap into voids and annihilate. The electric field dependent interface annihilation fraction is monitored by way of the intensity of the long ({proportional_to}400-500 ps) void lifetime component using positron-lifetime spectroscopy. Unlike previous analyses of such systems a numerical model involving positron drift, annihilation and trapping into the interfacial state has been constructed to describe the positron dynamics in the presence of the non-uniform junction electric field. The use of the positron-lifetime technique in probing the internal electric field at buried contacts is thus demonstrated. Results obtained using the numerical method for the Au, Al and Ni/Semi-Insulating (SI)-GaAs contact systems are found to be consistent with the findings of previous studies on the Au/SI-GaAs system. (orig.)

  19. Free volume investigation of imidazolium ionic liquids from positron lifetime spectroscopy

    CERN Document Server

    Yu, Yang; Krause-Rehberg, Reinhard

    2014-01-01

    In this work, relationships between the free volume and various fundamental physical properties (density, surface tension and transport properties) of ionic liquids were investigated. Two imidazolium ionic liquids 1-butyl-3-methylimidazolium tris(pentafluoroethyl)trifluoro phosphate ([C4MIM][FAP]) and 1-butyl-3-methylimidazolium bis[bis(pentafluoroethyl)phosphinyl]imide ([C4MIM][FPI]) were measured by positron annihilation lifetime spectroscopy (PALS). Changes of the ortho-positronium lifetime (o-Ps) with different states (amorphous and crystalline) were depicted as completely as possible. The mean local free (hole) volume was calculated from the o-Ps lifetime in amorphous state for the samples. Comparison between and specific volume obtained from the temperature dependent mass density gave the specific hole densities Nf and the occupied volumes Vocc. Thermal expansion of hole volume was compared with molecular volume VM of [C4MIM][FAP] and [C4MIM][FPI] as well as five other ionic liquids from our previous ...

  20. Characterization of interfaces in Binary and Ternary Polymer Blends by Positron Lifetime Spectroscopy

    Science.gov (United States)

    Ranganathaiah, C.

    2015-06-01

    A miscible blend is a single-phase system with compact packing of the polymeric chains/segments due configuration/conformational changes upon blending. Differential Scanning Calorimetry (DSC) is the most employed method to ascertain whether the blend is miscible or immiscible. Positron Lifetime Spectroscopy (PLS) has been employed in recent times to study miscibility properties of polymer blends by monitoring the ortho-Positronium annihilation lifetimes as function of composition. However, just free volume monitoring and the DSC methods fail to provide the composition dependent miscibility of blends. To overcome this limitation, an alternative approach based on hydrodynamic interactions has been developed to derive this information using the same o-Ps lifetime measurements. This has led to the development of a new method of measuring composition dependent miscibility level in binary and ternary polymer blends. Further, the new method also provides interface characteristics for immiscible blends. The interactions between the blend components has a direct bearing on the strength of adhesion at the interface and hence the hydrodynamic interaction. Understanding the characteristic of interfaces which decides the miscibility level of the blend and their end applications is made easy by the present method. The efficacy of the present method is demonstrated for few binary and ternary blends.

  1. Engineering the Activity and Lifetime of Heterogeneous Catalysts for Carbon Nanotube Growth via Substrate Ion Beam Bombardment (Postprint)

    Science.gov (United States)

    2014-07-31

    11,25 and chirality.19,20 CNTs are grown via heterogeneous catalysis using a thin film of catalyst on a wide variety of catalyst supports. Films of...another method in catalysis science to engineer supports to enhance both catalytic activity and lifetime with general implications for heterogeneous ...AFRL-RX-WP-JA-2014-0159 ENGINEERING THE ACTIVITY AND LIFETIME OF HETEROGENEOUS CATALYSTS FOR CARBON NANOTUBE GROWTH VIA SUBSTRATE ION BEAM

  2. The TRIple PLunger for EXotic beams TRIPLEX for excited-state lifetime measurement studies on rare isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Iwasaki, H., E-mail: iwasaki@nscl.msu.edu [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Dewald, A.; Braunroth, T.; Fransen, C. [Institut für Kernphysik der Universität zu Köln, D-50937 Cologne (Germany); Smalley, D. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Lemasson, A. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); Morse, C.; Whitmore, K.; Loelius, C. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States)

    2016-01-11

    A new device, the TRIple PLunger for EXotic beams (TRIPLEX), has been developed for lifetime measurement studies with rare isotope beams. This plunger device holds up to three metal foils in the beam path and facilitates the recoil distance Doppler-shift technique to measure lifetimes of nuclear excited states in the range of 1 ps to 1 ns. The unique design allows independent movement of the target and the second degrader with respect to a fixed first degrader in between, enabling advanced experimental approaches, such as the differential recoil distance method and the double recoil distance method. The design and control of the device are presented in this paper, together with simulated performances of the new applications. As an example of actual experiments, results from the lifetime measurement of the neutron-rich {sup 17}C isotope performed at the National Superconducting Cyclotron Laboratory are shown.

  3. Lifetime dependence of nitrided carbon stripper foils on sputter angle during N{sup +} ion beam sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Sugai, I., E-mail: isao.Sugai@kek.jp [High Energy Accelerator Research Organization, Accelerator Laboratory, Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Oyaizu, M. [High Energy Accelerator Research Organization, Institute of Particle and Nuclear Studies, Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Takeda, Y. [High Energy Accelerator Research Organization, Accelerator Laboratory, Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Kawakami, H. [High Energy Accelerator Research Organization, Institute of Particle and Nuclear Studies, Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Kawasaki, K.; Hattori, T. [Department of Physics, Tokyo Institute of Technology, Ohokayama, Meguro, Tokyo 152-8550 (Japan); Kadono, T. [Department of Physics, University of Tokyo, Hongo, 7-3-1, Bunkyo, Tokyo 113-0033 (Japan)

    2015-09-01

    We fabricated high-lifetime thin nitride carbon stripper (NCS) foils with high nitrogen contents using ion-beam sputtering with reactive nitrogen gas and investigated the dependence of their lifetimes on the sputter angle. The nitrogen in carbon foils plays a critical role in determining their lifetime. Therefore, in order to investigate the effects of the nitrogen level in NCS foils on foil lifetime, we measured the sputtering yield for different sputter angles at a sputtering voltage of 10 kV while using carbon-based targets. We also measured the nitrogen-to-carbon thickness ratios of the foils using Rutherford backscattering spectrometry. The foils made at a sputter angle of 15° using a glassy amorphous carbon target exhibited an average increase of 200-fold in lifetime when compared to commercially available foils.

  4. Scrape-off layer-induced beam density fluctuations and their effect on beam emission spectroscopy

    Science.gov (United States)

    Moulton, D.; Marandet, Y.; Tamain, P.; Dif-Pradalier, G.

    2015-07-01

    A statistical model is presented to calculate the magnitude of beam density fluctuations generated by a turbulent scrape-off layer (SOL). It is shown that the SOL can induce neutral beam density fluctuations of a similar magnitude to the plasma density fluctuations in the core, potentially corrupting beam emission spectroscopy measurements. The degree of corruption is quantified by combining simulations of beam and plasma density fluctuations inside a simulated measurement window. A change in pitch angle from the separatrix to the measurement window is found to reduce the effect of beam fluctuations, whose largest effect is to significantly reduce the measured correlation time.

  5. Scalable Focused Ion Beam Creation of Nearly Lifetime-Limited Single Quantum Emitters in Diamond Nanostructures

    CERN Document Server

    Schröder, Tim; Walsh, Michael; Li, Luozhou; Zheng, Jiabao; Schukraft, Marco; Pacheco, Jose L; Camacho, Ryan M; Bielejec, Edward S; Sipahigil, Alp; Evans, Ruffin E; Sukachev, Denis D; Nguyen, Christian T; Lukin, Mikhail D; Englund, Dirk

    2016-01-01

    The controlled creation of defect center---nanocavity systems is one of the outstanding challenges for efficiently interfacing spin quantum memories with photons for photon-based entanglement operations in a quantum network. Here, we demonstrate direct, maskless creation of atom-like single silicon-vacancy (SiV) centers in diamond nanostructures via focused ion beam implantation with $\\sim 32$ nm lateral precision and $< 50$ nm positioning accuracy relative to a nanocavity. Moreover, we determine the Si+ ion to SiV center conversion yield to $\\sim 2.5\\%$ and observe a 10-fold conversion yield increase by additional electron irradiation. We extract inhomogeneously broadened ensemble emission linewidths of $\\sim 51$ GHz, and close to lifetime-limited single-emitter transition linewidths down to $126 \\pm13$ MHz corresponding to $\\sim 1.4$-times the natural linewidth. This demonstration of deterministic creation of optically coherent solid-state single quantum systems is an important step towards development o...

  6. Molecular-beam spectroscopy of interhalogen molecules

    Energy Technology Data Exchange (ETDEWEB)

    Sherrow, S.A.

    1983-08-01

    A molecular-beam electric-resonance spectrometer employing a supersonic nozzle source has been used to obtain hyperfine spectra of /sup 79/Br/sup 35/Cl. Analyses of these spectra and of microwave spectra published by other authors have yielded new values for the electric dipole moment and for the nuclear quadrupole coupling constants in this molecule. The new constants are significantly different from the currently accepted values. Van der Waals clusters containing chlorine monofluoride have been studied under various expansion conditions by the molecular-beam electric-deflection method. The structural possibilities indicated by the results are discussed, and cluster geometries are proposed.

  7. Polarization Studies in Fast-Ion Beam Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Trabert, E

    2001-12-20

    In a historical review, the observations and the insight gained from polarization studies of fast ions interacting with solid targets are presented. These began with J. Macek's recognition of zero-field quantum beats in beam-foil spectroscopy as indicating alignment, and D.G. Ellis' density operator analysis that suggested the observability of orientation when using tilted foils. Lastly H. Winter's studies of the ion-beam surface interaction at grazing incidence yielded the means to produce a high degree of nuclear orientation in ion beams.

  8. Structural studies of spinel manganite ceramics with positron annihilation lifetime spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Klym, H; Shpotyuk, O; Hadzaman, I [Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, 79031 (Ukraine); Ingram, A [Opole University of Technology, 75 Ozimska str., Opole, 45370 (Poland); Filipecki, J, E-mail: shpotyuk@novas.lviv.ua, E-mail: klymha@yahoo.com [Institute of Physics of Jan Dlugosz University, 13/15 Armii Krajowei, 42201, Czestochowa (Poland)

    2011-04-01

    The new transition-metal manganite Cu{sub 0.1}Ni{sub 0.8}Co{sub 0.2}Mn{sub 1.9}O{sub 4} ceramics for temperature sensors with improved functional reliability are first proposed. It is established that the amount of additional NiO phase in these ceramics extracted during sintering play a decisive role. This effect is well revealed only in ceramics having a character fine-grain microstructure, while the monolithization of ceramics caused by great amount of transferred thermal energy reveals an opposite influence. The process of monolitization from the position of evolution of grain-pore structure was studied in these ceramics using positron annihilation lifetime spectroscopy.

  9. Study of PRIMAVERA steel samples by positron annihilation spectroscopy technique II - Lifetime measurements

    Science.gov (United States)

    Krsjak, V.; Grafutin, V.; Ilyukhina, O.; Burcl, R.; Ballesteros, A.; Hähner, P.

    2012-02-01

    In the present article, a positron annihilation lifetime technique was used for the study of VVER-440/230 weld materials, manufactured in the frame of the international PRIMAVERA project on microstructural investigation of the irradiated WWER-440 reactor pressure vessel steel. The present results complement our previous report of positron angular correlation experiments and provide in-depth characterization of vacancy type defects behavior under irradiation and thermal treatment. The results give new insight into the previously published atom probe tomography and angular correlation of annihilation radiation studies. The measurements do not show any association of phosphorus or its segregation to the open volume defects investigated by positron annihilation spectroscopy. The embrittlement effects related to the phosphorus seem to be effectively annealed-out during 475 °C thermal treatment and the post annealing microstructure and mechanical properties of the material are consequently affected mostly by agglomerations of vacancy clusters coarsened during thermal treatment.

  10. Positron annihilation lifetime spectroscopy of mechanically milled protein fibre powders and their free volume aspects

    Science.gov (United States)

    Patil, K.; Sellaiyan, S.; Rajkhowa, R.; Tsuzuki, T.; Lin, T.; Smith, S. V.; Wang, X.; Uedono, A.

    2013-06-01

    The present study reports the fabrication of ultra-fine powders from animal protein fibres such as cashmere guard hair, merino wool and eri silk along with their free volume aspects. The respectively mechanically cleaned, scoured and degummed cashmere guard hair, wool and silk fibres were converted into dry powders by a process sequence: Chopping, Attritor Milling, and Spray Drying. The fabricated protein fibre powders were characterised by scanning electron microscope, particle size distribution and positron annihilation lifetime spectroscopy (PALS). The PALS results indicated that the average free volume size in protein fibres increased on their wet mechanical milling with a decrease in the corresponding intensities leading to a resultant decrease in their fractional free volumes.

  11. Nanoporous Structure in Low-Dielectric Films with Positronium Annihilation Lifetime Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    HU Yi-Fan; SUN Jia-Ning; D. W. Gidley

    2005-01-01

    @@ We investigate nano-porous structures in thin low-dielectric films, i.e. the pore sizes, distributions, and interconnectivity, by using depth profiled positronium annihilation lifetime spectroscopy (PALS). It is found that PALS has good sensitivity to probe both interconnected and closed pores in the range from 0.3nm to 30nm, even in the film buried beneath a diffusion barrier. A series of low dielectric constant films of organosilicon-silsequioxane with different weight percentages of porogen have been comparatively investigated. The PALS technique can be used to distinguish the open porosity from the closed one, to determine the pore size, and to detect the percolation threshold with the increasing porosity that represents the transition from closed pores to interconnected pores.Furthermore, the pore percolation length can be derived.

  12. Lifetime-resolved photoacoustic (LPA) spectroscopy for monitoring oxygen change and photodynamic therapy (PDT)

    Science.gov (United States)

    Jo, Janggun; Lee, Chang Heon; Kopelman, Raoul; Wang, Xueding

    2016-03-01

    The Methylene Blue loaded Polyacrylamide Nanoparticles (MB-PAA NPs) are used for oxygen sensing and Photodynamic therapy (PDT), a promising therapeutic modality employed for various tumors, with distinct advantages of delivery of biomedical agents and protection from other bio-molecules overcoming inherent limitations of molecular dyes. Lifetime-resolved photoacoustic spectroscopy using quenched-phosphorescence method is applied with MB-PAA NPs so as to sense oxygen, while the same light source is used for PDT. The dye is excited by absorbing 650 nm wavelength light from a pump laser to reach triplet state. The probe laser at 810 nm wavelength is used to excite the first triplet state at certain delayed time to measure the dye lifetime which indicates oxygen concentration. The 9L cells (106 cells/ml) incubated with MB-PAA NP solution are used for monitoring oxygen level change during PDT in situ test. The oxygen level and PDT efficacy are confirmed with a commercial oximeter, and fluorescence microscope imaging and flow cytometry results. This technique with the MB-PAA NPs allowed us to demonstrate a potential non-invasive theragnostic operation, by monitoring oxygen depletion during PDT in situ, without the addition of secondary probes. Here, we demonstrate this theragnostic operation, in vitro, performing PDT while monitoring oxygen depletion. We also show the correlation between O2 depletion and cell death.

  13. Precision atomic beam density characterization by diode laser absorption spectroscopy

    Science.gov (United States)

    Oxley, Paul; Wihbey, Joseph

    2016-09-01

    We provide experimental and theoretical details of a simple technique to determine absolute line-of-sight integrated atomic beam densities based on resonant laser absorption. In our experiments, a thermal lithium beam is chopped on and off while the frequency of a laser crossing the beam at right angles is scanned slowly across the resonance transition. A lock-in amplifier detects the laser absorption signal at the chop frequency from which the atomic density is determined. The accuracy of our experimental method is confirmed using the related technique of wavelength modulation spectroscopy. For beams which absorb of order 1% of the incident laser light, our measurements allow the beam density to be determined to an accuracy better than 5% and with a precision of 3% on a time scale of order 1 s. Fractional absorptions of order 10-5 are detectable on a one-minute time scale when we employ a double laser beam technique which limits laser intensity noise. For a lithium beam with a thickness of 9 mm, we have measured atomic densities as low as 5 × 104 atoms cm-3. The simplicity of our technique and the details we provide should allow our method to be easily implemented in most atomic or molecular beam apparatuses.

  14. Radiative lifetime measurements of some Tm I and Tm II levels by time-resolved laser spectroscopy

    Science.gov (United States)

    Tian, Yanshan; Wang, Xinghao; Yu, Qi; Li, Yongfan; Gao, Yang; Dai, Zhenwen

    2016-04-01

    Radiative lifetimes of 88 levels of Tm I in the energy range 22 791.176-48 547.98 cm-1 and 29 levels of Tm II in the range 27 294.79-65 612.85 cm-1 were measured by time-resolved laser-induced fluorescence spectroscopy in laser-ablation plasma. The lifetime values obtained are in the range from 15.4 to 7900 ns for Tm I and from 36.5 to 1000 ns for Tm II. To the best of our knowledge, 77 lifetimes of Tm I and 22 lifetimes of Tm II are reported for the first time. Good agreements between the present results and the previous experimental values were achieved for both Tm I and Tm II.

  15. Multiphoton microscopy, fluorescence lifetime imaging and optical spectroscopy for the diagnosis of neoplasia

    Science.gov (United States)

    Skala, Melissa Caroline

    2007-12-01

    Cancer morbidity and mortality is greatly reduced when the disease is diagnosed and treated early in its development. Tissue biopsies are the gold standard for cancer diagnosis, and an accurate diagnosis requires a biopsy from the malignant portion of an organ. Light, guided through a fiber optic probe, could be used to inspect regions of interest and provide real-time feedback to determine the optimal tissue site for biopsy. This approach could increase the diagnostic accuracy of current biopsy procedures. The studies in this thesis have characterized changes in tissue optical signals with carcinogenesis, increasing our understanding of the sensitivity of optical techniques for cancer detection. All in vivo studies were conducted on the dimethylbenz[alpha]anthracene treated hamster cheek pouch model of epithelial carcinogenesis. Multiphoton microscopy studies in the near infrared wavelength region quantified changes in tissue morphology and fluorescence with carcinogenesis in vivo. Statistically significant morphological changes with precancer included increased epithelial thickness, loss of stratification in the epithelium, and increased nuclear diameter. Fluorescence changes included a statistically significant decrease in the epithelial fluorescence intensity per voxel at 780 nm excitation, a decrease in the fluorescence lifetime of protein-bound nicotinamide adenine dinucleotide (NADH, an electron donor in oxidative phosphorylation), and an increase in the fluorescence lifetime of protein-bound flavin adenine dinucleotide (FAD, an electron acceptor in oxidative phosphorylation) with precancer. The redox ratio (fluorescence intensity of FAD/NADH, a measure of the cellular oxidation-reduction state) did not significantly change with precancer. Cell culture experiments (MCF10A cells) indicated that the decrease in protein-bound NADH with precancer could be due to increased levels of glycolysis. Point measurements of diffuse reflectance and fluorescence spectra in

  16. Beam lifetime measurement using beam position monitor in SSRF%用束流位置监测器测量上海光源束流寿命

    Institute of Scientific and Technical Information of China (English)

    阎映炳; 冷用斌; 赖龙伟; 张宁; 易星; 杨桂森

    2012-01-01

    The output signal of beam position monitor (BPM) carries not only position information but also charge information. It can reflect the changes of the beam charge and be used for beam lifetime measurement. In this paper, the feasibility of beam lifetime measurement using BPM was investigated through theoretical analysis. Some experiments were conducted on the storage ring of Shanghai Synchrotron Radiation Facility(SSRF) to evaluate the performance. Compared with the DC current transformer( DCCT) system, the lifetime measured by BPM has higher data rate and resolution. It is useful for the beam lifetime evaluation of different time scales and the measurement accuracy can be further improved by averaging the results of multiple BPMs.%通过理论分析研究了电磁耦合型束流位置探测器(BPM)用于束流寿命测量的可行性,并在上海光源储存环上进行了束流实验,对其性能进行了评估.实验结果表明,与目前常用的直流流强变压器(DCCT)系统相比,BPM给出的束流寿命具有更高的带宽和分辨力,有利于进行不同时间尺度的束流寿命评估,而且可以通过多个平均的方式来进一步提高测量精度.

  17. Preparing a dedicated set up for level lifetime measurements using the recoil Doppler shift technique with fast radioactive beams

    Energy Technology Data Exchange (ETDEWEB)

    Hackstein, M.; Fransen, C.; Dewald, A.; Braun, N.; Braunroth, T.; Jolie, J.; Litzinger, J.; Moschner, K.; Reiter, P.; Pfeiffer, M.; Rother, W.; Taprogge, J.; Wendt, A.; Zell, K.O. [IKP, Univ. zu Koeln (Germany); Algora, A.; Doncel, M.; Gadea, A. [Instituto de Fisica Corpuscular (IFIC), Valencia (Spain); Ameil, F.; Boutachkov, P.; Gerl, J.; Grebosz, J.; Guastalla, G.; Habermann, T.; Kurz, N.; Merchan, E.; Nociforo, C.; Pietri, S.; Quitana, B.; Wollersheim, H. [KP II, GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Corsi, A.; Louchar, C.; Obertelli, A. [CEA Saclay (France); Reese, M. [IKP, TU Darmstadt (Germany); Petkov, P. [INRNE, Sofia (Bulgaria)

    2012-07-01

    In this paper we report on the development of a new plunger device especially designed to meet the constraints found at the fragment recoil separator (FRS) at GSI (Darmstadt) in combination with PRESPEC. The aim is to measure level lifetimes in the pico-second range using the recoil distance Doppler shift (RDDS) method of states in exotic nuclei excited via Coulomb excitation or knock-out reactions with radioactive beams at relativistic energies. We also report on the first results obtained from a first commissioning run performed recently with a stable {sup 54}Cr beam.

  18. Hard X-ray emission spectroscopy with pink beam

    Energy Technology Data Exchange (ETDEWEB)

    Kvashnina, Kristina O.; Rossberg, Andre; Exner, Joerg; Scheinost, Andreas C. [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Molecular Structures

    2017-06-01

    Valence-band X-ray emission spectroscopy (XES) with a ''pink beam'', i.e. a beam with large energy bandwidth produced by a double-multilayer monochromator, is introduced here to overcome the weak count rate of monochromatic beams produced by conventional double-crystal monochromators. Our results demonstrate that - in spite of the large bandwidth in the order of 100 eV - the high spectral resolution of the Johann-type spectrometer is maintained, while the two orders of magnitude higher flux greatly reduces the required counting time. The short working distance Johann-type X-ray emission spectrometer and multilayer monochromator is available at ROBL.

  19. On-line laser spectroscopy with thermal atomic beams

    CERN Document Server

    Thibault, C; De Saint-Simon, M; Duong, H T; Guimbal, P; Huber, G; Jacquinot, P; Juncar, P; Klapisch, Robert; Liberman, S; Pesnelle, A; Pillet, P; Pinard, J; Serre, J M; Touchard, F; Vialle, J L

    1981-01-01

    On-line high resolution laser spectroscopy experiments have been performed in which the light from a CW tunable dye laser interacts at right angles with a thermal atomic beam. /sup 76-98/Rb, /sup 118-145 /Cs and /sup 208-213/Fr have been studied using the ionic beam delivered by the ISOLDE on-line mass separator at CERN while /sup 30-31/Na and /sup 38-47/K have been studied by setting the apparatus directly on-line with the PS 20 GeV proton beam. The principle of the method is briefly explained and some results concerning nuclear structure are given. The hyperfine structure, spins and isotope shifts of the alkali isotopes and isomers are measured. (8 refs).

  20. Positron annihilation lifetime spectroscopy (PALS) application in metal barrier layer integrity for porous low- k materials

    CERN Document Server

    Simon, Lin; Gidley, D W; Wetzel, J T; Monnig, K A; Ryan, E T; Simon, Jang; Douglas, Yu; Liang, M S; En, W G; Jones, E C; Sturm, J C; Chan, M J; Tiwari, S C; Hirose, M

    2002-01-01

    Positron Annihilation Lifetime Spectroscopy (PALS) is a useful tool to pre-screen metal barrier integrity for Si-based porous low-k dielectrics. Pore size of low-k, thickness of metal barrier Ta, positronium (Ps) leakage from PALS, trench sidewall morphology, electrical test from one level metal (1LM) pattern wafer and Cu diffusion analysis were all correlated. Macro-porous low-k (pore size >=200 AA) and large scale meso-porous low-k (>50~200 AA) encounter both Ps leakage and Cu diffusion into low-k dielectric in the 0.25 mu mL/0.3 mu mS structures when using SEMATECH in-house PVD Ta 250 AA as barrier layer. For small scale meso-porous (>20~50 AA) and micro- porous (<=20 AA) low-k, no Ps leakage and no Cu diffusion into low-k were observed even with PVD Ta 50 AA, which is proved also owing to sidewall densification to seal all sidewall pores due to plasma etch and ash. For future technology, smaller pore size of porous Si-based low-k (=<50 AA) will be preferential for dense low-k like trench sidewall to...

  1. Clay particles - potential of positron annihilation lifetime spectroscopy (PALS) for studying interlayer spacing

    Energy Technology Data Exchange (ETDEWEB)

    Fong, N; Smith, S V [Centre for Antimatter-Matter Studies, Australian Nuclear Science and Technology Organisation (ANSTO), Menai, NSW 2234 (Australia); Guagliardo, P; Williams, J [Centre for Antimatter-Matter Studies, School of Physics, University of Western Australia, WA 6009 (Australia); Musumeci, A; Martin, D, E-mail: nfg@ansto.gov.au [ARC Centre of Excellence for Functional Nanomaterials, Australian Institute for Bioengineering and Nanotechnology, University of Queensland, QLD (Australia)

    2011-01-01

    Characterisation of clays is generally achieved by traditional methods, such as X-ray diffraction (XRD) and transmission electron microscopy (TEM). However, clays are often difficult to characterise due to lack of long-range order, thus these tools are not always reliable. Because interlayer spacing in clays can be adjusted to house molecules, there is growing interest to use these materials for drug delivery. Positron annihilation lifetime spectroscopy (PALS) was examined as an alternative tool to characterise a series of well-known clays. XRD of two layered double hydroxides; MgAl-LDH and MgGd-LDH, natural hectorite, fluoromica and laponite, and their PALS spectra were compared. XRD data was used to calculate the interlayer d- spacing in these materials and results show a decrease in interlayer spacing as the heavy metal ions are substituted for those of large ionic radii. Similar results were obtained for PALS data. This preliminary study suggests PALS has potential as a routine tool for characterising clay particles. Further work will examine the sensitivity and reliability of PALS to percent of metal doping and hydration in clay microstructure.

  2. Application of the time-of-flight technique for lifetime measurements with relativistic beams of heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chester, A. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, 164 S. Shaw Lane, East Lansing, MI 48825-1321 (United States); Adrich, P. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, 164 S. Shaw Lane, East Lansing, MI 48825-1321 (United States); Becerril, A. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, 164 S. Shaw Lane, East Lansing, MI 48825-1321 (United States)] (and others)

    2006-06-15

    A novel method for picosecond lifetime measurements of excited {gamma}-ray emitting nuclear states has been developed for fast beams from fragmentation reactions. A test measurement was carried out with a beam of {sup 124}Xe at an energy of {approx}55MeV/u. The beam ions were Coulomb excited to the 2{sub 1}{sup +} state on a movable target. Excited nuclei emerged from the target and decayed in flight after a distance related to the lifetime. A stationary degrader positioned downstream with respect to the target was used to further reduce the velocity of the excited nuclei. As a consequence, the {gamma}-ray decays from the 2{sub 1}{sup +} excited state that occurred before or after traversing the degrader were measured at a different Doppler shift. The {gamma}-ray spectra were analyzed from the forward ring of the Segmented Germanium Array; this ring positioned at 37{sup -}bar simultaneously provides the largest sensitivity to changes in {beta} and the best-energy resolution. The ratio of intensities in the peaks at different Doppler shifts gives information about the lifetime if the velocity {beta} is measured. The results and range of the application of the method are discussed.

  3. Positronium formation in NaY-zeolites studied by lifetime, positron beam Doppler broadening and 3-gamma detection techniques

    CERN Document Server

    Schut, H; Kolar, Z I; Veen, A V; Clet, G

    2000-01-01

    Results of positron annihilation measurements on NaY pressed powders and deposited thin films using slow positron beam and conventional fast positron techniques are presented. In lifetime experiments using an external sup sup 2 sup sup 2 Na source an averaged long lifetime of 1.8 ns with a sum intensity of 27% was observed in pressed powders in the presence of air at room temperature (RT). In literature this lifetime is ascribed to positrons annihilating in water filled alpha or beta cages Habrowska, A.M., Popiel, E.S., 1987. Positron annihilation in zeolite 13X. J. Appl. Phys. 62, 2419. By means of isotopic exchange some of the Na was replaced by sup sup 2 sup sup 2 Na. These powders showed a long lifetime component of 7-8 ns with an intensity increasing from 1 to 12% when heated under normal atmosphere from RT to 200 deg. C. No significant increase of the shorter (1.5 ns) lifetime was observed, while its intensity dropped from 13.4 to 6.6%. Both effects are ascribed to the loss of water from alpha cages onl...

  4. Positron lifetime measurements and positron-annihilation induced auger electron spectroscpy using slow positron beams; Teisoku yodenshi bimu wo mochiita yodenshi jumyo sokutei oyobi yodenshi shometsu reiki oje denshi bunko

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, R. [Electrotechnical Lab., Tsukuba (Japan)

    1996-02-20

    Slow positron beam with less than several eV can be controlled freely such as accelerating, throttling the beam size, shortening the pulse or making pulse with short time width and so forth. These low positron beams are applied to various measurements like Doppler broadening measurement of annihilation {gamma} rays or lifetime measurement of positron, and secondary particle measurements using positron microscope, positron electron ray diffraction, flight time method and so forth. In particular, these recent years, high intensity slow positron beams were possible using accelerators like electron linac and its application is increasing. In this report, pulse shortening method for high intensity slow positron beam, and incidence energy variable positron lifetime measurement method using this slow pulsed beam and flight time type positron-annihilation-induced auger electron spectroscopy are outlined. In future, these measurements can be possible to carry out with high resolution and also with high counting rate if higher intensity monochromatic excellent positron beam than present one is produced. 31 refs., 5 figs.

  5. Radiative lifetime measurements of odd-parity highly-excited levels of Sn I by time-resolved laser spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Xu Jia-Xin; Feng Yan-Yan; Sun Gui-Juan; Dai Zhen-Wen

    2009-01-01

    Natural radiative lifetimes of five higher-lying odd-parity levels 5pTs 3p1o,5p5d 1p1o,5p6d 3F2o,3D1o and 3F3o in neutral tin are measured by the time-resolved laser-induced fluorescence (TR-LIF) technique and the atomic beam method. All these lifetimes are not longer than 100 ns and they are found to be shorter than the lifetimes of evenparity levels in the same energy region. The results reported in this paper provide important transition parameters for highly-excited atomic Sn,which may be useful for theoretically calculating excited heavy atoms.

  6. Combined in-beam gamma-ray and conversion electron spectroscopy with radioactive ion beams

    Directory of Open Access Journals (Sweden)

    Konki J.

    2013-12-01

    Full Text Available In-beam gamma-ray and electron spectroscopy have been widely used as tools to study the broad variety of phenomena in nuclear structure. The SPEDE spectrometer is a new device to be used in conjunction with the MINIBALL germanium detector array to enable the detection of internal conversion electrons in coincidence with gamma rays from de-exciting nuclei in radioactive ion beam experiments at the upcoming HIE-ISOLDE facility at CERN, Switzerland. Geant4 simulations were carried out in order to optimise the design and segmentation of the silicon detector to achieve good energy resolution and performance.

  7. Application of positron lifetime spectroscopy to the study of material processing of Nd-Fe-B permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Nishiuchi, T., E-mail: Takeshi_Nishiuchi@hitachi-metals.co.j [Magnetic Materials Research Laboratory, NEOMAX Company, Hitachi Metals Ltd., 2-15-17 Egawa, Shimamoto, Osaka 618-0013 (Japan); Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Sakashita, S.; Hirosawa, S. [Magnetic Materials Research Laboratory, NEOMAX Company, Hitachi Metals Ltd., 2-15-17 Egawa, Shimamoto, Osaka 618-0013 (Japan); Nakamura, M.; Kakimoto, M.; Kawabayashi, T.; Mizuno, M.; Araki, H. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Shirai, Y. [Graduate School of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan)

    2010-05-15

    A positron lifetime spectroscopy was applied to a series of samples of Nd-Fe-B based alloys prepared by hydrogenation-disproportionation-desorption-recombination (HDDR) process with various desorption-recombination (DR) times and the results were compared to the results of cross-sectional observation with scanning electron microscopy (SEM). From these studies, it is strongly suggested that microstructural changes, which causes the sudden onset of coercivity during DR stage progress abruptly in a relatively short period of time. Positron lifetime spectroscopy can detect the microstructural changes during DR treatment and furthermore, it is suggested that positron annihilation site is directly related to the region which determines the coercivity of the HDDR-processed Nd-Fe-B alloys.

  8. Enhancement of minority carrier lifetime of GaInP with lateral composition modulation structure grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Park, K. W.; Ravindran, Sooraj; Kang, S. J.; Hwang, H. Y.; Jho, Y. D. [School of Information and Communications, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Park, C. Y. [School of Information and Communications, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Jo, Y. R.; Kim, B. J. [School of Material Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Lee, Y. T., E-mail: ytlee@gist.ac.kr [School of Information and Communications, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of)

    2014-07-28

    We report the enhancement of the minority carrier lifetime of GaInP with a lateral composition modulated (LCM) structure grown using molecular beam epitaxy (MBE). The structural and optical properties of the grown samples are studied by transmission electron microscopy and photoluminescence, which reveal the formation of vertically aligned bright and dark slabs corresponding to Ga-rich and In-rich GaInP regions, respectively, with good crystal quality. With the decrease of V/III ratio during LCM GaInP growth, it is seen that the band gap of LCM GaInP is reduced, while the PL intensity remains high and is comparable to that of bulk GaInP. We also investigate the minority carrier lifetime of LCM structures made with different flux ratios. It is found that the minority carrier lifetime of LCM GaInP is ∼37 times larger than that of bulk GaInP material, due to the spatial separation of electrons and holes by In-rich and Ga-rich regions of the LCM GaInP, respectively. We further demonstrate that the minority carrier lifetime of the grown LCM GaInP structures can easily be tuned by simply adjusting the V/III flux ratio during MBE growth, providing a simple yet powerful technique to tailor the electrical and optical properties at will. The exceptionally high carrier lifetime and the reduced band gap of LCM GaInP make them a highly attractive candidate for forming the top cell of multi-junction solar cells and can enhance their efficiency, and also make them suitable for other optoelectronics devices, such as photodetectors, where longer carrier lifetime is beneficial.

  9. Characteristics of vinyl-ester and carbon fiber composite dry and wet probe by Positron Annihilation Lifetime Spectroscopy

    Science.gov (United States)

    Madani, Mahmoud; Granata, Richard D.

    2015-03-01

    Carbon fiber composites of vinylester resins, Derakane 8084 and 510A, were studied dry and after water exposure. In this study, positron annihilation lifetime spectroscopy (PALS) was used to investigate the free volume fraction and the size of the free volume voids within the polymer matrix. The relative free volume (fractions replae by of positron lifetime intensities) in VE8084 polymer and in VE510A (Space) polymer were 35.2% and 13.8%, respectively. The free volume lifetime and intensities were determined as a function of the polymer thickness and significant differences were observed in both polymers with versus without post-curing. The effects of water uptake in these materials were also determined by PALS. Water uptake showed a 2% change in intensity of the longer lifetime (1.85 ns) in VE8084 polymer and in VE510A about 1.8%. The longer lifetime intensities in the wet composites were 17.1% in the 8084 polymer and its carbon fiber composite and 7.1% in the 510A polymer and its carbon fiber composite. For composite with 8084 polymer saturated (0.33% water gain) with seawater at 40 or 60 °C, no change in the longer lifetime intensity was observed which indicates no water entered the free volume voids (indicates replace by and) some differences between composite and neat polymer. For 510A resin the third lifetime intensity dropped from 7.1% to 3.9% indicating 48% of the free volume filled with water in the composite only after saturation with seawater with respect to dry one.

  10. Source fabrication and lifetime for Li+ ion beams extracted from alumino-silicate sources

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Prabir K.; Greenway, Wayne G.; Kwan, Joe W.

    2012-04-01

    A space-charge-limited beam with current densities (J) exceeding 1 mA/cm2 have been measured from lithium alumino-silicate ion sources at a temperature of ~1275 °C. At higher extraction voltages, the source appears to become emission limited with J ≥ 1.5 mA/cm2, and J increases weakly with the applied voltage. A 6.35 mm diameter source with an alumino-silicate coating, ≤0.25 mm thick, has a measured lifetime of ~40 h at ~1275 °C, when pulsed at 0.05 Hz and with pulse length of ~6 μs each. At this rate, the source lifetime was independent of the actual beam charge extracted due to the loss of neutral atoms at high temperature. Finally, the source lifetime increases with the amount of alumino-silicate coated on the emitting surface, and may also be further extended if the temperature is reduced between pulses.

  11. Source fabrication and lifetime for Li+ ion beams extracted from alumino-silicate sources

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Prabir K.; Greenway, Wayne G.; Kwan, Joe W

    2012-03-05

    A space-charge-limited beam with current densities (J) exceeding 1 mA/cm2 have been measured from lithium alumino-silicate ion sources at a temperature of ~1275 °C. At higher extraction voltages, the source appears to become emission limited with J ≥ 1.5 mA/cm2, and J increases weakly with the applied voltage. A 6.35 mm diameter source with an alumino-silicate coating, ≤0.25 mm thick, has a measured lifetime of ~40 h at ~1275 °C, when pulsed at 0.05 Hz and with pulse length of ~6 μs each. At this rate, the source lifetime was independent of the actual beam charge extracted due to the loss of neutral atoms at high temperature. Finally, the source lifetime increases with the amount of alumino-silicate coated on the emitting surface, and may also be further extended if the temperature is reduced between pulses.

  12. Lifetime of the 1s2s 3S1 metastable level in He-like S14+ measured with an electron beam ion trap

    Energy Technology Data Exchange (ETDEWEB)

    L?pez-Urrutia, J C; Beiersdorfer, P; Widmann, K

    2006-03-16

    A precision measurement of the lifetime of the lowest exited level of the He-like S{sup 14+} ion carried out at the Livermore EBIT-II electron beam ion trap yielded a value of (703 {+-} 4) ns. Our method extends the range of lifetime measurements accessible with electron beam ion traps into the nanosecond region and improves the accuracy of currently available data for this level by an order of magnitude.

  13. Modelling and Evaluation of Spectra in Beam Aided Spectroscopy

    Science.gov (United States)

    von Hellermann, M. G.; Delabie, E.; Jaspers, R.; Lotte, P.; Summers, H. P.

    2008-10-01

    The evaluation of active beam induced spectra requires advanced modelling of both active and passive features. Three types of line shapes are addressed in this paper: Thermal spectra representing Maxwellian distribution functions described by Gaussian-like line shapes, secondly broad-band fast ion spectra with energies well above local ion temperatures, and, finally, the narrow lines shapes of the equi-spaced Motion Stark multiplet (MSE) of excited neutral beam particles travelling through the magnetic field confining the plasma. In each case additional line shape broadening caused by Gaussian-like instrument functions is taken into account. Further broadening effects are induced by collision velocity dependent effective atomic rates where the observed spectral shape is the result of a convolution of emission rate function and velocity distribution function projected into the direction of observation. In the case of Beam Emission Spectroscopy which encompasses the Motional Stark features, line broadening is also caused by the finite angular spread of injected neutrals and secondly by a ripple in the acceleration voltage associated with high energy neutral beams.

  14. Evaluation of two-beam spectroscopy as a plasma diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Billard, B.D.

    1980-04-01

    A two-beam spectroscopy (TBS) system is evaluated theoretically and experimentally. This new spectroscopic technique uses correlations between components of emitted light separated by a small difference in angle of propagation. It is thus a non-perturbing plasma diagnostic which is shown to provide local (as opposed to line-of-sight averaged) information about fluctuations in the density of light sources within a plasma - information not obtainable by the usual spectroscopic methods. The present design is an improvement on earlier systems proposed in a thesis by Rostler.

  15. Column packings for high-performance liquid chromatography and positron annihilation lifetime spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sausa, O. [Institute of Physics of SAS, 84511 Bratislava (Slovakia)]. E-mail: fyzisaus@savba.sk; Kristiak, J. [Institute of Physics of SAS, 84511 Bratislava (Slovakia); Berek, D. [Polymer Institute of SAS, 84236 Bratislava (Slovakia); Iskrova, M. [Institute of Physics of SAS, 84511 Bratislava (Slovakia)

    2007-02-15

    Positron annihilation measurements as a function of temperature and the length of bonded alkyl groups have been carried out on silica gel samples. Silica gel samples were bare and bonded with alkyl group from C1 up to C18. The diameters of pores were deduced from the lifetime of trapped ortho-positronium (o-Ps), and it was found that o-Ps lifetime provides reasonable information on the pore sizes for both bare and alkyl bonded silica gels.

  16. Multiphoton Ionization Detection in Collinear Laser Spectroscopy of Isolde Beams

    CERN Multimedia

    2002-01-01

    The experiments using the multiphoton ionization technique have been continued in the beginning of 1990 with stable beam tests on the modified apparatus and with another radioactive beam time on Yb. Higher laser power and an increased vacuum in the ionization region (see figure) yielded a further gain in sensitivity, mainly due to the better suppression of the background ions produced in rest gas collisions. For even Yb isotopes we have now reached a detection efficiency of $\\epsilon$~=~1~x~10$^{-5}$ ions per incoming atom at a background count rate of 30~ions from a beam of 5~x~10$^9$. This sensitivity was high enough for spectroscopy on $^{157}$Yb, where the typical ISOLDE yield of 5~x~10$^7$Yb ions is covered by an isobaric contamination of more than 10$^{10}$ ions. Measurements have also been performed on $^{175}$Yb. These give the first precise value for the magnetic moment of this isotope, $\\mu$~=~0.766(8)$ mu _{N} $, which agrees rather well with the magnetic moment of the isotone $^{177}$Hf. The isoto...

  17. Fluorescence lifetime and UV-Vis spectroscopy to evaluate the interactions between quercetin and its yeast microcapsule.

    Science.gov (United States)

    Pham-Hoang, Bao-Ngoc; Winckler, Pascale; Waché, Yves

    2017-09-09

    Quercetin is a fragile bioactive compound. Several works have tried to preserve it by encapsulation but the form of encapsulation (mono- or supra-molecular structure, tautomeric form), though important for stability and bioavailability, remains unknown. The present work aims at developing a fluorescence lifetime technique to evaluate the structure of quercetin during encapsulation in a vector capsule that has already proven efficiency, yeast cells. Molecular stabilization was observed during a four-month storage period. The time-correlated single-photon counting (TCSPC) technique was used to evaluate the interaction between quercetin molecules and the yeast capsule. The various tautomeric forms, as identified by UV-Vis spectroscopy, resulted in various lifetimes in TCSPC, although they varied also with the buffer environment. Quercetin in buffer exhibited a three-to-four longer long time after 24 h (changing from 6-7 to 18-23 ns), suggesting an aggregation of molecules. In yeast microcapsules, the long-time population exhibited a longer lifetime (around 27 ns) from the beginning and concerned about 20% of molecules compared to dispersed quercetin. This shows that lifetime analysis can show the monomolecular instability of quercetin in buffer and the presence of interactions between quercetin molecules and their microcapsules. This article is protected by copyright. All rights reserved.

  18. Lifetime effects for high-resolution gamma-ray spectroscopy at relativistic energies and their implications for the RISING spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Doornenbal, P., E-mail: pieter@ribf.riken.j [Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Koeln (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Reiter, P. [Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Koeln (Germany); Grawe, H.; Saito, T. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Al-Khatib, A. [Helmholtz-Institut fuer Strahlen- und Kernphysik, Universitaet Bonn, 53115 Bonn (Germany); Banu, A.; Beck, T.; Becker, F. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Bednarczyk, P. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); The Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Krakow (Poland); Benzoni, G. [INFN Sezione di Milano, 20133 Milano (Italy); Bracco, A. [INFN Sezione di Milano, 20133 Milano (Italy); Dipartimento di Fisica, Universita di Milano, 20133 Milano (Italy); Buerger, A. [Helmholtz-Institut fuer Strahlen- und Kernphysik, Universitaet Bonn, 53115 Bonn (Germany); Caceres, L. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Departamento de Fisica Teorica, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Camera, F. [INFN Sezione di Milano, 20133 Milano (Italy); Dipartimento di Fisica, Universita di Milano, 20133 Milano (Italy); Chmel, S. [Helmholtz-Institut fuer Strahlen- und Kernphysik, Universitaet Bonn, 53115 Bonn (Germany); Crespi, F.C.L. [INFN Sezione di Milano, 20133 Milano (Italy); Dipartimento di Fisica, Universita di Milano, 20133 Milano (Italy); Geissel, H.; Gerl, J.; Gorska, M. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Grebosz, J. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Krakow (Poland)

    2010-02-01

    The lineshapes and peak position of Doppler corrected gamma-ray spectra from in-beam experiments at relativistic energies are investigated with respect to the intrinsic energy resolution of the employed detectors, the particles' velocities, and the photons' emission angle uncertainties at the moment of gamma-ray emission. The uncertainties in velocity and photon emission angle are dependent on the lifetime of the excited state. The impact of these two observables on the lineshape and energy resolution are studied for the RISING gamma-spectrometer by means of simulations and experimental results from a two-step fragmentation experiment at approx200MeV/u. Potential use of the distinct lineshape for lifetime determination is demonstrated for measured gamma-ray transitions.

  19. Age-hardening and precipitation phenomena in the Inconel-713C superalloy studied by means of positron lifetime spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Somoza, A.; Santos, G.; Ges, A. [Buenos Aires Univ. Nacional (Argentina). Facultad de Ciencias Exactas y Naturales; Versaci, R.; Plazaola, F.

    1999-07-16

    Specimens of the commercial superalloy Inconel-713C were heat treated by using isothermal artificial ageing treatments in order to obtain information on the process of precipitation of the {gamma}'-phase which is an intermetallic compound with a composition of Ni{sub 3}(Al, Ti) having a L1{sub 2}-ordered structure. The experimental information was basically obtained by means of positron lifetime spectroscopy and Vickers microhardness. In some specific cases, transmission electron microscopy was also used. From the positron results it was possible to analyze the influence of the homogenization and quenching procedures on the microstructure and to follow the coarsening of the smallest {gamma}'-particles during the very early stage of artificial ageing at 950 C. For long ageing times, when the overageing condition of the superalloy was clearly observed by a hardness decrease, the positron lifetime evolution reaches a stable maximum value and different annihilation mechanisms were discussed. (orig.)

  20. Time-Resolved Fluorescence Spectroscopy and Fluorescence Lifetime Imaging Microscopy for Characterization of Dendritic Polymer Nanoparticles and Applications in Nanomedicine

    Directory of Open Access Journals (Sweden)

    Alexander Boreham

    2016-12-01

    Full Text Available The emerging field of nanomedicine provides new approaches for the diagnosis and treatment of diseases, for symptom relief and for monitoring of disease progression. One route of realizing this approach is through carefully constructed nanoparticles. Due to the small size inherent to the nanoparticles a proper characterization is not trivial. This review highlights the application of time-resolved fluorescence spectroscopy and fluorescence lifetime imaging microscopy (FLIM for the analysis of nanoparticles, covering aspects ranging from molecular properties to particle detection in tissue samples. The latter technique is particularly important as FLIM allows for distinguishing of target molecules from the autofluorescent background and, due to the environmental sensitivity of the fluorescence lifetime, also offers insights into the local environment of the nanoparticle or its interactions with other biomolecules. Thus, these techniques offer highly suitable tools in the fields of particle development, such as organic chemistry, and in the fields of particle application, such as in experimental dermatology or pharmaceutical research.

  1. Symposium on atomic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    1979-01-01

    Topics covered by the conference include: fast beam spectroscopy; astrophysical and other spectra; highly ionized spectroscopy; complex spectra; rydberg levels; fine structure, hyperfine structure and isotope shift; lineshapes; lifetimes, oscillator strengths and Einstein coefficients; and spectroscopy with lasers. Abstracts of the conference papers are presented. (GHT)

  2. Effect of storage on microstructural changes of Carbopol polymers tracked by the combination of positron annihilation lifetime spectroscopy and FT-IR spectroscopy.

    Science.gov (United States)

    Szabó, Barnabás; Süvegh, Károly; Zelkó, Romána

    2011-09-15

    Different types of Carbopols are frequently applied excipients of various dosage forms. Depending on the supramolecular structure, their water sorption behaviour could significantly differ. The purpose of the present study was to track the supramolecular changes of two types of Carbopol polymers (Carbopol 71G and Ultrez 10NF) alone and in their physical mixture with a water-soluble drug, vitamin B(12), as a function of storage time. The combination of FT-IR spectroscopy, positron annihilation lifetime spectroscopy (PALS) and Doppler-broadening spectroscopy was applied to follow the effect of water uptake on the structural changes. Our results indicate that water-induced interactions between polymeric chains can be sensitively detected. This enables the prediction of stability of dosage forms in the course of storage.

  3. In-beam γ -ray spectroscopy of S-4238

    Science.gov (United States)

    Lunderberg, E.; Gade, A.; Bader, V.; Baugher, T.; Bazin, D.; Berryman, J. S.; Brown, B. A.; Hartley, D. J.; Recchia, F.; Stroberg, S. R.; Weisshaar, D.; Wimmer, K.

    2016-12-01

    The low-energy excitation level schemes of the neutron-rich S-4238 isotopes are investigated via in-beam γ -ray spectroscopy following the fragmentation of 48Ca and 46Ar projectiles on a 12C target at intermediate beam energies. Information on γ γ coincidences complemented by comparisons to shell-model calculations were used to construct level schemes for these neutron-rich nuclei. The experimental data are discussed in the context of large-scale shell-model calculations with the SDPF-MU effective interaction in the s d -p f shell. For the even-mass S isotopes, the evolution of the yrast sequence is explored as well as a peculiar change in decay pattern of the second 2+ states at N =26 . For the odd-mass 41S, a level scheme is presented that seems complete below 2.2 MeV and consistent with the predictions by the SDPF-MU shell-model Hamiltonian; this is a remarkable benchmark given the rapid shell and shape evolution at play in the S isotopes as the broken-down N =28 magic number is approached. Furthermore, the population of excited final states in projectile fragmentation is discussed.

  4. THE HYPHI PROJECT : HYPERNUCLEAR SPECTROSCOPY WITH STABLE HEAVY ION BEAMS AND RARE ISOTOPE BEAMS AT GSI AND FAIR

    NARCIS (Netherlands)

    Bianchin, S.; Achenbach, P.; Ajimura, S.; Borodina, O.; Fukuda, T.; Hoffmann, J.; Kavatsyuk, M.; Koch, K.; Koike, T.; Kurz, N.; Maas, F.; Minami, S.; Mizoi, Y.; Nagae, T.; Nakajima, D.; Okamura, A.; Ott, W.; Ozel, B.; Pochodzalla, J.; Rappold, C.; Saito, T. R.; Sakaguchi, A.; Sako, M.; Sekimoto, M.; Sugimura, H.; Takahashi, T.; Tamura, H.; Tanida, K.; Trautmann, W.

    2009-01-01

    The HypHI collaboration aims to perform a precise hypernuclear spectroscopy with stable heavy ion beams and rare isotope beams at GSI and FAIR in order to study hypernuclei at extreme isospin, especially neutron rich hypernuclei to look insight hyperon-nucleon interactions in the neutron rich medium

  5. Photon-induced positron annihilation lifetime spectroscopy using ultrashort laser-Compton-scattered gamma-ray pulses.

    Science.gov (United States)

    Taira, Y; Toyokawa, H; Kuroda, R; Yamamoto, N; Adachi, M; Tanaka, S; Katoh, M

    2013-05-01

    High-energy ultrashort gamma-ray pulses can be generated via laser Compton scattering with 90° collisions at the UVSOR-II electron storage ring. As an applied study of ultrashort gamma-ray pulses, a new photon-induced positron annihilation lifetime spectroscopy approach has been developed. Ultrashort gamma-ray pulses with a maximum energy of 6.6 MeV and pulse width of 2.2 ps created positrons throughout bulk lead via pair production. Annihilation gamma rays were detected by a BaF2 scintillator mounted on a photomultiplier tube. A positron lifetime spectrum was obtained by measuring the time difference between the RF frequency of the electron storage ring and the detection time of the annihilation gamma rays. We calculated the response of the BaF2 scintillator and the time jitter caused by the variation in the total path length of the ultrashort gamma-ray pulses, annihilation gamma rays, and scintillation light using a Monte Carlo simulation code. The positron lifetime for bulk lead was successfully measured.

  6. Two-photon excited fluorescence lifetime imaging and spectroscopy of melanins in vitro and in vivo

    Science.gov (United States)

    Krasieva, Tatiana B.; Stringari, Chiara; Liu, Feng; Sun, Chung-Ho; Kong, Yu; Balu, Mihaela; Meyskens, Frank L.; Gratton, Enrico; Tromberg, Bruce J.

    2013-03-01

    Changes in the amounts of cellular eumelanin and pheomelanin have been associated with carcinogenesis. The goal of this work is to develop methods based on two-photon-excited-fluorescence (TPEF) for measuring relative concentrations of these compounds. We acquire TPEF emission spectra (λex=1000 nm) of melanin in vitro from melanoma cells, hair specimens, and in vivo from healthy volunteers. We find that the pheomelanin emission peaks at approximately 615 to 625 nm and eumelanin exhibits a broad maximum at 640 to 680 nm. Based on these data we define an optical melanin index (OMI) as the ratio of fluorescence intensities at 645 and 615 nm. The measured OMI for the MNT-1 melanoma cell line is 1.6±0.22 while the Mc1R gene knockdown lines MNT-46 and MNT-62 show substantially greater pheomelanin production (OMI=0.5±0.05 and 0.17±0.03, respectively). The measured values are in good agreement with chemistry-based melanin extraction methods. In order to better separate melanin fluorescence from other intrinsic fluorophores, we perform fluorescence lifetime imaging microscopy of in vitro specimens. The relative concentrations of keratin, eumelanin, and pheomelanin components are resolved using a phasor approach for analyzing lifetime data. Our results suggest that a noninvasive TPEF index based on spectra and lifetime could potentially be used for rapid melanin ratio characterization both in vitro and in vivo.

  7. Correlation between Defect Concentration and Carrier Lifetime of GaAs Grown by Molecular Beam Epitaxy at Different Temperatures

    Science.gov (United States)

    Lin, Gong-Ru; Liu, Tze-An; Pan, Ci-Ling

    2001-11-01

    A pump-probe study of GaAs grown by molecular beam epitaxy at low temperatures (LT-GaAs) is performed. Ultrashort carrier lifetimes of the as-grown LT-GaAs increase from Schokley-Read-Hall model. The decreasing trend in the amplitudes of continuous-wave and transient reflectivities (Δ R/R) as a function of the growth temperature for the LT-GaAs is explained as an induced absorption caused by dense arsenic antisite defects. The sign of the transient Δ R/R reversed for LT-GaAs grown at 200°C. This is tentatively attributed to the band gap renormalization effect.

  8. To Test a Prototype of a Proton Lifetime Detector in a Neutrino Beam at the PS

    CERN Multimedia

    2002-01-01

    In order to test the performances of the calorimeter method in a nucleon lifetime experiment, a 3 ton prototype calorimeter made of iron and polystyrene scintillator sandwiches and of fine-grain counters has been designed by our collaboration. The energy and angular resolution will be tested by exposing this prototype to charged particles ($e, \\mu , \\pi$) in the 0.5 GeV/c range at Orsay and at CERN in Summer 1980. Since an unavoidable background to any experiment on nucleon decay consists of atmospheric neutrino events, which could in some cases simulate a nucleon decay, the knowledge of the configuration of such events in our detector is essential. It has been shown that the energy distribution of the $\

  9. Laser-frequency locking using light-pressure-induced spectroscopy in a calcium beam

    NARCIS (Netherlands)

    Mollema, A. K.; Wansbeek, L. W.; Willmann, L.; Jungmann, K.; Timmermans, R. G. E.; Hoekstra, R.

    We demonstrate a spectroscopy method that can be applied in an atomic beam, light-pressure-induced spectroscopy (LiPS). A simple pump and probe experiment yields a dispersivelike spectroscopy signal that can be utilized for laser frequency stabilization. The underlying principles are discussed and

  10. Applications and advances of positron beam spectroscopy: appendix a

    Energy Technology Data Exchange (ETDEWEB)

    Howell, R. H., LLNL

    1997-11-05

    Over 50 scientists from DOE-DP, DOE-ER, the national laboratories, academia and industry attended a workshop held on November 5-7, 1997 at Lawrence Livermore National Laboratory jointly sponsored by the DOE-Division of Materials Science, The Materials Research Institute at LLNL and the University of California Presidents Office. Workshop participants were charged to address two questions: Is there a need for a national center for materials analysis using positron techniques and can the capabilities at Lawrence Livermore National Laboratory serve this need. To demonstrate the need for a national center the workshop participants discussed the technical advantages enabled by high positron currents and advanced measurement techniques, the role that these techniques will play in materials analysis and the demand for the data. There were general discussions lead by review talks on positron analysis techniques, and their applications to problems in semiconductors, polymers and composites, metals and engineering materials, surface analysis and advanced techniques. These were followed by focus sessions on positron analysis opportunities in these same areas. Livermore now leads the world in materials analysis capabilities by positrons due to developments in response to demands of science based stockpile stewardship. There was a detailed discussion of the LLNL capabilities and a tour of the facilities. The Livermore facilities now include the worlds highest current beam of keV positrons, a scanning pulsed positron microprobe under development capable of three dimensional maps of defect size and concentration, an MeV positron beam for defect analysis of large samples, and electron momentum spectroscopy by positrons. This document is a supplement to the written summary report. It contains a complete schedule, list of attendees and the vuegraphs for the presentations in the review and focus sessions.

  11. Intracellular distribution of fluorescent copper and zinc bis(thiosemicarbazonato) complexes measured with fluorescence lifetime spectroscopy.

    Science.gov (United States)

    Hickey, James L; James, Janine L; Henderson, Clare A; Price, Katherine A; Mot, Alexandra I; Buncic, Gojko; Crouch, Peter J; White, Jonathan M; White, Anthony R; Smith, Trevor A; Donnelly, Paul S

    2015-10-05

    The intracellular distribution of fluorescently labeled copper and zinc bis(thiosemicarbazonato) complexes was investigated in M17 neuroblastoma cells and primary cortical neurons with a view to providing insights into the neuroprotective activity of a copper bis(thiosemicarbazonato) complex known as Cu(II)(atsm). Time-resolved fluorescence measurements allowed the identification of the Cu(II) and Zn(II) complexes as well as the free ligand inside the cells by virtue of the distinct fluorescence lifetime of each species. Confocal fluorescent microscopy of cells treated with the fluorescent copper(II)bis(thiosemicarbazonato) complex revealed significant fluorescence associated with cytoplasmic puncta that were identified to be lysosomes in primary cortical neurons and both lipid droplets and lysosomes in M17 neuroblastoma cells. Fluorescence lifetime imaging microscopy confirmed that the fluorescence signal emanating from the lipid droplets could be attributed to the copper(II) complex but also that some degree of loss of the metal ion led to diffuse cytosolic fluorescence that could be attributed to the metal-free ligand. The accumulation of the copper(II) complex in lipid droplets could be relevant to the neuroprotective activity of Cu(II)(atsm) in models of amyotrophic lateral sclerosis and Parkinson's disease.

  12. Avalanche photodiode based detector for beam emission spectroscopy.

    Science.gov (United States)

    Dunai, D; Zoletnik, S; Sárközi, J; Field, A R

    2010-10-01

    An avalanche photodiode based (APD) detector for the visible wavelength range was developed for low light level, high frequency beam emission spectroscopy (BES) experiments in fusion plasmas. This solid state detector has higher quantum efficiency than photomultiplier tubes, and unlike normal photodiodes, it has internal gain. This paper describes the developed detector as well as the noise model of the electronic circuit. By understanding the noise sources and the amplification process, the optimal amplifier and APD reverse voltage setting can be determined, where the signal-to-noise ratio is the highest for a given photon flux. The calculations are compared to the absolute calibration results of the implemented circuit. It was found that for a certain photon flux range, relevant for BES measurements (≈10(8)-10(10) photons/s), the new detector is superior to both photomultipliers and photodiodes, although it does not require cryogenic cooling of any component. The position of this photon flux window sensitively depends on the parameters of the actual experimental implementation (desired bandwidth, detector size, etc.) Several detector units based on these developments have been built and installed in various tokamaks. Some illustrative results are presented from the 8-channel trial BES system installed at Mega-Ampere Spherical Tokamak (MAST) and the 16-channel BES system installed at the Torus Experiment for Technology Oriented Research (TEXTOR).

  13. Early stages of superplasticity and positron lifetime spectroscopy in an Al-Mg-Cu alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ayciriex, M.D.; Romero, R.; Somoza, A. [Universidad Nacional del Centro de la Provincia de Buenos Aires (Argentina). Instituto de Fisica de Materiales Tandil

    1996-07-01

    In the present paper, by using positron lifetime technique, a careful study is carried out to analyze the microstructural changes induced on samples of an Al-based commercial alloy (Al-Mg-Cu-Mn-Cr) by superplastic deformation in the early stages of superplastic behavior of the alloy (strain range from 0.2% to 100%). These results are compared with those obtained on specimens only heat treated at the same temperature and for a time equivalent to the elapsed time during each tensile test, in order to evaluate the thermal contribution to the microstructural changes induced during the superplastic deformation process. Moreover, the positron results were linked with the microstructural evolution of the samples followed by means of optical microscopy and Vickers microhardness technique.

  14. RFQ beam cooler and buncher for collinear laser spectroscopy of rare isotopes

    Science.gov (United States)

    Barquest, B. R.; Bollen, G.; Mantica, P. F.; Minamisono, K.; Ringle, R.; Schwarz, S.; Sumithrarachchi, C. S.

    2017-09-01

    A radiofrequency quadrupole (RFQ) ion beam cooler and buncher has been developed to deliver bunched beams with low transverse emittance, energy spread, and time spread to the BECOLA collinear laser spectroscopy system at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. The beam cooler and buncher contains new features which enhance performance, especially for high count rate beams, as well as simplifying construction, maintenance, and operation. The transverse emittance, energy spread, and time spread of the bunched beam, as well as buncher efficiency are reported, showcasing the capabilities of the BECOLA facility to perform collinear laser spectroscopy measurements with bunched rare isotope beams at NSCL and at the future Facility for Rare Isotope Beams (FRIB).

  15. Probing Cu Diffusion Barrier Layers on Porous Low-Dielectric-Constant Films by Posireonium Annihilation Lifetime Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    HU Yi-Fan; SUN Jia-Ning; Gidley D.W.

    2005-01-01

    @@ Two kinds of Cu diffusion barrier layers, sealedfilms and capped fi1ms, on nanoporous low-dielectric-constant filmsare investigated by positronium annihilation lifetime spectroscopy (PALS). We have found that the minimumthickness of Ta to form an effective diffusion barrier is affected by the pore size. The films with large poresrequire thick barrier layers to form effective diffusion barriers. In addition, a possible ultra-thin diffusion barrier,i.e. a plasma-induced densification layer, has also been investigated. The PALS data confirm that a porouslow-dielectric-constant thin film can be shrunk by exposure to plasma. This shrinkage is confined to a surfacelayer of collapsed pores and forms a dense layer. The dense layer tends to behave as Ps (positronium) diffusionbarriers. Indeed, the controlled thin "skin" layer could prevent Cu diffusion into the underlying dielectrics.

  16. Influence of substrate heating on excited state generation rates and lifetime in organic solar cells studied by photoinduced absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ziehlke, Hannah; Koerner, Christian; Leo, Karl; Riede, Moritz [IAPP, TU Dresden (Germany); Fitzner, Roland; Reinold, Egon; Baeuerle, Peter [Institut fuer Organische Chemie II und Neue Materialien, Univ. Ulm (Germany)

    2011-07-01

    The performance of organic solar cells crucially depends on the separation of photogenerated excitons into free charge carriers. The dissociation process is sensitively influenced by the nanomorphology of donor (D) and acceptor (A) phases in the photoactive blend layer. Closed percolation paths have to be present such that the created charges are able to leave the blend layer, but also the crystallinity of the D- and the A-phase influence exciton dissociation on a molecular scale. Substrate heating during the vacuum deposition of the active layer is a method to influence the thin film morphology that can lead to improved device performance. We here characterize dicyanovinyl capped quinquethiophenes (D) deposited on substrates at different temperatures (30 and 80 C). Photoinduced absorption spectroscopy (PIA) is used to determine excited state lifetimes and generation rates.We find that efficient charge separation occurs in blends with C{sub 60} (A) and identify the observed excited states as donor cations and triplet excitons. Heating the substrate results in an increased lifetime of the donor cation on the one hand and a decrease in the generation rate of cations on the other hand. The PIA results are complemented by solar cell devices as well as morphological studies.

  17. Measurement of the lifetime of Pb$^{52+}$, Pb$^{53+}$ and Pb$^{54+}$ beams at 4.2 MeV per nucleon subject to electron cooling

    CERN Document Server

    Baird, S A; Carli, Christian; Chanel, M; Lefèvre, P; Ley, R; MacCaferri, R; Maury, S; Meshkov, I N; Möhl, D; Molinari, G; Motsch, F; Mulder, H; Tranquille, G; Varenne, F

    1995-01-01

    By measuring the lifetime of stored beams, the recombination of the ions with cooling electrons was investigated. Rates found are larger than expected for radiative electron capture and significantly higher for Pb53+ than for Pb54+ and Pb52+. These results are important for the design of the lead ion injection system for the Large Hadron Collider and for recombination theories.

  18. Hypernuclear Spectroscopy with Stable Heavy Ion Beams and Rare-isotope Beams:HypHI Project at GSI and FAIR

    Institute of Scientific and Technical Information of China (English)

    T.R.Saito

    2009-01-01

    The international HypHI collaboration proposes to perform hypernuclear spectroscopy with stable heavy ion beams and rare isotope beams at GSI and FAIR in order to study neutron and proton rich hypernuclei and to measure directly hypernuclear magnetic moments for the first time.The project is divided into four phases.In the first Phase 0 experiment,the feasibility of precise hypernuclear spectroscopy with heavy ion beams will be demonstrated by observing π~- decay channels of ~e_ΛH,~4_ΛH and ~5_ΛHe with ~6Li projectiles at 2 AGeV impinging on a ~(12)C target.In the later Phases 1 through 3,studies of proton and neutron rich hypernuclei,direct measurements of hypernuclear magnetic moments and the spectroscopy of hypernuclei toward the nucleon drip-lines are planned.

  19. Spectroscopy and lifetime measurements of states in $^{76}$Kr populated in $^{76}$Rb decay

    CERN Document Server

    Giannatiempo, A; Perego, A; Sona, P; Mach, H; Fogelberg, B; García-Borge, M J; Tengblad, O; Fraile-Prieto, L M; Aas, A J; Gulda, K; CERN. Geneva

    2005-01-01

    The properties of the excited states of $^{76}$Kr, populated in the decay of $^{76}$Rb produced at ISOLDE isotopic separator, have been investigated by using K-conversion electron, $\\gamma$-ray, and $\\gamma\\gamma$ coincidence measurements. The lifetimes of several levels have been measured by means of the Advanced Time-Delayed $\\beta\\gamma\\gamma (t)$ method. The identification of 19 new levels and 55 transitions and the information deduced on spin and/or parity of the observed states from K-conversion coefficients, log ft values and decay properties have led to an improved knowledge of the level scheme. In particular, six 1$^-$ states have been definitely identified and $J^{\\pi} =2^{-}$ has been assigned to the 2227 keV level, on which a band proposed to have negative-parity and even-spin had been previously observed. The strengths of the $E$0 and $E$2 transitions de-exciting the 0$^{+}_{2}$ and 0$^{+}_{3}$ states (the latter is here identified with the state at 1598 keV) have been measured. The experimental ...

  20. Electrochemical impedance spectroscopy investigation on the clinical lifetime of ProTaper rotary file system.

    Science.gov (United States)

    Penta, Virgil; Pirvu, Cristian; Demetrescu, Ioana

    2014-01-01

    The main objective of the current paper is to show that electrochemical impedance spectroscopy (EIS) could be a method for evaluating and predicting of ProTaper rotary file system clinical lifespan. This particular aspect of everyday use of the endodontic files is of great importance in each dental practice and has profound clinical implications. The method used for quantification resides in the electrochemical impedance spectroscopy theory and has in its main focus the characteristics of the surface titanium oxide layer. This electrochemical technique has been adapted successfully to identify the quality of the Ni-Ti files oxide layer. The modification of this protective layer induces changes in corrosion behavior of the alloy modifying the impedance value of the file. In order to assess the method, 14 ProTaper sets utilized on different patients in a dental clinic have been submitted for testing using EIS. The information obtained in regard to the surface oxide layer has offered an indication of use and proves that the said layer evolves with each clinical application. The novelty of this research is related to an electrochemical technique successfully adapted for Ni-Ti file investigation and correlation with surface and clinical aspects.

  1. Electrochemical Impedance Spectroscopy Investigation on the Clinical Lifetime of ProTaper Rotary File System

    Science.gov (United States)

    Pirvu, Cristian; Demetrescu, Ioana

    2014-01-01

    The main objective of the current paper is to show that electrochemical impedance spectroscopy (EIS) could be a method for evaluating and predicting of ProTaper rotary file system clinical lifespan. This particular aspect of everyday use of the endodontic files is of great importance in each dental practice and has profound clinical implications. The method used for quantification resides in the electrochemical impedance spectroscopy theory and has in its main focus the characteristics of the surface titanium oxide layer. This electrochemical technique has been adapted successfully to identify the quality of the Ni-Ti files oxide layer. The modification of this protective layer induces changes in corrosion behavior of the alloy modifying the impedance value of the file. In order to assess the method, 14 ProTaper sets utilized on different patients in a dental clinic have been submitted for testing using EIS. The information obtained in regard to the surface oxide layer has offered an indication of use and proves that the said layer evolves with each clinical application. The novelty of this research is related to an electrochemical technique successfully adapted for Ni-Ti file investigation and correlation with surface and clinical aspects. PMID:24605336

  2. Electrochemical Impedance Spectroscopy Investigation on the Clinical Lifetime of ProTaper Rotary File System

    Directory of Open Access Journals (Sweden)

    Virgil Penta

    2014-01-01

    Full Text Available The main objective of the current paper is to show that electrochemical impedance spectroscopy (EIS could be a method for evaluating and predicting of ProTaper rotary file system clinical lifespan. This particular aspect of everyday use of the endodontic files is of great importance in each dental practice and has profound clinical implications. The method used for quantification resides in the electrochemical impedance spectroscopy theory and has in its main focus the characteristics of the surface titanium oxide layer. This electrochemical technique has been adapted successfully to identify the quality of the Ni-Ti files oxide layer. The modification of this protective layer induces changes in corrosion behavior of the alloy modifying the impedance value of the file. In order to assess the method, 14 ProTaper sets utilized on different patients in a dental clinic have been submitted for testing using EIS. The information obtained in regard to the surface oxide layer has offered an indication of use and proves that the said layer evolves with each clinical application. The novelty of this research is related to an electrochemical technique successfully adapted for Ni-Ti file investigation and correlation with surface and clinical aspects.

  3. Mixed IR/Vis two-dimensional spectroscopy: chemical exchange beyond the vibrational lifetime and sub-ensemble selective photochemistry.

    Science.gov (United States)

    van Wilderen, Luuk J G W; Messmer, Andreas T; Bredenbeck, Jens

    2014-03-03

    Two-dimensional exchange spectroscopy (2D EXSY) is a powerful method to study the interconversion (chemical exchange) of molecular species in equilibrium. This method has recently been realized in femtosecond 2D-IR spectroscopy, dramatically increasing the time resolution. However, current implementations allow the EXSY signal (and therefore the chemical process of interest) only to be tracked during the lifetime (T1 ) of the observed spectroscopic transition. This is a severe limitation, as typical vibrational T1 are only a few ps. An IR/Vis pulse sequence is presented that overcomes this limit and makes the EXSY signal independent of T1 . The same pulse sequence allows to collect time-resolved IR spectra after electronic excitation of a particular chemical species in a mixture of species with strongly overlapping UV/Vis spectra. Different photoreaction pathways and dynamics of coexisting isomers or of species involved in different intermolecular interactions can thus be revealed, even if the species cannot be isolated because they are in rapid equilibrium.

  4. HYPERNUCLEAR SPECTROSCOPY WITH HEAVY ION BEAMS : THE HypHI PROJECT AT GSI AND FAIR

    NARCIS (Netherlands)

    Saito, T. R.; Bianchin, S.; Borodina, O.; Hoffmann, J.; Koch, K.; Kurz, N.; Maas, F.; Minami, S.; Nakajima, D.; Ott, W.; Oezel, B.; Rappold, C.; Schmidt, C.; Trautmann, W.; Traeger, M.; Voltz, S.; Achenbach, P.; Pochodzalla, J.; Sekimoto, M.; Takahashi, T.; Kavatsyuk, M.; Hayashi, Y.; Hiraiwa, T.; Moritsu, M.; Nagae, T.; Okamura, A.; Sako, M.; Sugimura, H.; Tanida, K.; Fukuda, T.; Mizoi, Y.; Ajimura, S.; Mochizuki, T.; Sakaguchi, A.; Koike, T.; Tamura, H.

    2010-01-01

    The HypHI experiment for precise hypernuclear spectroscopy with induced reactions of stable heavy ion beams and rare isotope beams is currently under preparation at GSI. The main goal of the HypHI project is to study neutron and proton rich hypernuclei and to measure directly hypernuclear magnetic m

  5. Physical Selectivity of Molecularly Imprinted polymers evaluated through free volume size distributions derived from Positron Lifetime Spectroscopy

    Science.gov (United States)

    Pasang, T.; Ranganathaiah, C.

    2015-06-01

    The technique of imprinting molecules of various sizes in a stable structure of polymer matrix has derived multitudes of applications. Once the template molecule is extracted from the polymer matrix, it leaves behind a cavity which is physically (size and shape) and chemically (functional binding site) compatible to the particular template molecule. Positron Annihilation Lifetime Spectroscopy (PALS) is a well known technique to measure cavity sizes precisely in the nanoscale and is not being used in the field of MIPs effectively. This method is capable of measuring nanopores and hence suitable to understand the physical selectivity of the MIPs better. With this idea in mind, we have prepared molecular imprinted polymers (MIPs) with methacrylicacid (MAA) as monomer and EGDMA as cross linker in different molar ratio for three different size template molecules, viz. 4-Chlorophenol (4CP)(2.29 Å), 2-Nephthol (2NP) (3.36 Å) and Phenolphthalein (PP) (4.47Å). FTIR and the dye chemical reactions are used to confirm the complete extraction of the template molecules from the polymer matrix. The free volume size and its distribution have been derived from the measured o-Ps lifetime spectra. Based on the free volume distribution analysis, the percentage of functional cavities for the three template molecules are determined. Percentage of functional binding cavities for 4-CP molecules has been found out to be 70.2% and the rest are native cavities. Similarly for 2NP it is 81.5% and nearly 100% for PP. Therefore, PALS method proves to be very precise and accurate for determining the physical selectivity of MIPs.

  6. The HypHI project: Hypernuclear spectroscopy with stable heavy ion beams and rare isotope beams at GSI and FAIR

    CERN Document Server

    Bianchin, S; Ajimura, S; Borodina, O; Fukuda, T; Hoffmann, J; Kavatsyuk, M; Koch, K; Koike, T; Kurz, N; Maas, F; Minami, S; Mizoi, Y; Nagae, T; Nakajima, D; Okamura, A; Ott, W; Özel, B; Pochodzalla, J; Rappold, C; Saito, T R; Sakaguchi, A; Sako, M; Sekimoto, M; Sugimura, H; Takahashi, T; Tamura, H; Tanida, K; Trautmann, W

    2008-01-01

    The HypHI collaboration aims to perform a precise hypernuclear spectroscopy with stable heavy ion beams and rare isotope beams at GSI and fAIR in order to study hypernuclei at extreme isospin, especially neutron rich hypernuclei to look insight hyperon-nucleon interactions in the neutron rich medium, and hypernuclear magnetic moments to investigate baryon properties in the nuclei. We are currently preparing for the first experiment with $^6$Li and $^{12}$C beams at 2 AGeV to demonstrate the feasibility of a precise hypernuclear spectroscopy by identifying $^{3}_{\\Lambda}$H, $^{4}_{\\Lambda}$H and $^{5}_{\\Lambda}$He. The first physics experiment on these hypernuclei is planned for 2009. In the present document, an overview of the HypHI project and the details of this first experiment will be discussed.

  7. Quasi first-order Hermite Gaussian beam for enhanced sensitivity in Sagnac interferometer photothermal deflection spectroscopy.

    Science.gov (United States)

    Shiokawa, Naoyuki; Tokunaga, Eiji

    2016-05-30

    The detection sensitivity of a Sagnac interferometer photothermal deflection spectroscopy was enhanced by changing the probe beam pattern from zero-order to a quasi-first-order Hermite Gaussian (QHG) beam. The nature of the higher order HG mode, where the beam pattern is preserved during propagation with an increased field gradient, is utilized to enhance the measurement sensitivity. In this spectroscopy, the lateral beam deflection due to the photothermal effect is sensitively detected as a change in the interference light intensity. The change in intensity is amplified due to the higher field gradient of the QHG(1,0) beam at the photodetector. This amplification effect was both numerically and experimentally demonstrated to obtain twofold improvement in the signal-to-noise ratio.

  8. INVESTIGATION OF MICROSTRUCTURE AND CONDUCTIVE MECHANISM OF HIGH DENSITY POLYETHYLENE/CARBON BLACK PARTICLE COMPOSITE BY POSITRON ANNIHILATION LIFETIME SPECTROSCOPY

    Institute of Scientific and Technical Information of China (English)

    Yang-mei Fan; Xian-fenga Zhang; Bang-jiao Ye; Xian-yi Zhou; Hui-min Weng; Jiang-feng Du; Rong-dian Han; Shao-jin Jia; Zhi-cheng Zhang

    2002-01-01

    The microstmcture and conductive mechanism of high density polyethylene/carbon black (HDPE/CB) composite were investigated by positron annihilation lifetime spectroscopy (PALS). The PALS were measured in two series of samples,one with various CB contents in the composites and the other with various γ-irradiation doses in HDPE/CB composite containing 20 wt% CB. It was found that CB particles distribute in the amorphous regions, the CB critical content value in HDPE/CB composite is about 16.7 wt% and the suitable γ-irradiation dose for improving the conductive behavior of HDPE/CB composite is about 20 Mrad. The result observed for the second set of samples suggests that γ-irradiation causes not only cross-linking in amorphous regions but also destruction of the partial crystalline structure. Therefore, a suitable irradiation dose, about 20 Mrad, can induce sufficient cross-linking in the amorphous regions without enhancing the decomposition of crystalline structure, so that the positive temperature coefficient (PTC) effect remains while the negative temperature coefficient (NTC) effect is suppressed. A new interpretation of the conductive mechanism, which might provide a more detailed explanation of the PTC effect and the NTC effect has been proposed.

  9. Center for Fluorescence Spectroscopy: advanced studies of fluorescence dynamics, lifetime imaging, clinical sensing, two-photon excitation, and light quenching

    Science.gov (United States)

    Lakowicz, Joseph R.; Malak, Henryk M.; Gryczynski, Ignacy; Szmacinski, Henryk; Kusba, Jozef; Akkaya, Engin; Terpetschnig, Ewald A.; Johnson, Michael L.

    1994-08-01

    The Center for Fluorescence Spectroscopy (CFS) is a multi-user facility providing state of the art time-resolved fluorescence instrumentation and software for scientists, whose research can be enhanced by such experimental data. The CFS is a national center, supported by the National Center for Research Resources Division of the National Institutes of Health, and in part by the National Science Foundation. Both time-domain (TD) and frequency- domain (FD) measurements (10 MHz to 10 Ghz) are available, with a wide range of excitation and emission wavelengths (UV to NIR). The data can be used to recover distances and site-to-site diffusion in protein, interactions between macromolecules, accessibility of fluorophores to quenchers, and the dynamic properties of proteins, membranes and nucleic acids. Current software provides for analysis of multi-exponential intensity and anisotropy decays, lifetime distribution, distance distributions for independent observation of fluorescence donors and acceptors, transient effects in collisional quenching, phase-modulation spectra and time-resolved emission spectra. Most programs provide for global analysis of multiple data sets obtained under similar experimental conditions. Data can be analyzed on-site by connection with the CFS computers through the internet. During six years of operation we have established scientific collaborations with over 30 academic and industrial groups in the United States. These collaborations have resulted in 63 scientific papers.

  10. Single-Beam Coherent Raman Spectroscopy and Microscopy via Spectral Notch Shaping

    CERN Document Server

    Katz, Ori; Grinvald, Eran; Silberberg, Yaron

    2010-01-01

    Raman spectroscopy is one of the key techniques in the study of vibrational modes and molecular structures. In Coherent Anti-Stokes Raman Scattering (CARS) spectroscopy, a molecular vibrational spectrum is resolved via the third-order nonlinear interaction of pump, Stokes and probe photons, typically using a complex experimental setup with multiple beams and laser sources. Although CARS has become a widespread technique for label-free chemical imaging and detection of contaminants, its multi-source, multi-beam experimental implementation is challenging. In this work we present a simple and easily implementable scheme for performing single-beam CARS spectroscopy and microscopy using a single femtosecond pulse, shaped by a tunable narrowband notch filter. As a substitute for multiple sources, the single broadband pulse simultaneously provides the pump, Stokes and probe photons, exciting a broad band of vibrational levels. High spectroscopic resolution is obtained by utilizing a tunable spectral notch, shaped wi...

  11. LOW ENERGY BEAM-GAS SPECTROSCOPY OF HIGHLY IONISED ATOMS

    OpenAIRE

    Desesquelles, J.; DENIS A.; Druetta, M.; Martin, S.

    1989-01-01

    Features of low energy beam-gas spectroscopic source are reviewed and compared to those of other light sources. Measurement techniques are surveyed. They include the study of wavelength of heavy multiply charged ions in visible and u.v. ranges from normal excited states, doubly excited states, high n levels and doubly excited Rydberg levels.

  12. A compact atomic beam based system for Doppler-free laser spectroscopy of Strontium atoms

    OpenAIRE

    Verma, Gunjan; Vishwakarma, Chetan; Dharmadhikari, C. V.; Rapol, Umakant D.

    2016-01-01

    We report the construction of a simple, light weight and compact atomic beam spectroscopy cell for Strontium atoms. The cell is built using glass blowing technique and includes a simple Titanium Sublimation Pump for active pumping of the residual and background gases to maintain ultra-high vacuum. Commercially available and electrically heated dispenser source is used to generate the beam of Sr atoms. We perform spectroscopy on the $5s^2\\ ^1S_0\\longrightarrow 5s\\ 5p\\ ^1P_1$ transition to obta...

  13. Development of a Multi-modal Tissue Diagnostic System Combining High Frequency Ultrasound and Photoacoustic Imaging with Lifetime Fluorescence Spectroscopy

    Science.gov (United States)

    Sun, Yang; Stephens, Douglas N.; Park, Jesung; Sun, Yinghua; Marcu, Laura; Cannata, Jonathan M.; Shung, K. Kirk

    2010-01-01

    We report the development and validate a multi-modal tissue diagnostic technology, which combines three complementary techniques into one system including ultrasound backscatter microscopy (UBM), photoacoustic imaging (PAI), and time-resolved laser-induced fluorescence spectroscopy (TR-LIFS). UBM enables the reconstruction of the tissue microanatomy. PAI maps the optical absorption heterogeneity of the tissue associated with structure information and has the potential to provide functional imaging of the tissue. Examination of the UBM and PAI images allows for localization of regions of interest for TR-LIFS evaluation of the tissue composition. The hybrid probe consists of a single element ring transducer with concentric fiber optics for multi-modal data acquisition. Validation and characterization of the multi-modal system and ultrasonic, photoacoustic, and spectroscopic data coregistration were conducted in a physical phantom with properties of ultrasound scattering, optical absorption, and fluorescence. The UBM system with the 41 MHz ring transducer can reach the axial and lateral resolution of 30 and 65 μm, respectively. The PAI system with 532 nm excitation light from a Nd:YAG laser shows great contrast for the distribution of optical absorbers. The TR-LIFS system records the fluorescence decay with the time resolution of ~300 ps and a high sensitivity of nM concentration range. Biological phantom constructed with different types of tissues (tendon and fat) was used to demonstrate the complementary information provided by the three modalities. Fluorescence spectra and lifetimes were compared to differentiate chemical composition of tissues at the regions of interest determined by the coregistered high resolution UBM and PAI image. Current results demonstrate that the fusion of these techniques enables sequentially detection of functional, morphological, and compositional features of biological tissue, suggesting potential applications in diagnosis of tumors

  14. Direct Vpr-Vpr Interaction in Cells monitored by two Photon Fluorescence Correlation Spectroscopy and Fluorescence Lifetime Imaging

    Directory of Open Access Journals (Sweden)

    Mély Yves

    2008-09-01

    Full Text Available Abstract Background The human immunodeficiency virus type 1 (HIV-1 encodes several regulatory proteins, notably Vpr which influences the survival of the infected cells by causing a G2/M arrest and apoptosis. Such an important role of Vpr in HIV-1 disease progression has fuelled a large number of studies, from its 3D structure to the characterization of specific cellular partners. However, no direct imaging and quantification of Vpr-Vpr interaction in living cells has yet been reported. To address this issue, eGFP- and mCherry proteins were tagged by Vpr, expressed in HeLa cells and their interaction was studied by two photon fluorescence lifetime imaging microscopy and fluorescence correlation spectroscopy. Results Results show that Vpr forms homo-oligomers at or close to the nuclear envelope. Moreover, Vpr dimers and trimers were found in the cytoplasm and in the nucleus. Point mutations in the three α helices of Vpr drastically impaired Vpr oligomerization and localization at the nuclear envelope while point mutations outside the helical regions had no effect. Theoretical structures of Vpr mutants reveal that mutations within the α-helices could perturb the leucine zipper like motifs. The ΔQ44 mutation has the most drastic effect since it likely disrupts the second helix. Finally, all Vpr point mutants caused cell apoptosis suggesting that Vpr-mediated apoptosis functions independently from Vpr oligomerization. Conclusion We report that Vpr oligomerization in HeLa cells relies on the hydrophobic core formed by the three α helices. This oligomerization is required for Vpr localization at the nuclear envelope but not for Vpr-mediated apoptosis.

  15. Positron annihilation lifetime spectroscopy study on the structural relaxation of phenylmethylsiloxane-modified epoxy hybrids at different aging temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Chia-Wen [Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan (China); Material and Chemical Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan (China); Ma, Chen-Chi M., E-mail: ccma@che.nthu.edu.tw [Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan (China); Tan, Chung-Sung [Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan (China); Li, Hsun-Tien [Material and Chemical Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan (China)

    2015-07-15

    The cured network conformations and structural relaxation behaviours of the diglycidyl ether of bisphenol A (DGEBA)-methylhexahydrophthalic anhydride (MHHPA) modified with phenylmethylsiloxane-modified epoxy (PMSE) at different aging temperatures were studied using dynamic mechanical analysis (DMA) and positron annihilation lifetime spectroscopy (PALS). The DMA results revealed that the cured PMSE network can insert into the cured DGEBA network to form interpenetrating polymer networks (IPNs). The structural relaxation behaviours of DGEBA–PMSE-0.4 produced using DGEBA, PMSE, and MHHPA at a ratio of 0.6:0.4:1 by equivalent weight were studied using PALS at 150 °C and 55 °C. The aging-induced free volume relaxation parameters of DGEBA–PMSE-0.4 at 150 °C and 55 °C were investigated using the double additive exponential model and the Kohlrausch–Williams–Watts exponential model. For double additive exponential model, only one relaxation time (ζ) of 584.5 h was found at 150 °C; By contrast, there were two separate relaxation times of 37.4 h (ζ{sub 1}) and 753.6 h (ζ{sub 2}) at 55 °C. The ζ{sub 1} of the IPNs hybrid can be attributed to the network relaxation of PMSE, and the ζ{sub 2} can be attributed to the network relaxation of DGEBA at 55 °C. The results suggested the double additive exponential model can effectively predict DGEBA–PMSE hybrid relaxation behaviours. - Highlights: • The cured network conformations of DGEBA–PMSE hybrids were studied using DMA. • The structural relaxation behaviours of DGEBA–PMSE hybrids were studied using PALS. • The cured DGEBA–PMSE hybrids were interpenetrating polymer networks (IPNs). • PALS studies provided a quantitative demonstration of relaxation behaviours. • Double additive exponential model effectively predicted the relaxation times of hybrids.

  16. Measurement of Moments and Radii of Light Nuclei by Collinear Fast-Beam Laser Spectroscopy and $\\beta$-NMR Spectroscopy

    CERN Multimedia

    Marinova, K P

    2002-01-01

    Nuclear Moments and radii of light unstable isotopes are investigated by applying different high-sensitivity and high-resolution techniques based on collinear fast-beam laser spectroscopy. A study of nuclear structure in the sd shell is performed on neon isotopes in the extended chain of $^{17-28}$Ne, in particular on the proton-halo candidate $^{17}$Ne. Measurements of hyperfine structure and isotope shift have become possible by introducing an ultra-sensitive non-optical detection method which is based on optical pumping, state-selective collisional ionization and $\\beta$-activity counting. The small effect of nuclear radii on the optical isotope shifts of light elements requires very accurate measurements. The errors are dominated by uncertainties of the Doppler shifts which are conventionally determined from precisely measured acceleration voltages. These uncertainties are removed by measuring the beam energy with simultaneous excitation of two optical lines in parallel / antiparallel beam configuration. ...

  17. Absorption spectroscopy with sub-angstrom beams: ELS in STEM

    Science.gov (United States)

    Spence, John C. H.

    2006-03-01

    Electron-energy loss spectroscopy (EELS) performed using a modern transmission scanning electron microscope (STEM) now offers sub-nanometre spatial resolution and an energy resolution down to 200 meV or less, in favourable cases. The absorption spectra, which probe empty states, cover the soft x-ray region and may be obtained under conditions of well-defined momentum transfer (angle-resolved), providing a double projection onto crystallographic site and symmetry within the density of states. By combining the very high brightness of field-emission electron sources (brighter than a synchrotron) with the high cross-section of electron scattering, together with parallel detection (not possible with scanning x-ray absorption spectroscopy), a form of spectroscopy ideally suited to the study of nanostructures, interfacial states and defects in materials is obtained with uniquely high spatial resolution. We review the basic theory, the relationship of EELS to optical properties and the dielectric response function, the removal of multiple scattering artefacts and channelling effects. We consider applications in the light of recent developments in aberration corrector and electron monochromator design. Examples are cited of inner-shell spectra obtained from individual atoms within thin crystals, of the detection of interfacial electronic states in semiconductors, of inner-shell near edge structure mapped with sub-nanometre spatial resolution in glasses and of spectra obtained from individual carbon nanotubes, amongst many others.

  18. Investigations into the free-volume changes within starch/plasticizer/nanoclay systems using Positron Annihilation Lifetime Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Huihua, E-mail: h.liu@federation.edu.au [School of Health Sciences, Federation University Australia, Ballarat, Vic (Australia); Chaudhary, Deeptangshu, E-mail: deepc@ers.com.au [ERS Environmental Risk Solutions PTY LTD, Perth, WA (Australia); Campbell, Colin, E-mail: colin.campbell@anu.edu.au [ARC Centre of Excellence for Antimatter-Matter Studies (CAMS), Research School of Physics and Engineering, Australian National University, Canberra (Australia); Roberts, Jason, E-mail: jxr107@physics.anu.edu.au [ARC Centre of Excellence for Antimatter-Matter Studies (CAMS), Research School of Physics and Engineering, Australian National University, Canberra (Australia); Buckman, Stephen, E-mail: stephen.buckman@anu.edu.au [ARC Centre of Excellence for Antimatter-Matter Studies (CAMS), Research School of Physics and Engineering, Australian National University, Canberra (Australia); Sullivan, James, E-mail: james.sullivan@anu.edu.au [ARC Centre of Excellence for Antimatter-Matter Studies (CAMS), Research School of Physics and Engineering, Australian National University, Canberra (Australia)

    2014-11-14

    The free-volume of a matrix is a fundamental parameter that relates to its molecular and bulk characteristics, such as crystalline change and glass transition behavior. In starch-based bionanocomposite, we investigated the effect of the addition of montmorillonite nanoclay (MMT) and food plasticizers (glycerol and sorbitol) on changes of molecular pore size (including pore volume and pore distribution) using the Positron Annihilation Lifetime Spectroscopy (PALS) method. The results demonstrated counter-intuitive impact of MMT on the total free-volume where the total free-volume increased within the polymeric matrix. When compared to the pure matrix free-volume, the addition of MMT also resulted in the appearance of a broader distribution of the void sizes. The plasticizers, on the other hand, apparently occupied the void spaces, and therefore decreased the free-volume of the matrix. Further, together with the small angle X-ray scattering (SAXS) analysis, we concluded that this is a result of interplay between the plasticizer-plasticizer interactions and the polymer–plasticizer interactions. For example, in the starch/glycerol/MMT system, the pore radii slightly decrease upon the increasing of glycerol amount (OG210 = O.27 nm and OG220 = 0.26 nm), but the relative weight did increase with the increasing glycerol concentration. However, increasing the sorbitol amount increased the pore size from 0.23 nm(OS210) to 0.28 nm(OS220). Furthermore, the addition MMT in the OS010 system, promote the emergence of a new dateable pore radius(0.90 nm), and the total weight significantly increased from 13.70 (OS010) to 19.5% (OS210). We suggest that the pore variation (size and distribution) due to the MMT and plasticizers are reflected in the polymer glass transition and crystallinity because ultimately, the, total free-volume is a reflection of level of interactions existing within the bulk of these nanocomposites. - Highlights: • PALS is applied to explore the

  19. Lifetime improvement and beam stabilization by longitudinal phase modulation at the DELTA electron storage ring; Lebensdauerverbesserung und Strahlstabilisierung durch longitudinale Phasenmodulation am Elektronenspreicherring DELTA

    Energy Technology Data Exchange (ETDEWEB)

    Fuersch, Jonathan

    2014-10-16

    In DELTA especially at high beam currents often the occurence of an instability of a longitudinal oscillation mode is observed. In the framework of the present thesis first with different procedure the cause of the longitudinal oscillation mode, which is especially strongly excited at high beam currents, is searched for. Thereby connections between the occurrence of this mode and parameters from the region of the storage-ring high-frequency system is observed. It is shown by comparison of different procedures, simulation calculations, and experimental pre-examinations, that especially by a phase modulation of the storage-ring high frequency an essential improvement of especially the longitudinal beam stability and the beam lifetime can be reached. For the durable and reliable improvement of these beam properties in the framework of the present thesis a system for the longitudinal phase modulation of the after-acceleration voltage in the cavity resonator of the DELTA storage ring is concipated, developed, constructed, taken in operation, and tested. Finally the results aimed hereby are presented and discussed.

  20. Characterisation of neutral hydrogen beam by means of active balmer-a-spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wachter, C

    1999-01-01

    Neutral particle beams are used in thermal nuclear experiments for plasma heating and current drive, and as a diagnostic tool for active spectroscopy. Within the frame of this thesis eight viewing lines for H{sub {alpha}}-spectroscopy have been installed at the end of the injector to observe the fully established neutral beam. The viewing lines are all parallel to the horizontal plane and include small angles with the beam axis, in order to make use of the Doppler effect which separates the signals from the three energy components from each other and from the H{sub {alpha}}-emission of the thermal particles. A multi-Gaussian fit code has been applied to give the amplitudes, positions and widths of the Gauss shaped signals. From this data, the beam composition and, including the physics processes in the acceleration and neutralisation sections, the ion species fractions in the source have been calculated. Furthermore, the vertical density profile and an estimation of the absolute particle density distribution based on an absolute calibration resulted. From the line positions the exact acceleration voltage has been obtained. The line widths allow an estimate of the horizontal divergence. During this work, two ion sources, the 'Pagoda' and the 'Sourcette', have been investigated to obtain the ion species ratio and beam profile. The comparison of the spectroscopic with the calorimetric results gives a useful insight into the beam steering geometry. (author)

  1. High-resolution electron collision spectroscopy with multicharged ions in merged beams

    Energy Technology Data Exchange (ETDEWEB)

    Lestinsky, M.

    2007-04-18

    The Heidelberg ion storage ring Tsr is currently the only ring equipped with two independent devices for the collinear merging of a cold electron beam with stored ions. This greatly improves the potential of electron-ion collision experiments, as the ion beam can be cooled with one electron beam, while the other one is used as a dedicated target for energy-resolved electron collision processes, such as recombination. The work describes the implementation of this system for rst electron collision spectroscopy experiments. A detection system has been realized including an ion detector and specroscopic beam-control software and instrumentation. Moreover, in order to improve the spectroscopic resolution systematical studies of intrinsic relaxation processes in the electron beam have been carried out. These include the dependence on the electron beam density, the magnetic guiding eld strength, and the acceleration geometry. The recombination measurements on low-lying resonances in lithiumlike Sc{sup 18+} yield a high-precision measurement of the 2s-2p{sub 3/2} transition energy in this system. Operation of the two-electron-beam setup at high collision energy ({approx}1000 eV) is established using resonances of hydrogenlike Mg{sup 11+}, while the unique possibility of modifying the beam-merging geometry con rms its importance for the electron-ion recombination rate at lowest relative energy, as demonstrated on F{sup 6+}. (orig.)

  2. Impact of diagnostic neutral beam optimization on active spectroscopy in MST

    Science.gov (United States)

    Feng, Xiande; Nornberg, Mark. D.; den Hartog, Daniel. J.; Oliva, Steven. P.; Craig, Darren; Univ of Wisconsin, Madison Team; Wheaton College, IL Collaboration

    2016-10-01

    The hydrogen diagnostic neutral beam on MST provides local measurements of impurity ion emission through charge exchange recombination spectroscopy (CHERS) and of core-localized magnetic field through the motional Stark effect (MSE). The beam has been optimized to operate at 50kV, 4A steady beam current with 20ms beam pulse and 75% primary energy ion fraction. It's achieved by tuning the beam voltage, arc current, fuel line pressure, arc and high voltage module timing, and the magnetic isolation field. Electron density measurements in the ion source revealed that ion extraction is maximized under low density conditions which are thought to affect the shape of the ion sheath at the extraction grid. The sheath may be transitioning from a planar or convex shape at high density to one which is concave which helps focus the ion trajectories and produce higher beam current. With the improvements in beam operation, the CHERS signal is expected to increase by 20%-30%, and the Stark broadening is expected to increase by 10%. These signal increases will help resolve convolved fine-structure components in both analyses. Beam voltage ripple is also measured to better quantify the accuracy of spectral MSE and CHERS measurement. This work is supported by the U.S. DOE.

  3. A synthetic diagnostic for beam emission spectroscopy in the helically symmetric experiment stellarator

    Science.gov (United States)

    Dobbins, T. J.; Kumar, S. T. A.; Anderson, D. T.

    2016-11-01

    The Helically Symmetric Experiment (HSX) has a number of active spectroscopy diagnostics. Due to the relatively large beam width compared to the plasma minor radius, it is difficult to achieve good spatial resolution at the core of the HSX plasma. This is due to the fact that the optical sightline cuts through many flux surfaces with varying field vectors within the beam. In order to compare the experimental results with theoretical models it is important to accurately model the beam width effects. A synthetic diagnostic has been developed for this purpose. This synthetic diagnostic calculates the effect of spot size and beam width on the measurements of quantities of interest, including radial electric field, flow velocity, and Stark polarization.

  4. Cascaded two-photon spectroscopy of Yb atoms with a transportable effusive atomic beam apparatus.

    Science.gov (United States)

    Song, Minsoo; Yoon, Tai Hyun

    2013-02-01

    We present a transportable effusive atomic beam apparatus for cascaded two-photon spectroscopy of the dipole-forbidden transition (6s(2)(1)S0↔ 6s7s (1)S0) of Yb atoms. An ohmic-heating effusive oven is designed to have a reservoir volume of 1.6 cm(3) and a high degree of atomic beam collimation angle of 30 mrad. The new atomic beam apparatus allows us to detect the spontaneously cascaded two-photons from the 6s7s(1)S0 state via the intercombination 6s6p(3)P1 state with a high signal-to-noise ratio even at the temperature of 340 °C. This is made possible in our apparatus because of the enhanced atomic beam flux and superior detection solid angle.

  5. Molecular Beam Optical Zeeman Spectroscopy of Vanadium Monoxide, VO

    Science.gov (United States)

    Nguyen, Trung; Zhang, Ruohan; Steimle, Timothy

    2016-06-01

    Like almost all astronomical studies, exoplanet investigations are observational endeavors that rely primarily on remote spectroscopic sensing to infer the physical properties of planets. Most exoplanet related information is inferred from to temporal variation of luminosity of the parent star. An effective method of monitoring this variation is via Magnetic Doppler Imaging (MDI), which uses optical polarimetry of paramagnetic molecules or atoms. One promising paramagnetic stellar absorption is the near infrared spectrum of VO. With this in mind, we have begun a project to record and analyze the field-free and Zeeman spectrum of the band. A cold (approx. 20 K) beam of VO was probed with a single frequency laser and detected using laser induced fluorescence. The determined spectral parameters will be discussed and compared to those extracted from the analysis of a hot spectrum. Supported by the National Science Foundation under the Grant No. CHE-1265885. O. Kochukhov, N. Rusomarov, J. A. Valenti, H. C. Stempels, F. Snik, M. Rodenhuis, N. Piskunov, V. Makaganiuk, C. U. Keller and C. M. Johns-Krull, Astron. Astrophys. 574 (Pt. 2), A79/71-A79/12 (2015). S. V. Berdyugina, Astron. Soc. Pac. Conf. Ser. 437 (Solar Polarization 6), 219-235 (2011). S. V. Berdyugina, P. A. Braun, D. M. Fluri and S. K. Solanki, Astron. Astrophys. 444 (3), 947-960 (2005). A. S. C. Cheung, P. G. Hajigeorgiou, G. Huang, S. Z. Huang and A. J. Merer, J. Mol. Spectrosc. 163 (2), 443-458 (1994)

  6. Beam characterization by means of emission spectroscopy in the ELISE test facility

    Science.gov (United States)

    Barbisan, M.; Bonomo, F.; Fantz, U.; Wünderlich, D.

    2017-05-01

    The ELISE (extraction from a large ion source experiment) test facility at IPP Garching hosts a RF H -/D - ion source and an acceleration system. Its target is to demonstrate the performance foreseen for the ITER neutral beam injector (NBI) system in terms of extracted current density (H/D), fraction of co-extracted electrons and pulse duration. The size of the ELISE extraction area is half that foreseen for the ITER NBI. This paper presents a detailed study of the ELISE beam divergence and uniformity. In particular, it was possible to describe the beam as the sum of two components at very different divergence: about 2° versus 5° ÷ 7°. As test cases, the beam properties have been measured as function of two source parameters. The first one is the current flowing through the grid facing the plasma, the plasma grid (PG), in order to generate the magnetic filter field. The second one is the bias current flowing between the PG and the source walls. Both the filter field and the bias current influence the fraction of co-extracted electrons, but also the properties of the plasma just in front of the extraction system and the beam properties. The divergence and the uniformity of the beam have been measured by a beam emission spectroscopy (BES) diagnostic; the detailed analysis of the raw spectra collected by BES led to describing the beam with two components of different divergence. This concept has been supported by the information given by thermal imaging of the diagnostic calorimeter. Further support to the proposed beam model has been found in the behavior of the currents flowing in the acceleration system and beamline components; these currents are given by the most divergent (charged) particles of the beam.

  7. Combined hydrogen and lithium beam emission spectroscopy observation system for Korea Superconducting Tokamak Advanced Research

    Energy Technology Data Exchange (ETDEWEB)

    Lampert, M. [Wigner RCP, Euratom Association-HAS, Budapest (Hungary); BME NTI, Budapest (Hungary); Anda, G.; Réfy, D.; Zoletnik, S. [Wigner RCP, Euratom Association-HAS, Budapest (Hungary); Czopf, A.; Erdei, G. [Department of Atomic Physics, BME IOP, Budapest (Hungary); Guszejnov, D.; Kovácsik, Á.; Pokol, G. I. [BME NTI, Budapest (Hungary); Nam, Y. U. [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2015-07-15

    A novel beam emission spectroscopy observation system was designed, built, and installed onto the Korea Superconducting Tokamak Advanced Research tokamak. The system is designed in a way to be capable of measuring beam emission either from a heating deuterium or from a diagnostic lithium beam. The two beams have somewhat complementary capabilities: edge density profile and turbulence measurement with the lithium beam and two dimensional turbulence measurement with the heating beam. Two detectors can be used in parallel: a CMOS camera provides overview of the scene and lithium beam light intensity distribution at maximum few hundred Hz frame rate, while a 4 × 16 pixel avalanche photo-diode (APD) camera gives 500 kHz bandwidth data from a 4 cm × 16 cm region. The optics use direct imaging through lenses and mirrors from the observation window to the detectors, thus avoid the use of costly and inflexible fiber guides. Remotely controlled mechanisms allow adjustment of the APD camera’s measurement location on a shot-to-shot basis, while temperature stabilized filter holders provide selection of either the Doppler shifted deuterium alpha or lithium resonance line. The capabilities of the system are illustrated by measurements of basic plasma turbulence properties.

  8. Pre-martensitic phenomena of thermoelastic martensitic transformation of NiTiCu alloys studied with positron annihilation lifetime spectroscopy

    Directory of Open Access Journals (Sweden)

    J. Katsuyama, H. Araki, M. Mizuno and Y. Shirai

    2004-01-01

    Full Text Available Many anomalous phenomena have been observed in NiTi alloys above martensite start temperature, such as softening of the shear constants, increase of internal friction and diffuse scattering of TEM. However, little information has been obtained about the change in the electron system of the parent phase prior to the martensitic transformation, which should be the origin of all pre-martensitic phenomena. In this work, the temperature change of positron annihilation lifetime, which is quite sensitive to electronic-structural changes of matter, were carried out for NiTiCu alloys. The alloys show martensitic transformation from a B2 (cubic phase to a B19' (monoclinic phase via a B19 (orthorhombic phase as the temperature is lowered. We have found anomalous positron lifetime changes in Ni10Ti50Cu40 and Ni15Ti50Cu35 alloys which show a B2–B19–B19' phase transformation. Positron lifetime increases anomalously with decreasing temperature at temperatures higher than the transformation temperature into a B19' phase. On the other hand, positron lifetime does not show any anomaly in the B2 phase of Ni30Ti50Cu20 alloy which shows B2–B19 phase transformation. The positron lifetime of the parent B2 phase shows good agreement with the theoretically-calculated value. Those of the martensite phases of B19 and B19', although, are about 30 ps longer than calculated ones. This big difference between experimental and calculated positron lifetimes cannot be explained by any existing theory.

  9. Practical Entangled-Photon Virtual-State Spectroscopy using Intense Twin Beams

    CERN Document Server

    Svozilík, Jiří; León-Montiel, Roberto de J

    2016-01-01

    We propose a new practical approach towards ultrasensitive measurements in chemical and biological systems based on the so-called virtual-state spectroscopy technique. The proposed scheme makes use of intense twin beams generated by pump pulses with different frequency chirps to successfully extract information about the virtual states that contribute to the two-photon excitation of an absorbing medium. Interestingly, we show that our approach may enable entangled-photon absorption rates up to four orders of magnitude larger than previously reported. Because of its simplicity, our method paves the way towards the first experimental implementation of the virtual-state spectroscopy technique.

  10. Ion spectroscopy for improvement of the physical beam model for therapy planning in ion beam therapy

    Energy Technology Data Exchange (ETDEWEB)

    Arico, Giulia

    2016-11-23

    Helium and carbon ions enable a more conformal dose distribution, narrower penumbra and higher relative biological effectiveness than photon and proton radiotherapy. However, they may undergo nuclear fragmentation in the patient tissues and the arising secondary fragments affect the delivered biological dose distributions. Currently there is a lack of data regarding ion nuclear fragmentation. One reason is the large size (up to some meters) of the experimental setups required for the investigations. In this thesis a new method is presented, which makes use of versatile pixelated semiconductor detectors (Timepix). This method is based on tracking of single particles and pattern recognition of their signals in the detectors. Measurements were performed at the HIT facility. The mixed radiation field arising from 430 MeV/u carbon ion beams and 221 MeV/u helium ion beams in water and in PMMA targets was investigated. The amounts of primary (carbon or helium) ions detected behind targets with the same water equivalent thickness (WET) were found to be in agreement within the statistical uncertainties. However, more fragments (differences up to 20% in case of H) and narrower lateral particle distributions were measured behind the PMMA than the water targets. The spectra of ions behind tissue surrogates and corresponding water targets with the same WET were analysed. The results obtained with adipose and inner bone surrogates and with the equivalent water phantoms were found to be consistent within the uncertainties. Significant differences in the results were observed in the case of lung and cortical bone surrogates when compared to the water phantoms. The experimental results were compared to FLUKA Monte Carlo simulations. This comparison could contribute to enhance the ion interaction models currently implemented for {sup 12}C and {sup 4}He ion beams.

  11. Practical Entangled-Photon Virtual-State Spectroscopy using Intense Twin Beams

    OpenAIRE

    2016-01-01

    We propose a new practical approach towards ultrasensitive measurements in chemical and biological systems based on the so-called virtual-state spectroscopy technique. The proposed scheme makes use of intense twin beams generated by pump pulses with different frequency chirps to successfully extract information about the virtual states that contribute to the two-photon excitation of an absorbing medium. Interestingly, we show that our approach may enable entangled-photon absorption rates up t...

  12. Ultra-sensitive in-beam gamma-ray spectroscopy for nuclear astrophysics at LUNA

    CERN Document Server

    Caciolli, A; Bemmerer, D; Bonetti, R; Broggini, C; Confortola, F; Corvisiero, P; Costantini, H; Elekes, Z; Formicola, A; Fülöp, Z; Gervino, G; Guglielmetti, A; Gustavino, C; Gyurky, Gy; Imbriani, G; Junker, M; Laubenstein, M; Lemut, A; Limata, B; Marta, M; Mazzocchi, C; Menegazzo, R; Prati, P; Roca, V; Rolfs, C; Alvarez, C Rossi; Somorjai, E; Straniero, O; Strieder, F; Terrasi, F; Trautvetter, H P

    2008-01-01

    Ultra-sensitive in-beam gamma-ray spectroscopy studies for nuclear astrophysics are performed at the LUNA (Laboratory for Underground Nuclear Astrophysics) 400 kV accelerator, deep underground in Italy's Gran Sasso laboratory. By virtue of a specially constructed passive shield, the laboratory gamma-ray background for E_\\gamma < 3 MeV at LUNA has been reduced to levels comparable to those experienced in dedicated offline underground gamma-counting setups. The gamma-ray background induced by an incident alpha-beam has been studied. The data are used to evaluate the feasibility of sensitive in-beam experiments at LUNA and, by extension, at similar proposed facilities.

  13. High resolution EUV spectroscopy of xenon ions with a compact electron beam ion trap

    Science.gov (United States)

    Ali, Safdar; Nakamura, Nobuyuki

    2017-09-01

    We performed high resolution extreme ultraviolet (EUV) spectroscopy measurements of highly charged xenon ions with a compact electron beam ion trap. The spectra were recorded with a flat-field grazing incidence spectrometer while varying the electron beam energy between 200 and 890 eV. We measured the wavelengths for several lines of Rh-like Xe9+ - Cd-like Xe6+ and Cu-like Xe25+- Se-like Xe20+ in the range of 150-200 Å with an uncertainty of 0.05 Å. Previously, most of these lines have been reported from EBITs with a wavelength uncertainty of 0.2 Å. Additionally, based on the electron beam energy dependence of the observed spectra we tentatively identified three new lines, which were reported as unidentified lines in the previous studies.

  14. Quantitative Assessment of Amino Acid Damage upon keV Ion Beam Irradiation Through FTIR Spectroscopy

    Science.gov (United States)

    Huang, Qing; Ke, Zhigang; Su, Xi; Yuan, Hang; Zhang, Shuqing; Yu, Zengliang

    2010-06-01

    Ion beam irradiation induces important biological effects and it is a long-standing task to acquire both qualitative and quantitative assessment of these effects. One effective way in the investigation is to utilize Fourier transformation infrared (FTIR) spectroscopy because it can offer sensitive and non-invasive measurements. In this paper a novel protocol was employed to prepare biomolecular samples in the form of thin and transversely uniform solid films that were suitable for both infrared and low-energy ion beam irradiation experiments. Under the irradiation of N+ and Ar+ ion beams of 25 keV with fluence ranging from 5×1015 ions/cm2 to 2.5×10 ions/cm2, the ion radio-sensitivity of four amino acids, namely, glycine, tyrosine, methionine and phenylalanine, were evaluated and compared. The ion beam irradiation caused biomolecular decomposition accompanied by molecular desorption of volatile species and the damage was dependent on ion type, fluence, energy and types of amino acids. The effectiveness of application of FTIR spectroscopy to the quantitative assessment of biomolecular damage dose effect induced by low-energy ion radiation was thus demonstrated.

  15. Application of positron annihilation lifetime spectroscopy (PALS) to study the nanostructure in amphiphile self-assembly materials: phytantriol cubosomes and hexosomes.

    Science.gov (United States)

    Dong, Aurelia W; Fong, Celesta; Waddington, Lynne J; Hill, Anita J; Boyd, Ben J; Drummond, Calum J

    2015-01-21

    Self-assembled amphiphile nanostructures of colloidal dimensions such as cubosomes and hexosomes are of interest as delivery vectors in pharmaceutical and nanomedicine applications. Translation would be assisted through a better of understanding of the effects of drug loading on the internal nanostructure, and the relationship between this nanostructure and drug release profile. Positron annihilation lifetime spectroscopy (PALS) is sensitive to local microviscosity and is used as an in situ molecular probe to examine the Q2 (cubosome) → H2 (hexosome) → L2 phase transitions of the pharmaceutically relevant phytantriol-water system in the presence of a model hydrophobic drug, vitamin E acetate (VitEA). It is shown that the ortho-positronium lifetime (τ) is sensitive to molecular packing and mobility and this has been correlated with the rheological properties of individual lyotropic liquid crystalline mesophases. Characteristic PALS lifetimes for L2 (τ4∼ 4 ns) ∼ H2 (τ4∼ 4 ns) > Q(2 Pn3m) (τ4∼ 2.2 ns) are observed for the phytantriol-water system, with the addition of VitEA yielding a gradual increase in τ from τ∼ 2.2 ns for cubosomes to τ∼ 3.5 ns for hexosomes. The dynamic chain packing at higher temperatures and in the L2 and H2 phases is qualitatively less "viscous", consistent with rheological measurements. This information offers increased understanding of the relationship between internal nanostructure and species permeability.

  16. Probing electronic lifetimes and phonon anharmonicities in high-quality chemical vapor deposited graphene by magneto-Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, Christoph, E-mail: cneumann@physik.rwth-aachen.de; Stampfer, Christoph [JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, 52074 Aachen (Germany); Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich (Germany); Halpaap, Donatus; Banszerus, Luca; Schmitz, Michael; Beschoten, Bernd [JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, 52074 Aachen (Germany); Reichardt, Sven [JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, 52074 Aachen (Germany); Physics and Materials Science Research Unit, Université du Luxembourg, 1511 Luxembourg (Luxembourg); Watanabe, Kenji; Taniguchi, Takashi [National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan)

    2015-12-07

    We present a magneto-Raman study on high-quality single-layer graphene grown by chemical vapor deposition (CVD) that is fully encapsulated in hexagonal boron nitride by a dry transfer technique. By analyzing the Raman D, G, and 2D peaks, we find that the structural quality of the samples is comparable with state-of-the-art exfoliated graphene flakes. From B-field dependent Raman measurements, we extract the broadening and associated lifetime of the G peak due to anharmonic effects. Furthermore, we determine the decay width and lifetime of Landau level (LL) transitions from magneto-phonon resonances as a function of laser power. At low laser power, we find a minimal decay width of 140 cm{sup −1} highlighting the high electronic quality of the CVD-grown graphene. At higher laser power, we observe an increase of the LL decay width leading to a saturation, with the corresponding lifetime saturating at a minimal value of 18 fs.

  17. Where Do Photogenerated Holes Go in Anatase:Rutile TiO2? A Transient Absorption Spectroscopy Study of Charge Transfer and Lifetime.

    Science.gov (United States)

    Kafizas, Andreas; Wang, Xiuli; Pendlebury, Stephanie R; Barnes, Piers; Ling, Min; Sotelo-Vazquez, Carlos; Quesada-Cabrera, Raul; Li, Can; Parkin, Ivan P; Durrant, James R

    2016-02-11

    Anatase:rutile TiO2 junctions are often shown to be more photocatalytically active than anatase or rutile alone, but the underlying cause of this improvement is not fully understood. Herein, we employ transient absorption spectroscopy to study hole transfer across the anatase:rutile heterojunction in films as a function of phase composition. By exploiting the different signatures in the photoinduced absorption of trapped charges in anatase and rutile, we were able to separately track the yield and lifetime of holes in anatase and rutile sites within phase composites. Photogenerated holes transfer from rutile to anatase on submicrosecond time scales. This hole transfer can significantly increase the anatase hole yield, with a 20:80 anatase:rutile composite showing a 5-fold increase in anatase holes observed from the microsecond. Hole transfer does not result in an increase in charge-carrier lifetime, where an intermediate recombination dynamic between that of pure anatase (t1/2 ≈ 0.5 ms) and rutile (t1/2 ≈ 20 ms) is found in the anatase:rutile junction (t1/2 ≈ 4 ms). Irrespective of what the formal band energy alignment may be, we demonstrate the importance of trap-state energetics for determining the direction of photogenerated charge separation across heterojunctions and how transient absorption spectroscopy, a method that can specifically track the migration of trapped charges, is a useful tool for understanding this behavior.

  18. Laser induced breakdown spectroscopy based on single beam splitting and geometric configuration for effective signal enhancement.

    Science.gov (United States)

    Yang, Guang; Lin, Qingyu; Ding, Yu; Tian, Di; Duan, Yixiang

    2015-01-05

    A new laser induced breakdown spectroscopy (LIBS) based on single-beam-splitting (SBS) and proper optical geometric configuration has been initially explored in this work for effective signal enhancement. In order to improve the interaction efficiency of laser energy with the ablated material, a laser beam operated in pulse mode was divided into two streams to ablate/excite the target sample in different directions instead of the conventional one beam excitation in single pulse LIBS (SP-LIBS). In spatial configuration, the laser beam geometry plays an important role in the emission signal enhancement. Thus, an adjustable geometric configuration with variable incident angle between the two splitted laser beams was constructed for achieving maximum signal enhancement. With the optimized angles of 60° and 70° for Al and Cu atomic emission lines at 396.15 nm and 324.75 nm respectively, about 5.6- and 4.8-folds signal enhancements were achieved for aluminum alloy and copper alloy samples compared to SP-LIBS. Furthermore, the temporal analysis, in which the intensity of atomic lines in SP-LIBS decayed at least ten times faster than the SBS-LIBS, proved that the energy coupling efficiency of SBS-LIBS was significantly higher than that of SP-LIBS.

  19. Laser Induced Breakdown Spectroscopy Based on Single Beam Splitting and Geometric Configuration for Effective Signal Enhancement

    Science.gov (United States)

    Yang, Guang; Lin, Qingyu; Ding, Yu; Tian, Di; Duan, Yixiang

    2015-01-01

    A new laser induced breakdown spectroscopy (LIBS) based on single-beam-splitting (SBS) and proper optical geometric configuration has been initially explored in this work for effective signal enhancement. In order to improve the interaction efficiency of laser energy with the ablated material, a laser beam operated in pulse mode was divided into two streams to ablate/excite the target sample in different directions instead of the conventional one beam excitation in single pulse LIBS (SP-LIBS). In spatial configuration, the laser beam geometry plays an important role in the emission signal enhancement. Thus, an adjustable geometric configuration with variable incident angle between the two splitted laser beams was constructed for achieving maximum signal enhancement. With the optimized angles of 60° and 70° for Al and Cu atomic emission lines at 396.15 nm and 324.75 nm respectively, about 5.6- and 4.8-folds signal enhancements were achieved for aluminum alloy and copper alloy samples compared to SP-LIBS. Furthermore, the temporal analysis, in which the intensity of atomic lines in SP-LIBS decayed at least ten times faster than the SBS-LIBS, proved that the energy coupling efficiency of SBS-LIBS was significantly higher than that of SP-LIBS. PMID:25557721

  20. Measurements of the $\\Xi^0$ Lifetime and the $\\overline{\\Xi^0}/\\Xi^0$ Flux Ratio in a Neutral Beam

    CERN Document Server

    Batley, J Richard; Lazzeroni, C; Munday, D J; Patel, M; Slater, M W; Wotton, S A; Arcidiacono, R; Bocquet, G; Ceccucci, A; Cundy, Donald C; Doble, N; Falaleev, V; Gatignon, L; Gonidec, A; Grafström, P; Kubischta, Werner; Mikulec, I; Norton, A; Panzer-Steindel, B; Rubin, P; Wahl, H; Goudzovski, E; Khristov, P Z; Kekelidze, V D; Litov, L; Madigozhin, D T; Molokanova, N A; Potrebenikov, Yu K; Stoynev, S; Zinchenko, A I; Monnier, E; Swallow, E; Winston, R; Sacco, R; Walker, A; Baldini, W; Dalpiaz, P; Frabetti, P L; Gianoli, A; Martini, M; Petrucci, F; Savrié, M; Scarpa, M; Bizzeti, A; Calvetti, M; Collazuol, G; Iacopini, E; Lenti, M; Ruggiero, G; Veltri, M; Behler, M; Eppard, K; Eppard, M; Hirstius, A; Kleinknecht, K; Koch, U; Marouelli, P; Masetti, L; Moosbrugger, U; Morales-Morales, C; Peters, A; Wanke, R; Winhart, A; Dabrowski, A; Fonseca-Martin, T; Velasco, M; Anzivino, Giuseppina; Cenci, P; Imbergamo, E; Lamanna, G; Lubrano, P; Michetti, A; Nappi, A; Pepé, M; Petrucci, M C; Piccini, M; Valdata, M; Cerri, C; Costantini, F; Fantechi, R; Fiorini, L; Giudici, S; Mannelli, I; Pierazzini, G M; Sozzi, M; Cheshkov, C; Chèze, J B; De Beer, M; Debu, P; Gouge, G; Marel, Gérard; Mazzucato, E; Peyaud, B; Vallage, B; Holder, M; Maier, A; Ziolkowski, M; Biino, C; Cartiglia, N; Clemencic, M; Goy-Lopez, S; Marchetto, F; Menichetti, E; Pastrone, N; Wislicki, W; Dibon, Heinz; Jeitler, Manfred; Markytan, Manfred; Neuhofer, G; Widhalm, L

    2007-01-01

    A total of 235 698 Xi0 -> Lambda pi0 and 21 527 anti-Xi0 -> anti-Lambda pi0 decays were selected from data obtained by the NA48/1 experiment at CERN. From this sample, the lifetime of the Xi0 hyperon was measured to be (3.065 +- 0.012(stat) +- 0.014(syst)) x 10^-10 s. This result is about two standard deviations above the world average and an order of magnitude more precise than the previous best measurement. With the same data sample, we have measured the ratio of anti-Xi0 and Xi0 fluxes in proton collisions at 400 GeV/c on a beryllium target.

  1. Electron beam exposure mechanisms in hydrogen silsesquioxane investigated by vibrational spectroscopy and in-situ electron beam induced desorption

    Energy Technology Data Exchange (ETDEWEB)

    Olynick, D.L.; Cord, B.; Schipotinin, A.; Ogletree, D.F.; Schuck, P.J.

    2009-11-13

    Hydrogen Silsesquioxane (HSQ) is used as a high-resolution resist with resolution down below 10nm half-pitch. This material or materials with related functionalities could have widespread impact in nanolithography and nanoscience applications if the exposure mechanism was understood and instabilities controlled. Here we have directly investigated the exposure mechanism using vibrational spectroscopy (both Raman and Fourier transform Infrared) and electron beam desorption spectrocscopy (EBDS). In the non-networked HSQ system, silicon atoms sit at the corners of a cubic structure. Each silicon is bonded to a hydrogen atom and bridges 3 oxygen atoms (formula: HSiO3/2). For the first time, we have shown, via changes in the Si-H2 peak at ~;;2200 cm -1 in the Raman spectra and the release of SiHx products in EBID, that electron-bam exposed materials crosslinks via a redistribution reaction. In addition, we observe the release of significantly more H2 than SiH2 during EBID, which is indicative of additional reaction mechanisms. Additionally, we compare the behavior of HSQ in response to both thermal and electron-beam induced reactions.

  2. MINOS: A vertex tracker coupled to a thick liquid-hydrogen target for in-beam spectroscopy of exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Obertelli, A.; Delbart, A.; Anvar, S.; Audirac, L.; Authelet, G.; Bruyneel, B.; Calvet, D.; Chateau, F.; Corsi, A.; Gheller, J.M.; Giganon, A.; Lahonde-Hamdoun, C.; Leboeuf, D.; Loiseau, D.; Mohamed, A.; Mols, J.P.; Peron, C.; Peyaud, A.; Pollacco, E.C.; Prono, G.; Rousse, J.Y.; Santamaria, C. [CEA, Centre de Saclay, IRFU, Gif-sur-Yvette (France); Baba, H.; Doornenbal, P.; Otsu, H.; Uesaka, T. [RIKEN Nishina Center, Wako, Saitama (Japan)

    2014-01-15

    MINOS is a new apparatus dedicated to in-beam nuclear structure experiments with low-intensity exotic beams in inverse kinematics at intermediate energies above 150 MeV/nucleon. The device is composed of a thick liquid-hydrogen target coupled to a compact time projection chamber (TPC) serving as a vertex tracker. Either used for in-beam gamma spectroscopy of bound excited states or invariant-mass spectroscopy of unbound states, MINOS aims at improving the luminosity by a very significant factor compared to standard solid-target material experiments while improving experimental resolutions. (orig.)

  3. Proceeding of the workshop on gamma-ray spectroscopy utilizing heavy-ion, photon and RI beams

    Energy Technology Data Exchange (ETDEWEB)

    Oshima, Masumi; Sugita, Michiaki; Hayakawa, Takehito [eds.

    1998-03-01

    Three time since 1992, we have held the symposia entitled `Joint Spectroscopy Experiments Utilizing JAERI Tandem-Booster Accelerator` at the Tokai Research Establishment. In the symposia, we have mainly discussed the plans of experiments to be done in this joint program. The joint program started in 1994. Several experiments have been made since and some new results have already come up. This symposium `Gamma-ray Spectroscopy utilizing heavy-ion, Photon and RI beams` was held at Tokai Research Establishment of JAERI. Because this symposium is the first occasion after the program started, the first purpose of the symposium is to present and discuss the experimental results so far obtained using the JAERI Tandem-Booster. The second purpose of the symposium is to discuss new possibilities of gamma-ray spectroscopy using new resources such as RI-beam and Photon-beam. The participants from RIKEN, Tohoku University and JAERI Neutron Science Research Center presented the future plans of experiments with RI-beam at each facility. Compared with these nuclear beams, photon beam provides a completely new tool for the {gamma}-ray spectroscopy, which is achieved by inverse Compton scattering between high-energy electron and laser beams. The 23 of the presented papers are indexed individually. (J.P.N.)

  4. Synthetic diagnostic for the beam emission spectroscopy diagnostic using a full optical integration

    Science.gov (United States)

    Hausammann, L.; Churchill, R. M.; Shi, L.

    2017-02-01

    The beam emission spectroscopy (BES) diagnostic is used to measure fluctuations of electron density in the edge and core of fusion plasmas, and is a key in understanding turbulence in a plasma reactor. A synthetic BES diagnostic for the turbulence simulation code XGC1 has been developed using a realistic neutral beam model and an optical system easily adaptable to different kinds of tokamaks. The beam is modeled using multiple beam energy components, each one with a fraction of the total energy and their own mass and energy (mono-energetic components). The optical system consists of a lens focusing a bundle of optical fibers and resulting in a 2D measurement. The synthetic diagnostic gives similar correlation functions and behaviour of the turbulences than the usual methods that do not take into account the full 3D optical effects. The results, based on a simulation of XGC1, contain an analysis of the correlation (in space and time), a comparison of different approximations possible and their importance in accurately modeling the BES diagnostic.

  5. In-beam γ-ray Spectroscopy of Level Structure in 134Ba

    Institute of Scientific and Technical Information of China (English)

    LuoPeng; LiuMinliang; LiuZhong; ZhangYuhu; ZhouXiaohong; GuoYingxiang; MaYingjun; Y.Sasaki; K.Yamada; H.Ohshima; S.Yokose; M.Ishizuka; T.Komatsubara; K.Furuno

    2003-01-01

    Excited states of 134Ba, populated via the heavy-ion induced 128Te(10B, 1p3n)134Ba reaction at 46 MeV beam energy, have been studied to medium and high spins by in-beam γ-ray spectroscopy techniques. The experiment was performed at the tandem accelerator laboratory in the University of Tsukuba, Japan. The target is an isotopically enriched 128Te metallic foil of 2.3mg/cm2 thickness with a 3mg/cm2 gold backing. Nine anti-Compton HPGe detectors were employed for the measurements of γ-γ-t coincidences. The level scheme of 134Ba, deduced from this study, was shown in Fig.1.

  6. Simulating systematic errors in X-ray absorption spectroscopy experiments: Sample and beam effects

    Energy Technology Data Exchange (ETDEWEB)

    Curis, Emmanuel [Laboratoire de Biomathematiques, Faculte de Pharmacie, Universite Rene, Descartes (Paris V)-4, Avenue de l' Observatoire, 75006 Paris (France)]. E-mail: emmanuel.curis@univ-paris5.fr; Osan, Janos [KFKI Atomic Energy Research Institute (AEKI)-P.O. Box 49, H-1525 Budapest (Hungary); Falkenberg, Gerald [Hamburger Synchrotronstrahlungslabor (HASYLAB), Deutsches Elektronen-Synchrotron (DESY)-Notkestrasse 85, 22607 Hamburg (Germany); Benazeth, Simone [Laboratoire de Biomathematiques, Faculte de Pharmacie, Universite Rene, Descartes (Paris V)-4, Avenue de l' Observatoire, 75006 Paris (France); Laboratoire d' Utilisation du Rayonnement Electromagnetique (LURE)-Ba-hat timent 209D, Campus d' Orsay, 91406 Orsay (France); Toeroek, Szabina [KFKI Atomic Energy Research Institute (AEKI)-P.O. Box 49, H-1525 Budapest (Hungary)

    2005-07-15

    The article presents an analytical model to simulate experimental imperfections in the realization of an X-ray absorption spectroscopy experiment, performed in transmission or fluorescence mode. Distinction is made between sources of systematic errors on a time-scale basis, to select the more appropriate model for their handling. For short time-scale, statistical models are the most suited. For large time-scale, the model is developed for sample and beam imperfections: mainly sample inhomogeneity, sample self-absorption, beam achromaticity. The ability of this model to reproduce the effects of these imperfections is exemplified, and the model is validated on real samples. Various potential application fields of the model are then presented.

  7. Annealing Behaviour of Helium Bubbles in Titanium Films by Thermal Desorption Spectroscopy and Positron Beam Analysis

    Institute of Scientific and Technical Information of China (English)

    LIU Chao-Zhuo; ZHOU Zhu-Ying; SHI Li-Qun; WANG Bao-Yi; HAO Xiao-Peng; ZHAO Guo-Qing

    2007-01-01

    @@ Helium-containing Ti films are prepared using magnetron sputtering in the helium-argon atmosphere. Isochronal annealing at different temperatures for an hour is employed to reveal the behaviour of helium bubble growth. Ion beam analysis is used to measure the retained helium content. Helium can release largely when annealing above 970 K. A thermal helium desorption spectroscopy system is constructed for assessment of the evolution of helium bubbles in the annealed samples by linear heating (0.4K/s) from room temperature to 1500K. Also, Doppler broadening measurements of positron annihilation radiation spectrum are performed by using changeable energy positron beam. Bubble coarsening evolves gradually below 680K, migration and coalescence of small bubbles dominates in the range of 680-970K, and the Ostwald ripening mechanism enlarges the bubbles with a massive release above 970K.

  8. Comb-assisted cavity ring-down spectroscopy of a buffer-gas-cooled molecular beam.

    Science.gov (United States)

    Santamaria, Luigi; Sarno, Valentina Di; Natale, Paolo De; Rosa, Maurizio De; Inguscio, Massimo; Mosca, Simona; Ricciardi, Iolanda; Calonico, Davide; Levi, Filippo; Maddaloni, Pasquale

    2016-06-22

    We demonstrate continuous-wave cavity ring-down spectroscopy of a partially hydrodynamic molecular beam emerging from a buffer-gas-cooling source. Specifically, the (ν1 + ν3) vibrational overtone band of acetylene (C2H2) around 1.5 μm is accessed using a narrow-linewidth diode laser stabilized against a GPS-disciplined rubidium clock via an optical frequency comb synthesizer. As an example, the absolute frequency of the R(1) component is measured with a fractional accuracy of ∼1 × 10(-9). Our approach represents the first step towards the extension of more sophisticated cavity-enhanced interrogation schemes, including saturated absorption cavity ring-down or two-photon excitation, to buffer-gas-cooled molecular beams.

  9. In situ photoelectron spectroscopy of molecular-beam-epitaxy grown surfaces

    CERN Document Server

    Oshima, M; Okabayashi, J; Ono, K

    2003-01-01

    Two in situ high-resolution synchrotron radiation photoelectron spectroscopy (SRPES) systems combined with a molecular beam epitaxy (MBE) chamber for III-V compound semiconductors and a laser MBE chamber for strongly correlated oxide films, respectively, have been designed and fabricated to analyze intrinsic and surface/interface electronic structures of these unique materials. The importance of the in situ SRPES has been demonstrated by the results of 1) Si surface nanostructures, 2) GaAs surfaces/interfaces and nanostructures, 3) MnAs magnetic nanostructures, and 4) strongly-correlated La sub 1 sub - sub x Sr sub x MnO sub 3 surfaces/interfaces and superstructures.

  10. In-beam measurement of the hydrogen hypernine splitting - towards antihydrogen spectroscopy

    CERN Document Server

    Diermaier, M.; Kolbinger, B.; Malbrunot, C.; Massiczek, O.; Sauerzopf, C.; Simon, M.C.; Zmeskal, J.; Widmann, E.

    2016-01-01

    Antihydrogen, the lightest atom consisting purely of antimatter, is an ideal laboratory to study the CPT symmetry by comparison to hydrogen. With respect to absolute precision, transitions within the ground-state hyperfine structure (GS-HFS) are most appealing by virtue of their small energy separation. ASACUSA proposed employing a beam of cold antihydrogen atoms in a Rabi-type experiment to determine the GS-HFS in a field-free region. Here we present a measurement of the zero-field hydrogen GS-HFS using the spectroscopy apparatus of ASACUSA's antihydrogen experiment. The measured value of $\

  11. $\\beta$-delayed fission, laser spectroscopy and shape-coexistence studies with radioactive At beams

    CERN Multimedia

    We propose to study the $\\beta$-delayed fission, laser spectroscopy and radioactive decay of the newly available pure beams of neutron-deficient and neutron-rich astatine (Z=85) isotopes. The fission probability and the fission fragment distribution of the even-even isotopes $^{194,196}$Po following the $\\beta$-decay of the isotopes $^{194,196}$At will be studied with the Windmill setup. In-source laser spectroscopy will be performed on the entire astatine isotopic chain, using a combination of the Windmill setup, ISOLTRAP MR-ToF and ISOLDE Faraday. Radioactive decay data will be acquired at the Windmill setup throughout those studies and contribute to the global understanding of the phenomenon of shape coexistence in the neutron-deficient lead region.

  12. An effective method for trapping ion beams in superfluid helium for laser spectroscopy experiments

    Directory of Open Access Journals (Sweden)

    Yang X.F

    2014-03-01

    Full Text Available A novel laser spectroscopy technique -“OROCHI” (Optical Radioisotopes Observation in Condensed Helium as Ion-catcher has been proposed. This method aimed to investigate the structure of exotic nuclei systematically by measuring nuclear spins and moments. For in-situ laser spectroscopy of atoms in He II, a method to trap atoms precisely at the observation region of laser is highly needed. In this work, a setup composed of a degrader, two plastic scintillators and a photon detection system is further tested and verified for adjusting and checking the stopping position of 84–87Rb beam. Details of the current setup, experimental results using this method are presented.

  13. Real-time reflectance-difference spectroscopy of GaAs molecular beam epitaxy homoepitaxial growth

    Directory of Open Access Journals (Sweden)

    A. Lastras-Martínez

    2014-03-01

    Full Text Available We report on real time-resolved Reflectance-difference (RD spectroscopy of GaAs(001 grown by molecular beam epitaxy, with a time-resolution of 500 ms per spectrum within the 2.3–4.0 eV photon energy range. Through the analysis of transient RD spectra we demonstrated that RD line shapes are comprised of two components with different physical origins and determined their evolution during growth. Such components were ascribed to the subsurface strain induced by surface reconstruction and to surface stoichiometry. Results reported in this paper render RD spectroscopy as a powerful tool for the study of fundamental processes during the epitaxial growth of zincblende semiconductors.

  14. Detection of atomic scale changes in the free volume void size of three-dimensional colorectal cancer cell culture using positron annihilation lifetime spectroscopy.

    Science.gov (United States)

    Axpe, Eneko; Lopez-Euba, Tamara; Castellanos-Rubio, Ainara; Merida, David; Garcia, Jose Angel; Plaza-Izurieta, Leticia; Fernandez-Jimenez, Nora; Plazaola, Fernando; Bilbao, Jose Ramon

    2014-01-01

    Positron annihilation lifetime spectroscopy (PALS) provides a direct measurement of the free volume void sizes in polymers and biological systems. This free volume is critical in explaining and understanding physical and mechanical properties of polymers. Moreover, PALS has been recently proposed as a potential tool in detecting cancer at early stages, probing the differences in the subnanometer scale free volume voids between cancerous/healthy skin samples of the same patient. Despite several investigations on free volume in complex cancerous tissues, no positron annihilation studies of living cancer cell cultures have been reported. We demonstrate that PALS can be applied to the study in human living 3D cell cultures. The technique is also capable to detect atomic scale changes in the size of the free volume voids due to the biological responses to TGF-β. PALS may be developed to characterize the effect of different culture conditions in the free volume voids of cells grown in vitro.

  15. Lifetime of anode polymer in magnetically insulated ion diodes for high-intensity pulsed ion beam generation.

    Science.gov (United States)

    Zhu, X P; Dong, Z H; Han, X G; Xin, J P; Lei, M K

    2007-02-01

    Generation of high-intensity pulsed ion beam (HIPIB) has been studied experimentally using polyethylene as the anode polymer in magnetically insulated ion diodes (MIDs) with an external magnetic field. The HIPIB is extracted from the anode plasma produced during the surface discharging process on polyethylene under the electrical and magnetic fields in MIDs, i.e., high-voltage surface breakdown (flashover) with bombardments by electrons. The surface morphology and the microstructure of the anode polymer are characterized using scanning electron microscopy and differential scanning calorimetry, respectively. The surface roughening of the anode polymer results from the explosive release of trapped gases or newly formed gases under the high-voltage discharging, leaving fractured surfaces with bubble formation. The polyethylene in the surface layer degrades into low-molecular-weight polymers such as polyethylene wax and paraffin under the discharging process. Both the surface roughness and the fraction of low molecular polymers apparently increase as the discharging times are prolonged for multipulse HIPIB generation. The changes in the surface morphology and the composition of anode polymer lead to a noticeable decrease in the output of ion beam intensity, i.e., ion current density and diode voltage, accompanied with an increase in instability of the parameters with the prolonged discharge times. The diode voltage (or surface breakdown voltage of polymer) mainly depends on the surface morphology (or roughness) of anode polymers, and the ion current density on the composition of anode polymers, which account for the two stages of anode polymer degradation observed experimentally, i.e., stage I which has a steady decrease of the two parameters and stage II which shows a slow decrease, but with an enhanced fluctuation of the two parameters with increasing pulses of HIPIB generation.

  16. Recombination activity of light-activated copper defects in p-type silicon studied by injection- and temperature-dependent lifetime spectroscopy

    Science.gov (United States)

    Inglese, Alessandro; Lindroos, Jeanette; Vahlman, Henri; Savin, Hele

    2016-09-01

    The presence of copper contamination is known to cause strong light-induced degradation (Cu-LID) in silicon. In this paper, we parametrize the recombination activity of light-activated copper defects in terms of Shockley—Read—Hall recombination statistics through injection- and temperature dependent lifetime spectroscopy (TDLS) performed on deliberately contaminated float zone silicon wafers. We obtain an accurate fit of the experimental data via two non-interacting energy levels, i.e., a deep recombination center featuring an energy level at Ec-Et=0.48 -0.62 eV with a moderate donor-like capture asymmetry ( k =1.7 -2.6 ) and an additional shallow energy state located at Ec-Et=0.1 -0.2 eV , which mostly affects the carrier lifetime only at high-injection conditions. Besides confirming these defect parameters, TDLS measurements also indicate a power-law temperature dependence of the capture cross sections associated with the deep energy state. Eventually, we compare these results with the available literature data, and we find that the formation of copper precipitates is the probable root cause behind Cu-LID.

  17. Control of stopping position of radioactive ion beam in superfluid helium for laser spectroscopy experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yang, X.F., E-mail: yangxf@ribf.riken.jp [School of Physics, Peking University, Chengfu Road, Haidian District, Beijing 100871 (China); RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Furukawa, T. [Dept. of Physics, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397 (Japan); Wakui, T. [Cyclotron and Radioisotope Center Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578 (Japan); Imamura, K. [Dept. of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Tetsuka, H. [Dept. of Physics, Tokyo Gakugei University, 4-1-1 Nukuikitamachi, Koganei, Tokyo 184-8501 (Japan); Fujita, T. [Dept. of Physics, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Yamaguchi, Y. [Dept. of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Tsutsui, Y. [Dept. of Physics, Tokyo Gakugei University, 4-1-1 Nukuikitamachi, Koganei, Tokyo 184-8501 (Japan); Mitsuya, Y. [Dept. of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Ichikawa, Y. [Dept. of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo152-8551 (Japan); Ishibashi, Y. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Dept. of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Yoshida, N.; Shirai, H. [Dept. of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo152-8551 (Japan); Ebara, Y.; Hayasaka, M. [Dept. of Physics, Tokyo Gakugei University, 4-1-1 Nukuikitamachi, Koganei, Tokyo 184-8501 (Japan); Arai, S.; Muramoto, S. [Dept. of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Hatakeyama, A. [Dept. of Applied Physics, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan); Wada, M.; Sonoda, T. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); and others

    2013-12-15

    In order to investigate the structure of exotic nuclei with extremely low yields by measuring nuclear spins and moments, a new laser spectroscopy technique – “OROCHI” (Optical Radioisotopes Observation in Condensed Helium as Ion-catcher) has been proposed in recent years. The feasibility of this technique has been demonstrated by means of a considerable amount of offline and online studies of various atoms in superfluid helium. For in-situ laser spectroscopy of atoms in He II, trapping atoms in the observation region of laser is a key step. Therefore, a method which enables us to trap accelerated atoms at a precise position in He II is highly needed for performing experiment. In this work, a technique making use of a degrader, two plastic scintillators and a photon detection system is established for checking the stopping position of beam based on the LISE++ calculation. The method has been tested and verified by on-line experiments with the {sup 84,85,87}Rb beam. Details of the experimental setup, working procedure and testing results of this method are presented.

  18. In-beam measurement of the hydrogen hypernine splitting - towards antihydrogen spectroscopy

    CERN Document Server

    Diermaier, Martin; The Asacusa AD-3 collaboration; Kolbinger, Bernadette; Malbrunot, Chloé; Massiczek, Oswald; Sauerzopf, Clemens; Simon, Martin Christian; Zmeskal, Johann; Widmann, Eberhard

    2016-01-01

    Antihydrogen, the lightest atom consisting purely of antimatter, is an ideal laboratory to study the CPT symmetry by comparison to hydrogen. With respect to absolute precision, transitions within the ground-state hyperfine structure (GS-HFS) are most appealing by virtue of their small energy separation. ASACUSA proposed employing a beam of cold antihydrogen atoms in a Rabi-type experiment to determine the GS-HFS in a field-free region. Here we present a measurement of the zero-field hydrogen GS-HFS using the spectroscopy apparatus of ASACUSA' s antihydrogen experiment. The measured value of nu_HF=1 420 405 748.4(3.4)(1.6) Hz with a relative precision of 2.7 × 10(−9) constitutes the most precise determination of this quantity in a beam and verifies the developed spectroscopy methods for the antihydrogen HFS experiment to the ppb level. Together with the recently presented observation of antihydrogen atoms 2.7 m downstream of the production region, the prerequisites for a measurement with antihydrogen are no...

  19. Absorption spectroscopy characterization measurements of a laser-produced Na atomic beam

    Energy Technology Data Exchange (ETDEWEB)

    Ching, C.H.; Bailey, J.E.; Lake, P.W.; Filuk, A.B.; Adams, R.G.; McKenney, J.

    1996-06-01

    This work describes a pulsed Na atomic beam source developed for spectroscopic diagnosis of a high-power ion diode on the Particle Beam Fusion Accelerator II. The goal is to produce a {approximately} 10{sup 12}-cm{sup {minus}3}-density Na atomic beam that can be injected into the diode acceleration gap to measure electric and magnetic fields from the Stark and Zeeman effects through laser-induced-fluorescence or absorption spectroscopy. A {approximately} 10 ns fwhm, 1.06 {micro}m, 0.6 J/cm{sup 2} laser incident through a glass slide heats a Na-bearing thin film, creating a plasma that generates a sodium vapor plume. A {approximately} 1 {micro}sec fwhm dye laser beam tuned to 5,890 {angstrom} is used for absorption measurement of the Na I resonant doublet by viewing parallel to the film surface. The dye laser light is coupled through a fiber to a spectrograph with a time-integrated CCD camera. A two-dimensional mapping of the Na vapor density is obtained through absorption measurements at different spatial locations. Time-of-flight and Doppler broadening of the absorption with {approximately} 0.1 {angstrom} spectral resolution indicate that the Na neutral vapor temperature is about 0.5 to 2 eV. Laser-induced-fluorescence from {approximately} 1 {times} 10{sup 12}-cm{sup {minus}3} Na I 3s-3p lines observed with a streaked spectrograph provides a signal level sufficient for {approximately} 0.06 {angstrom} wavelength shift measurements in a mock-up of an ion diode experiment.

  20. In-beam measurements of sub-nanosecond nuclear lifetimes with a mixed array of HPGe and LaBr{sub 3}:Ce detectors

    Energy Technology Data Exchange (ETDEWEB)

    Marginean, N.; Bucurescu, D.; Cata-Danil, G.; Cata-Danil, I.; Deleanu, D.; Filipescu, D.; Ghita, D.; Glodariu, T.; Ivascu, M.; Mihai, C.; Marginean, R.; Negret, A.; Pascu, S.; Sava, T.; Stroe, L.; Suliman, G.; Zamfir, N.V. [Horia Hulubei National Institute of Physics and Nuclear Engineering (IFIN-HH), Bucharest (Romania); Balabanski, D.L.; Atanasova, L.; Detistov, P. [Bulgarian Academy of Sciences, Institute for Nuclear Research and Nuclear Energy (INRNE), Sofia (Bulgaria); Lalkovski, S.; Deyanova, G.; Gladnishki, K.A.; Kisyov, S.; Radulov, D. [St. Kliment Ohridski University, Sofia (Bulgaria); Daugas, J.M. [CEA, DAM, DIF, Arpajon (France); Georgiev, G.; Lozeva, R. [CSNSM, Orsay (France)

    2010-12-15

    A fast-timing method to determine lifetimes of nuclear states in the sub-nanosecond domain is presented. It is based on in-beam measurements of triple-gamma coincidences in heavy-ion fusion-evaporation reactions, performed with an array of HPGe and LaBr{sub 3}:Ce detectors. The high-energy resolution HPGe detectors are used to define de-exciting cascades, while the fast LaBr{sub 3}:Ce detectors are used to determine the decay time spectra of selected levels fed by these cascades. A special method to treat the time information of an array of fast detectors is employed in order to fully use the efficiency of the array. Two measurements are presented to illustrate the method: a re-determination of the known half-life T{sub 1/2}=0.7 ns of the E{sub x}=205 keV, J{sup {pi}}=7/2{sup +} level in {sup 107}Cd (test experiment), and the determination of a half-life T{sub 1/2}=47 ps for the E{sub x}=367 keV, J{sup {pi}}=3/2{sup +} state of {sup 199}Tl. (orig.)

  1. Chemical states of localized Fe atoms in ethylene matrices using in-beam Mössbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Y., E-mail: kyoshio@pc.uec.ac.jp [University of Electro-Communications, Graduate School of Engineering Science (Japan); Yamada, Y. [Tokyo University of Science, Department of Chemistry (Japan); Tanigawa, S. [University of Electro-Communications, Graduate School of Engineering Science (Japan); Mihara, M. [Osaka University, Graduate School of Science (Japan); Kubo, M. K. [International Christian University, Division of Arts and Sciences (Japan); Sato, W. [Kanazawa University, Institute of Science and Engineering (Japan); Miyazaki, J. [Tokyo University of Agriculture and Technology, Department of Chemical Engineering (Japan); Nagatomo, T. [RIKEN, Nishina Center for Accelerator-Based Science (Japan); Sato, Y.; Natori, D.; Suzuki, M. [University of Electro-Communications, Graduate School of Engineering Science (Japan); Kobayashi, J. [International Christian University, Division of Arts and Sciences (Japan); Sato, S.; Kitagawa, A. [National Institute of Radiological Science (Japan)

    2016-12-15

    The reaction products of isolated single iron atoms in a low concentration matrix of ethylene were studied using in-beam Mössbauer spectroscopy with a short-lived {sup 57}Mn (T{sub 1/2}=1.45 m) beam. The in-beam Mössbauer spectrum of {sup 57}Fe arising from {sup 57}Mn in a matrix of ethylene and argon measured at 16 K was analyzed with four components. Density functional theory calculations were carried out to confirm the assignments. It was suggested that the reaction produced monoiron species of Fe(C {sub 2}H{sub 4}) with a spin state of S = 2.

  2. Development of beam emission spectroscopy for turbulence transport study in Heliotron J

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, S., E-mail: kobayashi@iae.kyoto-u.ac.jp; Ohshima, S.; Kado, S.; Nagasaki, K.; Okada, H.; Minami, T.; Yamamoto, S.; Konoshima, S.; Mizuuchi, T. [Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan); Matsuda, H.; Lu, X. X.; Kokubu, D.; Nakamura, Y.; Ishizawa, A.; Otani, Y. [Graduate School of Energy Science, Kyoto University, Uji, Kyoto 611-0011 (Japan); Ida, K.; Kobayashi, T.; Yoshinuma, M.; Oishi, T.; Kenmochi, N. [National Institute for Fusion Science, Oroshi-cho 322-6, Toki, Gifu 509-5292 (Japan)

    2016-11-15

    This paper describes the development study of the beam emission spectroscopy (BES) for the turbulent transport study in Heliotron J. Modification of the sightlines (10 × 4 for edge and 10 × 2 for edge) enables us to obtain 2-dimensional BES imaging. The cooling effect on the reduction in the electrical noise of avalanche photodiode (APD) assembly has been investigated using a refrigerant cooling system. When the temperature of the APD element has set to be −20 °C, the electrical noise can be reduced more than 50%. The measurement error of the phase difference in the case of low signal level has been tested by two light-emitting diode lamps. The APD cooling has an effect to improve the measurement error at the low signal level of APD.

  3. Comparison endpoint study of process plasma and secondary electron beam exciter optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Stephan Thamban, P. L.; Yun, Stuart; Padron-Wells, Gabriel; Hosch, Jimmy W.; Goeckner, Matthew J. [Department of Mechanical Engineering, University of Texas at Dallas, 800W Campbell Road, Richardson, Texas 75080 (United States); Department of Electrical Engineering, University of Texas at Dallas, 800W Campbell Road, Richardson, Texas 75080 (United States); Verity Instruments, Inc., 2901 Eisenhower Street, Carrollton, Texas 75007 (United States); Department of Mathematical Sciences, University of Texas at Dallas, 800 W Campbell Road, Richardson, Texas 75080 (United States)

    2012-11-15

    Traditionally process plasmas are often studied and monitored by optical emission spectroscopy. Here, the authors compare experimental measurements from a secondary electron beam excitation and direct process plasma excitation to discuss and illustrate its distinctiveness in the study of process plasmas. They present results that show excitations of etch process effluents in a SF{sub 6} discharge and endpoint detection capabilities in dark plasma process conditions. In SF{sub 6} discharges, a band around 300 nm, not visible in process emission, is observed and it can serve as a good indicator of etch product emission during polysilicon etches. Based on prior work reported in literature the authors believe this band is due to SiF{sub 4} gas phase species.

  4. Development of beam emission spectroscopy for turbulence transport study in Heliotron J

    Science.gov (United States)

    Kobayashi, S.; Ohshima, S.; Matsuda, H.; Lu, X. X.; Kokubu, D.; Ida, K.; Kobayashi, T.; Yoshinuma, M.; Kado, S.; Oishi, T.; Nagasaki, K.; Okada, H.; Minami, T.; Yamamoto, S.; Nakamura, Y.; Ishizawa, A.; Kenmochi, N.; Otani, Y.; Konoshima, S.; Mizuuchi, T.

    2016-11-01

    This paper describes the development study of the beam emission spectroscopy (BES) for the turbulent transport study in Heliotron J. Modification of the sightlines (10 × 4 for edge and 10 × 2 for edge) enables us to obtain 2-dimensional BES imaging. The cooling effect on the reduction in the electrical noise of avalanche photodiode (APD) assembly has been investigated using a refrigerant cooling system. When the temperature of the APD element has set to be -20 °C, the electrical noise can be reduced more than 50%. The measurement error of the phase difference in the case of low signal level has been tested by two light-emitting diode lamps. The APD cooling has an effect to improve the measurement error at the low signal level of APD.

  5. A trap-based pulsed positron beam optimised for positronium laser spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, B. S., E-mail: ben.cooper.13@ucl.ac.uk; Alonso, A. M.; Deller, A.; Wall, T. E.; Cassidy, D. B. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2015-10-15

    We describe a pulsed positron beam that is optimised for positronium (Ps) laser-spectroscopy experiments. The system is based on a two-stage Surko-type buffer gas trap that produces 4 ns wide pulses containing up to 5 × 10{sup 5} positrons at a rate of 0.5-10 Hz. By implanting positrons from the trap into a suitable target material, a dilute positronium gas with an initial density of the order of 10{sup 7} cm{sup −3} is created in vacuum. This is then probed with pulsed (ns) laser systems, where various Ps-laser interactions have been observed via changes in Ps annihilation rates using a fast gamma ray detector. We demonstrate the capabilities of the apparatus and detection methodology via the observation of Rydberg positronium atoms with principal quantum numbers ranging from 11 to 22 and the Stark broadening of the n = 2 → 11 transition in electric fields.

  6. Ion rotational velocity of a field-reversed configuration plasma measured by neutral beam probe spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Y.; Tanjyo, M.; Ohi, S.; Goto, S.; Ishimura, T.

    1987-01-01

    The ion rotational angular velocity ..cap omega.. and the ion temperature T/sub i/ of a translated field-reversed configuration (FRC) plasma are measured using neutral beam probe spectroscopy. The value of ..cap omega.. is --(1.0--1.2) x ..cap omega..* at the onset time of the n = 2 rotational instability, where ..cap omega..* is the ion diamagnetic frequency for a rigid-rotor equilibrium. The ion rotational direction is the same as the ion diamagnetic direction. The value of ..cap omega.. is smaller than the angular frequency ..omega../sub re/ of the n = 2 instability, which can yield experimental evidence of the ion kinetic effects on the n = 2 instability in the FRC plasma. When the octupole field is applied to the plasma in order to suppress the n = 2 deformation, ..cap omega.. is slightly reduced. The ion temperature T/sub i/ is --70 eV at the onset time of the n = 2 instability.

  7. In beam {gamma}-ray spectroscopy of the odd-odd nucleus {sup 144}Tb

    Energy Technology Data Exchange (ETDEWEB)

    Sferrazza, M. [Padua Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Padua (Italy)]|[Cambridge Univ. (United Kingdom). Cavendish Lab.; Cardona, M.A. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Bazzacco, D. [Padua Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Padua (Italy); Lunardi, S. [Padua Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Padua (Italy); Maglione, E. [Padua Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Padua (Italy); De Angelis, G. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro

    1996-03-01

    The level scheme of the N=79 nucleus {sup 144}Tb was investigated via in beam {gamma}-ray spectroscopy using the {sup 112}Sn({sup 35}Cl,n2p), {sup 116}Sn({sup 32}S,3np) and {sup 89}Y({sup 58}Ni,2np) reactions. States up to I{approx}20 and E{sub x}{approx}5 MeV were established above the 6{sup -} {beta}{sup +} decaying isomer. Two new isomers with half-life of 0.67(6) {mu}s and 2.8(3) {mu}s were identified. The level scheme of {sup 144}Tb is interpreted in the framework of the spherical shell model with a few valence nucleons outside the {sup 146}Gd core. (orig.)

  8. The applications of in situ electron energy loss spectroscopy to the study of electron beam nanofabrication.

    Science.gov (United States)

    Chen, Shiahn J; Howitt, David G; Gierhart, Brian C; Smith, Rosemary L; Collins, Scott D

    2009-06-01

    An in situ electron energy loss spectroscopy (EELS) technique has been developed to investigate the dynamic processes associated with electron-beam nanofabrication on thin membranes. In this article, practical applications germane to e-beam nanofabrication are illustrated with a case study of the drilling of nanometer-sized pores in silicon nitride membranes. This technique involves successive acquisitions of the plasmon-loss and the core-level ionization-loss spectra in real time, both of which provide the information regarding the hole-drilling kinetics, including two respective rates for total mass loss, individual nitrogen and silicon element depletion, and the change of the atomic bonding environment. In addition, the in situ EELS also provides an alternative method for endpoint detection with a potentially higher time resolution than by imaging. On the basis of the time evolution of in situ EELS spectra, a qualitative working model combining knock-on sputtering, irradiation-induced mass transport, and phase separation can be proposed.

  9. Confocal microscopy with cylindrical vector beams and spectroscopy of single silicon nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chizhik, Anna; Chizhik, Alexey; Baer, Sebastian; Meixner, Alfred [Inst. of Physical and Theor. Chem., Univ. of Tuebingen (Germany); Schmidt, Torsten; Huisken, Friedrich [Lab. Astrophys., Group of the MPI for Astronomy at the Inst. of Solid State Phys., Univ. of Jena (Germany)

    2010-07-01

    Being the paramount material silicon revealed new magnificent outlooks with the development of nanotechnology. During last years the research on silicon nanoparticles has been one of the hottest topics. However, many of their photoluminescence (PL) properties are still unclear. Combining the confocal microscopy, spectroscopy, and cylindrical vector beams (also known as higher order laser modes) we reveal new details of fundamental PL properties of Si/SiO{sub 2} core-shell systems and hollow SiO{sub 2} shells. We show that the emission from both systems may originate from defects of the SiO{sub 2} structure or at the Si-SiO{sub 2} interface. This result demonstrates the effect of ''break-down'' of the quantum confinement in small Si/SiO{sub 2} nanoparticles, which limits the PL tunability and thus, applications in Si optical nanostructures, especially in the short wavelength range. Using the technique of cylindrical vector beams we demonstrate that SiO{sub 2} nanoparticles and Si/SiO{sub 2} nanocrystals, where the PL originates from defects, possess linear transition dipole moment (TDM). Moreover, we precisely determine the 3-dimensional orientation of single nanoparticle TDM and show such dynamical effects as TDM sudden flipping.

  10. Electrochemical impedance spectroscopy on nanostructured carbon electrodes grown by supersonic cluster beam deposition

    Energy Technology Data Exchange (ETDEWEB)

    Bettini, Luca Giacomo; Bardizza, Giorgio; Podesta, Alessandro; Milani, Paolo; Piseri, Paolo, E-mail: piseri@mi.infn.it [Universita degli Studi di Milano, Dipartimento di Fisica and CIMaINa (Italy)

    2013-02-15

    Nanostructured porous films of carbon with density of about 0.5 g/cm{sup 3} and 200 nm thickness were deposited at room temperature by supersonic cluster beam deposition (SCBD) from carbon clusters formed in the gas phase. Carbon film surface topography, determined by atomic force microscopy, reveals a surface roughness of 16 nm and a granular morphology arising from the low kinetic energy ballistic deposition regime. The material is characterized by a highly disordered carbon structure with predominant sp2 hybridization as evidenced by Raman spectroscopy. The interface properties of nanostructured carbon electrodes were investigated by cyclic voltammetry and electrochemical impedance spectroscopy employing KOH 1 M solution as aqueous electrolyte. An increase of the double layer capacitance is observed when the electrodes are heat treated in air or when a nanostructured nickel layer deposited by SCBD on top of a sputter deposited film of the same metal is employed as a current collector instead of a plain metallic film. This enhancement is consistent with an improved charge injection in the active material and is ascribed to the modification of the electrical contact at the interface between the carbon and the metal current collector. Specific capacitance values up to 120 F/g have been measured for the electrodes with nanostructured metal/carbon interface.

  11. Location and size of nanoscale free-volume holes in crosslinked- polytetrafluoroethylene-based graft-type polymer electrolyte membranes determined by positron annihilation lifetime spectroscopy

    Science.gov (United States)

    Sawada, Shin-ichi; Yabuuchi, Atsushi; Maekawa, Masaki; Kawasuso, Atsuo; Maekawa, Yasunari

    2013-06-01

    The location and size of nanoscale free-volume holes (nanoholes) in graft-type polymer electrolyte membranes (PEMs), which were prepared by radiation-induced graft polymerization (grafting) of styrene into crosslinked-polytetrafluoroethylene (cPTFE) films and subsequent sulfonation, were investigated using positron annihilation lifetime (PAL) spectroscopy. The PAL spectra of the PEMs indicated the existence of two types of ortho-positronium (o-Ps) species, corresponding to nanoholes with volumes of 0.11 and 0.38 nm3. A comparison of the PAL data of the PEMs with that of the precursor original cPTFE and polystyrene-grafted films demonstrated the probability that the smaller holes were located in both the PTFE crystalline phases and the poly(styrene sulfonic acid) graft regions, whereas the larger holes are potentially localized in the PTFE amorphous phases. Taking into account both the size and the location of the nanoholes, it was concluded that gas transport through the larger holes in the amorphous PTFE phases was dominant over permeation through the smaller holes in the PTFE crystals and grafted regions.

  12. Microstructure variation in fused silica irradiated by different fluence of UV laser pulses with positron annihilation lifetime and Raman scattering spectroscopy

    Science.gov (United States)

    Li, Chunhong; Zheng, Wanguo; Zhu, Qihua; Chen, Jun; Wang, B. Y.; Ju, Xin

    2016-10-01

    We present an original study on the non-destructive evaluation of the microstructure evolution of fused silica induced by pulsed UV laser irradiation at low fluence (less than 50% Fth). Positron annihilation spectroscopy discloses that the spatial size of the vacancy cluster is increased exponentially with the linearly elevated laser fluence. Particularly, the vacancy cluster size in bulk silica is significantly increased by 14.5% after irradiated by pulsed 355 nm laser at F = 14 J/cm2 (50% Fth), while the void size varies only ∼2%. UV laser-excited Raman results suggest that the bond length and average bond angle of Sisbnd Osbnd Si bridging bond are both slightly reduced. Results reveals that the rearrangement process of (Sisbnd O)n fold rings and breakage of the Sisbnd O bridging bond in bulk silica occurred during pulsed UV laser irradiation. The micro-structural changes were taken together to clarify the effect of sub-threshold laser fluence on material stability of silica glass. The obtained data provide important information for studying material stability and controlling the lifetime of fused silica optics for high power laser system.

  13. CAESAR-A high-efficiency CsI(Na) scintillator array for in-beam {gamma}-ray spectroscopy with fast rare-isotope beams

    Energy Technology Data Exchange (ETDEWEB)

    Weisshaar, D., E-mail: weisshaa@nscl.msu.ed [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Gade, A.; Glasmacher, T. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Grinyer, G.F.; Bazin, D.; Adrich, P. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Baugher, T.; Cook, J.M. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Diget, C.A. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); McDaniel, S.; Ratkiewicz, A.; Siwek, K.P.; Walsh, K.A. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

    2010-12-21

    We report on the construction and commissioning of the high-efficiency CAESium-iodide scintillator ARray CAESAR, a device designed for in-beam {gamma}-ray spectroscopy experiments utilizing fast beams of rare isotopes at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU). CAESAR consists of 192 CsI(Na) crystals, totaling 290 kg of active scintillator material. For 1 MeV {gamma} rays, a full-energy-peak efficiency of 35% is achieved at an in-beam energy resolution of better than 10% FWHM after event-by-event Doppler reconstruction of the {gamma} rays emitted by nuclei moving with velocities of v/c{approx}0.3-0.4. The spectral quality of the array allows for the identification of {gamma}-ray transitions with intensities of several 10 counts in the full-energy peak and thus opens new avenues for the study of the most exotic nuclei available at the NSCL for in-beam spectroscopy.

  14. Gamma ray tracking with the AGATA demonstrator. A novel approach for in-beam spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Birkenbach, Benedikt

    2014-04-11

    PRISMA. The γ-rays were detected with the AGATA demonstrator consisting of five AGATA triple cluster detectors. An additional micro channel plate detector for particle detection was mounted inside the scattering chamber in order to request kinematic coincidences. The analysis procedures for the two complex sub-detectors AGATA and PRISMA were extended and adapted to the specific requirements of this new approach for actinide spectroscopy. First the complex analysis of the magnetic spectrometer PRISMA and solutions for unexpected detector behaviour like time drifts and aberration corrections are described. As a result the individual isotopes of elements from Barium to Tellurium were identified confirming the very high quality of the PRISMA spectrometer and its design parameters. The analysis of the γ-ray spectra comprised a detailed PSA and GRT analysis of the AGATA demonstrator. This analysis included also data analysis developments for the AGATA collaboration. The data of the AGATA demonstrator, the PRISMA spectrometer and the ancillary detectors were merged to obtain background free Doppler corrected spectra for the beam- and target-like reaction products. The simultaneous Doppler correction for beam and target-like ions included an elaborate optimization procedure for unobservable experimental parameters. The γ-ray spectra for the individual isotopes is consistent with the isotope identification of the PRISMA analysis. For the beam like particles γ-ray spectra of the isotopes {sup 128-139}Xe are presented and discussed. For the target like nuclei γ-ray spectra of the isotopes {sup 236-240}U are deduced. By gating on the remaining excitation energy after the multi-nucleon transfer reaction the neutron evaporation and fission of the excited actinide nuclei were suppressed. Coincidences between AGATA and PRISMA were exploited for the first time together with the particle coincidence between beam- and target-like nuclei. These triple coincidences allowed further

  15. Parameters Optimization of Laser-Induced Breakdown Spectroscopy Experimental Setup for the Case with Beam Expander

    Science.gov (United States)

    Wang, Xin; Zhang, Lei; Fan, Juanjuan; Li, Yufang; Gong, Yao; Dong, Lei; Ma, Weiguang; Yin, Wangbao; Jia, Suotang

    2015-11-01

    Improvement of measurement precision and repeatability is one of the issues currently faced by the laser-induced breakdown spectroscopy (LIBS) technique, which is expected to be capable of precise and accurate quantitative analysis. It was found that there was great potential to improve the signal quality and repeatability by reducing the laser beam divergence angle using a suitable beam expander (BE). In the present work, the influences of several experimental parameters for the case with BE are studied in order to optimize the analytical performances: the signal to noise ratio (SNR) and the relative standard deviation (RSD). We demonstrate that by selecting the optimal experimental parameters, the BE-included LIBS setup can give higher SNR and lower RSD values of the line intensity normalized by the whole spectrum area. For validation purposes, support vector machine (SVM) regression combined with principal component analysis (PCA) was used to establish a calibration model to realize the quantitative analysis of the ash content. Good agreement has been found between the laboratory measurement results from the LIBS method and those from the traditional method. The measurement accuracy presented here for ash content analysis is estimated to be 0.31%, while the average relative error is 2.36%. supported by the 973 Program of China (No. 2012CB921603), National Natural Science Foundation of China (Nos. 61475093, 61127017, 61178009, 61108030, 61378047, 61275213, 61475093, and 61205216), the National Key Technology R&D Program of China (No. 2013BAC14B01), the Shanxi Natural Science Foundation (Nos. 2013021004-1 and 2012021022-1), the Shanxi Scholarship Council of China (Nos. 2013-011 and 2013-01), and the Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi, China

  16. QSO Lifetimes

    CERN Document Server

    Martini, P

    2003-01-01

    The QSO lifetime t_Q is one of the most fundamental quantities for understanding black hole and QSO evolution, yet it remains uncertain by several orders of magnitude. If t_Q is long, then only a small fraction of galaxies went through a luminous QSO phase. In contrast, a short lifetime would require most galaxies today to have undergone a QSO phase in their youth. The current best estimates or constraints on t_Q from black hole demographics and the radiative properties of QSOs vary from at least 10^6 to 10^8 years. This broad range still allows both possibilities: that QSOs were either a rare or a common stage of galaxy evolution. These constraints also do not rule out the possibility that QSO activity is episodic, with individual active periods much shorter than the total active lifetime. In the next few years a variety of additional observational constraints on the lifetimes of QSOs will become available, including clustering measurements and the proximity effect. These new constraints can potentially dete...

  17. Speciation of uranium and doping induced defects in Gd1.98U0.02Zr2O7: Photoluminescence, X-ray photoelectron and positron annihilation lifetime spectroscopy

    Science.gov (United States)

    Gupta, Santosh K.; Reghukumar, C.; Pathak, Nimai; Sudarshan, K.; Tyagi, D.; Mohapatra, M.; Pujari, P. K.; Kadam, R. M.

    2017-02-01

    Based on photoluminescence spectroscopy it was inferred that uranium stabilizes as both U(IV) as well as U(VI) in Gd2Zr2O7 which was also corroborated using X-ray photo electron spectroscopy (XPS). Absence of equidistant vibronic structure in emission spectrum of Gd1.98U0.02Zr2O7 confirmed that U(VI) stabilizes in the form of UO66-. Based on luminescence lifetime it was inferred that majority of UO66- stabilizes at both Gd3+/Zr4+ whereas U4+ stabilizes only at Zr4+ sites. The positron lifetime doesn't change on uranium doping indicating the formation of antisite defect. Infact it is this antisite defect in Gd1.98U0.02Zr2O7 which favours the stabilization of its fluorite phase.

  18. An atomic beam of 6Li — 7Li for high resolution spectroscopy from matrix isolation sublimation

    Science.gov (United States)

    Oliveira, A. N.; Sacramento, R. L.; Silva, B. A.; Uhlmann, F. O.; Wolff, W.; Cesar, C. L.

    2016-07-01

    We propose the Matrix Isolation Sublimation (MlSu) technique for generating cold lithium atoms for the measurement of the 6Li - 7Li isotope shift in D1 and D2 transitions. The technique is capable of generating cold 6Li and 7Li beams at 4 K with forward velocity of 125 m/s. Using this beam we offer a distinguished source of lithium atoms for transitions measurements, adding a new possibility to make high resolution spectroscopy towards improving the experimental checks of the theory.

  19. Nuclear Ground State Properties in Strontium by Fast Beam Laser Spectroscopy

    CERN Multimedia

    2002-01-01

    Hyperfine structures and isotope shifts of strontium isotopes with A=78 to A=100 were measured by collinear fast beam laser spectroscopy. Nuclear spins, moments and changes in mean square charge radii are extracted from the data. The spins and moments of most of the odd isotopes are explained in the framework of the single particle model. The changes in mean square charge radii show a decrease with increasing neutron number below the N=50 shell closure. Above N=50 the charge radii increase regularly up to N=59 before revealing a strong discontinuity, indicating the onset of strong ground state deformation. A comparison of the droplet model shows that for the transitional isotopes below and above N=50, the zero point quadrupole motion describes part of the observed shell effect. Calculations carried out in the Hartree-Fock plus BCS model suggest an additional change in the surface region of the charge distribution at spherical shape. From these calculations it is furthermore proposed, that the isotopes $^7

  20. Helium implanted Eurofer97 characterized by positron beam Doppler broadening and Thermal Desorption Spectroscopy

    Science.gov (United States)

    Carvalho, I.; Schut, H.; Fedorov, A.; Luzginova, N.; Desgardin, P.; Sietsma, J.

    2013-11-01

    Reduced Activation Ferritic/Martensitic steels are being extensively studied because of their foreseen application in fusion and Generation IV fission reactors. To produce irradiation induced defects, Eurofer97 samples were implanted with helium at energies of 500 keV and 2 MeV and doses of 1 × 1015-1016 He/cm2, creating atomic displacements in the range 0.07-0.08 dpa. The implantation induced defects were characterized by positron beam Doppler Broadening (DB) and Thermal Desorption Spectroscopy (TDS). Results show that up to ˜600 K peaks that can be attributed to He desorption from overpressured HenVm (n > m) clusters and vacancy assisted mechanism in the case of helium in the substitutional position. The temperature range 600-1200 K is related to the formation of larger clusters HenVm (n < m). The dissociation of the HeV and the phase transition attributed to a sharp peak in the TDS spectra at 1200 K. Above this temperature, the release of helium from bubbles is observed.

  1. Relativistic atomic beam spectroscopy 2. Appendix A: Progress report, July 1, 1989--June 30, 1992: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, H.C.

    1992-07-01

    This work supported by the Division of Chemical Sciences, Office of Basic Energy Services, Office of Energy Research, US Department of Energy during the period July 1, 1989 to June 30, 1992, resulted in noteworthy scientific results in three categories which we shall discuss in turn: The spectroscopy of high-lying doubly-excited states of H{sup {minus}}, interactions with thin foils, and multiphoton processes. Radiological safety concerns and slow beam studies are also briefly discussed.

  2. Compact, accurate description of diagnostic neutral beam propagation and attenuation in a high temperature plasma for charge exchange recombination spectroscopy analysis.

    Science.gov (United States)

    Bespamyatnov, Igor O; Rowan, William L; Granetz, Robert S

    2008-10-01

    Charge exchange recombination spectroscopy on Alcator C-Mod relies on the use of the diagnostic neutral beam injector as a source of neutral particles which penetrate deep into the plasma. It employs the emission resulting from the interaction of the beam atoms with fully ionized impurity ions. To interpret the emission from a given point in the plasma as the density of emitting impurity ions, the density of beam atoms must be known. Here, an analysis of beam propagation is described which yields the beam density profile throughout the beam trajectory from the neutral beam injector to the core of the plasma. The analysis includes the effects of beam formation, attenuation in the neutral gas surrounding the plasma, and attenuation in the plasma. In the course of this work, a numerical simulation and an analytical approximation for beam divergence are developed. The description is made sufficiently compact to yield accurate results in a time consistent with between-shot analysis.

  3. Revised Landé gJ-factors of some 141Pr II levels using collinear laser ion beam spectroscopy

    Science.gov (United States)

    Werbowy, S.; Windholz, L.

    2017-01-01

    The Zeeman effect of singly ionized praseodymium spectral lines was studied at small magnetic fields up to 334 G, using the high-resolution spectroscopic method of collinear laser-ion-beam spectroscopy (CLIBS), where a collimated fast ion beam is superimposed with a counter propagating laser beam tuned to the desired transition. This nearly Doppler-effect-free technique enables to observe linewidths as low as 100 MHz and thus to record the Zeeman patterns of the hyperfine structure of the investigated spectral lines. From the Zeeman patterns of 21 lines of Pr II lines in the range 570.45-609.038 nm we have re-determined the Landé gJ-factors of 14 levels of the f3 dodd and 16 levels of the f3 p and f2d2even configurations. The obtained experimental Landé factors are compared with available earlier measurements as well as with theoretical calculations.

  4. Self-corrected sensors based on atomic absorption spectroscopy for atom flux measurements in molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Du, Y., E-mail: yingge.du@pnnl.gov, E-mail: scott.chambers@pnnl.gov; Liyu, A. V. [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Droubay, T. C.; Chambers, S. A., E-mail: yingge.du@pnnl.gov, E-mail: scott.chambers@pnnl.gov [Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Li, G. [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

    2014-04-21

    A high sensitivity atom flux sensor based on atomic absorption spectroscopy has been designed and implemented to control electron beam evaporators and effusion cells in a molecular beam epitaxy system. Using a high-resolution spectrometer and a two-dimensional charge coupled device detector in a double-beam configuration, we employ either a non-resonant line or a resonant line with low cross section from the same hollow cathode lamp as the reference for nearly perfect background correction and baseline drift removal. This setup also significantly shortens the warm-up time needed compared to other sensor technologies and drastically reduces the noise coming from the surrounding environment. In addition, the high-resolution spectrometer allows the most sensitive resonant line to be isolated and used to provide excellent signal-to-noise ratio.

  5. Self-corrected Sensors Based On Atomic Absorption Spectroscopy For Atom Flux Measurements In Molecular Beam Epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Du, Yingge; Droubay, Timothy C.; Liyu, Andrey V.; Li, Guosheng; Chambers, Scott A.

    2014-04-24

    A high sensitivity atom flux sensor based on atomic absorption spectroscopy has been designed and implemented to control electron beam evaporators and effusion cells in a molecular beam epitaxy system. Using a high-resolution spectrometer and a two-dimensional charge coupled device (CCD) detector in a double-beam configuration, we employ a non-resonant line or a resonant line with lower absorbance from the same hollow cathode lamp as the reference for nearly perfect background correction and baseline drift removal. This setup also significantly shortens the warm-up time needed compared to other sensor technologies and drastically reduces the noise coming from the surrounding environment. In addition, the high-resolution spectrometer allows the most sensitive resonant line to be isolated and used to provide excellent signal-to-noise ratio.

  6. Self-corrected sensors based on atomic absorption spectroscopy for atom flux measurements in molecular beam epitaxy

    Science.gov (United States)

    Du, Y.; Droubay, T. C.; Liyu, A. V.; Li, G.; Chambers, S. A.

    2014-04-01

    A high sensitivity atom flux sensor based on atomic absorption spectroscopy has been designed and implemented to control electron beam evaporators and effusion cells in a molecular beam epitaxy system. Using a high-resolution spectrometer and a two-dimensional charge coupled device detector in a double-beam configuration, we employ either a non-resonant line or a resonant line with low cross section from the same hollow cathode lamp as the reference for nearly perfect background correction and baseline drift removal. This setup also significantly shortens the warm-up time needed compared to other sensor technologies and drastically reduces the noise coming from the surrounding environment. In addition, the high-resolution spectrometer allows the most sensitive resonant line to be isolated and used to provide excellent signal-to-noise ratio.

  7. Study of defects in implanted silica glass by depth profiling Positron Annihilation Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Brusa, R.S., E-mail: brusa@science.unitn.i [CNISM, Dipartimento di Fisica, Universita di Trento, Via Sommarive 14, I-38050 Povo, Trento (Italy); Mariazzi, S. [CNISM, Dipartimento di Fisica, Universita di Trento, Via Sommarive 14, I-38050 Povo, Trento (Italy); Ravelli, L. [CNISM, Dipartimento di Fisica, Universita di Trento, Via Sommarive 14, I-38050 Povo, Trento (Italy); Institut fuer Angewandte Physik und Messtechnik, Universitaet der Bunderswehr Muenchen, 85577 Neubiberg (Germany); Mazzoldi, P.; Mattei, G. [CNISM, Dipartimento di Fisica, Universita di Padova, Via Marzolo 8, 35131 Padova (Italy); Egger, W. [Institut fuer Angewandte Physik und Messtechnik, Universitaet der Bunderswehr Muenchen, 85577 Neubiberg (Germany); Hugenschmidt, C.; Loewe, B.; Pikart, P. [Physik Department E21 and FRMII, Technische Universitaet Muenchen, 85747 Garching (Germany); Macchi, C.; Somoza, A. [IFIMAT, UNCentro and CICPBA, Pinto 399, B7000GHG Tandil (Argentina)

    2010-10-01

    Positron Annihilation Spectroscopy (PAS) performed with continuous and pulsed positron beams allows to characterize the size of the intrinsic nano-voids in silica glass, their in depth modification after ion implantation and their decoration by implanted ions. Three complementary PAS techniques, lifetime spectroscopy (LS), Doppler broadening spectroscopy (DBS) and coincidence Doppler broadening spectroscopy (CDBS) will be illustrated by presenting, as a case study, measurements obtained on virgin and gold implanted silica glass.

  8. Time-resolved thermal lens spectroscopy with a single-pulsed laser excitation beam: an analytical model for dual-beam mode-mismatched experiments.

    Science.gov (United States)

    Sabaeian, Mohammad; Rezaei, Hamidreza; Ghalambor-Dezfouli, Abdolmohammad

    2017-02-01

    Pulsed laser beam excitations are more commonly used in thermal lens spectroscopy (TLS) than continuous-wave (CW) ones, because CW excitations limit the measurement to linear absorption processes [J. Opt. A5, 256 (2003)]. In this work, we present a new and full analytical model for a single-pulsed laser excitation dual-beam mode-mismatched TLS for low absorption solid-state and liquid samples. Our model has been based on a new solution of time-dependent heat equation for a finite-radius cylindrical sample exposed to a single-pulsed excitation laser beam. For low absorbent samples, unlike previous models, all aberration terms associated in the thermal lens were taken into account in Fresnel integration. Besides, the model provides a full analytical mathematical expression for the temperature rise, normalized signal intensity, and Z-scan photothermal lens signal. The model was confirmed with experimental data of distilled deionized water with excellent agreement. Therefore, the model allows us to extract thermo-optical properties of samples in an analytical and more accurate way.

  9. Synchrotron VUV-UV and positron lifetime spectroscopy study of vacancy-type defects in reactor neutron-irradiated MgO·nAl2O3 (n = 2

    Directory of Open Access Journals (Sweden)

    Abu Zayed Mohammad Saliqur Rahman

    2016-12-01

    Full Text Available We investigated neutron-irradiation-induced point defects in spinel single crystals using a synchrotron VUV-UV source and positron lifetime spectroscopy. Photoexcitation (PE spectra near 230 nm and their corresponding photoluminescence (PL spectra at 475 nm were attributed to F-centers. With increasing irradiation temperature and fluence, PE efficiency and PL intensity decreased dramatically. Positron lifetimes (PLT of neutron-irradiated and non-irradiated samples were measured to identify the cation vacancies. A PLT measurement of 250 ps was obtained in a neutron-irradiated (20 K sample which is tentatively attributed to an aluminum monovacancy. Decreasing PLT with higher irradiation indicates the formation of oxygen-vacancy complex centers.

  10. A field programmable gate array-based time-resolved scaler for collinear laser spectroscopy with bunched radioactive potassium beams.

    Science.gov (United States)

    Rossi, D M; Minamisono, K; Barquest, B R; Bollen, G; Cooper, K; Davis, M; Hammerton, K; Hughes, M; Mantica, P F; Morrissey, D J; Ringle, R; Rodriguez, J A; Ryder, C A; Schwarz, S; Strum, R; Sumithrarachchi, C; Tarazona, D; Zhao, S

    2014-09-01

    A new data acquisition system including a Field Programmable Gate Array (FPGA) based time-resolved scaler was developed for laser-induced fluorescence and beam bunch coincidence measurements. The FPGA scaler was tested in a collinear laser-spectroscopy experiment on radioactive (37)K at the BEam COoler and LAser spectroscopy (BECOLA) facility at the National Superconducting Cyclotron Laboratory at Michigan State University. A 1.29 μs bunch width from the buncher and a bunch repetition rate of 2.5 Hz led to a background suppression factor of 3.1 × 10(5) in resonant photon detection measurements. The hyperfine structure of (37)K and its isotope shift relative to the stable (39)K were determined using 5 × 10(4) s(-1) (37)K ions injected into the BECOLA beam line. The obtained hyperfine coupling constants A((2)S(1/2)) = 120.3(1.4) MHz, A((2)P(1/2)) = 15.2(1.1) MHz, and A((2)P(3/2)) = 1.4(8) MHz, and the isotope shift δν(39, 37) = -264(3) MHz are consistent with the previously determined values, where available.

  11. A field programmable gate array-based time-resolved scaler for collinear laser spectroscopy with bunched radioactive potassium beams

    Science.gov (United States)

    Rossi, D. M.; Minamisono, K.; Barquest, B. R.; Bollen, G.; Cooper, K.; Davis, M.; Hammerton, K.; Hughes, M.; Mantica, P. F.; Morrissey, D. J.; Ringle, R.; Rodriguez, J. A.; Ryder, C. A.; Schwarz, S.; Strum, R.; Sumithrarachchi, C.; Tarazona, D.; Zhao, S.

    2014-09-01

    A new data acquisition system including a Field Programmable Gate Array (FPGA) based time-resolved scaler was developed for laser-induced fluorescence and beam bunch coincidence measurements. The FPGA scaler was tested in a collinear laser-spectroscopy experiment on radioactive 37K at the BEam COoler and LAser spectroscopy (BECOLA) facility at the National Superconducting Cyclotron Laboratory at Michigan State University. A 1.29 μs bunch width from the buncher and a bunch repetition rate of 2.5 Hz led to a background suppression factor of 3.1 × 105 in resonant photon detection measurements. The hyperfine structure of 37K and its isotope shift relative to the stable 39K were determined using 5 × 104 s-1 37K ions injected into the BECOLA beam line. The obtained hyperfine coupling constants A(2S1/2) = 120.3(1.4) MHz, A(2P1/2) = 15.2(1.1) MHz, and A(2P3/2) = 1.4(8) MHz, and the isotope shift δν39, 37 = -264(3) MHz are consistent with the previously determined values, where available.

  12. Integration of Correlative Raman microscopy in a dual beam FIB-SEM J. of Raman Spectroscopy

    NARCIS (Netherlands)

    Timmermans, Frank Jan; Liszka, B.; Lenferink, Aufrid T.M.; van Wolferen, Hendricus A.G.M.; Otto, Cornelis

    2016-01-01

    We present an integrated confocal Raman microscope in a focused ion beam scanning electron microscope (FIB SEM). The integrated system enables correlative Raman and electron microscopic analysis combined with focused ion beam sample modification on the same sample location. This provides new

  13. Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1968-01-01

    This booklet discusses spectroscopy, the study of absorption of radiation by matter, including X-ray, gamma-ray, microwave, mass spectroscopy, as well as others. Spectroscopy has produced more fundamental information to the study of the detailed structure of matter than any other tools.

  14. Comparative Studies on Effects of Acid Solutions on Aquatic Plants by Beam Deflection and Absorbance Spectroscopy Methods.

    Science.gov (United States)

    Wu, Xing-Zheng; Nie, Liangjiao; Inoue, Tomomi

    2015-01-01

    The beam deflection method and absorbance spectroscopy were applied to study effects of acid solutions on aquatic plants, and their results were compared. Aquatic plants Egeria densa and Ceratophyllum demersum L were used as model plants. In absorbance experiments, a piece of the plants was put in a beaker with 20 mL HCl solution, and absorbance of the HCl solution was measured every 30 min. In beam deflection experiments, a probe beam from a He-Ne laser was focused to a vicinity of the plants in a culture dish with HCl solution by an objective lens, and deflection signals of the probe beam were monitored by a position sensor. Absorbance spectra of the HCl solutions with immersing of the plants showed absorbance below 410 nm, suggesting that some compounds leaked from the plants into the HCl solutions. Changes of absorbance and deflection signals with immersion time were examined for different pH levels. The changing trends of the absorbance and deflection signals with time were similar, but the absorbance changes were delayed for about 2 - 3 h. The absorbance method could not detect the effect of the pH 5.0 HCl solutions on the aquatic plants, while the deflection method could.

  15. High-resolution optical spectroscopy with a buffer-gas-cooled beam of BaH molecules

    Science.gov (United States)

    Iwata, G. Z.; McNally, R. L.; Zelevinsky, T.

    2017-08-01

    Barium monohydride (BaH) is an attractive candidate for extending laser cooling and trapping techniques to diatomic hydrides. The apparatus and high-resolution optical spectroscopy presented here demonstrate progress toward this goal. A cryogenic buffer-gas-cooled molecular beam of BaH was constructed and characterized. Pulsed laser ablation into cryogenic helium buffer gas delivers ˜1 ×1010 molecules/sr/pulse in the X +2Σ (v''=0 ,N''=1 ) state of primary interest. More than 1 ×107 of these molecules per pulse enter the downstream science region with forward velocities below 100 m/s and transverse temperature of 0.1 K. This molecular beam enabled high-resolution optical spectra of BaH in quantum states relevant to laser slowing and cooling. The reported measurements include hyperfine structure and magnetic g factors in the X +2Σ , B +2Σ , and A 1/2 2Π states.

  16. Improved maximum entropy method for the analysis of fluorescence spectroscopy data: evaluating zero-time shift and assessing its effect on the determination of fluorescence lifetimes.

    Science.gov (United States)

    Esposito, Rosario; Mensitieri, Giuseppe; de Nicola, Sergio

    2015-12-21

    A new algorithm based on the Maximum Entropy Method (MEM) is proposed for recovering both the lifetime distribution and the zero-time shift from time-resolved fluorescence decay intensities. The developed algorithm allows the analysis of complex time decays through an iterative scheme based on entropy maximization and the Brent method to determine the minimum of the reduced chi-squared value as a function of the zero-time shift. The accuracy of this algorithm has been assessed through comparisons with simulated fluorescence decays both of multi-exponential and broad lifetime distributions for different values of the zero-time shift. The method is capable of recovering the zero-time shift with an accuracy greater than 0.2% over a time range of 2000 ps. The center and the width of the lifetime distributions are retrieved with relative discrepancies that are lower than 0.1% and 1% for the multi-exponential and continuous lifetime distributions, respectively. The MEM algorithm is experimentally validated by applying the method to fluorescence measurements of the time decays of the flavin adenine dinucleotide (FAD).

  17. Oxidation of nanostructured Ti films produced by low energy cluster beam deposition: An X-ray Photoelectron Spectroscopy characterization

    Energy Technology Data Exchange (ETDEWEB)

    Simone, Monica de, E-mail: desimone@tasc.infm.it [CNR-IOM Laboratorio TASC, Area Science Park Basovizza, 34149 Trieste (Italy); Snidero, Elena [CNR-IOM Laboratorio TASC, Area Science Park Basovizza, 34149 Trieste (Italy); Coreno, Marcello [CNR-IMIP, c/o Laboratorio TASC Area Science Park Basovizza, 34149 Trieste (Italy); Sincrotrone Trieste ScpA, Area Science Park Basovizza, 34149 Trieste (Italy); Bongiorno, Gero [Fondazione Filarete, v.le Ortles 22/4, 20139 Milano (Italy); Giorgetti, Luca [Istituto Europeo di Oncologia, Dip. di Oncologia Sperimentale, Via Adamello 16, 20139, Milano (Italy); Amati, Matteo [Sincrotrone Trieste ScpA, Area Science Park Basovizza, 34149 Trieste (Italy); Cepek, Cinzia [CNR-IOM Laboratorio TASC, Area Science Park Basovizza, 34149 Trieste (Italy)

    2012-05-01

    We used in-situ X-ray Photoelectron Spectroscopy (XPS) to study the oxidation process of a cluster-assembled metallic titanium film exposed to molecular oxygen at room temperature. The nanostructured film has been grown on a Si(111) substrate, in ultra high vacuum conditions, by coupling a supersonic cluster beam deposition system with an XPS experimental chamber. Our results show that upon in-situ oxygen exposure Ti{sup 3+} is the first oxidation state observed, followed by Ti{sup 4+}, whereas Ti{sup 2+} is practically absent during the whole process. Our results compare well with the existing literature on Ti films produced using other techniques.

  18. Reactive ion beam etching studies of tungsten with CF sub 4 /argon mixtures using ion scattering spectroscopy and SIMS

    Energy Technology Data Exchange (ETDEWEB)

    Cox, T.I.; Deshmukh, V.G.I. (Royal Signals and Radar Establishment, Malvern (UK)); Armour, D.G. (Salford Univ. (UK). Dept. of Electrical Engineering)

    1989-01-01

    Tungsten foil was bombarded at 550 eV with ion beams generated from CF{sub 4}/Ar gas mixtures. The chemical compositions of the bombarded surface and etch products were determined using Ion Scattering Spectroscopy and Secondary Ion Mass Spectrometry respectively. As the ratio CF{sub 4}/Ar was increased, the tungsten surface became covered with fluorine atoms. The products observed were positive ions of W, WF, and WF{sub 2}, with WF{sub 2} being only formed above a threshold concentration of CF{sub 4} in the gas mixture. (author).

  19. Method to obtain absolute impurity density profiles combining charge exchange and beam emission spectroscopy without absolute intensity calibrationa)

    Science.gov (United States)

    Kappatou, A.; Jaspers, R. J. E.; Delabie, E.; Marchuk, O.; Biel, W.; Jakobs, M. A.

    2012-10-01

    Investigation of impurity transport properties in tokamak plasmas is essential and a diagnostic that can provide information on the impurity content is required. Combining charge exchange recombination spectroscopy (CXRS) and beam emission spectroscopy (BES), absolute radial profiles of impurity densities can be obtained from the CXRS and BES intensities, electron density and CXRS and BES emission rates, without requiring any absolute calibration of the spectra. The technique is demonstrated here with absolute impurity density radial profiles obtained in TEXTOR plasmas, using a high efficiency charge exchange spectrometer with high etendue, that measures the CXRS and BES spectra along the same lines-of-sight, offering an additional advantage for the determination of absolute impurity densities.

  20. Method to obtain absolute impurity density profiles combining charge exchange and beam emission spectroscopy without absolute intensity calibration

    Energy Technology Data Exchange (ETDEWEB)

    Kappatou, A.; Delabie, E. [FOM Institute DIFFER - Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, 3430 BE Nieuwegein (Netherlands); Jaspers, R. J. E.; Jakobs, M. A. [Science and Technology of Nuclear Fusion, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Marchuk, O.; Biel, W. [Institute for Energy and Climate Research, Forschungszentrum Julich GmbH, Trilateral Euregio Cluster, 52425 Julich (Germany)

    2012-10-15

    Investigation of impurity transport properties in tokamak plasmas is essential and a diagnostic that can provide information on the impurity content is required. Combining charge exchange recombination spectroscopy (CXRS) and beam emission spectroscopy (BES), absolute radial profiles of impurity densities can be obtained from the CXRS and BES intensities, electron density and CXRS and BES emission rates, without requiring any absolute calibration of the spectra. The technique is demonstrated here with absolute impurity density radial profiles obtained in TEXTOR plasmas, using a high efficiency charge exchange spectrometer with high etendue, that measures the CXRS and BES spectra along the same lines-of-sight, offering an additional advantage for the determination of absolute impurity densities.

  1. Spectroscopy

    CERN Document Server

    Walker, S

    1976-01-01

    The three volumes of Spectroscopy constitute the one comprehensive text available on the principles, practice and applications of spectroscopy. By giving full accounts of those spectroscopic techniques only recently introduced into student courses - such as Mössbauer spectroscopy and photoelectron spectroscopy - in addition to those techniques long recognised as being essential in chemistry teaching - sucha as e.s.r. and infrared spectroscopy - the book caters for the complete requirements of undergraduate students and at the same time provides a sound introduction to special topics for graduate students.

  2. Invited Article: The coherent optical laser beam recombination technique (COLBERT) spectrometer: Coherent multidimensional spectroscopy made easier

    Science.gov (United States)

    Turner, Daniel B.; Stone, Katherine W.; Gundogdu, Kenan; Nelson, Keith A.

    2011-08-01

    We have developed an efficient spectrometer capable of performing a wide variety of coherent multidimensional measurements at optical wavelengths. The two major components of the largely automated device are a spatial beam shaper which controls the beam geometry and a spatiotemporal pulse shaper which controls the temporal waveform of the femtosecond pulse in each beam. We describe how to construct, calibrate, and operate the device, and we discuss its limitations. We use the exciton states of a semiconductor nanostructure as a working example. A series of complex multidimensional spectra—displayed in amplitude and real parts—reveals increasingly intricate correlations among the excitons.

  3. Hyperfine structure and lifetime measurements in the 4s2nd 2D3/2 Rydberg sequence of Ga I by time-resolved laser spectroscopy

    Science.gov (United States)

    Liu, Chunqing; Tian, Yanshan; Yu, Qi; Bai, Wanshuang; Wang, Xinghao; Wang, Chong; Dai, Zhenwen

    2016-05-01

    The hyperfine structure (HFS) constants of the 4s2nd 2D3/2 (n=6-18) Rydberg sequence and the 4s26p 2P3/2 level for two isotopes of 69Ga and 71Ga atoms were measured by means of the time-resolved laser-induced fluorescence (TR-LIF) technique and the quantum beat method. The observed hyperfine quantum beat spectra were analyzed and the magnetic-dipole HFS constants A as well as the electric-quadrupole HFS constants B of these levels were obtained by Fourier transform and a program for multiple regression analysis. Also using TR-LIF method radiative lifetimes of the above sequence states were determined at room temperature. The measured lifetime values range from 69 to 2279 ns with uncertainties no more than 10%. To our knowledge, the HFS constants of this Rydberg sequence and the lifetimes of the 4s2nd 2D3/2 (n=10-18) levels are reported for the first time. Good agreement between our results and the previous is achieved.

  4. Effect of free-carrier concentration and optical injection on carrier lifetimes in undoped and iodine doped CdMgTe/CdSeTe double heterostructures grown by molecular beam epitaxy

    Science.gov (United States)

    Sohal, S.; Edirisooriya, M.; Ogedengbe, O. S.; Petersen, J. E.; Swartz, C. H.; LeBlanc, E. G.; Myers, T. H.; Li, J. V.; Holtz, M.

    2016-12-01

    Time-resolved and time integrated photoluminescence (PL) studies are reported for undoped and doped CdMgTe/CdSeTe double heterostructures (DHs) grown by molecular beam epitaxy. Undoped DHs are studied with absorber layer thickness varying from 0.5 to 2.5 µm. The n-type free-carrier concentration is varied ~7  ×  1015, 8.4  ×  1016, and 8.4  ×  1017 cm-3 using iodine as a dopant in different absorber layer thicknesses (0.25-2.0 µm). Optical injection is varied from 1  ×  1010 to 3  ×  1011 photons/pulse/cm2, corresponding to the initial injection of photo-carriers up to ~8  ×  1015 cm-3, to examine the effects of excess carrier concentration on the PL lifetimes. Undoped DHs exhibit an initial rapid decay followed by a slower dependence with carrier lifetimes up to ~485 ns. The dependence of carrier lifetimes on the thickness of the absorber layers (0.5-2.5 µm) suggests interface recombination velocities ({{v}\\operatorname{int}}~ ) ~ 1288 and 238 cm s-1 in the initial and later decay times, respectively, corresponding to high and low photo-carrier concentrations. The Shockley-Read-Hall model is used to describe the results in which variations are observed in {{v}\\operatorname{int}}~ for undoped DHs. The lifetimes of doped DHs show a consistent trend with thickness. The {{v}\\operatorname{int}}~ ~ 80-200 cm s-1 is estimated for doping n ~ 7  ×  1015 cm-3 and 240-410 cm s-1 for n ~ 8.4  ×  1016 cm-3. The observed decrease in carrier lifetimes with increasing n is consistent with growing importance of the radiative recombination rate due to the excess carrier concentration. The effect of carrier concentration on the PL spectrum is also discussed.

  5. Study of Nuclear Moments and Mean Square Charge Radii by Collinear Fast-Beam Laser Spectroscopy

    CERN Multimedia

    2002-01-01

    The collinear fast-beam laser technique is used to measure atomic hyperfine structures and isotope shifts of unstable nuclides produced at ISOLDE. This gives access to basic nuclear ground-state and isomeric-state properties such as spins, magnetic dipole and electric quadrupole moments, and the variation of the nuclear mean square charge radius within a sequence of isotopes. \\\\ \\\\ Among the various techniques used for this purpose, the present approach is of greatest versatility, due to the direct use of the beams from the isotope separator. Their phase-space properties are exploited to achieve high sensitivity and resolution. The optical spectra of neutral atoms are made accessible by converting the ion beams into fast atomic beams. This is accomplished in the charge-exchange cell which is kept at variable potential ($\\pm$10~kV) for Doppler-tuning of the effective laser wavelength. The basic optical resolution of 10$^{-8}$ requires a 10$^{-5}$ stability of the 60~kV main acceleration voltage and low energy ...

  6. Spectroscopy with trapped highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Beiersdorfer, P

    2008-01-23

    We give an overview of atomic spectroscopy performed on electron beam ion traps at various locations throughout the world. Spectroscopy at these facilities contributes to various areas of science and engineering, including but not limited to basic atomic physics, astrophysics, extreme ultraviolet lithography, and the development of density and temperature diagnostics of fusion plasmas. These contributions are accomplished by generating, for example, spectral surveys, making precise radiative lifetime measurements, accounting for radiative power emitted in a given wavelength band, illucidating isotopic effects, and testing collisional-radiative models. While spectroscopy with electron beam ion traps had originally focused on the x-ray emission from highly charged ions interacting with the electron beam, the operating modes of such devices have expanded to study radiation in almost all wavelength bands from the visible to the hard x-ray region; and at several facilities the ions can be studied even in the absence of an electron beam. Photon emission after charge exchange or laser excitation has been observed, and the work is no longer restricted to highly charged ions. Much of the experimental capabilities are unique to electron beam ion traps, and the work performed with these devices cannot be undertaken elsewhere. However, in other areas the work on electron beam ion traps rivals the spectroscopy performed with conventional ion traps or heavy-ion storage rings. The examples we present highlight many of the capabilities of the existing electron beam ion traps and their contributions to physics.

  7. Spectroscopy

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules.......This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules....

  8. In-beam gamma-ray spectroscopy of 35Mg and 33Na

    CERN Document Server

    Gade, A; Brown, B A; Campbell, C M; Cook, J M; Ettenauer, S; Glasmacher, T; Kemper, K W; McDaniel, S; Obertelli, A; Otsuka, T; Ratkiewicz, A; Terry, J R; Utsuno, Y; Weisshaar, D

    2011-01-01

    Excited states in the very neutron-rich nuclei 35Mg and 33Na were populated in the fragmentation of a 38Si projectile beam on a Be target at 83 MeV/u beam energy. We report on the first observation of gamma-ray transitions in 35Mg, the odd-N neighbor of 34Mg and 36Mg, which are known to be part of the "Island of Inversion" around N = 20. The results are discussed in the framework of large- scale shell-model calculations. For the A = 3Z nucleus 33Na, a new gamma-ray transition was observed that is suggested to complete the gamma-ray cascade 7/2+ --> 5/2+ --> 3/2+ gs connecting three neutron 2p-2h intruder states that are predicted to form a close-to-ideal K = 3/2 rotational band in the strong-coupling limit.

  9. Study on the effect of beam propagation through atmospheric turbulence on standoff nanosecond laser induced breakdown spectroscopy measurements.

    Science.gov (United States)

    Laserna, J J; Reyes, R Fernández; González, R; Tobaria, L; Lucena, P

    2009-06-08

    We report on an experimental study of the effect of atmospheric turbulence on laser induced breakdown spectroscopy (LIBS) measurements. The characteristics of the atmosphere dictate specific performance constraints to this technology. Unlike classical laboratory LIBS systems where the distance to the sample is well known and characterized, LIBS systems working at several tens of meters to the target have specific atmospheric propagation conditions that cause the quality of the LIBS signals to be affected to a significant extent. Using a new LIBS based sensor system fitted with a nanosecond laser emitting at 1064 nm, propagation effects at distances of up to 120 m were investigated. The effects observed include wander and scintillation in the outgoing laser beam and in the return atomic emission signal. Plasmas were formed on aluminium targets. Average signal levels and signal fluctuations are measured so the effect of atmospheric turbulence on LIBS measurements is quantified.

  10. Analysis of the fine structure of Sn$^{11+...14+}$ ions by optical spectroscopy in an electron beam ion trap

    CERN Document Server

    Windberger, A; Borschevsky, A; Ryabtsev, A; Dobrodey, S; Bekker, H; Eliav, E; Kaldor, U; Ubachs, W; Hoekstra, R; López-Urrutia, J R Crespo; Versolato, O O

    2016-01-01

    We experimentally re-evaluate the fine structure of Sn$^{11+...14+}$ ions. These ions are essential in bright extreme-ultraviolet (EUV) plasma-light sources for next-generation nanolithography, but their complex electronic structure is an open challenge for both theory and experiment. We combine optical spectroscopy of magnetic dipole $M1$ transitions, in a wavelength range covering 260\\,nm to 780\\,nm, with charge-state selective ionization in an electron beam ion trap. Our measurements confirm the predictive power of \\emph{ab initio} calculations based on Fock space coupled cluster theory. We validate our line identification using semi-empirical Cowan calculations with adjustable wavefunction parameters. Available Ritz combinations further strengthen our analysis. Comparison with previous work suggests that line identifications in the EUV need to be revisited.

  11. Automatic laser beam alignment using blob detection for an environment monitoring spectroscopy

    Science.gov (United States)

    Khidir, Jarjees; Chen, Youhua; Anderson, Gary

    2013-05-01

    This paper describes a fully automated system to align an infra-red laser beam with a small retro-reflector over a wide range of distances. The component development and test were especially used for an open-path spectrometer gas detection system. Using blob detection under OpenCV library, an automatic alignment algorithm was designed to achieve fast and accurate target detection in a complex background environment. Test results are presented to show that the proposed algorithm has been successfully applied to various target distances and environment conditions.

  12. Fast timing with plastic scintillators for in-beam heavy-ion spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hoischen, R., E-mail: robert.hoischen@nuclear.lu.se [Department of Physics, Lund University, SE-22100 Lund (Sweden); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Pietri, S. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Rudolph, D. [Department of Physics, Lund University, SE-22100 Lund (Sweden); Prokopowicz, W.; Schaffner, H. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Emde, S. [Lehrstuhl fuer Operations Management, Friedrich-Schiller-Universitaet Jena, D-07743 Jena (Germany); Golubev, P. [Department of Physics, Lund University, SE-22100 Lund (Sweden); Wendt, A. [Institut fuer Kernphysik, Universitaet zu Koeln, D-50937 Koeln (Germany); Kurz, N.; Wollersheim, H.J.; Gerl, J. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany)

    2011-10-21

    The design, R and D, and testing of a new plastic-scintillator detector for Time-of-Flight measurements with relativistic heavy-ion beams are presented. A design approach using 32 independent precise timing measurements of the same physical event is followed. This is different from the conventional scheme, which aims at two or four high-precision measurements. A circular, 27 cm in diameter, BC-420 plastic-scintillator sheet is read-out by 32 photomultiplier tubes in order to achieve an intrinsic detector resolution on the order of 10 ps root mean square.

  13. Study of argon additive in a beam injection type negative ion source using VUV emission spectroscopy

    OpenAIRE

    Nakada, Naoki; Fukumasa, Osamu

    2006-01-01

    Effects of Ar addition are studied by using a beam injection type negative ion source. With adding Ar, I_ increases at low base H_2 pressure. At high base H_2 pressure, however, I_ decreases. VUV emission intensities also decrease at high base pressure. In other words, Ar addition is adverse effect for production of H_2 (v''). Therefore, decrease in I_ is caused by decrease in H_2 (v''). In D_2 plasmas, variation patterns of plasma parameters and VUV intensities by Ar addition are nearly the ...

  14. Raman spectroscopy of individual monocytes reveals that single-beam optical trapping of mononuclear cells occurs by their nucleus

    Science.gov (United States)

    Fore, Samantha; Chan, James; Taylor, Douglas; Huser, Thomas

    2011-01-01

    We show that laser-tweezers Raman spectroscopy of eukaryotic cells with a significantly larger diameter than the tight focus of a single beam laser trap leads to optical trapping of the cell by its optically densest part, i.e. typically the cell’s nucleus. Raman spectra of individual optically trapped monocytes are compared with location-specific Raman spectra of monocytes adhered to a substrate. When the cell’s nucleus is stained with a fluorescent live cell stain, the Raman spectrum of the DNA-specific stain is observed only in the nucleus of individual monocytes. Optically trapped monocytes display the same behavior. We also show that the Raman spectra of individual monocytes exhibit the characteristic Raman signature of cells that have not yet fully differentiated and that individual primary monocytes can be distinguished from transformed monocytes based on their Raman spectra. This work provides further evidence that laser tweezers Raman spectroscopy of individual cells provides meaningful biochemical information in an entirely nondestructive fashion that permits discerning differences between cell types and cellular activity. PMID:21984959

  15. Spectroscopy of high lying resonances in {sup 9}Be produced with radioactive {sup 8}Li beams

    Energy Technology Data Exchange (ETDEWEB)

    Lepini-Szily, A.; Leistenschneider, E.; Lichtenthäler, R.; Guimaraes, V.; Condori, R. Pampa; Scarduelli, V.; Rossi, E.; Zagatto, V.A.; Aguiar, V.A.P.; Duarte, J., E-mail: alinka@if.usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica; Mendes Junior, D.R.; Faria, P.N. de; Santos, H. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Instituto de Fisica; Descouvemont, P. [Physique Nucleaire Theorique et Physique Mathematique, Universite Libre de Bruxelles (ULB), Brussels (Belgium); Barioni, A. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil); Pires, K.C.C. [Universidade Tecnologica Federal do Parana (UFTPR), Cornelio Procopio, PR (Brazil); Morcelle, V. [Universidade Federal de Itajuba (UNIFEI), Itabira, MG (Brazil); Moraes, M.C. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Britos, T.; Assuncao, M. [Universidade Federal de Sao Paulo (UNIFESP), Diadema, SP (Brazil); Zamora, J.C. [Technische Universität Darmstadt, (Germany); Shorto, J.M.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2014-07-01

    We present the results of the {sup 8}Li(p,α){sup 5}He and {sup 8}Li(p,p){sup 8}Li reactions measured at the RIBRAS (Radioactive Ion Beams in Brazil) system. The experiment was realized in inverse kinematics using a thick [CH{sub 2}]{sub n} polyethylene target and an incident {sup 8}Li beam, produced by RIBRAS. Using the thick target method, the complete excitation function could be measured between E{sub cm} = 0.2 - 2.1 MeV, which includes the Gamow peak energy region. The excitation function of the {sup 8}Li(p,α){sup 5}He reaction, populating resonances between 16.888 and 19.0 MeV in {sup 9}Be, was obtained[1] and the resonances were fitted using R-matrix calculations. This study shed light on spins, parities, partial widths and isospin values of high lying resonances in {sup 9}Be. The measurement of the resonant elastic scattering {sup 8}Li(p,p){sup 8}Li populating resonances in the same energy region can constrain the resonance parameters. Preliminary results of the elastic scattering are also presented. (author)

  16. Characterizing a multi-MeV e-beam induced plasma through visible spectroscopy and imaging

    Science.gov (United States)

    D'Almeida, Thierry; Ribiere, Maxime; Maisonny, Rémi; Ritter, Sandra; Plouhinec, Damien; Auriel, Gérard

    2016-10-01

    High energy electrons interaction and propagation mechanisms in solid targets have a broad range of applications in high energy density physics. The latter include fast ignition for inertial fusion research, production of ultra-high mechanical stress levels, plasma interactions with e-beam particles in electron diodes, radiative hydrodynamic models...This paper presents the results from recent experiments conducted on the multi-MeV generator ASTERIX operated at CEA-Gramat. This high flux density electron beam was launched from an aluminum cathode onto an aluminum-tantalum target for voltage and current of 2.4 MeV and 55 kA, respectively. A set of optical diagnostics were fielded in all of the experiments, including a UV-visible spectrometers and a fast imaging. The imaging data obtained during the experiment allowed for the ablated species velocity to be determined. based on spectroscopic analysis, the light emission was attributed to aluminum and tantalum excited atoms and ions. The analysis of this time-integrated spectrum based on radiative transfer model clearly unveiled two distinct regions of the plasma over its expansion: a hot core surrounded by a cold vapor. A quantitative analysis of these results is presented.

  17. Nuclear Instruments and Methods in Physics Research. Section B; Microstructural Characterization of Semi-Interpenetrating Polymer Networks by Positron Lifetime Spectroscopy

    Science.gov (United States)

    Singh, Jag J.; Pater, Ruth H.; Eftekhari, Abe

    1998-01-01

    Thermoset and thermoplastic polyimides have complementary physical/mechanical properties. Whereas thermoset polyimides are brittle and generally easier to process, thermoplastic polyimides are tough but harder to process. It is expected that a combination of these two types of polyimides may help produce polymers more suitable for aerospace applications. Semi-Interpenetrating Polymer Networks (S-IPNs) of thermoset LaRC(Trademark)-RP46 and thermoplastic LARC(Trademark)-IA polyimides were prepared in weight percent ratios ranging from 100:0 to 0: 100. Positron lifetime measurements were made in these samples to correlate their free volume features with physical/mechanical properties. As expected, positronium atoms are not formed in these samples. The second life time component has been used to infer the positron trap dimensions. The "free volume" goes through a minimum at about 50:50 ratio, suggesting that S-IPN samples are not merely solid solutions of the two polymers. These data and related structural properties of the S-IPN samples have been discussed in this paper.

  18. Different emissive states in the bulk and at the surface of methylammonium lead bromide perovskite revealed by two-photon micro-spectroscopy and lifetime measurements

    Directory of Open Access Journals (Sweden)

    Khadga Jung Karki

    2016-07-01

    Full Text Available Two photon photoluminescence (2PPL from single crystals of methyl ammonium lead bromide (CH3NH3PbBr3, MAPbBr3 is studied. We observe two components in the 2PPL spectra, which we assign to the photoluminescence (PL from the carrier recombination at the band edge and the recombination due to self-trapping of excitons. The PL Stokes shift of self-trapped excitons is about 100 meV from the band-gap energy. Our measurements show that about 15% of the total PL from regions about 40 μm deep inside the crystal is due to the emission from self-trapped exciton. This contribution increases to about 20% in the PL from the regions close to the surface. Time resolved measurements of 2PPL show that the PL due to band-edge recombination has a life time of about 8 ns while the PL lifetime of self-trapped excitons is in the order of 100 ns. Quantification of self-trapped excitons in the materials used in photovoltaics is important as such excitons hinder charge separation. As our results also show that an appreciable fraction of photo-generated carriers get trapped, the results are important in rational design of photovoltaics. On the other hand, our results also show that the self-trapped excitons broaden the emission spectrum, which may be useful in designing broadband light emitting devices.

  19. Provenance studies of Central European Neolithic obsidians using external beam milli-PIXE spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Constantinescu, B.; Cristea-Stan, D. [National Institute for Nuclear Physics and Engineering “Horia Hulubei”, Str. Reactorului No.3, Bucharest-Magurele (Romania); Kovács, I. [Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Konkoly-Thege Miklós út 29-33, H-1121 Budapest (Hungary); Szőkefalvi-Nagy, Z., E-mail: szokefalvi-nagy@wigner.mta.hu [Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Konkoly-Thege Miklós út 29-33, H-1121 Budapest (Hungary)

    2014-01-01

    External beam milli-PIXE technique was used for the determination of the elemental concentration ratios in some Prehistoric obsidian tools found in Transylvania, in the Iron Gates region near Danube, as well as on a few relevant geological obsidian samples from Slovak Tokaj Mountains, Lipari, Armenia. As provenance “fingerprints” the Ti to Mn and Rb to Zr ratios were used. The results confirm that the Transylvanian Neolithic samples have a Slovak Tokaj Mountains provenance. For Iron Gates samples, there are at least two different geological sources: for Late Neolithic tools, the origin is also the Slovak Tokaj Mountains but for Late Mesolithic–Early Neolithic samples, the sources are clearly different, possibly of the Hungarian Tokaj Mountains or the Balkan–Aegean origin.

  20. High-resolution electronic spectroscopy of the BODIPY chromophore in supersonic beam and superfluid helium droplets.

    Science.gov (United States)

    Stromeck-Faderl, Anja; Pentlehner, Dominik; Kensy, Uwe; Dick, Bernhard

    2011-07-11

    We present the fluorescence excitation and dispersed emission spectra of the parent compound of the boron dipyrromethene (BODIPY) dye class measured in a supersonic beam and isolated in superfluid helium nanodroplets. The gas-phase spectrum of the isolated molecules displays many low-frequency transitions that are assigned to a symmetry-breaking mode with a strongly nonharmonic potential, presumably the out-of-plane wagging mode of the BF(2) group. The data are in good agreement with transition energies and Franck-Condon factors calculated for a double minimum potential in the upper electronic state. The corresponding transitions do not appear in the helium droplet. This is explained with the quasi-rigid first layer of helium atoms attached to the dopant molecule by van der Waals forces. The spectral characteristics are those of a cyanine dye rather than that of an aromatic chromophore. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. CZT strip detectors for imaging and spectroscopy: Collimated beam and ASIC readout experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kurczynski, P. [Univ. of Maryland, College Park, MD (United States); Krizmanic, J.F.; Parsons, A. [Goddard Space Flight Center, Greenbelt, MD (United States)

    1996-12-31

    We report the status of ongoing investigations into Cadmium Zinc Telluride (CZT) strip detectors for application in hard x-ray astronomy. We have instrumented a nine strip by nine strip region of a two sided strip detector made in our detector fabrication facility. In order to measure the position resolution of our detectors, we have implemented a collimated beam that concentrates radiation to a spot size less than the strip width of our detector. We have also performed charge collection studies as a function of incident photon energy and bias voltage with a single sided, 100{mu}m pitch CZT strip detector wire bonded to an SVX ASIC charge amplifier. The detectors exhibited excellent strip uniformity in terms of photon count rate and spectroscopic information.

  2. Spectroscopy of neutron-rich hypernucleus, $^{7}_{\\Lambda}$He by electron beam

    CERN Document Server

    Gogami, T; Kawama, D; Achenbach, P; Ahmidouch, A; Albayrak, I; Androic, D; Asaturyan, A; Asaturyan, R; Ates, O; Baturin, P; Badui, R; Boeglin, W; Bono, J; Brash, E; Carter, P; Chiba, A; Christy, E; Danagoulian, S; De Leo, R; Doi, D; Elaasar, M; Ent, R; Fujii, Y; Fujita, M; Furic, M; Gabrielyan, M; Gan, L; Garibaldi, F; Gaskell, D; Gasparian, A; Han, Y; Hashimoto, O; Horn, T; Hu, B; Hungerford, Ed V; Jones, M; Kanda, H; Kaneta, M; Kato, S; Kawai, M; Khanal, H; Kohl, M; Liyanage, A; Luo, W; Maeda, K; Margaryan, A; Markowitz, P; Maruta, T; Matsumura, A; Maxwell, V; Mkrtchyan, A; Mkrtchyan, H; Nagao, S; Nakamura, S N; Narayan, A; Neville, C; Niculescu, G; Niculescu, M I; Nunez, A; Nuruzzaman,; Okayasu, Y; Petkovic, T; Pochodzalla, J; Qiu, X; Reinhold, J; Rodriguez, V M; Samanta, C; Sawatzky, B; Seva, T; Shichijo, A; Tadevosyan, V; Tang, L; Taniya, N; Tsukada, K; Veilleux, M; Vulcan, W; Wesselmann, F R; Wood, S A; Yamamoto, T; Ya, L; Ye, Z; Yokota, K; Yuan, L; Zhamkochyan, S; Zhu, L

    2016-01-01

    The missing mass spectroscopy of the $^{7}_{\\Lambda}$He hypernucleus was performed, using the $^{7}$Li$(e,e^{\\prime}K^{+})^{7}_{\\Lambda}$He reaction at JLab Hall-C. The $\\Lambda$ binding energy of the ground state (1/2$^{+}$) was determined with a smaller error than that of the previous measurement, being $B_{\\Lambda}$ = 5.55 $\\pm$ 0.10(stat.) $\\pm$ 0.11(sys.) MeV. The experiment also provided new insight into charge symmetry breaking in p-shell hypernuclear systems. Finally, a peak at $B_{\\Lambda}$ = 3.65 $\\pm$ 0.20(stat.) $\\pm$ 0.11(sys.) MeV was observed and assigned as a mixture of 3/2$^{+}$ and 5/2$^{+}$ states, confirming the "glue-like" behavior of $\\Lambda$, which makes an unstable state in $^{6}$He stable against neutron emission.

  3. High resolution photoelectron spectroscopy and femtosecond intramolecular dynamics using supersonic molecular beams

    Energy Technology Data Exchange (ETDEWEB)

    Niu, B.

    1992-09-01

    High resolution He I[alpha] photoelectron spectroscopy of formaldehyde and ketene and their deuterated compounds, are reported. The combination of a (H2CO) double-pass high-resolution electron-energy analyzer and effective rotational cooling of the sample by supersonic expansion enable the spectroscopy of these molecular cations. The vibrational autocorrelation functions are calculated from the high-resolution photoelectron spectra, shedding light on the ultrafast intramolecular dynamics of the molecular cations. This study reveals much more vibrational structural detail in the first electronic excited state of H2CO cations. The first electronic excited state of H2CO cations may have nonplanar equilibrium geometry. Strong isotope effects on vibronic (vibrational) coupling are observed in the second electronic excited state of H2CO. Vibrational autocorrelation functions are calculated for all four observed electronic states of H2CO. The correlation function of the first electronic excited state of H2CO shows a slow decay rate on the femtosecond time scale. The ultrafast decay of the H2CO cations in the third electronic excited state implies that dissociation and intramolecular processes are the main decay pathways. The present spectra of the ground states of ketene cations have more fine structure than before. The AIEs of the first and fifth excited states are determined unambiguously more accurately. The doublet-like fine structures present in the lint excited state of ketene implies the excitation of a soft'' mode not observed before. The vibrational autocorrelation functions are calculated for 4 of the 6 observed electronic states. The dynamics of the ground states of the cations are characterized by a wave packet oscillating with small amplitude around the minimum on the upper PES. The decay dynamics of the first and the fifth excited states of ketene are characterized by ultra-fast intramolecular processes like predissociation.

  4. High resolution photoelectron spectroscopy and femtosecond intramolecular dynamics using supersonic molecular beams

    Energy Technology Data Exchange (ETDEWEB)

    Niu, B.

    1992-09-01

    High resolution He I{alpha} photoelectron spectroscopy of formaldehyde and ketene and their deuterated compounds, are reported. The combination of a (H2CO) double-pass high-resolution electron-energy analyzer and effective rotational cooling of the sample by supersonic expansion enable the spectroscopy of these molecular cations. The vibrational autocorrelation functions are calculated from the high-resolution photoelectron spectra, shedding light on the ultrafast intramolecular dynamics of the molecular cations. This study reveals much more vibrational structural detail in the first electronic excited state of H2CO cations. The first electronic excited state of H2CO cations may have nonplanar equilibrium geometry. Strong isotope effects on vibronic (vibrational) coupling are observed in the second electronic excited state of H2CO. Vibrational autocorrelation functions are calculated for all four observed electronic states of H2CO. The correlation function of the first electronic excited state of H2CO shows a slow decay rate on the femtosecond time scale. The ultrafast decay of the H2CO cations in the third electronic excited state implies that dissociation and intramolecular processes are the main decay pathways. The present spectra of the ground states of ketene cations have more fine structure than before. The AIEs of the first and fifth excited states are determined unambiguously more accurately. The doublet-like fine structures present in the lint excited state of ketene implies the excitation of a ``soft`` mode not observed before. The vibrational autocorrelation functions are calculated for 4 of the 6 observed electronic states. The dynamics of the ground states of the cations are characterized by a wave packet oscillating with small amplitude around the minimum on the upper PES. The decay dynamics of the first and the fifth excited states of ketene are characterized by ultra-fast intramolecular processes like predissociation.

  5. The development of soviet optics and spectroscopy during the past fifty years.

    Science.gov (United States)

    Frish, S

    1967-11-01

    A history of Soviet spectroscopy is given, with special emphasis on various areas indicating the earliest workers in each specialty and their principal successors; for example, the work of Rozhdestvenskii (anomalous dispersion); Fok (self-consistant field calculations), Terenin (photochemistry, atomic beams), Mandelstam (combination scattering), Vavilov (luminescence, quantum properties of light), Cerenkov (radiation), Chaika (atomic lifetimes), Gross (excitons), and Volkenstein (molecular vibrations).

  6. Electric and Magnetic Field Measurements in High Energy Electron Beam Diode Plasmas using Optical Spectroscopy

    Science.gov (United States)

    Johnston, Mark; Patel, Sonal; Kiefer, Mark; Biswas, S.; Doron, R.; Stambulchik, E.; Bernshtam, V.; Maron, Yitzhak

    2016-10-01

    The RITS accelerator (5-11MV, 100-200kA) at Sandia National Laboratories is being used to evaluate the Self-Magnetic Pinch (SMP) diode as a potential flash x-ray radiography source. This diode consists of a small, hollowed metal cathode and a planar, high atomic mass anode, with a small vacuum gap of approximately one centimeter. The electron beam is focused, due to its self-field, to a few millimeters at the target, generating bremsstrahlung x-rays. During this process, plasmas form on the electrode surfaces and propagate into the vacuum gap, with a velocity of a 1-10 cm's/microseconds. These plasmas are measured spectroscopically using a Czerny-Turner spectrometer with a gated, ICCD detector, and input optical fiber array. Local magnetic and electric fields of several Tesla and several MV/cm were measured through Zeeman splitting and Stark shifting of spectral lines. Specific transitions susceptible to quantum magnetic and electric field effects were utilized through the application of dopants. Data was analyzed using detailed, time-dependent, collisional-radiative (CR) and radiation transport modeling. Recent results will be presented. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  7. Tin re-deposition and erosion measured by cavity-ring-down-spectroscopy under a high flux plasma beam

    Science.gov (United States)

    Kvon, V.; Al, R.; Bystrov, K.; Peeters, F. J. J.; van de Sanden, M. C. M.; Morgan, T. W.

    2017-08-01

    Cavity-ring-down spectroscopy (CRDS) was implemented to measure the re-deposition of liquid tin under a high flux plasma beam in the linear plasma device Pilot-PSI. A capillary porous system (CPS) consisting of a molybdenum cup and tungsten meshes (pores diameters of 0.2 mm and 0.44 mm) was filled with tin and exposed to argon plasma. The absorption of a UV laser-beam at 286.331 nm was used to determine a number of sputtered neutral tin atoms. The incoming flux of argon ions of ~50 eV was 1.6-2.7  ×  1023 m-2 s-1, and the sample temperature measured by pyrometry varied from 850 °C to 1200 °C during exposures. The use of CRDS for measuring absolute number of particles under such plasma exposure was demonstrated for the first time. The number of sputtered tin particles in the cavity region assuming no losses would be expected to be 5.5  ×  1011-1.2  ×  1012 while CRDS measurements showed only 5.7-9.9  ×  108. About 98-99.8% of sputtered particles were therefore found to not reach the CRDS observation volume. Spectroscopic ratios of Sn I to Sn II ions, as well as equilibrium considerations, indicate that fast ionization as well as plasma entrainment of neutrals is responsible for the discrepancy. This would lead to high re-deposition rates, implying a lowered contamination rate of core plasma and lower required replenishment rates at high-flux conditions than would otherwise be expected.

  8. The ROSPHERE γ-ray spectroscopy array

    Science.gov (United States)

    Bucurescu, D.; Căta-Danil, I.; Ciocan, G.; Costache, C.; Deleanu, D.; Dima, R.; Filipescu, D.; Florea, N.; Ghiţă, D. G.; Glodariu, T.; Ivaşcu, M.; Lică, R.; Mărginean, N.; Mărginean, R.; Mihai, C.; Negret, A.; Niţă, C. R.; Olăcel, A.; Pascu, S.; Sava, T.; Stroe, L.; Şerban, A.; Şuvăilă, R.; Toma, S.; Zamfir, N. V.; Căta-Danil, G.; Gheorghe, I.; Mitu, I. O.; Suliman, G.; Ur, C. A.; Braunroth, T.; Dewald, A.; Fransen, C.; Bruce, A. M.; Podolyák, Zs.; Regan, P. H.; Roberts, O. J.

    2016-11-01

    The ROmanian array for SPectroscopy in HEavy ion REactions (ROSPHERE) has been designed as a multi-detector setup dedicated to γ-ray spectroscopy studies at the Bucharest 9 MV Tandem accelerator. Consisting of up to 25 detectors (either Compton suppressed HPGe detectors or fast LaBr3(Ce) scintillator detectors) together with a state of the art plunger device, ROSPHERE is a powerful tool for lifetime measurements using the Recoil Distance Doppler Shift (RDDS) and the in-beam Fast Electronic Scintillation Timing (FEST) methods. The array's geometry, detectors, electronics and data acquisition system are described. Selected results from the first experimental campaigns are also presented.

  9. Photodissociation dynamics of the methyl perthiyl radical at 248 and 193 nm using fast-beam photofragment translational spectroscopy

    Science.gov (United States)

    Harrison, Aaron W.; Ryazanov, Mikhail; Sullivan, Erin N.; Neumark, Daniel M.

    2016-07-01

    The photodissociation dynamics of the methyl perthiyl radical (CH3SS) have been investigated using fast-beam coincidence translational spectroscopy. Methyl perthiyl radicals were produced by photodetachment of the CH3SS- anion followed by photodissociation at 248 nm (5.0 eV) and 193 nm (6.4 eV). Photofragment mass distributions and translational energy distributions were measured at each dissociation wavelength. Experimental results show S atom loss as the dominant (96%) dissociation channel at 248 nm with a near parallel, anisotropic angular distribution and translational energy peaking near the maximal energy available to ground state CH3S and S fragments, indicating that the dissociation occurs along a repulsive excited state. At 193 nm, S atom loss remains the major fragmentation channel, although S2 loss becomes more competitive and constitutes 32% of the fragmentation. The translational energy distributions for both channels are very broad at this wavelength, suggesting the formation of the S2 and S atom products in several excited electronic states.

  10. Impedance spectroscopy characterization of GaAs nanowire bundles grown by metal-catalyzed molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Tirado, M., E-mail: mtirado@herrera.unt.edu.a [Laboratorio de Propiedades Dielectricas de la Materia, Dep. Fisica, FACET, Universidad Nacional de Tucuman, Avda. Independencia 1800, 4000 Tucuman (Argentina); Comedi, D. [Laboratorio de Fisica del Solido, Dep. Fisica, FACET, Universidad Nacional de Tucuman, Avda. Independencia 1800, 4000 Tucuman (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); LaPierre, R.R. [Dep. Eng. Physics, McMaster University, 1280 Main W, Hamilton L8S 4L7, ON (Canada)

    2010-04-16

    Vertically aligned GaAs nanowire (NW) bundles grown by gas-source molecular beam epitaxy on an n-doped GaAs substrate by a metal catalysis method and embedded in an insulating matrix (SU8-2) were studied by impedance spectroscopy. The DC current-voltage characteristics measured between Au dot contacts to the NW tips and the substrate exhibited Schottky behavior. A detailed analysis of the impedance data measured in reverse bias conditions is presented, which enables the elimination of the stray capacitance due to the insulating matrix, and the separation of the different contributions to the total admittance from the metal/NW Schottky interface and from the NW region beyond the barrier region. The observed NW conductances and capacitances are shown to be consistent with rough estimates based on the GaAs conductivity and permittivity data and the NW dimensions, and the NW conductance increases as a power law of the frequency. Possible charge transport mechanisms to explain this result are discussed.

  11. Measuring one-dimensional and two-dimensional impurity density profiles on TEXTOR using combined charge exchange-beam emission spectroscopy and ultrasoft x-ray tomography

    Science.gov (United States)

    De Bock, M.; Jakubowska, K.; Hellermann, M. von; Jaspers, R.; Donné, A. J. H.; Shmaenok, L.

    2004-10-01

    Two techniques are presented that allow us to measure impurity density profiles in the TEXTOR tokamak plasma. The one-dimensional profiles are gathered by charge exchange recombination spectroscopy (CXRS) in combination with beam emission spectroscopy (BES). Combining CXRS and BES eliminate the need for absolute calibration. For two-dimensional profiles an ultrasoft x-ray tomography system has been developed. The system is spectrally resolved and produces local emissivity profiles of several ionization stages of impurities. Both systems are presently being commissioned. They are complementary and give an insight into the impurity distribution and transport in plasmas.

  12. The performance of the γ-ray tracking array GRETINA for γ-ray spectroscopy with fast beams of rare isotopes

    Science.gov (United States)

    Weisshaar, D.; Bazin, D.; Bender, P. C.; Campbell, C. M.; Recchia, F.; Bader, V.; Baugher, T.; Belarge, J.; Carpenter, M. P.; Crawford, H. L.; Cromaz, M.; Elman, B.; Fallon, P.; Forney, A.; Gade, A.; Harker, J.; Kobayashi, N.; Langer, C.; Lauritsen, T.; Lee, I. Y.; Lemasson, A.; Longfellow, B.; Lunderberg, E.; Macchiavelli, A. O.; Miki, K.; Momiyama, S.; Noji, S.; Radford, D. C.; Scott, M.; Sethi, J.; Stroberg, S. R.; Sullivan, C.; Titus, R.; Wiens, A.; Williams, S.; Wimmer, K.; Zhu, S.

    2017-03-01

    The γ-ray tracking array GRETINA was coupled to the S800 magnetic spectrometer for spectroscopy with fast beams of rare isotopes at the National Superconducting Cyclotron Laboratory on the campus of Michigan State University. We describe the technical details of this powerful setup and report on GRETINA's performance achieved with source and in-beam measurements. The γ-ray multiplicity encountered in experiments with fast beams is usually low, allowing for a simplified and efficient treatment of the data in the γ-ray analysis in terms of Doppler reconstruction and spectral quality. The results reported in this work were obtained from GRETINA consisting of 8 detector modules hosting four high-purity germanium crystals each. Currently, GRETINA consists of 10 detector modules.

  13. Determination of the Free Neutron Lifetime

    CERN Document Server

    Bowman, J David; Clayton, S M; Dewey, M S; Fomin, N; Grammer, K B; Greene, G L; Huffman, P R; Holley, A T; Jones, G L; Liu, C -Y; Makela, M; Mendenhall, M P; Morris, C L; Mulholland, J; Nollett, K M; Pattie,, R W; Penttila, S; Ramsey-Musolf, M; Salvat, D J; Saunders, A; Seestrom, S J; Snow, W M; Steyerl, A; Wietfeldt, F E; Young, A R; Yue, A T

    2014-01-01

    We present the status of current US experimental efforts to measure the lifetime of the free neutron by the "beam" and "bottle" methods. BBN nucleosynthesis models require accurate measurements with 1 second uncertainties, which are currently feasible. For tests of physics beyond the standard model, future efforts will need to achieve uncertainties well below 1 second. We outline paths achieve both.

  14. Time-resolved microspectrofluorometry and fluorescence lifetime imaging of photosensitizers using picosecond pulsed diode lasers in laser scanning microscopes.

    Science.gov (United States)

    Kress, Matthias; Meier, Thomas; Steiner, Rudolf; Dolp, Frank; Erdmann, Rainer; Ortmann, Uwe; Rück, Angelika

    2003-01-01

    This work describes the time-resolved fluorescence characteristics of two different photosensitizers in single cells, in detail mTHPC and 5-ALA induced PPIX, which are currently clinically used in photodynamic therapy. The fluorescence lifetime of the drugs was determined in the cells from time-gated spectra as well as single photon counting, using a picosecond pulsed diode laser for fluorescence excitation. The diode laser, which emits pulses at 398 nm with 70 ps full width at half maximum duration, was coupled to a confocal laser scanning microscope. For time-resolved spectroscopy a setup consisting of a Czerny Turner spectrometer and a MCP-gated and -intensified CCD camera was used. Time-gated spectra within the cells were acquired by placing the laser beam in "spot scan" mode. In addition, a time-correlated single photon counting module was used to determine the fluorescence lifetime from single spots and to record lifetime images. The fluorescence lifetime of mTHPC decreased from 7.5 to 5.5 ns during incubation from 1 to 6 h. This decrease was probably attributed to enhanced formation of aggregates during incubation. Fluorescence lifetime imaging showed that longer lifetimes were correlated with accumulation in the cytoplasm in the neighborhood of the cell nucleus, whereas shorter lifetimes were found in the outer cytoplasm. For cells that were incubated with 5-ALA, a fluorescence lifetime of 7.4 ns was found for PPIX; a shorter lifetime at 3.6 ns was probably attributed to photoproducts and aggregates of PPIX. In contrast from fluorescence intensity images alone, different fluorescence species could not be distinguished. However, in the lifetime image a structured fluorescence distribution in the cytoplasm was correlated with the longer lifetime and probably coincides with mitochondria. In conclusion, picosecond diode lasers coupled to a laser scanning microscope equipped with appropriate detection units allows time-resolved spectroscopy and lifetime imaging

  15. Beam-beam effects in the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, V.; Alexahin, Y.; Lebedev, V.; Lebrun, P.; Moore, R.S.; Sen, T.; Tollestrup, A.; Valishev, A.; Zhang, X.L.; /Fermilab

    2005-01-01

    The Tevatron in Collider Run II (2001-present) is operating with 6 times more bunches, many times higher beam intensities and luminosities than in Run I (1992-1995). Electromagnetic long-range and head-on interactions of high intensity proton and antiproton beams have been significant sources of beam loss and lifetime limitations. We present observations of the beam-beam phenomena in the Tevatron and results of relevant beam studies. We analyze the data and various methods employed in operations, predict the performance for planned luminosity upgrades, and discuss ways to improve it.

  16. Computing Battery Lifetime Distributions

    NARCIS (Netherlands)

    Cloth, L.; Haverkort, Boudewijn R.H.M.; Jongerden, M.R.

    The usage of mobile devices like cell phones, navigation systems, or laptop computers, is limited by the lifetime of the included batteries. This lifetime depends naturally on the rate at which energy is consumed, however, it also depends on the usage pattern of the battery. Continuous drawing of a

  17. Computing Battery Lifetime Distributions

    NARCIS (Netherlands)

    Cloth, Lucia; Jongerden, Marijn R.; Haverkort, Boudewijn R.

    2007-01-01

    The usage of mobile devices like cell phones, navigation systems, or laptop computers, is limited by the lifetime of the included batteries. This lifetime depends naturally on the rate at which energy is consumed, however, it also depends on the usage pattern of the battery. Continuous drawing of a

  18. Measurement of the scalar polarizability of the indium $6p_{1/2}$ state using two-step atomic-beam spectroscopy

    CERN Document Server

    Augenbraun, Benjamin L; Rupasinghe, P M; Majumder, P K

    2016-01-01

    We have completed a measurement of the Stark shift within the $^{115}$In $6s_{1/2} \\rightarrow 6p_{1/2}$ excited-state transition using two-step laser spectroscopy in an indium atomic beam. Combining this measurement with recent experimental results we determine the scalar polarizability, $\\alpha_{0}$, of the $6p_{1/2}$ state to be $7683 \\pm43 \\,a_{0}^{3}$ in atomic units, a result which agrees very well with recent theoretical calculations. In this experiment, one laser, stabilized to the $5p_{1/2} \\rightarrow 6s_{1/2}$ 410~nm transition, was directed transversely to the atomic beam, while a second, overlapping laser was scanned across the 1343~nm $6s_{1/2} \\rightarrow 6p_{1/2}$ transition. We utilized two-tone frequency-modulation spectroscopy of the infrared laser beam to measure the second-step absorption in the interaction region, where the optical depth is less than 10$^{-3}$. In the course of our experimental work we also determined the hyperfine splitting within the $6p_{1/2}$ state, improving upon th...

  19. OH concentration in an atmospheric-pressure methane-air flame from molecular-beam mass spectrometry and laser-absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cattolica, R.J.; Yoon, S.; Knuth, E.L.

    1980-12-01

    The concentration of the OH radical in a stoichiometric methane-air flat flame at atmospheric pressure was measured with both laser-absorption spectroscopy and molecular-beam mass spectrometry (MBMS). The nonequilibrium peak OH concentrations and the OH decay rate measured from the two techniques were in good agreement. The OH profile from the MBMS measurements, however, was shifted downstream from the absorption measurements by approximately 5 times the sampling-orifice diameter. A comparison of temperature profiles from thermocouple measurements and from a molecular-beam time-of-flight technique exhibited a similar downstream shift. The MBMS measurements effectively sampled the gas properties approximately five orifice diameters ahead of the sampling-probe tip. Perturbation of the OH concentration profile using various sampling probes indicate the importance of minimizing the length of the sampling-orifice channel to reduce composition relaxation during sampling.

  20. Watching adsorption and electron beam induced decomposition on the model system Mo(CO){sub 6}/Cu(1 1 1) by X-ray absorption and photoemission spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Paufert, Pierre, E-mail: pierre.paufert@u-bourgogne.fr [ICB, UMR 6303 CNRS-Université de Bourgogne, BP 47870, 21078 Dijon cedex (France); Fonda, Emiliano [Synchrotron SOLEIL, BP48, St Aubin, 91192 Gif sur Yvette cedex (France); Li, Zheshen [ISA, University of Aarhus, Ny Munkegade, DK-8000 Aarhus C (Denmark); Domenichini, Bruno, E-mail: bruno.domenichini@u-bourgogne.fr [ICB, UMR 6303 CNRS-Université de Bourgogne, BP 47870, 21078 Dijon cedex (France); Bourgeois, Sylvie [ICB, UMR 6303 CNRS-Université de Bourgogne, BP 47870, 21078 Dijon cedex (France)

    2013-11-01

    An in-depth study of the first steps of electron beam assisted growth of Mo from molybdenum hexacarbonyl on Cu(1 1 1) has been carried out exploiting the complementarity of X-ray photoemission and X-ray absorption spectroscopies. Frank van der Merwe (2D) growth mode has been observed for the completion of the two first monolayers of adsorbed molecules through a simple physisorption process. Irradiation of the Mo(CO){sub 6} deposit by 1 keV electron beam induces a modification of molybdenum coordination, the average number of C-neighbors decreasing from 6 to 3. Decomposed molecules remain on the surface after annealing at 520 K and organize themselves, the molybdenum atoms moving in Cu(1 1 1) surface fcc hollow sites. After annealing at 670 K, metallic molybdenum growth begins, if the total amount of adsorbed Mo atoms exceeds 1.2 monolayers.

  1. Watching adsorption and electron beam induced decomposition on the model system Mo(CO)6/Cu(1 1 1) by X-ray absorption and photoemission spectroscopies

    Science.gov (United States)

    Paufert, Pierre; Fonda, Emiliano; Li, Zheshen; Domenichini, Bruno; Bourgeois, Sylvie

    2013-11-01

    An in-depth study of the first steps of electron beam assisted growth of Mo from molybdenum hexacarbonyl on Cu(1 1 1) has been carried out exploiting the complementarity of X-ray photoemission and X-ray absorption spectroscopies. Frank van der Merwe (2D) growth mode has been observed for the completion of the two first monolayers of adsorbed molecules through a simple physisorption process. Irradiation of the Mo(CO)6 deposit by 1 keV electron beam induces a modification of molybdenum coordination, the average number of C-neighbors decreasing from 6 to 3. Decomposed molecules remain on the surface after annealing at 520 K and organize themselves, the molybdenum atoms moving in Cu(1 1 1) surface fcc hollow sites. After annealing at 670 K, metallic molybdenum growth begins, if the total amount of adsorbed Mo atoms exceeds 1.2 monolayers.

  2. Lifetime of organic photovoltaics

    DEFF Research Database (Denmark)

    Corazza, Michael; Krebs, Frederik C; Gevorgyan, Suren A.

    2015-01-01

    A comprehensive outdoor study of polymer solar cells and modules for duration of one year was conducted. Different sample geometries and encapsulations were employed in order to study the spread in the lifetimes. The study is a complimentary report to previous work that focused on indoor ageing...... tests. Comparison of the indoor and outdoor lifetimes was performed by means of the o-diagram, which constitutes the initial steps towards establishing a method for predicting the lifetime of an organic photovoltaic device under real operational conditions based on a selection of accelerated indoor...

  3. Assessing electron beam sensitivity for SrTiO3 and La0.7Sr0.3MnO3 using electron energy loss spectroscopy.

    Science.gov (United States)

    Nord, Magnus; Vullum, Per Erik; Hallsteinsen, Ingrid; Tybell, Thomas; Holmestad, Randi

    2016-10-01

    Thresholds for beam damage have been assessed for La0.7Sr0.3MnO3 and SrTiO3 as a function of electron probe current and exposure time at 80 and 200kV acceleration voltage. The materials were exposed to an intense electron probe by aberration corrected scanning transmission electron microscopy (STEM) with simultaneous acquisition of electron energy loss spectroscopy (EELS) data. Electron beam damage was identified by changes of the core loss fine structure after quantification by a refined and improved model based approach. At 200kV acceleration voltage, damage in SrTiO3 was identified by changes both in the EEL fine structure and by contrast changes in the STEM images. However, the changes in the STEM image contrast as introduced by minor damage can be difficult to detect under several common experimental conditions. No damage was observed in SrTiO3 at 80kV acceleration voltage, independent of probe current and exposure time. In La0.7Sr0.3MnO3, beam damage was observed at both 80 and 200kV acceleration voltages. This damage was observed by large changes in the EEL fine structure, but not by any detectable changes in the STEM images. The typical method to validate if damage has been introduced during acquisitions is to compare STEM images prior to and after spectroscopy. Quantifications in this work show that this method possibly can result in misinterpretation of beam damage as changes of material properties.

  4. OH concentration in an atmospheric-pressure methane-air flame from molecular-beam mass spectrometry and laser-absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cattolica, R.J.; Yoon, S.; Knuth, E.L.

    1982-01-01

    In evaluating experimental techniques for studying premixed atmospheric-pressure methane-air flames, analysts demonstrated that the molecular-beam mass-spectrometry technique adequately measures OH concentration, given careful design of the sampling probe and appropriate consideration for possible mass interferences. Perturbation of the OH concentration profile using various sampling probes indicates the importance of minimizing the length of the sampling-orifice channel to reduce composition relaxation during sampling. The accuracy of the MBMS method was determined by comparing the results with those from a laser-absorption spectroscopy system.

  5. Measurement of angular divergence and ion species ratios of an rf-driven multicusp ion source for diagnostic neutral beam by Doppler shift spectroscopy

    Science.gov (United States)

    Yoo, S. J.; Yang, H. L.; Hwang, S. M.

    2000-03-01

    The ion species ratios as well as the angular divergences are measured by using a Doppler shift spectroscopy of Hα spectral lines, which originate from several different ions, such as H2+ and H3+ as well as H+, and are spectrally well resolvable from each other on the measured spectral window of detection system. The angular divergences of the ion beam components are determined from the linewidths of the measured emission lines, and the ratio of mixed species is deduced from the intensity ratio of each peak. The ion species ratios measured by the Doppler shift spectroscopy are cross checked by a mass analyzing magnet. The measurements are performed varying the input rf power and the operating source pressure.

  6. Beam-beam studies for FCC-hh

    CERN Document Server

    Barranco Garcia, Javier; Buffat, Xavier; Furuseth, Sondre Vik

    2017-01-01

    The Future Circular Collider hadron-hadron (FCC-hh) design study is currently exploring different IR design possibilities including round and flat optics or different crossing schemes. The present study intends to evaluate each scenario from the beam-beam effects point of view. In particular the single particle long term stability to maximize beam lifetimes and luminosity reach is used to quantify the differences. The impact of strong head on interactions on the beam quality and lifetime is addressed by means of GPU accelerated simulations code featuring a weak-strong 6-dimensional beam-beam interaction.

  7. Stroboscopic fluorescence lifetime imaging.

    Science.gov (United States)

    Holton, Mark D; Silvestre, Oscar R; Errington, Rachel J; Smith, Paul J; Matthews, Daniel R; Rees, Paul; Summers, Huw D

    2009-03-30

    We report a fluorescence lifetime imaging technique that uses the time integrated response to a periodic optical excitation, eliminating the need for time resolution in detection. A Dirac pulse train of variable period is used to probe the frequency response of the total fluorescence per pulse leading to a frequency roll-off that is dependent on the relaxation rate of the fluorophores. The technique is validated by demonstrating wide-field, realtime, lifetime imaging of the endocytosis of inorganic quantum dots by a cancer cell line. Surface charging of the dots in the intra-cellular environment produces a switch in the fluorescence lifetime from approximately 40 ns to technique offers lifetime based imaging at video rates with standard CCD cameras and has application in probing millisecond cell dynamics and in high throughput imaging assays.

  8. Measuring Lifetime Poverty

    OpenAIRE

    Michael Hoy; Buhong Zheng

    2008-01-01

    This paper presents an axiomatic framework for measuring life time poverty over multiple periods. For an individual, we argue that lifetime poverty is influenced by both the snapshot poverty of each period and the poverty level of the "permanent" lifetime consumption; it is also influenced by how poverty spells are distributed over the life time. Two obvious candidates for aggregation are to aggregate over time and then across individuals, or vice versa. For a society, we consider a path-inde...

  9. Online multispectral fluorescence lifetime values estimation and overlay onto tissue white-light video frames

    Science.gov (United States)

    Gorpas, Dimitris; Ma, Dinglong; Bec, Julien; Yankelevich, Diego R.; Marcu, Laura

    2016-03-01

    Fluorescence lifetime imaging has been shown to be a robust technique for biochemical and functional characterization of tissues and to present great potential for intraoperative tissue diagnosis and guidance of surgical procedures. We report a technique for real-time mapping of fluorescence parameters (i.e. lifetime values) onto the location from where the fluorescence measurements were taken. This is achieved by merging a 450 nm aiming beam generated by a diode laser with the excitation light in a single delivery/collection fiber and by continuously imaging the region of interest with a color CMOS camera. The interrogated locations are then extracted from the acquired frames via color-based segmentation of the aiming beam. Assuming a Gaussian profile of the imaged aiming beam, the segmentation results are fitted to ellipses that are dynamically scaled at the full width of three automatically estimated thresholds (50%, 75%, 90%) of the Gaussian distribution's maximum value. This enables the dynamic augmentation of the white-light video frames with the corresponding fluorescence decay parameters. A fluorescence phantom and fresh tissue samples were used to evaluate this method with motorized and hand-held scanning measurements. At 640x512 pixels resolution the area of interest augmented with fluorescence decay parameters can be imaged at an average 34 frames per second. The developed method has the potential to become a valuable tool for real-time display of optical spectroscopy data during continuous scanning applications that subsequently can be used for tissue characterization and diagnosis.

  10. Electron-Beam Atomic Spectroscopy for In Situ Measurements of Melt Composition for Refractory Metals: Analysis of Fundamental Physics and Plasma Models

    Science.gov (United States)

    Gasper, Paul Joseph; Apelian, Diran

    2015-04-01

    Electron-beam (EB) melting is used for the processing of refractory metals, such as Ta, Nb, Mo, and W. These metals have high value and are critical to many industries, including the semiconductor, aerospace, and nuclear industries. EB melting can also purify secondary feedstock, enabling the recovery and recycling of these materials. Currently, there is no method for measuring melt composition in situ during EB melting. Optical emission spectroscopy of the plasma generated by EB impact with vapor above the melt, a technique here termed electron-beam atomic spectroscopy, can be used to measure melt composition in situ, allowing for analysis of melt dynamics, facilitating improvement of EB melting processes and aiding recycling and recovery of these critical and high-value metals. This paper reviews the physics of the plasma generation by EB impact by characterizing the densities and energies of electrons, ions, and neutrals, and describing the interactions between them. Then several plasma models are introduced and their suitability to this application analyzed. Lastly, a potential method for calibration-free composition measurement is described and the challenges for implementation addressed.

  11. Corrosion Preventive Compounds Lifetime Testing

    Science.gov (United States)

    Hale, Stephanie M.; Kammerer, Catherine C.; Copp, Tracy L.

    2007-01-01

    Lifetime Testing of Corrosion Preventive Compounds (CPCs) was performed to quantify performance in the various environments to which the Space Shuttle Orbiter is exposed during a flight cycle. Three CPCs are approved for use on the Orbiter: RD Calcium Grease, Dinitrol AV-30, and Braycote 601 EF. These CPCs have been rigorously tested to prove that they mitigate corrosion in typical environments, but little information is available on how they perform in the unique combination of the coastal environment at the launch pad, the vacuum of low-earth orbit, and the extreme heat of reentry. Currently, there is no lifetime or reapplication schedule established for these compounds that is based on this combination of environmental conditions. Aluminum 2024 coupons were coated with the three CPCs and exposed to conditions that simulate the environments to which the Orbiter is exposed. Uncoated Aluminum 2024 coupons were exposed to the environmental conditions as a control. Visual inspection and Electro- Impedance Spectroscopy (EIS) were performed on the samples in order to determine the effectiveness of the CPCs. The samples were processed through five mission life cycles or until the visual inspection revealed the initiation of corrosion and EIS indicated severe degradation of the coating.

  12. Development of atomic spectroscopy technologies - The characteristics of laser beam propagation in resonant and near-resonant atomic media

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jai Hyung; Chang, Joon Sung; Lee, Won Kyu; Jeon, Jin Ho [Seoul National University, Seoul (Korea)

    2000-04-01

    We studied the conical emission(CE) in samarium(Sm) vapor under the near-resonant condition. The incident dye laser was tuned to the transition line, 4f{sup 6}6s{sup 2} {sup 7}F{sub 0} {yields} 4f{sup 6}({sup 7})6s6p({sup 1}P{sup 0}), of Sm atom. Using a high temperature oven, we could obtain the atomic density of 8 x 10{sup 14} atoms/cm{sup 3} large enough to observe the CE. We observed 1 {approx} 3 rings around the original laser beam and the number of the rings depended on the laser intensity, the laser wavelength and the atomic density. These results are attributed to the self-phase-modulation of the laser beam interacting with the near-resonant atomic medium. We obtain a simple expression that describes the dependence of the locations of the rings on the laser intensity. We compare the experimental results with this expression quantitatively and then estimate the nonlinear susceptibility of Sm vapor. The laser beam propagating through the resonant medium undergo severe deformation because of nonlinear interaction such as self-focusing, self-defocusing, etc. When strong pump beam coexists with the probe beam, propagation characteristics can be changed. We use samarium(Sm) vapor as the nonlinear medium. Probe laser is tuned around 4f{sup 6}s{sup 2} {sup 7}F{sub 0} {yields} 4f{sup 6}({sup 7}F)6s6p({sup 1}P{sup 0}) transition line of Sm (562.601 nm). Pump laser is tuned around 4f{sup 6}s{sup 2} {sup 7}F{sub 1} {yields} 4f{sup 6}({sup 7}F)6s6p({sup 1}P{sup 0}) transition line of Sm (572.019 nm). The probe and the pump beams are {lambda} -type configuration. The transmission and beam width of the probe beam is changed as the intensity and the detuning of the probe beam are varied. 17 refs., 16 figs., 1 tab. (Author)

  13. Femtosecond time-resolved X-ray absorption spectroscopy of liquid using a hard X-ray free electron laser in a dual-beam dispersive detection method.

    Science.gov (United States)

    Obara, Yuki; Katayama, Tetsuo; Ogi, Yoshihiro; Suzuki, Takayuki; Kurahashi, Naoya; Karashima, Shutaro; Chiba, Yuhei; Isokawa, Yusuke; Togashi, Tadashi; Inubushi, Yuichi; Yabashi, Makina; Suzuki, Toshinori; Misawa, Kazuhiko

    2014-01-13

    We present femtosecond time-resolved X-ray absorption spectroscopy of aqueous solution using a hard x-ray free electron laser (SACLA) and a synchronized Ti:sapphire laser. The instrumental response time is 200 fs, and the repetition rate of measurement is 10 Hz. A cylindrical liquid beam 100 μm in diameter of aqueous ammonium iron(III) oxalate solution is photoexcited at 400 nm, and the transient X-ray absorption spectra are measured in the K-edge region of iron, 7.10 - 7.26 keV, using a dual X-ray beam dispersive detection method. Each of the dual beams has the pulse energy of 1.4 μJ, and pump-induced absorbance change on the order of 10(-3) is successfully detected. The photoexcited iron complex exhibits a red shifted iron K-edge with the appearance time constant of 260 fs. The X-ray absorption difference spectra, with and without the pump pulses, are independent of time delay after 1.5 ps up to 100 ps, indicating that the photoexcited species is long-lived.

  14. Charm Lifetimes and Mixing

    CERN Document Server

    Cheung, H W K

    2002-01-01

    A review of the latest results on charm lifetimes and D-mixing is presented. The e+e- collider experiments are now able to measure charm lifetimes quite precisely, however comparisons with the latest results from fixed-target experiments show that possible systematic effects could be evident. The new D-mixing results from the B-factories have changed the picture that is emerging. Although the new world averaged value of y_CP is now consistent with zero, there is still a very interesting and favoured scenario if the strong phase difference between the Doubly-Cabibbo-suppressed and the Cabibbo-flavoured D0 -> Kpi decay is large.

  15. In-beam {gamma}-ray spectroscopy of two-step fragmentation reactions at relativistic energies. The case of {sup 36}Ca

    Energy Technology Data Exchange (ETDEWEB)

    Doornenbal, P.

    2007-10-23

    A two-step fragmentation experiment has been performed at GSI with the RISING setup. It combines the fragment separator FRS, which allows for the production of radioactive heavy ions at relativistic energies, with a high resolution {gamma}-spectrometer. This combination offers unique possibilities for nuclear structure investigations like the test of shell model predictions far from stability. Within the present work the question if the N=14(16) shell stabilisation in Z=8 oxygen isotopes and the N=20 shell quenching in {sup 32}Mg are symmetric with respect to the isospin projection quantum number Tz has been addressed. New {gamma}-ray decays were found in the neutron deficient {sup 36}Ca and {sup 36}K by impinging a radioactive ion beam of {sup 37}Ca on a secondary {sup 9}Be target. The fragmentation products were selected with the calorimeter telescope CATE and the emitted {gamma}-rays were measured with Ge Cluster, MINIBALL, and BaF{sub 2} HECTOR detectors. For {sup 36}Ca the 2{sub 1}{sup +}{yields}0{sub g.s.}{sup +} transition energy was determined to be 3015(16) keV, which is the heaviest T=2 nucleus from which {gamma}-spectroscopic information has been obtained so far. A comparison between the experimental 2{sub 1}{sup +} energies of {sup 36}Ca and its mirror nucleus {sup 36}S yielded a mirror energy difference of {delta}E{sub M}=-276(16) keV. In order to understand the large {delta}E{sub M} value, the experimental single-particle energies from the A=17, T=1/2 mirror nuclei were taken and applied onto modified isospin symmetric USD interactions in shell model calculations. These calculations were in agreement with the experimental result and showed that the experimental single-particle energies may account empirically for the one body part of Thomas-Ehrman and/or Coulomb effects. A method to extract the lifetime of excited states in fragmentation reactions was investigated. Therefore, the dependence between the lifetime of an excited state and the average de

  16. Measurements of urea and glucose in aqueous solutions with dual-beam near-infrared Fourier-transform spectroscopy

    DEFF Research Database (Denmark)

    Jensen, P.S.; Bak, J.

    2002-01-01

    of these two modes of operation. The concentrations of aqueous solutions of urea and glucose in the ranges 0-40 mg/dL and 0-250 mg/dL, respectively, were determined by principal component regression using both modes. The dual-beam technique eliminated instrumental variations present in the single...

  17. Real-Time Visualization of Tissue Surface Biochemical Features Derived From Fluorescence Lifetime Measurements.

    Science.gov (United States)

    Gorpas, Dimitris; Ma, Dinglong; Bec, Julien; Yankelevich, Diego R; Marcu, Laura

    2016-08-01

    Fiber based fluorescence lifetime imaging has shown great potential for intraoperative diagnosis and guidance of surgical procedures. Here we describe a novel method addressing a significant challenge for the practical implementation of this technique, i.e., the real-time display of the quantified biochemical or functional tissue properties superimposed on the interrogated area. Specifically, an aiming beam (450 nm) generated by a continuous-wave laser beam was merged with the pulsed fluorescence excitation light in a single delivery/collection fiber and then imaged and segmented using a color-based algorithm. We demonstrate that this approach enables continuous delineation of the interrogated location and dynamic augmentation of the acquired frames with the corresponding fluorescence decay parameters. The method was evaluated on a fluorescence phantom and fresh tissue samples. Current results demonstrate that 34 frames per second can be achieved for augmenting videos of 640 × 512 pixels resolution. Also we show that the spatial resolution of the fluorescence lifetime map depends on the tissue optical properties, the scanning speed, and the frame rate. The dice similarity coefficient between the fluorescence phantom and the reconstructed maps was estimated to be as high as 93%. The reported method could become a valuable tool for augmenting the surgeon's field of view with diagnostic information derived from the analysis of fluorescence lifetime data in real-time using handheld, automated, or endoscopic scanning systems. Current method provides also a means for maintaining the tissue light exposure within safety limits. This study provides a framework for using an aiming beam with other point spectroscopy applications.

  18. Our Allotted Lifetimes

    Science.gov (United States)

    Gould, Stephen Jay

    1977-01-01

    It is suggested that measured by the internal clock of heartbeats or breathing, all mammals live a similar lifespan. This is based on the fact that mammals, regardless of size, breathe about 200 million times in their lifetime at a rate of 1 breath for every 4 heartbeats. (AJ)

  19. Charge deep-level transient spectroscopy study of high-energy-electron-beam-irradiated hydrogenated amorphous silicon

    NARCIS (Netherlands)

    Klaver, A.; Nádaždy, V.; Zeman, M.; Swaaiij, R.A.C.M.M.

    2006-01-01

    We present a study of changes in the defect density of states in hydrogenated amorphous silicon (a-Si:H) due to high-energy electron irradiation using charged deep-level transient spectroscopy. It was found that defect states near the conduction band were removed, while in other band gap regions the

  20. Analysis of the fine structure of Sn11 +-Sn14 + ions by optical spectroscopy in an electron-beam ion trap

    Science.gov (United States)

    Windberger, A.; Torretti, F.; Borschevsky, A.; Ryabtsev, A.; Dobrodey, S.; Bekker, H.; Eliav, E.; Kaldor, U.; Ubachs, W.; Hoekstra, R.; Crespo López-Urrutia, J. R.; Versolato, O. O.

    2016-07-01

    We experimentally re-evaluate the fine structure of Sn11 +-Sn14 + ions. These ions are essential in bright extreme-ultraviolet (EUV) plasma-light sources for next-generation nanolithography, but their complex electronic structure is an open challenge for both theory and experiment. We combine optical spectroscopy of magnetic dipole M 1 transitions, in a wavelength range covering 260 to 780 nm, with charge-state selective ionization in an electron beam ion trap. Our measurements confirm the predictive power of ab initio calculations based on Fock space coupled cluster theory. We validate our line identification using semiempirical cowan calculations with adjustable wave-function parameters. Available Ritz combinations further strengthen our analysis. Comparison with previous work suggests that line identifications in the EUV need to be revisited.

  1. In-beam γ-ray Spectroscopy of {sup 30}P via the {sup 28}Si({sup 3}He,pγ){sup 30}P Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Mcneice, E.; Setoodehnia, K. [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada); Singh, B., E-mail: ndgroup@mcmaster.ca [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada); Abe, Y. [Institute of Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577 (Japan); Binh, D.N. [Center for Nuclear Study (CNS), the University of Tokyo, Wako Branch at RIKEN, Wako, Saitama 351-0198 (Japan); Chen, A.A.; Chen, J. [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada); Cherubini, S. [INFN-Laboratori Nazionali del Sud and Dipartimento di Fisica ed Astronomia, Università di Catania, 95123 Catania (Italy); Center for Nuclear Study (CNS), the University of Tokyo, Wako Branch at RIKEN, Wako, Saitama 351-0198 (Japan); Fukuoka, S. [Institute of Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577 (Japan); Hashimoto, T. [Center for Nuclear Study (CNS), the University of Tokyo, Wako Branch at RIKEN, Wako, Saitama 351-0198 (Japan); Hayakawa, T. [Japan Atomic Energy Agency (JAEA), Tokai–mura, Ibaraki 319-1195 (Japan); Ishibashi, Y.; Ito, Y. [Institute of Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577 (Japan); Kahl, D. [Center for Nuclear Study (CNS), the University of Tokyo, Wako Branch at RIKEN, Wako, Saitama 351-0198 (Japan); Komatsubara, T. [Institute of Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577 (Japan); Kubono, S. [Nishina Center, the Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-0198 (Japan); Moriguchi, T.; Nagae, D.; Nishikiori, R.; Niwa, T. [Institute of Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577 (Japan); and others

    2014-06-15

    The level structure of {sup 30}P up to 8.25 MeV was investigated via in-beam γ-ray spectroscopy using the {sup 28}Si({sup 3}He,pγ){sup 30}P reaction at 9 MeV at the University of Tsukuba Tandem Accelerator Complex in Japan. An energy level scheme was deduced from γ-γ coincidence measurements. 47 new transitions have been observed from the previously known states (mostly resonances), thereby reducing the uncertainties in the excitation energies of 17 states from 3 to 10 keV to values of < 1 keV. Furthermore, spin assignments based on measurements of γ-ray angular distributions and γ-γ directional correlation of oriented nuclei (DCO ratios) were made for several observed levels of {sup 30}P.

  2. Polymeric membrane studied using slow positron beam

    Energy Technology Data Exchange (ETDEWEB)

    Hung, W.-S.; Lo, C.-H. [R and D Center for Membrane Technology, Chung Yuan Christian University, Chung-Li 32023, Taiwan (China); Department of Chemical Engineering, Chung Yuan Christian University, Chung-Li 32023, Taiwan (China); Cheng, M.-L. [Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110 (United States); Department of Chemical Engineering and Materials Science, Yuan Ze University, Chung-Li 32003, Taiwan (China); Chen Hongmin; Liu Guang; Chakka, Lakshmi [Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110 (United States); Nanda, D.; Tung, K.-L.; Huang, S.-H.; Lee, Kueir-Rarn; Lai, J.-Y. [R and D Center for Membrane Technology, Chung Yuan Christian University, Chung-Li 32023, Taiwan (China); Department of Chemical Engineering, Chung Yuan Christian University, Chung-Li 32023, Taiwan (China); Sun Yiming [R and D Center for Membrane Technology, Chung Yuan Christian University, Chung-Li 32023, Taiwan (China); Department of Chemical Engineering and Materials Science, Yuan Ze University, Chung-Li 32003, Taiwan (China); Yu Changcheng [R and D Center for Membrane Technology, Chung Yuan Christian University, Chung-Li 32023, Taiwan (China); Department of Physics, Chung Yuan Christian University, Chung-Li 32023, Taiwan (China); Zhang Renwu [Physical Science Department, Southern Utah University, Cedar City, UT 84720 (United States); Jean, Y.C. [R and D Center for Membrane Technology, Chung Yuan Christian University, Chung-Li 32023, Taiwan (China); Department of Chemical Engineering, Chung Yuan Christian University, Chung-Li 32023, Taiwan (China); Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110 (United States)], E-mail: jeany@umkc.edu

    2008-10-31

    A radioisotope slow positron beam has been built at the Chung Yuan Christian University in Taiwan for the research and development in membrane science and technology. Doppler broadening energy spectra and positron annihilation lifetime have been measured as a function of positron energy up to 30 keV in a polyamide membrane prepared by the interfacial polymerization between triethylenetetraamine (TETA) and trimesoyl chloride (TMC) on modified porous polyacrylonitrile (PAN) asymmetric membrane. The multilayer structures and free-volume depth profile for this asymmetric membrane system are obtained. Positron annihilation spectroscopy coupled with a slow beam could provide new information about size selectivity of transporting molecules and guidance for molecular designs in polymeric membranes.

  3. Exciton lifetime measurements on single silicon quantum dots.

    Science.gov (United States)

    Sangghaleh, Fatemeh; Bruhn, Benjamin; Schmidt, Torsten; Linnros, Jan

    2013-06-01

    We measured the exciton lifetime of single silicon quantum dots, fabricated by electron beam lithography, reactive ion etching and oxidation. The observed photoluminescence decays are of mono-exponential character with a large variation (5-45 μs) from dot to dot, even for the same emission energy. We show that this lifetime variation may be the origin of the heavily debated non-exponential (stretched) decays typically observed for ensemble measurements.

  4. Total and partial cross sections of the $^{112}$Sn($\\alpha,\\gamma$)$^{116}$Te reaction measured via in-beam $\\gamma$-ray spectroscopy

    CERN Document Server

    Netterdon, L; Scholz, P; Zilges, A

    2015-01-01

    An extended database of experimental data is needed to address uncertainties of the nuclear-physics input parameters for Hauser-Feshbach calculations. Especially $\\alpha$+nucleus optical model potentials at low energies are not well known. The in-beam technique with an array of high-purity germanium (HPGe) detectors was successfully applied to the measurement of absolute cross sections of an ($\\alpha$,$\\gamma$) reaction on a heavy nucleus at sub-Coulomb energies. The total and partial cross-section values were measured by means of in-beam $\\gamma$-ray spectroscopy. Total and partial cross sections were measured at four different $\\alpha$-particle energies from $E_\\alpha = 10.5$ MeV to $E_\\alpha = 12$ MeV. The measured total cross-section values are in excellent agreement with previous results obtained with the activation technique, which proves the validity of the applied method. The experimental data was compared to Hauser-Feshbach calculations using the nuclear reaction code TALYS. A modified version of the...

  5. Positronium lifetime in polymers

    CERN Document Server

    Camacho, Abel

    2004-01-01

    A model describing the relationship between the ortho--positronium lifetime and the volume of a void, located in a synthetic zeolite, is analyzed. Our idea, which allows us to take into account the effects of temperature, comprises the introduction of a non--hermitian term in the Hamiltonian, which accounts for the annihilation of the ortho--positronium. The predictions of the present model are also confronted against an already known experimental result.

  6. Lifetime of {sup 44}Ti as probe for supernova models

    Energy Technology Data Exchange (ETDEWEB)

    Goerres, J.; Meissner, J.; Schatz, H.; Stech, E.; Tischhauser, P.; Wiescher, M. [Univ. of Notre Dame, Notre Dame, IN (United States); Bazin, D.; Harkewicz, R.; Hellstroem, M.; Sherrill, B.; Steiner, M. [Michigan State Univ., East Lansing, MI (United States); Boyd, R.N. [Ohio State Univ., Columbus, OH (United States); Buchmann, L. [TRIUMF, Vancouver, BC (Canada); Hartmann, D.H. [Clemson Univ., Clemson, SC (United States); Hinnefeld, J.D. [Indiana Univ. South Bend, South Bend, IN (United States)

    1998-06-01

    The recent observation of {sup 44}Ti radioactivity in the supernova remnant Cassiopeia A with the Compton Gamma Ray Observatory allows the determination of the absolute amount of {sup 44}Ti. This provides a test for current supernova models. The main uncertainty is the lifetime of {sup 44}Ti. We report a new measurement of the lifetime of {sup 44}Ti applying a novel technique. A mixed radioactive beam containing {sup 44}Ti as well as {sup 22}Na was implanted and the resulting {gamma}-activity was measured. This allowed the determination of the lifetime of {sup 44}Ti relative to the lifetime of {sup 22}Na, {tau} = (87.0 {+-} 1.9) y. With this lifetime, the {sup 44}Ti abundance agrees with theoretical predictions within the remaining observational uncertainties. (orig.)

  7. Point defects in MnSi and YBCO studied by Doppler Broadening Spectroscopy using a positron beam

    Energy Technology Data Exchange (ETDEWEB)

    Reiner, Markus

    2015-10-28

    The positron beam NEPOMUC was used in order to investigate MnSi and YBa{sub 2}Cu{sub 3}O{sub 7-δ} (YBCO) single crystals. The Doppler broadening of the annihilation radiation of electron-positron pairs was analyzed. Thus, the concentration of Mn vacancies in MnSi crystals was determined. In thin YBCO films, the Doppler broadening is correlated with the oxygen deficiency δ. Its spatial distribution and its high-temperature behavior were studied using positrons.

  8. Lifetime of 19Ne*(4.03 MeV)

    CERN Document Server

    Kanungo, R; Andreyev, A N; Ball, G C; Chakravarthy, R S; Chicoine, M; Churchman, R; Davids, B; Forster, J S; Gujrathi, S; Hackman, G; Howell, D; Leslie, J R; Morton, A C; Mythili, S; Pearson, C J; Ressler, J J; Ruiz, C; Savajols, H; Schumaker, M A; Tanihata, I; Walden, P L; Yen, S

    2006-01-01

    The Doppler-shift attenuation method was applied to measure the lifetime of the 4.03 MeV state in 19Ne. Utilizing a 3He-implanted Au foil as a target, the state was populated using the 20Ne(3He,alpha)19Ne reaction in inverse kinematics at a 20Ne beam energy of 34 MeV. De-excitation gamma rays were detected in coincidence with alpha particles. At the 1 sigma level, the lifetime was determined to be 11 +4, -3 fs and at the 95.45% confidence level the lifetime is 11 +8, -7 fs.

  9. Nuclear physics experiments with in-beam fast-timing and plunger techniques

    Science.gov (United States)

    Sotty, C.

    2017-06-01

    Nuclear lifetime and g factor are crucial observables in nuclear physics, as they give access to the excited states nuclear wave functions using the well-known electromagnetic transition operators. Thus, they are benchmarks to validate or discard nuclear structure theories. During the last decades, the evolution of the nuclear instruments and methods gave birth to several techniques used to measure lifetimes and moments. Among them, the in-beam Fast Electronic Scintillation Timing (FEST) technique is used to measure lifetimes of nuclear states in the picosecond to nanosecond range. Plunger devices originally developed to perform lifetime measurements of excited states in the picosecond range using the Recoil Distance Doppler Shift (RDDS) are now also employed to measure g factor using the new Time-Differential Recoil-In-Vacuum (TDRIV) technique. Recently commissioned, the ROmanian array for SPectroscopy in HEavy ion REactions (ROSPHERE) is dedicated to perform γ-ray spectroscopy, specially suited for lifetime measurements using the RDDS and in-beam fast-timing techniques at the 9 MV Bucharest-Tandem accelerator facility of the Horia Hulubei National Institute of Physics and Nuclear Engineering (IFIN-HH). An introduction of above-mentioned techniques is provided and selected results are illustrating them with physics cases. The in-beam fast-timing and RDDS techniques are described using lifetime measurements respectively in 67Cu and 120Te measured at the 9 MV Bucharest-Tandem accelerator. Finally, the precise g factor measurement of the first-excited state in 24Mg using by the new TDRIV technique at the ALTO-Tandem Orsay facility is presented.

  10. Annihilation detector for an in-beam spectroscopy apparatus to measure the ground state hyperfine splitting of antihydrogen

    Science.gov (United States)

    Sauerzopf, Clemens; Capon, Aaron A.; Diermaier, Martin; Fleck, Markus; Kolbinger, Bernadette; Malbrunot, Chloé; Massiczek, Oswald; Simon, Martin C.; Vamosi, Stefan; Zmeskal, Johann; Widmann, Eberhard

    2017-02-01

    The matter-antimatter asymmetry observed in the universe today still lacks a quantitative explanation. One possible mechanism that could contribute to the observed imbalance is a violation of the combined Charge-, Parity- and Time symmetries (CPT). A test of CPT symmetry using anti-atoms is being carried out by the ASACUSA-CUSP collaboration at the CERN Antiproton Decelerator using a low temperature beam of antihydrogen-the most simple atomic system built only of antiparticles. While hydrogen is the most abundant element in the universe, antihydrogen is produced in very small quantities in a laboratory framework. A detector for in-beam measurements of the ground state hyperfine structure of antihydrogen has to be able to detect very low signal rates within high background. To fulfil this challenging task, a two layer barrel hodoscope detector was developed. It is built of plastic scintillators with double sided readout via Silicon Photomultipliers (SiPMs). The SiPM readout is done using novel, compact and cost efficient electronics that incorporate power supply, amplifier and discriminator on a single board. This contribution will evaluate the performance of the new hodoscope detector.

  11. Development of a multipurpose beam foil spectroscopy set-up for the low cross-section measurements

    Science.gov (United States)

    Sharma, Gaurav; Nandi, T.; Berry, H. G.; Puri, Nitin K.

    2016-08-01

    A multipurpose facility for low cross section measurements has been developed at Inter University Accelerator Centre, New Delhi, India. The facility consists of a multipurpose miniature chamber equipped with 1 m focal length normal incidence Monochromator and charge coupled device based detection system which has been aligned to realize the best resolution of the spectrometer. The chamber in this facility collects radiation 100 times more efficiently from the older system, without using any extra focusing mirror assembly. It is ensured to have the provision of mounting an X-ray detector and the spectrometer transverse to the beam direction simultaneously in the same chamber. The atomic spectroscopic studies can be performed by interaction of ions beams with both thin foil and gas targets. Provision for using photomultiplier tube instead of charge coupled device, is employed in the system depending on the condition of the source strength or other detection issues. We observed the essence of a very weak atomic phenomenon, a triply excited autoionizing forbidden transition, using the above facility to demonstrate its capability for measuring such low cross section phenomena. The present developed facility covers a large spectroscopic region from X-rays to the near infrared (0.1-10,000 Å).

  12. Admittance spectroscopy of Mg-doped GaN grown by molecular beam epitaxy using RF nitrogen sources

    CERN Document Server

    Kim, D J; Kim, K H; Bojarczuk, N A; Karasinski, J; Guha, S; Lee, H G

    1999-01-01

    Thermal activation energies of Mg in GaN grown using RF nitrogen source with varying Mg flux were examined using an admittance spectroscopy technique. There was no noticeable difference or trend in the activation energy with varying Mg flux. The thermal activation energy for GaN:Mg was approx 115 meV under the investigated Mg flux range. Negligible persistent photo-conductivity and yellow luminescence peak in PL observed in the samples suggest possible reduction of the thermal activation energies compared to the values in the literature.

  13. Spins, charge radii and magnetic moments of neutron-rich Mn isotopes measured with bunched beam Collinear Laser Spectroscopy

    CERN Document Server

    AUTHOR|(CDS)2085887; Heylen, Hanne

    In this work, the odd-even $^{51–63}$Mn isotopes have been analyzed using collinear laser spectroscopy, from which the magnetic dipole moment and the change in change in mean square charge radius can be determined. The magnetic moment is very sensitive to the composition of the total nuclear wave function, while the charge radius gives information about the relative size and degree of deformation of the nucleus. An additional advantage of collinear laser spectroscopy is the possibility of direct measurement of the nuclear spin. The main motivation behind the study of these isotopes is to investigate the change in nuclear structure when approaching neutron number N = 40. This region is of interest due to the apparent doubly magic nature of $^{68}$Ni , which is not seen in the N = 40 isotopes of $^{26}$Fe and $^{24}$Cr. Mn, situated between these elements, offers another perspective due to its uncoupled proton. Based on the observed spectra and extracted moments, spins were assigned to $^{59,61,63}$Mn. The ex...

  14. The Sprint to Lifetime Sports

    Science.gov (United States)

    Ernst, Leonard

    1973-01-01

    Describes the trend in high school physical education programs toward lifetime sports, defined by the author as physical activities that will serve the interests of students for a lifetime. Included are a special report on program costs and a model of a performance-based lifetime sports program. (Author/DN)

  15. Simulations of beam-beam and beam-wire interactions in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung J.; Sen, Tanaji; /Fermilab; Abreu, Natalia P.; Fischer, Wolfram; /Brookhaven

    2009-02-01

    The beam-beam interaction is one of the dominant sources of emittance growth and luminosity lifetime deterioration. A current carrying wire has been proposed to compensate long-range beam-beam effects in the LHC and strong localized long-range beam-beam effects are experimentally investigated in the RHIC collider. Tune shift, beam transfer function, and beam loss rate are measured in dedicated experiments. In this paper, they report on simulations to study the effect of beam-wire interactions based on diffusive apertures, beam loss rates, and beam transfer function using a parallelized weak-strong beam simulation code (BBSIMC). The simulation results are compared with measurements performed in RHIC during 2007 and 2008.

  16. Characterization of ion-irradiated ODS Fe–Cr alloys by doppler broadening spectroscopy using a positron beam

    Energy Technology Data Exchange (ETDEWEB)

    Parente, P.; Leguey, T. [Departamento de Física and IAAB, Universidad Carlos III de Madrid, 28911 Leganés (Spain); Castro, V. de, E-mail: vanessa.decastro@uc3m.es [Departamento de Física and IAAB, Universidad Carlos III de Madrid, 28911 Leganés (Spain); Gigl, T.; Reiner, M.; Hugenschmidt, C. [FRM II and Physics Department, Technische Universität München, 85747 Garching (Germany); Pareja, R. [Departamento de Física and IAAB, Universidad Carlos III de Madrid, 28911 Leganés (Spain)

    2015-09-15

    The damage profile of oxide dispersion strengthened steels after single-, or simultaneous triple-ion irradiation at different conditions has been characterized using a low energy positron beam in order to provide information on microstructural changes induced by irradiation. Doppler broadening and coincident Doppler broadening measurements of the positron annihilation line have been performed on different Fe–Cr–(W,Ti) alloys reinforced with Y{sub 2}O{sub 3}, to identify the nature and stability of irradiation-induced open-volume defects and their possible association with the oxide nanoparticles. It was found that irradiation induced vacancy clusters are associated with Cr atoms. The results are of highest interest for modeling the damage induced by 14 MeV neutrons in reduced activation Fe–Cr alloys relevant for fusion devices.

  17. DAFNE Lifetime Optimization with Octupoles and Compensating Wires

    CERN Document Server

    Milardi, C; Preger, M A; Raimondi, P; Zobov, M; Shatilov, D

    2008-01-01

    Long-range beam-beam interactions (parasitic crossings) were one of the main luminosity performance limitations for the lepton F-factory DAFNE in its original configuration. In particular, the parasitic crossings led to a substantial lifetime reduction of both beams in collision. This puts a limit on the maximum storable current and, as a consequence, on the achievable peak and integrated luminosity. In order to mitigate the problem, numerical and experimental studies of the parasitic crossings compensation by current-carrying wires have been done. During the operation for the KLOE experiment two such wires have been installed at both ends of the interaction region. They produced a relevant improvement in the lifetime of the weak beam (positrons) at the maximum current of the strong one (electrons) without luminosity loss, in agreement with the numerical predictions. The same compensating mechanism has been adopted during the run for the FINUDA experiment as well, with less evident benefits than in the previo...

  18. Recent and Past Experiences with Beam-Beam Effects at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Minty, Michiko G

    1999-11-22

    Proton beam stability when in collision with high current electron bunches was of foremost concern during the design stages of the HERA collider[1]. In initial commissioning the beam-beam interaction proved to be a key factor in determining the lifetime of the proton beam. It was quickly ascertained[2] that the proton beam lifetime in collision could be substantially increased by both matching the electron and proton beam sizes ({sigma}) at the interaction points (IPs) and by carefully centering the beams. Presently, proton beam life times of hundreds of hours are routinely observed. In the near future, the accelerators will be upgraded[3] to include new low-{beta} insertions and to allow for yet higher beam currents. Key factors affecting the stability of colliding proton beams will be described as well as recent experiments performed to explore at high electron beam currents new regimes of the proton beam-beam limit at HERA.

  19. Lifetimes and HQE

    CERN Document Server

    Lenz, Alexander

    2014-01-01

    Kolya Uraltsev was one of the inventors of the Heavy Quark Expansion (HQE), that describes inclusive weak decays of hadrons containing heavy quarks and in particular lifetimes. Besides giving a pedagogic introduction to the subject, we review the development and the current status of the HQE, which just recently passed several non-trivial experimental tests with an unprecedented precision. In view of many new experimental results for lifetimes of heavy hadrons, we also update several theory predictions: $\\tau (B^+) / \\tau (B_d) = 1.04^{+0.05}_{-0.01} \\pm 0.02 \\pm 0.01$, $\\tau (B_s) / \\tau (B_d) = 1.001 \\pm 0.002$, $\\tau (\\Lambda_b)/ \\tau (B_d) = 0.935 \\pm 0.054$ and $\\bar {\\tau} (\\Xi_b^0) / \\bar{\\tau} (\\Xi_b^+) = 0.95 \\pm 0.06$. The theoretical precision is currently strongly limited by the unknown size of the non-perturbative matrix elements of four-quark operators, which could be determined with lattice simulations.

  20. Lithium beam diagnostic system on the COMPASS tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Anda, G.; Bencze, A. [Wigner – RCP, HAS, Budapest (Hungary); Berta, M., E-mail: bertam@sze.hu [Institute of Plasma Physics AS CR, Prague (Czech Republic); Széchenyi István University, Győr (Hungary); Dunai, D. [Wigner – RCP, HAS, Budapest (Hungary); Hacek, P. [Institute of Plasma Physics AS CR, Prague (Czech Republic); Faculty of Mathematics and Physics, Charles University in Prague, Prague (Czech Republic); Krbec, J. [Institute of Plasma Physics AS CR, Prague (Czech Republic); Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague (Czech Republic); Réfy, D.; Krizsanóczi, T.; Bató, S.; Ilkei, T.; Kiss, I.G.; Veres, G.; Zoletnik, S. [Wigner – RCP, HAS, Budapest (Hungary)

    2016-10-15

    Highlights: • Li-beam diagnostic system on the COMPASS tokamak is an improved and compact system to allow testing of Atomic Beam Probe. • The possibility to measure background corrected density profiles on the few microseconds time scale. • First Li-beam diagnostic system with recirculating neutralizer. • The system includes the redesigned ion source with longer lifetime. - Abstract: An improved lithium beam based beam emission spectroscopy system – installed on COMPASS tokamak – is described. The beam energy enhanced up to 120 keV for Atomic Beam Probe measurement. The size of the ion source is doubled, using a newly developed thermionic heater instead of the conventionally used heating (tungsten or molybdenum) filament. The neutralizer is also improved. It produces the same sodium vapor in a cell but minimize the loss condensing the vapor on a cold surface which is led back (in fluid state) into the sodium oven. This way we call it recirculating neutralizer. The observation system consists of a CCD camera and an avalanche photodiode array.

  1. Simultaneous Counter-Ion Co-Deposition a Technique Enabling Matrix Isolation Spectroscopy Studies Using Low-Energy Beams of Mass-Selected Ions

    Science.gov (United States)

    Ludwig, Ryan M.; Moore, David T.

    2014-06-01

    Matrix isolation spectroscopy was first developed in Pimentel's group during the 1950's to facilitate spectroscopic studies of transient species. Cryogenic matrices of condensed rare gases provide an inert chemical environment with facile energy dissipation and are transparent at all wavelengths longer than vacuum UV, making them ideal for studying labile and reactive species such as radicals, weakly bound complexes, and ions. Since frozen rare gases are poor electrolytes, studies of ions require near-equal populations of anions and cations in order to stabilize the number densities required for spectroscopic experiments. Many techniques for generation of ions for using in matrix isolation studies satisfy this criterion intrinsically, however when ion beams generated in external sources are deposited, the counter-ions typically arise via secondary processes that are at best loosely controlled. It has long been recognized that it would be desirable to stabilize deposition of mass-selected ions generated in an external source using simultaneous co-deposition of a beam of counter-ions, however previous attempts to achieve this have been reported as unsuccessful. The Moore group at Lehigh has demonstrated successful experiments of this type, using mass-selected anions generated from a metal cluster source, co-deposited with a balanced current of cations generated in a separate electron ionization source. This talk will focus on the details of the technique, and present some results from proof-of-concept studies on anionic copper carbonyl complexes formed in argon matrices following co-deposition of Cu- with Ar+ or Kr+. Funding support from NSF CAREER Award CHE-0955637 is gratefully acknowledged. Whittle et al., J. Chem. Phys. 22, p.1943 (1954); Becker et al., J. Chem. Phys. 25, p.224 (1956). Godbout et al., J. Chem. Phys. 96, p.2892 (1996). Sabo et al., Appl. Spectrosc. 45, p. 535 (1991).

  2. Radiative Rotational Lifetimes and State-Resolved Relative Detachment Cross Sections from Photodetachment Thermometry of Molecular Anions in a Cryogenic Storage Ring

    Science.gov (United States)

    Meyer, C.; Becker, A.; Blaum, K.; Breitenfeldt, C.; George, S.; Göck, J.; Grieser, M.; Grussie, F.; Guerin, E. A.; von Hahn, R.; Herwig, P.; Krantz, C.; Kreckel, H.; Lion, J.; Lohmann, S.; Mishra, P. M.; Novotný, O.; O'Connor, A. P.; Repnow, R.; Saurabh, S.; Schwalm, D.; Schweikhard, L.; Spruck, K.; Sunil Kumar, S.; Vogel, S.; Wolf, A.

    2017-07-01

    Photodetachment thermometry on a beam of OH- in a cryogenic storage ring cooled to below 10 K is carried out using two-dimensional frequency- and time-dependent photodetachment spectroscopy over 20 min of ion storage. In equilibrium with the low-level blackbody field, we find an effective radiative temperature near 15 K with about 90% of all ions in the rotational ground state. We measure the J =1 natural lifetime (about 193 s) and determine the OH- rotational transition dipole moment with 1.5% uncertainty. We also measure rotationally dependent relative near-threshold photodetachment cross sections for photodetachment thermometry.

  3. Dielectric spectroscopy of electron beam deposited yttrium oxide films examined in metal–insulator–metal sandwich type structures

    Energy Technology Data Exchange (ETDEWEB)

    Wiktorczyk, Tadeusz, E-mail: Tadeusz.Wiktorczyk@pwr.wroc.pl; Biegański, Piotr

    2014-01-31

    This report describes the dielectric properties of electron-beam deposited Y{sub 2}O{sub 3} thin films examined in metal–insulator–metal-type structures fabricated onto quartz substrates. The dielectric measurements have been carried out in the frequency domain from 10 mHz to 10 MHz, with a frequency response analyser. Frequency characteristics of the complex capacitance, as well as Cole–Cole and Nyquist graphs, have been presented and discussed for the temperature range 398–523 K. The results have been analyzed in terms of equivalent circuit models containing resistance–capacitance and constant phase elements (CPE). We have determined the values of the resistance, capacitance and CPE, which characterize the Y{sub 2}O{sub 3} film and near-electrode regions. It has been shown that for high frequencies/low temperatures the dielectric properties are connected with Y{sub 2}O{sub 3} film, while for low frequencies/high temperatures the dielectric response is dominated by the near-electrode regions. In the frequency range 0.1–10 MHz the important contribution of series resistance of electrodes and leads has been observed. - Highlights: • We examine the Al/Y{sub 2}O{sub 3}/Al thin film capacitors for frequency range 10 mHz–10 MHz. • The dielectric data are assigned to Y{sub 2}O{sub 3} and to metal/insulator interfaces. • The capacitance, resistance and constant phase elements describe their properties. • The values of these elements are estimated for temperatures from 398 K to 523 K.

  4. Scanning Tunneling Microscopy and Spectroscopy of Air Exposure Effects on Molecular Beam Epitaxy Grown WSe2 Monolayers and Bilayers.

    Science.gov (United States)

    Park, Jun Hong; Vishwanath, Suresh; Liu, Xinyu; Zhou, Huawei; Eichfeld, Sarah M; Fullerton-Shirey, Susan K; Robinson, Joshua A; Feenstra, Randall M; Furdyna, Jacek; Jena, Debdeep; Xing, Huili Grace; Kummel, Andrew C

    2016-04-26

    The effect of air exposure on 2H-WSe2/HOPG is determined via scanning tunneling microscopy (STM). WSe2 was grown by molecular beam epitaxy on highly oriented pyrolytic graphite (HOPG), and afterward, a Se adlayer was deposited in situ on WSe2/HOPG to prevent unintentional oxidation during transferring from the growth chamber to the STM chamber. After annealing at 773 K to remove the Se adlayer, STM images show that WSe2 layers nucleate at both step edges and terraces of the HOPG. Exposure to air for 1 week and 9 weeks caused air-induced adsorbates to be deposited on the WSe2 surface; however, the band gap of the terraces remained unaffected and nearly identical to those on decapped WSe2. The air-induced adsorbates can be removed by annealing at 523 K. In contrast to WSe2 terraces, air exposure caused the edges of the WSe2 to oxidize and form protrusions, resulting in a larger band gap in the scanning tunneling spectra compared to the terraces of air-exposed WSe2 monolayers. The preferential oxidation at the WSe2 edges compared to the terraces is likely the result of dangling edge bonds. In the absence of air exposure, the dangling edge bonds had a smaller band gap compared to the terraces and a shift of about 0.73 eV in the Fermi level toward the valence band. However, after air exposure, the band gap of the oxidized WSe2 edges became about 1.08 eV larger than that of the WSe2 terraces, resulting in the electronic passivation of the WSe2.

  5. Design of an ultrahigh vacuum transfer mechanism to interconnect an oxide molecular beam epitaxy growth chamber and an x-ray photoemission spectroscopy analysis system

    Energy Technology Data Exchange (ETDEWEB)

    Rutkowski, M. M.; Zeng Zhaoquan [Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States); McNicholas, K. M. [Department of Electrical and Computer Engineering, Ohio State University, Columbus, Ohio 43210 (United States); Brillson, L. J. [Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States); Department of Electrical and Computer Engineering, Ohio State University, Columbus, Ohio 43210 (United States)

    2013-06-15

    We designed a mechanism and the accompanying sample holders to transfer between a VEECO 930 oxide molecular beam epitaxy (MBE) and a PHI Versa Probe X-ray photoemission spectroscopy (XPS) chamber within a multiple station growth, processing, and analysis system through ultrahigh vacuum (UHV). The mechanism consists of four parts: (1) a platen compatible with the MBE growth stage, (2) a platen compatible with the XPS analysis stage, (3) a sample coupon that is transferred between the two platens, and (4) the accompanying UHV transfer line. The mechanism offers a robust design that enables transfer back and forth between the growth chamber and the analysis chamber, and yet is flexible enough to allow transfer between standard sample holders for thin film growth and masked sample holders for making electrical contacts and Schottky junctions, all without breaking vacuum. We used this mechanism to transfer a barium strontium titanate thin film into the XPS analysis chamber and performed XPS measurements before and after exposing the sample to the air. After air exposure, a thin overlayer of carbon was found to form and a significant shift ({approx}1 eV) in the core level binding energies was observed.

  6. In-beam γ -ray spectroscopy of the neutron-rich platinum isotope 200Pt toward the N =126 shell gap

    Science.gov (United States)

    John, P. R.; Valiente-Dobón, J. J.; Mengoni, D.; Modamio, V.; Lunardi, S.; Bazzacco, D.; Gadea, A.; Wheldon, C.; Rodríguez, T. R.; Alexander, T.; de Angelis, G.; Ashwood, N.; Barr, M.; Benzoni, G.; Birkenbach, B.; Bizzeti, P. G.; Bizzeti-Sona, A. M.; Bottoni, S.; Bowry, M.; Bracco, A.; Browne, F.; Bunce, M.; Camera, F.; Corradi, L.; Crespi, F. C. L.; Melon, B.; Farnea, E.; Fioretto, E.; Gottardo, A.; Grente, L.; Hess, H.; Kokalova, Tz.; Korten, W.; Kuşoǧlu, A.; Lenzi, S.; Leoni, S.; Ljungvall, J.; Menegazzo, R.; Michelagnoli, C.; Mijatović, T.; Montagnoli, G.; Montanari, D.; Napoli, D. R.; Podolyák, Zs.; Pollarolo, G.; Recchia, F.; Reiter, P.; Roberts, O. J.; Şahin, E.; Salsac, M.-D.; Scarlassara, F.; Sferrazza, M.; Söderström, P.-A.; Stefanini, A. M.; Szilner, S.; Ur, C. A.; Vogt, A.; Walshe, J.

    2017-06-01

    The neutron-rich nucleus 200Pt is investigated via in-beam γ -ray spectroscopy to study the shape evolution in the neutron-rich platinum isotopes towards the N =126 shell closure. The two-neutron transfer reaction 198Pt(82Se, 80Se)200Pt is used to populate excited states of 200Pt. The Advanced Gamma Ray Tracking Array (AGATA) demonstrator coupled with the PRISMA spectrometer detects γ rays coincident with the 80Se recoils, the binary partner of 200Pt. The binary partner method is applied to extract the γ -ray transitions and build the level scheme of 200Pt. The level at 1884 keV reported by Yates et al. [S. W. Yates, E. M. Baum, E. A. Henry, L. G. Mann, N. Roy, A. Aprahamian, R. A. Meyer, and R. Estep, Phys. Rev. C 37, 1889 (1988)] was confirmed to be at 1882.1 keV and assigned as the (61+) state. An additional γ ray was found and it presumably deexcites the (81+) state. The results are compared with state-of-the-art beyond mean-field calculations, performed for the even-even 190 -204Pt isotopes, revealing that 200Pt marks the transition from the γ -unstable behavior of lighter Pt nuclei towards a more spherical one when approaching the N =126 shell closure.

  7. Design of an ultrahigh vacuum transfer mechanism to interconnect an oxide molecular beam epitaxy growth chamber and an x-ray photoemission spectroscopy analysis system

    Science.gov (United States)

    Rutkowski, M. M.; McNicholas, K. M.; Zeng, Zhaoquan; Brillson, L. J.

    2013-06-01

    We designed a mechanism and the accompanying sample holders to transfer between a VEECO 930 oxide molecular beam epitaxy (MBE) and a PHI Versa Probe X-ray photoemission spectroscopy (XPS) chamber within a multiple station growth, processing, and analysis system through ultrahigh vacuum (UHV). The mechanism consists of four parts: (1) a platen compatible with the MBE growth stage, (2) a platen compatible with the XPS analysis stage, (3) a sample coupon that is transferred between the two platens, and (4) the accompanying UHV transfer line. The mechanism offers a robust design that enables transfer back and forth between the growth chamber and the analysis chamber, and yet is flexible enough to allow transfer between standard sample holders for thin film growth and masked sample holders for making electrical contacts and Schottky junctions, all without breaking vacuum. We used this mechanism to transfer a barium strontium titanate thin film into the XPS analysis chamber and performed XPS measurements before and after exposing the sample to the air. After air exposure, a thin overlayer of carbon was found to form and a significant shift (˜1 eV) in the core level binding energies was observed.

  8. Design of an ultrahigh vacuum transfer mechanism to interconnect an oxide molecular beam epitaxy growth chamber and an x-ray photoemission spectroscopy analysis system.

    Science.gov (United States)

    Rutkowski, M M; McNicholas, K M; Zeng, Zhaoquan; Brillson, L J

    2013-06-01

    We designed a mechanism and the accompanying sample holders to transfer between a VEECO 930 oxide molecular beam epitaxy (MBE) and a PHI Versa Probe X-ray photoemission spectroscopy (XPS) chamber within a multiple station growth, processing, and analysis system through ultrahigh vacuum (UHV). The mechanism consists of four parts: (1) a platen compatible with the MBE growth stage, (2) a platen compatible with the XPS analysis stage, (3) a sample coupon that is transferred between the two platens, and (4) the accompanying UHV transfer line. The mechanism offers a robust design that enables transfer back and forth between the growth chamber and the analysis chamber, and yet is flexible enough to allow transfer between standard sample holders for thin film growth and masked sample holders for making electrical contacts and Schottky junctions, all without breaking vacuum. We used this mechanism to transfer a barium strontium titanate thin film into the XPS analysis chamber and performed XPS measurements before and after exposing the sample to the air. After air exposure, a thin overlayer of carbon was found to form and a significant shift (~1 eV) in the core level binding energies was observed.

  9. FLUORESCENCE LIFETIME DISTRIBUTIONS IN PROTEINS

    OpenAIRE

    ALCALA, JR; Gratton, E; PRENDERGAST, FG

    1987-01-01

    The fluorescence lifetime value of tryptophan residues varies by more than a factor of 100 in different proteins and is determined by several factors, which include solvent exposure and interactions with other elements of the protein matrix. Because of the variety of different elements that can alter the lifetime value and the sensitivity to the particular environment of the tryptophan residue, it is likely that non-unique lifetime values result in protein systems. The emission decay of most ...

  10. Lifetime-weighted photoacoustic imaging

    Science.gov (United States)

    Forbrich, A.; Shao, P.; Shi, W.; Zemp, Roger J.

    2016-12-01

    Photoacoustic (PA) imaging has been utilized to quantify the lifetime profile of exogenous agents using a series of pump-probe pulses with a varying time delay; however, current techniques typically lead to long acquisition times which are sensitive to motion and cause absorption or photobleaching. We introduce a technique called lifetime-weighted imaging, which uses only three laser pulses to preferentially weight signals from chromophores with long lifetimes (including exogenous contrast agents with triplet excited states such as methylene blue and porphyrins) while nulling chromophores with short picosecond- to nanosecond-scale lifetimes (including hemoglobin). This technique detects the PA signal from a probe pulse either with or without a pump pulse. By subtracting the probe-only signal from the pump-present probe signal, we effectively eliminate signals from chromophores with short lifetimes while preserving PA signals from chromophores with long-lifetimes. We demonstrate the oxygen-dependent lifetime of both methylene blue and porphyrin-lipids and demonstrate both ground-state recovery and excited-state lifetime-weighted imaging. Lifetime-weighted PA imaging may have applications in many molecular imaging application including: photodynamic therapy dosimetry guidance and oxygen sensing.

  11. Energy Savings Lifetimes and Persistence

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, Ian M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Schiller, Steven R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Todd, Annika [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Billingsley, Megan A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Goldman, Charles A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Schwartz, Lisa C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-02-01

    This technical brief explains the concepts of energy savings lifetimes and savings persistence and discusses how program administrators use these factors to calculate savings for efficiency measures, programs and portfolios. Savings lifetime is the length of time that one or more energy efficiency measures or activities save energy, and savings persistence is the change in savings throughout the functional life of a given efficiency measure or activity. Savings lifetimes are essential for assessing the lifecycle benefits and cost effectiveness of efficiency activities and for forecasting loads in resource planning. The brief also provides estimates of savings lifetimes derived from a national collection of costs and savings for electric efficiency programs and portfolios.

  12. Copulas Between Wealth and Lifetime

    Institute of Scientific and Technical Information of China (English)

    YE Dongyan

    2009-01-01

    The life insurance industry is very interested in how a person's lifetime is related to his wealth with financial advisors interested in how even a person's portfolio choice affects his lifetime. This paper presents a statistical analysis combined with intuitive relationships between lifetime and wealth. Key properties of this relationship are given and then various copulas are analyzed to see whether they have these properties. Other advantages and disadvantages of these copulas for describing the dependence are stated. The results show that some copulas are not appropriate for relating lifetime and wealth, including the Gaussian family.

  13. 钼(Mo)原子奇宇称能级自然辐射寿命的测量%Natural Radiative Lifetime Measurements of Atoms and Ions in Astronomic Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    蒋红玫; 戴振文

    2012-01-01

    介绍了测量原子(离子)激发态自然辐射寿命的原理方法,并运用激光诱导荧光时间分辨光谱技术和激光烧蚀产生等离子体技术对钼(Mo)原子的5个奇宇称高激发态能级自然辐射寿命进行了测量.%The authors introduced the principles of lifertime measurement, and measured the natual radiative lifetime of Mo atom at 5 odd-parity highly-exited levels by means of the time-resolved laser-induced fluorescence and laser ablation techniques.

  14. Improved Determination of the Neutron Lifetime

    CERN Document Server

    Yue, A T; Gilliam, D M; Greene, G L; Laptev, A B; Nico, J S; Snow, W M; Wietfeldt, F E

    2013-01-01

    The most precise determination of the neutron lifetime using the beam method was completed in 2005 and reported a result of tau_n = (886.3 +/- 1.2 [stat] +/- 3.2 [sys]) s. The dominant uncertainties were attributed to the absolute determination of the fluence of the neutron beam (2.7 s). The fluence was measured with a neutron monitor that counted the neutron-induced charged particles from absorption in a thin, well-characterized 6Li deposit. The detection efficiency of the monitor was calculated from the areal density of the deposit, the detector solid angle, and the ENDF/B-VI 6Li(n,t)4He thermal neutron cross section. In the current work, we have measured the detection efficiency of the same monitor used in the neutron lifetime measurement with a second, totally-absorbing neutron detector. This direct approach does not rely on the 6Li(n,t)4He cross section or any other nuclear data. The detection efficiency is consistent with the value used in 2005 but was measured with a precision of 0.057 %, which represe...

  15. Cosmological constraints on the neutron lifetime

    CERN Document Server

    Salvati, Laura; Consiglio, Rossella; Melchiorri, Alessandro

    2015-01-01

    We derive new constraints on the neutron lifetime based on the recent Planck 2015 observations of temperature and polarization anisotropies of the CMB. Under the assumption of standard Big Bang Nucleosynthesis, we show that Planck data constrains the neutron lifetime to $\\tau_n=(907 \\pm 69) \\, [\\text{s}]$ at $68 \\%$ c.l.. Moreover, by including the direct measurements of primordial Helium abundance of Izotov et al. 2014 and Mucciarelli et al. 2014, we show that cosmological data provide the stringent constraint $\\tau_n=(905.7 \\pm 7.8) \\, [\\text{s}]$. This value is in tension with the most recent experimental value of $\\tau_n^{\\text{bottle}}=(879.6 \\pm 0.8) \\, [\\text{s}]$ provided by the "bottle method" based on Ultra Cold Neutrons, but in agreement with the experimental value of $\\tau_n^{\\text{beam}}=(888.0 \\pm 2.1) \\, [\\text{s}]$ based on the "beam method". Future CMB surveys as COrE+, in combination with a weak lensing survey as EUCLID, could constrain the neutron life time up to a $\\sim 6$ s precision.

  16. The spectroscopy in the atomic vapour

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jai Hyung; Chang, Joon Sung; Jhe, Won Ho [Seoul National University, Seoul (Korea)

    1998-04-01

    As spectroscopies in the atomic vapor, we perform experiments on fluorescence in dense atomic vapor, single color two-photon resonant three photon ionization, production of high temperature oven and its spectroscopic application, atomic trap and cold atomic beam. We observe lengthening of lifetime as atomic density increase and compare this result with Holstein equation. Dependence on pressure an d polarization reveals the result is due to collisions between Yb atom and Ar buffer gas. At high atomic density, self-focusing and conical emission are observed. In two-photon resonant three photon ionization scheme, ionization rate is dependent on polarization. From selection rule, we determined the energy level. At higher energy, asymmetry and broadening of ionization linewidth due to AC Stark effect are observed. As the result of numerical simulation of time evolution in the two-photon transition, distortion of time evolution of density is obtained. For spectroscopy of high-melting-point elements, we design and produce high temperature oven. We observe absorption spectra of high-melting-point elements, Er and Sm. As high temperature nonlinear spectroscopies, we perform conical emission and self-diffraction in Sm vapor. We produce magneto-optical trap system and measure fluorescence from trapped atoms and temperature. By trapping Rb isotopes simultaneously, we perform collision experiment at low temperature. Using hollow mirror system, we trap atoms and produce cold atomic beam. (author). 160 refs., 66 figs., 5 tabs.

  17. Experimental positions and lifetimes of Be-like 1s{sup 2}3lnl'(n=3 to 5) states of O{sup 4+} and Ne{sup 6+} ions investigated by high resolution electron spectroscopy: test of calculations

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-07-01

    Using high resolution electron spectroscopy, positions and lifetimes of many Be-like singlet states of the 1s{sup 2}3lnl' Rydberg series (n = 3 to 5) of oxygen and neon have been measured for the first time. This was achieved by a fitting procedure which takes into account an accurate definition of the post-collisional electron lineshapes. These states are produced after a double electron capture by multicharged ions has occurred in O{sup 6+}(1s{sup 2})+He, H{sub 2} and Ne{sup 8+}(1s{sup 2})+He collisions at about 4 keV/amu collision energy. (orig.)

  18. Lifetime of Mechanical Equipment

    Energy Technology Data Exchange (ETDEWEB)

    Leland, K.

    1999-07-01

    The gas plant at Kaarstoe was built as part of the Statpipe gas transport system and went on stream in 1985. In 1993 another line was routed from the Sleipner field to carry condensate, and the plant was extended accordingly. Today heavy additional supply- and export lines are under construction, and the plant is extended more than ever. The main role of the factory is to separate the raw gas into commercial products and to pump or ship it to the markets. The site covers a large number of well-known mechanical equipment. This presentation deals with piping, mechanical and structural disciplines. The lifetime of mechanical equipment is often difficult to predict as it depends on many factors, and the subject is complex. Mechanical equipment has been kept in-house, which provides detailed knowledge of the stages from a new to a 14 years old plant. The production regularity has always been very high, as required. The standard of the equipment is well kept, support systems are efficient, and human improvisation is extremely valuable.

  19. High spin spectroscopy of near spherical nuclei: Role of intruder orbitals

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharyya, S.; Bhattacharjee, T.; Mukherjee, G. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata - 700064 (India); Chanda, S. [Fakir Chand College, Diamond Herbour, West Bengal (India); Banerjee, D.; Das, S. K.; Guin, R. [Radiochemistry Division, Variable Energy Cyclotron Centre, BARC, Kolkata - 700064 (India); Gupta, S. Das [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata - 700064, India and Saha Institute of Nuclear Physics, Kolkata-700064 (India); Pai, H. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata - 700064, India and Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstrasse 9, 64289 Darmstadt (Germany)

    2014-08-14

    High spin states of nuclei in the vicinity of neutron shell closure N = 82 and proton shell closure Z = 82 have been studied using the Clovere Ge detectors of Indian National Gamma Array. The shape driving effects of proton and neutron unique parity intruder orbitals for the structure of nuclei around the above shell closures have been investigated using light and heavy ion beams. Lifetime measurements of excited states in {sup 139}Pr have been done using pulsed-beam-γ coincidence technique. The prompt spectroscopy of {sup 207}Rn has been extended beyond the 181μs 13/2{sup +} isomer. Neutron-rich nuclei around {sup 132}Sn have been produced from proton induced fission of {sup 235}U and lifetime measurement of low-lying states of odd-odd {sup 132}I have been performed from offline decay.

  20. Lifetime Improvement by Battery Scheduling

    NARCIS (Netherlands)

    Jongerden, M.R.; Schmitt, Jens B.; Haverkort, Boudewijn R.H.M.

    2012-01-01

    The use of mobile devices is often limited by the lifetime of their batteries. For devices that have multiple batteries or that have the option to connect an extra battery, battery scheduling, thereby exploiting the recovery properties of the batteries, can help to extend the system lifetime. Due to

  1. Lifetime improvement by battery scheduling

    NARCIS (Netherlands)

    Jongerden, M.R.; Haverkort, Boudewijn R.H.M.

    2011-01-01

    The use of mobile devices is often limited by the lifetime of its battery. For devices that have multiple batteries or that have the option to connect an extra battery, battery scheduling, thereby exploiting the recovery properties of the batteries, can help to extend the system lifetime. Due to the

  2. Lifetime Improvement by Battery Scheduling

    NARCIS (Netherlands)

    Jongerden, M.R.; Schmitt, Jens B.; Haverkort, Boudewijn R.H.M.

    The use of mobile devices is often limited by the lifetime of their batteries. For devices that have multiple batteries or that have the option to connect an extra battery, battery scheduling, thereby exploiting the recovery properties of the batteries, can help to extend the system lifetime. Due to

  3. Lifetime improvement by battery scheduling

    NARCIS (Netherlands)

    Jongerden, M.R.; Haverkort, Boudewijn R.H.M.

    The use of mobile devices is often limited by the lifetime of its battery. For devices that have multiple batteries or that have the option to connect an extra battery, battery scheduling, thereby exploiting the recovery properties of the batteries, can help to extend the system lifetime. Due to the

  4. Photon emission spectroscopy of ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Nystroem, B.

    1995-10-01

    Emission cross sections for the 1snp{sup 1}P{sub 1}-levels have been measured by photon emission spectroscopy for the collision systems He{sup +} + He at 10 keV and He{sup 2+} + He at 10-35 keV. Photon spectra of Krypton (Kr VIII) and Xenon (Xe V - IX) have also been obtained using 10q keV beams of Kr{sup q+} (q=7-9) and Xe{sup q+} (q=5-9) colliding with Helium and Argon. The Lifetimes of 3p{sup 2}P-levels in Na-like Nb are reported together with lifetime for the 3s3p{sup 3}P{sub 1}-level in Mg-like Ni, Kr, Y, Zr and Nb where this level has an intercombination transition to the ground state. 45 refs, 20 figs.

  5. Investigation of the reaction of hydroxy and carbon monoxide to form hydrogen and carbon dioxide by Photoelectron-Photofragment Coincidence spectroscopy in a cryogenic ion beam trap

    Science.gov (United States)

    Johnson, Christopher Joseph

    2011-12-01

    The HOCO radical plays a crucial role in a wide variety of chemical processes, including atmospheric CO2 regulation and combustion chemistry, as an intermediate in the elementary reaction OH + CO → H + CO2 . However, scant information exists on this species due to the difficulties in studying it. Previous photoelectron-photofragment coincidence (PPC) studies performed in this laboratory have identified key processes occurring on the HOCO potential energy surface, but are complicated by the presence of internal excitation in the precursor anions, leading to uncertainties in product energies and dynamics. To address this, a new instrument has been constructed which incorporates a cryogenically cooled linear electrostatic storage device, providing a cold source of anions for dissociative photodetachment studies by PPC spectroscopy. The enhanced resolution and well-characterized energetics provided by this instrument have allowed the fundamental energetics and processes occurring on the HOCO potential energy surface to be studied in unprecedented detail. New data shows unambiguous confirmation of the presence of tunneling in the reaction HOCO → H + CO2. Careful study of this product channel has led to the generation a model one-dimensional potential barrier describing this process directly from experimental tunneling data, and tunneling lifetimes over a range of relevant internal energies to be predicted. High resolution photodetachment experiments provide a reassignment of the electron affinities of both cis- and trans-HOCO and the determination of several normal mode frequencies not previously measured in the gas phase, each with the support of high-level ab initio quantum chemical calculations. Further details on the previously-unknown isomer well depths and the process of isomerization have been extracted using this information. Finally, nonresonant two-photon photodetachment studies of NO2 -, a species with striking electronic structure similarities to HOCO

  6. Laser Spectroscopy of Antiprotonic Helium Atoms

    CERN Multimedia

    2002-01-01

    %PS205 %title\\\\ \\\\Following the discovery of metastable antiprotonic helium atoms ($\\overline{p}He^{+} $) at KEK in 1991, systematic studies of their properties were made at LEAR from 1991 to 1996. In the first two years the lifetime of $\\overline{p}He^{+}$ in liquid and gaseous helium at various temperatures and pressures was measured and the effect of foreign gases on the lifetime of these atoms was investigated. Effects were also discovered which gave the antiproton a 14\\% longer lifetime in $^4$He than in $^3$He, and resulted in important differences in the shape of the annihilation time spectra in the two isotopes.\\\\ \\\\Since 1993 laser spectroscopy of the metastable $\\overline{p}He^{+}$ atoms became the main focus of PS205. Transitions were stimulated between metastable and non-metastable states of the $\\overline{p}He^{+}$ atom by firing a pulsed dye laser beam into the helium target every time an identified metastable atom was present (Figure 1). If the laser frequency matched the transition energy, the...

  7. Resolution of heterogeneous fluorescence emission signals and decay lifetime measurement on fluorochrome-labeled cells by phase-sensitive FCM

    Energy Technology Data Exchange (ETDEWEB)

    Steinkamp, J.A.; Crissman, H.A.

    1993-02-01

    A phase-sensitive flow cytometer has been developed to resolve signals from heterogeneous fluorescence emission spectra and quantify fluorescence decay times on cells labeled with fluorescent dyes. This instrument combines flow cytometry (FCM) and fluorescence spectroscopy measurement principles to provide unique capabilities for making phase-resolved measurements on single cells in flow, while preserving conventional FCM measurement capabilities. Stained cells are analyzed as they pass through an intensity-modulated (sinusoid) laser excitation beam. Fluorescence is measured orthogonally using a s barrier filter to block scattered laser excitation light, and a photomultiplier tube detector output signals, which are shifted in phase from a reference signal and amplitude demodulated, are processed by phase-sensitive detection electronics to resolve signals from heterogeneous emissions and quantify decay lifetimes directly. The output signals are displayed as frequency distribution histograms and bivariate diagrams using a computer-based data acquisition system. Results have demonstrated signal phase shift, amplitude demodulation, and average measurement of fluorescence lifetimes on stained cells; a detection limit threshold of 300 to 500 fluorescein isothiocyanate (FITC); fluorescence measurement precision of 1.3% on alignment fluorospheres and 3.4% on propidium iodide (PI)-stained cells; the resolution of PI and FITC signals from cells stainedin combination with PI and FITC, based on differences in their decay lifetimes; and the ability to measure single decay nines by the two-phase, phase comparator, method.

  8. Resolution of heterogeneous fluorescence emission signals and decay lifetime measurement on fluorochrome-labeled cells by phase-sensitive FCM

    Energy Technology Data Exchange (ETDEWEB)

    Steinkamp, J.A.; Crissman, H.A.

    1993-01-01

    A phase-sensitive flow cytometer has been developed to resolve signals from heterogeneous fluorescence emission spectra and quantify fluorescence decay times on cells labeled with fluorescent dyes. This instrument combines flow cytometry (FCM) and fluorescence spectroscopy measurement principles to provide unique capabilities for making phase-resolved measurements on single cells in flow, while preserving conventional FCM measurement capabilities. Stained cells are analyzed as they pass through an intensity-modulated (sinusoid) laser excitation beam. Fluorescence is measured orthogonally using a s barrier filter to block scattered laser excitation light, and a photomultiplier tube detector output signals, which are shifted in phase from a reference signal and amplitude demodulated, are processed by phase-sensitive detection electronics to resolve signals from heterogeneous emissions and quantify decay lifetimes directly. The output signals are displayed as frequency distribution histograms and bivariate diagrams using a computer-based data acquisition system. Results have demonstrated signal phase shift, amplitude demodulation, and average measurement of fluorescence lifetimes on stained cells; a detection limit threshold of 300 to 500 fluorescein isothiocyanate (FITC); fluorescence measurement precision of 1.3% on alignment fluorospheres and 3.4% on propidium iodide (PI)-stained cells; the resolution of PI and FITC signals from cells stainedin combination with PI and FITC, based on differences in their decay lifetimes; and the ability to measure single decay nines by the two-phase, phase comparator, method.

  9. Comparative investigation of laser-induced breakdown spectroscopy in bulk water using 532- and 1064-nm lasers

    Science.gov (United States)

    Tian, Ye; Xue, Boyang; Song, Jiaojian; Lu, Yuan; Li, Ying; Zheng, Ronger

    2017-07-01

    The influence of laser wavelength on the characteristics of laser-induced breakdown spectroscopy (LIBS) in bulk water was investigated by using 532- and 1064-nm lasers. We demonstrated that higher laser energy does not lead to higher LIBS signals because of the strong plasma shielding occurring at high laser energies, as shown by the spectroscopic and fast imaging results in this work. At threshold energies of 100% breakdown probability, the 1064 nm beam could induce a plasma with higher electron density and temperature than the 532 nm beam, which leads to higher signal-to-noise ratios and longer lifetimes of the emission lines.

  10. An accurate test of calculated positions and lifetimes for Ne{sup 6+}(1s{sup 2}3lnl{sup '}) {sup 1}L states (n=3 and 4) using a high-resolution electron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, A. E-mail: abm@irsamc.ups-tlse.fr; Moretto-Capelle, P.; Bordenave-Montesquieu, D

    2003-05-01

    An accurate test of available calculations for the autoionizing doubly excited states belonging to the Be-like 1s{sup 2}3lnl{sup '} Rydberg series of neon (positions and lifetimes) is presented in this short communication. These theoretical data are used to calculate electron line shapes which are compared, through a fitting procedure, with a high-resolution electron spectrum measured in Ne{sup 8+}(1s{sup 2}) + He collisional system, at 80 keV collision energy and 13.1 deg. observation angle. Present tests concern the n=3 and n=4 singlet states. It is found that some of these calculations suffer from large discrepancies with experiment and do not allow a description of the electron spectrum. A quantitative comparison of measured and calculated post-collisional Coulomb interaction-shifted line positions is also given and briefly discussed; for one theoretical data set, the agreement with experiment is found to be generally within {+-}50 meV; in contrast agreement with other data often considerably scatters within {+-}500 meV and sometimes more.

  11. Set-up for lifetime measurements with the DSA method

    Energy Technology Data Exchange (ETDEWEB)

    Avrigeanu, V.; Bucurescu, D.; Ivascu, M.; Osvath, E.; Popescu, D.; Stog, O.

    1975-01-01

    A set-up for the measurement of short nuclear lifetimes at the IAP U-120 cyclotron, by means of the Doppler shift attenuation method (DSAM) is described. A 100 mm diameter reaction chamber is used, with a transparent window which allows visualization of the beam spot on the target. The electronic block scheme is discussed. As a test measurement for this set-up the determination of the lifetime of the first 2/sup +/ state in /sup 30/Si by means of the /sup 27/Al(..cap alpha..,p..gamma..)/sup 30/Si reaction is presented. 5 figures.

  12. Measurement of Metastable Lifetimes of Highly-Charged Ions

    Science.gov (United States)

    Smith, Steven J.; Chutjian, A.; Lozano, J.

    2002-01-01

    The present work is part of a series of measurements of metastable lifetimes of highly-charged ions (HCIs) which contribute to optical absorption, emission and energy balance in the Interstellar Medium (ISM), stellar atmospheres, etc. Measurements were carried out using the 14-GHz electron cyclotron resonance ion source (ECRIS) at the JPL HCI facility. The ECR provides useful currents of charge states such as C(sup(1-6)+), Mg(sup(1-6)+) and Fe(sup(1-17)+). In this work the HCI beam is focused into a Kingdon electrostatic ion trap for measuring lifetimes via optical decays.

  13. Preliminary Ξc+ Lifetime Measurement from SELEX

    Science.gov (United States)

    Akgun, U.; Selex Collaboration

    2007-05-01

    We report the results of a new Ξc+ lifetime measurement from hadroproduction data taken by the SELEX (E781) experiment. Fermilab charged hyperon beam ( Σ, π and p) at 600 GeV is used to produce charm particles in Cu and diamond targets. This measurement was made using decays into the Ξc+→Ξππ, Ξc+→pKπ, and Ξc+→ΣKπ modes. We used binned maximum likelihood method and 301 ± 31 events yield a lifetime of 430 ± 22 ± 9 fs.

  14. Lifetime costs of cerebral palsy

    DEFF Research Database (Denmark)

    Kruse, Marie; Michelsen, Susan Ishøy; Flachs, Esben Meulengracht

    2009-01-01

    This study quantified the lifetime costs of cerebral palsy (CP) in a register-based setting. It was the first study outside the US to assess the lifetime costs of CP. The lifetime costs attributable to CP were divided into three categories: health care costs, productivity costs, and social costs....... The population analyzed was retrieved from the Danish Cerebral Palsy Register, which covers the eastern part of the country and has registered about half of the Danish population of individuals with CP since 1950. For this study we analyzed 2367 individuals with CP, who were born in 1930 to 2000 and were alive...

  15. SPIDER beam dump as diagnostic of the particle beam

    Science.gov (United States)

    Zaupa, M.; Dalla Palma, M.; Sartori, E.; Brombin, M.; Pasqualotto, R.

    2016-11-01

    The beam power produced by the negative ion source for the production of ion of deuterium extracted from RF plasma is mainly absorbed by the beam dump component which has been designed also for measuring the temperatures on the dumping panels for beam diagnostics. A finite element code has been developed to characterize, by thermo-hydraulic analysis, the sensitivity of the beam dump to the different beam parameters. The results prove the capability of diagnosing the beam divergence and the horizontal misalignment, while the entity of the halo fraction appears hardly detectable without considering the other foreseen diagnostics like tomography and beam emission spectroscopy.

  16. SPIDER beam dump as diagnostic of the particle beam

    Energy Technology Data Exchange (ETDEWEB)

    Zaupa, M., E-mail: matteo.zaupa@igi.cnr.it; Sartori, E. [Università degli Studi di Padova, Via 8 Febbraio 2, Padova 35122 (Italy); Consorzio RFX, Corso Stati Uniti 4, Padova 35127 (Italy); Dalla Palma, M.; Brombin, M.; Pasqualotto, R. [Consorzio RFX, Corso Stati Uniti 4, Padova 35127 (Italy)

    2016-11-15

    The beam power produced by the negative ion source for the production of ion of deuterium extracted from RF plasma is mainly absorbed by the beam dump component which has been designed also for measuring the temperatures on the dumping panels for beam diagnostics. A finite element code has been developed to characterize, by thermo-hydraulic analysis, the sensitivity of the beam dump to the different beam parameters. The results prove the capability of diagnosing the beam divergence and the horizontal misalignment, while the entity of the halo fraction appears hardly detectable without considering the other foreseen diagnostics like tomography and beam emission spectroscopy.

  17. Beam Loss and Beam Shape at the LHC Collimators

    CERN Document Server

    Burkart, Florian

    In this master thesis the beam loss and the beam shape at the LHC collimators was measured, analysed, presented and discussed. Beginning with a short introduction of the LHC, the experiments, the supercon- ducting magnet system, the basics on linear beam dynamics and a describtion of the LHC collimation system are given. This is followed by the presentation of the performance of the LHC collimation sys- tem during 2011. A method to convert the Beam Loss Monitor signal in Gy/s to a proton beam loss rate will be introduced. Also the beam lifetime during the proton physics runs in 2011 will be presented and discussed. Finally, the shape of the LHC beams is analysed by using data obtained by scraping the beam at the LHC primary collimators.

  18. Radiative lifetimes of odd-parity levels in Nb I

    Science.gov (United States)

    Mukund, Sheo; Bhattacharyya, Soumen; Yarlagadda, Suresh; Nakhate, S. G.

    2015-11-01

    Radiative lifetimes are reported for 37 odd-parity energy levels of neutral niobium (Nb I), out of which 33 have been measured for the first time. The levels belong to electronic configurations 4d35s5p and 4d45p between 18,790 and 35,730 cm-1. The time-resolved laser-induced fluorescence spectroscopy technique was employed. The Nb atoms were generated in a free-jet by laser vaporization of niobium metal. Lifetime values reported in this work fall in the range 12-340 ns and are accurate to ±10%.

  19. Radiation hardness and lifetime studies of the VCSELs for the ATLAS SemiConductor Tracker

    CERN Document Server

    Teng, P K; Chu, M L; Duh, T S; Gregor, I M; Hou, L S; Lee, S C; Song, P S; Su, D S

    2003-01-01

    Studies have been performed on the radiation hardness of the type of VCSELs**2 Vertical Cavity Surface Emitting Lasers. that will be used in the ATLAS SemicConductor Tracker. The measurements were made using 30 MeV proton beams, 24 GeV/c proton beams and a gamma source. The lifetime of the devices after irradiation was studied.

  20. Diamond: a material for laser spectroscopy

    Science.gov (United States)

    Castex, M. C.; Riedel, D.; Museur, L.; Chardonnet, Christian; Gicquel, Alix; Foulon, Francois; Borel, C.; Bergonzo, P.; Jany, C.

    1998-10-01

    Diamond polycrystalline films synthesized by chemical vapor deposition techniques present interesting feature for laser spectroscopy due to several advantages arising from their optical, electronic, thermal and mechanical properties. Their wide transmission band from the far IR to the UV make them attractive as optical devices for high-power laser beam. Moreover, with a wide band gap, a short carrier lifetime and a high damage threshold, diamond is an ideal semiconductor material for the fabrication of fast and solar blind VUV detectors. We report here results of laser studies performed with tow different objectives. With use of a pulsed VUV laser at 125 nm we have determined the photoconductive response of polycrystalline diamond detectors. With a CO2 laser we have investigated the polarization properties of auto-supported films having thicknesses smaller than the wavelength.

  1. Increasing precision of lifetime determination in fluorescence lifetime imaging

    Science.gov (United States)

    Chang, Ching-Wei; Mycek, Mary-Ann

    2010-02-01

    The interest in fluorescence lifetime imaging microscopy (FLIM) is increasing, as commercial FLIM modules become available for confocal and multi-photon microscopy. In biological FLIM applications, low fluorescence signals from samples can be a challenge, and this causes poor precision in lifetime. In this study, for the first time, we applied wavelet-based denoising methods in time-domain FLIM, and compared them with our previously developed total variation (TV) denoising methods. They were first tested using artificial FLIM images. We then applied them to lowlight live-cell images. The results demonstrated that our TV methods could improve lifetime precision multi-fold in FLIM images and preserve the overall lifetime and pre-exponential term values when improving local lifetime fitting, while wavelet-based methods were faster. The results here can enhance the precision of FLIM, especially for low-light and / or fast video-rate imaging, to improve current and rapidly emerging new applications of FLIM such as live-cell, in vivo whole-animal, or endoscopic imaging.

  2. Laser-rf double-resonance spectroscopy in a storage ring

    Science.gov (United States)

    Kristensen, M.; Hangst, J. S.; Jessen, P. S.; Nielsen, J. S.; Poulsen, O.; Shi, P.

    1992-10-01

    Laser-rf double-resonance spectroscopy of the hyperfine transition between F''=0 and F'=1 in the metastable 3S1 state of 6Li+ was performed in 100-keV beam in the storage ring ASTRID. High efficiency of optical pumping was demonstrated for complex pumping schemes. A broadband (dc-6 GHz) rf device was designed and used for rf spectroscopy in the storage ring. The possibility of obtaining coherent rf signals (Ramsey fringes) from successive interactions with the same field was investigated. Important limitations for the coherences due to magnetic-field inhomogeneities were observed. These led to randomization of the atomic polarization during only one turn in the storage ring and completely prevented observation of Ramsey fringes. This situation is different from the case of fundamental particles in a storage ring, where the polarization may be preserved for many round-trips. Limits were put on the demands to beam quality, beam positioning, and magnetic-field quality to overcome the problem. The effects of the rf device on the external degrees of freedom of the ion beam were investigated. Its small aperture substantially reduced the beam lifetime, and at very low rf frequencies the electric field in the rf device was able to excite external transverse resonances in the beam.

  3. Neutron Transport Simulations for NIST Neutron Lifetime Experiment

    Science.gov (United States)

    Li, Fangchen; BL2 Collaboration Collaboration

    2016-09-01

    Neutrons in stable nuclei can exist forever; a free neutron lasts for about 15 minutes on average before it beta decays to a proton, an electron, and an antineutrino. Precision measurements of the neutron lifetime test the validity of weak interaction theory and provide input into the theory of the evolution of light elements in the early universe. There are two predominant ways of measuring the neutron lifetime: the bottle method and the beam method. The bottle method measures decays of ultracold neutrons that are stored in a bottle. The beam method measures decay protons in a beam of cold neutrons of known flux. An improved beam experiment is being prepared at the National Institute of Science and Technology (Gaithersburg, MD) with the goal of reducing statistical and systematic uncertainties to the level of 1 s. The purpose of my studies was to develop computer simulations of neutron transport to determine the beam collimation and study the neutron distribution's effect on systematic effects for the experiment, such as the solid angle of the neutron flux monitor. The motivation for the experiment and the results of this work will be presented. This work was supported, in part, by a Grant to Gettysburg College from the Howard Hughes Medical Institute through the Precollege and Undergraduate Science Education Program.

  4. In vivo fluorescence lifetime tomography

    Science.gov (United States)

    Nothdurft, Ralph E.; Patwardhan, Sachin V.; Akers, Walter; Ye, Yunpeng; Achilefu, Samuel; Culver, Joseph P.

    2009-03-01

    Local molecular and physiological processes can be imaged in vivo through perturbations in the fluorescence lifetime (FLT) of optical imaging agents. In addition to providing functional information, FLT methods can quantify specific molecular events and multiplex diagnostic and prognostic information. We have developed a fluorescence lifetime diffuse optical tomography (DOT) system for in vivo preclinical imaging. Data is captured using a time-resolved intensified charge coupled device (ICCD) system to measure fluorescence excitation and emission in the time domain. Data is then converted to the frequency domain, and we simultaneously reconstruct images of yield and lifetime using an extension to the normalized Born approach. By using differential phase measurements, we demonstrate DOT imaging of short lifetimes (from 350 ps) with high precision (+/-5 ps). Furthermore, this system retains the efficiency, speed, and flexibility of transmission geometry DOT. We demonstrate feasibility of FLT-DOT through a progressive series of experiments. Lifetime range and repeatability are first measured in phantoms. Imaging of subcutaneous implants then verifies the FLT-DOT approach in vivo in the presence of inhomogeneous optical properties. Use in a common research scenario is ultimately demonstrated by imaging accumulation of a targeted near-infrared (NIR) fluorescent-labeled peptide probe (cypate-RGD) in a mouse with a subcutaneous tumor.

  5. Stochastic Boundary, Diffusion, Emittance Growth and Lifetime calculation for the RHIC e-lens

    Energy Technology Data Exchange (ETDEWEB)

    Abreu,N.P.; Fischer, W.; Luo, Y.; Robert-Demolaize, G.

    2009-01-20

    To compensate the large tune shift and tune spread generated by the head-on beam-beam interactions in polarized proton operation in the Relativistic Heavy Ion Collider (RHIC), a low energy electron beam with proper Gaussian transverse profiles was proposed to collide head-on with the proton beam. In this article, using a modified version of SixTrack [1], we investigate stability of the single particle in the presence of head-on beam-beam compensation. The Lyapunov exponent and action diffusion are calculated and compared between the cases without and with beam-beam compensation for two different working points and various bunch intensities. Using the action diffusion results the emittance growth rate and lifetime of the proton beam is also estimated for the different scenarios.

  6. Direct Measurements of the Lifetime of Heavy Hypernuclei

    CERN Document Server

    Qiu, X; Margaryan, A; Achenbach, P; Ahmidouch, A; Albayrak, I; Androic, D; Asaturyan, A; Asaturyan, R; Ates, O; Badui, R; Baturin, P; Boeglin, W; Bono, J; Brash, E; Carter, P; Chen, C; Chen, X; Chiba, A; Christy, E; Dalton, M M; Danagoulian, S; De Leo, R; Doi, D; Elaasar, M; Ent, R; Fenker, H; Fujii, Y; Furic, M; Gabrielyan, M; Gan, L; Garibaldi, F; Gaskell, D; Gasparian, A; Gogami, T; Hashimoto, O; Horn, T; Hu, B; Hungerford, E V; Jones, M; Kanda, H; Kaneta, M; Kawai, M; Kawama, D; Khanal, H; Kohl, M; Liyanage, A; Luo, W; Maeda, K; Markowitz, P; Maruta, T; Matsumura, A; Maxwell, V; Mkrtchyan, A; Mkrtchyan, H; Nagao, S; Nakamura, S N; Narayan, A; Neville, C; Niculescu, G; Niculescu, M I; Nunez, A; Nuruzzaman,; Okayasu, Y; Petkovic, T; Pochodzalla, J; Reinhold, J; Rodriguez, V M; Samanta, C; Sawatzky, B; Seva, T; Shichijo, A; Tadevosyan, V; Taniya, N; Tsukada, K; Veilleux, M; Vulcan, W; Wesselmann, F R; Wood, S A; Ya, L; Yamamoto, T; Ye, Z; Yokota, K; Yuan, L; Zhamkochyan, S; Zhu, L

    2012-01-01

    The lifetime of a Lambda particle embedded in a nucleus (hypernucleus) decreases from that of free Lambda decay due to the opening of the Lambda N to NN weak decay channel. However, it is generally believed that the lifetime of a hypernucleus attains a constant value (saturation) for medium to heavy hypernuclear masses, yet this hypothesis has been difficult to verify. The present paper reports a direct measurement of the lifetime of medium-heavy hypernuclei produced with a photon-beam from Fe, Cu, Ag, and Bi targets. The recoiling hypernuclei were detected by a fission fragment detector using low-pressure multi-wire proportional chambers. The experiment agrees remarkably well with the only previously-measured single-species heavy-hypernucleus lifetime, that of Fe56_Lambda at KEK, and has significantly higher precision. The experiment disagrees with the measured lifetime of an unknown combination of heavy hypernuclei with 180

  7. UV fluorescence lifetime modification by aluminum and magnesium nanoapertures

    Science.gov (United States)

    Wang, Yunshan; Jiao, Xiaojin; Peterson, Eric M.; Harris, Joel M.; Appusamy, Kanagasundar; Guruswamy, Sivaraman; Blair, Steve

    2016-09-01

    Ultra-violet (UV) fluorescence lifetime modification by aluminum (Al) and magnesium (Mg) nanoapertures are reported in this manuscript. Nanoapertures with diameter ranging from 30nm to 90nm are fabricated using focused ion beam (FIB). Largest lifetime reduction are observed for apertures with smallest diameters and undercuts into glass substrate. For Al nanoapertures, largest lifetime reduction is 5.30×, larger than perviously reported 3.50×.1 For Mg nanoapertures, largest lifetime reduction is 6.90×, which is the largest lifetime reduction of UV fluorescence dye reported so far in literature. The dependence of count rate per molecule (CRM) on aperture size and undercut is also investigated, revealing that CRM increases with increasing undercut, however, the CRM is small (less than 2) for the entire range of aperture size and undercut we investigated. FDTD simulation were conducted and in order to favorably compare experimental results with simulated results, it is critical to take into account the exact shape and material properties of the nano aperture. Simulation results revealed the fundamental difference between Al and Mg nano aperture under 266nm illumination-Mg nano aperture presents a waveguide mode in which the maximum field enhancement and Purcell factor is within the nano aperture instead of on the surface which is the case for Al nano aperture.

  8. RADIATIVE LIFETIMES OF V I AND V II

    Energy Technology Data Exchange (ETDEWEB)

    Den Hartog, E. A.; Lawler, J. E.; Wood, M. P., E-mail: eadenhar@wisc.edu, E-mail: jelawler@wisc.edu, E-mail: mpwood@wisc.edu [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States)

    2014-11-01

    New radiative lifetimes are reported for 168 levels of V I ranging in energy from 18086 cm{sup –1} to 47702 cm{sup –1}, and for 31 levels of V II ranging in energy from 34593 cm{sup –1} to 47420 cm{sup –1}. These lifetimes are measured using time-resolved laser-induced fluorescence on a slow atomic/ionic beam as part of an ongoing study of the radiative properties of the iron group elements. All but two of the V II lifetimes have been measured before using modern laser-based methods, but a large fraction of the V I lifetimes are reported here for the first time. Comparison to earlier measurements is discussed. These new lifetimes are, for the most part, accurate to ±5%. They will be combined with branching fraction measurements to produce a large set of transition probabilities for V I and V II which are needed by the astrophysics community for stellar abundance determinations.

  9. Effect of Copper on the Carrier Lifetime in Black Silicon

    DEFF Research Database (Denmark)

    Porte, Henrik; Turchinovich, Dmitry; Persheyev, Saydulla;

    2011-01-01

    Black silicon is produced by laser annealing of a-Si:H films. During annealing, silicon microstructures are formed on the surface. We use time-resolved terahertz spectroscopy to study the photoconductivity dynamics in black silicon. We find that when a copper film is deposited on top of the a-Si:......-Si:H layer prior to laser annealing, the carrier lifetime of black silicon is significantly reduced....

  10. Progressing towards more quantitative analytical pyrolysis of soil organic matter using molecular beam mass spectroscopy of whole soils and added standards

    Energy Technology Data Exchange (ETDEWEB)

    Haddix, Michelle L.; Magrini-Bair, Kim; Evans, Robert J.; Conant, Richard T.; Wallenstein, Matthew D.; Morris, Sherri J.; Calderón, Francisco; Paul, Eldor A.

    2016-12-01

    Soil organic matter (SOM) is extremely complex. It is composed of hundreds of different organic substances and it has been difficult to quantify these diverse substances in a dynamic-ecosystem functioning standpoint. Analytical pyrolysis has been used to compare chemical differences between soils, but its ability to measure the absolute amount of a specific compound in the soil is still in question. Our objective was to assess whether utilizing pyrolysis-molecular beam mass spectroscopy (py-MBMS) to define the signature of known reference compounds (adenine, indole, palmitic acid, etc.) and biological samples (chitin, fungi, cellulose, etc.) separately and when added to whole soils it was possible to make py-MBMS more quantitative. Reference compounds, spanning a wide variety of compound categories, and biological samples, expected to be present in SOM, were added to three soils from Colorado, Ohio, and Massachusetts that have varying total C, % clay, and clay type. Py-MBMS, a rapid analysis technique originally developed to analyze complex biomolecules, flash pyrolyzes soil organic matter to form products that are often considered characteristic of the original molecular structure. Samples were pyrolyzed at 550 degrees C by py-MBMS. All samples were weighed and %C and %N determined both before and after pyrolysis to evaluate mass loss, C loss, and N loss for the samples.An average relationship of r2 = 0.76 (P = 0.005) was found for the amount of cellulose added to soil at 25, 50, and 100% of soil C relative to the ion intensity of select mass/charge of the compound.There was a relationship of r2 = 0.93 (P < 0.001) for the amount of indole added to soil at 25, 50, and 100% of soil C and the ion intensity of the associated mass variables (mass/charge). Comparing spectra of pure compounds with the spectra of the compounds added to soil and isolated clay showed that interference could occur based on soil type and compound with the Massachusetts soil with high C (55

  11. Antihydrogen Experiment Gravity Interferometry Spectroscopy

    CERN Multimedia

    Tietje, I C; Trezzi, D; Dassa, L; Rienacker, B; Khalidova, O; Ferrari, G; Krasnicky, D; Perini, D; Cerchiari, G; Belov, A; Boscolo, I; Sacerdoti, M G; Ferragut, R O; Nedelec, P; Testera, G; Hinterberger, A; Al-qaradawi, I; Malbrunot, C L S; Brusa, R S; Prelz, F; Manuzio, G; Riccardi, C; Fontana, A; Genova, P; Haider, S; Haug, F; Turbabin, A; Castelli, F; Lagomarsino, V E; Doser, M; Penasa, L; Gninenko, S; Cataneo, F; Zenoni, A; Cabaret, L; Comparat, D P; Zmeskal, J; Scampoli, P; Nesteruk, K P; Dudarev, A; Kellerbauer, A G; Mariazzi, S; Fesel, J V; Carraro, C; Zavatarelli, S M

    The AEGIS experiment (Antihydrogen Experiment: Gravity, Interferometry, Spectroscopy) has the aim of carrying out the first measurement of the gravitational interaction of antimatter to a precision of 1%, by applying techniques from atomic physics, laser spectroscopy and interferometry to a beam of antihydrogen atoms. A further goal of the experiment is to carry out spectroscopy of the antihydrogen atoms in flight.

  12. Positron lifetime in polycrystalline gadolinium

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, A.M.; Serna, J. (Universidad Complutense de Madrid (Spain). Dept. de Fisica del Estado Solido)

    1984-06-16

    Positron lifetimes are measured on polycrystalline gadolinium between 15 and 25 /sup 0/C taking into account the microstructure of the specimens, especially the grain sizes of untreated or annealed sheets. Results show the existence of a trapping effect of positrons in Gd due to different trapping centers such as point defects, dislocations, grain boundaries, and other defects.

  13. Measurement of Charm Meson Lifetimes

    Energy Technology Data Exchange (ETDEWEB)

    Bonvicini, G.; Cinabro, D.; Greene, R.; Perera, L.P.; Zhou, G.J. [Wayne State University, Detroit, Michigan 48202 (United States); Chan, S.; Eigen, G.; Lipeles, E.; Schmidtler, M.; Shapiro, A.; Sun, W.M.; Urheim, J.; Weinstein, A.J.; Wuerthwein, F. [California Institute of Technology, Pasadena, California 91125 (United States); Jaffe, D.E.; Masek, G.; Paar, H.P.; Potter, E.M.; Prell, S.; Sharma, V. [University of California, San Diego, La Jolla, California 92093 (United States); Asner, D.M.; Eppich, A.; Gronberg, J.; Hill, T.S.; Korte, C.M.; Lange, D.J.; Morrison, R.J.; Nelson, H.N.; Nelson, T.K.; Roberts, D.; Tajima, H. [University of California, Santa Barbara, California 93106 (United States); Behrens, B.H.; Ford, W.T.; Gritsan, A.; Krieg, H.; Roy, J.; Smith, J.G. [University of Colorado, Boulder, Colorado 80309-0390 (United States); Alexander, J.P.; Baker, R.; Bebek, C.; Berger, B.E.; Berkelman, K.; Boisvert, V.; Cassel, D.G.; Crowcroft, D.S.; Dickson, M.; von Dombrowski, S.; Drell, P.S.; Dumas, D.J.; Ecklund, K.M.; Ehrlich, R.; Foland, A.D.; Gaidarev, P.; Gibbons, L.; Gittelman, B.; Gray, S.W.; Hartill, D.L.; Heltsley, B.K.; Henderson, S.; Hopman, P.I.; Katayama, N.; Kreinick, D.L.; Lee, T.; Liu, Y.; Meyer, T.O.; Mistry, N.B.; Ng, C.R.; Nordberg, E.; Ogg, M.; Patterson, J.R.; Peterson, D.; Riley, D.; Soffer, A.; Thayer, J.G.; Thies, P.G.; Valant-Spaight, B.; Warburton, A.; Ward, C. [Cornell University, Ithaca, New York 14853 (United States); Athanas, M.; Avery, P.; Jones, C.D.; Lohner, M.; Prescott, C.; Rubiera, A.I.; Yelton, J.; Zheng, J. [University of Florida, Gainesville, Florida 32611 (United States); Brandenburg, G.; Briere, R.A.; Ershov, A.; Gao, Y.S.; Kim, D.Y.; Wilson, R. [Harvard University, Cambridge, Massachusetts 02138 (United States); Browder, T.E.; Li, Y.; Rodriguez, J.L.; Yamamoto, H. [University of Hawaii at Manoa, Honolulu, Hawaii 96822 (United States); Bergfeld, T.; Eisenstein, B.I.; Ernst, J.; Gladding, G.E.; Gollin, G.D; and others

    1999-06-01

    We report measurements of the D{sup 0} , D{sup +} , and D{sup +}{sub s} meson lifetimes using 3.7 fb{sup {minus}1} of e{sup +}e{sup {minus}} annihilation data collected near the {Upsilon}(4S) resonance with the CLEO detector. The measured lifetimes of the D{sup 0} , D{sup +} , and D{sup +}{sub s} mesons are 408.5{plus_minus}4.1{sup +3.5}{sub {minus}3.4} fs , 1033.6{plus_minus}22.1{sup +9.9}{sub {minus}12.7} fs , and 486.3{plus_minus}15.0{sup +4.9}{sub {minus}5.1} fs . The precisions of these lifetimes are comparable to those of the best previous measurements, and the systematic errors are very different. In a single experiment we find that the ratio of the D{sup +}{sub s} and D{sup 0} lifetimes is 1.19{plus_minus}0.04 . {copyright} {ital 1999} {ital The American Physical Society}

  14. Beam-Material Interaction

    Energy Technology Data Exchange (ETDEWEB)

    Mokhov, N. V. [Fermilab; Cerutti, F. [CERN

    2016-01-01

    Th is paper is motivated by the growing importance of better understanding of the phenomena and consequences of high-intensity energetic particle beam interactions with accelerator, generic target, and detector components. It reviews the principal physical processes of fast-particle interactions with matter, effects in materials under irradiation, materials response, related to component lifetime and performance, simulation techniques, and methods of mitigating the impact of radiation on the components and environment in challenging current and future applications.

  15. Beam-Material Interaction

    CERN Document Server

    Mokhov, N.V.

    2016-01-01

    Th is paper is motivated by the growing importance of better understanding of the phenomena and consequences of high- intensity energetic particle beam interactions with accelerator, generic target , and detector components. It reviews the principal physical processes of fast-particle interactions with matter, effects in materials under irradiation, materials response, related to component lifetime and performance, simulation techniques, and methods of mitigating the impact of radiation on the components and envir onment in challenging current and future application

  16. Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant to Part-per-Million Precision

    NARCIS (Netherlands)

    Webber, D. M.; Tishchenko, V.; Peng, Q.; Battu, S.; Carey, R. M.; Chitwood, D. B.; Crnkovic, J.; Debevec, P. T.; Dhamija, S.; Earle, W.; Gafarov, A.; Giovanetti, K.; Gorringe, T. P.; Gray, F. E.; Hartwig, Z.; Hertzog, D. W.; Johnson, B.; Kammel, P.; Kiburg, B.; Kizilgul, S.; Kunkle, J.; Lauss, B.; Logashenko, I.; Lynch, K. R.; McNabb, R.; Miller, J. P.; Mulhauser, F.; Onderwater, C. J. G.; Phillips, J.; Rath, S.; Roberts, B. L.; Winter, P.; Wolfe, B.

    2011-01-01

    We report a measurement of the positive muon lifetime to a precision of 1.0 ppm; it is the most precise particle lifetime ever measured. The experiment used a time-structured, low-energy muon beam and a segmented plastic scintillator array to record more than 2 X 10(12) decays. Two different stoppin

  17. A Hybrid Lifetime Extended Directional Approach for WBANs.

    Science.gov (United States)

    Li, Changle; Yuan, Xiaoming; Yang, Li; Song, Yueyang

    2015-11-05

    Wireless Body Area Networks (WBANs) can provide real-time and reliable health monitoring, attributing to the human-centered and sensor interoperability properties. WBANs have become a key component of the ubiquitous eHealth (electronic health) revolution that prospers on the basis of information and communication technologies. The prime consideration in WBAN is how to maximize the network lifetime with battery-powered sensor nodes in energy constraint. Novel solutions in Medium Access Control (MAC) protocols are imperative to satisfy the particular BAN scenario and the need of excellent energy efficiency in healthcare applications. In this paper, we propose a hybrid Lifetime Extended Directional Approach (LEDA) MAC protocol based on IEEE 802.15.6 to reduce energy consumption and prolong network lifetime. The LEDA MAC protocol takes full advantages of directional superiority in energy saving that employs multi-beam directional mode in Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) and single-beam directional mode in Time Division Multiple Access (TDMA) for alternative in data reservation and transmission according to the traffic varieties. Moreover, the impacts of some inherent problems of directional antennas such as deafness and hidden terminal problem can be decreased owing to that all nodes generate individual beam according to user priorities designated. Furthermore, LEDA MAC employs a Dynamic Polled Allocation Period (DPAP) for burst data transmissions to increase the network reliability and adaptability. Extensive analysis and simulation results show that the proposed LEDA MAC protocol achieves extended network lifetime with improved performance compared with IEEE 802.15.6.

  18. Precision Excited State Lifetime Measurements for Atomic Parity Violation and Atomic Clocks

    Science.gov (United States)

    Sell, Jerry; Patterson, Brian; Gearba, Alina; Snell, Jeremy; Knize, Randy

    2016-05-01

    Measurements of excited state atomic lifetimes provide a valuable test of atomic theory, allowing comparisons between experimental and theoretical transition dipole matrix elements. Such tests are important in Rb and Cs, where atomic parity violating experiments have been performed or proposed, and where atomic structure calculations are required to properly interpret the parity violating effect. In optical lattice clocks, precision lifetime measurements can aid in reducing the uncertainty of frequency shifts due to the surrounding blackbody radiation field. We will present our technique for precisely measuring excited state lifetimes which employs mode-locked ultrafast lasers interacting with two counter-propagating atomic beams. This method allows the timing in the experiment to be based on the inherent timing stability of mode-locked lasers, while counter-propagating atomic beams provides cancellation of systematic errors due to atomic motion to first order. Our current progress measuring Rb excited state lifetimes will be presented along with future planned measurements in Yb.

  19. Development of a high average current polarized electron source with long cathode operational lifetime

    Energy Technology Data Exchange (ETDEWEB)

    C. K. Sinclair; P. A. Adderley; B. M. Dunham; J. C. Hansknecht; P. Hartmann; M. Poelker; J. S. Price; P. M. Rutt; W. J. Schneider; M. Steigerwald

    2007-02-01

    Substantially more than half of the electromagnetic nuclear physics experiments conducted at the Continuous Electron Beam Accelerator Facility of the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory) require highly polarized electron beams, often at high average current. Spin-polarized electrons are produced by photoemission from various GaAs-based semiconductor photocathodes, using circularly polarized laser light with photon energy slightly larger than the semiconductor band gap. The photocathodes are prepared by activation of the clean semiconductor surface to negative electron affinity using cesium and oxidation. Historically, in many laboratories worldwide, these photocathodes have had short operational lifetimes at high average current, and have often deteriorated fairly quickly in ultrahigh vacuum even without electron beam delivery. At Jefferson Lab, we have developed a polarized electron source in which the photocathodes degrade exceptionally slowly without electron emission, and in which ion back bombardment is the predominant mechanism limiting the operational lifetime of the cathodes during electron emission. We have reproducibly obtained cathode 1/e dark lifetimes over two years, and 1/e charge density and charge lifetimes during electron beam delivery of over 2?105???C/cm2 and 200 C, respectively. This source is able to support uninterrupted high average current polarized beam delivery to three experimental halls simultaneously for many months at a time. Many of the techniques we report here are directly applicable to the development of GaAs photoemission electron guns to deliver high average current, high brightness unpolarized beams.

  20. Developing an 'atomic clock' for fission lifetime measurements

    Energy Technology Data Exchange (ETDEWEB)

    Wilschut, H.W.; Kravchuk, V.L

    2004-04-05

    The relevance of measuring fission lifetimes of hot nuclei is briefly discussed. It is shown that K X-ray emission prior to fission can be used to measure fission lifetimes. The preparation of the K-shell hole, the simultaneous nuclear excitation, and the analysis of the X-ray spectra is described. First results of a measurement using a {sup 20}Ne beam of 30 MeV/nucleon on a {sup 232}Th target are reported.

  1. Angular distributions as lifetime probes

    Energy Technology Data Exchange (ETDEWEB)

    Dror, Jeff Asaf; Grossman, Yuval [Department of Physics, LEPP, Cornell University,Ithaca, NY 14853 (United States)

    2014-06-27

    If new TeV scale particles are discovered, it will be important to determine their width. There is, however, a problematic region, where the width is too small to be determined directly, and too large to generate a secondary vertex. For a collection of colored, spin polarized particles, hadronization depolarizes the particles prior to their decay. The amount of depolarization can be used to probe the lifetime in the problematic region. In this paper we apply this method to a realistic scenario of a top-like particle that can be produced at the LHC. We study how depolarization affects the angular distributions of the decay products and derive an equation for the distributions that is sensitive to the lifetime.

  2. Angular Distributions as Lifetime Probes

    CERN Document Server

    Dror, Jeff Asaf

    2013-01-01

    If new TeV scale particles are discovered, it will be important to determine their width. There is, however, a problematic region, where the width is too small to be determined directly, and too large to generate a secondary vertex. For a collection of colored, spin polarized particles, hadronization depolarizes the particles prior to their decay. The amount of depolarization can be used to probe the lifetime in the problematic region. In this paper we apply this method to a realistic scenario of a top-like particle that can be produced at the LHC. We study how depolarization affects the angular distributions of the decay products and derive an equation for the distributions that is sensitive to the lifetime.

  3. Positron annihilation lifetime study of radiation-damaged natural zircons

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, J. [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra (Australia); Gaugliardo, P. [Centre for Antimatter-Matter Studies, School of Physics, University of Western Australia (Australia); Farnan, I.; Zhang, M. [Department of Earth Sciences, University of Cambridge (United Kingdom); Vance, E.R.; Davis, J.; Karatchevtseva, I.; Knott, R.B. [Australian Nuclear Science and Technology Organisation (Australia); Mudie, S. [The Australian Synchrotron, Victoria (Australia); Buckman, S.J. [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra (Australia); Institute for Mathematical Sciences, University of Malaya, Kuala Lumpur (Malaysia); Sullivan, J.P., E-mail: james.sullivan@anu.edu.au [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra (Australia)

    2016-04-01

    Zircons are a well-known candidate waste form for actinides and their radiation damage behaviour has been widely studied by a range of techniques. In this study, well-characterised natural single crystal zircons have been studied using Positron Annihilation Lifetime Spectroscopy (PALS). In some, but not all, of the crystals that had incurred at least half of the alpha-event damage of ∼10{sup 19} α/g required to render them structurally amorphous, PALS spectra displayed long lifetimes corresponding to voids of ∼0.5 nm in diameter. The long lifetimes corresponded to expectations from published Small-Angle X-ray Scattering data on similar samples. However, the non-observation by PALS of such voids in some of the heavily damaged samples may reflect large size variations among the voids such that no singular size can be distinguished or. Characterisation of a range of samples was also performed using scanning electron microscopy, optical absorption spectroscopy, Raman scattering and X-ray scattering/diffraction, with the degree of alpha damage being inferred mainly from the Raman technique and X-ray diffraction. The observed void diameters and intensities of the long lifetime components were changed somewhat by annealing at 700 °C; annealing at 1200 °C removed the voids entirely. The voids themselves may derive from He gas bubbles or voids created by the inclusion of small quantities of organic and hydrous matter, notwithstanding the observation that no voidage was evidenced by PALS in two samples containing hydrous and organic matter. - Highlights: • Study of a range of naturally occurring zircons damaged by alpha radiation. • Characterised using a range of techniques, including PALS spectroscopy. • Effects on hydrous material appear important, rather than direct radiation damage. • Annealing is shown to remove the observed voids.

  4. Lifetime of MCP-PMTs

    Science.gov (United States)

    Lehmann, A.; Britting, A.; Eyrich, W.; Pfaffinger, M.; Uhlig, F.; Belias, A.; Dzhygadlo, R.; Gerhardt, A.; Götzen, K.; Kalicy, G.; Krebs, M.; Lehmann, D.; Nerling, F.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Zühlsdorf, M.; Düren, M.; Etzelmüller, E.; Föhl, K.; Hayrapetyan, A.; Kröck, B.; Merle, O.; Rieke, J.; Schmidt, M.; Cowie, E.; Keri, T.; Achenbach, P.; Cardinali, M.; Hoek, M.; Lauth, W.; Schlimme, S.; Sfienti, C.; Thiel, M.

    2016-05-01

    The hadron identification in the PANDA experiment at FAIR will be done with DIRC detectors. Because of design and space reasons the sensors of the DIRCs have to be placed inside the strong magnetic field of the solenoid. As the favored photon sensors microchannel-plate photomultipliers (MCP-PMTs) were identified. However, these devices showed serious aging problems until very recently, which manifest themselves by a fast degrading quantum efficiency (QE) of the photo cathode (PC). This is mainly due to feedback ions from the residual gas. In this paper we discuss the recently accomplished huge improvements in the lifetime of MCP-PMTs. With innovative countermeasures applied to the MCP-PMTs in the attempt to reduce the aging effects the manufacturers were able to increase the lifetime of MCP-PMT prototypes by almost two orders of magnitude compared to the former commercially available devices. Our group has studied the aging of MCP-PMTs for more than four years by simultaneously illuminating different types of lifetime-enhanced MCP-PMTs at the same photon rate. Gain, dark count rate, and QE as a function of the wavelength and the PC surface were measured in regular time intervals and studied in dependence of the integrated anode charge. We observe that MCP-PMTs treated with an atomic layer deposition (ALD) technique are by far the best devices available now. A lifetime of up to 10 C/cm2 integrated anode charge was reached with these sensors. This is sufficient for both PANDA DIRCs.

  5. Precise atomic radiative lifetime via photoassociative spectroscopy of ultracold lithium

    NARCIS (Netherlands)

    McAlexander, W.I.; Abraham, E.R.I.; Ritchie, N.W.M.; Williams, C.J.; Stoof, H.T.C.; Hulet, R.G.

    1995-01-01

    We have obtained spectra of the high-lying vibrational levels of the 13Σg+ state of 6Li2 via photoassociation of ultracold 6Li atoms confined in a magneto-optical trap. The 13Σg+ state of the diatomic molecule correlates to a 2S1/2 state atom plus a 2P1/2 state atom. The long-range part of the molec

  6. Capillary condensation in porous alumina observed by positronium lifetime spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Eugeniu [National Institute for Nuclear Physics and Engineering-Horia Hulubei, Atomistilor Street 407, CP MG 06, Magurele, Bucharest (Romania); Center for Advanced Studies in Physics of the Roumanian Academy, Casa Academiei Romane, Calea 13 Septembrie No. 13, Bucharest (Romania); Vata, Ion [National Institute for Nuclear Physics and Engineering-Horia Hulubei, Atomistilor Street 407, CP MG 06, Magurele, Bucharest (Romania)], E-mail: vata@ifin.nipne.ro; Toderian, Stefan; Dudu, Dorin; Rusen, Ion; Stefan, Nitisor [National Institute for Nuclear Physics and Engineering-Horia Hulubei, Atomistilor Street 407, CP MG 06, Magurele, Bucharest (Romania)

    2008-10-31

    The PALS method based on time distribution measurements has been used to study capillary condensation of different gases adsorbed in microporous alumina powder. The isotherms exhibit features which are associated with a shifted gas-liquid transition. The sorption and desorption processes are irreversible presenting a hysteresis effect. Suggestions on some new aspects of the capillary condensation dynamics are made.

  7. Rapid evaluation of ion thruster lifetime using optical emission spectroscopy

    Science.gov (United States)

    Rock, B. A.; Parsons, M. L.; Mantenieks, M. A.

    1985-01-01

    A major life-limiting phenomenon of electric thrusters is the sputter erosion of discharge chamber components. Thrusters for space propulsion are required to operate for extended periods of time, usually in excess of 10,000 hr. Lengthy and very costly life-tests in high-vacuum facilities have been required in the past to determine the erosion rates of thruster components. Alternative methods for determining erosion rates which can be performed in relatively short periods of time at considerably lower costs are studied. An attempt to relate optical emission intensity from an ion bombarded surface (screen grid) to the sputtering rate of that surface is made. The model used a kinetic steady-state (KSS) approach, balancing the rates of population and depopulation of ten low-lying excited states of the sputtered molybdenum atom (MoI) with those of the ground state to relate the spectral intensities of the various transitions of the MoI to the population densities. Once this is accomplished, the population density can be related to the sputting rate of the target. Radiative and collisional modes of excitation and decay are considered. Since actual data has not been published for MoI excitation rate and decay constants, semiempirical equations are used. The calculated sputtering rate and intensity is compared to the measured intensity and sputtering rates of the 8 and 30 cm ion thrusters.

  8. Lifetime positron annihilation spectroscopy and photo-inactivated bacteria

    CERN Document Server

    El'nikova, L V

    2009-01-01

    Combined positron and infrared irradiations in the applications of photodynamical therapy (PDT) are studied analytically. Objectives and goals of PDT are killing or irreversible oxidative damage of pathogenic cells, or rather their cell walls, cell membranes, peptides, and nucleic acids by photo-activated oxygen of photosentizer injected into the target cell during light irradiation. On the trial system "Escherichia coli--T$_4$MPyP" the main positron interactions with media are evaluated to validate the perspectives of that use.

  9. Cw and time-resolved spectroscopy in homoepitaxial GaN films and GaN-GaAlN quantum wells grown by molecular beam epitaxy.

    OpenAIRE

    Taliercio, Thierry; Gallart, Mathieu; Lefebvre, Pierre; Morel, Aurélien; Gil, Bernard; Allègre, Jacques; Grandjean, Nicolas; Massies, Jean; Grzegory, Izabella; Porowsky, Sylvester

    2001-01-01

    International audience; We have grown GaN films and GaN–AlGaN quantum wells (QWs) on homoepitaxial substrates, by molecular beam epitaxy using ammonia. Both the GaN film and the QW are found to have superior excitonic recombination properties which are extremely promising for the development of indium free ultra-violet lasers based on nitrides.

  10. Singlet Exciton Lifetimes in Conjugated Polymer Films for Organic Solar Cells

    KAUST Repository

    Dimitrov, Stoichko

    2016-01-13

    The lifetime of singlet excitons in conjugated polymer films is a key factor taken into account during organic solar cell device optimization. It determines the singlet exciton diffusion lengths in polymer films and has a direct impact on the photocurrent generation by organic solar cell devices. However, very little is known about the material properties controlling the lifetimes of singlet excitons, with most of our knowledge originating from studies of small organic molecules. Herein, we provide a brief summary of the nature of the excited states in conjugated polymer films and then present an analysis of the singlet exciton lifetimes of 16 semiconducting polymers. The exciton lifetimes of seven of the studied polymers were measured using ultrafast transient absorption spectroscopy and compared to the lifetimes of seven of the most common photoactive polymers found in the literature. A plot of the logarithm of the rate of exciton decay vs. the polymer optical bandgap reveals a medium correlation between lifetime and bandgap, thus suggesting that the Energy Gap Law may be valid for these systems. This therefore suggests that small bandgap polymers can suffer from short exciton lifetimes, which may limit their performance in organic solar cell devices. In addition, the impact of film crystallinity on the exciton lifetime was assessed for a small bandgap diketopyrrolopyrrole co-polymer. It is observed that the increase of polymer film crystallinity leads to reduction in exciton lifetime and optical bandgap again in agreement with the Energy Gap Law.

  11. Singlet Exciton Lifetimes in Conjugated Polymer Films for Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    Stoichko D. Dimitrov

    2016-01-01

    Full Text Available The lifetime of singlet excitons in conjugated polymer films is a key factor taken into account during organic solar cell device optimization. It determines the singlet exciton diffusion lengths in polymer films and has a direct impact on the photocurrent generation by organic solar cell devices. However, very little is known about the material properties controlling the lifetimes of singlet excitons, with most of our knowledge originating from studies of small organic molecules. Herein, we provide a brief summary of the nature of the excited states in conjugated polymer films and then present an analysis of the singlet exciton lifetimes of 16 semiconducting polymers. The exciton lifetimes of seven of the studied polymers were measured using ultrafast transient absorption spectroscopy and compared to the lifetimes of seven of the most common photoactive polymers found in the literature. A plot of the logarithm of the rate of exciton decay vs. the polymer optical bandgap reveals a medium correlation between lifetime and bandgap, thus suggesting that the Energy Gap Law may be valid for these systems. This therefore suggests that small bandgap polymers can suffer from short exciton lifetimes, which may limit their performance in organic solar cell devices. In addition, the impact of film crystallinity on the exciton lifetime was assessed for a small bandgap diketopyrrolopyrrole co-polymer. It is observed that the increase of polymer film crystallinity leads to reduction in exciton lifetime and optical bandgap again in agreement with the Energy Gap Law.

  12. Minority carrier lifetime in indium phosphide

    Science.gov (United States)

    Jenkins, Phillip; Landis, Geoffrey A.; Weinberg, Irving; Kneisel, Keith

    1991-01-01

    Transient photoluminescence is used to measure the minority carrier lifetime on n-type and p-type InP wafers. The measurements show that unprocessed InP wafers have very high minority carrier lifetimes. Lifetimes of 200 ns and 700 ns were observed for lightly-doped p- and n-type material respectively. Lifetimes over 5 ns were found in heavily doped n-type material.

  13. Inelastic quasiparticle lifetimes of the Shockley surface state band on Ni(111)

    Energy Technology Data Exchange (ETDEWEB)

    Braun, Kai-Felix [Ohio University, Nanoscale and Quantum Phenomena Institute, Physics and Astronomy Department, Athens, OH (United States); Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Hla, Saw-Wai [Ohio University, Nanoscale and Quantum Phenomena Institute, Physics and Astronomy Department, Athens, OH (United States); Samango GmbH, Darmstadt (Germany)

    2010-03-15

    We present a study of the low-energy quasiparticle lifetimes of the Shockley surface state on the Ni(111) surface with scanning tunnelling spectroscopy. By measuring the coherence length of the decaying standing wave pattern at straight step edges electron and hole lifetimes have been determined. The values of the lifetime measured on this ferromagnetic surface show to be considerable smaller than the values obtained from noble metal surfaces. This is explained by differences in the electron density of states at the Fermi energy but has to include substantial spin-flip scattering. Furthermore hole lifetimes appear to be larger than electron lifetimes with the same excitation energy. Although only results for the majority spin component are presented, a spin-dependent selfenergy is expected. (orig.)

  14. Inequivalence of single-particle and population lifetimes in a cuprate superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shuolong [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Sobota, J. A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Leuenberger, D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); He, Y. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Hashimoto, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Lu, D. H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Eisaki, H. [National Institute of Advanced Industrial Science and Technology, Ibaraki (Japan); Kirchmann, P. S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Shen, Z. -X. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States)

    2015-06-15

    We study optimally doped Bi-2212 (Tc=96 K) using femtosecond time- and angle-resolved photoelectron spectroscopy. Energy-resolved population lifetimes are extracted and compared with single-particle lifetimes measured by equilibrium photoemission. The population lifetimes deviate from the single-particle lifetimes in the low excitation limit by 1–2 orders of magnitude. Fundamental considerations of electron scattering unveil that these two lifetimes are in general distinct, yet for systems with only electron-phonon scattering they should converge in the low-temperature, low-fluence limit. As a result, the qualitative disparity in our data, even in this limit, suggests that scattering channels beyond electron-phonon interactions play a significant role in the electron dynamics of cuprate superconductors.

  15. Optical Faraday Cup for Heavy Ion Beams

    Energy Technology Data Exchange (ETDEWEB)

    Bieniosek, Frank; Bieniosek, F.M.; Eylon, S.; Roy, P.K.; Yu, S.S.

    2007-06-25

    We have been using alumina scintillators for imaging beams in heavy-ion beam fusion experiments in 2 to 4 transverse dimensions [1]. The scintillator has a limited lifetime under bombardment by the heavy ion beams. As a possible replacement for the scintillator, we are studying the technique of imaging the beam on a gas cloud. A gas cloud for imaging the beam may be created on a solid hole plate placed in the path of the beam, or by a localized gas jet. It is possible to image the beam using certain fast-quenching optical lines that closely follow beam current density and are independent of gas density. We describe this technique and show preliminary experimental data. This approach has promise to be a new fast beam current diagnostic on a nanosecond time scale.

  16. Mesopore quality determines the lifetime of hierarchically structured zeolite catalysts

    Science.gov (United States)

    Milina, Maria; Mitchell, Sharon; Crivelli, Paolo; Cooke, David; Pérez-Ramírez, Javier

    2014-05-01

    Deactivation due to coking limits the lifetime of zeolite catalysts in the production of chemicals and fuels. Superior performance can be achieved through hierarchically structuring the zeolite porosity, yet no relation has been established between the mesopore architecture and the catalyst lifetime. Here we introduce a top-down demetallation strategy to locate mesopores in different regions of MFI-type crystals with identical bulk porous and acidic properties. In contrast, well-established bottom-up strategies as carbon templating and seed silanization fail to yield materials with matching characteristics. Advanced characterization tools capable of accurately discriminating the mesopore size, distribution and connectivity are applied to corroborate the concept of mesopore quality. Positron annihilation lifetime spectroscopy proves powerful to quantify the global connectivity of the intracrystalline pore network, which, as demonstrated in the conversions of methanol or of propanal to hydrocarbons, is closely linked to the lifetime of zeolite catalysts. The findings emphasize the need to aptly tailor hierarchical materials for maximal catalytic advantage.

  17. Neutron lifetime measurement on setups with gravitational trap

    Energy Technology Data Exchange (ETDEWEB)

    Serebrov, A. P., E-mail: serebrov@pnpi.spb.ru; Fomin, A. K.; Kharitonov, A. G.; Varlamov, V. E.; Kolomenskiy, E. A.; Krasnoshchekova, I. A.; Chechkin, A. V. [National Research Centre “Kurchatov Institute”, Petersburg Nuclear Physics Institute (Russian Federation)

    2016-01-15

    Currently, the best accuracy of neutron lifetime measurements has been attained in the experiment with a gravitational trap for ultracold neutrons (UCNs), performed at the Petersburg Nuclear Physics Institute (PNPI); the measured lifetime was 878.5 ± 0.8 s. A new setup with a big gravitational trap has been designed to continue the methods and approaches used in the previous experiment. It is planned to reduce the measurement error to 0.2 s, i.e., improve the existing accuracy by a factor of 4. The spectrometer was designed at PNPI and installed on the PF2/MAM beam at the Institute Laue–Langevin. Test experiments have been performed.

  18. Growth temperature dependence of exciton lifetime in wurtzite InP nanowires grown on silicon substrates

    Science.gov (United States)

    Chauvin, N.; Hadj Alouane, M. H.; Anufriev, R.; Khmissi, H.; Naji, K.; Patriarche, G.; Bru-Chevallier, C.; Gendry, M.

    2012-01-01

    InP nanowires grown on silicon substrate are investigated using time-resolved spectroscopy. A strong modification of the exciton lifetime is observed (from 0.11 to 1.2 ns) when the growth temperature is increased from 340 °C to 460 °C. This strong dependence is not related to the density of zinc-blende insertions in the wurtzite nanowires or to the wurtzite exciton linewidth. The excitation power dependence of the lifetime and linewidth is investigated, and these results allow us to interpret the growth temperature dependence on the lifetime as a consequence of the reduction of the surface recombination velocity with the growth temperature.

  19. Note: Rapid measurement of fluorescence lifetimes using SiPM detection and waveform sampling

    Science.gov (United States)

    Tsai, H.-M.; Souris, J. S.; Kim, H.-J.; Cheng, S.-H.; Chen, L.; Lo, L.-W.; Chen, C.-T.; Kao, C.-M.

    2017-09-01

    In fluorescence spectroscopy and imaging, fluorescence lifetime measurement—assessing the average time fluorophores spend in their excited state before returning to their ground state—offers a number of advantages over quantifying fluorescence intensities that include resistance to photo-bleaching and independence from fluorophore concentration, excitation intensity, and measurement methodology. Despite growing interest, fluorescence lifetime techniques frequently mandate relatively complex instrumentation, slow data acquisition rates, and significant data analyses. In this work, we demonstrate the feasibility of measuring fluorescence lifetimes using off-the-shelf analog silicon photomultipliers and switched-capacitor array waveform sampling techniques, with precision matching that of much larger and more elaborate commercial instruments.

  20. Long-Lifetime Low-Scatter Neutron Polarization Target

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Jonathan M. Richardson

    2004-07-09

    Polarized neutrons scattering is an important technology for characterizing magnetic and other materials. Polarized helium three (P-3He) is a novel technology for creating polarized beams and, perhaps more importantly, for the analysis of polarization in highly divergent scattered beams. Analysis of scattered beams requires specialized targets with complex geometries to ensure accurate results. Special materials and handling procedures are required to give the targets a long useful lifetime. In most cases, the targets must be shielded from stray magnetic fields from nearby equipment. SRL has developed and demonstrated hybrid targets made from glass and aluminum. We have also developed and calibrated a low-field NMR system for measuring polarization lifetimes. We have demonstrated that our low-field system is able to measure NMR signals in the presence of conducting (metallic) cell elements. We have also demonstrated a non-magnetic valve that can be used to seal the cells. We feel that these accomplishments in Phase I are sufficient to ensure a successful Phase II program. The commercial market for this technology is solid. There are over nine neutron scattering centers in the US and Canada and over 22 abroad. Currently, the US plans to build a new $1.4B scattering facility called the Spallation Neutron Source (SNS). The technology developed in this project will allow SRL to supply targets to both existing and future facilities. SRL is also involved with the application of P-3He to medical imaging.

  1. {gamma}-spectroscopy and radioactive beams: search for highly deformed exotic nuclei; Detection {gamma} et faisceaux radioactifs: recherche de noyaux exotiques tres deformes

    Energy Technology Data Exchange (ETDEWEB)

    Rosse, B

    2006-07-15

    This work is devoted to the search for highly deformed nuclei under extreme conditions of isospin, located near the proton drip-line, around A {approx} 130. The experiment was performed at GANIL (Caen) with the SPIRAL radioactive beam facility. The nuclei of interest were produced by fusion-evaporation reactions induced by the neutron deficient Kr{sup 76} radioactive beam (T1/2 = 14.8 h). {gamma}-rays were detected by the EXOGAM array, composed of 11 segmented germanium clover detectors, for which a new segment calibration method has been developed. To extract fusion-evaporation events of a overwhelming background due to the radioactivity of the beam, the EXOGAM array was coupled with the light charged particle detector DIAMANT and the high acceptance VAMOS spectrometer. The latter was used for the first time to detect fusion-evaporation residues. The detailed data analysis allowed us to demonstrate that the EXOGAM + DIAMANT + VAMOS coupling is operational and essential to investigate the structure of these nuclei. Furthermore, the first {gamma} transition was observed in the very exotic odd-odd Pm{sup 130} nucleus. The results have been interpreted with static and dynamic self-consistent microscopic calculations in collaboration with the Theoretical Physicists of the IPN Lyon. (author)

  2. Studies of Landé gJ-factors of singly ionized neodymium isotopes (142, 143 and 145) at relatively small magnetic fields up to 334 G by collinear laser ion beam spectroscopy

    Science.gov (United States)

    Werbowy, Slawomir; Windholz, Laurentius

    2017-01-01

    The Zeeman splitting at moderate magnetic fields (up to 334 G) of 20 lines of Nd II, covering the part 569.89 nm to 617.05 nm of the visible spectral range were investigated. We used a Doppler-free collinear laser ion beam spectroscopy technique supported by a precise computer analysis. From the Zeeman effect studies we re-investigated the Landé g J factors for 20 odd levels between 22 850 and 30 002 cm-1 and 11 even levels lying between 6005 and 12 460 cm-1. We compared our data with other available experimental and theoretical values. We achieved an accuracy better than that of other authors, making our data valuable for future theoretical parametric studies.

  3. Personality, IQ, and Lifetime Earnings

    DEFF Research Database (Denmark)

    Gensowski, Miriam

    2014-01-01

    Talented individuals are seen as drivers of long-term growth, but how do they realize their full potential? In this paper, I show that lifetime earnings of high-IQ men and women are substantially influenced by their personality traits, in addition to intelligence and education. Personality traits......, as identified in a factor model, significantly affect earnings, but not for young workers. The effects are furthermore heterogeneous by educational attainment. For women, personality traits do not affect family earnings in the same way as own earnings. Personality and IQ also influence earnings indirectly...

  4. Estimation of luminescence lifetime in frequency domain

    Institute of Scientific and Technical Information of China (English)

    Zhang Fu-Jun; Xu Zheng; Zhao Su-Ling; Lou Zhi-Dong; Yang Sheng-Yi; Xu Xu-Rong

    2006-01-01

    Absorption is the origin of luminescence. But it must be noticed that the lifetime of luminescence might reversely influence the rate of absorption. In this paper, it is reported that the luminescence intensity of copper and manganese changes with the driving frequency at constant voltage. The variation of luminescent intensity depends only on the lifetime of luminescence but not on the type of quenching or other factors. Generally the rate of absorption is dominantly determined by the material property and the lifetime of luminescence centres, the absorption of shorter lifetime centre will be larger than that of the longer lifetime centre at the same excited condition.

  5. Positronium lifetime in porous VP-DVB copolymer

    Energy Technology Data Exchange (ETDEWEB)

    Zaleski, Radoslaw [Institute of Physics, Maria Curie-Sklodowska University, Lublin (Poland); Goworek, Jacek; Maciejewska, Malgorzata [Faculty of Chemistry, Maria Curie-Sklodowska University, Lublin (Poland)

    2009-11-15

    Porous 1-vinyl-2-pyrrolidone-divinylbenzene copolymer was studied using Positron Annihilation Lifetime Spectroscopy. A set of spectra measured at various temperatures was analysed using two methods: model parameters fitting and quantified maximum entropy. Similarity of the results obtained by entirely different methods ensure that distortion of the results arisen from inappropriate data processing was minimized. Temperature dependence of the experimental ortho-positronium lifetimes was compared to predictions of the Extended Tao-Eldrup model. Very good agreement in whole temperature range was found for empirical parameter {delta}=0.15 nm. Basing on PALS data and the Extended Tao-Eldrup model the distribution of free volume sizes was derived. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Carrier lifetimes in thin-film photovoltaics

    Science.gov (United States)

    Baek, Dohyun

    2015-09-01

    The carrier lifetimes in thin-film solar cells are reviewed and discussed. Shockley-Read-Hall recombination is dominant at low carrier density, Auger recombination is dominant under a high injection condition and high carrier density, and surface recombination is dominant under any conditions. Because the surface photovoltage technique is insensitive to the surface condition, it is useful for bulk lifetime measurements. The photoconductance decay technique measures the effective recombination lifetime. The time-resolved photoluminescence technique is very useful for measuring thin-film semiconductor or solar-cell materials lifetime, because the sample is thin, other techniques are not suitable for measuring the lifetime. Many papers have provided time-resolved photoluminescence (TRPL) lifetimes for copper-indium-gallium-selenide (CIGS) and CdTe thin-film solar cell. The TRPL lifetime strongly depends on open-circuit voltage and conversion efficiency; however, the TRPL life time is insensitive to the short-circuit current.

  7. Lifetime Measurement of 26O

    Science.gov (United States)

    Redpath, Thomas; MoNA Collaboration

    2017-01-01

    An interesting property of some neutron-unbound systems is true two-neutron emission where the neutrons are emitted simultaneously as opposed to a sequential decay through an intermediate state. Since neutrons are only affected by the angular momentum barrier, the timescale for this process is much shorter than for two proton emission which is dominated by the Coulomb barrier. One such case is 26O where a very low decay energy was measured and the two valence neutrons are expected to occupy d-wave orbitals. Also, the ground state of 25O is located 700 keV higher. In a first experiment, the MoNA collaboration extracted a lifetime of 4 .5-1 . 5 + 1 . 1 (stat) +/- 3(syst) ps with a confidence level of 82%. Recently, an experiment dedicated to measuring the 26O lifetime in order to improve the confidence level of the measurement was performed at NSCL. The experiment utilized a newly developed segmented target which increased the statistics without degrading the resolution. Preliminary results will be presented. NSF PHY-1002511, DOE-NNSA DE-NA0000979.

  8. Carrier Bulk-Lifetime Measurements

    Directory of Open Access Journals (Sweden)

    M. Solcansky

    2012-01-01

    Full Text Available For the measurement of the minority carrier bulk-lifetime the characterization method MW-PCD is used, where the result of measurement is the effective carrier lifetime, which is very dependent on the surface recombination velocity and therefore on the quality of a silicon surface passivation. This work deals with an examination of a different solution types for the chemical passivation of a silicon surface. Various solutions are tested on silicon wafers for their consequent comparison. The main purpose is to find optimal solution, which suits the requirements of a time stability and start-up velocity of passivation, reproducibility of the measurements and a possibility of a perfect cleaning of a passivating solution remains from a silicon surface, so that the parameters of a measured silicon wafer will not worsen and there will not be any contamination of the other wafers series in the production after a repetitive return of the measured wafer into the production process. The cleaning process itself is also a subject of a development.

  9. Dynamic fluorescence lifetime imaging based on acousto-optic deflectors

    Science.gov (United States)

    Yan, Wei; Peng, Xiao; Qi, Jing; Gao, Jian; Fan, Shunping; Wang, Qi; Qu, Junle; Niu, Hanben

    2014-11-01

    We report a dynamic fluorescence lifetime imaging (D-FLIM) system that is based on a pair of acousto-optic deflectors for the random regions of interest (ROI) study in the sample. The two-dimensional acousto-optic deflector devices are used to rapidly scan the femtosecond excitation laser beam across the sample, providing specific random access to the ROI. Our experimental results using standard fluorescent dyes in live cancer cells demonstrate that the D-FLIM system can dynamically monitor the changing process of the microenvironment in the ROI in live biological samples.

  10. Silicon avalanche photodiode operation and lifetime analysis for small satellites.

    Science.gov (United States)

    Tan, Yue Chuan; Chandrasekara, Rakhitha; Cheng, Cliff; Ling, Alexander

    2013-07-15

    Silicon avalanche photodiodes (APDs) are sensitive to operating temperature fluctuations and are also susceptible to radiation flux expected in satellite-based quantum experiments. We introduce a low power voltage adjusting mechanism to overcome the effects of in-orbit temperature fluctuations. We also present data on the performance of Si APDs after irradiation (γ-ray and proton beam). Combined with an analysis of expected orbital irradiation, we propose that a Si APD in a 400 km equatorial orbit may operate beyond the lifetime of the satellite.

  11. Silicon avalanche photodiode operation and lifetime analysis for small satellites

    CERN Document Server

    Tan, Yue Chuan; Cheng, Cliff; Ling, Alexander

    2013-01-01

    Silicon avalanche photodiodes (APDs) are sensitive to operating temperature fluctuations and are also susceptible to radiation flux expected in satellite-based quantum experiments. We introduce a low power voltage adjusting mechanism to overcome the effects of in-orbit temperature fluctuations. We also present data on the performance of Si APDs after irradiation (gamma-ray and proton beam). Combined with an analysis of expected orbital irradiation, we propose that a Si APD in a 400 km equatorial orbit may operate beyond the lifetime of the satellite.

  12. Argon metastable dynamics and lifetimes in a direct current microdischarge

    Science.gov (United States)

    Stefanović, Ilija; Kuschel, Thomas; Schröter, Sandra; Böke, Marc

    2014-09-01

    In this paper we study the properties of a pulsed dc microdischarge with the continuous flow of argon. Argon metastable lifetimes are measured by tunable diode laser absorption spectroscopy (TDLAS) and are compared with calculated values which yield information about excitation and de-excitation processes. By increasing the gas flow-rate about 5 times from 10 to 50 sccm, the Arm lifetime increases from 1 to 5 μs due to the reduction of metastable quenching with gas impurities. Optical emission spectroscopy reveals nitrogen and water molecules as the main gas impurities. The estimated N2 density [N2] = 0.1% is too low to explain the measured metastable lifetimes. Water impurity was found to be the main de-excitation source of argon metastable atoms due to high quenching coefficients. The water impurity level of [H2O] = 0.15% to 1% is sufficient to bring calculated metastable lifetimes in line with experiments. The maximum value of water content in the discharge compared to the argon atoms is estimated to approximately 6%, due to the large surface to volume ratio of the microdischarge. The current pulse releases the water molecules from the electrode surface and they are either re-adsorbed in the time between 0.4 ms for [H2O] = 1% and 2.6 ms for [H2O] = 0.15% or pumped out of the discharge with the speed equal to the gas flow-rate. Depending on its partial pressure, the water impurity re-adsorption time is of the order of magnitude or less then the argon gas residence time.

  13. Argon metastable dynamics and lifetimes in a direct current microdischarge

    Energy Technology Data Exchange (ETDEWEB)

    Stefanović, Ilija [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia); Kuschel, Thomas; Schröter, Sandra; Böke, Marc [Ruhr-Universität Bochum, Institute for Experimental Physics II, Universitätsstraße 150, 44780 Bochum (Germany)

    2014-09-21

    In this paper we study the properties of a pulsed dc microdischarge with the continuous flow of argon. Argon metastable lifetimes are measured by tunable diode laser absorption spectroscopy (TDLAS) and are compared with calculated values which yield information about excitation and de-excitation processes. By increasing the gas flow-rate about 5 times from 10 to 50 sccm, the Ar{sup m} lifetime increases from 1 to 5 μs due to the reduction of metastable quenching with gas impurities. Optical emission spectroscopy reveals nitrogen and water molecules as the main gas impurities. The estimated N₂ density [N₂]=0.1% is too low to explain the measured metastable lifetimes. Water impurity was found to be the main de-excitation source of argon metastable atoms due to high quenching coefficients. The water impurity level of [H₂O]=0.15% to 1% is sufficient to bring calculated metastable lifetimes in line with experiments. The maximum value of water content in the discharge compared to the argon atoms is estimated to approximately 6%, due to the large surface to volume ratio of the microdischarge. The current pulse releases the water molecules from the electrode surface and they are either re-adsorbed in the time between 0.4 ms for [H₂O]=1% and 2.6 ms for [H₂O]=0.15% or pumped out of the discharge with the speed equal to the gas flow-rate. Depending on its partial pressure, the water impurity re-adsorption time is of the order of magnitude or less then the argon gas residence time.

  14. Positron annihilation lifetime study of radiation-damaged natural zircons

    Science.gov (United States)

    Roberts, J.; Gaugliardo, P.; Farnan, I.; Zhang, M.; Vance, E. R.; Davis, J.; Karatchevtseva, I.; Knott, R. B.; Mudie, S.; Buckman, S. J.; Sullivan, J. P.

    2016-04-01

    Zircons are a well-known candidate waste form for actinides and their radiation damage behaviour has been widely studied by a range of techniques. In this study, well-characterised natural single crystal zircons have been studied using Positron Annihilation Lifetime Spectroscopy (PALS). In some, but not all, of the crystals that had incurred at least half of the alpha-event damage of ∼1019 α/g required to render them structurally amorphous, PALS spectra displayed long lifetimes corresponding to voids of ∼0.5 nm in diameter. The long lifetimes corresponded to expectations from published Small-Angle X-ray Scattering data on similar samples. However, the non-observation by PALS of such voids in some of the heavily damaged samples may reflect large size variations among the voids such that no singular size can be distinguished or. Characterisation of a range of samples was also performed using scanning electron microscopy, optical absorption spectroscopy, Raman scattering and X-ray scattering/diffraction, with the degree of alpha damage being inferred mainly from the Raman technique and X-ray diffraction. The observed void diameters and intensities of the long lifetime components were changed somewhat by annealing at 700 °C; annealing at 1200 °C removed the voids entirely. The voids themselves may derive from He gas bubbles or voids created by the inclusion of small quantities of organic and hydrous matter, notwithstanding the observation that no voidage was evidenced by PALS in two samples containing hydrous and organic matter.

  15. Proton/hydrogen-transfer coordinate of 2,5-dihydroxybenzoic acid investigated in a supersonic beam: combined IR/UV spectroscopy in the S0, S1, and D0 states.

    Science.gov (United States)

    Fricke, Holger; Bartl, Kristina; Funk, Andreas; Gerlach, Andreas; Gerhards, Markus

    2008-12-01

    As a model system for intramolecular proton/hydrogen-transfer coordinates, the structure of 2,5-dihydroxybenzoic acid is investigated for the ground, first electronically excited and also the ionic state. Combined IR/UV spectroscopy in molecular-beam experiments is applied and the experimental results are interpreted by the application of DFT and CASPT2 methods. No proton or hydrogen transfer is observed, but evidence is given for a hydrogen dislocation of the intramolecular hydrogen bond in the S(1) state and to lesser extent in the D(0) state. To obtain direct information on the proton/hydrogen-transfer coordinate, IR spectra are recorded both in the region of the OH and especially the CO stretching vibrations by also applying two new variants of combined IR/UV spectroscopy for the S(1) and D(0) states. The CO groups are directly involved in the hydrogen bond and, in contrast to the hydrogen-bonded OH groups, the CO stretching frequencies can be observed in all electronic states.

  16. Measurement of short lifetimes in highly-charged ions using a two-foil target

    Energy Technology Data Exchange (ETDEWEB)

    Berry, H.G.; Dunford, R.W.; Gemmell, D.S. [and others

    1995-08-01

    One of the frontiers in the study of the atomic physics of highly-charged ions is the measurement of lifetimes in the 100 fs to 10 ps regime. The standard technique for measuring lifetimes of states in highly-charged ions is the beam-foil time-of-flight method in which the intensity of an emission line is monitored as a function of the separation between the exciting foil and the portion of the beam being viewed by the detector. This method becomes increasingly difficult as the decay lengths of the states of interest become shorter. At a typical beam velocity of 10% of the speed of light, the beam travels 30 microns in a picosecond. The standard beam-foil time-of-flight method necessitates observation of the decay radiation within one or two decay lengths from the foil while preventing the detectors from observing the beam spot at the foil. For short-lived states this requires tight collimation of the detector with a resulting loss in solid angle. We are developing a method for measuring ultrashort atomic lifetimes utilizing a two-foil target. As a specific case to demonstrate the feasibility of our method, we are studying the decay of the 2 {sup 3}P{sub 2} level in helium-like Kr{sup 34+}. This level has a calculated lifetime of 9.5 ps which corresponds to a decay length of 380 {mu}m. For krypton, theory predicts that 90% of the 2 {sup 3}P{sub 2} states decay via M2 radiation to the ground state. A measurement of the lifetime of this state would contribute to an important current problem which concerns the understanding of atomic structure when both electron correlations and relativistic effects are simultaneously important.

  17. $\\gamma$- spectroscopy of n-rich $^{95,96}$Rb nuclei by the incomplete fusion reaction of $^{94}$Kr on $^{7}$Li: Introduction to HIE-ISOLDE studies of n-rich Sb and Tl isotopes with Sn and Hg radioactive beams.

    CERN Document Server

    Fornal, B; Bednarczyk, P; Cieplicka, N; Krolas, W; Maj, A; Leoni, S; Benzoni, G; Blasi, N; Bottoni, S; Bracco, A; Camera, F; Crespi, F; Million, B; Morales, A; Wieland, O; Rusek, K; Lunardi, S; Mengoni, D; Recchia, F; Ur, CA; Valiente-Dobon, J; de France, G; Clement, E; Elseviers, J; Flavigny, F; Huyse, M; Raabe, R; Sambi, S; Van Duppen, P; Sferrazza, M; Simpson, G; Georgiev, G; Sotty, C; Blazhev, A; German, R; Siebeck, B; Seidlitz, M; Reiter, P; Warr, N; Boenig, S; Ilieva, S; Kroell, T; Scheck, M; Thurauf, M; Gernhaeuser, R; Mucher, D; Janssens, R; Carpenter, MP; Zhu, S; Marginean, NM; Balabanski, D; Kowalska, M

    2012-01-01

    $\\gamma$- spectroscopy of n-rich $^{95,96}$Rb nuclei by the incomplete fusion reaction of $^{94}$Kr on $^{7}$Li: Introduction to HIE-ISOLDE studies of n-rich Sb and Tl isotopes with Sn and Hg radioactive beams.

  18. Solid state physics: advanced spectroscopy, scanning probe microscopy, nanostructure fabrication

    CERN Document Server

    Aghion, Stefano

    Thin films of hybrid solar cells and metal oxide semiconductors -IGZO in particular– and homogeneous PMMA polymers have been studied at the Positron Laboratory (L-NESS centre, Politecnico di Milano, Polo Territoriale di Como). A slow energy positron beam and a positron lifetime spectrometer have been employed for these studies. The positron spectroscopy information have been correlated with electrical and optical properties of the materials. The chemical composition and the morphology of voids and porosities in hybrid solar cells and thin film metal oxide semiconductors have been studied, and a strong correlation between positronium fraction, S-parameter and the electrical properties of these materials has been found. In PMMA polymers, free volume measurements have shown that the optical properties of the material depend on the presence of monomer residual fraction and even slight changes in the dimensions and concentration of free volumes. Positrons have been also applied to the study of positron to positr...

  19. Personality, IQ, and Lifetime Earnings

    DEFF Research Database (Denmark)

    Gensowski, Miriam

    2014-01-01

    , as identified in a factor model, significantly affect earnings, but not for young workers. The effects are furthermore heterogeneous by educational attainment. For women, personality traits do not affect family earnings in the same way as own earnings. Personality and IQ also influence earnings indirectly...... through education, which has sizeable positive rates of return for men in this sample. Women’s returns to education past a bachelor’s degree are lowered through worse marriage prospects, which offset gains to education in terms of own earnings. The causal effect of education is identified through matching......Talented individuals are seen as drivers of long-term growth, but how do they realize their full potential? In this paper, I show that lifetime earnings of high-IQ men and women are substantially influenced by their personality traits, in addition to intelligence and education. Personality traits...

  20. Parity lifetime of bound states in a proximitized semiconductor nanowire

    DEFF Research Database (Denmark)

    Higginbotham, Andrew Patrick; Albrecht, Sven Marian; Kirsanskas, Gediminas

    2015-01-01

    superconductors but remain relatively unexplored in semiconductor-superconductor structures, which are now being intensely pursued in the context of topological superconductivity. To this end, we introduce a new physical system comprised of a gate-confined semiconductor nanowire with an epitaxially grown...... superconductor layer, yielding an isolated, proximitized nanowire segment. We identify Andreev-like bound states in the semiconductor via bias spectroscopy, determine the characteristic temperatures and magnetic fields for quasiparticle excitations, and extract a parity lifetime (poisoning time) of the bound...... state in the semiconductor exceeding 10 ms....

  1. Lifetime Measurements for Electric-Dipole △ n = 0 Transitions in the Beryllium-Like Sulfur

    Institute of Scientific and Technical Information of China (English)

    DU Shu-Bin; YANG Zhi-Hu; CHANG Hong-Wei; SU Hong

    2005-01-01

    @@ We have measured lifetimes of △n = 0 allowed transitions in beryllium-like sulfur using beam foil spectroscopic techniques. The measured values, derived from analysis of arbitrarily normalized decay curves, are presented and compared with theoretical calculations and previous measurements. Accurate probabilities have been determined by the well-known relationship.

  2. Neutronic Analyses in Support of the HFIR Beamline Modifications and Lifetime Extension

    Science.gov (United States)

    Remec, I.; Blakeman, E. D.

    2009-08-01

    At the High Flux Isotope Reactor, in operation since 1966 at the Oak Ridge National Laboratory, a larger HB-2 beam tube was installed to enhance capabilities for neutron science research. Neutronic analyses, including dosimetry measurements, radiation transport simulations, and simultaneous neutron and gamma spectrum adjustment calculations, performed to assess the impact of modifications on the PV lifetime are presented.

  3. Lifetime Studies of Cs2Te Cathodes at the Phin RF Photoinjector at CERN

    CERN Document Server

    Hessler, C; Divall Csatari, M; Doebert, S; Fedosseev, V

    2012-01-01

    The PHIN photoinjector has been developed to study the feasibility of a photoinjector option for the CLIC (Compact LInear Collider) drive beam as an alternative to the baseline design, using a thermionic gun. The CLIC drive beam requires a high charge of 8.4 nC per bunch in 0.14 ms long trains, with 2 ns bunch spacing and 50 Hz macro pulse repetition rate, which corresponds to a total charge per macro pulse of 0.59 mC. This means unusually high peak and average currents for photoinjectors and is challenging concerning the cathode lifetime. In this paper detailed studies of the lifetime of Cs2Te cathodes, produced by the co-evaporation technique, are presented with respect to bunch charge, train length and vacuum level. Furthermore, the impact of the train length and bunch charge on the vacuum level will be discussed and steps to extend the lifetime will be outlined.

  4. Inhomogeneous dephasing masks coherence lifetimes in ensemble measurements.

    Science.gov (United States)

    Pelzer, Kenley M; Griffin, Graham B; Gray, Stephen K; Engel, Gregory S

    2012-04-28

    An open question at the forefront of modern physical sciences is what role, if any, quantum effects may play in biological sensing and energy transport mechanisms. One area of such research concerns the possibility of coherent energy transport in photosynthetic systems. Spectroscopic evidence of long-lived quantum coherence in photosynthetic light-harvesting pigment protein complexes (PPCs), along with theoretical modeling of PPCs, has indicated that coherent energy transport might boost efficiency of energy transport in photosynthesis. Accurate assessment of coherence lifetimes is crucial for modeling the extent to which quantum effects participate in this energy transfer, because such quantum effects can only contribute to mechanisms proceeding on timescales over which the coherences persist. While spectroscopy is a useful way to measure coherence lifetimes, inhomogeneity in the transition energies across the measured ensemble may lead to underestimation of coherence lifetimes from spectroscopic experiments. Theoretical models of antenna complexes generally model a single system, and direct comparison of single system models to ensemble averaged experimental data may lead to systematic underestimation of coherence lifetimes, distorting much of the current discussion. In this study, we use simulations of the Fenna-Matthews-Olson complex to model single complexes as well as averaged ensembles to demonstrate and roughly quantify the effect of averaging over an inhomogeneous ensemble on measured coherence lifetimes. We choose to model the Fenna-Matthews-Olson complex because that system has been a focus for much of the recent discussion of quantum effects in biology, and use an early version of the well known environment-assisted quantum transport model to facilitate straightforward comparison between the current model and past work. Although ensemble inhomogeneity is known to lead to shorter lifetimes of observed oscillations (simply inhomogeneous spectral

  5. In-beam y-ray spectroscopy studies of medium-spin states in the odd-odd nucleus 186Re

    Energy Technology Data Exchange (ETDEWEB)

    Matters, D. A.; Kondev, F. G.; Aoi, N; Ayyad, Y.; Byrne, A. P.; Carpenter, M. P.; Carroll, J. J.; Chiara, C. J.; Davidson, P. M.; Dracoulis, G. D.; Hoffman, C. R.; Janssens, R. V. F.; Kay, B. P.; Lauritsen, T.; Zhu, S.

    2017-07-27

    Excited states in 186Re with spins up to J = 12~ were investigated in two separate experiments using 186W(d, 2n) reactions at beam energies of 12.5 MeV and 14.5 MeV. Two- and three-fold γ-ray coincidence data were collected using the CAESAR and CAGRA spectrometers, respectively, each composed of Compton-suppressed HpGe detectors. Analysis of the data revealed rotational bands built on several two-quasiparticle intrinsic states, including a long-lived Kπ = (8+) isomer. Configuration assignments were supported by an analysis of in-band properties, such as |gK − gR| values. The excitation energies of the observed intrinsic states were compared with results from multiquasiparticle blocking calculations, based on the Lipkin-Nogami pairing approach, that included contributions from the residual proton-neutron interactions.

  6. Computing lifetimes for battery-powered devices

    OpenAIRE

    Jongerden, Marijn; Haverkort, Boudewijn

    2010-01-01

    The battery lifetime of mobile devices depends on the usage pattern of the battery, next to the discharge rate and the battery capacity. Therefore, it is important to include the usage pattern in battery lifetime computations. We do this by combining a stochastic workload, modeled as a continuous-time Markov model, with a well-known battery model. For this combined model, we provide new algorithms to efficiently compute the expected lifetime and the distribution and expected value of the deli...

  7. Combined measurement of X-ray photon correlation spectroscopy and diffracted X-ray tracking using pink beam X-rays.

    Science.gov (United States)

    Shinohara, Yuya; Watanabe, Akira; Kishimoto, Hiroyuki; Amemiya, Yoshiyuki

    2013-09-01

    Combined X-ray photon correlation spectroscopy (XPCS) and diffracted X-ray tracking (DXT) measurements of carbon-black nanocrystals embedded in styrene-butadiene rubber were performed. From the intensity fluctuation of speckle patterns in a small-angle scattering region (XPCS), dynamical information relating to the translational motion can be obtained, and the rotational motion is observed through the changes in the positions of DXT diffraction spots. Graphitized carbon-black nanocrystals in unvulcanized styrene-butadiene rubber showed an apparent discrepancy between their translational and rotational motions; this result seems to support a stress-relaxation model for the origin of super-diffusive particle motion that is widely observed in nanocolloidal systems. Combined measurements using these two techniques will give new insights into nanoscopic dynamics, and will be useful as a microrheology technique.

  8. Nuclear moments, spins and charge radii of copper isotopes from N=28 to N=50 by collinear fast-beam laser spectroscopy

    CERN Multimedia

    2002-01-01

    We aim at establishing an unambiguous spin determination of the ground and isomeric states in the neutron rich Cu-isotopes from A=72 up to A=78 and to measure the magnetic and quadrupole moments between the N=28 and N=50 shell closures. This study will provide information on the double-magicity of $^{56}$Ni and $^{78}$Ni, both at the extremes of nuclear stability. It will provide evidence on the suggested inversion of ground state spin around A$\\approx$74, due to the monopole migration of the $\\pi f_{5/2}$ level. The collinear laser spectroscopy technique will be used, which furthermore provides information on the changes in mean square charge radii between both neutron shell closures, probing a possible onset of deformation in this region.

  9. Systems and methods for circuit lifetime evaluation

    Science.gov (United States)

    Heaps, Timothy L. (Inventor); Sheldon, Douglas J. (Inventor); Bowerman, Paul N. (Inventor); Everline, Chester J. (Inventor); Shalom, Eddy (Inventor); Rasmussen, Robert D. (Inventor)

    2013-01-01

    Systems and methods for estimating the lifetime of an electrical system in accordance with embodiments of the invention are disclosed. One embodiment of the invention includes iteratively performing Worst Case Analysis (WCA) on a system design with respect to different system lifetimes using a computer to determine the lifetime at which the worst case performance of the system indicates the system will pass with zero margin or fail within a predetermined margin for error given the environment experienced by the system during its lifetime. In addition, performing WCA on a system with respect to a specific system lifetime includes identifying subcircuits within the system, performing Extreme Value Analysis (EVA) with respect to each subcircuit to determine whether the subcircuit fails EVA for the specific system lifetime, when the subcircuit passes EVA, determining that the subcircuit does not fail WCA for the specified system lifetime, when a subcircuit fails EVA performing at least one additional WCA process that provides a tighter bound on the WCA than EVA to determine whether the subcircuit fails WCA for the specified system lifetime, determining that the system passes WCA with respect to the specific system lifetime when all subcircuits pass WCA, and determining that the system fails WCA when at least one subcircuit fails WCA.

  10. Experimentally Measured Radiative Lifetimes and Oscillator Strengths in Neutral Vanadium

    Science.gov (United States)

    Holmes, C. E.; Pickering, J. C.; Ruffoni, M. P.; Blackwell-Whitehead, R.; Nilsson, H.; Engström, L.; Hartman, H.; Lundberg, H.; Belmonte, M. T.

    2016-06-01

    We report a new study of the V i atom using a combination of time-resolved laser-induced fluorescence and Fourier transform spectroscopy that contains newly measured radiative lifetimes for 25 levels between 24,648 cm-1 and 37,518 cm-1 and oscillator strengths for 208 lines between 3040 and 20000 Å from 39 upper energy levels. Thirteen of these oscillator strengths have not been reported previously. This work was conducted independently of the recent studies of neutral vanadium lifetimes and oscillator strengths carried out by Den Hartog et al. and Lawler et al., and thus serves as a means to verify those measurements. Where our data overlap with their data, we generally find extremely good agreement in both level lifetimes and oscillator strengths. However, we also find evidence that Lawler et al. have systematically underestimated oscillator strengths for lines in the region of 9000 ± 100 Å. We suggest a correction of 0.18 ± 0.03 dex for these values to bring them into agreement with our results and those of Whaling et al. We also report new measurements of hyperfine structure splitting factors for three odd levels of V i lying between 24,700 and 28,400 cm-1.

  11. Ruby fluorescence lifetime measurements for temperature determinations at high (p, T)

    Science.gov (United States)

    Bauer, Johannes D.; Bayarjargal, Lkhamsuren; Winkler, Björn

    2012-06-01

    The lifetime of the ruby R1 fluorescence line was measured as a function of pressure (up to about 20 GPa) and temperature (550 K) in an externally heated diamond anvil cell (DAC). At constant temperatures, the lifetime is increasing linearly with increasing pressure. The slope of the pressure dependence is constant up to a temperature of 450 K and it is decreasing at higher temperatures. At constant pressure, the lifetime is exponentially decreasing with increasing temperature. The (p, T)-dependence can be parametrized by the combination of a linear and an exponential function. This allows an accurate p, T-determination by the combination of fluorescence spectroscopy using Sm2+-doped strontium tetraborate and lifetime measurements of ruby, as the energy of the Sm2+ fluorescence is nearly temperature-independent.

  12. Lifetime-Enhanced Transport in Silicon due to Spin and Valley Blockade

    NARCIS (Netherlands)

    Lansbergen, G.P.; Rahman, R.; Verduijn, J.; Tettamanzi, G.C.; Collaert, N.; Biesemans, S.; Klimeck, G.; Hollenberg, L.C.L.; Rogge, S.

    2011-01-01

    We report the observation of lifetime-enhanced transport (LET) based on perpendicular valleys in silicon by transport spectroscopy measurements of a two-electron system in a silicon transistor. The LET is manifested as a peculiar current step in the stability diagram due to a forbidden transition be

  13. Study on chemical reactions of isolated Mössbauer probes in solid gas matrices using in-beam Mössbauer spectroscopy

    Science.gov (United States)

    Tanigawa, S.; Kobayashi, Y.; Yamada, Y.; Mihara, M.; Kubo, M. K.; Miyazaki, J.; Sato, W.; Nagatomo, T.; Natori, D.; Sato, Y.; Sato, S.; Kitagawa, A.

    2016-12-01

    In-beam Mössbauer spectra of 57Fe after 57Mn ( T 1/2= 1.45 min) implantation into a CH 4 matrix and mixture matrices of CH 4 and Ar at 18 K were measured. The spectrum obtained in the CH 4 matrix was analyzed well with a doublet and a singlet peaks. These components were assigned to two constitutional isomers of Fe(CH 4)2+ as derived from density functional theory calculations and the Mössbauer parameters. In the case of the low concentration of CH 4 with an Ar matrix, the Fe + (3d 74s) in the excited state atomic configuration and Fe + (3d 64s 1) in the ground state were observed, as observed in our previous implantation experiment into Ar and Xe matrices. The formation yields of Fe(CH 4)2+ are discussed in term of the number of first-nearest-neighbor CH 4 molecules around an Fe + ion.

  14. Lifetime and g-factor measurements of excited states using Coulomb excitation and alpha transfer reactions

    Energy Technology Data Exchange (ETDEWEB)

    Guevara, Z. E., E-mail: zjguevaram@unal.edu.co; Torres, D. A., E-mail: datorresg@unal.edu.co [Physics Department, Universidad Nacional de Colombia, Bogotá D.C. (Colombia)

    2016-07-07

    In this contribution the challenges in the use of a setup to simultaneously measure lifetimes and g-factor values will be presented. The simultaneous use of the transient field technique and the Doppler Shift Attenuation Method, to measure magnetic moments and lifetimes respectively, allows to obtain a complete characterization of the currents of nucleons and the deformation in excited states close to the ground state. The technique is at the moment limited to Coulomb excitation and alpha-transfer reactions, what opens an interesting perspective to consider this type of experiments with radioactive beams. The use of deep-inelastic and fusion-evaporation reactions will be discussed. An example of a setup that makes use of a beam of {sup 106}Cd to study excited states of {sup 110}Sn and the beam nuclei itself will be presented.

  15. Beam Loss Monitors at the ESRF

    CERN Document Server

    Joly, B; Naylor, G A

    2000-01-01

    The European Synchrotron radiation facility is a third generation x-ray source providing x-rays on a continuous basis. As a facility available to external users, the monitoring of radiation caused by the loss of high-energy stored beam is of great concern. A network of beam loss monitors has been installed inside the storage ring tunnel so as to detect and localize the slow loss of electrons during a beam decay. This diagnostic tool allows optimization of beam parameters and physical aperture limits as well as giving useful information on the machine to allow the lifetime to be optimized and defects localized.

  16. Cosmology in Mr. Tompkins' Lifetime

    Science.gov (United States)

    Lindner, Rudi Paul

    2016-01-01

    Mr. Tompkins, the hero of George Gamow's most famous book, was born in the first decade of the twentieth century and lived until its end. A bank clerk by day, Mr. Tompkins had wide-ranging interests, and his curiosity led him to popular scientific presentations, and these in turn brought him a long and happy marriage to Maud, the daughter of a professor of physics. His lifetime offers an appropriate framework for a meditation on the history of cosmology during the century in which cosmology became a scientific enterprise. As it happens, Mr. Tompkins' first exposure to cosmology, in which he observed both the expansion and contraction of an oscillating universe in 1939, happened during the long night of relativity, the generation in which relativity specialists became few and, like the galaxies, far between. This talk will consider the heyday of early relativistic cosmology from 1917 to 1935, the causes and consequences of the "long night" from 1935 until 1963, and the renaissance of cosmology, which, occurring as it did upon the retirement of Mr. Tompkins, afforded him great pleasure in his later years.

  17. The Lifetime of Axion Stars

    CERN Document Server

    Eby, Joshua; Wijewardhana, L C R

    2015-01-01

    We investigate the decay of condensates of scalars in a field theory defined by $V({\\cal A})=m^2 f^2 [1-\\cos({\\cal A}/f)]$, where $m$ and $f$ are the mass and decay constant of the scalar field. An example of such a theory is that of the axion, in which case the condensates are called axion stars. The axion field, $\\cal A$, is self adjoint. As a result the axion number is not an absolutely conserved quantity. Therefore, axion stars are not stable and have finite lifetimes. Bound axions, localized on the volume of the star, have a coordinate uncertainty $\\Delta x \\sim R \\sim 1/(m_a \\Delta)$, where $R$ is the radius of the star and $\\Delta = \\sqrt{1-E_0^2/m_a^2}$. Here $m_a$ and $E_0$ are the mass and the ground state energy of the bound axion. Then the momentum distribution of axions has a width of $\\Delta p \\sim m_a\\Delta$. At strong binding, $\\Delta={\\cal O}(1)$, bound axions can easily transfer a sufficient amount of momentum to create and emit a free axion, leading to fast decay of the star with a transiti...

  18. Baselines for Lifetime of Organic Solar Cells

    DEFF Research Database (Denmark)

    Gevorgyan, Suren; Espinosa Martinez, Nieves; Ciammaruchi, Laura

    2016-01-01

    The process of accurately gauging lifetime improvements in organic photovoltaics (OPVs) or other similar emerging technologies, such as perovskites solar cells is still a major challenge. The presented work is part of a larger effort of developing a worldwide database of lifetimes that can help e...

  19. Computing lifetimes for battery-powered devices

    NARCIS (Netherlands)

    Jongerden, M.R.; Haverkort, Boudewijn R.H.M.

    The battery lifetime of mobile devices depends on the usage pattern of the battery, next to the discharge rate and the battery capacity. Therefore, it is important to include the usage pattern in battery lifetime computations. We do this by combining a stochastic workload, modeled as a

  20. Mean fluorescence lifetime and its error

    Energy Technology Data Exchange (ETDEWEB)

    Fiserova, Eva [Department of Mathematical Analysis and Applications of Mathematics, Faculty of Science, Palacky University in Olomouc, tr. 17. listopadu 12, CZE-77146 Olomouc (Czech Republic); Kubala, Martin, E-mail: mkubala@prfnw.upol.cz [Department of Biophysics, Faculty of Science, Palacky University in Olomouc, tr. 17. listopadu 12, CZE-77146 Olomouc (Czech Republic)

    2012-08-15

    Mean excited-state lifetime is one of the fundamental fluorescence characteristics and enters as an important parameter into numerous calculations characterizing molecular interactions, such as e.g. FRET or fluorescence quenching. Our experiments demonstrated that the intensity-weighted mean fluorescence lifetime is very robust characteristic, in contrast to the amplitude-weighted one, which value is dependent on the data quality and particularly on the used fitting model. For the first time, we also report the procedure for the error estimation for both the intensity- and amplitude-weighted mean fluorescence lifetimes. Furthermore, we present a method for estimation of the mean fluorescence lifetime directly from the fluorescence-decay curve recorded by TCSPC (Time-Correlated Single-Photon Counting) method. For its simplicity and low computational demands, it could be a useful tool in the high-throughput applications, such as FACS, FLIM-FRET or HPLC detectors. - Highlights: Black-Right-Pointing-Pointer Intensity-weighted mean fluorescence lifetime is very robust characteristic. Black-Right-Pointing-Pointer The amplitude-weighted mean lifetime depends on the selection of fitting model. Black-Right-Pointing-Pointer Rigorous procedure for estimation of confidence intervals for mean lifetime. Black-Right-Pointing-Pointer The mean lifetime can be estimated directly from the TCSPC histogram.

  1. Computing lifetimes for battery-powered devices

    NARCIS (Netherlands)

    Jongerden, Marijn; Haverkort, Boudewijn

    2010-01-01

    The battery lifetime of mobile devices depends on the usage pattern of the battery, next to the discharge rate and the battery capacity. Therefore, it is important to include the usage pattern in battery lifetime computations. We do this by combining a stochastic workload, modeled as a continuous-ti

  2. Stochastic Analysis of Orbital Lifetimes of Spacecraft

    Science.gov (United States)

    Sasamoto, Washito; Goodliff, Kandyce; Cornelius, David

    2008-01-01

    A document discusses (1) a Monte-Carlo-based methodology for probabilistic prediction and analysis of orbital lifetimes of spacecraft and (2) Orbital Lifetime Monte Carlo (OLMC)--a Fortran computer program, consisting of a previously developed long-term orbit-propagator integrated with a Monte Carlo engine. OLMC enables modeling of variances of key physical parameters that affect orbital lifetimes through the use of probability distributions. These parameters include altitude, speed, and flight-path angle at insertion into orbit; solar flux; and launch delays. The products of OLMC are predicted lifetimes (durations above specified minimum altitudes) for the number of user-specified cases. Histograms generated from such predictions can be used to determine the probabilities that spacecraft will satisfy lifetime requirements. The document discusses uncertainties that affect modeling of orbital lifetimes. Issues of repeatability, smoothness of distributions, and code run time are considered for the purpose of establishing values of code-specific parameters and number of Monte Carlo runs. Results from test cases are interpreted as demonstrating that solar-flux predictions are primary sources of variations in predicted lifetimes. Therefore, it is concluded, multiple sets of predictions should be utilized to fully characterize the lifetime range of a spacecraft.

  3. Lifetime of Organic Photovoltaics: Status and Predictions

    DEFF Research Database (Denmark)

    Gevorgyan, Suren; Madsen, Morten Vesterager; Roth, Bérenger

    2016-01-01

    The results of a meta-analysis conducted on organic photovoltaics (OPV) lifetime data reported in the literature is presented through the compilation of an extensive OPV lifetime database based on a large number of articles, followed by analysis of the large body of data. We fully reveal the prog...

  4. Development of a high average current polarized electron source with long cathode operational lifetime

    Directory of Open Access Journals (Sweden)

    C. K. Sinclair

    2007-02-01

    Full Text Available Substantially more than half of the electromagnetic nuclear physics experiments conducted at the Continuous Electron Beam Accelerator Facility of the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory require highly polarized electron beams, often at high average current. Spin-polarized electrons are produced by photoemission from various GaAs-based semiconductor photocathodes, using circularly polarized laser light with photon energy slightly larger than the semiconductor band gap. The photocathodes are prepared by activation of the clean semiconductor surface to negative electron affinity using cesium and oxidation. Historically, in many laboratories worldwide, these photocathodes have had short operational lifetimes at high average current, and have often deteriorated fairly quickly in ultrahigh vacuum even without electron beam delivery. At Jefferson Lab, we have developed a polarized electron source in which the photocathodes degrade exceptionally slowly without electron emission, and in which ion back bombardment is the predominant mechanism limiting the operational lifetime of the cathodes during electron emission. We have reproducibly obtained cathode 1/e dark lifetimes over two years, and 1/e charge density and charge lifetimes during electron beam delivery of over 2×10^{5}   C/cm^{2} and 200 C, respectively. This source is able to support uninterrupted high average current polarized beam delivery to three experimental halls simultaneously for many months at a time. Many of the techniques we report here are directly applicable to the development of GaAs photoemission electron guns to deliver high average current, high brightness unpolarized beams.

  5. Beam instability Workshop - plenary sessions

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The purpose of this workshop was to provide a review of the mechanisms of limiting beam instabilities, their cures, including feedback, and beam measurement for synchrotron radiation light sources. 12 plenary sessions took place whose titles are: 1) challenging brilliance and lifetime issues with increasing currents; 2) limiting instabilities in multibunch; 3) experience from high currents in B factories; 4) longitudinal dynamics in high intensity/bunch; 5) Transverse instabilities for high intensity/bunch; 6) working group introduction from ESRF experience; 7) impedance modelling: simulations, minimization; 8) report on the broadband impedance measurements and modelling workshop; 9) feedback systems for synchrotron light sources; 10) beam instabilities diagnostics; 11) harmonic cavities: the pros and cons; and 12) experimental study of fast beam-ion instabilities at PLS. This document gathers the 12 articles that were presented during these sessions.

  6. Modelling lifetime data with multivariate Tweedie distribution

    Science.gov (United States)

    Nor, Siti Rohani Mohd; Yusof, Fadhilah; Bahar, Arifah

    2017-05-01

    This study aims to measure the dependence between individual lifetimes by applying multivariate Tweedie distribution to the lifetime data. Dependence between lifetimes incorporated in the mortality model is a new form of idea that gives significant impact on the risk of the annuity portfolio which is actually against the idea of standard actuarial methods that assumes independent between lifetimes. Hence, this paper applies Tweedie family distribution to the portfolio of lifetimes to induce the dependence between lives. Tweedie distribution is chosen since it contains symmetric and non-symmetric, as well as light-tailed and heavy-tailed distributions. Parameter estimation is modified in order to fit the Tweedie distribution to the data. This procedure is developed by using method of moments. In addition, the comparison stage is made to check for the adequacy between the observed mortality and expected mortality. Finally, the importance of including systematic mortality risk in the model is justified by the Pearson's chi-squared test.

  7. The lifetime of axion stars

    Science.gov (United States)

    Eby, Joshua; Suranyi, Peter; Wijewardhana, L. C. R.

    2016-05-01

    We investigate the decay of condensates of scalars in a field theory defined by V (𝒜) = m2f2[1 -cos(𝒜/f)], where m and f are the mass and decay constant of the scalar field. An example of such a theory is that of the axion, in which case the condensates are called axion stars. The axion field, 𝒜, is self-adjoint. As a result, the axion number is not an absolutely conserved quantity. Therefore, axion stars are not stable and have finite lifetimes. Bound axions, localized on the volume of the star, have a coordinate uncertainty δx ˜ R ˜ 1/(maΔ), where R is the radius of the star and Δ = 1 - E0 2/ma 2. Here ma and E0 are the mass, and the ground state energy of the bound axion. Then the momentum distribution of axions has a width of δp ˜ maΔ. At strong binding, Δ = 𝒪(1), bound axions can easily transfer a sufficient amount of momentum to create and emit a free axion, leading to fast decay of the star with a transition rate Γ ˜ ma. However, when Δ ≪ 1, the momentum distribution is more restricted, and as shown in this paper, the transition rate for creating a free axion decreases as exp(-pδx) ˜exp(-Δ-1). Then sufficiently large, weakly bound axion stars, produced after the Big Bang, survive until the present time. We plot the region of their stability, limited by decay through axion loss and by gravitational instability, as a function of the mass of the axion and the mass of the star.

  8. Lifetime experimental study of graphite cathode for relativistic backward wave oscillator

    Science.gov (United States)

    Wu, Ping; Sun, Jun; Chen, Changhua

    2016-07-01

    Graphite cathodes are widely used due to their good emission properties, especially their long lifetime. Some previous papers have researched their lifetime under certain conditions and uncovered some important phenomena. This paper is dedicated to research the lifetime of the graphite cathode under higher power. In the lifetime test, the voltage and current amplitudes are about 970 kV and 9.7 kA, respectively. The repetition rate is 20 Hz. An X-band relativistic backward wave oscillator is used to generate high power microwave by utilizing the electron beam energy. The experimental results demonstrate that the emission property of the graphite cathode remains quite stable during 105 pulses, despite some slight deteriorations regarding the beam and microwave parameters. The macroscopic morphology change of the cathode blade due to material evaporation is observed by a laser microscope. The mass loss of the graphite cathode is about 60 μg/C. Meanwhile, the observation by a scanning electron microscope uncovers that the original numerous flaky micro-structures are totally replaced by a relatively smooth surface at the mid region of the cathode blade and a large number of new micro-protrusions at the blade edges during the lifetime test.

  9. Optical and microstructural characterization of porous silicon using photoluminescence, SEM and positron annihilation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, C K [Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong (China); Nahid, F [Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong (China); Cheng, C C [Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong (China); Beling, C D [Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong (China); Fung, S [Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong (China); Ling, C C [Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong (China); Djurisic, A B [Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong (China); Pramanik, C [Department of Electronics and Telecommunication Engineering, Jadavpur University, Kolkata 700032 (India); Saha, H [Department of Electronics and Telecommunication Engineering, Jadavpur University, Kolkata 700032 (India); Sarkar, C K [Department of Electronics and Telecommunication Engineering, Jadavpur University, Kolkata 700032 (India)

    2007-12-05

    We have studied the dependence of porous silicon morphology and porosity on fabrication conditions. N-type (100) silicon wafers with resistivity of 2-5 {omega} cm were electrochemically etched at various current densities and anodization times. Surface morphology and the thickness of the samples were examined by scanning electron microscopy (SEM). Detailed information of the porous silicon layer morphology with variation of preparation conditions was obtained by positron annihilation spectroscopy (PAS): the depth-defect profile and open pore interconnectivity on the sample surface has been studied using a slow positron beam. Coincidence Doppler broadening spectroscopy (CDBS) was used to study the chemical environment of the samples. The presence of silicon micropores with diameter varying from 1.37 to 1.51 nm was determined by positron lifetime spectroscopy (PALS). Visible luminescence from the samples was observed, which is considered to be a combination effect of quantum confinement and the effect of Si = O double bond formation near the SiO{sub 2}/Si interface according to the results from photoluminescence (PL) and positron annihilation spectroscopy measurements. The work shows that the study of the positronium formed when a positron is implanted into the porous surface provides valuable information on the pore distribution and open pore interconnectivity, which suggests that positron annihilation spectroscopy is a useful tool in the porous silicon micropores' characterization.

  10. Nuclear Power Plant Lifetime Management Study (I)

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sung Yull; Jeong, Ill Seok; Jang, Chang Heui; Song, Taek Ho; Song, Woo Young [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Jin, Tae Eun [Korea Power Engineering Company Consulting and Architecture Engineers, (Korea, Republic of); Kim, Woo Chul [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1996-12-31

    As the operation-year of nuclear power plant increases and finding sites for new nuclear power plant becomes harder, a comprehensive and systematic nuclear plant lifetime management(PLIM) program including life extension has to be established for stable and safe supply of electricity. A feasibility study was conducted to systematically evaluate technical, economic and regulatory aspect of plant lifetime managements and plant life extension for Kori-1 nuclear power plant. For technical evaluation of nuclear power plant, 13 major components were selected for lifetime evaluation by screening system. structure, and components(SSCs) of the plant. It was found that except reactor pressure vessel, which needs detailed integrity analysis, and low pressure turbine, which is scheduled to be replaced, 11 out of 13 major components have sufficient service life, for more than 40 years. Because domestic rules and regulations related to license renewal has not yet been written, review on the regulatory aspect of life extensions was conducted using US NRC rules and regulations. A cooperative effort with nuclear regulatory body is needed for early completion of license renewal rules and regulations. For economic evaluation of plant lifetime extension, a computer program was developed and used. It was found that 10 to 20 year of extension operation of Kori-1 nuclear power plant was proved. Based on the results, next phase of plant lifetime management program for detailed lifetime evaluation and presenting detailed implementation schedule for plant refurbishment for lifetime extension should be followed. (author). 74 refs., figs.

  11. Determination of minority-carrier lifetime and surface recombination velocity with high spacial resolution

    Science.gov (United States)

    Watanabe, M.; Actor, G.; Gatos, H. C.

    1977-01-01

    Quantitative analysis of the electron beam induced current in conjunction with high-resolution scanning makes it possible to evaluate the minority-carrier lifetime three dimensionally in the bulk and the surface recombination velocity two dimensionally, with a high spacial resolution. The analysis is based on the concept of the effective excitation strength of the carriers which takes into consideration all possible recombination sources. Two-dimensional mapping of the surface recombination velocity of phosphorus-diffused silicon diodes is presented as well as a three-dimensional mapping of the changes in the minority-carrier lifetime in ion-implanted silicon.

  12. Long Lifetime Hole Traps at Grain Boundaries in CdTe Thin-Film Photovoltaics

    Science.gov (United States)

    Mendis, B. G.; Gachet, D.; Major, J. D.; Durose, K.

    2015-11-01

    A novel time-resolved cathodoluminescence method, where a pulsed electron beam is generated via the photoelectric effect, is used to probe individual CdTe grain boundaries. Excitons have a short lifetime (≤100 ps ) within the grains and are rapidly quenched at the grain boundary. However, a ˜47 meV shallow acceptor, believed to be due to oxygen, can act as a long lifetime hole trap, even at the grain boundaries where their concentration is higher. This provides direct evidence supporting recent observations of hopping conduction across grain boundaries in highly doped CdTe at low temperature.

  13. Models for Battery Reliability and Lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Smith, K.; Wood, E.; Santhanagopalan, S.; Kim, G. H.; Neubauer, J.; Pesaran, A.

    2014-03-01

    Models describing battery degradation physics are needed to more accurately understand how battery usage and next-generation battery designs can be optimized for performance and lifetime. Such lifetime models may also reduce the cost of battery aging experiments and shorten the time required to validate battery lifetime. Models for chemical degradation and mechanical stress are reviewed. Experimental analysis of aging data from a commercial iron-phosphate lithium-ion (Li-ion) cell elucidates the relative importance of several mechanical stress-induced degradation mechanisms.

  14. Family of lifetime sensors for medical purposes

    Science.gov (United States)

    Lippitsch, Max E.; Draxler, Sonja

    1995-05-01

    A family of indicators has been developed for fluorescence lifetime-based measurement of oxygen, pH, carbon dioxide, and potassium, all the indicators being derivatives of the same chemical compound and having identical spectral and lifetime properties. The indicators show an absorption accessible to low- cast light sources, a large Stokes shift, and long fluorescence decay time. all indicators can be excited at the same excitation wavelength, monitored at the same emission wavelength, and measured within the same time range. This opens the possibility of building a compact lifetime-based instrument to simultaneously measure blood gases and cations.

  15. Lifetimes and configuration mixing in 110Cd

    Science.gov (United States)

    Lobach, Yu. N.; Efimov, A. D.; Pasternak, A. A.

    Lifetimes of excited states in 110Cd have been measured by the Doppler shift attenuation method in the reaction (α,2nγ) at Eα= 25 MeV. Lifetime values for 8 states and lifetime limits for 3 states were obtained. The band structures of 110Cd have been interpreted in terms of a modified version of the interacting boson model (IBM + 2 q.p.). The calculations explain well the excitation energies and electromagnetic transition probabilities up to Jπ= 16+, except for the 10+1 state. The structural features are discussed in terms of collective and two quasiparticle excitations.

  16. Statistical Models and Methods for Lifetime Data

    CERN Document Server

    Lawless, Jerald F

    2011-01-01

    Praise for the First Edition"An indispensable addition to any serious collection on lifetime data analysis and . . . a valuable contribution to the statistical literature. Highly recommended . . ."-Choice"This is an important book, which will appeal to statisticians working on survival analysis problems."-Biometrics"A thorough, unified treatment of statistical models and methods used in the analysis of lifetime data . . . this is a highly competent and agreeable statistical textbook."-Statistics in MedicineThe statistical analysis of lifetime or response time data is a key tool in engineering,

  17. Development and application of the intense slow positron beam at IHEP

    Institute of Scientific and Technical Information of China (English)

    WANG Bao-Yi; MA Yan-Yun; WANG Ping; CAO Xing-Zhong; QIN Xiu-So; ZHANG Zhe; YU Run-Sheng; WEI Long

    2008-01-01

    This paper describes the development and application of an intense slow positron beam at IHEP with regard to its two main components.The Variable-Energy Positron Lifetime Spectroscopy (VEPLS) based on the pulsing system consisting of a chopper,a prebuncher and a buncher has been constructed in order to meet the needs of materials science development.At present,the time resolution of the VEPLS can easily reach about 386 ps with a peak-to-background ratio of about 600:1.A plugged-in 22Na positron source section for adjusting the newly built experimental station and for increasing the beam operation efficiency has been constructed.A slow positron beam with an intensity of 2.5x105 e+/s and the beam profile whose diameter is 10 mm has been obtained;the moderation efficiency of the tungsten mesh moderator reaches 5.1x 10-4 as calculated with an original positron source activity of 52 mCi.

  18. Intense electron beams from GaAs photocathodes as a tool for molecular and atomic physics

    Energy Technology Data Exchange (ETDEWEB)

    Krantz, Claude

    2009-10-28

    We present cesium-coated GaAs photocathodes as reliable sources of intense, quasi-monoenergetic electron beams in atomic and molecular physics experiments. In long-time operation of the Electron Target of the ion storage ring TSR in Heidelberg, cold electron beams could be realised at steadily improving intensity and reliability. Minimisation of processes degrading the quantum efficiency allowed to increase the extractable current to more than 1mA at usable cathode lifetimes of 24 h or more. The benefits of the cold electron beam with respect to its application to electron cooling and electron-ion recombination experiments are discussed. Benchmark experiments demonstrate the superior cooling force and energy resolution of the photoelectron beam compared to its thermionic counterparts. The long period of operation allowed to study the long-time behaviour of the GaAs samples during multiple usage cycles at the Electron Target and repeated in-vacuum surface cleaning by atomic hydrogen exposure. An electron emission spectroscopy setup has been implemented at the photocathode preparation chamber of the Electron Target. Among others, this new facility opened the way to a novel application of GaAs (Cs) photocathodes as robust, ultraviolet-driven electron emitters. Based on this principle, a prototype of an electron gun, designed for implementation at the HITRAP setup at GSI, has been built and taken into operation successfully. (orig.)

  19. Charge and fluence lifetime measurements of a dc high voltage GaAs photogun at high average current

    Energy Technology Data Exchange (ETDEWEB)

    J. Grames, R. Suleiman, P.A. Adderley, J. Clark, J. Hansknecht, D. Machie, M. Poelker, M.L. Stutzman

    2011-04-01

    GaAs-based dc high voltage photoguns used at accelerators with extensive user programs must exhibit long photocathode operating lifetime. Achieving this goal represents a significant challenge for proposed high average current facilities that must operate at tens of milliamperes or more. This paper describes techniques to maintain good vacuum while delivering beam, and techniques that minimize the ill effects of ion bombardment, the dominant mechanism that reduces photocathode yield of a GaAs-based dc high voltage photogun. Experimental results presented here demonstrate enhanced lifetime at high beam currents by: (a) operating with the drive laser beam positioned away from the electrostatic center of the photocathode, (b) limiting the photocathode active area to eliminate photoemission from regions of the photocathode that do not support efficient beam delivery, (c) using a large drive laser beam to distribute ion damage over a larger area, and (d) by applying a relatively low bias voltage to the anode to repel ions created within the downstream beam line. A combination of these techniques provided the best total charge extracted lifetimes in excess of 1000 C at dc beam currents up to 9.5 mA, using green light illumination of bulk GaAs inside a 100 kV photogun.

  20. Hypernuclear spectroscopy of products from 6Li projectiles on a carbon target at 2 AGeV

    CERN Document Server

    Rappold, C; Nakajima, D; Saito, T R; Bertini, O; Bianchin, S; Bozkurt, V; Kavatsyuk, M; Ma, Y; Maas, F; Minami, S; Özel-Tashenov, B; Yoshida, K; Achenbach, P; Ajimura, S; Aumann, T; Gayoso, C Ayerbe; Bhang, H C; Caesar, C; Erturk, S; Fukuda, T; Göküzüm, B; Guliev, E; Hiraiwa, T; Hoffmann, J; Ickert, G; Ketenci, Z S; Khaneft, D; Kim, M; Kim, S; Koch, K; Kurz, N; Fèvre, A Le; Mizoi, Y; Moritsu, M; Nagae, T; Nungesser, L; Okamura, A; Ott, W; Pochodzalla, J; Sakaguchi, A; Sako, M; Schmidt, C J; Sekimoto, M; Simon, H; Sugimura, H; Takahashi, T; Tambave, G J; Tamura, H; Trautmann, W; Voltz, S; Yokota, N; Yoon, C J

    2013-01-01

    A novel experiment, aiming at demonstrating the feasibility of hypernuclear spectroscopy with heavy-ion beams, was conducted. Using the invariant mass method, the spectroscopy of hypernuclear products of 6Li projectiles on a carbon target at 2 AGeV was performed. Signals of the \\Lambda-hyperon and 3\\Lambda H and 4\\Lambda H hypernuclei were observed for final states of p+\\pi^-, 3He+\\pi^- and 4He+\\pi^-, respectively, with significance values of 6.7, 4.7 and 4.9\\sigma. By analyzing the proper decay time from secondary vertex distribution with the unbinned maximum likelihood fitting method, their lifetime values were deduced to be $262 ^{+56}_{-43} \\pm 45$ ps for \\Lambda, $183 ^{+42}_{-32} \\pm 37$ ps for 3\\Lambda H, and $140 ^{+48}_{-33}\\pm 35 $ ps for 4\\Lambda H.

  1. Molecular orbital imaging of the acetone S2 excited state using time-resolved (e, 2e) electron momentum spectroscopy.

    Science.gov (United States)

    Yamazaki, Masakazu; Oishi, Keiya; Nakazawa, Hiroyuki; Zhu, Chaoyuan; Takahashi, Masahiko

    2015-03-13

    We report a time-resolved (e, 2e) experiment on the deuterated acetone molecule in the S2 Rydberg state with a lifetime of 13.5 ps. The acetone S2 state was prepared by a 195 nm pump laser and probed with electron momentum spectroscopy using a 1.2 keV incident electron beam of 1 ps temporal width. In spite of the low data statistics as well as of the limited time resolution (±35  ps) due to velocity mismatch, the experimental results clearly demonstrate that electron momentum spectroscopy measurements of short-lived transient species are feasible, opening the door to time-resolved orbital imaging in momentum space.

  2. Remote UV Fluorescence Lifetime Spectrometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this project is to develop, demonstrate, and deliver to NASA an innovative, portable, and power efficient Remote UV Fluorescence Lifetime Spectrometer...

  3. Enhancement of Photoluminescence Lifetime of ZnO Nanorods Making Use of Thiourea

    OpenAIRE

    Erdal Sönmez; Kadem Meral

    2012-01-01

    We have investigated correlation of photoluminescence lifetime between zinc oxide (ZnO) nanorods and thiourea-doped ZnO nanorods (tu: CH4N2S). Aqueous solutions of ZnO nanorods were deposited on glass substrate by using pneumatic spray pyrolysis technique. The as-prepared specimens were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and time-resolved photoluminescence spectroscopy (TRPL). The photoluminescence lifetime of ZnO nanorods and ZnO nanorods containing...

  4. The total lifetime costs of smoking

    DEFF Research Database (Denmark)

    Rasmussen, Gitte Susanne; Prescott, Eva; Sørensen, Thorkild I A;

    2004-01-01

    Net costs of smoking in a lifetime perspective and, hence, the economic interests in antismoking policies have been questioned. It has been proposed that the health-related costs of smoking are balanced by smaller expenditure due to shorter life expectancy.......Net costs of smoking in a lifetime perspective and, hence, the economic interests in antismoking policies have been questioned. It has been proposed that the health-related costs of smoking are balanced by smaller expenditure due to shorter life expectancy....

  5. Lifetime measurement in {sup 195}Po

    Energy Technology Data Exchange (ETDEWEB)

    Grahn, T.; Page, R.D. [University of Liverpool, Department of Physics, Oliver Lodge Laboratory, Liverpool (United Kingdom); Dewald, A.; Jolie, J.; Melon, B.; Pissulla, T. [Universitaet zu Koeln, Institut fuer Kernphysik, Koeln (Germany); Greenlees, P.T.; Jakobsson, U.; Jones, P.; Julin, R.; Juutinen, S.; Ketelhut, S.; Leino, M.; Nyman, M.; Peura, P.; Rahkila, P.; Saren, J.; Scholey, C.; Sorri, J.; Uusitalo, J. [University of Jyvaeskylae, Department of Physics, P.O. Box 35, Jyvaeskylae (Finland); Kroell, T.; Kruecken, R.; Maierbeck, P. [TU Muenchen, Physik-Department E12, Garching (Germany)

    2009-03-15

    The lifetime of the 17/2{sup +} yrast state in {sup 195}Po has been measured using the recoil distance Doppler-shift technique to be {tau}=43(11) ps. The lifetime was extracted from the singles {gamma}-ray spectra obtained by using the recoil-decay tagging method. The present work provides more information of the coupling schemes, shapes and configuration mixing in neutron-deficient odd-mass Po nuclei. (orig.)

  6. 14th international symposium on molecular beams

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    This report discusses research being conducted with molecular beams. The general topic areas are as follows: Clusters I; reaction dynamics; atomic and molecular spectroscopy; clusters II; new techniques; photodissociation dynamics; and surfaces.

  7. 14th international symposium on molecular beams

    Energy Technology Data Exchange (ETDEWEB)

    1992-09-01

    This report discusses research being conducted with molecular beams. The general topic areas are as follows: Clusters I; reaction dynamics; atomic and molecular spectroscopy; clusters II; new techniques; photodissociation & dynamics; and surfaces.

  8. Positron annihilation lifetime study of polyvinylpyrrolidone for nanoparticle-stabilizing pharmaceuticals.

    Science.gov (United States)

    Shpotyuk, O; Bujňáková, Z; Baláž, P; Ingram, A; Shpotyuk, Y

    2016-01-01

    Positron annihilation lifetime spectroscopy was applied to characterize free-volume structure of polyvinylpyrrolidone used as nonionic stabilizer in the production of many nanocomposite pharmaceuticals. The polymer samples with an average molecular weight of 40,000 g mol(-1) were pelletized in a single-punch tableting machine under an applied pressure of 0.7 GPa. Strong mixing in channels of positron and positronium trapping were revealed in the polyvinylpyrrolidone pellets. The positron lifetime spectra accumulated under normal measuring statistics were analysed in terms of unconstrained three- and four-term decomposition, the latter being also realized under fixed 0.125 ns lifetime proper to para-positronium self-annihilation in a vacuum. It was shown that average positron lifetime extracted from each decomposition was primary defined by long-lived ortho-positronium component. The positron lifetime spectra treated within unconstrained three-term fitting were in obvious preference, giving third positron lifetime dominated by ortho-positronium pick-off annihilation in a polymer matrix. This fitting procedure was most meaningful, when analysing expected positron trapping sites in polyvinylpyrrolidone-stabilized nanocomposite pharmaceuticals.

  9. Doppler-shift attenuation lifetime measurement of the 36Ar21+ level

    Science.gov (United States)

    Voss, P.; Drake, T. E.; Starosta, K.; Andreoiu, C.; Ashley, R.; Ball, G. C.; Bender, P. C.; Chester, A.; Churchman, R.; Cross, D. S.; Garnsworthy, A. B.; Hackman, G.; Hadinia, B.; Henderson, R.; Jigmeddorj, B.; Ketelhut, S.; Krücken, R.; Laffoley, A. T.; Leach, K. G.; Miller, D.; Orlandi, R.; Pearson, C. J.; Pore, J.; Rajabali, M. M.; Rand, E. T.; Svensson, C. E.; Tardiff, E.; Unsworth, C.; Wang, Z.-M.; Signoracci, A.

    2017-08-01

    At TRIUMF, the TIGRESS Integrated Plunger device and its suite of ancillary detector systems have been implemented for charged-particle tagging and light-ion identification in coincidence with γ -ray spectroscopy for Doppler-shift lifetime studies and low-energy Coulomb excitation measurements. As a test of the device, the lifetime of the first 2+ excited state in 36Ar was measured from the γ -ray line shape of the 21+→0g.s . + transition using the Doppler-shift attenuation technique following Coulomb excitation. The line-shape signatures, vital for precision lifetime measurements, were significantly improved by enhanced reaction-channel selectivity using a complementary approach of kinematic gating and digital rise-time discrimination of recoiling charged particles in a silicon PIN diode array. The lifetime was determined by comparisons between the data and simulated line shapes generated using our TIGRESS Coulomb excitation code as an input to the Lindhard method, which was then extended and included as a class in geant4. The model-independent lifetime result of 490 ±50 fs corresponds to a reduced quadrupole transition strength of B (E 2 ;21+→0g.s . +) =56 ±6 e2fm4 and agrees well with previous intermediate energy Coulomb excitation measurements, thereby resolving reported discrepancies in the 21+ level lifetime in this self-conjugate nucleus.

  10. Enhancement of Photoluminescence Lifetime of ZnO Nanorods Making Use of Thiourea

    Directory of Open Access Journals (Sweden)

    Erdal Sönmez

    2012-01-01

    Full Text Available We have investigated correlation of photoluminescence lifetime between zinc oxide (ZnO nanorods and thiourea-doped ZnO nanorods (tu: CH4N2S. Aqueous solutions of ZnO nanorods were deposited on glass substrate by using pneumatic spray pyrolysis technique. The as-prepared specimens were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, and time-resolved photoluminescence spectroscopy (TRPL. The photoluminescence lifetime of ZnO nanorods and ZnO nanorods containing thiourea was determined as =1.56±0.05 ns (2=0.9 and =2.12±0.03 ns (2=1.0, respectively. The calculated lifetime values of ZnO nanorods revealed that the presence of thiourea in ZnO nanorods resulted in increasing the exciton lifetime. In addition to the optical quality of ZnO nanorods, their exciton lifetime is comparable to the longest lifetimes reported for ZnO nanorods. The structural improvement of ZnO nanorods, containing thiourea, was also elucidated by taking their SEM images which show the thinner and longer ZnO nanorods compared to those without thiourea.

  11. Molecular ion photofragment spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bustamente, S.W.

    1983-11-01

    A new molecular ion photofragment spectrometer is described which features a supersonic molecular beam ion source and a radio frequency octapole ion trap interaction region. This unique combination allows several techniques to be applied to the problem of detecting a photon absorption event of a molecular ion. In particular, it may be possible to obtain low resolution survey spectra of exotic molecular ions by using a direct vibrational predissociation process, or by using other more indirect detection methods. The use of the spectrometer is demonstrated by measuring the lifetime of the O/sub 2//sup +/(/sup 4/..pi../sub u/) metastable state which is found to consist of two main components: the /sup 4/..pi../sub 5/2/ and /sup 4/..pi../sub -1/2/ spin components having a long lifetime (approx. 129 ms) and the /sup 4/..pi../sub 3/2/ and /sup 4/..pi../sub 1/2/ spin components having a short lifetime (approx. 6 ms).

  12. Neutron Lifetime Measurement Using Magnetically Trapped Ultracold Neutrons

    Science.gov (United States)

    Huffer, Craig; Huffman, P. R.; Schelhammer, K. W.; Dewey, M. S.; Huber, M. G.; Hughes, P. P.; Mumm, H. P.; Thompson, A. K.; Coakley, K.; Yue, A. T.; O'Shaughnessy, C. M.

    2017-01-01

    The neutron beta-decay lifetime is important in both nuclear astrophysics and in understanding weak interactions in the framework of the Standard Model. An experiment based at the NIST Center for Neutron Research was designed to address statistical and systematic limitations of former measurements. In our approach, a beam of 0.89 nm neutrons is incident on a superfluid 4He target within the minimum field region of an Ioffe-type magnetic trap. Some of the neutrons are subsequently downscattered by single phonons in the helium to low energies (decays the energetic electron produces a scintillation signal in the helium that is detected in real time using photomultiplier tubes. The current measurement is limited by larger than expected systematic corrections. We will discuss the result of the latest dataset and comment on the potential of future measurements.

  13. Study of neutron-rich nuclei structure around the N=28 shell closure using the in-beam gamma spectroscopy technique; Etude de la structure des noyaux riches en neutrons autour de la fermeture de couches N=28 par spectroscopie gamma en ligne

    Energy Technology Data Exchange (ETDEWEB)

    Bastin, B

    2007-10-15

    For a few years now, a loss of magicity in neutron-rich nuclei near the neutron drip-line at N=28 has been suggested and observed. Deformation in these nuclei has been observed. The deformation was explained in S isotopes as being due to a moderate reduction of the N=28 shell closure together with a proton induced collectivity originating from the near degeneracy of the proton d3/2 and s1/2 orbitals. As a consequence, the observed deformation seems to result from a subtle interplay between neutron and proton excitations. Since the proton configuration in the Si isotopes is expected to be more stable due to the Z=14 sub-shell gap, {sup 42}Si was considered as a key nucleus in order to distinguish the different effects responsible for the structural changes observed at N=28. Even if it is at the limits of our technical possibilities, an in-beam gamma-spectroscopy experiment using two-step fragmentation and one or several nucleons knockout reaction mechanisms was performed at GANIL. The measurement of the energy of the first excited state in {sup 42}Si, combined with the observation of {sup 38,40}Si and the spectroscopy of {sup 41,43}P, has given evidence for the loss of magicity at N=28 far from stability. Modifications of the effective interaction used in modern shell model calculations have been completed following this investigation, increasing its predictive character. This study confirms the role of the tensor force and the density dependence of the spin-orbit interaction in the collapse of the N=28 shell closure. (author)

  14. Development of pulsed positron beam line with compact pulsing system

    Energy Technology Data Exchange (ETDEWEB)

    Maekawa, Masaki, E-mail: maekawa.masaki@jaea.go.jp [Advanced Science Research Center, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Kawasuso, Atsuo [Advanced Science Research Center, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

    2012-01-01

    We have developed a pulsed slow positron beam with a pulse width of less than 200 ps and a period of 25 ns. The beam apparatus is composed of a Munich-type pre-buncher, a chopper and a buncher. Instead of the conventional RF cavity, a simple double-cylinder electrode is used for the buncher. The beam will be used for positron lifetime measurements. The time resolution of the whole system including lifetime measurement circuits is 250 ps, which is adequate for studying semiconductors and metals.

  15. Spectroscopy of neutral radium

    Energy Technology Data Exchange (ETDEWEB)

    Mol, Aran; De, Subhadeep; Jungmann, Klaus; Wilschut, Hans; Willmann, Lorenz [KVI, University of Groningen, Groningen (Netherlands)

    2008-07-01

    The heavy alkaline earth atoms radium is uniquely sensitive towards parity and time reversal symmetry violations due to a large enhancement of an intrinsic permanent electric dipole moment of the nucleous or the electron. Furthermore, radium is sensitive to atomic parity violation and the nuclear anapole moment. To prepare such experiments spectroscopy of relevant atomic states need to be done. At a later stage we will build a neutral atom trap for radium. We have built an atomic beam of the short lived isotope {sup 225}Ra with a flux of several 10{sup 4} atoms/sec. We are preparing the laser spectroscopy using this beam setup. In the preparation for efficient laser cooling and trapping we have successfully trapped barium, which is similar in it's requirements for laser cooling. The techniques which we have developed with barium can be used to trap rare radium isotopes. We report on the progress of the experiments.

  16. Lifetime measurements in shape transition nucleus {sup 188}Pt

    Energy Technology Data Exchange (ETDEWEB)

    Rohilla, Aman; Gupta, C.K.; Chamoli, S.K. [University of Delhi, Department of Physics and Astrophysics, New Delhi (India); Singh, R.P.; Muralithar, S. [Inter University Accelerator Centre, New Delhi (India); Chakraborty, S.; Sharma, H.P. [Banaras Hindu University, Department of Physics, Varanasi (India); Kumar, A.; Govil, I.M. [Panjab University, Department of Physics, Chandigarh (India); Biswas, D.C. [Bhabha Atomic Research Center, Nuclear Physics Division, Trombay, Mumbai (India)

    2017-04-15

    Nuclear level lifetimes of high spin states in yrast and non-yrast bands of {sup 188}Pt nucleus have been measured using recoil distance plunger setup present at IUAC, Delhi. In the experiment nuclear states of interest were populated via {sup 174}Yb({sup 18}O,4n){sup 188}Pt reaction at a beam energy of 79MeV provided by 15 UD Pelletron accelerator. The extracted B(E2 ↓) values show an initial rise up to 4{sup +} state and then a nearly constant behavior with spin along yrast band, indicating change of nuclear structure in {sup 188}Pt at low spins. The good agreement between experimental and TPSM model B(E2 ↓) values up to 4{sup +} state suggests an increase in axial deformation of the nucleus. The average absolute β{sub 2} = 0.20 (3) obtained from measured B(E2 ↓) values matches well the values predicted by CHFB and IBM calculations for oblate (β{sub 2} ∝ -0.19) and prolate (β{sub 2} ∝ 0.22) shapes. As the lifetime measurements do not yield the sign of β{sub 2}, no definite conclusion can be drawn on the prolate or oblate collectivity of {sup 188}Pt on the basis of present measurements. (orig.)

  17. Cold and Slow Molecular Beam

    CERN Document Server

    Lu, Hsin-I; Wright, Matthew J; Patterson, Dave; Doyle, John M

    2011-01-01

    Employing a two-stage cryogenic buffer gas cell, we produce a cold, hydrodynamically extracted beam of calcium monohydride molecules with a near effusive velocity distribution. Beam dynamics, thermalization and slowing are studied using laser spectroscopy. The key to this hybrid, effusive-like beam source is a "slowing cell" placed immediately after a hydrodynamic, cryogenic source [Patterson et al., J. Chem. Phys., 2007, 126, 154307]. The resulting CaH beams are created in two regimes. One modestly boosted beam has a forward velocity of vf = 65 m/s, a narrow velocity spread, and a flux of 10^9 molecules per pulse. The other has the slowest forward velocity of vf = 40 m/s, a longitudinal temperature of 3.6 K, and a flux of 5x10^8 molecules per pulse.

  18. Precision Muonium Spectroscopy

    CERN Document Server

    Jungmann, Klaus P

    2016-01-01

    The muonium atom is the purely leptonic bound state of a positive muon and an electron. It has a lifetime of 2.2 $\\mu$s. The absence of any known internal structure provides for precision experiments to test fundamental physics theories and to determine accurate values of fundamental constants. In particular groun dstate hyperfine structure transitions can be measured by microwave spectroscopy to deliver the muon magnetic moment. The frequency of the 1s-2s transition in the hydrogen-like atom can be determined with laser spectroscopy to obtain the muon mass. With such measurements fundamental physical interactions, in particular Quantum Electrodynamics, can also be tested at highest precision. The results are important input parameters for experiments on the muon magnetic anomaly. The simplicity of the atom enables further precise experiments, such as a search for muonium-antimuonium conversion for testing charged lepton number conservation and searches for possible antigravity of muons and dark matter.

  19. Precision Muonium Spectroscopy

    Science.gov (United States)

    Jungmann, Klaus P.

    2016-09-01

    The muonium atom is the purely leptonic bound state of a positive muon and an electron. It has a lifetime of 2.2 µs. The absence of any known internal structure provides for precision experiments to test fundamental physics theories and to determine accurate values of fundamental constants. In particular ground state hyperfine structure transitions can be measured by microwave spectroscopy to deliver the muon magnetic moment. The frequency of the 1s-2s transition in the hydrogen-like atom can be determined with laser spectroscopy to obtain the muon mass. With such measurements fundamental physical interactions, in particular quantum electrodynamics, can also be tested at highest precision. The results are important input parameters for experiments on the muon magnetic anomaly. The simplicity of the atom enables further precise experiments, such as a search for muonium-antimuonium conversion for testing charged lepton number conservation and searches for possible antigravity of muons and dark matter.

  20. Breast cancer margin delineation with fluorescence lifetime imaging (Conference Presentation)

    Science.gov (United States)

    Phipps, Jennifer E.; Gorpas, Dimitris; Darrow, Morgan; Unger, Jakob; Bold, Richard; Marcu, Laura

    2017-02-01

    The current standard of care for early stages of breast cancer is breast-conserving surgery (BCS). BCS involves a lumpectomy procedure, during which the tumor is removed with a rim of normal tissue-if cancer cells found in that rim of tissue, it is called a positive margin and means part of the tumor remains in the breast. Currently there is no method to determine if cancer cells exist at the margins of lumpectomy specimens aside from time-intensive histology methods that result in reoperations in up to 38% of cases. We used fluorescence lifetime imaging (FLIm) to measure time-resolved autofluorescence from N=13 ex vivo human breast cancer specimens (N=10 patients undergoing lumpectomy or mastectomy) and compared our results to histology. Tumor (both invasive and ductal carcinoma in situ), fibrous tissue, fat and fat necrosis have unique fluorescence signatures. For instance, between 500-580 nm, fluorescence lifetime of tumor was shortest (4.7 +/- 0.4 ns) compared to fibrous tissue (5.5 +/- 0.7 ns) and fat (7.0 +/- 0.1 ns), P<0.05 (ANOVA). These differences are due to the biochemical properties of lipid, nicotineamide adenine dinucleotide (NADH) and collagen fibers in the fat, tumor and fibrous tissue, respectively. Additionally, the FLIm data is augmented to video of the breast tissue with image processing algorithms that track a blue (450 nm) aiming beam used in parallel with the 355 nm excitation beam. This allows for accurate histologic co-registration and in the future will allow for three-dimensional lumpectomy surfaces to be imaged for cancer margin delineation.

  1. Lifetimes of states in 19Ne above the 15 O + alpha breakup threshold

    CERN Document Server

    Mythili, S; Alexander, T K; Ball, G C; Chicoine, M; Chakrawarthy, R S; Churchman, R; Forster, J S; Gujrathi, S; Hackman, G; Howell, D; Kanungo, R; Leslie, J R; Padilla, E; Pearson, C J; Ruiz, C; Ruprecht, G; Schumaker, M A; Tanihata, I; Vockenhuber, C; Walden, P; Yen, S

    2007-01-01

    The 15O(alpha,gamma)19Ne reaction plays a role in the ignition of Type I x-ray bursts on accreting neutron stars. The lifetimes of states in 19Ne above the 15O + alpha threshold of 3.53 MeV are important inputs to calculations of the astrophysical reaction rate. These levels in 19Ne were populated in the 3He(20Ne,alpha)19Ne reaction at a 20Ne beam energy of 34 MeV. The lifetimes of six states above the threshold were measured with the Doppler shift attenuation method (DSAM). The present measurements agree with previous determinations of the lifetimes of these states and in some cases are considerably more precise.

  2. Fabrication of {sup 94}Zr thin target for recoil distance doppler shift method of lifetime measurement

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, C.K.; Rohilla, Aman [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Abhilash, S.R.; Kabiraj, D.; Singh, R.P. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Mehta, D. [Department of Physics, Panjab University, Chandigarh 160014 (India); Chamoli, S.K., E-mail: skchamoli@physics.du.ac.in [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

    2014-11-11

    A thin isotopic {sup 94}Zr target of thickness 520μg/cm{sup 2} has been prepared for recoil distance Doppler shift method (RDM) lifetime measurement by using an electron beam deposition method on tantalum backing of 3.5 mg/cm{sup 2} thickness at Inter University Accelerator Center (IUAC), New Delhi. To meet the special requirement of smoothness of surface for RDM lifetime measurement and also to protect the outer layer of {sup 94}Zr from peeling off, a very thin layer of gold has been evaporated on a {sup 94}Zr target on a specially designed substrate holder. In all, 143 mg of 99.6% enriched {sup 94}Zr target material was utilized for the fabrication of {sup 94}Zr targets. The target has been successfully used in a recent RDM lifetime measurement experiment at IUAC.

  3. Measuring lifetimes of long-lived charged massive particles stopped in LHC detectors.

    Science.gov (United States)

    Asai, Shoji; Hamaguchi, Koichi; Shirai, Satoshi

    2009-10-02

    Long-lived charged massive particles (CHAMPs) appear in various particle physics models beyond the standard model. In this Letter, we discuss the prospects for studying the stopping and decaying events of such long-lived CHAMPs at the LHC detectors, and show that the lifetime measurement (and the study of decay products) is possible with the LHC detectors for a wide range of the lifetime O(0.1)-O(10(10)) sec, by using periods of no pp collision. Even a short lifetime of order 1 sec can be measured by (i) identifying the stopping event with the on-line event filter, (ii) immediately making a beam-dump signal which stops the pp collision of the LHC, and at the same time (iii) changing the trigger menu to optimize it for the detection of a CHAMP decay in the calorimeter. Other possibilities are also discussed.

  4. A new method for measuring the neutron lifetime using an in situ neutron detector

    CERN Document Server

    Morris, C L; Broussard, L J; Callahan, N B; Clayton, S M; Cude-Woods, C; Currie, S A; Ding, X; Fox, W; Hickerson, K P; Holley, A T; Komives, A; Liu, C -Y; Makela, M; Pattie, R W; Ramsey, J; Salvat, D J; Saunders, A; Seestrom, S J; Sharapov, E I; Sjue, S K; Tang, Z; Vanderwerp, J; Vogelaar, B; Walstrom, P L; Wang, Z; Wei, Wanchun; Wexler, J W; Womack, T L; Young, A R; Zeck, B A

    2016-01-01

    The neutron lifetime is important in understanding the production of light nuclei in the first minutes after the big bang and it provides basic information on the charged weak current of the standard model of particle physics. Two different methods have been used to measure the neutron lifetime: disappearance measurements using bottled ultracold neutrons and decay rate measurements using neutron beams. The best measurements using these two techniques give results that differ by nearly 4 standard deviations. In this paper we describe a new method for measuring surviving neutrons in neutron lifetime measurements using bottled ultracold neutrons that provides better characterization of systematic uncertainties and enables higher precision than previous measurement techniques. We present results obtained using our method.

  5. Lifetime measurement of 2+1 state in 74Zn by differential plunger method

    CERN Document Server

    Niikura, M; Azaiez, F; Franchoo, S; Matea, I; Stefan, I; Verney, D; Assie, M; Bednarczyk, P; Borcea, C; Burger, A; Burgunder, G; Buta, A; Càceres, L; Clément, 2 E; Coquard, L; de Angelis, G; de France, G; Santos, F de Oliveira; Dewald, A; Dijon, A; Dombradi, Z; Fiori, E; Fransen, C; Friessner, G; Gaudefroy, L; Georgiev, G; Grévy, S; Hackstein, M; Harakeh, M N; Ibrahim, F; Kamalou, O; Kmiecik, M; Lozeva, R; Maj, A; Mihai, C; Möller, O; Myalski, S; Negoita, F; Pantelica, D; Perrot, L; Pissulla, Th; Rotaru, F; Rother, W; Scarpaci, J A; Stodel, C; Thomas, J C; Ujic, P

    2011-01-01

    We report here the first direct lifetime measurement of the 2+1 state in 74Zn. The neutron-rich 74Zn beam was produced by in-flight fragmentation of 76Ge at the Grand Accelerateur National d'Ions Lourds and separated with the LISE spectrometer. The 2+1 state was excited by inelastic scattering on a CD2 target and the lifetime was measured by the recoil distance Doppler-shift method with the K\\"oln plunger device combined with the EXOGAM detectors. The lifetime of the 2+1 state in 74Zn was determined to be 27.0(24) ps, which corresponds to a reduced transition probability B(E2; 2+1 \\to 0+) = 370(33) e2fm4.

  6. Estimation of the impurity levels in polyimide foils and the life-time of the foils irradiated by charged projectiles

    Science.gov (United States)

    Jaskóła, M.; Korman, A.; Stolarz, A.

    2008-06-01

    The life-time of thin polyimide foils (prepared by in-situ polymerisation) in beams of 2.0 MeV helium ions and 1.5 MeV protons has been studied, irradiating foils with beams of different intensities. The impurity levels of the foils measured by PIXE and RBS were found to be in order of ng/cm 2.

  7. Hyperon Beam Experiment

    CERN Multimedia

    2002-01-01

    The experiment WA89 uses the upgraded Omega facility together with a hyperon beam installed at the end of the H1 beamline. The beam can deliver 2~10$ ^{5} \\% Sigma ^- $ per machine burst at 330 GeV/c with a background of 5 10$ ^{5} \\% \\pi ^- $. \\\\ \\\\ The goals of the experiment are: observation of charmed particles, mainly the charmed-strange baryons and measurements of their production in the kinematical range x$ _{F} $~$>$~0.2, and their decay properties, a search for exotic states such as U(3100) observed in the previous CERN hyperon beam experiment WA62, measurements of hyperon polarization and production properties. \\\\ \\\\ A vertex detector consisting of 24 silicon microstrip planes with 25~$\\mu$m pitch and 6~planes with 50~$\\mu$m pitch provides track measurements of sufficient accuracy to identify the decays of short living charmed particles and measure their lifetimes. A RICH detector provides good $\\pi$/K separation for momenta up to 100~GeV/c and $\\pi$/p separation up to 150~GeV/c. Photons are detecte...

  8. Beam loading

    CERN Document Server

    Gamp, Alexander

    2013-01-01

    We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  9. Parity lifetime of bound states in a proximitized semiconductor nanowire

    Science.gov (United States)

    Higginbotham, A. P.; Albrecht, S. M.; Kiršanskas, G.; Chang, W.; Kuemmeth, F.; Krogstrup, P.; Jespersen, T. S.; Nygård, J.; Flensberg, K.; Marcus, C. M.

    2015-12-01

    Quasiparticle excitations can compromise the performance of superconducting devices, causing high-frequency dissipation, decoherence in Josephson qubits, and braiding errors in proposed Majorana-based topological quantum computers. Quasiparticle dynamics have been studied in detail in metallic superconductors but remain relatively unexplored in semiconductor-superconductor structures, which are now being intensely pursued in the context of topological superconductivity. To this end, we use a system comprising a gate-confined semiconductor nanowire with an epitaxially grown superconductor layer, yielding an isolated, proximitized nanowire segment. We identify bound states in the semiconductor by means of bias spectroscopy, determine the characteristic temperatures and magnetic fields for quasiparticle excitations, and extract a parity lifetime (poisoning time) of the bound state in the semiconductor exceeding 10 ms.

  10. Gigantic Surface Lifetime of an Intrinsic Topological Insulator

    Science.gov (United States)

    Neupane, Madhab; Xu, Su-Yang; Ishida, Yukiaki; Jia, Shuang; Fregoso, Benjamin M.; Liu, Chang; Belopolski, Ilya; Bian, Guang; Alidoust, Nasser; Durakiewicz, Tomasz; Galitski, Victor; Shin, Shik; Cava, Robert J.; Hasan, M. Zahid

    2015-09-01

    The interaction between light and novel two-dimensional electronic states holds promise to realize new fundamental physics and optical devices. Here, we use pump-probe photoemission spectroscopy to study the optically excited Dirac surface states in the bulk-insulating topological insulator Bi2Te2Se and reveal optical properties that are in sharp contrast to those of bulk-metallic topological insulators. We observe a gigantic optical lifetime exceeding 4 μ s (1 μ s =10-6 s ) for the surface states in Bi2Te2Se , whereas the lifetime in most topological insulators, such as Bi2Se3 , has been limited to a few picoseconds (1 ps =10-12 s ). Moreover, we discover a surface photovoltage, a shift of the chemical potential of the Dirac surface states, as large as 100 mV. Our results demonstrate a rare platform to study charge excitation and relaxation in energy and momentum space in a two-dimensional system.

  11. Origin of tryptophan fluorescence lifetimes. Part 2: fluorescence lifetimes origin of tryptophan in proteins.

    Science.gov (United States)

    Albani, J R

    2014-01-01

    Fluorescence intensity decays of L-tryptophan in proteins dissolved in pH 7 buffer, in ethanol and in 6 M guanidine pH 7.8 and in lyophilized proteins were measured. In all protein conditions, three lifetimes were obtained along the emission spectrum (310-410 nm). The two shortest lifetimes are in the same range of those obtained for L-Trp in water or in ethanol. Thus, these two lifetimes originate from specific two sub-structures existing in the excited state and are inherent to the tryptophan structure independently of the surrounding environment (amino acids residues, solvent, etc.) In proteins, the third lifetime originates from the interactions that are occurring between tryptophan residues and neighboring amino acids. Populations of these lifetimes are independent of the excitation wavelength and thus originate from pre-defined sub structures existing in the excited state and put into evidence after tryptophan excitation. Fluorescence decay studies of different tripeptides having a tryptophan residue in second position show that the best analysis is obtained with two fluorescence lifetimes. Consequently, this result seems to exclude the possibility that peptide bond induces the third fluorescence lifetimes. Indole dissolved in water and/or in ethanol emits with two fluorescence lifetimes that are completely different from those observed for L-Trp. Absence of the third lifetime in ethanol demonstrates that indole behaves differently when compared to tryptophan. Thus, it seems not adequate to attribute fluorescence lifetime or fluorescence properties of tryptophan to indole ring and to compare tryptophan fluorescence properties in proteins to molecules having close structures such as NATA which fluoresces with one lifetime.

  12. Miniaturized Sources and Traps for Spectroscopy of Multicharged Ions

    Science.gov (United States)

    Tan, Joseph; Guise, Nicholas

    2013-05-01

    Penning traps made extremely compact (earth (NdFeB) magnets have been used recently to isolate highly charged ions (HCI) for spectroscopy. For example, radiative lifetimes of metastable states are measured by observing the visible fluorescence emitted by isolated Ar XIV (441 nm, 2p 2P3/2 --> 2p 2P1/2) and Kr XVIII (637 nm, 3d 2D3/2 --> 3d 2D1/2) . These measurements use HCIs extracted from an electron beam ion trap (EBIT) at NIST. For planned experiments, a new apparatus is being developed which will incorporate a ``mini-EBIT'' source using similar permanent-magnet structures. It combines a mini-EBIT and a compact Penning trap to facilitate production of multicharged ions including bare nuclei with nuclear charge in the range Z =1 to Z =10, in a cryogen-free setup with multiple ports for laser and atomic beam access to the isolated HCI. One goal is to produce one-electron ions in Rydberg states with transitions accessible to an optical frequency comb. Such engineered atomic systems are sought to enable tests of theory that could illuminate the proton radius puzzle. J.N. Tan, S.M. Brewer, and N.D. Guise, Rev. Sci. Instrum. 83, 023103 (2012).

  13. Measurements of excitation spectra and level lifetimes for highly charged neon ions

    Institute of Scientific and Technical Information of China (English)

    王友德; 马新文; 杨治虎; 杜一飞; 刘惠萍; 赵孟春; 郭天瑞; 王春芳

    1997-01-01

    Beam foil experiments were carried out for 47 MeV Ne ions passing through C (39 μg/cm2) and Al (3 4mg/cm2) foils. Highly charged H-, He-, Li-, and Be-like ions were obtained after the foils. The excitation spectra and level lifetimes for these ions were measured, and transition configurations for most measured lines were identified

  14. Lifetime measurements for some n=2 levels in Be-like S ⅩⅢ

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Highly ionized Spectra from sulfur obtained at an energy of 80 MeV have been studied in the 19.0~53.0 nm wavelength range. Radiative lifetimes for some n=2 level in Be+-like S ⅩⅢwere measured using he beam-foil time of flight method. The results, using an arbitrarily normalized decay curves analysis, are compared with theoretical predictions and earlier measurement.

  15. Lifetimes and Oscillator Strengths for Ultraviolet Transitions in Singly-Ionized Tin

    CERN Document Server

    Heidarian, N; Federman, S R; Ellis, D G; Cheng, S; Curtis, L J

    2016-01-01

    Lifetime measurements using beam foil techniques for the $5s5p^{2}$ $^{2}D_{3/2,5/2}$ levels in Sn II are presented. The resulting oscillator strengths for transitions at 1699.4, 1831.8 and 1811.2 \\AA{} are reported. We also studied these levels with multi-configuration Dirac Hartree-Fock (MCDHF) calculations using a development version of the GRASP2K package. Our experimental and theoretical results are compared with other available studies.

  16. In-beam gamma-ray spectroscopy of neutron-rich nuclei using fragmentation of radioactive beams and half-lives measurements of excited levels in nuclei closed to {sup 68}Ni; Spectroscopie {gamma} en ligne de noyaux legers riches en neutrons produits par fragmentation de faisceau radioactif et mesures de temps de vie des niveaux excites dans des noyaux proches de {sup 68}Ni

    Energy Technology Data Exchange (ETDEWEB)

    Stanoiu, M.A

    2003-01-01

    This thesis deals with studies of nuclei far from the valley of stability produced at GANIL by projectile fragmentation at intermediate energies. It consists of two parts. The first one is dedicated to the study of very light exotic nuclei around N=14. This is the first time that online {gamma}-ray spectroscopy combined with the projectile fragmentation was used with radioactive incident beams at GANIL. The advantages and the limitations of this method were established. 40 different nuclei have been produced and studied at the same time. A strong dependence of the population of excited states on the type of projectile was observed. New information was obtained on the structure of the isotopes B{sup 14,15}, C{sup 17,18,19,20}, N{sup 18,19,20,21,22}, O{sup 22,23,24}, F{sup 24,25,26} and Ne{sup 29}. The level schemes obtained from this study have been compared with shell-model predictions. In particular, the energy of 1588(20) keV found for the first 2{sup +} excited state in C{sup 20}, as well as the non-existence of a bound state in O{sup 24}, show that the proton-neutron interaction plays an important role in the structure of these nuclei. In the second part, an experiment is presented concerning the neutron-rich isomer nuclei around Ni{sup 68} produced by the LISE spectrometer. The fast-timing method was applied for the first time for the study of nuclei produced by projectile fragmentation. Subnanosecond half-lives of several levels in Ni{sup 67,69,90} and Cu{sup 71,72} were measured simultaneously and with high precision. These results have allowed us to test the shell model predictions for several E2 transitions and their associated B(E2) transition probabilities. (author)

  17. Lifetime Models for Lithium-ion Batteries used in Virtual Power Plant Applications

    DEFF Research Database (Denmark)

    Stroe, Daniel Ioan

    . Moreover, in this thesis, the use of the electrochemical impedance spectroscopy (EIS) technique was proposed as a method to estimate the pulse power capability decrease, which is caused by ageing, of the tested LFP/C battery cells. The developed lifetime models were used to analyse the degradation......The penetration of wind power into the power system has been increasing in recent years. However, despite its environmental friendliness, the wind power grid integration at a large scale faces several limitations, mainly caused by the characteristics of the wind (i.e. intermittent, variable......-ion batteries are presented in the literature. In this thesis an equivalent-electrical circuit performance-degradation modelling approach was followed to develop the lifetime models for the selected LFP/C battery cells. In order to develop the desired lifetime model, laboratory ageing tests are mandatory...

  18. Simultaneous measurement of doping concentration and carrier lifetime in silicon using terahertz time-domain transmission

    Science.gov (United States)

    Lenz, M.; Matheisen, C.; Nagel, M.; Knoch, J.

    2017-02-01

    In this work, we present a measurement approach enabling the simultaneous determination of sheet resistance and carrier lifetime in semiconductor samples. It is based on a classic Terahertz (THz) time-domain transmission spectroscopy scheme extended by quasi-steady state optical excitation. The carrier lifetime is determined by contactless THz probing of the increase in sheet conductance associated with quasi-steady-state excitation. Combining a successive etch-back of the surface with repeated THz measurements yields a depth profile of the doping concentration and the carrier lifetime, which is important for the optimization of the emitter of solar cells, for instance. The viability of our approach is demonstrated by investigating a phosphorous doped emitter of a silicon solar cell with the THz approach and comparing the results with electrochemical capacitance voltage measurements.

  19. Vibrational Infrared Lifetime of the Anesthetic nitrous oxide gas in solution

    CERN Document Server

    Chieffo, Logan; Shattuck, Jeffrey; Hong, Mi K; Ziegler, Lawrence; Erramilli, Shyamsunder

    2006-01-01

    The lifetime of the asymmetric fundamental stretching 2218 cm$^{-1}$ vibration of the anesthetic gas nitrous oxide (N$_2$O) dissolved in octanol and olive oil is reported. These solvents are model systems commonly used to assess anesthetic potency. Picosecond time-scale molecular dynamics simulations have suggested that protein dynamics or membrane dynamics play a role in the molecular mechanism of anesthetic action. Ultrafast infrared spectroscopy with 100 fs time resolution is an ideal tool to probe dynamics of anesthetic molecules on such timescales. Pump-probe studies at the peak of the vibrational band yield a lifetime of $55 \\pm 1$ ps in olive oil and $52 \\pm 1 ps$ in octanol. The similarity of lifetimes suggests that energy relaxation of the anesthetic is determined primarily by the hydrophobic nature of the environment, consistent with models of anesthetic action. The results show that nitrous oxide is a good model system for probing anesthetic-solvent interactions using nonlinear infrared spectroscop...

  20. Chevron beam dump for ITER edge Thomson scattering system.

    Science.gov (United States)

    Yatsuka, E; Hatae, T; Vayakis, G; Bassan, M; Itami, K

    2013-10-01

    This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due to nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated.

  1. Chevron beam dump for ITER edge Thomson scattering system

    Science.gov (United States)

    Yatsuka, E.; Hatae, T.; Vayakis, G.; Bassan, M.; Itami, K.

    2013-10-01

    This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due to nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated.

  2. Sensitive spectroscopy of an ytterbium atomic beam

    CERN Document Server

    Guttridge, A; Kemp, S L; Boddy, D; Freytag, R; Tarbutt, M R; Hinds, E A; Cornish, S L

    2015-01-01

    Experimental studies of ultracold ytterbium atoms generally involve the frequency stabilisation (locking) of lasers to two transitions at 399 and 556 nm in order to implement laser cooling. Here we present a simple and robust apparatus for generation of suitable, narrow fluorescence signals with a high signal to noise ratio at both wavelengths. The design utilises easily acquired vacuum parts, optics and electronics and requires very little laser power. We demonstrate the stability and precision of the frequency stabilisation at 556 nm by presenting sensitive measurements of the gravitational sag of an ytterbium MOT as a function of laser power.

  3. Detailed report of the MuLan measurement of the positive muon lifetime and determination of the Fermi constant

    NARCIS (Netherlands)

    Tishchenko, V.; Battu, S.; Carey, R. M.; Chitwood, D. B.; Crnkovic, J.; Debevec, P. T.; Dhamija, S.; Earle, W.; Gafarov, A.; Giovanetti, K.; Gorringe, T. P.; Gray, F. E.; Hartwig, Z.; Hertzog, D. W.; Johnson, B.; Kammel, P.; Kiburg, B.; Kizilgul, S.; Kunkle, J.; Lauss, B.; Logashenko, I.; Lynch, K. R.; McNabb, R.; Miller, J. P.; Mulhauser, F.; Onderwater, C. J. G.; Peng, Q.; Phillips, J.; Rath, S.; Roberts, B.L.; Webber, D. M.; Winter, P.; Wolfe, B.

    2013-01-01

    We present a detailed report of the method, setup, analysis, and results of a precision measurement of the positive muon lifetime. The experiment was conducted at the Paul Scherrer Institute using a time-structured, nearly 100% polarized surface muon beam and a segmented, fast-timing plastic scintil

  4. Lifetimes of Rydberg states of Eu atoms

    Science.gov (United States)

    Jing, Hua; Ye, Shi-Wei; Dai, Chang-Jian

    2015-01-01

    The radiative lifetimes of the Eu 4f76snp (8PJ or 10PJ) Rydberg states with J = 5/2 and 11/2 are investigated with a combination of multi-step laser excitation and pulsed electric field ionization, from which their dependence on the effective principal quantum number is observed. The lifetimes of 21 states are reported along with an evaluation of their experimental uncertainty. The influence of blackbody radiation, due to the oven temperature, on the lifetime of the higher-n states is detected. The non-hydrogen behavior of the investigated states is also observed. Project supported by the National Natural Science Foundation of China (Grant No. 11174218).

  5. Improved lifetime of microchannel-plate PMTs

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, A., E-mail: lehmann@physik.uni-erlangen.de [Physikalisches Institut IV, Friedrich Alexander-University of Erlangen-Nuremberg, Erlangen (Germany); Britting, A.; Eyrich, W.; Uhlig, F. [Physikalisches Institut IV, Friedrich Alexander-University of Erlangen-Nuremberg, Erlangen (Germany); Dzhygadlo, R.; Gerhardt, A.; Götzen, K.; Höhler, R.; Kalicy, G.; Kumawat, H.; Lehmann, D.; Lewandowski, B.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Zühlsdorf, M. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt (Germany); and others

    2014-12-01

    The charged particle identification at the PANDA experiment will be mainly performed with DIRC detectors. Because of their advantageous properties the preferred photon sensors are MCP-PMTs. However, until recently these devices showed serious aging problems which resulted in a diminishing quantum efficiency (QE) of the photo cathode. By applying innovative countermeasures against the aging causes, the manufacturers recently succeeded in drastically improving the lifetime of MCP-PMTs. Especially the application of an ALD coating technique to seal the material of the micro-channels proves very powerful and results in a lifetime of ≈6C/cm{sup 2} integrated anode charge without a substantial QE degradation for the latest PHOTONIS XP85112. This paper will present a comparative measurement of the lifetime of several older and recent MCP-PMTs demonstrating this progress.

  6. Lifetime of B hadrons from CDF

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Ting; CDF Collaboration

    1996-08-01

    A review of the lifetimes of {ital B} hadrons measured by the CDF collaboration at Fermilab is presented. The data corresponds to 110 pb{sup -1} of {ital p}{ital {anti p}} collisions at {radical}s = 1.8 TeV. The inclusive {ital B} hadron lifetime is measured using a high statistics sample of {ital B} {r_arrow} {ital J}/{Psi}{Chi} decays. Species specific lifetimes of the {ital B}{sup +}, {ital B}{sup 0}, {ital B}{sup 0}{sub s}, and {Lambda}{sup 0}{sub b} are determined using both fully reconstructed decays and partially reconstructed decays consisting of a lepton associated with a charm hadron.

  7. Improved lifetime of microchannel-plate PMTs

    Science.gov (United States)

    Lehmann, A.; Britting, A.; Eyrich, W.; Uhlig, F.; Dzhygadlo, R.; Gerhardt, A.; Götzen, K.; Höhler, R.; Kalicy, G.; Kumawat, H.; Lehmann, D.; Lewandowski, B.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Zühlsdorf, M.; Dodokhov, V. Kh.; Düren, M.; Föhl, K.; Hayrapetyan, A.; Kröck, B.; Merle, O.; Rieke, J.; Cowie, E.; Keri, T.; Montgomery, R.; Rosner, G.; Achenbach, P.; Cardinali, M.; Hoek, M.; Lauth, W.; Sfienti, C.; Thiel, M.; Bühler, P.; Gruber, L.; Marton, J.; Suzuki, K.

    2014-12-01

    The charged particle identification at the PANDA experiment will be mainly performed with DIRC detectors. Because of their advantageous properties the preferred photon sensors are MCP-PMTs. However, until recently these devices showed serious aging problems which resulted in a diminishing quantum efficiency (QE) of the photo cathode. By applying innovative countermeasures against the aging causes, the manufacturers recently succeeded in drastically improving the lifetime of MCP-PMTs. Especially the application of an ALD coating technique to seal the material of the micro-channels proves very powerful and results in a lifetime of ≈ 6 C /cm2 integrated anode charge without a substantial QE degradation for the latest PHOTONIS XP85112. This paper will present a comparative measurement of the lifetime of several older and recent MCP-PMTs demonstrating this progress.

  8. Measurement of the $\\tau$ lepton lifetime

    CERN Document Server

    Buskulic, Damir; De Bonis, I; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Odier, P; Pietrzyk, B; Ariztizabal, F; Chmeissani, M; Crespo, J M; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Gaitan, V; Garrido, L; Martínez, M; Orteu, S; Pacheco, A; Padilla, C; Palla, Fabrizio; Pascual, A; Perlas, J A; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Farilla, A; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Natali, S; Nuzzo, S; Ranieri, A; Raso, G; Romano, F; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Engelhardt, A; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Jacobsen, R; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Markou, C; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Oest, T; Palazzi, P; Pater, J R; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wiedenmann, W; Wildish, T; Witzeling, W; Wotschack, J; Ajaltouni, Ziad J; Bardadin-Otwinowska, Maria; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rossignol, J M; Saadi, F; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Kyriakis, A; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Passalacqua, L; Rougé, A; Rumpf, M; Tanaka, R; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Delfino, M C; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Pepé-Altarelli, M; Dorris, S J; Halley, A W; ten Have, I; Knowles, I G; Lynch, J G; Morton, W T; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Smith, M G; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Braun, O; Geweniger, C; Graefe, G; Hanke, P; Hepp, V; Kluge, E E; Putzer, A; Rensch, B; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Colling, D J; Dornan, Peter J; Konstantinidis, N P; Moneta, L; Moutoussi, A; Nash, J; San Martin, G; Sedgbeer, J K; Stacey, A M; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Bowdery, C K; Brodbeck, T J; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Whelan, E P; Williams, M I; Galla, A; Greene, A M; Kleinknecht, K; Quast, G; Raab, J; Renk, B; Sander, H G; Wanke, R; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Thulasidas, M; Nicod, D; Payre, P; Rousseau, D; Talby, M; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Brown, D; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wolf, G; Alemany, R; Boucrot, J; Callot, O; Cordier, A; Courault, F; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Musolino, G; Nikolic, I A; Park, H J; Park, I C; Schune, M H; Simion, S; Veillet, J J; Videau, I; Abbaneo, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Fidecaro, F; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Triggiani, G; Vannini, C; Verdini, P G; Walsh, J; Betteridge, A P; Blair, G A; Bryant, L M; Cerutti, F; Gao, Y; Green, M G; Johnson, D L; Medcalf, T; Mir, L M; Perrodo, P; Strong, J A; Bertin, V; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Edwards, M; Maley, P; Norton, P R; Thompson, J C; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Beddall, A; Booth, C N; Boswell, R; Cartwright, S L; Combley, F; Dawson, I; Köksal, A; Letho, M; Newton, W M; Rankin, C; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Feigl, E; Grupen, Claus; Lutters, G; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Ragusa, F; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Bellantoni, L; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Harton, J L; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Schmitt, M; Scott, I J; Sharma, V; Turk, J; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

    1996-01-01

    The mean lifetime of the \\tau lepton is measured in a sample of 25700 \\tau pairs collected in 1992 with the ALEPH detector at LEP. A new analysis of the 1-1 topology events is introduced. In this analysis, the dependence of the impact parameter sum distribution on the daughter track momenta is taken into account, yielding improved precision compared to other impact parameter sum methods. Three other analyses of the one- and three-prong \\tau decays are updated with increased statistics. The measured lifetime is 293.5 \\pm 3.1 \\pm 1.7 \\fs. Including previous (1989--1991) ALEPH measurements, the combined \\tau lifetime is 293.7 \\pm 2.7 \\pm 1.6 \\fs.

  9. The neutron lifetime experiment PENeLOPE

    Energy Technology Data Exchange (ETDEWEB)

    Schreyer, Wolfgang [Technische Universitaet Muenchen (Germany); Collaboration: PENeLOPE-Collaboration

    2015-07-01

    The neutron lifetime τ{sub n}=880.3±1.1 s is an important parameter in the Standard Model of particle physics and in Big Bang cosmology. Several systematic corrections of previously published results reduced the PDG world average by several σ in the last years and call for a new experiment with complementary systematics. The experiment PENeLOPE, currently under construction at the Physik-Department of Technische Universitaet Muenchen, aims to determine the neutron lifetime with a precision of 0.1 s. It will trap ultra-cold neutrons in a magneto-gravitational trap using a large superconducting magnet and will measure their lifetime by both neutron counting and online proton detection. This presentation gives an overview over the latest developments of the experiment.

  10. Precision determination of the lifetime of the neutral pion

    CERN Multimedia

    2002-01-01

    The experiment aims at a determination of the lifetime of the neutral pion with an accuracy of 1\\%, as against at present 5\\% for the best measurement by the indirect, Primakoff method, and 18\\% by a direct measurement. \\\\\\\\2 gold foils with different separations are traversed by the extracted proton beam to the High Intensity Area. Positive particles of 160 GeV/c momentum from this target are transported by the H6 beam to the North Area. The electron component is separated from heavier particles by synchrotron losses in the bending magnets, and is further identified by a lead glass Cerenkov counter, in coincidence with scintillation counters (Fig. 1).\\\\\\\\ The electron flux from the double foil target depends on the distance between the foils, since for small separations the neutral pions will have to decay before electrons can be materialised by the decay $\\gamma$ rays.\\\\\\\\ The average momentum of neutral pions from a 400 GeV pN reaction, giving a 160 GeV/c electron, is about 250 GeV/c, and the corresponding...

  11. Tremendously increased lifetime of MCP-PMTs

    Science.gov (United States)

    Lehmann, A.; Britting, A.; Eyrich, W.; Pfaffinger, M.; Uhlig, F.; Belias, A.; Dzhygadlo, R.; Gerhardt, A.; Götzen, K.; Kalicy, G.; Krebs, M.; Lehmann, D.; Nerling, F.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Zühlsdorf, M.; Düren, M.; Etzelmüller, E.; Föhl, K.; Hayrapetyan, A.; Kröck, B.; Merle, O.; Rieke, J.; Schmidt, M.; Cowie, E.; Keri, T.; Achenbach, P.; Cardinali, M.; Hoek, M.; Lauth, W.; Schlimme, S.; Sfienti, C.; Thiel, M.

    2017-02-01

    Microchannel plate (MCP) PMTs are very attractive photon sensors for low light level applications in strong magnetic fields. However, until recently the main drawback of MCP-PMTs was their aging behavior which manifests itself in a limited lifetime due to a rapidly decreasing quantum efficiency (QE) of the photo cathode (PC) as the integrated anode charge (IAC) increases. In the latest models of PHOTONIS, Hamamatsu, and BINP novel techniques are applied to avoid these aging effects which are supposed to be mainly caused by feedback ion impinging on the PC and damaging it. For more than four years we are running a long-term aging test with new lifetime-enhanced MCP-PMT models by simultaneously illuminating various PMTs with roughly the same photon rate. This allows a fair comparison of the lifetime of all investigated MCP-PMTs and will give some insight into the best techniques to be applied for a lifetime enhancement. In this paper the results of comprehensive aging tests will be discussed. Gain, dark count rate and QE were investigated for their dependence on the IAC. The QE was measured spectrally resolved and as a function of the position across the PC to identify regions where the damage develops first. For the best performing tubes the lifetime improvement compared to former MCP-PMTs is a factor of ∼ 50 based on an IAC of meanwhile > 10 C /cm2. This breakthrough in the lifetime of MCP-PMTs was achieved by coating the MCP pores with an atomic layer deposition (ALD) technique.

  12. Cubosomes for in vivo fluorescence lifetime imaging

    Science.gov (United States)

    Biffi, Stefania; Andolfi, Laura; Caltagirone, Claudia; Garrovo, Chiara; Falchi, Angela M.; Lippolis, Vito; Lorenzon, Andrea; Macor, Paolo; Meli, Valeria; Monduzzi, Maura; Obiols-Rabasa, Marc; Petrizza, Luca; Prodi, Luca; Rosa, Antonella; Schmidt, Judith; Talmon, Yeshayahu; Murgia, Sergio

    2017-02-01

    Herein we provided the first proof of principle for in vivo fluorescence optical imaging application using monoolein-based cubosomes in a healthy mouse animal model. This formulation, administered at a non-cytotoxic concentration, was capable of providing both exogenous contrast for NIR fluorescence imaging with very high efficiency and chemospecific information upon lifetime analysis. Time-resolved measurements of fluorescence after the intravenous injection of cubosomes revealed that the dye rapidly accumulated mainly in the liver, while lifetimes profiles obtained in vivo allowed for discriminating between free dye or dye embedded within the cubosome nanostructure after injection.

  13. B lifetimes and mixing at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Bedeschi, Franco; /INFN, Pisa

    2005-05-01

    The authors present recent results on b-hadron lifetimes and mixing obtained from the analysis of the data collected at the Tevatron Collider by the CDF and D0 Collaborations in the period 2002-2004. Many lifetime measurements have been updated since the Summer 2004 conferences, sometimes improving significantly the accuracy. Likewise the measurement of the B{sub d} oscillation frequency has been updated. New limits on the B{sub s} oscillation frequency have been determined using for the first time Run II data.

  14. A compact positron annihilation lifetime spectrometer

    Institute of Scientific and Technical Information of China (English)

    LI Dao-Wu; LIU Jun-Hui; ZHANG Zhi-Ming; WANG Bao-Yi; ZHANG Tian-Bao; WEI Long

    2011-01-01

    Using LYSO scintillator coupled on HAMAMATSU R9800(a fast photomultiplier)to form the small size γ-ray detectors,a compact lifetime spectrometer has been built for the positron annihilation experiments.The system time resolution FWHM=193 ps and the coincidence counting rate -8 cps/μCi were achieved.A lifetime value of 219±1 ps of positron annihilation in well annealed Si was tested,which is in agreement with the typical values published in the previous lectures.

  15. Prompt Neutron Lifetime for the NBSR Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, A.L.; Diamond, D.

    2012-06-24

    In preparation for the proposed conversion of the National Institute of Standards and Technology (NIST) research reactor (NBSR) from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel, certain point kinetics parameters must be calculated. We report here values of the prompt neutron lifetime that have been calculated using three independent methods. All three sets of calculations demonstrate that the prompt neutron lifetime is shorter for the LEU fuel when compared to the HEU fuel and longer for the equilibrium end-of-cycle (EOC) condition when compared to the equilibrium startup (SU) condition for both the HEU and LEU fuels.

  16. Measurement of the Bs0 lifetime

    Science.gov (United States)

    Buskulic, D.; de Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Minard, M.-N.; Odier, P.; Pietrzyk, B.; Ariztizabal, F.; Comas, P.; Crespo, J. M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Gaitan, V.; Garrido, Ll.; Martinez, M.; Mattison, T.; Orteu, S.; Pacheco, A.; Padilla, C.; Pascual, A.; Creanza, D.; de Palma, M.; Farilla, A.; Iaselli, G.; Maggi, G.; Marinelli, N.; Natali, S.; Nuzzo, S.; Ranieri, A.; Raso, G.; Romano, F.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Chai, Y.; Hu, H.; Huang, D.; Huang, X.; Lin, J.; Wang, T.; Xie, Y.; Xu, D.; Xu, R.; Zhang, J.; Zhang, L.; Zhao, W.; Bonvicini, G.; Boudreau, J.; Casper, D.; Drevermann, H.; Forty, R. W.; Ganis, G.; Gay, C.; Girone, M.; Hagelberg, R.; Harvey, J.; Hilgart, J.; Jacobsen, R.; Jost, B.; Knobloch, J.; Lehraus, I.; Maggi, M.; Markou, C.; Mato, P.; Meinhard, H.; Minten, A.; Miquel, R.; Moser, H.-G.; Palazzi, P.; Pater, J. R.; Perlas, J. A.; Perrodo, P.; Pusztaszeri, J.-F.; Ranjard, F.; Rolandi, L.; Rothberg, J.; Ruan, T.; Saich, M.; Schlatter, D.; Schmelling, M.; Sefkow, F.; Tejessy, W.; Tomalin, I. R.; Veenhof, R.; Wachsmuth, H.; Wasserbaech, S.; Wiedenmann, W.; Wildish, T.; Witzeling, W.; Wotschack, J.; Ajaltouni, Z.; Bardadin-Otwinowska, M.; Barres, A.; Boyer, C.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Saadi, F.; Fearnley, T.; Hansen, J. B.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Johnson, S. D.; Møllerud, R.; Nilsson, B. S.; Kyriakis, A.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Badier, J.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Bourdon, P.; Fouque, G.; Passalacqua, L.; Rougé, A.; Rumpf, M.; Tanaka, R.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Veitch, E.; Focardi, E.; Moneta, L.; Parrini, G.; Corden, M.; Delfino, M.; Georgiopoulos, C.; Jaffe, D. E.; Levinthal, D.; Antonelli, A.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Cerutti, F.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Pepe-Altarelli, M.; Salomone, S.; Colrain, P.; Ten Have, I.; Knowles, I. G.; Lynch, J. G.; Maitland, W.; Morton, W. T.; Raine, C.; Reeves, P.; Scarr, J. M.; Smith, K.; Smith, M. G.; Thompson, A. S.; Thorn, S.; Turnbull, R. M.; Brandl, B.; Braun, O.; Geweniger, C.; Graefe, G.; Hanke, P.; Hepp, V.; Karger, C.; Kluge, E. E.; Maumary, Y.; Putzer, A.; Rensch, B.; Stahl, A.; Tittel, K.; Wunsch, M.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Cattaneo, M.; Colling, D. J.; Dornan, P. J.; Hassard, J. F.; Lieske, N. M.; Moutoussi, A.; Nash, J.; Patton, S.; Payne, D. G.; Phillips, M. J.; San Martin, G.; Sedgbeer, J. K.; Wright, A. G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Vogl, R.; Bowdery, C. K.; Brodbeck, T. J.; Finch, A. J.; Foster, F.; Hughes, G.; Jackson, D.; Keemer, N. R.; Nuttall, M.; Patel, A.; Sloan, T.; Snow, S. W.; Whelan, E. P.; Galla, A.; Greene, A. M.; Kleinknecht, K.; Raab, J.; Renk, B.; Sander, H.-G.; Schmidt, H.; Walther, S. M.; Wanke, R.; Wolf, B.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Calvet, D.; Carr, J.; Coyle, P.; Diaconu, C.; Drinkard, J.; Etienne, F.; Nicod, D.; Payre, P.; Ross, L.; Rousseau, D.; Schwemling, P.; Talby, M.; Adlung, S.; Assmann, R.; Bauer, C.; Blum, W.; Brown, D.; Cattaneo, P.; Dehning, B.; Dietl, H.; Dydak, F.; Frank, M.; Halley, A. W.; Jakobs, K.; Lauber, J.; Lütjens, G.; Lutz, G.; Männer, W.; Richter, R.; Schröder, J.; Schwarz, A. S.; Settles, R.; Seywerd, H.; Stierlin, U.; Stiegler, U.; Denis, R. St.; Wolf, G.; Alemany, R.; Boucrot, J.; Callot, O.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Janot, P.; Kimfn 19, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Musolino, G.; Schune, M.-H.; Veillet, J.-J.; Videau, I.; Abbaneo, D.; Bagliesi, G.; Batignani, G.; Bottigli, U.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Ciulli, V.; Dell'Orso, R.; Ferrante, I.; Fidecaro, F.; Foà, L.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Mannelli, E. B.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Valassi, A.; Vannini, C.; Venturi, A.; Verdini, P. G.; Walsh, J.; Betteridge, A. P.; Gao, Y.; Green, M. G.; Johnson, D. L.; March, P. V.; Medcalf, T.; Mir, Ll. M.; Quazi, I. S.; Strong, J. A.; Bertin, V.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Haywood, S.; Edwards, M.; Norton, P. R.; Thompson, J. C.; Bloch-Devaux, B.; Colas, P.; Duarte, H.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Marx, B.; Perez, P.; Rander, J.; Renardy, J.-F.; Rosowsky, A.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Si Mohand, D.; Vallage, B.; Johnson, R. P.; Litke, A. M.; Taylor, G.; Wear, J.; Babbage, W.; Booth, C. N.; Buttar, C.; Cartwright, S.; Combley, F.; Dawson, I.; Thompson, L. F.; Barberio, E.; Böhrer, A.; Brandt, S.; Cowan, G.; Grupen, C.; Lutters, G.; Rivera, F.; Schäfer, U.; Smolik, L.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Pitis, L.; Ragusa, F.; Bellantoni, L.; Chen, W.; Conway, J. S.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; Grahl, J.; Harton, J. L.; Hayes, O. J.; Nachtman, J. M.; Pan, Y. B.; Saadi, Y.; Schmitt, M.; Scott, I.; Sharma, V.; Shi, Z. H.; Turk, J. D.; Walsh, A. M.; Weber, F. V.; Lan Wu, Sau; Wu, X.; Zheng, M.; Zobernig, G.; Aleph Collaboration

    1994-02-01

    The lifetime of the Bs0 has been measured in a data sample of 8890000 hadronic events recorded with the ALEPH detector at LEP. After background subtraction 30.8 ± 6.9 events are attributed to the semileptonic decay of the Bs0 to a Ds- and an opposite-sign lepton. A maximum-likelihood fit to the distribution of the proper times of these events yields a Bs0 lifetime of τBs = 1.92 -0.35+0.45 ± 0.04 ps.

  17. An approach for longer lifetime MCFCs

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Masaru; Tatsumi, Masahiko; Hayano, Takuro [MCFC Research Association, Tokyo (Japan)] [and others

    1996-12-31

    For entering into commercialization of MCFC power plants in the beginning of the 21st century, we will devote to research for increasing lifetime as long as 40,000 hours with cell performance decay rate of 0.25 %/1000hrs as the target in FY 1999. This paper will discuss on our approach for longer lifetime MCFCs through electrolyte-loss management and NiO precipitation management as well as micro-structural control of electrodes and matrix plates. Cell voltage decay rate will be estimated by simulation through series of experiments on accelerated conditions.

  18. A Study on Criteria for Barrel Lifetime

    Institute of Scientific and Technical Information of China (English)

    马吉胜; 郑坚; 邓辉咏

    2012-01-01

    Several criteria for barrel lifetime were summarized and discussed. Based on large amount of test data, the ad- vantages and disadvantages of the criteria were analyzed and the requirements for the easy and practical criterion were put forward. Then, a new criterion based on the radical wear at the start points of the barrel lands was proposed. The close in- terrelationship between the radical wear and interior ballistic characteristics was illuminated theoretically and experimental- ly. The research results show the great value of this criterion to solve the problem of barrel lifetime.

  19. Cubosomes for in vivo fluorescence lifetime imaging.

    Science.gov (United States)

    Biffi, Stefania; Andolfi, Laura; Caltagirone, Claudia; Garrovo, Chiara; Falchi, Angela M; Lippolis, Vito; Lorenzon, Andrea; Macor, Paolo; Meli, Valeria; Monduzzi, Maura; Obiols-Rabasa, Marc; Petrizza, Luca; Prodi, Luca; Rosa, Antonella; Schmidt, Judith; Talmon, Yeshayahu; Murgia, Sergio

    2017-02-03

    Herein we provided the first proof of principle for in vivo fluorescence optical imaging application using monoolein-based cubosomes in a healthy mouse animal model. This formulation, administered at a non-cytotoxic concentration, was capable of providing both exogenous contrast for NIR fluorescence imaging with very high efficiency and chemospecific information upon lifetime analysis. Time-resolved measurements of fluorescence after the intravenous injection of cubosomes revealed that the dye rapidly accumulated mainly in the liver, while lifetimes profiles obtained in vivo allowed for discriminating between free dye or dye embedded within the cubosome nanostructure after injection.

  20. Dumping the decelerated beams of CLIC

    CERN Document Server

    Jeanneret, Bernard

    2011-01-01

    The spent drive beam must be cleanly extracted and bent away from the decelerator axis at the end of each CLIC decelerator in order to leave space for injecting a fresh beam train in the next sector. Then the spent beam must be safely absorbed. A compact extraction system made of a single dipole is proposed. The spent beam is driven to a water dump located at 20m downstream of the extraction point and transversely 6m away of the axis of the main linac. An adequate spread of the beam impact map on the dump offers small temperature excursions in both the dump and its entrance window, allowing for reliable operation and a long lifetime of the system.